The effects of prebiotics on gastrointestinal side effects of metformin in youth: A pilot randomized control trial in youth-onset type 2 diabetes

Metformin: Diverse molecular mechanisms, gastrointestinal effects and overcoming intolerance in type 2 Diabetes Mellitus: A review

Metformin, the first line treatment for patients with type 2 diabetes mellitus, has alternative novel roles, including cancer and diabetes prevention. This narrative review aims to explore its diverse mechanisms, effects and intolerance, using sources obtained by searching Scopus, PubMed and Web of Science databases, and following Scale for the Assessment of Narrative Review Articles reporting guidelines. Metformin exerts it actions through duration influenced, and organ specific, diverse mechanisms. Its use is associated with inhibition of hepatic gluconeogenesis targeted by mitochondria and lysosomes, reduction of cholesterol levels involving brown adipose tissue, weight reduction influenced by growth differentiation factor 15 and novel commensal bacteria, in addition to counteraction of meta-inflammation alongside immuno-modulation. Interactions with the gastrointestinal tract include alteration of gut microbiota, enhancement of glucose uptake and glucagon like peptide 1 and reduction of bile acid absorption. Though beneficial, they may be linked to intolerance. Metformin related gastrointestinal adverse effects are associated with dose escalation, immediate release formulations, gut microbiota alteration, epigenetic predisposition, inhibition of organic cation transporters in addition to interactions with serotonin, histamine and the enterohepatic circulation. Potentially effective measures to overcome intolerance encompasses carefully objective targeted dose escalation, prescription of fixed dose combination, microbiome modulators and prebiotics, in addition to use of extended release formulations.

Gastrointestinal adverse effects of old and new antidiabetics: How do we deal with them in real life?

Diabetes is a public health problem with an estimated worldwide prevalence of 10% and a prevalence of 12% in Mexico. The costs resulting from this chronic-degenerative disease are significant. Treatment for diabetes involves different medication groups, some of which can cause significant gastrointestinal adverse effects, such as dyspepsia, nausea, vomiting, bloating, diarrhea, and constipation. The medications most frequently associated with said adverse effects are metformin, acarbose, and GLP-1 agonists. Gastrointestinal adverse effects negatively impact the quality of life and management of patients with diabetes. The factors of visceral neuropathy, acute dysglycemia, dysbiosis, and intestinal bacterial overgrowth contribute to the gastrointestinal symptoms in patients with diabetes, making it necessary to consider multiple etiologic factors in the presence of gastrointestinal symptoms, and not exclusively attribute them to the use of antidiabetics. Personalized treatment, considering gastrointestinal comorbidity and the type of drug utilized, is essential for mitigating the adverse effects and improving the quality of life in patients with diabetes. The aim of the present narrative review was to describe the gastrointestinal adverse effects of the antidiabetic drugs, their pathophysiologic mechanisms, and the corresponding therapeutic measures.

Metformin-Associated Gastrointestinal Adverse Events Are Reduced by Probiotics: A Meta-Analysis

Metformin, one of the most frequently used oral glucose-lowering drugs (GLDs), is associated with the occurrence of gastrointestinal (GI) adverse events in approximately 20% of users. These unwanted actions result in non-compliance or even discontinuation of metformin therapy. The aim of the presented meta-analysis was to determine whether adding a drug from the group of sulfonylureas, glitazones, DPP-IV inhibitors, or probiotics to metformin monotherapy may affect the risk of GI side effects. The material for this meta-analysis comprised data from 26 randomized controlled clinical trials (RCTs) published in English. This meta-analysis included 41,048 patients. The PubMed, Cochrane Library, and Clinical Trials databases were thoroughly searched to find relevant RCTs. The Population, Intervention, Comparison, Outcomes, and Study Type (PICOT) structure was used to formulate study selection criteria and the research question. Cochrane Review Manager Software 5.4 was used to carry out analysis of collected data. The results were presented as relative risk (RR) and 95% confidence interval (95% CI) for each group, and p < 0.05 was considered as statistically significant. As expected from clinical practice, metformin was associated with a markedly increased risk of abdominal pain, nausea, and vomiting compared to placebo. In comparison to other GLDs, taking metformin was related to an elevated risk of diarrhea and abdominal pain and to a lowered risk of vomiting and bloating. In turn, adding other GLDs to metformin treatment was associated with an elevated risk of nausea and vomiting than treatment with metformin in monotherapy. However, adding probiotics to metformin therapy was related to a decreased risk of diarrhea, bloating, and constipation. The obtained results demonstrate that the combination of metformin with other GLDs may elevate the risk of nausea and vomiting, whereas combination with probiotics decreases the risk of diarrhea, bloating, and constipation. Thus, the results of our meta-analysis suggest that probiotics may reduce the risk of some GI side effects in people with type 2 diabetes mellitus (T2DM) who started treatment with metformin.

