Suppressing the Morning Cortisol Rise After Memory Reactivation at 4 A.M. enhances Episodic Memory Reconsolidation in Humans.

Evidence from animal and human research shows that established memories can undergo changes after reactivation through a process called reconsolidation. Alterations of the level of the stress hormone cortisol may provide a way to manipulate reconsolidation in humans. Here, in a double-blind, within-subject design, we reactivated a 3-d-old memory at 3:55 A.M. in sixteen men and four women, immediately followed by oral administration of metyrapone versus placebo, to examine whether metyrapone-induced suppression of the morning cortisol rise may influence reconsolidation processes during and after early morning sleep. Crucially, reactivation followed by cortisol suppression versus placebo resulted in enhanced memory for the reactivated episode tested 4 d after reactivation. This enhancement after cortisol suppression was specific for the reactivated episode versus a non-reactivated episode. These findings suggest that when reactivation of memories is immediately followed by suppression of cortisol levels during early morning sleep in humans, reconsolidation processes change in a way that leads to the strengthening of episodic memory traces.SIGNIFICANCE STATEMENT How can we change formed memories? Modulation of established memories has been long debated in cognitive neuroscience and remains a crucial question to address for basic and clinical research. Stress-hormone cortisol and sleep are strong candidates for changing consolidated memories. In this double-blind, placebo-controlled, within-subject pharmacological study, we investigate the role of cortisol on the modulation of reconsolidation of episodic memories in humans. Blocking cortisol synthesis (3 g metyrapone) during early morning sleep boosts memory for a reactivated but not for a non-reactivated story. This finding contributes to our understanding of the modulatory role of cortisol and its circadian variability on reconsolidation, and moreover can critically inform clinical interventions for the case of memory dysfunctions, and trauma and stress-related disorders.

Clinical stage molecule PT150 is a modulator of glucocorticoid and androgen receptors with antiviral activity against SARS-CoV-2.

PT150 is a clinical-stage molecule, taken orally, with a strong safety profile having completed Phase 1 and Phase 2 clinical trials for its original use as an antidepressant. It has an active IND for COVID-19. Antiviral activities have been found for PT150 and other members of its class in a variety of virus families; thus, it was now tested against SARS-CoV-2 in human bronchial epithelial lining cells and showed effective 90% inhibitory antiviral concentration (EC90) of 5.55 µM. PT150 is a member of an extended platform of novel glucocorticoid receptor (GR) and androgen receptor (AR) modulating molecules. In vivo, their predominant net effect is one of systemic glucocorticoid antagonism, but they also show direct downregulation of AR and minor GR agonism at the cellular level. We hypothesize that anti-SARS-CoV-2 activity depends in part on this AR downregulation through diminished TMPRSS2 expression and modulation of ACE2 activity. Given that hypercortisolemia is now suggested to be a significant co-factor for COVID-19 progression, we also postulate an additive role for its potent immunomodulatory effects through systemic antagonism of cortisol.

Efficacy and safety of osilodrostat in patients with Cushing's disease (LINC 3): a multicentre phase III study with a double-blind, randomised withdrawal phase.

