Shinichi Nunoda

Quantitative approach to the histopathology of the biopsied right ventricular myocardium in patients with diabetes mellitus

SummaryFor the purpose of studying the clinicopathology of the biopsied myocardium in patients with diabetes mellitus, the diameter of right ventricular myocardial cells and diffuse perimysial fibrosis of biopsied myocardium were measured quantitatively. Seven healthy controls and nine diabetic patients without hypertension or coronary arterial disease were subjected to this study. The degree of diabetic complications was mild to moderate. The diameter of myocardial cells was measured and the degree of diffuse perimysial fibrosis was assessed by the point-counting method using a square grid, in which the distance between the points was 10 µm. Over 2000 points which lay on the longitudinally cut myocardial cells and on the interstitial fibrosis stained by the Mallory-Azan method were measured. Percentage fibrosis was calculated according to the formula: percentage fibrosis=(points lying on the interstitial fibrosis)/[(points lying on the myocardial cell)+(points lying on the interstitial fibrosis)] × 100. The results were as follows. The mean diameter of right ventricular myocardial cells in patients with diabetes mellitus was significantly larger than that of controls (P<0.01). The percentage fibrosis of diabetic patients was significantly higher than that of controls (P<0.01). There was no significant correlation between the histopathological measurements and clinical features. It is concluded that hypertrophy of myocardial cells and interstitial fibrosis of the myocardium exist even in mild diabetes mellitus.

The Registry Report of Heart Transplantation in Japan (1999–2014)

Postoperative cardiac patients frequently are mildly hypothermic, yet the influence of hypothermia on left ventricular (LV) contractility has received little attention. To study the possible effects of mild hypothermia on LV function, six pigs were placed on partial right ventricular bypass, the hearts were electrically paced to control heart rate, and myocardial temperature was varied between 34 degrees and 38 degrees C. Using two pairs of orthogonally oriented sonomicrometer crystals in the left anterior descending (LAD) and left circumflex (LCX) distributions, we estimated regional work (the area within LV pressure-area loops) over a range of LV preloads. Diastolic function was assessed by measurement of the time constant of LV pressure decay during isovolumic relaxation. Regional work data were expressed as percentages of baseline (38 degrees C and end-diastolic pressure of 10 mm Hg). To control for preload variations, regional work and time constants were calculated from beats with end-diastolic areas within 0.1% of baseline. Regional work (mean +/- SEM) declined from 85.1 +/- 6.7% at 38 degrees C to 31.9 +/- 4.4% at 34 degrees C. Time constants were prolonged from 44.8 +/- 2.5 msec at 38 degrees C to 61.6 +/- 2.7 msec at 34 degrees C. These data demonstrate a marked depression of LV contractility, even at mild levels of hypothermia that may be encountered clinically after cardiac operations.

Dilated cardiomyopathy‐associated BAG3 mutations impair Z‐disc assembly and enhance sensitivity to apoptosis in cardiomyocytes

Dilated cardiomyopathy (DCM) is characterized by dilation of left ventricular cavity with systolic dysfunction. Clinical symptom of DCM is heart failure, often associated with cardiac sudden death. About 20–35% of DCM patients have apparent family histories and it has been revealed that mutations in genes for sarcomere proteins cause DCM. However, the disease‐causing mutations can be found only in about 17% of Japanese patients with familial DCM. Bcl‐2‐associated athanogene 3 (BAG3) is a co‐chaperone protein with antiapoptotic function, which localizes at Z‐disc in the striated muscles. Recently, BAG3 gene mutations in DCM patients were reported, but the functional abnormalities caused by the mutations are not fully unraveled. In this study, we analyzed 72 Japanese familial DCM patients for mutations in BAG3 and found two mutations, p.Arg218Trp and p.Leu462Pro, in two cases of adult‐onset DCM without skeletal myopathy, which were absent from 400 control subjects. Functional studies at the cellular level revealed that the DCM‐associated BAG3 mutations impaired the Z‐disc assembly and increased the sensitivities to stress‐induced apoptosis. These observations suggested that BAG3 mutations present in 2.8% of Japanese familial DCM patients caused DCM possibly by interfering with Z‐disc assembly and inducing apoptotic cell death under the metabolic stress. 32:1481–1491, 2011. ©2011 Wiley Periodicals, Inc.

