Effects of changes in body weight and insulin resistance on inflammation and endothelial function in morbid obesity after bariatric surgery

Effects of Roux-en-Y gastric bypass on fasting and postprandial inflammation-related parameters in obese subjects with normal glucose tolerance and in obese subjects with type 2 diabetes

BACKGROUND

Obesity is characterized by low grade inflammation and an altered secretion of inflammatory cytokines from the adipose tissue. Weight loss has shown to reduce inflammation; however, changes in cytokine profiles during massive weight loss are not well described. The present study explored the hypothesis that Roux-en-Y gastric bypass (RYGB) reduces circulating levels of pro-inflammatory cytokines, while increasing anti-inflammatory cytokines in obese subjects with type 2 diabetes (T2D) and in obese normal glucose tolerant (NGT) subjects.

METHODS

Thirteen obese subjects with T2D [weight; 129 ± 14 kg, glycated hemoglobin (HbA1c); 7.0 ± 0.9%, body mass index (BMI); 43.2 ± 5.3 kg/m(2), mean ± SD] and twelve matched obese NGT subjects [weight; 127 ± 15 kg, HbA1c; 5.5 ± 0.4%, BMI; 41.5 ± 4.8 kg/m(2), mean ± SD] were examined before, one week, three months, and one year after surgery. Interleukin (IL)-6, leptin, adiponectin, IL-8, transforming growth factor beta (TGF-β), and the incretin hormone glucagon-like peptide-1 (GLP-1) were measured in the fasting state and during a liquid meal. Insulin resistance was evaluated by HOMA-IR.

RESULTS

Weight loss did not differ between the two groups. Before surgery, HbA1c was higher and HOMA-IR lower in T2D patients, however, converged to the values of NGT subjects one year after surgery. Circulating cytokine concentrations did not differ between the two groups at any time point. One week after surgery, circulating IL-6 and IL-8 were increased, while adiponectin and leptin were reduced compared with pre-surgical concentrations. Three months after surgery, IL-8 was increased, leptin was reduced, and no change was observed for IL-6, TGF-β, and adiponectin. One year after surgery, concentrations of IL-6, TGF-β, and leptin were significantly reduced compared to before surgery, while adiponectin was significantly increased.

CONCLUSIONS

One year after RYGB, fasting concentrations of IL-6 and leptin were reduced, while no changes were observed in IL-8. TGF-β was decreased and adiponectin increased in both T2D and NGT obese subjects. This study is the first to examine IL-8 and TGF-β in obese subject after RYGB. Resolution of inflammation could offer a potential explanation for the health improvement associated with major weight loss after bariatric surgery.

TRIAL REGISTRATION

http://www.clinicaltrials.gov (NCT01579981).

Baseline body mass index among children and adults undergoing allogeneic hematopoietic cell transplantation: clinical characteristics and outcomes

Obesity is an important public health problem that may influence the outcomes of hematopoietic cell transplantation (HCT). We studied 898 children and adults receiving first-time allogeneic hematopoietic SCTs between 2004 and 2012. Pretransplant body mass index (BMI) was classified as underweight, normal weight, overweight or obese using the WHO classification or age-adjusted BMI percentiles for children. The study population was predominantly Caucasian, and the median age was 51 years (5 months-73 years). The cumulative 3-year incidence of nonrelapse mortality (NRM) in underweight, normal weight, overweight and obese patients was 20%, 19%, 20% and 33%, respectively. Major causes of NRM were acute and chronic GVHD. The corresponding incidence of relapse was 30%, 41%, 37% and 30%, respectively. Three-year OS was 59%, 48%, 47% and 43%, respectively. Multivariate analysis showed that obesity was associated with higher NRM (hazard ratio (HR) 1.43, P=0.04) and lower relapse (HR 0.65, P=0.002). Pretransplant plasma levels of ST2 and TNFR1 biomarkers were significantly higher in obese compared with normal weight patients (P=0.04 and P=0.05, respectively). The increase in NRM observed in obese patients was partially offset by a lower incidence of relapse with no difference in OS.

Adhesion molecule increases in sleep apnea: beneficial effect of positive airway pressure and moderation by obesity

BACKGROUND

Elevated levels of intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) may contribute to cardiovascular disease and are associated with obstructive sleep apnea (OSA) and obesity. The relationship between OSA and obesity in determining ICAM-1 and VCAM-1 levels, and the effect of treatment, is unclear.

OBJECTIVE

Our aim was to study whether positive airway pressure (PAP) usage resulted in changes in ICAM-1 and VCAM-1 after 2 years within 309 OSA patients from the Icelandic Sleep Apnea Cohort, and determine how obesity affected such changes.

SUBJECTS/METHODS

The mean body mass index (BMI) was 32.4±5.1 kg m(-2); subjects had moderate-to-severe OSA (apnea-hypopnea index=45.0±20.2) and 79% were male. There were 177 full PAP users (⩾4 h per night and ⩾20 of last 28 nights), 44 partial (<4 h per night or <20 nights) and 88 nonusers.

RESULTS

ICAM-1 (P<0.001) and VCAM-1 (P=0.012) change was significantly different among the PAP groups. The largest ICAM-1 differences were among the most obese subjects (P<0.001). At follow-up, nonusers had increased ICAM-1 compared with decreased levels in full users. All groups had increased VCAM-1, but nonusers had a significantly larger increase than full users.

CONCLUSIONS

Within moderate-to-severe OSA patients, PAP usage prevents increases in adhesion molecules observed in nonusers after 2 years. For ICAM-1, the largest effect is in the most obese subjects. As OSA and obesity commonly coexist, the usage of PAP to limit increases in adhesion molecules may decrease the rate of progression of OSA-related cardiovascular disease.

Bacterial DNA translocation holds increased insulin resistance and systemic inflammatory levels in morbid obese patients

BACKGROUND

Morbidly obese patients show several common comorbidities associated with immunological alterations such as a sustained low-level proinflammatory profile. Bacterial product translocation is frequent in inflammation-related diseases and may aggravate patients' clinical outcome.

DESIGN

Consecutively admitted morbidly obese patients who presented indications for bariatric surgery were studied. Before surgery, patients were subjected to a modified fasting diet. Patients underwent surgery by sleeve gastrectomy or laparoscopic Roux-en-Y gastric bypass. Clinical and analytical parameters were recorded. Blood samples were collected at baseline, at the end of a 3-month modified fasting period, and 3, 6, and 12 months after surgery. Serum cytokine and endotoxin levels were evaluated by flow cytometry and ELISA, respectively. Bacterial DNA was identified in blood by broad-range PCR of prokaryote 16SrRNA gene and partial sequencing analysis.

RESULTS

Fifty-eight patients were included in the study. All patients showed a significantly reduced weight and body mass index at each time-point. Postoperative mortality was null. Bacterial DNA translocation rate was 32.8% (19 of 58) at baseline; 13.8% (8 of 58) after the modified fasting period; and 13.8% (8 of 58), 1.8% (1 of 58), and 5.2% (3 of 58) at 3, 6, and 12 months after surgery. Proinflammatory cytokines, serum endotoxin levels, and insulin resistance remained increased in patients with bacterial DNA despite weight loss and were individually affected by the appearance/clearance of bacterial DNA in blood. Multivariate analyses revealed bacterial DNA as an independent significant factor, explaining the systemic cytokine response and the insulin resistance levels in the studied population.

CONCLUSION

Bacterial DNA translocation holds increased insulin resistance and systemic inflammatory levels in morbidly obese patients despite significant weight loss.

C-reactive protein level in morbidly obese patients before and after bariatric surgery

BACKGROUND

Human obesity is associated with a proinflammatory state and an elevated level of mediators, such as C-reactive protein (CRP).

