TGFβ1 and HGF regulate CTGF expression in human atrial fibroblasts and are involved in atrial remodelling in patients with rheumatic heart disease

The association of plasma connective tissue growth factor levels with left ventricular diastolic dysfunction in patients with overt hyperthyroidism

Background

Left ventricular (LV) diastolic dysfunction is an independent predictor of future cardiovascular events. Early detection of patients with LV diastolic dysfunction can improve clinical outcomes through active management. However, the assessment of diastolic function is very complicated, and there are currently lack of effective biomarkers to assess the risk of LV diastolic dysfunction. Connective tissue growth factor (CTGF) plays a significant role in cardiac remodeling and dysfunction. We aimed to investigate the associations between plasma CTGF level and the risk of LV diastolic dysfunction in this study and judge its effectiveness in diagnosing LV diastolic dysfunction.

Methods

A total of 169 patients with overt hyperthyroidism were included. LV diastolic function was evaluated and the subjects were divided into normal LV diastolic function group and LV diastolic dysfunction group. Routine clinical medical data, biochemical data, thyroid related parameters and echocardiographic parameters were recorded for analysis.

Results

Compared with normal LV diastolic function group, the LV diastolic dysfunction group had higher age and BMI, as well as lower heart rate, lower serum albumin, lower eGFR, higher serum TgAb and BNP level, and the incidences of hypertension were also higher (all P <0.05). Circulating plasma CTGF levels in the LV diastolic dysfunction group were significantly higher (normal LV diastolic function group: 7.026 [5.567-8.895], LV diastolic dysfunction group: 8.290 [7.054-9.225] ng/ml, median [(Interquartile range)], P = 0.004); Compared with the lowest quartile group, the crude odds ratios (OR) of LV diastolic dysfunction in the second, third, and fourth quartile group were 3.207, 5.032 and 4.554, respectively (all P<0.05). After adjustment for the potentially confounding variables, the adjusted OR values of the third and fourth quartile group had no obvious change. The results of ROC showed that the plasma CTGF had the largest area under the ROC curve, and the value was 0.659 (P = 0.005).

Conclusion

The level of circulating plasma CTGF in the LV diastolic dysfunction group was significantly increased. Plasma CTGF level is an independent risk factor for LV diastolic dysfunction. Compared with serum BNP level, the plasma CTGF level may have auxiliary diagnostic value for LV diastolic dysfunction in hyperthyroid patients.

Aerobic exercise protects MI heart through miR-133a-3p downregulation of connective tissue growth factor

OBJECTIVE

To investigate the effect of aerobic exercise intervention to inhibit cardiomyocyte apoptosis and thus improve cardiac function in myocardial infarction (MI) mice by regulating CTGF expression through miR-133a-3p.

METHODS

Male C57/BL6 mice, 7-8 weeks old, were randomly divided into sham-operated group (S group), sham-operated +aerobic exercise group (SE group), myocardial infarction group (MI group) and MI + aerobic exercise group (ME group). The mice were anesthetized the day after training and cardiac function was assessed by cardiac echocardiography. Myocardial collagen volume fraction (CVF%) was analyzed by Masson staining. Myocardial CTGF, Bax and Bcl-2 were detected by Western blotting, and myocardial miR-133a-3p was measured by RT-qPCR.

RESULTS

Compared with the S group, miR-133a-3p, Bcl-2 and EF were significantly decreased and CTGF, Bax, Bax/ Bcl-2, Caspase 3, Cleaved Caspase-3, LVIDd, LVIDs and CVF were significantly increased in the MI group. Compared with the MI group, miR-133a-3p, Bcl-2 and EF were significantly increased, cardiac function was significantly improved, and CTGF, Bax, Bax/ Bcl-2, Caspase 3, Cleaved Caspase-3, LVIDd, LVIDs and CVF were significantly decreased in ME group. The miR-133a-3p was significantly lower and CTGF was significantly higher in the H2O2 intervention group compared with the control group of H9C2 rat cardiomyocytes. miR-133a-3p was significantly higher and CTGF was significantly lower in the AICAR intervention group compared to the H2O2 intervention group. Compared with the control group of H9C2 rat cardiomyocytes, CTGF, Bax and Bax/Bcl-2 were significantly increased and Bcl-2 was significantly decreased in the miR-133a-3p inhibitor intervention group; CTGF, Bax and Bax/Bcl-2 were significantly decreased and Bcl-2 was significantly upregulated in the miR-133a-3p mimics intervention group.

