[Diabetic retinopathy risk factors]

Bone Marrow-Derived Mesenchymal Stem Cells Restored High-Fat-Fed Induced Hyperinsulinemia in Rats at Early Stage of Type 2 Diabetes Mellitus

Numerous studies have proposed the transplantation of mesenchymal stem cells (MSCs) in the treatment of typical type 2 diabetes mellitus (T2DM). We aimed to find a new strategy with MSC therapy at an early stage of T2DM to efficiently prevent the progressive deterioration of organic dysfunction. Using the high-fat-fed hyperinsulinemia rat model, we found that before the onset of typical T2DM, bone marrow-derived MSCs (BM-MSCs) significantly attenuated rising insulin with decline in glucose as well as restored lipometabolic disorder and liver dysfunction. BM-MSCs also favored the histological structure recovery and proliferative capacity of pancreatic islet cells. More importantly, BM-MSC administration successfully reversed the abnormal expression of insulin resistance-related proteins including GLUT4, phosphorylated insulin receptor substrate 1, and protein kinase Akt and proinflammatory cytokines IL-6 and TNFα in liver. These findings suggested that MSCs transplantation during hyperinsulinemia could prevent most potential risks of T2DM for patients.

Serum Iron and Risk of Diabetic Retinopathy

Background: Diabetic retinopathy (DR) is indicated as a major cause of blindness in the world. Emerging evidence supports the interaction of iron metabolism with diabetes. However, little research is available concerning the relationship between iron metabolism and DR. The intent of this paper is to describe the correlation between serum iron and the occurrence of DR. Methods: A total of 5321 participants who underwent related examinations as part of the National Health and Nutrition Examination Survey (2005–2008) were included. DR was defined by the criteria of the Early Treatment for Diabetic Retinopathy Study based on nonmydriatic fundus photography. The cutoff point of serum iron for DR was explored by the receiver operating characteristics curve. The relationship of serum iron with the occurrence of DR was explored by multivariate logistic regression models. Results: Participants with DR had significantly lower serum iron than the control group. Serum iron was negatively correlated with the occurrence of DR after the adjustment of pertinent variables (an odds ratio (OR) of 0.995 (95% CI: 0.992–0.999)). After dividing serum iron into quartiles, the third quartile was associated with DR with an OR of 0.601 (95% CI: 0.418–0.863). Furthermore, the cutoff point of serum iron had an inverse relationship for the occurrence of DR with an OR of 0.766 (95% CI: 0.597–0.984). Conclusion: Serum iron has an inverse association with the occurrence of DR in diabetic adults. The assessment of serum iron levels might be a part of follow-up visits with diabetic patients.

Methylenetetrahydrofolate reductase C677T polymorphism and diabetic retinopathy risk: a meta-analysis of the Chinese population

Objectives

This study evaluated associations between methylenetetrahydrofolate reductase (MTHFR ) C677T polymorphisms and diabetic retinopathy (DR) susceptibility within the Chinese population.

Methods

Five databases (PubMed, EMBASE, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure) were used for literature searches of open access articles from inception through April 2017.

Results

Eight publications were identified involving 600 DR cases, 363 healthy controls, and 646 nondiabetic retinopathy (NDR) controls. There was a positive association between MTHFR C677T polymorphisms and DR risk within the Chinese population (DR with NDR controls: T vs. C, odds ratio (OR): 2.14, 95% confidence interval (CI): 1.55–2.97; TT vs. CC, OR: 4.19, 95% CI: 2.09–8.41; TT + CT vs. CC, OR: 2.83, 95% CI: 1.86–4.40; TT vs. CC + CT, OR: 2.48, 95% CI: 1.52–4.05. DR with healthy controls: T vs. C, OR: 2.48, 95% CI: 1.99–3.09; TT vs. CC, OR: 4.92, 95% CI: 3.18–7.62; TT + CT vs. CC, OR: 3.22, 95% CI: 2.32–4.48; TT vs. CC + CT, OR: 3.11, 95% CI: 1.83–5.28). The association was similar in South China and North China, when stratifying by geographic areas.

Conclusion

MTHFR C677T polymorphisms increase DR risk within the Chinese population.

