Q.1 What is the primary growth factor that stimulates new blood vessel formation during tissue regeneration?
Fibroblast Growth Factor
Vascular Endothelial Growth Factor
Insulin-like Growth Factor
Platelet-Derived Growth Factor
Explanation - VEGF is the main cytokine that induces proliferation and migration of endothelial cells, leading to angiogenesis.
Correct answer is: Vascular Endothelial Growth Factor
Q.2 Which of the following cell types is directly responsible for forming the lumen of new blood vessels?
Fibroblasts
Endothelial cells
Smooth muscle cells
Macrophages
Explanation - Endothelial cells line the interior of blood vessels and create the tubular structure necessary for blood flow.
Correct answer is: Endothelial cells
Q.3 During hypoxia, which signaling pathway is activated to increase VEGF production?
HIF-1α
NF-κB
MAPK
Wnt/β-catenin
Explanation - Hypoxia-inducible factor 1-alpha stabilizes under low oxygen and upregulates VEGF transcription.
Correct answer is: HIF-1α
Q.4 Shear stress on endothelial cells primarily triggers the release of which molecule that promotes vasodilation?
Nitric Oxide
Thromboxane A2
Prostaglandin E2
Endothelin-1
Explanation - Shear stress activates endothelial nitric oxide synthase (eNOS), increasing NO that relaxes vascular smooth muscle.
Correct answer is: Nitric Oxide
Q.5 Which scaffold material is commonly used in tissue engineering to promote angiogenesis due to its inherent porosity?
Polyethylene glycol (PEG)
Collagen
Polystyrene
Gold nanoparticles
Explanation - Collagen scaffolds provide natural binding sites and allow cell infiltration, facilitating vascular ingrowth.
Correct answer is: Collagen
Q.6 What is the role of pericytes in newly formed capillaries?
They form the endothelial lining
They secrete VEGF
They stabilize and mature vessels
They act as immune cells
Explanation - Pericytes wrap around endothelial cells and provide structural support, reducing leakage and promoting vessel stability.
Correct answer is: They stabilize and mature vessels
Q.7 Which of the following is NOT a hallmark of angiogenic sprouting?
Endothelial tip cell formation
Basement membrane degradation
Arteriolar dilation
Lumen formation
Explanation - Arteriolar dilation is not part of sprouting angiogenesis; it occurs during vessel maturation and remodeling.
Correct answer is: Arteriolar dilation
Q.8 In a wound-healing assay, the addition of anti-VEGF antibodies would most likely result in which observation?
Increased vessel density
Decreased vessel density
No change in vessel density
Accelerated wound closure
Explanation - Blocking VEGF inhibits endothelial proliferation and migration, reducing new vessel formation.
Correct answer is: Decreased vessel density
Q.9 Which molecule is a direct downstream target of VEGF receptor activation that promotes endothelial cell proliferation?
Akt
p53
c-Myc
FOXO1
Explanation - VEGFR signaling activates the PI3K/Akt pathway, supporting cell survival and proliferation.
Correct answer is: Akt
Q.10 The ratio of angiogenic to anti-angiogenic factors determines the vascularization outcome. Which anti-angiogenic factor is known to bind VEGF and prevent its activity?
Endostatin
Angiostatin
Thrombospondin-1
Pigment Epithelium-derived Factor
Explanation - Thrombospondin-1 binds to VEGF and its receptors, inhibiting endothelial cell functions and angiogenesis.
Correct answer is: Thrombospondin-1
Q.11 During embryonic development, which signaling pathway is crucial for the specification of arterial endothelial cells?
Notch
TGF-β
JAK/STAT
Calcium signaling
Explanation - Notch signaling, particularly Notch1/Dll4 interaction, drives arterial identity in endothelial cells.
Correct answer is: Notch
Q.12 Which cell-derived extracellular matrix protein serves as a scaffold for endothelial cell migration during angiogenesis?
Fibronectin
Elastin
Laminin
Keratin
Explanation - Fibronectin forms fibrils that guide migrating endothelial cells, providing both structural support and binding sites.
Correct answer is: Fibronectin
Q.13 The term "angiogenic switch" refers to:
The onset of blood vessel regression
The balance shift towards pro-angiogenic factors
The moment when VEGF is first expressed
The switch from arterial to venous development
Explanation - The angiogenic switch occurs when pro-angiogenic signals outweigh anti-angiogenic signals, initiating vessel growth.
Correct answer is: The balance shift towards pro-angiogenic factors
Q.14 Which of the following is a functional consequence of angiogenesis in tissue engineering constructs?
Increased mechanical strength
Decreased oxygen diffusion
Improved nutrient delivery
Reduced cell viability
Explanation - New blood vessels bring oxygen and nutrients deeper into the scaffold, enhancing cell survival and tissue growth.
Correct answer is: Improved nutrient delivery
Q.15 Which enzyme degrades the basement membrane during endothelial sprouting?
Matrix metalloproteinase-9 (MMP-9)
Lysyl oxidase
Collagenase-2
Alkaline phosphatase
Explanation - MMP-9 breaks down extracellular matrix components, allowing endothelial cells to migrate and form new sprouts.
Correct answer is: Matrix metalloproteinase-9 (MMP-9)
Q.16 Which biomaterial property most directly influences endothelial cell attachment for angiogenesis?
Electrical conductivity
Surface hydrophilicity
Magnetic susceptibility
Thermal stability
Explanation - Hydrophilic surfaces promote protein adsorption and integrin-mediated endothelial adhesion, critical for vessel formation.
Correct answer is: Surface hydrophilicity
Q.17 The interaction between which two receptors is essential for tip cell selection during sprouting angiogenesis?
VEGFR2 and neuropilin-1
PDGFR-β and TIE2
EGFR and HER2
CD34 and CD31
Explanation - Tip cells express both VEGFR2 and neuropilin-1, which synergistically respond to VEGF gradients.
Correct answer is: VEGFR2 and neuropilin-1
Q.18 In the context of tumor angiogenesis, what is the primary advantage for the tumor once new vessels form?
Increased immune surveillance
Reduced metabolic waste clearance
Enhanced oxygen and nutrient supply
Decreased cell proliferation
Explanation - Tumors use new vasculature to sustain rapid growth and metastasis by providing necessary nutrients and oxygen.
Correct answer is: Enhanced oxygen and nutrient supply
Q.19 Which of the following best describes the process of vasculogenesis?
Sprouting of new vessels from existing ones
Formation of vessels from endothelial progenitor cells
Pruning of immature vessels
Maturation of capillaries
Explanation - Vasculogenesis involves de novo vessel formation by differentiation of progenitor cells into endothelial cells.
Correct answer is: Formation of vessels from endothelial progenitor cells
Q.20 Which anti-angiogenic therapy targets the VEGF pathway by binding directly to VEGF?
Bevacizumab
Sorafenib
Imatinib
Tamoxifen
Explanation - Bevacizumab is a monoclonal antibody that neutralizes VEGF, preventing it from activating VEGFR on endothelial cells.
Correct answer is: Bevacizumab
Q.21 Which type of endothelial cell is typically involved in the formation of larger blood vessels during arteriogenesis?
Tip cells
Stalk cells
Smooth muscle cells
Macrophage-derived cells
Explanation - Stalk cells proliferate and elongate between tip cells, forming the backbone of new vessels that mature into larger arteries.
Correct answer is: Stalk cells
Q.22 During tissue repair, macrophages release which cytokine that stimulates endothelial cell proliferation?
Interleukin-10
Tumor necrosis factor-alpha (TNF-α)
Interleukin-8 (IL-8)
Transforming growth factor-beta (TGF-β)
Explanation - IL-8 is a potent chemoattractant for endothelial cells and enhances their proliferation during angiogenesis.
Correct answer is: Interleukin-8 (IL-8)
Q.23 Which of the following is a hallmark feature of a mature, functional capillary?
Multiple endothelial layers
Absence of basement membrane
Presence of pericytes
Large lumen diameter
Explanation - Pericytes stabilize capillaries, regulate permeability, and are essential for mature vascular function.
Correct answer is: Presence of pericytes
Q.24 Which signaling pathway is primarily responsible for endothelial cell migration towards VEGF gradients?
JAK/STAT
PI3K/Akt
Wnt/β-catenin
Rho/ROCK
Explanation - Rho/ROCK signaling modulates cytoskeletal dynamics, enabling directional migration of endothelial cells.
Correct answer is: Rho/ROCK
Q.25 In tissue engineering, what is the purpose of incorporating endothelial progenitor cells (EPCs) into a scaffold?
To enhance mechanical strength
To provide electrical conductivity
To promote in situ vascularization
To reduce scaffold degradation rate
Explanation - EPCs can differentiate into endothelial cells and form new vessels within the scaffold, improving tissue integration.
