Nicotinamide downregulates gene expression of interleukin-6, interleukin-10, monocyte chemoattractant protein-1, and tumour necrosis factor-α gene expression in HaCaT keratinocytes after ultraviolet B irradiation

Usage Frequency and Ecotoxicity of Skin Depigmenting Agents

Background/Objectives: Depigmenting cosmetic products are a fast-growing segment of the health products market, driven by consumer demand to address skin hyperpigmentation. Simultaneously, interest in products with a reduced environmental impact is increasing. However, the potential environmental risks, especially in aquatic ecosystems, of depigmenting products remain unexplored. This study assesses the usage frequency of skin depigmenting agents in cosmetic products and compiles data on the biodegradability and acute aquatic toxicity of the most prevalent compounds. Methods: A market analysis of Portuguese pharmacies and parapharmacies in 2022 identified prevalent depigmenting agents. Scientific evidence on their biodegradability and acute aquatic toxicity was compiled, and when data was unavailable, in silico predictions were conducted. Results: The study identified the ten most-used depigmenting agents in cosmetic products, including hydroxy/keto acids, as well as vitamin C and derivatives, with a usage frequency surpassing 50%. While most were naturally derived and showed low environmental risk, synthetic and highly lipophilic depigmenting agents found in 35 of 70 products (ascorbyl tetraisopalmitate/tetrahexyldecyl ascorbate and resorcinol derivatives) showed a higher potential for environmental hazard. Conclusions: The findings underscore the need for further research on the presence of these cosmetic ingredients in aquatic ecosystems and a reassessment of regulatory frameworks concerning their environmental impact. Mitigation strategies should emphasize biodegradable alternatives, renewable sources, and molecular modifications to reduce toxicity while maintaining depigmenting efficacy and skin safety. This study provides original insights into commonly used depigmenting agents in the health products market and their chemical structures, offering valuable opportunities for innovation in chemical/pharmaceutical industries.

Nicotinamide: A Multifaceted Molecule in Skin Health and Beyond

Nicotinamide (NAM), the amide form of vitamin B3, is a precursor to essential cofactors nicotinamide adenine dinucleotide (NAD⁺) and NADPH. NAD⁺ is integral to numerous cellular processes, including metabolism regulation, ATP production, mitochondrial respiration, reactive oxygen species (ROS) management, DNA repair, cellular senescence, and aging. NAM supplementation has demonstrated efficacy in restoring cellular energy, repairing DNA damage, and inhibiting inflammation by suppressing pro-inflammatory cytokines release. Due to its natural presence in a variety of foods and its excellent safety profile-even at high doses of up to 3 g/day-NAM is extensively used in the chemoprevention of non-melanoma skin cancers and the treatment of dermatological conditions such as blistering diseases, atopic dermatitis, rosacea, and acne vulgaris. Recently, its anti-aging properties have elevated NAM's prominence in skincare formulations. Beyond DNA repair and energy replenishment, NAM significantly impacts oxidative stress reduction, cell cycle regulation, and apoptosis modulation. Despite these multifaceted benefits, the comprehensive molecular mechanisms underlying NAM's actions remain not fully elucidated. This review consolidates recent research to shed light on these mechanisms, emphasizing the critical role of NAM in cellular health and its therapeutic potential. By enhancing our understanding, this work underscores the importance of continued exploration into NAM's applications, aiming to inform future clinical practices and skincare innovations.

Broccoli Byproduct Extracts Attenuate the Expression of UVB-Induced Proinflammatory Cytokines in HaCaT Keratinocytes

Broccoli byproducts are an important source of bioactive compounds, which provide important benefits for human skin due mainly to their antioxidant and anti-inflammatory properties. The primary target of UVB radiation is the basal layer of cells in the epidermis, with keratinocytes being the most abundant cell population in this layer. Given the wide range of side effects caused by exposure to UVB radiation, reducing the amount of UV light that penetrates the skin and strengthening the protective mechanisms of the skin are interesting strategies for the prevention of skin disorders. This work aims to evaluate the protective mechanisms triggered by broccoli by-products extract (BBE) on HaCaT keratinocytes exposed to UVB radiation as well as the study of the regenerative effect of these extracts on the barrier of skin keratinocytes damaged by superficial wounds as a strategy to revalorize this agricultural waste. The results obtained revealed that the BBEs exhibited a high cytoprotective effect on the HaCaT exposed to UVB light, allowing it to effectively reduce the intracellular content of ROS, as well as effectively attenuating the increase in proinflammatory cytokines (IL-1β, IL-6, IL-78, TNF-α) and COX-2 induced by this type of radiation. Furthermore, the BBE could be an excellent regenerative agent for skin wound repair, accelerating the migration capacity of keratinocytes thus contributing to the valorization of this byproduct as a valuable ingredient in cosmetic formulations.

Niacinamide: a review on dermal delivery strategies and clinical evidence

Niacinamide, an active form of vitamin B3, is recognised for its significant dermal benefits including skin brightening, anti-ageing properties and the protection of the skin barrier. Its widespread incorporation into cosmetic products, ranging from cleansers to serums, is attributed to its safety profile and proven efficacy. Recently, topical niacinamide has also been explored for other pharmaceutical applications, including skin cancers. Therefore, a fundamental understanding of the skin permeation behaviour of niacinamide becomes crucial for formulation design. Given the paucity of a comprehensive review on this aspect, we provide insights into the mechanisms of action of topically applied niacinamide and share the current strategies used to enhance its skin permeation. This review also consolidates clinical evidence of topical niacinamide for its cosmeceutical uses and as treatment for some skin disorders, including dermatitis, acne vulgaris and actinic keratosis. We also emphasise the current exploration and perspectives on the delivery designs of topical niacinamide, highlighting the potential development of formulations focused on enhancing skin permeation, particularly for clinical benefits.

