Reduced glucocorticoid receptor protein expression in children with critical illness

Theory and Practice of Glucocorticoids in COVID-19: Getting to the Heart of the Matter-A Critical Review and Viewpoints

Prolonged, low-dose glucocorticoids (GCs) have shown the highest efficacy among pharmacological and non-pharmacological treatments for COVID-19. Despite the World Health Organization's recommendation against their use at the beginning of the pandemic, GCs at a dose equivalent to dexamethasone 6 mg/day for 10 days are now indicated in all COVID-19 cases who require respiratory support. However, the efficacy of the intervention depends on the timing of initiation, the dose, and other individual factors. Indeed, patients treated with similar GC protocols often experience different outcomes, which do not always correlate with the presence of comorbidities or with the severity of respiratory involvement at baseline. This prompted us to critically review the literature on the rationale, pharmacological principles, and clinical evidence that should guide GC treatment. Based on these data, the best treatment protocol probably involves an initial bolus dose to saturate the glucocorticoid receptors, followed by a continuous infusion to maintain constant plasma levels, and eventually a slow tapering to interruption. Methylprednisolone has shown the highest efficacy among different GC molecules, most likely thanks to its higher ability to penetrate the lung. Decreased tissue sensitivity to glucocorticoids is thought to be the main mechanism accounting for the lower response to the treatment in some individuals. We do not have a readily available test to identify GC resistance; therefore, to address inter-individual variability, future research should aim at investigating clinical, physiological, and laboratory markers to guide a personalized GC treatment approach.

Changes in Cortisol Secretion and Corticosteroid Receptors in COVID-19 and Non COVID-19 Critically Ill Patients with Sepsis/Septic Shock and Scope for Treatment

Sepsis is associated with dysregulated cortisol secretion, leading to abnormal levels of cortisol in the blood. In the early stages of the condition, cortisol levels are typically elevated due to increased secretion from the adrenal glands. However, as the disease progresses, cortisol levels may decline due to impaired adrenal function, leading to relative adrenal insufficiency. The latter is thought to be caused by a combination of factors, including impaired adrenal function, decreased production of corticotropin-releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) by the hypothalamus and pituitary gland, and increased breakdown of cortisol. The dysregulation of cortisol secretion in sepsis is thought to contribute to the pathophysiology of the disease by impairing the body's ability to mount an appropriate inflammatory response. Given the dysregulation of cortisol secretion and corticosteroid receptors in sepsis, there has been considerable interest in the use of steroids as a treatment. However, clinical trials have yielded mixed results and corticosteroid use in sepsis remains controversial. In this review, we will discuss the changes in cortisol secretion and corticosteroid receptors in critically ill patients with sepsis/septic shock. We will also make special note of COVID-19 patients, who presented a recent challenge for ICU management, and explore the scope for corticosteroid administration in both COVID-19 and non-COVID-19 septic patients.

Glucocorticoid receptor expression in patients with cardiac arrest in the early period after the return of spontaneous circulation: a prospective observational single-centre study

OBJECTIVES

Rapid changes in glucocorticoid (GC) levels and adrenal insufficiency are related to the development of post-cardiac arrest (CA) syndrome. However, GC receptor (GR) expression changes have not been studied. Hence, this study aimed to investigate the association of early changes in GR expression and prognosis and immune response in patients who experienced CA.

DESIGN

Prospective observational study.

SETTING

Emergency department.

PARTICIPANTS

Patients (85) in the early period of return of spontaneous circulation (ROSC) after CA were admitted between October 2018 and October 2019. After a physical examination, age-matched and sex-matched healthy individuals (40) were recruited for the control group.

PRIMARY AND SECONDARY OUTCOME MEASURES

GR expression and cell counts of circulatory T and B lymphocytes, natural killer cells and regulatory T (Treg) cells were assessed. Plasma total cortisol and adrenocorticotrophic hormone (ACTH) levels were also tested.

RESULTS

All cell counts were lower, and plasma total cortisol levels were higher (p<0.001) in patients who experienced CA than in the healthy control group. GR expression in Treg cells and CD3+CD4+ T lymphocytes were not significantly different, but the mean fluorescence intensity and GR expression in other cells were lower in patients who experienced CA (p<0.05) than in the healthy control group. ACTH levels were not different. There were no significant differences between survivors and non-survivors.

