Several studies have demonstrated that
ceramides play an essential role in both the barrier and water-holding functions of healthy stratum corneum, suggesting that the dysfunction of the stratum corneum associated with ageing as well that observed in patients with several
skin diseases could result from a
ceramide deficiency. In a previous study our group reported a significant increase in skin
ceramide levels in healthy subjects
after treatment in vivo with a cream containing a preparation of Streptococcus thermophilus. The presence of high levels of neutral
sphingomyelinase activity in this organism was responsible for the observed increase of stratum corneum
ceramide levels, thus leading to an improvement in barrier function and maintenance of stratum corneum flexibility. The aim of the present work is to investigate the effects of the topical treatment of a Streptococcus thermophilus-containing cream on
ceramide levels of stratum corneum of healthy elderly women. The
ceramide levels, transepidermal water loss and capacitance were evaluated on stratum corneum sheets from the forearms of 20 healthy female subjects treated with a base cream or the same cream containing a sonicated preparation of the
lactic acid bacterium Streptococcus thermophilus. A 2-week topical application of a sonicated Streptococcus thermophilus preparation led to significant and relevant increase of stratum corneum
ceramide levels. Moreover, the hydration values of the treated forearm of each subject was significantly higher than control sites. These results suggest that the experimental cream was able to improve the
lipid barrier and to increase a resistance against ageing-associated xerosis.