Does lotion of any kind massively increase it?
FYI I ate two entire orange PEELS at the airport last night. https://www.instagram.com/inquilinekea/
Skin fluorescence, emitted by several AGEs, can be measured non-invasively with different devices. CLF (excitation at 370 nm, emission at 440 nm) contributes to the fluorescence signal. Apart from the AGE Reader which we will discuss in more detail below, another device, the SCOUT (VeraLight, Inc., Albuquerque, NM, USA), also measures skin fluorescence non-invasively, referred to as skin intrinsic fluorescence (SIF). The devices differ from each other by type light and spectrum [32]. The AGE Reader SU uses a black light source with a peak wavelength of 360–370 nm for illumination and measures emission in the 420–600 nm range. The SCOUT emits light with a light emitting diode with a wavelength centered at 375 nm and fluorescence is detected at 435–655 nm [33].
Different studies have shown that skin fluorescence correlates with mean HbA1c [34], [35]. This increases when HbA1c is measured over a longer period. When comparing SAF with a single measurement of HbA1c, the association with SAF is only moderate. This may depend on the short lifespan of red blood cells (8–12 weeks). Therefore, in comparison to the traditional measure HbA1c, SAF appears to be a good marker of past long-term tissue damage.
Globally, 34–47% of the variance of SAF can be statistically explained (Fig. 2) [36], [37]. Age is the most important contributor, 23.8–28.5%. Other, less important contributors include lifestyle factors, such as smoking and coffee intake, explaining 3.7–8.9% and 1.6–3.6%, respectively. Physical activity, age, gender, body mass index and packyears contributed to SAF by 25.5–35.8% in the final prediction model by van de Zande and colleagues [37]. Gender contributes less significantly, about 0.4–1.9%. Additionally, genetic factors play a role. In the LifeLines cohort by van Waateringe et al. genetic factors explained 2.1–2.7% of the variance in SAF [36]. However, the influence of heritability is probably much higher, but this has not been studied for SAF as far as we know. For example, 28% of the interindividual variation in lens protein autofluorescence was attributable to hereditary factors, in addition to environmental factors [38].
In addition, sun exposure is of importance. Sun exposure causes melanin levels to increase. This may cause absorption of fluorescent light leading to lower SAF values. Therefore, the SAF measurement is performed on the volar side of the forearm, because this location shows minimal seasonal change in pigment. Crisan et al. [27] found that AGE accumulation, e.g. CML, is higher in sun-exposed skin compared to sun-unexposed skin. However, in a previous study in white European subjects, intra-individual seasonal variance showed an Altman error of around 6%, suggesting that the effect of seasonal variance is probably limited [25]. Although a study by Meerwaldt et al. showed also that SAF measured at the volar site of the forearm and calf correlated strongly with each other (r = 0.98), the calf is not a practical location to assess SAF [25]. Fig. 4 shows a summary of the above mentioned components.
There are also skin fluorophores that may influence SAF, like keratin, NADH, and vitamin D [57], [64]. However, earlier research of our research group showed that variance in SAF could for a major part be explained by variations in the AGE pentosidine in dermal tissue of white European subjects [64].
Background/Purpose: Skin autofluorescence (AF) has been suggested as a non-invasive measure of oxidative stress in patients with diabetes and other diseases. We have previously shown that skin AF is also increased in patients with systemic sclerosis (SSc). As part of the disease process, patients with SSc undergo fundamental changes in their skin properties including skin thickening, alteration in perfusion secondary to microvascular dysfunction, and altered pigmentation. There are concerns that these might influence AF. The aim of this study was to determine whether skin AF is altered by these changes and thus to assess whether skin AF is a valid non-invasive technique to measure oxidative stress in SSc. This is a key question given the increasing evidence implicating oxidative stress in pathophysiology.
Strangely, coffee consumption increases it. I did drink A LOT of coffee just a few hours ago (though it’s probably unlikely that it would acutely increase it that much in a screening)
Results: The body lotion increased SAF by 18%. Day cream, sunscreen, and self-browning cream gave an increase of >100%. Except for body lotion, subsequent cleaning with alcohol swabs and washing with soap did not return SAF to baseline values. The effect of self-browning cream persisted for 2 weeks and that of sunscreen for 4 days. Hyperemia caused by a hot bath, capsicum cream, or postocclusive reactive hyperemia gave a decrease in SAF of, respectively, 18%, 22%, and 2.3%. Vasoconstriction caused by immersing the arm in cold water gave a 10% increase. Hydration state did not influence SAF.
Conclusions: Measurement of SAF is strongly affected by several skin creams. This effect was often not fully corrected by alcohol swabs and washing with soap and may persist for many days. Marked hyperemia and vasoconstriction also influence SAF. We advise avoiding these potential error sources.
However, there are several confounding factors that should be assessed prior to its broader application: these include presence of other fluorescent compounds in the skin that might be measured (eg, fluorophores),
Skin fluorophores
SAF assessment may not represent only the SAGEs content. The presence of endogenous fluorescent signals from skin fluoro- phores (eg, nicotinamide adenine dinucleotide) that are within the same excitation and emission ranges of the AGE Reader (350–410 and 420–600 nm. respectively) restricts the recogni- tion of specific fluorophores on the total fluorescence signal.13 However, 76% of the variance in the SAF signal correlates with specific SAGEs content6–8 and the broad excitation peak of this device is ideal to assess the development of chronic complica- tions in diabetes.37 Therefore, indicating that less costly spectro- meters or simple light sources can be implemented in this tool and so its application in the primary care can be extended.
Skin pigmentation
One important improvement for this instrument is to assess measurements in participants with darker skin pigmentation. The reliable analysis of SAGEs in darker skin subjects (SR<10%) has been particularly hindered, because strongly pig- mented skin tends to absorb excitation light and so the identifi- cation of increased SAF values cannot be predicted