Ins and Outs of Endocannabinoids

Marijuana or cannabis. Some say it is bad, others say its good. Lets dive down deep to discover the ins and outs of the endocannabinoid system.

Cannabis is a plant that is grown and yields CBD and THC. THC activates cannabinoid receptors and leads to the common high due to the psychoactive component. More is still being learned about CBD, and it is known that it is use as a treatment option for pain. THC uses two different receptors to bind, CB1R and CB2R. CB1R is dominant in brain and skeletal muscle whereas CB1Rb has higher expression within the liver and pancreatic cells due to its involvement in metabolism. CB2R are found in the testes and lower levels in brain reward regions. Endogenous agonist (AEA) and 2-AG are important endocannabinoids that bind to both receptors.  AEA has a high-affinity and partial agonist of CB1R and inactive to CB2R. 2-AG is a full agonist against both receptors, but has a low affinity. CB1R can inhibit GABA and glutamate release from presynaptic terminals meaning it can modulate neurotransmission. This is important because CB1R plays a neuroprotective role against excitotoxicity, inhibits nitric oxide, and increases brain derived neurotrophic factors (BDNF). So how is this all beneficial or hurtful to the body?

CB1R has been observed in a variety of neurodegenerative diseases such as Alzheimer’s, Parkinson’s, and Huntington’s. In Parkinson’s, there is an upregulation of CB1R and the endocannabinoid system. In Huntington’s, there is a progressive loss of CB1Rs and worsens over time. Currently, CB1R is being looked at as a way to control appetite. The most common use of cannabinoids however is for pain. In cancer patients who are undergoing chemotherapy or radiation, they typically experience a loss of appetite. Cannabinoids are being used to help increase their appetite to maintain a healthy weight to continue treatment and increase their well being. Along with stimulating appetite, it also reduces nausea, vomiting, and alleviates pain. As mentioned above, one property of endocannabinoids is the neuroprotective effects against excitotoxicity. This is commonly associated with seizures due to the over active firing. Endocannabinoids can reduce this, resulting in dramatic decreases for those that have epilepsy. In fact, some families who have young children with severe epilepsy will move to a state that has legalized medical marijuana. In moving to these places, these families have had children or family members go from hundreds of small seizures and frequent gran mal seizures to less than a quarter of that. This shows that the endocannabinoid system can drastically reduce neurological diseases and their symptoms to increase the way of life of these people. However, there are some fears that are associated with endocannabinoids such as the addictive or gate way drug tendencies. However, cannabis does not actually have an addictive chemical like nicotine. Cannabis is considered a gateway drug but not a lot of research has been done, in fact, alcohol a frequently consumed item is considered a gateway drug.

The endocannabinoid is a complex system that is still being studied for pros and cons. A lot of the research that is now available is leaning towards more benefits than harms, especially for neurodegenerative diseases in which this system can help improve the quality of life.

 

What Causes Obesity?

What causes obesity? The popular idea is that obesity is caused by over-eating and not exercising. But why does this happen? Why do people over-eat? The exact answer to that question is unknown.

To understand why people over-eat we must first understand how normal eating works. Two important factors involved in mediating appetite are insulin and leptin. In normal metabolic homeostasis, insulin and leptin activate POMC neurons and inhibit AgRP neurons. POMC neurons are involved in satiety, while AgRP neurons are involved in eating. This leads to a balance in energy expenditure and food intake.

There are several other peptides released by the gastrointestinal system that are involved in satiety. The first factor identified was cholecystokinin (CCK). This peptide is responsible for decreasing meal size. Glucagon-like peptide (GLP) is another peptide released from this intestine in response to meals. In rodent models, GLP-1 was shown to be involved in decreasing food intake. Peptide YY (PYY) is secreted along side GLP-1 and has similar affects. One peptide, Ghrelin, is released from the stomach and is involved in stimulating appetite.

In obesity and metabolic syndrome, there is a resistance to anorexigenic signals from insulin and leptin. This means there is no activation of POMC neurons and no inhibition of AgRP neurons. This causes a decrease in energy expenditure and an increase in food intake.

A deeper question to ask is what causes resistance to leptin and insulin?

