Transplanted hNT Cells (“LBS Neurons”) in a Rat Model of Huntington’s Disease: Good Survival, Incomplete Differentiation, and Limited Functional Recovery
A variety of immortalized cell lines have been proposed to exhibit sufficient phenotypic plasticity to allow them to replace primary embryonic neurons for restorative cell transplantation. In the present experiments we evaluate the functional viability of one particular cell line, the hNT cells developed by Layton Bioscience, to replace lost neurons and alleviate asymmetrical motor deficits in a unilateral excitotoxic lesion model of Huntington’s disease. Because the grafts involved implantation of human-derived cells into a rat host environment, all animals were immunosuppressed. Cyclosporin A and FK-506 were similar in providing effective immunoprotection of the hNT xenografts, and whereas the lesions induced a marked inflammatory response in the host brain, this was not exacerbated by the presence of xenograft cells. The presence of grafted cells was determined with the human-specific antigen HuNu, and good graft survival was demonstrated in almost all animals up to the longest survival examined, 16 weeks posttransplantation. Although the cells exhibited progressively greater maturation and differentiation at 10-day, 4- and 16-week time points, staining for the mature neuronal marker NeuN was at best very weak, and we were unable to detect unequivocal staining with any markers of mature striatal phenotype, including DARPP-32, calbindin, parvalbumin, choline acetyl transferase, or NADPH diaphorase (with in all cases positive control provided by good staining on the intact contralateral side of the brain). Nor were we able to detect any differences between rats with lesions alone and rats with grafts in the contralateral motor deficits exhibited in a test of skilled paw reaching or cylinder placing. These results suggest that further and more extensive studies should be undertaken to assess whether hNT neurons can show more extensive and appropriate maturation and be associated with recovery in appropriate behavioral models, before they may be considered a suitable replacement for primary embryonic cells for clinical application in Huntington’s disease.
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Cell Transplantation publishes original, peer-reviewed research and review articles on the subject of cell transplantation and its application to human diseases. To ensure high-quality contributions from all areas of transplantation, separate section editors and editorial boards have been established. Articles deal with a wide range of topics including physiological, medical, preclinical, tissue engineering, and device-oriented aspects of transplantation of nervous system, endocrine, growth factor-secreting, bone marrow, epithelial, endothelial, and genetically engineered cells, among others. Basic clinical studies and immunological research papers are also featured. To provide complete coverage of this revolutionary field, Cell Transplantation will report on relevant technological advances, and ethical and regulatory considerations of cell transplants. Cell Transplantation is now an Open Access journal starting with volume 18 in 2009, and therefore there will be an inexpensive publication charge, which is dependent on the number of pages, in addition to the charge for color figures. This will allow work to be disseminated to a wider audience and also entitle the corresponding author to a free PDF, as well as prepublication of an unedited version of the manuscript.