Atrophic and hypertrophic photoaging: Clinical, histologic, and molecular features of 2 distinct phenotypes of photoaged skin

Melanocortin-1 receptor (MC1R): a review for dermatologists

Melanocortin-1 receptor (MC1R) and its variants have a pivotal role in melanin synthesis. However, MC1R has been associated to non-pigmentary pathways related to DNA-repair activities and inflammation. The aim of this review is to provide an up-to-date overview about the role of MC1R in the skin. Specifically, after summarizing the current knowledge about MC1R structure and polymorphisms, we report data concerning the correlation between MC1R, phenotypic traits, skin aging, other diseases and skin cancers and their risk assessment through genetic testing.

Comparison the Effect of Fractional RF Laser with Microneedling on Facial Skin Rejuvenation, Open Pores and Skin Lightening: A Non-Randomized Controlled Clinical Trial

Background

Effective skin rejuvenation treatments with RF technologies exist, with potential for personalized combination therapies based on individual factors. We compared microneedling and fractional RF laser effectiveness in rejuvenation, pore healing, and skin lightening.

Method

The research was a non-randomized clinical trial study conducted in 2021 at Ilam Skin Clinic, Ilam, western Iran on people applying for rejuvenation, skin lightening and improvement of open pores. People were voluntarily divided into two groups based on personal preferences (group A: microneedling, 25 people, group B: fractional RF, 25 people). After data collection, SPSS22 software was used for data analysis.

Results

The study revealed significant differences in the rates of low, moderate, and severe pain between the microneedling and fractional groups (10 vs. 16, 14 vs. 4, 1 vs. 5, respectively). Erythema showed no significant difference, with low, moderate, and severe cases reported in both groups. Swelling was lower in the microneedling group, but the difference was not significant. Bruising was similar in both groups, and staining was minimal. No herpes or infections were reported. The microneedling group showed better improvement in skin pores and skin lightening compared to the fractional group, with outcomes rated as good and excellent.

Conclusion

Microneedling surpassed the fractional group in skin rejuvenation, lightening, and improved pores. Considering RF lasers are approximately three times more expensive than microneedling, the research indicates that choosing microneedling is not only more cost-effective but also a superior rejuvenation technique.

The correlation between dermoscopy and clinical and pathological tests in the evaluation of skin photoaging

BACKGROUND

There are no standards for evaluating skin photoaging. Dermoscopy is a non-invasive detection method that might be useful for evaluating photoaging.

OBJECTIVE

To assess the correlation between the dermoscopic evaluation of photoaging and clinical and pathological evaluations.

METHODS

The age, clinical evaluation (Fitzpatrick classification, Glogau Photoaging Classification, and Chung's standardized image ruler), histopathology (Masson staining and MMP-1 immunohistochemistry), and dermoscopy (Hu's and Isik's) of 40 donor skin samples were analyzed statistically, and Spearman rank correlation analysis was performed.

RESULTS

There was a robust correlation between the total Hu scores and Isik dermoscopy. The correlation of dermoscopy with histopathology was higher than that of clinical evaluation methods. There is a strong correlation between telangiectases and lentigo. Xerosis, superficial wrinkle, diffuse erythema, telangiectases, and reticular pigmentation were significantly correlated with the three clinical evaluation methods. Superficial wrinkles were correlated with Masson, MMP-1, various clinical indicators, and other dermoscopic items.

CONCLUSION

There is a good correlation between dermoscopy and clinical and histopathological examination. Dermoscopy might help evaluate skin photoaging.

Variation of Ferroptosis-Related Markers in HaCaT Cell Photoaging Models Induced by UVB

Objective

To investigate the variation of ferroptosis-related markers in HaCaT cell photoaging models induced by ultraviolet-B (UVB).

Methods

UVB-treated HaCaT cells served as the model (UVB group) for cellular photoaging, whereas untreated HaCaT cells served as the control group. HaCaT cells were exposed to UVB and the ferroptosis inhibitor Ferrostatin-1 (Fer-1) as part of the UVB+Fer-1 group, and co-cultured with the ferroptosis inducer Erastin as part of the UVB+Erastin group. Reactive oxygen species (ROS) detection kit and senescence-related β galactosidase (SA-β-gal) staining were used to evaluate the senescence of HaCaT cells. Lipid reactive oxygen species were detected by C11 BODIPY581/591 probe and mitochondrial morphology was observed by transmission electron microscopy. The mRNA expressions of glutathione peroxidase 4 (GPX4) and ferroptosis-suppressor-protein 1 (FSP1) were detected by real-time reverse transcription-PCR (RT-RCP), and the level of GPX4 protein was measured by immunofluorescence assay.

