Profibrotic VEGFR3-Dependent Lymphatic Vessel Growth in Autoimmune Valvular Carditis

BACKGROUND

Rheumatic heart disease is the major cause of valvular heart disease in developing nations. Endothelial cells (ECs) are considered crucial contributors to rheumatic heart disease, but greater insight into their roles in disease progression is needed.

METHODS

We used a Cdh5-driven EC lineage-tracing approach to identify and track ECs in the K/B.g7 model of autoimmune valvular carditis. Single-cell RNA sequencing was used to characterize the EC populations in control and inflamed mitral valves. Immunostaining and conventional histology were used to evaluate lineage tracing and validate single-cell RNA-sequencing findings. The effects of VEGFR3 (vascular endothelial growth factor receptor 3) and VEGF-C (vascular endothelial growth factor C) inhibitors were tested in vivo. The functional impact of mitral valve disease in the K/B.g7 mouse was evaluated using echocardiography. Finally, to translate our findings, we analyzed valves from human patients with rheumatic heart disease undergoing mitral valve replacements.

RESULTS

Lineage tracing in K/B.g7 mice revealed new capillary lymphatic vessels arising from valve surface ECs during the progression of disease in K/B.g7 mice. Unsupervised clustering of mitral valve single-cell RNA-sequencing data revealed novel lymphatic valve ECs that express a transcriptional profile distinct from other valve EC populations including the recently identified PROX1 (Prospero homeobox protein 1)+ lymphatic valve ECs. During disease progression, these newly identified lymphatic valve ECs expand and upregulate a profibrotic transcriptional profile. Inhibiting VEGFR3 through multiple approaches prevented expansion of this mitral valve lymphatic network. Echocardiography demonstrated that K/B.g7 mice have left ventricular dysfunction and mitral valve stenosis. Valve lymphatic density increased with age in K/B.g7 mice and correlated with worsened ventricular dysfunction. Importantly, human rheumatic valves contained similar lymphatics in greater numbers than nonrheumatic controls.

CONCLUSIONS

These studies reveal a novel mode of inflammation-associated, VEGFR3-dependent postnatal lymphangiogenesis in murine autoimmune valvular carditis, with similarities to human rheumatic heart disease.

Prothymosin Alpha: A Novel Contributor to Estradiol Receptor Alpha-Mediated CD8+ T-Cell Pathogenic Responses and Recognition of Type 1 Collagen in Rheumatic Heart Valve Disease

BACKGROUND

Rheumatic heart valve disease (RHVD) is a leading cause of cardiovascular death in low- and middle-income countries and affects predominantly women. The underlying mechanisms of chronic valvular damage remain unexplored and regulators of sex predisposition are unknown.

METHODS

Proteomics analysis of human heart valves (nondiseased aortic valves, nondiseased mitral valves [NDMVs], valves from patients with rheumatic aortic valve disease, and valves from patients with rheumatic mitral valve disease; n=30) followed by system biology analysis identified ProTα (prothymosin alpha) as a protein associated with RHVD. Histology, multiparameter flow cytometry, and enzyme-linked immunosorbent assay confirmed the expression of ProTα. In vitro experiments using peripheral mononuclear cells and valvular interstitial cells were performed using multiparameter flow cytometry and quantitative polymerase chain reaction. In silico analysis of the RHVD and Streptococcuspyogenes proteomes were used to identify mimic epitopes.

RESULTS

A comparison of NDMV and nondiseased aortic valve proteomes established the baseline differences between nondiseased aortic and mitral valves. Thirteen unique proteins were enriched in NDMVs. Comparison of NDMVs versus valves from patients with rheumatic mitral valve disease and nondiseased aortic valves versus valves from patients with rheumatic aortic valve disease identified 213 proteins enriched in rheumatic valves. The expression of the 13 NDMV-enriched proteins was evaluated across the 213 proteins enriched in diseased valves, resulting in the discovery of ProTα common to valves from patients with rheumatic mitral valve disease and valves from patients with rheumatic aortic valve disease. ProTα plasma levels were significantly higher in patients with RHVD than in healthy individuals. Immunoreactive ProTα colocalized with CD8⁺ T cells in RHVD. Expression of ProTα and estrogen receptor alpha correlated strongly in circulating CD8⁺ T cells from patients with RHVD. Recombinant ProTα induced expression of the lytic proteins perforin and granzyme B by CD8⁺ T cells as well as higher estrogen receptor alpha expression. In addition, recombinant ProTα increased human leukocyte antigen class I levels in valvular interstitial cells. Treatment of CD8⁺ T cells with specific estrogen receptor alpha antagonist reduced the cytotoxic potential promoted by ProTα. In silico analysis of RHVD and Spyogenes proteomes revealed molecular mimicry between human type 1 collagen epitope and bacterial collagen-like protein, which induced CD8⁺ T-cell activation in vitro.

CONCLUSIONS

ProTα-dependent CD8⁺ T-cell cytotoxicity was associated with estrogen receptor alpha activity, implicating ProTα as a potential regulator of sex predisposition in RHVD. ProTα facilitated recognition of type 1 collagen mimic epitopes by CD8⁺ T cells, suggesting mechanisms provoking autoimmunity.

Innate and adaptive immunity: the understudied driving force of heart valve disease

Calcific aortic valve disease (CAVD), and its clinical manifestation that is calcific aortic valve stenosis, is the leading cause for valve disease within the developed world, with no current pharmacological treatment available to delay or halt its progression. Characterized by progressive fibrotic remodelling and subsequent pathogenic mineralization of the valve leaflets, valve disease affects 2.5% of the western population, thus highlighting the need for urgent intervention. Whilst the pathobiology of valve disease is complex, involving genetic factors, lipid infiltration, and oxidative damage, the immune system is now being accepted to play a crucial role in pathogenesis and disease continuation. No longer considered a passive degenerative disease, CAVD is understood to be an active inflammatory process, involving a multitude of pro-inflammatory mechanisms, with both the adaptive and the innate immune system underpinning these complex mechanisms. Within the valve, 15% of cells evolve from haemopoietic origin, and this number greatly expands following inflammation, as macrophages, T lymphocytes, B lymphocytes, and innate immune cells infiltrate the valve, promoting further inflammation. Whether chronic immune infiltration or pathogenic clonal expansion of immune cells within the valve or a combination of the two is responsible for disease progression, it is clear that greater understanding of the immune systems role in valve disease is required to inform future treatment strategies for control of CAVD development.

Contemporary Diagnosis and Management of Rheumatic Heart Disease: Implications for Closing the Gap: A Scientific Statement From the American Heart Association

The global burden of rheumatic heart disease continues to be significant although it is largely limited to poor and marginalized populations. In most endemic regions, affected patients present with heart failure. This statement will seek to examine the current state-of-the-art recommendations and to identify gaps in diagnosis and treatment globally that can inform strategies for reducing disease burden. Echocardiography screening based on World Heart Federation echocardiographic criteria holds promise to identify patients earlier, when prophylaxis is more likely to be effective; however, several important questions need to be answered before this can translate into public policy. Population-based registries effectively enable optimal care and secondary penicillin prophylaxis within available resources. Benzathine penicillin injections remain the cornerstone of secondary prevention. Challenges with penicillin procurement and concern with adverse reactions in patients with advanced disease remain important issues. Heart failure management, prevention, early diagnosis and treatment of endocarditis, oral anticoagulation for atrial fibrillation, and prosthetic valves are vital therapeutic adjuncts. Management of health of women with unoperated and operated rheumatic heart disease before, during, and after pregnancy is a significant challenge that requires a multidisciplinary team effort. Patients with isolated mitral stenosis often benefit from percutaneous balloon mitral valvuloplasty. Timely heart valve surgery can mitigate the progression to heart failure, disability, and death. Valve repair is preferable over replacement for rheumatic mitral regurgitation but is not available to the vast majority of patients in endemic regions. This body of work forms a foundation on which a companion document on advocacy for rheumatic heart disease has been developed. Ultimately, the combination of expanded treatment options, research, and advocacy built on existing knowledge and science provides the best opportunity to address the burden of rheumatic heart disease.

The American Heart Association's Call to Action for Reducing the Global Burden of Rheumatic Heart Disease: A Policy Statement From the American Heart Association

Rheumatic heart disease (RHD) affects ≈40 million people and claims nearly 300 000 lives each year. The historic passing of a World Health Assembly resolution on RHD in 2018 now mandates a coordinated global response. The American Heart Association is committed to serving as a global champion and leader in RHD care and prevention. Here, we pledge support in 5 key areas: (1) professional healthcare worker education and training, (2) technical support for the implementation of evidence-based strategies for rheumatic fever/RHD prevention, (3) access to essential medications and technologies, (4) research, and (5) advocacy to increase global awareness, resources, and capacity for RHD control. In bolstering the efforts of the American Heart Association to combat RHD, we hope to inspire others to collaborate, communicate, and contribute.

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.

