Masatsugu Ohtsuki

Diagnostic utility of tenascin‐C for evaluation of the activity of human acute myocarditis

Tenascin‐C (TN‐C) is an extracellular matrix protein that is expressed transiently in close association with tissue remodelling in various body sites. In the heart, TN‐C is only present during early stages of development, is not expressed in the normal adult, but reappears in pathological states. The purpose of this study was to analyse the expression of TN‐C in myocardial tissue from myocarditis patients, and to evaluate the diagnostic value of immunostaining for TN‐C in the assessment of inflammatory activity in biopsy specimens. A total of 113 biopsy specimens obtained from 32 patients with a clinical diagnosis of acute myocarditis were examined by immunohistochemistry and in situ hybridization for TN‐C. The immunostaining was semi‐quantified and compared with histological diagnosis according to the Dallas criteria. Furthermore, serial biopsies from 22 patients were taken during convalescence, and sequential changes in TN‐C levels were analysed. Expression of TN‐C was specifically detected in endomyocardial biopsy specimens from patients with active‐stage inflammation, and disappeared in healed stages. The degree of expression of TN‐C correlated with the severity of histological lesions. These data suggest that TN‐C reflects disease activity in cases of human myocarditis. Immunostaining for TN‐C could enhance the sensitivity and accuracy of diagnosis using biopsy specimens. Copyright

Changes in the peripheral eosinophil count in patients with acute eosinophilic myocarditis

In many cases, the diagnosis of eosinophilic myocarditis is suggested by an elevated peripheral blood eosinophil count. However, no detailed studies have been performed on the sequential changes in the initial peripheral blood eosinophil count over the course of the disease. We measured the peripheral blood eosinophil count at the time of presentation in eight patients with eosinophilic myocarditis proven by endomyocardial biopsy and intermittently thereafter. The eosinophil count at the time of onset was ≪500/mm3 in four patients, ≫500/mm3 but ≪1 000/mm3 in three patients, and ≧1 000/mm3 in one patient. In three of the four patients with an initial eosinophil count of ≪500/mm3, an increase to ≧500/mm3 occurred 7–12 days after the onset. The remaining patient did not develop peripheral eosinophilia. In conclusion, in the early stage of eosinophilic myocarditis, peripheral hypereosinophilia is not present initially in some patients, and may not develop during the course of the illness in a subset of these patients.

Angiotensin converting enzyme 2 gene expression increased compensatory for left ventricular remodeling in patients with end-stage heart failure

It has been reported that angiotensin converting enzyme (ACE) 2, a homologue of ACE, has direct effects on cardiac function. However, the role of ACE2 in the development of human heart failure is not fully understood. We evaluated the expression of the ACE2 gene by means of real-time RT-PCR in myocardium from 14 patients with end-stage heart failure. The amount of ACE2 mRNA positively correlated with left ventricular (LV) end-diastolic diameter (r(2)=0.56, p<0.01) but did not significantly correlate with LV ejection fraction or plasma brain natriuretic peptide levels. In conclusion, our data show that the up-regulation of the ACE2 gene in the LV myocardium of patients with severe heart failure was associated with the degree of LV dilatation and may thereby constitute an important adaptive mechanism to retard the progression of adverse LV remodeling.

Efficacy of Atorvastatin Therapy in Ischaemic Heart Disease – Effects on Oxidized Low-density Lipoprotein and Adiponectin

The lipid-lowering and anti-atherosclerotic effects of atorvastatin (10 mg/day) were investigated by measuring changes in the levels of oxidized low-density lipoprotein (LDL), serum lipids (total cholesterol [TC], LDL-cholesterol [LDL-C] and triglycerides [TG]), and in the protein adiponectin. This was undertaken in 22 patients with ischaemic heart disease and serum LDL-C levels > 100 mg/dl. After 3 months of therapy, atorvastatin significantly decreased serum lipids, oxidized LDL was reduced from 457.0 ± 148.6 to 286.9 ± 88.5 nmol/l, and adiponectin increased from 9.7 ± 7.4 to 13.9 ± 9.98 μg/ml. No significant correlation was observed between adiponectin and LDL-C, TG and high-density lipoprotein cholesterol. Atorvastatin therapy was not associated with side-effects, such as myalgia and gastrointestinal disorders, and did not give abnormal laboratory test results. It is concluded that atorvastatin decreases serum lipid and oxidized LDL levels, and increases adiponectin levels in patients with ischaemic heart disease.

