Effect of ipragliflozin, an SGLT2 inhibitor, on progression of diabetic microvascular complications in spontaneously diabetic Torii fatty rats

Ranibizumab with luseogliflozin in type 2 diabetes with diabetic macular oedema: A randomised clinical trial

AIMS

Anti-vascular endothelial growth factor (VEGF) therapy is the standard treatment for diabetic macular oedema (DMO); however, unmet needs remain. This study aimed to assess the effectiveness of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in treating DMO.

MATERIALS AND METHODS

This multicentre randomised open-label trial included 60 patients with DMO who were eligible for anti-VEGF therapy. Patients were randomised to receive luseogliflozin or glimepiride. Ranibizumab was administered initially to the target eye, with additional doses per protocol. The number of ranibizumab doses up to week 48, and re-admission rates were evaluated. Fellow eye injections were also assessed.

RESULTS

Sixty participants, mostly with diabetic retinopathy and half previously treated with anti-VEGF therapy, were included. SGLT2i and sulfonylurea (SU) groups achieved equivalent glycated haemoglobin, central retinal thickness (CRT), and best-corrected visual acuity improvements. Injection frequency for the target eye was similar between groups (SGLT2i vs. SU: 3.9 ± 0.7 vs. 4.7 ± 0.7 times, p = 0.36). Re-administration rates were decreased significantly after the fourth injection in the SGLT2i group (p = 0.030, hazard ratio: 0.45, 95% confidence interval: 0.22-0.92). Fellow eyes in the SGLT2i group showed significant CRT reduction and fewer injections compared with those in the SU group (1.3 ± 0.6 vs. 3.4 ± 0.8, p = 0.016).

CONCLUSIONS

Although the overall number of anti-VEGF injections in the target eye showed no significant difference, some patients responded favourably to SGLT2i and required fewer injections. The reduction in fellow eye injections suggests SGLT2i's efficacy in treating early-stage DMO.

TRIAL REGISTRATION

University Hospital Medical Information Network Clinical Trial Registry (UMIN000033961); Japan Registry of Clinical Trials (jRCTs031180210).

An update on ocular effects of antidiabetic medications

The global increase in the prevalence of type 2 diabetes has led to the development and implementation of new classes of antidiabetic medications, introducing advanced therapeutic options for the management of the disease. These new medications, though primarily designed to regulate blood glucose levels, also have applications in weight management, potentially transforming the current approaches to diabetes treatment. Newer medications, however, have ophthalmic side effects with controversies in trials and real-life data. We comprehensively assessed the ocular benefits and adverse effects of traditional and newer-generation anti-diabetic drugs. Our primary focus is on how these newer medications affect the stage of diabetic retinopathy. Additionally, we explore the associations between these medications and other ocular conditions, including age-related macular degeneration, glaucoma, orbital conditions, and diseases impacting the ocular surface. Furthermore, we provide contextual background by discussing the ocular effects of traditional anti-diabetic drugs.

The dichloromethane fraction from Calotropis gigantea (L.) dryand. Stem bark extract prevents liver cancer in SDT rats with insulin-independent diabetes mellitus

ETHNOPHARMACOLOGICAL RELEVANCE

Calotropis gigantea (L.) Dryand. (C. gigantea) is a traditional medicinal plant, recognized for its effectiveness in managing diabetes, along with its notable antioxidant, anti-inflammatory, and anticancer properties. Type II diabetes mellitus (T2DM) is characterized by chronic metabolic disorders associated with an elevated risk of hepatocellular carcinoma (HCC) due to hyperglycemia and impaired insulin response. The scientific validation of C. gigantea's ethnopharmacological efficacy offers advantages in alleviating cancer progression in T2DM complications, enriching existing knowledge and potentially aiding future clinical cancer treatments.

AIM

This study aimed to investigate the preventive potential of the dichloromethane fraction of C. gigantea stem bark extract (CGDCM) against diethylnitrosamine (DEN)-induced HCC in T2DM rats, aiming to reduce cancer incidence associated with diabetes while validating C. gigantea's ethnopharmacological efficacy.

MATERIALS AND METHODS

Spontaneously Diabetic Torii (SDT) rats were administered DEN to induce HCC (SDT-DEN-VEH), followed by treatment with CGDCM. Metformin was used as a positive control (SDT-DEN-MET). All the treatments were administered for 10 weeks after the initial DEN injection. Diabetes-related parameters, including serum levels of glucose, insulin, and glycosylated hemoglobin (HbA1c), as well as liver function enzymes (aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and gamma-glutamyl transferase), were quantified. Serum inflammation biomarkers interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were evaluated. Liver tissue samples were analyzed for inflammation protein expression (IL-6, TNF-α, transforming growth factor-β1 (TGF-β1), and α-smooth muscle actin (α-SMA)). Histopathological evaluation was performed to assess hepatic necrosis, inflammation, and fibrosis. Liver cell proliferation was determined using immunohistochemistry for Ki-67 expression.

RESULTS

Rats with SDT-DEN-induced HCC treated with CGDCM exhibited reduced serum glucose levels, elevated insulin levels, and decreased HbA1c levels. CGDCM treatment also reduced elevated hepatic IL-6, TNF-α, TGF-β1, and α-SMA levels in SDT-DEN-VEH rats. Additionally, CGDCM treatment prevented hepatocyte damage, fibrosis, and cell proliferation. No adverse effects on normal organs were observed with CGDCM treatment, suggesting its safety for the treatment of HCC complications associated with diabetes. Additionally, the absence of adverse effects in SD rats treated with CGDCM at 2.5 mg/kg further supports the notion of its safe usage.

CONCLUSIONS

These findings suggest that C. gigantea stem bark extract exerts preventive effects against the development of HCC complications in patients with T2DM, expanding the potential benefits of its ethnopharmacological advantages.

Comparison of the Risk of Diabetic Retinopathy Between Sodium-Glucose Cotransporter-2 Inhibitors and Dipeptidyl Peptidase-4 Inhibitors in Patients with Type 2 Diabetes Mellitus in Japan: A Retrospective Analysis of Real-World Data

INTRODUCTION

Diabetic retinopathy (DR), a microvascular complication of type 2 diabetes mellitus (T2DM), is a leading cause of blindness and has detrimental effects on patients' quality of life. We compared the risk of DR diagnosis with sodium-glucose cotransporter-2 inhibitors (SGLT2i) versus dipeptidyl peptidase-4 inhibitors (DPP-4i) in patients with T2DM in Japan.

METHODS

This Japanese retrospective cohort study used the JMDC Claims Database (data collected from January 2015 to September 2022). Patients with T2DM and no record of microvascular or macrovascular diseases who were newly treated with an SGLT2i (23,061 patients) or a DPP-4i (53,986 patients) were matched 1:1 using propensity score (10,166 per matched group). Incidence rates (IRs) and cumulative IRs of DR diagnosis were calculated for each treatment group; hazard ratio (HR) and its 95% confidence interval (CI) were calculated using Cox proportional hazard models to compare the risk between the groups.

RESULTS

The IR of DR diagnosis was 46.23 and 57.12 per 1000 person-years in the SGLT2i and DPP-4i groups, respectively, with a significantly lower risk in the SGLT2i group than in the DPP-4i group (HR 0.83, 95% CI 0.75-0.92, P = 0.0003).

CONCLUSIONS

In this study, the risk of DR diagnosis was lower with SGLT2i compared with DPP-4i in patients with T2DM without microvascular and macrovascular diseases in Japan. Findings suggest that early SGLT2i treatment may be beneficial in preventing DR development in early-stage T2DM. Graphical abstract available for this article.

Comparative Effectiveness of Glucagon-Like Peptide-1 Receptor Agonists, Sodium-Glucose Cotransporter 2 Inhibitors, Dipeptidyl Peptidase-4 Inhibitors, and Sulfonylureas for Sight-Threatening Diabetic Retinopathy

OBJECTIVE

To investigate whether the choice of glucose-lowering agent for type 2 diabetes (T2D) impacts a patient's risk of developing sight-threatening diabetic retinopathy complications.

DESIGN

Retrospective observational database study emulating an idealized target trial.

SUBJECTS

Adult (≥21 years) enrollees in United States commercial, Medicare Advantage, and Medicare fee-for-service plans from January 1, 2014, to December 31, 2021, with T2D and moderate cardiovascular disease (CVD) risk who had no baseline history of advanced diabetic retinal complications, initiating treatment with glucagon-like peptide-1 receptor agonists (GLP-1 RA), sodium-glucose cotransporter 2 inhibitors (SGLT2i), dipeptidyl peptidase-4 inhibitors (DPP-4i), and sulfonylureas.

