Breakthrough study shows Alzheimer’s may be reversible by restoring brain energy

Alzheimer’s disease, long regarded as an irreversible condition, may not be permanent after all, according to a new study that demonstrates recovery of memory and brain function in animal models.

Researchers have found that a severe collapse in the brain’s energy system plays a central role in driving Alzheimer’s disease. By restoring this energy balance, scientists were able to repair brain damage, reverse disease pathology and restore cognitive function in mice, even at advanced stages of the illness.

The study, conducted by researchers from University Hospitals, Case Western Reserve University and the Louis Stokes Cleveland VA Medical Center, challenges more than a century of scientific thinking around Alzheimer’s. Until now, treatment strategies have largely focused on prevention or slowing progression, as no clinical trials have ever aimed to reverse the disease and recover lost cognition.

The research, led by Kalyani Chaubey, PhD, of the Pieper Laboratory, was published on December 22 in Cell Reports Medicine. By analysing human Alzheimer’s brain tissue alongside multiple mouse models, the team identified a critical failure involving NAD+, a molecule essential for cellular energy production.

The scientists found that NAD+ levels decline sharply in Alzheimer’s brains, far more than during normal ageing. This energy collapse disrupts essential cellular functions and contributes directly to neurodegeneration. Importantly, restoring NAD+ balance not only prevented Alzheimer’s in mice but also reversed the disease after it had already progressed.

To study the condition, researchers used genetically engineered mice that mimic key features of human Alzheimer’s, including amyloid and tau abnormalities. These mice developed widespread brain damage, including inflammation, nerve fibre degeneration, impaired neuron formation in the hippocampus, breakdown of the blood-brain barrier and severe memory loss.

The team tested whether restoring NAD+ balance after disease onset could repair this damage. Using a pharmacological compound known as P7C3-A20, developed in the Pieper laboratory, researchers observed dramatic results.

Mice treated at advanced stages of the disease showed repair of major brain abnormalities and complete recovery of learning and memory. Blood tests also showed normalisation of phosphorylated tau 217, a clinically approved biomarker used in diagnosing Alzheimer’s in humans.

"We were very excited and encouraged by our results," said Andrew A. Pieper, MD, PhD, senior author of the study and Director of the Brain Health Medicines Center, Harrington Discovery Institute at UH. "Restoring the brain's energy balance achieved pathological and functional recovery in both lines of mice with advanced Alzheimer's.

Seeing this effect in two very different animal models, each driven by different genetic causes, strengthens the idea that restoring the brain's NAD+ balance might help patients recover from Alzheimer's."

Highlighting the broader implications, Dr. Pieper added, "The key takeaway is a message of hope -- the effects of Alzheimer's disease may not be inevitably permanent. The damaged brain can, under some conditions, repair itself and regain function."

Dr. Chaubey noted that the findings also point towards potential markers for future human trials. "Through our study, we demonstrated one drug-based way to accomplish this in animal models, and also identified candidate proteins in the human AD brain that may relate to the ability to reverse AD."

Researchers cautioned against equating this approach with commercially available NAD+ supplements. According to Dr. Pieper, such supplements can raise NAD+ levels excessively and may increase cancer risk in animal studies. In contrast, P7C3-A20 helps cells maintain healthy NAD+ balance without exceeding normal limits.