Cryopreservation, culture, and transplantation of human fetal mesencephalic tissue into monkeys

Susceptibility of human foetal brain tissue to cool- and freeze-storage

Human second trimester foetal brain tissue was stored for a period of 1-6 weeks under various conditions in an attempt to evaluate factors influencing its susceptibility (cell loss) and survivability. Post-storage viability of mesencephalon, striatum, cerebellum and occipital cortex was assessed by a protocol combining vital staining with cell density counts so that tissue viability and cell loss could be evaluated simultaneously; tissue survivability was evaluated by cell culture. A significant amount of cell loss occurred after 24 h storage at room temperature, after one week at 4 degrees C and by two weeks at -20 degrees C in all structures; storage at -196 degrees C resulted in 17-21% cell loss at the end of a 6 week period. At -20 degrees C the cryoprotective effect of 20% FCS was equivalent to that of 15% FCS + 7% DMSO combined, suggesting potential use of serum in replacement of chemical additives. The procedure for removal of DMSO was critical to cell viability and survivability: single step dilution led to 27-39% greater cell loss than slow, multi-step dilutions. In comparison to fresh, non-stored tissue, immunocytochemical characterization of in vitro propagated stored tissue revealed no changes in the populations of major constituent cell types including neurones, dopaminergic neurones, glial and fibroblast cells. These results provide information on possible conditions under which transplant tissue can be satisfactorily stored depending on the prevailing requirements.

Cryopreservation and culture of the human fetal brain tissues

Human embryos after 3-4.5 months of gestation were obtained with abortion. The brain tissue of the bodies was scissored up to obtain 1-3 mm3 pieces, and 7% dimethyl sulfoxide (DMSO), as a cryoprotectant, was added, and then stored at -70 degrees C for 1-30 days or at -196 degrees C for 1-84 days. The survival rate of stored cells was 64%-88%. During 6 days of storage with neuron culture medium, the survival rate of cells at 4 degrees C is over 50% each day, but, as time goes on, the count of the cells is getting less and less. The cells washed out DMSO after cryopreservation and the planting fresh cells can adhere to the wall of the culture bottle, grow, display various forms of neurons and gliacytes. From the above findings, it was suggested that: 1) The fetal human brain tissue, handled properly, can endure cryopreservation with 7% DMSO as a cryoprotective agent; 2) The storage time was related insignificantly to the survival rate of the tissues stored; 3) It is available for a short preservation at 4 degrees C; and 4) It is possible to set up a bank of fetal human brain tissue.

Cerebral transplantation for Parkinson's disease: current progress and future prospects

Cerebral transplantation has received considerable attention from both the medical community and lay press as a potential treatment for Parkinson's disease. Animal models have demonstrated feasibility, although the experience in subhuman primates was very limited when the first human trials were initiated in the mid-1980s. The dramatic success reported for adrenal-to-brain transplantation in some initial trials could not be consistently replicated by other centers. Occasionally, however, patients benefited. Failure of the adrenal medullary graft to survive may have been a major factor in the poor outcomes. Recently, several US and European centers reported substantial clinical improvement after fetal dopaminergic mesencephalon was grafted into the striatum of patients with Parkinson's disease. Although many outcomes were impressive, in some cases the improvement was marginal; in no case was the condition completely reversed, and all but one patient still required levodopa therapy. Before this technique can be considered for routine use, further refinement is necessary, and many technical issues must be addressed. Certain animal studies have suggested that transplantation-related improvement may be derived from graft neurotrophic factors rather than from secretion of dopamine into the dopamine-depleted brain of patients with Parkinson's disease. Preliminary investigations in animals indicate that several other tissues, besides fetal mesencephalon, may also prove appropriate for grafting. Ultimately, advances in molecular biology may allow either transplantation of genetically engineered cells or direct modification of existing brain cells by transfection with viral vectors. The favorable preliminary experience with cerebral transplantation in patients with Parkinson's disease has resulted in the consideration of this strategy for other neurologic disorders.

