The effect of ileal interposition surgery on enteroendocrine cell numbers in the UC Davis type 2 diabetes mellitus rat

The effects of curcumin and sertraline on stress-induced changes in the stomach tissues of rats

Exposure to stressors can cause functional disorders and structural damage to the stomach. Sertraline (SER) is an antidepressant and curcumin (CUR) is a natural compound with many properties. The current study aimed to investigate the impacts of stress, SER, and CUR on the stomach tissue using stereological methods. In total, 24 male and 24 female Sprague-Dawley rats were divided into four groups. In the control group, the rats were not exposed to stress. However, the animals in stress, SER and, CUR groups were exposed to daily stress and were orally fed with distilled water, SER (10 mg/kg/day), and CUR (100 mg/kg/day), respectively. The volume, surface area, and number of nerve, parietal, and chief cells were evaluated by stereological methods. Results showed that stress increased the stomach and its mucosa and submucosa volumes, while it decreased the surface area of the mucosa. Furthermore, this disorder increased the number of neurons in the submucosa and myenteric plexuses while it decreased the number of parietal and chief cells. However, treating stressed rats with SER or CUR could prevent these changes. The results showed that the consumption of SER or CUR could be used as a preventive or adjunctive treatment for stressful situations.

Colonic Myenteric Plexus Neurodegeneration and Minor Colon Inflammation in Trimethyltin-induced Rat Model of Neurodegeneration

Gastrointestinal symptoms are common health problems found during aging and neurodegenerative diseases. Trimethyltin-induced rat is known as an animal model of hippocampal degeneration with no data on enteric neurodegeneration. This study aimed to investigate the effect of trimethyltin (TMT) induction on the gastrointestinal tract. A 28-day animal study with male Sprague-Dawley rats (3 months old, 150-200 g) given a single TMT injection (8 mg/kg body weight, intraperitoneal) was conducted. The number of neurons in the colonic myenteric plexus was measured using stereological estimation. Histological scoring of colon inflammation, immunohistochemistry of tumor necrosis factor-α (TNF-α), and quantitative PCR were conducted. This study showed neuronal loss in the colonic myenteric plexus of TMT-induced rat model of neurodegeneration. Minor colon inflammation characterized by inflammatory cell infiltration and slightly higher expression of TNF-α in the colon mucosa were observed in the TMT-induced rat. However, the gut microbiota composition of the TMT-induced rat was not different from that of the control rats. This study demonstrates that TMT induces colonic myenteric plexus neurodegeneration and minor colon inflammation, which suggests the potential of this animal model to elucidate the communication between the gastrointestinal tract and central nervous system in neurodegenerative diseases.

Zucker Diabetic Sprague Dawley rat (ZDSD): type 2 diabetes translational research model

New Findings

What is the topic of this review?

The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is in the early adoption phase of use by researchers in the fields of diabetes, including prediabetes, obesity and metabolic syndrome. It is essential that physiology researchers choose preclinical models that model human type 2 diabetes appropriately and are aware of the limitations on experimental design.

What advances does it highlight?

Our review of the scientific literature finds that although sex, age and diets contribute to variability, the ZDSD phenotype and disease progression model the characteristics of humans who have prediabetes and diabetes, including co‐morbidities.

Abstract

Type 2 diabetes (T2D) is a prevalent disease and a significant concern for global population health. For persons with T2D, clinical treatments target not only the characteristics of hyperglycaemia and insulin resistance, but also co‐morbidities, such as obesity, cardiovascular and renal disease, neuropathies and skeletal bone conditions. The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is a rodent model developed for experimental studies of T2D. We reviewed the scientific literature to highlight the characteristics of T2D development and the associated phenotypes, such as metabolic syndrome, cardiovascular complications and bone and skeletal pathologies in ZDSD rats. We found that ZDSD phenotype characteristics are independent of leptin receptor signalling. The ZDSD rat develops prediabetes, then progresses to overt diabetes that is accelerated by introduction of a timed high‐fat diet. In male ZDSD rats, glycated haemoglobin (HbA1c) increases at a constant rate from 7 to >30 weeks of age. Diabetic ZDSD rats are moderately hypertensive compared with other rat strains. Diabetes in ZDSD rats leads to endothelial dysfunction in specific vasculatures, impaired wound healing, decreased systolic and diastolic cardiac function, neuropathy and nephropathy. Changes to bone composition and the skeleton increase the risk of bone fractures. Zucker Diabetic‐Sprague Dawley rats have not yet achieved widespread use by researchers. We highlight sex‐related differences in the ZDSD phenotype and gaps in knowledge for future studies. Overall, scientific data support the premise that the phenotype and disease progression in ZDSD rats models the characteristics in humans. We conclude that ZDSD rats are an advantageous model to advance understanding and discovery of treatments for T2D through preclinical research.

