Growth hormone and insulin-like growth factor 1 levels and their relation to survival in children with bacterial sepsis and septic shock

CLINICAL, MOLECULAR, AND EXOSOMAL MECHANISMS OF CARDIAC AND BRAIN DYSFUNCTION IN SEPSIS

ABSTRACT

Sepsis is a complex disease resulting from a dysregulated inflammatory response to an infection. Initiation of sepsis occurs from a localized infection that disseminates to the bloodstream placing all organ systems at risk. Septic shock is classically observed to manifest itself as systemic hypotension with hyporesponsiveness to vasopressor agents. Myocardial dysfunction occurs resulting in an inability to perfuse major organ systems throughout the body. Most importantly, the brain is hypoperfused creating an ischemic and inflammatory state resulting in the clinical observation of acute mental status changes and cognitive dysfunction commonly known as sepsis-associated encephalopathy. This short review describes the inflammatory molecular mechanisms of myocardial dysfunction, discusses the evidence of the dual roles of the microglia resulting in blood-brain barrier disruption, and suggests that septic-derived exosomes, endosome-derived lipid bilayer spheroids released from living cells, influence cardiac and neurological cellular function.

Low Growth Hormone Levels Predict Poor Outcome of Hepatitis B Virus-Related Acute-on-Chronic Liver Failure

Background and Aims: Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) remains a serious entity with high mortality. Growth hormone (GH) is related to the liver metabolism and regeneration. The present study aimed to explore the changes and prognostic efficacy of GH on the outcome of HBV-ACLF.

Methods: A prospective cohort of 124 patients and a cross-sectional cohort of 142 subjects were enrolled. GH and insulin-like growth factor-1(IGF-1) were detected by ELISA. Thirty-day survival was collected and the association between GH and the 30-day mortality of HBV-ACLF was analyzed.

Results: The mean age of the whole prospective cohort was 46.61 ± 12.71 years, and 19 (15.3%) patients were female. The median (IQR) of GH levels in non-survivors were 1106.55 (674.25, 1922.4) pg/ml, which were significantly lower than in survivors (p < 0.001). In the cross-sectional cohort, GH level was significantly higher in liver cirrhosis - acute decompensation (LC-AD) group than liver cirrhosis (LC) group (p < 0.001) while IGF-1 decreased significantly in LC, LC-AD, ACLF groups than health control (HC) and chronic Hepatitis B (CHB) groups (p < 0.001). The area under the receiver operating characteristic curve (AUROC) of GH for predicting 30-day mortality was 0.793. We built a new prognostic model, namely MELD-GH, which showed better predictive efficacy than Child-Pugh, MELD, CLIF-SOFA, and CLIF-C ACLF scores.

Conclusions: Low GH predicted the poor outcome of HBV-ACLF patients. GH and IGF-1 levels were differently distributed among HC, CHB, LC, LC-AD, and ACLF patients. MELD-GH had better predictive accuracy when compared to Child-Pugh, MELD, CLIF-SOFA, and CLIF-C ACLF scores.

Sepsis as a Pan-Endocrine Illness-Endocrine Disorders in Septic Patients

Sepsis is defined as "life-threatening organ dysfunction caused by a dysregulated host response to infection". One of the elements of dysregulated host response is an endocrine system disorder. Changes in its functioning in the course of sepsis affect almost all hormonal axes. In sepsis, a function disturbance of the hypothalamic-pituitary-adrenal axis has been described, in the range of which the most important seems to be hypercortisolemia in the acute phase. Imbalance in the hypothalamic-pituitary-thyroid axis is also described. The most typical manifestation is a triiodothyronine concentration decrease and reverse triiodothyronine concentration increase. In the somatotropic axis, a change in the secretion pattern of growth hormone and peripheral resistance to this hormone has been described. In the hypothalamic-pituitary-gonadal axis, the reduction in testosterone concentration in men and the stress-induced "hypothalamic amenorrhea" in women have been described. Catecholamine and β-adrenergic stimulation disorders have also been reported. Disorders in the endocrine system are part of the "dysregulated host response to infection". They may also affect other components of this dysregulated response, such as metabolism. Hormonal changes occurring in the course of sepsis require further research, not only in order to explore their potential significance in therapy, but also due to their promising prognostic value.

