Androgens and ankylosing spondylitis: a role in the pathogenesis?

Biomechanics in the onset and severity of spondyloarthritis: a force to be reckoned with

Increasing evidence suggests that there is a pivotal role for physical force (mechanotransduction) in the initiation and/or the perpetuation of spondyloarthritis; the review contained herein examines that evidence. Furthermore, we know that damage and inflammation can limit spinal mobility, but is there a cycle created by altered spinal mobility leading to additional damage and inflammation?Over the past several years, mechanotransduction, the mechanism by which mechanical perturbation influences gene expression and cellular behaviour, has recently gained popularity because of emerging data from both animal models and human studies of the pathogenesis of ankylosing spondylitis (AS). In this review, we provide evidence towards an appreciation of the unsolved paradigm of how biomechanical forces may play a role in the initiation and propagation of AS.

Revealing mechanism of Methazolamide for treatment of ankylosing spondylitis based on network pharmacology and GSEA

Methazolamide is a carbonic anhydrase (CA) inhibitor with satisfactory safety. Our previous studies have demonstrated the elevation of CA1 expression and the therapeutic effect of Methazolamide in Ankylosing spondylitis (AS). In this study, we explored the pathogenic role of CA1 and the pharmacological mechanism of Methazolamide in AS through Gene Set Enrichment Analysis (GSEA) and network pharmacology. Seven out of twelve CA1 related gene sets were enriched in AS group. CA1 was core enriched in above seven gene sets involving zinc ion binding, arylesterase activity and one carbon metabolic process. Functional analysis of the candidate target genes obtained from the intersection of AS associated genes and Methazolamide target genes indicated that Methazolamide exerts therapeutic effects on AS mainly through inflammatory pathways which regulate the production of tumor necrosis factor, IL-6 and nitric oxide. PTGS2, ESR1, GSK3β, JAK2, NOS2 and CA1 were selected as therapeutic targets of Methazolamide in AS. Molecular docking and molecular dynamics simulations were performed successfully. In addition, we innovatively obtained the intersection of Gene Ontology (GO)/Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses and GSEA results, and found that 18 GO terms and 5 KEGG terms were indicated in the pharmacological mechanism of Methazolamide in AS, involving bone mineralization, angiogenesis, inflammation, and chemokine signaling pathways. Nevertheless, validation for these mechanisms is needed in vivo/vitro experiments.

No increased risk of alopecia in ankylosing spondylitis patients: A population-based cohort study in Taiwan

AIM

To investigate the association between ankylosing spondylitis (AS) and alopecia.

METHODS

In this cohort study, data from over 1 000 000 patients in the Taiwan Longitudinal Health Insurance Database were extracted. We selected newly diagnosed (outpatient department visit three or more times or admission at least once) patients with AS (ICD-9-CM = 720.0) from 2000 to 2012. For the non-AS comparison group, patients never diagnosed with AS were chosen from 1999 to 2013. In all, 3640 AS patients and 14 560 non-AS controls were selected. Cox proportional hazard model and Kaplan-Meier analysis were used to present the results. The adjusted hazard ratio (HR) in the Cox proportional hazard model was adjusted for age, sex, hypertension, hyperlipidemia, diabetes, atopic dermatitis, and mental disorder.

RESULTS

No increased risk of alopecia in AS patients was shown in the Cox proportional hazard model (crude HR 1.16, P = 0.595; adjusted HR 1.16, P = 0.599). Negative results are found as well in subgroup analysis of different age, sex (age 20-40 y: HR 1.03, P = 0.925; Age ≥40 y: HR 1.49, P = 0.406; Female: HR 1.17, P = 0.759; Male: HR 1.15, P = 0.667), and phenotypes of alopecia (androgenetic alopecia: HR 1.19, 95% confidence interval [CI] 0.58-2.41; alopecia areata: HR 0.98, 95% CI 0.37-2.62). A significant positive correlation is found between atopic dermatitis and alopecia (adjusted HR 8.05, P = 0.039).

CONCLUSION

In this population-based cohort study, we found no association of risk of alopecia and AS.

A Pooled Analysis Reporting the Efficacy and Safety of Secukinumab in Male and Female Patients with Ankylosing Spondylitis

Introduction

Despite of higher disease burden, lower efficacy to biologics has been reported in female compared to male patients with ankylosing spondylitis (AS). The aim of this study was to evaluate the efficacy and safety of secukinumab by sex in patients with active AS from five phase 3 studies (MEASURE 1–5) through 52 weeks.

Methods

Baseline demographics, disease characteristics and efficacy outcomes at Weeks 16 and 52 were summarized for males versus females. Baseline predictor analysis used multivariable logistic regression for binary outcome measures or generalized linear model for continuous outcome measures to assess the impact of sex as one of the independent variables on selected efficacy outcomes at Week 52.

Results

Overall, 1031 males and 396 females were included in this analysis. Smoking status, hs-CRP, prior exposure to TNF inhibitors, BASMI occiput-to-wall and tragus-to-wall distance (cm) were higher in males, whereas MASES was higher in females. Efficacy outcomes i.e., ASAS40 responses and BASDAI change from baseline at Weeks 16 and 52 were generally comparable between males and females. Response rates were found to be significantly higher in male patients when compared with female patients only for ASDAS-CRP inactive disease (ID) at Week 52.