Understanding how pre- and probiotics affect the gut microbiome and metabolic health

The gut microbiome, a complex assembly of microorganisms, significantly impacts human health by influencing nutrient absorption, the immune system, and disease response. These microorganisms form a dynamic ecosystem that is critical to maintaining overall well-being. Prebiotics and probiotics are pivotal in regulating gut microbiota composition. Prebiotics nourish beneficial bacteria and promote their growth, whereas probiotics help maintain balance within the microbiome. This intricate balance extends to several aspects of health, including maintaining the integrity of the gut barrier, regulating immune responses, and producing metabolites crucial for metabolic health. Dysbiosis, or an imbalance in the gut microbiota, has been linked to metabolic disorders such as type 2 diabetes, obesity, and cardiovascular disease. Impaired gut barrier function, endotoxemia, and low-grade inflammation are associated with toll-like receptors influencing proinflammatory pathways. Short-chain fatty acids derived from microbial fermentation modulate anti-inflammatory and immune system pathways. Prebiotics positively influence gut microbiota, whereas probiotics, especially Lactobacillus and Bifidobacterium strains, may improve metabolic outcomes, such as glycemic control in diabetes. It is important to consider strain-specific effects and study variability when interpreting these findings, highlighting the need for further research to optimize their therapeutic potential. The aim of this report is therefore to review the role of the gut microbiota in metabolic health and disease and the effects of prebiotics and probiotics on the gut microbiome and their therapeutic role, integrating a broad understanding of physiological mechanisms with a clinical perspective.

Glycemia and Gluconeogenesis With Metformin and Liraglutide: A Randomized Trial in Youth-onset Type 2 Diabetes

OBJECTIVE

Elevated rates of gluconeogenesis are an early pathogenic feature of youth-onset type 2 diabetes (Y-T2D), but targeted first-line therapies are suboptimal, especially in African American (AA) youth. We evaluated glucose-lowering mechanisms of metformin and liraglutide by measuring rates of gluconeogenesis and β-cell function after therapy in AA Y-T2D.

METHODS

In this parallel randomized clinical trial, 22 youth with Y-T2D-age 15.3 ± 2.1 years (mean ± SD), 68% female, body mass index (BMI) 40.1 ± 7.9 kg/m2, duration of diagnosis 1.8 ± 1.3 years-were randomized to metformin alone (Met) or metformin + liraglutide (Lira) (Met + Lira) and evaluated before and after 12 weeks. Stable isotope tracers were used to measure gluconeogenesis [2H2O] and glucose production [6,6-2H2]glucose after an overnight fast and during a continuous meal. β-cell function (sigma) and whole-body insulin sensitivity (mSI) were assessed during a frequently sampled 2-hour oral glucose tolerance test.

RESULTS

At baseline, gluconeogenesis, glucose production, and fasting and 2-hour glucose were comparable in both groups, though Met + Lira had higher hemoglobin A1C. Met + Lira had a greater decrease from baseline in fasting glucose (-2.0 ± 1.3 vs -0.6 ± 0.9 mmol/L, P = .008) and a greater increase in sigma (0.72 ± 0.68 vs -0.05 ± 0.71, P = .03). The change in fractional gluconeogenesis was similar between groups (Met + Lira: -0.36 ± 9.4 vs Met: 0.04 ± 12.3%, P = .9), and there were no changes in prandial gluconeogenesis or mSI. Increased glucose clearance in both groups was related to sigma (r = 0.63, P = .003) but not gluconeogenesis or mSI.

CONCLUSION

Among Y-T2D, metformin with or without liraglutide improved glycemia but did not suppress high rates of gluconeogenesis. Novel therapies that will enhance β-cell function and target the elevated rates of gluconeogenesis in Y-T2D are needed.

