Systems and methods for predicting response to minoxidil for the treatment of androgenetic alopecia
Methods, processes, systems, and apparatuses are disclosed for predicting minoxidil response in the treatment of androgenetic alopecia based on colorimetric assay for sulfotransferase activity. In particular, SULT1A1 activity may be used as an indicator of minoxidil response. A genetic test for alleles of the SULT1A1 gene may be performed to provide a more personalized therapy.
1. A method of developing a treatment for a human subject suffering from androgenetic alopecia, comprising:
obtaining a sample from the human subject, comprising one or more hairs that have been plucked from the human subject, said hairs comprising one or more hair follicles;
performing a colorimetric assay to measure a sulfotransferase enzyme activity in the sample, thereby generating an activity value indicative of the sulfotransferase activity level in the sample, wherein the assay comprises the step of placing the sample in a reaction mixture comprising an indicator dye and minoxidil, and wherein during the assay, the indicator dye undergoes a color change that correlates with the amount of sulfotransferase activity level in the sample, and wherein the activity value correlates with said color change;
performing a genetic test on the human subject to determine a cause of the sulfotransferase activity level represented by the activity value, the genetic test comprising genotyping the human subject to identify the presence of a predetermined allele of sulfotransferase;
comparing the activity value to one or more standardized activity values, each standardized activity value representing either high or low expected minoxidil response for hair re-growth or retention for a class of human subjects including the human subject, thereby producing an indication of either high or low expected minoxidil response for hair re-growth or retention for the human subject at a particular dosage and form of minoxidil; and
developing an androgenetic alopecia treatment for the human subject based on the high or low expected minoxidil response.
2. The method of claim 1 , wherein the indicator dye is p-nitrophenyl sulfate.
3. The method of claim 2 , wherein the assay further comprises the steps of:
placing the sample in a reaction mixture containing about 30 to about 70 mM potassium phosphate buffer with pH between about 6.5 and about 8.0, about 3 to about 7 mM magnesium chloride, about 15 to about 25 μM adenosine 3′,5′-diphosphate (PAP) or adenosine 3′-phosphate, 5′-phosphosulfate (PAPS), about 3 to about 7 mM p-nitrophenyl sulfate and about 0.07 to about 0.13 mM minoxidil;
mixing the reaction mixture which contains the sample, such that a reaction is initiated;
incubating the sample within the reaction mixture for a predetermined length of time sufficient to bring the reaction to substantial completion; and
stopping the reaction.
4. The method of claim 3 , wherein the assay further comprises adding a basic buffer of about 0.25 M Tris-HCl, pH approximately 8.7 to the reaction mixture to quench the assay.
5. The method of claim 1 , wherein generating an activity value is performed by measuring the optical density at approximately 405 nm with a spectrophotometer.
6. The method of claim 5 , wherein the one or more standardized values are a cut-off value at which, within a statistical sample of other human subjects, there is a sensitivity of at least about 75% for prediction of positive hair re-growth or retention response to treatment by minoxidil, and a selectivity of at least about 50%.
7. The method of claim 6 , wherein the sensitivity is at least about 90%, and the selectivity is at least about 65%.
8. The method of claim 1 , wherein the colorimetric assay uses 2-naphthol as a substrate, to improve the sensitivity or specificity of the assay.
9. The method of claim 1 , wherein the sample consists of one hair comprising one hair follicle that has been plucked from the human subject.
10. The method of claim 1 , wherein the reaction time for the assay is inversely correlated with the number of hair follicles in the reaction.
11. The method of claim 1 , wherein the human subject with high sulfotransferase activity is prescribed a low dose of minoxidil and/or a decrease in the frequency of minoxidil application.
12. The method of claim 1 , wherein the human subject with low sulfotransferase activity is prescribed a high dose of minoxidil and/or an increase in the frequency of minoxidil application.
13. The method of claim 1 , wherein the sulfotransferase is SULT1A1.
14. The method of claim 13 , wherein:
the human subject exhibits low SULT1A1 activity; and
the genetic testing comprises performing a test of a biological sample from the human subject for the presence of a predetermined polymorphism in the coding or promoter region of the SULT1A1 gene.
15. The method of claim 14 , wherein the polymorphism is selected from the group consisting of SULT1A1 *1, SULT1A1 *2, SULT1A1*3, Arg213His, -624G>C, -396G>A, -358A>C, -341C>G, and -294T>C.
16. The method of claim 15 , wherein the polymorphism is SULT1A1*2.
17. The method of claim 16 , wherein the human subject exhibits the SULT1A1*2 polymorphism, wherein the human subject is prescribed finasteride.
18. The method of claim 16 , wherein the human subject does not exhibit the SULT1A1*2 polymorphism, wherein the androgenetic alopecia treatment excludes any use of topical salicylic acid.