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StringJunky

More than half your body is not human

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Human cells make up only 43% of the body's total cell count. The rest are microscopic colonists.

Understanding this hidden half of ourselves - our microbiome - is rapidly transforming understanding of diseases from allergy to Parkinson's.

The field is even asking questions of what it means to be "human" and is leading to new innovative treatments as a result.

"They are essential to your health," says Prof Ruth Ley, the director of the department of microbiome science at the Max Planck Institute, "your body isn't just you".

No matter how well you wash, nearly every nook and cranny of your body is covered in microscopic creatures.

This includes bacteria, viruses, fungi and archaea (organisms originally misclassified as bacteria). The greatest concentration of this microscopic life is in the dark murky depths of our oxygen-deprived bowels. >>>>   http://www.bbc.com/news/health-43674270

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I've read figures of we consist of more than 80% microbes by number but it is a point that I think will change our perception of health, medicine, and how we see our environment. You wouldn't even imagine how many people view antibiotics as a way to get rid of all bacteria in the body. When you point out that they are mostly bacteria and they would die with out them usually brings looks of disbelief. 

This is a great way to move to the concept of how important microbes are on this planet and how the so called "dominant" multicellular creatures could die out in a day and the biggest biological part of our planet wouldn't notice. 

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10 minutes ago, Moontanman said:

I've read figures of we consist of more than 80% microbes by number but it is a point that I think will change our perception of health, medicine, and how we see our environment. You wouldn't even imagine how many people view antibiotics as a way to get rid of all bacteria in the body. When you point out that they are mostly bacteria and they would die with out them usually brings looks of disbelief. 

This is a great way to move to the concept of how important microbes are on this planet and how the so called "dominant" multicellular creatures could die out in a day and the biggest biological part of our planet wouldn't notice. 

There were initial estimates that put bacterial number of cells at ~10x the human cells. The number is closer to even now with current estimates and after defacation chances are good that there the bacterial ratio is lower. One also should also keep in mind that the mass is much lower. Finally, while quite important and having a huge impact, it should also be noted that under controlled (sterile) conditions, regular biological functions do work well in the absence of bacteria. I.e. even while the entire ecosystem may break down, individual functions are not directly mechanistically dependent on bacterial actions.

But yeah, for the most part we are walking habitats.

Edited by CharonY

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This is an excellent topic to discuss. I was just recently grocery shopping and notice all the products advertising themselves as probiotics. Perhaps they have always been around but only recently have I noticed the degree to which they are marketed. I wondered as leaving the grocery store if the lack of nutrients in food from over farmed soil or the popular use of antibiotics were possibly impacting peoples natural microorganism balance which is cause some to seek out supplements. How what we eat, clean our selves with, and lifestyle over all impact the microorganisms our body calls home and vice versa is worth considering. 

To be clear I am not endorsing probiotic use, I understand that people primarily take them for digestive issues, that the microorganisms referenced in the OP exist throughout the body and not merely in one intestines. I only mentioned probiotics because seeing them got me thinking about facets of this topics.

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28 minutes ago, CharonY said:

There were initial estimates that put bacterial number of cells at ~10x the human cells. The number is closer to even now with current estimates and after defacation chances are good that there the bacterial ratio is lower. One also should also keep in mind that the mass is much lower. Finally, while quite important and having a huge impact, it should also be noted that under controlled (sterile) conditions, regular biological functions do work well in the absence of bacteria. I.e. even while the entire ecosystem may break down, individual functions are not directly mechanistically dependent on bacterial actions.

But yeah, for the most part we are walking habitats.

Apparently, blood pressure regulation is quite dependent on gut bacteria producing propionate and acetate which activates olfr78 and gpr41 receptors, which between them keep the pressure within healthy boundaries. I've had this on my bookmarks bar for a while you might interested to read:

https://www.quantamagazine.org/how-bacteria-help-regulate-blood-pressure-20171130/

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We are colony creatures.  Evolution will find a way.  Whatever works.  Perhaps with better and more specific work ups including blood and urine testing we will be amazed how well Mother Nature keeps us running.  Or ... exactly what it is that makes us sick.  Or not sick.

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9 minutes ago, StringJunky said:

Apparently, blood pressure regulation is quite dependent on gut bacteria producing propionate and acetate which activates olfr78 and gpr41 receptors, which between them keep the pressure within healthy boundaries. I've had this on my bookmarks bar for a while you might interested to read:

The connections has to put more carefully. It is not dependent on gut bacteria (which would mean that absence of bacteria would deregulate blood pressure). Rather, they may be on of the factors involved in blood pressure regulation (or, according to the publications, acetate and propionate are and bacteria can modulate the levels). You can also see that in wild-type mice antibiotics treatment had no effect on blood pressure, which further indicates no direct functional dependency (and the effect on the mutant were only modest). 

