Insulin and Alzheimer’s: Bridging the Link Between Degeneration, Diet and Diabetes

Source: https://www.ecowatch.com/dr-mark-hyman-why-scientists-now-call-alzheimers-type-3-diabetes-1882174730.html

Alzheimer’s Disease (AD)

Alzheimer’s Disease (AD) is seen throughout popular culture today and is one of the most well known neurodegenerative disease there is. AD is the most common type of dementia, and is what most people often associate the disease with. Symptoms of AD include memory issues, confusion, problems speaking and writing, alterations in mood and personality. Despite how prevalent AD is and how much research is been put behind it, there is still very much that is not known about the progress of AD and why individuals with AD are being affected.

Neurofibrillary tangles

In understanding AD there are several aspects of disease that are essential to bigger picture. Neurofibrillary tangles (NFT) are one of these. In AD one of the major issue that occurs is proteins in the brain called Tau are hyperphosphorylated. This is one of the markers that is used to diagnose AD, as the malformed Tau proteins build up there is so malfunction associated with the cells. Exactly how this happens in not known but scientists are investigating how NFTs are directly associated with AD. It is believed that some or most of the communication between neurons are blocked because of these.

AB plagues

Amyloid is often used to describe proteins that are naturally produced by the body. The specific amyloid that is observed in AD is referred to as beta amyloid (BA) and is built up because the of incorrect cutting on amyloid precursor protein (APP). This incorrect cutting causes there to be longer BA in the brain which accumulates together to form plaques that cannot be broken down.

Figure 1: This image depicts the two most common identifiers of AD in the brain. There is also an observed loss of mass of brain mass, especially in the hippocampus which is an area associated heavily with memory.

Source: http://weeklyhealthtip.blogspot.com/2015/11/the-link-between-type-2-diabetes-and.html

What else do we know?

One of the major players scientists associated with AD are the cytokines of the immune system. Inflammation is seen in individuals who have AD and the response of the immune system to lower this inflammation is to send in cytokines. These are cells that have response on another cell, in this instance to give a response to inflammation. Thinking about the relationship between AD and cytokines is much like pondering the age old question of the chicken and the egg. Increased amounts of cytokines are associated with mutated APP molecules and Tau phosphorylation and eventually leads to neuron death which is a major culprit in neuroinflammation. So was it the inflammation and BA plaques that called the cytokines or excess cytokines that started the inflammation? A bigger question lays behind this, why is there a strong relationship between AD and type 2 diabetes? What about the two strings them together?

Type 2 Diabetes (T2D)

What is it?

Type 2 Diabetes (T2D) which is also known as adult onset diabetes, is when the body no longer processes glucose properly because of insulin resistance or the lack of the production of insulin. Insulin is the molecule in the body that is response for regulating the sugar molecule glucose in and out of the cells. Although T2D is more common in adults, as childhood obesity increases so does the chance of developing the disease. There is no cure for T2D but can be regulated through healthy eating and exercising.  

Figure 2: The connection between the brain and body is undeniable but eating healthy not only helps with the regulation of T2D it also increases the overall sense of wellbeing and may help the brain in the long run, much longer than some people may think.

Source: https://www.medindia.net/patients/lifestyleandwellness/diet-and-alzheimers-disease.htm

Diet and Diabetes

As seen through ways to live with T2D, diet plays a large role. It is important for individuals with T2D to take insulin shots to increase the amount of insulin in the body but in addition to this, as stated above, taking careful notice of the food that you put into your body. As seen with younger individuals, those who experience or are on the verge of obesity are at risk of developing T2D, suggesting there is some relationship between T2D and food associated with obesity. Although the exact reason for T2D diabetes is unknown to researchers there is some evidence to suggest that weight gain and unhealthy eating are apart of the cause. What most people don’t associate with this however, is AD even though there is a clear link between the two.

Figure 3: A venn diagram shows the relationship between T2D and AD by comparing the similarities between the two. As seen above, there are more things in common than many people realize. The major classifiers of AD are seen listed as well but are not observed in T2D.

Source: https://www.mdpi.com/2072-6643/7/9/5341

Insulin in Alzheimer’s Brain: Type 3 Diabetes

Insulin is so well known in the development of T2D, as well as type 1, that many people do not often realize that it plays a major role in other parts of the body, including the brain. Insulin can increase spatial memory, is essential in cognitive and memory functions, as well as influencing feeding behavior. In patients with AD less insulin is seen as well. There is also a correlatory 80% of individuals who have AD also have insulin resistance of T2D, prompting AD to be called type 3 diabetes. Although there is much more research required behind this notion, scientists urge individuals (especially those with T2D or at risk of developing it) to eat better.

Another culprit in the development of both diseases is leptin. Leptin is a hormone that is made by the body to regulate caloric intake and feeding behaviors. In one study in particular, researchers found that there mice with high fat diets did not allow leptin to bind to neurons which never alerted the body that it was full and the mice continued to eat until they were overweight. Leptin also plays a role in the insulin pathway in the brain. Mutated leptin pathways often led to insulin resistance in individuals. This suggests that high fat diets that change the structure and purpose of leptin are not only associated with diseases related directly to insulin, such as T2D, but others like AD that have less information but what is known is the lack of insulin in the brain. This shows that there is no one common link between the three but rather may remain interconnected to each other.

