Influence of aging on the quantity and quality of human cardiac stem cells

Advanced age affects various tissue-specific stem cells and decreases their regenerative ability. We therefore examined whether aging affected the quantity and quality of cardiac stem cells using cells obtained from 26 patients of various ages (from 2 to 83 years old). We collected fresh right atria and cultured cardiosphere-derived cells (CDCs), which are a type of cardiac stem cell. Then we investigated growth rate, senescence, DNA damage, and the growth factor production of CDCs. All samples yielded a sufficient number of CDCs for experiments and the cellular growth rate was not obviously associated with age. The expression of senescence-associated b-galactosidase and the DNA damage marker, gH2AX, showed a slightly higher trend in CDCs from older patients (≥65 years). The expression of VEGF, HGF, IGF-1, SDF-1, and TGF-b varied among samples, and the expression of these beneficial factors did not decrease with age. An in vitro angiogenesis assay also showed that the angiogenic potency of CDCs was not impaired, even in those from older patients. Our data suggest that the impact of age on the quantity and quality of CDCs is quite limited. These findings have important clinical implications for autologous stem cell transplantation in elderly patients.

Cardiosphere-derived cell sheet primed with hypoxia improves left ventricular function of chronically infarcted heart

Cardiosphere-derived cells (CDCs) isolated from postnatal heart tissue are a convenient and efficientresource for the treatment of myocardial infarction. However, poor retention of CDCs in infarcted hearts often causes less than ideal therapeutic outcomes. Cell sheet technology has been developed as a means of permitting longer retention of graft cells, and this therapeutic strategy has opened new avenues of cell-based therapy for severe ischemic diseases. However, there is still scope for improvement before this treatment can be routinely applied in clinical settings. In this study, we investigated whether hypoxic preconditioning enhances the therapeutic efficacy of CDC monolayer sheets. To induce hypoxia priming, CDC monolayer sheets were placed in an incubator adjusted to 2% oxygen for 24 hours, and then preconditioned mouse CDC sheets were implanted into the infarcted heart of old myocardial infarction mouse models. Hypoxic preconditioning of CDC sheets remarkably increased the expression of vascular endothelial growth factor through the PI3-kinase/Akt signaling pathway. Implantation of preconditioned CDC sheets improved left ventricular function inchronically infarcted hearts and reduced fibrosis. The therapeutic efficacy of preconditioned CDC sheets was higher than the CDC sheets that were cultured under normaxia condition. These results suggest that hypoxic preconditioning augments the therapeutic angiogenic and anti-fibrotic activity of CDC sheets. A combination of cell sheets and hypoxic preconditioning offers an attractive therapeutic protocol for CDC transplantation into chronically infarcted hearts.

[Aortic Arch-descending Aorta Bypass for Intraoperative Lower Body Malperfusion during Chronic Type A Aortic Dissection Repair]

We present a case of intraoperative lower body malperfusion in a 55-year-old woman who was undergoing total aortic arch replacement (TAR) for chronic type A aortic dissection. We planned 2-staged operation that consisted of total aortic arch replacement using the elephant trunk technique and thoracic endovascular aneurysm repair. During the 1st surgery, hemodynamic findings after TAR indicated lower body malperfusion, with the blood pressure of the upper body of 127/46 (68) mmHg and that of the lower body of 71/46 (51) mmHg. Transesophageal echocardiography showed narrowing of the true lumen and expansion of the false lumen of the proximal descending aorta. We performed aortic arch-descending aorta bypass using the branch for arterial return of the prosthetic arch graft. After the bypass procedure, lower body malperfusion improved. The postoperative course was uneventful. Extraanatomical aortic arch-descending aorta bypass may be an option for improving intraoperative malperfusion of the lower body due to true lumen narrowing.

[Radical nephrectomy and caval tumor thrombectomy with cardiopulmonary bypass combined with right anterior minithoracotomy;report of a case]

Renal cell carcinoma is a tumor with a distinct feature that it can invade the renal vein and grow intravascularly extending to the inferior vena cava (IVC). We herein report a case of a 71-year-old female who presented with a neoplasm that involved the right kidney and an intra-IVC tumor thrombus. We performed radical nephrectomy and tumor thrombectomy under cardiopulmonary bypass through a right anterior mini thoracotomy. The patient was discharged on the 13th day after the surgery without any complication, and is currently in good health at 7 months after the operation.

