Ana Isabel Fernández

Background and Aims: Modern genetic testing in hypertrophic cardiomyopathy (HCM) includes newly described HCM-associated genes and full intronic regions of certain classic sarcomeric genes. This study evaluated genetic retesting in HCM patients with a prior negative test and identified predictors of a positive result to guide retesting. Methods: This multicentre study included patients with HCM who previously had negative next-generation sequencing (NGS)-based genetic testing at four centres. Subjects were retested using an updated NGS-based HCM panel. Results: Of 508 retested HCM patients (median age 70 years; 66.9% male; median maximal left ventricular wall thickness 18 mm; median interval from initial genetic test 6.6 years), 46 (9%) had 48 HCM-related variants: 14 in new HCM-associated genes, 3 in deep intronic MYBPC3 regions, 18 intermediate-effect variants, and 13 (8 reclassified) in classic HCM-associated genes. In multivariable analysis, the presence of late gadolinium enhancement (LGE) [odds ratio (OR) 3.52; 95% confidence interval (CI) 1.38–10.25], the Mayo HCM score (OR 1.46 per 1 point increase; 95% CI 1.08–2.01), and the Toronto HCM score (OR 1.18 per 1 point increase; 95% CI 1.08–1.30) were independent predictors of detecting HCM-related variants at retesting. The diagnostic yields in patients with LGE and a high Toronto score (≥13 points), and with LGE and a high Mayo score (≥4 points), were 80% and 50%, respectively. Conclusions: In patients with HCM and prior negative genetic testing, retesting identified HCM-related variants in 9% of individuals, allowing counselling and risk stratification. Late gadolinium enhancement, combined with the Mayo and Toronto scores, may be used to guide which patients should be prioritized for genetic retesting.

BACKGROUND: PPA2 (pyrophosphatase 2) deficiency is a relatively newly recognized condition caused by biallelic variants in the PPA2 gene. The gene encodes the mitochondrial enzyme PPA2, involved in the production of orthophosphate in the mitochondrial matrix. Affected individuals typically present with sudden cardiac death or acute heart failure following common viral illnesses in infants and toddlers, or following exposure to small amounts of alcohol as teenagers. The condition has a high mortality rate in these situations. Here, we explore the clinical presentations and current management of these patients with a view to guiding future emergency clinical management of cases. METHODS: Case records from published and unpublished affected individuals diagnosed with PPA2 deficiency were compiled in a retrospective cohort study of genotypes, phenotypes and clinical management protocols in individuals with biallelic (likely) pathogenic PPA2 variants. RESULTS: We collated 93 affected individuals from 53 families, 14 of which have not previously been reported. Patient presentation is invariably acute, often associated with fatigue, vomiting, seizures and collapse. Generally, presenting individuals received standard emergency management with cardiopulmonary resuscitation and appropriate management of arrhythmia, and here we present compiled clinical management protocols for emergency and ongoing treatment of PPA2-deficient patients. A pronounced inheritance rate of pathogenic alleles from carrier parents is noted, and further research is warranted to confirm and investigate any selective advantage for gametes carrying pathogenic PPA2 variants. CONCLUSIONS: PPA2 deficiency has a high mortality rate following exposure to common childhood viruses in children around and under the age of 3 and in teenagers exposed to ethanol. We have presented current therapeutic approaches gathered from a worldwide survey of clinicians treating their patients, possible pathogenic mechanisms and inheritance peculiarities of the condition and provide a comprehensive review of the current recommendations surrounding patients’ clinical management.

To delve deeper into the molecular mechanisms underlying pulmonary hypertension secondary to left heart disease (PH-LHD), an essential step toward developing a comprehensive classification, reliable biomarkers and targeted therapies. In this study, we analyzed the whole transcriptome (mRNA and microRNA) of a unique cohort of patients with persistent PH due to valvular heart disease (PH-VHD) to identify biological pathways associated with disease prognosis. The analysis was performed using the well-characterized SIOVAC (Sildenafil for Improving Outcomes after Valvular Correction) clinical trial cohort. We included 116 patients with demonstrated PH-LHD after valvular correction, and 30 VHD patients with no or mild PH (Control). The comparison between PH-LHD patients and controls of the whole blood transcriptome identified 3,217 differentially expressed genes. Unsupervised clustering in PH-VHD patients revealed three clusters (K1–K3), with K1 showing significantly worse 84-month survival (p = 0.017) despite no clinical or hemodynamic differences among clusters. Enrichment analysis identified 173 significantly altered canonical pathways, involved in inflammatory and stress-related networks (e.g., Granzyme A, IL-15, JAK/STAT, HIF1α) and inhibition of metabolic and translational processes (e.g., oxidative phosphorylation, EIF2). Circulating microRNA analysis identified 97 differentially expressed microRNAs; notably, BMPR2 was regulated by 22 of these and demonstrated significant downregulation of its functional isoform A in K1 patients. In conclusion PH-VHD transcriptomic signature identifies a cluster of patients associated with higher risk of mortality characterized by immune overactivation and a mitochondrial metabolic shift, with BMPR2 emerging as a key metabolic target.

