Medium-mediated effects increase cell killing in a human keratinocyte cell line exposed to solar-simulated radiation

Maguire, Alanna; Morrissey, Brian; Walsh, James E.; Lyng, Fiona M.

doi:10.3109/09553002.2010.518210

Cited by 13 publications

(17 citation statements)

References 38 publications

(53 reference statements)

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“…Contrasting with earlier studies with HEPES‐supplemented RPMI and normal DMEM‐F12 medium, which identified Rf photo‐conversion as the main causative factor for ROS/RNS formation, this present study data do not support such a strict mechanistic link 15, 25. According to EEM spectra (Fig.…”

Section: Discussioncontrasting

confidence: 99%

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Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality, cell physiology, and IgG production in CHO cultures

Neutsch

Kröll

Brunner

et al. 2018

J of Chemical Tech & Biotech

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BACKGROUNDMany vital components in bioprocess media are prone to photo‐conversion or photo‐degradation upon exposure to ambient light, with severe negative consequences for biomass yield and overall productivity. However, there is only limited awareness of light irradiation as a potential risk factor when working in transparent glass bioreactors, storage vessels or disposable bag systems. The chemical complexity of most media renders a root‐cause analysis difficult. This study investigated in a novel, holistic approach how light‐induced changes in media composition relate to alterations in radical burden, cell physiology, morphology, and product formation in industrial Chinese hamster ovary (CHO) bioprocesses.RESULTSTwo media formulations from proprietary and commercial sources were tested in a pre‐hoc light exposure scenario prior to cultivation. Using fluorescence excitation/emission (EEM) matrix spectroscopy, a photo‐sensitization of riboflavin was identified as a likely cause for drastically decreased IgG titers (up to −80%) and specific growth rates (−50% to −90%). Up to three‐fold higher radical levels were observed in photo‐degraded medium. On the biological side, this resulted in significant changes in cell morphology and aberrations in the normal IgG biosynthesis/secretion pathway.CONCLUSIONThese findings clearly illustrate the underrated impact of room light after only short periods of exposure, occurring accidentally or knowingly during bioprocess development and scale‐ up. The detrimental effects, which may share a common mechanistic cause at the molecular level, correlate well with changes in spectroscopic properties. This offers new perspectives for online monitoring concepts, and improved detectability of such effects in future. © 2018 The Authors. Journal of Chemical Technology & Biotechnology published by JohnWiley & Sons Ltd on behalf of Society of Chemical Industry.

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Section: Discussioncontrasting

confidence: 99%

“…A constant amount of radicals seems to be formed in situ without involvement of exogenous stress factors such as light, and to a different extent in different media formulations. Alternatively, it is possible that serum components (as were supplemented to DMEM) act as radical scavengers, which was reported for similar systems 16, 25…”

Section: Discussionmentioning

confidence: 78%

Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality, cell physiology, and IgG production in CHO cultures

Neutsch

Kröll

Brunner

et al. 2018

J of Chemical Tech & Biotech

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“…The presence of phenol red in the medium was found to significantly reduce the toxicity of riboflavin, however. Exposure in riboflavin-free medium resulted in significantly increased cell survival compared to identical exposure in riboflavin containing medium 21 . It is important therefore to expose in riboflavin free medium.…”

Section: Solar Exposurementioning

confidence: 89%

Raman spectroscopic mapping for the analysis of solar radiation induced skin damage

Ali¹,

Bonnier²,

Ptasiński³

et al. 2013

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“…5). Although both RB and riboflavin are phototoxic to cultured cells, 10,29,32 only riboflavin is phototoxic during photo-crosslinking, causing loss of keratocytes by apoptosis and necrosis to the same distance from the anterior surface as UVA penetration. 9,11 Formation of RB/collagen complexes may greatly reduce the amount of free RB available to enter cells, whereas riboflavin, which rapidly diffuses in cornea, 33 enters the keratocytes, where it absorbs UVA and initiates toxicity.…”

Section: Discussionmentioning

confidence: 99%

Collagen Cross-Linking Using Rose Bengal and Green Light to Increase Corneal Stiffness

Cherfan

Verter

Melki³

et al. 2013

Invest. Ophthalmol. Vis. Sci.

149

164

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PURPOSE. Photochemical cross-linking of corneal collagen is an evolving treatment for keratoconus and other ectatic disorders. We evaluated collagen cross-linking by rose bengal plus green light (RGX) in rabbit eyes and investigated factors important for clinical application.METHODS. Rose bengal (RB, 0.1%) was applied to deepithelialized corneas of enucleated rabbit eyes for 2 minutes. The diffusion distance of RB into the stroma was measured by fluorescence microscopy on frozen sections. RB-stained corneas were exposed to green (532-nm) light for 3.3 to 9.9 minutes (50-150 J/cm 2 ). Changes in the absorption spectrum during the irradiation were recorded. Corneal stiffness was measured by uniaxial tensiometry. The spatial distribution of the stromal elastic modulus was assessed by Brillouin microscopy. Viable keratocytes were counted on H&E-stained sections 24 hours posttreatment. RESULTS.RB penetrated approximately 100 lm into the corneal stroma and absorbed >90% of the incident green light. RGX (150 J/cm 2 ) increased stromal stiffness by 3.8-fold. The elastic modulus increased in the anterior approximately 120 lm of stroma. RB was partially photobleached during the 2-minute irradiation, but reapplication of RB blocked light transmission by >70%. Spectral measurements suggested that RGX initiated cross-linking by an oxygen-dependent mechanism. RGX did not decrease keratocyte viability.CONCLUSIONS. RGX significantly increases cornea stiffness in a rapid treatment (@12 minutes total time), does not cause toxicity to keratocytes and may be used to stiffen corneas thinner than 400 lm. Thus, RGX may provide an attractive approach to inhibit progression of keratoconus and other ectatic disorders.

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Medium-mediated effects increase cell killing in a human keratinocyte cell line exposed to solar-simulated radiation

Cited by 13 publications

References 38 publications

Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality, cell physiology, and IgG production in CHO cultures

Media photo‐degradation in pharmaceutical biotechnology – impact of ambient light on media quality, cell physiology, and IgG production in CHO cultures

Raman spectroscopic mapping for the analysis of solar radiation induced skin damage

Collagen Cross-Linking Using Rose Bengal and Green Light to Increase Corneal Stiffness

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