CONCLUSIONS

This study revealed that GR expression and cell counts rapidly decreased, whereas plasma total cortisol levels increased in the early period after ROSC among patients who experienced CA. Our findings provide important information about GR level and function, and immunosuppressive status in these patients. Assessing GR expression in patients who experienced CA may help screening for those who are more sensitive to GC therapy.

Pituitary-Adrenal Responses and Glucocorticoid Receptor Expression in Critically Ill Patients with COVID-19

The hypothalamus-pituitary-adrenal (HPA) axis was described as the principal component of the stress response 85 years ago, along with the acute-phase reaction, and the defense response at the tissue level. The orchestration of these processes is essential since systemic inflammation is a double-edged sword; whereas inflammation that is timely and of appropriate magnitude is beneficial, exuberant systemic inflammation incites tissue damage with potentially devastating consequences. Apart from its beneficial cardiovascular and metabolic effects, cortisol exerts a significant immunoregulatory role, a major attribute being that it restrains the excessive inflammatory reaction, thereby preventing unwanted tissue damage. In this review, we will discuss the role of the HPA axis in the normal stress response and in critical illness, especially in critically ill patients with coronavirus disease 2019 (COVID-19). Finally, a chapter will be dedicated to the findings from clinical studies in critical illness and COVID-19 on the expression of the mediator of glucocorticoid actions, the glucocorticoid receptor (GCR).

Hypoglycemia and mortality in sepsis patients: A systematic review and meta-analysis

BACKGROUND

Hypoglycemia frequently occurs in patients with sepsis. The status of prognosis of sepsis patients varies with the cause of hypoglycemia.

OBJECTIVE

A meta-analysis was performed to obtain a reliable basis for assessing the severity of disease in sepsis patients.

METHODS

A search of electronic databases was performed. The random-effects model was employed to calculate the overall odds ratio (OR) and 95% CI.

RESULTS

Five cohort studies were included. Decreased blood glucose level was associated with an increased risk of death [OR:1.68; 95% CI (1.12-2.53)]. Incidents of mortality were analyzed based on the causative factor of hypoglycemia. Patients with spontaneous hypoglycemia showed a significantly higher mortality rate than the control subjects[OR 1.65; 95% CI (1.20-2.28); p = 0.002].

CONCLUSION

In the early stages of sepsis, the occurrence of spontaneous hypoglycemia may be associated with the severity of the disease.

Leukocyte glucocorticoid receptor expression and related transcriptomic gene signatures during early sepsis

PURPOSE

The study aimed to understand the molecular mechanisms that might lead to differences in the glucocorticoid response during sepsis.

METHODS

Patients diagnosed with sepsis (n = 198) and 40 healthy controls were enrolled. Glucocorticoid receptor (GR) expression in circulating leukocytes and plasma levels of adrenocorticotropic hormone and cortisol on days 1 and 7 were measured in all participants. Expression profiling of 16 genes associated with GR expression in peripheral blood mononuclear cells (PBMCs) in 12 healthy controls and 26 patients with sepsis was performed by PCR.

RESULTS

Cortisol levels were higher in patients with sepsis than in healthy controls on day 1 after admission and recovered to normal levels by day 7. GR expression was gradually downregulated in leukocyte subsets. Non-survivors showed lower GR and higher cortisol levels than survivors. GRα expression was lower in patients with sepsis than in controls, whereas GRβ showed the opposite trend. MicroRNAs related to GR resistance and suppression were altered in PBMCs during sepsis.

CONCLUSION

Patients with sepsis showed upregulated plasma cortisol levels along with downregulated GR expression on various leukocyte subtypes, portending poor cortisol response and outcome. Changes in GR-regulatory miRNAs may be responsible for GR low expression.

New insight of adrenal responses in premature neonates versus full term neonates in critical care setting.. [DOI: 10.1101/2020.07.15.20154849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background

Adequate adrenocortical function is essential for survival of critically ill neonates. Although most of them display elevated plasma cortisol concentrations, which reflects activation of the hypothalamic pituitary adrenal axis (HPA), yet; adrenocortical insufficiency is seen in septic shock. Objectives: Evaluate the HPA response in critically ill neonates with shock.

Methods

this prospective observational Participant: a total of 60 neonates divided into 3 groups;(A) 30 critical ill neonates with septic shock on inotropic support, (B)15 patients with sepsis with no inotropic support and(C) control group(n=15). Intervention: a single diurnal ACTH reading and two readings for serum cortisol level (diurnal and nocturnal).

