A Novel Variant in TPM3 Causing Muscle Weakness and Concomitant Hypercontractile Phenotype.

A novel variant of unknown significance c.8A > G (p.Glu3Gly) in TPM3 was detected in two unrelated families. TPM3 encodes the transcript variant Tpm3.12 (NM_152263.4), the tropomyosin isoform specifically expressed in slow skeletal muscle fibers. The patients presented with slowly progressive muscle weakness associated with Achilles tendon contractures of early childhood onset. Histopathology revealed features consistent with a nemaline rod myopathy. Biochemical in vitro assays performed with reconstituted thin filaments revealed defects in the assembly of the thin filament and regulation of actin-myosin interactions. The substitution p.Glu3Gly increased polymerization of Tpm3.12, but did not significantly change its affinity to actin alone. Affinity of Tpm3.12 to actin in the presence of troponin ± Ca2+ was decreased by the mutation, which was due to reduced interactions with troponin. Altered molecular interactions affected Ca2+-dependent regulation of the thin filament interactions with myosin, resulting in increased Ca2+ sensitivity and decreased relaxation of the actin-activated myosin ATPase activity. The hypercontractile molecular phenotype probably explains the distal joint contractions observed in the patients, but additional research is needed to explain the relatively mild severity of the contractures. The slowly progressive muscle weakness is most likely caused by the lack of relaxation and prolonged contractions which cause muscle wasting. This work provides evidence for the pathogenicity of the TPM3 c.8A > G variant, which allows for its classification as (likely) pathogenic.

Molecular Mechanisms of Deregulation of Muscle Contractility Caused by the R168H Mutation in TPM3 and Its Attenuation by Therapeutic Agents.

The substitution for Arg168His (R168H) in γ-tropomyosin (TPM3 gene, Tpm3.12 isoform) is associated with congenital muscle fiber type disproportion (CFTD) and muscle weakness. It is still unclear what molecular mechanisms underlie the muscle dysfunction seen in CFTD. The aim of this work was to study the effect of the R168H mutation in Tpm3.12 on the critical conformational changes that myosin, actin, troponin, and tropomyosin undergo during the ATPase cycle. We used polarized fluorescence microscopy and ghost muscle fibers containing regulated thin filaments and myosin heads (myosin subfragment-1) modified with the 1,5-IAEDANS fluorescent probe. Analysis of the data obtained revealed that a sequential interdependent conformational-functional rearrangement of tropomyosin, actin and myosin heads takes place when modeling the ATPase cycle in the presence of wild-type tropomyosin. A multistep shift of the tropomyosin strands from the outer to the inner domain of actin occurs during the transition from weak to strong binding of myosin to actin. Each tropomyosin position determines the corresponding balance between switched-on and switched-off actin monomers and between the strongly and weakly bound myosin heads. At low Ca2+, the R168H mutation was shown to switch some extra actin monomers on and increase the persistence length of tropomyosin, demonstrating the freezing of the R168HTpm strands close to the open position and disruption of the regulatory function of troponin. Instead of reducing the formation of strong bonds between myosin heads and F-actin, troponin activated it. However, at high Ca2+, troponin decreased the amount of strongly bound myosin heads instead of promoting their formation. Abnormally high sensitivity of thin filaments to Ca2+, inhibition of muscle fiber relaxation due to the appearance of the myosin heads strongly associated with F-actin, and distinct activation of the contractile system at submaximal concentrations of Ca2+ can lead to muscle inefficiency and weakness. Modulators of troponin (tirasemtiv and epigallocatechin-3-gallate) and myosin (omecamtiv mecarbil and 2,3-butanedione monoxime) have been shown to more or less attenuate the negative effects of the tropomyosin R168H mutant. Tirasemtiv and epigallocatechin-3-gallate may be used to prevent muscle dysfunction.

Assessment and Management of Cardiotoxicity in Hematologic Malignancies.

