Endocrine and molecular responses to surgical stress

Trial watch: beta-blockers in cancer therapy

Compelling evidence supports the hypothesis that stress negatively impacts cancer development and prognosis. Irrespective of its physical, biological or psychological source, stress triggers a physiological response that is mediated by the hypothalamic-pituitary-adrenal axis and the sympathetic adrenal medullary axis. The resulting release of glucocorticoids and catecholamines into the systemic circulation leads to neuroendocrine and metabolic adaptations that can affect immune homeostasis and immunosurveillance, thus impairing the detection and eradication of malignant cells. Moreover, catecholamines directly act on β-adrenoreceptors present on tumor cells, thereby stimulating survival, proliferation, and migration of nascent neoplasms. Numerous preclinical studies have shown that blocking adrenergic receptors slows tumor growth, suggesting potential clinical benefits of using β-blockers in cancer therapy. Much of these positive effects of β-blockade are mediated by improved immunosurveillance. The present trial watch summarizes current knowledge from preclinical and clinical studies investigating the anticancer effects of β-blockers either as standalone agents or in combination with conventional antineoplastic treatments or immunotherapy.

Cortisol and ACTH Measurements at Extubation From Pituitary Surgery Predicts Hypothalamic-Pituitary-Adrenal Axis Function

Context

Early prediction of hypothalamic-pituitary-adrenal (HPA) axis function following transsphenoidal surgery (TSS) can improve patient safety and reduce costs.

Objective

Systematic measurement of ACTH and cortisol at extubation following anesthesia to predict remission from Cushing's disease (CD) and HPA axis preservation following non-CD surgery.

Design

Retrospective analysis of clinical data between August 2015 and May 2022.

Setting

Referral center.

Patients

Consecutive patients (n = 129) undergoing TSS who had perioperative ACTH and cortisol measurements.

Interventions

ACTH and cortisol measurement at extubation. Further serial 6-hourly measurements in CD patients.

Main outcome measures

Prediction of future HPA axis status based on ACTH/cortisol at extubation.

Results

ACTH and cortisol increased sharply in all patients at extubation. CD patients (n = 101) had lower ACTH values than non-CD patients (110.1 vs 293.1 pg/mL; P < 0.01). In non-CD patients, lower plasma ACTH at extubation predicted the need for eventual corticosteroid replacement (105.8 vs 449.1 pg/mL, P < 0.01). In CD patients, the peak post-extubation cortisol at 6 hours was a robust predictor for nonremission (60.7 vs 219.2 µg/dL, P = 0.03). However, normalized early postoperative value (NEPV; the post-extubation values minus the peak preoperative CRH or desmopressin test values) of cortisol reliably distinguished nonremission earlier, at the time of extubation (-6.1 vs 5.9, P = 0.01), and later.

Conclusions

We found that at extubation following TSS, ACTH can predict the need for eventual steroid replacement in non-Cushing's patients. In patients with CD, we found a robust prediction of nonremission with NEPV cortisol at extubation and later.

Aldosterone Increases Vascular Permeability in Rat Skin

The aim of this study was to evaluate the effect of acute aldosterone (ALDO) administration on the vascular permeability of skin. ALDO was injected intradermally into rats, and vascular permeability was measured. Eplerenone (EPL), a selective mineralocorticoid receptor (MR) antagonist, was used. Skin biopsies were carried out for immunohistochemical (IHC) staining, and polymerase chain reactions were performed to analyze the expression of MR, 11β-hydroxysteroid dehydrogenase type 2, von Willebrand factor (vWF), vascular endothelial growth factor (VEGF), and zonula occludens 1. Our study showed the presence of MR in the rat skin vasculature for the first time. It was found that ALDO injection resulted in a more than 30% increase in vascular permeability and enhanced the endothelial exocytosis of vWF. The effect of ALDO diminished after EPL administration. An accumulation of vWF and a reduction in VEGF IHC staining were observed following chronic EPL administration. No effect of ALDO or EPL on the mRNA expression of the studied genes or skin structure was observed. The results suggest that ALDO increases vascular permeability in the skin via an MR-dependent mechanism. This effect of ALDO on skin microcirculation may have important therapeutic implications for diseases characterized by increased levels of ALDO and coexisting skin microangiopathy.

Peri-operative steroid management in the paediatric population

BACKGROUND

Patients with adrenal insufficiency are at risk of adrenal crisis, a potentially life-threatening emergency in the peri-operative period due to their attenuated ability to mount a cortisol response. There is a lack of standardization regarding peri-operative stress-dose glucocorticoids in paediatric clinical practice with the absence of agreed protocols. For the individual patient, the risk of adrenal crisis must be weighed against the potential adverse clinical outcomes associated with unnecessary or supra-physiologic glucocorticoid dosing in susceptible patients. Specific clinical concerns in the paediatric population include osteopenia, growth restriction and increased risk of cardiovascular disease in adulthood. This review aimed to identify and evaluate available literature in the field of peri-operative stress-dose glucocorticoids.

METHODS

A comprehensive literature search was conducted to construct a narrative review.

RESULTS

The outcome of this review identified that paediatric patients, unlike adults, do not show a graded response to surgical stress with implications for glucocorticoid stress dose regimens for general anaesthesia and less invasive surgical procedures. The studies highlight a lack of information on physiological steroid responses to stress situations and differences in the approach to glucocorticoid replacement strategies in the paediatric population.

CONCLUSION

The review identified there is a lack of high-quality paediatric-specific studies evaluating appropriate stress-dose glucocorticoid regimens in paediatric patients with or at risk of adrenal insufficiency. Further research is needed to establish clear evidence-based clinical guidelines for paediatric peri-operative practice regarding steroid stress dosing in adrenal insufficiency. Current knowledge would suggest that a balanced view of risks and benefits should be taken appropriate to the clinical context, to dictate peri-operative stress-dose glucocorticoids use that permits safe perioperative management.

Perioperative stress dose steroid management of children with classical congenital adrenal hyperplasia: Too much or too little?

BACKGROUND

Children with congenital adrenal hyperplasia (CAH) are at risk for adrenal crises in the perioperative period and require higher doses of glucocorticoids. However, there are no specific protocols detailing the appropriate stress dosing required for children with CAH undergoing surgery with anesthesia.

OBJECTIVE

To evaluate CAH patients using our current hydrocortisone stress dose surgical protocol. We hypothesized that current clinical protocols may overestimate the endogenous response to perioperative stress.

STUDY DESIGN

14 children with CAH scheduled to have genital surgery and a control group of 10 unaffected children scheduled to have cardiac or urologic surgery (of a similar duration) were evaluated in a prospective observational study. Urinary free cortisol (UFC) and urinary 17-hydroxycorticosteroids (17-OHCS) per body surface area were measured in the postoperative period.

RESULTS

UFC levels were significantly higher in CAH patients (115.8 ± 24.6 nmol/m²) than in controls (26.5 ± 12.2 nmol/m²), P < 0.05.17-OHCS levels were also higher in CAH patients than in controls (6.5 ± 0.5 nmol/m² vs. 3.4 ± 0.5 nmol/m²), P < 0.05).

