Shunji Sano

Monolayered mesenchymal stem cells repair scarred myocardium after myocardial infarction

Mesenchymal stem cells are multipotent cells that can differentiate into cardiomyocytes and vascular endothelial cells. Here we show, using cell sheet technology, that monolayered mesenchymal stem cells have multipotent and self-propagating properties after transplantation into infarcted rat hearts. We cultured adipose tissue–derived mesenchymal stem cells characterized by flow cytometry using temperature-responsive culture dishes. Four weeks after coronary ligation, we transplanted the monolayered mesenchymal stem cells onto the scarred myocardium. After transplantation, the engrafted sheet gradually grew to form a thick stratum that included newly formed vessels, undifferentiated cells and few cardiomyocytes. The mesenchymal stem cell sheet also acted through paracrine pathways to trigger angiogenesis. Unlike a fibroblast cell sheet, the monolayered mesenchymal stem cells reversed wall thinning in the scar area and improved cardiac function in rats with myocardial infarction. Thus, transplantation of monolayered mesenchymal stem cells may be a new therapeutic strategy for cardiac tissue regeneration.

Right ventricle–pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome

OBJECTIVE Pulmonary overcirculation through a systemic-pulmonary shunt has been one of the major causes of early death after the Norwood procedure. To avoid this lethal complication, we constructed a right ventricle-pulmonary shunt in first-stage palliation of hypoplastic left heart syndrome. METHODS Between February 1998 and February 2002, 19 consecutive infants, aged 6 to 57 days (median, 9 days) and weighing 1.6 to 3.9 kg (median, 3.0 kg), underwent a modified Norwood operation with the right ventricle-pulmonary artery shunt. The procedure included aortic reconstruction by direct anastomosis of the proximal main pulmonary artery and a nonvalved polytetrafluoroethylene shunt between a small right ventriculotomy and a distal stump of the main pulmonary artery. The size of the shunt used was 4 mm in 5 patients and 5 mm in 14. RESULTS All patients were managed without any particular manipulation to control pulmonary vascular resistance. There were 17 survivors (89%), including 3 patients weighing less than 2 kg. Two late deaths occurred due to obstruction of the right ventricle-pulmonary artery shunt. Thirteen patients underwent a stage II Glenn procedure after a mean interval of 6 months, with 2 hospital deaths. To date, a stage III Fontan procedure has been completed in 4 patients. Overall survival was 62% (13/19). Right ventricular fractional shortening at the last follow-up (3-48 months after stage I) ranged from 26% to 43% (n = 13, mean, 33%). CONCLUSION Without delicate postoperative management to control pulmonary vascular resistance, the modified Norwood procedure using the right ventricle-pulmonary shunt provides a stable systemic circulation as well as adequate pulmonary blood flow. This novel operation may be particularly beneficial to low-birth-weight infants with hypoplastic left heart syndrome.

Risk Factors for Mortality After the Norwood Procedure Using Right Ventricle to Pulmonary Artery Shunt

BACKGROUND The purpose of this study was to describe the experience with staged surgical reconstruction of the hypoplastic left heart syndrome (HLHS) with a right ventricle to pulmonary artery conduit and to identify the risk factors that influence late outcome. METHODS Between February 1998 and June 2007, 62 patients with HLHS underwent a Norwood procedure by using right ventricle to pulmonary artery conduit (median age, 9 days [range, 1 to 57]; median body weight 2.7 kg [range, 1.6 to 3.9 kg]). The subsequent 47 patients underwent a bidirectional Glenn procedure (stage 2). Thirty-two patients underwent a modified Fontan procedure (stage 3). Follow-up was complete (median, 32 months; range, 1 to 101). RESULTS Hospital mortality after the Norwood procedure was 8% (5 of 62 patients). Between stages, 9 patients died, 3 before stage 2 and 6 before stage 3. There was 1 late death after stage 3. Overall survival was 76% (47 of 62). The estimated 1-year and and 5-year survival rates were 80% and 73%, respectively. Using the any-mortality as the endpoint, prematurity (gestational age <37 weeks), body weight less than 2.5 kg at stage 1 operation, and tricuspid regurgitation 2+ or more were associated with mortality. Using Cox regression analysis, body weight less than 2.5 kg and tricuspid regurgitation 2+ or more were two independent factors associated with midterm survival. CONCLUSIONS From 9 years of experience, despite good early survival after Norwood stage 1 palliation, low body weight and tricuspid valve regurgitation were still associated with worse outcome. More efforts should be made to improve the late results for patients with hypoplastic left heart syndrome.

