Nicotinamide and the skin

Putative mechanism of a multivitamin treatment against insulin resistance

Insulin resistance is caused by the abnormal secretion of proinflammatory cytokines in adipose tissue, which is induced by an increase in lipid accumulation in adipocytes, hepatocytes, and myocytes. The inflammatory pathway involves multiple targets such as nuclear factor kappa B, inhibitor of nuclear factor κ-B kinase, and mitogen-activated protein kinase. Vitamins are micronutrients with anti-inflammatory activities that have unclear mechanisms. The present study aimed to describe the putative mechanisms of vitamins involved in the inflammatory pathway of insulin resistance. The strategy to achieve this goal was to integrate data mining and analysis, target prediction, and molecular docking simulation calculations to support our hypotheses. Our results suggest that the multitarget activity of vitamins A, B1, B2, B3, B5, B6, B7, B12, C, D3, and E inhibits nuclear factor kappa B and mitogen-activated protein kinase, in addition to vitamins A and B12 against inhibitor of nuclear factor κ-B kinase. The findings of this study highlight the pharmacological potential of using an anti-inflammatory and multitarget treatment based on vitamins and open new perspectives to evaluate the inhibitory activity of vitamins against nuclear factor kappa B, mitogen-activated protein kinase, and inhibitor of nuclear factor κ-B kinase in an insulin-resistant context.

Decreasing Intracellular Entropy by Increasing Mitochondrial Efficiency and Reducing ROS Formation-The Effect on the Ageing Process and Age-Related Damage

A hypothesis is presented to explain how the ageing process might be influenced by optimizing mitochondrial efficiency to reduce intracellular entropy. Research-based quantifications of entropy are scarce. Non-equilibrium metabolic reactions and compartmentalization were found to contribute most to lowering entropy in the cells. Like the cells, mitochondria are thermodynamically open systems exchanging matter and energy with their surroundings-the rest of the cell. Based on the calculations from cancer cells, glycolysis was reported to produce less entropy than mitochondrial oxidative phosphorylation. However, these estimations depended on the CO2 concentration so that at slightly increased CO2, it was oxidative phosphorylation that produced less entropy. Also, the thermodynamic efficiency of mitochondrial respiratory complexes varies depending on the respiratory state and oxidant/antioxidant balance. Therefore, in spite of long-standing theoretical and practical efforts, more measurements, also in isolated mitochondria, with intact and suboptimal respiration, are needed to resolve the issue. Entropy increases in ageing while mitochondrial efficiency of energy conversion, quality control, and turnover mechanisms deteriorate. Optimally functioning mitochondria are necessary to meet energy demands for cellular defence and repair processes to attenuate ageing. The intuitive approach of simply supplying more metabolic fuels (more nutrients) often has the opposite effect, namely a decrease in energy production in the case of nutrient overload. Excessive nutrient intake and obesity accelerate ageing, while calorie restriction without malnutrition can prolong life. Balanced nutrient intake adapted to needs/activity-based high ATP requirement increases mitochondrial respiratory efficiency and leads to multiple alterations in gene expression and metabolic adaptations. Therefore, rather than overfeeding, it is necessary to fine-tune energy production by optimizing mitochondrial function and reducing oxidative stress; the evidence is discussed in this paper.

Beneficial Effects of Multi-Micronutrient Supplementation with Collagen Peptides on Global Wrinkles, Skin Elasticity and Appearance in Healthy Female Subjects

INTRODUCTION

With ageing, collagen production slows down, leading to wrinkle appearance and loss of elasticity. Replenishing key structural molecules through oral supplementation is a promising strategy that complements the topical delivery of cosmetic products and creates a holistic skincare regimen. The present study assessed the effectiveness of a food supplement with collagen peptides, vitamins and minerals in improving the quality of the skin and general wellbeing of healthy women.

METHODS

This was an open-label study of 135 women aged between 45 and 65 years. A 3-month treatment phase followed a 4-week washout phase, with visits scheduled at baseline and after each month of treatment. Subjects received three tablets of Richelet Skin Renewal daily. The primary outcome was change from baseline to month 3 in global wrinkles score by expert grader analysis. Secondary outcomes included changes in skin elasticity and other skin attributes, product assessment via self-perception questionnaires and total antioxidant status.