CONCLUSION

Aerobic exercise down-regulated CTGF expression in MI mouse myocardium through miR-133a-3p, thereby inhibiting cardiomyocyte apoptosis and improving cardiac function.

Costunolide ameliorates angiotensin II-induced atrial inflammation and fibrosis by regulating mitochondrial function and oxidative stress in mice: A possible therapeutic approach for atrial fibrillation

Atrial fibrillation (AF) is a cardiac disease characterized by disordered atrial electrical activity. Atrial inflammation and fibrosis are involved in AF progression. Costunolide (COS) is a sesquiterpene lactone containing anti-inflammatory and anti-fibrotic activities. This study aims to explore the underlying mechanisms by which COS protects against AF. Male C57BL/6 mice (8- to 10-week-old) were infused with angiotensin (Ang) II for 3 weeks. Meanwhile, different doses of COS (COS-L: 10 mg/kg, COS-H: 20 mg/kg) were administered to mice by intragastric treatment. The results showed irregular and rapid heart rates in Ang II-treated mice. Moreover, the levels of inflammatory cytokines and fibrotic factors were elevated in mice. COS triggered a reduction of Ang II-induced inflammation and fibrosis, which conferred a protective effect. Mechanistically, mitochondrial dysfunction with mitochondrial respiration inhibition and aberrant ATP levels were observed after Ang II treatment. Moreover, Ang-II-induced excessive reactive oxygen species caused oxidative stress, which was further aggravated by inhibiting Nrf2 nuclear translocation. Importantly, COS diminished these Ang-II-mediated effects in mice. In conclusion, COS attenuated inflammation and fibrosis in Ang-II-treated mice by alleviating mitochondrial dysfunction and oxidative stress. Our findings represent a potential therapeutic option for AF treatment.

Developing Pharmacological Therapies for Atrial Fibrillation Targeting Mitochondrial Dysfunction and Oxidative Stress: A Scoping Review

Atrial fibrillation (AF) is a cardiac arrhythmia caused by electrophysiological anomalies in the atrial tissue, tissue degradation, structural abnormalities, and comorbidities. A direct relationship exists between AF and altered mitochondrial activity resulting from membrane potential loss, contractile dysfunction, or decreased ATP levels. This review aimed to elucidate the role of mitochondrial oxidative mechanisms in AF pathophysiology, the impact of mitochondrial oxidative stress on AF initiation and perpetuation, and current therapies. This review followed the Preferred Reporting Items for Systematic Reviews and the Meta-Analysis Extension for Scoping Reviews. PubMed, Excerpta Medica Database, and Scopus were explored until June 2023 using "MESH terms". Bibliographic references to relevant papers were also included. Oxidative stress is an imbalance that causes cellular damage from excessive oxidation, resulting in conditions such as AF. An imbalance in reactive oxygen species production and elimination can cause mitochondrial damage, cellular apoptosis, and cardiovascular diseases. Oxidative stress and inflammation are intrinsically linked, and inflammatory pathways are highly correlated with the occurrence of AF. AF is an intricate cardiac condition that requires innovative therapeutic approaches. The involvement of mitochondrial oxidative stress in the pathophysiology of AF introduces novel strategies for clinical treatment.

Neutrophil-Lymphocyte Ratio and Red Blood Cell Distribution Width in Patients with Atrial Fibrillation and Rheumatic Valve Disease

The lifetime risk of developing atrial fibrillation (AF) is 1 in 3 adults, resulting in a prevalence of 2-4%. Rheumatic heart disease (RHD) is a frequent aetiology of valvular heart disease in lowand middle-income countries. Between 21% and 80% of patients with mitral valve disease, especially with stenosis, may have AF. Both these conditions, AF and RHD, present a state of persistent inflammation. In turn, inflammation is a frequent cause of anisocytosis, which can be evidenced through the parameter RDW (red bold cell distribution width). Factors associated with increased RDW are also known as risk factors associated with a higher incidence of AF. RDW may have an independent role in the pathogenesis of AF and the increased propensity of both thromboembolic and bleeding events. Another marker involved in the incidence of AF is the neutrophil-lymphocyte ratio. This is also a marker of oxidative stress and inflammation and is associated with a higher rate of AF recurrence. This review will evaluate these biomarkers and their association with cardiovascular events in patients with AF and RHD. The hypotheses and current debates about the relationship of biomarkers with the severity of chronic valve dysfunction, with acute rheumatic carditis in the paediatric population, and with the presence of thrombus in the left atrium will be discussed.

