Background: Mitochondria
Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called Adenosine TriPhosphate (ATP). Mitochondria contain their own small chromosomes and generally we only inherit Mitochondrial DNA (mtDNA) from the mother. Nuclear DNA is inherited from both parents. In all mammals this is generally the case.
Mitichondria has a peculiar arrangement with two different membranes - inner & outer - quite unusual for an intercellular organelle. These membranes function in the purpose of mitochondria, which is essentially to produce energy.
These capsule-shaped organelles generate more than 90 percent of our energy, which is why they’re often called “the powerhouse of the cell.”
Different cells have different amounts of mitochondria because they need more energy. So for example, the muscle has a lot of mitochondria, the liver does too, the kidney as well, and to a certain extent, the brain, which lives off of the energy those mitochondria produce. So if you have a defect in the pathways that the mitochondria usually functions with, you're going to have symptoms in the muscle, in the brain, sometimes in the kidneys as well; many different types of symptoms. And we probably don't know all of the different diseases that mitochondrial dysfunction causes.
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Researchers from Amsterdam UMC and Vrije Universiteit Amsterdam (VU) have discovered that the persistent fatigue in patients with long-COVID has a biological cause, namely mitochondria in muscle cells that produce less energy than in healthy patients.
"We saw various abnormalities in the muscle tissue of the patients. At the cellular level, we saw that the mitochondria of the muscle, also known as the energy factories of the cell, function less well and that they produce less energy," says Rob Wüst, Assistant Professor at Department of Human Movement Sciences at the VU University. "So, the cause of the fatigue is really biological. The brain needs energy to think. Muscles need energy to move. This discovery means we can now start to research an appropriate treatment for those with long-COVID," adds van Vugt.
One of the theories about long-COVID is that coronavirus particles may remain in the body of people who have had the coronavirus. "We don't see any indications of this in the muscles at the moment," says Van Vugt. The researchers also saw that the heart and lungs functioned well in the patients. This means that the long-lasting effect on patient's fitness is not caused by abnormalities in the heart or lungs.
Exercising is not always good for patients with long-COVID. "In concrete terms, we advise these patients to guard their physical limits and not to exceed them. Think of light exertion that does not lead to worsening of the complaints. Walking is good, or riding an electric bike, to maintain some physical condition. Keep in mind that every patient has a different limit," says Brent Appelman, researcher at Amsterdam UMC. "Because symptoms can worsen after physical exertion, some classic forms of rehabilitation and physiotherapy are counterproductive for the recovery of these patients," van Vugt adds.
Although the majority of people infected with the SARS-CoV-2 virus recover within weeks, a subgroup, estimated to be around one in eight, will get long-COVID. Symptoms in patients with long-COVID, post-acute sequelae or COVID or post-COVID syndrome (PCS) include severe cognitive problems (brain fog), fatigue, exercise intolerance, autonomic dysregulation, postural orthostatic tachycardia syndrome (POTS), orthostatic intolerance, and worsening of symptoms after PEM. (Post-Exertional Malaise)
PS: This is a peer reviewed study. But I have read previously - in early 2023 - researchers from Taiwan and also in the UK making the same claim. Both these teams reported independently that it's Mitochondrial dysfunction which is the root cause of Long-Covid fatigue.
Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called Adenosine TriPhosphate (ATP). Mitochondria contain their own small chromosomes and generally we only inherit Mitochondrial DNA (mtDNA) from the mother. Nuclear DNA is inherited from both parents. In all mammals this is generally the case.
Mitichondria has a peculiar arrangement with two different membranes - inner & outer - quite unusual for an intercellular organelle. These membranes function in the purpose of mitochondria, which is essentially to produce energy.
These capsule-shaped organelles generate more than 90 percent of our energy, which is why they’re often called “the powerhouse of the cell.”
Different cells have different amounts of mitochondria because they need more energy. So for example, the muscle has a lot of mitochondria, the liver does too, the kidney as well, and to a certain extent, the brain, which lives off of the energy those mitochondria produce. So if you have a defect in the pathways that the mitochondria usually functions with, you're going to have symptoms in the muscle, in the brain, sometimes in the kidneys as well; many different types of symptoms. And we probably don't know all of the different diseases that mitochondrial dysfunction causes.
---------------------------------------------------------------------------------------------------------------------------------------------------------
Back to the topic -
Researchers from Amsterdam UMC and Vrije Universiteit Amsterdam (VU) have discovered that the persistent fatigue in patients with long-COVID has a biological cause, namely mitochondria in muscle cells that produce less energy than in healthy patients.
"We saw various abnormalities in the muscle tissue of the patients. At the cellular level, we saw that the mitochondria of the muscle, also known as the energy factories of the cell, function less well and that they produce less energy," says Rob Wüst, Assistant Professor at Department of Human Movement Sciences at the VU University. "So, the cause of the fatigue is really biological. The brain needs energy to think. Muscles need energy to move. This discovery means we can now start to research an appropriate treatment for those with long-COVID," adds van Vugt.
One of the theories about long-COVID is that coronavirus particles may remain in the body of people who have had the coronavirus. "We don't see any indications of this in the muscles at the moment," says Van Vugt. The researchers also saw that the heart and lungs functioned well in the patients. This means that the long-lasting effect on patient's fitness is not caused by abnormalities in the heart or lungs.
Exercising is not always good for patients with long-COVID. "In concrete terms, we advise these patients to guard their physical limits and not to exceed them. Think of light exertion that does not lead to worsening of the complaints. Walking is good, or riding an electric bike, to maintain some physical condition. Keep in mind that every patient has a different limit," says Brent Appelman, researcher at Amsterdam UMC. "Because symptoms can worsen after physical exertion, some classic forms of rehabilitation and physiotherapy are counterproductive for the recovery of these patients," van Vugt adds.
Although the majority of people infected with the SARS-CoV-2 virus recover within weeks, a subgroup, estimated to be around one in eight, will get long-COVID. Symptoms in patients with long-COVID, post-acute sequelae or COVID or post-COVID syndrome (PCS) include severe cognitive problems (brain fog), fatigue, exercise intolerance, autonomic dysregulation, postural orthostatic tachycardia syndrome (POTS), orthostatic intolerance, and worsening of symptoms after PEM. (Post-Exertional Malaise)
PS: This is a peer reviewed study. But I have read previously - in early 2023 - researchers from Taiwan and also in the UK making the same claim. Both these teams reported independently that it's Mitochondrial dysfunction which is the root cause of Long-Covid fatigue.
