Mitochondrial transfer between cells: Methodological constraints in cell culture and animal models.

Interest in the recently discovered phenomenon of mitochondrial transfer between mammalian cells has gained momentum since it was first described in cell culture systems more than a decade ago. Mitochondria-targeting fluorescent dyes have been repurposed and are now widely used in these studies and in acute disease models, sometimes without due consideration of their limitations, while vectors containing mitochondrially-imported fluorescent proteins have complemented the use of mitochondria-targeting dyes. Genetic approaches that use mitochondrial DNA polymorphisms have also been used in some in vitro studies and in tumor models and are particularly useful where mtDNA is damaged or deleted. These approaches can also be used to study the long-term consequences of mitochondrial transfer such as in bone marrow and organ transplantation and in tumour biology where inherent mitochondrial damage is often a key feature. As research on intercellular mitochondrial transfer moves from cell culture into animal models and human diseases it will be important to understand the limitations of the various techniques in order to apply appropriate methodologies to address physiological and pathophysiological conditions.

Transplantation of the small bowel across MHC and non-MHC disparities in the rat.

Using congenic strains of rats, the effect on the rejection of small bowel transplants across isolated major histocompatibility complex (MHC) and nonMHC antigenic disparities was examined. The medial survival time of small bowel grafts across MHC differences in the LEW anti-LEW.1N and LEW.1N anti-LEW strain combinations was 14 and 12 days, respectively. The median survival time across the nonMHC antigenic difference in the BN anti-DA.1N strain combination was 20 days, which was significantly longer than the rejection time across the MHC differences (P less than 0.005). Both hemagglutinating and cytotoxic antibodies were produced in all three strain combinations, but the magnitude of the response varied considerably and did not correlate with the time of rejection. In the case of MHC differences, the antibody was directed against both class I and class II antigens, and with the nonMHC difference, the greatest response was directed against the major blood group antigen RT2.