Mika Mori

Molecular genetic epidemiology of homozygous familial hypercholesterolemia in the Hokuriku district of Japan

AIM Familial hypercholesterolemia (FH) is caused by mutations of FH genes, i.e. LDL-receptor (LDLR), PCSK9 and apolipoprotein B (ApoB) gene. We evaluated the usefulness of DNA analysis for the diagnosis of homozygous FH (homo-FH), and studied the frequency of FH in the Hokuriku district of Japan. METHODS Twenty-five homo-FH patients were recruited. LDLR mutations were identified using the Invader assay method. Mutations in PCSK9 were detected by PCR-SSCP followed by direct sequence analysis. RESULTS We confirmed 15 true homozygotes and 10 compound heterozygotes for LDLR mutations. Three types of double heterozygotes for LDLR and PCSK9 were found. No FH patients due to ApoB mutations were found. The incidences of homo-FH and hetero-FH in the Hokuriku district were 1/171,167 and 1/208, respectively. CONCLUSIONS Our observations underlined the value of FH gene analysis in diagnosing homo-FH and confirmed extraordinarily high frequency of FH in the Hokuriku district of Japan.

Comparison of Effects of Pitavastatin and Atorvastatin on Plasma Coenzyme Q10 in Heterozygous Familial Hypercholesterolemia: Results From a Crossover Study

An open, randomized, four‐phased crossover study using 4 mg of pitavastatin or 20 mg of atorvastatin was performed to compare their efficacy and safety, especially regarding plasma levels of coenzyme Q10 (CoQ10) in 19 Japanese patients with heterozygous familial hypercholesterolemia. Pitavastatin and atorvastatin caused significant and almost comparable reductions in serum levels of total cholesterol (−35.4 vs. −33.8%), low‐density lipoprotein cholesterol (−42.8 vs. −40.7%), and triglyceride (−26.1 vs. −29.4%), and significantly increased serum levels of high‐density lipoprotein cholesterol (12.1 vs. 11.4%). Under these conditions, plasma levels of CoQ10 were reduced by atorvastatin (−26.1%, P=0.0007) but not by pitavastatin (−7.7%, P=0.39), although no adverse events or abnormalities of liver and muscle enzyme were observed after either statin treatment. It remains to be seen whether the observed changes in CoQ10 levels are related to the long‐term safety of this drug.

Efficacy and Safety of Coadministration of Rosuvastatin, Ezetimibe, and Colestimide in Heterozygous Familial Hypercholesterolemia

Aggressive low-density lipoprotein (LDL) cholesterol-lowering therapy is important for high-risk patients. However, sparse data exist on the impact of combined aggressive LDL cholesterol-lowering therapy in familial hypercholesterolemia (FH), particularly on side effects to changes in plasma coenzyme Q10 and proprotein convertase subtilisin/kexin type 9 levels. We enrolled 17 Japanese patients with heterozygous FH (12 men, 63.9 ± 7.4 years old) with single LDL receptor gene mutations in a prospective open randomized study. Permitted maximum doses of rosuvastatin (20 mg/day), ezetimibe (10 mg/day), and granulated colestimide (3.62 g/day) were introduced sequentially. Serum levels of LDL cholesterol decreased significantly by -66.4% (p <0.001) and 44% of participants achieved LDL cholesterol levels <100 mg/dl. There were no serious side effects or abnormal laboratory data that would have required the protocol to have been terminated except for 1 patient with myalgia. Coadministration of ezetimibe and granulated colestimide further lowered serum LDL cholesterol more than rosuvastatin alone without changing plasma coenzyme Q10 and proprotein convertase subtilisin/kexin type 9 levels. In conclusion, adequate introduction of this aggressive cholesterol-lowering regimen can improve the lipid profile of FH.