Correct answer is: To promote in situ vascularization
Q.26 Which of the following best describes the role of the Notch ligand Dll4 in angiogenesis?
It inhibits endothelial cell proliferation
It promotes tip cell formation and branching
It stabilizes basement membrane
It induces smooth muscle differentiation
Explanation - Dll4 activates Notch signaling to regulate tip/stalk cell selection, controlling vessel branching patterns.
Correct answer is: It promotes tip cell formation and branching
Q.27 Which imaging technique is commonly used to visualize angiogenesis in vivo?
MRI
Ultrasound
Fluorescence microscopy
Computed tomography (CT) angiography
Explanation - CT angiography provides high-resolution images of blood vessels, enabling assessment of angiogenic changes.
Correct answer is: Computed tomography (CT) angiography
Q.28 Which of the following is NOT typically released by endothelial cells during angiogenic sprouting?
VEGF
Angiopoietin-1
Platelet-derived growth factor
Endothelin-1
Explanation - Endothelin-1 is a vasoconstrictor, not a pro-angiogenic factor usually secreted during sprouting.
Correct answer is: Endothelin-1
Q.29 What is the primary function of perivascular macrophages during angiogenesis?
To supply oxygen to the nascent vessels
To secrete anti-inflammatory cytokines
To remove apoptotic endothelial cells
To form the basement membrane
Explanation - Macrophages clear dying endothelial cells and debris, allowing new sprouts to form properly.
Correct answer is: To remove apoptotic endothelial cells
Q.30 Which biomolecule is known to inhibit VEGF signaling by binding to its receptor extracellular domain?
Endostatin
Thrombospondin-1
Angiostatin
All of the above
Explanation - All listed molecules can bind VEGFR or VEGF itself, blocking downstream signaling and angiogenesis.
Correct answer is: All of the above
Q.31 During the maturation of a new vessel, which cell type typically migrates into the vessel wall to provide structural support?
Endothelial progenitor cells
Fibroblasts
Smooth muscle cells
Neutrophils
Explanation - Smooth muscle cells wrap around mature vessels, strengthening them and regulating diameter.
Correct answer is: Smooth muscle cells
Q.32 What is the main difference between angiogenesis and arteriogenesis?
Angiogenesis forms new vessels; arteriogenesis remodels existing ones
Arteriogenesis forms new vessels; angiogenesis remodels existing ones
Both involve new vessel formation from scratch
Both involve vessel remodeling with no new formation
Explanation - Angiogenesis creates new capillaries, whereas arteriogenesis enlarges pre-existing collateral vessels.
Correct answer is: Angiogenesis forms new vessels; arteriogenesis remodels existing ones
Q.33 Which of the following is a direct effect of hypoxia on endothelial cells?
Decreased VEGF secretion
Increased VEGF secretion
Inhibition of proliferation
Reduced migration
Explanation - Hypoxia activates HIF-1α, leading to upregulation of VEGF that promotes angiogenesis.
Correct answer is: Increased VEGF secretion
Q.34 Which of these molecules functions as an extracellular matrix-bound angiogenic inhibitor?
Fibronectin
Heparan sulfate
Syndecan-1
Endostatin
Explanation - Endostatin binds to VEGFR and extracellular matrix components, preventing endothelial cell activation.
Correct answer is: Endostatin
Q.35 What role does shear stress play in the orientation of endothelial cells during vessel remodeling?
It has no effect on orientation
It aligns cells perpendicular to flow
It aligns cells parallel to flow
It causes random orientation
Explanation - Shear stress directs endothelial cells to align in the direction of blood flow, optimizing vascular function.
Correct answer is: It aligns cells parallel to flow
Q.36 Which signaling molecule is secreted by smooth muscle cells to attract endothelial cells during angiogenesis?
Angiopoietin-1
Angiopoietin-2
VEGF
PDGF-BB
Explanation - PDGF-BB from smooth muscle cells recruits endothelial progenitor cells and stabilizes new vessels.
Correct answer is: PDGF-BB
Q.37 During endothelial sprouting, which cell surface receptor is upregulated to enhance sensitivity to VEGF?
VEGFR1
VEGFR2
VEGFR3
VEGFR4
Explanation - VEGFR2 is the main mediator of VEGF-induced endothelial cell proliferation and migration.
Correct answer is: VEGFR2
Q.38 Which of the following is a clinical indicator that angiogenesis is occurring in a regenerating tissue?
Reduced capillary density
Increased expression of collagen type I
Elevated levels of VEGF and CD31 staining
Decreased oxygen tension
Explanation - High VEGF promotes vessel growth and CD31 is an endothelial marker indicating new vasculature.
Correct answer is: Elevated levels of VEGF and CD31 staining
Q.39 In tissue scaffolds, which pore size range is considered optimal for endothelial cell infiltration and vessel formation?
1–10 µm
20–100 µm
200–500 µm
≥ 1 mm
Explanation - Pores between 20–100 µm allow endothelial cells to migrate and form capillary networks.
Correct answer is: 20–100 µm
Q.40 Which transcription factor is directly induced by VEGF signaling to promote endothelial cell migration?
FOXO3
NF-κB
Ets-1
p53
Explanation - VEGF activates the Ets-1 pathway, which controls genes necessary for migration and sprouting.
Correct answer is: Ets-1
Q.41 Which of the following is NOT an anti-angiogenic therapy mechanism?
VEGF sequestration
Inhibition of endothelial cell proliferation
Promotion of endothelial cell migration
Blockage of VEGFR signaling
Explanation - Anti-angiogenic therapies inhibit migration to prevent new vessel formation.
Correct answer is: Promotion of endothelial cell migration
Q.42 Which cytokine is primarily responsible for recruiting monocytes that differentiate into macrophages during wound healing?
IL-1β
IL-6
Monocyte Chemoattractant Protein-1 (MCP-1)
TNF-α
Explanation - MCP-1 guides monocytes to the wound site where they become macrophages, supporting angiogenesis.
Correct answer is: Monocyte Chemoattractant Protein-1 (MCP-1)
Q.43 What is the primary purpose of the basement membrane during angiogenesis?
To act as a nutrient reservoir
To provide structural support and regulate cell migration
To serve as a barrier to immune cells
To store growth factors for later release
Explanation - The basement membrane offers a scaffold and biochemical cues guiding endothelial movement.
Correct answer is: To provide structural support and regulate cell migration
Q.44 Which of the following is a hallmark of the transition from sprouting to maturation in new blood vessels?
Decreased expression of VEGFR2
Increased pericyte coverage
Loss of endothelial cells
Reduction in lumen diameter
Explanation - Pericytes attach to vessels during maturation, stabilizing the structure and regulating permeability.
Correct answer is: Increased pericyte coverage
Q.45 Which molecule is secreted by endothelial cells to attract smooth muscle progenitor cells during vessel maturation?
Angiopoietin-2
Angiopoietin-1
VEGF
PDGF-BB
Explanation - Angiopoietin-1 binds TIE2 on smooth muscle cells, encouraging recruitment and vessel stabilization.
Correct answer is: Angiopoietin-1
Q.46 What is the main effect of hypoxia on the expression of the VEGF gene?
Downregulation via HIF-1α
Upregulation via HIF-1α
No change
Downregulation via mTOR
Explanation - HIF-1α stabilizes under low oxygen, binding to the VEGF promoter and increasing transcription.
Correct answer is: Upregulation via HIF-1α
Q.47 Which of these cell types is considered the most potent source of endothelial progenitor cells in peripheral blood?
Neutrophils
Monocytes
Hematopoietic stem cells
Erythrocytes
Explanation - Hematopoietic stem cells can differentiate into EPCs that contribute to vasculogenesis.
Correct answer is: Hematopoietic stem cells
Q.48 Which of the following is a key indicator that angiogenesis is inhibited in a tumor microenvironment?
High microvessel density
Elevated VEGF expression
Low microvessel density
Increased pericyte coverage
Explanation - Reduced vessel density indicates effective anti-angiogenic therapy or natural inhibition.
Correct answer is: Low microvessel density
Q.49 Which scaffold fabrication technique allows precise control over pore interconnectivity for angiogenic studies?
Electrospinning
3D bioprinting
Solvent casting
Freeze-drying
Explanation - 3D bioprinting can design scaffolds with defined pore size and connectivity, essential for vascular ingrowth.
Correct answer is: 3D bioprinting
Q.50 Which protein family is commonly used as a marker to identify endothelial cells in histological sections?
Integrins
Cadherins
Claudins
CD31 (PECAM-1)
Explanation - CD31 is a membrane protein specific to endothelial cells, widely used for vascular staining.
