Month: June 2017

If I was the head of a funding agency (like the National Institute of Health) in which my job is to look at proposals for research projects and decide what projects to award funding to, the research that I would be most excited about fundings as it related to learning more about microbial influences on human health is Helicobacter Pylori (H.pylori) effects. As I learned from the first few weeks of this term about H.pylori and its effects on human health due to diseases such as gastritis, atherosclerotic disease, and development of gastric cancer as well. It led me to H.pylori eradication to protect human from these diseases above. However, when I worked on my final paper, I found the controversial information about H.pylori in  Gastroesophageal reflux disease (GERD), Inflammatory bowel diseases (IBD), allergy, and asthma. Also, in the article “What are the consequences of the disappearing human microbiota?”, the authors talked about the disappearance of H.pylori  which is salutary for human in order to prevent gastric cancer, but the oesophageal reflux, Barrett’s esophagus and adenocarcinoma increase. I raised a question whether people should have H.pylori  eradication for all H.pylori infections cases and what conditions people should or should not have H.pylori  eradication.

In the project, we are likely to learn how H.pylori affects human health related to Gastroesophageal reflux disease (GERD), Inflammatory bowel diseases (IBD), allergy, and asthma. I would think that the project will provide results which H.pylori infectious patients who have or do not have increasing effects of Gastroesophageal reflux disease (GERD), Inflammatory bowel diseases (IBD), allergy, or asthma after having H.pylori eradication. Also, what are differences in genomes or other factors which contributes to increasing of these diseases in the different group of patients who can be separated by ages, living conditions, and geography? The findings from the project which we likely to learn to play important role in future healthcare decisions because people will know which H.pylori infectious cases they should have H.pylori eradication and which one is not so as to prevent from gastric cancers. Also, for people who have Gastroesophageal reflux disease (GERD), Inflammatory bowel diseases (IBD), allergy, or asthma may have new treatments by using H.pylori bacteria. People can find categories for H.pylori infectious patients related to H.pylori eradication. Besides, the usage of antibiotic to stop and kill H.pylori would have the new approach to use in the right way.

Source: Blaser, M. J., & Falkow, S. 2009. What are the consequences of the disappearing human microbiota?. Nature Reviews Microbiology, 7(12), 887-894.

                The non-infectious diseases that I can think of are influenced by microorganisms are brain cancers, diabetes, heart disease, celiac disease, stomach cancer, Alzheimer disease, and Parkinson’s disease.                  

               Refer back to my writing #1, I was not sure what infectious diseases and noninfectious diseases are. I found that I understood wrong that all infectious disease would communicable. In the writing #14,  I was sure about my non-infectious diseases, and while I wrote down these diseases, I also thought of the relationship between microbe and human health. For example, IBD, including UC and CD is related to gut microbiota population. I think that the most important topics that I will take away with me once I have completed the course are the different microbes, as well as the diversity of microbes, plays the important role that can be beneficial or have negative effects on human health. There are many topics associated with the roles of microbes which the people need further studies to discover. People should learn how to improve the human gut microbiota which is significantly important. I would learn and earn more knowledge about microbes and try to find information for controversial and information which researchers are trying to explain through their studies during this course in the next microbiology classes.

 

Microbial communities in the body could influence brain and mental health states through signaling pathway. The production of the neurotransmitter serotonin in the cells in the gut which may affect the signaling in the brain via the systemic interaction between the gut and the brain. In the study of a biologics, Hsiao, the research examined how certain metabolites from gut microbes are related to body’s serotonin ( 5-hydroxytryptamine, 5-HT) production. The microbiota plays a significant role in regulating host 5-HT. The indigenous spore- forming bacteria from the mouse and human microbiota leads 5-HT biosynthesis which affects host physiology. The gut microbiota modulates the peripheral serotonin level of the host [1]. Besides, the intestinal microbiome can prompt immune cells to produce cytokine which influences the brain via signaling of other cell types. Another example is the production of butyrate of the microbes which is correlated with the activity of cells in the blood-brain permeability. The gut microbes break down the carbohydrates into short-chain fatty acids such as fatty acid butyrates which enhance the blood-brain barrier by tightening connections between cells [2].

Besides, the brain and mental states may also influence on the gut microbiota through changes in behaviors or release of neurotransmitter, hormones, and steroid. For example, the release of catecholamines and norepinephrine during stress into the GI may cause the dysregulation of the gut-brain axis via the changes in GI motility, the mucus secretion, and epithelial cells. These might lead to different gut diseases. Also, in the early maturity life in the animal, the stress increased the level of corticosterone production and inflammatory cytokines. The stress situation may cause the decrease of gut function related to changes in the microbial community and gut diversities. Moreover, the development of postinfectious irritable bowel syndrome is correlated to stress-related psychosocial factions which could be somatization, hypochondriasis, and neuroticism [3].