OBJECTIVES

To establish CRP levels as baseline preoperative values and then at 6 months after bariatric surgery, as well as to determine the changes in weight, body mass index (BMI), leukocytes, and glycemia.

MATERIALS AND METHODS

An observational, analytical, retrospective, longitudinal, and open study was conducted. Serum CRP values were measured in 36 adults presenting with morbid obesity, and their baseline relation to weight, BMI, leukocytes, and glycemia was determined; the relation to the same parameters was established again, 6 months after bariatric surgery.

RESULTS

The mean and standard deviation of preoperative and postoperative CRP (mg/L) was 1.15±0.86 and 0.34±0.28, respectively with p<0.0001; weight (kg) 112.10±22.91 and 84.82±17.11, p=0.0443; BMI (kg/m(2)) 42.48±5.97 and 32.2±4.79, p=0.0988; glucose (mg/dL) 100.58±17.82 and 87.11±8.49, p<0.0001, and leukocytes (× 10(3)/mm(3)) 8.62±1.69 and 6.99±1.56, p=0.3192. Baseline CRP only correlated with weight and BMI (p=0.047 and p=0.027 respectively) and there was no correlation between postoperative CRP and the evaluated parameters.

CONCLUSIONS

Preoperative CRP had a significant lineal relation to weight and body mass index. Patients who underwent bariatric surgery had a significant decrease in CRP, weight, and fasting glucose at 6 months after surgery.

Bariatric surgery and its impact on cardiovascular disease and mortality: a systematic review and meta-analysis

BACKGROUND

Bariatric surgery has been shown to improve cardiovascular risk factors but long term benefits for survival and cardiovascular events are still uncertain.

METHODS

We searched MEDLINE and EMBASE for parallel group studies that evaluated the clinical outcomes associated with bariatric surgery as compared to non-surgical treatment. Relevant studies were pooled using random effects meta-analysis for risk of myocardial infarction, stroke, cardiovascular events and mortality.

RESULTS

14 studies met the inclusion criteria, which included 29,208 patients who underwent bariatric surgery and 166,200 nonsurgical controls (mean age 48 years, 30% male, follow up period ranged from 2 years to 14.7 years). Four studies were considered at moderate-high risk of bias, whilst ten studies were at moderate or lower risk of bias. Compared to nonsurgical controls there was more than 50% reduction in mortality amongst patients who had bariatric surgery (OR 0.48 95% CI 0.35-0.64, I2=86%, 14 studies). In pooled analysis of four studies with adjusted data, bariatric surgery was associated with a significantly reduced risk of composite cardiovascular adverse events (OR 0.54 95% CI 0.41-0.70, I2=58%). Bariatric surgery was also associated with significant reduction in specific endpoints of myocardial infarction (OR 0.46 95% CI 0.30-0.69, I2=79%, 4 studies) and stroke (OR 0.49 95% CI 0.32-0.75, I2=59%, 4 studies).

CONCLUSIONS

Data from observational studies indicates that patients undergoing bariatric surgery have a reduced risk of myocardial infarction, stroke, cardiovascular events and mortality compared to non-surgical controls. Future randomized studies should investigate whether these observations are reproduced in a clinical trials setting.

Effects of weight loss and pharmacotherapy on inflammatory markers of cardiovascular disease

Obesity is currently an epidemic, and the prevalence of cardiovascular risk factors is increasing dramatically as a result. Visceral adiposity is correlated with a proinflammatory and prothrombotic state that is believed to promote atherosclerosis and acute coronary syndromes. This article will review clinical trials on the effects of weight loss and pharmacotherapy on obesity associated inflammatory and thrombotic markers linked with cardiovascular disease.

Changes in predicted cardiovascular disease risk after biliopancreatic diversion surgery in severely obese patients

OBJECTIVE

To determine the impact of biliopancreatic diversion with duodenal switch (BPD-DS) surgery on cardiovascular risk profile and predicted cardiovascular risk in severely obese patients.

MATERIALS/METHODS

We compared 1-year follow-up anthropometric and metabolic profiles in severely obese who underwent BPD-DS (n = 73) with controls (severely obese without surgery) (n =3 3). The 10-year predicted risk for coronary heart disease (CHD) was estimated using the Framingham risk-tool. We assigned 10-year and lifetime predicted risks to stratify subjects into 3 groups: 1) high short-term predicted risk (≥ 10% 10-year risk or diagnosed diabetes), 2) low short-term (<10% 10-year risk)/low lifetime predicted risk or 3) low short-term/high lifetime predicted risk.

RESULTS

During the follow-up period, body weight and body mass index decreased markedly in the surgical group (-52.1 ± 1.9 kg and -19.0 ± 0.6 kg/m(2) respectively, p<0.001) vs. (-0.7 ± 1.0 kg and -0.3 ± 0.4 kg/m(2), p = 0.51). Weight loss in the surgical group was associated with a reduction in HbA1C (6.2% vs. 5.1%), HOMA-IR (61.5 vs. 9.3), all lipoprotein levels, as well as blood pressure (p<0.001). The 10-year CHD predicted risk decreased by 43% in women and 33% in men, whereas the estimated CHD risk in the non surgical group did not change. Before surgery, none of the women and only 18% of men showed low short-term/low lifetime predicted risk, whereas a significant proportion of subjects had high short-term predicted risk (36% in women and 12% in men). Following surgery, 52% of women and 55% of men have a low short-term/low lifetime predicted risk.

CONCLUSIONS

These results highlight the cardiovascular benefits of BPD-DS and suggest a positive impact on predicted CHD risk in severely obese patients. Long-term studies are needed to confirm our results and to ascertain the effects on CHD risk estimates after BPD-DS surgery.

Can bariatric surgery reduce risk of Alzheimer's disease?

Recent studies demonstrate that obesity is independently associated with poor neurocognitive outcomes, including cognitive impairment, increased risk for dementia, and regional alterations in brain structure. Bariatric surgery is an effective treatment for obesity and initial findings suggest that it may result in cognitive improvements. The current paper reviews and integrates recent research in this area, with a focus on potential mediators and moderators of neuropsychological outcome in bariatric surgery patients, including anesthetic and nutritional complications, and proposes novel avenues for continued study in this area.

Gender effect on vascular responsiveness after bariatric surgery

Obesity, particularly abdominal obesity, is associated with increased risks of arterial hypertension, diabetes mellitus, hyperlipidemia, sleep apnea, coronary artery disease, stroke and mortality. Weight loss surgery is the most effective treatment for morbid obesity, mainly because medical and dietary treatments have been proven insufficient in the long run. Our primary end point was to study the gender effect on vascular responsiveness (endothelial function and the ankle brachial index [ABI]) 3 months post bariatric surgery. Our secondary end points were to study the effect of gender on antropometric parameters (BMI, waist circumference) and chronic diseases (diabetes mellitus type II, arterial hypertension) 3 months following bariatric surgery, and to find independent variables that may affect and predict the post-operative clinical outcome. Methods: In this prospective study, patients were evaluated one day before surgery and 3 months afterwards. Ankle brachial index was measured while the patient was supine after 15 minutes rest and measurement of the systolic blood pressure in all four extremities was done. The brachial artery method was used to measure endothelial function expressed as flow mediated diameter percent change (FMD %). FMD% more than 10% is considered a normal response. Results: Compared with diabetic females, diabetic males had a higher postoperative BMI (men with diabetes mellitus did not lose weight as much as diabetic women) (β=-0.299; P=0.04), while women with diabetes mellitus had a more significant reduction in BMI postoperatively (β=+0.287; P=0.04). Following bariatric surgery, 12 of the 21 patients with diabetes mellitus type II did not need any medications for diabetes (kept HbA1c% less than 6.5%). All other diabetic patients improved their diabetes mellitus status. Women significantly improved their ABI (average increase of 0.07, p=0.04) and their endothelial function (FMD% change was improved from -3.5±9.0% to 14.8±8.1%, an improvement of 18.3%, p<0.001). Systolic blood pressure was decreased significantly (by 6.6 mmHg, p=0.04). Men improved their endothelial function (FMD% change was improved from -1.3±10.1% to 11.7±6.2%, p<0.001), but no significant change was observed in systolic blood pressure (p=0.29) nor in ABI (P=0.8). A linear regression analysis found that a higher baseline FMD% significantly predicted a higher postoperative FMD% (β=0.294, P=0.03). In obese males, the higher the baseline BMI the worse the post operative endothelial function (β=-0.921, Pd<0.001) and the same adverse effect was documented for hypertensive men (β=-0.380, P=0.05). For females, the higher the baseline FMD% the higher the postoperative FMD% (β=+0.397; P=0.01) [a favorable outcome]. Discussion: Our study has demonstrated a possible mechanistic insight into gender effects observed in epidemiological studies through improvement in vascular response in females undergoing this operation including a better reduction in systolic blood pressure and a better weight reduction in diabetic women with improvement in ABI; unlike males, who did not improve their ABI and did not decrease systolic blood pressure, and the finding that obese diabetic males and obese hypertensive males did the worst.

