ARGUMENTS AGAINST PROMOTING ORGAN TRANSPLANTS FROM BRAIN‐DEAD DONORS,AND VIEWS OF CONTEMPORARY JAPANESE ON LIFE AND DEATH

As of 2009, the number of donors in Japan is the lowest among developed countries. On July 13, 2009, Japan's Organ Transplant Law was revised for the first time in 12 years. The revised and old laws differ greatly on four primary points: the definition of death, age requirements for donors, requirements for brain‐death determination and organ extraction, and the appropriateness of priority transplants for relatives. In the four months of deliberations in the National Diet before the new law was established, various arguments regarding brain death and organ transplantation were offered. An amazing variety of opinions continue to be offered, even after more than 40 years have elapsed since the first heart organ transplant in Japan. Some are of the opinion that with the passage of the revised law, Japan will finally become capable of performing transplants according to global standards. Contrarily, there are assertions that organ transplants from brain‐dead donors are unacceptable because they result in organs being taken from living human beings. Considering the current conditions, we will organize and introduce the arguments for and against organ transplants from brain‐dead donors in contemporary Japan. Subsequently, we will discuss the primary arguments against organ transplants from brain‐dead donors from the perspective of contemporary Japanese views on life and death. After introducing the recent view that brain death should not be regarded as equivalent to the death of a human being, we would like to probe the deeply‐rooted views on life and death upon which it is based.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Mexico

Tissue banking started in Mexico in 1948-1949, when two bone banks were established, one at the Infantile Hospital of Mexico and other at the Central Military Hospital. Mexico has benefited for the implementation of the IAEA program since through it has been able to settle down and to consolidate the Tissue Bank at the Instituto Nacional de Investigaciones Nucleares ININ (National Institute for Nuclear Research). This is the only bank in Latin America that has a Quality Management System in force, certified under ISO 9001:2000 since August 1, 2003. The first tissue processed was amnion. The main products of the BTR are amnion and pig skin. Both are biological tissues which their main use is as a wound dressing in patients with burns, scars, diabetic ulcers, epidermolysis bullosa, damaged ocular surface, etc. The General Health Law, published in 1984 and reformed in June 19, 2007, describes the procedure for the disposal of organs, tissues and human cadavers in its fourteenth title and in the Regulation for Sanitary Control. During the period 2001-2005, the ININ Tissue Bank produced 292 sterilised tissues (amnion, 86,668 cm², and frozen pig skin, 164,220 cm², at an estimated cost of 1,012,668 Mexican pesos. Until 2006, one hundred eighty five (185) patients have been treated with the use of sterilised tissues produced by the ININ Tissue Bank. The radiation source used for sterilisation of tissues is an industrial Cobalt-60 irradiator model JS-6500 AECL, which belongs to ININ. This equipment is located in other building, close to the BTR, in the Centro Nuclear de México “Dr. Nabor Carrillo Flores” (Nuclear Center of Mexico). Until 2006, six hospitals use in a routine way the sterilised tissues produced by the ININ Tissue Bank, for the treatment of burns originated by diverse agents like flame, electricity, liquids in boil, chemical reagents, as well as for the reconstruction of the ocular surface. Two of these hospitals treat patients of very low economic incomes, mainly needy individuals, who cannot afford to pay this type of treatments in other hospitals due to their high cost. The results obtained up to now are highly promising.     

Tissue banking in Mexico

Introduction: Here, we describe our Tissue Banking experiences of 4 years of activity in Mexico. Methods: Data of allografts provided by our Bank and bone retrievals performed by our teams between February of 2001 and August of 2004 were included. Results: There were 100 bone donors, a total of 1107 tissues were obtained with an average of 11 tissues by retrieval, samples from all tissues were obtained during retrieval and cultured for bacterial contamination, 250 tissues were positives to bacterial growth with an average of 22.58% of bacterial contamination of tissue by retrieval. A total of 4493 allografts were provided and were utilized in 3643 patients. The allografts were used mainly by orthopedic surgeons (62%) and dentists (30%). The most used allografts were morcellized cancellous bone 31%, pulverized 25% and chips of cancellous bone 20%. Among orthopedic patients the most frequent procedures were related with spine degenerative diseases 39.09%, followed by non-pathological fractures and its complications 28.67% and bone tumors and cystic bone lesions 11.59%. Conclusions: Sustained increase of allograft utilization in Mexico reflects a great necessity for them in our country. The increase in public awareness about tissue donation has allowed an increase in tissue donations and retrievals.     

