Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis: a prospective observational cohort study

Risk factors associated with the occurrence of hip fracture in Japanese patients with rheumatoid arthritis (RA) were evaluated in a prospective, observational cohort study. Physical disability, advanced age, history of total knee replacement (TKR), and low body mass index (BMI) appear to be associated with the occurrence of hip fracture.

INTRODUCTION

This study seeks to evaluate the association between potential risk factors and the occurrence of hip fractures in Japanese RA patients.

METHODS

A total of 9,720 patients (82.1% female; mean age, 55.7 years) with RA were enrolled in a prospective observational study from 2000 to 2010. Self-reported hip fractures were verified using patient medical records. Cox proportional hazards models were used to analyze independent contributions of various risk factors to hip fracture occurrence.

RESULTS

During a mean follow-up of 5.2 years, 152 patients reported 152 hip fractures. Among these patients, 97 hip fractures in 97 patients (15 males, 82 females) were verified with medical records. Japanese version of the Health Assessment Questionnaire (J-HAQ) disability score [per 1 score, hazard ratio (HR), 2.64; 95% confidence interval (CI), 1.94-3.58], age (per 10 years; HR, 1.53; 95% CI, 1.25-1.87), history of TKR (HR, 3.75; 95% CI, 1.57-8.96), and BMI (per 1 kg/m2, HR, 0.92; 95% CI, 0.86-0.99) were significantly associated with hip fractures. Among the scores on the eight domains of the J-HAQ, J-HAQ (arising) (HR, 1.74; 95% CI, 1.28-2.36) and J-HAQ (hygiene) (HR, 1.58; 95% CI, 1.11-2.24) were significantly correlated with the occurrence of hip fracture.

CONCLUSIONS

High J-HAQ disability score, advanced age, history of TKR, and low BMI appear to be associated with the occurrence of hip fractures in Japanese RA patients. Among the eight domains of the J-HAQ, arising and hygiene disabilities appear to be correlated with the occurrence of hip fractures in this patient population.

The use of a ceramic talar body prosthesis in patients with aseptic necrosis of the talus

The purpose of this study was to evaluate the clinical results of a newly designed prosthesis to replace the body of the talus in patients with aseptic necrosis. Between 1999 and 2006, 22 tali in 22 patients were replaced with a ceramic prosthesis. A total of eight patients were treated with the first-generation prosthesis, incorporating a peg to fix into the retained neck and head of the talus, and the remaining 14 were treated with the second-generation prosthesis, which does not have the peg. The clinical results were assessed by the American Orthopaedic Foot and Ankle Society ankle/hindfoot scale. The mean follow-up was 98 months (18 to 174). The clinical results of the first-generation prostheses were excellent in three patients, good in one, fair in three and poor in one. There were, however, radiological signs of loosening, prompting a change in design. The clinical results of the second-generation prostheses were excellent in three patients, good in five, fair in four and poor in two, with more favourable radiological appearances. Revision was required using a total talar implant in four patients, two in each group. Although the second-generation prosthesis produced better results, we cannot recommend the use of a talar body prosthesis. We now recommend the use of a total talar implant in these patients.

Circulating TNF receptor 2 is associated with the development of chronic kidney disease in non-obese Japanese patients with type 2 diabetes

AIMS

Chronic low-grade inflammation and/or obesity are suggested to induce chronic kidney disease (CKD) in patients with type 2 diabetes. This cross-sectional study was performed to investigate the relationship between inflammatory biomarkers and CKD in non-obese patients with type 2 diabetes.

METHODS

106 non-obese Japanese patients with type 2 diabetes were recruited for the measurement of GFR, TNF, HMW adiponectin, leptin, hsCRP and some variables including urinary albumin. BMI, serum creatinine, and urinary albumin levels were 22.2 ± 0.2 kg/m(2) (17.1-24.9 kg/m(2)), 0.76 ± 0.02 mg/dl (0.39-1.38 mg/dl), 40.4 ± 4.3mg/gCr (1.6-195.0mg/gCr), respectively. They were stratified into two groups based on the value of eGFR: low eGFR (eGFR<60 ml/min/1.73 m(2)) and normal eGFR (eGFR>60 ml/min/1.73 m(2)). Logistic regression analysis was used for statistical analysis.