CONCLUSION

In the immediate postoperative period, urinary cortisol and its metabolites are significantly higher in pediatric CAH patients receiving stress dose corticosteroids compared to controls. Results suggest that the amount of hydrocortisone given during our stress dose protocol may be higher than physiologic needs. Future dynamic studies are needed to determine appropriate perioperative and postoperative cortisol requirements in pediatric CAH patients in order to develop optimal stress dose regimens.

Cardiac Protective Role of Heat Shock Protein 27 in the Stress Induced by Drugs of Abuse

Heat shock proteins (HSP) are induced after different stress situations. Some of these proteins, particularly HSP-27, function as markers to indicate cellular stress or damage and protect the heart during addictive processes. Morphine withdrawal induces an enhancement of sympathetic activity in parallel with an increased HSP-27 expression and phosphorylation, indicating a severe situation of stress. HSP-27 can interact with different intracellular signaling pathways. Propranolol and SL-327 were able to antagonize the activation of hypothalamic-pituitary adrenal (HPA) axis and the phosphorylation of HSP-27 observed during morphine withdrawal. Therefore, β-adrenergic receptors and the extracellular signal-regulated kinase (ERK) pathway would be involved in HPA axis activity, and consequently, in HSP-27 activation. Finally, selective blockade of corticotrophin releasing factor (CRF)-1 receptor and the genetic deletion of CRF1 receptors antagonize cardiac adaptive changes. These changes are increased noradrenaline (NA) turnover, HPA axis activation and decreased HSP-27 expression and phosphorylation. This suggests a link between the HPA axis and HSP-27. On the other hand, morphine withdrawal increases µ-calpain expression, which in turn degrades cardiac troponin T (cTnT). This fact, together with a co-localization between cTnT and HSP-27, suggests that this chaperone avoids the degradation of cTnT by µ-calpain, correcting the cardiac contractility abnormalities observed during addictive processes. The aim of our research is to review the possible role of HSP-27 in the cardiac changes observed during morphine withdrawal and to understand the mechanisms implicated in its cardiac protective functions.

Pheochromocytoma Multisystem Crisis Triggered by Glucocorticoid Administration and Aggravated by Citrate Dialysis

Pheochromocytoma multisystem crisis is the most severe presentation of pheochromocytoma. We report on a 68-year-old survivor of pheochromocytoma multisystem crisis, whose clinical course was triggered inadvertently by a short innocuous course of oral dexamethasone to suppress inflammation and swelling after a left orbital floor fracture repair. He presented first with severe epigastric pain and headache, and subsequently experienced insults to neurological, cardiac, respiratory, hepatobiliary, renal, and immune system in his prolonged intensive care unit stay. We believe an episode of unexpected hypertensive crisis in the intensive care unit was set off iatrogenically during citrate protocol dialysis.

Psychological and endocrine factors and pain after mastectomy

BACKGROUND

This prospective study was designed to examine the associations of demographic, clinical, psychological and neuroendocrine factors with acute and chronic post-operative pain following partial mastectomy.

METHODS

Sixty-four female patients scheduled for partial mastectomy were enrolled. Pre-operative anxiety/depression was assessed, using the Hospital Anxiety and Depression Scale (HADS). Pre-operative 24-h urinary cortisol levels were measured 2 days before surgery. Post-operative pain was examined using a visual analog scale (VAS) for acute pain on 0-2 post-operative day (POD), and a short-form McGill Pain Questionnaire for chronic pain at 6 months after surgery. In the last 29 subjects, post-operative 24-h urinary cortisol levels were also measured on 0 POD and were subjected to correlation analysis.

RESULTS

Multivariate logistic regression analysis revealed that lower pre-operative cortisol secretion and greater pre-operative anxiety were significantly associated with an increased risk of moderate to severe acute post-operative pain [Odds Ratio (95% Confidence Interval); 0.96 (0.92-0.98), and 1.24 (1.04-1.54)], and that patients with greater pre-operative anxiety and moderate to severe acute pain were more likely to develop chronic post-operative pain [OR (95% CI); 1.63 (1.23-2.40), and 5.07 (1.30-24.6)]. Correlational analysis demonstrated that the post-operative cortisol level was inversely correlated with pre-operative anxiety and the intensity of acute post-operative pain (r = -0.40, p < 0.05, and r = -0.50, p < 0.01), but not with the intensity of chronic pain.

CONCLUSIONS

This study confirms that pre-operative anxiety is associated with both acute and chronic post-operative pain after partial mastectomy. It also suggests that lower perioperative cortisol secretion might be associated with greater acute post-operative pain.

SIGNIFICANCE

Although the associations between psychological stress/stress hormone levels and chronic post-operative pain remain to be determined, pre-operative psychological stress and perioperative cortisol levels are correlated with acute post-operative pain.

WITHDRAWN: Supplemental perioperative steroids for surgical patients with adrenal insufficiency

July 30 2020: This Cochrane Review has been withdrawn from publication. The review was temporarily withdrawn in 2013. Cochrane Anaesthesia has now decided to permanently withdraw the review. Cochrane Anaesthesia intends to publish a new review on this topic in the future. 

October 17 2013: Following comments received via direct correspondence which have challenged the eligibility criteria and interpretation of the evidence summarized in this review, the CARG editorial team has decided to temporarily withdraw the review from the CDSR whilst the comments are considered further and addressed.

The editorial group responsible for this previously published document have withdrawn it from publication.

Supplemental perioperative steroids for surgical patients with adrenal insufficiency

BACKGROUND

Adrenal crisis is a life threatening condition which can be induced by stress during surgery in patients with adrenal insufficiency. This may be prevented by perioperative administration of high doses of steroids. There is disagreement on whether supplemental perioperative steroids are required and, when administered, on the amount and frequency of doses. The review was originally published in 2009 and was updated in 2012.

OBJECTIVES

To assess whether it is necessary to administer supplemental perioperative steroids in adult patients on maintenance doses of glucocorticoids because of adrenal insufficiency.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2012, Issue 2); MEDLINE (1966 to February 2012); EMBASE (1980 to February 2012); LILACS (1982 to May 2012); and the databases of ongoing trials. We handsearched the Journal of Clinical Endocrinology and Metabolism (1982 to 2008), Clinical Endocrinology (1972 to 2008), Surgery (1948 to 1994), Annals of Surgery (1948 to 1994), and Anaesthesia (1948 to 2001). The original search was performed in January 2009.

SELECTION CRITERIA

We included randomized controlled trials that compared the use of supplemental perioperative steroids to placebo in adult patients on maintenance doses of steroids and who required surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for missing information. We used mean differences and standard deviations to summarize the data for each group.

MAIN RESULTS

Two trials involving 37 patients were included. These studies reported that supplemental perioperative steroids were not required during surgery for patients with adrenal insufficiency. Neither study reported any adverse effects or complications in the intervention and control groups. Both studies were graded as having a high risk of bias.

AUTHORS' CONCLUSIONS

Owing to the small number of patients, the results may not be representative. Based on current available evidence, we are unable to support or refute the use of supplemental perioperative steroids for patients with adrenal insufficiency during surgery.

