Regulation of natural killer cell activity by glucocorticoids, serotonin, dopamine, and epinephrine.

The immune system and the nervous system are highly complex organs composed of various different cells that must interact with each other for proper function of the system. This communication can be mediated by soluble factors. The factors released by the nervous system (neurotransmitters) differ from those released by the immune system (cytokines). Nevertheless, the nervous and immune systems can influence each other's activity because immune cells express neurotransmitter receptors, and neurons express cytokine receptors. Moreover, immune cells can synthesize and release neurotransmitters themselves, thus using neurotransmitter-mediated pathways via autocrine and paracrine mechanisms. Natural killer (NK) cells are innate lymphocytes that are important for early and effective immune reactions against infections and cancer. Many studies have shown the strong influence of stress and the nervous system on NK cell activity. This phenomenon may be one reason why chronic stress leads to a higher incidence of infections and cancer. Here, we review the effects of neuroendocrine factors on the different activities of NK cells. Understanding the effects of neuroendocrine factors on NK cell activities during physiological and pathophysiological conditions may result in novel therapeutic strategies to enhance NK cell functions against tumors.

Impairments in the reproductive axis of female mice lacking estrogen receptor ß in GnRH neurons.

The effect of estrogen on the differentiation and maintenance of reproductive tissues is mediated by two nuclear estrogen receptors (ERs), ERα, and ERß. Lack of functional ERα and ERß genes in vivo significantly affects reproductive function; however, the target tissues and signaling pathways in the hypothalamus are not clearly defined. Here, we describe the generation and reproductive characterization of a complete-ERß KO (CERßKO) and a GnRH neuron-specific ERßKO (GERßKO) mouse models. Both ERßKO mouse models displayed a delay in vaginal opening and first estrus. Hypothalamic gonadotropin-releasing hormone (GnRH) mRNA expression levels in both ERßKO mice were similar to control mice; however female CERßKO and GERßKO mice had lower basal and surge serum gonadotropin levels. Although a GnRH stimulation test in both female ERßKO models showed preserved gonadotropic function in the same animals, a kisspeptin stimulation test revealed an attenuated response by GnRH neurons, suggesting a role for ERß in normal GnRH neuron function. No alteration in estrogen-negative feedback was observed in either ERßKO mouse models after ovariectomy and estrogen replacement. Further, abnormal development of ovarian follicles with low serum estradiol levels and impairment of fertility were observed in both ERßKO mouse models. In male ERßKO mice, no differences in the timing of pubertal onset or serum luteinizing hormone and follicle-stimulating hormone levels were observed as compared with controls. Taken together, these data provide in vivo evidence for a role of ERß in GnRH neurons in modulating puberty and reproduction, specifically through kisspeptin responsiveness in the female hypothalamic-pituitary-gonadal axis.

α-MSH modulates cell adhesion and inflammatory responses of synovial fibroblasts from osteoarthritis patients.

INTRODUCTION: The synovium is a target for neuropeptides. Melanocortins have attained particular attention as they elicit antiinflammatory effects. Although synovial fluid from patients with rheumatic diseases contains α-melanocyte-stimulating hormone (α-MSH) it is unknown whether synovial fibroblasts generate α-MSH and respond to melanocortins. METHODS: Synovial tissue was obtained from osteoarthritis (OA) patients. Cells were isolated and prepared either as primary mixed synoviocytes or propagated as synovial fibroblasts (OASFs). Melanocortin receptor (MC) and proopiomelanocortin (POMC) expression were investigated by endpoint RT-PCR, immunofluorescence and Western immunoblotting. Functional coupling of MC1 was assessed by cAMP and Ca(2+) assays. Cell adhesion was monitored by the xCELLigence system. Secretion of α-MSH, tumour necrosis factor (TNF), interleukin (IL)-6 and IL-8 was determined by ELISA. RESULTS: OASFs in vitro expressed MC1. MC1 transcripts were present in synovial tissue and appropriate immunoreactivity was detected in synovial fibroblasts in situ. OASFs contained truncated POMC transcripts but neither full-length POMC mRNA, POMC protein nor α-MSH were detectable. In accordance with this only truncated POMC transcripts were present in synovial tissue. α-MSH increased cAMP dose-dependently but did not alter calcium in OASFs. α-MSH also enhanced adhesion of OASFs to fibronectin and reduced TNF, IL-6 and IL-8 secretion in primary mixed synoviocyte cultures. In OASFs, α-MSH modulated basal and TNF/IL-1ß-mediated secretion of IL-6 and IL-8. CONCLUSION: Synovial fibroblasts express MC1in vitro and in situ. α-MSH elicits biological effects in these cells suggesting an endogenous immunomodulatory role of melanocortins within the synovium. Our results encourage in vivo studies with melanocortins in OA models.

