Integrated neuroendocrine immune risk factors in relation to rheumatoid arthritis: should rheumatologists now adopt a model of a multiyear, presymptomatic phase?

Contribution of Genetic Factors to Lower DHEAS in Patients with Rheumatoid Arthritis

OBJECTIVE

Lower production of adrenal androgens has been confirmed in females with rheumatoid arthritis (RA); however, the mechanisms of this finding are not completely understood. The aim of our study was to assess the contribution of genetic factors associated with variability of dehydroepiandrosterone sulfate (DHEAS) levels to lower DHEAS in female RA patients.

METHODS

448 RA and 648 healthy controls were genotyped for single-nucleotide polymorphisms (SNPs) in genes ZKSCAN5 (rs11761528), SULT2A1 (rs2637125), HHEX (rs2497306), and ARPC1A (rs740160). Serum DHEAS concentrations were measured in 112 RA patients and 91 healthy women.

RESULTS

The allele frequencies in DHEAS-related loci were similar in RA and controls. RA patients had significantly lower serum DHEAS concentrations compared to healthy women. The cumulative number of alleles associated with lower DHEAS within genes ZKSCAN5, SULT2A1, HHEX, and ARPC1A present in each individual negatively correlated with DHEAS levels in RA patients, but not in controls. Linear regression analysis showed significant effect of polymorphisms in genes ZKSCAN5 and ARPC1A on serum DHEAS levels in female RA patients but not in the control group.

CONCLUSION

Our findings suggest that complex interactions exist between genotype and adrenal androgen hypofunction in RA.

Hypothalamic-Pituitary-Adrenal Hypofunction in Myalgic Encephalomyelitis (ME)/Chronic Fatigue Syndrome (CFS) as a Consequence of Activated Immune-Inflammatory and Oxidative and Nitrosative Pathways

There is evidence that immune-inflammatory and oxidative and nitrosative stress (O&NS) pathways play a role in the pathophysiology of myalgic encephalomyelitis (ME)/chronic fatigue syndrome (CFS). There is also evidence that these neuroimmune diseases are accompanied by hypothalamic-pituitary-adrenal (HPA) axis hypoactivity as indicated by lowered baseline glucocorticoid levels. This paper aims to review the bidirectional communications between immune-inflammatory and O&NS pathways and HPA axis hypoactivity in ME/CFS, considering two possibilities: (a) Activation of immune-inflammatory pathways is secondary to HPA axis hypofunction via attenuated negative feedback mechanisms, or (b) chronic activated immune-inflammatory and O&NS pathways play a causative role in HPA axis hypoactivity. Electronic databases, i.e., PUBMED, Scopus, and Google Scholar, were used as sources for this narrative review by using keywords CFS, ME, cortisol, ACTH, CRH, HPA axis, glucocorticoid receptor, cytokines, immune, immunity, inflammation, and O&NS. Findings show that activation of immune-inflammatory and O&NS pathways in ME/CFS are probably not secondary to HPA axis hypoactivity and that activation of these pathways may underpin HPA axis hypofunction in ME/CFS. Mechanistic explanations comprise increased levels of tumor necrosis factor-α, T regulatory responses with elevated levels of interleukin-10 and transforming growth factor-β, elevated levels of nitric oxide, and viral/bacterial-mediated mechanisms. HPA axis hypoactivity in ME/CFS is most likely a consequence and not a cause of a wide variety of activated immune-inflammatory and O&NS pathways in that illness.