RESULTS

A total of 116 subjects completed the study. The mean global wrinkles score indicated a statistically significant decrease from 5.9 at baseline to 5.0 at month 3 (p < 0.0001), with 83.6% of subjects showing an improvement; significant changes were reported at all intermediate visits. The increase in skin elasticity was also statistically significant (R2 score 0.74 at month 3; p < 0.0001). All subjects (100%) demonstrated significant improvements in skin texture, skin tone evenness, skin radiance and overall skin quality at the month 3 visit.

CONCLUSIONS

The study product achieved statistically significant, noticeable effects on global wrinkles, skin elasticity and a range of skin attributes after 3 months of use in healthy women. These results strengthen the evidence for supplementation of collagen peptides and other micronutrients as an effective component of anti-ageing skincare.

Cutaneous Squamous Cell Carcinoma: An Updated Review

Representing the second most common skin cancer, the incidence and disease burden of cutaneous squamous cell carcinoma (cSCC) continues to increase. Surgical excision of the primary site effectively cures the majority of cSCC cases. However, an aggressive subset of cSCC persists with clinicopathological features that are indicative of higher recurrence, metastasis, and mortality risks. Acceleration of these features is driven by a combination of genetic and environmental factors. The past several years have seen remarkable progress in shaping the treatment landscape for advanced cSCC. Risk stratification and clinical management is a top priority. This review provides an overview of the current perspectives on cSCC with a focus on staging, treatment, and maintenance strategies, along with future research directions.

Role of epigenetics in the regulation of skin aging and geroprotective intervention: A new sight

Multiple epigenetic factors play a regulatory role in maintaining the homeostasis of cutaneous components and are implicated in the aging process of the skin. They have been associated with the activation of the senescence program, which is the primary contributor to age-related decline in the skin. Senescent species drive a series of interconnected processes that impact the immediate surroundings, leading to structural changes, diminished functionality, and heightened vulnerability to infections. Geroprotective medicines that may restore the epigenetic balance represent valid therapeutic alliances against skin aging. Most of them are well-known Western medications such as metformin, nicotinamide adenine dinucleotide (NAD+), rapamycin, and histone deacetylase inhibitors, while others belong to Traditional Chinese Medicine (TCM) remedies for which the scientific literature provides limited information. With the help of the Geroprotectors.org database and a comprehensive analysis of the referenced literature, we have compiled data on compounds and formulae that have shown potential in preventing skin aging and have been identified as epigenetic modulators.

Study on the Skincare Effects of Red Rice Fermented by Aspergillus oryzae In Vitro

Red rice, a variety of pigmented grain, serves dual purposes as both a food and medicinal resource. In recent years, we have witnessed an increasing interest in the dermatological benefits of fermented rice extracts, particularly their whitening and hydrating effects. However, data on the skincare advantages derived from fermenting red rice with Aspergillus oryzae remain sparse. This study utilized red rice as a substrate for fermentation by Aspergillus oryzae, producing a substance known as red rice Aspergillus oryzae fermentation (RRFA). We conducted a preliminary analysis of RRFA's composition followed by an evaluation of its skincare potential through various in vitro tests. Our objective was to develop a safe and highly effective skincare component for potential cosmetic applications. RRFA's constituents were assessed using high-performance liquid chromatography (HPLC), Kjeldahl nitrogen determination, the phenol-sulfuric acid method, and enzyme-linked immunosorbent assay (ELISA). We employed human dermal fibroblasts (FB) to assess RRFA's anti-aging and antioxidative properties, immortalized keratinocytes (HaCaT cells) and 3D epidermal models to examine its moisturizing and reparative capabilities, and human primary melanocytes (MCs) to study its effects on skin lightening. Our findings revealed that RRFA encompasses several bioactive compounds beneficial for skin health. RRFA can significantly promote the proliferation of FB cells. And it markedly enhances the mRNA expression of ECM-related anti-aging genes and reduces reactive oxygen species production. Furthermore, RRFA significantly boosts the expression of Aquaporin 3 (AQP3), Filaggrin (FLG), and Hyaluronan Synthase 1 (HAS1) mRNA, alongside elevating moisture levels in a 3D epidermal model. Increases were also observed in the mRNA expression of Claudin 1 (CLDN1), Involucrin (IVL), and Zonula Occludens-1 (ZO-1) in keratinocytes. Additionally, RRFA demonstrated an inhibitory effect on melanin synthesis. Collectively, RRFA contains diverse ingredients which are beneficial for skin health and showcases multifaceted skincare effects in terms of anti-aging, antioxidant, moisturizing, repairing, and whitening capabilities in vitro, highlighting its potential for future cosmetic applications.

