GENE THERAPY

the introduction of normal genes into cells in place of missing or defective ones in order to correct genetic disorders.

TYPES OF GENE THERAPIES

• The defective gene in the case of CF carries the code for a protein called the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). This protein regulates the movement of salt and water in and out of cells and the alteration of this protein is what causes the thick, sticky mucus typical of CF.

GENE THERAPY FOR CYSTIC FIBROSIS

CHOICE OF VECTORS:

• Viral vectors:• Vetrovirus• Adenovirus• Adeno-associated

virus• Herpes Simplex Virus

• Non-viral vectors:• Liposome• DNA–polymer conjugates• Naked DNA

The ideal vector system would have the following characteristics:

• an adequate carrying capacity; • to be undetectable by the immune system; • to be non-inflammatory; • to be safe to the patients with pre-existing lung

inflammation; • to have an efficiency sufficient to correct the cystic

fibrosis phenotype; • to have long duration of expression and/or the ability

to be safely re-administered.

1993 vector used:ADENOVIRUS

1995 vector used:LIPOSOME

1998 ADENO-ASSOCIATED VIRUS

MODE OF DELIVERY• The majority of experience in terms of vector

delivery to the lungs has involved the instillation of large volumes of vector-containing fluid into the lung via the nose.

Another mode of lung delivery for vector-containing fluid is by oral inhalation of aerosolized vectors.

• One way to avoid alveolar deposition is to generate an aerosol that is composed primarily of large droplets.

• Delivery of the vector by means of a spray device that is inserted into a bronchoscope may have another advantage over nebulization.

PROS CONS

• Fixes the problem

• Gene therapy is a fast growing field

• Part of the Hippocratic Oath states, "that I will lead my life and practice my art in uprightness and honor; that into whatsoever house I shall enter, it shall be for the good of the sick to the utmost of my power...that I will exercise my art solely for the cure of my patients".

• Changes the gene expression of the entire generation

• Researchers aren’t sure of the results of the therapy

• ethics are being involved in changing the human being’s make up.