Glucagon-like Peptide 1 Receptor Agonists, Diabetic Retinopathy and Angiogenesis: The AngioSafe Type 2 Diabetes Study

Dipeptidyl peptidase 4 inhibitors, sodium glucose cotransporter 2 inhibitors, and glucagon-like peptide 1 receptor agonists do not worsen diabetic macular edema

AIMS

There are limited studies on dipeptidyl-peptidase 4 inhibitor (DPP-4i), sodium glucose cotransporter 2 inhibitor (SGLT2-i), and glucagon-like peptide 1 (GLP-1) receptor agonist use and occurrence of diabetic macular edema (DME). The objective of this study was to determine the association between DPP-4i, SGLT2-i, and GLP-1 receptor agonist use and occurrence of DME.

METHODS

Proportional hazard models were used to evaluate the change in hazard of developing DME associated with DPP-4i, SGLT2-i, or GLP-1 receptor agonist use. Models accounted for age at DR diagnosis, DR severity (proliferative vs non-proliferative stage), time-weighted average of HbA1c level, sex, and self-reported race/ethnicity. A p-value ≤ 0.05 was considered statistically significant.

RESULTS

The hazard ratio of developing DME after diagnosis of DR was 1.2 (CI = 0.75 to 1.99; p = 0.43) for DPP-4i use, 0.93 (CI = 0.54 to 1.61; p = 0.81) for GLP-1 receptor agonist use, 0.82 (CI = 0.20 to 3.34; p = 0.78) for SGLT2-i use, 1.1 (CI = 0.75 to 1.59; p = 0.66) for any one medication use, 1.1 (CI = 0.62 to 2.09; p = 0.68) and for any two or more medications use.

CONCLUSIONS

We did not find an association between DPP-4i, SGLT2-i, or GLP-1 receptor agonist use and increased hazard of development of DME among patients with DR.

Unlocking longevity with GLP-1: A key to turn back the clock?

Traditionally known for managing blood sugar, GLP-1, a gut hormone, is emerging as a potential key to both lengthening lifespan and combating age-related ailments. While widely recognized for its role in blood sugar control, GLP-1 is increasingly recognized for its diverse effects on various biological pathways beyond glucose metabolism. Research across organisms and humans suggests that activating GLP-1 receptors significantly impacts cellular processes linked to aging. Its ability to boost mitochondrial function, enhance cellular stress resistance, and quell inflammation hints at its wider influence on aging mechanisms. This intricate interplay between GLP-1 and longevity appears to act through multiple pathways. One key effect is its ability to modulate insulin sensitivity, potentially curbing age-related metabolic issues like type 2 diabetes. Its neuroprotective properties also make it a promising candidate for addressing age-related cognitive decline and neurodegenerative diseases. Furthermore, preclinical studies using GLP-1 analogs or agonists have shown promising results in extending lifespan and improving healthspan in various model organisms. These findings provide a compelling rationale for exploring GLP-1-based interventions in humans to extend healthy aging. However, despite the exciting therapeutic prospects of GLP-1 in promoting longevity, challenges remain. Determining optimal dosages, establishing long-term safety profiles, and investigating potential adverse effects require comprehensive clinical investigations before we can confidently translate these findings to humans. This article emphasises the wide applicability of GLP-1.

The Cardiovascular Benefits of Glucagon-Like Peptide-1 Receptor Agonists as Novel Diabetes Drugs Are Mediated via the Suppression of miR-203a-3p and miR-429 Expression

Coronary artery disease (CAD) is associated with a high fatality rate and a heavy global health care burden. Glucagon-like peptide-1 (GLP-1) exerts positive cardiovascular effects, although the molecular mechanisms are unclear. Therefore, this study aimed to verify whether the cardioprotective effects of GLP-1 are mediated through the regulation of micro-RNA (miRNA) expression. Follow-up assessments were conducted for 116 patients with type 2 diabetes mellitus (T2DM) alone (controls) and 123 patients with both T2DM and CAD. After matching, each group comprised 63 patients, and age, body mass index, and serum levels of total cholesterol (TC), high-density lipoprotein cholesterol (HDL), low-density lipoprotein cholesterol (LDL), triglycerides (TG), and hemoglobin A1C (HbA1c) were compared. Subsequently, the expression profiles of four circulating miRNAs (miR-203a-3p, miR-429, miR-205-5p, and miR-203b-5p) were assessed via quantitative reverse transcription real-time polymerase chain reaction in the 63 patients with diabetes and CAD between 6 months (baseline) and 12 months after the initiation of GLP-1 receptor (GLP-1R) therapy. As expected, the metabolic factors were significantly improved after 6 months of treatment with GLP-1R compared with pre-treatment values, and the expression levels of two of the miRNAs (miR-203a-3p and miR-429) decreased from baseline levels in those with diabetes and CAD. The results suggest that the cardiovascular benefits induced by GLP-1R are mediated via suppressed expression of two miRNAs: miR-203a-3p and miR-429.

Incidence and progression of diabetic retinopathy in patients treated with glucagon-like peptide-1 receptor agonists versus sodium-glucose cotransporter 2 inhibitors: A population-based cohort study

AIM

Glucagon-like peptide 1 receptor agonists (GLP1RA) and sodium-glucose cotransporter 2 inhibitors (SGLT2i) are both recommended for patients with diabetes, yet their effects on the development or progression of diabetic retinopathy (DR) are largely unknown.

METHODS

In this retrospective cohort study, data were collected from a nationwide database. Patients with diabetes who initiated treatment with a GLP1RA or SGLT2i between 1 May 2016 and 31 December 2017, were identified. Patients were divided into those with or without a previous diagnosis of DR and then categorized into the GLP1RA and the SGLT2i groups according to drug use. The primary outcome of interest in the DR group was the composite of new-onset proliferative DR, vitreous haemorrhage and tractional retinal detachment (RD). In the non-DR group, the primary outcome was the composite of newly diagnosed DR of any severity, vitreous haemorrhage and RD.

RESULTS

In total, 97 413 patients were identified. After matching, 1517 patients were treated with a GLP1RA and 3034 with an SGLT2i in the DR cohort. In the non-DR cohort, 9549 initiated a GLP1RA and 19 098 initiated an SGLT2i. In patients with pre-existing DR, the incidence of any DR progression event was significantly higher in the GLP1RA group than the SGLT2i group (subdistribution hazard ratio 1.50, 95% confidence interval 1.01-2.23), primarily because of the increased risk of tractional RD. In patients without DR at baseline, the risks of all ocular outcomes were similar between the GLP1RA and SGLT2i groups.

CONCLUSIONS

In patients with diabetes mellitus and established DR, GLP1RA treatment was associated with increased risks of DR progression compared with SGLT2i use.

Risk of diabetic retinopathy and diabetic macular oedema with sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists in type 2 diabetes: a real-world data study from a global federated database

AIMS/HYPOTHESIS

A protective role of sodium-glucose cotransporter 2 inhibitors (SGLT2is) and glucagon-like peptide 1 receptor agonists (GLP1-ra) in the development of diabetic retinopathy and diabetic macular oedema has been described in some recent studies, which may extend beyond glycaemic control. We aimed to review the clinical impact of SGLT2i and GLP1-ra therapy on the risk of diabetic retinopathy and diabetic macular oedema in individuals with type 2 diabetes taking insulin.

METHODS

This is a retrospective cohort analysis of approximately two million people with type 2 diabetes receiving insulin across 97 healthcare organisations using a global federated health research network (TriNetX, Cambridge, USA). Two intervention cohorts (SGLT2i + insulin, n=176,409; GLP1-ra + insulin, n=207,034) were compared against a control cohort (insulin with no SGLT2i/GLP1-ra, n=1,922,312). Kaplan-Meier survival analysis was performed and estimated HRs were reported for each outcome. Propensity score was used to 1:1 match for age, sex, ischaemic heart disease, hypertension, microvascular complications, chronic kidney disease, HbA1c, BMI and use of pioglitazone, lipid modifying agents, antilipemic agents, ACE inhibitors, angiotensin II inhibitors and metformin. A sub-analysis comparing the two intervention cohorts was also performed.

