Long-term regeneration and remodeling of the pig esophagus after circumferential resection using a retrievable synthetic scaffold carrying autologous cells.

Treatment of esophageal disease can necessitate resection and reconstruction of the esophagus. Current reconstruction approaches are limited to utilization of an autologous conduit such as stomach, small bowel, or colon. A tissue engineered construct providing an alternative for esophageal replacement in circumferential, full thickness resection would have significant clinical applications. In the current study, we demonstrate that regeneration of esophageal tissue is feasible and reproducible in a large animal model using synthetic polyurethane electro-spun grafts seeded with autologous adipose-derived mesenchymal stem cells (aMSCs) and a disposable bioreactor. The scaffolds were not incorporated into the regrown esophageal tissue and were retrieved endoscopically. Animals underwent adipose tissue biopsy to harvest and expand autologous aMSCs for seeding on electro-spun polyurethane conduits in a bioreactor. Anesthetized pigs underwent full thickness circumferential resection of the mid-lower thoracic esophagus followed by implantation of the cell seeded scaffold. Results from these animals showed gradual structural regrowth of endogenous esophageal tissue, including squamous esophageal mucosa, submucosa, and smooth muscle layers with blood vessel formation. Scaffolds carrying autologous adipose-derived mesenchymal stem cells may provide an alternative to the use of a gastro-intestinal conduit for some patients following resection of the esophagus.

A novel monoclonal antibody inhibits the immune response of human cells against porcine cells: identification of a porcine antigen homologous to CD58.

BACKGROUND: Human CD58 is an adhesion molecule that interacts with CD2 on lymphocytes. We describe here an antibody that blocks responses of human peripheral blood mononuclear cells (PBMCs) to porcine cells and reacts with a porcine protein with homology to CD58. METHODS: Antibodies were isolated with a screen for inhibition of the human antiporcine response. One of these antibodies was used for immunoaffinity purification of a protein that was identified by molecular weight determination, endoglycosidase sensitivity, and microsequencing analysis as a porcine homologue of CD58. RESULTS: The antigen recognized by this antibody was a cell surface protein of relative molecular mass (Mr)=45,000 containing N-linked carbohydrate chains. Immunoaffinity purification of this protein and microsequencing revealed homology to sheep CD58 as well as sequences that were common to this protein and both sheep and human CD58. The protein was widely distributed on porcine cells, including lymphocytes, endothelial cells, muscle cells, and neuronal cells. This antibody efficiently inhibited lysis of porcine targets by human PBMCs in addition to preventing proliferation of the human PBMCs in response to the porcine cells. CONCLUSIONS: The CD2 interaction with porcine cells is important for the efficient recognition of porcine tissue, and inhibition of the human antiporcine immune response with the antibody is likely to be caused by the disruption of the human CD2 interaction with this porcine homologue of CD58. The antibody may prove to be useful for the blocking of this interaction without interfering with other functions of T cells.

Autologous skeletal myoblasts transplanted to ischemia-damaged myocardium in humans. Histological analysis of cell survival and differentiation.

OBJECTIVES: We report histological analysis of hearts from patients with end-stage heart disease who were transplanted with autologous skeletal myoblasts concurrent with left ventricular assist device (LVAD) implantation. BACKGROUND: Autologous skeletal myoblast transplantation is under investigation as a means to repair infarcted myocardium. To date, there is only indirect evidence to suggest survival of skeletal muscle in humans. METHODS: Five patients (all male; median age 60 years) with ischemic cardiomyopathy, refractory heart failure, and listed for heart transplantation underwent muscle biopsy from the quadriceps muscle. The muscle specimen was shipped to a cell isolation facility where myoblasts were isolated and grown. Patients received a transplant of 300 million cells concomitant with LVAD implantation. Four patients underwent LVAD explant after 68, 91, 141, and 191 days of LVAD support (three transplant, one LVAD death), respectively. One patient remains alive on LVAD support awaiting heart transplantation. RESULTS: Skeletal muscle cell survival and differentiation into mature myofibers were directly demonstrated in scarred myocardium from three of the four explanted hearts using an antibody against skeletal muscle-specific myosin heavy chain. An increase in small vessel formation was observed in one of three patients at the site of surviving myotubes, but not in adjacent tissue devoid of engrafted cells. CONCLUSIONS: These findings represent demonstration of autologous myoblast cell survival in human heart. The implanted skeletal myoblasts formed viable grafts in heavily scarred human myocardial tissue. These results establish the feasibility of myoblast transplants for myocardial repair in humans.

Modulation of the in vivo primate anti-Gal response through administration of anti-idiotypic antibodies.

Polyclonal anti-idiotypic antibodies (AIA) were generated against human Gal alpha 1,3Gal antibodies (anti-Gal) isolated from a single donor. Specificity of the AIA was demonstrated by selective binding to anti-Gal antibodies (Ab) and absence of reactivity to non-Gal Ab. The idiotopes identified by AIA were present on anti-Gal Ab from all of the human samples evaluated (n=59) as well as on pooled samples, demonstrating that a restricted number of dominant idiotopes characterized the human anti-Gal Ab response. Furthermore, the AIA had cross-species reactivity with baboon serum samples (n=19), suggesting that the overall shape of the anti-Gal Ab combining site is conserved throughout the Old World primates and providing additional evidence of the limited heterogeneity of the anti-Gal Ab repertoire. In order to evaluate the potential effect of AIA in the modulation of the anti-Gal response in vivo, a baboon was injected with repeated doses of the purified AIA. Following AIA treatment, new Ab were generated that reduced Ab-mediated cytotoxicity to porcine cells. Furthermore, administration of the AIA to a baboon prolonged the survival of intravenously infused pig hematopoietic cells when compared with their survival in a control baboon that did not receive prior AIA treatment but underwent a similar conditioning regimen.