Conclusion

Comparable efficacy and safety outcomes were observed between male and female patients with active AS treated with secukinumab over 52 weeks. Further, sex was not an independent predictor of treatment response to secukinumab as assessed by ASAS40 responder rates and BASDAI change from baseline; association of ASDAS-CRP ID responder rates with sex warrants further exploration.

Trial registration

ClinicalTrials.gov; NCT01358175, NCT01649375, NCT02008916, NCT02159053, and NCT02896127.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40744-021-00380-2.

The Effects of Sex and Estrogen on Radiographic Progression of Ankylosing Spondylitis in Korean Patients

Objective

Ankylosing spondylitis (AS) is a chronic inflammatory disease with obvious male preponderance Males show more severe radiographic manifestations compared with females This study aimed to evaluate the effects of sex and estrogen on the radiographic progression of AS.

Methods

A total of 101 patients with AS were included in this study All of the radiographs were scored using the modified Stoke AS Spine Score (mSASSS) Serum levels of 17β-estradiol (E2), dickkopf-1 (Dkk1), and leptin were detected by enzyme-linked immunosorbent assay The generalized estimating equations model was used to evaluate factors associated with spinal radiographic progression.

Results

The mean age at disease onset was 273±107 years, and 16 patients (158%) were female In the multivariable analysis, body mass index (β-coefficient=012; p=0047) and levels of Dkk1 (β-coefficient=-011; p<0001), and female (β-coefficient=-140; p=0001) were associated with radiographic progression Among male patients with AS, baseline C-reactive protein (β=011; p=0005) and mSASSS (β=021; p=0030) were also associated with radiographic progression E2 and leptin levels were not significantly related to the radiographic progression.

Conclusion

Although female patients were associated with less radiographic progression in AS, there was no significant relationship between serum estrogen level and radiographic progression Results of current study suggests that genetic factors or other environmental factors associated with female may influence radiographic progression in patients with AS.

Baseline MRI inflammation is not a determinant of 5-year bone mineral density loss in patients with early spondyloarthritis

OBJECTIVE

The aim of this study was to assess the effect of baseline inflammation on Magnetic Resonance Imaging (MRI) on the change in Bone Mineral Density (BMD) over 5 years in patients with early spondyloarthritis (SpA).

METHODS

From the patients of the DESIR cohort (an early axial SpA cohort), patients with BMD data at both baseline and 5 years, and baseline spine and sacroiliac joints MRI were included. Inflammation was assessed with the SpondyloArthritis Research Consortium of Canada (SPARCC) spine score. Significant BMD loss was defined by a change of >0.03g/cm². No patients had received TNF blockers before inclusion in the cohort. Univariate and multivariable prognostic analyses were performed. An inverse propensity score weighting method was used to handle confounders.

RESULTS

One hundred and eighty-three patients were included (mean age 33.9±8.7 years, 58.5% men). A significant bone loss was reported in 51% (n=92) of patients at either lumbar spine or hip. Fourteen (7%) patients had low BMD (Z-score <-2) at the end of the follow-up vs. 28 (15%) at baseline. In multivariable analysis, age was a protective factor of 5 year-BMD loss at any site (OR=0.96, 95% CI [0.93-0.99]). Baseline MRI inflammation has no significant effect on BMD change at any site (OR=0.84, 95% CI [0.46-1.53]).

CONCLUSION

Half of patients with early SpA have a significant bone loss at either lumbar spine or hip over 5 years. Baseline MRI inflammation is not a determinant of this bone loss.

Gender Differences in Axial Spondyloarthritis: Women Are Not So Lucky

PURPOSE OF REVIEW

Ankylosing spondylitis (AS) was historically seen as a predominantly male disease. However, more recent data showed a more homogenous sex prevalence. Unfortunately, in many studies in axial spondyloarthritis (axSpA), the number of women included is low and the analyses are often not stratified for gender distribution. The purpose of this review is to aggregate the existing data on gender differences in axSpA in order to increase the awareness that female axSpA patients are still under-recognized.

RECENT FINDINGS

Several studies considering gender differences revealed that female axSpA patients had different disease manifestations due to different immunological, hormonal, and genetic responses. For instance, allelic frequencies of the AHNK-gene and tissue non-specific alkaline phosphatase (TNAP) haplotypes differed between men and women with ankylosing spondylitis (AS). In addition, different levels of tumor necrosis factor (TNF), interleukins IL-6, IL-17, and IL-18, were found between the two sexes. Furthermore, female patients show a higher diagnostic delay compared to males. Several studies indicate a higher frequency of extra-articular manifestations (EAM) in female axSpA patients, such as enthesitis, psoriasis, and inflammatory bowel disease (IBD), whereas acute anterior uveitis is more prevalent in male patients. Male AS patients more frequently show a higher Bath Ankylosing Spondylitis Radiology Index (BASRI) scores and modified Stoke Ankylosing Spondylitis Spine Scores (mSASSS) than females, which indicates that males have higher radiological damage and radiographic progression. However, disease activity (BASDAI) and quality of life (AsQol) scores are significantly higher in women, and more importantly, they have significantly lower response rates to treatment with TNF inhibitors (TNFi) and a significantly lower drug adherence. Despite the fact that men with axial SpA have a worse radiologic prognosis, women have a high disease burden, in part because they have a longer delay in diagnosis, higher disease activity, and significantly less responsiveness to treatment with TNFi.

