ognizant Communication Corporation

Cell Transplantation, Vol. 16, pp. 355-364, 2007
0963-6897/07 $90.00 + 00
E-ISSN 1555-3892
Copyright © 2007 Cognizant Comm. Corp.
Printed in the USA. All rights reserved.

¹Brain Disease Research Center, Ajou University School of Medicine, Suwon, 443-721, Republic of Korea
²Division of Neurology, Department of Medicine, UBC Hospital, University of British Columbia, Vancouver, BC, Canada

Traumatic injuries to the spinal cord lead to severe and permanent neurological deficits. Although no effective therapeutic option is currently available, recent animal studies have shown that cellular transplantation strategies hold promise to enhance functional recovery after spinal cord injury (SCI). This review is to analyze the experiments where transplantation of stem/progenitor cells produced successful functional outcome in animal models of SCI. There is no consensus yet on what kind of stem/progenitor cells is an ideal source for cellular grafts. Three kinds of stem/progenitor cells have been utilized in cell therapy in animal models of SCI: embryonic stem cells, bone marrow mesenchymal stem cells, and neural stem cells. Neural stem cells or fate-restricted neuronal or glial progenitor cells were preferably used because they have clear capacity to become neurons or glial cells after transplantation into the injured spinal cord. At least a part of functional deficits after SCI is attributable to chronic progressive demyelination. Therefore, several studies transplanted glial-restricted progenitors or oligodendrocyte precursors to target the demyelination process. Directed differentiation of stem/progenitor cells to oligodendrocyte lineage prior to transplantation or modulation of microenvironment in the injured spinal cord to promote oligodendroglial differentiation seems to be an effective strategy to increase the extent of remyelination. Transplanted stem/progenitor cells can also contribute to promoting axonal regeneration by functioning as cellular scaffolds for growing axons. Combinatorial approaches using polymer scaffolds to fill the lesion cavity or introducing regeneration-promoting genes will greatly increase the efficacy of cellular transplantation strategies for SCI.

Key words: Spinal cord injury; Transplantation; Neural stem cell; Regeneration; Demyelination

Address correspondence to Seung U. Kim, Brain Disease Research Center, Ajou University School of Medicine, Suwon, Korea. Tel: 031-219-4500; Fax: 031-216-6381; E-mail: sukim@ajou.ac.kr

Department of Medical Bioregulation, Division of Cardiovascular Surgery and Medicine, Yamaguchi University School of Medicine, Ube, Yamaguchi 755-8505, Japan

Although cell therapy shows great promise as a new therapeutic strategy for heart failure, its precise mechanisms remain unclear. Furthermore, the advantages of cell therapy over conventional cytokine therapy have yet to be clarified. This study was designed to compare the functional improvement achieved by cell therapy and cytokine therapy in both ischemic and nonischemic heart failure experimental models. Ischemic heart failure was induced by ligating the left anterior descending artery, and nonischemic heart failure was induced by an IP injection of doxorubicin, respectively, in mice. After establishing the heart failure models, mice were randomly given a single intramyocardial injection of 2 x 10⁵ c-kit-positive bone marrow stem cells (cell therapy), hepatic growth factor (cytokine therapy), or PBS injection only (control). In the ischemic heart failure model, both cell therapy and cytokine therapy increased the vessel density significantly, inhibited apoptosis of myocytes, and decreased the fibrotic area in the ischemic myocardium, which resulted in a significant increase in the survival rate and enhancement of the cardiac function of these mice (p < 0.05 vs. control therapy). In the nonischemic heart failure model, significant increases in the survival rate and cardiac function were achieved by cell therapy (p < 0.05 vs. control therapy), but not by cytokine therapy, although cytokine therapy inhibited the fibrosis and apoptosis of the cardiomyocytes. Both cell therapy and cytokine therapy are alternative treatments for ischemic heart failure. However, cell therapy is more effective for the treatment of nonischemic heart failure than cytokine therapy achieved by the administration of a single growth factor.

