Akiko Makiuchi

Suppression of acute and chronic rejection by hepatocyte growth factor in a murine model of cardiac transplantation: Induction of tolerance and prevention of cardiac allograft vasculopathy

Background—Although treatment with immunosuppressive agents has contributed to overcoming acute rejection and improving the midterm survival of transplanted hearts, cardiac allograft vasculopathy (CAV) has remained the main cause of primary graft failure. Recent approaches have shown that hepatocyte growth factor (HGF) exhibits cardiotrophic functions. We therefore addressed whether HGF would regulate acute and chronic rejection in cardiac transplantation. Methods and Results—We used a murine heterotopic cardiac transplantation model between fully incompatible strains and administered 500 &mgr;g · kg−1 · d−1 HGF during the initial 14 days after transplantation. The HGF-treated allografts showed significantly prolonged survival (42.3±4.1 days, P<0.001) compared with the controls (11.1±0.6 days), with tolerance induction in 47.4%. Histopathologically, the number of infiltrating cells was significantly decreased and myocardial necrosis was less prominent with a reduction of apoptosis in the allografts by HGF treatment during acute rejection. In the long-term surviving allografts, HGF significantly inhibited the development of CAV and interstitial fibrosis. With respect to intragraft cytokine mRNA expression, HGF treatment reduced the early expression of interferon-&ggr; and enhanced the expression of transforming growth factor-&bgr;1 during the acute phase and of interleukin-10 continuously through the acute phase to the chronic phase. Conclusions—Our findings demonstrate that HGF can prolong the survival of allografts by its cardioprotective and immunomodulative potencies. Thus, HGF administration may constitute a new therapeutic approach to preventing cardiac graft failure that has not been overcome by conventional immunosuppressive agents.

A solitary fibrous tumor arising from the thymus

Solitary fibrous tumors (SFTs) are localized mesenchymal lesions which most frequently arise in the pleura but have also been observed in many other sites. SFTs arising from the thymus are relatively rare, however, and only a few cases have been reported to date. We report such a case in our current study.

Solitary aneurysm of the innominate vein.

Two cases of isolated saccular aneurysms of the innominate vein are presented that appeared as mediastinal masses. Contrast-enhanced computed tomography (CT) allowed for accurate diagnosis in one patient, while the second patient had atypical CT findings that led to thoracotomy for proper diagnosis. A diagnosis of innominate vein aneurysm should be considered when a uniform attenuation mediastinal mass is seen on CT so that unnecessary biopsy and surgery can be avoided.

Chest wall myxoma protruding into the thoracic cavity.

Myxoma protruding from the chest wall into the thoracic cavity is very rare. We report our experience in treating a 42-year-old man admitted for a painless mass on the anterior chest wall. Magnetic resonance imaging showed a sharply defined 5 x 4 x 4 cm mass protruding from the chest wall into the thoracic cavity, which we excised surgically. Histologically, the tumor proved to be a myxoma.