Presence of estrogen-binding sites on macrophage-like synoviocytes and CD8+, CD29+, CD45RO+ T lymphocytes in normal and rheumatoid synovium

An overview of Betacoronaviruses-associated severe respiratory syndromes, focusing on sex-type-specific immune responses

Emerging beta-coronaviruses (β-CoVs), including Severe Acute Respiratory Syndrome CoV-1 (SARS-CoV-1), Middle East Respiratory Syndrome-CoV (MERS-CoV), and Severe Acute Respiratory Syndrome CoV-2 (SARS-CoV-2, the cause of COVID19) are responsible for acute respiratory illnesses in human. The epidemiological features of the SARS, MERS, and new COVID-19 have revealed sex-dependent variations in the infection, frequency, treatment, and fatality rates of these syndromes. Females are likely less susceptible to viral infections, perhaps due to their steroid hormone levels, the impact of X-linked genes, and the sex-based immune responses. Although mostly inactive, the X chromosome makes the female's immune system more robust. The extra immune-regulatory genes of the X chromosome are associated with lower levels of viral load and decreased infection rate. Moreover, a higher titer of the antibodies and their longer blood circulation half-life are involved in a more durable immune protection in females. The activation rate of the immune cells and the production of TLR7 and IFN are more prominent in females. Although the bi-allelic expression of the immune regulatory genes can sometimes lead to autoimmune reactions, the higher titer of TLR7 in females is further associated with a stronger anti-viral immune response. Considering these sex-related differences and the similarities between the SARS, MERS, and COVID-19, we will discuss them in immune responses against the β-CoVs-associated syndromes. We aim to provide information on sex-based disease susceptibility and response. A better understanding of the evasion strategies of pathogens and the host immune responses can provide worthful insights into immunotherapy, and vaccine development approaches.

Estrogen downregulates TAK1 expression in human fibroblast-like synoviocytes and in a rheumatoid arthritis model

Transforming growth factor β-activated kinase-1 (TAK1), a member of the mitogen-activated protein kinase family, plays a key role in the pathogenesis and progression of rheumatoid arthritis (RA). Estrogen has been previously reported to delay arthritis progression. However, the exact association between TAK1 and estrogen remains elusive. The present study demonstrated that TAK1 was upregulated in synoviocytes of patients with RA compared with patients with osteoarthritis and healthy controls. In addition, TAK1 was also expressed in cultured fibroblast-like synoviocytes (FLS), and its levels decreased significantly in 17β-estradiol (E2)-treated cells in a dose-dependent manner. Furthermore, administration of E2 significantly decreased TAK1 expression and attenuated the development of collagen-induced arthritis (CIA). Taken together, the findings of the present study suggested that E2 mediates a decrease of TAK1 in both FLS and CIA, which subsequently results in a suppression of the pathological process of CIA. Therefore, estrogen may serve as a potential therapeutic agent for the treatment of RA by targeting TAK1.

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.

The many facets of macrophages in rheumatoid arthritis

Macrophages are central to the pathophysiology of rheumatoid arthritis (RA). They constitute the main source of pro-inflammatory cytokines and chemokines such as TNF and IL-1β, they activate a wide range of immune and non-immune cells, and they secrete diverse tissue degrading enzymes driving chronic pro-inflammatory, tissue destructive and pain responses in RA. However, they can also produce anti-inflammatory cytokines such as IL-10, secrete inhibitors of tissue degrading enzymes and promote immunoregulatory and protective responses, suggesting the existence of macrophages with distinct and diverse functional activities. Although the underlying basis of this phenomenon has remained obscure for years, emerging evidence has now provided insight into the mechanisms and molecular processes involved. Here, we review current knowledge on the biology of macrophages in RA, and highlight recent literature on the heterogeneity, origins and ontogeny of macrophages as part of the mononuclear phagocyte system. We also discuss their plasticity in the context of the M1/M2 paradigm, and the emerging theme of metabolic rewiring as a major mechanism for programming macrophage functions and pro-inflammatory activities. This sheds light into the many facets of macrophages in RA, their molecular regulation and their translational potential for developing novel protective and therapeutic strategies in the clinic.

Polymorphisms at phase I-metabolizing enzyme and hormone receptor loci influence the response to anti-TNF therapy in rheumatoid arthritis patients

The aim of this case-control study was to evaluate whether 47 single-nucleotide polymorphisms (SNPs) in steroid hormone-related genes are associated with the risk of RA and anti-TNF drug response. We conducted a case-control study in 3 European populations including 2936 RA patients and 2197 healthy controls. Of those, a total of 1985 RA patients were treated with anti-TNF blockers. The association of potentially interesting markers in the discovery population was validated through meta-analysis with data from DREAM and DANBIO registries. Although none of the selected variants had a relevant role in modulating RA risk, the meta-analysis of the linear regression data with those from the DREAM and DANBIO registries showed a significant correlation of the CYP3A4_rs11773597 and CYP2C9_rs1799853 variants with changes in DAS28 after the administration of anti-TNF drugs (P = 0.00074 and P = 0.006, respectively). An overall haplotype analysis also showed that the ESR2_GGG haplotype significantly associated with a reduced chance of having poor response to anti-TNF drugs (P = 0.0009). Finally, a ROC curve analysis confirmed that a model built with eight steroid hormone-related variants significantly improved the ability to predict drug response compared with the reference model including demographic and clinical variables (AUC = 0.633 vs. AUC = 0.556; P_{LR_test} = 1.52 × 10^-6). These data together with those reporting that the CYP3A4 and ESR2 SNPs correlate with the expression of TRIM4 and ESR2 mRNAs in PBMCs (ranging from P = 1.98 × 10^-6 to P = 2.0 × 10^-35), and that the CYP2C9_rs1799853 SNP modulates the efficiency of multiple drugs, suggest that steroid hormone-related genes may have a role in determining the response to anti-TNF drugs.KEY POINTS• Polymorphisms within the CYP3A4 and CYP2C9 loci correlate with changes in DAS28 after treatment with anti-TNF drugs.• A haplotype including eQTL SNPs within the ESR2 gene associates with better response to anti-TNF drugs.• A genetic model built with eight steroid hormone-related variants significantly improved the ability to predict drug response.

Involvement of blood mononuclear cells in the infertility, age-associated diseases and cancer treatment

Blood mononuclear cells consist of T cells and monocyte derived cells. Beside immunity, the blood mononuclear cells belong to the complex tissue control system (TCS), where they exhibit morphostatic function by stimulating proliferation of tissue stem cells followed by cellular differentiation, that is stopped after attaining the proper functional stage, which differs among various tissue types. Therefore, the term immune and morphostatic system (IMS) should be implied. The TCS-mediated morphostasis also consists of vascular pericytes controlled by autonomic innervation, which is regulating the quantity of distinct tissues in vivo. Lack of proper differentiation of tissue cells by TCS causes either tissue underdevelopment, e.g., muscular dystrophy, or degenerative functional failures, e.g., type 1 diabetes and age-associated diseases. With the gradual IMS regression after 35 years of age the gonadal infertility develops, followed by a growing incidence of age-associated diseases and cancers. Without restoring an altered TCS function in a degenerative disease, the implantation of tissue-specific stem cells alone by regenerative medicine can not be successful. Transfused young blood could temporarily restore fertility to enable parenthood. The young blood could also temporarily alleviate aging diseases, and this can be extended by substances inducing IMS regeneration, like the honey bee propolis. The local and/or systemic use of honey bee propolis stopped hair and teeth loss, regressed varicose veins, improved altered hearing, and lowered high blood pressure and sugar levels. Complete regression of stage IV ovarian cancer with liver metastases after a simple elaborated immunotherapy is also reported.

