Hyaluronan exists in the normal stratum corneum.

Area of Science:

• Biochemistry
• Dermatology
• Extracellular Matrix Biology

Background:

• Hyaluronan (HA) is a key component of the extracellular matrix, primarily known for its water-sorbing properties.
• Its presence and function within the stratum corneum, the outermost layer of the skin, remain less understood.

Purpose of the Study:

• To investigate the presence and characteristics of hyaluronan in the normal mouse stratum corneum.
• To determine the origin and potential functions of hyaluronan in this skin layer.

Main Methods:

• Quantification of hyaluronan content in mouse skin layers (stratum corneum, epidermis, dermis) using high-performance liquid chromatography.
• In vitro organ culture of mouse skin labeled with [3H]-glucosamine to track hyaluronan synthesis, accumulation, and molecular mass.

Main Results:

• Hyaluronan was detected in the normal mouse stratum corneum at a concentration of 22.3 +/- 2.9 microg/g dry weight.
• [3H]-labeled hyaluronan accumulated linearly in the stratum corneum over a 3-day culture period.
• The molecular mass of hyaluronan in the stratum corneum was significantly lower (<6.0 x 10^4) compared to the dermis (>1.0 x 10^6).

Conclusions:

• Hyaluronan is confirmed to be present in the normal stratum corneum, supplied by underlying keratinocytes.
• Hyaluronan in the stratum corneum may contribute to skin moisturization and regulation of mechanical properties.