Taichi Sakaguchi

Tissue engineered myoblast sheets improved cardiac function sufficiently to discontinue LVAS in a patient with DCM: report of a case

Dilated cardiomyopathy (DCM) is a heart muscle disease characterized by progressive heart failure, and is a leading cause of mortality and morbidity. Recently, cellular therapy for end-stage heart failure has been emerging. We herein report a 56-year-old male who received a transplant of autologous myoblast sheets manufactured in temperature-responsive culture dishes. His clinical condition improved markedly, leaving him without any arrhythmia and able to discontinue using a left ventricular assist system and avoid cardiac transplantation. These findings suggest that cellular therapy using myoblast sheets is a promising new strategy for treating patients with end-stage DCM. This method might be an effective alternative to heart transplantation in the near future.

Impaired myocardium regeneration with skeletal cell sheets--a preclinical trial for tissue-engineered regeneration therapy.

Background. We hypothesized that autologous skeletal cell (SC) sheets regenerate the infract myocardium in porcine heart as a preclinical trial. Methods and Results. The impaired heart was created by implantation of ameroid constrictor on left anterior descending for 4 weeks. SCs isolated from leg muscle were cultured and detached from the temperature-responsive domain-coated dishes as single monolayer cell sheet at 20°C. The following therapies were conducted: SC sheets (SC group, n=5); sham (C group n=5). Echocardiography demonstrated that cardiac performance was significantly improved in the SC group 3 and 6 months after operation (fractional area shortening, 3 months; SC vs. C=49.5±2.8 vs. 24.6±2.0%, P<0.05) and left ventricle dilatation was well attenuated in the SC group. Color kinesis index showed that distressed regional diastolic and systolic function in infarcted anterior wall was significantly recovered (SC vs. C=57.4±8.6 vs. 30.2±4.7%, P<0.05, diastolic: 58.5±4.5 vs. 35.4±6.6%, P<0.05, systolic). Factor VIII immunostains demonstrated that vascular density was significantly higher in the SC group than the C group. And % fibrosis and cell diameter were significantly lower in the SC group. And hematoxylin-eosin staining depicted that skeletal origin cells and well-developed-layered smooth muscle cells were detected in the implanted area. Positron emission tomography showed better myocardial perfusion and more viable myocardial tissue in the distressed myocardium receiving SC sheets compared with the myocardium receiving no sheets. Conclusions. SC sheet implantation improved cardiac function by attenuating the cardiac remodeling in the porcine ischemic myocardium, suggesting a promising strategy for myocardial regeneration therapy in the impaired myocardium.

In situ tissue regeneration using a novel tissue-engineered, small-caliber vascular graft without cell seeding

OBJECTIVE Various types of natural and synthetic scaffolds with arterial tissue cells or differentiated stem cells have recently attracted interest as potential small-caliber vascular grafts. It was thought that the synthetic graft with the potential to promote autologous tissue regeneration without any seeding would be more practical than a seeded graft. In this study, we investigated in situ tissue regeneration in small-diameter arteries using a novel tissue-engineered biodegradable vascular graft that did not require ex vivo cell seeding. METHODS Small-caliber vascular grafts (4 mm in diameter) were fabricated by compounding a collagen microsponge with a biodegradable woven polymer tube that was constructed in a plain weave pattern with a double layer of polyglycolic acid (core) and poly-L-lactic acid (sheath) fibers. We implanted these tissue-engineered vascular grafts bilaterally into the carotid arteries of mongrel dogs (body weight, 20-25 kg). No anticoagulation regimen was used after implantation. We sacrificed the dogs 2, 4, 6, and 12 months (n = 4 in each group) after implantation and evaluated the explants histologically and biochemically. RESULTS All of the tissue-engineered vascular grafts were patent with no signs of thrombosis or aneurysm at any time. Histologic and biochemical examinations showed excellent in situ tissue regeneration with an endothelial cell monolayer, smooth muscle cells, and a reconstructed vessel wall with elastin and collagen fibers. CONCLUSION Our study indicated that this novel tissue-engineered vascular graft promoted in situ tissue regeneration and did not require ex vivo cell seeding, thereby conferring better patency on small-caliber vascular prostheses.

