Critically ill patients have high basal growth hormone levels with attenuated oscillatory activity associated with low levels of insulin-like growth factor-I

Establishing Predictors of Acute Sarcopenia: A Proof-Of-Concept Study Utilising Network Analysis

Dynamic changes in sarcopenia status following stressor events are defined as acute sarcopenia; it is currently unknown how to stratify risk. Prospective observational study involving elective colorectal surgery, emergency abdominal surgery, and medical patients with infections aged ≥70 years-old. Handgrip strength, muscle quantity (ultrasound Bilateral Anterior Thigh Thickness, BATT, and Bioelectrical Impedance Analysis), and muscle quality (rectus femoris echogenicity) were measured preoperatively in the elective group, and within 48hours, 7days after, and 13weeks after admission/surgery. Serum/plasma samples were collected preoperatively (elective group) and within 48hours of admission/surgery (all groups). LASSO models adjusting for baseline sarcopenia status were performed. Seventy-nine participants were included (mean age 79.1, 39.2% female). Chronic Obstructive Pulmonary Disease (COPD) (48hours β 0.67, CI 0.59-0.75), and prescription of steroids during admission (48hours β 1.11, CI 0.98-1.24) were positively associated with sarcopenia at 7days. Delirium was negatively associated with change in BATT to 7days (7days β -0.47, CI -0.5- -0.44). COPD (Preoperative β 0.35, CI 0.12-0.58) and delirium (48hours β 0.13, CI 0.06-0.2) were positively associated with change in echogenicity to 7days in analysis including systemic biomarkers. Participants with sarcopenia at baseline had higher IL-7 concentrations during acute phase of illness (median 8.78pg/mL vs 6.52pg/mL; p=0.014). IL-1b within 48hours of admission/surgery was positively associated with sarcopenia status at 7days (β 0.24, CI 0.06-0.42). Patients most at risk of acute sarcopenia or reductions in muscle quantity and quality included those prescribed steroids, with COPD or delirium, or with heightened systemic inflammation.

Novel insights in endocrine and metabolic pathways in sepsis and gaps for future research

Sepsis is defined as any life-threatening organ dysfunction caused by a dysregulated host response to infection. It remains an important cause of critical illness and has considerable short- and long-term morbidity and mortality. In the last decades, preclinical and clinical research has revealed a biphasic pattern in the (neuro-)endocrine responses to sepsis as to other forms of critical illness, contributing to development of severe metabolic alterations. Immediately after the critical illness-inducing insult, fasting- and stress-induced neuroendocrine and cellular responses evoke a catabolic state in order to provide energy substrates for vital tissues, and to concomitantly activate cellular repair pathways while energy-consuming anabolism is postponed. Large randomized controlled trials have shown that providing early full feeding in this acute phase induced harm and reversed some of the neuro-endocrine alterations, which suggested that the acute fasting- and stress-induced responses to critical illness are likely interlinked and benefical. However, it remains unclear whether, in the context of accepting virtual fasting in the acute phase of illness, metabolic alterations such as hyperglycemia are harmful or beneficial. When patients enter a prolonged phase of critical illness, a central suppression of most neuroendocrine axes follows. Prolonged fasting and central neuroendocrine suppression may no longer be beneficial. Although pilot studies have suggested benefit of fasting-mimicking diets and interventions that reactivate the central neuroendocrine suppression selectively in the prolonged phase of illness, further study is needed to investigate patient-oriented outcomes in larger randomized trials.

Impact of serum insulin-like growth factor-1 on HSCT outcome in pediatric cancer patients

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is associated with severe medical complications and variable outcome depending on the recipient's disease stage and health condition. Biomarkers predicting outcome may have therapeutic relevance in pediatric cancer care. Insulin like growth factor 1 (IGF 1) is a mitogenic and anabolic peptide hormone that is expressed in almost all tissues. This hormone is the major growth factor in childhood. As IGF 1 is decreased in conditions that cause catabolic metabolism, it may reflect the degree of physical robustness of the patient and serve as predictive biomarker for transplant outcome.

OBJECTIVES AND STUDY DESIGN

We evaluated the impact of pre-transplant serum-IGF 1 on both survival and adverse events in 587 pediatric cancer patients, who underwent autologous or allogeneic HSCT between 1987 and 2014 at the University Children's Hospital Tübingen, Germany. Survival probabilities of the entire cohort and of defined subgroups according to pre-transplant serum-IGF-1 were estimated using the Kaplan-Meier method.

RESULTS

Mean pre-transplant IGF 1 (n = 498) was low: -1.67 SDS (SD, 1.54). Completeness of follow-up three and ten years post HSCT was 96 % and 83 %, respectively. The ten-year overall survival was 44.8 % (95 % confidence interval [CI], 40.6-48.9). With decreasing IGF-1 SDS, there was a significant increase of transplant-related mortality (p = 0.027), sinusoidal obstruction syndrome (quartiles 4 to 1: 3; 1; 12; 12%; p < 0.001) and thrombotic microangiopathy (quartiles 4 to 1: 0: 0: 2; 5%; p = 0.004). IGF 1 decile 1 showed a significantly poorer outcome (p=0.042) with lower median (12 versus 68 months) and ten-year overall survival (37 % versus 52 %) when compared to decile 2-10.

CONCLUSIONS

This retrospective study suggests pre-transplant serum-IGF 1 as a predictor of survival and selected vascular adverse events that may have diagnostic and therapeutic relevance in pediatric cancer care.

Persisting neuroendocrine abnormalities and their association with physical impairment 5 years after critical illness

Background

Critical illness is hallmarked by neuroendocrine alterations throughout ICU stay. We investigated whether the neuroendocrine axes recover after ICU discharge and whether any residual abnormalities associate with physical functional impairments assessed 5 years after critical illness.

Methods

In this preplanned secondary analysis of the EPaNIC randomized controlled trial, we compared serum concentrations of hormones and binding proteins of the thyroid axis, the somatotropic axis and the adrenal axis in 436 adult patients who participated in the prospective 5-year clinical follow-up and who provided a blood sample with those in 50 demographically matched controls. We investigated independent associations between any long-term hormonal abnormalities and physical functional impairments (handgrip strength, 6-min walk distance, and physical health-related quality-of-life) with use of multivariable linear regression analyses.

Results

At 5-year follow-up, patients and controls had comparable serum concentrations of thyroid-stimulating hormone, thyroxine (T₄), triiodothyronine (T₃) and thyroxine-binding globulin, whereas patients had higher reverse T₃ (rT₃, p = 0.0002) and lower T₃/rT₃ (p = 0.0012) than controls. Patients had comparable concentrations of growth hormone, insulin-like growth factor-I (IGF-I) and IGF-binding protein 1 (IGFBP1), but higher IGFBP3 (p = 0.030) than controls. Total and free cortisol, cortisol-binding globulin and albumin concentrations were comparable for patients and controls. A lower T₃/rT₃ was independently associated with lower handgrip strength and shorter 6-min walk distance (p ≤ 0.036), and a higher IGFBP3 was independently associated with higher handgrip strength (p = 0.031).

Conclusions

Five years after ICU admission, most hormones and binding proteins of the thyroid, somatotropic and adrenal axes had recovered. The residual long-term abnormality within the thyroid axis was identified as risk factor for long-term physical impairment, whereas that within the somatotropic axis may be a compensatory protective response. Whether targeting of the residual abnormality in the thyroid axis may improve long-term physical outcome of the patients remains to be investigated.

Trial registration ClinicalTrials.gov: NCT00512122, registered on July 31, 2007 (https://www.clinicaltrials.gov/ct2/show/NCT00512122).

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-021-03858-1.

The antagonistic pleiotropy of insulin-like growth factor 1

While insulin-like growth factor-1 (IGF-1) is a well-established modulator of aging and longevity in model organisms, its role in humans has been controversial. In this study, we used the UK Biobank (n = 440,185) to resolve previous ambiguities in the relationship between serum IGF-1 levels and clinical disease. We examined prospective associations of serum IGF-1 with mortality, dementia, vascular disease, diabetes, osteoporosis, and cancer, finding two generalized patterns: First, IGF-1 interacts with age to modify risk in a manner consistent with antagonistic pleiotropy; younger individuals with high IGF-1 are protected from disease, while older individuals with high IGF-1 are at increased risk for incident disease or death. Second, the association between IGF-1 and risk is generally U-shaped, indicating that both high and low levels of IGF-1 may be detrimental. With the exception of a more uniformly positive relationship between IGF-1 and cancer, these effects were remarkably consistent across a wide range of conditions, providing evidence for a unifying pathway that determines risk for most age-associated diseases. These data suggest that IGF-1 signaling could be harmful in older adults, who may actually benefit from the attenuation of biological growth pathways.

