Candidate gene and genome-wide association studies have led to the discovery of nine loci involved in Mendelian forms of obesity and 58 loci contributing to polygenic obesity. These loci explain a small fraction of the heritability for obesity and many genes remain to be discovered. However, efforts in obesity gene identification greatly modified our understanding of this disorder. In this review, we propose an overlook of major lessons learned from 15 years of research in the field of genetics and obesity. We comment on the existence of the genetic continuum between monogenic and polygenic forms of obesity that pinpoints the role of genes involved in the central regulation of food intake and genetic predisposition to obesity. We explain how the identification of novel obesity predisposing genes has clarified unsuspected biological pathways involved in the control of energy balance that have helped to understand past human history and to explore causality in epidemiology. We provide evidence that obesity predisposing genes interact with the environment and influence the response to treatment relevant to disease prediction.  FTO, PCSK1, MC4R, CTNNBL1) from associated studies at the genome-wide level of significance. The recent emergence of the genome-wide association studies (GWAS) has led to further breakthroughs in gene identification and now nine loci are recognized to be involved in Mendelian forms of obesity along with 58 loci contributing to polygenic obesity. In this review, we will discuss what we have learned from this recent progress in elucidating the molecular basis of obesity. We propose an overlook of major lessons learned from 15 years of research in the field of the genetics and obesity.In 2001, six genes were linked to monogenic human obesity and no common variants were reproducibly associated with polygenic obesity. By 2008, progress in the field led to the discovery of eight monogenic genes and four polygenic genes  have been involved in the two conditions, and this list is likely to grow in the upcoming years. This continuum is not specific to obesity, since one-fifth of the loci that were found to be associated with complex disease traits include a gene that is mutated in a corresponding single-gene disorder [MC4R is illustrative of this point of view. Whereas more than 150 loss-of-function coding mutations have been associated with monogenic obesity [MC4R coding sequence has been associated with a modest increase in the risk for obesity [A striking observation is the existence of a partially overlapping continuum between monogenic and polygenic forms of obesity. Currently, four genes  [FTO variant was associated with increased total and fat dietary intake in children [MC4R was associated with increased feeling of hunger [et al. [SH2B1, KCTD15, MTCH2, NEGR1, BDNF) with dietary intake and nutrient-specific food preference. The association of the two major contributors to polygenic obesity (SNP rs17782313 near  in FTO) , 19 withchildren , 21 as wchildren . The obechildren . The obef hunger , 26, incf hunger , decreasf hunger , 27, the [et al.  recentlyThe genetic dissection of monogenic and polygenic forms of obesity delineate it as an inherited disorder of central regulation of food intake . This isA primary goal of human genetic agnostic approaches such as GWAS is to improve our understanding of the biologic pathways underlying polygenic diseases and traits . A majorFTO story constitutes a textbook case: the FTO gene has been cloned in mice in 1999 [FTO common gene variation and human obesity in 2007  [FTO and obesity-related phenotypes not only in populations of European ancestry but also in African, Asian, South Asian, South American and Pima Indian populations [The  in 1999  but the pathway) , 19. Morulations -36. FTO in humans was not associated with a specific phenotype, and heterozygous loss-of-function mutations are found both in lean and in obese subjects [Fto gene in mice protects from obesity [Fto in mice increases food intake and results in obesity [FTO is a causal gene underlying obesity, and suggest the intronic variant in FTO may increase obesity risk in humans through FTO gain of expression. Expression studies in wild-type rodents have shown that FTO is highly expressed in the hypothalamus and is regulated by feeding and fasting [Fto in the hypothalamus modulates food intake in mice possibly through the leptin / STAT3 signalling pathway [Complete FTO deficiency in humans is associated with an autosomal-recessive lethal syndrome including growth retardation, multiple malformations and premature death, indicating that FTO is essential for normal development of the central nervous and cardiovascular systems in human . Loss ofsubjects . Complet obesity , 38 wher obesity . These d fasting , 40. Ove pathway . in vitro and crystallography studies have shown that FTO is a single-stranded DNA demethylase and is involved in nucleic acid repair or modification processes [FTO intronic SNP is associated with a distinct methylation pattern of a 7.7 kb region at the FTO locus, that includes a highly conserved non-coding element validated as a long-range enhancer [Bioinformatics, rocesses , 42. Therocesses . In lineenhancer . FTO illustrates how human genetic “hypothesis free” approaches can be a catalyst to approaches in functional genomics and the same integrative approach can be applied to other obesity-associated genes markedly increasing our understanding of the physiology of obesity in the upcoming years. The study of Spurious associations in observational epidemiological studies are commonly caused by confounders due to social, behavioral, or environmental factors and can therefore be difficult to control. They may also be due to reverse causation, in which the phenotypic outcome subsequently influences an environmental exposure such that it is wrongly implicated in the pathogenesis. Genetic epidemiology can be used to uncover more thoroughly and more accurately causal factors underlying common diseases or complex traits. The epidemiologic approach with the most promise is often referred to as Mendelian randomization . The priFTO as a major contributor to polygenic variation [et al. [FTO and type 2 diabetes mellitus (T2D) has been observed, suggestive of a causative relationship between weight gain and subsequent T2D development. The same approach, when applied to 12 obesity gene variants, confirmed that the genetic predisposition to obesity leads to an increased risk of developing type 2 diabetes, which is completely mediated by its effect on BMI [FTO genotype has also been used to confirm the findings of observational epidemiology and a causal relationship between BMI increase and altered glucose [FTO SNP as a randomly redistributed variable strengthened the evidence of a causal link between a BMI increase and an increased risk of atherosclerosis [This approach has been successfully used in the obesity arena following the identification of ariation . The Fra [et al.  seminal t on BMI . The FTO glucose , insulin glucose , lipid [ glucose  and bloo glucose . The cau glucose  or incre glucose  has alsoclerosis , cardiovclerosis , endometclerosis , 55 and clerosis , 56. de novo mutations) [LCT) gene confers lactase persistence and carriers of at least one T allele, are able to digest the milk sugar lactose across their life span  [LCT rs4988235 T variant strongly related to events of cattle domestication [LCT rs4988235 T variant has been consistently associated with higher milk consumption [The human genome contains hundreds of regions whose pattern of genetic diversity indicate recent positive natural selection  . Adaptattations) . The tratations) . The “thtations) , was recarriers) , 62. Thetication , 64. A Ntication  as well tication . In linesumption  and withsumption  in EuropLEPR (Lys109Arg), ADRB3 (Trp64Arg) and BDNF  genes previously associated with BMI [FTO, NEGR1, SH2B1 and FAIM2 loci [Interestingly, three functional coding non-synonymous variants in the with BMI , 68, 69,with BMI -72. ReceIM2 loci , 74. MC4R obesity locus has been well documented in the literature. The melanocortin 4 receptor coding sequence has been remarkably conserved in structure and pharmacology for more than 400 million years, implying that this receptor participated in vital physiological functions early in vertebrate evolution [MC4R gene in humans in comparison with primates [MC4R has been subject to high levels of continuous purifying selection that increased threefold during primate evolution [MC4R function to be located at amino acid positions that are highly conserved during the 450 million years of MC4R evolution in vertebrates and subject to very strong purifying selection [The evolutionary history of the volution . There iprimates . The codvolution . Finallyelection .As trends over the past several decades suggest an environmental influence on BMI, many researchers have focused on the identification of specific environmental factors that interact with genetic predisposition to obesity. They based their investigations on epidemiological data showing that physical activity, diet, educational status, age, gender and ethnicity among others modulate the risk for obesity . FTO obesity risk genotype and physical activity on BMI variation or obesity risk including adults as well as adolescents [Recent literature provides firm evidence that genetic susceptibility to obesity can be blunted in part through physical activity. Thirteen independent studies reported an interaction between the lescents -81. Similescents . FTO genotype on obesity risk [APOA2) -265T>C SNP and high-saturated fat in relation to BMI and obesity has been reported in five independent populations [There is also growing evidence that dietary habits interact with genes to modulate predisposition to obesity. Three studies suggest that a high fat diet can amplify the effect of the ity risk -81. An iulations , 84. IntMC4R loss-of function mutation carriers, although a significant relationship was seen in MC4R non-mutation carriers of the corresponding pedigrees [MC4R pathogenic mutations. On the contrary, a significant gene x education interaction has been found for the intron 1 variant in FTO, the significant effect of the SNP on BMI and obesity risk being restricted to subjects with no university education [Epidemiological studies have shown that people with a low level of education are more likely to develop obesity . Howeveredigrees . These rducation . MC4R pathogenic and monogenic mutations on obesity has been found in multigenerational pedigrees, the effect of mutations on the obesity phenotype being amplified by the development of an "obesogenic" environment [MC4R mutation carriers showed an increasing age-dependent penetrance (37% at 20 years versus 60% at >40 years) [FTO gene variant and body mass index in independent longitudinal studies indicates that most of the effect of the SNP on BMI gain occurs during childhood, adolescence and young adulthood [Age-dependent genetic associations have been described both in the context of monogenic and polygenic obesity. An age-dependent penetrance of ironment . The londulthood -89. MC4R pathogenic monogenic mutations since BMI