APPLICAZIONE SPERIMENTALE DI VASI UMANI DECELLULARIZZATI DI PICCOLO CALIBRO

Tissue engineering mean a wide field of science application in searching the substitusion by different process of damaged human tissue. The main intent is to obtain scaffold that can perfectly mimic the structural and functional characteristics of damaged tissues or organs. In the field of vascular graft numerous studies were conducted to obtain suitable tissue that could supplant the use of autologous bypassor even the littlest vessel employed in microsurgery. Over the years, various solutions have been proposed. The use of resorbable or non-resorbable vascular synthetic conduits, associated or not to stem cells and growth factors, small-caliber decellularized vessels and scaffold-free methods have been described in the literature. First, our study has produced experimental animal models in which a section of the rabbit femoral vessels was replaced by small caliber (inner diameter < 6 mm) human decellularized vessel. Materials and methods Two arteries and two human veins of small caliber (< 6 mm) obtained by upper arm lesions not suitable for surgical procedure were withdrawn and subjected to a process of decellularization according to a modified Sheridan’s protocol. The effectiveness of the process was shown in vitro with histological, immunohistochemical, ultrastructural, and qualitative and quantitative analysis of DNA. Mechanical testing and functional ecodoppler in vivo were also performed. Decellularized vessels were implanted in vivo in rabbit femoral vessels. The patency was verified, in vivo, at time 0, 10 and 20 minutes later. After 30 days for vein implants and 10 and 40 days for artery implants, the rabbits were sacrificed. The patency of grafts, the inflammatory process and re-endothelialization was tested with histological and immunophenotypical analysis. At the same time we analyzed also synthetic vessel as control , after two weeks of implantation. Results The various assays of decellularized vessels, in vitro, demonstrated the success of the process. The cellular component was eliminated without altering the composition and three-dimensional structure of extra cellular matrix. It was also confirmed by mechanical testing. The scaffolds were implanted successfully in all models and the patency was maintained until animals’ sacrifice, as also documented by ecocolordoppler evaluation. The histological and immunophenotypical analysis of taken scaffolds showed a minimal inflammatory process, the maintenance of the extracellular matrix structure and the wall and luminal surface re-cellularization. The syntethic vessel demonstrate complete thrombosis. Conclusions The adjustments made to the decellularization protocol proposed by Sheridan helped to keep acceptable length of the process maintaining the same effectiveness. Non-use of endothelial stem cells reduced costs even if, for longer grafts the use of cells to improve biocompatibility seems to be necessary. The histological studies on withdrawn grafts have demonstrated a minimal presence of inflammatory processes, a complete patent in two weeks till eight weeks and the presence of a process of re-cellularization. The excellent biocompatibility of implanted scaffolds suggest the possibility of a subsequent application in clinical microvascular field and, in the future, for the establishment of a tissue bank to find substitutes with suitable caliber and length. Additional animal testing, with long time survival, mechanical and histological analysis are definitely essential to determine the effectiveness of these implants and think of a possible clinical trials

Management and Clinical Aspects of Burned Patients Affected by SARS-COV2

At the end of January 2020, SARS-CoV-2 started escalating worldwide. COVID-19 can exert its effects on immunity, inflammation, and multi-organ system disease, common denominators with the burn injury. The pandemic required major efforts to Burn centres in order to preserve burn patients’ care and contribute to the health care response. In our Burn Unit we autonomously developed a protocol for patients acceptance and surveillance of the hospitalized ones and the personnel. We briefly describe our experience with six cases of burn patients infected by SARS-CoV-2 highlighting the overlap between medical treatment of burn patients and COVID-19 patients. To avoid viral spreading epidemiologic control is essential, especially preventive measures such as isolation of infected patients and identification of the source of infection. In our surgical practice, we increased the use of enzymatic debridement avoiding procedures with a high risk of viral particles spreading. Personnel protection and dedicated pathways have been planned, optimizing air circulation and disinfection. Vaccines represent the best hope for the global population to stop the viral spread, despite new variants outbreaks

Comparison of reasorbeable mini anchor versus non reasorbeable: histological evaluation in an experimental rabbit mode

Purpose. Experimental animal study to evaluate the osseo integration, inflammatory response, dislocation and the reabsorption timing of the reasorbeable Mitek® mini anchor, in comparison with the non reasorbeable titanium based. Methods. Twenty rabbits were used: divided into two groups of ten. Each animal underwent sectioning and reinsertion of the Achilles tendon bilaterally, using a reasorbeable mini anchor on one side and a controlateral non reasorbeable mini anchor. The first group was sacrificed after 40 days and the other after 120 days. The bone tendon complex was subjected to histological study. Results. No histological and statistical significative difference were observed in each group, with a lower inflammation response in the reasorbeable implant. Electronic microscopy evaluation demonstrates good stability of the implant in each group. At day 120 the reasorbeable anchors were not yet disappeared. Conclusion. Reasorbeable Mitek mini anchors are to be considered to guarantee a similar response and similar bone stability than non reasorbeable ones