Related Experiment Video
Updated: May 27, 2026
07:29
Deep Vascular Imaging in the Eye with Flow-Enhanced Ultrasound
Published on: October 4, 2021
Astaxanthin increases choroidal blood flow velocity
Michiyuki Saito1, Kazuhiko Yoshida, Wataru Saito
1Department of Ophthalmology, Hokkaido University Graduate School of Medicine, Nishi-7-chome, Kita 15-jou, Kita-ku, Sapporo 060-8638, Japan.
Summary
Daily astaxanthin (AXT) supplementation for four weeks significantly increased choroidal blood flow velocity in healthy adults. This study demonstrates AXT
Area of Science:
- Ophthalmology
- Nutrition Science
- Medical Research
Background:
- Astaxanthin (AXT) is known for its antioxidant and anti-inflammatory properties.
- Previous research suggests AXT may influence blood transit times.
- Choroidal circulation hemodynamics can be assessed noninvasively using laser speckle flowgraphy (LSFG).
Purpose of the Study:
- To evaluate the effect of continuous daily astaxanthin (AXT) ingestion on quantitative blood flow velocity.
- To determine if 12 mg of AXT daily for four weeks can increase choroidal blood flow.
- To assess the safety of AXT supplementation in healthy volunteers.
Main Methods:
- A randomized, double-blind, placebo-controlled study involving 20 healthy volunteers.
- Participants ingested either 12 mg of AXT or a placebo daily for four weeks.
- Laser speckle flowgraphy (LSFG) measured blood flow velocity (via SBR) at baseline, 2 weeks, and 4 weeks.
Main Results:
- A significant increase in macular SBR (blood flow velocity) was observed after four weeks of AXT ingestion (P=0.018).
- No significant changes in macular SBR were found in the placebo group (P=0.598).
- No adverse events were reported during the study period.
Conclusions:
- Four weeks of daily astaxanthin (AXT) administration can enhance choroidal blood flow velocity.
- The study suggests AXT is a safe supplement for improving ocular hemodynamics.
- These findings support the potential of AXT in managing conditions related to impaired blood flow.
Related Concept Videos
01:17Autoregulation of Blood Flow
Autoregulation mechanisms are characterized by their inherent capacity for self-regulation without necessitating specific nervous stimulation or endocrine control. These mechanisms facilitate the adjustment of blood flow and, therefore, perfusion specific to each tissue region. This self-regulation encompasses chemical signals and myogenic controls.
Chemical Signaling in Autoregulation
Chemical signaling operates at the precapillary sphincter level, inciting either contraction or relaxation.
Chemical Signaling in Autoregulation
Chemical signaling operates at the precapillary sphincter level, inciting either contraction or relaxation.
01:29Blood Flow
Blood is pumped by the heart into the aorta, the largest artery in the body, and then into increasingly smaller arteries, arterioles, and capillaries. The velocity of blood flow decreases with increased cross-sectional blood vessel area. As blood returns to the heart through venules and veins, its velocity increases. The movement of blood is encouraged by smooth muscle in the vessel walls, the movement of skeletal muscle surrounding the vessels, and one-way valves that prevent backflow.
01:24Regulation of Angiogenesis and Blood Supply
Rapidly dividing tumors, embryos, and wounded tissues require more oxygen than usual, lowering the oxygen concentration in the blood. At low oxygen or hypoxic conditions, an oxygen-sensitive transcription factor called the hypoxia-inducible factor 1 or HIF1 is activated. HIF1 is a dimeric protein of alpha (ɑ) and beta (β) subunits. Under optimal oxygen conditions, HIF1β is present in the nucleus while HIF1ɑ remains in the cytosol. HIF1ɑ is hydroxylated by prolyl hydroxylase and factor...
01:20Exercise and Cardiovascular Response
Exercise significantly impacts cardiovascular response, which is crucial for understanding patient health and designing effective treatment plans.
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
Light to moderate physical activity initiates a series of interconnected responses in the body. The heart rate modestly increases in anticipation of the workout, followed by widespread vasodilation as oxygen consumption by skeletal muscles increases. This results in decreased peripheral resistance, increased capillary blood flow, and accelerated...
01:27Open Angle Glaucoma: Treatment
In open-angle glaucoma, the iridocorneal angle remains open, but the trabecular meshwork becomes stiff, slowing down the outflow of aqueous humor. This causes a buildup of aqueous humor in the anterior chamber, leading to a sudden increase in intraocular pressure. The treatment for open-angle glaucoma focuses on reducing the elevated intraocular pressure by either decreasing the secretion of aqueous humor or increasing its outflow.
Drugs such as carbonic anhydrase inhibitors, α2- and...
Drugs such as carbonic anhydrase inhibitors, α2- and...