Aims/hypothesis: Elevated high-sensitivity C-reactive protein (hsCRP) concentrations indicate increased risk of future coronary events. The association between hsCRP and coronary vasoreactivity has not yet been examined in type 1 diabetic subjects.
Methods: We studied 18 young men who were non-smokers and who had uncomplicated type 1 diabetes. The diabetic subjects were divided into two groups, according to their median hsCRP concentration, as follows: (i) subjects with slightly elevated hsCRP (median 0.76 mg/l, range 0.47-4.73 mg/l, n=8); and (ii) subjects with low hsCRP (median 0.32 mg/l, range 0.11-0.35 mg/l, n=10). In addition we investigated 22 non-diabetic age-matched subjects (hsCRP: median 0.42 mg/l, range 0.11-1.31 mg/l). Resting myocardial blood flow and hyperaemic adenosine-stimulated flow during euglycaemic-hyperinsulinaemic clamp were determined using positron emission tomography and oxygen-(15)-labelled water.
Results: Diabetic subjects with slightly elevated hsCRP had significantly higher hsCRP concentrations than non-diabetic subjects (p=0.008). Resting myocardial blood flow was similar (NS) in diabetic subjects with slightly elevated hsCRP (0.79+/-0.19 ml.g(-1).min(-1)) or low hsCRP (0.81+/-0.15 ml.g(-1).min(-1)) and non-diabetic subjects (0.80+/-0.19 ml.g(-1).min(-1)). Adenosine infusion induced a significant increase in blood flow in all study subjects (p<0.001) but was blunted in diabetic subjects with slightly elevated hsCRP (3.42+/-0.61 ml.g(-1).min(-1)) when compared with diabetic subjects with low hsCRP (5.08+/-1.65 ml.g(-1).min(-1), p=0.02) or non-diabetic subjects (4.51+/-1.36 ml.g(-1).min(-1), p=0.04). Adenosine-stimulated flow was inversely correlated with hsCRP concentrations in all diabetic subjects (r=-0.70, p=0.001).
Conclusions/interpretation: In young subjects with uncomplicated type 1 diabetes, even slightly elevated hsCRP concentrations are associated with reduced coronary vasoreactivity.