Ultraviolet-A irradiation to the eye modulates intestinal mucosal functions and properties of mast cells in the mouse

We previously reported that topical irradiation of the eye by ultraviolet-B (UVB) activated hypothalamo-pituitary-adrenal axis (HPA-A) of the mouse to increase 3, 4-dihydroxyphenylalanine (DOPA)-positive melanocytes in the skin by an inducible nitric oxide synthase (iNOS)-dependent mechanism. This work demonstrates that irradiation of the eye by ultraviolet-A (UVA) specifically increased DOPA-positive cells in the mucosa of the jejunum and colon of C57BL/6J mice by some HPA- and iNOS-independent mechanism. UVA-induced increase in DOPA-positive cells in the intestine was inhibited by the administration of hexamethonium or prazosin plus propranolol, blockers for the sympathetic nervous system. UVA irradiation of the eye increased DOPA- and histidine decarboxylase (HDC)-positive cells in the intestinal mucosa of both C57BL/6J and WBB6F1/J mice but not in the mutant strain W/Wv of the latter that lack mast cells. UVA irradiation of the eye suppressed the intestinal peristalsis of control, hypophysectomized or iNOS(-/-) C57BL/6J mice by the mechanism that was inhibited by hexamethonium or prazosin plus propranolol. These observations suggest that UVA irradiation of the eye stimulated the sympathetic nervous system to increase the mucosal DOPA- and HDC-positive mast cells and suppressed the peristalsis of the small intestine of the mouse.

Dose-response relationship between norepinephrine and erythropoiesis: evidence for a critical threshold

BACKGROUND

Severe traumatic injury elicits a neuroendocrine response that activates the sympathetic nervous system. Our previous work suggests that norepinephrine (NE) influences the bone marrow (BM) erythropoietic response. However, the dose-response relationship between NE and erythropoiesis remains unclear.

MATERIALS AND METHODS

Two days following chemical sympathectomy with 6-hydroxydopamine (6-OHDA) or injection with saline vehicle (SHAM), male Sprague-Dawley rats were infused continuously with either saline (NS) or increasing doses of NE for 5 d via osmotic pumps. Erythropoiesis was assessed by growth of erythroid progenitor colonies (BFU-E and CFU-E for early and late progenitors, respectively).

RESULTS

Following chemical sympathectomy with 6-OHDA, both BFU-E and CFU-E growth is inhibited (42%∗ and 43%∗ versus 100% SHAM, ∗P < 0.05). SHAM rats with continuous infusion of exogenous NE show a clear dose-response inhibition of both BFU-E and CFU-E colony growth. In the 6-OHDA rats, continuous infusion of NE restored BFU-E and CFU-E growth at 10(-8) g/h and 10(-9) g/h, respectively.

CONCLUSIONS

Erythroid precursor colony growth is inhibited in sympathectomized rats. In addition, supraphysiologic doses of exogenous NE inhibit normal erythropoiesis in a dose-dependent fashion. Following chemical sympathectomy with 6-OHDA, exogenous NE restores erythropoiesis in a narrow window. Therefore, NE has a complex interaction within the BM and the elevation of NE following traumatic injury impacts BM erythropoietic function.

Targeted antisense modulation of inflammatory cytokine receptors

Antisense technology is potentially a powerful means by which to selectively control gene expression. We have used antisense oligonucleotides to modulate the response of the hepatoma cell line, HepG2, to the inflammatory cytokine, IL-6, by inhibiting the expression of its multifunctional signal transducer, gp130. HepG2 cells respond to IL-6 by upregulating acute phase proteins, such as haptoglobin, by five- to tenfold. Gp130 is central to this response, as the upregulation of haptoglobin is almost completely blocked by the addition of high concentrations ( approximately 100 microg/ml) of a monoclonal antibody to gp 130. Antisense oligodeoxynucleotides complementary to the mRNA encoding gp 130 inhibited the upregulation of haptoglobin by IL-6-stimulated HepG2 cells by about 50%. However, a nonsense sequence also inhibited haptoglobin secretion by about 20%. To improve the specificity and efficiency of action, we targeted the antisense oligonucleotides to HepG2 cells using a conjugate of asialoglycoprotein-poly-L-lysine. The targeted antisense reduced the binding of IL-6 to HepG2 cells, virtually eliminating high affinity binding. In addition, it inhibited haptoglobin upregulation by over 70%. Furthermore, the dose of targeted antisense required for biological effect was reduced by about an order of magnitude as compared with unconjugated antisense. These results demonstrate the potential of antisense oligonucleotides as a means to control the acute phase response as well as the need for a greater understanding of the mechanism and dynamics of antisense molecules as they are developed toward therapeutic application.

Supplemental perioperative steroids for surgical patients with adrenal insufficiency

BACKGROUND

Adrenal crisis is a life threatening condition which can be induced by stress during surgery in patients with adrenal insufficiency. This may be prevented by perioperative administration of high doses of steroids. There is disagreement on whether supplemental perioperative steroids are required and, when administered, on the amount and frequency of doses.

OBJECTIVES

To assess whether it is necessary to administer supplemental perioperative steroids in adult patients on maintenance doses of glucocorticoids because of adrenal insufficiency.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, Issue 1); MEDLINE (1966 to January 2009); EMBASE (1980 to January 2009); LILACS (1982 to January 2009); and the databases of ongoing trials. We handsearched the Journal of Clinical Endocrinology and Metabolism (1982 to 1997), Clinical Endocrinology (1972 to 1997), Surgery (1948 to 1994), Annals of Surgery (1948 to 1994), and Anaesthesia (1948 to 2000).

SELECTION CRITERIA

Randomized, controlled trials that compared the use of supplemental perioperative steroids to placebo in adult patients on maintenance doses of steroids who required surgery.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. Study authors were contacted for missing information. We used mean differences and standard deviations to summarize the data for each group.

MAIN RESULTS

Two trials involving 37 patients were included. These studies reported that supplemental perioperative steroids were not required during surgery for patients with adrenal insufficiency. Neither study reported any adverse effects or complications in the intervention and control groups.

AUTHORS' CONCLUSIONS

Owing to the small number of patients, the results may not be representative. Based on current available evidence, we are unable to support or refute the use of supplemental perioperative steroids for patients with adrenal insufficiency during surgery.

Centrifugal acceleration to 3Gz is related to increased release of stress hormones and decreased mood in men and women

It has been suggested that the central and peripheral neural processes (CPNP) are affected by gravitational changes. Based on the previous experiments during parabolic flights, central and peripheral changes may not only be due to the changed gravitational forces but also due to neuroendocrine reactions related to the psycho-physiological consequences of gravitational changes. The present study focuses on the interaction of neuroendocrine changes and the physical and mental states after acceleration to three-time terrestrial gravity (3Gz). Eleven participants (29.4+/-5.1 [SD] years (male (n=8): 30+/-5.1 years; female (n=3): 27.7+/-2.1 years) underwent a 15 min acceleration to 3Gz in a human centrifuge. Before and after the acceleration to 3Gz circulating stress hormone concentrations (cortisol, adrenocorticotropic hormone (ACTH), prolactin, epinephrine, norepinephrine) and perceived physical and mental states were recorded. A second control group of 11 participants underwent the same testing procedure in a laboratory session. Serum cortisol concentration during exposure to the centrifugal acceleration increased by 70%, plasma concentration of ACTH increased threefold, prolactin twofold, epinephrine by 70% and norepinephrine by 45%, whereas the perceived physical well-being decreased. These findings demonstrate that psycho-physiological changes have to be regarded as a relevant factor for the changes in CPNP during phases of hypergravity exposure.