Ileal microbial shifts after Roux-en-Y gastric bypass orchestrate changes in glucose metabolism through modulation of bile acids and L-cell adaptation

Roux-en-Y gastric bypass (RYGB)-induced glycemic improvement is associated with increases in glucagon-like-peptide-1 (GLP-1) secreted from ileal L-cells. We analyzed changes in ileal bile acids and ileal microbial composition in diet-induced-obesity rats after RYGB or sham surgery to elucidate the early and late effects on L-cells and glucose homeostasis. In early cohorts, there were no significant changes in L-cell density, GLP-1 or glucose tolerance. In late cohorts, RYGB demonstrated less weight regain, improved glucose tolerance, increased L-cell density, and increased villi height. No difference in the expression of GLP-1 genes was observed. There were lower concentrations of ileal bile acids in the late RYGB cohort. Microbial analysis demonstrated decreased alpha diversity in early RYGB cohorts which normalized in the late group. The early RYGB cohorts had higher abundances of Escherichia-Shigella but lower abundances of Lactobacillus, Adlercreutzia, and Proteus while the late cohorts demonstrated higher abundances of Escherichia-Shigella and lower abundances of Lactobacillus. Shifts in Lactobacillus and Escherichia-Shigella correlated with decreases in multiple conjugated bile acids. In conclusion, RYGB caused a late and substantial increase in L-cell quantity with associated changes in bile acids which correlated to shifts in Escherichia-Shigella and Lactobacillus. This proliferation of L-cells contributed to improved glucose homeostasis.

Progression of diabetes is associated with changes in the ileal transcriptome and ileal-colon morphology in the UC Davis Type 2 Diabetes Mellitus rat

Deterioration in glucose homeostasis has been associated with intestinal dysbiosis, but it is not known how metabolic dysregulation alters the gastrointestinal environment. We investigated how the progression of diabetes alters ileal and colonic epithelial mucosal structure, microbial abundance, and transcript expression in the University of California Davis Type 2 Diabetes Mellitus (UCD-T2DM) rat model. Male UCD-T2DM rats (age ~170 days) were included if <1-month (n = 6, D1M) or 3-month (n = 6, D3M) post-onset of diabetes. Younger nondiabetic UCD-T2DM rats were included as a nondiabetic comparison (n = 6, ND, age ~70 days). Ileum villi height/crypt depths and colon crypt depths were assessed by histology. Microbial abundance of colon content was measured with 16S rRNA sequencing. Ileum and colon transcriptional abundances were analyzed using RNA sequencing. Ileum villi height and crypt depth were greater in D3M rats compared to ND. Colon crypt depth was greatest in D3M rats compared to both ND and D1M rats. Colon abundances of Akkermansia and Muribaculaceae were lower in D3M rats relative to D1M, while Oscillospirales, Phascolarctobacterium, and an unidentified genus of Lachnospiraceae were higher. Only two transcripts were altered by diabetes advancement within the colon; however, 2039 ileal transcripts were altered. Only colonic abundances of Sptlc3, Enpp7, Slc7a15, and Kctd14 had more than twofold changes between D1M and D3M rats. The advancement of diabetes in the UCD-T2DM rat results in a trophic effect on the mucosal epithelia and was associated with regulation of gastrointestinal tract RNA expression, which appears more pronounced in the ileum relative to the colon.

The altered enteroendocrine reportoire following roux-en-Y-gastric bypass as an effector of weight loss and improved glycaemic control

The alarming rise in obesity and relative lack of pharmacotherapies to treat, what is becoming a global epidemic, has necessitated that an increasing number of bariatric procedures be performed. Several surgical techniques have been developed during the last 50 years and the advent of laparoscopic surgery has increased the safety and efficacy of these procedures. Bariatric surgery is by a substantial margin, the most efficacious means of achieving sustained weight loss maintenance in patients with obesity. Roux-en-Y gastric bypass surgery (RYGB) elicits the most favourable metabolic outcomes with attendant benefits for type 2 diabetes and, cardiovascular disease as well as endocrine disorders and cancers in females. RYGB is the most extensively studied bariatric procedure regarding mechanism of action. In this review we catalogue the multiple alterations in secretion of gut hormones (ghrelin, obestatin, cholecystokinin, GLP-1, PYY, GIP, oxyntomodulin, glicentin and GLP-2) occurring after RYGB and summarise evidence indicating that these changes play a role in the reduction of food intake and improvements in glucose homeostasis.

