Estrogen receptor alpha genotype is associated with a reduced prevalence of radiographic hip osteoarthritis in elderly Caucasian women

We Challenged the Kellgren and Lawrence Radiographic Scoring Method and Came Up With Some Interesting Epidemiology for Osteoarthritis of the Hip

The study of hip osteoarthritis (OA) was slowed due to a lack of a good definition of radiographic hip OA (RHOA). The radiographic changes that occur in hip OA include both joint space narrowing and femoral head osteophytes in the early stages of the disease. This differs from OA of the knee, in which radiographic OA changes initially include osteophytes and only much later is joint space narrowing considered. The modified Croft Score is a novel scoring method for the hip that includes an equal weighting of femoral osteophytes and joint space narrowing. It is used to evaluate the epidemiology of prevalent, incident, and progressive RHOA. Use of the Croft Score found that mild changes in the femoral head or acetabulum could increase the risk of incident RHOA. Pioneering research on active shape modeling was undertaken to provide a more comprehensive assessment of hip shape and define actual femoral head shapes that increased the risk of RHOA. After defining RHOA, investigators found several risk factors, which included higher total hip bone mineral density and polymorphisms of the wnt/β-catenin signaling pathway, to be significant predictors of RHOA in elderly white women. Recently, it was found that RHOA was a strong risk factor for both all-cause mortality and cardiovascular disease mortality in elderly women.

Metabolic Syndrome, BMI, and Polymorphism of Estrogen Receptor-α in Peri- and Post-Menopausal Polish Women

The study aimed to investigate the association between the estrogen receptor alpha (ERα) polymorphism and the prevalence of metabolic syndrome (MetS) and obesity, as well as the coexistence of MetS and obesity, in peri- and post-menopausal Polish women. The study group consisted of 202 peri-menopausal and 202 post-menopausal women. ERα polymorphism: Xba I and Pvu II, MetS, BMI, and serum estrogen concentration were analyzed. MetS was found in 29% of the peri-menopausal women and in 21% of the post-menopausal women. BMI did not significantly differ between the peri- and post-menopausal women (≈42% were normal weight, ≈40% were overweight, and ≈18% were obese), (p = 0.82). Serum estrogen concentration in the peri-menopausal women was 91 ± 75 pg/mL, while that in the post-menopausal women was 17 ± 9. pg/mL, on average. Peri-menopausal women with AA and TT genotypes of the ERα polymorphism have a lower risk of obesity and MetS and the co-existence of obesity and MetS, whereas those women with the G or C allele have a higher risk of those health problems.

Estrogen receptor Alpha in human knee articular cartilage of healthy and osteoarthritic females

Objective

Estrogen and osteoarthritis association has previously been proposed. This study evaluates the presence of estrogen receptors (ER)-α in articular cartilage, and its association.

Methods

A prospective cohort study of women undergoing anterior cruciate ligament reconstruction (controls) or total knee arthroplasty (cases) was performed. Cartilage samples were processed and ER-α expression was quantified.

Results

Twenty patients were included: 12 cases and 8 controls. ER-α expression was higher in the case subjects.

Conclusion

Increased ER-α expression is associated with age, and degeneration. This suggests estrogen deficiency is a risk for osteoarthritis and is inversely related to proliferative looking chondrocytes.

Steroid hormone-related polymorphisms associate with the development of bone erosions in rheumatoid arthritis and help to predict disease progression: Results from the REPAIR consortium

Here, we assessed whether 41 SNPs within steroid hormone genes associated with erosive disease. The most relevant finding was the rheumatoid factor (RF)-specific effect of the CYP1B1, CYP2C9, ESR2, FcγR3A, and SHBG SNPs to modulate the risk of bone erosions (P = 0.004, 0.0007, 0.0002, 0.013 and 0.015) that was confirmed through meta-analysis of our data with those from the DREAM registry (P = 0.000081, 0.0022, 0.00074, 0.0067 and 0.0087, respectively). Mechanistically, we also found a gender-specific correlation of the CYP2C9_rs1799853T/T genotype with serum vitamin D3 levels (P = 0.00085) and a modest effect on IL1β levels after stimulation of PBMCs or blood with LPS and PHA (P = 0.0057 and P = 0.0058). An overall haplotype analysis also showed an association of 3 ESR1 haplotypes with a reduced risk of erosive arthritis (P = 0.009, P = 0.002, and P = 0.002). Furthermore, we observed that the ESR2, ESR1 and FcγR3A SNPs influenced the immune response after stimulation of PBMCs or macrophages with LPS or Pam3Cys (P = 0.002, 0.0008, 0.0011 and 1.97•10⁻⁷). Finally, we found that a model built with steroid hormone-related SNPs significantly improved the prediction of erosive disease in seropositive patients (P_RF+ = 2.46•10⁻⁸) whereas no prediction was detected in seronegative patients (P_RF− = 0.36). Although the predictive ability of the model was substantially lower in the replication population (P_RF+ = 0.014), we could confirm that CYP1B1 and CYP2C9 SNPs help to predict erosive disease in seropositive patients. These results are the first to suggest a RF-specific association of steroid hormone-related polymorphisms with erosive disease.

RIPK1 suppresses apoptosis mediated by TNF and caspase-3 in intervertebral discs

Background

Low back pain has become a serious social and economic burden and the leading cause of disability worldwide. Among a variety of pathophysiological triggers, intervertebral disc (IVD) degeneration plays a primary underlying role in causing such pain. Specifically, multiple independent endplate changes have been implicated in the initiation and progression of IVD degeneration.

