Search Results (9)

The standard immunosuppressive treatments in heart transplantation are calcineurin inhibitors, corticosteroids, and antimetabolite agents or inhibitors of the mammalian target of rapamycin. Pharmacogenetic studies show the impact on clinical course of genetic variability in genes that encode transporters, metabolizers, or molecular targets of immunosuppressants. The aim of this systematic review is to elucidate the role that pharmacogenetics of immunosuppressant drugs plays in clinical outcomes upon heart transplantation. PubMed, EMBASE, the Cochrane Central Register, and the Database of Abstracts of Reviews of Effects were searched without restrictions. The 64 studies analyzed followed these criteria: (1) were based on clinical data on heart transplantation patients; (2) analyzed the associations between polymorphisms and clinical response; (3) analyzed the impact of polymorphisms on immunosuppressant safety. CYP3A4/5 variants were associated with higher doses of tacrolimus, whereas POR*28 variants with lower doses—ABCB1, ABCC2, SLCO1B1, and SLC13A1—contribute to interindividual variability in drug absorption, distribution, and toxicity. An ABCC2 polymorphism (rs717620) was related to higher risk of graft rejection in pediatrics. Variations in HLA-G, TNF-α and TGF-β genes influence transplant rejection risk and immune response. Implementing pharmacogenetic screening of polymorphisms could enhance therapeutic outcomes by improving drug efficacy, reducing toxicity, and ultimately increasing heart graft survival rates. Strong evidence supports genotyping for CYP3A5 and TPMT, but further research is required for transporter genes and cytokine polymorphisms. Full article

Patients affected by familial hypercholesterolemia possess elevated low-density lipoprotein cholesterol and therefore have greater risk for cardiovascular disease. About 90% of familial hypercholesterolemia cases are associated with aberrant LDLR. Over 3500 LDLR variants have been identified, 15% of which are considered “pathogenic.” Given the genetic diversity of LDLR variants, specific variants rarely receive attention. However, investigators have proposed the critical evaluation of individual variants as a method to clarify knowledge and to resolve discrepancies in the literature. This article reviews p.(Val429Met) (rs28942078) in the areas of pathology, epidemiology, lipid-lowering therapy, and genetic testing. The p.(Val429Met) variant is associated with a missense point substitution in exon 9 of chromosome 19. Biochemical studies have found severely reduced low-density lipoprotein receptor protein in autologous and heterologous expression systems. Additionally, there are inconsistencies regarding the functional classification of p.(Val429Met). Considered to be of European origin, p.(Val429Met) is found in extant populations due to founder effects. Evidence from clinical trials have also demonstrated variable responses to newer lipid-lowering therapies in patients with a p.(Val429Met) variant. Proper clinical detection and adequate genetic testing have been shown to greatly improve outcomes. Future research may be aimed at resolving discrepancies to better comprehend the implications of familial hypercholesterolemia. Full article

Patients carrying the heterozygous A414G mutation in the HCN4 gene, which encodes the HCN4 protein, demonstrate moderate to severe bradycardia of the heart. Tetramers of HCN4 subunits compose the ion channels in the sinus node that carry the hyperpolarization-activated ‘funny’ current (I_f), also named the ‘pacemaker current’. I_f plays an essential modulating role in sinus node pacemaker activity. To assess the mechanism by which the A414G mutation results in sinus bradycardia, we first performed voltage clamp measurements on wild-type (WT) and heterozygous mutant HCN4 channels expressed in Chinese hamster ovary (CHO) cells. These experiments were performed at physiological temperature using the amphotericin-perforated patch-clamp technique. Next, we applied the experimentally observed mutation-induced changes in the HCN4 current of the CHO cells to I_f of the single human sinus node cell model developed by Fabbri and coworkers. The half-maximal activation voltage V_1/2 of the heterozygous mutant HCN4 current was 19.9 mV more negative than that of the WT HCN4 current (p < 0.001). In addition, the voltage dependence of the heterozygous mutant HCN4 current (de)activation time constant showed a −11.9 mV shift (p < 0.001) compared to the WT HCN4 current. The fully-activated current density, the slope factor of the activation curve, and the reversal potential were not significantly affected by the heterozygous A414G mutation. In the human sinus node computer model, the cycle length was substantially increased, almost entirely due to the shift in the voltage dependence of steady-state activation, and this increase was more prominent under vagal tone. The introduction of a passive atrial load into the model sinus node cell further reduced the beating rate, demonstrating that the bradycardia of the sinus node was even more pronounced by interactions between the sinus node and atria. In conclusion, the experimentally identified A414G-induced changes in I_f can explain the clinically observed sinus bradycardia in patients carrying the A414G HCN4 gene mutation. Full article

