SCIENCE & TECH

Decoding the 2015 Nobel Prize in Physiology or Medicine: The Layman version

The 2015 Nobel Prize in Physiology or Medicine was announced today (5th October 2015) and was awarded one half jointly to William C. Campbell and Satoshi Ōmura for their discoveries concerning a novel therapy against infections caused by roundworm parasites and the other half to Youyou Tu for her discoveries concerning a novel therapy against Malaria (1).

The objective of this write-up is to provide a Layman’s version of the Science done by these three scientists and its significance in our daily life. Anyone with college level understanding of Biology will find this article too simple and mundane, but I believe there are a lot more people out there who has no biology background whatsoever. Understanding the magnitude by which these research benefits humanity will make us appreciate and take seriously  the field of basic science, which unfortunately many find alien and irrelevant.

First, all three were awarded the Nobel prize for their research done in developing drug therapies  (medicines) used to treat diseases caused by parasites (think of Tapeworm, hookworm so on). Though uncommon in developed countries, diseases caused by parasites (like Malaria, Filariasis) are a major cause of death in the developing and underdeveloped nations and the work done by these three helped the scientific community to develop marketable drugs which can treat these infectious diseases. William C. Campbell and Satoshi Ōmura discovered a new drug, Avermectin, used to treat River Blindness and Lymphatic Filariasis, while  Youyou Tu discovered Artemisinin, a drug that has much reduced the mortality rates for patients suffering from Malaria (1).

Though we call the medicines which we buy from Medical stores as drugs,  the word “drug” in the context here means the chemical compound present in these medicines which makes the “medicine to work”. So, when the Nobel Committee says “these three developed drugs…”, it means these Scientists developed the chemical compound which helps treat the disease and not the last drug which your doctor prescribes. Keep in mind that years of research including animal/human tests are done on these “compounds” after they are discovered by various drug companies as well as research laboratories  before it finally reaches out to the public as a “medicine”. So, the work done by William C. Campbell and Satoshi Ōmura together as well as work done by Youyou Tu paved way for developing the final version of the drugs!

Let us now see how William C. Campbell and Satoshi Ōmura are connected, in the sense, why they were awarded the prize together (Both of them gets 25 % of the prize money while Youyou Tu gets 50 %). Satoshi Ōmura, as his website says, is a world leader in Bioorganic Chemistry,  who has devised many novel methods for isolating, culturing and screening microorganisms, discovering more than 470 compounds, many of them unique (2). One such compound he has isolated is the Avermectin, a naturally occurring compound generated by fermentation (A process which convert sugar to other products) by Streptomyces avermitilis ( A bacteria) . Now, William C. Campbell , an expert in parasite biology working in the USA, acquired Ōmura’s Streptomyces cultures and explored their efficacy (1).  Campbell showed that a component from one of the cultures was remarkably efficient against parasites in domestic and farm animals (1).  The bioactive agent was purified and named Avermectin, which was subsequently chemically modified to a more effective compound called Ivermectin (1).  Ivermectin was later tested in humans with parasitic infections and effectively killed parasite larvae 1.  Collectively, Ōmura and Campbell’s contributions led to the discovery of a new class of drugs with extraordinary efficacy against parasitic diseases (1). So, it is like, Omura discovered the compound and Campbell found it’s proper use and hence the collective award!

Like Satoshi Ōmura, who isolated Avermectin,  Youyou Tu isolated the compound Artemisinin from the plant Artemisia annua (Remember, Avermectin is  produced by bacteria). Tu, herself proved later that this compound was highly effective against the Malaria parasite, both in infected animals and in humans (1).  It is interesting to know that Youyou succeeded in identifying the right compound by reading about herbal medicines in ancient literature!

Finally let us see how both of these compounds work. Ivermectin, the derivative of Avermectin “stimulates excessive release of neurotransmitters in the peripheral nervous system of parasites (3)“. Neurotransmitters are a group of chemical compounds which plays a very important role in communication within the nervous system and high fluctuation in the levels of these neurotransmitters can be deadly (even for us!) The drug meddles with the biologic pathways that control neurotransmitter release in parasites, leading to excessive neurotransmitter build up, in turn paralyzing the parasite. Artemisinin, the anti-malarial drug works by acting directly on Parasite mitochondria (4). Mitochondria (known as “powerhouse” of a cell) is one of the most vital cell-organelle in a cell and it is shown that artemisinin causes “mitochondrial depolarization” which means nothing but mitochondrial damage which can lead to series of “bad things” happening to the parasite, ultimately killing it.

As the Nobel Prize website puts it, discoveries of Avermectin and Artemisinin have fundamentally changed the treatment of parasitic diseases.   Avermectin is highly effective against a range of parasites, has limited side effects and is freely available across the globe (1) .  Artemisinin is used in all Malaria-ridden parts of the world. When used in combination therapy, it is estimated to reduce mortality from Malaria by more than 20% overall and by more than 30% in children. For Africa alone, this means that more than 100 000 lives are saved each year (1).

In summary, these two compounds alone help us save millions of lives across the globe at basically no cost! There are thousands of drug compounds discovered, used in as many medicines (or even more),  but the sheer number of patients using these 2 drugs, cost effectiveness and the fact that “these are “drugs for the poor” would have been the decisive factor in the Nobel committee choosing these 3 scientists  for this year’s Nobel prize in Medicine.

 References:

  1. http://www.nobelprize.org/nobel_prizes/medicine/laureates/2015/press.pdf
  2. http://www.satoshi-omura.info/
  3. http://dermnetnz.org/treatments/ivermectin.html
  4. http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0009582

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