Is M.E. an acquired form of Mitochondrial Myopathy?

[Sly Saint]

What are the symptoms of mitochondrial myopathy?

Myopathy
The main symptoms of mitochondrial myopathy are muscle fatigue, weakness, and exercise intolerance. The severity of any of these symptoms varies greatly from one person to the next, even in the same family.

In some individuals, weakness is most prominent in muscles that control movements of the eyes and eyelids. Two common consequences are the gradual paralysis of eye movements, called progressive external ophthalmoplegia (PEO), and drooping of the upper eyelids, called ptosis. Often, people automatically compensate for PEO by moving their head to look in different directions, and might not notice any visual problems. Ptosis can impair vision and cause a listless expression, but can be corrected by surgery.

Mitochondrial myopathies also can cause weakness and wasting in other muscles of the face and neck, which can lead to difficulty with swallowing and, more rarely, slurred speech. People with mitochondrial myopathies also may experience muscle weakness in their arms and legs.

Exercise intolerance, also called exertional fatigue, refers to unusual feelings of exhaustion brought on by physical exertion. The degree of exercise intolerance varies greatly among individuals. Some people might have trouble only with athletic activities like jogging, while others might experience problems with everyday activities such as walking to the mailbox or lifting a milk carton.

Sometimes, mitochondrial disease is associated with muscle cramps. In rare instances it can lead to muscle breakdown and pain after exercise. This breakdown causes leakage of a protein called myoglobin from the muscles into the urine (myoglobinuria). Cramps or myoglobinuria usually occur when someone with exercise intolerance “overdoes it,” and can happen during the overexertion or several hours afterward.

While overexertion should be avoided, moderate exercise appears to help people with mitochondrial myopathy maintain strength.

Encephalomyopathy
A mitochondrial encephalomyopathy typically includes some of the symptoms of myopathy plus one or more neurological symptoms. Again, these symptoms vary greatly among individuals in both type and severity.

In addition to affecting eye muscles, a mitochondrial encephalomyopathy can affect the eye itself and parts of the brain involved in vision. For instance, vision loss, due to optic atrophy (shrinkage of the optic nerve) or retinopathy (degeneration of some of the cells that line the back of the eye), is a common symptom of mitochondrial encephalomyopathy.

Sensorineural hearing loss is a common symptom of mitochondrial diseases. It is caused by damage to the inner ear (the cochlea) or to the auditory nerve, which connects the inner ear to the brain. Sensorineural hearing loss is permanent but it can be managed through alternative forms of communication, hearing aids, or cochlear implants. Hearing aids amplify sounds before they reach the inner ear. Cochlear implants bypass damaged parts of the inner ear and stimulate the auditory nerve.

Mitochondrial diseases can cause ataxia, which refers to trouble with balance and coordination. People with ataxia are prone to falls, and may need to use supportive aids such as railings, a walker, or a wheelchair. Physical and occupational therapy also may help.

Other common symptoms of mitochondrial encephalomyopathy include migraine headaches and seizures. There are many effective medications for treating and helping to prevent migraines and seizures, including anticonvulsants and other drugs developed to treat epilepsy.

https://www.ninds.nih.gov/Disorders...Fact-Sheets/Mitochondrial-Myopathy-Fact-Sheet

 

[Trish]

The mitochodrial myopathies and encephalopathies described in this document are all inherited genetic defects in mitochondrial or nuclear DNA, and most if not all show up in infancy to early adulthood.

There are some overlaps in symptoms with ME, but some significant differences too. I don't think anyone knows what ME is yet.

 

[Sly Saint]

from same article:

What are mitochondrial myopathies?
Mitochondrial diseases are caused by defects in mitochondria, which are energy factories found inside almost all the cells in the body. Mitochondrial diseases that cause prominent muscular problems are called mitochondrial myopathies (myomeans muscle and pathos means disease), while mitochondrial diseases that causes both prominent muscular and neurological problems are called mitochondrial encephalomyopathies (encephalo refers to the brain).

A typical human cell relies on hundreds of mitochondria to meet its energy needs. The symptoms of mitochondrial disease vary, because a person can have a unique mixture of healthy and defective mitochondria, with a unique distribution in the body. In most cases, mitochondrial disease is a multisystem disorder affecting more than one type of cell, tissue, or organ.

Because muscle and nerve cells have especially high energy needs, muscular and neurological problems are common features of mitochondrial disease. Other frequent complications include impaired vision, cardiac arrhythmia (abnormal heartbeat), diabetes, and stunted growth. Usually, a person with a mitochondrial disease has two or more of these conditions, some of which occur together so regularly that they are grouped into syndromes.

What causes mitochondrial myopathies?
Mitochondrial diseases are caused by genetic mutations. Genes provide the instructions for making proteins, and the genes involved in mitochondrial disease normally make proteins that work inside mitochondria. Within each mitochondrion, these proteins make up part of an assembly line that uses fuel molecules (sugars and fats) derived from food combined with oxygen to manufacture the energy molecule adenosine triphosphate, or ATP.

Proteins at the beginning of the assembly line import sugars and fats into the mitochondrion and then break them down to provide energy. Proteins toward the end of the line—organized into five groups called complexes I, II, III, IV, and V—harness that energy to make ATP. This highly efficient part of the ATP manufacturing process requires oxygen, and is called the respiratory chain. Some mitochondrial diseases are named for the part of the respiratory chain that is affected, such as complex I deficiency.

A cell filled with defective mitochondria becomes deprived of ATP and can accumulate a backlog of unused fuel molecules and destructive forms of oxygen called free radicals or reactive oxygen species. These are the targets of antioxidant compounds (found in many foods and nutritional supplements) that appear to offer general defenses against aging and disease.

In such cases, excess fuel molecules are used to make ATP by inefficient means, which can generate potentially harmful byproducts such as lactic acid. (This also occurs when a cell has an inadequate oxygen supply, which can happen to muscle cells during strenuous exercise.) The buildup of lactic acid in the blood—called lactic acidosis—is associated with muscle fatigue, and might damage muscle and nerve tissue.

Muscle and nerve cells use the ATP derived from mitochondria as their main source of energy. The combined effects of energy deprivation and toxin accumulation in these cells can lead to many muscular and neurological symptoms.

 

[wigglethemouse]

After Paul Fishers video and paper I found this NIH site on Mitochondrial complex V deficiency interesting
https://ghr.nlm.nih.gov/condition/mitochondrial-complex-v-deficiency

Mitochondrial complex V deficiency can cause a wide variety of signs and symptoms affecting many organs and systems of the body, particularly the nervous system and the heart.

Another common feature of mitochondrial complex V deficiency is hypertrophic cardiomyopathy. This condition is characterized by thickening (hypertrophy) of the heart (cardiac) muscle that can lead to heart failure.

If I remember right haven't there been some studies showing thickening of the heart wall in ME?

 

[Sly Saint]