Published papers

Background: Several studies have reported that insulin resistance was a major risk factor for the onset of type 2 diabetes mellitus in individuals without diabetes or obesity. We aimed to clarify the association between insulin resistance and glycemic control in Japanese subjects without diabetes or obesity. Methods: We conducted a community-based cross-sectional study including 1083 healthy subjects (323 men and 760 women) in an urban area. We performed multivariate regression analyses to estimate the association between the homeostasis model assessment of insulin resistance (HOMA-IR) values and markers of glycemic control, including glycated haemoglobin (HbA1c), 1,5-anhydroglucitol (1,5-AG), and fasting plasma glucose (FPG) levels, after adjustment for potential confounders. Results: Compared with the lowest tertile of HOMA-IR values, the highest tertile was significantly associated with HbA1c and FPG levels after adjustment for potential confounders, both in men (HbA1c: β = 1.83, P = 0.001; FPG: β = 0.49, P < 0.001) and women (HbA1c: β = 0.82, P = 0.008; FPG: β = 0.39, P < 0.001). The highest tertile of HOMA-IR values was inversely associated with 1,5-AG levels compared with the lowest tertile (β = -18.42, P = 0.009) only in men. Conclusions: HOMA-IR values were associated with markers of glycemic control in Japanese subjects without diabetes or obesity. Insulin resistance may influence glycemic control even in a lean, non-diabetic Asian population.

Aims: The population-attributable fraction (PAF) is an indicator of the disease burden. In Western countries, the PAF of hypercholesterolemia in cardiovascular disease (CVD) is the highest among that for traditional risk factors; however, data for Asian populations are limited. Methods: A 24-year cohort study was conducted among 9,209 randomly selected participants who were not taking statins. We estimated the hazard ratio (HR) after adjusting for covariates and PAF associated with the serum total cholesterol (TC) levels in relation to CVD mortality. Results: The TC level was found to be positively associated with an increased risk of CVD, coronary heart disease (CHD) and cardiac death (CHD plus heart failure), with an HR of 1.08 (95% confidence interval [CI]: 1.00-1.16), 1.33 (95% CI: 1.14-1.55) and 1.21 (95% CI: 1.08-1.35) for a 1-SD increment in the serum TC level, respectively. Similar positive associations between the TC level and both CHD and cardiac death were observed after classifying the patients by age and sex. Furthermore, the highest serum TC level (≥6.72 mmol/L) was positively associated with CVD death, with an HR of 1.76 (95% CI: 1.25-2.47), as well as both CHD death and cardiac death. In contrast, no significant relationships were observed between the serum TC level and stroke. Meanwhile, the PAF for CVD, CHD, and cardiac deaths due to hypercholesterolemia (serum TC level ≥5.69 mmol/L, defined by the Japan Atherosclerosis Society) was 1.7%, 10.6% and 5.6%, respectively. Conclusions: The estimated PAF of CVD death due to hypercholesterolemia is moderately high, but lower than that for other risk factors, such as hypertension.

Aims: Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 ligands containing apolipoprotein B (LAB) and lectin-like oxidized LDL receptor-1 (LOX-1) are known as LOX-1-related modified LDL indicators. These indicators play an important role in the early phase atherosclerosis, but the relationship between these indicators and subclinical atherosclerosis, as represented by the cardioankle vascular index (CAVI), has not been assessed. We herein investigated the association of LOX-1- related modified LDL indicators and the CAVI in healthy, Japanese urban community inhabitants who were considered to be at low risk for cardiovascular disease (CVD). Methods: The participants were 515 healthy Japanese (310 men and 205 women) without a history of CVD, cancer or the use of medication for hypertension, diabetes or dyslipidaemia. To estimate the association between LOX-1-related modified LDL indicators (LAB, soluble form of LOX-1 (sLOX- 1)) and the CAVI, we performed multivariable linear regression analyses with possible confounders such as the serum LDL cholesterol level. Results: The plasma LAB showed a positive association with the CAVI in men (standardized coefficient: 0.11, p= 0.04). This relationship was not observed in women. On the other hand, no clear association was observed between the CAVI and the plasma sLOX-1 level in either sex. Conclusions: The plasma LAB levels may represent a useful marker for detecting potential atherosclerosis in healthy individuals considered to be at low risk for atherosclerosis and CVD. Further studies are needed to confirm the present findings.

