In a new commentary published in ChemBioChem, UC Santa Cruz professor Jevgenij Raskatov highlights research suggesting that this lesser-known peptide, called P3, can form microscopic clumps and threadlike structures known as fibrils. Evidence also suggests that P3 may interact with amyloid beta (Aβ), potentially influencing how it accumulates in the brain and how toxic it becomes. These findings raise the possibility that P3 contributes to the nerve cell damage associated with Alzheimer’s disease.

“The P3 peptide is, most likely, not the innocent bystander it was commonly thought to be. There’s still more research to be done. But this could turn Alzheimer’s research on its head,” said Raskatov, whose laboratory investigates amyloid peptides in hopes of identifying ways to prevent their harmful effects and develop better Alzheimer’s treatments. “P3 is a distinct aggregating peptide that is itself potentially neurotoxic and may be contributing to Alzheimer’s disease.”

Why Alzheimer’s Treatments Have Had Limited Success

Alzheimer’s is the most widespread neurodegenerative disease, affecting approximately 35 million people worldwide and generating annual costs exceeding $800 billion. The number of people living with the condition is expected to double by 2050.

Despite decades of intensive research, developing effective treatments has proved extraordinarily difficult. More than 400 clinical trials have investigated potential Alzheimer’s drugs, with most focusing on amyloid beta. Many of these efforts have failed, while others have produced only modest benefits. Some treatments have also been associated with serious complications, including brain hemorrhages and strokes.

Amyloid beta originates from a much larger protein embedded in cell membranes called the Amyloid Precursor Protein (APP). Two enzymes, β-secretase and γ-secretase, cut this protein in sequence, releasing amyloid beta peptides of different lengths.

Researchers have concentrated particularly on two versions, Aβ40 and Aβ42, which contain 40 and 42 amino acids, respectively. Aβ42 has attracted the greatest attention because it is especially prone to sticking together and forming toxic aggregates. As a result, it has remained a central target of Alzheimer’s drug development for decades.

Existing medications, including cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists, can temporarily ease certain symptoms but do not stop the disease from progressing. More recently, antibody treatments such as Lecanemab and Donanemab have been approved to help remove amyloid beta from the brain.

However, Raskatov argues that the benefits achieved so far remain limited, underscoring the need to investigate other biological processes involved in Alzheimer’s.

“Progress has been extremely slow, and the current state of the art in Alzheimer’s therapy leaves much to be desired,” he said. “We need fundamentally new approaches to the problem.”

The Overlooked Peptide That May Also Damage Brain Cells

Unlike amyloid beta, P3 forms when Amyloid Precursor Protein is processed through a different sequence of molecular cuts. In this pathway, an enzyme called α-secretase acts first, followed by γ-secretase.

Raskatov has proposed calling this peptide “Amyloid α,” or Aα, to better distinguish it from amyloid beta and reflect its ability to form aggregates.

For years, scientists largely assumed that P3 was incapable of forming amyloid deposits, was not toxic to cells, and would remain soluble in water. Under that interpretation, the peptide would simply dissolve rather than accumulate in the brain.

These assumptions were never adequately verified, according to Raskatov. Nevertheless, they helped establish the view that P3 was unlikely to matter in Alzheimer’s disease, leaving it largely absent from research efforts.

Raskatov, a specialist in peptide chemistry, and researchers in his laboratory decided to test those long-standing beliefs.

Over the past five years, the team has published three major studies demonstrating that P3 can form amyloid deposits at least as readily as amyloid beta. In fact, their experiments showed that P3 produces these aggregates more rapidly.

The researchers also found evidence that P3 itself may be harmful to neurons, although its toxicity appears lower than that of amyloid beta.

According to Raskatov, an independent research group in the United Kingdom has confirmed and expanded upon his team’s findings. Other laboratories are now beginning to investigate how P3 and amyloid beta interact, including whether their relationship affects the accumulation and toxicity of these peptides.