Correct answer is: CD31 (PECAM-1)
Q.51 During the early phase of angiogenesis, what is the primary source of VEGF?
Endothelial cells
Fibroblasts
Macrophages
Smooth muscle cells
Explanation - Macrophages release VEGF in response to hypoxia and injury, initiating endothelial sprouting.
Correct answer is: Macrophages
Q.52 Which of the following describes the role of matrix metalloproteinases (MMPs) in angiogenesis?
They inhibit VEGF secretion
They degrade extracellular matrix to allow endothelial migration
They stabilize the basement membrane
They promote endothelial cell apoptosis
Explanation - MMPs remodel the matrix, clearing pathways for migrating endothelial cells.
Correct answer is: They degrade extracellular matrix to allow endothelial migration
Q.53 Which of the following is an endothelial tip cell marker?
VE-Cadherin
Delta-like ligand 4 (Dll4)
Tie2
Angiopoietin-2
Explanation - Dll4 is expressed on tip cells, guiding their migration toward VEGF gradients.
Correct answer is: Delta-like ligand 4 (Dll4)
Q.54 In tissue regeneration, which factor is most critical for converting fibroblasts into myofibroblasts?
TGF-β
VEGF
IGF-1
Epidermal growth factor
Explanation - TGF-β promotes differentiation of fibroblasts into contractile myofibroblasts, influencing vascular remodeling.
Correct answer is: TGF-β
Q.55 Which of the following best explains why scaffolds with anisotropic pores can enhance directional angiogenesis?
They provide uniform stiffness
They guide endothelial cells along defined pathways
They reduce cell adhesion
They increase scaffold porosity uniformly
Explanation - Anisotropic pores create directional cues, directing sprouting in specific orientations.
Correct answer is: They guide endothelial cells along defined pathways
Q.56 Which cytokine is primarily responsible for inducing smooth muscle cell proliferation during vessel maturation?
VEGF
Platelet-derived growth factor (PDGF)
IL-10
TNF-α
Explanation - PDGF signals smooth muscle cells to proliferate and migrate, contributing to vessel wall formation.
Correct answer is: Platelet-derived growth factor (PDGF)
Q.57 Which of the following is an example of an endothelial cell apoptosis inhibitor used during angiogenesis?
Caspase-3
Bcl-2
p53
Cytochrome c
Explanation - Bcl-2 is an anti-apoptotic protein that helps endothelial cells survive during vessel formation.
Correct answer is: Bcl-2
Q.58 Which of the following is the primary source of endothelial cells in vasculogenesis within the developing embryo?
Skeletal muscle
Heart valve
Mesodermal progenitors
Neural crest cells
Explanation - Mesodermal progenitor cells differentiate into endothelial cells to form the vascular network.
Correct answer is: Mesodermal progenitors
Q.59 Which of the following best describes the role of the Angiopoietin/Tie signaling pathway in angiogenesis?
Initiates sprouting by VEGF
Regulates vessel maturation and stabilization
Promotes endothelial apoptosis
Degrades the extracellular matrix
Explanation - Angiopoietin-1/Tie2 promotes vessel maturation; Angiopoietin-2/Tie2 destabilizes vessels for remodeling.
Correct answer is: Regulates vessel maturation and stabilization
Q.60 What is the primary function of endothelial nitric oxide synthase (eNOS) during angiogenesis?
Inhibit endothelial proliferation
Stimulate angiogenic sprouting by increasing NO
Promote endothelial apoptosis
Trigger smooth muscle cell contraction
Explanation - NO diffuses to surrounding cells, promoting vasodilation and sprout formation.
Correct answer is: Stimulate angiogenic sprouting by increasing NO
Q.61 Which of the following is a known angiogenic stimulant used clinically in wound dressings?
Platelet lysate
Heparin
Chondroitin sulfate
Silicone
Explanation - Platelet lysate releases growth factors, including VEGF and PDGF, encouraging angiogenesis in wounds.
Correct answer is: Platelet lysate
Q.62 During tissue regeneration, which molecule is responsible for establishing the initial chemotactic gradient for endothelial cells?
VEGF
Epidermal growth factor (EGF)
Insulin
Glucagon
Explanation - VEGF creates a concentration gradient that directs endothelial cells toward hypoxic or wounded areas.
Correct answer is: VEGF
Q.63 What is the effect of an excess of MMP-2 activity on angiogenesis?
Increased vessel stability
Inhibited endothelial migration
Enhanced extracellular matrix degradation
Reduced angiogenic sprouting
Explanation - High MMP-2 activity breaks down ECM, allowing endothelial cells to migrate more freely.
Correct answer is: Enhanced extracellular matrix degradation
Q.64 Which of the following is NOT a component of the endothelial cell junctional complex that maintains vessel integrity?
VE-Cadherin
Claudin-5
Occludin
Integrin α5β1
Explanation - Integrins mediate adhesion to ECM, not junction formation; VE-Cadherin, Claudin-5, and Occludin form tight junctions.
Correct answer is: Integrin α5β1
Q.65 Which of the following describes the primary function of pericytes during capillary formation?
To form the basal lamina
To regulate capillary blood flow and permeability
To produce VEGF
To act as immune sentinels
Explanation - Pericytes wrap around endothelial cells, controlling vessel diameter and barrier function.
Correct answer is: To regulate capillary blood flow and permeability
Q.66 What is the main role of the extracellular matrix protein laminin during angiogenesis?
To inhibit endothelial migration
To serve as a scaffold for endothelial cell adhesion and migration
To block VEGF binding
To induce endothelial cell apoptosis
Explanation - Laminin interacts with integrins, guiding endothelial cells through the matrix during sprouting.
Correct answer is: To serve as a scaffold for endothelial cell adhesion and migration
Q.67 Which of the following growth factors is primarily released by fibroblasts to support angiogenesis?
Vascular endothelial growth factor (VEGF)
Platelet-derived growth factor (PDGF)
Fibroblast growth factor (FGF)
Interleukin-6 (IL-6)
Explanation - FGF stimulates endothelial cell proliferation and migration, complementing VEGF actions.
Correct answer is: Fibroblast growth factor (FGF)
Q.68 Which signaling cascade is activated downstream of VEGFR2 to promote endothelial cell migration?
JAK/STAT
PI3K/Akt
Wnt/β-catenin
Ras/Raf/MEK/ERK
Explanation - VEGFR2 activation triggers the MAPK pathway, driving cytoskeletal reorganization for migration.
Correct answer is: Ras/Raf/MEK/ERK
Q.69 What is the primary role of platelet-derived growth factor-BB (PDGF-BB) in vessel maturation?
Stimulates endothelial cell proliferation
Recruits smooth muscle cells to the vessel wall
Inhibits MMP activity
Promotes pericyte apoptosis
Explanation - PDGF-BB binds to PDGFR-β on smooth muscle cells, guiding them to encircle new vessels.
Correct answer is: Recruits smooth muscle cells to the vessel wall
Q.70 Which of the following molecules is known to bind to and sequester VEGF, thus acting as an angiogenesis inhibitor?
Heparin
Endostatin
Fibronectin
Collagen type IV
Explanation - Endostatin directly binds VEGF, preventing receptor interaction and inhibiting angiogenesis.
Correct answer is: Endostatin
Q.71 Which type of endothelial cell is primarily involved in forming new arteries during arteriogenesis?
Tip cells
Stalk cells
Lumen cells
Skeletal endothelial cells
Explanation - Stalk cells elongate and form the structural backbone of new arteries during arteriogenesis.
Correct answer is: Stalk cells
Q.72 During the early stages of tissue regeneration, which cell type releases nitric oxide to promote vasodilation?
Endothelial cells
Fibroblasts
Macrophages
Neutrophils
Explanation - Endothelial nitric oxide synthase in endothelial cells produces NO, facilitating vessel dilation.
Correct answer is: Endothelial cells
Q.73 Which of the following describes the term "angiogenic priming"?
Preconditioning a scaffold with growth factors to enhance vessel ingrowth
The activation of endothelial cells by VEGF
The maturation of vessels after sprouting
The inhibition of angiogenesis by anti-VEGF
Explanation - Angiogenic priming refers to seeding scaffolds with factors like VEGF to accelerate vascularization.
Correct answer is: Preconditioning a scaffold with growth factors to enhance vessel ingrowth
Q.74 Which of the following is a common method to assess microvessel density in tissue samples?
ELISA for VEGF
Immunohistochemical staining for CD31
Western blot for eNOS
Flow cytometry for CD34
Explanation - CD31 staining visualizes endothelial cells, allowing quantification of vessel density.
