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

Drug exposure as a predictor in diabetic retinopathy risk prediction models; a systematic review and meta-analysis

PURPOSE

To conduct a systematic review to assess drug exposure handling in diabetic retinopathy (DR) risk prediction models, a network-meta-analysis to identify drugs associated with DR and a meta-analysis to determine which drugs contributed to enhanced model performance.

DESIGN

Systematic review and meta-analysis.

METHODS

We included studies presenting DR models incorporating drug exposure as a predictor. We searched EMBASE, MEDLINE and SCOPUS from inception to December 2023. We evaluated the quality of studies using the Prediction model Risk of Bias Assessment Tool and certainty using GRADE. We conducted network meta-analysis and meta-analysis to estimate the odds ratio (OR) and pooled C-statistic, respectively, and 95% confidence intervals (CI) (PROSPERO: CRD42022349764).

RESULTS

Of 5,653 records identified, we included 28 studies of 678,837 type 1 or 2 diabetes participants, of which 38,579 (5.7%) had DR. A total of 19, 3 and 7 studies were at high, unclear, and low risk of bias, respectively. Drugs included in models as predictors were: insulin (n=24), antihypertensives (n=5), oral antidiabetics (n=12), lipid-lowering drugs (n=7), antiplatelets (n=2). Drug exposure was modelled primarily as a categorical variable (n=23 studies). Two studies handled drug exposure as time-varying covariates, and one as a time-dependent covariate. Insulin was associated with an increased risk of DR (OR= 2.50; 95%-CI: 1.61-3.86). Models that included insulin (n=9) had a higher pooled C-statistic (C-statistic=0.84, CI: 0.80-0.88), compared to models (n=9) that incorporated a combination of drugs alongside insulin (C-statistic= 0.79, CI:0.74-0.84), as well as models (n=3) not including insulin (C-statistic =0.70, CI: 0.64-0.75). Limitations include the high risk of bias and significant heterogeneity in reviewed studies.

CONCLUSION

This is the first review assessing drug exposure handling in DR prediction models. Drug exposure was primarily modelled as a categorical variable, with insulin associated with improved model performance. However, due to suboptimal drug handling, associations between other drugs and model performance may have been overlooked. This review proposes the following for future DR prediction models: 1) evaluation of drug exposure as a variable, 2) use of time-varying methodologies, and 3) consideration of drug regimen details. Improving drug exposure handling could potentially unveil novel variables capable of significantly enhancing the predictive capability of prediction models.

Incidence of diabetic retinopathy in anti-tnf treated rheumatic disease patients with type 2 diabetes

OBJECTIVE

This study aimed to evaluate the impact of anti-TNF (biological) therapies on the incidence and progression of diabetic retinopathy.

MATERIALS AND METHODS

A cross-sectional analysis of 50 diabetic patients with rheumatic diseases (group 1) was performed. An age-, sex-, and HbA1c-matched control group (group 2) was formed from a pool of diabetic patients who underwent regular eye examinations. The presence or absence of diabetic retinopathy was also assessed. Comorbidities such as hypertension, coronary artery disease, and hyperlipidemia were also evaluated as possible confounding factors.

RESULTS

Hundred eyes of 50 patients were evaluated in each group. Only three patients in group 1 had non-proliferative retinopathy. The median duration of rheumatic disease was 9 years, whereas that of diabetes was 11 years. The mean duration of anti-TNF therapy was 4 years. In the control group of diabetes-only patients, 13 patients developed some form of newly diagnosed diabetic retinopathy during the last five years. The calculated retinopathy occurrence between the groups was statistically significant (p < 0.05). In this study, the incidence rate ratio for patients receiving anti-TNF treatment was calculated as 0.4 in the study.

CONCLUSION

TNF inhibitors, with their anti-inflammatory effects, positively impact diabetic complications by reducing the incidence of retinopathy. To our knowledge, this is the first study to evaluate retinopathy development after anti-TNF therapy.

Diabetic retinopathy screening integrated in a multidisciplinary diabetes care clinic: a pilot project

OBJECTIVE

To characterize patients referred for diabetic retinopathy (DR) screening in a unique multidisciplinary diabetes care clinic at a tertiary care centre.

METHODS

A retrospective study was conducted involving patients who were referred to the Cardiac and Renal Endocrine Clinic at a tertiary care centre (University Health Network) for DR screening between April 2019-March 2020 and November 2020-August 2021. Patients' demographics; micro- and macrovascular disease measurements; visual acuity, intraocular pressure, fundus imaging, and optical coherence tomography results were collected and analyzed.

RESULTS

Of the 64 patients who attended the clinic, 21 patients (33%) with type 2 diabetes had on-site DR screening. The remaining 43 patients had DR screening within 6 months of the appointment or were under ophthalmology care with annual screening visits elsewhere. Of the 21 patients who underwent retinopathy screening, 7 patients (33%) had DR: 4 had mild nonproliferative DR, 2 had moderate nonproliferative DR, 1 had proliferative DR, and 1 had macular edema. Patients with DR had a significantly longer diabetes duration than patients without DR (24.5 ± 10.2 years vs 12.5 ± 5.8 years; p = 0.0247). No significant differences were observed in glycemic control, blood pressure, lipid profiles, kidney function, visual acuity, or intraocular pressure.