With the increasing overall survival of cancer patients due to recent discoveries in oncology, the incidence of side effects is also rising, and along with secondary malignancies, cardiotoxicity is one of the most concerning side effects, affecting the quality of life of cancer survivors. There are two types of cardiotoxicity associated with chemotherapy; the first one is acute, life-threatening but, fortunately, in most of the cases, reversible; and the second one is with late onset and mostly irreversible. The most studied drugs associated with cardiotoxicity are anthracyclines, but many new agents have demonstrated unexpected cardiotoxic effect, including those currently used in multiple myeloma treatment (proteasome inhibitors and immunomodulatory agents), tyrosine kinase inhibitors used in the treatment of chronic myeloid leukemia and some forms of acute leukemia, and immune checkpoint inhibitors recently introduced in treatment of refractory lymphoma patients. To prevent irreversible myocardial damage, early recognition of cardiac toxicity is mandatory. Traditional methods like echocardiography and magnetic resonance imaging are capable of detecting structural and functional changings, but unable to detect early myocardial damage; therefore, more sensible biomarkers like troponins and natriuretic peptides have to be introduced into the current practice. Baseline assessment of patients allows the identification of those with high risk for cardiotoxicity, while monitoring during and after treatment is important for early detection of cardiotoxicity and prompt intervention.

Protective Effects of Apocynum venetum Against Pirarubicin-Induced Cardiotoxicity.

Pirarubicin (THP) is an anthracycline antibiotic, frequently used for the treatment of various human cancers. Unfortunately, the clinical effectiveness of THP is limited by its dose-related cardiotoxicity. Apocynum leaf extract is an extract of the dried leaves of Apocynum venetum L. (a member of the Apocynaceae family, AVLE) that has many positive effects on the cardiovascular system and is widely consumed as tea in China. In this study we established a cardiactoxicity rat model, which showed that pretreatment with AVLE attenuated THP-induced myocardial histopathological injury, electrocardiogram abnormalities, and cardiac dysfunction. AVLE also significantly reduced serum levels of malondialdehyde (MDA), brain natriuretic peptide (BNP), creatine kinase (CK-MB), cardiac troponin (CTnT), and lactate dehydrogenase (LDH); and increased serum superoxide dismutase (SOD) levels. Treatment with AVLE or dexrazoxane (DZR) resulted in an increase Cytochrome C (cytc) in the mitochondria and reduced Cytc and cleaved-caspase-3 levels (p<0.05) in cytoplasm. We also found that AVLE significantly reduced voltage-dependent anion channel 1 (VDAC1), adenosine nucleotide transporter 1 (ANT1), and cyclophilin D (CYPD) mRNA expression (p<0.05). Furthermore, AVLE appeared to exert therapeutic effects in a dose-dependent manner. Our study suggests the anti-oxidant and anti-apoptotic properties of AVLE may be responsible for the observed cardioprotective effects.

Expression of troponin subunits in the rat renal afferent arteriole.

Vascular smooth muscle cells of the renal afferent arteriole are unusual in that they must be able to contract very rapidly in response to a sudden increase in systemic blood pressure in order to protect the downstream glomerular capillaries from catastrophic damage. We showed that this could be accounted for, in part, by exclusive expression, at the protein level, of the "fast" (B) isoforms of smooth muscle myosin II heavy chains in the afferent arteriole, in contrast to other vascular smooth muscle cells such as the rat aorta and efferent arteriole which express exclusively the "slow" (A) isoforms (Shiraishi et al. (2003) FASEB. J. 17, 2284-2286). As contraction of the more rapidly contracting striated (skeletal and cardiac) muscles is regulated by the thin filament-associated troponin (Tn) system, we hypothesized that Tn or a Tn-like system may exist in afferent arteriolar cells and contribute to the unusually rapid contraction of this tissue in response to increased intraluminal pressure. We examined the expression of TnC (Ca2+ -binding subunit), TnI (inhibitory subunit), and TnT (tropomyosin-binding subunit) in vascular smooth muscle cells of the rat renal afferent arteriole at the mRNA level. Fast-twitch skeletal muscle and slow-twitch skeletal muscle/cardiac TnC isoforms and slow-twitch skeletal muscle and cardiac TnI isoforms were detected by reverse transcription-polymerase chain reaction (RT-PCR) and confirmed by cDNA sequencing. Furthermore, cardiac and slow-twitch skeletal muscle TnI isoforms, but not fast-twitch skeletal muscle TnI, were detected in isolated afferent arterioles at the protein level by proximity ligation assay. Finally, striated muscle myosin II heavy chain expression was identified in isolated rat afferent arterioles by RT-PCR. We conclude that, in addition to Ca2+ -mediated phosphorylation of myosin II regulatory light chains, contraction of the afferent arteriole may be regulated by a mechanism normally associated with the much more rapidly contracting cardiac and skeletal muscles, which involves Ca2+ binding to TnC, leading to alleviation of inhibition of the actomyosin MgATPase by TnI and tropomyosin and rapid contraction of the vessel.

