Factors influencing sunless tanning with dihydroxyacetone

Actinic keratosis metrics

Actinic keratosis (AK) is a common precancerous skin condition predominantly affecting older males with fair skin and significant UV exposure. The clinical significance of AK is related to its potential for malignant transformation and progression to squamous cell carcinoma (SCC). Accurate diagnosis of AK is essential for adequate treatment, evaluation of therapeutic efficacy, and mitigating the risk of developing SCC. However, clinician variability due to the subjective nature of current diagnostic tools presents significant challenges to achieving consistent and reliable AK diagnoses. Thus, there is no universally accepted standard for measuring AK.This review evaluates current methods for evaluating and diagnosing AK, focusing on clinician variability through inter- and intraobserver agreement. Eight peer-reviewed studies investigating the reliability of various approaches for AK evaluation show substantial variability in interobserver or intraobserver agreement, with most methods demonstrating only slight to moderate reliability. Some suggest that consensus discussions and simplified rating scales can modestly improve diagnostic reliability. However, remaining variability and the lack of a universally accepted standard for measuring AK underscore the need for more robust and standardized diagnostic and evaluation methods.The review emphasizes the need for improved diagnostic tools and standardized methods to enhance the accuracy and reliability of AK assessments. It also proposes applying a novel examination approach using 1,3-dihydroxyacetone (DHA) staining which may improve the visualization and identification of AK lesions. Advancements in these areas have significant potential, promising better clinical practices and patient outcomes in AK management.

Protection against visible light by dihydroxyacetone in erythropoietic protoporphyria

BACKGROUND

Patients with erythropoietic protoporphyria (EPP) are hypersensitive to long wave ultraviolet (UVA) radiation and visible light and they experience severe skin pain by light exposure. The patients have very limited treatment options. Sunless skin tanning with dihydroxyacetone (DHA) is now being investigated as a possible treatment modality of skin photosensitivity in EPP.

METHODS

We simulated the theoretical light protection factor provided by DHA application. In addition, we present 19 cases with EPP who were treated at our department with DHA weekly during spring and summer from 2018 to 2021 inclusive.

RESULTS

The protection factor against UVA and visible light was estimated to approximately two. Out of the 19 patients with EPP who were treated with DHA in 2018, 11 patients experienced a sustained good effect and continued to use the treatment on a weekly basis in the spring and summer of 2019, 2020, and 2021.

CONCLUSION AND PERSPECTIVES

Both the theoretical estimates and the uncontrolled study suggest that sunless tanning with DHA reduces photosensitivity in patients with EPP. Our hypothesis is that skin treated with DHA can tolerate twice the daylight dose compared to untreated skin before onset of skin symptoms. To validate this conclusion, we plan a randomized clinical trial to determine the effect of DHA application to reduce photosensitivity in patients with EPP under controlled clinical conditions. The study protocol for this trial is presented in the paper.

Comparison of Color Development Kinetics of Tanning Reactions of Dihydroxyacetone with Free and Protected Basic Amino Acids

Sunless tanning has become incredibly prevalent due to the increasing fashionable demand and the awareness of photodamage risks. The brown pigments are induced by dihydroxyacetone (DHA) and amino groups in the stratum corneum (SC) of skin via the Maillard reaction. While most studies concerning sunless tanning reactions have focused on free amino acids (AAs), little information is available on the impact of the side chain of AAs or proteins on this important reaction in cosmetic chemistry. To explore the reactivity and color development kinetics of different types of amino groups, three basic free AAs (Arg, His, and Lys) and three Nα-protected AAs (Boc-Arg-OH, Boc-His-OH, and Boc-Lys-OH) were used to react with DHA using a simplified model system at different reaction times, pH, and temperatures. Full factorial experiments were employed to design and analyze the effects of these three factors. The browning intensity and color characteristics were quantitatively evaluated. The factorial experiments showed that temperature had the most significant influence on the browning intensity and played a dominant role in the interactions with the reaction time and pH. It was found, for the first time, that Arg and His reacted with DHA more rapidly than Boc-Arg-OH and Boc-His-OH, while Boc-Lys-OH developed a stronger color than Lys under the same conditions, suggesting that ε-NH₂ of a lysine residue in peptides or proteins of SC may play a crucial role in the color development of DHA tanning. This study not only clearly illustrates the capability of the side chain of AAs to produce colored compounds but also provides a deeper understanding of DHA tanning.

