Detachment of podocytes from the glomerular basement membrane was not seen at any time point, and alterations in the glomerular basement membrane morphology were not observed

Detachment of podocytes from the glomerular basement membrane was not seen at any time point, and alterations in the glomerular basement membrane morphology were not observed. Open in a separate window Figure 3 Electron microscopy of podocytes in Dahl SS and SHR rats (A), and evaluation of the mean AQ-13 dihydrochloride foot process width (B). glomerular areas where podoplanin was lost. Dahl SS rats did not show podoplanin gene mutations or decreased mRNA expression. Thus, podocyte morphology and the expression and distribution of most podocyte-specific proteins were normal in young Dahl SS rats, despite marked proteinuria. Our study suggests that decreased expression of podoplanin plays a role in the decrease of glomerular permselectivity. The permselectivity of the glomerular filtration barrier restricts passage of proteins into Bowmans space. Loss of permselectivity leads to proteinuria, which is common in renal diseases of diverse origin. Proteinuria is related to the progression of renal and cardiovascular disease.1,2,3 Although the details of glomerular AQ-13 dihydrochloride filtration remain unknown, it is clear that the glomerular visceral epithelial cell or podocyte is an important component of the glomerular filtration barrier. Damage to podocytes is frequently involved in the pathogenesis of glomerular diseases. 4 Podocyte damage can be the result of changes in individual podocyte-associated proteins. Examples include mutations in the genes that encode nephrin, podocin, CD2AP, and -actinin-4.5,6,7,8 Such mutations can result in both congenital and hereditary forms of glomerular dysfunction. Podocyte damage also appears to be of pathogenic importance in acquired diseases. For example, in diabetic nephropathy and IgA nephropathy, podocyte loss is related to disease severity.9,10,11 Similarly, animal models have shown that loss of podocytes is related to the development of proteinuria and glomerulosclerosis.12,13,14,15 A change in podocyte morphology often accompanies proteinuria. In the normal glomerulus, the podocyte has an arborized phenotype, and its terminal branches or foot processes cover the outer wall of the glomerular capillaries. In proteinuric states, this morphology is typically lost as the podocyte converts to a flatter epithelial cell, a process referred to as foot process effacement. In foot process effacement, the cytoskeleton that normally supports the delicate architecture of the foot processes is condensed at the basal side of the flattened podocytes.16 We previously studied the mRNA and protein expression of several podocyte-associated proteins in acquired proteinuric diseases. 17 Based on the results of that study, we hypothesized that the changes in expression of podocyte proteins represented a compensatory reaction of the podocyte to the occurrence of proteinuria. Accordingly, we wanted to investigate how the expression of podocyte-associated proteins is regulated during the development of proteinuria, and how changes in expression are related to podocyte morphology. We studied proteins that have been shown to be SSI2 involved in congenital and hereditary nephrotic syndromes, as well as podocyte proteins that have been studied in animal models. Among these is the glycoprotein podoplanin, of which the expression was previously found to change in the puromycin aminonucleoside nephrosis model of the rat.18 Studying human kidney biopsy samples does not allow the rigorous evaluation of changes over time. In this study, we therefore used the Dahl salt-sensitive rat (Dahl SS) proteinuric model19 to evaluate changes in podocyte morphology and expression of podocyte-associated proteins during the advancement of proteinuria. Components and Methods Pets and Study Style We likened the spontaneously proteinuric Dahl SS rat stress with non-proteinuric spontaneous hypertensive (SHR) rats. Man Dahl SHR and SS rats were extracted from colonies on the Freie Universit? t Berlin as reported.19 All animals had been fed a low-salt diet plan containing 0.2% NaCl by fat; on this diet plan, Dahl SS rats develop light spontaneous hypertension much like SHR rats. To review adjustments in appearance AQ-13 dihydrochloride of podocyte-associated proteins through the advancement of proteinuria, sets of rats (= 5 to 8 rats AQ-13 dihydrochloride per group) had been examined at 2, 4, 6, 8, and 10 weeks old. Experiments had been performed relative to institutional guidelines. Bloodstream and Urinalysis Pressure Measurements Urinalysis was performed in each rat. Rats which were 4 weeks old or older had been put into metabolic cages for the 24-hour period. In the 2-week-old rats, a urine test was attained by bladder punction prior to the perfusion method described below. Urinary albumin excretion was dependant on enzyme-linked immunosorbent assay subsequently.20 Urinary proteins excretion prices were determined using the Bradford method. In rats of 6 weeks old or old, systolic blood circulation pressure was driven using the tail-cuff.