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Rainer H Straub

Publications and source records attributed to Rainer H Straub.

At least 55 records · Page 3Linked to original sources
PubMed2004

Synovial fluid estrogens in rheumatoid arthritis.

Experimental and clinical evidence suggest that immune reactivity is modulated by gender. Immune reactivity is greater in females than in males and lymphocytes and monocytes from female subjects shows higher antigen presenting activity and mitogenic responses. Steroid hormones can be converted along defined pathways to downstream hormones in the periphery. The conversion of dehydroepiandrosterone (DHEA) in target macrophages leads to an increase of downstream effector hormones (including estrogens), which may be an important factor for local immunomodulation at least in RA synovitis. The presence in the RA synovial fluids (SF) of an altered sex hormone balance resulting in lower immunosuppressive androgens and higher immunoenhancing estrogens, might determine a favorable condition for the development of the immuno-mediated RA synovitis and synovial hyperplasia. The increased estrogen concentration observed in RA SF of both sexes are characterized by the hydroxylated forms, in particular 16alpha-hydroxyestrone, that is a mitogenic and proliferative endogenous hormone. In contrast to 16alpha-hydroxylated estrogens, the 2-hydroxylated forms inhibit growth promoting effects of E2 and were found low in RA SF. Therefore, dose-related conversion to pro- or anti-inflammatory downstream metabolites of estrogens might support the dual role of estrogens (pro or anti-inflammatory) for example during estrogen replacement therapy, depending on local concentration (i.e. SF in RA) of 16alpha-hydroxyestrone or 2-hydroxyestrogens.

Arthritis, Rheumatoid↗
PubMed2004

More sympathy for autoimmunity with neuropeptide Y?

Substantial evidence indicates a dysfunctional communication between the sympathetic nervous system and the immune system in Th1-mediated autoimmune diseases, such as rheumatoid arthritis and multiple sclerosis. In this Opinion, we propose that the sympathetic regulation of immunity is not only mediated by catecholamines but also involves neuropeptide Y (NPY), an additional postganglionic SNS transmitter that is shown to modulate various immunological functions in vitro and in vivo. Based on recent experimental findings, we believe that a more precise understanding of the role of NPY in the regulation of autoimmune Th1 cells will provide novel insights into the neuroimmunological basis of autoimmunity.

Autoimmunity↗
PubMed2004

Reduced tissue immigration of monocytes by neuropeptide Y during endotoxemia is associated with Y2 receptor activation.

Neuropeptide Y (NPY) increases survival in experimental septic shock, which might be mediated by cardiovascular and/or immunological effects. To study the latter hypothesis, we monitored blood leukocyte subsets over 96 h after intravenous (i.v.) application of LPS in chronically i.v.-cannulated rats. LPS induced a dramatic leukopenia at 4 h after challenge, which was blunted in NPY-treated animals by stabilizing granulocyte and T-lymphocyte numbers. In addition, NPY treatment prevented tissue immigration of monocytes at early time points and consecutively mobilized activated monocytes from the third day after challenge. RT-PCR and in vitro adhesion studies provided evidence for a NPY Y2 receptor-mediated effect on monocytes. Thus, NPY treatment has profound receptor-specific effects on the migration and adhesion of leukocytes under endotoxemic conditions.

Animals↗
PubMed2004

Complexity of the bi-directional neuroimmune junction in the spleen.

The spleen is a crucial secondary lymphoid organ for circulating infectious agents that is densely innervated by sympathetic nerve fibres. Sympathetic nerve endings contact immune cells within the spleen, particularly in areas of T cells and macrophages (building the neuroimmune junction). Neurotransmitters are released into the vicinity of nerve terminals and bind to specific postsynaptic receptors on the surface of these cells. Local bi-directionality exists through cytokines and neurotransmitters from immune cells that modulate the release of sympathetic neurotransmitters from nerve terminals. This complex 'dialog' depends on microenvironmental factors such as infectious agents, and this 'conversation' is needed to balance the function of both the sympathetic nerve terminal and the immune system. Activation of the sympathetic nervous system and also the resting sympathetic nervous tone are important for controlling innate and adaptive immune responses.

