Glomerular cell number in normal subjects and in type 1 diabetic patients

Steffes, Michael W.; Schmidt, D. W.; McCrery, Rebecca; Basgen, John M.; Group, International Diabetic Nephropathy Study

doi:10.1046/j.1523-1755.2001.0590062104.x

Cited by 68 publications

(81 citation statements)

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“…Previous studies have demonstrated that the decrease in podocyte number is a critical determinant contributing to the development of glomerulosclerosis in diabetic and non-diabetic glomerular diseases [3, 20, 21]. In the current study we show that podocytes detaching from the glomerular basement membrane and shed into the urinary space in experimental diabetic nephropathy adhere to tissue culture plates ex vivo, proliferate, and undergo morphological changes.…”

Section: Discussionsupporting

confidence: 65%

Viable Podocytes Detach in Experimental Diabetic Nephropathy: Potential Mechanism Underlying Glomerulosclerosis

Petermann

Pippin

Krofft

et al. 2004

Nephron Exp Nephrol

116

101

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Background: A decrease in podocyte number contributes to the development of glomerulosclerosis in diabetic nephropathy. Although podocytes have been detected in the urine in certain glomerular diseases, their viability is poorly understood. Methods: Diabetes was induced in rats with streptozotocin. Urine was collected from control rats (given citrate), and rats with diabetic nephropathy, and cells obtained by centrifugation were resuspended in tissue culture media, and seeded onto collagen-coated tissue culture plates. Cells were grown under standard cell culture conditions ex vivo. Cell number was measured, the cell type in the urine was identified by immunostaining with specific antibodies, and morphology was assessed by light and electron microscopy. Results: Within 24 h, cells obtained from the urine of diabetic rats attached to tissue culture plates ex vivo. Cells were not detected in the urine from control rats. All cells from diabetic rats stained positive for the podocyte-specific proteins synaptopodin, nephrin, podocin and Glepp-1 and negative for mesangial (OX-7), tubular (Tamm-Horsfall protein) and endothelial (RECA) cell antigens. The cell number increased daily, which is consistent with cell growth ex vivo. Conclusions: Rats with diabetic nephropathy shed podocytes into the urine that attach and grow ex vivo. These results are consistent with the detachment of viable podocytes in diabetes and add new perspectives into our understanding of development of glomerulosclerosis in diabetes mellitus.

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Section: Discussionsupporting

confidence: 65%

Viable Podocytes Detach in Experimental Diabetic Nephropathy: Potential Mechanism Underlying Glomerulosclerosis

Petermann

Pippin

Krofft

et al. 2004

Nephron Exp Nephrol

116

101

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“…Sclerosing glomeruli are characterized by progressive depletion of podocytes, resulting in denuded glomerular basement membrane areas and tuft adhesions, which may be considered as initial lesions of irreversible glomerular injury (4,7). Indeed, recent studies demonstrate that podocyte numbers are reduced early in glomeruli of diabetic patients with nephropathy (8,9). We have shown that TGF-␤1 induces apoptosis in podocytes in vitro and in vivo via a p38 MAPK and caspase-dependent mechanism.…”

mentioning

confidence: 80%

A Novel Role for the Adaptor Molecule CD2-associated Protein in Transforming Growth Factor-β-induced Apoptosis