Presence of increased inflammatory infiltrates accompanied by activated dendritic cells in the left atrium in rheumatic heart disease

Aims

Left atrial (LA) structural remodelling develops in rheumatic heart disease (RHD) according to the disease severity of the mitral valve and the presence of atrial fibrillation. Sustained active inflammation has been previously reported in the LA of patients with RHD, suggesting a direct role of cell-mediated immunity in the pathogenesis of LA remodelling. Dendritic cells (DCs) have a major antigen-presenting role, and are known as crucial modulators of innate and adaptive immunity. We investigated whether DCs are involved in the pathogenesis of LA remodelling in RHD.

Methods and results

Immunohistochemical analyses were performed using antibodies to CD11c, CD209 and CD80 as markers of myeloid DCs, migratory-active DCs, mature DCs and infiltrated inflammatory cells including T lymphocytes (CD3) and M1 (CD68; pro-inflammatory profile) and M2 (CD163; pro-resolution profile) macrophages. Furthermore, tenascin-C, an extracellular matrix (ECM) protein that appears during ECM remodelling and inflammatory response, was examined. Infiltrated myeloid DCs, migratory-active DCs, mature DCs and other inflammatory infiltrates including T lymphocytes and M1 and M2 macrophages, were significantly higher in the RHD group than the non-RHD group. The positive area fraction for tenascin-C was significantly higher in the RHD group than in the non-RHD group.

Conclusion

Our histological findings suggest that inflammation may persist long after a bout of rheumatic fever, ultimately leading to ECM remodelling. We identified and quantitatively assessed several subsets of DCs and other immunocompetent cells, and our results indicated that activation of DCs has some role in persistence of LA inflammation in patients with chronic RHD.

Oncostatin M was associated with thrombosis in patients with atrial fibrillation

The mechanism underlying thrombosis in atrial fibrillation (AF) is not yet clearly understood. Oncostatin M (OSM), as a member of IL-6 family, is involved in atherosclerosis-mediated thrombosis. The present study hypothesizes that OSM and its downstream factors play a role in thrombogenesis in AF.The specimens of left atrial appendages collected from patients with rheumatic mitral stenosis who underwent valve replacement were divided into 3 groups: sinus rhythm, AF(+)/thrombus(-), and AF(+)/thrombus(+) group. The macrophage infiltration in atrial tissue was assessed by immunohistochemistry, and the amount of OSM, tissue factor (TF), and tissue factor pathway inhibitors (TFPIs) was detected by Western blot.The infiltration of the M1 macrophages was significantly increased in the AF with thrombus group compared with the sinus rhythm group (P = .03). Moreover, the expression of OSM and TF was much higher in the AF with thrombus group compared with the sinus rhythm group (P = .02, .009, respectively) while the TFPI was decreased in the AF with thrombus group (P = .04).OSM might be correlated with thrombosis in patients with AF mediated by TF and TFPI.

Rheumatic Heart Disease and Myxomatous Degeneration: Differences and Similarities of Valve Damage Resulting from Autoimmune Reactions and Matrix Disorganization

Autoimmune inflammatory reactions leading to rheumatic fever (RF) and rheumatic heart disease (RHD) result from untreated Streptococcus pyogenes throat infections in individuals who exhibit genetic susceptibility. Immune effector mechanisms have been described that lead to heart tissue damage culminating in mitral and aortic valve dysfunctions. In myxomatous valve degeneration (MXD), the mitral valve is also damaged due to non-inflammatory mechanisms. Both diseases are characterized by structural valve disarray and a previous proteomic analysis of them has disclosed a distinct profile of matrix/structural proteins differentially expressed. Given their relevance in organizing valve tissue, we quantitatively evaluated the expression of vimentin, collagen VI, lumican, and vitronectin as well as performed immunohistochemical analysis of their distribution in valve tissue lesions of patients in both diseases. We identified abundant expression of two isoforms of vimentin (45 kDa, 42 kDa) with reduced expression of the full-size protein (54 kDa) in RHD valves. We also found increased vitronectin expression, reduced collagen VI expression and similar lumican expression between RHD and MXD valves. Immunohistochemical analysis indicated disrupted patterns of these proteins in myxomatous degeneration valves and disorganized distribution in rheumatic heart disease valves that correlated with clinical manifestations such as valve regurgitation or stenosis. Confocal microscopy analysis revealed a diverse pattern of distribution of collagen VI and lumican into RHD and MXD valves. Altogether, these results demonstrated distinct patterns of altered valve expression and tissue distribution/organization of structural/matrix proteins that play important pathophysiological roles in both valve diseases.

[Significance and Expressions of MMP-1, TIMP-1 and TGF-β1 in Valve Tissue of Rheumatic Heart Disease]

OBJECTIVES

To explore expressions of matrix metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinases-1 (TIMP-1) and transforming growth factor-β1 (TGF-β1) in valve tissue of rheumatic heart disease (RHD), and to analyzed their roles in RHD.

METHODS

The expressions of MMP-1, TIMP-1 and TGF-β1 proteins and mRNAs were tested by Western blot and RT-PCR methods in valve tissues in participants with (experimental group, n=30) and without RHD (control group, n=15). Collagen fibers were detected by Masson staining, and collagen volume fraction (CVF) was caculated. The correlations of CVF and the expressions of MMP-1, TIMP-1 and TGF-β1 were analyzed.

RESULTS

The collagen fibers, CVF, and the protein and mRNA expressions of MMP-1 and TGF-β1 in experimental group were higher than those in control group, while the protein and mRNA expressions of TIMP-1 in experimental group were lower than those in control group. The expression of TIMP-1 was negatively correlated with TGF-β1 and CVF in valve tissues, while MMP-1 was positively correlated with them. The expression of TGF-β1 was positively correlated with CVF in valve tissues.

CONCLUSIONS

MMP-1, TIMP-1 and TGF-β1 contribute to the progression of fibrosis in RHD.

Functional role of NKX2-5 and Smad6 expression in developing rheumatic heart disease

OBJECTIVE

Rheumatic heart disease (RHD) results due to the cross reaction of the host immune system when it develops immunity against group A streptococcal infection. This autoimmune disease progress with different pathological conditions and the genes associated with it are still less understood.

MATERIALS AND METHODS

To understand the role of NKX2-5 and Smad-6 in developing an RHD, we successfully developed RHD model using BALB/c mice and we evaluate the expression of NKX2-5 and Smad-6 in different conditions.

RESULTS

The disease conditions are confirmed through histological sectioning of RHD heart tissue with its associated Aschoff bodies. The histological of control heart tissue in the absence of NKX2-5 looks abnormal with an enlarged nucleus and in the absence of Smad-6 the solid nature of heart tissue loosens. The mice developed a complex form of acute RHD with tissue hardening in the absence of either NKX2-5 or Smad-6 which are confirmed in NKX2-5 or Smad-6 null mice. Immunohistochemical studies reveal that the NKX2-5 and Smad-6 expression get down regulated on developing with RHD. Through experiments, we detected that both Nkx2-5 and Smad-6 are both inter-dependable and it negatively regulated each other by inhibiting them. In the absence of NKX2-5 or Smad-6, a severe form of RHD is observed together with down-regulation of either NKX2-5 or Smad-6.

CONCLUSIONS

The present investigation of NKX2-5 and Smad-6 in RHD provides a new insight of data that helps to understand the disease pathogenesis.

Proteomic analysis of mitral valve in Lewis rat with acute rheumatic heart disease

Rheumatic heart disease (RHD) makes a heavy burden in human lives and economy. The proteomic analysis of acute rheumatic heart disease (ARHD) can provide precious data to study RHD at the early stages, but no one has looked into. So based on our early research we applied the method of continuous GAS stimulation on Lewis rats to duplicate the animal model of ARHD. And the mitral valves of rats in control group (n=10) and ARHD group (n=10) were selected for proteomic analysis of ARHD with the iTRAQ labeling based 2D LC-ESI-MS/MS quantitative technology. We identified 3931 proteins in valve tissue out of which we obtained 395 differentially expressed proteins containing 176 up-regulated proteins and 119 down-regulated proteins. Changes in levels of GAPDH (6.793 times higher than the control group) and CD9 (2.63 times higher than the control group) were confirmed by Western blot or immunohistochemistry. The differentially expressed proteins such as GAPDH, CD9, myosin, collagen and RAC1 may be potential biomarkers for ARHD. Moreover, the mitral valve protein profile shed light on further understanding and investigating ARHD.