Results

Gram negative organism was more prevalent among the patients; 53%, 63% in groups A and B respectively. Group A showed Significant statistical hypotension before vasopressor drug administration (p<0.001) as compared to both groups. Group A showed Significant statistical improvement of blood pressure after vasopressor drug administration (p<0.001) as compared to both groups B, C. Serum cortisol was significantly higher in group A(57.21±24.31) and B (48.01±18.27), while it was lower in group C(19.57±16.05). A highly statistically significant rise of serum cortisol level(p=0.000) and ACTH(p=0.000) in group A when was compared to the other two groups.

Conclusion

This study introduced a new pattern of serum cortisol response in neonates ranging from very high cortisol level to a near normal values; highlighting a state of glucocorticoid resistance in neonates and relative adrenal insufficiency.

General Adaptation in Critical Illness: Glucocorticoid Receptor-alpha Master Regulator of Homeostatic Corrections

In critical illness, homeostatic corrections representing the culmination of hundreds of millions of years of evolution, are modulated by the activated glucocorticoid receptor alpha (GRα) and are associated with an enormous bioenergetic and metabolic cost. Appreciation of how homeostatic corrections work and how they evolved provides a conceptual framework to understand the complex pathobiology of critical illness. Emerging literature place the activated GRα at the center of all phases of disease development and resolution, including activation and re-enforcement of innate immunity, downregulation of pro-inflammatory transcription factors, and restoration of anatomy and function. By the time critically ill patients necessitate vital organ support for survival, they have reached near exhaustion or exhaustion of neuroendocrine homeostatic compensation, cell bio-energetic and adaptation functions, and reserves of vital micronutrients. We review how critical illness-related corticosteroid insufficiency, mitochondrial dysfunction/damage, and hypovitaminosis collectively interact to accelerate an anti-homeostatic active process of natural selection. Importantly, the allostatic overload imposed by these homeostatic corrections impacts negatively on both acute and long-term morbidity and mortality. Since the bioenergetic and metabolic reserves to support homeostatic corrections are time-limited, early interventions should be directed at increasing GRα and mitochondria number and function. Present understanding of the activated GC-GRα's role in immunomodulation and disease resolution should be taken into account when re-evaluating how to administer glucocorticoid treatment and co-interventions to improve cellular responsiveness. The activated GRα interdependence with functional mitochondria and three vitamin reserves (B1, C, and D) provides a rationale for co-interventions that include prolonged glucocorticoid treatment in association with rapid correction of hypovitaminosis.

Decreased glucocorticoid receptor expression during critical illness

INTRODUCTION

In critically ill patients, the hypothalamic-pituitary-adrenal axis is activated, resulting in increased serum cortisol concentrations. However, in some patients, especially those with sepsis, cortisol levels are relatively low for the degree of illness severity. Therefore, in the present project, we aim to characterize the time course of glucocorticoid receptor (GCR) alpha and beta expression in peripheral polymorphonuclear cells of critically ill septic or nonseptic patients using real-time PCR.

DESIGN

A prospective observational study conducted on 32 critically ill adults not receiving steroids, in a university-affiliated, multidisciplinary intensive care unit (ICU). Blood samples were collected for measurement of glucocorticoid receptor expression within 24-48 hours of admission to the ICU and at days 4, 8 and 13 after admission, reflecting the acute and chronic phase of the illness.

RESULTS

During ICU stay, patients expressed over time reduced levels of both GCR-α and GCR-β mRNA. More specifically, GCR-α mRNA expression was decreased fourfold 4 days after admission (P < 0.0001) and remained low up to 2 weeks after admission (P < 0.001). On the other hand, GCR-β mRNA levels remained stable shortly after admission, but approx. one week after admission, its levels decreased threefold (P < 0.01) and remained reduced up to 2 weeks after admission (P < 0.001).

DISCUSSION

Our results suggest that critically ill patients have highly variable expression of alpha and beta GCR, and moreover, the levels of both receptors decrease during ICU stay. Taken together, these might explain the differential responsiveness of patients to exogenous steroid administration or to endogenous cortisol secretion.

Elevated Baseline Cortisol Levels Are Predictive of Bad Outcomes in Critically Ill Children

OBJECTIVE

The definition of an adequate adrenal response in critically ill children continues to be controversial. We aimed to evaluate the cortisol levels at baseline and after adrenocorticotropin (ACTH) stimulation and determine their association to clinical outcome of critically ill children.

