Naoki Minato

Phenotypic modulation and turnover of bone marrow-derived cells after myocardial infarction in rats

BACKGROUND Bone marrow-derived cells (BMCs) are critically involved in inflammation and regeneration after myocardial infarction (MI). However, the participation of BMCs in the reconstruction of infarcted myocardium remains unclear. In this study, we investigated phenotypic modulation of BMCs and their turnover in the heart following MI. METHODS AND RESULTS MI was produced in rats with intra-bone marrow-bone marrow transplantation from the syngenic rats expressing green fluorescence protein (GFP). The number of GFP-positive BMCs recruited to the infarcted myocardium peaked at 3 days after MI, and the majority of BMCs recruited to the heart after MI underwent turnover within 2 weeks. This turnover rate was unchanged for up to 16 weeks after MI, although the number of BMCs recruited to the infarcted myocardium rapidly decreased between 2 and 8 weeks after MI. A small number of BMCs recruited to the heart were positive for CD31 and α-smooth muscle actin, and the majority of these were positive for vimentin at 3 days and 4 weeks after MI. None of BMCs expressed α-actinin or von Willebrand factor 4 weeks after MI. CONCLUSIONS These results suggest that BMCs recruited to the heart underwent phenotypic modulation to a fibroblastic cell type and turnover within 2 weeks after MI without differentiating into cardiomyocytes or endothelial cells, and that although the number of BMCs in the infarcted myocardium decreased over time, the rate of turnover remained relatively constant during the chronic phase of MI.

Complete removal of heart-compressing large mediastinal lipoma : a case report

An 83-year-old man presented with worsening of respiratory discomfort and underwent close examination, which revealed a large mediastinal lipoma measuring 15 × 10 cm. The patient showed heart failure symptoms due to heart compression by tumor. The tumor was completely removed safely and reliably by cutting the ascending aorta, main pulmonary artery and superior vena cava. Although preoperative examination could not determine whether the tumor was lipoma or liposarcoma, we selected an invasive surgical therapy because neither radiation therapy nor chemotherapy was considered effective for either type of tumor. We report here a very rare case of heart-compressing mediastinal tumor.

Life-saving strategy for left ventricular free wall rupture after acute myocardial infarction

OBJECTIVE Left ventricular free wall rupture after acute myocardial infarction is a serious complication with high mortality. For life-saving, it is important how to maintain poor hemodynamics till operation. We have consistently made it our strategy to attach percutaneous cardiopulmonary support system and intra-aortic balloon pumping immediately after the diagnosis regardless of the type of left ventricular free wall rupture and of the hemodynamic conditions, and perform an infarction-covering repair under the beating heart. We have studied the short-term and middle-term results after the operations, and have evaluated the efficacy and problems of this procedure. METHODS Since September 1994, we have performed this method in six of eight patients with left ventricular free wall rupture. RESULTS As results, five of the six patients (83%) were saved including two cases of blow-out type. Our strategy for left ventricular free wall rupture showed several advantages for preoperative and intraoperative maintenance of the hemodynamic conditions, and for preservation of some reversible myocardium by the simple technique of infarction-covering repair under the beating heart. These resulted in shortening the operation time, decreasing the incidence of low cardiac output syndrome, and obtaining a satisfactory rate of life-saving. CONCLUSION We believe that this infarction-covering repair based on our strategy is effective for life-saving during the acute period.

Heparin Induces the Mobilization of Heart-Derived Multipotent Mesoangioblasts During Cardiac Surgery With Cardiopulmonary Bypass or Cardiac Catheterization