METHODS

We used inverse propensity scoring weights in time-to-event Cox proportional hazards models.

MAIN OUTCOME MEASURES

Treatment for either diabetic macular edema or proliferative diabetic retinopathy.

RESULTS

The final study population included 371 698 patients, of whom 42 265 initiated GLP-1 RA, 53 476 initiated SGLT2i, 78 444 initiated DPP-4i, and 197 513 initiated sulfonylurea agents. The probability of treatment for sight-threatening retinopathy within 2 and 5 years was 0.3% and 0.7% for patients initiating SGLT2i (median follow-up 830 [interquartile range (IQR), 343-1401] days), 0.4% and 1.0% for GLP-1 RA (669 [IQR, 256-1167] days), 0.4% and 0.9% for DPP-4i (1263 [IQR, 688-1938] days), and 0.5% and 1.2% for sulfonylurea (1223 [IQR, 662-1879] days). Sodium-glucose cotransporter 2 inhibitors use was associated with a lower risk of treatment for sight-threatening retinopathy compared with all other medication classes, including GLP-1 RA (hazard ratio [HR], 0.73; 95% confidence interval [CI], 0.55-0.97), DPP-4i (HR, 0.79; 95% CI, 0.64-0.97), and sulfonylurea (HR, 0.61; 95% CI, 0.50-0.74). Glucagon-like peptide-1 receptor agonists use was associated with a similar risk of sight-threatening retinopathy as DPP-4i (HR, 1.07; 95% CI, 0.85-1.35) and sulfonylurea (HR, 0.83; 95% CI, 0.67-1.03).

CONCLUSIONS

Sodium-glucose cotransporter 2 inhibitors use was associated with a lower risk of sight-threatening diabetic retinopathy among adults with T2D and moderate CVD risk compared with other glucose-lowering therapies. Glucagon-like peptide-1 receptor agonists do not confer increased retinal risk, relative to DPP-4i and sulfonylurea medications.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Sodium-glucose cotransporter 2 inhibitor therapy reduces the administration frequency of steroid injection in patients with diabetic macular edema: A cohort study using the Japanese health insurance claims database

AIMS/INTRODUCTION

Severe diabetic macular edema (DME) is often resistant to anti-vascular endothelial growth factor therapy. Steroids are particularly effective at reducing edema by suppressing inflammation; they are also used as an alternative to expensive anti-vascular endothelial growth factor therapy in some patients. Therefore, the use of steroids in DME reflects an unmet need for anti-vascular endothelial growth factor therapy. Notably, triamcinolone acetonide (TA) injections are widely used in Japan. Here, we evaluated the frequency of TA as an indicator of the efficacy of sodium-glucose cotransporter 2 inhibitors (SGLT2is) in DME treatment using a health insurance claims database.

MATERIALS AND METHODS

In this cohort study, we retrospectively analyzed the health insurance claims data of 11 million Japanese individuals from 2005 to 2019. The frequency and duration of TA injection after the initiation of SGLT2is or other antidiabetic drugs were analyzed.

RESULTS

Among the 2,412 matched patients with DME, the incidence rate of TA injection was 63.8 times per 1,000 person-years in SGLT2i users and 94.9 times per 1,000 person-years in non-users. SGLT2is reduced the risk for the first (P = 0.0024, hazard ratio 0.66, 95% confidence interval 0.50-0.87), second (P = 0.0019, hazard ratio 0.53, 95% confidence interval 0.35-0.80) and third TA (P = 0.0053, hazard ratio 0.44, 95% confidence interval 0.25-0.80) injections. A subanalysis of each baseline characteristic of the patients showed that SGLT2is were effective regardless of the background factors.

CONCLUSIONS

The use of SGLT2is reduced the frequency of TA injection in patients with DME. Therefore, SGLT2i therapy might be a novel, noninvasive and low-cost adjunctive therapy for DME.

Endothelial dysfunction in vascular complications of diabetes: a comprehensive review of mechanisms and implications

Diabetic vascular complications are prevalent and severe among diabetic patients, profoundly affecting both their quality of life and long-term prospects. These complications can be classified into macrovascular and microvascular complications. Under the impact of risk factors such as elevated blood glucose, blood pressure, and cholesterol lipids, the vascular endothelium undergoes endothelial dysfunction, characterized by increased inflammation and oxidative stress, decreased NO biosynthesis, endothelial-mesenchymal transition, senescence, and even cell death. These processes will ultimately lead to macrovascular and microvascular diseases, with macrovascular diseases mainly characterized by atherosclerosis (AS) and microvascular diseases mainly characterized by thickening of the basement membrane. It further indicates a primary contributor to the elevated morbidity and mortality observed in individuals with diabetes. In this review, we will delve into the intricate mechanisms that drive endothelial dysfunction during diabetes progression and its associated vascular complications. Furthermore, we will outline various pharmacotherapies targeting diabetic endothelial dysfunction in the hope of accelerating effective therapeutic drug discovery for early control of diabetes and its vascular complications.

Glucose transport, transporters and metabolism in diabetic retinopathy

Diabetic retinopathy (DR) is the most common reason for blindness in working-age individuals globally. Prolonged high blood glucose is a main causative factor for DR development, and glucose transport is prerequisite for the disturbances in DR caused by hyperglycemia. Glucose transport is mediated by its transporters, including the facilitated transporters (glucose transporter, GLUTs), the "active" glucose transporters (sodium-dependent glucose transporters, SGLTs), and the SLC50 family of uniporters (sugars will eventually be exported transporters, SWEETs). Glucose transport across the blood-retinal barrier (BRB) is crucial for nourishing the neuronal retina in the context of retinal physiology. This physiological process primarily relies on GLUTs and SGLTs, which mediate the glucose transportation across both the cell membrane of retinal capillary endothelial cells and the retinal pigment epithelium (RPE). Under diabetic conditions, increased accumulation of extracellular glucose enhances the retinal cellular glucose uptake and metabolism via both glycolysis and glycolytic side branches, which activates several biochemical pathways, including the protein kinase C (PKC), advanced glycation end-products (AGEs), polyol pathway and hexosamine biosynthetic pathway (HBP). These activated biochemical pathways further increase the production of reactive oxygen species (ROS), leading to oxidative stress and activation of Poly (ADP-ribose) polymerase (PARP). The activated PARP further affects all the cellular components in the retina, and finally resulting in microangiopathy, neurodegeneration and low-to-moderate grade inflammation in DR. This review aims to discuss the changes of glucose transport, glucose transporters, as well as its metabolism in DR, which influences the retinal neurovascular unit (NVU) and implies the possible therapeutic strategies for treating DR.

Protective Effect of Pemafibrate Treatment against Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats

Diabetic retinopathy (DR) can cause visual impairment and blindness, and the increasing global prevalence of diabetes underscores the need for effective therapies to prevent and treat DR. Therefore, this study aimed to evaluate the protective effect of pemafibrate treatment against DR, using a Spontaneously Diabetic Torii (SDT) fatty rat model of obese type 2 diabetes. SDT fatty rats were fed either a diet supplemented with pemafibrate (0.3 mg/kg/day) for 16 weeks, starting at 8 weeks of age (Pf SDT fatty: study group), or normal chow (SDT fatty: controls). Normal chow was provided to Sprague-Dawley (SD) rats (SD: normal controls). Electroretinography (ERG) was performed at 8 and 24 weeks of age to evaluate the retinal neural function. After sacrifice, retinal thickness, number of retinal folds, and choroidal thickness were evaluated, and immunostaining was performed for aquaporin-4 (AQP4). No significant differences were noted in food consumption, body weight, or blood glucose level after pemafibrate administration. Triglyceride levels were reduced, and high-density lipoprotein cholesterol levels were increased. Extension of oscillatory potential (OP)1 and OP3 waves on ERG was suppressed in the Pf SDT fatty group. Retinal thickness at 1,500 microns from the optic disc improved in the Pf SDT fatty group. No significant improvements were noted in choroidal thickness or number of retinal folds. Quantitative analyses showed that AQP4-positive regions in the retinas were significantly larger in the Pf SDT fatty group than in the SDT fatty group. The findings suggest that pemafibrate treatment can exert protective effects against DR.

