Roles of the Gut in Glucose Homeostasis

The impact of surgery and oncological treatment on risk of type 2 diabetes onset in patients with colorectal cancer: nationwide cohort study in Denmark

Background

Comorbidity with type 2 diabetes (T2D) results in worsening of cancer-specific and overall prognosis in colorectal cancer (CRC) patients. The treatment of CRC per se may be diabetogenic. We assessed the impact of different types of surgical cancer resections and oncological treatment on risk of T2D development in CRC patients.

Methods

We developed a population-based cohort study including all Danish CRC patients, who had undergone CRC surgery between 2001 and 2018. Using nationwide register data, we identified and followed patients from date of surgery and until new onset of T2D, death, or end of follow-up.

Results

In total, 46,373 CRC patients were included and divided into six groups according to type of surgical resection: 10,566 Right-No-Chemo (23%), 4645 Right-Chemo (10%), 10,151 Left-No-Chemo (22%), 5257 Left-Chemo (11%), 9618 Rectal-No-Chemo (21%), and 6136 Rectal-Chemo (13%). During 245,466 person-years of follow-up, 2556 patients developed T2D. The incidence rate (IR) of T2D was highest in the Left-Chemo group 11.3 (95% CI: 10.4-12.2) per 1000 person-years and lowest in the Rectal-No-Chemo group 9.6 (95% CI: 8.8-10.4). Between-group unadjusted hazard ratio (HR) of developing T2D was similar and non-significant. In the adjusted analysis, Rectal-No-Chemo was associated with lower T2D risk (HR 0.86 [95% CI 0.75-0.98]) compared to Right-No-Chemo.For all six groups, an increased level of body mass index (BMI) resulted in a nearly twofold increased risk of developing T2D.

Conclusions

This study suggests that postoperative T2D screening should be prioritised in CRC survivors with overweight/obesity regardless of type of CRC treatment applied.

Funding

The Novo Nordisk Foundation (NNF17SA0031406); TrygFonden (101390; 20045; 125132).

Causal effects of inflammatory bowel disease on risk of type 2 diabetes: a two-sample multivariable Mendelian randomization study

AIM

This study aimed to explore the causal association between inflammatory bowel disease (IBD) and the risk of type 2 diabetes (T2D) based on a two-sample Mendelian randomization (MR) study.

METHODS

Summary single nucleotide polymorphism (SNP)-phenotype association data were obtained from published two genome-wide association studies (GWAS) including SNPs related to IBD, UC, or CD in European participants (n = 71,997) and East Asian participants (n = 16,805). Two GWAS including SNPs associated with T2D included 655,666 Europeans and 433,540 East Asians. A series of screening processes were performed to select qualified instrumental SNPs strongly related to exposure. We applied the inverse variance weighted (IVW), the MR-Egger regression, and the weighted median to estimate the causal effects of IBD, ulcerative colitis (UC) or Crohn' disease (CD) on T2D. Cochran's Q test was conducted to evaluate the statistical heterogeneity between SNPs in the IVW method. The leave-one-out analysis was employed to assess whether the results were caused by any single SNP associated with IBD, UC, or CD. Odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

The IVW results demonstrated that IBD could increase the risk of T2D in the European population (OR = 1.0230, 95%CI: 1.0073-1.0390). UC was positively associated with the risk of T2D according to the weighted median (OR = 1.0274, 95%CI: 1.0009-1.0546) and IVW (OR = 1.0244, 95%CI: 1.0071-1.0421) results in the European population. The IVW results indicated that the CD was positively associated with the risk of T2D in the European population (OR = 1.0187, 95%CI: 1.0045-1.0330). In the East Asian population, there are no associations between the IBD, UC, or CD and the risk of T2D (all P > 0.05). MVMR results revealed that the causal effect UC on T2D was still statistically significant after including body mass index (BMI) or low-density lipoprotein (LDL).

CONCLUSION

IBD, UC, or CD had causal effects on the risk of T2D in the European population, which might provide evidence for the prevention of T2D in patients with IBD, UC, or CD.

Genome-wide cross-disease analyses highlight causality and shared biological pathways of type 2 diabetes with gastrointestinal disorders

Studies suggest links between diabetes and gastrointestinal (GI) traits; however, their underlying biological mechanisms remain unclear. Here, we comprehensively assess the genetic relationship between type 2 diabetes (T2D) and GI disorders. Our study demonstrates a significant positive global genetic correlation of T2D with peptic ulcer disease (PUD), irritable bowel syndrome (IBS), gastritis-duodenitis, gastroesophageal reflux disease (GERD), and diverticular disease, but not inflammatory bowel disease (IBD). We identify several positive local genetic correlations (negative for T2D - IBD) contributing to T2D's relationship with GI disorders. Univariable and multivariable Mendelian randomisation analyses suggest causal effects of T2D on PUD and gastritis-duodenitis and bidirectionally with GERD. Gene-based analyses reveal a gene-level genetic overlap between T2D and GI disorders and identify several shared genes reaching genome-wide significance. Pathway-based study implicates leptin (T2D - IBD), thyroid, interferon, and notch signalling (T2D - IBS), abnormal circulating calcium (T2D - PUD), cardiovascular, viral, proinflammatory and (auto)immune-mediated mechanisms in T2D and GI disorders. These findings support a risk-increasing genetic overlap between T2D and GI disorders (except IBD), implicate shared biological pathways with putative causality for certain T2D - GI pairs, and identify targets for further investigation.

Exercise Prescription for Postprandial Glycemic Management

The detrimental impacts of postprandial hyperglycemia on health are a critical concern, and exercise is recognized a pivotal tool in enhancing glycemic control after a meal. However, current exercise recommendations for managing postprandial glucose levels remain fairly broad and require deeper clarification. This review examines the existing literature aiming to offer a comprehensive guide for exercise prescription to optimize postprandial glycemic management. Specifically, it considers various exercise parameters (i.e., exercise timing, type, intensity, volume, pattern) for crafting exercise prescriptions. Findings predominantly indicate that moderate-intensity exercise initiated shortly after meals may substantially improve glucose response to a meal in healthy individuals and those with type 2 diabetes. Moreover, incorporating short activity breaks throughout the exercise session may provide additional benefits for reducing glucose response.

Comparative impact of Roux-en-Y gastric bypass, sleeve gastrectomy or diet alone on beta-cell function in insulin-treated type 2 diabetes patients

Although bariatric surgery is an effective treatment for type 2 diabetes by inducing weight loss and augmenting gut hormone secretion, the immediate effect on beta-cell function itself remains to be elucidated in type 2 diabetes. Therefore, a prospective, randomized trial was performed in 30 patients with insulin-treated type 2 diabetes and a body mass index ≥ 35 kg/m2. Patients were randomly assigned (1:1:1) to Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) in combination with protein-sparing modified fast (PSMF), or to PSMF alone. Eu- and hyperglycemic clamps were performed before and 3 weeks after surgery and/or PSMF initiation. The primary outcome was the evolution of insulin sensitivity and beta-cell function after surgery, calculated using the composite measures of glucose disposal rate, insulin secretion rate, and disposition index (DI). Results revealed that markers of insulin sensitivity increased similarly in all arms (p = 0.43). A higher marker for maximal beta-cell function was observed when comparing SG to PSMF (p = 0.007). The DI showed a clear positive evolution after RYGB and SG, but not after PSMF alone. Altogether, these findings indicate that bariatric surgery results in an immediate beta-cell function recovery in insulin-treated type 2 diabetes.

Duodenal enteroendocrine cells and GIP as treatment targets for obesity and type 2 diabetes

The duodenum is an important source of endocrine and paracrine signals controlling digestion and nutrient disposition, notably including the main incretin hormone glucose-dependent insulinotropic polypeptide (GIP). Bariatric procedures that prevent nutrients from contact with the duodenal mucosa are particularly effective interventions to reduce body weight and improve glycaemic control in obesity and type 2 diabetes. These procedures take advantage of increased nutrient delivery to more distal regions of the intestine which enhances secretion of the other incretin hormone glucagon-like peptide-1 (GLP-1). Preclinical experiments have shown that either an increase or a decrease in the secretion or action of GIP can decrease body weight and blood glucose in obesity and non-insulin dependent hyperglycaemia, but clinical studies involving administration of GIP have been inconclusive. However, a synthetic dual agonist peptide (tirzepatide) that exerts agonism at receptors for GIP and GLP-1 has produced marked weight-lowering and glucose-lowering effects in people with obesity and type 2 diabetes. This appears to result from chronic biased agonism in which the novel conformation of the peptide triggers enhanced signalling by the GLP-1 receptor through reduced internalisation while reducing signalling by the GIP receptor directly or via functional antagonism through increased internalisation and degradation.