[Serum levels of endothelin-1 and connective tissue growth factor are elevated in patients with atrial fibrillation and correlated with relapse following radiofrequency ablation]

OBJECTIVE

To investigate the changes in serum levels of endothelin-1 (ET-1) and connective tissue growth factor (CTGF) in patients with atrial fibrillation (AF) and their value for predicting recurrence of AF after radiofrequency ablation (RFCA).

METHODS

Sixty-six patients with paroxysmal AF (PaAF) and 72 with persistent AF (PaAF) admitted in our hospital were recruited as AF group and 80 patients with sinus rhythm as the control group, and in all the participants, serum levels of ET-1 and CTGF were measured using ELISA and Western blotting. From 6 patients with AF and 6 with sinus rhythm undergoing cardiac surgery in our hospital, tissue samples of the right atrial appendage were taken intraoperatively for observation of structural changes of the cardiomyocytes, myocardial fibrosis and expression of ET-1 and CTGF protein. In AF group, the patients receiving RFCA were followed up for 6 months following the procedure for assessment of the outcomes.

RESULTS

Compared with the control patients, the patients with AF showed obvious damages of the cardiomyocyte structure and myocardial fibrosis. Serum levels of ET-1 and CTGF levels were significantly higher in PaAF and PeAF groups than in the control group, and were higher in PeAF group than in PaAF group. In the patients with AF, serum ET-1 and CTGF levels were positively correlated with left atrial diameter (LAD) (P < 0.05), and ET-1 was positively correlated with CTGF levels (P < 0.05). In patients with postoperative AF recurrence, the serum levels of ET-1 and CTGF were significantly higher than those in patients without recurrence; serum ET-1 and CTGF levels before and after the operation were positively correlated with the recurrence of PeAF, and elevated serum levels of ET- 1 and CTGF were identified by logistic regression analysis as independent risk factors for postoperative recurrence of PeAF.

CONCLUSION

Serum levels of ET-1 and CTGF are significantly elevated in AF patients in positive correlation with AF duration. ET-1 and CTGF levels are higher in AF patients with postoperative recurrence, and they both have predictive value for recurrence of PeAF following RFCA.

The emerging role of leptin in obesity-associated cardiac fibrosis: evidence and mechanism

Cardiac fibrosis is a hallmark of various cardiovascular diseases, which is quite commonly found in obesity, and may contribute to the increased incidence of heart failure arrhythmias, and sudden cardiac death in obese populations. As an endogenous regulator of adiposity metabolism, body mass, and energy balance, obesity, characterized by increased circulating levels of the adipocyte-derived hormone leptin, is a critical contributor to the pathogenesis of cardiac fibrosis. Although there are some gaps in our knowledge linking leptin and cardiac fibrosis, this review will focus on the interplay between leptin and major effectors involved in the pathogenesis underlying cardiac fibrosis at both cellular and molecular levels based on the current reports. The profibrotic effect of leptin is predominantly mediated by activated cardiac fibroblasts but may also involve cardiomyocytes, endothelial cells, and immune cells. Moreover, a series of molecular signals with a known profibrotic property is closely involved in leptin-induced fibrotic events. A more comprehensive understanding of the underlying mechanisms through which leptin contributes to the pathogenesis of cardiac fibrosis may open up a new avenue for the rapid emergence of a novel therapy for preventing or even reversing obesity-associated cardiac fibrosis.