Estrogen attenuates the spondyloarthritis manifestations of the SKG arthritis model

Background

Ankylosing spondylitis (AS) is a male-predominant disease, and radiographic evidence of damage is also more severe in males. Estrogen modulates immune-related processes such as T cell differentiation and cytokine production. This study aimed to evaluate the effect of estrogen on the disease activity of spondyloarthritis (SpA).

Methods

The effects of estrogen on the development of arthritis were evaluated by performing ovariectomy and 17β-estradiol (E2) pellet implantation in zymosan-treated SKG mice. Clinical arthritis scores were measured, and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) small-animal positron emission tomography/computed tomography performed to quantify joint inflammation. The expression of inflammatory cytokines in joint tissue was measured.

Results

E2-treated mice showed remarkable suppression of arthritis clinically and little infiltration of inflammatory cells in the Achilles tendon and intervertebral disc. ¹⁸F-FDG uptake was significantly lower in E2-treated mice than in sham-operated (sham) and ovariectomized mice. Expression of TNF, interferon-γ, and IL-17A was significantly reduced in E2-treated mice, whereas expression of sclerostin and Dickkopf-1 was increased in E2-treated mice compared with sham and ovariectomized mice.

Conclusions

Estrogen suppressed arthritis development in SKG mice, a model of SpA. Results of this study suggest that estrogen has an anti-inflammatory effect on the spondyloarthritis manifestations of the SKG arthritis model.

Sex differences in autoimmune disease

Female/male ratios of autoimmune diseases range from 10: 1 to 1: 3, with similar severity between the sexes. Men and women respond similarly to the infection and to vaccination, arguing against intrinsic sex differences in immune response. In autoimmune-like illnesses caused by environmental agents sex discrepancy is explained by differences in exposure. Endogenous hormones could cause sex discrepancy if their effect is a threshold off-on switch rather than quantitatively variable. X-inactivation and imprinting could cause sex discrepancy. Other possibilities include chronobiologic differences and pregnancy and menstruation biologies in which men differ from women.

DCIR maintains bone homeostasis by regulating IFN-γ production in T cells

Dendritic cell immunoreceptor (DCIR) is a C-type lectin receptor mainly expressed in DCs. Dcir (-/-) mice spontaneously develop autoimmune enthesitis and ankylosis accompanied by fibrocartilage proliferation and ectopic ossification. However, the mechanisms of new bone/cartilage formation in Dcir (-/-) mice remain to be elucidated. In this study, we show that DCIR maintains bone homeostasis by regulating IFN-γ production under pathophysiological conditions. DCIR deficiency increased bone volume in femurs and caused aberrant ossification in joints, whereas these symptoms were abolished in Rag2(-/-)Dcir(-/-) mice. IFN-γ-producing T cells accumulated in lymph nodes and joints of Dcir(-/-) mice, and purified Dcir(-/-) DCs enhanced IFN-γ(+) T cell differentiation. The ankylotic changes and bone volume increase were suppressed in the absence of IFN-γ. Thus, IFN-γ is a positive chondrogenic and osteoblastogenic factor, and DCIR is a crucial regulator of bone metabolism; consequently, both factors are potential targets for therapies directed against bone metabolic diseases.

Somatosensory evoked potential findings in ankylosing spondylitis

OBJECTIVE

Somatosensory evoked potential (SSEP) abnormalities were reported in patients with ankylosing spondylitis (AS). This study aimed to investigate SSEP abnormalities and its relation with clinical findings in AS patients.

MATERIALS AND METHODS

The study included 26 patients with AS and 17 age-matched health volunteers (Control for SSEP). Median nerve SSEP findings were normal in all AS cases.

RESULTS

However, delayed latency and/or very low amplitude of tibial nerve SSEP was found in 20 (76.9%) AS patients. There were significant correlations between tibial SSEP latency and disease duration (R=0.433 to 0.635). There was also an inverse correlation between tibial SSEP amplitude and disease duration (R=-0.429, p=0.047). Serum estradiol level, hip total bone mineral density, The Bath Ankylosing Spondylitis Functional Index (BASFI) score and Beck depression score were significantly lower in AS patients with SSEP abnormalities (37.3±10.8 pg/mL, 0.916±0.123 g/cm(2), 35.0±27.9, 12.8±8.4, respectively) than in AS patients without SSEP abnormalities (53.7±12.3 pg/mL, 1.103±0.197 g/cm(2), 64.8±15.5, 24.8±10.1, respectively).

CONCLUSION

Significant inverse correlations between SSEP latencies and dehydroepiandrosterone sulphate (DHEAS) levels were found (R=-0.400 to -0.713). There were also significant inverse correlation between SSEP latencies and DHEAS/oestrogen index (R=-0.596 to -0.868), and between SSEP latencies and DHEAS/Progesterone index (R=-0.467 to -0.685). As a conclusion, this study indicates that tibial nerve SSEP abnormalities are common in patients with AS and there are significant correlations between clinical findings of AS and SSEP abnormalities.