Together, the results challenge the long-held assumption that P3 is biologically harmless and irrelevant to Alzheimer’s. However, further research is needed to establish whether and how it contributes to the disease in patients.

Challenging Decades of Alzheimer’s Research

For much of the past several decades, amyloid beta has dominated scientific explanations of Alzheimer’s disease. David Teplow, an emeritus professor of neurology at UCLA and a prominent Alzheimer’s researcher, said the peptide has long been regarded as a central cause of the condition.

But an independent evaluation of Raskatov’s research led Teplow to conclude that scientists are beginning to reconsider this narrow focus.

“This reevaluation has far-reaching consequences for both basic science and clinical research into the causes and treatment of Alzheimer’s disease,” said Teplow, a founding editorial board member of the Journal of Molecular Neuroscience and the American Journal of Neurodegenerative Disease, as well as editor-in-chief of Progress in Molecular Biology and Translational Science.

Raskatov has also encountered a troubling problem while examining how other scientists have interpreted his team’s discoveries.

He identified at least four papers published in respected, peer-reviewed journals that cited his laboratory’s research as evidence that P3 was harmless and unable to form amyloid deposits. Yet his team’s experiments had demonstrated precisely the opposite.

“This is exactly the opposite of what we have actually shown,” Raskatov said. “We remain in the dark on how this sort of grand confusion may have come about. Clearly, there is more work ahead of us.”

The emerging evidence suggests that understanding Alzheimer’s may require looking beyond amyloid beta alone. By examining P3 and its interactions with other amyloid peptides, researchers hope to gain a more complete picture of the processes that damage brain cells and potentially identify new directions for treatment.

The remarkable discovery, described in 2024 in the journal Scientific Reports, came from fossils unearthed in Gujarat, western India. Researchers estimate that Vasuki measured between 10.9 and 15.2 meters (36 and 50 feet) long, although its exact size remains uncertain. Its enormous body and unusual evolutionary history offer a glimpse into a time when giant snakes inhabited the warm, tropical landscapes of ancient India.

Giant Snake Fossils Unearthed in India

Paleontologists Debajit Datta and Sunil Bajpai of the Indian Institute of Technology Roorkee identified the species from fossils recovered at the Panandhro Lignite Mine in Kutch, Gujarat. The remains date to the Middle Eocene, a period roughly 47 million years ago when Earth’s climate was considerably warmer than it is today.

The researchers examined 27 fossilized vertebrae, the individual bones that make up a snake’s backbone. Many were remarkably well preserved, and some remained connected in their original arrangement. The bones appear to have belonged to a fully grown animal.

The species was named Vasuki indicus in honor of Vasuki, the mythical serpent associated with the Hindu deity Shiva, who is traditionally depicted with the snake wrapped around his neck. The second part of the name refers to India, where the fossils were discovered.

How Big Was This Prehistoric Snake?

Although the scientists did not recover a complete skeleton, the preserved backbone provides important clues about the snake’s enormous proportions.

Individual vertebrae measured between 37.5 and 62.7 millimeters (1.48 and 2.47 inches) long and between 62.4 and 111.4 millimeters (2.46 and 4.39 inches) wide. Their unusually broad shape suggests that Vasuki possessed a thick, cylindrical body capable of supporting tremendous weight.

To estimate its total length, the researchers compared the fossilized bones with vertebrae from living snakes whose body lengths are known. Two different methods produced estimates ranging from 10.9 to 12.2 meters (36 to 40 feet) and 14.5 to 15.2 meters (48 to 50 feet).

Those measurements place Vasuki among the largest snakes ever identified. Its estimated length rivals that of Titanoboa, the giant snake that inhabited what is now Colombia approximately 60 million years ago and is thought to have reached around 13 meters (43 feet).

However, the researchers caution that their calculations involve considerable uncertainty. Different methods can produce substantially different estimates, particularly when scientists must reconstruct an extinct animal using an incomplete backbone. It remains unclear whether Vasuki actually exceeded Titanoboa in length.

