Trametinib, a novel MEK kinase inhibitor, suppresses lipopolysaccharide-induced tumor necrosis factor (TNF)-α production and endotoxin shock.

Lipopolysaccharide (LPS), one of the most prominent pathogen-associated molecular patterns (PAMPs), activates macrophages, causing release of toxic cytokines (i.e. tumor necrosis factor (TNF)-α) that may provoke inflammation and endotoxin shock. Here, we tested the potential role of trametinib, a novel and highly potent MAPK/ERK kinase (MEK) inhibitor, against LPS-induced TNF-α response in monocytes, and analyzed the underlying mechanisms. We showed that trametinib, at nM concentrations, dramatically inhibited LPS-induced TNF-α mRNA expression and protein secretion in transformed (RAW 264.7 cells) and primary murine macrophages. In ex-vivo cultured human peripheral blood mononuclear cells (PBMCs), this MEK inhibitor similarly suppressed TNF-α production by LPS. For the mechanism study, we found that trametinib blocked LPS-induced MEK-ERK activation in above monocytes, which accounted for the defective TNF-α response. Macrophages or PBMCs treated with a traditional MEK inhibitor PD98059 or infected with MEK1/2-shRNA lentivirus exhibited a similar defect as trametinib, and nullified the activity of trametinib. On the other hand, introducing a constitutively-active (CA) ERK1 restored TNF-α production by LPS in the presence of trametinib. In vivo, mice administrated with trametinib produced low levels of TNF-α after LPS stimulation, and these mice were protected from LPS-induced endotoxin shock. Together, these results show that trametinib inhibits LPS-induced TNF-α expression and endotoxin shock probably through blocking MEK-ERK signaling.

Effects of hypothermia on the liver in a swine model of cardiopulmonary resuscitation / 世界急诊医学杂志（英文）

@#BACKGROUND: The study aimed to explore the effects of hypothermia state induced by 4 oC normal saline (NS) on liver biochemistry, enzymology and morphology after restoration of spontaneous circulation (ROSC) by cardiopulmonary resuscitation (CPR) in swine. METHODS: After 4 minutes of ventricular fibrillation (VF), standard CPR was carried out. Then the survivors were divided into two groups: low temperature group and normal temperature group. The low temperature (LT) group (n=5) received continuously 4 oC NS at the speed of 1.33 mL/kg per minute for 22 minutes, then at the speed lowering to 10 mL/kg per hour. The normal temperature (NT) group (n=5) received NS with normal room temperature at the same speed of the LT group. Hemodynamic status and oxygen metabolism were monitored and the levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were measured in blood samples obtained at baseline and at 10 minutes, 2 hours and 4 hours after ROSC. At 24 hours after ROSC, the animals were killed and the liver was removed to determine the Na+-K+-ATPase and Ca2+-ATPase enzyme activities and histological changes under a light or electron microscope. RESULTS: Core temperature was decreased in the LT group (P<0.05), while HR, MAP and CPP were not significantly decreased (P>0.05) compared with the NT group (P>0.05). The oxygen extraction ratio was lower in the LT group than in the NT group (P<0.05). The serum levels of ALT, AST and LDH increased in both groups but not significantly in the LT group. The enzyme activity of liver ATP was much higher in the LT group (Na+-K+-ATP enzyme: 8.64±3.32 U vs. 3.28±0.71 U; Ca2+-ATP enzyme: 10.92±2.12 U vs. 2.75±0.78 U, P<0.05). The LT group showed less cellular edema, inflammation and few damaged mitochondria as compared with the NT group. CONCLUSION: These data suggested that infusing 4 oC NS continuously after ROSC could quickly lower the core body temperature, while maintaining a stable hemodynamic state and balancing oxygen metabolism, which protect the liver in terms of biochemistry, enzymology and histology after CPR.

Misdiagnosis of aortic dissection: experience of 361 patients.

Aortic dissection (AD) is a life-threatening condition that requires immediate diagnosis and surgical correction. Patients with acute AD usually present clinically with an insignificant medical history, leading to a high probability of misdiagnosis. The aim of the present study was to investigate the number of misdiagnoses of patients with AD in order to understand this problem and to avoid future misdiagnosis in the emergency department. Clinical data from 361 patients with AD admitted between January 2003 and June 2008 were reviewed as part of a retrospective chart review. Diagnosis of AD was made using either chest x-ray, computed tomography, magnetic resonance imaging, or angiography. Fifty-one patients had an initial misdiagnosis (14.1%), later found to have experienced AD. The condition may clinically present in a varied number of manifestations, including syncope, chest pain, abdominal pain, back pain, acute congestive heart failure, or alternatively with minimal symptoms. Persons of any age can experience an AD, with key clinical manifestations of pain. Echocardiography can be used for primary examination of patients with suspected AD; however, a definite diagnosis is usually made using computed tomographic or magnetic resonance angiography. Care should be taken, particularly in the emergency department, to maintain a level of suspicion for AD diagnosis in order to avoid the potential for misdiagnosis.

Association of genetic variants in the IRAK-4 gene with susceptibility to severe sepsis / 世界急诊医学杂志（英文）

BACKGROUND: The association of genetic variation in the IRAK-1 gene with sepsis outcome has been proved. However, few studies have addressed the impact of the IRAK-4 gene variants on sepsis risk. This study aimed to determine whether the polymorphisms in the IRAK-4 gene are associated with susceptibility to and prognosis of severe sepsis in the Chinese Han ethnic population.METHODS: In this case-control study, 192 patients with severe sepsis hospitalized in the emergency department of Zhongshan Hospital from February 2006 to December 2009 and 192 healthy volunteers were enrolled. Exclusion criteria included metastatic tumors, autoimmune diseases, AIDS or treatment with immunosuppressive drugs. This study was approved by the ethical committee of Zhongshan Hospital, Fudan University. Sepsis patients were divided into a survival group (n=124) and a non-survival group (n=68) according to the 30-day mortality. Primer 3 software was used to design PCR and sequencing primers. Genomic DNA was extracted from peripheral blood mononuclear cells. Seven tagSNPs in IRAK-4 were selected according to the data of the Chinese Han population in Beijing from the Hapmap project and genotyped by direct sequencing. The chi-square test was used to evaluate the differences in genotype and allele frequencies between the two groups.RESULTS: The distributions of all tagSNPs were consistent with Hardy-Weinberg equilibrium. The allele and genotype frequencies of rs4251545 (G/A) were significantly different between the severe sepsis and healthy control groups (P=0.015, P=0.035, respectively). Carriers of the rs4251545A had a higher risk for severe sepsis compared with carriers of the rs4251545G (OR=1.69, 95％ CI: 1.10-2.58). The allele and genotype frequencies of all SNPs were not significantly different between the survival group and non-survival group.CONCLUSION: These findings indicate that the variants in IRAK-4 are significantly associated with susceptibility to severe sepsis in the Chinese Han ethnic population.