Recent advances in the treatment and delivery system of diabetic retinopathy

Diabetic retinopathy (DR) is a highly tissue-specific neurovascular complication of type 1 and type 2 diabetes mellitus and is among the leading causes of blindness worldwide. Pathophysiological changes in DR encompass neurodegeneration, inflammation, and oxidative stress. Current treatments for DR, including anti-vascular endothelial growth factor, steroids, laser photocoagulation, and vitrectomy have limitations and adverse reactions, necessitating the exploration of novel treatment strategies. This review aims to summarize the current pathophysiology, therapeutic approaches, and available drug-delivery methods for treating DR, and discuss their respective development potentials. Recent research indicates the efficacy of novel receptor inhibitors and agonists, such as aldose reductase inhibitors, angiotensin-converting enzyme inhibitors, peroxisome proliferator-activated receptor alpha agonists, and novel drugs in delaying DR. Furthermore, with continuous advancements in nanotechnology, a new form of drug delivery has been developed that can address certain limitations of clinical drug therapy, such as low solubility and poor penetration. This review serves as a theoretical foundation for future research on DR treatment. While highlighting promising therapeutic targets, it underscores the need for continuous exploration to enhance our understanding of DR pathogenesis. The limitations of current treatments and the potential for future advancements emphasize the importance of ongoing research in this field.

Risk of Diabetic Retinopathy in Patients With Type 2 Diabetes After SGLT-2 Inhibitors: A Nationwide Population Cohort Study

Diabetic retinopathy (DR) accounts for 80% of cases of vision loss in patients with type 2 diabetes mellitus (T2DM). Interventional treatments are only indicated in advanced DR and are ineffective in some patients. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) are used to attenuate T2DM-associated cardiovascular complications. We conducted the cohort study to investigate the effect of SGLT2is on DR development. Data (May 2016-December 2018) obtained from the Taiwan National Health Insurance Research Database were analyzed in this nationwide retrospective cohort study. After propensity score matching, a total of 31,764 patients receiving SGLT2is and another 31,764 patients receiving dipeptidyl peptidase 4 inhibitors (DPP4is) were included in this study. Multiple Cox proportional-hazards regression models were used to evaluate DR risk. Overall DR incidence among SGLT2i or DPP4i users was 10.9 or 15.6 per 10,000 patient-years, respectively. After covariate adjustment, DR (both early and late stage) risk was substantially lower in SGLT2i users (adjusted hazard ratio: 0.68, 95% confidence interval: 0.6-0.78) than in DPP4i users. DR risk appears to be considerably lower in SGLT2i users than in DPP4i users. Glycemic control measurement with HbA1C level was unavailable in this claim database.

A Review of Recent Pharmacological Advances in the Management of Diabetes-Associated Peripheral Neuropathy

Diabetic peripheral neuropathy is a common complication of longstanding diabetes mellitus. These neuropathies can present in various forms, and with the increasing prevalence of diabetes mellitus, a subsequent increase in peripheral neuropathy cases has been noted. Peripheral neuropathy has a significant societal and economic burden, with patients requiring concomitant medication and often experiencing a decline in their quality of life. There is currently a wide variety of pharmacological interventions, including serotonin norepinephrine reuptake inhibitors, gapentanoids, sodium channel blockers, and tricyclic antidepressants. These medications will be discussed, as well as their respective efficacies. Recent advances in the treatment of diabetes mellitus with incretin system-modulating drugs, specifically glucagon-like peptide-1 agonists, have been promising, and their potential implication in the treatment of peripheral diabetic neuropathy is discussed in this review.

Diabetic patients with and without sodium-glucose cotransporter-2 inhibitors use and cataract risk: real-world observational investigation

PURPOSE

We tried to define the association of type 2 diabetes mellitus (T2DM) patients with and without sodium-glucose cotransporter-2 inhibitors (SGLT2I) use and incident cataract using nationwide data in Taiwan.

METHODS

In a Cox proportional hazards regression model, we estimated the hazard ratios (HR) and 95% confidence intervals (95% CI). We considered risk factors for variables of sex, age, comorbidities and medications that we adjusted in multivariable Cox model.

RESULTS

We identified 20,768 T2DM patients in this study; 10,384 patients in the SGLT2I cohort, and 10,384 controls in the non-SGLT2I cohort. Compared with the T2DM patients without SGLT2I, T2DM patients using SGLT2I had a 2.04-fold increased risk of cataract, after adjustment by sex, age, comorbidities and medications.

CONCLUSION

Increased risk of cataract among diabetic patients who took SGLT2I was found in this study.

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.

Dry eye disease in patients with type II diabetes mellitus: A retrospective, population-based cohort study in Taiwan

Purpose

To investigate the risk and protective factors of dry eye disease (DED) in patients with type II diabetes mellitus (DM).

Design

A retrospective cohort study using Chang- Gung research database collecting data from 2005 to 2020.

Methods

Patients with type II DM were included, and those with previous ocular diseases were excluded. Ten thousand twenty nine developed DED (DED group), and 142,491 didn't (non-DED group). The possible risk and protective factors were compared and analyzed using the logistic regression model.

Results

A majority of the DED group were female with significantly higher initial and average glycated hemoglobin levels, and higher incidence of diabetic neuropathy and retinopathy. In conditional logistic regression model, advanced age was a risk factor. After adjusting for sex, age, and DM duration; average glycated hemoglobin level, diabetic neuropathy, retinopathy, and nephropathy with eGFR 30 ~ 59 and intravitreal injection, vitrectomy, pan-retinal photocoagulation, and cataract surgery were contributing factors of DED. Considering antihyperglycemic agents, DPP4 inhibitor, SGLT2 inhibitor, GLP-1 agonist, and insulin monotherapy and dual medications combining any two of the aforementioned agents were protective factors against DED compared with metformin alone. In the monotherapy group, SLGT2 inhibitor had the lowest odds ratio, followed by GLP1 agonist, DPP4 inhibitor, and insulin.

Conclusions

DED in patients with DM is associated with female sex, advanced age, poor diabetic control, microvascular complications and receiving ocular procedures. GLP-1 agonist, SGLT-2 inhibitor, DPP4 inhibitor, and insulin are superior to metformin alone in preventing DM-related DED. A prospective randomized control trial is warranted to clarify our results.

The association between the use of sodium glucose cotransporter 2 inhibitor and the risk of diabetic retinopathy and other eye disorders: a systematic review and meta-analysis

OBJECTIVE

To assess the association between the use of sodium-glucose cotransporter 2 inhibitor (SGLT2i) and the incidence of diabetic retinopathy (DR).

RESEARCH DESIGN AND METHODS

Pubmed, Medline, Embase, the Cochrane Central Register of Controlled Trials and Clinicaltrial.gov were searched from inception to October 2021. Randomized controlled trials (RCTs) with reports of incidence of DR and other eye disorders between SGLT2i users and non-SGLT2i users with type 2 diabetes mellitus were included.

RESULTS

In general, the incidences of DR were comparable between SGLT2i users and non-SGLT2i users (OR=0.80, 95%CI 0.61 to 1.06, P=0.12). However, compared with non-SGLT2i users, the incidence of DR was significantly reduced in SGLT2i users with diabetes duration less than 10 years (OR=0.32, 95%CI 0.13 to 0.76, P=0.01). Weight reduction in SGLT2i users was associated with the decreased risk of retinal detachment. Moreover, longer study duration was associated with lower incidence of cataract and retinal vasculopathy in SGLT2i users.

CONCLUSIONS

In general, the use of SGLT2i was not associated with the incidence of DR. However, a reduced risk of DR was observed in SGLT2i users with diabetes duration less than 10 years. An early initiation of SGLT2i might be more likely to provide with ocular benefits.

Dapagliflozin protects neural and vascular dysfunction of the retina in diabetes

INTRODUCTION

Dapagliflozin, a sodium-glucose transporter inhibitor, effectively reduces blood glucose and is indicated for individuals with kidney diseases and cardiovascular disorders. In this study, we further expand the therapeutic benefit of dapagliflozin in the neural and vascular retina, with the potential to effectively manage diabetic retinopathy (DR), the most common complication of diabetes.

RESEARCH DESIGN AND METHODS

Db/db mice, an animal model of type 2 diabetes, were treated with dapagliflozin orally, and the electroretinogram (ERG) response and acellular capillary numbers were assessed. Messenger RNA levels of inflammatory cytokines were studied using real-time quantitative (q)PCR. We assessed endothelial cell migration in a scratch wound assay and retinal glucose uptake using human retinal endothelial cells.

RESULTS

The dapagliflozin treatment improved the ERG b-wave amplitude and decreased acellular capillary numbers. The scratch wound assay demonstrated a reduction in wound closure after dapagliflozin treatment. Retinal glucose uptake reduced after dapagliflozin treatment compared with the respective controls.

CONCLUSIONS

Our studies suggest that dapagliflozin treatment effectively corrects neural and vascular dysfunction of the retina in diabetes. This effect is mediated by a decrease in inflammation and improved glycemic control. In addition, dapagliflozin exhibits decreased wound healing and glucose uptake, which could benefit the retina. Thus, dapagliflozin could be helpful in the management of DR, with multimodal therapeutic effects.

