Regional and organ-level responses to local lung irradiation in sheep

Abstract Lung is a dose-limiting organ in radiotherapy. This may limit tumour control when effort is made in planning to limit the likelihood of radiation-induced lung injury (RILI). Understanding the factors that dictate susceptibility to radiation-induced pulmonary fibrosis will aid in the prevent...

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Autores principales:	David Collie, Steven H. Wright, Jorge del-Pozo, Elaine Kay, Tobias Schwarz, Magdalena Parys, Jessica Lawrence
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2021
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/0c5d94e24c0d4d5098fd5b1fbe29f23e
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spelling	oai:doaj.org-article:0c5d94e24c0d4d5098fd5b1fbe29f23e2021-12-02T14:42:52ZRegional and organ-level responses to local lung irradiation in sheep10.1038/s41598-021-88863-82045-2322https://doaj.org/article/0c5d94e24c0d4d5098fd5b1fbe29f23e2021-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-021-88863-8https://doaj.org/toc/2045-2322Abstract Lung is a dose-limiting organ in radiotherapy. This may limit tumour control when effort is made in planning to limit the likelihood of radiation-induced lung injury (RILI). Understanding the factors that dictate susceptibility to radiation-induced pulmonary fibrosis will aid in the prevention and management of RILI, and may lead to more effective personalized radiotherapy treatment. As the interaction of regional and organ-level responses may shape the chronic consequences of RILI, we sought to characterise both aspects of the response in an ovine model. A defined volume of left pulmonary parenchyma was prescribed 5 fractions of 6 Gy within 14 days while the contralateral lung dose was constrained. Radiographic changes via computed tomography (CT) were documented to define differences in radio-exposed lung relative to non-exposed lung at d21, d63 and d171 (n = 2), and at d21, d147 and d227 (n = 2). Gross and histologic lung changes were evaluated in samples derived at necropsy examination to define the chronic pulmonary response to radiation. Irradiated lung demonstrated reduced radio-density and increased homogeneity as evidenced from texture based radiomic feature analysis, relative to the control lung. At necropsy, the radiation field was readily defined by pallor on the pleural surface, which was also evident on the cut surface of fixed lung specimens. The degree and homogeneity of pallor reflected the sparse presence of erythrocytes in alveolar septal capillaries of radiation-exposed lung. These changes contrasted with dilated and congested microvasculature in the contralateral control lung. Referencing data to measurements made in control lung volumes of sheep experiencing acute RILI indicated that interstitial collagen continues to deposit in the radio-exposed lung field. Overall lung vascularity increased during the chronic response, as evidenced by increased expression of endothelial cell marker (CD31); however, vascularity was consistently decreased in irradiated lung and was negatively correlated with lung collagen. Other organ-level responses included increased expression of alpha smooth muscle actin (ASMA), increased numbers of proliferating cells (Ki67 positive), and cells expressing the dendritic cell-lysosomal associated membrane protein (DC-LAMP) antigen. The chronic response to RILI in this model is effected at both the whole organ and local lung level. Whilst the long-term consequences of exposure to radiation involved the continued deposition of collagen in the radiation field, organ-level responses also included increased vascularization and increased expression of ASMA, Ki67 and DC-LAMP. Interrupting the interplay between these aspects may influence susceptibility to pulmonary fibrosis after radiotherapy. We advocate for the importance of large animal model systems in pursuing these opportunities to target local, organ-level and systemic mechanisms in parallel within the same subject over time.David CollieSteven H. WrightJorge del-PozoElaine KayTobias SchwarzMagdalena ParysJessica LawrenceNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 11, Iss 1, Pp 1-16 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q David Collie Steven H. Wright Jorge del-Pozo Elaine Kay Tobias Schwarz Magdalena Parys Jessica Lawrence Regional and organ-level responses to local lung irradiation in sheep
