Dapagliflozin ameliorated retinal vascular permeability in diabetic retinopathy rats by suppressing inflammatory factors.

BACKGROUND: Diabetic retinopathy is a common microvascular complication of diabetes and one of the major causes of blindness in the working-age population. Emerging evidence has elucidated that inflammation drives the key mechanism of diabetes-mediated retinal disturbance. As a new therapeutic drug targeting diabetes, whether dapagliflozin could improve vascular permeability from the perspective of anti-inflammatory effect need to be further explored. METHODS: Type 2 diabetic retinopathy rat model was established and confirmed by fundus fluorescein angiography (FFA). ELISA detected level of plasma inflammatory factors and C-peptide. HE staining, immunohistochemistry and western blot detected histopathology changes of retina, expression of retinal inflammatory factors and tight junction proteins. RESULTS: Dapagliflozin exhibited hypoglycemic effect comparable to insulin, but did not affect body weight. By inhibiting expression of inflammatory factors (NLRP3, Caspase-1, IL-18, NF-κB) in diabetic retina and plasma, dapagliflozin reduced damage of retinal tight junction proteins and improved retinal vascular permeability. The anti-inflammatory effect of dapagliflozin was superior to insulin. CONCLUSIONS: Dapagliflozin improved retinal vascular permeability by reducing diabetic retinal and plasma inflammatory factors. The anti-inflammatory mechanism of dapagliflozin is independent of hypoglycemic effect and superior to insulin.

Association between area under the C-peptide curve during an oral glucose tolerance test and diabetic retinopathy in type 2 diabetes patients.

AIMS/INTRODUCTION: To evaluate the relative contributions of the area under the C-peptide curve (AUCC ) in diabetic retinopathy (DR) during an oral glucose tolerance test and C-peptide release test in patients with type 2 diabetes. MATERIALS AND METHODS: We retrospectively analyzed the data of 969 patients. Their general characteristics were retrieved. A series of parameters for assessing pancreatic ß-cells function, such as the AUCC for six time periods: 0-60 min (AUCC0-60 ), 0-120 min (AUCC0-120 ), 0-180 min (AUCC0-180 ), 60-120 min (AUCC60-120 ), 60-180 min (AUCC60-180 ) and 120-180 min (AUCC120-180 ); the area under the glucose-time curve for six time periods: 0-60 min (AUCG0-60 ), 0-120 min (AUCG0-120 ), 0-180 min (AUCG0-180 ), 60-120 min (AUCG60-120 ), 60-180 min (AUCG60-180 ) and 120-180 min (AUCG120-180 ) and their related indexes, were calculated through 0-180 min oral glucose tolerance test and C-peptide release test. We used univariate analysis to examine the potential factors affecting DR. Spearman's correlation was used to analyze the correlation between AUCC -related indexes and DR. The logistic regression model was used to investigate AUCC and its related indexes' contribution to incidence DR. A smooth curve fitting model was used to determine the correlation, non-linear relationship, and threshold effect between AUCC and DR. RESULTS: Of the 969 patients with type 2 diabetes, 469 (48.40%) and 500 (51.60%) were classified as the DR group and non-DR group. Compared with the non-DR group, the DR patients had lower AUCC and AUCC /AUCG . Spearman's correlation analysis showed that AUCC -related indexes were all negatively correlated with DR. The logistic regression analysis determined that there were associations between AUCC and DR in the adjusted models. The odds ratio values of AUCC0-60 , AUCC0-120 , AUCC0-180 , AUCC0-60 /AUCG0-60 , AUCC0-120 /AUCG0-120 , AUCC0-180 /AUCG0-180 , AUCC60-120 , AUCC60-180 , AUCC120-180 , AUCC60-120 /AUCG60-120 , AUCC60-180 /AUCG60-180 and AUCC120-180 /AUCG120-180 were 0.817 (0.750, 0.890), 0.925 (0.895, 0.955), 0.951 (0.932, 0.970), 0.143 (0.060, 0.340), 0.194 (0.093, 0.406), 0.223 (0.116, 0.427), 0.886 (0.842, 0.933), 0.939 (0.915, 0.963), 0.887 (0.846, 0.930), 0.253 (0.133, 0.479), 0.282 (0.160, 0.497) and 0.355 (0.220, 0.573), respectively. AUCC showed a non-linear relationship with DR, with an inflection point. The inflection points of AUCC180 /AUCG180 , AUCC60-120 , AUCC60-180 , AUCC120-180 , AUCC60-120 /AUCG60-120 , AUCC60-180 /AUCG60-180 , AUCC120-180 /AUCG120-180 and DR were 17.51, 0.542, 6.6, 15.7, 8.23, 0.534, 0.593 and 0.808 (P < 0.0001). When the indexes related to the AUCC were less than the inflection point value, they were significantly negatively associated with DR. CONCLUSIONS: The indexes related to the AUCC for six time periods during an oral glucose tolerance test and C-peptide release test was closely associated with the incidence to DR in patients with type 2 diabetes. AUCC has the added advantage of being a cheap and convenient risk assessment over traditional ophthalmic screening.