A Massive Predator That Likely Hunted by Ambush

Despite its intimidating size, Vasuki probably was not a particularly fast or agile hunter.

The researchers suggest that its enormous body and distinctive vertebral structure would have favored relatively slow movement. Rather than actively chasing prey, the snake may have relied on ambush tactics, remaining concealed until another animal came within striking distance.

Its hunting behavior could have resembled that of modern anacondas and large pythons, which can overpower prey through constriction. These snakes use their muscular bodies to tighten around captured animals, interfering with circulation until the prey dies.

Scientists suspect Vasuki may have hunted in a similar way, although its precise diet and hunting behavior cannot be determined from the surviving fossils.

Its anatomy also suggests that the snake may have spent much of its time on land or in shallow, swampy environments, rather than living exclusively in water. The ancient landscape surrounding the fossil site contained wetlands and marshes that could have provided suitable habitat for an enormous ambush predator.

Ancient India’s Warm Climate May Have Helped Snakes Grow Enormous

The discovery also raises questions about why some prehistoric snakes reached sizes far beyond those of most species alive today.

During the Middle Eocene, the region where Vasuki lived experienced tropical conditions, with average temperatures estimated at approximately 28 degrees Celsius (82 degrees Fahrenheit).

Snakes are ectothermic animals, meaning they depend heavily on external sources of heat to regulate their body temperature. Warm environments can support the activity, digestion, and growth of large reptiles, potentially helping explain why exceptionally large snakes appeared during some of Earth’s warmer periods.

However, temperature alone does not determine how large a snake can become. Food availability, suitable habitat, evolutionary history, and other environmental factors also influence body size.

A Lost Lineage of Giant Snakes That Spread Across Continents

Beyond its extraordinary size, Vasuki provides evidence of an ancient branch of snake evolution.

The species belonged to Madtsoiidae, an extinct family of snakes that survived for roughly 100 million years, from the Late Cretaceous to the Late Pleistocene. Members of this group occupied regions including India, Africa, Europe, South America, and Australia.

Unlike modern anacondas and pythons, Vasuki represented a separate evolutionary lineage within this long-extinct family.

The researchers found that its closest relatives included Madtsoia pisdurensis, a fossil snake from ancient India, and Gigantophis garstini, another large prehistoric snake known from North Africa.

These relationships suggest that a lineage of giant madtsoiid snakes originated on the Indian subcontinent before spreading into other parts of the world.

As India moved northward and collided with Asia around 50 million years ago, changing geographic connections may have allowed these snakes to disperse through southern Eurasia, including southern Europe, and eventually into Africa during the Eocene, approximately 56 to 34 million years ago.

Later Fossil Discoveries Reveal an Ancient World Filled With Snakes

Research published in 2025 has added important context to the discovery of Vasuki.

In a study published in the Journal of Paleontology, Datta and Bajpai described additional fossil snakes from Eocene deposits in western India. Their findings revealed a surprisingly diverse community of ancient reptiles, including aquatic snakes, another large member of the madtsoiid family, and other extinct snake groups.

Among the discoveries was Pterosphenus rannensis, an ancient aquatic snake species that adds to scientists’ understanding of how these reptiles evolved and spread.

The researchers also identified another madtsoiid snake that appears to have shared a marshy environment with Vasuki. This suggests that the giant predator was part of a broader community of snakes occupying different ecological roles, rather than an isolated evolutionary oddity.

Evidence from the fossil deposits indicates that some of these snakes inhabited tidal environments, while others occupied swamps and marshes. Together, the discoveries paint a more detailed picture of the complex ecosystems that existed in India tens of millions of years ago.

What Modern Anacondas Reveal About Giant Snakes

Additional evidence about snake gigantism emerged from a separate 2025 study published in the Journal of Vertebrate Paleontology.