Role of ghrelin on growth hormone/insulin-like growth factor-1 axis during endotoxemia

OBJECTIVE

To investigate the anti-inflammatory property of ghrelin treatment on the Growth Hormone (GH)/Insulin-like Growth Factor-I (IGF-1) axis in Wistar rats that have undergone endotoxemia.

DESIGN

In this randomized animal study, lipopolysaccharide (LPS) (5 mg/kg; intraperitoneal) was administered to induce endotoxemia, and ghrelin (15 nmol/kg; endovenous) was injected simultaneously. Blood and liver samples were collected 2 h, 6 h and 12 h after LPS administration for analysis.

MEASUREMENTS

Tumor necrosis factor alpha (TNF-α), interleukin (IL)-1, beta (IL-1β), and IL-6 from both blood and liver were determined by ELISA assay. Serum nitrate was determined by chemiluminescense. Growth hormone receptor (GHR) and growth hormone secretagogue receptor 1a (GHSR-1a) were determined by western blotting. GHR mRNA and IGF-1 mRNA were determined by RT-PCR.

RESULTS

LPS administration induced a decrease in IGF-1 and GH serum levels, characterizing GH/IGF-1 axis disruption. Ghrelin treatment attenuated the decrease of serum levels of IGF-1 as well as the increase of TNF-α, IL-1β, IL-6 and nitrate induced by LPS. The increase of induced GHSR-1a protein expression seen in the LPS group after 2 h remained until 6 h after ghrelin treatment. However, attenuation of the circulating IGF-1 decrease by ghrelin treatment was not accompanied by changes in GHR protein expression nor GHR and IGF-1 gene expression.

CONCLUSION

Ghrelin was able to attenuate changes in the GH/IGF-1 axis observed during systemic inflammation, which may be due to the modulation of pro-inflammatory mediators release.

Global Case-Fatality Rates in Pediatric Severe Sepsis and Septic Shock: A Systematic Review and Meta-analysis

IMPORTANCE

The global patterns and distribution of case-fatality rates (CFRs) in pediatric severe sepsis and septic shock remain poorly described.

OBJECTIVE

We performed a systematic review and meta-analysis of studies of children with severe sepsis and septic shock to elucidate the patterns of CFRs in developing and developed countries over time. We also described factors associated with CFRs.

DATA SOURCES

We searched PubMed, Web of Science, Excerpta Medica database, Cumulative Index of Nursing and Allied Health Literature (CINAHL), and Cochrane Central systematically for randomized clinical trials and prospective observational studies from earliest publication until January 2017, using the keywords "pediatric," "sepsis," "septic shock," and "mortality."

STUDY SELECTION

Studies involving children with severe sepsis and septic shock that reported CFRs were included. Retrospective studies and studies including only neonates were excluded.

DATA EXTRACTION AND SYNTHESIS

We conducted our systematic review and meta-analysis in close accordance to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled case-fatality estimates were obtained using random-effects meta-analysis. The associations of study period, study design, sepsis severity, age, and continents in which studies occurred were assessed with meta-regression.

MAIN OUTCOMES AND MEASURES

Meta-analyses to provide pooled estimates of CFR of pediatric severe sepsis and septic shock over time.

RESULTS

Ninety-four studies that included 7561 patients were included. Pooled CFRs were higher in developing countries (31.7% [95% CI, 27.3%-36.4%]) than in developed countries (19.3% [95% CI, 16.4%-22.7%]; P < .001). Meta-analysis of CFRs also showed significant heterogeneity across studies. Continents that include mainly developing countries reported higher CFRs (adjusted odds ratios: Africa, 7.89 [95% CI, 6.02-10.32]; P < .001; Asia, 3.81 [95% CI, 3.60-4.03]; P < .001; South America, 2.91 [95% CI, 2.71-3.12]; P < .001) than North America. Septic shock was associated with higher CFRs than severe sepsis (adjusted odds ratios, 1.47 [95% CI, 1.41-1.54]). Younger age was also a risk factor (adjusted odds ratio, 0.95 [95% CI, 0.94-0.96] per year of increase in age). Earlier study eras were associated with higher CFRs (adjusted odds ratios for 1991-2000, 1.24 [95% CI, 1.13-1.37]; P < .001) compared with 2011 to 2016. Time-trend analysis showed higher CFRs over time in developing countries than developed countries.