Incorporation of Nanocatalysts for the Production of Bio-Oil from Staphylea holocarpa Wood

Biomass has been recognized as the most common source of renewable energy. In recent years, researchers have paved the way for a search for suitable biomass resources to replace traditional fossil fuel energy and provide high energy output. Although there are plenty of studies of biomass as good biomaterials, there is little detailed information about Staphylea holocarpa wood (S. holocarpa) as a potential bio-oil material. The purpose of this study is to explore the potential of S. holocarpa wood as a bio-oil. Nanocatalyst cobalt (II) oxide (Co₃O₄) and Nickel (II) oxide (NiO) were used to improve the production of bio-oil from S. holocarpa wood. The preparation of biofuels and the extraction of bioactive drugs were performed by the rapid gasification of nanocatalysts. The result indicated that the abundant chemical components detected in the S. holocarpa wood extract could be used in biomedicine, cosmetics, and biofuels, and have a broad industrial application prospect. In addition, nanocatalyst cobalt tetraoxide (Co₃O₄) could improve the catalytic cracking of S. holocarpa wood and generate more bioactive molecules at high temperature, which is conducive to the utilization and development of S. holocarpa wood as biomass. This is the first time that S. holocarpa wood was used in combination with nanocatalysts. In the future, nanocatalysts can be used to solve the problem of sustainable development of biological resources.

Successful treatment of aluminium phosphide poisoning by dihydroxyacetone: A two-case report study

WHAT IS KNOWN AND OBJECTIVE

Aluminium phosphide (AlP) is an agricultural fumigant which produces phosphine gas in the presence of moisture. Phosphine inhibits oxidative phosphorylation and causes cell death by inhibiting cytochrome C oxidase. Clinical manifestations of AlP poisoning are refractory hypotension, tachycardia, low oxygen saturation and severe metabolic acidosis.

CASE SUMMARY

Two cases received dihydroxyacetone (DHA) in addition to routine management of AlP poisoning. Administration of DHA (7 gr in 50 mL sodium bicarbonate, gavage) 2 times at a 1-hour interval improved the clinical signs.

WHAT IS NEW AND CONCLUSION

This is the first case report to highlight the safe and successful treatment of AlP poisoning with DHA. However, more clinical studies are recommended to determine the precise mechanism of DHA action.

Amino acids disrupt calcium-dependent adhesion of stratum corneum

In the stratum corneum, the intercellular junction made up of cadherin proteins provides the structural integrity of the framework. Ca2+ ions are known to play a key role in maintaining this junction. In this study, we hypothesized that Ca2+ chelation in stratum corneum will weaken the bond of the tissue and consequently promote exfoliation. Amino acids, ubiquitously existing as metabolites and building blocks of the body, have the molecular property to chelate Ca2+ ions. In the current study, we verified the Ca2+ chelating property of amino acids and demonstrated that amino acids can interfere with the interaction of cadherins, separate stratum corneum into pieces, and thereby stimulate the exfoliation process of skin. These results validate the importance of Ca2+ ion in the skin exfoliation process. Importantly, our findings indicate that amino acids may be efficiently used for improving skin conditions.

Study on the Use of Microbial Cellulose as a Biocarrier for 1,3-Dihydroxy-2-Propanone and Its Potential Application in Industry

Can microbial cellulose (MC) be used as a bio-carrier for 1,3-dihydroxy-2-propanone (DHA)? The aim of this study was to examine the possibility of using MC as a biomaterial for DHA transferring into the stratum corneum and inducing changes in skin color. The MC patches were obtained from Gluconacetobacter xylinus strain and incubated in solutions with various concentrations of DHA (g·L⁻¹: 20; 50; 80; 110) at 22 °C for 24 h. Afterwards; the patches were applied onto the skin for 15, 30, or 60 min. Skin color changes were assessed visually compared to a control patches without DHA. The intensity of skin color was increasing with the increase of DHA concentration and time of patches application. Application of MC patches with DHA (50 g·L⁻¹) for 30 min ensured the color which was considered the closest to the desired natural tan effect. MC patches containing DHA can be biocarriers enabling DHA transport into the stratum corneum and causing skin color changes. Study results indicate a new possibility for industrial applications of MC; e.g., as a biocarrier in masking the symptoms of vitiligo or production of self-tanning agents in the form of masks.

