Yasuyuki Bito

Calorie Restriction Improves Cardiovascular Risk Factors via Reduction of Mitochondrial Reactive Oxygen Species in Type II Diabetic Rats

Uncoupling protein 2 (UCP2) is an important regulator of intracellular reactive oxygen species (ROS) production. We determined the effects of calorie restriction (CR) on the dynamic aspects of mitochondrial ROS production, UCP2, and the nitric oxide (NO)-cGMP pathway in the cardiovascular tissues of type II diabetic Otsuka Long-Evans Tokushima Fatty (OLETF) rats. Some rats were on restricted diets (30% reduction from free intake) from age 29 to 42 weeks. Blood glucose, hemoglobin A1c, plasma levels of free fatty acid, triacylglycerol, and plasminogen activator inhibitor-1 in OLETF rats were significantly higher than those in nondiabetic control [Long-Evans Tokushima Otsuka (LETO)] rats at 29 weeks. Mitochondrial ROS production and UCP2 expression significantly increased in the heart and aorta of OLETF rats compared with those in LETO rats. A fibrogenic growth factor, transforming growth factor (TGF)-β1 in the coronary vessels, endothelial nitric-oxide synthase, and aortic nitrotyrosine were increased in OLETF rats at 42 weeks. In contrast, an index of the NO-cGMP pathway, phosphorylated vasodilator-stimulated phosphoprotein, and superoxide dismutase activity in the aorta were significantly diminished. The relationship between UCP2 and ROS production in the cardiovascular function of diabetic rats being fed a calorie-restricted diet is unknown. These abnormalities in OLETF rats were reversed to normal levels by CR. CR significantly improved the NO-cGMP pathway via normalizing ROS generation in OLETF rats. A decrease in UCP2 expression by CR may be a compensatory mechanism to counteract decreased intracellular oxidative stress. The data suggest that CR may prevent cardiovascular tissues from oxidative stress provoked by diabetes mellitus.

Supplementation of α-tocopherol improves cardiovascular risk factors via the insulin signalling pathway and reduction of mitochondrial reactive oxygen species in type II diabetic rats

This study determined the effects of α- and γ-tocopherol supplementation on metabolic control and oxidative stress in type 2 diabetic Otsuka Long–Evans Tokushima Fatty (OLETF) rats. Blood glucose, haemoglobin A1c (HbA1c), urinary protein, plasma free fatty acid, triacylglycerol and plasminogen activator inhibitor-1 (PAI-1) levels in OLETF rats were significantly higher than in non-diabetic control Long–Evans Tokushima Otsuka (LETO) rats. α-Tocopherol inhibited the increase in urinary protein, blood glucose, HbA1c and PAI-1 levels, but γ-tocopherol did not. Plasma and hepatic lipid peroxidation and hepatic steatosis were increased in OLETF rats. α-Tocopherol decreased lipid peroxidation. Mitochondrial reactive oxygen species production and uncoupling protein 2 (UCP2) expression were significantly increased in the heart and aorta of OLETF rats compared with LETO rats. Endothelial NO synthase and aortic nitrotyrosine were increased in OLETF rats. In contrast, the expression of phosphorylated vasodilator-stimulated phosphoprotein and glucose transporter 4 in the aorta was significantly decreased in OLETF rats. These abnormalities were reversed by α-tocopherol. These findings suggest that α-tocopherol may prevent cardiovascular tissues from oxidative stress and insulin signalling disorder resulting from diabetes mellitus.

Mitral valve repair for atrial functional mitral regurgitation in patients with chronic atrial fibrillation