TGF-β1 and TIMP-4 regulate atrial fibrosis in atrial fibrillation secondary to rheumatic heart disease

To investigate the involvement of transforming growth factor-β1 (TGF-β1) and tissue inhibitor of metalloproteinase 4 (TIMP-4) in influencing the severity of atrial fibrosis in rheumatic heart disease (RHD) patients with atrial fibrillation (AF). The degree of myocardial fibrosis was evaluated using Masson staining. The expression levels of TGF-β1, TIMP-4, matrix metalloproteinase-2 (MMP-2), type I collagen, and type III collagen were estimated by Western blot analysis. Additionally, TGF-β1 and TIMP-4 mRNA levels were quantified by qRT-PCR. The effect of TGF-β1 stimulation on TIMP-4 expression was assessed by in vitro stimulation of freshly isolated human atrial fibroblasts with recombinant human TGF-β1, followed by Western blot analysis to detect changes in TIMP-4 levels. Masson stain revealed that the left atrial diameter and collagen volume fraction were obviously increased in AF patients, compared to sinus rhythm (SR) controls (both P < 0.05). Western blot analysis showed significantly elevated levels of the AF markers MMP-2, type I collagen, and type III collagen in the AF group, in comparison to the SR controls (all P < 0.05). In the AF group, TGF-β1 expression was relatively higher, while TIMP-4 expression was apparently lower than the SR group (all P < 0.05). TIMP-4 expression level showed a negative association with TGF-β1 expression level (r = -0.98, P < 0.01) and TGF-β1 stimulation of atrial fibroblasts led to a sharp decrease in TIMP-4 protein level. Increased TGF-β1 expression and decreased TIMP-4 expression correlated with atrial fibrosis and ECM changes in the atria of RHD patients with AF. Notably, TGF-β1 suppressed TIMP-4 expression, suggesting that selective TGF-β1 inhibitors may be useful therapeutic agents.

[Impacts on oxidative stress in the patients with cardiac valve replacement treated with electroacupuncture at Neiguan (PC 6)]

OBJECTIVE

To observe the myocardial protective effect of electroacupuncture (EA) at Neiguan (PC 6) in the patients with valve replacement via extracorporeal circulation.

METHODS

Fifty patients of rheumatic cardiac disease planned for valve replacement were graded as II or III level according to America Society of Anesthesiologists (ASA) and were randomized into an observation group and a control group, 25 cases in each one. The same anesthesia and valve replacement via extracorporeal circulation were adopted in the patients of the two groups. In the observation group, 30 min before operation, EA was used to stimulate bilateral Neiguan (PC 6) till the end of operation. The venous blood was collected at 5 time points separately, named before aorta blockage (T1), 15 min after aorta open (T2), 30 min after aorta open (T3), 6 h after opening (T4) and 24 h after opening (T5). The concentrations of malondial dehyde (MDA), superoxide dismutase (SOD) and cardiac troponin 1 (cTnI) were determined in serum. The heart re-beating and the total dosage of vasoactive drugs after operation were recorded.

RESULTS

Compared with those before aorta blockage, MDA and cTnI at each time point of aorta open were all apparently increased in the patients of the two groups (all P<0. 05), and SOD was reduced apparently (P<0. 05). Compared with the control group, at the time points from T3 to T5 , MDA and cTnL were lower apparently in the observation group as compared with those in the control group (all P<0. 05) and SOD was higher than that in the control group (P<0. 05). The dosage of vasoactive drugs was reduced apparently (P<. 05).

CONCLUSION

EA at Neiguan (PC 6) alleviates oxidative stress injury and has the protective effect on ischemic reperfusion myocardium.

Increased TRPM6 expression in atrial fibrillation patients contribute to atrial fibrosis

BACKGROUND

Transient receptor potential (TRP) family plays important roles in cardiovascular system. We investigated the relationship between transient receptor potential channel subfamily M6 (TRPM6) and atrial fibrosis in rheumatic heart disease patients with atrial fibrillation (AF).

METHODS

The right atrial tissue samples were obtained from 64 patients with rheumatic heart diseases who underwent heart valve replacement surgery, and composed of 34 sinus rhythm (SR) patients and 30 AF patients. Hematoxylin and Eosin (HE) staining was used to observe cross-sectional area (CSA) of myocardial cell. Masson staining and measurement of connective tissue growth factor (CTGF), transforming growth factor beta 1 (TGF-β 1), and collagen type I/III (Collagen I/III) were performed to determine atrial fibrosis. The mRNA and protein levels of TRPM6 were detected by real-time quantitative polymerase chain reaction (RT-PCR) and western blotting, respectively.

RESULTS

Marked increases were observed in CSA of myocardial cell and myocardial collagen volume fraction in AF group compared with the SR group (all P<0.05). The mRNA levels of myocardial fibrosis markers (CTGF, TGF-beta 1, Collagen I/III) in AF group increased significantly compared to the SR group (all P<0.05). TRPM6 mRNA and protein levels in AF group were elevated markedly in comparison with SR group (P<0.01).

CONCLUSION

These findings revealed that increased TRPM6 mRNA and protein levels may contribute to atrial fibrosis, and suggested that TRPM6 might be involved in AF development by promoting fibrogenesis.

Clinical significance of markers of collagen metabolism in rheumatic mitral valve disease

BACKGROUND

Rheumatic Heart Disease (RHD), a chronic acquired heart disorder results from Acute Rheumatic Fever. It is a major public health concern in developing countries. In RHD, mostly the valves get affected. The present study investigated whether extracellular matrix remodelling in rheumatic valve leads to altered levels of collagen metabolism markers and if such markers can be clinically used to diagnose or monitor disease progression.

METHODOLOGY

This is a case control study comprising 118 subjects. It included 77 cases and 41 healthy controls. Cases were classified into two groups- Mitral Stenosis (MS) and Mitral Regurgitation (MR). Carboxy-terminal propeptide of type I procollagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP), total Matrix Metalloproteinase-1(MMP-1) and Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) were assessed. Histopathology studies were performed on excised mitral valve leaflets. A p value <0.05 was considered statistically significant.

RESULTS

Plasma PICP and PIIINP concentrations increased significantly (p<0.01) in MS and MR subjects compared to controls but decreased gradually over a one year period post mitral valve replacement (p<0.05). In MS, PICP level and MMP-1/TIMP-1 ratio strongly correlated with mitral valve area (r = -0.40; r = 0.49 respectively) and pulmonary artery systolic pressure (r = 0.49; r = -0.49 respectively); while in MR they correlated with left ventricular internal diastolic (r = 0.68; r = -0.48 respectively) and systolic diameters (r = 0.65; r = -0.55 respectively). Receiver operating characteristic curve analysis established PICP as a better marker (AUC = 0.95; 95% CI = 0.91-0.99; p<0.0001). A cut-off >459 ng/mL for PICP provided 91% sensitivity, 90% specificity and a likelihood ratio of 9 in diagnosing RHD. Histopathology analysis revealed inflammation, scarring, neovascularisation and extensive leaflet fibrosis in diseased mitral valve.

CONCLUSIONS

Levels of collagen metabolism markers correlated with echocardiographic parameters for RHD diagnosis.

Systemic and local levels of fetuin-a in calcified mitral valves of rheumatic heart disease

BACKGROUND AND AIM OF THE STUDY

Fetuin-A is a circulating glycoprotein that inhibits ectopic calcification. The study aim was first, to assess serum fetuin-A level in patients with calcified rheumatic mitral valve disease (RMVD), and second, to demonstrate the presence of fetuin-A by immunohistochemistry (IHC) in calcified RMVD which, to date, has not been verified in other studies.

METHODS

The study group comprised 68 adult patients with isolated RMVD and normal renal function. Of these patients, 34 (27 males, seven females; mean age 33.44 +/- 9.0 years) had severe calcification (Wilkins calcium score 3 or 4) and 34 (25 males, nine females; mean age 30.8 +/- 8.5 years) had mild calcification (Wilkins calcium score 1 or 2). A group of 32 age- and gender-matched healthy subjects (25 males, seven females; mean age 29.5 +/- 4.6 years) served as controls. Baseline serum fetuin-A levels were measured using an enzyme-linked immunosorbent assay (ELISA), while Wilkins calcium scores were assessed using either transthoracic or transesophageal echocardiography. Serum levels of calcium, phosphorus and alkaline phosphatase were assessed in all subjects. Histopathological examinations of ten severely calcific rheumatic mitral valves were made and compared with 10 non-calcified rheumatic mitral valves, all of which had undergone mitral valve replacement.

RESULTS

Serum fetuin-A levels were significantly lower in RMVD patients than in controls (108.83 +/- 7.1 versus 114.46 +/- 3.32 ng/ml; p = 0.014). However, there was no significant difference in fetuin-A level between patients with severe (C3/C4) versus mild calcification (C1/C2) (108.84 +/- 7.82 versus 108.82 +/- 6.36 ng/ml; p = NS). No correlation of fetuin-A was seen with serum high-sensitivity C-reactive protein, calcium, phosphorus and alkaline phosphatase, or with Wilkins' calcium score. IHC analyses revealed the presence of fetuin-A in the mesenchymal matrix and calcified area of calcific valves, while minimal to absent fetuin-A deposition was detected in the mesenchymal matrix of non-calcified mitral valves.

CONCLUSION

Serum fetuin-A levels were significantly decreased in patients with calcific RMVD. The present study was the first to demonstrate fetuin-A in the calcified mitral valve of rheumatic etiology, and suggests its possible role in the pathophysiology of calcific mitral valve disease. Further studies are required, however, to determine therapeutic implications.