was about twice as strong in females than in males [TBC1D1) gene on severe obesity risk was restricted to females in French and US populations [Gender can be assimilated as a specific environmental condition. Females are at higher risk of developing morbid obesity than males . These din males , 91. Theulations , 93. Sevulations , 95.SIM1 gene. Variants in intronic regions of SIM1 were strongly associated with BMI and obesity risk (P = 4 x 10-7) in Pima Indians contrarily to French Europeans for which a major contribution of SIM1 common variants in polygenic obesity susceptibility was excluded [ADRB3 gene has also been convincingly associated with BMI in East Asian but not in European subjects in a large meta-analysis of 44,833 subjects [th intron of the C12orf51 transcript has been strongly associated with waist to hip ratio (P = 7.8 x 10-12) in the Korean population [Ethnicity can be considered as an environmental factor that affects the genetic susceptibility to obesity. A convincing example of ethnic-specific association with obesity has been reported for the excluded , 97. A fexcluded  in the Asubjects , the effpulation . This vapulation , suggestTo date, three main therapeutic options are proposed to treat obesity: lifestyle intervention, pharmacotherapy and bariatric surgery. The aim of these therapeutics for obesity are to lose weight and maintain this weight-loss on the long term and attenuate co-morbidities related to obesity. There is growing evidence that genetic factors not only predispose to weight gain and development of obesity, but also modulate the response to therapeutic intervention in terms of weight loss. MC4R or POMC monogenic conditions respond well to hypocaloric dietary or multidisciplinary  interventions as do non-monogenic obese subjects [MC4R individuals fail to maintain weight loss after intervention [FTO does not modify the response to lifestyle intervention in terms of weight loss [Individuals withsubjects , 101 butght loss , but mayght loss , 104 or ght loss  to modulin vivo beneficial effects in MC4R deficient monogenic patients remain to be demonstrated.To date, only one successful personalized medicine approach which is based on a genetic diagnosis has been reported in the literature in the context of obesity: individuals with congenital leptin deficiency can be treated with daily injections of recombinant human leptin, which reverses the obesity and associated phenotypic abnormalities . Leptin GNB3) gene C825T polymorphism is highly predictive for the identification of obese individuals who will benefit from sibutramine treatment. Thus, three independent pharmacogenetic studies have shown an association between the GNB3 C825T polymorphism and weight loss induced by sibutramine [To date, the two main anti-obesity drugs used are orlistat and sibutramine . The guanine nucleotide binding protein beta polypeptide 3  [GWAS allowed the identification of 36 polymorphisms robustly associated with BMI. However, identified variants have small effect sizes and collectively explain 1.45% of the variance in BMI  . TherefoO alone) . Risk prO alone) . New iteO alone) , 121. MC4R monogenic mutations, an appropriate medical follow-up to prevent or at least delay the onset of obesity [The cumulative prevalence of monogenic obesity elucidated by the eight currently known genes and the 16p11.2 deletion has not been evaluated in a randomly ascertained cohort of obese subjects to date, but may be estimated between 5 and 10 %. These results re-emphasize the importance of monogenic obesity in elucidating the heritability of obesity, and Mendelian forms of obesity may provide a non-negligible predictive value in classifying young subjects at high risk for the development of childhood obesity, as deleterious coding mutations or chromosomal aberrations in these genes / regions induce highly penetrant forms of obesity. subjects carrying these mutations, present specific features according to the impaired gene  that can guide gene sequencing approaches. Early diagnosis is fundamental for personalized prevention and effective therapeutic management, and in young non-obese individuals carrying  obesity .As hyperphagia is a common feature of monogenic obesity, the most effective preventive strategy may be stringent restriction of food access. This will require training and active participation of the parents and care providers and the identification of critical environmental components  that modulate the penetrance of obesity associated with pathogenic mutations in order to avoid unhealthy environments for these subjects. In conclusion, we have demonstrated that 15 years of gene identification efforts have considerably modified our understanding of the biology of obesity. Promising approaches such as whole-exome and ultimately whole-genome sequencing have the potential to lead to an exhaustive map of obesity predisposing genes in the near future. Recent gene identification efforts have provided a more comprehensive picture of the biological mechanisms involved in the development of obesity and we feel that this information can be meaningful not only for scientists and clinicians but for a more general audience. For instance, the recent discoveries in genetics have found that people differ in their perceptions of hunger and satiety on a genetic basis and that predisposed subgroups of the population may be particularly vulnerable to obesity in “obesogenic” societies with unlimited access to food. This notion must lead to a more open attitude toward obese people and a reduction in discrimination against them , it is c


The Epstein-Barr virus (EBV) double-stranded DNA genome is subject to extensive epigenetic regulation. Large consortiums and individual labs have generated a vast number of genome-wide data sets on human lymphoblastoid and other cell lines latently infected with EBV. Analysis of these data sets reveals important new information on the properties of the host and viral chromosome structure organization and epigenetic modifications. We discuss the mapping of these data sets and the subsequent insights into the chromatin structure and transcription factor binding patterns on latent EBV genomes. Colocalization of multiple histone modifications and transcription factors at regulatory loci are considered in the context of the biology and regulation of EBV. Epstein-Barr virus (EBV) is a human gammaherpesvirus that establishes long-term latent infection in B-lymphocytes ,3. The lTo appreciate the relevance of the EBV epigenome, it is first necessary to highlight some of the major properties of the EBV genome during latency. The type III latency-associated gene expression program in LCLs consists of nine protein coding genes, 21 microRNAs and several non-coding RNAs. The protein coding genes include the Epstein-Barr Nuclear Antigens (EBNAs) EBNA-LP, 1, 2, 3a, 3b and 3c, as well as the Latency Membrane Proteins, LMP1, LMP2a and LMP2b. Two small non-coding RNAs, EBER1 and EBER2, are generated by RNA polymerase III. The miRNAs are generated from two different host transcripts from the BHRF1 or BART regions of the genome . The lathttp://ebv.wistar.upenn.edu). The data deposited to this site include raw alignments, coverage tracks and use original accessions as filenames to ensure reproducible analysis.Epigenetically regulated loci in the EBV genome can be elucidated by high-throughput sequencing data in latently infected human cell lines. Large data sets generated by labs around the world are deposited in standardized databases, such as the NCBI sequence read archive (SRA) and gene expression omnibus (GEO). The raw data can be downloaded and reanalyzed with respect to EBV by aligning the reads to EBV and subtracting any reads that map to the human genome . We haveDue to the small size of the EBV genome relative to the human genome, the alignment can be performed orders of magnitude faster by common tools, such as bowtie and bwa ,9. Interin vivo, with many proteins genuinely binding the chromatin. However, these two scenarios cannot be disambiguated using current technologies.The EBV genome contains several loci that should be interpreted with caution when using sequencing data. Regions that are seemingly depleted may in fact be regions whose copy number was overestimated  or has orthologous regions in the human genome and, therefore, is unmappable . Furthermore, an initial challenge in any large data study is segregating the data into what is robust, spurious or artifactual. In the case of ChIP, the traditional controls of sonicated genomic DNA (“input”) and non-specific IgG ChIP provide information on two independent background noises. The EBV genome has no regions that appear enriched in the input controls, indicating that the genome is fairly uniform with no genomic regions being more easily sonicated than others. However, the FR repeats are enriched in several IgG ChIP controls, which suggests that FR lacks antibody specificity and is likely to be some form of “sticky” chromatin, possibly due to its potential role as a nuclear matrix attachment region . Even thSince meta-analyzing genomics experiments for EBV comes with the same caveats as analyzing data for human, it is highly recommended that all experiments be first mapped to the human genome. Quality statistics should be generated from the typically millions of mapping reads and thousands of relevant human loci instead of the typically <20 sites in the viral episome. Quality metrics include cross-strand correlation, which is an effective measure for fragment length and enrichment relative to genomic background  and enriExperiment reproducibility should also be examined in both the human and EBV genomes. However, even examining biological replicates across only the EBV genome can generate an estimate of reproducibility. For instance, NF-kB experiments give widely varying peak results. In this case, only the best replicates can be selected from the human aligned data. In some cases, even when an experiment is highly reproducible in human, a low number of reads mapping to the viral episome makes one or multiple replicates unreliable; however, this has mostly ceased being a problem with the advent of deeper sequencers.One complication of analyzing the EBV epigenome through publically available data is that most LCLs are transformed using the B95.8 genome, which contains a large deletion in the Bam HI A region that encompasses the duplicated lytic origin (OriLyt right or DSr) and many BamHI A non-coding RNAs and miRNAs ,12. EvenIn latently infected cells, the EBV genome is chromatinized with density similar to that of the host genome. Nucleosome position and histone tail modifications are strong indicators of chromatin structure and gene regulation. Micrococcal nuclease I (MNase I) and DNase I mapping studies can be used to assess the overall chromatin density and structure of viral genetic loci. For EBV, the majority of the genome is occupied by nucleosomes with varying degrees of static positioning or phasing, consistent with the dynamic nature of the viral genomes in LCL populations . Mapping histone modifications across the EBV genome reveals enrichment of several marks at specific genome