Determining the role of SGLT2 inhibition with Empagliflozin in the development of diabetic retinopathy

Diabetes mellitus is a chronic metabolic disease that occurs when the pancreas is not producing enough insulin or when the insulin that it does produce is not able to be used effectively in the body. This results in hyperglycemia and if the blood sugars are not controlled, then it can lead to serious damage of various body systems, especially the nerves and the blood vessels. Uncontrolled diabetes is a major cause of kidney failure, heart attacks, stroke and amputation. One of the most devastating complications for patients is diabetic retinopathy (DR) which represents the leading cause of preventable vision loss in people between 20 and 65 years of age. Sodium glucose transporter 2 (SGLT2) inhibitors have been shown to reduce the risk for cardiovascular and renal events, however literature highlighting their potential role to prevent DR is limited. We therefore used a relevant mouse model (Akimba) to explore the effects of the SGLT2 inhibitor, Empagliflozin (EMPA), on the development of diabetic retinal changes. Here we show that when given in the early stages of type 1 diabetes (T1D), EMPA reduced the weight loss usually associated with T1D, decreased diabetes-associated polydipsia, lowered fasting blood glucose levels, decreased kidney-to-body weight ratios and, most importantly in the current context, substantially reduced retinal abnormalities associated with DR. We show that EMPA reduces vascular leakage indicated by lower albumin staining in the vitreous humor and diminishes expression of the pathogenic factor VEGF in the retina. Additionally, EMPA significantly alters the retinal genetic signature. Our findings suggest that SGLT2 inhibition may be a useful therapeutic approach to prevent the development of DR and its severity if given early in the disease process.

Sodium Glucose Cotransporter-2 Inhibitor Protects Against Diabetic Neuropathy and Nephropathy in Modestly Controlled Type 2 Diabetes: Follow-Up Study

AIMS

This three-year follow-up study aimed to elucidate whether sodium-glucose cotransporter-2 inhibitors (SGLT2is) have any protection against diabetic neuropathy and nephropathy in patients with type 2 diabetes via reducing variability in glycemia and extraglycemic factors or their averages.

METHODS

Two type 2 diabetic cohorts of 40 and 73 patients treated with or without SGLT2i along with 60 control subjects were recruited. Two diabetic cohorts matched for HbA1c levels and oral hypoglycemic agents other than SGLT2is underwent glycemic control with or without SGLT2is more than two years. The urinary albumin to creatinine ratio (ACR), estimated glomerular filtration rate (eGFR) every 3 months and neuropathy outcome measures and mean Z-score of 8 neurophysiological tests were determined at the baseline and endpoint. Glycemic variability, evaluated by the coefficient of variation of monthly measured HbA1c levels and casual postprandial plasma glucose (CPPG), and coefficient of variation and average of extraglycemic parameters in diabetic cohorts were determined.

RESULTS

The glycemic variability and variability of some extraglycemic factors in SGLT2i cohort were smaller than those in non-SGLT2i cohort. However, only smaller coefficient of variation of HbA1c improved some neuropathy outcome measures, and ameliorated eGFR decline. SGLT2i improved the Z-score of neurophysiological tests. The optimized changes in the blood pressure, HDL-cholesterol and uric acid by SGLT2i led to neurological and renal protection. SGLT2i decreased the prevalence of nephropathy significantly and the prevalence of neuropathy insignificantly.

CONCLUSION

Over 3 years period, SGLT2i significantly improved some neuropathy outcome measures, mean Z-score of 8 neurophysiological tests, and attenuated nephropathy in modestly controlled type 2 diabetes by reducing glycemic variability and mean nonglycemic factors of diabetic microvascular complication.

Relationship Between SGLT-2i and Ocular Diseases in Patients With Type 2 Diabetes Mellitus: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

This meta-analysis was conducted to explore the association between sodium-glucose cotransporter 2 inhibitors (SGLT-2is) and ocular diseases in type 2 diabetes mellitus (T2DM) patients.

METHODS

PubMed, Cochrane Central Registry of Controlled Trials, Web of Science and Springer were searched for articles on randomized controlled trials (RCTs) involving T2DM patients treated with SGLT-2i versus placebo or other hypoglycemic agents published prior to August 2021. The primary outcome of this meta-analysis was incidence of ocular diseases, which was assessed using risk ratios (RR) and 95% confidence intervals (CI). We reviewed 47 papers and compared the effect of SGLT-2i with the effect of the control groups (placebo and other hypoglycemic drugs) on the incidence of ocular diseases.

RESULTS

Compared with controls, overall SGLT-2i use in T2DM patients was not associated with incidences of cataract, glaucoma, retinal disease and vitreous disease. Ertugliflozin (RR=0.47, P=0.01) reduced the risk for retinal disease, while empagliflozin (RR=0.44, P=0.05) reduced the risk for diabetic retinopathy (DR) compared with controls. SGLT-2i (RR=0.50, P=0.02), perhaps empagliflozin (RR=0.47, P=0.06), reduced the risk of retinal disease compared with active hypoglycemic agents. Canagliflozin (RR=4.50, P=0.03) increased the risk for vitreous disease compared with placebo.

CONCLUSIONS

There was no significant correlation between overall SGLT-2i and ocular diseases (cataract, glaucoma, retinal disease, vitreous disease, corneal disease, conjunctival disease, uveal disease, eye haemorrhage and vision problems) in T2DM patients. Ertugliflozin and empagliflozin may protect against ocular diseases, but canagliflozin may promote ocular diseases.

Decreased expression of Glucagon-like peptide-1 receptor and Sodium-glucose co-transporter 2 in patients with proliferative diabetic retinopathy

PURPOSE

To investigate the expression of Glucagon-like peptide-1 receptor (GLP-1R), sodium-glucose co-transporter (SGLT) 1, SGLT2, Glucose transporter type 1 (GLUT1) and GLUT2 in patients with diabetic retinopathy (DR).

METHODS

We obtained peripheral blood mononuclear cells (PBMCs) and vitreous samples from 26 proliferative DR (PDR) patients, 25 non-proliferative DR (NPDR) patients, 25 non-DR (NDR) patients, and 26 nondiabetic patients with idiopathic epiretinal membranes (ERMs, control). The protein level and mRNA expression level of GLP-1R were quantified by immunoblot and qRT-PCR and the levels of SGLT1, SGLT2, GLUT1, and GLUT2 expression were determined by PCR. Their association with clinical parameters and PBMCs/vitreous cytokine was analyzed. Furthermore, immunofluorescence staining of GLP-1R and SGLT2 was carried out on samples of fibrovascular membranes (FVMs) retrieved from 26 patients with PDR and 26 patients with ERMs.

RESULTS

The transcriptional levels of GLP-1R and SGLT2 in PBMCs were significantly more decreased in PDR patients than in patients without DR and controls, which was simultaneously associated with an increased level of expression of tumor necrosis factor (TNF)-α and interferon (IFN)-γ. The expression levels of GLUT1 and GLUT2 were tightly correlated with their SGLT partners, respectively. Further, Immunofluorescence staining showed no positive staining of GLP-1R and SGLT2 was detected in the FVMs from PDR.

CONCLUSIONS

GLP-1R and SGLT2 were significantly decreased in PDR patients which was associated with an increased level of expression of TNF-α and IFN-γ. These findings implicate that defective GLP-1R and SGLT2 signaling may potentially correlate with immune response cytokines in patients with PDR.

Effect of exenatide on peripheral nerve excitability in type 2 diabetes

OBJECTIVE

To assess the effect of exenatide (a GLP-1 receptor agonist), dipeptidyl peptidase-IV (DPP-IV) inhibitors, and sodium-glucose co-transporter 2 (SGLT-2) inhibitors on measures of peripheral nerve excitability in patients with type 2 diabetes.

METHODS

Patients receiving either exenatide (n = 32), a DPP-IV inhibitor (n = 31), or a SGLT-2 inhibitor (n = 27) underwent motor nerve excitability assessments. Groups were similar in age, sex, HbA_1c, diabetes duration, lipids, and neuropathy severity. An additional 10 subjects were assessed prospectively over 3 months while oral anti-hyperglycaemic therapy was kept constant. A cohort of healthy controls (n = 32) were recruited for comparison.

RESULTS

Patients receiving a DPP-IV or SGLT-2 inhibitor demonstrated abnormalities in peak threshold reduction, S2 accommodation, superexcitability, and subexcitability. In contrast, patients treated with exenatide were observed to have normal nerve excitability. In the prospective arm, exenatide therapy was associated with an improvement in nerve function as patients demonstrated corrections in S2 accommodation, superexcitability, and subexcitability at follow-up. These changes were independent of the reductions in HbA_1c following exenatide treatment.

