Kv beta complex facilitates exercise-induced augmentation of myocardial perfusion and cardiac growth.

The oxygen sensitivity of voltage-gated potassium (Kv) channels regulates cardiovascular physiology. Members of the Kv1 family interact with intracellular Kvß proteins, which exhibit aldo-keto reductase (AKR) activity and confer redox sensitivity to Kv channel gating. The Kvß proteins contribute to vasoregulation by controlling outward K+ currents in smooth muscle upon changes in tissue oxygen consumption and demand. Considering exercise as a primary physiological stimulus of heightened oxygen demand, the current study tested the role of Kvß proteins in exercise performance, exercise-induced adaptations in myocardial perfusion, and physiological cardiac growth. Our findings reveal that genetic ablation of Kvß2 proteins diminishes baseline exercise capacity in mice and attenuates the enhancement in exercise performance observed after long-term training. Moreover, we demonstrate that Kvß2 proteins are critical for exercise-mediated enhancement in myocardial perfusion during cardiac stress as well as adaptive changes in cardiac structure. Our results underscore the importance of Kvß proteins in metabolic vasoregulation, highlighting their role in modulating both exercise capacity and cardiovascular benefits associated with training. Furthermore, our study sheds light on a novel molecular target for enhancing exercise performance and improving the health benefits associated with exercise training in patients with limited capacity for physical activity.

Metabolic signatures of pregnancy-induced cardiac growth.

The goal of this study was to develop an atlas of the metabolic, transcriptional, and proteomic changes that occur with pregnancy in the maternal heart. Timed pregnancy studies in FVB/NJ mice revealed a significant increase in heart size by day 8 of pregnancy (midpregnancy; MP), which was sustained throughout the rest of the term compared with nonpregnant control mice. Cardiac hypertrophy and myocyte cross-sectional area were highest 7 days after birth (postbirth; PB) and were associated with significant increases in end-diastolic and end-systolic left ventricular volumes and higher cardiac output. Metabolomics analyses revealed that by day 16 of pregnancy (late pregnancy; LP) metabolites associated with nitric oxide production as well as acylcholines, sphingomyelins, and fatty acid species were elevated, which coincided with a lower activation state of phosphofructokinase and higher levels of pyruvate dehydrogenase kinase 4 (Pdk4) and ß-hydroxybutyrate dehydrogenase 1 (Bdh1). In the postpartum period, urea cycle metabolites, polyamines, and phospholipid levels were markedly elevated in the maternal heart. Cardiac transcriptomics in LP revealed significant increases in not only Pdk4 and Bdh1 but also genes that regulate glutamate and ketone body oxidation, which were preceded in MP by higher expression of transcripts controlling cell proliferation and angiogenesis. Proteomics analysis of the maternal heart in LP and PB revealed significant reductions in several contractile filament and mitochondrial subunit complex proteins. Collectively, these findings describe the coordinated molecular changes that occur in the maternal heart during and after pregnancy.NEW & NOTEWORTHY Little is known of the underlying molecular and cellular mechanisms that contribute to pregnancy-induced cardiac growth. Several lines of evidence suggest that changes in cardiac metabolism may contribute. Here, we provide a comprehensive metabolic atlas of the metabolomic, proteomic, and transcriptomic changes occurring in the maternal heart. We show that pregnancy-induced cardiac growth is associated with changes in glycerophospholipid, nucleotide, and amino acid metabolism, with reductions in cardiac glucose catabolism. Collectively, these results suggest that substantial metabolic changes occur in the maternal heart during and after pregnancy.

Chronic Benzene Exposure Aggravates Pressure Overload-Induced Cardiac Dysfunction.

