The heart is a source of circulating cardiotrophin-1 in humans

Investigation of maternal serum cardiotrophin-1 concentrations in pregnant women with preeclampsia; a prospective case-control study

OBJECTIVE

We aimed to investigate the cardiotrophin-1 (CT-1) concentrations in the serum of pregnant women with preeclampsia.

METHODS

This cross-sectional study was conducted with 88 pregnant women who applied to the Umraniye Training and Research Hospital Gynecology and Obstetrics Clinic between May 2022 and September 2022. The preeclampsia group consisted of 44 pregnant women diagnosed with preeclampsia, and the control group consisted of 44 healthy pregnant women matched with the preeclampsia group in terms of age and body mass index. Demographic characteristics, ultrasound and laboratory findings, perinatal outcomes, and maternal serum CT-1 concentrations were recorded.

RESULTS

Both groups were similar in terms of demographic features and the gestational week at blood sampling for CT-1. Preeclampsia and control groups were compared in terms of maternal serum CT-1 concentrations and no significant difference was found between the two groups (2061.4 pg/ml, 2168.5 pg/ml, respectively, p = .516). The preeclampsia group was divided into subgroups as mild and severe preeclampsia according to the severity of the disease and early-onset and late-onset preeclampsia according to the time of onset and compared with the control group in terms of maternal serum CT-1 concentration, no significant difference was found between the groups (p > .005, for all).

CONCLUSION

The serum CT-1 concentration of women whose pregnancy was complicated with preeclampsia was found to be similar to that of healthy controls. Although it has been shown in the literature that high serum CT-1 concentrations are associated with hypertensive heart diseases, its role in the pathophysiology of preeclampsia remains unclear.

Potential clinical biomarkers and perspectives in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a serious cardiovascular complication and the leading cause of death in diabetic patients. Patients typically do not experience any symptoms and have normal systolic and diastolic cardiac functions in the early stages of DCM. Because the majority of cardiac tissue has already been destroyed by the time DCM is detected, research must be conducted on biomarkers for early DCM, early diagnosis of DCM patients, and early symptomatic management to minimize mortality rates among DCM patients. Most of the existing implemented clinical markers are not very specific for DCM, especially in the early stages of DCM. Recent studies have shown that a number of new novel markers, such as galactin-3 (Gal-3), adiponectin (APN), and irisin, have significant changes in the clinical course of the various stages of DCM, suggesting that we may have a positive effect on the identification of DCM. As a summary of the current state of knowledge regarding DCM biomarkers, this review aims to inspire new ideas for identifying clinical markers and related pathophysiologic mechanisms that could be used in the early diagnosis and treatment of DCM.

A quantitative detection of Cardiotrophin-1 in chronic heart failure by chemiluminescence immunoassay

Background

Cardiotrophin‐1 (CT‐1) is a cytokine that could induce cardiomyocytes hypertrophy and dysfunction. Plasma CT‐1 might serve as a cardiac biomarker both in diagnosis, staging, and prognostic assessment of heart failure.

Methods

In this study, a one‐step paramagnetic particles‐based chemiluminescence immunoassay (MPs‐CILA) for rapid and sensitive detection of plasma CT‐1 was established. Plasma samples were directly incubated with biotin‐labeled anti‐CT‐1 antibody (bio‐Ab) and acridine ester labeled anti‐CT‐1 antibody (AE‐Ab) to form sandwiched complex. The sandwiched CT‐1 was then captured by streptavidin modified paramagnetic particles (MPs‐SA) for rapid separation and signal generation.

Results

The proposed MPs‐CLIA presents a laudable linear relationship ranging from 7.8 pg/mL to 200 ng/mL with a detection limit of 1.0 pg/mL. The recoveries of spiked human plasma samples at low (10pg/mL), medium (100 pg/mL), and high (800 pg/mL) levels of CT‐1 were 96%, 104%, and 110% respectively. The intra‐analysis coefficient variation (CVs) of the 3 samples was 8.92%, 6.69%, and 3.54%, respectively. And the inter‐analysis coefficient variation (CVs) was 9.25%, 10.9%, and 4.3%, respectively. These results strongly indicate high sensitivity, wide linear range, acceptable precision, and applicable reproducibility of the proposed method to detect plasma level of CT‐1. Finally, Plasma CT‐1 from 140 subjects with or without chronic heart failure was analyzed to assess the clinical application of MPs‐CILA.

Conclusions

Noteworthily, the MPs‐CLIA method is highly automated such that it is suitable for high‐throughput detection of CT‐1 in clinical inspection.

Circulating biomarkers in the early detection of hypertensive heart disease: usefulness in the developing world

Although the varying phenotypic spectra of hypertensive heart disease (HHD) can be assessed by electrocardiography (ECG), echocardiography and cardiovascular magnetic resonance (CMR), ECG criteria for left ventricular hypertrophy (LVH) are insensitive, while echocardiography and CMR are expensive, less readily available and often lack requisite expertise. Consequently, the use of circulating biomarkers in the diagnosis and prognostication of HHD beyond the traditional N-terminal pro- b-type natriuretic peptide (NT-proBNP) and B-type natriuretic peptide (BNP) have become an attractive alternative. We carried out a PubMed and Google Scholar databases' search of original articles on circulating biomarkers used in the diagnosis of the different spectrum of HHD over the last 10 years [2005-2015] in humans. Fourteen studies met the inclusion criteria with NT-pro BNP being the most studied circulating biomarker in HHD followed by soluble ST2 (sST2). There is a lack of data on the use of circulating biomarkers in HHD. There is a need to explore further this area of investigative cardiology.

Effect of cardiac resynchronization therapy on cardiotrophin-1 circulating levels in patients with heart failure

Cardiotrophin-1 (CT-1) is a member of the interleukin (IL-6) family of cytokines. Plasma CT-1 levels correlate with the left ventricle mass index in patients with dilatated cardiomyopathy and congestive heart failure (CHF). The aim of this paper was to evaluate CT-1 plasma levels, before and after cardiac resynchronization therapy CRT, and to characterizeits prognostic role in patients with CHF. Fifty-two consecutive patients (M/F = 39/13; 56 ± 11 years old) underwent clinical and echocardiographic evaluation, and blood sample collection at baseline. The same evaluation was repeated 6.4 ± 0.79 months after CRT. Patients with a decreased LV end-systolic volume by at least 15% (reverse remodeling) were considered echo responders to CRT. Twenty-nine patients (56%) were responders to CRT. After CRT, only 15 patients (29%) showed increased CT-1 after CRT. They were all non responders to CRT. A multivariate, logistic model showed CT-1 as an independent predictor of CRT echo response (p = 0.005; OR 0.97). During follow-up (18 ± 7 months), 21 cardiac events in 18 patients occurred. A Cox multivariable model showed plasma BNP pre-CRT (p = 0.02; CI 1.2-5.6; OR 3.1) and CT1 post-CRT (p = 0.01; CI 1.4-4.3; OR 2.7) as independent predictors of cardiac events. Analysis of CT-1 plasma levels deserves future consideration for larger, longitudinal studies in patients with CHF.