No influence of collagenous proteins of Achilles tendon, skin and cartilage on the virus-inactivating efficacy of peracetic acid–ethanol

The risk of transmitting human pathogenic viruses via allogeneic musculoskeletal tissue transplants is a problem requiring effective inactivation procedures. Virus safety of bone transplants was achieved using peracetic acid (PAA)-ethanol sterilisation. Proteins are known to have an adverse effect on the virus-inactivating capacity of PAA. Therefore we investigated virus inactivation by PAA in collagenous tissues. Achilles tendon, skin and cartilage were cut into small pieces, lyophilised and contaminated with pseudorabies virus (PRV) or porcine parvovirus (PPV). The inactivating capacity of PAA-ethanol was investigated by determining virus titres in the supernatant or the tissue pellet at different time-points. In all virus-contaminated tissue samples treatment for 10 min with PAA-ethanol resulted in titre reductions by a factor of >10(3). PRV was rapidly inactivated below the detection limit (< or =2.8 x 10(1) TCID(50)/ml). After 240 min a reduction by a factor of >10(4) was obtained for PPV in all samples, but a residual infectivity remained. Collagenous proteins of Achilles tendon, skin and cartilage had no adverse effect on the virus-inactivating capacity of PAA. PAA-ethanol used in the production process at the Charité tissue bank can therefore be recommended for treatment of non-osseous musculoskeletal tissues.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Chile

The Tissue Banking Project in Chile started as an idea in 1996. Before 1996 in Chile there were only a few small bone banks working with their own standards of quality. The first tissue bank (LPTR) was established in 1998, with the technical and financial support of the IAEA. Since 2001, the laboratory began to produce tissues for clinical use, starting with the processing of 6 amniotic membranes, 2 femoral heads and 19 batches of pig skin. In 2002, the laboratory began the processing of human skin. Five students from Chile have graduated from training courses carried out in Singapore and in Buenos Aires under the IAEA training program since 1998. The amount of tissues produced and sterilized using ionizing radiation by the LPTR in the last years was 320,000 cm² of human skin, 553,600 cm² of pig skin, 5,400 cm² of amniotic membrane, 49 femoral heads, 3 large bones and 300 g of bovine bone. The patients treated with sterilized tissues produced by the LPTR were 200 deep burns treated with human skin and pig skin, 40 bone transplants from femoral heads, 77 ophthalmologic patients treated with amniotic membrane and 150 bovine bone transplants for dental treatments.     

组织器官三维构建及原位组织工程概念——组织工程连载之四

组织器官三维构建就是把种子细胞和支架材料结合而获得设计的组织或器官,属于组织工程的核心内容,也最能体现组织工程的技术水平,如血管、气管的构建。由于传统组织工程存在缺陷,Shimizu于1998年首先提出了原位组织工程的概念,它是运用组织工程学基本原理,通过各种方法诱导移植的外源性的种子细胞或内源性的缺损组织局部细胞发生迁移、增殖、分化形成新生组织修复缺损。原位组织工程最大的特点是不依赖体外的细胞培养装置--生物反应器。原位组织工程是传统离体组织工程的有益补充。离体组织工程仍具有广阔的发展前景。     

Development of hematopietic and lymphoid tissues in conjoint bone marrow and thymus transplants]

The model of heterotopic transplantation of the mixture of bone marrow and thymus fragments was used to study the interaction of hemopoietic and lymphoid tissues under their direct contact. The bone marrow and thymus fragments of adult mice F1 (CBAXXC57BL) were transplanted separately or in the mixture under the kidney capsule of mice of the same strain. During the whole period of observation (from 10 days up to 14 months), the development of bone marrow and thymus fragments in the joint transplants proceeded independently, no "mixed" stroma appeared, and the stroma of each organ ensured the differentiation characteristic of its organ. The development of joint transplants somewhat differs from that of isolated transplants: on the 10th day a greater amount of hemopoietic tissues was noted in the former; the bone marrow component increases continuously up to 6 months (vs. 1--2 months in the isolated transplants); the bone and hemopoietic tissues predominate in the joint transplants by 14 months, the amount of thymic tissue markedly decreases but it does not disappear completely.     