CONCLUSIONS AND RELEVANCE

Despite the declining trend of pediatric severe sepsis and septic shock CFRs, the disparity between developing and developed countries persists. Further characterizations of vulnerable populations and collaborations between developed and developing countries are warranted to reduce the burden of pediatric sepsis globally.

Endocrine and Local IGF-I in the Bony Fish Immune System

A role for GH and IGF-I in the modulation of the immune system has been under discussion for decades. Generally, GH is considered a stimulator of innate immune parameters in mammals and teleost fish. The stimulatory effects in humans as well as in bony fish often appear to be correlated with elevated endocrine IGF-I (liver-derived), which has also been shown to be suppressed during infection in some studies. Nevertheless, data are still fragmentary. Some studies point to an important role of GH and IGF-I particularly during immune organ development and constitution. Even less is known about the potential relevance of local (autocrine/paracrine) IGF-I within adult and developing immune organs, and the distinct localization of IGF-I in immune cells and tissues of mammals and fish has not been systematically defined. Thus far, IGF-I has been localized in different mammalian immune cell types, particularly macrophages and granulocytes, and in supporting cells, but not in T-lymphocytes. In the present study, we detected IGF-I in phagocytic cells isolated from rainbow trout head kidney and, in contrast to some findings in mammals, in T-cells of a channel catfish cell line. Thus, although numerous analogies among mammals and teleosts exist not only for the GH/IGF-system, but also for the immune system, there are differences that should be further investigated. For instance, it is unclear whether the primarily reported role of GH/IGF-I in the innate immune response is due to the lack of studies focusing on the adaptive immune system, or whether it truly preferentially concerns innate immune parameters. Infectious challenges in combination with GH/IGF-I manipulations are another important topic that has not been sufficiently addressed to date, particularly with respect to developmental and environmental influences on fish growth and health.

Developmental oestrogen exposure differentially modulates IGF-I and TNF-α expression levels in immune organs of Yersinia ruckeri-challenged young adult rainbow trout (Oncorhynchus mykiss)

Intensified aquaculture has strong impact on fish health by stress and infectious diseases and has stimulated the interest in the orchestration of cytokines and growth factors, particularly their influence by environmental factors, however, only scarce data are available on the GH/IGF-system, central physiological system for development and tissue shaping. Most recently, the capability of the host to cope with tissue damage has been postulated as critical for survival. Thus, the present study assessed the combined impacts of estrogens and bacterial infection on the insulin-like growth factors (IGF) and tumor-necrosis factor (TNF)-α. Juvenile rainbow trout were exposed to 2 different concentrations of 17β-estradiol (E2) and infected with Yersinia ruckeri. Gene expressions of IGF-I, IGF-II and TNF-α were measured in liver, head kidney and spleen and all 4 estrogen receptors (ERα1, ERα2, ERβ1 and ERβ2) known in rainbow trout were measured in liver. After 5 weeks of E2 treatment, hepatic up-regulation of ERα1 and ERα2, but down-regulation of ERß1 and ERß2 were observed in those groups receiving E2-enriched food. In liver, the results further indicate a suppressive effect of Yersinia-infection regardless of E2-treatment on day 3, but not of E2-treatment on IGF-I whilst TNF-α gene expression was not influenced by Yersinia-infection but was reduced after 5 weeks of E2-treatment. In spleen, the results show a stimulatory effect of Yersinia-infection, but not of E2-treatment on both, IGF-I and TNF-α gene expressions. In head kidney, E2 strongly suppressed both, IGF-I and TNF-α. To summarise, the treatment effects were tissue- and treatment-specific and point to a relevant role of IGF-I in infection.

Somatotropic axis resistance and ghrelin in critically ill foals

REASONS FOR PERFORMING STUDY

Resistance to the somatotropic axis and increases in ghrelin concentrations have been documented in critically ill human patients, but limited information exists in healthy or sick foals.

OBJECTIVES

To investigate components of the somatotropic axis (ghrelin, growth hormone and insulin-like growth factor-1 [IGF-1]) with regard to energy metabolism (glucose and triglycerides), severity of disease and survival in critically ill equine neonates. It was hypothesised that ghrelin and growth hormone would increase and IGF-1 would decrease in proportion to severity of disease, supporting somatotropic axis resistance, which would be associated with severity of disease and mortality in sick foals.

