Estrogen replacement therapy modulation of the insulin-like growth factor system in monkey knee joints

Lower serum testosterone is associated with increased likelihood of arthritis

Studies have suggested that serum testosterone levels may be strongly correlated with the pathogenesis of arthritis. Therefore, the aim of this study was to assess the relationship between serum testosterone levels and arthritis in US adults using the National Health and Nutrition Examination Survey (NHANES). We used the database from NHANES, 2013-2016 to perform a cross-sectional study. This study investigated the relationship between serum testosterone and arthritis using multivariate logistic regression models and also used smoothed curve fitting and generalized additivity models. A total of 10,439 adults were included in this analysis. A significant negative association between serum testosterone and arthritis was found in a linear regression analysis. The study showed that the arthritis group had lower testosterone levels than the non-arthritis group. The univariate multivariate analyses of Q4, using Q1 as a reference, all showed a significantly lower risk of developing arthritis. In subgroup analyses, the negative correlation between serum testosterone levels and arthritis was more significant in women and those with a body mass index (BMI) ≥ 30 kg/m2. After controlling for various variables, we found a significant association between serum testosterone and arthritis in this analysis. Further study of the relationship between testosterone and arthritis is necessary to clarify the specific mechanism of serum testosterone action on arthritis.

Sex-dependent variation in cartilage adaptation: from degeneration to regeneration

Despite acknowledgement in the scientific community of sex-based differences in cartilage biology, the implications for study design remain unclear, with many studies continuing to arbitrarily assign demographics. Clinically, it has been well-established that males and females differ in cartilage degeneration, and accumulating evidence points to the importance of sex differences in the field of cartilage repair. However, a comprehensive review of the mechanisms behind this trend and the influence of sex on cartilage regeneration has not yet been presented. This paper aims to summarize current findings regarding sex-dependent variation in knee anatomy, sex hormones' effect on cartilage, and cartilaginous degeneration and regeneration, with a focus on stem cell therapies. Findings suggest that the stem cells themselves, as well as their surrounding microenvironment, contribute to sex-based differences. Accordingly, this paper underscores the contribution of both stem cell donor and recipient sex to sex-related differences in treatment efficacy. Cartilage regeneration is a field that needs more research to optimize strategies for better clinical results; taking sex into account could be a big factor in developing more effective and personalized treatments. The compilation of this information emphasizes the importance of investing further research in sex differences in cartilage biology.

ULTRASONOGRAPHIC EVALUATION OF FEMORAL CARTILAGE THICKNESS IN PATIENTS WITH POLYCYSTIC OVARY SYNDROME

The aim of the study was to investigate knee cartilage thickness in polycystic ovary syndrome (PCOS) patients using ultrasonography and to assess the effects of sex steroids on osteoarthritis development. A total of 90 female patients were enrolled in the study, including 47 patients diagnosed with PCOS as study group and 43 patients admitted to our hospital for any other complaints as control group. Ultrasonographic evaluation of both knees was performed in all patients. The knee cartilage thickness was measured at lateral condyle, intercondylar area and medial condyle. The measurements were averaged for each region. The mean femoral cartilage thickness was greater in the study group compared with control group in all regions, with a statistically significant difference (p<0.005). In conclusion, we found PCOS patients to have greater mean cartilage thickness, supporting the possible effects of sex steroids on osteoarthritis development.

Up-regulation of type II collagen gene by 17β-estradiol in articular chondrocytes involves Sp1/3, Sox-9, and estrogen receptor α

The existence of a link between estrogen deprivation and osteoarthritis (OA) in postmenopausal women suggests that 17β-estradiol (17β-E2) may be a modulator of cartilage homeostasis. Here, we demonstrate that 17β-E2 stimulates, via its receptor human estrogen receptor α 66 (hERα66), type II collagen expression in differentiated and dedifferentiated (reflecting the OA phenotype) articular chondrocytes. Transactivation of type II collagen gene (COL2A1) by ligand-independent transactivation domain (AF-1) of hERα66 was mediated by "GC" binding sites of the -266/-63-bp promoter, through physical interactions between ERα, Sp1/Sp3, Sox9, and p300, as demonstrated in chromatin immunoprecipitation (ChIP) and Re-Chromatin Immuno-Precipitation (Re-ChIP) assays in primary and dedifferentiated cells. 17β-E2 and hERα66 increased the DNA-binding activities of Sp1/Sp3 and Sox-9 to both COL2A1 promoter and enhancer regions. Besides, Sp1, Sp3, and Sox-9 small interfering RNAs (siRNAs) prevented hERα66-induced transactivation of COL2A1, suggesting that these factors and their respective cis-regions are required for hERα66-mediated COL2A1 up-regulation. Our results highlight the genomic pathway by which 17β-E2 and hERα66 modulate Sp1/Sp3 heteromer binding activity and simultaneously participate in the recruitment of the essential factors Sox-9 and p300 involved respectively in the chondrocyte-differentiated status and COL2A1 transcriptional activation. These novel findings could therefore be attractive for tissue engineering of cartilage in OA, by the fact that 17β-E2 could promote chondrocyte redifferentiation.