positions B. EnrichHistone modifications associated with facultative (H3K27m3) or constitutive (H3K9m3) heterochromatin appear generally low throughout the EBV genome. This may be due to the type III latency program in which most of the latent genome is transcribed. It may also be due to the partial or abortive lytic gene expression observed in some LCLs. In contrast, the latent KSHV genome has several broad peaks of H3K9m3 and bivalent K3K27m3 and H3K4m3 marks at lytic switch regulatory regions . For EBVCTCF is an eleven zinc finger DNA binding protein that has been implicated in chromatin boundary function, enhancer blocking and DNA-loop formation ,22. CTCFEBV gene expression is regulated by mechanisms similar, if not identical, to host cell genes. Therefore, it is not surprising that many cellular transcription factors bind at multiple locations across the EBV genome . TranscrTranscription factor co-occupancy is observed at several key regulatory elements of EBV. The combination of factors at each of these sites may provide interesting new insights into signaling pathways and interactive transcription factor networks. For instance, BATF, JunD, Max and TRF4 are enriched at Cp; OriLyt-L (BHLF1/BHRF1 divergent promoter) contains binding sites for BCL3, ELF1, PBX3, POU2F2, RXRa and cFOS; and the LMP2 promoter binds TCF12, EBF, ZNF143 and JUND. Several cellular factors were found to bind to regions of the viral episome with no known regulatory functions. For example, ATF3, USF1 and USF2 show strong colocalization at ~80,655, which falls within the first internal repeat of the EBNA3A transcript. Another example is SRF and NRSF binding at 112,407, which falls near the putative promoter elements of the capsid protein BGLF3 promoter, a lytic protein not likely to be expressed during latent infection. The colocalization of this particular subset of factors at these genetic regulatory elements suggests a partitioning of factor functions and warrants further investigation.Examination of non-sequence specific transcription co-activators reveals a remarkable enrichment at the OriLyt (L) or OriLyt (R) control elements . In partThe origin of latent replication (OriP) is the episomal maintenance element that can serve as an origin of DNA replication and tethers the viral genome to host metaphase chromosomes during mitosis ,28. As sAs mentioned above, several transcription factors colocalize at OriP. Previous studies have shown that Oct2 (Pou2F2) can bind to FR, and ENCODE ChIP-seq shows strong enrichment of Pou2F2 at FR B. A numbDNA methylation contributes to the balance of limiting gene expression and avoiding immune detection during latency, while establishing a landscape that can be overcome during lytic reactivation to express the >70 gene products involved in replication. The EBV genome packaged in virions is unmethylated and gradually becomes methylated by host factors during initial cellular infection. Genome-wide analysis of methylated CpG levels in the EBV genome has revealed that the origin of plasmid replication OriP, the Cp and the Qp promoters, and the region for the noncoding RNA EBERS lack significant levels of DNA methylation in lymphoblastoid cell lines during latency ,31. InteThrough meta-analysis, it is possible to discover and observe many phenomena; however, just as notable are the phenomena that are not observed. While negative results are typically not formally reported, they can be accrued in unbiased databases of experiments mapped to the viral genome . For insPreviously identified regulatory interactions are largely confirmed in high throughput analyses. However, a small subset of experiments yielded surprising negative results. For instance, NF-kB binding at LMP1p was either weak or non-existent. Additionally, ZEB1 binding to Zp could not be confirmed. In both of these examples, it was crucial that positive controls in the viral and host genomes were provided. Importantly, the ChIP-seq methods are only semi-quantitative, and observed peaks of significant interest need to be validated by conventional ChIP and qPCR methods, which have been performed at only a small subset of these sites.The EBV epigenome, as revealed by data mining, reflects only a small fraction of the protein interactions and histone modifications that define the viral chromosome. It is certainly not a complete nor comprehensive characterization of the proteins and modifications that regulate the EBV genome in all its dynamic complexity. Nevertheless, the insights gained from this “tip of the iceberg” glimpse of the EBV epigenome suggest that this discovery approach can reveal many new and previously unanticipated regulatory features of viral-host interactions, gene regulation and chromosome organization. Many of the observations discussed in this review need to be experimentally validated and further characterized to fully assess their functional significance. However, these observations indicate that “omics” dissection of viral and host gene regulation can generate new concepts and hypotheses and a deeper understanding of how the viral and cellular genomes persist during latent infection.


Coronary artery disease (CAD) is a leading cause of death and disability worldwide. In addition to lifestyle and environmental factors which are major aetiologic determinants, there is considerable familial clustering of the disease indicating a genetic component in its causation. Although the total genetic contribution to CAD risk can be quantified, the determination of the size and number of contributing effects is impossible without identifying all CAD susceptibility genes. However, despite extensive studies, strong evidence of a molecular genetic association with coronary artery disease or myocardial infarction remains elusive. Genome wide association studies have been successful in identifying robust associations of single nucleotide polymorphisms (SNP) with CAD. Identifying the causal variant and dissecting pathways linking these variants to disease process is a major challenge. Technologies from whole genome sequencing, proteomics, transcriptomics and metabolomics are now available to extend analysis to a more complete range of potential susceptibility variants, and to support more explicit modelling of the joint effects of genes and environment. The availability of these high throughput technologies does not diminish the importance of rigorous phenotyping and appropriate study designs in all the endeavours to understand the aetiopathogenesis of CAD. Combining classical epidemiology with modern genomics will require collaborative efforts within the cardiovascular disease community at both bench and bedside and this will have the potential to expand our understanding of CAD and translate discoveries into clinically useful applications that will have a major impact on public health. Coronary arery disease (CAD) is predicted to be the most common cause of death globally, including India, by 2020, when the 10 leading causes of disability-adjusted life-years (in descending order) are projected to be ischaemic heart disease, unipolar major depression, road traffic accidents, cerebrovascular disease, chronic obstructive pulmonary disease, lower respiratory infections, tuberculosis, war injuries, diarrhoeal diseases, and HIV11e.g. angina, myocardial infarction (MI)] which are caused by atherosclerosis, a pervasive degenerative condition in which lipid and fibrous matrix is deposited in arterial vessel walls to form atheromatous plaques. Rupture of unstable plaques in coronary arteries results in the release of thrombogenic material into the lumen of the vessel leading to coronary thrombosis, vessel occlusion, and subsequent infarction of the myocardium, a critical condition with high mortalityCAD comprises a spectrum of clinical diagnoses 17etc. It is likely that susceptibility genes might be involved in novel biological pathways or be novel genes in well known pathways such as cholesterol metabolism. The search and identification of genetic factors contributing to CAD is important to increase our understanding of CAD pathophysiology and develop new strategies for risk prediction and intervention.All these point to a multifactorial polygenic causation of CAD, with evidence that susceptibility genes for CAD might exist that are independent of hypercholesterolaemia or arterial hypertension or diabetes and may act by affecting an intermediate factor such as vascular inflammation, oxidative stress, thrombogenicity, arterial calcification, ABCA1, APOA1, LCAT) that influence HDL levels, were jointly found to make a substantial contribution to the population distribution of HDL levels25The success of CAD gene mapping is dependent on its genetic architecture which refers to the number of disease genes that exist, their allele frequencies, the risks that they confer, and the interactions between multiple genetic and environmental factors1923The common methods used in the genetic dissection of complex diseases like CAD are linkage and association studies. Linkage mapping , which is a powerful tool for finding Mendelian disease genes, often produces weak, and sometimes inconsistent, signals in complex disease studiesAscertainment criteria partitioning the presence or absence of CAD are a major challenge and have major implications on the power and success of gene mapping studies. Studies of asymptomatic individuals have shown that atherosclerotic CAD is pervasive, but only a fraction of them will ever develop an MI, and this is influenced by haemodynamic modifiers or individual susceptibility to inflammation and plaque progression29Many of the known risk factors for the development of CAD are genetically determined traits - LDL and HDL levels, high blood pressure, type 2 diabetes and metabolic syndrome. A growing number of other plasma factors have also been identified that are associated with CAD risk, many of which are also strongly genetically determined The selection of cases or ‘affected’ takes into consideration not only phenotypic definition to reduce phenotypic heterogeneity, but also manoeuvres to improve study power through enrichment of specific disease-predisposing alleles. There is an argument for using related cases, as they are more likely to share a disease-causing variant in common than randomly selected cases, provided the data are analyzed after taking into account correlation between related individuals32There are important factors to be considered when selecting a CAD phenotype for studyThe definition of controls or ‘unaffected’ is more challenging than cases34From a practical point of view, it would be ideal to identify controls without having to subject individuals to an invasive assessment. However, stress testing, even with adjunctive nuclear or echocardiographic imaging is not sensitive. Currently the gold standard technique is an invasive diagnostic angiogram which is expensive and carries a definite albeit low risk of morbidity and death. The definition of a normal angiogram is still unclear, and the appearance of a truly “normal” angiogram is not particularly common as compared with finding individuals who have minor irregularities with no frank luminal encroachment