ABSENCE OF H2O2 BREAKDOWN IN HUMAN HAIR MEDULLA IMPLICATIONS IN FOLLICULAR MELANOGENESIS

The purpose of this manuscript is to introduce the absence of H2O2 decomposition in the human hair follicle medulla. This absence is attributed to an absence of the antioxidants that are essential for the elimination of reactive oxygen species generated during cellular respiration. The present assumption is that the human hair follicle follicular melanogenesis (FM) involves sequentially the melanogenic activity of follicular melanocytes, the transfer of melanin granules into cortical and medulla keratinocytes, and the formation of pigmented hair shafts. The introduction of an airborne gradual hydrogen peroxide (H2O2) molecules transfer into water, has allowed for the slow down of H2O2 decomposition speed when contacting human tissue. The usual explosive reaction commonly seen has been avoided; and previously unseen details of the H2O2 breakdown anatomical locations within the human hair follicle reaction can now be detected. Dynamic videorecordings show for the first time H2O2 decomposition occurring in the cortical and cortex areas. Published evidence links cellular H2O2 breakdown and metabolism. A new paradigm is herein introduced where the human hair medulla is excluded from H2O2 breakdown, thus inferring the absence of metabolic activity from FM. ORCID # 0000-0003-1195-2210


Introduction
The purpose of this communication is to demonstrate for the first time dynamic evidence (via video-recordings) challenging the anatomical sites identified as to where melanogenesis takes place in the human follicle (1). Exogenous (H2O2) molecules decompose when penetrating an injured hair follicle; this breakdown is caused in sites of active metabolism. This manuscript reintroduces a desktop optical microscopy technique (2) developed for the slowing of H2O2 decomposition speed. This allowed for the demonstration (video-recordings) that H2O2 breakdown occurs in the cortical/cortex areas of the hair follicle. There is a noticeable absence of activity (read metabolism) in the medulla (3).

The Human Hair Anatomy
As shown (Figure 1) for the purpose of this presentation, the human hair is anatomically divided into two main components. The inner anatomy of the hair follicle can be appreciated. The image below was obtained by immersing in vitro a scalp human hair (n=2) from a blonde person in liquid Potassium Ferrocyanide (4,5). Attempts to duplicate the experiment failed in gray or dark hairs.

The Injured Hair Root Experiments
Hydrogen Peroxide when poured into a wound emits bubbles. These bubbles are as result of the H2O2 breakdown by the protein enzyme catalase abundantly present in tissue. This reaction causes the H2O2 to decompose into water and oxygen. The hair has been classified as a mini organ with its own circulation, nerve innervation and cellular divisions (6), this entails cellular respiration inducing H2O2 decomposition. Cell respiration entails the elimination of toxic substances, one of them being the endogenously produced H2O2 (7,8). Experimentally, when drops of H2O2 are in contact with plucked hair follicles on a glass slide, there is an explosive reaction seen due to H2O2 breakdown into water and oxygen molecules; therefore this maneuver obscures any time related details of the reaction (Figure 2). In other words, the visual dynamics identifying where the H2O2 molecules travel when penetrating the tissue are difficult to track; this unless the reaction is slowed down. This author theorized that by slowing the H2O2 decomposition reaction, details not   cortex layers of the follicle. The lack of H2O2 decomposition infers a lack of antioxidant presence, thus absence of metabolic activity (read metabolism) (3). Due to its potential effect on melanogenesis these findings support the published theory that endogenous H2O2 produced in millimolar amounts in the hair follicle could be a factor in senile gray hairs. In other words, as we age, our antioxidant mechanism is impaired, thus allowing for hair greying to occur. As aforementioned, the figures and video links below, demonstrate that H2O2 decomposition occurs between the cuticle and the cortex.

Present Paradigm
These findings contradicts the 2005 published paper by Slominski, A. where is stated that "Follicular melanogenesis (FM) involves sequentially the melanogenic activity of follicular melanocytes, the transfer of melanin granules into cortical and medulla keratinocytes, and the formation of pigmented hair shafts". (1).

Proposed New Paradigm
Instead, the data herein presented is in agreement with the physical location of melanin found by pathologists as stated: "The cortex of the hair shaft is located between the hair cuticle and medulla and is the thickest hair layer. It also contains most of the hair's pigment, giving the hair its color. The pigment in the cortex is melanin, which is also found in skin. The distribution of this pigment varies from animal to animal and person to person. In humans, the melanin is primarily denser nearer the cuticle whereas in animals, melanin is primarily denser nearer the medulla" (9); also confirmed by a forensic pathologist "Human hair has a narrow medulla and a thick cortex and the reverse is true for animal hair….In human hair the medulla is narrow and the pigment is concentrated at the periphery of the cortex" (10). The dynamic recordings as presented in four different experiments demonstrate that the H2O2 molecules are broken down between the cuticle and the cortex.

Medical Implications
The technique and results presented could have utility in evaluating hair losing syndromes, such as Alopecia Areata and possibly Telogen Effluvium (11,12) How? By evaluating follicular melanogenesis activity in these syndromes. Additional research is warranted.

Summary
Labeled microphotographs of video-frames are presented. Video-recordings are also available to the reader. By analyzing these images, the presence of oxygen bubbles indicating follicular melanogenesis are now observed occurring in the cuticle/cortex area of the human hair follicle; instead of the cortex/medulla as previously reported. The findings herein presented are supported by independent pathologist. Also confirmed is the theory that oxidative stress (H2O2) is responsible for senile greying (13).