Noninvasive induction of angiogenesis in tissues by external suction: sequential optimization for use in reconstructive surgery.

In reconstructive surgery, tissues are routinely transferred to repair a defect caused by trauma, cancer, chronic diseases, or congenital malformations; surgical transfer intrinsically impairs metabolic supply to tissues placing a risk of ischemia-related complications such as necrosis, impaired healing, or infection. Pre-surgical induction of angiogenesis in tissues (preconditioning) can limit postsurgical ischemic complications and improve outcomes, but very few preconditioning strategies have successfully been translated to clinical practice due to the invasiveness of most proposed approaches, their suboptimal effects, and their challenging regulatory approval. We optimized a method that adopts noninvasive external suction to precondition tissues through the induction of hypoxia-mediated angiogenesis. Using a sequential approach in a rodent model, we determined the parameters of application (frequency, suction levels, duration, and interfaces) that fine-tune the balance of enhanced angiogenesis, attenuation of hypoxic tissue damage, and length of treatment. The optimized repeated short-intermittent applications of intermediate suction induced a 1.7-fold increase in tissue vascular density after only 5 days of treatment (p < 0.05); foam interfaces showed the same effectiveness and caused less complications. In a second separate experiment, our model showed that the optimized technique significantly improves survival of transferred tissues. Here we demonstrate that noninvasive external suction can successfully, safely, and promptly enhance vascularity of soft tissues: these translational principles can help design effective preconditioning strategies, transform best clinical practice in surgery, and improve patient outcomes.

Decellularized omentum as novel biologic scaffold for reconstructive surgery and regenerative medicine.

Homologous tissues, such as adipose tissue, may be an interesting source of acellular scaffolds, maintaining a complex physiological three-dimensional (3D) structure, to be recellularized with autologous cells. The aim of the present work is to evaluate the possibility of obtaining homologous acellular scaffolds from decellularization of the omentum, which is known to have a complex vascular network. Adult rat and human omenta were treated with an adapted decellularization protocol involving mechanical rupture (freeze-thaw cycles), enzymatic digestion (trypsin, lipase, deoxyribonuclease, ribonuclease) and lipid extraction (2-propanol). Histological staining confirmed the effectiveness of decellularization, resulting in cell-free scaffolds with no residual cells in the matrix. The complex 3D networks of collagen (azan-Mallory), elastic fibers (Van Gieson), reticular fibers and glycosaminoglycans (PAS) were maintained, whereas Oil Red and Sudan stains showed the loss of lipids in the decellularized tissue. The vascular structures in the tissue were still visible, with preservation of collagen and elastic wall components and loss of endothelial (anti-CD31 and -CD34 immunohistochemistry) and smooth muscle (anti-alpha smooth muscle actin) cells. Fat-rich and well vascularized omental tissue may be decellularized to obtain complex 3D scaffolds preserving tissue architecture potentially suitable for recellularization. Further analyses are necessary to verify the possibility of recolonization of the scaffold by adipose-derived stem cells in vitro and then in vivo after re-implantation, as already known for homologus implants in regenerative processes.

Burn care in relation to burn epidemiology in Italy.

AIM: Burn centres are 'hubs' of referral for large areas and should be organised in a network optimised for the needs of their area. Burn centres' organisation and activity in Italy are analysed with reference to burn epidemiology in the country. METHODS: A questionnaire was submitted to Italian burn centres concerning organisation, activity and epidemiology of burns treated in 2008. RESULTS: A total of 2067 patients were admitted to a burn centre in 2008; 50% of burns were due to flames (21% alcohol); and 25% of patients were <14 years old. Overall mortality was 5.3%. 144 beds in 15 burn centres were available (seven reserved for children; bed/inhabitants ratio, 1/414, .023). However, distribution is not uniform in the country. Bed rotation was 14.4 patients/bed, and hospital stay varied from 11.7 days for <20% total body surface area (TBSA) burns to >120 days for burns >70%. About half (57%) of patients admitted had less than 20% TBSA burns, 32% had 20-50% TBSA burns, 7% from 50% to 70% and 4% over 70% TBSA. A national network coordinating burn centre activity is lacking. CONCLUSIONS: Italy seems to have less availability of beds for burn care than other countries, and distribution and organisation of the network may be improved. The high prevalence of child burns should be noticed and this makes prevention campaigns advisable.