Role of myocardial interstitial edema in conduction disturbances in acute myocarditis

The presence of myocardial interstitial edema in acute myocarditis (AM) leads to thickening of the ventricular wall, and conduction disturbances, such as complete atrioventricular block (CAV), also frequently develop. This study was undertaken in order to clarify the relationship between conduction disturbances and myocardial interstitial edema in AM. The subjects comprised 50 patients with acute lymphocytic myocarditis. Based on the results of echocardiographic examinations during the acute stage, the patients were divided into a hypertrophy group (n = 29) in which the sum of the thickness of the interventricular septum and left ventricular (LV) posterior wall was ≥24 mm, and a non-hypertrophy group (n = 21) in which the sum of these parameters was <24 mm. Right ventricular endomyocardial biopsies were performed in the acute stage and the degree of interstitial edema was scored histologically. Left ventricular wall thickness and QRS duration in the acute stage were 27.7 ± 3.6 mm and 124.1 ± 29.6 ms, respectively, in the hypertrophy group, and 19.9 ± 2.4 mm (P < 0.001) and 98.6 ± 21.7 ms (P < 0.01) in the non-hypertrophy group. Complete atrioventricular block was found in 13 of 29 cases (45%) in the hypertrophy group and two of 21 cases (10%) in the non-hypertrophy group (P < 0.01). Myocardial interstitial edema was scored at 1.3 ± 0.8 points in the hypertrophy group and 0.8 ± 0.6 points in the non-hypertrophy group (P < 0.05). Left ventricular wall thickness and QRS duration in the convalescent stage decreased to 21.1 ± 2.6 mm (P < 0.0001) and 97.1 ± 17.4 ms (P < 0.01) in the hypertrophy group, respectively. Only one case (4%) in the hypertrophy group continued to show CAV during the convalescent stage (P < 0.05). The results of this study suggest that myocardial interstitial edema is implicated in the conduction disturbances that occur in AM.

Successful high-dose intravenous immunoglobulin therapy for a patient with fulminant myocarditis.

A 45-year-old man developed fulminant myocarditis for which ventricular assist devices (intra-aortic balloon pumping and percutaneous cardiopulmonary support) were required for hemodynamic support. Echocardiography showed left ventricular akinesis and, since no improvement was noted on the following day, immunoglobulin (70 g/day for 2 days) was added to the therapy. The left ventricular ejection fraction increased to 25% and 40% at 12 and 36 h, respectively, representing a marked improvement in wall motion within a very short period. An endomyocardial biopsy specimen revealed focal lymphomononuclear infiltrate with adjacent myocytolysis, and acute lymphocytic myocarditis was diagnosed. Two days after administration of immunoglobulin, the serum level of interleukin-6 decreased rapidly from 180 to 5.9 pg/ml. In this patient, cardiac function improved immediately after immunoglobulin administration, suggesting the usefulness of this therapy. Three years after the diagnosis the patient is in good health, with steady normal left ventricular ejection fraction. We conclude that there are cases of acute myocarditis in which high-dose intravenous immunoglobulin therapy is effective.

Isolation of a full-length cDNA clone for human GTP cyclohydrolase I type 1 from pheochromocytoma

Although the existence of three different cDNA forms of human GTP cyclohydrolase I (GCH I) have been reported (Togari et al., 1992), the full-length sequence of any human GCH I cDNA involving poly (A) tail has not yet been documented. In the present study, we first isolated a full-length cDNA clone encoding human GCH I type 1 from human pheochromocytoma cDNA library. The length of the cDNA insert was 2,921 base pairs including poly (A) tail. RNA blot analysis showed a single niRNA species of 4.0kb in human pheochromocytoma tissue.

