Peripheral blood microchimerism in female renal recipients from male donors

Microchimerism evaluation in recipients of living-related or unrelated deceased allograft renal transplants

The presence of microchimerism in the peripheral blood of solid organ graft recipients has been associated with long-term solid organ acceptance, immunologic tolerance, and less aggressive immunosuppressive therapy. Molecular biology assays are among the most sensitive methods to detect microchimerism, primarily to evaluate Y chromosome sequences in females as indirect evidence of circulating male nucleated donor cells. We screened for the presence of the SRY sequence region in peripheral blood of 13 female recipients of male kidney grafts: 5 living-related and 8 deceased grafts. Only patients who received grafts from related living donors exhibited microchimerism. Five of 13 patients studied exhibited better graft outcomes, including the 4 who were positive for the SRY sequences.

Myocyte growth in the failing heart

Adult ventricular myocytes can undergo mitotic division, resulting in an increase in the aggregate number of cells in the heart. The improvement in the methodological approach to the analysis of tissue sections by immunostaining and confocal microscopy has defeated the dogma that myocyte regeneration cannot occur in the adult heart. Most importantly, primitive and progenitor cells have been identified in the human heart. These cells express telomerase and have the capability of undergoing lineage commitment and rapid cell division, expanding significantly the contracting ventricular myocardium. These cell populations possess all the molecular components regulating the entry and progression through the cell cycle, karyokinesis, and cytokinesis. The recognition that myocyte hypertrophy and regeneration, as well as myocyte necrosis and apoptosis, occur in cardiac diseases has contributed to enhancing our understanding of the plasticity of the human heart.