IGF-1 and IGFBP-3 in Inflammatory Cachexia

Inflammation induces a wide response of the neuroendocrine system, which leads to modifications in all the endocrine axes. The hypothalamic–growth hormone (GH)–insulin-like growth factor-1 (IGF-1) axis is deeply affected by inflammation, its response being characterized by GH resistance and a decrease in circulating levels of IGF-1. The endocrine and metabolic responses to inflammation allow the organism to survive. However, in chronic inflammatory conditions, the inhibition of the hypothalamic–GH–IGF-1 axis contributes to the catabolic process, with skeletal muscle atrophy and cachexia. Here, we review the changes in pituitary GH secretion, IGF-1, and IGF-1 binding protein-3 (IGFBP-3), as well as the mechanism that mediated those responses. The contribution of GH and IGF-1 to muscle wasting during inflammation has also been analyzed.

Copeptin and stress-induced hyperglycemia in critically ill patients: A prospective study

Objectives

Copeptin, an equimolar indicator of serum antidiuretic hormone levels, has been associated with higher mortality in critically ill patients and with the development of diabetes in the general population. The aim of the present study was to investigate the association of copeptin levels with glycemic parameters in critically ill patients and to compare the time-course of copeptin in survivors and non-survivors.

Design

Prospective cohort study.

Patients

From June to October 2019, critically ill patients were prospectively enrolled and followed for 90 days.

Measurements

Plasma copeptin levels were determined at intensive care unit (ICU) admission (copeptin T1), 24 h (copeptin T2), and 48 h (copeptin T3) after study entry. Blood glucose and glycated hemoglobin levels were measured. ICU, in-hospital, and 90-day mortality, and length of stay in the ICU and hospital were evaluated.

Results

104 patients were included. No significant correlation was detected between copeptin levels and blood glucose (r = -0.17, p = 0.09), HbA1c (r = 0.01, p = 0.9), glycemic gap (r = -0.16, p = 0.11), and stress hyperglycemia ratio (r = -0.14, p = 0.16). Copeptin T3 levels were significantly higher in survivors than in non-survivors at hospital discharge (561 [370–856] vs 300 [231–693] pg/mL, p = 0.015) and at 90 days (571 [380–884] vs 300 [232–698] pg/mL, p = 0.03).

Conclusions

No significant correlations were found between copeptin levels and glycemic parameters, suggesting that copeptin is not a relevant factor in the induction of hyperglycemia during critical illness. Copeptin levels at ICU day 3 were higher in survivors than in non-survivors.

Endocrine Dysfunction in Traumatic Subarachnoid Hemorrhage: A Prospective Study

Background This study has prospectively investigated pituitary function and their correlation with severity, pressure effect, and Glasgow outcome scale in the acute phase of traumatic subarachnoid hemorrhage (SAH). Most of the retrospective studies have demonstrated that traumatic SAH-mediated hypopituitarism could be more frequent than previously known.

Objectives The aim of the study is to find the prevalence of endocrine dysfunction in traumatic SAH and its correlation with severity of injury and final outcome.

Materials and Methods Eighty-four consecutive patients of traumatic SAH formed the study group. Apart from clinical assessment, noncontrast computed tomography of the head was performed on all patients on admission. The hormonal analysis (FT3, FT4, thyroid-stimulating hormone, growth hormone [GH], cortisol, prolactin, testosterone) was performed within 24 hours of traumatic brain injury and was repeated on the seventh day amongst the patients who survived.

Results Most common hormone to increase on day one was cortisol (48.78%), while on day seven follicle-stimulating hormones and cortisol (15.38%) showed increment in levels. Most common hormone to decrease on day one was FT3 (36.84%) and GH (36.26%), while on day seven testosterone (66.67%) and FT4 (30.76%) showed decreasing levels. Hormone most resistant to change was prolactin.

Conclusion Hormonal dysfunction is common in moderate to severe traumatic brain injury. There is a direct association between radiological grading (Fischer) of SAH and hormonal profile changes. Performance of hormonal analysis should be considered in patients with moderate to severe traumatic brain injury, preferably with high-grade SAH, so that appropriate hormonal replacement can be done to optimize the clinical outcome.

Delirium, insulin-like growth factor I, growth hormone in older inpatients

BACKGROUND

Delirium is a common disorder in elderly medical inpatients with serious adverse outcomes and is characterized by sudden onset, disturbance in attention, awareness, consciousness and cognition, and often with behavioural disturbances. Central to understanding delirium, is understanding mechanisms by which body and brain wellbeing are linked and in particular how brain responses to bodily homeostatic stress is mediated. A number of studies have investigated the relationship between insulin-like growth factor I (IGF-I) and delirium in medically ill hospitalised patients with conflicting results. However, none have investigated growth hormone (GH) which is related to IGF-I via negative feedback.

AIM

To investigate the relationship between serum levels of IGF-I and GH, and the occurrence of delirium.

METHODS

Prospective, longitudinal, observational study. Consecutive elderly inpatients (aged 70+), were assessed twice weekly with Montreal cognitive assessment (MoCA), Confusion assessment method (CAM), Acute Physiology and Chronic Health Evaluation II. Delirium was defined using CAM. Previous history of dementia was evaluated with the Informant Questionnaire on Cognitive Decline in the Elderly. IGF-I and GH levels were estimated with the ELISA method. Generalized estimating equations (GEE) model was applied for the first five assessments to analyze those longitudinal data.

RESULTS

The sample consisted of 198 participants (mean age 80.63 ± 6.81; range 70-97). Of these 92 (46.5%) were females. Eighty six (43.4%) were identified with a history of dementia. Incident or prevalent delirium during hospitalisation was identified with CAM in 40 participants (20.2%). Evaluation of missing values with Little's MCAR test indicated that they were missing completely at random (MCAR χ² = 12.24, u: 9, P = 0.20). Using GEE for the analysis we found that low MoCA scores, low levels of IGF-I and high levels of GH were significantly associated with any delirium (prevalence, incident, or fluctuating , during the study period (Wald χ² = 12.231; u: 1, P < 0.001, Wald χ² = 7.196, u: 1, P = 0.007, Wald χ² = 6.210; : u: 1, P = 0.013 respectively).

CONCLUSION

The results show that low levels of IGF-I, high levels of GH and low scores in cognition are independently associated with the occurrence of any delirium during the hospitalisation of medically ill older people. The results of the study supports the hypothesis that deficits in the immunoreactivity of the brain (low cerebral reserve) may be associated with delirium.

Insulin-like Growth Factor-1 and IGF Binding Proteins Predict All-Cause Mortality and Morbidity in Older Adults

While the growth hormone/insulin-like growth factor-1 (GH/IGF-1) pathway plays essential roles in growth and development, diminished signaling via this pathway in model organisms extends lifespan and health-span. In humans, circulating IGF-1 and IGF-binding proteins 3 and 1 (IGFBP-3 and 1), surrogate measures of GH/IGF-1 system activity, have not been consistently associated with morbidity and mortality. In a prospective cohort of independently-living older adults (n = 840, mean age 76.1 ± 6.8 years, 54.5% female, median follow-up 6.9 years), we evaluated the age- and sex-adjusted hazards for all-cause mortality and incident age-related diseases, including cardiovascular disease, diabetes, cancer, and multiple-domain cognitive impairment (MDCI), as predicted by baseline total serum IGF-1, IGF-1/IGFBP-3 molar ratio, IGFBP-3, and IGFBP-1 levels. All-cause mortality was positively associated with IGF-1/IGFBP-3 molar ratio (HR 1.28, 95% CI 1.05–1.57) and negatively with IGFBP-3 (HR 0.82, 95% CI 0.680–0.998). High serum IGF-1 predicted greater risk for MDCI (HR 1.56, 95% CI 1.08–2.26) and composite incident morbidity (HR 1.242, 95% CI 1.004–1.538), whereas high IGFBP-1 predicted lower risk for diabetes (HR 0.50, 95% CI 0.29–0.88). In conclusion, higher IGF-1 levels and bioavailability predicted mortality and morbidity risk, supporting the hypothesis that diminished GH/IGF-1 signaling may contribute to human longevity and health-span.

