Methylphenidate and the Vascular Endothelium: Cell Study

"Does methylphenidate harm the heart?" is a question that everyone who takes or is thinking of taking the medication asks at some point. This post does not answer that question, and I want to say so at the start. The study I will summarise does not look at the frequency of heart and vascular diseases. It looks at human vascular cells in the laboratory. There is a big distance between the two, and I tried to write this post keeping that distance honestly.

What I have is the study's abstract. I have not read the full text.

Who the study comes from, and where

The article is titled "Effects of methylphenidate on the human vascular endothelium". Its authors are Wenjie Cai, MaiBritt Giacobini, Cecilia Österholm and Catharina Lavebratt. It was published in the journal Translational Psychiatry in July 2026 (volume 16, issue 1).

This is not a cohort or a clinical trial, it is a laboratory-based study. The main part is cell experiments. Alongside, some markers were also looked at in plasma samples taken from children (87 people) and adults (102 people) with ADHD. In the control groups there are matched 4 children and 44 adults.

This post is a Turkish summary of the article published open access in the journal Translational Psychiatry. The article was published under the Creative Commons Attribution 4.0 (CC BY 4.0) license. The findings belong to the authors of the article, and the account and appraisal here are mine.

Why the study was done

The abstract's introduction goes like this: methylphenidate is a stimulant widely used in the treatment of ADHD. Emerging epidemiological findings suggest that the medication increases the risk of cardiovascular events. However, since causality cannot be inferred, the possible effect of the medication on human vascular endothelial function needs to be investigated separately.

There are two things in this sentence. First, studies that look at records can show an association but cannot say "the medication did it"; those who take the medication and those who do not may have other differences. Second, this is exactly why this study looks at the mechanism: what does the medication do directly to vascular cells? The advantage of a cell study is being able to keep everything under control: the same cell, the same conditions, only the concentration of the medication changes. The disadvantage comes from the same thing, because a real body is not an environment this simplified.

The endothelium is the thin layer of cells lining the inner surface of blood vessels. It plays a role in regulating blood flow, clotting and the passage of substances into tissues. This is general knowledge, not from the study's abstract. On the heart and vessels, I described the effect of the medication on blood pressure and pulse separately in the article on ADHD medication and the heart, blood pressure and pulse.

What was done

The researchers used two types of human cells: endothelial cells from brain microvessels (HBEC) and endothelial cells from the aorta, that is, the main artery (HAEC). They exposed the cells to methylphenidate at different concentrations, among them ones corresponding to the levels seen in the blood during treatment. The exposure lasted 24 and 48 hours.

Then what did they look at? The expression of 29 genes related to endothelial function. Protein levels, with laboratory methods such as ELISA, Western blot, immunofluorescence and FACS. And barrier function, that is, how much the cell layer obstructs the passage of substances: for this FITC-dextran permeability and electrical impedance measurement were used.

Finally, they also measured the main markers that came out different in the cell experiments in the plasma of children and adults with ADHD.

What they found

The findings in the abstract are gathered under four headings.

Genes. Exposure to methylphenidate changed the level of several genes related to endothelial function. The abstract does not give which genes changed in which direction.

In all tested concentrations, including therapeutic levels. Methylphenidate increased the secretion of two proteins: von Willebrand factor (vWF) and tissue plasminogen activator (tPA). These are proteins related to clotting and clot breakdown respectively, secreted by endothelial cells, and their increase is used as a sign of "endothelial activation". This explanation is general knowledge; the abstract only reports the increase.

At concentrations above the therapeutic level. At concentrations of 50 micromolar and/or 100 micromolar (the authors call these "supratherapeutic", that is, above what is seen in ordinary treatment) Claudin-5 expression decreased and the integrity of the endothelial barrier was disrupted. Claudin-5, as general knowledge, is one of the proteins that connect neighbouring cells and ensure the integrity of the barrier.

Blood samples. In children with ADHD, the vWF level in those taking methylphenidate was found higher than in children not taking the medication. This difference was not seen in the adult samples.

The result of the cell experiments by concentration can be summarised at a glance like this:

Concentration	Finding reported by the abstract
All tested concentrations (including therapeutic levels)	Increase in vWF and tPA secretion
50 and/or 100 micromolar (above the therapeutic level)	Decrease in Claudin-5 expression, disruption of endothelial barrier integrity

The authors interpret this as follows: brief exposure to methylphenidate at therapeutic levels is associated with endothelial activation, while concentrations above the therapeutic level may further disrupt barrier integrity. These experimental results may point to possible effects of methylphenidate use on vascular health, and further studies are needed to confirm the findings.

What this finding means for me

First of all let me say this: the "barrier is disrupted at high concentration" part of the finding says nothing directly to people who take the medication, because those concentrations are, by the authors' own definition, above what is seen in treatment. The part that makes me think more is the increase in secretion seen even at therapeutic concentrations, and the vWF difference in children's plasma.

But "endothelial activation" is not a disease, it is a description of a state. The abstract does not say whether this activation is harmful or how long it will last. The cell experiment is 24-48 hours; it does not describe use over many years. So drawing the conclusion "the medication damages the blood vessels" from this finding would be wrong, whereas drawing the conclusion "this subject needs to be researched separately" is right.

If you take the medication, what to do does not change: the heart history before the medication, and monitoring of blood pressure and pulse is a process that goes on with the doctor. Looking at the study and stopping the medication on your own or changing the dose would, I think, be the worst reaction. Stopping the medication suddenly has its own cost.

What it does not say

It does not measure clinical events such as heart attack, stroke or hypertension. The authors mention epidemiological studies in the introduction of the abstract, but the data of this study does not come from them.

A cell experiment is not a body. Cells exposed to a single medication in culture for 24 and 48 hours are not the same as the picture inside the body. Metabolism in the liver, other substances in the blood, use spread over years, all of these are absent from this picture.

The comparison in human samples is small. The child control group is only four people; the abstract does not give the numbers of children taking and not taking the medication separately. The plasma comparison shows an association, it does not establish cause and effect: children taking the medication may have other differences. That no difference was seen in adults is also a separate question: the abstract does not give how the authors explain it.

The abstract also does not separate which result comes from brain vessel cells and which from aortic cells. So I cannot make separate sentences like "it does this to brain vessels" or "it does this to the aorta". The information given is a general picture together for the two cell types.

Finally, the abstract does not say what "high vWF" means for a child. Other studies are needed for that, and the authors also say that additional studies are needed to confirm the findings.

What I take from this

This article can be read in two ways. One is as "is there a new warning about the medication". The other is by seeing how narrow a question the study looked at. I think the right reading is the second.

In my view this study is not an alarm, it is the start of a research question: could there be a biological explanation for an association seen in records? The answer right now is "maybe, it needs confirmation". If you take the medication, there is nothing for you to do because of this study; if there is something you want to ask, take it to the doctor. If your worries about the heart and blood vessels deserve a separate examination, there is no need to put that off either.