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435 result(s) for "Vargas, Sara"
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Cystic masses of the pediatric lung: update on congenital pulmonary airway malformation and its differential diagnosis
Localized cystic lung lesions in pediatric patients encompass a spectrum of benign and rare malignant conditions that are quite distinct from cystic lung disease arising in adulthood. The majority have historically fallen under the diagnostic category of “congenital pulmonary airway malformation,” a term that has been used to denote a diverse group of diseases ranging in etiology from ectopia to bronchial atresia to mosaic oncogenic mutation or neoplasia. This article reviews the clinical characteristics, gross and histologic features, and pathogenetic underpinnings of congenital pulmonary airway malformation as well as lesions that enter its histologic differential diagnosis. In light of ongoing advances in the field, previously proposed pathology-based classification schemes are critically appraised, and a new diagnostic framework is considered.
Vascular stiffness mechanoactivates YAP/TAZ-dependent glutaminolysis to drive pulmonary hypertension
Dysregulation of vascular stiffness and cellular metabolism occurs early in pulmonary hypertension (PH). However, the mechanisms by which biophysical properties of the vascular extracellular matrix (ECM) relate to metabolic processes important in PH remain undefined. In this work, we examined cultured pulmonary vascular cells and various types of PH-diseased lung tissue and determined that ECM stiffening resulted in mechanoactivation of the transcriptional coactivators YAP and TAZ (WWTR1). YAP/TAZ activation modulated metabolic enzymes, including glutaminase (GLS1), to coordinate glutaminolysis and glycolysis. Glutaminolysis, an anaplerotic pathway, replenished aspartate for anabolic biosynthesis, which was critical for sustaining proliferation and migration within stiff ECM. In vitro, GLS1 inhibition blocked aspartate production and reprogrammed cellular proliferation pathways, while application of aspartate restored proliferation. In the monocrotaline rat model of PH, pharmacologic modulation of pulmonary vascular stiffness and YAP-dependent mechanotransduction altered glutaminolysis, pulmonary vascular proliferation, and manifestations of PH. Additionally, pharmacologic targeting of GLS1 in this model ameliorated disease progression. Notably, evaluation of simian immunodeficiency virus-infected nonhuman primates and HIV-infected subjects revealed a correlation between YAP/TAZ-GLS activation and PH. These results indicate that ECM stiffening sustains vascular cell growth and migration through YAP/TAZ-dependent glutaminolysis and anaplerosis, and thereby link mechanical stimuli to dysregulated vascular metabolism. Furthermore, this study identifies potential metabolic drug targets for therapeutic development in PH.
Belzutifan, a Potent HIF2α Inhibitor, in the Pacak–Zhuang Syndrome
The integration of genomic testing into clinical care enables the use of individualized approaches to the management of rare diseases. We describe the use of belzutifan, a potent and selective small-molecule inhibitor of the protein hypoxia-inducible factor 2α (HIF2α), in a patient with polycythemia and multiple paragangliomas (the Pacak–Zhuang syndrome). The syndrome was caused in this patient by somatic mosaicism for an activating mutation in EPAS1 . Treatment with belzutifan led to a rapid and sustained tumor response along with resolution of hypertension, headaches, and long-standing polycythemia. This case shows the application of a targeted therapy for the treatment of a patient with a rare tumor-predisposition syndrome. (Funded by the Morin Family Fund for Pediatric Cancer and Alex’s Lemonade Stand Foundation.) Pacak–Zhuang syndrome is an inherited tumor-predisposition disorder characterized by polycythemia and paragangliomas. A patient with this disorder had polycythemia, headache, hypertension, and norepinephrine-secreting paragangliomas. She had activating mutations in HIF2A . Use of belzutifan, a HIF2α inhibitor, led to paraganglioma regression, normalized hemoglobin levels, and symptom resolution.