Results

The UVB group had considerably greater levels of ROS, SA-β-gal, and lipid reactive oxygen species than the control group. The UVB group's mitochondrial volume was reduced, the membrane density increased, and the mitochondrial crest decreased or even disappeared. GPX4 and FSP1 expression levels were similarly found to be lower in the UVB group. Furthermore, the positive rate of SA-β-gal and lipid reactive oxygen species in the UVB+Fer-1 group was much lower than in the UVB group, but it was reverse in the UVB+Erastin group. This study showed that induced ferroptosis can aggravate aging, and vice versa.

Conclusion

According to the findings, ferroptosis may be linked to UVB-induced skin photoaging, which could be attenuated by inhibition of ferroptosis.

Skin ageing and topical rejuvenation strategies

Skin ageing is a complex process involving the additive effects of skin's interaction with its external environment, predominantly chronic sun exposure, upon a background of time-dependent intrinsic ageing. Skin health and beauty is considered one of the principal factors perceived to represent overall 'health and wellbeing'; thus, the demand for skin rejuvenation strategies has rapidly increased, with a worldwide annual expenditure expected to grow from $US24.6 billion to around $US44.5 billion by 2030 (https://www.databridgemarketresearch.com/reports/global-facial-rejuvenation-market). Skin rejuvenation can be achieved in several ways, ranging from laser and device-based treatments to chemical peels and injectables; however, topical skin care regimes are a mainstay treatment for ageing skin and all patients seeking skin rejuvenation can benefit from this relatively low-risk intervention. While the most efficacious topical rejuvenation treatment is application of tretinoin (all-trans retinoic acid) - a prescription-only medicine considered to be the clinical 'gold standard' - a hybrid category of 'cosmeceutical' products at the midpoint of the spectrum of cosmetics and pharmaceutical has emerged. This article reviews the clinical manifestations of skin ageing and the available topical treatments for skin rejuvenation, including retinoids, peptides and antioxidants.

Recent advances in exosomal non-coding RNA-based therapeutic approaches for photoaging

BACKGROUND

Photoaging is a degenerative biological process that affects the quality of life. It is caused by environmental factors including ultraviolet radiation (UVR), deep skin burns, smoking, active oxygen, chemical substances, and trauma. Among them, UVR plays a vital role in the aging process.

AIM

With the continuous development of modern medicine, clinical researchers have investigated novel approaches to treat aging. In particular, mesenchymal stem cells (MSCs), non-coding RNAs are involved in various physiological processes have broad clinical application as they have the advantages of convenient samples, abundant sources, and avoidable ethical issues.

METHODS

This article reviews research progress on five types of stem cell, exosomes, non-coding RNA in the context of photoaging treatment: adipose-derived stem cell, human umbilical cord MSCs, epidermal progenitor cells, keratinocyte stem cells, and hair follicle stem cells (HFSCs). It also includes stem cell related exosomes and their non-coding RNA research.

RESULTS

The results have clinical guiding significance for prevention and control of the onset and development of photoaging. It is found that stem cells secrete cytokines, cell growth factors, non-coding RNA, exosomes and proteins to repair aging skin tissues and achieve skin rejuvenation. In particular, stem cell exosomes and non-coding RNA are found to have significant research potential, as they possess the benefits of their source cells without the disadvantages which include immune rejection and granuloma formation.

Ultrasonographic analysis of facial skin thickness in relation to age, site, sex, and body mass index

BACKGROUND

Numerous nonsurgical but invasive cosmetic procedures are performed blindly in the dermis or subcutaneous fat layer of the facial skin.

OBJECTIVES

To measure the numerical skin thickness of the facial areas where dermatological procedures are performed by applying ultrasound techniques, and to make it possible to estimate the skin thickness by investigating the influence of several individual constitutional factors such as age, sex, and body mass index (BMI), so that these variables can be applied to estimate skin thickness.

