Exenatide as a Novel Weight Loss Modality in Patients Without Diabetes

Comparison of exenatide alone or combined with metformin versus metformin in the treatment of polycystic ovaries: a systematic review and meta-analysis

BACKGROUND

Polycystic ovary syndrome (PCOS) is the most common cause of anovulatory infertility in women of childbearing age. Randomized controlled trials (RCTs) have reported that exenatide and metformin are effective in the treatment of PCOS. In this meta-analysis, we aimed to compare the effectiveness and safety of exenatide alone or in combination with metformin versus metformin in patients suffering from PCOS.

METHODS

RCTs of exenatide therapy were identified through a search of electronic databases in November 2022 and updated in October 2023. Eligible studies were identified independently by the reviewers. Outcomes were analysed with Revman 5.4.

RESULTS

Nine RCTs among 214 studies on 1059 women with PCOS were included in the analysis, and among the nine RCTs, eight studies compared exenatide with metformin. Our meta-analysis demonstrated that exenatide was more effective than metformin in terms of pregnancy rate (RR 1.85 [95% CI 1.19,2.86] P = 0.006), sex hormone-binding globulin (SHBG) (MD 5 [95% CI 3.82,6.18] P < 0.001), and follicle-stimulating hormone (FSH) (MD 0.82 [95% 0.41,1.24] P < 0.001). The reductions in total testosterone (TT) (SMD -0.43 [95% CI -0.84, -0.03] P = 0.04) was more significant after treatment with exenatide than after treatment with metformin. In terms of safety, exenatide had a lower diarrhea rate (RR 0.11 [95% CI 0.01, 0.84]) than metformin. In the other three studies, exenatide plus metformin was compared with metformin. Exenatide combined with metformin was more effective in improving SHBG (MD 10.38[95%CI 6.7,14.06] P < 0.001), Matsuda index (MD 0.21[95%CI 0.05,0.37]) and reducing free androgen index (FAI) (MD -3.34 [-4.84, -1.83] P < 0.001), Weight (MD -2.32 [95%CI -3.89, -0.66]) and WC (MD-5.61[95%CI -8.4, -2.82] P < 0.001). The incidence of side effects between exenatide plus metformin and metformin was not statistically significant.

CONCLUSIONS

Exenatide alone or in combination with metformin is more effective than metformin for women with PCOS. Considering the evidence on effectiveness and safety, exenatide alone or in combination with metformin may be a better treatment approach than metformin for women with PCOS.

TRIAL REGISTRATION

INPLASY https://inplasy.com/inplasy-protocols/ ID: 10.37766/inplasy2022.11.0055.

The therapeutic effects of glucagon-like peptide-1 receptor agonists and metformin on polycystic ovary syndrome: A protocol for systematic review and meta-analysis

BACKGROUND

Obesity and insulin resistance (IR) are common in polycystic ovary syndrome (PCOS), which contribute to reproductive and metabolic abnormalities. Metformin increases insulin sensitivity, but it is associated with unsatisfied benefits of weight loss. Recent studies have reported that glucagon-like peptide 1 (GLP-1) receptor agonists improve IR and reduce weight in women with PCOS. We conducted a systematic review and meta-analysis to compare the effects between GLP-1 receptor agonists and metformin, and between GLP-1 receptor agonist-metformin combination and GLP-1 receptor agonists in overweight/obese women with PCOS on anthropometric, metabolic, reproductive outcomes.

METHODS

Databases including PubMed, EMBASE, Web of Science, and Cochrane Library were selected to search for randomized controlled trials (RCTs) published in English up to March 2020. Eligible studies were identified according to the inclusion criteria. The primary outcomes included menstrual frequency, body mass index (BMI), total testosterone, and the homeostatic model assessment of insulin resistance. GRADE criteria were implemented to assess the quality of evidence for primary outcomes.

RESULTS

Seven RCTs were selected for analysis, comprising 464 overweight/obese women with PCOS. In the low-quality evidence, a meta-analysis demonstrated that GLP-1 receptor agonists showed better effects relative to metformin on the reduction of body mass index (mean difference - 1.72; 95% confidence interval -2.46 to -0.99, P < .001) and homeostatic model assessment of insulin resistance (standard mean difference -0.37; 95% confidence interval - 0.60,- 0.15, P = .001). Moreover, the combination therapy exhibited similar effects on primary outcomes relative to GLP-1 receptor agonist alone. GLP-1 receptor agonists were also found to be associated with lower abdominal girth compared to metformin. A meta-analysis of gastrointestinal discomfort showed no significant difference between GLP-1 receptor agonist and metformin therapies, and between the combination therapy and GLP-1 receptor agonist alone.

CONCLUSIONS

GLP-1 receptor agonists appear to be more beneficial for weight loss and IR improvement compared to metformin for overweight/obese women with PCOS. However, the combination treatment displays comparable effects with GLP-1 receptor agonist alone. The incidence of gastrointestinal discomforts was similar in different groups. However, the quality of the body of evidence is "low." Further prospective RCTs and cost-effectiveness analyses are also warranted to guide GLP-1 receptor agonists to treat women with PCOS.

