The Thyroid Hormone Analogue KB2115 (Eprotirome) Prolongs Human Hair Growth (Anagen) Ex Vivo  Attila Oláh, Jennifer Gherardini, Marta Bertolini, Jérémy Chéret, Leslie Ponce, Jennifer Kloepper, Tamás Bíró, Michael Soeberdt, Christoph Abels, Ralf Paus  Journal of Investigative Dermatology  Volume 136, Issue 8, Pages 1711-1714 (August 2016) DOI: 10.1016/j.jid.2016.03.033 Copyright © 2016 The Authors Terms and Conditions

Figure 1 KB2115 promotes the anagen phase and increases proliferation of matrix keratinocytes in human hair follicles. (a) Results of microscopic hair cycle staging of three independent donors. Ratios of anagen and early, mid-, and late catagen hair follicles were calculated in each case. Data are shown as mean ± standard error of the mean of the three donors. (b) Percentages of proliferating (Ki67+) and apoptotic (TUNEL+) matrix keratinocytes were determined. Data are expressed as mean ± standard error of the mean of n = 36–37 HFs from three donors. ∗P < 0.05 and ∗∗∗P < 0.001 versus control group. (c) Representative pictures of Ki67 (red) and TUNEL (green) double staining after the indicated treatments. Scale bar = 50 μm. Nuclei were counterstained by 4′-6-diamidino-2-phenylindole (DAPI; blue). HF, hair follicle; pM, pmol/L; n.s., not significant. Journal of Investigative Dermatology 2016 136, 1711-1714DOI: (10.1016/j.jid.2016.03.033) Copyright © 2016 The Authors Terms and Conditions

Figure 2 KB2115 tends to increase melanin synthesis, significantly increases tyrosinase activity, and decreases TGF-β2 immunoreactivity. (a, c, e) Signal intensities (determined as arbitrary units) of (a) Masson-Fontana histochemistry, (c) tyrosinase activity assay, and (e) TGF-β2 immunofluorescence were normalized to the control. Data are expressed as mean ± standard error of the mean of (a) n = 37–42, (c) n = 28–39, or (e) n = 29–36 hair follicles of three donors. ∗∗P < 0.01, ∗∗∗P < 0.001 versus control group. (b, d, f) Representative images of (b) Masson-Fontana (black) histochemistry, (d) tyrosinase activity (red) assay, and (f) TGF-β2 (green) immunofluorescence. Nuclei were counterstained by (b) hematoxylin (blue) or by (d, f) 4′-6-diamidino-2-phenylindole (DAPI; blue). Scale bar = 50 μm. MF, Masson-Fontana; n.s., not significant; pM, pmol/L; TGF, transforming growth factor; Tyr, tyrosinase. Journal of Investigative Dermatology 2016 136, 1711-1714DOI: (10.1016/j.jid.2016.03.033) Copyright © 2016 The Authors Terms and Conditions