Nutritional modulation of protein metabolism after gastrointestinal surgery

BACKGROUND

The metabolic response to surgery includes alterations in protein metabolism, resulting in a net loss of proteins. Protein hypercatabolism is considered an unavoidable consequence of injury, and an important source of morbidity and mortality. Our purpose was to determine the effect of nutrition on protein metabolism following gastrointestinal surgery, and to elucidate whether postoperative protein loss can be prevented with adequate nutritional support.

METHODS

Patients who had undergone gastrointestinal surgery were given four different parenteral nutritions with increasing glucose, lipid and amino acid content during the 7 days following surgery. Nitrogen balance, protein synthesis and protein breakdown were determined using in vivo stable isotope labelling. Other metabolites (3-methylhistidine, creatinine, urea, cortisol, glucose, insulin, amino acids and C-reactive protein) were measured.

RESULTS

A nutrition-dependent alteration of protein metabolism was found in response to surgical injury. Nutrition modified nitrogen balance, whole-body protein breakdown and, to a lesser extent, whole-body protein synthesis and muscle protein breakdown. The low-energy parenteral nutrition without amino acids produced a negative nitrogen balance (postoperative day 7=-0.381 g protein kg(-1)day(-1)) and important alterations in postoperative protein metabolism that did not normalize during the study period (day 7 protein synthesis=239% and protein breakdown 217% vs preoperative). Patients receiving the two low energy parenteral nutritions containing amino acids had a less negative nitrogen balance (day 7=-0.011 and -0.133 g protein kg(-1)day(-1)) and a transient increase in protein metabolism. The complete parenteral nutrition maintained, during all studied days, protein metabolism parameters within the preoperative reference range (synthesis day 2=92%, day 4=110% day 7=79%; breakdown day 2=85%, day 4=80%, day 7=76% vs preoperative) and a positive nitrogen balance (day 2=+0.0387, day 4=+0.578 and day 7=+0.227 g protein kg(-1)day(-1)).

CONCLUSION

Complete nutritional support can prevent protein loss after gastrointestinal surgery and maintain protein metabolism without alterations.

Parabolic flight experience is related to increased release of stress hormones

Numerous studies have shown significant effects of weightlessness on adaptational processes of the CNS, cardiovascular and/or muscular system. Most of these studies have been carried out during parabolic flights, using the recurring 20 s of weightlessness at each parabola. Although some of these studies reported on potential influences not only of weightlessness but also of the stressful situation within a parabolic flight, especially provoked by the ongoing changes between 1.8, 1 and 0 G, so far there seems to be only marginal information about objective parameters of stress evoked by parabolic flights. By collecting blood samples from a permanent venous catheter several times during parabolic flights, we were able to show an increase of prolactin, cortisol and ACTH in the course of a 120 min flight. We conclude, therefore, that previous reported effects of weightlessness on adaptational processes may be affected not only by weightlessness but also by the exposure to other stressors experienced within the environment of a Zero-G airbus.

Spatio-temporal distribution of apoptosis and the modulators thereof following a cortical microinfarct in rat brain

Two mechanisms of brain cell death coexist, necrosis and apoptosis. We investigated the correlation between the apoptotic index and the expression of apoptosis modulators and stress response in an ultraviolet-induced cortical microinfarct. Adult rat neocortex was exposed to an ultraviolet beam and brains removed at different intervals after injury were paraffin-embedded and processed for TUNEL assay and immunohistochemistry against apoptotic modulators Bax and Bcl-2, and stress protein HSP70. During the 12-72h postirradiation period, apoptotic nuclei decreased from 11% to 4% in the infarcted area whereas only 1.2% of such nuclei was seen in the perilesional area. While Bcl-2 was always negative in the lesion focus, Bax was positive at all survival times, mainly in glial cells. HSP70 was expressed over a broad area of the ipsilateral hemisphere from 3h after brain injury, firstly in neurons and progressively in glial cells and finally in endothelium. At longer survival times, positive cells could be also seen in the contralateral hemisphere. Apoptosis seems to play only a quantitatively modest role in the progression of brain damage in penumbra areas despite the wide expression of pro-apoptotic factors. On the other hand HSP70 appears to be one of the main protective responses to injury stress.

Endocrine function is not impaired in patients with a continuous MicroMed–DeBakey axial flow pump

OBJECTIVES

Pulsatile blood flow has been regarded to be of importance for the regulation of endocrine organs. A new generation of continuous flow mechanical blood pumps is now available for clinical application. Patients with implanted MicroMed-DeBakey axial pumps show nonphysiologic low-pulsatile blood flow profiles, and therefore it appeared to be of interest to evaluate their possible effect on the endocrine system.

METHODS

Eight male patients and 1 female patients (mean age, 51 +/- 10 years) with end-stage left-sided heart failure were implanted with a MicroMed-DeBakey axial pump. After a mean period of 67 +/- 19 days, basal pituitary hormone concentrations and their responses to a bolus injection of hypothalamic releasing hormones were tested. In addition, thyroid hormones, testosterone, and plasma and urinary catecholamine levels were measured at baseline.

RESULTS

Administration of the hypothalamic releasing hormones revealed normal responses of all pituitary hormones (adrenocorticotropic hormone, thyroid-stimulating hormone, luteinizing hormone, and prolactin), except for growth hormone, the response of which was slightly impaired (10.2 +/- 6.8 vs 19.9 +/- 6.5 ng/L, P < .05). Also, the cortisol response to the corticotropin-releasing hormone-stimulated adrenocorticotropic hormone release was normal, as were basal concentrations of thyroid hormones (triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine), testosterone, and urinary catecholamines.

CONCLUSIONS

Implantation of a continuous flow axial pump with low-pulsatile blood flow profile appears to have no major effect on the hypothalamic-pituitary-endorgan system and sympathoadrenal functions. This finding is reassuring for the growing number of patients treated with this convenient new pump and could contribute considerably to their prognosis and quality of life.

Androstenetriol improves survival in a rodent model of traumatic shock

Trauma results in activation of the hypothalamic-pituitary-adrenal axis to mediate a cascade of neurohormonal changes as a defensive mechanism. Its prolongation, however, leads to a hypermetabolic, hypoperfused, and immunosuppressed state, setting the stage for subsequent sepsis and organ failure. Androstenetriol (5-androstene-3beta, 7beta, 17betatriol - AET), a metabolite of dehydroepiandrosterone, up-regulates the host immune response markedly, prevents immune suppression and controls inflammation, leading to improved survival after lethal infections by several diverse pathogens and lethal radiation. Such actions may be useful in improving survival from traumatic shock.

HYPOTHESIS

The neurosteroid AET will increase survival following traumatic shock.

METHODS

A combat relevant model of traumatic shock was used. Male Sprague-Dawley rats were anesthetized, catheterized and subjected to soft tissue injury (laparotomy). Animals were allowed to regain consciousness over the next 0.5 h and then bled 40% of their blood volume over 15 min. Forty-five minutes after the onset of hemorrhage animals were randomized to receive either a single subcutaneous dose of AET (40 mg/kg, sc) or vehicle (methylcellulose). Volume resuscitation consisted of l-lactated Ringer's (three times the shed blood volume), followed by packed red blood cells (one-third shed red cell volume). Animals were observed for three days.