Safety and pharmacokinetics of single, dual, and triple antiretroviral drug formulations delivered by pod-intravaginal rings designed for HIV-1 prevention: A Phase I trial
Intravaginal rings (IVRs) for HIV pre-exposure prophylaxis (PrEP) theoretically overcome some adherence concerns associated with frequent dosing that can occur with oral or vaginal film/gel regimens. An innovative pod-IVR, composed of an elastomer scaffold that can hold up to 10 polymer-coated drug cores (or \"pods\"), is distinct from other IVR designs as drug release from each pod can be controlled independently. A pod-IVR has been developed for the delivery of tenofovir (TFV) disoproxil fumarate (TDF) in combination with emtricitabine (FTC), as daily oral TDF-FTC is the only Food and Drug Administration (FDA)-approved regimen for HIV PrEP. A triple combination IVR building on this platform and delivering TDF-FTC along with the antiretroviral (ARV) agent maraviroc (MVC) also is under development. This pilot Phase I trial conducted between June 23, 2015, and July 15, 2016, evaluated the safety, pharmacokinetics (PKs), and acceptability of pod-IVRs delivering 3 different ARV regimens: 1) TDF only, 2) TDF-FTC, and 3) TDF-FTC-MVC over 7 d. The crossover, open-label portion of the trial (N = 6) consisted of 7 d of continuous TDF pod-IVR use, a wash-out phase, and 7 d of continuous TDF-FTC pod-IVR use. After a 3-mo pause to evaluate safety and PK of the TDF and TDF-FTC pod-IVRs, TDF-FTC-MVC pod-IVRs (N = 6) were evaluated over 7 d of continuous use. Safety was assessed by adverse events (AEs), colposcopy, and culture-independent analysis of the vaginal microbiome (VMB). Drug and drug metabolite concentrations in plasma, cervicovaginal fluids (CVFs), cervicovaginal lavages (CVLs), and vaginal tissue (VT) biopsies were determined via liquid chromatographic-tandem mass spectrometry (LC-MS/MS). Perceptibility and acceptability were assessed by surveys and interviews. Median participant age was as follows: TDF/TDF-FTC group, 26 y (range 24-35 y), 2 White, 2 Hispanic, and 2 African American; TDF-FTC-MVC group, 24.5 y (range 21-41 y), 3 White, 1 Hispanic, and 2 African American. Reported acceptability was high for all 3 products, and pod-IVR use was confirmed by residual drug levels in used IVRs. There were no serious adverse events (SAEs) during the study. There were 26 AEs reported during TDF/TDF-FTC IVR use (itching, discharge, discomfort), with no differences between TDF alone or in combination with FTC observed. In the TDF-FTC-MVC IVR group, there were 12 AEs (itching, discharge, discomfort) during IVR use regardless of attribution to study product. No epithelial disruption/thinning was seen by colposcopy, and no systematic VMB shifts were observed. Median (IQR) tenofovir diphosphate (TFV-DP) tissue concentrations of 303 (277-938) fmol/10(6) cells (TDF), 289 (110-603) fmol/10(6) cells (TDF-FTC), and 302 (177.1-823.8) fmol/10(6) cells (TDF-FTC-MVC) were sustained for 7 d, exceeding theoretical target concentrations for vaginal HIV prevention. The study's main limitations include the small sample size, short duration (7 d versus 28 d), and the lack of FTC triphosphate measurements in VT biopsies. An innovative pod-IVR delivery device with 3 different formulations delivering different regimens of ARV drugs vaginally appeared to be safe and acceptable and provided drug concentrations in CVFs and tissues exceeding concentrations achieved by highly protective oral dosing, suggesting that efficacy for vaginal HIV PrEP is achievable. These results show that an alternate, more adherence-independent, longer-acting prevention device based on the only FDA-approved PrEP combination regimen can be advanced to safety and efficacy testing. ClinicalTrials.gov NCT02431273.
The preparation phase in the multiphase optimization strategy (MOST): a systematic review and introduction of a reporting checklist
Abstract Multicomponent behavioral interventions developed using the multiphase optimization strategy (MOST) framework offer important advantages over alternative intervention development models by focusing on outcomes within constraints relevant for effective dissemination. MOST consists of three phases: preparation, optimization, and evaluation. The preparation phase is critical to establishing the foundation for the optimization and evaluation phases; thus, detailed reporting is critical to enhancing rigor and reproducibility. A systematic review of published research using the MOST framework was conducted. A structured framework was used to describe and summarize the use of MOST terminology (i.e., preparation phase and optimization objective) and the presentation of preparation work, the conceptual model, and the optimization. Fifty-eight articles were reviewed and the majority focused on either describing the methodology or presenting results of an optimization trial (n = 38, 66%). Although almost all articles identified intervention components (96%), there was considerable variability in the degree to which authors fully described other elements of MOST. In particular, there was less consistency in use of MOST terminology. Reporting on the MOST preparation phase is varied, and there is a need for increased focus on explicit articulation of key design elements and rationale of the preparation phase. The proposed checklist for reporting MOST studies would significantly advance the use of this emerging methodology and improve implementation and dissemination of MOST. Accurate reporting is essential to reproducibility and rigor of scientific trials as it ensures future research fully understands not only the methodology, but the rationale for intervention and optimization decisions. The Multiphase Optimization Strategy is a research design framework with growing implementation. There is a need for standardized reporting guidelines to enhance reproducibility and rigor; the PREP-REP checklist provides guidance for researchers.
