Toshihito Gomibuchi

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.

Mycotic Iliac Artery Aneurysm Caused by Clostridiumdifficile in a Patient with Axillobifemoral Bypass for Leriche Syndrome

A 74-year old man on hemodialysis developed a mycotic aneurysm caused by Clostridium difficile. To the best of our knowledge, this is only the second case of such an aneurysm reported in the literature. He had previously undergone axillobifemoral bypass grafting because of symptomatic infrarenal aortic stenosis. Although no blood flow was detected in his occluded right common iliac artery, it expanded rapidly despite intensive antibiotic therapy. As the blood supply to the lower limbs was already secured, only resection of the infected arteries was performed.

Hybrid thoracic endovascular aortic repair of ascending aortic pseudoaneurysm

We report the successful thoracic endovascular aortic repair of an ascending aortic pseudoaneurysm. Because the risk of resternotomy after conventional surgery was very high, endovascular repair with extra-anatomic reconstruction of the supra-aortic vessels was performed using the femoral artery as the donor artery. Complete exclusion of the pseudoaneurysm was achieved, with no postoperative complications or neurologic sequelae.

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.

Early results of aortic root reoperation

Background Reoperation of aortic root is considered challenging because of technical difficulty and relatively low incidence of surgical indications. It is still not clear whether the redo root surgery could be performed safely although the primary Bentall procedure is a safe and established operation for aortic root surgery. We evaluated early outcomes of reaortic root replacement comparing to primary Bentall operation.