Minimally invasive lung tissue differentiation using electrical impedance spectroscopy: a comparison of the 3- and 4-electrode methods

Multiple imaging techniques are used for the diagnosis of lung diseases. The choice of a technique depends on the suspected diagnosis. Computed tomography (CT) of the thorax and positron emission tomography (PET) are imaging techniques used for the detection, characterization, staging and follow-up of lung cancer, and these techniques use ionizing radiation and are radiologist-dependent. Electrical impedance spectroscopy (EIS) performed through a bronchoscopic process could serve as a minimally invasive non-ionizing method complementary to CT and PET to characterize lung tissue. The aim of this study was to analyse the feasibility and ability of minimally invasive EIS bioimpedance measures to differentiate among healthy lung, bronchial and neoplastic lung tissues through bronchoscopy using the 3- and 4-electrode methods. Tissue differentiation was performed in 13 patients using the 4-electrode method (13 healthy lung, 12 bronchial and 3 neoplastic lung tissues) and the 3-electrode method (9 healthy lung, 10 bronchial and 2 neoplastic lung tissues). One-way analysis of variance (ANOVA) showed a statistically significant difference (P < 0.001) between bronchial and healthy lung tissues for both the 3- and 4-electrode methods. The 3-electrode method seemed to differentiate cancer types through changes in the cellular structures of the tissues by both the reactance (Xc) and the resistance (R). Minimally invasive measurements obtained using the 3-electrode method seem to be most suitable for differentiating between healthy and bronchial lung tissues. In the future, EIS using the 3-electrode method could be a method complementary to PET/CT and biopsy in lung pathology diagnosis.Peer ReviewedPostprint (author's final draft

Effect of calibration for tissue differentiation between healthy and neoplasm lung using minimally invasive electrical impedance spectroscopy

his study proposes a calibration method and analyses the effect of this calibration in lung measures, using minimally invasive electrical impedance spectroscopy with the 3-electrode method, for tissue differentiation between healthy and neoplasm lung tissue. Tissue measurements were performed in 99 patients [54 healthy tissue and 15 neoplastic tissue samples obtained] with an indicated bronchoscopy. Statistically significant difference (P < 0.001) were found between healthy lung tissue and neoplasm lung tissue in bioimpedance parameters. The calibration of the bioimpedance measures with respect to a measure performed in bronchi reduces the inter-patient dispersion, increasing the sensitivity, decreasing the specificity and increasing the area below the ROC curve for three out of four impedance-derived estimators. Results also show that there are no significant differences between healthy lung tissue among smoker, non-smoker and ex-smoker samples, which was initially stated as a possible cause of EIS measurement dispersion in lungs.Peer ReviewedPostprint (published version

Using temporal electrical impedance spectroscopy measures to differentiate lung pathologies with the 3-electrode method

Minimally invasive lung bioimpedance measurements could serve in the future diagnosis of lung pathologies complementing biopsies and imaging techniques. Through the electrical impedance spectroscopy (EIS) technique using the 3-electrode method, distinction of lung pathologies could be possible depending on the state of the tissue. Since now, only averaged information has been used for the analysis of bioimpedance data in lungs. The aim of this study is to use temporal information to evaluate changes in the impedance signal due to the mechanism of ventilation and perfusion produced by the lungs. Preliminary results show: 1) correlation between ventilation and perfusion with the bioimpedance signal and 2) changes in the amplitude of the bioimpedance time signal depending on the pathology. As conclusion, together with cycled averaged data, temporal data could be useful for lung pathologies distinction.Postprint (published version

Differentiation using minimally-invasive bioimpedance measurements of healthy and pathological lung tissue through bronchoscopy

