Pyrrolidone carboxylic acid may be a key cutaneous biomarker

PCA as a biomarker

In 2009, Kezic et al. determined that the use of tape stripping to cull PCA in the stratum corneum was effective in revealing that PCA concentration in the outermost skin layer is a viable biomarker of filaggrin genotype.¹²

Raj et al. conducted an interesting study in 2016 in which they set out to describe the various markers for total NMF levels and link them to the activities of plasmin and corneocyte maturation in the photoexposed cheek and photoprotected postauricular regions of healthy white, black African, and albino African women in South Africa. PCA levels were highest among the albino African group, followed by black African and then white participants. The investigators also found that bleomycin hydrolase was linked to PCA synthesis, as suggested by higher bleomycin levels in albino African participants. In this group, corneocyte maturation was also observed to be impeded.¹³

The next year, the same team studied stratum corneum physiology and biochemistry of the cheeks in 48 white women with sensitive skin. The goal was to ascertain the connections between bleomycin hydrolase and calpain-1, PCA levels, corneocyte maturation, and transglutaminase and plasmin activities. Capsaicin sensitivity was observed in 52% of subjects, with PCA levels and bleomycin hydrolase activity found to be lower in the capsaicin-sensitive panel and correlated in subjects not sensitive to capsaicin. The researchers concluded that reduced levels of PCA, bleomycin hydrolase, and transglutaminase combined with a larger volume of immature corneocytes suggest comparatively poor stratum corneum maturation in individuals with sensitive skin.¹⁴

Other uses

In 2012, Takino et al. used cultured normal human dermal fibroblasts to show that zinc l-pyrrolidone carboxylate blocked UVA induction of activator protein-1, diminished matrix metalloproteinase-1 synthesis, and spurred type I collagen production. The researchers suggested that such results suggest the potential of zinc PCA for further investigation as an agent to combat photoaging.⁷

Conclusion

Pyrrolidone carboxylic acid is clearly established as the main component of the NMF. Recent research suggests that it may serve as an important biomarker of filaggrin, NMF levels, and skin hydration. In addition, new data point to its usefulness as a gauge for ADs. More investigations are necessary to ascertain the feasibility of adjusting PCA levels through topical administration and what effects topically applied PCA may have on various skin parameters.

Dr. Baumann is a private practice dermatologist, researcher, author, and entrepreneur in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote two textbooks, “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002) and “Cosmeceuticals and Cosmetic Ingredients” (New York: McGraw-Hill, 2014), as well as a New York Times Best Sellers book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). Dr. Baumann has received funding for advisory boards and/or clinical research trials from Allergan, Evolus, Galderma, and Revance. She is the founder and CEO of Skin Type Solutions Franchise Systems LLC. Write to her at dermnews@mdedge.com.

References

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4. Kwoya Hakko Kogyo Co. Pyrrolidone carboxylic acid esters containing composition used to prevent loss of moisture from the skin. Patent JA 48 82 046 (1982).

5. Org Santerre. l-pyrrolidone carboxylic acid-sugar compounds as rehydrating ingredients in cosmetics. Patent Fr 2 277 823 (1977).

6. Clar EJ, Fourtanier A. Int J Cosmet Sci. 1981 Jun;3(3):101-13.

7. Takino Y et al. Int J Cosmet Sci. 2012 Feb;34(1):23-8.

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13. Raj N et al. Int J Cosmet Sci. 2016 Dec;38(6):567-75.

14. Raj N et al. Int J Cosmet Sci. 2017 Feb;39(1):2-10.