Estradiol-potentiated cadherin-11 in synovial membrane involves in temporomandibular joint inflammation in rats

Estrogen is involved in inflammation/pain of temporomandibular joint (TMJ), but the underlying mechanisms are largely unknown. Cadherin-11 plays an essential role in synovial inflammation. This study examined whether estrogen could potentiate cadherin-11 in synoviocytes and contribute to TMJ inflammatory pain. Female rats were ovariectomized, treated with increasing doses of 17β-estradiol for 10 days, and injected intra-articularly with complete Freund's adjuvant to induce TMJ inflammation. The expression of cadherin-11 in synovial membrane was evaluated. TMJ pain was blocked with intra-articular injection of anti-cadherin-11 antibody and evaluated by head withdrawal threshold. Primary TMJ synoviocytes were treated with estradiol and tumor necrosis factor (TNF)-α or blocked with anti-cadherin-11 antibody to assess the expression of cadherin-11, interleukin (IL)-6, cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS). We observed that estradiol potentiated the inflammation-induced expression of cadherin-11 in the synoviocytes of synovial membrane from inflamed TMJ. Estradiol induced cadherin-11 expression in a dose- and time-dependent manner in primary synoviocytes and further potentiated the induction of cadherin-11 by TNF-α in synoviocytes. Furthermore, an estrogen receptor antagonist or a NF-κB inhibitor partially blocked the effects of estradiol on cadherin-11 induction in the synovial membrane. Blocking cadherin-11 partially reversed the TMJ inflammatory pain and estradiol-potentiated proliferation of synovial lining cells accompanied with iNOS expression. In addition, blocking cadherin-11 reversed TNF-α-induced and estradiol-potentiated transcription of IL-6, COX-2, and iNOS in primary synoviocytes. These results suggest that estrogen aggravated TMJ inflammatory pain partially through cadherin-11-mediated release of proinflammatory cytokines and enzymes in the synoviocytes.

Aromatase and regulation of the estrogen-to-androgen ratio in synovial tissue inflammation: common pathway in both sexes

Sex hormones play an active role in inflammatory responses, with androgens being anti-inflammatory, whereas estrogens have both pro- and anti-inflammatory effects. In rheumatoid arthritis (RA) patients, low levels of androgens and high levels of estrone are found in the synovial fluid. Aromatase is the key enzyme for the conversion of androgens into estrogens. Proinflammatory cytokines stimulate aromatase activity so that the inflammatory milieu can induce conversion of androgens to estrogens. Moreover, testosterone inhibits aromatase activity. As local androgen levels are low in RA, this can contribute to high aromatase activity in the synovium. Importantly, aromatase-converted estrogens are converted into proproliferative and proinflammatory 16-hydroxylated estrogens. A hormone involved in aromatase activity is vitamin D, which downregulates aromatase in human RA macrophages. Collectively, evidence suggests a key role of aromatase in sex hormone balance during chronic inflammation and points to the importance of vitamin D as a possible new tool for aromatase modulation.

Upregulation of TLR2 expression is induced by estrogen via an estrogen-response element (ERE)

TLR2 and estrogen are both thought to be involved in the pathogenesis of RA; however, it is unknown if there is an association between estrogen and TLR2. In this report, we treated PMA-differentiated THP-1 cells with 17β-estradiol (E2) and observed increases in TLR2 mRNA and protein levels by real-time quantitative PCR and western blot. Transfection of THP-1 cells with a series of 5'-deleted TLR2 promoter-luciferase constructs revealed that E2 enhanced TLR2 transcriptional activity in an estrogen receptor alpha (ERα)-dependent pattern. An estrogen receptor response element (ERE) was identified 251 bases upstream of the TLR2 promoter, and electrophoretic mobility shift assay and chromatin immunoprecipitations showed ERα binding was increased by E2. In summary, this work demonstrated that TLR2 is a new estrogen-regulated gene whose expression is upregulated through the interaction of ERα with an ERE in the promoter region.

Sympathetic nerve fiber repulsion: testing norepinephrine, dopamine, and 17β-estradiol in a primary murine sympathetic neurite outgrowth assay

Loss of sympathetic nerve fibers (SNFs) occurs in inflamed tissue; and select semaphorins, upregulated during inflammation, stimulate repulsion/loss of SNFs. However, it is unknown whether other factors released locally in inflamed tissue, such as norepinephrine, dopamine, and 17β-estradiol, are also repellent. In order to study the effects of hormones on SNF repulsion, an SNF outgrowth assay was used. The repellent activity of semaphorins 3C was weaker than of semaphorin 3F. Tumor necrosis factor α (TNF-α) repelled nerve fibers with moderate to strong effects (from 0-100% repulsion). High concentrations of dopamine and norepinephrine (10(-6) M) induced weak but significant nerve fiber repulsion (up to 20%). Norepinephrine at 10(-8) M was comparable with 10(-6) M at inducing nerve fiber outgrowth. Stimulation with low concentrations of 17β-estradiol (10(-10) M, but not 10(-8) M) repelled SNFs. These results demonstrate that not only specific axon guidance molecules, such as semaphorins 3F and 3C, but also hormonal factors and TNF-α influence SNF repulsion and outgrowth.

Influence of sensitization and allergen provocation procedures on the development of allergen-induced bronchial hyperreactivity in conscious, unrestrained guinea-pigs

The effects of different sensitization and allergen provocation regimens on the development of allergen-induced bronchial hyperreactivity (BHR) to histamine were investigated in conscious, unrestrained guinea-pigs. Similar early and late phase asthmatic reactions, BHR for inhaled histamine after the early (6 h) as well as after the late reaction (24 h), and airway inflammation were observed after a single allergen provocation in animals sensitized to produce mainly IgG or IgE antibodies, respectively. Repeating the allergen provocation in the IgE-sensitized animals after 7 days, using identical provocation conditions, resulted in a similar development of BHR to histamine inhalation. Repetition of the allergen provocation during 4 subsequent days resulted in a decreased development of BHR after each provocation, despite a significant increase in the allergen provocation dose necessary to obtain similar airway obstruction. The number of inflammatory cells in the bronchoalveolar lavage was not significantly changed after repeated provocation, when compared with a single allergen provocation. Finally, we investigated allergen-induced bronchial hyperreactivity by repetition of the sensitization procedure at day 7 and 14 (booster), followed by repeated allergen provocation twice a week for 5 weeks. Surprisingly, no BHR to histamine could be observed after either provocation, while the number of inflammatory cells in the bronchoalveolar lavage fluid after 5 weeks was enhanced compared with controls. These data indicate that both IgE and IgG sensitized guinea-pigs may develop bronchial hyperreactivity after a single allergen provocation. Repeated allergen exposure of IgE sensitized animals causes a gradual fading of the induced hyperreactivity despite the on-going presence of inflammatory cells in the airways, indicating a mechanism of reduced cellular activation.

Androgen metabolism and inhibition of interleukin-1 synthesis in primary cultured human synovial macrophages

The presence of androgen receptors on synovial macrophages in human normal and rheumatoid synovial tissues has been described previously. It is now reported that primary cultured human macrophages obtained from normal and rheumatoid synovia express functional androgen receptors. We have investigated the capacity of cultured macrophages to metabolize androgens and have found that these cells were capable of metabolizing testosterone to the bioactive metabolite dihydrotestosterone. Therefore, macrophages contain the key enzymes of steroidogenesis, in particular the 5α-treductase. Furthermore, interleukin-1β production by primary cultured rheumatoid macrophages was analysed, following exposure to physiological concentrations of testosterone (10⁻⁸ M). A significant decrease of IL-1β levels in conditioned media after 24 h (p < 0.05) was observed. It is concluded that androgens may act directly on human macrophages and may interfere with some of their functions via receptor-dependent mechanisms.

