Role of Genetic engineering in Medicine

In 1982 the United States Food and Drug Administration (FDA) approved for the first time the medical use of a recombinant DNA protein, the hormone insulin, which had been cloned in large quantities by inserting the human insulin gene in Escherichia coli bacteria.

• tissue plasminogen activator (tPA), an enzyme used to dissolve blood clots in people who have suffered heart attacks, and erythropoetin, a hormone used to stimulate the production of red blood cells in people with severe anemia.
• To produce medically useful human proteins in animal milk.
• In the production of vaccines against disease. A vaccine contains a form of an infectious organism that does not cause severe disease but does cause the body’s immune system to form protective antibodies against the organism. Vaccination with genetically altered vaccinia is now being used against hepatitis, influenza, and herpes simplex viruses. Genetically engineered vaccinia is considered safer than using the disease-causing virus itself and is equally as effective.
• Gene therapy, in which a healthy gene can be directly inserted into a person with a malfunctioning gene, is perhaps the most revolutionary and promising of recombinant DNA technologies,

Stem cells

A landmark decision by the Bush Administration — in the face of stiff opposition from the Christian fundamentalist groups, Roman Catholic Church, prolific activists, anti-abortion groups and extreme right wing politicians — to continue federal funding for research on “ostern cell lines” could go a long way towards boosting the prospects of stem cell research which holds the promise revolutionizing the treatment for a variety of human diseases and disorders, including Alzheimer’s, diabetes, Parkinson muscular dystrophy, epilepsy and various forms of mental ailments.

The debate erupted again with the decision of a lower court to ban the federal funding for stem cell research, however after long and heated debate the obama administration allowed the funding pending the final resolution of the matter.

What are stem cells?

STEM cells are undifferentiated cells that can evolve into blood, liver, muscle and other specialized cells. Human Embryonic Stem Cells (hESCS) are unique because they make up the earliest form of human life and have the power to be developed into nearly any other type of cell or tissue in the body. Unlike hESCs, adult stem cells, which are derived from adult tissues, are believed to produce only one type of specialized cell or tissue. One example of an adult stem cell is the blood stem cells that are found in the bone marrow. These stem cells can only, at least so far, be developed only into blood cells. These blood stem cells perform the critical role of continually replenishing our supply of blood cells throughout life. Biological researchers view embryonic stem cell as body’s early building blocks. Their wondrous ability to transform themselves into virtually any cell type enables the embryo to grow from a round ball of few cells into a fully formed human being. Essentially, stem cells are undifferentiated cells that can evolve into blood, liver, muscle and other cells and could one day be used to repair damaged organs.

Two type of stem cells

• Embryonic stem cells – derived from the inner mass of mammalian embryo at a very early stage of development, when it is just a hollow ball of dividing cells called blastocyst.
• The embryonic stem cells at early stage are totipotent (give rise to any cell type of the adult organism).
• The embryos from which stem cells are harvested are generally developed through in vitro fertilization (fertilized outside human body) so that ethical concerns are met.
• Adult Stem Cells – Present in adult human body.
•  They form part of some tissues like the epidermis of the skin, the lining of the small intestine and the bone marrow which undergoes continuous cellular change.

Classification of stem cells based on their dividing capacity:

1.   Pluripotent Stem Cells

• can divide into various different cell types except for totipotent stem cells and cells of placenta.
• develope about four days after the fertilization.

2.   Totipotent Stem Cells

• capacity to differentiate into any cell type including placenta (which nourishes the embryo ).
• develop in first few divisions of the fertilization.

3.   Multipotent Stem Cells

• descendents of pluripotent stem cells and antecedents of specialized cells in particular tissues.
• Example : Hematopoietic stem cells ( found in the bone marrow ; give rise to all type of cells found in blood- including red blood cells, white blood cells and the platelets), Neural stem cells- which can differentiate into nerve cells.