Sex-dependent regulation of cytochrome P450 family members Cyp1a1, Cyp2e1, and Cyp7b1 by methylation of DNA

Sexual differences are only partially attributable to hormones. Cultured male or female cells, even from embryos before sexual differentiation, differ in gene expression and sensitivity to toxins, and these differences persist in isolated primary cells. Male and female cells from Swiss Webster CWF mice manifest sex-distinct patterns of DNA methylation for X-ist and for cytochrome P450 (CYP; family members 1a1, 2e1m, and 7b1. Dnmt3l is differentially expressed but not differentially methylated, and Gapdh is neither differentially methylated nor expressed. CYP family genes differ in expression in whole tissue homogenates and cell cultures, with female Cyp expression 2- to 355-fold higher and Dnmt3l 12- to 32-fold higher in males. DNA methylation in the promoters of these genes is sex dimorphic; reducing methylation differences reduces to 1- to 6-fold differences in the expression of these genes. Stress or estradiol alters both methylation and gene expression. We conclude that different methylation patterns partially explain the sex-based differences in expression of CYP family members and X-ist, which potentially leads to inborn differences between males and females and their different responses to chronic and acute changes. Sex-differential methylation may have medical effects.

Bone oedema on MRI is highly associated with low bone mineral density in patients with early inflammatory back pain: results from the DESIR cohort

OBJECTIVES

To assess bone mineral density (BMD) at lumbar spine and hip in a large cohort of patients with early inflammatory back pain (IBP) suggestive of axial spondyloarthritis (SpA), and to assess systemic and bone inflammation (according to MRI) as risk factors of low BMD.

PATIENTS AND METHODS

332 (52.4% male) patients with IBP suggestive of axial SpA defined by Calin or Berlin criteria were recruited; they had lumbar spine and hip BMD and body composition measurements. Low BMD was defined by Z≤-2 (at least one site). Clinical, biological (erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)) and imaging (x-rays, spine and sacroiliac joint MRI) parameters were compared in patients with and without low BMD (Z≤-2). Significant parameters in univariate analysis were tested in multivariate models.

RESULTS

Patients (mean age 33.8 years) had a short duration of axial symptoms (mean 1.6 years); 71.4% fulfilled the Assessment of Spondyloarthritis International Society criteria for axial SpA and HLA-B27 was present in 62.1%. 43 (13.0%) had low BMD (88% male). Multivariate logistic regression showed that parameters significantly associated with low BMD (any site) were the presence of bone marrow oedema (inflammatory lesions) on MRI (OR 4.63, p=0.001), either ESR or CRP (OR 2.60, p=0.037) and male gender (OR 9.60, p=0.0004).

CONCLUSIONS

This study conducted in a large cohort of young adults with early IBP suggestive of SpA shows that 13.0% of patients have a low BMD and that the main risk factor associated with low BMD was inflammation on MRI.

Androgen receptor genetic variants in male patients with ankylosing spondylitis in Taiwan

AIM

Ankylosing spondylitis (AS) is a chronic rheumatic disorder with gender differences. The aim of study was to investigate the association between polymorphisms of the androgen receptor (AR) gene and the susceptibility to AS in Taiwanese men of Han Chinese descent.

METHODS

We conducted a case-control study with 92 male AS patients and 108 healthy controls. Trinucleotide (CAG and GGC) repeats and seven single nucleotide polymorphisms (SNPs) rs962458, rs6152, rs1204038, rs5918757, rs2361634, rs6624304 and rs1337080 in the AR gene were genotyped.

RESULTS

We found that only one patient had polymorphic SNPs of the AR gene. None of the genotyped SNPs in the AR gene, originally found in Caucasians, was polymorphic in the Taiwanese men. Neither CAG nor GGC repeat lengths in the AR gene had a significant relationship with human leukocyte antigen (HLA)-B27 positivity or disease severity in AS.

CONCLUSION

There were no differences in CAG and GGC lengths in the AR gene between AS and the controls. None of the genotyped SNPs in AR gene are detected to be polymorphic in male Taiwanese, which indicates that the effect of AR gene on AS may be ethnic-specific and may be conserved in East Asians compared to Caucasian populations. Still, additional studies using large sets of subjects deserve further attention, since our sample size was small with limited statistical power and supporting evidence for association between the AR gene and AS risk in the Japanese population exists.

Gender differences in stress response: Role of developmental and biological determinants

Stress response is associated with manifestations of various psychosomatic and psychiatric disorders. Hence, it is important to understand the underlying mechanisms that influence this association. Moreover, men and women tend to react differently with stress-both psychologically and biologically. These differences also need to be studied in order to have a better understanding in the gender difference observed for many disorders, which are likely to be contributed by the gender difference in stress reactivity and responses. Such an understanding would have a significant impact on our understanding about how adult health is set during early life and how adult disease could be prevented in men and women.

Low bone mineral density is related to male gender and decreased functional capacity in early spondylarthropathies

The objective of this study was to determine the prevalence and risk factors of low bone mineral density (BMD) in patients with spondylarthropathies (SpA) at an early stage of disease. In this cross-sectional study, the BMD of lumbar spine and hips was measured in 130 consecutive early SpA patients. The outcome measure BMD was defined as (1) osteoporosis, (2) osteopenia, and (3) normal bone density. Logistic regression analyses were used to investigate relations between the following variables: age, gender, disease duration, diagnosis, HLA-B27, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), Bath Ankylosing Spondylitis Metrology Index (BASMI), extra-spinal manifestations and medication, with outcome measure low BMD (osteopenia and/or osteoporosis). The SpA population had a median time since diagnosis of 6.6 months and a disease duration of 6.3 years. In total, 9% of the early SpA patients had osteoporosis, 38% osteopenia, and 53% normal BMD. On univariate analyses, male gender, diagnosis of ankylosing spondylitis, increased CRP, high BASFI, and high BASMI were significantly associated with low BMD. Factors showing a relation with low BMD in the multivariate model were male gender (OR 4.18, 95% confidence interval (CI) 1.73–10.09), high BASMI (OR 1.54, 95% CI 1.14–2.07), and high BASFI (OR 1.18, 95% CI 1.00–1.39). In early SpA patients, a high frequency (47%) of low BMD in femur as well as in lumbar spine was found. Low BMD was associated with male gender and decreased functional capacity. These findings emphasize the need for more alertness for osteoporosis and osteopenia in spondylarthropathy patients at an early stage of the disease.

