Helicobacter pylori genome found in the stomach of a 5300-year-old Ice man

Oetzi the Iceman

Oetzi the Iceman was found in 1991 in the high Oetzal Alps that span Italy and Austria.  He is a mummy who gained popularity in the scientific community because of how well he was preserved and thus the potential to provide a glimpse into Europe’s past (he is thought to be around 5,300 years old, alive in the European Copper Age).  Many studies have examined his diet, health, and genetics, but recently researchers were able to discover identify and examine his stomach and intestines.  Biopsy samples were collected and PCR analysis determined the presence of the gram-negative bacteria Helicobacter pylori. 

H. pylori can be found in about half of the world’s population, and while research has pointed to the harmful effects of this bacterial strain, recent work has supported that the bacteria can in fact protect against some illness such as acid reflux and asthma.  However, extensive characterizing Oetzi Iceman’s H. pylori could also shed light on ancient human migration patterns.  Specifically, modern strains of H. pylori are assigned to distinct populations based on their geographical heritage, originating from either ancestral Asian populations (AE1) or hybrids between North Africa and Europe (AE2). 

Comparative whole genome analysis showed that Oetzi Iceman’s H. pylori genome has highest similarity to three apAsia2 H. pylori genomes from India, and further high-resolution analysis of ancestral motifs revealed a co-ancestral matrix, showing that H. pylori shares ancestry with Indian strains but also with most European strains.  Low levels of H. pylori ancestry was shared with the AE2 ancestry, which was interesting to scientists as it suggests AE2 introgression into Europe after the Copper Age.  This was later than what has been proposed previously by the scientific community.  Ultimately, these findings showed that Oetzi Iceman had H. pylori with strong AE1 genetic Asian origins, suggesting that the AE2 bacteria from African heritage began arriving after the Copper Age of European civilization.  

A new drug from the microbiome may someday treat acne

Optical microscope image of Propionibacterium acnes, the bacteria that causes acne.

One of the most prevalent diseases caused by our microbiome is acne.  As many people know, those little red pimples are caused by an immune response to the otherwise normal skin bacterium, Propionibacterium acnes.  Many treatments for acne use broad spectrum oral antibiotics to eliminate the bacteria, which we at the AMI discourage for reasons we have blogged about before.  New research suggests that another common microbiome bacterium, Helicobacter pylori, may have utility in fighting P. acnes and preventing acne.

Research recently published by the British Journal of Dermatology investigated the effects of using a peptide made from the microbiome bacterium Helicobacter pylori to reduce levels of P. acnes and to decrease the immune response to these bacteria.  The researchers discovered that the peptide, known as HPA3NT3, was quite effective in destroying various strains of P. acnes.  Moreover, the treatment decreased the production of interleukin-8, which is responsible for inflammation.  Finally, the researchers showed the peptide did not destroy the skin of mice nor elicit an immune response on its own.

While the study did not use humans, which would have been ideal, it showed a potential new treatment for acne.  In addition, it is another example of using natural products from the microbiome to develop new drugs, and in this case treat a common microbiome disease.  Acne is among the top 10 most common diseases in the world, and while not usually medically dangerous it does have negative consequences, so we are glad that this microbiome disease is getting some attention.

The Blaser hypothesis: The microbiome is programmed to kill us

Editors note: I understand that the title to this blog is a bit sensationalist, but if ever a microbiome paper called for a sensationalist headline, this is the one.

Microbiome scientist Marty Blaser (and member of our scientific advisory board) and mathematician Glenn Webb published a remarkable hypothesis last week in Mbio .  The hypothesis states that the microbiome is ‘programmed’ to protect us in our youth and reproductive ages, and then kill us in our old age.

First we must consider the enormous influence the microbiome has on our health, both positive and negative, and that we have only explored the tip of the iceberg as to the true impact the microbiome has.  Then, we must remember that the microbiome has evolved with us for hundreds of millions of years, from mother to child, and that from the microbiome’s perspective, humans are just a vehicle for reproduction.   Finally, we must acknowledge that the microbiome is subject to the same evolutionary principles as any organism or community, and that the laws of nature dictate that it attempts to fundamentally organize itself so as to optimize its population.  Once we accept these three things we can investigate how the microbiome could exert its influence on humans so as to improve its population.

A mathematical analysis was performed that showed the most prospering populations of humans, and by extent our microbiomes, occur when young children survive through reproductive ages, but then die shortly after reproductive age.  Long lasting, post-reproductive humans can actually diminish the overall population because they drain certain resources.  With that in mind it is not a stretch to consider that the microbiome may be dictating this type of population structure.  That is, the microbiome prospers when it kills its host (us) shortly after reproductive age, and that it is evolutionarily ‘programmed’ to do just that.  This type of population structure occurs in other animals, and the human age structure is unique in the animal kingdom.  Humans are pre-reproductive (pre-pubescent) for a longer time than most animals, and then are post-reproductive (senescent) for a much longer time than other animals.    

The authors go on to give examples of how bacteria may be dictating the ideal age structure (protecting children and killing senescent humans).  We know of many bacteria that exist in children that are protective but then decrease in population into adulthood.  In addition there are examples of bacteria, like Helicobacter pylori, that confer protection early in life, but then the very same bacteria can become pathogenic and cause disease later in life.  Other bacteria which cause acute infections that kill their host seem only to strike older adults.  Finally, the inflammation caused by the microbiome gets worse into old age.  In fact, many of the frailties associated with old age can be traced to the microbiome. 

It is an interesting hypothesis, and one that the reader should ponder.  While it likely can’t ever be proven, this hypothesis supports the idea that it’s a bacterial world, and we are just living in it.