Prolonged treatment with angiotensin 1-7 improves endothelial function in diet-induced obesity

OBJECTIVE

The renin-angiotensin system peptides are critically involved in the regulation of endothelial function with important pathological implications. Angiotensin (Ang) 1-7 has many beneficial effects in the vasculature that modulate the cardiovascular risk. Here, we tested the hypothesis that Ang 1-7 has a protective role against the endothelial defects associated with diet-induced obesity (DIO) in mice.

METHODS

Ang 1-7 (with or without Ang II) was delivered subcutaneously for 4 weeks using osmotic minipumps. Vascular studies were performed using aortic rings. Arterial pressure and heart rate were measured in separate cohorts of mice by telemetry.

RESULTS

First, we examined whether chronic administration of Ang 1-7 improves the vascular dysfunctions caused by Ang II. Subcutaneous coinfusion of Ang 1-7 significantly attenuates Ang II-induced endothelial dysfunctions. In addition, DIO mice have significant impairment in the endothelium-dependent relaxation. The contractile responses induced by various stimuli, including serotonin and endothelin-1, were differentially altered in DIO mice. Notably, DIO mice treated with Ang 1-7 for 4 weeks displayed significant improvement in the endothelial function as indicated by the increased acetylcholine-induced relaxation. Consistent with this, chronic treatment with Ang 1-7 reversed the increased aortic expression of NAD(P)H oxidase subunits (p22(phox) and p47(phox)) and plasma TBARS associated with DIO mice. In contrast, treatment with Ang 1-7 did not normalize the altered contractions associated with DIO mice.

CONCLUSION

Our data demonstrate a novel role for Ang 1-7 in improving obesity-associated endothelial dysfunction.

Obesity, diabetes and atrial fibrillation; epidemiology, mechanisms and interventions

The last few decades have witnessed a global rise in adult obesity of epidemic proportions. The potential impact of this is emphasized when one considers that body mass index (BMI) is a powerful predictor of death, type 2 diabetes (T2DM) and cardiovascular (CV) morbidity and mortality [1, 2]. Similarly we have witnessed a parallel rise in the incidence of atrial fibrillation (AF), the commonest sustained cardiac arrhythmia, which is also a significant cause of cardiovascular morbidity and mortality. Part of this increase is attributable to advances in the treatment of coronary heart disease (CHD) and heart failure (HF) improving life expectancy and consequently the prevalence of AF. However, epidemiological studies have demonstrated an independent association between obesity and AF, possibly reflecting common pathophysiology and risk factors for both conditions. Indeed, weight gain and obesity are associated with structural and functional changes of the cardiovascular system including left atrial and ventricular remodeling, haemodynamic alterations, autonomic dysfunction, and diastolic dysfunction. Moreover, diabetic cardiomyopathy is characterized by an adverse structural and functional cardiac phenotype which may predispose to the development of AF [3]. In this review, we discuss the pathophysiological and mechanistic relationships between obesity, diabetes and AF, and the challenges posed in the management of this high-risk group of individuals.

Clues from bariatric surgery: reversing insulin resistance to heal the heart

Obesity is a state of metabolic dysregulation of the whole organism and a major contributing factor to the epidemic of insulin resistant diabetes. The nonpharmacologic treatment of obesity with bariatric surgery results in a dramatic and almost instantaneous reversal of insulin resistance. The present review collectively addresses the evidence for this phenomenon in the literature and discusses potential metabolic and neurohumoral mechanisms. We propose that nutrient restriction lowers the cell's defense mechanisms for nutrient overload in insulin responsive organs.

Potential mechanisms by which bariatric surgery improves systemic metabolism

Over the past several decades, excessive body weight has become a major health concern. As the obesity epidemic continues to expand, metabolic disorders associated with excess body weight, including type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease, have exponentially increased. Dysregulation of satiety hormones and factors that regulate long-term energy storage can disrupt normal metabolic functions and lead to excess body fat. While diet and exercise seem to provide a logical means for weight loss, an unhealthy lifestyle coupled to responses initiated by perceived energy deficit impede sustained long term weight loss. Furthermore, because of the additional lack of effective pharmaceutical interventions to treat excess body weight, patients with severe obesity resort to bariatric surgery as an effective alternative for treatment of obesity and resolution of its associated comorbidities. Interestingly, the precise method by which bariatric surgery promotes rapid improvement in systemic metabolism and long-term weight loss remains incompletely understood and may vary between procedures. Multiple mechanisms likely contribute to the improved glucose metabolism seen after bariatric surgery, including caloric restriction, changes in the enteroinsular axis, alterations in the adipoinsular axis, release of nutrient-stimulated hormones from endocrine organs, stimulation from the nervous system, and psychosocial aspects including a dramatic improvement in quality of life. The current review will highlight the potential contribution of these responses to the improvement in systemic energy metabolism elicited by bariatric surgery.

Reduced cardiovascular risk after bariatric surgery is linked to plasma ceramides, apolipoprotein-B100, and ApoB100/A1 ratio

BACKGROUND

Obesity-associated hyperlipidemia and hyperlipoproteinemia are risk factors for cardiovascular disease (CVD). Recently, ceramide-derived sphingolipids were identified as a novel independent CVD risk factor. We hypothesized that the beneficial effect of Roux-en-Y gastric bypass (RYGB) on CVD risk is related to ceramide-mediated improvement in lipoprotein profile.

METHODS

A prospective study of patients undergoing RYGB was conducted. The patients' clinical data and biochemical markers related to cardiovascular risk were documented. Plasma ceramide subspecies (C14:0, C16:0, C18:0, C18:1, C20:0, C24:0, and C24:1), apolipoprotein (Apo)B100 and ApoA1 were quantified preoperatively and 3 and 6 months after RYGB, as was the Framingham risk score. Brachial artery reactivity testing was performed before and 6 months after RYGB.

RESULTS

Ten patients (9 women; age 48.6 ± 9.6 yr; body mass index, 48.5 ± 5.8 kg/m(2)) were included in the present study. At 6 months postoperatively, the mean body mass index had decreased to 35.7 ± 5.0 kg/m(2), corresponding to 51.3% ± 10.0% excess weight loss. The fasting total cholesterol, triglycerides, low-density lipoprotein, free fatty acids, ApoB100, ApoB100/ApoA1 ratio and insulin resistance estimated from Homeostasis Model of Assessment of Insulin Resistance were significantly reduced compared with the preoperative values. The ApoB100/ApoA1 ratio correlated with a reduction in ceramide subspecies (C18:0, C18:1, C20:0, C24:0, and C24:1; P < .05). ApoB100 and the ApoB100/ApoA1 ratio also correlated positively with the reduction in triglycerides, low-density lipoprotein, and Homeostasis Model of Assessment of Insulin Resistance (P < .05). Brachial artery reactivity testing correlated inversely with ApoB100 and total ceramide (P = .05). Furthermore, the change in brachial artery reactivity testing correlated with the decrease in C16:0 (P < .03).