Regenerative biology and medicine

The replacement of damaged tissues and organs with tissue and organ transplants or bionic implants has serious drawbacks. There is now emerging a new approach to tissue and organ replacement, regenerative biology and medicine. Regenerative biology seeks to understand the cellular and molecular differences between regenerating and non-regenerating tissues. Regenerative medicine seeks to apply this understanding to restore tissue structure and function in damaged, non-regenerating tissues. Regeneration is accomplished by three mechanisms, each of which uses or produces a different kind of regeneration-competent cell. Compensatory hyperplasia is regeneration by the proliferation of cells which maintain all or most of their differentiated functions (e.g., liver). The urodele amphibians regenerate a variety of tissues by the dedifferentiation of mature cells to produce progenitor cells capable of division. Many tissues contain reserve stem or progenitor cells that are activated by injury to restore the tissue while simultaneously renewing themselves. All regeneration-competent cells have two features in common. First, they are not terminally differentiated and can re-enter the cell cycle in response to signals in the injury environment. Second, their activation is invariably accompanied by the dissolution of the extracellular matrix (ECM) surrounding the cells, suggesting that the ECM is an important regulator of their state of differentiation. Regenerative medicine uses three approaches. First is the transplantation of cells into the damaged area. Second is the construction of bioartificial tissues by seeding cells into a biodegradable scaffold where they produce a normal matrix. Third is the use of a biomaterial scaffold or drug delivery system to stimulate regeneration in vivo from regeneration-competent cells. There is substantial evidence that non-regenerating mammalian tissues harbor regeneration-competent cells that are forced into a pathway of scar tissue formation. Regeneration can be induced if the factors leading to scar formation are inhibited and the appropriate signaling environment is supplied. An overview of regenerative mechanisms, approaches of regenerative medicine, research directions, and research issues will be given.     

Tissue engineering: generation of differentiated artificial tissues for biomedical applications

A new field in biomedical science has been established. Cell biologists, engineers, and surgeons now work within a team. Artificial connective, epithelial, or neuronal tissues are being constructed using living cells and different kinds of biomaterials. Numerous companies and laboratories are presenting dynamic developments in this field. Prognoses predict that, at the beginning of the coming century, the industry of tissue engineering will reach the importance of the present genetic technology. An enormous demand for organ and tissue transplants motivates research activities and drives the acquisition of innovative techniques and creative solutions. At the front of this development is the creation of artificial skin for severely burned patients and the generation of artificial cartilage for implantation in articular joint diseases. Future challenges are the construction of liver organoids and the development of an artificial kidney on the basis of cultured cells. In this paper we show strategies, needs, tools, and equipment for tissue engineering. The presupposition for all projects is the induction, development, and maintenance of differentiation within the tissue under in vitro conditions. As experiments in conventional culture dishes continued to fail, new cell and tissue culture methods had to be developed. Tissues are cultured under conditions as close as possible to their natural environment. To optimize adherence or embedding, cells are grown on novel tissue carriers and on individually selected biomatrices or scaffolds. The tissues are subsequently transferred into different types of containers for permanent perfusion with fresh culture medium. This guarantees constant nutrition of the developing tissue and prevents the accumulation of harmful metabolites. An organo-typical environment for epithelial cells, for example, is obtained in gradient containers, which are permanently superfused at the apical and basal sides with different media. Long term experiments result in cultured tissues in a quality thus far unreached.     

