What are mesangial cells in glomerulus?
Mesangial cells are smooth muscle–like cells that contain actin and myosin; they connect to each other via gap junctions and to the GBM via cell processes. Contraction of mesangial cells regulates the size of the capillary lumen and thus the amount of glomerular blood flow.
What is the function of the mesangial cells?
Mesangial cells lie close to the capillary lumen and play an important role in glomerular hemodynamics and immune complex clearance. The mesangial cells produce a matrix made up of collagen, fibronectin, and proteglycans that supports the glomerular capillaries.
How do the mesangial cells help regulate the glomerular filtration rate?
The rate of renal filtration is in large part responsible for volume and electrolyte balance in an organism. Integral components of the renal glomerulus are the mesangial cells (MCs), excitable renal pericytes that regulate the glomerular filtration rate by modulating the surface area of the capillaries.
What do mesangial cells secrete?
Mesangial cells are also specialized cells and have many important functions. They secrete an extracellular matrix substance (mesangial matrix) rich in laminin and fibronectin that helps support the capillary tuft. Some mesangial cells contain actomyosin filaments and are contractile.
What is mesangial matrix?
Mesangial matrix provides structural support for the mesangium. Mesangial matrix is composed of glomerular matrix proteins such as collagen IV (α1 and α2 chains), collagen V, collagen VI, lamininA, B1, B2, fibronectin, and proteoglycans.
What is the mesangial matrix?
What is mesangial cell proliferation?
Mesangial cell (MC) proliferation is a key pathological feature in a number of common human renal diseases including IgA, systemic lupus erythematosus and diabetic nephropathies. Unfortunately, despite these advances, there are still very few clinical options that specifically target aberrant MC proliferation.
What happens when glomerular mesangial cells contract?
Contraction of mesangial cells is coupled with contraction of the basement membrane of the endothelium of glomerular capillaries. This causes a decrease in surface area of the basement membrane and thus a decreased glomerular filtration rate.
Why do mesangial cells proliferate?
Aberrant proliferation of mesangial cells (MCs) is a common finding in a number of diseases that can lead to end-stage renal failure. A variety of initial insults, which may be metabolic (as in diabetic nephropathy), or immunological (as in IgA disease and lupus nephritis), can cause uncontrolled MC proliferation.
Is renin a vasoconstrictor?
It acts directly on vascular smooth muscle as a potent vasoconstrictor. In addition, it affects cardiac contractility and heart rate through its action on the sympathetic nervous system.