Myocardial cardiotrophin-1 is differentially induced in congenital cardiac defects depending on hypoxemia

ABSTRACT: Aim: Cardiotrophin-1 (CT-1) is upregulated by hypoxemia and hemodynamic overload and is characterized by potent hypertrophic and protective properties on cardiac cells. This study aimed to investigate whether CT-1 is differentially induced in the myocardium of infants with congenital cardiac defects depending on hypoxemia. Methods & results: Infants with Tetralogy of Fallot (n = 8) or with large nonrestrictive ventricular septal defect (n = 8) undergoing corrective surgery were investigated. Expression of CT-1 was assessed at mRNA and protein levels in the right atrial and ventricular myocardium. The activation of the STAT-3 and VEGF were measured. Degradation of cardiac troponin-I served as a marker of myocardial damage. CT-1 was detected in all patients with levels negatively correlating to the arterial oxygen saturation. Higher CT-1 expression in Tetralogy of Fallot patients was associated with activation of the JAK/STAT pathway and higher cardiac troponin-I degradation. Conclusion: CT-1 may mediate myocardial hypertrophy and dysfunction in infants with congenital cardiac defects, particularly in those with hypoxemia.

Association of cardiotrophin-1 with myocardial fibrosis in hypertensive patients with heart failure

Cardiotrophin-1 has been shown to be profibrogenic in experimental models. The aim of this study was to analyze whether cardiotrophin-1 is associated with left ventricular end-diastolic stress and myocardial fibrosis in hypertensive patients with heart failure. Endomyocardial biopsies from patients (n=31) and necropsies from 7 control subjects were studied. Myocardial cardiotrophin-1 protein and mRNA and the fraction of myocardial volume occupied by collagen were increased in patients compared with controls (P<0.001). Cardiotrophin-1 overexpression in patients was localized in cardiomyocytes. Cardiotrophin-1 protein was correlated with collagen type I and III mRNAs (r=0.653, P<0.001; r=0.541, P<0.01) and proteins (r=0.588, P<0.001; r=0.556, P<0.005) in all subjects and with left ventricular end-diastolic wall stress (r=0.450; P<0.05) in patients. Plasma cardiotrophin-1 and N-terminal pro-brain natriuretic peptide and serum biomarkers of myocardial fibrosis (carboxy-terminal propeptide of procollagen type I and amino-terminal propeptide of procollagen type III) were increased (P<0.001) in patients compared with controls. Plasma cardiotrophin-1 was correlated with N-terminal pro-brain natriuretic peptide (r=0.386; P<0.005), carboxy-terminal propeptide of procollagen type I (r=0.550; P<0.001), and amino-terminal propeptide of procollagen type III (r=0.267; P<0.05) in all subjects. In vitro, cardiotrophin-1 stimulated the differentiation of human cardiac fibroblast to myofibroblasts (P<0.05) and the expression of procollagen type I (P<0.05) and III (P<0.01) mRNAs. These findings show that an excess of cardiotrophin-1 is associated with increased collagen in the myocardium of hypertensive patients with heart failure. It is proposed that exaggerated cardiomyocyte production of cardiotrophin-1 in response to increased left ventricular end-diastolic stress may contribute to fibrosis through stimulation of fibroblasts in heart failure of hypertensive origin.

Stimulatory Effects of Cardiotrophin 1 on Atherosclerosis

Cardiotrophin 1 (CT-1), an interleukin-6 family cytokine, was recently shown to be expressed in the intima of early atherosclerotic lesions in the human carotid artery. CT-1 stimulates proatherogenic molecule expression in human vascular endothelial cells and monocyte migration. However, it has not been reported whether CT-1 accelerates atherosclerosis. This study was performed to examine the stimulatory effects of CT-1 on human macrophage foam cell formation and vascular smooth muscle cell migration and proliferation in vitro, and on the development of atherosclerotic lesions in apolipoprotein E–deficient (ApoE −/− ) mice in vivo. CT-1 was expressed at high levels in endothelial cells and macrophages in both humans and ApoE −/− mice. CT-1 significantly enhanced oxidized low-density lipoprotein–induced foam cell formation associated with increased levels of CD36 and acyl-CoA:cholesterol acyltransferase-1 expression in human monocyte–derived macrophages. CT-1 significantly stimulated the migration, proliferation, and collagen-1 expression in human aortic vascular smooth muscle cells. Four-week infusion of CT-1 into ApoE −/− mice significantly accelerated the development of aortic atherosclerotic lesions with increased monocyte/macrophage infiltration, vascular smooth muscle cell proliferation, and collagen-1 content in the aortic wall. Activation of inflammasome, such as apoptosis-associated speck-like protein containing a caspase recruitment domain, nuclear factor κB, and cyclooxygenase-2, was observed in exudate peritoneal macrophages from ApoE −/− mice infused with CT-1. Infusion of anti–CT-1–neutralizing antibody alone into ApoE −/− mice significantly suppressed monocyte/macrophage infiltration in atherosclerotic lesions. These results indicate that CT-1 accelerates the development of atherosclerotic lesions by stimulating the inflammasome, foam cell formation associated with CD36 and acyl-CoA:cholesterol acyltransferase-1 upregulation in macrophages, and migration, proliferation, and collagen-1 production in vascular smooth muscle cells.

Association of cardiotrophin-1 with left ventricular systolic properties in asymptomatic hypertensive patients

OBJECTIVES

Cardiotrophin-1 (CT-1) induces hypertrophic growth and contractile dysfunction in cardiomyocytes. This cross-sectional study was aimed to analyze CT-1 associations with echocardiographically assessed left ventricular systolic properties taking into account the influence of left ventricular growth [i.e. left ventricular hypertrophy (LVH) and inappropriate left ventricular mass (iLVM)] in asymptomatic hypertensive patients.

METHODS

Serum CT-1 was measured by ELISA in 278 asymptomatic hypertensive patients with a left ventricular ejection fraction more than 50% and in 25 age and sex-matched normotensive patients.

