Polydeoxyribonucleotide restores blood flow in an experimental model of ischemic skin flaps

BackgroundIschemia is a major factor contributing to failure of skin flap surgery, which is routinely used for coverage of wounds to prevent infection and to restore form and function. An emerging concept is that adenosine A2A receptors can improve tissue oxygenation by stimulating angiogenesis, likely through vascular endothelial growth factor (VEGF). This study assessed the ability of polydeoxyribonucleotide (PDRN) to restore blood flow and improve wound healing, acting through the A2A receptor, in a rat model of ischemic skin flaps.MethodsThe H-shaped double-flap model was used in male Sprague-Dawley rats. After surgical procedures, the animals were randomized to receive intraperitoneal PDRN (8 mg/kg) or vehicle (NaCl 0.9%). Rats were euthanized 3, 5, and 10 days after skin injury, after the evaluation of skin perfusion by laser Doppler. The wounds underwent histologic analysis and were measured for VEGF messenger RNA and protein expression, hypoxia inducible factor-1-α (HIF-1α), and inducible nitric oxide synthase (iNOS) protein expression, and nitrite content.ResultsBlood flow markedly increased in blood flow in ischemic flaps treated with PDRN, with a complete recovery starting from day 5 (ischemic flap + vehicle, 1.80 ± 0.25; ischemic flap + PDRN, 2.46 ± 0.25; P < .001). Administration of PDRN enhanced the expression of VEGF (ischemic flap + vehicle, 5.3 ± 0.6; ischemic flap + PDRN, 6.2 ± 0.5; P < .01) at day 5, and iNOS (ischemic flap + vehicle, 3.9 ± 0.6; ischemic flap + PDRN, 5.3 ± 1; P < .01), but reduced HIF-1α expression (ischemic flap + vehicle, 7 ± 1.1; ischemic flap + PDRN, 4.8 ± 0.5; P < .05) at day 3. Histologically, the PDRN-treated group showed complete re-epithelialization and well-formed granulation tissue rich in fibroblasts.ConclusionsThese results suggest that PDRN restores blood flow and tissue architecture, probably by modulating HIF-1α and VEGF expression, and may be an effective therapeutic approach in improving healing of ischemic skin flaps.

Clinical RelevanceFuture therapies aimed at the enhancement of flap viability in vascular and reconstructive surgery, as well as to achieve a faster wound repair and angiogenesis under ischemic conditions, should include the stimulation of the adenosine A2A receptor. This report provides evidence of an agent that may have clinical use to decrease the risk of flap ischemia.