Several mechanisms for leptin resistance have been identified including gene mutation, altered transportation across the blood brain barrier (BBB), and inflammation. Though it is extremely rare, it is possible to inherit leptin resistance. This is caused by mutations in the OB and DBU genes. However, these mutations are very rare and cause hyperphagia, obesity soon after birth, and hypothalamic hypogonadism. Because it is so rare to find these mutations in the leptin gene or its receptor, this is not the main factor for the development of leptin resistance. A factor that does play a role is altered transport of leptin across the blood brain barrier. Leptin resistance at the BBB allows for unregulated transport of leptin from the blood to the brain. Excessive levels of leptin in the blood cause a decrease in BBB permeability. Another factor that plays a part in leptin resistance is inflammation. High-fat diets can induce low-grade inflammation in tissues such as adipose tissue and the liver, which can lead to an increase in inflammatory cytokines such as IL-6 and TNF-α. Leptin is also a proinflammatory cytokine in a family similar to IL-6.

Insulin resistance is also due to many factors including genetics, aging, and ethnicity. However, the biggest factors behind insulin resistance include excess body weight and lack of exercise. With insulin resistance, cells in muscles, fat, and liver can’t respond to insulin and therefore can’t allow glucose to enter the cells.

In conclusion, insulin and leptin resistance can lead to a variety of problems. One of those problems is the inability to activate POMC neurons and inhibit AgRP neurons. This leads to no feelings of satiety, decreased energy expenditure, and an increase in food intake. Eventually, this can lead to problems such as obesity and metabolic syndrome.

 

References:

https://moodle.cord.edu/pluginfile.php/798963/mod_resource/content/2/inflammation%20and%20MD%202017.pdf

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2710609/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6354688/

https://www.endocrineweb.com/conditions/type-2-diabetes/insulin-resistance-causes-symptoms

https://www.niddk.nih.gov/health-information/diabetes/overview/what-is-diabetes/prediabetes-insulin-resistance

Image sources:

https://moodle.cord.edu/pluginfile.php/798963/mod_resource/content/2/inflammation%20and%20MD%202017.pdf

https://www.the-scientist.com/features/breaking-the-cancer-obesity-link-34583

Cannabis: Miracle Drug or Potential Poison???

The debate of whether or not cannabis should be used for recreation has been raging for well over a decade now, and there are strong arguments on both sides. People in favor of recreational marijuana point to research that shows the extensive benefits of the plant, while those opposed call cannabis a “gateway drug” and point to the conflicting data in the scientific community surrounding the substance. With the topic being so prominent, the fact that the sciences can display cannabis as a cure and poison is extremely interesting.

This is conflicting representation is most likely due the lack of scientific research regarding the substance. Cannabis interacts with receptors of the endocannabinoid system which has several important functions in the body. The most widely studied receptors of this system are the CB1 receptor and CB2 receptors, which can be found both in the brain and in peripheral nervous tissues and cells.

The abundance of these receptors throughout the body are one of the major obstacles when determining the effect of Cannabis on the human body. For example the CB1 receptor has been found in the brain, cardiovascular system, liver, GI tract, and reproductive systems. Therefore administration of cannabis affects the body in several ways simultaneously making it difficult to study. Recent studies have attempted to demonstrate the effects of marijuana on several diseases.

Zou, S., & Kumar, U. (2018). Cannabinoid receptors and the endocannabinoid system: signaling and function in the central nervous system. International journal of molecular sciences, 19(3), 833.

The CB1 receptor has been found to inhibit GABA and Glutamate release in which directly impacts neurotransmission. This is proposed as a plausible underlying mechanism of CB1-mediated neuroprotection against excitotoxicity, a prominent pathological process of many disorders such as epilepsy, Alzheimer’s disease, Parkinson’s disease.

In Parkinson’s disease the up regulation of  the CB1R and endocannabinoid system  activity which could be a mechanism to compensate the degenerated dopaminergic neurons, or a pathological process that contributes to the worsening of the disease. In addition, the activation of the CB1 receptor has been shown to be beneficial in Alzheimer disorder animal models with memory deficits and cognitive disorders. However, results from these models are still debated in the scientific community.

The conflicting data is not the only problem however. Marijuana is currently considered a schedule 1 drug. This means that in the eyes of the law and the government, cannabis is in the same class as heroin, LSD, and ecstasy. This classification has several impacts on the scientific communities ability to research the effects of the drug. For instance, in order to perform research on a schedule 1 drug, there are mountains of paperwork and regulations which must be addressed. This makes the already expensive research even more expensive and time consuming. This leads to limited research on a drug that has the several possibilities in regards to several crippling diseases.