RESULTS

Serum CT-1 was increased in hypertensive patients as compared to normotensive patients. CT-1 was directly correlated with parameters of left ventricular mass (LVM) and inversely correlated with parameters assessing myocardial systolic function and left ventricular chamber contractility in hypertensive patients, these associations being independent of a number of potential confounding factors. Interestingly, the associations of CT-1 with myocardial systolic function were independent of LVM even in patients with LVH or iLVM. In addition, there was a significant increment of serum CT-1 in hypertensive patients with LVH or iLVM, especially in those in whom LVH or iLVM were accompanied by impaired myocardial systolic function, as compared to the remaining hypertensive patients and normotensive patients. Plasma amino-terminal pro-brain natriuretic peptide was not correlated with any of the assessed left ventricular systolic parameters in either group of patients.

CONCLUSION

These findings suggest that serum CT-1 is associated with myocardial systolic dysfunction in asymptomatic hypertensive patients, independently of LVM, even in those patients with pathologic left ventricular growth.

Update on the pathophysiological activities of the cardiac molecule cardiotrophin-1 in obesity

Cardiotrophin-1 (CT-1) is a heart-targeting cytokine that has been reported to exert a variety of activities also in other organs such as the liver, adipose tissue, and atherosclerotic arteries. CT-1 has been shown to induce these effects via binding to a transmembrane receptor, comprising the leukaemia inhibitory factor receptor (LIFRβ) subunit and the glycoprotein 130 (gp130, a common signal transducer). Both local and systemic concentrations of CT-1 have been shown to potentially play a critical role in obesity. For instance, CT-1 plasma concentrations have been shown to be increased in metabolic syndrome (a cluster disease including obesity) probably due to adipose tissue overexpression. Interestingly, treatment with exogenous CT-1 has been shown to improve lipid and glucose metabolism in animal models of obesity. These benefits might suggest a potential therapeutic role for CT-1. However, beyond its beneficial properties, CT-1 has been also shown to induce some adverse effects, such as cardiac hypertrophy and adipose tissue inflammation. Although scientific evidence is still needed, CT-1 might be considered as a potential example of damage/danger-associated molecular pattern (DAMP) in obesity-related cardiovascular diseases. In this narrative review, we aimed at discussing and updating evidence from basic research on the pathophysiological and potential therapeutic roles of CT-1 in obesity.

Cardiac stem cells: A promising treatment option for heart failure

Cardiovascular diseases are the most common cause of death in the world. The development of heart failure is mainly due to the loss of cardiomyocytes following myocardial infarction and the absence of endogenous myocardial repair. Numerous studies have focused on cardiac stem cells (CSCs) due to their therapeutic benefit, particularly in the treatment of heart failure. It has previously been demonstrated that CSCs are able to promote the regeneration of cardiomyocytes in animals following myocardial infarction. However, the underlying mechanism(s) remain unclear. This review mainly discusses the cardioprotective effect of CSCs and the effect of CSCs on the function of cardiomyocytes, and compares the efficacies of CSCs from rats, mice and humans, thereby contributing to an improved understanding of CSCs as a promising treatment option for heart failure.

Cardiotrophin-1 in hypertensive heart disease

Hypertensive heart disease, here defined by the presence of pathologic left ventricular hypertrophy in the absence of a cause other than arterial hypertension, is characterized by complex changes in myocardial structure including enhanced cardiomyocyte growth and non-cardiomyocyte alterations that induce the remodeling of the myocardium, and ultimately, deteriorate left ventricular function and facilitate the development of heart failure. It is now accepted that a number of pathological processes mediated by mechanical, neurohormonal, and cytokine routes acting on the cardiomyocyte and the non-cardiomyocyte compartments are responsible for myocardial remodeling in the context of arterial hypertension. For instance, cardiotrophin-1 is a cytokine member of the interleukin-6 superfamily, produced by cardiomyocytes and non-cardiomyocytes in situations of biomechanical stress that once secreted interacts with its receptor, the heterodimer formed by gp130 and gp90 (also known as leukemia inhibitory factor receptor beta), activating different signaling pathways leading to cardiomyocyte hypertrophy, as well as myocardial fibrosis. Beyond its potential mechanistic contribution to the development of hypertensive heart disease, cardiotrophin-1 offers the opportunity for a new translational approach to this condition. In fact, recent evidence suggests that cardiotrophin-1 may serve as both a biomarker of left ventricular hypertrophy and dysfunction in hypertensive patients, and a potential target for therapies aimed to prevent and treat hypertensive heart disease beyond blood pressure control.

Cardiotrophin-1 in cardiovascular regulation

Cardiotrophin (CT)-1 was discovered by coupling expression cloning with an embryonic stem cell-based model of cardiogenesis. Comparison of similarity in amino acid sequence and conformational structure indicates that CT-1 is a member of the interleukin (IL)-6 type cytokine family that shares the transmembrane signaling protein, glycoprotein (gp) 130 as a receptor. These cytokines mediate overlapping pleiotropic actions on a variety of cell types including cardiac myocytes, hepatocytes, megakaryocytes, osteoclasts, and neuronal cells. CT-lmediates its hypertrophic and cytoprotective properties through the Janus kinase/signal transducers and activators of transcription (JAK/STAT), mitogen-activated protein (MAP) kinase, phosphatidylinositol (PI) 3 kinase, and nuclear factor kappa B (NFkappaB) pathways. CT-1 gene and protein are distributed not only in the heart, but also in the pulmonary, renal, gastrointestinal, cerebral, and muscular tissues. CT-1 could also be synthesized and secreted from vascular endothelial cells and adipocytes. CT-1 has hypertrophic actions on the cardiac myocytes, skeletal muscle cells, and smooth muscle cells as well as cytoprotective actions on the cardiac myocytes, neuronal cells, and hepatocytes. CT-1 is circulating in the body, and its plasma concentration is increased in various cardiovascular and renal diseases such as hypertension, congestive heart failure, myocardial infarction, valvular heart disease, metabolic syndrome, and chronic kidney disease. Treatment with CT-1 is beneficial in experimental animal models of cardiovascular diseases. CT-1 specifically protects the cardiac myocytes from ischemic damage when CT-1 is given not only prior to the ischemia, but also given at the time of reoxygenation. Current evidence suggests that CT-1 plays an important role in the regulation of the cardiovascular system.

Cardiotrophin-1 plasma levels are associated with the severity of hypertrophy in hypertrophic cardiomyopathy

AIMS

Cardiotrophin-1 (CT-1) is a cytokine that induces hypertrophy in cardiomyocytes and is associated with left ventricular hypertrophy (LVH) in hypertensive patients. The objective of this study was to evaluate whether plasma CT-1 is associated with hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

The study was performed in 124 patients with HCM. All patients underwent a full clinical evaluation and an echocardiogram. Left ventricular hypertrophy was evaluated by the measurement of the maximal LV wall thickness and the Spirito's LVH score. Plasma CT-1 was measured by an enzyme-linked immunosorbent assay. Compared with controls, patients with HCM exhibited higher (P < 0.001) plasma CT-1 levels. Significant correlations were found between CT-1 and maximal LV wall thickness (r = 0.284, P = 0.001) and the Spirito's LVH score (r = 0.287, P = 0.006) in HCM patients. In addition, the levels of CT-1 were higher (P = 0.02) in patients with severe LVH (maximal LV wall thickness ≥30 mm) than in patients with mild or moderate LVH (maximal LV wall thickness <30 mm).

