Low levels of dehydroepiandrosterone sulphate in plasma, and reduced sympathoadrenal response to hypoglycaemia in premenopausal women with rheumatoid arthritis

Exosomal hsa-miR-335-5p and hsa-miR-483-5p are novel biomarkers for rheumatoid arthritis: A development and validation study

BACKGROUND

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes cartilage and bone damage. Exosomes are small extracellular vesicles that play a critical role in intercellular communication and various biological processes by serving as vehicles for the transfer of diverse molecules, such as nucleic acids, proteins, and lipids, between cells. The purpose of this study was to develop potential biomarkers for RA in peripheral blood by performing small non-coding RNA (sncRNA) sequencing using circulating exosomes from healthy controls and patients with RA.

METHODS

In this study, we investigated extracellular sncRNAs associated with RA in peripheral blood. Using RNA sequencing and differentially expressed sncRNA analysis, we identified a miRNA signature and target genes. Target gene expression was validated via the four GEO datasets.

RESULTS

Exosomal RNAs were successfully isolated from the peripheral blood of 13 patients with RA and 10 healthy controls. The hsa-miR-335-5p and hsa-miR-486-5p expression levels were higher in patients with RA than in controls. We identified the SRSF4 gene, which is a common target of hsa-miR-335-5p and hsa-miR-483-5p. As expected, the expression of this gene was found to be decreased in the synovial tissues of patients with RA through external validation. In addition, hsa-miR-335-5p was positively correlated with antiCCP, DAS28ESR, DAS28CRP, and rheumatoid factor.

CONCLUSIONS

Our results provide strong evidence that circulating exosomal miRNA (hsa-miR-335-5p and hsa-miR-486-5p) and SRSF4 could be valuable biomarkers for RA.

Interplay of Environmental, Individual and Genetic Factors in Rheumatoid Arthritis Provocation

In this review, we explore systemization of knowledge about the triggering effects of non-genetic factors in pathogenic mechanisms that contribute to the development of rheumatoid arthritis (RA). Possible mechanisms involving environmental and individual factors in RA pathogenesis were analyzed, namely, infections, mental stress, sleep deprivation ecology, age, perinatal and gender factors, eating habits, obesity and smoking. The non-genetic factors modulate basic processes in the body with the impact of these factors being non-specific, but these common challenges may be decisive for advancement of the disease in the predisposed body at risk for RA. The provocation of this particular disease is associated with the presence of congenital loci minoris resistentia. The more frequent non-genetic factors form tangles of interdependent relationships and, thereby, several interdependent external factors hit one vulnerable basic process at once, either provoking or reinforcing each other. Understanding the specific mechanisms by which environmental and individual factors impact an individual under RA risk in the preclinical stages can contribute to early disease diagnosis and, if the factor is modifiable, might be useful for the prevention or delay of its development.

Adrenocortical dysfunction in rheumatoid arthritis: Α narrative review and future directions

BACKGROUND

Iatrogenic adrenal insufficiency (AI) secondary to long-term treatment with exogenous glucocorticoids (GC) is common in patients with systematic rheumatic diseases, including rheumatoid arthritis (RA). Moreover, a proportion of these patients is always in need of even small doses of glucocorticoids to maintain clinical remission, despite concomitant treatment with conventional and biologic disease-modifying drugs.

METHODS

We conducted a literature review up to December 2020 on (a) the incidence of AI in both long-term GC-treated and GC-treatment naïve RA patients; (b) the potential effects of increased levels of circulating proinflammatory cytokines, as well as of chronic stress, in adrenocortical function in RA; (c) the circadian cortisol rhythm in RA; and (d) established and evolving methods of assessment of adrenocortical function.

RESULTS

Up to 48% of RA patients develop glucocorticoid-induced AI; however, predictors are not established, while adrenocortical dysfunction may also occur in GC-treatment naïve RA patients. Experimental and clinical data have suggested that inadequate production of endogenous cortisol relative to enhanced clinical needs associated with the systemic inflammatory response, coined as the 'disproportion principle', may operate in RA. Although the underlying mechanisms are unknown, both proinflammatory cytokines and chronic stress may contribute the most in the adrenals hyporesponsiveness and the target tissue glucocorticoid resistance that have been described, but not systematically studied. A precise longitudinal assessment of endogenous cortisol production may be needed for optimal RA management.

