Glycosylated hemoglobin and diabetic retinopathy

Estimation of glycosylated hemoglobin (HbA1c) levels by modified Fluckinger and Winterhalter's method was done in 25 normal persons, 25 diabetic patients without retinopathy, and 25 diabetic patients with retinopathy. The HbA1c values were significantly higher in diabetic patients with or without retinopathy than in the control group (P less than .001). In diabetic patients with retinopathy, the mean value of HbA1c was higher in proliferative retinopathy than in background retinopathy, but statistical analysis showed this was not significant (P greater than .6).     

糖化血红蛋白及视觉电生理检测在糖尿病视网膜病变早期诊断的价值

目的:研究糖尿病性视网膜病变(diabetic retinopathy,DR)时糖化血红蛋白(hemoglobin A1c,HbA1c)及视网膜振荡电位(oscillatory potentials,Op)的动态变化。方法:对确诊的2型糖尿病患者用检眼镜检查进行筛选,以眼底荧光素血管造影(fundus fluorescein angiography,FFA)进行明确分期,对各期患者在3a内定期行HbA1c测定6次,行Op检查2次,最后1次检测配合FFA检查,统计分析结果。结果:HbA1c水平控制在4.99%±0.58%为预防DR发生发展的安全参考值;HbA1c水平持续在9.77%±1.57%时,DR进展明显加快;Op总波幅下降副度<10.6±4.9μV可作为预测视网膜病变未进展的参考值;Op总波幅下降幅度>31.6±9.7μV,则可作为预测2型糖尿病患者发生DR或DR发生进展的依据。结论:HbA1c,OP结合,能预测DR的发展。     

Preproliferative diabetic retinopathy sub-classification and glycemic control--relationship between mean hemoglobin A1C value and development of proliferative diabetic retinopathy]

PURPOSE: We evaluated the relationship between long-term glycemic control and the proportion of patients developing proliferative diabetic retinopathy(PDR) in cases of mild preproliferative diabetic retinopathy(PPDR). MATERIALS AND METHODS: We evaluated the relationship between the mean hemoglobin A1C (HbA1C) value during a period of at least 2 years and the proportion of patients developing PDR in cases of mild PPDR, based on our previously proposed subclassification. RESULTS: During follow-up, 27% of all cases developed PDR. The mean HbA1C value in these cases was 9.4%, which was significantly higher than the 7.6% in cases which had not developed PDR. The proportion of patients developing PDR was 48% in cases with a mean HbA1C value 8.6% or more. In contrast, the proportion was 8% in cases with a mean HbA1C value below 8.6%. It was estimated that the proportion of patients developing PDR will approximately double if the mean HbA1C value increases by one percent. The cumulative occurrence rates of PDR at two, 5, and 10 years were estimated to be 5, 28, and 60% in cases with a mean HbA1C value 8.6% or more and 0, 7, and 10% in cases with a mean HbA1C value below 8.6%, respectively. CONCLUSION: Based on the above results, we conclude that more strict systemic and ophthalmological control is indicated for patients with a mean HbA1C value exceeding 8.6%.     

检测糖化血红蛋白对糖尿病视网膜病变的临床意义

目的:探讨糖化血红蛋白对糖尿病视网膜病变的临床意义。方法:对本院158例2型糖尿病患者做眼底检查和荧光眼底血管造影检查,分为糖尿病正常眼底(NDR)组83例,糖尿病视网膜病变(DR)组75例,进行糖化血红蛋白(HbA1c)、空腹血糖(FBG)检测。结果:DR组HbA1c值明显高于NDR组(P<0.01),而FBG水平在DR组与NDR组无显著性差异。结论:HbA1c是DR的一个重要检测指标。     