Animals↗
PubMed2004

Patients with rheumatoid arthritis and systemic lupus erythematosus have increased renal excretion of mitogenic estrogens in relation to endogenous antiestrogens.

OBJECTIVE: In patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), 17beta-estradiol was thought to play a dual pro- and antiinflammatory role depending on its concentration or probably conversion to downstream mitogenic 16 alpha-hydroxyestrone or naturally occurring antiestrogens such as 2-hydroxyestrone. We compared renal excretion of these 2 types of estrogens in healthy subjects and patients with RA and SLE. METHODS: In a prospective study with 30 patients with RA, 32 with SLE, and 54 healthy subjects, we measured urinary levels of 16 alpha-hydroxyestrone and 2-hydroxyestrogens by enzyme immunoassay. We studied renal excretion to estimate the time-integral of hormone production. RESULTS: Urinary concentration and total urinary loss of 2-hydroxyestrogens was 10 times higher in healthy subjects compared to patients with either SLE or RA irrespective of prior prednisolone treatment or sex. The urinary concentration and loss of 16 alpha-hydroxyestrone did not differ between healthy subjects and patients with RA/SLE. The ratio of urinary 16 alpha-hydroxyestrone/2-hydroxyestrogens was more than 20 times higher in RA and SLE than healthy subjects irrespective of prior glucocorticoid treatment or sex. CONCLUSION: This study in RA and SLE patients clearly demonstrates a large shift to mitogenic estrogens in relation to endogenous antiestrogens. Both steroids are converted from the precursor 17beta-estradiol and estrone. In patients with RA and SLE, the magnitude of conversion to the mitogenic 16 alpha-hydroxyestrone is greatly upregulated, which likely contributes to maintenance of the proliferative state in these diseases.

Arthritis, Rheumatoid↗
PubMed2003

Induction of cytokines and adhesion molecules in stable hemodialysis patients: is there an effect of membrane material?

BACKGROUND/AIMS: The aim of this study was to examine the effects of a biocompatible and a nonbiocompatible hemodialysis membrane on the secretion of cytokines and their specific antagonists as well as on the expression of adhesion molecules. METHODS: A crossover study using cuprophane (CU) and polysulfone (PS) dialyzers and measurements of serum tumor necrosis factor (TNF)-alpha, soluble TNF receptors, interleukin (IL)-6, IL-6 receptor, IL-2 receptor, IL-1 receptor antagonist and the adhesion molecules intercellular adhesion molecule 1, endothelial leukocyte adhesion molecule and vascular cell adhesion molecule was performed in 19 hemodialysis patients. 44 healthy volunteers served as controls. RESULTS: All of the measured cytokines and cytokine antagonists as well as all adhesion molecules were significantly elevated in hemodialysis patients compared to controls. There was a significant increase in TNF-alpha during a dialysis session with a CU dialyzer, but only a moderate increase using a PS dialyzer. None of the other cytokines and adhesion molecules were changed during a dialysis session. We were also able to show an upregulation of adhesion molecules in dialysis patients. CONCLUSION: Our study clearly demonstrates that levels of inflammatory cytokines as well as their antagonists and adhesion molecules are elevated in patients on hemodialysis therapy. Baseline values before the start of a dialysis session did not show any differences with regard to the usage of CU or PS dialysis membranes. However, CU dialyzers led to a significantly greater stimulation of TNF-alpha during the dialysis session in comparison to PS membranes, suggesting a higher degree of bioincompatibility.

Adult↗
PubMed2003

Histopathological parameters as predictors for the course of Crohn's disease.

BACKGROUND: Recent classification systems discriminate penetrating Crohn's disease (CD) from stricturing and non-stricturing/non-penetrating CD. As yet, no easily detectable marker is known that can predict the course of CD. Individual, clinical course-specific new treatment schemes would be highly desirable for different potentially divergent pathophysiological pathways (e.g., fistula vs stenosis). METHODS: Intestinal tissue biopsies from 63 CD patients with a disease follow-up of up to 7 years were studied retrospectively. In biopsy specimens, 34 histopathological features present prior to the onset of (a) strictures or (b) fistulas were evaluated and compared with biopsies from patients with non-stricturing/non-penetrating disease. RESULTS: Five histomorphological parameters demonstrated significant associations to different disease courses when applying univariate analysis. In a multivariate logistic regression model (1) severe lymphocytic infiltration of the lamina propria, (2) presence of crypt atrophy, and (3) absence of lymphocytic infiltration of the epithelium are the best variables to predict an uncomplicated disease course (Nagelkerke R2=0.329; P=0.001). The combination of these parameters has a sensitivity of 67% and a specificity of 83% to predict non-stricturing/non-penetrating disease (positive predictive value=0.75). CONCLUSION: Histopathological parameters may help to predict complications of CD prior to their onset. The results of this study have to be confirmed prospectively.