CONCLUSIONS

These findings show that plasma CT-1 is associated with the severity of LVH in patients with HCM. Further studies are required to ascertain whether CT-1 is a diagnostic biomarker of this cardiomyopathy.

Cardiotrophin-1 induces tumor necrosis factor alpha synthesis in human peripheral blood mononuclear cells

Chronic heart failure (CHF) is associated with elevated concentrations of tumor necrosis factor (TNF) α and cardiotrophin-1 (CT-1) and altered peripheral blood mononuclear cell (PBMC) function. Therefore, we tested whether CT-1 induces TNFα in PBMC of healthy volunteers. CT-1 induced in PBMC TNFα protein in the supernatant and TNFα mRNA in a concentration- and time-dependent manner determined by ELISA and real-time PCR, respectively. Maximal TNFα protein was achieved with 100 ng/mL CT-1 after 3–6 hours and maximal TNFα mRNA induction after 1 hour. ELISA data were confirmed using immunofluorescent flow cytometry. Inhibitor studies with actinomycin D and brefeldin A showed that both protein synthesis and intracellular transport are essential for CT-1 induced TNFα expression. CT-1 caused a dose dependent nuclear factor (NF) κB translocation. Parthenolide inhibited both NFκB translocation and TNFα protein expression indicating that NFκB seems to be necessary. We revealed a new mechanism for elevated serum TNFα concentrations and PBMC activation in CHF besides the hypothesis of PBMC activation by bacterial translocation from the gut.

Cardiotrophin-1. Review

BACKGROUND

Cardiotrophin-1 is newly discovered chemokin with a lot of functions. Aim of our work was to describe most important of them.

METHODS

systematically scan of available scientific resources.

RESULTS

Cardiotrophin-1 stimulates the proliferation of cardiomyocytes. Cardiotrophin-1 expression and plasma values are elevated in individuals with heart failure and have high diagnostic efficacy for the heart failure. Plasma values are also an independent prognostic factor. Preliminary findings suggest that the determination of plasma cardiotrophin-1 may be useful for the follow-up of hypertensive heart disease in routine clinical practice. Cardiotrophin-1 also plays an important cardioprotective effect on myocardial damage, is a potent regulator of signaling in adipocytes in vitro and in vivo and potentiates the elevation the acute-phase proteins. Cardiotrophin-1 may play also an important protective role in other organ systems (such as hematopoietic, neuronal, developmental).

CONCLUSION

Cardiotrophin is a newly discovered chemokin with a lot of system effects and is stable in system circulation hence permitting its development in the routine clinical investigation.

CNTF-evoked activation of JAK and ERK mediates the functional expression of T-type Ca2+ channels in chicken nodose neurons

Culture of chicken nodose neurons with CNTF but not BDNF causes a significant increase in T-type Ca(2+) channel expression. CNTF-induced channel expression requires 12 h stimulation to reach maximal expression and is not affected by inhibition of protein synthesis, suggesting the involvement of a post-translational mechanism. In this study, we have investigated the biochemical mechanism responsible for the CNTF-dependent stimulation of T-type channel expression in nodose neurons. Stimulation of nodose neurons with CNTF evoked a considerable increase in signal transducer and activator of transcription (STAT3) and extracellular signal-regulated kinase (ERK) phosphorylation. CNTF-evoked ERK phosphorylation was transient whereas BDNF-evoked activation of ERK was sustained. Pre-treatment of nodose neurons with the Janus tyrosine kinase (JAK) inhibitor P6 blocked STAT3 and ERK phosphorylation, whereas the ERK inhibitor U0126 prevented ERK activation but not STAT3 phosphorylation. Both P6 and U0126 inhibited the stimulatory effect of CNTF on T-type channel expression. Inhibition of STAT3 activation by the selective blocker stattic has no effect on ERK phosphorylation and T-type channel expression. These results indicate that CNTF-evoked stimulation of T-type Ca(2+) channel expression in chicken nodose neurons requires JAK-dependent ERK signaling. A cardiac tissue extract derived from E20 chicken heart was also effective in promoting T-type Ca(2+) channel expression and STAT3 and ERK phosphorylation. The ability of the heart extract to stimulate JAK/STAT and ERK activation was developmentally regulated. These findings provide further support to the idea that CNTF or a CNTF-like factor mediates normal expression of T-type channels.

Association of depressed cardiac gp130-mediated antiapoptotic pathways with stimulated cardiomyocyte apoptosis in hypertensive patients with heart failure

OBJECTIVE

To investigate whether the glycoprotein (gp130)-mediated survival pathway, which protects cardiomyocytes from apoptosis, is depressed in left ventricular hypertrophy hypertensive patients with chronic heart failure.

METHODS

Transvenous endomyocardial biopsies were obtained in 52 hypertensive patients with left ventricular hypertrophy: 28 without heart failure and 24 with heart failure. gp130 and gp130-dependent antiapoptotic pathways p42/44 mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3 kinase (PI3K)/protein kinase B (Akt) as well as gp130 agonist cardiotrophin-1 were analyzed by reverse transcriptase-polymerase chain reaction and western blot. Apoptosis was assessed by DNA end-labeling (TUNEL), caspase-3 immunostaining and caspase substrate poly(ADP-ribose) polymerase cleavage.

RESULTS

gp130 protein expression (P < 0.05) and p42/44 MAPK and PI3K/Akt activation (P < 0.01) were decreased in heart-failure hypertensive patients compared with nonheart-failure hypertensive individuals. No changes in gp130 mRNA expression were found between the two groups. Cardiotrophin-1 was increased (P < 0.05) at both the mRNA and protein levels in heart-failure hypertensive individuals compared with nonheart-failure hypertensive individuals. Cardiomyocyte apoptosis was increased (P < 0.01) in heart-failure hypertensive individuals compared with nonheart-failure hypertensive individuals. Inverse correlations (P < 0.01) occurred between cardiomyocyte apoptosis and p42/44 MAPK and PI3K/Akt activation in all hypertensive patients. Cardiotrophin-1 correlated inversely (r = -0.554, P < 0.05) with gp130 in all hypertensive individuals. In cultured HL-1 cardiomyocytes, cardiotrophin-1 decreased (P < 0.05) the gp130:phosphorylated gp130 (at Ser782) ratio and increased (P < 0.05) gp130ubiquitination.

