The immune-hypothalamic-pituitary-adrenal axis

The physiologic effects of pain on the endocrine system

Severe pain has profound physiologic effects on the endocrine system. Serum hormone abnormalities may result and these serve as biomarkers for the presence of severe pain and the need to replace hormones to achieve pain control. Initially severe pain causes a hyperarousal of the hypothalamic-pituitary-adrenal system which results in elevated serum hormone levels such as adrenocorticotropin, cortisol, and pregnenolone. If the severe pain does not abate, however, the system cannot maintain its normal hormone production and serum levels of some hormones may drop below normal range. Some hormones are so critical to pain control that a deficiency may enhance pain and retard healing.

Pharmacokinetics and Pharmacodynamic Response of Methylprednisolone in Premenopausal Renal Transplant Recipients

Chronic glucocorticoid therapy is prescribed in renal transplant recipients according to empiric dose-tapering schedules, which assume a similar pharmacologic response in men and women. The study objectives were (a) to compare the pharmacokinetics of methylprednisolone in premenopausal renal transplant recipients with previously studied male counterparts and (b) to describe the pharmacodynamic response of the hypothalamic-pituitary-adrenal axis during chronic steroid therapy. Thirteen stable premenopausal subjects (ages 30 to </=49 years) receiving chronic glucocorticoid therapy were evaluated for methylprednisolone, cortisol, and adrenocorticotropin hormone (ACTH) over 24 hours after an intravenous infusion of methylprednisolone sodium succinate. Most patients were evaluated during the luteal phase of the menstrual cycle. Pharmacokinetic parameters of methylprednisolone with cortisol and ACTH responses were determined. Results were compared to counterpart male subjects who participated in a prior study. The total clearance of methylprednisolone for the female subjects was 15.6 +/- 5.99 L/h compared to the males with 21.5 +/- 8.67 L/h (P <.05). When normalized for total or lean body weight, no significant difference was noted (P =.614). A 3-fold interpatient variation in weight-adjusted clearance was noted for female subjects. Dose-normalized methylprednisolone a AUC was greater in women (66.1 +/- 19.8 ng*h/mL) than men (46.4 +/- 19.7 ng*h/mL) (P =.174). Total cortisol AUC was not different between groups (P =.599). Despite chronic steroid therapy, 9 of 13 women had a normal cortisol profile and an ACTH AUC of 299 +/- 102 pg*h/mL. It was concluded that methylprednisolone clearance in women was significantly slower compared to men. When drug clearance was normalized for total and lean body weight, no gender difference was noted. These findings are in contrast to prior data indicating a more rapid methylprednisolone clearance in healthy women. These findings suggest that doses of glucocorticoids should be prescribed on a milligram/kilogram basis instead of empiric dosing schedules.

Hormonal control of inflammatory responses

Almost any stage of inflammatory and immunological responses is affected by hormone actions. This provides the basis for the suggestion that hormones act as modulators of the host reaction against trauma and infection. Specific hormone receptors are detected in the reactive structures in inflamed areas and binding of hormone molecules to such receptors results in the generation of signals that influence cell functions relevant for the development of inflammatory responses. Diversity of hormonal functions accounts for recognized pro- and anti-inflammatory effects exerted by these substances. Most hormone systems are capable of influencing inflammatory events. Insulin and glucocorticoids, however, exert direct regulatory effects at concentrations usually found in plasma. Insulin is endowed with facilitatory actions on vascular reactivity to inflammatory mediators and inflammatory cell functions. Increased concentrations of circulating glucocorticoids at the early stages of inflammation results in downregulation of inflammatory responses. Oestrogens markedly reduce the response to injury in a variety of experimental models. Glucagon and thyroid hormones exert indirect anti-inflammatory effects mediated by the activity of the adrenal cortex. Accordingly, inflammation is not only merely a local response, but a hormone-controlled process.

Autoimmune hyperthyroidism due to secondary adrenal insufficiency: resolution with glucocorticoids

OBJECTIVE

To describe the course of autoimmune hyperthyroid disease in a patient with corticotropin (ACTH) deficiency treated with glucocorticoids.

METHODS

We report the clinical presentation, laboratory data, imaging studies, and management of a patient with weight loss, fatigue, apathy, hallucinations, and arthritis.

RESULTS

Autoimmune hyperthyroidism (positive thyroperoxidase and thyroglobulin antibodies and borderline positive thyrotropin receptor antibody) was diagnosed in a 71-year-old woman. New psychotic symptoms prompted brain magnetic resonance imaging, which revealed a partially empty sella. Undetectable morning cortisol, undetectable ACTH, and failure to stimulate cortisol with synthetic ACTH (cosyntropin 250 mcg) secured the diagnosis of long-standing secondary adrenal insufficiency. Hydrocortisone replacement improved the patient's symptoms, resolved the thyroid disease, and decreased thyroid antibody titers. In retrospect, the patient recalled severe postpartum hemorrhage requiring blood transfusion at age 38 years. A Sheehan event probably occurred 33 years before the patient presented with corticotropin deficiency. Hyperthyroidism accelerated cortisol metabolism and provoked symptoms of adrenal insufficiency.

CONCLUSIONS

The hypocortisolemic state may precipitate hyperimmunity and autoimmune thyroid disease. Rapid resolution of hyperthyroidism and decreased thyroid antibody titers with glucocorticoid treatment support this hypothesis.

Assessment of the hypothalamic-pituitary-adrenal axis in critical illness

Cortisol is the main corticosteroid secreted from the human adrenal cortex, and it has a crucial role for survival in stressful conditions. An adequate increase in levels of cortisol helps patients to cope with the severity of the disease in the acute phase of critical illness. Either higher or lower than expected cortisol levels were found to be related to increased mortality. Prolonged activation of the hypothalamic-pituitary-adrenal (HPA) axis can result in hypercortisolemia or hypocortisolemia; both can be detrimental to recovery from critical illness. Primary and secondary adrenal insufficiency, relative adrenal insufficiency, tissue resistance to glucocorticoids, adrenocorticotrophic hormone deficiency and immune-mediated inhibition of the HPA axis can be the cause of the impairment of the secretion or action of cortisol in critically ill patients. Recently, some authors offered the term 'critical illness-related corticosteroid insufficiency' to better point out the relative adrenal insufficiency that is seen during critical illness. Patients with critical illness-related corticosteroid insufficiency not only have insufficient circulating cortisol but also have impaired cellular utilization of cortisol. In this article, how adrenal dysfunction presents in critical illness and how appropriate diagnosis and management can be achieved in the critical care setting will be discussed.

Enhanced proinflammatory cytokine response to bacterial lipopolysaccharide in the adult male rat after either neonatal or prepubertal ablation of biological testosterone activity

A sex steroid-dependent modulation of the immune function in mammals is accepted, and evidence suggests that while estrogens enhance, androgens inhibit the immune response. The aim of this study was to explore in the adult male rat the effect of either neonatal flutamide (FTM) treatment or prepubertal orchidectomy (ODX) on endocrine markers in the basal condition and peripheral tumor necrosis factor alpha (TNFα) levels during inflammatory stress. For these purposes, (1) 5-day-old male rats were subcutaneously injected with either sterile vehicle alone or containing 1.75 mg FTM, and (2) 25-day-old male rats were sham operated or had ODX. Rats were sacrificed (at 100 days of age) in the basal condition for determination of peripheral metabolite levels. Additional rats were intravenously injected with bacterial lipopolysaccharide (LPS; 25 μg/kg body weight, i.v.) and bled for up to 4 h. Data indicate that (1) ODX increased peripheral glucocorticoid levels and reduced those of testosterone, whereas FTM-treated rats displayed low circulating leptin concentrations, and (2) LPS-induced TNFα secretion in plasma was significantly enhanced in the FTM and ODX groups. Our study supports that neonatal FTM treatment affected adiposity function, and adds data maintaining that androgens have a suppressive role in proinflammatory cytokine release in plasma during inflammation.

