Over on Face Book I have been sharing a “Fact a Day” as part of my efforts this month to raise awareness of Mitochondrial Disease, and wanted to share it here too. Here I can expound a little more on what each of these facts really mean to the average person. Feel free to share this information on your blog or Face Book too!!
1. Mitochondria exist in nearly every cell of the human body, producing 90% of the energy the body needs to function.
Air and food are metabolized by mitochondria. Every nucleated cell in the body contains from 5 to 2000 mitochondria. They are the size and shape of long, thread-like bacteria woven through our cells. Mitochondria consume over 80 percent of the oxygen we breathe and make over 90 percent of the energy our cells need to function. They use the oxygen in the air we breathe to release energy from food. This process transforms food calories into chemical energy, water, and carbon dioxide. The released chemical energy is then stored in the form of adenosine triphosphate (ATP). ATP is the universal currency of energy used by all life on earth. It is like an electrical power source that drives the engines of the cell. This process of burning food to make ATP is called oxidative phosphorylation. Only mitochondria can do it. Without it, muscles could not contract and neurons could not fire. Mitochondria literally make it possible for us to move and think.
Recent popular and scientific publications have focused on the "powerplant" functions of mitochondria. While it is true that energy production is one function of mitochondria, this is only a small part of what they do. Mitochondria in different tissues differ dramatically in their ability to consume oxygen and make ATP. For example, liver mitochondria consume just 2% of the oxygen that heart mitochondria do. Liver mitochondria are specialized for other duties. They contain, for examples, enzymes that allow them to detoxify ammonia, a waste product of protein metabolism. These enzymes are not made in the heart. Mitochondria also differ in the fuels they can bum. For example, mitochondria in the heart cannot use sugar for energy. They are entirely dependent on the metabolism of fats to meet their energy needs. In contrast, mitochondria in the liver can use both fats and sugars. The specialized functions of mitochondria help each tissue to perform its role in the day-to-day operation of the body. Children with mitochondrial disease have inherited specific mutations in either mitochondrial or nuclear genes (DNA). Their symptoms are a reflection of the tissues that need the function of that gene or genes most.
2. In a person with Mitochondrial Disease, the mitochondria are failing and cannot convert food & oxygen into life-sustaining energy.
This whole process of taking food and oxygen and converting it to the chemical the cells use for energy gets interrupted. There are road blocks, if you will, and when all is said and done, not enough energy is able to be produced to run the systems in the body that need it. And lets face it, every system in the body needs energy to work right. The result is anything from a “brown out” to a “black out” in the systems involved, making sustaining life difficult if not impossible.
3. For many, Mitochondrial Disease is an inherited genetic condition, while for others the body’s mitochondria can be affected by other environmental factors.
There are numerous ways one can end up with mitochondrial disease. Mitochondria were at one time an individual organism that became symbiotic with the human body. Because of this, mitochondria have their own DNA called mitochondrial DNA or mtDNA. This DNA is only passed on through the mother, but is passed on 100% of the time. This is useful in the arena of tracing remains back through the maternal line as they have done in the case of some of the pharaoh’s, but brings with it issues if there are defective mitochondria being passed on. There was a time when it was thought that all, or at least most, mitochondrial diseases were maternally inherited, however that has changed as more is understood about this disease.
The other way to pass this disease on is through the nuclear DNA or nDNA. It turns out that the replication of the mitochondrial DNA is significantly impacted by certain nDNA that play a part in the process. So as new mitochondria are formed, these nDNA must do their part or defects arise in the mtDNA. In this case, Mendelian inheritance patterns exist, which is the more traditional way to inherit from the parents.
It is now thought that anywhere from 80-90% of mitochondrial disease is from the nDNA, with 10-20% being maternally inherited.
Finally, both medications and other disease processes can cause mitochondrial dysfunction.
4. The parts of the body that need the most energy, such as the heart, brain, muscles and lungs, are the most affected by mitochondrial disease. The affected individual may have strokes, seizures, gastro-intestinal problems, (reflux, sever vomiting, constipation, diarrhea), swallowing difficulties, failure to thrive, blindness, deafness, heart and kidney problems, muscle failure, heat/cold intolerance, diabetes, lactic acidosis, immune system problems and liver disease.
5. Affected individuals may have seizures, severe vomiting, failure to thrive, heat/cold intolerance, poor muscle tone, delayed achievement of milestones, severe diarrhea/constipation, feeding problems, unable to fight typical childhood infections or repeated infections and fevers without a known origin.
6. A "red flag" for mitochondrial disease is when a child or adult has more than 3 organ systems with problems or when a "typical" disease exhibits atypical qualities.
If a child is stricken with a catastrophic disease affecting three or more organ systems, or if a child has been afflicted with a relapsing disease that affects two or more organ systems and leads to slow but measurable deterioration, he or she may have a mitochondrial disease. At times, mitochondrial diseases can cause isolated symptoms. These may include unexplained seizures, low blood counts, dystonia (abnormal muscle tone or spasms), blindness, deafness, dementia, ataxia (stumbling or tremors), cerebral palsy, heart failure, or progressive muscle weakness. More often, however, several organ systems are affected in sequence, one faltering or failing after another. Good periods are frequently punctuated by abrupt deteriorations that are caused by simple infections. For children with mitochondrial disease these infections can be life threatening, and leave them with deficits that cannot be recovered.
7. As more research dollars are raised to find more effective treatments and ultimately a cure, some of the affected children and adults are living fairly normal lives with mitochondrial disease. At the opposite end of the spectrum, many are severely affected, and some children do not survive their teenage years.
The only treatment that exists at this time is essentially treating each system that is affected and hoping that you can reduce the stress on that system enough to not cause issues with other systems. In other words, it’s a game of trying to catch new issues or continuing issues as quickly as possible and put those fires out as best you can. It’s a never-ending battle, and one that so often is impossible to keep up with. Just as you see some stability, something new rocks the apple cart and your back at square one.
However, and this is where awareness comes in, the more doctors that know and understand the intricacies of this disease, and thus react more quickly and proactively to new issues, the better these kids are doing. Understanding and knowledge is the key to some stability……funding and research are the keys to actually improving quality of life!!