The effects of cannabis on the human body is still uncertain. Several studies have shown remarkable effects of the drug , while other studies have shown the drugs potential to exacerbate several diseases.  This uncertainty is a product of conflicting experiments as well as limited research. In order to determine whether or not cannabis is a miracle drug or a potent poison, further research is needed.

Sources:

https://www.ncbi.nlm.nih.gov/pubmed/28827089

 

Endocannabinoids: More than Understanding Marijuana?

Marijuana has long been used recreationally and medicinally. While its recreational use is still of debate, its medicinal properties have also come under great study, especially in recent years. The active components in marijuana act on the bodies endocannabinoid system, comprised of the receptors cannabinoid receptor 1 and 2 (CBR1 and CBR2). There are around 70 phytocannabinoids that have been identified in the marijuana plant, but ∆9-tetrahydrocannabinol (THC) is the main psychoactive component. THC has long been the barrier to effective medicinal use of marijuana, although deeper research suggests there are additional hurdles.

Endocannabinoids

Endocannabinoids, or the endogenous agonists of the CBRs, in the human body are anandamide (AEA) and 2-arachnidonoylglycerol (2-AG). These are the chemicals that are synthesized inside the brain and act on the CBRs in response to various signaling events. CBR1 is the dominant receptor in the brain and muscle, with other isoforms in tissue like the liver and pancreas. CBR2 is present in brain reward regions, the testis, and spleen, depending on the isoform. Because there are multiple forms of both receptors and they are expressed at significant levels in many different tissues, it becomes more difficult to target a specific response from the endocannabinoid system. Depending on the endocannabinoid, they also act and target the receptors differently. AEA has been shown to be a high-affinity partial agonist of CBR1, meaning it binds at low concentrations but only has a partial effect; it is also almost entirely inactive at the CBR2. 2-AG, however, acts as a full agonist of both receptors but at moderately low affinity. Both endocannabinoids are produced on demand in response to increased intracellular Ca+2 concentrations, which means this system can be activated from a variety of upstream effects. The full paper that reviews these topics and more can be found here. 

Medicinal Use of Endocannabinoids

The effects of the endocannabinoid system based on single cell activation is extremely varied, as is demonstrated in this graphic.

Zou, S., & Kumar, U. (2018). Cannabinoid receptors and the endocannabinoid system: signaling and function in the central nervous system. International journal of molecular sciences, 19(3), 833.

Not only can these receptors be activated by a ligand binding on the extracellular side, but there has also been activity shown on internally localized receptors, whether those were taken in through endosome processes or if they were intrinsically localized on a lysosome or mitochondria. This is another reason why targeting the CBRs for medical use is difficult.

Zou, S., & Kumar, U. (2018). Cannabinoid receptors and the endocannabinoid system: signaling and function in the central nervous system. International journal of molecular sciences, 19(3), 833ys 

Cell signaling pathways through β-arrestin and other methods result in different cellular effects that might be off of the intended process. In addition to their highly distinct roles and locations in the cell, they are also found around the body with different affects, depending on the location and cell type.

 

What does it mean?

In the end, while medical marijuana is currently being marketed as a miracle for conditions from multiple sclerosis, to seizures, to palliative cancer care, the science is less clear. Our understanding of the signaling processes, especially the non-GPCR alternate pathways, is limited. Until we are able to elucidate the pathways more succinctly and understand the downstream effects, positive development of cannabinoid pharmaceuticals will be limited.

 

 

Don’t Think with your Gut

 

 

Introduction 

If someone had advocated for the legalization of recreational marijuana a few decades ago, he or she would have laughed at. After all, marijuana is a drug and drugs are bad. Yet, over the years research has appeared that contradicts this. Suddenly, there is debate on whether marijuana has any medical uses and whether or not it should be legalized, both recreational or medically.

Recent studies and testimonials from patients discuss how marijuana may be useful in treating epilepsy, cancer, AIDS, and other disorders. There is also a growing body of evidence that marijuana may not be as harmful as previously thought. But yet, there is still a strong stigma against marijuana. Is the drug really deserving of all this controversy?

Endocannabinoids

In general, most chemicals and neurons in the brain can be classified as excitatory or inhibitory. Excitatory means that it increases the likelihood of a signal firing. Inhibitory decreases the likelihood. Depending on the context, marijuana is capable of both.

