Comparative Analysis of Type I Keratin Expression By Nail Consistency: An Immunohistochemistry Study

Abstract

The nail plate is one of the essential structures of the nail apparatus and is highly keratinized, making it difficult to handle this tissue experimentally. Different types of nail consistency were identified by applying distal pressure to the nail plate. To analyze the relationship between the keratins expressed in the nail plate and nail consistency, we chose a sample of 32 adult individuals (age 49.81 ± 3.21 y) with the same number of each sex, who had a similar percentage of nail consistency types (56.25% hard consistency nails and 43.75% soft consistency nails). Immunohistochemical analyses showed that hard consistency nails contain more keratin 17 than soft consistency nails (P = 0.026). These novel results allow nail consistency to be defined by the differential expression of keratins in the nail plate, and have potential clinical implications for the diagnosis of possible nail disorders and/or systemic disease.

Lgr6-expressing functional nail stem-like cells differentiated from human-induced pluripotent stem cells

“…In contrast, Lgr6 expression gradually and continuously increased with differentiation. The expression of typical nail keratin, KRT17 (type I; KRT17 is also known as CK-17, PCHC1) [ 40 ] and KRT81 (type II; also known as hHb1, MLN137, ghHkb1, hHAKB2-1) [ 41 ], gradually increased with differentiation.…”

“…KRT17 is also known as CK-17, PCHC1) [40] and KRT81 (type II; also known as hHb1, MLN137, ghHkb1, hHAKB2-1) [41], gradually increased with differentiation.…”

Ultrasound clinical references of the healthy toenail unit

“…It is logical to consider that soft consistency nails are more adaptable, making their curvature less pronounced. For medium and hard consistency nails, the different amounts and types of keratins present (Mingorance Álvarez, Martínez Quintana, et al, 2022; Mingorance Álvarez, Rodríguez‐León, et al, 2022) may explain the lower adaptability and greater curvature. A relationship has been demonstrated between hard nail consistency and a greater prevalence of onychocryptosis (Pérez Pico et al, 2017).…”

“…The nail unit, commonly known as the nail, is a highly keratinized cutaneous appendage located dorsally and distally in the fingers and toes (Mingorance Álvarez, Martínez Quintana, et al, 2022; Mingorance Álvarez, Rodríguez‐León, et al, 2022; Saito et al, 2015). Rather than acting as a merely aesthetic structure of human anatomy, the nail unit has essential functions such as regulating temperature in the distal end of fingers and toes, protecting the phalanges, and increasing the area of toe‐ground contact, thus improving stability and facilitating gait (García et al, 2015).…”