Methylenedioxymethamphetamine ('Ecstasy')-induced immunosuppression: a cause for concern?

Methylenedioxymethamphetamine (MDMA; 'Ecstasy') is a ring-substituted amphetamine and a popular drug of abuse. In addition to ability to induce euphoria, MDMA abuse is associated with a range of acute and long-term hazardous effects. This paper is focused on once such adverse effect: its ability to negatively impact on functioning of the immune system. Research demonstrates that MDMA has immunosuppressive properties, with both innate and adaptive arms of the immune system being affected. The ability of MDMA to suppress innate immunity is indicated by impaired neutrophil phagocytosis and reduced production of dendritic cell/macrophage-derived pro-inflammatory cytokines including tumour necrosis factor-alpha, interleukin (IL)-1beta, IL-12 and IL-15. MDMA also suppresses innate IFN-gamma production, and considering the role of IFN-gamma in priming antigen-presenting cells, it is not surprising that MDMA reduces MHC class II expression on dendritic cells and macrophages, and inhibits co-stimulatory molecule expression. Paradoxically, studies demonstrate that MDMA elicits pro-inflammatory actions in the CNS by activating microglia, the resident innate immune cells in the brain. In terms of adaptive immunity, MDMA reduces circulating lymphocyte numbers, particularly CD4(+) T-cells; suppresses T-cell proliferation; and skews cytokine production in a Th(2) direction. For the most part, the immunosuppressive effects of MDMA cannot be attributed to a direct action of the drug on immune cells, but rather due to the release of endogenous immunomodulatory substances. In this regard, peripheral beta-adrenoceptors and cholinergic receptors have been shown to mediate some immunosuppressive effects of MDMA. Finally, we discuss emerging evidence indicating that MDMA-induced immunosuppression can translate into significant health risks for abusers.

Understanding stress-induced immunosuppression: exploration of cytokine and chemokine gene profiles in chicken peripheral leukocytes

At present, the poultry meat and egg industry has gained a lot of ground, being viewed as a provider of a healthy alternative to red meat and other protein sources. If this trend is to be maintained, solutions must be found to improve resistance of chickens to disease, which often is weakened by stressful conditions. In poultry, stress-induced immunosuppression is manifested by failures in vaccination and increased morbidity and mortality of flocks. Currently, several modern cellular and molecular approaches are being used to explore the status of the immune system during stress and disease. It is likely that these new techniques will lead to the development of new strategies for preventing and controlling immunosuppression in poultry. Using quantitative reverse transcription-PCR assays, a broad spectrum of cytokine, chemokine, and their receptor genes can be quantified in birds and then be used as markers to assess the effects of stress on the immune system. Currently, we are investigating immune and endocrine interactions in the chicken, in particular the cells and molecules that are known to be involved in such interactions in mammals. We have evaluated the effects of corticosterone administration in drinking water on peripheral lymphocyte and heterophil cytokine and chemokine gene profiles. In particular, there seems to be effects on cytokine and chemokine mRNA expression levels in both lymphocytes and heterophils, especially expression of the proinflammatory cytokines interleukin (IL)-1beta, IL-6, and IL-18 and chemokines C-C motif, ligand 1 inflammatory (CCLi1); C-C motif, ligand 2 inflammatory (CCLi2); C-C motif, ligand 5 (CCL5); C-C motif, ligand 16 (CCL16); C-X-C motif ligand 1 inflammatory (CXCLi1); and C-X-C motif ligand 2 inflammatory (CXCLi2), which are initially upregulated and are potentially involved in modulating the adaptive immune response. A chronic treatment with corticosterone downregulates proinflammatory cytokines and chemokines, suggesting that the delayed effects of chronic stress can suppress the immune response. Messenger RNA expression levels of transforming growth factor-beta4 (TGF-beta4) are also upregulated in cortisosterone-treated birds. It appears that the balance between T-helper (Th) 1 and Th2/T regulatory cytokine production is altered in conditions associated with significant changes in plasma corticosterone concentration. Experiments are underway to decipher the cytokine and chemokine responses to vaccination and bacterial challenge on the background of stress-induced immunosuppression.

Stress-related endocrinological and psychopathological effects of short- and long-term 50Hz electromagnetic field exposure in rats

It is believed that different electromagnetic fields do have beneficial and harmful biological effects. The aim of the present work was to study the long-term consequences of 50 Hz electromagnetic field (ELF-EMF) exposure with special focus on the development of chronic stress and stress-induced psychopathology. Adult male Sprague-Dawley rats were exposed to ELF-EMF (50 Hz, 0.5 mT) for 5 days, 8h daily (short) or for 4-6 weeks, 24h daily (long). Anxiety was studied in elevated plus maze test, whereas depression-like behavior of the long-treated group was examined in the forced swim test. Some days after behavioral examination, the animals were decapitated among resting conditions and organ weights, blood hormone levels as well as proopiomelanocortin mRNA level from the anterior lobe of the pituitary gland were measured. Both treatments were ineffective on somatic parameters, namely none of the changes characteristic to chronic stress (body weight reduction, thymus involution and adrenal gland hypertrophy) were present. An enhanced blood glucose level was found after prolonged ELF-EMF exposure (p=0.013). The hormonal stress reaction was similar in control and short-term exposed rats, but significant proopiomelanocortin elevation (p<0.000) and depressive-like behavior (enhanced floating time; p=0.006) were found following long-term ELF-EMF exposure. Taken together, long and continuous exposure to relatively high intensity electromagnetic field may count as a mild stress situation and could be a factor in the development of depressive state or metabolic disturbances. Although we should stress that the average intensity of the human exposure is normally much smaller than in the present experiment.

"Relative" adrenal insufficiency in critical illness

OBJECTIVE

To present a recommended approach to the problem of "relative" adrenal insufficiency (RAI) in the intensive care unit (ICU).

METHODS

We examine historical data that support the traditional concepts of adrenal insufficiency and the idea that the increase in cortisol secretion during stress is needed to survive the stress. The controversial use of treatment with glucocorticoids (GCs) in patients with sepsis and septic shock in the ICU (and thus survival benefit) is also briefly discussed.

RESULTS

During the past decade, the concept of RAI as the failure of cortisol secretion to increase in response to stress to sustain the patient through that stress has gained strength. In some studies, it has been suggested that as many as 75% of patients in an ICU setting have RAI. Experimental support for the concept is not possible because there is no clinically useful laboratory measure of GC action. Therefore, diagnosis is generally based on interpretation of the cosyntropin stimulation test.

CONCLUSION

The best clinical judgment should always guide interpretation of any test results, and sharp categorization of patients on the basis of a single cutoff criterion should be avoided. Overall, the concept of RAI has no clinical utility. In these cases, administration of GCs adds cost without benefit and with increased risk.