KEY MESSAGES

17β-E2 up-regulates type II collagen gene expression in articular chondrocytes. An ERα66/Sp1/Sp3/Sox-9/p300 protein complex mediates this stimulatory effect. This heteromeric complex interacts and binds to Col2a1 promoter and enhancer in vivo. Our findings highlight a new regulatory mechanism for 17β-E2 action in chondrocytes. 17β-E2 might be an attractive candidate for cartilage engineering applications.

Menopause affects pain depending on pain type and characteristics

OBJECTIVE

Women are more affected than men by many chronic pain conditions, suggesting the effect of sex-related mechanisms in their occurrence. The role of gonadal hormones has been studied but with contrasting results depending on the pain syndrome, reproductive status, and hormone considered. The aim of the present study was to evaluate the pain changes related to the menopausal transition period.

METHODS

In this observational study, postmenopausal women were asked to evaluate the presence of pain in their life during the premenopausal and postmenopausal periods and its modification with menopause.

RESULTS

One hundred one women were enrolled and completed questionnaires on their sociodemographic status, pain characteristics, and evolution. The most common pain syndromes were headache (38%), osteoarticular pain (31%), and cervical/lumbar pain (21%). Pain was present before menopause in 66 women, ceased with menopause in 17, and started after menopause in 18. Data were used for cluster analysis, which allowed the division of participants into four groups. In the first, all women experienced headaches that disappeared or improved with menopause. The second group included osteoarticular pain; the pain improved in half of these women and remained stable in the other half. The third group had cervical/lumbar pain, which disappeared or improved with menopause in all. The fourth group presented different kinds of moderate pain, which worsened in all.

CONCLUSIONS

The present study provides preliminary data suggesting that menopause can affect pain depending on the painful condition experienced by the woman. This underlines the different interactions of menopause-related events with body structures involved in pain.

Etiology, assessment, and management of aromatase inhibitor-related musculoskeletal symptoms

Aromatase inhibitors (AIs) are recommended as adjuvant endocrine therapy for postmenopausal women with hormone-responsive breast cancer. With the widespread use of AI adjuvant endocrine therapy, a significant profile of musculoskeletal symptoms has emerged. Moderate to severe musculoskeletal symptoms have led some women to discontinue therapy, compromising the survival benefit. The etiology of AI-related musculoskeletal symptoms is poorly understood, which challenges development of effective management strategies. The purpose of this article is to describe AI-related musculoskeletal symptoms, review possible causes, provide assessment guidelines, and recommend management strategies based on the best available evidence. Little evidence exists for effective management strategies of AI-related musculoskeletal symptoms, and randomized clinical trials are needed to establish effective interventions. A thorough musculoskeletal assessment can help guide clinical decision making for the best individual management approach. Providers need to manage symptoms with the best available evidence to minimize symptom distress and maximize adherence to AI therapy.

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.

Animal models for osteoarthritis: the effect of ovariectomy and estrogen treatment - a systematic approach

OBJECTIVE

The prevalence of osteoarthritis (OA) increases dramatically in women after the age of 50. Animal models are used to study the effects of hormone depletion [by ovariectomy (OVX)] and estrogen treatment on OA. This review summarizes these animal studies, in order to get a better insight in the role of hormones on OA.

METHOD

The literature was systematically reviewed until May 2007. The results were divided into two parts: the effect of OVX on cartilage, and the effect of estrogen treatment on cartilage. Only studies with an appropriate control group (e.g., sham-operated) were included.

RESULTS AND DISCUSSION

Eleven out of 16 animal studies showed that OVX resulted in cartilage damage. When only studies using sexually mature animals were included, we saw that 11 out of 14 studies showed a detrimental effect, indicating considerable evidence for a relation between cartilage degeneration and OVX in mature animals. The effect of estrogen treatment was inconclusive with only 11 out of 22 animal studies reporting a beneficial effect on cartilage, whereas all six studies administering selective estrogen receptor modulators (SERMs) after OVX described protective effects. The discrepancy between the studies may be caused by the large variation in experimental set-up. We suggested a list of quality criteria for animal models since standardisation of design and outcome parameters of animal experiments may help to compare different studies and to gain better insight in the role of hormones in the osteoarthritic process.

