Tatsuichiro Seto

Allogeneic transplantation of iPS cell-derived cardiomyocytes regenerates primate hearts

Induced pluripotent stem cells (iPSCs) constitute a potential source of autologous patient-specific cardiomyocytes for cardiac repair, providing a major benefit over other sources of cells in terms of immune rejection. However, autologous transplantation has substantial challenges related to manufacturing and regulation. Although major histocompatibility complex (MHC)-matched allogeneic transplantation is a promising alternative strategy, few immunological studies have been carried out with iPSCs. Here we describe an allogeneic transplantation model established using the cynomolgus monkey (Macaca fascicularis), the MHC structure of which is identical to that of humans. Fibroblast-derived iPSCs were generated from a MHC haplotype (HT4) homozygous animal and subsequently differentiated into cardiomyocytes (iPSC-CMs). Five HT4 heterozygous monkeys were subjected to myocardial infarction followed by direct intra-myocardial injection of iPSC-CMs. The grafted cardiomyocytes survived for 12 weeks with no evidence of immune rejection in monkeys treated with clinically relevant doses of methylprednisolone and tacrolimus, and showed electrical coupling with host cardiomyocytes as assessed by use of the fluorescent calcium indicator G-CaMP7.09. Additionally, transplantation of the iPSC-CMs improved cardiac contractile function at 4 and 12 weeks after transplantation; however, the incidence of ventricular tachycardia was transiently, but significantly, increased when compared to vehicle-treated controls. Collectively, our data demonstrate that allogeneic iPSC-CM transplantation is sufficient to regenerate the infarcted non-human primate heart; however, further research to control post-transplant arrhythmias is necessary.

Therapeutic angiogenesis by bone marrow implantation for critical hand ischemia in patients with peripheral arterial disease : a pilot study

ABSTRACT Objective: Implantation of bone marrow mononuclear cells (BM-MNCs), including endothelial progenitor cells, into ischemic lower limbs has been shown to improve symptoms in patients with peripheral arterial diseases (PAD). This study investigated whether BM-MNC implantation (BMI) is also effective for the ischemic hands of these patients. Methods: Seven PAD patients with hand ischemia were enrolled: six patients had thromboangiitis obliterans and one had collagen disease. All seven had symptoms involving either resting pain or non-healing ischemic ulcers of the hand. Approximately 600 mL of MNCs were separated from BM and concentrated to a final volume of 40–50 mL, which were injected into ischemic hands. Ischemic status was evaluated by measuring the digital/brachial pressure index (DBI), visual analog pain scale, and the healing of ulcers before and 6 months after BMI. Results: The mean number of implanted MNCs, CD34-positive cells, and CD34,133-positive cells was 3.67 ± 0.53 × 109, 4.94 ± 2.45 × 107, and 2.52 ± 1.57 × 107, respectively. Mean DBI in those patients was 0.15 ± 0.30 before BMI and significantly increased to 0.67 ± 0.19 at 6 months after BMI ( p = 0.004). All patients also showed improvement of pain scale and ischemic ulcers. There was no significant correlation between the number of implanted cells and improvement in the degree of DBI or the pain scale. Conclusion: Autologous BMI could be a promising and safe method of therapeutic angiogenesis for critical hand ischemia in PAD patients.

Upregulation of the apoptosis-related inflammasome in cardiac allograft rejection

BACKGROUND Inflammation is a major factor in cardiac allograft rejection. Accumulating reports have demonstrated an important role of the inflammation-induced adaptor complex, called the inflammasome, in the field of immunology. The apoptosis-associated, speck-like protein containing a caspase recruitment domain (ASC) is an adaptor protein that forms the inflammasome and regulates caspase-1-dependent generation of inflammatory cytokines. The aim of the present study was to determine how ASC is associated with the development of cardiac allograft rejection. METHODS We used a murine heterotopic cardiac transplantation model between fully incompatible strains. Donor hearts (n = 9 for each time-point) were harvested for examination on Days 1, 4, 7 and 12 after transplantation. Histopathologic findings of cardiac grafts were evaluated using rejection scores. The expression of ASC and inflammatory cytokines in cardiac grafts were analyzed by immunohistochemistry and real-time reverse transcript-polymerase chain reaction (RT-PCR). RESULTS Expression levels of both ASC and IL-1 beta were higher in the myocardial interstitium of allografts in parallel to the progress of cardiac rejection during the acute phase after transplantation. In contrast, expression of ASC and IL-1 beta remained low in isografts. Cardiac allografts treated with tacrolimus showed decreased expression of both ASC and IL-1 beta similar to that seen in isografts. Real-time RT-PCR demonstrated similar alteration of ASC and IL-1 beta mRNA expression in cardiac grafts during the acute phase. CONCLUSIONS Our results demonstrate a novel finding showing that upregulation of ASC is closely associated with the inflammation induced in cardiac grafts after transplantation in the mouse.