that would approximate a 10 per cent narrowingUsing a positional cloning approach, linkage analysis using families of multiple affected individuals was very successful in identifying genes for Mendelian diseases. However, it has been less successful in identifying genes for complex diseases. Recently genome wide association studies which have been successful in identifying replicated loci for common diseases have predominantly used a case-control approach, where samples of unrelated affected and unaffected individuals are ascertained from the study population. While it is extremely easy to recruit unrelated cases and control, recruitment of families is resource intensive. But it must be recognised that population and family studies have different strengths and weaknesses and must be viewed as complementary and not competitive35A key concern with case-control design is latent population substructure that will inflate type I error and care must be taken when attempting to reproduce these results in other populations. Though there are statistical methods to correct for population substructure along with information from ancestry informative markers, these are only applicable to populations of European ancestry, these will correct only for ‘average’ genome wide measures of ethnic admixture and will not always eliminate spurious associations immediately adjacent to markers that are strongly informative about ancestry352435The key advantage of family studies is that they are robust to population stratification36The successful detection of gene-gene or gene-environment interactions is dependent on recruiting adequate sample sizes in the prospective cohort studies. In contrast to case-control studies which typically begin when disease cases have occurred, prospective cohort studies avoid this inherent bias by investigating a representative sample of the population before disease onset. In terms of genetic main effects, 5000 incident cases are needed for a minimum detectable odds ratio (MDOR) of 1.5 with 80 per cent power and MAF=5 per cent. For genotypic and environmental prevalences of 10 per cent and above, 10,000 cases are needed to provide adequate power for interaction effects with an MDOR greater than 2354646-6 indicating a gene that is in linkage disequilibrium (LD) near or even within the microsatellite region. However, identifying disease causing genes interspersed within microsatellites has proved to be quite difficult and studies from different centres reported varying results - Finland (2q21.2-22 and Xq23-26)52ALOX5AP and MEF2A, have been identified by fine mapping studies following the original linkage analysis. The Icelandic locus was replicated in population-based studies from Iceland and England, with different haplotypes of the ALOX5AP gene (encoding 5-lipoxygenase activating protein) associated with CAD in the two countries, and the Icelandic haplotype was also associated with stroke in Iceland and in Scotland50Previous methods for determining genetic linkage of a complex disease relied chiefly upon the technique of genome wide scanning of microsatellites (short tandem repeat sequences). This required the laborious selection of hundreds of families, particularly sib pairs with MI or CAD. Using around 400 microsatellite markers distributed evenly across the genome, the goal was to identify a significant linkage peak defined by a logarithm of odds ratio (LOD) greater than 3.5 corresponding to a p<10Candidate gene association studies often base selection of candidate genes on assumptions about biologically relevant genes, and hence these studies are biased against identification of novel genes. An overlap in inflammatory responses observed in chronic infection and atherosclerosis led to an interest in candidate genes for CAD that are involved in innate immunityIn a pioneering studya priori likelihood of identifying the important variants. However, as small scale studies are easy to carry out these have become numerous; some, by chance, yield a false positive association and there is evidence of publication bias in the literature that might enrich for false positives.Despite some successes, single gene association studies remain problematic, with most being poorly replicable23Of the 3.1 billion base pairs in our genome, our inter-individuality is determined by only 0.1 per cent or approximately 3 million of those base pairs. GWA studies are large scale association mapping using SNPs, making no assumptions of the genomic location or function of the causal variant and are a comprehensive approach to testing the hypothesis that common alleles contribute to heritable phenotype variation24CDKN2A and CDKN2B. Thus a large number of SNPs in this region show highly significant association with CAD and the causally responsible variant and the related mechanism remains to be identified. The CDKN2A and CDKN2B genes are cyclin-dependent kinase inhibitors which regulate cell cycle and belong to a family of genes that have been implicated in the pathogenesis of atherosclerosis through their role in transforming growth factor-β-induced growth inhibition. However, the most strongly associated SNPs lie considerably upstream of these genes, and the nearest signal is 10 kb upstream of CDKN2B. The C-allele of the lead SNP (rs1333049) has a frequency of 0.17 in Yoruba, 0.48 in Han Chinese, 0.51 in Japanese and 0.49 in Europeans indicating that the risk of CAD and MI related to the chromosome 9p21 locus may vary among different ethnic groups. More interestingly, this same susceptibility locus was found to be independently associated with type 2 diabetes69PSRC1), melanoma inhibitory activity family, member 3 (MIA3) and mothers against decapentaplegic homolog 3 also known as SMAD family member 3 (SMAD3) encoding cell-growth regulators, and a locus near the gene encoding the chemokine (C-X-C motif) ligand 12 (CXCL12)The association of 9p21 locus with CAD and MI has been found in every GWA studies published including a meta-analysis which suggests, at least, that this association is widely distributed66CETP), lipoprotein lipase and hepatic lipase]. In addition, a SNP in the gene glucokinase (hexokinase 4) regulator (GCKR), which encodes glucokinase regulatory protein, was found to have a highly significant association with triglyceride concentrationsMVK-MMAB) and UDP acetylgalactosaminyltransferase 2 (GALNT2), with high-density lipoprotein (HDL) cholesterol; near sortilin 1 (SORT1), cadherin EGF LAG seven-pass G-type receptor 2 (CELSR2) and Proline/serine-rich coiled-coil protein 1 (PSRC1) with variants primarily associated with low-density lipoprotein (LDL) cholesterol; near Tribbles homolog 1 (TRIB1), MLX interacting protein-like1 (MLXIPL) and angiopoietin-like 3 (ANGPTL3), with variants primarily associated with triglycerides; and a locus encompassing several genes near neurocan (NCAN), with variants strongly associated with both triglycerides and LDL cholesterol74There is also evidence of strong signals for intermediate phenotypes from GWA studies. The Diabetes Genetics Initiative was designed to investigate type 2 diabetes, but 18 other phenotypes, including plasma lipid concentrations, were analysed as secondary traitsFor most phenotypes, genes that were previously identified by linkage analysis, however, have not been found to be associated using GWA studies. There are several explanations for this- the particular chip configuration used covered these genes poorly and so the genetic effect was missed; the quantitative contribution of the genes to the disease is lower when ranked compared with other genes; or the association was missed because it was not present to a great degree in a particular study sample3542Validating new discoveries related to atherosclerosis will require multiple complementary approaches.PCSK9 gene were associated with lower LDL cholesterol and protection from CVD, single gene mutations in sarcomere genes were associated with a small but significant proportion of men and women with left ventricular hypertrophy (LVH)76The GWA approach has been extremely successful in identifying common SNP variants with modest effect on the CAD phenotype. However, this does not detect whether rarer variants play a role in CAD and it is unable to explain all of the observed familial clustering. All these emphasize the need to extend analysis to a more complete range of potential susceptibility variants, and to support more explicit modelling of the joint effects of genes and environmentet alet alThe SNP association studies cannot determine which SNPs may affect gene expression or function. Gene expression microarray technology provides a way to scan rapidly specific tissues for patterns of expression among thousands of genes across the genome and provides both qualitative (switched on/off genes) and quantitative data , so that subtle differences of gene activation can be detectedThere are approximately ten times more proteins than genes, and expression arrays should preferably be complemented by proteomic evaluation as they cannot assess potentially important post-transcriptional variables including alternative splicing of mRNA, control subjects on protein translation, and post-translational processing of proteins82The study of the collection of small molecular-weight organic and inorganic species present in a biological system is defined as metabolomics, and provides a phenotypic profile either as a snapshot in time or as an integrated picture of biology over a period of time. Metabolites are the final downstream product of gene transcription and so reflect more closely the phenotype at a functional level, and the metabolome is thought to be a potentially more sensitive marker of cellular processes both in normal physiology and disease.et alP<0.0001). Analysing 4,630 participants from the INTERMAP epidemiological study, involving 17 population samples aged 40-59 in China, Japan, UK and USA, Holmes et alP<10-16) and mean 24-hour urinary excretion of alanine (direct) and hippurate (inverse), reflecting diet and gut microbial activities, were also associated with blood pressure of these individuals.As proof of principle, Sabatine Thus metabolomic analysis may not only identify potential biomarkers for CV disease but may also provide information regarding prognosis, response to therapy, and underlying mechanisms of the disease.Rapid advances in genomic, proteomic, and metabolomic technology provide researchers with valuable tools for understanding the genetic predisposition to atherosclerotic cardiovascular disease and have led to the development of successful therapeutic interventions for atherosclerotic cardiovascular disease; for example, reducing plasma concentrations of atherogenic lipoproteins (with statins) and blocking rennin-angiotensin-aldosterone system activity (with ACE inhibitors and angiotensin-receptor blockers). Combining classical epidemiology with modern genomics will require collaborative efforts within the cardiovascular disease community at both bench and bedside, and is likely to pay major dividends with the development of a new generation of personalised prevention and treatment interventions that will have a major impact on public health.