CONCLUSIONS

An association exists between depression of the gp130 cytoprotective pathway and stimulation of cardiomyocyte apoptosis in hypertensive patients that develop heart failure. Whether the excess of cardiotrophin-1 induces ligand-induced receptor down-regulation in these patients requires further study.

Plasma level of cardiotrophin-1 as a prognostic predictor in patients with chronic heart failure

BACKGROUND

Cardiotrophin-1 (CT-1) is a member of the interleukin (IL-6) family of cytokines and is increased in patients with chronic heart failure (CHF).

AIMS

To evaluate the prognostic role of CT-1 in patients with CHF.

METHODS AND RESULTS

We measured the plasma levels of CT-1, brain natriuretic peptide (BNP), and IL-6 in 125 patients with CHF. Patients were monitored for a mean follow-up period of 2.9 years. Plasma levels of CT-1 increased with severity of CHF. There was a significant negative correlation between plasma CT-1 and left ventricular ejection fraction. There was a significant correlation between plasma CT-1 and log IL-6. During the follow-up period, 37 patients died. High plasma levels of CT-1, BNP, and IL-6 were independent predictors of mortality on stepwise multivariate analysis. The hazard ratio for mortality in patients with plasma BNP>170 pg/mL and CT-1>658 fmol/mL was 2.48 (95% confidence interval, 1.217-5.060) compared to those with plasma BNP>170 pg/mL and CT-1<658 fmol/mL (p=0.0124).

CONCLUSION

These findings indicate that plasma CT-1 measurement provides additional prognostic information and that combined levels of CT-1 and BNP are more accurate at predicting mortality in patients with CHF than either marker alone.

Association of increased plasma cardiotrophin-1 with inappropriate left ventricular mass in essential hypertension

Inappropriate left ventricular mass is present when the value of left ventricular mass exceeds individual needs to compensate hemodynamic load imposed by increased blood pressure. The goal of this study was to investigate whether plasma concentration of cardiotrophin-1, a cytokine that induces exaggerated hypertrophy in cardiomyocytes with hypertensive phenotype, is related to inappropriate left ventricular mass in patients with essential hypertension. The study was performed in 118 patients with never-treated hypertension and without prevalent cardiac disease. The left ventricular mass prediction from stroke work (systolic blood pressurexDoppler stroke volume), sex, and height (in meters(2.7)) was derived. An observed left ventricular mass/predicted left ventricular mass value >128% defined inappropriate left ventricular mass. Plasma cardiotrophin-1 was measured by an enzyme-linked immunosorbent assay. The studies were repeated in a group of 45 patients after 1 year of antihypertensive treatment. At baseline 67 and 51 patients presented with appropriate and inappropriate left ventricular mass, respectively. Plasma cardiotrophin-1 was higher (P<0.001) in patients with inappropriate mass than in patients with appropriate mass and normotensive controls. A direct correlation was found between cardiotrophin-1 and observed left ventricular mass/predicted left ventricular mass ratio (r=0.330, P<0.001) in all hypertensive patients. After treatment, plasma cardiotrophin-1 decreased and increased in patients in which inappropriate left ventricular mass regressed and persisted, respectively, despite a similar reduction of blood pressure in the 2 subgroups of patients. Albeit descriptive in nature, these results suggest the hypothesis that an excess of cardiotrophin-1 may contribute to inappropriate left ventricular growth in hypertensive patients.

Cardiotrophin-1 induces interleukin-6 synthesis in human monocytes

BACKGROUND

Patients with congestive heart failure (CHF) show increased serum concentrations of cytokines like interleukin-6 (IL-6) and cardiotrophin-1 (CT-1). Additionally, monocyte function is modulated in CHF. The aim of this study was to examine if CT-1 is able to induce IL-6 in human monocytes and to investigate the underlying pathway.

METHODS

Separated peripheral blood monocytes of healthy volunteers were cultured with increasing concentrations of CT-1 for different periods. IL-6 mRNA was determined by RT-PCR or real-time PCR and IL-6 protein concentration in the supernatant by ELISA. Phosphorylation of signal transducer and activation of transcription (STAT) 3 was analyzed by western blot or by FACS analysis. To clarify the signalling pathway of CT-1 induced IL-6 expression various inhibitors of possible signal transducing molecules were used.

RESULTS

CT-1 induced IL-6 mRNA in monocytes in a time- and concentration-dependent manner. Maximal mRNA induction was detectable after 6h with 100 ng/ml CT-1. IL-6 protein also increased in a time- and concentration-dependent manner with a maximum after 48 h with 100 ng/ml CT-1. AG490 as well as SB 203580 and parthenolide blocked CT-1 induced IL-6 expression completely. AG 490 was able to inhibit STAT3 phosphorylation in western blot analysis completely. This indicates that JAK2/STAT3, p38 and nuclear factor kappaB (NFkappaB) are involved in this pathway. To exclude a possible influence of plastic adherence of monocytes on CT-1 induced IL-6 expression, we determined intracellular STAT3 phosphorylation in whole blood samples by FACS analysis and observed independently of culture conditions a CT-1 concentration-dependent STAT3 phosphorylation.

CONCLUSION

CT-1 induces IL-6 mRNA and protein expression in a time- and concentration-dependent manner. The underlying pathway is Janus kinase (JAK)2/STAT3, p38 and NFkappaB dependent. These data may explain increased IL-6 serum concentrations and altered monocyte function found in patients with CHF. Modulation of the CT-1 pathway might be a interesting strategy in the treatment of CHF.

Survival pathways in hypertrophy and heart failure: the gp130-STAT3 axis

Circulating levels of interleukin (IL)-6 and related cytokines are elevated in patients with congestive heart failure and after myocardial infarction. Serum IL-6 concentrations are related to decreasing functional status of these patients and provide important prognostic information.Moreover, in the failing human heart, multiple components of the IL-6- glycoprotein (gp)130 receptor system are impaired, implicating an important role of this system in cardiac pathophysiology.Experimental studies have shown that the common receptor subunit of IL-6 cytokines is phosphorylated in response to pressure overload and myocardial infarction and that it subsequently activates at least three different downstream signaling pathways, the signal transducers and activators of transcription 1 and 3 (STAT1/3), the Src-homology tyrosine phosphatase 2 (SHP2)-Ras-ERK, and the PI3K-Akt system. Gp130 receptor mediated signaling promotes cardiomyocyte survival, induces hypertrophy, modulates cardiac extracellular matrix and cardiac function. In this regard, the gp130 receptor system and its main downstream mediator STAT3 play a key role in cardioprotection. This review summarizes the current knowledge of IL-6 cytokines, gp130 receptor and STAT3 signaling in the heart exposed to physiological (aging, pregnancy) and pathophysiological stress (ischemia, pressure overload, inflammation and cardiotoxic agents) with a special focus on the potential role of individual IL-6 cytokines.