CONCLUSIONS

Our analysis suggests a potential benefit of integrated DR screening in patients with long-standing diabetes as part of a multidisciplinary diabetes care clinic to diagnose and manage DR. Future work is needed to further develop such clinics and investigate their long-term effect on patient outcomes.

Protective effect of alizarin on vascular endothelial dysfunction via inhibiting the type 2 diabetes-induced synthesis of THBS1 and activating the AMPK signaling pathway

BACKGROUND

In this study, we investigated the protective effects of alizarin (AZ) on endothelial dysfunction (ED). AZ has inhibition of the type 2 diabetes mellitus (T2DM)-induced synthesis of thrombospondin 1 (THBS1). Adenosine 5'-monophosphate- activated protein kinase (AMPK), particularly AMPKα2 isoform, plays a critical role in maintaining cardiac homeostasis.

PURPOSE

The aim of this study was to investigate the ameliorative effect of AZ on vascular injury caused by T2DM and to reveal the potential mechanism of AZ in high glucose (HG)-stimulated human umbilical vein endothelial cells (HUVECs) and diabetic model rats.

STUDY DESIGN

HUVECs, rats and AMPK-/- transgenic mice were used to investigate the mitigating effects of AZ on vascular endothelial dysfunction caused by T2DM and its in vitro and in vivo molecular mechanisms.

METHODS

In type 2 diabetes mellitus rats and HUVECs, the inhibitory effect of alizarin on THBS1 synthesis was verified by immunohistochemistry (IHC), immunofluorescence (IF) and Western blot (WB) so that increase endothelial nitric oxide synthase (eNOS) content in vitro and in vivo. In addition, we verified protein interactions with immunoprecipitation (IP). To probe the mechanism, we also performed AMPKα2 transfection. AMPK's pivotal role in AZ-mediated prevention against T2DM-induced vascular endothelial dysfunction was tested using AMPKα2-/- mice.

RESULTS

We first demonstrated that THBS1 and AMPK are targets of AZ. In T2DM, THBS1 was robustly induced by high glucose and inhibited by AZ. Furthermore, AZ activates the AMPK signaling pathway, and recoupled eNOS in stressed endothelial cells which plays a protective role in vascular endothelial dysfunction.

CONCLUSIONS

The main finding of this study is that AZ can play a role in different pathways of vascular injury due to T2DM. Mechanistically, alizarin inhibits the increase in THBS1 protein synthesis after high glucose induction and activates AMPKα2, which increases NO release from eNOS, which is essential in the prevention of vascular endothelial dysfunction caused by T2DM.

Impact of GLP-1 Agonists and SGLT-2 Inhibitors on Diabetic Retinopathy Progression: An Aggregated Electronic Health Record Data Study

PURPOSE

To examine the effects of glucagon-like peptide-1 receptor (GLP-1) agonists compared to SGLT-2 inhibitors on diabetic retinopathy.

DESIGN

Retrospective clinical cohort study using TriNetX, a federated electronic health records network comprising multiple healthcare organizations.

METHODS

Patients with an International Classification of Diseases, Tenth Revision (ICD-10) code of nonproliferative diabetic retinopathy (PDR) and monotherapy treatment, excluding insulin, with GLP-1 agonists or SGLT-2 inhibitors. Patients with a history of PDR prior to initiation of treatment were excluded. The rate of progression to PDR and rate of development of diabetic macular edema (DME) were compared between patients on GLP-1 agonists compared to those on SGLT-2 inhibitors. The groups were propensity score matched for age, gender, ethnicity, race, type of diabetes, and severity of PDR. Main outcomes included rate and relative risk (RR) of progression to PDR and risk of DME in the GLP-1 agonist group versus the SGLT-2 inhibitor group.

RESULTS

A total of 6481 patients were identified in the GLP-1 cohort and the SGLT-2 inhibitor cohort after propensity score matching. At 1 and 3 years after initiation of therapy, a higher rate of progression of PDR was noted (RR: 1.26, CI 1.04-1.51, P = .017 at 1 year, RR: 1.284, CI 1.1-1.499, P = .002 at 3 years) in the GLP-1 agonist cohort compared to the SGLT-2 inhibitor cohort. There was a higher rate of DME noted at 3 months (RR: 1.192, CI 1.059-1.276, P = .002), 6 months (RR: 1.22, CI 1.13-1.32, P < .001), 1 year (RR: 1.24, CI 1.15-1.33, P < .001), and at 3 years (RR: 1.29, CI 1.21-1.38, P < .001) in the GLP-1 agonist cohort compared to the SGLT-2 inhibitor cohort.

CONCLUSIONS

A higher rate of progression of PDR and risk of new-onset DME was observed in patients on monotherapy with GLP-1 agonists compared to those on SGLT-2 inhibitors. It is important for clinicians to be aware of these potential effects and to consider the current retinopathy status when initiating treatment with newer hypoglycemic agents to ensure these patients are appropriately monitored for developing potential vision-threatening complications.