Epidemiology and Risk Factors of Actinic Keratosis. What is New for The Management for Sun-Damaged Skin

Actinic keratosis (AK) is considered a chronic skin disease mostly caused by long-term exposure to UV radiation and other risk factors such as immunosuppression, leading to an individual susceptibility for skin cancer manifestation. The treatment of AK is laborious and costly, and the incidence of skin cancer is forecasted to double until the year 2030 in an aging society.Risk factors in AK for malignant transformation in cutaneous squamous cell carcinoma (cSCC) are not fully understood, but studies suggest that histological features, such as atypia in the basal epidermal third and basal proliferation (PRO score) in AK play a pivotal role for development of malignancy. As the clinical appearance of AK does not correlate with the risk for malignancy, guidelines suggest treating every single AK lesion upon diagnosis. Skin imaging techniques, such as line-field confocal optical coherence tomography (LC-OCT) can help to provide an individual holistic follow-up for AK lesions by non-invasive visualization of atypia and basal proliferation. A follow-up for patients with AK may be critical for treatment success in terms of strengthening therapy adherence. When AK presents therapy refractory, cSCC manifests in nearly 30% of the cases after several years. Patients with AK suffering from field cancerization and immunosuppression are susceptible for a severe course of disease including metastasis and high mortality rates. Those vulnerable subgroups benefit from close skin cancer screening, early adequate treatment and chemoprevention, such as niacinamide or acitretin. Skin cancer prevention is substantial. Primary prevention should include chemical and physical UV-light protection and avoidance of indoor tanning. Secondary prevention is essential in high-risk populations, such as fair skin type elderly men and STORs. Tertiary prevention should comprise adequate treatment strategies to prevent therapy resistance, reoccurrence and cSCC, especially when field cancerization and immunosuppression are present.

The altered metabolites contributed by dysbiosis of gut microbiota are associated with microbial translocation and immune activation during HIV infection

Background

The immune activation caused by microbial translocation has been considered to be a major driver of HIV infection progression. The dysbiosis of gut microbiota has been demonstrated in HIV infection, but the interplay between gut microbiota and its metabolites in the pathogenesis of HIV is seldom reported.

Methods

We conducted a case-controlled study including 41 AIDS patients, 39 pre-AIDS patients and 34 healthy controls. Both AIDS group and pre-AIDS group were divided according to clinical manifestations and CD4 + T cell count. We collected stool samples for 16S rDNA sequencing and untargeted metabolomics analysis, and examined immune activation and microbial translocation for blood samples.

Results

The pre-AIDS and AIDS groups had higher levels of microbial translocation and immune activation. There were significant differences in gut microbiota and metabolites at different stages of HIV infection. Higher abundances of pathogenic bacteria or opportunistic pathogen, as well as lower abundances of butyrate-producing bacteria and bacteria with anti-inflammatory potential were associated with HIV severity. The metabolism of tryptophan was disordered after HIV infection. Lower level of anti-inflammatory metabolites and phosphonoacetate, and higher level of phenylethylamine and polyamines were observed in HIV infection. And microbial metabolic pathways related to altered metabolites differed. Moreover, disrupted metabolites contributed by altered microbiota were found to be correlated to microbial translocation and immune activation.

Conclusions

Metabolites caused by dysbiosis of gut microbiota and related metabolic function are correlated to immune activation and microbial translocation, suggesting that the effect of microbiota on metabolites is related to intestinal barrier disruption in HIV infection.

Efficiency of nicotinamide-based supportive therapy in lymphopenia for patients with ordinary or severe COVID-19: A randomized controlled trial

BACKGROUND

This study aimed to investigate the efficiency of nicotinamide-based supportive therapy for lymphopenia in patients with coronavirus disease-2019 (COVID-19).

METHODS

Twenty four patients diagnosed with COVID-19 were randomly divided into 2 groups (n = 12) during hospitalization in a ratio of 1:1. Based on conventional treatment, the treatment group was administered 100 mg nicotinamide 5 times a day for 2 days. The control group received routine treatment only. The primary endpoint was the change in the absolute lymphocyte count. The secondary endpoints included both in-hospital death and the composite endpoint of aggravation, according to upgraded oxygen therapy, improved nursing level, and ward rounds of superior physicians for changes in conditions.

RESULTS

Full blood counts before and after nicotinamide administration were comparable in each group (all P > .05). Before and after receiving nicotinamide, mean absolute lymphocyte counts were similar between the two groups ([0.94 ± 0.26] × 109/L vs [0.89 ± 0.19] × 109/L, P = .565; [1.15 ± 0.48] × 109/L vs [1.02 ± 0.28] × 109/L, P = .445, respectively). Therefore, there was no statistically significant difference in the lymphocyte improvement rate between the two groups (23.08 ± 46.10 vs 16.52 ± 24.10, P = .67). There was also no statistically significant difference in the secondary endpoints between the two groups.

CONCLUSION

Among patients with COVID-19, there was no statistically significant difference in the change of whole blood counts and absolute lymphocyte counts before and after intervention in both groups. Therefore, no new evidence has been found regarding the effect of niacinamide on lymphopenia in COVID-19 patients.

Nutrition and nonmelanoma skin cancers

Nonmelanoma skin cancer (NMSC), the most widely diagnosed cancer in the United States, is rising in incidence despite public health and educational campaigns that highlight the importance of sun avoidance. It is,therefore, important to establish other modifiable risk factors that may be contributing to this increase. There is a growing body of evidence in the literature suggesting certain nutrients may have protective or harmful effects on NMSC. We review the current literature on nutrition and its effect on NMSC with a focus on dietary fat, vitamin A, nicotinamide, folate, vitamin C, vitamin D, vitamin E, polyphenols, and selenium.

Nicotinamide Attenuates UV-Induced Stress Damage in Human Primary Keratinocytes from Cancerization Fields

UVB radiation directly damages DNA, increases ROS and nitric oxide (NO) release, and promotes inflammation leading to genomic instability and cell death. Nicotinamide (NAM) is the precursor of NAM adenine dinucleotide, essential for cell energy production and DNA damage repair. NAM protects HaCat cells from UV-induced impairment; however, little is known about its effects on human primary keratinocytes and those isolated from field cancerization (i.e., field cancerization human primary keratinocytes [FC-HPKs]). We examined the role of NAM against UV-induced oxidative stress damages in FC-HPKs, isolated from precancerous lesions and skin cancers, and in normal human epidermal keratinocytes. Cells were treated for 18, 24, and 48 hours with NAM (5, 25, and 50 μM, respectively) before UVB irradiation. FC-HPK showed four-fold higher basal ROS levels than normal human epidermal keratinocytes; NAM downregulated ROS production only in irradiated FC-HPKs, which showed a greater sensibility to UV rays. UV exposure increased OGG1, inducible nitric oxide synthase, and IL-1β expression, an effect counteracted by NAM pretreatment. Intracellular nitric oxide production and DNA damages were inhibited by NAM exposure before irradiation. Collectively, our findings indicate that pretreatment with 25 μM NAM 24 hours before UVB irradiation effectively prevents oxidative stress formation, DNA damage, and inflammation in both normal human epidermal keratinocytes and FC-HPKs.