The effect of ESR1 and ESR2 gene polymorphisms on the outcome of rheumatoid arthritis treatment with leflunomide

AIM

Leflunomide is the drug used in the therapy for rheumatoid arthritis (RA). Previous studies indicated that the efficacy of the therapy with antirheumatic drugs is more effective in men than in women. Moreover, estrogens can decrease the anti-inflammatory action of leflunomide. Estrogens act through the estrogen receptors ESR1 and ESR2. In ESR1 and ESR2 genes, several polymorphisms have been detected. The aim of the present study was to examine the association between polymorphisms in the ESR1 and ESR2 genes and the response to treatment of RA patients with leflunomide.

MATERIALS & METHODS

The study was carried out on 115 women, mean age 54.1 ± 11.0 years, diagnosed with RA and treated with leflunomide (20 mg daily).

RESULTS

Our results indicated a better response to treatment in patients with ESR1 rs9340799 AA and rs2234693 TT genotypes after 12 months of therapy. In these patients, the improvement of erythrocyte sedimentation rate, patient's global assessment of disease activity on a 100 mm visual analog scale and disease activity score values was greater than in patients with other genotypes. The ESR1 rs9340799-rs2234693 A-T haplotype was associated with a better response to treatment, the G-C haplotype with a worse response and the A-C haplotype was neutral. There were no statistically significant associations of response to treatment with ESR2 gene rs4986938 and rs1256049 polymorphisms.

CONCLUSION

The results of the present study suggest that ESR1 gene polymorphisms in females with RA may be associated with the response to treatment with leflunomide.

Estrogen and inflammation modulate estrogen receptor alpha expression in specific tissues of the temporomandibular joint

BACKGROUND

Estrogen is known to play role in temporomandibular joint (TMJ) disorders and estrogen effects can be mediated by estrogen receptor (ER) alpha present in the TMJ. Cells expressing the estrogen receptor ERalpha are present in the temporomandibular joint (TMJ) but changes in expression due to estrogen and inflammation have not been characterized. In this study, ERalpha protein content and the number of cells expressing ERalpha was measured in 17 beta-estradiol-treated rats after inflammation was induced in the TMJ.

METHODS

Sixteen ovariectomized female rats were divided into two groups such that one group received 17 beta estradiol (E2) and the other was given vehicle (VEH). Groups were then subdivided further, one received injections of saline and the other received Complete Freund's adjuvant (CFA) within the superior joint space of the TMJ. Thus the four groups include no E2/saline, E2/saline, no E2/CFA and E2/CFA. After treatment, the rats were sacrificed, and the TMJ anterior, disc, retrodiscal and synovial tissues were analyzed by western blot and immunocytochemistry. Positive stained cells were counted using a Nikon epifluorescent microscope.

RESULTS

The western blot showed that ERalpha protein significantly decreased with inflammation. The number of ERalpha-positive cells in the TMJ was not affected by inflammation or 17 beta-estradiol with exception of the retrodiscal tissue. In the retrodiscal tissue 17 beta-estradiol significantly decreased the number of ERalpha-positive cells but only in a non-inflamed joint.

CONCLUSIONS

In conclusion, inflammation and 17 beta-estradiol can modulate ERalpha expression in the TMJ but the effects are tissue specific.

A prospective study of androgen levels, hormone-related genes and risk of rheumatoid arthritis

Introduction

Rheumatoid arthritis (RA) is more common in females than males and sex steroid hormones may in part explain this difference. We conducted a case–control study nested within two prospective studies to determine the associations between plasma steroid hormones measured prior to RA onset and polymorphisms in the androgen receptor (AR), estrogen receptor 2 (ESR2), aromatase (CYP19) and progesterone receptor (PGR) genes and RA risk.

Methods

We genotyped AR, ESR2, CYP19, PGR SNPs and the AR CAG repeat in RA case–control studies nested within the Nurses' Health Study (NHS), NHS II (449 RA cases, 449 controls) and the Women's Health Study (72 cases, and 202 controls). All controls were matched on cohort, age, Caucasian race, menopausal status, and postmenopausal hormone use. We measured plasma dehydroepiandrosterone sulfate (DHEAS), testosterone, and sex hormone binding globulin in 132 pre-RA samples and 396 matched controls in the NHS cohorts. We used conditional logistic regression models adjusted for potential confounders to assess RA risk.

Results

Mean age of RA diagnosis was 55 years in both cohorts; 58% of cases were rheumatoid factor positive at diagnosis. There was no significant association between plasma DHEAS, total testosterone, or calculated free testosterone and risk of future RA. There was no association between individual variants or haplotypes in any of the genes and RA or seropositive RA, nor any association for the AR CAG repeat.

Conclusions

Steroid hormone levels measured at a single time point prior to RA onset were not associated with RA risk in this study. Our findings do not suggest that androgens or the AR, ESR2, PGR, and CYP19 genes are important to RA risk in women.

CD56bright cells increase expression of {alpha}4 integrin at ovulation in fertile cycles

Leukocyte content of human endometrium changes rapidly after ovulation, particularly as a result of gains in CD56(bright) uterine NK (uNK) cells. We have proposed that uNK precursor cells are found within the blood CD56(bright) pool and are recruited to decidualizing endometrium through functional changes in their adhesion molecules and chemokine receptors. This study sought to quantify alterations in adhesion molecules, cytokines, chemokines, and receptors induced in circulating CD56(+) cells of fertile and infertile women by ovulation. Blood was drawn from 12 fertile volunteers and six female-infertility patients at Menstrual Cycle Day (d) 5 and on the day following the preovulatory surge of luteinizing hormone (LH). CD56(bright), CD56(dim), and CD56(+)CD3(+) cell subsets were isolated and evaluated by flow cytometry, quantitative PCR, or Western blotting. In CD56(bright) cells from fertile but not infertile women, alpha(4) integrin increased between d5 and the preovulatory LH surge. CD56(dim) and NKT cells did not show a change in alpha(4) integrin but differed significantly between fertile and infertile donors, and infertile donors had reduced homing molecule expression in CD56(dim) and NKT cells, and at ovulation, their NKT cells showed elevated cytokine production. None of the circulating CD56(+) cell subsets had transcripts for receptors for estrogen, progesterone, LH, or prolactin. Thus, immunological events associated with the LH surge induce alterations in all subsets of CD56(+) cells, and the unique induction of alpha(4) integrin in CD56(bright) cells of fertile women constitutes a potential method to promote uterine homing.

Could hormones make a difference in the treatment of juvenile rheumatoid arthritis?