BACKGROUND: Cushing's disease is a rare endocrine disorder characterised by cortisol overproduction with severe complications. Therapies for cortisol reduction are often necessary. Here we report the outcomes from the pivotal phase III study of osilodrostat (a potent oral inhibitor of cytochrome P450 11B1, mitochondrial [11ß-hydroxylase]; Novartis Pharma AG, Basel, Switzerland) in patients with Cushing's disease. METHODS: LINC 3 was a prospective, multicentre, open-label, phase III study with a double-blind randomised withdrawal period, that comprised four periods. Patients aged 18-75 years, with confirmed persistent or recurrent Cushing's disease (defined as mean 24-h urinary free cortisol [UFC] concentration >1·5 times the upper limit of normal [ULN] and morning plasma adrenocorticotropic hormone above the lower limit of normal) who had previously had pituitary surgery or irradiation, or were newly diagnosed and who refused surgery or were not surgical candidates, were recruited from 66 hospital sites and private clinical practices in 19 countries. In period 1, open-label osilodrostat was initiated in all participants and adjusted every 2 weeks (1-30 mg twice daily; film-coated tablets for oral administration) on the basis of mean 24-h UFC concentration and safety until week 12. In period 2, weeks 13-24, osilodrostat was continued at the therapeutic dose determined during period 1. In period 3, beginning at week 26, participants who had a mean 24-h UFC concentration of less than or equal to the ULN at week 24, without up-titration after week 12, were randomly assigned (1:1), via an interactive-response technology, stratified by osilodrostat dose at week 24 and history of pituitary irradiation, to continue osilodrostat or switch to placebo for 8 weeks. Participants and investigators were masked to treatment assignment. Ineligible participants continued open-label osilodrostat. In period 4, weeks 35-48, all participants were given open-label osilodrostat until core-study end. The primary objective was to compare the efficacy of osilodrostat versus placebo at the end of period 3. The primary endpoint was the proportion of participants who had been randomly assigned to treatment or placebo with a complete response (ie, mean 24-h UFC concentration of ≤ULN) at the end of the randomised withdrawal period (week 34), without up-titration during this period. The key secondary endpoint was the proportion of participants with a complete response at the end of the single-arm, open-label period (ie, period 2, week 24) without up-titration during weeks 13-24. Analysis was by intention-to-treat for all patients who received at least one dose of osilodrostat (full analysis set; key secondary endpoint) or randomised treatment (randomised analysis set; primary endpoint) and safety was assessed in all enrolled patients who received at least one dose of osilodrostat and had at least one post-baseline safety assessment. LINC 3 is registered with ClinicalTrials.gov, NCT02180217, and is now complete. FINDINGS: Between Nov 12, 2014, and March 22, 2017, 202 patients were screened and 137 were enrolled. The median age was 40·0 years (31·0-49·0) and 106 (77%) participants were female. 72 (53%) participants were eligible for randomisation during the withdrawal phase, of whom 36 were assigned to continue osilodrostat and 35 were assigned to placebo; one patient was not randomly assigned due to investigator decision and continued open-label osilodrostat. More patients maintained a complete response with osilodrostat versus with placebo at week 34 (31 [86%] vs ten [29%]; odds ratio 13·7 [95% CI 3·7-53·4]; p<0·0001). At week 24, 72 (53%; 95% CI 43·9-61·1) of 137 patients maintained a complete response without up-titration after week 12. Most common adverse events (ie, occurred in >25% of participants) were nausea (57 [42%]), headache (46 [34%]), fatigue (39 [28%]), and adrenal insufficiency (38 [28%]). Hypocortisolism occurred in 70 (51%) patients and adverse events related to adrenal hormone precursors occurred in 58 (42%) patients. One patient died, unrelated to study drug, after the core study phase. INTERPRETATION: Twice-daily osilodrostat rapidly reduced mean 24-h UFC and sustained this reduction alongside improvements in clinical signs of hypercortisolism; it was also generally well tolerated. Osilodrostat is an effective new treatment option that is approved in Europe for the treatment of endogenous Cushing's syndrome and in the USA for Cushing's disease. FUNDING: Novartis Pharma AG.

Experimental manipulation of perceived predation risk and cortisol generates contrasting trait trajectories in plastic crucian carp.

