New Research Highlights Combination Therapy and Molecular Pathways in Alzheimer's Disease

Two separate studies published in peer-reviewed journals have revealed new approaches to understanding and treating Alzheimer's disease. One study shows that combining existing anti-amyloid antibody therapies with small molecules from common foods may improve effectiveness and safety, while another research effort has mapped a molecular cause-effect cascade that could identify new therapeutic targets.

Researchers from the University of Waterloo's School of Pharmacy found that pairing amyloid-targeting antibodies already used in clinical treatment with small molecules that also disrupt amyloid buildup leads to greater inhibition of amyloid-beta aggregation. The combination more effectively neutralized the harmful protein clumps than either approach alone. The antibodies used in the study were aducanumab and lecanemab, and the small molecules were resveratrol and curcumin, which are found in foods such as grapes, berries, peanuts, and turmeric. The combination could potentially allow clinicians to use lower doses of antibodies, reducing the risk of serious treatment-related side effects like brain swelling and bleeding. The study was published in the journal ACS Chemical Neuroscience.

Alzheimer's disease is the leading cause of dementia. Nearly 750,000 people in Canada are living with dementia, a number expected to reach one million by 2030. Anti-amyloid antibody therapies can slow disease progression but carry potentially serious side effects, highlighting the need for safer treatment options. The research team stresses that these findings do not mean people should take resveratrol or curcumin supplements to prevent or treat dementia, as reaching the brain would require unsafe amounts. The next stage of the work will focus on creating next-generation drugs that can enter the brain more effectively and work alongside antibody treatments.

A separate study published in Molecular Psychiatry reveals a path of cause-effect molecular events that can lead to Alzheimer's disease. Researchers at Baylor College of Medicine, Duncan Neurological Research Institute at Texas Children's Hospital, and collaborating institutions integrated postmortem human brain gene expression analyses with laboratory fruit fly studies. The Accelerating Medicines Partnership (AMP)-AD target discovery consortium analyzed about 2,000 postmortem brain tissue samples and identified 30 AD-associated gene expression networks. The association was particularly robust for genes involved in immune and synaptic regulatory mechanisms.

Using fruit flies as a model system, the researchers tested 344 genes whose expression was altered in brains with Alzheimer's disease. They found that immune response genes with increased expression promoted neurodegeneration, suggesting these genes may play a causal role. An unexpected finding emerged around synaptic genes: the activity of these genes is reduced in Alzheimer's brains, but when researchers silenced similar genes in fruit flies, the brain cells were protected from death. This suggests the reduced expression may represent a compensatory response to damaging brain cell hyperactivity.

The team proposes a "biphasic" or two-stage model connecting cause-effect events leading to Alzheimer's. Early in the disease, amyloid plaques may trigger an initial increase in synaptic genes that hyperactivate brain cells, contributing to damage. Later, tau tangles appear to reduce the expression of these same genes as a protective response, but this appears to be "too little, too late" as brain function deteriorates further leading to dementia. This molecular cascade pinpoints specific driver genes and pathways worthy of further study as potential therapeutic targets.