Many Studies suggest that changes in sympathetic nerve activity in the central nervous system might have a crucial role in blood pressure control. The present paper discusses evidence in support of the concept that the brain renin-angiotensin system (RAS) might be linked to sympathetic nerve activity in hypertension. The amount of neurotransmitter release from sympathetic nerve endings can be regulated by presynaptic receptors located on nerve terminals. It has been proposed that alterations in sympathetic nervous activity in the central nervous system of hypertension might be partially due to abnormalities in presynaptic modulation of neurotransmitter release. Recent evidence indicates that all components of the RAS have been identified in the brain. It has been proposed that the brain RAS may actively participate in the modulation of neurotransmitter release and influence the central sympathetic outflow to the periphery. This paper summarizes the results of studies to evaluate the possible relationship between the brain RAS and sympathetic neurotransmitter release in the central nervous system of hypertension. There is increasing evidence to suggest that sympathetic nervous activity in both central and peripheral nervous systems may play a major role in the regulation of blood pressure, and that hypertension is accompanied characteristically by increased sympathetic nervous activity in both humans and animal models , 2. Phar2+-mobilization was reduced in A2 neurons of SHR. Because A2 neurons are a part of an antihypertensive circuit, the reduced sensitivity of the A2 cells to Ang II might further compromise their homeostatic role in SHR. There might be regional differences in the amount of NE release in the central nervous system of hypertensive models. Augmented norepinephrine (NE) release and catecholamine synthesis as well as tyrosine hydroxylase gene expression have been reported at central sites related to blood pressure regulation in adult spontaneously hypertensive rats (SHR) , 13. In In human hypertensive subjects, Esler et al.  studied It was shown that angiotensin I (Ang I) and Ang II injected to the central nervous system significantly elevated blood pressure . Davern 1) receptors are quite different from the angiotensin type 2 (AT2) sites and that these receptors may exert opposite effects on blood pressure regulation [1 receptors might have a pivotal role in NE neuromodulation, and that evoked NE neuromodulation might involve AT1 receptor-mediated, losartan-dependent, rapid NE release, inhibition of potassium-channels and stimulation of Ca2+-channels. Furthermore, they proposed that AT1 receptor-mediated enhanced neuromodulation might involve the Ras-Raf-MAP kinase cascade and lead to an increase in NE transporter, tyrosine hydroxylase, and dopamine β-hydroxylase mRNA transcription. On the other hand, neuronal AT2 receptors might signal via a Gi-protein and be coupled to activation of PP2A and PLA2, and stimulation of potassium-channels. Nap et al. [1 receptors might belong to the AT1B receptor subtype because AT1B receptor inhibition by high concentrations of PD 123319 could suppress the Ang II-augmented noradrenergic transmission. Gironacci et al. [2 receptors. In addition, they showed that the inhibitory effect of Ang-(1-7) on NE release was blocked by the nitric oxide (NO) synthase inhibitor and the bradykinin (BK) B2 receptor antagonist. The finding indicated that Ang-(1-7) reduced NE release from the hypothalamus of SHR via the AT2 receptors, acting through a BK/NO-mediated mechanism. Recent findings have also revealed that the Mas oncogene may act as a receptor for Ang-(1-7) [1 receptor axis [Several lines of evidence demonstrate that function and signaling of the angiotensin type 1  –44. It itor axis –44. 1 receptor binding in both RVLM and caudal ventrolateral medulla as well as dorsomedial medulla was increased in SHR compared with normotensive rats. Conversely, expression of the novel, non-AT1, non-AT2, Ang II and III binding site, which was recently discovered, might be decreased in the RVLM and dorsomedial medulla of SHR [1 receptor binding in the RVLM might contribute to the hypertension of SHR, whereas reduced radioligand binding to the novel, non-AT1, non-AT2, angiotensin binding site in the RVLM of SHR might indicate a role for this binding site to reduce blood pressure via its interactions with Ang II and III. Bourassa et al.  demonstra of SHR . They prIn this context, the facilitative effect of Ang II on NE release might be an important factor in the excitation of sympathetic tone in the central nervous system, although further studies should be performed to assess more thoroughly the precise roles of the different types of Ang II receptors in the regulation of central sympathetic nerve activity in hypertension. All components of the RAS have been identified in the brain, and the brain RAS might actively participate not only in blood pressure elevation, but also in target organ damages –9, 46. IThe different structures of ACEIs may influence their tissue distribution and routes of elimination. Cushman et al.  examinedIn an in vitro study presented previously, we showed that captopril significantly inhibited the stimulation-evoked NE release in slices of rat hypothalamus and medulla oblongata , as well1 receptor blocker prevented sympathetic hyperactivity and hypertension in Dahl salt-sensitive hypertensive rats on high salt diet. It was shown that Ang II administered intracerebroventricularly at a dose that induces drinking behavior in rats significantly increased potassium-stimulated release of NE in the hypothalamus . It can 1 receptor blocker candesartan suppressed the central responses of Ang II in a dose- and time-dependent manner in conscious rats, indicating that the AT1 receptor blocker might effectively inhibit the centrally mediated action of Ang II upon peripheral application. It was also shown that peripherally administered candesartan markedly decreased AT1 binding areas outside  and inside  the blood-brain barrier [Previous studies have reported only a limited ability of systemic ARB to cross the blood brain barrier –69. Gohl barrier , 67. Ung barrier  proposed1 receptors appears to differ markedly between the individual agents in this drug class. Recently, Krum et al. [ In human hypertensive subjects, Esler  proposedm et al.  examinedOn the other hand, de Champlain et al.  showed tRecent years have seen the development of the nonpeptide, orally long-term effective direct renin inhibitor (DRI), aliskiren, which may block the initial stages of the RAS and exert a sustained antihypertensive action in hypertensive subjects –76. With regard to the influences of aliskiren on central sympathetic nervous system, Huang et al.  examined In a clinical study, it was shown that aliskiren significantly reduced sympathetic hyperactivity and blood pressure in patients with chronic kidney disease (CKD) . However1 receptors. It is proposed that PRR blockade in the central nervous system might represent a novel approach for the treatment of neurogenic hypertension. Recent evidence indicates that the (pro)renin receptor (PRR), which is a newly discovered member of the brain RAS, might contribute to the pathogenesis of hypertension –82. Li eIt has been shown that aldosterone as well as Ang II might act within the central nervous system and cause the sympathetic hyperactivity to increase blood pressure –87. Huan1 receptors might activate the NADPH oxidase complex which could be the most important source of reactive oxygen species (ROS) and suggested that the produced superoxide anion would be converted into H2O2 by superoxide dismutase or combine with NO to generate peroxynitrite, thereby decreasing NO-bioavailability and promoting lipid and protein oxidation. Additional studies are necessary in order to further unravel the implications of oxidative stress in the Ang II-induced neurotoxicity in the brain. The involvement of oxidative stress is implicated in the pathogenesis of hypertension. It was demonstrated that superoxide anions in the RVLM, which might generate hydroxyl radicals, were increased in SHR-SP (stroke prone), suggesting that increased oxidative stress would lead to enhancing the central sympathetic outflow , 91. RecThere is increasing evidence to suggest that dopaminergic nerve activity in the central nervous system may play a crucial role in the regulation of blood pressure –102. Rec1 receptor antagonist, losartan, but not by the AT2 receptor antagonist, PD 123177, suggesting that Ang II acting via the AT1 receptor subtype might facilitate the release of dopamine, in the rat striatum. By using the microdialysis method, Mendelsohn et al. [It has been demonstrated that ACE is localized throughout the brain and, importantly, is found in neurons of striatum and nigrostriatal tract . In addin et al.  showed tOn the other hand, it has been proposed that the nigrostriatal dopaminergic system may mediate baroreflex sensitivity in rats because both striatal dopamine release and baroreflex responses produced by phenylephrine and carotid occlusion were attenuated by lesions of the nigrostriatal dopaminergic pathway . It has 1 receptors have been identified on dopamine containing cells in the substantia nigra and striatum of human brain using receptor autoradiography. Mertens et al. [1 and AT2 receptors might exert an opposite effect on the modulation of DA synthesis in the striatum. Speth and Karamyan [1, non-AT2 binding site for angiotensin peptides as a mediator of nontraditional actions of Ang II, could have a role in the stimulation of dopamine release from the striatum.Jenkins et al.  observeds et al.  showed tKaramyan  demonstr1 receptors might play a pivotal role in Parkinson's disease. As mentioned above, the stimulation of AT1 receptors might lead to the activation of the NADPH oxidase complex and the generation of ROS [2 receptor agonists alone or in combination with AT1 receptor blockers might effectively improve the pathological conditions in Parkinson's disease. It was also shown that chronic treatment of ACEI increased striatal dopamine content in the MPTP-mouse [ Several studies have been made to elucidate the possible link between the brain RAS and the dopaminergic cell death in Parkinson's disease , 113. Onn of ROS , 93. MerTP-mouse . On the In this context, it can be speculated that the striatal dopaminergic system may actively participate in the control of blood pressure and behavioral responses, although further studies should be performed to assess the precise role of the RAS in the regulation of central dopaminergic nerve activity and its modulation by the RAS inhibitors.Previous studies have shown that the central cholinergic system may also actively participate in blood pressure control –123. Buc1 receptors might be involved in the scopolamine-induced amnesia and that AT2 receptors could contribute to the beneficial effects of the RAS inhibitors. The findings might propose the idea that inhibition of the brain RAS in hypertensive subjects would be neuroprotective against Alzheimer's disease, although further studies are necessary to assess more thoroughly the relationships between the RAS and central cholinergic nerve activity and their roles in the regulation of blood pressure and neurological functions.  Recently, the possible link between the brain RAS and the pathophysiology of Alzheimer's disease has been documented. Tota et al. , 125 obs1 receptors and vasopressin levels in the renin-angiotensinogen double-transgenic hypertensive mice [Brain RAS also modulates the cardiovascular and fluid-electrolyte homeostasis by interacting hypothalamic-pituitary axis and vasopressin release , 127. Itive mice , suggest1 receptor blocker, ZD7155, into the RVLM significantly decreased glutamate and increased GABA levels [2 receptor blocker, PD 123319, increased glutamate and decreased GABA levels within the RVLM [1 receptor signaling. These findings suggested that the RAS might have a crucial role in the regulation of cardiovascular and neurological functions by modulating glutamate/GABA release in the brain.The role of the brain RAS on glutamate/GABA neurotransmission has also been described –132. It A levels . In contthe RVLM . Fujita All components of the RAS have been identified in the central nervous system, and the brain RAS may regulate blood pressure by modulating sympathetic nerve activity. It has been proposed that the RAS may have a stimulatory influence on the sympathetic nervous system. The brain RAS may augment presynaptic facilitation of sympathetic neurotransmitter release and enhance the central sympathetic outflow. In the present paper we discussed the relationship between the brain RAS and sympathetic neurotransmitter release in hypertension . Ang II Clearly, more studies are required to further evaluate the precise role of the brain RAS in the control of sympathetic nerve activity, blood pressure, and neurological functions. In addition, better knowledge of the cellular mechanisms in the brain RAS could provide useful information concerning the development of a more specific and more physiological approach to hypertensive research.


