Decreased synthesis and increased degradation of MyHCs contribute to ICU-acquired muscle wasting. The rates and time frames suggest that pathogenesis of muscle failure is initiated very early during critical illness. The persisting reduction of MyHC suggests that sustained treatment is required.

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ObjectivesSystemic inflammation is a major risk factor for critical-illness myopathy (CIM) but its pathogenic role in muscle is uncertain. We observed that interleukin 6 (IL-6) and serum amyloid A1 (SAA1) expression was upregulated in muscle of critically ill patients. To test the relevance of these responses we assessed inflammation and acute-phase response at early and late time points in muscle of patients at risk for CIM.DesignProspective observational clinical study and prospective animal trial.SettingTwo intensive care units (ICU) and research laboratory.Patients/Subjects33 patients with Sequential Organ Failure Assessment scores ≥8 on 3 consecutive days within 5 days in ICU were investigated. A subgroup analysis of 12 patients with, and 18 patients without CIM (non-CIM) was performed. Two consecutive biopsies from vastus lateralis were obtained at median days 5 and 15, early and late time points. Controls were 5 healthy subjects undergoing elective orthopedic surgery. A septic mouse model and cultured myoblasts were used for mechanistic analyses.Measurements and Main ResultsEarly SAA1 expression was significantly higher in skeletal muscle of CIM compared to non-CIM patients. Immunohistochemistry showed SAA1 accumulations in muscle of CIM patients at the early time point, which resolved later. SAA1 expression was induced by IL-6 and tumor necrosis factor-alpha in human and mouse myocytes in vitro. Inflammation-induced muscular SAA1 accumulation was reproduced in a sepsis mouse model.ConclusionsSkeletal muscle contributes to general inflammation and acute-phase response in CIM patients. Muscular SAA1 could be important for CIM pathogenesis.Trial RegistrationISRCTN77569430.

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BACKGROUND. Inflammation and perturbation of the hypothalamic‐pituitary‐adrenal (HPA) axis function appears to play a putative role in the etiology of depression. Patients with metastatic cancer demonstrate elevated prevalence rates for depression. The objective of the current study was to illustrate the efficacy of interleukin‐6 (IL‐6) and HPA axis function as adjuncts to support the diagnosis of depression in cancer patients. METHODS. Plasma concentrations of IL‐6 and cortisol were measured in 114 cancer patients with and without depression. The relative diurnal variation of cortisol (cortisol VAR), expressed as a percentage, was calculated. Receiver operating characteristics analysis was performed. RESULTS. Depression was associated with increased plasma concentrations of IL‐6 (18.7 pg/mL vs. 2.7 pg/mL; P < .001) and higher cortisol concentrations at 8 AM and 8 PM. The relative cortisol VAR (11.7% vs. 60.6%, respectively; P < .001) was found to be decreased in cancer patients with depression, indicating a disturbed circadian function of the HPA axis. As a biomarker of depression, IL‐6 yielded at a cutoff value of 10.6 pg/mL, a sensitivity of 79%, and a specificity of 87% (area under the curve [AUC] = 0.86; 95% confidence interval [95% CI], 0.78–0.94), whereas cortisol VAR demonstrated a sensitivity of 81% and a specificity of 88% (AUC = 0.85; 95% CI, 0.74–0.97) at a cutoff value of 33.5%. CONCLUSIONS. Depression is associated with increased plasma IL‐6 concentrations in patients with cancer. These patients demonstrate a dysfunction of the HPA‐axis, characterized by a decreased diurnal variation of cortisol. The high sensitivity and specificity of these parameters biomarkers of depression make IL‐6 and cortisol VAR helpful tools in the diagnosis of depression in patients with cancer. Cancer 2006. © 2006 American Cancer Society.

Early electrophysiological testing predicts long-term outcome in ICU survivors. CIM has a significantly better prognosis than CIM/CIP.

