Background: Data examining the effect of different bariatric procedures on adipokines in humans is lacking. We examined the effect of weight loss following bariatric surgery on glycaemia, retinol-binding protein 4 (RBP4), fibroblast growth factor-21 (FGF21) and C-reactive protein (CRP).
Methods: We studied participants who underwent weight loss with diet (n=16), gastric banding (GB n=11), sleeve gastrectomy (SG n=21) and Roux-en-Y gastric bypass (RYGB n=7). Anthropometrics, HbA1c, RBP4, FGF21 and CRP were measured at baseline, 1, 3, 6 and 12 months.
Results: At baseline, mean weight was 116(±21)kg and BMI was 40(±6)kg/m2. 29% had diabetes. Positive correlations were observed between CRP and baseline weight (r=0.357, p=0.007) and waist circumference (r=0.358, p=0.007) and between FGF21 and baseline waist circumference (r=0.361, p=0.007) and HbA1c (r=0.426, p=0.001), but not weight. RBP4 did not correlate with any parameter.
Weight significantly decreased over 6 months after all interventions (p<0.01). Subsequent weight loss only occurred in surgical groups, with 12 month weight loss greatest in RYGB of 39.4kg (95%CI: 31.0, 47.8), followed by SG 33.1kg (28.1, 38.0) and GB 16.6 kg (9.8, 23.3).
Significant changes in adipokines occurred after surgery, but not diet. CRP decreased in a similar trajectory to weight (p<0.05), with the greatest decrease in RYGB of 83% (69%, 91%). RBP4 declined by 32% (16%, 45%) in the first month following RYGB (p=0.0004), but subsequently rose and was not significantly different from baseline by 12 months. FGF21 declined 12 months post-RYGB by 55% (4%, 78%) (p=0.04). In contrast, FGF21 increased by 105% (27%, 235%) 3 months post-SG (p=0.004), but was not significantly different to baseline at 6 months.
Conclusion: Bariatric surgical procedures had differential effects on adipokines. Unlike CRP, changes in FGF21 and RBP4 did not parallel changes in weight. The role of these adipokines in mediating metabolic effects of bariatric surgery deserves further study.