RESUMEN
The generation of insulin-producing pancreatic ß cells from stem cells in vitro would provide an unprecedented cell source for drug discovery and cell transplantation therapy in diabetes. However, insulin-producing cells previously generated from human pluripotent stem cells (hPSC) lack many functional characteristics of bona fide ß cells. Here, we report a scalable differentiation protocol that can generate hundreds of millions of glucose-responsive ß cells from hPSC in vitro. These stem-cell-derived ß cells (SC-ß) express markers found in mature ß cells, flux Ca(2+) in response to glucose, package insulin into secretory granules, and secrete quantities of insulin comparable to adult ß cells in response to multiple sequential glucose challenges in vitro. Furthermore, these cells secrete human insulin into the serum of mice shortly after transplantation in a glucose-regulated manner, and transplantation of these cells ameliorates hyperglycemia in diabetic mice.
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Técnicas de Cultivo de Célula , Células Secretoras de Insulina/citología , Animales , Humanos , Células Madre Pluripotentes Inducidas/citología , Células Madre Pluripotentes Inducidas/metabolismo , Insulina/genética , Insulina/metabolismo , Islotes Pancreáticos , Ratones , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/metabolismoRESUMEN
Microglia, the resident immune cells of the brain, rapidly change states in response to their environment, but we lack molecular and functional signatures of different microglial populations. Here, we analyzed the RNA expression patterns of more than 76,000 individual microglia in mice during development, in old age, and after brain injury. Our analysis uncovered at least nine transcriptionally distinct microglial states, which expressed unique sets of genes and were localized in the brain using specific markers. The greatest microglial heterogeneity was found at young ages; however, several states-including chemokine-enriched inflammatory microglia-persisted throughout the lifespan or increased in the aged brain. Multiple reactive microglial subtypes were also found following demyelinating injury in mice, at least one of which was also found in human multiple sclerosis lesions. These distinct microglia signatures can be used to better understand microglia function and to identify and manipulate specific subpopulations in health and disease.
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Envejecimiento/inmunología , Lesiones Encefálicas/inmunología , Encéfalo/fisiología , Microglía/fisiología , Esclerosis Múltiple/inmunología , Adaptación Fisiológica , Envejecimiento/genética , Animales , Lesiones Encefálicas/genética , Diferenciación Celular , Enfermedades Desmielinizantes , Humanos , Longevidad , Ratones , Ratones Endogámicos C57BL , Análisis de Secuencia de ARN , Análisis de la Célula IndividualRESUMEN
A number of endogenous genes in the human genome encode retroviral gag-like proteins, which were domesticated from ancient retroelements. The paraneoplastic Ma antigen (PNMA) family members encode a gag-like capsid domain, but their ability to assemble as capsids and traffic between cells remains mostly uncharacterized. Here, we systematically investigate human PNMA proteins and find that a number of PNMAs are secreted by human cells. We determine that PNMA2 forms icosahedral capsids efficiently but does not naturally encapsidate nucleic acids. We resolve the cryoelectron microscopy (cryo-EM) structure of PNMA2 and leverage the structure to design engineered PNMA2 (ePNMA2) particles with RNA packaging abilities. Recombinantly purified ePNMA2 proteins package mRNA molecules into icosahedral capsids and can function as delivery vehicles in mammalian cell lines, demonstrating the potential for engineered endogenous capsids as a nucleic acid therapy delivery modality.
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Antígenos de Neoplasias , Cápside , Proteínas del Tejido Nervioso , Animales , Humanos , ARN Mensajero/genética , Microscopía por Crioelectrón , MamíferosRESUMEN
Tissue macrophages, including microglia, are notoriously resistant to genetic manipulation. Here, we report the creation of Adeno-associated viruses (AAV) variants that efficiently and widely transduce microglia and tissue macrophages in vivo following intravenous delivery, with transgene expression of up to 80%. We use this technology to demonstrate manipulation of microglia gene expression and microglial ablation, thereby providing invaluable research tools for the study of these important cells.