Mechanistic Basis and Clinical Evidence for the Applications of Nicotinamide (Niacinamide) to Control Skin Aging and Pigmentation

Vitamin B3 (nicotinic acid, niacin) deficiency causes the systemic disease pellagra, which leads to dermatitis, diarrhea, dementia, and possibly death depending on its severity and duration. Vitamin B3 is used in the synthesis of the NAD+ family of coenzymes, contributing to cellular energy metabolism and defense systems. Although nicotinamide (niacinamide) is primarily used as a nutritional supplement for vitamin B3, its pharmaceutical and cosmeceutical uses have been extensively explored. In this review, we discuss the biological activities and cosmeceutical properties of nicotinamide in consideration of its metabolic pathways. Supplementation of nicotinamide restores cellular NAD+ pool and mitochondrial energetics, attenuates oxidative stress and inflammatory response, enhances extracellular matrix and skin barrier, and inhibits the pigmentation process in the skin. Topical treatment of nicotinamide, alone or in combination with other active ingredients, reduces the progression of skin aging and hyperpigmentation in clinical trials. Topically applied nicotinamide is well tolerated by the skin. Currently, there is no convincing evidence that nicotinamide has specific molecular targets for controlling skin aging and pigmentation. This substance is presumed to contribute to maintaining skin homeostasis by regulating the redox status of cells along with various metabolites produced from it. Thus, it is suggested that nicotinamide will be useful as a cosmeceutical ingredient to attenuate skin aging and hyperpigmentation, especially in the elderly or patients with reduced NAD+ pool in the skin due to internal or external stressors.

Keratinocyte Carcinoma and Photoprevention: The Protective Actions of Repurposed Pharmaceuticals, Phytochemicals and Vitamins

Simple Summary

Keratinocyte carcinoma is the most common type of cancer. Sun exposure and ultraviolet radiation are significant contributors to the development of carcinogenesis, mediated by DNA damage, increased oxidative stress, inflammation, immunosuppression and dysregulated signal transduction. Photoprevention involves using different compounds to delay or prevent ultraviolet radiation-induced skin cancer. In this review, we look at new avenues for systemic photoprevention that are based on pharmaceuticals, plant-derived phytochemicals and vitamins. We also investigate the mechanisms underlying these strategies for preventing the onset of carcinogenesis.

Abstract

Ultraviolet radiation (UVR) arising from sun exposure represents a major risk factor in the development of keratinocyte carcinomas (KCs). UVR exposure induces dysregulated signal transduction, oxidative stress, inflammation, immunosuppression and DNA damage, all of which promote the induction and development of photocarcinogenesis. Because the incidence of KCs is increasing, better prevention strategies are necessary. In the concept of photoprevention, protective compounds are administered either topically or systemically to prevent the effects of UVR and the development of skin cancer. In this review, we provide descriptions of the pathways underlying photocarcinogenesis and an overview of selected photoprotective compounds, such as repurposed pharmaceuticals, plant-derived phytochemicals and vitamins. We discuss the protective potential of these compounds and their effects in pre-clinical and human trials, summarising the mechanisms of action involved in preventing photocarcinogenesis.

Oral nicotinamide: The role in skin cancer chemoprevention

The incidence of skin cancer has gradually increased in the last years and exposition to ultraviolet radiation remains the main risk factor. We performed a comprehensive review on the role of nicotinamide (NAM) in the chemoprevention of skin cancers. NAM, a water-soluble form of vitamin B3, interferes with skin carcinogenesis as it regulates immunosuppressor genes such as p53 and sirtuins and restores intracellular level of NAD+, a co-enzyme essential for energy production. Efficacy and safety of NAM was evaluated in a Phase III double-blinded control-placebo study (ONTRAC), thus demonstrating that the incidence of actinic keratoses and non-melanoma skin cancers was lower in the nicotinamide group than in placebo group. Further studies showed the efficacy of NAM also in transplanted patients and among inhabitants living in arsenic contamination areas. Despite the quick response to NAM supplementation, its intake need to be carried on chronically as the efficacy seems to vanish rapidly.

Safety and efficacy of a novel home-use device for light-potentiated (LED) skin treatment

Skin structure and function results from a dynamic interplay between dermal and epidermal cell types. Optimizing skin health through an effective and long-lasting skin care regime therefore requires a global approach, encompassing various mechanisms to stimulate this interplay beyond the action scope of a classical topical solution. This study evaluates the impact of a novel home-use device combining a topical serum, light-emitting diodes and massage on the clinical signs of extrinsic skin aging. The innovative principle relies on potentiating the effect of active ingredients contained in the topical serum with visible and near infra-red photons to prevent extracellular matrix degradation and promote its reconstruction. After in vitro and ex vivo investigations, a clinical study assessed the safety and efficacy of a daily treatment with the home-use device for 28 days. A significant increases in skin density and radiance while reducing the wrinkles was obtained with no side effects.

Nicotinamide for photoprotection and skin cancer chemoprevention: A review of efficacy and safety

Nicotinamide is a water-soluble vitamin B3 derivative that has many roles in medicine. This review examines the role of nicotinamide in dermatology and its actions in preventing photoageing and skin cancers in humans. Nicotinamide prevents ultraviolet radiation (UV) from reducing ATP levels and inhibiting glycolysis, thus preventing the UV radiation-induced energy crisis. This enhances DNA repair and reduces UV-induced suppression of immunity. Randomised controlled clinical trials have also shown that nicotinamide reduces transepidermal water loss and the development of new non-melanoma skin cancers in high-risk humans. This review also examines nicotinamide's safety profile.

