RESUMO
OBJECTIVES: To validate a mathematical model using porous media theory for alveolar CO2 determination in ventilated patients. DESIGN: Mathematical modeling study with prospective clinical validation to simulate CO2 exchange from bloodstream to airway entrance. SETTING: ICU. PATIENTS: Thirteen critically ill patients without chronic or acute lung disease. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Model outcomes compared with patient data showed correlations for end-tidal CO2 (EtCO 2 ), area under the CO2 curve, and Pa CO2 of 0.918, 0.954, and 0.995. Determination coefficients ( R2 ) were 0.843, 0.910, and 0.990, indicating precision and predictive power. CONCLUSIONS: The mathematical model shows potential in pulmonary critical care. Although promising, practical application demands further validation, clinician training, and patient-specific adjustments. The path to clinical use will be iterative, involving validation and education.
Assuntos
Dióxido de Carbono , Alvéolos Pulmonares , Respiração Artificial , Humanos , Dióxido de Carbono/análise , Masculino , Pessoa de Meia-Idade , Feminino , Estudos Prospectivos , Idoso , Alvéolos Pulmonares/metabolismo , Unidades de Terapia Intensiva , Adulto , Modelos Teóricos , Troca Gasosa Pulmonar/fisiologia , Estado Terminal/terapia , PorosidadeRESUMO
Idiopathic pulmonary fibrosis (IPF) is a lethal age-related lung disease whose pathogenesis involves an aberrant response of alveolar epithelial cells (AEC). Activated epithelial cells secrete mediators that participate in the activation of fibroblasts and the excessive deposition of extracellular matrix proteins. Previous studies indicate that matrix metalloproteinase 14 (MMP14) is increased in the lung epithelium in patients with IPF, however, the role of this membrane-type matrix metalloproteinase has not been elucidated. In this study, the role of Mmp14 was explored in experimental lung fibrosis induced with bleomycin in a conditional mouse model of lung epithelial MMP14-specific genetic deletion. Our results show that epithelial Mmp14 deficiency in mice increases the severity and extension of fibrotic injury and affects the resolution of the lesions. Gain-and loss-of-function experiments with human epithelial cell line A549 demonstrated that cells with a deficiency of MMP14 exhibited increased senescence-associated markers. Moreover, conditioned medium from these cells increased fibroblast expression of fibrotic molecules. These findings suggest a new anti-fibrotic mechanism of MMP14 associated with anti-senescent activity, and consequently, its absence results in impaired lung repair. Increased MMP14 in IPF may represent an anti-fibrotic mechanism that is overwhelmed by the strong profibrotic microenvironment that characterizes this disease.
Assuntos
Células Epiteliais/patologia , Fibrose Pulmonar Idiopática/genética , Metaloproteinase 14 da Matriz/genética , Alvéolos Pulmonares/metabolismo , Células A549 , Actinas/genética , Actinas/metabolismo , Animais , Bleomicina/administração & dosagem , Senescência Celular/genética , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Modelos Animais de Doenças , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Fibronectinas/genética , Fibronectinas/metabolismo , Regulação da Expressão Gênica , Humanos , Hipoxantina Fosforribosiltransferase/genética , Hipoxantina Fosforribosiltransferase/metabolismo , Fibrose Pulmonar Idiopática/induzido quimicamente , Fibrose Pulmonar Idiopática/metabolismo , Fibrose Pulmonar Idiopática/patologia , Metaloproteinase 14 da Matriz/deficiência , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Cultura Primária de Células , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/patologia , Succinato Desidrogenase/genética , Succinato Desidrogenase/metabolismo , Fator de Crescimento Transformador beta1/genética , Fator de Crescimento Transformador beta1/metabolismoRESUMO
We present results from clinical, radiologic, gas exchange, lung mechanics, and fibre-optic bronchoscopy-guided transbronchial biopsies in a case of acute respiratory failure due to SARS-CoV-2 (Covid-19). This report highlights the pulmonary, immunological, and inflammatory changes found during acute diffuse alveolar damage and the later organizing phase. An early diffuse alveolar damage pattern with predominant epithelial involvement with active recruitment of T cells and monocytes was observed followed by a late organizing pattern with pneumocyte hyperplasia, inflammatory infiltration, prominent endotheliitis, and secondary germinal centers. The patient's deterioration paralleling the late immuno-pathological findings based the decision to administer intravenous corticosteroids, resulting in clinical, gasometric, and radiologic improvement. We believe that real-time clinicopathological correlation, along with the description of the immunological processes at play, will contribute to the full clinical picture of Covid-19 and might lead to a more rational approach in the precise timing of anti-inflammatory, anti-cytokine, or steroid therapies.
