Amyloids are small clumps of protein fibers that gather around various cells in the human body. These clumps have links to many conditions, including neurodegenerative diseases like Alzheimer’s and localized issues like carpal tunnel syndrome.

Though the discovery of amyloids happened hundreds of years ago, much remains unknown about these unique protein aggregates. As research continues, it is possible that uncovering the secrets behind amyloids could lead to significant advancements in managing several serious diseases.

Amyloid Structure

An amyloid is not a specific protein. Instead, each amyloid consists of a wide variety of proteins that have misfolded. Misfolding is a process in which a previously healthy protein loses both its structure and physiological functions. The remains of the proteins form fiber-like clumps that collect around nerve cells.

Each amyloid resembles a series of fibers that are between seven and 13 nanometers wide and a few micrometers in length.


Alzheimer's disease: the amyloid-beta peptide accumulates to amyloid fibrils that build up dense amyloid plaques. selvanegra/ Getty Images


The Proteins That Form Amyloids

To date, researchers have identified around 40 human proteins that form amyloids and have connections to specific diseases. Experts hope that by discovering which proteins become amyloids, they will be able to better predict the effects the process has on human health.

Many of the proteins that can be affected in this way are not recognized outside of the medical community, but a few are well-known, including insulin and prolactin.


The molecular structure of the ß-amyloid-peptide. The amyolid-peptide aggregates on axons of neuons building amyloid plaques selvanegra/ Getty Images


How Amyloids Form

An amyloid forms once hundreds to thousands of proteins or peptides fuse into long fibers. This takes place in three stages: a nucleation phase, a growth phase, and a plateau phase.

In recent years, researchers have found that the formation process of each amyloid can be quite different, depending on which secondary forces intervene in the process.


Amyloid plaques are misfolded proteins aggregates beetween neurons, Alzheimer's disease illustration Artur Plawgo/ Getty Images


Amyloid Role in Disease

Researchers are not sure why amyloids cause disease. Some studies have found that amyloid deposits directly interfere with tissues, disrupting their functions. In other instances, amyloids seem to be toxic to neurons. Experts also believe that some amyloids cause calcium dysregulation and mitochondrial dysfunction.

These various forms of toxicity all result in cell death, either directly or by speeding up the normal process of apoptosis.  

Deoxyribonucleic acid (DNA) (deoxyribonucleic acid) damage, illustration. KATERYNA KON/SCIENCE PHOTO LIBRARY/ Getty Images


Accumulations of Amyloids

Rather than a specific disease, build-ups of amyloids can cause many different conditions. The term amyloidosis refers to these rare but serious issues. Amyloidosis has many classifications, each stemming from the original protein that formed the responsible amyloid.

For example, if immunoglobulin light chains cause amyloidosis, it gains the term “AL.” Historically, researchers believed that AL was the most common form of amyloidosis and that it was extremely rare in the general population. However, modern studies show that another type called ATTR is the most widespread amyloidosis, and experts no longer consider it a rare disease.  

Amyloidosis - blood disorder abstract. Hailshadow/ Getty Images


Symptoms of Amyloidosis

Amyloidosis has a broad presentation, and symptoms usually depend on the area where amyloids are gathering, as well as the responsible protein. The most common accumulation sites are the heart and the kidneys.

Amyloidosis of the kidneys is usually AL or AA amyloidosis and can cause nephrotic syndrome and kidney failure. Amyloidosis of the heart can cause heart failure and its related symptoms, including shortness of breath, edema, and fatigue.  

A hurting woman, who is sitting on a couch and holding her lower back with her left hand. Povozniuk/ Getty Images


Major Conditions With Links to Amyloidosis

Because of the widespread nature of amyloids, many conditions connect to amyloidosis. Currently, experts have identified several major conditions with links to amyloidosis, though they are not able to fully understand the connections. These issues include

  • Alzheimer’s disease due to amyloidosis of the nervous system
  • Carpal tunnel syndrome due to amyloidosis of the musculoskeletal system
  • Diabetes due to amyloidosis of the pancreas
  • Sleep apnea due to amyloidosis of the tongue

 businesswoman hurt with carpal tunnel syndrome disability. Feeling discomfort cramp in arm and hand PeopleImages/ Getty Images


Diagnosing Amyloid Issues

Doctors have several ways of diagnosing amyloidosis or locating amyloids. The first is a tissue biopsy. Amyloids absorb many dyes, so by staining the tissue sample, experts can see amyloids with a microscope. In some cases, the tissue sample comes from the affected organ, but it may also originate from the subcutaneous abdominal fat.  

A senior woman sit up on the exam table as she talks with her male doctor FatCamera/ Getty Images


Treating Amyloid Issues

Currently, treatment depends on the type of amyloidosis. Because AL and ATTR stand out as the most common types, there has been more research into their treatments. For AL amyloidosis, chemotherapy and then stem cell transplantation shows promise in early studies.

Historically, ATTR amyloidosis required a kidney transplant, but that is no longer the only effective choice. Managing ATTR amyloidosis now focuses on preventing the destabilization of healthy proteins and using anti-inflammatory drugs.


Shot of a mature doctor having a consultation with his patient Jay Yuno/ Getty Images


Ongoing Amyloid Research

Because so much remains unknown about amyloids, researchers are casting a wide net and performing many different studies with a variety of purposes. Many people feel that previous research improperly painted amyloids as purely negative while ignoring their potential benefits.

Recent studies show that amyloids have powerful antioxidant and antibacterial effects, earning these ones the name “functional amyloids.” These functional amyloids could boost immune function, among other benefits like encouraging hormone production and reducing the degradation of RNA.  

Medical Science Laboratory: Beautiful Scientist Looking Under Microscope Does Analysis of Test Sample. gorodenkoff/ Getty Images


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