Key words: Cell therapy; Cytokine therapy; Heart failure; Ischemia; Angiogenesis

Address correspondence to Tao-Sheng Li, M.D., Ph.D., Department of Surgery and Clinical Science, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube, Yamaguchi 755-8505, Japan. Tel: +81-836-222260; Fax: +81-836-222423; E-mail: litaoshe@yamaguchi-u.ac.jp

¹Obesity Research Center, St. Luke's Hospital, New York, NY, USA
²Department of Medicine, Columbia University, New York, NY, USA
³Cornell University, Ithaca, NY, USA
⁴Department of Pathology, Roosevelt Hospital, New York, NY, USA

White adipose tissue (WAT) transplantation, although widely used in humans, has been done for cosmetic and reconstructive purposes only. Accumulating evidence indicates, however, that WAT is an important endocrine organ and, therefore, WAT transplantation may become valuable as a replacement therapy for a number of hereditary human diseases. Because the most readily available source for such transplantations would be allogeneic tissue, the mechanisms involved in the rejection of WAT allograft should be explored. We have established a model in which leptin-producing allogeneic WAT is transplanted into leptin-deficient ob/ob mice. Because ob/ob mice are obese, hyperphagic, and hypothermic, WAT allograft function is monitored as the reversal of this leptin-deficient phenotype. Here we report that allografted WAT is primarily nonfunctional. However, when WAT is transplanted into immunodeficient (Rag1-/-) ob/ob mice, or into ob/ob mice depleted of T cells by anti-CD3 antibody, a long-term graft survival is achieved as indicated by the reversal of hyperphagia, weight loss, and normalization of body temperature. The symptoms of leptin deficiency rapidly recur when normal spleen cells of the recipient type are injected, or when the antibody treatment is terminated. In contrast, selective depletion of either CD4+ or CD8+ cells alone does not prevent WAT allograft rejection. Similarly, WAT allografts that do not express MHC class I or class II molecules are rapidly rejected, suggesting that both CD4+ and CD8+ T cells may independently mediate WAT allograft rejection.

Key words: White adipose tissue; Allograft; Rejection; T cells

Address correspondence to Vitaly Ablamunits, Ph.D., Obesity Research Center, St. Luke's Hospital, 1111 Amsterdam Avenue, Room #WH1020, New York, NY 10025, USA. Tel: 917-209-5429; Fax: 212-523-1632; E-mail: ablamunits@excite.com

Unité de Génétique Humaine, Centre de Recherche du CHUL, Université Laval, Québec, Canada

Human muscle precursor cell (hMPC) transplantation is a potential therapy for severe muscle trauma or myopathies. Some previous studies demonstrated that 1,25-dihydroxyvitamin-D₃ (1,25-D₃) acted directly on myoblasts, regulating their proliferation and fusion. 1,25-D₃ is also involved in apoptosis modulation of other cell types and may thus contribute to protect the transplanted hMPCs. We have therefore investigated whether 1,25-D₃ could improve the hMPC graft success. The 1,25-D₃ effects on hMPC proliferation, fusion, and survival were initially monitored in vitro. hMPCs were also grafted in the tibialis anterior of SCID mice treated or not with 1,25-D₃ to determine its in vivo effect. Graft success, proliferation, and viability of transplanted hMPCs were evaluated. 1,25-D₃ enhanced proliferation and fusion of hMPCs in vitro and in vivo. However, 1,25-D₃ did not protect hMPCs from various proapoptotic factors (in vitro) or during the early posttransplantation period. 1,25-D₃ enhanced hMPC graft success because the number of muscle fibers expressing human dystrophin was significantly increased in the TA sections of 1,25-D₃-treated mice (166.75 ± 20.64) compared to the control mice (97.5 ± 16.58). This result could be partly attributed to the improvement of the proliferation and differentiation of hMPCs in the presence of 1,25-D₃. Thus, 1,25-D₃ administration could improve the clinical potential of hMPC transplantation currently developed for muscle trauma or myopathies.

Key words: Human muscle precursor cell; Transplantation; Graft success; 1,25-Dihydroxyvitamin D₃

Address correspondence to Jacques P. Tremblay, Ph.D., Université Laval, Unité de Génétique humaine, Centre Hospitalier de l'Université Laval, 2705 boul. Laurier, RC-9300, Ste-Foy (Qc) Canada G1V 4G2. Tel: 418-654-2186 or 418-656-4141, ext. 7307; Fax: 418-654-2207; E-mail: Jacques-P.Tremblay@crchul.ulaval.ca

¹Department of Radiology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
²The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
³Department of Chemical Engineering, Johns Hopkins University, Baltimore, MD, USA

Several molecular therapies require the implantation of cells that secrete biotherapeutic molecules and imaging the location and microenvironment of the cellular implant to ascertain its function. We demonstrate noninvasive in vivo magnetic resonance imaging (MRI) of self-assembled microcontainers that are capable of cell encapsulation. Negative contrast was obtained to discern the microcontainer with MRI; positive contrast was obtained in the complete absence of background signal. MRI on a clinical scanner highlights the translational nature of this research. The microcontainers were loaded with cells that were dispersed in an extracellular matrix, and implanted both subcutaneously and in human tumor xenografts in SCID mice. MRI was performed on the implants, and microcontainers retrieved postimplantation showed cell viability both within and proximal to the implant. The microcontainers are characterized by their small size, three dimensionality, controlled porosity, ease of parallel fabrication, chemical and mechanical stability, and noninvasive traceability in vivo.