Most animals constitute potential prey and must respond appropriately to predator-mediated stress in order to survive. Numerous prey also adaptively tailor their response to the prevailing level of risk and stress imposed by their natural enemies, i.e. they adopt an inducible defence strategy. Predator exposure may activate the stress axis, and drive the expression of anti-predator traits that facilitate survival in a high-risk environment (the predation-stress hypothesis). Here, we quantified two key morphological anti-predator traits, body morphology and coloration, in crucian carp reared in the presence or absence of a predator (pike) in addition to experimental manipulation of physiological stress via implants containing either cortisol or a cortisol inhibitor. We found that predator-exposed fish expressed a deeper-bodied phenotype and darker body coloration as compared with non-exposed individuals. Skin analyses revealed that an increase in the amount of melanophores caused the dramatic colour change in predator-exposed fish. Increased melanization is costly, and the darker body coloration may act as an inducible defence against predation, via a conspicuous signal of the morphological defence or by crypsis towards dark environments and a nocturnal lifestyle. By contrast, the phenotype of individuals carrying cortisol implants did not mirror the phenotype of predator-exposed fish but instead exhibited opposite trajectories of trait change: a shallow-bodied morphology with a lighter body coloration as compared with sham-treated fish. The cortisol inhibitor did not influence the phenotype of fish i.e. neither body depth nor body coloration differed between this group and predator-exposed fish with a sham implant. However, our results illuminate a potential link between stress physiology and morphological defence expression.

Demencia rápidamente progresiva como forma de presentación del síndrome de Cushing / Rapidly progressing dementia as a form of presentation of Cushing síndrome

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Radiotherapy as a tool for the treatment of Cushing's disease.

Treatment of Cushing's disease (CD) is one of the most challenging tasks in endocrinology. The first-line treatment, transsphenoidal pituitary surgery, is associated with a high failure rate and a high prevalence of recurrence. Re-operation is associated with an even higher rate of a failure and recurrence. There are three main second-line treatments for CD - pituitary radiation therapy (RT), bilateral adrenalectomy and chronic cortisol-lowering medical treatment. All these treatments have their limitations. While bilateral adrenalectomy provides permanent cure of the hypercortisolism in all patients, the unavoidable chronic adrenal insufficiency and the risk of development of Nelson syndrome are of concern. Chronic cortisol-lowering medical treatment is not efficient in all patients and side effects are often a limiting factor. RT is efficient for approximately two-thirds of all patients with CD. However, the high prevalence of pituitary insufficiency is of concern as well as potential optic nerve damage, development of cerebrovascular disease and secondary brain tumours. Thus, when it comes to decide appropriate treatment for patients with CD, who have either failed to achieve remission with pituitary surgery, or patients with recurrence, the pros and cons of all second-line treatment options must be considered.

MANAGEMENT OF ENDOCRINE DISEASE: Management of Cushing's syndrome during pregnancy: solved and unsolved questions.

With fewer than 200 reported cases, Cushing's syndrome (CS) in pregnancy remains a diagnostic and therapeutic challenge. In normal pregnancies, misleading signs may be observed such as striae or hypokalemia, while plasma cortisol and urinary free cortisol may rise up to 2- to 3-fold. While the dexamethasone suppression test is difficult to use, reference values for salivary cortisol appear valid. Apart from gestational hypertension, differential diagnosis includes pheochromocytoma and primary aldosteronism. The predominant cause is adrenal adenoma (sometimes without decreased ACTH), rather than Cushing's disease. There are considerable imaging pitfalls in Cushing's disease. Aberrant receptors may, in rare cases, lead to increased cortisol production during pregnancy in response to HCG, LHRH, glucagon, vasopressin or after a meal. Adrenocortical carcinoma (ACC) is rare and has poor prognosis. Active CS during pregnancy is associated with a high rate of maternal complications: hypertension or preeclampsia, diabetes, fractures; more rarely, cardiac failure, psychiatric disorders, infection and maternal death. Increased fetal morbidity includes prematurity, intrauterine growth retardation and less prevalently stillbirth, spontaneous abortion, intrauterine death and hypoadrenalism. Therapy is also challenging. Milder cases can be managed conservatively by controlling comorbidities. Pituitary or adrenal surgery should ideally be performed during the second trimester and patients should then be treated for adrenal insufficiency. Experience with anticortisolic drugs is limited. Metyrapone was found to allow control of hypercortisolism, with a risk of worsening hypertension. Cabergoline may be an alternative option. The use of other drugs is not advised because of potential teratogenicity and/or lack of information. Non-hormonal (mechanical) contraception is recommended until sustained biological remission is obtained.