Global and local selection acting on the pathogen Stenotrophomonas maltophilia in the human lung
Bacterial populations diversify during infection into distinct subpopulations that coexist within the human body. Yet, it is unknown to what extent subpopulations adapt to location-specific selective pressures as they migrate and evolve across space. Here we identify bacterial genes under local and global selection by testing for spatial co-occurrence of adaptive mutations. We sequence 552 genomes of the pathogen Stenotrophomonas maltophilia across 23 sites of the lungs from a patient with cystic fibrosis. We show that although genetically close isolates colocalize in space, distant lineages with distinct phenotypes separated by adaptive mutations spread throughout the lung, suggesting global selective pressures. Yet, for one gene (a distant homologue of the merC gene implicated in metal resistance), mutations arising independently in two lineages colocalize in space, providing evidence for location-specific selection. Our work presents a general framework for understanding how selection acts upon a pathogen that colonizes and evolves across the complex environment of the human body. The authors sequence the genomes of 552 bacterial isolates sampled across 23 sites of the lungs of a patient with cystic fibrosis, and identify bacterial genes under global and location-specific adaptation.
De novo mutations mediate phenotypic switching in an opportunistic human lung pathogen
Bacteria evolving within human hosts encounter selective tradeoffs that render mutations adaptive in one context and deleterious in another. Here, we report that the cystic fibrosis-associated pathogen Burkholderia dolosa overcomes in-human selective tradeoffs by acquiring successive point mutations that alternate phenotypes. We sequenced the whole genomes of 931 respiratory isolates from two recently infected cystic fibrosis patients and an epidemiologically-linked, chronically-infected patient. These isolates are contextualized using 112 historical genomes from the same outbreak strain. Within both newly infected patients, convergent mutations that disrupt O-antigen expression quickly arose, comprising 29% and 63% of their B. dolosa communities by 3 years. The selection for loss of O-antigen starkly contrasts with our previous observation of parallel O-antigen-restoring mutations after many years of chronic infection in the historical outbreak. Experimental characterization reveals that O-antigen loss increases uptake in immune cells while decreasing competitiveness in the mouse lung. We propose that the balance of these pressures, and thus whether O-antigen expression is advantageous, depends on tissue localization and infection duration. These results suggest that mutation-driven phenotypic alternation may be underestimated without dense temporal sampling, particularly for microbes with prolonged infection or colonization. Bacteria evolving within humans employ strategies to overcome trade-offs. Here, the authors report that the cystic fibrosis-associated pathogen Burkholderia dolosa alternates phenotypes in vivo by accumulating successive de novo mutations.
Systems-level regulation of microRNA networks by miR-130/301 promotes pulmonary hypertension
Development of the vascular disease pulmonary hypertension (PH) involves disparate molecular pathways that span multiple cell types. MicroRNAs (miRNAs) may coordinately regulate PH progression, but the integrative functions of miRNAs in this process have been challenging to define with conventional approaches. Here, analysis of the molecular network architecture specific to PH predicted that the miR-130/301 family is a master regulator of cellular proliferation in PH via regulation of subordinate miRNA pathways with unexpected connections to one another. In validation of this model, diseased pulmonary vessels and plasma from mammalian models and human PH subjects exhibited upregulation of miR-130/301 expression. Evaluation of pulmonary arterial endothelial cells and smooth muscle cells revealed that miR-130/301 targeted PPARγ with distinct consequences. In endothelial cells, miR-130/301 modulated apelin-miR-424/503-FGF2 signaling, while in smooth muscle cells, miR-130/301 modulated STAT3-miR-204 signaling to promote PH-associated phenotypes. In murine models, induction of miR-130/301 promoted pathogenic PH-associated effects, while miR-130/301 inhibition prevented PH pathogenesis. Together, these results provide insight into the systems-level regulation of miRNA-disease gene networks in PH with broad implications for miRNA-based therapeutics in this disease. Furthermore, these findings provide critical validation for the evolving application of network theory to the discovery of the miRNA-based origins of PH and other diseases.
