Association between transforming growth factor-beta1 gene C-509T and T869C polymorphisms and rheumatic heart disease

Copy number variations within fibroblast growth factor 13 gene influence growth traits and alternative splicing in cattle

Previous researches revealed a copy number variation (CNV) region in the bovine fibroblast growth factor 13 (FGF13) gene. However, its effects remain unknown. This study detected the various copy number types in seven Chinese cattle breeds and analysed their population genetic characteristics and effects on growth traits and transcription levels. Copy number Loss was more frequent in Caoyuan Red cattle and Xianan cattle than in the other breeds. Association analysis between CNV and growth traits of Qinchuan indicated that the CNV was significantly related to chest depth, hip width and hucklebone width (P < 0.05). Additionally, the growth traits of individuals with copy number Loss were significantly inferior to those with copy number Gain or Median (P < 0.05). Besides, we found two splicing isoforms, AS1 and AS2, in FGF13 gene, which resulted from alternative 5' splicing sites of intron 1. These isoforms showed varied expression levels in various tissues. Moreover, CNV was significantly and negatively associated with the mRNA expression of AS1 (r = -0.525, P < 0.05). The CNVs in bovine FGF13 gene negatively regulated growth traits and gene transcription. These observations provide new insights into bovine FGF13 gene, delivering potentially useful information for future Chinese cattle breeding programs.

Lifestyle patterns, genetic susceptibility, and risk of valvular heart disease: a prospective cohort study based on the UK Biobank

AIMS

Genetic and lifestyle factors are both major contributors to valvular heart disease (VHD). However, it is still uncertain whether genetic susceptibility alters the association between lifestyle and VHD. We aimed to investigate the association between lifestyle and VHD in different genetic risk backgrounds.

METHODS AND RESULTS

A prospective cohort study was carried out on 499 341 participants without VHD at baseline. The assessment of lifestyle included smoking, alcohol consumption, diet, activity, and sleep. Genetic susceptibility was separately measured by polygenic risk scores (PRSs) and family history of cardiovascular disease (CVD). Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (95%CIs) between lifestyle and VHD, as well as aortic stenosis (AS). During a median follow-up of 10.8 years, 12 983 incident VHD cases were diagnosed (incidence rate 2.46 per 1000 person-years), including 3527 AS cases (incidence rate 0.66 per 1000 person-years). The risk of VHD and AS decreased with healthier lifestyles (P value for trend <0.001). Compared to individuals with a unhealthy lifestyle, the HRs of VHD in intermediate and healthy lifestyle groups were 0.81 (0.76-0.86) and 0.81 (0.76-0.87). The negative association between healthy lifestyle and VHD events was independent of genetic risk (P for interaction between healthy lifestyle scores and PRSs/family history of CVD was 0.723/0.763). Similar findings were obtained in analyses of AS, and a stronger negative association was found.

CONCLUSION

Our study reveals that adherence to a healthy lifestyle is significantly associated with a reduced risk of VHD especially AS, irrespective of genetic susceptibility.

SUMMARY

Based on a cohort of around 490 000 participants, the study investigated the association between lifestyle and VHD under different stratifications of genetic risk. The study found that a healthy lifestyle was associated with a lower risk of VHD, particularly AS, independent of genetic risk. Our findings suggest that advance interventions for lifestyle may be an effective way to reduce the global burden of VHD.

Atypical Expression of Smooth Muscle Markers and Co-activators and Their Regulation in Rheumatic Aortic and Calcified Bicuspid Valves

Objective

We have previously reported that human calcified aortic cusps have abundant expression of smooth muscle (SM) markers and co-activators. We hypothesised that cells in bicuspid aortic valve (BAV) cusps and those affected by rheumatic heart valve (RHV) disease may follow a similar phenotypic transition into smooth muscle cells, a process that could be regulated by transforming growth factors (TGFs).

Aims

Cusps from eight patients with BAV and seven patients with RHV were analysed for early and late SM markers and regulators of SM gene expression by immunocytochemistry and compared to healthy aortic valves from 12 unused heart valve donors. The ability of TGFs to induce these markers in valve endothelial cells (VECs) on two substrates was assessed.

Results

In total, 7 out of 8 BAVs and all the RHVs showed an increased and atypical expression of early and late SM markers α-SMA, calponin, SM22 and SM-myosin. The SM marker co-activators were aberrantly expressed in six of the BAV and six of the RHV, in a similar regional pattern to the expression of SM markers. Additionally, regions of VECs, and endothelial cells lining the vessels within the cusps were found to be positive for SM markers and co-activators in three BAV and six RHV. Both BAVs and RHVs were significantly thickened and HIF1α expression was prominent in four BAVs and one RHV. The ability of TGFβs to induce the expression of SM markers and myocardin was greater in VECs cultured on fibronectin than on gelatin. Fibronectin was shown to be upregulated in BAVs and RHVs, within the cusps as well as in the basement membrane.

Conclusion

Bicuspid aortic valves and RHVs expressed increased numbers of SM marker-positive VICs and VECs. Concomittantly, these cells expressed MRTF-A and myocardin, key regulators of SM gene expression. TGFβ1 was able to preferentially upregulate SM markers and myocardin in VECs on fibronectin, and fibronectin was found to be upregulated in BAVs and RHVs. These findings suggest a role of VEC as a source of cells that express SM cell markers in BAVs and RHVs. The similarity between SM marker expression in BAVs and RHVs with our previous study with cusps from patients with aortic stenosis suggests the existance of a common pathological pathway between these different pathologies.