Pattern of ankylosing spondylitis in an Iranian population of 98 patients

The prevalence and pattern of ankylosing spondylitis (AS) can vary from country to country, according to genetic and environmental factors. This study aims to analyze the patterns of disease in a population of Iranian patients with AS. We performed a prospective study (2002-2007) analyzing 98 patients with diagnosis of AS according to the modified New York criteria. Selected patients underwent complete clinical (initial symptom, axial and peripheral involvement, heel enthesitis, extra-articular manifestations) and radiological (sacroiliac, lumbar, thoracic, and cervical spine) investigations, and these data were compared with sex, age at onset, and HLA-B27. There was predominance of men (71.4%), adult onset (>16 years, 90.8%), and positive HLA-B27 (73.4%). Family history of AS was noted in 14.3% of the patients. The predominant initial symptoms were inflammatory low back pain (44.2%). Radiological findings included syndesmophytes in 34.7% and "bamboo spine" in 16.3% of patients. Acute anterior uveitis was noted in 44.9% of patients. Male sex was associated with involvement of shoulder (P = 0.001). Female sex and juvenile-onset AS were associated with extra-articular involvement. Positive HLA-B27 was associated with hip involvement (P = 0.042) and adult-onset AS (P = 0.035). Analysis of the patterns of disease in this population of 98 southern Iranian patients with AS revealed that female sex and juvenile-onset AS were associated with extensive extra-axial involvement; and HLA-B27 was associated with hip involvement.

Sex differences in autoimmune disease

Many, but not all, autoimmune diseases primarily affect women. In humans, severity of illness does not differ between men and women. Men and women respond similarly to infection and vaccination, which suggests that the intrinsic differences in immune response between the sexes do not account for differences in disease frequency. In autoimmune-like illnesses caused by recognized environmental agents, sex discrepancy is usually explained by differences in exposure. Endogenous hormones are not a likely explanation for sex discrepancy; hormones could have an effect if the effect is a threshold rather than quantitative. X and Y chromosomal differences have not been studied in depth. Other possibilities to explain sex discrepancy include chronobiologic difference and various other biologies, such and pregnancy and menstruation, in which men differ from women.

Sexual dimorphism, but not testosterone itself, is responsible for ankylosing enthesitis of the ankle in B10.BR (H-2k) male mice

BACKGROUND

Ankylosing enthesopathy (ANKENT) with progressive stiffening of ankle and tarsal joints of the hind limbs is a naturally occurring arthropathy in B10.BR mice. Some features are similar to those of the spondyloarthropathies in humans.

OBJECTIVE

To study the role of sexual dimorphism and testosterone in the development of ANKENT.

METHODS

The incidence of ANKENT was observed in non-castrated, castrated, and testosterone substituted castrated male mice, and in control and testosterone treated female mice.

RESULTS

ANKENT occurred only in males; it did not develop in males castrated at age 2-3 months but occurred in castrated males injected with testosterone. Females injected with testosterone did not develop ANKENT.

CONCLUSION

Testosterone can replace what castration eliminates, at least in the postpubertally castrated males, but is itself not sufficient to induce joint disease.

Bone loss in males with ankylosing spondylitis: its relation to sex hormone levels

OBJECTIVE

Osteoporosis is a common complication of ankylosing spondylitis (AS). The aim of the present study was to assess the association of sex hormone levels with bone loss in males with AS.

DESIGN

A cross-sectional study. Patients The study group consisted of 58 male patients with primary AS. The mean age was 38.2 years (range 18-59 years).

MEASUREMENTS

Bone mineral density (BMD) was measured in the left proximal femur. Serum FSH, LH, total testosterone (T), dehydroepiandrosterone sulfate (DHEAS), oestradiol (E2) and progesterone levels were measured.

RESULTS

Bone loss was observed in 54.5% of cases at the femoral neck and in 52.3% of cases at the trochanter and total hip. Bone loss was found in 40 (69%) cases in at least one of these three regions. Serum DHEAS was low in 12 (30.8%) of the cases with bone loss, and one (5.9%) of those without (P = 0.043). The ratio of serum T/DHEAS was higher in those with bone loss (5.24 +/- 3.70) than in those without (3.58 +/- 3.16) (P = 0.026).

CONCLUSIONS

The results showed that bone loss might be related to low serum DHEAS levels in males with AS.

