| Background:Mycoplasma pneumoniae pneumonia(MPP)is a common community-acquired pneumonia in children.The incidence of Severe mycoplasma pneumoniae pneumonia(SMPP)has been increasing in recent years.Phospholipids account for 90%of the lipid components of lung surfactants,which are important structural components of cell membranes,precursors of many inflammatory substances,and the main nutrients required for the survival of mycoplasma.With the development of metabonomics,foreign scholars have found that the occurrence and development of pneumonia is related to phospholipids.In China,there are few clinical studies on relationship of mycoplasma pneumoniae pneumonia and phospholipids in children.Objective:1.Analyze the difference of phospholipids levels in serum with MPP and evaluate its predictive efficiency for SMPP;2.The metabolomic differences between MPP and normal children were compared to analyze the influence of metabolic changes on the pathophysiological process of MPP,and to evaluate the components of phospholipid on predictive efficiency for SMPP.Methods:1.Clinical data of 319 hospitalized children with MPP were retrospectively studied to compare the difference of phospholipid levels between MPP and SMPP,and to analyze the predictive efficiency of phospholipid in SMPP and co-infection;2.A total of 50 children with mycoplasma pneumonia as the case group were recruited from and meanwhile 50 age-and gender-matched heathy children were selected and formed the control group.Clinical information and serum samples were collected within 24 hours after admission.Serum metabolites were quantified by using the untargeted ultra-high performance liquid chromatography/tandem mass spectrometry(UPLC-MS/MS)technique.Unsupervised principle component analysis and(orthogonal)partial least-squares-discriminant analysis were employed to identify differential metabolites.MBRole software was used for pathway enrichment analysis.The predictive efficiency was evaluated by the receiver operating curve.Results:1.There were 45 boys and 46 girls in SMPP group with an average age of 3.71±3.73 years.There were 131 boys and 97 girls in mild MPP with an average age of 3.98±3.87 years old.There was no significant difference in gender and age between groups.Phospholipid in SMPP group was significantly decreased(P<0.05).Decrease of phospholipids was a risk factor for SMPP(OR=0.359,P<0.05).The area under the curve(AUC)was 0.673(sensitivity 0.747,specificity 0.491),and the cut-off value was 1.79mmol/L(P<0.05).The incidence of heart damage was significantly increased and the days of fever was significantly prolonged in SMPP group(P<0.05).Phospholipid was a risk factor for mixed virus infection in MPP(OR=0.34,P<0.05).The AUC of phospholipid was 0.604(sensitivity 0.904,specificity 0.36),and the cut-off value was 1.685mmol/L,P<0.05.2.There were 27 boys and 23 girls in the case group with an average age of 6.0±3.65 years,and the control group consisted of 28 boys and 22 girls with an average age of 6.62±2.64 years.A total of 392 different metabolites were detected.Compared with the control group,306 metabolites were decreased and 86 increased in case group.Forty-one differential metabolites with variable important in projection(VIP)values>5 and P<0.05 were demonstrated,mainly concentrated on phospholipid.38 metabolites were significantly lower in the case group,4 metabolites were significantly higher than that of the control group.3.Metabolic enrichment analysis showed that different metabolites were related to the biosynthesis of phenylalanine,tyrosine,tryptophan,unsaturated fatty acid,ammonia acyl tRNA and insulin signaling pathway,as well as the metabolism of ABC transporters.4.For further analysis of the result before,MPP group was divided.There were 15 boys and 10 girls in SMPP group with an average age of 6.35±3.8 years,and mild MPP group consisted of 12 boys and 13 girls with an average age of 5.66±3.54 years.There was no significant difference in gender and age(P<0.05).14 phospholipids were selected for VIP>1,P<0.05,and FC>2 or FC<0.5.AUC of PC(18:4(6Z,9Z,12Z,15Z)/20:5(5Z,8Z,11Z,14Z,17Z)was 0.6864(sensitivity 0.96,specificity 0.44,and the AUC of PC(16:1(9Z)/16:1(9Z))was 0.664(sensitivity 0.64,specificity 0.72).Conclusion:1.Serum phospholipid level in children with SMPP was lower.We should paid attention to the tendency of SMPP when phospholipid was lower than 1.79mmol/L.SMPP children with lower phospholipid level had longer fever time and higher incidence of heart damage.When serum phospholipid was lower than 1.685mmol/L,we should be alert to the possibility of MPP mixed virus infection.2.The metabolic profile of MPP children is significantly different from that of normal children.The biosynthesis of unsaturated fatty acids,aminoyl tRNA,phenylalanine,tyrosine,tryptophan,insulin signaling pathway and metabolism of ABC transporter are involved in the development of Mycoplasma pneumoniae pneumonia.3.Phosphatidylcholine were significantly decreased after Mycoplasma pneumoniae infection.PC(18:4(6Z,9Z,12Z,15Z)/20:5(5Z,8Z,11Z,14Z,17Z)and PC(16:1(9Z)/16:1(9Z))may help us to predict SMPP. |
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