Adrenal androgens dehydroepiandrosterone (DHEA; prasterone) and its sulphated form (DHEA-S) are among the most abundant hormonal steroids in men and nonpregnant women. Deficiencies of these adrenal androgens are associated with autoimmune disorders such as rheumatoid arthritis (RA). Recent studies from our laboratory have also identified low levels of adrenal androgens in the serum and synovial fluid of patients with juvenile rheumatoid arthritis (JRA). These findings support and complement those already published for RA and other autoimmune diseases. Because of the paucity of data on the hormonal status of patients with JRA, studies on the relationship between hypoandrogenicity and predisposition to develop JRA, and/or disease progression have not been conducted. In addition, despite the rapid expansion of research in the clinical use of these adrenal androgens in hyperlipidaemia, atherosclerosis, obesity, diabetes mellitus, insulin resistance and hypertension, their potential beneficial effects in JRA/RA have not been fully investigated. In fact, clinical trials of adrenal androgens in RA have only been conducted for the treatment of systemic lupus erythematosus. Further studies using prospective approaches are necessary to provide a unified consensus on the hormonal status of patients with JRA (as well as those with RA). This overview of our knowledge of the putative role(s) of hormones in arthritis will hopefully stimulate researchers in basic science and rheumatologists to synergistically collaborate in the effective translation of such knowledge to new clinical approaches.

The complex role of estrogens in inflammation

There is still an unresolved paradox with respect to the immunomodulating role of estrogens. On one side, we recognize inhibition of bone resorption and suppression of inflammation in several animal models of chronic inflammatory diseases. On the other hand, we realize the immunosupportive role of estrogens in trauma/sepsis and the proinflammatory effects in some chronic autoimmune diseases in humans. This review examines possible causes for this paradox. This review delineates how the effects of estrogens are dependent on criteria such as: 1) the immune stimulus (foreign antigens or autoantigens) and subsequent antigen-specific immune responses (e.g., T cell inhibited by estrogens vs. activation of B cell); 2) the cell types involved during different phases of the disease; 3) the target organ with its specific microenvironment; 4) timing of 17beta-estradiol administration in relation to the disease course (and the reproductive status of a woman); 5) the concentration of estrogens; 6) the variability in expression of estrogen receptor alpha and beta depending on the microenvironment and the cell type; and 7) intracellular metabolism of estrogens leading to important biologically active metabolites with quite different anti- and proinflammatory function. Also mentioned are systemic supersystems such as the hypothalamic-pituitary-adrenal axis, the sensory nervous system, and the sympathetic nervous system and how they are influenced by estrogens. This review reinforces the concept that estrogens have antiinflammatory but also proinflammatory roles depending on above-mentioned criteria. It also explains that a uniform concept as to the action of estrogens cannot be found for all inflammatory diseases due to the enormous variable responses of immune and repair systems.

Estrogen receptor-beta is the predominant estrogen receptor subtype in normal human synovia

OBJECTIVE

Joint pain increases after menopause with more than 50% of woman suffering from arthralgies. Since pain and inflammation of joints originate from synovial tissue, we aimed to discover whether estrogen receptors are present in the human synovia.

METHODS

This in vitro study was performed on samples of human synovial tissue, obtained from pre- (n = 8) and postmenopausal woman (n = 11) and men (n = 5) following surgery due to traumatic lesions. Fresh synovial tissue specimens were assessed for the localization as well as the presence of estrogen receptor-alpha (ER alpha) and estrogen receptor-beta (ER beta) by means of immunohistochemistry, as well as Western blot and reverse transcriptase-polymerase chain reaction (RT-PCR), respectively.

RESULTS

ER beta protein and mRNA were found to be equally and highly expressed in synovial stroma and lining cells of all explants independent of sex or menopausal status. In contrast, weak ER alpha staining was localized in the synovial lining cells in only three of 24 explants. ER alpha protein was found to be weakly expressed in three of ten explants. ER alpha mRNA was found with highly variable amounts in seven of ten explants.

CONCLUSION

In view of our observation that ER beta but not ER alpha is expressed regularly in normal human synovia in high amounts, we propose that estrogen could play a significant role in synovial membrane function in women and men, operating preferably via the ER beta isoform.

Quantitative determination of steroid hormone receptor positive cells in the synovium of patients with rheumatoid arthritis and osteoarthritis: is there a link to inflammation?

BACKGROUND

Steroid hormone receptors such as glucocorticoid receptors, androgen receptors, and oestrogen receptors alpha (ERalpha) and beta (ERbeta) have been identified in synovial cells of patients with rheumatoid arthritis and osteoarthritis.

OBJECTIVES

To find a quantitative relationship between the number of receptor positive cells and markers of inflammation, and to compare the two groups of patients with rheumatoid arthritis and osteoarthritis.

METHODS

A total of 36 patients with rheumatoid arthritis (n = 17) and osteoarthritis (n = 19) were included, and receptor positive cells and cellular markers of synovial inflammation were quantified by immunohistochemistry and ELISA (interleukin 6 (IL6) and IL8).

RESULTS

Patients with rheumatoid arthritis showed a higher degree of histologically determined inflammation compared with those with osteoarthritis. However, synovial density of gluco-corticoid receptor positive (GR+), androgen receptor positive (AR+), ERalpha+ and ERbeta+ cells were not different among patients with rheumatoid arthritis and osteoarthritis. In patients with osteoarthritis, the density of GR+ cells positively correlated with the density of AR+, ERalpha+ and ERbeta+ cells (p = 0.007), which was not observed in patients with rheumatoid arthritis. This indicates positively coupled steroid hormone receptor expression in patients with osteoarthritis but not in those with rheumatoid arthritis. In patients with rheumatoid arthritis, secretion of synovial IL6 and IL8 positively correlated with the density of ERalpha+ and ERbeta+ cells (not with gluco-corticoid receptor and androgen receptor), which was not found in the synovium of patients with osteoarthritis. This indicates that inflammatory factors might up regulate the expression of oestrogen receptors in patients with rheumatoid arthritis, or vice versa.

CONCLUSIONS

In patients with osteoarthritis, expression of different steroid receptors is positively coupled, which was not observed in the synovium of patients with rheumatoid arthritis. This uncoupling phenomenon in rheumatoid arthritis might lead to an imbalance of the normal synovial homeostasis.

Raloxifene reduces urokinase-type plasminogen activator-dependent proliferation of synoviocytes from patients with rheumatoid arthritis

Extracellular fibrinolysis, controlled by the membrane-bound fibrinolytic system, is involved in cartilage damage and rheumatoid arthritis (RA) synovitis. Estrogen status and metabolism seem to be impaired in RA, and synoviocytes show receptors for estrogens. Our aims in this study were to evaluate in healthy and RA synoviocytes the effects of Raloxifene (RAL), a selective estrogen receptor modulator (SERM), on: proliferation; the components of the fibrinolytic system; and chemoinvasion. The effects of RAL were studied in vitro on synoviocytes from four RA patients and four controls. Proliferation was evaluated as cell number increase, and synoviocytes were treated with 0.5 microM and 1 microM RAL with and without urokinase-plasminogen activator (u-PA) and anti-u-PA/anti-u-PA receptor (u-PAR) antibodies. Fibrinolytic system components (u-PA, u-PAR and plasminogen activator inhibitor (PAI)-1) were assayed by ELISA with cells treated with 0.5 microM and 1 microM RAL for 48 h. u-PA activity was evaluated by zymography and a direct fibrinolytic assay. U-PAR/cell and its saturation were studied by radioiodination of u-PA and a u-PA binding assay. Chemoinvasion was measured using the Boyden chamber invasion assay. u-PA induced proliferation of RA synoviocytes was blocked by RAL (p < 0.05) and antagonized by antibodies alone. The inhibitory effect of RAL was not additive with u-PA/u-PAR antagonism. RA synoviocytes treated with RAL showed, compared to basal, higher levels of PAI-1 (10.75 +/- 0.26 versus 5.5 +/- 0.1 microg/10(6) cells, respectively; p < 0.01), lower levels of u-PA (1.04 +/- 0.05 versus 3.1 +/- 0.4 ng/10(6) cells, respectively; p < 0.001), and lower levels of u-PAR (11.28 +/- 0.22 versus 23.6 +/- 0.1 ng/10(6) cells, respectively; p < 0.001). RAL also significantly inhibited u-PA-induced migration. Similar effects were also shown, at least partially, in controls. RAL exerts anti-proliferative and anti-invasive effects on synoviocytes, mainly modulating u-PAR and, to a lesser extent, u-PA and PAI-1 levels, and inhibiting cell migration and proliferation.

