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TLDR: Alzheimer’s, or the disease caused by the degeneration of your neurons (brain cells), is currently being highly researched. What you should know about it is that we can now use some therapies to fight it and maybe even have some chances of a cure. These things in the body, called biomarkers, may be used to treat the disease in the long run. To understand the workings of these biomarkers deeply, you need to know about the key metabolic changes that occur in your brain during the disease: weakened neuron connections in the brain, changes in the metabolism of the brain, energy consumption, or the difficulty of repairing or remodelling the degenerative neurons.
Alzheimer’s starts with the basic symptoms of neurodegradation, which means neurons are degraded, leading to an overall continuum of mild cognitive impairment. There are more subtle cognitive changes than in someone with dementia, where people start to experience a significant change in their mental abilities and behaviour. These changes usually stretch over 15–25 years.
In mild cognitive impairment, the common symptoms in a patient include forgetting recent information like appointments or conversations, difficulty judging the sequence of steps in a complex task, forgetting material that was just read, difficulty finding the right words, losing or misplacing valuable objects, and more.
Moderate Alzheimer’s includes more symptoms like forgetting personal history, information, or events, being moody or withdrawn, confusion about where they are, changes in sleep patterns, personality changes, trouble with bladder and bowel control, and more.
However, severe Alzheimer’s includes symptoms like difficulty in communication, loss of physical abilities, loss of awareness of recent experiences or surroundings, requiring constant assistance with daily personal care, and more.
In this blog, we want to explore the science behind Alzheimer’s disease, the research that is currently ongoing, and the little ray of hope that science gives us.
The Science Behind Alzheimer’s
While Alzheimer’s is still a non-curable disease that is dreaded throughout, certain things in our body help us understand whether an individual is more prone to developing the disease. These things in our body are called biomarkers.
Amyloid Beta
One of the most important biomarkers that is associated with the neurodegradation that causes Alzheimer’s disease is Amyloid Beta. This particular biomarker helps the brain recover from injuries and protects the overall brain against bacteria, viruses, and tumours. When errors occur in the production of this molecule, it can stick to itself, leading to long-chain formation. These chains may combine and form larger structures called amyloid plaques.
These oligomers and plaques should ideally be cleared from the brain regularly, but as people age, the body becomes less able to stop them from building up. The research done on this molecule supports the hypothesis that families are directly associated with such an autosomal dominance of the disease. This means that this gene might be expressed in your entire family, making a daughter or a son more susceptible to the disease if their parents have it.
Tau
The second biomarker is Tau which is thought to be associated with the disease since it’s a key component of a neuron’s cytoskeleton, which, much like the bones, gives neurons their shape and helps them carry out their jobs. It is sensitive to changes in the brain, which means a neuron cannot function well without a healthy cytoskeleton.
Neuroinflammation is another term that you need to know about. The process that causes your skin to swell around a cut and a fever to occur when you have an infection. It helps our brain heal after infections or trauma.
The next important biomarker that we want to cover here is the Apoe gene. This particular gene is called the Apoliprotein and has a strong influence on whether a person will develop the disease. This protein determines how our cells use fat as energy. This gene is associated with other health conditions as well.
Key Biological Changes in The Brain During Alzheimer’s
What you need to understand about the brain is that the disease leads to continuous chemical changes. There are major biological changes in the brain here.
Communication:
Neurons are constantly in touch with neighbouring brain cells. When a neuron receives signals from other neurons, it generates an electrical charge that travels down the length of its axon and releases neurotransmitter chemicals across a tiny gap, called a synapse. Like a key fitting into a lock, each neurotransmitter molecule then binds to specific receptor sites on a dendrite of a nearby neuron.
This process triggers chemical or electrical signals that either stimulate or inhibit activity in the neuron receiving the signal. Communication often occurs across networks of brain cells. Scientists estimate that in the brain’s communications network, one neuron may have as many as 7,000 synaptic connections with other neurons.
Metabolism:
Metabolism—the breaking down of chemicals and nutrients within a cell—is critical to healthy cell function and survival. To perform this function, cells require energy in the form of oxygen and glucose, which are supplied by blood circulating through the brain. The brain has one of the richest blood supplies of any organ and consumes up to 20 per cent of the energy used by the human body—more than any other organ.
Repair, Remodeling, and Regeneration:
Unlike many cells in the body, which are relatively short-lived, neurons have evolved to live a long time—more than 100 years in humans. As a result, neurons must constantly maintain and repair themselves. Neurons also continuously adjust, or “remodel,” their synaptic connections depending on how much stimulation they receive from other neurons.
At first, Alzheimer’s disease typically destroys neurons and their connections in parts of the brain involved in memory, including the entorhinal cortex and hippocampus. It later affects areas in the cerebral cortex responsible for language, reasoning, and social behaviour. Eventually, many other areas of the brain are damaged. Over time, a person with Alzheimer’s gradually loses his or her ability to live and function independently. Ultimately, the disease is fatal.