Significance of transient left ventricular wall thickening in acute lymphocytic myocarditis

Transient left ventricular (LV) wall thickening is observed in patients with acute lymphocytic myocarditis. The present study was undertaken to clarify the significance of transient LV wall thickening in patients with this disease. The subjects comprised 25 patients with acute lymphocytic myocarditis. Echocardiography was used to measure the thickness of the interventricular septum (IVS) and the LV posterior wall (PW) at four time points after myocarditis onset – namely, on days 1–3, 6–8, 13–15, and 28–30 – to clarify the timing and frequency of wall thickening. The 25 patients were divided into a fulminant myocarditis group (n = 14) and a nonfulminant myocarditis group (n = 11), and the relationship between LV wall thickening and myocarditis severity was investigated. Left ventricular wall thickening was greatest on days 1–3 after myocarditis onset (IVS: 13.3 ± 3.2 mm; PW: 12.1 ± 2.6 mm), with this finding being noted in 14 of the 25 cases (56%). By days 6–8, the thickness of IVS had virtually normalized to 10.6 ± 1.6 mm (P < 0.0001) and that of PW to 10.2 ± 1.4 mm (P = 0.0006). The thickness of the IVS and PW on days 1–3 after myocarditis onset were 14.6 ± 3.7 and 13.0 ± 2.9 mm, respectively, in the fulminant group (P = 0.014), and 11.5 ± 0.9 and 10.9 ± 1.4 mm, respectively, in the nonfulminant group (P = 0.039). In lymphocytic myocarditis, LV wall thickening is greatest on days 1–3 after myocarditis onset and improves to near normal by days 6–8. Such transient LV wall thickening occurs in approximately 50% of cases. Left ventricular wall thickening was more marked in the fulminant compared with the nonfulminant group.

2,4-Diamino-6-hydroxypyrimidine (DAHP) suppresses cytokine-induced VCAM-1 expression on the cell surface of human umbilical vein endothelial cells in a BH4-independent manner

2,4-Diamino-6-hydroxypyrimidine (DAHP) is considered a specific inhibitor of BH(4) biosynthesis and is widely used in order to elucidate the possible biological function of BH(4) in various cells. In the present study, we found that both the synthesis of tetrahydrobiopterin (BH(4)) and expression of vascular cell adhesion molecule 1 (VCAM-1) were increased in human umbilical vein endothelial cells (HUVEC) treated with proinflammatory cytokines. Thus we examined the effects of DAHP to clarify whether BH(4) might be involved in the expression of VCAM-1 in HUVEC. DAHP reduced the levels of both BH(4) and VCAM-1 induced by TNF-alpha and IFN-gamma. However, the dose-response curves of DAHP for the suppression of the VCAM-1 level and that of BH(4) level were markedly different. Supplementation with sepiapterin failed to restore the depressed VCAM-1 level, although it completely restored the BH(4) level. Furthermore, DAHP significantly reduced the VCAM-1 level under the experimental conditions using TNF-alpha alone, which failed to induce BH(4) production. Taken together, these results indicate that DAHP inhibited the expression of VCAM-1 in a BH(4)-independent manner in HUVEC. In the present study, we also found that DAHP significantly suppressed the accumulation of cytokine-induced NF-kappaB (p65) in the nucleus as well as the mRNA levels of VCAM-1 and GTP cyclohydrolase I (GTPCH), the rate-limiting enzyme of BH(4) synthesis. The data obtained in this study suggest that DAHP reduced VCAM-1 and GTPCH protein synthesis at least partially via suppressing the NF-kappaB level in the nucleus of HUVEC.

Large-scale team-based learning for interprofessional education in medical and health sciences

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