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Long term high altitude exposure is known to cause tissue hypoxia and exposure of fetuses as well as adults to rarefied environments increases morbidity and mortality. In particular, hypoxia can cause developmental abnormalities in the fetal pulmonary vasculature and contribute to pulmonary arterial hypertension in the adult. β2 adrenergic receptor (β‐AR) agonists are a major treatment for asthma, however far less is known about their role in pulmonary arterial function. Even still, previous evidence illustrates that β‐AR stimulation holds promise for the treatment of pulmonary arterial hypertension. Other evidence illustrates that β‐AR stimulation modulates the activity of Ca2+‐activated K+ channels (KCa), which are important mediators of pulmonary vasorelaxation. Dysregulation of KCa may contribute to chronic hypoxia induced pulmonary hypertension and β‐AR signaling may be involved in the process. In these studies we tested the hypothesis that β‐AR ‐ mediated pulmonary arterial vasodilation may be preserved following long term high altitude hypoxia due to dependency on KCa channels. This hypothesis was addressed in isolated pulmonary arteries from adult or fetal sheep that gestated at 700 meters (normoxic) or 3,801 meters for 110+ days (hypoxic). Myography was performed on pulmonary arterial rings to evaluate the vasorelaxation in response to the β‐AR agonist isoproterenol (ISO) and the methylxanthine phosphodiesterase inhibitor, IBMX. ISO‐mediated relaxation was preserved following hypoxia in fetal sheep and relaxation was greater in arteries from adult hypoxic animals relative to fetuses. Inhibition of BKCa with TEA blunted ISO‐mediated vasorelaxation in fetal normoxic and adult hypoxic arteries. IBMX caused a dose dependent relaxation in arteries from all groups and TEA did not influence this effect. Overall, these studies provide evidence that β‐AR stimulated pathways cause pulmonary arterial vasodilation, but with varying reliance on BKCa activation. Targeting β‐AR signaling pathways could therefore be therapeutically significant and functional alterations in the pathways may contribute to the development of disease.Support or Funding InformationThis material is based upon work supported by NIH HD‐069746, P01HD083132, and P20MD006988. MA and BP were Walter E Macpherson Medical Student Summer Research Fellows while AV was an Undergraduate Summer Research Fellow through the Center for Health Disparities and Molecular Mechanisms at Loma Linda University.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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Pulmonary vein thrombosis (PVT) is an uncommon but often lethal disease with non-specific manifestations. Herein, we present a case of an elderly woman with a past medical history significant for limited-stage pelvic myxofibrosarcoma (MFS), who was admitted with subacute weakness and worsening dyspnea. Over the course of hospitalization, CT angiography was performed, which demonstrated a filling defect in the inferior left pulmonary vein consistent with PVT, in addition to evidence of widespread metastatic disease. The patient was offered therapeutic anticoagulation, but given the extent of her metastasis, the patient opted to transition to comfort care and pursued hospice care. This case serves as a unique presentation of a rare disease process associated with widespread metastatic MFS, illustrating the need for early recognition and treatment.

Background We sought risk factors for replacement of the aortic valve with or without the root (AVR/root) in the setting of acute type A aortic dissection (ATAD) repair. Methods All ATAD repairs at our institution from January 2005 to June 2018 were reviewed. Baseline characteristics were recorded. For patients with aortic valve preservation, we documented the degree of aortic insufficiency (AI) postoperatively and on subsequent echocardiograms when available. Logistic regression was used to determine the association between preoperative characteristics and the odds ratio of AVR/root. Results 206 patients underwent repair of ATAD. Thirty-four were excluded for no documented AI grading. Forty-six underwent AVR/root during repair of the ATAD (including 40 root replacements). Of 126 that did not undergo AVR/root, 42 (33.33%) had follow-up echocardiograms at a median of 68 months postoperatively, 2 required reintervention for valve insufficiency. An increase in the degree of AI, bicuspid valve morphology, size of the aortic root, and connective tissue disorder was significantly associated with increased risk of AVR/root. Of 130 patients without connective tissue disorder, bicuspid aortic valve, aortic root aneurysm or intimal root tear, the rate of valve preservation was 65/65 (100%), 25/29 (86.2%), and 22/40 (55%) for those presenting with mild, moderate, and severe AI, respectively. Conclusion The degree of preoperative AI, bicuspid valve morphology, size of the aortic root, and connective tissue disorder significantly correlate with the failure of aortic valve preservation in patients with ATAD. The vast majority of tricuspid valves in patients without connective tissue disorder or aortic root pathology can be salvaged.