Anti-inflammatory effects of cell-based therapy with tyrosine hydroxylase-positive catecholaminergic cells in experimental arthritis.

OBJECTIVES: Studies in rheumatoid arthritis (RA), osteoarthritis (OA) and mice with arthritis demonstrated tyrosine hydroxylase-positive (TH(+)) cells in arthritic synovium and parallel loss of sympathetic nerve fibres. The exact function of TH(+) cells and mode of TH induction are not known. METHODS: Synovial cells of RA/OA were isolated and cultured under normoxic/hypoxic conditions with/without stimulating enzyme cofactors of TH and inhibitors of TH. We studied TH expression and release of cytokines/catecholamines. In vivo function was tested by cell therapy with TH(+) neuronal precursor cells (TH(+) neuronal cells) in DBA/1 mice with collagen type II-induced arthritis (CIA). RESULTS: Compared with normoxic conditions, hypoxia increased TH protein expression and catecholamine synthesis and decreased release of tumour necrosis factor (TNF) in OA/RA synovial cells. This inhibitory effect on TNF was reversed by TH inhibition with α-methyl-para-tyrosine (αMPT), which was particularly evident under hypoxic conditions. Incubation with specific TH cofactors (tetrahydrobiopterin and Fe(2+)) increased hypoxia-induced inhibition of TNF, which was also reversed by αMPT. To address a possible clinical role of TH(+) cells, murine TH(+) neuronal cells were generated from mesenchymal stem cells. TH(+) neuronal cells exhibited a typical catecholaminergic phenotype. Adoptive transfer of TH(+) neuronal cells markedly reduced CIA in mice, and 6-hydroxydopamine, which depletes TH(+) cells, reversed this effect. CONCLUSIONS: The anti-inflammatory effect of TH(+) neuronal cells on experimental arthritis has been presented for the first time. In RA/OA, TH(+) synovial cells have TH-dependent anti-inflammatory capacities, which are augmented under hypoxia. Using generated TH(+) neuronal cells might open new avenues for cell-based therapy.

Increased expression of dopamine receptors in synovial fibroblasts from patients with rheumatoid arthritis: inhibitory effects of dopamine on interleukin-8 and interleukin-6.

OBJECTIVE: Observations in both animal models of arthritis and patients with rheumatoid arthritis (RA) suggest a role for dopamine and its receptors in RA. Because synovial fibroblasts (SFs) contribute to inflammation and joint destruction in RA, the aim of this study was to investigate dopaminergic pathways in SFs obtained from patients with RA and, for comparison, in SFs from patients with osteoarthritis (OA) undergoing knee joint replacement surgery. METHODS: The expression of all dopamine receptors (D1 -D5 ) and dopamine transporter was assessed by immunofluorescence and immunohistochemical staining. The levels of dopamine receptor and tyrosine hydroxylase messenger RNA were measured by real-time polymerase chain reaction. The intracellular content of dopamine, its precursor, and its main metabolites was assayed by high-performance liquid chromatography. The influence of dopamine on proinflammatory interleukin-6 (IL-6) and IL-8, matrix metalloproteinase 3, and tissue inhibitor of metalloproteinases 1 (TIMP-1) and TIMP-2 was studied in SFs. RESULTS: SFs possess an intrinsic dopaminergic system, including dopamine receptors, dopamine transporter, and tyrosine hydroxylase, and contain dopamine, its precursor, and its main metabolites. SFs from patients with RA, in comparison with those from patients with OA, showed increased expression of dopamine receptors D1 and D5 , and exogenous dopamine strongly inhibited the production of IL-8 in patients with RA. CONCLUSION: SFs from patients with RA and patients with OA show a dopaminergic phenotype. The expression of D1-like dopamine receptors was higher in RASFs, and this increased expression may lead to antiinflammatory effects, as demonstrated by the expression of IL-8. Studies in animal models and patients with RA are needed to assess the therapeutic potential of endogenous, local production of dopamine in 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.

