A Road to Chronic Kidney Disease

Effects of excessive sodium chloride loading in the spontaneously diabetic torii (SDT) fatty rats, a preclinical model of type 2 diabetes mellitus

Type 2 diabetes mellitus represents an international health concern with its growing number of patients worldwide. At the same time, excessive salt consumption is also seen as a major cause of diseases such as hypertension and may expedite renal complications in diabetic patients. In this study, we investigated the effects of excessive sodium chloride supplementation on the kidney of the Spontaneously Diabetic Torii-Lepr^fa (SDT fatty) rat, an obese type 2 diabetes model. Male and female SDT fatty rats and normal Sprague-Dawley (SD) rats at 5 weeks of age were loaded with 0.3% sodium chloride (NaCl) in drinking water for 13 weeks. Blood serum and urinary parameters were observed throughout the experiment and kidney samples were examined in histopathological and genetical analyses. Significant changes on the body weight, blood pressure, urine volume, creatinine clearance, blood urea nitrogen (BUN), relative gene expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1) and transforming growth factor-β (TGF-β) were observed in the salt-loaded male SDT fatty rats. Urinary L-type fatty acid-binding protein (L-FABP) and albumin levels were higher observed in the salt-loaded male SDT fatty rats throughout the period, but urinary albumin levels in the female SDT fatty rats remain unchanged. In the kidney, slight Armani-Ebstein changes, tubular degeneration, hyaline cast, and inflammatory cell infiltration were observed in female SDT fatty rats while the levels of some changes were higher in the salt-loaded group. The kidney of the salt-loaded male SDT fatty rats demonstrated a higher degree of lesions compared to the female group and the male unloaded group. Histopathological changes in salt-loaded SDT fatty rats show that excessive salt consumption may act as a diabetic pathology exacerbation factor, but the pathology may be influenced by gender difference. Urinary L-FABP levels may act as a useful biomarker to detect slight tubular damages in the kidney. Excessive salt loading was shown to exacerbate the renal injury in SDT fatty rats.

Expression of DENDRIN in several glomerular diseases and correlation to pathological parameters and renal failure - preliminary study

Background

In glomerular injury dendrin translocates from the slit diaphragm to the podocyte nucleus, inducing apoptosis. We analyzed dendrin expression in IgA glomerulonephritis and Henoch Schönlein purpura (IgAN/HSP) versus in podocytopathies minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS), and compared it to pathohistological findings and renal function at the time of biopsy and the last follow-up.

Methods

Twenty males and 13 females with median of age 35 years (min-max: 3–76) who underwent percutaneous renal biopsy and had diagnosis of glomerular disease (GD) were included in this retrospective study. Fifteen patients had IgAN/HSP and eighteen podocytopathy. Control group consisted of ten patients who underwent nephrectomy due to renal cancer. Dendrin expression pattern (membranous, dual, nuclear or negative), number of dendrin positive nuclei and proportion of dendrin negative glomeruli were analyzed.

Results

In GD and the control group significant differences in number of dendrin positive nuclei and proportion of dendrin negative glomeruli were found (P = 0.004 and P = 0.003, respectively). Number of dendrin positive nuclei was higher in podocytopathies than in IgAN/HSP, 3.90 versus 1.67 (P = 0.028). Proportion of dendrin negative glomeruli correlated to higher rates of interstitial fibrosis (P = 0.038), tubular atrophy (P = 0.011) and globally sclerotic glomeruli (P = 0.008). Dual and nuclear dendrin expression pattern were connected with lower rate of interstitial fibrosis and tubular atrophy than negative dendrin expression pattern (P = 0.024 and P = 0.017, respectively). Proportion of dendrin negative glomeruli correlated with lower creatinine clearance (CC) at the time of biopsy and the last follow-up (P = 0.010 and P < 0.001, respectively). Dendrin expression pattern correlated to CC at the last follow-up (P = 0.009), being lower in patients with negative than nuclear or dual dendrin expression (P = 0.034 and P = 0.004, respectively).

Conclusion

In this pilot study the number of dendrin positive nuclei was higher in podocytopathies than in inflammatory GD. Negative dendrin expression pattern correlated to chronic tubulointerstitial changes and lower CC, which needs to be confirmed in a larger series.