Clinical and in vitro evaluation of new anti-redness cosmetic products in subjects with winter xerosis and sensitive skin

Objective

To demonstrate the in vitro activities of panthenol, palmitoylethanolamide (PEA), and niacinamide (NAM) and determine the biophysical properties, clinical safety, tolerability together with efficacy of two developmental anti‐redness (AR) formulations containing these ingredients, in alleviating facial redness associated with winter xerosis in healthy volunteers with sensitive skin.

Methods

The anti‐inflammatory and skin protective properties of panthenol, PEA and NAM were evaluated in vitro. The physical properties of the AR formulations were analysed using measurement of water vapour transport rate (WVTR) and infrared spectroscopy. Clinical studies were performed between the months of December and April (2014–2015) with efficacy assessed during the winter. Facial redness, irritation, sensitization potential, photo‐irritation, and photo‐sensitization were evaluated. Self‐assessed adverse reactions were reported in diaries of use.

Results

Panthenol and PEA reduced prostaglandin E₂, interleukin‐6, and thymic stromal lymphopoietin levels in vitro, while NAM induced nicotinamide adenine dinucleotide (NAD) levels and the keratinocyte differentiation markers: filaggrin (2‐fold increase, P < 0.001), loricrin (2‐fold increase, P < 0.05), involucrin (2 fold increase, P < 0.001) & peroxisomal proliferator activated receptor‐alpha (1.5 fold increase, P < 0.05). The two AR products exhibited low WVTR vs. no treatment (P < 0.001) and displayed an ordered lipid structure. The day cream formulation protected against ultraviolet B radiation in vitro. A total of 382 participants were included in clinical studies which showed the AR formulations significantly improved facial redness associated with winter xerosis (Day 29 mean change from baseline: AR day cream 0.77 (P < 0.001); AR serum 0.67 (P < 0.001)). No irritation, sensitization, photo‐irritation, photo‐sensitization or product‐related adverse reactions were observed or reported in the clinical studies.

Conclusion

The new products significantly improved skin redness associated with winter xerosis in participants with self‐perceived sensitive skin. Both products were well tolerated with a suitable safety profile for topical use in subjects with sensitive skin.

Possible Adverse Effects of High-Dose Nicotinamide: Mechanisms and Safety Assessment

Nicotinamide (NAM) at doses far above those recommended for vitamins is suggested to be effective against a wide spectrum of diseases and conditions, including neurological dysfunctions, depression and other psychological disorders, and inflammatory diseases. Recent increases in public awareness on possible pro-longevity effects of nicotinamide adenine dinucleotide (NAD+) precursors have caused further growth of NAM consumption not only for clinical treatments, but also as a dietary supplement, raising concerns on the safety of its long-term use. However, possible adverse effects and their mechanisms are poorly understood. High-level NAM administration can exert negative effects through multiple routes. For example, NAM by itself inhibits poly(ADP-ribose) polymerases (PARPs), which protect genome integrity. Elevation of the NAD+ pool alters cellular energy metabolism. Meanwhile, high-level NAM alters cellular methyl metabolism and affects methylation of DNA and proteins, leading to changes in cellular transcriptome and proteome. Also, methyl metabolites of NAM, namely methylnicotinamide, are predicted to play roles in certain diseases and conditions. In this review, a collective literature search was performed to provide a comprehensive list of possible adverse effects of NAM and to provide understanding of their underlying mechanisms and assessment of the raised safety concerns. Our review assures safety in current usage level of NAM, but also finds potential risks for epigenetic alterations associated with chronic use of NAM at high doses. It also suggests directions of the future studies to ensure safer application of NAM.

The Role of Nicotinamide in Cancer Chemoprevention and Therapy

Nicotinamide (NAM) is a water-soluble form of Vitamin B3 (niacin) and a precursor of nicotinamide-adenine dinucleotide (NAD⁺) which regulates cellular energy metabolism. Except for its role in the production of adenosine triphosphate (ATP), NAD⁺ acts as a substrate for several enzymes including sirtuin 1 (SIRT1) and poly ADP-ribose polymerase 1 (PARP1). Notably, NAM is an inhibitor of both SIRT1 and PARP1. Accumulating evidence suggests that NAM plays a role in cancer prevention and therapy. Phase III clinical trials have confirmed its clinical efficacy for non-melanoma skin cancer chemoprevention or as an adjunct to radiotherapy against head and neck, laryngeal, and urinary bladder cancers. Evidence for other cancers has mostly been collected through preclinical research and, in its majority, is not yet evidence-based. NAM has potential as a safe, well-tolerated, and cost-effective agent to be used in cancer chemoprevention and therapy. However, more preclinical studies and clinical trials are needed to fully unravel its value.

NAD+ therapy in age-related degenerative disorders: A benefit/risk analysis

Nicotinamide adenine dinucleotide (NAD+) is an essential pyridine nucleotide that is present in all living cells. NAD+ acts as an important cofactor and substrate for a multitude of biological processes including energy production, DNA repair, gene expression, calcium-dependent secondary messenger signalling and immunoregulatory roles. The de novo synthesis of NAD+ is primarily dependent on the kynurenine pathway (KP), although NAD+ can also be recycled from nicotinic acid (NA), nicotinamide (NAM) and nicotinamide riboside (NR). NAD+ levels have been reported to decline during ageing and age-related diseases. Recent studies have shown that raising intracellular NAD+ levels represents a promising therapeutic strategy for age-associated degenerative diseases in general and to extend lifespan in small animal models. A systematic review of the literature available on Medline, Embase and Pubmed was undertaken to evaluate the potential health and/or longevity benefits due to increasing NAD+ levels. A total of 1545 articles were identified and 147 articles (113 preclinical and 34 clinical) met criteria for inclusion. Most studies indicated that the NAD+ precursors NAM, NR, nicotinamide mononucleotide (NMN), and to a lesser extent NAD+ and NADH had a favourable outcome on several age-related disorders associated with the accumulation of chronic oxidative stress, inflammation and impaired mitochondrial function. While these compounds presented with a limited acute toxicity profile, evidence is still quite limited and long-term human clinical trials are still nascent in the current literature. Potential risks in raising NAD+ levels in various clinical disorders using NAD+ precursors include the accumulation of putative toxic metabolites, tumorigenesis and promotion of cellular senescence. Therefore, NAD+ metabolism represents a promising target and further studies are needed to recapitulate the preclinical benefits in human clinical trials.

