Rearrangement and depletion of folate in human skin by ultraviolet radiation

Vitomics: A novel paradigm for examining the role of vitamins in human biology

The conventional view of vitamins reflects a diverse group of small molecules that facilitate critical aspects of metabolism and prevent potentially fatal deficiency syndromes. However, vitamins also contribute to the shaping and maintenance of the human phenome over lifecycle and evolutionary timescales, enabling a degree of phenotypic plasticity that operates to allow adaptive responses that are appropriate to key periods of sensitivity (i.e., epigenetic response during prenatal development within the lifecycle or as an evolved response to environmental challenge over a great many lifecycles). Individually, vitamins are important, but their effect is often based on nutrient-nutrient (vitamin-vitamin), nutrient-gene (vitamin-gene), and gene-gene interactions, and the environmental influence of shifting geophysical cycles, as well as evolving cultural practices. These ideas will be explored within what I refer to as the "adaptive vitome (vitomics)" paradigm.

The evolution of human skin pigmentation: A changing medley of vitamins, genetic variability, and UV radiation during human expansion

This review examines putative, yet likely critical evolutionary pressures contributing to human skin pigmentation and subsequently, depigmentation phenotypes. To achieve this, it provides a synthesis of ideas that frame contemporary thinking, without limiting the narrative to pigmentation genes alone. It examines how geography and hence the quality and quantity of UV exposure, pigmentation genes, diet-related genes, vitamins, anti-oxidant nutrients, and cultural practices intersect and interact to facilitate the evolution of human skin color. The article has a strong focus on the vitamin D-folate evolutionary model, with updates on the latest biophysical research findings to support this paradigm. This model is examined within a broad canvas that takes human expansion out of Africa and genetic architecture into account. A thorough discourse on the biology of melanization is provided (includes relationship to BH4 and DNA damage repair), with the relevance of this to the UV sensitivity of folate and UV photosynthesis of vitamin D explained in detail, including the relevance of these vitamins to reproductive success. It explores whether we might be able to predict vitamin-related gene polymorphisms that pivot metabolism to the prevailing UVR exposome within the vitamin D-folate evolutionary hypothesis context. This is discussed in terms of a primary adaptive phenotype (pigmentation/depigmentation), a secondary adaptive phenotype (flexible metabolic phenotype based on vitamin-related gene polymorphism profile), and a tertiary adaptive strategy (dietary anti-oxidants to support the secondary adaptive phenotype). Finally, alternative evolutionary models for pigmentation are discussed, as are challenges to future research in this area.

Biophysical evidence to support and extend the vitamin D-folate hypothesis as a paradigm for the evolution of human skin pigmentation

OBJECTIVE

To test the "vitamin D-folate hypothesis for the evolution of human skin pigmentation."

METHODS

Total ozone mapping spectrometer (TOMS) satellite data were used to examine surface UV-irradiance in a large (n = 649) Australian cross-sectional study population. Genetic analysis was used to score vitamin D- and folate-related gene polymorphisms (n = 22), along with two pigmentation gene variants (IRF4-rs12203592/HERC2-rs12913832). Red cell folate and vitamin D₃ were measured by immunoassay and HPLC, respectively.

RESULTS

Ultraviolet radiation (UVR) and pigmentation genes interact to modify blood vitamin levels; Light skin IRF4-TT genotype has greatest folate loss while light skin HERC2-GG genotype has greatest vitamin D₃ synthesis (reflected in both TOMS and seasonal data). UV-wavelength exhibits a dose-response relationship in folate loss within light skin IRF4-TT genotype (305 > 310 > 324 > 380 nm). Significant vitamin D₃ photosynthesis only occurs within light skin HERC2-GG genotype, and is maximal at 305 nm. Three dietary antioxidants (vitamins C, E, and β-carotene) interact with UVR and pigmentation genes preventing oxidative loss of labile reduced folate vitamers, with greatest benefit in light skin IRF4-TT subjects. The putative photosensitiser, riboflavin, did not sensitize red cell folate to UVR and actually afforded protection. Four genes (5xSNPs) influenced blood vitamin levels when stratified by pigmentation genotype; MTHFR-rs1801133/rs1801131, TS-rs34489327, CYP24A-rs17216707, and VDR-ApaI-rs7975232. Lightest IRF4-TT/darkest HERC2-AA genotype combination (greatest folate loss/lowest vitamin D₃ synthesis) has 0% occurrence. The opposing, commonest (39%) compound genotype (darkest IRF4-CC/lightest HERC2-GG) permits least folate loss and greatest synthesis of vitamin D₃ .

CONCLUSION

New biophysical evidence supports the vitamin D-folate hypothesis for evolution of skin pigmentation.

