A Study On The Relationship Between Serum S100? Or/and GDNF Expression And POCD And Their Diagnostic Value In Patients Undergoing Cardiac Valve-replacement Under CPB

Objective: To detect serum S100? protein and glial cell line-derived neurotrophic(GDNF)concentrations of the patients with RHD undergoing valve-replacement under extracorporeal circulation(CPB),analyze relationships between serum S100? or/and GDNF and postoperative cognitive dysfunction(POCD),and evaluate their diagnostic significance and application value to POCD.Methods: 42 patients with RHD and undergoing valve replacement surgery were enrolled into this study.On 1st day before surgery and 7th day after surgery,all patients were tested,evaluated and scored by use of the Mini Mental State Scale(Mini-mental State Examination Scale,MMSE).According to the MMSE score on 7th day after surgery,the patients defined as POCD were divided into P group(POCD group)and the patients defined as non-POCD were divided into NP group(non-POCD group).Blood samples were adopted from all patients respectively at time point 1(T1,30 min before operation),T2(immediately after surgery),T3(1 day after surgery),T4(3 days after surgery)and T5(7 days after surgery)for detecting serum level of S100? protein and GDNF.Pearson correlation analysis was used to investigate respectively the correlation between POCD and S100? protein or GDNF expression.The receiver operating characteristic curve(ROC)was used to investigate diagnostic value of serum S100? protein and GDNF to POCD.Results: According to the MMSE score on 7th day after surgery,the incidence of POCD in all patients was 37.5%(15/43,Cases).The serum levels of GDNF and S100? protein at the T1 were not significantly different between two groups(P>0.05).However,compared with NP group,serum level of S100? protein was significantly higher and serum level of GDNF was significantly lower in P group at T2 to T5(P<0.05).There were a negative correlation between serum S100? protein and the 7th day MMSE score,a positive correlation between serum GDNF and the 7th day MMSE score,and a negative correlation between serum S100? protein and serum GDNF(P<0.05).As a single diagnostic biomarker for POCD,the serum level of S100? protein demonstrated an AUC of 0.853 with sensitivity of 77.6% and specificity of 75.4%.As a single diagnostic biomarker for POCD,the serum level of GDNF also demonstrated an AUC of 0.901 with sensitivity of 80.9% and specificity of 83.3%.As allied diagnostic biomarkers,serum levels of S100? protein and GDNF demonstrated an AUC of 0.953 with sensitivity of 87.5% and specificity of 88.6%.Conclusions: The serum level of S100? protein was significantly increased and serum level of GDNF was significantly decreased in patients with POCD.The serum level of S100? protein was negatively correlated with POCD and may be diagnostically valuable.The serum level of GDNF was positively correlated with POCD and may also be diagnostically valuable.The combined serum levels of S100? protein and GDNF,as allied diagnostic biomarkers of POCD,may be better than single application of serum S100? protein or GDNF in patients with RHD undergoing cardiac valve replacement under CPB.