RESULTS

SGLT2i with insulin was associated with a reduced HR (95% CI) for diabetic macular oedema compared with the control cohort (0.835; 0.780, 0.893), while GLP1-ra with insulin demonstrated a lack of signal with no statistical significance to the HR (1.013; 0.960, 1.069). SGLT2i with insulin was not associated with a clinically significant increase in the risk of developing diabetic retinopathy (1.076; 1.027, 1.127), while GLP1-ra with insulin increased diabetic retinopathy risk (1.308; 1.261, 1.357). Compared with SGLT2i with insulin, GLP1-ra with insulin was associated with higher risk of diabetic retinopathy (1.205; 1.153, 1.259) and diabetic macular oedema (1.130; 1.056, 1.208).

CONCLUSIONS/INTERPRETATION

Our study suggests that the combination of SGLT2i and insulin is associated with lower risk of developing diabetic macular oedema. However, the use of GLP1-ra was associated with an increased risk of diabetic retinopathy in individuals with type 2 diabetes also taking insulin. A comparative analysis showed favourable outcomes with SGLT2i and insulin in the development of diabetic macular oedema and diabetic retinopathy. RCTs using dedicated  retinal imaging are required to determine the causal relationship with these therapies.

Unlocking the Potential: Semaglutide's Impact on Alzheimer's and Parkinson's Disease in Animal Models

Semaglutide (SEM), a glucagon-like peptide-1 receptor agonist, has garnered increasing interest for its potential therapeutic effects in neurodegenerative disorders such as Alzheimer's disease (AD) and Parkinson's disease (PD). This review provides a comprehensive description of SEM's mechanism of action and its effects in preclinical studies of these debilitating conditions. In animal models of AD, SEM has proved beneficial effects on multiple pathological hallmarks of the disease. SEM administration has been associated with reductions in amyloid-beta plaque deposition and mitigation of neuroinflammation. Moreover, SEM treatment has been shown to ameliorate behavioral deficits related to anxiety and social interaction. SEM-treated animals exhibit improvements in spatial learning and memory retention tasks, as evidenced by enhanced performance in maze navigation tests and novel object recognition assays. Similarly, in animal models of PD, SEM has demonstrated promising neuroprotective effects through various mechanisms. These include modulation of neuroinflammation, enhancement of mitochondrial function, and promotion of neurogenesis. Additionally, SEM has been shown to improve motor function and ameliorate dopaminergic neuronal loss, offering the potential for disease-modifying treatment strategies. Overall, the accumulating evidence from preclinical studies suggests that SEM holds promise as a novel therapeutic approach for AD and PD. Further research is warranted to elucidate the underlying mechanisms of SEM's neuroprotective effects and to translate these findings into clinical applications for the treatment of these devastating neurodegenerative disorders.

Glucagon-like peptide-1 receptor agonists rescued diabetic vascular endothelial damage through suppression of aberrant STING signaling

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) protect against diabetic cardiovascular diseases and nephropathy. However, their activity in diabetic retinopathy (DR) remains unclear. Our retrospective cohort study involving 1626 T2DM patients revealed superior efficacy of GLP-1 RAs in controlling DR compared to other glucose-lowering medications, suggesting their advantage in DR treatment. By single-cell RNA-sequencing analysis and immunostaining, we observed a high expression of GLP-1R in retinal endothelial cells, which was down-regulated under diabetic conditions. Treatment of GLP-1 RAs significantly restored the receptor expression, resulting in an improvement in retinal degeneration, vascular tortuosity, avascular vessels, and vascular integrity in diabetic mice. GO and GSEA analyses further implicated enhanced mitochondrial gene translation and mitochondrial functions by GLP-1 RAs. Additionally, the treatment attenuated STING signaling activation in retinal endothelial cells, which is typically activated by leaked mitochondrial DNA. Expression of STING mRNA was positively correlated to the levels of angiogenic and inflammatory factors in the endothelial cells of human fibrovascular membranes. Further investigation revealed that the cAMP-responsive element binding protein played a role in the GLP-1R signaling pathway on suppression of STING signaling. This study demonstrates a novel role of GLP-1 RAs in the protection of diabetic retinal vasculature by inhibiting STING-elicited inflammatory signals.

Weight loss, bariatric surgery, and novel antidiabetic drugs effects on diabetic retinopathy: a review

PURPOSE OF REVIEW

Diabetic retinopathy (DR) is a leading cause of visual impairment, and the increasing prevalence of diabetes and obesity will impact rates of visual impairment moving forward. Our review aims to synthesize the current body of evidence regarding the impact of lifestyle interventions, such as weight loss, bariatric surgery, and novel antidiabetic drugs, on DR.

RECENT FINDINGS

Literature review revealed insufficient evidence regarding the impact of weight loss on DR. Preoperative DR patients undergoing bariatric surgery were found to have similar short-term chances of improvement or worsening DR. Progression of DR with glucagon-like peptide 1 receptor agonists treatments appears unrelated to specific drugs and was also observed with traditional antidiabetic medications.

SUMMARY

Rapidly correcting HbA1c levels (≥2%) can paradoxically lead to early worsening DR. Patients considering weight loss, bariatric surgery, and novel antidiabetic drugs should be aware of the potential for DR progression, but they should not be discouraged, as achieving glycemic control is essential for reducing long-term morbidity and mortality from other diabetes-related complications. It is advisable to conduct a baseline retinal examination before treatment and continue monitoring during therapy. Further research is needed to understand the long-term effects of these treatments on DR.

Association between Glucagon-like Peptide-1 Receptor Agonists and the Risk of Glaucoma in Individuals with Type 2 Diabetes

PURPOSE

To examine the association between glucagon-like peptide-1 receptor agonist (GLP-1RA) use and the development of glaucoma in individuals with type 2 diabetes.

DESIGN

Nationwide, nested case-control study.

PARTICIPANTS

From a nationwide cohort of 264 708 individuals, we identified 1737 incident glaucoma cases and matched them to 8685 glaucoma-free controls, all aged more than 21 years and treated with metformin and a second-line antihyperglycemic drug formulation, with no history of glaucoma, eye trauma, or eye surgery.

METHODS

Cases were incidence-density-matched to 5 controls by birth year, sex, and date of second-line treatment initiation.

MAIN OUTCOME MEASURES

Conditional logistic regression was used to calculate adjusted hazard ratios (HRs) with 95% confidence intervals (CIs) for glaucoma, defined by first-time diagnosis, first-time use of glaucoma-specific medication, or first-time glaucoma-specific surgical intervention.

RESULTS

Compared with the reference group, who received treatments other than GLP-1RA, individuals who were exposed to GLP-1RA treatment exhibited a lower risk of incident glaucoma (HR, 0.81; CI, 0.70-0.94; P = 0.006). Prolonged treatment extending beyond 3 years lowered the risk even further (HR, 0.71; CI, 0.55-0.91; P = 0.007). Treatment with GLP-1RA for 0 to 1 year (HR, 0.89; CI, 0.70-1.14; P = 0.35) and 1 to 3 years (HR, 0.85; CI, 0.67-1.06; P = 0.15) was not significant.