Bone turnover markers, anterior pituitary and gonadal hormones, and bone mass evaluation using quantitative computed tomography in ankylosing spondylitis

The objective of this study was to determine bone mineral density (BMD) distribution in ankylosing spondylitis (AS) using quantitative computed tomography (QCT), to study bone turnover and anterior pituitary and gonadal hormonal axis in AS, and to look for correlations between BMD, bone remodeling markers and gonadal and anterior pituitary hormones. Forty-three male consecutive patients with AS were enrolled prospectively [mean (SD) age of 36.4 (11.3) years (range: 17-67) and mean disease duration of 6.8 (5.2) years (range: 0.4-19)]. Spine BMD was measured in all patients by QCT, and the results were compared to 29 male patients undergoing lumbar CT scan for sciatica. Bone turnover and anterior pituitary and gonadal axis were assessed in 29 patients, and the results were compared to 30 male healthy blood donors. The mean (SD) BMD was 127.7 mg/cm(3) (48.9) (range: 8.8-265.7) and 152.1 (25.3) (range: 34.2-190.4) in patients and controls, respectively (p = 0.018). Patients had lower serum levels of osteocalcin and higher levels of serum testosterone, luteinizing hormone (LH), and prolactin than controls with a significant statistical difference. There was a positive significant statistical correlation between BMD and chest expansion, Schober's test, C7-wall distance, and negative significant statistical correlation with age, disease duration, Bath Ankylosing Spondylitis Metrology Index (BASMI), Bath Ankylosing Spondylitis Radiology Index (BASRI), and serum prolactin. No correlation was observed between bone turnover parameters and AS symptomatic and structural severity indexes. BMD is lower with increasing age and late and severe disease. Decreased bone formation with normal resorption and increased levels of serum prolactin may be involved in its pathophysiology.

Osteoporosis and ankylosing spondylitis

Ankylosing spondylitis is a chronic inflammatory joint disease in which inflammation of the entheses gradually causes local ossification and ankylosis. Diffuse osteoporosis responsible for bone fragility is another feature established by recent data. The bone loss predominates at the spine and can cause vertebral fractures that are rare but nonnegligible sources of mortality and morbidity late in the course of the disease.

Hypothalamic-pituitary-adrenal axis function in ankylosing spondylitis

OBJECTIVE

To assess basal function and responsiveness of the hypothalamic-pituitary-adrenal (HPA) axis in patients with ankylosing spondylitis during dynamic testing.

METHODS

Insulin induced hypoglycaemia (IIH) (Actrapid HM 0.1 IU/kg, as intravenous bolus) was induced in 17 patients and 11 healthy controls matched for age, sex, and body mass index. Concentrations of glucose, adrenocorticotrophic hormone (ACTH), cortisol, insulin, dehydroepiandrosterone sulphate (DHEAS), 17alpha-hydroxyprogesterone, interleukin 6 (IL-6), and tumour necrosis factor alpha (TNFalpha) were determined in plasma.

RESULTS

Comparable basal cortisol levels were found in the two groups, with a trend to be lower in ankylosing spondylitis. In the ankylosing spondylitis group, there were higher concentrations of IL-6 (mean (SEM): 16.6 (2.8) pg/ml v 1.41 (0.66) pg/ml in controls; p<0.001) and TNFalpha (8.5 (1.74) pg/ml v 4.08 (0.42) pg/ml in controls; p<0.01). Glucose, insulin, ACTH, DHEAS, and 17alpha-hydroxyprogesterone did not differ significantly from control. The IIH test was carried out successfully in 11 of the 17 patients with ankylosing spondylitis, and the ACTH and cortisol responses were comparable with control. General linear modelling showed a different course of glycaemia (p = 0.041) in the ankylosing spondylitis patients who met the criteria for a successful IIH test compared with the controls.

CONCLUSIONS

The results suggest there is no difference in basal HPA axis activity and completely preserved responsiveness of the HPA axis in patients with ankylosing spondylitis. The interpretation of the different course of glycaemia during IIH in ankylosing spondylitis requires further investigation.

Impact of oral contraceptive use on glucocorticoid sensitivity of pro-inflammatory cytokine production after psychosocial stress

We previously reported that women using oral contraceptives (OC) show blunted free cortisol responses to psychosocial stress compared to medication-free women. Low cortisol responses to stress have been shown to be associated with increased susceptibilities to chronic inflammatory and autoimmune processes in animal models and certain human diseases.To address the question if the blunted free cortisol response of OC users may be compensated at the level of the target tissue, we measured hypothalamus-pituitary-adrenal (HPA) axis activation and glucocorticoid (GC) sensitivity of pro-inflammatory cytokine production after psychosocial stress in 14 women using OC and 11 women in the luteal phase of the menstrual cycle. All subjects were exposed to the psychosocial stress paradigm 'Trier Social Stress Test' (TSST). Free cortisol was measured repeatedly before and after stress. GC sensitivity was assessed by dexamethasone (DEX) inhibition of lipopolysaccharide (LPS) stimulated production of interleukin-6 (IL-6) in whole blood, immediately before, as well as 10 and 60 min after the stress test. As expected, the stress test induced significant increases in free cortisol in luteal phase women, while OC users showed blunted responses (F=3.31;p<0.05). GC sensitivity showed different response patterns; In luteal phase women a slight but not significant decrease was observed throughout the experiment. In contrast, women using OC showed a significant increase in GC sensitivity after stress (F=3.559;p<0.05). These results show, that an increase in GC sensitivity of pro-inflammatory cytokine production may at least in part compensate the low cortisol levels seen in OC users after stress. This could be one mechanism to protect women using OC medication from chronic inflammatory and autoimmune diseases.