Background: Although cryoablation (Cryo) has been advocated as an effective locoregional therapy for hepatocellular carcinoma (HCC), few studies have compared the outcomes with those of radiofrequency ablation (RFA) and microwave coagulation therapy (MCT). Methods: Consecutive patients with primary HCCs of <5 cm received Cryo or RFA/MCT between 1998 and 2011 and were monitored for local recurrence (defined as a recurrent tumor at or in direct contact with the ablated area) and overall complication rates. Results: The median tumor size was 2.5 cm in the Cryo group (n = 55) and 1.9 cm in the RFA/MCT group (n = 64; P < 0.001), but other patient characteristics were similar. Multivariate Cox regression analysis revealed Cryo as the only independent factor for improved 2-year local recurrence-free survival, with a hazard ratio (HR) of 0.3 (95 % confidence interval, 0.1–0.9; P = 0.02). Tumor diameter was a negative indicator of local recurrence-free survival (HR, 2.0; 95 % confidence interval, 1.1–3.5; P = 0.02). Subgroup analysis of patients with tumors of >2 cm demonstrated significantly better local recurrence rates in the Cryo group compared with the RFA/MCT group (21 vs. 56 % at 2 years; P = 0.006). Overall complication rates and incidences of Clavien–Dindo classification grade ≥III were identical (both P = 1.00). No in-hospital mortality occurred. Conclusions: Appropriate use of Cryo, as shown in this series, is safe and provides significantly improved local control for the treatment of primary HCCs of >2 cm compared with RFA/MCT.

Objective: Metabolomics is a promising approach to the identification of biomarkers in plasma. Here, we performed a population-based, cross-sectional study to identify potential biomarkers of alcohol intake and alcohol-induced liver injury by metabolomic profiling using capillary electrophoresis-mass spectrometry (CE-MS). Methods: Fasting plasma samples were collected from 896 Japanese men who participated in the baseline survey of the Tsuruoka Metabolomics Cohort Study, and 115 polar metabolites were identified and absolutely quantified by CE-MS. Information on daily ethanol intake was collected through a standardized, self-administered questionnaire. The associations between ethanol intake and plasma concentration of metabolites were examined. Relationships between metabolite concentrations or their ratios and serum liver enzyme levels in the highest ethanol intake group (>46.0 g/day) were then examined by linear regression analysis. Replication analysis was conducted in 193 samples collected from independent population of this cohort. Results: Nineteen metabolites were identified to have an association with daily alcohol consumption both in the original and replication population. Three of these metabolites (threonine, glutamine, and guanidinosuccinate) were found to associate well with elevated levels of serum liver enzymes in the highest ethanol intake group, but not in the non-drinker group. We also found that the glutamate/glutamine ratio had a much stronger relation to serum γ-glutamyltransferase, aspartate transaminase, and alanine transaminase than glutamate or glutamine alone (standardized beta = 0.678, 0.558, 0.498, respectively). Conclusions: We found 19 metabolites associated with alcohol intake, and three biomarker candidates (threonine, guanidinosuccinate and glutamine) of alcohol-induced liver injury. Glutamate/glutamine ratio might also be good biomarker.

Background/Objectives: Serum polyunsaturated fatty acid (PUFA) composition reflects dietary intake and is related to risks for cardiovascular diseases. We hypothesized that serum n-3 PUFA composition, especially including long-chain n-3 PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), is associated with inflammatory status, which is related to increased risk for cardiovascular diseases. Subjects/Methods: We investigated the relationship between serum PUFA composition and high-sensitivity C-reactive protein (hs-CRP) levels in a cross-sectional study among 1,102 healthy men and women aged 40–74 years who reside in Kobe City. Multiple linear regression models that predict hs-CRP level were prepared to confirm the contribution of serum total n-3 PUFA, long-chain n-3 PUFA, EPA and DHA compositions after adjusting for other PUFAs and atherosclerotic risk factors. Results: The serum n-3 PUFA, particularly long-chain n-3 PUFA, compositions were inversely associated with the hs-CRP levels. The standardized regression coefficient was −0.089 (p < 0.01) for total n-3 PUFA, −0.091 (p < 0.01) for long-chain n-3 PUFA, −0.071 (p = 0.03) for EPA, and −0.068 (p = 0.04) for DHA. The n-6 PUFA compositions were also inversely associated with the hs-CRP levels (−0.169 [p < 0.01] for total n-6 PUFA and −0.159 [p < 0.01] for linoleic acid). Conclusions: The serum n-3 PUFA compositions were inversely related with the hs-CRP levels, similar associations were also observed in n-6 PUFA compositions. Our results suggest that dietary PUFA intake was inversely associated with attenuated inflammation in healthy Japanese population.