Benzene is a ubiquitous environmental pollutant abundant in household products, petrochemicals, and cigarette smoke. Benzene is a well-known carcinogen in humans and experimental animals; however, little is known about the cardiovascular toxicity of benzene. Recent population-based studies indicate that benzene exposure is associated with an increased risk for heart failure. Nonetheless, it is unclear whether benzene exposure is sufficient to induce and/or exacerbate heart failure. We examined the effects of benzene (50 ppm, 6 h/day, 5 days/week, and 6 weeks) or high-efficiency particulate absorbing-filtered air exposure on transverse aortic constriction (TAC)-induced pressure overload in male C57BL/6J mice. Our data show that benzene exposure had no effect on cardiac function in the Sham group; however, it significantly compromised cardiac function as depicted by a significant decrease in fractional shortening and ejection fraction, as compared with TAC/Air-exposed mice. RNA-seq analysis of the cardiac tissue from the TAC/benzene-exposed mice showed a significant increase in several genes associated with adhesion molecules, cell-cell adhesion, inflammation, and stress response. In particular, neutrophils were implicated in our unbiased analyses. Indeed, immunofluorescence studies showed that TAC/benzene exposure promotes infiltration of CD11b+/S100A8+/myeloperoxidase+-positive neutrophils in the hearts by 3-fold. In vitro, the benzene metabolites, hydroquinone, and catechol, induced the expression of P-selectin in cardiac microvascular endothelial cells by 5-fold and increased the adhesion of neutrophils to these endothelial cells by 1.5- to 2.0-fold. Benzene metabolite-induced adhesion of neutrophils to the endothelial cells was attenuated by anti-P-selectin antibody. Together, these data suggest that benzene exacerbates heart failure by promoting endothelial activation and neutrophil recruitment.

Cardiac PANK1 deletion exacerbates ventricular dysfunction during pressure overload.

Coenzyme A (CoA) is an essential cofactor required for intermediary metabolism. Perturbations in homeostasis of CoA have been implicated in various pathologies; however, whether CoA homeostasis is changed and the extent to which CoA levels contribute to ventricular function and remodeling during pressure overload has not been explored. In this study, we sought to assess changes in CoA biosynthetic pathway during pressure overload and determine the impact of limiting CoA on cardiac function. We limited cardiac CoA levels by deleting the rate-limiting enzyme in CoA biosynthesis, pantothenate kinase 1 (Pank1). We found that constitutive, cardiomyocyte-specific Pank1 deletion (cmPank1-/-) significantly reduced PANK1 mRNA, PANK1 protein, and CoA levels compared with Pank1-sufficient littermates (cmPank1+/+) but exerted no obvious deleterious impact on the mice at baseline. We then subjected both groups of mice to pressure overload-induced heart failure. Interestingly, there was more ventricular dilation in cmPank1-/- during the pressure overload. To explore potential mechanisms contributing to this phenotype, we performed transcriptomic profiling, which suggested a role for Pank1 in regulating fibrotic and metabolic processes during the pressure overload. Indeed, Pank1 deletion exacerbated cardiac fibrosis following pressure overload. Because we were interested in the possibility of early metabolic impacts in response to pressure overload, we performed untargeted metabolomics, which indicated significant changes to metabolites involved in fatty acid and ketone metabolism, among other pathways. Collectively, our study underscores the role of elevated CoA levels in supporting fatty acid and ketone body oxidation, which may be more important than CoA-driven, enzyme-independent acetylation in the failing heart.NEW & NOTEWORTHY Changes in CoA homeostasis have been implicated in a variety of metabolic diseases; however, the extent to which changes in CoA homeostasis impacts remodeling has not been explored. We show that limiting cardiac CoA levels via PANK deletion exacerbated ventricular remodeling during pressure overload. Our results suggest that metabolic alterations, rather than structural alterations, associated with Pank1 deletion may underlie the exacerbated cardiac phenotype during pressure overload.

What do the potential recipients of disclosure of OSA say? Perspectives from adolescent residents in Scotland and Chile.

BACKGROUND: With the increase in internet use, new forms of child victimization like Online Sexual Abuse (OSA) have emerged. Children and adolescents rarely disclose these incidents and most disclosure happens around peers. OBJECTIVE: This research addresses the perspective of adolescents (not victims of OSA), potential recipients of the disclosure, within the context of disclosure of OSA committed by either adult or peer perpetrators. METHODS: The study was performed in two stages. We interviewed adolescents in Scotland and then conducted focus groups with adolescents from Chile. PARTICIPANTS AND SETTING: 51 adolescents (6 from Scotland and 45 from Chile) aged 15-20 years participated. RESULTS: Despite differences in age and cultural contexts, there were similarities in responses. Obstacles of disclosure included lack of clarity of OSA, prior levels of personal vulnerability, and gender factors (stereotypes and stigmatization). On the other hand, the disclosure process would be easier for adolescents with more personal resources (e.g. self-confidence) and when they have a supportive social environment, which includes parents, but especially peers. CONCLUSION: Disclosure of OSA is considered similar to the disclosure of offline sexual abuse. However, differences such as a lack of clarity regarding the boundaries of the relationships on the Internet, and presence of a generational gap between adolescents and their parents or tutors in the use of internet makes early disclosure of OSA highly challenging. Plans to facilitate disclosure should consider different components: behavioral (risky behaviors), emotional (feelings of fear and shame) and cognitive (lack of information, self-blame, stigma). This should be focused on adolescents, potential recipients of disclosure (parents, authorities and peers) and society, where the prejudices and practices that prevent disclosure begin.