Perspectives on the relationship of adrenal steroids to rheumatoid arthritis

An expanded model of RA is presented that incorporates cumulative multifactorial processes operating over a prolonged physiological phase prior to initial clinical manifestations. During this phase, progressive imbalances in the homeostasis of core neuroendocrine, immunological, and microvascular systems are believed to occur. Normal adrenal function plays an essential role in helping to maintain homeostasis of core systems in health. In RA, chronic adrenal hypocompetence is suspected to occur in a minority subset of females who have younger clinical onset and males who have associated low serum testosterone levels. Chronic, relative glucocorticoid insufficiency is believed to contribute to development of inflammatory manifestations in RA patients. Androgenic deficiencies, particularly of gonadal origin in males, may also contribute to RA, particularly its decreased anabolic features. Precise influences of hypocompetent adrenal steroid function on long-term modeling of the immunological compartment and control of microvascular activation processes are not well understood. These complex mechanisms need to be elucidated for better understanding of the physiopathogenesis of RA. Nevertheless, at a clinical level, sufficient data are currently available to endorse further controlled studies of early clinical onset patients and prospective investigations to determine more definitively the roles of adrenal (and gonadal) steroids in subsets of RA patients and unaffected susceptible persons in the population.

Invited review: sex ratio and rheumatic disease

Human illnesses affect men and women differently. In some cases (diseases of sex organs, diseases resulting from X or Y chromosome mutations), reasons for sex discrepancy are obvious, but in other cases no reason is apparent. Explanations for sex discrepancy of illness occur at different biological levels: molecular (e.g., imprinting, X-inactivation), cellular (sex-specific receptor activity), organ (endocrine influences), whole organism (size, age), and environmental-behavioral, including intrauterine influences. Autoimmunity represents a prototypical class of illness that has high female-to-male (F/M) ratios. Although the F/M ratios in autoimmune diseases are usually attributed to the influence of estrogenic hormones, evidence demonstrates that the attributed ratios are imprecise and that definitions and classifications of autoimmune diseases vary, rendering at least part of the counting imprecise. In addition, many studies on sex discrepancy of human disease fail to distinguish between disease incidence and disease severity. In April 2001, the Institute of Medicine of the National Academy of Sciences published Exploring the Biological Contributions to Human Health: Does Sex Matter? (Wizemann T and Pardue M-L, editors). This minireview summarizes the section of that report that concerns autoimmune and infectious disease. Some thyroid, rheumatic, and hepatic autoimmune diseases have high F/M ratios, whereas others have low. Those that have high ratios occur primarily in young adulthood. Gonadal hormones, if they play a role, likely do so through a threshold or permissive mechanism. Examples of sex differences that could be caused by environmental exposure, X inactivation, imprinting, X or Y chromosome genetic modulators, and intrauterine influences are presented as alternate, theoretical, and largely unexplored explanations for sex differences of incidence. The epidemiology of autoimmune diseases (young, female) suggests that an explanation for sex discrepancy of these illnesses lies in differential exposure, vulnerable periods, or thresholds. Biologists have an opportunity to inform medical scientists about sex differences that explain different attack rates in specific diseases, and physicians offer biologists experiments of nature to test theories of sex.

Sex differences in glucocorticoid sensitivity of proinflammatory cytokine production after psychosocial stress

OBJECTIVE

Men and women show marked differences in susceptibility to disorders related to the immune system. These gender differences have been proposed to be mediated by functional interactions of the hypothalamus-pituitary-adrenal (HPA) and hypothalamus-pituitary-gonadal (HPG) axes. A potential mechanism involved in this interaction is the glucocorticoid (GC) sensitivity of relevant target tissues for GC. Therefore, the aim of the study reported here was to investigate the impact of psychosocial stress and HPA axis activation on the GC sensitivity of proinflammatory cytokine production in men and women.

METHODS

A total of 45 healthy subjects were investigated. Eighteen women in the luteal phase of their menstrual cycle and 27 men were exposed to a psychosocial stress test (Trier Social Stress Test). Salivary free cortisol levels were measured repeatedly after exposure to the stressor. GC sensitivity was assessed in vitro by dexamethasone inhibition of lipopolysaccharide-stimulated production of interleukin-6 and tumor necrosis factor-alpha.

RESULTS

The stress test induced significant increases in salivary free cortisol with no significant differences between men and women. In contrast, GC sensitivity and lipopolysaccharide-stimulated cytokine production showed large gender differences. In men GC sensitivity was markedly increased 1 hour after stress, whereas GC sensitivity decreased significantly in women. Similarly, lipopolysaccharide-induced cytokine production decreased in response to stress in men but increased in women.

CONCLUSIONS

These results demonstrate that despite similar free cortisol responses of men and women (studied in the luteal phase) to psychosocial stress, gender may exert differential effects on the immune system by modulating GC sensitivity of proinflammatory cytokine production.

