BioQuakes

AP Biology class blog for discussing current research in Biology

Tag: asthma

We Didn’t Start the Fire…Gut Microbes Did.

Many scientists have hypothesized that infants’ gut microbiota could influence the development of their immune system. Recently, a test led by Drs. Christine C. Johnson at the Henry Ford Health System in Detroit and Susan Lynch at the University of California, San Francisco, but this theory to test. Specifically, they set out to examine the relationship between an infant’s gut microbiota and their relative risk of atopy and asthma. The researchers inspected the composition of gut microbes in stool samples from almost 300 infants—all part of a diverse study group born in and around Detroit between 2003 and 2007—by means of examining sequence variation within ribosomal RNA. Ultimately, the team found that the infants could be divided into 3 separate groups, each with distinct bacterial and fungal gut microbiota.

When blood samples obtained from the infants at 2 years of age were tested for sensitivity to allergens, the 3 microbiota groups had significantly different risks for allergen sensitivity. The “high-risk” microbiota group had a relatively lower abundance of certain bacteria and a higher level of some fungi, and was more likely to be diagnosed with asthma at 4 years of age. This seeming link between gut microbiota and allergy and asthma was also manifested when other factors associated with allergic disease—such as breastfeeding—were controlled. Moreover, the researchers found that the high-risk group had a distinct set of metabolites that lacked anti-inflammatory fatty acids and breast milk-derived oligosaccharides that were found in children in the low-risk microbiota group, increasing vulnerability to inflammation.

File:500px photo (56342660).jpeg

Neonatal gut microbiota play a huge role in health and disease (Credit: Eric Atkins)

The researchers also mixed immune cells from healthy adult donors in solutions containing metabolites extracted from the infant’s stool samples. The high-risk group’s metabolite samples increased the amount of allergy-promoting immune cells interleukin-4, a cell-signaling protein associated with allergies, and also reduced T-regulatory cells, an essential group of immune cells that suppress allergic responses. This reduction in T-regulatory cells was also spurred by a lipid that the team identified, called 12,13-DiHOME, that was found at high levels in the high-risk group. Discussing this finding, Lynch expressed to The Scientist, “That for me is incredibly exciting as it suggests that microbial-associated metabolites in the neonatal gut may represent an important driver of early-life immune cell phenotypes associated with disease development in childhood.”

The team plans to conduct a similar study that will focus on environmental factors and how they may affect the development of the gut microbiota. According to Lynch, “Understanding the basis of human-microbial development may prove critical to unraveling the basis of allergy and asthma and to developing preventative therapeutic strategies.”

A Possible Way to Prevent Asthma in Infants

Did you know that asthma in infant boys may soon be able to be prevented? Infant boys whose mother’s have asthma are at a higher risk of developing asthma due to genetics. However, according to a study published by the University of Alberta in Canada, the structure of the gut microbiome may also play a role in the development of asthma in these boys. Microbiomes are the bacteria that live in human digestive tracts. The research team, led by epidemiologist Anita Kozyrskyj, studied the characteristics of the gut microbiome in 1000 infant boys born to mothers with asthma.

The team discovered that these boys were one-third as likely to have certain characteristics in their gut microbiome when they were 3-4 months old. The boys had a significantly less amount of Lactobacillus microbes. This evidence suggests that maternal asthma can be associated with the lack of Lactobacillus. The team believes that this discovery could lead to modifying the gut microbiome in these infants to reduce their risk of developing asthma.

The team started this research because they wanted to study the sex-based differences between boys and girls born to mothers with asthma. The gut bacteria on infant girls was affected differently. Girls have more bacteria than boys that maintain a mucus barrier and protect the gut cells. The team believes that this barrier protects the girls from developing asthma as babies, but are more prone to developing it during puberty.

Asthma is a breathing disease that affects many people. It is interesting to learn about how this sometimes deadly disease may be able to be prevented in infants. Although there it is not definite that this can be prevented, it is fascinating to read about this possibility. For more information on gut microbiomes, click here and here. Based on this research, do you think that scientists will be able to find a way to modify the gut bacteria?

