Gut flora- Suspects of interest in the cause and treatment of type 1 and 2 diabetes

I previously discussed how an unhealthy gut can cause tissue inflammation and ultimately lead to obesity. Nevertheless, gut microbiota have further reaching effects than just weight gain. According to recent studies, the biological makeup of your gut could play a significant role in the onset of both type 1 and type 2 diabetes. 
The cause of type  1 and 2 diabetes is not explicitly known. Type 1 diabetes is not preventable and often runs in families, but isn't related to lifestyle choices (such as diet and exercise). Type 2 diabetes is preventable and closely related to genetics, high blood pressure, and obesity. However, research suggests that another factor in diabetes could be related to the health and biological makeup of your gastrointestinal tract. 

In the development of type 1 diabetes, there are three crucial factors relating to gut health that interact closely with one another. The microbiota found in the gut (specifically those that trigger inflammation)  play an important role in the formation of autoimmune diabetes. Moreover, it is believed that the interaction of gut bacteria and the mucosal immune system in postnatal development may have long-term effects and implication for the formation of type 1 diabetes later in life (Vaarala, et al. 2008). Another factor is the degree of permeability of the intestinal wall. Those suffering from type 1 diabetes have a more permeable gut than those without the disease. Low levels of a special tight junction protein known as "claudin" cause an increased permeability in intestines of individuals with type 1 diabetes. This extreme permeability not only leads to increase exposure to sugar, but to other dietary antigens that trigger an immune response. Furthermore, an altered mucosal immune system could be a significant factor in failure for the body to form tolerance which consequently lead to autoimmune responses (Vaarala, et al. 2008).


A study investigating the relationship between gut flora and the development of type 2 diabetes discovered that gut flora may play a role in increasing the permeability of the intestinal walls. Mice fed a high fat diet which induced type 2 diabetes showed an increase in adherence of bacteria to the membrane of the intestines. Ultimately, these bacteria are able to move through the membrane and into the adipose tissue (stored fat) as well as the blood (Amar, et al. 2011).  However, with a probiotic treatment (Bifidobacterium animalis subsp. lactis 420), membrane adherence diminished along with the translocation of bacteria to fat cells and blood. Utilizing such probiotics may prove helpful in controlling diet induced diabetes, as inflammation was reversed in this particular study (Amar, et al. 2011).


References:

Amar, J., Chabo, C., Waget, A., Klopp, P., Vachoux, C., Bermúdez-Humarán, L. G., Smirnova, N., Bergé, M., Sulpice, T., Lahtinen, S., Ouwehand, A., Langella, P., Rautonen, N., Sansonetti, P. J. and Burcelin, R. (2011), Intestinal mucosal adherence and translocation of commensal bacteria at the early onset of type 2 diabetes: molecular mechanisms and probiotic treatment. EMBO Mol Med, 3: 559–572. doi: 10.1002/emmm.201100159

Vaarala, O., Atkinson, M. A., & Neu, J. (2008). The "Perfect Storm" for Type 1 Diabetes: The Complex Interplay Between Intestinal Microbiota, Gut Permeability, and Mucosal Immunity.Diabetes, 57(10), 2555-2562.

Diet, exercise, and... helpful microbiotas?

In my previous post I briefly discussed the many different ways in which gut flora contribute to our health and wellbeing. Today I will be discussing how gut flora relate to a major health risk that effects countless individuals across a wide array of demographics. With easy access to cheap and fattening foods, little time to exercise, and in some cases, unfavourable genetics; many industrialized and developing countries suffer from high obesity rates. However, despite common belief, obesity is not simply related to diet and lifestyle choices. Environmental factors, genetics, and systemic and adipose tissue inflammation also contribute to weight gain (Kotzampassi, et al. 2014).

The 100 trillion cells of microbiota found in the human gut play an important role in energy harvest and body weight. This concoction of bacteria is extremely diverse amongst humans; although, Firmicutes and Bacteroidetes (Actinobacteria) are dominant types. In fact, studies suggest that a gut composition including more Firmicutes and less Bacteroidetes (and overall less microbiota diversity) is linked to slower metabolic pathways and increased fat storage (Kotzampassi, et al. 2014). Furthermore, Bifidobacterium spp. of the phylum Actinobacteria, may have anti-inflammatory effects leading to a leaner host.  Nevertheless, the bacteria falling under the phylum Firmicutes, Staphylococcus aureus, may lead to inflammatory effects, increasing the risk of obesity. In summary, such findings suggest that manipulation of gut bacteria could be a fundamental practice in preventing the onset of obesity (Kotzampassi, et al. 2014).

Reference:

Katerina Kotzampassi, Evangelos J. Giamarellos-Bourboulis, and George Stavrou, “Obesity as a Consequence of Gut Bacteria and Diet Interactions,” ISRN Obesity, vol. 2014, Article ID 651895, 8 pages, 2014. doi:10.1155/2014/651895

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"Good" Bacteria or "Bad" Bacteria?