RESULTS

A total of 24 animals were studied. Of the 12 animals randomized to receive AET, all (100%) survived compared to 9 of 12 animals (75%) randomized to receive the vehicle (p < 0.05).

CONCLUSION

AET significantly improved survival when administered subcutaneously in a single dose in this rodent model of traumatic shock. Further survival and mechanism studies are warranted.

The impact of a hypercatecholamine state on erythropoiesis following severe injury and the role of IL-6

BACKGROUND

Severe traumatic injury can lead to hemorrhagic shock-induced bone marrow (BM) dysfunction resulting in persistent anemia. The hypercatacholamine state that accompanies severe injury has been shown to impact the growth of erythroid progenitors. IL-6 has a role both in the acute phase response of trauma and has been implicated in the development of anemia. The aim of this study was to investigate the severity of a hyper-adrenergic stimulus on pluripotent progenitors (GEMM-CFU) as well as erythroid progenitors (BFU-E and CFU-E) and the potential regulatory role of IL-6.

METHODS

Normal human BM mononuclear cells were isolated and erythropoiesis was assessed by the growth of GEMM-CFU, BFU-E and CFU-E in the presence of adrenergic agonists, norepinephrine (NE) and epinephrine (EPI), at increasing concentrations. Similarly, normal BM stroma cells were grown to confluence then incubated with NE and EPI. Supernatant was harvested and IL-6 levels were determined using ELISA.

RESULTS

Under physiologic conditions (10(-7) M), NE and EPI increase BFU-E and CFU-E growth (374% and 177% versus 100% control). At severe stress levels (10(-3) M), NE and EPI completely inhibited BFU-E and CFU-E growth (5% and 4% versus 100% control). GEMM-CFU growth was increased by NE and not EPI at 10(-7) M. The presence of NE and EPI increased IL-6 levels in a dose-dependent fashion.

CONCLUSIONS

The proliferative effect of adrenergic agonists at physiologic levels on normal erythropoiesis begins early during erythroid differentiation. At severe stress levels, BFU-E and CFU-E growth is inhibited. The erythropoietic dysfunction and resultant anemia seen following severe injury may be due to the presence of a severe hypercatecholamine state and may be mediated by IL-6.

Immune Reactivity Is More Suppressed in Patients with Alcoholic Liver Disease than in Patients with Virus-Induced Cirrhosis after CRH Stimulation

BACKGROUND

The most frequent diagnoses for liver transplantation are virus-induced cirrhosis (VIC) and alcoholic liver disease (ALD), after an abstinence period of at least 6 months. Chronic ethanol consumption has been linked to an abnormal neuroendocrine-immune axis and to an altered surgical stress response inducing an increased infection rate. Preoperative stress testing might be relevant to detect stress-induced immune alteration. The aim of this study was to investigate the preoperative stress-like response to corticotrophin-releasing-hormone challenge (CRH) of patients with ALD compared with patients with VIC and their immune sequelae.

METHODS

Nine patients with ALD and 8 patients with VIC were included in this clinical study prior to transplantation. All patients received CRH in the morning. Blood samples were drawn before and after stress testing.

RESULTS

In response to CRH, the ALD patients showed a significant decrease in the plasma interleukin (IL)-6/IL-10 ratio. After lipopolysaccharide stimulation of whole blood from CRH-challenged ALD patients, IL-10 increased significantly. The cytotoxic T1-(Tc1) to cytotoxic T2 (Tc2) ratio was significantly decreased in ALD patients after the stress test. Infections occurred significantly more often in ALD patients within the past year before study inclusion.

CONCLUSIONS

ALD patients showed a stronger anti-inflammatory immune status and response than VIC patients. This difference was associated with a higher infection rate despite a median alcohol abstinence time of 3.5 years. Although an altered immune response is well known among patients with actual alcohol-use disorders, to the best of our knowledge, it is not described in patients after such a long abstinence time.

Ketamine reduces mortality of severely burnt rats, when compared to midazolam plus fentanyl

Ketamine can provide protective effects, through its anti-inflammatory properties, as shown in animal models of septic shock and endotoxemia, and has elicited the heat-shock response (HSR) in experimental studies. The HSR has reduced the mortality after severe burns in rats. This study has tested the hypothesis that ketamine could be protective in experimental burns and that it could generate the HSR. One hundred and twenty adult male Fischer rats were randomly divided into five groups. Rats in the first group (n = 20) were sham-anesthetized. In the second group (n = 20), rats were anesthetized with ketamine and shaved. In the third group (n = 20) rats were anesthetized with midazolam plus fentanyl and shaved. In the fourth group (n = 30), rats were anesthetized with ketamine, shaved and submitted to 29% body surface third-degree burns using a brass bar. In the fifth group (n = 30), rats were anesthetized with midazolam plus fentanyl, shaved and submitted to 29% body surface third-degree burns using a brass bar. Mortality rates were measured at 1, 2, 3, 5, 7, 10, 15 and 25 days. Liver and lung samples were collected from all groups for heat-shock protein 70 (HSP70) detection. No animals died in the first, second or third group. Animals anesthetized with ketamine showed significantly decreased mortality, as compared to those anesthetized with midazolam plus fentanyl, from day 2 to day 10 (P < 0.01, Fischer's exact test) and from day 10 to day 25 (P < 0.05). HSP70 was positive in the lungs of animals from all groups, without any differences among them, and was found in none of the liver samples. In conclusion, the mortality was significantly lesser in ketamine-anesthetized burnt rats than in burnt animals anesthetized with midazolam plus fentanyl. Ketamine has not elicited the HSR in this model of experimental burns and, therefore, its protective effects were not shown to be mediated through this mechanism.

[Determination of beta-endorphin plasma concentrations in surgical patients with acute abdominal pain]

Abdominal pain and surgery, frequently associated with this kind of pain, modify plasma levels of stress-hormones and iniciates the response of endogenous analgetic system. The aim of this study was to determine serum concentration of beta-endorphine in patients with acute abdominal pain (n=12), which were surgically treated. Serum concentration of beta-endorphin was measured on five data points: before, during and after surgery. During abdominal surgery serum concentration of beta-endorphin was increased by 7% compared to preoperative period; in postoperative period the concentration continued to rise and remained increased within next hours. The maximal levels of beta-endorphine were not observed during, and immediately after surgery. Postoperatively, between 6 and 8 p.m. on the day of surgery, maximal level of beta-endorphin was noted, which was even ten times higher than to preoperative value. Plasma level of beta-endorphin fell to the baseline values 24 hours after surgery. In conclusion, abdominal surgery induces a postponed (delayed) increase in serum beta-endorphine levels, which are associated with modulation of preoperative, intraoperative and postoperative pain perception.