Exploring relatives' perceptions of participation, ethics, and communication in a patient-driven study for hereditary cancer variant reclassification.

Effective communication of genetic information within families depends on several factors. Few studies explore intra-familial communication of variant of uncertain significance (VUS) results or active collaboration between family members to classify VUS. Our qualitative study aimed to describe the experiences of individuals asked by family members to participate in the FindMyVariant study, a patient-driven family study which aimed to reclassify a clinically identified familial VUS in a hereditary cancer gene. We collected feedback from 56 individuals from 21 different families through phone interviews and written correspondence, transcribed the interviews, and performed thematic analysis on all text. We describe themes from three main topics: participation, ethical considerations, and study impacts. Participation in the FindMyVariant study, defined as returning a sample for targeted genotyping, was motivated by convenience and a desire to help the family, oneself, and science. Relatives were generally responsive to invitations to participate in FindMyVariant from another family member. Those who declined to participate did so due to concerns about research program confidentiality rather than family dynamics. No major ethical issues arose in response to the patient-driven study structure, and no major changes in stress and anxiety, medical care, or behavior occurred. Participation in patient-driven familial VUS classification studies has a neutral or positive impact on family health communication. While it is important to design studies to minimize familial coercion, intra-familial confidentiality breaches, and misinterpretation of genetic results, these were not major concerns among relatives in this study. Clinicians and laboratories may consider encouraging familial communication about genetic variants using family members as liaisons.

Patient goals, motivations, and attitudes in a patient-driven variant reclassification study.

Family studies to reclassify clinically ascertained variants of uncertain significance (VUS) can impact risk assessment, medical management, and psychological outcomes for patients and their families. There are limited avenues for patients and their families to actively participate in VUS reclassification, and access to family studies at most commercial laboratories is restricted by multiple factors. To explore patient attitudes about participation in family studies for VUS reclassification, we conducted semistructured pre- and post-participation telephone interviews with 38 participants in a family-based VUS reclassification study that utilized a patient-driven approach for family ascertainment and recruitment. Participants had VUS from multigene panel testing performed at multiple clinical laboratories for cancer or other disease risk. Inductive thematic analysis of transcribed interviews highlighted four major themes: (a) Participants' study goals were driven by the desire to resolve uncertainty related to the VUS, (b) Participants had mixed reactions to the VUS reclassification outcomes of the study, (c) Personal, public, and familial knowledge increased through study participation and (d) Participants used study participation to actively cope with the uncertainty of a VUS. As personalized genomic medicine becomes more prevalent, clinicians, clinical laboratories, and researchers could consider creating more opportunities for active partnership with patients and families, who are motivated to contribute data to familial VUS studies.

Experiences of patients seeking to participate in variant of uncertain significance reclassification research.

Patients' understanding of a genetic variant of unknown clinical significance (VUS) is likely to influence beliefs about risk implications, consequent medical decisions, and other actions such as involvement in research. We interviewed 26 self-selected participants with a clinically identified VUS before they enrolled into a VUS reclassification study. Semi-structured interviews addressed topics including motivation to get genetic test, experience with the VUS result, affective responses to receiving VUS, and perceived effect of VUS and reclassification on medical care. We found that family and personal history of disease were the most prevalent motivators for getting a genetic test. Participants demonstrated mixed understanding of VUS. Most expressed negative effect on learning of their VUS result and uncertainty about its impact on clinical management. Most expected reclassification efforts to benefit their family members but not themselves. Some expressed distrust of their providers following a VUS result. Participation in the VUS reclassification study appeared to be motivated by four factors for patients with VUS-negative effect about VUS, uncertainty about its impact on clinical management, concern for family members' well-being, and to advance science. Perhaps the direct acknowledgement and appraisal of uncertainty as a means of coping was missing in some pre-test counseling experienced by our participants and thus they were not psychologically prepared for atypical VUS results. The finding of VUS-induced provider distrust suggests a need for careful consideration of appropriate pre- and post-test counseling about VUS.

Outcomes of 92 patient-driven family studies for reclassification of variants of uncertain significance.

