Development and Structure of the Capillary Network

BREATH researchers Giacomo Rößler, Dr. Jonas Labode, PD Dr. Julia Schipke, and Prof. Dr. Christian Mühlfeld from the Institute of Functional and Applied Anatomy at Hannover Medical School (MHH) examined lung tissue samples from five infants (aged 26 days to 18 months) and five adults (aged 20 to 40 years). By combining stereological quantification with 3D segmentation, the team was able to analyze the complex, three-dimensional organization of the capillary network in unprecedented detail.

The results revealed that in early childhood, the ACN is predominantly structured as a double-layered network with numerous interconnections between the layers. In adult lungs, this double-layered architecture was largely reduced and only preserved in small, localized regions. This finding highlights the ongoing remodeling processes during postnatal lung development.

A key observation of the study is that the transition from a double- to a nearly single-layered capillary network does not occur through simple fusion. Rather, the data suggest a selective regression of individual capillary loops. This nuanced restructuring may have important functional implications, particularly regarding potential vascular regeneration niches that persist into adulthood.

Relevance for Research and Clinical Practice

For the first time, this study provides quantitative, three-dimensional reference data on the microvascular organization of the human lung across different developmental stages. This foundational knowledge is essential for understanding developmental disorders such as bronchopulmonary dysplasia and other chronic lung diseases in both children and adults. At the same time, the findings offer new perspectives for regenerative research: the identified remnants of double-layered capillary networks could serve as therapeutically accessible target regions to promote vascular regeneration.

“This work provides the first 3D reference model of human pulmonary capillary architecture from postnatal development to adulthood. Such a foundation is essential to understanding and harnessing vascular repair mechanisms in lung disease,” said BREATH Principal Investigator Prof. Dr. Christian Mühlfeld.

The study compellingly demonstrates how modern imaging and quantitative morphometry can help unravel previously poorly understood aspects of lung development and disease – and pave the way for innovative therapeutic approaches.

The original publication is available here.