Correct answer is: Immunohistochemical staining for CD31
Q.75 Which of the following best explains why shear stress is important for the orientation of endothelial cells in a blood vessel?
It forces cells to align perpendicular to flow
It has no effect on cell orientation
It forces cells to align parallel to flow
It causes random orientation
Explanation - Shear stress directs endothelial cells to align with the direction of blood flow for efficient transport.
Correct answer is: It forces cells to align parallel to flow
Q.76 Which of the following is a key factor that inhibits the migration of endothelial cells during angiogenesis?
Thrombospondin-1
VEGF
FGF-2
PDGF-BB
Explanation - Thrombospondin-1 binds to endothelial receptors, inhibiting migration and proliferation.
Correct answer is: Thrombospondin-1
Q.77 In the context of tissue scaffolds, what is the significance of porosity?
Higher porosity reduces nutrient diffusion
Lower porosity increases cell infiltration
Optimal porosity allows cell migration and vessel ingrowth
Porosity is unrelated to angiogenesis
Explanation - Adequate porosity provides pathways for cells and vessels to populate the scaffold.
Correct answer is: Optimal porosity allows cell migration and vessel ingrowth
Q.78 Which of the following molecules is released by smooth muscle cells to attract endothelial cells during angiogenesis?
Angiopoietin-1
Angiopoietin-2
VEGF
PDGF-BB
Explanation - Angiopoietin-1 binds TIE2 on endothelial cells, facilitating vessel maturation.
Correct answer is: Angiopoietin-1
Q.79 Which of the following best describes the role of the basement membrane during endothelial sprouting?
It provides a rigid barrier
It guides endothelial cells by providing structural cues
It inhibits endothelial proliferation
It is dissolved immediately during sprouting
Explanation - The basement membrane is remodeled to allow endothelial migration while maintaining guidance.
Correct answer is: It guides endothelial cells by providing structural cues
Q.80 What is the role of the integrin αvβ3 in angiogenesis?
It inhibits endothelial cell adhesion
It promotes endothelial cell migration and survival
It binds VEGF directly
It degrades extracellular matrix
Explanation - αvβ3 integrin interacts with ECM proteins, facilitating migration and signaling for survival.
Correct answer is: It promotes endothelial cell migration and survival
Q.81 Which of the following is a hallmark of endothelial tip cells during sprouting angiogenesis?
High expression of VEGFR1
High expression of VEGFR2 and Dll4
High expression of Notch1
High expression of Tie2
Explanation - Tip cells exhibit high VEGFR2 and Dll4 to sense gradients and guide sprouting.
Correct answer is: High expression of VEGFR2 and Dll4
Q.82 Which of the following is a characteristic of a mature, stabilized vessel?
Low pericyte coverage
High endothelial permeability
Presence of smooth muscle cells
High MMP activity
Explanation - Mature vessels are surrounded by smooth muscle cells, enhancing stability and regulating flow.
Correct answer is: Presence of smooth muscle cells
Q.83 What is the primary function of the transcription factor HIF-1α during hypoxia?
To downregulate VEGF expression
To upregulate VEGF expression
To promote apoptosis
To inhibit angiogenesis
Explanation - HIF-1α activates VEGF transcription under low oxygen conditions, initiating angiogenesis.
Correct answer is: To upregulate VEGF expression
Q.84 Which of the following molecules is an endothelial cell-derived factor that attracts pericytes during vessel maturation?
Angiopoietin-2
Angiopoietin-1
VEGF
PDGF-BB
Explanation - Angiopoietin-1/Tie2 signaling recruits pericytes and smooth muscle cells for vessel stabilization.
Correct answer is: Angiopoietin-1
Q.85 What is the main difference between sprouting angiogenesis and intussusceptive angiogenesis?
Sprouting requires endothelial proliferation; intussusception does not
Intussusception requires pericyte recruitment; sprouting does not
Sprouting involves vessel splitting; intussusception involves new vessel formation
Intussusception requires VEGF; sprouting does not
Explanation - Sprouting creates new vessels by endothelial migration; intussusception expands existing vessels by splitting.
Correct answer is: Sprouting involves vessel splitting; intussusception involves new vessel formation
Q.86 Which of the following is a direct downstream target of VEGF signaling that promotes endothelial cell survival?
Akt
p53
BAX
Caspase-9
Explanation - VEGF activates PI3K/Akt signaling, which promotes survival and proliferation.
Correct answer is: Akt
Q.87 Which cell type contributes to the formation of the provisional matrix during early wound healing?
Endothelial cells
Fibroblasts
Macrophages
Neutrophils
Explanation - Macrophages release matrix metalloproteinases and growth factors, forming the provisional matrix.
Correct answer is: Macrophages
Q.88 In the context of angiogenesis, what is the role of the protein TIE2?
It acts as a VEGF receptor
It regulates endothelial cell junctions
It serves as a receptor for angiopoietins
It degrades extracellular matrix
Explanation - TIE2 is activated by angiopoietin-1 or -2, influencing vessel maturation and stability.
Correct answer is: It serves as a receptor for angiopoietins
Q.89 Which of the following best explains why a scaffold containing VEGF can accelerate tissue regeneration?
VEGF binds to collagen to strengthen the scaffold
VEGF directly stimulates fibroblast migration
VEGF attracts endothelial cells to form new blood vessels
VEGF reduces inflammation
Explanation - VEGF is a potent chemotactic factor for endothelial cells, promoting vascularization of the scaffold.
Correct answer is: VEGF attracts endothelial cells to form new blood vessels
Q.90 What is the primary function of the enzyme matrix metalloproteinase-9 (MMP-9) during angiogenesis?
To inhibit VEGF secretion
To degrade the basement membrane and ECM
To promote endothelial cell adhesion
To stimulate smooth muscle differentiation
Explanation - MMP-9 removes matrix barriers, allowing endothelial cells to migrate and form sprouts.
Correct answer is: To degrade the basement membrane and ECM
Q.91 Which of the following is a common therapeutic approach to stimulate angiogenesis in ischemic tissue?
Administration of anti-VEGF antibodies
Local delivery of VEGF
Systemic administration of corticosteroids
Use of nitric oxide donors only
Explanation - Delivering VEGF locally increases angiogenic signaling in the ischemic region.
Correct answer is: Local delivery of VEGF
Q.92 Which of the following best describes the role of the Notch signaling pathway in angiogenesis?
It stimulates endothelial cell migration
It regulates tip/stalk cell selection during sprouting
It inhibits smooth muscle recruitment
It is unrelated to vascular development
Explanation - Notch signaling, particularly via Dll4, determines which endothelial cells become tip or stalk cells.
Correct answer is: It regulates tip/stalk cell selection during sprouting
Q.93 Which of the following molecules is a key marker for identifying endothelial progenitor cells (EPCs) in peripheral blood?
CD34
CD45
CD14
CD3
Explanation - CD34 is expressed on EPCs and helps isolate them from blood samples.
Correct answer is: CD34
Q.94 Which of the following best explains why increased pericyte coverage leads to reduced vascular permeability?
Pericytes produce VEGF
Pericytes form a barrier around endothelial cells
Pericytes increase basement membrane thickness
Pericytes secrete MMPs
Explanation - Pericyte coverage tightens junctions and limits leakiness, stabilizing vessels.
Correct answer is: Pericytes form a barrier around endothelial cells
Q.95 Which of the following molecules directly antagonizes VEGF binding to its receptors?
Endostatin
Angiostatin
Thrombospondin-1
All of the above
Explanation - Endostatin, angiostatin, and thrombospondin-1 can bind VEGF or its receptors, blocking angiogenesis.
Correct answer is: All of the above
Q.96 Which of the following is a major source of nitric oxide during early angiogenesis?
Smooth muscle cells
Endothelial cells
Fibroblasts
Macrophages
Explanation - Endothelial nitric oxide synthase in endothelial cells produces NO, promoting vasodilation and sprouting.
Correct answer is: Endothelial cells
Q.97 Which of the following processes is responsible for the formation of new vessels from existing ones?
Vasculogenesis
Angiogenesis
Arteriogenesis
Metaplasia
Explanation - Angiogenesis describes new vessel growth from pre-existing vessels.
Correct answer is: Angiogenesis
Q.98 Which of the following is a primary mechanism by which shear stress influences endothelial cell behavior?
Activation of integrin-mediated adhesion
Stimulation of eNOS and NO production
Inhibition of VEGF expression
Promotion of MMP activity
Explanation - Shear stress activates eNOS, increasing NO and regulating endothelial alignment.
Correct answer is: Stimulation of eNOS and NO production
Q.99 Which of the following is a typical feature of a sprouting endothelial tip cell?