Impact of reduced left atrial functions on diagnosis of paroxysmal atrial fibrillation: Results from analysis of time-left atrial volume curve determined by two-dimensional speckle tracking

BACKGROUND Atrial fibrillation is commonly associated with impaired reservoir and booster functions of the left atrium (LA). Recent advances in two-dimensional speckle tracking technique (2DST) enabled automatic analysis of the time-LA volume curve representing these functions. Our objective was to evaluate LA function in patients with or without paroxysmal atrial fibrillation (PAF) using 2DST. METHODS We studied 111 patients (68 men, age 62 ± 16 years) with (n = 53) or without (n = 58) PAF. After constructing time-LA volume curves from the apical four and two chamber views (iE33, Philips with QLAB 6.0, Philips Medical Systems, Bothell, WA, USA), maximal LA volume (LAVmax), preatrial contraction LA volume (LAVpreA), and minimum LA volume (LAVmin) were obtained. Then, LA reservoir volume (ARV=LAVmax-LAVmin) and active emptying volume (AEV=LAVpreA-LAVmin) were calculated to determine ARV/LAVmax as reservoir function and AEV/LAVpreA as booster pump function. RESULTS PAF was associated with greater LAVmax than that in controls (80 ± 21 ml versus 65 ± 16 ml, p < 0.001) and with reduced reservoir and booster functions (ARV/LAVmax 46 ± 9% versus 52 ± 7%; AEV/LAVpreA 29 ± 10% versus 36 ± 6%, p < 0.001). Multivariate logistic analysis demonstrated that ARV/LAVmax and AEV/LAVpreA were closely associated with the existence of PAF. CONCLUSION These results demonstrate that the present 2DST enables determining LA reservoir and booster functions, providing insights into the diagnosis of PAF.

A novel method for determining functional LDL receptor activity in familial hypercholesterolemia: Application of the CD3/CD28 assay in lymphocytes

BACKGROUND The objective of this study was to develop a new and simple method for measuring low-density lipoprotein receptor (LDLR) activity using peripheral lymphocytes enabling us to clinically diagnose familial hypercholesterolemia (FH) and ascertain the involved mutations (such as K790X mutation), that might not be clearly detected in the conventional method. METHODS Our method comprised the following 2 features: first, we used anti-CD3/CD28 beads to stimulate T-lymphocytes to obtain a uniform fraction of lymphocytes and maximum up-regulation of LDLR. Second, we excluded the possibility of overestimation of lymphocyte signals bound only to its surface, by adding heparin to the cultured lymphocytes used for the LDLR assay. RESULTS Based on the genetic mutation, the FH subjects were divided into 2 groups, K790X, (n=20) and P664L, (n=5), and their LDLR activities was measured by this method, which was found to be 55.3+/-8.9% and 63.9+/-13.8%, respectively, of that of the control group (n=15). In comparison, the LDLR activity was 86.1+/-11.6% (K790X) and 73.3+/-6.3% (P664L) of that of the control group when measured by the conventional method, indicating that impairment of LDLR function in FH K790X subjects was much more clearly differentiated with our method than with the conventional method (paired t-test, p<0.0001). The levels of LDLR expression also showed similar tendencies, that is, 89.4+/-13.2% (K790X) and 76.9+/-17.4% (P664L) of that of the control group when measured by the conventional method, and 78.1+/-9.7% (K790X) and 70.3+/-26.5% (P664L) when measured by our new method. In addition, we confirmed that there was little influence of statin treatment on LDLR activity among the study subjects when our method was used. CONCLUSION These results demonstrate that our new method is applicable for measuring LDLR activity, even in subjects with an internally defective allele, and that T-lymphocytes of the FH K790X mutation possess characteristics of that allele.