The GH Axis in Relation to Accepting an Early Macronutrient Deficit and Outcome of Critically Ill Patients

CONTEXT

Changes in the GH axis during critical illness resemble fasting in healthy adults and contribute to hypercatabolism, which potentially affects outcome. Accepting macronutrient deficits by withholding parenteral nutrition (PN) during the first week in the intensive care unit (ICU; late PN) reduced complications and accelerated recovery as compared with early use of PN (early PN).

OBJECTIVE

To investigate how late PN affects the GH axis in relation to its clinical outcome benefits.

DESIGN

Preplanned subanalysis of the Early Parenteral Nutrition Completing Enteral Nutrition in Adult Critically Ill Patients randomized controlled trial.

PARTICIPANTS

A total of 1128 patients for time-course study, 20 patients investigated for nocturnal GH pulsatility, and 600 patients investigated for muscle weakness, with early PN and late PN patients having comparable baseline characteristics.

INTERVENTION

Withholding PN during the first ICU week (late PN) vs early PN.

MAIN OUTCOME MEASURES

Changes in serum GH, IGF-I, IGF-binding protein (IGFBP) 3, and IGFBP1 concentrations from ICU admission to day 4 or last ICU day for patients with a shorter ICU stay (d4/LD) and association in multivariable analyses with likelihood of earlier live ICU discharge, risk of new infection, and muscle weakness.

RESULTS

Late PN attenuated a rise in serum GH and IGF-I (P < 0.0001), did not affect IGFBP3, and attenuated a decrease in IGFBP1 concentrations from admission to d4/LD (P < 0.0001) as compared with early PN. Late PN decreased nonpulsatile (P = 0.005), but not pulsatile, GH secretion. Adjusting the multivariable models for the observed GH axis alterations increased the independent benefit of late PN for all outcomes. GH axis alterations induced by late PN were independently associated with adverse outcomes (P ≤ 0.03).

CONCLUSION

Accepting macronutrient deficits early during critical illness further suppressed the GH axis, which statistically attenuated its clinical outcome benefits.

Anterior pituitary function in critical illness

Critical illness is hallmarked by major changes in all hypothalamic-pituitary-peripheral hormonal axes. Extensive animal and human studies have identified a biphasic pattern in circulating pituitary and peripheral hormone levels throughout critical illness by analogy with the fasting state. In the acute phase of critical illness, following a deleterious event, rapid neuroendocrine changes try to direct the human body toward a catabolic state to ensure provision of elementary energy sources, whereas costly anabolic processes are postponed. Thanks to new technologies and improvements in critical care, the majority of patients survive the acute insult and recover within a week. However, an important part of patients admitted to the ICU fail to recover sufficiently, and a prolonged phase of critical illness sets in. This prolonged phase of critical illness is characterized by a uniform suppression of the hypothalamic-pituitary-peripheral hormonal axes. Whereas the alterations in hormonal levels during the first hours and days after the onset of critical illness are evolutionary selected and are likely beneficial for survival, endocrine changes in prolonged critically ill patients could be harmful and may hamper recovery. Most studies investigating the substitution of peripheral hormones or strategies to overcome resistance to anabolic stimuli failed to show benefit for morbidity and mortality. Research on treatment with selected and combined hypothalamic hormones has shown promising results. Well-controlled RCTs to corroborate these findings are needed.

Benchmarking clinical outcomes and the immunocatabolic phenotype of chronic critical illness after sepsis in surgical intensive care unit patients

BACKGROUND

A growing number of patients survive sepsis but remain chronically critically ill. We sought to define clinical outcomes and incidence of chronic critical illness (CCI) after sepsis and to determine whether selected biomarkers of inflammation, immunosuppression, and catabolism differ between these patients and those that rapidly recover (RAP).

METHODS

This 3-year prospective observational cohort study (NCT02276417) evaluated 145 surgical intensive care unit patients with sepsis for the development of CCI (≥14 days of intensive care unit resource utilization with persistent organ dysfunction). Patient clinical demographics, outcomes, and serial serum/urine samples were collected for plasma protein and urinary metabolite analyses.

RESULTS

Of 145 sepsis patients enrolled, 19 (13%) died during their hospitalization and 71 (49%) developed CCI. The CCI patients were significantly older (mean, 63 ± 15 vs. 58 ± 13 years, p = 0.006) and more likely to be discharged to long-term acute care facilities (32% vs. 3%, p < 0.0001), whereas those with RAP were more often discharged to home or a rehabilitation facility. Six-month mortality was significantly higher in CCI as compared with RAP cohort (37% vs. 2%; p < 0.01). Multivariate logistic regression modeling revealed delayed onset sepsis (>48 hours after admission; odds ratio [OR], 10.93; 95% confidence interval [CI], 4.15-28.82]), interfacility transfer (OR, 3.58; 95% CI, 1.43-8.96), vasopressor-dependent septic shock (OR, 3.75; 95% CI, 1.47-9.54), and Sequential Organ Failure Assessment score of 5 or greater at 72 hours (OR, 5.03; 95% CI, 2.00-12.62) as independent risk factors for the development of CCI. The CCI patients also demonstrated greater elevations in inflammatory cytokines (IL-6, IL-8, IL-10), and biomarker profiles are consistent with persistent immunosuppression (absolute lymphocyte count and soluble programmed death ligand 1) and catabolism (plasma insulin-like growth factor binding protein 3 and urinary 3-methylhistidine excretion).

CONCLUSION

The development of CCI has become the predominant clinical trajectory in critically ill surgical patients with sepsis. These patients exhibit biomarker profiles consistent with an immunocatabolic phenotype of persistent inflammation, immunosuppression, and catabolism.

LEVEL OF EVIDENCE

Prognostic, level II.

Effects of early administration of insulin-like growth factor-1 on cognitive function in septic encephalopathy

BACKGROUND

Both protective and therapeutic functions of insulin-like growth factor-1 (IGF-1) in brain injury have been reported, but its effects on cognitive sequelae after septic encephalopathy (SE) remain unclear.

MATERIALS AND METHODS

This study was divided into three parts, and a septic model was built by cecal ligation and puncture (CLP). First, survival analysis was performed, and IGF-1's effects on long-term cognition and depressive emotion were assessed. Second, the characteristics of IGF-1 function in cognition were evaluated. Finally, cytochrome C, caspase-9, tumor necrosis factor receptor (TNFR), and caspase-8 levels as well as cell apoptosis in the hippocampus were evaluated.

RESULTS

IGF-1 did not reduce mortality or alleviate depressive symptoms in septic rats, but improved the memory of noxious stimulation and spatial learning and memory. These effects were observed only when IGF-1 was administered within 0-6 hours after CLP. Moreover, cytochrome C and caspase-9 expression levels were increased at 6 hours after CLP in the hippocampus, while TNFR and caspase-8 amounts were not increased until 12 hours after CLP. Cell apoptosis increased at 12 hours after CLP, but was inhibited by IGF-1.

CONCLUSION

Cognitive impairment in rats recovering from SE is associated with cell apoptosis in the hippocampus. Supplementation of IGF-1 reduces cell apoptosis by preventing the over-expression of cytochrome C and TNFR, and results in improved cognitive function. However, improvement only occurs when IGF-1 is administered at the early stage (within 6 hours) of sepsis. As cytochrome C activation occurs earlier than that of TNFR in this study, cytochrome C may be the main factor inducing apoptosis in early SE.

Outcome of Critically ill Patients Undergoing Mandatory Insulin Therapy Compared to Usual Care Insulin Therapy: Protocol for a Pilot Randomized Controlled Trial

Background

Observational and interventional studies in patients with both acute medical conditions and long-standing diabetes have shown that improved blood glucose control confers a survival advantage or reduces complication rates. Policies of “tight” glycaemic control were rapidly adopted by many general intensive care units (ICUs) worldwide in the mid 00’s, even though the results of the studies were not generalizable to mixed medical/surgical ICUs with different intravenous feeding policies.

Objective

The primary objective of the study is to assess the safety of mandatory insulin infusion in critically ill patients in a general ICU setting.

Methods

This protocol summarizes the rationale and design of a randomized, controlled, single-center trial investigating the effect of mandatory insulin therapy versus usual care insulin therapy for those patients admitted for a stay of longer than 48 hours. In total, 109 critically ill adults predicted to stay in intensive care for longer than 48 hours consented. The primary outcome is to determine the safety of mandatory insulin therapy in critically ill patients using the number of episodes of hypoglycaemia and hypokalaemia per unit length of stay in intensive care. Secondary outcomes include the duration of mechanical ventilation, duration of ICU and hospital stay, hospital mortality, and measures of renal, hepatic, and haematological dysfunction.