High expression of VE-cadherin
High number of filopodia
Low proliferation rate
Pericyte association
Explanation - Tip cells extend filopodia to sense VEGF gradients during sprouting.
Correct answer is: High number of filopodia
Q.100 Which molecule is known to recruit endothelial progenitor cells into the bloodstream?
CXCL12
IL-2
TNF-α
IGF-1
Explanation - CXCL12 (SDF-1) is a chemoattractant for EPCs and promotes their homing to injury sites.
Correct answer is: CXCL12
Q.101 Which of the following is NOT a characteristic of endothelial cells in a mature, stable vessel?
Presence of tight junctions
Absence of pericyte coverage
Low permeability
Expression of CD31
Explanation - Stable vessels are wrapped by pericytes, which are essential for stability.
Correct answer is: Absence of pericyte coverage
Q.102 Which growth factor is essential for the recruitment of smooth muscle cells to nascent vessels?
PDGF-BB
VEGF
TGF-β
EGF
Explanation - PDGF-BB signals smooth muscle cells to migrate and differentiate around new vessels.
Correct answer is: PDGF-BB
Q.103 Which of the following best describes the process by which endothelial cells form new lumens during angiogenesis?
Apoptosis of central cells
Cell migration into the center of a tube
Formation of a hollow channel through rearrangement of actin
Secretion of basement membrane proteins
Explanation - Actin cytoskeleton reorganization allows cells to create a lumen within the sprout.
Correct answer is: Formation of a hollow channel through rearrangement of actin
Q.104 Which of the following is a key mediator released by endothelial cells that can attract macrophages?
VEGF
IL-8
TGF-β
IL-10
Explanation - IL-8 is a chemokine that attracts neutrophils and macrophages to sites of angiogenesis.
Correct answer is: IL-8
Q.105 Which of the following is a main function of matrix metalloproteinase-2 (MMP-2) during angiogenesis?
Inhibition of VEGF
Promotion of endothelial cell adhesion
Degradation of the extracellular matrix
Activation of Notch signaling
Explanation - MMP-2 cleaves ECM components, enabling endothelial cells to invade surrounding tissue.
Correct answer is: Degradation of the extracellular matrix
Q.106 Which of the following is a hallmark of the early inflammatory phase of wound healing?
Granulation tissue formation
Fibroblast proliferation
Macrophage infiltration and secretion of growth factors
Collagen deposition
Explanation - Macrophages release VEGF and other factors that initiate angiogenesis during wound healing.
Correct answer is: Macrophage infiltration and secretion of growth factors
Q.107 Which molecule is known to be a potent anti-angiogenic factor secreted by tumor cells in hypoxic microenvironments?
HIF-1α
Endostatin
VEGF
FGF-2
Explanation - Tumor cells can secrete endostatin to inhibit excessive angiogenesis, creating a hypoxic niche.
Correct answer is: Endostatin
Q.108 Which of the following describes the primary difference between vasculogenesis and angiogenesis?
Vasculogenesis is de novo vessel formation; angiogenesis is sprouting from existing vessels
Angiogenesis is de novo vessel formation; vasculogenesis is sprouting
Both involve endothelial proliferation only
Both involve pericyte recruitment only
Explanation - Vasculogenesis originates from progenitor cells; angiogenesis expands existing vessels.
Correct answer is: Vasculogenesis is de novo vessel formation; angiogenesis is sprouting from existing vessels
Q.109 Which of the following is a key factor that promotes the survival of endothelial cells during angiogenesis?
TNF-α
VEGF
IL-10
Cytokine storm
Explanation - VEGF activates survival pathways such as PI3K/Akt in endothelial cells.
Correct answer is: VEGF
Q.110 Which of the following molecules is a receptor for angiopoietin-1?
VEGFR1
VEGFR2
TIE2
PDGFR
Explanation - TIE2 is activated by angiopoietin-1, promoting vessel maturation and stability.
Correct answer is: TIE2
Q.111 Which of the following best describes the role of shear stress in vessel remodeling?
It has no effect on remodeling
It causes endothelial cells to detach
It directs endothelial cell alignment and influences lumen diameter
It reduces nitric oxide production
Explanation - Shear stress guides endothelial orientation and can widen or narrow vessel diameter during remodeling.
Correct answer is: It directs endothelial cell alignment and influences lumen diameter
Q.112 Which of the following is a characteristic of tip cells in angiogenic sprouts?
High expression of VEGFR1
Low expression of Dll4
High expression of VEGFR2 and Dll4
Presence of pericytes
Explanation - Tip cells are highly responsive to VEGF and express Dll4 to interact with Notch on neighboring cells.
Correct answer is: High expression of VEGFR2 and Dll4
Q.113 Which of the following best describes the action of anti-VEGF antibodies in cancer therapy?
They stimulate VEGF production
They block VEGF from binding to its receptors
They increase endothelial cell proliferation
They promote angiogenesis
Explanation - Anti-VEGF antibodies bind VEGF, preventing it from activating VEGFR on endothelial cells.
Correct answer is: They block VEGF from binding to its receptors
Q.114 Which of the following molecules is directly secreted by fibroblasts to enhance angiogenesis?
FGF-2
IL-6
TNF-α
IFN-γ
Explanation - FGF-2 stimulates endothelial cell proliferation and migration during vessel formation.
Correct answer is: FGF-2
Q.115 Which of the following processes involves the division of existing vessels to form new branches?
Intussusception
Vasculogenesis
Angiogenesis
Arteriogenesis
Explanation - Intussusception splits an existing vessel into two by forming a partition within the lumen.
Correct answer is: Intussusception
Q.116 Which of the following is a key marker used to identify mature endothelial cells in histological sections?
CD34
CD31
CD45
CD3
Explanation - CD31 (PECAM-1) is an endothelial cell marker used for vascular staining.
Correct answer is: CD31
Q.117 What is the primary function of the basement membrane during endothelial sprouting?
To inhibit endothelial proliferation
To provide a scaffold for endothelial cell adhesion and migration
To act as a barrier to immune cell infiltration
To secrete growth factors
Explanation - The basement membrane guides endothelial cells and is remodeled during sprouting.
Correct answer is: To provide a scaffold for endothelial cell adhesion and migration
Q.118 Which of the following best describes the role of pericytes during vessel maturation?
They secrete VEGF to promote endothelial proliferation
They stabilize vessels and regulate permeability
They recruit immune cells to the wound site
They degrade the extracellular matrix
Explanation - Pericytes attach to endothelial cells, reducing leakage and supporting vessel stability.
Correct answer is: They stabilize vessels and regulate permeability
Q.119 Which of the following is a main component of the extracellular matrix that promotes endothelial cell adhesion?
Collagen I
Elastin
Fibronectin
Keratin
Explanation - Fibronectin interacts with integrins to facilitate endothelial cell adhesion and migration.
Correct answer is: Fibronectin
Q.120 Which of the following molecules is NOT involved in the regulation of angiogenesis?
VEGF
Angiopoietin-2
TGF-β
Hemoglobin
Explanation - Hemoglobin is not a signaling molecule; VEGF, angiopoietin-2, and TGF-β are key angiogenic regulators.
Correct answer is: Hemoglobin
Q.121 Which of the following best explains why hypoxia induces angiogenesis?
It reduces VEGF expression
It stabilizes HIF-1α, leading to increased VEGF transcription
It increases oxygen supply directly
It inhibits endothelial migration
Explanation - HIF-1α accumulates under low oxygen, activating VEGF expression and stimulating angiogenesis.
Correct answer is: It stabilizes HIF-1α, leading to increased VEGF transcription
Q.122 Which of the following is a typical feature of endothelial tip cells during angiogenic sprouting?
High expression of tight junction proteins
High number of filopodia
Low proliferation rate
Pericyte coverage
Explanation - Tip cells extend filopodia to navigate towards VEGF gradients during sprouting.
Correct answer is: High number of filopodia
Q.123 Which of the following molecules is released by macrophages to promote angiogenesis in wound healing?
IL-10
IL-8
TNF-α
IFN-γ
Explanation - IL-8 acts as a chemoattractant for endothelial cells, fostering new vessel formation.
Correct answer is: IL-8
Q.124 Which of the following is NOT a characteristic of mature capillaries?
Presence of pericytes
Single layer of endothelial cells
High permeability
Lack of smooth muscle cells
Explanation - Mature capillaries have tight junctions and reduced permeability due to pericyte support.
Correct answer is: High permeability
Q.125 Which of the following best explains how endothelial cells sense VEGF gradients?
Through VEGF receptors on their surface
By secreting VEGF themselves
By binding to integrins
By producing MMPs
Explanation - VEGF receptors (especially VEGFR2) detect VEGF concentration differences, guiding migration.