(1) Background. One of the causes of myocardial infarction (MI) with nonobstructive coronary arteries (MINOCA) is thrombus formation in situ followed by lysis, resulting in a morphologically normal angiogram but with an underlying prothrombotic state that is potentially predisposed to recurrence. Recent studies have shown that a subset of MINOCA patients may have thrombophilic conditions at screening. Objective: To compare the prothrombotic trend in MINOCA patients with that of subjects with MI and obstructive coronary arteries (MIOCA) by testing for known congenital thrombophilias and markers of coagulation activation. (2) Materials and methods. Screening included congenital thrombophilias (factor V Leiden; assessment of protein C, protein S, and antithrombin III) and eight genes. Of these, four genes represented the folate pathway enzymes: MTHFR 677 C>T (rs1801133), MTHFR 1298 A>C (rs1801131), MTR 2756 A>G (rs1805087), and MTRR 66 A>G (rs1801394). The other four genes represented the blood coagulation system: F13 (163 G>T) rs5985, F1 (−455 G>A) rs1800790, GP IIb–IIIa (1565 T>C) rs5918, and PAI-I (−675 5G>4G) rs1799889. Additionally, we examined the levels of homocysteine and lipoprotein (LP) (a). (3) Results. Our study included 269 patients: 114 MINOCA patients and 155 MIOCA patients with lesions of one coronary artery. The frequencies of polymorphisms in the genes of the blood coagulation system and the folate pathway did not differ between the groups. The following genes were associated with in-hospital mortality in the MINOCA group: MTHFR 1298 A>C rs1801131 (OR 8.5; 95% CI 1.67–43.1) and F1 (−455 G>A) rs1800790 (OR 5.8; 95% CI 1.1–27.8). In the MIOCA group, the following genes were associated with in-hospital mortality: MTHFR 1298 A>C rs1801131 (OR 9.1; 95% CI 2.8–28.9), F1 (−455 G>A) rs1800790 (OR 11.4; 95% CI 3.6–35.9), GP IIb–IIIa (1565 T>C) rs5918 (OR 10.5; 95% CI 3.5–30.8), and PAI-I (−675 5G>4G) rs1799889 (OR 12.9; 95% CI 4.2–39.7). We evaluated long-term outcomes (case fatality rate, recurrent MI, and stroke) over a period of 12 months in both groups. The variables associated with these outcomes were laboratory parameters, such as protein C deficiency, hyperhomocysteinemia, and a content of LP (a) > 30 mg/dL. However, we did not reveal the prognostic value of polymorphisms of the studied genes representing the blood coagulation system and the folate pathway. (4) Conclusion. We established no statistically significant differences between the MINOCA and MIOCA groups in the prevalence of congenital thrombophilias and the prevalence of folate pathway enzyme genes and blood coagulation system genes. The MTHFR 1298 A>C (rs1801131) and F1 (−455 G>A) rs1800790 genes were associated with in-hospital mortality in both groups. More significant prognostic factors in both groups during the one-year period were protein C deficiency, hyperhomocysteinemia, and LP (a) > 30 mg/dL. Full article

22q11.2 deletion syndrome is a phenotypic spectrum that encompasses DiGeorge syndrome (OMIM: 188400) and velocardiofacial syndrome (OMIM: 192430). It is caused by a 1.5–3.0 Mb hemizygous deletion of locus 22q11.2, which leads to characteristic facies, conotruncal cardiovascular malformations, velopharyngeal insufficiency, T-lymphocyte dysfunction due to thymic aplasia, and parathyroid hypoplasia, and, less frequently, neurological manifestations such as delayed psychomotor development or schizophrenia. This study aimed to describe a screening method for the diagnosis of 22q11.2 deletion syndrome in patients with Conotruncal Congenital Heart Disease (CCHD), using qPCR to detect the copy number of the TBX1 gene in a single DNA sample. A total of 23 patients were included; 21 with a biallelic prediction of the TBX1 copy number gene and 2 with a monoallelic prediction who were suspected to be positive and subjected to MLPA confirmation. One patient (4.34%) with truncus arteriosus CCHD was confirmed to have 22q11.2 deletion syndrome. We propose this approach as a possible newborn screening method for 22q11.2 deletion syndrome in CCHD patients. Full article