Methods

In this study, we built a signaling network comprising both well-characterized IVD pathology-associated proteins as well as some potentially correlated proteins that have been associated with one or more of the currently known pathology-associated proteins. We then screened for the potential IVD degeneration-associated proteins using patients’ normal and degenerative endplate specimens. Short hairpin RNAs for receptor interacting serine/threonine kinase 1 (RIPK1) were constructed to examine the effects of RIPK1 knockdown in primary chondrocyte cells and in animal models of caudal vertebra intervertebral disc degeneration in vivo.

Results

RIPK1 was identified as a potential IVD degeneration-associated protein based on IVD pathology-associated signaling networks and the patients’ degenerated endplate specimens. Construction of the short hairpin RNAs was successful, with short-term RIPK1 knockdown triggering inflammation in the primary chondrocytes, while long-term knockdown triggered apoptosis through cleavage of the caspase 3 pathway, down-regulated NF-κB and mitogen-activating protein kinase (MAPK)s cascades, and decreased cell survival and inflammation. Animal models of caudal vertebra intervertebral disc degeneration further demonstrated that apoptosis was induced by up-regulation of tumor necrosis factor (TNF) accompanied by down-regulation of NF-κB and MAPKs cascades that are dependent on caspase and RIPK1.

Conclusions

These results provide proof-of-concept for developing novel therapies to combat IVD degeneration through interfering with RIPK1-mediated apoptosis signaling pathways especially in patients with RIPK1 abnormality.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1886-3) contains supplementary material, which is available to authorized users.

Expression of Genes and Their Polymorphism Influences the Risk of Knee Osteoarthritis

Introduction

Genetic factors including the level of expression of the fingerprint of genes involved in the development of bones and cartilage such as GDF-5 or ESR-α or CALM-1 are known to be strong determinants of the osteoarthritis (OA) in Caucasian and Oriental populations. Because of high prevalence of OA in Indian population and availability of limited genetic data, we determined whether similar genetic factors are involved in Indians as well.

Methods

A case control study was carried out involving 500 patients of knee OA and equal number of healthy controls. Genotyping analyses in whole blood, mRNA, and protein expressions in peripheral blood lymphocytes (PBLs) were performed using established protocols.

Results

Our results showed a significantly decreased level of mRNA and protein expressions for GDF-5, ESR-α, and CALM-1 genes in PBLs of OA cases when compared to healthy controls. The frequency of variant genotypes of these genes was also increased significantly in cases of OA compared to controls.

Conclusion

Our results demonstrated that the decrease in expression of GDF-5, ESR-α, and CALM-1 in PBLs and association of polymorphism in these genes may be important in predicting the severity and thereby the progression of OA in Indian population.

The genetics behind osteoarthritis: Asian focus

Osteoarthritis (OA), a degenerative joint disease, is the most common form of arthritis in the elderly. Problems arising from the condition are not only health, physical, and psychological, but also economical and social. OA is a complex disease causes by environmental factors (obesity, female gender, advancing age) and genetics. A strong genetic contribution to primary OA has been observed in several studies. Asian population is undoubtedly genetically different from European, whom most studies have been performed. This review systematically compares results of molecules involved with OA from studies performed on Asian and Caucasian populations. The clear differences between Asian and Caucasian populations may be from the sex- and ethnic-specific nature of the disease, as well as from the inclusion criteria of the studies. Global collaboration is highly significant in understanding genetic underlying OA. Knowledge gained from genetic study is important to the development of prevention and therapeutic intervention, and to identify individuals at risk of developing severe or progressive OA.

Cognitive Functions, Concentration of Endogenous Estradiol, Estrogen Receptor α (ERα) Polymorphism in Postmenopausal Women

BACKGROUND The goal of this study was to investigate the relationship between cognitive functions and the level of endogenous estradiol in postmenopausal women, according to which estrogen receptor α (ERα) polymorphism the woman carries. MATERIAL AND METHODS The study group consisted of 210 women. The inclusion criteria were: minimum 2 years after the last menstruation, FSH concentration 30 U/ml, and no dementia signs on Montreal Cognitive Assessment (MoCA). A computerized battery of Central Nervous System Vital Signs (CNS VS) test was used to diagnose cognitive functions. Genotyping of the ERa polymorphism was performed using a polymerase chain reaction and restriction enzymes (PCR-RFLP). Blood plasma was tested for FSH and estradiol (E2). Statistical analysis was performed using STATISTICA software. RESULTS A relationship was confirmed between standard scores for 3 cognitive functions: general memory, verbal memory, and processing speed, and the XbaI polymorphism in the women in the study. In the group of women with genotype TT PvuII, significant positive relationships were observed between the concentration of E2 and the standard scores of 3 cognitive functions: general memory, verbal memory, and processing speed. In the group of women with genotype TC PvuII, significant negative correlations were found between the concentration of E2 and the standard scores of 4 cognitive functions: NCI, general memory, verbal memory, and processing speed. CONCLUSIONS ERα polymorphism exerted an effect on the interaction between the concentration of estradiol and the results for cognitive functions. The concentration of estradiol did not depend on Xba1 and PvuII polymorphisms. The results for cognitive functions depended on which Xba1 polymorphism the woman carried.