Activation of glucagon-like peptide-1 receptors and skilled reach foraging

Glucagon‐like peptide‐1 receptor (GLP‐1R) agonists, such as exendin‐4 (Ex4), liraglutide and dulaglutide, regulate glucose homeostasis and are thus used to treat diabetes type II. GLP‐1 also contributes towards a variety of additional physiological functions, including suppression of reward and improvement of learning. Acute activation of GLP‐1R in the nucleus accumbens (NAc) shell, an area essential for motivation, reduces the motivation to consume sucrose or alcohol when assessed in a simple motor task. However, the effects of repeated administration of the different GLP‐1R agonists on behaviours in a more complex motor task are unknown. The aim was therefore to investigate the effects of repeated Ex4, liraglutide or dulaglutide on the motivation and learning of a complex motor tasks such as skilled reach foraging in the Montoya staircase test. To explore the neurophysiological correlates of the different GLP‐1R agonists on motivation, ex vivo electrophysiological recordings were conducted. In rats with an acquired skilled reach performance, Ex4 or liraglutide but not dulaglutide reduced the motivation of skilled reach foraging. In trained rats, Ex4 infusion into NAc shell decreased this motivated behaviour, and both Ex4 and liraglutide supressed the evoked field potentials in NAc shell. In rats without prior Montoya experience, dulaglutide but not Ex4 or liraglutide enhanced the learning of skilled reach foraging. Taken together, these findings indicate that the tested GLP‐1R agonists have different behavioural outcomes depending on the context.

A genomic approach to therapeutic target validation identifies a glucose-lowering GLP1R variant protective for coronary heart disease

Regulatory authorities have indicated that new drugs to treat type 2 diabetes (T2D) should not be associated with an unacceptable increase in cardiovascular risk. Human genetics may be able to guide development of antidiabetic therapies by predicting cardiovascular and other health endpoints. We therefore investigated the association of variants in six genes that encode drug targets for obesity or T2D with a range of metabolic traits in up to 11,806 individuals by targeted exome sequencing and follow-up in 39,979 individuals by targeted genotyping, with additional in silico follow-up in consortia. We used these data to first compare associations of variants in genes encoding drug targets with the effects of pharmacological manipulation of those targets in clinical trials. We then tested the association of those variants with disease outcomes, including coronary heart disease, to predict cardiovascular safety of these agents. A low-frequency missense variant (Ala316Thr; rs10305492) in the gene encoding glucagon-like peptide-1 receptor (GLP1R), the target of GLP1R agonists, was associated with lower fasting glucose and T2D risk, consistent with GLP1R agonist therapies. The minor allele was also associated with protection against heart disease, thus providing evidence that GLP1R agonists are not likely to be associated with an unacceptable increase in cardiovascular risk. Our results provide an encouraging signal that these agents may be associated with benefit, a question currently being addressed in randomized controlled trials. Genetic variants associated with metabolic traits and multiple disease outcomes can be used to validate therapeutic targets at an early stage in the drug development process.

Gender-related different effects of a combined therapy of Exenatide and Metformin on overweight or obesity patients with type 2 diabetes mellitus

BACKGROUND

Although men and women have similar diabetes prevalence, the same medicine will cause different therapeutic results in different genders. To understand the molecular mechanism, we explored the effects of a combined therapy of Exenatide and Metformin on obesity and overweight female and male patients with newly diagnosed type 2 diabetes mellitus (T2DM).

METHODS

One hundred and five overweight and obesity patients with newly diagnosed T2DM (n=54 female in a female group and n=51 males in a male group) received the therapy: 5 μg Exenatide+0.5 g MET twice daily for 4 weeks, then 10 μg Exenatide+0.5 g MET twice daily for 24 weeks.

RESULTS

There was an average of 8.2 ± 2.4 kg and 4.6 ± 2.3 kg weight loss in female and male patients, respectively. The combined therapy showed better effects on female than male patients for improving insulin sensitivity and serum lipid profile, reducing insulin resistance, increasing adiponectin levels, and decreasing the levels of HbA1c, BMI, resistin, TNF-alpha and C-reactive protein (P<0.05).

CONCLUSIONS

The combined therapy of Exenatide and MET shows better therapeutic results in female patients than in male patients. Therefore, the dual therapy is more suitable for female patients.

Exenatide in obesity with accelerated gastric emptying: a randomized, pharmacodynamics study

Obesity is associated with differences in satiety, gastric emptying (GE), gastric volume, and psychological traits. Exenatide, a short-acting glucagon-like peptide 1 (GLP-1) receptor agonist, is associated with variable weight loss. We compared the effects of exenatide, 5 μg, and placebo SQ, twice daily for 30 days on GE of solids and liquids (scintigraphy), satiety (ad libitum buffet meal), satiation (nutrient drink test, maximum tolerated volume [MTV]), and weight loss in 20 participants with documented accelerated GE of solids (T1/2 < 90 min). Exenatide delayed GE of solids (T1/2 [Δ] 86 min relative to placebo, P < 0.001) and reduced calorie intake at buffet meal ([Δ] 129 kcal compared to placebo). Median weight loss was -0.95 kg (IQR -0.7 to -2.1) for exenatide and -0.55 kg (0.3 to -2.1) for placebo (P = 0.23); 80% of exenatide group had documented reduction in weight. In the exenatide treatment group, there was an inverse correlation between gastric emptying T1/2 and MTV (R = -0.548, P = 0.089). The univariate association of weight change with posttreatment MTV was borderline (Rs = 0.43, P = 0.06); in the multiple regression model, posttreatment MTV was associated with weight change (P = 0.047). The effect of the short-acting GLP-1 receptor agonist, exenatide, on GE is associated with the change in food intake, and the latter impacts weight loss in response to exenatide treatment.