METHODS

All children who underwent an ACTH test in the pediatric intensive care unit (PICU) in a tertiary medical center between 2006 and 2013 were included in the study. Data on age, sex, diagnosis, vasoactive-inotropic score, length of pediatric intensive care unit stay, and mortality were obtained. Laboratory variables included hematologic and chemistry data, arterial lactate, and total plasma cortisol levels at baseline and after ACTH stimulation.

RESULTS

Ninety-nine patients (61 males; median [range] age, 2 [0-204] months) were enrolled. The mortality rate of children with a baseline cortisol level of 600 nmol/L or greater was 36% (12/33 patients) versus 18% (12/66 patients) for children with a baseline cortisol level of less than 600 nmol/L (odds ratio, 2.6 [95% confidence interval, 1-6.6]; P = 0.05). There was a positive correlation between baseline cortisol and lactate levels (r = 0.40, P < 0.0001), vasoactive-inotropic scores (r = 0.24, P = 0.02), and mortality (P = 0.05). There was no correlation between peak cortisol measured at the ACTH test or the delta increment of cortisol from baseline and mortality.

CONCLUSIONS

A high baseline cortisol level in critically ill children was associated with more severe illness, higher lactate level, and a higher mortality rate. Routine baseline cortisol assessment is recommended to identify patients at high mortality risk.

Characterization of the Glucocorticoid Receptor in Children Undergoing Cardiac Surgery

OBJECTIVES

Postoperative administration of corticosteroids is common practice for managing catecholamine refractory low cardiac output syndrome. Since corticosteroid activity is dependent on the glucocorticoid receptor, we sought to characterize glucocorticoid receptor levels in children undergoing cardiac surgery and examined the association between glucocorticoid receptor levels and cardiovascular dysfunction.

DESIGN

Prospective observational cohort study.

SETTING

Large, tertiary pediatric cardiac center.

SUBJECTS

Children undergoing corrective or palliative cardiac surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A prospective observational cohort study was conducted in 83 children with congenital heart disease. Total glucocorticoid receptor levels were measured in the peripheral WBCs using flow cytometry. In addition, blood samples were collected for total cortisol levels. The primary outcome studied was the time to being inotrope free. An increase in glucocorticoid receptor level from postoperative day 1 to postoperative day 3 was associated with a longer time to being inotrope free (hazard ratio, 0.49 [0.29-0.81]; p = 0.01) in the univariate analysis. This association remained significant after adjusting for age, weight, cardiopulmonary bypass time, cross clamp time, Risk Adjustment for Congenital Heart Surgery-1 score, and postoperative steroid use (hazard ratio, 0.53 [0.29-0.99]; p = 0.05). Postoperative day 3 glucocorticoid receptor level showed a trend to have longer time to being inotrope free (hazard ratio, 0.66 [0.42-1.02]; p = 0.0.06). The cortisol levels minimally increased during the study duration and did not correlate with glucocorticoid receptor levels.

CONCLUSIONS

Increasing glucocorticoid receptor levels in peripheral WBCs of children undergoing cardiac surgery are associated with a longer time to being inotrope free. Cortisol levels minimally increased during the study duration. These results suggest that exposure to high-dose perioperative corticosteroids may suppress the hypothalamic-pituitary-adrenal axis leading to increase in glucocorticoid receptor levels in response to a low cortisol environment. Further studies are required to better delineate the interplay between glucocorticoid receptor levels, cortisol levels, corticosteroid exposure, and postoperative inotropic requirements.

Random serum free cortisol and total cortisol measurements in pediatric septic shock

Background The aim of the study was to examine the relationship between serum total cortisol (TC) and free cortisol (FC) levels in children with septic shock and the relationship of these levels with baseline illness severity. Methods A sub-study of a randomized controlled trial (RCT) of hydrocortisone vs. placebo in pediatric septic shock conducted in seven academic pediatric intensive care units (PICUs) in Canada on children aged newborn to 17 years. Thirty children with septic shock had serum sent for TC and FC measurement within 6 h of meeting the study eligibility criteria. Results Baseline FC and TC levels were strongly correlated with baseline Pediatric Risk of Mortality (PRISM) score (R2=0.759, p<0.001; R2=0.717, p<0.001) and moderately correlated with admission Vasotropic Inotropic Score (VIS) (R2=0.489, p<0.001; R2=0.316, p<0.001). Serum TC levels were highly correlated with FC levels (R2=0.92, p<0.001) and showed strong agreement (R2=0.98, p<0.001 on a Bland-Altman plot). The ratio of FC to TC moderately correlated with TC levels (R2=0.46, p<0.001) but did not correlate with baseline albumin levels (R2=0.19, p=0.13). Conclusions Random TC and FC levels are strongly correlated, show strong agreement and are reflective of illness severity in children with septic shock. As such, isolated FC measurement does not appear to provide added information relative to TC in acutely ill children with septic shock.

