Omentin changes following bariatric surgery and predictive links with biomarkers for risk of cardiovascular disease

Abstract

Background: Although no receptor has yet been identified, changes in circulating levels of the adipokine designated as Omentin have been demonstrated in obesity and related comorbidities such as cardiovascular disease, insulin resistance, metabolic syndrome and chronic inflammation.

Methods: Changes in Omentin levels at 1 and 5 days and 6 and 12 months in response to biliopancreatic diversion with duodenal switch bariatric surgery were evaluated, specifically to investigate if changes preceded gain of insulin sensitivity.

Results: Pre-operative plasma Omentin was not different between men (n = 18) vs women (n = 48), or diabetic status but correlated with body mass index (BMI). Altogether, Omentin increased as early as 24-h post-surgery, with changes maintained up to 1-year. Fifty-nine percent of subjects increased Omentin >10% by 24-H following surgery (OmentinINC p < 0.0001), while 18% of subjects decreased (OmentinDEC p < 0.0001), with changes maintained throughout one-year. These two groups had comparable age, sex distribution, diabetes, BMI, waist circumference and fat mass, however OmentinDEC had elevated levels of cardiovascular risk markers; homocysteine (p = 0.019), NT-proBNP (p = 0.006) and total bilirubin (p = 0.0001) while red blood cell (RBC) count was lower (p = 0.0005) over the one-year period. Omentin levels at 1-DAY also correlated with immune parameters (white blood cell count, % neutrophil, % monocytes, % lymphocytes).

Conclusion: OmentinDEC at 1 day following surgery may be a marker of cardiovascular "at-risk" group before weight loss or insulin sensitivity restoration.

Figures

Figure 1

Circulating Omentin levels and correlations in preoperative state. Fasting Omentin levels in the preoperative state were measured in all subjects. A: Fasting Omentin levels separated based on sex and presence/absence of diabetes. Results are given as mean ± SEM. B and C: Correlation (Spearman) of Omentin levels to lymphocyte counts and circulating acylation stimulating protein (ASP).

Figure 2

Fasting pre-operative and post-operative Omentin levels. A: Fasting levels of Omentin were measured pre-operative, and at 1 day, 5 days, 6 months and 12 months post-operatively. Results are presented as average ± SEM with analysis by ANOVA vs pre-operative levels. B: Pre-operative and 1 day levels of Omentin are given individually for subjects separated based on >10% increase (OmentinINC), >10% decrease (OmentinDEC), and no change in Omentin (neutral = OmentinNEU). C: Percent Omentin change across all time points is given for the OmentinINC (solid line) and the OmentinDEC (dotted line) group. Results are presented as average ± SEM with analysis by 2-way ANOVA. Significance is presented as *p < 0.05, **p < 0.01 and ***p < 0.001.

Figure 3

Pre-operative and post-operative results for cardiovascular risk factors presented for groups based on OmentinINCand OmentinDEC. Preoperative and postoperative results are presented for homocysteine (A), NT-proBNP (B), total bilirubin (C) and red blood cell counts (D) for the OmentinINC (solid line) and OmentinDEC (dotted line) groups over one year follow-up. Results are expressed as average ± SEM with analysis by 2-way ANOVA, significance for groups difference is indicated with post-hoc comparisons indicated: *** p < 0.001.