MATERIALS AND METHODS

Skin thickness was measured at eight different facial points using an ultrasound machine (Affiniti 50; Philips Inc.). Demographic data were gathered using questionnaires. Manual BMI was calculated from the weight and height of each participant, and individual BMI measurements were performed using a body composition analyzer.

RESULTS

In terms of whole skin thickness, the thickest point was the mouth corner, and the thinnest point was the lateral forehead. The thickest point in the epidermis was the chin, and the thinnest point was the nasolabial fold. The thickest point in the dermis was the corner of the mouth, and the thinnest was the lateral forehead. Full skin thickness and dermal thickness were mostly lower in females. Skin thickness was not significantly correlated with BMI.

CONCLUSION

The skin thickness at different points on the face was variable, and realistic data about skin thickness can be obtained by in vivo ultrasonographic analysis of the skin.

Prospective study of efficacy and safety of non-ablative 1927 nm fractional thulium fiber laser in Asian skin photoaging

Background and Objective

Photoaging manifests as deeper wrinkles and larger pores. It has been tried to rejuvenate photoaging skin using a variety of lasers, including fractionated lasers, which are a popular photorejuvenation treatment. A new breakthrough for skin rejuvenation is the 1927 nm fractional thulium fiber laser (FTL), a laser and light-based treatment option. Clinical data regarding the FTL for treating photoaging are limited despite its effectiveness and safety. This study is aim to evaluate FTL' clinical effectiveness and safety.

Methods

Fitzpatrick skin types II-IV subjects with mild to moderate photoaging signs were enrolled in this prospective study. At intervals of one month, patients received three full face treatments. Wrinkles, spots, texture, pores, melanin index, erythema index (MI and EI), skin elasticity and hydration were measured with non-invasive tool. The epidermal thickness and dermal density on ultrasonography were compared between baseline and one month after all treatment sessions. The Global Score for Photoaging scale (GSP) was rated by two independent evaluators at the baseline and final follow-up visit. Secondary outcomes included patient-rated pain on a 10-point visual analog scale (VAS), as well as overall satisfaction. Following each treatment, adverse events were noted.

Results

Totally 27 subjects (24 females and 3 males) with Fitzpatrick skin types II to IV and a mean age of 44.41 (range33-64) were enrolled. Results suggests that the epidermal thickness has significantly improved after treatment. Statistically significant improvements in melanin index, skin elasticity and wrinkles were noted. An analysis of 12 subjects' reports (44%) suggested their skin felt brighter. No post-inflammatory hyperpigmentation changes or adverse events were observed. 70% patients reporting "satisfied" or "extremely satisfied".

Conclusions

In this study, FTL was found to be a safe and effective treatment option for treating photoaging.

New insights from non-invasive imaging: from prospection of skin photodamages to training with mobile application

The incidence of non‐melanoma skin cancer is on the rise and melanoma is among the most common cancers in the United States. Establishing an early diagnosis is essential for improving the prognosis of patients with skin cancer. High‐resolution non‐invasive imaging techniques may represent key tools for helping to identify and monitor early signs of skin cancer in seemingly healthy skin. Cumulative lifetime sun exposure leads to photoaging and photocarcinogenenis and the reaction of the skin to this solar‐induced damage is balanced between the DNA repair and photoprotection defence mechanisms of melanocytes and keratinocytes. In the first part of this article we provide an overview of these defence mechanisms and of the photoaging process, and discuss how non‐invasive imaging can be used to evaluate these changes. We then propose a model in which skin aging manifestations can be classified according to subject‐specific sun‐damage reaction profiles observed by reflectance confocal microscopy (RCM) and optical coherence tomography (OCT). These photoaging profiles include an atrophic phenotype characterized by actinic keratosis, and a hypertrophic phenotype characterized by hyperplastic pigmented skin. According to our model, these phenotypes may be predictive of predispositions to different types of skin cancer: squamous cell carcinoma for the atrophic phenotype and lentigo maligna and freckles for the hypertrophic phenotype. In addition to RCM and OCT, dermoscopy is another non‐invasive technique that has improved the diagnosis of skin cancer. In the second part of this article, we describe how the YouDermoscopy™ application can improve skills and thus enhance the dermoscopic recognition of sun‐induced skin tumours, and then show how this training tool enables its users to collaborate with dermatologists worldwide to obtain second opinions for the diagnosis of ambiguous lesions. Altogether, RCM, OCT and dermoscopy are valuable tools that can contribute significantly to improving the early diagnosis of precancerous and cancerous lesions.