The response of vestibulo-ocular reflex pathways to electrical stimulation after canal plugging

The vestibulo-ocular reflex (VOR) allows clear vision during head movements by generating compensatory eye movements. Its response to horizontal rotation is reduced after one horizontal semicircular canal is plugged, but recovers partially over time. The majority of VOR interneurons contribute to the shortest VOR pathway, the so-called three-neuron arc, which includes only two synapses in the brainstem. After a semicircular canal is plugged, transmission of signals by the three-neuron arc originating from the undamaged side may be altered during recovery. We measured the oculomotor response to single current pulses delivered to the vestibular labyrinth of alert cats between 9 h and 1 month after plugging the contralateral horizontal canal. The same response was also measured after motor learning induced by continuously-worn telescopes (optically induced motor learning). Optically induced learning did not change the peak velocity of the evoked eye movement (PEEV) significantly but, after a canal plug, the PEEV increased significantly, reaching a maximum during the first few post-plug days and then decreasing. VOR gain also showed transient changes during recovery. Because the PEEV occurred early in the eye movement evoked by a current pulse, we think the observed increase in PEEV represented changes in transmission by the three-neuron arc. Sham surgery did not result in significant changes in the response to electrical stimulation or in VOR gain. Our data suggest that different pathways and processes may underlie optically induced motor learning and recovery from plugging of the semicircular canals.

Epinephrine as a mediator of pulmonary neutrophil sequestration

Neutrophil-mediated lung injury is a potential complication of trauma and sepsis. Concomitant with trauma and sepsis, there is an immediate and sustained systemic elevation of catecholamines including epinephrine. In the absence of trauma or sepsis, we examined whether epinephrine contributes to the accumulation of neutrophils in the lung. Eight- to 12-week-old male CF-1 mice were injected i.p. with 0.2 mL of normal saline or epinephrine (0.1-5.0 mg/kg). An unmanipulated control group was included to examine the stress of i.p. injection. Animals were sacrificed at predetermined time points, and lung and spleen were harvested. PMN accumulation was assessed by using a myeloperoxidase (MPO) assay, which is an indirect marker for neutrophil presence. Morphometric analysis of lung tissue was performed by a pathologist blinded to the groups. Increasing epinephrine doses resulted in a significantly increased accumulation of pulmonary neutrophils compared with normal saline. The stress of normal saline injection also resulted in a significantly greater pulmonary neutrophil accumulation than unmanipulated controls. The effects of epinephrine on pulmonary neutrophil accumulation were greatest at 2 h, but they were not significantly different from saline-injected controls by 12 h. These results correlated with histological analysis. There were no significant differences in spleen MPO activity between groups, suggesting an organ-specific mechanism of epinephrine-induced pulmonary neutrophil sequestration. In the absence of trauma, shock, or infection, epinephrine results in the accumulation of neutrophils in murine lungs. The finding that "injection stress" increased lung neutrophil sequestration suggests the possibility that this mechanism may be physiologically relevant. Thus, epinephrine release in trauma may set the stage for development of neutrophil-mediated acute lung injury.

Effects of confinement (110 and 240 days) on neuroendocrine stress response and changes of immune cells in men

The aim of the study was to evaluate the effects of long-term confinement on stress-permissive neuroendocrine and immune responses in humans. Two groups of four male subjects were confined 240 days (group 240) or 110 days (group 110) in two space modules of 100 or 200 m3, respectively. During confinement, none of the volunteers developed psychic stress as could be examined and verified by a current stress test. However, in group 240 but not in group 110, the diurnal rhythm of cortisol secretion was slightly depressed and the urine excretion of norepinephrine significantly increased. The innate part of the immune system became activated as seen by a rise in the number of circulating granulocytes and the enhanced expression of beta2-integrins. In contrast, the ratio of T-helper to T-suppressor cells decreased. All these effects, observed during confinement, were even more pronounced in both groups when values of endocrinological and immunological parameters were compared between before and 1 wk after the end of the confinement period. Hence, return to normal life exerts pronounced effects to a much higher degree, irrespective of how long or under which conditions individuals were confined. Because the delayed-type hypersensitivity skin reaction against recall antigens remained unaffected, it is to be presumed that confinement appears to induce distinct sympathoadrenergic activation and immunological changes but no clinically relevant immunosuppression.

The effect of partial vitrectomy on blood-ocular barrier function in the rabbit

PURPOSE

To compare ocular vascular permeability in the rabbit after vitrectomy as assessed by contrast-enhanced magnetic imaging (CE-MRI) and measurements of aqueous and vitreous humor protein concentration.

METHODS

Partial vitrectomies were performed, irrigating with BSS or BSS PLUS. Post-operative vascular leakage was determined by CE-MRI following intravenous administration of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). Aqueous and vitreous protein concentrations were quantified by standard biochemical assay. ERG evaluations were performed on postoperative days 1, 3, and 7.

RESULTS

Using BSS as irrigant, breakdown of the inner blood-retinal barrier (BRB) occurred in 4/7 eyes on post-operative day 1. The rate of Gd-DTPA leakage was significantly greater on postoperative day 1 than that in unoperated, control eyes, but declined approximately 50% by day 3. At both time points, outer BRB breakdown was restricted to the sclerotomy wounds. No BRB leakage was detectable in control eyes. Blood-aqueous barrier (BAB) leakage was bilateral on day 1. Significantly greater Gd-DTPA leakage occurred in the operated eye than in the nonsurgical contralateral eye. On day 3, approximately 40% bilateral reduction in leakage indicated resolution of BAB leakage. Notably, Gd-DTPA leakage of the BAB and BRB was significantly reduced in the BSS PLUS treated group. In contrast to MRI assessments, protein concentrations of the aqueous and vitreous in the surgical eye showed no detectable differences between BSS and BSS PLUS. Concurrent with the transient loss of ocular barrier function, ERG responses also declined. However, by day 7 greater than 90% recovery was noted in BSS PLUS treated animals but not in the BSS treatment group.

CONCLUSIONS

CE-MRI is capable of detecting subtle changes in vascular permeability following ocular surgery. Advantages of using BSS PLUS compared to BSS as the irrigating solution can be detected using this technique. BSS PLUS's protection of barrier function is consistent with a rapid recovery in retinal function not observed in BSS treated eyes.

Inter-individual differences in cytokine release in patients undergoing cardiac surgery with cardiopulmonary bypass

Cardiac surgery with cardiopulmonary bypass (CPB) leads to a systemic inflammatory response with secretion of cytokines (e.g. IL-6, TNF-alpha, IL-1 beta and sIL-2R). The objective of the following study was to investigate in vitro and in vivo cytokine responses and white blood cell counts (WBC) of patients with high versus low cytokine secretion after a coronary artery bypass grafting (CABG) procedure. Twenty male patients undergoing elective CABG surgery with CPB under general anaesthesia were enrolled in the study. On the day of surgery (postoperatively), serum levels of TNF-alpha and IL-1 beta were significantly higher in patients of the high IL-6 level group compared to the respective values in the patient group with low IL-6 levels. The inter-individual differences in IL-6 release in patients undergoing CABG surgery with CPB were accompanied by differences in the release of other cytokines, such as TNF-alpha, IL-1 beta and sIL-2R. To understand whether genetic background plays a role in influencing cytokine plasma levels under surgical stress, we examined the distribution of polymorphic elements within the promoter regions of the TNF-alpha and IL-6 genes, and determined their genotype regarding the BAT2 gene and TNF-beta intron polymorphisms. Our preliminary data suggests that regulatory polymorphisms in or near the TNF locus, more precisely the allele set 140/150 of the BAT2 microsatellite marker combined with the G allele at -308 of the TNF-alpha gene, could be one of the genetic constructions providing for a less sensitive response to various stimuli. Our results suggest: (1) close relationships between cytokine release in the postoperative period, and (2) inter-individually varying patterns of cytokine release in patients undergoing CABG surgery with CPB.