An update review of cellular mechanisms conferring the indirect and direct effects of estrogen on articular cartilage

OBJECTIVE

To review cellular mechanisms that have been proposed to mediate the indirect and direct effects of estrogen on articular cartilage, and to outline the remaining clinical questions that need to be clarified before utilizing the beneficial effects of estrogen for the prevention of osteoarthritis in early postmenopausal women.

DESIGN

Summary of original research papers and reviews listed in Pubmed (1980-2007).

RESULTS

Estrogen receptors have been identified in articular chondrocytes from various animals and humans. Molecular studies showed that estrogen can elicit genomic and rapid non-genomic effects on various cell types, including chondrocytes, and the latter effects are only inducible in females. In addition to direct effects, estrogen can also affect the homeostasis of articular cartilage by modulating the expression/production of different molecules such as various growth factors, inflammatory cytokines, matrix metalloproteinases, and reactive oxygen species. Moreover, in vivo observation argues for the notion that inhibition of subchondral bone turnover is also part of the mechanisms by which estrogen (and antiresorptive agents in general) can protect against joint degradation. Published studies undertaken at cellular, tissue, and in vivo levels illustrate that the effect of estrogen on cartilage may depend on the dose applied, the administration route, the time of initiation, and whether it is combined with a progestin.

CONCLUSIONS

The herein reviewed direct and indirect effects of estrogen on articular cartilage further corroborate the due consideration of estrogen therapy for maintaining not only bone but also cartilage health in postmenopausal women. Future studies in postmenopausal women are needed to clarify whether the efficacy of estrogen therapy can be further optimized by using other forms of estrogen, other progestins, or by initiating the therapy in the peri- or early postmenopausal period.

Effect of hormone therapy on risk of hip and knee joint replacement in the Women's Health Initiative

OBJECTIVE

To determine the effect of hormone therapy on arthroplasty rates.

METHODS

We examined data from the Women's Health Initiative placebo-controlled, double-blind, randomized trials. Community-dwelling women ages 50-79 years were enrolled at 40 US clinics. Women with prior arthroplasty were excluded, yielding a sample size of 26,321 subjects. Women who had had hysterectomies (n = 10,272) were randomly assigned to receive 0.625 mg/day conjugated equine estrogens (n = 5,076), or placebo (n = 5,196), with a mean followup of 7.1 years. Those who had not had hysterectomies (n = 16,049) were randomly assigned to receive estrogen plus progestin (n = 8,240), given as 0.625 mg/day conjugated equine estrogens plus 2.5 mg/day medroxyprogesterone acetate, or placebo (n = 7,809), with a mean followup of 5.6 years. Participants reported hospitalizations, and arthroplasties were identified by procedure codes. Arthroplasties due to hip fracture were censored. Cox proportional hazards regression was used to assess hazard ratios (HRs) and 95% confidence intervals (95% CIs) using intent-to-treat methods and outcome of time to first procedure.

RESULTS

In the estrogen-alone trial, women receiving hormone therapy had significantly lower rates of any arthroplasty (HR 0.84 [95% CI 0.70-1.00], P = 0.05). However, this effect was borderline statistically significant for hip arthroplasty (HR 0.73 [95% CI 0.52-1.03], P = 0.07), and not significant for knee arthroplasty (HR 0.87 [95% CI 0.71-1.07], P = 0.19). In the estrogen-plus-progestin trial, there was no association for total arthroplasty (HR 0.99 [95% CI 0.82-1.20], P = 0.92) or for individual hip (HR 1.14 [95% CI 0.83-1.57], P = 0.41) or knee (HR 0.91 [95% CI 0.72-1.15], P = 0.41) arthroplasties.

CONCLUSION

These data suggest that hormone therapy may influence joint health, but this observed decrease in risk may be limited to unopposed estrogen and may possibly be more important in hip than in knee osteoarthritis.

Oestrogens inhibit interleukin 1beta-mediated nitric oxide synthase expression in articular chondrocytes through nuclear factor-kappa B impairment

OBJECTIVES

To investigate the presence and functionality of oestrogen receptor alpha (ERalpha) in interleukin (IL)1beta-treated rabbit articular chondrocytes in culture, and to determine the mechanisms of 17beta oestradiol (E2) effects on IL1beta-induced inducible nitric oxide synthase (iNOS) expression.

