Glucagon-like peptide 1 in health and disease

A cross-over study of postprandial effects from moist snuff and red wine on metabolic rate, appetite-related hormones and glucose

PURPOSE

To compare acute effects of moist snuff with or without nicotine and red wine with or without alcohol on prandial hormones and metabolism.

BASIC PROCEDURES AND METHODS

Two deciliters of wine, with or without alcohol, were taken together with a standardized supervised meal in 14 healthy women and men. All participants also combined the meal with usage of with moist snuff, with or without nicotine. The snuff was replaced hourly at each of the four settings, i.e. snuff with or without nicotine combined with red wine with or without alcohol, that started at 0800 o'clock and were finished at noon.

MAIN FINDINGS

We found ghrelin levels to be more efficiently suppressed when drinking red wine with alcohol compared to non-alcoholic wine by analyzing area under the curve (AUC). AUC for regular wine was 370 ± 98 pg/ml x hours and 559 ± 154 pg/ml x hours for de-alcoholized red wine, p < 0.0001 by general linear model. The postprandial metabolic rate was further elevated following alcohol containing red wine compared with non-alcoholic red wine (p = 0.022). Although glucose levels were not uniformly lower after alcoholic red wine, we found lowered glucose levels 3 h after the meal (mean glucose wine: 4.38 ± 0.96 mmol/l, non-alcoholic wine: 4.81 ± 0.77 mmol/l, p = 0.005). Nicotine-containing moist snuff (AUC: 1406 ± 149 nmol/ml x hours) elevated the levels of serum cortisol compared with nicotine-free snuff (AUC: 1268 ± 119 nmol/ml x hours, p = 0.005). We found no effects of nicotine or alcohol on feelings of satiety.

CONCLUSIONS

Alcohol in red wine augmented the postprandial suppression of ghrelin and it also lowered postprandial glucose 3 h post-meal. These effects are in line with observational trials linking regular intake of moderate amounts of red wine with lower risk for diabetes.

The Mechanism of Action of Biguanides: New Answers to a Complex Question

Biguanides are a family of antidiabetic drugs with documented anticancer properties in preclinical and clinical settings. Despite intensive investigation, how they exert their therapeutic effects is still debated. Many studies support the hypothesis that biguanides inhibit mitochondrial complex I, inducing energy stress and activating compensatory responses mediated by energy sensors. However, a major concern related to this “complex” model is that the therapeutic concentrations of biguanides found in the blood and tissues are much lower than the doses required to inhibit complex I, suggesting the involvement of additional mechanisms. This comprehensive review illustrates the current knowledge of pharmacokinetics, receptors, sensors, intracellular alterations, and the mechanism of action of biguanides in diabetes and cancer. The conditions of usage and variables affecting the response to these drugs, the effect on the immune system and microbiota, as well as the results from the most relevant clinical trials in cancer are also discussed.

GZR18, a novel long-acting GLP-1 analog, demonstrated positive in vitro and in vivo pharmacokinetic and pharmacodynamic characteristics in animal models

GZR18 is a novel analog of glucagon-like peptide-1 (GLP-1). This study evaluates the pharmacology, pharmacokinetics, and efficacy of GZR18, and its potential for the treatment of Type 2 diabetes mellitus (T2DM). In vitro pharmacology and activity of GZR18 were characterized by a binding assay of GZR18 using human serum albumin (HSA), an activation assay in human GLP-1 receptor-expressing cell lines, and its effect on glucose-stimulated insulin secretion (GSIS) in primary mice islets. Pharmacokinetic profiling was performed in Sprague Dawley rats and cynomolgus monkeys, and efficacy evaluated using GZR18 single or repeated doses in db/db mice. GZR18 showed similar binding affinity for HSA and GLP-1 receptor compared with semaglutide and liraglutide. GZR18 increased GSIS, which was confirmed by dynamic islet perifusion and fluorescence imaging using PKZnR-5 for real-time detection. In cynomolgus monkeys, the average GZR18 maximal concentration was 527 nmol L^-1, the terminal half-life (T_1/2) was 61.3 h, and the time to maximum concentration was 14 h. Single-dose GZR18 lowered blood glucose levels and reduced body weight over 72 h in db/db mice. GZR18 successive administration (every three days for 33 days, i.e. 11 doses) lowered nonfasting and fasting blood glucose levels (p < 0.05 versus control) and glycated hemoglobin, following the 11th dose. Food and water consumption in db/db mice was lowered following repeated doses of GZR18 (p < 0.05 versus control), without a reduction in body weight. These results demonstrate the potential of GZR18 as a long-acting GLP-1 analog for the treatment of T2DM.

Counteracting Health Risks by Modulating Homeostatic Signaling

Homeostasis was initially conceptualized by Bernard and Cannon around a century ago as a steady state of physiological parameters that vary within a certain range, such as blood pH, body temperature, and heart rate^1,2. The underlying mechanisms that maintain homeostasis are explained by negative feedbacks that are executed by the neuronal, endocrine, and immune systems. At the cellular level, homeostasis, such as that of redox and energy steady state, also exists and is regulated by various cell signaling pathways. The induction of homeostatic mechanism is critical for human to adapt to various disruptive insults (stressors); while on the other hand, adaptation occurs at the expense of other physiological processes and thus runs the risk of collateral damages, particularly under conditions of chronic stress. Conceivably, anti-stress protection can be achieved by stressor-mimicking medicinals that elicit adaptive responses prior to an insult and thereby serve as health risk countermeasures; and in situations where maladaptation may occur, downregulating medicinals could be used to suppress the responses and prevent subsequent pathogenesis. Both strategies are preemptive interventions particularly suited for individuals who carry certain lifestyle, environmental, or genetic risk factors. In this article, we will define and characterize a new modality of prophylactic intervention that forestalls diseases via modulating homeostatic signaling. Moreover, we will provide evidence from the literature that support this concept and distinguish it from other homeostasis-related interventions such as adaptogen, hormesis, and xenohormesis.

Is Time-Restricted Eating Safe in the Treatment of Type 2 Diabetes?-A Review of Intervention Studies

Time-restricted eating (TRE) has been shown to improve body weight and glucose metabolism in people at high risk of type 2 diabetes. However, the safety of TRE in the treatment of type 2 diabetes is unclear. We investigated the safety of TRE interventions in people with type 2 diabetes by identifying published and ongoing studies. Moreover, we identified the commonly used antidiabetic drugs and discussed the safety of TRE in people with type 2 diabetes considering the use of these drugs. In addition, we addressed the research needed before TRE can be recommended in the treatment of type 2 diabetes. A literature search was conducted to identify published (MEDLINE PubMed) and ongoing studies (ClinicalTrials.gov) on TRE in people with type 2 diabetes. To assess the usage of antidiabetic drugs and to discuss pharmacodynamics and pharmacokinetics in a TRE context, the most used antidiabetic drugs were identified and analysed. Statistics regarding sale of pharmaceuticals were obtained from MEDSTAT.DK which are based on data from the national Register of Medicinal Product Statistics, and from published studies on medication use in different countries. Four published studies investigating TRE in people with type 2 diabetes were identified as well as 14 ongoing studies. The completed studies suggested that TRE is safe among people with type 2 diabetes. Common antidiabetic drugs between 2010 and 2019 were metformin, insulin, dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, sulfonylureas, and sodium-glucose cotransporter-2 inhibitors. Existing studies suggest that TRE is not associated with major safety issues in people with type 2 diabetes as long as medication is monitored and adjusted. However, because of low generalisability of the few studies available, more studies are needed to make concrete recommendations regarding efficacy and safety of TRE in people with type 2 diabetes.

Real-world evidence on the use of a fixed-ratio combination of insulin glargine and lixisenatide (iGlarLixi) in people with suboptimally controlled type 2 diabetes in Romania: a prospective cohort study (STAR.Ro)

OBJECTIVES

To assess the effectiveness and safety of insulin glargine and lixisenatide (iGlarLixi) fixed-ratio combination on a cohort of Romanian adults with type 2 diabetes (T2D).

DESIGN

Open-label, 24-week, prospective cohort study.

SETTING

65 secondary care diabetes centres in Romania.

PARTICIPANTS

The study included 901 adults with T2D suboptimally controlled with previous oral antidiabetic drugs (OADs)±basal insulin (BI) who initiated treatment with iGlarLixi upon the decision of the investigator. Major exclusion criteria were iGlarLixi contraindications and refusal to participate. 876 subjects received at least one dose of iGlarLixi (intention-to-treat/safety population).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary endpoint was change in glycated haemoglobin (HbA1c) from baseline to week 24 in the modified intention-to-treat population (study participants with HbA1c available at baseline and week 24). Secondary efficacy outcomes were percentage of participants reaching HbA1c targets and change in fasting plasma glucose (FPG).