Objectives This study sought to investigate the effect of daily glucose fluctuation on coronary plaque properties in patients with coronary artery disease (CAD) pre-treated with lipid-lowering therapy. Background There is growing evidence that glucose fluctuation, as a residual risk apart from dyslipidemia, is an important factor contributing to the development of CAD. Methods This prospective study enrolled 70 consecutive CAD patients who were referred for percutaneous coronary intervention and whose low-density lipoprotein cholesterol level was

BACKGROUND AND PURPOSE - : Educating the youth about stroke is a promising approach for spreading stroke knowledge. The aim of this study was to verify communication of stroke knowledge to parents by educating junior high school students about stroke. METHODS - : We enrolled 1127 junior high school students (age, 13-15 years) and their parents in the Tochigi prefecture, Japan. All students received a stroke lesson, watched an animated cartoon, and read the related Manga comic as educational aids. The students took back home the Manga and discussed what they learned with their parents. Questionnaires on stroke knowledge were given to all at baseline and immediately after the lesson. RESULTS - : A total of 1125 students and 915 parents answered the questionnaires. In the students, the frequency of correct answers increased significantly for all questions on stroke symptoms except for headache, and for all questions on risk factors after the lesson. In the parents, the correct answer rates increased for stroke symptoms except for headache and numbness in one side of the body, and for all questions on risk factors except for hypertension. Ninety-one percent of students and 92.7% of parents correctly understood the Face, Arm, Speech, and Time (FAST) mnemonic after the lesson. CONCLUSIONS - : Improvement of stroke knowledge immediately after the stroke lesson was observed in parents as well as their children, which indicated that our teaching materials using the Manga was effective in delivering the stroke knowledge to parents through their children.

Tyrosine kinase 2 (TYK2) is a type I interferon (IFN) signaling pathway gene and was previously reported to be a risk factor for systemic lupus erythematosus (SLE) in Caucasian populations. In order to test for its genetic association with SLE in a Japanese population, TYK2 single nucleotide polymorphisms (SNPs), rs2304256, rs12720270 and rs280519, were genotyped. A case - control association study was performed in a total of 411 Japanese SLE patients and 467 healthy controls. Linkage disequilibrium (LD) among TYK2 SNPs was examined. According to the data from 94 healthy controls, non-synonymous rs2304256 resulting in Val → Phe substitution was revealed to be in a LD with rs12720270 and rs280519. Therefore, we further genotyped rs2304256 as a tag SNP in the full sample sets. As a result, no differences in genotype distribution and allelic frequencies of rs2304256 were found between SLE patients and healthy controls. In conclusion, TYK2 is not a genetic risk factor for SLE in a Japanese population. Our result suggests that there is an ethnic difference in the susceptibility genes for SLE.

