Cutaneous iontophoresis of treprostinil, a prostacyclin analog, increases microvascular blood flux in diabetic malleolus area

Diabetic foot ulcers are one of the most common and serious complications of diabetes mellitus. Few drugs are effective in enhancing the healing of microvascular skin ulcers. The main objective of the present study was to determine whether iontophoresis of treprostinil, a prostacyclin analog, increases skin microvascular blood flux in the malleolus area of healthy subjects and diabetic patients. We recruited 12 healthy subjects and 12 type 2 diabetic patients. Cathodal iontophoresis (40 mC/cm²) of treprostinil 250 µM and NaCl 0.9% was performed in the malleolus area. Skin hyperemia was quantified using non-invasive laser speckle contrast imaging, and expressed as the area under the curve (AUC) of cutaneous vascular conductance (CVC). In healthy controls and diabetic patients, treprostinil 250 µM induced a significant increase in CVC compared with NaCl (for diabetic patients, AUC0-6 h was 19970±8697; versus 2893±5481%BL.min, respectively; P=0.002). In both groups, the peak flux was obtained between 30 min and 1 h after the end of treprostinil iontophoresis and flux remained higher than baseline up to 6 h after ending of iontophoresis. No significant side-effect occurred. Cutaneous iontophoresis of 250 µM treprostinil increases microvascular blood flux in the malleolus area in healthy volunteers and diabetic patients, without inducing systemic or local side-effects. Treprostinil cathodal iontophoresis should be further investigated as a new local therapy for diabetic ulcers.