Figure 4: Many individuals with T2D or at least insulin resistance are at risk of developing AD.

Source; https://ediblearia.com/2016/09/11/alzheimers-disease-is-type-3-diabetes/

Many people don’t realize that changing diet now may make a difference later in life. Not only in AD and the progression of the one not only the most debilitating diseases known to man but also the hardest to watch a loved one endure. It is so important for people to understand the connection between these diseases because in doing so it may aid for them to alter their lifestyle now so that they are able to experience the best possible future.

 

References:  

https://www.alz.org/alzheimers-dementia/10_signs

https://www.brightfocus.org/alzheimers/infographic/amyloid-plaques-and-neurofibrillary-tangles

http://www.diabetes.org/diabetes-basics/type-2/

The Brain-Pancreas Connection: An Insulin Resistance Story

 

http://www.mwhomecare.com/diabetes-alzheimers-study/

What is Alzheimer’s Disease? Most likely when you first encountered Alzheimer’s, you heard that it was an individual forgetting things that they had previously known, such as names, events, or even large portions of their lives. The first thought after that is probably: Why? How does this happen in a person’s head? There are two big things that have been found to contribute to Alzheimer’s: neurofibrillary tangles and Aβ plaques.

Neurofibrillary tangles are hyperphosphorylated aggregates of tau protein that come together as insoluble clumps due to problems caused by insulin resistance. These insoluble tangles increase toxicity in the brain and cause neurons in the brain to die. With less neurons in the brain, connections are less easily made and symptoms of Alzheimer’s start to show.

Aβ plaques are collections of amyloid beta peptide oligomers that clump together because of improper cutting of an amyloid precursor protein (APP). This improper cutting is due to a buildup of the GM3 ganglioside. This also causes the insulin receptor to be unable to receive insulin. Then insulin resistance increases.

https://healclinics.com/a-relationship-between-diabetes-and-alzheimers-disease/

Now how does this relate to Type 2 Diabetes? The answer is insulin resistance. Type 2 Diabetes is characterized as your body being unable to use insulin in the correct way. When it can’t be used, it can’t regulate our blood sugar levels causing hyperglycemia, or higher blood sugar levels than normal. We know that insulin is important in maintaining our blood sugar levels; but being a big part of the brain? That is a new idea. Insulin is made in two parts of the body: the pancreas and the brain. It is an important regulator of brain physiology and works as a cognitive enhancer. So if there is resistance to this cognitive enhancer, there will be breakdown in the brain: Alzheimer’s Disease. We see that both the neurofibrillary tangles and Aβ plaques are fundamentally involved in some way, shape, or form with insulin resistance.

http://www.drugood.com/2018/05/30/is-alzheimers-disease-called-type-iii-diabetes/

Now that we have talked a little bit about both Alzheimer’s and Type 2 Diabetes, we can see that there is a connection between the two. That connection being insulin resistance. However, it goes even deeper. Studies show that 70% of all individuals that have Type 2 Diabetes will develop Alzheimer’s Disease at a later time in their lives. That number is staggering to me and it makes me think we need to make some changes at both the individual and societal levels. Individually we need to think about what we eat and get more exercise. Since Type 2 Diabetes is largely characterized by unhealthy eating and lack of exercise, this would be the obvious place to begin. At the societal level, we need to have healthy options available as fast options, not only unhealthy options. Though much of our society is in a “go-go-go” mode, we still need to have a healthy food to fuel us through our days. Though this won’t completely fix the problem, it will likely be worth it to slow down the large numbers that are developing Type 2 Diabetes and in the future Alzheimer’s. I feel that this ‘risk’ of healthy eating and exercise is worth it to remember loved ones and large events that happen in your life.

Alzheimers and diabetes, the consequences of our lifestyle

Alzheimers is a neurodegenerative disease in individuals that are usually of an older age. One of the major components to Alzheimers disease (AD) is the role of insulin. Insulin functions in our bodies to regulate uptake of glucose for cellular processes. In neurological functions, it breaks down Aβ amyloid plaques. though if there is a lack of insulin, this results in plaque formations leading to tau plaques. These plaques result in loss of neurons, as these can prevent the proper function of the neurons.

Insulin resistance develops from an excess of GM3 gangliosides building up in the phospholipid membrane, causing dissociation of the GEM insulin receptors from the caveolae.

This lack of insulin signaling leads to a lack of glucose in individuals with type 2 diabetes, a disease that is more common in obese and overweight individuals. These diseases share many components, such as a resistance to insulin. These diseases prevalence will only become more taxing on our society, as the projected numbers for the US ranks 50% of the population to be classified as overweight or obese by 2030. This increase in the affected population will also increase the number of individuals that are at a much higher risk for AD and type 2 diabetes. The State of Obesity lists the average percentage of adults in the US is 30% in most states. With several states having 35+% of the population being considered obese. In a projected 13 years for that percentage to gradually increase to encompass more of the population.

So what can we do to prevent this?

Our lifestyle choices play a major component in the development of bad habits, which can result in becoming overweight. Once overweight, this greatly increases the risk for type 2 diabetes. Since the relationship with type 2 diabetes and AD, this also increases the chances for someone who has type 2 diabetes or is overweight to be at risk for AD.