Estrogen receptor gene polymorphism in patients with degenerative lumbar scoliosis

OBJECTIVE

To examine the association between development of degenerative lumbar scoliosis (DLS) and sex hormones.

METHODS

We investigated the association between DLS and estrogen receptor alpha (ERα) gene polymorphisms in 184 patients with a diagnosis of DLS, by determining the presences of the Pvu II and Xba I polymorphisms, measuring bone mineral densities at the lumbar spine (LSBMD) and femoral neck (FNBMD), and by investigating biochemical markers of bone turnover and comparing these results with those of 220 healthy normal controls.

RESULTS

Genotype frequencies in DLS patients and controls revealed a significant difference for the Pvu II polymorphism only (p = 0.0287). No significant difference was found between the DLS and control groups with respect to the Xba I polymorphism, bone mineral density (BMD), or biochemical markers. Furthermore, no significant association was observed between the Pvu II polymorphism and BMD, lumbar scoliosis, lateral listhesis, or biochemical markers in patients with DLS.

CONCLUSION

These results suggest that the ERα Pvu II polymorphism influences the prevalence of DLS.

Genetic effects of common polymorphisms in estrogen receptor alpha gene on osteoarthritis: a meta-analysis

OBJECTIVE

The estrogen receptor alpha (ESR1) gene has been implicated in the etiology of osteoarthritis (OA). However, the results are conflicting. We assessed the association of three common ESR1 polymorphisms, rs2234693, rs9340799 and rs2228480, with OA in this meta-analysis.

METHODS

A comprehensive search was performed to identify related studies. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using fixed or random effects model.

RESULTS

15 studies (7036 cases and 9669 controls) for rs2234693 polymorphism, 14 studies (3904 cases and 6991 controls) for rs9340799 and 3 studies (331 cases and 619 controls) for rs2228480 polymorphism were identified. The final results indicated that the G allele in ESR1 rs9340799 was associated with decreased OA risk (GG+GA vs. AA: OR=0.878, 95% CI=0.792-0.972, P=0.012; G vs. A: OR=0.902, 95% CI=0.836-0.975, P=0.009). The A allele in rs2228480 might be associated with increased OA risk. But no significant association of rs2234693 polymorphism with OA susceptibility was observed.

CONCLUSIONS

This meta-analysis indicates rs9340799 and rs2228480 rather than rs2234693 polymorphisms are associated with the incidence of OA. Some stable associations should be further confirmed in future.

Estrogen receptor α (ESR1) IVS1-397T>C polymorphism lowers risk of fracture

BACKGROUND

Genetic factors are reported to affect fracture incidence. Many groups have explored the correlation of fracture risk with ESR1 IVS1-397T>C. The observed associations, however, are largely inconsistent. This meta-analysis of data from early-released studies was performed in an effort to determine the role of IVS1-397T>C in fracture.

METHODS

Relevant studies were searched through Pubmed, Embase, ScienceDirect, and Wiley Online Library databases. 16 studies meeting all selection criteria were finally identified. We calculated ORs with 95% CIs to assess risk of fracture. Subgroup analyses were performed by subtype, ethnicity and gender.

RESULTS

Data on 2916 cases and 19170 controls were analyzed in the meta-analysis. Overall, we found moderately decreased risk in association with IVS1-397 CC genotype (OR = 0.82, 95% CI = 0.73-0.92; OR = 0.84, 95% CI = 0.76-0.94). The decrease persisted in both hip fracture (OR = 0.82, 95% CI = 0.71-0.94; OR = 0.83, 95% CI = 0.73-0.94) and vertebral fracture (OR = 0.67, 95% CI = 0.50-0.91; OR = 0.78, 95% CI = 0.64-0.97; OR = 0.82, 95% CI = 0.68-0.98) when data were stratified by subtype. We also found a significant trend of decreasing risk in relation to the CC genotype in Caucasian, male and female. All fixed-effects meta-analysis results were homogeneous.

CONCLUSION

The meta-analysis demonstrates that risk of fracture seems likely to be decreased due to IVS1-397 CC or CT genotype.

Genetic polymorphism of the estrogen receptor alpha gene and susceptibility to osteoarthritis: evidence based on 15,022 subjects

OBJECTIVE

Several lines of evidence suggest that estrogen receptor alpha (ER-α) gene polymorphism may influence the development of osteoarthritis (OA). However, the results are inconsistent. The aim of this study was to explore using a meta-analysis whether rs2234693 (ER-α PvuII T/C) polymorphism confers significant susceptibility to OA.

METHODS AND RESULTS

A systematic search of all relevant studies published through 17 August 2014 was conducted using the PubMed, Web of Science, Embase, Cochrane database, Current Controlled Trials, Clinicaltrials.gov, Chinese Clinical Trial Registry, CBMdisc, CNKI and Google Scholar. All statistical analyses were done with Review Manager 5.1.4. Twelve articles involving 15 studies were included in the final meta-analysis, which contained 6417 OA cases and 8605 controls. Overall, no significant association was found between the rs2234693 polymorphism and OA risk when all studies were pooled into the meta-analysis (for C allele vs. T allele: OR = 0.99, 95% CI = 0.94-1.04, p = 0.63; for C/C vs. T/T: OR = 0.97, 95% CI = 0.87-1.08, p = 0.53; for C/C vs. T/C + T/T: OR = 0.96, 95% CI = 0.88-1.06, p = 0.43; for C/C + T/C vs. T/T: OR = 1.00, 95% CI = 0.89-1.14, p = 0.94). In the subgroup analysis, significant association was found between the rs2234693 polymorphism and the OA risk in the knee osteoarthritis (KOA) group (for C/C + T/C vs. T/T: OR = 1.15, 95% CI = 1.02-1.29, p = 0.02).