Intra-articular glucocorticoid injections decrease the number of steroid hormone receptor positive cells in synovial tissue of patients with persistent knee arthritis.

OBJECTIVES: To explore changes in the number of steroid hormone receptor positive cells in synovial tissue (ST) after intra-articular glucocorticoid injection, to correlate these changes with changes in clinical variables, and to evaluate whether the number of steroid hormone receptor positive cells predicted the clinical response to glucocorticoid injection. METHODS: Fourteen patients with persistent knee arthritis despite at least two previous injections in an outpatient setting received an intra-articular injection with glucocorticoids, followed by 3 days of admission with bed rest. Clinical efficacy was assessed at 6 and 12 weeks. ST biopsies were performed 2 weeks before and 12 weeks after the injection. The presence of different cell types (T cells, macrophages, fibroblast-like synoviocytes) and numbers of glucocorticoid, androgen and oestrogen α and ß receptor positive cells were evaluated by histochemistry. RESULTS: Patients showed, despite previous failures, good clinical response to glucocorticoid injection, with significant improvement in erythrocyte sedimentation rate, visual analogue scale (VAS) for pain, and joint disability score. The number of steroid hormone receptor positive cells decreased markedly (p<0.05 for all four receptors). The decrease in oestrogen receptor α positive cells correlated significantly with the improvement in VAS for pain and joint disability score. The number of glucocorticoid, androgen and oestrogen α and ß receptor positive cells before injection did not predict the effect of treatment. CONCLUSIONS: Intra-articular glucocorticoid injections followed by bed rest for persistent arthritis are clinically effective and significantly decrease the number of steroid hormone receptor positive cells in ST. The relevance of the latter needs further study.

Relationship between placenta growth factor 1 and vascularization, dehydroepiandrosterone sulfate to dehydroepiandrosterone conversion, or aromatase expression in patients with rheumatoid arthritis and patients with osteoarthritis.

OBJECTIVE: Proliferating pannus is in many aspects similar to placental tissue. Both fibroblast-rich tissues have high vascularity, and tissue from patients with rheumatoid arthritis (RA) and patients with osteoarthritis (OA) demonstrates conversion of androgenic prehormones to downstream estrogens. We undertook this study to investigate similarities between proliferating pannus and placental tissue by focusing on angiogenic placenta growth factor 1 (PlGF-1) in patients with OA and patients with RA. METHODS: We used immunohistochemistry to study the presence of PlGF-1, its synovial distribution, and the PlGF-1-expressing synovial cell type. The relationship between PlGF-1 and conversion of the biologically inactive placental prehormone dehydroepiandrosterone sulfate (DHEAS) to the biologically active dehydroepiandrosterone (DHEA) was investigated in mixed synovial cells. The effects of DHEA on PlGF-1 expression were studied by intracellular fluorescence-activated cell sorting analysis. RESULTS: PlGF-1-positive cells were detected in the lining and sublining areas in patients with RA and patients with OA, and cellular density was similar. Double staining revealed that PlGF-1-positive cells were macrophages. In RA and OA, the density of PlGF-1-positive cells correlated positively with the density of macrophages and the density of type IV collagen-positive vessels. The supernatant concentration of (3) H-DHEA after conversion from (3) H-DHEAS and the density of aromatase-positive cells were positively correlated with the density of PlGF-1-positive cells only in OA. Low DHEA concentrations (≤10(-9) M) had stimulatory effects on PlGF-1 when compared to serum concentrations (10(-8) M to 10(-7) M) in the monocytic cell line THP-1 and in primary mixed synovial cells. CONCLUSION: PlGF-1 functions similarly in inflamed synovium and in the placenta. It is related to vessel formation and, in OA patients, to androgen/estrogen conversion. Evolutionarily conserved functions of PlGF-1 for placental phenomena are obviously also present in synovial inflammation.

Loss of sympathetic nerve fibers in intestinal endometriosis.

This study analyzed by immunofluorescence staining the sympathetic innervation in the bowel adjacent to the endometriotic lesion and in the healthy tissue at the border of the resected specimen. Sympathetic nerve fibers are significantly reduced in the mucosal and muscular layer near the endometriotic lesions; in contrast, sensory nerve fiber density is not altered in the area near the endometriotic lesions.