Ca2+-Binding Proteins of the EF-Hand Superfamily: Diagnostic and Prognostic Biomarkers and Novel Therapeutic Targets.

A multitude of Ca2+-sensor proteins containing the specific Ca2+-binding motif (helix-loop-helix, called EF-hand) are of major clinical relevance in a many human diseases. Measurements of troponin, the first intracellular Ca-sensor protein to be discovered, is nowadays the "gold standard" in the diagnosis of patients with acute coronary syndrome (ACS). Mutations have been identified in calmodulin and linked to inherited ventricular tachycardia and in patients affected by severe cardiac arrhythmias. Parvalbumin, when introduced into the diseased heart by gene therapy to increase contraction and relaxation speed, is considered to be a novel therapeutic strategy to combat heart failure. S100 proteins, the largest subgroup with the EF-hand protein family, are closely associated with cardiovascular diseases, various types of cancer, inflammation, and autoimmune pathologies. The intention of this review is to summarize the clinical importance of this protein family and their use as biomarkers and potential drug targets, which could help to improve the diagnosis of human diseases and identification of more selective therapeutic interventions.

EPA and DHA Inhibit Myogenesis and Downregulate the Expression of Muscle-related Genes in C2C12 Myoblasts.

This study was conducted to elucidate the biological effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on cell proliferation, differentiation and gene expression in C2C12 myoblasts. C2C12 were treated with various concentrations of EPA or DHA under proliferation and differentiation conditions. Cell viability was analyzed using cell counting kit-8 assays (CCK-8). The Edu assays were performed to analyze cell proliferation. To analyze cell differentiation, the expressions of myogenic marker genes were determined at the transcriptional and translational levels by qRT-PCR, immunoblotting and immunofluorescence. Global gene expression patterns were characterized using RNA-sequencing. Phosphorylation levels of ERK and Akt were examined by immunoblotting. Cell viability and proliferation was significantly inhibited after incubation with EPA (50 and 100 µM) or DHA (100 µM). Both EPA and DHA suppressed C2C12 myoblasts differentiation. RNA-sequencing analysis revealed that some muscle-related genes were significantly downregulated following EPA or DHA (50 µM) treatment, including insulin-like growth factor 2 (IGF-2), troponin T3 (Tnnt3), myoglobin (Mb), myosin light chain phosphorylatable fast skeletal muscle (Mylpf) and myosin heavy polypeptide 3 (Myh3). IGF-2 was crucial for the growth and differentiation of skeletal muscle and could activate the PI3K/Akt and the MAPK/ERK cascade. We found that EPA and DHA (50 µM) decreased the phosphorylation levels of ERK1/2 and Akt in C2C12 myoblasts. Thus, this study suggested that EPA and DHA exerted an inhibitory effect on myoblast proliferation and differentiation and downregulated muscle-related genes expression.

The Genetic and Molecular Bases for Hypertrophic Cardiomyopathy: The Role for Calcium Sensitization.