So to take preventative measures at a younger age, as preventing one from becoming obese or overweight by being active and eating a healthy and balanced diet. As these factors become more substantial at an older age.

 

Can you EAT your way into Alzheimer’s?

Did you know that 70% of people with type II diabetes are later diagnosed with Alzheimer’s? That is a ridiculous percentage to be coincidental, but what could these two diseases possibly have in common? Well, recent studies have linked both diabetes and Alzheimer’s to unhealthy diets high in fats and sugar. These unbalanced diets can then lead to detrimental factors such as insulin resistance, the degradation of your blood-brain barrier, and inflammation. Let’s take a closer look at how your diet can affect these three ailments.

Insulin Resistance:
Insulin is a natural hormone produced in the body when blood glucose levels are too high. It signals for the uptake and storage of glucose from the bloodstream to cells on the brain, liver, muscles etc. It is a very important biological function that can be disrupted if too many gangliosides (specifically GM3) have been incorporated into one’s diet. Glycosides are modified lipids that are found inside cell membranes and play an important role in cell signaling and communication. Unfortunately, if there becomes an abundance of GM3s in the membrane, they can disrupt insulin signaling by separating insulin receptors from their secondary proteins. This halts the signaling cascade and prevents the cell from intaking excess glucose resulting in insulin resistance. Excess GM3s also play a crucial role in the feedback production of amyloid beta (Ab) peptides. Once GM3 is degraded into GD3, it signals for more Ab peptides to be produced into the extracellular matrix (ECM). Therefore if there is a continuous integration of new GM3 into our membranes, the concentration of GD3s will rise leading to an increase of Ab peptides in the ECM. This can then lead to aggregation of these peptides which results in Ab plaque formation which is a classic trademark of Alzheimer’s.

Blood Brain Barrier and Chronic inflammation:
Another important factor in both Diabetes and Alzheimer’s is chronic inflammation that causes irreversible cell damage over time. The million dollar question is what causes the inflammation? Some research has pointed to clues within the gut-brain-axis which is a model showing how the gut can affect brain function. Simply the gut-brain-axis states that toxins, molecules, or anything else we digest can more easily get into our bloodstream if our gut’s microbiota is out of whack. This then can lead to extreme problems if our blood brain barrier (bbb) is damaged letting dangerous chemicals enter into our brains and cause inflammation. Microbiota imbalance can be caused by numerous factors including genetics and our daily diet. A diet high in fat, sugar, and sodium can also lead to fat accumulation which has also been shown to degrade our bbb. Without the protective covering of astrocytes around our blood vessels, which make up the bbb, the foreign molecules are free to wreak havoc on our brains. The inflammation response then hyper-activates the processing of Ab Proteins placing a higher concentration of Ab peptides in the ECM. With a higher concentration of Ab peptides, comes plaque formation and eventual neuronal death causing impairment in brain function and Alzheimer’s.
Besides the accumulation of plaques, Ab peptides trigger the production of cytokines which are the signaling molecules for inflammation creating a vicious cycle. If we could one day stop the cycle of inflammation in the brain before serious damage has occurred then we could theoretically treat Alzheimer’s. Other interesting fields of study could include bbb repair, fixing the gut microbiota in Alzheimer’s patients, and the degradation of excess Ab peptides.
However, for now, the biggest preventative strategy for Alzheimer’s and type II diabetes is a healthy lifestyle and diet. What we put into our body’s today will come back to affect our quality of life in the future.

From Alzheimer’s to Diabetes: What is the Connection?

 

picture created on wordart.com

It is no secret that Alzheimer’s Disease can be debilitating to an individual as well as to their loved ones. People look for genetic ties to the disease and early signs of memory loss or decline. However, what if there are more connections to Alzheimer’s other diseases that we thought? Below we discuss Alzheimer’s Disease and Type 2 Diabetes, the connection between them, and why this connection really matters.

Alzheimer’s Disease: What is it, really?

Alzheimer’s Disease (AD) is a progressive disease of the brain which destroys memory and cognitive and mental functions. AD accounts for 60 to 80 percent of dementia cases, according to the Alzheimer’s Association. Unfortunately, the cause of AD is still not greatly understood despite years of research. This is mainly because of the multiple factors that contribute to AD. With other diseases, researchers have found one to two causations for that disease. But AD has so many possible causations that there is no set cure. Symptoms for AD include difficulty in remembering events, in finding commonly used words, in multiple-step tasks as well as signs of depression, agitation, and apathy.

Type 2 Diabetes:

Type 2 Diabetes is a metabolic disorder where your body either does not produce enough insulin to maintain glucose level or it resists the effect of insulin. Doctors find Type 2 Diabetes in patients by looking at laboratory tests of glycemia levels. Symptoms for Type 2 Diabetes can range from blurred vision, increased hunger and thirst, and fatigue. Similar to Alzheimer’s Disease, there is no cure for Type 2 Diabetes. However, in contrast to Alzheimer’s Disease,  people with Type 2 Diabetes can manage their disease well by exercise, a healthy diet, and insulin therapy and medication.

 

How are these two connected?