Intracerebral grafting of catecholamine producing cells and reconstruction of disturbed brain function

The objective of neural transplantation is to improve and reconstruct deteriorated brain function through an intracerebral implant of neural or paraneural tissues. In the last decade, basic research in this field has made great progress and brought magnificent results. Recently, the clinical application for treatment of Parkinson's disease has started and some fruitful effects are seen. Neural transplantation, on the other hand, is a useful tool in neurobiology to study the attention attracting themes, i.e., regeneration, development, plasticity, gene expression, neuroimmunology, trophic factor, etc. In this review, the functional recovery, mechanism, trophic factor, and clinical applications will be discussed pertaining to intracerebral grafting of catecholamine producing cells.

Unilateral transplantation of human fetal mesencephalic tissue into the caudate nucleus of patients with Parkinson's disease

BACKGROUND

Parkinson's disease is characterized by the loss of midbrain dopamine neurons that innervate the caudate and the putamen. Studies in animals suggest that fetal dopaminergic neurons can survive transplantation and restore neurologic function. This report compares the clinical results in four case patients with severe Parkinson's disease who underwent stereotaxic implantation of human fetal ventral mesencephalic tissue in one caudate nucleus with the results in a control group of similar subjects assigned at random to a one-year delay in surgery.

METHODS

Each case patient received cryopreserved tissue from one fetal cadaver (gestational age, 7 to 11 weeks). Before implantation, adjacent midbrain tissue underwent microbiologic, biochemical, and viability testing. Cyclosporine was administered for six months postoperatively.

RESULTS

The procedure was well tolerated. Three case patients showed bilateral improvement on motor tasks, as assessed on videotape, and were more functional in the activities of daily living, as assessed by themselves and neurologists, during both optimal drug therapy and "drug holiday" periods. One case patient, who died after four months from continued disease progression, had striatonigral degeneration at autopsy. In the patients who received transplants, optimal control was achieved with a lower dose of antiparkinsonian medications, whereas the controls required more medication. Positron-emission tomography with [18F]fluorodopa before and after surgery in one patient revealed a bilateral restoration of caudate dopamine synthesis to the range of normal controls, but continued bilateral deficits in the putamen.

CONCLUSIONS

Although the case patients continued to be disabled by their disease, unilateral intracaudate grafts of fetal tissue containing dopamine diminished the symptoms and signs of parkinsonism during 18 months of evaluation.

Cryopreservation, survival and function of intrastriatal fetal mesencephalic grafts in a rat model of Parkinson's disease

In the present study we quantitatively assessed to what extent freeze-storage at liquid nitrogen temperature influences the survival and function of fetal mesencephalic grafts in the dopamine-depleted rat striatum. Ventral mesencephalic (VM) tissue was dissected from rat fetuses and stored overnight in a preservative medium at 4 degrees C (hibernation). It was grafted intrastriatally either as a fresh cell suspension or was frozen as tissue fragments or as a cell suspension after stepwise incubation in ascending concentrations of dimethyl-sulphoxide. Following a cryopreservation interval of 80 days in liquid nitrogen, the frozen samples were rapidly thawed, rinsed, and grafted. Cellular viabilities of graft cell suspensions, as assessed by ethidium bromide/acridine orange staining, were decreased from 90% in fresh tissue to 38-35% in frozen and thawed tissue. Amphetamine-induced turning behavior at 6 weeks post-grafting was significantly attenuated in hosts that had received fresh grafts or grafts that were frozen as tissue fragments. Tyrosine hydroxylase-(TH-) immunocytochemistry of recipient brains revealed significant decreases in TH-positive graft cell numbers in rats grafted with cryopreserved tissue (38-42% of fresh tissue). Moreover, the dye exclusion viability of thawed VM tissue was found to accurately predict the subsequent graft survival. There was no difference with respect to graft cell numbers between the two freezing methods employed, though block storage seems to be more simple from a practical point of view.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell cultures from cryopreserved human lung tissue

To assess gene induction in primary human fibroblasts, we have developed a method for cryopreservation of lung biopsies in liquid nitrogen. Fresh biopsies (n = 10) were chopped into 5 x 5 mm pieces and transferred into an ice-cold freezing medium. Biopsies were kept on ice for 15 min, followed by further cooling of the tissue to -70 degrees C. With this method, lung biopsies were preserved for more than 1 year before they were used for generating cell cultures. There was no significant difference in the biological responsiveness of fibroblasts generated from immediately cultured lung biopsies compared with those from cryopreserved tissue. The doubling rate of fibroblasts from fresh tissue was 23.6 +/- 1.1 hr; compared to 23.5 +/- 1.5 hr for fibroblasts generated from cryopreserved tissue. PDGF-BB enhanced de novo synthesis of DNA 100 times, in both the immediately cultured fibroblasts and those generated from cryopreserved biopsies. Macrophages, dendritic cells and endothelial cells could also be recovered from cryopreserved lung tissue. This method permits long-term storage of lung tissue and the possibility of establishing primary cell lines from the same tissue at later times without appreciable changes in their cellular biological characteristics.

