Serum Levels of Prolactin, Growth Hormone, and Cortisol in Burn Patients: Correlations with Severity of Burn, Serum Cytokine Levels, and Fatality

Postmortem study of adrenomedullin and cortisol in femoral serum and pericardial fluid related to acute pulmonary edema

Currently, various tools aid in determining the cause of death and the circumstances surrounding it. Thanatochemistry is one such method that provides insights into the physiopathological mechanisms of death and the behavior of specific biomarkers in different body fluids postmortem. Certain biomarkers, characterized by their stability and specificity to vital tissues like the lungs, are associated with mechanisms contributing to death, such as acute pulmonary edema (APE). This study aims to analyze the behavior of midregional pro-adrenomedullin (MR-proADM) and cortisol levels, measured in pericardial fluid and femoral serum, in relation to the severity of APE, categorized according to specific criteria. Samples were collected from a total of 92 corpses (77 males, 15 females) with a mean age of 56.7 ± 15.2 years. The severity of APE associated with the deaths was classified into three groups: slight or absent (n = 7; 8.6%), medium or moderate (n = 16; 19.8%), and intense (n = 58;71.6%).The determination of MR-proADM and cortisol levels was conducted using ELISA kits and an Immunoassay Analyzer, respectively. Our results reveal a significant increase in MR-proADM concentration with the severity of APE. Furthermore, a correlation was established between cortisol and MR-proADM concentrations in both pericardial fluid and femoral serum samples. This indicates that the severity of APE influences the production of ADM, regardless of the specific underlying pathophysiological mechanisms. Cortisol values were also found to be higher in the intense APE group compared to the moderate group.This study contributes to our understanding of the relationship between MR-proADM and cortisol, and the severity of APE, shedding light on potential applications in postmortem investigations.

Prolactin receptor in regulation of neuronal excitability and channels

Prolactin (PRL) activates PRL receptor isoforms to exert regulation of specific neuronal circuitries, and to control numerous physiological and clinically-relevant functions including; maternal behavior, energy balance and food intake, stress and trauma responses, anxiety, neurogenesis, migraine and pain. PRL controls these critical functions by regulating receptor potential thresholds, neuronal excitability and/or neurotransmission efficiency. PRL also influences neuronal functions via activation of certain neurons, resulting in Ca(2+) influx and/or electrical firing with subsequent release of neurotransmitters. Although PRL was identified almost a century ago, very little specific information is known about how PRL regulates neuronal functions. Nevertheless, important initial steps have recently been made including the identification of PRL-induced transient signaling pathways in neurons and the modulation of neuronal transient receptor potential (TRP) and Ca(2+) -dependent K(+) channels by PRL. In this review, we summarize current knowledge and recent progress in understanding the regulation of neuronal excitability and channels by PRL.

The endocrine response to severe burn trauma

The endocrine system is frequently altered after a major burn trauma. Besides the endocrine response to stress characterized by hypercortisolism, several hypothalamus-hypophysis-target gland axes are rapidly perturbed within a few days. These alterations can persist in the long term and deserve an appropriate treatment. Disturbances in water clearance and glucidic metabolism are also common and need to be diagnosed and corrected to decrease morbidity in such patients. Bone and mineral metabolism is deeply compromised and requires correction of mineral abnormalities in order to improve symptoms and prevent bone loss. No large prospective and/or intervention trials are available to date to elaborate age-related, evidence-based recommendations to monitor and treat burn-related endocrine alterations.

Trimethoprim-induced hyperkalemia in burn patients treated with intravenous or oral trimethoprim sulfamethoxazole for methicillin-resistant Staphylococcus aureus and other infections: nature or nurture?