STUDY DESIGN

Prospective multicentre cross-sectional study.

METHODS

Blood samples were collected at admission from 44 septic, 62 sick nonseptic (SNS) and 19 healthy foals, all aged <7 days. Foals with positive blood cultures or sepsis scores ≥12 were considered septic, foals with sepsis scores of 5-11 were classified as SNS. Data were analysed by nonparametric methods and multivariate logistic regression.

RESULTS

Septic foals had higher ghrelin, growth hormone and triglyceride and lower IGF-1 and glucose concentrations than healthy foals (P<0.01). Sick nonseptic foals had higher growth hormone and triglycerides and lower IGF-1 concentrations than healthy foals (P<0.05). Growth hormone:IGF-1 ratio was higher in septic and SNS foals than healthy foals (P<0.05). Hormone concentrations were not different between septic nonsurvivors (n = 14) and survivors (n = 30), but the growth hormone:IGF-1 ratio was lower in nonsurvivors (P = 0.043).

CONCLUSIONS

Somatotropic axis resistance, characterised by a high growth hormone:IGF-1 ratio, was frequent in sick foals, associated with the energy status (hypoglycaemia, hypertriglyceridaemia) and with mortality in septic foals.

POTENTIAL RELEVANCE

A functional somatotropic axis appears to be important for foal survival during sepsis. Somatotropic resistance is likely to contribute to severity of disease, a catabolic state and likelihood of recovery.

Common endocrine issues in the pediatric intensive care unit

Thyroid hormone is central to normal development and metabolism. Abnormalities in thyroid function in North America often arise from autoimmune diseases, but they rarely present as critical illness. Severe deficiency or excess of thyroid hormone both represent life-threatening disease, which must be treated expeditiously and thoroughly. Such deficiencies must be considered, because presentation may be nonspecific.

Growth hormone (GH) treatment acts on the endocrine and autocrine/paracrine GH/IGF-axis and on TNF-α expression in bony fish pituitary and immune organs

There exist indications that the growth hormone (GH)/insulin-like growth factor (IGF) axis may play a role in fish immune regulation, and that interactions occur via tumour necrosis factor (TNF)-α at least in mammals, but no systematic data exist on potential changes in GH, IGF-I, IGF-II, GH receptor (GHR) and TNF-α expression after GH treatment. Thus, we investigated in the Nile tilapia the influence of GH injections by real-time qPCR at different levels of the GH/IGF-axis (brain, pituitary, peripheral organs) with special emphasis on the immune organs head kidney and spleen. Endocrine IGF-I served as positive control for GH treatment efficiency. Basal TNF-α gene expression was detected in all organs investigated with the expression being most pronounced in brain. Two consecutive intraperitoneal injections of bream GH elevated liver IGF-I mRNA and plasma IGF-I concentration. Also liver IGF-II mRNA and TNF-α were increased while the GHR was downregulated. In brain, no change occurred in the expression levels of all genes investigated. GH gene expression was exclusively detected in the pituitary where the GH injections elevated both GH and IGF-I gene expression. In the head kidney, GH upregulated IGF-I mRNA to an even higher extent than liver IGF-I while IGF-II and GHR gene expressions were not affected. Also in the spleen, no change occurred in GHR mRNA, however, IGF-I and IGF-II mRNAs were increased. In correlation, in situ hybridisation showed a markedly higher amount of IGF-I mRNA in head kidney and spleen after GH injection. In both immune tissues, TNF-α gene expression showed a trend to decrease after GH treatment. The stimulation of IGF-I and also partially of IGF-II expression in the fish immune organs by GH indicates a local role of the IGFs in immune organ regulation while the differential changes in TNF-α support the in mammals postulated interactions with the GH/IGF-axis which demand for further investigations.

Endocrine dysregulation in critically ill foals and horses

Critical illness challenges many endocrine homeostatic systems to overcome diseases, stress, and hostile conditions that threaten survival. Coordinated and consecutive responses by the autonomic nervous system, endocrine metabolic adaptations to mobilize and conserve energy and electrolytes, cardiovascular adjustments to maintain organ perfusion, and immunomodulation to overcome infections and inflammation are required. Because most admissions to equine intensive care units are related to horses with gastrointestinal disease and septic foals, most endocrine information during critical disease are generated from these populations. This article presents an overview on endocrine responses to critical illness in horses and foals and also some comparative information.

