I wrote this as a piece for one of my relatives who is a doctor and for his friends as a casual read. Because of this reason, this doesn't have references in line. Check it out below and let me know what you think!
When Dr. Janardhanan asked me to
write an article for doctors, I started wondering what I could possibly talk
about that appeals to the most knowledgeable community on the face of the
planet. What could I tell about biology to great doctors that years of real
experience with real patients hasn’t taught them? However, as a PhD student in
basic biology, I thought I could write about a topic that fascinates me and has
taken the biology research world by storm. There is a constant debate about
whether we (the government/taxpayers) should spend valuable money on basic
research (‘basic research’ is research about answering questions about how
living things work, as opposed to ‘translational’ targeted research about
finding out cure for diseases). This debate reminds me of a quote by mountaineer
Gregory Mallory who made the first attempt (although, in vain) to climb Mt.
Everest. When asked “why do you want to climb Mt. Everest”, he famously
replied, “because it is there!” In my opinion, that curiosity about how living
things work is sufficient reason to do basic research – ‘because it is there’.
But I will also point out that basic biological research is much more than
research to satisfy curiosity – researching on a topic ‘because it is there’. There
have been so many serendipitous discoveries that emerged from basic science
research that mankind has benefited from – some of the popular ones are the
discovery of X-rays, the identification of insulin, development of pap smear
test and the identification of penicillin. Thus, there is no doubt that
research in basic biology will help us in the long run to solve many of the
human problems/diseases.
Human microbiome – the hot
topic in basic biology research today:
Keeping with the theme of
emphasizing basic research, this article is about a hot topic in basic biology
research today. I would like throw light on a few astonishing findings about
the human microbiome and how the microbiome influences the functioning of the
human body in a surprisingly huge way. The ‘human microbiome’ denotes the vast
variety of micro-organisms that inhabit the human body, often in a
non-pathogenic way. It includes bacteria, fungi, archaea, viruses and even some
eukaryotic micro-organisms. They inhabit many areas of the human body including
the skin, conjunctiva, saliva, oral mucosa and majorly, the gut/digestive
(gastro-intestinal) tract.
The human microbiome is
overwhelming and immense:
The human intestine is home to
roughly about 100 trillion microorganisms! That number is so huge that it is 10
times more than the total number of human cells. To reiterate – there are more microbes in just our
intestine than there are human cells in the whole body!!! The discovery of
the huge number of microbes and the immense diversity of these microbes brought
up many questions. We have only begun to scratch the surface about finding out
what all these things do.
We have advanced so much in
biology these days that we want to identify the molecular/genetic basis of
everything. Extending that to the human microbiome, one can ask many questions
- how many/what genes do these microbes encode? What effects do these genes and
their products cause in the human body? To put the immensity of these questions
in perspective, the gut microbes encode around a hundred times more genes as
there are in the humans. The human genes themselves are so complex and have so
many functions - now imagine how many functions hundred times as many genes can
have! Simply mind-blowing!
The diversity in the human
microbiome:
An important fact about the microbiome
is that each person and body part has a unique composition of microbes. With
the advent of cutting-edge gene-sequencing technologies, we are able to
identify what microbes are present in a human being’s body. The ‘human
microbiome project’ set out to identify and catalog the microbes of our body.
Strikingly, they found that the composition of the microbiome varies from
individual to individual. And even more strikingly, they found that the
composition of microbiome may be potentially different in healthy versus
diseased individuals! What more, even though a different species of microbe
might occupy one healthy individual’s gut from another healthy individual’s
gut, they can perform similar functions. As long any microbe carries out the
function, the human being is fine – healthy and happy. The minute there is no microbe
there doing that function, is when problem starts.
From mood to mosquitoes – the
microbiome influences practically everything our body does:
We have begun to study what
processes and functions of the human body these microbes influence. I have
highlighted a few astonishing facts about how human well-being and health is
affected by the composition and function of the microbiome.
·
Consider H.pylori.
We have always thought of it as a ‘bad’ microbe because it causes gastric
ulcer. But, a study found that H.pylori
positive persons have a lower risk of childhood asthma and allergies. Because
of the bacteria’s role in modulating the ghrelin hormone, eliminating H.pylori to protect against ulcers could
contribute to early obesity and type-2 diabetes instead.
·
A study found that the composition of the human
skin microbiome affects how ‘attractive’ a person is to the malarial
mosquitoes.
·
The gut microbes break down some sugars that our
body’s enzymes cannot digest.
·
The gut bacteria form a natural immune barrier
and have many protective roles in guarding against other infections. Some good
bacteria compete against bad pathogenic bacteria and protect us! In addition,
when inflammation breaks the delicate balance between the host (human body) and
the good microbes, it can cause serious effects, even colorectal cancer.
·
Cystic fibrosis patients exhibit unusual
respiratory bacteria, in other words, the composition of the respiratory tract
microbiome differs in healthy versus diseased individuals.
·
Microbiome can affect our mood! (maybe that is
why they are called ‘gut’ feelings). Changing the gut microbes alters
risk-taking ability and sociability in mice. When researchers gave probiotics
to anxious mice, the mice showed reduced anxiety and decreased stress hormones.
So what does all this mean to
doctors?
Creatively, many people like to
describe the human microbiome as a separate, understudied organ that pretty
much dictates everything in the human body. Others have taken to describing our
body as a ‘superorganism’ – a distinct group of organisms that includes human
cells, rather than thinking of it as a main human body occupied by these small,
insignificant microbes. However we describe the human microbiome, we have come
to a point when we cannot deny that they play crucial roles in the functioning
of the human body.
Gone are the days when we thought
of bacteria, viruses, fungi and other microbes just as villains of human
health. Bacteria are bad because they cause diseases, right? That’s why we use
Lifebuoy soaps and anti-bacterial everything in the modern world, right?
Wrong!! Sure, there is a whole world of pathogenic microbes out there. But as
we unravel functions of the human microbiome and understand how much they help
the ‘normal’ functioning and well-being of human body, one begins to wonder if
the bad blame we’ve been putting on these microbes all these years is true,
after all.
All being said, one has to agree
that research in this direction is still in very preliminary stages. We have a
long way to go in understanding what the implications of the human microbiome
are. Nevertheless, it is evident that in some form or the other, the microbiome
contributes to normal well-being of humans. When the delicate balance between
humans and these microbes is lost, it can result in disease.
Knowing about human microbiome
has huge implications in the field of medicine – especially in a world where
there are so many antibiotics, probiotics and what not. Antibiotics are
miraculous drugs and have saved numerous lives. But in the light of the
microbiome, we need to look at other side-effects of antibiotics – not just in
causing antibiotic resistances, but also interfering with the balance between
the microbial populations and human cells and the potential effects it can
have. Wiping out all the microbes or even a specific species using antibiotics
might result in more effects than just curing a disease. It might alter the
microbiome in a way that we don’t understand yet.
To sum up, your microbes make you
who you are – from your mood to that stupid mosquito that keeps biting you,
your microbes could be the reason!
