High-molecular weight adiponectin isoforms increase after biliopancreatic diversion in obese subjects

Objective: Our objective was to test the effect of biliopancreatic diversion (BDP) in adiponectin multimerization. Adiponectin, the major protein secreted by adipose tissue, circulates in plasma in different isoforms. The most clinically relevant oligomers are high‐molecular weight (HMW) multimers and low‐molecular weight (LMW) trimers. Contrasting data on the effect of weight loss on adiponectin isoforms have been reported. Research Methods and Procedures: We measured total plasma adiponectin and HMW and LMW adiponectin oligomers (by Western blot analysis) before and 1 month after BPD, in 18 severely obese subjects. Results: One month after BPD, body weight decreased ～11%. Total adiponectin showed significant increase after BPD. In addition, we found a significant increase in HMW (percentage) adiponectin oligomers. We found a significant inverse correlation between HMW (percentage) and BMI before and after BPD. Homeostasis model of assessment‐insulin resistance decreased significantly after the BPD, without any significant correlation with total serum adiponectin and adiponectin oligomers. Discussion: A moderate weight loss after BPD increases total and HMW adiponectin oligomers. The significant correlation between BMI and HMW (percentage) adiponectin oligomers but not between BMI and total adiponectin might indicate a role of body fat mass in regulation of adiponectin multimerization. These data suggest that HMW oligomers represent a very sensitive parameter to short‐term BMI changes after BPD.     

Durable remission of diabetes after bariatric surgery: What is the underlying pathway?

Background: In the past, type 2 diabetes mellitus (DM) was regarded as a progressive, incurable disease for which palliative therapy could not, over the long term, prevent the associated amputations, blindness, renal failure, and early mortality. This is no longer true. Full and durable remission of type 2 DM, with major decreases in morbidity and mortality, is now achieved regularly with several types of surgery that reduce contact between food and the foregut.Objectives: The aims of this article are to review the impact of bariatric surgery on obesity, remission of DM, and obesity-related morbidity and mortality, and the possible mechanisms for this advance.Methods: This article is based on our 2 meta-analyses of the literature published through April 30, 2006, as well as the most significant reports in the bariatric surgical literature that have been published in English since April 30, 2006. The studies included in our second meta-analysis provided the details of the methodology for the present literature review, including the levels of evidence.Results: Results of our 2 meta-analyses were published previously. Briefly, the analyses revealed that the clinical and laboratory manifestations of type 2 DM resolved or improved in most of the patients who underwent bariatric surgery; the responses were greatest in the patients who lost the most excess body weight; and the improvements were maintained for ≥2 years. The studies reported that intestinal operations such as gastric bypass reduced contact between food and the foregut, produced full and durable remission of DM, reduced mortality, and reversed other comorbidities associated with severe obesity (eg, asthma, gastroesophageal reflux, hypertension, stress incontinence). Insulin levels decreased markedly after surgery, as did glycosylated hemoglobin (A1C) and fasting blood glucose levels. Although these effects were initially attributed to weight loss, the rapid reversal of DM within a matter of days after surgery suggest that bariatric surgery changes the signaling mechanism of the gut with pancreatic islet cells, muscles, fat, the liver, and other organs.Conclusions: Bariatric surgery has opened new vistas, producing durable full remission of type 2 DM—a breakthrough previously considered impossible—with normalization of A1C levels over time and discontinuation of all antidiabetes medication for many patients. These advances create new opportunities for exploring the mechanisms of type 2 DM and its control through pharmaceutical approaches. DM is no longer an irreversible, incurable, or hopeless disease.     

Psychosocial and Behavioral Aspects of Bariatric Surgery

Bariatric surgery has become an increasingly popular treatment option for individuals with extreme obesity (defined as a BMI ≥ 40 kg/m²) or those with less severe obesity accompanied by significant comorbidities. Sustained postoperative weight loss and improvements in obesity‐related health problems make bariatric surgery the most effective treatment for this population. Nevertheless, most experts agree that psychosocial and behavioral factors contribute to successful postoperative outcomes. This paper reviews the literature on the preoperative psychosocial status, eating behaviors, and quality of life of patients who seek bariatric surgery. In addition, the paper examines studies that investigated changes in these factors postoperatively. The review concludes with an agenda for future research in this area.     