Adrenomedullin gene transfer induces therapeutic angiogenesis in a rabbit model of chronic hind limb ischemia : benefits of a novel nonviral vector, gelatin

Background—Earlier studies have shown that adrenomedullin (AM), a potent vasodilator peptide, has a variety of cardiovascular effects. However, whether AM has angiogenic potential remains unknown. This study investigated whether AM gene transfer induces therapeutic angiogenesis in chronic hind limb ischemia. Methods and Results—Ischemia was induced in the hind limb of 21 Japanese White rabbits. Positively charged biodegradable gelatin was used to produce ionically linked DNA-gelatin complexes that could delay DNA degradation. Human AM DNA (naked AM group), AM DNA-gelatin complex (AM-gelatin group), or gelatin alone (control group) was injected into the ischemic thigh muscles. Four weeks after gene transfer, significant improvements in collateral formation and hind limb perfusion were observed in the naked AM group and AM-gelatin group compared with the control group (calf blood pressure ratio: 0.60±0.02, 0.72±0.03, 0.42±0.06, respectively). Interestingly, hind limb perfusion and capillary density of ischemic muscles were highest in the AM-gelatin group, which revealed the highest content of AM in the muscles among the three groups. As a result, necrosis of lower hind limb and thigh muscles was minimal in the AM-gelatin group. Conclusions—AM gene transfer induced therapeutic angiogenesis in a rabbit model of chronic hind limb ischemia. Furthermore, the use of biodegradable gelatin as a nonviral vector augmented AM expression and thereby enhanced the therapeutic effects of AM gene transfer. Thus, gelatin-mediated AM gene transfer may be a new therapeutic strategy for the treatment of peripheral vascular diseases.

Intracoronary Autologous Cardiac Progenitor Cell Transfer in Patients With Hypoplastic Left Heart Syndrome The TICAP Prospective Phase 1 Controlled Trial

Rationale: Hypoplastic left heart syndrome (HLHS) remains a lethal congenital cardiac defect. Recent studies have suggested that intracoronary administration of autologous cardiosphere-derived cells (CDCs) may improve ventricular function. Objective: The aim of this study was to test whether intracoronary delivery of CDCs is feasible and safe in patients with hypoplastic left heart syndrome. Methods and Results: Between January 5, 2011, and January 16, 2012, 14 patients (1.8±1.5 years) were prospectively assigned to receive intracoronary infusion of autologous CDCs 33.4±8.1 days after staged procedures (n=7), followed by 7 controls with standard palliation alone. The primary end point was to assess the safety, and the secondary end point included the preliminary efficacy to verify the right ventricular ejection fraction improvements between baseline and 3 months. Manufacturing and intracoronary delivery of CDCs were feasible, and no serious adverse events were reported within the 18-month follow-up. Patients treated with CDCs showed right ventricular ejection fraction improvement from baseline to 3-month follow-up (46.9%±4.6% to 52.1%±2.4%; P=0.008). Compared with controls at 18 months, cardiac MRI analysis of CDC-treated patients showed a higher right ventricular ejection fraction (31.5%±6.8% versus 40.4%±7.6%; P=0.049), improved somatic growth (P=0.0005), reduced heart failure status (P=0.003), and lower incidence of coil occlusion for collaterals (P=0.007). Conclusions: Intracoronary infusion of autologous CDCs seems to be feasible and safe in children with hypoplastic left heart syndrome after staged surgery. Large phase 2 trials are warranted to examine the potential effects of cardiac function improvements and the long-term benefits of clinical outcomes. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01273857.

