Improvements in the metabolic milieu following Roux-en-Y gastric bypass and the arrest of diabetic kidney disease

From diabetes to diverse domains: the multifaceted roles of GLP-1 receptor agonists

Glucagon-like Peptide-1 (GLP-1) receptor agonists (GLP-1RAs) emerged as a primary treatment for type-2 diabetes mellitus (T2DM), however, their multifaceted effects on various target organs beyond glycemic control opened a new era of treatment. We conducted a comprehensive literature search using databases including Scopus, Google Scholar, PubMed, and the Cochrane Library to identify clinical, in-vivo, and in-vitro studies focusing on the diverse effects of GLP-1 receptor agonists. Eligible studies were selected based on their relevance to the varied roles of GLP-1RAs in T2DM management and their impact on other physiological functions. Numerous studies have reported the efficacy of GLP-1RAs in improving outcomes in T2DM, with demonstrated benefits including glucose-dependent insulinotropic actions, modulation of insulin signaling pathways, and reductions in glycemic excursions. Additionally, GLP-1 receptors are expressed in various tissues and organs, suggesting their widespread physiological functions beyond glycemic control potentially include neuroprotective, anti-inflammatory, cardioprotective, and metabolic benefits. However, further scientific studies are still underway to maximize the benefits of GLP-1RAs and to discover additional roles in improving health benefits. This article sought to review not only the actions of GLP1RAs in the treatment of T2DM but also explore its effects on potential targets in other disorders.

Renal Function Following Bariatric Surgery: a Literature Review of Potential Mechanisms

Obesity is a major and independent risk factor for onset and progression of many renal diseases. Bariatric surgery (BS) improves renal function by improving obesity-related metabolic disorders. However, the procedure is also accompanied by renal risks, including acute kidney injury (AKI) and oxalate nephropathy. Here, we briefly review the history and principle of frequently applied technique for BS and summarize the comprehensive BS effect on kidney function. Importantly, we highlight the possible molecular mechanisms associated with the recovery of renal function to provide novel ideas for future studies and clinical applications.

Association between weight loss and reduced use of antihypertensive, hypoglycemic, psychotropic, and lipid-lowering drugs in patients undergoing bariatric surgery

Objectives: To analyze whether the weight reduction observed in bariatric surgery (Roux-en-Y gastric bypass; BGYR) is accompanied by a reduction in the use of antihypertensive, hypoglycemic, antilipidemic, and psychotropic drugs after 6 and 12 months. Methods: Longitudinal, retrospective study of 100 adult patients undergoing RYGB from May 2015 to January 2019, by laparotomy or laparoscopy. Data on age, body mass index (BMI), and the number of drugs used were recorded 6 and 12 months after surgery. Results: The mean age was 39.7 ± 9.7 years, and the majority were female (n = 78). The mean preoperative BMI was 43.7 ± 5.1 kg/m2, and the mean reduction in BMI after 6 months was 12.1 kg/m2 and 14.9 kg/m2 after 12 months. The reduction in antihypertensive drugs was 65.2% after 6 months and 96% after 12 months. The reduction in 6 months of hypoglycemic agents was 84.3%, and in 12 months, 98.3%. The average reduction in antidyslipidemic drugs was 86.7% in 6 months, and there was no record of using this medication after 12 months. Psychotropics showed a temporary reduction in use after 6 months with a return to levels close to the baseline after 1 year.There was no correlation between the variation in BMI and the use of drugs. Conclusions: there was a significant reduction in the use of drugs after 6 and 12 m, except for psychotropic drugs. The reduction in the use of drugs was not correlated with a reduction in BMI.

The Construction and Analysis of the Aberrant lncRNA-miRNA-mRNA Network in Adipose Tissue from Type 2 Diabetes Individuals with Obesity

BACKGROUND

The prevalence of obesity and type 2 diabetes mellitus (T2DM) has become the most serious global public health issue. In recent years, there has been increasing attention to the role of long noncoding RNAs (lncRNAs) in the occurrence and development of obesity and T2DM. The aim of this work was to find new lncRNAs as potential predictive biomarkers or therapeutic targets for obesity and T2DM.

METHODS

In this study, we identified significant differentially expressed mRNAs (DEmRNAs) and differentially expressed lncRNAs (DElncRNAs) between adipose tissue of individuals with obesity and T2DM and normal adipose tissue (absolute log₂FC ≥ 1 and FDR < 0.05). Then, the lncRNA-miRNA interactions predicted by miRcode were further screened with a threshold of MIC > 0.2. Simultaneously, the mRNA-miRNA interactions were explored by miRWalk 2.0. Finally, a ceRNA network consisting of lncRNAs, miRNAs, and mRNAs was established by integrating lncRNA-miRNA interactions and mRNA-miRNA interactions.