Extreme Contrast of Postprandial Remnant-Like Particles Formed in Abetalipoproteinemia and Homozygous Familial Hypobetalipoproteinemia

BACKGROUND Familial hypobetalipoproteinemia (FHBL) and abetalipoproteinemia (ABL) are rare inherited forms of hypolipidemia. Their differential diagnosis is important for predicting of the prognosis and selecting appropriate therapy. MATERIALS AND METHODS Genetic analysis was performed in two patients with primary hypocholesterolemia born from consanguineous parents. The oral fat tolerance test (OFTT) was performed in one patient with FHBL (apoB-87.77) and one with ABL as well as in four normal control subjects. After overnight fasting, blood samples were drawn. Serum lipoprotein and remnant-like particle (RLP) fractions were determined by HPLC analysis. RESULTS Both patients with homozygous FHBL were asymptomatic probably because of preserved levels of fat-soluble vitamins, especially vitamin E. The patients with FHBL were homozygous because of novel apoB-83.52 and apoB-87.77 mutations, and although one of them (apoB-87.77) had fatty liver disease, microscopic findings suggesting nonalcoholic steatohepatitis were absent. Fasting apoB-48 and RLP-triglyceride levels in the patient with homozygous FHBL, which were similar to those in normal control subjects, increased after OFTT both in normal control subjects and the patient with FHBL but not in the patient with ABL, suggesting that the fat load administered was absorbed only in the patient with FHBL. CONCLUSION Although lipid levels in the patients with homozygous FHBL and ABL were comparable, fasting, postoral fat loading of apoB-48, as well as RLP-triglyceride levels, may help in the differential diagnosis of FHBL and ABL and provide a prompt diagnosis using genetic analysis in the future.

Perfect Correspondence of Mitral Valve Perforation Using Real-Time 3-Dimensional Transesophageal Echocardiography

![Figure][1] [![Graphic][3] ][3] Critical information about the exact anatomic characteristics of the mitral valve can be obtained using real-time 3-dimensional transesophageal echocardiography (RT3D TEE), which could be used in planning an appropriate intervention strategy. The

Cardiac papillary fibroelastoma originated from atrial side of mitral valve leaflet

A 50-year-old Japanese woman was referred for investigation of electrocardiogram abnormality without any chest complaint. She had no remarkable past history except for hypercholesterolemia. No heart murmur was heard. Chest X-ray showed no abnormal findings. Transthoracic echocardiography incidentally demonstrated a single, mobile, circular mass of 15 mm diameter. By transesophageal echocardiography, this mass was found to be attached to the left atrial side of posterior mitral valve leaflet near anterior commissure (Fig. 1). The mass had somewhat rough surface, and its echogenicity was isoechoic including some low-echoic components. Color Doppler showed poor vascularity inside the mass. There was no evidence that any part of the tumor touched left atrial surface including mitral annular tissue, suggesting low possibility for cardiac myxoma, which commonly occurs from atrial tissue surface. Coronary angiography revealed normal left and right coronary arteries without any feeding artery to the mass. Thus, cardiac papillary fibroelastoma was highly suspected preoperatively. In an operation, the pedunculated tumor was resected along with a margin of endocardium. Gross specimen of tumor resembled a sea anemone with frondlike appearance. Pathological examination demonstrated papillary lesion with avascular fibrous core which showed coexistence of collagen fiber and elastic fiber (Fig. 2). No atypical cells were found. These findings proved this tumor to be cardiac papillary fibroelastoma, which is sometimes found among cardiac tumors. Fibroelastoma is found in *0.03% on post mortem autopsy [1] and is the third most common type of primary cardiac tumor, after myxoma and lipoma [2]. Echocardiographic features of cardiac papillary fibroelastoma include the following findings: (1) tumor is round, oval or irregular in appearance, with well-demarcated borders and homogeneous texture; (2) most are small (99% were \20 mm in largest dimension); and (3) nearly half of them have small stalks, and those with stalks are mobile [3]. Approximately 90% of papillary fibroelastomas are attached to valves, with the aortic valve being the most common location of involvement, followed by the mitral valve [3]. When atrioventricular valve is involved, the tumor is most often on the atrial side of the valve, as found in our case. The differential diagnosis includes other tumors, thrombus, and vegetations. Myxoma is larger and more heterogeneous than papillary fibroelastoma. Thrombus shows central echolucency due to clot lysis, laminated appearance, and does not have a pedicle. Vegetations are irregularly shaped, discrete echogenic masses and often move independently of intrinsic structures. Although M. Mori M. Kawashiri T. Hayashi T. Konno K. Hayashi H. Ino M. Yamagishi (&) Division of Cardiovascular Medicine, Kanazawa University Graduate School of Medicine, 13-1 Takara-machi, Kanazawa, Ishikawa 920-8641, Japan e-mail: myamagi@med.kanazawa-u.ac.jp