CONCLUSIONS

Exposure to GLP-1RA was associated with a lower risk of developing glaucoma compared with receiving other second-line antihyperglycemic medication.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Effects of newer-generation anti-diabetics on diabetic retinopathy: a critical review

Diabetic retinopathy (DR) is the leading etiology of blindness in the working population of the USA. Its long-term management relies on effective glycemic control. Seven anti-diabetic classes have been introduced for patients with type 2 diabetes (T2D) in the past two decades, with different glucose-lowering and cardiovascular benefits. Yet, their effects specifically on DR have not been studied in detail. A systematic review of the literature was conducted to investigate this topic, focusing on the available clinical data for T2D. Published studies were evaluated based on their level of statistical evidence, as long as they incorporated at least one endpoint or adverse event pertaining to retinal health. Fifty nine articles met our inclusion criteria and were grouped per anti-diabetic class as follows: alpha-glucosidase inhibitors (1), peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists (8), amylin analogs (1), glucagon-like peptide-1 (GLP-1) receptor agonists (28), dipeptidyl peptidase 4 (DPP-4) inhibitors (9), and sodium glucose co-transporter-2 (SGLT-2) inhibitors (9), plus one retrospective study and two meta-analyses evaluating more than one of the aforementioned anti-diabetic categories. We also reviewed publicly-announced results of trials for the recently-introduced class of twincretins. The available data indicates that most drugs in the newer anti-diabetic classes are neutral to DR progression; however, there are subclasses differences in specific drugs and T2D populations. In particular, there is evidence suggesting there may be worse diabetic macular edema with PPAR-gamma agonists, potential slight DR worsening with semaglutide (GLP-1 receptor agonist), and potential slight increase in the incidence of retinal vein occlusion in elderly and patients with advanced kidney disease receiving SGLT-2 inhibitors. All these warrant further investigation. Longer follow-up and systematic assessment of at least one DR-related endpoint are highly recommended for all future trials in the T2D field, to ultimately address this topic.

Blood Monocyte Phenotype Is A Marker of Cardiovascular Risk in Type 2 Diabetes

BACKGROUND

Diabetes is a major risk factor for atherosclerotic cardiovascular diseases with a 2-fold higher risk of cardiovascular events in people with diabetes compared with those without. Circulating monocytes are inflammatory effector cells involved in both type 2 diabetes (T2D) and atherogenesis.

METHODS

We investigated the relationship between circulating monocytes and cardiovascular risk progression in people with T2D, using phenotypic, transcriptomic, and metabolomic analyses. cardiovascular risk progression was estimated with coronary artery calcium score in a cohort of 672 people with T2D.

RESULTS

Coronary artery calcium score was positively correlated with blood monocyte count and frequency of the classical monocyte subtype. Unsupervised k-means clustering based on monocyte subtype profiles revealed 3 main endotypes of people with T2D at varying risk of cardiovascular events. These observations were confirmed in a validation cohort of 279 T2D participants. The predictive association between monocyte count and major adverse cardiovascular events was validated through an independent prospective cohort of 757 patients with T2D. Integration of monocyte transcriptome analyses and plasma metabolomes showed a disruption of mitochondrial pathways (tricarboxylic acid cycle, oxidative phosphorylation pathway) that underlined a proatherogenic phenotype.

CONCLUSIONS

In this study, we provide evidence that frequency and monocyte phenotypic profile are closely linked to cardiovascular risk in patients with T2D. The assessment of monocyte frequency and count is a valuable predictive marker for risk of cardiovascular events in patients with T2D.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT04353869.

Endothelial progenitor cells as biomarkers of diabetes-related cardiovascular complications

Diabetes mellitus (DM) constitutes a chronic metabolic disease characterized by elevated levels of blood glucose which can also lead to the so-called diabetic vascular complications (DVCs), responsible for most of the morbidity, hospitalizations and death registered in these patients. Currently, different approaches to prevent or reduce DM and its DVCs have focused on reducing blood sugar levels, cholesterol management or even changes in lifestyle habits. However, even the strictest glycaemic control strategies are not always sufficient to prevent the development of DVCs, which reflects the need to identify reliable biomarkers capable of predicting further vascular complications in diabetic patients. Endothelial progenitor cells (EPCs), widely known for their potential applications in cell therapy due to their regenerative properties, may be used as differential markers in DVCs, considering that the number and functionality of these cells are affected under the pathological environments related to DM. Besides, drugs commonly used with DM patients may influence the level or behaviour of EPCs as a pleiotropic effect that could finally be decisive in the prognosis of the disease. In the current review, we have analysed the relationship between diabetes and DVCs, focusing on the potential use of EPCs as biomarkers of diabetes progression towards the development of major vascular complications. Moreover, the effects of different drugs on the number and function of EPCs have been also addressed.

Evaluating Glycemic Control Efficacy and Safety of the Oral Small Molecule Glucagon-Like Peptide 1 Receptor Agonist Danuglipron in Type 2 Diabetes Patients: A Systemic Review and Meta-Analysis

Introduction

Diabetes Mellitus (DM) is a significant global health concern, with Type 2 DM (T2DM) being highly prevalent. Glucagon-Like Peptide 1 receptor agonists (GLP-1RA), such as Danuglipron, offer potential benefits in T2DM management. This meta-analysis examines the safety and efficacy of Danuglipron, focusing on adverse outcomes and glycemic parameters.

Methods

A systematic search was conducted in PubMed, Scopus, and Cochrane Library for RCTs involving Danuglipron till August 2023, following PRISMA guidelines. The Cochrane risk-of-bias tool was used for quality assessment. Adverse outcomes (diarrhea, nausea, vomiting, headache, decreased appetite, dyspepsia, dizziness) and glycemic parameters like changes in HbA1C, fasting plasma glucose (FPG), and body weight were analyzed.

Results

Four RCTs published from 2021 to 2023 were included. Both doses of Danuglipron were associated with diarrhea (RR=2.66, 90% CI: 1.32 to 5.35, p=0.02), nausea (RR=5.5, 90% CI: 3.4 to 8.88, p<0.00001), and vomiting (RR=5.98, 90% CI: 2.93 to 12.23, p=0.0001). The 120mg dose showed decreased appetite (RR=3.46, 90% CI: 1.57 to 7.62, p=0.01), dyspepsia (RR=4.04, 90% CI: 1.93 to 8.43, p=0.002), and dizziness (RR=5.08, 90% CI: 1.45 to 17.82, p=0.03). Reductions in HbA1C (SMD -1.09, 90% CI -1.39 to -0.8, p < 0.00001), FPG (SMD -1.10, 90% CI -1.46 to -0.75, p < 0.00001), and body weight (SMD -1.08, 90% CI -1.42 to -0.74, p < 0.00001) were observed for both doses.

Conclusion

Danuglipron demonstrates potential for glycemic control and weight reduction in T2DM. Adverse outcomes include diarrhea, nausea, vomiting, and decreased appetite, with dose-related effects. Clinicians must weigh benefits against side effects when considering Danuglipron for T2DM management.

The Utilization of Glucagon-like Peptide 1 Agonists and Risk of Following External Eye Diseases in Type 2 Diabetes Mellitus Individuals: A Population-Based Study

The glucagon-like peptide 1 (GLP-1) agonist showed anti-hyperglycemic and anti-inflammatory effects, which may retard the risk of external eye disease. The protective effect of GLP-1 agonist and dry eye disease (DED) was found, while the relationship between GLP-1 agonist and other corneal diseases was not clear. Herein, we aim to evaluate the association between the usage of GLP-1 agonists and the development of the following external eye disease in type 2 diabetes mellitus (T2DM) patients. A retrospective cohort study using the National Health Insurance Research Database (NHIRD) of Taiwan was conducted. The T2DM patients were divided into those with GLP-1 treatment and those without GLP-1 treatment and matched with a 1:2 ratio. The main outcomes were the development of dry eye disease (DED), superficial keratitis, and infectious keratitis. The Cox proportional hazard regression was adopted to produce the adjusted hazard ratio (aHR) with a 95% confidence interval (CI) of external eye diseases between groups. There were 115, 54, and 11 episodes of DED, superficial keratitis, and infectious keratitis in the GLP-1 group. Another 280, 168, and 31 events of DED, superficial keratitis, and infectious keratitis were recorded in the control group. The GLP-1 group demonstrated a significantly lower incidence of DED (aHR: 0.853, 95% CI: 0.668-0.989, p = 0.0356) and superficial keratitis (aHR: 0.670, 95% CI: 0.475-0.945, p = 0.0107) compared to the control group. In the subgroup analyses, the correlation of GLP-1 agonist and DED development was more prominent in patients younger than 60 years old (p = 0.0018). In conclusion, the GLP-1 agonist treatments are significantly associated with a lower incidence of subsequent DED and superficial keratitis, while the relationship was not significant between GLP-1 agonist usage and infectious keratitis.