The Hepatic Glucocorticoid Receptor Is Crucial for Cortisol Homeostasis and Sepsis Survival in Humans and Male Mice

Sepsis is hallmarked by hypercortisolemia, a stress response essential for survival. This elevation in plasma cortisol is partially brought about by suppressed hepatic cortisol breakdown. We demonstrate that a controlled downregulation of the hepatic glucocorticoid receptor (hepatic GR) is crucial. In a mouse model of fluid-resuscitated, antibiotic-treated abdominal sepsis and in human intensive care unit patients, sepsis reduced hepatic GR expression and signaling but increased (free) plasma cortisol/corticosterone, explained by suppressed cortisol/corticosterone-binding proteins and A-ring reductases. However, further experimental inhibition of hepatic GR with short hairpin RNA (shRNA) in septic mice increased mortality fivefold. Acutely, this further hepatic GR suppression prevented the rise in total corticosterone but further reduced binding proteins, resulting in elevated free corticosterone. After 3 days of shRNA-GR inhibition in sepsis, both total and free corticosterone levels were elevated, now explained by an additional reduction in A-ring reductase expression. Hepatic GR inhibition blunted the hyperglycemic stress response without causing hypoglycemia but also markedly increased circulating and hepatic inflammation markers and caused liver destruction, the severity of which explained increased mortality. In human sepsis, glucocorticoid treatment further suppressed hepatic GR expression, which could directly predispose to worse outcomes. In conclusion, sepsis partially suppressed hepatic GR expression, which appeared crucial to upregulate free cortisol/corticosterone availability. However, further sustained hepatic GR suppression evoked lethal excessive liver and systemic inflammation, independent of systemic cortisol/corticosterone availability.

American College of Critical Care Medicine Clinical Practice Parameters for Hemodynamic Support of Pediatric and Neonatal Septic Shock

OBJECTIVES

The American College of Critical Care Medicine provided 2002 and 2007 guidelines for hemodynamic support of newborn and pediatric septic shock. Provide the 2014 update of the 2007 American College of Critical Care Medicine "Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock."

DESIGN

Society of Critical Care Medicine members were identified from general solicitation at Society of Critical Care Medicine Educational and Scientific Symposia (2006-2014). The PubMed/Medline/Embase literature (2006-14) was searched by the Society of Critical Care Medicine librarian using the keywords: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation, and American College of Critical Care Medicine guidelines in the newborn and pediatric age groups.

MEASUREMENTS AND MAIN RESULTS

The 2002 and 2007 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and American Heart Association/Pediatric Advanced Life Support sanctioned recommendations. The review of new literature highlights two tertiary pediatric centers that implemented quality improvement initiatives to improve early septic shock recognition and first-hour compliance to these guidelines. Improved compliance reduced hospital mortality from 4% to 2%. Analysis of Global Sepsis Initiative data in resource rich developed and developing nations further showed improved hospital mortality with compliance to first-hour and stabilization guideline recommendations.

CONCLUSIONS

The major new recommendation in the 2014 update is consideration of institution-specific use of 1) a "recognition bundle" containing a trigger tool for rapid identification of patients with septic shock, 2) a "resuscitation and stabilization bundle" to help adherence to best practice principles, and 3) a "performance bundle" to identify and overcome perceived barriers to the pursuit of best practice principles.

Increased glucocorticoid receptor expression in sepsis is related to heat shock proteins, cytokines, and cortisol and is associated with increased mortality

Background

The purposes of this study are to examine if the human glucocorticoid receptor (hGR) isoform-α mRNA and hGR protein expressions are deficient in the acute phase of sepsis (S) compared to systemic inflammatory response syndrome (SIRS) and healthy subjects (H) and to evaluate if the hGRα and hGR alterations are associated with cortisol changes and if they are related to (1) extracellular and intracellular heat shock proteins (HSP) 72 and 90α; (2) ACTH, prolactin, and interleukins (ILs); and (3) outcome.

