Free Radicals and Medicine

Swartz, Harold M.; Mason, Ronald P.; Hogg, Neil; Kalyanaraman, Balaraman; Sarna, Tadeusz; Płonka, Przemysław M.; Zareb, M.; Gutiérrez, Peter L.; Berliner, Lawrence J.

doi:10.1007/0-387-26741-7_3

Cited by 8 publications

(10 citation statements)

References 205 publications

(177 reference statements)

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“…by neurons and immunocytes, while the special connections between melanocytes and keratinocytes (‘pigmentation synapses’) resemble other types of synapses: neuronal, immunological or phagocytic (22). Next, some neurotransmitters and neuromodulators (dopamine) can autooxidate to neuromelanin, a by‐product of their oxidative catabolism in locus coeruleus and substantia nigra (15,29). [In line with this ‘synaptic’ line of argumentation, it deserves at least a footnote that pigmented hair emerged during evolution as sensory organs (tactile mechanoreceptors) (20,21).…”

Section: Viewpoint #2mentioning

confidence: 99%

What are melanocytesreallydoing all day long…?

Płonka

Passeron

Brenner

et al. 2009

Experimental Dermatology

264

242

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Everyone knows and seems to agree that melanocytes are there to generate melanin -an intriguing, but underestimated multipurpose molecule that is capable of doing far more than providing pigment and UV protection to skin (1). What about the cell that generates melanin, then? Is this dendritic, neural crestderived cell still serving useful (or even important) functions when no-one looks at the pigmentation of our skin and its appendages and when there is essentially no UV exposure? In other words, what do epidermal and hair follicle melanocytes do in their spare time -at night, under your bedcover? How much of the full portfolio of physiological melanocyte functions in mammalian skin has really been elucidated already? Does the presence or absence of melanoctyes matter for normal epidermal and ⁄ or hair follicle functions (beyond pigmentation and UV protection), and for skin immune responses? Do melanocytes even deserve as much credit for UV protection as conventional wisdom attributes to them? In which interactions do these promiscuous cells engage with their immediate epithelial environment and who is controlling whom? What lessons might be distilled from looking at lower vertebrate melanophores and at extracutaneous melanocytes in the endeavour to reveal the 'secret identity' of melanocytes? The current Controversies feature explores these far too infrequently posed, biologically and clinically important questions. Complementing a companion viewpoint essay on malignant melanocytes (2), this critical re-examination of melanocyte biology provides a cornucopia of old, but underappreciated concepts and novel ideas on the slowly emerging complexity of physiological melanocyte functions, and delineates important, thought-provoking questions that remain to be definitively answered by future research. Praeludium pigmentosumFor those uninformed, the skin is an inert plastic wrap nature provides to keep us in and everything else out. How mistaken they are! The skin, in particular the epidermis, is one of the most active of all tissues ⁄ organs.Nature wisely placed the capillary circulation in the dermis. The epidermis has no vascular circulation thereby minimizing the probability that toxic chemicals, bacteria or fungi that penetrate through the stratum corneum can diffuse into the blood stream. That does not leave the epidermis defenseless. The epidermis has proteins called defensins that have anti-microbial properties. There are Toll-like receptors that recognize invading organisms and incite a host response. Even more interesting, it is well known that keratinocytes are avidly phagocytic. They have the capacity to phagocytize the wandering, invasive fungi or bacteria and digest them. It is both interesting and important that a-MSH stimulates the ingestion of candida by keratinocytes. a-MSH has a wide array of activities, only one of which is to stimulate the synthesis of melanin. There are receptors for a-MSH on Langerhans cells and keratinocytes as well as melanocytes. It has the ability to suppress infla...

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Section: Viewpoint #2mentioning

confidence: 99%

What are melanocytesreallydoing all day long…?