Background: Although endothelium-dependent vasodilatation has been used as a marker of endothelial dysfunction (ED), there have been no reliable plasma markers for ED. Oxidative stress, which is a major determinant of ED, oxidizes tetrahydrobiopterin (BH4), an essential cofactor of endothelial type nitric oxide synthase (eNOS), and resulted in the relative deficiency of BH4. Methods and Results: In 163 patients with cardiovascular disorders, the plasma levels of BH4 and 7, 8-dihydrobiopterin (BH2) by high performance liquid chromatography were measured and compared with the flow-mediated (FMD) vasodilatory response of the brachial artery, which was measured by ultrasonography. The effects of atorvastatin on plasma pteridine levels and FMD were examined in patients with multiple coronary risk factors. There was a positive relationship between FMD and plasma BH4 levels and a negative relationship between FMD and plasma BH2 levels. Subsequently, a strong positive relationship between FMD and the BH4/BH2 ratio (r=0.585, P<0.0001) was found. Although we did not find any significant relationship between pteridine levels and individual traditional risk factors, the BH4/BH2 ratio in patients with more than 2 risk factors showed significant reductions compared with that in those without risk factors. Statin treatment improved FMD in association with an increase in the plasma BH4/BH2 ratio. Conclusions: Plasma pteridine levels were associated with endothelial dysfunction in cardiovascular disorders.

Background: Estrogen is considered to be cardioprotective, but estrogen replacement therapy for postmenopausal women has not shown results for either primary or secondary cardiovascular event prevention. During normal pregnancy, women have significantly higher levels of estrogen and it may be endogenous estrogen that helps prevent atherosclerosis. Methods and Results: The present cross-sectional study examined the association between pregnancy followed by delivery and clinical atherosclerosis using the brachial-ankle pulse wave velocity (PWV). A total of 2,560 women undergoing annual health screening at the Institute of Hyogo Prefecture Health Promotion Association in Japan were recruited. Pregnancy history (the age of menarche/menopause and the number of gravida/para), conventional coronary risk factors, and brachial-ankle PWV were recorded. Multivariate linear regression by stepwise selection analysis demonstrated that women who had 1 or more deliveries had a significantly lower PWV, independent of age and other conventional coronary risk factors. Conclusions: Pregnancy followed by delivery may decrease arterial stiffness and prevent the progress of atherosclerosis in women. The contribution of such a pregnancy followed by delivery-related decrease in arterial stiffness to the reduction of cardiovascular disease in women should be further evaluated.

Elevation of serum remnant lipoprotein concentration is an emerging risk factor for coronary artery disease. An immunoseparation procedure for remnant-like particle cholesterol(RLP-C) has been evaluated extensively in recent years. In addition, a new detergent-based method has been developed and applied to automated analyzer as "MetaboLead RemL-C" (RemL-C, KYOWA MEDEX CO., LTD.). Then, we compared the concentrations of remnant lipoproteins as RemL-C with those as RLP-C in various conditions. RemL-C assay was intra-assay-reproducible (n=20, CVs: 0.6-2.2%), and reproducible for 2 days in the refrigeration and for 8 hours in room temperature. This assay was also inter-assay-reproducible (during 5 days in the deep freezing, CVs: 1.6-3.0%). The available range for RemL-C assay was between 0.09 and 121.1 mg/dl. There were no detectable interferences from hemoglobin, free/conjugated bilirubin, chyle, and Intrafat. However, heparin influenced the titer of RemL-C concentrations. Correlation of values between RLP-C and RemL-C in 123 samples was excellent (r=0.924, p<0.001). However, different responses to intermediate lipoprotein fraction derived from a patients with type III hyperlipidemia were observed. In conclusion, RemL-C and RLP-C measurements may have a similar clinical significance. Differences in sensitivity for intermediate lipoprotein fraction between both methods may exist.

Estimation of Glomerular filtration rate (GFR) is crucial for the detection of renal insufficiency. In clinical practice, GFR is generally estimated from Ccr by some prediction formulas including the serum creatinine concentration and some variables: age, sex, body size. It has been suggested that serum cystatin C is less influenced by sex, body size, muscular mass or inflammation. In several studies, serum cystatin C performed better than serum creatinine did as a marker to detect GFR reduction. We developed the formula for predicting creatinine clearance (Ccr) from serum cystatin C, serum creatinine and serum beta 2-microgroburin by multiple regression analysis. In this study, we analysed 24-hour Ccr and variables (sex, age and BMI) in 82 subjects with renal diseases to develop suitable formulas. Our serum cystatin C formula is as follows: Ccr (ml/min/1.73m2) = (12.14-0.03 x age-1.72 x serum cystatin C) 2. Correlation between measured 24-hour Ccr and predicted Ccr by our serum cystatin C formula was higher (r=0.852) than our serum creatinine formula (r=0.755), serum beta 2-microgroburin formula (r=0.793), Cockcroft-Gault formula (r=0.836) and Horio formula (r=0.825). Accuracy within 15% was higher (39.0%) than other formulas (25.6-30.5%). Our formula using serum cystatin C for predicting Ccr is a useful and precise marker for Ccr than other commonly used formulas using serum creatinine.