Application of Real-Time Three-Dimensional Transesophageal Echocardiography Using a Matrix Array Probe for Transcatheter Closure of Atrial Septal Defect

BACKGROUND The aim of this study was to demonstrate the utility of real-time three-dimensional (3D) transesophageal echocardiography (RT3D-TEE) using a matrix array 3D transesophageal echocardiographic probe for morphologic evaluation and guidance of transcatheter closure of atrial septal defects (ASDs). METHODS Forty-eight consecutive patients scheduled for the intervention were included. Two-dimensional (2D) transesophageal echocardiography (2D-TEE) and RT3D-TEE were performed before and during the procedures. Measurements of maximal ASD diameter and surrounding rims obtained on RT3D-TEE were compared with those obtained on 2D-TEE. RESULTS In 46 patients (96%), optimal 3D images for the morphologic evaluation of ASDs were obtained. RT3D-TEE facilitated the evaluation of ASD morphology and surrounding rims and was able to provide intraprocedural information clearly. A Bland-Altman plot showed a mean maximal diameter difference of -0.12 mm between the means (95% limits of agreement, -2.2 to 2.5 mm). CONCLUSION RT3D-TEE is a clinically useful, complementary option to 2D-TEE for evaluation of ASD morphology and for interventional guidance.

The improvement of care for paediatric and congenital cardiac disease across the World: a challenge for the World Society for Pediatric and Congenital Heart Surgery

The diagnosis and treatment for paediatric and congenital cardiac disease has undergone remarkable progress over the last 60 years. Unfortunately, this progress has been largely limited to the developed world. Yet every year approximately 90% of the more than 1,000,000 children who are born with congenital cardiac disease across the world receive either suboptimal care or are totally denied care.While in the developed world the focus has changed from an effort to decrease post-operative mortality to now improving quality of life and decreasing morbidity, which is the focus of this Supplement, the rest of the world still needs to develop basic access to congenital cardiac care. The World Society for Pediatric and Congenital Heart Surgery [http://www.wspchs.org/] was established in 2006. The Vision of the World Society is that every child born anywhere in the world with a congenital heart defect should have access to appropriate medical and surgical care. The Mission of the World Society is to promote the highest quality comprehensive care to all patients with pediatric and/or congenital heart disease, from the fetus to the adult, regardless of the patients economic means, with emphasis on excellence in education, research and community service.We present in this article an overview of the epidemiology of congenital cardiac disease, the current and future challenges to improve care in the developed and developing world, the impact of the globalization of cardiac surgery, and the role that the World Society should play. The World Society for Pediatric and Congenital Heart Surgery is in a unique position to influence and truly improve the global care of children and adults with congenital cardiac disease throughout the world [http://www.wspchs.org/].

Total Right Ventricular Exclusion Improves Left Ventricular Function in Patients With End-Stage Congestive Right Ventricular Failure

Background—We developed a total right ventricular (RV) exclusion procedure for the treatment of isolated congestive RV failure. The objective of the present study was to elucidate the effects of a complete removal of RV volume overload (RVVO) on the surgically created single left ventricle (LV). Methods and Results—Three adults (2 arrhythmogenic RV dysplasia, 1 Ebstein) and 5 children (all Ebstein) in NYHA class IV underwent the procedure. The RV free wall was resected from the heart, and the tricuspid orifice was closed. Pulmonary blood supply was obtained by a cavopulmonary connection in 6 patients and a systemic-pulmonary shunt in 2. The LV function was evaluated by 2-dimensional echocardiography 1 month after the surgery. All patients are alive. The paradoxical movement of the interventricular septum and geometry of the LV expressed by its eccentricity (2.1 to 1.2, P <0.01) were normalized after the operation in all 8 patients. LV end-diastolic volumes (59% to 109% of normal value, P <0.01), indexed maximal left atrial area (6.5 to 10.5 cm2/m2, P <0.01), LV ejection fraction (27% to 62%, P <0.01), and cardiac index (2.1 to 3.3 L/min/m2, P <0.05) all significantly increased. Conclusion—Removal of the RVVO by means of the total RV exclusion procedure provides effective volume loading, restores a cylindrical shape, and improves contractile function of the LV, thus leading to increased systemic output.