Analysis of a Combination Therapy Protocol for the Treatment of Oral Mucous Membrane Pemphigoid: A Retrospective Case Series Study

Mucous membrane pemphigoid (MMP) is an autoimmune-based bullous disease affecting the mucous membranes, mainly oral and ocular. One of the most common clinical manifestations is desquamative gingivitis (DG), characterized by intense symptoms and functional limitations. The dentist is among the first specialists to observe DG and, therefore, must be able to diagnose it. In this regard, the purpose of the present study was to evaluate the efficacy and safety of a clinical protocol for the topical management of patients with DG and MMP buccal lesions. Thirteen patients with clinical and histologic diagnoses of MMP-localized DG in the oral cavity were retrospectively enrolled. Each patient received topical treatment with clobetasol propionate oral gel 0.05%; nicotinamide; oral probiotic (contains Bifidobacterium lactis HN019, Kluyveromyces marxianus fragilis B0399, colostrum, and biotin); and doxycycline. Before and after 3 months of therapy, clinic records were collected for each patient. Seven patients (53.8%) had a complete response to treatment; four patients (30.8%) had a partial response to treatment; and, finally, two patients (15.4%) had no benefit from therapy. Dental management of patients presenting solely with oral manifestations of MMP may involve the use of topical corticosteroids, doxycycline, vitamin supplements, and probiotics and associating professional oral hygiene procedures.

A Dermocosmetic Significantly Reduces the Frequency and Intensity of Facial Skin Intolerability and Sensitivity in Subjects with Skin Intolerant to Skin Care Products and Sensitive Skin

Introduction

Intolerance to dermocosmetics is frequent in subjects with allergic contact dermatitis (ACD). A dermocosmetic (DC) was developed to restore the natural skin barrier, to reduce skin inflammation and to improve sensitive skin in ACD.

Objective

To assess the benefit of a DC in subjects with an allergic background and intolerance to cosmetic care, or with sensitive skin.

Materials and Methods

In this open-label study, 107 subjects above 16 years of age applied DC on the face twice a day for 28 days. Assessments at Days 0, 14 and 28, included skin sensitivity, stinging test, local tolerance, transepidermal water loss (TEWL), skin hydration, inflammatory biomarkers (IL-1α, IL-1RA, PGE2) using tape stripping and subject satisfaction.

Results

88% were women and mean age was 42.0±15.0 years. Skin sensitivity at inclusion scored 5.9±0.35; 46% had ACD, 95% skin irritation, 92% sensitive skin and 88% intolerance to cosmetics. A significant (p<0.0001) 85% decrease of frequency and intensity of the composite score was observed at both endpoints. Stinging scores significantly (p<0.0001) decreased from 3.9 at baseline to 2.4 at Day 14 and 1.4 at Day 28; 77% and 81% of subjects reported improved skin reactivity at Day 14 and Day 28, respectively. Similar improvements were noted in the frequency and intensity of irritation, erythema, stinging, burning and discomfort. TEWL, skin hydration and inflammatory biomarker levels significantly (p<0.0001) improved. Overall subject satisfaction (85%) and tolerance (investigators: 99%, subjects: 97%) were high.

Conclusion

DC significantly reduced the frequency and intensity of facial skin intolerability and sensitivity in subjects with skin intolerant to skin care products.

Clinicaltrialsgov Identifier

NCT05487937.