Cardiotrophin-1 induces interleukin-6 synthesis in human umbilical vein endothelial cells

In patients with chronic heart failure (CHF) increased plasma concentrations of proinflammatory cytokines are found. For example, the plasma interleukin-6 (IL-6) concentration correlates with disease severity. Beside IL-6 cardiotrophin-1 (CT-1), a member of the IL-6 superfamily, is also increased in CHF. We examined whether CT-1 is able to induce IL-6 in human umbilical vein endothelial cells (HUVEC) and characterised the underlying pathway. IL-6 mRNA was determined by real-time PCR and by RT-PCR in HUVEC which were stimulated with different CT-1 concentrations and for different time periods. IL-6 concentration in the supernatant was determined by ELISA. For the pathway determination following inhibitors were used: piceatannol (signal transducer and activation of transcription (STAT)3 phosphorylation), wortmannin (phosphatiylinositol 3-kinase (PI3K)), SB203580 (p38 mitogen-activated protein kinase (MAPK)), AG490 (Janus kinase (JAK)2), PD98059 (mitogen-activated protein kinase kinase (MEK) 1/2), parthenolide (nuclear factor kappaB) and cycloheximide (protein biosynthesis). CT-1 caused a concentration- and time-dependent increase in IL-6 mRNA in HUVEC with a maximal induction seen after 6 h (2-fold compared to control) with 100 ng/ml CT-1. In the supernatant of HUVEC a concentration- and time-dependent increase of IL-6 protein was found. A maximum effect with 100 ng/ml CT-1 was found after 24 h (11-fold compared to control). AG490, SB203580, piceatannol, parthenolide and cycloheximide inhibit CT-1 induced IL-6 mRNA and protein expression whereas wortmannin and PD98059 did not inhibit IL-6 expression. CT-1 induced both IL-6 mRNA and protein in a concentration- and time-dependent manner in HUVEC. The underlying pathway includes activation of JAK2, STAT3, p38 and NFkappaB. CT-1 induced IL-6 expression and requires protein synthesis and IL-6 is not stored intracellularly. We speculate that in CHF CT-1 might be in part responsible for increased IL-6 plasma concentrations. Modulation of the CT-1 pathway may be a further strategy in CHF treatment.

Jak/STAT/SOCS signaling circuits and associated cytokine-mediated inflammation and hypertrophy in the heart

Cytokines are important mediators of cardiac disease. Accumulating evidence indicates that members of the interleukin-6 family of cytokines promote cardiac hypertrophy through the activation of the Janus kinase-signal transducer and activator of transcription (Jak/STAT) pathway. Aberrant Jak/STAT signaling may promote progression from hypertrophy to heart failure. Suppressor of cytokine signaling (SOCS) proteins are underexplored, negative regulators of Jak/STAT signaling. SOCS proteins may also interact with other inflammatory pathways known to affect cardiac function. A better understanding of the therapeutic potential of these proteins may lead to the controlled progression of heart failure and the limitation of myocardial depression. This review summarizes the cardiophysiological effect of the IL-6 cytokine family, outlines the mechanistic pathway of Jak/STAT signaling, explores the regulatory role of SOCS proteins in the heart, and discusses the potential of using SOCS proteins clinically.

Screening for ventricular remodeling

Current guidelines emphasize the importance of preventing heart failure (HF) by targeting people with preclinical forms of the disease. Accordingly, there is considerable interest in identifying left ventricular (LV) remodeling, the fundamental substrate for HF, in asymptomatic individuals in the community. Increased LV mass and asymptomatic LV systolic and LV diastolic dysfunction are the remodeling phenotypes that could be potentially considered for population-wide screening. Plasma levels of natriuretic peptides (NP) have been extensively investigated for such screening purposes. However, a majority of investigations suggest that their performance characteristics are suboptimal for identifying LV remodeling phenotypes unless high-risk individuals (eg, older men with hypertension) are targeted. In general, the prevalence of LV systolic dysfunction in women is too low to justify screening. In recent reports, sequential screening strategies combining urine and plasma NP or plasma NP and hand-held portable echocardiography have been advocated as potential approaches to identify asymptomatic LV systolic dysfunction in a cost-effective manner. Additional studies are warranted to confirm these findings.

Usefulness of plasma cardiotrophin-1 in assessment of left ventricular hypertrophy regression in hypertensive patients

OBJECTIVE

We investigated whether regression of left ventricular hypertrophy (LVH) in response to antihypertensive treatment is associated with plasma cardiotrophin-1 (CT-1) in hypertensive patients.

METHODS

The study was performed in 47 patients with mild to moderate essential hypertension, and LVH was assessed echocardiographically. The family doctor gave antihypertensive treatment and followed all patients. LVH regression was diagnosed if the baseline left ventricular mass index (LVMI) decreased to normal values after 1 year of treatment. Plasma CT-1 was determined by an enzyme-linked immunosorbent assay.

RESULTS

The LVMI was normalized in 23 patients (49%) and persisted at an abnormally increased level in 24 patients (51%) after 1 year of treatment, whereas the reduction in clinic and home blood pressure was similar in the two groups: CT-1 decreased (-48%, P < 0.005) and increased (+35%, P < 0.05) in patients in whom LVH regressed and LVH persisted, respectively. Final values of CT-1 were inversely correlated (r = 0.534, P < 0.001) with the decrease in LVMI after treatment in all patients. A significant association (chi2 = 16.87, P < 0.001) was found between normalization of CT-1 and regression of LVH with treatment. A cut-off value of 41 fmol/ml for CT-1 provided a relative risk of 43.13 (95% confidence interval, 4.88-380.48) for detecting LVH regression.

CONCLUSION

These results show an association between treatment-induced decrease of plasma CT-1 and LVH regression in essential hypertension. Although preliminary, these findings suggest that the determination of plasma CT-1 may be useful for the follow-up of hypertensive heart disease in routine clinical practice.