17-Beta estradiol enhances prostaglandin E2 production in human U937-derived macrophages

Prostaglandins (PGs) are potent eicosanoid lipid mediators that have been implicated in numerous homeostatic functions and inflammation. Estrogens have been shown to regulate the expression of genes in lipid metabolism in many cellular systems. In this study, the activation of macrophages and the modulation of PG release by estrogens were examined. The effects of 17-alpha and 17-beta estradiols, phytoestrogen Genistein and several selective estrogen receptor modulators on the release of PGE2 were investigated in human U937-derived macrophages. 17-Beta estradiol caused an enhancement of PGE2 production in a time- and dose-dependent manner. Treatment of macrophages with 17-beta estradiol elicited an increased arachidonic acid (AA) release and an up-regulation of both cyclooxygenesis-1 and cyclooxygenesis-2 enzymes at both the transcript and protein levels. In addition, immunostaining of nuclear estrogen receptor alpha and the observation of ICI182 780 blockade of PGE2 production indicated that 17-beta estradiol-induced PGE2 release was mainly through nuclear estrogen receptor alpha.

Neuroendocrinology of female aging

BACKGROUND

Because the average human life span has increased, a greater part of more women's lives will be lived in a hypoestrogenic state.

OBJECTIVE

This article provides an overview of our current knowledge of the neuroendocrine processes in the aging female brain.

METHODS

Using the search terms cardiovascular disease, cognition, dementia, depression, estrogens, female aging, gonadotropins, immune function, mood, neuroendocrinology, neurotransmitters, osteoporosis, and ovarian steroids, a review of English-language literature on the MEDLINE database was conducted from 1970 through June 2004.

RESULTS

It is thought that the temporal patterns of neural signals are altered during middle age, leading to cessation of reproductive cycles, and that the complex interplay of ovarian and hypothalamic/pituitary pacemakers becomes increasingly dysfunctional with aging, ultimately resulting in menopause. Estrogen deficiency is associated with low mood, whereas estrogen therapy tends to be linked with improvements in measures of well-being and a decline in depression scores. It is likely that these effects of estrogens are mediated through changes in the metabolism of serotonin and nor epinephrine. Evidence exists to support the role of estrogens in specific effects on cognitive functioning in women, enhancing aspects of verbal memory, abstract reasoning, and information processing. Significant gender dimorphism is evident in both humoral and cell-mediated immune responses. The effects of estrogens on the cardiovascular system are complex; recent evidence suggests a negative role for oral estrogen in primary and secondary prevention of cardiovascular events. Additionally, estrogens increase the risk of stroke, and estrogen deficiency influences the pathogenesis of osteoporosis in both men and women.

CONCLUSIONS

Changes in the neuroendocrine system due to the loss of ovarian function at menopause have an important biological role in the control of reproductive and nonreproductive functions, and regulate mood, memory, cognition, behavior, immune function, the locomotor system, and cardiovascular functions. More detailed insights are needed into the complex mechanisms of neuroendocrine alterations with aging.

17 beta-estradiol regulates cytokine release through modulation of CD16 expression in monocytes and monocyte-derived macrophages

OBJECTIVE

Macrophages release cytokines, such as tumor necrosis factor alpha (TNF alpha), interleukin-1 (IL-1), and IL-6, which modulate the symptoms of rheumatoid arthritis (RA). Macrophage release of these cytokines can be modulated by estrogen. Fc gamma receptor type IIIA (CD16a) is a receptor expressed on macrophages that selectively binds IgG molecules, an important rheumatoid factor in RA. Binding of CD16 by anti-CD16 monoclonal antibodies stimulates macrophage cytokine release. We undertook this study to test the hypothesis that decreased concentrations of estrogen (17 beta-estradiol) directly cause an increase in CD16 expression, resulting in increased release of proinflammatory cytokines from monocytes and/or macrophages upon receptor binding.

METHODS

THP-1 cells and female human primary monocytes and monocyte-derived macrophages were treated with no 17 beta-estradiol, physiologic levels (1 x 10(-8)M) of 17 beta-estradiol, or 1 x 10(-8)M 17 beta-estradiol followed by withdrawal of 17 beta-estradiol. Surface expression of CD16 and CD16 messenger RNA was measured using fluorescence-activated cell sorting (FACS) and semiquantitative reverse transcription-polymerase chain reaction, respectively. Cytokine release from 17 beta-estradiol-treated or untreated monocytes was then quantitated by enzyme-linked immunosorbent assay and FACS after crosslinking the receptor with anti-CD16 antibodies.

RESULTS

CD16 transcript significantly increased in macrophage-like THP-1 cells and in primary, peripheral blood macrophages in the absence of 17 beta-estradiol, and the observed increase in message was dependent on transcription. CD16 receptor levels on CD14+, transforming growth factor beta-treated primary monocytes also increased in cells deprived of 17 beta-estradiol. Analysis of the cytokines released showed that CD16 crosslinking stimulated significant increases in TNF alpha, IL-1 beta, and IL-6 due to the absence of estrogen.

CONCLUSION

Estrogen can modulate proinflammatory cytokine release from activated monocytes and/or macrophages, in part through modulation of CD16 expression.

17-Beta-estradiol regulates expression of genes that function in macrophage activation and cholesterol homeostasis

Macrophage activation and cholesterol processing can be affected by changes in estrogen concentrations. However, there is a paucity of information about the genes and mechanisms regulating this estrogen effect. In primary monocyte-derived macrophages we detected transcript and protein for estrogen receptor beta (ERbeta). Determination of genes regulated by estrogen was completed using cDNA arrays and semiquantitative RT-PCR on RNA isolated from macrophages cultured in serum free media containing (5-10) x 10(-9)M 17-beta-estradiol and subsequently deprived of estrogen for a 24h period. The data indicate that the transcript levels of interleukin 1 receptor antagonist (IL-1ra), beta 2-microglobulin, annexin XI and the LXR(alpha) receptor significantly increased and that Ly-GDI transcript levels significantly decreased after estrogen withdrawal; data congruent with estrogen depletion regulating macrophage inflammatory and biochemical processes. Treatment of THP-1 cells with phorbol 12-myristate-13-acetate in the presence or absence of estrogen indicate that differentiation to a macrophage-like cell type was a prerequisite for production of the estrogen response. In addition, experiments using cycloheximide treatment, that blocks nascent protein synthesis, indicated that estrogen withdrawal affected the transcript levels of LXR(alpha) and IL-1ra through dissimilar pathways.