Ileal Transposition (IT) Surgery Changing the Ultrastructure of the Transposed Segment as well as Jejunum. Histomorphometric and Electron Microscopy Analysis

Objective

Ileal transposition (IT) procedure leads to higher secretion of incretin hormones what is associated with a beneficial metabolic effect. However, IT will also have an influence on the related jejunum and ileum function. The aim of this research was to investigate the morphology of the jejunum and transposed ileum with the use of light and transmission electron microscopy (TEM) in order to determine the local alternations in the intestine resulting from the transposition.

Methods

Twenty male, 8-week-old, obese Zucker rats underwent IT and six of them sham surgery. To compare both groups, the transection was made at all corresponding ileum positions among both groups of animals. The ileal anastomoses among the rats of sham procedure were subsequently formed accordingly without IT. Three months following the surgery, the tissue samples of jejunum and ileum were harvested.

Results

A significant increase in villus length, a decrease in the crypt depth, and an increased thickness of mucosa-muscularis-serosa (MMS) as well as cellular hyperplasia, with increased mitochondrial density of the transposed ileum segment, were observed among the group of rats which underwent IT comparing to the ones undergoing sham surgery. In rats undergoing IT, microvillus degeneration in jejunum regions was observed.

Conclusions

Ileal transposition alters the morphology and ultrastructure of the ileum as well as the jejunum. Given that the microvillus membrane represents an important aspect of the enterocyte functions, a further biochemical and molecular research is necessary in order to assess whether the observed changes are beneficial or not and to explore the phenomenon of gut adaptability after metabolic surgery.

Can Sertraline and Nortriptyline Protect the Neurons in Submucosal and Myenteric Plexuses of Rat's Colon Against Stress?

BACKGROUND

The colon is partly controlled by myenteric and submucosal plexuses, which respond to stress and lead to some gastrointestinal disorders. These plexuses play roles in irritable bowel syndrome. Patients suffering from this syndrome can be treated with some antidepressants, including sertraline and nortriptyline.

AIMS

The primary aim of study was to compare the effect of a sertraline and a nortriptyline on the structural changes of the enteric neurons after stress exposure in both sexes. The secondary objectives were to evaluate the effects of stress on the submucosal and myenteric plexuses.

METHODS

Male and female Sprague-Dawley rats were assigned to four subgroups. The first subgroup received no stress. The other three subgroups received chronic variable stress (CVS) and were given phosphate buffer, sertraline (10 mg/kg/day), or nortriptyline (10 mg/kg/day). After 45 days, the neuron number in their colon plexuses was estimated using the stereologic method.

RESULTS

The number of neurons increased by 40-51% in the submucosal plexus and by 57-69% in the myenteric plexus in the CVS group compared with the control group (p < 0.002) without any sex preference. The increment was significantly higher in the myenteric plexus than in the submucosal plexus (p < 0.05). Moreover, co-treatment of stressed rats with sertraline and nortriptyline could prevent the cellular hyperplasia of the plexuses, with more effective action for sertraline (p < 0.02).

CONCLUSIONS

Stress exposure for 45 days induced hyperplasia of the colon's enteric plexuses in both sexes. However, these drugs could prevent the changes, with a more effective action for sertraline.

Adipose depot-specific effects of ileal interposition surgery in UCD-T2D rats: unexpected implications for obesity and diabetes

Ileal interposition (IT) surgery delays the onset of diabetes in a rat model of type-2 diabetes (UCD-T2DM). Here, to gain a deeper understanding of the molecular events underlying the effects of IT surgery, we examined the changes in the proteome of four white adipose depots (retroperitoneal, mesenteric, inguinal, and epididymal) and plasma-free fatty acid profile in pre-diabetic rats 1.5 months following IT or sham surgery. The IT-mediated changes were exerted mainly in mesenteric fat and spanned from delayed adipocyte maturation to a neuroendocrine remodeling. Conversely, inguinal, retroperitoneal, and epididymal depots showed opposite trends consistent with increased adipocyte maturation and adipogenesis development prior to overt signs of diabetes, probably orchestrated by peroxisome proliferator-activated receptor gamma signaling and higher plasma n-6/n-3 free fatty acid ratios. The resulting scenario suggests a targeted use of surgical strategies that seek to delay or improve diabetes in order to manipulate adipose depot-specific responses to maximize the duration and beneficial effects of the surgery.