Researchers examining fossilized anaconda vertebrae from Venezuela found that these enormous snakes had already evolved large bodies by approximately 12.4 million years ago. Ancient anacondas reached estimated lengths of around 5.2 meters (17 feet), comparable to the size of many living anacondas.

The findings suggest that anacondas maintained their impressive size for millions of years, even as climates and ecosystems changed. They also show that prehistoric snakes did not necessarily grow larger simply because the planet was warmer.

Although anacondas are evolutionarily distinct from Vasuki, the research offers a useful comparison for understanding how different snake lineages became giants and adapted to their environments.

For Vasuki indicus, the full story remains incomplete. Its precise size, appearance, and behavior are still uncertain, but the fossil evidence establishes it as an extraordinary example of prehistoric gigantism.

Together with later discoveries from the same region, the ancient snake is helping scientists reconstruct a largely forgotten world in which massive serpents occupied the tropical landscapes of India.

In a study involving 194 patients, researchers found that a treatment using tiny particles that dissolve within hours was associated with substantial reductions in knee pain and improvements in mobility. The benefits persisted for at least 12 months, with 80% of patients assessed at the one-year follow-up reporting clinically meaningful pain relief.

The approach, known as genicular artery embolization, aims to interrupt the inflammation and abnormal blood vessel growth that contribute to chronic knee pain. Rather than replacing the damaged joint, doctors use a thin catheter to deliver microscopic particles directly into specific blood vessels.

The findings, published in the journal Radiology, suggest that this technique could provide another option for patients who have exhausted conventional treatments but cannot or do not want to undergo knee replacement surgery.

Why Knee Arthritis Is So Difficult To Treat

Osteoarthritis is the world’s most common form of arthritis and a major cause of disability. According to the World Health Organization, knee osteoarthritis affects more than 365 million adults worldwide.

The condition develops as cartilage, the protective tissue that cushions the ends of bones, gradually deteriorates. But osteoarthritis involves more than cartilage damage. Inflammation within the joint, changes in surrounding tissues, and increased sensitivity of pain signaling nerves can all contribute to persistent discomfort.

For many people, the consequences extend far beyond occasional knee pain. Everyday activities such as walking, climbing stairs, exercising, or standing for extended periods can become increasingly difficult.

Treatments typically begin with physical therapy, medication, and injections into the affected joint. When these approaches stop providing adequate relief, knee replacement surgery may eventually be considered. However, surgery is not appropriate or desirable for everyone.

“For many patients with knee osteoarthritis, there is a real treatment gap today,” said Florian Nima Fleckenstein, M.D., deputy head of Interventional Radiology Campus Mitte, Charité — Universitätsmedizin Berlin. “Conservative measures such as intra-articular injections no longer provide sufficient relief, but joint replacement is not an option for medical or personal reasons.”

A Different Way To Fight Knee Arthritis Pain

The treatment being investigated, genicular artery embolization (GAE), approaches knee arthritis from an unusual direction. Instead of focusing directly on damaged cartilage, it targets the abnormal blood vessels that develop around an inflamed joint.

These vessels can form within and around the synovium, a thin membrane lining the inside of the joint. As the vessels multiply, they can contribute to inflammation and encourage the growth of sensory nerves involved in transmitting pain.

GAE is designed to interrupt this process by reducing blood flow through the abnormal vessels while preserving the knee’s normal circulation.

During the procedure, an interventional radiologist inserts a thin catheter into an artery and carefully guides it toward the affected blood vessels. Tiny particles are then injected to block selected vessels, with the goal of reducing inflammation and pain.

The technique is called superselective embolization because doctors target specific small arteries rather than blocking circulation throughout the joint. It does not require an open surgical incision or replacement of the knee.

Researchers have previously investigated both temporary blocking agents and permanent microscopic particles. Each approach has potential drawbacks, including differences in how precisely the particles can be delivered and how long they remain inside the blood vessels.

For this study, the team examined rapidly resorbable, gelatin-based microspheres. These precisely sized, spherical particles are engineered to dissolve within hours, potentially combining the advantages of temporary agents with the controlled delivery of permanent microspheres.

