The Correlation Between ApoM And Severity Of Bacterial Infection And Probable Regulatory Mechanism

ObjectiveTo explore the correlation between serum apolipoprotein M levels and the severity of bacterial infection in patients. Meanwhile, the probable regulatory mechanism of apoM in inflammation was investigated.Methods1. Serum samples from infection without SIRS (n=90), sepsis (n=90), severe sepsis (n=90), severe sepsis and shock(n=90) as well as healthy control without infection and fever (n=90)were collected. The levels of lipids, apo M, Hs-CRP and PCT were analyzed. The variations of apoM and other aforementioned items concentrations in different groups were observed, meanwhile the correlations between them and PCT were analyzed separately2. HepG2cells were treated with DMEM (control), DMEM+100ng/ml LPS, DMEM+100ng/ml LPS+50μmol/L PDTC separately. The mRNA and protein levels of apoM, PCT and P65were determined by real-time PCR and western blot, respectively. Meanwhile, the location and fluorescence intensity of apoM and P65were observed by immunofluorescence assay.Results1. Significantly decreased values of apoM in sepsis, severe sepsis and severe sepsis and shock were observed either comparing with the healthy control or the infection without SIRS groups(all the P values were less than0.05). Moreover, the apoM value in the group of severe sepsis and shock was dramatically lower than that in sepsis and severe sepsis groups (all the P values were less than0.05). The serum level of apoM correlated negatively to PCT in patients with bacterial infection(r=-0.463, P<0.05). The area under the curve (AUC) of Receiver Operating Characteristic (ROC) of apoM in diagnosing bacterial infection was0.773(95%CI:0.709-0.836)2. LPS increased PCT and P65mRNA and protein levels while decreased apoM levels. Blocking the NF-KB pathway with PDTC, the alternation of PCT, P65and apoM displayed a similar trend but not as pronounced as LPS stimuli.3. The fluorescence of apoM was located in cytoplasm and attenuated with LPS stimuli. When blocking the the NF-KB pathway with PDTC, the apoM fluorescence enhanced compared with cells exposed to LPS. Compared with apoM, P65demonstrated a reverse variation and mainly located in cytoblast. Conclusion1. During bacterial infection, the level of apoM was decreasd significantly with the severity of inflammation which suggests that apoM may be a useful marker for assessing the severity of inflammation.2. The variations of apoM in infection may be regulated by P65which is a key factor of NF-KB pathway.There are19figures,12tables and57references in this article.