Results

The project was funded in 2005 and enrolment was completed 2007. Data analysis is currently underway and the first results are expected to be submitted for publication in 2018.

Conclusions

This protocol for a randomized controlled trial investigating the effect of mandatory insulin therapy should provide an answer to a key question for the management of patients in the ICU and ultimately improving outcome.

Trial Registration

International Standard Randomized Controlled Trial Number ISRCTN00550641; http://www.isrctn.com/ISRCTN00550641 (Archived at WebCite: http://www.webcitation.org/6xk8NXxNv).

Arginine reverses growth hormone resistance through the inhibition of toll-like receptor 4-mediated inflammatory pathway

OBJECTIVE

Growth hormone stimulates growth by increasing insulin-like growth factor 1 expression and secretion. In the presence of insufficient nutrients, GH increases, whereas IGF-1 expression becomes severely suppressed, leading to GH resistance. This study aimed to explore the effect of arginine (Arg) on GH resistance during malnutrition and to describe its underlying mechanism.

METHODS

C57BL/6J mice were injected intraperitoneally with Arg for 1h or subjected to caloric restriction with Arg supplement in drinking water for 18days. HepG2 cells were exposed to different Arg concentrations for 24h. Signaling pathway agonists/inhibitors, siRNA, and overexpression plasmids were used to investigate the underlying molecular mechanism. Liver-specific toll-like receptor (TLR4) knockout mice were utilized to clarify the role of TLR4 in Arg-induced IGF-I expression and secretion.

RESULTS

Arg inhibited the TLR4 downstream pathway by binding to TLR4 and consequently activated Janus kinase 2/signal transducer and activator of transcription 5 signaling pathway. As a result, IGF-1 transcription and secretion increased. Arg activity was absent in liver-specific TLR4 knockout mice and was greatly suppressed in liver with overexpressed TLR4, suggesting that hepatic TLR4 was required and sufficient to induce GH resistance. By contrast, the mammalian target of rapamycin pathway was unnecessary for Arg activity. Arg not only significantly increased IGF-1 expression and secretion under acute fasting and chronic CR conditions but also attenuated body weight loss.

CONCLUSIONS

Our results demonstrate a previously unappreciated pathway involving Arg that reverses GH resistance and alleviates malnutrition-induced growth restriction through the inhibition of TLR4-mediated inflammatory pathway.

Biochemical investigations in diagnosis and follow up of acromegaly

Measurements of human growth hormone (GH) and insulin-like growth-factor I (IGF-I) are cornerstones in the diagnosis of acromegaly. Both hormones are also used as biochemical markers in the evaluation of disease activity during treatment. Management of acromegaly is particularly challenging in cases where discordant information is obtained from measurement of GH concentrations following oral glucose load and from measurement of IGF-I. While in some patients biological factors can explain the discrepancy, in many cases issues with the analytical methods seem to be responsible. Assays used by endocrine laboratories to determine concentrations of GH and IGF-I underwent significant changes during the last decades. While generally leading to more sensitive and reproducible methods, these changes also had considerable impact on absolute concentrations measured. This must be reflected by updated decision limits, cut-offs and reference intervals. Since different commercially available assays do not agree very well, method specific interpretation of GH and IGF-I concentrations is required. This complexity in the interpretation of hormone concentrations is not always appropriately reflected in laboratory reports, but also not in clinical guidelines reporting decision limits not related to a specific analytical method. The present review provides an overview about methodological and biological variables affecting the biochemical assessment of acromegaly in diagnosis and follow up.

Pituitary dysfunction in traumatic brain injury: Is evaluation in the acute phase worthwhile?

INTRODUCTION

Traumatic brain injury (TBI) is an under-recognized cause of hypopituitarism. According to recent data, it could be more frequent than previously known. However, there is a scarcity of data in Indian population.

AIMS

The main aim of the study was to determine the prevalence of pituitary hormone deficiencies in the acute phase of TBI. The secondary objectives were to correlate the severity of trauma with basal hormone levels and to determine whether initial hormone deficiencies predict mortality.

SUBJECTS AND METHODS

Forty-nine TBI patients (41 men and 8 women) were included in this study. Pituitary functions were evaluated within 24 h of admission.

RESULTS

Gonadotropin deficiency was found in 65.3% patient while 46.9% had low insulin-like growth factor-1, 12.24% had cortisol level <7 mcg/dl. Cortisol and prolactin level were positively correlated with the severity of TBI suggestive of stress response. Free triiodothyronine (fT3) and free thyroxine were significantly lower in patients with increasing severity of tuberculosis. Logistic regression analysis revealed that mortality after TBI was unrelated to the basal pituitary hormone levels except low T3 level, which was found to be positively related to mortality.

CONCLUSIONS

Pituitary dysfunction is common after TBI and the most commonly affected axes are growth hormone and gonadotropin axis. Low fT3 correlates best with mortality. During the acute phase of TBI, at least an assessment of cortisol is vital as undetected cortisol deficiency can be life-threatening.

Evaluation of endocrine function in children admitted to pediatric intensive care unit

BACKGROUND

Although studied widely in adulthood, little is known about endocrinological disorders during critical illnesses in childhood. The aims of this study were to define the endocrinological changes in patients admitted to pediatric intensive care unit (PICU) and to identify their effects on prognosis.

METHODS

Forty patients with a mean age of 5.1 years admitted to PICU were enrolled in the study. Blood samples were taken at admission and at 24 and 48 h to measure cortisol, adrenocorticotropic hormone (ACTH), prolactin, growth hormone (GH), GH binding protein (GHBP), insulin-like growth factor-binding protein-3 (IGFBP-3) and interleukin-6 (IL-6). The severity of the patient's condition was assessed using pediatric risk of mortality (PRISM) and pediatric logistic organ dysfunction (PELOD) scores.

RESULTS

PRISM and PELOD scores were significantly higher in non-survivors. Cortisol, ACTH, prolactin, GH, GHBP, IGFBP-3 and IL-6 were not significantly different between the survivors and non-survivors. There was a negative correlation between baseline IGFBP-3 and PRISM scores. A positive correlation was seen between cortisol level at 24 h and PRISM score. On multivariate linear regression analysis, PRISM score was best explained by ACTH and cortisol at 24 h. A positive weak correlation was detected between IL-6 at 24 h and PELOD scores.

CONCLUSIONS

Although there was no difference between survivors and non-survivors regarding the studied endocrine parameters, there were associations between cortisol, ACTH, IL-6 and IGFBP-3 and risk assessment scores, and, given that these scores correlated with mortality, these parameters might be useful as prognostic factors.

Prospective investigation of anterior pituitary function in the acute phase and 12 months after pediatric traumatic brain injury

PURPOSE

Although head trauma is common in childhood, there is no enough prospective study investigating both acute phase and 12 months after injury. Therefore, a prospective clinical trial was planned to evaluate the pituitary function in childhood in the acute and chronic phase after traumatic brain injury (TBI).

METHODS

Forty-one children (27 boys and 14 girls, mean age 7 ± 4.3), who were admitted to neurosurgery intensive care unit due to head trauma, were included. Twenty-one (51.2 %) patients had mild, 10 (24.4 %) had moderate, and 10 (24.4 %) had severe TBI. Twenty-two of them were reevaluated 12 months after TBI. Basal pituitary hormone levels were measured during acute (first 24 h) and chronic phase of TBI. Additionally, in the chronic phase, GHRH-arginine test was used for the diagnosis of growth hormone (GH) deficiency.

RESULTS

In the acute phase, 10 patients (24.4 %) had ACTH deficiency, and the overall 44.3 % of patients had at least one pituitary hormone dysfunction. All the pituitary hormone deficiencies during the acute phase were recovered after 12 months. Two patients (9.1 %) had new-onset GH deficiency in the chronic phase, and in one of them, ACTH deficiency was also present.

CONCLUSIONS

Present prospective data clearly demonstrated that most of the hormonal changes in the early acute phase were transient, suggesting an adaptive response, and these changes did not predict the hormone deficiencies after 1 year. In the chronic phase, although GH deficiency was present, the frequency of TBI-induced hypopituitarism was clearly lower than the adult patients.