RESULTS

Mean baseline HbA1c was 9.2% (SD 1.4) and FPG was 10.8 mmol/L (2.9). Mean HbA1c change was -1.3% (95% CI: -1.4% to -1.2%, p<0.0001) at week 24. HbA1c levels ≤6.5%, <7% and<7.5% at week 24 were achieved by 72 (8.9%), 183 (22.6%) and 342 (42.3%) participants, respectively. Mean FPG change was -3.1 mmol/L (95% CI: -3.3 to -2.8, p<0.001) at week 24. Mean body weight change was -1.6 kg (95% CI: -1.9 to -1.3, p<0.001) at 24 weeks. Mean iGlarLixi dose increased from 19.5 U (SD 7.7) and 30.1 U (10.0) to 30.2 U (8.9) (ratio 2/1 pen) and 45.0 U (11.6) (ratio 3/1 pen). Adverse events (AEs) were reported by 43 (4.9%) participants (18 (2.1%) gastrointestinal) with 4 (0.5%) reporting serious AEs. 13 (1.5%) participants reported at least one event of symptomatic hypoglycaemia, with one episode of severe hypoglycaemia reported.

CONCLUSIONS

In a real-world setting, 24-week treatment with iGlarLixi provided a significant reduction of HbA1c with body weight loss and low hypoglycaemia risk in T2D suboptimally controlled with OADs±BI treatment.

Insights into new therapeutic approaches for the treatment and management of polycystic ovary syndrome: An updated review

BACKGROUND

Polycystic ovary syndrome (PCOS) is a long-term, highly prevalent, complex heterogeneous, polygenic endocrine disorder characterized by both metabolic and reproductive disorders. It affects 6-23% of reproductive age women globally.

OBJECTIVE

This review aims to facilitate an understanding of novel PCOS management approaches and highlights the results from relevant interventional studies from animal and human studies.

METHODS

Manual search on PubMed, Cochrane, Scopus databases was performed for relevant articles, preclinical and clinical trials based on related keywords.

RESULTS

According to a multitude of studies, PCOS has evolved over time, but a substantial lag remains in management approaches. New insights into the cross-talk between muscle, brain, fat, and ovaries pointed out new therapeutic targets. This review has highlighted the efficacy of a wide spectrum of novel therapeutic agents [Phosphodiesterase-4 Inhibitors, Glucagon-like peptide-1 receptor agonists, nutritional supplements (Vitamins D and K, omega-3, prebiotics, probiotics and synbiotics), fecal microbiota transplantation (FMT) and intestinal cytokine IL-22] as PCOS therapeutic options. These novel therapies combine anti-inflammatory, insulin sensitizing, anti-obesity, and restoration of the gut microbiota and thus hold the potential to address the basic pathogenic mechanisms of PCOS.

CONCLUSION

Exhaustive, multicentric and multiethnic studies are vital to generate a network of normative data to better figure out the PCOS trajectory and change prognostic outcomes. Preclinical and clinical data is warranted to corroborate the new therapeutics and direct health care resources accordingly.

Synthesis and biological evaluation of glucagon-like peptide-1 analogs with the C-terminal helix 3 of albumin-binding domain 3

Based on peptide 6 (Ser⁸-GLP-1 [7-35]-GVKALIDEILAA-NH₂; GVKALI-DEILAA is the C-terminal helix 3 of albumin-binding domain 3 of protein G from bacterial Streptococcal G strain 148 [G148-ABD3]), a series of its analogs (compounds 0-VI: Aib⁸-GLP-1 [7-35]-linkers-GVKALIDEILAA-NH₂) were designed and synthesized using microwave-assisted solid-phase synthesis. First, to monitor the reaction process and reduce potential risks, the synthesis process of compounds 0-VI was divided into three stages. Next, to explore the effect of these linkers on their albumin-binding rates, albumin-binding assays were performed. Finally, to evaluate their biological activities in vitro and in vivo, receptor potency, surface plasmon resonance (SPR), weight-loss, and glucose-lowering assays were carried out. These results indicated the linkers of different polarities between Aib⁸-GLP-1 (7-35) and the C-terminal helix 3 of ABD3 can significantly affect the albumin-binding rate of the C-terminal helix 3 of ABD3. And compound IV had the highest albumin-binding rates, weight-loss, and glucose-lowering effects among them.

N-terminal alterations turn the gut hormone GLP-2 into an antagonist with gradual loss of GLP-2 receptor selectivity towards more GLP-1 receptor interaction

BACKGROUND AND PURPOSE

To fully elucidate the regulatory role of the GLP-2 system in the gut and the bones, potent and selective GLP-2 receptor (GLP-2R) antagonists are needed. Searching for antagonist activity, we performed systematic N-terminal truncations of human GLP-2(1-33).

EXPERIMENTAL APPROACH

COS-7 cells were transfected with the human GLP-2R and assessed for cAMP accumulation or competition binding using ¹²⁵ I-GLP-2(1-33)[M10Y]. To examine selectivity, human GLP-1 or GIP receptor expressing COS-7 cells were assessed for cAMP accumulation.

KEY RESULTS

The affinity for the GLP-2R of the N-terminally truncated GLP-2 peptides decreased with reduced N-terminal peptide length (K_i 6.5-871 nM), while increasing antagonism appeared with inhibitory potencies (IC₅₀ ) values from 79 to 204 nM for truncation up to GLP-2(4-33) and then declined. In contrast, truncation-dependent increases in intrinsic activity were observed from an E_max of only 20% for GLP-(2-33) up to 46% for GLP-2(6-33) at 1 μM, followed by a decline. GLP-2(9-33) had the highest intrinsic efficacy (E_max 65%) and no antagonistic properties. Moreover, with truncations up to GLP-2(8-33) a gradual loss in selectivity for the GLP-2R appeared with increasing GLP-1 receptor (GLP-1R) inhibition (up to 73% at 1 μM). Lipidation of the peptides improved antagonism (IC₅₀ down to 7.9 nM) for both the GLP-2R and the GLP-1R.

CONCLUSION AND IMPLICATIONS

The N-terminus of GLP-2 is crucial for GLP-2R activity and selectivity. Our observations form the basis for the development of tool compounds for further characterization of the GLP-2 system.

Circadian alignment of early onset caloric restriction promotes longevity in male C57BL/6J mice

Caloric restriction (CR) prolongs lifespan, yet the mechanisms by which it does so remain poorly understood. Under CR, mice self-impose chronic cycles of 2-hour-feeding and 22-hour-fasting, raising the question whether calories, fasting, or time of day are causal. We show that 30%-CR is sufficient to extend lifespan 10%; however, a daily fasting interval and circadian-alignment of feeding act together to extend lifespan 35% in male C57BL/6J mice. These effects are independent of body weight. Aging induces widespread increases in gene expression associated with inflammation and decreases in expression of genes encoding components of metabolic pathways in liver from ad lib fed mice. CR at night ameliorates these aging-related changes. Thus, circadian interventions promote longevity and provide a perspective to further explore mechanisms of aging.

Timed caloric restriction at night enhances longevity.

A novel strategy for production of liraglutide precursor peptide and development of a new long-acting incretin mimic

Nowadays, a small number of incretin mimics are used to treat type 2 diabetes mellitus (T2DM) due to their longer half-life. The present study aimed to introduce a novel method for producing the liraglutide precursor peptide (LPP) and developing a potentially new incretin mimic. Here, human αB-crystallin (αB-Cry) was ligated to the LPP at the gene level, and the gene construct was expressed in Escherichia coli with a relatively good efficiency. The hybrid protein (αB-lir) was then purified by a precipitation method followed by anion exchange chromatography. After that, the peptide was released from the carrier protein by a chemical cleavage method yielding about 70%. The LPP was then purified by gel filtration chromatography, and HPLC estimated its purity to be about 98%. Also, the molecular mass of the purified peptide was finally confirmed by mass spectroscopy analysis. Assessment of the secondary structures suggested a dominant α-helical structure for the LPP and a β-sheet rich structure for the hybrid protein. The subcutaneous injection of the LPP and the αB-lir hybrid protein significantly reduced the blood sugar levels in healthy and diabetic mice and stimulated insulin secretion. Also, the hybrid protein exerts its bioactivities more effectively than the LPP over a relatively longer period of time. The results of this study suggested a novel method for the easy and cost-effective production of the LPP and introduced a new long-acting incretin mimic that can be potentially used for the treatment of T2DM patients.

