Myofibroblasts in Fibrotic Kidneys

Fibrosis of the kidney glomerulus and interstitium are characteristic features of almost all chronic kidney diseases. Fibrosis is tightly associated with destruction of capillaries, inflammation, and epithelial injury which progresses to loss of nephrons, and replacement of kidney parenchyma with scar tissue. Understanding the origins and nature of the cells known as myofibroblasts that make scar tissue is central to development of new therapeutics for kidney disease. Whereas many cell lineages in the body have become defined by well-established markers, myofibroblasts have been much harder to identify with certainty. Recent insights from genetic fate mapping and the use of dynamic reporting of cells that make fibrillar collagen in mice have identified with greater clarity the major population of myofibroblasts and their precursors in the kidney. This review will explore the nature of these cells in health and disease of the kidney to understand their central role in the pathogenesis of kidney disease.