CFTR regulates B cell activation and lymphoid follicle development
Background Cystic fibrosis (CF) is an inherited disorder caused by mutations in the CF transmembrane conductance regulator (CFTR) gene that promotes persistent lung infection and inflammation and progressive loss of lung function. Patients with CF have increased lung lymphoid follicles (LFs) and B cell-activating factor of tumor necrosis factor family (BAFF) that regulates B cell survival and maturation. A direct role for CFTR in B cell activation and disease pathogenesis in CF remains unclear. Methods The number of LFs, BAFF + , TLR4 + and proliferation marker Ki67 + B cells in lung explants or resections from subjects with CF and normal controls was quantified by immunostaining. The role of CFTR in B cell activation and LF development was then examined in two independent cohorts of uninfected CFTR-deficient mice ( Cftr −/− ) and wild type controls. The number of lung LFs, B cells and BAFF + , CXCR4 + , immunoglobulin G + B cells was examined by immunostaining. Lung and splenocyte B cell activation marker and major histocompatibility complex class II (MHC class II) expression was quantified by flow cytometry. Inflammatory cytokine levels were measured in supernatants from isolated B cells from Cftr −/− and wild type mice stimulated in vitro with Pseudomonas aeruginosa lipopolysaccharide (LPS). Results There was a significant increase in well-formed LFs in subjects with CF compared to normal controls. Increased B cell activation and proliferation was observed in lung LFs from CF subjects as was quantified by a significant increase in B cell BAFF, TLR4 and Ki67 expression. Uninfected Cftr −/− mice had increased lung LFs and BAFF + and CXCR4 + B cells compared to wild type controls. Lung B cells isolated from uninfected Cftr −/− mice demonstrated increased MHC class II expression. In vitro, isolated B cells from Cftr −/− mice produced increased IL-6 when stimulated with LPS compared to wild type controls. Conclusions These data support a direct role for CFTR in B cell activation, proliferation and inflammatory cytokine production that promotes lung LF follicle development in cystic fibrosis.
User evaluations offer promise for pod-intravaginal ring as a drug delivery platform: A mixed methods study of acceptability and use experiences
Effective HIV prevention requires efficient delivery of safe and efficacious drugs and optimization of user adherence. The user's experiences with the drug, delivery system, and use parameters are critical to product acceptability and adherence. Prevention product developers have the opportunity to directly control a drug delivery system and its impact on acceptability and adherence, as well as product efficacy. Involvement of potential users during preclinical design and development can facilitate this process. We embedded a mixed methods user evaluation study into a safety and pharmacokinetics (PK) trial of a pod-intravaginal ring delivering antiretroviral agents. Women enrolled in two cohorts, ultimately evaluating the safety/PK of a pod-IVRs delivering TDF-alone, TDF-FTC, and/or TDF-FTC-MVC. A 7-day use period was targeted for each pod-IVR, regardless of drug or drug combination. During the clinical study, participants provided both quantitative (i.e., survey) and qualitative (i.e., in-depth interview) data capturing acceptability, perceptibility, and adherence behaviors. Initial sexual and reproductive health history surveys, daily diaries, a final acceptability and willingness to use survey, and a qualitative in-depth interview comprised the user evaluation data for each pod-IVR experienced by the participants. Overall, the majority of participants (N = 10) reported being willing to use the pod-IVR platform for HIV prevention should it advance to market. Confidence to use the pod-IVR (e.g., insertion, removal) was high. There were no differences noted in the user experience of the pod-IVR platform; that is, whether the ring delivered TDF-alone, TDF-FTC, or TDF-FTC-MVC, users' experiences of the ring were similar and acceptable. Participants did report specific experiences, both sensory and behavioral, that impacted their use behaviors with respect to the ring, and which could ultimately impact acceptability and adherence. These experiences, and user evaluations elicited by them, could both challenge use or be used to leverage use in future trials and product rollout once fully articulated. High willingness-to-use data and lack of salient differences in user experiences related to use of the pod-IVR platform (regardless of agents delivered) suggests that the pod-IVR is a feasible and acceptable drug delivery device in and of itself. This finding holds promise both for an anti-HIV pod-IVR and, potentially, a multipurpose prevention pod-IVR that could deliver both prevention for sexually transmitted infections (STIs) including HIV and contraception. Given the very early clinical trial context, further acceptability, perceptibility, and adherence data should continue to be explored, in the context of longer use periods (e.g., 28-day ring use), and in the contexts of sexual activity and menses. Using early design and development contexts to gain insights into potential challenges and facilitators of drug delivery systems such as the pod-IVR could save valuable resources and time as a potential biomedical technology moves through the clinical trial pipeline and into real-world use.