Tagged: interleukin

Why You Need Vitamin C: A Guide to the Most Well Known Vitamin

cvitamin2

Hello The Weekly Paper readers! Thank you all for making last week’s post the most successful ever. This blog is finally gaining some serious traction and I want you all to know I truly appreciate the support.

This week’s question comes from my dad, who asks “Can you explain to me why we need vitamin C? Why do they say you need it when you’re sick?”

Vitamin C is known officially as L-ascorbic acid. This molecule is a dietary requirement and a chronic deficiency of vitamin C produces the famous disease “scurvy.” Principally, vitamin C has two main functions: enzyme co-factor and antioxidant.

In the body, vitamin C is used mostly as a co-factor in certain enzymes. A co-factor is a separate, non-protein component of an enzyme that is required for its function. Specifically, vitamin C acts as a reducing agent, which is a refers to its ability to reduce, or donate electrons, to other compounds and thus become oxidized (lose electrons) in the process. Within the realm of enzymes which utilize vitamin C, it acts as the electron donator (reducing agent) that returns the metal ions, which actually do the catalytic enzyme reactions, back to their proper reduced state. If the metal ions are allowed to be permanently oxidized, the enzyme then becomes useless and the reaction for which it is responsible no longer occurs. Put a much simpler way, oxidized = rusted, so the vitamin C prevents the metal ions from becoming rusted over and losing function.

So now that we understand that vitamin C allows metal ions in certain enzymes to function normally, let’s explore what enzymes actually use this mechanism. Primarily, vitamin C is used by enzymes involved in collagen, carnitine, norepinephrine, dopamine, and peptide hormone creation, as well as participating in tyrosine metabolism. As you might imagine, this is a fairly diverse group of enzymes; we still don’t fully understand the extent of vitamin C’s value across all relevant enzymes nor all of the mechanisms involved for each enzyme.

Of particular note, vitamin C plays an essential role in collagen formation. Without it, you cannot properly heal wounds and connective tissues can become seriously weakened. For example, the initial symptoms of scurvy largely stem from reduced collagen synthesis capacity. These include bleeding (due to compromised blood vessels), gum disease, poor wound healing, and bone issues, among others. As such, anyone having surgery should discuss with their surgeon the need to take vitamin C supplements before and after the procedure.

Vitamin C also has activity as an antioxidant, using its role as an easy donator of electrons to neutralize free radical (single electron) species on its own. Sadly, no one has comprehensively studied what impact this has on human health. But, it remains that vitamin C can act as an antioxidant and, as you are probably aware, reducing oxidative damage is a very important element of maintaining many aspects of our health.

Insofar as the immune system/treatment of disease is concerned, vitamin C’s role is much less clear cut. Clearly, its biological role is diverse and thus it could have a much greater role than we currently know. However, as of now what has been seen in the lab is extremely diverse and difficult to translate into clinical practice. Studies have shown vitamin C to reduce virus activity, suppress tumors, and regulate the immune system during infection (by influencing interleukin activity). But clearly, plenty of people take vitamin C regularly and still get sick. So it is hard to say, as of now, whether or not supplementing vitamin C for this purpose is really helpful to the immune system or is just merely a complement to an otherwise normal body response in healthy individuals.

The bottom line is, no matter what get your daily vitamin C by any means necessary. You can supplement, but even better you should get it from healthy foods that contain many other great nutrients such as broccoli, peppers, and kale. You’ll be happy you did.

Thank you for the question, dad! As always, if you have a question you’d like answered here, feel free to submit to directly at the link above.

Till next time, one love.

