Tissue Characterization after a New Disaggregation Method for Skin Micro-Grafts Generation

Several new methods have been developed in the field of biotechnology to obtain autologous cellular suspensions during surgery, in order to provide one ...

Burns Centre and Emilia Romagna Regional Skin Bank

The high incidence of recurrent tendon tears after repair of massive cuff lesions is prompting the research of materials aimed at mechanically or biologically reinforcing the tendon. Among the materials studied upto now, the extracellular matrix (ECM) scaffolds of human origin have proved to be the safest and most efficient, but the current laws about grafts and transplants preclude their use in Europe. In order to overcome this condition in 2006, we started a project regarding the production of an ECM scaffold of human origin which could be implanted in Europe too. In 2009, the clinical study began with the implantation of dermal matrix scaffolds in 7 middle-aged patients affected with large/massive cuff lesions and tendon degeneration. Out of 5 cases, followed for at least 1 year in which the scaffold was employed as an augmentation device, there were 3 patients with complete healing, 1 partial re-tear, and 1 total recurrence. The absence of adverse inflammatory or septic complications allows to continue this line of research with a prospective controlled study in order to define the real advantages and correct indications offered by scaffold application.

Human dermal matrix scaffold augmentation for large and massive rotator cuff repairs: preliminary clinical and MRI results at 1-year follow-up.

Interest is increasing in biological scaffolds for tissue regeneration such as extracellular matrix membranes, developed through soft tissue decellularization. Extracellular matrix membranes were developed to heal different tendon and soft tissue lesions that are very frequent in the general population with high health-care costs and patient morbidity. The aim of this research was to evaluate a human dermal matrix (HDM) decellularized by a chemico-physical method. A primary culture of rat tenocytes was performed: tenocytes were seeded on HDM samples and on polystyrene wells as controls (CTR). Cell viability and synthetic activity were evaluated at 3 and 7 days. An in vitro microwound model was used to evaluate HDM bioactivity: after tenocyte expansion, artificial wounds were created, HDM extracts were added, and closure time and decorin synthesis were monitored histomorphometrically at 1, 4, 24, and 72 hr. A significant higher amount of collagen I was observed when cells were cultured on HDM in comparison with that on CTR (3 days: p < 0.0001; 7 days: p < 0.05). In HDM group, fibronectin synthesis was significantly higher at both experimental times (p < 0.0001). At 3 days, proteoglycans and transforming growth factor-β1 releases were significantly higher on HDM (p < 0.0001 and p < 0.005, respectively). The artificial microwound closure time and decorin expression were significantly enhanced by the addition of 50% HDM extract (p < 0.05). In vitro data showed that the decellularization technique enabled the development of a matrix with adequate biological and biomechanical properties.

Decellularized human dermis to treat massive rotator cuff tears: in vitro evaluations.

Interest is increasing in biological scaffolds for tissue regeneration, such as extracellular matrix (ECM) membranes, developed through soft tissue decellularization. The present study describes the development of a chemicophysical decellularization method applied to allogenic human-derived dermis (HDM). To evaluate the absence of viable cells and the maintenance of ECM structure, biological, histological and ultrastructural assessments were performed on the HDM membrane. Residual DNA content and glycosaminoglycan (GAG) and collagen contents were quantified. Growth factor (GF) release was directly measured on HDM extracts and indirectly measured by assessing cell proliferation after administering extract to cultures. Tensile tests were performed to measure the effect of the decellularization technique on the mechanical properties of tissue. Histocompatibility was investigated after subcutaneous implantation in rats. Residual DNA, GAG and collagen content measurements, vitality index, histology and electron microscopy showed the efficiency of the decellularization process and preservation of ECM matrix and bioactivity. In HDM extracts, among the tested GFs, transforming growth factor-β1 showed the highest concentration. HDM extracts significantly increased the proliferation rate of L929 fibroblasts in comparison with controls (p < 0.005, p < 0.05 and p < 0.0005). Maximum load and stiffness of HDM were significantly higher than those of cellularized dermis (p < 0.0005, p < 0.005). Histological and histomorphometric analysis of explanted samples showed that the membrane was integrated with host tissues in the absence of inflammatory reactions. Our results show that the decellularization method allowed the development of a human allograft dermal matrix that might be useful for soft tissue regeneration.

Development and evaluation of a decellularized membrane from human dermis.

Although progress has been made in the treatment of articular cartilage lesions, they are still a major challenge because current techniques do not provide satisfactory long-term outcomes. Tissue engineering and the use of functional biomaterials might be an alternative regenerative strategy and fulfill clinical needs. Decellularized extracellular matrices have generated interest as functional biologic scaffolds, but there are few studies on cartilage regeneration. The aim of this study was to evaluate in vitro the biological influence of a newly developed decellularized human dermal extracellular matrix on two human primary cultures.

Elena Bondioli

Burns Centre and Emilia Romagna Regional Skin Bank

Tissue Characterization after a New Disaggregation Method for Skin Micro-Grafts Generation