METHODS

The presence and functionality of ERalpha were investigated by immunocytochemistry and transient expression of an E2-responsive reporter construct. iNOS expression and production were determined by transient expression of a chimeric iNOS promoter-luciferase construct and protein immunoblotting. Nitric oxide (NO) production was determined by the Griess reaction. DNA-binding activities of nuclear factor-kappaB (NF-kappaB) and activated protein 1 were determined by electrophoretic mobility shift assay (EMSA)-ELISA assays. Nuclear translocation of p65 was studied by immunocytochemistry.

RESULTS

ERalpha was identified in the nucleus of chondrocytes. ERalpha efficiently transactivated a transiently expressed E2-responsive construct. On IL1beta treatment, ERalpha partially diffused from its nuclear localisation into the cytoplasm and its transactivation ability was impaired. Nevertheless, E2, tamoxifen and raloxifene efficiently inhibited IL1beta-induced NO production (-34%, -31% and -36%, respectively). E2 decreased IL1beta-induced iNOS protein expression (-40%). Transient expression of an iNOS promoter construct strongly suggested that iNOS expression was inhibited at the transcriptional level, and EMSA-ELISA assays showed that E2 reduced (-60%) the IL1beta-induced p65 DNA-binding capacity. Finally, the p65 nuclear translocation induced by IL1beta was also strongly decreased by E2.

CONCLUSIONS

Our data support a reciprocal antagonism between oestrogens and IL1beta, ultimately resulting in the decrease of cytokine-dependent NO production through transcriptional inhibition of iNOS expression. This effect was associated with selective inhibition of p65 DNA binding and nuclear translocation.

Ovariectomy alters the structural and biomechanical properties of ovine femoro-tibial articular cartilage and increases cartilage iNOS

OBJECTIVE

To examine the effect of oestrogen depletion produced by surgical ovariectomy on the structural and biomechanical properties of ovine femoro-tibial articular cartilage (AC), and the production of inducible nitric oxide synthase (iNOS) and nitrotyrosine by these tissues.

METHODS

Six aged ewes were surgically ovariectomised (OVX), while six were used as unoperated controls. Dynamic biomechanical indentation testing of tibial plateau AC was performed at 26 weeks post-op. Histological sections of medial tibial plateau and lateral tibial plateau (LTP), medial and lateral femoral condyles (MFC, LFC) and patellar AC were examined for histopathology, toluidine blue staining intensity, and patterns of collagen birefringence intensity. Immunoreactivity for iNOS and nitrotyrosine was assessed in full-thickness biopsy plugs of LFC and patellar AC, and patellar AC explants were cultured to determine in vitro NO release.

RESULTS

Phase lag was reduced overall in LTP-AC of OVX sheep (10.9+/-2.2 degrees vs 12.1+/-2.3 degrees ; P<0.0001). Cartilage thickness was reduced in the LTP of OVX sheep (P=0.0002), in association with localised changes in dynamic shear modulus. Toluidine blue staining intensity was reduced in the patella, LFC, and MFC. Histological examination revealed greater histopathology scores in the MFC of OVX animals, and altered collagen birefringence intensity plots in the LTP. Immunostaining for iNOS was increased in patella AC (P=0.008), whilst nitrotyrosine immunoreactivity was increased in patella (P=0.03) and LFC (P<0.0001) AC. NO release by patellar AC explants was also elevated.

CONCLUSIONS

Oestrogen depletion induced by OVX caused regional thinning of femoro-tibial cartilage, with biomechanical and histological changes suggestive of a disturbance in the content and/or structural organisation of the proteoglycan and collagen macromolecular assembly. The observed up-regulation of cartilage iNOS suggests a possible mechanism for these matrix changes.

Osteoarthritis and the postmenopausal woman: Epidemiological, magnetic resonance imaging, and radiological findings

BACKGROUND

There is some observational evidence to suggest an effect of hormones on osteoarthritis (OA), especially in perimenopausal women.

OBJECTIVES

To review the epidemiological evidence for an effect of estrogen replacement therapy (ERT) on the incidence and prevalence of OA, especially radiological OA, and the effect of ERT on articular cartilage in women.

METHODS

The literature relating to these questions was reviewed using OVID Medline (1966 to March 2003).

RESULTS

Some studies which have suggested a protective effect of ERT on the incidence and prevalence of OA. However, many of the confidence intervals include unity. Although a protective effect also was seen on articular knee cartilage in long-term users of ERT compared with never users, no difference in change in cartilage was seen over 2 years.