Mesenchymal stem cell therapy in type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM), which is characterized by the combination of relative insulin deficiency and insulin resistance, cannot be reversed with existing therapeutic strategies. Transplantation of insulin-producing cells (IPCs) was once thought to be the most promising strategy for treating diabetes, but the pace from the laboratory to clinical application has been obstructed due to its drawbacks. Mesenchymal stem cells (MSCs) harbor differentiation potential, immunosuppressive properties, and anti-inflammatory effects, and they are considered an ideal candidate cell type for treatment of DM. MSC-related research has demonstrated exciting therapeutic effects in glycemic control both in vivo and in vitro, and these results now have been translated into clinical practice. However, some critical potential problems have emerged from current clinical trials. Multi-center, large-scale, double-blind, and placebo-controlled studies with strict supervision are required before MSC transplantation can become a routine therapeutic approach for T2DM. We briefly review the molecular mechanism of MSC treatment for T2DM as well as the merits and drawbacks identified in current clinical trials.

Risk factors for diabetic retinopathy: a case-control study

BACKGROUND

Diabetic retinopathy (DR) is the major cause of blindness among working age adults. The aim of the study was to investigate risk factors for development of DR.

METHODS

A case-control study was performed based on data from 240 individuals (80 cases and 160 controls) attending the Outpatient Specialty Clinic of the University of South Santa Catarina (UNISUL), between Mar/2010 and May/2014. Data collection occurred through review of medical charts for presence or absence of DR, determined by an ophthalmologist. Study protocol included demographic characteristics, metabolic control, diabetes mellitus (DM) profile and comorbidities. Statistical analysis used Chi square test for qualitative variables and multivariate logistic regression analysis to select independent variables (SPSS®18.0 software). Odds ratio (OR) was used as measure of association. The study was approved by research ethics committee of UNISUL.

RESULTS

Mean age of group case was 59.5 years with a slight female predominance. Gender, age, body mass index were not associated with outcome. Individuals with poor glycemic control were more likely to DR (OR 3.83; 95 % CI 1.57-9.37). It was observed a positive relationship between duration of DM and DR, with higher chances in 11-15 years of disease (OR 7.52, 95 % CI 3.03-18.68) and >15 years (OR 9.01, 95 % CI 3.58-22.66). Regarding comorbidities, only diabetic nephropathy showed higher chance for DR (OR 3.32; 95 % CI 1.62-6.79).

CONCLUSIONS

Diabetic patients after 10 years of disease with poor glycemic control and nephropathy have a higher chance of DR.

High prevalence of lower extremity peripheral artery disease in type 2 diabetes patients with proliferative diabetic retinopathy

Little is known about the relationship between lower extremity peripheral arterial disease (PAD) and proliferative diabetic retinopathy (PDR) in type 2 diabetes (T2D). Here, we explored the relationship between sight-threatening PDR and PAD. We screened for diabetic retinopathy (DR) and PAD in hospitalized patients with T2D. Patients with a diabetic duration of more than 10 years, HbA1c ≥7.5%, eGFR ≥60mL/min/1.73m2 and with PDR or with no diabetic retinopathy (NDR) were eligible for this cross-sectional study. Severities of DR were graded by digital retinal photographs according to the Early Treatment Diabetic Retinopathy Study (ETDRS) scale. We assessed PAD by measuring Ankle Brachial Index (ABI), Toe Brachial Index (TBI) and Doppler ultrasound. Statistical analyses were performed using SPSS 17.0 software. Of the 1544 patients, 169 patients with extreme eye (57 PDR and 112 NDR) phenotypes met the inclusion criteria. Patients with PDR had a significantly higher proportion of low ABI (≤0.99) and high ABI (≥1.3) than patients with NDR (28.1% and 15.8% vs. 14.3% and 6.2% respectively, P<0.05). PDR patients also had lower TBI than NDR patients (0.56±0.09 vs. 0.61±0.08, P<0.01). The proportion of patients with abnormal duplex ultrasound was higher in PDR than in NDR (21.1% vs. 9.8%, P<0.001). This showed that PDR associated with PAD could be defined in multiple ways: abnormal ABI (≤0.9) (OR = 3.61, 95% CI: 1.15–11.26), abnormal TBI (OR = 2.84, 95% CI: 1.19–6.64), abnormal duplex (OR = 3.28, 95% CI: 1.00–10.71), and critical limb ischemia (OR = 5.52, 95% CI: 2.14–14.26). Moreover, PDR was a stronger independent correlation factor for PAD than a diabetic duration of 10 years. In conclusion, PAD is more common in PDR than in NDR. It implies that PDR and PAD are mostly concomitant in T2D. We should focus on screening PAD in patients with PDR in clinical practice.