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Dependovirus , Microglía , Dependovirus/genética , Cápside , Transgenes , MacrófagosRESUMEN
An Amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Ageing causes a decline in tissue regeneration owing to a loss of function of adult stem cell and progenitor cell populations1. One example is the deterioration of the regenerative capacity of the widespread and abundant population of central nervous system (CNS) multipotent stem cells known as oligodendrocyte progenitor cells (OPCs)2. A relatively overlooked potential source of this loss of function is the stem cell 'niche'-a set of cell-extrinsic cues that include chemical and mechanical signals3,4. Here we show that the OPC microenvironment stiffens with age, and that this mechanical change is sufficient to cause age-related loss of function of OPCs. Using biological and synthetic scaffolds to mimic the stiffness of young brains, we find that isolated aged OPCs cultured on these scaffolds are molecularly and functionally rejuvenated. When we disrupt mechanical signalling, the proliferation and differentiation rates of OPCs are increased. We identify the mechanoresponsive ion channel PIEZO1 as a key mediator of OPC mechanical signalling. Inhibiting PIEZO1 overrides mechanical signals in vivo and allows OPCs to maintain activity in the ageing CNS. We also show that PIEZO1 is important in regulating cell number during CNS development. Thus we show that tissue stiffness is a crucial regulator of ageing in OPCs, and provide insights into how the function of adult stem and progenitor cells changes with age. Our findings could be important not only for the development of regenerative therapies, but also for understanding the ageing process itself.
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Células Madre Adultas/patología , Envejecimiento/patología , Sistema Nervioso Central/patología , Células Madre Multipotentes/patología , Nicho de Células Madre , Animales , Animales Recién Nacidos , Recuento de Células , Matriz Extracelular/patología , Femenino , Humanos , Proteínas de la Membrana/antagonistas & inhibidores , Proteínas de la Membrana/metabolismo , Oligodendroglía/patología , Ratas , Nicho de Células Madre/fisiologíaRESUMEN
BACKGROUND: Ventricular septal motion abnormalities (VSMA) are common echocardiographic finding in patients with pulmonary hypertension (PHTN). This study sought to evaluate the relationship between echocardiographic findings and the classification of PHTN. METHODS: This study retrospectively studied 146 consecutive patients referred for right heart catheterisation for clinically suspected PHTN. VSMA were defined as any echocardiographic description of leftward abnormal septal motion or position. RESULTS: VSMA were present in 42 patients (29%). Patients with VSMA were younger and more likely to have prior pulmonary embolism. They also had less obstructive sleep apnoea, hypertension and dyslipidaemia. By echocardiography, patients with VSMA had lower left ventricular mass, left atrial size and lateral wall E/e' ratio. At cardiac catheterisation, PHTN was confirmed in all (100%) patients with VSMA (compared with 75% in patients without VSMA); 98% with VSMA had elevated pulmonary vascular resistance (compared with 55% without VSMA; p<0.005 for all). VSMA were found to have 91% sensitivity and 51% specificity for the diagnosis of pre-capillary PHTN. On multivariate analysis, VSMA were found to be strong independent predictors for the diagnosis of pre-capillary PHTN (HR, 9.15; 95% CI, 3.0-28.2; p<0.001). Left atrial enlargement was also a strong negative predictor for pre-capillary PHTN (HR, 0.14; 95% CI, 0.05-0.36; p<0.001). CONCLUSION: Ventricular septal motion abnormalities were strongly associated with pre-capillary PHTN in patients with suspected PHTN. The findings suggest that patients with VSMA should be further evaluated by right heart catheterisation.
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Hipertensión Pulmonar , Ecocardiografía , Humanos , Hipertensión Pulmonar/diagnóstico por imagen , Estudios Retrospectivos , Resistencia Vascular , Función Ventricular IzquierdaRESUMEN
BACKGROUND: Methacholine challenge tests (MCTs) are used to diagnose airway hyperresponsiveness (AHR) in patients with suspected asthma where previous diagnostic testing has been inconclusive. The test is time consuming and usually requires referral to specialized centers. Simple methods to predict AHR could help determine which patients should be referred to MCTs, thus avoiding unnecessary testing. Here we investigated the potential use of baseline spirometry variables as surrogate markers for AHR in adults with suspected asthma. METHODS: Baseline spirometry and MCTs performed between 2013 and 2019 in a large tertiary center were retrospectively evaluated. Receiver-operating characteristic curves for the maximal expiratory flow-volume curve indices (angle ß, FEV1, FVC, FEV1/FVC, FEF50%, FEF25-75%) were constructed to assess their overall accuracy in predicting AHR and optimal cutoff values were identified. RESULTS: A total of 2983 tests were analyzed in adults aged 18-40 years. In total, 14% of all MCTs were positive (PC20 ≤ 16 mg/ml). All baseline spirometry parameters were significantly lower in the positive group (p < 0.001). FEF50% showed the best overall accuracy (AUC = 0.688) and proved to be useful as a negative predictor when applying FEF50% ≥ 110% as a cutoff level. CONCLUSIONS: This study highlights the role of FEF50% in predicting AHR in patients with suspected asthma. A value of ≥ 110% for baseline FEF50% could be used to exclude AHR and would lead to a substantial decrease in MCT referrals.
