Evidence map›Paper›PMID 41691326›Full record

ArticleFluids and barriers of the CNS2026

Perivascular spaces balance vascular dimensions without impairing brain clearance mechanisms.

Nina G Smets, Bente van der Velden, Jenneke Oudijn, Lindy K Alles, Gustav J Strijkers, Erik N T P Bakker

Abstract read
In one paragraph

Article in Fluids and barriers of the CNS, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.

0numbers the graph read from it
0cells of the map it votes in
1citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

1 citing paper in PubMed.

  1. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Nina G SmetsBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.ORCID http://orcid.org/0000-0001-8846-9070
Bente van der VeldenBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.
Jenneke OudijnBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.
Lindy K AllesBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.
Gustav J StrijkersBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands.ORCID http://orcid.org/0000-0001-6700-5058
Erik N T P BakkerBiomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Meibergdreef 9, Amsterdam, The Netherlands. n.t.bakker@amsterdamumc.nl.ORCID http://orcid.org/0000-0003-2819-5818

Funding

Nederlandse Organisatie voor Wetenschappelijk Onderzoek project OCENW.M20.238
6 · The paper itself

Abstract

backgroundPerivascular spaces (PVS) contribute to brain clearance, as they connect the cerebrospinal fluid (CSF) in the subarachnoid space and ventricular system with the interstitial fluid. We tested the hypothesis that the size and exchange function of PVS depend on the degree of blood vessel dilatation.

methodsTo induce vasodilatation, we subjected mice to hypercapnia and compared this to normocapnic conditions. The study comprised three experimental approaches. In the first series, cranial window surgery and two-photon microscopy were used to assess CO₂-induced changes in vascular and PVS morphology. The second series investigated tracer influx following cisterna magna tracer injection and 30-min exposure to either normocapnia or hypercapnia, with subsequent confocal imaging of brain slices. The third approach evaluated tracer efflux and parenchymal diffusion after intracortical injection via a cranial window port and widefield fluorescence imaging.

resultsArterial blood sampling confirmed hypercapnia. Hypercapnia led to vasodilatation in cerebral arteries, but not cerebral veins. The periarterial spaces balanced vasodilatation by a decrease in size. No effect was found on perivenous spaces. Despite changes in size of the PVS, no significant differences were found in CSF tracer influx from the subarachnoid space into the brain parenchyma, or subregions of the brain. Additionally, hypercapnia did not affect the efflux of fluorescent tracer from the cortex over the course of one hour. DISCUSSION: Hypercapnia-induced vasodilatation was accommodated by shrinkage of the periarterial spaces. Veins and perivenous spaces were not affected. We propose that PVS might act primarily as a buffer for volume changes induced by vasomotor activity. Changes in PVS dimensions, induced by relatively mild vasomotor changes had no effect on brain clearance related parameters under the current experimental conditions.

Indexed as

BrainCerebral ArteriesGlymphatic SystemVasodilationAnimalsCarbon DioxideFemaleHypercapniaMaleMiceMice, Inbred C57BLCarbon DioxideBrain clearanceCerebrospinal fluidHypercapniaMicroscopyPerivascular spacesVasodilatation

Identifiers

PMID41691326
PMCPMC12927245

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.