RESULTS

Upon comparing adipose tissue from individuals with obesity and T2DM and normal adipose tissues, 364 significant DEmRNAs, including 140 upregulated and 224 downregulated mRNAs, were identified in GSE104674; in addition, 231 significant DEmRNAs, including 146 upregulated and 85 downregulated mRNAs, were identified in GSE133099. GO and KEGG analyses have shown that downregulated DEmRNAs in GSE104674 and GSE133099 were associated with obesity- and T2DM-related biological pathways, such as lipid metabolism, AMPK signaling, and insulin resistance. Furthermore, 28 significant DElncRNAs, including 14 upregulated and 14 downregulated lncRNAs, were found. Based on the predicted lncRNA-miRNA and mRNA-miRNA relationships, we constructed a competitive endogenous RNA (ceRNA) network, including five lncRNAs, ten miRNAs, and 15 mRNAs. KEGG-GSEA analysis revealed that four lncRNAs (FLG-AS1, SNAI3-AS1, AC008147.0, and LINC02015) in the ceRNA network were related to the biological pathways of metabolic diseases.

CONCLUSIONS

Through ceRNA network analysis, our study identified four new lncRNAs that may be used as potential biomarkers and therapeutic targets of obesity and T2DM, thus laying a foundation for future clinical studies.

Microarray Profiling and Coexpression Network Analysis of Long Noncoding RNAs in Adipose Tissue of Obesity-T2DM Mouse

OBJECTIVE

The aim of this study was to understand more about long noncoding RNAs (lncRNAs) as potential prediction biomarkers or therapeutic targets for obesity and type 2 diabetes mellitus (T2DM). This study aimed to find more lncRNA candidates related to obesity and T2DM.

METHODS

In this study, a high-fat diet (HFD)-induced obesity-T2DM mouse model was used, and a mRNA and lncRNA expression map was drawn up in adipose tissue by microarray technology. Then Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis were performed and revealed that the most associated genes and pathways were metabolism-related ones. The candidate lncRNA expression was further validated in adipose tissue from HFD-induced mice by quantitative real-time polymerase chain reaction analysis.

RESULTS

Transcriptome analyses were performed to show expression profiles of mRNAs and lncRNAs in epididymal adipose tissue in the obesity-T2DM mice. A total of 124 lncRNAs and 1,606 mRNAs were differentially expressed between the chow and HFD groups. Then, an mRNA-lncRNA coexpression network was constructed. Based on a series of analyses, 15 candidate lncRNAs were screened, and their expression was further validated by quantitative real-time polymerase chain reaction analysis.

CONCLUSIONS

The results reveal significant differences between the transcriptomes of the HFD and control groups in adipose tissue that provide clues to the molecular mechanisms of diet-induced metabolic disorders as well as biomarkers of risk for these disorders.

Specialized Pro-resolving Lipid Mediators: Modulation of Diabetes-Associated Cardio-, Reno-, and Retino-Vascular Complications

Diabetes and its associated chronic complications present a healthcare challenge on a global scale. Despite improvements in the management of chronic complications of the micro-/macro-vasculature, their growing prevalence and incidence highlights the scale of the problem. It is currently estimated that diabetes affects 425 million people globally and it is anticipated that this figure will rise by 2025 to 700 million people. The vascular complications of diabetes including diabetes-associated atherosclerosis and kidney disease present a particular challenge. Diabetes is the leading cause of end stage renal disease, reflecting fibrosis leading to organ failure. Moreover, diabetes associated states of inflammation, neo-vascularization, apoptosis and hypercoagulability contribute to also exacerbate atherosclerosis, from the metabolic syndrome to advanced disease, plaque rupture and coronary thrombosis. Current therapeutic interventions focus on regulating blood glucose, glomerular and peripheral hypertension and can at best slow the progression of diabetes complications. Recently advanced knowledge of the pathogenesis underlying diabetes and associated complications revealed common mechanisms, including the inflammatory response, insulin resistance and hyperglycemia. The major role that inflammation plays in many chronic diseases has led to the development of new strategies aiming to promote the restoration of homeostasis through the "resolution of inflammation." These strategies aim to mimic the spontaneous activities of the 'specialized pro-resolving mediators' (SPMs), including endogenous molecules and their synthetic mimetics. This review aims to discuss the effect of SPMs [with particular attention to lipoxins (LXs) and resolvins (Rvs)] on inflammatory responses in a series of experimental models, as well as evidence from human studies, in the context of cardio- and reno-vascular diabetic complications, with a brief mention to diabetic retinopathy (DR). These data collectively support the hypothesis that endogenously generated SPMs or synthetic mimetics of their activities may represent lead molecules in a new discipline, namely the 'resolution pharmacology,' offering hope for new therapeutic strategies to prevent and treat, specifically, diabetes-associated atherosclerosis, nephropathy and retinopathy.