Pulmonary hypertension (PH) associated with left heart disease (PH-LHD) represents a major health issue worldwide, accounting for nearly 75% of cases of PH. PH-LHD eventually develops in more than half of patients with heart failure and confers poor prognosis. It is recognised that targeted therapies are lacking partially because the underlying molecular mechanisms remain poorly understood [1, 2].

BMPR2 is widely known to be key in the pathobiology of pulmonary arterial hypertension. Recently, data regarding pulmonary hypertension (PH) secondary to left-heart disease (LHD) have focused on inflammatory and proliferative pathways rather than classic hemodynamic scope but BMPR2 role is yet to be determined. In the current study, we assessed BMPR2 and its regulatory factor, SRSF2, in patients with PH due to valvular heart disease (VHD). Blood samples from patients included in the Sildenafil for Improving Outcomes after Valvular Correction (SIOVAC) clinical trial were analysed. The study involved PH-VHD patients with combined pre-and postcapillary PH, isolated postcapillary PH, control patients without PH and healthy subjects. We sequenced the BMPR2 exons, measured BMPR2 A-isoform expression and analysed SRSF2 gene expression levels in blood samples. Our results demonstrate that BMPR2 A-isoform levels are reduced in patients with PH-VHD compared to controls and, even more, healthy subjects. Furthermore, BMPR2 A-isoform expression showed meaningful prognostic value among PH-VHD patients. Notably, whereas pathogenic gene variants were ruled out, SRSF2 was indeed associated with BMPR2 A-isoform differential expression. To the best of our knowledge, this is the first study demonstrating the involvement of BMPR2 gene expression in PH-LHD patients, supports BMPR2 A-isoform as a potential prognosis biomarker and this pathway as a therapeutic target.

A comprehensive understanding of gut microbiota in a clearly defined group of healthy individuals is essential when making meaningful comparisons with various diseases. The Mediterranean diet (MD), renowned for its potential health benefits, and the influence of adherence thereto on gut microbiota have become a focus of research. Our aim was to elucidate the impact of adherence to the MD on gut microbiota composition in a well-defined cohort. In this prospective study, healthy volunteers completed a questionnaire to provide demographic data, medical history, and dietary intake. Adherence was evaluated using the Med-DQI. The V4 region of the 16S rRNA gene was sequenced. Analysis of sequencing data and statistical analysis were performed using MOTHUR software and R. The study included 60 patients (51.7% females). Adherence correlated with alpha diversity, and higher values were recorded in good adherers. Good adherers had a higher abundance of Paraprevotella and Bacteroides (p < 0.001). Alpha diversity correlated inversely with fat intake and positively with non-starch polysaccharides (NSPs). Evenness correlated inversely with red meat intake and positively with NSPs. Predicted functional analysis highlighted metabolic pathway differences based on adherence to the MD. In conclusion, our study adds useful information on the relationship between the MD and the gut microbiome.

BACKGROUND: Twitch-independent tension has been demonstrated in cardiomyocytes, but its role in heart failure (HF) is unclear. We aimed to address twitch-independent tension as a source of diastolic dysfunction by isolating the effects of chamber resting tone (RT) from impaired relaxation and stiffness. METHODS: We invasively monitored pressure-volume data during cardiopulmonary exercise in 20 patients with hypertrophic cardiomyopathy, 17 control subjects, and 35 patients with HF with preserved ejection fraction. To measure RT, we developed a new method to fit continuous pressure-volume measurements, and first validated it in a computational model of loss of cMyBP-C (myosin binding protein-C). RESULTS: In hypertrophic cardiomyopathy, RT (estimated marginal mean [95% CI]) was 3.4 (0.4–6.4) mm Hg, increasing to 18.5 (15.5–21.5) mm Hg with exercise ( P P =0.02) and with pulmonary wedge pressure but following different slopes at rest and during exercise (R ² =0.49; P <0.001). In controls, RT was 0.0 mm Hg and 1.2 (0.3–2.8) mm Hg in HF with preserved ejection fraction patients and was also exacerbated by exercise. In silico, RT increased in parallel to the loss of cMyBP-C function and correlated with twitch-independent myofilament tension (R=0.997). CONCLUSIONS: Augmented RT is the major cause of LV diastolic chamber dysfunction in hypertrophic cardiomyopathy and HF with preserved ejection fraction. RT transients determine diastolic pressures, pulmonary pressures, and functional capacity to a greater extent than relaxation and stiffness abnormalities. These findings support antimyosin agents for treating HF.