Serum cystatin C in relation to fat mass loss after bariatric surgery

Serum cystatin C concentration, generally accepted as renal function marker, is associated with cardiovascular risk and metabolic syndrome. Recent studies indicate that cystatin C increases in human obesity and that adipose tissue contributes to enhanced serum cystatin C concentration in obese subjects. The aim of the study was to assess whether a reduction in body and fat mass after bariatric surgery has any impact on serum cystatin C concentrations.

Serum from 27 obese patients were tested before and 6 months after bariatric surgery. Twenty healthy subjects with normal body weight served as controls. Serum cystatin C concentrations were assayed by ELISA.

Serum cystatin C concentrations were significantly higher in obese patients compared with non-obese subjects. Decrease of body and fat mass after bariatric surgery resulted in improvement of several parameters associated with cardiovascular risk and metabolic syndrome, like serum lipids, blood pressure and insulin sensitivity. Surprisingly the mean postoperative serum cystatin C concentration was not significantly different from that before surgery. Serum creatinine and GFR also remained unchanged.

The results presented here suggest that serum cystatin C concentration is not tightly associated with body and fat mass loss in obese patients after bariatric surgery.