Preservation of β-Cells as a Therapeutic Strategy for Diabetes

The preservation of pancreatic islet β-cells is crucial in diabetes mellitus, encompassing both type 1 and type 2 diabetes. β-cell dysfunction, reduced mass, and apoptosis are central to insufficient insulin secretion in both types. Research is focused on understanding β-cell characteristics and the factors regulating their function to develop novel therapeutic approaches. In type 1 diabetes (T1D), β-cell destruction by the immune system calls for exploring immunosuppressive therapies, non-steroidal anti-inflammatory drugs, and leukotriene antagonists. Islet transplantation, stem cell therapy, and xenogeneic transplantation offer promising strategies for type 1 diabetes treatment. For type 2 diabetes (T2D), lifestyle changes like weight loss and exercise enhance insulin sensitivity and maintain β-cell function. Additionally, various pharmacological approaches, such as cytokine inhibitors and protein kinase inhibitors, are being investigated to protect β-cells from inflammation and glucotoxicity. Bariatric surgery emerges as an effective treatment for obesity and T2D by promoting β-cell survival and function. It improves insulin sensitivity, modulates gut hormones, and expands β-cell mass, leading to diabetes remission and better glycemic control. In conclusion, preserving β-cells offers a promising approach to managing both types of diabetes. By combining lifestyle modifications, targeted pharmacological interventions, and advanced therapies like stem cell transplantation and bariatric surgery, we have a significant chance to preserve β-cell function and enhance glucose regulation in diabetic patients.

An extended minimal model of OGTT: estimation of α- and β-cell dysfunction, insulin resistance, and the incretin effect

Loss of insulin sensitivity, α- and β-cell dysfunction, and impairment in incretin effect have all been implicated in the pathophysiology of type 2 diabetes (T2D). Parsimonious mathematical models are useful in quantifying parameters related to the pathophysiology of T2D. Here, we extend the minimum model developed to describe the glucose-insulin-glucagon dynamics in the isoglycemic intravenous glucose infusion (IIGI) experiment to the oral glucose tolerance test (OGTT). The extended model describes glucose and hormone dynamics in OGTT including the contribution of the incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1), to insulin secretion. A new function describing glucose arrival from the gut is introduced. The model is fitted to OGTT data from eight individuals with T2D and eight weight-matched controls (CS) without diabetes to obtain parameters related to insulin sensitivity, β- and α-cell function. The parameters, i.e., measures of insulin sensitivity, a1, suppression of glucagon secretion, k1, magnitude of glucagon secretion, γ2, and incretin-dependent insulin secretion, γ3, were found to be different between CS and T2D with P values < 0.002, <0.017, <0.009, <0.004, respectively. A new rubric for estimating the incretin effect directly from modeling the OGTT is presented. The average incretin effect correlated well with the experimentally determined incretin effect with a Spearman rank test correlation coefficient of 0.67 (P < 0.012). The average incretin effect was found to be different between CS and T2D (P < 0.032). The developed model is shown to be effective in quantifying the factors relevant to T2D pathophysiology.NEW & NOTEWORTHY A new extended model of oral glucose tolerance test (OGTT) has been developed that includes glucagon dynamics and incretin contribution to insulin secretion. The model allows the estimation of parameters related to α- and β-cell dysfunction, insulin sensitivity, and incretin action. A new function describing the influx of glucose from the gut has been introduced. A new rubric for estimating the incretin effect directly from the OGTT experiment has been developed. The effect of glucose dose was also investigated.

Causal linkage between type 2 diabetes mellitus and inflammatory bowel disease: an integrated Mendelian randomization study and bioinformatics analysis

Background

Observational studies have indicated associations between type 2 diabetes mellitus (T2DM) and both colorectal cancer (CRC) and inflammatory bowel disease (IBD). However, the underlying causality and biological mechanisms between these associations remains unclear.

Methods

We conducted a bidirectional Mendelian randomization (MR) analysis employing summary statistics from genome-wide association studies involving European individuals. The inverse variance weighting (IVW) method was the primary method used to assess causality. Additionally, we applied MR Egger, Weighted median, Simple mode, and Weighted mode to evaluate the robustness of the results. Outliers were identified and eliminated using the MR-PRESSO, while the MR-Egger intercept was used to assess the horizontal pleiotropic effects of single nucleotide polymorphisms (SNPs). The heterogeneity was evaluated using the Cochrane Q test, and sensitivity analysis was performed using leave-one-out method. The F statistic was calculated to evaluate weak instrumental variable bias. Finally, a pilot bioinformatics analysis was conducted to explore the underlying biological mechanisms between T2DM and IBD/UC.

Results

The IVW results demonstrated that T2DM significantly reduced risks of IBD (OR=0.885, 95% CI: 0.818-0.958, P=0.002) and ulcerative colitis (UC) (OR=0.887, 95% CI: 0.812-0.968, P=0.007). Although the 95% CIs of MR Egger, Weighted median, Simple mode, and Weighted mode were broad, the majority of their estimates were consistent with the direction of IVW. Despite significant heterogeneity among SNPs, no horizontal pleiotropy was observed. The leave-one-out analysis showed that the causality remained consistent after each SNP was removed, underscoring the reliability of the results. Reverse MR analysis indicated that genetic susceptibility to both CRC and IBD had no significant effect on the relative risk of T2DM. Ten hub genes were identified, which mainly enriched in pathways including maturity onset diabetes of the young, thyroid cancer, gastric acid secretion, longevity regulating pathway, melanogenesis, and pancreatic secretion.

Conclusion

The presence of T2DM does not increase the risk of CRC or IBD. Moreover, T2DM might reduce risk of IBD, including UC. Conversely, the occurrence of CRC or IBD does not influence the risk of T2DM. The association between T2DM and IBD/UC may be related to the changes in multiple metabolic pathways and CTLA-4-mediated immune response.

Saccharomyces boulardii promoters for control of gene expression in vivo

BACKGROUND

Interest in the use of engineered microbes to deliver therapeutic activities has increased in recent years. The probiotic yeast Saccharomyces boulardii has been investigated for production of therapeutics in the gastrointestinal tract. Well-characterised promoters are a prerequisite for robust therapeutic expression in the gut; however, S. boulardii promoters have not yet been thoroughly characterised in vitro and in vivo.

RESULTS

We present a thorough characterisation of the expression activities of 12 S. boulardii promoters in vitro in glucose, fructose, sucrose, inulin and acetate, under both aerobic and anaerobic conditions, as well as in the murine gastrointestinal tract. Green fluorescent protein was used to report on promoter activity. Promoter expression was found to be carbon-source dependent, with inulin emerging as a favourable carbon source. Furthermore, relative promoter expression in vivo was highly correlated with expression in sucrose (R = 0.99).

CONCLUSIONS

These findings provide insights into S. boulardii promoter activity and aid in promoter selection in future studies utilising S. boulardii to produce therapeutics in the gut.

Paracrine signalling by pancreatic δ cells determines the glycaemic set point in mice

While pancreatic β and α cells are considered the main drivers of blood glucose homeostasis through insulin and glucagon secretion, the contribution of δ cells and somatostatin (SST) secretion to glucose homeostasis remains unresolved. Here we provide a quantitative assessment of the physiological contribution of δ cells to the glycaemic set point in mice. Employing three orthogonal mouse models to remove SST signalling within the pancreas or transplanted islets, we demonstrate that ablating δ cells or SST leads to a sustained decrease in the glycaemic set point. This reduction coincides with a decreased glucose threshold for insulin response from β cells, leading to increased insulin secretion to the same glucose challenge. Our data demonstrate that β cells are sufficient to maintain stable glycaemia and reveal that the physiological role of δ cells is to provide tonic feedback inhibition that reduces the β cell glucose threshold and consequently lowers the glycaemic set point in vivo.

Detection of Meals and Physical Activity Events From Free-Living Data of People With Diabetes

BACKGROUND

Predicting carbohydrate intake and physical activity in people with diabetes is crucial for improving blood glucose concentration regulation. Patterns of individual behavior can be detected from historical free-living data to predict meal and exercise times. Data collected in free-living may have missing values and forgotten manual entries. While machine learning (ML) can capture meal and exercise times, missing values, noise, and errors in data can reduce the accuracy of ML algorithms.

METHODS

Two recurrent neural networks (RNNs) are developed with original and imputed data sets to assess detection accuracy of meal and exercise events. Continuous glucose monitoring (CGM) data, insulin infused from pump data, and manual meal and exercise entries from free-living data are used to predict meals, exercise, and their concurrent occurrence. They contain missing values of various lengths in time, noise, and outliers.

RESULTS

The accuracy of RNN models range from 89.9% to 95.7% for identifying the state of event (meal, exercise, both, or neither) for various users. "No meal or exercise" state is determined with 94.58% accuracy by using the best RNN (long short-term memory [LSTM] with 1D Convolution). Detection accuracy with this RNN is 98.05% for meals, 93.42% for exercise, and 55.56% for concurrent meal-exercise events.

CONCLUSIONS

The meal and exercise times detected by the RNN models can be used to warn people for entering meal and exercise information to hybrid closed-loop automated insulin delivery systems. Reliable accuracy for event detection necessitates powerful ML and large data sets. The use of additional sensors and algorithms for detecting these events and their characteristics provides a more accurate alternative.