A role for sex steroids in autoimmune diseases: a working hypothesis and supporting data

In recent years there has been a continuingly increasing interest in novel research subjects, as yet poorly explored, either because they relate to aspects previously thought to be marginal with respect to classical fields of investigation, or because they require both specialized competence and intense cross-talk by researchers from disparate areas. The potential interaction between immunity and cancer has generated a remarkable number of studies, including those related to the newly explored immune-neuro-endocrine system. In this paper, we review a few autoimmune diseases as examples of a mutual relationship between immune diseases and malignancies. We also review our previous studies on patients with rheumatoid arthritis (RA). In particular, aiming to define the hormone-responsive or -sensitive status of synovial tissues and cells, we have inspected different endocrine end-points, including (1) high- and low-affinity sites of androgen and estrogen binding; (2) the activity of key enzymes of steroid metabolism; and (3) the hormonal profile of synovial fluids as an indication of local endocrine milieu. Overall, our data provide convincing evidence for synovial macrophage-like cells and a subset of T lymphocytes to be considered as target cells for gonadal steroids. This provides a basis for developing new strategies for alternative treatments of RA and possibly unveils novel perspectives in both research and the clinic for other autoimmune diseases as well. In addition, the association of autoimmunity and cancer may disclose promising new avenues of research linking steroid hormones, the immune system, and malignant transformation.

Effects of androgens on T and B lymphocyte development

The sexually dimorphic nature of normal immune responses and the remarkably higher incidence of autoimmune diseases in females have suggested a role for gonadal steroid hormones as modulators of immune system function. We have investigated the effects of androgens on the development of lymphocytes in the thymus and bone marrow. Expression of the androgen receptor, the ligand-activated transcription factor that mediates hormone actions, has been documented in lymphoid and nonlymphoid cells of thymus and bone marrow, but not in mature peripheral lymphocytes. This expression pattern suggests that the major impact of androgens must be on the developmental maturation of T and B lymphocytes rather than on the mature effector cells. Recent experiments have explored whether developing lymphoid precursors are the direct targets of androgen action or whether supporting cells, such as thymic epithelial cells and bone marrow stromal cells, are required for the receptor-mediated effects of androgens on lymphoid cell development. Bone marrow transplantation techniques using an androgen-resistant mouse strain permit the creation of chimeric mice with androgen receptor-defective lymphoid or epithelial/stromal cellular compartments. Hormonal manipulation experiments in these chimeric animals have suggested that thymic epithelial cells and bone marrow stromal cells are mediators of androgenic effects on immature lymphocytes. The long-range goal of these studies is to understand the basis for the disproportionate occurrence of autoimmune diseases in females.

Phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) up-regulates the expression of estrogen receptors in human THP-1 leukemia cells

In the present work, we have inspected expression of estrogen receptors (ER) and their regulation by the phorbol diester 12-O-tetradecanoylphorbol 13-acetate (TPA) in a leukemic cell line, the THP-1 cells, using multiple experimental approaches. Firstly, ligand binding assay (LBA) revealed that control (unstimulated) THP-1 cells express type I (high affinity, limited capacity) ER in the nuclear fraction only, whilst treatment of cells with TPA resulted in the appearance of type I ER in the soluble fraction as well, with the 50 ng/ml dose and the 48 h incubation time being the most effective experimental condition. A concomitant increase of type II ER was also seen in both soluble and nuclear cell fractions. Unstimulated THP-1 cells were found to be ER negative by immunocytochemistry; conversely, cells exposed to 50 ng/ml TPA for 48 h stained positively for ER, with the majority of cells having a strong nuclear staining. Scrutiny of ER mRNA expression using reverse transcriptase-polymerase chain reaction showed the presence of a wild type ER transcript in both control and TPA-treated THP-1 cells, though levels of ER mRNA were found to be comparatively higher in the latter. This combined evidence would imply that the TPA-induced differentiation of THP-1 cells is accompanied by the rise of high affinity (type I) ER, suggesting that estrogens may play a role in the regulation of macrophage activity during the inflammatory and/or the immune response.

Non-steroidal anti-oestrogens inhibit the differentiation of synovial macrophages into dendritic cells

BACKGROUND

Dendritic cells (DC) have been suggested to play an important role in the pathogenesis of rheumatoid arthritis (RA). Agents that inhibit DC differentiation and function may have a therapeutic value in the treatment of RA.

OBJECTIVE

To examine the effect of the non-steroidal anti-oestrogens toremifene and tamoxifen on the differentiation of synovial fluid (SF) macrophages into DC.

METHODS

SF macrophages from patients with RA were cultured with interleukin (IL)-4 and granulocyte/macrophage colony-stimulating factor (GM-CSF) in the presence or absence of anti-oestrogens. The expression of cell surface markers on SF antigen-presenting cells (APC) was studied by flow cytometry. The capacity of SF APC to stimulate allogeneic T cells was studied using the mixed lymphocyte reaction. The production of tumour necrosis factor-alpha, IL-10 and transforming growth factor-beta1 was studied using ELISA.

RESULTS

Anti-oestrogens inhibited the differentiation of SF macrophages into DC and the capacity of SF macrophage-derived DC to stimulate allogeneic T cells.

CONCLUSIONS

By inhibiting the differentiation of SF macrophages into DC, non-steroidal anti-oestrogens may have beneficial effects in RA.

Sex hormone adjuvant therapy in rheumatoid arthritis

RA is an autoimmune rheumatic disorder resulting from the combination of several predisposing factors, including the relation between epitopes of possible triggering agents and histocompatibility epitopes, the status of the stress response system, and the sex hormone status. Estrogens are implicated as enhancers of humoral immunity, and androgens and progesterone are natural immune suppressors. Sex hormone concentrations have been evaluated in RA patients before glucocorticoid therapy and have frequently been found to be altered, especially in premenopausal women and male patients. In particular, low levels of gonadal and adrenal androgens (testosterone and DHT, DHEA and DHEAS) and a reduced androgen:estrogen ratio have been detected in body fluids (i.e., blood, synovial fluid, smears, saliva) of male and female RA patients. These observations support a possible pathogenic role for the decreased levels of the immune-suppressive androgens. Exposure to environmental estrogens (estrogenic xenobiotics), genetic polymorphisms of genes coding for hormone metabolic enzymes or receptors, and gonadal disturbances related to stress system activation (hypothalamic-pituitary-adrenocortical axis) and physiologic hormonal perturbations such as during aging, the menstrual cycle, pregnancy, the postpartum period, and menopause may interfere with the androgen:estrogen ratio. Sex hormones might exert their immune-modulating effects, at least in RA synovitis, because synovial macrophages, monocytes, and lymphocytes possess functional androgen and estrogen receptors and may metabolize gonadal hormones. The molecular basis for sex hormone adjuvant therapy in RA is thus experimentally substantiated. By considering the well-demonstrated immune-suppressive activities exerted by androgens, male hormones and their derivatives seem to be the most promising therapeutic approach. Recent studies have shown positive effects of androgen replacement therapy at least in male RA patients, particularly as adjuvant treatment. Interestingly, the increase in serum androgen metabolism induced by RA treatment with CSA should be regarded as a possible marker of androgen-mediated immune-suppressive activities exerted by CSA, at least in RA and at the level of sensitive target cells and tissues (i.e., synovial macrophages). The absence of altered serum levels of estrogens in RA patients and the reported immune-enhancing properties exerted by female hormones have represented a poor stimulus to test estrogen replacement therapy in RA. The different results obtained with OC use seem to depend on dose-related effects and the different type of response to estrogens in relation to the cytokine balance between Th1 cells (cellular immunity, i.e., RA) and Th2 cells (humoral immunity, i.e., SLE). The androgen replacement obtained directly (i.e., testosterone, DHT, DHEAS) or indirectly (i.e., antiestrogens) may represent a valuable concomitant or adjuvant treatment to be associated with other disease-modifying antirheumatic drugs (i.e., MTX, CSA) in the management of RA.