CONCLUSION

Our data suggest that improvements in lipid profiles and CVD risk factors after gastric bypass surgery could be linked to changes in ceramide lipids. Mechanistic studies are needed to determine whether this link is causative or purely correlative.

Effects of bariatric surgery on adipokine-induced inflammation and insulin resistance

Over a third of the US population is obese and at high risk for developing type 2 diabetes, insulin resistance, and other metabolic disorders. Obesity is considered a chronic low-grade inflammatory condition that is primarily attributed to expansion and inflammation of adipose tissues. Indeed, adipocytes produce and secrete numerous proinflammatory and anti-inflammatory cytokines known as adipokines. When the balance of these adipokines is shifted toward higher production of proinflammatory factors, local inflammation within adipose tissues and subsequently systemic inflammation occur. These adipokines including leptin, visfatin, resistin, apelin, vaspin, and retinol binding protein-4 can regulate inflammatory responses and contribute to the pathogenesis of diabetes. These effects are mediated by key inflammatory signaling molecules including activated serine kinases such as c-Jun N-terminal kinase and serine kinases inhibitor κB kinase and insulin signaling molecules including insulin receptor substrates, protein kinase B (PKB, also known as Akt), and nuclear factor kappa B. Bariatric surgery can decrease body weight and improve insulin resistance in morbidly obese subjects. However, despite reports suggesting reduced inflammation and weight-independent effects of bariatric surgery on glucose metabolism, mechanisms behind such improvements are not yet well understood. This review article focuses on some of these novel adipokines and discusses their changes after bariatric surgery and their relationship to insulin resistance, fat mass, inflammation, and glucose homeostasis.

Obesity and inflammation: change in adiponectin, C-reactive protein, tumour necrosis factor-alpha and interleukin-6 after bariatric surgery

BACKGROUND

Obesity is associated with a low-grade inflammatory state. A causal association between inflammation and atherosclerosis has been suggested. The aim of this study was to evaluate changes in the proinflammatory profile of morbidly obese patients after weight loss following bariatric surgery.

METHODS

In this study, we measured levels of adiponectin, high-sensitivity C-reactive protein (hs-CRP), tumour necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6) and their relation to insulin resistance and lipid parameters in 60 morbidly obese women at baseline and 3, 6 and 12 months after gastric bypass.

RESULTS

Twelve months after surgery, there was a significant increase in plasma levels of adiponectin (p < 0.001) and high-density lipoprotein cholesterol (p < 0.01) and a significant decrease in levels of IL-6 (p < 0.001), hs-CRP (p < 0.001), cholesterol (p < 0.001), triglycerides (p < 0.001), low-density lipoprotein cholesterol (p < 0.001), glucose (p < 0.001), insulin (p < 0.001) and homeostasis model assessment (HOMA; p < 0.001). At 12 months, correlations were seen between IL-6 levels and the following: body mass index (BMI) (r = 0.53, p < 0.001), insulin (r = 0.51, p < 0.001) and HOMA (r = 0.55, p < 0.001). Also, hs-CRP levels correlated with BMI (r = 0.40, p = 0. 004), triglycerides (r = 0.34, p = 0.017), insulin (r = 0.50, p = 0.001) and HOMA (r = 0.46, p = 0.002).

CONCLUSIONS

In patients with morbid obesity, significant weight loss is followed by a significant improvement in the inflammatory state, insulin sensitivity and lipid profile. A relationship exists between improved inflammatory profile and insulin sensitivity.

Glucagon-like peptide-1 analogue therapy for psoriasis patients with obesity and type 2 diabetes: a prospective cohort study

BACKGROUND

Diabetes and obesity are more prevalent amongst psoriasis patients as is disturbance of the innate immune system. GLP-1 analogue therapy considerably improves weight and glycaemic control in people with type 2 diabetes and its receptor is present on innate immune cells.

OBJECTIVE

We aimed to determine the effect of liraglutide, a GLP-1 analogue, on psoriasis severity.

METHODS

Before and after 10 weeks of liraglutide therapy (1.2 mg subcutaneously daily) we determined the psoriasis area and severity index (PASI) and the dermatology life quality index (DLQI) in seven people with both psoriasis and diabetes (median age 48 years, median body mass index 48.2 kg/m(2) ). We also evaluated the immunomodulatory properties of liraglutide by measuring circulating lymphocyte subset numbers and monocyte cytokine production.

RESULTS

Liraglutide therapy decreased the median PASI from 4.8 to 3.0 (P = 0.03) and the median DLQI from 6.0 to 2.0 (P = 0.03). Weight and glycaemic control improved significantly. Circulating invariant natural killer T (iNKT) cells increased from 0.13% of T lymphocytes to 0.40% (P = 0.03). Liraglutide therapy also effected a non-significant 54% decrease in the proportion of circulating monocytes that produced tumour necrosis factor alpha (P = 0.07).

CONCLUSION

GLP-1 analogue therapy improves psoriasis severity, increases circulating iNKT cell number and modulates monocyte cytokine secretion. These effects may result from improvements in weight and glycaemic control as well as from direct immune effects of GLP-1 receptor activation. Prospective controlled trials of GLP-1 therapies are warranted, across all weight groups, in psoriasis patients with and without type 2 diabetes.

Effect of weight loss on C3 and C4 components of complement in obese patients

BACKGROUND

Circulating C3 levels are elevated in obese patients, but how this factor is affected after weight loss through diet is a question that is yet unanswered. Therefore, the aim of this study was to evaluate the effects of weight loss on lipid and hydrocarbonated metabolism parameters and on the levels of C3 and C4 components of complement in obese patients.

DESIGN

This is a longitudinal intervention study based on a 6-week very low-calorie diet (VLCD), a liquid formula of 603 kcal/day. A total of 131 middle-aged patients were distributed among grades II, III and IV of obesity. Anthropometric parameters, total cholesterol, triglycerides, high-density lipoprotein cholesterol, LDLc, apolipoproteins A-I and B-100, glucose, insulin, HOMA-IR and C3 and C4 levels were evaluated at baseline and after 6 weeks of intervention.

RESULTS

After VLCD, the moderate weight loss was accompanied by a significant reduction in C3 levels in grade III and grade IV patients (10.2% and 15.4%, respectively; P < 0.001). C4 levels were not altered. Adherence to the diet improved anthropometric parameters and was accompanied by a significant decrease in all lipid profile parameters (P < 0.001). In addition, weight loss was associated with an improvement in hydrocarbonated metabolism as shown by the decrease in glucose levels and HOMA-IR (P < 0.01).

CONCLUSIONS

Our findings show that in severely obese patients following a VLCD for 6 weeks produces reductions in factor C3, a biomarker of cardiovascular disease, and a significant improvement in some features of metabolic syndrome. In this way, the abovementioned diet may represent an effective strategy for treating obesity and related cardiovascular risk factors.

Plasminogen activator inhibitor 1 and visceral obesity during pronounced weight loss after bariatric surgery

BACKGROUND AND AIMS

Elevated plasminogen activator inhibitor 1 (PAI-1) concentrations are a hallmark of obesity and are considered to contribute to the development of cardiovascular disease. As adipose tissue constitutes a major source for PAI-1 in obesity, we investigated the individual contribution of subcutaneous and intra-abdominal fat on PAI-1 concentrations during pronounced weight loss after bariatric surgery.