Surgical Outcomes of Acute Type A Aortic Dissection in Elderly Patients

BACKGROUND Age is still considered a risk factor in the repair of acute type A aortic dissection. Instead of total arch replacement, we performed hemiarch or partial arch replacement with intimal tear exclusion to reduce death in elderly patients and evaluated early-term and midterm outcomes. METHODS From January 2004 to April 2012, 59 patients older than 70 years (mean age, 77.0±4.3 years) underwent emergency operations for acute type A aortic dissection at our institution. We performed hemiarch, partial arch, or total arch replacement, according to the location of the primary entry tear. The characteristics, surgical procedures, and early-term and midterm outcomes of these patients were reviewed. RESULTS We performed hemiarch replacement in 47 patients, partial arch replacement in 4, and total arch replacement in 8. The primary entry site was excluded in 56 of 59 patients (94.9%). In-hospital mortality was 6.8%, and neurologic impairment occurred in 25.4%. We obtained midterm outcomes for 55 of 59 patients, with a mean follow-up period of 43.9±23.7 months. Fourteen patients died, two of these of aortic-related causes. One patient required repeat aortic operation for rupture of a pseudoaneurysm. Follow-up computed tomography imaging was done in 28 of 55 patients during the 12 months after the operation. No significant difference was noted in the increase in maximal aortic diameter between patients with and without residual dissection. CONCLUSIONS In-hospital mortality was 6.8%; relatively low compared with previous reports. Hemiarch and partial arch replacement with entry tear exclusion may reduce deaths associated with acute type A aortic dissection repair in elderly patients, without increasing the risk of reoperation and aortic-related death.

Tracheo-Bronchial Obstruction and Esophageal Perforation after TEVAR for Thoracic Aortic Rupture.

A 67-year-old man was referred to our hospital for an ascending aortic aneurysm, thoracoabdominal aortic aneurysm and aortic regurgitation. Graft repair of the thoracic aortic arch and aortic valve replacement was given priority and completed, however he developed descending aortic rupture before the second scheduled surgery, and endovascular stent grafting was performed. He subsequently developed tracheobronchial obstruction and esophageal perforation. The patient underwent urgent esophagectomy and enterostomy with continuity later reestablished. However, he died of sepsis 5 months after surgery. Despite the less invasive nature of endovascular treatment, esophageal perforation can nevertheless occur and postoperative vigilance is well warranted.

Innovative Application of Available Stent Grafts in Japan in Aortic Aneurysm Treatment—Significance of Innovative Debranching and Chimney Method and Coil Embolization Procedure

OBJECTIVE We here describe our experience with innovative uses of these devices. PATIENTS AND METHODS We reviewed treatment outcomes of 310 endovascular abdominal aortic repair (EVAR) and 83 thoracic endovascular aortic repair (TEVAR) cases performed between August 2007 and February 2012. We separately assessed results in elderly and high-risk patients who had a novel procedure. This group included 94 patients who underwent EVAR with IIA embolization, 10 patients who had EVAR and a renal artery chimney procedure for a short aortic neck, 20 patients who had two de-branching TEVAR or Chimney method for thoracic aortic aneurysms (TAA) and 3 patients who had debranching TEVAR for thoracic abdominal aortic aneurysms (TAAA). RESULTS Of the 393 patients given stent grafts (SGs), 3 (0.8%) died in the hospital, including 1 patient with pneumonia who underwent EVAR and IIA embolization and 1 patient with a cerebral infarction who had TEVAR. Four patients (4.3%) who were treated with EVAR with internal iliac artery (IIA) embolization presented with residual buttock claudication 6 months postoperatively, and 3 patients (3.2%) had onset of ischemic enteritis; however, in all 7 patients, the condition resolved without additional intervention. In the 10 patients who had EVAR and a renal artery chimney method, the landing zone (LZ) was ≤10 mm, but neither endoleak nor renal artery occlusion was observed perioperatively or during midterm follow-up. Of the 20 patients who had a 2-debranching TEVAR, including 9 in whom the chimney method was used with the LZ in zone 0, 1 (5%) had a residual endoleak. In 3 patients with TAAA, we used SGs to cover 4 abdominal branches and bypassed the visceral artery; the outcomes were good, with all patients being ambulatory at hospital discharge. CONCLUSION Among innovative SGs treatments, the debranching procedure and the chimney method using catheterization and the coil-embolization technique provided good outcomes, as used in addition to surgical procedures. Aortic aneurysm treatment will become increasingly noninvasive with the continuing development of more innovative ways to use the SGs currently available in Japan. (English Translation of Jpn J Vasc Surg 2012; 21: 165-173).