A Single-Step "Breeding" Generated a Diagnostic Anti-cortisol Antibody Fragment with Over 30-Fold Enhanced Affinity.

Cortisol levels in bodily fluids represent a useful index for pituitary-adrenal function, and thus practical anti-cortisol antibodies are required. We have studied "antibody-breeding" approaches, which involve in vitro evolution of antibodies to improve their antigen-binding performances. Here, we produced an antibody fragment to measure serum cortisol levels with over 30-fold enhanced affinity after single mutagenesis and selection steps. A mouse anti-cortisol antibody, Ab-CS#3, with insufficient affinity for practical use, was chosen as the prototype antibody. A "wild-type" single-chain Fv fragment (wt-scFv; Ka, 3.4×108 M-1) was prepared by bacterial expression of a fusion gene combining the VH and VL genes for this antibody. Then, random point mutations were generated separately in VH or VL by error-prone PCR, and the resulting products were used to assemble scFv genes, which were displayed on filamentous phages. Repeated panning of the phage library identified a mutant scFv (scFv#m1-L10) with an over 30-fold enhanced affinity (Ka 1.2×1010 M-1). Three amino acid substitutions (Cys49Ser, Leu54Pro, and Ser63Gly) were observed in its VL sequence. In a competitive enzyme-linked immunosorbent assay (ELISA), the mutant scFv generated dose-response curves with measuring range ca. 0.03-0.6 ng/assay cortisol, midpoint of which (0.15 ng/assay) was 7.3-fold lower than that of wt-scFv. Although cortisone, 11-deoxycortisol, and prednisolone showed considerable cross-reactivity, the mutant scFv should enable sensitive routine cortisol assays, except for measurement after metyrapone or high-dose of prednisolone administrations. Actually, cortisol levels of control sera obtained with the scFv-based ELISA were in the reference range.

Urine protein electrophoresis study in dogs with pituitary dependent hyperadrenocorticism during therapy with trilostane / Avaliação da proteína urinária por eletroforese em cães com hiperadrenocorticismo hipófise dependente durante a terapia com trilostano

Hyperadrenocorticism is one of the most common endocrine disorders in dogs. Regarding to the kidneys, chronic hypercortisolemia can cause damage to the glomerulus, and evolve into chronic kidney disease. This study evaluated nine normotensive dogs with pituitary dependent hyperadrenocorticism, before and after therapy with trilostane, during the follow-up period of six months, in order to investigate the development of pathological proteinuria by quantitative (urinary protein-to-creatinine ratio) and qualitative (urinary protein electrophoresis) methods, and also to monitor its intensity over the course of the disease and therapy. The main renal lesion detected in dogs with hyperadrenocorticism was in the tubular segment, evidenced by the prevalence of urinary protein bands of lower molecular weight, indicating the lack absorption of these proteins in the proximal segment of the nephron. Low molecular weight proteins persisted throughout the follow-up. Regarding the future of routine veterinary medical clinic in the care of patients with hyperadrenocorticism, the assessments of proteinuria determinations by the urinary protein-to-creatinin ratio and urinary protein electrophoresis, according to the results obtained in this study, can add more information about the renal damage in these animals, and contribute to the prognosis.(AU)

