Endothelial Progenitor Cells Expressing HTK1 Gene Improved The Cardiac Reserve And Structure In Rats With Doxorubicin-induced Heart Failure

BackgroundHeart failure(HF)is the end-stage of cardiovascular diseases,which causes high morbidity,high mortality and seriously lowers quality of life and survival rate.The pathological remodeling of HF involves cardiomyocyte hypertrophy,mitochondrial dysfunction,abnormal calcium homeostasis,collagen deposition,endothelial dysfunction,and inflammatory infiltration,et al.To date,even though drugs,such as angiotensin-converting enzyme inhibitors(ACEI)and ?-blockers can relieve symptoms,the therapeutic effect about pathological remodeling of HF is not enough.Stem cell-based therapy as a regenerative medicine has significant meanings for therapy of HF.Endothelial progenitor cells(EPCs)as one type of stem cells can promote angiogenesis and repair injured vascular in cardiovascular diseases.EPCs have unique characteristics,such as immunomodulatory capability and homing to sites of injury,which can be used as a type of biological drug to cure injured heart tissue.Human tissue kallikrein 1(hTK1)is one of many subtypes of tissue kallikrein family which belongs to kallikrein-kinin system and has many physiological functions,such as downregulating inflammation,thrombogenesis,apoptosis and fibrosis.EPCs expressing hTK1 gene(hTK1-EPCs)have not been established in doxorubicin-induced HF.This study aims to determine whether hTK1-EPCs improve cardiac structure and function and explore relative mechanism in doxorubicin-induced HF.ObjectivesThis study aims to determine that in doxorubicin-induced HF model whether EPCs expressing hTK1 gene home to heart tissue and improve cardiac structure and function.MethodsIn vitro,we isolated and identified EPCs.After successfully transducing adenovirus carrying green fluorescent protein(Ad/GFP)or hTK1(Ad/hTK1)into EPCs,the migration of EPCs were tested using Transwell assay and wound repair assay.In vivo,Wistar rats were randomly divided into four groups:the normal control group(NC),the doxorubicin group(Dox),the Ad/GFP-EPC group and the Ad/hTK1-EPC group.2 x105 Ad/GFP-EPCs or Ad/hTK1-EPCs were injected into animals via caudal vein.Twenty-four hours after that,the model of doxorubicin-induced HF was constructed through intermittent intraperitoneal injections doxorubicin.Cardiac function and structure were evaluated using transthoracic echocardiography.Histopathology was determined using hematoxylin-eosin staining.The location and expression of hTK1 protein was tested using immunofluorescent assay,immunohistochemistry and western blot.Apoptosis was analyzed using transferase-mediated dUTP nick-end labeling(TUNEL)assay.Masson's trichrome staining was evaluated intercellular and perivascular collagen deposition.1.We isolated and identified EPCs.Adenovirus carrying GFP gene or hTK1 gene were efficiently transduced into EPCs.2.In the Ad/hTK1-EPC group,numbers of EPCs were more and the wound area was reduced,which indicated that hTK1 promoted the migration of EPCs.3.In vivo,we successfully established doxorubicin-induced HF model of rats.Cardiac systolic function and structure were improved in the Ad/hTK1-EPC group,such as left ventricular ejection fraction(LVEF)and left ventricular fraction shortening(LVFS).4.hTK1-EPCs located in damaged heart and overexpressed hTK1 protein in the Ad/hTK1-EPC group.5.hTK1-EPCs alleviated myocardial hypertrophy,myocardial vacuolization and disorder of myocardial fiber tested using histopathologic staining.Intercellular collagen deposition and apoptosis were reduced in the Ad/hTK1-EPC group.Conclusion1.hTK1-EPCs could located in damaged heart.2.hTK1-EPCs improved cardiac function and structure by inhibiting apoptosis and fibrosis in doxorubicin-induced HF.