The authors studied whether skin perfusion pressure (SPP) measurements can be used to accurately predict wound healing in critical limb ischemia (CLI) and to select peripheral arterial reconstructive procedures. Methods. Forty-seven patients (33 men and 14 women, age 36ĝ€"83 years) with 69 ischemic limbs with foot ulcers or gangrene were studied retrospectively. Skin perfusion pressure was compared to the treatment outcomes (ulcers healed and ulcers that failed to heal). As a diagnostic test for CLI, the sensitivity, specificity, and the positive and the negative predictive values (PPV, NPV) of SPP measurement were calculated; the data was then analyzed by the receiver operation characteristic (ROC) curve. Results. According to the ROC curve, the best SPP measurement performance was at 35 mmHg. Conclusion. Wound healing at the appropriate amputation level must be predicted to minimize invasive debridement. Skin perfusion pressure measurement is useful for predicting wound healing in the presence of CLI. Skin perfusion pressure ĝ‰¥ 35 mmHg is requisite for wound healing; at SPP

The aim of this study was to investigate the types and prevalence of disease-specific antinuclear antibodies (ANAs) and their relationship to rheumatic diseases in the general Japanese population. An immunofluorescence (IF) method was used for the first screening of ANA levels in serum samples obtained from 2181 residents of a small Japanese town. Individuals positive for IF-ANA were then further tested for disease-specific ANAs using eight enzyme immunoassays. Physical status and the presence of illness were determined by means of questionnaires and medical examinations. Based on the result of the IF-ANA assay, the rates of positive samples at 1:40 and 1:160 dilutions were 26.0 and 9.5%, respectively, with females have significantly higher positivity rates than males (P < 0.0001). Among 566 IF-ANA-positive individuals, 100 individuals were found to have 114 disease-specific ANAs. Anti-SSA/ Ro, anti-centromere, and anti-U1RNP antibodies were detected in 58, 30, and 11 individuals, respectively, but anti-Sm, anti-Scl-70, and anti-Jo-1 antibodies were undetectable. Questionnaires and medical examinations revealed that among 60 disease-specific ANA-positive individuals that were available for testing, six had Sjögren's syndrome (SS), five were suspected of having SS, and five had rheumatoid arthritis. Surprisingly, 34 (57%) of the disease-specific ANA-positive individuals were clinically healthy. Anti-SSA/Ro, anti-centromere, and anti-U1RNP antibodies were quite frequent among clinically healthy Japanese subjects, although anti-Sm, anti-Scl-70, and anti-Jo-1 antibodies were not. Of the 60 individuals who tested positive for disease-specific ANAs, 30% (18/60) actually manifested systemic rheumatic diseases, while 50% showed no detectable signs or symptoms of rheumatic diseases.

Objective. To examine whether serum procalcitonin (PCT) concentrations are useful for distinguishing bacterial infections from disease flares in patients with systemic autoimmune diseases. Methods. Patients with systemic autoimmune diseases who were admitted to our hospitals due to either a suspected deterioration of their primary diseases or an infectious disease were enrolled. Serum PCT levels were measured in 99 serum samples of 98 patients who had elevated serum C-reactive protein (CRP) levels; 29 samples were obtained from patients with bacterial infections, and 70 samples were obtained from patients with disease deterioration without a detectable infection. The diagnostic accuracy, sensitivity, and specificity for identifying a bacterial infection were estimated using the receiver-operating characteristic curve. Multiple logistic regression analysis was also done with PCT level, age, sex, steroid dose, and use of immunosuppressive agents. Results. Serum PCT levels were higher in the bacterial infection group than in the disease flare group (mean ± SD, 4.539 ± 9.677 vs 0.116 ± 0.127; p < 0.0001). The diagnostic accuracy of PCT for bacterial infection was 0.797, sensitivity 53.3%, and specificity 97.1%. On multivariate analysis, the odds ratio of a PCT ≥ 0.5 ng/ml was significant (OR 59.085, 95% CI 7.705-453.088, p < 0.0001) for identifying bacterial infection. Conclusion. Elevated serum PCT levels have a good specificity for diagnosing bacterial infection in patients with systemic autoimmune diseases regardless of their dosage of oral corticosteroids and immunosuppressive agents.