Many longitudinal research studies have shown that adults with Type 2 Diabetes have a higher risk of developing Alzheimer’s Disease later on. There have also been studies showing that Type 2 Diabetes may develop due to a high-fat and high-sugar diet as well as obesity. These studies have been helpful in linking factors such as poor diet to high blood sugar and high blood sugar to inflammation in the brain. In both diseases, insulin and inflammation play major roles in the development. In AD, amyloid-beta plaques require more production and eventually lead to response in the cell to maintain overproduction. This inflammation can lead to more production of cytokines and eventually to stress and cell death, which is common is brains of AD patients. You can see the outcome of cell death in the cross-section pictures of the brain where the AD brain has deteriorated greatly. Inflammation in Type 2 Diabetes mainly is derived from over-nutrition or overeating. This excess nutrition induces insulin resistance, thus adding to one of the biggest problems in Type 2 Diabetes.

Studies have show that insulin interacts with amyloid-β protein and tau proteins. These are the proteins that eventually make up those plaques and neurofibrillary tangles that are found in brains of those with Alzheimer’s Disease, especially those with early-onset Alzheimer’s Disease. Combining this information with the face that people with insulin resistance in their body has 5-7 times more insulin than a body without insulin resistance. To learn more about insulin and its connection to these two diseases, watch this video. https://www.youtube.com/watch?v=NlbdMb8oGDo

So what?

Some might be wondering why all of this matters. Why should we care about the link between these diseases, especially if there aren’t any members of our families that have a history of Alzheimer’s Disease or show signs of Type 2 Diabetes? The answer is that this matters for our health and for our loved ones. Most people reading this have witnessed, first-hand, the impact that Alzheimer’s Disease and dementia have on the one enduring it as well as those surrounding the patient. This disease affects far too many aging people. In addition, this matters to people dealing with Type 2 Diabetes. If one has been struggling with this disease for a decade and is beginning to struggle to retrieve short-term memories, this can be incredibly alarming to them. Informing people about the warning signs of the two diseases as well as the connection between them can alert their families to focus more on diet, exercise, and being mindful of the factors leading to these two diseases. As research continues to develop for these diseases, our hope is the community surrounding those suffering will be willing to be more proactive.

 

“Grandma… it’s October”: What is happening to our relatives with Alzheimer’s Disease?

We all know someone who has been affected by Alzheimer’s disease: maybe a neighbor, a family member, or even a teacher/mentor. Alzheimer’s is a terrible disease that slowly takes away a person’s ability to function by increasingly disintegrating the neurons and their connectivity. But what IS happening when a person has Alzheimer’s disease? Why is this illness almost inevitable in the United States? And how can we stop it?

It is believed that Alzheimer’s occurs in people when there is plaque build-up from neural tangles in the brain. In recent studies, scientists have found a correlation between those with type-2 diabetes and Alzheimer’s. People with type-2 diabetes (T2D) have a resistance to insulin, the hormone that decreases glycogen levels in the body. Studies have found that the insulin signaling pathway is also essential to forming memories and preventing Alzheimer’s disease (AD). Here are a few theories on why:

TNF-alpha (a cell signaling protein involved in systematic inflammation and is a cytokine that reacts to danger) mediated inflammation:

  • ABOs cause inflammation
  • Cause insulin resistance
  • Brain inflammation mediated by microglia
  • Impairs synaptic function
  • Intersects with ER stress

Unchecked PTP1B activity:

  • Upregulates neuroinflammation-PTP1B positive regulator of microglia-mediated neuroinflammation
  • Down regulates brain insulin, leptin ( found in hippocampus and prevents plaque build-up) and BDNF (growth of neurons) signaling
  • Impact synapse dynamics and stability and cognition
  • ER stress is associated with peripheral insulin resistance in inflammatory conditions

Deregulated mTOR signaling:

  • Increase uncoupling of IR and IRS (insulin receptors)
  • Retro inhibits IRS-1 (insulin receptor substrate)
  • Impairs synaptic plasticity and cognition
  • Deregulates autophagy
  • Causes cell cycle re-entry

Aberrant ganglioside metabolism:

  • Increase of GM3 & GM1 (gangliosides) causes the uncoupling of IR & IRS-1 and accumulation of ABOs which can turn into tangles which then turn into plaques
  • Impairs AB aggregation
  • Serves as receptors for AB in the membrane
  • Required for ASB synaptotoxicity

What can we do to fix it?

Because we are seeing a correlation between T2D and AD, why not use T2D medications to treat AD? Insulin and Metformin are two drugs that scientists are experimenting with to see if they decrease the risk of developing AD in the future.

  • Insulin:
    • It is recognized that in patients with AD, the amount of insulin signaling in the insulin signaling pathway is very low. Using insulin injections, typically used for diabetes patients, studies have shown improvements in memory. For many of the studies, the insulin is more effective for older patients compared to younger ones. The insulin can be delivered two different ways: intravenously and intranasally.
      • Insulin infusion “is achieved using the hyperinsulinemic-euglycemic clamp method, where circulating insulin levels are raised by a controlled infusion of insulin while glucose levels are monitored and maintained constant through glucose infusion” (Morris, 2012).
      • The intranasal is a new process that is still being tested of its effectiveness. Instead of using the bloodstream to deliver the insulin, administration of the drug is done through the olfactory and trigeminal pathways. This new way of delivery is thought to be better as it is less invasive and less painful. By avoiding the bloodstream, intranasal delivery of insulin does not risk causing hypoglycemia in the patient.