Binge Status and Quality of Life after Gastric Bypass Surgery: A One‐Year Study

Objective: This study evaluated gastric bypass surgery outcomes according to presurgical binge eating severity. Research Methods and Procedures: Adult patients completed assessment questionnaires including the Short Form‐36, Gormally Binge Eating Scale (BES), and Beck Depression Inventory (BDI) before and 12 months after surgery. Results: One hundred nine patients (18 men, 91 women) were recruited. Based on their baseline BES scores, patients were non‐ [n = 52 (48%)], moderate [n = 31 (28%)], or severe [n = 26 (24%)] binge eaters. Although the percentage of excess weight loss was greatest after 12 months in the severe binge eaters, the difference among groups was not significant. Severe binge eaters had higher baseline BDI scores than either non‐ or moderate binge eaters (p = 0.001). After surgery, BDI scores declined significantly in all groups from the baseline scores but remained higher postoperatively in the severe binge eaters (p = 0.018). BES scores declined significantly (p = 0.000) after surgery within all groups. There was no difference in the Short Form‐36 physical component summary scores at baseline among groups. Mental component summary scores were significantly lower in the severe binge eaters (p = 0.001). After surgery, there was no difference among groups in either physical or mental component summary scores. Discussion: In conclusion, data from the present study suggest that patients have similar outcomes in terms of improved depression scores, binge eating behavior, and health‐related quality of life regardless of their binge eating severity before surgery. Patients with the most severe binge eating behavior before surgery showed the most improvement when assessed 12 months after surgery.     

Behavioral and Psychological Factors in the Assessment and Treatment of Obesity Surgery Patients

Objective: To provide evidence‐based guidelines on the psychological and behavioral screening of weight loss surgery (WLS) candidates and the impact of psychosocial factors on behavior change after gastric bypass surgery. Research Methods and Procedures: The members of the Behavioral and Psychological subgroup of the Multidisciplinary Care Task Group conducted searches of MEDLINE and PubMed for articles related to WLS, behavior changes, and mental health, including quality of life (QOL) and behavior modification. Pertinent abstracts and literature were reviewed for references. A total of 198 abstracts were identified; 17 papers were reviewed in detail. Search periods were from 1980 to 2004. Results: We found a high incidence of depression, negative body image, eating disorders, and low QOL in severely obese patients. Our task subgroup recommended that all WLS candidates be evaluated by a licensed mental health care provider (i.e., psychiatrist, psychologist, or social worker), experienced in the treatment of severely obese patients and working within the context of a multidisciplinary care team. We also recommended development of pre‐ and postsurgical treatment plans that address psychosocial contraindications for WLS and potential barriers to postoperative success. Discussion: The psychological consequences of obesity can range from lowered self‐esteem to clinical depression. Rates of anxiety and depression are three to four times higher among obese individuals than among their leaner peers. A comprehensive multidisciplinary program that incorporates psychological and behavior change services can be of critical benefit in enhancing compliance, outcome, and QOL in WLS patients.     

Accuracy of self-reported weight among bariatric surgery candidates: the influence of race and weight cycling

