The hypothalamic-pituitary response in SLE. Regulation of prolactin, growth hormone and cortisol release

Should Renal Inflammation Be Targeted While Treating Hypertension?

Despite extensive research and a plethora of therapeutic options, hypertension continues to be a global burden. Understanding of the pathological roles of known and underexplored cellular and molecular pathways in the development and maintenance of hypertension is critical to advance the field. Immune system overactivation and inflammation in the kidneys are proposed alternative mechanisms of hypertension, and resistant hypertension. Consideration of the pathophysiology of hypertension in chronic inflammatory conditions such as autoimmune diseases, in which patients present with autoimmune-mediated kidney inflammation as well as hypertension, may reveal possible contributors and novel therapeutic targets. In this review, we 1) summarize current therapies used to control blood pressure and their known effects on inflammation; 2) provide evidence on the need to target renal inflammation, specifically, and especially when first-line and combinatory treatment efforts fail; and 3) discuss the efficacy of therapies used to treat autoimmune diseases with a hypertension/renal component. We aim to elucidate the potential of targeting renal inflammation in certain subsets of patients resistant to current therapies.

Lipopolysaccharide Challenge Reveals Hypothalamic-Pituitary-Adrenal Axis Dysfunction in Murine Systemic Lupus Erythematosus

Crosstalk between the brain and innate immune system may be dysregulated in systemic lupus erythematosus (SLE), a chronic autoimmune disease that presents with dysautonomia and aberrant inflammation. The hypothalamic-pituitary-adrenal (HPA) axis is an endogenous neuro-endocrine-immune pathway that can regulate inflammation following activation of vagal afferents. We hypothesized that chronic inflammatory processes in SLE are in part due to HPA axis dysfunction, at the level of either the afferent vagal-paraventricular nuclei (PVN) interface, the anterior pituitary, and/or at the adrenal glands. To study this, we challenged female control and SLE mice with lipopolysaccharide (LPS) and measured c-Fos expression as an index of neuronal activation, plasma adrenocorticotrophic hormone (ACTH) as an index of anterior pituitary function, and plasma corticosterone as an index of adrenal function. We found that c-Fos expression in the PVN, and plasma ACTH and corticosterone were comparable between unchallenged SLE and control mice. PVN c-Fos was increased similarly in control and SLE mice three hours after LPS challenge; however, there were no changes in plasma ACTH amongst any experimental groups post inflammatory challenge. Plasma corticosterone was markedly increased in LPS-challenged SLE mice compared to their vehicle-treated counterparts, but not in controls. Paradoxically, following LPS challenge, brain and spleen TNF-α were elevated in LPS-challenged SLE mice despite heightened plasma corticosterone. This suggests that, despite normal c-Fos expression in the PVN and activation of the HPA axis following LPS challenge, this cumulative response may not adequately defend SLE mice against inflammatory stimuli, leading to abnormally heightened innate immune responses and peripheral inflammation.

Functional disturbance of the stress-adaptation system in patients with scleroderma

There have been several reports indicating the association between recent stress experiences and the onset or the exacerbation of rheumatic diseases, although few such reports exist in patients with scleroderma (SSc). The present study was performed to elucidate whether there were any functional disturbances in the neuro-endocrine-immune system as a homeostatic system upon stress in SSc patients. Various serum levels of stress-related hormones and cytokines were examined before and after a mental calculation stress test, and a basal questionnaire study of sense of coherence (SOC, which is related to the ability to cope with stress), recent stress experiences, and quality of life (QOL) was performed in 17 SSc patients and in 38 healthy volunteers. Physical QOL state was impaired in patients, but there were no differences in recent stress experiences and SOC scores between patients and controls. Basal serum cortisol levels were similar in patients and controls, but increased levels of proinflammatory cytokine and noradrenalin were seen in SSc patients. Characteristically, contrary to the control group, whose cortisol levels increased significantly following the mental calculation stress test, no significant increase was observed in the patients when post-test cortisol levels were compared to pre-test levels, suggesting a defect in the normal cortisol response upon stress in SSc patients. The present results suggest that there may be impaired function of the neuro-endocrine-immune system upon stress in SSc patients.

Adrenal cortisol secretion capacity in children and adolescents with new-onset, mild Crohn's disease

OBJECTIVES

To evaluate the integrity of the hypothalamic-pituitary-adrenal axis in active Crohn's disease (CD) among children and adolescents.

STUDY DESIGN

We retrieved data on patients with CD who participated in a prospective study where budesonide treatment was evaluated. Basal and adrenocorticotropic hormone and corticotropin-stimulated cortisol levels in 52 children and adolescents with CD were compared with levels obtained in 52 age-matched control subjects. Correlations of cortisol levels with pediatric CD activity index and C-reactive protein (CRP) as an inflammatory marker were also assessed.

RESULTS

Both basal and stimulated cortisol levels in CD were significantly higher than in control subjects: 364 +/- 173 versus 290 +/- 122 nmol/L (P = .029) and 865 +/- 236 versus 738 +/- 148 nmol/L (P < or = .001), respectively. Cortisol levels were correlated with CRP but not with pediatric CD activity index. Unlike in the control group, stimulated cortisol levels in patients with CD were not correlated with basal levels but rather with CRP (positive correlation) and age at diagnosis (negative correlation).

CONCLUSIONS

Contrary to previous reports suggesting that dysregulation of the hypothalamic-pituitary-adrenal axis is implicated in the susceptibility to and severity of CD and other chronic inflammatory diseases, we demonstrated an adequate response of this axis in pediatric CD, in proportion to the inflammation severity.

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.

Growth Hormone/Insulin-Like Growth Factor–I System and Connective Tissues: Basic Aspects and Clinical Implications

This article reviews basic and clinical aspects of the effects of growth hormone and insulin-like growth factor-I on the connective tissues.

The hypothalamic-pituitary-adrenal axis in the pathogenesis of rheumatic diseases

Many studies have demonstrated altered HPA axis activity in patients with rheumatic diseases. In the case of autoimmune inflammatory diseases, circumstantial evidence suggests that failure of the neuroendocrine-immune regulatory loop may lead to insufficient production of endogenous glucocorticoid. Nevertheless, in human autoimmune disease, it is not possible to determine if altered HPA axis activity predates the onset of chronic inflammation. Animal studies and some early genetic studies in RA patients lend credibility to the argument that insufficient HPA axis response to inflammatory stimuli may increase susceptibility to, or severity of, these diseases. Most patients with rheumatic diseases complain of musculoskeletal pain. There is evidence of HPA axis involvement in acute and chronic pain. In the case of FM, pain cannot be explained on the basis of inflammation or altered musculoskeletal anatomy. This has led to the hypothesis that central nervous system mechanisms contribute to the symptom of somatic pain. Again, it is unclear if the observed HPA axis abnormalities reflect pre-existing vulnerability to the FM spectrum of disease, or whether chronic somatic symptoms alter HPA axis activity. Availability of technology to study better central components of the HPA axis may shed further light on its role in the pathogenesis of inflammatory autoimmune rheumatic diseases and musculoskeletal pain syndromes.

Lupus flare associated with growth hormone

This case illustrates a young man with an 11 y history of systemic lupus erythematosus who developed lupus flare after a 9-month use of growth hormone (GH) for the treatment of growth retardation. The course of disease was improving after GH cessation and treatment with high dose corticosteroids and intravenous cyclophosphamide pulse therapy.