Renal experiences of bariatric surgery in patients with type 2 diabetes mellitus

The review addresses the questions of the literature devoted to the problem of the influence of bariatric surgery on the course of diabetic nephropathy in patients with diabetes mellitus type 2 after achieving a surgically induced remission. This approach was shown to have positive aspects, such as decrease in creatinine, decrease in albuminuria, an increase in GFR, normalization of glycemia and blood pressure, "incretin effect"’s influence on the kidneys. Descriptions of the currently expected pathogenetic mechanisms involved in achieving the observed improvement in microvascular complications of diabetes, namely diabetic kidney disease, are also described in details.

Impact of bariatric surgery on cardiovascular and renal complications of diabetes: a focus on clinical outcomes and putative mechanisms

INTRODUCTION

Cardiovascular and renal disease accounts for a substantial proportion of the morbidity and mortality associated with obesity and type 2 diabetes mellitus (T2DM). Bariatric surgery is associated with improved long-term cardiovascular and renal outcomes.

AREAS COVERED

All major case-control, cohort, and randomized controlled trial studies of bariatric surgery in adults with T2DM were screened and data on prespecified cardiovascular and renal outcomes collated. Bariatric surgery reduces all-cause mortality and risk of cardiovascular disease, albuminuria and progressive chronic kidney disease. Patients with poorer glycemic control and established microvascular disease preoperatively may stand to benefit the most from the surgical approach. Reduced sympathetic drive, remission of glomerular hypertension, enhanced natriuresis, gut microbiota shifts, reduced systemic and renal inflammation, improved lipoprotein profiles, and reductions in chronic cardiac remodeling may all be implicated.

EXPERT COMMENTARY

Ongoing RCTs of bariatric surgery selectively recruiting patients with class 1 obesity and established microvascular complications of diabetes will help to better characterize which subgroups of patients benefit most from this effective therapy.

Effect of bariatric surgery on diabetic nephropathy in obese type 2 diabetes patients in a retrospective 2-year study: A local pilot

PURPOSE

To determine the effects of bariatric surgery on albuminuria in obese patients with type 2 diabetes mellitus.

METHODS

Retrospective analyses of clinical records of obese patients with type 2 diabetes mellitus who had either micro- or macroalbuminuria and had undergone various bariatric surgery were retrieved from a local hospital database. Their clinical data from follow-up appointments including albuminuria were analysed.

RESULTS

Of the 46 subjects with type 2 diabetes mellitus, 15 subjects had diabetic nephropathy and had pre- and post-bariatric surgery urine albumin-to-creatinine ratio or urine protein-to-creatinine ratio data available for analysis; 13 out of the 15 subjects (86.7%) showed improvement of urine albumin-to-creatinine ratio or urine protein-to-creatinine ratio after surgery; 2 showed equivocal results; 9 of 13 subjects (69.2%) showed remission of diabetic nephropathy; 7 of these 9 patients had microalbuminuria before surgery, 2 had macroalbuminuria before surgery. There were significant improvements to glycosylated haemoglobin, fasting plasma glucose, blood pressure and body weight post surgery. The usage of insulin and oral medications dropped significantly post surgery for all subjects.

CONCLUSION

This study shows that bariatric surgery significantly improves diabetic nephropathy in obese type 2 diabetes mellitus subjects. The results suggest that in our local type 2 diabetes mellitus patients, it is possible not only to improve metabolic parameters, but also to reverse what may be considered established microvascular complications by means of bariatric surgery.

