What is Prion Disease?

Prions are unusual disease-causing agents — they’re not bacterial, viral, or parasitic. They’re not alive — and there’s no good explanation as of yet for why they exist.

A prion is a protein. The word is derived from the proteinaceous infectious particle. Prion proteins are naturally occurring throughout the brain (PrP^c), but their function isn’t well understood. Normally, these proteins are water-soluble and are broken down by enzymes known as proteases in the brain.

Diseased prions can make their way into the brain where they self-replicate by converting healthy prions into diseased ones.

These new proteins are resistant to protease, so cannot be broken down in the brain. When this happens, we start to develop “broken” proteins in the brain that we can’t get rid of. These proteins crowd areas of the brain, and since they have nothing to offer, the brain starts to decay over time.

It can take many years to begin showing symptoms.

How Does Prion Disease Work?

Initial research on prion disease discovered that the infectious agents responsible were lacking a nucleic acid genome — all previously infectious agents, including bacteria and viruses, used nucleic acids to replicate themselves.

Since prions don’t have these, it wasn’t clear how they were able to reproduce themselves in the brain.

It wasn’t until later that researchers discovered that prion diseases were caused by misshapen proteins, which would bind to other proteins and cause them to change shape as well. Prions spark a chain reaction of converting healthy proteins to unhealthy proteins that gradually spread throughout the brain — eventually leading to extensive, irreversible damage.

Where Do Prions Come From?

Before the 1950s, we had no idea what caused neurodegenerative disorders such as Creutzfeldt-Jakob Disease (CJD or “mad cow disease”).

Incidences were random, and disease progression was mysterious — leading researchers down dead ends with every attempt to understand the condition.

Sometime in the 1950s, everything changed. Researchers identified a disease among the Fore tribe in Papua New Guinea with symptoms very similar to CJD. It was identified that the disease was transmitted during a funeral ritual practiced by the tribe involving cannibalism of the brains of deceased tribe members.

Researchers noticed that some of the tribe members that were deceased had extensive brain damage (encephalopathy). Extracts made from brain samples were injected into monkeys — resulting in very similar symptoms. It was at this point that prion disease was discovered to spread through the ingestion of infected brain matter.

Other, more complex interactions may be involved as well, such as co-infection with a virus that interacts with the protein symbiotically (called the virino hypothesis), but this theory has contradictions and requires more research.

The cause and progression of prion disease are still heavily debated in the medical community, but it’s been rapidly progressing over the past five decades.

It’s now believed that prion disease starts through random mutation, which may or may not be passed on genetically. If prions from the brain get into another member of the same species, they can become infectious, propagating in the brain of those infected with the protein.

The Dangers of Prion Disease

Prion disease usually begins after eating food contaminated with the misshapen protein. In the bloodstream, the prion doesn’t pose much threat to the body, and in most cases, the body can get rid of them safely.

However, in some cases, these prions end up in places such as the spleen, peripheral neurons, or the brain, where they can cause serious long-term problems.

Ultimately, as the misshapen proteins self-replicate and spread through the brain, they kill the neurons, leaving large holes in the brain and making it look like a sponge. The scientific name for this is spongiform encephalopathy. For this reason, most prions are considered transmissible spongiform encephalopathies (TSEs).

There are a few other neurological conditions driven by misshapen proteins in the brain:

• Alzheimer’s disease
• Parkinson’s disease
• Huntington’s disease
• Spinocerebellar ataxias
• Amyotrophic lateral sclerosis (ALS)
• Diffuse Lewy body dementia
• Frontotemporal dementias

Interestingly, CBD has been shown to slow the progression of several of these neurological conditions.

Misfolded proteins in the brain are devastating in the long term, leading to gradual neurological deficits, loss of muscle control, and death.