Cells in aerobic condition are constantly exposed to reactive oxygen species (ROS), which may induce damage to biomolecules, including proteins, nucleic acids and lipids. In normal circumstances, the amount of ROS is counterbalanced by cellular antioxidant defence, with its main components—antioxidant enzymes, DNA repair and small molecular weight antioxidants. An imbalance between the production and neutralization of ROS by antioxidant defence is associated with oxidative stress, which plays an important role in the pathogenesis of many age-related and degenerative diseases, including age-related macular degeneration (AMD), affecting the macula—the central part of the retina. The retina is especially prone to oxidative stress due to high oxygen pressure and exposure to UV and blue light promoting ROS generation. Because oxidative stress has an established role in AMD pathogenesis, proper functioning of antioxidant defence may be crucial for the occurrence and progression of this disease. Antioxidant enzymes play a major role in ROS scavenging and changes of their expression or/and activity are reported to be associated with AMD. Therefore, the enzymes in the retina along with their genes may constitute a perspective target in AMD prevention and therapy. Age-related macular degeneration (AMD) is a progressive disease of the central part of the retina, which may lead to a partial or complete vision loss in one or both eyes among people aged 55 years and older in developed countries. The disease may be accompanied by the reduction of the visual acuity, however, the absence of visual impairment does not exclude AMD  is a physiological process. Provided that radicals are effectively scavenged by the cellular antioxidant defence systems, their presence is not detrimental. The imbalance between oxidants and antioxidants in favour of the oxidants, results in oxidative stress. This is a pathogenic condition leading to damage of numerous cellular components including lipids, proteins and nucleic acids. A concept formulated by Denhama Harman states that aging is a result of ROS-induced damage accumulation Harman . ExperimThe retina is a tissue abundant in ROS Fig. . First, 2+ and augmented mitochondrial Ca2+ sequestration. Knockdown of MnSOD , an antioxidant mitochondrial enzyme, stimulated a long-term mitochondrial oxidative stress, which evoked the increase in superoxide anion, apoptotic cell death, degeneration of RPE cells, thickening of Bruch’s membrane, shortening and disorganisation of the photoreceptor outer and inner segments , cell apoptosis and DNA oxidation  penetrates the eye reaching the retina, where it may induce damage to retinal cells  (22:6 ω3), exclusively of dietary origin. Since the susceptibility of unsaturated fatty acids to oxidation increases with the number of double bonds, the photoreceptors are particularly vulnerable to lipid peroxidation Witting . This prPhotosensitizes are chemical compounds that absorb light and subsequently emit radiation, which may induce chemical reactions contributing to cell photochemical damage Fig. . There aThe degree of retinal degeneration positively correlated with the rhodopsin content in the retina before light exposure (Rapp and Williams 2O2) under aerobic conditions. This photoinducible generation of radicals was shown to result in lipid peroxidation, partial or complete inactivation of antioxidant enzymes, including SOD and catalase, in RPE cells and RPE cellular dysfunction  showed that the consumption of fruit and vegetables, being a source of antioxidants, negatively correlated with the occurrence of AMD , oxidised state of GSH, in whole blood increased with age  is an antioxidant and participates in H2O2, as well as the adjacent RPE cells or photoreceptors without up-regulated catalase expression  the miRNA expression pattern differs between AMD patients and individuals without this disease  stress in the retinal degeneration accompanied by oxidative stress and death of photoreceptors H quinine oxidoreductase 1 (NQO1), glutathione S-transferases (GST) and glutamate-cysteine ligase (GCL)  via the transcription factor Nrf2 (NF-E2-related factor 2)  in the pathogenesis of this disease  was associated with the exudative form of AMD in Japanese population , CAT  and Gpx1  genes conducted on a Northern Irish population showed no significant association with AMD (Esfandiary et al. There is a growing body of evidence that oxidative stress may contribute to the initiation and progression of AMD. It is believed that the degeneration of RPE cells is an early event in the pathogenic process leading to AMD. Certain factors affecting RPE cells may render them especially susceptible to oxidative damage. These factors include deficiency in low molecular weight antioxidants, DNA repair and antioxidant enzymes Fig. . In the Antioxidant supplementation has provided promising results slowing down AMD progression and preventing AMD occurrence indicating its clinical potential. The AREDS study demonstrated that daily oral supplementation with antioxidant vitamins and minerals reduced the risk of developing advanced AMD by 25 % after 5 years (Age-Related Eye Disease Study Research Group AMD is a complex, degenerative and progressive eye disease that usually does not lead to complete blindness but can result in severe loss of central vision. All AMD risk factors such as age, genetics, diet, smoking, oxidative stress and many cardiovascular associated risk factors involve increased ROS production. Therefore, effective ROS scavenging may be essential for preventing AMD. Initial successes with diet supplementation with small molecular weight antioxidants in the AREDS study prompt for considering other elements of antioxidant defence as possible targets in AMD prevention and future therapy. The activity of antioxidant enzymes, the main component of antioxidant defence, depends on the sequence of their genes and their epigenetic profile. Therefore, determination of the genotype of these genes in individuals at AMD risk, may have diagnostic and prognostic significance. Also drugs modifying epigenetic pattern of these genes may be considered in AMD prevention. Such kind of drugs were approved for treatment of some cancers. Manipulating in the sequence of these genes by gene therapy may be considered in extreme cases to prevent progression of AMD, but it seems unlikely that this might reverse pathological changes associated with the disease.


With rabies emerging as a particular threat to wild canids, we report on a rabies outbreak in a subpopulation of endangered Ethiopian wolves in the Bale Mountains, Ethiopia, in 2003 and 2004. Parenteral vaccination of wolves was used to manage the outbreak. Highly pathogenic infectious agents have been implicated in the decline and extirpation of a considerable number of populations (Canis simensis)  . The Ethimensis) , althougWolf packs in the Bale Mountains are monitored by the Ethiopian Wolf Conservation Programme staff on foot or horseback, using binoculars, global positioning systems, and, following the rabies control intervention strategy, radio telemetry. Over the last year, the Ethiopian Wolf Conservation Programme monitored 47 packs containing 250–300 wolves, in seven areas in these mountains. During a 6-week period from mid-August to the end of September, the carcasses of four wolves were found in the Web Valley; 15 more dead wolves were found in the first half of October . ThroughCrocuta crocuta) in 1987 but, in general, belongs to the overall group associated with domestic dogs in different regions throughout northern and central Africa (Rabies virus was diagnosed from 13 of 15 brain samples sent to the Centers for Disease Control and Prevention (CDC), USA. The negative samples most likely represent poor-quality samples, but these results are also consistent with background mortality. Diagnostics, RNA extraction from wolf brains, reverse transcription–polymerase chain reaction, N gene sequence generation, and phylogenetic analysis were performed as described in Kuzmin et al.  and limi,At least one previous rabies epidemic has occurred in the Bale Mountains: 77% of 53 known wolves died or disappeared in the Web Valley from 1991 to 1992 , from Apr,All available evidence suggests that domestic dogs are the reservoir for rabies both in the Bale Mountains and Ethiopia; the genetic analysis identified the virus to be of canid type and no wildlife reservoir has ever been identified in this country. Rabies is endemic in Ethiopia and remains both a public health and economic problem through livestock losses in these impoverished rural communities  and Morebawa (n = 36), outside of the core rabies-affected area. Wolves were injected intramuscularly with alternate 1-mL or 2-mL doses of inactivated rabies vaccine . A subsample of 19 wolves was recaptured 30 days later (±5 days) to determine the extent of antibody response to vaccination and to administer a booster dose of 1 mL of vaccine. Preliminary results have shown that all these 19 wolves seroconverted after vaccination. All but one vaccinated wolf were confirmed alive 1 week after vaccination, and all but two wolves were alive 2 months later; both figures are consistent with background death rates. A full analysis of this ongoing work will be reported when data are complete.,This outbreak has highlighted that rabies is a continued threat to endangered canids and that conservationists are often ill-equipped to manage infectious disease. First, lack of information often hinders management: few established models offer guidance. Indeed, some early and unsurprising failures have attracted damaging controversy (


Radiation therapy plays an important role in the management of a wide range of cancers. Besides innovations in the physical application of radiation dose, radiation therapy is likely to benefit from novel approaches exploiting differences in radiation response between normal and tumor cells. While ionizing radiation induces a variety of DNA lesions, including base damages and single-strand breaks, the DNA double-strand break (DSB) is widely considered as the lesion responsible not only for the aimed cell killing of tumor cells, but also for the general genomic instability that leads to the development of secondary cancers among normal cells. Homologous recombination repair (HRR), non-homologous end-joining (NHEJ), and alternative NHEJ, operating as a backup, are the major pathways utilized by cells for the processing of DSBs. Therefore, their function represents a major mechanism of radiation resistance in tumor cells. HRR is also required to overcome replication stress – a potent contributor to genomic instability that fuels cancer development. HRR and alternative NHEJ show strong cell-cycle dependency and are likely to benefit from radiation therapy mediated redistribution of tumor cells throughout the cell-cycle. Moreover, the synthetic lethality phenotype documented between HRR deficiency and PARP inhibition has opened new avenues for targeted therapies. These observations make HRR a particularly intriguing target for treatments aiming to improve the efficacy of radiation therapy. Here, we briefly describe the major pathways of DSB repair and review their possible contribution to cancer cell radioresistance. Finally, we discuss promising alternatives for targeting DSB repair to improve radiation therapy and cancer treatment. During the past few decades extensive efforts have been made to improve cancer therapy both by establishing more successful treatment approaches, as well as by developing effective means for early diagnosis. Despite advances in many fronts, radiation remains one of the most successful treatment modalities for solid cancers that is applied to over 50% of all cancers at one stage of their management , induces a plethora of DNA lesions, including oxidative base damages, single-strand breaks (SSBs), and double-strand breaks (DSBs), which affect the DNA integrity or alter its chemical nature Ward, . Among tHowever, while treating tumors, radiation also always reaches normal tissue risking the development