Assuntos
Brônquios/patologia , Tratamento Farmacológico da COVID-19 , Esteroides/uso terapêutico , Idoso , Células Epiteliais Alveolares/metabolismo , Células Epiteliais Alveolares/virologia , Biópsia/métodos , Brônquios/virologia , COVID-19/patologia , COVID-19/virologia , Humanos , Pulmão/patologia , Masculino , Alvéolos Pulmonares/metabolismo , Alvéolos Pulmonares/virologia , Insuficiência Respiratória/tratamento farmacológico , Insuficiência Respiratória/patologia , Insuficiência Respiratória/virologia , SARS-CoV-2/isolamento & purificaçãoRESUMO
SARS-CoV-2, the pathogenic agent of COVID-19, employs angiotensin converting enzyme-2 (ACE2) as its cell entry receptor. Clinical data reveal that in severe COVID-19, SARS-CoV-2 infects the lung, leading to a frequently lethal triad of respiratory insufficiency, acute cardiovascular failure, and coagulopathy. Physiologically, ACE2 plays a role in the regulation of three systems that could potentially be involved in the pathogenesis of severe COVID-19: the kinin-kallikrein system, resulting in acute lung inflammatory edema; the renin-angiotensin system, promoting cardiovascular instability; and the coagulation system, leading to thromboembolism. Here we assembled a healthy human lung cell atlas meta-analysis with ~ 130,000 public single-cell transcriptomes and show that key elements of the bradykinin, angiotensin and coagulation systems are co-expressed with ACE2 in alveolar cells and associated with their differentiation dynamics, which could explain how changes in ACE2 promoted by SARS-CoV-2 cell entry result in the development of the three most severe clinical components of COVID-19.
Assuntos
Betacoronavirus/genética , Coagulação Sanguínea , Perfilação da Expressão Gênica , Sistema Calicreína-Cinina/genética , Peptidil Dipeptidase A/genética , Alvéolos Pulmonares/citologia , Sistema Renina-Angiotensina/genética , Enzima de Conversão de Angiotensina 2 , Betacoronavirus/enzimologia , Betacoronavirus/fisiologia , Humanos , Alvéolos Pulmonares/metabolismo , SARS-CoV-2 , Serina Endopeptidases/genéticaRESUMO
Angiotensin-(1-7) [Ang-(1-7)], a peptide of the renin-angiotensin system, has anti-inflammatory, anti-fibrotic and antiproliferative effects in acute or chronic inflammatory disease of respiratory system. In this study, we evaluated the effect of treatment with Ang-(1-7) on pulmonary tissue damage and behavior of mice submitted to experimental model of elastase-induced pulmonary emphysema (PE). Initially, male C57BL/6 mice were randomly assigned into two main groups: control (CTRL) and PE. In the PE group, the animals received three intratracheal instillations of pancreatic porcine elastase (PPE) at 1-week intervals (0.2 IU in 50 µL of saline). The CTRL group received the same volume of saline solution (50 µL). Twenty-four hours after the last instillation, animals of the PE group were randomly divided into two groups: PE and PE + Ang-(1-7). The PE + Ang-(1-7) group was treated with 60 µg/kg of Ang-(1-7) and 92 µg kg of HPßCD in gavage distilled water, 100 µl. The CTRL and PE groups were treated with vehicle (HPßCD- 92 µg/kg in distilled water per gavage, 100 µl), orally daily for 3 weeks. On the 19th day of treatment, all groups were tested in relation to locomotor activity and exploratory behavior. After 48 h, the animals were euthanized and lungs were collected. The animals of PE group presented rupture of alveolar walls and consequently reduction of alveolar tissue area. Treatment with Ang-(1-7) partially restored the alveolar tissue area. The PE reduced the locomotor activity and the exploratory behavior of the mice in relation to the control group. Treatment with Ang-(1-7) attenuated this change. In addition, it was observed that Ang-(1-7) reduced lung levels of IL-1ß and increased levels of IL-10. These results show an anti-inflammatory effect of Ang-(1-7), inducing the return of pulmonary homeostasis and attenuation of the behavioral changes in experimental model of PE by elastase.