RESULTS

Whereas univariate logistic regression analysis showed that gender, diabetes duration, triglyceride, HDL cholesterol, uric acid, urinary albumin, and soluble TNF receptors (sTNF-R1, sTNF-R2) are associated with the development of stage 3 CKD, multivariate logistic regression analysis revealed that sTNF-R2 (Odds ratio 1.003, 95% confidence interval 1.000 to 1.005, P=0.030) showed significant associations with the development of stage 3 CKD.

CONCLUSIONS

Circulating TNF receptor 2 is an independent risk factor for CKD in non-obese Japanese patients with type 2 diabetes.

Hypoxanthine guanine phosphoribosyltransferase (HPRT) mutations in the Asian population

Mutation of hypoxanthine guanine phosphoribosyltransferase (HPRT) gives rise to Lesch-Nyhan syndrome, which is characterized by hyperuricemia, severe motor disability, and self-injurious behavior, or HPRT-related gout (Kelley-Seegmiller syndrome). The marked heterogeneity of HPRT deficiency is well known, with more than 300 mutations at the HPRT gene locus having been reported (deletions, insertions, duplications, abnormal splicing, and point mutations at different sites of the coding region from exons 1 to 9). We have identified mutations in Asian families with patients manifesting different clinical phenotypes, including rare cases of female subjects, by analyzing all nine exons of the HPRT gene (HPRT1) from genomic DNA and reverse-transcribed mRNA using the polymerase chain reaction technique coupled with direct sequencing. We developed suitable methods to detect the mutations identified from respective families with HPRT deficiency. Then, prenatal genetic diagnoses in HPRT-deficient families were carried out using both mRNA and genomic DNA from chorionic villi or amniotic fluid cells. As shown here in the heterogeneity of HPRT mutations, the spectrum of 70 mutations identified in the Asian population fits the four main conclusions that emerged previously from worldwide analysis.

Molecular characterization of a deletion in the HPRT1 gene in a patient with Lesch-Nyhan syndrome

Lesch-Nyhan syndrome is caused by a deficiency of hypoxanthine phosphoribosyltransferase (HPRT) encoded by HPRT1. About 20% of patients have a deletion of HPRT1 and large deletions of HPRT1 are not always fully characterized at the molecular level. Here, we report on a case of Lesch-Nyhan syndrome with a 33-kb deletion involving exon 1 of HPRT1. This novel mutation is caused by a nonhomologous recombination between different classes of interspersed repetitive DNA.

Smoking and adipose tissue inflammation suppress leptin expression in Japanese obese males: potential mechanism of resistance to weight loss among Japanese obese smokers

BACKGROUND

The effect of smoking on leptin regulation is controversial. Smoking may induce low-grade inflammation. Recent series of studies indicated the critical role of macrophage migration in the establishment of adipose tissue inflammation. In this study, we aimed to see the effects of smoking and inflammation on leptin regulation both at cellular and epidemiological levels.

METHODS

We compared the concentration of inflammatory markers and serum leptin levels among Japanese male subjects. Additionally, leptin and intercellular adhesion molecule (ICAM) -1 gene expression was assessed in adipocytes co-cultured with or without macrophages in the presence or absence of nicotine and/or lipopolysaccharide (LPS).

RESULTS

In subjects with BMI below 25 kg/m2, both WBC counts and soluble-ICAM-1 levels are significantly higher in smokers than in non-smokers. However, leptin concentration did not differ according to smoking status. However, in subjects with BMI over 25 kg/m2, smokers exhibited significantly lower serum leptin level as well as higher WBC counts and s-ICAM-1 concentration as compared with non-smokers. Leptin gene expression was markedly suppressed in adipocytes co-cultured with macrophages than in adipocyte culture alone. Furthermore, nicotine further suppressed leptin gene expression. ICAM-1 gene expression was markedly up-regulated in adipocytes co-cultured with macrophages when stimulated with LPS.

