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Microvascular effects of a mixed meal tolerance test: a model validation study.
Sebastiaan J W van Kraaij1,2, Boukje Charlotte Eveleens Maarse1,2, Femke P M Hoevenaars3
1Centre for Human Drug Research, Leiden, The Netherlands.
Clinical Physiology and Functional Imaging
|September 23, 2024
Summary
Laser speckle contrast imaging with post-occlusive reactive hyperaemia (PORH) detected microvascular changes after a mixed meal tolerance test (MMTT) in healthy adults. However, these effects were not observed after repeated testing, suggesting a need for method standardization.
Area of Science:
- Cardiovascular Physiology
- Microvascular Function Assessment
- Medical Imaging Techniques
Background:
- Endothelial dysfunction is a precursor to cardiovascular events.
- Assessing optimal endothelial function improvements requires physiological challenges.
- Microvascular responses to metabolic challenges are not well-characterized.
Purpose of the Study:
- To evaluate if imaging techniques can detect microvascular changes induced by a mixed meal tolerance test (MMTT).
- To assess the reliability of different imaging modalities in measuring endothelial function.
- To investigate the impact of MMTT on microvascular reactivity in healthy individuals.
Main Methods:
- Twenty healthy volunteers (age 45-70) underwent two MMTTs (Day 1 and Day 84).
- Imaging included laser speckle contrast imaging (LSCI) with post-occlusive reactive hyperaemia (PORH) and local thermal hyperaemia (LTH), passive leg movement ultrasonography (PLM), and sidestream dark field microscopy (SDFM).
- Measurements were taken at multiple time points pre- and post-MMTT.
Main Results:
- LSCI with PORH showed significant suppression of maximum perfusion and decreased residual perfusion on Day 1 post-MMTT.
- No significant MMTT effects were detected on LSCI LTH, PLM, or SDFM.
- The observed effects of MMTT on LSCI PORH were not significant when the test was repeated on Day 84.
Conclusions:
- SDFM, PLM, and LSCI LTH exhibited high variability, failing to consistently detect MMTT effects.
- LSCI PORH demonstrated the lowest variability and was sensitive to MMTT on Day 1, but not Day 84.
- Further standardization of imaging methods or more potent physiological challenges may be necessary to reliably assess vascular endpoints.