Assuntos
Angiotensina I/farmacologia , Pulmão/efeitos dos fármacos , Elastase Pancreática/farmacologia , Fragmentos de Peptídeos/farmacologia , Enfisema Pulmonar/tratamento farmacológico , Administração Oral , Animais , Modelos Animais de Doenças , Homeostase/efeitos dos fármacos , Interleucina-1beta/metabolismo , Locomoção/efeitos dos fármacos , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Alvéolos Pulmonares/efeitos dos fármacos , Alvéolos Pulmonares/metabolismo , Enfisema Pulmonar/metabolismo , SuínosRESUMO
Acute respiratory distress syndrome (ARDS) is a multifactorial, inflammatory lung injury disease with high morbidity and mortality. However, the underlying pathogenic mechanism remains unknown. In this study, lipopolysaccharide (LPS)-stimulated alveolar epithelial cells were used to mimic the inflammatory pathogenesis of ARDS in vitro. We here investigated the role of miR-424 in LPS-stimulated alveolar epithelial cells and found it to be substantially downregulated. Overexpression of miR-424 inhibited apoptosis and inflammation in LPS-stimulated alveolar epithelial cells, and the miR-424 inhibitor exhibited the opposite effect. A bioinformatic analysis revealed a potential binding site of miR-424 in the 3'-UTR of fibroblast growth factor 2 (FGF2). A luciferase reporter assay suggested that miR-424 targeted FGF2 in alveolar epithelial cells. The level of FGF2 protein was inhibited by miR-424 mimic, whereas was significantly upregulated after miR-424 suppression in LPS-stimulated alveolar epithelial cells. MiR-424 also exhibited the protective role in LPS-induced apoptosis and inflammation by directly targeting FGF2 via the NF-κB pathway. In conclusion, our results demonstrate that miR-424 had a protective role in LPS-induced apoptosis and inflammation of alveolar epithelial cells by targeting FGF2 via regulating NF-κB pathway. This might contribute novel evidence to help identify a therapeutic target for treating ARDS.
Assuntos
Células A549/metabolismo , Apoptose/efeitos dos fármacos , Fator 2 de Crescimento de Fibroblastos/fisiologia , Inflamação/fisiopatologia , Lipopolissacarídeos/farmacologia , MicroRNAs/metabolismo , NF-kappa B/metabolismo , Alvéolos Pulmonares/metabolismo , Mucosa Respiratória/metabolismo , Transdução de Sinais , Células A549/fisiologia , Apoptose/fisiologia , Western Blotting , Fator 2 de Crescimento de Fibroblastos/metabolismo , Imunofluorescência , Humanos , Inflamação/metabolismo , MicroRNAs/fisiologia , Alvéolos Pulmonares/citologia , Alvéolos Pulmonares/fisiologia , Reação em Cadeia da Polimerase em Tempo Real , Mucosa Respiratória/citologia , Mucosa Respiratória/fisiologia , Transdução de Sinais/fisiologiaRESUMO
NEW FINDINGS: What is the central question of this study? Clinical reports have described and suggested central and peripheral respiratory abnormalities in Parkinson's disease (PD) patients; however, these reports have never addressed the occurrence of these abnormalities in an animal model. What is the main finding and its importance? A mouse model of PD has reduced neurokinin-1 receptor immunoreactivity in the pre-BÓ§tzinger complex and Phox2b-expressing neurons in the retrotrapezoid nucleus. The PD mouse has impairments of respiratory frequency and the hypercapnic ventilatory response. Lung collagen deposition and ribcage stiffness appear in PD mice. ABSTRACT: Parkinson's disease (PD) is a neurodegenerative motor disorder characterized by dopaminergic deficits in the brain. Parkinson's disease patients may experience shortness of breath, dyspnoea, breathing difficulties and pneumonia, which can be linked as a cause of morbidity and mortality of those patients. The aim of the present study was to clarify whether a mouse model of PD could develop central brainstem and lung respiratory abnormalities. Adult male C57BL/6 mice received bilateral injections of 6-hydroxydopamine (10 µg µl-1 ; 0.5 µl) or vehicle into the striatum. Ventilatory parameters were assessed in the 40 days after induction of PD, by whole-body plethysmography. In addition, measurements of respiratory input impedance (closed and opened thorax) were performed. 6-Hydroxydopamine reduced the number of tyrosine hydroxylase neurons in the substantia nigra pars compacta, the density of neurokinin-1 receptor immunoreactivity in the pre-BÓ§tzinger complex and the number of Phox2b neurons in the retrotrapezoid nucleus. Physiological experiments revealed a reduction in resting respiratory frequency in PD animals, owing to an increase in expiratory time and a blunted hypercapnic ventilatory response. Measurements of respiratory input impedance showed that only PD animals with the thorax preserved had increased viscance, indicating that the ribcage could be stiff in this animal model of PD. Consistent with stiffened ribcage mechanics, abnormal collagen deposits in alveolar septa and airways were observed in PD animals. Our data showed that our mouse model of PD presented with neurodegeneration in respiratory brainstem centres and disruption of lung mechanical properties, suggesting that both central and peripheral deficiencies contribute to PD-related respiratory pathologies.
