Serum Levels Of Inflammatory Cytokines And Expression Of BCL-2 And BAX MRNA In Peripheral Blood Mononuclear Cells In Patients With Chronic Heart Failure

Heart failure(HF),as the complex clinical syndrome that results from any structure or functional impairment of ventricular filling or ejection of blood,is one of the most common worldwide and progressive disease.Since the incidence of the disease increases with the aging population,its mortality and admission rate of heart failure remain highest,which contributes to the associated costs and the load of society.It shortens life expectancy and seriously influences quality of life of its patients.According to the development speed of heart failure,it can be divided into acute heart failure(AHF)and chronic heart failure(CHF).Chronic heart failure is more commonly seen.Symptoms gradually show up over time,and condition is getting worse by the persistence of the cause.Nowadays,the treatment of chronic heart failure includes drug therapy and device therapy.Drug therapy includes angiotensin converting enzyme inhibitor(ACEI),angiotensin receptor inhibitor(ARB),β receptor blocker,and mineralocorticoid receptor antangonist(MRA).Based on recent statistics,angiotensin receptor/neprilysin inhibitor(ARNI)has been associated with improvement in hospital admission and mortality from heart failure.Guidelines now recommend substitution of ACEI or ARB with ARNI in appropriate patients.New drugs,targeting other mechanisms of action,for example cardiac myosin activators,are under investigation for patients with heart failure.Left ventricular assist devices are commonly used in patients with severe symptoms.At present,drug therapy for chronic heart failure is gradually changing from short-term hemodynamic/pharmacological measures for instance cardiotonic drugs,diuretics and vasodilators to repairing strategy with neuroendocrine inhibitors.However,there is no definite treatment plan for reversing the course of the failing heart.Therefore,how to effectively prevent and treat chronic heart failure is still an urgent clinical issiue.The mechanism of chronic heart failure is complex.Although there are various theories,they are still not quite clear.According to the cytokine hypothesis,CHF progresses since proinflammatory signals are mediated by a variety of cytokines,which induces cadiomyocyte hypertrophy,apoptosis and fibrosis and ultimately leads to adverse cardiac remodeling.Furthermore,certain cytokines are considered as biomarkers.Several studies have shown raised levels of inflammatory cytokines for example tumor necrosis factor(TNF)-α,interleukin(IL)-1β and IL-6,which are involved in inducing cardiomyocyte hypertrophy and apoptosis,and deteriorate the inflammation.However,the relationship between these inflammatory factors and cardiac function in patients with chronic heart failure is still controversial.Cardiomyocyte apoptosis is another major pathogenesis of chronic heart failure.Apoptosis plays an important role in various physiological processes including embryogenesis,normal tissue homeostasis and aging.Studies on both human and animal models suggest that apoptosis is associated with heart failure,and apoptosis is involved in the development from cardiac hypertrophy to the heart failing.Studies also confirmed that cardiomyocyte apoptosis plays an important role in the development of left ventricular dysfunction in heart failure with reduced ejection fraction.B-cell lymphoma-2(BCL-2)family proteins have pro-or anti-apoptosis activities.BCL-2 in this family is an anti-apoptotic member.As an pro-apoptosis member,BAX(BCL-2 associated X protein)is a negative regulator of apoptosis.There are few studies on BCL-2 and BAX in cardiomyocyte apoptosis ao far.There were no reports on the levels of BCL-2 and BAX in circulating inflammatory cells of CHF patients,and the relationship between BCL-2 and BAX levels and cardiac function was unknown.This study was designed to investigate the relationship between serum inflammatory cytokines for example IL-1β,IL-6,TNF-α and BCL-2,BAX in peripheral blood mononuclear cells and cardiac function and left ventricular ejection fraction(LVEF)in patients with chronic heart failure.Part One Serum levels of inflammatory cytokines in patients with CHF and their relationship with cardiac functionObjective: To explore the relationship between serum concentrations of IL-1β,IL-6,TNF-α and cardiac function and left ventricular ejection fraction by measuring serum concentrations of these inflammatory cytokines,and measuring left ventricular ejection fraction and evaluating cardiac function of the subjects.Methods: Sixty patients with chronic heart failure and 30 healthy controls were enrolled.The venous blood samples of the subjects were collected.Serum levels of IL-1β,IL-6 and TNF-α were determined by ELISA.Cardiac functions were evaluated by New York Heart Association(NYHA)functional classification system.Left ventricular ejection fraction was measured by