An Update on Strategies to Deliver Protein and Peptide Drugs to the Eye

In the past few decades, advancements in protein engineering, biotechnology, and structural biochemistry have resulted in the discovery of various techniques that enhanced the production yield of proteins, targetability, circulating half-life, product purity, and functionality of proteins and peptides. As a result, the utilization of proteins and peptides has increased in the treatment of many conditions, including ocular diseases. Ocular delivery of large molecules poses several challenges due to their high molecular weight, hydrophilicity, unstable nature, and poor permeation through cellular and enzymatic barriers. The use of novel strategies for delivering protein and peptides such as glycoengineering, PEGylation, Fc-fusion, chitosan nanoparticles, and liposomes have improved the efficacy, safety, and stability, which consequently expanded the therapeutic potential of proteins. This review article highlights various proteins and peptides that are useful in ocular disorders, challenges in their delivery to the eye, and strategies to enhance ocular bioavailability using novel delivery approaches. In addition, a few futuristic approaches that will assist in the ocular delivery of proteins and peptides were also discussed.

Untargeted Multiomics Approach Coupling Lipidomics and Metabolomics Profiling Reveals New Insights in Diabetic Retinopathy

Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus (DM) which is the main cause of vision loss in the working-age population. Currently known risk factors such as age, disease duration, and hemoglobin A1c lack sufficient efficiency to distinguish patients with early stages of DR. A total of 194 plasma samples were collected from patients with type 2 DM and DR (moderate to proliferative (PDR) or control (no or mild DR) matched for age, gender, diabetes duration, HbA1c, and hypertension. Untargeted lipidomic and metabolomic approaches were performed. Partial-least square methods were used to analyze the datasets. Levels of 69 metabolites and 85 lipid species were found to be significantly different in the plasma of DR patients versus controls. Metabolite set enrichment analysis indicated that pathways such as metabolism of branched-chain amino acids (methylglutaryl carnitine p = 0.004), the kynurenine pathway (tryptophan p < 0.001), and microbiota metabolism (p-Cresol sulfate p = 0.004) were among the most enriched deregulated pathways in the DR group. Moreover, Glucose-6-phosphate (p = 0.001) and N-methyl-glutamate (p < 0.001) were upregulated in DR. Subgroup analyses identified a specific signature associated with PDR, macular oedema, and DR associated with chronic kidney disease. Phosphatidylcholines (PCs) were dysregulated, with an increase of alkyl-PCs (PC O-42:5 p < 0.001) in DR, while non-ether PCs (PC 14:0-16:1, p < 0.001; PC 18:2-14:0, p < 0.001) were decreased in the DR group. Through an unbiased multiomics approach, we identified metabolites and lipid species that interestingly discriminate patients with or without DR. These features could be a research basis to identify new potential plasma biomarkers to promote 3P medicine.

Semaglutide-eye-catching results

Semaglutide is a glucagon-like peptide-1 receptor agonist used either orally every day or subcutaneously once a week for the treatment of type 2 diabetes mellitus and, more recently, at higher doses, for the treatment of obesity. Both diseases are reaching epidemic proportions and often coexist, posing patients with a high risk for cardiovascular disease and death. Therefore, an agent such as semaglutide, which offers clinically significant weight loss and cardiovascular benefits, is essential and will be increasingly used in high-risk patients. However, during the SUSTAIN clinical trial program (Semaglutide Unabated Sustainability in treat-ment of type 2 diabetes), a safety issue concerning the progression and worsening of diabetic retinopathy emerged. The existing explanation so far mainly supports the role of the magnitude and speed of HbA1c reduction, a phenomenon also associated with insulin treatment and bariatric surgery. Whether and to which extent the effect is direct is still a matter of debate and an intriguing topic to investigate for suitable preventative and rehabilitative purposes. In this minireview, we will summarize the available data and suggest guidelines for a comprehensive semaglutide clinical utilization until new evidence becomes available.

Evaluating the Effect of Hypoglycemic Agents on Diabetic Retinopathy Progression

BACKGROUND AND OBJECTIVE

Newer hypoglycemics such as dipeptidyl peptidase 4 (DPP-4) inhibitors, sodium-glucose cotransporter-2 (SGLT-2) inhibitors, glucagon-like peptide-1 (GLP-1) receptor agonists have been increasingly used in diabetes. This study aimed to assess the relationship between usage of these hypoglycemic agents and effect on diabetic retinopathy (DR).

MATERIALS AND METHODS

Using the Vestrum Health Retina Database, patients with DR with 1 year follow-up after use of a hypoglycemic agent were included and stratified by agent, including no pharmacotherapy.

RESULTS

Of 60,649 eyes, in 1 year after hypoglycemic agent usage, progression rates from severe nonproliferative diabetic retinopathy (NPDR) to proliferative diabetic retinopathy (PDR) were the following: DPP-4 (17%), SGLT-2 (12%), GLP-1 (21%), metformin (18%), and none (20%). Progression rates from moderate NPDR to severe NPDR or PDR were the following: DPP-4 (11%), SGLT-2 (10%), GLP-1 (11%), metformin (10%), none (13%). Progression rates from mild NPDR to moderate/severe NPDR or PDR were the following: DPP-4 (6%), SGLT-2 (9%), GLP-1 (9%), metformin (7%), and none (10%).

CONCLUSIONS

Within a large real-world database, patients prescribed GLP-1 agonists were found to have DR progression rates comparable to those of patients receiving no hypoglycemic agents. [Ophthalmic Surg Lasers Imaging Retina 2023; 54(3):158-165.].

Glucagon-like peptide-1 receptor agonists and diabetic retinopathy: nationwide cohort and Mendelian randomization studies

BACKGROUND

The ability of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to decrease certain microvascular events has called for the investigation of GLP-1 RAs against diabetic retinopathy (DR), but the evidence is limited. By combining data from observational and Mendelian randomization (MR) studies, we aimed to investigate whether GLP-1 RAs decrease the risk of DR.

METHODS

We combined data from several Swedish Registers and identified patients with incident type 2 diabetes being treated with GLP-1 RAs between 2006 and 2015, and matched them to diabetic patients who did not use GLP-1 RAs as the comparisons. The Cox proportional hazards models were applied to assess the risk of DR. We further performed the summary-data-based MR (SMR) analyses based on the Genotype-Tissue Expression databases and the Genome-Wide Association Study of DR from the FinnGen consortium.

RESULTS

A total of 2390 diabetic patients were treated with GLP-1 RAs and the incidence of DR was 5.97 per 1000 person-years. Compared with diabetic patients who did not use GLP-1 RAs having an incidence of 12.85 per 1000 person-years, the adjusted hazard ratio (HR) of DR was 0.42 [95% confidence interval (CI), 0.29-0.61]. Genetically-predicted GLP1R expression (the target of GLP-1 RAs) showed an inverse association with background [odds ratio (OR)=0.83, 95% CI, 0.71-0.97] and severe nonproliferative DR (OR=0.72, 95% CI, 0.53-0.98), and a non-significant association with overall (OR=0.97, 95% CI, 0.92-1.03) and proliferative DR (OR=0.98, 95% CI, 0.91-1.05).

CONCLUSIONS

Both observational and mendelian randomization analyses showed a significantly lower risk of DR for patients treated with GLP-1 RAs, which calls for further studies to validate these findings.

THE ASSESSMENT OF COMPENSATION OF CARBOHYDRATE METABOLISM IN PATIENTS WITH TYPE 2 DIABETES MELLITUS WITH METABOLIC SYNDROME BEYOND THE LIMITS OF GLYCATED HEMOGLOBIN

OBJECTIVE

The aim: To investigate glycemic variability in type 2 diabetes patients with metabolic syndrome (MS) and to assess its effect on diabetes compensation.

PATIENTS AND METHODS

Materials and methods: We used traditional indicators of glycemia variability according to the recommendations of the American Diabetes Association Professional Practice Committee. We proved that patients with type 2 diabetes mellitus with MS reliably have worse CGM indicators: Time in range TIR: (3.9-10.0 mmol/l) - 53.30±5.90%; Time above range (TAR): (time above range) (>10.1 mmol/l) - 43.33±5.96%; Time above TAR range (>13.9 mmol/l) - 22.1±3.91%; Glucose Variability СV - 44.10±4.89% compared to patients with type 2 diabetes without MS, which proves the negative effect of insulin resistance on compensation of diabetes.

