Melanin Deficiency

The following is part of an extract from the United States Government patent 5703051 Therapeutic uses of melanin or as we like to describe it “Melanin Therapy.”

One aspect of the present invention relates to the treatment of a mammal having a disease of a tissue which exhibits a melanin deficiency by the administration to the mammal of an effective amount of an active substance which causes an increased concentration of melanin in the effected [sic] tissue.

Melanin Deficiency: This term is intended to refer to a condition in diseased tissue in which melanin is absent, present in a lower amount when compared to normal tissue, or functionally non-active. The deficiency may be caused by a decrease in the synthesis of melanin and/or an increase in the catabolism or excretion of melanin. The melanin may be functionally non-active as the result of a substance binding to it which destroys the melanin’s activity.

It has now been found that the administration of melanin to a mammal having a disease of tissue which exhibits a melanin deficiency, such as the neurodegenerative diseases discussed above, is capable of ameliorating the primary neurological symptoms of the neurodegenerative disease which is treated.

It has now been found that the administration of tyrosinase to a mammal having a disease of a tissue which exhibits a melanin deficiency, such as the neurodegenerative diseases discussed above, is capable of ameliorating the primary neurological symptoms of the neurodegenerative disease which is treated.

A further method of treating the melanin deficiency diseases is to increase the concentration of naturally occurring melanin at the target cells in the central nervous system by the administration of melanin-concentrating hormone (MCH). Commonly, a combination of MCH and tyrosinase or tyrosinase gene is administered as an effective combination for the treatment of melanin deficiency diseases. The tyrosinase or tyrosinase gene causes an increased melanin production, and the MCH induces the aggregation of melanin in the target cells and tissues.

As in the case of treating melanin deficiency diseases, the amount of tyrosinase administered must be sufficient to catalyze the melanin producing reactions such that sufficient melanin is produced to alleviate the disease symptoms.

As is also the case with treatment of melanin deficiency diseases, another method by which the in vivo production of melanin may be enhanced us by the administration of the tyrosinase gene to the effected [sic] patient.

It has also been found that the administration of tyrosinase, tyrosinase gene, MCH or combinations thereof aid in the recovery of neurons. The tyrosinase increases the production of melanin in vivo, and the melanin accelerates the time frame for neuron recovery. The administration of tyrosinase gene and/or MCH aids in neuron recovery by promoting the same reactions described above for treatment and prophylaxis of melanin deficiency diseases

EXAMPLE 13 Preparation of Cloned Human Tyrosinase

Cloned human tyrosinase is prepared using the method of Kwon, B. S. as described in the published PCT application WO 88/02372.

The tyrosinase is produced in E. coli strain MM 294. The λmel 34 cDNA (as described by Kwon, B. S. in the same PCT application) is fused to a Tac expression vector (U.S. Pharmacia Inc.) which has Trp and lac promotor together. The construct is expressed in the E. coli strain MM 294 and subsequently purified by affinity column chromatography.

This tyrosinase is then used to treat diseases caused by a melanin deficiency.

EXAMPLE 14 Introduction of Human Tyrosinase Gene Into a Defective HSV-1 Vector

A defective herpes simplex virus 1 (HSV-1) vector, pHSVlac, has been developed by Geller, A. I., et al., Science 241, 1667 (1988). This vector is useful for transporting genes through the blood brain barrier.

The vector, pHSVlac, contains the Escherichia coli lacZ gene which is under the control of the HSV-1 immediate early 4/5 promoter. Using conventional publicly available endonucleases, pHSVlac is digested at its EcoRI sites to remove the E. coli lacZ gene. The λ mel 34 human tyrosinase gene (described by Kwon, B. S. in PCT application WO 88/02372) is then inserted to pHSVlac in place of the E. coli lacZ gene, and the vector is religated using conventional techniques.

This chimeric pHSVlac vector may then be used to introduce the tyrosinase gene into patients suffering from diseases caused by a melanin deficiency.