Sex Differences in the Association Between AST/ALT and Incidence of Type 2 Diabetes in Japanese Patients with Nonalcoholic Fatty Liver Disease: A Retrospective Cohort Study.

OBJECTIVES/INTRODUCTION: The purpose of the current study was to investigate the association between Aspartate Transaminase (AST)/Alanine transaminase(ALT) and type 2 diabetes (T2DM) in nonalcoholic fatty liver disease (NAFLD) patients and to determine whether there were sex differences. METHODS: In the retrospective study, we collected data on NAFLD patients (1, 896 men and 465 women) at Murakami Memorial Hospital from 2004 to 2015. Data were stratified by sex to investigate the association between AST/ALT and T2DM incidence by sex. Multiple regression analysis, smooth curve fitting model and subgroup analysis were used to determine the correlation, non-linear relationship and threshold effect between AST/ALT and T2DM. RESULTS: In our study, 157 men and 40 women developed T2DM at follow-up. After adjusting for risk factors, AST/ALT was significantly associated with T2DM in men with NAFLD but not in women with NAFLD. The risk of T2DM increased as the AST/ALT ratio decreased. Besides, in male NAFLD patients, AST/ALT showed a non-linear relationship with T2DM, with an inflection point value of 0.964. When the AST to ALT ratio was below the threshold (AST/ALT <0.964), AST/ALT was significantly negatively associated with T2DM (HR = 0.177, 95% CI 0.055-0.568; P = 0.0036). In contrast, when AST/ALT >0.964, no significant association was found (HR = 3.174, 95% CI 0.345-29.167; P = 0.3074). Moreover, subgroup analysis showed that GGT could alter the relationship between AST/ALT and T2DM. In the group with GGT ≤ 40, AST/ALT was strongly associated with T2DM (HR = 0.24, 95% CI 0.09-0.66; P = 0.0059). CONCLUSIONS: These results suggested that there were sex differences in the association between AST/ALT and T2DM in NAFLD participants. A non-linear association between AST/ALT and T2DM was observed in males. AST/ALT in the normal GGT group (GGT ≤40) might better facilitate the early screening of T2DM.

Effects of mulberry twig alkaloids(Sangzhi alkaloids) and metformin on blood glucose fluctuations in combination with premixed insulin-treated patients with type 2 diabetes.

Introduction: We aimed to evaluated the effect of premixed insulin (Ins), premixed insulin combined with metformin (Ins+Met) or mulberry twig alkaloids(Ins+SZ-A) on blood glucose fluctuations in patients with type 2 diabetes (T2DM) using continuous glucose monitors (CGM). Methods: Thirty patients with T2DM and poor blood glucose control using drugs were evaluated for eligibility during the screening period. Subsequently, their original hypoglycemic drugs were discontinued during the lead-in period, and after receiving Ins intensive treatment for 2 weeks, they were randomly assigned to receive either Ins, Ins+Met, or Ins+SZ-A treatment for the following 12 weeks. The main efficacy endpoint comprised changes in their CGM indicators changes (mean blood glucose level [MBG], standard deviation of blood glucose [SDBG], mean amplitude of glycemic excursions [MAGE], postprandial glucose excursions [PPGE], the largest amplitude of glycemic excursions [LAGE], mean of daily difference [MODD], time in range between 3.9-10.0 mmol/L [TIR] and area under the curve for each meal [AUCpp]) during the screening, lead-in, and after 12-week treatment period. Changes in glycosylated hemoglobin (HbA1c), fasting blood glucose (FBG), 1-h postprandial blood glucose (1h-PBG), 2-h postprandial blood glucose (2h-PBG), fasting blood lipids and postprandial blood lipids were also measured at baseline and after 12 weeks of treatment. Results: The CGM indicators of the three groups during the lead-in period all showed significant improvements compared to the screening period (P<0.05). Compared with those in the lead-in period, all of the CGM indicators improved in the the Ins+Met and Ins+SZ-A groups after 12 weeks of treatment (P<0.05), except for MODD. After 12-week treatment, compared with the Ins group, Ins+Met and Ins+SZ-A groups showed improved MBG, SDBG, TIR, breakfast AUCpp,lunch AUCpp, HbA1c, FBG, 1h-PBG, fasting blood lipid and postprandial blood lipid indicators (P<0.05). Further, the LAGE, PPGE, MAGE, dinner AUCpp and 2h-PBG levels of the Ins+SZ-A group were significantly lower than those of the Ins+Met and Ins groups (P<0.05). Conclusion: Our findings highlight the efficacy of combination therapy (Ins+SZ-A or Ins+Met) in improving blood glucose fluctuations, as well as blood glucose and lipid levels. Ins+SZ-A reduces postprandial blood glucose fluctuations more than Ins+Met and Ins groups. Trial registration number: ISRCTN20835488.