Side Effects of Prion Disease

• Fatigue
• Difficulty speaking
• Difficulty walking and changes in gait
• Confusion
• Hallucinations
• Insomnia
• Muscle tremors
• Muscle stiffness
• Rapidly developing dementia

List of Known Human Prion Diseases

• CJD (mad cow’s disease)
• Gerstmann-Straussler-Scheinker syndrome
• Variant CJD
• Variably protease-sensitive prionopathy (VPSPr; sporadic)
• Fatal insomnia (FI)
• Kuru

Is There a Cure for Prion Disease?

Prion disease is a contractible, incurable, degenerative disease. We have drugs to manage symptoms, but currently, nothing that can cure the condition.

However, there are some anti-prion drugs in the pipeline [6]:

1. Pentosan polysulfate — this is still being investigated, but there are already signs of limitation in humans.
2. Anle138b — although this is still undergoing research for its effects on prion disease in humans, it is showing promising results so far.
3. Astemizole — some research has shown that this compound can reduce the amount of prion protein produced by cells, thus slowing the disease progression [4].

CBD can slow the progression of the disease and increase the lifespan of those affected by about 6% [3].

Suggested Reading: Is CBD Oil Safe to Use With My Medication?

There’s Limited Evidence To Support The Effects of CBD For Prion Disease

There are almost no current studies specifically investigating the effects of CBD on prion disease. So far, we’ve only found one promising study on the connection between them.

The study in question involved giving CBD to mice infected with prion disease to see how it affected their lifespan. The mice given CBD in high doses — after being infected with prion disease — had a 6% delay in death from the condition compared with the control group [3].

Researchers in this study noted that CBD prevented the accumulation of a protein known as PrPres — the hallmark sign of prion disease. They concluded that CBD could be used to increase the survival of those affected with the disorder.

However, there were some problems with this study, as pointed out by another prominent researcher.

Issues With Prion Research

1. Timing of Treatment

The mice who showed improvement with CBD use were given high doses of CBD immediately following infection. This isn’t possible when prion disease in humans isn’t diagnosed until the late stages of the condition. By the usual stage of human diagnosis, CBD application is too late.

2. Mode of Prion Infection

Another problem with this study was how the mice were infected. In the study, they were injected with the disease. This changes how the infection works in the body.

Because this disease infects the brain, a prion circulating elsewhere in the body is considered pre-infectious and will behave differently than a prion infection within the brain. Prion research reports that the body develops specific antibodies to protect itself against prions that make their way into the bloodstream [5].

3. The dose of CBD Treatment

In this study, only mice receiving high doses of CBD showed any benefit.

The effective dose used in the study was 60 mg per kg for 12 weeks. This would equate to a dose of around 4800 mg for the average male user (80 kg).

That’s 240 mL of a 600 mg CBD oil — an unreasonable amount by all standards. That’s about eight standard 30 mL bottles of CBD oil per dose.

Even if you used a CBD isolate, you’d need at least 4800 mg to match the amount used in the study — which costs around $1300 per dose. You would need this dose every day for the rest of your life since there’s no cure for prion disease currently.

Final Verdict: Using CBD for Prion Disease

Unfortunately, prion disease remains a mystery, and there’s limited research on effective treatment options for the condition. There’s only one study to date highlighting the potential role CBD may play in the progression of the disease.

However, CBD can slow the progression of other non-prion protein folding diseases such as Alzheimer’s disease [9], Parkinson’s disease [10], and Huntington’s disease [11].

The benefits of CBD come from its protective role on the neurons, lowering neuroinflammation and oxidative damage — two of the primary causes of destruction resulting from prion disease.

CBD is also useful for managing many of the side-effects of prion diseases, including:

• Insomnia
• Anxiety
• Muscle stiffness
• Muscle tremors

The Future of Prion Disease: Where to Go from Here

Unfortunately, there isn’t much available research on the role of CBD or other cannabinoids for prion disease. The only study we have currently is an animal study using infected mice. The outcome of the study showed a 6% increase in lifespan among mice given high doses of CBD starting immediately after being injected with the prion [3].