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Asma/diagnóstico , Hiperreactividad Bronquial/diagnóstico , Pruebas de Provocación Bronquial , Broncoconstrictores/administración & dosificación , Cloruro de Metacolina/administración & dosificación , Espirometría , Adulto , Asma/fisiopatología , Hiperreactividad Bronquial/fisiopatología , Estudios Transversales , Femenino , Volumen Espiratorio Forzado , Humanos , Israel , Modelos Logísticos , Masculino , Valor Predictivo de las Pruebas , Curva ROC , Estudios Retrospectivos , Capacidad Vital , Adulto JovenRESUMEN
BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, distinct pulmonary vascular disease caused by chronic obstruction of major pulmonary arteries, which can be cured by pulmonary endarterectomy. However, many CTEPH patients are not surgical candidates. Balloon pulmonary angioplasty (BPA) is an emerging technique used to treat inoperable CTEPH. OBJECTIVES: To describe the first Israeli experience with BPA for inoperable CTEPH. METHODS: In 2017 we established a BPA program at our institution. We reviewed the outcomes to date of BPA in our center. RESULTS: Forty-seven BPA procedures were performed in five patients with inoperable CTEPH (4-17 procedures/patient). Mean pulmonary artery pressure improved in all patients (median decrease 17 mmHg, range 10-26 mmHg). Pulmonary vascular resistance also improved (median decrease 11 Woods Units/m2, range 8-16 Woods Units/m2). Cardiac output increased in 4 of 5 patients and decreased in one. Functional capacity improved from New York Heart Association (NYHA) III to II in four patients; one patient was NYHA II at baseline without change after BPA. Six-minute walking distance improved by a median of 97 meters. (range 21-197 meters). Hemodynamic and functional improvements were sustained at follow-up 5-11 months after the last BPA procedure. BPA enabled 2 of 3 patients treated with parenteral prostanoids to be switched to oral therapy. There were no major complications. CONCLUSIONS: We successfully established BPA as a treatment for inoperable CTEPH in our center. BPA resulted in hemodynamic and clinical improvements that were sustained over time.
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Angioplastia de Balón , Hipertensión Pulmonar/terapia , Embolia Pulmonar/terapia , Adulto , Angioplastia de Balón/métodos , Femenino , Hemodinámica , Humanos , Hipertensión Pulmonar/etiología , Masculino , Persona de Mediana Edad , Arteria Pulmonar , Embolia Pulmonar/complicaciones , Estudios RetrospectivosRESUMEN
It is now well-established that the macrophage and microglial response to CNS demyelination influences remyelination by removing myelin debris and secreting a variety of signaling molecules that influence the behaviour of oligodendrocyte progenitor cells (OPCs). Previous studies have shown that changes in microglia contribute to the age-related decline in the efficiency of remyelination. In this study, we show that microglia increase their expression of the proteoglycan NG2 with age, and that this is associated with an altered micro-niche generated by aged, but not young, microglia that can divert the differentiation OPCs from oligodendrocytes into astrocytes in vitro. We further show that these changes in ageing microglia are generated by exposure to high levels of TGFß. Thus, our findings suggest that the rising levels of circulating TGFß known to occur with ageing contribute to the age-related decline in remyelination by impairing the ability of microglia to promote oligodendrocyte differentiation from OPCs, and therefore could be a potential therapeutic target to promote remyelination.
