Critical illness and bone metabolism: where are we now and what is next?

Critical illness refers to the clinical signs of severe, variable and life-threatening critical conditions, often accompanied by insufficiency or failure of one or more organs. Bone health of critically ill patients is severely affected during and after ICU admission. Therefore, clinical work should focus on ICU-related bone loss, and early development and implementation of related prevention and treatment strategies: optimized and personalized nutritional support (high-quality protein, trace elements and intestinal prebiotics) and appropriate physiotherapy and muscle training should be implemented as early as possible after ICU admission and discharge. At the same time, the drug regulates excessive metabolism and resists osteoporosis.

Protective effects of combined treatment with mild hypothermia and edaravone against cerebral ischemia/reperfusion injury via oxidative stress and Nrf2 pathway regulation.

Mild hypothermia (MH) and edaravone (EDA) exert neuroprotective effects against cerebral ischemia/reperfusion (I/R) injury through activation of the nuclear factor erythroid 2­related factor 2 (Nrf2) pathway. However, whether MH and EDA exert synergistic effects against cerebral I/R injury remains unknown. The aim of the present study was to investigate the effects and mechanism of action of MH in combination with EDA in cerebral I/R injury. A rat cerebral I/R injury model was constructed by middle cerebral artery occlusion (MCAO) followed by reperfusion, and the mice were treated by MH, EDA or the inhibitor of the Nrf2 signaling pathway brusatol (Bru). It was observed that mice treated by MCAO had higher neurological deficit scores and oxidative stress levels, and low spatial learning and memory capacity; moreover, the CA1 region of the hippocampi of the mice exhibited reduced neuronal density and viability, and reduced mitochondrial dysfunction. However, MH in combination with EDA reversed the effects of MCAO, which were blocked by Bru injection. The levels of glutathione (GSH), GSH peroxidase, catalase and superoxide dismutase in rat ischemic hemisphere tissues were reduced by Bru. Western blotting demonstrated that the combined treatment with MH and EDA promoted the nuclear localization of Nrf2, and increased the levels of NAD(P)H quinone oxidoreductase and heme oxygenase (HO)­1. In conclusion, MH combined with EDA exerted synergistic neuroprotective effects against cerebral I/R injury involving changes in the Nrf2/HO­1 pathway.

Neuroprotective effects of midazolam on focal cerebral ischemia in rats through anti­apoptotic mechanisms.

Stroke is a cerebrovascular circulatory disorder and its high mortality rate represents a prominent threat to human health. Subsequent apoptosis and cytotoxicity are the main causes underlying the poor prognosis. Midazolam (MDZ) is a benzodiazepine drug that is clinically used during surgical procedures and for the treatment of insomnia, with a potential ability to treat stroke. The protective effect of MDZ was investigated on glutamate­induced cortical neuronal injuries in vitro and transient middle cerebral artery occlusion (tMCAO) rat models in vivo. Western blot analysis and semi quantitative RT­PCR were used to evaluate the potential underlying mechanisms. In vitro studies revealed that MDZ regulated apoptosis­associated gene expression and inhibited lactate dehydrogenase (LDH) release, protecting against neuronal damage. In vivo studies revealed that MDZ reduced LDH­induced neuronal damage by reducing LDH release from the peripheral blood, and brain tissue staining revealed that MDZ protected neurons during tMCAO. MDZ protected neurons under an ischemic environment by inhibiting LDH release and regulating apoptosis­associated gene expression to reduce cytotoxicity and apoptosis. These results provide a reliable basis for further studies on the effect of MDZ, to improve the prognosis of cerebral infarction.

Propofol attenuates inflammatory damage on neurons following cerebral infarction by inhibiting excessive activation of microglia.

The overall incidence rate of stroke is increasing worldwide. Inflammatory damage following a stroke is a leading cause for the poor prognosis and high disability rate observed in stroke patients. Microglia are considered to be the main causative agents of inflammatory injury following cerebral infarction, as they secrete various inflammatory cytokines and cytotoxic factors. The aim of the present study was to identify novel methods for attenuating inflammatory injury and improving the prognosis of stroke patients. Lipopolysaccharide-stimulated microglia were treated using propofol in vitro and a transient middle cerebral artery occlusion/reperfusion model was constructed in rats. Expression of cytotoxic factors, microglia proliferation and the neuroprotective effects of propofol were measured in vitro and in vivo. The in vitro studies demonstrated that propofol inhibits the expression of multiple cytotoxic factors, prevents structural changes to cytoskeletal proteins, and suppresses microglial migration via the adenosineA2b receptors. The results of the in vivo experiments revealed that propofol inhibits the abnormal proliferation of microglia, as well as reduces the expression levels of interleukin (IL)-6, IL-1ß, tumor necrosis factor α, and the cytotoxic factor nitric oxide through the A2b receptor. In conclusion, propofol inhibited the excessive activation of microglia through the A2b receptor and attenuated the inflammatory injury following cerebral infarction. The current study may provide a reliable basis for further clinical studies on propofol and its putative role in improving the prognosis of patients with cerebral infarction.

