Gender-related differences in kidney of rats with chronic renal failure.

Chronic renal failure is characterized by adaptive mechanisms secondary to the loss of functioning nephrons. Clinical and experimental studies suggest participation of gender-related hormones on renal function and progression of chronic renal failure. We evaluated the effect of castration on renal alterations in male and female Wistar control rats and after 30 days of chronic renal failure (CRF) induced by 5/6 nephrectomy. The CRF male group showed higher proteinuria. Glomerular hypertrophy was similar among groups. Podocyte morphology showed disorders of foot processes and thickening of the basement membrane in the CRF male group. The CRF female group showed fewer alterations compared to males. Castration changed the profile in CRF male animals and the filtration barrier was preserved. CRF males showed the presence of alfa-smooth muscle actin suggesting an early prefibrotic event in this group. After castration this phenomenon was not observed. Noteworthy, in females, castration exacerbated the presence of alfa-smooth muscle actin. In summary, proteinuria was higher in males and appeared early in the course of CRF, probably contributing to fibrotic events. Data were influenced by gender suggesting that male sex hormones aggravate renal alterations.

Body adiposity index assess body fat with high accuracy in nondialyzed chronic kidney disease patients.

OBJECTIVE: High body fat (BF) is an alarming condition that also affects nondialyzed chronic kidney disease (CKD) patients. Distinct methods are used to evaluate BF; however, in CKD population it remains unclear which one is more reliable showing high accuracy. Dual-energy X-ray absorptiometry (DXA), used as reference method to estimate adiposity, is expensive and time consuming to be applied in clinical settings. Recently, a new body adiposity index (BAI), that estimates BF from easily accessible measures, was validated in the general population. The aim of this study was to evaluate which simple and practical method, routinely used to estimate BF, shows the highest accuracy compared with DXA, in nondialyzed CKD patients. DESIGN AND METHODS: In this cross-sectional study BF was estimated by DXA, bioelectrical impedance analysis (BIA), anthropometry (ANTHRO), and BAI. Serum leptin levels were determined. RESULTS: Studied patients (n = 134) were 55% males, 54% overweight/obese, and 64.9 ± 12.5 years old, with estimated glomerular filtration rate (eGFR) = 29.0 ± 12.7 ml/min. The correlation coefficient was higher between DXA vs. ANTHRO (r = 0.76) and BAI (r = 0.61) than with BIA (r = 0.57), after adjusting for gender, age, and eGFR (P < 0.0001). Therefore, the Lin's concordance correlation coefficient and Bland-Altman plots were performed to measure the accuracy (C_b) between DXA with both ANTHRO and BAI. A higher accuracy (C_b = 0.82) and lower mean difference (-3.4%) was observed for BAI than for ANTHRO (C_b = 0.61; -8.4%). Leptin levels correlated (P < 0.0001) with DXA (r = 0.56) and BAI (r = 0.59). CONCLUSIONS: These findings suggest that BAI estimates BF with high accuracy in nondialyzed CKD patients and may be helpful in the treatment of this population with increased BF.

Is it possible to use modification of diet in renal disease (MDRD) equation in a Brazilian population?

BACKGROUND: Accurate assessment of kidney function level is the key to the identification and management of chronic kidney disease (CKD). Glomerular filtration rate (GFR) is the best measure of overall kidney function in health and disease. There is no consensus about the method to be used routinely to measure and/or estimate GFR. The objectives of this study were to assess which method correlates better with creatinine (Cr) clearance, extensively used in medical practice, as well as assessing the efficacy of the modification of diet in renal disease (MDRD) equation, in our population. METHODS: We studied 262 adult out-patients with stable CKD on conservative treatment. GFR was evaluated by Cr clearance, Cockcroft-Gault (CG) formula, the mean of urea and Cr clearances (total clearance (TCl)), the MDRD study equation, with and without the variable for African-Americans (MDRD1) and the simplified one (MDRDs). Data were analyzed by Pearson's correlation coefficient (r) and Bland & Altman plot analysis. RESULTS: Pearson's correlation showed that all methods where similar when compared to Cr clearance. A high correlation was observed between CG and MDRD equations, and TCl and MDRD equations showed the worst correlation. Among the MDRD equations, no differences were found. Bland-Altman plot analysis indicated a concordance among the studied methods. CONCLUSION: The CG formula could replace Cr clearance in our population, being simpler than and equally as sensitive as the MDRD equation.

Chronic renal failure in male and female rats.

Gender influences the progression of chronic renal failure (CRF). We studied male (M) and female (F) Wistar rats for 90 days: castrated (CMc,n=7;CFc,n=6) and non castrated controls (CM,n=9;CF,n=6); castrated (CRFMc,n=8; CRFFc,n=6) and non castrated animals submitted to 5/6 nephrectomy (CRFM,n=13;CRFF,n=6). Data are expressed as mean +/-SEM. Proteinuria (PTN) was higher in CRFM (554+/-69 mg/24h) compared to CRFMc (277+/-85 mg/24h), but not in females (CRFF=193+/-20mg/24h, CRFFc= 164+/-71 mg/24h). Mesangial fractional volume increased in all CRF animals. CRF animals showed an increase of glomerular sclerosis index (GSI) and tubulointerstitial damage (TID) but in a smaller proportion in male castrated animals; the opposite occurred with females: castration induced an increase of these parameters. CRF animals showed increased cortical and glomerular fibronectin (FN) rates. Castration decreased glomerular and cortical FN rates in CRFM but not in females. In conclusion, proteinuria was higher in CRFM and probably led to glomerular and interstitial damage, as well as to FN accumulation, castration seems to protect against development of PTN, TID and FN accumulation in males. Castrated female rats presented mesangial expansion, with no changes in PTN, TID and FN rates. It seems that female sex hormones do not protect against renal disease progression, instead, we suggest that male sex hormones lead to acceleration of CRF.

Normal renal dimensions in a specific population.

INTRODUCTION: Renal dimensions (RD) are important for the diagnostic and the prognostic of nephropathies. MATERIALS AND METHODS: We selected 904 Brazilians subjects with normal excretory urographies, showing dense nephrogram at the 5th minute of the exam, serum creatinine < 1.3mg/dl, and absence of any disease that could modify RD. Length, width, and area of both kidneys were correlated with gender, age, height, and body weight. Five hundred and eighty one subjects were men (64.3%) and 323 were women (35.7%). Age ranged from 21 to 87 years old, body weight from 40 to 106kg (69.9+/-9.5 for men and 62.4+/-9.7 for women), and height from 1.37 to 1.94m (1.68+/-0.07 for men and 1.57+/-0.07 for women). RESULTS: There was an association (one-way Anova test) between length, width, and area, for each kidney and for both, with height (p<0.001), body weight (p<0.001), and gender (p<0.001). After adjustment for height (covariance analysis), both gender and body weight did not show influence on RD. Renal length and area reduced with aging (p<0.001), from the 7th decade compared to the others. Excluding these patients, height was the only variable to show association with RD, justifying data stratification by this variable. CONCLUSIONS: Renal length in this population showed that the normal patterns defined by other studies are inadequate for our population. Adjusting the data by height, gender, and body weight did not influence RD; however, the left kidney was bigger than the right kidney. Also, the influence of height was more pronounced below 1.66m.