Effect of the lactic acid bacterium Streptococcus thermophilus on ceramide levels in human keratinocytes in vitro and stratum corneum in vivo

J Invest Dermatol. 1999 Jul;113(1):98-106. doi: 10.1046/j.1523-1747.1999.00633.x.


The effects of Streptococcus thermophilus on ceramide levels either in vitro on cultured human keratinocytes or in vivo on stratum corneum, have been investigated. In vitro, Streptococcus thermophilus enhanced the levels of ceramides in keratinocytes in a time-dependent way. The presence of high levels of neutral, glutathione-sensitive, sphingomyelinase in Streptococcus thermophilus could be responsible for the observed ceramide increase. The application of a base cream containing sonicated Streptococcus thermophilus in the forearm skin of 17 healthy volunteers for 7 d also led to a significant and relevant increase of skin ceramide amounts, which could be due to the sphingomyelin hydrolysis through bacterial neutral sphingomyelinase. Indeed, similar results were obtained with a base cream containing purified bacterial neutral sphingomyelinase. In addition, the inhibition of bacterial neutral sphingomyelinase activity through glutathione blocked the skin ceramide increase observed after the treatment. The topical application of a sonicated Streptococcus thermophilus preparation, leading to increased stratum corneum ceramide levels, could thus result in the improvement of lipid barrier and a more effective resistance against xerosis.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Cell Extracts / pharmacology
  • Cell Line
  • Ceramides / metabolism*
  • Cholesterol / metabolism
  • Double-Blind Method
  • Epidermis / drug effects*
  • Epidermis / metabolism
  • Female
  • Humans
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism
  • Lactic Acid / metabolism
  • Lipid Metabolism
  • Male
  • Middle Aged
  • Oxidoreductases / metabolism
  • Skin / drug effects
  • Skin / metabolism
  • Sphingomyelin Phosphodiesterase / metabolism
  • Sphingomyelin Phosphodiesterase / pharmacology*
  • Sphingomyelins / metabolism
  • Streptococcus / enzymology*
  • Streptococcus / metabolism
  • Treatment Outcome


  • Cell Extracts
  • Ceramides
  • Sphingomyelins
  • Lactic Acid
  • Cholesterol
  • Oxidoreductases
  • dihydroceramide desaturase
  • Sphingomyelin Phosphodiesterase