Evidence for activin A and follistatin involvement in the systemic inflammatory response

The inflammatory cascade is a multifactorial process regulated by interwoven cytokine and growth factor networks. This review summarizes the emerging evidence that implicate activin A and follistatin in inflammatory processes. Our recent studies have determined that activin A is released early in the cascade of circulatory cytokines during systemic inflammatory episodes, roughly coincident with tumour necrosis factor (TNF)-alpha and before interleukin (IL)-6 and follistatin. The source(s) of this activin A are not yet established, but prime candidates are monocytes/macrophages, other immune cell types or vascular endothelial cells. Clinical data are limited, but activin beta(A) subunit mRNA or activin A protein is elevated in inflammatory bowel diseases and inflammatory arthropathies, and circulating concentrations of follistatin are elevated in patients with sepsis. In more mechanistic approaches, in vitro studies show that activin A can have both pro- and anti-inflammatory actions on key inflammatory mediators such as TNFalpha, IL-1beta and IL-6. Furthermore, there is emerging understanding of how the intracellular signaling pathway for activin A, incorporating Smads, may interact with and be modulated by other key regulatory cytokines and growth factors.

Simulated microgravity, psychic stress, and immune cells in men: observations during 120-day 6 degrees HDT

Because 6 degrees head-down tilt (HDT) is an established method to mimic low gravity on earth, the aim of the present study was to determine the effects of 120-day HDT on psychic stress and peripheral blood immune cells in six healthy male volunteers. Psychological state was assessed by a current stress test, and cortisol was measured in saliva. During HDT, all volunteers developed psychic stress, and the diurnal rhythm of cortisol secretion was significantly altered. In addition, urine excretion of dopamine and norepinephrine increased. The innate part of the immune response was activated, as evidenced by the increase in the expression of beta(2)-integrins on polymorphonuclear leukocytes and a rise in the number of circulating natural killer (NK) cell lymphocytes. The ratio of T-helper to T-cytotoxic and T-suppressor cells decreased, whereas no changes in T and B lymphocytes were observed. Plasma levels of interleukin-6 increased significantly and returned to basal levels after the end of the HDT period. Thus 6 degrees HDT appears to be a valid model to induce psychic stress and neuroendocrine-related changes in the immune system, changes that might also be encountered by astronauts and cosmonauts during long-duration spaceflights.

Endocrine response to surgical stress in three patients over 100 yr

PURPOSE

To report the change of plasma epinephrine, norepinephrine, cortisol, plasma renin activity, plasma aldosterone and plasma atrial natriuretic peptide during general anesthesia in three centenarian patients.

CLINICAL FEATURES

Three patients aged 101, 101 and 102-yr, underwent a screw fixation of femoral fracture under general anesthesia. Plasma concentrations of epinephrine, norepinephrine, cortisol, renin activity, aldosterone and atrial natriuretic peptide were measured before the induction of anesthesia, 15 min after incision and 60 min after the end of surgery. Plasma epinephrine concentrations in the three patients increased from 419, 344 and 377 pg x ml(-1) before anesthesia to 688, 534 and 478 pg x ml(-1) 15 min after skin incision. Plasma norepinephrine concentrations increased markedly from 408, 513 and 606 pg x ml(-1) before anesthesia to 2950, 1864 and 1574 pg x ml(-1) 15 min after skin incision. The cortisol response to surgery was similar to that of young adults. Plasma aldosterone and renin activity was low throughout anesthesia. Plasma atrial natriuretic peptide increased from 353, 367 and 109 pg x ml(-1) before induction to 479, 487 and 168 pg x ml(-1) 15 min after skin incision.

CONCLUSION

Plasma norepinephrine concentration in patients over 100 yr increased markedly during anesthesia, while plasma renin activity and aldosterone were lower.

Plasma inflammatory cytokine response to surgical trauma in chronic depressed patients

We investigated inflammatory cytokine response in chronic depressed patients during abdominal surgery. Twenty-five major depressed patients (Group D) and twenty-five patients (Group C) as the control were studied. Plasma interleukin 6 (IL-6), interleukin 8 (IL-8) and tumour necrosis factor-alpha (TNF-alpha) concentrations were measured before and at 15 min after induction of anesthesia, the end of surgery, 24 h and 3 days after the operation. Plasma IL-6 concentrations in Group D at the end of the operation and 24 h after surgery were significantly lower than those of Group C. The plasma IL-6 concentration (87.1+/-55.3 pg/ml) of patients scoring more than 18 points in the Hamilton depression-rating score at the end of the operation was significantly higher than 57.5+/-76.7 pg/ml of patients scoring less than 18 points. Plasma IL-8 concentration (6.1+/-3.2 pg/ml) in Group D at the end of the operation was significantly lower than 8.7+/-4.2 pg/ml of Group C. We conclude that plasma IL-6 and IL-8 response to surgical trauma is inhibited in chronic depressed patients. The IL-6 response to surgical trauma is depending on the clinical state of depression.

The effect of oophorectomy and estrogen replacement therapy on Doppler derived parameters of aortic flow

OBJECTIVES

The immediate consequences of surgical castration and estrogen replacement therapy (ERT) on left ventricular systolic performance as assessed by Doppler-derived parameters of aortic flow were examined.

METHODS

A follow up study comprising two groups: eight premenopausal women who underwent hysterectomy and bilateral oophorectomy and started ERT 1 week after surgery - the study group, and a control group consisted of eight premenopausal women who did not start ERT following hysterectomy. Doppler echocardiography was performed before surgery, 1 week and 1 month post surgery.

RESULTS

In both groups significant increase in heart rate was observed after 1 week, remaining high after 1 month in the control group only. The early post-operative period in all women was characterized by an increase in aortic flow velocity, but was statistically significant in the study group only. After initiation of ERT a significant decrease in peak flow velocity (PFV) and mean acceleration (MA) was recorded.

CONCLUSIONS

Changes in estradiol level may be associated with alterations in left ventricular function. The initial and acute effect of estrogen on the heart muscle after surgical castration is towards a decrease in Doppler-derived parameters of aortic flow. Whether these effects represent a depression of left ventricular function, or alternatively, reflect peripheral vasculature reactivity, requires further evaluation.

Blood levels of corticosteroid-binding globulin, total cortisol and unbound cortisol in patients undergoing coronary artery bypass grafting surgery with cardiopulmonary bypass

Previous studies have demonstrated a persistent rise in serum cortisol concentrations after cardiac surgery. To further investigate this finding and to evaluate the effect of hemodilution that occurs with the onset of cardiopulmonary bypass (CPB), concentrations of cortisol-binding globulin (CBG), total and unbound cortisol, and packed cell volume (PCV) were studied in 28 patients undergoing coronary artery bypass graft surgery. All patients received a standardized general anesthetic using a balanced technique with sufentanil, isoflurane, and midazolam. Blood was collected preoperatively, intraoperatively during CPB, and postoperatively in the evenings on the day of surgery and on the first and second postoperative day. Cortisol and CBG concentrations were measured by radioimmunoassay and were used to calculate the fraction of unbound cortisol. Serum CBG and cortisol concentrations corrected for hemodilution were significantly higher than non-corrected values. Perioperatively, CBG measurements were significantly intercorrelated. Intraoperatively, total and unbound cortisol concentrations were not significantly increased compared to preoperative values. Postoperatively up to the end of the study period serum concentrations of total and unbound cortisol were significantly increased compared to baseline values. Our results suggest that hemodilution occurs in all patients during cardiac surgery and continues up to the second postoperative day. This may lead to an underestimation of serum cortisol and CBG concentrations in patients undergoing heart surgery with CPB. Intraoperatively, concentrations of total and unbound cortisol were not significantly elevated. The postoperative rise in serum total cortisol concentration was accompanied by an increase in unbound cortisol concentration. The postoperative increase of unbound cortisol concentrations in patients undergoing cardiac surgery with CPB was largely due to an increase in cortisol secretion.

