Effects of Roux-en-Y gastric bypass or diabetes support and education on insulin sensitivity and insulin secretion in morbidly obese patients with type 2 diabetes

Effects of Roux-en-Y Gastric Bypass and Sleeve Gastrectomy on β-Cell Function at 1 Year After Surgery: A Systematic Review

Bariatric surgery is a highly effective obesity treatment resulting in substantial weight loss and improved glucose metabolism. We hereby aimed to summarize available evidence of the effect of the 2 most common bariatric surgery procedures, Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), on dynamic measures of β-cell function (BCF). A systematic search of the literature was conducted in 3 bibliographic databases for studies reporting effects of RYGB and/or SG on BCF assessed using dynamic metabolic perturbation (oral or intravenous bolus stimulation), performed before and 1 year (±3 months) after surgery. Twenty-seven unique studies (6 randomized controlled trials and 21 observational studies), involving a total of 1856 obese adults, were included for final analysis. Twenty-five and 9 studies report effects of RYGB and SG on BCF, respectively (7 studies compared the 2 procedures). Seven studies report results according to presurgical diabetes status. Owing to variable testing procedures and BCF indices reported, no meta-analysis was feasible, and data were summarized qualitatively. For both surgical procedures, most studies suggest an increase in BCF and disposition index, particularly when using oral stimulation, with a more pronounced increase in diabetic than nondiabetic individuals. Additionally, limited indications for greater effects after RYGB versus SG were found. The quality of the included studies was, in general, satisfactory. The considerable heterogeneity of test protocols and outcome measures underscore the need for a harmonization of BCF testing in future research.

Renal insulin resistance in type 2 diabetes mellitus and progression of chronic kidney disease: potential pathogenic mechanisms

INTRODUCTION

A bidirectional association exists between insulin resistance (IR) and chronic kidney disease (CKD) in Type 2 Diabetes Mellitus (T2DM). Baseline measures of IR are predictive of CKD progression, and uremia in progressive CKD is itself, in turn, associated with a worsening of IR. Pre-clinical research reveals that intrinsic IR in glomerular podocytes and the renal tubule may serve as a pathogenic driver of CKD in T2DM.

AREAS COVERED

The present manuscript takes as its point of departure, the recently identified prognostic utility of severe insulin resistance as a predictor of CKD in T2DM. Findings from a series of studies describing the association of IR with pathological alterations in both established, and less commonly assessed dynamic measures of renal impairment are discussed. Drawing upon the pre-clinical mechanistic evidence base, the cellular and molecular basis of intrinsic renal IR as a promoter of CKD is considered.

EXPERT OPINION

Measurement of insulin sensitivity may add value to profiling of renal risk in T2DM. Rational selection of therapeutic strategies targeting the enhancement of insulin sensitivity merits special attention regarding the personalized management of CKD in insulin resistance predominant T2DM.

Changes of Circulating Irisin and High-Sensitivity C-Reactive Protein Levels in Morbidly Obese Individuals with Type 2 Diabetes After Roux-en-Y Gastric Bypass

Background: Irisin has been recently reported to provide beneficial effects in obesity and diabetes. Elevation of high-sensitivity C-reactive protein (hs-CRP) reflects the inflammatory state that has been shown to play a key role in obesity and its comorbidities. Objective: Our study aimed to compare the changes of circulating irisin levels in an obese diabetic population who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB) versus a control-matched population who underwent usual medical care plus diabetes support education (DSE) program. In addition, we aimed to explore the association between circulating irisin and hs-CRP levels after the interventions. Methods: In a prospective controlled trial, we studied 58 obese individuals with type 2 diabetes before and 12 months after intervention. Twenty-nine subjects underwent LRYGB and 29 subjects received DSE. Results: At 12-month follow-up, compared with the DSE group, patients who underwent LRYGB lost more weight (LRYGB; -33.4 ± 11.2, and DSE; 0.2 ± 4.9 kg; P < .001), fat mass (P < .001), and fat-free mass (P < .05). Circulating irisin (P < .05) and hs-CRP level (P < .05) were also significantly lower. Within the LRYGB group, the reduction of irisin level was positively associated with the changes of hs-CRP levels (r = 0.39, P < .05). Conclusions: To the best of our knowledge, this is the first study showing that LRYGB significantly reduces circulating irisin levels compared with usual medical care and DSE, in an obese diabetic population. After LRYGB, the irisin reduction significantly correlates with the reduction of hs-CRP. The elevation of circulating irisin levels suggests irisin resistance in the obese state and its decrease after LRYGB might reflect the resolution of irisin resistance. Future investigations are needed to confirm and explore the mechanisms of irisin resistance in obesity, its resolution after LRYGB, and the pathophysiological significance.