Sources of Stem Cells

Embryonic Stem (ES) cells

• Derived from human embryos that are few days old
• Have the potential to become almost any type of cell.
• Difficult to manipulate
• Ethically contentious as the embryo is destroyed in the process

Foetal Stem Cells

• Derived from aborted human foetuses
• Have the potential to become many of the cell types
• Ethically contentious and limited availability

Cord blood and placental stem cells

• Derived from umbilical cord blood and placentas
• Already used in a variety of therapies
• Easily extractable
• Can currently only from a limited number of cell types
• Available in low concentrations

Adult stem cells

• Found in all humans
• Already in use for some therapies
• Sometimes difficult to access
• Can currently form a limited number of cell types

Use of Stem Cells[1]

Stem cells, now a days being popularly used to treat untreatable diseases (heart disease, spinal cord injuries, Parkinson's, Alzheimer's disease, etc.), have attracted the attention of Indian Council for Medical Research (ICMR) and will now be used only under approved and monitored clinical trials. ICMR has given fresh guidelines countrywide over the use of them which will consequently prevent exploitation of patients by clinics which offer unproven stem cell treatment prematurely. As India becomes a global centre for clinical trials, the question of ethical oversight becomes increasingly difficult to ignore.

In a collaborative decision of ICMR and the Department of Biotechnology considering the recommendation of a joint drafting committee of the two, the word “therapy” which was till now used along with “stem cell” has been removed as the practitioners are yet to verify the therapeutic efficacy of the use of stem cells in humans. Going with a more appropriate stand the word research has been tagged along with it as the use of stem cells is still under trial mode in case of many ailments. And, these guidelines, seven years after the last time they were issued, will cover only the research area of stem cells and not therapy. Usage of stem cells for reconstitution (in regenerative medicine) is still investigational for all approved indications except for haematopoietic stem cell i.e. those producing red and white blood cells and platelets and  used in treating haematological, immunological and metabolic disorders. These fall under standard medical care now-a-days. Further stating the guidelines have brought all the treatments except the ones mentioned above under the umbrella of clinical trials.

• Due to its reconstitution ability stem cell is widely being used for:
• drug development
• toxicity testing
• developmental biology
• disease modelling
• tissue engineering
• It is a potent tool for restoration of cell functionality in eventualities like cell degeneration or damage. However, there are social, scientific and ethical concerns which have raised barriers in its usage.

Issues on Human Embryonic Stem (HES)

Derivation of pluripotent embryonic stem (ES) cells from human blastocysts (structure formed in the early development of mammals) has been possible now but there are alarms raised at the same time as people essentially prefer potent donors leading to discriminating trends in practice, exploitation of individuals and proliferation of unethical medical practices. This may further lead to commoditisation of human tissues and cells.

The Constitutional Debate:

In a debate raised in Africa, permission for research on embryos not older than 14 days can be granted under the legislation but it restricts the scientific temperament and initiatives. The Bill of Rights is not applicable to the unborn. It has been argued based on constitutional grounds (the right to human dignity, and the right to freedom of scientific research) that the limitations on embryo research are overly inhibitive of the autonomy of scientists, and hence unconstitutional.

Global Position of Stem Cell Research

The field is not regulated by uniform international laws but nations have enforced their respective legislations. Europe though has taken a lead in stem cell research has not issued regulatory guidelines for it for EU as a whole. While Germany, Austria, Italy, Finland, Greece, Ireland, Portugal and the Netherlands have banned the use of embryonic stem cells, Sweden and the United Kingdom (Human Fertilisation and Embryology Act 1990) have created the legal grounds to aid this area of research. Similar to Sweden, Belgium bans reproductive cloning but allows therapeutic cloning of embryos. France has enacted laws systematizing the in-vitro fertilization treatment in the country. Most Asian nations ban reproductive cloning but not therapeutic cloning for the sake of promoting research and knowledge enhancement on untreatable diseases. The USA has both federal and state laws in place regulating the subject. To note, Brazil legislated for excessive utilization of in-vitro fertilization techniques, supported by massive storage banks, permitting use of embryos frozen for as long as three years.

The increasing global perspective in stem cell research &therapy mandates design and implementation of a robust regulation and oversight along with steps to enhance public knowledge and awareness.