Catecholamine-producing cells in the synovial tissue during arthritis: modulation of sympathetic neurotransmitters as new therapeutic target.

BACKGROUND: The proinflammatory and anti-inflammatory role of the sympathetic nervous system in early and late inflammation is an unresolved paradox. A drastic loss of sympathetic nerve fibres in the synovial tissue of patients with rheumatoid arthritis (RA) has previously been demonstrated. The presence of tyrosine hydroxylase (TH)-positive cells in RA and osteoarthritis (OA) has been determined, but the role of these cells in inflammation is still unclear. OBJECTIVE: To characterise TH-positive cells in inflamed RA and OA synovial tissue and to study their role in inflammation. METHODS: Synovial samples were obtained from 32 patients with OA and 19 patients with RA and from 10 control patients. Synovial tissue samples were used for immunofluorescence staining. Synovial cells were isolated by tissue digestion and immediately used for cell culture. For in vivo experiments, collagen type-II arthritis in DBA/1J mice was induced. RESULTS: TH+ cells were present only in inflamed tissue and not in controls. Catecholamine-storing vesicles and vesicular monoamine transporter 2 (VMAT2) were identified in the synovial tissue. Experimental increase of cytoplasmic catecholamines by VMAT2 blockade strongly reduced tumour necrosis factor (TNF) independently of canonical extracellular ß-adrenergic signalling. In addition, VMAT2 blockade increased cyclic AMP (cAMP) and cAMP responsive element binding protein, responsible for TNF inhibition. In vivo, appearance of VMAT2 positive cells was confirmed. VMAT2 blockade ameliorated inflammation also in vivo. CONCLUSIONS: This study demonstrates that local catecholamine-producing cells start to replace sympathetic nerve fibres around the onset of disease, and modulation of locally produced catecholamines has strong anti-inflammatory effects in vivo and in vitro.

Low density of sympathetic nerve fibers relative to substance P-positive nerve fibers in lesional skin of chronic pruritus and prurigo nodularis.

BACKGROUND: In prurigo nodularis (PN), an increase in the density of dermal substance P-positive (SP+) sensory nerve fibers has been demonstrated. In addition, the density of sympathetic nerve fibers is unchanged. OBJECTIVE: We aimed to investigate the density and balance of sensory and sympathetic dermal nerves in pruritus on normally appearing skin in comparison to PN. METHODS: In a parallel investigation in lesional and non-lesional skin routine histological and immunofluorescence staining against SP and tyrosine hydroxylase (TH) were performed. RESULTS: We found an increased density of dermal SP+ nerve fibers in PN and also in pruritus relative to sympathetic nerve fibers in affected areas compared to the unaffected site. The density of SP+ and TH+ nerves did not correlate with clinical parameters such as itch quality, duration or intensity. Sparse lymphocytic infiltration as found in affected pruritus skin may be a source of nerve growth factor and explain the hyperinnervation. CONCLUSION: Similar to the situation in PN, chronic pruritus lesions also demonstrate a preponderance of SP+ sensory nerve fibers relative to sympathetic nerve fibers, which probably acts as a causal pro-inflammatory signal in development of pruritus. These findings suggest new therapeutic approaches in patients with chronic pruritus.

The immunomodulatory effects of estrogens: clinical relevance in immune-mediated rheumatic diseases.

Immunological, epidemiological, and clinical evidence suggest that female sex hormones play an important role in the etiology and pathophysiology of chronic immune/inflammatory diseases. Several significant factors generate confusion and opposite conclusions in evaluating the role of estrogens in these diseases, including relatively superficial translational studies from animals to the human condition, the different effects of estrogens on their different receptors or on different target cells, the different estrogen concentrations employed, and opposite effects (especially on cell proliferation) exerted by different peripheral estrogen metabolites. A preponderance of 16alpha-hydroxylated estrogens, as observed in rheumatoid arthritis synovial fluids, is an unfavorable sign in synovial inflammation. Since 17beta-estradiol administered during hormone replacement therapy will rapidly increase estrone sulfate after conversion in adipose tissue by aromatases, hormone replacement therapy can have proinflammatory effects by providing estrone sulfate to the inflamed synovial tissue. In addition, it appears that the use of combined oral contraceptives is associated with an increased risk of at least systemic lupus erythematosus. In conclusion, estrogens are generally considered as enhancers of cell proliferation and humoral immune response.