CONCLUSIONS

There is weak epidemiological evidence suggesting a role for estrogen therapy in joint health in postmenopausal women. The data are more suggestive of an effect on large joint OA than small joint OA.

Factors influencing longitudinal change in knee cartilage volume measured from magnetic resonance imaging in healthy men

OBJECTIVE

To determine whether the amount of joint cartilage in healthy, middle aged men is stable or changes over time, and what factors may influence this.

METHODS

In a cohort study, 28 healthy men (70% of the original cohort; mean (SD) age, 51.9 (12.8) years) had baseline knee magnetic resonance imaging (MRI) of their dominant knee and repeat MRI of the same knee approximately 2.0 years later. Knee cartilage volume was measured at baseline and follow up. Risk factors assessed at baseline, including sex hormones and metabolic bone markers, were tested for their association with change in knee cartilage volume over time.

RESULTS

Mean (SD) reduction in tibial cartilage volume per year was 162 (93) microl. This represented a 2.8% reduction in total tibial articular cartilage per year (95% confidence interval, 0.2% to 5.5%). Tibial cartilage loss was associated with serum free testosterone level, independently of age, body mass index, baseline tibial cartilage volume tibial plateau area, and total bone mineral content. Overall, testosterone accounted for 14.5% (partial r2) of the variation in change in tibial cartilage volume. There was a trend towards a positive association between tibial cartilage loss and urinary N-telopeptide cross-links of type I collagen (Ntx) (p = 0.057).

CONCLUSIONS

Further studies will be required to determine whether hormonal manipulation or treatment with antiresorptive drugs will reduce the risk of knee osteoarthritis in men in later life.

Genital skin fibroblasts (GF) of patients with androgen insensitivity syndrome express higher insulin-like growth factor binding protein (IGFBP)-2, -3 and -5 than GF of normally virilized males

BACKGROUND

We investigated the effects of androgens, estradiol (E2) and insulin-like growth factor (IGF)-I on IGF-II, insulin-like growth factor binding protein (IGFBP)-2, -3 and -5 and mRNA in genital fibroblasts (GF) from patients with complete androgen insensitivity (CAIS) and normally virilized males (C).

METHODS

Proteins were measured by specific RIA and Western ligand blot, and specific mRNA levels by RT-PCR normalized by GAPDH levels.

RESULTS

Secretion of IGF-II was lowered in CAIS (p<0.001) GF and by testosterone + IGF-I in C GF. Secretion of IGFBP-2 was higher (p<0.001) in CAIS GF and IGFBP-2 mRNA levels were increased by E2 in C GF (p<0.05). E2 stimulated IGFBP-2, -3 and -5 expression in CAIS GF. CAIS GF also secreted more IGFBP-3 (p<0.001) and accumulated 3-5 times more IGFBP-5 mRNA than C GF (p<0.001).

CONCLUSION

In contrast to C GF, the availability of IGF-II in CAIS GF is apparently decreased by two facts: by the decreased expression and by increased expression of IGFBP-2, -3 and -5. Furthermore, E2 and IGF-I modulate the expression of IGF-II and IGFBP in GF. This may play a role in the failure to develop male external genitals in CAIS patients.

Dual effects of 17beta-oestradiol on interleukin 1beta-induced proteoglycan degradation in chondrocytes

OBJECTIVE

To determine whether 17beta-oestradiol (E2) modulates interleukin (IL) 1beta-induced proteoglycan degradation in chondrocytes, and to analyse the part played by metalloproteinases (MMPs) in this process.

METHODS

Primary cultured rabbit articular chondrocytes were prepared and treated with 10 ng/ml IL1beta combined or not with 0.1-10 nM E2. Neosynthesised proteoglycans (PGs) were evaluated after incorporation of [(35)SO(4)]sulphate and further analysed after chromatography on a Sepharose 2B column. Chondrocyte mRNA levels of aggrecan, MMP-1, -3, -13, and tissue inhibitor of metalloproteinase-1 (TIMP-1) were studied by northern blot. MMP-1 activity was measured by zymography. MMP-1 gene transcription was studied by transient transfection of chondrocytes with an MMP-1-luciferase construct.

RESULTS

E2 modulated the IL1beta-induced total sulphated PGs in rabbit articular chondrocytes, which decreased as the E2 concentration was increased. At a low concentration (0.1 nmol/l) E2 counteracts the IL1beta-induced decrease in sulphated PG, while at high concentration (10 nmol/l) E2 enhances the IL1beta effects. A biphasic E2 effect was also observed on IL1beta-induced disaggregation of PG, 53-58 kDa gelatinolytic activity, and MMP-1, -3, and -13 mRNA levels. In contrast, E2 did not modify the level of aggrecan mRNA and had no effect on TIMP-1 mRNA expression. Finally, simultaneous addition of IL1beta and E2 (0.1-10 nmol/l) did not modify IL1beta-induced MMP-1-luciferase activity, suggesting that E2 effects probably occur at the post-transcriptional level of MMP gene expression.