Release of leukotriene B4, transforming growth factor-beta1 and microparticles in relation to aortic valve calcification

BACKGROUND AND AIM OF THE STUDY

Aortic stenosis, the most frequent valvulopathy in the Western world, is characterized by an important extracellular matrix (ECM) remodeling and a process of calcification in the aortic valves. One physiopathological assumption is that transforming growth factor-beta1 (TGF-beta1) acts through ECM remodeling and plays a role in calcification, implicating also microparticles (MPs). Another recent notion is the active involvement of inflammatory mediators in the calcification process of aortic stenosis.

METHODS

A total of 105 aortic valves was collected from patients suffering from calcified aortic stenosis with either tricuspid valve (AS) or bicuspid aortic valve (BAV), rheumatic aortic stenosis (RA), endocarditis, or aortic regurgitation (AR). Each valve was incubated for 24 h in culture medium and the supernatants (conditioned media) were used to measure the concentrations of leukotriene B4 (LTB4) and TGF-beta1 and to quantify the number of MPs released. Valvular calcification was evaluated using biphotonic absorptiometry.

RESULTS

LTB4 concentrations were significantly higher in media conditioned by AS valves compared to those conditioned by RA and endocarditis valves. In addition, LTB4 concentrations correlated significantly with the calcium content of the aortic valves. In contrast, the concentrations of TGF-beta1 and MPs in the conditioned media did not differ significantly between the various groups of valves, and there was no significant correlation between calcification and either TGF-beta1 or the number of MPs released from the aortic valves.

CONCLUSION

Taken together, these results indicate that inflammatory signaling through LTB4 may be more closely linked to calcification and aortic stenosis than signaling through TGF-beta1 and MPs.

Expression of NFkappaB, ICAM1, and VCAM1 in rheumatic heart disease with atrial fibrillation

OBJECTIVE

To examine the expression of nuclear factor kappaB (NFkappaB), intercellular adhesion molecule 1 (ICAM1), and vascular cell adhesion molecule 1 (VCAM1) levels in rheumatic heart disease patients who suffer from atrial fibrillation and those who do not.

STUDY DESIGN

Twenty-six patients with rheumatic heart disease were enrolled. Ten patients had no history of atrial fibrillation and 16 had atrial fibrillation. Atrial tissue was obtained from the right atrial appendage during heart surgery. The expression levels of NFkappaB, ICAM1, and VCAM1 were examined with immunohistochemical staining.

RESULTS

Myocardial inflammation and fibrosis were both increased in patients with atrial fibrillation. The levels of NFkappaB, ICAM1, and VCAM1 were significantly elevated in patients with atrial fibrillation as compared with the control group (all p < 0.05).

CONCLUSION

Overexpression of NFkappaB, ICAM1, and VCAM1 may be involved in the development and maintenance of atrial fibrillation in patients with rheumatic heart disease.

[Effect of hepatocyte growth factor and transforming growth factor-β(1) on atrial fibroblasts fibrosis]

OBJECTIVE

To investigate the effect of hepatocyte growth factor (HGF) and transforming growth factor-β(1) (TGFβ(1)) on the expression of α-smooth muscle actin (α-SMA) and collagen I in human atrial fibroblast in vitro, and to explore the possible molecular mechanism of atrial fibrosis in patients with atrial fibrillation (AF).

METHODS

Human atrial fibroblast, isolated from aseptic right atrial appendage tissues of 10 sinus rhythm (SR) and 10 chronic atrial fibrillation (CAF) patients, were cultured with HGF and TGFβ(1). mRNA expressions of collagen I and α-SMA were detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR), the protein expression of α-SMA was determined by immunofluorescence and Western blot.

RESULTS

(1) Compared with SR group, left atrium was significantly dilated in CAF group (t = 2.692, P < 0.05), the mRNA expression of collagen I and α-SMA of atrial fibroblasts were significantly upregulated (all P < 0.01), mRNA expression of collagen I was positively correlated with left atrial dimension (LAD) (r = 0.836, P = 0.014), AF duration (r = 0.739, P = 0.045) and α-SMA mRNA level (r = 0.886, P = 0.012). (2) Compared with SR group, the expression of α-SMA protein in CAF atrial fibroblasts were significantly increased (P < 0.01). (3) TGFβ(1) further stimulated while HGF significantly attenuated the expression of collagen I and α-SMA in CAF atrial fibroblasts (all P < 0.01).

CONCLUSIONS

Increasing expression of collagen I and α-SMA in human atrial fibroblasts might promote atria remodeling leading to the development and sustaining of AF. HGF is involved in the negative regulation on the expression of α-SMA and collagen I.

[The B lymphocytes D8/17 antigen expression and characteristics of patients with rheumatic heart disease in Guangdong]

OBJECTIVE

To investigate the D8/17 antigen expression of patients with rheumatic heart disease (RHD) in Guangdong province and study the antigen's characteristics.

METHODS

The level of D8/17 antigen expression on B lymphocytes was determined with flow cytometry assay in 96 RHD patients and 83 unaffected controls. The percentage of B-cells expressing the D8/17 antigen having more than 10% was considered to be positive. D8/17 antigen was extracted by immunoprecipitation, and the antigen characteristics was analyzed by tandem mass spectrometry.

RESULTS

The mean percentage of B-cells expressing the D8/17 antigen was (85.36 ± 15.15)% in the RHD patients and (82.89 ± 4.55)% in the controls, with no significant difference between the two groups (P = 0.436). Moreover, the positive rate of the D8/17 expression was 100% in either the RHD patients or the controls. The molecular weight of D8/17 antigen was found to be 40 000 - 67 000, and the purified protein was most likely to match moesin or β-actin.

CONCLUSIONS

B-cell antigen D8/17 is not associated with RHD in Guangdong province of China. Moesin or β-actin is the most likely protein to match D8/17 antigen.

Does the expression of transforming growth factor β-1: affect the outcome of the radiofrequency modified maze procedure in patients with rheumatic atrial fibrillation?

We investigated whether the expression of transforming growth factor β-1 in the left atrial appendage affected the outcome of the radiofrequency modified maze procedure in patients with rheumatic valve disease and long-standing persistent atrial fibrillation.Messenger RNA and protein expression of transforming growth factor β-1 and volume fractions of collagen types I and III were measured in 80 patients with rheumatic valve atrial fibrillation who underwent valve surgery with the radiofrequency modified maze procedure; the same was done in a control group of 20 patients with rheumatic valve disease and sinus rhythm who underwent valve surgery alone.At 6 months' follow-up, atrial fibrillation recurred in 24 of the 80 patients in the study group. The messenger RNA and protein expressions of transforming growth factor β-1, collagen type I volume fraction, and left atrial dimension had increased gradually in the control group and in the study subgroups that maintained sinus rhythm or relapsed into atrial fibrillation (P <0.05). The messenger RNA and protein expressions of transforming growth factor β-1 correlated positively with collagen type I volume fraction (r=0.723, P <0.001 and r=0.745, P <0.001, respectively) and left atrial dimension (r=0.762, P <0.001 and r=0.765, P <0.001, respectively). In the sinus rhythm-maintained subgroup, the patients who regained functional atrial contraction had lower messenger RNA and protein expression of transforming growth factor β-1 than did the patients who failed to retain such function (P <0.05).We conclude that the expression of transforming growth factor β-1 in the resected left atrial appendage affects the recurrence of atrial fibrillation and restoration of functional left atrial contraction after the radiofrequency modified maze procedure.

[Changes in oxidative stress and apoptosis parameters of neutrophils in rheumatoid diseases]

AIM

Study parameters of oxidative stress and apoptosis of neutrophils in patients with ankylosing spondylitis, systemic lupus erythematosus, systemic scleroderma and rheumatoid heart disease.

MATERIALS AND METHODS

240 patients with rheumatoid diseases and 25 healthy control group volunteers were examined. Neutrophil isolation from peripheral blood was performed by using double density gradient of ficoll-urografin. Cell functional activity was studied by chemiluminescence method. Pro-apoptosis antigen bak expression by neutrophils was studied by using streptavidin-biotin method. Griss reagent was used for nitrogen oxide production analysis.

RESULTS

An increase of oxygen dependent neutrophil metabolism processes was detected in patients with ankylosing spondylitis in comparison with systemic lupus erythematosus and systemic scleroderma patients. Systemic lupus erythematosus is characterized by higher biocidity of neutrophils in comparison with systemic scleroderma and rheumatoid heart disease. Increase of neutrophil granulocyte activity in ankylosing spondylitis is accompanied by an increase of superoxide-anion formation. In spite of high level of metabolic activity neutrophils in patients with ankylosing spondylitis have a low functional reserve, and neutrophils in patients with systemic scleroderma have the highest reserve potential.

CONCLUSION

Differences in expression parameters of oxidative stress by neutrophils depend on nosological form, varying by production level and active oxygen form formation reserve.

[Relationship between early spontaneous cardioversion of atrial fibrillation and thyroid hormone metabolism after mitral replacement in patients with rheumatic heart disease]

OBJECTIVE

To analyze the relationship between early spontaneous cardioversion of atrial fibrillation (AF) and thyroid hormone metabolism after mitral replacement in patients with rheumatic heart disease, and explore the treatment strategy of early spontaneous cardioversion after mitral valve replacement.