Sexual Dimorphisms of Adrenal Steroids, Sex Hormones, and Immunological Biomarkers and Possible Risk Factors for Developing Rheumatoid Arthritis

Innate immunity and immunological biomarkers are believed to be interrelated with sex hormones and other neuroendocrine factors. Sexual dimorphism mechanisms may be operating in certain rheumatic and inflammatory diseases which occur more frequently in women than men, as rheumatoid arthritis (RA). Less data have been available on altered interrelations of the combined neuroendocrine and immune (NEI) systems as risk factors for development of certain diseases. In this study, serological interrelations of NEI biomarkers are analyzed before symptomatic onset of RA (pre-RA) versus control (CN) subjects, stratified by sex. Sexual dimorphism was found in serum levels of acute serum amyloid A (ASAA), soluble interleukin-2 receptor alpha (sIL-2Rα), and soluble tumor necrosis factor receptor 1 (sTNF-R1). Multiple steroidal and hormonal (neuroendocrine) factors also showed highly (p < 0.001) significant sexual dimorphism in their assayed values, but less for cortisol (p = 0.012), and not for 17-hydroxyprogesterone (p = 0.176). After stratification by sex and risk of developing RA, differential NEI correlational patterns were observed in the interplay of the NEI systems between the pre-RA and CN groups, which deserve further investigation.

Determinants of adrenal androgen hypofunction in premenopausal females with rheumatoid arthritis

The aim of our study was to investigate adrenocortical function in the context of disease activity and inflammatory status in premenopausal RA females. Adrenal glucocorticoid and androgen responses to the 1 microg ACTH 1-24 test were investigated in 23 premenopausal RA and in 15 age- and BMI-matched healthy females. Twelve RA patients were on low-dose prednisone (<8.5 mg/day). Patients with DAS28>3.2 had lower (p<0.05) total plasma cortisol, 17-hydroxyprogesterone, dehydroepiandrosterone and androstenedione responses in the ACTH test compared to healthy controls. Patients with DAS28>3.2 had lower (p<0.05) dehydroepiandrosterone response in the ACTH test compared to patients with DAS28</=3.2. C-reactive protein (CRP), DAS28, and interleukin (IL)-6 negatively correlated with androstenedione response to ACTH 1-24. Responses of all measured adrenal steroids were lower (p<0.05) in patients on low-dose glucocorticoids compared to healthy controls. RA patients not treated with glucocorticoids had lower total cortisol response (p=0.038) but did not differ in free plasma cortisol in the ACTH test. The results indicate an association of increased disease activity with a decrease in adrenal androgen production in RA and normal cortisol bioavailability in patients not treated with glucocorticoids.

Controlled Cohort Study of Serum Gonadal and Adrenocortical Steroid Levels in Males Prior to Onset of Rheumatoid Arthritis (pre-RA): A Comparison to pre-RA Females and Sex Differences among the Study Groups

Serum testosterone levels are generally reported to be lower in male rheumatoid arthritis (RA) patients, but it is not determined if a deficiency may occur before clinical onset of disease (pre-RA). Lower testosterone levels were recently reported in males many years before RA onset but were predictive only of rheumatoid factor (RF)—negative disease. A preceding prospective study did not reveal androgenic-anabolic hormone association with risk of RA in men or women. This cohort study of males analyzed baseline serum levels of gonadal and adrenocortical steroids, luteinizing hormone, and prolactin in 18 pre-RA versus 72 matched non-RA control (CN) subjects. Findings in males were compared to those in female pre-RA and CN subjects in the same cohort, and sex differences were analyzed. Steroidal and hormonal levels, including total testosterone, were similar between male study groups. In females, mean (±SE) serum androstenedione (nmol/L) was slightly (P = 0.048) lower in 36 pre-RA (6.7 ± 0.36) than 144 CN (7.6 ± 0.22). With the exception of 3 partial correlations of hormonal variables observed to differ between pre-RA versus CN subjects, the patterns were similar overall. However, partial correlations of hormonal variables differed frequently by sex, both within and between study groups.