description	Abstract Lung is a dose-limiting organ in radiotherapy. This may limit tumour control when effort is made in planning to limit the likelihood of radiation-induced lung injury (RILI). Understanding the factors that dictate susceptibility to radiation-induced pulmonary fibrosis will aid in the prevention and management of RILI, and may lead to more effective personalized radiotherapy treatment. As the interaction of regional and organ-level responses may shape the chronic consequences of RILI, we sought to characterise both aspects of the response in an ovine model. A defined volume of left pulmonary parenchyma was prescribed 5 fractions of 6 Gy within 14 days while the contralateral lung dose was constrained. Radiographic changes via computed tomography (CT) were documented to define differences in radio-exposed lung relative to non-exposed lung at d21, d63 and d171 (n = 2), and at d21, d147 and d227 (n = 2). Gross and histologic lung changes were evaluated in samples derived at necropsy examination to define the chronic pulmonary response to radiation. Irradiated lung demonstrated reduced radio-density and increased homogeneity as evidenced from texture based radiomic feature analysis, relative to the control lung. At necropsy, the radiation field was readily defined by pallor on the pleural surface, which was also evident on the cut surface of fixed lung specimens. The degree and homogeneity of pallor reflected the sparse presence of erythrocytes in alveolar septal capillaries of radiation-exposed lung. These changes contrasted with dilated and congested microvasculature in the contralateral control lung. Referencing data to measurements made in control lung volumes of sheep experiencing acute RILI indicated that interstitial collagen continues to deposit in the radio-exposed lung field. Overall lung vascularity increased during the chronic response, as evidenced by increased expression of endothelial cell marker (CD31); however, vascularity was consistently decreased in irradiated lung and was negatively correlated with lung collagen. Other organ-level responses included increased expression of alpha smooth muscle actin (ASMA), increased numbers of proliferating cells (Ki67 positive), and cells expressing the dendritic cell-lysosomal associated membrane protein (DC-LAMP) antigen. The chronic response to RILI in this model is effected at both the whole organ and local lung level. Whilst the long-term consequences of exposure to radiation involved the continued deposition of collagen in the radiation field, organ-level responses also included increased vascularization and increased expression of ASMA, Ki67 and DC-LAMP. Interrupting the interplay between these aspects may influence susceptibility to pulmonary fibrosis after radiotherapy. We advocate for the importance of large animal model systems in pursuing these opportunities to target local, organ-level and systemic mechanisms in parallel within the same subject over time.
format	article
author	David Collie Steven H. Wright Jorge del-Pozo Elaine Kay Tobias Schwarz Magdalena Parys Jessica Lawrence
author_facet	David Collie Steven H. Wright Jorge del-Pozo Elaine Kay Tobias Schwarz Magdalena Parys Jessica Lawrence
author_sort	David Collie
title	Regional and organ-level responses to local lung irradiation in sheep
title_short	Regional and organ-level responses to local lung irradiation in sheep
title_full	Regional and organ-level responses to local lung irradiation in sheep
title_fullStr	Regional and organ-level responses to local lung irradiation in sheep
title_full_unstemmed	Regional and organ-level responses to local lung irradiation in sheep
title_sort	regional and organ-level responses to local lung irradiation in sheep
publisher	Nature Portfolio
publishDate	2021
url	https://doaj.org/article/0c5d94e24c0d4d5098fd5b1fbe29f23e
work_keys_str_mv	AT davidcollie regionalandorganlevelresponsestolocallungirradiationinsheep AT stevenhwright regionalandorganlevelresponsestolocallungirradiationinsheep AT jorgedelpozo regionalandorganlevelresponsestolocallungirradiationinsheep AT elainekay regionalandorganlevelresponsestolocallungirradiationinsheep AT tobiasschwarz regionalandorganlevelresponsestolocallungirradiationinsheep AT magdalenaparys regionalandorganlevelresponsestolocallungirradiationinsheep AT jessicalawrence regionalandorganlevelresponsestolocallungirradiationinsheep
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Regional and organ-level responses to local lung irradiation in sheep

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