Its about gene therapy

1. GENE THERAPY
BY- SUBHASHREE DAS
M PHARM,1ST SEM

2. Contents:
 Introduction
 Types of Gene therapy
 Vectors used in gene therapy
 Methods of Gene delivery
 Advantages
 Disadvantages
 Recent developments
 References

3. INTRODUCTION
Gene therapy is the introduction of genes into the existing cells
to prevent or cure a wide range of diseases.
It is a technique for correcting defective genes responsible for
disease development.
The first approved gene therapy experiment occurred on
September 14,1990 in US.When Ashanti DeSilva was treated for
ADA-SCID.

4. Types of Gene therapy:
 It is of 2 types:
 1-Somatic cell gene therapy
 2-Germ line gene therapy
 1-SOMATIC CELL GENE THERAPY
 Therapeutic genes transferred into the Somatic cell
 Eg: Introduction of genes into bone marrow cells, blood
cells,
skin cells etc.
 Will not be inherited later generations
 At present all researches directed to correct genetic
defects
somatic cells.

5. 2-GERMLINE GENE THERAPY
 Therapeutic genes transferred into the germ cells.
 Eg: Genes introduced into eggs and sperms
 It is heritable and passed on to later generations.
 For safety, ethical and technical reasons,it is not
being
 attempted at present.

6. Techniques Of Gene therapy
2 types: 1- Ex vivo
2- In vivo
 1- EX VIVO GENE THERAP
1. Isolate cells with genetic defects from a patient.
2. Grow the cells in culture
3. Introduce the therapeutic genes
4. Select genetically corrected cells and grow
5. Transplant the modified cells to the patient.

7. 2-IN VIVO GENE THERAPY
1. Direct delivery of therapeutic genes into target cells of
patients body.
2. Carried out by viral or nonviral vector systems.
3. It can be the only possible option in patients,where
individual cell can not be cultured in vitro in sufficient
numbers eg : (brain cells).
4. Invivo gene transfer is necessary when cultured cells cannot
be re-implanted in patients effectively.

8. Examples of EX VIVO GENE Therapy:
 1st gene therapy to correct deficiency of enzyme, Adenosine
deaminase(ADA).
 Performed on a 4 years old girl Ashanti DeSilva.
 She was suffering from SCID- Severe combined
Immunodeficiency.
 Caused due to defect in gene coding for ADA.
 Deoxy adenosine accumulate and destroys T lymphocytes.

9. APPROACHES IN GENE THERAPY:

10. Vectors used for Gene therapy:
 2 types of Vectors used for Gene therapy.
 1-Viral vectors
 2- Non viral vectors
 1- VIRAL VECTORS
 Adeno virus vector system
 It is adeno virus with a DNA genome
 These are good vectors
 Targets- non dividing human cells.
 Eg-Common cold adenovirus.

11. Adeno virus vector system:

12. Non viral vectors:
 1-Pure DNA Construct:
 Direct introduction of pure DNA construct into the target tissue.
 Efficiency of DNA uptake by cells and expression is rather low.
 Consequently larger quantities of DNA have to be injected periodically.
 2-Lipoplexes:
 These are Lipid DNA complexes.
 DNA construct surrounded by artificial lipid layer.
 Most of it gets degraded by lysosomes.

13. Methods for Gene delivery:
 1- Physical method:
 Gene gun:
 Employes a High pressure delivery system to shoot
tissues with gold or tungsten particles that are
coated with DNA.
 2-Microinjection:
 Process of using a glass micropipette to insert
microscopic substance into single living cell
 Normally performed under a specialized optical
microscope setup called a micromanipulator.
GENE GUN

14. Chemical method:
 1.Using detergent mixtures:
 Certain charged chemical compounds like calcium
phosphate are mixed with functional cDNA of
desired function.
 Mixture introduced into the recipient cell and allow
cDNA to pass through the cell.
 2.Lipofection:
 It is used to inject genetic materials into a cell by
means of liposomes.
 Liposomes are artificial phospholipid vesicles used
to deliver DNA into cells.

15. Advantages:
 Gene therapy has the potential to eliminate and prevent
heredity diseases such as cystic fibrosis, ADA-SCID etc.
 It is a possible cure for heart diseases,AIDS and Cancer.
 It can be used to eradicate diseases from the future
generations.
 It is less expensive,sustained,and regulate gene expression.
 Therapy may only need to be delivered once.
 One gene can give rise to large no of protein molecules.

16. Disadvantages:
 Long lasting therapy is not achieved by gene therapy.
 They can cause immune response in patients.
 They can carry a limited amount of generic
material.Therefore,some genes may be too big to fit into
some viruses.
 Viruses used for vectors may cause toxicity, immune
response and inflammatory reaction in the host.
 Disorders caused by defects in multiple genes cannot be
treated effectively using gene therapy.

17. Recent developments:
 Stanford’s researchers are poised to use stem cells and gene
therapy to eradicate wide swath of diseases and for common
diagnosis like diabetes and Cancer to rare diseases of brain ,
blood,skin etc(.2017)
 In a new gene therapy method developed by University of
Florida in Jan2012, researchers found treatment for a
common form of blindness (X linked) that strikes both
youngsters and adults.
 A gene therapy called NLX-P101 dramatically reduces
movement impairment in Parkinson’s patients.

18. References:
 Essentials of Medical pharmacology, by KD
TRIPATHI.(6th edition pg-846-860)
 Essentials of Pharmacology by V N Sharma 3rd
edition ( pg-596-611)
 Wikipedia
 Harrison’s Text book of medicine-18th edition.
 Centre for Genetic Education. www.genetics.edu.au
 Google images.

19. Thank you…