The two main chemicals in marijuana: THC and CBD act on a little-known signaling system in the nervous system. They act on the endocannabinoid system. Now, THC and CBD are obviously not something that is naturally produced by the human body. Rather, neurons in the cannabinoid system produce 2-AG and AEA. These chemicals act on the two receptors: CBR1 and CBR2. AEA causes a response at CBR1, but does not too much when bound to CBR2. 2-Ag acts strongly on both receptors. Of these two chemicals, AEA is the more well-studied, yet 2-Ag is more prevalent in the brain.

 

[i]

[i] https://www.neurologylive.com/journals/neurologylive/2018/october-2018/exploring-cb1-cb2-various-neurological-conditions

 

Imagine two neurons in the brain. Normally, the signal flows from the upstream neuron to the downstream neuron. Sometimes the upstream neuron sends a signal to the downstream neuron to get it to stop firing. However, this causes calcium to build up in the second neuron, which really wants to fire. The second neuron than releases 2-AG to the upstream neuron that shuts off the inhibition. This happens because 2-AG binds to CBR1 and closes the calcium channels. This can lead to excitation or inhibition, depending on what the upstream neuron was doing. If the upstream neuron was inhibiting the downstream neuron, then the signal is now excitatory. If the upstream neuron was excitatory, the signal is now inhibited.

That all seems fairly simple. However, the exact nature of the individual receptors complicates things. CBR1 can actually increase cAMP in some cases. (cAMP is typically inhibited if calcium is inhibited). In most cases, the CBR1 receptor inhibits calcium channels and is involved in inhibiting GABA, the primary inhibitory neurotransmitter in the brain. Additionally, CBR1 is heavily involved in cell proliferation and death. The receptor regulates MAPK signaling pathways including ERK and JNK. (For a summary of these pathways, click here). Essentially, activation of these pathways increase brain -derived neurotrophic factor (BDNF) which aids in cell survival.

Treatment of Various Disorders

Marijuana has come to attention today partially because of its possible medicinal properities. Indeed, drugs that act on the CBR1 receptors have been helpful in treating disorders like Huntington’s disease and Parkinson’s, which arise from an imbalance of glutamate and GABA in the brain. Drugs like marijuana are able to reset this balance.

Additionally, marijuana may aid in treating pain, lack of appetite, and seizures. Some research indicates that overeating and seizures may be linked to dysfunctions in the endocannabinoid system. The appetite stimulating effects come from the CBR1’s ability to activate the POMC neurons and release several hormones involved in eating. Little is known about how exactly CBR1 drugs are able to stop pain, but it likely involves CBR2 and the receptor TRPV1. CBD is mainly responsible for this effect, as it indirectly inhibits the CBRs. Normally, this regulates the effects of THC, controlling the potency of marijuana.

 

Why the stigma matters

Even with all that science, there is still a lot unknown about marijuana. The effects of chronic usage are still debated. However, there may very well be some benefits to it.

Marijuana is currently classified as a Schedule I drug. This classification is often cited for the main reason that marijuana research is hard to come by in the United States. However, heroin is also a Schedule I drug and it is more well-studied. It is possible to study Schedule I drugs. Marijuana simply gets more heavily stigmatized.

Like all stereotypes and stigmas, this one causes harm. There are a lot of people who could benefit from medical marijuana. The drug is by no means a magical solution to these disorders, but it may help those suffering from them.

It is human nature to fear the unknown and there is certainly a lot unknown about marijuana. It is often people’s gut instinct. But, doing so often causes people to make hasty, often harmful generalizations. Marijuana is not deserving of all this controversy, but rather curiosity. Instead of following the gut instinct to fear the unknown, we should use our heads to study it.

[ii]

[i] Cannabinoid Receptors and the Endocannabinoid System: Signaling and Function in the Central Nervous System.

 

 

The Endocannabinoid System – A Glimpse into the FUTURE!

Many of us wonder where we will be in ten, maybe twenty years from now regarding our health. What will the health care system look like? Will it be improved? What advancements will be made that prolong life as well as improve quality of life?

Let’s take a look through the crystal ball to see what the future has in store…

Congrats! I see cannabis in your future!

That’s right. Cannabis. You might be surprised, maybe even unhappy with these results, but the truth is that there are some pretty neat findings involving cannabis and the endocannabinoid system that may be beneficial to your health.