RESULTS

Results: Determination of the level of EI in the blood, calculation of the Caro index, HOMA-IR are informative for verifying the presence of IR in patients with type 2 diabetes with MS. For optimal diabetes control, in addition to HbA1c, we must consider CGM data and % Time in range (TIR).

CONCLUSION

Conclusions: TIR should be used as a target point and an indicator of glycemic control in routine clinical practice. TIR provides accurate data on a patient's glycemic status and helps better control diabetes.

Glucagon-like peptide 1-receptor agonists and A1c: Good for the heart but less so for the eyes?

BACKGROUND AND AIMS

Glucagon-like peptide1-receptor agonists (GLP1-RA) decrease major adverse cardiovascular events (MACE) in people with type 2 diabetes mellitus and cardiovascular disease (CVD). Caution is recommended for semaglutide and dulaglutide with risk of exacerbating diabetic retinopathy (DR). Analyses were performed to determine if worsening of DR was dependent on drug class or fall in A1c.

RESEARCH DESIGN AND METHODS

Meta-analyses and meta-regressions (MR) were performed on the 7 major cardiovascular outcome trial (CVOTs) (n = 56004 patients) of GLP1-RA. A second analysis of 11 studies (n = 11894 subjects) with semaglutide documenting DR followed.

RESULTS

Six of the CVOTs evaluated DR. For the GLP1-RA class, there was no increase in the relative rate (rr) for retinopathy (rr = 1.09,95%CI; 0.925,1.289, p = 0.30), with only an increase with parenteral semaglutide (rr = 1.73; 1.10:2.71, p = 0.02). MR showed that decreases in A1c correlated with decreases in MACE (log rr = 0.364∗(Δ A1c), p = 0.014), but increases in DR (log rr= (-0.67∗(ΔA1c), p = 0.076). The change in DR was predominantly found for subcutaneous semaglutide given for >1 year (rr = 1.559,1.068,2.276, p = 0.022) and with decreases in A1c > 1.0% (rr = 1.59; 1.092,2.316, p = 0.016). For the class of GLP1-RA, the rate difference (rd) for worsening retinopathy was = 0.001 (and number needed to harm [NNH] = 1000) compared with rd for MACE = -0.013 (number needed to treat [NNT] = 77). The computation for semaglutide was NNH = 77 and NNT = 43.

CONCLUSIONS

This meta-analysis may assist in decisions balancing the relative risk (of existing retinopathy) versus benefits (to existing CVD). There should be close collaboration with ophthalmology to grade the baseline degree of retinopathy when initiating and following patients.

Will GLP-1 Analogues and SGLT-2 Inhibitors Become New Game Changers for Diabetic Retinopathy?

Diabetic retinopathy (DR) is the most frequent microvascular complication of diabetes mellitus (DM), estimated to affect approximately one-third of the diabetic population, and the most common cause of preventable vision loss. The available treatment options focus on the late stages of this complication, while in the early stages there is no dedicated treatment besides optimizing blood pressure, lipid and glycemic control; DR is still lacking effective preventive methods. glucagon-like peptide 1 receptor agonists (GLP-1 Ras) and sodium-glucose cotransporter 2 (SGLT-2) inhibitors have a proven effect in reducing risk factors of DR and numerous experimental and animal studies have strongly established its retinoprotective potential. Both drug groups have the evident potential to become a new therapeutic option for the prevention and treatment of diabetic retinopathy and there is an urgent need for further comprehensive clinical trials to verify whether these findings are translatable to humans.

Evolution of Quantitative Optical Coherence Tomography Angiography Markers with Glycemic Control: A Pilot Study

Aim: We aimed to analyze changes in retinal microvascularization with intensive reduction of glycated hemoglobin A1c (HbA1c) in patients with poorly controlled diabetes using quantitative optical coherence tomography angiography (OCT-A) metrics. Method: This was a retrospective observational study in patients with uncontrolled diabetes admitted to the hospital for glycemic control. A second set of 15 healthy volunteers was included to serve as a control group. OCT-A was performed at inclusion and at 3 months to measure foveal avascular zone area (FAZA), vessel density (VD) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP), acircularity index (AI), and fractal dimension (FD). Results: This analysis included 35 patients (35 eyes): 28 type-2 diabetics and 7 type-1 diabetics. Mean HbA1c was 13.1 ± 2.0% at inclusion and 7.0 ± 1.5% at 3 months. In the short period from inclusion to 3 months post-inclusion, patients showed significant decrease in VD−DCP (28.8% vs. 27.8%; p = 0.014), a significant increase in FAZA (0.300 mm2 vs. 0.310 mm2; p < 0.001), and a significant increase in AI (1.31 vs. 1.34; p < 0.01). Multivariate analysis found an increase in FAZA was correlated with baseline HbA1c level and age (R2 = 0.330), and a decrease in VD-DCP was correlated with HbA1c decrease and diabetes duration (R2 = 0.286). Conclusions: Rapid glycemic control in patients with uncontrolled diabetes led to possible short-term microvascular damage that correlated to both initial and decreased HbA1c.

Glucagon-like peptide-1 receptor agonist, liraglutide, attenuated retinal thickening in spontaneously diabetic Torii fatty rats

BACKGROUND

This study aims to investigate the effect of the glucagon-like peptide-1 (GLP-1) receptor agonist (GLP-1RA) liraglutide on retinal pathological findings as compared with insulin and hydralazine using an animal model of type 2 diabetes with obesity, hypertension, and hyperlipidemia.

METHODS

Male spontaneously diabetic Torii (SDT) fatty rats at 8 weeks of age were randomly assigned to three groups: the liraglutide group (SDT-lira, n = 6) received a subcutaneous injection of liraglutide from the age of 8 to 16 weeks, the SDT-ins-hyd group (n = 6) was provided both insulin against hyperglycemia and hydralazine against hypertension to match levels of both blood glucose and blood pressure to those of the liraglutide group, and the control group of SDT fatty rats (SDT-vehicle, n = 7) and a nondiabetic control group of Sprague-Dawley rats (SD, n = 7) were injected with vehicle only. Both eyeballs of all groups were collected at the age of 16 weeks.

RESULTS

Retinal thickness, which was found in the SDT-vehicle group, was significantly prevented to similar levels in both the SDT-lira and SDT-ins-hyd groups. Immunohistological analysis revealed that GLP-1 receptor was not expressed in the retina of all rats. The ocular protein expression of monocyte chemoattractant protein-1, which causes a proinflammatory situation, was significantly upregulated in all SDT fatty rats as compared to SD rats, but the expression levels were similar between all SDT fatty rats. With regard to neovascularization in the eyes, there were no significant differences in protein expressions of vascular endothelial growth factor, CD31, or endothelial nitric oxide synthase in all rats.

CONCLUSIONS

The present study indicates that liraglutide prevents retinal thickening, dependent on blood glucose and blood pressure levels in SDT fatty rats without ocular neovascularization. However, the effects did not improve the ocular proinflammatory state.

Glucagon-Like Peptide-1 Receptor Agonist Use in People Living with Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Narrative Review of the Key Evidence with Practical Considerations

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are incretin-mimetic agents that are effective adjuncts in the treatment of diabetes. This class of medications is also associated with promoting weight loss and a low risk of hypoglycemia, and some have been shown to be associated with a significant reduction of major cardiovascular events. Mounting evidence suggests that GLP-1 RAs have benefits beyond reducing blood glucose that include improving kidney function in people living with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD), a common microvascular complication of T2DM. Several large clinical studies, the majority of which are cardiovascular outcome trials, indicate that GLP-1 RA therapy is safe and tolerable for people living with T2DM and compromised renal function, and also suggest that GLP-1 RAs may have renoprotective properties. Although evidence from clinical trials has shown GLP-1 RAs to be safe and efficacious in people living with T2DM and renal impairment, their use is uncommon in this patient population. With continuing developments in the field of GLP-1 RA therapy, it is important for physicians to understand the benefits and practical use of GLP-1 RAs, as well as the clinical evidence, in order to achieve positive patient outcomes. Here, we review evidence on GLP-1 RA use in people living with T2DM and CKD and summarize renal outcomes from clinical studies. We provide practical considerations for GLP-1 RA use to provide an added benefit to guide treatment in this high-risk patient population.

