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A multimodal assessment of melanin and melanocyte activity in abnormally pigmented hypertrophic scar.

MedStar author(s):

Citation: Journal of Burn Care & Research. 36(1):77-86, 2015 Jan-Feb.PMID: 25162947Institution: MedStar Washington Hospital CenterDepartment: Surgery/Burn ServicesForm of publication: Journal ArticleMedline article type(s): Journal Article | Research Support, N.I.H., Extramural | Research Support, Non-U.S. Gov'tSubject headings: *Cicatrix, Hypertrophic/me [Metabolism] | *Cicatrix, Hypertrophic/pa [Pathology] | *Hyperpigmentation/me [Metabolism] | *Hypopigmentation/me [Metabolism] | *Melanins/me [Metabolism] | *Melanocytes/ph [Physiology] | alpha-MSH/me [Metabolism] | Animals | Cicatrix, Hypertrophic/et [Etiology] | Disease Models, Animal | Hyperpigmentation/et [Etiology] | Hyperpigmentation/pa [Pathology] | Hypopigmentation/et [Etiology] | Hypopigmentation/pa [Pathology] | Male | Swine | Wound Healing/ph [Physiology]Year: 2015 Local holdings: Available online through MWHC library: 2006 - present, Available in print through MWHC library: 2006 - presentISSN:

1559-047X

Name of journal: Journal of burn care & research : official publication of the American Burn AssociationAbstract: Using a validated swine model of human scar formation, hyperpigmented and hypopigmented scar samples were examined for their histological and optical properties to help elucidate the mechanisms and characteristics of dyspigmentation. Full-thickness wounds were created on the flanks of red Duroc pigs and allowed to heal. Biopsies from areas of hyperpigmentation, hypopigmentation, and uninjured tissue were fixed and embedded for histological examination using Azure B and primary antibodies to S100B, HMB45, and alpha-melanocyte-stimulating hormone (alpha-MSH). Spatial frequency domain imaging (SFDI) was then used to examine the optical properties of scars. Hyperpigmentation was first noticeable in healing wounds around weeks 2 to 3, gradually becoming darker. There was no significant difference in S100B staining for the presence of melanocytes between hyperpigmented and hypopigmented scar samples. Azure B staining of melanin was significantly greater in histological sections from hyperpigmented areas than in sections from both uninjured skin and hypopigmented scar (P < .0001). There was significantly greater staining for alpha-MSH in hyperpigmented samples compared with hypopigmented samples (P = .0121), and HMB45 staining was positive for melanocytes in hyperpigmented scar. SFDI at a wavelength of 632 nm resulted in an absorption coefficient map correlating with visibly hyperpigmented areas of scars. In a red Duroc model of hypertrophic scar formation, melanocyte number is similar in hyperpigmented and hypopigmented tissues. Hyperpigmented tissues, however, show a greater amount of melanin and alpha-MSH, along with immunohistochemical evidence of stimulated melanocytes. These observations encourage further investigation of melanocyte stimulation and the inflammatory environment within a wound that may influence melanocyte activity. Additionally, SFDI can be used to identify areas of melanin content in mature, pigmented scars, which may lead to its usefulness in wounds at earlier time points before markedly apparent pigmentation abnormalities.All authors: Ghassemi P, Jordan MH, Moffatt LT, Paul DW, Prindeze NJ, Ramella-Roman JC, Shupp JW, Travis TEFiscal year: FY2016Digital Object Identifier:

http://dx.doi.org/10.1097/BCR.0000000000000154

Date added to catalog: 2016-01-13

Holdings ( 1 )
Title notes ( 3 )

Holdings
Item type	Current library	Collection	Call number	Status	Date due	Barcode
Journal Article	MedStar Authors Catalog	Article	25162947	Available		25162947

Available online through MWHC library: 2006 - present, Available in print through MWHC library: 2006 - present

Using a validated swine model of human scar formation, hyperpigmented and hypopigmented scar samples were examined for their histological and optical properties to help elucidate the mechanisms and characteristics of dyspigmentation. Full-thickness wounds were created on the flanks of red Duroc pigs and allowed to heal. Biopsies from areas of hyperpigmentation, hypopigmentation, and uninjured tissue were fixed and embedded for histological examination using Azure B and primary antibodies to S100B, HMB45, and alpha-melanocyte-stimulating hormone (alpha-MSH). Spatial frequency domain imaging (SFDI) was then used to examine the optical properties of scars. Hyperpigmentation was first noticeable in healing wounds around weeks 2 to 3, gradually becoming darker. There was no significant difference in S100B staining for the presence of melanocytes between hyperpigmented and hypopigmented scar samples. Azure B staining of melanin was significantly greater in histological sections from hyperpigmented areas than in sections from both uninjured skin and hypopigmented scar (P < .0001). There was significantly greater staining for alpha-MSH in hyperpigmented samples compared with hypopigmented samples (P = .0121), and HMB45 staining was positive for melanocytes in hyperpigmented scar. SFDI at a wavelength of 632 nm resulted in an absorption coefficient map correlating with visibly hyperpigmented areas of scars. In a red Duroc model of hypertrophic scar formation, melanocyte number is similar in hyperpigmented and hypopigmented tissues. Hyperpigmented tissues, however, show a greater amount of melanin and alpha-MSH, along with immunohistochemical evidence of stimulated melanocytes. These observations encourage further investigation of melanocyte stimulation and the inflammatory environment within a wound that may influence melanocyte activity. Additionally, SFDI can be used to identify areas of melanin content in mature, pigmented scars, which may lead to its usefulness in wounds at earlier time points before markedly apparent pigmentation abnormalities.

English