of side effects and the generation of secondary malignancies. As a result, the central challenge of radiation therapy is to maximize tumor cell killing and minimize at the same time the normal tissue side effects. Modern conformal, intensity-modulated radiation therapy approximates this goal by optimizing radiation dose deposition between tumor and the surrounding normal tissue. Further improvements are possible using biological approaches that exploit differences in radiation response between normal and tumor cells and aim at protecting normal cells while maximizing the radiation response of tumor cells. Thus, radiosensitizing agents offer a benefit when radiosensitization occurs rather specifically in cancer cells.The observation that components of the homologous recombination repair (HRR) pathway are aberrantly expressed in many tumors , which can be subdivided in DNA-PKcs dependent NHEJ (D-NHEJ) and alternative/backup NHEJ (B-NHEJ) (see below), and HRR.D-NHEJ catalyzes a simple rejoining reaction between two DNA ends irrespective of their origin Lieber,  and does−9 M, depending on the DNA end-structures), makes it the ultimate initiation factor of this repair pathway  is required to generate ligatable ends  and the X-ray cross complementing 4 (XRCC4) protein (LIG4/XRCC4) Figure . AssisteDuring the past decade a second pathway for rejoining of broken DNA molecules on the basis of NHEJ was discovered and is presently intensively investigated. As with D-NHEJ this repair pathway also lacks means to restore sequence information at the DSB, and as we will discuss later, it also has a higher probability to join unrelated DNA ends.Initially, analyses of DSB repair using pulse-field gel electrophoresis (PFGE) in cells deficient in components of D-NHEJ, revealed a robust repair activity that was unrelated to HRR (see below) and reflected a different form of DNA end-joining instead  polymerase 1 (PARP-1), which plays a main role in the repair of SSBs (see below) and which may effectively compete with KU heterodimer for DNA end-binding . Notably, B-NHEJ is severely compromised when D-NHEJ deficient cells enter a plateau phase of growth or are deprived of serum , a versatile ligase, which in complex with XRCC1 also participates in the repair of SSBs and DNA base damages , together with LIG3, was found upregulated in chronic myelogenous leukemia (CML), where several D-NHEJ activities are suppressed. Under these conditions WRN and LIG3 form a stable complex, which is recruited to DSBs, thus activating the ligation process  Figure . RPA is The exact function of the RAD51 paralogs remains elusive, but there is evidence that they may form distinct complexes, which facilitate the formation and stabilization of the RAD51 filament . When homology is found (synapsis) DNA synthesis will start elongating the 3′-end of the invading strand Figure . For eloFirst reported in yeast and later in higher eukaryotes, recombination events between areas of homology present in the same DNA molecule could be observed. This process is known as SSA  – has been described, that steps into action when one sided DSBs are formed. It is characterized by the initiation of replication through the formation of a replication fork that replicates the entire chromosome past the DSB , BRCA2, BLM, and CtIP are all regulated throughout the cell-cycle  protein kinase, which plays an important role during DSB repair by homologous recombination  (in a CHK1/2 independent manner) collaborate to dissociate a p53/RPA-complex by phosphorylating both of its components  that are elicited by DNA damage or replication stress. We will focus on a small selection of PTMs of proteins that either play a central role in HRR, or exert regulatory functions at key HRR steps.As mentioned above, CtIP is critical in the regulation of end-resection and is itself post-translationally modified in several ways. Also EXO1, one of the major nucleases implicated in DNA end-resection, has been shown to be phosphorylated at multiple sites. Phosphorylation of EXO1 at Ser-714 by ATM, for example, is required for the recruitment of RAD51 to sites of DSBs  and BRCA1. Interestingly loss of 53BP1 on top of BRCA1 deficiency restores a resistant phenotype in these radiosensitive cells (“synthetic viability”)  is a target for multiple PTMs, which may have important roles in the subsequent steps of HRR Figure . It has in vivo, but this modification is suppressed by a constitutive interaction of the SUMO-specific protease SENP6  also occurs in response to DNA breaks. RPA70 is sumoylated on at least two sites Upon formation of a RAD51 coated ssDNA the stability of this nucleoprotein filament is critical for the execution of HRR. In mammalian cells helicases like BLM or RECQ5 have been shown to dismantle RAD51 nucleoprotein filaments  by BCR-ABL has also been reported, and BCR-ABL stimulated expression of CtIP and increased DNA end-resection have been suggested as a mechanism  is associated with resistance to chemo- and radiotherapy  was identified in 1990  is a 3418 amino acids protein, harboring a specific domain consisting of about 30 degenerative BRC repeats that are responsible for the controlled formation of RAD51 and DMC1 nucleoprotein filaments during HRR and meiosis, respectively , and the NBS display mutations in genes involved in the repair of DSBs by HRR. Thus, in AT patients, ATM activity is abrogated and these individuals primarily develop lymphoid malignancies. The ATLD and NBS syndromes are associated with mutations in DNA damaging agents used in cancer treatment induce a spectrum of lesions in the DNA. These lesions are recognized by a variety of cellular lesion-specific DNA repair pathways that operate to remove them from the affected DNA molecules. It is commonly accepted that DSBs are substrates for NHEJ Lieber,  and HRR Our present understanding of DSB induction and repair allows us to postulate that combination of cytotoxic agents acting by inducing DSBs with inhibitors of DSB repair will enhance tumor cell killing – if this inhibition, or alternatively the induction of DSBs, could be somehow preferentially targeted to tumor cells. Similar arguments can be developed for other forms of DNA damage and other pathways of DNA repair.BRCA1 or BRCA2 mutations  polymerase 1 is known to be involved in SSB repair, BER, and NER in association with XRCC1, LIG3, PNK, PCNA, and FEN1  polymerase 1 inhibition shows synergistic interactions in combination with CHK1 inhibition and is thought to be mediated by the induction of apoptosis. CHK1 induced phosphorylation of ERK1/2 and H2AX is abolished after PARP-1 inhibition , have been known for decades, the underlying mechanisms remain largely unclear. However, the number of radiosensitizers that are found to inhibit HRR is growing. These include nucleoside and base analogs like gemcitabine (Wachters et al., There is also a growing list of inhibitory substances and therapeutics, which are less directly linked to DNA metabolism and damage response, but which are suggested to radiosensitize tumor cells by inhibiting HRR. These include the tyrosine kinase inhibitors imatinib and erlotinib (Chinnaiyan et al., Finally, it should be pointed out that IR, but also many widely used chemotherapeutic compounds induce large amounts of base damage, or generate replication errors that require mismatch repair for correction. As a result, it is possible to significantly improve cancer treatment by developing strategies for the simultaneous inhibition during treatment of some of these repair pathways, or by exploiting genetic defects in cancer cells in these repair pathways (Kinsella, It is evident from the above outline that a wealth of information and a variety of approaches are evolving that promise to improve the outcome of radiation therapy beyond the precise and more specific targeting of the radiation dose to the tumor. These approaches are aided and accelerated by rapid advances in synthetic chemistry and in protein structure information. As a result, they are likely to mature quickly and to open a new era of opportunities in radiation therapy. Radiation oncologists are likely to benefit significantly from these developments, if they closely follow them and quickly adapt them to the requirements of treatment of human tumors by IR.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Although statins are widely prescribed medications, there remains considerable variability in therapeutic response. Genetics can explain only part of this variability. Metabolomics is a global biochemical approach that provides powerful tools for mapping pathways implicated in disease and in response to treatment. Metabolomics captures net interactions between genome, microbiome and the environment. In this study, we used a targeted GC-MS metabolomics platform to measure a panel of metabolites within cholesterol synthesis, dietary sterol absorption, and bile acid formation to determine metabolite signatures that may predict variation in statin LDL-C lowering efficacy. Measurements were performed in two subsets of the total study population in the Cholesterol and Pharmacogenetics (CAP) study: Full Range of Response (FR), and Good and Poor Responders (GPR) were 100 individuals randomly selected from across the entire range of LDL-C responses in CAP. GPR were 48 individuals, 24 each from the top and bottom 10% of the LDL-C response distribution matched for body mass index, race, and gender. We identified three secondary, bacterial-derived bile acids that contribute to predicting the magnitude of statin-induced LDL-C lowering in good responders. Bile acids and statins share transporters in the liver and intestine; we observed that increased plasma concentration of simvastatin positively correlates with higher levels of several secondary bile acids. Genetic analysis of these subjects identified associations between levels of seven bile acids and a single nucleotide polymorphism (SNP), rs4149056, in the gene encoding the organic anion transporter SLCO1B1. These findings, along with recently published results that the gut microbiome plays an important role in cardiovascular disease, indicate that interactions between genome, gut microbiome and environmental influences should be considered in the study and management of cardiovascular disease. Metabolic profiles could provide valuable information about treatment outcomes and could contribute to a more personalized approach to therapy. Statins are HMG-CoA reductase inhibitors that are widely used to reduce plasma levels of LDL cholesterol (LDL-C) and the risk for coronary artery disease (CAD) Metabolomics brings powerful tools for mapping the metabolic state of individuals prior to treatment and global biochemical changes induced by drug treatment While it is well established that response to therapeutics can be affected by genetic and environmental factors, the enteric microbiome might also play a role in uncharacterized ways. Metabolomics provides a unique method to characterize the net interactions among these contributing factors. Numerous studies, by members of this group and others, have identified genetic polymorphisms that contribute to variability in the LDL-C response to statins Given that the primary cellular action of statins is well upstream of the factors that modulate plasma lipoprotein metabolism, there are many potential pathways that may act to influence the magnitude of the statin response. In this study, we sought to identify metabolites whose plasma levels predict LDL-C lowering response to statin treatment (simvastatin 40 mg/day) using a defined metabolomic approach. We measured a targeted panel of metabolites related to cholesterol metabolism in three known pathways: cholesterol synthesis, dietary sterol absorption, and bile acid formation. We detected significant correlations between gut-derived metabolites and simvastatin response. This supports further evidence that the genome, the microbiome and diet all contribute to mechanisms of variation of response to simvastatin.Two subgroups of subjects were selected from the 944 participants in the Cholesterol