The magnitude and progress of lean body mass, fat-free mass, and skeletal muscle mass loss following bariatric surgery: A systematic review and meta-analysis

Postbariatric loss of muscle tissue could negatively affect long-term health due to its role in various bodily processes, such as metabolism and functional capacity. This meta-analysis aimed to unravel time-dependent changes in the magnitude and progress of lean body mass (LBM), fat-free mass (FFM), and skeletal muscle mass (SMM) loss following bariatric surgery. A systematic literature search was conducted in Pubmed, Embase, and Web of Science. Fifty-nine studies assessed LBM (n = 37), FFM (n = 20), or SMM (n = 3) preoperatively and ≥1 time points postsurgery. Random-effects meta-analyses were performed to determine pooled loss per outcome parameter and follow-up time point. At 12-month postsurgery, pooled LBM loss was -8.13 kg [95%CI -9.01; -7.26]. FFM loss and SMM loss were -8.23 kg [95%CI -10.74; -5.73] and -3.18 kg [95%CI -5.64; -0.71], respectively. About 55% of 12-month LBM loss occurred within 3-month postsurgery, followed by a more gradual decrease up to 12 months. Similar patterns were seen for FFM and SMM. In conclusion, >8 kg of LBM and FFM loss was observed within 1-year postsurgery. LBM, FFM, and SMM were predominantly lost within 3-month postsurgery, highlighting that interventions to mitigate such losses should be implemented perioperatively.

How Does Fat Mass Change in the First Year After Bariatric Surgery? A Systemic Review and Meta-Analysis

This systematic review and meta-analysis investigated the time-course effect of different type of bariatric surgeries (BS) up to 1 year post-surgery on fat mass (FM) and body fat percentage (BFP) in patients with morbid obesity. We searched PubMed, Scopus, EMBASE, ISI web of science, and Cochrane databases from October 2002 until May 2020 with no restriction in the English language, to find studies examining the effect of BS on FM (kg) and BFP (%) in morbid obese patients. Meta-analysis of 103 studies carried out on data of 18,166 and 14,575 morbid obese patients following BS, showed that BS was associated with a substantial decrease in FM and BFP, respectively, in 1 month (- 8.17 kg [95% CI - 9.07, - 7.27] and - 1.51% [95% CI - 2.56, - 0.46]), 3 months (- 15.75 [95% CI - 17.49, - 14.0] and - 4.90 [95% CI - 5.97, - 3.83]), 6 months (- 22.51 [95% CI - 23.93, - 21.09] and - 8.56% [95% CI - 9.63, - 7.49]), and 12 months (- 29.69 [95% CI - 31.3, - 28.09] and - 13.49% [95% CI - 14.52, - 12.40]) after the surgery. In conclusion, BS was associated with sustained declines in FM and BFP, from 1 to 12 months, with no indication of plateau phase post-surgery post-operatively. The present study emphasizes that post-bariatric care should have more focus on FM loss during 1-year post-surgery to identify the patients at risk for fat loss plateau.

Roux-en-Y gastric bypass decreases serum inflammatory markers and cardiovascular risk factors in obese diabetics

BACKGROUND

Obesity and type 2 diabetes mellitus are associated with elevated levels of inflammatory markers. This chronic inflammation is known to contribute to increased risk of cardiovascular disease in these populations. Laparoscopic Roux-en-Y gastric bypass is associated with a high rate of diabetes remission. We hypothesize that laparoscopic Roux-en-Y gastric bypass decreases systemic inflammatory markers and cardiovascular disease risk factors in obese diabetics.

METHODS

This was a single-institution prospective cohort study of 61 obese patients with type 2 diabetes mellitus. A total of 30 patients underwent laparoscopic Roux-en-Y gastric bypass surgery, and 31 patients underwent standard medical therapy with diabetes support and education. Collected data included preoperative and postoperative inflammatory biomarkers and clinical parameters.