Key words: Cell therapy; Cell encapsulation; Magnetic resonance microscopy; Self-assembly; Microcapsules; Implantation

Address correspondence to Barjor Gimi, Department of Radiology, Children's Medical Center Dallas, University of Texas Southwestern Medical Center at Dallas, 1935 Motor Street, F1521, Dallas, TX 75062, USA. Tel: (214) 456-8776; Fax: (214) 456-6015; E-mail: barjorg@yahoo.com

¹Laboratory of Paediatric Hepatology and Cell Therapy, Université catholique de Louvain and Cliniques St Luc, Brussels, Belgium
²Hormone and Metabolic Research Unit, School of Medicine, Université catholique de Louvain and Institute of Cellular Pathology, Brussels, Belgium

Transplantation of human hepatocytes has recently been demonstrated as a safe alternative to partially correct liver inborn errors of metabolism. Cryopreservation remains the most appropriate way of cell banking. However, mitochondrial-mediated apoptosis has been reported after cryopreservation and little is known on the involved molecular mechanisms. The aim of this study was to investigate mitochondrial functions of freshly isolated and cryopreserved/thawed hepatocytes from mice and humans. We report here that cryopreservation induced a dramatic drop of ATP levels in hepatocytes. The oxygen consumption rate of cryopreserved/thawed hepatocytes was significantly lower compared to fresh cells. In addition, the uncoupling effect of 2,4-dinitrophenol was lost, in parallel with a reduction of mitochondrial membrane potential. Furthermore, a decrease in mitochondrial respiratory rate was evidenced on permeabilized hepatocytes in the presence of substrate for the respiratory chain complex 1. Interestingly, this effect was less marked with a substrate for complex 2. Electron microscopy examination indicated that mitochondria were swollen and devoid of cristae after cryopreservation. These changes could explain the cytosolic release of the proapoptotic protein cytochrome c in cryopreserved cells. Nevertheless, no caspase 9-3 activation and only few apoptotic and necrotic cells were found, indicating that the subsequent cell death program was not yet evidenced. Our results demonstrate that cryopreservation of hepatocytes induced alteration of the mitochondrial machinery. They also suggest that, in addition to technical progress in the cryopreservation procedure, protection of the respiratory chain complex 1 should be considered to improve the quality of cryopreserved hepatocytes.

Key words: Hepatocyte; Cryopreservation; Liver cell transplantation; Mitochondria; Complex

Address correspondence to Pr. Etienne M. Sokal, Paediatric Hepatology and Cell Therapy, Université Catholique de Louvain, Cliniques St Luc, 10 av. Hippocrate, B-1200 Bruxelles, Belgium. Tel: +32 (0) 2 764 1387; Fax: +32 (0) 2 764 8909; E-mail: etienne.sokal@uclouvain.be

*These authors contributed equally and must be considered as joined last authors.

¹Department of Bioengineering, Hanyang University, Seoul 133-791, Korea
²School of Chemical and Biological Engineering, Seoul National University, Seoul 151-742, Korea
³Department of Pathology, College of Medicine, Hanyang University, Seoul 133-791, Korea
⁴Department of Plastic Surgery, Catholic University College of Medicine, Seoul 137-701, Korea

Engineered adipose tissue can be used in plastic and reconstructive surgery to augment soft tissue lost due to mastectomy or lumpectomy. The three-dimensional space provided by a scaffold capable of withstanding in vivo compressive forces and neovascularization may promote engineered adipose tissue formation. The objective of this study was to determine whether voluminous adipose tissue can be engineered by combining a mechanically stable environment with basic fibroblast growth factor (bFGF). Mechanical support structures, fabricated from biodegradable synthetic polymers, were placed into subcutaneous pockets of athymic mice. Human preadipocytes, containing fibrin matrix, with (group 1) or without (group 2) bFGF were injected into the space created by the support structures. Additionally, human preadipocytes containing fibrin matrix, with (group 3) or without (group 4) bFGF, were injected into subcutaneous spaces without support structures. Six weeks after implantation, the original implant volume was approximately maintained in groups 1 and 2, whereas groups 3 and 4 showed significant implant shrinkage. Adipogenesis and angiogenesis were more extensive in the group 1 than any other group. The fraction of human nuclear antigen-positive adipocytes in the implant was highest in group 1. Mouse adipocyte-specific genes were also expressed in the implants, again at the highest levels in group 1. Implanted preadipocyte apoptosis was significantly reduced in the groups treated with bFGF (groups 1 and 3) as opposed to those without (groups 2 and 4). This study demonstrates that combining a mechanically stable environment with bFGF can promote voluminous adipose tissue regeneration. This adipogenesis was likely promoted by the mechanically stable three-dimensional space, enhanced neovascularization, implanted cell survival, and host adipogenic cell migration. The method described in this study could be useful to augment adipose tissue used in plastic and reconstructive surgery.