CONCLUSION

Oestrogen concentration may have an inverse effect on IL1beta stimulated proteoglycan degradation and MMP production by chondrocytes.

Effects of long-term estrogen replacement therapy on articular cartilage IGFBP-2, IGFBP-3, collagen and proteoglycan levels in ovariectomized cynomolgus monkeys

OBJECTIVE

The purpose of this study was to determine the effects of long-term estrogen replacement therapy (ERT) on insulin-like growth factor binding protein (IGFBP)-2, IGFBP-3, collagen and proteoglycan levels in the articular cartilage of the knee joint in a well-characterized monkey model of naturally occurring osteoarthritis (OA). A secondary aim was to evaluate the effect of soy phytoestrogen treatment on these articular cartilage components.

DESIGN

Monkeys were ovariectomized and given ERT, soy phytoestrogen treatment or no treatment (control) for 3 years. Ten animals were randomly selected from each of the three groups and the cartilage was dissected from the proximal tibia and distal femur of the knee. Levels of IGFBP-2, IGFBP-3, and total protein were measured in cartilage desorptions, and proteoglycan levels and collagen levels were measured in the cartilage tissue. Sections from the tibial plateau of the opposite knee were immunostained using antibodies directed against IGFBPs and evaluated subjectively.

RESULTS

IGFBP-3 levels were significantly higher, and total protein levels were significantly lower in the cartilage desorption samples from the estrogen-treated animals compared to the control animals. There were no significant differences in IGFBP-2, collagen or proteoglycan levels between the estrogen-treated and control groups. Soy phytoestrogen treatment had no significant effect on the levels of any of the cartilage components that were measured. The staining patterns observed by immunohistochemistry suggested local production of IGFBP-2 and IGFBP-3 by articular cartilage chondrocytes.

CONCLUSIONS

Long-term estrogen treatment results in increased IGFBP-3 levels in articular cartilage without a significant change in IGFBP-2, collagen or proteoglycan content, and IGFBP-3 appears to be synthesized by articular cartilage chondrocytes. Long-term soy phytoestrogen treatment did not have a statistically significant effect on the levels of IGFBP-2, IGFBP-3, collagen or proteoglycan.

Effect of estrogen on the expression of matrix metalloproteinase (MMP)-1, MMP-3, and MMP-13 and tissue inhibitor of metalloproternase-1 in osteoarthritis chondrocytes

The aim of this study was to evaluate the effect of estrogen on matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, and tissue inhibitor of metalloproteinase (TIMP)-1 in osteoarthritic chondrocytes. Chondrocytes from the knee cartilage of 25 postmenopausal osteoarthritic (OA) patients were cultured under various conditions: 0 pg/mL, 50 pg/mL, 500 pg/mL, and 5,000 pg/mL of 17beta-estradiol, with or without 10-1,000 pg/mL of either interleukin (IL)-1beta or tumor necrosis factor alpha (TNFalpha). MMP-1, MMP-3, MMP-13, and TIMP-1 in the conditioned media were analyzed with immunoblot or enzyme-linked immunosorbent assay (ELISA). Type II collagenolytic activity was measured by fluorogenic type II collagenolytic activity assay. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) using SYBR Green I dye was performed for the quantification of mRNA. Without cytokine stimulation, the secretion of MMP-1 was significantly reduced by 50 pg/mL of 17beta-estradiol (in immunoblot by a median of 12.3%, P=0.007; in ELISA by a median of 18.4%, P=0.001), and 500 pg/mL (in immunoblot by a median of 23.1%, P=0.001; in ELISA by a median of 21.0%, P=0.001). Additionally, under 10 pg/mL TNFalpha, 17beta-estradiol also significantly suppressed the secretion of MMP-1 (in immunoblot by a median of 39.0%, P=0.016; in ELISA by a median of 38.4%, P=0.041). Estrogen did not exert any significant effect on MMP-3, MMP-13, or TIMP-1 expression. With IL-1beta or TNFalpha above 10 pg/mL stimulation, 17beta-estradiol demonstrated no effect on MMP-1, MMP-3, MMP-13, or TIMP-1 secretion. Type II collagenolytic activity in the 50 pg/mL estradiol group decreased by 9.6% (-51.5-5.5%, P>0.05). 17beta-estradiol showed a tendency to decrease in MMP-1 mRNA. Estrogen may improve the imbalance between the amounts of MMPs and TIMP in chondrocytes, and these results suggest that hormone replacement therapy may provide some chondroprotective effect.