METHODS AND RESULTS

Thirty-seven obese adults were examined before and 18 months after surgery. Abdominal fat distribution was determined by ultrasound, metabolic parameters and plasma PAI-1 levels by standard methods. BMI was reduced by 9.2 ± 4.9 kg/m(2), while total fat mass and visceral fat diameter (VFD) decreased by 20.7 ± 11.9 kg and 4.2 ± 2.3 cm, respectively. Concomitantly, PAI-1 levels diminished by 3.2 ± 5.6 ng/ml (all p ≤ 0.015). Change in PAI-1 levels was correlated with change in VFD (r = 0.441, p = 0.008), but not with subcutaneous fat diameter. In stepwise multiple regression analysis change in VFD was an independent predictor of change in PAI-1 concentrations. When adjusted for age and sex or total fat mass associations between PAI-1 and VFD remained significant.

CONCLUSION

We demonstrate that VFD is a major determinant for PAI-1 concentrations during pronounced weight loss after bariatric surgery. Thus, significant reduction of visceral fat mass may contribute to the reduced cardiovascular morbidity and mortality after bariatric surgery by a concomitant decrease in PAI-1 concentrations.

Insulin resistance and bariatric surgery

The objective of this article is to systematically review the changes in insulin resistance after various types of bariatric surgical procedures. A Pubmed and EMBASE search for studies measuring insulin resistance before and after bariatric surgery was done and all original research articles from 1980 to present (2011) were included. Only the currently widely performed bariatric procedures were included. A meta-analysis of change in HOMA-IR was conducted, grouping studies with similar duration of follow-up. The percentage decrease in HOMA-IR at <=2 weeks, 1 month, 3 months, 6 months, 12 months and >16-18 months was found to be (mean ± standard error) -33.48 ± 5.78, -46.43 ± 6.99, -38.79 ± 9.64, -58.62 ± 7.38, -44.91 ± 7.98 and -67.04 ± 10.78%, respectively. RYGB (gastric bypass) and BPD (biliopancreatic diversion) produced a significant decrease in insulin resistance at 2 weeks after surgery, while LSG (sleeve gastrectomy) was strongly trending. LSG produced an earlier decrease in insulin resistance when compared to LAGB (gastric banding). RYGB, BPD and LSG produce an early decrease in insulin resistance through yet unknown mechanisms.

Reduced cardiovascular risk following bariatric surgeries is related to a partial recovery from "adiposopathy"

BACKGROUND

Altered cytokine secretion from dysfunctional adipose tissue or "adiposopathy" is implicated in obesity related inflammation and may mediate reduced cardiovascular disease (CVD) risk in response to weight loss after bariatric surgery. We hypothesized that bariatric surgery reduces CVD risk by favorably altering the pro-inflammatory profile of adipose tissue as a result of weight loss.

METHODS

In this observational study with repeated measures, 142 patients underwent bariatric surgery of which 45 returned for follow-up at ∼6 months. At both time-points, lipid profiles and levels of plasma adiponectin, leptin, and TNF-α were obtained. Ratios of various adipokine parameters were related to pre- and post- surgical (gastric bypass vs. other restrictive bariatric procedures) lipid ratios.

RESULTS

Prior to surgery, circulating adiponectin and the adiponectin/TNF-α ratio was strongly associated with CVD risk characterized by levels of triglycerides, HDL, and the TC/HDL, LDL/HDL, and TG/HDL ratios (all P < 0.05). Following bariatric surgery, BMI was decreased by 22%, adiponectin was increased by 93%, and leptin decreased by 50% as compared to baseline (all P < 0.01). TNF-α levels increased by 120% (P < 0.01) following surgery. Post-surgical changes in adiponectin and the leptin/adiponectin ratio were strongly associated with incremental improvements in triglycerides, HDL, and TC/HDL, LDL/HDL and TG/HDL ratios (all P < 0.05). Roux-en-y gastric bypass surgery (RYGB) as compared to other bariatric procedures was associated with more robust improvements in BMI, HDL, and leptin/adiponectin ratio than other gastric restrictive procedures (P < 0.05).

CONCLUSIONS

Thus, bariatric surgery, especially RYGB, ameliorates CVD risk through a partial recovery from "adiposopathy", distinctively characterized by improved adiponectin and the leptin/adiponectin ratio.

Post-prandial endothelial dysfunction is ameliorated following weight loss in obese premenopausal women

Background

Endothelial dysfunction and postprandial hyperglycemia represent independent risk factors for cardiovascular diseases. Obesity is connected with endothelial impairments; however, it is unclear whether weight loss can modify endothelial function during the postprandial period. The aim of this study was to evaluate endothelial response (post-ischemic forearm blood flow, PIFBF) in a fasted state and following ingestion of 75g glucose before and after very low caloric diet (VLCD).

Material/Methods

40 obese premenopausal women (age 39.6±7.8 years, BMI 34.3±3.2 kg/m²) participated in 4-week very low caloric diet (VLCD, 800kcal/day). Before and after VLCD, the baseline blood flow and PIFBF were measured using a mercury strain gauge plethysmography in fasting state as well as 1 hour after ingestion of 75 g glucose.

Results

Dietary intervention resulted in a 7% weight loss (p<0.05) and a decrease in insulin resistance index HOMA-IR (2.44±1.25 vs. 1.66±0.81, p<0.05). Before VLCD intervention, PIFBF following oral glucose challenge decreased by 8.2±9.1 ml/min/100 g tissue, while after weight loss identical stimulus increased PIFBF by 4.2±8.9 ml/min/100 g tissue (p<0.05). Plasma ICAM-1 and VCAM-1 decreased by 8% and 10%, respectively, throughout the study.

Conclusions

Postprandial endothelial dysfunction is ameliorated following weight loss in obese women. This finding demonstrates the beneficial effects of weight reduction on atherosclerosis risk.

Longitudinal evaluation of cancer-associated biomarkers before and after weight loss in RENEW study participants: implications for cancer risk reduction

INTRODUCTION

Obesity is a major risk factor for the development of endometrial cancer (EC). An improved understanding of biologic mechanisms associated with weight loss, including alteration in inflammation, hormonal balance, and cancer antigens expression may lead to the development of effective cancer prevention strategies. The goal of this study was to explore longitudinal biomarker changes in obese women who underwent weight loss intervention, testing the hypothesis biomarker levels can be altered through intentional weight loss.

METHODS

Serum samples from 89 participants with Class II and Class III obesity and 43 non morbidly obese comparisons were obtained in Re-Energize with Nutrition, Exercise and Weight Loss (RENEW) study as previously reported. Twenty-one bead-based xMAP immunoassays were utilized, including cancer-associated antigens, cytokines, chemokines, and hormones. One-way repeated measures ANOVA was used to examine the association between changes in biomarker expression levels over time (baseline, 6 months and 12 months). Linear mixed effects models were used to examine longitudinal relationships between biomarker expression levels.

RESULTS

Mean levels of VEGF, soluble E-selectin, GH, adiponectin, IL-6, IL-7, CA-125, and IGFBP-1 significantly differed between time periods. In adjusted mixed linear models, decreasing BMI was significantly associated with lower levels of soluble E-selectin and IL-6 and increases in GH, adiponectin, and IGFBP-1.

CONCLUSIONS

This is one of the first efforts to explore changes in cancer-associated biomarkers in a cohort of weight loss research participants at high risk for EC development. Our findings demonstrate that changes in the expression of markers can be achieved with weight loss intervention.

Does intentional weight loss reduce cancer risk?