“GAE is a whole new treatment regimen that targets abnormal hypervascularity around the joint and, in turn, modulates the pathological neurovascular environment,” Dr. Fleckenstein said.

Hypervascularity refers to an unusually high concentration of blood vessels. The pathological neurovascular environment describes the abnormal interactions between those vessels and pain signaling nerves in the affected tissue.

“By reducing both inflammation and pain, GAE with resorbable microspheres may be the first procedure that alters the course of the disease, slowing its progression.”

Whether the procedure can actually slow osteoarthritis progression remains an open question. Although reducing inflammation could theoretically influence the disease, the study did not demonstrate that GAE prevents cartilage deterioration or reverses existing joint damage.

Nearly 200 Patients Underwent the Procedure

To evaluate the approach, researchers conducted a prospective single-center study involving 194 patients with osteoarthritis-related knee pain. The participants included 114 women and 80 men, with a median age of 69 years and a median body mass index of 28.4.

All had continued to experience symptoms despite at least three months of conventional care, including physical therapy, anti-inflammatory medications, and injections into the knee.

“We believe these results carry real weight because they come from real-world data,” Dr. Fleckenstein said. “With this broad, inclusive study design, our participants are exactly the patients that physicians encounter every day in their practices.”

The procedures took place between July and November 2024. Forty-five participants (23%) had osteoarthritis affecting both knees and received two separate treatments, with the second performed within four weeks of the first.

Altogether, the researchers carried out 239 GAE procedures.

Doctors used real-time X-ray imaging, known as fluoroscopy, to guide the catheter and deliver the particles to the targeted arteries. All 239 procedures were technically successful, meaning the intended blood vessels were successfully treated.

The safety findings were also encouraging. No moderate or severe adverse events were recorded, and mild, temporary complications occurred in 6.7% of procedures.

These included brief skin discoloration near the treated area and one superficial collection of blood near the catheter insertion site. All resolved without lasting complications.

Knee Arthritis Pain Dropped and Stayed Lower for a Year

The researchers monitored pain, movement, and quality of life before treatment and at several intervals afterward. Assessments were conducted at six weeks, three months, six months, and 12 months. An orthopedic surgeon also examined patients in person at the six-month follow-up.

Participant retention remained relatively high throughout the study. Follow-up rates were 94% at six weeks (183/194), 89% at three months (172/194), 89% at six months (171/194), and 79% at 12 months (154/194).

The most striking finding was the sustained reduction in knee pain.

Using the Numeric Rating Scale (a 0-to-10 measure of pain intensity), median pain scores fell from 7 before treatment to 4 after six weeks. By six months, the median score had declined to 3, and it remained at that level at the 12-month follow-up.

That represents a reduction of more than half from the original median pain score, with benefits that were still apparent a full year after treatment.

“In our cohort, we saw a significant drop in pain and a significant increase in function, including sports and recreation and daily activity,” Dr. Fleckenstein said. “Most importantly, their quality of life significantly increased.”

Patients Also Reported Better Mobility and Quality of Life

The improvements extended beyond pain reduction. Researchers used the Knee Injury and Osteoarthritis Outcome Score, a standardized questionnaire that evaluates how knee problems affect symptoms, mobility, recreation, and everyday life.

Across all five areas assessed, patients reported meaningful progress during the year following treatment.

Median scores for daily activities increased from 53 to 71.5, suggesting that routine movements such as walking and climbing stairs became easier. Sports and recreation scores climbed from 15 to 36, indicating improvements in more physically demanding activities.

Scores measuring osteoarthritis symptoms rose from 51 to 68, while the pain category improved from 44 to 65 (where 0 indicates extreme knee pain and 100 indicates no pain at all).

Quality of life scores also increased substantially, rising from 19 before treatment to 40 after 12 months.

To determine whether these changes were large enough to matter to patients, the researchers applied established thresholds for clinically meaningful improvement.