GLP-1 and GIP receptor signaling in beta cells - A review of receptor interactions and co-stimulation

Glucagon-like peptide 1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) are two class B1 G protein-coupled receptors, which are stimulated by the gastrointestinal hormones GLP-1 and GIP, respectively. In the pancreatic beta cells, activation of both receptors lead to increased cyclic adenosine monophosphate (cAMP) and glucose-dependent insulin secretion. Marketed GLP-1R agonists such as dulaglutide, liraglutide, exenatide and semaglutide constitute an expanding drug class with beneficial effects for persons suffering from type 2 diabetes and/or obesity. In recent years another drug class, the GLP-1R-GIPR co-agonists, has emerged. Especially the peptide-based, co-agonist tirzepatide is a promising candidate for a better treatment of type 2 diabetes by improving glycemic control and weight reduction. The mechanism of action for tirzepatide include biased signaling of the GLP-1R as well as potent GIPR signaling. Since the implications of co-targeting these closely related receptors concomitantly are challenging to study in vivo, the pharmacodynamic mechanisms and downstream signaling pathways of the GLP-1R-GIPR co-agonists in general, are not fully elucidated. In this review, we present the individual signaling pathways for GLP-1R and GIPR in the pancreatic beta cell with a focus on the shared signaling pathways of the two receptors and interpret the implications of GLP-1R-GIPR co-activation in the light of recent co-activating therapeutic compounds.

Cardiovascular effects of GLP-1 receptor agonism

Glucagon-like peptide-1 (GLP-1) receptor agonists are extensively used in type 2 diabetic patients for the effective control of hyperglycemia. It is now clear from outcomes trials that this class of drugs offers important additional benefits to these patients due to reducing the risk of developing major adverse cardiac events (MACE). This risk reduction is, in part, due to effective glycemic control in patients; however, the various outcomes trials, further validated by subsequent meta-analysis of the outcomes trials, suggest that the risk reduction in MACE is also dependent on glycemic-independent mechanisms operant in cardiovascular tissues. These glycemic-independent mechanisms are likely mediated by GLP-1 receptors found throughout the cardiovascular system and by the complex signaling cascades triggered by the binding of agonists to the G-protein coupled receptors. This heterogeneity of signaling pathways underlying different downstream effects of GLP-1 agonists, and the discovery of biased agonists favoring specific signaling pathways, may have import in the future treatment of MACE in these patients. We review the evidence supporting the glycemic-independent evidence for risk reduction of MACE by the GLP-1 receptor agonists and highlight the putative mechanisms underlying these benefits. We also comment on the different signaling pathways which appear important for mediating these effects.

Citrus Extract as a Perspective for the Control of Dyslipidemia: A Systematic Review With Meta-Analysis From Animal Models to Human Studies

This study aims to obtain scientific evidence on the use of Citrus to control dyslipidemia. The surveys were carried out in 2020 and updated in March 2021, in the PubMed, Scopus, LILACS, and SciELO databases, using the following descriptors: Citrus, dyslipidemias, hypercholesterolemia, hyperlipidemias, lipoproteins, and cholesterol. The risk of bias was assessed according to the Cochrane methodology for clinical trials and ARRIVE for preclinical trials. A meta-analysis was performed using the application of R software. A total of 958 articles were identified and 26 studies demonstrating the effectiveness of the Citrus genus in controlling dyslipidemia were selected, of which 25 were included in the meta-analysis. The effects of Citrus products on dyslipidemia appear consistently robust, acting to reduce total cholesterol, LDL, and triglycerides, in addition to increasing HDL. These effects are associated with the composition of the extracts, extremely rich in antioxidant, as flavonoids, and that act on biochemical targets involved in lipogenesis and beta-oxidation. The risk of bias over all of the included studies was considered critically low to moderate. The meta-analysis demonstrated results favorable to control dyslipidemia by Citrus products. On the other hand, high heterogeneity values were identified, weakening the evidence presented. From this study, one can suggest that Citrus species extracts are potential candidates for dyslipidemia control, but more studies are needed to increase the strength of this occurrence.

Satiety Associated with Calorie Restriction and Time-Restricted Feeding: Peripheral Hormones

Calorie restriction (CR) is a common approach to inducing negative energy balance. Recently, time-restricted feeding (TRF), which involves consuming food within specific time windows during a 24-h day, has become popular owing to its relative ease of practice and potential to aid in achieving and maintaining a negative energy balance. TRF can be implemented intentionally with CR, or TRF might induce CR simply because of the time restriction. This review focuses on summarizing our current knowledge on how TRF and continuous CR affect gut peptides that influence satiety. Based on peer-reviewed studies, in response to CR there is an increase in the orexigenic hormone ghrelin and a reduction in fasting leptin and insulin. There is likely a reduction in glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and cholecystokinin (CCK), albeit the evidence for this is weak. After TRF, unlike CR, fasting ghrelin decreased in some TRF studies, whereas it showed no change in several others. Further, a reduction in fasting leptin, insulin, and GLP-1 has been observed. In conclusion, when other determinants of food intake are held equal, the peripheral satiety systems appear to be somewhat similarly affected by CR and TRF with regard to leptin, insulin, and GLP-1. But unlike CR, TRF did not appear to robustly increase ghrelin, suggesting different influences on appetite with a potential decrease of hunger after TRF when compared with CR. However, there are several established and novel gut peptides that have not been measured within the context of CR and TRF, and studies that have evaluated effects of TRF are often short-term, with nonuniform study designs and highly varying temporal eating patterns. More evidence and studies addressing these aspects are needed to draw definitive conclusions.

The therapeutic potential of GLP-1 receptor biased agonism

Glucagon-like peptide-1 (GLP-1) receptor agonists are effective treatments for type 2 diabetes as they stimulate insulin release and promote weight loss through appetite suppression. Their main side effect is nausea. All approved GLP-1 agonists are full agonists across multiple signalling pathways. However, selective engagement with specific intracellular effectors, or biased agonism, has been touted as a means to improve GLP-1 agonists therapeutic efficacy. In this review, I critically examine how GLP-1 receptor-mediated intracellular signalling is linked to physiological responses and discuss the implications of recent studies investigating the metabolic effects of biased GLP-1 agonists. Overall, there is little conclusive evidence that beneficial and adverse effects of GLP-1 agonists are attributable to distinct, nonoverlapping signalling pathways. Instead, G protein-biased GLP-1 agonists appear to achieve enhanced anti-hyperglycaemic efficacy by avoiding GLP-1 receptor desensitisation and downregulation, partly via reduced β-arrestin recruitment. This effect seemingly applies more to insulin release than to appetite regulation and nausea, possible reasons for which are discussed. At present, most evidence derives from cellular and animal studies, and more human data are required to determine whether this approach represents a genuine therapeutic advance. LINKED ARTICLES: This article is part of a themed issue on GLP1 receptor ligands (BJP 75th Anniversary). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.4/issuetoc.

Liraglutide, a glucagon-like peptide 1 receptor agonist, exerts analgesic, anti-inflammatory and anti-degradative actions in osteoarthritis

Osteoarthritis (OA) is a common disabling disease worldwide, with no effective and safe disease-modifying drugs (DMOAD) in the market. However, studies suggest that drugs, such as liraglutide, which possess strong potential in decreasing low-grade systemic inflammation may be effective in treating OA. Therefore, the aim of this study was to examine the anti-inflammatory, analgesic, and anti-degradative effects in OA using in vitro and in vivo experiments. The results showed that intra-articular injection of liraglutide alleviated pain-related behavior in in vivo sodium monoiodoacetate OA mouse model, which was probably driven by the GLP-1R-mediated anti-inflammatory activity of liraglutide. Moreover, liraglutide treatment significantly decreased IL-6, PGE2 and nitric oxide secretion, and the expression of inflammatory genes in vitro in chondrocytes and macrophages in a dose-dependent manner. Additionally, liraglutide shifted polarized macrophage phenotype in vitro from the pro-inflammatory M1 phenotype to the M2 anti-inflammatory phenotype. Furthermore, liraglutide exerted anti-catabolic activity by significantly decreasing the activities of metalloproteinases and aggrecanases, a family of catabolic enzymes involved in cartilage breakdown in vitro. Overall, the findings of this study showed that liraglutide ameliorated OA-associated pain, possess anti-inflammatory and analgesic properties, and could constitute a novel therapeutic candidate for OA treatment.