Cannabidiol (CBD) is an essential component of medical marijuana/cannabis. The CBD industry is growing at exponential rates and will continue to grow. It is your choice if you are going to jump on board with these products that are rapidly growing in popularity.

Cannabis has been used throughout history and has been used for a diverse range of medical purposes. However, although cannabinoids have therapeutic potential, their psychoactive effects have largely limited their use in clinical practice.

Understanding the Crystal Ball

The science described below will help explain the reason for the wide range of effects associated with the endocannabinoid system.

The Cannabinoid Receptor (CB1): CB1 receptors are members of the Gi/Go – linked GPCR family. This means they inhibit voltage sensitive calcium channels and adenylyl cyclase. On the other hand, CB1 receptors regulate the activity of G-protein coupled inwardly rectifying potassium channels and stimulate the MAPK signaling pathway. The figure below shows the activating and inhibiting roles of the CB1 receptor.

Fig. 1

Inhibition: adenylyl cyclase (AC), formation of cyclic adenosine monophosphate (cAMP), activity of protein kinase A (PKA), calcium influx via voltage-gated calcium channels (VGCC).

Activation: MAPK signaling pathway and PI3K/Akt pathway

The CB1 receptors are widely spread throughout the body, thus giving reason to the broad spectrum of physiological roles these receptors can play. With this being said, research has shown the endocannabinoid system to be largely involved in various central neural activities and disorders including appetite, learning and memory, anxiety, depression, schizophrenia, stroke, multiple sclerosis, neurodegeneration, epilepsy, and addiction. The figure below shows the different regions the CB1 receptor is involved in throughout the human body.

Fig. 2

The widespread expression and versatile functions of CB1 receptors support its potential as a drug target for various diseases. However, the undesired effects that arise immediately or later on in life should not be ignored.

The Future is in Your Hands

Nobody can know for sure what the future will bring from these findings, but we can always be optimistic. Ultimately, if individuals are using cannabis for health related reasons and it is improving their quality of life, then there is no point in judgement.

With the growing CBD industry, there are many questions that arise. There are so many different directions to go with the endocannabinoid system that can potentially lead to finding drugs that benefit human health and, of course, improving human health is the ultimate goal. I hope we all go on to live healthy lives. If that life involves drugs targeting the endocannabinoid system, then so be it.  The future is in your hands!

For more information on the research presented on the endocannabinoid system follow this link:  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5877694/

So what’s the big difference between CBD and THC?

There are a number of active ingredients in cannabis aka marijuana and THC is the most prevalent, CBD comes in second. CBD stands for cannabinol which is part of the larger category of phytocannabinoids that make up the complex, naturally occurring compounds in the marijuana plant. CBD seems to be used by everyone from retirees who are struggling with arthritis pain to dogs who have some anxiety while going on car rides. Everyone knows of a success story due to CBD, but how does it really work and why is it different than marijuana?

 

There are naturally occurring receptors in our body specifically made for cannabinoids like CBD and THC and endocannabinoids produced in our body. The most commonly mentioned are CBR1 and CBR2. CB1 is more prevalent in the brain while CB2 is more commonly seen in other peripheral tissues. Two important endocannabinoids produced by our bodies are AEA and 2-AG that will activate CB1 receptors by crossing the membrane and then suppressing neurotransmitter release through the suppression of calcium channels. This is often why people are warry of using THC and marijuana in general as a treatment because there are a larger number of downstream effects that can occur after the activation of these receptors because CBR1 is literally all over our body and the most prevalent GPCR in our brain!

Therefore, people turn to CBD as a treatment option. CBD has a low affinity for these receptors meaning the side effects of its usage are not at worrisome. They likely work through adenosine reuptake on the antagonism of some GPCRs. Below is a figure that lists some receptors or targets in the brain that CBD is known to interact with.

One important interaction to note is that CBD is an agonist of 5-HT which is another name for serotonin which is important in reducing depression and regulating anxiety.