Caption: “Insulin signaling deficits in AD brain. Several studies have compared insulin signaling in nondemented and AD subjects in postmortem brain tissue. Deficits in insulin signaling associated with AD include decreased expression of insulin receptor, insulin receptor substrate (IRS), phosphoinositide 3-kinase (PI3K), and AKT and decreased AKT activity (phosphorylation). Preclinical studies have also shown that amyloid beta (Aβ) can compete with insulin for insulin receptor binding and impair interaction of AKT and phosphoinositide-dependent kinase (PDK1). Because glycogen synthase kinase-3 (GSK-3) lies downstream of AKT, it is possible that these effects could influence tau phosphorylation” (Morris, 2012)31

  • Metformin:
    • After seeing the correlation between those with T2D and AD, the thought was to use other medications that alleviate the effects of diabetes to potentially help with Alzheimer’s. Metformin is a common drug used in cases of mild diabetes. It works by activating the AMP-activated protein kinase with then proceeds to inactivate the mTOR/p70S6K-mediated negative feedback loop to insulin receptor substrate-1 (IRS-1) , thus enhancing insulin signaling. AMPK also regulates tau phosphorylation, Aβ production, and autophagy, all of which are critical processes in AD. Metformin has also been shown to cross the blood-brain barrier. There has been some controversy over whether or not metformin is an effective way to treat AD. A study in Taiwan took people with T2D and treated them with various types of diabetes medications. Compared to all of them, metformin did the best in reducing the hazard ratio, decreasing from 1 to 0.76 (Koenig, 2017)32. However, metformin can also decrease the amount of vitamin B12 in the body, which is a risk factor to developing AD. In a study where vitamin B12 was regulated, metformin made no difference in preventing AD33.

 

I sincerely hope that a cure for Alzheimer’s disease is discovered very soon. I was recently on the phone with my best friend, my great-grandmother, who is 92 years old. She has been doing great for her age, still living alone in a duplex apartment. I notice that she often tells the same stories to me every time I visit, but I have never been too worried about that. The last time I talked to her on the phone, she completely forgot what month it was. She thought it was still summer and that school had not started yet. Once I corrected her and she was no longer confused, she told me to not tell anyone that she made that mistake. It scares me because I know that AD is a fast-moving disease and it won’t be long until Grandma forgets more important things. I hope a cure can be found so that no one has to go through the pain of taking care of a loved one with Alzheimer’s Disease.

Citation:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476214/

https://www.alzdiscovery.org/cognitive-vitality/ratings/metformin

https://moodle.cord.edu/pluginfile.php/723477/mod_resource/content/0/2018%20AD%20and%20insulin%20signaling.pdf

The Missing Piece: Linking Alzheimer’s Disease and Type II Diabetes

Linking Alzheimer’s Disease and Type II Diabetes

The Link

When picturing an individual suffering from Alzheimer’s disease (AD) and one suffering from Type II Diabetes (T2D), these pictures look greatly different. However, zooming in past the physical symptoms and appearances, we can look closely at the specific ways these disorders work. Tied together by the mechanisms of neuroinflammation, insulin resistance, and ganglioside function, AD and T2D are more similar than we might imagine.

Image 1: The biological connections in grey can be studied between AD and T2D and represent the two-way street these disorders pave in our brains.

What is Insulin?

Insulin is a hormone generally made in the pancreas that helps our body take in glucose, which is processed and used for energy and stored in our cells for future use. In diabetes, this process does not function. In type II diabetics, insulin is produced but not able to complete the signaling pathway to intake glucose.

The Pathway:

Insulin leads to the uptake of glucose through the pathway represented in the above image. Insulin binds to the transmembrane insulin receptor (IR). This activates the IRS1, leading to a phosphorylation cascade ending with the translocation of GLUT receptors to lipid rafts (compartmentalized sections) in the membrane.

Understanding Alzheimer’s:

Alzheimer’s disease is characterized by the buildup of amyloid plaques and neurofibrillary tangles in the brain. The pathway to these malformations is complex, but has many connections to neuroinflammation and insulin resistance.

Connecting the Pieces

The pathways of AD and T2D connect through insulin resistance and neuroinflammation. The two figures below detail the complex mechanical connections between the diseases. More specific information on these topics can be found at source links 1 and 2 below.

Image 3: Insulin resistance affects the production of glucose peripherally. This dysfunction in the CNS contributes to the formation of amyloid beta plaques and neurofibrillary tangles in the brain.

 

Image 4: This pathway shows that many factors (ex: PKR, S6K, PTP18, GM3) directly inhibit the processing of insulin. The buildup of GM3 molecules physically disassociates the IR from its connection with IRS 1/2, causing reception to be halted. The GD3 molecules that are made from GM3 perpetuate the buildup of Amyloid Beta plaques, showcasing the connection to AD.

So what?

Using the connections in mechanism between T2D and AD can inform future treatment options and research in both conditions. Seeing the parallel nature in pathophysiology between the conditions, it isn’t surprising how often the two disorders overlap. The knowledge gained from a dual-perspective view at both AD and T2D can influence further research in not only these conditions, but also other neurodegenerative conditions involving neuroinflammation due to the buildup of malformed molecules in the brain. This research has the potential to impact a large community of individuals and family members who are affected by neurodegenerative diseases or Type II Diabetes.