Glucagon-Like Peptide 1 Receptor Agonists – Potential Game Changers in the Treatment of Glaucoma?

Glaucoma is a common ocular neurodegenerative disease characterized by the progressive loss of retinal ganglion cells and their axons. It is the most common cause of irreversible blindness. With an increasing number of glaucoma patients and disease progression despite treatment, it is paramount to develop new and effective therapeutics. Emerging new candidates are the receptor agonists of the incretin hormone glucagon-like-peptide-1 (GLP-1), originally used for the treatment of diabetes. GLP-1 receptor (GLP-1R) agonists have shown neuroprotective effects in preclinical and clinical studies on neurodegenerative diseases in both the brain (e.g., Alzheimer’s disease, Parkinson’s disease, stroke and diabetic neuropathy) and the eye (e.g., diabetic retinopathy and AMD). However, there are currently very few studies investigating the protective effects of GLP-1R agonists in the treatment of specifically glaucoma. Based on a literature search on PubMed, the Cochrane Library, and ClinicalTrials.gov, this review aims to summarize current clinical literature on GLP-1 receptor agonists in the treatment of neurodegenerative diseases to elucidate their potential in future anti-glaucomatous treatment strategies.

Weight Reduction as an Adjunctive Management Strategy for Diabetic Retinopathy

As rates of global obesity and diabetes increase, diabetic retinopathy continues to grow as a frequent cause of visual impairment. Despite tremendous recent strides in therapy, a significant fraction of patients remain poorly responsive to modern interventions. Adjunctive therapy in such settings could be widely beneficial. A growing body of evidence suggests that weight reduction strategies for obesity-related diabetes have the potential to serve as important supplements to modern ophthalmic care for preservation of vision.

Liraglutide Treatment Does Not Induce Changes in the Peripapillary Retinal Nerve Fiber Layer Thickness in Patients with Diabetic Retinopathy

Purpose: Liraglutide treatment has shown promising anti-inflammatory and nerve regenerative results in preclinical and clinical trials. We sought to assess if liraglutide treatment would induce nerve regeneration through its anti-inflammatory and neurotrophic mechanisms by increasing peripapillary retinal nerve fiber layer (RNFL) thickness in individuals with long-term type 1 diabetes. Methods: Secondary analyses were performed on a prospective, double-blinded, randomized, placebo-controlled trial on adults with type 1 diabetes, distal symmetric polyneuropathy (DSPN), and confirmed diabetic retinopathy, who were randomized 1:1 to either 26 weeks placebo or liraglutide treatment. The primary endpoint was a change in peripapillary RNFL thickness between treatments, assessed by optical coherence tomography. Results: Thirty-seven participants were included in the secondary analysis. No differences in mean peripapillary RNFL thickness (overall ΔMean RNFL thickness; liraglutide -1 (±8) μm (-1%) vs. placebo -1 (±5) μm (-1%), P = 0.78, n = 37) or any of the quadrants. Peripapillary RNFL thicknesses were shown between treatments in either nonproliferative (ΔMean RNFL thickness; liraglutide -1 (±5) μm (-1%) vs. placebo 0 (±4) μm (0%), P = 0.80, N = 26) or proliferative diabetic retinopathy subgroup (ΔMean RNFL thickness; liraglutide -2 (±14) μm (-3%) vs. placebo -1 (±6) μm (-2%), P = 0.88, N = 11). Conclusions: In this study, 26 weeks of liraglutide treatment did not induce measurable changes in the assessed optic nerve thickness. Thus, this methodology does not support the induction of substantial nerve regeneration in this cohort with established retinopathy and DSPN. The trial was approved by the Danish Health and Medicines Authority. Informed consent was obtained from all participants. TODINELI study: EUDRA CT: 2013-004375-12, Ethics Ref: N-20130077 Clinical trial registration number: clinicaltrials.gov NCT02138045.

Semaglutide and Diabetic Retinopathy Risk in Patients with Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Semaglutide is a recently approved glucagon-like peptide-1 receptor agonist used to treat patients with type 2 diabetes mellitus (T2DM). The SUSTAIN 6 trial found a significantly higher rate of retinopathy complications in the semaglutide-treated group compared with the placebo group.

OBJECTIVE

This study aimed to evaluate the association between semaglutide and the risk of retinopathy in patients with T2DM.

METHODS

Electronic databases were systematically searched up to April 2021 to identify randomized controlled trials that reported diabetic retinopathy (DR) events in semaglutide-treated and control groups. A meta-analysis was conducted using Review Manager 5.4 software to calculate the risk ratio (RR) and 95% confidence intervals (CIs).

RESULTS

A total of 23 randomized trials involving 22,096 patients with T2DM were included. There were 730 incident DR cases-463 in the semaglutide group and 267 in the control group. Overall, semaglutide was not associated with increased DR risk compared with controls when all trials were combined (RR 1.14, 95% CI 0.98-1.33). Subgroup analysis showed that semaglutide was associated with an increased risk of DR compared with placebo (RR 1.24, 95% CI 1.03-1.50). Moreover, patient age ≥ 60 years and diabetes duration ≥ 10 years were also factors for increased risk of DR when using semaglutide (RR 1.27, 95% CI 1.02-1.59; RR 1.28, 95% CI 1.04-1.58, respectively).

CONCLUSIONS

Semaglutide was not associated with an increased risk of DR; however, caution regarding DR risk is needed for older patients or those with long diabetes duration when taking semaglutide.

Animal models of diabetic microvascular complications: Relevance to clinical features

Diabetes has become more common in recent years worldwide, and this growth is projected to continue in the future. The primary concern with diabetes is developing various complications, which significantly contribute to the disease's mortality and morbidity. Over time, the condition progresses from the pre-diabetic to the diabetic stage and then to the development of complications. Years and enormous resources are required to evaluate pharmacological interventions to prevent or delay the progression of disease or complications in humans. Appropriate screening models are required to gain a better understanding of both pathogenesis and potential therapeutic agents. Different species of animals are used to evaluate the pharmacological potentials and study the pathogenesis of the disease. Animal models are essential for research because they represent most of the structural, functional, and biochemical characteristics of human diseases. An ideal screening model should mimic the pathogenesis of the disease with identifiable characteristics. A thorough understanding of animal models is required for the experimental design to select an appropriate model. Each animal model has certain advantages and limitations. The present manuscript describes the animal models and their diagnostic characteristics to evaluate microvascular diabetic complications.

Deletion of GPR21 improves glucose homeostasis and inhibits the CCL2-CCR2 axis by divergent mechanisms

INTRODUCTION

A potential role for the orphan G protein-coupled receptor, GPR21, in linking immune cell infiltration into tissues and obesity-induced insulin resistance has been proposed, although limited studies in mice are complicated by non-selective deletion of Gpr21.

RESEARCH DESIGN AND METHODS

We hypothesized that a Gpr21-selective knockout mouse model, coupled with type 2 diabetes patient samples, would clarify these issues and enable clear assessment of GPR21 as a potential therapeutic target.

RESULTS

High-fat feeding studies in Gpr21^-/- mice revealed improved glucose tolerance and modest changes in inflammatory gene expression. Gpr21^-/- monocytes and intraperitoneal macrophages had selectively impaired chemotactic responses to monocyte chemoattractant protein (MCP)-1, despite unaltered expression of Ccr2. Further genotypic analysis revealed that chemotactic impairment was due to dysregulated monocyte polarization. Patient samples revealed elevated GPR21 expression in peripheral blood mononuclear cells in type 2 diabetes, which was correlated with both %HbA1c and fasting plasma glucose levels.