Methods

Patients consecutively admitted to a university hospital intensive care unit (ICU) with S (n = 48) or SIRS (n = 40) were enrolled in the study. Thirty-five H were also included. Total mRNA was isolated from peripheral blood samples and cDNA was prepared. RT-PCR was performed. Intracellular hGR and HSP expression in monocytes and/or neutrophils was evaluated using four-colour flow cytometry. Serum prolactin, ACTH, and cortisol concentrations were also measured. ELISA was used to evaluate serum ILs and extracellular (e) HSPs (eHSP72, eHSP90α).

Results

hGR protein was higher in S compared to H and SIRS; hGRα mRNA was higher in S compared to H (p < 0.05). In sepsis, hGR protein and eHSP72 were higher among non-survivors compared to survivors (p < 0.05). The hGR MFI and hGRα mRNA fold changes were significantly related to each other (r_s = 0.64, p < 0.001). Monocyte hGR protein expression was positively correlated with extracellular and intracellular HSPs, cortisol, and ILs and negatively to organ dysfunction (p < 0.05). HSPs, hGR, and cortisol were able to discriminate sepsis from SIRS (AUROC > 0.85, p < 0.05). In sepsis, monocyte-hGR protein and eHSP72 were strong predictors of mortality (AUROC > 0.95, p < 0.04).

Conclusions

Acute-phase sepsis is associated with increased hGR expression and cortisol concentrations, possibly implying no need for exogenous steroids. At this stage, hGR is able to predict sepsis and outcome and is related to stress-activated bio-molecules and organ dysfunction.

MECHANISMS IN ENDOCRINOLOGY: New concepts to further unravel adrenal insufficiency during critical illness

The concept of 'relative' adrenal insufficiency during critical illness remains a highly debated disease entity. Several studies have addressed how to diagnose or treat this condition but have often yielded conflicting results, which further fuelled the controversy. The main reason for the controversy is the fact that the pathophysiology is not completely understood. Recently, new insights in the pathophysiology of the hypothalamic-pituitary-adrenal axis response to critical illness were generated. It was revealed that high circulating levels of cortisol during critical illness are explained more by reduced cortisol breakdown than by elevated cortisol production. Cortisol production rate during critical illness is less than doubled during the day but lower than in healthy subjects during the night. High plasma cortisol concentrations due to reduced breakdown in turn reduce plasma ACTH concentrations via feedback inhibition, which with time may lead to an understimulation and hereby a dysfunction of the adrenal cortex. This could explain the high incidence of adrenal insufficiency in the prolonged phase of critical illness. These novel insights have created a new framework for the diagnosis and treatment of adrenal failure during critical illness that has redirected future research.

Glucocorticoid receptor expression and binding capacity in patients with burn injury

BACKGROUND

Burn injuries are associated with strong inflammation and risk of secondary sepsis which both may affect the function of the glucocorticoid receptor (GR). The aim of this study was to determine GR expression and binding capacity in leucocytes from patients admitted to a tertiary burn center.

METHODS

Blood was sampled from 13 patients on admission and days 7, 14 and 21, and once from 16 healthy subjects. Patients were grouped according to the extent of burn and to any sepsis on day 7. Expression and binding capacity of GR were determined as arbitrary units using flow cytometry.

RESULTS

GR expression and binding capacity were increased compared to healthy subjects in most circulating leucocyte subsets on admission irrespective of burn size. Patients with sepsis on day 7 displayed increased GR expression in T lymphocytes (51.8%, P < 0.01) compared to admission. There was a negative correlation between GR binding capacity in neutrophils and burn size after 14 days (P < 0.05).

CONCLUSIONS

GR expression and binding capacity are increased in most types of circulating leucocytes of severely burned patients on their admission to specialized burn care. If sepsis is present after 1 week, it is associated with higher GR expression in T lymphocytes and NK cells.

New insights into the controversy of adrenal function during critical illness

Critical illness represents a life-threatening disorder necessitating recruitment of defence mechanisms for survival. Herein, the hypothalamic-pituitary-adrenal axis is essential. However, the relevance of a relative insufficiency of the hypothalamic-pituitary-adrenal axis in critical illness, which is diagnosed by a suppressed cortisol response to exogenous adrenocorticotropic hormone (ACTH) irrespective of the plasma cortisol concentration, is controversial. Findings from several studies have provided insights that clarify at least part of this controversy. Rather than an activated hypothalamic-pituitary-adrenal axis, ACTH-independent regulators have been reported to contribute to increased cortisol availability during critical illness. One of these regulators is reduced cortisol breakdown, mediated by suppressed expression and activity of cortisol metabolising enzymes in the liver and kidneys. This downstream mechanism increases concentrations of plasma cortisol, but the ensuing feedback-inhibited ACTH release, when sustained for more than 1 week, has been shown to negatively affect adrenocortical integrity and function. Reduced adrenocortical ACTH signalling could explain reduced cortisol responses to exogenous ACTH. Whether such reduced cortisol responses in the presence of raised plasma (free) cortisol identifies adrenal failure needing treatment is unlikely. Additionally, reduced cortisol breakdown affects the optimum dose of hydrocortisone treatment during critical illness. Identification of patients with an insufficient hypothalamic-pituitary-adrenal axis response and the optimum treatment for this disorder clearly need more well designed preclinical and clinical studies.

