Expression of cell proliferation cycle negative regulators in fibroblasts of an ischemic diabetic foot ulcer. A clinical case report.

Wound chronification and opportunistic infections stand as major factors leading to lower extremities amputations in diabetes. The molecular mechanisms underlying diabetic's torpid healing have not been elucidated. We present the case of a female diabetic patient that after a plantar abscess surgical drainage, tight glycaemia control and infection clearance; the wound bed evolved to chronification with poor matrix accumulation, scant angiogenesis and no evidence of dermo-epidermal contours contraction. Ulcer fibroblasts yet cultured under 'physiological' conditions exhibited a slow and declining proliferative response. Diabetic fibroblasts cycle arrest occurred earlier than non-diabetic counterparts. This in vitro premature arrest-senescence phenotype appeared related to the transcriptional upregulation of p53 and the proto-oncogene c-myc; with a concomitant expression reduction of the survival and cellular growth promoters Akt and mTOR. Importantly, immunocytochemistry of the diabetic ulcer-derived fibroblasts proved nuclear over expression of potent proliferation inhibitors and pro-senescence proteins as p53 phosphorylated on serine-15 and p21(Cip) (1). In line with this, cyclin D1 appeared substantially underexpressed in these cells. We postulate that the downregulation of the Akt/mTOR/cyclin D1 axis by the proximal activation of p53 and p21 due to stressor factors, impose an arrest/pro-senescence programme that translated in a torpid and slow healing process.

Intramyocardial gene transfer of vascular endothelial growth factor 121 improves myocardial perfusion and function in the ischemic porcine heart

Vascular endothelial growth factor (VEGF) is an endothelial cell-specific mitogen that is angiogenic in vitro and in vivo. Several studies report on gene transfer of VEGF121 to promote angiogenesis in the ischemic myocardium of animals and patients. We hypothesized that intramyocardial administration of naked plasmid DNA encoding VEGF121 could improve myocardial perfusion and function in a porcine model of myocardial ischemia. Yorkshire swine underwent thoracotomy and placement of an ameroid constrictor on the circumflex coronary artery. Four weeks later, pVEGF121 plasmid was administered into the ischemic myocardium. Four weeks after gene transfer, SPECT imaging demonstrated significant reduction in the ischemic area in pVEGF121-treated animals compared with controls. In the pVEGF121 group, most of the animals evolved from light ischemia to a normal perfusion. In contrast, control animals exhibited similar or impaired ischemic conditions. Our results indicate that intramyocardial gene transfer of VEGF121 as naked plasmid DNA results in significant improvement in myocardial perfusion and function.