Confocal Scanning Microscopy in Assessment of Cardiac Allograft Rejection--A Pilot Study
R White1, D J Crossman2, M Isaacson2
1Cardiology, Auckland District Health Board, Auckland City Hospital, Park Road, Grafton, Private Bag 92024, Auckland 1030, New Zealand.
Insights
Confocal microscopy offers high-resolution imaging for cardiac allograft rejection, potentially improving diagnosis by revealing detailed cellular features in biopsies. This advanced technique may enhance the accuracy of grading cardiac rejection.
Area of Science:
- Cardiology
- Pathology
- Microscopy
Background:
- Cardiac allograft rejection diagnosis relies on H&E histology of endomyocardial biopsies.
- Pathologist grading of rejection shows considerable variability.
- Confocal microscopy offers high contrast and resolution imaging for detailed pathological views.
Purpose of the Study:
- To determine if confocal microscopy can detect features of cardiac allograft rejection.
- To explore confocal microscopy's potential in improving rejection assessment.
Main Methods:
- Collected additional samples from 30 heart transplant patient biopsies.
- Imaged samples using confocal microscopy after fluorescent labeling (DAPI, WGA, phalloidin).
- Visualized cell nuclei, cell borders, extracellular matrix, and muscle cell actin.
Main Results:
- Confocal imaging revealed high-resolution features: perivascular/interstitial infiltrate, myocyte damage, and Quilty lesions.
- Detailed views of myocyte damage showed myofilament distortion, aiding distinction between 1R and 2R grades.
- High-contrast fluorescent labeling was achieved, though some variability in DAPI and phalloidin labeling was noted.
Conclusions:
- Confocal microscopy provides high-contrast, high-resolution imaging of cardiac biopsies.
- This technique has the potential to aid in the assessment of cardiac allograft rejection.
- Further exploration of confocal microscopy could improve diagnostic accuracy and reduce inter-pathologist variability.
Abstract:
Cardiac allograft rejection is typically diagnosed on the basis of hematoxylin and eosin (H&E) histology of endomyocardial biopsies. This diagnosis is made based on the degree of immune cell infiltrate and associated myocyte damage. However, considerable variability in rejection grading between pathologists can occur. Confocal microscopy provides high contrast and high resolution imaging that has the potential to provide detailed views of pathological features of allograft rejection. In this pilot study we sought to determine if confocal microscopy could be used to detect features of cardiac rejection. This was achieved by collection of additional sample at 30 biopsy procedures from 15 heart transplant patients. Routine pathological grading of H&E histology identified 5 gradings of 0R, 21 gradings of 1R, and 3 gradings of 2R. From these gradings, 3 samples for 0R, 9 samples for 1R, and 3 samples for 2R were imaged by confocal microscopy. This was achieved by fluorescently labeling sections with DAPI, wheat germ agglutinin, and phalloidin, to visualize the cell nuclei, cell border and extracellular matrix, and muscle cell actin, respectively. Labeling with these fluorescent markers was of high contrast. However, we did note variability in DAPI and phalloidin labeling of tissue sections. Confocal imaging of these labels revealed the following features at high resolution: perivascular and/or interstitial infiltrate, myocyte damage, and Quilty lesions. In particular increased detail of damaged myocytes reveals distortion in myofilament organization that could be exploited to distinguish between 1R and 2R grades. In conclusion, confocal microscopy provided high contrast and resolution imaging of cardiac biopsies that could be explored further to aid assessment of cardiac allograft rejection.