An analysis of the association between a polymorphism of KCNJ11 and diabetic retinopathy in a Chinese Han population

Background

Genome-wide association studies (GWAS) have reported that the polymorphism rs5219 of the potassium inwardly rectifying channel, subfamily J, member 11 (KCNJ11) is associated with type 2 diabetes mellitus (T2DM). Given that diabetic retinopathy (DR) is one of the most common microvascular complications of T2DM, GWAS have identified a number of potential susceptibility genes for DR. However, only a fraction of them have been replicated in different studies and show consistent genetic associations with the occurrence of DR. The aim of the present study was to investigate whether common variants of KCNJ11 confer DR in a cohort of the Chinese Han population.

Methods

A case–control study of 580 T2DM patients, including 105 T2DM with DR and 475 T2DM without DR was performed. A single nucleotide polymorphism (SNP) of KCNJ11 (rs5219) was genotyped, and its association with DR was explored using a dominant genetic model. Genotyping was performed by iPLEX technology. Univariate and multivariate logistic regression (MLR) analysis controlling for confounders was conducted to evaluate the association between rs5219 and DR.

Results

The A allele frequency of rs5219 was significantly higher in DR patients than that in the patients without DR (49.01% versus 38.68%, P <0.05). We found the minor A allele could increase the risk to develop DR (ORint = 1.58, 95% CI: 1.139 to 2.192 for allele and P = 0.006, ORint = 1.607, 95% CI: 1.267 to 2.038 for genotype and P <0.001) in the Chinese Han population.

Conclusions

Our findings provided evidence that KCNJ11 was associated with DR in Chinese Han patients with T2DM.

Application of random forests methods to diabetic retinopathy classification analyses

BACKGROUND

Diabetic retinopathy (DR) is one of the leading causes of blindness in the United States and world-wide. DR is a silent disease that may go unnoticed until it is too late for effective treatment. Therefore, early detection could improve the chances of therapeutic interventions that would alleviate its effects.

METHODOLOGY

Graded fundus photography and systemic data from 3443 ACCORD-Eye Study participants were used to estimate Random Forest (RF) and logistic regression classifiers. We studied the impact of sample size on classifier performance and the possibility of using RF generated class conditional probabilities as metrics describing DR risk. RF measures of variable importance are used to detect factors that affect classification performance.

PRINCIPAL FINDINGS

Both types of data were informative when discriminating participants with or without DR. RF based models produced much higher classification accuracy than those based on logistic regression. Combining both types of data did not increase accuracy but did increase statistical discrimination of healthy participants who subsequently did or did not have DR events during four years of follow-up. RF variable importance criteria revealed that microaneurysms counts in both eyes seemed to play the most important role in discrimination among the graded fundus variables, while the number of medicines and diabetes duration were the most relevant among the systemic variables.

CONCLUSIONS AND SIGNIFICANCE

We have introduced RF methods to DR classification analyses based on fundus photography data. In addition, we propose an approach to DR risk assessment based on metrics derived from graded fundus photography and systemic data. Our results suggest that RF methods could be a valuable tool to diagnose DR diagnosis and evaluate its progression.

Plasma plasminogen activator inhibitor-1 is associated with end-stage proliferative diabetic retinopathy in the Northern Chinese Han population

Objective. To identify predictors of end-stage proliferative diabetic retinopathy (PDR) in a cohort of individuals with type 2 diabetes mellitus (T2DM) from the Northern Chinese Han population. Methods. We investigated characteristics of 153 consecutive diabetic patients with end-stage PDR (62 males, 91 females), 123 consecutive PDR patients without end-stage PDR (48 males, 75 females), and 151 normal subjects (63 males, 88 females). Only one eye of each patient or healthy subject was included in this study. Univariate logistic regression models and multivariate logistic regression models were constructed to evaluate the predictors of end-stage PDR. Results. In univariate analysis, systolic blood pressure, diastolic blood pressure, duration of diabetes, family history of T2DM, and plasminogen activator inhibitor-1 (PAI-1) were significently associated with end-stage PDR. After multivariate analysis, family history of T2DM, plasma PAI-1 levels, smoking, and duration of diabetes were four positive predictors associated with end-stage PDR. Conclusions. Higher plasma levels of PAI-1 were associated with end-stage PDR in the Northern Chinese Han population with T2DM.