CONCLUSIONS

Adipose tissue inflammation appears to down-regulate leptin expression in adipose tissues. Nicotine further suppresses leptin expression. Thus, both smoking and inflammation may diminish leptin effect in obese subjects. Therefore, obese, but not normal weight, smokers might be more resistant to weight loss than non-smokers.

Smoking, white blood cell counts, and TNF system activity in Japanese male subjects with normal glucose tolerance

BACKGROUND

Cigarette smokers have increased white blood cell (WBC) counts and the activation of tumor necrosis factor (TNF). The effect of smoking on WBC counts and TNF system activity, however, has not been separately investigated yet.

SUBJECTS AND METHODS

One hundred and forty-two Japanese male subjects with normal glucose tolerance were recruited. They were stratified into two groups based on the questionnaire for smoking: one with current smokers (n = 48) and the other with current non-smokers (n = 94). Whereas no significant differences were observed in age, BMI, high molecular weight (HMW) adiponectin, and TNF-α between the two groups, current smokers had significantly higher soluble TNF receptor 1 (sTNF-R1) (1203 ± 30 vs. 1116 ± 21 pg/ml, p = 0.010) and increased WBC counts (7165 ± 242 vs. 5590 ± 163/μl, p < 0.001) and lower HDL cholesterol (55 ± 2 vs. 60 ± 1 mg/dl, p = 0.031) as compared to current non-smokers. Next, we classified 48 current smokers into two subpopulations: one with heavy smoking (Brinkman index ≥ 600) and the other with light smoking (Brinkman index < 600).

RESULTS

Whereas no significant difference was observed in age, BMI, HMW adiponectin, WBC counts and TNF-α, sTNF-R1 and sTNF-R2 were significantly higher in heavy smoking group (1307 ± 44 vs. 1099 ± 30 pg/ml, p < 0.001; 2166 ± 86 vs. 827 ± 62 pg/ml, p = 0.005) than in light smoking group, whose sTNF-R1 and sTNF-R2 were similar to non-smokers (sTNF-R1: 1116 ± 15 pg/ml, p = 0.718, sTNF-R2; 1901 ± 32 pg/ml, p = 0.437). In contrast, WBC counts were significantly increased in heavy (7500 ± 324/μl, p < 0.001) or light (6829 ± 352/μl, p = 0.001) smoking group as compared to non-smokers (5590 ± 178/μl). There was no significant difference in WBC counts between heavy and light smoking group (p = 0.158).

CONCLUSION

We can hypothesize that light smoking is associated with an increase in WBC counts, while heavy smoking is responsible for TNF activation in Japanese male subjects with normal glucose tolerance.

Calculation of personal dose equivalent for positron-emitting radionuclides using Monte Carlo code EGS5

The conversion coefficients, H'(d,α)/Φ, for monoenergetic positrons and positron-emitting radionuclides were calculated by using the user code UCICRPM of the Monte Carlo code EGS5 to estimate the radiation dose for medical staff involved in positron emission tomography examinations. From these coefficients, the dose equivalent rates per unit activity at 0.07 and 10 mm depths in a soft tissue for a straight-line source of 2-deoxy-2-[(18)F]fluoro-d-glucose ((18)F-FDG) were calculated by using the developed user code UCF18DOSE. The dose equivalent rates per unit activity at 0.07 and 10 mm depths were measured by using a personal dosemeter (DOSE(3)) under the same conditions as those considered in the calculation. The calculated dose equivalent rates per unit activity at 0.07 and 10 mm depths were 0.116 and 0.0352 pSv min(-1) Bq(-1), respectively, at 20 cm from the (18)F-FDG injection tube.