Assuntos
Doença de Parkinson Secundária/fisiopatologia , Transtornos Respiratórios/etiologia , Transtornos Respiratórios/fisiopatologia , Animais , Fenômenos Biomecânicos , Colágeno/metabolismo , Hipercapnia/fisiopatologia , Pulmão/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microinjeções , Neostriado , Oxidopamina , Doença de Parkinson Secundária/induzido quimicamente , Pletismografia , Alvéolos Pulmonares/metabolismo , Taxa Respiratória , Costelas/fisiopatologiaRESUMO
The respiratory system mechanics depend on the characteristics of the lung and chest wall and their interaction. In patients with acute respiratory distress syndrome under mechanical ventilation, the monitoring of airway plateau pressure is fundamental given its prognostic value and its capacity to assess pulmonary stress. However, its validity can be affected by changes in mechanical characteristics of the chest wall, and it provides no data to correctly titrate positive end-expiratory pressure by restoring lung volume. The chest wall effect on respiratory mechanics in acute respiratory distress syndrome has not been completely described, and it has likely been overestimated, which may lead to erroneous decision making. The load imposed by the chest wall is negligible when the respiratory system is insufflated with positive end-expiratory pressure. Under dynamic conditions, moving this structure demands a pressure change whose magnitude is related to its mechanical characteristics, and this load remains constant regardless of the volume from which it is insufflated. Thus, changes in airway pressure reflect changes in the lung mechanical conditions. Advanced monitoring could be reserved for patients with increased intra-abdominal pressure in whom a protective mechanical ventilation strategy cannot be implemented. The estimates of alveolar recruitment based on respiratory system mechanics could reflect differences in chest wall response to insufflation and not actual alveolar recruitment.
La mecánica del sistema respiratorio depende de las características del pulmón, la caja torácica y su interacción. En pacientes con síndrome de distrés respiratorio agudo bajo ventilación mecánica el monitoreo de la presión meseta en la vía aérea es fundamental debido a su valor pronóstico y su capacidad de reflejar el estrés pulmonar. Sin embargo, su validez puede verse afectada por cambios en las características mecánicas de la caja torácica, y además, no otorga información para la correcta titulación de presión positiva al final de la espiración en función de restablecer el volumen pulmonar. La influencia que la caja torácica ejerce sobre la mecánica del sistema respiratorio en síndrome de distrés respiratorio agudo no ha sido completamente descripta y es probable que haya sido sobredimensionada pudiendo conducir a toma de decisiones erróneas. Ante la insuflación con presión positiva al final de la espiración, la carga impuesta por la caja torácica es despreciable. En condiciones dinámicas, desplazar esta estructura demanda un cambio de presión cuya magnitud se relaciona con sus características mecánicas, dicha carga se mantiene constante independientemente del volumen a partir del cual es insuflada. Por lo que cambios en la presión en la vía aérea reflejan modificaciones en las condiciones mecánicas del pulmón. El monitoreo avanzado podría reservarse para pacientes con incremento de la presión intra-abdominal en los que no pueda implementarse una estrategia de ventilación mecánica protectora. Las estimaciones de reclutamiento alveolar basadas en la mecánica del sistema respiratorio podrían ser reflejo del diferente comportamiento de la caja torácica a la insuflación y no verdadero reclutamiento alveolar.