Glucagon-like peptide-1 analog prevents obesity-related glomerulopathy by inhibiting excessive autophagy in podocytes

To investigate the role of glucagon-like peptide-1 analog (GLP-1) in high-fat diet-induced obesity-related glomerulopathy (ORG). Male C57BL/6 mice fed a high-fat diet for 12 wk were treated with GLP-1 (200 μg/kg) or 0.9% saline for 4 wk. Fasting blood glucose and insulin and the expression of podocin, nephrin, phosphoinositide 3-kinase (PI3K), glucose transporter type (Glut4), and microtubule-associated protein 1A/1B-light chain 3 (LC3) were assayed. Glomerular morphology and podocyte foot structure were evaluated by periodic acid-Schiff staining and electron microscopy. Podocytes were treated with 150 nM GLP-1 and incubated with 400 μM palmitic acid (PA) for 12 h. The effect on autophagy was assessed by podocyte-specific Glut4 siRNA. Insulin resistance and autophagy were assayed by immunofluorescence and Western blotting. The high-fat diet resulted in weight gain, ectopic glomerular lipid accumulation, increased insulin resistance, and fusion of podophyte foot processes. The decreased translocation of Glut4 to the plasma membrane and excess autophagy seen in mice fed a high-fat diet and in PA-treated cultured podocytes were attenuated by GLP-1. Podocyte-specific Glut4 siRNA promoted autophagy, and rapamycin-enhanced autophagy worsened the podocyte injury caused by PA. Excess autophagy in podocytes was induced by inhibition of Glut4 translocation to the plasma membrane and was involved in the pathology of ORG. GLP-1 restored insulin sensitivity and ameliorated renal injury by decreasing the level of autophagy.

Protective Effects of Glucagon-Like Peptide-1 Analog on Renal Tubular Injury in Mice on High-Fat Diet

Aims: The study aimed to investigate the renoprotective effect of glucagon-like peptide-1 (GLP-1) against renal tubular injury in C57BL/6 mice induced by a high-fat diet (HFD). Methods: Twenty C57BL/6 mice were fed HFD for 12 weeks. Ten of these mice were treated with GLP-1 at 200 µg/kg subcutaneously twice daily for 4 weeks (HFDG group), and the other ten mice received vehicle only (HFD group). Ten mice fed standard rodent chow served as controls (Con group). Body weight, kidney weight, food intake, and systolic blood pressure were measured. The expression of endoplasmic reticulum stress (ERS) markers (BIP, p-eIF2α, ATF4, and CHOP) and apoptosis in the kidney were examined utilizing western blotting, immunohistochemistry and TUNEL, respectively. Angiotensin II and angiotensin II type 1 receptor (AT1R) were examined by ELISA. Human proximal tubule epithelial cells (HK2) were treated with GLP-1(150 nM) followed by treatment with palmitic acid (500 nM [PA]) for 24 h. HK2 cells treated with BSA were used as controls. The protein levels of ERS markers, apoptosis-associated protein, and AT1R were measured by western blotting. Results: Increase of body weight, food intake, and systolic blood pressure was less pronounced in GLP-1 treated HFDG mice compared to HFD mice. The levels of ERS markers (BIP, p-eIF2α, ATF4, and CHOP) and apoptosis decreased following GLP-1 treatment in vivo and in vitro (p<0.05). Increased AT1R induced by HFD and PA were blocked with GLP-1 treatment. In contrast, the level of angiotensin II after GLP-1 treatment was not significantly different between the HFD and HFDG mice. Conclusion: The study indicated that saturated fatty acids induced ERS and apoptosis in the kidney and increased AT1R expression. GLP-1 treatment exerted renoprotective effects against saturated fatty acid-induced kidney tubular cell ERS and apoptosis together with inhibition of AT1R expression in vivo and in vitro.

Bariatric Surgery: Pathophysiology and Outcomes

Diabetes mellitus and obesity are closely interrelated and pose a major burden on health care in terms of morbidity and mortality. Weight loss has favorable metabolic benefits for glycemic control and improvement of metabolic syndrome. Bariatric surgery (BS) is the most effective treatment for weight loss with durable results as compared to lifestyle modification. BS procedures have been associated with significant reduction in abdominal obesity, metabolic syndrome components, and glycemic control requiring fewer medications. Long-term risks of surgery include nutritional deficiencies, osteoporosis, bone fractures, and hyperinsulinemic hypoglycemia, which need to be carefully balanced with metabolic benefits for individual patients.

