Rejuvenated Liver Cells Cut Alzheimer's-Linked Amyloid by Half in Animal Models

An experimental drug has successfully reversed key hallmarks of aging in the liver cells of older rats, restoring their ability to filter harmful proteins from the bloodstream. After a 14-day course of the treatment, circulating levels of amyloid beta—the protein that forms plaques in Alzheimer's disease—fell by roughly 50 percent.[1][2]

The study, published on September 26, 2026, in the Journal of Biological Chemistry, also revealed an unexpected cardiovascular benefit. Levels of low-density lipoprotein, commonly known as "bad" cholesterol, dropped to concentrations typically seen in young animals.[4]

Researchers at the Keck School of Medicine of the University of Southern California (USC) led the investigation, focusing on a specialized population of cells that line the liver's blood vessels. These liver sinusoidal endothelial cells act as a biological sieve, allowing the organ to clear waste from the body.[3][4]

"We need to do further translational work to see whether our findings might point to new therapies," said Laurie DeLeve, a professor at the USC Department of Medicine and the study's corresponding author. "We're hopeful, though, because the findings line up with a lot of epidemiological results showing age as a major risk factor for Alzheimer's and atherosclerosis."[3]

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Reopening the liver's microscopic pores

In a healthy, young liver, the endothelial cells are riddled with microscopic pores called fenestrae. These openings allow large macromolecules in the blood to pass through to the hepatocytes, which are the liver's primary working cells responsible for processing and clearing them.[2]

As mammals age, this biological sieve gradually fails. The pores shrink and close up in a process known as pseudocapillarization, leaving larger molecules stranded in the bloodstream. Much of the amyloid beta in the blood travels bound to large fat-carrying particles that cannot easily pass a closed sieve.[4]

To reverse this decline, the USC team administered an experimental compound called cinaciguat to aged rats at a dose of 0.3 milligrams per kilogram daily. The drug is a soluble guanylate cyclase activator designed to stimulate specific cellular pathways that degrade over time.

The treatment fully restored the structure of the aging filter cells, reopening their pores. Consequently, the circulating amyloid beta 40 in the treated older rats was cut in half, matching the levels measured in young rats, while untreated aged rats showed no such improvement.[2]

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An unexpected drop in cholesterol

The researchers initially included low-density lipoprotein (LDL) as a control measure, expecting it to remain unchanged. LDL particles are relatively small, measuring just 20 to 30 nanometers across, meaning they can slip through the liver's vessel lining even when the pores have closed.

Instead, the age-related increases in LDL reversed entirely, dropping to youthful levels alongside the amyloid beta. This surprise prompted the team to investigate secondary mechanisms, leading to the discovery of a previously unknown biochemical chain reaction between different types of liver cells.[2]

They found that cinaciguat activates a molecular messenger in the endothelial cells, which then release a specific growth factor known as HB-EGF. Before treatment, the necessary cyclic GMP messenger in the aged rats was about 60 percent lower than in their younger counterparts.

Once stimulated by HB-EGF, the hepatocytes regain their ability to grab onto both LDL and amyloid beta circulating in the blood. The treatment effectively reversed the age-associated loss of specific surface receptors on the hepatocytes, restoring their clearance capacity.

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Bypassing the blood-brain barrier

If the liver proves to be an effective lever against Alzheimer's disease, it could fundamentally alter how pharmaceutical companies approach neurological drug development. Treatments aimed directly at the brain currently face an estimated 98 percent failure rate in clinical trials.[3]

The primary obstacle for these failed neurological drugs is the blood-brain barrier, a highly selective membrane that blocks most therapeutic molecules from reaching brain tissue. Targeting the liver offers a peripheral route that avoids this barrier entirely.[1][3]

"Rather than trying to get a drug through the blood-brain barrier, which is obnoxiously difficult, we could direct drugs to the liver," said Sam de Leve, the study's first author. "An organ where there might be more therapeutic impact and certainly an easier job of drug delivery."[3]

Epidemiological research has long established liver damage as a distinct risk factor for Alzheimer's disease. By proving that the liver's age-related loss of clearance capacity is reversible with a short course of treatment, the USC team has provided a mechanistic link to support those population-level observations.[2]

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The path to human trials

While the results demonstrate that a single drug can act on both the liver's filter and its working cells, the findings remain limited to animal models. Lowering amyloid beta in the bloodstream does not automatically prove that harmful plaques in the brain will decrease.[2][4]

The research team compared three distinct groups during the study: aged rats treated for two weeks, untreated aged rats, and untreated young rats. They plan to continue their work in rodents to determine whether the reduction in circulating amyloid beta translates into measurable neurological protection.[4]

"There are six different ways someone could go with this, and we can't do them all," Sam de Leve noted, inviting other scientific disciplines to build on the discovery. "So please, scoop us. We'd love it."