One Anastomosis Gastric Bypass (OAGB) and Sleeve Gastrectomy (SG) are the most common bariatric procedures performed worldwide. SG is a restrictive procedure whereas OAGB involves malabsorption as well, supposing a risk of deficiency development post OAGB. The aim of the study was to compare nutritional deficiencies and metabolic markers one year after the procedures, while adhering to the current protocols. Retrospective analysis was performed for data on 60 adults undergoing primary OAGB, compared to 60 undergoing primary SG. Mean pre-surgery BMI for SG was 42.7 kg/m² and 43.3 kg/m² for OAGB. A multidisciplinary team followed up with the patients at least 3 times during the first year. Mean weight loss was 39.0 kg for SG and 44.1 kg for OAGB. The OAGB group presented a significantly sharper decline in T.Chol and a trend for sharper LDL decrease; a higher increase in folate and a trend for a greater decrease in albumin and hemoglobin were observed in OAGB. For vitamin B12, D, iron and ferritin, no difference was observed between the treatment groups, although there were some in-group differences. Nutritional recommendations and adopted supplement plans minimize the risk of deficiencies and result in improvement in metabolic biomarkers one year after OAGB, which was comparable to SG.

Bariatric surgeries may lead to an improvement in metabolic fatty liver disease, and a reduction in the levels of the hepatic enzyme Alanine Aminotransferase (ALT). We compared the effects of Sleeve Gastrectomy (SG), Roux en Y Gastric Bypass (RYGB) and One Anastomosis Gastric Bypass (OAGB) on the levels of ALT by analysis of two-year follow-up data from 4980 patients in the Israeli Bariatric Registry that included laboratory tests and demographic information. Pre-operative characteristics of patients, and particularly levels of liver enzymes, were similar across surgery types. Regression modeling and retrospective matching showed that SG was superior to RYGB and OAGB in reducing ALT levels, and in reducing the fraction of patients with abnormally high ALT levels. Two-year post-surgery, an increase in ALT levels from normal to abnormal levels was observed in 5% of SG patients, and in 18% and 23% of RYGB and OAGB patients. In conclusion, SG leads to a greater reduction in ALT levels compared with bypass surgeries and a lower incidence of post-surgical elevation of ALT levels. Further studies are required to identify the cause for the rise in liver enzymes, and to determine whether ALT levels correlate with liver pathology especially following bariatric surgery.

We report the long-term response to bariatric surgery in a singular family of four adolescents with severe obesity (41–82 kg/m²), homozygous for the C271R loss-of-function mutation in the melanocortin 4 receptor (MC4R), and three adults heterozygous for the same mutation. All patients had similar sociodemographic backgrounds and were followed for an average of 7 years. Three of the four homozygous patients regained their full weight (42–77 kg/m²), while the fourth lost weight but remained obese with a body mass index of 60 kg/m². Weight regain was associated with relapse of most comorbidities, yet hyperglycemia did not relapse or was delayed. A1c levels were reduced in homozygous and heterozygous patients. The long-term follow-up data on this very unique genetic setting show that weight loss and amelioration of obesity following bariatric surgery require active MC4R signaling, while the improvement in glycemia is in part independent of weight loss. The study validates animal models and demonstrates the importance of biological signaling in the regulation of weight, even after bariatric surgery.

Patients that undergo bariatric surgery experience weight loss and a reduction in the plasma levels of the hepatic enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). We used the Israeli national bariatric registry, which includes demographic, clinical, and biochemical data on 19,403 patients, of which 1335 patients had two-year follow-up data on ALT, AST, A1C, and BMI, to test the dependence of the reduction in the levels of ALT and AST on weight loss. The data were analyzed using regression models, retrospective matching, and time course analyses. Changes in liver enzymes did not correlate with change in BMI, and linear regression models did not demonstrate that the change in ALT and AST values were dependent on pre-operative levels of BMI or the extent of weight loss. ALT and AST levels were reduced two years after surgery compared with a cohort of retrospectively matched patients for ethnicity, sex, age, BMI, and A1C. Finally, patients who regained weight displayed a reduction in levels of liver enzymes. Our results suggest that bariatric surgery affects AST and ALT levels via weight loss dependent and independent mechanisms. Mechanistic studies that will identify the nature of this effect and the clinical relevance of ALT and AST levels to the post-bariatric liver function are warranted.