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.