Liraglutide intervention improves high-glucose-induced reactive gliosis of Müller cells and ECM dysregulation.

Reactive gliosis of Müller cells plays an important role in the pathogenesis of diabetic retinopathy (DR). Liraglutide, a glucagon-like peptide-1 receptor (GLP-1R) agonist, has been shown to improve DR by inhibiting reactive gliosis. However, the mechanism of inhibition has yet to be elucidated. This study investigated the effects of liraglutide on Müller glia reactivity in the early stages of DR and the underlying mechanisms. Proteomics combined with bioinformatics analysis, HE staining, and immunofluorescence staining revealed ganglion cell loss, reactive gliosis of Müller cells, and extracellular matrix (ECM) imbalance in rats with early stages of DR. High glucose (HG) exposure up-regulated GFAP and TNF-α expression and down-regulated ITGB1 expression and FN1 content in extracellular fluid in rMC1 cells, thereby promoting reactive gliosis. GLP-1R knockdown and HG+DAPT inhibition experiments show that liraglutide balances ECM levels by inhibiting activation of the Notch1/Hes1 pathway and ameliorates high-glucose-induced Müller glia reactivity. Thus, the study provides new targets and ideas for improvement of DR in early stages.

Association between high-density lipoprotein cholesterol to apolipoprotein A ratio and diabetic retinopathy: A cross-sectional study.

AIMS: Our study is aimed to investigate the relationship between high-density lipoprotein cholesterol to apolipoprotein A ratio (HDL-C/ApoA) and diabetic retinopathy (DR) in subjects with type 2 diabetes mellitus (T2DM). METHODS: We retrospect the consecutive medical files of 1058 subjects with T2DM and recorded their clinical information and laboratory findings. Subjects with T2DM were divided into DR group (n = 522) and non-DR group (n = 536). We compared the lipids values of the two groups. Meanwhile we also observed the prevalence of DR at different HDL-C/ApoA levels. Binary logistic regression was used to correct confounding factors. Smooth curve fitting model and subgroup analysis were used to determine the correlation, non-linear relationship and threshold effect between HDL/ApoA and DR. RESULTS: HDL-C/ApoA value of DR group was significantly higher than non-DR group (0.88 ± 0.17 vs 0.84 ± 0.13, P < 0.05). The prevalence of DR significantly increased as HDL-C/ApoA level increased. There was association between HDL/ApoA levels and DR in the adjusted models (OR 1.55, 95%CI 0.60 to 4.02). After full adjustments for other relevant clinical covariates, patients with HDL/ApoA values in quartile 3 (Q3) had 1.50 times (95 % CI 1.00 to 2.17) and in Q4 had 2.39 times (95%CI 1.65 to 3.47) as high as the risk of DR compared with patients in Q1. HDL/ApoA showed a non-linear relationship with DR, with an inflection point value of 0.759. When HDL/ApoA>0.759, HDL/ApoA was significantly positively associated with DR (HR = 26.508, 95 % CI 7.623-92.174; P < 0.0001). Compared to patients with age < 60, HDL/ApoA was obviously associated with DR when age ≥ 60 (OR = 38.05, 95 % CI 8.06-179.69; P < 0.001). CONCLUSIONS: HDL-C/ApoA was found to be associated with the incidence of DR in patients with T2DM. After adjusting potential related factors HDL-C/ApoA OR value was 1.55 (95%CI 0.60 to 4.02). A non-linear association between HDL/ApoA and DR was observed in T2DM. Subgroup analysis showed that age could alter the relationship between HDL/ApoA and DR.

