Application of Biotechnology in Medicine

Biotechnology is a field that applies different techniques to biological organisms for better output. With the increase in human population, there is an increased need of necessity for a healthy continuance of life. The foremost demand is to improve the quality and quantity of food products from different resources. Other than this the area of pest control by the production of herbicides, the production of medicines, and life-saving hormones like insulin, has become effective cost-saving practices for the betterment of life.

• The term biotechnology had been coined by Hungarian engineer Karl Erky in 1919. 
• Biotechnology involves the manipulation of living organisms by molecular and cellular processes to improve our lives and health of the planet. 
• Modern biotechnologists have acquired the act of cutting a sequence of DNA of interest from a genome and inserting it into another genome for the multiplication of the same gene for different useful purposes.

Biotechnology finds its application across a multitude of fields and industries, such as pharmaceuticals, medicine, food, and agriculture. Its reach encompasses both research and engineering. One of the ways genetic engineering has contributed to the field is by aiding in the production of therapeutic proteins and biological organisms. Significant strides have been made in molecular biology and industrial biotechnology thanks to biotechnology.

Key Terms: Biotechnology, recombinant DNA technology, insulin, vaccine, gene therapy, disease.

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Applications of Biotechnology in Medicine

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Biotechnology has made significant contributions to the field of medicine. Some of the applications of biotechnology in medicine include:

Production of human insulin

Insulin is a hormone secreted from the pancreas for maintaining glucose levels in the body. A deficiency of this hormone, a condition called diabetes mellitus, leads to an increase in blood sugar levels. 

• Patients with low levels of insulin are injected with small doses of insulin. 
• These insulin were earlier extracted from the pancreas of slaughtered animals. 
• Nowadays, it is possible to synthesize human insulin through recombinant DNA technology. 

The easiest way of doing this is by taking out the human insulin genes from human leucocytes and prepare a recombinant DNA. The problem lies here, that mature insulin contains A and B chains while the pro-insulin contains an additional C-peptide which needs to be cleaved. This was a major challenge.

Eli Lilly, an American pharmaceutical company, 1983, prepared the two DNA sequences of the A-chain and the B-chain separately by reverse transcription their mRNA. These were then introduced in the genome of E. coli. The chains were produced separately, then extracted and combined by disulfide bonds to produce mature human insulin on a large scale. Since it is exactly similar to human insulin, it is often called humulin.

Production of hirudin

Hirudin is an anti-coagulant. It naturally occurs in the salivary gland of sanguinivorous (blood-sucking) leeches such as Hirudo medicinalis. The gene of hirudin was chemically synthesized and was introduced in rapeseed plants (Brassica napus). The accumulated protein was extracted from the seeds, purified and used as medicine. 

Production of vaccines

Recombinant DNA technology is being used recently for the development of various second-generation vaccines. These vaccines have a more uniform quality and create lesser side effects than first-generation vaccines. The vaccine for hepatitis B (HBSAG) is the first synthetic recombinant vaccine which is being used since 1987 against the hepatitis B virus with efficacy and without allergic reactions. 

• In 1990 DNA vaccines had been developed for genetic immunization, i.e. by the administration of a DNA molecule in the body, the immune response is stimulated against some diseases. 
• It consists of a DNA gene encoding an antigenic protein which remain incorporated in a plasmid and then introduced into the cells of the target animal for immunization. 
• Thus the plasmid vaccine containing DNA for antigenic protein, after entering into the nucleus of the target cells of the host produces RNA and the specific antigenic proteins and these in turn develop immunity (humoral) of the specific animal.

Gene therapy

Gene therapy is a technique that is used for correcting defective genes. It typically aims to replace a defective gene with a functional one. There are three ways for the correction of defective genes—

• Gene addition- Insertion of a functional gene at a non-specific location into the genome.
• Gene replacement- Replacement of an abnormal gene with a normal and functional gene by homologous recombination.
• Repair of an abnormal gene to regain its normal function by reverse mutation. 

Gene therapy may be of the following types— 

1. Germ-line gene therapy modifies the genome of a gamete or of a zygote that can be transmitted.
2. Somatic gene therapy introduces functional genes into the somatic cells of a diseased person.

Example- In 1990, the first case of gene therapy took place. 

• The patient was a four-year-old child diagnosed with severe combined immune deficiency (SCID). 
• People with SCID have damaged immune systems lacking all immune protection from viruses, bacteria, fungi and other pathogens. 
• This was due to the deficiency of an enzyme called Adenosine deaminase (ADA). 
• The patient received genetically modified white blood cells with functional genes for ADA.

Gene therapy may again be of classical and non-classical types. Classical gene therapy delivers functional genes to proper target cells for appropriate expression of the genes that have been introduced. Non-classical gene therapy is used to correct genetic defects for restoration of expression of the normal functional gene.

Molecular diagnosis

Conventional diagnostic methods like urine and serum analysis are not instrumental in the early detection of disease. Early diagnosis is now possible with the help of biotechnological methods. A few methods of molecular diagnosis of diseases are as follows:

1. Polymerase Chain Reaction or PCR is an important tool to amplify DNA. This technique identifies the genetic change that is responsible for causing disease. It also identifies the genetic material of the pathogen. This technique is employed to detect HIV in patients suspected of AIDS.
2. Enzyme-linked Immunosorbent Assay test or ELISA is a technique used to detect a very small amounts of antibodies or antigens with the help of certain enzymes. ELISA is a convenient method for early detection of AIDS, STDs, Hepatitis, etc. disorders

Read more: Nucleic acids

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Things to remember

1. Human insulin has to be produced on a large scale due to the increasing rates of diabetes mellitus around the world.
2. The C-peptide sequence is cut from pro-insulin to produce human insulin with A and B chains. Eli Lilly was the first to overcome this hurdle.
3. Genetically engineered insulin is mostly similar to that of human insulin and so it is called humulin.
4. Hirudin is an anticoagulant which is produced in large scale by introducing the gene into the Brassica napus plant and then extracted and used as medicine.
5. Gene therapy is a technique that corrects defective genes or introduces a functional one in the genome.
6. Biotechnological methods like PCR and ELISA are instrumental in the early detection of diseases like STDs, AIDS, cancer, etc.

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