Negative relationship between expression of glucocorticoid receptor alpha and disease activity: glucocorticoid treatment of patients with systemic lupus erythematosus

OBJECTIVE

Glucocorticoid receptor alpha (GRalpha) is crucial for glucocorticoids (GC) to carry out their physiological and pharmacological roles. Studies have shown the disorder of GR-GC systems in autoimmune diseases. Our study was performed to test the relationship between GRalpha expression and disease activity of systemic lupus erythematosus (SLE).

METHODS

The responses of 55 patients with SLE to GC were screened. We examined GRalpha mRNA and protein expression in peripheral blood mononuclear cells from SLE patients and healthy volunteers by reverse transcriptase-polymerase chain reaction and Western blotting.

RESULTS

Expression of GRalpha in patients with SLE was lower than that in controls (p < 0.05). Expression of GRalpha obviously decreased after administration of GC in the steroid-sensitive group with SLE (p < 0.05). Expression of GRalpha was negatively correlated with SLE Disease Activity Index scores in the steroid-sensitive group with SLE.

CONCLUSION

The expression of GRalpha in patients with SLE was low and there was a negative correlation between GRalpha expression and disease activity; these findings might provide insight into the pathogenesis of SLE and help to screen whether the patient is sensitive to GC treatment. (Heilungkiang Provincial Health Department Guiding Projects Funding. Trial registration No. 2006-094.).

Neonatal stress modulates sickness behavior

The quality of the early environment, especially during the neonatal period, influences the development of individual differences in resistance to stress and illness in adulthood. A previous study demonstrated that neonatal stress augmented proinflammatory cytokine expression and viral replication in influenza virus-infected adult mice. The goal of the following study was to examine the lifelong effects of neonatal stress on the behavioral response to an immune challenge. Neonatal stress consisted of separating mouse pups from their dams (maternal separation, MSP) at critical points of their development. In the first study, pups were separated from the dam daily for 6h between postnatal day 1 and 14. As adults, these mice were infected with influenza A/PR8 virus. In a second study, a similar paradigm of MSP was employed, and as adults mice were injected with lipopolysaccharide (LPS) (ip). In a third study pups were separated from the dam for 24h on postnatal day 4 or 9. As adults, these mice received ip injections of LPS. In all three studies, changes in body weight, food and sweet solution consumption were examined following immune challenge. As previously described, activation of the immune system using influenza virus infection or LPS administration resulted in sickness behavior that consisted of body weight loss, anorexia and reduced consumption of a sweet solution. Furthermore, neonatal stress induced more rapid kinetics of sickness behavior and augmented several aspects of these symptoms. Together with previous studies, these findings suggest that neonatal stress disrupted the regulation of innate resistance to an immune challenge resulting in enhanced immunological and behavioral responses to immune activation. Thus, long lasting effects of early stress events may be the basis for individual differences in health and susceptibility to disease.

Social buffering of the stress response: diversity, mechanisms, and functions

Protracted or repeated activation of the hypothalamic-pituitary-adrenocortical (HPA) system is associated with a variety of physical and psychological pathologies. Studies dating back to the 1970s have documented many cases in which the presence of a social companion can moderate HPA responses to stressors. However, there also are many cases in which this "social buffering" of the HPA axis is not observed. An examination of the literature indicates that the nature of the relationship between individuals is crucial in determining whether or not social buffering of the HPA response will occur. Other factors that affect social buffering, either directly or by influencing the social relationship, include the social organization of the species, previous experience, gender, integration into a social unit, and the developmental stage at which individuals are examined. Current evidence suggests that social buffering involves mechanisms acting at more than one level of the CNS. It is suggested that, in addition to promoting health, social buffering may have evolved to direct the establishment of social relationships, and to facilitate developmental transitions in social interactions appropriate for different life stages.

Psychosocial stress and liver disease status

"Psychosocial stress" is an increasingly common concept in the challenging and highly-demanding modern society of today. Organic response to stress implicates two major components of the stress system, namely the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system. Stress is anamnestically reported by patients during the course of disease, usually accompanied by a decline in their overall health status. As the mechanisms involving glucocorticoids and catecholamines have been deciphered, and their actions on immune cell function deeper understood, it has become clear that stress has an impact on hepatic inflammatory response. An increasing number of articles have approached the link between psychosocial stress and the negative evolution of hepatic diseases. This article reviews a number of studies on both human populations and animal models performed in recent years, all linking stress, mainly of psychosocial nature, and the evolution of three important liver-related pathological entities: viral hepatitis, cirrhosis and hepatocellular carcinoma.

Testosterone treatment diminishes sickness behavior in male songbirds

Males of many vertebrate species are typically more prone to disease and infection than female conspecifics, and this sexual difference is partially influenced by the immunosuppressive properties of testosterone (T) in males. T-induced immunosuppression has traditionally been viewed as a pleiotropic handicap, rather than an adaptation. Recently, it has been hypothesized that suppression of sickness behavior, or the symptoms of infection, may have adaptive value if sickness interferes with the expression of T-mediated behaviors important for male reproductive success. We conduct a classic hormone replacement experiment to examine if T suppresses sickness behavior in a seasonally-breeding songbird, Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii). Triggered experimentally by bacterial lipopolysaccharide (LPS), sickness behavior includes decreased activity, anorexia, and weight loss. Gonadectomized (GDX) males that were treated with silastic implants filled with T exhibited suppression of behavioral and physiological responses to LPS compared to GDX and sham-GDX controls given empty implants. Sickness responses of control groups were statistically indistinguishable. T-implanted birds had significantly higher plasma T than control groups and levels were within the range associated with aggressive interactions during male-to-male contests. These findings imply that suppression of sickness behavior could occur when T is elevated to socially-modulated levels. Alternatively, it is possible that this suppressive effect is mediated through a stress-induced mechanism, as corticosterone levels were elevated in T-implanted subjects compared to controls. We propose that males wounded and infected during contests may gain a brief selective advantage by suppressing sickness responses that would otherwise impair competitive performance. The cost of immunosuppression would be manifested in males through an increased susceptibility to disease, which is presumably offset by capitalizing upon limited reproductive opportunities.

Assessing the immune state of dogs suffering from pituitary gland dependent hyperadrenocorticism by determining changes in peripheral lymphocyte subsets

In order to evaluate the immune state of dogs suffering from pituitary-dependent hyperadrenocorticism (PDH), peripheral lymphocyte subsets were examined. Twenty seven PDH dogs and eight healthy control dogs were used in the current study. Eight healthy dogs served as the control group. Twenty seven PDH dogs were categorized into 4 groups based on their post serum cortisol concentrations by ACTH stimulation test: 2-5, excellent control (n = 8); 5-20, fair control (n = 7); >20, poor control (n = 4); and untreated (n = 8). Cell counts were executed with white blood cells (WBC), lymphocytes, CD3(+) (T lymphocytes), CD4(+) (Helper T lymphocytes), CD8(+) (Cytotoxic T lymphocytes), CD21(+) (B lymphocytes) cells in addition to calculating CD4(+)/CD8(+) ratio. Results indicated a significant difference in lymphocyte numbers and lymphocyte subset populations (CD3(+), CD4(+), CD8(+), and CD21(+) cells) between PDH and control dogs. Moreover, comparison of the PDH groups (excellent control; fair control; poor control; untreated) demonstrated that all groups had a significant decrease in lymphocytes numbers (CD3(+), CD4(+) and CD21(+) cell counts) as compared to control group. Meanwhile, no significant differences were observed in WBC counts and CD4(+)/CD8(+) ratio between groups. Furthermore, lymphocyte subset distribution in excellent control PDH dogs without concurrent disease (n = 4) better resembled that of control dogs as compared to PDH dogs with concurrent disease (n = 4). PDH dogs may be suffering from an immuno-depressed state as evidenced by significant differences in lymphocyte subset populations. Furthermore, treatment of both PDH and concurrent disease might improve lymphocyte subset distribution.