CONCLUSIONS

The present meta-analysis suggests that the rs2234693 polymorphism is associated with an increased KOA risk. Additional well designed genome-wide association studies are required to confirm the result.

Association between polymorphisms in the estrogen receptor alpha gene and osteoarthritis susceptibility: a meta-analysis

Background

Osteoarthritis (OA) is a common chronic disease of the joints. Genetic factors may play a role in its development, and polymorphisms in the estrogen receptor alpha gene (ERα) have been associated with OA. However, previous studies into this relationship have reported inconsistent results, so we aimed to systematically review the association between ERα polymorphisms and OA susceptibility.

Methods

We conducted a comprehensive literature search of Ovid MEDLINE, EMBASE, CBM, and PubMed databases, and Google scholar, and identified 11 eligible studies that examined the association between ERα polymorphisms and OA susceptibility. We carried out a meta-analysis of these studies based on ERα XbaI (rs9340799) and PvuII (rs2234693) genotypes.

Results

Seventeen comparisons involving 10 European and seven Asian populations of 5,325 OA patients and 10,834 controls were included in the study. The ERα XbaI polymorphism were significantly associated with OA in Europeans (AA vs. AG + GG: OR = 1.17, 95% confidence interval (CI) = 1.02–1.34, P = 0.03; AG vs. AA + GG: OR = 0.86, 95% CI = 0.75–0.99, P = 0.04) but not in Asian populations. No association was found between OA and the ERα PvuII polymorphism in any population (C vs. T, OR = 0.98, 95% CI = 0.93–1.03, P = 0.37; CC vs. TT + CT, OR = 0.97, 95% CI = 0.89–1.06, P = 0.55; CT vs. CC + TT, OR = 0.99, 95% CI = 0.92–1.06, P = 0.75; TT vs. CC + CT, OR = 1.01, 95% CI =0.92–1.12, P = 0.79).

Conclusions

This study suggested that there may be a weak relationship between the ERα XbaI polymorphism and OA in Europeans but not Asians, and that the ERα PvuII polymorphism was not associated with OA in either population. However, large well-designed studies are necessary to confirm these results in more homogeneous populations.

Association between estrogen receptor-alpha gene PvuII and XbaI polymorphisms and osteoarthritis risk: a meta-analysis

Estrogen receptor-alpha (ER-α) gene PvuII (T/C) and XbaI (A/G) polymorphisms have been hypothesized to be associated with osteoarthritis (OA) risk by several epidemiological studies, however, the available results were inconclusive and conflicting. We conducted a meta-analysis of 10 case-control studies that included 3328 osteoarthritis cases and 6390 case-free controls. We assessed the strength of the association, using odds ratios (ORs) with 95% confidence intervals (CIs). This meta-analysis showed that the ER-α PvuII and XbaI polymorphisms were not associated with OA risk in overall population. For the PvuII (T/C) polymorphism, however, in the subgroup analysis by country, a significantly reduced risk was observed among Chinese (TC vs. CC: OR = 0.73, 95% CI 0.54-0.99, I (2) = 0%, P heterogeneity = 0.498; dominant model, OR = 0.73, 95% CI = 0.55-0.98, I (2) = 0%, P heterogeneity = 0.555). For the XbaI (A/G) polymorphism, when stratifying by sample size, a significantly elevated risk was found in sample size ≤ 500 (AA vs. GG: OR = 2.60, 95% CI 1.10-6.18, I (2) = 42.9%, P heterogeneity = 0.135; dominant model: OR = 2.04, 95% CI 1.12-3.71, I (2) = 11.4%, P heterogeneity = 0.341; and recessive model: OR = 1.69, 95% CI 1.12-2.55, I (2) = 40.2%, P heterogeneity = 0.154). No publication bias was found in the present study. This meta-analysis suggests that ER-α PvuII (T/C) polymorphism may be associated with a reduced OA risk among Chinese and the XbaI (A/G) polymorphism may not be associated with OA risk, while the observed increase in OA risk for XbaI polymorphism may be due to small-study bias.

Polymorphisms in the gene encoding estrogen receptor alpha are associated with osteoarthritis in Han Chinese women

Polymorphisms in the Xba I and Pvu II restriction enzyme recognition sites in the estrogen receptor-alpha gene (ESR1) have been associated with multiple diseases, including osteoarthritis. To determine whether such polymorphisms are associated with osteoarthritis in a Han Chinese population, 98 women with osteoarthritis and 196 healthy women were genotyped by PCR-RFLP of ESR1 with Xba I and Pvu II. Absence of a restriction polymorphism is indicated as an X or P allele; presence of the restriction polymorphism is indicated as an x or p allele. Clinical information was collected on each participant, including body weight, body mass index (BMI), knee radiograms, and bone mineral density (BMD). Body weight and BMI were higher for each Xba I genotype (all P < 0.05) in individuals with osteoarthritis compared to controls (p < 0.05). Femoral BMD was also significantly higher in the osteoarthritis group (p < 0.05). Additionally, the xx genotype for ESR1 was a significant risk factor for osteoarthritis (OR=1.98, 95% CI: 1.13~4.20, p=0.036). Thus, consistent with findings in other populations, the estrogen receptor genotype xx appears to be associated with susceptibility to osteoarthritis among Han Chinese women.