Structural Valve Deterioration of Porcine Bioprosthesis Soon after Mitral Valve Repair and Replacement

An 81-year-old woman, who had undergone mitral valve replacement (MVR) with a porcine bioprosthesis after mitral valve repair, presented with hemolysis 4 years and 6 months after MVR. Transthoracic echocardiography (TTE) revealed trivial mitral regurgitation, which was diagnosed based on the observed perivalvular leakage. Hemolysis gradually increased, and she developed dyspnea and edema 2 years after the appearance of mitral regurgitation. We performed a reoperation. Intraoperative transesophageal echocardiography (TEE) after intubation showed no perivalvular leakage of the mitral prosthesis, but transvalvular leakage through a leaflet perforation was present. The leaflets of the bioprosthesis had slit-shaped perforations at their hinges. There was no sign of infection on the leaflet or annulus. We implanted a new bioprosthesis after removal of the deteriorated valve. The postoperative course was uneventful. Microscopic examination verified collagen degeneration, histiocyte infiltration, and hyalinization. It is important to perform TEE to rule out structural valve deterioration (SVD) even when regurgitation occurs soon after valve replacement.

Surgical Repair of Cervical Aortic Arch With Brain Circulation Anomaly Through Clamshell Incision

We report the successful surgical repair of a cervical aortic arch and diverticulum with a brain circulation anomaly through a clamshell incision. Because of the reliability of selective antegrade cerebral perfusion and superior exposure, we chose an approach through a clamshell incision. We describe the utility of this approach for treating a cervical aortic arch with a diverticulum.

Delayed Esophageal Perforation Secondary to Thoracic Aortic Aneurysm Rupture in a Patient with Human Immunodeficiency Virus Infection

A 65-year-old man infected with human immunodeficiency virus underwent emergency surgery for rupture of a mycotic descending thoracic aneurysm. The aneurysm was replaced with a prosthetic graft wrapped with omentum. Esophageal perforation occurred 3 weeks after surgery. The patients condition remained stable, and we adopted a conservative treatment. The esophageal fistula had not healed completely and a biopsy of the scar revealed gastric cancer. We performed a distal gastrectomy, Roux-Y reconstruction, and enterostomy for enteral feeding. Follow-up endoscopy revealed healing of the fistula, and the patient was eventually discharged. We managed this potentially fatal complication with minimally invasive treatment.

Increased Expression of Y-Box-Binding Protein-1 in Hind-Limb Muscles During Regeneration from Ischemic Injury in Mice

Critical limb ischemia (CLI) is the most severe complication of peripheral arterial disease (PAD). Understanding the molecular mechanisms underlying tissue repair after CLI is necessary for preventing PAD progression. Y-box binding protein-1 (YB-1) regulates the expression of many genes in response to environmental stresses. We aimed to determine whether YB-1 is involved in ischemic muscle regeneration. A mouse ischemic hind-limb model was generated; namely, the femoral, saphenous, and popliteal arteries in the left hind limb were ligated. The right hind limb, with skin incisions alone, served as control. Hind limbs (n = 3-5 for each time point) were examined on day 0 (before the operation) and on postoperative days 1, 2, 7, 10, and 14, and the biceps femoris, adductor, rectus femoris, and gracilis muscles were subjected to histopathological and immunohistochemical analyses. In ischemic limbs, myogenesis, triggered by an increase in myotubes, began on day 7; thereafter, regenerated muscles gradually increased in volume. RT-PCR analysis showed that YB-1 mRNA levels were increased in the limbs after ischemic injury, peaked on day 2, and subsequently decreased. On day 7, expression levels of MyoD and alpha-smooth muscle actin (αSMA) mRNAs were significantly higher in ischemic muscles than in control muscles. Immunohistochemical analysis revealed increased YB-1 immunoreactivity in myoblasts and myotubes on day 7, which was decreased by day 14. The immunoreactive αSMA and smooth muscle myosin heavy chain were transiently increased in myotubes. This is the first report showing the increased expression of YB-1 during muscle regeneration after ischemic injury.