Glucocorticoid Receptor Expression in Peripheral WBCs of Critically Ill Children

OBJECTIVES

To characterize glucocorticoid receptor expression in peripheral WBCs of critically ill children using flow cytometry.

DESIGN

Prospective observational cohort.

SETTING

A university-affiliated, tertiary PICU.

PATIENTS

Fifty-two critically ill children.

INTERVENTIONS

Samples collected for measurement of glucocorticoid receptor expression and parallel cortisol levels.

MEASUREMENTS AND MAIN RESULTS

Subjects with cardiovascular failure had significantly lower glucocorticoid receptor expression both in CD4 lymphocytes (mean fluorescence intensity, 522 [354-787] vs 830 [511-1,219]; p = 0.036) and CD8 lymphocytes (mean fluorescence intensity, 686 [350-835] vs 946 [558-1,511]; p = 0.019) compared with subjects without cardiovascular failure. Subjects in the upper 50th percentile of Pediatric Risk of Mortality III scores and organ failure also had significantly lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. There was no linear correlation between cortisol concentrations and glucocorticoid receptor expression.

CONCLUSIONS

Our study suggests that patients with shock and increased severity of illness have lower glucocorticoid receptor expression in CD4 and CD8 lymphocytes. Glucocorticoid receptor expression does not correlate well with cortisol levels. Future studies could focus on studying glucocorticoid receptor expression variability and isoform distribution in the pediatric critically ill population as well as on different strategies to optimize glucocorticoid response.

Evaluation of adrenal function in critically ill children

OBJECTIVE

There is no consensus on adequate adrenal response to critical illness. We aimed to evaluate adrenal function in critically ill children and its association with clinical outcome. We hypothesized that salivary cortisol would be a more appropriate tool to evaluate adrenal function in critically ill children.

METHODS

This was a prospective cohort study. The concentrations of serum total and salivary cortisol were measured in 34 critically ill children before and after stimulation with 250 μg adrenocorticotropic hormone (ACTH), and values were compared to a control group of healthy children (n = 15). Association between outcome and adrenal insufficiency defined by an increment in serum cortisol ≤250 nm (9 μg/dl) post-ACTH was assessed.

RESULTS

Serum total and salivary cortisol concentrations pre- and post-ACTH were significantly higher in patients, and they were correlated at baseline (r = 0·67; P < 0·0001) and after ACTH (r = 0·41; P = 0·02). The incidence of adrenal insufficiency was 32·3%. This group had higher Paediatric Risk of Mortality III score (P = 0·04) but Paediatric Logistic Organ Dysfunction and vasoactive inotropic scores, duration of mechanical ventilation and length of paediatric intensive care unit and hospital stay were not significantly different compared with those with an increment >250 nm (9 μg/dl) post-ACTH. An inverse correlation between salivary cortisol post-ACTH and vasoactive inotropic score (r = -0·56; P = 0·0008) was observed. A salivary cortisol concentration post-ACTH of ≤226 nm (8·2 μg/dl) had a sensitivity of 79% and a specificity of 62% to discriminate need for vasoactive or inotropic support (area under receiver operating characteristic (ROC) curve 0·74).

CONCLUSION

Adrenal insufficiency defined by the 'delta criterion' was not associated with outcome. A post-ACTH salivary cortisol of ≤226 nm (8·2 μg/dl) may be suggestive of an insufficient adrenal response to critical illness.

