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1. Gene therapies
Presented to: Dr. Javed Ali
SPER, JAMIA HAMDARD
Presented by: Dipak Kumar Gupta
M.Pharm 1st yr.(II sem)
Pharmaceutics

2. What is gene therapy
• Gene therapy is the introduction of genes into existing cells to prevent or cure a
wide range of disease
• An experimental technique for correcting defective genes that are responsible for
disease development.
• The most common form of gene therapy involves inserting a normal gene to
replace an abnormal gene.
• Other approaches used:
 Replacing a mutated gene that causes disease with a healthy copy of the gene .
 Inactivating or “knocking out” a mutated gene that is functioning improperly.
 Introducing a new gene into the body to help fight a disease.

4. How it works
• A vector delivers the therapeutic gene into a patients target cell
• The target cells become infected with the viral vector
• The vectors genetic material is inserted into the target cell
• Functional proteins are created from the therapeutic gene causing the cell
to return to a normal state.

5. Types of gene therapy
• Somatic gene therapy
• Germ line gene therapy

6. Types of gene therapies

7. Somatic gene therapy
• Affects only the targeted cells in the patient, and is not pass to future
generations.
• Short –lived because the cells of most tissues ultimately die and are replaced
by new cells
• Transporting the gene to the target cells or tissue is also problematic.
• Appropriate and acceptable for many disorders including cystic fibrosis,
muscular dystrophy, cancer,and certain infectious diseases.

8. Germ line gene therapy
• Result in permanent changes.
• Potential for offering a permanent therapeutic effect for all who inherit
the target gene.
• Possibility of eliminating some diseases from a particular family.
• Also raises controversy:
• Some people view this type of therapy as unnatural, and like it to
“playing god”.
• Others have concerns about the technical aspects.

9. Approaches in gene therapy

10. Types of somatic cell gene therapy

11. Ex-vivo gene therapy
• Transplant the modified cells to the patient.
• Select genetically corrected cells and grow.
• Introduce the therapeutic genes .
• Grow the cells in culture Isolate cells with genetic defect from a patient

12. Ex-vivo gene therapy(process)

14. Example of ex-vivo gene therapy
• 1st gene therapy – to correct deficiency of enzyme, Adenosine deaminase
(ADA).
• Performed on a 4yr old girl Ashanthi DeSilva.
• Was suffering from SCID- Severe Combined Immunodeficiency.
• Caused due to defect in gene coding for ADA
• Deoxyadenosine accumulate and destroys T lymphocytes.
• Disrupts immunity , suffer from infectious diseases and die at young age.

15. In-vivo gene therapy
• Direct delivery of therapeutic gene into target cell into patients body.
• Carried out by viral or non-viral vector systems
• It can be the only possible option in patients where individual cells cannot be
cultured in vitro in sufficient numbers (e.g brain cells)
• In vivo brain transfer is necessary when cultured cells cannot be re-implanted in
patients effectively.

16. Examples of in-vivo gene therapy
• In patients with cystic fibrosis, a protein called cystic fibrosis trans-
membrane regulator (CFTR) is absent due to a gene defect.
• In the absence of CFTR chloride ions concentrate within the cells and it
draws water from surrounding.
• This leads to the accumulation of sticky mucous in respiratory tract and
lungs.
• Treated by in vivo replacement of defective gene by adenovirus vector

17. In-vivo gene therapy

18. METHODS OF GENE DELIVERY
PHYSICAL METHODS
 Gene Gun
• Employs a high-pressure delivery system to shoot tissue with gold or
tungsten particles that are coated with DNA
 Microinjection
• Process of using a glass micropipette to insert microscopic substances
into a single living cell.
• Normally performed under a specialized optical microscope setup called a
micromanipulator.

19. CHEMICAL METHODS
 USING DETERGENT MIXTURES
• Certain charged chemical compounds like Calcium phosphates are mixed
with functional cDNA of desired function.
• The mixture is introduced near the vicinity of recipient cells.
• The chemicals disturbs the cell membrane, widens the pore size and
allows cDNA to pass through the cell.
 LIPOFECTION
• It is a technique used to inject genetic materials into a cell by means of
liposomes.
• Liposomes are artificial phospholipid vesicles used to deliver a variety of
molecules including DNA into the cells.

20. GENE THERAPY
GENE AUGMENTATION THERAPY
• Most common form of gene therapy
• Foreign gene replaces missing or defective gene.
• Eg. Replacement of defective p53 gene by a normal one in liver cancer.
 GENE INHIBITION THERAPY
• Done to block the overproduction of some proteins.
• 2 types – Antigene and antisense therapy.
• Antigene – blocks transcription using antigene oligonucleotide
• Antisense – blocks transalation using antisense oligonucleotide

21. Contnd.....
• Long lasting therapy is not achieved by gene therapy; Due to rapid dividing
of cells benefits of gene therapy is short lived.
• Immune response to the transferred gene stimulates a potential risk to
gene therapy.
• Viruses used as vectors for gene transfer may cause toxicity, immune
responses, and inflammatory reactions in the host.
• Disorders caused by defects in multiple genes cannot be treated
effectively using gene therapy.
• Gene therapy has the potential to eliminate and prevent hereditary
diseases such as cystic fibrosis, ADA- SCID etc.
• It is a possible cure for heart disease, AIDS and cancer.
• It gives someone born with a genetic disease a chance to life.
• It can be used to eradicate diseases from the future generations.

22. ADVANTAGES
• Gene therapy has the potential to eliminate and prevent hereditary
diseases such as cystic fibrosis, ADA- SCID etc.
• It is a possible cure for heart disease, AIDS and cancer.
• It gives someone born with a genetic disease a chance to life.
• It can be used to eradicate diseases from the future generations.

23. DISADVATAGES
• Long lasting therapy is not achieved by gene therapy; Due to rapid dividing
of cells benefits of gene therapy is short lived.
• Immune response to the transferred gene stimulates a potential risk to
gene therapy.
• Disorders caused by defects in multiple genes cannot be treated
effectively using gene therapy.
• Viruses used as vectors for gene transfer may cause toxicity, immune
responses, and inflammatory reactions in the host.

24. references
• Dubey R.C, A textbook of biotechnology, 1st edition (2004), S Chand and
company, New Delhi
• Gupta P.K, Elements of Biotechnology, 1st edition(2001), Rastogi
Publications, Meerut.
• http://www.medindia.net/articles/genetherapy treatment.htm