Trends in Antidiabetic Drug Discovery: FDA Approved Drugs, New Drugs in Clinical Trials and Global Sales

Type 2 diabetes mellitus (T2DM) continues to be a substantial medical problem due to its increasing global prevalence and because chronic hyperglycemic states are closely linked with obesity, liver disease and several cardiovascular diseases. Since the early discovery of insulin, numerous antihyperglycemic drug therapies to treat diabetes have been approved, and also discontinued, by the United States Food and Drug Administration (FDA). To provide an up-to-date account of the current trends of antidiabetic pharmaceuticals, this review offers a comprehensive analysis of the main classes of antihyperglycemic compounds and their mechanisms: insulin types, biguanides, sulfonylureas, meglitinides (glinides), alpha-glucosidase inhibitors (AGIs), thiazolidinediones (TZD), incretin-dependent therapies, sodium-glucose cotransporter type 2 (SGLT2) inhibitors and combinations thereof. The number of therapeutic alternatives to treat T2DM are increasing and now there are nearly 60 drugs approved by the FDA. Beyond this there are nearly 100 additional antidiabetic agents being evaluated in clinical trials. In addition to the standard treatments of insulin therapy and metformin, there are new drug combinations, e.g., containing metformin, SGLT2 inhibitors and dipeptidyl peptidase-4 (DPP4) inhibitors, that have gained substantial use during the last decade. Furthermore, there are several interesting alternatives, such as lobeglitazone, efpeglenatide and tirzepatide, in ongoing clinical trials. Modern drugs, such as glucagon-like peptide-1 (GLP-1) receptor agonists, DPP4 inhibitors and SGLT2 inhibitors have gained popularity on the pharmaceutical market, while less expensive over the counter alternatives are increasing in developing economies. The large heterogeneity of T2DM is also creating a push towards more personalized and accessible treatments. We describe several interesting alternatives in ongoing clinical trials, which may help to achieve this in the near future.

Effect of GLP-1R rs2254336 and rs3765467 polymorphisms on gastrointestinal adverse reactions in type 2 diabetes patients treated with liraglutide

PURPOSE

Gastrointestinal adverse reactions (GIARs) to liraglutide exhibit significant individual differences in type 2 diabetes. This study investigated the association between glucagon-like peptide-1 receptor (GLP-1R) single-nucleotide polymorphisms (SNPs) and GIARs.

METHODS

Adverse events of liraglutide were observed in 376 T2DM patients. Seven tag SNPs at GLP-1R were sequenced in 152 participants. The influencing factors of GIARs and the genetic model of tag SNPs were examined by logistic regression analysis. The relationship between the tag SNPs and GIARs was determined by the chi-square test and cochran-armitage trend test. Multifactor dimensionality reduction (MDR) analysis was used to explore interactive analysis in GIARs risk.

RESULTS

Twenty-nine percent of subjects had side effects, mainly GIARs. Nausea was the most common GIARs. Compared with males, females were more likely to develop GIARs (P = 0.043, OR = 1.895, 95% CI: 1.021-3.517). The T allele at GLP-1R rs2254336 (P = 0.028) and the A allele at GLP-1R rs3765467 (P = 0.007) were associated with GIARs of liraglutide. As the number of rs2254336 T alleles (P = 0.014) or rs3765467 A alleles (P = 0.008) increased, the subjects tended to develop GIARs. MDR analysis identified that there were no significant interactions among rs2254336, rs3765467 and sex.

CONCLUSION

Our results suggest that female sex, the T allele at GLP-1R rs2254336 and the A allele at GLP-1R rs3765467 could be predictors of GIARs with liraglutide in T2DM patients.

Glucagon-Like Peptide-1 Agonist Exendin-4 Facilitates the Extinction of Cocaine-Induced Condition Place Preference

Accumulating studies suggest that the glucagon-like peptide-1 receptor agonist exendin-4 (Ex4) and toll-like receptor 4 (TLR4) play a pivotal role in the maladaptive behavior of cocaine. However, few studies have assessed whether Ex4 can facilitate the extinction of drug-associated behavior and attenuate the reinstatement of cocaine-induced condition place preference (CPP) in mice. The main objective of the present study was to evaluate Ex4's ability to regulate the extinction and reinstatement of cocaine-induced CPP. C57BL/6 mice were conditioned to either cocaine (20 mg/kg) or an equivalent volume of saline to establish a cocaine-mediated CPP paradigm. To investigate the potential effects of Ex4 on extinction, animals received an intraperitoneal injection of Ex4 either immediately or 6 h after each extinction or only on the test day. The persistence of extinction was measured using the reinstatement paradigm evoked by 10 mg/kg of cocaine. To explore the possible impacts of Ex4 and neuroinflammation on cocaine, the expression levels of TLR4 within the hippocampus was detected using western blotting. As a result, we found that systemic administration of Ex4 immediately after each extinction training, instead of 6 h after each extinction and on the day of extinction test, was capable of facilitating extinction in the confined or non-confined CPP extinction paradigms and blocking the cocaine-primed reinstatement of cocaine-induced CPP. Additionally, we also observed that Ex4 was competent to alleviate TLR4 signaling that has been up-regulated by cocaine. Altogether, our findings indicated that the combination of Ex4 with daily extinction training was sufficient to facilitate extinction of the conditioned behavior, attenuate reinstatement of cocaine-induced CPP and inhibit TLR4 signaling. Thus, Ex4 deserves further investigation as a potential intervention for the treatment of cocaine use disorder.

Effects of Glucagon-Like Peptide-1 Receptor Agonist Exendin-4 on the Reinstatement of Cocaine-Mediated Conditioned Place Preference in Mice

A high percentage of relapse to compulsive cocaine-taking and cocaine-seeking behaviors following abstinence constitutes a major obstacle to the clinical treatment of cocaine addiction. Thus, there is a substantial need to develop effective pharmacotherapies for the prevention of cocaine relapse. The reinstatement paradigm is known as the most commonly used animal model to study relapse in abstinent human addicts. The primary aim of this study is to investigate the potential effects of systemic administration of glucagon-like peptide-1 receptor agonist (GLP-1RA) exendin-4 (Ex4) on the cocaine- and stress-triggered reinstatement of cocaine-induced conditioned place preference (CPP) in male C57BL/6J mice. The biased CPP paradigm was induced by alternating administration of saline and cocaine (20 mg/kg), followed by extinction training and then reinstatement by either a cocaine prime (10 mg/kg) or exposure to swimming on the reinstatement test day. To examine the effects of Ex4 on the reinstatement, Ex4 was systemically administered 1 h after the daily extinction session. Additionally, we also explored the associated molecular basis of the behavioral effects of Ex4. The expression of nuclear factor κβ (NF-κβ) in the nucleus accumbens (NAc) was detected using Western blotting. As a result, all animals that were treated with cocaine during the conditioning period successfully acquired CPP, and their CPP response was extinguished after 8 extinction sessions. Furthermore, the animals that were exposed to cocaine or swimming on the reinstatement day showed a significant reinstatement of CPP. Interestingly, systemic pretreatment with Ex4 was sufficient to attenuate cocaine- and stress-primed reinstatement of cocaine-induced CPP. Additionally, the expression of NF-κβ, which was upregulated by cocaine, was normalized by Ex4 in the cocaine-experienced mice. Altogether, our study reveals the novel effect of Ex4 on the reinstatement of cocaine-induced CPP and suggests that GLP-1R agonists appear to be highly promising drugs in the treatment of cocaine use disorder.

Liraglutide Activates Type 2 Deiodinase and Enhances β3-Adrenergic-Induced Thermogenesis in Mouse Adipose Tissue

Aims

Liraglutide is a long-acting glucagon-like peptide 1 (GLP-1) receptor agonist used as an anti-hyperglycemic agent in type 2 diabetes treatment and recently approved for obesity management. Weight loss is attributed to appetite suppression, but therapy may also increase energy expenditure. To further investigate the effect of GLP-1 signaling in thermogenic fat, we assessed adipose tissue oxygen consumption and type 2 deiodinase (D2) activity in mice treated with liraglutide, both basally and after β3-adrenergic treatment.

Methods

Male C57BL/6J mice were randomly assigned to receive liraglutide (400 μg/kg, n=12) or vehicle (n=12). After 16 days, mice in each group were co-treated with the selective β3-adrenergic agonist CL316,243 (1 mg/kg, n=6) or vehicle (n=6) for 5 days. Adipose tissue depots were assessed for gene and protein expression, oxygen consumption, and D2 activity.

Results

Liraglutide increased interscapular brown adipose tissue (iBAT) oxygen consumption and enhanced β3-adrenergic-induced oxygen consumption in iBAT and inguinal white adipose tissue (ingWAT). These effects were accompanied by upregulation of UCP-1 protein levels in iBAT and ingWAT. Notably, liraglutide increased D2 activity without significantly upregulating its mRNA levels in iBAT and exhibited additive effects to β3-adrenergic stimulation in inducing D2 activity in ingWAT.

Conclusions

Liraglutide exhibits additive effects to those of β3-adrenergic stimulation in thermogenic fat and increases D2 activity in BAT, implying that it may activate this adipose tissue depot by increasing intracellular thyroid activation, adding to the currently known mechanisms of GLP-1A-induced weight loss.