Bile acids and bariatric surgery

Bariatric surgery, specifically Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG), are the most effective and durable treatments for morbid obesity and potentially a viable treatment for type 2 diabetes (T2D). The resolution rate of T2D following these procedures is between 40 and 80% and far surpasses that achieved by medical management alone. The molecular basis for this improvement is not entirely understood, but has been attributed in part to the altered enterohepatic circulation of bile acids. In this review we highlight how bile acids potentially contribute to improved lipid and glucose homeostasis, insulin sensitivity and energy expenditure after these procedures. The impact of altered bile acid levels in enterohepatic circulation is also associated with changes in gut microflora, which may further contribute to some of these beneficial effects. We highlight the beneficial effects of experimental surgical procedures in rodents that alter bile secretory flow without gastric restriction or altering nutrient flow. This information suggests a role for bile acids beyond dietary fat emulsification in altering whole body glucose and lipid metabolism strongly, and also suggests emerging roles for the activation of the bile acid receptors farnesoid x receptor (FXR) and G-protein coupled bile acid receptor (TGR5) in these improvements. The limitations of rodent studies and the current state of our understanding is reviewed and the potential effects of bile acids mediating the short- and long-term metabolic improvements after bariatric surgery is critically examined.

The endogenous preproglucagon system is not essential for gut growth homeostasis in mice

OBJECTIVE

The prevalence of obesity and related co-morbidities is reaching pandemic proportions. Today, the most effective obesity treatments are glucagon-like peptide 1 (GLP-1) analogs and bariatric surgery. Interestingly, both intervention paradigms have been associated with adaptive growth responses in the gut; however, intestinotrophic mechanisms associated with or secondary to medical or surgical obesity therapies are poorly understood. Therefore, the objective of this study was to assess the local basal endogenous and pharmacological intestinotrophic effects of glucagon-like peptides and bariatric surgery in mice.

METHODS

We used in situ hybridization to provide a detailed and comparative anatomical map of the local distribution of GLP-1 receptor (Glp1r), GLP-2 receptor (Glp2r), and preproglucagon (Gcg) mRNA expression throughout the mouse gastrointestinal tract. Gut development in GLP-1R-, GLP-2R-, or GCG-deficient mice was compared to their corresponding wild-type controls, and intestinotrophic effects of GLP-1 and GLP-2 analogs were assessed in wild-type mice. Lastly, gut volume was determined in a mouse model of vertical sleeve gastrectomy (VSG).

RESULTS

Comparison of Glp1r, Glp2r, and Gcg mRNA expression indicated a widespread, but distinct, distribution of these three transcripts throughout all compartments of the mouse gastrointestinal tract. While mice null for Glp1r or Gcg showed normal intestinal morphology, Glp2r-/- mice exhibited a slight reduction in small intestinal mucosa volume. Pharmacological treatment with GLP-1 and GLP-2 analogs significantly increased gut volume. In contrast, VSG surgery had no effect on intestinal morphology.

CONCLUSION

The present study indicates that the endogenous preproglucagon system, exemplified by the entire GCG gene and the receptors for GLP-1 and GLP-2, does not play a major role in normal gut development in the mouse. Furthermore, elevation in local intestinal and circulating levels of GLP-1 and GLP-2 achieved after VSG has limited impact on intestinal morphometry. Hence, although exogenous treatment with GLP-1 and GLP-2 analogs enhances gut growth, the contributions of endogenously-secreted GLP-1 and GLP-2 to gut growth may be more modest and highly context-dependent.

Attenuated secretion of glucose-dependent insulinotropic polypeptide (GIP) does not alleviate hyperphagic obesity and insulin resistance in ob/ob mice

OBJECTIVE

Glucose-dependent insulinotropic polypeptide (GIP) is released during meals and promotes nutrient uptake and storage. GIP receptor knockout mice are protected from diet induced weight gain and thus GIP antagonists have been proposed as a treatment for obesity. In this study, we assessed the role of GIP in hyperphagia induced obesity and metabolic abnormalities in leptin deficient (Lep^ob/ob) mice.