Correct answer is: Through VEGF receptors on their surface
Q.126 Which of the following is a key regulator of pericyte recruitment during angiogenesis?
VEGF
Angiopoietin-2
Platelet-derived growth factor (PDGF)
TGF-β
Explanation - PDGF-BB from endothelial cells signals pericytes to associate with new vessels.
Correct answer is: Platelet-derived growth factor (PDGF)
Q.127 Which of the following describes the role of integrin αvβ3 during angiogenesis?
It inhibits endothelial cell migration
It promotes endothelial cell survival and migration
It binds VEGF directly
It degrades extracellular matrix
Explanation - αvβ3 integrin interacts with ECM, activating signaling pathways that support angiogenesis.
Correct answer is: It promotes endothelial cell survival and migration
Q.128 Which of the following molecules is a direct downstream target of VEGF signaling that promotes endothelial cell survival?
Akt
p53
BAX
Caspase-9
Explanation - VEGF activates the PI3K/Akt pathway, which promotes survival and proliferation in endothelial cells.
Correct answer is: Akt
Q.129 Which of the following best explains why scaffold porosity is crucial for angiogenesis?
It decreases scaffold stiffness
It allows endothelial cells to infiltrate and form vessels
It reduces nutrient diffusion
It prevents immune cell infiltration
Explanation - Adequate pore size and connectivity permit cell migration and vascular ingrowth.
Correct answer is: It allows endothelial cells to infiltrate and form vessels
Q.130 Which of the following is an anti-angiogenic factor secreted by tumor cells?
VEGF
Angiostatin
FGF-2
PDGF
Explanation - Angiostatin binds to endothelial cells and inhibits angiogenic signaling.
Correct answer is: Angiostatin
Q.131 Which of the following is a hallmark of the inflammatory phase of wound healing?
Fibroblast proliferation
Granulation tissue formation
Collagen deposition
Macrophage infiltration and secretion of cytokines
Explanation - Macrophages release cytokines like VEGF that initiate angiogenesis during inflammation.
Correct answer is: Macrophage infiltration and secretion of cytokines
Q.132 Which of the following is a typical response of endothelial cells to increased shear stress?
Activation of eNOS and NO production
Inhibition of cell migration
Reduction in cell adhesion
Stimulation of VEGF production
Explanation - Shear stress activates eNOS, increasing NO and promoting vessel dilation and alignment.
Correct answer is: Activation of eNOS and NO production
Q.133 Which of the following is a primary function of the protein TIE2 during angiogenesis?
It acts as a VEGF receptor
It regulates endothelial cell junctions
It serves as a receptor for angiopoietins
It degrades extracellular matrix
Explanation - TIE2 is activated by angiopoietin-1 or -2, influencing vessel maturation and stability.
Correct answer is: It serves as a receptor for angiopoietins
Q.134 Which of the following best describes the effect of anti-VEGF antibodies on tumor growth?
They accelerate tumor vascularization
They block VEGF, reducing tumor angiogenesis
They increase VEGF production
They stimulate endothelial proliferation
Explanation - Anti-VEGF therapies prevent VEGF from activating its receptors, limiting vessel growth in tumors.
Correct answer is: They block VEGF, reducing tumor angiogenesis
Q.135 Which of the following molecules is a key mediator of endothelial cell migration during angiogenesis?
MMP-9
TGF-β
PDGF
EGF
Explanation - MMP-9 degrades ECM, allowing endothelial cells to migrate toward VEGF gradients.
Correct answer is: MMP-9
Q.136 Which of the following is a key component of the extracellular matrix that facilitates endothelial cell migration?
Collagen I
Elastin
Fibronectin
Keratin
Explanation - Fibronectin binds integrins, guiding endothelial cells during sprouting.
Correct answer is: Fibronectin
Q.137 Which of the following best describes the function of platelet-derived growth factor-BB (PDGF-BB) during vessel maturation?
It promotes endothelial proliferation
It recruits smooth muscle cells to the vessel wall
It inhibits VEGF signaling
It stimulates pericyte apoptosis
Explanation - PDGF-BB signals smooth muscle cells to migrate and differentiate around new vessels.
Correct answer is: It recruits smooth muscle cells to the vessel wall
Q.138 Which of the following is a key anti-angiogenic protein secreted by endothelial cells?
Angiopoietin-1
Thrombospondin-1
VEGF
PDGF
Explanation - Thrombospondin-1 binds to endothelial receptors and inhibits migration and proliferation.
Correct answer is: Thrombospondin-1
Q.139 Which of the following is the most common method used to quantify microvessel density in tissue sections?
ELISA for VEGF
Immunohistochemistry for CD31
Western blot for eNOS
Flow cytometry for CD34
Explanation - CD31 staining visualizes endothelial cells, enabling microvessel count.
Correct answer is: Immunohistochemistry for CD31
Q.140 Which of the following best describes the role of the Notch signaling pathway in angiogenesis?
It stimulates endothelial cell migration
It regulates tip/stalk cell selection during sprouting
It inhibits smooth muscle recruitment
It is unrelated to vascular development
Explanation - Notch signaling determines which endothelial cells become tip or stalk cells.
Correct answer is: It regulates tip/stalk cell selection during sprouting
Q.141 Which of the following molecules is secreted by macrophages to promote endothelial cell proliferation?
VEGF
IL-1β
TNF-α
IL-10
Explanation - Macrophage-derived VEGF stimulates endothelial proliferation during angiogenesis.
Correct answer is: VEGF
Q.142 Which of the following best describes the effect of increased pericyte coverage on vascular permeability?
It increases permeability
It decreases permeability
It has no effect
It reduces endothelial cell proliferation
Explanation - Pericyte coverage tightens junctions and reduces leakiness.
Correct answer is: It decreases permeability
Q.143 Which of the following best explains why collagen-based scaffolds are often used in tissue engineering?
They are electrically conductive
They provide natural binding sites for cell adhesion
They are highly hydrophobic
They prevent angiogenesis
Explanation - Collagen contains RGD motifs that facilitate endothelial adhesion and migration.
Correct answer is: They provide natural binding sites for cell adhesion
Q.144 Which of the following molecules is a key regulator of endothelial cell proliferation during angiogenesis?
VEGF
Thrombospondin-1
Angiostatin
Endostatin
Explanation - VEGF stimulates endothelial proliferation via VEGFR2 activation.
Correct answer is: VEGF
Q.145 Which of the following best describes the role of the extracellular matrix protein laminin in angiogenesis?
It inhibits endothelial cell adhesion
It promotes endothelial cell migration by binding integrins
It acts as a growth factor
It degrades the basement membrane
Explanation - Laminin interacts with endothelial integrins, facilitating migration through the matrix.
Correct answer is: It promotes endothelial cell migration by binding integrins
Q.146 Which of the following is a key feature of a sprouting endothelial tip cell?
High expression of VEGFR1
High filopodia number
Low proliferation rate
Pericyte coverage
Explanation - Tip cells extend numerous filopodia to sense VEGF gradients during sprouting.
Correct answer is: High filopodia number
Q.147 Which of the following best explains the role of MMP-2 during angiogenesis?
It promotes endothelial cell adhesion
It degrades the extracellular matrix to allow migration
It inhibits VEGF signaling
It stimulates smooth muscle cell proliferation
Explanation - MMP-2 cleaves matrix components, creating pathways for endothelial cells.
Correct answer is: It degrades the extracellular matrix to allow migration
Q.148 Which of the following best describes the process of arteriogenesis?
Formation of new capillaries from progenitor cells
Growth and remodeling of existing collateral vessels
Sprouting of endothelial cells from existing vessels
Formation of new veins from arteries
Explanation - Arteriogenesis enlarges pre-existing collateral vessels to improve blood flow.
Correct answer is: Growth and remodeling of existing collateral vessels
Q.149 Which of the following is a key factor that inhibits endothelial cell migration and proliferation?
VEGF
FGF-2
Thrombospondin-1
PDGF
Explanation - Thrombospondin-1 blocks VEGF signaling and reduces endothelial activity.
Correct answer is: Thrombospondin-1
Q.150 Which of the following best describes the role of integrin αvβ3 in angiogenesis?
It inhibits endothelial migration
It promotes endothelial migration and survival
It binds VEGF directly
It degrades extracellular matrix
Explanation - αvβ3 integrin activates signaling pathways that support angiogenic processes.
Correct answer is: It promotes endothelial migration and survival
Q.151 Which of the following is a key characteristic of a mature vessel?
High endothelial permeability
Presence of smooth muscle cells
Absence of pericytes
Single layer of endothelial cells with no basement membrane
Explanation - Mature vessels have smooth muscle cells and pericytes, providing structural stability.