Hiperadrenocorticismo (HAC) é uma das doenças endócrinas mais comuns em cães. A hipercortisolemia crônica pode causar danos glomerulares, pelo aumento da taxa de filtração glomerular, podendo levar ao desenvolvimento de doença renal crônica. Este estudo avaliou nove cães normotensos com hiperadrenocorticismo hipófise-dependente, antes e após a terapia com trilostano, durante o período de acompanhamento de seis meses, a fim de investigar o desenvolvimento de proteinúria patológica por métodos quantitativo (relação proteína e creatinina urinária) e qualitativos (eletroforese de proteínas urinárias) e também para monitorar a sua intensidade ao longo do curso da doença e terapia. A principal lesão renal detectada em cães com HAC foi no segmento tubular, evidenciada pela prevalência de bandas de proteínas urinárias de peso molecular mais baixo, indicando a falta de absorção destas proteínas no segmento proximal do néfron. A proteinúria de baixo peso molecular persistiu durante todo o acompanhamento. Em relação ao futuro da rotina clínica médica veterinária no tratamento de cães com hiperadrenocorticismo, as avaliações de proteinúria pela relação proteína e creatinina urinária e eletroforese de proteínas urinárias, de acordo com os resultados obtidos neste estudo, podem adicionar mais informações sobre a lesão renal nestes animais e contribuir para o prognóstico.(AU)

Optimization of left adrenal vein sampling in primary aldosteronism: Coping with asymmetrical cortisol secretion.

We evaluated the influence of catheter sampling position and size on left adrenal venous sampling (AVS) in patients with primary aldosteronism (PA) and analyzed their relationship to cortisol secretion. This retrospective study included 111 patients with a diagnosis of primary aldosteronism who underwent tetracosactide-stimulated AVS. Left AVS was obtained from two catheter positions - the central adrenal vein (CAV) and the common trunk. For common trunk sampling, 5-French catheters were used in 51 patients, and microcatheters were used in 60 patients. Autonomous cortisol secretion was evaluated with a low-dose dexamethasone suppression test in 87 patients. The adrenal/inferior vena cava cortisol concentration ratio [selectivity index (SI)] was significantly lower in samples from the left common trunk than those of the left CAV and right adrenal veins, but this difference was reduced when a microcatheter was used for common trunk sampling. Sample dilution in the common trunk of the left adrenal vein can be decreased by limiting sampling speed with the use of a microcatheter. Meanwhile, there was no significant difference in SI between the left CAV and right adrenal veins. Laterality, determined according to aldosterone/cortisol ratio (A/C ratio) based criteria, showed good reproducibility regardless of sampling position, unlike the absolute aldosterone value based criteria. However, in 11 cases with autonomous cortisol co-secretion, the cortisol hypersecreting side tended to be underestimated when using A/C ratio based criteria. Left CAV sampling enables symmetrical sampling, and may be essential when using absolute aldosterone value based criteria in cases where symmetrical cortisol secretion is uncertain.

Relationship between glucocorticoids and prolactin during mammary gland stimulation in dairy cows.

The objectives of this study were to determine the role of glucocorticoids in the regulation of prolactin (PRL) release induced by mammary gland stimulation and to investigate whether the milk depression induced by glucocorticoids in dairy cows is due to a decrease in PRL release. In experiment 1, 8 dairy cows were used in a 4 × 4 Latin square design. Four hours after the morning milking, the cows received 1 of the following treatments: (1) a 5-min manual stimulation of the mammary gland; (2) an i.v. injection of 1 mg of dexamethasone; (3) 2 infusions of 2.5 g of metyrapone (an inhibitor of cortisol biosynthesis) in the omasum 4 and 2 h before a 5-min stimulation of the mammary gland; or (4) no treatment. Sixty minutes later, the mammary gland of each cow was stimulated for 5 min. Blood samples were collected from 20 min before to 120 min after the start of the treatment. When the mammary gland was stimulated twice in 60 min, less PRL and cortisol were released during the second stimulation. Metyrapone did not affect PRL or cortisol release. Dexamethasone decreased serum cortisol concentration but did not affect PRL concentration. In experiment 2, 16 cows were used in a crossover experimental design consisting of 2 experimental weeks separated by 1 resting week. During the first week, cows were treated as follows: (1) 4 cows were injected with 0.5 g of domperidone (a PRL secretagogue) in canola oil on d 1 and 2 and 20 mg of dexamethasone on d 1; (2) 4 cows were injected with 0.5 g of domperidone on d 1 and 2; (3) 4 cows were injected with canola oil on d 1 and 2 and with 20 mg of dexamethasone on d 1; and (4) 4 cows were injected with canola oil on d 1 and 2. During the second experimental week, the same 4 treatments were repeated, except the cows that did not receive dexamethasone in the first week received it on d 1 of the second week, and cows that did receive it in the first week did not receive it in the second week. On d 1 and 2 of each week, blood samples were collected during morning milking for PRL determination. Dexamethasone reduced milk production and decreased both basal and milking-induced PRL release. It also increased milk fat and protein percentages and decreased milk lactose content. Domperidone increased basal PRL levels in serum and milk but did not affect milk yield. Although we cannot rule out the possibility that inhibition of PRL secretion or reduction of mammary gland PRL responsiveness play a role in the inhibition of milk production by glucocorticoids, the fact that enhancement of PRL secretion by domperidone could not prevent the depression of milk yield suggests that other mechanisms are involved.