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.

The effect evaluation of continuous nursing intervention in patients with type 2 diabetic retinopathy

INTRODUCTION

To evaluate the application effect of continuous nursing intervention in type 2 diabetic retinopathy (DR).

METHODS

Patients with type 2 DR were selected and divided into intervention group and control group by random. The control group received routine nursing intervention, and the intervention group received continuous nursing intervention on the basis of the control group. The clinical effects of the two groups were compared.

RESULTS

After 1 and 2 years of intervention, the intervention group compared to the control group. The rate of visual acuity decrease was significantly lower (p < 0.05). Fasting blood glucose, 2 h postprandial blood glucose, and glycosylated hemoglobin were significantly lower (p < 0.05). The self-management ability and satisfaction were significantly higher, and the readmission rate was significantly lower (p < 0.05).

CONCLUSION

The continuous nursing intervention model has a good clinical effect on the visual acuity of patients with type 2 DR.

Ocular and Plasma Pharmacokinetics of Enavogliflozin Ophthalmic Solution in Preclinical Species

An enavogliflozin ophthalmic solution (DWRX2008) is being developed to treat diabetic retinopathy and macular edema. This study evaluated the ocular distribution and plasma pharmacokinetics (PKs) of enavogliflozin in animal species. A sample of [14C] enavogliflozin was ocularly administered to two rabbits per time point at single doses of 600 μg/eye to evaluate ocular PK, which was evaluated using autoradiography until 48 h post-dose. Plasma concentrations after ocular administration in six rabbits, three rats, and three beagle dogs with single doses of 400 μg, 25 μg, and 100 μg, respectively, were investigated for 24 h. The retinal concentration of [14C] enavogliflozin reached Cmax at 2.0 h with an elimination half-life of 32.5 h, which remained above the IC50 value of sodium-dependent glucose transporter 2 until 24 h post-dose. In the plasma of rabbits, the fastest Tmax of 0.5 h and a 3.6 h half-life were observed among animal species. The relative bioavailability in rabbits after ocular administration was 3.4 compared to oral administration. Ocular administration of enavogliflozin could be a potential therapeutic route for diabetic retinal complications, based on relative bioavailability and effective delivery to the posterior ocular segment. DWRX2008 would be applicable to humans with favorable PK profiles and minimal systemic adverse effect.

Pharmacokinetic Comparison Between a Fixed-Dose Combination of Empagliflozin L-Proline/Metformin and Empagliflozin/Metformin in Healthy Korean Subjects

Empagliflozin and metformin are oral antidiabetic drugs commonly used to treat type 2 diabetes mellitus as a combination therapy. This study aimed to compare the pharmacokinetics and safety of a newly developed fixed-dose combination of 5-mg empagliflozin L-proline and 1000-mg metformin with the reference drug. A randomized, open-label, single-dose, 2-period, 2-treatment, crossover study was conducted in healthy Korean subjects. The subjects received a single oral dose of reference drug or test drug at each period. The pharmacokinetic (PK) parameters were calculated using a noncompartmental method. The geometric mean ratios and 90% confidence intervals of the plasma maximum concentration (Cmax ) and area under the concentration-time curve from time zero to the last quantifiable concentration (AUClast ) were calculated. A total of 27 healthy subjects were included in the PK analysis. For empagliflozin, the geometric mean ratios (90% confidence intervals) of the test to reference drug for Cmax and AUClast were 1.03 (0.99-1.08) and 1.03 (1.00-1.06), respectively. For metformin, the corresponding values for Cmax  and AUClast were 0.99 (0.92-1.06) and 1.00 (0.94-1.06), respectively. In conclusion, a fixed-dose combination of empagliflozin L-proline and metformin showed similar PK characteristics to the reference drug, and both drugs were safe in healthy subjects.

Incretins and microvascular complications of diabetes: neuropathy, nephropathy, retinopathy and microangiopathy

Glucagon-like peptide-1 receptor agonists (GLP-1RAs, incretin mimetics) and dipeptidyl peptidase-4 inhibitors (DPP-4is, incretin enhancers) are glucose-lowering therapies with proven cardiovascular safety, but their effect on microvascular disease is not fully understood. Both therapies increase GLP-1 receptor agonism, which is associated with attenuation of numerous pathological processes that may lead to microvascular benefits, including decreased reactive oxygen species (ROS) production, decreased inflammation and improved vascular function. DPP-4is also increase stromal cell-derived factor-1 (SDF-1), which is associated with neovascularisation and tissue repair. Rodent studies demonstrate several benefits of these agents in the prevention or reversal of nephropathy, retinopathy and neuropathy, but evidence from human populations is less clear. For nephropathy risk in human clinical trials, meta-analyses demonstrate that GLP-1RAs reduce the risk of a composite renal outcome (doubling of serum creatinine, eGFR reduction of 30%, end-stage renal disease or renal death), whereas the benefits of DPP-4is appear to be limited to reductions in the risk of albuminuria. The relationship between GLP-1RAs and retinopathy is less clear. Many large trials and meta-analyses show no effect, but an observed increase in the risk of retinopathy complications with semaglutide therapy (a GLP-1RA) in the SUSTAIN-6 trial warrants caution, particularly in individuals with baseline retinopathy. Similarly, DPP-4is are associated with increased retinopathy risk in both trials and meta-analysis. The association between GLP-1RAs and peripheral neuropathy is unclear due to little trial evidence. For DPP-4is, one trial and several observational studies show a reduced risk of peripheral neuropathy, with others reporting no effect. Evidence in other less-established microvascular outcomes, such as microvascular angina, cerebral small vessel disease, skeletal muscle microvascular disease and autonomic neuropathies (e.g. cardiac autonomic neuropathy, gastroparesis, erectile dysfunction), is sparse. In conclusion, GLP-1RAs are protective against nephropathy, whereas DPP-4is are protective against albuminuria and potentially peripheral neuropathy. Caution is advised with DPP-4is and semaglutide, particularly for patients with background retinopathy, due to increased risk of retinopathy. Well-designed trials powered for microvascular outcomes are needed to clarify associations of incretin therapies and microvascular diseases.