Oral nicotinamide for non-melanoma skin cancers: A review

There has been much interest in the role of oral nicotinamide supplementation in reducing the incidence of non-melanoma skin cancers. This article reviews the hypothesised mechanisms of action of nicotinamide, and the available literature outlining its role for this purpose. There have been five randomised controlled trials (RCT), one histopathological study and two case series exploring the effect of oral nicotinamide supplementation on UV-induced immunosuppression of the skin, and incidence of actinic keratoses and non-melanoma skin cancers (NMSC). The largest RCT received criticism of the statistical analyses used, but the critics still acknowledged a likely benefit of treatment with oral nicotinamide in reducing the incidence of NMSC. Nicotinamide has a favourable safety profile. Current evidence is not definitive that oral nicotinamide supplementation reduces the incidence of NMSC, but it constitutes a low-risk management option that may be particularly relevant for high-risk individuals, and should be discussed as an option for these patients.

The Central Role of the NAD+ Molecule in the Development of Aging and the Prevention of Chronic Age-Related Diseases: Strategies for NAD+ Modulation

The molecule NAD+ is a coenzyme for enzymes catalyzing cellular redox reactions in several metabolic pathways, encompassing glycolysis, TCA cycle, and oxidative phosphorylation, and is a substrate for NAD+-dependent enzymes. In addition to a hydride and electron transfer in redox reactions, NAD+ is a substrate for sirtuins and poly(adenosine diphosphate-ribose) polymerases and even moderate decreases in its cellular concentrations modify signaling of NAD+-consuming enzymes. Age-related reduction in cellular NAD+ concentrations results in metabolic and aging-associated disorders, while the consequences of increased NAD+ production or decreased degradation seem beneficial. This article reviews the NAD+ molecule in the development of aging and the prevention of chronic age-related diseases and discusses the strategies of NAD+ modulation for healthy aging and longevity.

Grafting natural nicotinamide on tempo-oxidized cellulose nanofibrils to prepare flexible and transparent nanocomposite films with fascinating mechanical strength and UV shielding performance

Light pollution from ultraviolet (UV) radiation is gaining growing concerns, as the emissions and burning of fossil fuels destroyed the ozone layer. Seeking a solution against skin exposure to excessive radiation is an urgent requirement. In this study, nicotinamide (NA), the main component of vitamin B3, was introduced as a new modifier into Tempo-oxidized cellulose nanofibrils (TOCNFs) together with the physical cross-linking with tannin acid (TA) to improve anti-UV performance of the nanocomposite films. Incorporation of NA into the films presents distinguished UV shielding capability UVB wavelength range from 200 nm to 320 nm (NTA1-5) due to the introduced functional groups like CO and benzene rings. Moreover, mechanical properties were notably enhanced, which overcome the low strength of common nanocellulosic materials. The stress increased from 69.8 MPa to 116.3 MPa, and the toughness can reach 131.58 MJ/m³ by tuning the additional amount of NA. Meanwhile, TGA and DTG analysis demonstrated that the incorporation of amide bonds and TA into the composite films greatly improved the thermal stability. Thus, the proposed materials fabricated from natural biomolecules show great potential in serving as new kinds of UV-resistant products in the application areas of sunscreen, protective clothing, and building materials.

Current Uncertainties and Future Challenges Regarding NAD+ Boosting Strategies

Precursors of nicotinamide adenine dinucleotide (NAD+), modulators of enzymes of the NAD+ biosynthesis pathways and inhibitors of NAD+ consuming enzymes, are the main boosters of NAD+. Increasing public awareness and interest in anti-ageing strategies and health-promoting lifestyles have grown the interest in the use of NAD+ boosters as dietary supplements, both in scientific circles and among the general population. Here, we discuss the current trends in NAD+ precursor usage as well as the uncertainties in dosage, timing, safety, and side effects. There are many unknowns regarding pharmacokinetics and pharmacodynamics, particularly bioavailability, metabolism, and tissue specificity of NAD+ boosters. Given the lack of long-term safety studies, there is a need for more clinical trials to determine the proper dose of NAD+ boosters and treatment duration for aging prevention and as disease therapy. Further research will also need to address the long-term consequences of increased NAD+ and the best approaches and combinations to increase NAD+ levels. The answers to the above questions will contribute to the more efficient and safer use of NAD+ boosters.