Sunscreens and Photoaging: A Review of Current Literature

Sunscreens have been on the market for many decades as a means of protection against ultraviolet-induced erythema. Over the years, evidence has also shown their efficacy in the prevention of photoaging, dyspigmentation, DNA damage, and photocarcinogenesis. In the USA, most broad-spectrum sunscreens provide protection against ultraviolet B (UVB) radiation and short-wavelength ultraviolet A (UVA) radiation. Evidence suggests that visible light and infrared light may play a role in photoaging and should be considered when choosing a sunscreen. Currently, there is a paucity of US FDA-approved filters that provide protection against long UVA (> 370 nm) and none against visible light. Additionally, various sunscreen additives such as antioxidants and photolyases have also been reported to protect against and possibly reverse signs of photoaging. This literature review evaluates the utility of sunscreen in protecting against photoaging and further explores the requirements for an ideal sunscreen.

Clinical Translation of Scarless 0.33-mm Core Microbiopsy for Molecular Evaluation of Human Skin

BACKGROUND

Skin scarring can occur after punch biopsies, prohibiting their routine utilization, especially in the central face.

OBJECTIVES

This paper describes a scarless, 0.33-mm-diameter skin microbiopsy for molecular analysis of skin.

METHODS

This is was single-center, randomized, prospective study with 15 patients receiving no biopsy or biopsy on the left or right nasolabial fold. Six blinded raters assessed participant photos at baseline, 1 month, and 3 months post biopsy to evaluate for a visualized scar. Patient and Observer Scar Assessment Scale was completed. Additionally, biopsies from various skin regions of body along with arm skin after treatment with a single Erbium-YAG laser were processed for molecular analysis.

RESULTS

No patients exhibited scar formation based on evaluation of photographs and patient feedback. There was no mark at the biopsy site 7 days post-procedure. Optical coherence tomography showed a complete closing of the biopsy-punch wound 48 hours post-biopsy. One month post-biopsy, photography reviewers were unable to identify a scar, on average, 90% of the time at 3-month follow-up. Microbiopsies from various anatomical regions were successfully extracted for histology, electron microscopy, and gene expression analysis. Selected skin rejuvenation markers in the biopsies from Erbium-YAG-treated forearm skin resulted in significant gene upregulation in extracellular matrix molecules at 1 month posttreatment compared with untreated skin.

CONCLUSIONS

A core microbiopsy of 0.33 mm can be extracted reproducibly for histological, ultrastructural, and gene expression analysis without scarring. This allows repeated sampling for assessment of skin treatments and diseases, including aesthetics and wound-healing progress.

Advances in the Etiology, Detection, and Clinical Management of Seborrheic Keratoses

Seborrheic keratoses (SKs) are ubiquitous, generally benign skin tumors that exhibit high clinical variability. While age is a known risk factor, the precise roles of UV exposure and immune abnormalities are currently unclear. The underlying mechanisms of this benign disorder are paradoxically driven by oncogenic mutations and may have profound implications for our understanding of the malignant state. Advances in molecular pathogenesis suggest that inhibition of Akt and APP, as well as existing treatments for skin cancer, may have therapeutic potential in SK. Dermoscopic criteria have also become increasingly important to the accurate detection of SK, and other noninvasive diagnostic methods, such as reflectance confocal microscopy and optical coherence tomography, are rapidly developing. Given their ability to mimic malignant tumors, SK cases are often used to train artificial intelligence-based algorithms in the computerized detection of skin disease. These technologies are becoming increasingly accurate and have the potential to significantly augment clinical practice. Current treatment options for SK cause discomfort and can lead to adverse post-treatment effects, especially in skin of color. In light of the discontinuation of ESKATA in late 2019, promising alternatives, such as nitric-zinc and trichloroacetic acid topicals, should be further developed. There is also a need for larger, head-to-head trials of emerging laser therapies to ensure that future treatment standards address diverse patient needs.

