Biotechnology in medicines
Modern biotechnology has the potential to make the 21st century an era of the most profound and wide-ranging progress in the history of medicine. Compared to the advent of antibiotics, which created a revolution in the treatment of infections caused by bacteria, advances in genetic science have the potential to create a revolution in the diagnosis and treatment of many diseases and inherited disorders. Today we cover here brief information about biotechnology in medicines.
The revolution began with a fundamental discovery which opened the door to a new level of scientific understanding in the field of genetics. The discovery of the chemical basis of life – the DNA molecule – happened in the early 1950s. More than 50 years later, the mapping of the human genome has provided a framework to identify each human gene and the specific roles they perform.
Scientists are also mapping the genetic codes of bacteria, viruses and other disease-causing organisms, and discovering how their genes interact with our own to cause disease. Scientists can also read the DNA of individual humans to compare their genetic characteristics with our rapidly advancing knowledge of the roles of each human gene. In the future, it may be possible to develop individual “genetic profiles”, to allow comparison with a much wider range of genetic conditions and predispositions than is currently known – and these could be contained on just a single microchip.
Other fact sheets in this series outline how biotechnology is working to enhance the practise of medicine in specific areas . Here we provide an overview and some examples of this new era of biotechnology in medicine.
Traditional diagnostic tools rely on physical or behavioural symptoms, chemical analysis of affected tissues and bodily fluids, scans, and other techniques. Biotechnology’s new tools can contribute to a diagnosis by looking at a patient’s genes to assess possible roles in illness. Where a disease is known to be caused by one or a few genes (such as cystic fibrosis), or an extra chromosome (such as Down syndrome), genetic testing alone can provide a definitive diagnosis. However, genetic testing should always be done in conjunction with clinical examination and diagnosis. Genetic analysis of bodily fluids can also be used to identify DNA from viruses and other infectious agents, providing an additional method of diagnosing infection.
Preventative health care
Genetic testing is adding a powerful new dimension to enabling individuals to manage their health. In May 2004 scientists reported that they had produced complete maps of human chromosomes 9 and 10 and identified the 1,965 genes they carry. As the map is completed and further explored, a multitude of opportunities will emerge for testing a wider range of genetic markers. Over the coming decades, it may be possible to create complete genetic profiles of individuals.
Heightened susceptibility to breast cancer has already been linked to several genes. This knowledge could help women who carry those genes to exercise increased vigilance by having scans more frequently than would be recommended for the general population. In coming years the specific roles of these and other genes will be better understood, as will the roles of genes in other diseases, and the interactions between genes and the environment.
People with a genetic susceptibility to diabetes, osteoporosis, heart disease or other disorders could be guided to shape their diet and lifestyle to prevent their onset, and to reduce the risk of contracting many kinds of cancers which are caused by a combination of genetic and lifestyle factors.
Many people value the advantage of using their personal genetic knowledge to enhance their health, but this kind of knowledge is not necessarily welcomed by all. The issues it can raise can be difficult for individuals to deal with when they discover they you have a predisposition to an illness, while people without such a predisposition may become dangerously complacent about their health. Patients can choose not to know their genetic status for particular diseases and conditions, or can withhold information from others (see Genetic Privacy). Counselling is required at all stages of the decision-making process.
Knowledge of an individual’s genetic inheritance could help to eliminate a great deal of human suffering. If a healthy person knows they carry the genes for a disease that emerges in middle-age, they can plan many aspects of their lives accordingly and be fully informed when making decisions about parenting. Parents who know their foetus has a genetic disorder, and who receive appropriate genetic counselling, can decide to continue or terminate the pregnancy with full knowledge of possible physical and emotional consequences.
In some cases, parents of a child with an inherited disorder can pursue the option of curing the illness by having another child with the same tissue type, but lacking the gene causing the disorder. Ensuring that the second child has the same tissue type as its brother or sister involves using pre-implantation genetic diagnosis. Embryos created through in vitro fertilisation are screened, and those with the same tissue type as the ill sibling are implanted in the mother. When the baby is born, stem cells can be taken from its umbilical cord blood and transplanted to the sick child in the hope of treating the condition. In early 2004 a Melbourne family were the first Australians to benefit from this kind of treatment which applies techniques developed for in vitro fertilisation (IVF).
Stem cells from the umbilical cord of the couple’s second child were infused into the bone marrow of their first child who had inherited an immune deficiency disorder. These cells were not rejected because the tissue compatibility of the children had been confirmed by analysis of the second child’s DNA before the embryo was implanted in the mother’s womb. The analysis also confirmed that the second child had not inherited the genes which caused the firstborn’s illness. The infused stem cells survived and multiplied, correcting the firstborn’s immune deficiency which would otherwise have caused lifelong suffering and possible premature death.
All these treatments raise complex ethical questions and access to IVF for the purpose of creating a second child to treat the first must be approved by the relevant ethics committees.
Since the 1980s the production of medical insulin has undergone a radical change. Previously sourced from the pancreatic tissue of pigs and cattle, almost all insulin is now produced by industrial cultures of E. coli bacteria which have the human gene for insulin production added into their DNA, although genetically modified yeast are now also being used to produce insulin. Biotechnology has aided the development and production of antibiotics and specific compounds, such as interferon alpha to treat hepatitis C and cancer, and trials of crop plants modified to produce vaccines for a variety of human and animal diseases are also underway.
By studying the genetics of viruses, fungi and bacteria that infect humans, we can understand how they cause disease and develop drugs that target them more specifically. Many approaches to treating HIV/AIDS and other viruses target their genetic makeup. Others, such as the Relenza treatment for influenza developed by Australian company Biota, rely on knowledge of the molecular structure of proteins on the surface of the influenza virus to stop an infection spreading.
Organ and tissue replacement
Matching the genetic types of organ donors and potential recipients enables the risk of organ rejection to be minimised, while ongoing advances in molecular biology are providing improved techniques to ensure the long-term health of transplant recipients. In the future, cloning for medical purposes offers the prospect of eliminating the problem of rejection because new organs or tissue – such as skin grafts for burns victims – could be grown from a patient’s own cells. This type of procedure is currently prohibited in Australia.