Functional nucleotide polymorphisms up-regulating transforming growth factor β1 expression are associated with increased tuberculosis susceptibility

Previous studies demonstrated that transforming growth factor (TGT) β1 plays an immunosuppressive role in clinical tuberculosis. However, the contribution of TGF-β1 gene polymorphisms to human tuberculosis susceptibility remains undetermined. In this study, we showed that single-nucleotide polymorphisms (SNPs) in TGF-β1 gene were associated with increased susceptibility to tuberculosis in the discovery cohort (1533 case patients and 1445 controls) and the validation cohort (832 case patients and 1084 controls), and 2 SNPs located in the promoter region (rs2317130 and rs4803457) are in strong linkage disequilibrium. The SNP rs2317130 was associated with the severity of tuberculosis. Further investigation demonstrated that rs2317130 CC genotype is associated with higher TGF-β1 and interleukin 17A production. The mechanistic study showed that rs2317130 C allele affected TGF-β1 promoter activity by regulating binding activity to nuclear extracts. These findings provide insights into the pathogenic role of TGF-β1 in human tuberculosis and reveal a function for the TGF-β1 promoter SNPs in regulating immune responses during Mycobacterium tuberculosis infection.

Genetic variants in rheumatic fever and rheumatic heart disease

Genetic association studies in rheumatic heart disease (RHD) have the potential to contribute toward our understanding of the pathogenetic mechanism, and may shed light on controversies about RHD etiology. Furthermore, genetic association studies may uncover biomarkers that can be used to identify susceptible individuals, and contribute toward developing vaccine and novel therapeutic targets. Genetic predisposition to rheumatic fever and RHD has been hypothesized by findings from familial studies and observed associations between genes located in the human leukocyte antigens on chromosome 6p21.3 and elsewhere in the genome. We sought to summarize, from published Genetic association studies in RHD, evidence on genetic variants implicated in RHD susceptibility. Using HuGENet™ systematic review methods, we evaluated 66 studies reporting on 42 genes. Existing meta-analyses of candidate gene studies suggest that TGF-β1 [rs1800469], and IL-1β [rs2853550] single nucleotide polymorphisms (SNPs) contribute to susceptibility to RHD, whereas the TNF-α [rs1800629 and rs361525], TGF-β1 [rs1800470 and rs4803457], IL-6 [rs1800795], IL-10 [rs1800896] were not associated with RHD. However, candidate gene studies in RF/RHD are relatively small, thus lacking statistical power to identify reliable and reproducible findings, emphasizing the need for large-scale multicenter studies with different populations.

Association between host TNF-α, TGF-β1, p53 polymorphisms, HBV X gene mutation, HBV viral load and the progression of HBV-associated chronic liver disease in Indonesian patients

In developing countries, including Indonesia, there is a high mortality rate associated with the progression of hepatitis B virus (HBV)-associated chronic liver disease (CLD). The pathogenesis of HBV infection is influenced by viral and host factors. To determine potential associations between these factors, host single nucleotide polymorphisms (SNPs) on TNF-α, TGF-β1 and p53, HBV X gene mutation and HBV viral load were investigated in patients with HBV-associated CLD in Surabaya, Indonesia. Sera were collected from 87 CLD patients with HBV infection. TNF-α, TGF-β1 and p53 SNPs were genotyped by PCR restriction fragment length polymorphism. The HBV X gene was sequenced and compared with reference strains to determine mutations and the viral load was measured using reverse transcription-quantitative PCR. In Indonesian patients, no association between TNF-α, TGF-β1 and p53 SNPs and CLD or X gene mutation were identified. A total of 23% (20/87) of samples had HBV X gene mutations, including ten substitution types, one deletion and one insertion. Multinomial regression analysis revealed that the K130M/V131I mutations were correlated with CLD progression (OR, 7.629; 95% CI, 1.578-36.884). Significant differences in viral load were found in HBV-infected patients who had X gene mutations, such as R87W/G, I127L/T/N/S and K130M/V131I mutations (P<0.05). The presence of K130M and V131I mutations may be predictive for the progression of HBV-associated CLD in Indonesia.

T cell subsets: an integral component in pathogenesis of rheumatic heart disease

Acute rheumatic fever (ARF) is a consequence of pharyngeal infection of group A streptococcal (GAS) infection. Carditis is the most common manifestation of ARF which occurs in 30-45% of the susceptible individuals. Overlooked ARF cases might further progress towards rheumatic heart disease (RHD) in susceptible individuals, which ultimately leads to permanent heart valve damage. Molecular mimicry between streptococcal antigens and human proteins is the most widely accepted theory to describe the pathogenesis of RHD. In the recent past, various subsets of T cells have been reported to play an imperative role in the pathogenesis of RHD. Alterations in various T cell subsets, viz. Th1, Th2, Th17, and Treg cells, and their signature cytokines influence the immune responses and are associated with pathogenesis of RHD. Association of other T cell subsets (Th3, Th9, Th22, and T_FH) is not defined in context of RHD. Several investigations have confirmed the up-regulation of adhesion molecules and thus infiltration of T cells into the heart tissues. T cells secrete both Th type 1 and type 2 cytokines and these auto-reactive T cells play a key role in progression of heart valve damage. In this review, we are going to discuss about the role of T cell subsets and their corresponding cytokines in the pathogenesis of RHD.

Streptococcal pharyngitis and rheumatic heart disease: the superantigen hypothesis revisited

Streptococcus pyogenes is a human-specific and globally prominent bacterial pathogen that despite causing numerous human infections, this bacterium is normally found in an asymptomatic carrier state. This review provides an overview of both bacterial and human factors that likely play an important role in nasopharyngeal colonization and pharyngitis, as well as the development of acute rheumatic fever and rheumatic heart disease. Here we highlight a recently described role for bacterial superantigens in promoting acute nasopharyngeal infection, and discuss how these immune system activating toxins could be crucial to initiate the autoimmune process in rheumatic heart disease.

Update on rheumatic heart disease

PURPOSE OF REVIEW

The purpose is to provide a broad overview of the current state of knowledge of pathogenesis, diagnosis, and management of rheumatic heart disease (RHD).