Diverse therapeutic efficacies and more diverse mechanisms of nicotinamide

BACKGROUND

Nicotinamide (NAM) is a form of vitamin B3 that, when administered at near-gram doses, has been shown or suggested to be therapeutically effective against many diseases and conditions. The target conditions are incredibly diverse ranging from skin disorders such as bullous pemphigoid to schizophrenia and depression and even AIDS. Similar diversity is expected for the underlying mechanisms. In a large portion of the conditions, NAM conversion to nicotinamide adenine dinucleotide (NAD⁺) may be a major factor in its efficacy. The augmentation of cellular NAD⁺ level not only modulates mitochondrial production of ATP and superoxide, but also activates many enzymes. Activated sirtuin proteins, a family of NAD⁺-dependent deacetylases, play important roles in many of NAM's effects such as an increase in mitochondrial quality and cell viability countering neuronal damages and metabolic diseases. Meanwhile, certain observed effects are mediated by NAM itself. However, our understanding on the mechanisms of NAM's effects is limited to those involving certain key proteins and may even be inaccurate in some proposed cases.

AIM OF REVIEW

This review details the conditions that NAM has been shown to or is expected to effectively treat in humans and animals and evaluates the proposed underlying molecular mechanisms, with the intention of promoting wider, safe therapeutic application of NAM.

KEY SCIENTIFIC CONCEPTS OF REVIEW

NAM, by itself or through altering metabolic balance of NAD⁺ and tryptophan, modulates mitochondrial function and activities of many molecules and thereby positively affects cell viability and metabolic functions. And, NAM administration appears to be quite safe with limited possibility of side effects which are related to NAM's metabolites.

miR-9 regulates melanocytes adhesion and migration during vitiligo repigmentation induced by UVB treatment

The decreased adhesion ability of melanocytes to the neighboring keratinocytes prompts melanocytes to lose from the epidermis, comprising the critical step in vitiligo pathogenesis. The repigmentation process involves the migration of melanocytes to the lesional area. This study aims to investigate the role and mechanism of microRNA (miR)-9 in the adhesion and migration of melanocytes during vitiligo repigmentation induced by UVB treatment. The HaCaT keratinocytes were used to mimic lesional condition and the PIG1 melanocytes as perilesional condition. Human lesional vitiligo specimens showed increased miR-9 and decreased adhesion molecules such as E-cadherin and β1 integrin. Furthermore, UVB exposure upregulated IL-10, E-cadherin, and β1 integrin, downregulated miR-9 in HaCaT cells. Moreover, the increased IL-10 by UVB exposure decreased miR-9 level by inducing miR-9 methylation via methyltransferase DNMT3A in HaCaT cells. Additionally, miR-9 targeted and inhibited E-cadherin and β1 integrin in HaCaT cells, and suppressed migration of PIG1 cells to UVB-exposed HaCaT cells. In conclusion, miR-9 was suppressed by IL-10 and inhibited migration of PIG1 cells to HaCaT cells during UVB-mediated vitiligo repigmentation.

Association of NFKB1 -94ATTG ins/del polymorphism (rs28362491) with pemphigus vulgaris

Pemphigus vulgaris is a rare chronic blistering skin disease resulting from IgG autoantibodies directed against transmembrane desmosomal glycoprotein desmoglein 3 and is the most common form of pemphigus. Since interleukin-1 receptor-associated kinase (IRAK-1)/nuclear factor-kappa B (NF-kappa B) pathway plays an essential role in the pathogenesis of autoimmune diseases, the aim of the present study was to explore the role of polymorphisms in three genes, named IRAK1 (rs3027898), NFKBIA (rs696) and NFKB1 (-94ATTG insertion/deletion variant, - rs28362491), in PV susceptibility. Forty-four unrelated patients with PV (23 males) were enrolled in the study. Additionally, 77 ethnic matching healthy volunteers (45 males) with no personal or family history of chronic autoimmune or infectious diseases were studied. Strong statistical significant difference was observed between PV patients and controls for polymorphism -94 insertion/deletion ATTG in the promoter region of NFKB1 gene (P = 0.00005). Additional dedicated studies in larger groups of patients of various ethnicities are needed to replicate and confirm the preliminary findings.

Skin cancer prevention: a review of current topical options complementary to sunscreens

The incidence of non-melanoma skin cancer (NMSC) is dramatically increasing worldwide, despite the increased use of improved sunscreens. In 2014, the Surgeon General estimated that 2.2-5.0 million people were treated annually for NMSC. As the number of newly diagnosed skin cancers continues to rise, there is a need for additional preventative measures beyond sunscreens. Several newer topical products that focus on boosting DNA repair, modulating DNA transcription, decreasing inflammation and selectively targeting precancerous cells may play an important role in future skin cancer prevention.

Role of Nicotinamide Adenine Dinucleotide and Related Precursors as Therapeutic Targets for Age-Related Degenerative Diseases: Rationale, Biochemistry, Pharmacokinetics, and Outcomes

