Changes in surfactant in bronchoalveolar lavage fluid after hemithorax irradiation in patients with mesothelioma

Our plain-English summary of Changes in surfactant in bronchoalveolar lavage fluid after hemithorax irradiation in patients with mesothelioma, by M. Hallman, P. Maasilta, L. Kivisaari, et al (The American Review of Respiratory Disease, 1990).

The study

• Authors: M. Hallman, P. Maasilta, L. Kivisaari, K. Mattson
• Journal: The American Review of Respiratory Disease
• Published: 1990;141(4 Pt 1):998-1005
• Cited by: 40 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Experimental studies have shown that the surfactant system of the lung is affected shortly after irradiation. It is unclear, however, whether surfactant plays a role in the pathogenesis of radiation pneumonitis. In the present study surfactant components (saturated phosphatidylcholine, surfactant protein A, phosphatidylglycerol, and phosphatidylinositol) and other phospholipids of bronchoalveolar lavage fluid (BAL) were studied in four patients with pleural mesothelioma before and during hemithorax irradiation (70 Gy) as well as zero, 1, 2, 3, and 4 months following irradiation. The concentrations of these same components and of soluble proteins were also estimated in the epithelial lining fluid (ELF) using urea as a marker of dilution. After radiotherapy, the concentrations of the surfactant components in ELF decreased to 12 to 55% of the control values before radiation, whereas the concentration of sphingomyelin in ELF increased ninefold. There were small changes in the other phospholipids. The concentration of soluble protein in ELF increased sevenfold. The minimum surface activity of crude BAL increased from 12 +/- 4 to 32 +/- 6 mN/m, and that of the sediment fraction of BAL increased from 7 +/- 4 to 22 +/- 6 mN/m, p less than 0.001. The protein-rich supernatant fraction of BAL from irradiated lung had a inhibitory effect on normal surfactant. There were significant correlations between the increasing severity of the radiologic changes on the one hand and, on the other, the saturated phosphatidylcholine/sphingomyelin ratio (p less than 0.001), the concentrations of soluble protein (p less than 0.001), and the concentrations of the surfactant components (p less than 0.02-0.001) in ELF.(ABSTRACT TRUNCATED AT 250 WORDS)

In plain English

This study followed four patients in Finland with malignant pleural mesothelioma (epithelial subtype). Each received radiation to one side of the chest (hemithorax irradiation, 70 Gy over 7 weeks) after chemotherapy and debulking surgery that removed part of the affected pleura. The study examined radiation effects on the lung's surfactant system, not asbestos. Before, during and up to 4 months after radiation, the authors washed out a segment of the irradiated lung (bronchoalveolar lavage) to measure surfactant and protein. After radiation, surfactant components in the lung lining fluid fell to 12 to 55% of their pre-radiation values, sphingomyelin rose ninefold and soluble protein rose sevenfold. Minimum surface tension of the lavage fluid rose from 12 ± 4 to 32 ± 6 mN/m. In laboratory tests, fluid from irradiated lungs inhibited normal surfactant. The biochemical surfactant and protein measures in the lining fluid correlated significantly with worsening lung damage on CT scans. All four developed persistent cough and breathlessness, and in all four the irradiated lung eventually showed no normal lung tissue. The authors concluded that the surfactant and protein changes may play a role in radiation-induced lung injury.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Small clinical case series: four patients with repeated bronchoalveolar lavage, lung function tests and CT scans before, during and after radiotherapy
• Who was studied: Four patients (one woman, three men, aged 52 to 70) with histologically confirmed malignant pleural mesothelioma of epithelial subtype, clinical stage I (two) or IIA (two), treated at the University of Helsinki / Helsinki University Central Hospital, Finland. The study dates are not given.
• Exposure: Hemithorax irradiation to a total dose of 70 Gy (24 MeV photons, 56 fractions of 1.25 Gy twice daily over 7 weeks). It was given after debulking surgery (subtotal resection of the involved pleura) and chemotherapy. Asbestos exposure was recorded only as a patient characteristic and was not the exposure studied.
• Main results:
  • In the four patients, surfactant components in the epithelial lining fluid fell after radiotherapy to 12 to 55% of pre-radiation values, while sphingomyelin increased ninefold
  • Soluble protein in the epithelial lining fluid increased sevenfold after radiotherapy
  • Minimum surface tension of crude lavage fluid rose from 12 ± 4 to 32 ± 6 mN/m, and that of the sediment fraction rose from 7 ± 4 to 22 ± 6 mN/m (p less than 0.001)
  • In laboratory testing, the protein-rich fraction of lavage fluid from irradiated lung inhibited normal surfactant
  • The biochemical surfactant indices and the protein concentration in the lining fluid correlated significantly with increasing severity of CT changes. They also correlated (p less than 0.05) with deterioration of lung function.
  • All four patients developed persistent cough and mild to moderate dyspnea starting 1 month after radiotherapy
  • In all four patients, the final outcome of the radiation injury on CT was a total lack of normal lung tissue
• The authors' conclusion: The authors concluded that hemithorax irradiation caused protein accumulation in the air spaces, inactivation of surfactant and a fall in surfactant components in the lining fluid. They concluded that these changes may play a role in radiation-induced lung injury.
• Limitations the authors state:
  • Segmental lavage does not accurately estimate the amount of phospholipids in the airways
  • Lavage was done only once during treatment and monthly afterward, so an early increase in phospholipid secretion could not be excluded
  • The lavage protocol may underestimate surfactant and soluble protein concentrations in the lining fluid
  • Lavage was not feasible beyond 4 months after radiotherapy

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma.

Medical terms in this study, explained in our Lexicon: Bronchoalveolar Lavage (BAL), Hemithorax, Mesothelioma, Pneumonitis, Pleural Mesothelioma.

Related studies

• Different imaging methods in the assessment of radiation-induced lung injury following hemithorax irradiation for pleural mesothelioma — P. Maasilta, L. Kivisaari, et al. (1990)
• Detection of lipid peroxidation in lung and in bronchoalveolar lavage cells and fluid — J.M. Petruska, S.H. Wong, et al. (1990)
• Chrysotile-induced asbestosis: changes in the free cell population, pulmonary surfactant and whole lung tissue of rats — T.D. Tetley, P.M. Hext, et al. (1976)
• Pleural plaques, asbestos exposure, and asbestos bodies in bronchoalveolar lavage fluid — E. Orlowski, J.C. Pairon, et al. (1994)
• Clara cell protein (CC-16) and surfactant-associated protein A (SP-A) in asbestos-exposed workers — O. Lesur, A.M. Bernard, et al. (1996)
• Diagnostic value of asbestos bodies in bronchoalveolar lavage fluid — P. De Vuyst, P. Dumortier, et al. (1987)

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