Emerging pharmacotherapies for the treatment of pulmonary arterial hypertension.

INTRODUCTION: Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease. Approved treatment options currently primarily target abnormal cell signaling pathways involved in vasoconstriction and proliferation, such as those mediated by prostacyclin, cyclic guanosine monophosphate, and endothelin. AREAS COVERED: Recent advancements have led to new applications and modes of delivery of currently approved PAH medications. At the same time, novel drugs targeting specific molecular pathways involved in PAH pathogenesis have been developed and are being investigated in clinical trials. This review summarizes investigational drug trials for PAH gathered from a comprehensive search using PubMed and ClinicalTrials.gov between 2003 and 2023. It includes both currently approved medications studied at different doses or new administration forms and experimental drugs that have not yet been approved. EXPERT OPINION: Approved treatments for PAH target imbalances in pulmonary vasoactive pathways that work primarily on enhancing pulmonary vasodilation with less salient effects on pulmonary vascular remodeling. The advent of more locally acting inhaled medications offers additional therapeutic options that may improve the ease of drug delivery and reduce adverse systemic effects. The more recent emphasis on developing and applying therapeutics that directly impact the aberrant signaling pathways implicated in PAH appears more likely to advance the treatment of this devastating disease.

Perceptions and Use of E-cigarettes among Young Adults with Cystic Fibrosis: An Observational Study.

While smoking prevalence has decreased among the general population, the use of electronic cigarettes (E- cigarettes) has risen significantly and can cause significant lung injury. We sought to determine if persons with cystic fibrosis (PwCF) have similar rates of E-cigarette use as compared with age-matched peers, and to understand perceptions of E-cigarette safety through a survey-based study. A total of 29 PwCF and 26 age-matched control patients participated in this study. There was no significant difference between PwCF and control patients regarding perceptions of the negative impact of E-cigarette use on one's health. Overall, both PwCF and control patients reported a good quality of life. PwCF were equally likely to identify E-cigarettes as harmful to one's lung health as healthy controls but were significantly more likely to have heard of EVALI. While small, our study has demonstrated the need for further education of both PwCF and healthy young adults.

Integrating Primary Care into the Management of Cystic Fibrosis.

Over the last 50 years, cystic fibrosis has radically transformed from a fatal disease of infancy to a chronic disease of adulthood. By 2025 it is estimated that 70% of individuals with cystic fibrosis (iwCF) will be cared for in adult clinics. We believe the role of a dedicated primary care provider (PCP) for preventative care will be crucial for the longevity of iwCF. There are various models for incorporating primary care medicine into CF management, but no universally accepted standard exists. Ideally, the PCP and pulmonologist practice in a patientcentered medical home, given the growing evidence that these care models are associated with improved quality-of-life measures, mental health, and disease-specific outcomes. To improve engagement with primary care in CF, there needs to be a shift in education at the undergraduate medical education and provider training levels. Increasing the knowledge of CF-related illness is vital in fostering a close relationship between the PCP and their patient. To meet this need, primary care doctors will need tools and practical experiences in managing this rare condition. This can start being addressed by providing ample opportunities for the inclusion of PCPs into subspecialty clinics and through engagement with community providers through readily available didactics, seminars, and open lines of communication. As PCPs and CF clinicians, we feel that shifting the domain of preventative care to the expertise of a primary care physician will allow for a more CF-specific focus in subspecialty clinics and help prevent these vital health maintenance tasks from being overlooked, altogether advancing the health and well-being of iwCF.

Challenges to advance care planning among multidisciplinary health professionals in China.

BACKGROUND: Advance care planning (ACP) is a critical component of quality end-of-life care. Little is known regarding the cultural influences on health professionals' attitudes toward the discussion of ACP in China. OBJECTIVE: To better understand attitudes toward ACP among Chinese healthcare professionals in China and the influence of cultural factors such as filial piety, or xiào. METHODS: A mixed methods study was used. This study reports the results of a descriptive cross-sectional survey of physicians, nurses and social workers with experience in palliative and end-of-life care. RESULTS: Some 102 completed surveys were obtained. Most Chinese health professionals had an overall positive attitude toward ACP, acknowledging that these discussions should occur. However, there was a general lack of confidence and sense of reluctance among participants to engage in ACP discussions. CONCLUSION: The lack of statistical difference between the various health professionals suggests that they all faced challenges in participating in ACP discussions. Future research should focus on the influences of cultural factors such as xiào on ACP discussion, and develop culturally sensitive strategies to facilitate these discussions in the Chinese community.

A New Murine Model for Gastrointestinal Anthrax Infection.

