Hokuriku-plus familial hypercholesterolaemia registry study: rationale and study design.

INTRODUCTION: Familial hypercholesterolaemia (FH) is an autosomal-dominant inherited genetic disease. It carries an extremely high cardiovascular risk associated with significantly elevated low-density lipoprotein (LDL) cholesterol. The diagnostic rate of this disease in some European nations is quite high, due to the presence of multiple prospective registries. On the other hand, few data-and in particular multicentre data-exist regarding this issue among Japanese subjects. Therefore, this study intends to assemble a multicentre registry that aims to comprehensively assess cardiovascular risk among Japanese FH patients while taking into account their genetic backgrounds. METHODS AND ANALYSIS: The Hokuriku-plus FH registry is a prospective, observational, multicentre cohort study, enrolling consecutive FH patients who fulfil the clinical criteria of FH in Japan from 37 participating hospitals mostly in Hokuriku region of Japan from April 2020 to March 2024. A total of 1000 patients will be enrolled into the study, and we plan to follow-up participants over 5 years. We will collect clinical parameters, including lipids, physical findings, genetic backgrounds and clinical events covering atherosclerotic and other important events, such as malignancies. The primary endpoint of this study is new atherosclerotic cardiovascular disease (ASCVD) events. The secondary endpoints are as follows: LDL cholesterol, secondary ASCVD events and the occurrence of other diseases including hypertension, diabetes and malignancies. ETHICS AND DISSEMINATION: This study is being conducted in compliance with the Declaration of Helsinki, the Ethical Guidelines for Medical and Health Research Involving Human Subjects, and all other applicable laws and guidelines in Japan. This study protocol has been approved by the Institutional Review Board at Kanazawa University. We will disseminate the final results at international conferences and in a peer-reviewed journal. TRIAL REGISTRATION NUMBER: UMIN000038210.

High frequency of a retinoid X receptor gamma gene variant in familial combined hyperlipidemia that associates with atherogenic dyslipidemia.

OBJECTIVE: The genetic background of familial combined hyperlipidemia (FCHL) has not been fully clarified. Because several nuclear receptors play pivotal roles in lipid metabolism, we tested the hypothesis that genetic variants of nuclear receptors contribute to FCHL. METHODS AND RESULTS: We screened all the coding regions of the PPARalpha, PPARgamma2, PPARdelta, FXR, LXRalpha, and RXRgamma genes in 180 hyperlipidemic patients including 60 FCHL probands. Clinical characteristics of the identified variants were evaluated in other 175 patients suspected of coronary disease. We identified PPARalpha Asp140Asn and Gly395Glu, PPARgamma2 Pro12Ala, RXRgamma Gly14Ser, and FXR -1g->t variants. Only RXRgamma Ser14 was more frequent in FCHL (15%, P<0.05) than in other primary hyperlipidemia (4%) and in controls (5%). Among patients suspected of coronary disease, we identified 9 RXRgamma Ser14 carriers, who showed increased triglycerides (1.62+/-0.82 versus 1.91+/-0.42 [mean+/-SD] mmol/L, P<0.05), decreased HDL-cholesterol (1.32+/-0.41 versus 1.04+/-0.26, P<0.05), and decreased post-heparin plasma lipoprotein lipase protein levels (222+/-85 versus 149+/-38 ng/mL, P<0.01). In vitro, RXRgamma Ser14 showed significantly stronger repression of the lipoprotein lipase promoter than RXRgamma Gly14. CONCLUSION: These findings suggest that RXRgamma contributes to the genetic background of FCHL.

Limited effects of long-term enzyme replacement therapy on the cardiac conduction system in Fabry disease.

The long-term effects of enzyme replacement therapy (ERT) on cardiac function and the conduction system in Fabry disease are not clearly understood. We report a case of a 48-year-old man with non-classical Fabry disease treated with ERT for 11 years. He was diagnosed with Fabry disease at age 27 years based on the presence of decreased alpha-galactosidase A activity in the peripheral leukocytes and of the causal alpha-galactosidase A mutation (Val339Gln). Subsequently, peritoneal dialysis was initiated for renal failure at age 35 years. ERT was initiated at age 39 years to halt the progression of cardiac dysfunction. Electrical conduction disturbances progressed gradually to complete atrioventricular block with atrial standstill during 9 years of ERT despite the lack of progression of ventricular hypertrophy. Although he underwent permanent pacemaker implantation to prevent sudden cardiac death, the atrioventricular junctional rhythm remained, thereby lowering the ventricular pacing rate. Based on this case, we recognize that the effects of ERT are limited for inhibiting the progression of Fabry disease and especially for inhibiting arrhythmia and conduction disturbances. Early diagnosis of Fabry disease and early initiation of ERT might be the key to further improvements in this disease and its associated conditions. .