Different roles for androgens and estrogens in the susceptibility to autoimmune rheumatic diseases

It is now documented that androgens and estrogens modulate susceptibility and progression to autoimmune rheumatic diseases. At any concentration, androgens seem to be primarily suppressive on cellular and humoral immunity, whereas at physiologic concentrations, estrogens seem to enhance humoral immunity. Further research should focus on the different and frequently opposite effects exerted by physiologic and pharmacologic doses of estrogens (dose-related effects). In addition to the influence of endogenous estrogen fluctuations (i.e., during pregnancy, postpartum, menstrual periods, menopause), estrogen replacement therapy, and the use of oral contraceptives, the susceptibility to autoimmunity might be increased by the environmental estrogens (xenobiotics). Further studies must be directed to the inflammatory mediators (i.e., cytokines) that seem to alter the peripheral metabolism of sex hormones and complicate the effects of sex hormones on susceptibility to autoimmunity. Finally, genetic factors might further interfere with the roles of androgens and estrogens in selected individuals.

Estrogen enhances uptake of amyloid beta-protein by microglia derived from the human cortex

In recent years, inflammatory mechanisms have been increasingly appreciated as important steps in the pathology of Alzheimer's disease (AD). There are two pathological defects in AD: chronic inflammation and impaired clearance of amyloid beta-peptide (Abeta). In the periphery, estrogen both increases macrophage phagocytosis and has antiinflammatory effects. If estrogen had a similar effect in the CNS, it could reverse inflammatory defects in AD. Although microglia are a key component of the immune system and help clear Abeta deposits in the AD brain, little is known about the effects of estrogen on CNS microglia. Therefore, we sought to determine the relationship between estrogen treatment and internalization of Abeta by microglia by quantifying the internalization of aggregated Abeta by human cortical microglia. Abeta uptake was found to be dose- and time-dependent in cultured microglia. Increased Abeta uptake was observed at 1.5 and 24 h after addition of aggregated Abeta (50, 100, or 1,000 nM: Abeta), and this uptake was enhanced by pretreatment with estrogen. The expression of estrogen receptor (ER) beta (ER-beta) was also up-regulated by estrogen treatment. Cells cotreated with ICI 182,780, an ER antagonist, showed significantly reduced internalization of Abeta in cultured microglia. These results indicate that microglia express an ER-beta but that the effect of estrogen on enhancing clearance of Abeta may be related to the receptor-independent action of estrogen or to nonclassical ER effects of estrogen. Thus, stimulation of the ER might contribute to the therapeutic action of estrogen in the treatment of AD.

Molecular mechanisms involved in the estrogen-dependent regulation of calcineurin in systemic lupus erythematosus T cells

Previous experiments in our laboratory indicated that calcineurin expression and PP2B phosphatase activity increased when estrogen was cultured with SLE T cells but not with T cells from normal women. In this report we extended our findings to show that estrogen receptor (ER) antagonism by ICI 182,780 inhibited the estrogen-dependent increase in calcineurin mRNA and phosphatase PP2B activity indicating that estrogen action was mediated through the ER. Inhibition of de novo protein synthesis with cycloheximide suggested that the estrogen-dependent increase in T cell calcineurin mRNA was a direct effect of the ER and new protein synthesis was not required. Estrogen increased calcineurin mRNA in systemic lupus erythematosus (SLE) T cells at 6 h after the start of culture correlating with increased phosphatase activity at this same time. Phosphatase activity increased significantly (P < 0.02) in lupus T cells cultured for 8 h in estradiol-containing medium. Reverse transcription and polymerase chain amplification revealed that ER-beta and ER-alpha were expressed in female and male T cells from SLE patients and normal controls. However, calcineurin steady-state mRNA levels were unaffected by estradiol in cultured T cells from male SLE patients and normal male and female controls. These data indicate that estrogen, bound to the ER, evokes a direct increase in calcineurin expression in T cells from female lupus patients. This gender-specific response suggests that ER function is altered in women with the female predominant autoimmune disease, SLE.

The detection and comparison of angiogenesis-associated factors in pyogenic granuloma by immunohistochemistry

BACKGROUND

Pyogenic granuloma is a benign inflammatory lesion demonstrating obvious activity of angiogenesis. Female steroid hormones are believed to play important roles in the etiology because the lesion is frequently found in females with high levels of sex hormones. Few molecular mechanisms of the pathogenesis have been proposed and proven. The purpose of this study was to detect and compare the expression of angiogenesis-associated factors among healthy gingiva, gingiva from periodontitis, and pyogenic granuloma to clarify the pathogenesis of pyogenic granuloma.

METHODS

Fifteen specimens were collected from each of 3 groups of gingiva (healthy gingiva, periodontitis, and pyogenic granuloma). The subjects were age and gender matched. The specimens were processed for immunohistochemistry to detect and compare the expression of 2 angiogenesis enhancers, i.e., vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF), 2 angiogenesis inhibitors, i.e., angiostatin and thrombospondin-1 (TSP-1), and estrogen receptor (ER). Using the subject as the unit of statistical analysis, either analysis of variance or chi-square analysis was employed to show the statistically significant difference at a level P <0.05.

RESULTS

The pyogenic granuloma group expressed significantly more VEGF and bFGF than healthy gingiva and periodontitis. The positive staining of VEGF was mostly localized in the cytoplasm of macrophages and fibroblasts while that of bFGF was in the extracellular matrix of lamina propria. Angiostatin was expressed significantly less in pyogenic granuloma than the other 2 groups and was mostly localized in the nuclei of endothelial cells and epithelial cells. There was no significant difference in the expression of TSP-1 and ER among the 3 groups.

CONCLUSIONS

The results of this research suggest that the etiology of pyogenic granuloma is due to the imbalance between angiogenesis enhancers and inhibitors. Whether and how the angiogenesis-associated factors are regulated by female steroid hormones remain to be answered.

The role of the hypothalamic-pituitary-adrenal axis in rheumatoid arthritis

It has become clear that there is a bidirectional communication between the neuroendocrine and the immune system and that both systems influence each other and interact under physiological conditions and in response to inflammatory stimuli. The hypothalamic-pituitary axis plays an important role in regulating and controlling immune responses and dysfunction of the axis has been implicated in the pathogenesis of rheumatoid arthritis (RA). Corticotrophin-releasing hormone (CRH), one of the main hormones of the axis, is also released extra-hypothalamically, peripherally at the site of inflammation and may modulate inflammatory responses locally. In this chapter we will discuss the role of the hypothalamic-pituitary-adrenal (HPA) axis and peripheral CRH, its influences on immune function and what is known about the possible pathogenetic role of the HPA axis and peripheral CRH in RA.

Endocrine end-points in rheumatoid arthritis

Our previous studies are reviewed and at the same time preliminary experimental observation to the topic of endocrine end-points in autoimmune disease is introduced. To this end, we have used rheumatoid arthritis (RA), including synovial fluids and primary cultures of synovial macrophages, as a model system in order to investigate (a) expression and subcellular localization of high-affinity sites of steroid binding in immune effector cells; (b) steroid metabolic profiles in both male and female RA patients, as compared to healthy subjects; and (c) activities of key steroid enzymes that govern intratissue accumulation of sex hormones. In RA tissues and cells, the concurrent evidence for (1) androgen and/or estrogen receptors, (2) high concentrations of biologically active steroids, (3) key enzymes of steroid metabolism, and (4) significant changes of estrogen to androgen ratio, all strongly suggests that individual immune cells, including synovial macrophages, may behave as steroid-sensitive cells, namely, they may represent a target for sex steroids, supporting the hypothesis of a potential endocrine regulation of the immune response also in RA disease. In this respect, definition of several endocrine end-points may have important implications for the treatment of rheumatic disease and other immunological disorders.