Adrenal Suppression With Chronic Topical Corticosteroid Use in Psoriasis Patients.

BACKGROUND: Topical corticosteroids (TCS) are typically used for extended periods of time for chronic skin conditions, including psoriasis. Chronic TCS use may result in side effects similar to those of systemic corticosteroids. Patients may have subclinical adrenal suppression and be unaware of their risk in the case of serious trauma.
OBJECTIVE: The objective of this study was to investigate the real world effects of chronic TCS use and its effects on adrenal suppression in a chronic disease such as psoriasis.
MATERIALS: This retrospective study utilized data from screening visits of a psoriasis clinical trial in which subjects had been on chronic TCS.
RESULTS: In this study, subjects with moderate to severe psoriasis affecting 16-20% of total body surface area (BSA) and using high-potency TCS at screening had a lower post-cosyntropin cortisol level (18.83 mcg/dL) compared to those with moderate psoriasis involving 10-15% of total BSA and using lower potency TCS at screening (23.22 mcg/dL; P=0.03). Both subject groups had lower post-cosyntropin cortisol levels compared to normal, healthy adults (P<0.001 for both).
CONCLUSION: This suggests that real world chronic use of high potency TCS over a larger BSA may result in silent adrenal suppression.

J Drugs Dermatol. 2016;15(8):945-948.

Development of CYB5-fusion monitoring system for efficient periplasmic expression of multimeric proteins in Escherichia coli.

Despite all advances of heterologous expression of recombinant proteins in Escherichia coli, expression of multidomain disulphide-rich proteins faces some problems due to the absence of the possibility to monitor the process in real-time. Here we provide a CYB5-fusion system - cytochrome b5 fusion system for periplasmic expression of multimeric proteins with the possibility of process monitoring. We validated this system by Fab and scFv antibody fragments expression in order to improve antibody-derived molecules characterization and to simplify their usage. The combination of redox dependent absorbance spectrum of red-colored cytochrome b5 with its high value molar extinction coefficient allows us to monitor antibody fusion proteins localization, redox state and quantify them in reliable way in turbid solutions. Moreover, it was revealed that due to outstanding stability and solubility, cytochrome b5 significantly enhances expression level of Fab/scFv antibody fragments in Escherichia coli periplasm.

Chronic Supplementation of Curcumin Enhances the Efficacy of Antidepressants in Major Depressive Disorder: A Randomized, Double-Blind, Placebo-Controlled Pilot Study.