Acute necrotizing eosinophilic myocarditis complicated by complete atrioventricular block promptly responded to glucocorticoid therapy.

Acute myocarditis is frequently accompanied with conduction disturbances. Complete atrioventricular (AV) block may occur in acute myocarditis, but rarely in eosinophilic myocarditis. Acute necrotizing eosinophilic myocarditis, the most severe form of eosinophilic myocarditis, is generally fatal, and rarely complicated by complete AV block. We report a case of a 66-year-old woman with acute necrotizing eosinophilic myocarditis who presented with general malaise and nausea. She suddenly fell into cardiogenic shock because of complete AV block and worsened heart failure. Ultrasound cardiography revealed pericardial effusion, edematous myocardium, and reduced contractility of the left ventricle. The biopsied specimens showed marked interstitial infiltration with predominant eosinophils accompanied with myocardial necrosis. Oral administration of glucocorticoid in moderate dose promptly resolved the complete AV block, her clinical symptoms, and cardiac function. We recognized that acute necrotizing eosinophilic myocarditis can be complicated by complete AV block. Steroid therapy could be effective in the treatment of conduction disturbance as well as myocardial inflammation. .

Long-term course of lipoprotein lipase (LPL) deficiency due to homozygous LPL(Arita) in a patient with recurrent pancreatitis, retained glucose tolerance, and atherosclerosis.

CONTEXT: Lipoprotein lipase (LPL) deficiency is a rare autosomal recessive disorder caused by LPL gene mutation and is characterized by severe hyperchylomicronemia. Patients with LPL deficiency suffer from the frequent recurrence of acute pancreatitis, but the underlying mechanisms are not fully understood. CASE REPORT: A 22-yr-old male Japanese patient with severe hyperchylomicronemia was admitted to our hospital in 1973. He had no consanguinity and no family history of hyperlipidemia. He was genetically diagnosed as LPL deficiency (homozygous for LPL(Arita)) with no LPL mass or activity in postheparin plasma. He has experienced recurrent acute pancreatitis 22 times during our 31-yr clinical follow-up, but no pancreatic pseudocyst, irregularity of the pancreatic duct, or abnormal pancreatic calcification was observed in computed tomography. Moreover, his pancreatic endocrine function, as assessed by the oral glucose tolerance test, has preserved more than 30 yr. Although he was a current smoker, no clinically significant atherosclerotic lesion had been observed. CONCLUSIONS: From the long-term observation of this patient, we propose that LPL deficiency is not invariably associated with high mortality and that even with repeated episodes of acute pancreatitis, pancreatic function may be slow to decline.

Abrupt progression of ventricular septal perforation after primary angioplasty for acute myocardial infarction.

A 61-year-old-man was transferred to our hospital because of progressive heart failure after reperfusion for acute myocardial infarction (MI). When he visited the local hospital with severe chest pain associated with inferior MI, transthoracic echocardiography revealed small ventricular septal perforation (VSP). The patient had emergent coronary angiography, which revealed total occlusion of the mid-portion of the right coronary artery. Primary angioplasty was successful for reperfusion. However, because of hemodynamic instability the patient was transferred to our hospital. Under these conditions, transthoracic echocardiography which was undertaken 3 hours after primary angioplasty, demonstrated progressive enlargement of the VSP probably due to reperfusion injury. The rupture site, which was further enlarged at the time of operation, was repaired using the patch exclusion technique. The patient could discharge without complications. We suggest that primary angioplasty may potentially induce late reperfusion injury in patients with VSP complicating MI.

Infantile Cases of Sitosterolaemia with Novel Mutations in the ABCG5 Gene: Extreme Hypercholesterolaemia is Exacerbated by Breastfeeding.