CONCLUSIONS

Exenatide was associated with an improvement in measures of nerve excitability in patients with type 2 diabetes.

SIGNIFICANCE

Exenatide may improve peripheral nerve function in type 2 diabetes.

Sodium-glucose co-transporter 2 inhibitors and diabetic retinopathy: insights into preservation of sight and looking beyond

Sodium-glucose co-transporter 2 Inhibitors (SGLT2i) were initially developed as therapeutic options for patients with type 2 diabetes mellitus (T2DM). Recently, randomized clinical trials have investigated their effects in cardiorenal protection through major adverse cardiovascular event reduction and reductions in diabetic nephropathy. While multiple mechanisms are proposed for this protection, microvascular protection is the primary component of their efficacy. While not primarily emphasized in clinical trials, evidence in other studies suggests that SGLT2i may confer retinoprotective effects via some of the same mechanisms in the aforementioned cardiorenal trials. Diabetic patients are susceptible to vision loss with chronic hyperglycemia promoting inflammation, edema, and retinal pathological changes. Targeting these pathways via SGLT2i may represent opportunities for providers to decrease retinopathy in high-risk T2DM patients, reduce disease progression, and lower drug burden in diabetic retinopathy patients. Further comprehensive clinical trials investigating these associations are needed to establish the potential retinoprotective effects of SGLT2i.

Diabetes and Its Complications: Therapies Available, Anticipated and Aspired

Worldwide, diabetes ranks among the ten leading causes of mortality. Prevalence of diabetes is growing rapidly in low and middle income countries. It is a progressive disease leading to serious co-morbidities, which results in increased cost of treatment and over-all health system of the country. Pathophysiological alterations in Type 2 Diabetes (T2D) progressed from a simple disturbance in the functioning of the pancreas to triumvirate to ominous octet to egregious eleven to dirty dozen model. Due to complex interplay of multiple hormones in T2D, there may be multifaceted approach in its management. The 'long-term secondary complications' in uncontrolled diabetes may affect almost every organ of the body, and finally may lead to multi-organ dysfunction. Available therapies are inconsistent in maintaining long term glycemic control and their long term use may be associated with adverse effects. There is need for newer drugs, not only for glycemic control but also for prevention or mitigation of secondary microvascular and macrovascular complications. Increased knowledge of the pathophysiology of diabetes has contributed to the development of novel treatments. Several new agents like Glucagon Like Peptide - 1 (GLP-1) agonists, Dipeptidyl Peptidase IV (DPP-4) inhibitors, amylin analogues, Sodium-Glucose transport -2 (SGLT- 2) inhibitors and dual Peroxisome Proliferator-Activated Receptor (PPAR) agonists are available or will be available soon, thus extending the range of therapy for T2D, thereby preventing its long term complications. The article discusses the pathophysiology of diabetes along with its comorbidities, with a focus on existing and novel upcoming antidiabetic drugs which are under investigation. It also dives deep to deliberate upon the novel therapies that are in various stages of development. Adding new options with new mechanisms of action to the treatment armamentarium of diabetes may eventually help improve outcomes and reduce its economic burden.

The Role of SGLT2 Inhibitor on the Treatment of Diabetic Retinopathy

Diabetic retinopathy (DR) is one of the most serious complications of diabetic microangiopathy. DR has an early onset and is not easy to detect. When visual impairment occurs, the optimal period for therapy is often missed. Therefore, the prevention and treatment of DR should start from the early stage of diabetes. Sodium-dependent glucose transporter 2 inhibitor (SGLT2i) is a new antidiabetic drug which is mainly used in clinical practice to control blood glucose of patients with type 2 diabetes prone to develop chronic heart failure. Recent studies have found that SGLT2 is also expressed in the human retina. Now, the prevention and treatment of diabetic retinopathy with SGLT2i while reducing blood sugar has become a new research field. Hence, this article reviewed the recent therapeutic and research progress of SGLT2 in the treatment of diabetic retinopathy.

SGLT2 Inhibitors, GLP-1 Agonists, and DPP-4 Inhibitors in Diabetes and Microvascular Complications: A Review

The prevalence of diabetes and its associated complications is increasing throughout the decades. Promising diabetes medications were introduced to the market including GLP-1 agonists, DPP-4 inhibitors, and SGLT2 inhibitors aiming to target these complications. The literature lacks sufficient data regarding these new medications and their influence on nephropathy, retinopathy, and neuropathy. This review expands on the major results of effects of the 3 drug classes on microvascular complications. In our review, both SGLT2 inhibitors and GLP-1 agonists appear to have promising nephroprotective outcomes at this stage, with less promising outcomes seen with DPP-4 inhibitors. Moreover, the retinoprotective outcomes of both SGLT2 inhibitors and DPP-4 inhibitors were only tested on mice, while those of GLP-1 agonists were assessed in few trials. In addition, the results of both GLP-1 agonists and DPP-4 inhibitors showed discrepancies in these studies. On the contrary, conclusions regarding the effect of these medications on neuroprotective outcomes cannot be drawn at the time due to the lack of clinical trials targeting these complications. Hence, a clearer picture of the microvascular outcomes will manifest over time with the release of multiple upcoming clinical trials.

Effects of sodium-glucose cotransporter-2 inhibitors and dipeptidyl peptidase-4 inhibitors on diabetic retinopathy and its progression: A real-world Korean study

The sodium-glucose cotransporter-2 inhibitors (SGLT2is) reduce the incidence of macrovascular complications of diabetes, while their effect on diabetic retinopathy has not been clarified. We compared the effects of SGLT2is with those of dipeptidyl peptidase-4 inhibitors (DPP4is) on the risk of diabetic retinopathy and its progression in people with type 2 diabetes. We performed a retrospective cohort study among people with type 2 diabetes who started on a SGLT2i or DPP4i from 2014 to 2016 according to the Korean National Health Insurance Service database. Subjects initiated on a SGLT2i or DPP4i were matched on a 1:1 basis according to their propensity scores, and Cox proportional hazards regression models were used to calculate the hazard ratios for the risk of diabetic retinopathy and its progression. After propensity score-matching, 41,430 patients without a history of diabetic retinopathy were identified as new users of a SGLT2i (n = 20,175) or DPP4i (n = 20,175). The hazard ratio (95% CI) for diabetic retinopathy was 0.89 (0.83–0.97) for SGLT2i initiators compared with DPP4i initiators. In patients with a history of diabetic retinopathy (n = 4,663 pairs), there was no significant difference in diabetic retinopathy progression between SGLT2i initiators and DPP4i initiators (hazard ratio 0.94, 95% CI 0.78–1.13). This real-world cohort study showed that SGLT2is might be associated with lower risk of diabetic retinopathy compared with DPP4is. Randomized controlled trials are needed to investigate the long-term effect of SGLT2is in diabetic retinopathy in people with diabetes.

Acute and Direct Effects of Sodium-Glucose Cotransporter 2 Inhibition on Glomerular Filtration Rate in Spontaneously Diabetic Torii Fatty Rats

Recent clinical studies indicate that sodium-glucose cotransporter 2 (SGLT2) inhibitors exhibit a renoprotective effect. While studies at the single nephron level suggest that direct effects of SGLT2 inhibitors on renal hemodynamics may be a possible mechanism underlying their renoprotective effect, few studies have focused on such direct effects at the whole-kidney level. In the present study, we investigated the acute and direct effect of SGLT2 inhibition on creatinine clearance, an index of whole-kidney glomerular filtration rate (GFR), in a rat model of type 2 diabetes. Twelve to fifteen-week-old male Spontaneously Diabetic Torii (SDT) fatty rats and Sprague-Dawley rats were used as diabetic animals and non-diabetic controls, respectively. Under general anesthesia, baseline urine samples were collected from the left and right ureters for 1 h. The selective SGLT2 inhibitor ipragliflozin or vehicle was subsequently administered intravenously and post-drug urine was collected for 1 h. Baseline and post-drug blood samples were collected immediately before baseline urine collection and immediately after post-drug urine collection, respectively. Plasma glucose, urine volume, urinary glucose and albumin excretion were measured, and creatinine clearance was calculated. Blood pressure and heart rate were monitored continuously throughout the experiment. A single intravenous injection of ipragliflozin increased both urine output and glucose excretion, but reduced creatinine clearance without affecting systemic blood pressure. These results suggest that SGLT2 inhibition directly reduced whole-kidney GFR, most likely due to a reduction in intraglomerular pressure, by altering local renal hemodynamics, which may contribute to the renoprotective effects demonstrated in clinical studies.