C-反应蛋白、糖化血红蛋白与2型糖尿病视网膜病变的关系

目的探讨2型糖尿病患者(T2DM)中C-反应蛋白(CRP)和糖化血红蛋白(HbA1C)与糖尿病视网膜病变(DR)的关系。方法随即分组,检测20例正常对照组、20例糖尿病无视网膜病变(NDR)、20例非增生性糖尿病视网膜病变(NPDR)和20增生性糖尿病视网膜病变(PDR)患者中血清中CRP和HbA1C含量,并分析各组变化。结果 T2DM患者CRP和HbA1C随着DR的病变程度逐步增加,差异有显著性(P<0.05),两者之间成正相关。结论 CRP和HbA1C是DR发生、发展的危险因素,并能预测DR的风险和严重程度。     

Subclassification of preproliferative diabetic retinopathy and glycemic control: relationship between mean hemoglobin A1C value and development of proliferative diabetic retinopathy

PURPOSE: We evaluated the relationship between long-term glycemic control and the proportion of patients developing proliferative diabetic retinopathy (PDR) among cases with mild type preproliferative diabetic retinopathy (PPDR). METHODS: The relationship was evaluated between the mean hemoglobin A1C (HbA1C) value during a period of at least 2 years and the proportion of patients developing PDR among cases with mild type PPDR, based on our previously proposed subclassification. RESULTS: During follow-up, 27% of the total PPDR cases developed PDR. The mean HbA1C value in those patients who had developed PDR was 9.4% and was significantly higher than the 7.6% in those who had not developed PDR. The proportion developing PDR was 48% of the cases with a mean HbA1C value of 8.6% or more. By comparison, the proportion developing PDR was 8% among those with a mean HbA1C value below 8.6%. The proportion developing PDR was estimated to approximately double with each 1% increase in the mean HbA1C value. The cumulative occurrence rates of PDR at 2, 5, and 10 years were estimated to be 5%, 28%, and 60% in cases with a mean HbA1C value of 8.6% or more, and 0%, 7%, and 14% in those with a mean HbA1C value below 8.6%, respectively. CONCLUSION: Stricter systemic and ophthalmological control is indicated for cases with a mean HbA1C value exceeding 8.6%.     

Microalbuminuria and low hemoglobin as risk factors for the occurrence and increasing severity of diabetic retinopathy

Aim:

To assess the influence of urinary microalbuminuria and hemoglobin concentration on the occurrence and severity of diabetic retinopathy (DR), clinically significant macular edema (CSME) and hard exudate formation.

Materials and Methods:

In this prospective cross-sectional study carried out over a period of 2 years, type 2 diabetic patients seeking ocular evaluation for DR were assessed for presence and severity of DR, presence of hard exudates and CSME. Retinal findings were correlated to severity of microalbuminuria, hemoglobin concentration and other systemic risk factors using linear regression analysis.

Results:

Three hundred and six patients were included in the study. DR of any grade was seen in 132 (43%) patients, hard exudate formation in 93/306 (30.4%) patients, CSME in 50/306 (16.3%) patients and proliferative DR in 26/306 (8.5%) patients. Duration of diabetes (P <0.001), microalbuminuria (P <0.001) and low hemoglobin (P = 0.001) were found to be highly significant risk factors for the development and increasing severity of DR as well as for CSME and hard exudate formation.

Conclusion:

Microalbuminuria and low hemoglobin are strong predictors for DR, CSME and hard exudate formation in type 2 diabetics even after correcting for duration of diabetes and other systemic risk factors. Although not directly involved in the pathogenesis, microalbuminuria can help in identifying patients at risk for more severe diabetic eye disease. Microalbuminuria warrants intensive monitoring of both retinal and renal status. The hemoglobin levels should be monitored regularly in diabetic patients to detect and treat anemia, thereby reducing one risk factor for DR.     