Epidemiologic evidence points to obesity as a major risk factor for many cancers, including cancers of the breast, endometrium, colorectum, kidney, oesophagus and pancreas. Whether intentional weight loss might reduce this excess risk is not yet proven. We searched the medical literature for studies reporting changes in cancer risk following intentional weight loss, and for studies reporting changes in cancer-relevant risk factors of oestrogens, sex hormone binding globulin (SHBG), Insulin-like growth factor-I (IGF-I), IGF binding proteins and selected inflammatory markers [C-reactive protein (CRP), interleukin 6 (IL-6) and tumour necrosis factor-α (TNF-α)]. Observational cohort studies and randomized controlled trials of both dietary interventions and bariatric surgery all indicate fairly immediate reductions in cancer incidence following intentional weight loss. Oestrogen levels drop and SHBG levels increase coincident with intentional weight loss, with about a one-third reduction in free oestradiol to be expected from a 10% weight loss. CRP levels also drop substantially after weight loss at about this same 3 : 1 ratio. Reductions in TNF-α and IL-6 are consistently seen, but of a smaller magnitude, and IGF-I and IGFBP changes after weight loss are small and inconsistent. Because both cancer incidence and levels of circulating cancer biomarkers drop fairly rapidly following weight loss, intentional weight loss may well lead to meaningful reductions in cancer risk with a short latency time.

Temporal changes in glucose and insulin homeostasis after biliopancreatic diversion and laparoscopic adjustable gastric banding

BACKGROUND

Obesity surgery is associated with improvement in type 2 diabetes mellitus. Our aim was to examine the effects of biliopancreatic diversion (BPD) and laparoscopic adjustable gastric banding (LAGB) on the body mass index, fasting insulin level, glucose level, and insulin resistance in morbidly obese subjects with type 2 diabetes mellitus. The setting was the Department of Surgery, Morriston Hospital (Swansea, Wales, United Kingdom).

METHODS

A total of 13 morbidly obese patients (7 BPD, 6 LAGB) underwent serial measurements of fasting glucose and insulin at baseline, immediately after surgery (days 1-7), and 1, 6, and 12 months postoperatively. The homeostasis model of assessment-insulin resistance was calculated.

RESULTS

In the BPD group, the glucose levels had normalized by day 3 (5.6 ± 1 mmol/L) and the difference was statistically significant at 6 and 12 months postoperatively (5 ± .7 and 4.4 ± .5 mmol/L, respectively). The insulin levels had improved from day 1, and the difference was statistically significant at days 2, 5, 6, and 7 (19 ± 9, 14.2 ± 7, 15.2 ± 8, and 17.4 ± 8 mU/L, respectively). All diabetes medications were stopped on the fourth postoperative day. In the LAGB group, no statistically significant changes were seen in the glucose levels. Statistically significant changes in insulin were seen on days 1 and 2 (19 ± 13 and 13 ± 6.5 mU/L, respectively). The homeostatic model of assessment-insulin resistance had improved in both groups (BPD, 1.6 ± 1.2, P < .01; and LAGB, 4.3 ± 1.4, P < .05).

CONCLUSION

BPD causes immediate remission of type 2 diabetes mellitus. Leptin might play an important role in the early improvement of insulin resistance in fasting states after BPD. In the LAGB group, glucose homeostasis improved, but the patients still required diabetes medications, although the dosages were reduced.

Gastric bypass surgery reduces plasma ceramide subspecies and improves insulin sensitivity in severely obese patients

Bariatric surgery is associated with near immediate remission of type 2 diabetes and hyperlipidemia. The mechanisms underlying restoration of normal glucose tolerance postoperatively are poorly understood. Herein, we examined the effect of Roux-en-Y gastric bypass surgery (RYGB) on weight loss, insulin sensitivity, plasma ceramides, proinflammatory markers, and cardiovascular risk factors before and at 3 and 6 months after surgery. Thirteen patients (10 female; age 48.5 ± 2.7 years; BMI, 47.4 ± 1.5 kg/m(2)) were included in the study, all of whom had undergone laparoscopic RYGB surgery. Insulin sensitivity, inflammatory mediators and fasting lipid profiles were measured at baseline, 3 and 6 months postoperatively, using enzymatic analysis. Plasma ceramide subspecies (C14:0, C16:0, C18:0, C18:1, C20:0, C24:0, and C24:1) were quantified using electrospray ionization tandem mass spectrometry after separation with HPLC. At 3 months postsurgery, body weight was reduced by 25%, fasting total cholesterol, triglycerides, low-density lipoproteins, and free fatty acids were decreased, and insulin sensitivity was increased compared to presurgery values. These changes were all sustained at 6 months. In addition, total plasma ceramide levels decreased significantly postoperatively (9.3 ± 0.5 nmol/ml at baseline vs. 7.6 ± 0.4 at 3 months, and 7.3 ± 0.3 at 6 months, P < 0.05). At 6 months, the improvement in insulin sensitivity correlated with the change in total ceramide levels (r = -0.68, P = 0.02), and with plasma tumor necrosis factor-α (TNF-α) (r = -0.62, P = 0.04). We conclude that there is a potential role for ceramide lipids as mediators of the proinflammatory state and improved insulin sensitivity after gastric bypass surgery.

Inflammatory cytokine profiles during exercise in obese, diabetic, and healthy children

OBJECTIVE

Modulation of inflammatory status is considered a key component of the overall health effects of exercise. This may be especially relevant in children with obesity (Ob) or type 1 diabetes (T1DM), in which an imbalance between pro- and anti-inflammatory mediators could accelerate onset and progression of cardiovascular complications. To date, exercise-induced alterations in immuno-modulatory mediators in Ob and T1DM children remain largely unknown.

METHODS

In this study, we monitored the kinetic profiles of 8 pro-and anti-inflammatory cytokines (TNF-a, IL-6, IL-2, IL-8, IL-5, IL-13, IL-10, IL-4) during a standardized exercise challenge (ten 2-min cycling bouts at 80% VO2max, separated by 1-min intervals) in 23 Ob (12 females, 11 males), 23 T1DM (10 females and 13 males) patients and 20 healthy (CL, 10 females and 10 males) children. Blood glucose of T1DM patients was kept in the 4.4-6.1 mM range for at least 90 minute prior to and during exercise. Blood samples were drawn at rest and after every other exercise bout.

RESULTS

In Ob, TNF-a and IL-2 were significantly greater (p<0.0167) as compared to T1DM and CL, both at baseline and throughout exercise. All other variables, while not significant, were quantitatively elevated in Ob vs. CL. In T1DM, IL-4 and IL-8 levels were similar to Ob, IL-2 and TNF-a similar to CL, and IL-6, IL-5, IL-13, IL-4 levels were intermediate between the Ob and CL groups.

CONCLUSIONS

During exercise, therefore, both Ob and T1DM children displayed exaggerated pro-inflammatory responses, although with clearly different magnitude and involved mediators. Our data support the necessity to identify specific exercise formats through which each at-risk pediatric population can draw maximal beneficial health effects.

Trace element status and inflammation parameters after 6 months of Roux-en-Y gastric bypass

BACKGROUND

Knowledge about the practical consequences of the nutritional status of Fe, Zn, and Cu and inflammation in obesity is limited. The objective of this study was to evaluate changes on trace element status and their potential associations with selected inflammation parameters in patients after Roux-en-Y gastric bypass (RYGBP).

METHODS

Sixty-three women (mean age, 36.9 ± 9.2 years, body mass index, 43.8 ± 4.3 kg/m²) were evaluated at baseline and 6 months after RYGBP. Anthropometric (weight, waist circumference), body composition (fat mass and fat-free mass), dietary (nutrient intakes), and metabolic and inflammation (glucose, insulin, HOMA-IR, adiponectin, HDL-cholesterol, LDL-cholesterol, triglycerides, hs-CRP, leukocytes, polymorphonuclear neutrophils (PMN)) parameters were determined in addition to selected indices of Fe, Zn, and Cu status.