I.e. interactions with bacteria and the host on many levels are known or at least suspected, but they are not essential in the sense that functions would be fully disrupted.

 

 

Edited by CharonY

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17 minutes ago, CharonY said:

The connections has to put more carefully. It is not dependent on gut bacteria (which would mean that absence of bacteria would deregulate blood pressure). Rather, they may be on of the factors involved in blood pressure regulation (or, according to the publications, acetate and propionate are and bacteria can modulate the levels). You can also see that in wild-type mice antibiotics treatment had no effect on blood pressure, which further indicates no direct functional dependency (and the effect on the mutant were only modest). 

I.e. interactions with bacteria and the host on many levels are known or at least suspected, but they are not essential in the sense that functions would be fully disrupted.

 

 

I almost hate to ask but can you give us a link to the idea of a sterile human being free of all bacteria and still being healthy. I was under the impression that infants are born with bacterial colonies... 

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33 minutes ago, Moontanman said:

I almost hate to ask but can you give us a link to the idea of a sterile human being free of all bacteria and still being healthy. I was under the impression that infants are born with bacterial colonies... 

Rather obviously there are no studies that look at precisely that in a given cohort, as it would ethical very questionable. However, germ-free mice are routinely maintained for infection studies and aside from a sterile environment  they do not require specific adjustments to be viable. Moreover, there are a few studies that showed that germ-free mice were e.g. less likely to become obese (I remember it was a PNAS paper ca. 2007, but forgot the author). Also, perhaps obviously, they do not develop no or reduced inflammatory bowel responses.

In humans the time of sterility (e.g. during high antibiotics treatments) are only transient in which one could collect data. But obviously, they are not lethal. Usually the effects of the AB treatment or the reasons to take them take a greater toll on health than the induced reduction in bacterial load. I doubt that there is good data on long-term effects, though.

 

Edit remembered the paper: link

Edited by CharonY

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47 minutes ago, CharonY said:

The connections has to put more carefully. It is not dependent on gut bacteria (which would mean that absence of bacteria would deregulate blood pressure). Rather, they may be on of the factors involved in blood pressure regulation (or, according to the publications, acetate and propionate are and bacteria can modulate the levels). You can also see that in wild-type mice antibiotics treatment had no effect on blood pressure, which further indicates no direct functional dependency (and the effect on the mutant were only modest). 

I.e. interactions with bacteria and the host on many levels are known or at least suspected, but they are not essential in the sense that functions would be fully disrupted.

 

 

Diet appears plans a critical role. Blood Pressure isn't dependent on bacteria directly but rather a when the amount of bacteria is negatively impacted by a poor diet other cell flourish and the shifted balance has negative impacts. Of course the initiating cause is diet and not bacteria which would imply treating the diet.

Quote

 

The MIT team, working with researchers in Germany, found that in both mice and humans, a high-salt diet shrinks the population of a certain type of beneficial bacteria. As a result, pro-inflammatory immune cells called Th-17 cells grow in number. These immune cells have been linked with high blood pressure, although the exact mechanism of how they contribute to hypertension is not yet known.

https://www.sciencedaily.com/releases/2017/11/171115130859.htm

 

 

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7 minutes ago, Ten oz said:

Diet appears plans a critical role. Blood Pressure isn't dependent on bacteria directly but rather a when the amount of bacteria is negatively impacted by a poor diet other cell flourish and the shifted balance has negative impacts. Of course the initiating cause is diet and not bacteria which would imply treating the diet.

It is a complex interaction. You can think of gut biota as a processing system that alters your food input (and is in turn affected by it), which in turn affects your body. Taking bacteria out, alters the equation, but does not destroy the system, for example. (note: this is obviously ignoring non-metabolite interactions e.g. on inflammation or other cellular interactions).

Edited by CharonY

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7 minutes ago, CharonY said:

It is a complex interaction. You can think of gut biota as a processing system that alters your food input (and is in turn affected by it), which in turn affects your body. Taking bacteria out, alters the equation, but does not destroy the system, for example. (note: this is obviously ignoring non-metabolite interactions e.g. on inflammation or other cellular interactions).

100% true but I think the OP is implying (StringJunky can correct me) is that there could be some corrective benefits to introducing certain microorganisms. 

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1 minute ago, Ten oz said:

100% true but I think the OP is implying (StringJunky can correct me) is that there could be some corrective benefits to introducing certain microorganisms. 

I 100% realize nobody mentioned this, but I couldn't help but think of a girl who took a pill full of tapeworm eggs to try and lose weight.

