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.