Differences between perceived age and chronological age in women: A multi-ethnic and multi-centre study

Objective

Accuracy in assessing age from facial cues is important in social perception given reports of strong negative correlations between perceived age and assessments of health and attractiveness. In a multi‐ethnic and multi‐centre study, we previously documented similar patterns of female facial age assessments across ethnicities, influenced by gender and ethnicity of assessors.

Methods

Here we extend these findings by examining differences between estimated age from digital portraits and chronological age (Δ age) for 180 women from three age groups (20–34, 35–49, 50–66 years) and five ethnicities (36 images of each ethnicity, assessed for age on a continuous scale by 120 female and male raters of each ethnicity).

Results

Across ethnicities, Δ age was smallest in French assessors and largest in South African assessors. Numerically, French women were judged oldest and Chinese women youngest relative to chronological age. In younger women, Δ age was larger than in middle‐aged and older women. This effect was particularly evident when considering the interaction of women's age with assessor gender and ethnicity, independently and together, on Δ age.

Conclusion

Collectively, our findings suggest that accuracy in assessments of female age from digital portraits depends on the chronological age and ethnicity of the photographed women and the ethnicity and gender of the assessor. We discuss the findings concerning ethnic variation in skin pigmentation and visible signs of ageing and comment on implications for cosmetic science.

Reflectance Confocal Microscopy of Aging Skin and Skin Cancer

Skin aging is a complex process that causes morphologic variations. Some of these variations have been hypothesized to be involved in skin cancer development. This paper reviews current knowledge of the features of aged skin as seen with reflectance confocal microscopy (RCM). Basic principles of the technique are described, and the RCM features of healthy skin and skin cancer are briefly discussed. Moreover, the RCM features at different layers of young and elderly skin are described, as are the variations that occur with passing years and in relation to sun exposure that contribute to photoaging and the development of skin cancer. RCM enables the noninvasive evaluation, at quasi-histologic resolution, of aging-related skin changes, some of which are shared with skin cancer; this ability helps avoid skin biopsy. Further research is needed to understand the relation between skin aging and skin cancer development.

Detailed head localization and incidence of skin cancers

Skin cancers are the most common neoplasms; frequently, they localize on the face. The aim of paper is to present the incidence of skin tumors in a single center from 2017 to 2019, describe trends in its frequency and find relations between neoplasms and sex, type of cancer, and its size. An analysis of histopathological files from the surgical department between 2017 and 2019 was calculated. These items were selected: sex, age, type of skin cancer, subtype of basal cell carcinoma (BCC), grading of squamous cell carcinoma (SCC), localization and dimensions of the tumor. The study sample consisted of 387 cases. BCC was the most common cancer and its nodular type was the most frequent. In older patients, the vertical dimension of excised carcinoma was significantly larger. Moreover, this connection was detected only in women compared to men. There were statistically significant differences between dimensions of the skin cancer and sex. In men group, skin cancers had statistically higher vertical dimensions and larger surface areas. On the face and head, BCC more often localizes in the nasal area, while SCC on the auricle. It has been demonstrated that the older the patient, the larger the vertical dimension of the tumor. As such, tumor size is larger in men than in women, as women usually see their physicians sooner than men: cosmetic concerns are more important to them.

Effects of UV Induced-Photoaging on the Hair Follicle Cycle of C57BL6/J Mice

Purpose

To study the changes in the hair follicle cycle and related stem cells induced by photoaging to establish a mouse model of senescence in hair follicles.

Methods

There were 54 C57BL6/J mice randomly divided into three groups. The UVA group and the UVB group underwent photoaging induced by UV lamps for 8 weeks. Changes in skin and the hair follicle cycle were compared by physical signs, dermoscopy, and hematoxylin and eosin and Masson's staining in each group. Western blot, immunohistochemistry, and RT-qPCR were carried out to test canonical proteins and gene expression of the Wnt signaling pathway in the samples. Immunofluorescence was chosen to show variations in the stem cells related to the hair follicle cycle.