Initial observations regarding free cortisol quantification logistics among critically ill children

PURPOSE

Corticosteroid insufficiency may occur among critically ill patients, but the diagnosis remains controversial. Historically assessment of free cortisol (FC) by means of equilibrium dialysis (ED) has required large blood volumes and prolonged fractionation time preceding analysis. We hypothesized that temperature-controlled centrifugal ultrafiltration with chemiluminescence immunoassay (CU/CI) would provide real-time FC data that highly correlated with ED/radioimmunoassay (ED/RI) or liquid chromatography/mass spectrometry (LC/MS) techniques.

METHODS

We quantified and correlated baseline and corticotropin-stimulated TC and FC by means of CU/CI, ED/RI, and LC/MS among healthy adults and 37 critically ill children.

RESULTS

Among critically ill children, FC was three- to fivefold higher than the healthy adults at baseline and increased another five- to eightfold following corticotropin administration. While TC increased approximately twofold following corticotropin administration, FC increased on average more than eightfold. Serum FC per CU/CI highly correlated with FC per ED/RI or LC/MS, but results were available in a fraction of the time. Children failing to increase TC by >9.0 μg/dL (248 nM) following corticotropin demonstrated an appropriate FC increase. Nearly 50% of critically ill children exhibited FC <2.0 μg/dL (55 nM). Neither FC nor TC concentrations correlated significantly with measures of illness severity.

CONCLUSIONS

Quantification of FC utilizing CU/CI was fast (1-2 h) and results correlated highly with ED/RI or LC/MS methodologies. These data require validation with larger cohorts of healthy and critically ill children but indicate that real-time FC quantification is available to guide cortisol replacement therapy.

Failure to recover somatotropic axis function is associated with mortality from pediatric sepsis-induced multiple organ dysfunction syndrome

OBJECTIVES

To describe the associations between mediators of the somatotropic axis and mortality from sepsis-induced multiple organ dysfunction syndrome in children; and to examine the relationship between immune function and the somatotropic axis in this setting.

DESIGN

Retrospective study using banked plasma.

SETTING

Single mixed surgical/medical intensive care unit at a quaternary level children's hospital.

PATIENTS

A total of 24 children (n = 17 survivors, 7 nonsurvivors) with severe sepsis or septic shock and dysfunction of >or=2 organ systems.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Plasma samples were available from days 3, 7, and 14 of multiple organ dysfunction syndrome. Insulin-like growth factor 1 and insulin-like growth factor binding protein 3 levels were measured by chemiluminescence. Immune function was quantified using previously determined ex vivo lipopolysaccharide-induced tumor necrosis factor-alpha production levels and absolute lymphocyte counts. Insulin-like growth factor 1 levels were lower in nonsurvivors compared with survivors (p = .004) with the greatest difference seen on day 14 (25 [25-69] ng/mL vs. 314 [123-582] ng/mL; p = .038). insulin-like growth factor binding protein 3 levels were reduced similarly over time (p = .019). A drop in plasma insulin-like growth factor binding protein 3 level at any time after day 3 of illness resulted in a 35-fold increased odds of death (odds ratio, 35 [1.6-750]; p = .004). Both ex vivo tumor necrosis factor-alpha and absolute lymphocyte count were reduced in nonsurvivors compared with survivors, but these differences occurred earlier (days 3 and 7).

CONCLUSIONS

These data suggest that prolonged reduction of somatotropic axis function is associated with mortality from pediatric sepsis-induced multiple organ dysfunction syndrome. Reductions in innate and adaptive immune function are common in this population and are associated with failure of recovery of the somatotropic axis, although the nature of these relationships remains incompletely understood.