Interaction of the endocrine system with inflammation: a function of energy and volume regulation

During acute systemic infectious disease, precisely regulated release of energy-rich substrates (glucose, free fatty acids, and amino acids) and auxiliary elements such as calcium/phosphorus from storage sites (fat tissue, muscle, liver, and bone) are highly important because these factors are needed by an energy-consuming immune system in a situation with little or no food/water intake (sickness behavior). This positively selected program for short-lived infectious diseases is similarly applied during chronic inflammatory diseases. This review presents the interaction of hormones and inflammation by focusing on energy storage/expenditure and volume regulation. Energy storage hormones are represented by insulin (glucose/lipid storage and growth-related processes), insulin-like growth factor-1 (IGF-1) (muscle and bone growth), androgens (muscle and bone growth), vitamin D (bone growth), and osteocalcin (bone growth, support of insulin, and testosterone). Energy expenditure hormones are represented by cortisol (breakdown of liver glycogen/adipose tissue triglycerides/muscle protein, and gluconeogenesis; water retention), noradrenaline/adrenaline (breakdown of liver glycogen/adipose tissue triglycerides, and gluconeogenesis; water retention), growth hormone (glucogenic, lipolytic; has also growth-related aspects; water retention), thyroid gland hormones (increase metabolic effects of adrenaline/noradrenaline), and angiotensin II (induce insulin resistance and retain water). In chronic inflammatory diseases, a preponderance of energy expenditure pathways is switched on, leading to typical hormonal changes such as insulin/IGF-1 resistance, hypoandrogenemia, hypovitaminosis D, mild hypercortisolemia, and increased activity of the sympathetic nervous system and the renin-angiotensin-aldosterone system. Though necessary during acute inflammation in the context of systemic infection or trauma, these long-standing changes contribute to increased mortality in chronic inflammatory diseases.

Hypothalamic-pituitary hormones during critical illness: a dynamic neuroendocrine response

Independent of the underlying condition, critical illness is characterized by a uniform dysregulation of the hypothalamic-pituitary-peripheral axes. In most axes a clear biphasic pattern can be distinguished. The acute phase of critical illness is characterized by low peripheral effector hormone levels such as T3, IGF-1 and testosterone, despite an actively secreting pituitary. The adrenal axis with high cortisol levels in the presence of low ACTH levels is a noteworthy exception. In the prolonged phase of critical illness, low peripheral effector hormone levels coincide with a uniform suppression of the neuroendocrine axes, predominantly of hypothalamic origin. The severity of the alterations in the different neuroendocrine axes is associated with a high risk of morbidity and mortality, but it remains unknown whether the observed changes are cause or consequence of adverse outcome. Several studies have identified therapeutic potential of hypothalamic releasing factors, but clinical outcome remains to be investigated with sufficiently powered randomized controlled trials.

Somatotropic and thyroid hormones in the acute phase of subarachnoid haemorrhage

BACKGROUND

Somatotropic and thyroid hormones are probably important for the recovery after acute brain injury. Still, the dynamics of these hormones after spontaneous subarachnoid haemorrhage (SAH) is not well described. The purpose of this study was to investigate the relation between somatotropic and thyroid hormones and clinical factors after SAH.

METHODS

Twenty patients with spontaneous SAH were included prospectively. Serum concentrations of TSH, fT4, T3, IGF-1 and GH were measured once a day for 7 days after SAH. Hormone patterns and serum concentrations were compared to the severity of SAH, neurological condition at admission, clinical course and outcome of the patients.

RESULTS

During the first week after SAH, all patients showed increased GH and IGF-1 concentrations. In the whole group, concentrations of TSH increased, whereas T3 and fT4 decreased. There were no relations of serum concentrations of IGF-1 or GH to clinical condition at admission, clinical course or outcome of the patients. Half of the patients showed low T3 serum concentrations. A complicated course was associated with a deeper fall in TSH and T3 concentrations. There were negative correlations for mean concentrations of TSH and T3 versus WFNS grade and a positive correlation for T3 versus GOS after 6 months, indicating that low concentrations of TSH and T3 were connected to worse SAH grade and poor outcome.

CONCLUSIONS

All patients showed increased GH and IGF-1 concentrations irrespective of the grade of SAH or clinical course. Patients with a complicated clinical course showed a more pronounced fall in TSH and T3 concentrations and low serum T3 concentrations were related to a more serious SAH and poor patient outcome. These results need to be studied further and they may contribute to the accumulated knowledge needed to understand the complex mechanisms influencing the unpredictable clinical course after SAH.

Insulin-like Growth Factor I and its binding protein 3 in sepsis

OBJECTIVE

To investigate the Growth Hormone (GH)/Insulin-like Growth Factor-I (IGF-I) axis and identify the factors that determine IGF-I levels in adult septic patients of variable severity, i.e., with sepsis, severe sepsis or septic shock, in the acute phase of disease.

DESIGN

In 107 consecutive septic patients (44 with sepsis, 13 with severe sepsis, and 50 with septic shock), GH, IGF-I, Insulin-like Growth Factor Binding Protein-3 (IGFBP-3), insulin, cortisol, albumin, thyroid hormones, C-reactive protein and interleukin-6 serum levels were measured once within 48 h after onset of a septic episode. Twenty-nine healthy volunteers served as controls.

RESULTS

IGF-I and IGFBP-3 levels were decreased in patients with sepsis and severe sepsis (versus controls), decreasing further in patients with septic shock (versus sepsis). IGF-I levels were positively related to IGFBP-3, albumin, triiodothyronine and thyroxine, and inversely related to cortisol, sepsis severity, C-reactive protein, interleukin-6 and age. In multiple regression analysis, IGF-I levels were independently related to IGFBP-3 and albumin (lower in patients with decreased IGFBP-3 and albumin levels) (p<0.001 and p=0.01, respectively), and cortisol (lower in patients with increased cortisol levels) (p=0.04). IGFBP-3 accounted for most of the variance explained by the model (R(2)=0.519). GH levels were not related to IGF-I levels or mortality. IGF-I and IGFBP-3 levels were not associated with mortality.

CONCLUSIONS

The GH/IGF-I axis is severely disrupted in septic patients. IGFBP-3 is the major determinant of IGF-I levels.

Hepatic growth hormone resistance after acute injury

Severe injury and infection are often followed by accelerated protein catabolism and acute insulin resistance. This results in several effects that complicate and prolong recovery, including weakness, immobility, impaired wound healing, and organ dysfunction. Recent studies have demonstrated the development of GH resistance during severe inflammation, providing a potential mechanism for the protein loss that follows injury and infection. To understand this GH resistance, we recently developed a murine model of acute injury. Mice were subjected to soft-tissue injury, alone or combined with hemorrhage, and injected iv with GH 30, 60, or 90 minutes later. Hepatic GH signaling was measured via Western analysis. GH-induced signal transducer and activator of transcription 5 phosphorylation was decreased immediately after completion of the trauma procedure, and at 30 and 60 minutes, but further decreased by 90 minutes after trauma. Combined trauma and hemorrhage resulted in severely decreased GH-induced signal transducer and activator of transcription 5 phosphorylation compared with trauma alone, and this was true at all time points studied. Western analysis revealed an apparent decrease in the molecular weight of the hepatic GH receptor (GHR) after trauma and hemorrhage, but not trauma alone. Additional studies determined that the hemorrhage-induced decrease in receptor size was not due to changes in GHR N-linked glycosylation. These results suggest that GH sensitivity is rapidly impaired after acute injury and that trauma combined with hemorrhage results in a more severe form of GH resistance resulting from alteration or inactivation of hepatic GHR.

Effect of tight glucose control with insulin on the thyroid axis of critically ill children and its relation with outcome

CONTEXT

Tight glucose control (TGC) to normal-for-age fasting blood glucose levels reduced morbidity and mortality in surgical adult and pediatric intensive care unit (ICU) patients. In adults, TGC did not affect the illness-induced alterations in thyroid hormones. With better feeding in children than in adult patients, we hypothesized that TGC in pediatric ICU patients reactivates the thyroid axis.

OBJECTIVE

The aim of this study was to assess the impact of TGC on the thyroid axis in pediatric ICU patients and to investigate how these changes affect the TGC outcome benefit.

DESIGN AND PATIENTS

We conducted a preplanned analysis of all patients not treated with thyroid hormone, dopamine, or corticosteroids who were included in a randomized controlled trial on TGC (n=700).

MAIN OUTCOME MEASURES

Serum TSH, T4, T3, and rT3 were measured upon admission and on ICU day 3 or the last ICU day for patients discharged earlier. Changes from baseline were compared for the TGC and usual care groups. The impact on the outcome benefit of TGC was assessed with multivariable Cox proportional hazard analysis, correcting for baseline risk factors.

