Changes in Gut Hormones in Relation to Cardiovascular Risk Factors One Year After Laparoscopic Gastric Banding Surgery

Title: Changes in Gut Hormones in Relation to Cardiovascular Risk Factors One Year After Laparoscopic Gastric Banding Surgery Purpose: Obesity rates in the United States continue to rise at an alarming rate, imposing increasingly large health burdens such as cardiovascular disease and diabetes among others. Existing research on gastric bypass surgery has shown that improved gut hormone levels post-surgery are partially responsible for drastic improvements in cardiovascular health. However, similar research studying this effect in laparoscopic gastric banding surgery (LBS) is lacking. The purpose of the current study is to determine whether LBS delivers normalization of gut hormones, specifically ghrelin and GLP-1 and whether that normalization could explain improvements in cardiovascular (CV) indicators of health. Methods: A secondary data analysis was conducted on data from a 1-year prospective study in a community bariatric surgical setting. Bariatric patients who completed baseline (T1) and 12-month post-LBS were included in this analysis (n=29). There were 22 women and 7 men. The average age was 45 years old (sd =11.6) and mean Body Mass Index was 42 kg/m2 (sd =5). Subjects were assessed at before surgery (T1) and 12 months post-surgery (T3) for fasting and postprandial levels of active ghrelin and glucagon like peptide (GLP-1) as well as for indicators of cardiovascular and metabolic health including high density lipoprotein (HDL), lipoprotein (a) (Lipo-a), apolipoprotein A1 (Apo-A1), apolipoprotein B (ApoB), and plasma renin activity (PRA). CV indicators were analyzed at a commercial laboratory. Ghrelin, GLP-1, and PRA were analyzed in-house. Central adiposity at L4L5 was assessed using CT scan. Change scores between T1 and T3 were calculated. Partial correlation was used to examine relationships between change scores in CV indicators with ghrelin and GLP-1, controlling for change in L4L5VAT. Results: The partial correlations of change scores showed that increased levels of postprandial GLP-1 correlated with a reduction in Lipo-a plasma levels (r=-.752, p=.012). The results also showed that increased levels in fasting GLP-1 correlated with a decrease in levels of ApoB in plasma (r=-.686, p=.028). Conclusion: Improvements in secretion patterns 12 months after LBS appears to have a significant relationship to changes in CV risk factors such as Lipoprotein (a) and ApoB. Increased GLP-1 levels appear particularly related to plasma levels of lipoprotein (a) as well as ApoB which could be an indicator of GLP-1 playing an important role in lipid metabolism.