Major depressive disorder is a devastating mental illness leading to a lifetime prevalence of higher than 16% on individuals. The treatment delay and inevitable adverse effects are major limitations of current depression interventions. Emerging evidence indicates that curcumin produced significant antidepressant properties in depression in both rodents and humans without adverse effects. Therefore, it is necessary to further clarify the antidepressant actions of curcumin and the underlying mechanism in depressed patients. A total of 108 male adults aged between 31 and 59 years were systematically recruited in Tianjin Anding Hospital. Subjects were administered the Chinese version of 17-item Hamilton Depression Rating Scale and Montgomery-Asberg Depression Rating Scale that measures different scores of depressive symptoms. The subjects were asked to take 2 capsules containing either 1000 mg of curcumin or placebo soybean powder daily for 6 weeks on the basis of their current antidepressant medications. The plasma levels of interleukin 1ß, tumor necrosis factor α, brain-derived neurotrophic factor, and salivary cortisol were measured by enzyme-linked immunosorbent assay before and after curcumin or placebo treatment during the 6-week procedure. Chronic supplementation with curcumin produced significant antidepressant behavioral response in depressed patients by reduction of 17-item Hamilton Depression Rating Scale and Montgomery-Asberg Depression Rating Scale scores. Furthermore, curcumin decreases inflammatory cytokines interleukin 1ß and tumor necrosis factor α level, increases plasma brain-derived neurotrophic factor levels, and decreases salivary cortisol concentrations compared with placebo group. These findings indicate the potential benefits of further implications of supplementary administration of curcumin to reverse the development of depression and enhance the outcome of antidepressants treatment in major depressive disorder.

Vitamin C Prevents Sleep Deprivation-induced Elevation in Cortisol and Lipid Peroxidation in the Rat Plasma.

Sleep deprivation (SD) is biological stressor that alters metabolic parameters, induced oxidative stress and lipid peroxidation. Previous studies have shown that antioxidants substances such as melatonin, tryptophan, vitamin E and vitamin C improved stress tolerance in laboratory animals. In this study, we examined the potential protective effects of administration of vitamin C on acute and chronic sleep deprivation-induced metabolic derangement. In addition, possible processes involved in vitamin C effects on acute and chronic sleep deprivation-induced metabolic derangement were determined. Thirty-five rats (120-250g) were used. The rats were divided into 7 groups of 5 rats each as Control (CTRL), Acute sleep deprived untreated with vitamin C (AC), Acute sleep deprived treated with vitamin C (AWC), Chronic sleep deprived untreated with vitamin C (CC), Chronic sleep deprived treated with vitamin C (CWC), Chronic sleep deprived + Recovery untreated with vitamin C (RC), and Chronic sleep deprived + Recovery treated with vitamin C (RWC). The SD was carried out for 20h for 1 day on the acute groups, and for 20h/day for 5 days on the chronic group, using the Multiple Modified Platforms (MMP) after oral administration of 300mg/kg of vitamin C to all vitamin C-treated groups. The recovery groups were further observed for five days after SD. The control group were treated with vitamin C and without stress in their home cages. At the end of the experiment, the animals were sacrificed and blood was collected for estimation of plasma glucose, insulin, cortisol and malondialdehyde (MDA). The results showed that acute and chronic SDs significantly  increased MDA and cortisol levels, while significantly reduced the levels of insulin. Treatment with vitamin C reversed the changes in the MDA, cortisol and plasma insulin levels. Additionally, allowing the rats to recover for 5 days after sleep deprivation corrected the observed changes. Plasma glucose was significantly reduced in all the sleep deprived groups compared to the control. In conclusion, sleep deprivation induced metabolic, hormonal and lipid peroxidation derangement, and treatment with vitamin C prevented these impairments. Thus, the effects of vitamin C could improve stress tolerance in rats.

High incidence of adrenal suppression in children with Kawasaki disease treated with intravenous immunoglobulin plus prednisolone.