Purpose: To use minimally-invasive transcatheter electrical impedance spectroscopy measurements for tissue differentiation among healthy lung tissue and pathologic lung tissue from patients with different respiratory diseases (neoplasm, fibrosis, pneumonia and emphysema) to complement the diagnosis at real time during bronchoscopic procedures. Methods: Multi-frequency bioimpedance measurements were performed in 102 patients. The two most discriminative frequencies for impedance modulus (|Z|), phase angle (PA), resistance (R) and reactance (Xc) were selected based on the maximum mean pair-wise Euclidean distances between paired groups. One-way ANOVA for parametric variables and Kruskal–Wallis for non-parametric data tests have been performed with post-hoc tests. Discriminant analysis has also been performed to find a linear combination of features to separate among tissue groups. Results: We found statistically significant differences for all the parameters between: neoplasm and pneumonia (p¿¿0.05) are found between neoplasm and fibrosis; fibrosis and pneumonia; and between healthy lung tissue and emphysema. Conclusion: The application of minimally-invasive electrical impedance spectroscopy measurements in lung tissue have proven to be useful for tissue differentiation between those pathologies that leads increased tissue and inflammatory cells and those ones that contain more air and destruction of alveolar septa, which could help clinicians to improve diagnosis.Peer ReviewedPostprint (published version

Experimental supporting data on the influence of platelet-derived factors of malignant pleural effusions on T cell effector functions and their relevance in predicting prognosis of lung adenocarcinoma patients with pleural metastasis

The data described in this article are supplementary to our primary article "Platelet factor 4 regulates T cell effector functions in malignant pleural effusions". Malignant pleural effusion (MPE) is a common complication of advanced lung adenocarcinoma (LAC) associated with a poor life expectancy [1]. Several challenges need to be addressed to identify non-invasive molecular biomarkers that help to predict the prognosis of LAC patients with MPE [2]. In the primary publication, we proposed that platelet-derived factors, especially platelet factor 4 (PF4), can negatively regulate T lymphocyte activation and granzyme B expression in pleural metastasis and its levels were associated with a worse prognosis. Here, we provide data on the influence of other platelet-derived factors, including transforming growth factor β (TGF-β), vascular endothelial factor (VEGF), and P-selectin on T lymphocyte response in MPE and their relevance as prognostic factors in lung cancer patients with pleural metastasis. Pleural fluids from 35 lung adenocarcinoma (LAC) and 20 heart failure (HF) patients were collected by thoracentesis and its platelet-derived factors' content was measured by specific enzyme-linked immunosorbent assay (ELISAs). Correlations between pleural levels of platelet-derived factors and T cell functions were analyzed by Pearson coefficients. Kaplan-Meier curves were used to estimate the effect of pleural concentrations of platelet-derived factors on overall survival of LAC patients with pleural metastasis. These analyses showed that the concentration of platelet-derived factors was not associated with T cell proliferation and cytotoxicity. Furthermore, their levels do not predict the survival of LAC with MPE

Influence of Malignant Pleural Fluid from Lung Adenocarcinoma Patients on Neutrophil Response

Altres ajuts: Merck KGaA, Darmstadt, Germany; Fondo de Investigaciones Sanitarias (FIS).Malignant pleural effusion (MPE) is a common severe complication of advanced lung ad-enocarcinoma (LAC). Neutrophils, an essential component of tumor infiltrates, contribute to tumor progression and their counts in MPE have been associated with worse outcome in LAC. This study aimed to evaluate phenotypical and functional changes of neutrophils induced by MPE to determine the influence of MPE immunomodulatory factors in neutrophil response and to find a possible association between neutrophil functions and clinical outcomes. Pleural fluid samples were col-lected from 47 LAC and 25 heart failure (HF) patients. We measured neutrophil degranulation products by ELISA, oxidative burst capacity and apoptosis by flow cytometry, and NETosis by fluores-cence. The concentration of degranulation products was higher in MPE-LAC than in PE-HF. Func-tionally, neutrophils cultured with MPE-LAC had enhanced survival and neutrophil extracellular trap (NET) formation but had reduced oxidative burst capacity. In MPE, NETosis was positively associated with MMP-9, P-selectin, and sPD-L1 and clinically related to a worse outcome. This is the first study associating NETs with a worse outcome in MPE. Neutrophils likely contribute to tumor progression through the release of NETs, suggesting that they are a potential therapeutic target in LAC