RESULTS

Twelve months after undergoing laparoscopic Roux-en-Y gastric bypass, controlling for sex and age, there was a significant correlation between a change in interleukin-6 and a change in systolic blood pressure (Spearman r = 0.41, P = .03). Similarly, when sex and age were controlled for in the laparoscopic Roux-en-Y gastric bypass group, a statistically significant relationship remained between percent excess weight loss and change in interleukin-6 (P = .001).

CONCLUSION

A significant relationship exists between decreased systemic interleukin-6 levels and both excess weight loss and lowered systolic blood pressure after laparoscopic Roux-en-Y gastric bypass in obese patients with diabetes mellitus. These correlations may explain the decreased risk of cardiovascular disease after surgical weight reduction in this patient population.

Ongoing Inconsistencies in Weight Loss Reporting Following Bariatric Surgery: a Systematic Review

Weight loss is the primary outcome following bariatric surgery; however, its documentation within current literature is heterogeneous and poorly defined, limiting meaningful comparison between studies. Randomized controlled trials from 2012 to 2016 were identified using the Medline database through "Gastric bypass OR sleeve gastrectomy AND weight" search terms. A total of 73 studies with 5948 patients were included. Reporting of preoperative weight was done primarily using mean body mass index (BMI) (87.7%) and mean weight (65.8%). Postoperative weight reporting was more variable, with the most frequently reported measure being mean postoperative BMI (71.2%). Overall, nearly one third of all bariatric literature contained discrepancies that precluded meaningful meta-analysis. Reporting of weight loss following bariatric surgery is becoming increasingly diverse for both pre- and post-operative outcomes. Ongoing heterogeneity will continue to act as a barrier to meaningful comparison of bariatric outcomes until standardized reporting practices become adopted.

Effects of Roux-en-Y Gastric Bypass on Osteoclast Activity and Bone Density in Morbidly Obese Patients with Type 2 Diabetes

INTRODUCTION

Roux-en-Y gastric bypass (RYGB) is a well-established treatment for morbid obesity and type 2 diabetes. The effects of RYGB on bone metabolism and bone health are largely unknown.

OBJECTIVE

Determine the changes in osteoclast function and bone density 1 year after RYGB as compared with a control group undergoing a diabetes support and education program (DSE).

DESIGN

A prospective cohort study with patients matched for weight and age assigned to RYGB or DSE.

SETTING

Large academic institution.

PATIENTS OR OTHER PARTICIPANTS

Patients with type 2 diabetes mellitus and morbid obesity (body mass index greater than 35 kg/m2).

INTERVENTION

Subjects either received laparoscopic RYBG or DSE, which consisted of nutritional, exercise, and dietary counseling performed by a certified diabetic educator and a nutritionist three times over a year.

MAIN OUTCOME MEASURE

Osteoclast activity, bone mineral density.

RESULTS

One year after, intervention subjects undergoing RYGB have a 280% increase in osteoclast activity as compared with a 7.6% increase in the DSE control group (P < 0.001). Furthermore, there was a statistically significant increase in sclerostin levels in subjects undergoing RYGB compared with an increase in the control group. The total bone mineral density was statistically unchanged within 1 year of intervention in both groups. A statistically significant decrease in bone mineral density in the left ribs (decrease of 6.8%, P < 0.05) and lumbar spine (decrease of 4.0%, P < 0.05) was seen 1 year after RYGB.

CONCLUSIONS

There is a significant increase in osteoclast activity observed 1 year after RYGB; the long-term clinical implications of this increased bone metabolism are unknown.

The Effects of Bariatric Surgery on Type 2 Diabetes in Asian Populations: a Meta-analysis of Randomized Controlled Trials

BACKGROUND

To evaluate the effects of bariatric surgery on patients with type 2 diabetes through comparing Asian and non-Asian populations according to follow-up time.

METHODS

In this meta-analysis of randomized controlled trials (RCTs), we searched PubMed databases for relevant articles. A meta-analysis was undertaken of 37 eligible RCTs.