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.].

Proportion of people with diabetic retinopathy and macular oedema varies by ethnicity in a tertiary retinal clinic in Australia: findings from the Liverpool Eye and Diabetes Study (LEADS)

OBJECTIVE

There are limited data on the influence of ethnicity on diabetic retinopathy (DR). We sought to determine the distribution of DR by ethnic group in Australia.

DESIGN

Clinic-based cross-sectional study.

SETTING

Participants with diabetes in a defined geographical region of Sydney, Australia, who attended a tertiary retina referral clinic.

PARTICIPANTS

The study recruited 968 participants.

INTERVENTION

Participants underwent a medical interview and retinal photography and scanning.

PRIMARY OUTCOME MEASURES

DR was defined from two-field retinal photographs. Diabetic macular oedema (DMO) was defined from spectral domain optical coherence tomography (OCT-DMO). The main outcomes were any DR, proliferative DR (PDR), clinically significant macular oedema (CSME), OCT-DMO and sight-threatening DR (STDR).

RESULTS

There was high proportion of any DR (52.3%), PDR (6.3%), CSME (19.7%), OCT-DMO (28.9%) and STDR (31.5%) in people attending a tertiary retinal clinic. Participants of Oceanian ethnicity had the highest proportion of any DR and STDR (70.4% and 48.1%, respectively), while the lowest proportion was in participants of East Asian ethnicity (38.3% and 15.8%, respectively). Proportion of any DR and STDR in Europeans was 54.5% and 30.3%, respectively. Independent predictive factors for diabetic eye disease were ethnicity, longer duration of diabetes, higher glycated haemoglobin and higher blood pressure. Even after adjusting for risk factors, Oceanian ethnicity remained associated with twofold higher odds of any DR (adjusted OR 2.10, 95% CI 1.10 to 4.00) and all other forms of DR including STDR (adjusted OR 2.22, 95% CI 1.19 to 4.15).

CONCLUSION

In people attending a tertiary retinal clinic, the proportion of people with DR varies among ethnic groups. The high proportion in persons of Oceanian ethnicity suggests a need for targeted screening of this at-risk group. In addition to traditional risks factors, ethnicity may be an additional independent predictor of DR.

Diabetic Macular Oedema Guidelines: An Australian Perspective

The number of people living with diabetes is expected to rise to 578 million by 2030 and to 700 million by 2045, exacting a severe socioeconomic burden on healthcare systems around the globe. This is also reflected in the increasing numbers of people with ocular complications of diabetes (namely, diabetic macular oedema (DMO) and diabetic retinopathy (DR)). In one study examining the global prevalence of DR, 35% of people with diabetes had some form of DR, 7% had PDR, 7% had DMO, and 10% were affected by these vision-threatening stages. In many regions of the world (Australia included), DR is one of the top three leading causes of vision loss amongst working age adults (20-74 years). In the management of DMO, the landmark ETDRS study demonstrated that moderate visual loss, defined as doubling of the visual angle, can be reduced by 50% or more by focal/grid laser photocoagulation. However, over the last 20 years, antivascular endothelial growth factor (VEGF) and corticosteroid therapies have emerged as alternative options for the management of DMO and provided patients with choices that have higher chances of improving vision than laser alone. In Australia, since the 2008 NHMRC guidelines, there have been significant developments in both the treatment options and treatment schedules for DMO. This working group was therefore assembled to review and address the current management options available in Australia.

Outcomes and Complications of Pars Plana Vitrectomy for Tractional Retinal Detachment in People With Diabetes: A Systematic Review and Meta-analysis

Importance

Tractional retinal detachment (TRD) occurs in approximately 5% of people with proliferative diabetic retinopathy and poses a threat to vision. Pars plana vitrectomy (PPV) is the treatment of choice for TRD.

Objective

To determine anatomic and functional outcomes of PPV for the treatment of TRD in people with diabetes (dTRD).

Data Sources

MEDLINE and Embase were searched systematically from January 1, 2000, to February 20, 2022. In addition, a reference list of eligible studies were screened.

