Retinal Blood Flow in Type 1 Diabetic Patients With No or Mild Diabetic Retinopathy During Euglycemic Clamp

Background/objectives: Continuous subcutaneous insulin infusion (CSII) is a treatment for type 1 diabetes that improves metabolic control and reduces micro and macrovascular complications. The aim of this study was to compare the effect of CSII versus traditional multiple daily injections (MDI) therapy on retinal vasculature. Methods: We performed a prospective study with type 1 diabetic patients with no prior history of ocular pathology other than mild diabetic retinopathy. The patients were divided into two groups according to their therapeutic modality (CSII vs MDI). The retinal nerve fiber layers thickness and vascular densities were compared between groups in both macula and optic disc. The correlations between vascular density and clinical features were also determined. Statistical significance was defined as p < 0.05. Results: The study included 52 eyes, 28 in the insulin CSII group. The mean age was 36.66 ± 12.97 years, with no difference between groups ( p = 0.49). The mean glycated hemoglobin (HbA1c) was found to be lower in the CSII group (7.1% ± 0.7 vs 7.5% ± 0.7 p < 0.01). The parafoveal vascular density was found to be higher in the CSII group (42.5% ± 0.4 vs 37.7% ± 0.6, p < 0.01). We found an inverse correlation between HbA1c value and parafoveal vascular densities ( p < 0.01, r = −0.50). Conclusion: We found that CSII provided better metabolic control than MDI and this seemed to result in higher parafoveal vascular density. As lower vascular density is associated with an increased risk of diabetic retinopathy, these results suggest that CSII could be the safest therapeutic option to prevent retinopathy.

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Decreased distensibility of resistance vessels of the skin in type 1 (insulin-dependent) diabetic patients with microangiopathy

Clinical Science ◽

10.1042/cs0720123 ◽

1987 ◽

Vol 72 (1) ◽

pp. 123-130 ◽

Cited By ~ 15

Author(s):

J. Kastrup ◽

T. Nørgaard ◽

H.-H. Parving ◽

N. A. Lassen

Keyword(s):

Blood Flow ◽

Inverse Correlation ◽

Diabetic Patients ◽

Resistance Vessels ◽

Head Up Tilt ◽

Insulin Dependent ◽

Insulin Dependent Diabetic ◽

Type 1 Diabetic Patients ◽

Term Type

1. The distensibility of the resistance vessels of the skin at the dorsum of the foot was determined in 11 long-term type 1 (insulin-dependent) diabetic patients with nephropathy and retinopathy, nine short-term type 1 diabetic patients without clinical microangiopathy and in nine healthy non-diabetic subjects. 2. Blood flow was measured by the local 133Xexenon washout technique in a vascular bed locally paralysed by the injection of histamine. Blood flow was measured before, during and after a 40 mmHg increase of the vascular transmural pressure, induced by head-up tilt. 3. The mean increase in blood flow during headup tilt was only 24% in diabetic subjects with and 48% in diabetic patients without clinical microangiopathy, compared with 79% in normal non-diabetic subjects (P < 0.0005 and P < 0.05, respectively). 4. An inverse correlation between microvascular distensibility and degree of hyalinosis of the terminal arterioles in biopsies from the skin was demonstrated (r = − 0.57, P < 0.001). 5. Our results suggest that terminal arteriolar hyalinosis reduces the microvascular distensibility and probably increases the minimal vascular resistance, thereby impeding hyperaemic responses.

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