Epigenetics is defined as the study of inheritable changes in the gene expressions and phenotypes that occurs without altering the normal DNA sequence. These changes are mainly due to an alteration in chromatin or its packaging, which changes the DNA accessibility. DNA methylation, histone modification, and noncoding or microRNAs can best explain the mechanism of epigenetics. There are various DNA methylated enzymes, histone-modifying enzymes, and microRNAs involved in the cause of various CVDs (cardiovascular diseases) such as cardiac hypertrophy, heart failure, and hypertension. Moreover, various CVD risk factors such as diabetes mellitus, hypoxia, aging, dyslipidemia, and their epigenetics are also discussed together with CVDs such as CHD (coronary heart disease) and PAH (pulmonary arterial hypertension). Furthermore, different techniques involved in epigenetic chromatin mapping are explained. Among these techniques, the ChIP-on-chip guide is explained with regard to its role in cardiac hypertrophy, a final form of heart failure. This review focuses on different epigenetic factors that are involved in causing cardiovascular diseases. Full article

The deletion of the arginine 14 codon (R14del) in the phospholamban (PLN) gene is a rare cause of arrhythmogenic cardiomyopathy (ACM) and is associated with prevalent ventricular arrhythmias, heart failure, and sudden cardiac death. The pathophysiological mechanism which culminates in the ACM phenotype is multifactorial and mainly based on the alteration of the endoplasmic reticulum proteostasis, mitochondrial dysfunction and compromised Ca²⁺ cytosolic homeostasis. The symptoms of this condition are usually non-specific and consist of arrhythmia-related or heart failure-related manifestation; however, some peculiar diagnostic clues were detected, such as the T-wave inversion in the lateral leads, low QRS complexes voltages, mid-wall or epicardial fibrosis of the inferolateral wall of the left ventricle, and their presence should raise the suspicion of this condition. The risk stratification for sudden cardiac death is mandatory and several predictors were identified in recent years. However, the management of affected patients is often challenging due to the absence of specific prediction tools and therapies. This review aims to provide the current state of the art of PLN R14del cardiomyopathy, focusing on its pathophysiology, clinical manifestation, risk stratification for sudden cardiac death, and management. Full article

ABC transporters are a large family of membrane proteins that transport chemically diverse substrates across the cell membrane. Disruption of transport mechanisms mediated by ABC transporters causes the development of various diseases, including atherosclerosis. Methods: A bioinformatic analysis of a dataset from Gene Expression Omnibus (GEO) was performed. A GEO dataset containing data on gene expression levels in samples of atherosclerotic lesions and control arteries without atherosclerotic lesions from carotid, femoral, and infrapopliteal arteries was used for analysis. To evaluate differentially expressed genes, a bioinformatic analysis was performed in comparison groups using the limma package in R (v. 4.0.2) and the GEO2R and Phantasus tools (v. 1.11.0). Results: The obtained data indicate the differential expression of many ABC transporters belonging to different subfamilies. The differential expressions of ABC transporter genes involved in lipid transport, mechanisms of multidrug resistance, and mechanisms of ion exchange are shown. Differences in the expression of transporters in tissue samples from different arteries are established. Conclusions: The expression of ABC transporter genes demonstrates differences in atherosclerotic samples and normal arteries, which may indicate the involvement of transporters in the pathogenesis of atherosclerosis. Full article

Sarcolemmal membrane-associated proteins (SLMAPs) belong to the superfamily of tail-anchored membrane proteins known to regulate diverse biological processes, including protein trafficking and signal transduction. Mutations in SLMAP have been linked to Brugada and defective sodium channel Nav1.5 shuttling. The SLMAP gene is alternatively spliced to generate numerous isoforms, broadly defined as SLMAP1 (~35 kDa), SLMAP2 (~45 kDa) and SLMAP3 (~80–95 kDa), which are highly expressed in the myocardium. The SLMAP3 isoform exhibits ubiquitous expression carrying an FHA domain and is believed to negatively regulate Hippo signaling to dictate cell growth/death and differentiation. Using the αMHC-MerCreMer-flox system to target the SLMAP gene, we specifically deleted the SLMAP3 isoform in postnatal mouse hearts without any changes in the expression of SLMAP1/SLMAP2 isoforms. The in vivo analysis of mice with SLMAP3 cardiac deficiency revealed no significant changes to heart structure or function in young or aged mice without or with isoproterenol-induced stress. SLMAP3-deficient hearts revealed no obvious differences in cardiac size, function or hypertrophic response. Further, the molecular analysis indicated that SLMAP3 loss had a minor impact on sodium channel (Nav1.5) expression without affecting cardiac electrophysiology in postnatal myocardium. Surprisingly, the loss of SLMAP3 did not impact Hippo signaling in postnatal myocardium. We conclude that the FHA domain-containing SLMAP3 isoform has no impact on Hippo signaling or sodium channels in postnatal myocardium, which is able to function and respond normally to stress in its absence. Whether SLMAP1/SMAP2 isoforms can compensate for the loss of SLMAP3 in the affairs of the postnatal heart remains to be determined. Full article