Adult↗
PubMed2003

Long-term anti-tumor necrosis factor antibody therapy in rheumatoid arthritis patients sensitizes the pituitary gland and favors adrenal androgen secretion.

OBJECTIVE: New insights into the role of tumor necrosis factor (TNF) in the pathogenesis of rheumatoid arthritis (RA) have expanded our understanding about the possible mechanisms by which anti-TNF antibody therapy reduces local synovial inflammation. Beyond local effects, anti-TNF treatment may modulate systemic antiinflammatory pathways such as the hypothalamic-pituitary-adrenal (HPA) axis. This longitudinal anti-TNF therapy study was designed to assess these effects in RA patients. METHODS: RA patients were given 5 infusions of anti-TNF at weeks 0, 2, 6, 10, and 14, with followup observation until week 16. We measured serum levels of interleukin-6 (IL-6), adrenocorticotropic hormone (ACTH), 17-hydroxyprogesterone (17[OH]progesterone), cortisol, cortisone, androstenedione (ASD), dehydroepiandrosterone (DHEA), and DHEA sulfate in 19 RA patients. RESULTS: Upon treatment with anti-TNF, we observed a fast decrease in the levels of serum IL-6, particularly in RA patients who did not receive parallel prednisolone treatment (P = 0.043). In these RA patients who had not received prednisolone, the mean serum ACTH levels sharply increased after every injection of anti-TNF, which indicates a sensitization of the pituitary gland (not observed for the adrenal gland). During treatment, the ratio of serum cortisol to serum ACTH decreased, which also indicates a sensitization of the pituitary gland (P < 0.001), and which was paralleled by constant cortisol secretion. The adrenal androgen ASD significantly increased relative to its precursor 17(OH)progesterone (P = 0.013) and relative to cortisol (P = 0.009), which indicates a normalization of adrenal androgen production. The comparison of patients previously treated with prednisolone and those without previous prednisolone revealed marked differences in the central and adrenal level of this endocrine axis during long-term anti-TNF therapy. CONCLUSION: Long-term therapy with anti-TNF sensitizes the pituitary gland and improves adrenal androgen secretion in patients who have not previously received prednisolone treatment. These changes are indicative of normalization of the HPA axis and must therefore be considered as evidence of an additional antiinflammatory influence of anti-TNF treatment in patients with RA.

17-alpha-Hydroxyprogesterone↗
PubMed2003

Via beta-adrenoceptors, stimulation of extrasplenic sympathetic nerve fibers inhibits lipopolysaccharide-induced TNF secretion in perfused rat spleen.

Using a spleen slice microsuperfusion technique in mice, we have previously characterized the role of norepinephrine (NE) and other neurotransmitters for sympathetic modulation of IL-6 and TNF secretion of splenic macrophages. Since experiments in spleen slices do not reflect the situation of an entire perfused organ, we investigated sympathetic modulation of lipopolysaccharide (LPS)-induced secretion of IL-6 and TNF in perfusion experiments of rat spleen. In an organ bath, perfusion was performed in explanted whole spleens, and catecholamines and cytokines were measured by HPLC and ELISA, respectively. Release of NE depended on stimulation frequency (maximum at 10 Hz). Apart from NE, perfusates also contained significant amounts of dopamine and epinephrine. Furthermore, perfusate epinephrine levels correlated positively with perfusate NE levels (RRank=0.750, p<0.001) but not with plasma epinephrine concentrations. This indicates that epinephrine is a conversion product of sympathetically released NE. Early electrical stimulation of extrasplenic splenic nerves, 20 min after administration of LPS, significantly inhibited TNF secretion. This electrically induced effect was abrogated by simultaneous administration of propranolol (10(-6) M) but it was not influenced by administration of either an alpha1- or alpha2-adrenergic antagonist. Late electrical stimulation of splenic nerves, 2.5 h after administration of LPS, did not change TNF secretion. Interestingly, no influence of early or late sympathetic nerve fiber stimulation on IL-6 secretion was observed. In conclusion, this is the first perfusion study of the entire spleen that demonstrates that early electrical stimulation of sympathetic splenic nerve fibers directly inhibits LPS-induced TNF secretion. This study corroborates the idea that splenic sympathetic nerves are able to inhibit important activators of the innate immune system when stimulation happens very early or even prior to their induction by LPS.