Few data exists regarding the clinical impact of breastfeeding in infantile sitosterolaemic cases. We report four Japanese infantile cases of sitosterolaemia, an extremely rare inherited disease characterised by increased serum levels of plant sitosterol, presenting with severe hypercholesterolaemia and systemic xanthomas exacerbated by breastfeeding. In these four cases, genetic analyses were performed for low-density lipoprotein (LDL) receptor, proprotein convertase subtilisin/kexin type 9 (PCSK9), LDL receptor adaptor protein 1 and ATP-binding cassette (ABC) subfamily G member 5 and 8 (ABCG5 and ABCG8) genes. We assessed their clinical manifestations, including responsiveness to a variety of treatments, especially to weaning from breastfeeding and use of ezetimibe. Two pairs of mutations in the ABCG5 gene in each case, including two novel mutations (c.130C>T or p.Ser44Ala and c.1813_1817delCTTTT or p.Pro558GlufsX14) and two known mutations (c.1306G>A or p.Arg389His and c.1336C>T or p.Arg446X), were identified. Significant reductions in cholesterol levels were obtained by means of weaning from breastfeeding alone. Substantial reductions in sitosterol levels, without any apparent side effects, were observed with ezetimibe. In conclusion, we have identified infantile Japanese sitosterolaemic subjects with extreme hypercholesterolaemia exacerbated by breastfeeding. Their unique response to weaning from breastfeeding, as well as to use of ezetimibe, could provide insights into the metabolic basis of sterols in humans.

Altered metabolism of low-density lipoprotein and very-low-density lipoprotein remnant in autosomal recessive hypercholesterolemia: results from stable isotope kinetic study in vivo.

BACKGROUND: Autosomal recessive hypercholesterolemia (ARH) exhibits different responsiveness to statins compared with that in homozygous familial hypercholesterolemia (FH). However, few data exist regarding lipoprotein metabolism of ARH. Therefore, we aimed to clarify lipoprotein metabolism, especially the remnant lipoprotein fractions of ARH before and after statin therapy. METHODS AND RESULTS: We performed a lipoprotein kinetic study in an ARH patient and 7 normal control subjects, using stable isotope methodology (10 mg/kg of [(2)H(3)]-leucine). These studies were performed at baseline and after the 20 mg daily dose of atorvastatin. Tracer/tracee ratio of apolipoprotein B (apoB) was determined by gas chromatography/mass spectrometry and fractional catabolic rates (FCR) were determined by multicompartmental modeling, including remnant lipoprotein fractions. FCR of low-density lipoprotein (LDL) apoB of ARH was significantly lower than those of control subjects (0.109 versus 0.450±0.122 1/day). In contrast, the direct removal of very-low-density lipoprotein remnant was significantly greater in ARH than those in control subjects (47.5 versus 2±2%). Interestingly, FCR of LDL apoB in ARH dramatically increased to 0.464 1/day, accompanying reduction of LDL cholesterol levels from 8.63 to 4.22 mmol/L after treatment with atorvastatin of 20 mg/d for 3 months. CONCLUSIONS: These results demonstrate that ARH exhibits decreased LDL clearance associated with decreased FCR of LDL apoB and increased clearance for very-low-density lipoprotein remnant. We suggest that increased clearance of remnant lipoprotein fractions could contribute to the great responsiveness to statins, providing new insights into the lipoprotein metabolism of ARH and the novel pharmacological target for LDLRAP1.

Comparison of effects of bezafibrate and fenofibrate on circulating proprotein convertase subtilisin/kexin type 9 and adipocytokine levels in dyslipidemic subjects with impaired glucose tolerance or type 2 diabetes mellitus: results from a crossover study.

BACKGROUND: Bezafibrate and fenofibrate show different binding properties against peroxisome proliferator-activated receptor subtypes, which could cause different clinical effects on circulating proprotein convertase subtilisin/kexin type 9 (PCSK9) levels and on various metabolic markers. METHODS: An open, randomized, four-phased crossover study using 400 mg of bezafibrate or 200mg of fenofibrate was performed. Study subjects were 14 dyslipidemia with impaired glucose tolerance or type 2 diabetes mellitus (61 ± 16 years, body mass index (BMI) 26 ± 3 kg/m², total cholesterol (TC) 219 ± 53 mg/dL, triglyceride (TG) 183 ± 83 mg/dL, high-density lipoprotein-cholesterol (HDL-C) 46 ± 8 mg/dL, fasting plasma glucose 133 ± 31 mg/dL and HbA1c 6.2 ± 0.8%). Subjects were given either bezafibrate or fenofibrate for 8 weeks, discontinued for 4 weeks and then switched to the other fibrate for 8 weeks. Circulating PCSK9 levels and other metabolic parameters, including adiponectin, leptin and urine 8-hydroxy-2'-deoxyguanosine (8-OHdG) were measured at 0, 8, 12 and 20 weeks. RESULTS: Plasma PCSK9 concentrations were significantly increased (+39.7% for bezafibrate and +66.8% for fenofibrate, p<0.001) in all patients except for one subject when treated with bezafibrate. Both bezafibrate and fenofibrate caused reductions in TG (-38.3%, p<0.001 vs. -32.9%, p<0.01) and increases in HDL-C (+18.0%, p<0.001 vs. +11.7%, p<0.001). Fenofibrate significantly reduced serum cholesterol levels (TC, -11.2%, p<0.01; non-HDL-C, -17.3%, p<0.01; apolipoprotein B, -15.1%, p<0.01), whereas bezafibrate significantly improved glucose tolerance (insulin, -17.0%, p<0.05) and metabolic markers (γ-GTP, -38.9%, p<0.01; adiponectin, +15.4%, p<0.05; urine 8-OHdG/Cre, -9.5%, p<0.05). CONCLUSION: Both bezafibrate and fenofibrate increased plasma PCSK9 concentrations. The addition of a PCSK9 inhibitor to each fibrate therapy may achieve beneficial cholesterol lowering along with desirable effects of respective fibrates.