OBJECTIVES Atrial functional mitral regurgitation (MR) has been recently described in patients with chronic atrial fibrillation (AF). However, the results of surgical mitral valve (MV) repair for this type of MR have not been comprehensively reported. Our study aimed to address this deficiency. METHODS We retrospectively studied 10 chronic AF patients who underwent MV repair for atrial functional MR with normal left ventricular dimension and preserved left ventricular systolic function. All patients had chronic heart failure (HF) symptoms and at least one prior admission for HF complicated by severe MR. RESULTS Ring annuloplasty was performed in all patients; the median ring size was 26 mm (range, 26-30 mm). Concomitant tricuspid valve repair was undertaken in all patients. Preoperatively, left atrial (LA) diameter on the parasternal long-axis view, LA volume index and mitral annular diameter were 52 ± 9 mm, 72 ± 26 ml/m(2) and 33 ± 4 mm, respectively. There was no mortality and no re-admission due to HF during follow-up (range, 10-52 months). MR at the most recent examination was mild or improved in degree in all patients. The LA volume index decreased from the preoperative period, measuring 48 ± 17 ml/m(2) at the most recent period (P = 0.03). The New York Heart Association functional class dramatically improved from the preoperative period to the most recent period (from 3.0 ± 0.7 to 1.2 ± 0.4, P < 0.0001). CONCLUSIONS Our results suggest that MV repair leads to reductions in MR, LA size and HF symptoms, and that it may prevent future HF events in patients with atrial functional MR.

Mitral valve replacement for extensive calcification: half and half technique

A 50-year-old woman who had been undergoing hemodialysis for 18 years underwent mitral valve replacement because of mitral valve stenosis. Her mitral valve leaflet and annulus were highly calcified, and it was impossible to remove the posterior leaflet from the ventricular wall. At the time of surgery, noneverted horizontal mattress sutures were placed from the left ventricle to the left atrium on the anterior half of the mitral annulus and everted horizontal mattress sutures on the left atrial wall close to the calcified posterior annulus. A 25-mm St. Jude valve was seated successfully at a supra-annular position. The St. Jude valve is suitable for this technique because its leaflets protrude less into the left ventricle.

Which valve and which size should we use in the valve-on-valve technique for re-do mitral valve surgery?

The valve-on-valve (VOV) technique is that a mechanical valve is implanted on the sewing cuff of the previous bioprosthesis after removing degenerated leaflets. We conducted an in vitro study to determine the size-match of the valves for VOV technique. The Carpentier-Edwards pericardial (CEP) valve and Mosaic valve were used. We measured the inner diameter of the bioprosthesis after removing the leaflets. We investigated five mechanical mitral valves and two mechanical aortic valves (inverted use). The mitral valves used in this study were the ATS valve (ATS), the CarboMedics standard valve (CMS), the CarboMedics OptiForm valve (CMO), the On-X valve, and the St Jude valve (SJM). Two aortic mechanical valves, CarboMedics and St Jude Regent valves, were investigated for inverted use. After removing the tissue leaflets, the inner diameter of the Mosaic valve was 3 mm smaller than that of the CEP valve even in the same catalogue labeling size. The outer diameters of the housing of the ATS, CMS, CMO, On-X, and SJM valves of the same catalogue size (25 mm) were 25.7, 25.8, 22.0, 25.0, and 23.2 mm, respectively. SJM and CMO valves are the favorite mechanical valve for the VOV technique in terms of the profile and size-match.

A Surgical Case of Expanding Bilateral Coronary Aneurysms Regarded as Immunoglobulin G4-Related Disease

A 69-year–old man was referred to our department for surgical treatment of bilateral giant coronary artery aneurysms. He had no apparent clinical factors associated with atherosclerosis, such as diabetes mellitus, hyperlipidemia, or hypertension. Physical examination revealed no abnormalities. His medical history included malignant lymphoma that had been treated with chemotherapy and radiation therapy at the age of 60 years. He was also diagnosed with a plasma cell tumor in his tonsils at the age of 68 years. Just before treatment for this tumor, he developed sudden-onset myocardial infarction. Coronary angiography revealed 2 giant coronary aneurysms; one presented as a broad aneurysmal change of the right coronary artery (Figure 1A and Movie I in the online-only Data Supplement), and the other was located from the left main coronary artery to the left anterior descending artery (Figure 1B and Movie II in the online-only Data Supplement). On the basis of subsequent computed tomography, the maximum diameters of the right and left coronary aneurysms were 40 and 25 mm, respectively (Figure 2). Laboratory examination showed that the serum immunoglobulin …

Clinical management of lower limb ischemia secondary to a persistent sciatic artery aneurysm: Report of a case

A persistent sciatic artery (PSA) is a rare congenital malformation, frequently complicated by atherosclerotic changes such as aneurysmal formation. Optimal treatment is dependent on the individual situation. We report a case of a PSA aneurysm complicated by lower limb ischemia. Graft interposition with distal balloon angioplasty and thrombectomy from the posterior transgluteal approach was performed successfully, without any complications.