Prediction about severity and outcome of sepsis by pro-atrial natriuretic peptide and pro-adrenomedullin.

OBJECTIVE: Measurement of biomarkers is a potential approach to early prediction of the risk of mortality in patients with sepsis. The aim of the present study was to evaluate the prognostic value of pro-atrial natriuretic peptide (pro-ANP) and pro-adrenomedullin (pro-ADM) levels in a cohort of medical intensive care patients and to compare it with that of other known biomarkers and physiological scores. METHODS: Blood samples of 51 consecutive critically ill patients admitted to the intensive care unit and 53 age-matched healthy control people were evaluated in this prospective study. The prognostic value of pro-ANP and pro-ADM levels was compared with that of acute physiology and chronic health evaluation (APACHE) II scores and various biomarkers such as C-reactive protein, interleukin-6 and procalcitonin. Pro-ANP and pro-ADM were detected by a new sandwich immunoassay. RESULTS: On admission, 25 patients had systemic inflammatory response syndrome (SIRS), 12 sepsis, 9 severe sepsis and 5 septic shock. At that time, the median levels (ng/ml) of pro-ANP and pro-ADM were 87.22 and 0.34 respectively in patients with SIRS, 1533.30 and 2.23 in those with sepsis, 1098.73 and 4.57 in those with severe sepsis, and 1933.94 and 8.21 in those with septic shock. With the increasing severity of disease, the levels of pro-ANP and pro-ADM were gradually increased. On admission, the circulating levels of pro-ANP and pro-ADM in patients with sepsis, severe sepsis, or septic shock were significantly higher in non-survivors than in survivors (P less than 0.05). In a receiver operating characteristic curve analysis for the survival of patients with sepsis, the areas under the curve (AUCs) for pro-ANP and pro-ADM were 0.89 and 0.87 respectively, which was similar to the AUCs for procalcitonin and APACHE II scores. CONCLUSION: Pro-ANP and pro-ADM are valuable biomarkers for prediction of severity of septic patients.

[The study on pro-adrenomedullin as a new biomarker in sepsis prognosis and risk stratification].

OBJECTIVE: To assess the clinical value of pro-adrenomedullin (pro-ADM) in the prognosis and risk stratification in sepsis. METHODS: Fifty-one critically ill patients admitted to the intensive care unit (ICU) were prospectively stratified into four groups according to internationally recognized criteria: systemic inflammatory response syndrome (SIRS, 25 cases), sepsis (12 cases), severe sepsis (9 cases) and septic shock (5 cases). The levels of plasma pro-ADM was determined in every patient using a new sandwich immunoassay, and compared with procalcitonin (PCT), C-reactive protein (CRP) and interleukin-6 (IL-6), and the acute physiology and chronic health evaluation II (APACHE II) score. RESULTS: (1) Median pro-ADM concentration was 0.34 microg/L for SIRS, 2.23 microg/L for sepsis, 4.57 microg/L for severe sepsis and 8.21 microg/L for septic shock. The plasma concentration of pro-ADM exhibited a gradual increase, and the median pro-ADM value was highest in the septic shock group (all P<0.05). (2) Compared with the other biomarkers, in the sepsis, severe sepsis and septic shock groups, the plasma concentration of pro-ADM and APACHE II score in the non-survivors was significantly higher than in the survivors (pro-ADM: 2.01 microg/L vs. 9.75 microg/L, APACHE II score: 23.44 scores vs. 38.21 scores, both P<0.05). (3) By the receiver operating characteristic (ROC) curve plot analysis of pro-ADM in sepsis, the area under the ROC curve for pro-ADM (0.87) in survivors was similar to the area under the ROC curve for PCT (0.81) and APACHE II score (0.81), and was significantly higher than the area under the ROC curve for CRP (0.53) and IL-6 (0.71). CONCLUSION: The measurement of pro-ADM is a new and useful marker in sepsis prognosis and risk stratification.