Autophagy Modulates the Migration of Retinal Pericytes Induced by Advanced Glycation End Products.

Retinal pericyte migration occurs in the early stage of diabetic retinopathy (DR), which is one of the important causes of pericyte loss. Autophagy has been found to play essential roles in the regulation of many types of cell migration. In this study, we explored the relationship between autophagy and retinal pericyte migration. In diabetic rats, the retinas became thinner, and the level of autophagy in each cell layer increased. In the primary culture of bovine retinal pericytes, we found that advanced glycation end products (AGEs) increased the migratory cell ability without influencing cell viability, which also increased the phosphorylation of focal adhesion kinase (FAK) and the expression of matrix metalloproteinase (MMP)-2 and decreased the expression of vinculin. AGEs-induced retinal pericyte autophagy and the inhibition of autophagy with chloroquine significantly inhibited cell migration, reversed AGEs-induced FAK phosphorylation, and changed vinculin and MMP-2 protein expression. These results provide a new insight into the migration mechanism of retinal pericytes. The early control of autophagy has a potential effect on regulating pericyte migration, which may contribute to keeping the integrity of retinal vessels in DR.

Bicyclol Regulates Hepatic Gluconeogenesis in Rats with Type 2 Diabetes and Non-alcoholic Fatty Liver Disease by Inhibiting Inflammation.

Hepatic gluconeogenesis plays an important role in maintaining the body's glucose metabolism homeostasis. Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver diseases, when combined with type 2 diabetes mellitus (T2DM), it can cause severe glucose metabolism disorders. Studies have confirmed that chronic liver inflammatory lesions are the basis of T2DM combined with NAFLD (T2DM-NAFLD), inhibiting liver inflammation can improve glucose metabolism disorders. It is essential to explore safe and effective drugs to inhibit liver inflammation to improve the body's glucose metabolism disorders. Bicyclol is a biphenyl derivative that has anti-oxidative and anti-inflammatory properties. In the present study, the hepatoprotective effects and underlying mechanisms of bicyclol in T2DM-NAFLD were investigated, and T2DM-NAFLD with/without bicyclol treatment models were established. The results revealed that bicyclol alleviated fasting blood glucose, serum transaminase levels, insulin resistance, hepatic adipogenesis, lipid accumulation and markedly reduced T2DM-NAFLD rat histological alterations of livers. Not only that, bicyclol markedly attenuated T2DM-NAFLD induced production of inflammation factors (IL-1ß and TNF-α). Moreover, bicyclol suppressed the expression of insulin/gluconeogenesis signaling pathway (Akt, PGC-1α and PEPCK). These findings suggested that bicyclol might be a potentially effective drug for the treatment of T2DM-NAFLD and other metabolic disorders.

Neuroprotective Role of GLP-1 Analog for Retinal Ganglion Cells via PINK1/Parkin-Mediated Mitophagy in Diabetic Retinopathy.

GLP-1 analogs have been widely used to treat patients with type 2 diabetes in recent years and studies have found that GLP-1 analogs have multiple organ benefits. However, the role of GLP-1 analogs in diabetic retinopathy (DR), a common complication of diabetes mellitus (DM), remains controversial. Retinal ganglion cells (RGCs) are the only afferent neurons responsible for transmitting visual information to the visual center and are vulnerable in the early stage of DR. Protection of RGC is vital for visual function. The incretin glucagon-like peptide-1 (GLP-1), which is secreted by L-cells after food ingestion, could lower blood glucose level through stimulating the release of insulin. In the present study, we evaluated the effects of GLP-1 analog on RGCs both in vitro and in vivo. We established diabetic rat models in vivo and applied an RGC-5 cell line in vitro. The results showed that in high glucose conditions, GLP-1 analog alleviated the damage of RGCs. In addition, GLP-1 analog prevented mitophagy through the PINK1/Parkin pathway. Here we demonstrated the neuroprotective effect of GLP-1 analog, which may be beneficial for retinal function, and we further elucidated a novel mechanism in GLP-1 analog-regulated protection of the retina. These findings may expand the multi-organ benefits of GLP-1 analogs and provide new insights for the prevention of DR.