The evolution of human skin pigmentation involved the interactions of genetic, environmental, and cultural variables

The primary biological role of human skin pigmentation is as a mediator of penetration of ultraviolet radiation (UVR) into the deep layers of skin and the cutaneous circulation. Since the origin of Homo sapiens, dark, protective constitutive pigmentation and strong tanning abilities have been favored under conditions of high UVR and represent the baseline condition for modern humans. The evolution of partly depigmented skin and variable tanning abilities has occurred multiple times in prehistory, as populations have dispersed into environments with lower and more seasonal UVR regimes, with unique complements of genes and cultural practices. The evolution of extremes of dark pigmentation and depigmentation has been rare and occurred only under conditions of extremely high or low environmental UVR, promoted by positive selection on variant pigmentation genes followed by limited gene flow. Over time, the evolution of human skin pigmentation has been influenced by the nature and course of human dispersals and modifications of cultural practices, which have modified the nature and actions of skin pigmentation genes. Throughout most of prehistory and history, the evolution of human skin pigmentation has been a contingent and non-deterministic process.

A Cross-Sectional Study on the Combined Effect of Body Weight and Coffee Consumption on Serum Levels of Leptin, Vitamin B12, and Folic Acid in Healthy Young Adult Males

Purpose

Studies on the effect of body weight and coffee consumption on leptin, vitamin B12, and folic acid are scarce and conflicting. This study investigates the effect of body weight and/or coffee consumption rate on the serum levels of these molecules in healthy young adult males.

Patients and Methods

This observational cross-sectional study was carried out at the faculty of pharmacy, Applied Science Private University (ASU), Amman, Jordan, from July to September 2020. Young healthy males were invited to participate in the study and fill a questionnaire regarding lifestyle habits including coffee consumption during the last 3 months, medical history, and anthropometric measurements. Depending on BMI and extent of coffee consumption, participants were divided into 4 groups; normal body weight and moderate coffee consumption (NW/MCC) group; normal body weight and heavy coffee consumption (NW/HCC) group; overweight and moderate coffee consumption (OW/MCC) group; overweight and heavy coffee consumption (OW/HCC) group. Serum samples were taken to measure leptin, vitamin B12, and folic acid levels in addition to morning and midnight salivary cortisol and dehydroepiandrosterone (DHEA) samples.

Results

Healthy males (n = 122) aged 18 to 26 years continued participation in this study. Serum levels of leptin in NW/MCC, NW/HCC, OW/MCC, OW/HCC groups were 5.93, 5.75, 14.86, 16.79 ng/mL, respectively. Serum levels of vitamin B12 in these groups were 356.09, 402.71, 334.25, 331.05 pg/mL, respectively. While, the serum levels of folic acid were 8.92, 10.27, 10.12, 10.47 ng/mL, respectively. Body weight was positively associated with leptin (p = 0.00), negatively associated with vitamin B12 (p = 0.047), and not associated with folic acid (p = 0.235). Coffee consumption rate had no significant effect on leptin, vitamin B12, or folic acid. Finally, the combination of body weight and coffee consumption had no significant effect on leptin, vitamin B12, or folic acid.

Conclusion

There was no possible synergistic effect between body weight and coffee consumption rate on leptin, vitamin B12, or folic acid levels. However, overweight was associated with higher leptin, lower vitamin B12, and no change in folic acid levels.

Trial Registration

This trial was registered at clinicaltrials.gov as NCT04488731.

Will mesenchymal stem cells be future directions for treating radiation-induced skin injury?

Radiation-induced skin injury (RISI) is one of the common serious side effects of radiotherapy (RT) for patients with malignant tumors. Mesenchymal stem cells (MSCs) are applied to RISI repair in some clinical cases series except some traditional options. Though direct replacement of damaged cells may be achieved through differentiation capacity of MSCs, more recent data indicate that various cytokines and chemokines secreted by MSCs are involved in synergetic therapy of RISI by anti-inflammatory, immunomodulation, antioxidant, revascularization, and anti-apoptotic activity. In this paper, we not only discussed different sources of MSCs on the treatment of RISI both in preclinical studies and clinical trials, but also summarized the applications and mechanisms of MSCs in other related regenerative fields.

Vitamin-related phenotypic adaptation to exposomal factors: The folate-vitamin D-exposome triad

The biological role of two key vitamins, folic acid and vitamin D is so fundamental to life processes, it follows that their UV sensitivity, dietary abundance (both key exposomal factors) and variability in dependent genes will modify their functional efficacy, particularly in the context of maintaining the integrity and function of genome and epigenome. This article therefore examines folate and vitamin D-related phenotypic adaptation to environmental factors which vary across the human life cycle as well as over an evolutionary time-scale. Molecular mechanisms, key nutrigenomic factors, phenotypic maladaptation and evolutionary models are discussed.