Tissue engineering for clinical applications

Tissue engineering is increasingly being recognized as a beneficial means for lessening the global disease burden. One strategy of tissue engineering is to replace lost tissues or organs with polymeric scaffolds that contain specialized populations of living cells, with the goal of regenerating tissues to restore normal function. Typical constructs for tissue engineering employ biocompatible and degradable polymers, along with organ-specific and tissue-specific cells. Once implanted, the construct guides the growth and development of new tissues; the polymer scaffold degrades away to be replaced by healthy functioning tissue. The ideal biomaterial for tissue engineering not only defends against disease and supports weakened tissues or organs, it also provides the elements required for healing and repair, stimulates the body's intrinsic immunological and regenerative capacities, and seamlessly interacts with the living body. Tissue engineering has been investigated for virtually every organ system in the human body. This review describes the potential of tissue engineering to alleviate disease, as well as the latest advances in tissue regeneration. The discussion focuses on three specific clinical applications of tissue engineering: cardiac tissue regeneration for treatment of heart failure; nerve regeneration for treatment of stroke; and lung regeneration for treatment of chronic obstructive pulmonary disease.     

Carbon nanotubes leading the way forward in new generation 3D tissue engineering

Statistics from the NHS Blood and Transplant Annual Review show that total organ transplants have increased to 4213 in 2012, while the number of people waiting to receive an organ rose to 7613 that same year. Human donors as the origin of transplanted organs no longer meet the ever-increasing demand, and so interest has shifted to synthetic organ genesis as a form of supply. This focus has given rise to new generation tissue and organ engineering, in the hope of one day designing 3D organs in vitro. While research in this field has been conducted for several decades, leading to the first synthetic trachea transplant in 2011, scaffold design for optimising complex tissue growth is still underexplored and underdeveloped. This is mostly the result of the complexity required in scaffolds, as they need to mimic the cells’ native extracellular matrix. This is an intricate nanostructured environment that provides cells with physical and chemical stimuli for optimum cell attachment, proliferation and differentiation. Carbon nanotubes are a popular addition to synthetic scaffolds and have already begun to revolutionise regenerative medicine. Discovered in 1991, these are traditionally used in various areas of engineering and technology; however, due to their excellent mechanical, chemical and electrical properties their potential is now being explored in areas of drug delivery, in vivo biosensor application and tissue engineering. The incorporation of CNTs into polymer scaffolds displays a variety of structural and chemical enhancements, some of which include: increased scaffold strength and flexibility, improved biocompatibility, reduction in cancerous cell division, induction of angiogenesis, reduced thrombosis, and manipulation of gene expression in developing cells. Moreover CNTs’ tensile properties open doors for dynamic scaffold design, while their thermal and electrical properties provide opportunities for the development of neural, bone and cardiac tissue constructs.     

The preservation of tissues for transplantation

This paper is a written version of a lecture given during the celebration of Professor Rudolf Klen’s 90th birthday. Dr. Klen played by far the major part in the introduction and the development of Tissue Banking in Europe. His concept of a tissue bank envisaged the storage of all types of cell, tissue and organ that physicians and surgeons might need for the treatment of their patients. There has been much progress towards this goal, but still the final objective remains elusive. This review of the current position starts with the recognition that some tissues are required to comprise or include cells that exhibit all the formal characteristics of life if they are to function as grafts, whereas other tissues do not. For some tissues, the preservation of mechanical properties is crucial: for others it is not. These considerations are crucial for the design of preservation methods for specific tissues: bone tendon and skin can provide useful grafts in the absence of living cells and this may even be true of cardiac valves: the crucial requirement here is that the mechanical properties remain intact. Simply freezing at around −80°C may be sufficient. In contrast, many cell systems, and all metabolizing organs do require healthy cells to function. Cryopreservation is often an effective remedy for isolated cells, for example haemopoietic stem cells, but the damaging effects of the formation of ice are sufficient to rule out this approach for whole vascularised organs and for some tissues too. The damaging mechanisms are discussed, and it is concluded that the site of ice crystallization is crucial. Cartilage has hitherto been recalcitrant, but we have recently developed a method that permits this tissue to be stored at liquid nitrogen temperatures without any ice and with the recovery of living cells and intact mechanical properties after storage. Thus, many methods are available to help develop tissue banking originally envisioned by Dr. Klen.     