Weight loss effect of glucagon-like peptide-1 mimetics on obese/overweight adults without diabetes: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) benefit weight maintenance for diabetic patients. We performed a systematic review to evaluate its weight loss effect on obese/overweight patients without diabetes in randomized controlled trials (RCTs).

METHODS

Literature updated to May 5, 2014 from Cochrane Library, MEDLINE, EMBASE and reference lists from relevant articles were identified. RCTs with GLP-1 mimetics treating obese/overweight adults without diabetes for at least 12 weeks were assessed. Studies lacking primary measurements were excluded. Three authors extracted data independently. Either fixed-effect or random-effect models were used to calculate weighted mean differences (WMDs), combined relative risks (RR) and 95% confidence interval (CI) in meta-analyses. Intertrial heterogeneity across studies was examined by I(2) and Q statistics.

RESULTS

A total of 1345 individuals retrieved from eight studies were involved and all included trials were of mild-to-moderate bias risks. Participants in GLP-1RA groups achieved a larger weight loss than those in control groups (-2.85 kg, 95%CI -3.55 to -2.14), and liraglutide may work in a dose-dependent fashion. GLP-1RAs also reduced body mass index (BMI) and waist circumferences (WC) and benefited systolic blood pressure and triglyceride regulation. But GLP-1RAs were associated with increased nausea and vomiting events.

CONCLUSIONS

GLP-1 mimetics induce a weight loss in addition to BMI and WC reduction in obese/overweight adults without diabetes. Further long-term randomized trials and basic studies are required to investigate the mechanisms.

Acarbose, lente carbohydrate, and prebiotics promote metabolic health and longevity by stimulating intestinal production of GLP-1

The α-glucosidase inhibitor acarbose, which slows carbohydrate digestion and blunts postprandial rises in plasma glucose, has long been used to treat patients with type 2 diabetes or glucose intolerance. Like metformin, acarbose tends to aid weight control, postpone onset of diabetes and decrease risk for cardiovascular events. Acarbose treatment can favourably affect blood pressure, serum lipids, platelet aggregation, progression of carotid intima-media thickness and postprandial endothelial dysfunction. In mice, lifetime acarbose feeding can increase median and maximal lifespan-an effect associated with increased plasma levels of fibroblast growth factor 21 (FGF21) and decreased levels of insulin-like growth factor-I (IGF-I). There is growing reason to suspect that an upregulation of fasting and postprandial production of glucagon-like peptide-1 (GLP-1)-stemming from increased delivery of carbohydrate to L cells in the distal intestinal tract-is largely responsible for the versatile health protection conferred by acarbose. Indeed, GLP-1 exerts protective effects on vascular endothelium, the liver, the heart, pancreatic β cells, and the brain which can rationalise many of the benefits reported with acarbose. And GLP-1 may act on the liver to modulate its production of FGF21 and IGF-I, thereby promoting longevity. The benefits of acarbose are likely mimicked by diets featuring slowly-digested 'lente' carbohydrate, and by certain nutraceuticals which can slow carbohydrate absorption. Prebiotics that promote colonic generation of short-chain fatty acids represent an alternative strategy for boosting intestinal GLP-1 production. The health benefits of all these measures presumably would be potentiated by concurrent use of dipeptidyl peptidase 4 inhibitors, which slow the proteolysis of GLP-1 in the blood.

The modulatory role of high fat feeding on gastrointestinal signals in obesity

The gastrointestinal (GI) tract is a specialized sensory system that detects and responds to constant changes in nutrient- and bacterial-derived intestinal signals, thus contributing to controls of food intake. Chronic exposure to dietary fat causes morphological, physiological and metabolic changes leading to disruptions in the regulatory feeding pathways promoting more efficient fat absorption and utilization, blunted satiation signals and excess adiposity. Accumulating evidence demonstrates that impaired gastrointestinal signals following long-term high fat consumption are, at least partially, responsible for increased caloric intake. This review focuses on the role of dietary fat in modulating oral and post-oral chemosensory signaling elements responsible for lipid detection and responses, including changes in sensitivity to satiation signals, such as GLP-1, PYY and CCK and their impact on food intake and weight gain. Furthermore, the influence of the gut microbiota on mechanisms controlling energy regulation in the face of excessive fat exposure will be explored. The profound influence of dietary fats on altering complex regulatory feeding pathways can result in dysregulation of body weight and development of obesity, while restoration or manipulation of satiation signaling may prove an effective tool in prevention and treatment of obesity.