Study Selection

Eligible studies were those published in English, those reporting outcomes of PPV for dTRD, and those that included more than 25 eyes and with a minimum follow-up of 3 months.

Data Extraction and Synthesis

Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines for data extraction/synthesis were followed, and the National Institute for Health quality assessment tool was used to assess risk of bias. Study eligibility was determined independently by 2 reviewers; data extraction was conducted by 1 reviewer and entries checked for accuracy by another. Data were pooled using a random-effects model.

Main Outcomes and Measures

Main outcomes included rate of failure of retinal reattachment following 1 surgery and final visual acuity (VA). The association of baseline patient characteristics and surgical maneuvers with postoperative surgical outcomes was investigated.

Results

Of the 406 studies identified, 38 (3839 eyes) were eligible and included for analysis. Patients had a median (IQR) age of 52.2 (49.6-55.7) years. In the studies reporting patient sex (31 of 38 studies), 1441 were female individuals (50.1%). The overall failure rate of retinal reattachment after 1 surgery was 5.9% (95% CI, 1.4%-8.3%), and the mean final VA was 0.94 (95% CI, 0.82-1.05) logMAR (approximate Snellen equivalent, 6/53; 95% CI, 6/39-6/71). People with higher preoperative VA achieved higher postoperative vision (0.66 logMAR worse final vision; 95% CI, 0.39-0.84 per 1.0 logMAR worse at baseline; P <.001). On multivariable analysis, no other patient characteristics or surgical variables had a statistically significant association with outcomes.

Conclusions and Relevance

Results of this systematic review and meta-analysis suggest that PPV was an effective strategy to achieve retinal reattachment in people with dTRD. Given that higher preoperative VA was the only factor associated with higher postoperative vision, early intervention should be considered and discussed in detail with patients. Overall, final postoperative VA remains low, and patients should be counseled on the guarded prognosis of dTRD.

The concordance and discordance of diabetic kidney disease and retinopathy in patients with type 2 diabetes mellitus: A cross-sectional study of 26,809 patients from 5 primary hospitals in China

INTRODUCTION

Diabetic kidney disease (DKD) and diabetic retinopathy (DR) share similar pathophysiological mechanisms. However, signs of DKD may be present at diagnosis of diabetes without retinopathy. Risk factors for the development of DKD and DR may not be identical.

METHODS

This study aimed to evaluate the concordance and discordance between DKD and DR by investigating the distribution of DKD and DR in patients with type 2 diabetes mellitus from 5 Chinese cities. A total of 26,809 patients were involved in this study. The clinical characteristics were compared among patients based on the presence of DKD and DR. Logistic regression models were used to analyze the independent risk factors of DKD and DR.

RESULTS

The prevalence of DKD and DR was 32.3% and 34.6%, respectively. Among eligible patients, 1,752 patients without DR had an increased urinary albumin-to-creatinine ratio (ACR) or reduced estimated glomerular filtration rate (eGFR), and 1,483 patients with DR had no DKD. The positive predictive value of DR for DKD was 47.4% and negative predictive value was 67.1%. Elder age, male gender, a longer duration of disease, higher values of waist circumference and HbA1c were associated with both DR and DKD. A lower educational level was associated with DR. Higher BP and TG would predict increased prevalence of DKD.

CONCLUSIONS

DKD and DR shared many risk factors, but a significant discordance was present in patients with type 2 diabetes mellitus. DKD was more strongly associated with blood pressure and triglycerides than DR.

Changes and significance of retinal blood oxygen saturation and oxidative stress indexes in patients with diabetic retinopathy

BACKGROUND

Diabetic retinopathy (DR) is a diabetic complication that can severely affect the patients’ vision, eventually leading to blindness. DR is the most important manifestation of diabetic micro-vasculopathy and is mainly related to the course of diabetes and the degree of blood glucose control, while the age of diabetes onset, sex, and type of diabetes have little influence on it.

AIM

To explore the changes in blood oxygen saturation and oxidative stress indices of retinal vessels in patients with DR.

METHODS

In total, 94 patients (94 eyes) with DR (DR group) diagnosed at Jianyang people’s Hospital between March 2019 and June 2020, and 100 volunteers (100 eyes) (control group) without eye diseases, were included in this study. Arterial and venous blood oxygen saturation, retinal arteriovenous vessel diameter, and serum oxidative stress indicators in the two groups were compared. Based on the stage of the disease, the DR group was divided into the simple DR and proliferative DR groups for stratified analysis.

RESULTS

The oxygen saturation of the retinal vessels in the DR group was significantly higher than that in the control group (P < 0.05). The retinal vessel diameters between the DR and control groups were not significantly different. The serum malondialdehyde (MDA) and 8-hydroxydehydroguanosine (8-OHdG) levels in the DR group were significantly higher than those in the control group (P < 0.05). The serum superoxide dismutase (SOD) and reduced glutathione (GSH) levels in the DR group were significantly lower than those in the control group (P < 0.05). The oxygen saturation of the retinal vessels in the patients with proliferative DR was significantly higher than that in the patients with simple DR (P < 0.05). The retinal vessel diameter in patients with proliferative DR was not significantly different from that of patients with simple DR (P > 0.05). Serum MDA and 8-OHdG levels in patients with proliferative DR were significantly higher than those in patients with simple DR (P < 0.05). Serum SOD and GSH levels in patients with proliferative DR were significantly lower than those in patients with simple DR (P < 0.05).

