Science has a good understanding of the role of mitochondria as the central powerhouses of human cells, but what role do the play in ageing? Is mitochondrial dysfunction a risk factor for neurodegenerative disorders and the overall health of the human brain?.

Is there a Link Between Mitochondrial Dysfunction and Neurological Disorders?

As previously mentioned mitochondria are mostly responsible for processing food, combining it with oxygen, to generate energy known as adenosine triphosphate (ATP). Thus, mitochondria are vitally responsible for providing the body’s energy. Disturbances to the process of mitochondria-provided energy result in altered innate function and have been identified as a critical area in the pathogenesis of many human diseases. Neurological conditions are not immune to this. As mitochondria are critical regulators of cell death, reduced mitochondrial health and function has a key role in neurodegeneration. Ageing is also a significant risk factor in neurodegenerative diseases, and mutations in mitochondrial DNA and oxidative stress contribute to ageing.

What Changes can Mitochondrial Dysfunction Induce in the Human Body?

Mitochondrial dysfunction is a wide-ranging term explaining many cellular reactions caused by disturbed energy output. Changes that can occur due to disturbed mitochondrial health include:

• reduced energy production
• increased production of reduced oxygen species and therefore free radicals
• altered gene signalling and
• less control over the quality of a cell

Neurons have a vital requirement for mitochondria to supply ATP and a higher demand for oxygen, which means they are more susceptible to damage if the mitochondria are not functioning optimally. If neurons have lower levels of antioxidant defences, they are exposed to an increased level of free radical damage.

Mitochondria and Depression

There is evidence to suggest mitochondrial dysfunction is associated with depression due to new insights that the pathophysiology of depression may be linked to neuroplasticity and cellular resistance. Mitochondria’s part in ATP production and cell signalling mean they have a permanent role in membrane stability, reactive oxygen species balance and to execute the complex processes of neurotransmission. These are all things that are now identified as contributors to the pathogenesis of depression. Enhancing mitochondrial function appears to be a reasonable strategy for the treatment of neuronal function and, therefore, the management of mood disorders. This treatment may target specific mechanisms of mitochondrial dysfunction such as energy metabolism, synaptic plasticity and the survival of neurons.

Mitochondrial Dysfunction and Parkinson’s Disease

Parkinson’s disease (PD) is a disorder also associated with intellectual disabilities such as cognitive impairment. Like depression, dysfunctional mitochondria have a significant role in the pathophysiology of PD due to mutations of the mitochondrial genes and oxidative stress. Since normal functioning of the mitochondria is essential for the energy requirements and cognitive processes in the brain, the underlying factors that can aggravate the function of mitochondria can, therefore, influence neurodegenerative processes and PD. Preclinical studies in different animal models have proven the involvement of mitochondria in disease pathology and conclude that mitochondrial dysfunction is one of the underlying contributors to the cognitive impairment process in PD.