NF-κB decoy suppresses cytokine expression and thermal hyperalgesia in a rat neuropathic pain model

Pro-inflammatory cytokines have been shown to be involved in the genesis, persistence, and severity of neuropathic pain following nerve injury. The transcription factor, nuclear factor-kappa B (NF-κB), plays a pivotal role in regulating pro-inflammatory cytokine gene expression. To elucidate the role of NF-κB in the pathogenesis of neuropathic pain, using a gene-based approach of NF-κB decoy, we tested whether the activated NF-κB affected pain behavior via the expression of inflammatory mediators. Single endoneurial injections of NF-κB decoy, at the site of nerve lesion, significantly alleviated thermal hyperalgesia for up to 2 weeks and suppressed the expression of mRNA of the inflammatory cytokines, iNOS, and adhesion molecules at the site of nerve injury. This finding suggests that a perineural inflammatory cascade, that involves NF-κB, is involved in the pathogenesis of neuropathic pain.

Extinguishing Egr-1-dependent inflammatory and thrombotic cascades after lung transplantation

Hypoxic induction of the early growth response‐1 (Egr‐1) transcription factor initiates proinflammatory and procoagulant gene expression. Orthotopic/isogeneic rat lung transplantation triggers Egr‐1 expression and nuclear DNA binding activity corresponding to Egr‐1, which leads to increased expression of downstream target genes such as interleukin‐1β, tissue factor, and plasminogen activator inhibitor‐1. The devastating functional consequences of Egr‐1 up‐regulation in this setting are prevented by treating donor lungs with a phosphorothioate antisense oligodeoxyribonucleotide directed against the Egr‐1 translation initiation site, which blocks expression of Egr‐1 and its gene targets. Post‐transplant graft leukostasis, inflammation, and thrombosis are consequently diminished, with marked improvement in graft function and recipient survival. Blocking expression of a proximal transcription factor, which activates deleterious inflammatory and coagulant effector mechanisms, is an effective molecular strategy to improve organ preservation.

Cerebral microbleeds predict impending intracranial hemorrhage in infective endocarditis.

Background: Cerebral microbleeds (CMBs) detected by T2*-weighted MRI are a potential indicator of hypertension, microvascular disease and hemorrhagic stroke. An association between infective endocarditis (IE) and CMBs has been reported recently, but the clinical significance remains unclear. We hypothesized that CMBs in patients with IE are associated with vascular vulnerabilities such as mycotic aneurysm or pyogenic vasculitis. Methods: We retrospectively reviewed 26 consecutive patients with definite IE who underwent T2*-weighted MRI and were admitted to 2 medical centers in Osaka, Japan, between January 2006 and June 2010. We examined the incidence of symptomatic intracranial hemorrhage (ICH) occurring after initial MRI examination and investigated the association between ICH, CMBs and other clinical characteristics. Results: CMBs were identified in 14 patients (54%), and 72% of CMBs were found in the lobar region. Symptomatic ICH was observed in 8 patients (31%) during the 3-month follow-up period after initial MRI examination. In multiple logistic regression analyses, the presence of preceding ICH [odds ratio (OR) 40.0, 95% confidence interval (CI) 2.5–2,870] and the presence of CMBs (OR 34.0, 95% CI 1.3–17,300) were independent predictors of the development of ICH. Using cutoff values for CMBs of ≧2 and ≧3, the adjusted ORs for ICH increased (OR 42.1, 95% CI 1.9–24,300, and OR 70.1, 95% CI 2.5–105,000, respectively). Conclusions: In addition to prior ICH, the presence of CMBs was a strong predictor of impending ICH in patients with IE. CMBs might represent vascular vulnerability related to IE.

Bioengineered Myocardium Derived from Induced Pluripotent Stem Cells Improves Cardiac Function and Attenuates Cardiac Remodeling Following Chronic Myocardial Infarction in Rats

Cell‐based therapies are promising strategies for myocardial repair following myocardial infarction. Induced pluripotent stem (iPS) cells have the potential to generate many cardiomyocytes, and they hold significant promise for the application of regenerative medicine to heart failure. Here, we developed cardiac tissue sheets, termed bioengineered myocardium (BM), from mouse iPS cells and measured cardiac performance following BM implantation in a rat chronic myocardial infarction model. Immunostaining analyses revealed that the α‐actinin+ cell population was isolated with more than 99% purity under specific culture conditions. To evaluate the contribution of BM to the improvements in cardiac performance, we induced myocardial infarction in 30 F344/NJcl‐rnu/rnu rats by left anterior descending coronary ligation. The rats were randomly divided into two groups, 2 weeks after ligation: a BM implantation group (n = 15) and a sham group (n = 15). Echocardiography and catheter examination showed that the BM implantation significantly improved cardiac function and attenuated cardiac remodeling compared with the sham group. Histological analyses demonstrated that the implanted BM survived at the epicardial implantation site 4 weeks after implantation. The implanted BM survived and attenuated left ventricular remodeling in the rat chronic myocardial infarction model. Thus, BM derived from iPS cells might be a promising new treatment for heart failure.