Hypertrophic cardiomyopathy (HCM) affects millions of people around the world as one of the most common genetic heart disorders and leads to cardiac ischemia, heart failure, dysfunction of other organ systems, and increased risk for sudden unexpected cardiac deaths. HCM can be caused by single-point mutations, insertion or deletion mutations, or truncation of cardiac myofilament proteins. The molecular mechanism that leads to disease progression and presentation is still poorly understood, despite decades of investigations. However, recent research has made dramatic advances in the understanding of HCM disease development. Studies have shown that increased calcium sensitivity is a universal feature in HCM. At the molecular level, increased crossbridge force (or power) generation resulting in hypercontractility is the prominent feature. Thus, calcium sensitization/hypercontractility is emerging as the primary stimulus for HCM disease development and phenotypic expression. Cross-bridge inhibition has been shown to halt HCM presentation, and myofilament desensitization appears to reduce lethal arrhythmias in animal models of HCM. These advances in basic research will continue to deepen the knowledge of HCM pathogenesis and are beginning to revolutionize the management of HCM.

Clinically Divergent Mutation Effects on the Structure and Function of the Human Cardiac Tropomyosin Overlap.

The progression of genetically inherited cardiomyopathies from an altered protein structure to clinical presentation of disease is not well understood. One of the main roadblocks to mechanistic insight remains a lack of high-resolution structural information about multiprotein complexes within the cardiac sarcomere. One example is the tropomyosin (Tm) overlap region of the thin filament that is crucial for the function of the cardiac sarcomere. To address this central question, we devised coupled experimental and computational modalities to characterize the baseline function and structure of the Tm overlap, as well as the effects of mutations causing divergent patterns of ventricular remodeling on both structure and function. Because the Tm overlap contributes to the cooperativity of myofilament activation, we hypothesized that mutations that enhance the interactions between overlap proteins result in more cooperativity, and conversely, those that weaken interaction between these elements lower cooperativity. Our results suggest that the Tm overlap region is affected differentially by dilated cardiomyopathy-associated Tm D230N and hypertrophic cardiomyopathy-associated human cardiac troponin T (cTnT) R92L. The Tm D230N mutation compacts the Tm overlap region, increasing the cooperativity of the Tm filament, contributing to a dilated cardiomyopathy phenotype. The cTnT R92L mutation causes weakened interactions closer to the N-terminal end of the overlap, resulting in decreased cooperativity. These studies demonstrate that mutations with differential phenotypes exert opposite effects on the Tm-Tn overlap, and that these effects can be directly correlated to a molecular level understanding of the structure and dynamics of the component proteins.

The structural basis of alpha-tropomyosin linked (Asp230Asn) familial dilated cardiomyopathy.

Recently, linkage analysis of two large unrelated multigenerational families identified a novel dilated cardiomyopathy (DCM)-linked mutation in the gene coding for alpha-tropomyosin (TPM1) resulting in the substitution of an aspartic acid for an asparagine (at residue 230). To determine how a single amino acid mutation in α-tropomyosin (Tm) can lead to a highly penetrant DCM we generated a novel transgenic mouse model carrying the D230N mutation. The resultant mouse model strongly phenocopied the early onset of cardiomyopathic remodeling observed in patients as significant systolic dysfunction was observed by 2months of age. To determine the precise cellular mechanism(s) leading to the observed cardiac pathology we examined the effect of the mutation on Ca2+ handling in isolated myocytes and myofilament activation in vitro. D230N-Tm filaments exhibited a reduced Ca2+ sensitivity of sliding velocity. This decrease in sensitivity was coupled to increase in the peak amplitude of Ca2+ transients. While significant, and consistent with other DCMs, these measurements are comprised of complex inputs and did not provide sufficient experimental resolution. We then assessed the primary structural effects of D230N-Tm. Measurements of the thermal unfolding of D230N-Tm vs WT-Tm revealed an increase in stability primarily affecting the C-terminus of the Tm coiled-coil. We conclude that the D230N-Tm mutation induces a decrease in flexibility of the C-terminus via propagation through the helical structure of the protein, thus decreasing the flexibility of the Tm overlap and impairing its ability to regulate contraction. Understanding this unique structural mechanism could provide novel targets for eventual therapeutic interventions in patients with Tm-linked cardiomyopathies.

The Role of Biomarkers in Detection of Cardio-toxicity.

