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Updated: Aug 27, 2025
Non-invasive Assessment of Microvascular and Endothelial Function
Published on: January 29, 2013
Perfused boundary region as biomarker for endothelial integrity in former preterms in adolescence
Liselotte Van Loo1,2, Karel Allegaert3,4,5, Elena Levtchenko1
1Department of Development and Regeneration, KU Leuven, Leuven, Belgium.
Insights
Extremely low birth weight survivors do not show differences in endothelial glycocalyx thickness (PBR) in adolescence. Further research is needed to understand endothelial integrity markers in this population.
Area of Science:
- Vascular biology and pediatric health
- Endothelial function assessment
- Microvascular research
Background:
- Extremely low birth weight (ELBW) survivors exhibit microvascular differences in kidney and retina, indicating potential endothelial integrity issues.
- The endothelial glycocalyx, a key component of vascular integrity, can be assessed by measuring the perfused boundary region (PBR).
- Understanding endothelial integrity in ELBW survivors is crucial for long-term health outcomes.
Purpose of the Study:
- To establish reference values for PBR in healthy adolescents.
- To compare PBR and other microvascular markers between healthy controls and ELBW survivors.
- To explore potential perinatal determinants and correlations among microvascular markers in ELBW survivors.
Main Methods:
- Utilized the PREMATCH cohort, including 87 healthy controls and 93 ELBW survivors.
- Assessed endothelial integrity via perfused boundary region (PBR) using sidestream dark-field imaging.
- Measured microvascular markers including blood pressure, estimated glomerular filtration rate (eGFRcysC), and retinal imaging in early adolescence.
Main Results:
- Established reference values for PBR in healthy adolescents (average 1.90 µm, SD 0.30).
- Found no significant difference in PBR between ELBW survivors and healthy controls in early adolescence.
- ELBW survivors presented with higher blood pressure, lower eGFRcysC, and altered retinal vessel characteristics compared to controls.
Conclusions:
- Reference values for adolescent PBR were successfully generated.
- Despite correlations between some microvascular parameters, PBR did not emerge as a definitive marker for endothelial integrity in ELBW survivors due to confounding factors.
- Further investigation is required to fully elucidate endothelial integrity and its determinants in ELBW survivors.
Introduction:
Extremely low birth weight (ELBW) survivors have microvascular structural differences already described in kidney and retina, suggesting changes in endothelial integrity. A biomarker of endothelial integrity is perfused boundary region (PBR), which measures glycocalycal thickness. The endothelial glycocalyx is a complex, highly versatile structure with essential roles in vascular integrity and function. We explored PBR patterns together with other microvascular markers in healthy controls and former ELBW children.
Methods:
In the PREMATCH cohort (87 healthy controls, 93 ELBW survivors), we assessed endothelial integrity by calculating PBR (sidestream dark-field imaging), several microvascular markers (blood pressure, estimated glomerular filtration rate (eGFRcysC)), and retinal imaging in early adolescence. We explored differences between both groups, and searched for perinatal determinants of PBR and correlations between different microvascular markers.
Results:
We provided reference values for PBR (average 1.90 µm, SD 0.30) in children. PBR was not different from ELBW survivors during early adolescence, despite their higher blood pressure, lower eGFRcysC, and different retinal vessel width and tortuosity.
Conclusions:
We generated reference values for PBR in early adolescence. Despite some correlations between microvascular parameters, there seem to be numerous confounders to propose PBR as a marker for endothelial integrity in ELBW survivors.
Impact:
The endothelial glycocalyx is a complex and versatile structure. Changes in blood pressure and retinal and renal vascularization suggest a disturbance of its integrity in extremely low birth weight (ELBW) survivors. Its thickness can be measured by calculating perfused boundary region (PBR) using sidestream dark-field imaging, with a higher PBR indicating a thinner glycocalyx. We generated reference values for PBR in healthy adolescents. These values were not different in former ELBW children. Despite some correlations of PBR with other microvascular biomarkers, these are not strong enough to describe endothelial integrity and its covariates in former ELBW children.
