Overview

Study the impact of mitochondrial changes on the process of aging.

Introduction

Mitochondria are known as the powerhouses of cells due to their role in generating ATP through oxidative phosphorylation. However, given time, mitochondrial function tends to decline, which has been linked to the aging process and various age-related diseases. Such a phenomenon is be called “mitochondrial dysfunction”.

Mitochondrial dysfunction is identified by a reduction in the ability in the electron transport chain and reductions in the synthesis of high-energy molecules and is a cause of aging, and essentially, of all chronic neurological diseases.

Main reasons for mitochondrial dysfunctions in aging

·        Mitochondrial DNA Mutations

Mitochondrial DNA (mtDNA) mutations refer to changes in the genetic material either as a result of errors in DNA replication or from the harmful effect of mutagens such as chemicals that change the individual structures of nucleotides making up our DNA found in the mitochondria. This can lead to defective or incomplete proteins, disrupting the electron transport chain (ETC) and ATP synthesis. Furthermore, defective components of the ETC can cause electrons to leak and react with oxygen, forming ROS. High levels of ROS can further damage mtDNA, lipids and proteins. This can also cause metabolic imbalance and cause cell death.

·        Mitochondrial Biogenesis

Mitochondrial biogenesis is the process by which cells increase their mitochondrial mass and number to replace damaged mitochondria or to meet increased energy demands. Although this process is beneficial, when disrupted it can cause further mutations, imbalanced biogenesis without the removal of defective and unwanted mitochondria causing the assembling of defective mitochondria (Mitophagy).

·        Oxidative stress

Oxidative stress is a condition caused by an imbalance between the production of reactive oxygen species (ROS) and the body’s ability to neutralize and detoxify these harmful byproducts using antioxidants. This imbalance contributes to different types of diseases and aging processes. Oxidative stress can lead to mitochondrial dysfunction through direct damage to mitochondrial elements, disruption of mitochondrial functions, disablement of the mitochondrial DNA, and interference with key mitochondrial processes. Environmental factors also play a role in such a dysfunction.

Diseases caused by mitochondrial dysfunction

·        Neurogenerative diseases such as Alzheimer’s and Parkinson’s diseases

·        Cardiovascular diseases which include heart failure

·        Metabolic disorders including obesity and diabetes mellitus

·        Cancers due to genetic instability

·        Disorders such as autism spectrum disorder and Leigh syndrome

Ways to reduce mitochondrial dysfunction

Although this dysfunction cannot be cured, steps can be taken to prevent it and mitigate its effects. Such steps include:

·        Supportive therapy which includes exercising, taking multivitamins and amino acid supplements

·        Taking medications and antioxidants to reduce further symptoms

·        Physical therapy

·        Gene therapy which targets central genetic defects that cause mitochondrial diseases. However, gene therapy for mitochondrial dysfunctions is still in its early stages.

Conclusion

Although more research is required for mitochondrial dysfunction and aging, many core concepts of ways in which human lifespan can be altered and increased can be achieved from it. Furthermore, many diseases related with aging and growing old may be related to this dysfunction.

Written by: Ammiyla Sarwar

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