RECENT FINDINGS

Studies on pathogenesis of RHD have focused on autoimmunity because of molecular mimicry between the streptococcal M antigen α-helical coiled-coil structure and sarcomeric proteins such as myosin and tropomyosin. More recently, nonsarcomeric autoantigens, endothelial injury and the innate immune system have been proposed to play key roles in the pathogenesis of RHD. In the 2015 revised Jones Criteria, the importance of echocardiography and subclinical carditis in the diagnosis of acute rheumatic fever is highlighted. Experimental studies with targeted anti-inflammatory therapeutics have been largely unsuccessful and the only established treatment is still lifelong antibiotics. Efforts to improve patient selection and outcomes with percutaneous mitral balloon valvuloplasty are ongoing. With regard to surgical management, several groups have demonstrated excellent operative and midterm outcomes from valve repair as opposed to valve replacement.

SUMMARY

There are still many unanswered questions regarding RHD pathogenesis. The only accepted medical treatment is still long-term antibiotic therapy, whereas advances in mitral repair techniques have led to successful durable repairs being performed in high-volume, expert centers.

Association study of inflammatory genes with rheumatic heart disease in North Indian population: A multi-analytical approach

Rheumatic heart disease (RHD) is an inflammatory, autoimmune disease; occurring as a consequence of group A streptococcal infection complicated by rheumatic fever (RF). An inappropriate immune response is the central signature tune to the complex pathogenesis of RHD. However, some of those infected develop RHD, and genetic host susceptibility factors are thought to play a key role in diseasedevelopment. Therefore, the present study was designed to explore the role of genetic variants in inflammatory genes in conferring risk of RHD. The study recruited total of 700 subjects, including 400 RHD patients and 300 healthy controls. We examined the associations of 8 selected polymorphisms in seven inflammatory genes: IL-6 [rs1800795G/C], IL-10 [rs1800896G/A], TNF-A [rs1800629G/A], IL-1β [rs2853550C/T], IL-1VNTR [rs2234663], TGF-β1 [rs1800469C/T]; [rs1982073T/C], and CTLA-4 [rs5742909C/T] with RHD risk. Genotyping for all the polymorphisms was done using PCR-ARMS/PCR/RFLP methods. Multifactor dimensionality reduction and classification and regression tree approaches were combined with logistic regression to discover high-order gene-gene interactions in studiedgenes involved in RHD susceptibility.In univariate logistic regression analysis, we found significant association of variant-containing genotypes (CT&TT) of TGF-β1 869T/C [rs1982073]; [p=0.0.004 & 0.001, OR (95% CI)=1.65 (1.2-2.3) & 2.25 (1.4-3.6) respectively], variant genotype (CC) of IL-1β -511C/T [rs2853550]; [p=0.001, OR (95% CI)=2.33 (1.4-3.8)] and IL-1 VNTR [rs2234663]; [p=0.03, OR (95% CI)=5.25 (1.2-23.4)] SNPs with RHD risk. CART analysis revealed that individuals with the combined genotypes of TGF-β1T/C_ rs1982073 (CT/TT) and IL-1 β_ rs2853550 (CC) had significantly higher susceptibility for RHD [p=0.0005, OR (95% CI)=5.91 (2.9-12.5)]. In MDR analysis, TGF-β1 869T>C yielded the highest testing accuracy of 0.562. In conclusion, using multi-analytical approaches, our study revealed important role of TGF-β1 869T/C [rs1982073] in RHD susceptibility.

Rheumatic heart disease in Africa: is there a role for genetic studies?

Rheumatic heart disease (RHD) constitutes a leading cause of premature death and incapacity in Africa, where it is encountered in younger people, and shows a much faster and more malignant course than that seen in Europe or North America. While it is well established that RHD is a consequence of recurrent, untreated group A β-haemolytic streptococcal infections (GAS), the pathogenesis is incompletely understood, and the variation in natural history and phenotypes are not fully explained. In Africa patients are rarely diagnosed with acute rheumatic fever (ARF). They usually present in the late stages of RHD, with the severe and virulent forms occurring at early ages, therefore leading to high morbidity and mortality in young patients.

Acute rheumatic fever and rheumatic heart disease

Acute rheumatic fever (ARF) is the result of an autoimmune response to pharyngitis caused by infection with group A Streptococcus. The long-term damage to cardiac valves caused by ARF, which can result from a single severe episode or from multiple recurrent episodes of the illness, is known as rheumatic heart disease (RHD) and is a notable cause of morbidity and mortality in resource-poor settings around the world. Although our understanding of disease pathogenesis has advanced in recent years, this has not led to dramatic improvements in diagnostic approaches, which are still reliant on clinical features using the Jones Criteria, or treatment practices. Indeed, penicillin has been the mainstay of treatment for decades and there is no other treatment that has been proven to alter the likelihood or the severity of RHD after an episode of ARF. Recent advances - including the use of echocardiographic diagnosis in those with ARF and in screening for early detection of RHD, progress in developing group A streptococcal vaccines and an increased focus on the lived experience of those with RHD and the need to improve quality of life - give cause for optimism that progress will be made in coming years against this neglected disease that affects populations around the world, but is a particular issue for those living in poverty.

Post-infectious group A streptococcal autoimmune syndromes and the heart

There is a pressing need to reduce the high global disease burden of rheumatic heart disease (RHD) and its harbinger, acute rheumatic fever (ARF). ARF is a classical example of an autoimmune syndrome and is of particular immunological interest because it follows a known antecedent infection with group A streptococcus (GAS). However, the poorly understood immunopathology of these post-infectious diseases means that, compared to much progress in other immune-mediated diseases, we still lack useful biomarkers, new therapies or an effective vaccine in ARF and RHD. Here, we summarise recent literature on the complex interaction between GAS and the human host that culminates in ARF and the subsequent development of RHD. We contrast ARF with other post-infectious streptococcal immune syndromes - post-streptococcal glomerulonephritis (PSGN) and the still controversial paediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS), in order to highlight the potential significance of variations in the host immune response to GAS. We discuss a model for the pathogenesis of ARF and RHD in terms of current immunological concepts and the potential for application of in depth "omics" technologies to these ancient scourges.

