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Intravascular macrophages in pulmonary capillaries of humans
1Department of Anesthesiology, University of Texas Medical Branch, Galveston 77550.
Abstract:
Pulmonary intravascular macrophages reside in the pulmonary capillaries and phagocytize bacteria and particulates. These cells are prominent in several animals species, but they have not been described in humans. Samples of lung tissue from patients undergoing thoracotomies for excision of noninfectious diseases were examined with transmission electron microscopy to determine if pulmonary intravascular macrophages are present in humans. The macrophages, with cytoplasm closely adjacent to the capillary and with an irregular contour, were seen in specimens from all patients. The morphologic features of human pulmonary intravascular macrophages resemble the appearance of these cells in animals. The potential significance of pulmonary intravascular macrophages is discussed with regard to sepsis-induced acute respiratory failure.
Insights
Pulmonary intravascular macrophages, previously unseen in humans, were identified in human lung capillaries. These cells resemble those in animals and may play a role in acute respiratory failure.
Area of Science:
- Pulmonary immunology
- Cell biology
- Respiratory medicine
Background:
- Pulmonary intravascular macrophages (PIMs) are known to reside in pulmonary capillaries in various animal species.
- These cells are involved in phagocytizing bacteria and particulates within the lung vasculature.
- PIMs have not been previously described or characterized in human lung tissue.
Purpose of the Study:
- To determine the presence and morphology of pulmonary intravascular macrophages in humans.
- To compare human PIMs with those observed in animal models.
- To explore the potential role of human PIMs in sepsis-induced acute respiratory failure.
Main Methods:
- Examination of human lung tissue samples obtained during thoracotomies for noninfectious diseases.
- Utilized transmission electron microscopy (TEM) for high-resolution imaging of cellular structures.
- Morphological analysis of macrophages situated within pulmonary capillaries.
Main Results:
- Pulmonary intravascular macrophages were identified in lung tissue specimens from all human patients studied.
- The observed human PIMs exhibited close cytoplasmic proximity to the capillary endothelium and irregular contours.
- The morphology of human PIMs was found to be similar to that of PIMs in other animal species.
Conclusions:
- Pulmonary intravascular macrophages are present in humans, residing within pulmonary capillaries.
- Human PIMs share morphological similarities with their counterparts in animals.
- The presence and characteristics of human PIMs suggest a potential role in the pathophysiology of sepsis-induced acute respiratory failure.