METHODS

According to the occurrence of cardioversion, 138 patients with mitral valve replacement were divided into conversion group and non-conversion group, and based on the duration of sinus rhythm, the patients in conversion group were divided into < 3 days group and > 3 days group. Triiodothyronine (T3) was detected by radioimmunoassay in all the patients.

RESULTS

T3 metabolism decreased significantly after the operation in all the patients. Early spontaneous cardioversion of AF occurred 2 h after the operation in 52 cases (37.7%), and 28 (20.3%) of the cases had a duration of sinus rhythm longer than 3 days. T3 was significantly decreased in conversion group and non-conversion group by 44.5% and 58.7% at 2 h, by 40.0% and 52.4% at 24 h and by 28.6% and 37.7% at 72 h after the operation, respectively. The levels of T3 in conversion group was significantly higher than the levels in non-conversion group, and showed no significant variation with the duration of sinus rhythm.

CONCLUSION

Enhancement of T3 levels after mitral valve replacement may increase the probability of early spontaneous cardioversion of AF, but can not affect the duration of sinus rhythm. This finding supports the supplementation of T3 perioperatively in patients undergoing cardiac surgeries.

Association of serum fetuin-A with valvular calcium concentration in rheumatic mitral valve disease

BACKGROUND AND AIM OF THE STUDY

Fetuin-A is an acute-phase glycoprotein that inhibits ectopic calcification. The study aim was to assess serum fetuin-A levels in patients with rheumatic mitral valve disease (RMVD), and to evaluate the association of fetuin-A with the extent of mitral valve calcification, determined either echocardiographically or by the measurement of calcium and phosphorus concentrations in the resected valve tissues.

METHODS

The study group comprised 21 patients (14 females, seven males; mean age 48 +/- 12.4 years) with RMVD, who were scheduled for mitral valve replacement surgery, while 30 age- and gender-matched healthy subjects (17 females, 13 males; mean age 43.6 +/- 11.1 years) served as a control group. Baseline serum fetuin-A levels were measured using ELISA, and high-sensitivity C-reactive protein (hs-CRP) levels using immunonepholometry. A Wilkins score was calculated using transesophageal echocardiography, and the resected valve tissues were analyzed for concentrations of calcium and phosphorus.

RESULTS

Serum fetuin-A levels were lower and hs-CRP levels higher in the study group than in controls (300.4 +/- 92.5 microg/ml versus 352.6 +/- 55.3 microg/ml, p = 0.028; and 1.9 +/- 1.2 mg/dl versus 0.3 +/- 0.2 mg/dl, p < 0.0001, respectively). An inverse correlation was found between serum fetuin-A and hs-CRP levels (r = -0.690, p = 0.001). A significant association of either serum fetuin-A or hs-CRP was also found to occur with calcium concentration in the mitral valve tissue (r = -0.684, p = 0.001, and r = 0.510, p = 0.018, respectively), but not with the Wilkins calcium score. Serum fetuin-A and phosphorus concentrations in the MV tissue were independent predictors of calcium concentration in the MV tissue.

CONCLUSION

Serum fetuin-A, which is significantly decreased in patients with RMVD, is an independent predictor of calcium concentration in the mitral valve tissue.

Angiotensin II receptor type 1 is upregulated in atrial tissue of patients with rheumatic valvular disease with atrial fibrillation

OBJECTIVE

The purpose of this study was to examine the changes in expression of angiotensin II receptor type 1/2 in left or right atrial tissue from patients with rheumatic valvular disease with or without atrial fibrillation.

METHODS

Atrial tissue samples were obtained from 39 patients with rheumatic mitral valve disease during cardiac surgery. Among these patients, there were 25 with atrial fibrillation and 14 with sinus rhythm. The level of angiotensin II receptor type 1 or type 2 mRNA transcription was measured by means of a semiquantitative reverse transcription-polymerase chain reaction technique. Expression of angiotensin II receptor type 1 or type 2 protein was detected by means of immunohistochemistry assay and Western blot analysis.

RESULTS

The inner diameter of the left atrium was clearly enlarged in the atrial fibrillation group in comparison with that seen in the sinus rhythm group. The expression levels of both angiotensin II receptor type 1 mRNA and protein in the left atrial tissue were significantly increased in the patients with atrial fibrillation compared with those seen in patients with sinus rhythm (P < .05). Interestingly, the comparison of angiotensin II receptor type 2 expression levels in the left atrial tissue between these 2 groups is not statistically significant. In addition, the results of angiotensin II receptor type 1 or 2 expression in the right atrial tissue did not show any obvious change in the patients with atrial fibrillation versus those with sinus rhythm.

CONCLUSIONS

Expression of angiotensin II receptor type 1 but not type 2 is highly upregulated only in the left atrial tissue of patients with rheumatic valvular disease with atrial fibrillation. This suggests that there is a possible pathophysiologic role of the renin-angiotensin system in patients with atrial fibrillation and that a series of effects mediated by the activation of angiotensin II receptor type 1 in the left atrial tissue might be one of the molecular mechanisms involved in the process of atrial remodeling in atrial fibrillation.

[Expression and significance of matrix metalloproteinase-1,9, tissue inhibitor of metalloproteinase-4 and extracellular matrix metalloproteinase inducer in the myocardium of congestive heart failure in patients with rheumatic heart diseases]

OBJECTIVE

To investigate the expression of the matrix metalloproteinase-1, -9 (MMP-1,9), and tissue inhibitor of metalloproteinase-4 (TIMP-4), extracellular matrix metalloproteinase inducer (EMMPRIN) in the myocardium of congestive heart failure in patients with rheumatic heart diseases.

METHODS

The papillary muscle specimens of the left ventricle were obtained from 18 patients with heart failure during rheumatic heart valve replacement, and the normal specimens were obtained from the autopsy of 10 adults without heart disease. The specimens were stained to examine the expression of MMP-1, MMP-9, TIMP-4, and EMMPRIN by the EnVision immunohistochemical assays.

RESULTS

The expressions of MMP-1, MMP-9, and EMMPRIN in the myocardium of the patients with the cardiac function classes III and IV (NYHA III and IV) were significantly higher than those the normal cardiac function (NYHA I) (P<0.05) except MMP-1 expression between NYHA III and I. The TIMP-4 level was significantly lower in patients with NYHA III and IV than that of the NYHA I ( P<0.05). The expression of MMP-1, MMP-9, and EMMPRIN was significantly higher in patients with atrial fibrillation than those in the control group with regular sinus rhythm (P<0.05), whereas the TIMP-4 level was obviously lower in patients with atrial fibrillation than that in the control group with regular sinus rhythm (P<0.05). The expressions of MMP-1, MMP-9, and EMMPRIN were positively correlated with each other, but were negatively correlated with TIMP-4.

CONCLUSION

MMPs, TIMP, and EMMPRIN were significantly unbalanced in the myocardium of congestive heart failure patients with rheumatic heart diseases. They may play an important role in congestive heart failure through myocardial remodeling.

[Expression of angiotensin II receptor subtypes in atrial fibrillation underlying rheumatic heart disease]

OBJECTIVE

To examine the expression of angiotensin II (Ang II) receptor subtypes in human left and right atrial tissue in atrial fibrillation underlying rheumatic heart disease.

METHODS

Atrial tissue samples were obtained from 39 patients with rheumatic heart disease, 25 with atrial fibrillation (AF) and 14 with sinus rhythm(SR) during open heart surgery. AT1 and AT2 mRNA levels were measured with semi-quantitative reverse transcription polymerase chain reaction techniques. AT1 and AT2 protein levels were measured with immunohistochemical techniques.

RESULTS

Compared with that of the SR group, left atrial inner diameter was significantly increased in the patients of the AF group. The AT1 mRNA and protein levels in the LA significantly increased in patients with AF compared with those in patients with SR (P < 0.05), whereas AT2 mRNA and protein were not significantly altered. Investigations of Ang II receptor subtypes' mRNA and protein levels in the RA did not exhibit any significant changes either in AT1 or AT2 in patients with AF and SR.

CONCLUSIONS

AF is associated with an up-regulation of AT1 in LA, but does not appear to influence the AT2 expression. This may indicate a possible pathophysiologic role for renin-angiotensin system in the development of AF. The series of effects mediated by AT1 activation may be one of the molecular mechanisms involved in the process of atrial remodeling.