Evaluation of interleukin-1α, interleukin-10, tumor necrosis factor-α and transforming growth factor-β in the serum of patients with pemphigus vulgaris

Pemphigus is an autoimmune blistering disease characterized by a loss of cell adhesion result in acantholysis. Genetic factors and immunologic factors such as cytokines particularly IL-1α, IL-10, TNF-α, and TGF-β may counterpart to developing of Pemphigus. The aim of this study was to evaluate. The concentration of IL-1α, IL-10, TNF-α, TGF-β in serum of pemphigus vulgaris (PV) patients and normal individuals.

MATERIAL AND METHODS

In this analytic and descriptive study 25 patients with pemphigus vulgaris (in active phase) and 25 healthy per sons were examined. Serum samples of two groups were obtained and the level of IL-1α, IL-10, TNF-α and TGF-β were measured by ELISA technique. The data were analyzed statistically by independent T test (α = 0/05).

RESULTS

All cytokines tested, showed higher concentration in patient's sera comparing to healthy control individuals. The level of IL-1α (p = 0.004), TNF-α (p = 0.008) and TGF-β (p = 0.009) were statistically different in two experimental groups, There was no significant difference in IL-10 level (p = 0.605).

CONCLUSION

Cytokines such as IL-1α, IL-10, TNF-α and TGF-β probably have a role in pathogenesis of PV. Further comprehensive studies are suggested to confirm these findings.

The association between the C-509T and T869C polymorphisms of TGF-β1 gene and the risk of asthma: a meta-analysis

Asthma is a complex multigenic disease in which gene-environment interactions play a critical role in disease onset and progression. Transforming growth factor-β1 (TGF-β1) is one of several candidate locus for the pathogenesis of asthma, and is highly polymorphic. To derive a more precise estimation of the relationship between the T869C and C-509T polymorphisms of the TGF-β1 gene and asthma, a meta-analysis of 24 published case-control studies was conducted. 20 studies for C-509T polymorphism and 8 studies for T869C polymorphism were included. The pooled odds ratios were calculated respectively for allele contrasts, additive genetic model, dominant genetic model and recessive genetic model. Subgroup analyses were also performed by ethnicity, age, atopic status and asthma severity for two gene polymorphisms. In regard to T869C polymorphism, significant associations with asthma were observed in recessive (OR 1.23, 95%CI 1.00-1.51 and P=0.047), additive and allele models. In the subgroup analysis by age, significant risks were also found in the recessive model for adults (OR 1.31, 95%CI 1.02-1.69 and P=0.032), atopic asthma (OR 1.63, 95%CI 1.07-2.49 and P=0.023). With respect to C-509T polymorphism, significant associations with asthma were demonstrated in the overall analysis and subgroup analyses in the dominant model for Asian (OR 1.37, 95%CI 1.04-1.81 and P=0.025), Adults (OR 1.26, 95%CI 1.02-1.56 and P=0.035), Children (OR 1.19, 95%CI 1.01-1.40 and P=0.034). Potentially functional TGF-β1 C-509T and T869C polymorphisms may be risk factors for asthma susceptibility.

Evaluation of circulating Transforming growth factor-beta1, Glypican-3 and Golgi protein-73 mRNAs expression as predictive markers for hepatocellular carcinoma in Egyptian patients

Hepatocellular carcinoma (HCC) incidence is fast-growing especially in countries highly prevalent with viral hepatitis. Its poor prognosis has driven the research toward the discovery of sensitive markers for early detection. We investigated the usefulness of serum Transforming growth factor-beta1 (TGF-β1), Glypican-3 (GPC3), and Golgi protein-73 (GP73) mRNAs as early biomarkers in HCC Egyptian patients chronically infected with hepatitis C virus (HCV) in comparison with serum alpha-fetoprotein (AFP). Using semi-quantitative RT-PCR and densitometry analysis, circulating TGF-β1, GPC3, and GP73 mRNAs expressions were estimated in 15 healthy adults, 15 chronic HCV (CHC) patients and 25 HCC patients. Serum GP73 expression percentage in HCC group was significantly higher than controls (100 vs. 40 %, P ≤ 0.001) and when compared to elevated serum AFP levels (100 vs. 36 %, P ≤ 0.001). TGF-β1 and GP73 expression means were also higher in HCC patients than controls and CHC patients (P < 0.05). GPC3 expression showed higher frequency in CHC patients compared to HCC group (80 vs. 28 %, P = 0.0016). According to the study cutoffs, serum TGF-β1 and GP73 mRNAs showed 60 and 96 % sensitivities for HCC diagnosis with 100 and 95 % specificities, respectively. Furthermore, elevated GP73 mRNA expression levels in early HCC were significantly increased compared to those of TGF-β1 mRNA and to high serum AFP (92.3 vs. 53.8 and 23.1 %; P = 0.03 and 0.0004, respectively). In conclusion, circulating TGF-β1 and GP73 mRNAs could be useful biomarkers for HCV-induced HCC diagnosis. Moreover, serum GP73 mRNA is sensitive for early cancer detection than AFP and TGF-β1 mRNA. However, these results need further validation studies.