Periodontal disease and hypertriglyceridemia in Japanese subjects: potential association with enhanced lipolysis

Although periodontal disease may be associated with increased risk for atherosclerosis, the mechanism by which the disease causes atherosclerosis is still unknown. The candidates contributing to atherosclerosis in periodontal disease include low-grade inflammation such as C-reactive protein (CRP) and insulin resistance. A previous study demonstrated that periodontal therapy leads to an improvement in CRP as well as insulin resistance, indicating the relationship between periodontal disease and low-grade inflammation or insulin resistance. On the other hand, we previously demonstrated that serum triglyceride (TG) per se is independently associated with CRP or insulin resistance in Japanese populations with a body mass index (BMI) of 21.5 to 27.0 (midrange BMI). To the best of our knowledge, however, the relationship between periodontal disease and serum TG is not fully clarified. The first aim of the present study is to investigate whether periodontal disease is associated with serum TG in Japanese subjects with midrange BMI. If so, another aim of the study is to determine which mechanism is responsible for the association between periodontal disease and serum TG in these subjects. We have performed a periodontal examination in the Ogaki metabolic syndrome medical examination. One hundred sixty-two participants from 40 to 74 years old (56 men and 106 women; mean age, 66.43 ± 6.25 years) were enrolled in the study. Besides medical examination, oral panoramic radiograph was taken for all participants. Average bone score was also calculated. Periodontal bone destruction increased according to the age of the participants (r = 0.227, P < .004, Spearman correlation coefficient). Periodontal bone destruction was also associated with serum TG levels (r = 0.299, P = .000). This association was more evident in subjects with midrange BMI (r = 0.332, P < .001). In subjects with midrange BMI, TG was not correlated with BMI or waste circumstances. Furthermore, TG was not associated with age itself in the midrange BMI group. We then investigated the lipolytic activity of endotoxin in cocultures of adipocytes and macrophages. Low-dose lipopolysaccharide dose-dependently increased lipolytic activity in cocultures, and this activity was neutralized by anti-tumor necrosis factor α neutralizing antibodies. These results suggest that periodontal infection, especially bacterial endotoxinemia, is associated with enhanced lipolysis and subsequent up-regulation of circulating TG in Japanese with midrange BMI.

Pitavastatin decreases the expression of endothelial lipase both in vitro and in vivo

AIMS

In addition to their cholesterol-lowering effect, statins increase high-density lipoprotein cholesterol (HDL-C) levels. Endothelial lipase (EL) is a regulator of plasma HDL-C levels. In the present study, the effects of statins on EL expression were investigated.

METHODS AND RESULTS

The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin suppressed basal and cytokine-treated EL expression in endothelial cells. Concomitant treatment with mevalonate or geranylgeranyl pyrophosphate completely reversed the inhibitory effect of pitavastatin, suggesting that geranylgeranylated proteins are involved in the inhibition of EL expression by statins. Inhibition of RhoA activity by overexpression of a dominant-negative mutant of RhoA or a Rho kinase inhibitor decreased EL levels. Pitavastatin reduced phospholipase activities of endothelial cells, and concomitant treatment with mevalonate reversed its inhibitory effect. Pitavastatin reduced RhoA activity and EL expression in mouse tissues. Furthermore, plasma EL concentrations in human subjects were measured by enzyme-linked immunosorbent assays. Plasma EL levels were negatively associated with plasma HDL levels in 237 patients with cardiovascular diseases, and pitavastatin treatment reduced plasma EL levels and increased HDL-C levels in 48 patients with hypercholesterolaemia.

CONCLUSION

These findings suggest that statins can reduce EL expression in vitro and in vivo via inhibition of RhoA activity. The inhibition of EL expression in the vessel wall may contribute to the anti-atherogenic effects of statins.

Identification of a suppressor element in the amelogenin promoter

Amelogenin expression is regulated in a cell-type- specific manner. Investigators have previously identified an enhancer element by using the 5' flanking sequence of the amelogenin promoter. However, the cell-type-specific regulation of the amelogenin gene remains poorly understood. In some genes, the first intron regulates tissue-specific expression. We hypothesized that intron 1 is important for the cell-type-specific regulation of amelogenin expression. We identified a suppressor element between -74 and -464. We also found enhancer activity in intron 1. Additionally, we found that the suppressor element in the promoter region suppressed intron 1 enhancer activity. The suppressor and the enhancers acted in an ameloblast-like cell line, but not in HeLa cells. Mutation of the Oct-1 binding sites reversed the suppressor activity, suggesting that Oct-1 sites are essential for suppression. These results suggest that Oct-1 and intron 1 may contribute to cell-type-specific amelogenin expression.