CONCLUSION

Apart from iatrogenic AI, an intrinsically compromised adrenal reserve in RA may have a pathogenetic role and interfere with effective management, thus deserving further research.

Effects of dehydroepiandrosterone on quality of life in premenopausal women with rheumatoid arthritis: A preliminary randomized clinical trial

AIM

Chronic inflammation and subsequent use of glucocorticoids can lead to relative adrenocortical insufficiency in patients with rheumatoid arthritis (RA). Previously, adrenocortical hormone, dehydroepiandrosterone (DHEA) was shown as a potential therapy for autoimmune disorders. However, data regarding effects of DHEA in RA are limited. The aim of this study was to investigate the effects of DHEA on quality of life (QOL) in premenopausal rheumatoid arthritis patients.

METHOD

In this randomized double blinded, controlled trial 46 premenopausal rheumatoid arthritis patients were assigned to receive 50 mg/d DHEA (23 patients) or placebo (23 patients) for 12 weeks. Disease Activity Score of 28 joints - erythrocyte sedimentation rate (DAS28-ESR) questionnaire, visual analog score and swollen and tender joint counts (both 0-28) were used for assessment of disease activity. Persian-validated World Health Organization Quality of Life Brief version (WHOQOL BREF) questionnaire was used to assess quality of life.

RESULTS

In comparison to the control group more improvement in QOL (P = .025) and environment health (P = .001) was observed in the DHEA group. After adjustment for age and disease duration DHEA was associated with more improvement in QOL (P = .01), psychological (P = .02) and physical health (P = .03). A trend toward a decrease in ESR was observed in DHEA group (P = .06). DAS was improved in both groups; however, there was no significant change in DAS28 between groups (P = .88). Frequency of adverse events albeit minor was similar in both groups.

CONCLUSION

Our study supports a slightly superior effect of DHEA over placebo to improve QOL in premenopausal female patients with rheumatoid arthritis. We did not find improvement in DAS in the DHEA group over placebo.

A discovery of screening markers for rheumatoid arthritis by liquid chromatography mass spectrometry: A metabolomic approach

AIM

This study aimed to discover serum metabolite biomarkers for potential use in screening for rheumatoid arthritis (RA).

METHODS

The sera from 43 healthy controls (HCs) and 49 RA patients were globally analyzed using high-performance liquid chromatography- tandem mass spectrometry. Molecular features (MFs) from samples were analyzed using volcano plots, partial least squares discriminant analysis, and variable importance in projection scores to select candidates. The spectra of candidate MFs were matched with the METLIN database. We confirmed the association between candidates and RA and analyzed the receiver-operating characteristic (ROC) curves.

RESULTS

We selected a total of 57 candidate MFs that had a fold change ≥1.5, P value ≤.05, and over 80% of frequency. Among them, 18 MFs were identified as metabolites with the METLIN database. Six metabolites (dehydroepiandrosterone sulfate, androsterone sulfate, γ-linolenic acid, 9[E],11[E]-conjugated linoleic acid, docosahexaenoic acid, and docosapentaenoic acid [22n-3]) out of the 18 were associated with mechanisms of RA and were selected as final candidates. ROC curve analysis revealed their area under the curve (AUC) values were all above 0.75 and the combined AUC of the six candidates was 0.89.

CONCLUSION

Using six candidates as a marker set showed potential in distinguishing RA patients from HCs, based on high AUC values. Therefore, we propose that a marker set of these six candidates has potential clinical application in RA screening.

