Masayoshi Nagatsu

Comparative Study of Regulatory T Cell Function of Human CD25+CD4+ T Cells from Thymocytes, Cord Blood, and Adult Peripheral Blood

CD25+CD4+ regulatory T cells suppress T cell activation and regulate multiple immune reactions in in vitro and in vivo studies. To define the regulatory function of human CD25+CD4+ T cells at various stages of maturity, we investigated in detail the functional differences of CD25+CD4+ T cells from thymocytes, cord blood (CB), and adult peripheral blood (APB). CB CD25+CD4+ T cells displayed low-FOXP3 protein expression level and had no suppressive activity. In contrast, CD25+CD4+ T cells from thymocytes or APB expressed high expression level of FOXP3 protein associated with significant suppressive activity. Although CB CD25+CD4+ T cells exhibited no suppressive activity, striking suppressive activity was observed following expansion in culture associated with increased FOXP3 expression and a shift from the CD45RA+ to the CD45RA− phenotype. These functional differences in CD25+CD4+ T cells from Thy, CB, and APB hence suggest a pathway of maturation for Treg in the peripheral immune system.

Extracardiac total cavopulmonary connection using a tissue-engineered graft

OBJECTIVE Extracardiac and lateral tunnel total cavopulmonary connection are currently 2 major options for patients with a single ventricle physiology. However, each procedure has some disadvantages over the other. We developed a new technique of extracardiac total cavopulmonary connection using a tissue-engineered graft to overcome some of the disadvantages previously associated with both the extracardiac and lateral tunnel procedures. METHODS Between February 2001 and October 2002, 8 patients underwent an extracardiac total cavopulmonary connection using a tissue-engineered graft in our institution. Collected bone marrow cells (1 x 10(8) mononucleocytes) from a patient (approximately 1-4 mL/kg body weight) were seeded onto a biodegradable scaffold composed of polycaprolactone-polylactic acid copolymer reinforced with woven polylactic acid. After a 2- to 4-hour cultivation, the seeded scaffold was implanted as an extracardiac conduit during the total cavopulmonary connection operation. RESULTS There were no hospital or late deaths. At a mean follow-up of 13.4 months (range 4-25 months), all patients are alive and asymptomatic with no need for repeat surgery. A postoperative catheter examination or computed tomography showed all tissue-engineered grafts to be patent and revealed no stenosis, obstruction, or aneurysmal change in the 8 patients. CONCLUSION We believe that extracardiac total cavopulmonary connection using a tissue-engineered graft has the potential to overcome some of the disadvantages previously associated with extracardiac or lateral tunnel total cavopulmonary connection. However, an extended follow-up period is required to clarify the long-term clinical outcome for the tissue-engineered graft.

Origin of the left coronary artery from the right pulmonary artery

We report the successful surgical treatment of a 12-year-old boy with a rare type of Bland-White-Garland syndrome with mitral regurgitation, in which an anomalous left coronary artery arose from the middle portion of the right pulmonary artery, employing the direct translocation of the left coronary artery and mitral valvuloplasty.