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. 2021 Jun 22;10:e67437. doi: 10.7554/eLife.67437

Figure 2. Reversal of hair greying across ages and body regions.

(A–G) Examples of HS greying and reversal including schematic of hair growth (top left), digitized HPP (top right), and light microscopy images (bottom) corresponding to numbered HS segments on the HPP plot. (A) Examples illustrating the reversal of greying along the length of scalp, (B) pubic, (C), and beard human HSs. (D) Example of segmental HS with double transitions, including temporary greying and (E) temporary reversal from an adult and a child, respectively. See Figure 2—figure supplement 1 for additional examples and Video 1 for animation. (F) Time course diagram illustrating the progression of a single dark HS undergoing greying followed by reversal back to its original color, and (G) closely occurring events of greying and reversal occurring, producing HS with double transitions. (H) Average maximum and minimum pigmentation intensity among transitioning hairs from participants with two-colored hairs (n = 11). Hairs with an average maximum intensity >180 A.U. are categorized as high intensity (black), 140–180 A.U. as intermediate intensity, and 100–140 A.U. as low intensity (pale color), indicating that these findings generalize across a range of pigmentation densities. (I) Rate of depigmentation per day in greying HS (n = 23), measured from the slope on HPP graphs expressed as % of starting intensity loss per day (assuming growth rate of 1 cm/month). (J) Comparison of the absolute rate of pigmentation change per day in greying (n = 23) and reverted (n = 34) HS. (I) and (J) are reported on a log2 scale to facilitate visualization.

Figure 2—source data 1. Source data for Figure 2.
elife-67437-fig2-data1.xlsx (1,007.7KB, xlsx)

Figure 2.

Figure 2—figure supplement 1. Hair pigmentation patterns across a range of individuals.

Figure 2—figure supplement 1.

(A) Examples of greying reversal in hairs with various rates of re-pigmentation in three adult individuals, including slow, medium, and rapid events of repigmentation. The left side shows actual photographs of hairs and the length over which each hair shaft regains pigmentation. On the right are the corresponding hair pigmentation patterns (HPPs) for each hair and the computed slope reflecting the rate of greying reversal. (B) Quantification of the rate of change in pigmentation per day in greying and reverted hairs (n = 39) and pubic greying and reverted hairs (n = 9), reported on a log2 scale. (C) Examples of hairs undergoing the transition from dark to grey from a 40-year-old female, 35-year-old female, and 69-year-old male. (D) Additional examples of hairs undergoing greying reversal from a 39-year-old male, 36-year-old female, and a 33-year-old male. (E) Additional examples of hairs with double transitions and reversions from a 35-year-old female and a 36-year-old female.
Figure 2—figure supplement 1—source data 1. Source data for Figure 2—figure supplement 1.