電子たばこ香料バニリンがヒト胚性幹細胞発生を阻害(Vanillin Flavoring in E-Cigarettes Disrupts Human Embryonic Stem Cell Development)

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2026-08-12 カリフォルニア大学リバーサイド校(UCR)

米カリフォルニア大学リバーサイド校(UCR)の研究チームは、電子たばこに広く使用される香料成分バニリン(vanillin)が、ヒト胚性幹細胞の正常な発生過程を阻害する可能性を明らかにした。研究では、妊娠約3週相当のヒト胚を模した胚性幹細胞を用いて実験を行った。その結果、高濃度のバニリンは細胞死を引き起こし、より低濃度でも多能性(さまざまな細胞へ分化できる能力)を失わせることが判明した。また、本来は内胚葉・中胚葉・外胚葉の3系統へ分化すべき細胞が、内胚葉へ偏って分化することも確認された。作用機序として、バニリンが細胞表面のTRPV4チャネルに結合し、カルシウム流入を介して分化制御を乱すことが示された。これにより神経系や筋肉などを形成する外胚葉・中胚葉の発達が妨げられる可能性がある。研究は実験室レベルの結果であり、人体への影響を直接証明するものではないが、妊娠中や妊娠を希望する女性の電子たばこ使用に注意を促す重要な知見となる。

<関連情報>

電子タバコの香料であるナノモル濃度のバニリンは、TRPV4の活性化を介してヒト胚性幹細胞の多能性を阻害し、内胚葉分化を促進するようである Nanomolar vanillin, an e-cigarette flavorant, appears to disrupt pluripotency and promote endodermal differentiation in human embryonic stem cells via TRPV4 activation

Shabnam Etemadi,Prue Talbot
Human Reproduction  Published:12 August 2026
DOI:https://doi.org/10.1093/humrep/deag126

Schematic showing a pregnant person exposed to vanillin aerosol from e-cigarette vaping, leading to maternal exposure and transfer to an hESC colony model representing epiblast at week 2–3, which expresses TRPV4. Functional activation of TRPV4 is measured by intracellular calcium influx using Fluo-8 dye, with a TRPV4 antagonist and function-blocking antibody blocking all effects. At nanomolar concentrations, outcomes include changes in the undifferentiated and pluripotency state (EpCAM, OCT4) and potential lineage specification (PAX6, NCAM, SOX17). At micromolar concentrations, outcomes assessed by time-lapse imaging include colony expansion and morphology (detachment, elongation), mitochondrial dysfunction (MTT reductase activity), and developmental toxicity (cleaved caspase-3, brightness/area ratio). A separate diagram poses the question 'From Vape to Embryo: What Concentrations Are Encountered During Development?' showing factors linking vanillin in e-cigarette liquids to fetal blood concentration: puff number, % transfer efficiency, % retention, blood volume, and % transfer to blood.

Abstract

STUDY QUESTION
Does vanillin, at concentrations relevant to maternal exposures during vaping, disrupt gastrulation-related processes in human embryonic stem cells (hESCs) by activating TRPV4 channels?

SUMMARY ANSWER
Activation of TRPV4 channels by nanomolar concentrations of vanillin promoted an exit from pluripotency and a shift toward endodermal gene expression, while micromolar concentrations induced developmental toxicity, identifying a concentration-dependent mechanism by which vanillin, a flavoring agent in electronic cigarette (EC) aerosols, may pose risks to embryonic development during pregnancy.

WHAT IS KNOWN ALREADY
The use of ECs during pregnancy is increasing, potentially driven by perceptions of reduced harm and the appeal of flavoring agents, such as vanillin. However, vanillin activates transient receptor potential (TRP) channels, raising concerns about its impact on early embryonic development.

STUDY DESIGN, SIZE, DURATION
hESCs, which model the epiblast stage of development, were treated in vitro for various times with vanillin, a TRPV4 antagonist, a TRPV4 function-blocking antibody, or vanillin combined with either the antagonist or antibody. All experiments were done three times with different passages of stem cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS
After variable periods of exposure, the hESC colonies were evaluated for activation of TRPV4 channels and calcium influx, colony growth, colony detachment, increased cell death, mitochondrial dysfunction, colony morphology, gap formation, downregulation of EpCAM, loss of pluripotency, and initiation of differentiation.

MAIN RESULTS AND THE ROLE OF CHANCE
We demonstrate that vanillin, at concentrations relevant to maternal EC exposure, significantly (P < 0.05) disrupted gastrulation-related processes in hESCs. hESCs, which model the epiblast during Weeks 2–3 of human development, exhibited TRPV4 channel expression and showed a significant increase in intracellular calcium upon nanomolar-to-micromolar vanillin exposure, as detected by the Fluo-8 calcium dye. Time-lapse imaging and quantitative analysis indicated that micromolar vanillin impaired colony expansion, induced colony detachment, and increased cell death over 72 h, while concurrently reducing mitochondrial reductase activity in the MTT assay. At nanomolar concentrations, vanillin promoted TRPV4 activation, an exit from pluripotency, downregulation of EpCAM cell adhesion protein, intercellular gap formation, and a shift toward endodermal gene expression. All effects were blocked by a TRPV4 antagonist (HC067047), identifying activation of this channel as a critical mediator of vanillin-induced toxicity.

LARGE SCALE DATA
N/A.

LIMITATIONS, REASONS FOR CAUTION
Our data are derived from in vitro experiments, as direct investigation of early human development is ethically and practically limited. Although our findings do not establish embryo lethality or malformation in vivo, the observed loss of pluripotency and SOX17 upregulation, consistent with endodermal induction, at nanomolar concentrations of vanillin are signs of early cellular perturbations that could compromise human development.

WIDER IMPLICATIONS OF THE FINDINGS
Nanomolar vanillin concentrations, which our exposure model estimates reach the embryo during early pregnancy in EC users, were sufficient to activate TRPV4 channels in hESCs and alter germ layer specification. Micromolar concentrations produced cytotoxic effects and increased cell death. These findings indicate that vanillin exposure at levels attainable during EC use disrupts intracellular Ca2+ homeostasis and compromises core processes of early human development. Maternal EC use during pregnancy therefore represents a significant and previously under-appreciated risk to early embryogenesis. Clinicians should counsel patients who are pregnant or planning pregnancy about this potential harm, and regulatory agencies should consider mandatory ingredient disclosure on EC packaging.

FUNDING
This research was supported by grant number T32IR4848 from the Tobacco-Related Disease Research Program (TRDRP), by grant number EDUC4-12752 from the California Institute of Regenerative Medicine (CIRM), and by UCR Yvonne Danielson Endowed Graduate and Dissertation Completion Fellowship Awards. The content is solely the responsibility of the authors and does not necessarily represent the official view of the TRDRP, CIRM, or UCR.

DISCLOSURES
The authors have no conflicts of interest to declare.

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