Previous studies have identified a reduction of at least 2.0 points on the Numeric Rating Scale and an increase of at least 10 points in the Knee Injury and Osteoarthritis Outcome Score categories as meaningful improvements.

These thresholds are known as the minimum clinically important difference. In simple terms, they distinguish changes that are likely to be noticeable in daily life from smaller statistical differences that may have little practical significance.

At 12 months, 80% of participants who completed the pain assessment exceeded the clinically meaningful improvement threshold.

“Our study demonstrates that GAE using rapidly resorbable gelatin-based microspheres is a safe, minimally invasive therapy that provides meaningful pain relief and functional improvement in participants with osteoarthritis-related knee symptoms for at least 12 months,” Dr. Fleckenstein said. “By embolizing the pathological vessels, we’re able to normalize the vessel structure — and, in turn, the neuronal structure of the knee.”

What Other Studies Reveal About Knee Artery Embolization

The results add to a growing body of evidence investigating whether blocking abnormal knee blood vessels can offer sustained relief from osteoarthritis.

A randomized study published in Clinical Radiology in 2026 provided encouraging findings. Researchers compared GAE combined with standard care against standard care alone in 50 patients. After one year, pain scores had improved by 72.7% in the embolization group, compared with 24.2% in the standard care group. The treated patients also reported better knee function.

However, that study used polyvinyl alcohol particles rather than the dissolving gelatin particles examined by Fleckenstein’s team. It also did not include a sham procedure, making it difficult to separate the treatment’s physical effects from patients’ expectations.

Other research has raised important questions about how much of the improvement is caused by embolization itself.

A randomized, sham-controlled study published in European Radiology in April 2026 followed 58 patients for 12 months. Both the GAE and sham treatment groups experienced sustained reductions in pain, but researchers found no statistically significant difference between them. MRI examinations also failed to identify a significant reduction in joint inflammation attributable to embolization.

Similarly, an analysis appearing in the September 2026 issue of the European Journal of Radiology examined 22 studies involving 633 patients. Although pain scores often improved substantially after treatment, the researchers found no statistically significant advantage over sham procedures when results from three randomized trials were combined.

A separate June 2026 analysis of 45 studies involving 2,205 patients also documented improvements in pain and function, but judged the overall certainty of the evidence to be low or very low.

Together, these findings suggest that GAE is associated with promising improvements, particularly in observational studies, but more rigorous trials are needed to establish how much benefit comes directly from blocking the blood vessels.

Could This Treatment Help Patients Avoid Knee Replacement?

Despite the remaining uncertainties, researchers and medical specialists are increasingly exploring GAE as a possible option for patients who have limited alternatives.

In a 2026 position statement, the Society of Interventional Radiology supported offering the procedure to appropriately selected patients whose symptoms persist despite conservative treatment, particularly those who cannot undergo or wish to delay knee replacement surgery.

The society also emphasized the importance of specialist training, careful patient selection, and continued clinical trials to establish the treatment’s effectiveness and long-term safety.

The study led by Fleckenstein provides particularly valuable information about rapidly resorbable gelatin microspheres. With nearly 200 participants, it represented the largest published clinical investigation of this specific approach at the time.

Still, because the study did not include an untreated or sham treatment comparison group, it cannot establish how much of the observed improvement resulted directly from the procedure. The researchers also did not evaluate whether the treatment slows cartilage loss or prevents patients from eventually needing joint replacement.

Longer follow-up and larger controlled trials will be essential to determine how durable the benefits are, which patients respond best, and whether dissolving particles offer advantages over other embolization materials.

For patients whose knee arthritis continues to interfere with everyday life despite medication, therapy, and injections, the approach nevertheless represents an increasingly studied possibility.

“This lets us speak about safety and efficacy with real confidence,” Dr. Fleckenstein said. “For the right patient, it can mean lasting relief from a single, minimally invasive procedure — a meaningful new option between injections and joint replacement.”