RESULTS

TGC further lowered the T)/rT3 ratio (P=0.03), whereas TSH (P=0.09) and T4 (P=0.3) were unaltered. With TGC, the likelihood of earlier live discharge from the ICU was 19% higher at any time (hazard ratio, 1.190; 95% confidence interval, 1.010-1.407; P=0.03). This benefit was statistically explained by the further reduction of T3/rT3 with TGC because an increase in T3/rT3 was strongly associated with a lower likelihood for earlier live discharge (hazard ratio per unit increase, 0.863; 95% confidence interval, 0.806-0.927; P<0.0001).

CONCLUSIONS

TGC further accentuated the peripheral inactivation of thyroid hormone. This effect, mimicking a fasting response, statistically explained part of the clinical outcome benefit of TGC.

Mediation of vertebrate life histories via insulin-like growth factor-1

Life-history traits describe parameters associated with growth, size, survival, and reproduction. Life-history variation is a hallmark of biological diversity, yet researchers commonly observe that one of the major axes of life-history variation after controlling for body size involves trade-offs among growth, reproduction, and longevity. This persistent pattern of covariation among these specific traits has engendered a search for shared mechanisms that could constrain or facilitate production of variation in life-history strategies. Endocrine traits are one candidate mechanism that may underlie the integration of life history and other phenotypic traits. However, the vast majority of this research has been on the effects of steroid hormones such as glucocorticoids and androgens on life-history trade-offs. Here we propose an expansion of the focus on glucocorticoids and gonadal hormones and review the potential role of insulin-like growth factor-1 (IGF-1) in shaping the adaptive integration of multiple life-history traits. IGF-1 is a polypeptide metabolic hormone largely produced by the liver. We summarize a vast array of research demonstrating that IGF-1 levels are susceptible to environmental variation and that IGF-1 can have potent stimulatory effects on somatic growth and reproduction but decrease lifespan. We review the few studies in natural populations that have measured plasma IGF-1 concentrations and its associations with life-history traits or other characteristics of the organism or its environment. We focus on two case studies that found support for the hypothesis that IGF-1 mediates adaptive divergence in suites of life-history traits in response to varying ecological conditions or artificial selection. We also examine what we view as potentially fruitful avenues of research on this topic, which until now has been rarely investigated by evolutionary ecologists. We discuss how IGF-1 may facilitate adaptive plasticity in life-history strategies in response to early environmental conditions and also how selection on loci controlling IGF-1 signaling may mediate population divergence and eventual speciation. After consideration of the interactions among androgens, glucocorticoids, and IGF-1 we suggest that IGF-1 be considered a suitable candidate mechanism for mediating life-history traits. Finally, we discuss what we can learn about IGF-1 from studies in free-ranging animals. The voluminous literature in laboratory and domesticated animals documenting relationships among IGF-1, growth, reproduction, and lifespan demonstrates the potential for a number of new research questions to be asked in free-ranging animals. Examining how IGF-1 mediates life-history traits in free-ranging animals could lead to great insight into the mechanisms that influence life-history variation.

Insulin-like growth factor I and the pathogenesis of delirium: a review of current evidence

Delirium is a frequent complication in medically ill elderly patients that is associated with serious adverse outcomes including increased mortality. Delirium risk is linked to older age, dementia, and illness that involves activation of inflammatory responses. IGF-I is increasingly postulated as a key link between environmental influences on body metabolism with a range of neuronal activities and has been described as the master regulator of the connection between brain and bodily well-being. The relationships between IGF-I and ageing, cognitive impairment and inflammatory illness further support a possible role in delirium pathogenesis. Five studies of IGF-I in delirium were identified by a systematic review. These conflicting findings, with three of the five studies indicating an association between IGF-1 and delirium occurrence, may relate to the considerable methodological differences in these studies. The relevance of IGF-I and related factors to delirium pathogenesis can be clarified by future studies which account for these issues and other confounding factors. Such work can inform therapeutic trials of IGF-I and/or growth hormone administration.

Serum thyroid hormones levels are significantly decreased in septic neonates with poor outcome

The aim of this prospective study was to investigate the effects of thyroid hormone levels on the sepsis criteria and mortality in septic newborns. This study was performed at the Firat University Hospital Neonatal Intensive Care Unit. A group of septic newborns and a control group of healthy non-infected newborns were evaluated. Blood samples were obtained at onset from septic and healthy newborns and at 10th day of the antibiotic therapy from only septic newborns, and thereafter serum total T(3) (TT(3)), total T(4) (TT(4)), and TSH levels were determined. A total of 292 newborns were included in the study. Serum TT(3) levels at onset and at 10th day of the antibiotic therapy were 163.8±63.4 and 178.3±33.1 ng/dl, TT(4) levels were 6.9±2.2 and 11.0±2.6 mg/ml, and TSH levels were 3.8±2.1 and 4.0±2.5 μU/ml, respectively in septic newborns. Serum TT3 levels were 180.3±47.6 ng/dl, TT(4) levels were 10.9±2.3 mg/ml, and TSH levels were 4.1±2.2 μU/ml in healthy newborns. Serum TT(3), TT(4) levels of septic newborns were significantly decreased with respect to those of healthy newborns at onset and serum TT(4) levels was increased significantly after antibiotic therapy. To the best of our knowledge, this report is the first study to compare thyroid hormone levels in a large number of septic newborns and a healthy group. Our findings suggest that before and after treatment of neonatal sepsis a significant change is realized in thyroid hormone levels.

Performance-enhancing sports supplements: role in critical care

Many performance-enhancing supplements and/or drugs are increasing in popularity among professional and amateur athletes alike. Although the uncontrolled use of these agents can pose health risks in the general population, their clearly demonstrated benefits could prove helpful to the critically ill population in whom preservation and restoration of lean body mass and neuromuscular function are crucial. Post-intensive care unit weakness not only impairs post-intensive care unit quality of life but also correlates with intensive care unit mortality. This review covers a number of the agents known to enhance athletic performance, and their possible role in preservation of muscle function and prevention/treatment of post-intensive care unit weakness in critically ill patients. These agents include testosterone analogues, growth hormone, branched chain amino acid, glutamine, arginine, creatine, and beta-hydryoxy-beta-methylbutyrate. Three of the safest and most effective agents in enhancing athletic performance in this group are creatine, branched-chain amino acid, and beta-hydryoxy-beta-methylbutyrate. However, these agents have received very little study in the recovering critically ill patient suffering from post-intensive care unit weakness. More placebo-controlled studies are needed in this area to determine efficacy and optimal dosing. It is very possible that, under the supervision of a physician, many of these agents may prove beneficial in the prevention and treatment of post-intensive care unit weakness.

Nonthyroidal illness syndrome in children

Neuroendocrine changes in the hypothalamic-pituitary-thyroid axis during critical illness result in nonthyroidal illness syndrome (NTIS) characterized by abnormal thyrotropin (TSH) and thyroid hormone levels. Studies looking at the natural history of neuroendocrine changes during critical illness have revealed the presence of NTIS. NTIS has been described in a variety of patient settings. Many studies have tried to uncover the pathophysiology behind NTIS and several theories are proposed. Whether NTIS requires treatment or intervention is still controversial and the results of the treatment studies are arguably mixed. Whether implicitly stated or not, the underlying purpose of all the natural history, pathophysiology, or treatment studies is to determine whether NTIS is adaptive or maladaptive. Some studies have illustrated a correlation between illness severity and the degree of NTIS but a cause and effect relationship is still elusive. The human studies can be divided between those with either adult or pediatric subjects, with much less data available in the latter. This review examines the available literature on NTIS with an emphasis on the pediatric literature.

Inhibition of complement C5a prevents breakdown of the blood-brain barrier and pituitary dysfunction in experimental sepsis

Introduction

Septic encephalopathy secondary to a breakdown of the blood-brain barrier (BBB) is a known complication of sepsis. However, its pathophysiology remains unclear. The present study investigated the effect of complement C5a blockade in preventing BBB damage and pituitary dysfunction during experimental sepsis.

Methods

Using the standardised caecal ligation and puncture (CLP) model, Sprague-Dawley rats were treated with either neutralising anti-C5a antibody or pre-immune immunoglobulin (Ig) G as a placebo. Sham-operated animals served as internal controls.

Results

Placebo-treated septic rats showed severe BBB dysfunction within 24 hours, accompanied by a significant upregulation of pituitary C5a receptor and pro-inflammatory cytokine expression, although gene levels of growth hormone were significantly attenuated. The pathophysiological changes in placebo-treated septic rats were restored by administration of neutralising anti-C5a antibody to the normal levels of BBB and pituitary function seen in the sham-operated group.