Estrogens, cartilage, and osteoarthritis

A role for estrogens in osteoarthritis is consistent with the larger increases in women than in men in the incidence and prevalence of hip, knee, and finger osteoarthritis after 50 years of age. Furthermore, hormone replacement therapy for the menopause seems to be associated with a decrease in the prevalence of symptoms and radiological alterations related to hip and knee osteoarthritis. The two estrogen receptors alpha and beta (ERalpha and Erbeta) have been identified in normal and osteoarthritic cartilage, indicating that cartilage can respond to estrogens. Finally, in vivo experiments in animals and in vitro studies have shed light on the mechanisms by which estrogens may influence chondrocyte metabolism.

Estrogen receptor alpha gene haplotype is associated with radiographic osteoarthritis of the knee in elderly men and women

OBJECTIVE

Genetic influences have been shown to play an important role in the etiology of osteoarthritis (OA), but the genes involved are ill-defined. We studied the association between polymorphisms in the estrogen receptor alpha (ERalpha) gene and the prevalence of radiographic OA of the knee.

METHODS

The study group comprised 1,483 men and women from the Rotterdam Study. Direct molecular haplotyping was used to determine the relationship between 2 polymorphisms in the ERalpha gene (the Pvu II and Xba I restriction fragment-length polymorphisms). Radiographs of the knee were evaluated according to the Kellgren/Lawrence (K/L) score, along with separate scores for osteophytosis and joint space narrowing.

RESULTS

Three different haplotype alleles were identified: px (54%), PX (34%), and Px (12%). Allele PX was associated with an increased prevalence of radiographic knee OA (K/L score >/=2). The prevalence of radiographic OA was 22% among subjects without allele PX, 24% among those carrying 1 copy, and 35% among subjects carrying 2 copies. The corresponding odds ratios, after adjustment for confounding factors, were 1.3 (95% confidence interval [95% CI] 0.9-1.7) for heterozygotes and 2.2 (95% CI 1.5-3.4) for homozygotes. Separate analyses for men and women showed similar risk estimates. The association appeared to be driven by osteophytosis and is somewhat consistent with the association observed in previous studies of these polymorphisms in relation to OA.

CONCLUSION

This study shows that polymorphisms in the ERalpha gene are associated with radiographic OA of the knee, and in particular with osteophytosis, in both elderly men and elderly women.

Is there any rationale for prescribing hormone replacement therapy (HRT) to prevent or to treat osteoarthritis?

BACKGROUND

During the last two decades of the 20th century, hormone replacement therapy (HRT) has been considered as the sole pharmacological approach for counterbalancing or mitigating the effects of estrogens deprivation in post-menopausal women. Subsequently, HRT has been widely recommended for the management of chronic diseases occurring, in women during the second half of their life. The overall risk/benefit ratio of estrogens has been recently reassessed in the light of long-term prospective studies failing to demonstrate the expected benefit of HRT on cardiovascular diseases incidence. Osteoarthritis (OA) is one of the chronic conditions for which HRT has been suggested to provide beneficial outcomes.

RESULTS

The presence of estrogen receptors in human cartilage is no longer debated. However, cellular or animal models of OA do not provide an unequivocal pathway for the influence of gonadal steroids on cartilage. Similarly, studies attempting to correlate serum or urinary levels of sex steroids to the onset or progression of OA gave conflicting results. No randomized, prospective, controlled trial was designed to specifically assess the impact of hormone replacement therapy on symptomatic or structural progression of OA. Large-scale observational studies or trials designed to assess other potential benefits of estrogens suggest that HRT use does not provide symptomatic relief in OA but may interfere with its long-term structural progression, particularly in the lower limbs.

CONCLUSION

Based on the recent results of the Women Health Initiative suggesting that HRT health risks may outweigh benefits, one can hardly recommend, with the current level of evidence, HRT as a first-line treatment against progression of OA.

Effects of long-term estrogen replacement therapy on osteoarthritis severity in cynomolgus monkeys

OBJECTIVE

To determine the effects of long-term estrogen replacement therapy (ERT) on the severity of osteoarthritis (OA) of the knee joint in surgically postmenopausal (bilaterally ovariectomized) female monkeys. A secondary aim was to evaluate the effect of soy phytoestrogen (SPE) treatment on the severity of OA.