DHEA Inhibits Leukocyte Recruitment through Regulation of the Integrin Antagonist DEL-1

Leukocytes are rapidly recruited to sites of inflammation via interactions with the vascular endothelium. The steroid hormone dehydroepiandrosterone (DHEA) exerts anti-inflammatory properties; however, the underlying mechanisms are poorly understood. In this study, we show that an anti-inflammatory mechanism of DHEA involves the regulation of developmental endothelial locus 1 (DEL-1) expression. DEL-1 is a secreted homeostatic factor that inhibits β2-integrin-dependent leukocyte adhesion, and the subsequent leukocyte recruitment and its expression is downregulated upon inflammation. Similarly, DHEA inhibited leukocyte adhesion to the endothelium in venules of the inflamed mouse cremaster muscle. Importantly, in a model of lung inflammation, DHEA limited neutrophil recruitment in a DEL-1-dependent manner. Mechanistically, DHEA counteracted the inhibitory effect of inflammation on DEL-1 expression. Indeed, whereas TNF reduced DEL-1 expression and secretion in endothelial cells by diminishing C/EBPβ binding to the DEL-1 gene promoter, DHEA counteracted the inhibitory effect of TNF via activation of tropomyosin receptor kinase A (TRKA) and downstream PI3K/AKT signaling that restored C/EBPβ binding to the DEL-1 promoter. In conclusion, DHEA restrains neutrophil recruitment by reversing inflammation-induced downregulation of DEL-1 expression. Therefore, the anti-inflammatory DHEA/DEL-1 axis could be harnessed therapeutically in the context of inflammatory diseases.

Androgen-Induced Immunosuppression

In addition to determining biological sex, sex hormones are known to influence health and disease via regulation of immune cell activities and modulation of target-organ susceptibility to immune-mediated damage. Systemic autoimmune disorders, such as systemic lupus erythematosus, rheumatoid arthritis, and multiple sclerosis are more prevalent in females, while cancer shows the opposite pattern. Sex hormones have been repeatedly suggested to play a part in these biases. In this review, we will discuss how androgens and the expression of functional androgen receptor affect immune cells and how this may dampen or alter immune response(s) and affect autoimmune disease incidences and progression.

Potential approaches to prevent hypoglycemia-associated autonomic failure

Clear health benefits are associated with intensive glucose control in type 1 diabetes mellitus (T1DM). However, maintaining near-normal glycemia remains an elusive goal for many patients, in large part owing to the risk of severe hypoglycemia. In fact, recurrent episodes of hypoglycemia lead to 'hypoglycemia-associated autonomic failure' (HAAF), characterized by defective counter-regulatory responses to hypoglycemia. Extensive studies to understand the mechanisms underlying HAAF have revealed multiple potential etiologies, suggesting various approaches to prevent the development of HAAF. In this review, we present an overview of the literature focused on pharmacological approaches that may prevent the development of HAAF. The purported underlying mechanisms of HAAF include: 1) central mechanisms (opioid receptors, ATP-sensitive K+(KATP) channels, adrenergic receptors, serotonin selective receptor inhibitors, γ-aminobuyric acid receptors, N-methyl D-aspartate receptors); 2) hormones (cortisol, estrogen, dehydroepiandrosterone (DHEA) or DHEA sulfate, glucagon-like peptide-1) and 3) nutrients (fructose, free fatty acids, ketones), all of which have been studied vis-à-vis their ability to impact the development of HAAF. A careful review of the current literature reveals many promising therapeutic approaches to treat or reduce this important limitation to optimal glycemic control.

Large Scale Metabolic Profiling identifies Novel Steroids linked to Rheumatoid Arthritis

Recent metabolomics studies of Rheumatoid Arthritis (RA) reported few metabolites that were associated with the disease, either due to small cohort sizes or limited coverage of metabolic pathways. Our objective is to identify metabolites associated with RA and its cofounders using a new untargeted metabolomics platform. Moreover, to investigate the pathomechanism of RA by identifying correlations between RA-associated metabolites. 132 RA patients and 104 controls were analyzed for 927 metabolites. Metabolites were tested for association with RA using linear regression. OPLS-DA was used to discriminate RA patients from controls. Gaussian Graphical Models (GGMs) were used to identify correlated metabolites. 32 metabolites are identified as significantly (Bonferroni) associated with RA, including the previously reported metabolites as DHEAS, cortisol and androstenedione and extending that to a larger set of metabolites in the steroid pathway. RA classification using metabolic profiles shows a sensitivity of 91% and specificity of 88%. Steroid levels show variation among the RA patients according to the corticosteroid treatment; lowest in those taking the treatment at the time of the study, higher in those who never took the treatment, and highest in those who took it in the past. Finally, the GGM reflects metabolite relations from the steroidogenesis pathway.

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.