CONCLUSIONS

Collectively, human and mouse data suggest that GPR21 influences both glucose homeostasis and MCP-1/CCL2-CCR2-driven monocyte migration. However, a Gpr21^-/- bone marrow transplantation and high-fat feeding study in mice revealed no effect on glucose homeostasis, suggesting that there is no (or limited) overlap in the mechanism involved for monocyte-driven inflammation and glucose homeostasis.

Circulating microRNAs Signature for Predicting Response to GLP1-RA Therapy in Type 2 Diabetic Patients: A Pilot Study

Type 2 diabetes (T2D) represents one of the major health issues of this century. Despite the availability of an increasing number of anti-hyperglycemic drugs, a significant proportion of patients are inadequately controlled, thus highlighting the need for novel biomarkers to guide treatment selection. MicroRNAs (miRNAs) are small non-coding RNAs, proposed as useful diagnostic/prognostic markers. The aim of our study was to identify a miRNA signature occurring in responders to glucagon-like peptide 1 receptor agonists (GLP1-RA) therapy. We investigated the expression profile of eight T2D-associated circulating miRNAs in 26 prospectively evaluated diabetic patients in whom GLP1-RA was added to metformin. As expected, GLP1-RA treatment induced significant reductions of HbA1c and body weight, both after 6 and 12 months of therapy. Of note, baseline expression levels of the selected miRNAs revealed two distinct patient clusters: “high expressing” and “low expressing”. Interestingly, a significantly higher percentage of patients in the high expression group reached the glycemic target after 12 months of treatment. Our findings suggest that the evaluation of miRNA expression could be used to predict the likelihood of an early treatment response to GLP1-RA and to select patients in whom to start such treatment, paving the way to a personalized medicine approach.

Effect of glucagon-like peptide-1 receptor agonists in subjects with type 2 diabetes mellitus: A meta-analysis

WHAT IS KNOWN AND OBJECTIVE

We performed a meta-analysis to evaluate the effects of glucagon-like peptide-1 receptor agonists compared to placebo on cardiovascular, kidney-related, and eye-related disease outcomes or on mortality in subjects with type 2 diabetes mellitus.

METHODS

A systematic literature search up to April 2021 was performed, and 8 studies included 61,661 subjects with type 2 diabetes mellitus at the start of the study, 29,034 of them were using glucagon-like peptide-1 receptor agonists and 32,627 were given a placebo. They reported on relationships between the effects of glucagon-like peptide-1 receptor agonists compared to placebo on mortality rates, cardiovascular, renal and ophthalmic outcomes in subjects with type 2 diabetes mellitus. We calculated the odds ratio (OR) with 95% confidence intervals (CIs) to assess the effects of glucagon-like peptide-1 receptor agonists compared to placebo on the listed outcomes on subjects with type 2 diabetes mellitus, using the dichotomous method with a random or fixed-effect model.

RESULTS

The use of glucagon-like peptide-1 receptor agonists was associated with significantly lowered all-cause mortality (OR, 0.76; 95% CI, 0.65-0.89, p < 0.001), cardiovascular deaths (OR, 0.87; 95% CI, 0.81-0.94, p < 0.001), myocardial infarctions (OR, 0.92; 95% CI, 0.85-0.98, p = 0.01), strokes (OR, 0.81; 95% CI, 0.74--0.90, p < 0.001), hospital admissions owing to heart failure (OR, 0.91; 95% CI, 0.83-1.00, p = 0.04) and renal events (OR, 0.83; 95% CI, 0.77-0.89, p < 0.001) compared to placebo in subjects with type 2 diabetes mellitus. However, glucagon-like peptide-1 receptor agonists had significantly higher ophthalmic events (OR, 1.15; 95% CI, 1.04-1.29, p = 0.009) compared to placebo in subjects with type 2 diabetes mellitus.

WHAT IS NEW AND CONCLUSION

Glucagon-like peptide-1 receptor agonists may have a lower risk of all-cause mortality, cardiovascular death, myocardial infarction, stroke, hospital admission owing to heart failure and renal events compared to placebo in subjects with type 2 diabetes mellitus. However, they have significantly higher ophthalmic events compared to placebo in subjects with type 2 diabetes mellitus. Further studies are required to validate these findings.

Profiles of Intraday Glucose in Type 2 Diabetes and Their Association with Complications: An Analysis of Continuous Glucose Monitoring Data

Aims: To identify profiles of type 2 diabetes from continuous glucose monitoring (CGM) data using ambulatory glucose profile (AGP) indicators and examine the association with prevalent complications. Methods: Two weeks of CGM data, collected between 2015 and 2019, from 5901 adult type 2 diabetes patients were retrieved from a clinical database in Chennai, India. Non-negative matrix factorization was used to identify profiles as per AGP indicators. The association of profiles with existing complications was examined using multinomial and logistic regressions adjusted for glycated hemoglobin (HbA1c; %), sex, age at onset, and duration of diabetes. Results: Three profiles of glycemic variability (GV) were identified based on CGM data-Profile 1 ["TIR Profile"] (n = 2271), Profile 2 ["Hypo"] (n = 1471), and Profile 3 ["Hyper"] (n = 2159). Compared with time in range (TIR) profile, those belonging to Hyper had higher mean fasting plasma glucose (202.9 vs. 167.1, mg/dL), 2-h postprandial plasma glucose (302.1 vs. 255.6, mg/dL), and HbA1c (9.7 vs. 8.6; %). Both "Hypo profile" and "Hyper profile" had higher odds of nonproliferative diabetic retinopathy ("Hypo": 1.44, 1.20-1.73; "Hyper": 1.33, 1.11-1.58), macroalbuminuria ("Hypo": 1.58, 1.25-1.98; "Hyper": 1.37, 1.10-1.71), and diabetic kidney disease (DKD; "Hypo": 1.65, 1.18-2.31; "Hyper": 1.88, 1.37-2.58), compared with "TIR profile." Those in "Hypo profile" (vs. "TIR profile") had higher odds of proliferative diabetic retinopathy (PDR; 2.84, 1.65-2.88). Conclusions: We have identified three profiles of GV from CGM data. While both "Hypo profile" and "Hyper profile" had higher odds of prevalent DKD compared with "TIR profile," "Hypo profile" had higher odds of PDR. Our study emphasizes the clinical importance of recognizing and treating hypoglycemia (which is often unrecognized without CGM) in patients with type 2 Diabetes Mellitus.

Safety of Semaglutide

The glucagon-like peptide-1 receptor agonist (GLP-1RA) semaglutide is the most recently approved agent of this drug class, and the only GLP-1RA currently available as both subcutaneous and oral formulation. While GLP-1RAs effectively improve glycemic control and cause weight loss, potential safety concerns have arisen over the years. For semaglutide, such concerns have been addressed in the extensive phase 3 registration trials including cardiovascular outcome trials for both subcutaneous (SUSTAIN: Semaglutide Unabated Sustainability in Treatment of Type 2 Diabetes) and oral (PIONEER: Peptide InnOvatioN for the Early diabEtes tReatment) semaglutide and are being studied in further trials and registries, including real world data studies. In the current review we discuss the occurrence of adverse events associated with semaglutide focusing on hypoglycemia, gastrointestinal side effects, pancreatic safety (pancreatitis and pancreatic cancer), thyroid cancer, gallbladder events, cardiovascular aspects, acute kidney injury, diabetic retinopathy (DRP) complications and injection-site and allergic reactions and where available, we highlight potential underlying mechanisms. Furthermore, we discuss whether effects are specific for semaglutide or a class effect. We conclude that semaglutide induces mostly mild-to-moderate and transient gastrointestinal disturbances and increases the risk of biliary disease (cholelithiasis). No unexpected safety issues have arisen to date, and the established safety profile for semaglutide is similar to that of other GLP-1RAs where definitive conclusions for pancreatic and thyroid cancer cannot be drawn at this point due to low incidence of these conditions. Due to its potent glucose-lowering effect, patients at risk for deterioration of existing DRP should be carefully monitored if treated with semaglutide, particularly if also treated with insulin. Given the beneficial metabolic and cardiovascular actions of semaglutide, and the low risk for severe adverse events, semaglutide has an overall favorable risk/benefit profile for patient with type 2 diabetes.