Objective. To demonstrate the existence of oxidative stress and the role of the antioxidant thioredoxin (TRX) in Sjögren's syndrome (SS). Methods. Labial biopsy specimens from patients with SS were analyzed immunohistochemically to detect 8-hydroxy-2′-deoxyguanosine (8-OHdG), 4-hydroxy-2-nonenal (4-HNE), nitrotyrosine, and TRX. Levels of TRX in saliva and plasma were quantified by ELISA. To analyze the effect of TRX on human salivary gland (HSG) cells, recombinant TRX (rTRX)-treated HSG cells were stimulated by interferon-γ (IFN-γ) for detecting interleukin 6 (IL-6) with ELISA and RT-PCR, or stimulated with IFN-γ and anti-Fas antibody for analyzing Fas-induced apoptosis with PI/annexin V staining. Results. Large amounts of 8-OHdG, 4-HNE, nitrotyrosine, and TRX were produced in salivary duct cells of SS patients, whether there was periductal lymphocytic infiltration or not. Strong TRX expression was detected in acinar cells from 13 of 19 SS specimens. Levels of salivary TRX were significantly higher in SS patients than in controls (p < 0.05), and were inversely related to the salivary flow rates in SS patients. Patients who showed acinar TRX expression had higher salivary TRX levels than those who did not (p < 0.05). Interferon-γ-induced expression of IL-6 and Fas-mediated apoptosis in HSG cells were significantly suppressed by pretreating cells with rTRX. Conclusion. Parallel production of oxidative stress markers together with massive secretion of TRX suggests that oxidative stress induces TRX in the salivary gland. Moreover, suppression of IL-6 production and apoptosis by rTRX in HSG cells suggests TRX acts to protect the salivary glands of SS patients from tissue damage.

Background: Rheumatoid factor (RF) and autoantibodies against cyclic citrullinated peptide (CCP) are markers that might help physicians diagnose rheumatoid arthritis. Purpose: To determine whether anti-CCP antibody more accurately identifies patients with rheumatoid arthritis and better predicts radiographic progression than does RF. Data Sources: MEDLINE through September 2006 and reference lists of retrieved studies and review articles. Study Selection: Studies in any language that enrolled at least 10 participants and that examined the role of anti-CCP antibody and RF in the diagnosis or prognosis of known or suspected rheumatoid arthritis. Data Extraction: Two authors independently evaluated studies for inclusion, rated methodological quality, and abstracted relevant data. Data Synthesis: The DerSimonian-Laird random-effects method was used to summarize sensitivities, specificities, and positive and negative likelihood ratios from 37 studies of anti-CCP antibody and 50 studies of RF. The pooled sensitivity, specificity, and positive and negative likelihood ratios for anti-CCP antibody were 67% (95% CI, 62% to 72%), 95% (CI, 94% to 97%), 12.46 (CI, 9.72 to 15.98), and 0.36 (CI, 0.31 to 0.42), respectively. For IgM RF, the values were 69% (CI, 65% to 73%), 85% (CI, 82% to 88%), 4.86 (CI, 3.95 to 5.97), and 0.38 (CI, 0.33 to 0.44). Likelihood ratios among IgM RF, IgG RF, and IgA RF seemed to be similar. Results from studies of patients with early rheumatoid arthritis were similar to those from all studies. Three of 4 studies found that risk for radiographic progression was greater with anti-CCP antibody positivity than with IgM RF positivity. Limitations: Many studies had methodological limitations. Studies of RF were heterogeneous and had wide ranges of sensitivity and specificity. Conclusions: Anti-CCP antibodies are more specific than RF for diagnosing rheumatoid arthritis and may better predict erosive disease.