Not the type of microorganism you want to introduce.

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7 minutes ago, Ten oz said:

100% true but I think the OP is implying (StringJunky can correct me) is that there could be some corrective benefits to introducing certain microorganisms. 

These are not mutually exclusive statements. I am just qualifying the statements that while they have modulating roles (positive or negative) they are not essential for functions such as blood pressure regulation. The benefits of a healthy microbiota, however, is beyond any doubt. 

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10 minutes ago, CharonY said:

These are not mutually exclusive statements. I am just qualifying the statements that while they have modulating roles (positive or negative) they are not essential for functions such as blood pressure regulation. The benefits of a healthy microbiota, however, is beyond any doubt. 

My post was an addendum and not a rebuttal. I think you are 100% correct.

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9 minutes ago, Ten oz said:

My post was an addendum and not a rebuttal. I think you are 100% correct.

Fair enough, I misread the context, apologies for that.

33 minutes ago, Raider5678 said:

I 100% realize nobody mentioned this, but I couldn't help but think of a girl who took a pill full of tapeworm eggs to try and lose weight.

Not the type of microorganism you want to introduce.

The use of helminths for weight loss is not approved and its current promotion in certain circles is IMO irresponsible. However, there are experimental therapies involving helminths to address autoimmune diseases.

Edited by CharonY

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9 hours ago, CharonY said:

There were initial estimates that put bacterial number of cells at ~10x the human cells. The number is closer to even now with current estimates and after defacation chances are good that there the bacterial ratio is lower. One also should also keep in mind that the mass is much lower. Finally, while quite important and having a huge impact, it should also be noted that under controlled (sterile) conditions, regular biological functions do work well in the absence of bacteria. I.e. even while the entire ecosystem may break down, individual functions are not directly mechanistically dependent on bacterial actions.

But yeah, for the most part we are walking habitats.

Mitochondria? Chloroplasts in plants? The integration of micro-organisms can be more than superficial and essentially chemically-interdependent.

Quote

Conclusion

Microbes sustain life on this planet because of their myriad associations and biogeochemical processes. Nonetheless, their roles are not necessarily irreproducible. When you next hear someone claim that we cannot live without microorganisms, it would be appropriate to ask them to qualify the statement. Would we still be able to eat and digest food? Yes. Would life be extinguished in the absence of Bacteria and Archaea or in a world without any microbes? Not immediately, not all life, and potentially not for a long time.

In short, we argue that humans could get by without microbes just fine, for a few days.* Although the quality of life on this planet would become incomprehensibly bad, life as an entity would endure.

* If we do include mitochondria and chloroplasts as Bacteria, as we should, then the impact would be immediate—most eukaryotes would be dead in a minute.   http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.1002020

 

Edited by StringJunky

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9 hours ago, StringJunky said:

Mitochondria? Chloroplasts in plants? The integration of micro-organisms can be more than superficial and essentially chemically-interdependent.

This is not really an integration into human (or eukaryotic) functions. Archaea and bacteria are the precursor of the eukaryotic cell. I.e. you are talking about evolutionary history. As such the statement of the authors make no sense. If we exclude prokaryotes, we would not have eukaryotes to begin with.

None of which relates to the functions of the microbiome that colonizes us. You cannot meaningfully conflate these aspects (other than to make a metastory of bacterial importance overall, which is just trivially true).

 

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2 minutes ago, CharonY said:

This is not really an integration into human (or eukaryotic) functions. Archaea and bacteria are the precursor of the eukaryotic cell. I.e. you are talking about evolutionary history. As such the statement of the authors make no sense. If we exclude prokaryotes, we would not have eukaryotes to begin with.

None of which relates to the functions of the microbiome that colonizes us. You cannot meaningfully conflate these aspects (other than to make a metastory of bacterial importance overall, which is just trivially true).

 

I can try. :D 

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Well.... let me rephrase that :)

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A fascinating thought.

Isn't it strange how science continues to confirm the ideas of the leading science fiction writers?

One can't help but wonder how they knew.

 

 

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1 hour ago, JacobsLadder said:

A fascinating thought.

Isn't it strange how science continues to confirm the ideas of the leading science fiction writers?

One can't help but wonder how they knew.

 

 

The brightest SF writers will be on top of the latest thinking and extrapolate a novel from that.

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3 minutes ago, StringJunky said:

The brightest SF writers will be on top of the latest thinking and extrapolate a novel from that.

And everyone forgets all the sci-fi that unsuccessfully predicted the future: aka most sci-fi.

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5 minutes ago, Prometheus said:

And everyone forgets all the sci-fi that unsuccessfully predicted the future: aka most sci-fi.

Like gamblers only brag about their winnings.

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