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Pathological changes in platelet histamine oxidases in atopic eczema
Mediators of Inflammation
|January 1, 1993
Summary
Atopic eczema (AE) patients show reduced diamine oxidase and monoamine oxidase B activity, linked to higher histamine. Cofactor levels suggest environmental factors or genetics may cause these enzyme deficiencies in AE.
Area of Science:
- Biochemistry
- Dermatology
- Enzymology
Background:
- Atopic eczema (AE) is a chronic inflammatory skin condition.
- Enzyme activity, particularly diamine oxidase (DAO) and monoamine oxidase B (MAO-B), plays a role in biogenic amine metabolism.
- Dysregulation in these enzymes may be implicated in AE pathogenesis.
Purpose of the Study:
- To investigate plasma histamine levels and the activities of DAO and MAO-B in patients with atopic eczema.
- To examine cofactor levels for DAO and MAO-B to understand potential causes of altered enzyme activity.
- To assess levels of various biogenic amines in AE patients.
Main Methods:
- Analysis of plasma histamine levels.
- Measurement of DAO and MAO-B activities in platelet-rich plasma.
- Quantification of cofactor levels (pyridoxal phosphate, Cu(2+), flavin adenine dinucleotide, Fe(2+)).
- Assay of serum and plasma biogenic amine concentrations (putrescine, cadaverine, spermidine, spermine, tyramine, serotonin, dopamine, epinephrine).
Main Results:
- Significantly increased plasma histamine levels were observed in AE patients.
- DAO and MAO-B activities were significantly lowered in AE patients.
- DAO cofactor levels were near normal, while MAO-B cofactors (flavin adenine dinucleotide and Fe(2+)) were reduced.
- Levels of tested biogenic amines in serum and plasma were generally normal.
Conclusions:
- The decreased DAO and MAO-B activities in AE patients are unlikely due to the measured biogenic amines.
- Reduced MAO-B cofactor levels suggest a potential mechanism for enzyme inhibition.
- Environmental factors (nicotine, alcohol, food additives, chemicals) or a genetic defect are proposed as likely causes for DAO inhibition in AE.
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