Acute hypoxia increases pulmonary arterial pressure and vascular resistance. Previous studies in isolated smooth muscle and perfused lungs have shown that carbonic anhydrase (CA) inhibition reduces the speed and magnitude of hypoxic pulmonary vasoconstriction (HPV). We studied whether CA inhibition by acetazolamide (Acz) is able to prevent HPV in the unanesthetized animal. Ten chronically tracheotomized, conscious dogs were investigated in three protocols. In all protocols, the dogs breathed 21% O(2) for the first hour and then 8 or 10% O(2) for the next 4 h spontaneously via a ventilator circuit. The protocols were as follows: protocol 1: controls given no Acz, inspired O(2) fraction (Fi(O(2))) = 0.10; protocol 2: Acz infused intravenously (250-mg bolus, followed by 167 microg.kg(-1).min(-1) continuously), Fi(O(2)) = 0.10; protocol 3: Acz given as above, but with Fi(O(2)) reduced to 0.08 to match the arterial Po(2) (Pa(O(2))) observed during hypoxia in controls. Pa(O(2)) was 37 Torr during hypoxia in controls, mean pulmonary arterial pressure increased from 17 +/- 1 to 23 +/- 1 mmHg, and pulmonary vascular resistance increased from 464 +/- 26 to 679 +/- 40 dyn.s(-1).cm(-5) (P < 0.05). In both Acz groups, mean pulmonary arterial pressure was 15 +/- 1 mmHg, and pulmonary vascular resistance ranged between 420 and 440 dyn.s(-1).cm(-5). These values did not change during hypoxia. In dogs given Acz at 10% O(2), the arterial Pa(O(2)) was 50 Torr owing to hyperventilation, whereas in those breathing 8% O(2) the Pa(O(2)) was 37 Torr, equivalent to controls. In conclusion, Acz prevents HPV in conscious spontaneously breathing dogs. The effect is not due to Acz-induced hyperventilation and higher alveolar Po(2), nor to changes in plasma endothelin-1, angiotensin-II, or potassium, and HPV suppression occurs despite the systemic acidosis with CA inhibition.

Depression and anxiety are the core disorders causing emotional distress in patients (pts) with metastatic breast cancer. The aim of our study was to screen metastatic breast cancer outpatients for anxiety and depression, and to investigate the influence of age, Karnofsky Performance Status (KPS), cancer activity, and inflammation as represented by IL-6 levels on these two mood disorders. Pts treated with chemotherapy for metastatic breast cancer (n = 70) were assessed using the Hospital Anxiety and Depression Scale (HADS) for symptoms (scores 0-21) and caseness (score ≥11) of clinical depression and anxiety. Blood samples for IL-6 concentrations were collected at 10:00 a.m. A total of 22 (31.4 %) pts were diagnosed with caseness of clinical depression and 23 (32.9 %) pts with clinical anxiety, while 12 pts were diagnosed positive for both mood disorders. Depression and anxiety were positively but moderately correlated (Spearman's r (2) = 0.24, p < 0.001). IL-6 was significantly correlated with symptoms of depression (r (2) = 0.42, p < 0.001) and to a lesser extent to symptoms of anxiety (r (2) = 0.16, p = 0.001). In addition, IL-6 was positively associated with tumor progression (p < 0.001). Multiple linear regression analysis showed that tumor progression (standardized b = 0.226, p = 0.047), symptoms of anxiety (b = 0.292, p = 0.016), and IL-6 (b = 0.314, p = 0.007) were independently associated with clinical depression, whereas anxiety was linked to tumor progression (b = 0.238, p = 0.030), symptoms of depression (b = 0.407, p < 0.001) and age (b = -0.381, p < 0.001), but not to IL-6 (b = 0.168, p = 0.134). Even though a positive correlation between depression and anxiety exists, clinical parameters like age, cancer activity, KPS, and IL-6 do influence depression and anxiety differently. Unlike clinical depression, anxiety is not associated with increased IL-6 levels, however, shows a reciprocal correlation with age.