Hepatic levels of S-adenosylmethionine regulate the adaptive response to fasting

26 p.-6 fig.-1 tab.-1 graph. abst.There has been an intense focus to uncover the molecular mechanisms by which fasting triggers the adaptive cellular responses in the major organs of the body. Here, we show that in mice, hepatic S-adenosylmethionine (SAMe)—the principal methyl donor—acts as a metabolic sensor of nutrition to fine-tune the catabolic-fasting response by modulating phosphatidylethanolamine N-methyltransferase (PEMT) activity, endoplasmic reticulum-mitochondria contacts, β-oxidation, and ATP production in the liver, together with FGF21-mediated lipolysis and thermogenesis in adipose tissues. Notably, we show that glucagon induces the expression of the hepatic SAMe-synthesizing enzyme methionine adenosyltransferase α1 (MAT1A), which translocates to mitochondria-associated membranes. This leads to the production of this metabolite at these sites, which acts as a brake to prevent excessive β-oxidation and mitochondrial ATP synthesis and thereby endoplasmic reticulum stress and liver injury. This work provides important insights into the previously undescribed function of SAMe as a new arm of the metabolic adaptation to fasting.M.V.-R. is supported by Proyecto PID2020-119486RB-100 (funded by MCIN/AEI/10.13039/501100011033), Gilead Sciences International Research Scholars Program in Liver Disease, Acción Estratégica Ciberehd Emergentes 2018 (ISCIII), Fundación BBVA, HORIZON-TMA-MSCA-Doctoral Networks 2021 (101073094), and Redes de Investigación 2022 (RED2022-134485-T). M.L.M.-C. is supported by La CAIXA Foundation (LCF/PR/HP17/52190004), Proyecto PID2020-117116RB-I00 (funded by MCIN/AEI/10.13039/501100011033), Ayudas Fundación BBVA a equipos de investigación científica (Umbrella 2018), and AECC Scientific Foundation (Rare Cancers 2017). A.W. is supported by RTI2018-097503-B-I00 and PID2021-127169OB-I00, (funded by MCIN/AEI/10.13039/501100011033) and by “ERDF A way of making Europe,” Xunta de Galicia (Ayudas PRO-ERC), Fundación Mutua Madrileña, and European Community’s H2020 Framework Programme (ERC Consolidator grant no. 865157 and MSCA Doctoral Networks 2021 no. 101073094). C.M. is supported by CIBERNED. P.A. is supported by Ayudas para apoyar grupos de investigación del sistema Universitario Vasco (IT1476-22), PID2021-124425OB-I00 (funded by MCIN/AEI/10.13039/501100011033 and “ERDF A way of making Europe,” MCI/UE/ISCiii [PMP21/00080], and UPV/EHU [COLAB20/01]). M.F. and M.G.B. are supported by PID2019-105739GB-I00 and PID2020-115472GB-I00, respectively (funded by MCIN/AEI/10.13039/501100011033). M.G.B. is supported by Xunta de Galicia (ED431C 2019/013). C.A., T.L.-D., and J.B.-V. are recipients of pre-doctoral fellowships from Xunta de Galicia (ED481A-2020/046, ED481A-2018/042, and ED481A 2021/244, respectively). T.C.D. is supported by Fundación Científica AECC. A.T.-R. is a recipient of a pre-doctoral fellowship from Fundación Científica AECC. S.V.A. and C.R. are recipients of Margarita Salas postdoc grants under the “Plan de Recuperación Transformación” program funded by the Spanish Ministry of Universities with European Union’s NextGeneration EU funds (2021/PER/00020 and MU-21-UP2021-03071902373A, respectively). T.C.D., A.S.-R., and M.T.-C. are recipients of Ayuda RYC2020-029316-I, PRE2019/088960, and BES-2016/078493, respectively, supported by MCIN/AEI/10.13039/501100011033 and by El FSE invierte en tu futuro. S.L.-O. is a recipient of a pre-doctoral fellowship from the Departamento de Educación del Gobierno Vasco (PRE_2018_1_0372). P.A.-G. is recipient of a FPU pre-doctoral fellowship from the Ministry of Education (FPU19/02704). CIC bioGUNE is supported by Ayuda CEX2021-001136-S financiada por MCIN/AEI/10.13039/501100011033. A.B.-C. was funded by predoctoral contract PFIS (FI19/00240) from Instituto de Salud Carlos III (ISCIII) co-funded by Fondo Social Europeo (FSE), and A.D.-L. was funded by contract Juan Rodés (JR17/00016) from ISCIII. A.B.-C. is a Miguel Servet researcher (CPII22/00008) from ISCIII.Peer reviewe

