Direct vascular contact is a hallmark of cerebral astrocytes

• Published in: Cell reports (Cambridge) 2022-04, Vol.39 (1), p.110599-110599, Article 110599
• Main Authors: Hösli, Ladina, Zuend, Marc, Bredell, Gustav, Zanker, Henri S., Porto de Oliveira, Carlos Eduardo, Saab, Aiman S., Weber, Bruno
• Format: Article
• Language: English
• Subjects: astrocyte; astrocyte network; astrocyte-vessel contact; Astrocytes - metabolism; Brain - metabolism; cortex; CP: Neuroscience; Gap Junctions - metabolism; Hippocampus; in vivo; metabolism; two-photon imaging; vasculature; vessel
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2022.110599

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. [Display omitted] •Of all gray matter astrocytes, 99.8% are connected to at least one blood vessel•Most protoplasmic astrocytes maintain direct contact to three blood vessels•Not astrocyte size, but vessel density, defines the number of contacted vessels•Astrocytes without a direct vascular contact were found only in the hippocampus Using in vivo and ex vivo imaging, Hösli et al. find that all gray matter astrocytes in the investigated brain regions are connected to at least one vessel. Only in the hippocampus, which showed the lowest vessel density, did they discover single astrocytes without a direct vascular contact.