 

Infants’ Feces Says a Lot about the Gut Microbiome

Who knew studying babies’ poop can actually lead to amazing discoveries about childbirth, breastfeeding, antibiotics, allergies, and asthma?

That’s exactly what scientists Fredrik Bäckhed and Jovanna Dahlgren at the University of Gothenburg, Sweden, and Wang Jun at the Beijing Genomics Institute-Shenzhen, China recently learned when they conducted a study analyzing feces from 98 Swedish infants.

But before we get into the details of the study, let’s get down the basics first. What exactly is the gut microbiome?

Gut microbiome is the name given to the population of microbiota organisms that live in the human intestine. These microorganisms are unique, not only because there are trillions of them but also because they have milliions of genes, and can function as a person’s identity card (much like a fingerprint or a strand of hair).

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(Source: https://en.wikipedia.org/wiki/Fecal_bacteriotherapy#/media/File:E_coli_at_10000x,_original.jpg)

Recently there’s been a lot of buzz in the science world about the gut microbiome because it seems as though it plays various crucial functions, and this study is just one of many. The Swedish and Chinese scientists discovered a few ways in how the gut microbiome affects childbirth, breastfeeding, and development.

There are two ways to give birth: vaginally or via a cesarean section, or C-section. Comparing the feces collected from babies born vaginally and from babies born via C-section, scientists discovered that the feces from the latter contains a significantly less similar microbiome to the microbiome of their mothers.

They also determined that nutrition during the early stages of an infant’s life is a core factor in the development of the gut microbiome.

Our findings surprisingly demonstrated that cessation of breastfeeding, rather than introduction of solid foods, is the major driver in the development of an adult-like microbiota

-Fredrik Bäckhed, lead study author

Bacteria rely on the mother’s milk to grow. Once the bacteria’s access to that milk stops, the bacteria stops growing. In its place, adult-like microorganisms emerge.

In addition, the gut microbiome acts as nutrients and vitamins to the infant’s growth and development, and gives aid to important processes such as making amino acids.

The study also critiques the amount of antibiotics given to babies when they’re born. There’s speculation that the baby’s gut microbiome is negatively impacted by the overabundance and overexposure of antibiotics. Besides the obvious risk of antibiotic resistance, one hypothesis is that when exposed to antibiotics early on, the gut microbiome loses important bacteria that helps immune cells mature. This is believed to be the reason why allergies and asthma are now widely prevalent.

Though this study is just a preliminary, it’s amazing just how big of an effect the gut microbiome has on us, and how much new research is coming out.

Want to learn more about the gut microbiome? Check out other sources about the microbiome, such as it’s relationship on the brain, and how it can change the brain’s function, how it can help reduce weight, and junk food’s negative impact on it, and make sure to comment below!

 

 

Original Article

Asthma From The Gut

Asthma is a a disease without a cure. Unfortunately, it is spreading rapidly throughout the world.  With asthma, a person’s lungs do not function normally, and the lungs are a key part of the immune system.Asthma is related to a hyperactive immune system, a system that is gut-centric. Since it can not be cured, the best we can currently do is try to identify it’s causes. This can be very challenging and scientists do not know much about the bacteria inside of us. Being gut-centric implies a direct relationship between the gut microbiome and the immune system.

Asthma Inhaler

Image courtesy of NIAID on Flickr

Recently, a team of scientists proved this direct relationship. Their study discovered that the abundance of FLVR bacterium in a baby’s gut can affect their likelihood of being diagnosed with asthma. The study showed how Canadian children with low levels of FLVR in their feces when they were three months old proved much more likely to get asthma. By the time they reach age one most kids have the same levels of FLVR, this shows how key the timing is. The study then provided mice with extra FLVR, and tried to induce asthma. But, instead of getting inflamed lungs, the mice continued to breathe normally. This displays a potential solution. Scientists now believe that in those first three months of life, FLVR is necessary to properly train the immune system.

