Glucose metabolism and resistance arteries in essential hypertension

Background and Aim: To evaluate the involvement of impaired glucose tolerance in the pathological enlargement of the heart that commonly occurs in essential hypertension and to assess a possible role for impaired glucose tolerance in the abnormalities of small artery structure that have been reported in hypertension. Methods and Results: We studied 19 men (11 Caucasian, 5 Afro-Caribbean and 3 Asian) with essential hypertension and on no treatment for at least 3 months. None had diabetes mellitus or other metabolic disease. All subjects had blood glucose and insulin measured before and for 2 hours after a standard 75g oral glucose load. Dimensions of small arteries were studied on a small vessel myograph and corrected for stretch artefact. In the 19 subjects, there was no significant relationship between media thickness of small arteries and basal levels or area under the curve for glucose or insulin. Furthermore, there was no significant association between media-lumen ratio and parameters of insulin metabolism before and following a 75g oral glucose load. In contrast, media to lumen ratio was increased in subjects with greater 1-hour or 2-hour glucose levels as well as area under the curve (AUC-G) for glucose after a 75g glucose load (r= 0.541, p<0.017 for AUC-G vs media:lumen ratio). Conclusions: These findings suggest that impaired glucose tolerance may be a factor in small artery changes in human essential hypertension.