Diagnostic and Prognostic Metabolites Identified for Joint Symptoms in the KORA Population

This study aims at identifying metabolites that significantly associate with self-reported joint symptoms (diagnostic) and metabolites that can predict the change from a symptom-free status to the development of self-reported joint symptoms after a 7 years period (prognostic). More than 300 metabolites were analyzed for 2246 subjects from the longitudinal study of the KORA (Cooperative Health Research in the Region of Augsburg, Germany), specifically the fourth survey S4 and its 7-year follow-up study F4. Two types of self-reported symptoms, chronic joint inflammation and worn out joints, were used for the analyses. Diagnostic analysis identified dysregulated metabolites in cases with symptoms compared with controls. Prognostic analysis identified metabolites that differentiate subjects in S4 who remained symptom-free after 7 years (F4) from those who developed any combination of symptoms. 48 metabolites were identified as nominally significantly (p < 0.05) associated with the self-reported symptoms in the diagnostic analysis, among which steroids show Bonferroni significance. 45 metabolites were identified as nominally significantly associated with developing symptoms after 7 years, among which hippurate showed Bonferroni significance. We show that metabolic profiles of self-reported joint symptoms are in line with metabolites known to associate with various forms of arthritis and suggest that future studies may benefit from that by investigating the possible use of self-reporting/questionnaire along with metabolic markers for the early referral of patients for further diagnostic workup and treatment of arthritis.

Autonomic function and rheumatoid arthritis: a systematic review

OBJECTIVES

Rheumatoid arthritis (RA) is a chronic inflammatory condition with increased all-cause and cardiovascular mortality. Accumulating evidence indicates that the immune and autonomic nervous systems (ANS) are major contributors to the pathogenesis of cardiovascular disease. We performed the first systematic literature review to determine the prevalence and nature of ANS dysfunction in RA and whether there is a causal relationship between inflammation and ANS function.

METHODS

Electronic databases (MEDLINE, Central and Cochrane Library) were searched for studies of RA patients where autonomic function was assessed.

RESULTS

A total of 40 studies were included. ANS function was assessed by clinical cardiovascular reflex tests (CCTs) (n = 18), heart rate variability (HRV) (n = 15), catecholamines (n = 5), biomarkers of sympathetic activity (n = 5), sympathetic skin responses (n = 5), cardiac baroreflex sensitivity (cBRS) (n = 2) and pupillary light reflexes (n = 2). A prevalence of ~60% (median, range: 20-86%) of ANS dysfunction (defined by abnormal CCTs) in RA was reported in 9 small studies. Overall, 73% of studies (n = 27/37) reported at least one of the following abnormalities in ANS function: parasympathetic dysfunction (n = 20/26, 77%), sympathetic dysfunction (n = 16/30, 53%) or reduced cBRS (n = 1/2, 50%). An association between increased inflammation and ANS dysfunction was found (n = 7/19, 37%), although causal relationships could not be elucidated from the studies available to date.

CONCLUSIONS

ANS dysfunction is prevalent in ~60% of RA patients. The main pattern of dysfunction is impairment of cardiovascular reflexes and altered HRV, indicative of reduced cardiac parasympathetic (strong evidence) activity and elevated cardiac sympathetic activity (limited evidence). The literature to date is underpowered to determine causal relationships between inflammation and ANS dysfunction in RA.

Role of neuroendocrine and neuroimmune mechanisms in chronic inflammatory rheumatic diseases--the 10-year update

BACKGROUND

Neuroendocrine immunology in musculoskeletal diseases is an emerging scientific field. It deals with the aspects of efferent neuronal and neurohormonal bearing on the peripheral immune and musculoskeletal systems. This review aims to add new information that appeared since 2001.

SEARCH STRATEGY

The following PubMed search sentence was used to find a total of 15,462 references between 2001 and March 2013: "(rheum* OR SLE OR vasculitis) AND (nerve OR hormone OR neurotransmitter OR neuropeptide OR steroid)." In a continuous process, year by year, this search strategy yielded relevant papers that were screened and collected in a database, which build the platform of this review.