Conclusions

Collectively, the neutralisation of C5a greatly ameliorated pathophysiological changes associated with septic encephalopathy, implying a further rationale for the concept of pharmacological C5a inhibition in sepsis.

Acromegaly with normal IGF-1 levels probably due to poorly controlled diabetes mellitus

Acromegaly is characterized by the somatic disfigurement and excessive production of growth hormone (GH) and insulin-like growth factor-1 (IGF-1). Here we report a patient with aromegaly and diabetes mellitus, who showed normal IGF-1 levels in spite of elevated GH levels. The patient was a 52-year-old woman with acromegalic manifestations. Serum GH level was elevated (32.4 ng/mL) with hyperglycemia (fasting plasma glucose, 277 mg/dL) and an extremely high level of glycosylated hemoglobin (HbA1c 17.7%), whereas serum IGF-1 level was within normal range (110 ng/mL, normal range 37-266). Brain magnetic resonance imaging detected a pituitary tumor, with involvement of the right cavernous sinus. Oral glucose tolerance test (OGTT) showed no suppression of serum GH. Thyrotropin-releasing hormone test showed paradoxical increases in serum GH. We therefore diagnosed acromegaly accompanied with diabetes mellitus. A large amount of insulin (34 units/day) was required to control the blood glucose level. The patient was treated with octreotide, a somatostatin analogue, followed by transsphenoidal surgery. After the surgery, serum GH levels were suppressed by OGTT, although basal serum GH levels remained to be high. Basal serum GH levels, however, were normalized 5 months later. Blood glucose became well controlled by the diet alone. In contrast, serum IGF-1 increased to the range of 219-233 ng/mL. Pre-operative serum IGF-1 levels were low probably due to poorly controlled diabetes mellitus. In conclusion, the presence of normal serum IGF-1 levels cannot exclude the diagnosis of acromegaly especially when the patient is accompanied by diabetes mellitus.

Relationships among magnetic resonance imaging, histological findings, and IGF-I in steroid-induced osteonecrosis of the femoral head in rabbits

OBJECTIVE

To study the relationships among magnetic resonance imaging (MRI), histological findings, and insulin-like growth factor-I (IGF-I) in steroid-induced osteonecrosis of the femoral head in rabbits.

METHODS

Thirty rabbits were randomly divided into experimental Group A (n=15) and control Group B (n=15). The 7.5 mg/kg (2 ml) of dexamethasone (DEX) and physiological saline (2 ml) were injected into the right gluteus medius muscle twice at one-week intervals in animals of Groups A and B, respectively. At 4, 8 and 16 weeks after obtaining an MRI, the rabbits were sacrificed and the femoral head from one side was removed for histological study of lacunae empty of osteocytes, subchondral vessels, and size of fat cells under microscopy, and the femoral head from the other side was removed for enzyme-linked immunoadsorbent assay (ELISA) for IGF-I.

RESULTS

At 4, 8 and 16 weeks after treatment, no necrotic lesions were detected in Group B, while they were detected in Group A. Light microscopy revealed that the fat cells of the marrow cavity were enlarged, subchondral vessels were evidently decreased, and empty bone lacunae were clearly increased. The IGF-I levels in Group A were significantly higher than those in Group B. At 8 weeks after the DEX injection, the MRI of all 20 femora showed an inhomogeneous, low signal intensity area in the femoral head, and at 16 weeks, the findings of all 10 femora showed a specific "line-like sign". The MRI findings of all femora in Group B were normal.

CONCLUSION

MRI is a highly sensitive means of diagnosing early experimental osteonecrosis of the femoral head. However, the abnormal marrow tissues appeared later than 4 weeks when the expression of IGF-I increased. This reparative factor has an early and important role in response to steroid-induced osteonecrosis of the femoral head, and provides a theoretical foundation for understanding the pathology and designing new therapies.

The impact of music on hypermetabolism in critical illness

PURPOSE OF REVIEW

Although the literature on complementary therapy, including music, is vast, there are few studies conducted in a scientific fashion exploring physiologic mechanisms. This review summarizes recent evidence on the effects of music on the hypermetabolic response of critical illness.

RECENT FINDINGS

Music may restore some of the distorted homeostasis observed in ICU patients, as well as reducing pain and the need for sedation. Music likely reduces alterations in the hypothalamic-anterior pituitary-peripheral hormone axes that produce cortisol and growth hormone. Music may also increase growth hormone levels, which can induce decreased production of cytokines such as IL-6 by white blood cells. Further, ovarian steroid secretion may paradoxically protect women by increasing baseline circulating stress hormones, providing an opportunity for music therapy to intervene effectively. Dopaminergic neurotransmission has been implicated as a means by which music can modulate the central nervous system.

SUMMARY

Music may play an important role as an adjunct therapy in critical care. However, further studies are necessary to elucidate how music can be further integrated clinically and the precise underlying mechanisms of its beneficial effects.

Frailty, osteoporosis and hip fracture: causes, consequences and therapeutic perspectives

OBJECTIVE

The aim of this review of the literature is to report the factors which both contribute to the frailty syndrome and increase hip fracture risk in the elderly. This work is the fruit of common reflection by geriatricians, endocrinologists, gynecologists and rheumatologists, and seeks to stress the importance of detection and management of the various components of frailty in elderly subjects who are followed and treated for osteoporosis. It also sets out to heighten awareness of the need for management of osteoporosis in the frail elderly.

DESIGN

The current literature on frailty and its links with hip fracture was reviewed and discussed by the group.

RESULTS

The factors and mechanisms which are common to both osteoporosis and frailty (falls, weight loss, sarcopenia, low physical activity, cognitive decline, depression, hormones such as testosterone, estrogens, insulin-like growth factor-I (IGF-I), growth hormone (GH), vitamin D and pro-inflammatory cytokines) were identified. The obstacles to access to diagnosis and treatment of osteoporosis in the frail elderly population and common therapeutic pathways for osteoporosis and frailty were discussed.

CONCLUSION

Future research including frail subjects would improve our understanding of how management of frailty can can contribute to lower the incidence of fractures. In parallel, more systematic management of osteoporosis should reduce the risk of becoming frail in the elderly population.

Infection, immunity, and hormones/endocrine interactions

Infections and stress, immune responses, and hormones are interconnected, ensuring immune competence to deal with immediate threat of overwhelming infection and metabolic collapse. Emergence of cytokines as key signal mediators and appreciation of autocrine-paracrine influences of hormones have helped explain how signals are transmitted and responses evoked. This has led to possibilities of creating therapies that might be used to enhance protective signals and dampen signals emanating from host and invading organism interaction that might otherwise be detrimental. Correcting certain metabolic abnormalities, such as hyperglycemia and metabolic acidosis, benefits the host by decreasing morbidity and mortality.

Systemic illness

Systemic illnesses are associated with alterations in the hypothalamic-pituitary-peripheral hormone axes, which represent part of the adaptive response to stressful events and may be influenced by type and severity of illness and/or pharmacological therapy. The pituitary gland responds to an acute stressful event with two secretory patterns: adrenocorticotropin (ACTH), prolactin (PRL) and growth hormone (GH) levels increase, while luteinizing hormone (LH), follicle-stimulating hormone (FSH) and thyrotropin (TSH) levels may either decrease or remain unchanged, associated with a decreased activity of their target organ. In protracted critical illness, there is a uniformly reduced pulsatile secretion of ACTH, TSH, LH, PRL and GH, causing a reduction in serum levels of the respective target-hormones. These adaptations are initially protective; however, if inadequate or excessive they may be dangerous and may contribute to the high morbidity and mortality risk of these patients. There is no consensus regarding the type of approach, as well as the criteria to use to define pituitary axis function in critically ill patients. We here provide a critical approach to pituitary axis evaluation during systemic illness.

Metabolism modulators in sepsis: the abnormal pituitary response

OBJECTIVE

Summarize the current knowledge on the role of the hypothalamic pituitary axis in the development of sepsis.

DESIGN

Review article.

METHOD

We systematically searched for relevant articles in MEDLINE and Embase (up to December 2006) using the following search terms: sepsis or septic shock or septicemia or endotoxemia and pituitary gland or hypothalamus. We also retrieved relevant references from selected articles.