Tirzepatide: A Novel, Once-weekly Dual GIP and GLP-1 Receptor Agonist for the Treatment of Type 2 Diabetes

Gastrointestinal hormones are currently used to treat type 2 diabetes mellitus (T2D). Incretin preparations with gastric inhibitory polypeptide (GIP) activity or glucagon-like peptide-1 (GLP-1) provide new means for controlling blood glucose levels, body weight, and lipid metabolism. GIP, an incretin, has not been used due to lack of promising action against diabetes. However, recent studies have shown that GIP has an important effect on glucagon and insulin secretion under normoglycaemic conditions. Co-existence of GIP with GLP-1 and glucagon signalling leads to a stronger effect than that of GLP-1 stimulation alone. The development of a GIP/GLP-1R unimolecular dual agonist with affinity for both GIP and GLP-1 receptors is under investigation, and the drug is expected to be clinically available in the near future. Tirzepatide, a GIP/GLP-1R unimolecular dual agonist, regulates metabolism via both peripheral organs and the central nervous system. The SURPASS phase III clinical trials conducted for tirzepatide comprise 10 clinical trials, including five global trials and the global SURPASS-CVOT trial, with >13,000 patients with T2D (ClinicalTrials.gov Identifier: NCT04255433). The clinical application of tirzepatide as a therapy for T2D may provide new insights into diabetic conditions and help clarify the role of GIP in its pathogenesis.

The potential of GLP-1 receptor agonists in type 2 diabetes and chronic kidney disease: from randomised trials to clinical practice

Chronic kidney disease (CKD) affects around 10% of the global population and is most often caused by diabetes. Diabetes with CKD (diabetic kidney disease, DKD) is a progressive condition that may cause kidney failure and which contributes significantly to the excess morbidity and mortality in these patients. DKD is treated with direct disease-targeting therapies like blockers of the renin-angiotensin system, sodium-glucose cotransporter-2 (SGLT-2) inhibitors and non-steroidal mineralocorticoid receptor antagonists as well as indirect therapies impacting hyperglycaemia, dyslipidaemia, obesity and hypertension, which all together reduce disease progression. While no glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are currently indicated to improve kidney outcomes, accumulating evidence from cardiovascular outcomes trials (CVOTs) corroborates a kidney-protective effect in people with T2D and CKD, and GLP-1 RAs are now mentioned in international treatment guidelines for type 2 diabetes (T2D) with CKD. GLP-1 RAs are indicated to improve glycaemia in people with T2D; certain GLP-1 RAs are also approved for weight management and to reduce cardiovascular risk in T2D. Ongoing pivotal trials are assessing additional indications, including T2D with CKD. In this article, we review and discuss kidney outcomes from a multitude of completed clinical trials as well as real-world evidence and ongoing clinical trials.

Gut microbiota-motility interregulation: insights from in vivo, ex vivo and in silico studies

The human gastrointestinal tract is home to trillions of microbes. Gut microbial communities have a significant regulatory role in the intestinal physiology, such as gut motility. Microbial effect on gut motility is often evoked by bioactive molecules from various sources, including microbial break down of carbohydrates, fibers or proteins. In turn, gut motility regulates the colonization within the microbial ecosystem. However, the underlying mechanisms of such regulation remain obscure. Deciphering the inter-regulatory mechanisms of the microbiota and bowel function is crucial for the prevention and treatment of gut dysmotility, a comorbidity associated with many diseases. In this review, we present an overview of the current knowledge on the impact of gut microbiota and its products on bowel motility. We discuss the currently available techniques employed to assess the changes in the intestinal motility. Further, we highlight the open challenges, and incorporate biophysical elements of microbes-motility interplay, in an attempt to lay the foundation for describing long-term impacts of microbial metabolite-induced changes in gut motility.

Effect of metformin versus metformin plus liraglutide on gonadal and metabolic profiles in overweight patients with polycystic ovary syndrome

OBJECTIVE

To observe the effect of metformin (MET) monotherapy versus MET plus liraglutide (LIRA) on gonadal and metabolic profiles in overweight patients with polycystic ovary syndrome (PCOS).

METHODS

Sixty overweight patients with PCOS were recruited from January 2021 to January 2022 in Shengjing Hospital of China Medical University and were randomly assigned to the MET or combination (COM) group to receive 12 weeks of MET monotherapy or MET plus LIRA therapy. Anthropometric measurements, menstrual cycle changes, gonadal profiles, and oral glucose tolerance tests (OGTT) were conducted at baseline and after the 12-week treatment.

RESULTS

Fifty-two subjects completed the trial while eight were lost during the follow-up. Both MET and COM improved menstrual cycles, anthropometric parameters, and glucose metabolism after the 12-week treatment; however, there was no statistical difference between the two groups. MET plus LIRA therapy improved hyperandrogenemia, including TT (total testosterone), SHBG (sex hormone binding globulin) and FAI (free androgen index), whereas MET monotherapy only improved SHBG and FAI when compared with baseline. Furthermore, both MET monotherapy and MET plus LIRA therapy improved E2 (estradiol) while only MET plus LIRA therapy improved LH (luteinizing hormone), FSH (follicle stimulating hormone) and Prog (progesterone) more effectively than baseline. Additionally, MET plus LIRA therapy may improve TT, SHBG, FAI, LH and Prog more effectively than MET monotherapy; however, there were no significant differences on E2, FSH and LH/FSH between the two groups.

CONCLUSIONS

In overweight patients with PCOS, both MET monotherapy and MET plus LIRA therapy improved glucose metabolism and relieved insulin resistance (IR). Additionally, MET plus LIRA therapy was more effective than MET monotherapy in improving reproductive abnormalities and hyperandrogenemia, potentially by modulating the hypothalamic-pituitary-ovarian axis.

Antiobesity therapeutics with complementary dual-agonist activities at glucagon and glucagon-like peptide 1 receptors

AIM

To develop more effective and long-lasting antiobesity and antidiabetic therapeutics by employing novel chemical modifications of glucagon-like peptide-1 receptor (GLP-1R) agonists.

METHODS

We constructed novel unimolecular dual agonists of GLP-1R and glucagon receptor prepared by linking sEx-4 and native glucagon (GCG) via lysine or triazole [sEx4-GCG(K) and sEx4-GCG(T), respectively] and evaluated their antiobesity and antidiabetic efficacy in the diabetic and obese mouse model.

RESULTS

Both sEx4-GCG(K) and sEx4-GCG(T) showed the beneficial metabolic effects of GLP-1 and glucagon: they promoted weight loss and ameliorated insulin resistance and hepatic steatosis. They also increased thermogenesis in brown adipose tissue, and lipolysis and β-oxidation in white adipose tissue, with concomitant suppression of lipogenesis. Furthermore, both dual agonists activated the 5'-AMP-activated protein kinase signalling pathway and prevented palmitate-induced oxidative stress in skeletal muscle cells.

CONCLUSION

Through their complementary dual agonism, sEx4-GCG(T) and sEx4-GCG(K) induce more marked weight loss and metabolic improvements than conventional agonists, and could be developed as novel therapeutic agents for the treatment of obesity and associated metabolic disorders in humans.

Real world effectiveness of subcutaneous semaglutide in type 2 diabetes: A retrospective, cohort study (Sema-MiDiab01)

INTRODUCTION

Aim of the present study was to evaluate the real-world impact of once-weekly (OW) subcutaneous semaglutide on different end-points indicative of metabolic control, cardiovascular risk factors, and beta-cell function in type 2 diabetes (T2D).

METHODS

This was a retrospective, observational study conducted in 5 diabetes clinics in Italy. Changes in HbA1c, fasting blood glucose (FBG), body weight, blood pressure, lipid profile, renal function, and beta-cell function (HOMA-B) during 12 months were evaluated.

RESULTS

Overall, 594 patients (97% GLP-1RA naïve) were identified (mean age 63.9 ± 9.5 years, 58.7% men, diabetes duration 11.4 ± 8.0 years). After 6 months of treatment with OW semaglutide, HbA1c levels were reduced by 0.90%, FBG by 26 mg/dl, and body weight by 3.43 kg. Systolic blood pressure, total and LDL-cholesterol significantly improved. Benefits were sustained at 12 months. Renal safety was documented. HOMA-B increased from 40.2% to 57.8% after 6 months (p<0.0001).

DISCUSSION

The study highlighted benefits of semaglutide on metabolic control, multiple CV risk factors, and renal safety in the real-world. Semaglutide seems to be an advisable option for preservation of β-cell function and early evidence suggests it might have a role in modifying insulin resistance (HOMA-IR), the pathogenetic basis of prediabetes and T2D.

Difference in Gastrointestinal Risk Associated with Use of GLP-1 Receptor Agonists: A Real-World Pharmacovigilance Study

BACKGROUND

Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) are promising weight-loss drugs, but real-world data concerning the liability of GLP-1RAs in gastrointestinal safety are lacking. We examined the differences in gastrointestinal safety between semaglutide and liraglutide.

MATERIALS AND METHODS

We used the US Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS) database and retrieved data during the first three years of semaglutide and liraglutide approved by the FDA. Thirteen main gastrointestinal adverse drug reactions (GADRs) were evaluated. Patient demographics, treatment information, and outcome of events were summarized. Disproportionality analyses were conducted by estimating the reporting odds ratios (RORs) and 95% confidence intervals (CIs).