Effect of naproxen on the hypothalamic-pituitary-adrenal axis in healthy volunteers

AIM

To study the effect of the nonsteroidal anti-inflammatory drug naproxen on the activity of the hypothalamic-pituitary-adrenal (HPA) axis in healthy volunteers.

METHODS

A double-blind, randomized study in two groups of 20 healthy volunteers was performed. The activity of the HPA axis was measured before and after the use of naproxen or placebo during a period of 2 weeks. Basal plasma adrenocorticotropic hormone (ACTH) and cortisol, 24-h urinary cortisol, and circadian cortisol rhythm in saliva were determined. Plasma ACTH and cortisol were also measured during submaximal physical exercise.

RESULTS

There were no significant differences between the placebo and naproxen groups in basal plasma ACTH [09.00 h 3.1 pmol l(-1), 95% confidence interval (CI) 2.0, 4.2, and 2.8 pmol l(-1), 95% CI 1.9, 3.7, respectively], cortisol levels (09.00 h 0.45 micromol l(-1), 95% CI 0.39, 0.51, and 0.40 micromol l(-1), 95% CI 0.35, 0.44, respectively), 24 h urinary cortisol excretion (67.5 nmol 24 h(-1), 95% CI 54.3, 80.7, and 86.8 nmol 24 h(-1), 95% CI 54.4, 119.2, respectively), circadian cortisol rhythm measured in salivary samples, or ACTH and cortisol concentrations after physical exercise. After the use of placebo or naproxen for 2 weeks, no significant change in any of the parameters occurred (ACTH 09.00 h 3.0 pmol l(-1), 95% CI 2.0, 3.9, and 3.0 pmol l(-1), 95% CI 2.2, 3.8, respectively; cortisol 09.00 h 0.45 micromol l(-1), 95% CI 0.37, 0.52, and 0.39 micromol l(-1), 95% CI 0.34, 0.44, respectively; cortisol urine 79.5 nmol 24 h(-1), 95% CI 59.5, 99.4, and 81.7 nmol 24 h(-1), 95% CI 64.0, 99.4, respectively), and no significant differences were found in these parameters between the placebo and naproxen groups.

CONCLUSIONS

The use of naproxen does not influence the activity of the HPA axis in healthy volunteers under basal circumstances or in response to physical stress.

Inflammatory cytokines regulate glycoprotein subunit beta5 of thyrostimulin through nuclear factor-kappaB

Thyrostimulin is a heterodimeric hormone comprised of two glycoprotein hormone subunits, namely glycoprotein hormone subunit alpha2 and glycoprotein hormone subunit beta5 (GPB5). Immunological studies have revealed that both subunits colocalize in human pituitary corticotroph cells. Although recombinant thyrostimulin protein selectively activates the TSH receptor and has thyrotropic activity in rats, its biological functions have not been clarified. To explore the physiological regulators for the GPB5, the 5'-flanking region of the GPB5 coding sequence up to 3-kb upstream was analyzed by luciferase reporter assays. We found that nuclear factor-kappaB (NF-kappaB) markedly activated GPB5 transcription. Disruption of the putative NF-kappaB-binding motifs in the GPB5 5'-flanking region silenced the GPB5 activation by p65. Chromatin immunoprecipitation assays revealed that recombinant p65 bound to the predicted NF-kappaB-binding sites. Because NF-kappaB is known to associate with acute phase inflammatory cytokines, we examined whether TNFalpha or IL-1beta could regulate GPB5. Both these cytokines activated GPB5 transcription by 2- to 3-fold, and their effects were abolished by the addition of MG132, a NF-kappaB inhibitor. Our results suggest that inflammatory cytokines positively regulate thyrostimulin through NF-kappaB activation.

[Repercussions and management of perioperative hyperglycemia in cardiac surgery]

Surgery produces a neuroendocrine stress response that affects resistance to insulin, reduces insulin secretion, and increases the release of glucose from the liver. This situation can trigger hyperglycemia in both diabetics and nondiabetics. Hyperglycemia has been linked to an increase in the morbidity and mortality among patients who undergo cardiac surgery, and the benefits of correcting hyperglycemia in this setting by means of intensive insulin therapy are well documented. This review discusses various aspects of hyperglycemia, particularly the evidence supporting stricter control of this condition in patients undergoing cardiac surgery. Furthermore, based on the available data and recommendations, and our clinical experience, we suggest therapeutic strategies to improve the control of hyperglycemia in these patients.

Critical illness-related corticosteroid insufficiency

The diagnosis of adrenal failure and the indications for corticosteroid therapy in critically ill patients are controversial. This controversy is fueled by the complexity of the issues and the paucity of data from high quality clinical trials. Nevertheless, while the use of high-dose corticosteroids in patients with severe sepsis and ARDS failed to improve outcome and was associated with increased complications, an extended course of stress-dose corticosteroids has been reported to increase the occurrence of ventilator-free days and survival in select groups of ICU patients. These patients typically have an exaggerated proinflammatory response. Until recently the exaggerated proinflammatory response that characterizes critically ill patients with systemic inflammation has focused on suppression of the hypothalamic-pituitary-adrenal axis and adrenal failure. However, experimental and clinical data suggest that glucocorticoid tissue resistance may also play an important role. This complex syndrome is referred to as critical illness-related corticosteroid insufficiency (CIRCI) and is defined as inadequate corticosteroid activity for the severity of the illness of a patient. The paper reviews cortisol physiology, CIRCI, and the role of corticosteroid therapy in critically ill patients.

Cushing's syndrome: aftermath of the cure

Cushing's syndrome (CS) is a chronic and systemic disease caused by endogenous or exogenous hypercortisolism, associated with an increase of mortality rate due to the clinical consequences of glucocorticoid excess, especially cardiovascular diseases. After cure, usually obtained by the surgical removal of the tumor responsible for the disease, the normalization of cortisol secretion is not constantly followed by the recovery of the clinical complications developed during the active disease, and it is often followed by the development of novel clinical manifestations induced by the fall of cortisol levels. These evidences were mostly documented in patients with pituitary-dependent CS, after surgical resection of the pituitary tumor. Indeed, despite an improvement of the mortality rate, metabolic syndrome and the consequent cardiovascular risk have been found to partially persist after disease remission, strictly correlated to the insulin resistance. Skeletal diseases, mainly osteoporosis, improve after normalization of cortisol levels but require a long period of time or the use of specific treatment, mainly bisphosphonates, to reach the normalization of bone mass. A relevant improvement or resolution of mental disturbances has been described in patients cured from CS, although in several cases, cognitive decline persisted and psychological or psychiatric improvement was erratic, delayed, or incomplete. On the other hand, development or exacerbation of autoimmune disorders, mainly thyroid autoimmune diseases, was documented in predisposed patients with CS after disease remission. The totality of these complications persisting or occurring after successful treatment contribute to the impairment of quality of life registered in patients with CS after disease cure.

