‘Century of biology’ takes time to bear fruit

A microscopic view of muscle cells derived from human embryonic stem cells

Ten years ago, we stood on the brink of what many pundits predicted would be “the century of biology”, following the domination of the 20th century by physics and the 19th century by chemistry.

In June 2000, Bill Clinton and Tony Blair, the US president and UK prime minister of the day, held a White House press conference to celebrate the completion of a first draft of the human genetic code – identifying the 3bn chemical “letters” of our genome. Meanwhile, bioscientists were racing to exploit one of the great discoveries of the late 1990s: how to extract all-purpose stem cells from human embryos.

It is clear now that 21st-century bioscience has not delivered clinical and other results as quickly as some optimists – or hype-merchants – had expected. Medicine and healthcare have changed little over the decade, while the physics-based information technology industries have transformed people’s lives.

Today’s bio-optimists say the benefits from genomics, in the form of personalised medicine, may have been delayed but will appear soon, as the cost of DNA sequencing falls rapidly and its speed increases.

One sign of progress is the emergence in the past three years or so of GWAS (genome-wide association studies). This involves scanning the genomes of tens of thousands of people suffering from a particular disease and comparing them with the DNA of a healthy control population. The differences reveal clues to the genetic causes of the disease.

Researchers using GWAS have discovered hundreds of genes that contribute – alongside environmental factors – to multi-causal disorders such as diabetes, cancer and heart disease. These have given scientists a better understanding of disease mechanisms and should lead to diagnostic tests and treatments soon.

In addition, the cost of an individual DNA reading is falling so fast that the long-sought “$1,000 genome” is likely to be available commercially within the next couple of years. Knowledge of “pharmacogenomics”, the relationship between genetic variation and drug treatment, is also advancing quickly.

A big information gap must be filled before personalised medicine really arrives. This will require not only an affordable DNA sequence for each patient but also a reliable way to translate the findings into predictable medical consequences that can then be prevented or treated.

After genes, stem cells have provided a second theme of biomedical research in the past 10 years. These immature cells provide the gateway to regenerative medicine: the dream of replacing ageing, diseased or injured cells or body parts with new ones.

For most of the decade the emphasis has been on human embryonic stem cells, discovered by James Thomson at the University of Wisconsin in 1998. These are the most versatile stem cells, with the potential to become any type of specialist cell in the body, from bone to brain.

Embryonic stem cells have also provoked political controversy because their production involves the destruction of a pinhead-sized early human embryo – anathema to those who believe human life begins at conception, even if the aim is to prevent disease or to save a life. Many countries have banned human embryo research or placed stringent limitations on it.

Even so, scientists have made much progress in overcoming the obstacles to using embryonic stem cells, such as growing them in lab cultures and directing them to become the desired specialist cells. The first clinical trials of embryonic stem cells – to treat spinal injury or retinal disease – are expected in 2010.

The emphasis has to some extent switched away from embryonic stem cells in the past two years, partly because additional potential has been found in the less versatile but more easily handled stem cells taken from adult tissues.

But the main excitement has been the discovery of a type of cell, called the induced pluripotent stem cell or iPSC, which is made by treating adult cells with a biochemical cocktail that turns them directly into an embryonic state without having to make an actual embryo in the process.

Much work needs to be done in the next few years to establish the stability and safety of iPSCs before they can be considered for clinical trials. But they could eventually offer the benefits of embryonic stem cells without the practical and ethical objections.

By 2020, we will have a better idea of whether the century of biology is really on its way.