Mortality and morbidity after total aortic arch replacement

BACKGROUND

Total aortic arch replacement is associated with considerable mortality and morbidity. Although operative death is the most extreme adverse clinical end point, postoperative morbidity can also be devastating for survivors.

METHODS

We examined the short-term and long-term outcomes of 146 patients who underwent total aortic arch replacements between September 2003 and September 2011.

RESULTS

The overall in-hospital mortality was 4.8%, and major postoperative morbidity during hospitalization occurred in 29 patients (19.9%). Multivariate analyses demonstrated that risk factors for hospital death were left thoracotomy (odds ratio [OR], 51.92; p=0.01), high preoperative serum creatinine values (OR, 3.88; p=0.02), and intraoperative blood loss (OR, 1.01; p=0.04). Ruptured aorta (OR, 7.13; p=0.02) and previous myocardial infarction (OR, 5.13; p=0.04) were identified as independent risk factors for major postoperative morbidity. The postoperative survival of all patients at 5 years was 76.7%±5%. After hospital discharge, the standardized mortality ratios showed no significant difference between hospital survivors and a comparable Japanese population and were 1.09 (p=0.41) among patients without major morbidity and 1.82 (p=0.12) among those with major morbidity. The development of renal failure requiring hemodialysis increased the risk of long-term death (hazard ratio, 5.59; p=0.03), even among hospital survivors.

CONCLUSIONS

Our approach for total arch replacement resulted in low in-hospital mortality and morbidity. Long-term outcomes are stable in hospital survivors, especially in the absence of a postoperative requirement for dialysis.

Pseudoaneurysm of the ascending aorta 31 years after mitral valve replacement

We describe a rare case of an ascending aortic pseudoaneurysm 31 years after mitral valve replacement with a Björk-Shiley mechanical valve. The aneurysm presumably expanded gradually during the years following surgery. As the valve was functioning normally, it was left in situ while the ascending aorta was replaced. This report provides valuable information regarding the long-term nature of this patient's pseudoaneurysm, and the long-term durability of the Björk-Shiley spherical valve in the mitral position.

[Apico-aortic valved conduit for aortic stenosis in patients who could not tolerate median sternotomy]

This report presents 3 cases treated with an apico-aortic valved conduit. Cases 1, 2:A 67-year-old female patient and a 60-year-old male patient what had undergone coronary artery bypass grafting were admitted to our hospital for severe aortic stenosis. Computed tomography showed a severe calcified ascending aorta, and coronary angiography revealed patent bypass graft. Case 3:A 71-year-old male patient that had esophagectomy with retrosternal colonic interposition for esophagus cancer after distal gastrectomy. In addition, he had experienced anterior mediastinal drainagic therapy for anastomotic leak. All 3 patients were treated by implantation of an apico-aortic valved conduit. Operation:This procedure was performed through the 5th intercostal space under a beating heart with cardiopulmonary bypass.

RESULT

Postoperative courses were uneventful. All patients are still alive without procedure-related events.

CONCLUSION

This surgical procedure can be an effective alternative when conventional aortic valve replacement cannot be performed for aortic stenosis patients.

[Video-assisted thoracoscopic implantation of left ventricular pacing lead;usefulness of CARTO system;report of a case]

A 70-year-old man, with a history of broad anterior myocardial infarction and repeated several hospitalizations due to heart failure, was referred to our institution for cardiac resynchronization therapy. However, as intravenous implantation of the left ventricular pacemaker lead was not possible, the patient underwent video-assisted thoracoscopic (VAT) implantation. We noted broad myocardial scarring and patent grafts, along with previously bypassed left internal thoracic artery( LITA)-left anterior descending artery (LAD) and right internal thoracic artery (RITA)-D1;thus, the area suitable for implantation of the left ventricule (LV) pacemaker was believed to be restricted. Therefore, we decided to determine the viable myocardial area by using CARTO system and identify the appropriate access port positions for the subsequent VAT surgery. After the LV pacemaker lead was implanted, the recorded pacing threshold was found to be <1.2 V at 0.5 ms. Thus, the CARTO system might be useful to preoperatively identify an area suitable for surgical implantation of a LV pacemaker lead in patients with ischemic cardiomyopathy.

