Mitochondria: the energy of life

The mitochondria is the powerhouse of the cell. But why is it unique and how can you protect the mitrochondria in small animals?

Mitochondria are fascinating and critically important “powerhouse” organelles inside cells. They use oxygen to make energy in the form of ATP. Mitochondria are unique in that their ancestors are bacteria that were ingested into cells to form a beneficial host/bacteria relationship (termed endosymbiosis) over 1.45 billion years ago. Thus, each of our cells has two different sets of DNA — one in the host cell nucleus, and the second in mitochondria (MtDNA). However, only maternal MtDNA is inherited.

During normal metabolism, mitochondria generate harmful reactive oxygen species (ROS) that must be neutralized and balanced by antioxidants to prevent cellular damage. In fact, mitochondria can inflict self-injury as they are the main intracellular generators of ROS as well as the main target of ROS attack. An imbalance of ROS and antioxidants can cause mitochondrial dysfunction, leading to inflammation and chronic illness. When antioxidant defenses are inadequate to neutralize ROS, cell damage and/or cell death results, initiating inflammation. Neutralization of ROS occurs by a variety of antioxidant systems, including the glutathione redox system, ascorbic acid, tocopherals, retinoids, catalase and superoxide dismutase.

Mitochondrial disease is a group of disorders characterized by dysfunctional energy production (ATP) along the mitochondrial electron transport chain. Most disease processes have some degree of mitochondrial dysfunction. Mitochondrial damage can occur from either too little or too much energy production. Because cells of the eye, brain and muscles require a lot of energy, they have particularly high densities of mitochondria. When mitochondria are not healthy, these tissues are often the first to show signs of poor function. Mitochondrial dysfunction can have primary (genetic) or secondary (e.g. age-related, infectious) causes. Aging tissues undergo oxidative stress because their mitochondria often fail to produce sufficient ATP. Since eyes are continually bombarded with oxidative stressors (UV light and oxygen), and mitochondria both generate and can be damaged by oxidative stress, it makes sense that chronic exposure to oxidative stress causes instability and cumulative damage of mitochondrial DNA.

Glaucoma causes chronic hypoperfusion of the optic nerve. Because the optic nerve contains abundant mitochondria, this makes it vulnerable to damage from glaucoma. Cancer is also associated with mitochondrial dysfunction. Mitochondria play important roles in carcinogenesis by altering energy metabolism, resisting apoptosis, increasing ROS production, and altering mtDNA. Uveal melanoma is the most common primary intraocular tumor in dogs, cats and humans. Novel therapies for this cancer are directed at inhibiting tumor-specific mitochondrial function, and hold promise as a new way to treat ocular cancers.

Supplements that reduce mitochondrial dysfunction help maintain healthy glutathione levels and include vitamins C and E (in the form of mixed tocopherals), alpha lipoic acid, coenzyme Q10, folate, vitamins B6 and B12, green tea extract, turmeric, Omega-3 fatty acids and zinc.

Providing a variety of antioxidants to dogs and cats may better protect the powerhouse of their cells from constant attack and self-combustion by ROS. The foundation of health is protection and enhancement of the energy of life.