Mitsuteru Handa

Thymidine Phosphorylase Gene Transfer Inhibits Vascular Smooth Muscle Cell Proliferation by Upregulating Heme Oxygenase-1 and p27KIP1

Objective—Thymidine phosphorylase (TP) reportedly promotes endothelial cell migration and induces heme oxygenase (HO)-1 expression. However, its effect on vascular smooth muscle cells (VSMCs) is poorly understood. In this study, we examined the effect of TP on VSMCs in vitro and in vivo. Methods and Results—Phagemid vector encoding human TP gene was transfected into rat VSMCs, and a clone overexpressing TP was selected (C2). C2 showed a slower migration and proliferation than VSMCs cloned with empty vector (pC) under basal, serum-stimulated, and hypoxic conditions. This decrease in proliferation correlated with TP-induced HO-1 expression and was reversed by inhibitors of either TP or HO activity. Furthermore, in C2, the cyclin-dependent kinase inhibitor (p27KIP1) was much more abundant than in pC, and the cell cycle was arrested at the G1 phase. TP or HO activity inhibitors decreased p27KIP1 expression in C2 to the level seen in pC. Adventitial TP gene delivery significantly reduced neointimal VSMC migration and neointima formation in balloon-injured rat carotid arteries. Conclusions—TP overexpression upregulated HO-1 expression and consequently increased p27KIP1 in cultured VSMCs, and inhibited VSMC migration and proliferation in vitro and in vivo. TP represents a promising target for treating vascular obstructive disease.

Adventitial delivery of platelet-derived endothelial cell growth factor gene prevented intimal hyperplasia of vein graft

BACKGROUND Platelet-derived endothelial cell growth factor (PD-ECGF), also known as thymidine phosphorylase (TP) reportedly inhibits vascular smooth muscle cells (VSMCs) migration and proliferation. We hypothesized that adventitial administration of the PD-ECGF/TP gene will suppress intimal hyperplasia and prevent vein graft failure. METHODS The study used 68 female rabbits. Rabbit jugular vein was autogenously transplanted into carotid artery with a cuff anastomotic technique. To define vascular wall gene transfer efficiency, poloxamer hydrogel (20%) containing plasmid vector encoding the LacZ gene and different concentrations of trypsin (0%, 0.1%, 0.25%, and 0.5%, n = 5 for each group) was applied to the adventitia of the vein graft. Gene transfer efficiency was evaluated 7 days later by X-gal staining. An additional 48 rabbits received poloxamer hydrogel (20%) containing 0.25% trypsin and the human PD-ECGF/TP gene, LacZ gene, or saline. Intima thickness was evaluated at 2 and 8 weeks after grafting (n = 8 for each group at each time point). Transgene expression was examined by reverse transcriptase-polymerase chain reaction, immunoblotting assay, and immunohistochemical staining. Immunohistochemical staining was also used to determine VSMC proliferation, heme oxygenase-1 expression, and macrophage infiltration. RESULTS Incorporation of trypsin into the poloxamer hydrogel significantly increased vessel wall gene transfer. Trypsin at 0.25% and 0.5% resulted in higher gene transfer at the same level without effecting intimal hyperplasia and inflammation; thus, trypsin at 0.25% concentration was used for subsequent experiments. Compared with the LacZ and saline groups, grafts receiving the PD-ECGF/TP gene significantly reduced intimal thickness at 2 and 8 weeks after treatment. The ratio of proliferative VSMC was lower in PD-ECGF/TP treated grafts. Histologic examination of the PD-ECGF/TP transgene grafts demonstrated high expression of heme oxygenase-1, which has been reported to inhibit VSMC proliferation, suggesting that heme oxygenase-1 may be important in the inhibition effect of PD-ECGF/TP on VSMC. No neoplastic or morphologic changes were found in the remote organs. CONCLUSIONS A safe and highly efficient gene transfer method was developed by using poloxamer hydrogel and a low concentration of trypsin. Neointimal hyperplasia was significantly reduced by adventitial application of the PD-ECGF/TP gene to the vein graft. Our data suggest that adventitial delivery of the PD-ECGF/TP gene after grafting may be promising method for preventing vein graft failure.

Long‐term effect of gene therapy for chronic ischemic myocardium using platelet‐derived endothelial cell growth factor in dogs

We previously reported the 2‐week benefits of platelet‐derived endothelial cell growth factor (PD‐ECGF) gene therapy in chronically ischemic myocardium. However, the long‐term effects and safety using this gene have not been reported.

