Semaglutide improves blood vessel function in Japanese T2DM patients independently of weight, glucose, or cholesterol changes | Research

The takeaway

In 24 Japanese T2DM patients, once-weekly semaglutide significantly improved vascular endothelial function (RHI 1.62→2.04, p<0.01) independently of concurrent improvements in weight, HbA1c, and LDL cholesterol.

Direct vascular protection
Semaglutide improved endothelial function independently of metabolic improvements—suggesting a direct GLP-1-mediated vascular protective effect beyond glucose and weight control

What the researchers found

RHI: 1.62±0.19 → 2.04±0.60 (p<0.01). BW, HbA1c, LDL-cho also improved (all p<0.01). hsCRP trended down (NS). No correlation between metabolic changes and RHI improvement. 24 patients, mean age 55, 83% male.

Why it matters

Endothelial dysfunction is the earliest step in atherosclerosis. Demonstrating that semaglutide directly improves endothelial function—independent of metabolic improvements—reveals a direct vascular protective mechanism.

How the study worked

Retrospective observational study at Jinnouchi Hospital (Japan). 24 T2DM patients initiated on once-weekly SC semaglutide since 2021. RHI by EndoPAT. Clinical parameters before and after treatment.

What this study cannot tell us

Small sample (24). Retrospective. No control group. Japanese population. RHI has measurement variability. Follow-up duration not specified.

How to read the evidence

Small retrospective observational study. Novel finding but needs larger confirmation.

When this study was published

Published in 2025.

The bigger picture

This adds direct endothelial protection to semaglutide's cardiovascular benefit portfolio. The lack of correlation with metabolic changes suggests a novel, independent vascular mechanism.

Questions still open

What direct mechanism improves endothelial function independently of metabolic effects?
Would this translate to reduced atherosclerosis progression on imaging?
Do other GLP-1 drugs show the same direct vascular effect?

Common questions

Does semaglutide protect blood vessels?

Yes. This study measured blood vessel health directly using a reactive hyperemia test and found semaglutide significantly improved vascular function. Importantly, this improvement was independent of weight loss, blood sugar, or cholesterol changes—suggesting a direct protective effect on blood vessel walls.

What is endothelial function and why does it matter?

The endothelium is the inner lining of blood vessels. When it functions well, blood flows smoothly and vessel walls resist plaque buildup. When damaged (endothelial dysfunction), atherosclerosis begins. Semaglutide's ability to improve endothelial function may explain part of its cardiovascular protective effects.

Read the original research

Once-Weekly Semaglutide Is Associated With Improvement in Vascular Endothelial Function in Patients With Type 2 Diabetes Mellitus: A Retrospective Observational Study.

Cureus, 17(12), e99998

View on PubMed ↗Publisher’s paper ↗

Citation

Sugiyama, Seigo; Yoshida, Akira; Kurinami, Noboru; Hieshima, Kunio; Jinnouchi, Katsunori; Suzuki, Tomoko; Miyamoto, Fumio; Kajiwara, Keizo; Jinnouchi, Hideaki. (2025). Once-Weekly Semaglutide Is Associated With Improvement in Vascular Endothelial Function in Patients With Type 2 Diabetes Mellitus: A Retrospective Observational Study.. Cureus, 17(12), e99998. https://doi.org/10.7759/cureus.99998