First Observation of an Hashimoto Thyroiditis-Like Disease in Horses from Eastern Europe: Histopathological and Immunological Findings

Among 622 slaughtered horses from eastern Europe, 156 thyroid glands were selected on the basis of macroscopic alterations (e.g., determination of volume and weight). In the 80% of these thyroids, microscopic alterations consistent with a diagnosis of Hashimoto thyroiditis-like disease were found. In particular, a subverted architecture of the thyroid gland with colloid rarefaction, lymphocytic infiltration, and fibrosis was noted. The confirmation of the histopathological diagnosis of an equine Hashimoto thyroiditis-like disease was provided by the increased serum concentration of thyroglobulin, of antithyroglobulin, and of antithyroid peroxidase autoantibodies. Despite evidence consistent with an Hashimoto thyroiditis-like disease in eastern European horses, the etiopathogenesis of this autoimmune disorder deserves further investigation. In this respect, in some horses histopathological alterations in the pituitary gland may suggest an as-yet-unidentified disorder within the hypothalamus-pituitary adrenal axis associated with Hashimoto thyroiditis.

Diurnal variation in the cellular and humoral immune responses of Japanese quail: role of melatonin

Experiments were conducted to determine if diurnal variations occur in the cellular and humoral immune responses of sexually mature, male Japanese quail and if this diurnal variation is mediated by the daily rhythm of melatonin. In Experiment 1, quail were exposed to LD 12:12 light-dark cycles and immune responses were measured in response to a single antigenic challenge given to different groups every 4h over a 24h period. Diurnal changes occurred in both the cellular and humoral immune responses. The cellular response was higher during the light phase than during the dark phase whereas the opposite was true for the humoral immune response. Experiment 2 was designed to determine if melatonin mediated these diurnal immune responses. Quail were maintained in continuous light (LL) to suppress endogenous melatonin production and half of them were given melatonin in the drinking water for 12h each day for 2 weeks. Contrary to control quail, significant daily variations occurred in both the humoral and cellular immune responses of birds given melatonin. As in Experiment 1, the cellular and humoral immune responses were out of phase with one another, with the humoral response being maximal when melatonin was present. We may conclude that there exists a melatonin dependent diurnal variation in both cellular and humoral immune responses of quail. The responses were inverse to one another during the daily light-dark cycle with the cellular response being maximal during the daily light period and the humoral response being maximal during the daily dark period.

Fasting differentially modulates the immunological system: its mechanism and sex difference

The immunological properties and hormonal metabolism in rodents are affected by physical and psychological stress more strongly in males than in females. To elucidate the mechanism and physiological significance of the sex difference in the susceptibility of animal to stresses, changes in the immunological system in plasma and intestine and hormonal status in plasma were compared among 8-week-old male and female ICR mice before and after fasting. During the fasting of animals, the expression of immunoglobulin A in intestinal mucosa, and cortisol, interleukin-10 and interferon-gamma in plasma increased. These changes occurred more apparently in males than in females. Under identical conditions, the plasma levels of testosterone decreased markedly with concomitant occurrence of apoptosis in the testis, while the plasma levels of estradiol decreased calmly, and no appreciable apoptosis occurred in the ovary. These results indicate that testosterone enhances the stress-induced modulation of the immune system by some mechanism that was antagonized by estradiol.

Latitudinal variation of immune defense and sickness behavior in the white-crowned sparrow (Zonotrichia leucophrys)

There is a general trend that parasitism risk declines as latitude increases. Host populations breeding at high latitudes should therefore invest less in costly immune defenses than populations breeding in temperate or tropical zones, although it is unknown if such an effect is mediated by environmental (photoperiodic) or genetic factors or both. Acquired immune function (humoral, cell-mediated) and behavioral sickness responses to lipopolysaccharide (LPS; mimics bacterial infection) were assessed in two subspecies of white-crowned sparrow (Zonotrichia leucophrys) that breed at different latitudes in western North America. Zonotrichia l. gambelii (GWCS) is a high-latitude breeder (47-68 degrees N) while Z. l. pugetensis (PWCS) breeds at temperate latitudes (40-49 degrees N). Captive males of each subspecies were acclimated to (1) a short day (non-breeding) photoperiod (8L:16D), (2) the breeding photoperiod of PWCS (16L:8D), or (3) the breeding photoperiod of GWCS (20L:4D). Photoperiod was manipulated because shorter day lengths may enhance immune function. In support of a genetic effect, humoral responses to diphtheria-tetanus vaccination were significantly higher in PWCS compared to GWCS, regardless of photoperiod. There were no differences in cell-mediated responses to phytohemagglutinin (PHA) between subspecies or among photoperiods. For sickness responses to LPS, a significant interaction between photoperiod and subspecies was found, with long day GWCS producing stronger sickness responses (losing more weight, eating less) than short day GWCS and PWCS on all day lengths. However, these effects were influenced by photoperiodic changes in body condition. In conclusion, we find evidence for genetic control of immune responses across latitude, but no support for environmental (photoperiodic) regulation.

Pain, disability and coping reflected in the diurnal cortisol variability in patients scheduled for lumbar disc surgery

BACKGROUND

Symptoms of lumbar disc herniation can be induced by both mechanical compression of the nerve roots and by biochemical irritants from the disc tissues. Proinflammatory cytokines, as well as stress are potent stimulators of the hypothalamic-pituitary-adrenal axis, reflected in enhanced release of cortisol from the adrenal cortex. Altered cortisol production is also associated to behaviour and coping patterns. The aim of the present study was to explore the relation between pain, physical function, psychosocial factors and quality of life to the diurnal cortisol variability, in patients with lumbar disc herniation.

METHOD

This study had a cross-sectional design. Forty-two patients with lumbar disc herniation, verified by magnetic resonance imaging and a clinical examination by an orthopaedic surgeon, were included in the study. All patients were scheduled for disc surgery. The diurnal cortisol variability was examined before surgery. The patients were dichotomised into two groups based on low or high diurnal cortisol variability. Pain, disability, work related stress, quality of life, coping and fear avoidance beliefs, were estimated by standardised questionnaires.

RESULTS

The low diurnal cortisol variability group was distinguished by a higher median score regarding leg pain at activity and significantly more disability (p<0.05). The patients with a low diurnal cortisol variability had significantly lower coping self-statement scores, but higher pain coping catastrophising scores (p<0.05).

CONCLUSION

Patients with lumbar disc herniation and a low diurnal cortisol variability had lower physical function, perceived lower possibilities of influencing their pain, and were more prone to catastrophise than patients with lumbar disc herniation and a high diurnal cortisol variability.

Mechanisms and clinical consequences of critical illness associated adrenal insufficiency

PURPOSE OF REVIEW

Adrenal insufficiency is being diagnosed with increasing frequency in critically ill patients. There exists, however, much controversy in the literature as to the nature of this entity, including its pathophysiology, epidemiology, diagnosis and treatment. The review summarizes our current understanding of the causes and consequences of adrenal insufficiency in critically ill patients.

RELEVANT FINDINGS

Activation of the hypothalamic-pituitary-adrenal axis with the production of cortisol is a fundamental component of the stress response and is essential for survival of the host. Dysfunction of the hypothalamic-pituitary-adrenal axis with decreased glucocorticoid activity is being increasingly recognized in critically ill patients, particularly those with sepsis. This condition is best referred to as 'critical illness-related corticosteroid insufficiency'. Critical illness-related corticosteroid insufficiency may occur due to dysfunction at any point in the hypothalamic-pituitary-adrenal axis including tissue glucocorticoid resistance. Critical illness-related corticosteroid insufficiency leads to an exaggerated proinflammatory response with increased tissue injury and organ dysfunction.