Schiffer

Mündel

Shaw

et al. 2004

Journal of Biological Chemistry

185

203

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CD2-associated protein (CD2AP) is an adaptor molecule involved in T cell receptor signaling and podocyte homeostasis. CD2AP-deficient mice develop nephrotic syndrome and renal failure caused by glomerulosclerosis. Here we report that increased transforming growth factor-␤1 (TGF-␤1) expression and apoptosis were present in podocytes at the onset of albuminuria and were followed by depletion of podocytes associated with progressive focal-segmental glomerulosclerosis in CD2AP؊/؊ mice. Conditionally immortalized podocytes derived from CD2AP؊/؊ mice were more susceptible to TGF-␤-induced apoptosis compared with CD2AP؉/؉ podocytes. Reconstitution of CD2AP rescued CD2AP؊/؊ podocytes from TGF-␤-induced apoptosis. CD2AP was required for early activation of anti-apoptotic phosphatidylinositol 3-kinase (PI3K)/AKT and extracellular signal-regulated kinase 1/2 by TGF-␤. In contrast, activation of pro-apoptotic p38 MAPK by TGF-␤ was accelerated and enhanced in the absence of CD2AP. CD2AP was not required for PI3K/AKT activation by insulin and epidermal growth factor, indicating that CD2AP is a selective mediator of anti-apoptotic TGF-␤ signaling. In summary, we identified CD2AP as a novel mediator for selective activation of survival pathways and repression of apoptosis signaling by TGF-␤ in podocytes. Together, our in vitro and in vivo findings suggest that TGF-␤-induced podocyte apoptosis is an early pathomechanism in mice developing focal-segmental glomerulosclerosis associated with functional impairment of CD2AP.The transforming growth factor-␤ (TGF-␤) 1 superfamily consists of secreted peptides, of which the three TGF-␤ isoforms (TGF-␤1-3), activins, and bone morphogenetic proteins are best known in mammalian development, homeostasis, and pathobiology. The TGF-␤ isoforms are widely expressed and act on virtually every cell type in mammals by engaging a ubiquitous intracellular signaling cascade of Smad family proteins through ligand-induced activation of heteromeric transmembrane TGF-␤ receptor kinases. Receptor-activated Smad protein complexes accumulate in the nucleus where they participate directly in transcriptional activation of target genes. In addition, TGF-␤ receptors can activate Smad-independent signaling mechanisms, including mitogen-activated protein kinases (MAPKs), and PI3K (1, 2). However, molecular mechanisms of activation of Smad-independent pathways by TGF-␤ receptors remain unclear.The mouse CD2 receptor-associated protein (CD2AP) and its human orthologue Cas ligand with multiple SH3 domains (CMS) belong to a family of ubiquitously expressed adaptor molecules that also includes the human Cbl-interacting protein of 85 kDa (CIN85) and its rat and mouse orthologue regulator of ubiquitous kinase (Ruk) and SH3 domain-containing gene expressed in tumorigenic astrocytes (SETA) (for review, see Ref.3). These proteins are defined as cytoplasmic adaptor or scaffolding proteins by three N-terminal SH3 domains, a proline-rich domain, and a C-terminal coiled-coil domain. CIN85/ CMS family proteins have been shown t...

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“…For this study 1.55 was used for β as previously described [13, 16]. Similar to the disector/fractionator method, images were obtained 5 µm apart from throughout each glomerulus, resulting in 13–19 sections per glomerulus.…”

Section: Methodsmentioning

confidence: 99%

“…Pagtalunan et al [2] used this method to count podocytes in diabetic Pima Indians. Since that publication, several other groups have used the Weibel-Gomez method to count the number of glomerular cells in patients with diabetes and other kidney diseases [14,15,16,17]. The disector/fractionator is a method of counting particles within a three-dimensional space independent of particle shape, size, or orientation [18,19,20].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Methods for Counting Cells in the Mouse Glomerulus

Basgen

Nicholas

Mauer

et al. 2006

Nephron Exp Nephrol

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Background: Researchers have long been interested in counting the number of cells within the glomerulus. Investigators using different techniques have yielded conflicting results. The most direct method is to count the cells in serial sections from the entire glomerulus. This Exhaustive Count method is not usually practical. The disector/fractionator method counts the number of cells in a fraction of sections. The total is estimated from the product of the cell count and the reciprocal of the fraction. The Weibel-Gomez method determines the density of cells per glomerulus, then multiplies this density by glomerular volume to obtain cell number. In this study, we compared the disector/fractionator and Weibel-Gomez methods to identify a practical alternative for the time-consuming Exhaustive Count method. Methods: Glomeruli from a normal mouse kidney were completely sectioned and images obtained. Appropriate images were used to count glomerular cell number using each method. Results: The Exhaustive Count method yielded 213 ± 22 (mean ± SD) cells/glomerulus vs. the disector/fractionator average of 211 ± 29 cells/glomerulus (p = 0.82). The Weibel-Gomez method average of 235 ± 26 cells/glomerulus was statistically different from the Exhaustive Count method (p = 0.003). Conclusion: The Weibel-Gomez produced a 10% overestimation, whereas the disector/fractionator method was unbiased and thus a good substitute for the Exhaustive Count method.

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Glomerular cell number in normal subjects and in type 1 diabetic patients

Cited by 68 publications

References 0 publications

Viable Podocytes Detach in Experimental Diabetic Nephropathy: Potential Mechanism Underlying Glomerulosclerosis

Viable Podocytes Detach in Experimental Diabetic Nephropathy: Potential Mechanism Underlying Glomerulosclerosis

A Novel Role for the Adaptor Molecule CD2-associated Protein in Transforming Growth Factor-β-induced Apoptosis

Comparison of Methods for Counting Cells in the Mouse Glomerulus

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