Investigating Alzheimer's Disease: what remains the underlying cause of one of the deadliest diseases in the world today?

By: Mrunal Bagal

Alzheimer’s disease remains one of the deadliest diseases, affecting around 6 million Americans. The numbers are predicted to go up to 14 million by 2050. One of the main causes of AD is neural deterioration, which leads to a loss of neurons as one ages. This can result in impaired memory, concentration and attention for most of the patients. There are several factors that can lead to neurons deteriorating, such as the environment, family history and genetics.

Previous research has identified several genes playing a critical role in genetic pathways inside the human body and eventually causing AD. A genetic pathway is a sequence of genes that work together to perform a specific biological function in the body. One of the major pathways that is affected during AD is called the Aβ (amyloid-beta) pathway. Amyloid-beta is a protein produced from the genes inside the pathway. During AD, amyloid-beta is produced irregularly, resulting in the formation of their plaques around the brain. If these plaques accumulate for a long period of time, they can cause neuron damage and eventually deterioration. Additionally, the synaptic vesicle pathway is another pathway researched to be involved in the AD. This pathway mainly controls neurotransmission and vesicle fusion/recycling. Several genes work together to promote vesicle fusion (vesicle contains neurotransmitters inside it) and eventually release neurotransmitters. Research shows that this pathway may be affected in patients with AD, as several genes, such as SYT1, SNAP25 and STXBP1 have been linked to being highly expressed inside the pathway. Consequently, these genes could be leading to excessive neurotransmitter release, which may potentially be causing neuron damage/deterioration.

In addition to genetics, researchers have also investigated environmental factors, such as air pollution, affecting patients with Alzheimer’s. The causes are still not well researched, but a long-term exposure to these conditions can physically affect brain shape and cause cognitive decline. On top of environmental causes, having family history is also crucial in AD. Those who have a parent or sibling that went through Alzheimer’s are more likely to develop the disease than those who don’t have this family history.

Pathways identified above are just a few amongst the thousand more pathways linked to the progression of AD and the environmental/family factors are not a definitive cause either. The worst part is that there is currently no cure for the disease. Alzheimer’s is becoming more prevalent in the aging population of several countries and is taking over the memories and independence of peoples’ entire lives. Therefore, further research must be done on other genetic components, environmental factors and family history to stop the progression of the disease.