Diabetic Gastroparesis and its Emerging Therapeutic Options: A Narrative Review of the Literature

Diabetic gastroparesis (DG) is one of the many complications of diabetes mellitus (DM). Even though this condition surfaces years after uncontrolled disease, it affects the quality of life in several ways and causes significant morbidity. Common symptoms experienced by the patients include postprandial nausea, vomiting, abdominal fullness, and pain. Strict glycemic control is essential to evade the effects of DG. The purpose of this review article is to briefly study the pathophysiology, clinical features, diagnostic modalities, and the effects of DG on different aspects of life. Furthermore, it also focuses on the emerging treatment modalities for DG. Tradipitant and relamorelin are two such treatment options that are gaining noteworthy recognition and are discussed in detail in this review article. As observed through various clinical trials, these drugs help alleviate symptoms like nausea, vomiting, abdominal pain, and bloating in patients suffering from DG, thereby targeting the most common and bothersome symptoms of the disease. This leads to an improvement in the quality of life, making it a reliable treatment option for this disease. But while pharmacological intervention is vital, psychological support and lifestyle changes are equally important and are the reason why a multidisciplinary approach is required for the treatment of DG.

The role of gastric emptying in glucose homeostasis and defense against hypoglycemia: Innocent bystander or partner in crime?

Maintenance of plasma glucose (PG) homeostasis is due to a complex network system. Even a minor fall in PG activates multiple neuroendocrine actions promoting hormonal, metabolic and behavioral responses, which prevent and ultimately recover hypoglycemia, primarily neuroglycopenia. Among these responses, gastric emptying (GE) plays an important role by coordinated mechanisms which regulate transit and absorption of nutrients through the small intestine. A bidirectional relationship between GE and glycemia has been established: GE may explain the up to 30-40 % variance in glycemic response following a carbohydrate-rich meal. In addition, acute and chronic hyperglycemia induce deceleration of GE after meals. Hypoglycemia accelerates GE, but its role in counterregulation has been poorly investigated. The role of GE as a counterregulatory mechanism has been confirmed in pathophysiological conditions, such as gastroparesis or following recurrent hypoglycemia. Therefore, it could represent an "ancestral" mechanism, highly conservative and effective in all individuals, conditions and clinical contexts. Recent guidelines recommend GLP-1 receptor agonists (GLP-1RAs) either as the first injectable therapy for type 2 diabetes mellitus or in combination with insulin. Considering the potential impact on GE, it would be important to study subjects on GLP-1 RAs during hypoglycemia, to establish whether a possible deceleration of GE impairs glucose counterregulation.

Effect of Bitter-leaf (Vernonia amygdalina) Flavored Non-alcoholic Wheat Beer (NAWB) on, Insulin and GLUT-2 expression in Pancreas of High fat diet/Streptozotocin (HFD/STZ) Induced Diabetic Wistar Rats

Purpose

In the management of type 2 diabetes (T2D), dietary intervention has been proposed to be highly effective. This study, therefore, investigated the effect of bitter leaf-flavored non-alcoholic wheat beer (NAWB) on insulin secretion and GLUT-2 expression in the pancreas of STZ-induced diabetic rats.

Methods

In this study, the rats received a single intraperitoneal injection (i.p.) of STZ (35 mg/kg) after being fed a high-fat diet for 14 days to induce T2D. The rats were treated with bitter leaf flavored NAWB samples (100%HP- Hops only, 100%BL-Bitter leaf only, 75,25BL- 75% Hops, 25% Bitter Leaf, 50:50BL- 50% Hops:50% Bitter Leaf, and 25:75BL-25%Hops:75% Bitter Leaf) and Acarbose for 14 days. The superoxide dismutase, catalase, and glutathione peroxidase activity were also determined.

Results

The results from this study showed a correlation between GLUT-2 and Insulin expression. There was an upregulation of Insulin as GLUT-2 expression was upregulated. Furthermore, the treated groups showed better antioxidant activity when compared with the diabetic control.

Conclusion

Bitter leaf-flavored NAWB might thus be a good dietary intervention for type 2 diabetics.

Estimation of glucose rate of appearance in portal vein circulation using a phenomenological-based model

The joint work of the stomach and the small intestine plays a fundamental role in human digestion. In the stomach, food is turned into a semi-fluid mixture that is slowly released into the small intestine, where most enzymatic reactions occur, and nutrients are absorbed as they become available. This whole process is closely related to glucose homeostasis, mainly because of the appearance of glucose in the portal system and the energetic expenditure of the process itself. The current phenomenological-based model describes such effects of the digestive process on blood glucose concentration. It considers enzymatic and mechanical transformations, energetic expenditure, and the impact of macro-nutrients, fiber, and water on overall digestion and glucose absorption. The model estimates the rate of glucose appearance in the portal vein and is intended to be further integrated into existing models for other human organs and used in model-based systems such as an artificial pancreas with automated insulin delivery.

Famsin, a novel gut-secreted hormone, contributes to metabolic adaptations to fasting via binding to its receptor OLFR796

The intestine is responsible for nutrient absorption and orchestrates metabolism in different organs during feeding, a process which is partly controlled by intestine-derived hormones. However, it is unclear whether the intestine plays an important role in metabolism during fasting. Here we have identified a novel hormone, famsin, which is secreted from the intestine and promotes metabolic adaptations to fasting. Mechanistically, famsin is shed from a single-pass transmembrane protein, Gm11437, during fasting and then binds OLFR796, an olfactory receptor, to activate intracellular calcium mobilization. This famsin-OLFR796 signaling axis promotes gluconeogenesis and ketogenesis for energy mobilization, and torpor for energy conservation during fasting. In addition, neutralization of famsin by an antibody improves blood glucose profiles in diabetic models, which identifies famsin as a potential therapeutic target for treating diabetes. Therefore, our results demonstrate that communication between the intestine and other organs by a famsin-OLFR796 signaling axis is critical for metabolic adaptations to fasting.

Current Updates in Rectal Infusion of Fluids and Medications

Purpose of Review

Rectal infusion is a feasible alternative for the immediate administration of medication and fluids when intravenous access is delayed, contraindicated, or unnecessary. Advances in medical device technology have made rectal infusion more practical and easier for medical care providers, and more comfortable for patients. This paper briefly reviews the history of therapeutic rectal infusion, including recent improvements in technology and the existing evidence for the use of this technique.

Recent Findings

While ultrasound-guided peripheral intravenous (PIV) access techniques and other alternatives to landmark-based PIV catheter insertion have recently improved the ability of providers to overcome challenges related to difficult vascular access (DVA), these challenges are increasingly affecting patient outcomes, emergency department throughput, and the cost of medical care. In recent years, waves of parenteral drug, fluid, and supply shortages have affected hospitals. Concurrently, advances in rectal infusion technology have made rectal infusion easier, more comfortable, and more cost-effective than many parenteral options.

Summary

The infusion of resuscitative fluids and medications via the rectal route has previously fallen out of favor due to concurrent improvements in IV access devices. However, this technique demonstrates the potential for a reemergence considering the current challenges facing healthcare providers and systems. Improvements in rectal infusion devices, coupled with an aging population, increased incidence of DVA, shortages in parenteral drugs, fluids, supplies and skilled staff, and the need for care improvements in the post-acute setting have contributed to a greater need for easy, safe and effective alternatives to IV infusion.

Inhibitory Potential of α-Amylase, α-Glucosidase, and Pancreatic Lipase by a Formulation of Five Plant Extracts: TOTUM-63

Controlling post-prandial hyperglycemia and hyperlipidemia, particularly by regulating the activity of digestive enzymes, allows managing type 2 diabetes and obesity. The aim of this study was to assess the effects of TOTUM-63, a formulation of five plant extracts (Olea europaea L., Cynara scolymus L., Chrysanthellum indicum subsp. afroamericanum B.L.Turner, Vaccinium myrtillus L., and Piper nigrum L.), on enzymes involved in carbohydrate and lipid absorption. First, in vitro inhibition assays were performed by targeting three enzymes: α-glucosidase, α-amylase, and lipase. Then, kinetic studies and binding affinity determinations by fluorescence spectrum changes and microscale thermophoresis were performed. The in vitro assays showed that TOTUM-63 inhibited all three digestive enzymes, particularly α-glucosidase (IC50 of 13.1 µg/mL). Mechanistic studies on α-glucosidase inhibition by TOTUM-63 and molecular interaction experiments indicated a mixed (full) inhibition mechanism, and higher affinity for α-glucosidase than acarbose, the reference α-glucosidase inhibitor. Lastly, in vivo data using leptin receptor-deficient (db/db) mice, a model of obesity and type 2 diabetes, indicated that TOTUM-63 might prevent the increase in fasting glycemia and glycated hemoglobin (HbA1c) levels over time, compared with the untreated group. These results show that TOTUM-63 is a promising new approach for type 2 diabetes management via α-glucosidase inhibition.