RESULTS

In the reported cases of semaglutide (n = 2047) and liraglutide (n = 4175), semaglutide had a higher pooled ROR and later pooled time-to-onset median of GADRs compared with those of liraglutide (5.53, 95% CI 5.23-5.85 vs 3.95, 95% CI 3.81-4.10; 7 days, Q1-Q3: 0-48 vs 4 days, Q1-Q3: 0-34.5). The thirteen GADRs associated with these two GLP-1RAs showed a significant difference in the profile of reporting risk and time-to-onset.

CONCLUSION

GLP-1RAs produce a spectrum of distinct classes of GADRs. The individual properties of GADRs between semaglutide and liraglutide might enable incretin-based treatment of obesity to be "tailored" to the needs of each patient.

Emerging therapies: The potential roles SGLT2 inhibitors, GLP1 agonists, and ARNI therapy for ARNI pulmonary hypertension

Pulmonary hypertension (PH) is a highly morbid condition. PH due to left heart disease (PH-LHD) has no specific therapies and pulmonary arterial hypertension (PAH) has substantial residual risk despite several approved therapies. Multiple lines of experimental evidence link metabolic dysfunction to the pathogenesis and outcomes in PH-LHD and PAH, and novel metabolic agents hold promise to improve outcomes in these populations. The antidiabetic sodium-glucose cotransporter 2 (SGLT2) inhibitors and glucagon-like peptide-1 (GLP1) agonists targeting metabolic dysfunction and improve outcomes in patients with LHD but have not been tested specifically in patients with PH. The angiotensin receptor/neprilysin inhibitors (ARNIs) produce significant improvements in cardiac hemodynamics and may improve metabolic dysfunction that could benefit the pulmonary circulation and right ventricle function. On the basis of promising preclinical work with these medications and clinical rationale, we explore the potential of SGLT2 inhibitors, GLP1 agonists, and ARNIs as therapies for both PH-LHD and PAH.

Preventing Oxidative Stress in the Liver: An Opportunity for GLP-1 and/or PASK

The liver’s high metabolic activity and detoxification functions generate reactive oxygen species, mainly through oxidative phosphorylation in the mitochondria of hepatocytes. In contrast, it also has a potent antioxidant mechanism for counterbalancing the oxidant’s effect and relieving oxidative stress. PAS kinase (PASK) is a serine/threonine kinase containing an N-terminal Per-Arnt-Sim (PAS) domain, able to detect redox state. During fasting/feeding changes, PASK regulates the expression and activation of critical liver proteins involved in carbohydrate and lipid metabolism and mitochondrial biogenesis. Interestingly, the functional inactivation of PASK prevents the development of a high-fat diet (HFD)-induced obesity and diabetes. In addition, PASK deficiency alters the activity of other nutrient sensors, such as the AMP-activated protein kinase (AMPK) and the mammalian target of rapamycin (mTOR). In addition to the expression and subcellular localization of nicotinamide-dependent histone deacetylases (SIRTs). This review focuses on the relationship between oxidative stress, PASK, and other nutrient sensors, updating the limited knowledge on the role of PASK in the antioxidant response. We also comment on glucagon-like peptide 1 (GLP-1) and its collaboration with PASK in preventing the damage associated with hepatic oxidative stress. The current knowledge would suggest that PASK inhibition and/or exendin-4 treatment, especially under fasting conditions, could ameliorate disorders associated with excess oxidative stress.

Efficacy and safety of semaglutide in glycemic control, body weight management, lipid profiles and other biomarkers among obese type 2 diabetes patients initiated or switched to semaglutide from other GLP-1 receptor agonists

Purpose

Evidence of the efficacy and safety of semaglutide among patients with type 2 diabetes who were initiated on or were switched to semaglutide from other GLP-1 RAs remains limited. The objective of this study was to investigate the short-term effects of switching to semaglutide from other GLP-1 RAs.

Methods

This retrospective cohort study evaluated patients with type 2 diabetes who were initiated on or were switched to semaglutide due to poor diabetes control with other GLP-1 RAs or other medications, or obesity. HbA1c, body weight, serum creatinine, serum uric acid, parameters of lipid metabolism, and parameters of liver function were measured before and 6 months after administration of semaglutide.

Results

A total of 50 patients were registered in the study. After switching to semaglutide (n = 43), HbA1c and body weight significantly decreased (p < 0.01, p < 0.01), respectively. The same findings were observed in semaglutide-naïve patients (p = 0.04, p < 0.02) (n = 7). Serum uric acid, total cholesterol, triglycerides, and urinary albumin-creatinine ratio decreased significantly as well (p = 0.04, p = 0.04, p = 0.02, p = 0.04), whereas serum creatinine did not change significantly (p = 0.51).

Conclusions

Semaglutide showed excellent efficacy, even in patients switched from other GLP-1 RAs. Semaglutide appears to be a promising agent for blood glucose and body weight control in obese type 2 diabetes mellitus patients and could be more potent in treating type 2 diabetes than existing GLP-1 RAs.

Diabetes, Drug Treatment, and Mortality in COVID-19: A Multinational Retrospective Cohort Study

Patients with type 2 diabetes mellitus (T2DM) are at increased risk of severe coronavirus disease 2019 (COVID-19) outcomes possibly because of dysregulated inflammatory responses. Glucose-regulating medications, such as glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors, and pioglitazone, are known to have anti-inflammatory effects that may improve outcomes in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. In a multinational retrospective cohort study, we used the TriNetX COVID-19 Research Network of 56 large health care organizations to examine these medications in relation to the incidence of hospital admissions, respiratory complications, and mortality within 28 days after a COVID-19 diagnosis. After matching for age, sex, race, ethnicity, BMI, and significant comorbidities, use of GLP-1R agonists and/or pioglitazone was associated with significant reductions in hospital admissions (GLP-1R: 15.7% vs. 23.5%, risk ratio [RR] 0.67 [95% CI 0.57-0.79; P < 0.001]; pioglitazone: 20.0% vs. 28.2%; RR 0.71 [95% CI 0.54-0.93; P = 0.01]). Use of GLP-1R agonists was also associated with reductions in respiratory complications (15.3% vs. 24.9%, RR 0.62 [95% CI 0.52-0.73]; P < 0.001) and incidence of mortality (1.9% vs. 3.3%, RR 0.58 [95% CI 0.35-0.97]; P = 0.04). Use of DPP-4 inhibitors was associated with a reduction in respiratory complications (24.0% vs. 29.2%, RR 0.82 [95% CI 0.74-0.90]; P < 0.001), and continued use of DPP-4 inhibitors after hospitalization was associated with a decrease in mortality compared with those who discontinued use (9% vs. 19%, RR 0.45 [95% CI 0.28-0.72]; P < 0.001). In conclusion, use of glucose-regulating medications, such as GLP-1R agonists, DPP-4 inhibitors, or pioglitazone, may improve COVID-19 outcomes for patients with T2DM; randomized clinical trials are needed to further investigate this possibility.

Akkermansia muciniphila – obiecujący kandydat na probiotyk nowej generacji

W ostatnich czasach można zaobserwować duży wzrost zainteresowania relacjami między człowiekiem a mikroorganizmami zasiedlającymi jego organizm. Licznie występują w oraz na ciele człowieka, a ich liczba przekracza liczbę komórek ludzkiego organizmu. Udoskonalenie technik badawczych pozwala lepiej zrozumieć molekularne podłoże tych oddziaływań, co być może pozwoli na wykorzystanie w terapiach tych mikroorganizmów, które korzystnie wpływają na organizm człowieka. W artykule podsumowano dotychczasową wiedzę na temat fizjologii licznie występującej w przewodzie pokarmowym bakterii Akkermansia muciniphila i jej wpływu na organizm gospodarza. Opisano właściwości A. muciniphila, jej funkcjonowanie w środowisku przewodu pokarmowego oraz relacje (zarówno antagonistyczne jak i symbiotyczne) z innymi tam bytującymi mikroorganizmami. Przedstawiono także mechanizmy oddziaływania A. muciniphila na barierę jelitową, układ immunologiczny oraz metabolizm energetyczny gospodarza. Ponadto opisano jej rolę w patogenezie i terapii chorób, w tym m.in. cukrzycy typu 2, nieswoistego zapalenia jelit, zaburzeń neurologicznych, astmy, a także jej wpływ na odpowiedź pacjenta na terapie przeciwnowotworowe oparte na działaniu układu odpornościowego. Duże zainteresowanie tą bakterią, a także przytoczone wyniki badań, w tym tych sprawdzających bezpieczeństwo jej stosowania, wskazują, że A. muciniphila może być obiecującym kandydatem na probiotyk nowej generacji. Niewątpliwie jednak przed dopuszczeniem A. muciniphila do powszechnego stosowania konieczne są dalsze badania z udziałem ludzi, a także wnikliwa ocena bezpieczeństwa jej stosowania.

