D. Michael Strong

Effect of storage and preservation methods on viability in transplantable human skin allografts

This study compared the metabolic activity of fresh skin samples to that of cadaver human skin allografts processed and stored by current tissue banking methods. We chose to use two metabolic assays as surrogate measures for viability in these grafts. Skin allografts stored either in liquid media at 4 degrees C for varying periods of time or stored by cryopreservation were quantitatively assessed for viability by tetrazolium reduction and oxygen consumption assays. These measurements were compared to viability assessments of fresh autograft skin. Human cadaver skin grafts, after procurement and just prior to further tissue bank processing, exhibited approximately 60% of the metabolic activity found in fresh skin samples obtained from living surgical donors. If allowed an overnight (18-24 h) incubation period at 37 degrees C, cadaver samples showed a recovery of their metabolic activity to 95% of that found in the autograft skin samples. When stored in liquid media at 4 degrees C, the cadaver skin declined steadily in cellular metabolic activity, arriving in less than 5 days storage at a measurement below that of cryopreserved skin. The cryopreserved skin was measured both immediately after thawing and dilution of cryoprotectant, as well as after equilibration and overnight incubation. Skin cryopreserved with dimethylsulfoxide Me(2)SO retained higher viability than glycerol cryopreserved skin. Residual concentrations of cryoprotectants were determined following typical recommendations for thawing and diluting skin allografts. The implications of these findings for transplantation and tissue banking are discussed.

Organ and tissue safety workshop 2007: advances and challenges

A workshop in June 2005 (“Preventing Organ and Tissue Allograft-Transmitted Infection: Priorities for Public Health Intervention”) identified gaps in organ and tissue safety in the US. Participants developed a series of allograft safety initiatives. “The Organ and Tissue Safety Workshop 2007: Advances and Challenges” assessed progress and identified priorities for future interventions. Awareness of the challenges of allograft-associated disease transmission has increased. The Transplantation Transmission Sentinel Network will enhance communication surrounding allograft-associated disease transmission. Other patient safety initiatives have focused on adverse event reporting and microbiologic screening technologies. Despite progress, improved recognition and prevention of donor-derived transmission events is needed. This requires systems integration across the organ and tissue transplantation communities including organ procurement organizations, eye and tissue banks, and transplant infectious disease experts. Commitment of resources and improved coordination of efforts are required to develop essential tools to enhance safety for allograft recipients.

Culture and differentiation of osteoblasts on coral scaffold from human bone marrow mesenchymal stem cells

In this paper we describe an approach that aims to provide fundamental information towards a scientific, biomechanical basis for the use of natural coral scaffolds to initiate mesenchymal stem cells into osteogenic differentiation for transplant purposes. Biomaterial, such as corals, is an osteoconductive material that can be used to home human derived stem cells for clinical regenerative purposes. In bone transplantation, the use of biomaterials may be a solution to bypass two main critical obstacles, the shortage of donor sites for autografts and the risk of rejection with allograft procedures. Bone regeneration is often needed for multiple clinical purposes for instance, in aesthetic reconstruction and regenerative procedures. Coral graft Porites lutea has been used by our team for a decade in clinical applications on over a thousand patients with different bone pathologies including spinal stenosis and mandibular reconstruction. It is well accepted that human bone marrow (hBM) is an exceptional source of mesenchymal stem cells (MSCs), which may differentiate into different cell phenotypes such as osteoblasts, chondrocytes, adipocytes, myocytes, cardiomyocytes and neurons. Isolated MSCs from human bone marrow were induced into osteoblasts using an osteogenic medium enriched with two specific growth factors, FGF9 and vitamin D2. Part of the cultured MSCs were directly transferred and seeded onto coral scaffolds (Porites Lutea) and induced to differentiate into osteoblasts and part were cultured in flasks for osteocell culture. The data support the concept that hBM is a reliable source of MSCs which may be easily differentiated into osteoblasts and seeded into coral as an optimal device for clinical application. Within this project we have also discussed the biological nature of MSCs, their potential application for clinical transplantation and the prospect of their use in gene therapy.

Coding and traceability for cells, tissues and organs for transplantation.