Significance: Nicotinamide adenine dinucleotide (NAD+) is an essential pyridine nucleotide that serves as an essential cofactor and substrate for a number of critical cellular processes involved in oxidative phosphorylation and ATP production, DNA repair, epigenetically modulated gene expression, intracellular calcium signaling, and immunological functions. NAD+ depletion may occur in response to either excessive DNA damage due to free radical or ultraviolet attack, resulting in significant poly(ADP-ribose) polymerase (PARP) activation and a high turnover and subsequent depletion of NAD+, and/or chronic immune activation and inflammatory cytokine production resulting in accelerated CD38 activity and decline in NAD+ levels. Recent studies have shown that enhancing NAD+ levels can profoundly reduce oxidative cell damage in catabolic tissue, including the brain. Therefore, promotion of intracellular NAD+ anabolism represents a promising therapeutic strategy for age-associated degenerative diseases in general, and is essential to the effective realization of multiple benefits of healthy sirtuin activity. The kynurenine pathway represents the de novo NAD+ synthesis pathway in mammalian cells. NAD+ can also be produced by the NAD+ salvage pathway. Recent Advances: In this review, we describe and discuss recent insights regarding the efficacy and benefits of the NAD+ precursors, nicotinamide (NAM), nicotinic acid (NA), nicotinamide riboside (NR), and nicotinamide mononucleotide (NMN), in attenuating NAD+ decline in degenerative disease states and physiological aging. Critical Issues: Results obtained in recent years have shown that NAD+ precursors can play important protective roles in several diseases. However, in some cases, these precursors may vary in their ability to enhance NAD+ synthesis via their location in the NAD+ anabolic pathway. Increased synthesis of NAD+ promotes protective cell responses, further demonstrating that NAD+ is a regulatory molecule associated with several biochemical pathways. Future Directions: In the next few years, the refinement of personalized therapy for the use of NAD+ precursors and improved detection methodologies allowing the administration of specific NAD+ precursors in the context of patients' NAD+ levels will lead to a better understanding of the therapeutic role of NAD+ precursors in human diseases.

Acne RA-1,2, a novel UV-selective face cream for patients with acne: Efficacy and tolerability results of a randomized, placebo-controlled clinical study

BACKGROUND

General skincare measures such as the use of moisturisers and products containing adequate photoprotection are important components of acne patients' management to complement the pharmacological regimen. Acne RA-1,2 is a novel dermato-cosmetic product which contains selective photofilters and active ingredients against the multifactorial pathophysiology of acne.

OBJECTIVES

To evaluate the tolerability of Acne RA-1,2 and its effect on the clinical signs of acne.

METHODS

This double-blind, placebo-controlled study randomized 40 adult patients with 10-25 comedones per half face to once-daily application of Acne RA-1,2 or placebo for 8 weeks. Evaluations after 4 and 8 weeks included the number of comedones, transepidermal water loss (TEWL), sebum production, and tolerability.

RESULTS

In the Acne RA-1,2 group, there was a significant 35% decrease in the mean number of comedones from 26 at baseline to 17 at Week 8 (P<.001), a 7% significant reduction in TEWL (9.32 to 8.66 g/h/m² ; P<.001), and a 24% significant reduction in sebum production (154.8 to 117.6 μg/cm² ; P<.001). The reductions in TEWL and sebum production were significantly greater than those in the placebo group at Weeks 4 and 8 (P<0.05). There were no adverse events.

CONCLUSIONS

Acne RA-1,2 was well tolerated and effective at reducing comedones and sebum production and improving epidermal barrier function. These results suggest that Acne RA-1,2 is useful against acne-prone facial skin, particularly as it targets sebum production, which topical pharmacological acne therapies do not address.

The effect of two drug delivery systems in ropivacaine cytotoxicity and cytokine release by human keratinocytes and fibroblasts

Objectives

Modified drug delivery systems have been developed to improve pharmacological properties of local anaesthetics. However, the inflammatory potential of these formulations was not investigated. This study compared the in-vitro effects of ropivacaine (ropi) in plain, liposomal (MLV) or 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) formulations on cell viability, apoptosis and cytokine (IL-1α, TNF-α, IL-6 and IL-10) release.

Methods

Human immortalized keratinocytes (HaCaT) and human immortalized gingival fibroblasts (HGF) were exposed to 1–100 μm ropi concentrations. The cell viability was measured by XTT and LIVE/DEAD assay. Apoptosis was performed by flow cytometry, and cytokine release was measured by ELISA assay.

Key findings

Human immortalized keratinocyte viability was reduced by ropi and both drug delivery systems. However, none of the formulations induced apoptosis. Results showed a differential regulation of IL-1α TNF-α, IL-6 and IL-10 by HaCaT and HGF. Ropi-HP-β-CD increased twofold the IL-6 release by HGF in comparison with the control, while 100 μm ropi-MLV led to an increased release of all pro-inflammatory cytokines by HGF.

Conclusion

The loss in cell viability was not related to cellular apoptosis. Ropi complexed with HP-β-CD showed a similar cytokine release pattern when compared to the plain formulation. Thus, the HP-β-CD form was a better drug carrier than the MLV form for ropivacaine drug delivery.

Tolerability and camouflaging effect of corrective makeup for acne: results of a clinical study of a novel face compact cream

Background

A novel face compact cream (FCC) containing a new patented formulation was recently developed to provide acne patients with cosmetic camouflage for their lesions and to have beneficial effects on the multifactorial components of the disease. This pilot investigation aimed to evaluate the real-life tolerability, potential for comedogenicity and covering effect provided by this FCC.

Methods

This single-center study evaluated the FCC applied once daily for 28 days in 20 females with facial acne. Tolerability was assessed by rating skin reactions on a scale from 1 =absent to 4 =evident. Comedogenicity potential was evaluated by determining the number of facial acne lesions before and after use of the FCC. The covering effect was rated in ten patients 30 minutes after application on a scale from 1 =none to 5 =excellent. Patients rated their opinions on the FCC on day 28 using a questionnaire.

Results

Assessment of tolerability on days 0, 14, and 28 showed that skin reactions, including erythema, edema, dryness, desquamation, tight feeling, itching, and burning, were absent in all patients. The FCC was noncomedogenic and provided a significant 15.8% reduction in facial acne lesions after 28 days (P<0.001). The FCC provided a good covering effect 30 minutes after application in 80% of patients. All patients (100%) were satisfied with the FCC, with 90% agreeing that the FCC was effective and 80% stating that the FCC improved their skin.

Conclusion

The FCC was positively perceived, well tolerated, noncomedogenic, and provided an effective covering of acne in this small group of female patients with 1 month of follow-up.