Improved glucose metabolism following bariatric surgery is associated with increased circulating bile acid concentrations and remodeling of the gut microbiome

Clinical studies have indicated that circulating bile acid (BA) concentrations increase following bariatric surgery, especially following malabsorptive procedures such as Roux-en-Y gastric bypasses (RYGB). Moreover, total circulating BA concentrations in patients following RYGB are positively correlated with serum glucagon-like peptide-1 concentrations and inversely correlated with postprandial glucose concentrations. Overall, these data suggest that the increased circulating BA concentrations following bariatric surgery - independently of calorie restriction and body-weight loss - could contribute, at least in part, to improvements in insulin sensitivity, incretin hormone secretion, and postprandial glycemia, leading to the remission of type-2 diabetes (T2DM). In humans, the primary and secondary BA pool size is dependent on the rate of biosynthesis and the enterohepatic circulation of BAs, as well as on the gut microbiota, which play a crucial role in BA biotransformation. Moreover, BAs and gut microbiota are closely integrated and affect each other. Thus, the alterations in bile flow that result from anatomical changes caused by bariatric surgery and changes in gut microbiome may influence circulating BA concentrations and could subsequently contribute to T2DM remission following RYGB. Research data coming largely from animal and cell culture models suggest that BAs can contribute, via nuclear farnezoid X receptor (FXR) and membrane G-protein-receptor (TGR-5), to beneficial effects on glucose metabolism. It is therefore likely that FXR, TGR-5, and BAs play a similar role in glucose metabolism following bariatric surgery in humans. The objective of this review is to discuss in detail the results of published studies that show how bariatric surgery affects glucose metabolism and subsequently T2DM remission.

Mechanisms underpinning remission of albuminuria following bariatric surgery

PURPOSE OF REVIEW

Albuminuria is a biomarker of renal injury commonly used to monitor progression of diabetic kidney disease. The appearance of excess albumin in the urine reflects alterations in the structure and permeability of the glomerular filtration barrier. The present article summarizes the clinical evidence base for remission of albuminuria after bariatric surgery. It furthermore focuses on how beneficial impacts on glomerular podocyte structure and function may explain this phenomenon.

RECENT FINDINGS

A coherent clinical evidence base is emerging demonstrating remission of albuminuria following bariatric surgery in patients with obesity and diabetes. The impaired metabolic milieu in diabetic kidney disease drives podocyte dedifferentiation and death through glucotoxic, lipotoxic proinflammatory, and pressure-related stress. Improvements in these parameters after surgery correlate with improvements in albuminuria and preclinical studies provide mechanistic data that support the existence of cause-effect relationship.

SUMMARY

The benefits of bariatric surgery extend beyond weight loss in diabetes to encompass beneficial effects on diabetic renal injury. Attenuation of the toxic metabolic milieu that the podocyte is exposed to postbariatric surgery suggests that the restitution of podocyte health is a key cellular event underpinning remission of albuminuria.

Weight loss interventions and progression of diabetic kidney disease

Progressive renal impairment (diabetic kidney disease (DKD)) occurs in upwards of 40 % of patients with obesity and type 2 diabetes mellitus (T2DM) and is a cause of significant morbidity and mortality. Means of attenuating the progression of DKD focus on amelioration of risk factors. Visceral obesity is implicated as a causative agent in impaired metabolic and cardiovascular control in T2DM, and various approaches primarily targeting weight have been examined for their impact on markers of renal injury and dysfunction in DKD. The current report summarises the evidence base for the impact of surgical, lifestyle and pharmacological approaches to weight loss on renal end points in DKD. The potential for a threshold of weight loss more readily achievable by surgical intervention to be a prerequisite for renal improvement is highlighted. Comparing efficacious non-surgical weight loss strategies with surgical strategies in appropriately powered and controlled prospective studies is a priority for the field.

Central 5-HT neurotransmission modulates weight loss following gastric bypass surgery in obese individuals

The cerebral serotonin (5-HT) system shows distinct differences in obesity compared with the lean state. Here, it was investigated whether serotonergic neurotransmission in obesity is a stable trait or changes in association with weight loss induced by Roux-in-Y gastric bypass (RYGB) surgery. In vivo cerebral 5-HT2A receptor and 5-HT transporter binding was determined by positron emission tomography in 21 obese [four men; body mass index (BMI), 40.1 ± 4.1 kg/m(2)] and 10 lean (three men; BMI, 24.6 ± 1.5 kg/m(2)) individuals. Fourteen obese individuals were re-examined after RYGB surgery. First, it was confirmed that obese individuals have higher cerebral 5-HT2A receptor binding than lean individuals. Importantly, we found that higher presurgical 5-HT2A receptor binding predicted greater weight loss after RYGB and that the change in 5-HT2A receptor and 5-HT transporter binding correlated with weight loss after RYGB. The changes in the 5-HT neurotransmission before and after RYGB are in accordance with a model wherein the cerebral extracellular 5-HT level modulates the regulation of body weight. Our findings support that the cerebral 5-HT system contributes both to establish the obese condition and to regulate the body weight in response to RYGB.