Breast cancer biomarkers predict weight loss after gastric bypass surgery

Background

Infections with polyomavirus BK virus (BKV) are a common cause of renal dysfunction after renal transplantation and may also be harmful in surgical patients with shock. The aim of the present study was to determine the frequency of BKV viremia in critically ill surgical patients with septic or hemorrhagic shock, and, if viremia is detectable, whether viremia may be associated with renal dysfunction.

Findings

A total of 125 plasma samples from 44 critically ill surgical patients with septic or hemorrhagic shock were tested by real-time polymerase chain reaction (PCR) for BKV DNA during their stay on the intensive care unit (ICU). BKV viremia occurred in four patients, i.e. in three of the septic and in one of the hemorrhagic shock group. There was no association between viremia and renal dysfunction. All positive samples contained a low viral load (< 500 copies/ml).

Conclusions

Since BK viremia was rarely found and with low viral load only in critically ill surgical patients with shock, it is very unlikely that BK viremia results in BK nephropathy later on.     

Effects of weight loss,induced by gastric bypass surgery,on HDL remodeling in obese women

Plasma lipoproteins and glucose homeostasis were evaluated after marked weight loss before and over 12 months following Roux-en-Y gastric-bypass (RYGBP) surgery in 19 morbidly obese women. Standard lipids, remnant-lipoprotein cholesterol (RLP-C); HDL-triglyceride (TG); apolipoproteins (apo) A-I, A-II, E, and A-I-containing HDL subpopulations; lecithin-cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) mass and activity; plasma glucose and insulin levels were measured before and at 1, 3, 6, and 12 months after GBP surgery. Baseline concentrations of TG, RLP-C, glucose, and insulin were significantly higher in obese than in normal-weight, age-matched women, whereas HDL cholesterol (HDL-C), apoA-I, apoA-II, α-1 and α-2 levels were significantly lower. Over 1 year, significant decreases of body mass index, glucose, insulin, TG, RLP-C, HDL-TG, and preβ-1 levels were observed with significant increases of HDL-C and α-1 levels (all P < 0.05). Changes of fat mass were correlated with those of LDL cholesterol (P = 0.018) and LCAT mass (P = 0.011), but not with CETP mass (P = 0.265). Changes of fasting plasma glucose concentrations were inversely correlated with those of CETP mass (P = 0.005) and α-1 level (P = 0.004). Changes of fasting plasma insulin concentrations were positively correlated with those of LCAT mass (P = 0.043) and inversely with changes of α-1 (P = 0.03) and α-2 (P = 0.05) concentrations. These results demonstrate beneficial changes in HDL remodeling following substantial weight loss induced by RYGBP surgery and that these changes are associated with improvement of glucose homeostasis in these patients.     

Increase in visfatin after weight loss induced by gastroplastic surgery

Objective: The recently described adipokine visfatin is produced in visceral fat and has been suggested to influence insulin resistance. To investigate whether visfatin concentrations are related to changes in body weight, this adipokine was measured in insulin‐resistant severely obese patients before and after gastroplastic surgery. Research Methods and Procedures: Visfatin, interleukin‐6, high‐sensitivity C‐reactive protein, homeostasis model assessment of insulin resistance (HOMA‐IR), and other clinical parameters were assessed in 36 severely obese subjects (28 female; mean age, 43 years) with a median BMI of 44.3 kg/m² (95% confidence interval, 43.3 to 48.1 kg/m²). Results: After surgery, BMI decreased to a median of 31.9 kg/m² (30.1 to 35.1 kg/m²) (p < 0.0001). Median visfatin concentrations increased significantly after weight loss [70.9 ng/mL (61.4 to 75.6 ng/mL) vs. 86.4 ng/mL (79.4 to 89.8 ng/mL); p < 0.0005]. This increase correlated with the decrease of insulin and HOMA‐IR and was associated with a reduction in plasma interleukin‐6 and high‐sensitivity C‐reactive protein concentrations. Discussion: Massive weight loss after gastroplastic surgery is accompanied by an increase in circulating concentrations of the novel adipokine visfatin. This increase correlates with the decrease in plasma insulin concentrations and HOMA‐IR.     

Explanations for weight loss after ileojejunal bypass in gross obesity.

Twenty grossly obese patients underwent ileojejunal bypass operations. Measurements of calories lost in faeces showed that the malabsorption could not account for the weight loss. Furthermore, the malabsorption was not decreased two years after bypass, when weight was no longer being lost. Dietary restriction is therefore largely responsible for the weight loss and increased food intake for weight maintenance.     

