Sea Cucumber Fucoidan Eases Atherosclerosis in Mice by Rewiring Cholesterol Traffic

A sulfated sugar molecule harvested from an unglamorous sea cucumber may be one of the more unexpected players in the fight against clogged arteries. In a study published in Frontiers in Nutrition, researchers in China report that fucoidan extracted from the sea cucumber Pearsonothuria graeffei — a species prized more for its functional chemistry than its flavor — significantly eased dyslipidemia and shrank aortic plaques in a classic mouse model of atherosclerosis. The work goes beyond simply documenting a benefit: it traces a detailed molecular itinerary showing how the compound reroutes cholesterol through the intestine and liver, offering a mechanistic blueprint for why this marine polysaccharide keeps showing up in metabolic research.

Atherosclerosis, the slow accumulation of lipid-rich plaques inside artery walls, remains a leading driver of heart attacks and ischemic stroke. Two forces dominate its progression: chronically elevated cholesterol and persistent low-grade inflammation. When a high-fat diet floods the bloodstream with triglyceride-rich lipoproteins, these particles lodge in the vascular endothelium, triggering inflammatory signals that recruit immune cells. Monocytes differentiate into macrophages, which engulf lipids and swell into foam cells — the cellular hallmark of early arterial lesions. Current lipid-lowering drugs, including statins, ezetimibe, and PCSK9 inhibitors, have transformed cardiovascular care, but they carry limitations: statins can burden the liver, and ezetimibe’s effect is comparatively modest. That gap has pushed researchers toward dietary bioactives that could complement or reduce reliance on pharmaceuticals.

Fucoidan, a fucose-based polysaccharide studded with sulfate groups, is found in brown seaweeds and marine invertebrates. It has attracted attention for anti-inflammatory, lipid-lowering, and immune-modulating properties, with a generally favorable safety profile. Prior work by the same team had already shown that fucoidan from Pearsonothuria graeffei (Fuc-Pg) could reshape gut microbiota and dampen intestinal and colonic inflammation in obese mice. But whether it could slow atherosclerosis itself — and by what route — remained unresolved. The new study set out to answer both questions in a single experimental framework.

The researchers used ApoE-deficient mice, a standard model in which the absence of apolipoprotein E makes animals exquisitely vulnerable to diet-induced arterial plaques. Thirty-two of these mice were fed a high-fat diet containing 42% of calories from fat and 1.5% cholesterol for twelve weeks. They were divided into four groups: an untreated model group, a group receiving 20 mg/kg of simvastatin, and two groups receiving Fuc-Pg at 20 or 80 mg/kg by daily oral gavage. Eight normal C57BL/6J mice on a standard diet served as healthy controls. At the end of the trial, the team collected blood, liver, aorta, and small intestine for biochemical, histological, and molecular analysis.

The results were striking. Untreated ApoE-deficient mice on the high-fat diet gained significantly more weight and developed the expected dyslipidemic signature: elevated total cholesterol, triglycerides, and LDL-C, with depressed HDL-C. High-dose Fuc-Pg markedly reversed this pattern, lowering TC, TG, and LDL-C more effectively than the low dose. Notably, simvastatin — the positive control — failed to improve the lipid profile in these mice, a result consistent with earlier reports that statin efficacy can be blunted under a heavy dietary fat load and may depend on functional ApoE protein, which these mice lack. Oil Red O staining of the aorta told a similar story: untreated mice showed extensive red plaques from the aortic arch to the abdominal aorta, while high-dose Fuc-Pg produced a statistically significant reduction in plaque area, particularly in the aortic arch.

Inflammation, a key accelerant of plaque growth, also receded under Fuc-Pg treatment. Serum levels of the pro-inflammatory cytokines IL-1β and TNF-α, along with the chemokine MCP-1, were substantially elevated in the model group but dropped sharply with Fuc-Pg intervention. Hepatic mRNA levels of IL-1β and TNF-α followed the same trend. Simvastatin, by contrast, showed no meaningful effect on these inflammatory markers, underscoring that Fuc-Pg’s benefit extends beyond lipid numbers alone.

