corneocytesenucleated

Enucleated corneocytes are the anucleate cells that populate the stratum corneum, the outermost layer of the epidermis. They originate from keratinocytes that undergo terminal differentiation, a process known as cornification, during which the nucleus and most organelles are degraded and ultimately lost. The mature cell is a flattened, keratin-rich corneocyte enclosed by a cross-linked cornified envelope and sits within a lipid-rich intercellular matrix.

During cornification, keratin filaments are reorganized and a robust cornified envelope forms through the cross-linking of structural proteins such as loricrin and involucrin. The plasma membrane is transformed into an insoluble envelope, and extracellular lipid lamellae accumulate between adjacent corneocytes, contributing to the barrier properties of the stratum corneum. The enucleation process results in cells specialized for barrier function rather than metabolic activity.

Function and turnover are centrally related: enucleated corneocytes provide a mechanical barrier to abrasion and a barrier to transepidermal water loss, as well as limiting entry of pathogens and chemicals. Desquamation, the shedding of corneocytes, occurs as corneodesmosomes disassemble and the outermost cell layer is exfoliated.

Clinical relevance is chiefly seen in the contrast with parakeratosis, where nuclei persist in cells of the stratum corneum, signaling disrupted differentiation as seen in conditions such as psoriasis. Abnormalities in corneocyte maturation or desquamation can contribute to xerosis, ichthyosis, and other keratinization disorders. Diagnosis and study typically rely on histology and ultrastructural methods that confirm the enucleated, flattened morphology of mature corneocytes.