Adrenergic Fibers↗
PubMed2003

Relevance of neuropeptide Y for the neuroimmune crosstalk.

Both cellular and humoral functions of the immune system are modulated by the sympathetic nervous system (SNS). This interaction is mainly mediated by the release of catecholamines (CA) and their receptor-specific action on immune cells. However, neuropeptide Y (NPY), also present in sympathetic nerve terminals, is released upon SNS-stimulation. NPY modulates potent immunological effects in vitro and in vivo, such as differentiation of T helper cells, monocyte mediator release, NK cell activation, and immune cell redistribution. In addition to this direct action within the neuroimmune crosstalk, NPY is also able to modulate the immunomodulatory effects of other neurotransmitters, thereby acting as a neuroimmune co-transmitter. This review will discuss key findings from recent studies, provide implications for the clinical situation, and integrate the pleiotropic functions of NPY in the context of neuroimmune interactions.

Animals↗
PubMed2003

The social environment affects behaviour and androgens, but not cortisol in pregnant female guinea pigs.

In guinea pigs the behaviour of male offspring is infantilized in adulthood, when their mothers had lived in an unstable social environment during pregnancy and lactation (Kaiser and Sachser, Psychoneuroendocrinology, 26 (2001) 503). The present study was conducted to elucidate the mechanisms bringing about this phenomenon. Therefore, the spontaneous behaviour and endocrine parameters of females were compared that either lived in a stable social environment (SSE) during pregnancy (SE-females) or in an unstable social environment (USE) during this period of life (UE-females). The SSE was made by keeping the group composition (one male, five females) constant; in the USE situation (one male, five females) every third day two females from different groups were exchanged. The spontaneous behaviour of the UE-females was recorded on three successive days: the day before, the day of and the day after the transfer from one group to another. The behaviour of the SE-females was recorded at corresponding times. In addition, serum concentrations of cortisol, dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulfate (DHEAS) concentrations were determined. After transfer to another group UE-females showed distinctly more orientation behaviour and they received significantly higher amounts of courtship and sexual behaviour from the males than SE-females which remained in their familiar groups. In turn, UE-females displayed significantly higher amounts of urine spray towards the male, a defensive aggressive behavioural pattern. No differences were found in offensive aggressive and socio-positive behaviours between UE- and SE-females. With respect to endocrine parameters the transfer to an unfamiliar group did not cause an increase of cortisol, that is UE- and SE-females did not differ significantly. DHEAS and in part DHEA concentrations, however, were significantly lower in UE- than SE-females. Thus, for the first time it is shown that the social environment during pregnancy has significant effects on the androgen concentrations in female guinea pigs. Moreover, a decrease of androgens in pregnant females may be related to the infantilization of their male offspring.

Androgens↗
PubMed2003

Myocardial IL-6 regulation by neurohormones--an in vitro superfusion study.