RESULTS

The main findings are the anti-inflammatory role of androgens, the loss of androgens (androgen drain), the bimodal role of estrogens (support B cells and inhibit macrophages and T cells), increased conversion of androgens to estrogens in inflammation (androgen drain), disturbances of the gonadal axis, inadequate amount of HPA axis hormones relative to inflammation (disproportion principle), biologics partly improve neuroendocrine axes, anti-corticotropin-releasing hormone therapies improve inflammation (antalarmin), bimodal role of the sympathetic nervous system (proinflammatory early, anti-inflammatory late-most probably due to catecholamine-producing local cells), anti-inflammatory role of alpha melanocyte-stimulating hormone, vasoactive intestinal peptide, and the Vagus nerve via α7 nicotinergic receptors. Circadian rhythms of hypothalamic origin are responsible for circadian rhythms of symptoms (neuroimmune link revealed). Important new pain-sensitizing immunological pathways were found in the last decade.

CONCLUSIONS

The last decade brought much new information that gave birth to the first therapies of chronic inflammatory diseases on the basis of neuroendocrine immune targets. In addition, a new theory linked evolutionary medicine, neuroendocrine regulation of distribution of energy-rich fuels, and volume regulation that can explain many disease sequelae in patients with chronic inflammatory diseases.

Adrenomedullary response to glucagon in patients with primary Sjögren's syndrome

Several studies showed signs of autonomic dysfunction in patients with primary Sjögren's syndrome (pSS). Adrenomedullary function might be of importance for pSS pathogenesis by affecting salivary gland functions and modulating immune responses. The aim of the study was to evaluate the adrenomedullary hormonal system in patients with pSS. The glucagon test (1 mg i.v.) was performed in 18 pSS patients and 13 control subjects. During the test each patient had electrocardiographic and impedance cardiographic monitoring. Plasma epinephrine and norepinephrine were assayed by liquid chromatography with electrochemical detection after batch alumina extraction. Baseline concentrations of epinephrine and norepinephrine were comparable between pSS and controls. Glucagon administration induced a significant increase in systolic blood pressure, diastolic blood pressure, heart rate, cardiac output (P < 0.01), and stroke volume; however, the changes were comparable between pSS and controls. Epinephrine levels increased (P < 0.01) in response to glucagon administration while norepinephrine concentration did not change. There was no significant difference in neurochemical responses to glucagon between pSS and controls. In conclusion, the present results suggest normal adrenomedullary function in pSS.

Prolactin and autoimmunity

The relationship between prolactin and the immune system has been demonstrated in the last two decades, opening new windows in the field of the immunoendocrinology. Prolactin has an important role in the innate and adaptive immune response. Increased prolactin levels have been described in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome, and systemic sclerosis among others. Hyperprolactinemia is associated with active disease and organ involvement in systemic lupus erythematosus. Therefore, prolactin is an integral member of the immunoneuroendocrinology network and seems to have a role in pathogenesis of autoimmune diseases. Few controlled studies of dopamine agonist treatment in humans with autoimmune disease have been conducted only in systemic lupus erythematosus patients, which support the potential efficacy of such agents even during pregnancy and postpartum. Further studies are necessary to elucidate the mechanisms by which prolactin affects autoimmune disease activity, increase the inflammatory mechanism, and determine the role of anti-prolactinemic drugs to regulate the immune/inflammatory process.

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.

Adrenomedullary response to hypoglycemia in first-degree relatives of patients with rheumatoid arthritis

Our recent studies showed blunted adrenomedullary responses to insulin-induced hypoglycemia in premenopausal females with rheumatoid arthritis (RA) and systemic sclerosis, suggesting dysregulation of the adrenomedullary hormonal system (AMHS). Since no relationship has been found between degree of AMHS dysfunction and clinical or inflammatory parameters in those patients, we hypothesize the presence of an inherited perturbation of the AMHS. To test this hypothesis, we evaluated adrenomedullary responses to insulin-induced hypoglycemia (0.1 IU/kg) in premenopausal female subjects: 17 glucocorticoid-naïve RA patients, 15 healthy first-degree family members (FDR), and 18 age- and body mass index-matched healthy controls. Our results demonstrate that when compared to controls, RA patients had lower baseline epinephrine levels (P= 0.01) and lower area under response curve (AUC) levels of norepinephrine (P < 0.001) and epinephrine (P < 0.003). In contrast, FDR had lower (P= 0.001) AUC levels of norepinephrine compared to controls and higher (P= 0.033) AUC levels of epinephrine compared to RA patients. There were no significant differences in epinephrine response between FDR and controls. Although we found lower norepinephrine responses to hypoglycemia in FDR of RA patients, adrenomedullary responses to hypoglycemia does not appear to be altered to the degree found in RA patients.

