Changes in skin blood flow in type 2 diabetes induced by prostacyclin: Association with ankle brachial index and plasma thrombomodulin levels

Abstract

In a previous study, we reported that beraprost sodium (BPS), a stable prostaglandin I2 (PGI2) analog, increases skin blood flow in the feet of both control subjects and patients with type 2 diabetes, and that the flow increase induced by BPS is lower in diabetic patients than in controls. The present study was undertaken to clarify factors associated with smaller increases in skin blood flow in the feet of patients with type 2 diabetes after the administration of BPS, and to investigate the relationship between microalbuminuria and the changes in skin blood flow induced by the PGI2 analog. We studied 61 patients with type 2 diabetes: 10 received placebo (control) and 51 (31 with normoalbuminuria and 20 with microalbuminuria) received BPS. Using laser Doppler flowmetry, we measured the skin blood flow at the pulp of the right big toe before and 90 minutes after administration of 40 μg BPS, and calculated the change in blood flow, ie, delta flux (peak flux at 90 minutes − basal flux at 0 minutes). Plasma concentrations of soluble thrombomodulin (TM) were determined using an enzyme immunoassay (EIA) sandwich method. BPS significantly increased skin blood flow in the treatment group compared with the placebo group (P < .01). The delta flux was positively correlated with the value of the ankle brachial index (ABI) (r = .41, P < .0038) and was negatively correlated with plasma TM levels (r = −.53, P < .0001). By multiple regression analysis both the ABI value and the plasma TM level retained a significant influence on delta flux. Furthermore, both the delta flux and the ABI value in patients with microalbuminuria were lower than in patients with normoalbuminuria (P < .05). The results suggest that BPS increases the skin blood flow of the toe of patients with type 2 diabetes and that the increased flow is independently influenced by the value of the ABI and the plasma TM levels; in addition, microalbuminuria is associated with the impairment of vasodilation in the feet in response to BPS.