 

In summary, you would have some of the same positive effects on your body if you were to ingest marijuana but using just CBD seems to be a way to reduce the negatives, like the psychoactive component, and still get the beneficial results. However, the research on CBD is somewhat confusing as the federal government is not quite sure how it wants to regulate it yet. Marijuana and therefore THC is still illegal at a federal level and the FDA claims it isn’t sure about the efficacy of CBD even though numerous studies have supported the benefits. Until marijuana is legal, it won’t be an easy subject to study and without studying it, we have no idea the true effects, positive or negative, it can have on our bodies.

https://www.fda.gov/consumers/consumer-updates/what-you-need-know-and-what-were-working-find-out-about-products-containing-cannabis-or-cannabis

https://www.healthline.com/health/mental-health/serotonin#functions

 

Metabolic Syndrome Treatment: Culture, Personal Choice, or Brain Alteration?

Metabolic syndrome is the name for collective disorders caused by overnutrition. Some symptoms associated with metabolic syndrome include:

  • Obesity
  • Insulin resistance
  • Impaired glucose tolerance
  • Dyslipidemia
  • High blood pressure

These symptoms on their own are predictors of development of more serious disorders such as type two diabetes and cardiovascular disease. New research suggests possible mechanisms for development of metabolic syndrome through brain inflammation, especially inflammation of the hypothalamus. Overnutrition activates an inflammatory pathway that alters signaling for leptin and insulin. Leptin and insulin are largely responsible for hunger cues and glucose tolerance. There are several different molecules and pathways impacted by overnutrition and leading to long term changes in the brain. These underlying mechanisms are not yet well understood, though the relationships are rather complex as shown by the image.

Prenatal impacts

When a mother has a high fat diet, consistent with the standard American diet, there can be long term impacts on the child. These changes are due to changes in the way the brain is “wired.” These changes occur when a mother breastfeeds her child and can lead to problems with a child’s eating and an endless cycle of obesity and metabolic syndrome.

Treatment

Treatment of obesity and metabolic disorders is complex and multi-faceted. Treatment possibilities have been explored in mice. The most promising treatment involves inhibition of NFKB/IKKB pathway. This can be accomplished through brain specific deletion of certain transcription factors. Thus far these treatments have only been applied in mice. More common treatments revolve around weight loss. Programs like Weight Watchers and Profile by Sanford are designed to help people navigate diet and nutrition to live healthier lifestyles. Treatment for obesity often requires a reframing of lifestyle choices as well as counseling to treat underling mental illness.

Culture

The United States is ranked #1 in obesity rates across the word at 36.2%. This statistic requires some questioning as other developed nations have much lower rates of obesity. Culture is likely one of the biggest causes of this ranking. According to the USDA, portion sizes are one important aspect to this ranking. In 2000, Americans ate an average of 20% more calories than in 1983. In addition, consumption of fats has increased approximately 45% since 1970. Overconsumption of saturated fats is an important risk factor for triggering inflammatory pathways that lead to metabolic syndrome. One of the most interesting aspects of culture differences is the impact it has on the way people eat in different areas. In the United States, we move fast. We eat fast, work fast, and aim to accomplish as much in the day as possible. In European countries, things move more slowly. People will sit down for hours over a meal while enjoying each other’s company. Government regulations on food in different countries are also vastly different. Countries in Europe often require higher standards and result in food with greater nutrition. Additives are common in food in the United States while they are often outlawed in other countries. Portion sizes are also significantly larger in the US than they are in other countries.

Late Night Television and Obesity

If you have ever had trouble sleeping, you most likely watched late-night television in order to fall asleep.  The commercials televised in the wee hours of the morning often display miracle products, several being diets and weight loss supplements. These products often fail as obesity is a complex disorder caused by several factors. Recent studies have shown a correlation between the inflammation of the hypothalamus and obesity. The cause of this inflammation is still being examined, but one leading cause seems to be the impairment of leptin and insulin signaling.

Understanding the function of the hypothalamus in obesity is crucial for the development of a cure. Early lesion experiments revealed that alteration in the hypothalamic region of the brain resulted in changes in feeding behavior and energy expenditure. Two types of neurons are responsible for this regulation. AgRP neurons control food intake while POMC neurons decrease food intake and increase energy expenditure. Leptin and insulin play major roles in the homeostasis of both neurons. An improper balance of leptin and insulin or ineffective leptin and insulin signaling corresponds to an increase in food consumption and simultaneous decrease in energy expenditure. Studies have shown diets rich in saturated fatty acids cause activation of cytokines and inflammatory pathways, which disrupt leptin and insulin signaling in the hypothalamus. The activation inflammatory pathways lead to transcription of genes like SOCS3, leading to more cytokines and inflammatory signaling. This leads to the chemical hardwiring of the brain to eat more food, making losing weight a massive challenge. The figure  below demonstrates some of the neurochemistry of obesity.