Association of rs9340799 polymorphism in estrogen receptor alpha gene with the risk of osteoarthritis: evidence based on 8,792 subjects

Osteoarthritis (OA) is one of the most common skeletal disease, which seriously affects the quality of life of patients, particularly in the middle-aged and elderly individuals. We aimed to explore whether rs9340799 [estrogen receptor alpha (ER-α) XbaI A/G] polymorphism was associated with OA using a meta-analysis. A literature search for eligible studies published before March 28, 2014 was conducted in the PubMed, Web of Science, Embase, Cochrane database, Current Controlled Trials, Clinicaltrials.gov, Chinese Clinical Trial Registry, CBMdisc, CNKI, Google Scholar and Baidu Library. The association between the rs9340799 polymorphism and OA risk was assessed by odds ratios (ORs) together with their 95 % confidence intervals (CIs). A total of 663 articles were found. After article review and quality assessment, 10 articles involving 2,924 OA cases and 5,868 controls were included in the final meta-analysis. The combined evidence suggested that rs9340799 polymorphism contributed significantly to an increased risk of OA (for G allele vs. A allele: OR = 1.21, 95 % CI 1.03-1.43, p = 0.02; for G/G vs. A/A: OR = 1.30, 95 % CI 1.07-1.57, p = 0.009). In the subgroup analyses, significant associations were found between the rs9340799 polymorphism and the OA risk in the European group, Asian group, and knee osteoarthritis group, respectively. These results suggested that the rs9340799 polymorphism might be associated with the risk of OA. However, the results should be interpreted with caution because of the publication bias.

Genetic influences on hand osteoarthritis in Finnish women--a replication study of candidate genes

Objectives

Our aims were to replicate some previously reported associations of single nucleotide polymorphisms (SNPs) in five genes (A2BP1, COG5, GDF5, HFE, ESR1) with hand osteoarthritis (OA), and to examine whether genes (BCAP29, DIO2, DUS4L, DVWA, HLA, PTGS2, PARD3B, TGFB1 and TRIB1) associated with OA at other joint sites were associated with hand OA among Finnish women.

Design

We examined the bilateral hand radiographs of 542 occupationally active Finnish female dentists and teachers aged 45 to 63 and classified them according to the presence of OA by using reference images. Data regarding finger joint pain and other risk factors were collected using a questionnaire. We defined two hand OA phenotypes: radiographic OA in at least three joints (ROA) and symptomatic DIP OA. The genotypes were determined by PCR-based methods. In statistical analysis, we used SNPStats software, the chi-square test and logistic regression.

Results

Of the SNPs, rs716508 in A2BP1 was associated with ROA (OR = 0.7, 95% CI 0.5–0.9) and rs1800470 in TGFB1 with symptomatic DIP OA (1.8, 1.2–2.9). We found an interaction between ESR1 (rs9340799) and occupation: teachers with the minor allele were at an increased risk of symptomatic DIP OA (2.8, 1.3–6.5). We saw no association among the dentists. We also found that the carriage of the COG5 rs3757713 C allele increased the risk of ROA only among women with the BCAP29 rs10953541 CC genotype (2.6; 1.1–6.1). There was also a suggestive interaction between the HFE rs179945 and the ESR1 rs9340799, and the carriage of the minor allele of either of these SNPs was associated with an increased risk of symptomatic DIP OA (2.1, 1.3–2.5).

Conclusions

Our results support the earlier findings of A2BP1 and TBGF1 being OA susceptibility genes and provide evidence of a possible gene-gene interaction in the genetic influence on hand OA predisposition.

Association of single nucleotide polymorphisms in estrogen receptor alpha gene with susceptibility to knee osteoarthritis: a case-control study in a Chinese Han population

Osteoarthritis (OA) is the most prevalent form of arthritis and its multifactorial nature has been increasingly recognized. Genetic factors play an important role in OA etiology and estrogen receptor alpha (ESR1) gene polymorphisms may be involved. This study tried to explore whether the ESR1 gene single nucleotide polymorphisms (SNPs) were associated with primary knee OA in the Chinese Han population. Two SNPs, rs2234693 and rs9340799, were genotyped in 469 cases and 522 controls. Rs2234693 was associated with knee OA in the dominant genetic model (TT + TC versus CC) (P = 0.025) and a higher T allele frequency existed (P = 0.047) among females. The combined genotype (TT + TC) (P = 0.025) and T allele (P = 0.016) were related with mild knee OA only. For rs9340799, A allele was associated with knee OA in all subjects (P = 0.031) and females (P = 0.046). Statistical differences were detected in the dominant genetic model (AA + AG versus GG) among females (P = 0.030). The combined genotype (AA + AG) (P = 0.036) and A allele (P = 0.039) were merely correlated with mild knee OA. ESR1 gene is considerably associated with knee OA etiology in the Chinese Han population.