Naringenin modulates Cobalt activities on gut motility through mechanosensors and serotonin signalling

IntroductionCobalt chloride-(CoCl₂) exerts beneficial and toxic activities depending on dose however Naringenin-(Nar) a flavonoid, chelates heavy metals. Absorption of ingested heavy metals, or chelates are dependent on gut motility (gastric emptying and intestinal transit time) and mechanosensor regulation. Literature is vague on CoCl₂ activities on gut motility and mechanosensor nor probable chelating actions with naringenin which was investigated in this study.MethodOne hundred male Wistar rats were grouped viz; A to D (25, 62, 150 and 300 mg/kg CoCl₂), E to H doses of CoCl₂+Nar (50 mg/kg), I-Narigenin and J-Control. Gastric emptying and intestinal transit time were evaluated by day eight, intestinal tissue assayed for biochemical, histological and immunohistochemistry reactivity.ResultCoCl₂ significantly increased Gastric emptying (150 and 300 mg/kg) and Intestinal transit time unlike Naringenin. CoCl₂ (150 mg/kg) significantly increased Catalase and Nitric oxide but ameliorated by Naringenin. ATPase activities significantly increased in 150 mg/kg-CoCl₂ but ameliorated by Naringenin. Carbonyl levels increased in all CoCl₂+Nar groups. High Enterochromaffin-cell count in 25 and 62 mg/kg-CoCl₂ were ameliorated by Naringenin. Serotonin immunoreactivity increased in CoCl₂ (25, 62, 300 mg/kg) but reduced in CoCl₂+Nar groups.ConclusionCobalt chloride enhanced gastric motility via increased mechanosensor activities and serotonin expression at low doses. Naringenin ameliorated toxicity of high cobalt chloride via metal-flavonoid chelates.

Effects of overfeeding on the digestive efficiency, voluntary physical activity levels, and fecal characteristics and microbiota of adult cats

The incidence of feline obesity continues to rise despite it being a preventable disease. There are many risks and health perturbations associated with obesity, with several of those impacting a pet's quality of life, wellness, and longevity. Feline obesity is commonly studied, but most research has been focused on weight loss rather than weight gain. To our knowledge, feline studies have not examined the implications of overfeeding and weight gain on gastrointestinal transit time (GTT) nor the association it has with the fecal microbiota. Therefore, the objective of this study was to determine the effects of overfeeding and weight gain on apparent total tract digestibility (ATTD), GTT, blood hormones, serum metabolites, hematology, fecal microbiota populations, and voluntary physical activity of cats. Eleven lean adult spayed female cats [body weight (BW) = 4.11 ± 0.43 kg; body condition score = 5.41 ± 0.3; age = 5.22 ± 0.03 y] were used in a longitudinal weight gain study. After a 2-wk baseline phase, cats were allowed to overeat for 18 wk. A commercially available complete and balanced diet was fed during the baseline phase to identify the intake needed to maintain BW. Cats were then fed the same diet ad libitum to induce weight gain. Fecal samples, blood samples, and voluntary physical activity data were collected at baseline (week 0) and 6, 12, and 18 wk after weight gain. Fecal samples were collected for microbiota analysis, determination of ATTD, and GTT measurement while blood samples were collected for serum chemistry, hematology, and insulin and leptin measurements. Microbiota data were evaluated using QIIME2. All other measures were evaluated statistically using the mixed models procedure of SAS using repeated measures analysis, with time effects being the focus. A P < 0.05 was considered significant. The ATTD of dry matter (P = 0.0061), organic matter (P = 0.0130), crude protein (P < 0.0001), fat (P = 0.0002), and gross energy (P = 0.0002), and GTT (P = 0.0418) decreased with overfeeding and weight gain. Fecal bacterial alpha diversity measures were unchanged, but fecal bacterial beta diversity was impacted (P < 0.05) with overfeeding and weight gain. The relative abundances of 16 bacterial genera, including Bifidobacterium, Collinsella, Erysipelatoclostridium were affected (P < 0.05) by overfeeding and weight gain. In conclusion, overfeeding and subsequent weight gain reduced ATTD, reduced GTT, and caused changes to the fecal microbial community of adult cats.

Glucose supplementation improves intestinal amino acid transport and muscle amino acid pool in pigs during chronic cold exposure

Mammals in northern regions chronically suffer from low temperatures during autumn-winter seasons. The aim of this study was to investigate the response of intestinal amino acid transport and the amino acid pool in muscle to chronic cold exposure via Min pig models (cold adaptation) and Yorkshire pig models (non-cold adaptation). Furthermore, this study explored the beneficial effects of glucose supplementation on small intestinal amino acid transport and amino acid pool in muscle of cold-exposed Yorkshire pigs. Min pigs (Exp. 1) and Yorkshire pigs (Exp. 2) were divided into a control group (17 °C, n = 6) and chronic cold exposure group (7 °C, n = 6), respectively. Twelve Yorkshire pigs (Exp. 3) were divided into a cold control group and cold glucose supplementation group (8 °C). The results showed that chronic cold exposure inhibited peptide transporter protein 1 (PepT1) and excitatory amino acid transporter 3 (EAAT3) expression in ileal mucosa and cationic amino acid transporter-1 (CAT-1) in the jejunal mucosa of Yorkshire pigs (P < 0.05). In contrast, CAT-1, PepT1 and EAAT3 expression was enhanced in the duodenal mucosa of Min pigs (P < 0.05). Branched amino acids (BCAA) in the muscle of Yorkshire pigs were consumed by chronic cold exposure, accompanied by increased muscle RING-finger protein-1 (MuRF1) and muscle atrophy F-box (atrogin-1) expression (P < 0.05). More importantly, reduced concentrations of dystrophin were detected in the muscle of Yorkshire pigs (P < 0.05). However, glycine concentration in the muscle of Min pigs was raised (P < 0.05). In the absence of interaction between chronic cold exposure and glucose supplementation, glucose supplementation improved CAT-1 expression in the jejunal mucosa and PepT1 expression in the ileal mucosa of cold-exposed Yorkshire pigs (P < 0.05). It also improved BCAA and inhibited MuRF1 and atrogin-1 expression in muscle (P < 0.05). Moreover, dystrophin concentration was improved by glucose supplementation (P < 0.05). In summary, chronic cold exposure inhibits amino acid absorption in the small intestine, depletes BCAA and promotes protein degradation in muscle. Glucose supplementation ameliorates the negative effects of chronic cold exposure on amino acid transport and the amino acid pool in muscle.

Effects of Carbohydrate and Fats in Turkish Patients with Type 2 Diabetes

Aim: This study aimed to assess the effects of different kinds of diet, which were similar in total energy density but different in carbohydrate and fats, on some blood parameters in type 2 diabetics. Materials and Methods: In this study, 33 type 2 diabetics, participants were offered two different kinds of lunches within 7 days intervals. Venous blood samples were collected from the participants half an hour before and after the consumption of these meals (0-180 minutes). Blood parameters such as glucose, insulin, low-density lipoprotein (LDL-C), high-density lipoprotein (HDL-C), and triglyceride were analyzed through blood samples. Results: There was no significance between the values of the change in blood glucose before and after their consumption of the standard meal and etli ekmek. After the consumption of the etli ekmek difference between the participants’ mean insulin level values at 60 and 90 minutes was lower than the standard meal. The values under the curve (AUC) were found to be significant (p

A Gut-Centric Model of Metabolic Homeostasis

Modern changes in diet and lifestyle have led to an explosion of insulin resistance and metabolic diseases around the globe which, if left unchecked, will become a principal driver of morbidity and mortality in the 21st century. The nature of the metabolic homeostatic shift within the body has therefore become a topic of considerable interest. While the gut has long been recognized as an acute nutrient sensor with signaling mechanisms to the other metabolic organs of the body, its role in regulating the body's metabolic status over longer periods of time has been underappreciated. Recent insights from bariatric surgery and intestinal nutrient stimulation experiments provide a window into the adaptive role of the intestinal mucosa in a foregut/hindgut metabolic balance model that helps to define metabolic parameters within the body-informing the metabolic regulation of insulin resistance versus sensitivity, hunger versus satiety, energy utilization versus energy storage, and protection from hypoglycemia versus protection from hyperglycemia. This intestinal metabolic balance model provides an intellectual framework with which to understand the distinct roles of proximal and distal intestinal segments in metabolic regulation. The model may also aid in the development of novel disease-modifying therapies that can correct the dysregulated metabolic signals from the intestine and stem the tide of metabolic diseases in society.

The characteristics of postprandial glycemic response patterns to white rice and glucose in healthy adults: Identifying subgroups by clustering analysis

OBJECTIVES

Large interpersonal variability in postprandial glycemic response (PGR) to white rice has been reported, and differences in the PGR patterns during the oral glucose tolerance test (OGTT) have been documented. However, there is scant study on the PGR patterns of white rice. We examined the typical PGR patterns of white rice and glucose and the association between them.

