Is Aquaporin-3 a Determinant Factor of Intrinsic and Extrinsic Aging? An Immunohistochemical and Morphometric Study

Abstract

Aquaporin-3 (AQP3) is an aquaglyceroporin that plays a role in skin hydration, cell proliferation, and migration. The aim of this work was to investigate the expression of AQP3 in sun-exposed and sun-protected human skin from different age groups to understand the relationship between AQP3 and skin aging. Using standard immunohistochemical techniques, sun-exposed and sun-protected skin biopsies were taken from 60 normal individuals. AQP3 was expressed in the basal and the suprabasal layers, sparing the stratum corneum, in all specimens. Dermal expression was detected in fibroblasts, endothelial cells, and adnexa. Sun-protected skin showed a significantly higher epidermal H-score and percentage of expression (P=0.002 and <0.001, respectively) compared with sun-exposed skin. The AQP3 expression intensity showed a gradual decrease from the 20 to 35-year-old group to the 35 to 50-year-old group, with the least immunoreactivity in the above 50-year-old group. A significant difference was detected in the H-score in favor of the 20 to 35-year-old group in sun-exposed and sun-protected skin (P<0.001 for both). A significant negative correlation was noted between the AQP3 expression percentage and the age in sun-exposed (r=-0.64, P<0.001) and sun-protected skin (r=-0.53, P<0.001). In conclusion, the skin dryness observed in intrinsic and extrinsic aged skin may be explained, at least in part, by AQP3 downregulation. This may open new avenues sufficient to control skin texture and beauty. Its interaction in skin protein organization and gene polymorphism can also be tackled in future research. In addition, clinical trials using AQP3 topical applications should be carried out to evaluate its effectiveness in the reversal of age-related skin changes.

Aquaporin Membrane Channels in Oxidative Stress, Cell Signaling, and Aging: Recent Advances and Research Trends

“…Accordingly, severe ultraviolet A (UVA) irradiation causes a significant reduction in AQP3 expression secondary to increased oxidative stress [ 65 ]. In this regard, a negative correlation between AQP3 expression and age in sun exposed skin has been described, suggesting AQP3 as a biomarker of age-related skin alteration [ 66 ].…”

Seasonal and Ageing‐Depending Changes of Aquaporins 1 and 9 Expression in the Genital Tract of Buffalo Bulls (Bubalus bubalis)

“…To the best of our knowledge, this is the first time that epididymal age-related change in the expression of AQP has been detected. Altered expression of AQPs during the aging has been reported in other mammalian tissues such as kidney (Combet et al 2008), intervertebral disc (Tas ß et al 2012), cerebrum (Su et al 2013) and skin (Seleit et al 2015).…”

“…This aquaporin was inconstantly seen in the long microvilli of the principal cells in the corpus during the mating season when they strongly expressed AQP9 on the apical surface of the intraepithelial crypts. The presence of this kind of 'cavities' lined by principal cells with long microvilli projecting into the lumen of the cavity is peculiar of the epididymis of some domestic mammals, such as cattle (Nicander 1958;Sinowatz et al 1981), cat (Arrighi et al 1986) or equines (Arrighi et al 1993). The extensive presence of intraepithelial crypts during the buffalo mating season could depend on the necessity to sustain an enhanced epithelial activity than in the resting period.…”

Epidermal aquaporin‐3 downexpression in symmetrical acrokeratoderma

“…3,8 However, skin dryness in intrinsic and extrinsic aged skin may be at least in part due to AQP3 downregulation. 5 AQP3 expression and skin hydration were reduced, and TEWL was elevated in lesional and perilesional skin of psoriasis. 2 Similarly, AQP3 expression was decreased in lesional and perilesional skin of SAK, which is coincident with lessened skin hydration and enhancive TEWL in SAK lesion.…”