Sources for further research

The Genes of Alzheimer’s Disease

The Concordia College Neuroscience Program aims to consider and connect as many interdisciplinary perspectives as possible. As students, we are taught to think critically and connect our experiences to the curriculum. This perspective helps in discussing the possible causes and connections in neurodegenerative diseases. When discussing Alzheimer’s Disease this week, the class considered the similar pathways and concepts we learned last week with Autism Spectrum Disorder (ASD). Students also considered their personal connections and experiences with neurodegenerative diseases.

Although we have all learned about Alzheimer’s Disease in our courses, many of us also have personal connections to the neurodegenerative disease. According to the 2018 facts and figures released by the Alzheimer’s Association, 5.7 million Americans currently live with Alzheimer’s Disease. The number of deaths related to Alzheimer’s Disease has increased by 123% from 2000-2015. The association notes that every 65 seconds, another individual develops Alzheimer’s Disease in the United States. Cases of dementia, including Alzheimer’s Disease, are responsible for the death of 1 in 3 senior Americans–this is more than Breast Cancer or Prostate Cancer combined.

Like a few of the other students in the class, I have a familial connection to Alzheimer’s Disease. Due to many members within the older generation of my family developing Alzheimer’s Disease, I fear that I too may develop the disease in the later years of my life. We know from previous research that there is a hereditary factor linked to Alzheimer’s Disease. Previous research has shown that mutations in genes APP, PSEN1, and PSEN2 have linkages to early onset Alzheimer’s. Likewise, research on late-onset Alzheimer’s Disease found 20 different genetic loci associated with the disease. Specifically, APOE4 is a gene correlated with the familial development of Alzheimer’s Disease–one that shows the heritability of the disease. Regardless of the heritability and genetic factors of dementia, previous research has also shown the importance of the environmental factors associated with the development of the disease–and in many cases, the genetic and environmental factors both contribute to the development of Alzheimer’s Disease. Paying attention to these environmental factors may decrease my chances of developing this neurodegenerative disease.

These environmental factors include:

  • Diet
    • Type 2 Diabetes has been linked to Alzheimer’s
    • The insulin resistance leading to Type 2 Diabetes likely stems from a fatty diet
    • Other popular media articles have discussed how red meat might lead to Alzheimer’s
    • The prevalence of Alzheimer’s Disease in the United States more than likely is due to our diet and lack of exercise.
  • Exposure to toxic chemicals
  • Serious brain injury
  • Air pollution

When discussing Alzheimer’s Disease and many other neurodegenerative diseases, it remains important to note the vital interaction between genetic and environmental factors resulting in the development of disease. With the prevalence of genetic testing in today’s society, specifically through companies like 23andMe, people can know in approximately 6-8 weeks if they possess some of the genes associated with Alzheimer’s Disease. Without proper consideration or education, members of society may be mislead to think that they are destined to develop the disease. That may not be the case. It is more likely that even if an individual possesses the gene associated with a disease, environmental factors play a large role in whether or not that gene is transcribed or “turned on.” Research has shown that paying attention to the environmental risk factors above, and changing lifestyles to match, may reduce a person’s risk for Alzheimer’s Disease.

https://moodle.cord.edu/pluginfile.php/723477/mod_resource/content/0/2018%20AD%20and%20insulin%20signaling.pdf

https://www.alz.org/media/HomeOffice/Facts%20and%20Figures/facts-and-figures.pdf

 

An Unlikely Relationship: The Link Between Alzheimer’s Disease and Type 2 Diabetes

In a society that values convenience, it should not come as a shock that 1 in 4 Americans eats fast food every day. Aside from poor eating habits, it has been found that nearly 70% of one’s waking hours are spent being sedentary, and yes that is referring to the copious amount of time you spend on the couch binge watching Netflix. Taking all of these factors into consideration, it is not surprising that nearly 40% of Americans are obese, not simply overweight, but obese. The more weight that an individual has, the greater the risk of their body becoming resistant to insulin, and developing type 2 diabetes. And if the threat of developing type 2 diabetes isn’t enough to consider changing your lifestyle, maybe learning that it nearly doubles your chances of developing Alzheimer’s Disease will.

It’s time to start spending less time in the McDonald’s drive thru, and more time thinking about your health.

How are Type 2 Diabetes and Alzheimer’s Disease related anyway? The Power of Insulin

Insulin is a hormone that is created in the pancreas that plays vital roles throughout the entire body. Not only does it maintain proper blood sugar levels, but it also assists the body in using and storing energy depending on its metabolic needs. Insulin is what turns your Big Mac into energy that your body can use. 

Image result for grand big mac
https://www.google.com/search?q=grand+big+mac&source=lnms&tbm=isch&sa=X&sqi=2&ved=0ahUKEwjo9ezBpvjdAhUKTcAKHUV1BTcQ_AUIDigB&biw=1440&bih=826#imgrc=fmyEcPsLjNyMyM:

Insulin Resistance: What happens when insulin can’t do it’s job?: The link between Type 2 Diabetes and Alzheimer’s Disease

So if type 2 diabetes (T2D) is defined by insulin resistance, how does that relate to Alzheimer’s Disease (AD)?