趋化因子与糖尿病视网膜病变

随着全球糖尿病患者的增多,糖尿病视网膜病变(diabetic retinopathy,DR)已成为世界性致盲原因之一,除了高血糖这一始动因素外,多种细胞因子构成复杂网络系统导致血-视网膜屏障(blood-retinal barrier,BRB)的破坏及新生血管的生成,是维持糖尿病视网膜病变发生发展的主要病理基础,我们主要就众多细胞因子中的趋化因子与DR发病关系的研究进展进行综述。     

Somatomedin-C and diabetic retinopathy

To investigate the relationship between the plasma somatomedin-C level and diabetic retinopathy, especially in different stages of the disease, plasma somatomedin-C levels were measured in 72 patients with noninsulin-dependent diabetes mellitus accompanied by or without retinopathy and in 37 normal control subjects. The stage of retinopathy was assessed by ophthalmoscopy and fluorescein angiography. Plasma somatomedin-C levels were significantly greater in the diabetic patients with retinopathy than in the age-matched normal controls (P less than 0.01). Plasma somatomedin-C level in the patients with proliferative retinopathy was 0.60 +/- 0.30 (mean +/- SD) IU/ml (n = 24), which was significantly greater than that in the normal controls (0.41 +/- 0.18 IU/ml) (P less than 0.01). However, the patients in different stages of diabetic retinopathy did not differ significantly from each other in their plasma somatomedin-C levels.     

Genes and diabetic retinopathy

Several recent studies have provided evidence that good diabetes control is important to prevent diabetic retinopathy. However, some groups of patients develop diabetic retinopathy despite good control and others escape retinopathy despite poor control. This suggests the role of genetic factors in susceptibility to retinopathy. This article reviews the role of genetic factors in determining diabetic retinopathy.     

Haemodynamics and diabetic retinopathy

Diabetic retinopathy is the most common cause of blindness in adults in all industrialised countries. A much better pathophysiological understanding of the disease has been achieved during the last years. There is evidence that a functional deficit in haemodynamics proceeds the morphological changes of the retina. Modern technologies for measuring haemodynamic parameters and their correlation to pathophysiology in diabetic retinopathy are discussed. In the near future it will be possible to use these parameters as an early sign of worsening before morphological changes occur. Measurement of the therapeutic success, e. g., in laser coagulation would seem to be possible.     

Anemia and diabetic retinopathy

Three patients (a 44-year-old woman, a 65-year-old man, and a 39-year-old woman) who had had diabetes mellitus for an average of 17 years had good vision and mild to moderate background diabetic retinopathy. These patients developed severe iron deficiency anemia from varying causes and their conditions rapidly progressed to a severe proliferative phase that necessitated panretinal photocoagulation and pars plana vitrectomy in two cases.     

C肽与糖尿病视网膜病变

在过去的20a里,虽然不是所有的学者都认可,但很多通过人或动物的研究都表明,C肽在防止和逆转糖尿病的某些并发症方面发挥着重要作用。此综述的目的就是简要介绍C肽的作用及其作用机理,详细介绍目前有关C肽对糖尿病视网膜病变影响的认识。     

同型半胱氨酸与糖尿病视网膜病变的相关性

同型半胱氨酸（Hcy）是一种与半胱氨酸同系的四碳含硫氨基酸，在细胞内由蛋氨酸代谢脱去甲基后形成，是蛋氨酸代谢的中间产物。近年来，越来越多的研究表明同型半胱氨酸是一种反应性血管损伤氨基酸，具有细胞毒性，与微血管疾病如糖尿病视网膜病变（DR）存在着密切的关系。Hcy可通过氧化应激系统影响血管内皮的功能，促进低密度脂蛋白过氧化，造成细胞结构和功能的破坏，通过诱导多种趋化因子、黏附分子等在体内的表达，而导致微血管疾病的发生。就Hcy与DR发病的相关性及其发病机制的研究现状进行综述。     

氨基胍与糖尿病视网膜病变

糖尿病视网膜病变是严重的致盲眼病，氨基胍通过抑制蛋白非酶糖基化终末产物形成、一氧化氮合酶活性、对半卡巴肼敏感的胺氧化酶活性、毛细血管内白细胞粘滞、血管内皮生长因子以及抑制醛糖还原酶、防止低密度脂蛋白氧化修饰等途径来改善糖尿病视网膜病变。