Weekly Variation of Home and Ambulatory Blood Pressure and Relation Between Arterial Stiffness and Blood Pressure Measurements in Community-Dwelling Hypertensives

Although blood pressure (BP) is a major determinant of pulse wave velocity (PWV), some treatments have independent effects on BP and arterial stiffness. Although both ambulatory BP (ABP) and self-measured BP at home (HBP) have become important measures for the diagnosis and management of hypertension, single day recordings may be insufficient for a proper diagnosis of hypertension or the evaluation of treatment efficacy. To evaluate weekly variations in BP using 7-day HBP and 7-day ABP monitoring and to determine the relation between arterial stiffness and BP measurements in community-dwelling patients with hypertension. We enrolled 68 community-dwelling hypertensive subjects in this study. Significant weekly variations in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were found in the awake ABP data (p < .01, respectively), while no significant weekly variations in the asleep ABP or the morning and evening HBP data were observed. In untreated subjects, significant correlations were obtained between the brachial-ankle PWV and the average awake SBP, the average asleep SBP and the average SBP measured by HBP in the evening. In treated subjects, only the average SBP measured by HBP in the morning was significantly correlated with the baPWV. Differences in the weekly variations in BP were observed between HBP and ABP monitoring. In addition, the morning systolic HBP was not correlated with arterial stiffness in untreated subjectswith hypertension but was correlated in treated subjects. Relations between the morning HBP and arterial stiffness might be attributed to morning surges in BP and/or trough levels of antihypertensive drugs.

Coronary angiographic characteristics in Japanese patients with heterozygous familial hypercholesterolemia

Coronary angiographic findings were analyzed in 51 consecutive patients (36 males and 15 females) with heterozygous familial hypercholesterolemia (FH) and 279 consecutive patients (216 males and 63 females) without FH (non-FH). The coronary stenosis index and over 75% stenosis vessel subset were almost three times as high in the FH group. The incidence of myocardial infarction was almost twice as high in the FH group. Levels of total cholesterol and its lipoprotein fractions, except HDL-cholesterol, were almost twice as high in the FH group. In the FH group aged under 50 years, the two parameters of coronary angiogram and the incidence of myocardial infarction were significantly higher in males than in females. However, in the group aged over 50 years, all three parameters were not significantly different between those in males and females. The level of HDL-cholesterol was significantly lower in males than in females. A significantly higher incidence (18%) of coronary ectasia was observed in the FH group compared with the incidence (2%) in non-FH. All patients with coronary ectasia were males, except one female with FH. On comparison of the males among the FH patients with those among the non-FH patients matched for total cholesterol, age and other risk factors, the FH patients were associated with a significantly higher degree of coronary atherosclerosis and lower level of HDL-cholesterol. Seven FH patients with a normal coronary angiogram were observed. However, any factors as regards age, total cholesterol, HDL-cholesterol and Achilles tendon thickness failed to distinguish between the FH patients with a normal coronary angiogram and those without.(ABSTRACT TRUNCATED AT 250 WORDS)

Left ventricular endomyocardial biopsy findings in patients with essential hypertension and hypertrophic cardiomyopathy with special reference to the incidence of bizarre myocardial hypertrophy with disorganization and biopsy score

SummaryTo investigate whether bizarre myocardial hypertrophy with disorganization (BMHD) is characteristic of hypertrophic cardiomyopathy (HCM), the histopathology of the biopsied left ventricular myocardium in 18 patients with essential hypertension (HT) and 14 patients with HCM was studied. A “biopsy score” was devised for a more quantitative evaluation of the BMHD and a comparative study on the biopsy score of the left ventricular biopsied specimen was also performed. The patients with HT were judged to be in stages I or II of the WHO criteria and had a history of hypertension of more than 5 years. The BMHD was defined as myocardial cells showing hypertrophy, disorganization, and bizarre nuclei. “Disorganization” of myocardial cells was distinguished both by the terminology and histopathological characteristics from “disarrangement” of myocardial cells. The biopsy score employed four factors and was determined according to the following formula: Biopsy score = hypertrophy of myocardial cells + (disorganization of myocardial cells) ×2+ bizarre nuclei + whorling of muscle bundles. Both the hypertrophy and the disorganization of myocardial cells were regarded as essential conditions indicating the presence of BMHD. The BMHD was found in 2 of 18 patients with HT (11%) and in 10 of 14 patients with HCM (71%) in the left ventricular biopsied specimens (P<0.005). However, “disarrangement” of myocardial cells was found in 13 of 18 HT patients (72%) and in 10 of 14 HCM patients (71%) in the left ventricular biopsied specimens, showing no difference between the two groups. The biopsy score in HCM patients was larger than that found in HT patients. It was concluded that BMHD is highly specific (89%) for HCM but that disarrangement of myocardial cells is not specific or diagnostic for HCM. The biopsy score is, therefore, useful for diagnosing HCM histologically and for distinguishing HCM from HT.