SUMMARY

Critical illness-related corticosteroid insufficiency is common in critically ill patients, particularly those with sepsis. Supplemental corticosteroids may restore the balance between the pro-and anti-inflammatory mediators in patients with severe sepsis, septic shock and acute respiratory distress syndrome, and thereby improve the outcome of patients with these conditions.

Current controversy related to glucocorticoid and insulin therapy in the intensive care unit

OBJECTIVE

To review the controversy related to the widespread use of intensive insulin treatment (IIT) to maintain normoglycemia and of glucocorticoid replacement therapy in patients with sepsis in the intensive care unit (ICU).

METHODS

We performed a MEDLINE search of the literature using a combination of words (critical/intensive care, endocrinology/endocrine, glucocorticoid/adrenal, insulin) to identify original studies and reviews on glucocorticoid therapy and IIT in the ICU.

RESULTS

Glucocorticoid replacement therapy is advocated for patients with sepsis who have relative adrenal insufficiency. The current definition of relative adrenal insufficiency is poorly supported, and validated endocrine criteria that consistently identify ICU patients likely to benefit from glucocorticoid therapy are not yet available. IIT benefits postoperative patients at high risk of infection and patients who remain in the ICU more than 3 days. Potential harm caused by early IIT administration in medical ICU patients remains controversial. The role of early nutritional supplementation in major studies about IIT is largely unexplored. Improvements in insulin infusion protocols are needed to reduce the risk of hypoglycemia related to IIT.

CONCLUSION

Endocrine therapy in the ICU is entering a new era. Controversies remain related to glucocorticoid and insulin therapy even as interest in new, and old, endocrine therapies is being revived.

Mechanisms mediating the effects of cytokines on neuroendocrine functions in the rat

Exposure to an antigen causes significant endocrine changes, some of which in turn affect immune functioning. Proteins produced by activated immune cells, cytokines, act as messengers between the immune and the endocrine systems, and convey to the brain the occurrence of immune activation. We have investigated the ability of interleukin 1 (IL-1) alpha and beta to alter endocrine functioning in the adult rat. Acute peripheral injection of IL-1 alpha or beta causes dose-dependent increases in plasma adrenocorticotropic hormone (ACTH) and corticosterone secretion. These changes are primarily dependent upon increased release of corticotropin-releasing factor (CRF) into the portal circulation, and recent studies have indicated that the paraventricular nucleus (PVN) of the hypothalamus is the main source of this CRF. This conclusion is based on our finding that intravenous injection of IL-1 increases CRF biosynthesis in the PVN, and that lesion of this hypothalamic area interferes with IL-1's stimulatory action on ACTH secretion. Indomethacin partially reverses the effect of IL-1, suggesting that increased prostaglandin synthesis plays some part in this activation. Administration of IL-1 beta into the brain, but not into the general circulation, interferes with secretion of luteinizing hormone (LH) and ovulation through mechanisms involving endogenous opiates. Because neither CRF antagonists, nor lesions of the PVN, alter the inhibitory effect of IL-1 on LH release, CRF perikarya in the PVN do not appear to be involved in this phenomenon. Central administration of IL-1 beta strongly increases c-Fos immunoreactivity in the PVN, mainly within CRF neurons. Infusion of IL-1 beta into the PVN does not induce measurable changes in release of gonadotropin-releasing hormone (GnRH), but infusion of IL-1 directly into the median preoptic area (MPOA), a region rich in GnRH perikarya, markedly decreases GnRH secretion in rats bearing a push-pull cannula in the median eminence. Furthermore, central administration of IL-1 beta during the critical phase of pro-oestrus (1600-1930) also inhibits the expression of c-fos in GnRH cell bodies in the MPOA. Thus, we suggest that IL-1 interferes with reproductive functioning through a direct action at the level of the MPOA. These results indicate that circulating cytokines can alter the activity of the hypothalamo-pituitary-adrenal axis by increasing CRF release, probably through both immediate stimulation of CRF terminals within the median eminence and stimulation of CRF synthesis in the PVN. In contrast, cytokine-induced changes in LH and GnRH secretion are mediated through pathways lying primarily beyond the blood-brain barrier.

Expression of corticotropin-releasing factor mRNA in response to stress

The corticotropin-releasing factor (CRF)-containing neurons of the parvocellular division of the hypothalamic paraventricular nucleus play a pivotal role in the regulation of the hypothalamo-pituitary-adrenal axis. We have studied the regulation of these neurons in the conscious rat using the technique of quantitative in situ hybridization histochemistry. Corticosteroid feedback reduces CRF mRNA levels in a dose-dependent manner, although even prolonged administration of very high doses cannot abolish CRF transcripts completely. Both physical and psychological stressors produce a robust and readily reproducible increase in CRF mRNA. These responses cannot be prevented by changes in circulating corticosteroids--a similar magnitude of response occurs with high basal levels in the adrenalectomized animal and with low basal levels during treatment with supraphysiological doses of glucocorticoid. Alterations in CRF mRNA levels in response to stress are, however, lost during the physiological condition of lactation, a state known to result in stress hyporesponsiveness, and also after 6-hydroxydopamine lesions to the catecholaminergic innervation of the paraventricular nucleus. We have also studied two conditions of chronic immunological activation of the hypothalamo-pituitary-adrenal axis--adjuvant-induced arthritis and experimental allergic encephalomyelitis. Both of these results in activation of the hypothalamo-pituitary-adrenal axis with increased plasma corticosterone and ACTH, and pituitary pro-opiomelanocortin (POMC) mRNA. Unexpectedly, however, the activation of pituitary corticotrophs does not seem to be a primary result of increased activation of the CRF neurons, which actually show a consistent fall in CRF mRNA.

A rationale for using steroids in the treatment of severe cases of H5N1 avian influenza

Acute hypercytokinaemia represents an imbalance of pro-inflammatory and anti-inflammatory cytokines, and is believed to be responsible for the development of acute respiratory distress syndrome and multiple organ failure in severe cases of avian (H5N1) influenza. Although neuraminidase inhibitors are effective in treating avian influenza, especially if given within 48 h of infection, it is harder to prevent the resultant hypercytokinaemia from developing if the patient does not seek timely medical assistance. Steroids have been used for many decades in a wide variety of inflammatory conditions in which hypercytokinaemia plays a role, such as sepsis and viral infections, including severe acquired respiratory syndromes and avian influenza. However, to date, the results have been mixed. Part of the reason for the discrepancies might be the lack of understanding that low doses are required to prevent mortality in cases of adrenal insufficiency. Adrenal insufficiency, as defined in the sepsis/shock literature, is a plasma cortisol rise of at least 9 μg dl−1 following a 250 μg dose of adrenocorticotropin hormone (ACTH), or reaching a plasma cortisol concentration of >25 μg dl−1 following a 1–2 μg dose of ACTH. In addition, in the case of hypercytokinaemia induced by potent viruses, such as H5N1, systemic inflammation-induced, acquired glucocorticoid resistance is likely to be present. Adrenal insufficiency can be overcome, however, with prolonged (7–10 or more days) supraphysiological steroid treatment at a sufficiently high dose to address the excess activation of NF-κB, but low enough to avoid immune suppression. This is a much lower dose than has been typically used to treat avian influenza patients. Although steroids cannot be used as a monotherapy in the treatment of avian influenza, there might be a potential role for their use as an adjunct treatment to antiviral therapy if appropriate dosages can be determined. In this paper, likely mechanisms of adrenal insufficiency are discussed, drawing from a broad background of literature sources.

