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BACKGROUND: Pulmonary hypertension (PH) represents an important phenotype in heart failure with preserved ejection fraction (HFpEF). However, management of PH-HFpEF is challenging because mechanisms involved in the regulation of PH-HFpEF remain unclear. METHODS: We used a mass spectrometry-based comparative plasma proteomics approach as a sensitive and comprehensive hypothesis-generating discovery technique to profile proteins in patients with PH-HFpEF and control subjects. We then validated and investigated the role of one of the identified proteins using in vitro cell cultures, in vivo animal models, and independent cohort of human samples. RESULTS: Plasma proteomics identified high protein abundance levels of B2M (β2-microglobulin) in patients with PH-HFpEF. Interestingly, both circulating and skeletal muscle levels of B2M were increased in mice with skeletal muscle SIRT3 (sirtuin-3) deficiency or high-fat diet-induced PH-HFpEF. Plasma and muscle biopsies from a validation cohort of PH-HFpEF patients were found to have increased B2M levels, which positively correlated with disease severity, especially pulmonary capillary wedge pressure and right atrial pressure at rest. Not only did the administration of exogenous B2M promote migration/proliferation in pulmonary arterial vascular endothelial cells but it also increased PCNA (proliferating cell nuclear antigen) expression and cell proliferation in pulmonary arterial vascular smooth muscle cells. Finally, B2m deletion improved glucose intolerance, reduced pulmonary vascular remodeling, lowered PH, and attenuated RV hypertrophy in mice with high-fat diet-induced PH-HFpEF. CONCLUSIONS: Patients with PH-HFpEF display higher circulating and skeletal muscle expression levels of B2M, the magnitude of which correlates with disease severity. Our findings also reveal a previously unknown pathogenic role of B2M in the regulation of pulmonary vascular proliferative remodeling and PH-HFpEF. These data suggest that circulating and skeletal muscle B2M can be promising targets for the management of PH-HFpEF.

Women with pulmonary arterial hypertension (PAH) exhibit better right ventricular (RV) function and survival than men; however, the underlying mechanisms are unknown. We hypothesized that 17β-estradiol (E2), through estrogen receptor α (ER-α), attenuates PAH-induced RV failure (RVF) by upregulating the procontractile and prosurvival peptide apelin via a BMPR2-dependent mechanism. We found that ER-α and apelin expression were decreased in RV homogenates from patients with RVF and from rats with maladaptive (but not adaptive) RV remodeling. RV cardiomyocyte apelin abundance increased in vivo or in vitro after treatment with E2 or ER-α agonist. Studies employing ER-α-null or ER-β-null mice, ER-α loss-of-function mutant rats, or siRNA demonstrated that ER-α is necessary for E2 to upregulate RV apelin. E2 and ER-α increased BMPR2 in pulmonary hypertension RVs and in isolated RV cardiomyocytes, associated with ER-α binding to the Bmpr2 promoter. BMPR2 is required for E2-mediated increases in apelin abundance, and both BMPR2 and apelin are necessary for E2 to exert RV-protective effects. E2 or ER-α agonist rescued monocrotaline pulmonary hypertension and restored RV apelin and BMPR2. We identified what we believe to be a novel cardioprotective E2/ER-α/BMPR2/apelin axis in the RV. Harnessing this axis may lead to novel RV-targeted therapies for PAH patients of either sex.

ObjectivePulmonary hypertension (PH) due to left heart disease (group 2), especially in the setting of heart failure with preserved ejection fraction (HFpEF), is the most common cause of PH worldwide; however, at present, there is no proven effective therapy available for its treatment. PH-HFpEF is associated with insulin resistance and features of metabolic syndrome. The stable prostacyclin analog, treprostinil, is an effective and widely used Food and Drug Administration-approved drug for the treatment of pulmonary arterial hypertension. While the effect of treprostinil on metabolic syndrome is unknown, a recent study suggests that the prostacyclin analog beraprost can improve glucose intolerance and insulin sensitivity. We sought to evaluate the effectiveness of treprostinil in the treatment of metabolic syndrome-associated PH-HFpEF. Approach and Results: Treprostinil treatment was given to mice with mild metabolic syndrome-associated PH-HFpEF induced by high-fat diet and to SU5416/obese ZSF1 rats, a model created by the treatment of rats with a more profound metabolic syndrome due to double leptin receptor defect (obese ZSF1) with a vascular endothelial growth factor receptor blocker SU5416. In high-fat diet-exposed mice, chronic treatment with treprostinil reduced hyperglycemia and pulmonary hypertension. In SU5416/Obese ZSF1 rats, treprostinil improved hyperglycemia with similar efficacy to that of metformin (a first-line drug for type 2 diabetes mellitus); the glucose-lowering effect of treprostinil was further potentiated by the combined treatment with metformin. Early treatment with treprostinil in SU5416/Obese ZSF1 rats lowered pulmonary pressures, and a late treatment with treprostinil together with metformin improved pulmonary artery acceleration time to ejection time ratio and tricuspid annular plane systolic excursion with AMPK (AMP-activated protein kinase) activation in skeletal muscle and the right ventricle.ConclusionsOur data suggest a potential use of treprostinil as an early treatment for mild metabolic syndrome-associated PH-HFpEF and that combined treatment with treprostinil and metformin may improve hyperglycemia and cardiac function in a more severe disease.

Herein, we report an euselachian assemblage from the late Campanian Bearpaw Formation recovered from southern Alberta, Canada. This small yet uniquely diverse fauna includes the northernmost occurrences of Paraorthacodus andersoni, Squalus worlandensis, Odontaspis aculeatus, and Archaeotriakis ornatus within the Western Interior Seaway. It also constitutes the first record of P. andersoni, S. worlandensis, and A. ornatus from Canadian deposits. Moreover, we report the stratigraphically youngest record of Cretoxyrhina mantelli. This assemblage is unique in that all the identifiable euselachian species are either pelagic or benthopelagic but not benthic. This is in stark contrast to the batoid-rich euselachian assemblage of the Lethbridge Coal Zone that immediately underlies the Bearpaw Formation in southern Alberta. We attribute this difference to dysoxic bottom waters during the deposition of the formation, rather than to sampling bias. [ABSTRACT FROM AUTHOR]

The fossil bearing beds of Moghra, Egypt, have been well known for over 100 years, but the ichthyofaunas have not been examined since the early 1900s. Moghra, on the northern rim of the Qattara Depression, preserves early Miocene (18-17 Ma) fluvio-marine sediments with fossils of wood, invertebrates and vertebrates. The Moghra site is faunally similar to the Libyan Gebel Zelten site, at least in terms of the fossil mammals. The fossil-bearing localities in the Moghra Formation number about 40 and span a distance of about 50 km. There is likely more than one depositional environment represented. The fish previously reported from Moghra include two teleosts, Synodontis (Mochokidae) and Lates (Latidae), as well as the elasmobranchs, Pristis (Pristidae), Myliobatis (Myliobatidae) and Sphyrna (Sphyrnidae). Several more recent expeditions to the Moghra localities recovered abundant selachian remains. This rich assemblage included species from the genera Carcharias (Odontaspididae), Megaselachus (Otodontidae), Cosmopolitodus (Lamnidae), Hemipristis (Hemigaleidae), Galeocerdo and Carcharhinus (Carcharhinidae), Myliobatis (Myliobatidae), Pteromylaeus (Myliobatidae) and Aetobatis (Myliobatidae). With the additional taxa from these collections, we can build a more comprehensive understanding of the Moghra fauna and environment. [ABSTRACT FROM AUTHOR]