RESULTS

All but one (HDL-cholesterol) metabolic and inflammation parameters had significant differences when compared before and after RYGBP. Hemoglobin, serum ferritin, the size of the rapidly exchangeable zinc pool, and plasma copper decreased after RYGBP. Plasma and hair zinc, as well as zinc protoporphyrin increased. The change in Hb was significantly associated (p < 0.05) to the change in leukocytes (r = 0.33) and adiponectin (r = -0.44). Zinc protoporphyrin change was associated to the change in PMN (r = 0.32) and HDL-cholesterol (r = -0.29). No other associations between the changes of the rest of Fe, Zn, and Cu parameters with the changes of any of the metabolic and inflammation parameters were observed.

CONCLUSION

RYGBP produced significant weight and fat mass losses, with improvement of metabolic and inflammation parameters. Iron, zinc, and copper status were impaired after the surgery.

Bariatric surgery reduces visceral adipose inflammation and improves endothelial function in type 2 diabetic mice

OBJECTIVE

Bariatric surgery is emerging as an effective method to alleviate a multitude of medical conditions associated with morbid obesity and type 2 diabetes. However, little is known about the effects and mechanisms of bariatric surgery on visceral fat inflammation and endothelial dysfunction in type 2 diabetes. We hypothesize that bariatric surgery ameliorates interferon-γ-mediated adipose tissue inflammation/oxidative stress and improves endothelial function in type 2 diabetic mice.

METHODS AND RESULTS

Control mice (m Lepr(db)) and diabetic mice (Lepr(db)) were treated with either sham surgery or improved gastric bypass surgery and then were evaluated at 5, 10, 20, and 30 days to assess postsurgical effects. Surgery reduced body weight, abdominal adiposity, blood glucose level, and food intake in Lepr(db). The surgery-induced decrease in visceral adiposity was accompanied by amelioration of T-lymphocytes and macrophage infiltration, as well as reduction in the expression of interferon-γ and other inflammatory cytokines in the mesenteric adipose tissue (MAT) of Lepr(db) mice. Furthermore, surgery improved endothelium-dependent, but not endothelium-independent, vasorelaxation in small mesenteric arteries (SMA) of Lepr(db) mice. The improvement in endothelial function was largely attenuated by nitric oxide synthase inhibitor (L-NAME) incubation. Interferon-γ treatment increased the mRNA expression of tumor necrosis factor-α in the MAT of control mice and incubation of SMA of control mice with tumor necrosis factor-α caused impairment of endothelial function. Superoxide production in MAT/SMA and nitrotyrosine protein level in SMA were elevated in diabetic mice. Surgery reduced MAT/SMA oxidative stress in Lepr(db) mice.

CONCLUSIONS

The amelioration of adipose tissue inflammation and the improvement of endothelial function may represent important mechanisms that result in cardiovascular benefits after bariatric surgery.

Endothelial biology in the post-menopausal obese woman

Women generally have a reduced risk of cardiovascular disease (CVD). However, this protection of gender diminishes rapidly after menopause and with advancing age, particularly in obese women. Alterations in vascular function are thought to a key early step in the development of atherosclerosis. In this review, we will describe the features of endothelial dysfunction in the post-menopausal obese female and discuss the interplay of aging, estrogen withdrawal, and obesity. The objectives include (1) a review of endothelial biology and endothelial dysfunction, and (2) a discussion how the endothelial function is altered in the context of aging, hormonal changes and insulin resistance. The clinical consequences of endothelial dysfunction and CVD will also be reviewed.

Obesity, weight loss and conditional cardiovascular risk factors

Obesity is a pathological condition aggregating a substantial number of proatherogenic factors, such as insulin resistance, type 2 diabetes mellitus, dyslipidaemia and hypertension. In addition to these classic cardiometabolic risk factors, atherosclerosis may be aggravated by other non-classic factors, which are characterized as conditional, including homocysteine, fibrinogen, lipoprotein(a), LDL particle size and high-sensitivity CRP. Some of these biomarkers are disturbed in obesity because of a combination of dietary factors, hypertrophic adipose tissue, low-grade inflammation, insulin resistance and other parameters under investigation. For the reduction of these risk factors, weight loss exceeding 10-20% of the initial body weight is probably necessary, achieved through either conventional lifestyle measures or more drastic interventions such as bariatric surgery. It has been shown that certain well-balanced diets, such as the Mediterranean diet, constitute a means of improving in a concerted manner the levels of CRP, fibrinogen, homocysteine and small dense LDL particles, regardless of weight loss. The significance of considering these factors in weight management intervention is an issue that needs further investigation.

Diabetes resolution and hyperinsulinaemia after metabolic Roux-en-Y gastric bypass

The global prevalence of type 2 diabetes mellitus and impaired glucose metabolism continues to rise in conjunction with the pandemic of obesity. The metabolic Roux-en-Y gastric bypass operation offers the successful resolution of diabetes in addition to sustained weight loss and excellent long-term outcomes in morbidly obese individuals. The procedure consists of the physiological BRAVE effects: (i) Bile flow alteration; (ii) Reduction of gastric size; (iii) Anatomical gut rearrangement and altered flow of nutrients; (iv) Vagal manipulation and (v) Enteric gut hormone modulation. This operation provides anti-diabetic effects through decreasing insulin resistance and increasing the efficiency of insulin secretion. These metabolic outcomes are achieved through weight-independent and weight-dependent mechanisms. These include the foregut, midgut and hindgut mechanisms, decreased inflammation, fat, adipokine and bile metabolism, metabolic modulation, shifts in gut microbial composition and intestinal gluconeogenesis. In a small minority of patients, gastric bypass results in hyperinsulinaemic hypoglycaemia that may lead to nesidioblastosis (pancreatic beta-cell hypertrophy with islet hyperplasia). Elucidating the precise metabolic mechanisms of diabetes resolution and hyperinsulinaemia after surgery can lead to improved operations and disease-specific procedures including 'diabetes surgery'. It can also improve our understanding of diabetes pathogenesis that may provide novel strategies for the management of metabolic syndrome and impaired glucose metabolism.

The effects of an amino acid supplement on glucose homeostasis, inflammatory markers, and incretins after laparoscopic gastric bypass

BACKGROUND

Protein supplements are routinely used after a laparoscopic gastric bypass (LGB). The aim of this study was to evaluate the impact of an amino acid supplement on glucose homeostasis and hormonal and inflammatory markers after LGB.

STUDY DESIGN

Thirty patients undergoing LGB were randomized to receive or not 24 g of an oral supplement containing a leucine metabolite, glutamine, and arginine twice daily. Changes in weight, glucose, insulin, C-peptide, insulin sensitivity, interleukin (IL) 6, C-reactive protein (CRP), leptin, insulin-like growth factor (IGF) 1, ghrelin, and incretins were assessed preoperatively and 2 weeks and 8 weeks postoperatively.

RESULTS

Thirty patients (96.7% female, age 46.9 ± 8.4 years, body mass index 43.3 ± 4.1 kg/m(2)) were randomized. The experimental (n = 14) and control (n = 16) groups were not significantly different at baseline. Weight loss was similar for the 2 groups. Fasting glucose decreased significantly at 2 and 8 weeks compared with base line (p < 0.0001) with no difference between the experimental and control groups (p = 0.8), but insulin and calculated insulin sensitivity, which were similar at baseline, became significantly worse in the experimental group 8 weeks after surgery (p = 0.02 for insulin; p = 0.04 for the homeostasis model assessment of insulin resistance). CRP and IL-6, which were similar at baseline, were found to be significantly higher at 8 weeks in the experimental group (p = 0.018 and p = 0.05, respectively). Leptin and IGF-1 levels decreased significantly from baseline at 2 and 8 weeks (p < 0.0001), but there was no difference between the 2 groups. No significant changes in GLP-1, ghrelin, or gastric inhibitory polypeptide were noticed after 8 weeks.

