Age-Related Hair Pigment Loss

Tobin, Desmond J.

doi:10.1159/000369413

Cited by 25 publications

(23 citation statements)

References 79 publications

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“…However, it is worth pointing out that for greying of hair or vitiligo, conditions that are associated with the loss of pigmentation, the presence of increased levels of H 2 O 2 has been discussed as a potential contributing factor to these changes in pigmentation. [44][45][46] Our current and previous observations [14][15][16] do suggest a hypothesis that the absence of dark colors may not necessarily mean the absence of MN-like molecules, but could mean the presence of a different type of MN-like material. It is worth pointing out that the light-colored MN-like materials generated in the presence of high concentrations of H 2 O 2 do absorb or scatter light in the UV range of the electromagnetic spectrum, although to a less efficient extent than the dark-colored materials.…”

Section: Discussionmentioning

confidence: 62%

Light- or Dark-Colored, L-DOPA-Based Melanins

Vercruysse¹,

Whalen²

2018

Preprint

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This report is a continuation of previous research on the H 2 O 2 -mediated synthesis of melanin-like pigments. We synthesized and characterized L-DOPA-based pigments using air-or H 2 O 2 -mediated oxidation. We compared their physic-chemical properties and evaluated their capacity to affect the interleukin release from immune cells. The use of higher concentrations of H 2 O 2 resulted in melanin-like materials with a distinct chemical signature in their FT-IR spectra and a lighter color. All pigments enhanced the interleukin release from immune cells. The possibility that lighter-colored melanins can be generated is discussed in the context of the importance of melanin-based pigmentation in human physiology.

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Section: Discussionmentioning

confidence: 62%

Light- or Dark-Colored, L-DOPA-Based Melanins

Vercruysse¹,

Whalen²

2018

Preprint

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“…However, it is worth pointing out that for greying of hair or vitiligo, conditions that are associated with the loss of pigmentation, the presence of increased levels of H 2 O 2 has been discussed as a potential contributing factor to these changes in pigmentation. [40][41][42] In addition, the importance of H 2 O 2 in the process of melanogenesis has been discussed before. [24] Our current and previous observations [17,18] do suggest a hypothesis that the absence of dark colors may not necessarily mean the absence of MN-like molecules, but could mean the presence of a different type of MN-like material.…”

Section: Discussionmentioning

confidence: 99%

Synthesis of L-DOPA based pigments with different physic-chemical properties

Vercruysse¹

2018

Preprint

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Using air- or Fe2+/H2O2-mediated oxidation, the formation of melanin-like pigments from L-DOPA was evaluated. The effects of the various reaction conditions on the efficiency of the reaction and the physic-chemical properties of the pigments generated (UV-Vis absorbance, fluorescence emission) was evaluated. As previously observed for other phenolic and indolic compounds, the use of high concentrations of H2O2 resulted in melanin-like materials with a much lighter color. In addition, we observed that, unlike for air-mediated oxidation, the Fe2+/H2O2-mediated oxidation of L-DOPA can yield melanin-like pigmentation in an acidic environment. In general, our results suggest that depending on the intensity of the oxidizing reaction conditions involved, light- or dark-colored melanin-like pigments can be generated from L-DOPA. This may be an important factor when evaluating the visible outlook of histological specimens: the presence of a lighter color or the absence of a dark color may not necessarily mean the absence of melanin-like biomolecules. We discuss all our observations in the context of the importance of melanin-like pigmentation in human physiology.

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“…[17,18] It is interesting to compare the relationship between AKU and ochronosis and other conditions or diseases that involve changes in pigmentation: vitiligo or greying of hair. [19,20] For both, an increased level of H 2 O 2 has been discussed a potential contribution factor to the changes in pigmentation. [9,10] In this respect is worth noting that HGA can auto-oxidize and produce ROS like H 2 O 2 .…”

Section: Discussionmentioning

confidence: 99%

“…[21] Although the effect of age on pigmentation in AKU (from colorless to darkly colored) is the reverse as that for aging hair (from darkly colored to lighter colored), we can expand our comparison between ochronosis and greying of hair by noting that, with regard to the biochemical and physiological changes in hair, the third decade is considered to be a pivot point. [20] Both pathologies are also associated with a compromised ability to defend against ROS. [22][23][24] The pigmentation associated with AKU and ochronosis is derived from HGA, while other precursors, cateholamines or DOPA, form the basis for the pigmentation associated with vitiligo or hair color.…”

Section: Discussionmentioning

confidence: 99%

Fe²⁺/H₂O₂-mediated oxidation of homogentisic acid indicates the production of ochronotic and non-ochronotic pigments. Implications in Alkaptonuria and beyond

Vercruysse

Taylor

Knight

2017

Preprint

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Homogentisic acid (HGA) can be oxidized by a combination of Fe 2+ and H 2 O 2 into a darkly colored high molecular mass pigment. Increasing the concentration of H 2 O 2 can lead to the formation of a high molecular mass material that exhibits less absorbance in the visible range of the electromagnetic spectrum, while maintaining a strong absorbance in the UV range of the electromagnetic spectrum. FT-IR spectroscopy did indicate the presence of a chemical feature in the pigments generated through H 2 O 2 -mediated oxidation that is absent in pigments generated through air-mediated oxidation. Our observations could have implications in the pathophysiology of alkaptonuria. In alkaptonuria, patients suffer from homogentisic aciduria from birth, but develop ochronosis (darkening) of collagenous tissues much later in life due to the formation of a melanin-like pigment. Three major questions regarding ochronosis remain to be answered: 1) how is the pigment formed, 2) why does it appear by the third decade of life and 3) why is it sporadic in appearance? Our results suggest that ochronotic or non-ochronotic pigments can be generated from HGA depending on the oxidation reaction conditions. Thus, the absence of any visible pigment, as for younger alkaptonuria patients, could not necessarily mean the absence of HGA-derived melanin-like molecules. We compare our results and their potential implications for ochronosis to the changes in pigmentation observed in vitiligo or aging (greying) hair.

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Age-Related Hair Pigment Loss

Abstract: Bradford Scholars -how to deposit your paper Overview Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.

Cited by 25 publications

References 79 publications

Light- or Dark-Colored, L-DOPA-Based Melanins

Light- or Dark-Colored, L-DOPA-Based Melanins

Synthesis of L-DOPA based pigments with different physic-chemical properties

Fe²⁺/H₂O₂-mediated oxidation of homogentisic acid indicates the production of ochronotic and non-ochronotic pigments. Implications in Alkaptonuria and beyond

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Age-Related Hair Pigment Loss

Abstract: Bradford Scholars -how to deposit your paper Overview Copyright check• Check if your publisher allows submission to a repository.• Use the Sherpa RoMEO database if you are not sure about your publisher's position or email openaccess@bradford.ac.uk.

Cited by 25 publications

References 79 publications

Light- or Dark-Colored, L-DOPA-Based Melanins

Light- or Dark-Colored, L-DOPA-Based Melanins

Synthesis of L-DOPA based pigments with different physic-chemical properties

Fe2+/H2O2-mediated oxidation of homogentisic acid indicates the production of ochronotic and non-ochronotic pigments. Implications in Alkaptonuria and beyond

Contact Info

Product

Resources

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Fe²⁺/H₂O₂-mediated oxidation of homogentisic acid indicates the production of ochronotic and non-ochronotic pigments. Implications in Alkaptonuria and beyond