Overall, microbes and mental health states are linked together. From the people with ASD have IBD and other gastrointestinal problems. There are different abundances of microbial communities in ASD patients in the relationship with gastrointestinal diseases. In the case study of John Rodakis, his son showed improvement in the gut and behavioral autism after using antibiotic treatments. This suggested that the researchers would need to conduct more studies about different members of gut microbiota which are associated with autism and neurological states [4]. From the lecture this week, there are proposals about influences of microbes such as bipolar disorder, obsessive-compulsive disorder, post-traumatic stress disorder, schizophrenia. However, there are also many skepticisms about these proposals which make this topic become controversial. I think that whether microbial communities in the body could influence brain and mental health states or brain and mental health states could influence microbial communities in the body should depend on specific patient cases.

Yano, J. M., Yu, K., Donaldson, G. P., Shastri, G. G., Ann, P., Ma, L., … & Hsiao, E. Y. 2015. Indigenous bacteria from the gut microbiota regulate host serotonin biosynthesis. Cell, 161(2), 264-276.

Smith, P. 2015. The tantalizing links between gut microbes and the brain. Nature.526: 312-314

Thakur AK, Shakya A, Husain GM, Emerald M, Kumar V. 2014. Gut-Microbiota and Mental Health: Current and Future Perspectives. J Pharmacol Clin Toxicol 2(1):1016.

Rodakis, J. 2015. An n= 1 case report of a child with autism improving on antibiotics and a father’s quest to understand what it may mean. Microbial ecology in health and disease, 26.

 

1. Can experiments detect differences that matter?

                     This question is important when researchers carry out experiments. In this part, the author first talked about profiling a microbiome which is able to categorize at the level of phyla, species or genes. The disadvantage is from criterion which researchers used the different ratio of bacteria to distinguish microbes. For example, if an experiment was used to characterize animal communities, based on the ratio between an aviary of 100 birds and 25 snails and the ratio between an aquarium with 8 fish and 2 squids,  both an aviary of 100 birds and 25 snails were identical with an aquarium with 8 fish and 2 squids. However, it was not right because of the differences in stains in the genes which each species contain. Later, the modern technology provides a better way for distinction when they were able to study more genes in a sample. Nevertheless, if the networks are not characterized well, the outcome to any specific object is hard. In addition, the ability to identify functional differences in related genes play the important role to understand the genes or networks. Also, genomes are poorly understood with clues which can be true or false. Therefore, an experiment can detect differences or not play a significant role for researchers to understand fully about the subjects, especially topic related to genomes.

2. Does the study show causation or correlation?

                       In this part, the author discusses how an experiment was conducted in two directions, inverse and reverse directions in order to know if the study showed causation or just correlation. It’s so important to question when interpreting scientific literature. For example a study about gut microbiomes and diet in a 2012 article which was proposed a causal relationship after conducting a study between the gut microbiomes of old people living in care homes and old people living in the community. Though the data and proposal were fit together, the reverse causality, the potential for poor health to alter the gut microbiome, was not investigated. The less active immune system and differences in the digestion of frailer people could lead changes in the microbiome. In this case, the conclusion about the causal relationship was not correct. Thus, I think that this question helps researchers to have the overview and come with an appropriate proposal.

3. What is the mechanism?

                   This question helps researchers to have a deeper understanding of the subjects in their study. When there was a correlation which can contain a causal relationship also. However, the researchers do not know what makes the relationships. With the modern technology, the researchers are able to identify functional elements, different taxa, and specific characteristics. The experiment can be done to define actions of elements in microbiome related to the biochemical activity. This contributes to making a study become more convincing.

4. How much do experiments reflect reality?

                    This question focuses on examination the reflection of experiments to the reality. For example, the study about gut flora and weight gain. The researchers did the experiment on germ-free mice which did not represent the natural state of animals and do not have healthy owing. Thus, the study did not include the responses in animals with flouring microbiomes related to different adaption between mice and their microbiomes and human. Thus, the result may not generalize. This question provides researchers about their subject choices and evaluation if the result from their study is suitable and able to convince people in public including general readers and scientists.

5. Could anything else explain the results?

                This question made me think of variables in a study. It’s necessary for researchers to think that there are other potential factors which could affect the results of their study and the way to analyze the data, make generate the hypotheses and evaluate the conclusion. For example, bacteria affects human but whether or not there are possible factors contributing to these effects. It is important to know about contributing factors in a study in order to make sure the results are not affected by these factors before coming to a conclusion.

               ** Overall, these five questions help the researchers to avoid hype. I think that question about the mechanism is the most helpful when discussing the controversy topic. As I understand, the controversy topic is from the disagreements among researchers on a topic. The researchers carry out different studies on the same topic, but they may have different results which may lead to opposite conclusions. For example, my final essay focuses on a question whether or not Helicobacter pylori eradication should be applied for GERD, Inflammatory bowel diseases (IBD), and allergy and asthma patients which researchers had different results from their studies to argue about this topic. The unclear part which was hard to explain the mechanism to support.

Source: Hanage, W. P. 2014. Microbiome science needs a healthy dose of scepticism. Nature, 512(7514), 247.