Results

There were more gray hairs in the UVA group than the other groups (P<0.05). Both diameter of the hair shaft and depth of hair root were significantly decreased in the UV groups (P<0.05). Stem cells and melanocytes of the hair follicles were reduced in the UVA group. UV, especially UVB, up-regulated the expression of the Wnt signaling pathway and prolonged anagen and telogen phases in the hair follicles, compared with the control group (P<0.05).

Conclusion

By decreasing the number of stem cells related to hair follicles, UVA induces hair follicle photoaging characterized by hair follicle miniaturization and gray hairs. UV up-regulated the expression of the Wnt signaling pathway, and the hair follicle cycle was significantly prolonged by UVB.

A genome-wide association study identifies novel gene associations with facial skin wrinkling and mole count in Latin Americans

BACKGROUND

Genome-wide association studies (GWASs) have identified genes influencing skin ageing and mole count in Europeans, but little is known about the relevance of these (or other genes) in non-Europeans.

OBJECTIVES

To conduct a GWAS for facial skin ageing and mole count in adults < 40 years old, of mixed European, Native American and African ancestry, recruited in Latin America.

METHODS

Skin ageing and mole count scores were obtained from facial photographs of over 6000 individuals. After quality control checks, three wrinkling traits and mole count were retained for genetic analyses. DNA samples were genotyped with Illumina's HumanOmniExpress chip. Association testing was performed on around 8 703 729 single-nucleotide polymorphisms (SNPs) across the autosomal genome.

RESULTS

Genome-wide significant association was observed at four genome regions: two were associated with wrinkling (in 1p13·3 and 21q21·2), one with mole count (in 1q32·3) and one with both wrinkling and mole count (in 5p13·2). Associated SNPs in 5p13·2 and in 1p13·3 are intronic within SLC45A2 and VAV3, respectively, while SNPs in 1q32·3 are near the SLC30A1 gene, and those in 21q21·2 occur in a gene desert. Analyses of SNPs in IRF4 and MC1R are consistent with a role of these genes in skin ageing.

CONCLUSIONS

We replicate the association of wrinkling with variants in SLC45A2, IRF4 and MC1R reported in Europeans. We identify VAV3 and SLC30A1 as two novel candidate genes impacting on wrinkling and mole count, respectively. We provide the first evidence that SLC45A2 influences mole count, in addition to variants in this gene affecting melanoma risk in Europeans.

Research progress on the potential delaying skin aging effect and mechanism of tea for oral and external use

Skin aging is characterized by the gradual loss of elasticity, the formation of wrinkles and various color spots, the degradation of extracellular matrix proteins, and the structural changes of the dermis. With the increasingly prominent problems of environmental pollution, social pressure, ozone layer thinning and food safety, skin problems have become more and more complex. The skin can reflect the overall health of the body. Skincare products for external use alone cannot fundamentally solve skin problems; it needs to improve the overall health of the body. Based on the literature review in recent 20 years, this paper systematically reviewed the potential delaying effect of tea and its active ingredients on skin aging by oral and external use. Tea is the second-largest health drink after water. It is rich in tea polyphenols, l-theanine, tea pigments, caffeine, tea saponins, tea polysaccharides and other secondary metabolites. Tea and its active substances have whitening, nourishing, anti-wrinkle, removing spots and other skincare effects. Its mechanism of action is ultraviolet absorption, antioxidant, anti-inflammatory, inhibition of extracellular matrix aging, inhibiting the accumulation of melanin and toxic oxidation products, balancing intestinal and skin microorganisms, and improving mood and sleep, among other effects. At present, tea elements skincare products are deeply loved by consumers. This paper provides a scientific theoretical basis for tea-assisted beauty and the high-end application of tea in skincare products.

The dark side of daylight: photoaging and the tumor microenvironment in melanoma progression

Continued thinning of the atmospheric ozone, which protects the earth from damaging ultraviolet radiation (UVR), will result in elevated levels of UVR reaching the earth's surface, leading to a drastic increase in the incidence of skin cancer. In addition to promoting carcinogenesis in skin cells, UVR is a potent extrinsic driver of age-related changes in the skin known as "photoaging." We are in the preliminary stages of understanding of the role of intrinsic aging in melanoma, and the tumor-permissive effects of photoaging on the skin microenvironment remain largely unexplored. In this Review, we provide an overview of the impact of UVR on the skin microenvironment, addressing changes that converge or diverge with those observed in intrinsic aging. Intrinsic and extrinsic aging promote phenotypic changes to skin cell populations that alter fundamental processes such as melanogenesis, extracellular matrix deposition, inflammation, and immune response. Given the relevance of these processes in cancer, we discuss how photoaging might render the skin microenvironment permissive to melanoma progression.