Supplementation with 5-formyltetrahydrofolate alleviates ultraviolet B-inflicted oxidative damage in folate-deficient zebrafish

Ultraviolet (UV) is an omnipresent environmental carcinogen transmitted by sunlight. Excessive UV irradiation has been correlated to an increased risk of skin cancers. UVB, the most mutagenic component among the three UV constituents, causes damage mainly through inducing DNA damage and oxidative stress. Therefore, strategies or nutrients that strengthen an individual's resistance to UV-inflicted harmful effects shall be beneficial. Folate is a water-soluble B vitamin essential for nucleotides biosynthesis, and also a strong biological antioxidant, hence a micronutrient with potential of modulating individual's vulnerability to UV exposure. In this study, we investigated the impact of folate status on UV sensitivity and the protective activity of folate supplementation using a zebrafish model. Elevated reactive oxygen species (ROS) level and morphological injury were observed in the larvae exposed to UVB, which were readily rescued by supplementing with folic acid, 5-formyltetrahydrofolate (5-CHO-THF) and N-acetyl-L-cysteine (NAC). The UVB-inflicted abnormalities and mortality were worsened in Tg(hsp:EGFP-γGH) larvae displaying folate deficiency. Intriguingly, only supplementation with 5-CHO-THF, as opposed to folic acid, offered significant and consistent protection against UVB-inflicted oxidative damage in the folate-deficient larvae. We concluded that the intrinsic folate status correlates with the vulnerability to UVB-induced damage in zebrafish larvae. In addition, 5-CHO-THF surpassed both folic acid and NAC in preventing UVB-inflicted oxidative stress and injury in our current experimental zebrafish model.

Risk of basal cell carcinoma in a randomized clinical trial of aspirin and folic acid for the prevention of colorectal adenomas

BACKGROUND

Aspirin may reduce the risk of several types of cancer.

OBJECTIVES

To evaluate if folic acid is associated with risk of basal cell carcinoma (BCC).

METHODS

BCC incidence was evaluated in a randomized, double-blind, placebo-controlled clinical trial of aspirin (81 mg daily or 325 mg daily for ~3 years) and/or folic acid (1 mg daily for ~6 years) for the prevention of colorectal adenomas among 1121 participants with a previous adenoma. BCC was confirmed by blinded review of pathology reports.

RESULTS

One hundred and four of 958 non-Hispanic white participants were diagnosed with BCC over a median follow-up of 13·5 years. Cumulative incidence of BCC was 12% [95% confidence interval (CI) 7-17] for placebo, 16% (95% CI 11-21) for 81 mg aspirin daily and 15% (95% CI 10-20) for 325 mg aspirin daily [hazard ratio (HR) for any aspirin 1·45 (95% CI 0·93-2·26); HR for 81 mg daily 1·57 (95% CI 0·96-2·56); HR for 325 mg daily 1·33 (95% CI 0·80-2·20)]. BCC risk was higher with aspirin use in those without previous skin cancer but lower with aspirin use in those with previous skin cancer (P_interaction = 0·02 for 81 mg aspirin daily; P_interaction = 0·03 for 325 mg aspirin daily). Folic acid supplementation was unrelated to BCC incidence (HR 0·85; 95% CI 0·57-1·27).

CONCLUSIONS

Neither aspirin nor folic acid treatment had a statistically significant effect on risk of BCC. Subgroup analysis suggested that chemopreventive effects of nonsteroidal anti-inflammatory drugs may be specific to those at high risk for BCC.

The colours of humanity: the evolution of pigmentation in the human lineage

Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus Homo, and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling Homo and Homo sapiens, loss of melanin pigmentation occurred under natural selection as Homo sapiens dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of Homo sapiens dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour-associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic 'palette' for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.

Environmental effects of ozone depletion and its interactions with climate change: progress report, 2015

The Environmental Effects Assessment Panel (EEAP) is one of three Panels that regularly informs the Parties (countries) to the Montreal Protocol on the effects of ozone depletion and the consequences of climate change interactions with respect to human health, animals, plants, biogeochemistry, air quality, and materials. The Panels provide a detailed assessment report every four years. The most recent 2014 Quadrennial Assessment by the EEAP was published as a special issue of seven papers in 2015 (Photochem. Photobiol. Sci., 2015, 14, 1-184). The next Quadrennial Assessment will be published in 2018/2019. In the interim, the EEAP generally produces an annual update or progress report of the relevant scientific findings. The present progress report for 2015 assesses some of the highlights and new insights with regard to the interactive nature of the effects of UV radiation, atmospheric processes, and climate change.