• Dao deficiency
• Histamine
• Histamine Intolerance
• UHPLC

Histamine intolerance is a pathological process in which due to the disequilibrium between accumulated histamine and histamine degradation mainly caused by ingestion of food containing high amounts of histamine by people with low intestinal enzyme activity or inhibition of this activity by different causes. It mainly depends on diamine oxidase enzyme and less on histamine- N- methyltransferase and the symptoms are usually very similar to an allergic reaction and affect multiple systems.
The aim of the project is to study the metabolic profile of histamine and methylhistamine in urine and the possible validation to set an alternative for the diagnosis of HIT with DAO deficit less invasive that the one current in use based on plasmatic DAO activity. The initial hypothesis is that people with a lower DAO activity would have a different distribution profile of HA and MHA in urine compared with healthy individuals; patients would show an accumulation of HA as well as a higher level of its major metabolite produced by the HNMT metabolic pathway (methylhistamine) that controls.
First morning hour urine samples from 39 subjects were collected, processed and SPE procedure for samples purification was done. Than UHPLC-FL was used for chromatographic separation of histamine and methylhistamine and, after values extrapolation they have been normalized for creatinine and a comparison between controls and patients data was done.
Through this project it has been shown that controls showed a significant higher level of methylhistamine and a slightly higher value of histamine so the initial hypothesis is not verify but currently used UHPLC-FL analytical method has been shown to be a valid method for de determination of urine histamine and methylhistamine.