Our experiences for off-pump coronary artery bypass grafting to the circumflex system

BACKGROUND Complete revascularization has been difficult in off-pump coronary artery bypass grafting (OPCAB). Hemodynamic deterioration often prevents access to the circumflex territory. This study presents instrumentation for accessing the circumflex territory, and our clinical experience. METHODS From August 1999 through December 2002, 140 patients underwent OPCAB via sternotomy in our institution. The 114 requiring reconstruction of the circumflex artery are the subjects of this study. There were no exclusion criteria. A series of techniques and instruments were developed to provide access to the circumflex area while hemodynamic stability was preserved, including the left pericardial traction technique, compression of the right pericardium, a right sternal retractor, and a type of shunt tube. RESULTS Patients received an average of 3.2 grafts (range, 2 to 6). Complete revascularization was achieved in 95% of the cases. Complications included respiratory insufficiency (0.8%), renal dysfunction (7%), and sternal wound infection (0.8%). Blood transfusions were required in 10 patients (8%). No patient suffered perioperative myocardial infarction or stroke. No operation was converted to cardiopulmonary bypass. There was no operative death. Predischarge angiography demonstrated a 99% patency rate. CONCLUSIONS With our techniques and instruments, off-pump coronary revascularizaion of the circumflex area may be performed safely to achieve complete revascularization. Early clinical results are excellent, but long-term longitudinal follow-up is required to assess the future effectiveness of OPCAB procedure with our techniques.

Thrombosed abdominal aortic aneurysm associated with an extensively "shaggy" aorta repaired anatomically via a thoracoabdominal approach with supraceliac aortic clamping: report of a case.

A 76-year-old man with a history of multiple laparotomies and severe coronary artery disease was referred to our hospital after the sudden development of pain and numbness in the lower extremities. Computed tomography showed a thrombosed abdominal aortic aneurysm and diffuse aortic atherosclerosis; compatible with a “shaggy aorta.” A good response to thrombolytic therapy permitted elective scheduling of abdominal aortic surgery after coronary artery bypass grafting. We operated via an extended left retroperitoneal approach through a thoracoabdominal incision. Epiaortic ultrasonography revealed that only the supraceliac aorta was free of mobile thrombi and had minimal plaque; we therefore placed a proximal aortic cross-clamp there. Anatomic aortic reconstruction was then performed successfully using an aorto-biiliac graft to restore adequate distal blood flow. There were no vital-organ ischemic complications, and the postoperative course was satisfactory.

Midterm Results of Mitral Valve Repair with a Rigid Ring

当施設において過去5年間にrigid ringを使用した僧帽弁形成術63例を対象に術後僧帽弁閉鎖不全症(MR)およびleft ventricular diastolic dimension (LVDd)を追跡し,rigid ring使用の是非を検証した.術式は腱索再建20例,quadrangular resection42例,ring annuloplastyのみ15例であり,これら全例にCarpentier-Edwards ringを使用した.これらの症例において手術成績,手術前後のMR,LVDdを追跡し,平均追跡期間41.2ヵ月までの再手術率,弁関連合併症回避率,生存率につき検討を行った.また人工弁輪サイズによる遠隔期でのMR制御能およびring縫着後の弁口面積についても検討した.結果として,入院死亡はなく,心エコー上,退院時II度以上のMR残存例は認めなかった.MRは術前平均3.13度から術後0.28度へと減少し,LVDdは術前平均58.4±6.71mmから術後平均48.7±6.3mmへと減少した.術後平均追跡期間41.2ヵ月での再手術例は2例(32%),mortalityは3/63,4.8%であり,死亡例はいずれも他疾患によるものであった.術前と術後遠隔期のMR(0～4度)を人工弁輪サイズ30mm以上のL群と28mm以下のS群で比較すると,L群で術前3.17度,術後遠隔期0.42度,S群で術前3.13度,術後遠隔期0.25度であり,S群において遠隔期のMR制御能は良好であった.Rigid ring縫着後の弁口面積を心エコーで調べた結果,CE26で平均2.85±0.62cm2,CE28で2.95±0.38cm2,CE30で3.09±0.49cm2であり,臨床上MSが問題となった症例は認めなかった.MRに対する残存MRを制御することを目的にrigid ringを使用した弁形成術の成績は良好であった.

Clinical Result of Consecutive 65 Cases of Minimally Invasive Direct Coronary Artery Bypass Grafting

1999年5月から2002年5月まで当科で行ったMIDCAB65例について検討した.年齢は29～90歳,平均70.9歳,男性51例,女性14例であった.MIDCABの適応となった理由は左前下行枝1枝病変46例,high riskを伴う多枝病変でLAD以外への血行再建が不要と判断されたもの19例であった.手術は全例左前胸部小切開でアプローチし,症例に応じて第4あるいは第5肋間開胸とした.全吻合箇所は67ヵ所で,LIMA-LAD1枝が63例,RA,IEAをcomposite graftとし2ヵ所に吻合したものが2例であった.胸骨正中切開,体外循環への移行はなかった.完全血行再建率は72.3%,ICU stayは1日が63例,透析患者2例が2日であった.全例12時間以内に抜管し,術後合併症は創感染を1例認めたが,脳合併症や呼吸器合併症など多臓器合併症はなく,死亡もなかった.退院前の第1回目に造影結果では,1例にstring様の狭窄がみられたが,それ以外は良好に開存しており開存率は98.5%であった.術後から現在まで(3～41ヵ月)の心事故は狭心症2例,PTCA1例,心房細動4例,心不全0例であり,死亡は認めていない.手術成績からみてわれわれが行ってきたMIDCABの適応,術式は妥当であると考えられる.