Synthesis and characterization of a bovine collagen: GAG scaffold with Uruguayan raw material for tissue engineering.

Tissue engineering (TE) and regenerative medicine offer strategies to improve damaged tissues by using scaffolds and cells. The use of collagen-based biomaterials in the field of TE has been intensively growing over the past decades. Mesenchymal stromal cells (MSCs) and dental pulp stem cells (DPSCs) are promising cell candidates for development of clinical composites. In this study, we proposed the development of a bovine collagen type I: chondroitin-6-sulphate (CG) scaffold, obtained from Uruguayan raw material (certified as free bovine spongiform encephalopathy), with CG crosslinking enhancement using different gamma radiation doses. Structural, biomechanical and chemical characteristics of the scaffolds were assessed by Scanning Electron Microscopy, axial tensile tests, FT-IR and Raman Spectroscopy, respectively. Once we selected the most appropriate scaffold for future use as a TE product, we studied the behavior of MSCs and DPSCs cultured on the scaffold by cytotoxicity, proliferation and differentiation assays. Among the diverse porous scaffolds obtained, the one with the most adequate properties was the one exposed to 15 kGy of gamma radiation. This radiation dose contributed to the crosslinking of molecules, to the formation of new bonds and/or to the reorganization of the collagen fibers. The selected scaffold was non-cytotoxic for the tested cells and a suitable substrate for cell proliferation. Furthermore, the scaffold allowed MSCs differentiation to osteogenic, chondrogenic, and adipogenic lineages. Thus, this work shows a promising approach to the synthesis of a collagen-scaffold suitable for TE.

Quality management indicators for tissue banks: an operative model from the period of 2002-2007.

AIM: The purpose of this study was to determine a specific indicator model to evaluate the Quality Management System (QMS) in Tissue Banks (TB) for deceased and/or live donors. METHODS: Quantitative Indicators for Quality Management are considered for deceased donors as the origin of therapeutic tissues. A glossary of definitions was established (also applicable for tissues from live donors): Deceased Therapeutic Real Donors (DTRD), donors that were processed and at least 1 tissue was harvested for a therapeutic purpose; Deceased Effective Donors (DED), DTRD in which 1 or more tissues were validated, stored, and/or grafted; Processed Tissues (PT), number of tissues harvested from a DTRD, which were processed and counted as final product units; Validated Tissues (VT), number of tissues as final product units, which fulfilled quality criteria to be grafted; Grafted Tissues (GT), number of transplanted tissues for therapeutic purposes; and Grafted Patients (GP), number of patients who were grafted with validated tissues. MANAGEMENT QUANTITATIVE INDICATORS: Deceased donors were considered from 2002 to 2007. The total number of tissues was 15,363: Productivity Index (PI), PI = DED/DTRD; Processing Quality Rate (PQR), PQR = VT/PT%; Productivity Efficiency per Donor (PED), PED = VT/DED; Grafted Tissues Coefficient (GTC), GTC = GT/VT; and Grafted Patients Index per Donor (GID), GID = GP/DED. RESULTS: Results were as follows: PI = 0.80; PQR = 76%; PED = 30.99; GTC = 0.93; and GID = 4. In our study, 80% of DTRD produced VT (PI = 0.80), which represented 76% of PT (average, 31 final products per donor). Also, 93% of the VT were grafted with 5 patients grafted per donor. CONCLUSIONS: Defined variables resulted in useful tools to evaluate QMS in a TB.

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Uruguay: development of tissues quality control and quality management system in the National Multi-Tissue Bank of Uruguay.

BNOT was created and regulated in 1977 and started its operation in 1978 according to the Decree No. 86/1977. By the Decree 248/005 is transformed in the National Institute of Donation and Transplantation of Cells, Tissues and Organs (Instituto Nacional de Donación y Trasplante de Células, Tejidos y Organos--INDT). The organisation has been operating within the State University Medical School and the Public Health Secretary and it is the governmental organisation responsible for the regulation, policy and management of donation and transplantation in Uruguay. By the Decree 160/2006 is responsible for human cells and tissues regulation too. The participation of the INDT in the IAEA program facilitated the introduction of the radiation sterilisation technique for the first time in the country. The radiation sterilisation of tissues processed by INDT (ex BNOT), was initially carried out in the 60 Cobalt Industrial Plant in the National Atomic Energy Commission of Argentina and now is carried out in INDT, using a Gamma Cell 220 Excel, which was provided by the IAEA through the national project URU/7/005. The results of the implementation of tissues, quality control and quality management system, are showed.

Control of cryopreservation procedures on blood vessels using fiber x-ray diffraction.