Predictors of late aortic events after Stanford type B acute aortic dissection

OBJECTIVE

Patients with Stanford type B acute aortic dissection usually receive medical treatment during the acute phase. The present study aimed to elucidate the factors predicting late aortic events in patients treated conservatively for acute type B dissections.

METHODS

From March 1991 to March 2011, 117 patients were enrolled in the present study, with a mean follow-up period of 5.1 ± 4.1 years. The patients were divided into 4 groups according to their false lumen status at onset: group F, fully open (n = 26, 22.2%); group P, partially thrombosed (n = 23, 19.6%); group U, ulcer-like projections (n = 22, 18.9%); and group T, completely thrombosed (n = 46, 39.3%).

RESULTS

Long-term survival did not significantly differ among the groups. The Kaplan-Meier event-free rate curve showed that aortic events occurred less frequently in group T than in the other 3 groups; the 5-year event-free rate was 65.4%, 58.8%, 36.1%, and 95.7% for groups F, P, U, and T, respectively. Cox regression analysis showed that the presence of ulcer-like projections (P = .016) and a maximum aortic diameter of ≥ 40 mm (P = .003) were predictors of late aortic events.

CONCLUSIONS

When patients have a maximum aortic diameter of ≥40 mm or ulcer-like projections at onset, early surgical intervention should be considered to prevent positive remodeling of the aorta.

Transapical extirpation of a left ventricular thrombus in Takotsubo cardiomyopathy

A 58-year-old Japanese female was referred to our hospital. Although the electrocardiogram showed ST elevation, coronary angiography showed intact coronary artery. We diagnosed Takotsubo cardiomyopathy and a left ventricular thrombus. Anticoagulation was administered; however, the left ventricular thrombus had become mobile and protrusive. We extirpated the left ventricular thrombus via trans-apical approach. Left ventricular thrombus is rare in Takotsubo cardiomyopathy, but these patients are at a higher risk of thromboembolism, especially if the thrombi are mobile and protruding.

Ratio of preoperative atrial natriuretic peptide to brain natriuretic peptide predicts the outcome of the maze procedure in mitral valve disease

Background

Although the maze procedure is an established surgical treatment for eliminating atrial fibrillation (AF), its efficacy in patients with mitral valve disease has remained unsatisfactory. A useful predictive marker for the outcome of the maze procedure is needed. The aim of this study was to investigate whether the preoperative ratio of atrial natriuretic peptide (ANP) to brain natriuretic peptide (BNP) reflects atrial fibrosis and can be used to predict the maze procedure outcome in patients with mitral valve disease.

Methods

A total of 23 consecutive patients who underwent the radial approach to the maze procedure combined with mitral valve surgery were included in this study and were divided into a sinus rhythm (SR) group (n=16) and an AF group (n=7) based on postoperative cardiac rhythm. Plasma samples were obtained at rest before the operation and were analysed for ANP and BNP levels. Atrial tissue samples taken during surgery were used to quantify interstitial fibrosis.

Results

The preoperative ANP-to-BNP ratio in the SR group was significantly higher than that in the AF group (0.74 +/− 0.29 vs. 0.42 +/− 0.28, respectively; p=0.025). Receiver operating characteristic (ROC) curve analysis was used to identify factors that predict outcomes after the maze procedure. The area under the ROC curve for the ANP-to-BNP ratio (0.81) was greater than for any other preoperative factors. Moreover, the preoperative ANP-to-BNP ratio demonstrated a negative correlation with left atrial fibrosis (r=−0.69; p=0.003).

Conclusions

The preoperative ANP-to-BNP ratio can predict maze procedure outcome in patients with mitral valve disease, and it represents a potential biomarker for left atrial fibrosis.

