Related Experiment Video
Updated: Aug 23, 2026

Conditional Knockdown of Gene Expression in Cancer Cell Lines to Study the Recruitment of Monocytes/Macrophages to the Tumor Microenvironment
Published on: November 23, 2017
Plasminogen activator inhibitor 1, fibrin, and the vascular response to injury
1Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan, USA. wfay@umich.edu
Abstract:
Intravascular fibrin deposition is believed to play an important role in the development of intimal hyperplasia, which is a hallmark of several human vascular disorders, including atherosclerosis and restenosis after balloon angioplasty. Plasminogen activator inhibitor-1 (PAI-1), the primary inhibitor or tissue- and urinary-type plasminogen activator, plays a key role in fibrin homeostasis by controlling plasmin formation. PAI-1 may also modulate vascular pathology via alternative pathways, such as inhibiting activated protein C and altering interactions between vascular smooth muscle cells and the extracellular matrix. The diverse functional profile of PAI-1 likely accounts for the variation observed in its impact on intimal hyperplasia in different disease models. This review examines recent studies addressing the vascular function of PAI-1, and those assessing the role of fibrin as a downstream mediator of PAI-1's effects.
Related Concept Videos
Clot Retraction and Fibrinolysis
Introduction to Hemostasis
The three phases of hemostasis involve many clotting factors present in plasma and several substances released by platelets and injured tissue cells. It is a fast, localized, and...
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Extrinsic and Intrinsic Pathways of Hemostasis
The Extrinsic Pathway
The extrinsic pathway of coagulation is typically initiated by tissue damage that exposes blood to tissue factor (TF), a protein released by the damaged tissue cells outside the blood vessels—this interaction with TF triggers biochemical reactions involving specific clotting factors. The key player here is Factor VII, which forms a...
Vascular Spasm
Anticoagulant Drugs: Low-Molecular-Weight Heparins