Chronic cardiotrophin-1 stimulation impairs contractile function in reconstituted heart tissue

Cardiotrophin-1 (CT-1) is known to promote survival but also to induce an elongated morphology of isolated cardiac myocytes, leading to the hypothesis that CT-1, which is chronically augmented in human heart failure, might induce eccentric cardiac hypertrophy and contractile failure. To address this, we used heart tissues reconstituted from neonatal rat cardiac myocytes (engineered heart tissue, EHT) as multicellular in vitro test systems. CT-1 dose-dependently affected contractile function in EHTs. After treatment with 0.1 nM CT-1 (corresponds to plasma levels in humans) for 10 days, twitch tension significantly decreased to 0.30 +/- 0.04 mN (n = 15) vs. 0.45 +/- 0.04 mN (n = 16) in controls. Furthermore, positive inotropic effects of cumulative concentrations of Ca2+ and isoprenaline were significantly diminished. Maximum isoprenaline-induced increase in twitch tension amounted to 0.27 +/- 0.04 mN (n = 15) vs. 0.47 +/- 0.06 mN (n = 16) in controls (P < 0.001). When EHTs were treated for only 5 days, qualitatively similar results were obtained but changes were less pronounced. Immunostaining of whole mount EHT preparations revealed that after CT-1 treatment, the number of nonmyocytes significantly increased by 98% (1 nM, 10 days), and myocytes did not form compact, longitudinally oriented muscle bundles. Interestingly, expression of the Ca2+-handling protein calsequestrin was markedly reduced (69 +/- 7% of control) by treatment with CT-1 (0.1 nM, 10 days). In summary, long-term exposure to CT-1 induces contractile dysfunction in EHTs. Structural changes due to impaired differentiation and/or remodeling of heart tissue may play an important role.

Is plasma cardiotrophin-1 a marker of hypertensive heart disease?

OBJECTIVE

This study was designed to investigate whether plasma concentration of cardiotrophin-1 (CT-1), a cytokine that induces cardiomyocyte hypertrophy and stimulates cardiac fibroblasts, is related to hypertensive heart disease, as defined by the presence of echocardiographically assessed left ventricular hypertrophy (LVH).

METHODS

The study was performed in 31 normotensive subjects and 111 patients with never-treated essential hypertension (54 without LVH and 57 with LVH). Causes of LVH other than hypertension were excluded after a complete medical workup. A novel enzyme-linked immunosorbent assay was developed to measure plasma CT-1.

RESULTS

Plasma CT-1 was increased (P < 0.001) in hypertensives compared with normotensives. The value of CT-1 was higher (P < 0.001) in hypertensives with LVH than in hypertensives without LVH. Some 31% of patients without LVH exhibited values of CT-1 above the upper normal limit in normotensives. A direct correlation was found between CT-1 and left ventricular mass index (r = 0.319, P < 0.001) in all subjects. Receiver operating characteristic curves showed that a cutoff of 39 fmol/ml for CT-1 provided 75% specificity and 70% sensitivity for predicting LVH with a relative risk of 6.21 (95% confidence interval, 2.95 to 13.09).

CONCLUSIONS

These results show an association between LVH and the plasma concentration of CT-1 in essential hypertension. Although preliminary, these findings suggest that the determination of CT-1 may be an easy and reliable method for the initial screening and diagnosis of hypertensive heart disease.

Cardiotrophin-1 in choroid plexus and the cerebrospinal fluid circulatory system

There is a growing recognition of choroid plexus functioning as a source of neuropeptides, cytokines and growth factors in cerebrospinal fluid (CSF) with diffusional access into brain parenchyma. In this study, choroid plexus and other components of the CSF circulatory system were investigated by Western blotting, reverse transcriptase polymerase chain reaction and immunohistochemistry for production of interleukin-6-related cytokines characterized by neuroactivity [cardiotrophin-1 (CT-1), ciliary neurotrophic factor, leukemia inhibitory factor, oncostatin M] and signaling through the gp130/leukemia inhibitory factor receptor-beta receptor heterodimer. Western blot analysis showed that CT-1 was the only cytokine family member detectable in adult rat choroid plexus, as in leptomeninges. The specificity of detection was verified with blots of the same tissues from CT-1-deficient mice. Levels of both CT-1 mRNA and protein were constitutively high in rat from birth through adulthood in choroid plexus, up-regulated postnatally in leptomeninges and undetectable in brain parenchyma. Using antigen retrieval, CT-1 immunolocalized to choroid epithelial cells in all choroid plexuses in addition to leptomeninges (arachnoid and pial-glial membranes). Ependymal cells lining the ventricular neuroaxis, unlike the central canal, were also CT-1-immunoreactive. Western blots indicated rat choroid epithelial cells express and release CT-1 immunoreactivity under defined culture conditions and also revealed the presence of a CT-1-like protein in human choroid plexus and CSF. Previously, CT-1 has been conceptualized to function as a target-derived factor for PNS neurons. Our study clearly demonstrates production of CT-1 in the postnatal and adult CNS, specifically by cell types comprising the blood-CSF barrier, and its accumulation in ventricular ependyma. This finding has broad implications for CT-1 functioning apart from other leukemia inhibitory factor receptor ligands as a CSF-borne signal of brain homeostasis, one possibly involving regulation of the barrier itself, the ependyma or target cells in the surrounding parenchyma, including the subventricular zone. A rationale for studies examining CT-1-deficient mice in these respects is provided by the data.

Augmented expression of cardiotrophin-1 in failing human hearts is accompanied by diminished glycoprotein 130 receptor protein abundance

BACKGROUND

Cardiotrophin-1 (CT-1), a member of the interleukin-6 superfamily, is a potent inducer of cardiomyocyte hypertrophy that prolongs myocyte survival. Although cardiac CT-1 gene expression is known to be upregulated in some animal models of congestive heart failure, the activation state of the CT-1 system in patients with congestive heart failure is unknown.

METHODS AND RESULTS

This study was designed to determine left ventricular expression of CT-1 and its glycoprotein 130 (gp130)/leukemia inhibitory factor receptor complex in human end-stage heart failure due to ischemic and dilated cardiomyopathy. In addition, we investigated the activation state of signal transducer and activator of transcription 3 (STAT3), the downstream effector of gp130 signaling. In the failing left ventricular myocardium, expression levels of CT-1 mRNA and protein were significantly increased by 142% and 68%, respectively, compared with non-failing donor hearts. Immunohistochemistry confirmed the increased expression of CT-1 in cardiac myocytes. Although gp130 gene expression was increased by 91% (P<0.001), gp130 protein abundance was significantly diminished by 34% in the failing myocardium. In contrast, leukemia inhibitory factor receptor and suppressor of cytokine signaling-3 protein concentrations were not changed. In addition, the ratio of activated tyrosine phosphorylated STAT3 to total STAT3 was not significantly altered in failing hearts compared with non-failing controls.

CONCLUSIONS

Our data suggest that gp130 receptor downregulation balances enhanced CT-1 expression in human heart failure and thereby inhibits excessive activation of the gp130 signaling pathway.