Correct answer is: Presence of smooth muscle cells
Q.152 Which of the following is a main function of the protein TIE2 during vessel maturation?
It binds VEGF
It promotes pericyte recruitment
It inhibits endothelial cell migration
It degrades extracellular matrix
Explanation - TIE2 activation by angiopoietin-1 signals pericyte association and vessel stabilization.
Correct answer is: It promotes pericyte recruitment
Q.153 Which of the following best describes the role of VEGF in angiogenesis?
It inhibits endothelial cell proliferation
It stimulates endothelial cell migration and proliferation
It promotes pericyte apoptosis
It blocks MMP activity
Explanation - VEGF activates VEGFR2, promoting endothelial functions essential for new vessel formation.
Correct answer is: It stimulates endothelial cell migration and proliferation
Q.154 Which of the following is a key role of matrix metalloproteinase-9 (MMP-9) during vessel sprouting?
It promotes endothelial proliferation
It degrades extracellular matrix
It inhibits VEGF secretion
It stimulates pericyte adhesion
Explanation - MMP-9 breaks down ECM, allowing endothelial cells to migrate and form sprouts.
Correct answer is: It degrades extracellular matrix
Q.155 Which of the following best explains how pericytes contribute to vessel maturation?
They secrete VEGF to promote endothelial growth
They provide structural support and reduce permeability
They recruit immune cells to the wound
They degrade the basement membrane
Explanation - Pericytes wrap around endothelial cells, stabilizing vessels and limiting leakage.
Correct answer is: They provide structural support and reduce permeability
Q.156 Which of the following is a key component of the extracellular matrix that promotes endothelial cell adhesion during angiogenesis?
Collagen I
Fibronectin
Elastin
Keratin
Explanation - Fibronectin binds integrins on endothelial cells, aiding migration and sprouting.
Correct answer is: Fibronectin
Q.157 Which of the following best describes the role of shear stress in endothelial cell function?
It has no effect on endothelial cells
It inhibits eNOS activation
It promotes eNOS activation and NO production
It reduces cell adhesion
Explanation - Shear stress stimulates eNOS, increasing nitric oxide and influencing vessel behavior.
Correct answer is: It promotes eNOS activation and NO production
Q.158 Which of the following best explains why angiogenesis is important for tissue regeneration?
It reduces oxygen supply to tissues
It supplies nutrients and oxygen to growing tissues
It inhibits cell proliferation
It increases apoptosis
Explanation - New blood vessels provide the necessary resources for regenerating tissues.
Correct answer is: It supplies nutrients and oxygen to growing tissues
Q.159 Which of the following best describes the main function of the basement membrane during angiogenic sprouting?
It prevents endothelial cell adhesion
It acts as a physical barrier to migration
It provides a scaffold for endothelial cell migration
It blocks VEGF signaling
Explanation - The basement membrane is remodeled to allow endothelial cells to migrate toward VEGF gradients.
Correct answer is: It provides a scaffold for endothelial cell migration
Q.160 Which of the following is a hallmark of the inflammatory phase of wound healing?
Collagen deposition
Granulation tissue formation
Macrophage infiltration and cytokine release
Smooth muscle cell proliferation
Explanation - Macrophages secrete cytokines like VEGF to initiate angiogenesis during inflammation.
Correct answer is: Macrophage infiltration and cytokine release
Q.161 Which of the following is a key factor that promotes endothelial cell proliferation during angiogenesis?
Thrombospondin-1
VEGF
Angiostatin
Endostatin
Explanation - VEGF is a potent mitogen for endothelial cells via VEGFR2.
Correct answer is: VEGF
Q.162 Which of the following best describes the function of pericytes in mature vessels?
They stimulate endothelial apoptosis
They provide structural support and regulate permeability
They secrete growth factors for endothelial cells
They form the basement membrane
Explanation - Pericytes wrap around endothelial cells and maintain vessel stability and barrier function.
Correct answer is: They provide structural support and regulate permeability
Q.163 Which of the following is a common therapeutic strategy to enhance angiogenesis in ischemic tissues?
Administration of anti-VEGF antibodies
Local delivery of VEGF
Inhibition of endothelial cell migration
Inhibition of MMP activity
Explanation - Delivering VEGF locally increases angiogenic signaling and promotes vessel growth in ischemic areas.
Correct answer is: Local delivery of VEGF
Q.164 Which of the following best describes the role of integrin αvβ3 in endothelial cell migration?
It inhibits migration by blocking integrin signaling
It promotes migration by binding ECM and activating signaling pathways
It degrades extracellular matrix
It sequesters VEGF
Explanation - αvβ3 integrin interacts with fibronectin and other ECM proteins to support cell movement.
Correct answer is: It promotes migration by binding ECM and activating signaling pathways
Q.165 Which of the following is a key mechanism by which macrophages contribute to angiogenesis?
They secrete VEGF and other growth factors
They inhibit endothelial proliferation
They form the basement membrane
They degrade collagen
Explanation - Macrophages release VEGF and cytokines that stimulate endothelial cell activity.
Correct answer is: They secrete VEGF and other growth factors
Q.166 Which of the following is a hallmark of mature, functional capillaries?
High permeability
Presence of pericytes
Large diameter
Absence of basement membrane
Explanation - Pericytes wrap around capillaries, reducing permeability and providing stability.
Correct answer is: Presence of pericytes
Q.167 Which of the following molecules is a key regulator of angiogenesis and can act as an inhibitor when overexpressed?
VEGF
Endostatin
FGF-2
PDGF
Explanation - Endostatin inhibits VEGF signaling and can reduce angiogenesis if overproduced.
Correct answer is: Endostatin
Q.168 Which of the following is a key function of MMP-9 during angiogenesis?
It inhibits endothelial proliferation
It promotes endothelial migration by degrading ECM
It blocks VEGF secretion
It stimulates pericyte apoptosis
Explanation - MMP-9 cleaves extracellular matrix components, allowing endothelial cells to move toward VEGF.
Correct answer is: It promotes endothelial migration by degrading ECM
Q.169 Which of the following best describes the process by which endothelial cells sense and migrate toward VEGF gradients?
VEGF is internalized and stored
VEGF receptors on the cell surface detect concentration differences
VEGF is secreted by other cells
VEGF binds to integrins
Explanation - Endothelial cells use VEGFR2 to sense VEGF concentration and direct migration.
Correct answer is: VEGF receptors on the cell surface detect concentration differences
Q.170 Which of the following is a key mediator secreted by endothelial cells that can attract pericytes?
Angiopoietin-1
Angiopoietin-2
VEGF
PDGF-BB
Explanation - Angiopoietin-1 binds to TIE2 on pericytes, promoting their recruitment.
Correct answer is: Angiopoietin-1
Q.171 Which of the following best describes the role of VEGF in early angiogenesis?
It inhibits endothelial proliferation
It stimulates endothelial migration and proliferation
It blocks VEGFR activation
It reduces nitric oxide production
Explanation - VEGF signals through VEGFR2 to activate endothelial cells during vessel sprouting.
Correct answer is: It stimulates endothelial migration and proliferation
Q.172 Which of the following best explains why angiogenesis is important for wound healing?
It supplies oxygen and nutrients to the regenerating tissue
It increases apoptosis
It decreases collagen synthesis
It blocks immune cell infiltration
Explanation - New vessels bring necessary resources for cell proliferation and tissue repair.
Correct answer is: It supplies oxygen and nutrients to the regenerating tissue
Q.173 Which of the following is a key role of integrins in endothelial cells?
They act as growth factor receptors
They mediate cell-ECM adhesion and signal transduction
They degrade the basement membrane
They inhibit VEGF binding
Explanation - Integrins link the cytoskeleton to the extracellular matrix and activate signaling pathways.
Correct answer is: They mediate cell-ECM adhesion and signal transduction
Q.174 Which of the following best describes the role of the Notch signaling pathway during angiogenesis?
It promotes endothelial cell migration
It regulates tip/stalk cell selection
It inhibits smooth muscle recruitment
It is unrelated to blood vessel formation
Explanation - Notch signaling determines which endothelial cells become tip or stalk cells during sprouting.
Correct answer is: It regulates tip/stalk cell selection
Q.175 Which of the following best explains the function of the basement membrane during endothelial sprouting?
It acts as a barrier preventing migration
It provides structural support and guidance for migrating cells
It inhibits growth factor release
It degrades ECM
Explanation - The basement membrane is remodeled to allow endothelial cells to navigate toward VEGF signals.
Correct answer is: It provides structural support and guidance for migrating cells
Q.176 Which of the following is a characteristic of a mature vessel?