PURPOSE: Family studies are an important but underreported source of information for reclassification of variants of uncertain significance (VUS). We evaluated outcomes of a patient-driven framework that offered familial VUS reclassification analysis to any adult with any clinically ascertained VUS from any laboratory in the United States. METHODS: With guidance from FindMyVariant.org, participants recruited their own relatives for study participation. We genotyped relatives, calculated quantitative cosegregation likelihood ratios, and evaluated variant classifications using Tavtigian's unified framework for Bayesian analysis with American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) criteria. We report participation and VUS reclassification rates from the 50 families enrolled for at least one year and reclassification results for 112 variants from the larger 92-family cohort. RESULTS: For the 50-family cohort, 6.7 relatives per family were invited to participate and 67% of relatives returned samples for genotyping. Sixty-one percent of VUS were reclassified, 84% of which were classified as benign or likely benign. Genotyping relatives identified a de novo variant, phase variants, and relatives with phenotypes highly specific for or incompatible with specific classifications. CONCLUSIONS: Motivated families can contribute to successful VUS reclassification at substantially higher rates than those previously published. Clinical laboratories could consider offering family studies to all patients with VUS.

Family Studies for Classification of Variants of Uncertain Classification: Current Laboratory Clinical Practice and a New Web-Based Educational Tool.

Multi-gene cancer panels often identify variants of uncertain clinical significance (VUS) that pose a challenge to health care providers in managing a patient's cancer risk. Family segregation analysis can yield powerful data to re-classify a VUS (as either benign or pathogenic). However, financial and personnel resources to coordinate these studies are limited. In an informal assessment we found that family studies for variant classification are done by most clinical genetics laboratories that offer hereditary cancer panel testing. The process for family studies differs substantially across laboratories. One near universal limitation is that families usually have too few individuals for an informative co-segregation analysis. A unique and potential resource-saving approach is to engage patients and their families in expanding their own pedigrees for segregation analysis of their VUS. We describe a novel public educational tool ( FindMyVariant.org ) designed to inform patients and genetic counselors about strategies to improve the probability of variant classification using familial segregation. While the web tool is designed to be useful for any gene, the project was primarily focused on VUS's returned in cancer risk genes. FindMyVariant.org is a resource for genetic providers to offer motivated families who are willing to gather information about their family relationships and history. Working alongside clinical or research genetic laboratories, the information they collect may help reclassify their VUS using segregation analysis.

Detecting the effects of Fabry disease in the adult human brain with diffusion tensor imaging and fast bound-pool fraction imaging.

BACKGROUND: To identify quantitative MRI parameters associated with diffusion tensor imaging (DTI) and fast bound-pool fraction imaging (FBFI) that may detect alterations in gray matter and/or white matter in adults with Fabry disease, a lysosomal storage disorder. MATERIALS AND METHODS: Twelve healthy controls (mean age ± standard deviation: 48.0 ± 12.4 years) and 10 participants with Fabry disease (46.7 ± 12.9 years) were imaged at 3.0 Tesla. Whole-brain parametric maps of diffusion tensor metrics (apparent diffusion coefficient [ADC] and fractional anisotropy [FA]) and the bound-pool fraction (f) were acquired. Mean voxel values of parametric maps from regions-of-interest within gray and white matter structures were compared between cases and controls using the independent t-test. Spearman's rho was used to identify associations between parametric maps and age. RESULTS: Compared with controls, the left thalamus of Fabry participants had an increase in FA (0.29 ± 0.02 versus 0.33 ± 0.05, respectively; P = 0.030) and a trend toward an increase in ADC (0.73 ± 00.02 versus 0.76 ± 0.03 µm(2) /s, respectively; P = 0.082). The left posterior white matter demonstrated a reduction in f (10.45 ± 0.37 versus 9.00 ± 1.84%, respectively; P = 0.035), an increase in ADC (0.78 ± 0.04 versus 0.94 ± 0.19 µm(2) /s, respectively; P = 0.024), and a trend toward a reduction in FA (0.42 ± 0.07 versus 0.36 ± 0.08, respectively; P = 0.052). Among all parameters, only f measured in the left posterior white matter was significantly associated with age in Fabry participants (rho = -0.71; P = 0.022). CONCLUSION: Parameters derived from DTI and FBFI detect Fabry-related changes in the adult human brain, particularly in the posterior white matter where reductions in myelin density as measured by FBFI appear age related.