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.

Marked aortic valve stenosis progression after receiving long-term aggressive cholesterol-lowering therapy using low-density lipoprotein apheresis in a patient with familial hypercholesterolemia.

In 1982, a 49-year-old Japanese woman had been referred to our hospital for further investigation of her hypercholesterolemia. She was diagnosed as heterozygous familial hypercholesterolemia, because of Achilles tendon xanthoma and a family history of primary hypercholesterolemia. Three years later, she had chest pain on effort and angina pectoris was diagnosed by coronary angiography. At that time, she underwent coronary artery bypass grafting surgery with 2 saphenous vein grafts (SVG). Because more aggressive cholesterol-lowering therapy was needed for secondary prevention of coronary artery disease (CAD), weekly low-density lipoprotein (LDL) apheresis was started postoperatively, combined with drug therapy. Since 1986, her serum total cholesterol levels before and after LDL apheresis remained approximately 200 mg/dl and 90 mg/dl, respectively. Although her coronary sclerosis, including the SVG, did not progress appreciably for a period of 20 years, stenotic changes of the aortic valve developed rapidly at age 70, leading to aortic valve replacement surgery in 2005 at age 72. These findings suggest that careful attention to the progression of aortic valve stenosis is needed for extreme hypercholesterolemic patients even under optimal cholesterol-lowering therapy for the secondary prevention of CAD.

Impact of severe earthquake on the occurrence of acute coronary syndrome and stroke in a rural area of Japan.

BACKGROUND: Although acute coronary syndrome (ACS) and stroke are known to increase after earthquake, few data exist regarding the effect of earthquake on these cardiovascular events in rural areas. METHODS AND RESULTS: The Noto Peninsula earthquake with a magnitude of 6.9 occurred at 9:45 a.m. on 25 March 2007. The first case of ACS occurred approximately 15 min later, whereas cerebral hemorrhage (CH) occurred 72 h after the onset of earthquake. During the 35 days after earthquake, among 49 patients who were attended by local ambulance, 5 patients with ACS (10.2%) and 8 with CH (16.3%) were documented and 4 died. The total number of both ACS and CH cases was greater than the averages for the same period of the past 3 years in this area (2.0 vs 5 and 2.3 vs 8, P<0.01). Interestingly, the most cases of ACS had occurred within 7 days after earthquake and for CH not until 35 days later. CONCLUSIONS: Even in rural areas a severe earthquake results in increased incidence of ACS and CH, which can occur at different times after the event, although the effects of other environmental factors should be further investigated.

CETP (cholesteryl ester transfer protein) promoter -1337 C>T polymorphism protects against coronary atherosclerosis in Japanese patients with heterozygous familial hypercholesterolaemia.