RESULTS

Diabetes remission rates among Asian populations were similar to those of non-Asian populations at 1 year (95% confidence interval (CI) 0.519 [0.417, 0.619] vs 0.571 [0.316, 0.794], respectively) but were found to be higher in Asian populations at 2 years compared to non-Asian populations (95% CI 0.672 [0.469, 0.826] vs 0.563 [0.220, 0.855], respectively). Asian populations showed greater reductions in HbA1c (- 3.512 [- 2.726, - 4.299], - 3.001 [- 1.433, - 4.569], and - 3.345 [- 2.267, - 4.423]) than non-Asian populations (- 2.129 [- 1.821, - 2.438], - 2.301 [- 1.881, - 2.722], and - 2.107 [- 1.941, - 2.273]) at 1, 2, and 5 years, respectively. Asian populations also showed greater reductions of fasting plasma glucose than non-Asian populations, and these effects were prominent at 3- and 5-year follow-up (Asian populations, - 83.297 [- 73.264, - 93.331]; non-Asian populations, - 54.288 [- 37.409, - 71.166] at 3 years; Asian populations, - 99.014 [- 82.239, - 115.788]; non-Asian populations, - 45.756 [- 21.892, - 69.621] at 5 years).

CONCLUSIONS

Bariatric surgery is more successful in diabetes remission and glucose outcome improvement in Asian populations with type 2 diabetes than in non-Asian populations, even over long-term follow-up periods. Bariatric surgery can be considered an effective treatment option and may present an appropriate opportunity to improve the prognosis for Asian patients with type 2 diabetes.

The Effects of Bariatric Surgery on Islet Function, Insulin Secretion, and Glucose Control

Although bariatric surgery was developed primarily to treat morbid obesity, evidence from the earliest clinical observations to the most recent clinical trials consistently demonstrates that these procedures have substantial effects on glucose metabolism. A large base of research indicates that bariatric surgeries such as Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), and biliopancreatic diversion (BPD) improve diabetes in most patients, with effects frequently evident prior to substantial weight reduction. There is now unequivocal evidence from randomized controlled trials that the efficacy of surgery is superior to intensive life-style/medical management. Despite advances in the clinical understanding and application of bariatric surgery, there remains only limited knowledge of the mechanisms by which these procedures confer such large changes to metabolic physiology. The improvement of insulin sensitivity that occurs with weight loss (e.g., the result of diet, illness, physical training) also accompanies bariatric surgery. However, there is evidence to support specific effects of surgery on insulin clearance, hepatic glucose production, and islet function. Understanding the mechanisms by which surgery affects these parameters of glucose regulation has the potential to identify new targets for therapeutic discovery. Studies to distinguish among bariatric surgeries on key parameters of glucose metabolism are limited but would be of considerable value to assist clinicians in selecting specific procedures and investigators in delineating the resulting physiology. This review is based on literature related to factors governing glucose metabolism and insulin secretion after the commonly used RYGB and VSG, and the less frequently used BPD and adjustable gastric banding.

Improvement in insulin resistance after gastric bypass surgery is correlated with a decline in plasma 2-hydroxybutyric acid

BACKGROUND

Gastric bypass surgery for weight reduction often corrects dysglycemia in diabetic patients, but a full understanding of the underlying biochemical pathways continues to be investigated.

OBJECTIVES

To explore the effects of weight loss by surgical and dietary interventions on plasma metabolites using both targeted and discovery-oriented metabolomics platforms.

SETTING

An academic medical center in the United States.

METHODS

Improvement in homeostatic model assessment for insulin resistance (HOMA-IR), as an index of insulin resistance, was compared at 6 months in 11 patients that underwent Roux-en-Y gastric bypass against 11 patients that were matched for weight loss in the Weight Loss Maintenance (WLM) program. Metabolites in plasma were evaluated by nontargeted gas chromatography/mass spectrometry for the potential detection of >1100 biochemical markers.

RESULTS

Among multiple metabolites detected, 2-hydroxybutyric acid (2-HBA) declined most significantly after 6 months in comparing patients that underwent Roux-en-Y gastric bypass with those in WLM (P < .001), corresponding with declines in HOMA-IR (P = .025). Baseline levels of 2-HBA for all patients were correlated with preintervention levels of HOMA-IR (R² = .565, P < .001). Moreover, the changes in 2-HBA after 6 months were correlated with changes in HOMA-IR (R² = .399, P = .0016).

CONCLUSIONS

Correlation between insulin resistance and 2-HBA suggests the utility of the latter as an excellent biomarker for tracking glycemic improvement, and offers further insight into the pathways that control diabetes. This is the first report of a decline in 2-HBA in response to bariatric surgery.

Gastric bypass significantly improves quality of life in morbidly obese patients with type 2 diabetes

OBJECTIVE

To evaluate the impact of Roux-en-Y gastric bypass (RYGB) on quality of life in obese diabetic patients compared to standard medical therapy for type 2 diabetes mellitus.