Protective effect of Schizandrin B against damage of UVB irradiated skin cells depend on inhibition of inflammatory pathways

Schizandrin B is extracted from Schisandra chinensis (Turcz.) Baill. This study evaluated the photoprotective effect of Schizandrin B on oxidative stress injury of the skin caused by UVB-irradiation and the molecular mechanism of the photoprotective effect of Schizandrin B, and we firstly found that Schizandrin B could block Cox-2, IL-6 and IL-18 signal pathway to protect damage of skin cells given by UVB-irradiation. In the research, we found that Schizandrin B can attenuate the UVB-induced toxicity on keratinocytes and dermal fibroblasts in human body, and can outstandingly eliminated intracellular ROS produced by UVB-irradiation. These results demonstrate that Schizandrin B can regulate the function of decreasing intracellular SOD's activity and increasing the expression level of MDA in HaCaT cells result from the guidance of UVB, and it markedly reduced the production of inflammatory factors such as Cox-2, IL-6 or IL-18, decreased the expression level of MMP-1, and interdicted degradation process of collagens in UVB-radiated cells. Therefore, skin keratinocytes can be effectively protected from UVB-radiated damage by Schizandrin B, and UVB-irradiation caused inflammatory responses can be inhibited by attenuating process of ROS generating.

Cytokine patterns in cancer patients: A review of the correlation between interleukin 6 and prognosis

OBJECTIVE

In tumor patients, IL-6 appears to be one component of a consistent cancer-associated cytokine network resulting in both a systemic immune stimulation and a microenvironment of cancer-induced immune suppression that ultimately protects the cancer cells. IL-6 has been associated with prognosis in cancer patients, but so far a systemical analysis has not been carried out.

METHODS

The present meta-analysis studies the relation between IL-6 serum levels and the prognosis of cancer patients in the available clinical literature of 100 articles published between 1993 and 2013 comprising 11,583 patients.

RESULTS

The IL-6 serum level was described as significantly correlating with survival in 82/101 series comprising 85.6% of patients (9917/11,583) with 23 different cancer types. A total of 64 studies dichotomized patient cohorts according to various cut-off IL-6 serum levels: in 59/64 of these series corresponding to 94.5% of the reported patients (7694/8142) significant correlations between IL-6 serum level and survival were seen. The median survival of cancer patients had been determined above various cut-off levels of serum IL-6 in 24 dichotomized studies (26 cohorts). There was a highly significant inverse correlation between median survival of the cohorts with IL-6 serum level above cut-off (1272 patients) and their corresponding IL-6 cut-off values (Spearman R -0,48 p= < 0.001) following a linear regression when both parameters were log-transformed (p < 0.001). A significant correlation between increasing serum IL-6 and tumor stage or metastases was described in 39/44 studies and 91% of published patients (4221/4636) where clinical parameters had been specified.

CONCLUSIONS

Closely associated with the patient's clinical condition and independent of the cancer histology, the increased IL-6 serum level uniformly appears to correlate with survival as paraneoplastic condition in later cancer stages independent of the cancer type. Modifications of this paraneoplastic immune reaction may offer new therapeutic options in cancer.

A review of nicotinamide: treatment of skin diseases and potential side effects

Nicotinamide, also known as niacinamide, is the amide form of vitamin B3. It is a precursor of essential coenzymes for numerous reactions in the body including adenosine triphosphate (ATP) production. Nicotinic acid, also known as niacin, is converted into nicotinamide in the body. The use of topical nicotinamide in the treatment of acne vulgaris; melasma; atopic dermatitis; rosacea; and oral nicotinamide in preventing nonmelanoma skin cancer is discussed. The possible side effects and consequences of excessive nicotinamide exposure are reviewed, including suggestions nicotinamide might have a role in the development of diabetes, Parkinson's disease, and liver damage.

Anti-inflammatory properties of low and high doxycycline doses: an in vitro study

Doxycycline is used to treat infective diseases because of its broadspectrum efficacy. High dose administration (100 or 200 mg/day) is often responsible for development of bacterial resistances and endogenous flora alterations, whereas low doses (20–40 mg/day) do not alter bacteria susceptibility to antibiotics and exert anti-inflammatory activities. In this study, we wanted to assess the efficacy of both low and high doxycycline doses in modulating IL-8, TNF-α, and IL-6 gene expression in HaCaT cells stimulated with LPS. Three experimental settings were used, differing in the timing of doxycycline treatment in respect to the insult induced by LPS: pretreatment, concomitant, and posttreatment. Low doses were more effective than high doses in modulating gene expression of LPS-induced proinflammatory cytokines (IL-8, TNF-α, and IL-6), when added before (pretreatment) or after (posttreatment) LPS stimulation. This effect was not appreciated when LPS and doxycycline were simultaneously added to cell cultures: in this case high doses were more effective. In conclusion, our in vitro study suggests that low doxycycline doses could be safely used in chronic or acute skin diseases in which the inflammatory process, either constantly in progress or periodically recurring, has to be prevented or controlled.

The modulatory effect of ellagic acid and rosmarinic acid on ultraviolet-B-induced cytokine/chemokine gene expression in skin keratinocyte (HaCaT) cells

Ultraviolet radiation (UV) induces an increase in multiple cutaneous inflammatory mediators. Ellagic acid (EA) and rosmarinic acid (RA) are natural anti-inflammatory and immunomodulatory compounds found in many plants, fruits, and nuts. We assessed the ability of EA and RA to modulate IL-1β, IL-6, IL-8, IL-10, MCP-1, and TNF-α gene expression in HaCaT cells after UVB irradiation. Cells were treated with UVB (100 mJ/cm(2)) and simultaneously with EA (5 μM in 0.1% DMSO) or RA (2.7 μM in 0.5% DMSO). Moreover, these substances were added to the UVB-irradiated cells 1 h or 6 h before harvesting, depending on the established UVB-induced cytokine expression peak. Cytokine gene expression was examined using quantitative real time polymerase chain reaction. RA produced a significant reduction in UVB-induced expression of IL-6, IL-8, MCP-1, and TNF-α when applied at the same time as irradiation. EA showed milder effects compared with RA, except for TNF-α. Both substances decreased IL-6 expression, also when applied 5 h after irradiation, and always produced a significant increase in UVB-induced IL-10 expression. Our findings suggest that EA and RA are able to prevent and/or limit the UVB-induced inflammatory cascade, through a reduction in proinflammatory mediators and the enhancement of IL-10, with its protective function.

