The association of plasma adiponectin levels with hypertensive retinopathy

Previous studies have demonstrated that low plasma adiponectin concentrations are associated with essential hypertension. It has also recently been shown that adiponectin plays an essential role in the modulation of angiogenesis. These data led us to hypothesize that adiponectin might contribute to end-organ damage in hypertension.

In the present study we have evaluated the relationship between plasma adiponectin concentrations and hypertensive retinopathy. One hundred and ten patients newly diagnosed with essential hypertension (EHT) (mean age, 46.79+/-5.0 years; body mass index (BMI), 26.47+/-2.23 kg/m(2); male/female ratio, 58/52) and 57 healthy normotensive control subjects (NT) (mean age, 46.84+/-5.4 years; BMI, 26.66+/-2.65 kg/m(2); male/female ratio, 33/24) were enrolled.

Plasma adiponectin levels were significantly lower in EHT than in NT (P < 0.001). In addition, adiponectin concentrations were strongly correlated with systolic and diastolic blood pressures in EHT (r = -0.757, P < 0.001; r = -0.761, P < 0.001) while there was no correlation in the NT group. Plasma adiponectin in patients with grade 0 hypertensive retinopathy (n = 52) was significantly higher than that of the patients with grade 1 (n = 30) and 2 (n = 28) hypertensive retinopathy (P < 0.001 for each). Plasma adiponectin in patients with grade 0 hypertensive retinopathy was also significantly lower than that in the NT group (P < 0.001). The estimated threshold of plasma adiponectin concentration for hypertensive retinopathy was 17 microg/ml. This critical adiponectin level served largely to separate patients with retinopathy from those without.

Our results have shown that plasma adiponectin concentrations decrease progressively with higher grades of hypertensive retinopathy even after correction for other atherogenic risk factors, suggesting that a critical adiponectin level is needed for the development of retinopathy.