Renal cytokines improve early after bariatric surgery

BACKGROUND: Bariatric surgery has been suggested to improve arterial hypertension and renal function. This prospective controlled observational study aimed to investigate changes in renal inflammation, renal function and arterial blood pressure before and after bariatric surgery. METHODS: Blood pressure was measured, and urine and blood samples were collected from 34 morbidly obese patients before and 4 weeks after bariatric surgery. Serum levels of cystatin C, creatinine, albumin, cholesterol and C-reactive protein (CRP) were measured, along with urinary cytokine/creatinine ratios for macrophage migration inhibitory factor (MIF), monocyte chemotactic protein (MCP) 1, chemokine ligand (CCL) 18 and CCL-15. RESULTS: Mean(s.e.m.) bodyweight dropped from 124·1(2·6) to 114·8(2·4) kg (P < 0·001) and mean arterial blood pressure decreased from 105·7(1·8) to 95·5(1·2) mmHg (P < 0·001) in 4 weeks. Systemic and urinary inflammatory markers improved, with a reduction in serum CRP level (P < 0·001), and decreased urinary MIF/creatinine (P < 0·001), MCP-1/creatinine (P < 0·001) and CCL-18/creatinine (P = 0·003) ratios. In contrast, urinary CCL-15/creatinine ratios did not change and the glomerular filtration rate, measured by serum cystatin C, was unchanged (P = 0·615). CONCLUSION: Surgically induced weight loss contributed to a decrease in blood pressure and markers of renal inflammation. The reduced levels of CRP and urinary cytokines suggest that bariatric surgery attenuates systemic and renal inflammatory status.