Arch translocation and the intra-arch elephant-trunk technique with collared graft for extended chronic dissecting aortic aneurysm

Management of extensive, chronic, dissecting aortic aneurysms after prior repair of the ascending aorta presents a technical challenge for surgeons. A symptomatic 64-year-old patient was admitted for elective surgical repair of an aortic annular dilatation, causing severe aortic regurgitation, and a Crawford type II extended thoracoabdominal aneurysm, 4 years after he underwent primary repair of an acute aortic dissection. The aorta was diffusely dilated, and there were no sites beyond the distal aortic arch where anastomosis could be performed. We successfully performed total aortic replacement with a 2-stage strategy, using an arch translocation technique and an intra-arch elephant-trunk technique.

Important role of the angiotensin II pathway in producing matrix metalloproteinase-9 in human thoracic aortic aneurysms

BACKGROUND

The precise pathologic mechanisms underlying human thoracic aortic aneurysms (TAAs) remain uncertain, except that matrix metalloproteinase-9 (MMP-9) is considered a key enzyme for the degradation of extracellular matrix in aneurysm walls. The aim of this study was to elucidate the significance of the angiotensin II (AngII) pathway to MMP-9 production in human TAA walls.

METHODS AND RESULTS

We examined the activation of Smad2, a common downstream molecule of AngII and transforming growth factor β (TGF-β) pathways, and the expression of MMP-9 in human nonsyndromic TAA walls. We observed significant increases in Smad2 activation and MMP-9 expression, associated with disruption of elastic lamellae. Using human TAA walls in ex vivo culture, we investigated whether AngII and/or TGF-β pathways are essential for MMP-9 production. Unexpectedly, TGF-β receptor inhibitor had no effect on MMP-9 production. We used PD98059, an inhibitor of extracellular signal-regulated kinase (ERK) activation, and demonstrated that PD98059 dramatically reduced MMP-9 production with attenuation of Smad2 activation. Moreover, exogenous AngII resulted in increases in Smad2 activation and MMP-9 production, in an ERK-dependent manner.

CONCLUSION

Our findings indicate that the AngII/ERK pathway has an important role in the production of MMP-9 in human nonsyndromic TAA walls.

Heat shock factor 1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of bone marrow stem/progenitor cells

Bone marrow (BM)-derived stem/progenitor cells play an important role in ischemia-induced angiogenesis in cardiovascular diseases. Heat shock factor 1 (HSF1) is known to be induced in response to hypoxia and ischemia. We examined whether HSF1 contributes to ischemia-induced angiogenesis through the mobilization and recruitment of BM-derived stem/progenitor cells using HSF1-knockout (KO) mice. After the induction of ischemia, blood flow and microvessel density in the ischemic hindlimb were significantly lower in the HSF1-KO mice than in the wild-type (WT) mice. The mobilization of BM-derived Sca-1- and c-kit-positive cells in peripheral blood after ischemia was significantly lower in the HSF1-KO mice than in the WT mice. BM stem/progenitor cells from HSF1-KO mice showed a significant decrease in their recruitment to ischemic tissue and in migration, adhesion, and survival when compared with WT mice. Blood flow recovery in the ischemic hindlimb significantly decreased in WT mice receiving BM reconstitution with donor cells from HSF1-KO mice. Conversely, blood flow recovery in the ischemic hindlimb significantly increased in HSF1-KO mice receiving BM reconstitution with donor cells from WT mice. These findings suggest that HSF1 contributes to ischemia-induced angiogenesis by regulating the mobilization and recruitment of BM-derived stem/progenitor cells.

[Surgical therapy for ischemic cardiomyopathy]

BACKGROUND

Surgical ventricular restoration (SVR) is considered as an effective surgical procedure for patients with ischemic myocardiopathy( ICM). However" surgical treatment for ischemic heart failure (STICH)" trial concluded that adding SVR to coronary artery bypass grafting (CABG) did not relieve symptoms and failed to lower death rate or cardiac rehospitalization as compared with CABG alone.