Justin

Sources:

http://www-ncbi-nlm-nih-gov.libproxy.usc.edu/pubmed/9350472

http://www-ncbi-nlm-nih-gov.libproxy.usc.edu/pubmed/914459

http://www.sciencedirect.com.libproxy.usc.edu/science/article/pii/S0022030293776171

http://jnci.oxfordjournals.org.libproxy.usc.edu/content/83/8/547.short

http://www.sciencedirect.com.libproxy.usc.edu/science/article/pii/S0165242798001202

http://ajcn.nutrition.org.libproxy.usc.edu/content/33/1/71.short

http://link.springer.com.libproxy.usc.edu/chapter/10.1007/978-1-4615-9200-6_1

http://www.nlm.nih.gov/medlineplus/ency/article/000355.htm

http://www.healthaliciousness.com/articles/vitamin-C.php

The Enemy Inside: Rhumatoid arthritis and Autoimmunity

RA Ulnar Deviation

This week’s question comes from Cory, who asks, “I have been reading your blog posts, they are so great. I would love it you wrote one on autoimmune diseases, specifically Rheumatoid Arthritis. I have RA and the lack of information about it is astounding. The number of times I have been told that I have the same thing as Shaq (who has osteoarthritis) is unreal.” Well, Cory, I agree that there is widespread misinformation and misunderstanding about autoimmune diseases, including RA. Even worse, people tend to associate these diseases solely with the elderly, which could not be further from the truth. Let’s explore how autoimmunity works, highlight RA as an example. and efforts to treat it and other autoimmune diseases.

Autoimmunity, as you might infer from the name, is a type of disease where the immune system starts attacking the body’s own tissues. It can occur in just about every tissue the body has, though some types are much rarer than others. As we explored briefly in a previous blog, the body’s cells have surface markers that declare them as “self,” or part of the organism. When the body normally produces immune cells, it has mechanisms in place to prevent self-attacking cells from maturing and becoming part of the immune system. This is known as immunological tolerance The thymus is the organ where T-cells (hence the “T”) mature and autoimmune T cells are found and normally destroyed. B cells, which do not have a particular organ to mature within, undergo a process known as receptor editing during their maturation. Receptor editing tests the immature B cells against self antigens (identifying proteins) in the bone marrow and those that react strongly undergo apoptosis (cell death) to prevent autoimmunity under normal conditions. T cells undergo a similar process within the thymus. This process is not fool proof, as some low-levels of autoimmunity exist throughout the body, but on the whole that low level has minimal impact on normal functioning. So how, then, does this transition from normal to an autoimmune disease state occur?

The answer to this is unfortunately incredibly complicated and not well established in any one direction. I will do my best to summarize three of the prevailing theories, however this is going to be far from an exhaustive list. These are also not exclusive explanations; autoimmunity may be caused by one or a combination of these or other factors.

  • Loss of immunological tolerance: As noted above, immunological tolerance is the process by which B and T cells are exposed during development to self antigens and self antigen-reacting cells are destroyed. When this process is disturbed, autoimmune cells can avoid destruction and enter circulation. This can also occur if a certain type of self antigen not normally presented in the thymus or bone marrow is newly introduced into the blood by trauma or surgery or is absent all together from these maturation areas by genetic mutation.
  • Reduced regulatory T cell activity: Regulatory T cells are responsible for down-throttling the activity of T cells. Its job is two fold: modulate T cell activity back to normal after a pathogen has been eliminated and maintain immunological tolerance. The exact mechanism for this process is unknown. It is theorized that the reduced activity can either stem from suppression (by the use of other signaling molecules that keep them away) or by loss of sensitivity to their regulatory signal. It is thought that these issues may be genetic in nature, stemming from mutations expressed within the thymus that affect T cell function around the body.
  • Cross-reactive antigens: Certain pathogens can present antigens that are similar enough to a particular tissue’s self antigen to prompt a response against both. For example, syphilis and Klebsiella infections can cause autoimmunity against the mitochondria (anti-cardiolipin) and spine (ankylosing spondylitis), respectively.

Now that we have an understanding of how these autoimmune cells can get out and attack, let’s explore rheumatoid arthritis (RA) specifically within the context of our understanding. RA involves autoimmunity against the articular (joint) cartilage and synovial membranes (where the lubricating fluid for the joint comes from). This disease causes progressive joint damage, scarring, and eventually fusion of the bones and complete loss of joint function. It is systemic, which means that it can effect any part of the body, though it is most commonly recognized by its effects on the hands. It also has a host of related effects on the blood vessels, neurological system, heart, kidneys, lungs, and eyes. RA has a particularly strong genetic component, though a significant component also can be attributed to smoking or particular viral infections.