Critical illness-related corticosteroid insufficiency in children

Adequate adrenocortical function is essential for survival in critical illness. Most critically ill patients display elevated plasma cortisol concentrations, which reflects activation of the hypothalamic-pituitary-adrenal axis and is considered to be a homeostatic adaptation. However, many critically ill patients have 'relative' or 'functional' adrenal insufficiency, which is characterized by an inadequate production of cortisol in relation to an increased demand during periods of severe stress. Recently, the term 'critical illness-related corticosteroid insufficiency' (CIRCI) was coined. CIRCI occurs as a result of a decrease in adrenal steroid production or tissue resistance to glucocorticoids. An international task force of the American College of Critical Care Medicine issued recommendations for the diagnosis and management of this condition in adult patients. We review the prevalence, diagnosis, and therapeutic approach to adrenal insufficiency in critically ill children. We found a lack of consensus within the pediatric field as to the optimal approach to CIRCI, and call for an international task force to establish unified guidelines.

Cortisol metabolism in critical illness: implications for clinical care

PURPOSE OF REVIEW

Critical illness is uniformly characterized by elevated plasma cortisol concentrations, traditionally attributed exclusively to increased cortisol production driven by an activated hypothalamic pituitary adrenal axis. However, as plasma adrenocorticotropic hormone (ACTH) concentrations are often not elevated or even low during critical illness, alternative mechanisms must contribute.

RECENT FINDINGS

Recent investigations revealed that plasma clearance of cortisol is markedly reduced during critical illness, explained by suppressed expression and activity of the main cortisol metabolizing enzymes in liver and kidney. Furthermore, unlike previously inferred, cortisol production rate in critically ill patients was only moderately increased to less than double that of matched healthy subjects. In the face of low-plasma ACTH concentrations, these data suggest that other factors drive hypercortisolism during critical illness, which may suppress ACTH by feedback inhibition. These new insights add to the limitations of the current diagnostic tools to identify patients at risk of failing adrenal function during critical illness. They also urge to investigate the impact of lower hydrocortisone doses than those hitherto used.

SUMMARY

Recent novel insights reshape the current understanding of the hormonal stress response to critical illness and further underline the need for more studies to unravel the pathophysiology of adrenal (dys)functioning during critical illness.

Endocrine responses to critical illness: novel insights and therapeutic implications

CONTEXT

Critical illness, an extreme form of severe physical stress, is characterized by important endocrine and metabolic changes. Due to critical care medicine, survival from previously lethal conditions has become possible, but many patients now enter a chronic phase of critical illness. The role of the endocrine and metabolic responses to acute and prolonged critical illness in mediating or hampering recovery remains highly debated.

EVIDENCE ACQUISITION

The recent literature on changes within the hypothalamic-pituitary-thyroid axis and the hypothalamic-pituitary-adrenal axis and on hyperglycemia in relation to recovery from critical illness was critically appraised and interpreted against previous insights. Possible therapeutic implications of the novel insights were analyzed. Specific remaining questions were formulated.

EVIDENCE SYNTHESIS

In recent years, important novel insights in the pathophysiology and the consequences of some of these endocrine responses to acute and chronic critical illness were generated. Acute endocrine adaptations are directed toward providing energy and substrates for the vital fight-or-flight response in a context of exogenous substrate deprivation. Distinct endocrine and metabolic alterations characterize the chronic phase of critical illness, which seems to be no longer solely beneficial and could hamper recovery and rehabilitation.

CONCLUSIONS

Important novel insights reshape the current view on endocrine and metabolic responses to critical illness and further clarify underlying pathways. Although many issues remain unresolved, some therapeutic implications were already identified. More work is required to find better treatments, and the optimal timing for such treatments, to further prevent protracted critical illness, to enhance recovery thereof, and to optimize rehabilitation.

Measurement of the glucocorticoid receptor: relevance to the diagnosis of critical illness-related corticosteroid insufficiency in children

Diagnosis and management of critical illness-related corticosteroid insufficiency (CIRCI) in children continues to remain difficult and controversial in that no consensus for either exists among pediatric critical care physicians. Critical illness-related corticosteroid insufficiency is defined as a corticosteroid response that is inadequate for the severity of the illness experienced by the patient. Critical illness-related corticosteroid insufficiency manifests as an insufficient corticosteroid mediated down-regulation of proinflammatory cytokines, due to either corticosteroid tissue resistance and/or inadequate circulating levels of cortisol. The tissue resistance is likely due to alterations in the functionality of the intracellular receptor for corticosteroids, the glucocorticoid receptor (GR). This article details the role of the GR during critical illness with a focus upon the measurement of the GR, as a potentially important means by which to clinically assess the level of corticosteroid tissue-resistant in patients suspected of CIRCI. Measurement of the GR may be particularly useful as a means by which to determine the judicious administration of steroids, maximizing their therapeutic potential, whereas minimizing the morbidity that can be associated with their use.