Impact of the right parasternal view with supine positioning for echocardiographic visualization of acute type A aortic dissection.

A 77-year-old woman was referred to our hospital with sudden-onset severe chest pain. Contrast-enhanced computed tomography (CT) scanning showed an intimal flap extending from the ascending thoracic aorta to the origin of the celiac artery from the abdominal aorta, which represented acute type A aortic dissection (Fig. 1a). After CT scanning, the patient underwent transthoracic echocardiography in the supine position using a sector transducer. Transthoracic echocardiography in the left parasternal, apical, and subcostal views did not clearly demonstrate acute type A aortic dissection. When the transducer was positioned at the right parasternal short axis view with supine positioning (Fig. 1b, insertion), an intimal flap of the ascending aorta extending by more than 270 of the vessel’s circumference at the pulmonary artery level was clearly visualized (Fig. 1b). Thus, echocardiography in the right parasternal view generated CT-like images. The patient successfully underwent graft replacement for ascending aortic dissection. The postoperative course was satisfactory and uncomplicated.

Non-bacterial thrombotic endocarditis associated with Trousseau's syndrome.

A 72-year-old Japanese woman with recent multiple cerebral infarctions was referred to our clinic for cardiac evaluation. Brain magnetic resonance imaging showed multiple cerebral infarctions in the right hemisphere (Fig. 1a, b). Regular and continuous monitoring ECG showed normal sinus rhythm and there was no symptom or sign suggesting the occurrence of paroxysmal atrial fibrillation. Laboratory findings demonstrated a thrombocytopenia with platelets of 8.0 9 10/ll, and elevations of fibrin degradation product at 58.7 lg/ml and D-dimer at 20.0 lg/ml. A series of blood cultures was negative. Echocardiography revealed an abnormal mass with relatively low echo intensity attached to the anterior mitral leaflet, moving with heart beats (Fig. 1c, d) which suggested the presence of vegetation associated with or without infective endocarditis. Under these conditions, there was no mitral regurgitation. We temporarily suspected non-bacterial thrombotic endocarditis as the cause of multiple cerebral infarctions, although another possibility accompanying the abnormal mass directly attached to the mitral valve leaflet should be considered [1]. On her 7th hospital day, she complained of epigastralgia and had a gastrointestinal fiberscope examination which showed enlarged folds in the gastric corpus (Fig. 2). On histopathology of the biopsy specimens, poorly differentiated adenocarcinoma was diagnosed (Fig. 2, inset). On the basis of these findings, we diagnosed this case as Trousseau’s syndrome which exhibits a hypercoagulable state due to underlying cancers and can cause systemic thrombotic events [2]. Every type of cancer has been reported to be associated with Trousseau’s syndrome. Under these conditions, friable vegetations, often observed by echocardiography, are formed in cardiac valves, as also observed in the present case [3]. For the treatment, anticoagulation therapy is mainly considered for the possible occurrence of systemic embolism. Although anticoagulation therapy comprising heparin at 20000 U/day was started, the patient unfortunately died of the cerebral hemorrhage associated with recurrent cerebral infarctions. We suggest that the possible existence of Trousseau’s syndrome is considered when one finds vegetation-like images in echocardiography. K. Nakashima T. Haraki H. Hirase Department of Cardiology, Takaoka City Hospital, Takaoka, Japan