Effects of intravenous infusion of lipopolysaccharide on plasma micromineral, magnesium, and cytokine concentrations and serum cortisol concentrations in lactating goats

OBJECTIVE

To assess the effects of various doses of lipopolysaccharide (LPS) administered IV on plasma microminerals, magnesium, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 concentrations and serum cortisol concentrations in lactating goats.

ANIMALS

6 lactating goats.

PROCEDURES

Goats were allotted to 3 LPS-treatment groups: control (0 microg/kg), low LPS (10 microg/kg), and high LPS (50 microg/kg). Rectal temperatures and behaviors of goats were recorded immediately before a 10-minute IV infusion of LPS and at 0.5, 1, 2, 4, 6, 8, and 24 hours after infusion. Blood samples were obtained before IV infusion and at 0.5, 1, 2, 4, 6, 8, and 24 hours after infusion. Plasma zinc, copper, iron, and magnesium concentrations were determined by atomic absorption spectrometry; plasma TNF-alpha and IL-6 concentrations were measured by use of an ELISA; and serum cortisol concentrations were determined by use of a radioimmunoassay.

RESULTS

A monophasic fever developed in low-LPS and high-LPS groups. In the low-LPS and high-LPS group, plasma zinc concentrations decreased at 6 hours after infusion; compared with control groups. Plasma iron concentrations were lower at 24 hours after infusion in low-LPS and high-LPS groups than in the control group. Plasma TNF-alpha and IL-6 concentrations were higher in low-LPS and high-LPS groups than in the control group at 1, 2, and 4 hours after infusion. In low-LPS and high-LPS groups, serum cortisol concentrations increased from 0.5 hours onward and peaked at 1 (high-LPS group) and 2 (low-LPS group) hours after infusion.

CONCLUSIONS AND CLINICAL RELEVANCE

Following IV infusion of LPS, the immune system is activated, which might affect micromineral homeostatic regulation and, subsequently, the metabolic health of lactating goats.

Stressful life events and psychological dysfunctions before the onset of type 1 diabetes mellitus

AIM

To test the hypothesis that stressful life events and psychological dysfunction increase the risk for development of type 1 diabetes mellitus (DM1).

METHOD

A case-control study comprising 105 children with DM1 and 210 controls matched by age +/- 1 year), sex and place of residence. Conditional univariate and multivariate logistic regressions were used to analyze the data.

RESULTS

After adjustment for possible confounders, the following factors were positively related to DM1: parents' job-related issues changed or lost job (odds ratio [OR] 11.5, 95% confidence interval [CI] 1.6-81.8); other severe life events--severe accident, hospitalization or death of close friend, quarrels between parents, war in republics of former Yugoslavia, near-drowning in a pool, falling down, unhurt participant of an accident (OR 68.5, 95% CI 13.5-349.0); other minor life events--conflicts with parents/teacher/neighbors, lost in town, physical attack, failure in competition, penalty, examination, death of pet, presence at lightning strike, thrown out of dwelling (OR 32.7, 95% CI 6.3-169.6); and learning problems (OR 17.5, 95% CI 4.3-71.6).

CONCLUSION

These results support the hypothesis that stressful life events and psychological dysfunctions are associated with DM1.

Hypothalamic-Pituitary-Adrenal Axis Function in Sjogren's Syndrome: Mechanisms of Neuroendocrine and Immune System Homeostasis

To date, evidence suggests that rheumatic diseases are associated with hypofunctioning of the hypothalamic-pituitary-adrenal (HPA) axis. Sjögren's syndrome (SS), the second most common autoimmune disorder, is characterized by diminished lacrimal and salivary gland secretion. To examine HPA axis activity in SS patients, the adrenocorticotropin (ACTH) response to ovine corticotropin-releasing factor (oCRH) was used as a direct measure of corticotrophic function, and the plasma cortisol response to the ACTH released during oCRH stimulation as an indirect measure of adrenal function. Significantly lower basal ACTH and cortisol levels were found in patients with SS and were associated with a blunted pituitary and adrenal response to oCRH compared to normal controls. Fibromyalgia (FM) patients demonstrated elevated evening basal ACTH and cortisol levels and a somewhat exaggerated peak, delta, and net integrated ACTH response to oCRH. A subgroup of SS patients also met the diagnostic criteria for FM and demonstrated a pituitary-adrenal response that was intermediate to SS and FM. These findings suggest not only adrenal axis hypoactivity in SS and FM patients, but also that varying patterns of adrenal and thyroid axes dysfunction may exist in patients with different rheumatic diseases.

Adrenocorticotropic hormone and dehydroepiandrosterone sulfate levels of rheumatoid arthritis patients treated with glucocorticoids

To assess adrenal function with respect to the presence or absence of steroid therapy, we investigated differences in the blood levels of adrenocorticotropic hormone (ACTH) and dehydroepiandrosterone sulfate (DHEAS) in relation to steroid (prednisolone) administration in 123 patients with rheumatoid arthritis (RA). Levels of ACTH and DHEAS were significantly lower in the steroid-treated group than in the non-treated group (ACTH: 11.79 pg/ml vs 27.92 pg/ml) (DHEAS: 418.12 ng/ml vs 883.91 ng/ml) (P<0.0001). We observed no steroid dose-related differences in ACTH levels. However, DHEAS levels showed a slight decrease at a prednisolone dose of 2.5 mg/day, with a significant decrease being observed at a dose of 5 mg/day when statistical adjustments were made for age and sex (P<0.0001). At doses of 7.5 mg/day or greater, DHEAS levels were significantly lower than those for 5 mg/day (P<0.0006). These results suggest that low-dose prednisolone reduces adrenal function in patients with RA. We recommend that doses of prednisolone should be limited to 5 mg/day or less in consideration of adrenal function when treating RA patients. The measurement of ACTH and DHEAS may be useful for evaluating adrenal function in patients with RA.

Plasticity of neuroendocrine-thymus interactions during ontogeny and ageing: role of zinc and arginine

Thymic re-growth and reactivation of thymic functions may be achieved in old animals by different endocrinological or nutritional manipulations such as, (a) treatment with melatonin, (b) implantation of a growth hormone (GH) secreting tumour cell line (GH3 cells) or treatment with exogenous GH, (c) castration or treatment with exogenous luteinizing hormone-releasing hormone (LHRH), (d) treatment with exogenous thyroxin or triiodothyronine, and (e) nutritional interventions such as arginine or zinc supplementation. These data strongly suggest that thymic involution is a phenomenon secondary to age-related alterations in neuroendocrine-thymus interactions and that it is the disruption of these interactions in old age that is responsible for age-associated immune-neuroendocrine dysfunctions. The targets involved in hormones-induced thymic reconstitution may directly or indirectly involve hormone receptors, cytokines, arginine, and a trace element such as zinc, which is pivotal for the efficiency of neuroendocrine-immune network during the whole life of an organism. The effect of GH, thyroid hormones, and LHRH may be due to specific hormone receptors on thymocytes and on thymic epithelial cells (TECs), which synthesize thymic peptides. Melatonin may also act through specific receptors on T-cells. In this context, the role of zinc, which turnover is reduced in old age, is pivotal because of its involvement through zinc fingers in the gene expression of hormone receptors. In addition, the effects of zinc are multifaceted: from the reactivation of zinc-dependent enzymes, to cell proliferation and apoptosis, to cytokines expression and to the reactivation of thymulin, which is a zinc-dependent thymic hormone required for intrathymic T-cell differentiation and maturation as well as for the homing of stem cells into the thymus. Zinc is also required for arginine action, via NO pathway. The role of zinc is therefore crucial in neuroendocrine-thymus interactions. According to data in animals and humans, the above reported endocrinological manipulations (GH, thyroid hormones, and melatonin) or arginine treatment may also act via zinc pool in restoring thymic activity in ageing allowing improvements on peripheral immune efficiency.