The goal of this paper is to review the current literature on the role of biomarkers in the detection and management of patients with cardio-oncologic disease. The role of biomarker surveillance in patients with known cardiac disease, as a result of chemotherapy or with the potential to develop cardio-toxicity, will be discussed. In addition, the studies surrounding sub-clinical cardiac toxicity monitoring during therapy, identification of high-risk patients prior to therapy, and tailoring oncologic therapies to potential biomarker risk profiles are reviewed. Based on evidence, to date, troponin and natriuretic peptides have the greatest potential to detect sub-clinical cardiac dysfunction and even tailor therapy to prevent progression based on biomarker profiles. Finally, future directions for potential utilization of novel biomarkers for the improvement of care of patients in the field of cardio-oncology are discussed.

Effect of Cardiomyopathic Mutations in Tropomyosin on Calcium Regulation of the Actin-Myosin Interaction in Skeletal Muscle.

Tropomyosin plays an important role in the regulation of actin-myosin interaction in striated muscles. Mutations in the tropomyosin gene disrupt actin-myosin interaction and lead to myopathies and cardiomyopathies. Tropomyosin with mutations in the α-chain is expressed in both the myocardium and skeletal muscles. We studied the effect of mutations in the α-chain of tropomyosin related to hypertrophic (D175N and E180G) and dilated cardiomyopathies (E40K and E54K) on calcium regulation of the actin-myosin interaction in skeletal muscles. We analyzed the calcium-dependent sliding velocity of reconstructed thin filaments containing F-actin, troponin, and tropomyosin over myosin surface in an in vitro motility assay. Mutations D175N and E180G in tropomyosin increased the sliding velocity and its calcium sensitivity, while mutation E40K reduced both these parameters. E54K mutation increased the sliding velocity of thin filaments, but did not affect its calcium sensitivity.

Calcium Ions in Inherited Cardiomyopathies.

Inherited cardiomyopathies are a known cause of heart failure, although the pathways and mechanisms leading from mutation to the heart failure phenotype have not been elucidated. There is strong evidence that this transition is mediated, at least in part, by abnormal intracellular Ca(2+) handling, a key ion in ventricular excitation, contraction and relaxation. Studies in human myocytes, animal models and in vitro reconstituted contractile protein complexes have shown consistent correlations between Ca(2+) sensitivity and cardiomyopathy phenotype, irrespective of the causal mutation. In this review we present the available data about the connection between mutations linked to familial hypertrophic (HCM), dilated (DCM) and restrictive (RCM) cardiomyopathy, right ventricular arrhythmogenic cardiomyopathy/dysplasia (ARVC/D) as well as left ventricular non-compaction and the increase or decrease in Ca(2+) sensitivity, together with the results of attempts to reverse the manifestation of heart failure by manipulating Ca(2+) homeostasis.

Sequential Binding of MEIS1 and NKX2-5 on the Popdc2 Gene: A Mechanism for Spatiotemporal Regulation of Enhancers during Cardiogenesis.

The homeobox transcription factors NKX2-5 and MEIS1 are essential for vertebrate heart development and normal physiology of the adult heart. We show that, during cardiac differentiation, the two transcription factors have partially overlapping expression patterns, with the result that as cardiac progenitors from the anterior heart field differentiate and migrate into the cardiac outflow tract, they sequentially experience high levels of MEIS1 and then increasing levels of NKX2-5. Using the Popdc2 gene as an example, we also show that a significant proportion of target genes for NKX2-5 contain a binding motif recognized by NKX2-5, which overlaps with a binding site for MEIS1. Binding of the two factors to such overlapping sites is mutually exclusive, and this provides a simple regulatory mechanism for spatial and temporal synchronization of a common pool of targets between NKX2-5 and MEIS1.

Troponin-like regulation in muscle thin filaments of the mussel Crenomytilus grayanus (Bivalvia: Mytiloida).