METHODS

We crossbred GIP-GFP knock-in homozygous mice (GIP^gfp/gfp) that have complete GIP knockout, and mice heterozygous for the ob mutation (Lep^ob/+) mice to generate Lep^ob/+/GIP^+/+, Lep^ob/ob/GIP^+/+, and Lep^ob/ob/GIP^gfp/gfp mice. Male animals were weighed weekly and both oral glucose and insulin tolerance testing were performed to assess glucose homeostasis and circulating profiles of GIP and insulin. Body composition was evaluated by computerized tomography (CT) scan and analyses of indirect calorimetry and locomotor activity were performed.

RESULTS

Postprandial GIP levels were markedly elevated in Lep^ob/ob/GIP^+/+ mice compared to Lep^ob/+/GIP^+/+ controls and were undetectable in Lep^ob/ob/GIP^gfp/gfp mice. Insulin levels were equivalently elevated in both Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice compared to controls at 8 weeks of age but the hyperinsulinemia was marginally reduced in Lep^ob/ob/GIP^gfp/gfp by 21 weeks, in association with amelioration of glucose intolerance. Both Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice remained equivalently insulin resistant. Body weight gain and subcutaneous and visceral fat volume of both Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice were significantly higher than that of Lep^ob/+/GIP^+/+ mice, while no significant differences were seen between Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice. Locomotor activity and energy expenditure were decreased in both Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice compared to control Lep^ob/+/GIP^+/+ mice, while no significant differences were seen between Lep^ob/ob/GIP^+/+ and Lep^ob/ob/GIP^gfp/gfp mice. There was no significant difference in fat oxidation among the three groups. Fat content in liver was significantly lower in Lep^ob/ob/GIP^gfp/gfp compared to Lep^ob/ob/GIP^+/+ mice, while that of control Lep^ob/+/GIP^+/+ mice was the lowest.

CONCLUSIONS

Our results indicate that GIP knockout does not prevent excess weight gain and metabolic derangement in hyperphagic leptin deficient mice.

Recent advances in metabolic and bariatric surgery

Obesity and its associated medical conditions continue to increase and add significant burden to patients, as well as health-care systems, worldwide. Bariatric surgery is the most effective treatment for severe obesity and its comorbidities, and resolution of diabetes is weight loss-independent in the case of some operations. Although these weight-independent effects are frequently described clinically, the mechanisms behind them are not well understood and remain an intense area of focus in the growing field of metabolic and bariatric surgery. Perceptions of the mechanisms responsible for the beneficial metabolic effects of metabolic/bariatric operations have shifted from being mostly restrictive and malabsorption over the last 10 to 15 years to being more neuro-hormonal in origin. In this review, we describe recent basic and clinical findings of the major clinical procedures (adjustable gastric banding, vertical sleeve gastrectomy, Roux-en-Y gastric bypass, and biliopancreatic diversion) as well as other experimental procedures (ileal interposition and bile diversion) that recapitulate many of the metabolic effects of these complex operations in a simpler fashion. As the role of bile acids and the gut microbiome on metabolism is becoming increasingly well described, their potential roles in these improvements following metabolic surgery are becoming better appreciated. Bile acid and gut microbiome changes, in light of recent developments, are discussed in the context of these surgical procedures, as well as their implications for future study.

In Vivo Models for Incretin Research: From the Intestine to the Whole Body

Incretin hormones are produced by enteroendocrine cells (EECs) in the intestine in response to ingested nutrient stimuli. The incretin effect is defined as the difference in the insulin secretory response between the oral glucose tolerance test and an isoglycemic intravenous glucose infusion study. The pathophysiology of the decreased incretin effect has been studied as decreased incretin sensitivity and/or β-cell dysfunction per se. Interestingly, robust increases in endogenous incretin secretion have been observed in many types of metabolic/bariatric surgery. Therefore, metabolic/bariatric surgery has been extensively studied for incretin physiology, not only the hormones themselves but also alterations in EECs distribution and genetic expression levels of gut hormones. These efforts have given us an enormous understanding of incretin biology from synthesis to in vivo behavior. Further innovative studies are needed to determine the mechanisms and targets of incretin hormones.

Improvements of Glucose and Lipid Metabolism After Jejuno-ileal Circuit Procedure in a Non-obese Diabetic Rat Model

BACKGROUND

In a recent study, we showed a jejuno-ileal circuit (JIC) procedure that effectively improved glucose homeostasis, but the intrinsic mechanism requires further studies. Furthermore, the role of JIC in lipid metabolism is also unknown. Given that adiposity aggravates insulin sensitivity, we hypothesize that the JIC procedure improves fat metabolism and thus further contributes to diabetic remission. The aim of this study was to investigate the effects of JIC surgery on lipid metabolism and glucose homeostasis in a non-obese diabetic rat model.