and Pharmacogenetics (CAP) study: 1) 100 individuals randomly selected from and representative of the entire range of LDL-C response, defined as the percentage change in LDL cholesterol from pretreatment levels ; and 2) 24 individuals each selected from the top and bottom 10% tails of the LDL-C response distribution  with matching of individuals from the two tails for body mass index, race, and gender . There wUsing a targeted metabolomics platform with which we evaluated 12 sterols and 14 bile acids, we observed in the randomly selected (FR) subjects a very strong correlation between a lower pretreatment level of several endogenous primary and secondary bile acids—taurocholic acid (TCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), glycochenodeoxycholic acid, (GCDCA) and glycoursodeoxycholic acid (GUDCA) —and greater response to the LDL lowering effects of simvastatin . Bile acA correlation matrix shows all correlations between the FR pretreatment metabolites and LDL-C response . All of We next evaluated samples from the tails of the spectrum of LDL-C response, that is, subsets of the best and worst responders to simvastatin therapy . As showSeparate correlation matrices for the good and the poor responders show all correlations of pretreatment metabolites within each group . There wPretreatment concentrations of two bile acids, CDCA and DCA, were positively correlated with on-treatment plasma simvastatin acid concentrations in the FR subjects . NeitherSeveral bile acids were correlated with simvastatin acid concentrations in the good and the poor responders, with borderline significant q-values . These iWe tested the FR subjects for associations of plasma lipid metabolites with SNP rs4149056 in the gene encoding the organic anion transporter SLCO1B1. In the full CAP study population, this SNP was strongly associated with fasting simvastatin acid concentration , consistent with earlier observations We also analyzed a second SLCO1B1 SNP  that was not associated with plasma simvastatin acid levels and found a significant correlation only with plasma stigmasterol concentration .Statins lower plasma LDL-C by blocking the activity of HMG-CoA reductase, thereby decreasing the synthesis of cholesterol and modifying downstream metabolic pathways. In our previous study we evaluated over 300 lipid species within eight lipid classes and found that baseline cholesterol ester and phospholipid metabolites correlated with LDL-C response to treatment In this study there were no strong correlations between pretreatment bile acid metabolites and HDL-C response to simvastatin (data not shown), which further supports the specificity of the relationship between the concentration of the bile acid metabolites and LDL-C response.Bile acids in plasma act as detergents to solubilize hydrophobic nutrient molecules including cholesterol, and other endogenous and exogenous sterols. Accordingly, the complex interplay of endogenous primary and bacterial metabolized secondary bile acids can affect the retention and metabolism of plasma cholesterol. Bile acids are known to be important endocrine signals, functioning in the systemic control of lipid levels, muscle function and immune cell regulation Lactobacillae bacteria isolated from fermented dairy products have been characterized by their ability to convert cholesterol to coprostanol and have been suggested as probiotic alternatives for reducing cholesterol levels In addition to secondary bile acids, we observed a correlation between response to simvastatin and higher pre-treatment levels of coprostanol (COPR) , and 3. Another potential basis for the relationship between gut microbial metabolism and statin efficacy is an effect on drug absorption or other factors affecting drug pharmacokinetics Our analyses identified primary and secondary bile acids for which pretreatment concentrations were correlated with on-treatment plasma simvastatin acid levels. Primary bile acids (CA and CDCA) and simvastatin are all metabolized by the P450 enzyme CYP3A4 SLCO1B1 SNP and plasma levels of simvastatin acid as well as specific primary and secondary bile acids. The SLCO1B1 transporter is of particular interest because it is known to transport simvastatin from plasma into the liver, and SNP rs4149056 has been associated with statin-induced myopathy in individuals treated with high dose simvastatin We speculate that the correlations between plasma simvastatin and bile acids occurred because transport of these compounds to or from the plasma is limiting. Therefore genetic polymorphisms which alter the activity or amount of hepatic transporters could result in changes in both simvastatin and bile acid concentrations. Genetic analyses of the CAP population, including the subjects in this study, have identified correlations between a The present findings point to the utility of metabolomic surveys for identifying predictors of clinical response that may have implications for assessing efficacy of this widely-used class of drugs. We have observed that the pretreatment levels of bile acids derived from gut bacteria and nutrient inputs are correlated with response to simvastatin. It is becoming increasingly clear that gut microbial symbiots are critical for normal digestion and defense, and also play an important role in development of disease Plasma samples were analyzed from participants in the Cholesterol and Pharmacogenetics (CAP) study—a trial in which 944 Caucasian and African-American men and women with total cholesterol levels of 160–400 mg/dL were treated with simvastatin 40 mg/d for 6 weeks. This study was designed to examine genetic and non-genetic factors affecting the response to simvastatin therapy in healthy, drug-naïve patients Two subgroups of subjects were selected for study. The first  consisted of 24 individuals selected from the top 10% of the LDL-C response distribution who were matched for body mass index (BMI), race, and gender to 24 individuals in the lowest 10% of responders, with response to therapy defined as the percentage change in LDL cholesterol from pretreatment levels. A second set of 100 individuals  was randomly selected from the entire CAP study, excluding subjects who had been selected for the initial GPR group. These subjects are representative of the population for age, race, gender, and BMI. Metabolomic analyses of statin-induced changes in the fatty acid content of the major lipid classes in the FR group have been reported recently As shown in Plasma LDL-C, HDL-C, apoAI and apoB were measured as described previously . Lipid extraction, solid-phase extraction, and capillary gas-liquid chromatography were used for quantitative analysis of sterols according to the method of Phillips et al. SLCO1B1 rs4149056 single nucleotide polymorphism (SNP) was performed by BeadArray technology .The levels of activated metabolite of simvastatin, simvastatin acid, were determined by mass spectrometry as described elsewhere We tested the correlation of pretreatment metabolites with drug response. Metabolites were log-transformed before correlation testing. For FR subjects, Spearman's correlation coefficient was used to obtain correlation coefficients between the pretreatment level of each metabolite with changes in LDL-C or HDL-C. Because changes in LDL-C and HDL-C are correlated with pretreatment LDL-C and HDL-C concentrations, respectively, the changes of these measurements were adjusted for their pretreatment levels \. Correlations among pretreatment metabolites were obtained by deriving Spearman's correlation coefficient between each pair. For GPR subjects, Wilcoxon rank sum tests were used to test differences in pretreatment metabolites between good responders and poor responders. Correlation maps were constructed using the algorithm in Ayroles et al.


The case of a female patient presenting with constrictive rheumatoid pericarditis and aortic incompetence secondary to valvular rheumatoid nodules is described along with a review of the literature with the aim to highlight this rare cause of aortic insufficiency. Baggenstoss and Rosenberg first described cardiac nodules in patients with rheumatoid arthritis (RA) in 1941, noting that these nodules had a similar histological appearance to rheumatoid nodules (RN) [A 34-year-old nonsmoking Caucasian woman presented to clinic with a one-year history of worsening shortness of breath and an exercise tolerance limited to 200 metres. Past medical history included a 10-year history of seropositive RA with marked deformities in her hands. The patient also had a pericardial effusion which was drained 3 years previously and a small persistent left pleural effusion, both of which were due to RA involvement and necessitated an increase in her steroid dose. Her medications included 12 mg once daily of oral prednisolone and anti-TNF alpha antibody (Infliximab) infusions every six weeks. A loud diastolic murmur was audible on auscultation over the aortic area. Echocardiography and cardiac magnetic resonance imaging showed severe aortic incompetence with no evidence of constrictive pericarditis. Coronary angiogram revealed no coronary artery disease, but right heart catheterisation was not performed.The patient was admitted for elective aortic valve replacement. Sternotomy revealed a thickened 3 mm pericardium densely adherent to the epicardium and central venous pressure fell from 20 to 12 mmHg following pericardiectomy. Aortotomy was performed and a thickened trileaflet valve with a retracted right coronary leaflet and fusion of the other two leaflets at the commissure see  was replCardiac lesions in RA are classified into two categories based on histological features: those due to a generalised, nonspecific chronic inflammatory-cell infiltrate, which include perimyocarditis, valvular fibrosis, and coronary vasculitis, and those due to specific rheumatoid nodule/granulomata formation, which can arise in the peri-endo-myocardium or valves. An autopsy study of 62 patients with a diagnosis of RA found 29% had evidence of nonspecific pericarditis, 19% myocarditis, and 19% arteritis; cardiac rheumatoid nodules were found in 2 cases (3%) [Subcutaneous RN is the most common extra-articular manifestation of RA, occurring in 40% of seropositive patients. Valvular abnormalities may occur in patients with RA but rarely present clinically as they are usually haemodynamically insignificant . It has The pathological features of these lesions are archetypal for this entity with the maturation of the nodule occurring in 3 stages: the acute inflammatory stage, the granulomatous stage, and the mature necrotic stage. The mature necrotic nodule has a 3-layer structure with the innermost zone containing eosinophilic acellular debris such as collagen, fibrin, and proteins. This area is surrounded by elongated palisading histiocytes and occasional multinucleated giant cells and finally by an outer layer of vascular connective tissue, macrophages, T-lymphocytes, and plasma cells.Nonspecific inflammation and fibrosis occur in the deep layer of the valve and the valve ring causing thickening and calcification of the valve. Valvular insufficiency occurs either as a result of dilatation of the valve ring or due to contraction and destruction of the valve leaflets. RN develops in either the annulus or the central portion of the valve cusps, impeding valve function and leading to simultaneous stenosis and incompetence. The development of RN is associated with higher levels of rheumatoid 4 factor, positive anticyclic citrullinated peptide antibody titres and more severe disease.Rare cases of stroke secondary to embolism from a ruptured valvular RN have been reported . SurgicaDespite up to 50% of patients with RA having involvement of the pericardium on postmortem examination, pericardial involvement does not seem to be related to disease duration or severity and less than 2% of patients exhibit symptoms . A case In conclusion, although valvular disease in RA is a known clinical entity, very rarely it is clinically significant. We described a case of severe aortic incompetence due to a very rare pathophysiology.