CONCLUSION

Increased blood oxygen saturation of retinal arteries and veins and increased oxidative stress damage in patients with DR may be associated with decreased retinal capillary permeability and arterial oxygen dispersion, possibly reflecting the patient’s condition.

Trimetazidine mitigates high glucose-induced retinal endothelial dysfunction by inhibiting PI3K/Akt/mTOR pathway-mediated autophagy

Trimetazidine (TMZ), as a metabolic regulator, has been widely testified to exhibit positive therapeutic effects on various disease models, but its role in diabetic retinopathy has not been reported. Therefore, this study was designed with the purpose of exploring the effects of TMZ on high-glucose (HG)-induced retinal endothelial dysfunction and its underlying mechanism. To establish DR model in vitro, 30 mM glucose was applied to induce human retinal endothelial cells (HRECs). Cell proliferation, invasion, and migration were examined by means of Cell Counting Kit-8, transwell, and wound healing assays, respectively. The tubule formation experiment was used to test the tubulogenesis ability and fluorescein isothiocyanate (FITC)-albumin was utilized to measure the permeability of monolayer HRECs. In addition, immunofluorescence and Western blot were employed to detect protein expression. Compared with the HG-induced group, TMZ concentration dependently inhibited the proliferation, migration, and angiogenesis of HG-induced HRECs, decreased the permeability of monolayer HRECs, and increased the protein expression levels of Claudin-5 and VE-cadherin. In addition, TMZ intervention increased the expression of p-PI3K, p-AKT, and p-mTOR but decreased the expression of LC3I, LC3II, and Beclin 1, which were then partially reversed by P13 K inhibitor (LY294002). Moreover, the autophagy agonist rapamycin (RAPA) was also testified to reverse the inhibitory effects of TMZ on the proliferation, migration, and angiogenesis of HG-induced HRECs. In summary, TMZ inhibited excessive autophagy by activating PI3K/Akt/mTOR pathway, thereby improving retinal endothelial dysfunction induced by HG.

Relevance of Peptide Homeostasis in Metabolic Retinal Degenerative Disorders: Curative Potential in Genetically Modified Mice

The mammalian retina contains approximately 30 neuropeptides that are synthetized by different neuronal cell populations, glia, and the pigmented epithelium. The presence of these neuropeptides leaves a mark on normal retinal molecular processes and physiology, and they are also crucial in fighting various pathologies (e.g., diabetic retinopathy, ischemia, age-related pathologies, glaucoma) because of their protective abilities. Retinal pathologies of different origin (metabolic, genetic) are extensively investigated by genetically manipulated in vivo mouse models that help us gain a better understanding of the molecular background of these pathomechanisms. These models offer opportunities to manipulate gene expression in different cell types to help reveal their roles in the preservation of retinal health or identify malfunction during diseases. In order to assess the current status of transgenic technologies available, we have conducted a literature survey focused on retinal disorders of metabolic origin, zooming in on the role of retinal neuropeptides in diabetic retinopathy and ischemia. First, we identified those neuropeptides that are most relevant to retinal pathologies in humans and the two clinically most relevant models, mice and rats. Then we continued our analysis with metabolic disorders, examining neuropeptide-related pathways leading to systemic or cellular damage and rescue. Last but not least, we reviewed the available literature on genetically modified mouse strains to understand how the manipulation of a single element of any given pathway (e.g., signal molecules, receptors, intracellular signaling pathways) could lead either to the worsening of disease conditions or, more frequently, to substantial improvements in retinal health. Most attention was given to studies which reported successful intervention against specific disorders. For these experiments, a detailed evaluation will be given and the possible role of converging intracellular pathways will be discussed. Using these converging intracellular pathways, curative effects of peptides could potentially be utilized in fighting metabolic retinal disorders.

The Association Between Leucine and Diabetic Retinopathy in Different Genders: A Cross-Sectional Study in Chinese Patients With Type 2 Diabetes

OBJECTIVE

To explore the association between serum leucine (leu) and diabetic retinopathy (DR) in patients with type 2 diabetes (T2D) and then to analyze the influence of gender on the association.

METHOD

The electronic medical records of 1,149 T2D patients who met inclusion and exclusion criteria were retrieved from the Second Affiliated Hospital of Dalian Medical University and the First Affiliated Hospital of Jinzhou Medical University. Serum leu levels of all subjects were measured by liquid chromatography-mass spectrometry. Logistic regression was used to obtain the odds ratio (OR) and CI of leu-DR risk in multiple models. When using these models, restricted cubic spline (RCS) was used to test the potential non-linear relationship between multiple continuous independent variables, such as leu and DR (classification), and dependent variables. We also used the additive interaction method to evaluate the interaction effect between leu and gender on DR.