Key words: Engineered adipose tissue; Preadipocyte; Mechanical support structure; Mechanically stable environment; Basic fibroblast growth factor; Neovascularization

Address correspondence to Byung-Soo Kim, Department of Bioengineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791, Korea. Tel: +82-2-2220-0491; Fax: +82-2-2291-0838; E-mail: bskim@hanyang.ac.kr

LCT BioPharma, Inc., Providence, RI, USA

Delivery of neurotrophic molecules to the CNS is a potential treatment for preventing the neuronal loss in neurological disorders such as Huntington's disease (HD). Choroid plexus (CP) epithelial cell transplants secrete several neurotrophic factors and are neuroprotective in rat and monkey animal models of HD. HD patients receiving CP transplants would likely receive a course of immunosuppressant/anti-inflammatory treatment postsurgery and would remain on psychoactive medications to treat their motor, psychiatric, and emotional symptoms. Therefore, we examined whether CP epithelial cells are impacted by incubation with cyclosporine A (CsA), dexmethasone, haloperidol, fluoxetine, and carbamezapine. In each case, DNA was quantified to determine cell number, a formazen dye-based assay was used to quantify cell metabolism, and vascular endothelial growth factor (VEGF) levels were measured as a marker of protein secretion. Except for the highest dose of fluoxetine, none of the drugs tested exerted any detrimental effect on cell number. Incubation with CsA or dexamethasone did not have any consistent significant effect on VEGF secretion or cell metabolism. Carbamazepine was without effect while only the highest dose of haloperidol tested modestly lowered cell metabolism. VEGF secretion and cell metabolism was not measurable from CP cells exposed to 100 mM fluoxetine. These data continue to support the potential use of CP transplants in HD.

Key words: Choroid plexus; Xenotransplant; Vascular endothelial growth factor (VEGF); Encapsulation

Address correspondence to Dwaine F. Emerich, 241 Anan Wade Rd., Glocester, RI 02857, USA. Tel: 401-499-6662; Fax: 401-823-0466; E-mail: ED3FJM@aol.com

¹Clinical Islet Transplant Program, University of Alberta and Capital Health Authority, Edmonton, Alberta, Canada
²Department of Surgery, University of Alberta, Edmonton, Alberta, Canada
³Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
⁴Department of Medicine, University of Alberta, Edmonton, Alberta, Canada

Islet transplants are emerging as a viable option for the treatment of type 1 diabetes mellitus. From 1989 to 1995 we conducted a series of simultaneous islet&ndash;kidney transplants in six uremic type 1 diabetic patients. We report two of these patients who have shown persistent islet graft function over many years. Two female patients with duration of diabetes of 27 and 37 years underwent simultaneous islet-kidney transplant under steroid- and cyclosporine-based immunosuppression. Freshly isolated islets were supplemented with cryopreserved islets from our low-temperature bank of frozen islets. A total islet mass of 9,866 and 15,061 islet equivalents/kg body weight, respectively, was transplanted into the liver through portal vein. Reasonable blood glucose control has been achieved for up to 6 years posttransplant in one patient, but there was minimum clinical benefit from the islet graft at 10 years. In contrast, sustained insulin secretion with nearly normal HbA1c at 13 years follow-up was observed in another patient, providing hope for improving long-term graft outcomes for islet transplant recipient.

Key words: Islet transplantation; Type 1 diabetes; Immunosuppression; Long-term function; Simultaneous islet-kidney transplantation

Address correspondence to Jonathan R. T. Lakey, Ph.D., at his current address: CEO, Clinical Islet Transplantation Group Inc., Edmonton, Alberta, Canada T6G 2C8. Tel: (780) 407-8749; Fax: (780) 407-8760; E-mail: Jonlakey@rogers.blackberry.net