Extracellular ATP promotes angiogenesis and adhesion of TNBC cells to endothelial cells via up-regulation of CTGF

Our previous works have indicated that extracellular ATP is an important prometastasis factor. However, the molecular mechanism involved needs to be further studied. We demonstrated that extracellular ATP treatment could upregulate the expression of connective tissue growth factor (CTGF) in both triple‐negative breast cancer (TNBC) cells and endothelial cells (ECs). Extracellular ATP stimulated the migration of TNBC cells and ECs, and angiogenesis of ECs via the P2Y2––YAP‐CTGF axis. Furthermore, we demonstrated that adenosine triphosphate (ATP) stimulated TNBC cell adhesion to ECs and transmigration through the EC layer via CTGF by upregulation of integrin β1 on TNBC cells and VCAM‐1 on ECs. Both apyrase (ATP‐diphosphohydrolase) and CTGF shRNA treatments could inhibit the metastasis of inoculated tumors to lung and liver in a mouse model, and these treated tumors had fewer blood vessels. Collectively, our data indicated that extracellular ATP promotes tumor angiogenesis and the interactions between TNBC cells and ECs through upregulation of CTGF, thereby stimulating TNBC metastasis. The pleiotropic effects of ATP in angiogenesis and cell adhesion suggest that extracellular ATP or CTGF could be an effective target for TNBC therapy.

Isolation and characterization mesenchymal stem cells from red panda (Ailurus fulgens styani) endometrium

Endometrial mesenchymal stem cells (eMSCs) are undifferentiated endometrial cells with self-renewal, multidirectional differentiation and high proliferation potential. Nowadays, eMSCs have been found in a few species, but it has never been reported in endangered wild animals, especially the red panda. In this study, we successfully isolated and characterized the eMSCs derived from red panda. Red panda eMSCs were fibroblast-like, had a strong proliferative potential and a stable chromosome number. Pluripotency genes including Klf4, Sox2 and Thy1 were highly expressed in eMSCs. Besides, cultured eMSCs were positive for MSC markers CD44, CD49f and CD105 and negative for endothelial cell marker CD31 and haematopoietic cell marker CD34. Moreover, no reference RNA-seq was used to analyse the eMSCs transcriptional expression profile and key pathways. Compared with skin fibroblast cell group, 9104 differentially expressed genes (DEGs) were identified, among which are 5034 genes upregulated, 4070 genes downregulated and the top 20 enrichment pathways of DEGs in Gene Ontology (GO) and the Kyoto Encyclopedia of Genes Genomes (KEGG) mainly associated with G-protein coupled receptor signalling pathway, carbohydrate derivative binding, nucleoside binding, ribosome biogenesis, cell cycle, DNA replication, Ras signalling pathway and purine metabolism. Among the DEGs, some representative genes about promoting MSCs differentiation and proliferation were upregulated and promoting fibroblasts proliferation were downregulated in eMSCs group. Red panda eMSCs also had multiple differentiation ability and could differentiate into adipocytes, chondrocytes and hepatocytes. In conclusion, we, for the first time, isolated and characterized the red panda eMSCs with ability of multiplication and multilineage differentiation in vitro. The new multipotential stem cell could be beneficial not only for the germ plasm resources conservation of red panda, but also for basic or pre-clinical studies in the future.

Atractylenolide-I Sensitizes Triple-Negative Breast Cancer Cells to Paclitaxel by Blocking CTGF Expression and Fibroblast Activation

This investigation was conducted to elucidate whether atractylenolide-I (ATL-1), which is the main component of Atractylodes macrocephala Koidz, can sensitize triple-negative breast cancer (TNBC) cells to paclitaxel and investigate the possible mechanism involved. We discovered that ATL-1 could inhibit tumor cell migration and increase the sensitivity of tumor cells to paclitaxel. ATL-1 downregulated the expression and secretion of CTGF in TNBC cells. Apart from inhibiting TNBC cell migration via CTGF, ATL-1 downregulated the expression of CTGF in fibroblasts and decreased the ability of breast cancer cells to transform fibroblasts into cancer-associated fibroblasts (CAFs), which in turn increased the sensitivity of TNBC cells to paclitaxel. In a mouse model, we found that ATL-1 treatments could enhance the chemotherapeutic effect of paclitaxel on tumors and reduce tumor metastasis to the lungs and liver. Primary cultured fibroblasts derived from inoculated tumors in mice treated with ATL-1 combined with paclitaxel expressed relatively low levels of CAF markers. Collectively, our data indicate that ATL-1 can sensitize TNBC cells to paclitaxel by blocking CTGF expression and fibroblast activation and could be helpful in future research to determine the value of ATL-1 in the clinical setting.

Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review

The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here.

Association of Plasma Connective Tissue Growth Factor Levels with Hyperthyroid Heart Disease

Hyperthyroid heart disease (HHD) is one of the most severe complications of overt hyperthyroidism and increases the risk of mortality in affected patients. Early identification of patients at a higher risk of developing HHD can improve clinical outcomes through active surveillance and management. Connective tissue growth factor (CTGF), a secreted extracellular protein, plays a significant role in cardiac remodeling and dysfunction. We aimed to investigate the association between plasma CTGF level and the risk of HHD in this study. A total of 142 overt hyperthyroid patients without HHD and 99 patients with HHD were included. The plasma CTGF levels were measured using ELISA kits. Routine clinical medical data and echocardiography parameters were recorded for analysis. The plasma CTGF level was significantly higher in patients with HHD than in those without HHD (P=0.002). The plasma CTGF level was positively correlated with free triiodothyronin, tryrotropin receptor antibody, troponin I and lactate dehydrogenase levels and the left atrium diameters, right atrium diameters, and right ventricular end-diastolic diameters (all P<0.05). Logistic regression analysis showed that quartiles 3 and 4 of plasma CTGF levels were significantly associated with the increased risk of HHD (crude OR: 2.529; 95% CI: 1.188-5.387). However, after adjustment for the potentially confounding variables, quartile 4 alone was significantly associated with the higher risk of HHD relative to quartile 1. Hyperthyroid patients with HHD display higher plasma CTGF levels. Furthermore, CTGF is an independent risk factor for HHD. Therefore, the plasma CTGF level may be a potential biomarker for the risk of HHD.

Identification of Common Genes and Pathways in Eight Fibrosis Diseases

Acute and chronic inflammation often leads to fibrosis, which is also the common and final pathological outcome of chronic inflammatory diseases. To explore the common genes and pathogenic pathways among different fibrotic diseases, we collected all the reported genes of the eight fibrotic diseases: eye fibrosis, heart fibrosis, hepatic fibrosis, intestinal fibrosis, lung fibrosis, pancreas fibrosis, renal fibrosis, and skin fibrosis. We calculated the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment scores of all fibrotic disease genes. Each gene was encoded using KEGG and GO enrichment scores, which reflected how much a gene can affect this function. For each fibrotic disease, by comparing the KEGG and GO enrichment scores between reported disease genes and other genes using the Monte Carlo feature selection (MCFS) method, the key KEGG and GO features were identified. We compared the gene overlaps among eight fibrotic diseases and connective tissue growth factor (CTGF) was finally identified as the common key molecule. The key KEGG and GO features of the eight fibrotic diseases were all screened by MCFS method. Moreover, we interestingly found overlaps of pathways between renal fibrosis and skin fibrosis, such as GO:1901890-positive regulation of cell junction assembly, as well as common regulatory genes, such as CTGF, which is the key molecule regulating fibrogenesis. We hope to offer a new insight into the cellular and molecular mechanisms underlying fibrosis and therefore help leading to the development of new drugs, which specifically delay or even improve the symptoms of fibrosis.

25-OH-PPD inhibits hypertrophy on diabetic cardiomyopathy via the PI3k/Akt/GSK-3β signaling pathway