METHODS

Feral adult female cynomolgus macaques were ovariectomized bilaterally and then randomly divided into 3 age- and weight-matched treatment groups. For 3 years, the first group received ERT with conjugated equine estrogens, the second group received SPE, and the third group received no treatment (controls). At necropsy, histologic lesions of OA were graded, and the area and thickness of cartilage and subchondral bone were measured. The data were summarized by principal components analysis, and the resulting factors and individual variables were compared using analysis of variance and analysis of covariance (age and weight as covariates).

RESULTS

Cartilage lesions of OA were significantly less severe in the animals given ERT compared with those in the control group. This treatment effect remained significant when adjusted for age and weight. The factor representing subchondral bone was significantly higher, but the number of osteophytes was lower, in the ERT group compared with the control group. SPE treatment had no significant effect on cartilage or bone lesions of OA.

CONCLUSION

These results demonstrate that long-term ERT significantly reduces the severity of OA lesions in this animal model.

Lessons from animal models of osteoarthritis

Characterization of transgenic murine osteoarthritis (OA) models and analysis of anterior cruciate ligament and meniscectomy models in various species, including rodents, has provided insight into pathogenic mechanisms and impact of loading. Development of a transgenic murine OA model by postnatal expression in hyaline cartilage of constitutively expressed human matrix metalloproteinase-13 emphasizes the potential role of this enzyme. On the other hand, collagenase involvement in OA models seems a confined focal process, complicating therapeutic approaches. The potential role of interleukin-1 still needs further confirmation. Apart from destructive cytokines, disturbed growth factor responses seems obvious. Transforming growth factor-beta is a crucial mediator in osteophyte formation, but its role in cartilage destruction has not yet been clarified. Nitric oxide appears involved in chondrocyte apoptosis and blocking of nitric oxide provides protection against joint pathology in OA models. Treatment with a range of disease-modifying drugs showed some efficacy in a number of OA models, but its predictive value for human OA remains obscure.

Users of oestrogen replacement therapy have more knee cartilage than non-users

BACKGROUND

Osteoarthritis (OA) is increasingly prevalent in the years after menopause. Epidemiological data suggest that the use of oestrogen replacement therapy (ERT) may protect against knee OA.

AIM

To test the hypothesis that long term ERT (longer than five years) is associated with increased knee cartilage in postmenopausal women.

METHODS

The study involved 81 women (42 current users (> or = five years) of ERT and 39 who had never used it). Articular cartilage volumes were determined by processing images acquired in the sagittal plane using a T1 weighted fat suppressed magnetic resonance sequence on an independent work station.

RESULTS

After bone size had been accounted for, ERT users had higher tibial cartilage volume than non-users. Total tibial cartilage volume was 7.7% (0.23 ml) greater in the group of ERT users (2.98 (0.47) ml; mean (SD)) than in the untreated group (2.75 (0.50) ml). The difference, after adjustment for the significant explanatory factors (years since menopause, body mass index, age at menopause, and smoking), between the ERT users and non-users increased from 0.23 ml to 0.30 ml (95% confidence interval 0.08 to 0.52, p=0.008). These differences persisted after exclusion of women with OA.

CONCLUSIONS

After adjustment for multiple confounders, women using long term ERT have more knee cartilage than controls. This may indicate that ERT prevents loss of knee articular cartilage.

Aging and the etiopathogenesis and treatment of osteoarthritis

Knee OA in the older adult is often the result of multiple factors, some of which are intrinsic to the joint tissues and related to aging and others, such as obesity, which are extrinsic and influence the rate of development and severity of the disease. Obesity and quadricep weakness are factors that may be modifiable. The focus in managing patients with knee OA should not only be centered on the improvement of pain but also improvement in function. A combination of simple analgesics and nonpharmacologic measures, including exercises to strengthen the knee extensors, should be employed. Patients also can benefit from aerobic exercises, such as a walking or swimming program and strategies for joint protection. When medications are needed, the least toxic drugs possible should be used given the increased susceptibility of older adults to unwanted side effects.

Menopause, oestrogens and arthritis

The menopause coincides with the appearance of many of the common arthritic conditions and with the lessening of severity of others such as SLE. The hormonal changes that occur may modulate these diseases. Thus, hormonal manipulation may have either beneficial or detrimental effects on the incidence and activity of a number of common joint diseases. We review the evidence regarding the effect of the menopause and oestrogen replacement therapy on the pathogenesis, incidence and prevalence and disease activity of osteoarthritis, rheumatoid arthritis, systemic lupus erythematosus and carpal tunnel syndrome.