Exosomes derived from platelet-rich plasma mediate hyperglycemia-induced retinal endothelial injury via targeting the TLR4 signaling pathway

In this study, we aimed to investigate whether exosomes derived from platelet-rich plasma (PRP-Exos) can regulate hyperglycemia-induced retinal injury via targeting the TLR4 signaling pathway. We studied the effects of PRP-Exos on retinal endothelial injury in diabetic rats and human retinal endothelial cells (HRECs) in vitro. Isolated PRP-Exos were observed by transmission electron microscopy and flow cytometry. Samples were obtained from the retinas of rats and cultured HRECs after treatment to analyze reactive oxygen species levels. Immunofluorescence and Western blotting were conducted to assess the levels of adhesion molecules and the TLR4 signaling pathway. The content of CXCL10 in PRP-Exos was analyzed by Western blot. The plasma level of PRP-Exos was greatly increased in diabetic rats. In cultured HRECs, PRP-Exos induced the production of malonyldialdehyde(MDA) and reactive oxygen species(ROS) and inhibited the activity of superoxide dismutase(SOD). Further analysis showed that the activation of the TLR4 pathway by PRP-Exos played a pivotal role in regulating inflammation. The inhibition of the TLR4 pathway by TAK-242 had a robust protective effect on PRP-Exo-induced retinal endothelial injury in vitro and vivo. In addition, PRP-Exo-derived CXCL10 led to retinal endothelial injury, and antagonizing CXCL10 with a CXCL10-neutralizing antibody dramatically attenuated such injury. In summary, PRP-Exos mediate hyperglycemia-induced retinal endothelial injury by upregulating the TLR4 signaling pathway.

Efficacy and safety of ipragliflozin as add-on to metformin for type 2 diabetes: a meta-analysis of double-blind randomized controlled trials

Objectives: To evaluate the efficacy and safety of ipragliflozin as add-on therapy to metformin in patients with type 2 diabetes mellitus.Methods: Systematic literature searches were performed in several databases across PubMed, the Cochrane Central Register of Controlled Trials, Embase, Medline, ClinicalTrials.gov, PsycINFO, and Web of Science from inception to 12 March 2019. After the extraction of data from eligible studies, randomized controlled trials (RCTs) were assessed for quality and analyzed statistically. Standardized mean difference (SMD) and risk ratio (RR) with 95% CIs were used to evaluate efficacy and safety end-points. Sensitivity analyses and subgroup analyses based on intervention times were also performed.Results: Five RCTs with 847 patients were included. Compared to metformin alone, ipragliflozin as an adjuvant to metformin reduced glycated hemoglobin (HbA1c) in 12 weeks and 24 weeks, respectively [12 w: SMD -0.30, 95% CI -0.51 to -0.10%, p = 0.004; 24 w: SMD -0.88, 95% CI -1.04 to -0.72%, p < 0.00001; Total: SMD -0.66, 95% CI -0.79 to -0.53%, p < 0.00001]. In addition, ipragliflozin as adjuvant therapy to metformin body weight (Total: SMD -1.47, 95% CI [-1.80,-1.14], p < 0.00001), waist circumference (Total: SMD -1.09, 95% CI [-1.62,-0.56], p < 0.00001), and blood pressure (SBP Total: SMD -3.36, 95% CI [-5.11.-1.61], p = 0.0002; DBP Total: SMD -2.18, 95% CI [-3.63,-0.74], p = 0.003). Compared to metformin alone, ipragliflozin as an adjuvant to metformin showed significant risks in the skin and subcutaneous tissue disorders and constipation.Conclusion: Compared to metformin alone, ipragliflozin plus metformin significantly improved glycemic control, reduced body weight, and lowered blood pressure; however, further high-quality trials are required to determine their long-term efficacy and safety.

New anti-hyperglycaemic agents for type 2 diabetes and their effects on diabetic retinopathy

There has been an increase in the range of non-insulin anti-hyperglycaemic agents used to treat type 2 diabetes. With the globally rising rates of type 2 diabetes and complications such as diabetic retinopathy, it is important for ophthalmologists to be aware of these new agents and their impacts on diabetic retinopathy and diabetic macular oedema. We conducted a review of the literature to determine if there were any beneficial or harmful effects of the currently used anti-hyperglycaemic agents on diabetic retinopathy or diabetic macular oedema. Our review of the current literature found that apart from thiazolidinediones, anti-hyperglycaemic agents have been reported to have beneficial or neutral effects on diabetic eye complications. Thiazolidinediones (pioglitazone is the only one currently available) have been linked to incident or worsening diabetic macular oedema, although the rate is believed to be low. Glucagon-like peptide 1 (GLP1) agonists (incretins) in general are beneficial except semaglutide which is associated with increased rates of diabetic retinopathy complications. These results have implications for selection of anti-hyperglycaemic agents for patients with diabetic retinopathy or macular oedema. Further studies need to be conducted to identify if reported beneficial effects are independent of the impact of glycaemic control. Early worsening of retinopathy with tight glycaemic control should also be noted in interpretation of future studies.

Effect of ipragliflozin, an SGLT2 inhibitor, on cardiac histopathological changes in a non-diabetic rat model of cardiomyopathy

AIMS

We investigated the effect of the selective sodium-dependent glucose cotransporter 2 (SGLT2) inhibitor ipragliflozin on cardiac dysfunction and histopathology in a non-diabetic rat model of cardiomyopathy.

MAIN METHODS

Ipragliflozin was mixed with chow (0.01%, w/w) and administered to male DahlS.Z-Lepr^fa/Lepr^fa (DS/obese) rats for 8 weeks. Male DahlS.Z-Lepr⁺/Lepr⁺ (DS/lean) rats of the same age were used as controls. Systolic blood pressure (SBP) and heart rate (HR) were measured every 4 weeks. After 8 weeks of treatment, echocardiography and histopathological examinations were performed. Further, the effect of ipragliflozin on blood and urine parameters were investigated.

KEY FINDINGS

In the DS/obese rats, ipragliflozin delayed the age-related increase in SBP without affecting HR, reduced left ventricular (LV) mass and intraventricular septal thickness in echocardiography, and ameliorated hypertrophy of cardiomyocytes and LV fibrosis in histopathological examination. Although ipragliflozin significantly increased both urine volume and urinary glucose excretion in DS/obese rats, it did not alter plasma glucose levels.

SIGNIFICANCE

Ipragliflozin prevented LV hypertrophy and fibrosis in non-diabetic DS/obese rats without affecting plasma glucose levels. These findings suggest that SGLT2 inhibitors have a cardio-protective effect in non-diabetic patients with cardiomyopathy.

Pathological Features of Diabetic Retinopathy in Spontaneously Diabetic Torii Fatty Rats

OBJECTIVE

The Spontaneously Diabetic Torii (SDT) fatty rat, established by introducing the fa allele (obesity gene) of the Zucker fatty rat into the SDT rat genome, is a new model of obese type 2 diabetes. We studied the pathologic features of diabetic retinopathy (DR) in this animal.

METHODS

The eyes of SDT fatty, SDT (controls), and Sprague Dawley (SD) rats (normal controls) were enucleated at 8, 16, 24, 32, and 40 weeks of age (n = 5-6 for each rat type at each age). The retinal thicknesses, numbers of retinal folds, and choroidal thicknesses were evaluated. Immunostaining for glial fibrillary acidic protein (GFAP) and vascular endothelial growth factor (VEGF) was performed. Quantitative analyses of the immunopositive regions were performed using a cell-counting algorithm.

RESULTS

The retinas tended to be thicker in the SDT fatty rats and SDT rats than in the SD rats; the choroids tended to be thicker in the SDT fatty rats than in the SD rats. The retinal folds in the SDT fatty rats developed earlier and were more severe than in the SDT rats. Quantitative analyses showed that the GFAP- and VEGF-positive regions in the retinas of the SDT fatty rats were significantly larger than those of the SDT rats.

CONCLUSIONS

SDT fatty rats developed more severe DR earlier than the SDT rats. The SDT fatty rats might be useful as a type 2 diabetes animal model to study DR.