Synergistic effects of cyclic strain and Th1-like cytokines on tenascin-C production by rheumatic aortic valve interstitial cells

Tenascin-C (TN-C) is a key component of extracellular matrix (ECM) and its expression process is poorly understood during rheumatic heart valvular disease (RHVD). In this study, we found that interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and TN-C concentrations in patients with RHVD were significantly higher than in normal controls. More IFN-gamma receptors and TNF receptors were found being expressed on rheumatic aortic valves interstitial cells than on non-rheumatic ones and their expression was patients' sera dependent. Antibodies neutralizing IFN-gamma or TNF-alpha could attenuate patients' sera-induced TN-C transcription by isolated rheumatic aortic valves interstitial cells. By application with different protein kinase inhibitors, we found that combined with cyclic strain, TNF-alpha and IFN-gamma induced TN-C transcription through the RhoA/ROCK signalling pathway. At the same time, p38 mitogen-activated protein kinase was involved in TNF-alpha and IFN-gamma induced TN-C transcription. TNF-alpha also increased TN-C mRNA level by additional PKC and ERK 1/2 activation. Our finding revealed a new insight into ECM remodelling during RHVD pathogenesis and new mechanisms involved in the clinical anti-IFN-gamma and anti-TNF-alpha therapy.

Plasma and tissue oxidative stress index in patients with rheumatic and degenerative heart valve disease

OBJECTIVES

We investigated whether patients with rheumatic and degenerative heart valve disease (HVD) differed with regard to plasma and tissue oxidative stress index (OSI).

STUDY DESIGN

The study included 56 patients who underwent valve replacement due to rheumatic (n=32; 15 males; mean age 47+/-10 years) and degenerative (n=24; 13 males; mean age 55+/-12 years) HVD. Plasma and tissue total oxidative status (TOS) and total antioxidative capacity (TAC) levels were measured and OSI was calculated.

RESULTS

Patients with degenerative HVD had significantly higher age, increased interventricular septum thickness, and higher frequency of aortic stenosis, whereas the incidence of mitral stenosis was higher in patients with rheumatic HVD (p<0.05). Plasma oxidative characteristics did not differ between the two HVD groups (p>0.05). Tissue TAC was significantly lower in patients with rheumatic HVD (p=0.027), whereas tissue TOS and OSI were similar between the two HVD groups (p>0.05). In bivariate analysis, plasma OSI did not show any correlation with clinical, laboratory, and echocardiographic variables (p>0.05).

CONCLUSION

Our data show that plasma and tissue OSI levels are similar in patients with rheumatic and degenerative HVD.

[Atrial 11beta-hydroxysteroid dehydrogenase type 2 expression in rheumatic heart disease patients with or without atrial fibrillation]

OBJECTIVE

To investigate the mRNA and protein expressions of 11beta-Hydroxysteroid dehydrogenase type 2 (11betaHSD2) in patients with atrial fibrillation.

METHODS

Right and left atrial lateral wall tissue samples were obtained during mitral/aortic valve replacement operation from 25 patients with rheumatic heart valve disease (12 in sinus rhythm and 13 in chronic atrial fibrillation). Realtime quantitative PCR and Western blot were used to determine the mRNA and protein expressions of 11betaHSD2 in atria specimens. The distribution of 11betaHSD2 in human atrial tissue was analyzed by specific immunohistochemical staining. Echocardiography examination was performed before operation.

RESULTS

The left atrial diameters were significantly higher in the atrial fibrillation group as compared to sinus rhythm group (P < 0.01). Similarly, mRNA expression of 11betaHSD2 (0.86 +/- 0.14 vs 0.33 +/- 0.12 in right atria, 0.95 +/- 0.15 vs 0.37 +/- 0.10 in left atria, all P < 0.01) and protein expression of 11betaHSD2 (1.18 +/- 0.64 vs 0.71 +/- 0.21 in right atria, P < 0.01; and 1.36 +/- 0.58 vs 0.85 +/- 0.15 in left atria, P < 0.05) were also significantly upregulated in atrial fibrillation groups than those in sinus rhythm groups. The mRNA and protein expressions of 11betaHSD2 were similar between left atria and right atria both in fibrillation and sinus groups (all P > 0.05). The special immunohistochemical staining demonstrated that 11betaHSD2 was abundant in the human atrial myocardium and located mainly in the cytoplasm.

CONCLUSION

These findings suggested that upregulated 11betaHSD2 might be associated to the development and persistence of atrial fibrillation.

Overexpression of transforming growth factor-beta 1 in the valvular fibrosis of chronic rheumatic heart disease

For the purpose of determining the pathogenic role of transforming growth factor-beta1 (TGF-beta 1) in the mechanism of chronic rheumatic heart disease, we evaluated the expression of TGF-beta 1, proliferation of myofibroblasts, and changes in extracellular matrix components including collagen and proteoglycan in 30 rheumatic mitral valves and in 15 control valves. High TGF-beta 1 expression was identified in 21 cases (70%) of rheumatic mitral valves, whereas only 3 cases (20%) of the control group showed high TGF-beta 1 expression (p<0.001). Additionally, increased proliferation of myofibroblasts was observed in the rheumatic valves. High TGF-beta1 expression positively correlated with the proliferation of myofibroblasts (p=0.004), valvular fibrosis (p<0.001), inflammatory cell infiltration (p=0.004), neovascularization (p=0.007), and calcification (p<0.001) in the valvular leaflets. The ratio of proteoglycan to collagen deposition inversely correlated with TGF-beta 1 expression in mitral valves (p=0.040). In conclusion, an ongoing inflammatory process, the expression of TGF-beta 1, and proliferation of myofibroblasts within the valves have a potential role in the valvular fibrosis, calcification, and changes in the extracellular matrix that lead to the scarring sequelae of rheumatic heart disease.

Rheumatic fever and rheumatic heart disease: genetics and pathogenesis

Molecular mimicry between streptococcal and human proteins is considered as the triggering factor leading to autoimmunity in rheumatic fever (RF) and rheumatic heart disease (RHD). Here, we present a review of the genetic susceptibility markers involved in the development of RF/RHD and the major immunopathological events underlying the pathogenesis of RF and RHD. Several human leucocyte antigen (HLA) class II alleles are associated with the disease. Among these alleles, HLA-DR7 is predominantly observed in different ethnicities and is associated with the development of valvular lesions in RHD patients. Cardiac myosin is one of the major autoantigens involved in rheumatic heart lesions and several peptides from the LMM (light meromyosin) region were recognized by peripheral and intralesional T-cell clones from RF and RHD patients. The production of TNF-alpha and IFN-gamma from heart-infiltrating mononuclear cells suggests that Th-1 type cytokines are the mediators of RHD heart lesions while the presence of few interleukin-4 producing cells in the valve tissue contributes to the maintenance and progression of the valvular lesions.

[Collagen type I and interleukin-1 beta gene expression in human atria during atrial fibrillation]

OBJECTIVE

To determine whether gene expression of collagen type I and interleukin-1 beta (IL-1beta) is altered in patients with atrial fibrillation (AF).

METHODS

Right atrial tissue samples were taken from 75 patients with rheumatic heart disease who underwent heart valve replacement surgery. 34 patients had no history of AF, 11 patients had paroxysmal AF and 30 patients had persistent AF. The mRNA content of collagen type I and IL-1beta was measured with semi-quantitative RT-PCR.

RESULTS

The mRNA content of collagen type I was significantly increased in the persistent AF group (P < 0.001) and increased in the paroxysmal AF group (P < 0.05) as compared with that in the sinus rhythm group. The mRNA content of IL-1beta was up-regulated in the persistent AF group (P < 0.05), but the trend of increase did not reach statistical significance in the paroxysmal AF group (P > 0.05). The mRNA content of IL-1beta was significantly correlated with the mRNA content of collagen type I (r = 0.295, P = 0.011), left atrial dimension (r = 0.385, P = 0.001) and AF duration (r = 0.326, P = 0.004).

CONCLUSION

The upregulation of IL-1beta gene expression in atrium may contribute to the atrial fibrosis during AF through influencing collagen metabolism.

Correlation of tissue selectin expression and hemodynamic parameters in rheumatic mitral valve disease

BACKGROUND AND AIM OF THE STUDY

The study aim was to examine tissue expression of the adhesion molecules E-selectin and P-selectin on atrial, valvular and atrial myocardial blood vessel endothelium in patients with rheumatic mitral stenosis, and to investigate whether such expression was correlated with hemodynamics.

METHODS

Thirteen patients (eight women, five men; mean age 51 +/- 10 years) with severe rheumatic mitral stenosis who underwent mitral valve replacement surgery were examined on preoperative day 1, using cardiac catheterization and echocardiography. Specimens from the mitral valve and left atrium of each patient were evaluated for CD 62E and CD 62P expression using indirect immunoperoxidase and immunofluorescence techniques

RESULTS

A great majority of patients presented E and/or P selectin expression of variable intensity on atrial, valvular and atrial myocardial blood vessel endothelium. A more diffuse and stronger reaction for CD 62P was noted compared to that for CD 62E. The left ventricular end-diastolic diameter and left atrial diameter were positively correlated with endocardial CD 62P and CD 62E expression. Right atrial pressure was also strongly and positively correlated with endocardial expression of CD 62E (r = 0.80, p 0.03) and CD 62P (r = 0.8, p = 0.02).

CONCLUSION

Marked tissue expression of CD 62E and CD 62P was identified on atrial, valvular and atrial myocardial blood vessel endothelium. Moreover, the degree of expression of adhesion molecules was significantly correlated with the left atrial and left ventricular chamber diameters, as well as right atrial pressure.

