Hypothermia treatment ameliorated cyclin-dependent kinase 5-mediated inflammation in ischemic stroke and improved outcomes in ischemic stroke patients

OBJECTIVES: The inflammatory response is a key mechanism of neuronal damage and loss during acute ischemic stroke. Hypothermia has shown promise as a treatment for ischemic stroke. In this study, we investigated the molecular signaling pathways in ischemic stroke after hypothermia treatment. METHODS: Cyclin-dependent kinase 5 (CDK5) was overexpressed or silenced in cultured cells. Nuclear transcription factor-κB (NF-κB) activity was assessed by measurement of the luciferase reporter gene. An ischemic stroke model was established in Sprague-Dawley (SD) rats using the suture-occluded method. Animals were assigned to three groups: sham operation control, ischemic stroke, and ischemic stroke + hypothermia treatment groups. Interleukin 1β (IL-1β) levels in the culture supernatant and blood samples were assessed by ELISA. Protein expression was measured by Western blotting. RESULTS: In HEK293 cells and primary cortical neuronal cultures exposed to hypothermia, CDK5 overexpression was associated with increased IL-1β, caspase 1, and NF-κB levels. In both a murine model of stroke and in patients, increased IL-1β levels were observed after stroke, and hypothermia treatment was associated with lower IL-1β levels. Furthermore, hypothermia-treated patients showed significant improvement in neurophysiological functional outcome. CONCLUSIONS: Overall, hypothermia offers clinical benefit, most likely through its effects on the inflammatory response.

Enzyme Detection and Metabolic Process Tracking of Ethanol Fermentation by a Natural Alginate Fermentation Strain

ABSTRACT Alginate is a major component of brown algae, but it cannot be utilized for ethanol fermentation by industrial microorganisms. A natural alginate degrading and ethanol producing strain was obtained in our previous research. However, the research on the ethanol metabolism process of the natural alginate fermentation strain is lacked. In this research, the key enzyme and metabolic process of ethanol fermentation were studied. Three kinds of key enzyme including alginate lyase, pyruvate dehydrogenase and ethanol dehydrogenase were determined. The enzyme activity in the metabolic process was relatively high at 60-96 h which was the most important period during the fermentation. Meanwhile the concentration change of the important substances including soluble sugar, reducing sugar, acidity, pyruvic acid and ethanol were tracked and analyzed. Total soluble sugar and reducing sugar change tendency during the fermentation was similar. In the whole fermentation process, the fermentation broth was acidic. The value of pyruvic acid content reached highest at 72 h. During 48-96 h, the growth of ethanol concentration was very obvious. The alginate metabolic process in natural alginate fermentation strain was to generate extracellular alginate lyase to degrade alginate to produce reducing sugar, and then some intermediate metabolites formed such as pyruvic acid. Finally under the effect of pyruvate dehydrogenase and ethanol dehydrogenase, ethanol was produced.