Successful surgical treatment of a mycotic right coronary artery aneurysm complicated by a fistula to the right atrium

We reported successful surgical treatment of a mycotic right coronary artery aneurysm complicated by a fistula to the right atrium in a 60-year-old man admitted to hospital because of acute worsening of renal function and erythroderma. After admission, he suffered from methicillin-resistant Staphylococcus aureus septicemia. Despite administration of vancomycin hydrochloride, a low-grade fever persisted. Subacute cardiac tamponade occurred three months after admission, and acute inferior wall myocardial infarction occurred two weeks after pericardial drainage. An emergent coronary angiography demonstrated a large saccular aneurysm of the right coronary artery forming a fistula to the right atrium and obstruction of the distal right coronary artery. We emergently resected the aneurysm including the right atrial wall and repaired the defect in the right atrium. Pathological examination of the aneurysmal wall revealed its mycotic nature; the postoperative course was uneventful.

Impact of non-di-(2-ethylhexyl)phthalate cardiopulmonary bypass tubes on inflammatory cytokines and coagulation-fibrinolysis systems during cardiopulmonary bypass

Di-(2-ethylhexyl)phthalate (DEHP), an excellent plasticizer for poly(vinyl chloride) (PVC), is a known endocrine-disrupting chemical. This study was designed to investigate whether a new non-DEHP bilayer tube reduced the release of DEHP, suppressed inflammatory cytokines, and altered coagulation-fibrinolysis systems. Sixteen patients undergoing coronary artery bypass grafting (CABG) were randomly assigned to the non-DEHP bilayer group (group B, n = 8), or the noncoated PVC group (group N, n = 8). The level of DEHP in the blood was measured before and after cardiopulmonary bypass (CPB). The levels of interleukin-6 (IL-6), D-dimer, and thrombin-antithrombin complex (TAT) were also measured at six points during and after CPB. DEHP was significantly lower in group B (472 ± 141 ng/ml) after CPB compared with group N (2094 ± 1046 ng/ml). The IL-6 level was significantly lower in group B (151 ± 131 pg/ml) than group N (206 ± 224 pg/ml) 180 min after protamine administration. The D-dimer level was significantly lower in group B 60 min after protamine administration (6.2 ± 2.4 μg/ml in group B vs 10.4 ± 4.5 μg/ml in group N) and 180 min after protamine administration (4.4 ± 0.7 μg/ml in group B vs 7.3 ± 2.7 μg/ml in group N). Group B had a tendency toward reduced postoperative bleeding compared with group N at any time. The bilayer tube was superior to the noncoated tube in terms of the inhibition of DEHP release, inflammatory cytokines, and the fibrinolysis system.

Di(2-Ethylhexyl) Phthalate Exposure during Cardiopulmonary Bypass

Di(2-ethylhexyl) phthalate is an excellent plasticizer for polyvinyl chloride but a known endocrine disrupting chemical. To investigate whether tubing containing no diethylhexyl phthalate reduces the overall extraction of this plasticizer during cardiopulmonary bypass, 16 patients undergoing coronary artery bypass grafting were randomly divided into 2 groups of 8 each. Group A had tubing containing diethylhexyl phthalate in the circuit, and group B had no diethylhexyl phthalate in the tubing. The plasma diethylhexyl phthalate level at the end of cardiopulmonary bypass was significantly increased compared to before anesthesia in both groups (group A: 103 ± 60 to 2,094 ± 1,046 ng·mL−1; group B: 135 ± 60 to 472 ± 141 ng·mL−1), and it was significantly higher in group A than group B. This study demonstrates that using tubing free from diethylhexyl phthalate significantly reduces the release of this agent during cardiopulmonary bypass, which may minimize exposure to diethylhexyl phthalate.