High endothelial permeability
Presence of pericytes
Absence of smooth muscle cells
Large lumen diameter without support
Explanation - Mature vessels have pericytes that stabilize the structure and reduce permeability.
Correct answer is: Presence of pericytes
Q.177 Which of the following best describes the role of TIE2 in angiogenesis?
It is a VEGF receptor
It mediates the response to angiopoietin-1 and -2
It degrades extracellular matrix
It is an integrin
Explanation - TIE2 is activated by angiopoietins, influencing vessel maturation and stability.
Correct answer is: It mediates the response to angiopoietin-1 and -2
Q.178 Which of the following best explains the effect of anti-VEGF therapy in cancer treatment?
It stimulates new vessel formation
It blocks VEGF, reducing tumor angiogenesis
It increases VEGF secretion
It enhances endothelial migration
Explanation - Anti-VEGF antibodies bind VEGF, preventing it from activating endothelial receptors.
Correct answer is: It blocks VEGF, reducing tumor angiogenesis
Q.179 Which of the following best describes the role of MMP-9 during vessel sprouting?
It promotes endothelial cell proliferation
It degrades the extracellular matrix
It inhibits VEGF secretion
It promotes smooth muscle cell recruitment
Explanation - MMP-9 cleaves ECM components, facilitating endothelial cell migration.
Correct answer is: It degrades the extracellular matrix
Q.180 Which of the following is a key factor that promotes endothelial cell migration?
Thrombospondin-1
VEGF
Angiostatin
Endostatin
Explanation - VEGF signals through its receptor to drive endothelial migration and sprouting.
Correct answer is: VEGF
Q.181 Which of the following best explains why angiogenesis is important during tissue regeneration?
It reduces oxygen supply to tissues
It supplies nutrients and oxygen to the growing tissue
It inhibits cell proliferation
It promotes apoptosis
Explanation - New vessels provide necessary resources for regenerating tissues.
Correct answer is: It supplies nutrients and oxygen to the growing tissue
Q.182 Which of the following best describes the function of pericytes in vascular stability?
They inhibit endothelial proliferation
They provide structural support and reduce permeability
They secrete VEGF
They degrade extracellular matrix
Explanation - Pericytes attach to endothelial cells and stabilize vessels.
Correct answer is: They provide structural support and reduce permeability
Q.183 Which of the following best explains how endothelial cells sense and migrate toward VEGF gradients?
VEGF is internalized and stored
VEGF receptors detect concentration differences
VEGF is secreted by other cells
VEGF binds to integrins
Explanation - Endothelial cells use VEGFR2 to detect VEGF concentration and direct migration.
Correct answer is: VEGF receptors detect concentration differences
Q.184 Which of the following best describes the role of the basement membrane during angiogenic sprouting?
It prevents endothelial migration
It serves as a scaffold for migration
It inhibits VEGF signaling
It degrades ECM
Explanation - The basement membrane is remodeled to allow endothelial cells to migrate toward VEGF gradients.
Correct answer is: It serves as a scaffold for migration
Q.185 Which of the following is a hallmark of the inflammatory phase of wound healing?
Collagen deposition
Granulation tissue formation
Macrophage infiltration and cytokine release
Smooth muscle cell proliferation
Explanation - Macrophages release cytokines like VEGF that initiate angiogenesis during inflammation.
Correct answer is: Macrophage infiltration and cytokine release
Q.186 Which of the following best describes the role of VEGF in angiogenesis?
Inhibits endothelial cell proliferation
Stimulates endothelial migration and proliferation
Promotes pericyte apoptosis
Blocks MMP activity
Explanation - VEGF activates VEGFR2, promoting endothelial functions essential for new vessel formation.
Correct answer is: Stimulates endothelial migration and proliferation
Q.187 Which of the following best describes the function of pericytes in mature vessels?
They stimulate endothelial apoptosis
They provide structural support and regulate permeability
They secrete growth factors for endothelial cells
They form the basement membrane
Explanation - Pericytes wrap around endothelial cells and maintain vessel stability and barrier function.
Correct answer is: They provide structural support and regulate permeability
Q.188 Which of the following is a common therapeutic strategy to enhance angiogenesis in ischemic tissues?
Administration of anti-VEGF antibodies
Local delivery of VEGF
Inhibition of endothelial cell migration
Inhibition of MMP activity
Explanation - Delivering VEGF locally increases angiogenic signaling and promotes vessel growth in ischemic areas.
Correct answer is: Local delivery of VEGF
Q.189 Which of the following best describes the role of integrin αvβ3 in endothelial cell migration?
It inhibits migration by blocking integrin signaling
It promotes migration by binding ECM and activating signaling pathways
It degrades extracellular matrix
It sequesters VEGF
Explanation - αvβ3 integrin interacts with fibronectin and other ECM proteins to support cell movement.
Correct answer is: It promotes migration by binding ECM and activating signaling pathways
Q.190 Which of the following is a key mechanism by which macrophages contribute to angiogenesis?
They secrete VEGF and other growth factors
They inhibit endothelial proliferation
They form the basement membrane
They degrade collagen
Explanation - Macrophages release VEGF and cytokines that stimulate endothelial cell activity.
Correct answer is: They secrete VEGF and other growth factors
Q.191 Which of the following is a hallmark of mature, functional capillaries?
High permeability
Presence of pericytes
Large diameter
Absence of basement membrane
Explanation - Pericytes wrap around capillaries, reducing permeability and providing stability.
Correct answer is: Presence of pericytes
Q.192 Which of the following molecules is a key regulator of angiogenesis and can act as an inhibitor when overexpressed?
VEGF
Endostatin
FGF-2
PDGF
Explanation - Endostatin inhibits VEGF signaling and can reduce angiogenesis if overproduced.
Correct answer is: Endostatin
Q.193 Which of the following is a key function of MMP-9 during vessel sprouting?
It inhibits endothelial proliferation
It promotes endothelial migration by degrading ECM
It blocks VEGF secretion
It stimulates pericyte apoptosis
Explanation - MMP-9 cleaves extracellular matrix components, allowing endothelial cells to move toward VEGF.
Correct answer is: It promotes endothelial migration by degrading ECM
Q.194 Which of the following best describes how endothelial cells sense and migrate toward VEGF gradients?
VEGF is internalized and stored
VEGF receptors detect concentration differences
VEGF is secreted by other cells
VEGF binds to integrins
Explanation - Endothelial cells use VEGFR2 to detect VEGF concentration and direct migration.
Correct answer is: VEGF receptors detect concentration differences
Q.195 Which of the following best describes the function of the basement membrane during angiogenic sprouting?
It prevents endothelial migration
It serves as a scaffold for migration
It inhibits VEGF signaling
It degrades ECM
Explanation - The basement membrane is remodeled to allow endothelial cells to migrate toward VEGF gradients.
Correct answer is: It serves as a scaffold for migration
Q.196 Which of the following is a hallmark of the inflammatory phase of wound healing?
Collagen deposition
Granulation tissue formation
Macrophage infiltration and cytokine release
Smooth muscle cell proliferation
Explanation - Macrophages release cytokines like VEGF that initiate angiogenesis during inflammation.
Correct answer is: Macrophage infiltration and cytokine release
Q.197 Which of the following best describes the role of VEGF in angiogenesis?
Inhibits endothelial cell proliferation
Stimulates endothelial migration and proliferation
Promotes pericyte apoptosis
Blocks MMP activity
Explanation - VEGF activates VEGFR2, promoting endothelial functions essential for new vessel formation.
Correct answer is: Stimulates endothelial migration and proliferation
Q.198 Which of the following best describes the function of pericytes in mature vessels?
They stimulate endothelial apoptosis
They provide structural support and regulate permeability
They secrete growth factors for endothelial cells
They form the basement membrane
Explanation - Pericytes wrap around endothelial cells and maintain vessel stability and barrier function.
Correct answer is: They provide structural support and regulate permeability
Q.199 Which of the following is a common therapeutic strategy to enhance angiogenesis in ischemic tissues?
Administration of anti-VEGF antibodies
Local delivery of VEGF
Inhibition of endothelial cell migration
Inhibition of MMP activity
Explanation - Delivering VEGF locally increases angiogenic signaling and promotes vessel growth in ischemic areas.
Correct answer is: Local delivery of VEGF
Q.200 Which of the following best describes the role of integrin αvβ3 in endothelial cell migration?
It inhibits migration by blocking integrin signaling
It promotes migration by binding ECM and activating signaling pathways
It degrades extracellular matrix
It sequesters VEGF
Explanation - αvβ3 integrin interacts with fibronectin and other ECM proteins to support cell movement.
Correct answer is: It promotes migration by binding ECM and activating signaling pathways