Association of genetic variants in estrogen receptor α with HCV infection susceptibility and viral clearance in a high-risk Chinese population

The purpose of this study was to test the hypothesis that genetic variants of estrogen receptor α (ERα) are associated with the outcomes of hepatitis C virus (HCV) infection. We genotyped the seven single nucleotide polymorphisms (SNPs) (rs2077647, rs9340799, rs2234693, rs1801132, rs9322354, rs2228480 and rs3798577) of ERα and conducted a case-control study in a high-risk Chinese population, including 429 HCV spontaneous clearance cases, 880 persistent infection cases and 1,174 uninfected controls. The C allele of rs2234693 was significantly associated with increased susceptibility to HCV infection [dominant model: adjusted odds ratio (OR) = 1.377, 95% confidence interval (CI) =1.126-1.778], and the risk effect remained significant among the younger (≤55 years) and hemodialysis subjects (all P < 0.007). The other three SNPs variant genotypes also showed significant correlation with elevated risk of HCV infection in different strata (rs2077647 in males; rs9340799 in blood donors; rs1801132 in younger subjects; all P < 0.007). It was also discovered that carriage of rs2228480 A allele was more prone to develop persistent HCV infection (dominant model: adjusted OR = 1.203, 95% CI = 1.154-1.552), and the risk effect was more evident in females and blood donors (all P < 0.007). Haplotype analyses (rs2077647, rs9340799 and rs2234693) showed that, compared with the most frequent haplotype TAT, CAC played a risk effect in subgroups of younger (P = 3.24 × 10(-3)) and male (P = 5.51 × 10(-4)), whereas CAT expressed a protective effect in females (P = 2.27 × 10(-4)) for HCV infection susceptibility. We first report that these SNPs (rs2077647, rs9340799, rs2234693, rs1801132 and rs2228480) in ERα can influence the outcomes of HCV infection in a high-risk Chinese population.

Association between estrogen receptor α gene (ESR1) PvuII (C/T) and XbaI (A/G) polymorphisms and hip fracture risk: evidence from a meta-analysis

Background and Objective

Genetic factors are important in the pathogenesis of fractures. Notably, estrogen receptor α (ESR1) has been suggested as a possible candidate gene for hip fractures; however, published studies of ESR1 gene polymorphisms have been hampered by small sample sizes and inconclusive or ambiguous results. The aim of this meta-analysis is to investigate the associations between two novel common ESR1 polymorphisms (intron 1 polymorphisms PvuII-rs2234693: C>T and XbaI-rs9340799: A>G) and hip fracture.

Methods

Crude odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association.

Results

Five case-control and three cohort studies were assessed, including a total of 1,838 hip fracture cases and 14,972 healthy controls. This meta-analysis revealed that the PvuII T allele is a highly significant risk factor for hip fracture susceptibility, with an effect magnitude similar in male and pre-menopausal and post-menopausal female patients. In stratified analysis based on ethnicity, the PvuII T allele remained significantly correlated with increased risk of hip fracture in Caucasian populations; this correlation, however, was not found in Asian populations. Unlike the PvuII polymorphism, we did not find significant differences in the XbaI (A>G) polymorphism allele or genotype distributions of hip fracture patients and controls. We also found no obvious association between the XbaI polymorphism and hip fracture in any of the racial or gender subgroups.

Conclusion

Our findings show that the ESR1 PvuII T allele may increase the risk of hip fracture and that the XbaI polymorphism is not associated with hip fracture.

Targeting bone alleviates osteoarthritis in osteopenic mice and modulates cartilage catabolism

OBJECTIVE

Subchondral bone modifications occur early in the development of osteoarthritis (OA). The level of bone resorption might impact cartilage remodeling. We therefore assessed the in vivo and in vitro effects of targeting bone resorption in OA and cartilage metabolism.

METHODS

OA was induced by meniscectomy (MNX) in ovariectomized osteopenic mice (OP) treated with estradiol (E2), pamidronate (PAM), or phosphate buffered saline (PBS) for 6 weeks. We assessed the subchondral bone and cartilage structure and the expression of cartilage matrix proteases. To assess the involvement of bone soluble factors in cartilage metabolism, supernatant of human bone explants pre-treated with E2 or PAM were transferred to cartilage explants to assess proteoglycan release and aggrecan cleavage. OPG/RANKL mRNA expression was assessed in bone explants by real-time quantitative PCR. The role of osteoprotegerin (OPG) in the bone-cartilage crosstalk was tested using an OPG neutralizing antibody.

RESULTS

Bone mineral density of OP mice and osteoclast number were restored by E2 and PAM (p<0.05). In OP mice, E2 and PAM decreased ADAMTS-4 and -5 expression, while only PAM markedly reduced OA compared to PBS (2.0±0.63 vs 5.2±0.95; p<0.05). OPG/RANKL mRNA was increased in human bone explants treated with both drugs (2.2-3.7-fold). Moreover, supernatants from bone explants cultured with E2 or PAM reduced aggrecan cleavage and cartilage proteoglycan release (73±8.0% and 80±22% of control, respectively, p<0.05). This effect was reversed with osteoprotegerin blockade.

CONCLUSION

The inhibition of bone resorption by pamidronate in osteopenic mice alleviates the histological OA score with a reduction in the expression of aggrecanases. Bone soluble factors, such as osteoprotegerin, impact the cartilage response to catabolic factors. This study further highlights the importance of subchondral bone in the regulation of joint cartilage damage in OA.