Muscles of bivalve molluscs have double calcium regulation--myosin-linked and actin-linked. While the mechanism of myosin-linked regulation is sufficiently studied, there is still no consensus on the mechanism of actin-linked regulation. Earlier we showed a high degree of Ca2+-sensitivity of thin filaments from the adductor muscle of the mussel Crenomytilus grayanus (Mytiloida). In order to elucidate the nature of this regulation, we isolated the fraction of minor proteins from the mussel thin filaments, which confers Ca2+-sensitivity to reconstituted actomyosin-tropomyosin. Proteins of this fraction, ABP-19, ABP-20, and ABP-28, were chromatographically purified and identified. According to the results of mass spectrometry and Western blot analysis, as well as by their functional properties, these mussel actin-binding proteins appeared to correspond to the troponin components from the skeletal muscles of vertebrates (TnC, TnI and TnT). The reconstituted mussel troponin complex confers to actomyosin-tropomyosin more than 80% Ca2+-sensitivity. The in vivo molar ratio of actin/tropomyosin/troponin was calculated to be 7:1:0.5, i.e., the content of troponin in mussel thin filaments is two times lower than in thin filaments of skeletal muscles of vertebrates. These data demonstrate that troponin-like regulation found in the catch muscle of the mussel C. grayanus is present at least in two suborders of bivalves: Pectinoida and Mytiloida.

Molecular Analysis of Mixed Endometrioid and Serous Adenocarcinoma of the Endometrium.

BACKGROUND: The molecular biology and cellular origins of mixed type endometrial carcinomas (MT-ECs) are poorly understood, and a Type II component of 10 percent or less may confer poorer prognoses. METHODOLOGY/PRINCIPAL FINDINGS: We studied 10 cases of MT-EC (containing endometrioid and serous differentiation), 5 pure low-grade endometrioid adenocarcinoma (EAC) and 5 pure uterine serous carcinoma (USC). Endometrioid and serous components of the MT-ECs were macrodissected and the expression of 60 candidate genes compared between MT-EC, pure USC and pure EAC. We found that four genes were differentially expressed when MT-ECs were compared to pure low-grade EAC: CDKN2A (P = 0.006), H19 (P = 0.010), HOMER2 (P = 0.009) and TNNT1 (P = 0.006). Also while we found that even though MT-ECs closely resembled the molecular profiles of pure USCs, they also exhibit lower expression of PAX8 compared to all pure cases combined (P = 0.035). CONCLUSION: Our data suggest that MT-EC exhibits the closest molecular and epidemiological similarities to pure USC and supports clinical observations that suggest patients with MT-EC should receive the same treatment as patients with pure serous carcinoma. Novel specific markers of MT-EC could be of diagnostic utility and could represent novel therapeutic targets in the future.

Ca++-sensitizing mutations in troponin, P(i), and 2-deoxyATP alter the depressive effect of acidosis on regulated thin-filament velocity.

Repeated, intense contractile activity compromises the ability of skeletal muscle to generate force and velocity, resulting in fatigue. The decrease in velocity is thought to be due, in part, to the intracellular build-up of acidosis inhibiting the function of the contractile proteins myosin and troponin; however, the underlying molecular basis of this process remains poorly understood. We sought to gain novel insight into the decrease in velocity by determining whether the depressive effect of acidosis could be altered by 1) introducing Ca(++)-sensitizing mutations into troponin (Tn) or 2) by agents that directly affect myosin function, including inorganic phosphate (Pi) and 2-deoxy-ATP (dATP) in an in vitro motility assay. Acidosis reduced regulated thin-filament velocity (VRTF) at both maximal and submaximal Ca(++) levels in a pH-dependent manner. A truncated construct of the inhibitory subunit of Tn (TnI) and a Ca(++)-sensitizing mutation in the Ca(++)-binding subunit of Tn (TnC) increased VRTF at submaximal Ca(++) under acidic conditions but had no effect on VRTF at maximal Ca(++) levels. In contrast, both Pi and replacement of ATP with dATP reversed much of the acidosis-induced depression of VRTF at saturating Ca(++). Interestingly, despite producing similar magnitude increases in VRTF, the combined effects of Pi and dATP were additive, suggesting different underlying mechanisms of action. These findings suggest that acidosis depresses velocity by slowing the detachment rate from actin but also by possibly slowing the attachment rate.

Decreased circulating microRNA-223 level predicts high on-treatment platelet reactivity in patients with troponin-negative non-ST elevation acute coronary syndrome.