Distinctive clinical and histological characteristics of atrophic and hypertrophic facial photoageing

BACKGROUND

Photoageing describes complex cutaneous changes which occur following chronic exposure to solar ultraviolet radiation (UVR). Amongst White Northern Europeans, facial photoageing appears as distinct clinical phenotypes: 'hypertrophic' photoageing (HP) and 'atrophic' photoageing (AP). Deep, coarse wrinkles predominate in individuals with HP, whereas those with AP have relatively smooth, unwrinkled skin with pronounced telangiectasia. AP individuals have an increased propensity for developing keratinocyte cancers.

OBJECTIVES

To investigate whether histological differences underlie these distinct phenotypes of facial photoageing.

METHODS

Facial skin biopsies were obtained from participants with AP (10 M, 10 F; mean age: 78.7 years) or HP (10 M, 10 F; mean age: 74.5 years) and were assessed histologically and by immunohistochemistry.

RESULTS

Demographic characterization revealed 95% of AP subjects, as compared to 35% with HP, were Fitzpatrick skin type I/II; of these, 50% had a history of one or more keratinocyte cancers. There was no history of keratinocyte cancers in the HP cohort. Analysis of UVR-induced mitochondrial DNA damage confirmed that all volunteers had received similar lifetime cumulative doses of sun exposure. Histologically, male AP had a significantly thicker epidermis than did AP females or those of either sex with HP. HP facial skin exhibited severe solar elastosis, whereas in AP facial skin, solar elastosis was apparent only in females. Loss of papillary dermal fibrillin-rich microfibrils occurred in all HP and AP female subjects, but not in AP males. Furthermore, male AP had a significant reduction in collagen VII at the dermal-epidermal junction than did AP females or those of either sex with HP.

CONCLUSIONS

This study provides further evidence that AP and HP represent distinct clinical and histological entities. Knowledge of these two phenotypes is clinically relevant due to the increased prevalence of keratinocyte cancers in those - particularly males - with the AP phenotype.

Genetics of facial telangiectasia in the Rotterdam Study: a genome-wide association study and candidate gene approach

BACKGROUND

The severity of facial telangiectasia or red veins is associated with many lifestyle factors. However, the genetic predisposition remains unclear.

OBJECTIVES

We performed a genome-wide association study (GWAS) on facial telangiectasia in the Rotterdam Study (RS) and tested for replication in two independent cohorts. Additionally, a candidate gene approach with known pigmentation genes was performed.

METHODS

Facial telangiectasia were extracted from standardized facial photographs (collected from 2010-2013) of 2842 northwestern European participants (median age 66.9, 56.8% female) from the RS. Our GWAS top hits (P-value <10^-6 ) were tested for replication in 460 elderly women of the SALIA cohort and in 576 additional men and women of the RS. Associations of top single nucleotide polymorphisms (SNPs) with expression quantitative trait loci (eQTL) in various tissues were reviewed (GTEx database) alongside phenotype associations in the UK biobank database. SNP-based associations between known pigmentation genes and facial telangiectasia were tested. Conditional analysis on skin colour was additionally performed.

RESULTS

Our most significant GWAS signal was rs4417318 (P-value 5.38*10^-7 ), an intergenic SNP on chromosome 12 mapping to the SLC16A7 gene. Other suggestive SNPs tagged genes ZNF211, ZSCAN4, ICOS and KCNN3; SNP eQTLs and phenotype associations tagged links to the vascular system. However, the top signals did not pass significance in the two replication cohorts. The pigmentation genes KIAA0930, SLCA45A2 and MC1R, were significantly associated with telangiectasia in a candidate gene approach but not independently of skin colour.

CONCLUSION

In this GWAS on telangiectasia in a northwestern European population, no genome-wide significant SNPs were found, although suggestive signals indicate genes involved in the vascular system might be involved in telangiectasia. Significantly associated pigmentation genes underline the link between skin colour and telangiectasia.