Oxidative stress and antioxidant status in cardiovascular diseases in population of western Nepal

OBJECTIVES

To observe if there is any connectivity between oxidative stress and cardiovascular diseases (CVDs).

MATERIALS AND METHODS

Patients suffering from different cardiovascular diseases (hypertension, ischemic heart disease, rheumatic heart disease) attending Manipal Teaching Hospital, Pokhara and strictly matched controls were selected for this study. Oxidative stress (OS) was measured by plasma thiobarbituric acid reacting substances (TBARS) where as antioxidant status was measured by estimating vitamin E, vitamin C and total antioxidant activity (TAA) in plasma.

RESULTS

The mean level of TBARS, TAA, vitamin C and E were 2.20+0.43 nmol/ml, 547+98 mol/l, 0.88+0.15 mg/dl and 0.75+0.20 mg/dl respectively in patients. The respective values in controls were 1.86+0.43 nmol/ml, 859+139 mol/l, 0.94+0.15 mg/dl and 1.10+0.30 mg/dl. Although the OS seems to be raised in patients, is practically insufficient to oxidize biomolecules and induce CVDs. Despite vitamin C and E levels being well within normal limits, the TAA was significantly and considerably lower in patients. This is a highly interesting observation suggesting that dietary antioxidants other than these vitamins were preferentially consumed to control OS because procedure for TAA used in this study practically measures only total dietary antioxidants.

CONCLUSION

OS does not appear to be an etiological factor for the cardiovascular diseases; rather slightly raised OS in patients seems to be a consequence. Further the raised OS was not due to lower nutrient antioxidant (vit. C and vit. E) in the local population studied herein.

Mimicry in recognition of cardiac myosin peptides by heart-intralesional T cell clones from rheumatic heart disease

Molecular mimicry between Streptococcus pyogenes Ags and human proteins has been considered as a mechanism leading to autoimmune reactions in rheumatic fever and rheumatic heart disease (RHD). Cardiac myosin has been shown as a putative autoantigen recognized by autoantibodies of rheumatic fever patients. We assessed the human heart-intralesional T cell response against human light meromyosin (LMM) and streptococcal M5 peptides and mitral-valve-derived proteins by proliferation assay. Cytokines induced by LMM peptides were also evaluated. The frequency of intralesional T cell clones that recognized LMM peptides was 63.2%. Thirty-four percent of T cell clones presented cross-reactivity with different patterns: 1) myosin and valve-derived proteins; 2) myosin and streptococcal M5 peptides; and 3) myosin, valve-derived proteins and M5 peptides. In addition, several LMM peptides were recognized simultaneously showing a multiple reactivity pattern of heart-infiltrating T cells. Inflammatory cytokines (IFN-gamma and TNF-alpha) were predominantly produced by heart-infiltrating T cells upon stimulation with LMM peptides. The alignment of LMM and streptococcal M5 peptides showed frequent homology among conserved amino acid substitutions. This is the first study showing the cellular response by human heart-infiltrating T cells against cardiac myosin epitopes in RHD patients. The high percentage of reactivity against cardiac myosin strengthens its role as one of the major autoantigens involved in rheumatic heart lesions. T cell reactivity toward myosin epitopes in RHD patients may also trigger the broad recognition of valvular proteins with structural or functional similarities.

[Calpain-I, calpastatin, caspase-3 and apoptosis in the human left atrium in rheumatic atrial fibrillation]

OBJECTIVE

The aim of the present study was to detect the expression of calpain-I, calpastatin, caspase-3 and apoptosis in the left atria of patients with rheumatic heart disease (RHD), and to find the association of these factors. Also, it was intended to investigate the effect of the above factors on the mechanism of atrial fibrillation (AF).

METHODS

43 patients with RHD undergoing valve-replacement were included, 15 patients with regular sinus rhythm (Group RSR), 8 patients with paroxysmal AF (Group AF1) and 20 patients with permanent AF (Group AF2). Western blot was used to examine the content of calpain-I, caspase-3 and calpastatin. The apoptosis index (AI) was measured by TUNEL.

RESULTS

(1) Expression of calpain-I in group AF2 was increased to (344.0 +/- 101.9)%, and caspase-3 was increased to (394.0 +/- 99.4)% compared to group RSR (P < 0.01, respectively). Amount of calpastatin was reduced to (27.0 +/- 12.8)% (P < 0.01). The expressions of these proteins were unchanged in group AF1. (2) AI in group AF2 was higher than that in groups RSR and AF1 (P < 0.01). (3) In group AF2, the levels of calpain-I, caspase-3 and AI were positively relative to left atrial dimension and AF duration, P < 0.05 - 0.01, respectively, whereas calpastatin was negatively correlated with left atrial dimension and AF duration (P = 0.007 and P = 0.001, respectively). (4) The protein content of calpain-I was positively related with that of caspase-3 and AI (P < 0.01, respectively), and the content of calpastatin was negatively related with that of calpain-I and caspase-3 (P < 0.01, respectively).

CONCLUSIONS

Apoptosis of atrial cell increased in left atria and the protein contents of calpain-I, caspase-3 and calpastatin significantly altered during AF in humans with RHD. The observed interactions suggest that these factors compose a system to cause the structural remodeling and dysfunction of atria. The course may play a key role in promoting the onset and maintenance of AF.

Molecular pathogenesis of rheumatic fever and rheumatic heart disease

Molecular mimicry between streptococcal and human proteins has been proposed as the triggering factor leading to autoimmunity in rheumatic fever (RF) and rheumatic heart disease (RHD). This article summarises studies on genetic susceptibility markers involved in the development of RF/RHD. It also focuses on the molecular mimicry in RHD mediated by the responses of B and T cells of peripheral blood, and T cells infiltrating heart lesions, against streptococcal antigens and human tissue proteins. The molecular basis of T-cell recognition is assessed through the definition of heart-crossreactive antigens. The production of cytokines from peripheral and heart-infiltrating mononuclear cells suggests that T helper 1 (Th1)-type cytokines are the mediators of RHD heart lesions. An insufficiency of interleukin 4 (IL-4)-producing cells in the valvular tissue might contribute to the maintenance and progression of valve lesions.

Rheumatoid disease and ischaemic heart disease: Insights from pathophysiology and vascular biology

Rheumatoid disease (RD) is a multisystem inflammatory disorder, which is associated with an increased cardiovascular mortality, thought to be due to ischaemic heart disease (IHD). The precise mechanisms causing increased IHD in RD are unclear. However, there is increasing recognition that atherosclerosis is another chronic inflammatory condition, which shares several pathophysiological features with RD. For example, endothelial damage/dysfunction, platelet activation, hypercoagulability and angiogenesis are well-recognised in both disease processes. Furthermore, RD may influence traditional risk factors such as dyslipidaemia. Although the exact reasons for the increased ischaemic burden are unclear, physicians should place a high priority upon reducing cardiovascular risk in sufferers of RD. This review summarises factors that might contribute to the pathogenesis of IHD in RD. Discussion will focus upon features shared by atherosclerotic and rheumatoid processes, as well as possible interactions between RD and conventional IHD risk factors.

[Changes of interleukin-1beta and tumor necrosis factor-alpha of right atrial appendages in patients with rheumatic valvular disease complicated with chronic atrial fibrillation]

OBJECTIVE

To investigate whether atrial expression of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) of right atrial appendages are altered in patients with rheumatic valvular disease during chronic atrial fibrillation.

METHODS

A total of 48 patients with rheumatic heart disease were included. 27 patients had no history of atrial fibrillation, 21 patients had atrial fibrillation. Atrial tissue was obtained from the right atrial appendage during open heart surgery. The protein expression of IL-1beta and TNF-alpha was detected by immunohistochemistry method. The fibrosis of right atrial appendage was detected by Masson staining.

RESULTS

The fibrosis of right atrial appendage was significantly increased in patients with chronic atrial fibrillation. The protein expression of IL-1beta and TNF-alpha were significantly increased in patients with chronic atrial fibrillation.

CONCLUSIONS

The protein expression of IL-1beta and TNF-alpha were significantly increased in patients with rheumatic valvular disease during chronic atrial fibrillation. Inflammation may be one of the mechanisms for the development and persistence of atrial fibrillation.

[Activity of lipid peroxidation processes in children with rheumatic fever]

Pathogenic mechanism of acute and chronic inflammation is connected to the increased production of superoxide anion, hydrogen peroxide, and other free radicals. Clinical role of lipid peroxidation (LPO) processes was studied in 38 patients in the age from 3 to 15 years old with different variants of Rheumatic Fever (RF). We have investigated the relationship between malonidialdehide (MDA) and RF. We measured the levels of MDA in the plasma in patients with acute rheumatic fever (ARF) and chronic rheumatic heart disease (CRHD). Our study revealed that the levels of MDA in patients with ARF are significantly higher than in patients with CRHD. These levels were also significantly higher in patients with history of disease for up to 2 years, than in patients with history longer than 2 years. Thus, the measurement of MDA in the plasma could be used as a laboratory test for relation of active state of rheumatic fever.