Characterization of weight loss and weight regain mechanisms after Roux-en-Y gastric bypass in rats

Roux-en-Y gastric bypass (RYGB) is the most effective therapy for morbid obesity, but it has a approximately 20% failure rate. To test our hypothesis that outcome depends on differential modifications of several energy-related systems, we used our established RYGB model in Sprague-Dawley diet-induced obese (DIO) rats to determine mechanisms contributing to successful (RGYB-S) or failed (RYGB-F) RYGB. DIO rats were randomized to RYGB, sham-operated Obese, and sham-operated obese pair-fed linked to RYGB (PF) groups. Body weight (BW), caloric intake (CI), and fecal output (FO) were recorded daily for 90 days, food efficiency (FE) was calculated, and morphological changes were determined. d-Xylose and fat absorption were studied. Glucose-stimulated vagal efferent nerve firing rates of stomach were recorded. Gut, adipose, and thyroid hormones were measured in plasma. Mitochondrial respiratory complexes in skeletal muscle and expression of energy-related hypothalamic and fat peptides, receptors, and enzymes were quantified. A 25% failure rate occurred. RYGB-S, RYGB-F, and PF rats showed rapid BW decrease vs. Obese rats, followed by sustained BW loss in RYGB-S rats. RYGB-F and PF rats gradually increased BW. BW loss in RYGB-S rats is achieved not only by RYGB-induced decreased CI and increased FO, but also via sympathetic nervous system activation, driven by increased peptide YY, CRF, and orexin signaling, decreasing FE and energy storage, demonstrated by reduced fat mass associated with the upregulation of mitochondrial uncoupling protein-2 in fat. These events override the compensatory response to the drop in leptin levels aimed at conserving energy.     

High allelic burden of four obesity SNPs is associated with poorer weight loss outcomes following gastric bypass surgery

Genome‐wide association and linkage studies have identified multiple susceptibility loci for obesity. We hypothesized that such loci may affect weight loss outcomes following dietary or surgical weight loss interventions. A total of 1,001 white individuals with extreme obesity (BMI >35 kg/m²) who underwent a preoperative diet/behavioral weight loss intervention and Roux‐en‐Y gastric bypass surgery were genotyped for single‐nucleotide polymorphisms (SNPs) in or near the fat mass and obesity‐associated (FTO), insulin induced gene 2 (INSIG2), melanocortin 4 receptor (MC4R), and proprotein convertase subtilisin/kexin type 1 (PCSK1) obesity genes. Association analysis was performed using recessive and additive models with pre‐ and postoperative weight loss data. An increasing number of obesity SNP alleles or homozygous SNP genotypes was associated with increased BMI (P < 0.0006) and excess body weight (P < 0.0004). No association between the amounts of weight lost from a short‐term dietary intervention and any individual obesity SNP or cumulative number of obesity SNP alleles or homozygous SNP genotypes was observed. Linear mixed regression analysis revealed significant differences in postoperative weight loss trajectories across groups with low, intermediate, and high numbers of obesity SNP alleles or numbers of homozygous SNP genotypes (P < 0.0001). Initial BMI interacted with genotype to influence weight loss with initial BMI <50 kg/m², with evidence of a dosage effect, which was not present in individuals with initial BMI ≥50 kg/m². Differences in metabolic rate, binge eating behavior, and other clinical parameters were not associated with genotype. These data suggest that response to a surgical weight loss intervention is influenced by genetic susceptibility and BMI.     

Increased exercise capacity after surgically induced weight loss in morbid obesity

Objective: To investigate the effects of surgically induced weight loss on exercise capacity in patients with morbid obesity (MO). Research Methods and Procedures: A prospective 1‐year follow‐up study was carried out, with patients being their own controls. A symptom‐limited cardiopulmonary exercise stress test was performed in 31 MO patients (BMI > 40 kg/m²) before and 1 year after undergoing bariatric surgery. Results: At 1 year after surgery, weight was reduced from 146 ± 33 to 95 ± 19 kg (p < 0.001), and BMI went from 51 ± 4 to 33 ± 6 kg/m² (p < 0.001). After weight loss, obese patients performed each workload with lower oxygen consumption, heart rate, systolic arterial pressure, and ventilatory volume (p < 0.001). This reduced energy expenditure allowed them to increase the duration of their effort test from 13.8 ± 3.8 to 21 ± 4.2 minutes (p < 0.001). Upon finishing the exercise, MO patients before surgery were able to reach only 83% of their age‐predicted maximal heart rate, and their respiratory exchange ratio was 0.87 ± 0.06. After weight loss, those values were 90% and 1 ± 0.08, respectively (p < 0.01). When we compared the peak O₂ pulse corrected by fat free mass before and after surgery, no significant differences between the groups were found. Discussion: After surgically induced weight loss, MO patients markedly improved their exercise capacity. This is due to the fact that they were able to perform the external work with lower energy expenditure and also to increase cardiovascular stress, optimizing the use of cardiac reserve. There were no differences in cardiac function before and after surgery.     