Expression, regulation and biological actions of growth hormone (GH) and ghrelin in the immune system

Immune and neuroendocrine systems have bidirectional communications. Growth hormone (GH) and an orexigenic hormone ghrelin are expressed in various immune cells such as T lymphocytes, B lymphocytes, monocytes and neutrophils. These immune cells also bear receptors for hormones: growth hormone receptor (GHR) for GH and growth hormone secretagogue receptor (GHS-R) for ghrelin. The expression of GH in immune cells is stimulated by ghrelin as in anterior pituitary cells, whereas the regulation of GH secretion in the immune system by other peptides seems to be different from that in the anterior pituitary gland. Cytokines and mitogens enhance GH secretion from immune cells. GH has several biological actions in the immune system: enhancing thymopoiesis and T cell development, modulating cytokine production, enhancing B cell development and antibody production, priming neutrophils and monocytes for superoxide anion secretion, enhancing neutrophil adhesion and monocyte migration and anti-apoptotic action. Biological actions of ghrelin include attenuation of septic shock and anti-inflammatory actions, modulating phagocytosis, and enhancing thymopoiesis. The effect of ghrelin may be direct or through GH production, and that of GH may be direct or through insulin like growth factor-I (IGF-I) production. Elucidation of the roles of GH and ghrelin in the immune system may shed light on the treatment and prevention of immunological disorders such as AIDS and organ damages due to obesity/ageing-related chronic inflammation.

Clinical practice parameters for hemodynamic support of pediatric and neonatal septic shock: 2007 update from the American College of Critical Care Medicine

BACKGROUND

The Institute of Medicine calls for the use of clinical guidelines and practice parameters to promote "best practices" and to improve patient outcomes.

OBJECTIVE

2007 update of the 2002 American College of Critical Care Medicine Clinical Guidelines for Hemodynamic Support of Neonates and Children with Septic Shock.

PARTICIPANTS

Society of Critical Care Medicine members with special interest in neonatal and pediatric septic shock were identified from general solicitation at the Society of Critical Care Medicine Educational and Scientific Symposia (2001-2006).

METHODS

The Pubmed/MEDLINE literature database (1966-2006) was searched using the keywords and phrases: sepsis, septicemia, septic shock, endotoxemia, persistent pulmonary hypertension, nitric oxide, extracorporeal membrane oxygenation (ECMO), and American College of Critical Care Medicine guidelines. Best practice centers that reported best outcomes were identified and their practices examined as models of care. Using a modified Delphi method, 30 experts graded new literature. Over 30 additional experts then reviewed the updated recommendations. The document was subsequently modified until there was greater than 90% expert consensus.

RESULTS

The 2002 guidelines were widely disseminated, translated into Spanish and Portuguese, and incorporated into Society of Critical Care Medicine and AHA sanctioned recommendations. Centers that implemented the 2002 guidelines reported best practice outcomes (hospital mortality 1%-3% in previously healthy, and 7%-10% in chronically ill children). Early use of 2002 guidelines was associated with improved outcome in the community hospital emergency department (number needed to treat = 3.3) and tertiary pediatric intensive care setting (number needed to treat = 3.6); every hour that went by without guideline adherence was associated with a 1.4-fold increased mortality risk. The updated 2007 guidelines continue to recognize an increased likelihood that children with septic shock, compared with adults, require 1) proportionally larger quantities of fluid, 2) inotrope and vasodilator therapies, 3) hydrocortisone for absolute adrenal insufficiency, and 4) ECMO for refractory shock. The major new recommendation in the 2007 update is earlier use of inotrope support through peripheral access until central access is attained.

CONCLUSION

The 2007 update continues to emphasize early use of age-specific therapies to attain time-sensitive goals, specifically recommending 1) first hour fluid resuscitation and inotrope therapy directed to goals of threshold heart rates, normal blood pressure, and capillary refill 70% and cardiac index 3.3-6.0 L/min/m.

Endotoxin-induced proteolytic reduction in hepatic growth hormone (GH) receptor: a novel mechanism for GH insensitivity

GH is an important anabolic hormone. We previously demonstrated in cell culture that the cell surface GH receptor (GHR) is susceptible to inducible metalloproteolytic cleavage that yields the shed receptor extracellular domain (called GH binding protein) and renders the cells desensitized to subsequent GH stimulation. Sepsis and inflammatory states are associated with hepatic desensitization to GH, although disparate mechanisms have been postulated in various animal models. Using C3H/HeJ mice, we now demonstrate that administration of lipopolysaccharide (LPS) causes marked hepatic desensitization to GH, assessed by monitoring signal transducer and activator of transcription 5 tyrosine phosphorylation and nuclear accumulation and with a novel noninvasive bioluminescence imaging system to track in vivo hepatic GH signaling serially in individual mice. This endotoxin-induced desensitization was accompanied by marked loss of hepatic GHR, which was not explained by changes in GHR mRNA abundance. Furthermore, we observe that LPS causes GH-binding protein shedding of a hepatically expressed wild-type GHR but not a GHR with a mutation in the metalloprotease cleavage site. These data suggest that in this model system, LPS-induced desensitization to GH is associated with proteolytic GHR cleavage. These data are the first to demonstrate inducible in vivo GHR proteolysis and suggest this is a mechanism to regulate GH sensitivity and its anabolic effects during sepsis or inflammation.