This research does however lead to several possible treatments of obesity. Administering medication that prevents the transcription of inflammatory genes and hinders cytokine and inflammatory pathway signaling are two viable treatment options. Several studies have shown using anti-inflammatory medication such as Tylenol can decrease weight gain.  The simple solution would be to prevent over nutrition or limit saturated fatty acids. However, this may not be as simple as it appears. Currently cheapest and affordable foods, those purchased most frequently by the public, are high in sugars, carbohydrates, and fatty acids. Only individuals with money can afford to purchase fresh fruits and vegetables. This leads to a social and economic dilemma regarding weight gain and obesity. Furthermore, the human body was designed from an evolutionary standpoint. In other words, the ease at which food can be obtained and consumed today, compared to the hunter-gatherer lifestyle, raises the risk for obesity.

The issue of obesity is complex. Studies have shown a correlation between hypothalamus inflammation and the disease. It is hypothesized that inflammation occurs because of an imbalance or impaired signaling of leptin and insulin, leading to inflammatory responses. Treatments of obesity vary in their approach; however, mediation of inflammatory genes and pathways has shown promising results. Factors outside the physiologic domain must also be examined. Several economic and societal facto directly impact obesity. Understanding the complexity of the disease is imperative for one day finding a cure.

Sources

https://moodle.cord.edu/pluginfile.php/798963/mod_resource/content/2/inflammation%20and%20MD%202017.pdf

A Public Health Crisis: The Shocking Relationship Between Type Two Diabetes and Alzheimer’s Disease

Dementia and diabetes are two of the most prevalent health problems facing the world today. Countless resources are spent on treating the symptoms of each, though no clear cause is known for either.

Type two diabetes occurs when blood glucose levels are too high. Blood glucose is the primary way your body gets nutrients from the food you eat. Symptoms of diabetes include:

  • excessive thirst and urination
  • blurred vision
  • increased hunger
  • unexplained weight loss
  • tingling or numbness in hands or feet
  • sores that do not heal

The latter two more commonly occur in prolonged untreated diabetes which often results in greater severity of symptoms.

Risk factors for diabetes include:

  • age 45 or older
  • have a family history of diabetes
  • overweight or obese

One of the most interesting aspects of this relationship is the idea of leptin signaling. Leptin is a hormone released to regulate energy expenditure. In simple terms, leptin tells you to stop eating. Leptin levels are correlated closely with body weight. When diabetes leptin signaling is impaired, people can develop leptin resistance which is often correlated with insulin resistance. Insulin is a growth hormone involved with turning nutrients into useful energy for the body. When the body no longer reacts to insulin, it is called insulin resistance. In the brain, when this happens the impacts can reach the hypothalamus. This body-brain connection has been theorized to be an important link in understanding the relationship between increased risk of Alzheimer’s disease in individuals with type 2 diabetes. First, let’s talk a little bit about what Alzheimer’s disease really is.

Alzheimer’s is a neurodegenerative disease that results in memory loss. It occurs primarily in the older population but a few cases of early onset Alzheimer’s have been reported. There are two main theories behind the cause of Alzheimer’s. Neurofibrillary tangles are one whereas ABO plaques are another. In simple terms, the brain begins to lose some of its primary structure and tissue begins to accumulate before being “cleaned up” by microglia in the brain. This “cleaning up” often results in a loss of a large portion of brain tissue. Symptoms of Alzheimer’s disease include:

  • Memory loss
  • Difficulty solving problems
  • Aggression
  • Confusion
  • Difficulty planning events
  • Personality changes

There is a strong positive correlation between Alzheimer’s and Type two diabetes, though the exact signaling mechanism is still unknown. Release of insulin has been shown to improve longevity and flexibility of neurons through insulin receptors in the brain. Studies also revealed that many individuals with Alzheimer’s had impaired insulin pathways, though the exact correlation between the two diseases is yet to be fully understood. An article aimed to look at this relationship in a comprehensive way, not only studying the relationship, but looking for ways to better treat these diseases and expand the knowledge to the relationship between metabolism and neurobiology. The final message was clear: Each of these diseases needs more research. There is clearly a relationship between the disorders, but understanding just how to use this relationship requires greater research into such devastating health conditions in the world today.

Spam prevention powered by Akismet