MATERIALS AND METHODS

We analyzed the data of 3-h PGRs to white rice (WR) and glucose (G) of 114 normoglycemic female subjects of similar age, weight status, and same ethnic group. Diverse glycemic parameters, based on the discrete blood glucose values, were calculated over 120 and 180 min. K-means clustering based on glycemic parameters calculated over 180 min was applied to identify subgroups and representative PGR patterns. Principal factor analysis based on the parameters used in the cluster analysis was applied to characterize PGR patterns. Simple correspondence analysis was performed on the clustering categories of WR and G.

RESULTS

More distinct differences were found in glycemic parameters calculated over 180 min compared with that calculated over 120 min, especially in the negative area under the curve and Nadir. We identified four distinct PGR patterns to WR (WR1, WR2, WR3, and WR4) and G (G1, G2, G3, and G4), respectively. There were significant differences among the patterns regard to postprandial hyperglycemia, hypoglycemic, and glycemic variability. The WR1 clusters had significantly lower glycemic index (59 ± 19), while no difference was found among the glycemic index based on the other three clusters. Each given G subgroup presented multiple patterns of PGR to WR, especially in the largest G subgroup (G1), and in subgroup with the greatest glycemic variability (G3).

CONCLUSION

Multiple subgroups could be classified based on the PGR patterns to white rice and glucose even in seemingly homogeneous subjects. Extending the monitoring time to 180 min was conducive to more effective discrimination of PGR patterns. It may not be reliable to extrapolate the patterns of PGR to rice from that to glucose, suggesting a need of combining OGTT and meal tolerance test for individualized glycemic management.

The glucagon receptor antagonist LY2409021 does not affect gastrointestinal-mediated glucose disposal or the incretin effect in individuals with and without type 2 diabetes

OBJECTIVE

Gastrointestinal-mediated glucose disposal (GIGD) during oral glucose tolerance test (OGTT) reflects the percentage of glucose disposal caused by mechanisms elicited by the oral route of glucose administration. GIGD is reduced in patients with type 2 diabetes (T2D) due to a reduced incretin effect and possibly also due to inappropriate suppression of glucagon after oral glucose. We investigated the effect of glucagon receptor antagonism on GIGD, the incretin effect and glucose excursions in patients with T2D and controls without diabetes.

DESIGN

A double-blind, randomised, placebo-controlled crossover study was conducted.

METHODS

Ten patients with T2D and 10 gender-, age- and BMI-matched controls underwent two 50 g OGTTs and 2 isoglycaemic i.v. glucose infusions, succeeding (~10 h) single-dose administration of 100 mg of the glucagon receptor antagonist LY2409021 or placebo, respectively.

RESULTS

Compared to placebo, LY2409021 reduced fasting plasma glucose in patients with T2D and controls. Plasma glucose excursions after oral glucose assessed by baseline-subtracted area under the curve were increased by LY2409021 compared to placebo in both groups, but no effect of LY2409021 on GIGD or the incretin effect was observed. LY2409021 increased fasting glucagon concentrations three-fold compared to placebo concentrations.

CONCLUSIONS

Glucagon receptor antagonism with LY2409021 had no effect on the impaired GIGD or the impaired incretin effect in patients with T2D and did also not affect these parameters in the controls. Surprisingly, we observed reduced oral glucose tolerance with LY2409021 which may be specific for this glucagon receptor antagonist.

Metabolic effects of truncal vagotomy when combined with bariatric-metabolic surgery

Bariatric-metabolic surgery (BMS) in patients with obesity frequently leads to remission of concurrent type 2 diabetes mellitus (T2DM), even before body weight loss takes place. This is probably based on the correction of a dysmetabolic cycle in the gastrointestinal physiology of T2DM that includes increased vagus-dependent exocrine pancreatic secretion (EPS) and, hence, amplified digestion and nutrient absorption. The resultant chronic exposure of tissues to high plasma levels of glucose, fatty acids and amino acids causes tissue resistance to the actions of insulin and, at a later stage, β-cell dysfunction and reduction of insulin release. We hypothesize that the addition of a surgical truncal vagotomy (TV) may improve and solidify the beneficial results of BMS on T2DM by stably decreasing EPS, - hence reducing the digestion and absorption of nutrients -, and increasing incretin secretion as a result of increased delivery of unabsorbed nutrients to the distal intestine. This hypothesis is supported by surgical data from gastrointestinal malignancies and peptic ulcer operations that include TV, as well as by vagal blockade studies. We suggest that TV may result in a stable reduction of EPS, and that its combination with the appropriate type of BΜS, may enhance and sustain the salutary effects of the latter on T2DM.

Current and future approaches for in vitro hit discovery in diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a serious public health problem. In this review, we discuss current and promising future drugs, targets, in vitro assays and emerging omics technologies in T2DM. Importantly, we open the perspective to image-based high-content screening (HCS), with the focus of combining it with metabolomics or lipidomics. HCS has become a strong technology in phenotypic screens because it allows comprehensive screening for the cell-modulatory activity of small molecules. Metabolomics and lipidomics screen for perturbations at the molecular level. The combination of these data-intensive comprehensive technologies is enabled by the rapid development of artificial intelligence. It promises a deep cellular and molecular phenotyping directly linked to chemical information about the applied drug candidates or complex mixtures.

A glucose-insulin-glucagon coupled model of the isoglycemic intravenous glucose infusion experiment

Type 2 diabetes (T2D) is a pathophysiology that is characterized by insulin resistance, beta- and alpha-cell dysfunction. Mathematical models of various glucose challenge experiments have been developed to quantify the contribution of insulin and beta-cell dysfunction to the pathophysiology of T2D. There is a need for effective extended models that also capture the impact of alpha-cell dysregulation on T2D. In this paper a delay differential equation-based model is developed to describe the coupled glucose-insulin-glucagon dynamics in the isoglycemic intravenous glucose infusion (IIGI) experiment. As the glucose profile in IIGI is tailored to match that of a corresponding oral glucose tolerance test (OGTT), it provides a perfect method for studying hormone responses that are in the normal physiological domain and without the confounding effect of incretins and other gut mediated factors. The model was fit to IIGI data from individuals with and without T2D. Parameters related to glucagon action, suppression, and secretion as well as measures of insulin sensitivity, and glucose stimulated response were determined simultaneously. Significant impairment in glucose dependent glucagon suppression was observed in patients with T2D (duration of T2D: 8 (6–36) months) relative to weight matched control subjects (CS) without diabetes (k1 (mM)−1: 0.16 ± 0.015 (T2D, n = 7); 0.26 ± 0.047 (CS, n = 7)). Insulin action was significantly lower in patients with T2D (a1 (10 pM min)−1: 0.000084 ± 0.0000075 (T2D); 0.00052 ± 0.00015 (CS)) and the Hill coefficient in the equation for glucose dependent insulin response was found to be significantly different in T2D patients relative to CS (h: 1.4 ± 0.15; 1.9 ± 0.14). Trends in parameters with respect to fasting plasma glucose, HbA1c and 2-h glucose values are also presented. Significantly, a negative linear relationship is observed between the glucagon suppression parameter, k1, and the three markers for diabetes and is thus indicative of the role of glucagon in exacerbating the pathophysiology of diabetes (Spearman Rank Correlation: (n = 12; (−0.79, 0.002), (−0.73,.007), (−0.86,.0003)) respectively).

Sugars and Gastrointestinal Health

Sugar overconsumption is linked to a rise in the incidence of noncommunicable diseases such as diabetes, cardiovascular diseases, and cancer. This increased incidence is becoming a real public health problem that is more severe than infectious diseases, contributing to 35 million deaths annually. Excessive intake of free sugars can cause many of the same health problems as excessive alcohol consumption. Many recent international recommendations have expressed concerns about sugar consumption in Westernized societies, as current consumption levels represent quantities with no precedent during hominin evolution. In both adults and children, the World Health Organization strongly recommends reducing free sugar intake to <10% of total energy intake and suggests a further reduction to below 5%. Most studies have focused on the deleterious effects of Western dietary patterns on global health and the intestine. Whereas excessive dietary fat consumption is well studied, the specific impact of sugar is poorly described, while refined sugars represent up to 40% of caloric intake within industrialized countries. However, high sugar intake is associated with multiple tissue and organ dysfunctions. Both hyperglycemia and excessive sugar intake disrupt the intestinal barrier, thus increasing gut permeability and causing profound gut microbiota dysbiosis, which results in a disturbance in mucosal immunity that enhances infection susceptibility. This review aims to highlight the roles of different types of dietary carbohydrates and the consequences of their excessive intake for intestinal homeostasis.

Antihyperglycemic and antihyperlipidemic activities of hydroethanolic extract of the fruit of Baillonella toxisperma in streptozotocin-induced diabetic rats

Objective

This work evaluated the antihyperglycemic and antihyperlipidemic activities of pulp extracts of B. toxisperma fruits in rats.