An Update on Prebiotics and on Their Health Effects

Prebiotic compounds were originally defined as "a nondigestible food ingredient that beneficially affects the host by selectively stimulating the growth and/or activity of one or a limited number of bacteria in the colon, and thus improves host health"; however, a significant modulation of the definition was carried out in the consensus panel of The International Scientific Association for Probiotics and Prebiotics (ISAPP), and the last definition states that "prebiotics are substrates that are selectively utilized by host microorganisms conferring a health benefit". Health effects of prebiotics compounds attracted the interest of researchers, food companies and Regulatory Agencies, as inferred by the number of articles on Scopus for the keywords "prebiotic" and "health effects", that is ca. 2000, for the period January 2021-January 2024. Therefore, the aim of this paper is to contribute to the debate on these topics by offering an overview of existing knowledge and advances in this field. A literature search was performed for the period 2012-2023 and after the selection of the most relevant items, the attention was focused on seven conditions for which at least 8-10 different studies were found, namely colorectal cancer, neurological or psychiatric conditions, intestinal diseases, obesity, diabetes, metabolic syndrome, and immune system disorders. In addition, the analysis of the most recent articles through the software VosViewer version 1.6.20 pointed out the existence of five clusters or macro-categories, namely: (i) pathologies; (ii) metabolic condvitions; (iii) structure and use in food; (iv) immunomodulation; (v) effect on gut microbiota.

Prebiotics Progress Shifts in the Intestinal Microbiome That Benefits Patients with Type 2 Diabetes Mellitus

Hypoglycemic medications that could be co-administered with prebiotics and functional foods can potentially reduce the burden of metabolic diseases such as Type 2 Diabetes Mellitus (T2DM). The efficacy of drugs such as metformin and sulfonylureas can be enhanced by the activity of the intestinal microbiome elaborated metabolites. Functional foods such as prebiotics (e.g., oligofructose) and dietary fibers can treat a dysbiotic gut microbiome by enhancing the diversity of microbial niches in the gut. These beneficial shifts in intestinal microbiome profiles include an increased abundance of bacteria such as Faecalibacterium prauznitzii, Akkermancia muciniphila, Roseburia species, and Bifidobacterium species. An important net effect is an increase in the levels of luminal SCFAs (e.g., butyrate) that provide energy carbon sources for the intestinal microbiome in cross-feeding activities, with concomitant improvement in intestinal dysbiosis with attenuation of inflammatory sequalae and improved intestinal gut barrier integrity, which alleviates the morbidity of T2DM. Oligosaccharides administered adjunctively with pharmacotherapy to ameliorate T2DM represent current plausible treatment modalities.

Targeting metabolic pathways: a novel therapeutic direction for type 2 diabetes

Background

Type 2 diabetes mellitus (T2DM) is a prevalent metabolic disease that causes multi-organ complications, seriously affecting patients' quality of life and survival. Understanding its pathogenesis remains challenging, with current clinical treatment regimens often proving ineffective.

Methods

In this study, we established a mouse model of T2DM and employed 16s rDNA sequencing to detect changes in the species and structure of gut flora. Additionally, we used UPLC-Q-TOF-MS to identify changes in urinary metabolites of T2DM mice, analyzed differential metabolites and constructed differential metabolic pathways. Finally, we used Pearman correlation analysis to investigate the relationship between intestinal flora and differential metabolites in T2DM mice, aiming to elucidate the pathogenesis of T2DM and provide an experimental basis for its clinical treatment.

Results

Our findings revealed a reduction in both the species diversity and abundance of intestinal flora in T2DM mice, with significantly decreased levels of beneficial bacteria such as Lactobacillus and significantly increased levels of harmful bacteria such as Helicobacter pylori. Urinary metabolomics results identified 31 differential metabolites between T2DM and control mice, including Phosphatidylcholine, CDP-ethanolamine and Leukotriene A4, which may be closely associated with the glycerophospholipid and arachidonic acid pathways. Pearman correlation analysis showed a strong correlation between dopamine and gonadal, estradiol and gut microbiota, may be a novel direction underlying T2DM.

Conclusion

In conclusion, our study suggests that alterations in gut microbiota and urinary metabolites are characteristic features of T2DM in mice. Furthermore, a strong correlation between dopamine, estradiol and gut microbiota, may be a novel direction underlying T2DM, the aim is to provide new ideas for clinical treatment and basic research.