Adrenocortical response to low-dose ACTH test in female patients with rheumatoid arthritis

Alterations in adrenal steroid production have been suggested in females with rheumatoid arthritis (RA). The aim of the present study was to assess adrenocortical function in RA females. We examined 11 female RA patients (RA: age 30 +/- 2 years, BMI 21.0 +/- 0.7 kg/m(2)) and 10 matched healthy controls (C: age 31 +/- 1 years, BMI 21.6 +/- 0.6 kg/m(2)). Low-dose adrenocorticotropic hormone (ACTH) test (i.v. bolus of 1 microg synthetic ACTH) was performed at 10.00 h with blood sampling every 15 min for 90 min. Cortisol, 17-OH-progesterone (17OHP), androstenedione (ASD), and dehydroepiandrosterone (DHEA) were assayed in plasma. Baseline cortisol levels were higher in RA patients (RA: 385 +/- 38 versus C: 229 +/- 28 nmol/L, P= 0.007). In both study groups, ACTH administration increased all the four steroids measured (P < 0.001). Cortisol response to ACTH administration was diminished in RA patients when compared to controls (Delta(max): 284 +/- 24 in RA versus 424 +/- 31 nmol/L in C, P= 0.002). ACTH-induced maximal rise in plasma DHEA was significantly lower in RA patients when compared to controls (Delta(max): 2.59 +/- 0.68 in RA versus 5.57 +/- 1.25 ng/mL in C, P= 0.015). No significant between-groups differences were found in responses of ASD or 17OHP. The molar ratio of ASD:cortisol was significantly lower (P < 0.05) in RA patients at base line, but did not differ during ACTH test. After ACTH bolus, the cortisol:17OHP ratio decreased significantly in the RA group (P < 0.001), whereas there was no change in the control group. The present results show decreased secretion of cortisol and DHEA in RA patients in response to ACTH, suggesting a subtle HPA hypofunction at the adrenocortical level.

Heart rate variability and catecholamines during hypoglycemia and orthostasis

The low frequency component of heart rate variability (HRV) is believed to be affected by sympathetic activity, but an evidence for this suggestion remains controversial. This study analyzed association between HRV and plasma catecholamines in response to two distinct conditions activating sympathetic nervous system. Changes in HRV were analysed from ECG recording and plasma norepinephrine and epinephrine levels were measured in response to head-up tilt (60 degrees, 10 min) in 14 healthy volunteers (6 males, mean age 27.2+/-0.8) and in response to insulin-induced hypoglycemia (0.1 IU per kg, i.v. bolus) in 11 healthy volunteers (5 males, mean age 26.6+/-0.9 yr). Normalized low frequency power, low/high frequency ratio, plasma catecholamines increased, whereas normalized high frequency power decreased in response to head-up tilt or hypoglycemia. When analyzed individual time points of orthostatic test, plasma epinephrine correlated positively with low/high frequency ratio and negatively with normalized high frequency at the 3rd min of the head-up tilt. When all data at different time points were pooled significant correlations were found between catecholamines and normalized low frequency power and low/high frequency ratio. In insulin-induced hypoglycemia test plasma epinephrine correlated negatively with normalized high frequency power at the 30th minute. When all data measured at different time points were pooled no significant correlation was found between plasma catecholamines and HRV parameters. In conclusion, the present study shows an increase in low frequency component of HRV in response to orthostasis or hypoglycemia with significant, however inconsistent association to changes in plasma catecholamines.

