Administering the experimental drug cinaciguat to aged mice for two weeks reduced blood concentrations of Alzheimer’s-associated amyloid-beta proteins by roughly half, according to research published in the Journal of Biological Chemistry.
Restoring Hepatic Filtration and Molecular Signaling
As mammals age, the liver undergoes pseudocapillarization, a process where fenestrations—tiny, sieve-like pores in the liver sinusoidal endothelial cells (LSECs)—shrink in size and number. This degradation hinders the liver’s ability to filter large macromolecules from the bloodstream.
The research team administered cinaciguat, a soluble guanylyl cyclase (sGC) activator that influences intracellular signaling, to 24-month-old mice at a daily dosage of 0.3 milligrams per kilogram of body weight for two weeks. Untreated aged mice and four-month-old young mice served as controls.
Treatment reopened the microvascular fenestrations in the aged mice, restoring cellular uptake capabilities. Blood plasma analysis revealed that concentrations of amyloid-beta40 (Aβ40), which were approximately twice as high in untreated old mice compared to young controls, dropped by about 50 percent following cinaciguat administration, reaching parity with the young control group (P=0.0047).
Unanticipated Reductions in Atherogenic Lipids
Beyond amyloid-beta proteins, the investigation tracked changes in low-density lipoprotein (LDL) cholesterol and oxidized LDL, both key risk factors for atherosclerosis and vascular inflammation. Untreated aged mice exhibited LDL concentrations roughly double those of young mice, while oxidized LDL levels were nearly 2.8 times higher.
Following the two-week drug regimen, both lipid metrics decreased significantly. Because LDL particles are small enough to pass through compromised liver fenestrations even during aging, researchers investigated further to explain the lipid clearance.
The investigation pointed to heparin-binding epidermal growth factor-like growth factor (HB-EGF), a signaling molecule secreted by LSECs that prompts neighboring hepatocytes to absorb LDL and amyloid-beta. While aged mice produced HB-EGF, their endothelial cells failed to secrete it properly. Cinaciguat restored HB-EGF secretion and normalized the surface expression of two critical clearance receptors on hepatocytes: the LDL receptor (LDLR) and low-density lipoprotein receptor-related protein 1 (LRP1).
“Wait, why did these levels drop?” Sam J. de Leve said, recalling the initial identification of the lipid reduction. “It clearly meant there was something else going on.”
Translational Hurdles and Future Preclinical Validation
The findings offer experimental proof that targeting hepatic function via the liver—which lacks the restrictive blood-brain barrier (BBB) that complicates direct central nervous system drug delivery—can alter circulating biomarker profiles.
However, the reduction of blood-borne Aβ40 does not directly demonstrate the clearance of cerebral amyloid plaques or the prevention of Alzheimer’s disease. The research team noted that further translational studies using dedicated animal models of Alzheimer’s disease are required to assess whether these peripheral clearances alter neurodegenerative disease progression.
“To see if these findings translate into novel therapies, further translational work is required,” Laurie D. DeLeve stated. “This aligns with epidemiological studies showing that advanced age is a major risk factor for Alzheimer’s disease and atherosclerosis, and that liver damage is also a risk factor for Alzheimer’s disease.”
Hepatic Microvascular Restoration in Aging Models
| Metric Evaluated | Untreated Aged Mice vs. Young Control | Effect of Cinaciguat Treatment |
|---|---|---|
| Plasma LDL Cholesterol | ~2x higher than young mice | Significant reduction |
| Oxidized LDL | ~2.8x higher than young mice | Significant reduction |
| LSEC Fenestrations | Reduced size and number | Restored structure and filtration capacity |
References
- Journal of Biological Chemistry: November 2026 issue.
