Direct vascular contact is a hallmark of cerebral astrocytes
Ladina Hösli,
Marc Zuend,
Gustav Bredell,
Henri S. Zanker,
Carlos Eduardo Porto de Oliveira,
Aiman S. Saab,
Bruno Weber
Affiliations
Ladina Hösli
University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
Marc Zuend
University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
Gustav Bredell
ETH Zurich, Computer Vision Laboratory, Department of Information Technology and Electrical Engineering, 8092 Zurich, Switzerland
Henri S. Zanker
University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
Carlos Eduardo Porto de Oliveira
ETH Zurich, Computer Vision Laboratory, Department of Information Technology and Electrical Engineering, 8092 Zurich, Switzerland
Aiman S. Saab
University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland
Bruno Weber
University of Zurich, Institute of Pharmacology and Toxicology, 8057 Zurich, Switzerland; Neuroscience Center Zurich, University and ETH Zurich, 8057 Zurich, Switzerland; Corresponding author
Summary: Astrocytes establish extensive networks via gap junctions that allow each astrocyte to connect indirectly to the vasculature. However, the proportion of astrocytes directly associated with blood vessels is unknown. Here, we quantify structural contacts of cortical astrocytes with the vasculature in vivo. We show that all cortical astrocytes are connected to at least one blood vessel. Moreover, astrocytes contact more vessels in deeper cortical layers where vessel density is known to be higher. Further examination of different brain regions reveals that only the hippocampus, which has the lowest vessel density of all investigated brain regions, harbors single astrocytes with no apparent vascular connection. In summary, we show that almost all gray matter astrocytes have direct contact to the vasculature. In addition to the glial network, a direct vascular access may represent a complementary pathway for metabolite uptake and distribution.