AIM: We sought to determine variations in fiber organization at the molecular level using x-ray diffraction analyses on human blood vessel specimens after cryopreservation processes. MATERIALS AND METHODS: Diffractometric profiles were performed on aortic and carotid cryopreserved-thawed vessel samples (CVS) versus the same fresh vessel samples (FVS). X-ray diffraction was performed on vascular tissues from 17 cadaveric donors after informed consent. Measurements utilized a Seifert Scintag PAD-II powder diffractometer with CuK(a) radiation; lambda = 1.5418 A. Scans were evaluated in the 5 degrees to 60 degrees range in theta -2theta mode, in the 5 degrees to 60 degrees range in 2-theta, with steps 0.1 degrees and 10 seconds per step. Ten aortic and 8 carotid diffractometric profiles were analyzed, using differential planimetric surfaces measured under x-ray diffraction curve. Diffractographic profiles were analyzed according to intervals based upon the ages of the donors. An ordering profile coefficient (OPC) was obtained as the quotient between the differential planimetric surface (DPS) of FVS versus CVS vessel ordering diffraction. RESULTS: There was a decreased ordering profile according to age: older donors showed less ordering than younger ones. Clear peaks at d-spacing of 2.86 A and 2.15 A (2-theta = 31.3 degrees and 42.0 degrees , respectively) were always confirmed despite the different profiles of samples. OPC showed a higher ordering profile among the CVS than FVS: 70% aortas and 62.5% carotids. CONCLUSION: The cryopreserved-thawed procedure does not damage the fibrillar organization of vessels.

Dynamics of cryopreserved human carotid arteries.

The viscoelastic properties of the arterial wall are responsible for their functional role in the arterial system. Cryopreservation is widely used to preserve blood vessels for vascular reconstruction but is controversially suspected to affect the dynamic behaviour of these allografts. The aim of this study was to determine whether differences in the dynamic behaviour exist or not between fresh and cryopreserved human common carotid arteries (CCA). Using a previously developed mock circulation system, dynamic pressure-diameter tests were performed on segments of human fresh (n=10) and cryopreserved arteries (n=7). A diameter-pressure transfer function was designed to evaluate the wall dynamics. An adaptive model was fit to obtain its frequency response. Three models were tested. Results show that non-significant differences exist between wall dynamics of fresh and cryopreserved segments of human CCA.

[The importance of HLA antigens in alcoholic cirrhosis]. / HLA y cirrosis. La importancia de los antígenos de histocompatibilidad en el desarrollo de una cirrosis alcoholica.

The existence of a relationship between HLA and the possibility of the development of an alcoholic cirrhosis is researched in this paper. This work was done from 1982 to 1984, by the staff of four clinics of the Medicine School of the University of Uruguay. We studied 47 alcoholics with portal cirrhosis, 19 non-cirrhotic alcoholics and 250 healthy nonalcoholic controls. We confirmed with liver biopsy the cirrhosis in the first group and in the second, liver biopsy was performed in order to assure that they had no cirrhosis. Table I shows the histocompatibility antigens which were tested in the 3 groups. Levels of significance were obtained from exact Fisher test with Yates correction for discontinuity; Pc (corrected P) and RR (relative risk) were also determined. In the alcoholics with portal cirrhosis, the HLABW40 showed a Pc less than 0,005 (RR = 3,93). In the non-cirrhotic alcoholics no significative association was found. We conclude that the carrier of the genetic marker HLABW40, has almost 4 times more chances to develop a cirrhosis as consequence of chronic alcoholic abuse. The presence of this marker, in our patients, has no association with the possibility that an individual becomes an alcoholic abuser. We think that if this data are confirmed in a wider study, some guidelines for the prevention of alcoholic cirrhosis may be established.

HLA y cirrosis. La importancia de los antígenos de histocompatibilidad en el desarrollo de una cirrosis alcoholica. / [The importance of HLA antigens in alcoholic cirrhosis]

The existence of a relationship between HLA and the possibility of the development of an alcoholic cirrhosis is researched in this paper. This work was done from 1982 to 1984, by the staff of four clinics of the Medicine School of the University of Uruguay. We studied 47 alcoholics with portal cirrhosis, 19 non-cirrhotic alcoholics and 250 healthy nonalcoholic controls. We confirmed with liver biopsy the cirrhosis in the first group and in the second, liver biopsy was performed in order to assure that they had no cirrhosis. Table I shows the histocompatibility antigens which were tested in the 3 groups. Levels of significance were obtained from exact Fisher test with Yates correction for discontinuity; Pc (corrected P) and RR (relative risk) were also determined. In the alcoholics with portal cirrhosis, the HLABW40 showed a Pc less than 0,005 (RR = 3,93). In the non-cirrhotic alcoholics no significative association was found. We conclude that the carrier of the genetic marker HLABW40, has almost 4 times more chances to develop a cirrhosis as consequence of chronic alcoholic abuse. The presence of this marker, in our patients, has no association with the possibility that an individual becomes an alcoholic abuser. We think that if this data are confirmed in a wider study, some guidelines for the prevention of alcoholic cirrhosis may be established.