Hydrogen Sulfide (H2S) is a gasotransmitter which is found to be increased in the inflammation response, but we don’t know if it exacerbates it or keeps it in check.
We have no idea whether H2S is an inducer (LINK) or a reliever of itch (LINK). It’s probably as complicated as defining H2S as the chicken or the egg !
But as in itch in general, it is shown here to play a role in the itch found in atopic dermatitis (AD).
Research part 1
H2S is produced by 3 enzymes: cysthathionine beta-synthase (CBS), cysthathionine gamma-lyase (CSE) and mercaptopyruvate sulfur-transferase (MPST)
Results
- -All 3 enzymes were found in human Keratinocytes (in vitro) and increased in AD lesional skin vs health controls.
- -H2S was similarly increased in the blood (enzyme-linked immunoassay).
Research part 2
AD shows epidermal hyperinnervation which is dependent on balance between:
…nerve elongation factors on one hand:
- -Nerve Growth Factor (NGF)
- -Artemin (ARTN)
…and nerve repulsion factors on the other:
- -semaphorin 3A (Sema 3A)
Results
mRNA analysis from public databases (GSE36842, 5667 and 32924):
- -CBS is positively correlated with NGF
- -CSE is correlated NGF and ARTN
Adding H2S through simulation increases mRNA and protein levels of NGF and ARTN (Sema3A remaining unchanged)
Conclusion: H2S likely plays a role in AD induced-hypersensitivity, it does so by acting upon nerve elongation factors.
Reference: Sagita Moniaga C et al. Hydrogen Sulfire may modulate itch of human atopic dermatitis through alteration of nerve elongation factors.The 44th Annual Meeting of the Japanese Society for Investigative Dermatology (2019, November). Aomori-Japan