Upregulation of lymphocyte apoptosis as a strategy for preventing and treating autoimmune disorders: a role for whole-food vegan diets, fish oil and dopamine agonists

Induced apoptosis of autoreactive T-lymphocyte precursors in the thymus is crucial for the prevention of autoimmune disorders. IGF-I and prolactin, which are lymphocyte growth factors, may have the potential to suppress apoptosis in thymocytes and thus encourage autoimmunity; conversely, dietary fish oil rich in omega-3 fats appears to upregulate apoptosis in lymphocytes. Since whole-food vegan diets may downregulate systemic IGF-I activity, it is proposed that such a diet, in conjunction with fish oil supplementation and treatment with dopamine agonists capable of suppressing prolactin secretion, may have utility for treating and preventing autoimmune disorders. This prediction is consistent with the extreme rarity of autoimmune disorders among sub-Saharan black Africans as long as they followed their traditional quasi-vegan lifestyles, and with recent ecologic studies correlating risks for IDDM and for multiple sclerosis mortality with animal product and/or saturated fat consumption. Moreover, there is evidence that vegan or quasi-vegan diets are useful in the management of rheumatoid arthritis, multiple sclerosis, and possibly SLE. The dopamine agonist bromocryptine exerts anti-inflammatory effects in rodent models of autoimmunity, and there is preliminary evidence that this drug may be clinically useful in several human autoimmune diseases; better tolerated D2-specific agonists such as cabergoline may prove to be more practical for use in therapy. The moderate clinical utility of supplemental fish oil in rheumatoid arthritis and certain other autoimmune disorders is documented. It is not unlikely that extra-thymic anti-inflammatory effects contribute importantly to the clinical utility of vegan diets, bromocryptine, and fish oil in autoimmunity. The favorable impact of low latitude or high altitude on autoimmune risk may be mediated by superior vitamin D status, which is associated with decreased secretion of parathyroid hormone; there are theoretical grounds for suspecting that parathyroid hormone may inhibit apoptosis in thymocytes. Androgens appear to up-regulate thymocyte apoptosis, may be largely responsible for the relative protection from autoimmunity enjoyed by men, and merit further evaluation for the management of autoimmunity in women. It will probably prove more practical to prevent autoimmune disorders than to reverse them once established; a whole-food vegan diet, coupled with fish oil and vitamin D supplementation, may represent a practical strategy for achieving this prevention, while concurrently lowering risk for many other life-threatening 'Western' diseases.

Hyposecretion of the adrenal androgen dehydroepiandrosterone sulfate and its relation to clinical variables in inflammatory arthritis

Hypothalamic-pituitary-adrenal underactivity has been reported in rheumatoid arthritis (RA). This phenomenon has implications with regard to the pathogenesis and treatment of the disease. The present study was designed to evaluate the secretion of the adrenal androgen dehydroepiandrosterone sulfate (DHEAS) and its relation to clinical variables in RA, spondyloarthropathy (Spa), and undifferentiated inflammatory arthritis (UIA). Eighty-seven patients (38 with RA, 29 with Spa, and 20 with UIA) were studied, of whom 54 were women. Only 12 patients (14%) had taken glucocorticoids previously. Age-matched, healthy women (134) and men (149) served as controls. Fasting blood samples were taken for determination of the erythrocyte sedimentation rate (ESR), serum DHEAS and insulin, and plasma glucose. Insulin resistance was estimated by the homeostasis-model assessment (HOMAIR). DHEAS concentrations were significantly decreased in both women and men with inflammatory arthritis (IA) (P < 0.001). In 24 patients (28%), DHEAS levels were below the lower extreme ranges found for controls. Multiple intergroup comparisons revealed similarly decreased concentrations in each disease subset in both women and men. After the ESR, previous glucocorticoid usage, current treatment with nonsteroidal anti-inflammatory drugs, duration of disease and HOMAIR were controlled for, the differences in DHEAS levels between patients and controls were markedly attenuated in women (P = 0.050) and were no longer present in men (P = 0.133). We concluded that low DHEAS concentrations are commonly encountered in IA and, in women, this may not be fully explainable by disease-related parameters. The role of hypoadrenalism in the pathophysiology of IA deserves further elucidation. DHEA replacement may be indicated in many patients with IA, even in those not taking glucocorticoids.

Gonadal and adrenal sex steroids in ankylosing spondylitis

A role for sex steroids in the pathogenesis of AS is suggested by the male predominance, the peak age of onset in young adults, the increased number of first manifestations and flares after pregnancy, and the fact that sex steroids may modulate immune functions. There is a theoretic possibility that (normal levels of) androgens are indeed relevant in the male sex skew of AS. It has been reported that men with AS have higher than normal androgen levels; however, the evidence that serum testosterone levels are elevated in patients with AS is not robust. Elevated DHEAS and 17 alpha-hydroxyprogesterone levels have been reported in male AS patients; these may be secondary to inflammation and stress but may theoretically also be causally related to AS. These elevations might result from a partial late onset 11 beta- or 21-hydroxylase deficiency. Current data on sex steroid hormones provide no straightforward explanation for the male predominance in AS. It is fair to say that present data in patients with long-standing AS are too limited to suggest a role for androgens in the perpetuation of the disease, but a role in the initiation and the early stages of AS cannot be excluded. Such information can only be obtained from prospective studies. Cross-sectional studies cannot clearly distinguish causal relation from secondary disease effects, because blood sampling to test these hypotheses only takes place many years after the onset of disease. The impact of sex steroids on these features of AS is still unresolved. There is as yet no rationale for the use of medication that modifies sex steroid hormones in the management of AS. Alternative explanations for the higher male prevalence of AS may be found in the different chromosomal configuration and body composition of men and women.