Immunologic 'ignorance' of vascularized organ transplants in the absence of secondary lymphoid tissue

Secondary lymphoid organs (the spleen, lymph nodes and mucosal lymphoid tissues) provide the proper environment for antigen-presenting cells to interact with and activate naive T and B lymphocytes. Although it is generally accepted that secondary lymphoid organs are essential for initiating immune responses to microbial antigens and to skin allografts, the prevailing view has been that the immune response to primarily vascularized organ transplants such as hearts and kidneys does not require the presence of secondary lymphoid tissue. The assumption has been that the immune response to such organs is initiated in the graft itself when recipient lymphocytes encounter foreign histocompatibility antigens presented by the graft's endothelial cells. In contrast to this view, we show here that cardiac allografts are accepted indefinitely in recipient mice that lack secondary lymphoid tissue, indicating that the alloimmune response to a vascularized organ transplant cannot be initiated in the graft itself. Moreover, we demonstrate that the permanent acceptance of these grafts is not due to tolerance but is because of immunologic 'ignorance'.     

Basics of immune responses in transplantation in preparation for application of composite tissue allografts in plastic and reconstructive surgery: part I

Currently, composite tissue allografts are applied only occasionally as a reconstructive option in the field of plastic and reconstructive surgery. Composite tissue allografts offer a unique potential for coverage of large multitissue defects. However, compared with the relatively homogenous tissue of solid organ transplants, the heterogenicity of tissue components of composite tissue allografts may generate high immunologic responses. Modern immunosuppressive agents significantly improve successful allograft acceptance. However, chronic allograft rejection and immunosuppressive drug toxicity are still major problems in the clinical practice of transplantation. The major goals of transplantation immunology are (1) to develop tolerance to allograft transplants and (2) long-term drug-free survival. A number of experimental protocols were designed to develop tolerance; however, none of them has been proven to induce tolerance in clinical transplantation. In this article, the authors outline the mechanisms of allograft acceptance and rejection and barriers to transplantation tolerance. Novel immunosuppressive protocols are discussed in this review. This basic immunologic knowledge of allograft acceptance and rejection will allow plastic surgeons to apply composite tissue allograft transplants to plastic and reconstructive surgery.     

Adrenocortical cell transplantation in scid mice: the role of the host animals' adrenal glands

Adrenocortical cell transplantation is a powerful technique for the investigation of the regulation of adrenocortical structure and function. Some classical organ and tissue transplantation experiments suggest that the success of transplantation depends on the activity of the pituitary gland and other endocrine systems, and is therefore influenced by the host animals’ own adrenal glands. For this reason, our experiments have usually been performed on adrenalectomized animals. However, we show here that cell transplantation experiments, involving the introduction of bovine adrenocortical cells into scid mice, do produce transplant tissues in the presence of the host animals’ adrenal glands. However, the tissue that forms is small and its cells also smaller than usual. When the adrenals of such animals are removed in a second surgical procedure, the transplants show a rapid increase in steroidogenic function and a slower increase in size, over several weeks. We conclude that the initial process by which transplanted adrenocortical cells organize into a tissue structure is not affected by the presence of the host animals’ adrenal glands, but the growth of the transplants is limited until the adrenal glands are removed.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in India