METHODS

Fourteen high-fat diet and low-dose streptozotocin-induced diabetic rats were randomly divided into JIC and sham-JIC groups. Body weight, food intake, glucose tolerance, insulin resistance, serum lipid parameters, glucagon-like peptide 1 (GLP-1), and adipose-derived hormones were measured. At 12 weeks postoperatively, the expressions of hepatic fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC) were measured by Western blot. The lipid content of liver was assessed by hematoxylin-eosin staining and Oil Red O staining. The enteroendocrine cells in the distal ileum were examined by immunohistochemical staining.

RESULTS

Relative to the sham group, the JIC rats exhibited significant improvements in glucose tolerance, insulin resistance, and dyslipidemia without weight loss, showing increased GLP-1 and adiponectin and decreased leptin. JIC also reduced the expression of FAS and ACC in the liver, exhibited improved hepatic fat content, and raised the levels of GLP-1 and chromogranin A in the distal gut.

CONCLUSIONS

JIC alleviated lipometabolic disorders in hyperglycemic rats, which may contribute to the amelioration of insulin sensitivity and glycemic control.

mTOR disruption causes intestinal epithelial cell defects and intestinal atrophy postinjury in mice

Intestinal stem cells (ISCs) drive small intestinal epithelial homeostasis and regeneration. Mechanistic target of rapamycin (mTOR) regulates stem and progenitor cell metabolism and is frequently dysregulated in human disease, but its physiologic functions in the mammalian small intestinal epithelium remain poorly defined. We disrupted the genes mTOR, Rptor, Rictor, or both Rptor and Rictor in mouse ISCs, progenitors, and differentiated intestinal epithelial cells (IECs) using Villin-Cre. Mutant tissues and wild-type or heterozygous littermate controls were analyzed by histologic immunostaining, immunoblots, and proliferation assays. A total of 10 Gy irradiation was used to injure the intestinal epithelium and induce subsequent crypt regeneration. We report that mTOR supports absorptive enterocytes and secretory Paneth and goblet cell function while negatively regulating chromogranin A-positive enteroendocrine cell number. Through additional Rptor, Rictor, and Rptor/Rictor mutant mouse models, we identify mechanistic target of rapamycin complex 1 as the major IEC regulatory pathway, but mechanistic target of rapamycin complex 2 also contributes to ileal villus maintenance and goblet cell size. Homeostatic adult small intestinal crypt cell proliferation, survival, and canonical wingless-int (WNT) activity are not mTOR dependent, but Olfm4(+) ISC/progenitor population maintenance and crypt regeneration postinjury require mTOR. Overall, we conclude that mTOR regulates multiple IEC lineages and promotes stem and progenitor cell activity during intestinal epithelium repair postinjury.

The role of gut adaptation in the potent effects of multiple bariatric surgeries on obesity and diabetes

Bariatric surgical procedures such as vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) are the most potent treatments available to produce sustained reductions in body weight and improvements in glucose regulation. While traditionally these effects are attributed to mechanical aspects of these procedures, such as restriction and malabsorption, a growing body of evidence from mouse models of these procedures points to physiological changes that mediate the potent effects of these surgeries. In particular, there are similar changes in gut hormone secretion, bile acid levels, and composition after both of these procedures. Moreover, loss of function of the nuclear bile acid receptor (FXR) greatly diminishes the effects of VSG. Both VSG and RYGB are linked to profound changes in the gut microbiome that also mediate at least some of these surgical effects. We hypothesize that surgical rearrangement of the gastrointestinal tract results in enteroplasticity caused by the high rate of nutrient presentation and altered pH in the small intestine that contribute to these physiological effects. Identifying the molecular underpinnings of these procedures provides new opportunities to understand the relationship of the gastrointestinal tract to obesity and diabetes as well as new therapeutic strategies to harness the effectiveness of surgery with less-invasive approaches.

Laparoscopic diverted resleeve with ileal transposition for failed laparoscopic sleeve gastrectomy: a case report

Laparoscopic sleeve gastrectomy (LSG) recently gained popularity for the treatment of obesity and related co-morbidities. With the increasing number of bariatric operations, the requirement for redo or revision bariatric surgery seems to be increasing. In the present case, a 50-year-old female patient with failed LSG who underwent laparoscopic resleeve, duodenal diversion, and ileal transposition is presented. Her metabolic and biochemical parameters were found to be improved significantly after 18 months. To the best of our knowledge, this is the first report of a case treated with this method in the literature.