A history of adjunctive glucocorticoid treatment for pediatric sepsis: moving beyond steroid pulp fiction toward evidence-based medicine

OBJECTIVES

To review the history of clinical use of corticosteroids with particular reference to adjunctive therapy for severe pediatric sepsis and, in this context, to provide an overview of what is known, what is not known, and what research questions are particularly relevant at this time.

DATA SOURCE

Literature review using PubMed, cross-referenced article citations, and the Internet.

CONCLUSIONS

The history of corticosteroid use in clinical medicine has been colorful, noisy, and always controversial. Therapeutic corticosteroid indications that initially seemed rational have frequently been refuted on closer, rigorous clinical trial inspection. Although it may be prudent to provide stress-dose steroids to children with septic shock who are clinically at risk for adrenal insufficiency (chronic or recent steroid use, purpura fulminans, etomidate or ketoconazole administration, hypothalamic, pituitary, adrenal disease), the safety and efficacy of stress-dose steroids as general adjunctive therapy for pediatric septic shock have not been established. Glucocorticoid administration does add potential risk to critically ill children. In particular, although adjunctive corticosteroids may hasten resolution of unstable hemodynamics in septic shock, this may occur at the metabolic cost of hyperglycemia. Clinical practice that fosters innovative therapy (off-label use) over research probably represents bad medical and social policy. Accordingly, pediatric critical care researchers have a responsibility to generate pediatric-specific evidence-based medicine for adjunctive corticosteroid therapy for severe sepsis in children.

Differential influence of open surgery and sepsis on the circulating insulin-like growth factors and their binding proteins as representative metabolic markers

OBJECTIVES

In critical illnesses and stress conditions many endocrine systems are disturbed. In the current study we determined the influence of open surgery, post-operative sepsis and its early therapy on the components of the insulin-like growth factor (IGF) system in patients with malignant gastric or pancreatic tumors.

DESIGN AND METHODS

Twenty-one patients and eighty-one age- and sex-matched healthy subjects were included in this study. IGF-I, IGF-II, IGF binding proteins (IGFBPs), cortisol, insulin and protein concentrations (total, albumin and IgG) were determined pre-operatively, post-operatively, when sepsis was diagnosed and 48 h after initiating therapy.

RESULTS

The concentrations of circulating IGF-I, IGF-II and IGFBP-3 were significantly lower in pre-operative patients compared to healthy subjects. Sepsis caused a further decrease in IGF-I and IGFBP-3 but an increase in IGFBP-1, IGFBP-2 and IGFBP-4 resulting in a redistribution of IGF molecules from ternary to binary complexes.

CONCLUSIONS

The presence of malignant gastric or pancreatic tumors followed by post-operative sepsis caused a serious misbalance in components of the IGF system which failed to recover during the time of our longitudinal study.

Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats

The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax protein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 +/- 0.24; T3d: 2.14 +/- 0.48 microg/L vs S1d: 0.74 +/- 0.12; S3d: 0.60 +/- 0.18 microg/L; P < 0.05) and IGF-1 (T1d: 168.94 +/- 65.67; T3d: 201.56 +/- 64.98 microg/L vs S1d: 116.72 +/- 13.96; S3d: 107.50 +/- 23.53 microg/L; P < 0.05) and expression of liver IGF-1 mRNA (T1d: 0.98 +/- 0.20; T3d: 1.76 +/- 0.17 vs S1d: 0.38 +/- 0.09; S3d: 0.46 +/- 0.10; P < 0.05). These findings indicate that treatment with rhGH had beneficial effects on the maintenance of the integrity of the intestinal mucosa barrier in septic rats.