The positive effects of CBD on other neurological diseases caused by misfolded proteins such Alzheimer’s disease, Huntington’s disease, and Parkinson’s disease also hint at a potential benefit from this important phytocannabinoid for prion diseases.

Recent advancements have allowed us to clone the gene responsible for manufacturing prions in mice — giving us the tools necessary to study the disease in more detail. Hopefully, there will be more research on the use of CBD for prion disease shortly.

References

1. Martín-Moreno, A. M., Reigada, D., Ramírez, B. G., Mechoulam, R., Innamorato, N., Cuadrado, A., & de Ceballos, M. L. (2011). Cannabidiol and other cannabinoids reduce microglial activation in vitro and in vivo: relevance to Alzheimers′ disease. Molecular pharmacology, mol-111.
2. García-Arencibia, M., González, S., de Lago, E., Ramos, J. A., Mechoulam, R., & Fernández-Ruiz, J. (2007). Evaluation of the neuroprotective effect of cannabinoids in a rat model of Parkinson’s disease: importance of antioxidant and cannabinoid receptor-independent properties. Brain research, 1134, 162-170.
3. Dirikoc, S., Priola, S. A., Marella, M., Zsürger, N., & Chabry, J. (2007). Nonpsychoactive cannabidiol prevents prion accumulation and protects neurons against prion toxicity. Journal of Neuroscience, 27(36), 9537-9544.
4. Karapetyan, Y. E., Sferrazza, G. F., Zhou, M., Ottenberg, G., Spicer, T., Chase, P., … & Lasmézas, C. I. (2013). Unique drug screening approach for prion diseases identifies tacrolimus and astemizole as antiprion agents. Proceedings of the National Academy of Sciences, 201303510.
5. White, A. R., Enever, P., Tayebi, M., Mushens, R., Linehan, J., Brandner, S., … & Hawke, S. (2003). Monoclonal antibodies inhibit prion replication and delay the development of prion disease. Nature, 422(6927), 80.
6. Trevitt, C. R., & Collinge, J. (2006). A systematic review of prion therapeutics in experimental models. Brain, 129(9), 2241-2265.
7. Sailer, A., Büeler, H., Fischer, M., Aguzzi, A., & Weissmann, C. (1994). No propagation of prions in mice devoid of PrP. Cell, 77(7), 967-968.
8. Langford, R. M., Mares, J., Novotna, A., Vachova, M., Novakova, I., Notcutt, W., & Ratcliffe, S. (2013). A double-blind, randomized, placebo-controlled, parallel-group study of THC/CBD oromucosal spray in combination with the existing treatment regimen, in the relief of central neuropathic pain in patients with multiple sclerosis. Journal of neurology, 260(4), 984-997.
9. Esposito, G., Scuderi, C., Valenza, M., Togna, G. I., Latina, V., De Filippis, D., … & Steardo, L. (2011). Cannabidiol reduces Aβ-induced neuroinflammation and promotes hippocampal neurogenesis through PPARγ involvement. PloS one, 6(12), e28668.
10. Chagas, M. H. N., Zuardi, A. W., Tumas, V., Pena-Pereira, M. A., Sobreira, E. T., Bergamaschi, M. M., … & Crippa, J. A. S. (2014). Effects of cannabidiol in the treatment of patients with Parkinson’s disease: an exploratory double-blind trial. Journal of Psychopharmacology, 28(11), 1088-1098.
11. Sagredo, O., Pazos, M. R., Satta, V., Ramos, J. A., Pertwee, R. G., & Fernández‐Ruiz, J. (2011). Neuroprotective effects of phytocannabinoid‐based medicines in experimental models of Huntington’s disease. Journal of neuroscience research, 89(9), 1509-1518.
12. Carter, G. T., Abood, M. E., Aggarwal, S. K., & Weiss, M. D. (2010). Cannabis and amyotrophic lateral sclerosis: hypothetical and practical applications, and a call for clinical trials. American Journal of Hospice and Palliative Medicine®, 27(5), 347-356.