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Senescencia Celular/fisiología , Microglía/metabolismo , Células Precursoras de Oligodendrocitos/metabolismo , Oligodendroglía/metabolismo , Factor de Crecimiento Transformador beta/farmacología , Factores de Edad , Animales , Animales Recién Nacidos , Diferenciación Celular/fisiología , Células Cultivadas , Senescencia Celular/efectos de los fármacos , Sistema Nervioso Central/efectos de los fármacos , Sistema Nervioso Central/metabolismo , Relación Dosis-Respuesta a Droga , Microglía/efectos de los fármacos , Células Precursoras de Oligodendrocitos/efectos de los fármacos , Oligodendroglía/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
Remyelination is a neuroprotective regenerative response to demyelination that restores saltatory conduction and decreases the vulnerability of axons to irreversible degeneration. It is a highly efficient process: however, as with all regenerative processes, its efficiency declines with ageing. Here we argue that this age-related decline in remyelination has a major impact on the natural history of multiple sclerosis (MS), a disease often of several decades' duration. We describe recent work on (1) how ageing changes the function of oligodendrocyte progenitor cells (OPCs), the cells primarily responsible for generating new myelin-forming oligodendrocytes in remyelination, (2) how these changes are induced by age-related changes in the OPC niche and (3) how these changes can be reversed, thereby opening up the possibility of therapeutically maintaining remyelination efficiency throughout the disease, preserving axonal health and treating the progressive phase of MS.
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Envejecimiento/fisiología , Células Precursoras de Oligodendrocitos/fisiología , Remielinización/fisiología , Sustancia Blanca/fisiología , HumanosRESUMEN
BACKGROUND: Lung injury with development of the acute respiratory distress syndrome (ARDS) is a serious complication which can occur after major surgery, including cardiac surgery. OBJECTIVE: The aim of our study was to compare the prevalence, risk factors, and mortality of ARDS following cardiac surgery according to the American-European Consensus Conference (AECC) definition and the new Berlin definition of ARDS. METHODS: We performed a retrospective, observational study that included prospectively collected data from consecutive adult patients, aged from 18 to 92 years, who had undergone cardiac surgery (both on and off pump) at a large tertiary university hospital over 5 years (from September 2012 to September 2017). RESULTS: During the study period, 3,972 patients underwent cardiac surgery, and 3,946 patients were included in the study. Fifty-five patients developed ARDS (1.14%) according to the AECC definition and 59 patients (1.15%) according to the Berlin definition, with a mortality of 32.7 and 30.5%, respectively (18 patients). Multivariate regression analysis identified prior cardiac surgery, complex cardiac surgery, emergency procedures, and transfusion of > 3 packed red blood cell units as predictors for ARDS. CONCLUSION: The development of ARDS in patients after cardiac surgery is a rare but serious complication associated with significant mortality. Moreover, our findings showed that prevalence, mortality, and risk factors for developing ARDS were similar according to both the AECC and the new Berlin definition.
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Procedimientos Quirúrgicos Cardíacos/efectos adversos , Complicaciones Posoperatorias/diagnóstico , Complicaciones Posoperatorias/epidemiología , Síndrome de Dificultad Respiratoria/diagnóstico , Síndrome de Dificultad Respiratoria/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Consenso , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia , Adulto JovenRESUMEN
BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is a rare, distinct pulmonary vascular disease, which is caused by chronic obstruction of major pulmonary arteries. CTEPH can be cured by pulmonary endarterectomy (PEA). PEA for CTEPH is a challenging procedure, and patient selection and the perioperative management are complex, requiring significant experience. OBJECTIVES: To describe the establishment of a national CTEPH-PEA center in Israel and present results of surgery. METHODS: In this study, we reviewed the outcomes of PEA in a national referral, multi-disciplinary center for CTEPH-PEA. The center was established by collaborating with a high-volume center in Europe. A multidisciplinary team from our hospital (pulmonary hypertension specialist, cardiac surgeon, cardiac anesthesiologist and cardiac surgery intensivist was trained under the guidance of an experienced team from the European center. RESULTS: A total of 38 PEA procedures were performed between 2008 and 2018. We included 28 cases in this analysis for which long-term follow-up data were available. There were two hospital deaths (7%). At follow-up, median New York Heart Association (NYHA) class improved from III to I (P < 0.0001), median systolic pulmonary pressure decreased from 64 mmHg to 26 mmHg (P < 0.0001), and significant improvements were seen in right ventricular function and exercise capacity. CONCLUSIONS: A national center for performance of a rare and complex surgical procedure can be successfully established by collaboration with a high-volume center and by training a dedicated multidisciplinary team.
