Insulin‐like growth factor‐1: roles in androgenetic alopecia

Abstract

individuals (11). TEWL has been found to be dependent on the skin surface temperature (12), and both rhythms are modified according to the environmental temperature. The circadian variations in these variables could be due to the rhythm of core body temperature and also to modifications in the degree of dilatation of subcutaneous vascular network. This agrees with the fact that the basal TEWL, in humans, reaches their highest levels around 3:00 h (13), corresponding to the peak in skin surface temperature. TEWL is useful to determine the state of the skin water barrier (14) and it correlates with percutaneous absorption (15). Thus, the knowledge of its circadian rhythm may be useful to deduce the moment of the day at which the barrier is less disrupted and determine the best time of day for testing topical drug delivery. Contrary to TEWL, SCH is a constituent property of the skin structure and thus is not easily modified by external factors such as temperature.Our results also indicate that skin variables depend on the integrity of the circadian pacemaker, because when animal became arrhythmic by exposure to constant light, TEWL and SCH were differently correlated with temperature, suggesting different regulations of both variables.As circadian rhythms may influence skin absorption or the manifestation of skin diseases (psoriasis, atopic dermatitis, etc.), and SCH and TEWL alterations are associated with some skin disorders (16,17), the knowledge of their daily variation could be helpful for results interpretation. In humans, some circumstances may produce loss or attenuation of the circadian rhythms (elderly, jet-lag, shift work or light alterations), which could in turn influence sleep and skin functionality (18). Hairless rats could be a good model to study the skin functional rhythms in situations that generate disruption of circadian rhythms. AcknowledgementsThis work was supported by the Ministerio de Educaci on y ciencia (BFU2008-00199). The authors thank Dr. A.del Pozo for lending the measuring apparatus. All authors designed the experiment and performed the research. AF, ADN and TC analysed the data and wrote the manuscript. Conflict of interestsThe authors state no conflict of interests. Supporting InformationAdditional Supporting Information may be found in the online version of this article: Data S1. Detailed methods and materials. Figure S1. Actogram of a representative animal along the experimental conditions. Figure S2. Daily profiles of the variables in the experimental days. Abstract: Of all the cytokines or growth factors that have been postulated to play a role in hair follicle, insulin-like growth factor-1 (IGF-1) is known to be regulated by androgens. However, how IGF-1 is altered in the balding scalp has not yet been investigated. In this study, expressions of IGF-1 and its binding proteins by dermal papilla (DP) cells obtained from balding versus nonbalding hair follicles were quantified using growth factor array. DP cells from balding scalp follicles were found to secrete significantly l...

Further Clinical Evidence for the Effect of IGF-1 on Hair Growth and Alopecia

“…Alternatively, investigations are conducted on the topical application of IGF-1, inasmuch as dermal papillary cells from balding scalp follicles have been found to secrete less IGF-1 than their counterparts from nonbalding scalp follicles [25]. Moreover, low circulating IGF-1 levels have been associated with hair loss in middle-aged women [26].…”

Enhanced VEGF Expression in Hair Follicle Dermal Papilla Cells by Centella asiatica Linn.

“…Genetic factors, cytokine imbalance, and oxidative stress can cause abnormal hair follicle cycling and subsequent hair loss (Rho et al, 2005;Aron et al, 2013). Many cytokines and receptors are involved in the cell cycle of human follicle dermal papilla cells, including the vascular endothelial cell growth factor (VEGF) (Shin et al, 2014), vascular endothelial cell growth factor receptor (VEGFR) (Li et al, 2012), fibroblast growth factor (FGF) (Rho et al, 2005), insulin-like growth factor (IGF) (Panchaprateep and Asawanonda, 2014), epidermal growth factor (EGF) (Bressan et al, 2014), keratinocyte growth factor (KGF) (Gopu et al, 2015), and transforming growth factor (TGF) (Kang et al, 2013;Shin et al, 2014). Some hair regeneration has been achieved by molecular effect and growth factors (Danilenko et al, 1996) and follicle dermal stem cells (Rahmani et al, 2014).…”

Bioactives in Chinese Proprietary Medicine Modulates 5α-Reductase Activity and Gene Expression Associated with Androgenetic Alopecia

“…IGF-1 is one of the most extensively studied gene for its essential role in hair cycle control as well as hair shaft differentiation during the development of hair follicles. In its absence, anagen hair follicles in organ culture enter the catagen phase (Panchaprateep and Asawanonda, 2014). DPC from balding scalp follicles were found to secrete significantly less IGF-1 as compared to non-balding scalp follicles (Panchaprateep and Asawanonda, 2014).…”

“…In its absence, anagen hair follicles in organ culture enter the catagen phase (Panchaprateep and Asawanonda, 2014). DPC from balding scalp follicles were found to secrete significantly less IGF-1 as compared to non-balding scalp follicles (Panchaprateep and Asawanonda, 2014). This phenomenon was alluded to the prolongation effect of the anagen phase by IGF-1.…”