The present study investigated the inhibitory effects and the associated mechanism of the compound 25-OH-PPD (PPD) on cardiac hypertrophy, fibrosis and inflammation. The signaling pathways associated with diabetic mellitus cardiomyopathy (DMCM) were investigated using a rat model. DMCM Sprague-Dawley rats were induced by injection of streptozotocin. The animals were divided into 5 groups as follows: Normal group (NG group), diabetic group, PPD treatment group, PPD/LY294002 group (inhibitor of PI3K/Akt) and PPD/LiCl group [inhibitor of glycogen synthase kinase (GSK) 3β]. The studies were carried out during the 12 weeks following induction of diabetes and the levels of plasma brain natriuretic peptide (BNP), creatine phosphokinase isoenzyme (CK-MB) were measured. In addition, the volume of myocardial collagen fraction (CVF) was tested. The expression levels of the inflammatory cytokines, including transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), cell adhesion molecules α-smooth muscle actin (α-SMA) and vascular adhesion molecule 1 (VCAM-1) and associated signaling proteins (Akt, GSK-3β) were measured by biochemical analyses. The levels of BNP and CK-MB, the volume of CVF, the expression levels of TGF-β1, CTGF, α-SMA and VCAM-1 in the diabetic group were higher compared with those of the normal control group (P<0.05). Conversely, the levels of these molecules were significantly decreased in the PPD treatment groups (P<0.05). The aforementioned effects were partially eliminated in the PPD/LY294002 and PPD/LiCl groups. In addition, PPD treatment significantly increased the expression levels of p-Akt and decreased the levels of phosphorylated GSK-3β compared with those of the DMCM group (P<0.05). The data demonstrated that the protective effects of 25-OH-PPD against DMCM may be attributed to the PI3k/Akt/GSK-3β signaling pathway, via the suppression of the α-SMA/VCAM axis and the downregulation of TGF-β1 and CTGF expression.

Role of activin receptor-like kinase 1 in vascular development and cerebrovascular diseases

Activin receptor-like kinase 1 (ALK1) is a transmembrane serine/threonine receptor kinase of the transforming growth factor beta (TGFβ) receptor superfamily. ALK1 is specifically expressed in vascular endothelial cells, and its dynamic changes are closely related to the proliferation of endothelial cells, the recruitment of pericytes to blood vessels, and functional differentiation during embryonic vascular development. The pathophysiology of many cerebrovascular diseases is today understood as a disorder of endothelial cell function and an imbalance in the proportion of vascular cells. Indeed, mutations in ALK1 and its co-receptor endoglin are major genetic risk factors for vascular arteriovenous malformation. Many studies have shown that ALK1 is closely related to the development of cerebral aneurysms, arteriovenous malformations, and cerebral atherosclerosis. In this review, we describe the various roles of ALK1 in the regulation of angiogenesis and in the maintenance of cerebral vascular homeostasis, and we discuss its relationship to functional dysregulation in cerebrovascular diseases. This review should provide new perspectives for basic research on cerebrovascular diseases and offer more effective targets and strategies for clinical diagnosis, treatment, and prevention.

TGFβ1 and HGF regulate CTGF expression in human atrial fibroblasts and are involved in atrial remodelling in patients with rheumatic heart disease

OBJECTIVE

This study aimed to investigate the effects of transforming growth factor β1 (TGF β1) and hepatocyte growth factor (HGF) on the expression of connective tissue growth factor (CTGF) in human atrial fibroblasts, and to explore the relationship of these factors in atrial fibrosis and atrial anatomical remodelling (AAR) of patients with atrial fibrillation (AF).

METHODS

Fresh right auricular appendix tissue of 20 patients with rheumatic heart disease undergoing valve replacement surgery was collected during surgeries, 10 patients had sinus rhythm(SR), and 10 patients had chronic atrial fibrillation (CAF). Atrial fibroblasts were then cultured from the tissues with differential attachment technique and treated with either TGFβ1 (10 ng/mL) or HGF (100 ng/mL). CTGF mRNA levels were measured by RT-PCR, and CTGF protein content was determined using immunofluorescence and Western blotting assays.

RESULTS

CAF group had higher left atrial diameters (LADs) and higher CTGF mRNA expression in atrial fibroblasts compared with SR group. The CTGF protein content in CAF group was higher than that of SR group and positively correlated with LAD and AF duration. After CAF group was treated with TGFβ1, CTGF mRNA and protein expression were significantly down-regulated, whereas when treated with HGF, expression was up-regulated compared with SR group.

CONCLUSIONS

Increased CTGF expression was associated with enlarged LAD, atrial fibrosis and AAR in patients with AF. TGFβ1 and HGF regulate CTGF expression in human atrial fibroblasts with up-regulation of mRNA and down-regulation of protein, therefore, either promote or inhibit atrial fibrosis, which could be related to the incidence and persistence of AF.