METHODS

We prospectively studied two matched obese populations with type 2 diabetes. Thirty patients underwent laparoscopic RYGB and 31 received standard medical therapy combined with a diabetes support and education program (DSE), consisting of educational sessions on diet and exercise. Groups were matched by age, gender, weight, glucostatic parameters, and use of glucose-lowering medications (oral agents and insulin therapy). Health-related quality of life (HRQOL) was assessed using the normalized SF-36 questionnaire, and data were collected at baseline and at 12-month follow-up.

RESULTS

Diabetic patients who underwent RYGB experienced a statistically significant increase in their overall HRQOL. However, the role-physical and mental health domains increased but did not reach statistical significance. Diabetic patients in the medical therapy and DSE group did not show any significant increase in HRQOL. The between-group differences for the HRQOL changes from baseline were significant, other than for role-physical and mental health domains. Percentage changes in glucostatic parameters, discontinuation of glucose-lowering medications, and T2DM remission were not found to predict the percentage change in SF-36 scores at 12 months after RYGB.

CONCLUSIONS

For the first time, with a prospective matched control study, we demonstrate a significant improvement in HRQOL in obese diabetic patients who underwent RYGB, but not in those who were offered standard medical therapy and DSE.

Novel therapeutics for type 2 diabetes: insulin resistance

Insulin resistance (IR) plays an important role in the pathogenesis of type 2 diabetes (T2D) and cardiovascular disease. Hence improving IR is a major target of treatment in patients with T2D. Obesity and lack of exercise are major causes of IR. However, recent evidence implicates sleep disorders and disorders of the circadian rhythm in the pathogenesis of IR. Weight loss and lifestyle changes are the cornerstone and most effective treatments of IR, but adherence and patient's acceptability are poor. Bariatric surgery results in significant and sustainable long-term weight loss associated with beneficial impact on IR and glucose metabolism, making this an attractive treatment option for patients with T2D. Currently available pharmacological options targeting IR (such as metformin and thiazolidinediones) do not maintain glycaemic measures within targets long term and can be associated with significant side effects. Over the last two decades, many pharmacological agents targeting different aspects of the insulin signalling pathway were developed to improve IR, but only a minority reached clinical trials. Such treatments need to be specific and reversible as many of the components of the insulin signalling pathway are involved in other cellular functions such as apoptosis. Recent evidence highlighted the role of circadian rhythm and sleep-related disorders in the pathogenesis of IR. In this article, we review the latest developments in the pharmacological and non-pharmacological interventions targeting IR including bariatric surgery. We will also review the role of circadian rhythm and sleep-related disorders in the development and treatment of IR.

Improved insulin sensitivity after gastric bypass correlates with decreased total body fat, but not with changes in free fatty acids

BACKGROUND

Increased plasma free fatty acids (FFAs) are considered one of the key elements in the pathogenesis of insulin resistance (IR) and type 2 diabetes (T2DM). We hypothesize that, in diabetic patients undergoing laparoscopic Roux-en-Y gastric bypass (LRYGB), a postoperative decrease in FFA will correlate with improved insulin sensitivity (Si).

METHODS

A total of 30 obese [body mass index ((BMI) >35 kg/m(2)] patients with a diagnosis of T2DM were studied preoperatively and 12 months after LRYGB in a prospective cohort study. Collected data included intravenous glucose tolerance test (IVGTT), total body composition by dual-energy X-ray absorptiometry and plasma levels of FFA. Si analysis from the IVGTT was estimated from minimal model analysis. Pre- and postoperative variables were compared using a paired sample t test. Relationships between changes in variables were determined with Pearson's correlation test.

RESULTS

Twelve months after LRYGB the study population showed a significant decrease in BMI (p = 0.001), FFA (p = 0.03), and total body fat (p = 0.03), with an increase in Si (p = 0.001). Postoperative changes in Si significantly correlated (Pearson's r = -0.53, p = 0.01) with change in total body fat, but not with changes in plasma FFA (Pearson's r = -0.22, p = 0.31).

CONCLUSIONS

Our study challenges the notion that IR is mediated to a significant degree by changes in plasma FFA concentration. Instead, changes in adiposity and consequently changes in adipokine release can be the key players in determining remission of T2DM after LRYGB.