Trimethoprim is well known to cause rashes; however, what is not commonly known is that it causes sudden and profound hyperkalemia in 10 to 20% of treated patients. The uniqueness of burn patients begs the question whether changes known to occur in these patients might also increase this trimethoprim effect. After institutional review board approval, a retrospective study evaluated 224 patients with thermal injury who had been treated with trimethoprim sulfamethoxazole (TMP-SMX), 24 of whom had underlying renal impairment (creatinine clearances <50 ml/min) and were excluded, leaving 200 patients for analysis. Three definitions of drug-induced hyperkalemia were used: 1) a ≥ 1 mEq/L rise, 2) a >0.8 mEq rise in potassium in <24 hours warranting early discontinuation of TMP-SMX, and 3) "marked" hyperkalemia defined as serum potassium of ≥ 5.5 mEq/L within 48 hours. A potassium level before trimethoprim exposure (TxK) and after TxK were collected retrospectively. Demographic data were analyzed with Student's t-test and trimethoprim dose alone, demonstrating a significant difference. Analysis of 200 patients exposed to trimethoprim demonstrated an elevation of potassium (first definition) in 31 patients (15.5%), a rapid change in serum potassium in two patients (second definition), and marked hyperkalemia (>5.5 mEq/L) in 13 patients (6.5%). Hyperkalemia never occurred in 166 of 200 patients (82%; before TxK, 3.9 ± 0.4; after TxK, 4.3 ± 0.5 mEq/L). Change in serum potassium among patients with hyperkalemia was 4.0 ± 0.5 mEq/L before TxK and 5.3 ± 0.7 mEq/L after TxK. Twelve published hyperkalemia risk factors were reviewed in these 200 patients and only history of hypertension and need for intubation was more common in those with hyperkalemia. A nearly 20% incidence of hyperkalemia and 6% serious hyperkalemia in burn patients is consistent with reports in patients without burn injury. These data also suggest that the metabolic and hormonal changes associated with burn injury do not increase further the genetically predisposed hyperkalemia resulting from exposure to trimethoprim. These data suggest patients treated with TMP-SMX should have routine serum potassium monitoring before discharge.

Biomarkers in community-acquired pneumonia: a state-of-the-art review

Community-acquired pneumonia (CAP) exhibits mortality rates, between 20% and 50% in severe cases. Biomarkers are useful tools for searching for antibiotic therapy modifications and for CAP diagnosis, prognosis and follow-up treatment. This non-systematic state-of-the-art review presents the biological and clinical features of biomarkers in CAP patients, including procalcitonin, C-reactive protein, copeptin, pro-ANP (atrial natriuretic peptide), adrenomedullin, cortisol and D-dimers.

Lack of Th17 cell generation in patients with severe burn injuries

Immunodeficient patients with severe burn injuries are extremely susceptible to infection with Candida albicans. In addition to Th1 cells, IL-17-producing CD4(+) T cells (Th17 cells) have recently been described as an important effector cell in host anti-Candida resistance. In this study, therefore, we tried to induce Th17 cells in cultures of severely burned patient PBMC by stimulation with the C. albicans Ag (CAg). In the results, the biomarkers for Th17 cells (IL-17 production and intracellular expression of IL-17 and retinoic acid receptor-related orphan receptor γt) were not displayed by burn patient PBMC stimulated with CAg, whereas these biomarkers of Th17 cells were detected in cultures of healthy donor PBMC stimulated with CAg. Burn patient sera were shown to be inhibitory on CAg-stimulated Th17 cell generation in healthy donor PBMC cultures; however, Th17 cells were induced by CAg in healthy donor PBMC cultures supplemented with burn patient sera that were previously treated with anti-IL-10 mAb. Also, the biomarkers of Th17 cells were not induced by CAg in healthy donor PBMC cultures supplemented with rIL-10. IL-10 was detected in serum specimens derived from severely burned patients. These results indicate that Th17 cells are not generated in burn patient PBMC cultures supplemented with CAg. IL-10, produced in response to burn injuries, is shown to be inhibitory on Th17 cell generation. The high susceptibility of severely burned patients to C. albicans infection might be influenced if burn-associated IL-10 production is intervened.

Adult patients are more catabolic than children during acute phase after burn injury: a retrospective analysis on muscle protein kinetics

PURPOSE

This study was performed to determine if there is an age-related specificity in the response of muscle protein metabolism to severe burn injury during acute hospitalization. This is a retrospective analysis of previously published data.

METHODS

Nineteen adult and 58 pediatric burn-injured patients (age 43.3 ± 14.3 vs. 7.2 ± 5.3 years, adult vs. children) participated in stable isotope [ring-(2)H(5)]phenylalanine (Phe) infusion studies. Femoral arterial and venous blood samples and muscle biopsy samples were collected throughout the study. Data are presented as means ± standard deviation (SD). A p value less than 0.05 was considered statistically significant.