Single-stage repair of aortic coarctation with ventricular septal defect using isolated cerebral and myocardial perfusion

OBJECTIVE To avoid hypothermic circulatory arrest, we have repaired aortic coarctation with ventricular septal defect (VSD) in a one-stage procedure using an isolated cerebral and myocardial perfusion technique, and retrospectively compared this novel approach to the conventional two-stage approach. METHODS Between October 1991 and February 1999, 24 infants, aged 4-137 days (median, 27 days) and weighing 1.7-4.3 kg (median, 3.0 kg), underwent the repair of aortic coarctation with VSD either in one (group I, n=11) or two stages (group II, n=13). In Group I, an arterial cannula for cardiopulmonary bypass was inserted into the ascending aorta in six patients with coarctation only, or into a polytetrafluoroethylene (PTFE) graft which was anastomosed to the innominate artery in the remaining five who had hypoplastic arches. A cross-clamp was placed between the innominate and left carotid arteries. The bypass flow was reduced to 30-50% of full flow at 28 degrees C, thereby maintaining a radial artery pressure of 30-45 mmHg. At this point, the aortic coarctation was repaired by an end-to-end arch anastomosis, while maintaining brain perfusion and with the heart still beating. In five patients with hypoplastic aortic arches, the innominate artery proximal to the graft was then secured down and the arch anastomosis was extended to the distal ascending aorta, while providing isolated cerebral perfusion and cardioplegic arrest. After arch reconstruction was performed, the clamp was moved onto the ascending aorta, and the VSD was closed with systemic perfusion. In contrast, for group II patients, coarctation repairs were performed through a posterolateral approach, and existing VSDs were closed as secondary procedures. RESULTS The mean isolated cerebral and myocardial perfusion time for group I was 13 min (range, 7-20 min). The myocardial ischemic time did not differ between groups I and II (43+/-4 vs. 42+/-5 min, not significant). There were no hospital mortalities or neurological complications in either group, but one late death in each group. CONCLUSION Single-stage repair of aortic coarctation with VSD does not increase myocardial ischemic time compared to the traditional two-stage approach. The isolated cerebral and myocardial perfusion technique may offer substantial brain and myocardial protection during aortic arch reconstruction.

Atrial Natriuretic Peptide Protects Against Ischemia-Reperfusion Injury in the Isolated Rat Heart

BACKGROUND Atrial natriuretic peptide (ANP), a stimulator of particulate guanylate cyclase, has been found to protect against reoxygenation-induced hypercontracture in isolated cardiomyocytes by increasing cyclic guanosine monophosphate synthesis. The purpose of this study was to investigate the cardioprotective effects of ANP against ischemia-reperfusion injury in isolated rat hearts. METHODS Twenty-four hearts were perfused with ANP at 0.01, 0.1, and 1 micromol/L or without ANP (n = 6 each) in normoxic conditions. Because 0.1 micromol/L ANP induced a threefold increase in cyclic guanosine monophosphate release into the coronary effluent without any effect on cardiac function, we used the 0.1 micromol/L ANP dose for ischemia-reperfusion studies. Eighteen hearts were subjected to 15 minutes of normothermic global ischemia followed by 15 minutes of reperfusion. The hearts were divided into three groups (n = 6 each). RESULTS In group 1, ANP was added before ischemia. In group 2, ANP was added to the reperfusate. Hearts were untreated in the control group. In group 1, the postischemic recovery of cardiac output, coronary flow, and cyclic guanosine monophosphate release was similar to the control group. In group 2, the recovery of cardiac output was significantly better than the control group (82.1% +/- 9.8% vs 61.8% +/- 6.8%, respectively, p < 0.01) with a similar trend to recovery of coronary flow (90.7% +/- 8.5% vs 79.3% +/- 11.8%, respectively). The improved cardiac function was closely related to a significant increase in postischemic cyclic guanosine monophosphate release. CONCLUSIONS Administration of ANP at the time of reperfusion protects the myocardium from ischemia-reperfusion injury. The concentrations of administration must not only increase the release of cyclic guanosine monophosphate release, but also lack negative inotropic effects.