Association of estrogen receptor gene polymorphism in patients with degenerative lumbar spondylolisthesise

OBJECTIVE

The purpose of this study was to investigate the possible association of estrogen receptor alpha (ERα) gene polymorphisms in a cohort of degenerative spondylolisthesis (DS) patients.

METHODS

Accordingly, the authors examined the association between DS and ERα gene polymorphisms in 174 patients diagnosed with DS. The Pvu II and Xba I polymorphisms, bone mineral density at the lumbar spine and femoral neck, and biochemical markers were analyzed and compared in the 174 patients with DS and 214 patients with spinal stenosis (SS).

RESULTS

A comparison of genotype frequencies in DS and SS patients revealed a significant difference for the Pvu II polymorphism only (p=0.0452). No significant difference was found between these two groups with respect to the Xba I polymorphism, BMD or biochemical markers. No significant association was found between the Pvu II polymorphism of ERα and BMD, vertebral slip or biochemical markers in patients with DS.

CONCLUSION

These results suggest that the ERα gene polymorphism using Pvu II restriction enzyme influences the prevalence of DS.

Analysis of estrogen receptor alpha gene haplotype in Mexican mestizo patients with primary osteoarthritis of the knee

The aim of this work was to test the association between estrogen receptor α gene (ERα) polymorphism and primary osteoarthritis (OA) of the knee in Mexican mestizo patients. A case-control study was conducted. Cases were patients >40 years of age, with a body mass index (BMI) ≤ 27 and radiologic score for OA of the knee of ≥2 according to Kellgren-Lawrence scale, and controls were subjects >40 years age with a radiologic score <2. Two restriction fragment length polymorphisms, PvuII (T/C; rs2234693), and XbaI (A/G; rs9340799), of the ERα were analyzed. Allelic haplotypes were constructed and non-conditional logistic regression was developed to evaluate risk magnitude through odds ratios (ORs) and 95% Confidence intervals (95% CI). Three different allelic haplotypes were identified: TA; CG, and CA. Unadjusted analysis of the haplotypes did not show significant associations; nonetheless, when data were adjusted for gender, age, and BMI, a significant decrease risk was observed for CG haplotype (OR [95% CI]) = 0.5 (0.3-0.9)] (P = 0.04). These results suggest that ERα gene CG haplotype could be associated with a reduced risk of primary knee OA in Mexican mestizo population.

Effects of pulsed electromagnetic fields on cartilage apoptosis signalling pathways in ovariectomised rats

PURPOSE

The purpose of this study was to determine the effect of exposure to pulsed electromagnetic fields (PEMF) on modulation of the cartilage apoptosis signalling pathway in ovariectomised rats by monitoring the expression of mRNA of X-linked inhibitor of apoptosis protein (XIAP) and Bax.

METHODS

Forty-eight female Sprague-Dawley rats (250 ± 50 g) were randomly assigned to one of four groups: ovariectomy with PEMF treatment (PEMF group), ovariectomy with oestradiol (E2) treatment (oestrogen group), ovariectomy control (OVX group) and sham group. The ovariectomy model was prepared by surgical resection of the ovaries. After a three-month intermission, animals in the PEMF and oestrogen groups received treatment for 30 days; then serum 17β-oestradiol levels, chondrocyte morphology, and XIAP and Bax mRNA expression in knee joint cartilage were analysed.

RESULTS

The results showed different chondrocyte formation in each group. Serum E2 content in the PEMF and oestrogen groups was significantly higher than in the OVX group (p < 0.05). The expression of XIAP mRNA in the PEMF and oestrogen groups was significantly up-regulated compared to the OVX group, while that of Bax mRNA was significantly down-regulated (p < 0.05). The correlation between E2 level and expression of Bax mRNA was positive (0.506) and statistically significant (p < 0.001).

CONCLUSION

These data demonstrate that PEMF can up-regulate XIAP mRNA expression and down-regulate Bax mRNA expression in ovariectomised rats. Changes in XIAP and Bax mRNA expression may be the mechanism by which PEMF therapy affects postmenopausal osteoarthritis.

Osteoarthritis hip joints in Japan: involvement of acetabular dysplasia

BACKGROUND

We conducted a nationwide epidemiologic study regarding hip osteoarthritis (OA) in Japan, and a previous report found these patients to be unique in comparison to Caucasians. This report focused on the data regarding each hip joint, and the involvement of acetabular dysplasia with hip OA was analyzed.

METHODS

Seven hundred twenty OA hips were examined. Sixty-five joints with osteonecrosis of the femoral head and 215 non-OA contralateral joints of the unilateral patients were examined as controls. The revised system of stage classification for hip OA of the Japanese Orthopedic Association (JOA) was used according to the reproducibility in order to ensure reliable data from the multiple institutions. The acetabular dysplasia indexes were also chosen according to the reproducibility and measured in the radiograph of bilateral hip joints. The clinical score was assessed using the JOA scoring system. The relative risk of the grade of acetabular dysplasia indexes for hip OA was calculated as the odds ratio and the 95% confidence interval.

RESULTS

The stage of the OA joints deteriorated with increasing age. The clinical scores also decreased. The grade of the acetabular dysplasia indexes of the OA joints was significantly higher than that of the control joints. Each index of acetabular dysplasia demonstrated significantly increased odds ratios for hip OA. Among the OA joints, the deterioration of the OA stage was found to be significantly associated with an increasing grade of acetabular dysplasia. The odds ratio for OA deterioration in the acetabular dysplasia index was also obtained. The joints of females tended to have a higher grade and prevalence of acetabular dysplasia than those of males.