CETP (cholesteryl ester transfer protein) and HL (hepatic lipase) play a role in the metabolism of plasma lipoproteins, but the effects of CETP and LIPC (gene encoding HL) genotypes on coronary atherosclerosis may be dependent on LDL (low-density lipoprotein)-receptor activity. Recently, the -1337 C>T polymorphism in the CETP gene has been reported in REGRESS (Regression Growth Evaluation Statin Study) to be a major determinant of promoter activity and plasma CETP concentration. In the present study, we have investigated the effects of the CETP promoter -1337 C>T and LIPC promoter -514 C>T polymorphisms on serum lipid profiles and risk of coronary atherosclerosis in 206 patients (154 males) with heterozygous FH (familial hypercholesterolaemia). To evaluate coronary atherosclerosis, we used CSI (coronary stenosis index) calculated from coronary angiograms. The CETP -1337 T allele was less frequent in subjects with a CSI > or =14 (mean value) in the group with coronary artery disease (P=0.04, as determined by chi(2) test). ANOVA revealed that HDL-C (high-density lipoprotein-cholesterol) and triacylglycerol (triglyceride) levels were not significantly higher in the presence of the CETP promoter -1337 T allele. Combined with LIPC promoter polymorphisms, HDL-C levels were highest and CSI were lowest with CETP -1337 CT+TT and LIPC -514 CC genotypes, but a significant interaction was not shown. A multiple logistic regression analysis revealed that, in patients with coronary atherosclerosis, the CETP- 1337 CC genotype was a significant genetic risk factor in FH (odds ratio=2.022; P=0.0256). These results indicate that the CETP promoter -1337C>T polymorphism is associated with the progression of coronary atherosclerosis in Japanese patients with FH, independent of HDL-C and triacylglycerol levels.

Type III hyperlipoproteinemia exaggerated by Sheehan's syndrome with advanced systemic atherosclerosis: a 28-year clinical course.

A 38-year-old Japanese woman was admitted to hospital for further examination of systemic xanthomas. She had a past history of genital bleeding during her third delivery at the age of 21 years. She was diagnosed with Sheehan's syndrome. Her serum total cholesterol and triglyceride concentrations were 500 and 898 mg/dl, respectively. She was also diagnosed as having type III hyperlipoproteinemia on the basis of the presence of a broad-beta-band on agarose gel electrophoresis and extremely high concentrations of very-low-density lipoprotein cholesterol (310 mg/dl). The diagnosis was later confirmed by her apolipoprotein E isoforms (E2/E2) and genotypes (epsilon2/epsilon2). Thyroid and corticosteroid hormone replacement therapy cured the xanthomas, but also elevated her blood pressure. The serum concentration of intermediate-density lipoprotein cholesterol was consistently high, whereas that of low-density lipoprotein cholesterol was relatively low during the follow-up. Coronary atherosclerosis had already developed by the age of 38 years, and progressed significantly over the following 28 years. Severe stenotic lesions were observed in the bilateral renal arteries and carotid arteries, and in the abdominal aorta when she was 66 years old. These findings suggest that the continuous elevation of intermediate-density lipoprotein cholesterol for a long period contributed to the development of the atherosclerotic lesions.

ATP-binding cassette transporter G8 M429V polymorphism as a novel genetic marker of higher cholesterol absorption in hypercholesterolaemic Japanese subjects.

The ratio of serum plant sterols to cholesterol is positively correlated with the fractional cholesterol absorption, whereas serum precursors of cholesterol synthesis are positively correlated with cholesterol synthesis. Recently, two ABC (ATP-binding cassette) transporters, ABCG5 and ABCG8, have been described as playing an important role in the absorption and excretion of sterols. In the present study, we tested the hypothesis that genetic variation in ABCG5/ABCG8 influences the levels of serum plant sterol (sitosterol) and cholesterol precursor (lathosterol) in Japanese primary hypercholesterolaemic patients (n = 100). We identified a novel mutation [859T/C (C287R)] and a novel polymorphism [1285A/G (M429V)] at the ABCG5/ABCG8 loci, as well as four polymorphisms reported previously [1810C/G (Q604E), 161G/A (C54Y), 1199C/A (T400K) and 1895C/T (A632V)]. In carriers of the novel M429V variant, the serum level of sitosterol and the sitosterol/cholesterol ratio were significantly higher than those in non-carriers (3.64 compared with 2.56 microg/ml, and 1.45 microg/mg compared with 1.00 microg/mg respectively; P < 0.01 for both), and serum lathosterol tended to be lower (1.95 microg/ml compared with 3.03 microg/ml; P = 0.08), whereas no significant difference was observed in other lipid profiles. These four polymorphisms (1810C/G, 161G/A, 1199C/A and 1285A/G) generated six haplotypes, and the C/G/C/G haplotype was significantly associated with a higher sitosterol level and sitosterol/cholesterol ratio compared with the other five haplotypes (P < 0.05 for both). We conclude that, in 8% of patients with hypercholesterolaemia, the novel ABCG8 M429V variant was associated with higher cholesterol absorption efficiency. Future studies should investigate whether these findings have implications for the optimal cholesterol-lowering drug treatment in hypercholesterolaemic patients.