Combination treatment with intravenous immunoglobulin (IVIG) plus prednisolone, newly designed for children with severe Kawasaki disease (KD), reduces coronary artery abnormalities significantly. As prednisolone is administered for approximately 20 days in this regimen, we examined whether adrenal function of the treated patients is suppressed. A prospective study was performed at one medical institution in 21 children with KD (age range 0.3-10.4 years, median 3.1 years) who were treated with the regimen between February and June, 2012. We assessed cortisol and ACTH values before the initiation and after the cessation of prednisolone administration as well as peak cortisol and ACTH values at corticotropin-releasing hormone (CRH) stimulation tests, which were repeated 0, 2, and 6 months after the treatment. Morning cortisol and ACTH values after the cessation of prednisolone treatment were suppressed. Peak cortisol values at the first CRH stimulation test ranged from 5.1 to 25.4 µg/dL and were less than 20 µg/dL in 17 of 21 patients, but were restored to more than 14.6 µg/dL in all patients by 6 months after the prednisolone treatment. A significant positive correlation was observed between cortisol values at 09:00 h after the prednisolone treatment and peak cortisol values at the following CRH stimulation test (r = 0.727, p < 0.001). We conclude that adrenal suppression can occur in a high proportion of children with KD treated with IVIG plus prednisolone, despite rather short duration and relatively small amounts of administered glucocorticoids.

Plasma concentration-dependent suppression of endogenous hydrocortisone in the horse after intramuscular administration of dexamethasone-21-isonicotinate.

Detection times and screening limits (SL) are methods used to ensure that the performance of horses in equestrian sports is not altered by drugs. Drug concentration-response relationship and knowledge of concentration-time profiles in both plasma and urine are required. In this study, dexamethasone plasma and urine concentration-time profiles were investigated. Endogenous hydrocortisone plasma concentrations and their relationship to dexamethasone plasma concentrations were also explored. A single dose of dexamethasone-21-isonicotinate suspension (0.03 mg/kg) was administered intramuscularly to six horses. Plasma was analysed for dexamethasone and hydrocortisone and urine for dexamethasone, using UPLC-MS/MS. Dexamethasone was quantifiable in plasma for 8.3 ± 2.9 days (LLOQ: 0.025 µg/L) and in urine for 9.8 ± 3.1 days (LLOQ: 0.15 µg/L). Maximum observed dexamethasone concentration in plasma was 0.61 ± 0.12 µg/L and in urine 4.2 ± 0.9 µg/L. Terminal plasma half-life was 38.7 ± 19 h. Hydrocortisone was significantly suppressed for 140 h. The plasma half-life of hydrocortisone was 2.7 ± 1.3 h. Dexamethasone potency, efficacy and sigmoidicity factor for hydrocortisone suppression were 0.06 ± 0.04 µg/L, 0.95 ± 0.04 and 6.2 ± 4.6, respectively. Hydrocortisone suppression relates to the plasma concentration of dexamethasone. Thus, determination of irrelevant plasma concentrations and SL is possible. Future research will determine whether hydrocortisone suppression can be used as a biomarker of the clinical effect of dexamethasone.

Agrichemicals chronically inhibit the cortisol response to stress in fish.

We studied the stress response of Rhamdia quelen fingerlings at 45, 90, 135 and 180 d following acute exposure to agrichemicals. Herein, we report the novel observation that acute exposure of fingerling-aged fish to a methyl parathion-based insecticide (MPBI) and to a tebuconazole-based fungicide (TBF) induced chronic inhibition of the stress response. In contrast, fish exposed to an atrazine-simazine-based herbicide (ASBH) recovered the stress response on day 45, and fish exposed to a glyphosate-based herbicide (GBH) did not present stress response inhibition. Additionally, fish exposed to MPBI, GBH and ASBH showed lower survival rates and attained lower final weights. In the case of TBF, the presence of the stressful stimulus more strongly influenced the changes in the performance parameters than did the agrichemical exposure itself. An impairment of the cortisol response may seriously hamper the adaptive response and the ability to promote the necessary metabolic and ionic adjustments to respond to environmental stress.