To understand how the compound works, the team turned to the intestine — the first checkpoint for dietary fat. Enterocytes absorb fatty acids and cholesterol and package them into chylomicrons, lipoprotein particles that enter the lymphatic system and eventually the bloodstream. Two proteins are central to this process: CD36, a fatty acid transporter on the cell surface, and microsomal triglyceride transfer protein (MTP), which assembles dietary lipids into pre-chylomicron particles. In the duodenum of untreated mice, both CD36 and MTP were markedly upregulated. High-dose Fuc-Pg suppressed both, effectively throttling the assembly line that converts a fatty meal into circulating lipid cargo. The team also observed increased fecal excretion of cholesterol and triglycerides, confirming that less dietary lipid was being absorbed and more was passing through the gut unprocessed.

In the liver, Fuc-Pg shifted cholesterol traffic in the opposite direction — toward export. Reverse cholesterol transport (RCT) is the process by which excess cholesterol from peripheral tissues is returned to the liver for elimination, either through biliary secretion or conversion into bile acids. The hepatic LDL receptor (LDLR), which clears more than 70% of circulating LDL particles from the blood, was upregulated at both mRNA and protein levels with Fuc-Pg treatment. The ABCG5/ABCG8 transporter pair, which pumps cholesterol from hepatocytes into bile, was also elevated. Together, these changes suggest that Fuc-Pg helps the liver pull cholesterol out of circulation and push it toward excretion, relieving the hepatic lipid deposition that otherwise fuels dyslipidemia and arterial disease.

The third arm of the mechanism involves bile acids. Cholesterol converted into bile acids represents one of the body’s main routes for disposing of excess sterol. Fuc-Pg increased hepatic total bile acid levels and boosted the expression of CYP7A1 and CYP27A1 — the rate-limiting enzymes of the classic and alternative bile acid synthesis pathways, respectively. Upstream, the compound elevated PGC1α and HNF4α, nuclear regulators that synergistically activate CYP7A1 transcription. Mass spectrometry profiling revealed shifts in the bile acid pool, including a notable rise in tauroursodeoxycholic acid (TUDCA), which protects hepatocytes from endoplasmic reticulum stress and apoptotic signaling, and tauro-beta-muricholic acid (TβMCA), a hydrophilic species that dilutes the toxicity of more hydrophobic bile acids. Meanwhile, serum bile acid levels trended downward rather than spiking — a reassuring sign that the liver was handling the increased synthetic load without leaking bile acids into circulation, which would indicate injury.

The study is not without caveats. The ApoE-deficient mouse model, while classic, does not fully recapitulate human atherosclerotic pathology, and the simvastatin control’s underperformance — likely a quirk of the model rather than a flaw in statins themselves — complicates direct comparisons with clinical practice. Still, the findings position Fuc-Pg as a structurally well-characterized marine polysaccharide with a coherent, multi-organ mechanism: it throttles lipid entry at the gut, accelerates cholesterol clearance in the liver, and funnels the surplus into bile acid synthesis for safe elimination. For a field hungry for dietary strategies that complement existing drugs, that combination of specificity and mechanistic depth makes sea cucumber fucoidan a compound worth watching as research moves from mouse models toward functional food applications.

Subject of Research: atherosclerosis

Article Title: Fucoidan from Pearsonothuria graeffei alleviates dyslipidemia in ApoE−/− mice by regulating reverse cholesterol transport and promoting bile acid synthesis

Article References: Zhao, T., Yu, Y., Wang, Y., Zhang, L., Xiao, J., Chen, S., & Li, S. (2026). Fucoidan from Pearsonothuria graeffei alleviates dyslipidemia in ApoE−/− mice by regulating reverse cholesterol transport and promoting bile acid synthesis. Frontiers in Nutrition, 13, 1974149. https://doi.org/10.3389/fnut.2026.1974149

Image Credits: AI Generated

DOI: 10.3389/fnut.2026.1974149

Keywords: fucoidan, atherosclerosis, cholesterol metabolism, bile acids, reverse cholesterol transport, sea cucumber, dyslipidemia, functional foods, Pearsonothuria, graeffei, alleviates, ApoE