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Potential use of indium-111-labeled polymorphonuclear leukocytes for the detection of lung microvascular injury
D K Das1, H Steinberg, D Bandyopadhyay
1Cardiovascular Laboratories, University of Connecticut School of Medicine, Farmington 06032.
Abstract:
The early stages of microvascular injury are often difficult to detect due to the lack of a suitable marker to assess such an injury. We utilized the well known phenomenon of polymorphonuclear leukocyte (PMN) migration to the microvascular bed as a result of acute inflammatory reactions originating from the damaged cells. A radiotracer technique was developed, employing indium-111-labeled PMN for the detection of microvascular injury induced by hyperoxia. New Zealand white rabbits exposed to either 100% oxygen or air for various intervals of time were injected with indium-111-tropolone or oxine-labeled PMNs. Influx of radioactive PMN into the lung was detected in 72 hr/oxygen-exposed animals using gamma scintigraphic technique. Analysis of dry/wet ratios and histological examinations of the lung biopsies indicated noncardiogenic edema formation at this stage. Mortality was 50% beyond 96 hr/oxygen exposure. Our study thus provided a means to detect early microvascular injury during 72 hr/oxygen-exposure, which was not detectable by any other noninvasive techniques. The use of indium-111-labeled PMN thus appears to be a potentially important tool for the clinical assessment of lung microvascular injury.
Insights
This study developed a novel radiotracer technique using indium-111-labeled polymorphonuclear leukocytes (PMNs) to detect early microvascular lung injury from hyperoxia. This method offers a noninvasive tool for assessing lung damage not previously detectable.
Area of Science:
- Biomedical Engineering
- Radiology
- Pulmonary Medicine
Background:
- Early microvascular injury detection is challenging due to the lack of specific biomarkers.
- Polymorphonuclear leukocyte (PMN) migration is a known indicator of acute inflammatory responses in damaged tissues.
Purpose of the Study:
- To develop and validate a radiotracer technique for detecting early microvascular injury induced by hyperoxia.
- To assess the utility of indium-111-labeled PMNs in identifying lung microvascular damage.
Main Methods:
- Developed a radiotracer technique using indium-111-labeled PMNs.
- Exposed New Zealand white rabbits to 100% oxygen or air for varying durations.
- Administered indium-111-labeled PMNs and utilized gamma scintigraphy to detect lung influx.
- Performed lung biopsy analysis (dry/wet ratios, histology).
Main Results:
- Detected influx of radioactive PMNs in lungs of rabbits exposed to oxygen for 72 hours.
- Identified noncardiogenic edema formation at this early stage.
- Observed 50% mortality in animals exposed to oxygen beyond 96 hours.
Conclusions:
- Indium-111-labeled PMN scintigraphy can detect early microvascular lung injury from hyperoxia, previously undetectable by noninvasive methods.
- This technique shows potential as a clinical tool for assessing lung microvascular injury.