Inhibition of the cortisol response to surgical stress in chronically depressed patients

STUDY OBJECTIVE

To evaluate whether the pituitary-adrenal and catecholamine response to surgical stress is modified in chronically depressed patients.

DESIGN

Prospective, controlled study.

PATIENTS

25 ASA physical status I and II depressed patients taking chronic antidepressant therapy and 25 control patients undergoing orthopedic surgery of the extremities.

INTERVENTIONS

All patients received anesthesia induction with thiopental 5 mg/kg and suxamethonium 1 mg/kg intravenously (IV) and were maintained with 1.5% to 2.0% isoflurane in nitrous oxide (70%) and oxygen (30%).

MEASUREMENTS AND MAIN RESULTS

Plasma cortisol concentration (27.7 +/- 3.6 microg/dL) in chronic depressed patients at 60 minutes after the skin incision was not significantly higher than that (23.9 +/- 2.7 microg/dL) before the induction, although plasma cortisol concentration in the control group significantly increased. Plasma norepinephrine concentration at 60 min after the skin incision in depressed patients with more symptoms of depression was significantly higher than that of patients with less symptoms of depression.

CONCLUSION

The cortisol response to surgical stress in depressed patients was inhibited and norepinephrine response to surgical stress was increased in depressed patients with more symptoms of depression.

Role of xanthine oxidase in small bowel mucosal dysfunction after surgical stress

BACKGROUND

The small intestine is highly susceptible to surgical stress even at remote locations. An earlier study using a rat model indicated that oxidative stress plays an important role in this process. The enzyme xanthine oxidase is an important source of free radicals in the small intestine. The role of this enzyme in intestinal damage after surgical stress was examined.

METHODS

Rats pretreated with xanthine oxidase inhibitors were subjected to surgical stress by opening the abdomen and handling the intestine, as done during laparotomy. Enterocytes at various stages of differentiation were isolated and the protection offered by xanthine oxidase inhibitors against damage due to surgical stress was determined and compared with normal controls. Protection against ultrastructural changes to the mucosa, as well as mitochondrial function was examined.

RESULTS

Surgical stress affected both the villus as well as crypt cells, causing increased superoxide generation, accompanied by increased activity of xanthine oxidase. Xanthine oxidase inhibitors ameliorated the increased superoxide generation, and protected against mitochondrial damage and ultrastructural changes in the intestine.

CONCLUSION

Surgical stress affects both the villus and crypt cell populations in the small intestine. The enzyme xanthine oxidase maybe an important mediator of surgical stress in the intestine.

[[Hypnosedation, a new method of anesthesia for cervical endocrine surgery. Prospective randomized study]

Retrospective studies have confirmed the feasibility and safety of thyroid and parathyroid procedures performed under hypnoanesthesia (hypnosis, local anesthesia and minimal conscious sedation) as sole method of anesthesia. This very effective technique seems to provide physiological, psychological and economic benefits for the patient.

STUDY AIM

To assess, by means of a prospective randomized study, the advantages of hypnosedation as an alternative to general anesthesia in terms of clinical and laboratory parameters.

PATIENTS AND METHODS

Twenty patients operated under hypnoanesthesia were compared to 20 patients operated under conventional anesthesia. The two groups were compared in terms of inflammatory, neuroendocrine, hemodynamic and immunologic parameters and postoperative course (pain, fatigue, muscle strength and stress).

RESULTS

No clinical or demographic differences were observed between the two groups. Operative times, bleeding, weight of specimens, and surgical comfort were similar. Significant differences in terms of inflammatory response and hemodynamic parameters were observed in favor of hypnoanesthesia. Neuroendocrine and immunological parameters were similar. Patients of the hypnoanesthesia group had significantly less postoperative pain. Postoperative fatigue syndrome and convalescence were significantly improved in these patients.

CONCLUSION

This study confirms that, in our hands, hypnosedation presents real advantages over general anesthesia, in patients undergoing thyroid surgery.

The immune-endocrine interaction varies with the duration of the inflammatory process in cardiac surgery patients

The present study investigated the perioperative course of cytokine release and hypothalamic-pituitary-adrenal (HPA) axis activation in relation to the duration of the inflammatory response in cardiac surgery patients. Twelve male patients scheduled for elective coronary artery bypass grafting surgery with cardiopulmonary bypass and general anaesthesia were divided into two study groups: group 1 (n=6) underwent surgery at 13.00 h+/-30 min, group 2 (n=6) at 08.30 h+/-50 min. Blood samples were collected preoperatively and up to the first postoperative day. Postoperatively, on the day of surgery, serum concentrations of the proinflammatory cytokines interleukin (IL)-6, IL-1beta and tumour necrosis factor (TNF)-alpha were not significantly different between the two groups, while blood concentrations of cortisol, adrenocorticotrophic hormone (ACTH) and beta-endorphin in group 2 patients were significantly higher than in group 1 patients. Postoperatively, on the day of surgery, ACTH and cortisol concentrations in group 1 patients were positively correlated to the blood concentrations of IL-1beta, IL-6 and TNF-alpha. By contrast, group 2 patients showed no significant relationship between cytokine release and activation of HPA axis at this time. Our results suggest that in patients undergoing cardiac surgery, the cytokine response is initiated before the HPA axis is fully activated. In the early postoperative period, cytokines appear to be involved in the activation of the HPA axis, while in the later postoperative period, high cortisol concentrations may inhibit the release of IL-6.

Heat shock response reduces mortality after severe experimental burns

The heat shock response has imparted protective effects in animal models of septic shock and endotoxemia. This study has tested the hypothesis that it could be protective in experimental burns. One hundred and fifteen adult male Fischer rats were randomly divided into four groups. Rats in the first group (n = 12) were anesthetized and shaved. In the second group (n = 15) rats were anesthetized and heated in a 45 degrees C water bath. In the third group (n = 44), rats were anesthetized, shaved and submitted to 26-30% body surface third-degree burns using a brass bar. In the fourth group (n = 44), rats were anesthetized, heated and, 1 day after, they were burnt. Mortality rates were measured at 3, 7, 15 and 25 days. Liver and lung samples were collected from all groups for heat-shock protein 70 detection. Heat-shock protein 70 was positive in heated animals. No animals died in the first or second group. Heated and burnt animals showed significantly decreased mortality at days 3 (p < 0.05, Fischer's exact test) and at days 7, 15 and 25 (p < 0.01) after burns, when compared to unheated burnt animals. In conclusion, eliciting the heat-shock response significantly reduced mortality rates in this model of experimental burns.