Dihydroxyacetone: An Updated Insight into an Important Bioproduct

Currently obtained from glycerol through microbial fermentation, the demand of 1,3-dihydroxyacetone (DHA) has significantly grown during the course of the last decade, driven by the consumer passion for a tan and increasing awareness of UV photodamage to the skin caused by prolonged exposure to the sun. We provide an updated bioeconomy perspective into a valued bioproduct (DHA), whose supply and production from glycerol, we argue in this study, will rapidly expand and diversify, with important global health benefits.

Detection of 1,3-dihydroxyacetone by tris(2,2'-bipyridine)ruthenium(II) electrochemiluminescence

1,3-Dihydroxyacetone, a common cosmetic material and food additive, has been successfully explored as an efficient electrochemiluminescence coreactant of Ru(bpy)₃²⁺ for the first time. It is about 25 times more effective than the well-known coreactant sodium oxalate. The high electrochemiluminescence efficiency allows sensitive detection of 1,3-dihydroxyacetone without any derivatization. The electrochemiluminescence method shows two linear electrochemiluminescence responses over the range of 5.0-500 μM and 500 μM-6.0 mM with a detection limit of 1.79 μM. The proposed method is at least two orders of magnitude more sensitive than other reported methods. Graphical abstract ECL intensity-potential profile of 1,3-dihydroxyacetone (DHA) and oxalate.

[Self-tanning and sunless tanning products]

Practically all currently available self-tanning products have as their active ingredient dihydroxyacetone (DHA), which may or may not be combined with erythrulose, tyrosine derivatives, and occasionally a naphthoquinone. The resulting skin tone, which resembles a natural tan, is due to chemical combination of the DHA with amino acids in the skin through the Maillard reaction. Polymer pigments known as melanoidins are formed and are fixed in the stratum corneum, where they remain until corneocyte desquamation occurs. The colouring thus achieved is semi-permanent and is well tolerated by skin. While the formulation of such products is complex and their storage difficult, no other substances provide more satisfactory or more lasting results.

Efficient production of dihydroxyacetone from biodiesel-derived crude glycerol by newly isolated Gluconobacter frateurii

The efficient production of dihydroxyacetone (DHA) on biodiesel-derived glycerol based media was developed. A newly isolated strain, Gluconobacter frateurii CGMCC 5397, could convert crude glycerol to DHA with high yield and productivity. In shake-flask fermentation, the DHA concentration of 73.1 gl(-1) was attained at 48 h using an optimum medium containing biodiesel-derived crude glycerol. When fed-batch fermentation was carried out in a 7-l stirred bioreactor with crude glycerol, the DHA concentration, productivity, and yield were 125.8 gl(-1), 2.6 gl(-1)h(-1), and 90.5% at 48 h, respectively. This study suggests that the inexpensive biodiesel-derived crude glycerol could be utilized for efficient production of DHA by G. frateurii.

Comparison of turbo-PUVA and conventional American-style PUVA in the treatment of psoriatic patients

BACKGROUND

Ultraviolet (UV)A protective properties of dihydroxyacetone (DHA) have been used as a topical UV-resisting barrier to optimize psoralens and UVA (turbo-PUVA). Starting doses and increments were based on the DHA diffuse reflectance spectroscopy-derived protection factor.

OBJECTIVE

To evaluate the efficacy of turbo-PUVA in psoriatic patients using a simpler method for determining starting doses and increments, in comparison to the conventional American-style PUVA photochemotherapy.

METHODS

Thirty psoriasis patients (15 on American-style PUVA and 15 on turbo-PUVA) were evaluated, each receiving PUVA twice weekly. Starting UVA dose was determined according to skin phototype for the American-style PUVA group and according to the patient's skin phototype x DHA SPF 3 in turbo-PUVA group. UVA increments used were 0.5-1.5 J/cm(2) per treatment in American-style PUVA and 25% of the previous dose in turbo-PUVA.

RESULTS

Turbo-PUVA group showed a significantly lower mean cumulative dose, a significantly higher psoriasis area and severity index score reduction, lesser mean number of treatment sessions, and less duration of treatment till remission (188.44+/-106.2 J/cm(2), 92.164+/-1.975%, 11.2+/-3.52 session, and 1.4+/-0.44 months, respectively) than conventional American-style PUVA group (255.13+/-18.304 J/cm(2), 74.725+/-10.976%, 30+/-0.00 sessions, and 3.75+/-0.00 months, respectively).