Comparing the use of individual and composite terms to evaluate adverse drug event disproportionality: a focus on glucagon-like peptide-1 receptor agonists and diabetic retinopathy

Background: The SUSTAIN-6 trial showed significantly higher rates of retinopathy complications in the semaglutide group compared to placebo. Observational studies have not consistently corroborated this finding, raising questions about the appropriateness of composite variables and whether the relationship exists across the entire drug class or is limited to individual glucagon-like peptide 1 agonists (GLP-1RAs). The study objective was to evaluate the difference between using individual and composite terms to assess associations between GLP-1RAs and diabetic retinopathy events.Research Design and Methods: Reports from the US Food and Drug Administration Adverse Event Reporting System were utilized to examine relationships between GLP-1RAs and diabetic retinopathy events. A disproportionality analysis was conducted using the proportional reporting ratio.Results: Four GLP-1RAs demonstrated signals for diabetic retinopathy events. The GLP-1RA drug class had four diabetic retinopathy signals. Only semaglutide had a signal for the composite diabetic retinopathy outcome. The GLP-1RA drug class and the composite diabetic retinopathy outcome did not meet the PRR signal thresholds.Conclusions: The use of drug class level and composite outcome variables may mask diabetic retinopathy signals in comparison to individual drug assessments. Our results support the SUSTAIN-6 trial findings and suggest an association between four GLP-1RAs and diabetic retinopathy events.

An Overview of Similarities and Differences in Metabolic Actions and Effects of Central Nervous System Between Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RAs) and Sodium Glucose Co-Transporter-2 Inhibitors (SGLT-2is)

GLP-1 receptor agonists (GLP-1RAs) and SGLT-2 inhibitors (SGLT-2is) are novel antidiabetic medications associated with considerable cardiovascular benefits therapying treatment of diabetic patients. GLP-1 exhibits atherosclerosis resistance, whereas SGLT-2i acts to ameliorate the neuroendocrine state in the patients with chronic heart failure. Despite their distinct modes of action, both factors share pathways by regulating the central nervous system (CNS). While numerous preclinical and clinical studies have demonstrated that GLP-1 can access various nuclei associated with energy homeostasis and hedonic eating in the CNS via blood-brain barrier (BBB), research on the activity of SGLT-2is remains limited. In our previous studies, we demonstrated that both GLP-1 receptor agonists (GLP-1RAs) liraglutide and exenatide, as well as an SGLT-2i, dapagliflozin, could activate various nuclei and pathways in the CNS of Sprague Dawley (SD) rats and C57BL/6 mice, respectively. Moreover, our results revealed similarities and differences in neural pathways, which possibly regulated different metabolic effects of GLP-1RA and SGLT-2i via sympathetic and parasympathetic systems in the CNS, such as feeding, blood glucose regulation and cardiovascular activities (arterial blood pressure and heart rate control). In the present article, we extensively discuss recent preclinical studies on the effects of GLP-1RAs and SGLT-2is on the CNS actions, with the aim of providing a theoretical explanation on their mechanism of action in improvement of the macro-cardiovascular risk and reducing incidence of diabetic complications. Overall, these findings are expected to guide future drug design approaches.

A comprehensive understanding about the pharmacological effect of diallyl disulfide other than its anti-carcinogenic activities

Diallyl disulfide (DADS), an oil-soluble sulfur compound that is responsible for the biological effects of garlic, displays numerous biological activities, among which its anti-cancer activities are the most famous ones. In recent years, the pharmacological effects of DADS other than its anti-carcinogenic activities have attracted numerous attentions. For example, it has been reported that DADS can prevent the microglia-mediated neuroinflammatory response and depression-like behaviors in mice. In the cardiovascular system, DADS administration was found to ameliorate the isoproterenol- or streptozotocin-induced cardiac dysfunction via the activation of the nuclear factor E2-related factor 2 (Nrf2) and insulin-like growth factor (IGF)-phosphatidylinositol-3-kinase (PI3K)-protein kinase B (Akt) signaling. DADS administration can also produce neuroprotective effects in animal models of Alzheimer's disease and protect the heart, endothelium, liver, lung, and kidney against cellular or tissue damages induced by various toxic factors, such as the oxidized-low density lipoprotein (ox-LDL), carbon tetrachloride (CCl₄), ethanol, acetaminophen, Cis-Diammine Dichloroplatinum (CisPt), and gentamicin. The major mechanisms of action of DADS in disease prevention and/or treatment include inhibition of inflammation, oxidative stress, and cellular apoptosis. Mechanisms, including the activation of Akt, extracellular signal-regulated kinase 1/2 (ERK1/2), protein kinase A (PKA), and cyclic adenosine monophosphate-response element binding protein (CREB) and the inhibition of histone deacetylases (HDACs), can also mediate the cellular protective effects of DADS in different tissues and organs. In this review, we summarize and discuss the pharmacological effects of DADS other than its anti-carcinogenic activities, aiming to reveal more possibilities for DADS in disease prevention and/or treatment.

The treament of hyperglycemia in acute ischemic stroke with incretin-based drugs

Stroke is a major cause of mortality and morbidity worldwide. Considerable experimental and clinical evidence suggests that both diabetes mellitus (DM) and post-stroke hyperglycemia are associated with increased mortality rate and worsened clinical conditions in acute ischemic stroke (AIS) patients. Insulin treatment does not seem to provide convincing benefits for these patients, therefore prompting a change of strategy. The selective agonists of Glucagon-Like Peptide-1 Receptors (GLP-1Ras) and the Inhibitors of Dipeptidyl Peptidase-IV (DPP-IVIs, gliptins) are two newer classes of glucose-lowering drugs used for the treatment of DM. This review examines in detail the rationale for their development and the physicochemical, pharmacokinetic and pharmacodynamic properties and clinical activities. Emphasis will be placed on their neuroprotective effects at cellular and molecular levels in experimental models of acute cerebral ischemia. In perspective, an adequate basis does exist for a novel therapeutic approach to hyperglycemia in AIS patients through the additive treatment with GLP-1Ras plus DPP-IVIs.

Invited review. Series: Implications of the recent CVOTs in type 2 diabetes: Which patients for GLP-1RA or SGLT-2 inhibitor?

Large cardiovascular outcome trials (CVOTs) have lent support to a cardiovascular protection with the use of SGLT2-inhibitors (SGLT2is) and GLP1-Receptor Agonists (GLP1-RAs) in subjects with type 2 diabetes. These two classes of novel glucose lowering agents have been shown to have a similar effect on the risk reduction of Major Adverse Cardiovascular Events (MACE: nonfatal myocardial infarction, nonfatal stroke, cardiovascular mortality). Nonetheless, they may not be simply interchangeable. Rather, careful evaluation of all the results of CVOTs leads identification of different effects that may allow profiling of the ideal individuals with T2DM who may benefit most from the use of one or the other class of agents. These differences include effect on heart failure, stroke and diabetic kidney disease that have prompt recent guidelines and recommendation for the treatment of type 2 diabetes to suggest the preferential use of SGLT2is in those with evidence of heart failure and impaired kidney function, while both SGLT2i and GLP1-RAs with proven effect could be use in those with prevalent atherosclerotic cardiovascular disease. This review discusses all these elements of differentiation along with others that in the future may help establishing the best cardiorenal benefit for individuals with T2DM.

Endothelial Dysfunction in Diabetic Retinopathy

Diabetic retinopathy (DR) is a diabetic complication which affects retinal function and results in severe loss of vision and relevant retinal diseases. Retinal vascular dysfunction caused by multifactors, such as advanced glycosylation end products and receptors, pro-inflammatory cytokines and chemokines, proliferator-activated receptor-γ disruption, growth factors, oxidative stress, and microRNA. These factors promote retinal endothelial dysfunction, which results in the development of DR. In this review, we summarize the contributors in the pathophysiology of DR for a better understanding of the molecular and cellular mechanism in the development of DR with a special emphasis on retinal endothelial dysfunction.