Estrone/17beta-estradiol conversion to, and tumor necrosis factor inhibition by, estrogen metabolites in synovial cells of patients with rheumatoid arthritis and patients with osteoarthritis.

OBJECTIVE: The role of estrogens in rheumatoid arthritis (RA) is debated since both proinflammatory and antiinflammatory effects have been reported. Important evidence of the dual role of estrogens is conversion to various proinflammatory or antiinflammatory metabolites. This study was undertaken to examine the downstream conversion of estrogens in synovial cells from patients with RA or osteoarthritis (OA). METHODS: We studied serum levels of estrone, estrone sulfate, and estrone sulfate membrane transporters, intracellular interconversion of estrone and 17beta-estradiol, and conversion of estrone/17beta-estradiol to various estrogen metabolites in RA and OA synovial cells. The effect of estrogen metabolites on tumor necrosis factor (TNF) secretion was also studied in RA and OA synovial cells. RESULTS: Serum levels of estrone sulfate were similar in healthy controls and RA patients. Estrone sulfate transporters were present in synovial tissue. Interconversion of estrone and 17beta-estradiol and the expression of converting enzymes of the cytochrome P450 family were similar in RA and OA cells. Using estrone and 17beta-estradiol as substrates, RA and OA synovial cells produced 16alpha-, 4-, and 2-hydroxylated estrogens and their 4- and 2-methylation products. The levels of 16alpha-hydroxylated estrone/17beta-estradiol (16alphaOH-estrone/16alphaOH-17beta-estradiol) were higher than the levels of all other estrogen metabolites. RA synovial cells produced more 16alphaOH-estrone than did OA synovial cells. Importantly, the 16alphaOH estrogens did not inhibit TNF secretion, whereas all other estrogen metabolites had marked inhibitory effects. CONCLUSION: Our findings indicate that precursor estrogens are converted to proinflammatory metabolites, particularly in RA synovial cells. RA synovial cells mainly produce the proproliferative 16alphaOH-estrone, which, in addition to 16alphaOH-17beta-estradiol, is one of the only 2 estrogens studied that does not inhibit TNF secretion. A preponderance of 16alpha-hydroxylated estrogens is an unfavorable sign in synovial inflammation.

Neuroendocrine immune pathways in chronic arthritis.

The analysis and understanding of the complex effects of endocrine and nervous system alterations on the inflammatory process in human arthritis is far from complete. Such alterations are observed as decreased responsiveness of the hypothalamic-pituitary-adrenal axis, an inadequate production of cortisol in relation to inflammation, and - consequently - elevated sympathetic activity, alterations of sex hormone metabolism (loss of androgens), psychological alterations (with chronic fatigue and symptoms of depression due to elevated circulating cytokines), local reduction of synovial sympathetic innervation, altered metabolism of estrogens in the synovium, and high expression of estrogen receptors in synovial cells. An understanding of these alterations will help to identify the different neuroendocrine immune mechanisms involved in the pathophysiology of rheumatoid arthritis and could trigger research into novel therapeutic targets for the treatment of patients with rheumatoid arthritis.

Peritoneal fluid macrophages in endometriosis: correlation between the expression of estrogen receptors and inflammation.

OBJECTIVE: To investigate the expression of estrogen receptors (ERs) and inflammatory cytokines in macrophages obtained from peritoneal fluid (PF) of women with endometriosis. DESIGN: Comparative immunocytochemical study. SETTING: University hospital. PATIENT(S): Thirty women with endometriosis and 22 controls. INTERVENTION(S): The PF samples were collected at laparoscopy. MAIN OUTCOME MEASURE(S): The expression of ERalpha, ERbeta, differentiation markers (CD68, NCL-MACRO, HAM56), and inflammatory cytokines (interleukin [IL]-1beta, tumor necrosis factor-alpha [TNF-alpha], IL-6) in PF macrophages was determined. RESULT(S): The expression of CD68, NCL-MACRO, HAM56, TNFalpha, IL-6, and IL-1beta was significantly higher in PF macrophages obtained from women with endometriosis than in controls. The ERalpha and ERbeta had significantly higher expression in macrophages of women with endometriosis than in controls. A positive correlation was observed between the expression of ERalpha and ERbeta both in women with and without endometriosis. The ERalpha expression was positively correlated with the expression of inflammatory cytokines in women with endometriosis but not in controls; ERbeta expression was correlated to the expression of inflammatory cytokines in the both groups. CONCLUSION(S): There is a correlation between the expression of ERbeta and proinflammatory cytokines both in women with and without endometriosis. The expression of ERalpha correlates with cytokine production selectively in women with endometriosis but not in controls.