The scientific community has been restricted by the lack of a practical and informative animal model of gastrointestinal infection with vegetative Bacillus anthracis. We herein report the development of a murine model of gastrointestinal anthrax infection by gavage of vegetative Sterne strain of Bacillus anthracis into the complement-deficient A/J mouse strain. Mice infected in this manner developed lethal infections in a dose-dependent manner and died 30 h-5 d following gavage. Histological findings were consistent with penetration and growth of the bacilli within the intestinal villi, with subsequent dissemination into major organs including the spleen, liver, kidney and lung. Blood cultures confirmed anthrax bacteremia in all moribund animals, with approximately 1/3 showing co-infection with commensal enteric organisms. However, no evidence of immune activation was observed during infection. Time-course experiments revealed early compromise of the intestinal epithelium, characterized by villus blunting and ulceration in the ileum and jejunum. A decrease in body temperature was most predictive of near-term lethality. Antibiotic treatment of infected animals 24 h following high-dose bacterial gavage protected all animals, demonstrating the utility of this animal model in evaluating potential therapeutics.

Anthrax lethal toxin disrupts intestinal barrier function and causes systemic infections with enteric bacteria.

A variety of intestinal pathogens have virulence factors that target mitogen activated protein kinase (MAPK) signaling pathways, including Bacillus anthracis. Anthrax lethal toxin (LT) has specific proteolytic activity against the upstream regulators of MAPKs, the MAPK kinases (MKKs). Using a murine model of intoxication, we show that LT causes the dose-dependent disruption of intestinal epithelial integrity, characterized by mucosal erosion, ulceration, and bleeding. This pathology correlates with an LT-dependent blockade of intestinal crypt cell proliferation, accompanied by marked apoptosis in the villus tips. C57BL/6J mice treated with intravenous LT nearly uniformly develop systemic infections with commensal enteric organisms within 72 hours of administration. LT-dependent intestinal pathology depends upon its proteolytic activity and is partially attenuated by co-administration of broad spectrum antibiotics, indicating that it is both a cause and an effect of infection. These findings indicate that targeting of MAPK signaling pathways by anthrax LT compromises the structural integrity of the mucosal layer, serving to undermine the effectiveness of the intestinal barrier. Combined with the well-described immunosuppressive effects of LT, this disruption of the intestinal barrier provides a potential mechanism for host invasion via the enteric route, a common portal of entry during the natural infection cycle of Bacillus anthracis.

The effects of anthrax lethal toxin on host barrier function.

The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects.

Mutations in GATA2 are associated with the autosomal dominant and sporadic monocytopenia and mycobacterial infection (MonoMAC) syndrome.

The syndrome of monocytopenia, B-cell and NK-cell lymphopenia, and mycobacterial, fungal, and viral infections is associated with myelodysplasia, cytogenetic abnormalities, pulmonary alveolar proteinosis, and myeloid leukemias. Both autosomal dominant and sporadic cases occur. We identified 12 distinct mutations in GATA2 affecting 20 patients and relatives with this syndrome, including recurrent missense mutations affecting the zinc finger-2 domain (R398W and T354M), suggesting dominant interference of gene function. Four discrete insertion/deletion mutations leading to frame shifts and premature termination implicate haploinsufficiency as a possible mechanism of action as well. These mutations were found in hematopoietic and somatic tissues, and several were identified in families, indicating germline transmission. Thus, GATA2 joins RUNX1 and CEBPA not only as a familial leukemia gene but also as a cause of a complex congenital immunodeficiency that evolves over decades and combines predisposition to infection and myeloid malignancy.

Neutrophil elastase mediates pathogenic effects of anthrax lethal toxin in the murine intestinal tract.

Neutrophils isolated from BALB/c or C57BL/6 mice and treated in vitro with anthrax lethal toxin release bioactive neutrophil elastase, a proinflammatory mediator of tissue destruction. Similarly, neutrophils isolated from mice treated with anthrax lethal toxin in vivo and cultured ex vivo release greater amounts of elastase than neutrophils from vehicle-treated controls. Direct measurements from murine intestinal tissue samples demonstrate an anthrax lethal toxin-dependent increase in neutrophil elastase activity in vivo as well. These findings correlate with marked lethal toxin-induced intestinal ulceration and bleeding in neutrophil elastase(+/+) animals, but not in neutrophil elastase(-/-) animals. Moreover, neutrophil elastase(-/-) mice have a significant survival advantage over neutrophil elastase(+/+) animals following exposure to anthrax lethal toxin, thereby establishing a key role for neutrophil elastase in mediating the deleterious effects of anthrax lethal toxin.