Pulmonary intravascular macrophages in horses and ponies.
Abstract: Seven horses (4 anesthetized and 3 awake) and 2 ponies (anesthetized) were studied to evaluate the high sensitivity of the pulmonary circulation of the horse to various blood-borne particles, and to establish the presence of intravascular macrophages in the lung. Pulmonary and systemic pressures and cardiac output before and during particle injection were measured in some animals. An anesthetized foal had a large increase in pulmonary arterial pressure (32 and 34 mm of Hg) within 1 minute of IV administration of small test doses of radioactively labeled liposomes (2.5 mumol/kg of body weight) or a 1% suspension of blue pigment (0.3 ml/kg), respectively. Quantitative real-time gamma camera imaging of the foal revealed high retention of the labeled liposomes during the first pass through the lungs; retention persisted throughout the experiment. Postmortem analysis revealed 55 and 47% lung retention of liposomes and blue pigment, respectively. The 2 anesthetized ponies had increased pulmonary artery pressure of 34 +/- 7 mm of Hg, decreased cardiac output, and 42% lung retention after administration of 1% blue pigment (0.2 ml/kg), whereas 3 awake horses had increased pressure of 28 +/- 9 mm of Hg after 1.8 x 10(8) (1.8-microns-diameter) latex microspheres/kg. None of the injected particles caused vascular obstruction, and they do not cause pulmonary vascular reactivity in species that lack pulmonary intravascular macrophages. Finally, 3 horses (1 anesthetized and 2 awake) were infused IV with small doses of the blue pigment, and their lungs were perfusion-fixed to identify specific labeling of the pulmonary intravascular macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)
Publication Date: 1994-03-01 PubMed ID: 8192263
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
- Research Support
- U.S. Gov't
- P.H.S.
Summary
This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.
The research studied the effect of blood-borne particles on the pulmonary circulation in horses and ponies, finding that certain particles do not cause vascular obstruction and that horses exhibit a high sensitivity to them due to the presence of pulmonary intravascular macrophages.
Research Methodology
- The study involved seven horses, with four of them anesthetized and three awake, and two anesthetized ponies.
- The aim was to evaluate the sensitivity of the their pulmonary circulation to various blood-borne particles and detect the presence of intravascular macrophages in the lungs.
- In some animals, researchers measured pulmonary and systemic pressures and cardiac output before and during the injection of particles.
Experiments and Results
- One anesthetized foal demonstrated a significant increase in pulmonary arterial pressure within a minute of intravenous (IV) administration of small test doses of radioactively labeled liposomes or a suspension of blue pigment.
- Using real-time gamma camera imaging, high retention of the labeled liposomes was observed during their first pass through the foal’s lungs.
- Postmortem analysis showed that a substantial percentage of liposomes and blue pigment were retained in the lungs.
- In anesthetized ponies following administration of blue pigment, there was increased pulmonary artery pressure, decreased cardiac output, and 42% lung retention.
- Three awake horses also exhibited increased pressure after being given latex microspheres.
Conclusions
- None of the injected particles caused vascular obstruction, indicating absence of pulmonary vascular reactivity in species that lack pulmonary intravascular macrophages.
- Post-infusion of blue pigment in three horses, these animals’ lungs were perfusion-fixed to confirm the specific labeling of the pulmonary intravascular macrophages.
In general, this study revealed the role and presence of pulmonary intravascular macrophages in horses and ponies, their reaction to blood-borne particles, and how it affects pulmonary circulation.
Cite This Article
APA
Longworth KE, Jarvis KA, Tyler WS, Steffey EP, Staub NC.
(1994).
Pulmonary intravascular macrophages in horses and ponies.
Am J Vet Res, 55(3), 382-388.
Publication
Researcher Affiliations
- Department of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis 95616.
MeSH Terms
- Aging / physiology
- Anesthesia, General
- Animals
- Blood Pressure
- Cardiac Output
- Drug Carriers
- Electrocardiography
- Horses / physiology
- Indium Radioisotopes
- Lipid Bilayers
- Lung / cytology
- Lung / ultrastructure
- Macrophages / cytology
- Macrophages / physiology
- Macrophages / ultrastructure
- Microscopy, Electron
- Muscle, Smooth, Vascular
- Pulmonary Artery / physiology
- Pulmonary Circulation
- Wakefulness
Grant Funding
- HL25816 / NHLBI NIH HHS
Citations
This article has been cited 2 times.- Aharonson-Raz K, Singh B. Pulmonary intravascular macrophages and endotoxin-induced pulmonary pathophysiology in horses.. Can J Vet Res 2010 Jan;74(1):45-9.
- Atwal OS, Minhas KJ, Williams CS. Ultrastructural response of pulmonary intravascular macrophages to exogenous oestrogen in the bovine lung: translocation of the surface-coat and enhanced cell membrane plasticity and angiogenesis.. J Anat 2001 May;198(Pt 5):611-24.
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