CONCLUSIONS

These findings confirmed a high prevalence of acetabular dysplasia in hip OA joints in Japan. Acetabular dysplasia was one of the most important factors associated with hip OA.

Genetic epidemiology of hip and knee osteoarthritis

Osteoarthritis (OA) is the most common cause of arthritis and represents an enormous healthcare burden in industrialized societies. Current therapeutic approaches for OA are limited and are insufficient to prevent the initiation and progression of the disease. Genetic studies of patients with OA can help to unravel the molecular mechanisms responsible for specific disease manifestations, including joint damage, nociception and chronic pain. Indeed, these studies have identified molecules, such as growth/differentiation factor 5, involved in signaling cascades that are important for the pathology of joint components. Genome-wide association studies have uncovered a likely role in OA for the genes encoding structural extracellular matrix components (such as DVWA) and molecules involved in prostaglandin metabolism (such as DQB1 and BTNL2). A ∼300 kilobase region in chromosome 7q22 is also associated with OA susceptibility. Finally, the identification of individuals at a high risk of OA and of total joint arthroplasty failure might be facilitated by the use of combinations of genetic markers, allowing for the application of preventive and disease-management strategies.

Common variations in estrogen-related genes are associated with severe large-joint osteoarthritis: a multicenter genetic and functional study

OBJECTIVE

Several lines of evidence suggest that estrogens influence the development of osteoarthritis (OA). The aim of this study was to explore the association of two common polymorphisms within the aromatase (CYP19A1) and estrogen receptor (ER) alpha (ESR1) genes with severe OA of the lower limbs.

METHODS

The rs1062033 (CYP19A1) and rs2234693 (ESR1) single nucleotide polymorphisms were genotyped in 5528 individuals (3147 patients with severe hip or knee OA, and 2381 controls) from four centres in Spain and the United Kingdom. Gene expression was measured in femoral bone samples from a group of patients.

RESULTS

In the global analysis, both polymorphisms were associated with OA, but there was a significant sex interaction. The GG genotype at rs1062033 was associated with an increased risk of knee OA in women [odds ratio (OR) 1.23; P=0.04]. The CC genotype at rs2234693 tended to be associated with reduced OA risk in women (OR 0.76, P=0.028, for knee OA; OR=0.84, P=0.076 for hip OA), but with increased risk of hip OA in men (OR 1.28; P=0.029). Women with unfavourable genotypes at both loci had an OR of 1.61 for knee OA (P=0.006). The rs1062033 genotype associated with higher OA risk was also associated with reduced expression of the aromatase gene in bone.

CONCLUSIONS

Common genetic variations of the aromatase and ER genes are associated with the risk of severe OA of the large joints of the lower limb in a sex-specific manner. These results are consistent with the hypothesis that estrogen activity may influence the development of large-joint OA.

Osteoarthritis associated with estrogen deficiency

Osteoarthritis (OA) affects all articular tissues and finally leads to joint failure. Although articular tissues have long been considered unresponsive to estrogens or their deficiency, there is now increasing evidence that estrogens influence the activity of joint tissues through complex molecular pathways that act at multiple levels. Indeed, we are only just beginning to understand the effects of estrogen deficiency on articular tissues during OA development and progression, as well as on the association between OA and osteoporosis. Estrogen replacement therapy and current selective estrogen receptor modulators have mixed effectiveness in preserving and/or restoring joint tissue in OA. Thus, a better understanding of how estrogen acts on joints and other tissues in OA will aid the development of specific and safe estrogen ligands as novel therapeutic agents targeting the OA joint as a whole organ.

Attempt to replicate published genetic associations in a large, well-defined osteoarthritis case-control population (the GOAL study)

OBJECTIVE

Published studies have tested over 90 genes for association with osteoarthritis (OA), but few positives reported have been independently replicated. Using a new case-control study, our aim was to attempt the replication of findings from 12 genes reported to have significant genetic association with OA and to further examine the role of genetic variation in six of these genes.

METHODS

A case-control study was undertaken in Nottingham, UK. Hospital-referred index cases with symptomatic, radiographic OA (ROA) of the knee (n=1040) or hip (n=1004) were recruited. Asymptomatic controls (n=1123) were recruited from intravenous urography waiting lists and screened for radiographic hip and knee OA. Sixty-eight polymorphisms were genotyped in IL1A, IL1B, IL1RN, IL4R, IL6, COL2A1, ADAM12, ASPN, IGF1, TGFB1, ESR1 and VDR. Statistical analysis compared allele or genotype frequencies of these polymorphisms in all asymptomatic controls and the subset of controls without ROA vs all OA, knee OA and hip OA. The analyses were adjusted for age, gender and body mass index.

RESULTS

We were unable to replicate any of the published genetic associations investigated. Our extended exploratory analyses identified some associations between polymorphisms in TGFB1, IGF1 and IL1RN and OA; but the strength of evidence varied with the control group used.

CONCLUSION

Lack of replication is common and could be due to differences in study design, phenotype, populations examined or the occurrence of false positives in the initial study. Variants within TGFB1, IGF1 and IL1RN could have a role in OA susceptibility; however, replication of these findings is required in an independent study.