Utilización de criosondas para la realización de la biopsia pulmonar transbronquial

La biopsia pulmonar transbronquial es una técnica broncoscópica indicada en el estudio de las enfermedades pulmonares difusas. Hasta el momento, la técnica diagnóstica utilizada para la obtención de muestras pulmonares de una forma no quirúrgica es la biopsia pulmonar transbronquial con pinza convencional, pero tal y como se detalla en la presente exposición, el rendimiento diagnóstico de esta técnica es limitado y variable. Esta variabilidad es debida, entre otros factores, al pequeño tamaño de las biopsias y a la presencia de artefactos que alteran la calidad de las muestras. La línea de investigación desarrollada tiene como objetivo ampliar las herramientas diagnósticas actualmente disponibles en broncoscopia con la aplicación de una técnica innovadora basada en la utilización de sondas de crioterapia que permiten realizar la biopsia transbronquial de una forma ambulatoria y menos invasiva que otras alternativas actualmente disponibles como la biopsia quirúrgica. Los dos trabajos presentados en esta tesis evalúan la utilización de criosondas para la obtención de parénquima pulmonar como una alternativa diagnóstica a la biopsia pulmonar transbronquial convencional. Ambos estudios se llevaron a cabo en pacientes con sospecha de enfermedad intersticial difusa. En primer lugar, se presentan los resultados de una primera fase prospectiva que ha permitido valorar la viabilidad de la técnica y su aplicación en nuestro medio así como, la descripción de la metodología. En una segunda fase, se analizan los resultados de un ensayo clínico aleatorizado para evaluar el rendimiento diagnóstico del nuevo procedimiento en comparación con la técnica convencional. Los resultados de los trabajos publicados indican que la realización de la biopsia pulmonar transbronquial con criosonda posibilita la mejora en el manejo diagnóstico de los pacientes con determinadas patologías pulmonares, especialmente en el grupo de las enfermedades pulmonares difusas y, actualmente, se ha comenzado a considerar un procedimiento más en el algoritmo diagnóstico de estas enfermedades.Transbronchial lung biopsy (TBLB) is a bronchoscopic procedure for obtaining material in the diagnosis of diffuse interstitial lung disease. To date, conventional forceps have usually been used to sample tissue in this nonsurgical approach, but the diagnostic yield of TBLB has been limited and variable, as shown by the literature reviewed for this thesis. Variability in the yield of conventional-forceps TBLB can be attributed to the small size of the samples obtained and to the presence of artifacts, among other factors. The line of research presented here aimed to extend the range of bronchoscopic diagnostic tools to include the innovative use of cryoprobes for harvesting tissue. The transbronchial cryobiopsy technique described can be performed as an outpatient procedure and is less invasive than open lung biopsy. Two studies were undertaken to evaluate cryoprobe sampling of the lung parenchyma as an alternative to conventional-forceps TBLB. Both studies were carried out in patients with suspected diffuse interstitial disease. I first present the findings of a prospective study of the cryoprobe technique to assess its viability in a Spanish teaching hospital. In this part of the thesis, the technique is described in detail. Next, I analyze the results of a randomized clinical trial that compared the diagnostic yield of the new cryoprobe procedure to the yield of conventional-forceps TBLB. The studies showed that transbronchial cryobiopsy facilitates the diagnostic process in certain lung conditions, particularly diffuse interstitial lung diseases. When these entities are suspected, transbronchial cryobiopsy is increasingly being included in diagnostic protocols