BACKGROUND: Interleukin-6 (IL-6) is expressed in the myocardium and has been implicated in cell proliferation, negative inotropic effects and myocardial hypertrophy. To determine whether myocardial IL-6 is modified by neurohumoral and immunoregulatory stimuli, we studied the effects of lipopolysaccharide (LPS), corticosterone (CS), isoproterenol and angiotensin II on myocardial IL-6 secretion in superfused myocardium. METHODS: Slices of rat left ventricular myocardium were superfused in 80 microl chambers for up to 5h. LPS (1, 50, and 100 microg/ml), CS (10(-7), 10(-6), and 10(-5)M, DSMO as vehicle), isoproterenol (10(-6), 10(-7), and 10(-8)M) and angiotensin II (10(-5), 10(-7), and 10(-9)M) were added to the culture medium at hour 2. IL-6 was measured in the perfusate by ELISA. RESULTS: Physiological corticosterone concentrations (10(-7)M) resulted in an increase in IL-6 concentration (142%) while high doses of steroid decreased IL-6 significantly (CS 10(-6)M: 88+/-14%,p<.05; CS 10(-5): 91+/-9%,p<.05) after 5h. Left ventricular IL-6 secretion was significantly stimulated by LPS 50 microg/ml (3262+/-1684% vs. CTRL: 116+/-34%, p<.01). Isoproterenol treatment increased in IL-6 secretion compared to controls with and without CS, while angiotensin II reduced IL-6 concentration only in combination with CS. CONCLUSION: Myocardial IL-6 secretion is modulated by physiological concentrations of corticosterone or angiotensin II and can be induced by LPS or isoproterenol, indicating a tight regulation of this cytokine. Suppression of cytokine expression within the heart might be a potential therapeutic goal in the treatment of various cardiovascular diseases.

Angiotensin II↗
PubMed2003

Integrated evolutionary, immunological, and neuroendocrine framework for the pathogenesis of chronic disabling inflammatory diseases.

The pathogenesis of chronic disabling inflammatory diseases (CDIDs) is poorly understood. Current concepts that focus on abnormalities of the immune system are, in our view, incomplete. Here we propose that chronic disruption of homeostasis through abnormal neuronal and endocrine host responses to transient inflammatory reactions contributes to the appearance of CDIDs. Coordinated reactions of the supersystems (immune, nervous, endocrine, and reproductive) that maintain homeostasis have been evolutionarily conserved to respond to and eliminate foreign agents over a period of days to a few weeks. If the responses of these supersystems fail to return to normal after elimination of the pathogen, a continuous aggressive immune response is created; this situation can trigger development of CDIDs. Maladaptation of the supersystems during CDIDs has not been evolutionarily conserved but is nevertheless still prevalent because a large proportion of these diseases tend to appear after the reproductive phase. We propose that this integrated systems hypothesis may permit better identification of a patient at risk or in the early stages of developing a CDID such as rheumatoid arthritis and enable more coordinated intervention than is presently attempted.

Adaptation, Physiological↗
PubMed2003

During a corticotropin-releasing hormone test in healthy subjects, administration of a beta-adrenergic antagonist induced secretion of cortisol and dehydroepiandrosterone sulfate and inhibited secretion of ACTH.

OBJECTIVE: In chronic inflammatory diseases, serum levels of dehydroepiandrosterone (DHEA) sulfate (DHEAS) are low. Interestingly, several non-inflammatory diseases display similarly low levels of DHEAS which points to other inhibitory factors such as an activated sympathetic nervous system (SNS) (e.g. in patients with heart failure, fibromyalgia, or cancer cachexia). We aimed to identify the influence of the SNS tone on stimulated adrenal steroid secretion in 16 male and 12 female healthy subjects. METHODS: One group were given oral propranolol 2 h before a corticotropin-releasing hormone (CRH) test, and levels of adrenocorticotropin (ACTH), cortisol, 17-hydroxyprogesterone (17OHP), androstenedione, DHEA, and DHEAS were measured. RESULTS: Propranolol treatment decreased heart rate (by 20%), diastolic blood pressure (by 20%), and plasma ACTH, and increased serum cortisol, serum DHEAS, and the molar ratio of cortisol/17OHP, cortisol/DHEA, and DHEAS/DHEA similarly in female and male subjects. CONCLUSIONS: A beta-adrenergic influence seems to decrease CRH-stimulated cortisol in relation to ACTH and 17OHP, and decreases DHEAS in relation to DHEA. Although other workers have found beta-adrenergic stimulation of steroid secretion in cultured adrenocortical cells, the overall systemic influence of the SNS via beta-adrenoceptors seems to inhibit adrenal steroids under unstimulated and stimulated conditions. Sympathetic hyperactivity may be a common denominator for low levels of DHEAS in inflammatory and non-inflammatory diseases.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Serum levels of pregnenolone and 17-hydroxypregnenolone in patients with rheumatoid arthritis and systemic lupus erythematosus: relation to other adrenal hormones.