I chose to do this study because asthma is a disease that rapidly affects more and more people. The study, discovering a new cause of asthma holds promise. This suggests a possible future cure for asthma. If scientists can use antibiotics to perhaps enhance the levels of FLVR in the early days of children’s lives, perhaps asthma can be cured. This study of the different types of bacteria in the immune system is especially interesting due to our unit on the structure of different types of cells. Learning about the greater, medical application of this particular type of bacteria is especially fascinating. Please feel free to comment below with any thoughts or questions you have regarding this topic.

The original article can be found here. 

How Intestinal Microbiota Could Prevent Asthma

There are trillions of microbiota living in the average human intestine.  These microorganisms have formed a mutualistic relationship with humans and take on a number of functions including digestion, vitamin production, and the prevention of harmful bacteria growth.  In addition to these essential roles, new research shows that four types of these organisms may prevent asthma

Bacteria

 

The four types of bacteria are Faecalibacterium, Lachnospira, Veillonella, and Rothia.  Currently, some scientists think that these bacteria, FLVR for short, help prevent asthma by creating chemical byproducts.  These byproducts are thought to help train the immune system to attack harmful germs and to prevent inflamation.  Having these microorganisms is essential for the development of children. It is possible that the absence of the bacteria can lead to many health problems for people, including asthma.  Stuart Turvey, a pediatric immunologist at the University of British Columbia and a co-author of the study, thinks that being exposed to the FLVR microorganisms at very young ages is essential for preventing asthma and has said “Having the right bacteria in place at the right time is really important, especially in those early months of life.”  Despite their research, scientists do not know much about why the immune system possibly malfunctions when it is not exposed to the bacteria.  However they do know that the immune system becomes “confused” and creates inflammation in the lungs.

These new findings on asthma could possibly explain why asthma’s prevalence has tripled to quadrupled in first world countries in the past 30 years.  The advanced medical knowledge and technology in these countries could possibly be creating an over sterilized world.  Due to more and more doctors treating common sicknesses with antibiotics, human intestines are starting to become too clean and they lack the essential microorganisms including FLVR.  The absence of of these FLVR bacteria is likely to put more people at risk of developing asthma.  One study showed that many Canadian school children had very low levels of FLVR bacteria, putting them at high risk of developing asthma. Another study performed on mice strengthens the viewpoint that these bacteria prevent asthma.  The study examined new born mice by exposing some to FLVR and leaving the rest without the bacteria.  The results showed that the mice exposed to the FLVR at very young ages had much lower rates of inflammation in the airways.

Original Article

Epigenetics for Asthmatics


In a recent study, a group of scientists obtained findings that could lead to a new approach to treating allergies. Instead of looking at the genes of their test subjects, they looked at something “above” the genome. Here we reach the field of Epigenetics.
Let us first define “Epigenetics” as the study on the activity and regulation of genes. In the world of Epigenetics, one can think of the epigenome as the on-off switch for the expression of genes. In terms of the study lead by Professors William Cookson and Miriam Moffatt, they focus on genes that trigger Asthma in patients. As Asthma cannot be ‘cured’, is there a way to shut down the genes that cause it?

The research team searched for a correlation between Asthma-causing antibodies and low methylation levels. Methylation is the process by which a methyl group attaches to certain genes in order to regulate their activity. Scientists already know that people with asthma have higher levels of an antibody called “Immunoglobin E” (IgE). This antibody is involved in triggering the symptoms of asthma. It is already known that genes responsible for producing IgE are hyperactive in asthma patients. The question became whether methylation had something to do with it. So to answer this question, the researchers obtained volunteers with asthma, but with varying IgE levels. The group found significant results surrounding lower levels of methylation with the patients that had higher levels of IgE than those with lower levels of IgE in their blood. This suggests that the lower methyl levels on certain genes evokes an overactivity of IgE producing genes.