transthoracic color Doppler echocardiography.Results:1.Baseline clinical characteristics of subjects: The causes of CHF group were ischemic heart disease(coronary heart disease,CHD),hypertensive heart disease(HHD)and cardiomyopathy(CM).Subjects in CHD group were older than those in HHD and CM group.The proportion of smoking in CHD group was higher than that in HHD and CM group(P<0.01).The proportion of hypertension in HHD group was higher than that in CHD group,and the proportion of hypertension in CHD group was higher that in CM group(P<0.01).The proportion of diabetes mellitus(DM)in CHD group was higher than that in HHD group,and the proportion of DM in HHD group was higher than that in CM group(P<0.01).The proportion of usage of asprin and statins in CHD group was higher than that of HHD group and CM group.The value of left ventricular ejection fraction(LVEF)in CHF group was lower than that in control group(P<0.01).The values of N-terminal pro-BNP,left ventricular end-diastolic dimension(LVEDD),left atrium diameter(LAD),right ventricular diameter(RVDD)in CHF group were lager than that in control group(P<0.01).2.Compared with the control group,The serum concentrations of inflammatory cytokines IL-1β,IL-6 and TNF-α in CHF group increased(P<0.01).Respectively compared with the control group,the serum levels of inflammatory cytokines IL-1β,IL-6 and TNF-α increased in the three etiological subgroups(P<0.05).There was no significant difference in serum levels of IL-1β,IL-6 and TNF-α between the three subgroups(P>0.05).3.Serum levels of inflammatory cytokines IL-1β,IL-6 and TNF-α were positively correlated with NYHA class in CHF group(P<0.05).4.Serum levels of inflammatory cytokines IL-1β,IL-6 and TNF-α were negatively correlated with LVEF in CHF group(P<0.01).5.Serum levels of inflammatory cytokines IL-1β、IL-6 and TNF-α were not correlated with each chamber diameter in CHF group(P>0.05).Conclusion: Elevated serum levels of IL-1β,IL-6 and TNF-α in CHF group suggest that there is an increase of inflammatory cytokines in circulation during the stable period of chronic heart failure caused by various causes.And inflammation is involved in the stage of stable stage of chronic heart failure.Serum levels of IL-1β、IL-6 and TNF-α were positively correlated with cardiac function and negatively correlated with LVEF,which indiacted that they are correlated with the severity,and could be one of the prognostic factors of CHF.Part Two Levels of BCL-2 and BAX mRNA in peripheral blood mono-nuclear cells(PBMCs)and their relationship with cardiac function in patients with CHFObjective: To explore the relationship between mRNA level of BCL-2,BAX mRNA and cardiac function,left ventricular ejection fraction by measuring relative content of BCL-2 and BAX mRNA in PBMCs,measuring left ventricular ejection fraction and evaluating cardiac function of the subjects.Methods: Sixty patients with chronic heart failure and 30 healthy controls were enrolled.The venous blood samples of the subjects were collected.Monocytes were isolated and cultured from peripheral blood and mRNA was extracted.Relative content of BCL-2 and BAX mRNA were measured by quantitative reverse transcription-polymerase chain reaction(qRT-PCR).Cardiac functions were evaluated by New York Heart Association(NYHA)functional classification system.Left ventricular ejection fraction was measured by transthoracic color Doppler echocardiography.Results:1.Baseline clinical characteristics of subjects: Same as part1.2.Compared with the control group,the level of BCL-2 mRNA in PBMCs in CHF group decreased(P<0.01),and the level of BAX mRNA increased(P<0.01).Respectively compared with the control group,the level of BCL-2 and BAX mRNA in PBMCs showed a difference in the three etiological subgroups(P<0.05).There was no significant difference in the level of BCL-2 and BAX mRNA between the three subgroups(P>0.05).3.The level of BCL-2 mRNA in PBMCs were negatively correlated with cardiac functional class in CHF group(P<0.05).And the level of BAX mRNA were positively correlated with NYHA class(P<0.05).4.The level of BCL-2 mRNA in PBMCs were positively correlated with LVEF in CHF group(P<0.01).And the level of BAX mRNA were negatively correlated with LVEF(P<0.01).5.The level of BAX mRNA in PBMCs were positively correlated with the levels of NT-proBNP in CHF group(P<0.01).The level of BCL-2 mRNA were not correlated with the levels of NT-proBNP(P>0.05).6.The level of BAX mRNA in PBMCs were positively correlated with LVEDD in CHF group(P<0.05).The level of BCL-2 mRNA were not correlated with LVEDD(P>0.05).Conclusion: BCL-2 and BAX,a pair of apoptosis-related genes,change significantly in the expression of chronic heart failure.And apoptosis is involved in the stage of stable stage of chronic heart failure.Various etiologies may lead to the common changes of these apoptosis-related genes.The level of mRNA of these genes is correlated with the severity of CHF and may be one of the prognostic factors of CHF.