[Significance of dehydroepiandrosterone and dehydroepiandrosterone sulfate in different diseases]

Dehydroepiandrosterone and dehydroepiandrosterone-sulfate are precursors of androgens and estrogens, support the gonadal sexual steroid production. The levels of dehydroepiandrosterone and dehydroepiandrosterone-sulfate are maximal between the ages of 20 and 30 years, then start a decline of 2% per year, leaving a residual of 10-20% of the peak production by the eight decade of life. The age-associated decrease may lead to osteoporosis, deterioration of lipid-metabolism, cardiovascular diseases and second type of diabetes mellitus. Decreased levels were found in autoimmune diseases and in sexual dysfunction, too. Intracrinology describes the formation of active hormones which exert their action in the same cells where synthesis took place without release into the pericellular compartment. The high local androgen and estrogen concentration may be important in the pathomechanism of hirsutism, acne, seborrhea, breast and prostate cancer. Administration of dehydroepiandrosterone resulted in a reduction of postmenopausal osteoporosis, also the decreased symptoms in systemic lupus erythematosis, psychiatric diseases and sexual disfunction. The authors summarize the metabolism of dehydroepiandrosterone and dehydroepiandrosterone-sulfate and their role in different diseases.

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.

Prolactin and Growth Hormone Responses to Hypoglycemia in Patients with Systemic Sclerosis and Psoriatic Arthritis

This study compared prolactin (PRL) and growth hormone (GH) responses to hypoglycemia in premenopausal females with systemic sclerosis (SSc) and psoriatic arthritis (PsA) with those in matched healthy controls. No differences were found in glucose and GH responses to hypoglycemia in both groups of patients compared to controls. SSc patients had lower PRL response (P < 0.05) to hypoglycemia compared to controls. PRL response tended to be lower also in PsA patients, however the difference did not reach level of statistical significance (P = 0.11). The present study showed decreased PRL response to hypoglycemia in premenopausal females with SSc.

The Impact of Stressors on Health Status and Hypothalamic-Pituitary-Adrenal Axis and Autonomic Nervous System Responsiveness in Rheumatoid Arthritis

The hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) are critically involved in inflammation and are activated by stress. This suggests that stressful circumstances may affect the chronic inflammation of rheumatoid arthritis (RA). Fifty-six scientific publications of the past 15 years were reviewed to get insight into the possible impact of stressors (grouped in five categories) on the health status and HPA axis and ANS functioning of adult patients with RA. Our findings in this review were: (1) In response to mental and physical effort and applied physiological stressors, patients demonstrate ANS hyporesponsiveness and "too normal" HPA axis responsiveness considering the elevated immune activity. A premorbid defect, past and current inflammatory activity, past and current stress, and physical deconditioning may explain disturbed physiological responses. (2) After brief naturalistic stressors, self-perceived and clinician's ratings of disease activity are increased; inflammation parameters have been insufficiently examined. (3) Major life events do not univocally affect disease status, but appear able to modify disease activity in a positive or negative way, depending on the nature, duration, and dose of the accompanying physiological stress response. (4) Enduring (e.g., work-related or interpersonal) stressors are associated with perceived health. Because this stressor category mingles with personality variables, the mere observation of a correlation does not prove that chronic stressors provoke health changes, although this might be the case. (5) Not one study rigorously examined the prospective hypothesis that past stressors (e.g., childhood victimization or pre-onset stressful incidents) may trigger RA or aggravate existing RA, which is a realistic belief for some patients.

Hypoglycemia, an Old Tool for New Findings in the Adrenomedullary Hormonal System in Patients with Rheumatic Diseases

Over the past decades, research in patients with rheumatic disorders showed enormous progress in detecting various perturbations of the neuroendocrine system including those affecting autonomic nervous function. There is, however, a substantial lack of data on adrenomedullary hormonal system (AMHS) function in those patients. Insulin-induced hypoglycemia (IIH) represents a metabolic stressor, which elicits a counterregulatory stress response not only of the hypothalamic-pituitary axis but also of the AMHS. Therefore, in addition to traditional testing of hypothalamic-pituitary function, IIH can be used as a well-controlled functional test of the AMHS. Our recent studies showed, for the first time, attenuated epinephrine and norepinephrine responses to IIH in premenopausal females with rheumatoid arthritis (RA) and systemic sclerosis (SSc). These findings are suggestive of downregulation, or possibly defects, of the AMHS in those patients. This article reviews mechanism of the AMHS activation during IIH and demonstrates applications of the test in neuroendocrine-immune research.