After reading the article myself, I wonder if asthma patients could find ways to have higher methyl levels in their body to shut down the overactive IgE-producing genes. Perhaps they could consume a methyl rich diet? I guess it’s not that simple. Further research should obviously go into epigenetics, since I feel it is a newly discovered field. Anyways, here are the head scientists reactions to the experiments:

Professor Moffatt: “The genes we identified represent new potential drug targets for allergic diseases as well as biomarkers that may predict which patients will respond to existing expensive therapies.”

Professor Cookson: “Our pioneering approach, using epigenetics, allowed us to obtain insights that we weren’t able to get from traditional genetics. It isn’t just the genetic code that can influence disease and DNA sequencing can only take you so far. Our study shows that modifications on top of the DNA that control how genes are read may be even more important.”

This article (and the entire study of Epigenetics) shows how scientific knowledge and thought is always changing. Before recent research showing a link between one’s living environment and their genetic activity came along, scientists widely believed that one only passes down inherited genes to their offspring. This potentially makes scientists now look twice at Lamarck and Darwin’s theories of evolution. Due to the new research conducted on Epigenetics, Lamarck’s (originally rejected) theory of how an animal’s environment will affect that animal’s offspring can now be regarded in a whole new light.

Original Article: http://www.sciencedaily.com/releases/2015/02/150218073057.htm

Further Reading: http://www.extremetech.com/extreme/180963-lamarcks-revenge-the-epigenetics-revolution-may-redeem-one-of-darwins-oldest-rivals

A Breath of Fresh Air: Epigenetic Studies Help Asthmatics

Asthma and allergies affect many people worldwide. Up until recently, treatments for both asthma and allergies were administered without an appropriate prediction of responses; However, this is about to change. In a recent study conducted by scientists at Imperial College London, “30 new genes that predispose people to allergies and asthma” were found. The discovery of these genes means that new treatments for allergies are possible and more accurate predictions for current treatment responses will be available.

Photo by Author

Photo by Author

By observing the epigenetic changes, ones that influence gene activity- not genetic code, the scientists were able to identify genes which are linked to triggering allergic responses. Such genes regulate specific antibodies. Genes become inactive through methylation: the attachment of methyl molecules to DNA. The scientists studied white blood cells of families with asthma to see if methylation levels in specific genomic locations were associated with levels of an antibody in the blood. Immunoglobin E (IgE) is the antibody studied in the case. The antibody IgE was known prior to this study, but the genes which activities it regulates were not. After monitoring the IgE levels in the blood, researchers saw a strong correlation between IgE and low methylation at 36 places in 34 genes. These genes are overstimulated in asthmatics, thus the production of IgE is increased, contributing to asthma symptoms. In expanding the investigation, researchers came to believe that IgE-involved genes may activate eosinophils, a type of white blood cell which in asthmatics promotes airway inflammation by gathering and releasing chemicals in airways/lungs. Researchers believed that these genes, and their ability to activate eosinophils, then cause the most damage. In order to test this, researchers isolated eosinophils from the blood of subjects and demonstrated that all 34 genes have high activity levels in asthmatics with high IgE levels. Thanks to the findings of new activation signals, patients can avoid high costs and ineffective “treatment-trials” because we’ll be able to predict responses to treatments with more accuracy. Professors Cookson and Moffatt, the leaders of the investigation, give credit to epigenetics for allowing them to make a breakthrough in discovering new potential drug targets for allergies and asthma and sharpening the accuracy of treatment-response predictions. Professor Cookson explained that, “the genetic code that can influence disease and DNA sequencing can only take you so far. Our study shows that modifications on top of the DNA that control how genes are read may be even more important.”

As someone who suffers from allergic asthma, I find it intriguing how the disease-triggering genes aren’t inactive, thus leading to poor lung function, but rather they are overstimulated. Our genes’ ability to regulate disease-triggering antibody activity is amazing. With new studies like this one, we can see that the solution to proper activity regulation is in epigenetic changes, rather than the broad expectations of “our genes”.  This just goes to show that epigenetics is helping us make strides in the ever-changing world of medicine. It should be interesting to see how epigenetic medical-solutions, the current gold mine of Biological research, evolve in the near future.

 

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