Insulin has a special role in the brain. It works to protect neurons, strengthen connections, and plays vital roles in cognition and memory. If insulin can’t function in the brain, these processes are disrupted.

(Memory loss and impaired cognition are two symptoms of Alzheimer’s Disease)  

The brains of AD patients usually have two main “tell-tale” signs signifying that Alzheimer’s was present: amyloid-beta plaques and neurofibrillary tangles.

alzheimers-plaque-az
https://www.askdoctork.com/how-does-alzheimers-wreak-so-much-havoc-in-the-brain-201506258011

It is believed that insulin resistance in Alzheimer’s Disease may be the result of an accumulation of these amyloid beta plaques in the brain, and in supporting this theory, there are many additional hypotheses as to how this insulin resistance develops in the brain.

TNF-α and Inflammation

It is believed that prolonged inflammation is responsible for insulin resistance in both T2D and AD.

In Type 2 Diabetes: As mentioned above, being obese has been linked to the development of T2D. It’s simple: as fat cells accumulate, inflammatory molecules also accumulate, and one of the instigators of this inflammation is a pro-inflammatory cytokine known as TNF-α. 

In Alzheimer’s Disease: Prolonged inflammation is often a defining characteristic in Alzheimer’s brains. This inflammation is often the result of immune cells in the brain known as microglia. These cells often release inflammatory molecules in response to the accumulation of the amyloid beta particles described earlier. Interestingly enough, research has shown that in order for these amyloid beta instigators to cause insulin resistance in AD patients, the TNF-α receptor must be present.

It’s a fairly reasonable conclusion that the inflammatory mechanisms of TNF-α may explain the prolonged inflammation causing inadequate insulin signaling in both AD and T2D.

And there you have it, a link between two unlikely partners in a toxic relationship. 

Figure 1
http://diabetes.diabetesjournals.org/content/63/7/2262.figures-only

Figure 1. This image depicts inflammation in the brain and periphery mediated by TNF-α and its relationship to AD and T2D.

Gangliosides and Insulin Resistance

Gangliosides have also been found to play an important role in insulin resistance.

Ganglioside GM3:

Insulin resistance mediated through TNF-α, as described above, is dependent on the accumulation of GM3.

  • As GM3 accumulates in the cell membrane, it causes tension that pulls insulin receptors out of their normal location.
    • It is believed that the accumulation of GM3 is the result of amyloid beta plaques interfering with proper ganglioside metabolism.
  • When insulin receptors are no longer in the correct spot, they become unrecognizable to the molecules that play a role in insulin signaling.
  • When proper signaling can no longer occur, insulin will not be able to perform its functions in the body, and insulin resistance will result.
http://www.pnas.org/content/104/34/13678

Figure 2. This image displays the accumulation of GM3 rendering proper insulin signaling defective.

Ganglioside GM1:

The ganglioside GM1 is a binding site for amyloid beta oligomers (ABOs) and is thus responsible for the accumulation of ABOs into toxic amyloid beta plaques. Interestingly enough, research has found that diabetes increases the accumulation of these toxic plaques, and you have yet another link between the two diseases.

Related image
https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-researchers-find-way-to-prevent-accumulation-of-amyloid-plaque-a-hallmark-of-alzheimers-disease/

So what’s the point?

https://steemit.com/sirwinchester/@sirwinchester/you-are-what-you-eat-how-food-affects-our-mood-and-brain-health

Stop taking the easy way out when it comes to your health, it could save your life. 

  • Take some time instead of the 2 minutes you spend in the drive thru, and make a meal!
    • Here are a few recipes you can try that are SUPER simple, healthy, and relatively quick:
      • “31 Healthy Dinner Recipes that take 30 Minutes or Less”
        • visit: https://pin.it/4ejzhyj6ha7yae
  • Stop binge watching Game of Thrones on the couch!
    • You could try watching it on your phone from the comfort of an elliptical or stair climber, trust me, it works!
  • Take care of your body; you only get one, and I hate to break it to you, but health care professionals can’t cure every ailment.
    • Just so you are aware: there are no known cures for Type 2 Diabetes or Alzheimer’s Disease.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2996155/

https://www.mayoclinic.org/diseases-conditions/diabetes/symptoms-causes/syc-20371444

https://www.dosomething.org/us/facts/11-facts-about-american-eating-habits

https://www.askdoctork.com/how-does-alzheimers-wreak-so-much-havoc-in-the-brain201506258011

http://diabetes.diabetesjournals.org/content/63/7/2262https://www.healthnutnews.com/alzheimers-type-3-diabetes/

 

 

 

 

 

Here’s what you may (not) know about Alzheimer’s disease: Is your diet leading to cognitive impairment?

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by memory loss and other cognitive impairments such as thinking and behavior. AD is a type of dementia and can be very debilitating on the body of the patient and also significantly affect the relationships that one has with their family and friends.

 

 Alright, so you’re on your computer or you’re watching Netflix at home and your stomach starts to rumble and you get up to get a snack-what do you grab? Do you go for those veggies sitting in your fridge, decide to make a salad, or say “to heck with being healthy, lets eat some cake and order in Dominos.” While I love ‘junk food’ just as much as the next person, I’m not sure I’ll be reaching for that dessert as much anymore after finding out that type 2 diabetes is a major risk factor for Alzheimer’s disease. Now, just to be clear, I’m not saying that eating a continuous high-fat diet will cause you to have symptoms characteristic of dementia or AD, but I am saying that we, as a society, should start paying closer attention to what we are eating.

