Evidence map›Paper›PMID 41731530›Full record

ArticleFluids and barriers of the CNS2026

Evaluating sex as a biological variable in in vitro blood-brain barrier models: insights from primary mouse brain endothelial cells.

Maria Thaysen, Line Toft Ørum, Alberte Bay Villekjaer Pedersen, Nana Svane, Signe Emilie Dannulat Frazier, Lasse Saaby, Birger Brodin, Mie Kristensen

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. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing 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

0 citing papers in PubMed.

No citing paper in PubMed yet.

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

8 authors.

Maria ThaysenDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark. mthaysen@sund.ku.dk.
Line Toft ØrumDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Alberte Bay Villekjaer PedersenDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Nana SvaneDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Signe Emilie Dannulat FrazierDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Lasse SaabyDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Birger BrodinDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark.
Mie KristensenDepartment of Pharmacy, University of Copenhagen, Copenhagen, Denmark. mie.kristensen@sund.ku.dk.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionPreclinical neurological research relies predominantly on male animals, despite well-documented sex differences in neurological diseases, which ultimately may result in sex-dependent treatment efficiency. A key player in neurological disease treatment is the blood-brain barrier (BBB), the barrier property of brain capillaries, which tightly regulates molecular exchange between the blood and the brain. The BBB represents a major obstacle to brain drug delivery due to its tightness and presence of drug efflux pumps, with some studies suggesting that the BBB properties may differ between sexes. However, in vivo evidence is limited, and whether primary in vitro BBB models, commonly used to evaluate the permeability of novel drug candidates, display sex-dependent differences, lacks attention. With this study, we therefore aimed to investigate if a mouse in vitro model of the BBB displayed sex-dependent differences in BBB morphology and phenotype, and therefore whether sex should be considered a critical variable in its use.

methodsPrimary mouse brain endothelial cells (PMBEC) were isolated from cortices of sexually mature C57Bl/6 mice. Transendothelial electrical resistance (TEER) measurements and transport of the paracellular marker [14C]-mannitol were used to evaluate monolayer tightness. Gene and protein expression of tight junction proteins, selected transporters and receptors as well as efflux transporters were assessed. P-glycoprotein (P-gp) function was evaluated in bidirectional [3H]-digoxin transport studies.

resultsFemale- and male-derived PMBECs grew in monolayers, expressed the endothelial marker von Willebrand factor and showed elongated spindle-shaped morphology typical of endothelial cells. Female- and male derived PMBEC monolayers exhibited comparable barrier properties as reflected by TEER measurements and mannitol permeability. Tight junction mRNA and protein expression did not differ between sexes and displayed similar expression levels of key transporters. Lastly, P-gp and breast cancer resistance protein were detected in PMBECs of both female and male origin and P-gp function was similar in the two sexes.

conclusionOur present study shows that PMBECs do not differ substantially between sexes. However, as this is the first study of its kind, it warrants further investigations into sex differences in PMBECs and whether these fully translates to the in vivo BBB.

Indexed as

Blood-Brain BarrierEndothelial CellsSex CharacteristicsAnimalsBrainCells, CulturedFemaleMaleMiceMice, Inbred C57BLBlood-brain barrierIn vitro modelsPrimary mouse brain endothelial cellsSex difference

Identifiers

PMID41731530
PMCPMC13032606

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

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.