RESULTS

Leu was a protective factor of DR [0.78 (0.66, 0.92)]. When gender was divided into male and female, the above relationship was statistically significant only in men [0.73 (0.58, 0.94)]. Three indicators of additive interaction-RERI, AP, and S-suggested that there is no interaction between gender and leu on the risk of DR.

CONCLUSIONS

Male T2D patients with high leu levels may have a lower risk of DR.

Management of Hyperglycemia in Older Adults with Type 2 Diabetes

The increasing incidence of type 2 diabetes in the general population as well as enhanced life expectancy has resulted in a rapid rise in the prevalence of diabetes in the older population. Diabetes causes significant morbidity and impairs quality of life. Managing diabetes in older adults is a daunting task due to unique health and psychosocial challenges. Medical management is complicated by polypharmacy, cognitive impairment, urinary incontinence, injurious falls, and persistent pain. Health care providers now have several traditional and contemporary pharmacologic agents to manage diabetes. Avoidance of hypoglycemia is critical; however, evidence-based guidelines are lacking due to the paucity of clinical trials in older adults. For many in this population, maintaining independence is more important than adherence to published guidelines to prevent diabetes complications. The goal of diabetes care in older adults is to enhance the quality of life without subjecting these patients to intrusive and complicated interventions. Recent technological advancements such as continuous glucose monitoring systems can have crucial supplementary benefits in the geriatric population.

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.

Resveratrol inhibits neural apoptosis and regulates RAX/P-PKR expression in retina of diabetic rats

PURPOSE

This study was to investigate the effect of resveratrol (RSV) administration on diabetes-induced neural apoptosis and on RNA-dependent-protein-kinase (PKR)-associated protein X (RAX), PKR and phosphorylated PKR (P-PKR) expression and distribution in retina of diabetic rats.

METHODS

Retina was obtained from normal and diabetic Sprague-Dawley rats with or without RSV (5 and 10 mg/kg/d) treatment at 30-, 32-, 34- and 36-weeks. Apoptosis of retinal neural cells and distribution of RAX/P-PKR was assessed by TUNEL and immunofluorescence methods. Expression of RAX, PKR and P-PKR was evaluated by qRT-PCR and western-blotting methods.

RESULTS

Our study showed that the TUNEL-positive cells were mainly localized in ganglion cells layer (GCL), inner nuclear layer (INL) and outer nuclear layer (ONL) of the diabetic rat's retina at 30-, 32-, 34- and 36-weeks. RSV administration effectively suppressed the neural apoptosis in GCL, INL and ONL. Almost no TUNEL-positive cells were observed in retina of normal control and RSV-treated normal control rats. Our study also showed that the expression level of RAX, P-PKR in diabetic rats retina at 30-, 32-, 34-, and 36-weeks was elevated. With supplementation of 5 and 10 mg/kg/d RSV, the expression level of RAX and P-PKR was decreased (P < 0.05). The expression level of RAX and P-PKR in the retina of normal control rats was not altered by RSV. The expression level of PKR was not altered by streptozotocin injection and RSV treatment.

CONCLUSIONS

Our results suggested that RSV attenuates retinal neural apoptosis in diabetic rats retina may be via regulation RAX/P-PKR expression.

The role of peroxisome proliferator-activated receptors in healthy and diseased eyes

Peroxisome Proliferator-Activated Receptors (PPARs) are a family of nuclear receptors that play essential roles in modulating cell differentiation, inflammation, and metabolism. Three subtypes of PPARs are known: PPAR-alpha (PPARα), PPAR-gamma (PPARγ), and PPAR-beta/delta (PPARβ/δ). PPARα activation reduces lipid levels and regulates energy homeostasis, activation of PPARγ results in regulation of adipogenesis, and PPARβ/δ activation increases fatty acid metabolism and lipolysis. PPARs are linked to various diseases, including but not limited to diabetes, non-alcoholic fatty liver disease, glaucoma and atherosclerosis. In the past decade, numerous studies have assessed the functional properties of PPARs in the eye and key PPAR mechanisms have been discovered, particularly regarding the retina and cornea. PPARγ and PPARα are well established in their functions in ocular homeostasis regarding neuroprotection, neovascularization, and inflammation, whereas PPARβ/δ isoform function remains understudied. Naturally, studies on PPAR agonists and antagonists, associated with ocular pathology, have also gained traction with the development of PPAR synthetic ligands. Studies on PPARs has significantly influenced novel therapeutics for diabetic eye disease, ocular neuropathy, dry eye, and age-related macular degeneration (AMD). In this review, therapeutic potentials and implications will be highlighted, as well as reported adverse effects. Further investigations are necessary before any of the PPARs ligands can be utilized, in the clinics, to treat eye diseases. Future research on the prominent role of PPARs will help unravel the complex mechanisms involved in order to prevent and treat ocular diseases.

The effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus

OBJECTIVE

This study aimed to investigate the effects of chronic hypoxia on the endocrine-related parameters in elderly rats with type 2 diabetes mellitus.