Effect of fibroblast growth factor-2 on pannus formation in replacement prosthetic heart valves

BACKGROUND AND AIM OF THE STUDY

Fibroblast growth factor-2 (FGF-2) is a multifunctional protein which plays a role in smooth muscle cell growth, wound healing, tissue repair and angiogenesis. FGF-2 is also released by mechanically wounded cells. Herein, the importance of FGF-2 release from periannular tissue in the mechanism of pannus formation in obstructed mechanical prostheses was investigated.

METHODS

Between January 1993 and December 2002, 35 patients with an obstructed bileaflet prosthetic mitral valve were classified according to the nature of obstruction as either thrombus or pannus. Data were related to patient age and gender, prosthesis model and size, intraoperative and pathology findings, and interval between implant and thrombosis. FGF-2 release was monitored immunohistochemically in all cases.

RESULTS

Thrombus formation was found in 19 patients, and pannus formation in 16. Patients were reoperated on after 3.10 +/- 0.7 years in the thrombus group, and after 6.3 +/- 0.46 years in the pannus group (p = 0.04). A foreign body reaction was found 78.9% of thrombus patients and 81.2% of pannus patients (p = 0.602), chronic inflammation in 31.5% and 50%, respectively (p = 0.317), and FGF-2 release in 78.9% and 87.5%, respectively (p = 0.582).

CONCLUSION

As FGF-2 release was similar in both patient groups, the duration of FGF-2 release from injured periannnular tissue was considered to form part of the chronic healing process, and was not attributed to mitral valve obstruction by pannus formation.

[Effects of ulinastatin on erythrocyte lipid peroxidation in patients undergoing open heart surgery]

OBJECTIVE

To investigate the effects of ulinastatin on erythrocyte lipid peroxidation in patients undergoing open heart surgery.

METHODS

Twenty adult patients with rheumatic heart disease undergoing elective value replacement were divided randomly into 2 groups of 10 patients each: a control group (group C) and an ulinastatin group (group W). The patients were premedicated with intramuscular morphine 0.08 mg/kg and scopolamine 0.06 mg/kg. Anesthesia was induced with midazolam 0.1 mg/kg, fentanyl 5 microg/kg and vecuronium 0.1 mg/kg. After the tracheal intubation, the patients were mechanically ventilated. Anesthesia was maintained with midazolam, fentanyl and isoflurane. Blood samples were taken from radial artery before the operation (T1), 30 min after the initiation of CPB (T2), at the end of the CPB (T3), 30 min after the aorta declamping (T4) and 24 h after the operation (T5) for the determination of plasma and erythrocyte MDA (P-MDA and E-MDA) and erythrocyte SOD (E-SOD).

RESULTS

The levels of P-MDA and E-MDA increased significantly after the initiation of CPB and the level of E-SOD was higher than the baseline level at T2, and then decreased from T3 to T5 in group C (P <0.001). The levels of P-MDA and E-MDA didn't increased until T4 (P <0.001) and returned to the baseline level at T5 in group W. The levels of P-MDA and E-MDA were significantly higher in group C than those in group W and the level of E-SOD was markedly lower than that in group W (P <0.05).

CONCLUSION

Ulinastatin can alleviate erythrocyte lipid peroxidation in patients undergoing open heart surgery.

[The relationship between gap junctional remodeling and atrial fibrillation in patients with rheumatic heart disease]

OBJECTIVE

To investigate the relationship between the alternations in the expression and distribution of connexin 40 (Cx40) and connexin 43 (Cx43) and atrial fibrillation (AF) in patients with rheumatic heart disease.

METHODS

Biopsy was conducted to take specimens of right atrial appendage (RAA) from 32 patients with rheumatic heart disease, 21 with AF and 11 with sinus rhythm (SR) during valve replacement. The protein levels of Cx40 and Cx43 were examined by immunoconfocal microscopy and Western blotting. The former was also used to observe the distribution of Cx40 and Cx43 double-labeled with antibodies against Cx40 and Cx43.

RESULTS

Immunoconfocal microscopy showed that the relative expression level of Cx40 protein in the specimens of RAA in the chronic AF group was (0.67 microm(2)/ microm(3) +/- 0.09 microm(2)/ microm(3)), significantly lower than that in the SR group (1.45 microm(2)/ microm(3) +/- 0.16 microm(2)/ microm(3)) (P < 0.01). There was no significant difference in the expression of Cx43 protein between the two groups. Distributed inhomogeneously, Cx40 and Cx43 were mainly located at the side to side interconnections, instead of being confined to the intercalated discs, as observed in the patients with SR. The results of Western blotting were similar to those of immunoconfocal microscopy.

CONCLUSION

The reduction and redistribution of Cx40 and Cx43 contribute to initiation and persistence of AF in patients with rheumatic heart disease.

Selective depletion of Vbeta2+CD8+ T cells in peripheral blood from rheumatic heart disease patients

Acute rheumatic fever (ARF) and its chronic valvular sequelae are the delayed consequence of a pharyngeal infection with group A Streptococcus (GAS). Several GAS proteins have been shown to be superantigens, raising the possibility that the expansion or deletion of T cells expressing specific Vbeta regions might play a role in the pathogenesis of ARF or chronic rheumatic heart disease (RHD). We therefore analyzed by four-color flow cytometry, the Vbeta repertoire on CD3, CD4 and CD8 T cells from four ARF patients, 10 RHD patients and also nine healthy controls. A selective depletion of Vbeta2+ T cells was found only in the CD8 subset of chronic RHD patients. This is of interest since a number of GAS superantigens exert their effects on Vbeta2+ cells and because only CD8+ T cells from ARF and RHD patients undergo anergy in response to GAS superantigens. Our results suggests that an ongoing immune process is present in RHD patients and that CD8+ T cells may have an important immunoregulatory role in the pathogenesis of the disease.

Increased levels of high sensitive C-reactive protein in patients with chronic rheumatic valve disease: evidence of ongoing inflammation

The precise pathogenetic mechanism(s) of rheumatic fever and rheumatic heart disease have never been defined. C-reactive protein (CRP) is increased in patients with acute rheumatic fever, but it is not known whether plasma levels increase in patients with chronic rheumatic valve disease. The aim of this study was to determine the role of inflammation detected by high sensitivity CRP (hs-CRP) levels in the progression of chronic rheumatic valve disease. A total of 113 patients with chronic rheumatic valve disease (81 women, 32 men; mean age 40+/-14 years, range 13-70), 51 patients with prosthetic valve(s) (31 women, 20 men; mean age 48+/-13 years, range 21-71) and 102 healthy subjects (68 women, 34 men, mean age 41+/-12 years, range 25-73), as a control group, were assessed. Patients with acute rheumatic fever, acute infection, inflammatory disease, malignancy, acute myocardial infarction and trauma were excluded. hs-CRP was determined using latex-enhanced immunonephelometric assays on a BN II analyzer (Behring). Transthoracic echocardiography was performed in all patients in order to evaluate valvular disease. Levels of hs-CRP were significantly higher in patients with chronic rheumatic heart disease than in patients with prosthetic valve(s) and healthy subjects (0.62+/-0.64 vs. 0.35+/-0.41 vs. 0.24+/-0.18 mg/l, P<0.01 and P<0.001 respectively). No correlation was observed between CRP and age, sex or functional capacity. We found that hs-CRP is increased in chronic rheumatic heart disease; this may indicate that inflammatory response still persists in the chronic phase.

Quantitative analysis of human heart valves: does anorexigen exposure produce a distinctive morphological lesion?

The need for more detail regarding the clinical and morphological features of human heart valves has become evident due to recent controversy regarding anorexigen-associated valvular dysfunction. In the present study, we used quantitative digital image analysis of geometric and compositional features to compare the histopathology of cardiac valves excised from patients treated with anorexigens as compared to normal, floppy, rheumatic and carcinoid valves. Anorexigen-exposed valves had the greatest number of onlays/valve (P<.0001), while rheumatic valves showed the greatest average onlay size and thickness of the comparison groups studied (P=.01). The valve onlays from anorexigen-exposed, carcinoid and floppy valves contained a greater percentage of glycosaminoglycans (GAGs) as compared to normal and rheumatic valves (P=.01). The anorexigen-exposed valve propers contained more GAGs than any other comparison group (P=.02). Vessels were prominent in both onlay and valve proper regions of carcinoid valves, in the anorexigen-exposed valve onlays and in rheumatic valve propers. Thus, the number of onlays, their size, the degree of GAG deposition, and the presence and location of vessels and leukocytes were important features distinguishing anorexigen-exposed valves from normal valves. Discriminant analyses, based on geometry, color composition or color composition, and vessel and leukocyte counts combined, were able to separate the valves into distinguishable groups. Our findings demonstrate that specific microscopic features can be used to separate anorexigen-associated heart valve lesions from normal valves and valve lesions associated with other pathologies, and suggest that a distinctive pathological process may exist in many anorexigen-exposed valves.