Every human cell has many mitochondria inside the cytoplasm. These organelles play a crucial role because they are responsible for energy production that drives all of the processes in the cell. Diseases of the mitochondria are devastating and dysfunction of the mitochondria is believed to play an important role in aging. For our purposes, think of the mitochondria as a windmill. When the wind turns the blades on the wheel, energy is produced. In windmills, that energy can be used for many purposes including grinding grain, generating electricity and more. In the cell, the mitochondrial energy is used to support almost all cell functions though a very intricate process.

Function of Mitochondria

The mitochondria produce energy by converting ADP to ATP. During the process of forming ATP (which is called oxidative phosphorylation), the mitochondria uses oxygen as a carrier for electrons. To use the windmill analogy, the ADP/ATP forms the blades of the windmill, while electrons turn the windmill’s blades. Once the electrons have done their work of spinning the blades (converting ADP to ATP), the energy is stored as ATP. The electrons are then bound to oxygen and carried off (usually as water). The bottom line is that mitochondria use the flow of electrons to generate energy that is stored in ATP. Oxygen is consumed in this process. This complicated process occurs in the intricate membranes of the mitochondria.

Why are mitochondria thought to play a role in aging?

The process of energy production in the mitochondria results in excess electrons, many of which are bound to oxygen to form water. When the electrons are bound to oxygen in even numbers they are harmless. However, some of the electrons slip out and bind singly to oxygen, leading to a superoxide, which is also known as a free radical. (When 4 electrons bind to oxygen, water is formed. If only one electron binds, then a free radical is formed.) These free radicals cause damage to the mitochondrial membranes and mitochondrial DNA, and have a harmful effect on LDL cholesterol, which is a component of cell membranes.

Why free radicals are harmful to the skin?

Free radicals have an uneven number of electrons. This makes them unstable. They will steal electrons from other cellular components to give themselves an even number of electrons. It is the instability of the odd number of electrons that makes free radicals harmful. Free radicals will steal electrons from DNA, lipids in cell membranes (such as LDL), proteins, and other vital structures, which in turn leaves them damaged. Antioxidants give the free radicals the electron they crave, neutralizing them so that they will not do damage.

Mitochondrial DNA

In science class, I am sure you learned about genetics and the DNA contained in the chromosomes of the nucleus. Well, it turns out that mitochondria have their own DNA. The mitochondrial DNA contains the code needed to make the proteins that are in the membranes of the mitochondria. These proteins are necessary for energy production. The mitochondrial DNA is different than nuclear DNA. In other words, the coding for these mitochondrial proteins is not found in the nucleus and cannot occur without the mitochondria’s contribution. For this reason, we are dependent on the proper coding of the mitochondrial DNA for energy production. Mitochondrial DNA is endlessly fascinating, but I will focus on two aspects of it:

1. When free radicals damage the mitochondrial DNA, this leads to an excess build-up of electrons, which may accelerate aging. These electrons likely accelerate aging by forming even more free radicals or by causing damage on their own. The impact of the damage that the electrons cause is just beginning to be discovered. I expect advances in this area of research in the near future. Dr. de Grey’s book has a great discussion on this in Chapter 6.

2. The DNA in the mitochondria is inherited differently than the nuclear DNA. It all comes from the mother! This fact has opened a new door in genetic research and allowed scientists to trace species back through their maternal lineage. It is highly likely that mitochondrial dysfunction passed from the mother could impact skin aging, but the research has ways to go before this is understood.

Mitochondria in Skin Appearance

For the last five to eight years, dermatologists who perform many light and laser procedures have begun to suspect that certain wavelengths of light may have effects on the skin that go beyond what is currently understood. Skin appearance is improved in a way that is poorly explained by the currently accepted mechanisms of action associated with lasers and light emitting diodes (LEDs). Scientists have begun to suspect that the light has effects on mitochondria. Certain wavelengths may stimulate mitochondria to work better. However, studies are demonstrating that sun exposure (ultraviolet light) may have harmful effects on mitochondria. The role of mitochondria, lasers, and lights in skin appearance is being studied and hopefully will have breakthroughs soon.

What to do about it

Right now, all you can do to protect your mitochondria is eat antioxidants and avoid sun exposure—and hope that your mother gave you some good mitochondrial genes. Support foundations that research mitochondrial diseases and keep current with your science. It is my hope that when the scientific breakthroughs occur, that you will be able to understand them based on your knowledge of mitochondrial function. Keep following Skin Type Solutions and I will keep you up to date on the findings as they occur.

We hope that you enjoyed the sixth installment in our series about “The 7 causes of Aging.” One more to go! I hope you are feeling as enlightened as I am! Stay tuned for next week when we’ll discuss our last topic “Mutations in the nucleus” as a cause of aging.