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Chronic wound healing by a bioengineered graft made of autologous adipose mesenchymal stem cells and allogeneic human acellular collagen matrix

Aurore Lafosse², Marie-Sophie Hanet¹, Najima Aouassar¹, Daela Xhema¹, Rose-Marie Goebbels¹, Romain Vanwijck², Denis Dufrane¹

¹Endocrine Cell Therapy; ²Plastic Surgery Service, University Clinical Hospital Saint-Luc/UCL, Brussels, Belgium

Background: Chronic wounds are difficult to heal. This work investigated the potential of a bioengineered graft made of autologous Adipose Mesenchymal Stem Cells (AMSCs) and allogeneic Human Acellular Collagen Matrix (HACM) to improve angiogenesis and dermal reconstruction.

Methods: Two patients developed untreatable chronic ulcerations consequently to (patient 1) a radiotherapy (50 Grays) as adjuvant therapy of a malignant sarcoma (one lesion of 12cm², proximal left tibia) and (patient 2) drepanocytosis (two bimalleolar hyperalgic ulcers of 95/127cm²). After one year of ulceration course, repeatitive unsuccessful skin grafts, infections and hospitalizations, autologous AMSCs were isolated by cGMP-collagenase digestion and proliferated up to Passage 4 ^th before loading on the HACM. AMSCs (CD90 expression) were characterized by the capacity of osteogenic (Alizarin Red/Osteocalcin/VonKossa staining)/adipogenic (Oil red staining) differentiation and angiogenic properties (in vitro VEGF release at 0.1/5/21% Oxygen). Bioengineered grafts were implanted when the total HACM was colonized by AMSCs and were followed by inflammatory reaction (White blood cells/CRP/fibrinogen levels) and tissue reconstruction (CD3/CD68/Melanocyte/Proteoglycan and Mart-1 staining for lymphocytes/macrophages/ epithelialization, respectively).

Results: Prior tranplant, chronical ulcerations demonstrated a strong fibrotic tissue with a low vascular density. The composite graft was macroscopically incorporated into the scaring tissue at day 3 and completely integrated after 28 days post-implantation. Histological examination demonstrated a significant higher expression of VEGF, angiogenesis (a capillar density over 600/mm², p<0.005) in the wound without any significant infiltration by CD3/CD68 cells. A skin-like tissue with a complete re-epithelialization and considerable glandular structure formation was also found for Patient 1. For patient 2, a superficial skin graft was secondly implanted (after 6 weeks post-AMSCs transplantation) and induced a complete wound healing without any wound recurrence at 4 months post-transplantation and complete pain relief.

Conclusions: This bioengineered graft made of autologous AMSCs potentiates angiogenesis and skin reconstruction to cure fibrotic area of chronical wound.