        In my previous blog, I outlined the systems of the body in which gut flora play an essential role in development and function. Today, I begin to look at how gut flora influence the developmental function of the immune system; specifically the mucosal immune system.
      The mucosal immune system is the portion of the immune system that protects mucous membranes throughout an organism's body. The membrane of the gut has the largest mucosal surface area in the body, which is continually exposed to microbes found in food as well as naturally occurring gut flora (Hanson, 1998). The mucosal immune system must be very precise when deciding whether or not a microorganism is 'good' or 'bad' for the body; there are so many helpful gut bacteria in our intestines as well as potentially harmful  invaders!
     Small proteins released by cells in the gut, called Cytokines, facilitate interactions between antibodies and T cells (Science Dictionary). Some Cytokines boost the response of the immune system, while others cause immunological tolerance, or no immune response (Hanson, 1998). Our immune system develops tolerance to the gut flora in our intestines; however, when the mucosal immune system fails to distinguish the difference between harmful and helpful (breaks tolerance to gut flora), it can lead to autoimmune diseases such as inflammatory bowel disease (Hanson, 1998). Nevertheless, the manipulation of micro flora may lead to promising therapeutic treatments (O'Hara & Shanahan, 2006).


Citations:

Brian, P. (n.d.). Science Dictionary - Glossary of Terms & Scientific Definitions. Science Dictionary. Retrieved March 13, 2014, from http://sciencedictionary.org/

Hanson, L.A. (1998). Immune effects of the normal gut flora. Monatsschrift Kinderheilkunde, 146(S1), S2-S6.

O'Hara, A. M., & Shanahan, F. (2006). The Gut Flora As A Forgotten Organ. EMBO Reports, 7(7), 688-693.

Have a gut feeling? Microorganisms may have more influence than you think...

     I decided to abandon my previous endeavour and instead chose to write about a new topic that both interests me and is more related to my field of study; psychology. From the motherhood of cows to the microbiology of the human gut; I will now be exploring how evolutionary biology plays a role in a much different realm of functioning and survival.

      Many of us know that the human body serves as a great host for a variety of microorganisms; some good and some less desirable. Generally these microorganisms that inhabit our bodies are only brought to our attention with the onset of a common cold (viral infection) or perhaps even strep throat (bacterial infection). New research suggests that microorganisms, specifically those living in our gut, deserve more consideration. In fact, the microorganisms brewing in your gut may have more influence in your body than you think.

     Recent research has revealed that microorganisms inhabiting our gut may play a vital role in the regulation of a variety of psychological processes such as mood, pain, cognition, and may even be related to obesity. This opens the door for new therapeutic possibilities from those suffering from stress-related central nervous system disorders, an arena where the need for new medical innovations is high (RD et al. 2014). One might wonder how gut flora play a role in the central nervous system; how could organisms in the intestines effect our brain and spinal cord? Simply put, microbiota play a major role in the maturation of crucial systems that then, in turn, effect the central nervous system. More specifically, microorganisms of the intestine impact the development of the immune and endocrine system, which ultimately effect the signalling and programming of the central nervous system (RD et al. 2014). But wait, there’s more! Other studies have even suggested a relationship exists between gut flora and the rate of aging (Heintz et al. 2014).

      Let’s recap; gut microbiota can influence the regulation of mood, pain, cognitive processes, weight gain, and even the rate of aging. These gut flora certainly do play an important role in the human body! I will further elaborate on these concepts in later blogs as I continue my journey in exploring the power of microorganisms.

References:

Heintz, C. & Mair, W. 2014. You are what you host: microbiome modulation of the aging process. Cell 156: 408-411.

Moloney, R. D., Desbonnet, L., Clarke, G., Dinan, T. G. & Cryan, J. F. 2014. The microbiome: stress, health and disease. Mammalian Genome 25: 49-74.

Does Mom have a favourite?

        Growing up with siblings can be a challenge for many reasons; competing for resources (in human terms, often food and toys), mother's attention, and perhaps the turmoil of having that pesky younger brother is a challenge in itself. Consequently, many of us growing up with a sibling have had the novel idea that perhaps we, obviously the superior child, were Mom or Dad's favourite. Recently, scientific studies of various class Mammalia animals have lead researchers to believe that some mothers of the animal kingdom do in fact 'have a favourite'. More specifically, studies have indicated that some mothers variate  their investment in offspring (Hinde, 2014).
      How might an animal, like a  cow, give advantage to one offspring over another? Well, it turns out cows have different synthesis capacities for milk based on their offspring's sex, and mother cows tend to favour their female offspring (Hinde, 2014). Moreover, if you're a cow, it pays off to have an older sister. Cows that rear a female offspring first not only produce significantly more milk for that offspring, but the following offspring (Hinde, 2014).
      However, not all mothers favour daughters. In fact, Pronghorns (Antilocapra Americana) tend to favour their male offspring; yet size variation was still present in same-sex litters (Drik, 2013). Why might this be? Variation between offspring in a given litter increased reproductive  success, specifically in a short time period after birth (4-6 days). In fact, litters that had size variation suffered from less sequential mortalities, where a predator would kill one offspring and then come back for seconds (Dirk, 2013).
     Perhaps some of these variations seem downright unfair, but ultimately, it's important to look through an objective lens at these 'favouritisms'.  These bias investments we find in nature serve to promote the overall evolutionary fitness of the species and thus are essential practices of future generations.

If you'd like more information, please take a look at these articles below:

Hinde, K., Carpenter A. J., Clay, J. S. & Bradford, B. J. 2014. Holseins favour heifers, not bulls: biased milk production programmed during pregnancy as a function of fetal sex. PLoS One 9: e86169.

Van Vuren, D. H., Bray, M. P. & Heltzel, J. M. 2013. Differential investment in twin offspring by female pronghorns (Antilocapra americana). Journal of Mammalogy 94: 155-161.