To investigate the relationship between circulating microRNA 223 (miR-223) levels and clopidogrel responsiveness in patients with coronary heart disease. A total of 62 consecutive patients with troponin-negative non-ST elevation acute coronary syndrome (NSTE-ACS) scheduled for elective percutaneous coronary intervention were enrolled. The plasma circulating miR-223 levels were quantified by real-time PCR, and platelet reactivity was determined by platelet reactivity index (PRI), measured by vasodilator-stimulated phosphoprotein (VASP) phosphorylation flow cytometry after 300 mg (for at least 24 h) or 75 mg clopidogel (for at least 5 days) plus aspirin treatment. All subjects were dichotomized according to PRI median (normal-responders: PRI ≤ 56.3%, n = 31 and low-responders: PRI > 56.3%, n = 31). Compared with normal-responders, circulating miR-223 level was significantly decreased in low-responders (P = 0.007). In addition, miR-223 level was statistically correlated with PRI (Spearman r = -0.379, P = 0.002). Stepwise binary logistic regression analysis revealed that among factors that potentially influence platelet reactivity (CYP2C19*2/*3 loss-of-function genotypes, use of calcium channel blockers/proton-pump inhibitors, age, diabetes and smoking), decreased circulating miR-223 level was the only independent predictor for the presence of PRI-determined lower responders (OR 0.111, 95% CI 0.018-0.692, P = 0.019). Our data suggest that circulating miR-223 may serve as a novel biomarker for assessment of clopidogrel responsiveness in troponin-negative NSTE-ACS patients.

Tissue Doppler imaging and plasma N-terminal probrain natriuretic peptide for the identification of hypertrophic cardiomyopathy mutation carriers.

Previous studies have shown that tissue Doppler imaging (TDI) is able to identify mutation carriers of hypertrophic cardiomyopathy (HC) before the development of the clinical phenotype. However, data are scarce and have sometimes been controversial. We performed a systematic study that included conventional echocardiography, TDI, and plasma NT-probrain natriuretic peptide (NT-proBNP) measurement to evaluate the parameters that could identify HC mutation carriers. A total of 138 genotyped subjects were included and divided into 3 groups: group 1, those with HC (n = 62); group 2, mutation carriers (first-degree relatives with a positive genotype but negative phenotype; n = 34); and group 3, controls (first-degree relatives with a negative genotype and phenotype; n = 42). An echocardiographic study, including TDI, was performed on all subjects, and a TDI-derived index (global function index) was also determined. The age-adjusted mean differences in the echocardiographic and TDI parameters and NT-proBNP levels were compared among the 3 groups. Compared with the HC group, the carriers had significantly higher mean E' velocities, lower mean E/E' ratio, higher mean S' velocities, and lower mean global function index and NT-proBNP values. The carriers and controls did not differ significantly either in the echocardiographic parameters studied or in the NT-proBNP levels. In conclusion, the echocardiographic and TDI parameters and NT-proBNP levels cannot be used to identify the HC mutation carrier state and therefore do not appear to be reliable for the purpose of making a preclinical diagnosis of the disease.

Myocardial infarction marker levels are influenced by prothrombin and tumor necrosis factor-α gene polymorphisms in young patients.

Polymorphisms of genes encoding key factors for the control and activation of inflammatory response and coagulation cascade regulation may play a role in genetic susceptibility to acute myocardial infarction (AMI). This study sought to analyze the effect of TNF -308G/A and pro-thrombin (FII) 20210G/A polymorphisms on the laboratory parameters of young patients affected by AMI. Results indicated that TNF -308A positive genotype frequencies were increased in these patients and that a genetically determined higher production of TNF-α is associated in young subjects to a more severe cardiac damage as depicted by higher levels of troponin, Creatine kinase-MB Isoenzyme (mCK-MB) and a significant increased plasma fibrinogen levels. Similar and probably additive effects on might have a genetically determined increased production of pro-thrombin even if no significant differences in genotype frequencies of pro-thrombin (FII) 20210G/A polymorphisms were observed in this study. All together these results, indicating the relationship among genetically determined TNFα and FII production and increased levels of tissue damage markers of AMI, suggest that a complex genetic background, might be involved in susceptibility to AMI in young men influencing the extension and severity of the disease.