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Endarterectomía/métodos , Hipertensión Pulmonar/etiología , Hipertensión Pulmonar/cirugía , Embolia Pulmonar/complicaciones , Embolia Pulmonar/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Enfermedad Crónica , Femenino , Humanos , Israel , Masculino , Persona de Mediana Edad , Arteria Pulmonar/cirugía , Derivación y Consulta , Factores de Riesgo , Resultado del Tratamiento , Adulto JovenAsunto(s)
Betacoronavirus/aislamiento & purificación , Repeticiones Palindrómicas Cortas Agrupadas y Regularmente Espaciadas , Infecciones por Coronavirus/diagnóstico , Neumonía Viral/diagnóstico , ARN Viral/análisis , Betacoronavirus/genética , COVID-19 , Sistemas CRISPR-Cas , Técnicas de Laboratorio Clínico/métodos , Humanos , Pandemias , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , SARS-CoV-2 , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: Symptom control is a primary goal in asthma. We hypothesized that administrative data regarding rescue inhaler purchases may correlate with asthma symptom control. METHODS: We identified all patients who purchased short-acting beta-agonist (SABA) inhalers during the course of one year in the database of a Health Maintenance Organization (HMO). Primary physicians identified asthma patients and classified their asthma symptom control into three groups according to the Global Initiative for Asthma (GINA) guidelines. Asthma patients were asked to answer symptom questionnaires and grade their asthma control. SABA inhaler purchases were compared between asthma control groups as classified by the guidelines, the physicians and the patients. We also compared the agreement on asthma control between the three methods of classification. RESULTS: Of 241 asthma patients, 83 completed the questionnaires. Using the GINA guidelines criteria, 26 were symptom controlled, 46 were partially controlled and 11 were uncontrolled. SABA inhaler purchases were not significantly lower in the controlled group. Using patients' overall impression of their asthma control, the mean numbers of SABA inhalers purchased were 1.5, 4.4 and 6.4 per year in the controlled, partially controlled and uncontrolled groups, respectively (p = 0.03). Patients' classification of asthma control had better agreement (kappa = 0.34) with GINA guidelines than physician's' agreement (kappa = 0.05). CONCLUSION: When using administrative data for asthma patients, 2 or more SABA inhaler purchases in one year should alert the physician for the need for asthma control evaluation. Purchase of at least 4 SABA inhalers a year may be regarded as a marker for asthma that is not controlled.
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Agonistas de Receptores Adrenérgicos beta 2/uso terapéutico , Asma/tratamiento farmacológico , Administración por Inhalación , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Nebulizadores y Vaporizadores , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
OBJECTIVES: To assess the added diagnostic value of using exercise hemodynamics during RHC in assessment of patients with symptomatic SSc. METHODS: We performed 22 RHCs in 17 SSc patients with dyspnea and/or pulmonary arterial hypertension (PAH). Exercise was performed in 15 RHCs using isotonic arm exercises while holding a 1 kg weight in each hand. Measurements of pulmonary arterial pressure (PAP), pulmonary arterial wedge pressure (PAWP), and cardiac output (CO) were taken at rest and during peak exercise. RESULTS: Normal resting RHC (PAP 22 ï± 3 mmHg, PAWP 11 ï± 3 mmHg) was found in seven cases. Of these, exercise induced elevation in PAP was found in three (38 ï± 7 mmHg), and exercise induced elevation in PAWP was found in four (24 ï± 6 mmHg). Elevated resting PAP was found in 15 (41 ï± 11 mmHg) with minor changes in exercise. Of the 22 RHCs, elevation of the PAWP was found in 11 (50%), half of which were in response to exercise. CONCLUSIONS: In symptomatic SSc patients, exercise hemodynamics provides important information on diastolic dysfunction that is not available with non-invasive testing. Findings on exercise RHC can explain patient symptoms in up to 50% of cases. Earlier and more accurate diagnosis of patient symptoms can aid in tailoring the correct therapy for each.