RESULTS

During sepsis, the pituitary gland is activated via blood-borne proinflammatory cytokines and through a complex interaction between the autonomic nervous system and the immune cells. Sepsis elicits a very reproducible pattern of pituitary hormone secretion, with plasma adrenocorticotropin and prolactin increasing within a few minutes following the insult, and with a rapid inhibition of secretion of luteinizing and thyroid-stimulatory hormone but not of follicle-stimulating hormone. Growth hormone secretion also is stimulated. Nitric oxide is a key mediator in the activation of the hypothalamic-pituitary axis and in excess nitric oxide is the main factor accounting for abnormal pituitary response. Low adrenocorticotropin and vasopressin levels are likely the most deleterious consequences of the abnormal pituitary response, because they will contribute to shock and progression of inflammation with subsequent multiple organ failure and death.

CONCLUSIONS

Sepsis is associated with major changes in the hypothalamic-pituitary axis. The manipulation of the pituitary function during sepsis is a major challenge for the next decade.

Endocrine modifications and interventions during critical illness

The ongoing hypermetabolic response in patients with prolonged critical illness leads to the loss of lean tissue mass. Since the cachexia of prolonged illness is usually associated with low concentrations of anabolic hormones, hormonal intervention has been thought to be beneficial. However, most interventions have been shown to be ineffective and their indiscriminate use even causes harm. Before considering endocrine intervention in these frail patients, a detailed understanding of the neuroendocrinology of the stress response is warranted. It is now clear that the acute phase and the later phase of critical illness behave differently from an endocrinological point of view. The acute stress reponse consists primarily of an actively-secreting pituitary in the presence of low circulating peripheral anabolic hormones, suggesting resistance of the peripheral tissues to the effects of anterior pituitary hormones. However, when the disease process becomes prolonged, there is a uniformly-reduced pulsatile secretion of anterior pituitary hormones with proportionally reduced concentrations of peripheral anabolic hormones. The origin of this suppressed pituitary secretion is located in the hypothalamus, as hypothalamic secretagogues can reactivate the anterior pituitary and restore pulsatile secretion. The reactivated pituitary secretion is accompanied by an increase in peripheral target hormones, indicating at least partial sensitivity of these tissues to anterior pituitary hormones in this chronic phase of illness. Thus, endocrine intervention with a combination of hypothalamic secretagogues that more completely reactivate the anterior pituitary could be a more physiological and effective strategy for inducing anabolism in patients with prolonged critical illness.

Thyroid function in children with sepsis and septic shock

AIM

A prospective study was conducted to determine thyroid hormone levels and their relationship to survival in children with septic shock and sepsis.

METHODS

We estimated thyroid hormone levels (T3, T4, TSH, fT3 and fT4) in children with septic shock and compared with those in children with sepsis.

RESULTS

Twenty-four children (13 boys) with septic shock and 25 children (14 boys) with sepsis were enrolled. The median T3, T4, fT3, fT4 and TSH (95% confidence interval) were 40 (40-40.23) ng/dL, 4.45 (1.9-6.03) microg/dL, 1.85 (1.2-2.37) pg/mL, 0.77 (0.57-0.95) ng/dL, 0.51 (0.26-1.15) microIU/mL, respectively in children with septic shock group compared with 130 (98.28-163.48) ng/dL, 9.3 (7.66-10.63) microg/dL, 3.2 (3-4.27) pg/mL, 1.3 (1.1-1.4) ng/dL, 2.85 (1.07-3.61) microIU/mL, respectively, in children with sepsis. Children with septic shock who died (n = 12) had higher TSH levels compared to those who survived (p = 0.04). There was no difference in hormone levels between children with catecholamine responsive and catecholamine resistant septic shock.

CONCLUSION

Children with septic shock had lower levels of T3, T4, fT3, fT4 and TSH compared to those with sepsis. Findings of our study suggest that derangement of thyroid functions in children is not an important factor contributing to the severity of septic shock.

Parenteral versus enteral nutrition: effect on serum cytokines and the hepatic expression of mRNA of suppressor of cytokine signaling proteins, insulin-like growth factor-1 and the growth hormone receptor in rodent sepsis

INTRODUCTION

Early nutrition is recommended for patients with sepsis, but data are conflicting regarding the optimum route of delivery. Enteral nutrition (EN), compared with parenteral nutrition (PN), results in poorer achievement of nutritional goals but may be associated with fewer infections. Mechanisms underlying differential effects of the feeding route on patient outcomes are not understood, but probably involve the immune system and the anabolic response to nutrients. We studied the effect of nutrition and the route of delivery of nutrition on cytokine profiles, the growth hormone-insulin-like growth factor-1 (IGF-I) axis and a potential mechanism for immune and anabolic system interaction, the suppressors of cytokine signaling (SOCS), in rodents with and without sepsis.

METHODS

Male Sprague-Dawley rats were randomized to laparotomy (Sham) or to cecal ligation and puncture (CLP), with postoperative saline infusion (Starve), with EN or with PN for 72 hours. Serum levels of IL-6 and IL-10 were measured by immunoassay, and hepatic expressions of cytokine-inducible SH2-containing protein, SOCS-2, SOCS-3, IGF-I and the growth hormone receptor (GHR) were measured by real-time quantitative PCR.

RESULTS

IL-6 was detectable in all groups, but was only present in all animals receiving CLP-PN. IL-10 was detectable in all but one CLP-PN rat, one CLP-EN rat, approximately 50% of the CLP-Starve rats and no sham-operated rats. Cytokine-inducible SH2-containing protein mRNA was increased in the CLP-EN group compared with the Sham-EN group and the other CLP groups (P < 0.05). SOCS-2 mRNA was decreased in CLP-PN rats compared with Sham-PN rats (P = 0.07). SOCS-3 mRNA was increased with CLP compared with sham operation (P < 0.03). IGF-I mRNA (P < 0.05) and GHR mRNA (P < 0.03) were greater in the fed CLP animals and in the Sham-PN group compared with the starved rats.

CONCLUSION

In established sepsis, nutrition and the route of administration of nutrition influences the circulating cytokine patterns and expression of mRNA of SOCS proteins, GHR and IGF-I. The choice of the administration route of nutrition may influence cellular mechanisms that govern the response to hormones and mediators, which further influence the response to nutrients. These findings may be important in the design and analysis of clinical trials of nutritional interventions in sepsis in man.

The inflammatory response to surgery and trauma

PURPOSE OF REVIEW

The inflammatory or stress response to injury has evolved to ensure survival. This review will examine this response in otherwise healthy patients. Additionally, the impact of several common comorbid conditions on the inflammatory response will be considered. What will become evident is that the stress response may be exaggerated in some conditions and suppressed in others. Rapid identification of both an abnormal response and its cause will allow clinicians to maximize a patient's healing potential.

RECENT FINDINGS

Recent work has shown that an altered inflammatory response has marked effects on both immune competence and the endocrine system. Investigations are ongoing to delineate the mechanism of lymphocyte dysfunction. With regard to critical care endocrinopathies, the effects of insulin and hyperglycemia on inflammation and wound healing are being investigated.

SUMMARY

An understanding of the stress response will aid the clinician in preparing for expected responses, recognizing and perhaps correcting deviations from the norm and accounting for potential complications that arise in the face of preexisting disease. Deviations from the normal time course may represent the effects of preexisting medical illness, treatment or postoperative/injury complications.

The dynamic neuroendocrine response to critical illness

The severity of striking alterations in the hypothalamic-anterior pituitary-peripheral hormone axes, which are the hallmark of severity of critical illness, is associated with a high risk for morbidity and mortality. Most attempts to correct the hormone balance are ineffective or harmful because of lack of pathophysiologic understanding. Extensive research has provided more insight in the biphasic neuroendocrine response to critical illness: the acute phase is characterized by an actively secreting pituitary but low peripheral effector hormone levels. In contrast, in prolonged critical illness, uniform suppression of the neuroendocrine axes, predominantly of hypothalamic origin, contributes to low serum levels of the respective target-organ hormones.

Changes within the growth hormone/insulin-like growth factor I/IGF binding protein axis during critical illness

Interest in the somatotropic axis,with its complex network of interactions, during critical illness arose only a few decades ago. Te distinguishing neuroendocrine features of prolonged critical illness were not differentiated from those during the acute phase until the early 1990s. This incomplete understanding of the somatotropic axis contributed to some disastrous results, such as the multicenter growth hormone trial. The goal of stimulating the somatotropic axis without a proper preceding neuroendocrine diagnosis should be held obsolete. Moreover, the fascinating link between regulators of carbohydrate metabolism, such as insulin and insulin-like growth factor I, and the somatotropic axis may lead to future therapeutic possibilities.