Modern transplantation of cells, tissues and organs has been practiced within the last century achieving both life saving and enhancing results. Associated risks have been recognized including infectious disease transmission, malignancy, immune mediated disease and graft failure. This has resulted in establishment of government regulation, professional standard setting and establishment of vigilance and surveillance systems for early detection and prevention and to improve patient safety. The increased transportation of grafts across national boundaries has made traceability difficult and sometimes impossible. Experience during the first Gulf War with miss-identification of blood units coming from multiple countries without standardized coding and labeling has led international organizations to develop standardized nomenclature and coding for blood. Following this example, cell therapy and tissue transplant practitioners have also moved to standardization of coding systems. Establishment of an international coding system has progressed rapidly and implementation for blood has demonstrated multiple advantages. WHO has held two global consultations on human cells and tissues for transplantation, which recognized the global circulation of cells and tissues and growing commercialization and the need for means of coding to identify tissues and cells used in transplantation, are essential for full traceability. There is currently a wide diversity in the identification and coding of tissue and cell products. For tissues, with a few exceptions, product terminology has not been standardized even at the national level. Progress has been made in blood and cell therapies with a slow and steady trend towards implementation of the international code ISBT 128. Across all fields, there are now 3,700 licensed facilities in 66 countries. Efforts are necessary to encourage the introduction of a standardized international coding system for donation identification numbers, such as ISBT 128, for all donated biologic products.

In vitro culture and differentiation of osteoblasts from human umbilical cord blood

It is well accepted that human umbilical cord blood (UCB) is a source of mesenchymal stem cells (MSCs) which are able to differentiate into different cell phenotypes such as osteoblasts, chondrocytes, adipocytes, myocytes, cardiomyocytes and neurons. The aim of this study was to isolate MSCs from human UCB to determine their osteogenic potential by using different kinds of osteogenic medium. Eventually, only those MSCs cultured in osteogenic media enriched with vitamin D2 and FGF9, were positive for osteocalcin by RT-PCR. All these cells were positive for alizarin red, alkaline phosphatase and Von Kossa. The results obtained from RT-PCR have confirmed that osteogenesis is complete by expression of the osteocalcin marker. In conclusion, vitamin D2, at least in vitro, may replace vitamin D3 as an osteogenic stimulator factor for MSC differentiation.

Coding and traceability for products of human origin

Abbreviations AATB American Association of Tissue Banks AETB Spanish Association of Tissue Banks BATB British Association of Tissue Banks CDC Centers for Disease Control and Prevention EATB European Association of Tissue Banks, IAEA International Atomic Energy Agency ISBT International Society of Blood Transfusion TTSN Transplantation Transmission Sentinel Network UNOS United Network for Organ Sharing WHO World Health Organization

Donor age and gender are the strongest predictors of marrow recovery from cadaveric vertebral bodies

The purpose of this retrospective analysis was to determine whether there were donor factors that were useful for predicting the yield of nucleated cells from marrow derived from cadaveric vertebral bodies. An analysis of 132 donors over a 6-year period was performed. The average number of vertebral bodies procured from each donor was 10.2 ± 1.6 (range 5–14). The total number of nucleated cells recovered per donor ranged from 24 × 109 to 160 × 109 with an average recovery of 69 ± 28 × 109 cells. The cell viability of the recovered cells was >95%. The average age of the donors was 33 ± 14 years (mean ± SD; range 12–65) with an average weight of 169 ± 41 lb (range 82–308 lb). Males comprised 68% of the donor population. The average number of days from admission to death was 1.9 ± 1.7 with a range of 1–11.4 days and the interval between asystole and procurement averaged 3.1 ± 2.3 h (range (0.1–14.7 h). The majority of donors died from head trauma due to an intracranial bleed, gunshot wound, or closed head injury. Regression analysis of the data indicated that the total nucleated cell yield tended to decrease with increasing time between hospital admission and death. The data also indicated that in general female donors yielded lower cell numbers independent of age and male donors under 30 years of age yielded the highest number of cells.

Tissue banking, biovigilance and the notify library

This issue is dedicated to the contributions of Professor Glyn O. Phillips to the field of tissue banking and the advancement of science in general. The use of ionizing radiation to sterilize medical products drew the interest of the International Atomic Energy Agency (IAEA). A meeting in 1976 in Athens Greece to present work on the effects of sterilizing radiation doses upon the antigenic properties of proteins and biologic tissues was my first introduction of Professor Phillips and the role that he was to play in Tissue Banking (Friedlaender, in Phillips GO, Tallentine AN (eds) Radiation sterilization. Irradiated tissues and their potential clinical use. The North E. Wales Institute, Clwyd, p 128, 1978). The IAEA sponsored subsequent meetings in the Republic of Korea, Czechoslovakia and Rangoon, the later including a visit to the tissue bank by Professor Phillips. His advocacy resulted in multiple workshops and teaching opportunities in a variety of countries, one of which led to the establishment of the Asia Pacific Surgical Tissue Banking Association in 1989 (Phillips and Strong, in Phillips GO, Strong DM, von Versen R, Nather A (eds) Advances in tissue banking, vol 3. World Scientific, Singapore, pp 403–417, 1999).