The Role Of MTOR Pathway In Peritoneal Fibrosis And The Value Of PWV To Predict CVD In PD Patients

The aim of this study is to find the methods to prevent peritoneal fibrosis and cardiovascular disease(CVD)in peritoneal dialysis(PD)patients so as to further improve their prognosis.In the first part,the rats were intraperitoneally injected with 0.1%chlorhexidine glucose(CG)1ml/100g daily.All of them were sacrificed at 3 or 5 weeks later,respectively.The HE and Masson staining of rats' parietal peritonea showed the typical manifestation of peritoneal dialysis.The immunohistochemistry,western blotting(WB)and RT-PCR all showed the expressions of fibrosis-related proteins(FN,Col 1 and a-SMA)in the model groups were notably up-regulated.Through the WB,we revealed that the expression of p-mTOR,p-Akt and p-p70S6K in model group also significantly increased.These findings suggested that it was easily to establish a peritoneal fibrosis animal model induced by CG and the mTOR pathway was significantly activated during peritoneal fibrosis.In the second part,rapamycin(RAPA)and BEZ235 were used to treat the peritoneal fibrosis.Pathological examinations of rats'parietal peritonea displayed that the peritoneal fibrosis significantly alleviated after the treatment of mTOR blockers.The results of immunohistochemistry,WB and RT-PCR showed both RAPA and BEZ235 could obviously reduce extracellular matrix deposition and angiogenesis.Next,the expressions of mTOR pathway were observed by WB.The results revealed the expressions of p-Akt,p-mTOR and p-p70S6K in group BEZ235 decreased significantly.Unlike the results of group BEZ235,the expressions of p-mTOR and p-p70S6K were significantly down-regulated in group RAPA,while the expression of p-Akt didn't change.These results implied that both RAPA and BEZ235 had good effects of anti-peritoneal fibrosis and RAPA didn't cause the up-regulation of p-Akt by negative feedback.In the third part,we utilized quantitative proteomics to screen the differential proteins of rats' mesenteries in each groups and identified them by RT-PCR and immunohistochemistry.The results of proteomics demonstrated the S100A8 and S100A9 were markedly up-regulated,while the mitochondrial transcription termination factor-4(MTERF-4)and olfactory receptors were significantly down-regulated during peritoneal fibrosis.The RT-PCR and immunohistochemistry were applied to verify the S100A8 and S100A9.The results revealed the expressions of S100A8 and S100A9 were significantly higher in model group than those in control group,while the expressions of S100A8 and S100A9 markedly decreased after the treatment of mTOR blockers.Therefore,we supposed that the S100A8 and S100A9 might become the new biomarkers or therapeutic targets for peritoneal fibrosis.In the last part,59 PD patients in Ruijin Hospital from Jan 2012 to Dec 2012 were enrolled.All of them underwent ABPM,echocardiography,PWV and lab tests.According to the results of PWV,the patients were divided into group A(>9m/s)or group B(?9m/s).The results indicated that PWV was positively correlated with age,left atrial diameter,left ventricular mass index and 24H average systolic blood pressure.Age and 24H average SBP were risk factors of higher PWV.The cumulative survival rate and new CVD free survival in the group A were markedly lower than those in the group B.Elder and higher PWV were risk factors of CVD in PD patients.It is implied that PWV is a valuable predictor for CVD and death in PD patientsIn summary,our conclusions were as follows:1)It is simple and reproducible to establish peritoneal fibrosis models by CG.2)Both RAPA and BEZ235 have good effects of anti-peritoneal fibrosis.3)S100A8,S100A9 may be the potential biomarkers or therapeutic targets for peritoneal fibrosis.4)PWV is a valuable predictor for CVD and death in PD patients.