First-dose effect of the SGLT2 inhibitor ipragliflozin on cardiovascular activity in spontaneously diabetic Torii fatty rats

The first dose of a sodium-dependent glucose cotransporter 2 (SGLT2) inhibitor induces osmotic diuresis and can thereby affect cardiovascular activity in hyperglycemic patients. We aimed to determine whether the first dose of the selective SGLT2 inhibitor ipragliflozin affects cardiovascular activity in non-diabetic Sprague-Dawley (SD) rats and Spontaneously Diabetic Torii (SDT) fatty rats in two studies, a urine collection study and a telemetry study. In the former study, urine was collected for 24 hours after a single oral dose of ipragliflozin. In the latter study, systolic blood pressure (SBP) and heart rate (HR) were continuously monitored for 24 hours under conscious and unrestrained conditions from immediately before the administration of ipragliflozin. The telemetry study was conducted in a crossover design at successive 1 week intervals. Cardiovascular autonomic nerve activity was calculated from the SBP and HR. SDT fatty rats exhibited polyuria, glucosuria and hyperglycemia. In addition, the mean and standard deviation of SBP were higher, while the coefficient of variance of HR was lower than the respective parameters in SD rats. Ipragliflozin increased both urine output and urinary glucose excretion, and the increases were more pronounced in SDT fatty rats than in SD rats. In contrast, ipragliflozin had no effect on SBP, the standard deviation of SBP, HR, and the coefficient of variance of HR, or on autonomic nerve activity in either rat strain. These results suggest that the first dose of the SGLT2 inhibitor ipragliflozin has little impact on cardiovascular activity despite causing glucosuria with osmotic diuresis.

Protective Effect of Ipragliflozin on Pancreatic Islet Cells in Obese Type 2 Diabetic db/db Mice

Ipragliflozin is a selective sodium glucose cotransporter 2 (SGLT2) inhibitor that increases urinary glucose excretion and subsequently improves hyperglycemia in patients with type 2 diabetes mellitus (T2DM). To assess the beneficial effect of ipragliflozin on the mass and function of pancreatic β-cells under diabetic conditions, obese T2DM db/db mice were treated with ipragliflozin for 5 weeks. Glucose and lipid metabolism parameters, pathological changes in pancreatic islet cells and insulin content were evaluated. Pathological examination of pancreatic islet cells comprised measuring the ratios of insulin- and glucagon-positive cells and levels of oxidative stress markers. Hemoglobin A1c, plasma glucose, non-esterified fatty acid and triglyceride levels in ipragliflozin-treated groups were reduced compared to the diabetic control (DM-control) group. Histopathological examination of pancreatic islet cells revealed strong insulin staining and reduced glucagon staining in the ipragliflozin 10 mg/kg-treated group compared with the DM-control group. The ratio of α- to β-cell mass was lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group and was similar to that of the non-diabetic control group. The density of immunostaining for 4-hydroxy-2-nonenal, an oxidative stress marker, in pancreatic islets was significantly lower in the ipragliflozin 10 mg/kg-treated group than the DM-control group. Pancreatic insulin content tended to be higher in the ipragliflozin-treated groups than the DM-control group. Our findings demonstrate the benefit of ipragliflozin treatment in improving glucolipotoxicity and reducing oxidative stress in pancreatic islet cells. Treatment with ipragliflozin may protect against the progressive loss of islet β-cells in patients with T2DM.

Effect of Empagliflozin, a Selective Sodium-Glucose Cotransporter 2 Inhibitor, on Kidney and Peripheral Nerves in Streptozotocin-Induced Diabetic Rats

The effect of sodium-glucose cotransporter 2 inhibitors on peripheral nerves and kidneys in diabetes mellitus (DM) remains unexplored. Therefore, this study aimed to explore the effect of empagliflozin in diabetic rats. DM in rats was induced by streptozotocin injection, and diabetic rats were treated with empagliflozin 3 or 10 mg/kg. Following 24-week treatment, response thresholds to four different stimuli were tested and found to be lower in diabetic rats than in normal rats. Empagliflozin significantly prevented hypersensitivity (P<0.05) and the loss of skin intraepidermal nerve fibers, and mesangial matrix expansion in diabetic rats. Results of this study demonstrate the potential therapeutic effects of empagliflozin for the treatment of diabetic peripheral neuropathy and nephropathy.

Tolerability and Efficacy of Ipragliflozin in The Management of Inadequately Controlled Type 2 Diabetes mellitus: A Systematic Review and Meta-analysis

AIM

Ipragliflozin is a new antidiabetic agent that works through enhancing renal glucose excretion. We aim to synthesize evidence from published randomized controlled trials (RCTs) on the safety and efficacy of ipragliflozin in the management of type 2 diabetes mellitus (T2DM).

METHODS

We searched PubMed, Scopus, Web of Science, and Cochrane Central register of clinical trials using relevant keywords. Records were screened for eligible studies and data were extracted and synthesized using Review Manager Version 5.3 for windows. Subgroup and sensitivity analyses were conducted.

RESULTS

We included 13 RCTs (N=2535 patients) in the final analysis. The overall effect estimates favoured ipragliflozin 50mg monotherapy group over placebo in terms of: HbA1c (Standardized mean difference (SMD)=-1.20%, 95% Confidence interval (95% CI)=[-1.47, -0.93]; p<0.001), fasting plasma glucose (SMD=-1.30 mg/dL, 95% CI [-1.93, -0.67]; p<0.001), fasting serum insulin (SMD=-1.64 μU/mL, 95% CI [-2.70, -0.59]; p=0.002), and body weight (SMD=-0.85 kg, 95% CI [-1.19, -0.51]; p<0.001). Similarly, better glycemic control and significant body weight reduction compared to placebo were attained in ipragliflozin 50 mg combination with metformin, insulin with/without dipeptidyl peptidase-4 inhibitor, sulfonylurea, and pioglitazone. Ipragliflozin, either alone or in combination, exhibits acceptable safety profile.

CONCLUSION

The presented meta-analysis provides class one evidence that ipragliflozin is safe and effective in the management of T2DM either as monotherapy or an add-on.

Comparisons of diabetic retinopathy events associated with glucose-lowering drugs in patients with type 2 diabetes mellitus: A network meta-analysis

AIM

To assess the comparative effects of glucose-lowering drugs (GLDs) on the risk of diabetic retinopathy (DR) in patients with type 2 diabetes mellitus (T2DM).

METHODS

We systematically searched Cochrane Central Register of Controlled Trials, PUBMED and EMBASE from inception to January 17, 2017 to identify randomized controlled trials (RCTs) that reported DR events among T2DM patients receiving any GLD. Random-effects pairwise and network meta-analyses were performed to calculate odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

A total of 37 independent RCTs with 1806 DR events among 100 928 patients with T2DM were included. The mean duration of diabetes was 8.7 years and mean baseline HbA1c was 8.2% (SD, 0.5%). Our network meta-analysis found that DPP-4i (OR, 1.20; 95% CI, 0.87-1.65), GLP-1RA (OR, 1.19; 95% CI, 0.94-1.52) and SGLT2 inhibitors (OR, 0.79; 95% CI, 0.49-1.28) were not associated with a higher risk of DR than placebo; however, a significantly increased risk of DR was associated with DPP-4i in the pairwise meta-analysis (OR, 1.27; 95% CI, 1.05-1.53). Sulfonylureas, on the other hand, were associated with a significantly increased risk of DR compared to placebo (OR, 1.67; 95% CI, 1.01-2.76).

CONCLUSIONS

Current evidence indicates that the association between DPP-4i, GLP-1RA or SGLT2 inhibitors and risk of DR remains uncertain in patients with T2DM. Some evidence suggests that sulfonylureas may be associated with increased risk of DR. However, given that DR events were not systematically assessed, these effects should be explored further in large-scale, well-designed studies.

Focusing on Sodium Glucose Cotransporter-2 and the Sympathetic Nervous System: Potential Impact in Diabetic Retinopathy

The prevalence of diabetes is at pandemic levels in today's society. Microvascular complications in organs including the eye are commonly observed in human diabetic subjects. Diabetic retinopathy (DR) is a prominent microvascular complication observed in many diabetics and is particularly debilitating as it may result in impaired or complete vision loss. In addition, DR is extremely costly for the patient and financially impacts the economy as a range of drug-related therapies and laser treatment may be essential. Prevention of microvascular complications is the major treatment goal of current therapeutic approaches; however, these therapies appear insufficient. Presently, sodium glucose cotransporter-2 (SGLT2) inhibitors may offer a novel therapy beyond simple glucose lowering. Excitingly, the EMPA-REG clinical trial, which focuses on the clinically used SGLT2 inhibitor empagliflozin, has been extremely fruitful and has highlighted beneficial cardiovascular and renal outcomes. The effects of SGLT2 inhibitors on DR are currently a topic of much research as outlined in the current review, but future studies are urgently needed to fully gain mechanistic insights. Here, we summarize current evidence and identify gaps that need to be addressed.