Biventricular support using implantable continuous-flow ventricular assist devices

A 34-year-old woman with fulminant myocarditis underwent emergent implant with the Toyobo (Nipro, Osaka, Japan) paracorporeal biventricular assist device (BiVAD). The patient had been stable for 6 months, until she started to develop heart failure symptoms due to severe pulmonary insufficiency. Pulmonary valve closure and BiVAD conversion to implantable rotary pumps was performed. A DuraHeart centrifugal pump (Terumo Heart Inc., Ann Arbor, MI) was used for left ventricular assist, and a Jarvik 2000 axial-flow pump (Jarvik Heart Inc., New York, NY) was used for right ventricular assist. Although strict management was required to balance the flow rates of the two different types of devices, her postoperative course was uneventful and she was discharged home.

Cardiac fibrosis and cellular hypertrophy decrease the degree of reverse remodeling and improvement in cardiac function during left ventricular assist

BACKGROUND This study investigated if the degree of cardiac fibrosis and myocyte size at the time of left ventricular assist device (LVAD) implantation predicts the degree of improvement in cardiac function and sustained recovery after LVAD explantation. METHODS The study included 34 patients who underwent LVAD-off test. LV end-diastolic (LVEDD) and end-systolic diameter (LVESD), LV ejection fraction (LVEF), mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure (PCWP), and cardiac index (CI) were measured before LVAD implantation and during LVAD-off test. Myocardial tissue was obtained from the apical core at LVAD implantation. RESULTS The degree of cardiac fibrosis had significant correlations with changes in LVEDD (r = -0.725, p < 0.0001), LVESD (r = -0.800, p < 0.0001), LVEF (r = -0.637, p < 0.0001), mPAP (r = -0.569, p = 0.0010), PCWP (r = -0.463, p = 0.0123), and CI (r = -0.544, p = 0.0015). Myocyte size also had significant correlations with changes in LVEDD (r = -0.386, p = 0.0235), LVESD (r = -0.414, p = 0.0141), and LVEF (r = -0.528, p = 0.0015). The LVAD was successfully removed in 9 patients. The degree of cardiac fibrosis and myocyte size in these patients was significantly smaller compared with the patients who did not undergo LVAD removal. CONCLUSIONS Cardiac fibrosis and myocyte size at the time of LVAD implantation were significant predictors of degree of improvement of cardiac function and the sustained recovery after the LVAD explantation.

Impact of Early Surgical Treatment on Postoperative Neurologic Outcome for Active Infective Endocarditis Complicated by Cerebral Infarction

BACKGROUND The optimal timing of surgical intervention for infective endocarditis (IE) with cerebrovascular complications remains controversial because the risk of perioperative intracranial hemorrhage is still unclear. The aim of this study was to investigate the prevalence of acute cerebral infarction (CI) in patients with IE and its hemorrhagic risk after valve operations. METHODS We retrospectively evaluated 102 consecutive patients (35 with neurologic symptoms; 67 without neurologic symptoms) who underwent diffusion-weighted magnetic resonance imaging (DW-MRI) before valve operations for left-sided active IE between 2005 and 2010. The prevalence of acute CI and its postoperative neurologic outcome were evaluated. RESULTS Acute CI was detected preoperatively in 64 of 102 (62.7%) patients. Of the 64 patients with acute CI, 34 underwent surgical treatment within 14 days after diagnosis of CI (early group), whereas the other 30 patients underwent operation after more than 14 days (delayed group). Postoperative CI deterioration was confirmed in 1 patient in each group. Furthermore, in 43 of the patients with acute CI who were followed with postoperative neuroimaging, hemorrhagic transformation was confirmed in only 1 patient in the delayed group. However new ectopic intracranial hemorrhage was confirmed in 2 patients in the early group and 3 patients in the delayed group. CONCLUSIONS The risk of postoperative hemorrhagic transformation of preoperative acute CI was low, even in patients who underwent early operation. Our data suggested that there is no benefit for delaying surgical treatment beyond 2 weeks to prevent hemorrhagic transformation in patients with CI. However ectopic intracranial hemorrhage sometimes occurs regardless of the timing of surgical treatment.