BACKGROUND We previously identified circulating mesoangioblasts (cMABs), a subset of mesenchymal stem cells that express cardiac mesodermal markers, in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). We also found that hepatocyte growth factor (HGF) is upregulated during cardiac surgery with CPB in humans, and induces MAB-like cell mobilization in rodents. These results strongly suggest that heparin induced MAB mobilization via HGF upregulation. Here, we tested this hypothesis in patients undergoing cardiac surgery or cardiac catheterization. We also examined whether human cMABs are derived from the heart.Methods and Results:Plasma HGF levels were determined by ELISA. Mononuclear cells isolated from blood samples were cultured on fibronectin-coated dishes, and outgrowing cMAB colonies were counted. We first confirmed that HGF upregulation and cMAB mobilization were observed before the start of CPB, excluding the possibility that CPB is the primary inducer of cMAB mobilization. We then examined patients undergoing cardiac catheterization and found that heparin significantly increased plasma HGF levels and the number of cMAB colonies in a dose-dependent manner. The results of simultaneous blood sampling from the aortic sinus, coronary sinus, and right atrium were consistent with the notion that human cMABs are derived from the heart. CONCLUSIONS Human cMABs are mobilized by heparin injection during cardiac surgery or cardiac catheterization, presumably via HGF upregulation.

Traumatic ventricular septal rupture associated with rapid progression of heart failure despite low Qp/Qs ratio: a case report

BackgroundVentricular septal rupture (VSR) secondary to blunt chest trauma is rare and associated with a diverse range of symptoms and clinical courses as well as disease severity. We present a case of traumatic VSR in which rapid progression of heart failure was observed in spite of relatively low pulmonary to systemic blood flow (Qp/Qs) ratio.Case presentationA 40-year-old male was transported to the emergency department approximately 12 h after blunt chest trauma. VSR was diagnosed by echocardiography, and right heart catheterization revealed a Qp/Qs ratio of 1.52. Although medical treatment was initially attempted, subsequent rapid progression of heart failure necessitated emergent surgical repair of VSR.ConclusionsBecause small, asymptomatic VSR often close spontaneously, surgical repair of traumatic VSR is indicated when the shunt rate is relatively large or heart failure is present. However, the present case highlights the need to consider emergent surgical repair of traumatic VSR, even when the shunt rate is relatively small.

Skeletonized gastroepiploic artery: How we do it

The use of the gastroepiploic artery as a conduit for coronary artery bypass surgery has not been widely accepted due to unjustified reservations about the technical complexity, perioperative complications, and patency rate. As a result, even today, most patients with coronary artery disease do not receive complete arterial revascularization. Figure 1 illustrates the stages in our state-of-the-art harvesting technique for skeletonized gastroepiploic artery.

Autologous Adventitial Overlay Method Reinforces Anastomoses in Aortic Surgery

In this study, we present an inexpensive and effective method for providing a secure and hemostatic anastomosis using autologous adventitia obtained from a dissected or aneurysmal wall. The resected aortic wall is separated between the adventitia and media, and a soft, 2 × 10-cm adventitial strip is overlaid to cover the anastomotic margin. A graft is sutured to the aortic stump. This autologous adventitial overlay method can inexpensively and strongly reinforce the anastomosis during aortic surgery for dissection or aneurysm and will contribute to anastomotic hemostasis and long-term stability.

The case of successful catheter ablation using only the approach from the upper part of the subject's body, with meandering aorta and implanted IVC filter

A 79-year-old female had paroxysmal supraventricular tachycardia. However, she was implanted with an inferior vena cava filter and her descending aorta had significant meandering. It was thought that the insertion of the catheters would be difficult from the femoral vessels. Therefore we inserted electrode catheters from the right subclavian vein and internal jugular vein. As a result of an electrophysiology study, we diagnosed atrioventricular reciprocating tachycardia with a left lateral concealed accessory pathway (AP). An ablation catheter was introduced retrogradely through the left brachial artery and it was pushed forward under the mitral valve. Furthermore, it was put into the part where the earliest retrograde atrial deflection was recorded under the right ventricular apex pacing, and we succeeded in ablation of the AP. All catheters were inserted only from the upper part of the persons body. As for catheter operability, electric potential, operation time, and fluoroscopy time, there was no change in the case of either approach from the femoral vessels. Because we did not puncture the inguinal region, the patient was able to return to her ward on foot after the operation. In addition, we were able to perform a radical cure without complications.