All ethical principles governing research must also be ensured in stem cell research, viz.:

• Voluntariness
• Informed consent
• Risk minimization
• Privacy
• Accountability and transparency
• Ownership of responsibility
• Competence and compliance, etc.

First human liver made from stem cells

Scientists in Japan said they had grown human liver tissue from stem cells in a first that holds promise for alleviating the critical shortage of donor organs. They first created induced pluripotent stem (iPS) cells which they mixed with other cell types and coaxed into "liver buds" -- the precursor clusters that develop into a liver. The buds, each about five millimeters (0.2 inches) big, were then transplanted onto a mouse brain, where they were observed transforming into a "functional human liver" complete with blood vessels. The technique has yet to be tested in humans, but serves as an important proof of concept.

In September 2014, Scientists in Kobe Japan, was implanted with retina produced with ips cells. Japanese woman in her 70s is the world's first recipient of cells derived from induced pluripotent stem cells

Vaccine Research and Production

The incidence of communicable diseases in India has been one of the highest in the world there by contributing significantly to the morbidity, mortality and disability, particularly in the children under the age of five years. In order to achieve self-sufficiency in some of the major EPI Vaccines, two-vaccine production cum R & D units viz. BIBCOL and IVCOL, under national technology mission on immunization in March 1989 for production of human viral vaccines were established.

BIBCOL, Bulandshahr is to manufacture 100 million doses of oral polio vaccine and other immunologicals, with technical know-how from the IPVE, Moscow (Russia). The IVCOL, Gurgaon, is to produce OPV indigenously, rabies using vero cell based micro-carrier technology and measalis vaccine.

DNA FINGERPRINTING

DNA fingerprinting or DNA typing, is a DNA-based identification system that relies on genetic differences among individuals or organisms. Like fingerprints, every human has unique DNA; unlike fingerprints which can be surgically altered, one can’t change the DNA.Fingerprint evidence can be too fuzzy to be read well, but DNA patterns are clear.

Procedure of DNA fingerprinting:

• Isolation of DNA: DNA must be recovered from the cells or tissues of the body. Only a small amount of tissue – like blood, saliva, semen, hair or skin.
• Cutting, sizing and sorting: Special enzymes called restriction enzymes are used to cut the DNA at specific places. The DNA pieces are sorted according to size by a sieving technique called electrophoresis. The DNA pieces are passed through a gel made from sea weed agarose.
• Transfer of DNA to nylon: The distribution of DNA pieces is transferred to a nylon sheet by placing the sheet on the gel and soaking them overnight.
• Probing: Adding radioactive or coloured probes to the nylon sheet produces a patterns called the DNA fingerprint. Each probe typically sticks in only one or two specific places on the nylon sheet.
• DNA fingerprint: The final DNA fingerprint is built by using several probes (5-10 or more) simultaneously. The segments marked with probes are exposed on X-ray fil, where they form a characteristic pattern of black bars – the DNA fingerprint.

Applications of DNA fingerprinting

• Forensic Uses: In criminal investigations, DNA from samples of hair, bodily fluids or skin at a crime scene is compared with those obtained from suspected perpetrators.  DNA typing is also used to identify the remains of unknown individuals, as in the identification of the soldiers, or to identify the bodies of people killed in political violence or accidents whose bodies are unrecognizable.
• Paternity: Paternity determination is possible with DNA typing because half of the father’s DNA is contained in the child’s genetic material.
• Anthropology: DNA fingerprinting has also been used extensively to identify human remains, solving long-standing mysteries. DNA has had an enormous impact on anthropology as well.
• Wildlife Management: The more the genetic makeup of natural populations is understood, the better conservation and management plans will be.

Proteom­ics

The next after Genomics is the fundamental research on ‘Proteom­ics’ and Study of centre is protein

It’s generally believed that patterns of protein production-‘the Proteome’-will correlate with disease states, which shall lead to new treatments.

Proteins are central to our understanding of cellular function and disease processes, and without a concerted effort in proteomics, the fruits of Genomics will go unrealized.