Rheumatic Heart Disease: Molecules Involved in Valve Tissue Inflammation Leading to the Autoimmune Process and Anti-S. pyogenes Vaccine

The major events leading to both rheumatic fever (RF) and rheumatic heart disease (RHD) are reviewed. Several genes are involved in the development of RF and RHD. The inflammatory process that results from S. pyogenes infection involves the activation of several molecules such as VCAM and ICAM, which play a role in the migration of leukocytes to the heart, particularly to the valves. Specific chemokines, such as CXCL3/MIP1α as well as CCL1/I-309 and CXCL9/Mig, attract T cells to the myocardium and valves, respectively. The autoimmune reactions are mediated by both the B- and T-cell responses that begin at the periphery, followed by the migration of T cell clones to the heart and the infiltration of heart lesions in RHD patients. These cells recognize streptococcal antigens and human-tissue proteins. Molecular mimicry between streptococcal M protein and human proteins has been proposed as the triggering factor leading to autoimmunity in RF and RHD. The production of cytokines from peripheral and heart-infiltrating mononuclear cells suggests that T helper 1 and Th17 cytokines are the mediators of RHD heart lesions. The low numbers of IL-4 producing cells in the valvular tissue might contribute to the maintenance and progression of the valve lesions. The identification of a vaccine epitope opens a perspective of development of an effective and safe vaccine to prevent S. pyogenes infections, consequently RF and RHD.

Inflammatory biomarkers for predicting cardiovascular disease

The pathology of cardiovascular disease (CVD) is complex; multiple biological pathways have been implicated, including, but not limited to, inflammation and oxidative stress. Biomarkers of inflammation and oxidative stress may serve to help identify patients at risk for CVD, to monitor the efficacy of treatments, and to develop new pharmacological tools. However, due to the complexities of CVD pathogenesis there is no single biomarker available to estimate absolute risk of future cardiovascular events. Furthermore, not all biomarkers are equal; the functions of many biomarkers overlap, some offer better prognostic information than others, and some are better suited to identify/predict the pathogenesis of particular cardiovascular events. The identification of the most appropriate set of biomarkers can provide a detailed picture of the specific nature of the cardiovascular event. The following review provides an overview of existing and emerging inflammatory biomarkers, pro-inflammatory cytokines, anti-inflammatory cytokines, chemokines, oxidative stress biomarkers, and antioxidant biomarkers. The functions of each biomarker are discussed, and prognostic data are provided where available.

Association of angiotensin I-converting enzyme gene insertion/deletion polymorphism with rheumatic heart disease in Indian population and meta-analysis

Rheumatic heart disease (RHD) is one of the most severe consequences of rheumatic fever. It has been suggested that angiotensin I-converting enzyme (ACE) may be involved in the increased valvular fibrosis and calcification in the pathogenesis of RHD. We conducted a case-control study to look for association of ACE I/D polymorphism with RHD in Indian population. The study incorporated 300 patients (170 males and 130 females) with RHD, and 200 controls (118 males and 82 females). We also subgrouped RHD patients into mitral valve lesion (MVL) and combined valve lesion (CVL). ACE I/D polymorphism was identified using polymerase chain reaction method. We also performed a meta-analysis of three published studies and the present study (636 RHD cases and 533 controls) to evaluate the association between the ACE I/D polymorphisms and RHD risk. A significant difference in ACE ID and DD genotypes distribution between RHD cases (OR = 1.62, 95% CI = 1.11-2.36 and OR = 2.08, 95% CI = 1.02-4.15, respectively) and corresponding controls was observed. On comparing the ACE genotypes of MVL and CVL subgroups with controls, ID and DD genotypes were also significantly associated with CVL (FDR Pcorr = 0.009, OR = 2.19 and FDR Pcorr = 0.014, OR = 3.29, respectively). Meta-analysis also suggested association of the ACE D allele (FDR Pcorr = 0.036, OR-1.22, 95% CI 1.02-1.45) with RHD. In conclusion, ACE ID and DD genotypes are associated with an increased risk of RHD, particularly CVL. This suggests that the ACE I/D gene polymorphism may play an important role in the pathogenesis of RHD.

Role of cytokine gene (IFN-γ, TNF-α, TGF-β1, IL-6, and IL-10) polymorphisms in pathogenesis of acute rheumatic fever in Turkish children

Acute rheumatic fever (ARF) is a delayed immunologically mediated sequela of throat infection by group A β-hemolytic streptococci. Inflammatory cytokines may play a pathogenic role in ARF. The objective of this study was to investigate the potential associations between interferon (IFN)-γ, interleukin (IL)-6, tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, and IL-10 gene polymorphisms and childhood ARF. Thirty-eight ARF patients and 40 age- and sex-matched healthy controls were analyzed for eight polymorphisms in five different cytokine genes [IFN-γ (+874), IL-6 (-174), TNF-α (-308), TGF-β1 (+10, +25), and IL-10 (-1082, -819, -592)]. Cytokine genotyping was performed by polymerase chain reaction sequence-specific primer methods. Patients with ARF had significantly higher frequencies of IFN-γ (+874) polymorphism in both TT genotype (p=0.0002) and T allele (p=0.0004). No statistically significant differences were observed in genotypes, haplotypes, and allele frequencies of IL-6, TNF-α, TGF-β1, and IL-10 genes between ARF and control groups (p>0.05). GG genotype frequency of TNF-α gene (low expression) was higher in patients who had previous ARF history (p=0.006). High expression of TGF-β1 (TT/GG, TC/GG) was more frequent in patients with CRP positivity (p=0.034). IL-6 CC genotype (low expression) frequency was higher in patients with tricuspid valve insufficiency (p=0.002), while IFN-γ TT genotype (high expression) frequency was higher in patients with mitral valve prolapse (p=0.049).

CONCLUSION

High expression of the IFN-γ gene may carry a higher risk for ARF in Turkish children, while IL-6, TNF-α, and TGF-β1 may have an impact in mediating some clinical and laboratory manifestations of the disease.