CONCLUSION

Turbo-PUVA is more effective and time convenient for the treatment of psoriasis with less cumulative dose than the conventional American-style PUVA.

Foundations and self-tanning products: Do they provide any protection from the sun?

As soon as the weather turns sunny, everyone wants a tan. People with skin phototypes III and IV, called melanocompetent, have no problem meeting this fashion requirement. But things are quite different for people with phototypes I and II and so these individuals look for alternative solutions. In essence, light skin burns easily when exposed to the sun. Therefore, light-skinned people are offered a cosmetic solution through self-tanning products or foundations. It seemed interesting to us to evaluate the sun protection power of this type of product. To do this, we used an in vitro method to determine the typical indicators related to sunscreen products, such as sun protection factor (SPF), ultraviolet (UV)-A protection factor (PF-UVA), UV-B/UV-A ratio as well as the critical wavelength because these artificial tanning products could be considered sunscreen products by users. It is important to know whether a self-tanning product and/or a foundation provide sun protection and whether they meet the standards set for other sunscreen products. Protection which is imbalanced for either UV-B or UV-A radiation is potentially harmful for users believing themselves adequately protected. To do this, we assembled the requisite conditions for forming melanoidins in the cosmetic itself. We tested seven amino acids found in the corneal cells of the epidermis. Regardless of the amino acid used, the corresponding SPF was essentially zero (approximately SPF 2). Foundations, on the other hand, proved to be much more interesting because they possess a non-negligible SPF as well as good photostability making these products safe in terms of their mode of application (applied once daily).

Contact dermatitis caused by sunless tanning treatment with dihydroxyacetone in hairless descendants of Mexican hairless dogs

Dihydroxyacetone (DHAT) is a color additive that is added to sunless tanning products to produce an artificial tan. Although this agent has been used extensively as safe sunless tanning, no published data are available to judge whether the abuse of DHAT causes a potential hazard to the human skin. The purpose of this study was to clarify whether frequent treatment with DHAT solutions had a deleterious effect on the wide skin surface of hairless descendants of Mexican hairless dogs. The skin reactions to the DHAT-treatment were investigated by daily clinical observations and histopathological examinations (21 and 42 days after the beginning of the DHAT-treatment). Clinical observations showed that skin color changes were apparent within 6 h after the first treatment with 5% DHAT solutions, with maximal darkening between 12 and 24 h. Twenty-one days after the beginning of the treatment with 5% DHAT solutions, the skin developed irritant dermatitis, and then the skin lesions gradually became severe during this study. Histopathological examinations showed entire epidermal thickening, 21 days after the beginning of the treatment with 5% DHAT solutions. Forty-two days after the beginning of the treatment with 5% DHAT solutions, the skin exhibited remarkable epidermal degeneration (hyperplastic and dyskeratotic changes) and moderate inflammatory reactions in the dermis. In severe dermatitic sites, I found focal epidermal necrosis or interepidermal blister formation beneath the thickened parakeatotic corneum. Throughout this study, there were no clinical and histopathological changes in the sites treated with vehicle alone. These results revealed that the skin coloring generated by frequent wide treatments with DHAT caused severe contact dermatitis which was associated with the damaged stratum corneum.

The Maillard Reaction for Sunlight Protection

During seven months of a clinical trial in spring, summer, and fall, 30 UVA/B/Soret band-photosensitive patients used sequential topical applications of dihydroxyacetone (DHA) followed by naphthoquinone only at bedtime and received excellent photoprotection without a single therapeutic failure or loss of any patient to follow-up. Eighteen of the 30 patients extended the limits of their photoprotection repeatedly over a seven-month period to tolerate without sunburns six to eight hours of midday sunlight under all kinds of occupational and recreational environmental conditions. Previously, the use of 3% DHA topically in earlier studies gave only a sun protection factor (SPF) of 3. In this reanalysis of the original notes of a previous clinical study of the melanoidins produced by DHA followed by naphthoquinone in the keratin layers of the epidermis of minimally pigmented Caucasian photosensitive patients, it is determined that these patients received a minimal UVB photoprotection of SPF 18 or more. This represents at least a sixfold amplification of the UVB photoprotective effect over the use of only dihydroxyacetone in the Maillard reaction.