Utilización de criosondas para la realización de la biopsia pulmonar transbronquial

La biopsia pulmonar transbronquial es una técnica broncoscópica indicada en el estudio de las enfermedades pulmonares difusas. Hasta el momento, la técnica diagnóstica utilizada para la obtención de muestras pulmonares de una forma no quirúrgica es la biopsia pulmonar transbronquial con pinza convencional, pero tal y como se detalla en la presente exposición, el rendimiento diagnóstico de esta técnica es limitado y variable. Esta variabilidad es debida, entre otros factores, al pequeño tamaño de las biopsias y a la presencia de artefactos que alteran la calidad de las muestras. La línea de investigación desarrollada tiene como objetivo ampliar las herramientas diagnósticas actualmente disponibles en broncoscopia con la aplicación de una técnica innovadora basada en la utilización de sondas de crioterapia que permiten realizar la biopsia transbronquial de una forma ambulatoria y menos invasiva que otras alternativas actualmente disponibles como la biopsia quirúrgica. Los dos trabajos presentados en esta tesis evalúan la utilización de criosondas para la obtención de parénquima pulmonar como una alternativa diagnóstica a la biopsia pulmonar transbronquial convencional. Ambos estudios se llevaron a cabo en pacientes con sospecha de enfermedad intersticial difusa. En primer lugar, se presentan los resultados de una primera fase prospectiva que ha permitido valorar la viabilidad de la técnica y su aplicación en nuestro medio así como, la descripción de la metodología. En una segunda fase, se analizan los resultados de un ensayo clínico aleatorizado para evaluar el rendimiento diagnóstico del nuevo procedimiento en comparación con la técnica convencional. Los resultados de los trabajos publicados indican que la realización de la biopsia pulmonar transbronquial con criosonda posibilita la mejora en el manejo diagnóstico de los pacientes con determinadas patologías pulmonares, especialmente en el grupo de las enfermedades pulmonares difusas y, actualmente, se ha comenzado a considerar un procedimiento más en el algoritmo diagnóstico de estas enfermedades.Transbronchial lung biopsy (TBLB) is a bronchoscopic procedure for obtaining material in the diagnosis of diffuse interstitial lung disease. To date, conventional forceps have usually been used to sample tissue in this nonsurgical approach, but the diagnostic yield of TBLB has been limited and variable, as shown by the literature reviewed for this thesis. Variability in the yield of conventional-forceps TBLB can be attributed to the small size of the samples obtained and to the presence of artifacts, among other factors. The line of research presented here aimed to extend the range of bronchoscopic diagnostic tools to include the innovative use of cryoprobes for harvesting tissue. The transbronchial cryobiopsy technique described can be performed as an outpatient procedure and is less invasive than open lung biopsy. Two studies were undertaken to evaluate cryoprobe sampling of the lung parenchyma as an alternative to conventional-forceps TBLB. Both studies were carried out in patients with suspected diffuse interstitial disease. I first present the findings of a prospective study of the cryoprobe technique to assess its viability in a Spanish teaching hospital. In this part of the thesis, the technique is described in detail. Next, I analyze the results of a randomized clinical trial that compared the diagnostic yield of the new cryoprobe procedure to the yield of conventional-forceps TBLB. The studies showed that transbronchial cryobiopsy facilitates the diagnostic process in certain lung conditions, particularly diffuse interstitial lung diseases. When these entities are suspected, transbronchial cryobiopsy is increasingly being included in diagnostic protocols