A novel approach to neural transplantation in Parkinson's disease: use of polymer-encapsulated cell therapy

Transplantation of dopaminergic neurons derived from fetal or adrenal tissue into the striatum is a potentially useful treatment for Parkinson's disease (PD). Although initially promising, recent clinical studies using adrenal autografts have demonstrated limited efficacy. The use of human fetal cells, despite promising preliminary results, is complicated by tissue availability and ethical concerns. An attractive alternative is based on encapsulating dopamine-producing cells into polymer capsules prior to transplantation. Polymer capsules can be fabricated to surround the cells with a semi-permeable and immunoprotective barrier. The semi-permeable membrane allows nutrients to enter the capsule, so the encapsulated cells will survive and function, and dopamine and other low molecular weight constituents to diffuse out into the host tissue. Thus, the technique allows use of unmatched human tissue (allografts), or even animal tissue (xenografts) without immunosuppression of the recipient. Cell-loaded polymer capsules can also be retrieved if necessary or desired. The demonstration that striatal implants of encapsulated dopamine-producing cells promote behavioral recovery in rodent and primate models of PD further suggests that cellular encapsulation may be a useful strategy for ameliorating the behavioral consequences of PD.

Cryopreservation and transplantation of immature rat retina into adult rat retina

A bank of freeze-stored donor retinas would free transplantation research from dependence on availability of fresh donor tissue. Donor retinas from E13, E16, E19 and E22 (P1) rat embryos were cryoprotected and stored in liquid nitrogen for up to 8 months. Cryopreserved and fresh donor retinas were grafted to adult rat retina. After 4 weeks survival, transplants were evaluated according to a scoring protocol for the criteria of size, viability, lamination and integration. All donor ages of fresh and cryopreserved retina resulted in successful transplants, with the exception of cryopreserved E13. Cryopreserved grafts were significantly less laminated than grafts of fresh tissue. The best lamination scores of cryopreserved transplants were achieved with donor age E16. Surviving transplants were found in the epiretinal and/or subretinal space. Subretinal transplants had higher viability scores than did epiretinal grafts; the difference was more pronounced with transplants of cryopreserved than with fresh tissue. Fresh subretinal transplants were also significantly better laminated than fresh epiretinal transplants. This study shows that (1) cryopreserved retinal donor tissue can successfully be transplanted to rat retina; and (2) the subretinal space appears to be more favorable than the epiretinal space for retinal transplants.

Neural transplantation for Parkinson's disease: a critical appraisal

The medical treatment of severe Parkinson's disease is presently problematical and neural transplantation has been proposed as an additional therapy. While functional improvement in animal models of Parkinson's disease has been reported following neural grafting, the treatment of human Parkinsonian patients by adrenal medulla autografting into the neostriatum has produced little clinical improvement overall, and is associated with significant morbidity. Although recent grafting of human foetal dopaminergic neurons has shown more promise, many of the case reports lack rigorous assessment and long term follow-up. Further laboratory experimentation in animal models, particularly primates, to ascertain the mechanism of action of the grafts, the optimal sites for grafting, and the immunological responses to grafting, is essential. The future success of neural transplantation for Parkinson's disease may depend on the development of novel strategies such as the use of growth factors to aid cell survival, regulate neurotransmitter levels and promote connectivity. However, at present, the clinical application of neural transplantation for Parkinson's disease is premature.