CONCLUSIONS

An amino acid supplement had no effect on the early postoperative incretins after LGB. It may have a negative influence on glucose kinetics and degree of inflammation. Future studies are needed to clarify these effects.

Early effects of gastric bypass on endothelial function, inflammation, and cardiovascular risk in obese patients

BACKGROUND

Obesity is associated with a chronic low-grade inflammatory state, insulin resistance, and endothelial dysfunction, all of which contribute to increased risk of cardiovascular disease. We hypothesized that gastric bypass would produce rapid improvements in endothelial function, reduce inflammation, and lead to a decrease in cardiovascular risk.

METHODS

We performed a prospective study of morbidly obese patients who underwent laparoscopic Roux-en-Y gastric bypass (RYGB). Clinical data, biochemical markers of inflammation, and parameters indicative of cardiovascular risk were collected preoperatively and at 3 and 6 months postoperatively. Metabolic and inflammatory mediators that were quantified included C-reactive protein, fibrinogen, PAI-1, IL-6, IL-10, IL-1Ra, adiponectin, leptin, triglycerides, total cholesterol, HDL, LDL, glucose, insulin, and HbA1c. Brachial artery reactivity testing (BART) was performed to assess peripheral arterial endothelial function, and Framingham cardiovascular risk score (FRS) was calculated on all study participants pre- and postoperatively.

RESULTS

Fifteen patients (11 female) were enrolled (age = 49.2 ± 10.4 years; BMI = 48.1 ± 5.3 kg/m(2)). Six months post RYGB, mean BMI decreased to 35.4 ± 4.5, corresponding to 51.7% excess weight loss (P < 0.001). Mean waist circumference decreased significantly from 132 cm at baseline to 110 cm at 3 months (P = 0.003) and 107 cm at 6 months (P < 0.001). Six months after RYGB, weight loss led to significant improvements in clinical parameters indicative of cardiovascular disease or risk, including brachial artery diameter, endothelial independent vasodilation, and FRS. Favorable improvements in the proinflammatory markers CRP (P = 0.01) and leptin (P = 0.005), the anti-inflammatory mediator adiponectin (P = 0.002), and insulin sensitivity (HOMA-IR, P = 0.007) were evident at 3 months. At 6 months, improvements in CRP, leptin, and fasting insulin were maintained and fibrinogen levels also decreased (P = 0.047). Adiponectin continued to increase at 6 months (P = 0.004).

CONCLUSION

Gastric bypass is associated with early reversal of endothelial dysfunction, a more favorable inflammatory milieu, and, most importantly, a reduction in cardiovascular risk.

Metabolic surgery and cancer: protective effects of bariatric procedures

The worldwide epidemic of obesity and the global incidence of cancer are both increasing. There is now epidemiological evidence to support a correlation between obesity, weight gain, and some cancers. Metabolic or bariatric surgery can provide sustained weight loss and reduced obesity-related mortality. These procedures can also improve the metabolic profile to decrease cardiovascular risk and resolve diabetes in morbidly obese patients. The operations offer several physiological steps, the so-called BRAVE effects: 1) bile flow alteration, 2) reduction of gastric size, 3) anatomical gut rearrangement and altered flow of nutrients, 4) vagal manipulation and 5) enteric gut hormone modulation. Metabolic operations are also associated with a significant reduction of cancer incidence and mortality. The cancer-protective role of metabolic surgery is strongest for female obesity-related tumors; however, the underlying mechanisms may involve both weight-dependent and weight-independent effects. These include the improvement of insulin resistance with attenuation of the metabolic syndrome as well as decreased oxidative stress and inflammation in addition to the beneficial modulation of sex steroids, gut hormones, cellular energetics, immune system, and adipokines. Elucidating the precise metabolic mechanisms of cancer prevention by metabolic surgery can increase our understanding of how obesity, diabetes, and metabolic syndrome are associated with cancer. It may also offer novel treatment strategies in the management of tumor generation and growth.

Thrombin generation in morbid obesity: significant reduction after weight loss

BACKGROUND

Patients with morbid obesity (MO; body mass index > 40 kg m(-2)) suffer from an increased risk of cardiovascular disease, stroke, venous thromboembolism and all-cause mortality.

OBJECTIVES

Because weight loss by bariatric surgery reduces cardiovascular and all-cause mortality, we hypothesized that the plasmatic clotting system might be involved in cardiovascular risk.

PATIENTS/METHODS

Thirty-six MO patients [mean age 42 (+/-13) years; 29 female) were investigated before and 2 years after bariatric surgery. Thrombin generation was measured with a commercially available assay (Technothrombin-TGA,Technoclone). Metabolic parameters and parameters of the hemostatic system, such as tissue factor (TF), TF pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1) and prothrombinfragment 1.2 (F1.2), were determined. To investigate associations of changing parameters, deltas were calculated.

RESULTS

Metabolic parameters improved with a mean weight loss of 41 (+/-19) kg. Postoperatively, the lag phase was significantly extended compared with preoperative values [median (25th-75th percentile), 7 (4-12) vs. 12 (7-19) min, P = 0.005]. Peak thrombin decreased after weight loss from 345 (232-455) to 282 (111-388) nm (P = 0.015) and the area under the curve from 3962 (3432-5023) to 3227 (2202-4030) nm thrombin (P < 0.001). TF, PAI-1 and F1.2 significantly decreased after weight loss. Analyses of the deltas showed a significant correlation between peak thrombin and total cholesterol (r = 0.50), triglycerides (r = 0.46) and HbA1c (r = 0.55). Moreover, an inverse correlation was found between insulin resistance and the lag phase (r = -0.46).

CONCLUSION

Thrombin generation, a marker of the overall coagulation potential, decreased significantly with weight reduction. This might, at least in part, explain the decreased risk of cardiovascular disease after bariatric surgery.

[Soluble intercellular adhesion molecule-1 and C reactive protein after bariatric surgery]

BACKGROUND AND OBJECTIVES

Obesity is associated with a state of chronic low-grade inflammation. A causal association between inflammatory processes and atherogenesis has been proposed. The aim of this study was to evaluate changes in the proinflammatory profile of morbidly obese patients who underwent bariatric surgery. Serum C-reactive protein (CRP) and soluble intercellular adhesion molecule-1 (sICAM-1) concentrations were measured before and after massive weight loss due to gastric bypass.

METHODS

In this prospective study we measured CRP and sICAM-1 concentrations in 50 morbidly obese patients (19 men and 31 women) at baseline and 3, 6 and 12 months after gastric bypass.

RESULTS

Body mass index (BMI), CRP, and sICAM-1 decreased significantly. BMI correlated with CRP but not with sICAM-1.

CONCLUSIONS

The improvement in vascular risk profile after weight loss in morbidly obese patients could be partially explained by changes in inflammatory status.

Effects of lifestyle measures, antiobesity agents, and bariatric surgery on serological markers of inflammation in obese patients

Overweight and obesity are highly prevalent in developed countries and are also becoming more frequent in the developing world. Overweight and obese patients have elevated levels of several inflammatory markers and this inflammatory state might contribute to their increased vascular risk. We summarize the effects of lifestyle changes, antiobesity agents, and bariatric surgery on serological inflammatory markers in overweight and obese patients. Most studies showed a decrease in inflammation with all 3 interventions. However, it remains to be established whether the decrease in inflammatory markers induced by lifestyle changes or (where indicated) with antiobesity agents or bariatric surgery will translate into reduced vascular morbidity and mortality in overweight and obese patients.