METHODS

Sixty, 55-week-old, female SD rats were studied, among which 20 were randomly divided into a blank control group (the BCG), and 40 were intraperitoneally injected with low-dose streptozotocin (STZ) for modeling and divided into a model control group (the MCG, n=20) and a hypoxic group (the HG, n=20). The BCG and the MCG were fed routinely under normoxia, while the HG was fed in the hypoxic environment of an OxyCycler Model A84XO hypoxic chamber. After 12 weeks of intervention, the body weights, the fasting blood glucose (FBG) levels, the fasting insulin (FINS) levels, the blood lipid metabolism levels, the bone densities, the fresh weights of the femurs, the biomechanical properties of the femurs, the inflammatory factor levels, the H&E staining of the liver tissue, and the oil red O staining were compared.

RESULTS

The increases in weight gain and the FBG and FINS levels in the HG were lower than the corresponding levels in the MCG and were higher than the levels in the BCG (P<0.05). The TC, TG, and LDL-C levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05). The bone density and fresh weight of the femurs at 12 weeks after the intervention in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The maximum stress, maximum load, fracture load, and elastic modulus in the HG were higher than they were in the MCG and lower than they were in the BCG (P<0.05). The TNF-α, IL-6, PAI-1, and CRP levels in the HG were lower than they were in the MCG and higher than they were in the BCG (P<0.05).

CONCLUSION

Chronic hypoxia can improve the endocrine parameters and insulin resistance, improve the insulin sensitivity and the femoral biomechanics, reduce the inflammatory factors levels, and improve the glucose and lipid metabolism levels and liver function in elderly rats with type 2 diabetes.

Subpopulation Differences in the Cardiovascular Efficacy of Long-Acting Glucagon-Like Peptide 1 Receptor Agonists in Type 2 Diabetes Mellitus: A Systematic Review and Meta-analysis

INTRODUCTION

The cardiovascular efficacy of glucagon-like peptide 1 receptor agonists (GLP-1RAs) in type 2 diabetes mellitus (T2DM) are well documented; however, the differences in cardiovascular efficacy among subpopulations remain unknown. This systematic review and meta-analysis aimed to explore the differences in cardiovascular efficacy of long-acting GLP-1RAs among subpopulations of patients with T2DM and to assess the drug safety.

METHODS

Relevant studies up to March 31, 2020 were searched for in six electronic databases, namely PubMed, Cochrane Library, Embase, Clinical Trials, Science Direct, and Web of Science. The primary outcome was three-point major adverse cardiovascular events (including cardiovascular mortality, non-fatal myocardial infarction, and non-fatal stroke). Subpopulations were defined using ten selected influential factors, and the differences in cardiovascular efficacy in subpopulations stratified by different influential factors were accessed by synthesizing studies with random-effects models one by one.

RESULTS

A total of six cardiovascular outcome trials of long-acting GLP-1RAs, comprising 49,936 participants, were included. Among stratified subpopulations, no significant differences in the cardiovascular efficacy of long-acting GLP-1RAs were observed across the ten characteristics of subjects (all P for interaction > 0.05). Favorable trends were observed in the subpopulation with established cardiovascular disease (CVD) compared to that without (P = 0.171). With regards to safety, long-acting GLP-1RAs did not significantly increase the risk of retinopathy (OR 1.09; 95% CI 0.92-1.29; P = 0.316), but increase the risk of serious gastrointestinal events (OR 1.37; 95% CI 1.02-1.83; P = 0.037). Long-acting GLP-1RAs did not significantly increase the risk of serious adverse events (OR 0.92; 95% CI 0.85-1.00; P = 0.039).

CONCLUSIONS

Our analysis suggested no subpopulation differences in the cardiovascular efficacy of long-acting GLP-1RAs among stratified subpopulations, and favorable trends were only observed in the subpopulation with established CVD. These findings may have implications for the management of long-acting GLP-1RAs across subpopulations of patients with T2DM.

Sirtuin (Sirt) 3 Overexpression Prevents Retinopathy in Streptozotocin-Induced Diabetic Rats

BACKGROUND Sirtuin (Sirt) 3 could promote autophagy by downregulating the expression of genes related to neovascularization in retinal endothelial cells. In this study, we aimed to investigate the effect of Sirt3 overexpression on retinopathy in streptozotocin (STZ)-induced diabetic rats, and to assess its mechanisms. MATERIAL AND METHODS Ntraperitoneal injection of STZ in rats was used to produce a diabetic model. The study rats were divided into 4 groups (n=6 for each group): a control group; a model group; a model+scrambled adenovirus group; and a model+Sirt3 overexpression group. Hematoxylin and eosin (H&E) staining determined the pathological changes of retina tissues. Immunohistochemistry, fluorescence quantitative polymerase chain reaction, and western blotting were used to detect the expression of Sirt3, vascular endothelial growth factor (VEGF), and microtubule-associated protein 1A/1B-light chain 3 (LC3). RESULTS In the model group, the inner limiting membrane was swollen, uneven and thickened, and the capillary endothelial cells occasionally protruded into the inner limiting membrane. These abnormalities were prevented by Sirt3 overexpression. Compared with the control group, the expression of Sirt3 at both mRNA and protein levels in the model group was significantly reduced, while the expression of VEGF was increased versus the control group (P.