Physicochemical, morpho-structural, and biological characterization of polysaccharides from three Polygonatum spp

Polygonatum species, including P. cyrtonema, P. kingianum, and P. sibiricum, are edible plants with medicinal purposes, which have long been consumed as food due to their high nutritional value. In this study, polysaccharides from P. cyrtonema (PCP), P. kingianum (PKP) and P. sibiricum (PSP) were obtained, and their physicochemical properties and in vitro biological activities were investigated. Our results demonstrated that PCP, PKP, and PSP consist of major fructose and minor glucose, galacturonic acid, and galactose in different molar ratios with the molecular weights of 8.5 × 10³ Da, 8.7 × 10³ Da, and 1.0 × 10⁴ Da, respectively. The three polysaccharides had triple-helical structures with β-d-Fruf, α-d-Glcp, α-d-Galp sugar residues, and an O-acetyl group, and displayed peak-shaped structures in different sizes. They also exhibited thermal, shear-thinning behavior and viscoelastic properties, and PCP presented the highest viscoelasticity. Moreover, they exerted strong free radical-scavenging abilities, and significant reducing capacity. PCP was the strongest, followed by PSP and then PKP. They significantly promoted the polarization of the M1 macrophage, with the effect of PCP ranking first. All three had similar effects on GLP-1 secretion. It is, therefore, necessary to identify the various roles of these three Polygonatum polysaccharides as functional agents based on their bioactivities and physicochemical properties.

Three Polygonatum polysaccharides with different physicochemical properties exert distinct effects on free radical-scavenging abilities and the promotion of M1 macrophage polarization, while they have similar effects on GLP-1 secretion.

Incretins in the Therapy of Diabetic Kidney Disease

Diabetic kidney disease is a microvascular complication that occurs in patients with diabetes. It is strongly associated with increased risk of kidney replacement therapy and all-cause mortality. Incretins are peptide hormones derived from the gastrointestinal tract, that besides causing enhancement of insulin secretion after oral glucose intake, participate in many other metabolic processes. Antidiabetic drug classes, such as dipeptidyl peptidase 4 inhibitors and glucagon-like peptide receptor agonists, which way of action is based on incretins facility, not only show glucose-lowering properties but also have nephroprotective functions. The aim of this article is to present the latest information about incretin-based therapy and its influence on diabetic kidney disease appearance and progression, point its potential mechanisms of kidney protection and focus on future therapeutic possibilities bound with these two antidiabetic drug classes.

Effect of beinaglutide treatment on weight loss in Chinese patients with type 2 diabetes mellitus and overweight/obesity

OBJECTIVE

To evaluate the effect of beinaglutide on weight loss and plasma protein patterns of inflammation/obesity relevant cytokines and biomarkers.

METHODS

This study involved 36 adult patients with a body mass index (BMI) of ≥ 24 kg/m2 and T2DM. Beinaglutide was administered for three months. Changes in body weight, fasting plasma glucose (FPG) level, 2 h postprandial plasma glucose (2h-PG) level, glycosylated hemoglobin (HbA1c) level, BMI and visceral and subcutaneous fat areas were measured at baseline and after three months of treatment. In addition, relevant inflammation/obesity cytokines and biomarkers were measured.

RESULTS

After three months, beinaglutide treatment led to significant changes, including in body weight, BMI, FPG level, HbA1c level, visceral and subcutaneous fat areas. In addition, serpin E1, leptin, C-reaction protein (CRP) and tumor necrosis factor-α (TNF-α) also decreased significantly. The plasma protein concentrations of CRP (Log2 transformed) were found to be positively correlated with the percentage of weight loss (R = 0.514 and p-value = 0.021).

CONCLUSION

Beinaglutide treatment resulted in weight loss, plasma glucose control and anti-inflammatory effects in patients with T2DM and overweight/obesity.

Role of Renal Sympathetic Nerves in GLP-1 (Glucagon-Like Peptide-1) Receptor Agonist Exendin-4-Mediated Diuresis and Natriuresis in Diet-Induced Obese Rats

Background

The gut‐derived hormone GLP‐1 (glucagon‐like peptide‐1) exerts beneficial effects against established risk factors for chronic kidney disease. GLP‐1 influences renal function by stimulating diuresis and natriuresis and thus lowering arterial blood pressure. The role of the sympathetic nervous system has been implicated as an important link between obesity with elevated arterial pressure and chronic kidney disease. The primary aim of this study was to determine the contribution of renal sympathetic nerves on intrapelvic GLP‐1‐mediated diuresis and natriuresis in high‐fat diet (HFD)‐induced obese rats.

Methods and Results

Obesity was induced in rats by HFD for 12 weeks, followed by either surgical bilateral renal denervation or chronic subcutaneous endopeptidase neprilysin inhibition by sacubitril for a week. Diuretic and natriuretic responses to intrapelvic administration of the GLP‐1R (GLP‐1 receptor) agonist exendin‐4 were monitored in anesthetized control and HFD rats. Renal GLP‐1R expression and neprilysin expression and activity were measured. The effects of norepinephrine on the expression of GLP‐1R and neprilysin in kidney epithelial LLC‐PK1 cells were also examined. We found that diuretic and natriuretic responses to exendin‐4 were significantly reduced in the HFD obese rats compared with the control rats (cumulative urine flow at 40 minutes, 387±32 versus 650±65 µL/gkw; cumulative sodium excretion at 40 minutes, 42±5 versus 75±10 µEq/gkw, P<0.05). These responses in the HFD rats were restored after ablation of renal nerves (cumulative urine flow at 40 minutes, 625±62 versus 387±32 µL/gkw; cumulative sodium excretion at 40 minutes, 70±9 versus 42±5 µEq/gkw, P<0.05). Renal denervation induced significant reductions in arterial pressure and heart rate responses to intrapelvic GLP‐1 in the HFD rats. Renal denervation also significantly increased the GLP‐1R expression and reduced neprilysin expression and activity in renal tissues from the HFD rats. Chronic subcutaneous neprilysin inhibition by sacubitril increased GLP‐1–induced diuretic and natriuretic effects in the HFD rats. Finally, exposure of the renal epithelial cells to norepinephrine in vitro led to downregulation of GLP‐1R expression but upregulation of neprilysin expression and activity.

Conclusions

These results suggest that renal sympathetic nerve activation contributes to the blunted diuretic and natriuretic effects of GLP‐1 in HFD obese rats. This study provides significant novel insight into the potential renal nerve–neprilysin–GLP‐1 pathway involved in renal dysfunction during obesity that leads to hypertension.

Exendin(9-39)NH2 : Recommendations for clinical use based on a systematic literature review

AIM

To present an overview of exendin(9-39)NH₂ usage as a scientific tool in humans and provide recommendations for dosage and infusion regimes.

METHODS

We systematically searched the literature on exendin(9-39)NH₂ and included for review 44 clinical studies reporting use of exendin(9-39)NH₂ in humans.

RESULTS

Exendin(9-39)NH₂ binds to the orthosteric binding site of the glucagon-like peptide-1 (GLP-1) receptor with high affinity. The plasma elimination half-life of exendin(9-39)NH₂ after intravenous administration is ~30 minutes, requiring ~2.5 hours of constant infusion before steady-state plasma concentrations can be expected. Studies utilizing infusions with exendin(9-39)NH₂ in humans have applied varying regimens (priming with a bolus or constant infusion) and dosages (continuous infusion rate range 30-900 pmol/kg/min) with subsequent differences in effects. Administration of exendin(9-39)NH₂ in healthy individuals, patients with diabetes, obese patients, and patients who have undergone bariatric surgery significantly increases fasting and postprandial levels of glucose and glucagon, but has inconsistent effects on circulating concentrations of insulin and C-peptide, gastric emptying, appetite sensations, and food intake. Importantly, exendin(9-39)NH₂ induces secretion of all L cell products (ie, in addition to GLP-1, also peptide YY, glucagon-like peptide-2, oxyntomodulin, and glicentin) complicating use of exendin(9-39)NH₂ as a tool to study the isolated effect of GLP-1.

CONCLUSIONS

Exendin(9-39)NH₂ is selective for the GLP-1 receptor, with numerous and complex whole-body effects. To obtain GLP-1 receptor blockade in humans, we recommend an initial high-dose infusion, followed by a continuous infusion rate aiming at a ratio of exendin(9-39)NH₂ to GLP-1 of 2000:1. Highlights Exendin(9-39)NH₂ is a competitive antagonist of the human GLP-1 receptor. Exendin(9-39)NH₂ has been used as a tool to delineate human GLP-1 physiology since 1998. Exendin(9-39)NH₂ induces secretion of GLP-1 and other L cell products. Reported effects of exendin(9-39)NH₂ on insulin levels and food intake are inconsistent. Here, we provide recommendations for the use of exendin(9-39)NH₂ in clinical studies.

