Proteinuria and its relation to diverse biomarkers and body mass index in chronic hemodialysis

Hernán Trimarchi,¹ Alexis Muryan,² María-Soledad Raña,¹ Pedro Paggi,² Fernando Lombi,¹ Mariano Forrester,¹ Vanesa Pomeranz,¹ Alejandra Karl,¹ Mirta Alonso,² Pablo Young,³ Mariana Dicugno<sup>2

1</sup>Department of Nephrology, ²Department of Biochemistry, ³Department of Internal Medicine Services, Hospital Británico de Buenos Aires, Buenos Aires, Argentina

Background: Certain adipokines exert direct effects on proteinuria, a cardiovascular risk factor ignored in hemodialysis. We measured different adipokines according to body mass index (BMI) in relation to proteinuria.
Methods: Patients numbered 57: group A (GA), BMI < 25, n = 22; GB, BMI 25–30, n = 15; and GC, BMI > 30, n = 20. There were no statistical differences in age, sex, time on dialysis, cause of renal failure, diabetes, hypertension, C-reactive protein, or nutritional status. Measures were taken of 24-hour diuresis and proteinuria, ultrafiltration, albumin, pro-brain natriuretic peptide (Pro-BNP), insulin, adiponectin, leptin, and ghrelin.
Results: Proteinuria was significantly higher in GC versus (vs) GA (1.5 g/day, range 0.30–14 vs 0.72 g/day, range 0.1–2.7; P < 0.01) and correlated significantly with leptin levels (ρ = 0.47, P > 0.05). In GA, elevated levels of Pro-BNP, adiponectin, and ghrelin were associated with lower degrees of proteinuria. Significant correlations were found between adiponectin and leptin (ρ = -0.54, P = 0.03), and adiponectin and Pro-BNP (ρ= 0.59, P = 0.02). Though not significant, there were more diabetics in GC (GA four, GB three, GC ten). As BMI increased in GB and GC, Pro-BNP, adiponectin, and ghrelin levels decreased significantly, while proteinuria, insulin, and homeostasis model assessment of insulin resistance increased. Leptin levels were significantly elevated in GC vs GA and GB. In GC, ghrelin correlated significantly with Pro-BNP (ρ= 0.51, P = 0.03), while leptin correlation with Pro-BNP was inverse and significant in GA (ρ = -0.74, P > 0.001) and inverse and nonsignificant in GB and GC.
Conclusion: In patients with BMI < 25, higher adiponectin, ghrelin, and Pro-BNP levels were associated with lower proteinuria and leptinemia. In obesity, hyperleptinemia and hyperinsulinemia associated with higher proteinuria; whether decreased adiponectin–ghrelin–ProBNP and/or elevated leptin–insulin levels aggravate proteinuria remains to be determined.

Keywords: proteinuria, adiponectin, ghrelin, leptin, Pro-BNP, hemodialysis, BMI