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Disnea/etiología , Prueba de Esfuerzo/métodos , Cardiopatías/diagnóstico , Hipertensión Pulmonar/diagnóstico , Esclerodermia Sistémica/fisiopatología , Adulto , Presión Arterial , Cateterismo Cardíaco/métodos , Gasto Cardíaco/fisiología , Disnea/diagnóstico , Femenino , Cardiopatías/etiología , Hemodinámica/fisiología , Humanos , Hipertensión Pulmonar/fisiopatología , Masculino , Persona de Mediana Edad , Arteria Pulmonar , Presión Esfenoidal Pulmonar , Estudios Retrospectivos , Adulto JovenRESUMEN
Transthoracic Parametric Doppler (TPD) is a novel ultrasound technique recently developed for the investigation of pulmonary blood vessels. Lung Doppler Signals (LDS) recorded from TPD provide information regarding the functional mechanical characteristics of pulmonary blood vessels. We aimed to define the specific profile of LDS generated from TPD imaging in patients with pulmonary hypertension (PH), and to evaluate the diagnostic performance of LDS to detect PH using right heart catheterization (RHC) as gold standard reference. Seventy nine PH patients and 79 healthy controls matched for age, gender and BMI were recruited in a prospective case-control multicenter study. LDS recordings were performed by TPD consisting of a pulsed Doppler with a 2 MHz single element transducer. LDS were recorded within 24 h of RHC. Following LDS extraction, classification and performance evaluation were performed offline using a support vector machine (k-fold cross validation method). The best LDS parameters for PH detection were (1) peak velocity of the systolic (S) and diastolic (D) signals, (2) the rise slope of the S and D signals, and (3) time to peak of the S signal. Overall, the sensitivity and specificity of TPD for detection of PH were 82.7 % (95 % CI 81.3-84.1) and 87.4 % (95 % CI 86.3-88.5), respectively, with an area under the receiver operating curve of 0.95 (95 % CI 0.94-0.96). Detection rate of PH increased progressively with the level of mean pulmonary artery pressure. LDS recorded by TPD display a specific profile in PH and appears to be a promising and reliable tool for PH diagnosis. Further studies are required to confirm the clinical usefulness of LDS.
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Diagnóstico por Computador/métodos , Ecocardiografía Doppler/métodos , Hipertensión Pulmonar/diagnóstico por imagen , Pulmón/fisiopatología , Presión Esfenoidal Pulmonar , Adulto , Anciano , Área Bajo la Curva , Vasos Sanguíneos , Cateterismo Cardíaco , Estudios de Casos y Controles , Análisis por Conglomerados , Reacciones Falso Positivas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prueba de Estudio Conceptual , Estudios Prospectivos , Arteria Pulmonar/fisiopatología , Curva ROC , Proyectos de Investigación , Sensibilidad y Especificidad , Procesamiento de Señales Asistido por ComputadorRESUMEN
PURPOSE: We studied the effect of O2 supplementation on physiological response to exercise in patients with moderate to severe interstitial lung disease (ILD). METHODS: 13 patients (age 66 ± 10 yrs., 7 males) with ILD (TLC 71 ± 22% predicted, carbon monoxide diffusion capacity (DLCO) 44 ± 16% predicted) and 13 healthy individuals (age 50 ± 17 yrs., 7 males) were tested. ILD patients performed symptom-limited cardiopulmonary exercise tests and constant work-rate tests (CWRTs) at 80% of the work-rate (WR) at the gas exchange threshold (GET). Tests breathing room air (RA, 21% O2) were compared to tests performed breathing 30% O2. Oxygen-uptake (VÌO2) kinetics were calculated from the CWRT results. RESULTS: In the ILD group, peak WR, peak VÌO2 and VÌO2 at the GET improved significantly when breathing 30% O2 compared to RA (mean ± SD 66 ± 23 vs 75 ± 26 watts, 15 ± 2 vs 17 ± 4 ml/kg/min and 854 ± 232 vs 932 ± 245 ml/min; p = 0.004, p = 0.001 and p = 0.01, respectively). O2 saturation (SPO2%) at peak exercise was higher with 30% O2 (97 ± 4% vs 88 ± 9%, p = 0.002). The time constant (tau) of VÌO2 kinetics was faster in ILD patients while breathing 30% O2 (41 ± 10 sec) compared to RA (52 ± 14 sec, p = 0.003). There was a negative linear relation between tau and SPO2% with RA (r = -0.76, p = 0.006) and while breathing 30% O2 (r = -0.68, p = 0.02). CONCLUSIONS: Using a clinically applicable level of O2 supplementation (30%) improved maximal, aerobic exercise capacity and VÌO2 kinetics in ILD patients, likely due to increased blood O2 content subsequently increasing the O2 delivery to the working muscles.