A novel β-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model

Mutations in the betaMHC (beta-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the betaMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel betaMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation. To find the mutation responsible, we searched for genomic mutations in 99 unrelated probands with dilated cardiomyopathy and five probands with isolated LVNC, and identified a p.Met531Arg mutation in betaMHC in a 13-year-old girl with isolated LVNC. Next, we generated six lines of transgenic mice carrying a p.Met532Arg mutant alphaMHC gene, which was identical with the p.Met531Arg mutation in the human betaMHC. Among these, two lines with strong expression of the mutant alphaMHC gene were chosen for further studies. Although they did not exhibit the features characteristic of LVNC, approx. 50% and 70% of transgenic mice in each line displayed LVH (LV hypertrophy) by 2-3 months of age. Furthermore, LVD (LV dilation) developed in approx. 25% of transgenic mice by 18 months of age, demonstrating biphasic changes in LV wall thickness. The present study supports the idea that common mechanisms may be involved in LVH and LVD. The novel mouse model generated can provide important information for the understanding of the pathological processes and aetiology of cardiac dilation in humans.

A case of hypereosinophilic syndrome with asymmetric septal hypertrophy

A case of idiopathic hypereosinophilic syndrome (HES) with asymmetric septal hypertrophy (ASH) is described: this is a very rare association. The patient was a 56-year-old male with hypereosinophilia lasting for 10 years. The white blood cell count was 11200/mm3, with 22% eosinophils, and eosinophilic hyperplasia (7.2%) was noted in the bone marrow. A peripheral blood smear showed vacuolated eosinophils with a reduced content of granules. An ultrastructure study of the eosinophils revealed reduced numbers of crystalloid granules which appeared to be dissolving with reversal of normal staining. An echocardiogram and a biventriculoglam indicated ASH with the interventricular septal wall thickness of 2.4 cm and the left ventricular posterior wall thickness of 1.5 cm. Right ventricular endomyocardial biopsy revealed no eosinophilic infiltration, but endocardial thickening, subendocardial fibrosis, hypertrophy, myocytolysis, and fragmentation of muscle bundles were observed.

Donor bone marrow cells are essential for iNKT cell‐mediated Foxp3+ Treg cell expansion in a murine model of transplantation tolerance

Mixed chimerism induction is the most reliable method for establishing transplantation tolerance. We previously described a novel treatment using a suboptimal dose of anti‐CD40 ligand (anti‐CD40L) and liposomal formulation of a ligand for invariant natural killer T cells administered to sub‐lethally irradiated recipient mice after donor bone marrow cell (BMC) transfer. Recipient mice treated with this regimen showed expansion of a Foxp3‐positive regulatory T(Treg) cell phenotype, and formation of mixed chimera. However, the mechanism of expansion and bioactivity of Treg cells remains unclear. Here, we examine the role of donor BMCs in the expansion of bioactive Treg cells. The mouse model was transplanted with a heart allograft the day after treatment. The results showed that transfer of spleen cells in place of BMCs failed to deplete host interferon (IFN)‐γ‐producing CD8+T cells, expand host Ki67+CD4+CD25+Foxp3+ Treg cells, and prolong graft survival. Severe combined immunodeficiency mice who received Treg cells obtained from BMC‐recipients accepted skin grafts in an allo‐specific manner. Myeloid‐derived suppressor cells, which were a copious cell subset in BMCs, enhanced the Ki67 expression of Treg cells. This suggests that donor BMCs are indispensable for the expansion of host bioactive Treg cells in our novel treatment for transplant tolerance induction.

Administration of an Angiotensin-Converting Enzyme Inhibitor Improves Vascular Function and Urinary Albumin Excretion in Low-Risk Essential Hypertensive Patients Receiving Anti-Hypertensive Treatment with Calcium Channel Blockers. Organ-Protecting Effects Independent of Anti-Hypertensive Effect

Abstract Concomitant administration of calcium channel blockers (CCBs) and angiotensin-converting enzyme inhibitors (ACEIs) to hypertensive patients at high risk for cardiovascular disease can prevent cardiovascular disease occurrence, but the effects of this treatment on renal and vascular function in low-risk hypertensive patients are unknown. The current study was an open-label prospective study. Hypertensive patients with no history of cardiovascular disease who had not met their blood pressure (BP) goals with CCB treatment were administered perindopril and followed for 6 months. Both home and office BP were significantly lowered by perindopril administration. The morning/evening (M/E) ratios calculated from home BP were 1.31 and 1.05 for systolic blood pressure (SBP) and diastolic blood pressure (DBP), respectively. When the patients were divided into two groups based on the presence or absence of an anti-hypertensive response, urinary albumin excretion, and cardio ankle vascular index were significantly reduced by perindopril administration in all the subjects, irrespective of the presence or absence of anti-hypertensive reaction. In low-risk hypertensive patients, perindopril improves renal and vascular function probably via its persistent anti-hypertensive effects and the concomitant effects of CCB.