Understanding rheumatic fever

Through a comprehensive review of the recent findings on rheumatic fever, we intend to propose a new physiopathologic model for this disease. A Medline search was performed for all articles containing the terms rheumatic fever or rheumatic heart disease in title or abstract from 1970 to 2011. Best evidence qualitative technique was used to select the most relevant. The scientific interest on rheumatic fever has notably diminished throughout the twentieth century as evidenced by the comparison of the proportion of articles in which RF was a subject in 1950 (0.26%) and today (0.03%) [Pubmed]. However, RF remains a major medical and social problem in the developing world and in the so-called hotspots, where it still causes around 500.000 deaths each year, not too different from the pre-antibiotic era. The role of genetic factors in RF susceptibility is discussed. Familiar aggregation, similarity of disease patterns between siblings, identical twin, and HLA correlation studies are evidence for a genetic influence on RF susceptibility. The suspect-involved genes fall mainly into those capable of immunologic mediation. Molecular mimicry explains the triggering of RF, but an intense and sustained inflammation is needed to cause sequels. Also, RF patients vary greatly in terms of symptoms. It is likely that a genetic background directing immune response towards a predominantly Th1 or Th2 pattern contributes to these features. The recent findings on rheumatic fever provide important insight on its physiopathology that helps understanding this prototype post-infectious autoimmune disease giving insights on other autoimmune conditions.

Genes, autoimmunity and pathogenesis of rheumatic heart disease

Pathogenesis of rheumatic heart disease (RHD) remains incompletely understood. Several genes associated with RHD have been described; most of these are involved with immune responses. Single nucleotide polymorphisms in a number of genes affect patients with RHD compared to controls. Molecular mimicry between streptococcal antigens and human proteins, including cardiac myosin epitopes, vimentin and other intracellular proteins is central to the pathogenesis of RHD. Autoreactive T cells migrate from the peripheral blood to the heart and proliferate in the valves in response to stimulation with specific cytokines. The types of cells involved in the inflammation as well as different cytokine profiles in these patients are being investigated. High TNF alpha, interferon gamma, and low IL4 are found in the rheumatic valve suggesting an imbalance between Th1 and Th2 cytokines and probably contributing to the progressive and permanent valve damage. Animal model of ARF in the Lewis rat may further contribute towards understanding the ARF.

Some of the People, Some of the Time

Acute rheumatic fever is a major cause of heart disease in large parts of the world, but it remains unknown why only a small fraction of those who are infected with rheumatogenic group A streptococci develop an abnormal immune response that leads to acute rheumatic fever. An understanding of the mechanisms underlying host susceptibility can provide important insights into pathogenesis that in turn can inform new treatments. Extensive searches for susceptibility factors have been undertaken, including human leukocyte antigens, B-cell alloantigens, and cytokine genes. Although significant associations have been found between genetic factors and acute rheumatic fever, study results often conflict with each other. This review explores current understanding about host susceptibility to acute rheumatic fever and provides an overall perspective to the number of studies that have recently addressed this subject.

TGF-beta1 genotypes in cirrhosis: relationship with the occurrence of liver cancer

This study aimed to verify whether specific single nucleotide polymorphisms (SNPs) of the transforming growth factor-beta1 (TGF-beta1) may predispose to end-stage liver disease and/or hepatocellular carcinoma (HCC). One hundred eighty-eight consecutive patients transplanted for liver cirrhosis (HBV N=21, HCV N=68, alcoholic N=55 and others N=23) and a control group of 140 healthy blood donors were investigated. Four SNPs were studied by restriction fragment length assays: -800G>A, -509C>T, Leu10Pro and Arg25Pro. Patients were found to possess the -509T/ * (TT 53/188, CT 85/188, CC 50/188 vs TT 22/140, CT 61/140, CC 57/140; p<0.002) and Arg25Pro C/ * genotypes (CC 1/188, CG 31/188, GG 156/188 vs CC 0/140, CG 13/140, GG 127/140; p<0.05) more frequently than controls. Patients with cirrhosis complicated by HCC possessed more frequently the Leu10Pro T/ * genotype than patients without HCC (TT 20/54, CT 26/54, CC 8/54 vs TT 31/134, CT 69/134, CC 34/134; p<0.05). The analysis of molecular variance detected significant genotypic differentiations between controls and cirrhotics but not between cirrhotics with or without HCC. In conclusion, TGF-beta1 SNPs probably facilitate the development of liver cirrhosis, while they seem to have a limited role in predicting the occurrence of HCC.

Serum transforming growth factor-beta1 as a risk stratifier of sudden cardiac death

Sudden cardiac death prematurely claims the lives of some 7 million each year worldwide. It occurs primarily in patients with an underlying structural cardiac abnormality, and regardless of the type of the underlying pathology (heart failure, dilated and hypertrophic cardiomyopathies, myocardial infarction and aging), death is almost always caused by ventricular tachycardia (VT) which rapidly degenerates to ventricular fibrillation (VF). Implantable cardioverter defibrillator is an effective but expensive therapy for preventing SCD, and finding a reasonably specific, sensitive and cost-effective risk stratification tool for patients at high risk of sudden cardiac death will have great clinical utility in preventing premature sudden cardiac death. Increased myocardial fibrosis has been shown to develop in a wide range of cardiac diseases all manifesting increased risk of VT and VF. Clinical and experimental studies attribute a major role for fibrosis in the initiation of VT, VF and sudden cardiac death. Transforming growth factor-beta1 (TGF-beta1) has been shown to promote myocardial tissue fibrosis and perhaps more importantly in cardiac conditions associated with increased myocardial fibrosis are shown to be positively correlated with increased serum levels of TGF-beta1. In the present hypothesis we suggest that monitoring the serum levels of TGF-beta1 may be a cost-effective risk stratifier to identify patients at high risk of sudden cardiac death caused by VT and VF.

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.

