von Willebrand factor and early diabetic retinopathy: no evidence for a relationship in patients with Type 1 (insulin-dependent) diabetes mellitus and normal urinary albumin excretion

High plasma levels of von Willebrand factor, an indicator of endothelial cell dysfunction, have been reported in both diabetic retinopathy and nephropathy. It is unclear, however, whether von Willebrand factor is related to diabetic retinopathy in the absence of diabetic nephropathy. The relationship between retinal status and plasma von Willebrand factor concentration was investigated in a cohort of 17 patients with Type 1 (insulin-dependent) diabetes mellitus who were followed-up for a median of 42 months. The patients were examined three times. They were selected for having had normal urinary albumin excretion and no evidence of retinopathy (on fundoscopy) at the first and second examination. They were then divided into two groups, according to absence (Group A;n=9) or presence (Group B;n=8) of retinopathy on fundoscopy or fluorescein angiography at the third examination. Urinary albumin excretion remained normal in all patients. Plasma von Willebrand factor levels were similar in both groups: (median) 128 vs 123 %, 164 vs 132% and 159 vs 130 % (first, second and third examination, respectively). Median changes in plasma von Willebrand factor were also similar: +7 vs +9 % and +5 vs +1 % (first-second and second-third examination). Patients in whom the plasma von Willebrand factor concentration increased had higher systolic blood pressure at the third examination (150±30 vs 130±12 mmHg,p=0.02) when compared to those in whom plasma von Willebrand factor did not increase, but were of similar age and had similar diabetes duration, retinal status, diastolic blood pressure, glycated haemoglobin and serum cholesterol concentration. These data do not support the hypothesis that increases in plasma von Willebrand factor concentration reflect retinal endothelial injury in Type 1 diabetic patients with normal urinary albumin excretion. In these patients, high or increasing plasma von Willebrand factor levels may be related to systolic blood pressure

Homocysteine, S-adenosylmethionine and S-adenosylhomocysteine are associated with retinal microvascular abnormalities: the Hoorn Study

A B S T R A C T The aim of the present study was to investigate the relationship between homocysteine and homocysteine metabolism components and retinal microvascular disorders in subjects with and without Type 2 diabetes. In this population-based study of 256 participants, aged 60-85 years, we determined total plasma homocysteine, SAM (S-adenosylmethionine) and SAH (S-adenosylhomocysteine) in plasma and erythrocytes, total folate in serum and erythrocytes, 5-MTHF (5-methyltetrahydrofolate), and vitamins B12 and B6. Participants were examined ophthalmologically by means of indirect funduscopy and two-field 45 • fundus photography, and were graded for retinopathy and retinal sclerotic vessel abnormalities. A computer-assisted method was used to measure retinal vessel diameters. Total plasma homocysteine was inversely associated with retinal arteriolar diameters {standardized β, − 0.20 [95 % CI (confidence interval), − 0.33 to − 0.07]} or a decrease of 3.78 μm CRAEs (central retinal arteriolar equivalents) per 1 S.D. increase in homocysteine level (= 4.6 μmol/l). In addition, the SAM/SAH ratio in plasma was inversely associated with retinal sclerotic vessel abnormalities and retinopathy [odds ratios, 0.61 (95 % CI, 0.39-0.96) and 0.50 (95 % CI, 0.30-0.83) per 1 S.D. respectively]. The associations were independent of age, sex, glucose tolerance status, other homocysteine metabolism components and cardiovascular risk factors. In conclusion, the results of the present study support the concept that total plasma homocysteine and a low SAM/SAH ratio in plasma, which may reflect reduced transmethylation reactions, may contribute to the pathogenesis of (retinal) microangiopathy

Homocysteine, S-adenosylmethionine and S-adenosylhomocysteine are associated with retinal microvascular abnormalities: the Hoorn Study

The aim of the present study was to investigate the relationship between homocysteine and homocysteine metabolism components and retinal microvascular disorders in subjects with and without Type 2 diabetes. In this population-based study of 256 participants, aged 60-85 years, we determined total plasma homocysteine, SAM (S-adenosylmethionine) and SAH (S-adenosylhomocysteine) in plasma and erythrocytes, total folate in serum and erythrocytes, 5-MTHF (5-methyltetrahydrofolate), and vitamins B12 and B6. Participants were examined ophthalmologically by means of indirect funduscopy and two-field 45° fundus photography, and were graded for retinopathy and retinal sclerotic vessel abnormalities. A computer-assisted method was used to measure retinal vessel diameters. Total plasma homocysteine was inversely associated with retinal arteriolar diameters {standardized β, -0.20 [95% CI (confidence interval), -0.33 to - 0.07]} or a decrease of 3.78 μm CRAEs (central retinal arteriolar equivalents) per 1 S.D. increase in homocysteine level (= 4.6 μmol/l). In addition, the SAM/SAH ratio in plasma was inversely associated with retinal sclerotic vessel abnormalities and retinopathy [odds ratios, 0.61 (95% CI, 0.39-0.96) and 0.50 (95% CI, 0.30-0.83) per 1 S.D. respectively]. The associations were independent of age, sex, glucose tolerance status, other homocysteine metabolism components and cardiovascular risk factors. In conclusion, the results of the present study support the concept that total plasma homocysteine and a low SAM/SAH ratio in plasma, which may reflect reduced transmethylation reactions, may contribute to the pathogenesis of (retinal) microangiopathy. © The Authors

Photography or Ophthalmoscopy for Detection of Diabetic Retinopathy?

The U.K. National Screening Committee recommended digital fundus photography as the screening method of choice for diabetic retinopathy (DR). However, concerns have been expressed about replacing ophthalmoscopy with slit-lamp biomicroscopy by digital photography. These concerns included the possibility of missing peripheral and stereoscopic visible retinal lesions; increased chance of a technical failure compared with ophthalmoscopy, resulting in more reexaminations; and higher cost (1). New data from our study of 453 patients with diabetes, aged 31–86 years, highlight the need for a careful consideration of the retinal area photographed and the minimal resolution of images to detect DR