Polydeoxyribonucleotide (PDRN): a safe approach to induce therapeutic angiogenesis in peripheral artery occlusive disease and in diabetic foot ulcers.

Peripheral arterial occlusive disease (PAOD) of lower extremities is becoming more prevalent worldwide. The general prognosis is particularly negative with a high prevalence of coronary heart disease and cerebrovascular disease. Diabetic foot ulcers occur in 15% of all the patients with diabetes and proceed to lower-leg amputations. In diabetic ulcers, wound healing is impaired because of delayed angiogenesis. In both pathological conditions, therapeutic angiogenesis using angiogenic growth factors, particularly Vascular Endothelial Growth Factor VEGF, is expected to be a valuable treatment. The most used approaches are based on VEGF local delivery or gene therapy, but they failed to meet the expected primary goals of therapy. Adenosine receptor stimulation can induce VEGF expression in many types of cells and this may be achieved by stimulating the A(2A) or A(2B) receptor or both, following the signalling pathways activated by hypoxia. Polideoxyribonucleotide (PDRN) is obtained from sperm trout by an extraction process. The compounds hold a mixture of deoxyribonucleotides polymers with chain lengths ranging between 50 and 2000 bp. PDRN is able to stimulate VEGF production during pathological conditions of low tissue perfusion. It likely acts through the stimulation of A(2A) receptors. Furthermore, acute and chronic toxicity studies showed a good safety profile. PDRN has been shown to be effective in an experimental model of PAOD, hind limb ischemia, impaired wound healing and burn injury. Preliminary studies and ongoing clinical trials predict a significant therapeutic efficacy in patients. These data lead to hypothesize a role for PDRN in therapeutic angiogenesis.

Polydeoxyribonucleotide (PDRN) promotes human osteoblast proliferation: a new proposal for bone tissue repair.

Several researchers have recently shed new light upon the importance of extracellular nucleotides and nucleosides to stimulate cells growth. PDRN, a mixture of deoxyribonucleotides polymers of different lengths, has recently demonstrated to stimulate "in vitro" fibroblast proliferation and collagen production, probably stimulating the purinergic receptor system. In this work we evaluated the effects of PDRN on human cultured osteoblasts, focusing our attention on cell proliferation and alkaline phosphatase activity. PDRN at a concentration of 100 microg/ml induce an increase in osteoblasts growth after 6 days as compared to control (+21%). The addition of DMPX 50 microM and suramine (P2 inhibitor) 10 microM give different results: suramine has no significant effect, while DPMX reduce, even if partially, the PDRN induced cell growth. The alkaline phosphatase activity shows a gradual enhancement starting from day 0 to day 10, even if PDRN treated cells, examined at day 6, present a sensibly lower phosphatase activity when compared to controls. Our data demonstrate that PDRN acts as an osteoblast growth stimulator. Its action is partially due to a stimulation of the purinergic system mediated by A2 purinoreceptors, however we can not exclude the involvement of other mechanism like salvage pathway.