Characteristics of keratinocytes in facial solar lentigo with flattened rete ridges: comparison with melasma

Abstract

These findings suggest that senescent changes in keratinocytes are important in the development of SL, even in the absence of rete ridge elongation, and the removal of keratinocytes harbouring melanin could be a possible strategy for SL treatment.

Paracrine Factors from Irradiated Peripheral Blood Mononuclear Cells Improve Skin Regeneration and Angiogenesis in a Porcine Burn Model

“…The increased number of rete ridges can also be interpreted as a result of improved epidermal regeneration and proliferation leading to faster protrusion of the epidermal layer into the dermis. Flattened rete ridges are a common finding in solar lentigo 54 . Another issue for burn victims is the high rate of infection after trauma due to the defective or missing skin barrier.…”

Melasma: Updates and perspectives

“…(Table ) The increased length of basal layer rather than melanocyte hyperplasia is thought to contribute to the greater number of melanocytes observed in SL . About half of the SL lesions have flattened epidermis, but epidermal thickening is consistently reported in the SL lesions . Dermal change is rarely observed in SL except for age‐related elastotic changes .…”

Biological processes in solar lentigo: insights brought by experimental models

“…In contrast, using an antibody directed against the transcription factor MIFT (microphthalmia‐associated transcription factor), which is involved in the regulation of melanin synthesis, Shin et al. demonstrated its higher expression in SL lesion as compared to the perilesional skin, strongly suggesting an increased number of melanocytes in SL. Tyrosinase (TYR) and TRP‐1 (tyrosinase‐related protein 1) proteins, which are additional melanocyte markers, were present in higher proportion in SL biopsies as compared to perilesional skin or to non‐lesional skin from healthy controls .…”

“…Numerous immunohistochemistry‐based studies using SL biopsies have qualitatively evaluated the presence of biomarkers specifically associated with different skin layers and involved in the pigmentation process .…”

“…Using two antibodies that recognize epidermal keratinocyte differentiation markers, such as filaggrin and involucrin, histological studies revealed less staining in SL epidermis as compared to adjacent perilesional skin, suggesting an altered cornification process in SL . Recent findings demonstrated that the thicker epidermis observed in SL on the facial skin was explained by a hyperplasia of the keratinocytes that are probably senescent, as suggested by the stronger labelling with the p16 antibody .…”