Role of nutritional ketosis in the improvement of metabolic parameters following bariatric surgery

BACKGROUND Ketone bodies(KB)might act as potential metabolic modulators besides serving as energy substrates.Bariatric metabolic surgery(BMS)offers a unique opportunity to study nutritional ketosis,as acute postoperative caloric restriction leads to increased lipolysis and circulating free fatty acids.AIM To characterize the relationship between KB production,weight loss(WL)and metabolic changes following BMS.METHODS For this retrospective study we enrolled male and female subjects aged 18-65 years who underwent BMS at a single Institution.Data on demographics,anthropometrics,body composition,laboratory values and urinary KB were collected.RESULTS Thirty-nine patients had data available for analyses[74.4%women,mean age 46.5±9.0 years,median body mass index 41.0(38.5;45.4)kg/m^(2),fat mass 45.2%±6.2%,23.1%had diabetes,43.6%arterial hypertension and 74.4%liver steatosis].At 46.0±13.6 d post-surgery,subjects had lost 12.0%±3.6%of pre-operative weight.Sixty-nine percent developed ketonuria.Those with nutritional ketosis were significantly younger[42.9(37.6;50.7)years vs 51.9(48.3;59.9)years,P=0.018],and had significantly lower fasting glucose[89.5(82.5;96.3)mg/dL vs 96.0(91.0;105.3)mg/dL,P=0.025]and triglyceride levels[108.0(84.5;152.5)mg/dL vs 152.0(124.0;186.0)mg/dL,P=0.045]vs those with ketosis.At 6 mo,percent WL was greater in those with postoperative ketosis(-27.5%±5.1%vs 23.8%±4.3%,P=0.035).Urinary KBs correlated with percent WL at 6 and 12 mo.Other metabolic changes were similar.CONCLUSION Our data support the hypothesis that subjects with worse metabolic status have reduced ketogenic capacity and,thereby,exhibit a lower WL following BMS.

Predictors for advanced fibrosis in morbidly obese nonalcoholic fatty liver patients

AIMTo investigate predictors for fibrosis specifically in a high risk population of morbidly obese patients, including detailed evaluation of lifestyle. METHODSWe conducted a cross-sectional study among morbidly obese patients attending the bariatric clinic at the Tel-Aviv Medical Center between the years 2013-2014 with body mass index (BMI) above 40 or above 35 with co-morbidity. Patients with serum hepatitis B surface antigen or anti-hepatitis C virus antibodies, genetic liver diseases, autoimmune disease or high alcohol intake (≥ 30 g/d in men or ≥ 20 g/d in women) were excluded from the study. Liver fibrosis was estimated by transient elastography (FibroScan®), using the ‘‘XL’’ probe. We collected data on age and gender, education, smoking status and amount, medical history, nutrition and lifestyle habits. All these data were collected using structured and validated questionnaires. Fasting blood test were available for a subsample. RESULTSFibroscan was performed on a total of 91 patients, of which 77 had a valid examination according to the accepted criteria. Of those, 21% had significant fibrosis (F2) and 39% had advanced or severe fibrosis (F3 or F4). In multivariate analysis, male gender and BMI had a positive association with advanced fibrosis; the OR for fibrosis F ≥ 2 was 7.93 (95%CI: 2.36-26.64, P = 0.001) for male gender and 1.33 (1.11-1.60 kg/m2, P = 0.002) for BMI. The OR for fibrosis F ≥ 3 was 2.92 (1.08-7.91, P = 0.035) for male gender and 1.17 (1.03-1.33, P = 0.018) for BMI. Subjects were categorized to subgroups based on the combination of male gender and BMI of 40 and above. A significant dose response association with stiffness level was noted across these categories, with the highest stiffness among men with a higher BMI (P = 0.001). In addition, a significant positive correlation between pack-years cigarette smoking and liver stiffness was demonstrated among men (r = 0.54, P = 0.012). CONCLUSIONIn the morbidly obese population, a higher BMI, male gender and degree of smoking in men bears a greater risk for advanced nonalcoholic fatty liver disease.