Genetic polymorphisms and plasma levels of transforming growth factor-beta(1) in Chinese patients with tuberculosis in Hong Kong

Susceptibility to tuberculosis (TB) may be affected by host genetic factors. Elevated levels of transforming growth factor-beta 1 (TGF-beta(1)) were found in plasma of patients with active TB compared with those of healthy contacts. To investigate the association of TGF-beta(1) gene polymorphisms (C-509T and T869C) and plasma levels with the risk of TB in Hong Kong Chinese adults, a case-control study was carried out on 174 active TB patients and 174 healthy controls matched for age, gender and smoking. Blood samples from 180 blood donors served as another control group. Genotyping was carried out on genomic DNA using polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Plasma TGF-beta(1) was measured by commercially available ELISA kit. We found no differences in the distribution of genotypes or alleles of TGF-beta(1) gene polymorphisms at C-509T and T869C between patients and either group of healthy controls. Patients with TB had elevated plasma TGF-beta(1) levels compared with healthy controls irrespective of their genotypes (p<0.001). In conclusion, TGF-beta(1) gene polymorphism at C-509T and T869C is not associated with TB susceptibility in Hong Kong Chinese adults, but elevated plasma TGF-beta(1) levels suggests that this cytokine may play a role in the pathogenesis of tuberculosis.

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.

TGF-β1 and TSC-22 Gene Polymorphisms and Susceptibility to Microvascular Complications in Type 2 Diabetes

BACKGROUND/AIM

There is a strong evidence for the involvement of genetic factors in diabetic microvascular complications. The aim of our study was to investigate the role of molecular variants of the TGF-beta1 (transforming growth factor beta 1) and the TSC-22 (transforming growth factor beta stimulated clone 22) genes in diabetic nephropathy and diabetic retinopathy in type 2 diabetes.

METHODS

A case-control study was conducted in 503 patients and 400 healthy subjects. DNA samples were genotyped by polymerase chain reaction and restriction fragment length polymorphism methods.

RESULTS

Among the patients, 245 had diabetic nephropathy, 195 had retinopathy, and 168 were free from complications. All subjects were genotyped for T869C and C -509T polymorphisms of the TGF-beta1 gene and for -396 polymorphism of the TSC-22 gene. A significantly increased frequency of the CC genotype of the T869C polymorphism was observed in patients with nephropathy and retinopathy (33 and 48%, respectively, vs. 19 and 15%, respectively, in controls and patients free from complications). The frequency of the C allele was also higher (0.58 for nephropathy and 0.64 for retinopathy vs. 0.42 in controls). The G allele of the TSC-22 polymorphism was associated with an increased risk of diabetic nephropathy (frequency 0.15 vs. 0.07 and 0.06, respectively, in patients free from complications and controls). An interaction was observed between the G allele of the TSC-22 polymorphism and the C-allele of the TGF-beta polymorphism.

CONCLUSIONS

Our data suggest the association of TGF-beta T869C gene polymorphism with an increased risk of nephropathy and retinopathy in type 2 diabetes patients. It interacts with the TSC-22 gene involved in the TGF-beta signaling pathway, promoting the development of diabetic nephropathy.

Fibrosis in heart disease: understanding the role of transforming growth factor-beta in cardiomyopathy, valvular disease and arrhythmia

The importance of fibrosis in organ pathology and dysfunction appears to be increasingly relevant to a variety of distinct diseases. In particular, a number of different cardiac pathologies seem to be caused by a common fibrotic process. Within the heart, this fibrosis is thought to be partially mediated by transforming growth factor-beta1 (TGF-beta1), a potent stimulator of collagen-producing cardiac fibroblasts. Previously, TGF-beta1 had been implicated solely as a modulator of the myocardial remodelling seen after infarction. However, recent studies indicate that dilated, ischaemic and hypertrophic cardiomyopathies are all associated with raised levels of TGF-beta1. In fact, the pathogenic effects of TGF-beta1 have now been suggested to play a major role in valvular disease and arrhythmia, particularly atrial fibrillation. Thus far, medical therapy targeting TGF-beta1 has shown promise in a multitude of heart diseases. These therapies provide great hope, not only for treatment of symptoms but also for prevention of cardiac pathology as well. As is stated in the introduction, most reviews have focused on the effects of cytokines in remodelling after myocardial infarction. This article attempts to underline the significance of TGF-beta1 not only in the post-ischaemic setting, but also in dilated and hypertrophic cardiomyopathies, valvular diseases and arrhythmias (focusing on atrial fibrillation). It also aims to show that TGF-beta1 is an appropriate target for therapy in a variety of cardiovascular diseases.

Inverse relationship between the ratio of ICAM-1 expressing lymphocytes and serum TGF-β1 concentrations in acute rheumatic fever

Autoimmunity in acute rheumatic fever (ARF) is triggered by group-A beta hemolytic streptococci (GAS). Although most of the recent work has focused on the major impact of lymphocytes, the exact immunopathogenesis is still unresolved. Regulation of self-tolerance in response to GAS has been investigated in various animal experiments. This study aimed to associate the ratio of lymphocytes bearing adhesion/costimulatory molecules, Bcl-2/CD95 and serum TGF-beta1 concentrations with clinical stages of ARF. Thirty-five patients were assigned according to the clinical stages. Bcl-2 expression on CD19+ and CD3+ lymphocytes was similar within patient groups and controls. CD62p expression was higher in patients with carditis. The ratio of ICAM-1 bearing lymphocytes was significantly different between patient groups and controls and was increased through acute to remission stages longitudinally. In contrast, a gradual and significant decrease in TGF-beta1 concentrations was observed longitudinally from acute to chronic stages. A positive correlation has been documented between ICAM-1+ lymphocyte ratios and Fas+ cytotoxic T cell ratios supported by a prominent increase in CD95+ T cells. These data draw our attention to the role of ICAM-1, Fas and TGF-beta1 in ARF pathogenesis through the perspective of self-tolerance in a clinical setting.