Cell culture of cryopreserved human fetal cerebral cortical and hippocampal neurons: neuronal development and responses to trophic factors

Past knowledge of the human brain at the cellular and molecular levels has come largely from studies of postmortem fixed tissue or by way of extrapolation from studies of lower mammalian species. The ability to study living human brain neurons would provide a new avenue for further insight into mechanisms operative in human brain development, function, and disease. The present study established procedures for the cryopreservation and culture of human fetal cerebral cortical and hippocampal neurons, and characterized the development of the cells in culture. The predominant cell type in both cortical and hippocampal cultures was pyramidal-like neurons that extended one long axon-like process and a few minor dendrite-like processes. Bipolar and stellate cells, as well as astrocyte-like glia were also present in cultures from both brain regions. Fibroblast growth factor (FGF), but not nerve growth factor (NGF), enhanced long-term neuronal survival in both cerebral cortical and hippocampal cultures. Immunocytochemistry demonstrated the presence of both FGF- and NGF-like immunoreactivities in neurons and glia, from both cerebral cortex and hippocampus, suggesting that these endogenous growth factors may play roles in human fetal brain development. The ability to cryopreserve large numbers of viable dissociated human fetal brain neurons, and subsequently study them in cell cultures, provides new opportunities to understand dynamic aspects of the human brain at the cellular and molecular levels.

The selective viability of human foetal brain cells

The influence of various factors upon the survival of human foetal neurones has been examined. The viability of several brain structures was assessed using ethidium bromide and acridine orange fluorescence in both 'intact' and mechanically dispersed tissue. Striatum was least vulnerable to dissociation while cortex, mesencephalon, pons, cerebellum and cord were more vulnerable to a greater or lesser extent. Material can be preserved in vitro with greater viability in the undissociated rather than dissociated state. The effects of other factors including foetal age upon viability are discussed.

Autotransplantation of superior cervical ganglion to the caudate nucleus in three patients with Parkinson's disease (preliminary report)

Striatal cervical ganglionic implants have been utilized for the first time for treatment of three patients suffering from Parkinson's disease. Tissue grafts from the superior cervical ganglion have been dissected and immediately transplanted into the head of the caudate nucleus. The grafted tissue placed in a cavity of the caudate nucleus remains in contact with the cerebrospinal fluid in the lateral ventricle. Three and six months after surgery, none of the patients has had any major complications and their lower score of Unified Parkinsonism Rating Scale (UPRS) points was associated with an improvement of the signs of Parkinson's disease. Present data have provided some optimism that grafting of superior cervical ganglion is a feasible approach in Parkinson's disease.

Transplantation of human sympathetic neurons and adrenal chromaffin cells into parkinsonian monkeys: no reversal of clinical symptoms

Cultured human fetal sympathetic ganglion explants or adrenal chromaffin cell aggregates were implanted into the left striatum of monkeys whose left nigrostriatal pathway had been lesioned with the neurotoxin MPTP. There was no clinical reversal of parkinsonian symptoms and PET scans did not show increased striatal fluorodopa uptake from pre-implant levels. At sacrifice, left striatal contents of dopamine were not statistically different from MPTP-treated but non-implanted controls. Histological examinations revealed pockets of extrinsic cells which were found at the end of needle tracks. There was no evidence of immune rejection. The extrinsic cells did not stain for tyrosine hydroxylase or neurofilament, suggesting that they were not dopaminergic neurons. The failure to reverse clinical parkinsonian symptoms highlights the stage of infancy of neural implantation in Parkinson's disease.

Reorganization of neuronal connections following CNS trauma: principles and experimental paradigms

The present review summarizes how the nervous system responds to trauma. The goal is to provide an introduction to the problems, techniques, experimental paradigms, current issues, and future promise. The review is especially designed for basic scientists and clinicians who are not currently involved in research on CNS reorganization, and for students just entering the field. The review characterizes the secondary degenerative events that occur after trauma, and the types of growth that commonly occur. A standard terminology is set forth with criteria for differentiating between related phenomena. Experimental methods are described that can be used documenting reorganization of circuitry. The principles that determine whether a given process will or will not occur are summarized, and some of the factors that may regulate the nature and extent of growth are considered. Research strategies are outlined that have been used to evaluate whether reorganization of circuitry is functionally significant. Finally, future directions in research and clinical application are discussed, focusing especially on the efforts to facilitate regeneration, and the work on transplants of CNS tissue to facilitate growth of surviving connections, and to replace tissue destroyed by trauma.