Serum acute phase protein and inflammatory cytokine network correlations: comparison of a pre-rheumatoid arthritis and non-rheumatoid arthritis community cohort

Serum concentrations of acute phase proteins, inflammatory cytokines, and other immunological components were individually assayed using high-sensitivity ELISA in a com-munity-based cohort of preclinical rheumatoid arthritis (pre-RA) and matched non-RA control (CN) subjects. Bivariate correlations of the biomarker panel concentrations were compared in pre-RA versus CN and female versus male subjects. Clinically elevated CRP levels (8+ mg/l) occurred in a higher (p = 0.010) frequency in 46 pre-RA (n = 8, 17.4%) subjects than in 179 CN (n = 9, 5.0%), and were independent of age, gender, smoking behaviors, and serum rheumatoid factor. Selected age and gender differences were found in levels of the immunological network factors. In each study group, the ratio of sTNF-RI to IL-2sRα mean concentrations was 2-fold higher in men than in women. Aging correlated positively with CRP, ASAA, and TNF-α levels, but negatively with IL-1β. Bivariate correlations were similar in pre-RA subjects versus CN and by gender, with few exceptions. Factor loadings in principal component analysis of the total subjects indicated that age- and gender-related variables constituted the two main components. Using multiple regression analyses, an integrative working model of all variable interrelations was generated. The tentative, directional model supports a concept of gender dimorphism of the ratio of sTNF-RI to IL-2sRα serum concentrations and displays differing effects of age on TNF-α versus IL-1β levels. These findings indicate complex age, gender, and cytokine interrelations in control of the immune systems network. Future research in testing such inflammatory pathways promises a better understanding of predisposition to diseases, like RA.

Hypothalamic-pituitary-adrenal axis in rheumatoid arthritis

The controlled data accumulated so far support only subtle alterations in HPA axis function in RA, mainly at the adrenal level, and particularly in a subset of premenopausal-onset women. Such interpretation is supported by consistent findings of lower levels of adrenal androgens, particularly DHEAS, in premenopausal-onset RA patients. Consequences of the subtle HPA alterations in RA for the disease development remain unclear. From a broader perspective, the unresponsiveness of the HPA axis to chronic inflammation in RA simply can be seen as an ongoing adaptation to the disease state with higher priority to proper regulation of core body functions over the immune homeostasis.

Why are women predisposed to autoimmune rheumatic diseases?

The majority of autoimmune diseases predominate in females. In searching for an explanation for this female excess, most attention has focused on hormonal changes - both exogenous changes (for example, oral contraceptive pill) and fluctuations in endogenous hormone levels particularly related to menstruation and pregnancy history. Other reasons include genetic differences, both direct (influence of genes on sex chromosomes) and indirect (such as microchimerism), as well as gender differences in lifestyle factors. These will all be reviewed, focusing on the major autoimmune connective tissue disorders: rheumatoid arthritis, systemic lupus erythematosus and scleroderma.

Sex Hormones and Risks of Rheumatoid Arthritis and Developmental or Environmental Influences

Sex hormone relationships for onset risks of rheumatoid arthritis (RA) were analyzed in a nested case-control study, derived from a large community-based prospective cohort. A self-reported history of RA in a first-degree relative, heavy cigarette smoking, and positive rheumatoid factor (RF) were confirmed predictors of subsequent RA onset in this data set. In the 11 premenopausal onset cases, lower serum dehydroepiandrosterone sulfate levels were observed as was an imbalance in serum IL-1beta to IL-1ra levels; the latter was not observed in the 43 controls (CNs). In the 18 male cases, significantly higher serum cortisol was observed in the six cases with positive family history versus the 12 with a negative history. To the contrary, a small minority of the male cases had combined low serum cortisol and testosterone, which was not observed in the 72 CNs. Significant gender dimorphism was observed between the sex hormones and serum log RF titers as well as in the correlations of serum log testosterone and estradiol. Principal component analysis of multiply-imputed data sets extracted four uncorrelated components, which provided concordant neuroendocrine immune relationships to the previously investigated univariate and multivariate analyses. The literature on developmental and environmental influences on sex hormones and risks of RA was reviewed.