The original article, published in January 2019 in the same journal under the title Effects of Mandibular Extension on Pial Arteriolar Diameter Changes in Glucocorticoid-Induced Hypertensive Rats, was authored by a team of Italian researchers including Lapi, Varanini, Galasso, Di Maro, Federighi, Del Seppia, Colantuoni and Scuri. The work appeared in the journal’s Vascular Physiology section and carried the article number 10:3, reflecting its position as the third paper published in that volume of the journal. The study’s stated aim was to examine how mechanical manipulation of the jaw might affect cerebral microvascular tone in an animal model of hypertension induced by glucocorticoids, a class of steroid hormones that includes cortisol and its synthetic analogues.

According to the retraction notice, the trouble began after publication, when concerns were raised regarding the integrity of the images in the published figures. In experimental physiology, figures often contain photomicrographs, fluorescence images, or other visual records of biological preparations, and these images serve as primary evidence for the paper’s claims. When questions arise about whether images have been duplicated, manipulated, or otherwise altered, the evidentiary foundation of the entire study comes into question. That is precisely the situation the journal confronted here.

Frontiers, the publisher, launched an investigation conducted in accordance with its own research integrity policies. The outcome, as stated in the notice, was stark: the authors failed to provide a satisfactory explanation during the investigation. In the absence of a credible account of how the problematic images came to be, the publisher concluded that the data and conclusions of the article had been deemed unreliable. On that basis, the retraction was issued, formally severing the paper from the scientific record.

The retraction followed the procedural safeguards that have become standard in scholarly publishing. It was approved by the Chief Editors of Frontiers in Physiology together with the Chief Executive Editor at Frontiers, ensuring that the decision was made at the highest editorial level rather than by a single handling editor. The authors were informed of the retraction and given an opportunity to respond, and that communication has been recorded by the publisher. This documentation matters, because it creates a permanent record of whether the authors contested the decision, cooperated with the investigation, or declined to engage, information that is often of keen interest to the research integrity community.

The timeline of the retraction itself was brisk. The retraction notice was received by the journal on 12 October 2026, accepted on 13 October 2026, and published on 19 October 2026. The notice was approved by Dirk M. Hermann of the University of Duisburg-Essen in Germany, acting in his editorial capacity. The speed of the process, once the investigation had concluded, reflects a growing emphasis among publishers on acting quickly once integrity concerns are substantiated, rather than allowing disputed papers to linger in the literature for years while cases are adjudicated.

For readers unfamiliar with the underlying science, the original study sat at the intersection of several physiological domains. Pial arterioles are the small vessels that run across the surface of the brain beneath the arachnoid membrane, and they play a crucial role in regulating cerebral blood flow. Their diameter can change in response to a wide range of stimuli, including blood pressure, metabolic signals, and neural activity, a property known as vascular reactivity. Hypertension, particularly the form induced experimentally by chronic glucocorticoid administration, is known to alter vascular reactivity and to damage the microvasculature over time, making the glucocorticoid-treated rat a common model for studying how high blood pressure reshapes the cerebral circulation.

The mandibular component of the study was the element that gave the paper its distinctive character. The temporomandibular joint and the muscles of mastication are richly innervated, and altered jaw position has been reported in some lines of research to influence cardiovascular and cerebrovascular parameters, a topic of ongoing interest in fields ranging from dentistry to autonomic physiology. The idea that extending the lower jaw might produce measurable changes in pial arteriolar diameter, and that such changes might differ in hypertensive versus normodynamic animals, represented an attempt to connect orofacial mechanics with cerebral microvascular control. Whether such a connection exists, and by what mechanism, remains a question that the retracted paper can no longer be cited to answer.

The retraction carries practical consequences for the research community. Under the norms of scholarly publishing, a retracted article should not be cited as supporting evidence, and databases such as the paper’s DOI record now flag the article as retracted, directing readers to the retraction notice. The original article remains accessible online, as is standard practice, but it is permanently watermarked by the retraction so that anyone who encounters it will know its status. This approach preserves the transparency of the scientific record while preventing the paper’s findings from quietly circulating as though nothing had happened. Researchers who had drawn on the 2019 study in reviews, meta-analyses, or grant applications will need to revisit those works and remove or contextualize the citation.

The case is also a reminder of how central image integrity has become to the policing of the scientific literature. Modern forensic analysis can detect duplicated regions within a single figure, reuse of the same image across different experiments, and subtle digital manipulations that would have escaped notice in the era of printed journals. Journals including Frontiers have invested in screening tools and editorial workflows designed to catch such problems, but many cases still surface only after publication, when readers or automated checks flag suspicious figures. The present retraction, initiated on the basis of concerns about published figures and closed after the authors could not satisfactorily explain them, follows that now-familiar arc. For the vascular physiology community, the message is that the question of whether mandibular extension influences pial arteriolar diameter in hypertensive rats remains open, and any future answer will have to rest on data that survive scrutiny.

Subject of Research: Retraction of a 2019 Frontiers in Physiology study on mandibular extension and pial arteriolar diameter in glucocorticoid-induced hypertensive rats due to image integrity concerns

Article Title: Retraction: Effects of mandibular extension on pial arteriolar diameter changes in glucocorticoid-induced hypertensive rats

Article References: Frontiers Editorial Office (2026). Retraction: Effects of mandibular extension on pial arteriolar diameter changes in glucocorticoid-induced hypertensive rats. Frontiers in Physiology, 17, Article 2026350. https://doi.org/10.3389/fphys.2026.2026350

Image Credits: AI Generated

DOI: 10.3389/fphys.2026.2026350

Keywords: retraction, Frontiers in Physiology, pial arterioles, cerebral blood flow, hypertension, glucocorticoids, mandibular extension, vascular physiology, research integrity, image manipulation, rat model, microcirculation