Neurovascular Coupling in Cognitive Impairment Associated With Diabetes Mellitus

Abstract

Although it is feared that diabetes-induced cognitive decline will become a major clinical problem worldwide in the future, the detailed pathological mechanism is not well known. Because patients with diabetes have various complications of vascular disease, with not only macrovascular but also microvascular disorders, vascular disorders in the brain are considered to be one of the mechanisms in diabetes-induced cognitive impairment. Indeed, disruption of the blood - brain barrier (BBB) has been observed in some diabetic patients and experimental diabetes models. Moreover, white matter lesions, part of the evidence of BBB dysfunction, are reported to be observed more frequently in patients with diabetes. Animal studies demonstrate that diabetes enhances BBB permeability through a decrease in the level of tight junction proteins and an increase in matrix metalloproteinase activity. However, there are several reports indicating that BBB disruption does not occur with diabetes. Therefore, the association of BBB breakdown with diabetes-induced cognitive impairment is not conclusive. Recently, neuronal diseases involving dementia have been induced experimentally through dysfunction of neurovascular coupling, which involves blood vessels, astrocytes and neutrons. Diabetes-induced cognitive decline may be induced via disruption of neurovascular coupling, with not only vascular disorder but also impairment of astrocytic trafficking. Here, the relation between vascular disorder and cognitive impairment in diabetes is discussed. (Circ J 2011; 75: 1042 - 1048

NOX2 deficiency attenuates markers of adiposopathy and brain injury induced by high-fat diet

“…In addition to loss of BBB integrity, there is increasing evidence that hypoperfusion and/or loss of neurovascular coupling may be a key pathway whereby oxidative stress connects vascularrelated diseases to cognitive impairment (45,55). Indeed, evidence suggests that diabetes-induced cognitive decline may be induced via disruption of neurovascular coupling, with physiological impairment arising from both cerebrovascular elements and also glial cells (61,83). In this light, it is important to note that NADPH oxidase is a major player in both endothelial and glial physiology.…”

Altered Spontaneous Brain Activity in Type 2 Diabetes: A Resting-State Functional MRI Study

“…The abnormalities of spontaneous brain activity reflected by ALFF and ReHo measurements in the absence of structural changes in T2DM patients may provide insights into the neurological pathophysiology underlying diabetes-associated cognitive decline. Type 2 diabetes mellitus (T2DM) has been shown to be associated with an increased risk of cognitive impairment (1,2), which primarily manifests as declining memory, information processing speed (3), attention, and executive function (4). However, the pathophysiological mechanism of T2DM-induced cognitive impairment is still largely unknown (5).…”

Assessment of the Cognitive Status in Diabetes Mellitus

“…Whatever the mechanism, with an expected increase in the prevalence of diabetes in people of all ages, which include the older adults, the risk of developing dementia may increase [23]. A diabetes-induced cognitive decline may be induced via the disruption of the neurovascular coupling, not only with vascular disorders but also with the impairment of the astrocytic trafficking [24]. It was observed in our study, that the educational qualification affected the MMSE and the 3MS scores.…”