Macrophages as effectors of the immunoendocrinologic interactions in autoimmune rheumatic diseases

An intricate balance between soluble mediators, released by activated cells of the immune/inflammatory systems, and products of the neuroendocrine system is implicated in the presence of an autoimmune rheumatic disease. Monocytes/macrophages contribute to autoimmune events in rheumatic diseases, such as rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE), mainly acting as antigen-processing and presenting cells in the presence of an autoimmune rheumatic disease. Clinical symptoms such as morning stiffness and gelling, at least in RA, that peak during the late night and early morning, are consistent with the hypothesis that the immune function of activated cells (i.e., Th1 cells and monocytes/macrophages) and their mediators (cytokines and reactive oxygen intermediates) is increased at these times in relation to neuroendocrine pathway rhythmicity. Therefore, monocytes/macrophages seem to be the "link" between the steroid hormone environment (i.e., gonadal hormones) and the immune response effectors. If gonadal hormones, along with cytotoxic agents, do modulate macrophage apoptosis, such an approach might offer an important pathway to the control of autoimmune diseases. In conclusion, on the basis of a more complete understanding of macrophage effector and immunoregulatory activities, on both a local and systemic level, new hopes arise from the possible development of more sophisticated antimacrophage treatments for the management of autoimmune rheumatic diseases.

Expression and localization of estrogen receptor-beta in murine and human bone

Estrogens have profound effects on bone metabolism. Cellular responses to estrogens are mediated by estrogen receptors (ERs) which belong to the nuclear receptor superfamily. Two estrogen receptors, ERalpha and ERbeta, have been cloned. Previously expression of ERalpha has been shown in osteoblasts. Here we demonstrate that the transcript for ERbeta can be detected in the human osteosarcoma cell lines (MG-63 and SaOS-2) and in cultured human osteoblast-like cells. We also show that ERbeta protein is present in nuclear extracts from these cells. Furthermore, ERbeta immunoreactivity is found in sections of murine and human bone. Murine and human osteoblast and osteocyte nuclei are immunoreactive for ERbeta. Osteoclasts are also ERbeta immunoreactive but the staining is mainly cytoplasmic. The present study demonstrates that ERbeta is present in all the cellular compartments involved in bone formation and bone resorption, both in human and in murine bone tissue.

Association of oestrogen receptor gene polymorphisms with age at onset of rheumatoid arthritis

OBJECTIVE

In view of the possible role of oestrogens in the pathogenesis of rheumatoid arthritis (RA), this study investigated the association between oestrogen receptor (OR) gene polymorphisms and RA.

METHODS

Pvu II and Xba I restriction fragment length polymorphisms of the OR gene were analysed in 70 male and 240 female patients with RA, and in 300 male and 350 female controls. The absence or presence of restriction sites were represented as P, p (Pvu II) or X, x (Xba I). The distribution of OR genotypes was compared between the RA and control subjects by sex. RA patients were divided into subgroups according to their OR genotypes, then the age at onset, seropositivity, and rheumatoid nodule positivity were compared between the subgroups.

RESULTS

The OR genotype frequency of distribution did not have significant differences between the male RA and male controls nor between the female RA and female controls. In women with RA, there was a significant difference of age at onset between the subgroups (uncorrected p = 0.047, corrected p = 0.94). Female patients with the OR genotype PPxx (homozygote of Px) tended to have developed RA at a younger age, whereas those with PPXX and ppxx (lack of Px haplotype) developed RA at an older age. In men with RA, there was no association between the OR genotype and age at onset. In seropositivity and rheumatoid nodule positivity, there was no significant difference between subgroups for either sex.

CONCLUSIONS

Some variants of the OR gene are related to the onset of RA in women in certain age periods, suggesting the role of the interaction between the OR gene and serum concentrations of oestrogen at the onset of the disease.

T lymphocytes are not the target for estradiol-mediated suppression of DTH in reconstituted female severe combined immunodeficient (SCID) mice

Oestrogen has the capacity to suppress T cell-dependent DTH. To explore the mechanisms whereby oestrogen exerts its effects on the immune system we have used SCID mice which are largely devoid of functional T and B lymphocytes, hence being unable to raise DTH, but display intact antigen-presenting capacity. Transfer of lymphocytes to SCID mice restores the DTH capacity. In order to analyse if oestrogen down-regulates DTH by a direct action on T cells we reconstituted SCID mice with either splenocytes or thymocytes from congenic C.B-17 or allogeneic B6 donor mice. Either donor or recipient mice were exposed to estradiol before cell transfer. DTH response was registered in recipient SCID mice 1 and 3 weeks after challenge with oxazolone (OXA). SCID mice receiving estradiol-exposed spleen cells from congenic or allogeneic donor mice displayed lower DTH responses compared with control mice. In contrast, SCID mice receiving estradiol-exposed thymocytes from congenic donor mice showed no significant difference in DTH response compared with control mice. Estradiol-treated SCID mice, transferred with either spleen cells or thymocytes from congenic, hormonally non-treated donors, displayed a significantly lower DTH response compared with control mice. In contrast, estradiol-treated SCID mice receiving hormonally non-treated allogeneic spleen cells showed no difference in DTH response compared with control mice. The results show that T lymphocytes are not the target cell population for estradiol-mediated suppression of DTH in reconstituted female SCID mice.

Gender differences in autoimmune diseases: estrogen increases calcineurin expression in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) predominantly affects women (9:1 compared to men) of childbearing age and often decreases its intensity in postmenopausal women, suggesting that sex hormones play a role in its pathogenesis. Comparison of steady-state levels of calcineurin mRNA using RNase protection assays revealed increased calcineurin expression in response to estradiol in cultured T cells from nine female lupus patients. Calcineurin mRNA levels did not increase significantly in T cells from eight age-matched normal control female volunteers. Estrogen-dependent calcineurin mRNA increased in a dose-dependent fashion, while progesterone and dexamethasone did not increase calcineurin mRNA in patient cells. Lupus T cell calcineurin mRNA increased in response to estradiol at 6 h but not at 3 h. Calcineurin phosphatase activity increased in lupus T cell extracts after incubation of cells with estradiol, while phosphatase activity in normal T cells was unaffected by estrogen. Calcineurin expression in T cells from patients with vasculitis and rheumatoid arthritis taking medications similar to those taken by the lupus patients was unaffected by estradiol. This study provides the first evidence for a molecular marker of estrogen action in lupus patients and suggests that estrogen-dependent changes in lupus T cell calcineurin could alter proinflammatory cytokine gene regulation and T-B cell interactions.

Spondyloarthritides in females

Few studies have been performed regarding clinical, radiological and prognostic features of females with spondyloarthropathies other than ankylosing spondylitis (AS). In AS, clinical manifestations appear similar in men and women, whereas radiological features appear more frequent and severe in males. However, no consistent differences in outcome and mortality between men and women have been disclosed. Although fetal outcome is not compromised in women with spondyloarthropathy (SpA), the interaction of pregnancy and SpA has been studied in detail only in AS. Spinal disease is unchanged while peripheral arthritis and uveitis are suppressed during childbearing. Due to possible maternal and fetal side-effects, NSAIDs must be discontinued during the last 8 weeks of pregnancy, but during lactation several NSAIDs can be used. Treatment with sulphasalazine is compatible with pregnancy and lactation. Children of AS patients exhibit a slightly increased risk of developing SpA later in life.