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BACKGROUND: Plasma asymmetric dimethylarginine (ADMA) is elevated in pulmonary arterial hypertension (PAH) and is associated with unfavorable outcomes. OBJECTIVES: The aim of this study was to assess changes in ADMA plasma levels for monitoring disease progression and outcomes during PAH-specific therapy. METHODS: ADMA was measured at baseline and after at least 6 months of follow-up using enzyme-linked immunosorbent assay and high-performance liquid chromatography. Changes in ADMA were analyzed in relation to changes in established PAH markers, including hemodynamic status, N-terminal pro-brain natriuretic peptide (NT-proBNP) and risk assessment scores. Impact on survival was assessed using Kaplan-Meier curves and Cox proportional hazards models. RESULTS: Between 2008 and 2019, ADMA samples were collected prospectively from 215 patients with PAH. Change in ADMA plasma level was a predictor of disease progression and survival. ΔADMA (median -0.03 µmol/L; 95% CI: -0.145 to 0.0135) was correlated with change in mean pulmonary arterial pressure (P < 0.005; rS = 0.287) but was not significantly correlated with ΔNT-proBNP (P = 0.056; rS = 0.135). Patients with decreased ADMA plasma levels at follow-up had better 3-year and 5-year survival rates (88% and 80%, respectively, vs 72% and 53% in those without decreases in ADMA) (P < 0.005; pulmonary hypertension-related mortality or lung transplantation). Patients with decreases in both ADMA and NT-proBNP had better survival rates compared with patients in whom only 1 parameter improved (P < 0.005). ΔADMA was a significant predictor of survival in Cox regression analysis and also when corrected for ΔNT-proBNP (HRs: 1.27 and 1.35, respectively; P < 0.005). CONCLUSIONS: ADMA and NT-proBNP provide synergistic prognostic information for patients with PAH. ADMA could be used as an objective and distinct biomarker for monitoring treatment response in PAH.
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Arginina , Biomarcadores , Progresión de la Enfermedad , Péptido Natriurético Encefálico , Fragmentos de Péptidos , Hipertensión Arterial Pulmonar , Humanos , Péptido Natriurético Encefálico/sangre , Arginina/análogos & derivados , Arginina/sangre , Femenino , Masculino , Fragmentos de Péptidos/sangre , Persona de Mediana Edad , Biomarcadores/sangre , Hipertensión Arterial Pulmonar/sangre , Hipertensión Arterial Pulmonar/fisiopatología , Estudios Prospectivos , Adulto , Pronóstico , Anciano , Hipertensión Pulmonar/sangre , Hipertensión Pulmonar/fisiopatologíaRESUMEN
BACKGROUND: The methacholine challenge test (MCT) is a test of bronchial hyperreactivity used as an aid in the diagnosis of asthma. MCT results are reported as the provocation concentration at which the forced expiratory volume in 1 second (FEV1) decreases 20% (PC20). The requirement for a 20% or greater decrease in FEV1 results in precipitous decreases in FEV1 in some patients. OBJECTIVE: To improve MCT safety without compromising accuracy. METHODS: We performed a retrospective analysis of 879 consecutive MCTs (derivation cohort). A novel protocol for MCT was developed and validated in a cohort of 564 MCTs performed in a second institution. RESULTS: In comparison with a PC20 cutoff of less than 8 mg/mL, a provocation concentration at which the FEV1 decreases 10% (PC10) cutoff of 1 mg/mL or less has a sensitivity of 86%, a specificity of 98%, a positive predictive value (PPV) of 97%, and a negative predictive value (NPV) of 91%. We propose a novel 2-tiered protocol for MCT. If the PC10 is 1 mg/mL or less, bronchial hyperreactivity is present; if the PC10 is greater than 1 mg/mL, the test is continued until the provocative concentration is 8 mg/mL or a 20% decrease in FEV1 is achieved. Compared with the standard protocol, the proposed protocol has a sensitivity, specificity, PPV, NPV, and overall accuracy of 100%, 98%, 97.6%, 100%, and 99%, respectively. The modified protocol would have enabled us to avoid 26 of 42 cases (62%) in which a 40% or greater decrease in FEV1 occurred and would save 0.65 dose for every MCT performed. The 2-tiered protocol performed well in the validation cohort; sensitivity, specificity, PPV, NPV, and overall accuracy were 100%, 98%, 87%, 100%, and 98%, respectively. CONCLUSION: The proposed 2-tiered protocol is accurate, saves time, and avoids precipitous decreases in FEV1.