Effects of testosterone, 17beta-estradiol, and downstream estrogens on cytokine secretion from human leukocytes in the presence and absence of cortisol.

Estrogens at physiological concentrations are thought to play an immune-stimulating role, whereas androgens have an anti-inflammatory impact. However, their role on cytokine secretion in the presence or absence of cortisol has not been investigated. Furthermore, the role of hydroxylated estrogens downstream of 17beta-estradiol (E2) on secretion of tumor necrosis factor (TNF) is not known. In this study on peripheral blood leukocytes of healthy male subjects, we scrutinized the influence of prior sex hormones (for 24 h) with and without later addition of cortisol (for another 24 h) on stimulated secretion of TNF, IL-2, IL-4, IL-6, IL-10, and interferon-gamma (IFN-gamma). E2 stabilized or increased immune stimuli-induced secretion of TNF, IL-2, IL-4, IL-6, IL-10, and IFNgamma in relation to testosterone. Testosterone, in contrast, inhibited (IL-2, IL-4, IL-10) or tended to inhibit stimulated secretion of these cytokines (TNF, IFNgamma). This effect of E2 was pronounced at a concentration of 10(-10) M (testosterone: 10(-7) M) in the presence of cortisol. E2 (10(-8) M, 10(-10) M) and testosterone (10(-7) M) did not change glucocorticoid receptor expression. The downstream estrogens 2OH-estradiol(one), 4OH-estradiol(one), and 16OH-estradiol(one) did not stimulate TNF secretion at 10(-10) M, but even inhibited its secretion at 10(-11) M. However, the combination of 16OH-estradiol(one) on one side and 2OH-estradiol(one) or 4OH-estradiol(one) on the other side markedly stimulated TNF secretion that was only observable in the presence of cortisol. In conclusion, at physiological concentrations, E2 and a combination of downstream estrogens stabilized or increased immune stimuli-induced TNF secretion. These effects are dependent on the presence of physiological concentrations of cortisol. This study underlines the proinflammatory role of E2, which is probably dependent on conversion to a proinflammatory cocktail of downstream estrogens and the presence of cortisol.

Role of estrogens in inflammatory response: expression of estrogen receptors in peritoneal fluid macrophages from endometriosis.

Estrogens are involved in the immune response, and macrophages express estrogen receptors (ER). Moreover, macrophages are the predominant cell type in the peritoneal fluid from endometriosis patients. On this basis, the aim of our study was to evaluate the expression of ER on peritoneal macrophages from endometriosis patients and to compare these results with what is already known about ER and macrophages in RA. After macrophage extraction from peritoneal fluids we performed the immunohistochemical localization of ERalpha and ERbeta and then the image analysis. We found that both ERs were significantly overexpressed in macrophages of women with endometriosis compared with controls. These results suggest that estrogens, through their functional receptors, might modulate the immune response at least on macrophages. Therefore, estrogens seem to play an important role in the immune response, independently from the pathology.

Glucocorticoid effects on adrenal steroids and cytokine responsiveness in polymyalgia rheumatica and elderly onset rheumatoid arthritis.