OBJECTIVE: In patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), low levels of adrenal steroids have been repeatedly demonstrated, but the site of alteration has not been exactly described because measurements of serum pregnenolone and 17-hydroxypregnenolone (17OHPreg) together with other adrenal steroids have never been performed. METHODS: We measured serum levels of adrenal hormones such as pregnenolone, 17OHPreg, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), progesterone (P), 17-hydroxyprogesterone (17OHP), androstenedione (ASD), and cortisol in 24 healthy controls, 24 patients with RA, and 24 patients with SLE. RESULTS: Serum levels of pregnenolone were similar in RA and SLE patients as compared to healthy controls irrespective of prior prednisolone therapy. In all RA and SLE patients (including those with prior prednisolone treatment), serum levels of all measured hormones except pregnenolone were significantly lower as compared to controls. In RA patients without prior prednisolone treatment, serum levels of 17OHPreg, DHEA, cortisol, and ASD were similar to controls, and serum levels of P, 17OHP, and DHEAS were significantly lower as compared to controls. In SLE patients without prior prednisolone treatment, serum levels of 17OHPreg and cortisol were similar, and serum levels of P, 17OHP, ASD, DHEA, and DHEAS were significantly lower as compared to controls. CONCLUSION: The primary hormone of the adrenal steroid cascade, pregnenolone, is almost normal in RA and SLE irrespective of corticosteroid treatment. In patients with RA, we believe that there is a near normal P450scc reaction and a normal double step P450c17 reaction. In SLE patients, the P450scc reaction also seems normal but the second step of the P450c17 reaction seems to be inhibited. In both diseases, cortisol levels remain relatively stable at the expense of other adrenal hormones. This study revealed distinct changes of steroid pathways that are related to the disease entities.

17-alpha-Hydroxypregnenolone↗
PubMed2003

Increased estrogen formation and estrogen to androgen ratio in the synovial fluid of patients with rheumatoid arthritis.

OBJECTIVE: It has been proposed that physiologic levels of estrogens stimulate immune responses whereas androgens suppress inflammatory reactions. Thus, prevalence of synovial androgens relative to estrogens would be favorable in rheumatoid arthritis (RA). We investigated synovial fluid (SF) concentrations of several estrogens and androgens and conversion products of the sex steroid precursor dehydroepiandrosterone (DHEA) in supernatants of mixed synoviocytes. METHODS: SF steroid concentrations were measured by high performance liquid chromotography and mass spectrometry in 12 patients with RA and 8 subjects with traumatic knee injury (noninflammatory controls). Conversion of DHEA to downstream hormones was measured by thin-layer chromatography and phosphorimaging detection in 3 patients with RA and 3 patients with osteoarthritis (OA). RESULTS: Overall, SF concentration of free estrogens tended to be higher in RA patients versus controls (p < 0.06). Molar ratio of free SF estrogens/free SF androgens was elevated in RA compared to controls (1.17 +/- 0.32 vs 0.29 +/- 0.08, without unit; p = 0.017). The free SF concentration of the precursor androstenedione was significantly higher in RA patients than in controls (104.6 +/- 32.6 vs 30.4 +/- 0.4 ng/ml; p = 0.011), and SF estrone the aromatase conversion product of androstenedione was also elevated in RA compared to controls (13.6 +/- 2.6 vs 6.6 +/- 0.8 ng/ml; p = 0.035). The biologically active estrogen derivatives, 16a-hydroxyestrone and 4-hydroxyestradiol, were both higher in RA compared to controls (p = 0.085 and p = 0.044, respectively). In mixed RA synoviocytes, DHEA conversion yielded high local levels of 17beta-estradiol (708 pmol/l = 0.193 ng/ml) compared to testosterone (88 pmol/l = 0.026 ng/ml). CONCLUSION: SF levels of estrogens relative to androgens are significantly elevated, while those of androgens are markedly reduced, in patients with RA compared to controls. This imbalance is most probably due to increased aromatase activity. Thus, an available steroid precursor, such as DHEA, may be rapidly converted to proinflammatory estrogens in the synovial tissue, which may in turn stimulate the inflammatory process in patients with RA.

Adjuvants, Immunologic↗