Enzymatic histamine degradation by human skin

Area of Science:

• Biochemistry
• Dermatology
• Enzymology

Background:

• Histamine plays a key role in skin inflammation and allergic reactions.
• Understanding histamine metabolism in the skin is crucial for developing treatments for skin disorders.

Purpose of the Study:

• To investigate the presence and activity of histamine-metabolizing enzymes in human skin.
• To characterize the properties and localization of histamine-N-methyl transferase in skin.

Main Methods:

• In vitro degradation of histamine using homogenized human skin and S-adenosyl methionine.
• Assessing enzyme activity at different temperatures and storage conditions.
• Determining enzyme distribution within skin layers.

Main Results:

• Human skin homogenates degrade histamine via histamine-N-methyl transferase, with optimal activity at 37°C.
• Diamine oxidase shows no significant histamine degradation activity under tested conditions.
• The enzyme is stable in intact skin at -20°C but unstable in homogenized form; activity is low in deeper dermis.

Conclusions:

• Human skin possesses a functional histamine-N-methyl transferase, suggesting a significant histamine-degrading capacity.
• Histamine-N-methyl transferase activity may be a key factor in modulating histamine-mediated skin conditions.
• Further research is needed to clarify the enzyme's precise localization and its role in skin pathophysiology.