BODY BY DARWIN

The father of the science of evolutionary medicine, Randolph (Randy) Nesse, has a favorite aphorism: “Medicine without evolution is like engineering without physics.” In the same way that it would be impossible to imagine building the Rosetta spacecraft, sending it 300 million miles to rendezvous with Comet 67P, and successfully deploying the Philae lander, chock-full with sampling instruments, without physics and specifically Newtonian mechanics, it proves similarly impossible, for instance, to get to the root of the horrifying scourge of Alzheimer's disease unless we ask deep and fundamental questions, informed by evolution, about what the alleged poisonous plaques of beta-amyloid protein are doing in the brain in the first place. Is amyloid pure pathology or does it have an vital evolved function in the brain? In this sense, Nesse has frequently claimed that the value of evolution to medicine is that it while it may lead directly to changes in medical practice or indeed to new therapies, more fundamentally its value lies in explaining why things are as they are. That is why Nesse argues that evolutionary biology should be the foundation and cornerstone for medicine as it should be for all biology. This book is an attempt to put yet more flesh on the bones of Nesse’s idea that evolution is the “physics” of medicine. I describe the evolutionary background to seven areas of human disease that are causing deep contemporary medical concern to explain why they exist in the first place—why things are how they are - and how evolution might help us to combat them. I hope it will leave readers with a new respect for evolution as the prime mover for the structure and function of human bodies, even if it does, on occasions, cause them to break down and drives us into ER!

Each chapter is built around the sometimes harrowing but always inspiring personal stories of people trapped in the disease process in question. Each chapter provides an evolutionary explanation for why the disease has come about, and each chapter shows how medical researchers, using powerful insights gained from thinking about disease in an evolution-informed way, are charting our way out of it.

ABSENT FRIENDS
How a modern version of the hygiene hypothesis - called the "old friends" hypothesis - explains why the Western world is riddled with allergic and autoimmune diseases, and what we can do about it.
A FINE ROMANCE
How evolutionary theory explains why the battle between the different selfish genetic interests of mothers, fathers, and fetuses causes low fertility and can lead to diseases of pregnancy like recurrent pregnancy loss, preeclampsia and gestational diabetes.
THE DOWNSIDE OF UPRIGHT
What is the relationship between the fact that we have evolved to walk upright - our bipedalism - and a range of orthopedic illnesses?
DIY EYE
Creationists have always used the example of the "irreducible complexity" of the human eye as the bedrock of their argument that God designed the human body, not evolution. Modern developmental biology, however, not only strongly rebuts creationism but explains the astonishing secret of how the recipe for eyes actually unfolds from within the developing eye itself, not from external influences, and is leading to cures for eye diseases like retinitis pigmentosa and macular degeneration.
HOPEFUL MONSTERS
How does cancer evolve so remorselessly towards malignancy that it is proving almost impossible to cure? Cancer evolution can be so extreme and drastic it is forcing us to re-write the rules of evolution by resuscitating a heresy from the 1940s.
A PROBLEM WITH THE PLUMBING
Why are coronary arteries evolution's answer to feeding our powerful, muscular hearts with the food and oxygen they need and how has this led to the continuing pandemic of coronary heart disease?
THREE SCORE YEARS - AND THEN?
Research into curing Alzheimer's disease has become hopelessly bogged down and billions of dollars have been wasted trying to turn the "amyloid hypothesis" into therapy. Can we use evolutionary thought to better explain why dementia comes about in a way that might lead to fresh hope for a cure?

READ ON DOWN TO ENTER MY BLOG WHICH IS BASED ON THE BOOK AND EVOLUTIONARY MEDICINE IN GENERAL. COMMENTS AND RESPONSES STRONGLY INVITED!

Tuesday, 31 March 2015

The Skin You're In

http://www.pnas.org/content/early/2015/03/26/1424409112.full.pdf

We are used to explanations of the complexity of the human gut, with trillions of microbes representing thousands of species, comprising a gut microbiota invaluable to our health and the proper development of our immune systems. But there are two other complex surfaces in the human body that are also incredibly important to the commensal microbes that live on and in us. One is the lining of the lungs and the bronchial passages and the other is the skin. Skin is much more three-dimensional than we sometimes realize and is a very complex ecological area with numerous anatomical niches or a wide variety of microorganisms that are impacted by the detergents we clean our bodies with, skin conditions, and physical scarification. This paper explains the technology now available to describe the ecological complexity of skin in sufficient detail to really extend the hygiene hypothesis to this huge organ. Here is the abstract and the full paper is open access through the link above.


Molecular cartography of the human skin surface in 3D

The human skin is an organ with a surface area of 1.5–2 m2 that provides our interface with the environment. The molecular composition of this organ is derived from host cells, microbiota, and external molecules. The chemical makeup of the skin surface is largely undefined. Here we advance the technologies needed to explore the topographical distribution of skin molecules, using 3D mapping of mass spectrometry data and microbial 16S rRNA amplicon sequences. Our 3D maps reveal that the molecular composition of skin has diverse distributions and that the composition is defined not only by skin cells and microbes but also by our daily routines, including the application of hygiene products. The technological development of these maps lays a foundation for studying the spatial relationships of human skin with hygiene, the microbiota, and environment, with potential for developing predictive models of skin phenotypes tailored to individual health.

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