The mechanism by which RA operates is not definitively proven, but it is thought to involve inappropriate B cell-T cell interaction. Under normal circumstances, T cells recruit B cells to the site of an infection by use of messaging molecules called cytokines. There are many different types of cytokines, each with a specific message. The one of particular value is called tumor necrosis factor-alpha, or TNF-a. TNF-a is secreted by, among other cell types, T cells to promote many of the symptoms of infection, such as local inflammation, fever, etc. Combined with interleukin-1 (Il-1) and interleukin-6 (Il-6), which are signaling molecules from T cells that prompt local B cell maturation, these represent the most basic model of interaction between B cells and T cells. TNF-a has been shown to be a major regulator of Il-1, with increased TNF-a contributing to increased systemic levels of Il-1. It is thought that inappropriately increased TNF-a and Il-1 are responsible for setting in motion the inflammatory processes associated with RA. This TNF-a and interleukin activity is also thought to possibly kick off activation of similar immunological processes across the body, far removed from the original site. This model might explain the diverse side reactions present in RA across a variety of tissues that can’t possibly be explained by a simple loss of immunological tolerance. Other interleukins have significant roles (specifically Il-6, Il-15, and Il-17), however the effects of TNF-a and Il-1 on the progression of RA have been fairly well established in the literature.

So, as you may have already concluded, TNF-a and Il-1 present ripe targets for attack to prevent the process at the source. Drugs against TNF-a currently represent the mainline treatment method for treating RA. Molecules called monoclonal antibodies, which are essentially B cell antibodies against a particular molecule, that specially target TNF-a were created to do just this. Other similar antibody-based fusion protein bio-technologies have also been developed, with similar effects. Unfortunately, attacking this widespread and multi-faceted molecule can have negative effects on the immune system. Because it is so important to normal immune function, suppression of TNF-a can lead to undesirable side effects such as cancer, increased rates of infections, and congestive heart failure. So these drugs represent a powerful weapon in the fight against RA and other autoimmune diseases, however the benefit must be weighed with their strong side effects.

It is possible that the future will involve stimulating the body’s own regulatory mechanisms to present development of autoimmune conditions without inhibiting immune response. Il-2 has been shown to naturally decrease TNF-a production, which represents a potentially fruitful route for future research. However, the activity of TNF-a is only one mechanism. Many other autoimmune diseases are unfortunately not quite so well understood and must be treated with strong drugs like corticosteroids to induce broad immune suppression. Less damaging drugs can be used to control symptoms (ex. retinoids such as acitretin to reduce skin lesions in psoriasis) in lieu of immuno-modulating (changing the immune system) therapies like steroids and monoclonal antibodies.

It is clear that the induction of autoimmune disease is incredibly complicated and involves a variety of very complex cellular signally pathways we are only beginning to understand. Due to this, it will likely be many years before we can begin to attack these diseases without collateral damage to the wider immune system. But, luckily for those who suffer from RA, these anti-TNF-a drugs represent a quantum leap forward in the battle and may herald a new era of drugs capable of even more effectively modulating an immune system gone wrong.

Hope this helps, Cory! Thank you for the question. As always, everyone and anyone is welcome to submit a question.

Till next time, namaste.

Justin

Sources:

http://www.mayoclinic.com/health/rheumatoid-arthritis/DS00020

http://www.arthritis.org/conditions-treatments/disease-center/rheumatoid-arthritis/

http://rheumatology.oxfordjournals.org/content/43/suppl_3/iii2.abstract

http://www.ncbi.nlm.nih.gov/pubmed/8717520

http://www.ncbi.nlm.nih.gov/pubmed/8391952

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1782226/

http://pathmicro.med.sc.edu/ghaffar/tolerance2000.htm

http://www.ncbi.nlm.nih.gov/books/NBK2396/

http://www.jrheum.com/subscribers/02/65/10.html

http://www.ncbi.nlm.nih.gov/pubmed/9018238

http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm109340.htm