Polymyalgia rheumatica (PMR) usually exhibits a good clinical response to glucocorticoid (GC) treatment, but early clinical symptoms may create some difficulties in the differential diagnosis with elderly onset rheumatoid arthritis (EORA), particularly in patients complaining of shoulder and pelvic girdle involvement at onset (PMR-like clinical onset) (EORA/PMR). Since neuroendocrine mechanisms seem to play a pathogenetic role in these clinical conditions, the aim of this study was to evaluate hormone and cytokine responsiveness to GC treatment in these patients. Cortisol (CO), dehydroepiandrosterone sulphate (DHEAS), 17-OH-progesterone (PRG), interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) were evaluated at base line, and 1 month after GC treatment (prednisone 10 mg/day), in 14 PMR, 11 EORA/PMR, and 13 EORA patients (mean age 73 +/- 5 years, +/- SD, mean disease duration 3 +/- 2 months, +/- SD). No patient was taking GCs or immunosuppressive agents at base line. Following GC treatment, CO, DHEAS, and PRG decreased significantly in both PMR and EORA/PMR patients (P < 0.05), but not in EORA patients. On the contrary, IL-1Ra was significantly increased in both PMR and EORA/PMR patients (P < 0.05). IL-6 and TNF-alpha serum levels were significantly decreased in all groups of patients (P < 0.05). In conclusion, PMR and EORA/PMR seem to exhibit similar hormonal variations after GC administration, when compared to EORA patients. These differences suggest a deficient function of the hypothalamic-pituitary-adrenal (HPA) axis in PMR and EORA/PMR patients, with a related higher responsiveness to GC treatment. Interestingly, in PMR and EORA/PMR patients, GC treatment was found to downregulate PRG serum levels.

Anti-TNF and sex hormones.

Whenever serum estrogen concentrations are normal in rheumatoid arthritis (RA) patients, lower androgen concentrations (i.e., testosterone, androstenedione, and dehydroepiandrosterone sulfate [DHEAS]) are detected in the serum as well as in the synovial fluid of male and female RA patients. The presence in the RA synovial fluid of a significant altered sex hormone balance resulting in lower immunosuppressive androgens and higher immuno-enhancing estrogens, might determine a favorable condition for the development of the immunomediated RA synovitis. The inflammatory cytokines (i.e., TNF-alpha), particularly increased in RA synovitis, are able to markedly stimulate the aromatase activity in peripheral tissues and, therefore, induce the peripheral metabolism from androgens to estrogens. The effects of TNF blockers (and generally of anticytokine agents) on peripheral sex hormone levels seem exerted in a faster way at the level of the RA synovial tissue (before any influence on serum levels) where they seem to block the conversion from androgens (anti-inflammatory) to estrogens (proinflammatory) induced by aromatase. Therefore, the beneficial effects of restoring synovial androgens might be clinically more evident in male RA patients (as recently observed in ANTARES study) since they suffer more for the lack of androgens (anti-inflammatory) on account of the action of TNF-alpha on peripheral hormonal conversion. However, therapy (3 months) with anti-TNF did not change serum levels of typical sex hormones in patients with RA, although baseline values were largely different from controls. In patients with at least long-standing RA, this indicates that alterations of serum sex hormones and altered activity of respective converting enzymes are imprinted for a long-lasting period over at least 12 weeks.

Estrogens and autoimmune diseases.

Sex hormones are implicated in the immune response, with estrogens as enhancers at least of the humoral immunity and androgens and progesterone (and glucocorticoids) as natural immune-suppressors . Several physiological, pathological, and therapeutic conditions may change the serum estrogen milieu and/or peripheral conversion rate, including the menstrual cycle, pregnancy, postpartum period, menopause, being elderly, chronic stress, altered circadian rhythms, inflammatory cytokines, and use of corticosteroids, oral contraceptives, and steroid hormonal replacements, inducing altered androgen/estrogen ratios and related effects. In particular, cortisol and melatonin circadian rhythms are altered, at least in rheumatoid arthritis (RA), and partially involve sex hormone circadian synthesis and levels as well. Abnormal regulation of aromatase activity (i.e., increased activity) by inflammatory cytokine production (i.e., TNF-alpha, IL-1, and IL-6) may partially explain the abnormalities of peripheral estrogen synthesis in RA (i.e., increased availability of 17-beta estradiol and possible metabolites in synovial fluids) and in systemic lupus erythematosus, as well as the altered serum sex-hormone levels and ratio (i.e., decreased androgens and DHEAS). In the synovial fluids of RA patients, the increased estrogen concentration is observed in both sexes and is more specifically characterized by the hydroxylated forms, in particular 16alpha-hydroxyestrone, which is a mitogenic and cell proliferative endogenous hormone. Local effects of sex hormones in autoimmune rheumatic diseases seems to consist mainly in modulation of cell proliferation and cytokine production (i.e., TNF-alpha, Il-1, IL-12). In this respect, it is interesting that male patients with RA seem to profit more from anti-TNFalpha strategies than do female patients.