Methods

The regulatory ability of the extract on the secretory capacity of pancreatic beta cells (oral glucose tolerance test), and digestion and/or absorption of carbohydrates (starch and sucrose) were evaluated on normal Wistar rats. Diabetes was induced in Wistar rats by intravenous administration of streptozotocin (50 mg/kg), and the animals were treated by the administration of a single daily dose of 400 mg/kg BW of extract. The effect of the extract on blood glucose levels of diabetic rats was monitored 30 min, 2 h, and 5 h after administration, and on the 7th and 14th days of treatment. After 2 weeks of treatment, the rats were sacrificed, liver was preserved for the determination of glycogen content. The serum was prepared and markers for nephro and hepatotoxicity were assessed, as well as cardiovascular risk.

Results

The hydroethanolic extract of B. toxisperma fruits significantly reduced glucose concentrations after administration of starch and sucrose in normoglycemic rats by limiting the glycemic peak (increasing of 19.67% vs 27.88% for positive control and 35.96% vs 43.97% for positive control, for starch and sucrose respectively). No effect was observed after glucose administration. B. toxisperma fruits significantly decreased glucose levels by 14.5% and 54.23% respectively 30 min after administration and 7th days of treatment respectively. The extract decreased plasma triglycerides and total cholesterol levels in diabetic rats; it also decreased the cardiovascular risk through the reduction of Cardiac Risk Ratio, Atherogenic Coefficient, and non-High-Density Lipoprotein Cholesterol. The extract also promoted renal function but not structural integrity of the liver.

Conclusions

This study suggests that the hydroethanolic pulp extracts of B. toxisperma fruits are good antihyperglycemic and antihyperlipidemic properties agents and could be a potential source of compounds for diabetes management.

Intestinal mucus-derived metabolites modulate virulence of a clade 8 enterohemorrhagic Escherichia coli O157:H7

The human colonic mucus is mainly composed of mucins, which are highly glycosylated proteins. The normal commensal colonic microbiota has mucolytic activity and is capable of releasing the monosaccharides contained in mucins, which can then be used as carbon sources by pathogens such as Enterohemorrhagic Escherichia coli (EHEC). EHEC can regulate the expression of some of its virulence factors through environmental sensing of mucus-derived sugars, but its implications regarding its main virulence factor, Shiga toxin type 2 (Stx2), among others, remain unknown. In the present work, we have studied the effects of five of the most abundant mucolytic activity-derived sugars, Fucose (L-Fucose), Galactose (D-Galactose), N-Gal (N-acetyl-galactosamine), NANA (N-Acetyl-Neuraminic Acid) and NAG (N-Acetyl-D-Glucosamine) on EHEC growth, adhesion to epithelial colonic cells (HCT-8), and Stx2 production and translocation across a polarized HCT-8 monolayer. We found that bacterial growth was maximum when using NAG and NANA compared to Galactose, Fucose or N-Gal, and that EHEC adhesion was inhibited regardless of the metabolite used. On the other hand, Stx2 production was enhanced when using NAG and inhibited with the rest of the metabolites, whilst Stx2 translocation was only enhanced when using NANA, and this increase occurred only through the transcellular route. Overall, this study provides insights on the influence of the commensal microbiota on the pathogenicity of E. coli O157:H7, helping to identify favorable intestinal environments for the development of severe disease.

Exendin-4 inhibits small intestinal glucose sensing and absorption through repression of T1R2/T1R3 sweet taste receptor signalling in streptozotocin diabetic mice

The small intestine, which is the area where sugars are absorbed, should be considered in the approaches developed for the treatment of diabetes. However, studies on small intestine damage in diabetic individuals, and the effects of current treatments on the small intestine are very limited. This is the first study to investigate the effects of exendin-4, a GLP-1 receptor agonist, on small intestine injury in diabetic mice. BALB/c male mice were divided into 4 groups for this study. The first group was given citrate buffer, the second group was given exendin-4, the third group was given streptozotocin (STZ), and the fourth group was given both exendin-4, and STZ. As the results, we determined a decrease in the edema and deterioration in the integrity of the villi, disruption in continuity of the brush border, fibrosis and enterocyte apoptosis, while the TNFα level and crypt cell proliferation were increased in the small intestinal tissue of exendin-4 treated STZ diabetic mice. Furthermore, the levels of duodenal tissue glucose, SGLT1, and GLUT2 were decreased, whereas there was an increase in GIP level in diabetic mice administered with exendin-4. Moreover, we determined that the sweet taste receptors T1R2/T1R3, downstream molecules PLCβ2, α-gustducin and associated secondary messengers IP3, cAMP, which were increased in the duodenal tissue of STZ-diabetic mice, decreased with exendin-4 administration. These findings were evaluated as that exendin-4 reduces glucose absorption by suppressing the T1R2/T1R3 sweet taste signal perception pathway in duodenum of STZ diabetic mice.

Glucose Reduces Norovirus Binding to Enterobacter cloacae and Alters Gene Expression of Bacterial Surface Structures in a Growth Phase Dependent Manner

Norovirus is the leading cause of acute viral gastroenteritis. Both human and murine noroviruses attach to commensal bacteria belonging to the mammalian gut flora, and binding levels are influenced by nutrients present in bacterial media. However, it is not known which nutrients are responsible for altering viral binding or why binding is altered. Gene expression of commensal bacteria can be changed by the external environment as well as by interaction with pathogens. For example, growth phase and incubation conditions impact expression levels of specific bacterial genes in Escherichia coli. We have previously shown that binding by both human and murine noroviruses to the commensal bacterium Enterobacter cloacae induces genome-wide changes in gene expression with a large number of differentially expressed genes associated with the surface structure of the bacterial cell. The current study evaluated norovirus binding under nutrient-limited conditions and assessed the expression of a select panel of these genes that are significantly altered by norovirus binding under these conditions. The goal of this work was to determine how norovirus attachment to Enterobacter cloacae affected the expression of these genes under varying nutrient and growth phase conditions. We found that the presence of glucose in minimal media reduced murine norovirus binding to E. cloacae and viral binding in the presence of glucose reduced gene expression for surface structures previously associated with norovirus attachment. Changes in viral binding and gene expression occurred in a growth phase-dependent manner. Collectively, these data demonstrate that both the growth phase and nutrient availability alter viral interactions with commensal bacteria and the subsequent changes in gene expression. Ultimately, this work advances our understanding of norovirus-bacterium interactions and provides a foundation for elucidating the conditions and surface structures that regulate norovirus attachment to bacteria.

Dietary Glucose Ameliorates Impaired Intestinal Development and Immune Homeostasis Disorders Induced by Chronic Cold Stress in Pig Model

Endotherms are easily challenged by chronic cold stress. In this study, the development and injury of the small intestine in the Min pig model and Yorkshire pig model under chronic cold stress, and the molecular mechanisms by which glucose supplementation reduces small intestinal mucosal damage were investigated. The results showed that morphological structure lesions of the jejunal mucosa and ileal mucosa were visible in Yorkshire pigs under chronic cold stress. Meanwhile, the Occludin mRNA and protein expression in jejunal mucosa of Yorkshire pigs was decreased. Chronic cold stress enhanced the expression of Toll-like receptor 4 (TLR4), the myeloid differentiation main response 88 (MyD88), nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3), cleaved caspase-1, mature-IL-1β, and high-mobility group box 1 (HMGB 1) mRNA and protein expression in jejunal mucosa of Yorkshire pigs, whereas the mRNA and protein of Bax was triggered in ileal mucosa. In Min pigs, no such deleterious consequences were observed. Dietary glucose supplementation ameliorates small intestinal mucosal injury, declined TLR4 and MyD88 expression in jejunal mucosa. In conclusion, chronic cold stress induced the small intestinal mucosa damage in Yorkshire pigs, whereas glucose supplementation mitigated the deleterious effects of chronic cold stress on the small intestine.

A Pilot Study to Assess Glucose, Insulin, and Incretin Responses Following Novel High Resistant Starch Rice Ingestion in Healthy Men

INTRODUCTION

A newly developed resistant starch (RS) rice line with double mutation of starch synthase IIIa and branching enzyme IIb (ss3a/be2b) exhibits a tenfold greater percentage RS value than the wild-type rice line. Currently, the effects of cooked rice with such high RS content on secretion and action of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are unclear. Therefore, we conducted a pilot study to assess postprandial responses of GLP-1 and GIP along with glucose and insulin and also gastric emptying after ingestion of the high-RS cooked rice with ss3a/be2b in healthy subjects.

METHODS

In a non-randomized crossover design, five healthy men ingested two test foods, control (low-RS) and high-RS cooked rice, with at least 1-week washout period between testing days. Plasma glucose, serum insulin, plasma total GLP-1, plasma total GIP, and also gastric emptying rate were measured after ingestion of each test food, and the incremental area under the curves (iAUC) was calculated for each biochemical parameter using the values from 0 to 180 min after ingestion.