Cardiotrophin-1 stimulates endothelin-1 via gp130 in vascular endothelial cells

Endothelin-1 (ET-1) is a vasoconstricting and mitogenic peptide released from vascular endothelial cells under normal and pathophysiological conditions, and synthesis and secretion of ET-1 are stimulated by cytokines. Cardiotrophin-1 (CT-1) is a new member of the interleukin-6-type cytokines that induce biological actions through the glycoprotein (gp) 130. The present study was designed to determine the presence of CT-1 and the gp130 cytokine system in vascular endothelial cells and to investigate whether CT-1 stimulates synthesis and secretion of ET-1 in the vascular endothelial cells. We first sought to determine gene expression and immunoreactivity of CT-1, gp130 and ET-1 in cultured canine aortic endothelial cells (CAECs) using Northern blot analysis and immunocytochemistry, which revealed the presence of CT-1 and gp130 together with ET-1 in CAECs. CT-1 increased ET-1 gene expression in CAECs, and stimulated ET-1 secretion from CAECs in a dose-dependent manner. Furthermore, inhibition of gp130 by monoclonal antibody attenuated ET-1 secretion from CAECs, suggesting that actions of CT-1 on the secretion of ET-1 are mediated through gp130 receptor system. The present study, therefore, reports the presence of CT-1 and gp130 in vascular endothelial cells and mechanisms of secretion of ET-1 related to this cytokine system.

Secretion of IL-6, IL-11 and LIF by human cardiomyocytes in primary culture

Interleukin (IL)-6-type cytokines are multifunctional proteins involved in cardiac hypertrophy and myocardial protection. Recent studies, performed on animal models, report the production of these cytokines by heart. The aim of this study was to analyse the capacity of myocytes and fibroblasts isolated from human atrium to secrete IL-6, leukaemia inhibitory factor (LIF), cardiotrophin-1 (CT-1), IL-11, oncostatin M (OSM), ciliary neurotrophic factor (CNTF) and the soluble receptor subunits sIL-6R and sgp130 during primary culture. We detected LIF, IL-11, sgp130 and a large amount of IL-6, but not OSM, CT-1, CNTF nor IL-6R in these culture supernatants. Both cardiomyocytes and fibroblasts are able to spontaneously produce IL-6. The increase of IL-6 production all along the culture period appears to be the consequence of fibroblast proliferation and gp130 stimulation. This is the first demonstration that human cardiac cells are able to secrete IL-6, but also LIF and IL-11 in vitro. These cytokines could be involved in an autocrine and/or a paracrine networks regulating myocardial cyto-protection, hypertrophy and fibrosis.

Relationship between plasma level of cardiotrophin-1 and left ventricular mass index in patients with dilated cardiomyopathy

OBJECTIVES

The study evaluated the relationship between plasma cardiotrophin-1 (CT-1) concentration and left ventricular (LV) mass in dilated cardiomyopathy (DCM) patients with congestive heart failure (CHF).

BACKGROUND

Cardiotrophin-1 is a newly identified member of the interleukin-6 (IL-6) family of cytokines and one of the endogenous ligands for gp130 signaling pathways in the heart, and it has potent hypertrophic and survival effects on cardiac myocytes. However, the clinical significance of CT-1 is poorly understood.

METHODS

We measured the plasma CT-1 level in 51 consecutive patients with DCM. Patients were classified into two groups: small LV mass index group and large LV mass index group, based on the median level of LV mass index.

RESULTS

The plasma CT-1 level was increased in DCM patients with the severity of CHF and was significantly higher in the large LV mass group than in the small LV mass group, despite the absence of a difference in LV ejection fraction between the two groups. In addition, there was a significant positive correlation between the plasma CT-1 level and the LV mass index (r = 0.627, p < 0.0001). According to stepwise multivariate analyses among hemodynamic and neurohumoral factors, a high plasma CT-1 level showed an independent and significant positive relationship with a large LV mass index in patients with DCM.

CONCLUSIONS

These results indicate that the plasma CT-1 level is increased in patients with DCM and is significantly correlated with the LV mass index, suggesting that CT-1 plays an important role in structural LV remodeling in patients with DCM.

Acute effect of human cardiotrophin-1 on hemodynamic parameters in spontaneously hypertensive rats and Wistar Kyoto rats

There is considerable evidence to indicate that humoral factors play an important role in the development of left ventricular hypertrophy. Cardiotrophin-1 (CT-1) is a cytokine that has been shown to induce cardiac hypertrophy in a dose-dependent manner. The aim of the present study was to investigate the acute effect of CT-1 on hemodynamic parameters in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) and to study the relationship between the plasma concentration of CT-1 and its hemodynamic effect. Ten-week-old SHR and age-matched WKY were used. Blood pressure (BP), heart rate (HR) and plasma concentration of CT-1 were measured both before and for 60 min after intravenous bolus injection of human CT-1 (10 microg/kg). CT-1 injection significantly decreased BP and significantly increased HR in SHR and WKY. There were significant differences in BP and HR between the two groups at all time points after injection. The lowest BP, highest HR and maximal plasma concentrations of CT-1 were observed in both groups within 10 min after injection. However, after converting the values into the percentage change from their respective baselines, there were no significant differences between the two groups in BP or HR at any time point. There was also no significant difference between the two groups at any time point in the plasma concentration of CT-1. This study indicates that CT-1 decreases BP and increases HR in both SHR and WKY. The most obvious change occurred within 10 min after injection. However, there was no significant difference in the hypotensive effect of CT-1 on 10-week-old SHR and WKY.

The cytoprotective effects of the glycoprotein 130 receptor-coupled cytokine, cardiotrophin-1, require activation of NF-kappa B

Many cell types mount elaborate, compensatory responses to stress that enhance survival; however, the intracellular signals that govern these responses are poorly understood. Cardiotrophin-1 (CT-1), a stress-induced cytokine, belongs to the interleukin-6/glycoprotein 130 receptor-coupled cytokine family. CT-1 is released from the heart in response to hypoxic stress, and it protects cardiac myocytes from hypoxia-induced apoptosis, thus establishing a central role for this cytokine in the cardiac stress response. In the present study, CT-1 activated p38 and ERK MAPKs as well as Akt in cultured cardiac myocytes; these three pathways were activated in a parallel manner. CT-1 also induced the degradation of the NF-kappa B cytosolic anchor, I kappa B, as well as the translocation of the p65 subunit of NF-kappa B to the nucleus and increased expression of an NF-kappa B-dependent reporter gene. Inhibitors of the p38, ERK, or Akt pathways each partially reduced CT-1-mediated NF-kappa B activation, as well as the cytoprotective effects of CT-1 against hypoxic stress. Together, the inhibitors completely blocked CT-1-dependent NF-kappa B activation and cytoprotection. A cell-permeable peptide that selectively disrupted NF-kappa B activation also completely inhibited the cytoprotective effects of CT-1. These results indicate that CT-1 signals through p38, ERK, and Akt in a parallel manner to activate NF-kappa B and that NF-kappa B is required for CT-1 to mediate its full cytoprotective effects in cardiac myocytes.