Genomic expression patterns in medication overuse headaches.
BACKGROUND
Chronic daily headache (CDH) and chronic migraine (CM) are one of the most frequent problems encountered in neurology, are often difficult to treat, and frequently complicated by medication-overuse headache (MOH). Proper recognition of MOH may alter treatment outcome and prevent long term disability.


OBJECTIVE
This study identifies the unique genomic expression pattern MOH that respond to cessation of the overused medication.


METHODS
Baseline occurrence of MOH and typical pattern of response to medication cessation were measured from a large database. Whole blood samples from patients with CM with or without MOH were obtained and their genomic profile was assessed. Affymetrix human U133 plus2 arrays were used to examine the genomic expression patterns prior to treatment and 6-12 weeks later. Headache characterisation and response to treatment based on headache frequency and disability were compared.


RESULTS
Of 1311 patients reporting daily or continuous headaches, 513 (39.1%) reported overusing analgesic medication. At follow-up, 44.5% had a 50% or greater reduction in headache frequency, while 41.6% had no change. Blood genomic expression patterns were obtained on 33 patients with 19 (57.6%) overusing analgesic medication with a unique genomic expression pattern in MOH that responded to cessation of analgesics. Gene ontology of these samples indicated a significant number were involved with brain and immunological tissues, including multiple signalling pathways and apoptosis.


CONCLUSIONS
Blood genomic patterns can accurately identify MOH patients that respond to medication cessation. These results suggest that MOH involves a unique molecular biology pathway that can be identified with a specific biomarker.
University of Cincinnati, OH, USA. Andrew.Hershey@cchmc.org
Andrew D
AD
Hershey
Danny
D
Burdine
Marielle A
MA
Kabbouche
Scott W
SW
Powers
D000293:Adolescent; D000700:Analgesics / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D005260:Female; D020869:Gene Expression Profiling; D005819:Genetic Markers; D023281:Genomics; D020773:Headache Disorders / Q000139:chemically induced / Q000235:genetics; D051271:Headache Disorders, Secondary / Q000235:genetics*; D006801:Humans; D008297:Male; D008881:Migraine Disorders / Q000139:chemically induced / Q000235:genetics
D000700:Analgesics; D005819:Genetic Markers