The Role And Regulating Mechanism Of Smooth Muscle Progenitor Cells During The Intimal Hyperplasia Of Outflow Limb Vein In Arteriovenous Fistula

Part?The role of the smooth muscle like cells during the native AVF dysfunction and the possible regulating mechanism by inflammatory factors in the outflow venous neointimal hyperplasiaObjective To study the role of the smooth muscle like cells?SMLCs?in the outflow venous neointimal hyperplasia of native AVF dysfunction and investigate the expression of inflammatory factors on venous intimal hyperplasia to discuss the possible regulating mechanism.Methods The specimens from the patients suffered from dysfunction of AVF were used to analyze the histological change of vascular lesions via immunohistochemical technique.The main inflammatory factors regulating the process of venous intimal hyperplasia were screened on their expression levels by PCR and Western blot technique.Results The wall of outflow vein thickened obviously because of the intimal hyperplasia?median intimal thickness>67.3?m?,and plenty of SMLCs were found in the venous intima of AVF.The expression levels of RANTES,MCP-1 and VEGF-A were much higher,especially the levels of RANTES and MCP-1.The main inflammatory factors were secreted by monocytes and macrophages in early stage of intimal hyperplasia lesion;however,in mid and advanced stage,they were possiblely secreted by SMLCs to maintain SMLCs continued proliferation themselves.Conclusions The majority of neointima cells were SMLCs,which could express the smooth muscle marker?-SMA and express RANTES and MCP-1 to sustain the venous continued neointimal hyperplasia.The cytokines and inflammatory factors may play a vital role in the process of neointimal hyperplasia of AVF.Part?MicroRNA-155 promote the venous intimal hyperplasia via regulating the expression of RANTES in the smooth muscle like cellsObjective To study the mechanism by wihch miR-155 regulating the proliferation of SMLCs in the outflow venous neointima of AVF.Methods The AVF animal models of carotid artery to external jugular vein were created with C57BL/6 mice and miR-155 gene knockout mice with C57BL/6 background respectively.The vein limb specimens of AVF were harvested in week 1,2,3,4 after operation.The histological change of venous intima lesions were analyzed through immunohistochemical technique.The change of cytokines and inflammatory factors and the proliferation of SMLCs were investigated in mRNA and protein levels by PCR and western blot.In vitro,the regulating mechanism of miR-155 on the expression of cytokines and the proliferation of SMLCs were studied.Results MiR-155 gene knockout could reduce the expression of RANTES,inhibit the proliferation of SMLCs,and relieve venous intimal hyperplasia and vascular stenotic remolding of AVF significantly.In venous intima of miR-155^-/-AVF,the expression of several cytokine reduced.MiR-155 could promote the expression of RANTES in SMLCs via ERK and NF-?B pathway,and could increase SMLCs proliferation and extracellular matrix expression.Conclusions MiR-155 could increase the SMLCs proliferation and extracellular matrix expression indirectly which could result in neointimal hyperplasia by regulating the expression of SMLCs-derived cytokines and inflammation factors via ERK and NF-?B pathway.Part?The smooth progenitor cells?SMPCs?of venous adventitia can migrate to intima and differentiate into SMLCsObjective To determine the source of the SMLCs in AVF outflow vein limb neointima,and investigate the mechanism that induce the migration,proliferation,and differentiation of the SMPCs in the venous intimal hyperplasia.Methods In order to determine the source of SMLCs,the AVF models were created in C57BL/6 mice and eGFP transgene mice who received each other's bone marrows transplantation respectively and the inflammatory and smooth muscle cells marker in the venous intima were investigated dynamically.The flow cytometry technique were used to sort out the non-bone marrow derived?non-BMD?eGFP⁺cells in the adventitia,then the cells were cultured and studied in vitro.The eGFP⁺cells were identified by the stem cell marker Sca-1 and their mechanism of migration,proliferation,and differentiation were analyzed.Results The non-BMD eGFP⁺cells could express stem cell marker Sca-1 and can differentiate into SMLCs,which could be regarded as SMPCs.They could express the smooth cell early stage marker SM-22?,but not SM-MHC.MiR-155 can promote the migration,proliferation and differentiation of SMPCS to by regulating the express of RANTES.Conclusions SMPCs can migrate into the intima and differentiate to SMLCs,which was regulated by miR155 through promoting cytokines and inflammatory factors expession.