Barrier protective use of skin care to prevent chemotherapy-induced cutaneous symptoms and to maintain quality of life in patients with breast cancer

Purpose

Chemotherapy with anthracyclines, taxanes, or alkylating agents often causes cutaneous side effects. Nonspecific inhibition of the proliferative activity of keratinocytes has antidifferentiation effects that lead to defects in the barrier function and, thus, to dry, itchy, and irritable skin. These cutaneous symptoms reduce the quality of life of the patients considerably. Conditioning with topical application of niacinamide uses the cytoprotective and barrier stabilizing effect of vitamin B₃.

Patients and methods

A multicenter randomized crossover study investigated the influence of the test preparation on the quality of life compared to standard care for 73 patients with breast cancer undergoing adjuvant or neoadjuvant cytostatic therapy. Primary target parameter was the Dermatology Life Quality Index with its respective subscales after 6 weeks of a twice-daily application of the respective preparations. Additionally, specific symptoms such as pruritus, dryness, and irritability have been assessed using visual analog scales.

Results

Regarding the total score of the Dermatology Life Quality Index, no relevant differences could be observed. However, the results for the “symptoms and feelings” subscale show a significant advantage in favor of the test preparation. Significant superiority of the test preparation could also be observed in the secondary target parameters, the visual analog scales (P<0.05).

Conclusion

The results show for the first time a significant superiority of prophylactic application of niacinamide for maintaining quality of life while undergoing cytostatic treatment.

The evolving role of the NAD+/nicotinamide metabolome in skin homeostasis, cellular bioenergetics, and aging

Human skin is exposed to daily environmental insults, particularly solar radiation, that triggers a range of molecular responses. These perturbations to the normal homeostatic state can lead to cellular dysfunction and, ultimately, impacts tissue integrity and accelerates skin aging (photoaging). One of the responses is increased oxidative stress which has been shown to disrupt cellular bioenergetics. This can be detected by depletion of the nucleotide energy metabolites NAD+ and ATP as both an acute transient decrease and, over time, a more permanent chronic reduction due in part to cumulative damage of mitochondria. NAD+ and its primary precursor nicotinamide have been known for some time to impact skin homeostasis based on linkages to dietary requirements, treatment of various inflammatory conditions, photoaging, and prevention of cancer. Cellular NAD+ pools are known to be lower in aged skin and treatment with nicotinamide is hypothesized to restore these levels, thereby mitigating cellular bioenergetics dysfunction. In dermal fibroblasts, nicotinamide is able to protect against oxidative stress to glycolysis, oxidative phosphorylation as well as increase mitochondrial efficiency via sirtuin-dependent selective mitophagy. Recent research has found that NAD+ cellular pools are more dynamic than previously thought, oscillating in tandem with free nicotinamide, and serves as a regulatory point and feedback loop in cellular metabolism regulation, maintenance of mitochondrial efficiency, and circadian rhythmicity. Since UV-induced oxidative stress in skin can disrupt these processes, continued molecular understanding of the role of NAD+ and nicotinamide in skin biology is important to identify interventions that would help maintain its normal homeostatic functions and efficient cellular bioenergetics.

UVB-irradiated keratinocytes induce melanoma-associated ganglioside GD3 synthase gene in melanocytes via secretion of tumor necrosis factor α and interleukin 6

Although expression of gangliosides and their synthetic enzyme genes in malignant melanomas has been well studied, that in normal melanocytes has been scarcely analyzed. In particular, changes in expression levels of glycosyltransferase genes responsible for ganglioside synthesis during evolution of melanomas from melanocytes are very important to understand roles of gangliosides in melanomas. Here, expression of glycosyltransferase genes related to the ganglioside synthesis was analyzed using RNAs from cultured melanocytes and melanoma cell lines. Quantitative RT-PCR revealed that melanomas expressed high levels of mRNA of GD3 synthase and GM2/GD2 synthase genes and low levels of GM1/GD1b synthase genes compared with melanocytes. As a representative exogenous stimulation, effects of ultraviolet B (UVB) on the expression levels of 3 major ganglioside synthase genes in melanocytes were analyzed. Although direct UVB irradiation of melanocytes caused no marked changes, culture supernatants of UVB-irradiated keratinocytes (HaCaT cells) induced definite up-regulation of GD3 synthase and GM2/GD2 synthase genes. Detailed examination of the supernatants revealed that inflammatory cytokines such as TNFα and IL-6 enhanced GD3 synthase gene expression. These results suggest that inflammatory cytokines secreted from UVB-irradiated keratinocytes induced melanoma-associated ganglioside synthase genes, proposing roles of skin microenvironment in the promotion of melanoma-like ganglioside profiles in melanocytes.

Activin a inhibits antigen-induced allergy in murine epicutaneous sensitization

Activin A, a member of the TGFβ superfamily, is involved in physiological processes such as cell differentiation, tissue homeostasis, wound healing, reproduction, and in pathological conditions, such as fibrosis, cancer, and asthma. Activin enhances mast cell maturation, as well as regulatory T-cell and Langerhans cell differentiation. In this study we investigated the potential role of activin in epicutaneous sensitization with ovalbumin (OVA), notably with respect to its effect on known Th2-polarization. For this purpose, transgenic mice overexpressing activin in keratinocytes and their wild-type (WT) controls were sensitized epicutaneously with OVA. Skin biopsies were analyzed with regard to histopathological features and mRNA expression of pro-inflammatory and Th1/Th2 cytokines, and Ig levels were measured in the serum. Unexpectedly, activin overexpressing animals were protected from Th2-cytokine expression and induction of OVA-specific IgE levels compared to WT animals. On the other hand, transgenic mice were more susceptible to inflammation compared to WT littermates after tape-stripping and saline (vehicle) or OVA application, as shown by increased pro-inflammatory cytokine mRNA levels and neutrophil accumulation at the site of the treatment. We conclude that activin protects from antigen-induced cutaneous Th2-polarization through modulation of the immune response. These findings highlight the role of activin in cutaneous sensitization, allergy, and in skin homeostasis.