Effects of empagliflozin on the urinary albumin-to-creatinine ratio in patients with type 2 diabetes and established cardiovascular disease: an exploratory analysis from the EMPA-REG OUTCOME randomised, placebo-controlled trial

BACKGROUND

In a pooled analysis of short-term trials, short-term treatment with the sodium-glucose co-transporter-2 (SGLT2) inhibitor empagliflozin reduced albuminuria in patients with type 2 diabetes and prevalent albuminuria. In this exploratory analysis of the EMPA-REG OUTCOME trial, we report the short-term and long-term effects of empagliflozin on albuminuria in patients with type 2 diabetes and established cardiovascular disease, according to patients' baseline albuminuria status.

METHODS

In this randomised, double-blind, placebo-controlled trial at 590 sites in 42 countries, we randomly assigned patients aged 18 years and older with type 2 diabetes and established cardiovascular disease (1:1:1) to empagliflozin 10 mg, empagliflozin 25 mg, or placebo in addition to standard of care until at least 691 patients experienced an adjudicated event included in the primary outcome. We did the randomisation with a computer-generated random-sequence and interactive voice-response and web-response system, stratified by HbA_1c, BMI, region, and estimated glomerular filtration rate. Patients, investigators, and individuals involved in analysis of trial data were masked to treatment assignment. The primary and secondary efficacy and safety endpoints of this trial have been reported previously. Here, we report urinary albumin-to-creatinine ratio (UACR) data for the pooled empagliflozin group versus placebo according to albuminuria status at baseline (normoalbuminuria: UACR <30 mg/g; microalbuminuria: UACR ≥30 to ≤300 mg/g; and macroalbuminuria: UACR >300 mg/g). We did the analysis with mixed-model repeated measures including prespecified and post-hoc tests. This study is completed and registered with ClinicalTrials.gov, number NCT01131676.

FINDINGS

Between Sept 1, 2010, and April 22, 2013, we randomly assigned 7028 patients to treatment groups and 7020 patients received treatment. At baseline, we had UACR data for 6953 patients: 4171 (59% of treated patients; 1382 assigned to placebo and 2789 assigned to empagliflozin) had normoalbuminuria, 2013 (29%; 675 assigned to placebo and 1338 assigned to empagliflozin) had microalbuminuria, and 769 (11%; 260 assigned to placebo and 509 assigned to empagliflozin) had macroalbuminuria. Median treatment duration was 2·6 years (IQR 2·0-3·4; 136 weeks) and median observation time was 3·1 years (2·2-3·6; 164 weeks). After short-term treatment at week 12, the placebo-adjusted geometric mean ratio of UACR change from baseline with empagliflozin was -7% (95% CI -12 to -2; p=0·013) in patients with normoalbuminuria, -25% (-31 to -19; p<0·0001) in patients with microalbuminuria, and -32% (-41 to -23; p<0·0001) in patients with macroalbuminuria. The reductions in UACR were maintained with empagliflozin in all three groups compared with placebo during long-term treatment when measured at 164 weeks. At follow-up, after cessation of treatment for a median of 34 or 35 days, UACR was lower in the empagliflozin versus placebo group in those with baseline microalbuminuria (placebo-corrected adjusted geometric mean ratio of relative change from baseline with empagliflozin: -22%, 95% CI -32 to -11; p=0·0003) or macroalbuminuria (-29%, -44 to -10; p=0·0048), but not for patients with baseline normoalbuminuria (1%, -8 to 10; p=0·8911). Patients treated with empagliflozin were more likely to experience a sustained improvement from microalbuminuria to normoalbuminuria (hazard ratio [HR] 1·43, 95% CI 1·22 to 1·67; p<0·0001) or from macroalbuminuria to microalbuminuria or normoalbuminuria (HR 1·82, 1·40 to 2·37; p<0·0001), and less likely to experience a sustained deterioration from normoalbuminuria to microalbuminuria or macroalbuminuria (HR 0·84, 0·74 to 0·95; p=0·0077). The proportions of patients with any adverse events, serious adverse events, and adverse events leading to discontinuation increased with worsening UACR status at baseline, but were similar between treatment groups. The proportion of patients with genital infections was greater with empagliflozin than placebo in all subgroups by UACR status.

INTERPRETATION

These results support short-term and long-term benefits of empagliflozin on urinary albumin excretion, irrespective of patients' albuminuria status at baseline.

FUNDING

Boehringer Ingelheim & Eli Lilly and Company Diabetes Alliance.

The roles of sodium-glucose cotransporter 2 inhibitors in preventing kidney injury in diabetes

Diabetic nephropathy (DN) is the leading cause of end stage renal disease (ESRD) worldwide. The early effective treatment of high plasma glucose could delay or prevent the onset of DN. Sodium-glucose cotransporter 2 (SGLT2) inhibitors are new target treatments for ameliorating high plasma glucose and help to maintain glucose homeostasis in diabetic patients. Reduced renal glucose reabsorption by SGLT2 inhibition seems to have high potential to improve glycemic control in diabetes mellitus (DM) not only through glucose lowering but also through glucose-independent effects such as blood pressure-lowering and direct renal effects in diabetes. Of note, the important events in the pathogenesis of glucose-induced renal injury and DN including oxidative stress, inflammation, fibrosis and apoptosis conditions have shown to be ameliorate after the treatment with SGLT2 inhibitors. Interestingly, SGLT2 inhibitors have been reported to reduce albuminuria in DM via an activation of renal tubuloglomerular feedback by increased macula densa sodium and chloride delivery, leading to afferent vasoconstriction and attenuated diabetes-induced renal hyperfiltration. These effects also help to conserve glomerular integrity. Thus, the treatment of diabetes mellitus using SGLT2 inhibitors could be one of the effective approach for the management of diabetic-associated kidney disease like DN. This review summarizes the up to date information and discusses the bidirectional relationship between the SGLT2 inhibitor treatments and the renal functions that are available from both basic research and clinical reports. The details of renal outcomes of SGLT2 inhibitors in DN are also provide in this review.

Effect of Dapagliflozin Treatment on Fluid and Electrolyte Balance in Diabetic Rats

AIM

This study evaluates the effect of dapagliflozin, a SGLT2 inhibitor, on fluid or electrolyte balance and its effect on urea transporter-A1 (UT-A1), aquaporin-2 (AQP2) and Na-K-2Cl cotransporter (NKCC2) protein abundance in diabetic rats.

METHODS

Diabetes mellitus (DM) was induced by injection of streptozotocin into the tail vein. Serum Na+, K+, Cl- concentration, urine Na+, K+, Cl- excretion, blood glucose, urine glucose excretion, urine volume, urine osmolality and urine urea excretion were analyzed after the administration of dapagliflozin. UT-A1, AQP2 and NKCC2 proteins were detected by western blot.

RESULTS

Dapagliflozin treatment decreased blood glucose concentration by 38% at day 7 and by 47% at day 14 and increased the urinary glucose excretion rate compared with the untreated diabetic animals. Increased 24-hour urine volume, decreased urine osmolality and hyponatremia, hypokalemia and hypochloremia observed in diabetic rats were attenuated by dapagliflozin treatment. Western blot analysis showed that UT-A1, AQP2 and NKCC2 proteins are upregulated in DM rats over control rats; dapagliflozin treatment results in a further increase in inner medulla tip UT-A1 protein abundance by 42% at day 7 and by 46% at day 14, but it did not affect the DM-induced upregulation of AQP2 and NKCC2 proteins.

CONCLUSION

Dapagliflozin treatment augmented the compensatory changes in medullary transport proteins in DM. These changes would tend to conserve solute and water even with persistent glycosuria. Therefore, diabetic rats treated with dapagliflozin have a mild osmotic diuresis compared to nondiabetic animals, but this does not result in an electrolyte disorder or significant volume depletion.

Functional imaging of pharmacological action of SGLT2 inhibitor ipragliflozin via PET imaging using 11C-MDG

Sodium‐dependent glucose cotransporter 2 (SGLT2) is a pharmacological target of type 2 diabetes mellitus. The aim of this study was to noninvasively visualize the pharmacological action of a selective SGLT2 inhibitor ipragliflozin in the kidney using positron emission tomography (PET) imaging with ¹¹C‐methyl‐d‐glucoside (¹¹C‐MDG), an SGLT‐specific radio‐labeled substrate. PET imaging with ¹¹C‐MDG in vehicle‐treated rats demonstrated that intravenously injected ¹¹C‐MDG substantially accumulated in the renal cortex, reflecting that the compound was reabsorbed by SGLTs. In contrast, ipragliflozin‐treated rats showed significantly lower uptake of ¹¹C‐MDG in renal cortex in a dose‐related manner, suggesting that ipragliflozin inhibited the renal reabsorption of ¹¹C‐MDG. This method of visualizing the mode of action of an SGLT2 inhibitor in vivo has demonstrated the drug's mechanism in reducing renal glucose reabsorption in kidney in living animals.