TABLE 1.
Studies on the association between UPE and skin disorders.
| Subjects | Measurement components | Body parts | Main results/conclusions | Year | Reference |
|---|---|---|---|---|---|
| Porcine skin samples in vitro | PMT | — | UPE generated by oxidation-stressed skin is mainly due to non-fluorescent photon emission via Trp amino acid; Measurement of UPE could be a highly sensitive method to assess oxidative processes in biological molecules | 2007 | Khabiri et al. (2008) |
| Porcine skin samples in vitro; Human skin in vivo | PMT | The inner forearms (in vivo) | UPE measurement following UVA excitation could precisely reflect a dose-dependent antioxidant effect of topically applied vitamin C and alpha-glucosyl rutin | 2007 | Hagens et al. (2008) |
| Human skin in vivo | PMT and CCD camera | The dorsal and the palm side of the hand | UPE increased after the application of H2O2; UPE measurement serves as a powerful non-invasive tool for monitoring peroxide-induced oxidative processes in the human skin | 2010 | Rastogi and Pospisil (2010) |
| Human skin in vivo | PMT | The dorsal surface of the hands | UV exposure resulted in an increase in UPE; The specific topical OPCs cream formulation reduced UV-induced UPE in the skin; The UPE measurement protocol can be utilized for the routine evaluation of the antioxidant efficacy of topical formulations on human skin | 2010 | Van Wijk et al. (2010) |
| Human skin in vivo | PMT and CCD camera | The dorsal side of the right hand | Spontaneous UPE can be used as a non-invasive tool for the temporal and spatial monitoring of the oxidative metabolic processes and intrinsic antioxidant system in human skin | 2011 | Rastogi and Pospisil (2011) |
| Human skin in vivo | PMT and CCD camera | The dorsal and palmar sides of the hand | Both UVA radiation and visible light exposure led to increased UPE; Two-dimensional photon imaging can serve as a potential tool for monitoring the oxidative stress in the human skin induced by various stress factors irrespective of its physical or chemical | 2012 | Prasad and Pospisil (2012) |
| Human skin in vivo | PMT | The inner upper arm and the outer forearm for women; the inner upper arm, outer forearm, and buttock for men | Steady-state UPE reflects not only intrinsic skin aging and cutaneous color but also the current oxidative status independent of skin aging | 2014 | Gabe et al. (2014) |
| Human skin tissue in vitro; Human skin in vivo | CCD camera | The backs of the Fingers (in vivo) | UPE measurement is a useful method to evaluate UV-induced oxidation in the human skin, and UPE imaging is an effective method to visually evaluate oxidative stress in the human skin | 2019 | Tsuchida et al. (2019b) |
| Human skin in vivo | CCD camera | The facial skin | Upe intensity was correlated with porphyrin score in the skin; UPE imaging of facial skin revealed regional variations of oxidative stress and site-specific increases in oxidative stress with age | 2020 | Tsuchida and Kobayashi (2020) |
| Human skin in vivo; Normal human epidermal keratinocytes in vitro | PMT | The inner upper arm | Long-lasting UPE generated between 1 and 3 min immediately after UV exposure, which is associated with lipid hydroperoxide production, is a valuable indicator to estimate and/or avoid severe cutaneous photodamage | 2020 | Gabe et al. (2021) |
Abbreviations: PMT, photon multiplier tube; CCD, charge-coupled devices; UPE, ultra-weak photon emission.