RESULTS

Muscle net protein balance (NB) was higher in children (adult vs. children, -43 ± 61 vs. 8 ± 68 nmol Phe/min/100 ml leg volume, p < 0.05). Muscle protein fractional synthesis rate (FSR) was higher in children (adult vs. children, 0.11 ± 0.05 vs. 0.16 ± 0.10 %/h, p < 0.05). Leg muscle protein breakdown was not different between the groups (adult vs. children, 179 ± 115 vs. 184 ± 124 nmol Phe/min/100 ml leg volume, p > 0.05); synthesis rate was 134 ± 96 and 192 ± 128 nmol Phe/min/100 ml leg volume in adults and children, respectively (p = 0.07). Age significantly correlated with muscle protein NB (p = 0.01) and FSR (p = 0.02); but not with breakdown (p = 0.67) and synthesis (p = 0.07) rates measured by using a three-pool model.

CONCLUSION

In burn injury, the muscle protein breakdown may be affected to the same extent in adults and children, whereas synthesis may have age-related specificities, resulting in a better but still low NB in children.

Endogenous prolactin generated during peripheral inflammation contributes to thermal hyperalgesia

Prolactin (PRL) is a hormone and a neuromodulator. It sensitizes TRPV1 (transient receptor potential cation channel subfamily V member 1) responses in sensory neurons, but it is not clear whether peripheral inflammation results in the release of endogenous PRL, or whether endogenous PRL is capable of acting as an inflammatory mediator in a sex-dependent manner. To address these questions, we examined inflammation-induced release of endogenous PRL, and its regulation of thermal hyperalgesia in female and male rats. PRL is expressed in several types of peripheral neuronal and non-neuronal cells, including TRPV1-positive nerve fibers, preadipocytes and activated macrophages/monocytes localized in the vicinity of nerves. Evaluation of PRL levels in hindpaws and plasma indicated that complete Freund's adjuvant (CFA) stimulates release of peripheral, but not systemic, PRL within 6-48 h in both ovariectomized females with estradiol replacement (OVX-E) and intact male rats. The time course of release varies in OVX-E and intact male rats. We next employed the prolactin receptor (PRL-R) antagonist Δ1-9-G129R-hPRL to assess the role of locally produced PRL in nociception. Applied at a ratio of 1 : 1 (PRL:Δ1-9-G129R-hPRL; 40 nm each), this antagonist was able to nearly (≈ 80%) reverse PRL-induced sensitization of capsaicin responses in rat sensory neurons. CFA-induced inflammatory thermal hyperalgesia in OVX-E rat hindpaws was significantly reduced in a dose-dependent manner by the PRL-R antagonist at 6 h but not at 24 h. In contrast, PRL contributed to inflammatory thermal hyperalgesia in intact male rats at 24, but not at 6 h. These findings indicate that inflammation leads to accumulation of endogenous PRL in female and male rats. Furthermore, PRL acts as an inflammatory mediator at different time points for female and intact male rats.

The evaluation of the adrenal and thyroid axes and glucose metabolism after burn injury in children

INTRODUCTION

Burn injury is an important trauma and can cause many hormonal and metabolic changes in the human body. In contrast to the situation with adults, there are inadequate number of studies on children with this condition. Our aim in this study was to determine the changes in the adrenal, thyroid axes and glucose metabolism in the acute and subacute period and relation to the percent total body surface area (TBSA) burned in children with major burn injury.

PATIENTS AND METHOD

A total of 90 hospitalized children aged 0-13 years (mean: 3.44 +/- 2.90 years) with major fluid burn injury were included in this study. Serum ACTH, cortisol, fasting glucose and insulin and thyroid hormones (free T3 and T4, TSH) were evaluated in the first 24 hours after the burn injury and on day 3 and month 3 consequently in all of the cases. An ACTH stimulation test was performed when necessary. Continuous variables were compared with analysis of variance and categorical variables were compared with the chi-square test. The Pearson correlation was used to determine the relation between ACTH and cortisol and between blood glucose and insulin (on day 1 and 3 and month 3). Also the correlation with the TBSA burned and the hormonal values were evaluated. A p value <0.05 was considered statistically significant.