AIM

The aim of this study was to investigate the efficacy of CABG with SVR for ICM.

METHODS AND RESULTS

We retrospectively studied 24 patients who had undergone CABG with or with out SVR for ICM from October 1992 to June 2008. In CABG with SVR group, cardiac symptoms were relieved and the left ventricular end-systolic volume index (LVESVI) was reduced from the baseline significantly. However cardiac symptoms were relieved only in CABG-S [left ventricular end-diastolic dimension (LVDd)<60 mm] group, and not in CABG-L (LVDd≥60 mm) group. LVESVI was not reduced in CABG without SVR group.

CONCLUSION

SVR contributed to relieving the symptoms, and improving the left ventricular function and the long-term survival of patients with especially dilated ICM, which could not be achieved by CABG alone.

The effects of mechanical stress on the growth, differentiation, and paracrine factor production of cardiac stem cells

Stem cell therapies have been clinically employed to repair the injured heart, and cardiac stem cells are thought to be one of the most potent stem cell candidates. The beating heart is characterized by dynamic mechanical stresses, which may have a significant impact on stem cell therapy. The purpose of this study is to investigate how mechanical stress affects the growth and differentiation of cardiac stem cells and their release of paracrine factors. In this study, human cardiac stem cells were seeded in a silicon chamber and mechanical stress was then induced by cyclic stretch stimulation (60 cycles/min with 120% elongation). Cells grown in non-stretched silicon chambers were used as controls. Our result revealed that mechanical stretching significantly reduced the total number of surviving cells, decreased Ki-67-positive cells, and increased TUNEL-positive cells in the stretched group 24 hrs after stretching, as compared to the control group. Interestingly, mechanical stretching significantly increased the release of the inflammatory cytokines IL-6 and IL-1β as well as the angiogenic growth factors VEGF and bFGF from the cells in 12 hrs. Furthermore, mechanical stretching significantly reduced the percentage of c-kit-positive stem cells, but increased the expressions of cardiac troponin-I and smooth muscle actin in cells 3 days after stretching. Using a traditional stretching model, we demonstrated that mechanical stress suppressed the growth and proliferation of cardiac stem cells, enhanced their release of inflammatory cytokines and angiogenic factors, and improved their myogenic differentiation. The development of this in vitro approach may help elucidate the complex mechanisms of stem cell therapy for heart failure.

Validation of the JapanSCORE versus the logistic EuroSCORE for predicting operative mortality of cardiovascular surgery in Yamaguchi University Hospital

PURPOSE

Recent studies have shown that the European System for Cardiac Operative Risk Evaluation (Euro-SCORE) is a reliable risk model in cardiac surgery. In Japan, the JapanSCORE has been devised as the Japanese original risk model for cardiovascular surgery. We evaluated the validity of the JapanSCORE, especially in comparison with the logistic EuroSCORE METHODS: We calculated the predicted mortality according to two risk models for 523 consecutive patients who underwent cardiovascular surgery within a 6-year period (July 2003 to June 2009) at Yamaguchi University Hospital. We assessed the scores' validity by calculating the area under the receiver operating characteristics curve (C-index) and by the chi-squared test or Fisher's exact test.

RESULTS

The C-indexes were 0.688 with the logistic EuroSCORE and 0.770 with the JapanSCORE (P = 0.053). Although the difference was not significant, the JapanSCORE tended to be more accurate. The C-indexes limited to isolated coronary artery bypass grafting (CABG) were 0.564 with the logistic EuroSCORE and 0.790 with the JapanSCORE (P = 0.001). The Japan-SCORE was significantly more valid than the logistic EuroSCORE for isolated CABG. The actual mortality was 4.0%; the mean predictive mortality was 5.6% with the JapanSCORE and 15.1% with the logistic Euro-SCORE. The mortality predicted by the JapanSCORE was closer to the observed mortality. There was a significant difference between the observed mortality and the logistic EuroSCORE (P < 0.0001).

CONCLUSION

The JapanSCORE seems to be a more reliable risk model than the logistic EuroSCORE for patients undergoing cardiac or thoracic aortic surgery at Yamaguchi University Hospital.