RESULTS

The high-RS cooked rice ingestion tended to reduce iAUC-glucose (p = 0.06) and significantly reduced iAUC-insulin (p < 0.01) and iAUC-GLP-1 (p < 0.05) but not iAUC-GIP (p = 0.21) relative to control cooked rice ingestion. In addition, the high-RS cooked rice ingestion did not affect gastric emptying.

CONCLUSIONS

The present results indicate that the suppressive effects of the high-RS cooked rice ingestion on postprandial responses of glucose and insulin may be provided through attenuation in GLP-1 secretion along with its low digestibility into glucose. We suggest that the high-RS rice with ss3a/be2b may serve as a better carbohydrate source and also as a novel functional food for dietary interventions to improve postprandial hyperglycemia and hyperinsulinemia without both enhancing GLP-1 secretion and affecting gastric emptying in patients with diabetes.

Bromodomain Inhibition Reveals FGF15/19 As a Target of Epigenetic Regulation and Metabolic Control

Epigenetic regulation is an important factor in glucose metabolism, but underlying mechanisms remain largely unknown. Here we investigated epigenetic control of systemic metabolism by bromodomain-containing proteins (Brds), which are transcriptional regulators binding to acetylated histone, in both intestinal cells and mice treated with the bromodomain inhibitor JQ-1. In vivo treatment with JQ-1 resulted in hyperglycemia and severe glucose intolerance. Whole-body or tissue-specific insulin sensitivity was not altered by JQ-1; however, JQ-1 treatment reduced insulin secretion during both in vivo glucose tolerance testing and ex vivo incubation of isolated islets. JQ-1 also inhibited expression of fibroblast growth factor (FGF) 15 in the ileum and decreased FGF receptor 4-related signaling in the liver. These adverse metabolic effects of Brd4 inhibition were fully reversed by in vivo overexpression of FGF19, with normalization of hyperglycemia. At a cellular level, we demonstrate Brd4 binds to the promoter region of FGF19 in human intestinal cells; Brd inhibition by JQ-1 reduces FGF19 promoter binding and downregulates FGF19 expression. Thus, we identify Brd4 as a novel transcriptional regulator of intestinal FGF15/19 in ileum and FGF signaling in the liver and a contributor to the gut-liver axis and systemic glucose metabolism.

The Effects of Postprandial Walking on the Glucose Response after Meals with Different Characteristics

We evaluated the effect of postprandial walking on the post-meal glycemic response after meals with different characteristics. Twenty-one healthy young volunteers participated in one of two randomized repeated measures studies. Study 1 (10 participants) assessed the effects of 30 min of brisk walking after meals with different carbohydrate (CHO) content (0.75 or 1.5 g of CHO per kg/body weight). Study 2 (11 participants) evaluated the effects of 30 min of brisk walking after consuming a mixed meal or a CHO drink matched for absolute CHO content (75 g). Postprandial brisk walking substantially reduced (p < 0.009) the glucose peak in both studies, with no significant differences across conditions. When evaluating the glycemic response throughout the two hours post-meal, postprandial walking was more effective after consuming a lower CHO content (Study 1), and similarly effective after a mixed meal or a CHO drink (Study 2), although higher glucose values were observed when consuming the CHO drink. Our findings show that a 30 min postprandial brisk walking session improves the glycemic response after meals with different CHO content and macronutrient composition, with implications for postprandial exercise prescription in daily life scenarios.

Nutrients handling after bariatric surgery, the role of gastrointestinal adaptation

Bariatric surgery determines a rearrangement of the gastrointestinal tract that influences nutrient handling and plays a role in the metabolic changes observed after surgery. Most of the changes depend on the accelerated gastric emptying observed in Roux-en-Y gastric bypass (RYGB) and, to a lesser extent, in sleeve gastrectomy (SG). The rapid delivery of meal into the jejunum, particularly after RYGB, contributes to the prompt appearance of glucose in peripheral circulation. Glucose increase is the principal determinant of GLP-1 increase with the consequent stimulation of insulin secretion, the latter balanced by a paradoxical glucagon increase that stimulates EGP to prevent hypoglycaemia. Protein digestion and amino acid absorption appear accelerated after RYGB but not after SG. After RYGB, the adaptation of the gut to the new condition participates to the metabolic change. The intestinal transit is delayed, the gut microbioma is changed, the epithelium becomes hypertrophic and increases the expression of glucose transporter and of the number of cell secreting hormones. These changes are not observed after SG. After RYGB-less after SG-bile acids (BA) increase, influencing glucose metabolism probably modulating FXR and TGR5 with an effect on insulin sensitivity. Muscle, hepatic and adipose tissue insulin sensitivity improve, and the gut reinforces the recovery of IS by enhancing glucose uptake and through the effect of the BA. The intestinal changes observed after RYGB result in a light malabsorption of lipid but not of carbohydrate and protein. In conclusion, functional and morphological adaptations of the gut after RYGB and SG activate inter-organs cross-talk that modulates the metabolic changes observed after surgery.Level of evidence Level V, narrative literature review.

Inflammatory bowel disease and diabetes: Is there a link between them?

Patients with inflammatory bowel disease (IBD) are reported to have an increased risk of diabetes. IBD therapies may also modulate blood glucose substantially. These observations are indicative of mechanistic connection(s) between IBD and diabetes.

Hypothesis: Bolus jejunal feeding via an enteral feeding tube simulates key features of gastric bypass to initiate similar clinical benefits

BACKGROUND

Therapy for obesity and related comorbidities should be clinically effective, widely available and acceptable, and used in conjunction with an optimized lifestyle. Dieting is widely available and acceptable but has poorly sustained clinical efficacy. By contrast, Roux-en-Y gastric bypass (GB) is highly effective but cost and safety concerns limit widespread use. In this article this we discuss the hypothesis that bolus jejunal feeding (BJ) via an enteral feeding tube simulates key features of GB with the potential for similar clinical benefits. We further hypothesize that a practical manner of providing BJ therapeutically is via an externally inapparent orojejunal feeding tube.

RATIONALE

The first hypothesis is underpinned by the outcomes of research in three fields: 1) investigations into the mechanisms underlying the benefit of GB, 2) studies investigating gastrointestinal physiology and pathophysiology using enteral feeding tubes, and3) investigations into the mechanism underlying involuntary anorexia and weight loss in clinical situations that entail rapid nutrient delivery to the jejunum. There is compelling evidence that a supraphysiologic rate of delivery of nutrient to the jejunum suppresses appetite and energy intake and improves glucose homeostasis, and that these effects can be achieved non-surgically using an enteral feeding tube. The second hypothesis is supported by clinical demonstration of the feasibility of administering intermittent cycles of bolus feeds via an intraorally anchored feeding tube in ambulatory obese adults.

CONCLUSION

The hypotheses are testable in clinical studies. If validated, BJ could be used to induce the clinical benefits of GB, but without its costs or safety concerns.

Free fatty acid receptors in the endocrine regulation of glucose metabolism: Insight from gastrointestinal-pancreatic-adipose interactions

Glucose metabolism is primarily controlled by pancreatic hormones, with the coordinated assistance of the hormones from gastrointestine and adipose tissue. Studies have unfolded a sophisticated hormonal gastrointestinal-pancreatic-adipose interaction network, which essentially maintains glucose homeostasis in response to the changes in substrates and nutrients. Free fatty acids (FFAs) are the important substrates that are involved in glucose metabolism. FFAs are able to activate the G-protein coupled membrane receptors including GPR40, GPR120, GPR41 and GPR43, which are specifically expressed in pancreatic islet cells, enteroendocrine cells as well as adipocytes. The activation of FFA receptors regulates the secretion of hormones from pancreas, gastrointestine and adipose tissue to influence glucose metabolism. This review presents the effects of the FFA receptors on glucose metabolism via the hormonal gastrointestinal-pancreatic-adipose interactions and the underlying intracellular mechanisms. Furthermore, the development of therapeutic drugs targeting FFA receptors for the treatment of abnormal glucose metabolism such as type 2 diabetes mellitus is summarized.

The Risk of Type 2 Diabetes in Patients With Inflammatory Bowel Disease After Bowel Resections: A Nationwide Cohort Study

BACKGROUND AND AIMS:

Patients with inflammatory bowel disease (IBD) are at increased risk of type 2 diabetes (T2D), but the underlying mechanisms remain elusive. We aimed to determine the impact of small and large bowel resections on the risk of developing T2D in patients with IBD.

METHODS:

We conducted a nationwide, prospective study of all IBD patients undergoing small bowel resection (Crohn’s disease [CD]) and large bowel resection (CD and ulcerative colitis [UC]) in Denmark (1996–2018). Each patient was matched with up to 5 patients with IBD and no history of bowel resection. We used Cox proportional hazards regression models to estimate adjusted hazard ratios (aHRs) of T2D.