FINDINGS

ACTH and Cortisol level increased in first 24 hours and decreased significantly by time. The change of ACTH and Cortisol level with time was significantly related to the TBSA burned. ACTH and cortisol levels were found significantly correlated in each time-point, but the correlation was highest in 3rd month. The glucose level in the first 24 hours was significantly higher than day 3 and month 3 levels in all of the children. There was again a significant increase in the serum insulin level in the first 24 hours. However there was no difference between day 1 and 3 serum insulin levels. A correlation was found between serum glucose and insulin on the first day but not on day 3 or month 3. Free T3 and T4 levels increased by time. Pairwise comparisons indicated that 1st day free T3 and T4 level was significantly lower than both 3rd day and 3rd month levels.

CONCLUSION

ACTH, Cortisol and fasting blood glucose level increased significantly however serum insulin level was slightly higher in first 24 hours after burns in children. Thyroid hormones were found to be decreased acute period following burns but staying in normal levels.

Measurement of tissue cortisol levels in patients with severe burns: a preliminary investigation

Introduction

The assessment of adrenal function in critically ill patients is problematic, and there is evidence to suggest that measurement of tissue glucocorticoid activity may be more useful than estimation of plasma cortisol concentrations. Interstitial cortisol concentrations of cortisol represent the available pool of glucocorticoids able to enter the cell and bind to the glucocorticoid receptor. However the concentrations of plasma cortisol may not accurately reflect interstitial concentrations. We elected to perform a preliminary study into the feasibility of measuring interstitial cortisol by microdialysis, and to investigate the relationship between total plasma cortisol, free plasma cortisol and interstitial cortisol in patients with severe burns.

Methods

A prospective observational study carried out in a tertiary intensive care unit. Ten adult patients with a mean total burn surface area of 48% were studied. Interstitial cortisol was measured by microdialysis from patient-matched burnt and non-burnt tissue and compared with that of 3 healthy volunteers. Plasma sampling for estimations of total and free cortisol concentrations was performed concurrently.

Results

In the burn patients, mean total plasma and free plasma cortisol concentrations were 8.8 +/- 3.9, and 1.7 +/- 1.1 mcg/dL, (p < 0.001), respectively. Mean subcutaneous microdialysis cortisol concentrations in the burn and non-burn tissue were 0.80 +/- 0.31 vs 0.74 +/- 0.41 mcg/dL (p = 0.8), respectively, and were significantly elevated over the mean subcutaneous microdialysis cortisol concentrations in the healthy volunteers. There was no significant correlation between total plasma or free plasma and microdialysis cortisol concentrations. Plasma free cortisol was better correlated with total burn surface area than total cortisol.

Conclusions

In this preliminary study, interstitial cortisol concentrations measured by microdialysis in burnt and non-burnt skin from patients with severe thermal injury are significantly elevated over those from healthy volunteers. Plasma estimations of cortisol do not correlate with the microdialysis levels, raising the possibility that plasma cortisol may be an unreliable guide to tissue cortisol activity.

Bench-to-bedside review: Burn-induced cerebral inflammation--a neglected entity?

Severe burn injury remains a major burden on patients and healthcare systems. Following severe burns, the injured tissues mount a local inflammatory response aiming to restore homeostasis. With excessive burn load, the immune response becomes disproportionate and patients may develop an overshooting systemic inflammatory response, compromising multiple physiological barriers in the lung, kidney, liver, and brain. If the blood–brain barrier is breached, systemic inflammatory molecules and phagocytes readily enter the brain and activate sessile cells of the central nervous system. Copious amounts of reactive oxygen species, reactive nitrogen species, proteases, cytokines/chemokines, and complement proteins are being released by these inflammatory cells, resulting in additional neuronal damage and life-threatening cerebral edema. Despite the correlation between cerebral complications in severe burn victims with mortality, burn-induced neuroinflammation continues to fly under the radar as an underestimated entity in the critically ill burn patient. In this paper, we illustrate the molecular events leading to blood–brain barrier breakdown, with a focus on the subsequent neuroinflammatory changes leading to cerebral edema in patients with severe burns.

Epidemiology and risk factors for pathologic scarring after burn wounds

OBJECTIVE

To describe the clinical characteristics of postburn scars and determine the independent risk factors specific to these patients. While burns may generate widespread and disfiguring scars and have a dramatic influence on patient quality of life, the prevalence of postburn pathologic scarring is not well documented, and the impact of certain risk factors is poorly understood.

