Focal ischemic stroke leads to lung injury and reduces alveolar macrophage phagocytic capability in rats 11 Medical and Health Sciences 1102 Cardiorespiratory Medicine and Haematology

Cynthia S. Samary, Alane B. Ramos, Lígia A. Maia, Nazareth N. Rocha, Cíntia L. Santos, Raquel F. Magalhães, Amanda L. Clevelario, Pedro M. Pimentel-Coelho, Rosália Mendez-Otero, Fernanda F. Cruz, Vera L. Capelozzi, Tatiana P.T. Ferreira, Thea Koch, Marcelo Gama De Abreu, Claudia C. Dos Santos, Paolo Pelosi, Pedro L. Silva, Patricia R.M. Rocco

Research output: Contribution to journalArticlepeer-review


Background: Ischemic stroke causes brain inflammation, which we postulate may result in lung damage. Several studies have focused on stroke-induced immunosuppression and lung infection; however, the possibility that strokes may trigger lung inflammation has been overlooked. We hypothesized that even focal ischemic stroke might induce acute systemic and pulmonary inflammation, thus altering respiratory parameters, lung tissue integrity, and alveolar macrophage behavior. Methods: Forty-eight Wistar rats were randomly assigned to ischemic stroke (Stroke) or sham surgery (Sham). Lung function, histology, and inflammation in the lung, brain, bronchoalveolar lavage fluid (BALF), and circulating plasma were evaluated at 24 h. In vitro, alveolar macrophages from naïve rats (unstimulated) were exposed to serum or BALF from Sham or Stroke animals to elucidate possible mechanisms underlying alterations in alveolar macrophage phagocytic capability. Alveolar macrophages and epithelial and endothelial cells of Sham and Stroke animals were also isolated for evaluation of mRNA expression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. Results: Twenty-four hours following ischemic stroke, the tidal volume, expiratory time, and mean inspiratory flow were increased. Compared to Sham animals, the respiratory rate and duty cycle during spontaneous breathing were reduced, but this did not affect lung mechanics during mechanical ventilation. Lungs from Stroke animals showed clear evidence of increased diffuse alveolar damage, pulmonary edema, and inflammation markers. This was associated with an increase in ultrastructural damage, as evidenced by injury to type 2 pneumocytes and endothelial cells, cellular infiltration, and enlarged basement membrane thickness. Protein levels of proinflammatory mediators were documented in the lung, brain, and plasma (TNF-α and IL-6) and in BALF (TNF-α). The phagocytic ability of macrophages was significantly reduced. Unstimulated macrophages isolated from naïve rats only upregulated expression of TNF-α and IL-6 following exposure to serum from Stroke rats. Exposure to BALF from Stroke or Sham animals did not change alveolar macrophage behavior, or gene expression of TNF-α and IL-6. IL-6 expression was increased in macrophages and endothelial cells from Stroke animals. Conclusions: In rats, focal ischemic stroke is associated with brain-lung crosstalk, leading to increased pulmonary damage and inflammation, as well as reduced alveolar macrophage phagocytic capability, which seems to be promoted by systemic inflammation.

Original languageEnglish
Article number249
JournalCritical Care
Issue number1
Publication statusPublished - Oct 5 2018


  • Brain-lung interaction
  • Focal ischemic stroke
  • Inflammation
  • Lung injury
  • Macrophages

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine


Dive into the research topics of 'Focal ischemic stroke leads to lung injury and reduces alveolar macrophage phagocytic capability in rats 11 Medical and Health Sciences 1102 Cardiorespiratory Medicine and Haematology'. Together they form a unique fingerprint.

Cite this