Prevalence and risk factors for diabetic retinopathy: an Iranian eye study

PURPOSE

The aim of this study was to determine the prevalence of diabetic retinopathy among diabetic patients in Iran and its association with some predisposing factors.

METHODS

All diabetic patients who attended the diabetes clinic underwent ocular examination, including slit-lamp biomicroscopy. The blood pressure and blood biochemical parameters were then measured.

RESULTS

The prevalence of diabetic retinopathy among 1022 diabetic participants was 23.6% (241 cases). This study showed that there is a statistically significant relation between diabetic retinopathy and mean blood pressure, fasting blood sugar, blood urea nitrogen, and level of HbA1c. There was no difference in lipid profile between patients with and without retinopathy. The duration of diabetes was a predicting factor for retinopathy as well as presence of renal and cardiovascular diseases and fasting glucose >126 as independent variables.

CONCLUSIONS

The duration of diabetes was the most important risk factor for progression of retinopathy.

Prevalência de retinopatia diabética em pacientes atendidos pela Estratégia Saúde da Família no município de Ananindeua - PA

Objetivo: Identificar a prevalência de retinopatia diabética (RD) em pacientes atendidos pela Estratégia Saúde da Família (ESF) de Ananindeua, Pará. Métodos: Este é um estudo do tipo seccional com 40 pacientes portadores de Diabetes Mellitus (DM) cadastrados no programa HIPERDIA e assistidos pela ESF de Ananindeua. Os selecionados foram submetidos a um questionário padronizado domiciliar e responderam questões quanto ao conhecimento, evolução e complicações do DM e da RD, além de dados socioeconômicos. Na etapa seguinte, um médico oftalmologista voluntário realizou fundoscopia e detectou os portadores da RD que, em seguida, foram encaminhados para um centro especializado para receber o tratamento específico. Desses pacientes, 9 foram excluídos da pesquisa por não comparecerem na unidade para realizar a fundoscopia. Resultados: A prevalência de RD encontrada foi de 40,7%, sendo que 4 pacientes tiveram sua análise prejudicada devido à presença de catarata, portanto só foi possível fazer avaliação em 27. Fatores associados com RD, após análise das variáveis, foram: tempo de conhecimento do diagnóstico de ser portador de DM, tipo de DM e RD não proliferativa. Conclusão: Este estudo piloto ressalta a importância da atenção primária no acompanhamento dos pacientes diabéticos, e da orientação aos servidores da saúde pública quanto à necessidade do encaminhamento periódico dos diabéticos ao oftalmologista.

Papel do fator de crescimento vascular endotelial na angiogênese e na retinopatia diabética

A retinopatia diabética (RD) é uma complicação microvascular do diabetes melito, sendo importante causa de cegueira adquirida. Fatores angiogênicos, como o vascular endothelial growth factor (VEGF), estão envolvidos na patogênese da RD. O VEGF-A é uma citocina potente e multifuncional que atua por meio dos receptores VEGFR-1 e VEGFR-2 expressos no endotélio vascular causando aumento da permeabilidade vascular e estímulo à neovascularização em processos fisiológicos e patológicos. O VEGFR-2 é o principal mediador mitogênico, angiogênico e do aumento da permeabilidade vascular. Alguns polimorfismos do VEGF têm sido estudados na suscetibilidade e risco de progressão da RD. Importante associação entre o polimorfismo 634C/G e a presença de RD é relatada principalmente em relação ao alelo C. A homozigose CC estaria relacionada à RD proliferativa (RDP) e a níveis sérico e vítreo aumentados de VEGF, sugerindo que a presença do alelo C seja um fator de risco independente para RD. Os conhecimentos sobre o VEGF levaram ao desenvolvimento de agentes antiVEGF com o objetivo de inibir a neovascularização patológica e são uma realidade na prática médica do tratamento da RD.

Absence of diabetic retinopathy in a patient who has had diabetes mellitus for 69 years, and inadequate glycemic control: case presentation

The main risk factors for the development and progression of diabetic retinopathy (DR) are chronic hyperglycemia, disease duration and systemic blood pressure. So far chronic hyperglycemia is the strongest evidence concerning the risk of developing DR. However there are some patients with poor metabolic control who never develop this diabetic complication. We present a case of a 73-year-old woman with type 1 diabetes mellitus, diagnosed 69 years ago. The patient is 73 years old, with no evidence of DR, despite poor glycemic control and several risk factors for DR. This case suggests the presence of a possible protection factor, which could be genetic.