The regulatory mechanisms for the skin microcirculation appear to be different from forearm blood flow , and responses in these two vascular territories do not normally correlate in healthy individuals [7,8]. Thus, abnormalities in forearm blood flow, which many use as a “gold standard” endothelial assessment tool, may not be reflected in the microvasculature, and, conversely, microvascular dysfunction may not be observed by any assessment of large
or resistance vascular MG-132 supplier function. Type 2 diabetes is an important cardiovascular risk factor and has been demonstrated to have a similar impact on morbidity and mortality as a cardiovascular event . Microvascular damage has been recognized in patients with diabetes for at least 40 years . Microangiopathy appears to precede the development of cardiovascular events in those with diabetes , and changes in microvascular function appear to precede this microangiopathy [45,63]. In type 1 diabetes, these abnormalities take several years to develop and AZD1208 appear to be proportional to glycemic control . In type 2 diabetes, however, the impairment is evident at diagnosis, in normoglycemic women who were previously diagnosed with gestational diabetes , and in normoglycemic individuals at risk of developing
type 2 diabetes . The epidemiological link has been strengthened by interventional work, demonstrating improvement in skin microvascular hyperemic responsiveness with good glycemic control over a 12-month period [11,29]. This association was very strongly associated with degree of improvement of glycemic control (R2 between percentage increase in HbA1C and increase in maximum hyperemia = 0.53). However, the support for this being a mechanism for improvement in cardiovascular event rate with good
glycemic control has been challenged by the observation that the P-PAR γ antagonist, rosiglitazone, improves nitric oxide-dependent skin microvascular responsiveness, independent of changes in glycemic control , whilst at the same time apparently increasing the cardiovascular event rate . An interesting observation in the latter work however, was that, whilst the Chlormezanone risk of myocardial infarction was increased with rosiglitazone therapy, there was a trend toward fewer strokes, that has subsequently been confirmed in alternative studies. Hypertension, another important pathogenic associate of vascular disease, is known to be associated with endothelial dysfunction in both the muscles’ vascular bed and skin microcirculation [44,47]. One implicated mechanism is the activation of cyclooxygenase, which reduces the availability of nitric oxide by production of oxidative stress . There are several other studies, however, suggesting an inherited component.