Objective: Research on the accuracy of self‐reported weight has indicated that the degree of misreporting (underestimating) weight is associated with increasing weight but is variable across patient groups. We examined the degree of discrepancy between actual and self‐reported BMI in severely obese bariatric surgery candidates, and whether the degree of accuracy varied by race and by eating‐related and psychological factors. Research Methods and Procedures: Participants were 179 obese female gastric bypass surgery candidates (31 black, 22 Hispanic, 126 white) who were asked to self‐report height and weight as part of a larger assessment battery. Actual height and weight were then measured and a discrepancy score was generated (actual BMI ? reported BMI). Results: In this group of severely obese patients, degree of misreporting was unrelated to BMI. The race groups did not differ in actual or self‐reported BMI but differed significantly in the degree of misestimation between self‐reported and actual BMI. Post hoc tests indicated that black women underestimated their BMI significantly more than white women; Hispanic women did not differ from the other race groups. No eating‐related or psychological variables assessed predicted percentage discrepancy; however, the accuracy in self‐reported weight was related to history of weight cycling. Discussion: Overall, obese bariatric surgery candidates were accurate in self‐report of weight, although the degree of accuracy differed by race and weight cycling history.     

Differential effects of gastric bypass and banding on circulating gut hormone and leptin levels

Objective: To quantify plasma concentrations of hormones that regulate energy homeostasis in order to establish possible mechanisms for greater weight loss after Roux‐en‐Y gastric bypass (RYGBP) compared with gastric banding (BND). Research Methods and Procedures: Four groups of women were studied: lean (n = 8; mean BMI, 21.6 kg/m²); BND (n = 9; BMI, 35.8; 25% weight loss), RYGBP (n = 9; BMI, 34.2; 36% weight loss), and controls matched for BMI to the surgical groups (n = 11; BMI, 34.4). Results: Fasting total peptide YY (PYY) and PYY_(3–36) immunoreactivity were similar among all groups, but the postprandial response in the RYGBP group was exaggerated, such that 30 minutes after the meal, total and PYY_(3–36) levels were 2‐ to 4‐fold greater compared with all other groups. Maximal postprandial suppression of total ghrelin was blunted in the BND group (13%) compared with RYGBP (27%). Postprandial suppression of octanoylated ghrelin was also less in BND (29%) compared with RYGBP (56%). Fasting insulin was lower in RYGBP (6.6 μU/mL) compared with BND (10.0 μU/mL). Compared with lean controls, leptin concentrations were significantly higher in BND but not in RYGBP. There was a greater increase in post‐meal satiety in the RYGBP group compared with BND and overweight controls. Discussion: The differences between RYGBP and BND subjects in postprandial concentrations of PYY and ghrelin would be expected to promote increased satiety and earlier meal termination in RYGBP and may aid in greater weight loss. The differences in insulin and leptin concentrations associated with these procedures may also reflect differences in insulin sensitivity and energy partitioning.     

The Insulin Tolerance Test in Morbidly Obese Patients Undergoing Bariatric Surgery

Objective: To assess the effect of massive weight loss in relation to insulin resistance and its correlation to changes in glycemic homeostasis and lipid profile in severely obese patients. Research Methods and Procedures: A prospective clinical intervention study was carried out with 31 morbidly obese women (body mass index: 54.2 ± 8.8 kg/m²) divided into three groups according to their glucose tolerance test: 14 normal, 8 impaired glucose tolerance, and 9 type 2 diabetes. All subjects underwent an insulin tolerance test with intravenous bolus of 0.1 U insulin/kg body weight before silastic ring vertical gastroplasty Roux‐en‐Y gastric bypass surgery, and again at 2, 4, 6, and 12 months postoperatively. Fasting plasma glucose, hemoglobin A1c, and lipid profile were also evaluated. Results: A reduction of 68 ± 15% in initial excess body weight was evident within 1 year. Along with weight loss, the following statistically significant changes were found: an increase in the insulin‐sensitivity index (Kitt) and a decrease in fasting plasma glucose and hemoglobin A1c, most notably in the type 2 diabetes group. An overall improvement in lipid profile was observed in all three groups. Discussion: Bariatric surgery was an effective therapeutic approach for these obese patients because it reduced both weight and insulin resistance, along with improving metabolic parameters. Significant correlations were found between insulin resistance and metabolic improvements. Weight loss after bariatric surgery induced an improvement in metabolic fitness, related to the reduction in insulin resistance over a range of glucose tolerance statuses from normal to diabetic.