The origins of cachexia in acute and chronic inflammatory diseases

The term cachexia originates from the Greek root kakos hexis, which translates into "bad condition," recognized for centuries as a progressive deterioration of body habitus. Cachexia is commonly associated with a number of disease states, including acute inflammatory processes associated with critical illness and chronic inflammatory diseases, such as cancer, congestive heart failure, chronic obstructive pulmonary disease, and human immunodeficiency virus infection. Cachexia is responsible for the deaths of 10%-22% of all patients with cancer and approximately 15% of the trauma deaths that occur from sepsis-induced organ dysfunction and malnutrition days to weeks after the initial traumatic event. The abnormalities associated with cachexia include anorexia, weight loss, a preferential loss of somatic muscle and fat mass, altered hepatic glucose and lipid metabolism, and anemia. Anorexia alone cannot fully explain the development of cachexia; metabolic alterations in carbohydrate, lipid, and protein metabolism contribute to the severe tissue losses. Despite significant advances in our understanding of specific disease processes, the mechanisms leading to cachexia remain unclear and multifactorial. Although complex, increasing evidence from both animal models and clinical studies suggests that an inflammatory response, mediated in part by a dysregulated production of proinflammatory cytokines, plays a role in the genesis of cachexia, associated with both critical illness and chronic inflammatory diseases. These cytokines are further thought to induce an acute phase protein response (APR) and produce the alterations in lipid and carbohydrate metabolism identified as crucial markers of acute inflammation in states of malignancy and critical illness. Although much is still unknown about the etiology of cachexia, there is growing appreciation that cachexia represents the endproduct of an inappropriate interplay between multiple cytokines, neuropeptides, classic stress hormones, and intermediary substrate metabolism.

Role of early stress in the individual differences in host response to viral infection

Early negative life events, especially during the neonatal period, resulted in long lasting, irreversible effects on well being. The goal of the following study was to examine the lifelong effects of neonatal stress on the response to an influenza viral infection. Mouse pups were repeatedly separated from their dams between postnatal days 1-14 (maternal separation, MSP). As adults, these mice were infected with influenza A/PR8 virus and lung cytokine and plasma corticosterone responses to the viral infection were measured. The results indicated that MSP augmented several aspects of the response to infection. First, infection-induced lung proinflammatory cytokine (interleukin (IL)-1, IL-6, and tumor necrosis factor (TNF)-alpha) mRNA expression was higher in MSP mice compared to controls. In addition, MSP augmented infection-induced lung IL-12 and interferon (IFN)-gamma, but had no effect on IL-18 mRNA. Interestingly, MSP-induced increase in IL-1, TNF-alpha and IFN-gamma mRNA expression was evident in females, but not in males. These findings suggest that MSP disrupted the regulation of innate resistance resulting in enhanced cytokine responses in the lungs during an infectious challenge. These changes in host response to the viral infection were accompanied by an increase in viral replication in lungs of MSP mice. Interestingly, influenza-induced corticosterone secretion was blunted in MSP mice, suggesting that the increase in immune reactivity to the virus was due to lack of glucocorticoid feedback control. These data demonstrate that neonatal stress has implications for host resistance to infection throughout life. Thus, long lasting effects of negative life events on health and disease may be the basis for the individual differences in host susceptibility to infection.

The Belgrade childhood diabetes study - comparison of children with type 1 diabetes with their siblings

A case-control study was conducted in Belgrade (about 320,000 inhabitants 0-16 years old) during the period 1994-97, comprising 68 diabetic children (cases) and 68 controls chosen from the siblings of the cases. Analysis using multivariable logistic regression analysis indicated the following independent risk factors for Type 1 diabetes: higher birth order, infections during the 6 months preceding the onset of the disease and stressful events. Out of individual stressful and psychological factors, 'other' stressful events (severe accident or hospitalisation or death of a close friend, conflict with a teacher, death of a pet, failure in competition, quarrel between parents, punishment, physical attack, war in republics of former Yugoslavia and near drowning in the pool) and learning problems were independent risk factor for Type 1 diabetes. The results obtained in this study of siblings supports the hypothesis that environmental factors play a role in the development of Type 1 diabetes.

Interrenal and thyroid development in red drum (Sciaenops ocellatus): effects of nursery environment on larval growth and cortisol concentration during settlement

Red drum settle into shallow seagrass meadows during the larval stage. Day-night cycles in these habitats result in marked diel temperature and dissolved oxygen (DO) cycles, and it is possible that extreme fluctuations influence endocrine development and growth of larvae. Here, we described red drum interrenal and thyroid ontogeny and determine responses to environmental stimuli with special emphasis on settlement to explore possible role of hormones as mediator of directive environmental factors. This study detected an early activation of thyroid and interrenal axis during the yolk-sac phase and a second activation of the thyroid starting at settlement size to the end of the larval period. Whole-body l-thyroxine (T4) and 3-5-3'-triiodo-l-thyronine (T3) showed a sharp decline at the juvenile stage. In contrast, cortisol steadily declines during the larval phase to a minimum before the end of the larval period. Older settlement-size larvae exposed to a strong stimulus increased whole body cortisol. In contrast, new settlers showed a minor cortisol rise suggesting changes on stress responsiveness during the ontogeny of the species. Additionally, settlement-size larvae exposed to various environmentally realistic temperature or DO fluctuations showed no difference in growth compared to fish grown under stable conditions (control). However, growth rate was significantly reduced in DO cycled fish with prolonged exposure to hypoxia. No differences were found in whole-body cortisol levels in the reduced growth treatment groups, suggesting that growth retardation was not related to a cortisol-mediated stress response. In moderate DO and temperature treatment groups, cortisol showed wider fluctuations than control groups during the night time that were not related to stress.

The acute asymmetric effects of hemiovariectomy on testosterone secretion vary along the estrous cycle. The participation of the cholinergic system

The presence of asymmetry in the capacity of the left and right ovaries to secrete testosterone was analyzed by studying the effects of hemiovariectomy along the estrus cycle one hour after surgery. The effects of ether anesthesia on hormone serum levels were also analyzed. Bilateral ovariectomy and the extirpation of the left ovary performed on the day of proestrus resulted in significantly lower testosterone levels. Compared to the anesthetized group, the effects of perforating the peritoneum unilaterally varied according to the day of the estrous cycle and the side of the peritoneum surgery was performed on. Injecting atropine sulfate (ATR) to control or anesthetized rats on D1 resulted in a significant increase of testosterone serum levels. The effects of perforating the peritoneum on testosterone levels depended on the cholinergic innervation and varied along the estrous cycle. Blocking the cholinergic system before performing unilateral or bilateral ovariectomy had different effects depending on the day of the estrous cycle. Testosterone plasma levels increased significantly when surgery was performed on the day of diestrus and dropped when surgery was performed on proestrus. Similar effects were observed when the left adrenal was extirpated from animals with the cholinergic system blocked. The results presented herein support the hypothesis of asymmetry in the ovaries' abilities to secrete steroid hormones, and that the capacity to secrete testosterone varies along the estrous cycle.