RESULTS:

We included 2469 patients with CD and small bowel resection, 1361 patients with CD and large bowel resection, and 3787 patients with UC and large bowel resection. Small bowel resection in CD patients was associated with lower risk of T2D (aHR 0.65, 95% CI, 0.44–0.92), compared with matched patients with CD and no bowel resection. Large bowel resection in patients with CD or UC was associated with aHRs of 0.95 (95% CI, 0.67–1.31) and 1.25 (95% CI, 1.03–1.51), respectively, compared with matched patients with CD or UC and no bowel resection.

CONCLUSION:

Patients with CD and small bowel resection have a lower risk of T2D, whereas patients with UC and large bowel resection have a higher risk of T2D, compared with patients with IBD and no bowel resection history. The underlying mechanisms remain to be explored.

A New Meal Absorption Model for Artificial Pancreas Systems

BACKGROUND

Artificial pancreas (AP) systems reduce the treatment burden of Type 1 Diabetes by automatically regulating blood glucose (BG) levels. While many disturbances stand in the way of fully closed-loop (automated) control, unannounced meals remain the greatest challenge. Furthermore, different types of meals can have significantly different glucose responses, further increasing the uncertainty surrounding the meal.

METHODS

Effective attenuation of a meal requires quick and accurate insulin delivery because of slow insulin action relative to meal effects on BG. The proposed Variable Hump (VH) model adapts to meals of varying compositions by inferring both meal size and shape. To appropriately address the uncertainty of meal size, the model divides meal absorption into two disjoint regions: a region with coarse meal size predictions followed by a fine-grain region where predictions are fine-tuned by adapting to the meal shape.

RESULTS

Using gold-standard triple tracer meal data, the proposed VH model is compared to three simpler second-order response models. The proposed VH model increased model fit capacity by 22% and prediction accuracy by 12% relative to the next best models. A 47% increase in the accuracy of uncertainty predictions was also found. In a simple control scenario, the controller governed by the proposed VH model provided insulin just as fast or faster than the controller governed by the other models in four out of the six meals. While the controllers governed by the other models all delivered at least a 25% excess of insulin at their worst, the VH model controller only delivered 9% excess at its worst.

CONCLUSIONS

The VH Model performed best in accuracy metrics and succeeded over the other models in providing insulin quickly and accurately in a simple implementation. Use in an AP system may improve prediction accuracy and lead to better control around mealtimes.

Streptozotocin-induced hyperglycemia alters the cecal metabolome and exacerbates antibiotic-induced dysbiosis

It is well established in the microbiome field that antibiotic (ATB) use and metabolic disease both impact the structure and function of the gut microbiome. But how host and microbial metabolism interacts with ATB susceptibility to affect the resulting dysbiosis remains poorly understood. In a streptozotocin-induced model of hyperglycemia (HG), we use a combined metagenomic, metatranscriptomic, and metabolomic approach to profile changes in microbiome taxonomic composition, transcriptional activity, and metabolite abundance both pre- and post-ATB challenge. We find that HG impacts both microbiome structure and metabolism, ultimately increasing susceptibility to amoxicillin. HG exacerbates drug-induced dysbiosis and increases both phosphotransferase system activity and energy catabolism compared to controls. Finally, HG and ATB co-treatment increases pathogen susceptibility and reduces survival in a Salmonella enterica infection model. Our data demonstrate that induced HG is sufficient to modify the cecal metabolite pool, worsen the severity of ATB dysbiosis, and decrease colonization resistance.

Antidiabetic effects of quercetin and liraglutide combination through modulation of TXNIP/IRS-1/PI3K pathway

The study was designed to assess the possible augmented antidiabetic effects of combining quercetin and liraglutide in a type 1 diabetes model, with emphasis on the contribution of hepatic thioredoxin interacting protein (TXNIP)/insulin receptor substrate 1 (IRS-1)/phosphatidyl inositol-3 kinase (PI3K) pathway. The wound-healing effects were also examined. Diabetes was induced by a single i.p STZ injection (55 mg/kg). Diabetic rats were treated with either quercetin (100 mg/kg/day, orally) or liraglutide (0.3 mg/kg/twice daily, S.C.) or their combination. Drugs were also applied topically on the wound. Blood glucose levels, serum albumin, total protein, total cholesterol and triglycerides were measured. Histopathological examination of the liver, pancreas and skin tissues was performed using haematoxylin and eosin staining. The hepatic malondialdehyde level was measured spectrophotometrically. Hepatic TXNIP and PI3K levels were measured by enzyme-linked immunsorbent assay (ELISA). Tissue expression of IRS-1 and phospho-IRS-1 (Ser 616) was assessed by immunohistochemistry. Quercetin, liraglutide and their combination effectively decreased blood glucose levels, improved lipid profile, upregulated albumin and total protein serum levels and reduced hepatic oxidative stress with the combination being most effective. Moreover, the combination group showed enhanced wound-healing effects and almost normalized hepatic and pancreatic histopathology. Quercetin and/or liraglutide significantly decreased TXNIP levels and serine phosphorylation of IRS-1 and increased PI3K levels compared to the diabetic untreated group. Interestingly, only the combination therapy normalized hepatic IRS-1 expression. The combination of quercetin and liraglutide showed enhanced antidiabetic effects, possibly through lowering hepatic TXNIP levels, with the resultant up-regulation of the IRS-1/PI3K pathway.

Fortifying a meal with oyster mushroom powder beneficially affects postprandial glucagon-like peptide-1, non-esterified free fatty acids and hunger sensation in adults with impaired glucose tolerance: a double-blind randomized controlled crossover trial

Purpose

Impaired glucose tolerance (IGT) is a pathophysiological condition characterized by insulin resistance with known metabolic consequences such as postprandial hyperglycemia and hypertriglyceridemia. We hypothesized that fortifying a meal with mushrooms rich in β-glucans may diminish glucose and triglyceride responses by improving postprandial gastrointestinal hormone release.

Methods

In a randomized controlled crossover study, 22 subjects with IGT ingested a meal either enriched with 20 g powder (8.1 g β-glucans) of oven-dried Pleurotus ostreatus (enriched meal, EN) or without enrichment (control meal, CON). Blood was collected before and repeatedly within 4 h after the meal to determine AUC of glucose (primary outcome), insulin, triglycerides, non-esterified free fatty acids (NEFAs), glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP) and ghrelin. Appetite sensations (hunger, satiety, fullness, and desire to eat) were assessed before and after meal consumption by visual analog scales.

Results

Postprandial glucose, insulin, triglycerides, GIP and ghrelin concentrations as well as the corresponding AUCs did not differ between EN and CON. NEFAs-AUC was 14% lower (P = 0.026) and GLP-1-AUC 17% higher (P = 0.001) after EN compared to CON. Appetite ratings did not differ between treatments, except for hunger (AUC 22% lower after EN vs. CON; P = 0.031).

Conclusion

The observed immediate postprandial metabolic changes indicate that an easily manageable fortification of a single meal with powder from dried oyster mushrooms as β-glucan source may improve postprandial metabolism. If the effect is preserved long term, this measure can diminish the risk for further development of overweight/obesity and type 2 diabetes in subjects with IGT.

Clinical trial registration

German Clinical Trial Register on 09/08/2018; trial-ID: DRKS00015244.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-021-02674-1.

Mahalanobis distance, a novel statistical proxy of homeostasis loss is longitudinally associated with risk of type 2 diabetes

Background

The potential role of individual plasma biomarkers in the pathogenesis of type 2 diabetes (T2D) has been broadly studied, but the impact of biomarkers interaction remains underexplored. Recently, the Mahalanobis distance (MD) of plasma biomarkers has been proposed as a proxy of physiological dysregulation. Here we aimed to investigate whether the MD calculated from circulating biomarkers is prospectively associated with development of T2D.

Methods

We calculated the MD of the Principal Components (PCs) integrating the information of 32 circulating biomarkers (comprising inflammation, glycemic, lipid, microbiome and one-carbon metabolism) measured in 6247 participants of the PREVEND study without T2D at baseline. Cox proportional-hazards regression analyses were performed to study the association of MD with T2D development.

Findings

After a median follow-up of 7·3 years, 312 subjects developed T2D. The overall MD (mean (SD)) was higher in subjects who developed T2D compared to those who did not: 35·65 (26·67) and 30.75 (27·57), respectively (P = 0·002). The highest hazard ratio (HR) was obtained using the MD calculated from the first 31 PCs (per 1 log-unit increment) (1·72 (95% CI 1·42,2·07), P < 0·001). Such associations remained after the adjustment for age, sex, plasma glucose, parental history of T2D, lipids, blood pressure medication, and BMI (HR_adj 1·37 (95% CI 1·11,1·70), P = 0·004).

Interpretation

Our results are in line with the premise that MD represents an estimate of homeostasis loss. This study suggests that MD is able to provide information about physiological dysregulation also in the pathogenesis of T2D.

Funding

The Dutch Kidney Foundation (Grant E.033).