 

Wait, so you’re telling me that there’s a link between my diet, developing type 2 diabetes, and getting AD? How in the world is this possible? I’m glad you asked! There are mechanisms found at the molecular level that help bring this association to light, specifically in regards to insulin signaling, and inflammation.

 

Insulin Resistance Signaling

As you’re eating whatever snack you decided on earlier, the food is being broken down into smaller molecules (i.e., glucose) that can be used for energy and metabolism. When there becomes an increased amount of glucose in the body, a hormone, namely insulin, is release. This key hormone helps to breakdown glucose so that the body can use it efficiently and effectively. However, in type 2 diabetes, this entire process is inhibited in some way, thus producing insulin resistance, characterized by having insulin but lacking the proper signaling in the brain. This resistance to insulin can have some negative affects on the brain and body overall. This impaired insulin signaling happening in the brain has been detected in a post-mortem analysis of the brain (the only way to actually ‘diagnose’ AD, as well) in the hippocampus region.

 

Inflammation

This is an important part of the type 2 diabetes-AD story. Inflammation in type 2 diabetes is mediated by macrophages in adipose tissue that also intersects with ER stress and thus can also be linked to insulin resistance through the TNF-alpha pathway. However, in the brain, this notion of inflammation is mediated by microglia cells that impairs synaptic functioning, also plays a role in ER stress, and is associated with insulin resistance signaling in the brain (specifically with the insulin receptors). This problem of insulin resistance may be due to the fact that there is activation of PKR (protein kinase R) by the TNF-alpha signaling, which would further lead to a potential inhibition of insulin receptor substrate (IRS) in the PI3K/Akt pathway (more on this in a bit).

The PI3K/Akt pathway is important as it is involved in cell growth and proliferation. But what exactly is going wrong in this pathway that leads to cognitive decline and AD? This pathway is overactive in the AD brain and is not being properly shut off. Let’s take a closer look:

 

This pathway is activated by insulin and leads to a phosphorylation cascade of events that activate a number of different enzymes in the cell. When this pathway is overactive, it leads to insulin resistance in the brain, similar to what is seen in type 2 diabetes due to unhealthy eating habits. Furthermore, when this pathway is constantly being turned on, our bodies try to compensate for this constant activation by decreasing the number of insulin receptors. This ultimately means that there are less receptors for insulin to bind to, and thus less activation of the pathway. However, this essentially leads to insulin resistance in the brain and can be fatal, as mentioned above.

Figure 2. Schematic of the PI3K/Akt pathway.

This over activation can also lead to hyperphosphorylation of the tau protein in the brain-once these start sticking together too much, they create what is called neurofibrillary tangles. This excess phosphorylated tau protein and NFTs can lead to formation of amyloid-beta plaques, which are all highly characteristic of AD.

 

For more info on tau protein, NFTs, and amyloid-beta plaques: https://www.nia.nih.gov/health/what-happens-brain-alzheimers-disease

 

Finally, it has also been shown that the hormone leptin plays a major role in helping link type 2 diabetes and AD together. Leptin activates the PI3K/Akt, pathways, which aid in neuronal survival and thus decreasing tau protein phosphorylation and amyloid beta plaques. Thus, if leptin is mutated or inhibited in some way, these pathways aren’t activated, and thus leads to neurodegenerative disease, such as Alzheimer’s. Leptin receptor activation has also been shown to improve the impaired insulin growth factor cell signaling pathway (insulin receptors), thus to normalize cell repair and other processes. This would help to generate normal insulin receptor activation and thus decrease the symptoms seen with AD.

Figure 3. A research study that examined the role of a high-fat diet and the leptin pathway. They found that the mice given the high-fat diet produced the MMP2 enzyme that cut leptin receptors in the brain (hypothalamus), which thus prevents leptin from binding to its receptors. This helps to put together why your brain doesn’t tell your stomach to stop eating because you are full.

So, what? Is there a cure? What’s the big picture anyway?

 

While there is no cure for AD, it is all about helping the person cope with the symptoms, help relieve the pain and suffering, as well as provide hope for not only the patient but also the family. As you can see, it is quite evident that type 2 diabetes and AD are major risk factors for each other, and it is important to maintain a healthy diet and try to exercise regularly. It may be difficult at times to resist those McDonald’s fries, but a non high-fat diet could go a long way in preventing AD. There is still SO much unknown about Alzheimer’s, but that’s the beauty of science. With advancements in technology and understanding the pathophysiology behind AD and type 2 diabetes, there is always hope for more research to be done in the attempt to finding a cure.

 

Image 1 from: https://emedmultispecialtygroup.com/2018/03/20/alzheimers-disease-symptoms-care/

Image 2 from: https://newsnetwork.mayoclinic.org/discussion/mayo-clinic-q-and-a-identifying-alzheimers-in-its-earliest-stages/

Image 3 from: https://www.researchgate.net/figure/Aberrant-brain-insulin-signaling-in-Alzheimers-Disease-AD-Schematic-outline-of_fig1_279729041

Image 4 from: https://medicalxpress.com/news/2018-08-destructive-mechanism-blocks-brain.html

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