METHODS

A retrospective analysis was conducted of the clinical records of 703 patients (2440 anatomic burn sites) treated at the Turin Burn Outpatient Clinic between January 1994 and May 15, 2006. Prevalence and evolution time of postburn pathologic scarring were analyzed with univariate and multivariate risk factor analysis by sex, age, burn surface and full-thickness area, cause of the burn, wound healing time, type of burn treatment, number of surgical procedures, type of surgery, type of skin graft, and excision and graft timing.

RESULTS

Pathologic scarring was diagnosed in 540 patients (77%): 310 had hypertrophic scars (44%); 34, contractures (5%); and 196, hypertrophic-contracted scars (28%). The hypertrophic induction was assessed at a median of 23 days after reepithelialization and lasted 15 months (median). A nomogram, based on the multivariate regression model, showed that female sex, young age, burn sites on the neck and/or upper limbs, multiple surgical procedures, and meshed skin grafts were independent risk factors for postburn pathologic scarring (Dxy 0.30).

CONCLUSION

The identification of the principal risk factors for postburn pathologic scarring not only would be a valuable aid in early risk stratification but also might help in assessing outcomes adjusted for patient risk.

S179D prolactin diminishes the effects of UV light on epidermal gamma delta T cells

Epidermal gamma delta T cells (gammadeltaT) and Langerhans cells (LC) are immune cells altered by exposure to ultraviolet radiation (UVB), a powerful stressor resulting in immune suppression. Prolactin (PRL) has been characterized as an immunomodulator, particularly during stress. In this study, we have asked whether separate administration of the 2 major forms of prolactin, unmodified and phosphorylated, to groups of 15 mice (3 experiments, each with 5 mice per treatment group) affected the number and morphology of these epidermal immune cells under control conditions, and following UV-irradiation. Under control conditions, both PRLs reduced the number of gammadeltaT, but a molecular mimic of phosphorylated PRL (S179D PRL) was more effective, resulting in a 30% reduction. In the irradiated group, however, S179D PRL was protective against a UV-induced reduction in gammadeltaT number and change in morphology (halved the reduction and normalized the morphology). In addition, S179D PRL, but not unmodified (U-PRL), maintained a normal LC:gammadeltaT ratio and sustained the dendritic morphology of LC after UV exposure. These findings suggest that S179D PRL may have an overall protective effect, countering UV-induced cellular alterations in the epidermis.

Metabolic response to injury and role of anabolic hormones

PURPOSE OF REVIEW

To provide a short review of the literature describing the hypermetabolic response to injury and potential treatments. Associated findings include changes in inflammatory mediators and secreted hormones.

RECENT FINDINGS

Treatments should be aimed at decreasing the response and potentially the use of anabolic agents. Of note, recent interest in the hyperglycemic response to injury and insulin treatment will be highlighted.

SUMMARY

The current metabolic care of the burned patient including nutrition is now being unfolded. It is relatively clear that anabolic treatment should be considered in all those with severe injury. Timing of the treatment, however, is still a topic of discussion.

Serum IL-18 is increased at early postburn period in moderately burned patients

A severe systemic inflammatory response is usually seen after burn injury. IL-18 enhances the Th1 immune responses in bacterial and viral infections. In order to evaluate the IL-18 serum levels as well as IL-6 and TNF-α at the 48th hour postburn, serial serum samples of 8 burned patients were analyzed. 8 moderately burned patients were included into the study. Serum samples were taken at admission at the 48th hour of postburn. IL-6, IL-18, and TNF-α serum levels were analyzed. Total mean burned surface area (TBSA) was 24.6 ± 5.7% and mean BMI (body mass index) was 24.5 ± 3.4. The patients' age ranged from 17 to 38 (mean 26.3 ± 7.4) years. An increase in sera IL-6, IL-18, and TNF-α was detected at the 48th hour postburn (P < .0001). All patients survived. A marked increase in serum levels of IL-18 as well as the other cytokines evaluated was observed in the moderately burned patients. These three parameters were highly correlated with each other (r > 0.9 and P < .001). This is the first study that shows an increase in serum IL-18 levels at the early postburn period.