Abnormal glomerular mesangium morphology Abnormal glomerular mesangial matrix morphology 2020-10-31T12:50:08Z Any structural anomaly of the glomerular matrix. Mesangial cells generate and embed in their own extracellular matrix. The mesangial matrix is different in composition from the glomerular basement membrane. Its constituents are type IV collagen (but only the alpha1 and alpha2 chains); type V collagen; laminin A, B1, and B2; and considerable amounts of fibronectin, heparan sulfate and chondroitin sulfate proteoglycans, entactin, and nidogen. Furthermore, small amounts of the proteoglycans decorin and biglycan are found in the mesangial matrix.