Anti-TNFα treatment in Crohn's disease: Impact on hepatic steatosis, gut-derived hormones and metabolic status

BACKGROUND AND AIMS

An association between Crohn's disease (CD) and hepatic steatosis has been reported. However, the underlying mechanisms of steatosis progression in CD are not clear. Among the most effective CD treatments are agents that inhibit Tumor-Necrosis-Factor (TNF) activity, yet it is unclear why anti-TNFα agents would affect steatosis in CD. Recent studies suggest that microbiome can affect both, CD and steatosis pathogenesis. Therefore, we here analysed a potential relationship between anti-TNF treatment and hepatic steatosis in CD, focusing on the gut-liver axis.

METHODS

This cross-sectional study evaluated patients with established CD, with and without anti-TNFα treatment, analysing serum markers of liver injury, measurement of transient elastography, controlled attenuation parameter (CAP) and MRI for fat detection. Changes in lipid and metabolic profiles were assessed by serum and stool lipidomics and metabolimics. Additionally, we analysed gut microbiota composition and mediators of bile acid (BA) signalling via stool and serum analysis.

RESULTS

Patients on anti-TNFα treatment had less hepatic steatosis as assessed by CAP and MRI. Serum FGF19 levels were significantly higher in patients on anti-TNFα therapy and associate with reduced steatosis and increased bowel motility. Neutral lipids including triglycerides were reduced in the serum of patients on anti-TNF treatment. Bacteria involved in BA metabolism and FGF19 regulation, including Firmicutes, showed group-specific alterations with low levels in patients without anti-TNFα treatment. Low abundance of Firmicutes was associated with higher triglyceride levels.

CONCLUSIONS

Anti-TNFα treatment is associated with reduced steatosis, lower triglyceride levels, alterations in FXR-signalling (eg FGF19) and microbiota composition in CD.

Gut microbiota and its metabolites: Bridge of dietary nutrients and obesity-related diseases

While the incidence of obesity keeps increasing in both adults and children worldwide, obesity and its complications remain major threatens to human health. Over the past decades, accumulating evidence has demonstrated the importance of microorganisms and their metabolites in the pathogenesis of obesity and related diseases. There also is a significant body of evidence validating the efficacy of microbial based therapies for managing various diseases. In this review, we collected the key information pertinent to obesity-related bacteria, fermentation substrates and major metabolites generated by studies involving humans and/or mice. We then briefly described the possible molecular mechanisms by which microorganisms cause or inhibit obesity with a focus on microbial metabolites. Lastly, we summarized the advantages and disadvantages of the utilization of probiotics, plant extracts, and exercise in controlling obesity. We speculated that new targets and combined approaches (e.g. diet combined with exercise) could lead to more precise prevention and/or alleviation of obesity in future clinical research implications.

Effect of Bariatric Surgery on Metabolic Diseases and Underlying Mechanisms

Obesity is a highly prevalent public health concern, attributed to multifactorial causes and limited in treatment options. Several comorbidities are closely associated with obesity such as the development of type 2 diabetes mellitus (T2DM), cardiovascular and cerebrovascular diseases, and nonalcoholic fatty liver disease (NAFLD). Bariatric surgery, which can be delivered in multiple forms, has been remarked as an effective treatment to decrease the prevalence of obesity and its associated comorbidities. The different types of bariatric surgery create a variety of new pathways for food to metabolize in the body and truncate the stomach's caliber. As a result, only a small quantity of food is tolerated, and the body mass index noticeably decreases. This review describes the improvements of obesity and its comorbidities following bariatric surgery and their mechanism of improvement. Additionally, endocrine function improvements after bariatric surgery, which contributes to the patients' health improvement, are described, including the role of glucagon-like peptide-1 (GLP-1), fibroblast growth factors 19 and 21 (FGF-19, FGF-21), and pancreatic peptide YY (PYY). Lastly, some of the complications of bariatric surgery, including osteoporosis, iron deficiency/anemia, and diarrhea, as well as their potential mechanisms, are described.

Genome Mining-Based Discovery of Blenny Fish-Derived Peptides Targeting the Mouse κ-Opioid Receptor

Over the past years, peptides have attracted increasing interest for G protein-coupled receptor (GPCR) drug discovery and development. Peptides occupy a unique chemical space that is not easily accessible for small molecules and antibodies and provide advantages over these ligand classes such as lower toxicity and higher selectivity. The κ-opioid receptor (KOR) is a prototypic GPCR and an appealing therapeutic target for the development of safer and more effective analgesics. Recently, peptides have emerged as analgesic drug candidates with improved side effect profiles. We have previously identified plant-derived peptides, which activate KOR. Based on this precedent, here we relied on publicly available databases to discover novel KOR peptide ligands by genome mining. Using human preprodynorphin as a query, we identified blenny fish-derived peptides, referred to as blenniorphins, capable of binding to and activating KOR with nanomolar affinity and potency, respectively. Additionally, the blenniorphins altered β-arrestin-2 recruitment at the KOR. Our study demonstrates the utility of genome mining to identify peptide GPCR ligands with intriguing pharmacological properties and unveils the potential of blenny fishes as a source for novel KOR ligands.

A randomized controlled trial of the GLP-1 receptor agonist dulaglutide in primary polydipsia

BackgroundPrimary polydipsia, characterized by excessive fluid intake, carries the risk of water intoxication and hyponatremia, but treatment options are scarce. Glucagon-like peptide 1 (GLP-1) reduces appetite and food intake. In experimental models, GLP-1 has also been shown to play a role in thirst and drinking behavior. The aim of this trial was to investigate whether GLP-1 receptor agonists reduce fluid intake in patients with primary polydipsia.MethodsIn this randomized, double-blind, placebo-controlled, 3-week crossover trial, 34 patients with primary polydipsia received weekly dulaglutide (1.5 mg, Trulicity) in one treatment segment and placebo (0.9% sodium chloride) in the other. During the last treatment week, patients attended an 8-hour evaluation visit with free access to water. The primary endpoint was total fluid intake during the evaluation visits. Treatment effects were estimated using linear mixed-effects models. In a subset of 15 patients and an additional 15 matched controls, thirst perception and neuronal activity in response to beverage pictures were assessed by functional MRI.RESULTsPatients on dulaglutide reduced their fluid intake by 490 mL (95% CI: -780, -199; P = 0.002), from 2950 mL (95% CI: 2435, 3465) on placebo to 2460 mL (95% CI: 1946, 2475) on dulaglutide (model estimates), corresponding to a relative reduction of 17%. Twenty-four-hour urinary output was reduced by -943 mL (95% CI: -1473, -413; P = 0.001). Thirst perception in response to beverage pictures was higher for patients with primary polydipsia than for controls, and lower for patients on dulaglutide versus placebo, but functional activity was similar among groups and treatments.CONCLUSIONSGLP-1 receptor agonists reduce fluid intake and thirst perception in patients with primary polydipsia and could therefore be a treatment option for these patients.Trial registrationClinicaltrials.gov NCT02770885.FundingSwiss National Science Foundation (grant 32473B_162608); University Hospital and University of Basel; Young Talents in Clinical Research grant from the Swiss Academy of Medical Sciences and the Gottfried & Julia Bangerter-Rhyner Foundation; Top-up Grant from the PhD Programme in Health Sciences, University of Basel.

Drosophila melanogaster: A Powerful Tiny Animal Model for the Study of Metabolic Hepatic Diseases

Animal experimentation is limited by unethical procedures, time-consuming protocols, and high cost. Thus, the development of innovative approaches for disease treatment based on alternative models in a fast, safe, and economic manner is an important, yet challenging goal. In this paradigm, the fruit-fly Drosophila melanogaster has become a powerful model for biomedical research, considering its short life cycle and low-cost maintenance. In addition, biological processes are conserved and homologs of ∼75% of human disease-related genes are found in the fruit-fly. Therefore, this model has been used in innovative approaches to evaluate and validate the functional activities of candidate molecules identified via in vitro large-scale analyses, as putative agents to treat or reverse pathological conditions. In this context, Drosophila offers a powerful alternative to investigate the molecular aspects of liver diseases, since no effective therapies are available for those pathologies. Non-alcoholic fatty liver disease is the most common form of chronic hepatic dysfunctions, which may progress to the development of chronic hepatitis and ultimately to cirrhosis, thereby increasing the risk for hepatocellular carcinoma (HCC). This deleterious situation reinforces the use of the Drosophila model to accelerate functional research aimed at deciphering the mechanisms that sustain the disease. In this short review, we illustrate the relevance of using the fruit-fly to address aspects of liver pathologies to contribute to the biomedical area.