Chronically Impaired Autoregulation of Cerebral Blood Flow in Long-Term Diabetics

Abstract

Abstract:Chronically Impaired Autoregulation of Cerebral Blood Flow in Long-Term Diabetics • Using the arteriovenous oxygen difference method autoregulation of cerebral blood flow (CBF) was tested in 16 long-term diabetics and eight control patients. Blood pressure was raised by angiotensin infusion and lowered by trimethaphan camsylate infusion, in some cases combined with head-up tilting of the patient. Regression analysis was carried out on the results in order to quantify autoregulatory capacity.In the control patients CBF did not vary with moderate blood pressure variations, indicating normal autoregulation. In four of the 16 diabetic patients CBF showed significant pressure dependency, indicating impaired autoregulation. The cause of impaired autoregulation in some long-term diabetics is believed to be diffuse or multifocal dysfunction of cerebral arterioles due to diabetic vascular disease. Other conditions with impaired autoregulation are discussed and compared with that seen in long-term diabetes.

Impaired autoregulation of blood flow in skeletal muscle and subcutaneous tissue in long-term type 1 (insulin-dependent) diabetic patients with microangiopathy

“…In diabetic subjects cerebral blood flow is less rigidly controlled than in normal subjects, suggesting impaired autoregulation [12,13]. Apart from this no information is available on autoregulation in diabetes.…”

“…Arteriolar tone is influenced by local changes in concentrations of various metabolites including adenosine [7], pyrophosphate [8] and potassium [9]. Furthermore, local changes in oxygen [10] and carbon dioxide tensions [11] may play an important role.In diabetic subjects cerebral blood flow is less rigidly controlled than in normal subjects, suggesting impaired autoregulation [12,13]. Apart from this no information is available on autoregulation in diabetes.…”

Glucose-induced downregulation of angiotensin II and arginine vasopressin receptors in cultured rat aortic vascular smooth muscle cells. Role of protein kinase C.

“…Early diabetes mellitus in both experimental animals and man is associated with increased blood flow to many tissues, including the kidney, myocardium, retina, skin, muscle, and brain (1)(2)(3)(4)(5)(6)(7). These early changes in regional hemodynamics have in turn been strongly implicated in the pathogenesis of the widespread microvascular injury that characterizes this disease (8)(9)(10).…”

A simple deep breathing test reveals altered cerebral autoregulation in type 2 diabetic patients

“…Thus, the autoregulatory disturbances in our patients were relatively subtle. Previous studies have also reported relatively mild alterations in cerebral blood flow autoregulation in patients with diabetes [16,17]. In some diabetic patients, impaired autoregulation might contribute to orthostatic hypotension [9], which is a known risk factor for ischaemic stroke [18].…”