Płonka

Passeron

Brenner

et al. 2009

Experimental Dermatology

264

242

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“…To the first two groups belong paramagnetic substances produced by one‐electron reduction/oxidation (Fig. 1a) during mitochondrial respiration (1,2), synthesis of deoxyribonucleotides (3) or inflammation (33,34,36), with the engagement of enzymes containing paramagnetic metal ions (2,3,34,36). Such free radicals, generated in the processes crucial to the phenomenon of life, may also be responsible for oxidative stress (33) leading to serious skin pathologies (34).…”

Section: Skin As a Materials For Epr Measurementmentioning

confidence: 99%

“…Various free radicals originate in the skin during redox reactions of a single electron transfer in oxidative respiration or in oxygen burst (33,34). The most important superoxide radical anion (O 2 ˙ − ) produced by NADPH oxidase (36) may be further reduced to the extremely active hydroxyl radical (˙OH) via diamagnetic hydrogen peroxide (75,76) in iron‐catalysed reaction described by Fenton (77) and further by Haber and Weiss (78).…”

Section: Key Problems In Skin Research As Targets Of Epr Techniquesmentioning

confidence: 99%

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Electron paramagnetic resonance as a unique tool for skin and hair research

Płonka

2009

Experimental Dermatology

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Electron paramagnetic resonance (EPR) spectroscopy and imaging (EPRI) are deeply rooted in the basic and quantum physics, but the spectrum of their applications in modern experimental and clinical dermatology and cosmetology is surprisingly wide. The main aim of this review was to show the physical foundation, technical limitations and versatility of this method in skin studies. Free radical and metal ion detection, EPR dosimetry, melanin study, spin trapping, spin labelling, oximetry and NO-metry, EPR imaging, new generation methods of EPR and EPR ⁄ NMR hybrid technology used under ex vivo and in vivo regime are portrayed in the context of clinical and experimental skin research to study problems such as oxidative and nitrosative stress generated by UV or inflammation, skin oxygenation, hydration of corneal layer of epidermis, transport and metabolism of drugs and cosmeceutics, skin carcinogenesis, skin tumors and many others. A part of the paper is devoted to hair and nail research. The review of dermatological applications of EPR is supplemented with a handful of advice concerning practical aspects of EPR experimentation and usage of EPR reagents.

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“…drugs; Wilczok et al, 1990;Slominski et al, 2009) or metal ions (e.g. iron with its ability to drive Fenton reaction) Swartz et al, 2005;Shamoto-Nagai et al, 2006;Rozanowski et al, 2008). Anyway, it is not possible to unambiguously state whether the "melanin debris" of the old ani-mals appears only in the "post-melanotic" spleens, or it can be present as the only manifestation of melanosis in some other, macroscopically non-melanotic spleens.…”

Section: Melanin Degradation In C57bl/6 Animalsmentioning

confidence: 99%

Extradermal melanin transfer? Lack of macroscopic spleen melanization in old C57BL/6 mice with de-synchronized hair cycle.

Michalczyk

Popik²,

Salwinski³

et al. 2009

Acta Biochim Pol

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In quest of alternate, extradermal path of melanin transfer from skin to the visceral organs, we suggested that some portions of such melanin may be deposited in the spleen, which in young black C57BL/6 mice is often melanized. Here, we confirm these observation using young C57BL/6 female mice (up to 17 weeks) and show that this phenomenon cannot be observed in old animals where the hair cycle is not synchronized any more. The experiments were carried out both on spontaneous and depilation-induced hair cycle. We have checked it as a side-observation over many other experiments carried out on young and old C57BL/6 female mice (up to 2.5 years of life). The presence or absence of melanin in the spleens was checked macroscopically, and histologically by Fontana-Masson (FM) staining, and synchronization of the hair cycle - by standard histomorphometric analysis of the back skin hair follicles. In about 40% of old spleens black FM-stainable "debris" could be found under closer histological examination. This study shows that, at least in part, the phenomenon of splenic melanosis in C57BL/6 mice can be correlated with the synchronized skin melanization parallel to the hair cycle progress, and that splenic melanin undergoes gradual degradation during the mouse life.

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Free Radicals and Medicine

Cited by 8 publications

References 205 publications

What are melanocytesreallydoing all day long…?

What are melanocytesreallydoing all day long…?

Electron paramagnetic resonance as a unique tool for skin and hair research

Extradermal melanin transfer? Lack of macroscopic spleen melanization in old C57BL/6 mice with de-synchronized hair cycle.

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