In search of a versatile virtual person

Today, the burgeoning volume of biological information has grown so large that it threatens to overwhelm rather than enlighten scientists. With the power of the computer, however, researchers are using the available raw data to refine the crude qualitative models of yester-year into finely tuned simulations that can represent − and even predict − the behavior of complex biological systems.

The virtual heart developed by Denis Noble at the University of Oxford shows vividly how useful biological modeling can be. Noble’s heart is a carefully assembled mass of virtual cells, each processing virtual sugar and oxygen and behaving just like the real thing. Noble can watch his virtual heart beating on a computer screen. He can make it develop diseases, then treat it with virtual drugs. Drugs companies have used his heart to test for adverse reactions.

Noble is a co-founder of Physiome Sciences, a company that specializes in modeling human organs and cells for the pharmaceuticals industry. Physiome has crude but functioning models of dozens of types of human cells, and is working on building them into complete immune, endocrine and bone systems. It’s part of a whole new industry that is springing up, offering pharmaceuticals companies virtual versions of everything from single receptors to multiorgan systems for testing potential drugs. Entelos, for example, a modeling company based in the heart of Silicon Valley at Menlo Park, California, specializes in simulating disease states. Its computer model of asthma includes elements of every relevant structure and process, from airways to immune cell reactions. Companies like these, along with academic researchers, try to stitch their efforts together – and run the resulting model – a rudimentary Virtual Human.

The Virtual Human may give us new and unexpected insights into the way our bodies work. When biologists program in some new observations about the pancreas, say, it might influence parts of the Virtual Human that no one had ever guessed would be affected, such as the lungs or the heart. The answers to mysterious medical problems could emerge every time the model is examined or altered, Easterly believes.

The Virtual Human could also be customized to isolate the effects that drugs have on different individuals, allowing researchers to investigate the influence of sex, age, racial background or any other factor, without the need for elaborate time-consuming and expensive clinical trials. With that technology in place, Easterly says it should eventually be possible to create a virtual version of every one of us, tailored to our individual genome medical history and other specifics.

But even the most ambitious modelers are steering clear of one important organ: the brain. “There is every possibility of modeling a human neuron, and perhaps a cluster of neurons,” explains Levin, “but modeling the human brain is outside the realm of our reality.” As long as they model the brain’s basic outputs – the autonomic nervous system and endocrine signals, for example – the researchers believe the body will still function normally.

Perhaps it’s for the best that the Virtual Human will be devoid of brain power. As it vomits up new antibiotics, takes a hail of bullets in the chest, and develops a particularly nasty skin cancer, it can do without the added burden of realizing what a rotten day it’s having.