Assuntos
Respiração Artificial/métodos , Síndrome do Desconforto Respiratório/cirurgia , Síndrome do Desconforto Respiratório/terapia , Mecânica Respiratória/fisiologia , Humanos , Monitorização Fisiológica/métodos , Respiração com Pressão Positiva , Prognóstico , Alvéolos Pulmonares/metabolismo , Síndrome do Desconforto Respiratório/fisiopatologia , Parede Torácica/metabolismo , Volume de Ventilação Pulmonar/fisiologiaRESUMO
RESUMEN La mecánica del sistema respiratorio depende de las características del pulmón, la caja torácica y su interacción. En pacientes con síndrome de distrés respiratorio agudo bajo ventilación mecánica el monitoreo de la presión meseta en la vía aérea es fundamental debido a su valor pronóstico y su capacidad de reflejar el estrés pulmonar. Sin embargo, su validez puede verse afectada por cambios en las características mecánicas de la caja torácica, y además, no otorga información para la correcta titulación de presión positiva al final de la espiración en función de restablecer el volumen pulmonar. La influencia que la caja torácica ejerce sobre la mecánica del sistema respiratorio en síndrome de distrés respiratorio agudo no ha sido completamente descripta y es probable que haya sido sobredimensionada pudiendo conducir a toma de decisiones erróneas. Ante la insuflación con presión positiva al final de la espiración, la carga impuesta por la caja torácica es despreciable. En condiciones dinámicas, desplazar esta estructura demanda un cambio de presión cuya magnitud se relaciona con sus características mecánicas, dicha carga se mantiene constante independientemente del volumen a partir del cual es insuflada. Por lo que cambios en la presión en la vía aérea reflejan modificaciones en las condiciones mecánicas del pulmón. El monitoreo avanzado podría reservarse para pacientes con incremento de la presión intra-abdominal en los que no pueda implementarse una estrategia de ventilación mecánica protectora. Las estimaciones de reclutamiento alveolar basadas en la mecánica del sistema respiratorio podrían ser reflejo del diferente comportamiento de la caja torácica a la insuflación y no verdadero reclutamiento alveolar.
ABSTRACT The respiratory system mechanics depend on the characteristics of the lung and chest wall and their interaction. In patients with acute respiratory distress syndrome under mechanical ventilation, the monitoring of airway plateau pressure is fundamental given its prognostic value and its capacity to assess pulmonary stress. However, its validity can be affected by changes in mechanical characteristics of the chest wall, and it provides no data to correctly titrate positive end-expiratory pressure by restoring lung volume. The chest wall effect on respiratory mechanics in acute respiratory distress syndrome has not been completely described, and it has likely been overestimated, which may lead to erroneous decision making. The load imposed by the chest wall is negligible when the respiratory system is insufflated with positive end-expiratory pressure. Under dynamic conditions, moving this structure demands a pressure change whose magnitude is related to its mechanical characteristics, and this load remains constant regardless of the volume from which it is insufflated. Thus, changes in airway pressure reflect changes in the lung mechanical conditions. Advanced monitoring could be reserved for patients with increased intra-abdominal pressure in whom a protective mechanical ventilation strategy cannot be implemented. The estimates of alveolar recruitment based on respiratory system mechanics could reflect differences in chest wall response to insufflation and not actual alveolar recruitment.
Assuntos
Humanos , Respiração Artificial/métodos , Síndrome do Desconforto Respiratório/cirurgia , Síndrome do Desconforto Respiratório/terapia , Mecânica Respiratória/fisiologia , Prognóstico , Alvéolos Pulmonares/metabolismo , Síndrome do Desconforto Respiratório/fisiopatologia , Volume de Ventilação Pulmonar/fisiologia , Respiração com Pressão Positiva , Parede Torácica/metabolismo , Monitorização Fisiológica/métodosRESUMO
Background Sclerotherapy has been gaining increased acceptance and popularity as an effective therapy for the treatment of varicose veins. This attention has fed growing interest into the safety and potential complications of this procedure. There is no evidence of pulmonary complications from foam sclerotherapy in humans; however, animal studies have shown possible damage. The aim of this study is to show the changes in rat pulmonary parenchyma after the injection of 1% polidocanol Tessari foam into the peripheral vein using histological analysis of the inflammatory and fibrosis processes. Methods Twenty-four Wistar rats were divided into the following four groups: 24 h polidocanol, seven-day polidocanol, 28-day polidocanol, and control group. After the foam was injected into the lateral saphenous vein, the lungs of the rats were removed for histological analysis. Results Alveolar edema was observed in only the 24 h group (P < 0.005). Vessel thickening was observed in the seven-and 28-day groups (P < 0.001). Interstitial fibrosis was found in only the 28-day group (P = 0.006). There was no evidence of venous or arterial thrombosis in either group. Conclusion Polidocanol Tessari foam injection into rat peripheral veins causes alveolar edema, vessel thickening, and interstitial fibrosis.