Residual B-cell function in insulin-dependent (type I) diabetics with and without retinopathy

Abstract

In order to evaluate if residual B-cell function is a protecting factor against the development of diabetic retinopathy in type I diabetics we measured C-peptide levels before and after glucagon stimulation (1 mg i.v.) in 74 type I diabetics. In all patients retinopathy was assessed by fluorescein angiography and retinal lesions were classified as: grade 0, normal; grade 1, background retinopathy; grade 2, proliferative retinopathy. We then correlated the degree of retinopathy to sex, age, duration of diabetes, smoking, percentage of ideal body weight, systolic and diastolic blood pressure, serum cholesterol, triglycerides, creatinine and C-peptide by means of multiple linear regression analysis. Twenty-three out of 74 type I diabetics had retinopathy. In all 7 subjects with proliferative retinopathy duration of diabetes exceeded 10 years. There was significant correlation between retinopathy and duration of diabetes (r = 0.373, p less than 0.001). No correlation was found between retinopathy and all the other variables, in particular between retinopathy and basal C-peptide or C-peptide increment (delta). An inverse correlation was found between the increment of C-peptide and duration of diabetes (r = -0.404, p less than 0.01). Our data show that residual B-cell function cannot be considered a protecting factor against the development of diabetic retinopathy.

Epidemiology of Proliferative Diabetic Retinopathy

“…The relationship of endogenous insulin secretion, independent of glycemic control, to the development of proliferative diabetic retinopathy and other complications is unclear (58)(59)(60)(61)(62)(63)(64)(65). Some studies suggest a protective effect of remaining endogenous insulin secretion (58-62), whereas others do not (63)(64).…”

Implicações clínicas da persistência de anti-GAD positivo e peptídeo C detectável em pacientes com diabetes melito tipo 1 de longa duração

“…No subgrupo de indivíduos jovens em insulinoterapia, com provável DM1, não foi identificada nenhuma associação entre níveis de PC e a frequência ou gravidade da retinopatia diabética (27). Outros estudos também foram incapazes de demonstrar papel protetor da preservação do PC no desenvolvimento de retinopatia ou outras complicações crônicas do DM1 (28,29).…”

Understanding Pancreatic Secretion in Type 1 Diabetes

“…Other studies also found no influence of CP stimulated with the development of retinopathy, neuropathy and/or microalbuminuria in T1DM. However, these studies included a small number of patients, with short time for monitoring and/or few chronic complications (100)(101)(102). In the pathological study of Meier et al, the number of cells found in patients with T1DM was not associated with the disease duration, but rather with glycemic control, being higher at lower blood glucose levels (90).…”