INTRODUCTION: Recently, human hand transplantation in Europe has shown that motor function may be recovered in some cases. However, little is known about cell trafficking involved the graft nerve. We have succeeded to use green fluorescent protein transgenic (GFP-Tg) rats with various cells strongly expressing GFP in a model a long-term survival of limb graft. In this model, we found retrograde migration of GFP-positive donor cells through the sclatic nerve anastomosis. It is well known that cellular components in the peripheral nerve graft especially Schwann cells, play an important role in the axonal regeneration promoted by nerve grafting. However, it was difficult to distinguish the cellular component of the nerve graft from recipient cells. The purpose of this study was to evaluate the migration of donor origin cells to the recipient's nerve and to examine the contribution of these cells in axonal regeneration using a simplified model of sciatic grafting. METHODS: Nerve defects were created in recipient rats, using three experimental combinations: group 1: wild-type rats from GFP Tg rats; group 2: GFP Tg rats from wild-type rats; group 3: wild-type rats from GFP Tg rats whose nerve grafts had been pretreated by freeze-thawing cycles (representing an acellular graft). The sciatic nerve specimens were examined under excitation light at 1, 2, and 3 weeks after transplantation. RESULTS: GFP-positive area expanded clearly beyond the anastomosis both proximally and distally in group 1 and infiltrated into the middle of the null graft in group 2. On the contrary, freeze-thawing grafts donated GFP Tg rats lost GFP expression completely. Columns of GFP-positive cells were formed in the degenerated graft migrated into the recipient's nerve both ante- and retrograde. The S100-positive GFP-positive cells were considered to be graft-origin Schwann cells. The regenerating axons were accompanied with these double-positive cells in the recipient nerve. In conclusion, we have visualized the contribution of graft cells to axonal regeneration beyond a peripheral nerve anastomosis.

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PubMedDate not supplied

A novel immunomodulator KRP-203 combined with cyclosporine prolonged graft survival and abrogated transplant vasculopathy in rat heart allografts.

To find more effective and less toxic immunosuppressive strategies in long-term treatment for organ transplantation patients, we examined the effects on rat heart allograft survival of a novel sphigosine-1-phosphate receptor agonist, KRP-203, combined with a subtherapeutic dose of cyclosporine (CsA). Rat heart transplantation was performed across a major histocompatibility complex-incompatible (DA to LEW) rat combination. KRP-203 alone showed little or no effect on heart allograft survival. In contrast, KRP-203 combined with a subtherapeutic dose of CsA led to prolonged allograft survival. Histologic analyses showed that the combination completely suppressed acute rejection, as characterized by allograft vasculopathy, mononuclear cell infiltration, and myocardial necrosis in the heart allografts. RT-PCR analysis showed that the allografts treated with CsA or KRP-203 alone showed no suppression of IL-10, IFN-gamma, and TNF-alpha mRNA expression, but when combined with a subtherapeutic dose of CsA it completely suppressed their mRNA expressions. Furthermore, the combination treatment reduced donor-specific antibody production. KRP-203 combined with a subtherapeutic dose of CsA synergistically prolonged rat heart allograft survival. The combination of CsA with KRP-203 may provide an option to prevent allograft rejection and reduce adverse effects.

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PubMedDate not supplied

Composite tissue transplantation in rats: fusion of donor muscle to the recipient site.

UNLABELLED: Little information currently exists on the repair of muscular tissue at the site of an amputation stump. This study examined the healing process of muscular tissue following composite limb transplantation using transgenic rat models. METHODS: Green fluorescent protein (GFP) transgenic rats were used to study the process of connection of donor muscle with the recipient. A DsRed2/GFP double-reporter transgenic rat and an NCre transgenic rat were used to study cell fusion. These rats have the unique characteristic of changing red fluorescence to green fluorescence by Cre/LoxP recombination when cell-to-cell fusion occurs between the two transgenic strains. Orthotopic hind limb transplantation was performed in two combinations: GFP transgenic rat to Wild Wistar rat and DsRed2/GFP transgenic rat to NCre transgenic rat. RESULTS: We observed extension of donor-derived GFP(+) myofibers into recipient site a few weeks after limb transplantation. A histologic study of the DsRed2/GFP transgenic rat to the NCre transgenic rat combination showed that red myofibers of the DsRed2/GFP rat were partly replaced by green myofibers as a result of Cre-mediated recombination. PCR analysis detected both the recombined transgene (330 bp) and the nonrecombined gene (1420 bp) in muscle around the junction. These findings indicate that the muscles sutured between the amputation stumps fused with each other and that donor-recipient hybrid cells were formed at the muscle junction following limb transplantation. CONCLUSIONS: This basic information shows muscle fusion between donor and recipient at the site of composite tissue transplant using newly established transgenic rats.

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PubMedDate not supplied

Efficiency of adenovirus-mediated gene transduction in heart grafts in rats.

AIM: We determined the characteristics of transgene expression of heart grafts following ex vivo gene transfer using an adenovirus vector. Transgene expression was assessed periodically in the same animals by a non-invasive bioimaging system. METHODS: Rat heterotopic heart transplantation was performed in a syngenic combination. We infused 1 x 10(9) plaque-forming units of adenovirus vectors containing firefly luciferase gene into the heart graft via the coronary artery, with preservation at 4 degrees C and transplanted into the cervix of the recipient. Transgene expression was periodically visualized and quantified by a noninvasive bioimaging system without sacrificing experimental animals. RESULTS: Transgene expression in the graft peaked at day 7 and then fell gradually. Transgene expression was also observed in the recipient liver. CONCLUSIONS: We have determined the time course of transgene expression in the heart graft. This constitutes important information about ex vivo gene therapy for heart grafts.

Adenoviridae↗