Acute rheumatic fever

Acute rheumatic fever (ARF) and its chronic sequela, rheumatic heart disease (RHD), have become rare in most affluent populations, but remain unchecked in developing countries and in some poor, mainly indigenous populations in wealthy countries. More than a century of research, mainly in North America and Europe, has improved our understanding of ARF and RHD. However, whether traditional views need to be updated in view of the epidemiological shift of the past 50 years is still to be established, and improved data from developing countries are needed. Doctors who work in populations with a high incidence of ARF are adapting existing diagnostic guidelines to increase their sensitivity. Group A streptococcal vaccines are still years away from being available and, even if the obstacles of serotype coverage and safety can be overcome, their cost could make them inaccessible to the populations that need them most. New approaches to primary prevention are needed given the limitations of primary prophylaxis as a population-based strategy. The most effective approach for control of ARF and RHD is secondary prophylaxis, which is best delivered as part of a coordinated control programme.

TLR-2 gene Arg753Gln polymorphism is strongly associated with acute rheumatic fever in children

The recently described family of toll-like receptors (TLRs) is a key player in host immunity by mediating inflammatory reactions against a wide range of pathogens. Mutations and polymorphisms in TLRs have revealed the importance of TLRs in human defence against diseases. TLR-2 is reported to interact with different bacterial structures, including lipoproteins, peptidoglycan and lipoteichoic acid. To assess the role of TLR-2 gene polymorphism in acute rheumatic fever (ARF) etiopathology, 61 independent Caucasian Turkish patients and 91 child and 116 adult controls were studied. Antistreptolycin O, C-reactive protein, sedimentation and white blood cell counts were studied to evaluate the clinical characteristics of the patients. Genomic DNA was extracted from peripheral blood using a standard column extraction technique. The Arg753Gln and Arg677Trp polymorphisms were genotyped by polymerase chain reaction (PCR) restriction fragment length polymorphism. The PCR products for the TLR-2 gene were analysed on 1.5% agarose gel pre-stained with ethidium bromide. Compared with healthy adult controls, the Arg753Arg genotype was significantly decreased in the entire group of ARF cases [odds ratio (OR) 0.01, 95% confidence interval (95% CI) 0.0034-0.031, p<0.0001]. Significantly, ARF patients were just 16 times more frequent with Gln allele (OR 15.6, 95% CI 7.87-30.8, p<0.0001). Moreover, evidence for an intensifying effect of the Gln allele was noteworthy when patients with Arg753Gln genotype were compared with healthy controls (OR 97.1, 95% CI 32.5-290, p<0.0001). However, no Arg677Trp polymorphism was detected in either patients or controls. Our data suggest that there is strong evidence for the biological role of TLR-2 in ARF. The common TLR-2 Arg to Gln polymorphism at position 753 significantly contributes to the pathogenesis of ARF. These results will allow the construction of a profile of individuals prone to ARF and may assist in developing new therapies.

Lack of Association of Genetic Polymorphisms in the Interleukin-1 .BETA., Interleukin-1 Receptor Antagonist, Interleukin-4, and Interleukin-10 Genes With Risk of Rheumatic Heart Disease in Taiwan Chinese

Inflammation and genetics may play a role in the pathogenesis of rheumatic heart disease (RHD). The aim of this study was to test whether interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1Ra), IL-4, or IL-10 gene polymorphisms could be used as markers of susceptibility to or severity of RHD among the Chinese population in Taiwan. A group of 115 patients with RHD diagnosed by echocardiography, and 163 age- and sex-matched normal control subjects were studied. IL-1beta promoter, IL-1beta exon 5, IL-1Ra, IL-4 promoter, IL-4 intron 3, and IL-10 gene polymorphisms were identified by polymerase chain reaction-based restriction analysis. There was no significant difference in the distribution of genotypes and allelic frequencies between RHD cases and controls for IL-1beta promoter, IL-1beta exon 5, IL-1Ra, IL-4 promoter, IL-4 intron 3, and IL-10 gene polymorphisms. Further categorization of the RHD patients into mitral valve disease and combined valve disease subgroups also revealed no statistical difference in these gene polymorphisms when compared with controls. These findings suggest that the IL-1beta, IL-1Ra, IL-4, or IL-10 gene polymorphisms are not suitable genetic markers for RHD in Taiwan Chinese.

Cytokine polymorphisms in patients with pemphigus

The aim of this study was to assess whether tumor necrosis factor alpha (TNF-alpha), transforming growth factor beta1 (TGF-beta1) and interleukin-10 (IL-10) polymorphisms are among the factors influencing the development of pemphigus. Whole blood from 20 patients with pemphigus and 24 control subjects was taken. Genomic DNA was obtained and cytokine genotyping for IL-10 (-1082 G/A; -819 C/T), TGFB1 (codon 10 C/T, codon 25 G/C) and TNFA (-308 G/A) was performed using the ARMS-PCR method. The distribution of IL-10 (-819) alleles was significantly different between the pemphigus and control groups (P=0.009). In particular, allele T was associated with the disease (OR 3.291, 95% CI 1.350-8.020). Similar results were observed when only pemphigus vulgaris (PV) patients were analyzed (P=0.012, OR 3.410, 95% CI 1.346-8.639). An increased frequency of the low producer IL-10 haplotype (-1082/-819 A/T) in patients with pemphigus compared with controls was observed (OR 2.714, 95% CI 1.102-6.685) and this association was also significant when only PV patients were considered (OR 2.667, 95% CI 1.043-6.816). There were no differences between patients and controls in the frequency of any other gene polymorphism analyzed. The increased frequency of the low producer IL-10 haplotype (-1082 /-819 A/T) suggest that the carriage of this haplotype might predispose to pemphigus or the high and intermediate producer haplotypes may be protective factors. The prevalence of the allele IL-10 (-819 T) in pemphigus patients cannot be explained by the current hypothesis, according to which a particular allele of the gene is associated with a different level of cytokine production and therefore affects the predisposition to a particular disease. However, this cytokine polymorphism might be linked to an unknown susceptibility factor.