Capacity for physical activity predicts weight loss after Roux-en-Y gastric bypass

Despite its overall excellent outcomes, weight loss after Roux-en-Y gastric bypass (RYGB) is highly variable. We conducted this study to identify clinical predictors of weight loss after RYGB. We reviewed charts from 300 consecutive patients who underwent RYGB from August 1999 to November 2002. Data collected included patient demographics, medical comorbidities, and diet history. Of the 20 variables selected for univariate analysis, 9 with univariate P values 相似文献   

Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy: understanding weight loss and improvements in type 2 diabetes after bariatric surgery

Obesity increases the likelihood of diseases like type 2 diabetes (T2D), heart disease, and cancer, and is one of the most serious public health problems of this century. In contrast to ineffectual prevention strategies, lifestyle modifications, and pharmacological therapies, bariatric surgery is a very effective treatment for morbid obesity and also markedly improves associated comorbidities like T2D. However, weight loss and resolution of T2D after bariatric surgery is heterogeneous and specific to type of bariatric procedure performed. Conventional mechanisms like intestinal malabsorption and gastric restriction do not fully explain this, and potent changes in appetite and the enteroinsular axis, as a result of anatomical reorganization and altered hormonal, neuronal, and nutrient signaling, are the portended cause. Uniquely these signaling changes appear to override vigorous homeostatic defenses of stable body weight and compelling self-gratifying motivations to eat and to reverse defects in beta-cell function and insulin sensitivity. Here we review mechanisms of weight loss and T2D resolution after Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy bariatric surgery, two markedly different procedures with robust clinical outcomes.     

Weight loss and health outcomes in African Americans and whites after gastric bypass surgery

Objective: The objective was to describe differences in weight loss, dietary intake, and cardiovascular risk factors between white and African‐American patients after gastric bypass (GBP). Research Methods and Procedures: This was a retrospective database review of a sample of 84 adult patients (24 African‐American and 60 white women and men) between the ages of 33 and 53 years. All subjects had GBP surgery in 2001 at the Bariatric Surgery Program at Boston Medical Center in Boston, MA, and were followed for one year postoperatively. Patients were excluded if weight data were missing at baseline, 3 months, or 1 year after GBP. A total of 9 African Americans and 41 whites provided data at all 3 time‐points and were included in the study. Differences in weight loss, diet, and cardiovascular risk factors were analyzed. Results: There were no differences in baseline characteristics between African Americans and whites. Mean weight loss for the entire sample was 36 ± 9%, with a range of 8% to 54% relative to initial body weight. Whites lost more weight (39 ± 8%) than African Americans (26 ± 10%) (p < 0.05). Dietary parameters, as well as improvements in blood pressure and lipid profiles, were similar in the two racial groups. Discussion: Differences in weight loss between severely obese African Americans and whites undergoing open GBP are unlikely to be related to postoperative dietary practices. Our data are consistent with previous reports implicating metabolic differences between the two racial groups.     

Alterations in the common pathway of coagulation during weight loss induced by gastric bypass in severely obese patients

The objective of this study was to establish the relationship between the plasminogen activator inhibitor-1 (PAI-1), antithrombin-III (ATIII), fibrinogen, and white blood cell (WBC) levels in severely obese patients. We analyzed various plasma parameters implicated in the intrinsic and extrinsic coagulation pathway from 34 severely obese patients before and 1, 6, and 12 months after gastric bypass. In obese people, ATIII, fibrinogen, and WBC levels were in the upper limit of the normal range, and all were higher and significantly different from nonobese people. After bariatric surgery, the ATIII level continued to be high during the first month and increased until 12 months, while fibrinogen decreased only at that time. PAI-1 plasma protein and PAI-1 mRNA levels in liver and adipose tissue show similar profiles and had a strong positive correlation (r = 0.576, P = 0.0003 in liver; r = 0.433, P = 0.0004 in adipose tissue). They were higher in obese patients compared with nonobese control, but tended to recover normal values 1 month after surgery. Thus, the liver and adipose tissue could be an important source of PAI-1 protein in plasma. Gastric bypass surgery leads to a normalization of the hematological profile and a decrease in PAI-1 levels, which entails a decrease of risk for thromboembolism in severely obese.