The banking of tissues such bone and skin began in India in the 1980s and 1990s. Although eye banking started in 1945 there was little progress in this field for the next five decades. As part of the IAEA/RCA program to use ionising radiation for the sterilisation of biological tissues in Asia and the Pacific Region, the Tata Memorial Hospital (TMH) in 1986 decided to set up a tissue bank in Mumbai funded by the Government of India. The TMH Tissue Bank became operational in January 1988, and stands as a pioneering effort in the country to provide safe, clinically useful and cost-effective human allografts for transplantation. It uses the IAEA International Standards on Tissue Banking. All the grafts are sterilised terminally by exposure to a dose of 25 kGy of gamma radiation, which has been validated as recommended by the IAEA Code of Practice for the Radiation Sterilisation of Tissues Allografts: Requirements for Validation and Routine Control. The TMH Tissue Bank is registered with the Maharashtra State Health Authorities, and in May 2004, it became India’s first Tissue Bank to receive ISO 9001:2000 certification of its Quality Management System. From 1989 to September 2007, the TMH Tissue Bank has supplied 11,369 allografts to 310 surgeons operating in 69 hospitals in Mumbai and 56 hospitals in other parts of India. These numbers have been limited by difficulties with the retrieval of tissues from deceased donors due to inadequate resources and tissue donation policies of hospitals. As the Government of India representative in the IAEA program, the TMH Tissue Bank has promoted and co-coordinated these activities in the country and the development of tissue banks using radiation sterilisation of tissue grafts. Towards this end it has been engaged in training personnel, drawing up project proposals, and supporting the establishment of a Tissue Retrieval Centre in Mumbai. Currently it networks with the Zonal Transplant Co-ordination Centre of the Government of Maharashtra, and the newly instituted National Deceased Donor Transplantation Network, which will work with the Government of India to set up rules and regulations for organ and tissue donation and transplantation.     

Adrenocortical cell transplantation in scid mice: the role of the host animals’ adrenal glands

Adrenocortical cell transplantation is a powerful technique for the investigation of the regulation of adrenocortical structure and function. Some classical organ and tissue transplantation experiments suggest that the success of transplantation depends on the activity of the pituitary gland and other endocrine systems, and is therefore influenced by the host animals’ own adrenal glands. For this reason, our experiments have usually been performed on adrenalectomized animals. However, we show here that cell transplantation experiments, involving the introduction of bovine adrenocortical cells into scid mice, do produce transplant tissues in the presence of the host animals’ adrenal glands. However, the tissue that forms is small and its cells also smaller than usual. When the adrenals of such animals are removed in a second surgical procedure, the transplants show a rapid increase in steroidogenic function and a slower increase in size, over several weeks. We conclude that the initial process by which transplanted adrenocortical cells organize into a tissue structure is not affected by the presence of the host animals’ adrenal glands, but the growth of the transplants is limited until the adrenal glands are removed.     

Electroconductive materials as biomimetic platforms for tissue regeneration

In many diseases, tissue regeneration is compromised and/or insufficient to restore tissue/organ function. Therefore, novel regenerative therapies are being developed to enhance resident and transplanted cell proliferation and functional differentiation. Numerous biomaterials engineered to include nanocomponents have emerged as promising candidates to fulfil the need of mimicking the properties of the healthy extracellular matrix. This is particularly important for tissues that require electroconductive support to achieve optimal cellular function, such as muscles and neurons. In this review, we summarize and discuss the current state-of-the-art for electroconductive materials in tissue regeneration, with particular emphasis on materials containing nanocomponents.     

The impact of the International Atomic Energy Agency (IAEA) program on radiation and tissue banking in Argentina

Tissue banking activities in Argentina started in 1993. The regulatory and controlling national authority on organ, tissue and cells for transplantation activity is the National Unique Coordinating Central Institute for Ablation and Implant (INCUCAI). Three tissue banks were established under the IAEA program and nine other banks participated actively in the implementation of this program. As result of the implementation of the IAEA program in Argentina and the work done by the established tissue banks, more and more hospitals are now using, in a routine manner, radiation sterilised tissues processed by these banks. During the period 1992–2005, more than 21 016 tissues were produced and irradiated in the tissue banks participating in the IAEA program. Within the framework of the training component of the IAEA program, Argentina has been selected to host the Regional Training Centre for Latin American. In this centre, tissue bank operators and medical personal from Latin American countries were trained. Since 1999, Argentina has organised four regular regional training courses and two virtual regional training courses. More than twenty (20) tissue bank operators and medical personnel from Argentina were trained under the IAEA program in the six courses organised in the country. In general, ninety (96) tissue bank operators and medical personnel from eight Latin-American countries were trained in the Buenos Aires regional training centre. From Argentina 16 students graduated in these courses.