Superior even skin tone and anti-ageing benefit of a combination of 4-hexylresorcinol and niacinamide

Objectives

To demonstrate the synergistic effect of 4‐hexylresorcinol (4‐HR) with niacinamide in boosting anti‐melanogenic efficacy in vitro and establish the in vivo efficacy and safety of the combination in a human trial.

Methods

Primary human epidermal melanocytes and 3D pigmented skin equivalents were treated with 4‐HR, niacinamide, and their combinations for their effect on pigmentation. This was followed by a randomized, double‐blind, split‐face clinical study in Chinese subjects, and effects on skin tone, hyperpigmentation, fine lines and wrinkles, hydration, and skin firmness were measured for a 12‐week study period.

Results

In vitro tyrosinase enzyme activity studies showed that 4‐HR is one of the most potent tyrosinase inhibitors. The combination of 4‐HR and niacinamide showed a synergistic reduction in melanin production in cultured melanocytes and lightened the 3D skin equivalent model. In vitro as well as in the human trial, the combination of 4‐HR and niacinamide showed significantly improved efficacy over niacinamide alone on hyperpigmentation spots as measured by L*, the visual appearance of fine lines and wrinkles in crow's feet and perioral area and skin firmness, with no product‐related adverse events.

Conclusions

A formulation containing a combination of 4‐HR and niacinamide delivered superior skin tone and anti‐ageing benefits significantly better than niacinamide alone with no adverse events. This study demonstrates that a product designed to affect multiple pathways of melanogenesis, inflammation, and ageing may provide an additional treatment option, beyond hydroquinone and retinoids, for hyperpigmentation and ageing.

Topical Delivery of Niacinamide to Skin Using Hybrid Nanogels Enhances Photoprotection Effect

Niacinamide (NIA) has been widely used in halting the features of ageing by acting as an antioxidant and preventing dehydration. NIA’s physicochemical properties suggest difficulties in surpassing the barrier imposed by the stratum corneum layer to reach the target in the skin. To improve cutaneous delivery of NIA, a hybrid nanogel was designed using carrageenan and polyvinylpyrrolidone polymers combined with jojoba oil as a permeation enhancer. Three different types of transethosomes were prepared by the thin-film hydration method, made distinct by the presence of either an edge activator or a permeation enhancer, to allow for a controlled delivery of NIA. Formulations were characterized by measurements of size, polydispersity index, zeta potential, encapsulation efficiency, and loading capacity, and by evaluating their chemical interactions and morphology. Skin permeation assays were performed using Franz diffusion cells. The hybrid hydrogels exhibited robust, porous, and highly aligned macrostructures, and when present, jojoba oil changed their morphology. Skin permeation studies with transethosomes-loaded hydrogels showed that nanogels per se exhibit a more controlled and enhanced permeation, in particular when jojoba oil was present in the transethosomes. These promising nanogels protected the human keratinocytes from UV radiation, and thus can be added to sunscreens or after-sun lotions to improve skin protection.

Kinetics of the Release of Nicotinamide Absorbed on Partially Neutralized Poly(acrylic-co-methacrylic acid) Xerogel under the Conditions of Simultaneous Microwave Heating and Cooling

The kinetics of release of nicotinamide (NIAM) that was absorbed on partially neutralized poly(acrylic-co-methacrylic) (PAM) xerogel/hydrogel, under the conditions of simultaneous microwave heating and cooling (SMHC) were examined. The kinetics curves of NIAM release into an aqueous solution at temperatures of 308-323 K were recorded. By applying the model-fitting method (MFM), it was found that the kinetics of NIAM release can be modeled by a kinetic model of a first-order chemical reaction. The values of the release rate constants (k_M) at different temperatures were calculated, and their values were found to be within the range 8.4 10^-3 s ^-1-15.7 10^-3 s^-1. It has been established that the Arrhenius equation was valid even in the conditions of SMHC. The values of the kinetic parameters (activation energy (Ea) and pre-exponential factor (A) of the NIAM release process adsorbed on PAM xerogel/hydrogel were calculated as follows: Ea = 25.6 kJ/mol and ln (A/s^-1) = 5.21. It has been proven that the higher value of the rate constant at SMHC in relation to CH is not a consequence of the overheating of the reaction system or the appearance of "hot-points". The values of change of the enthalpy of activation (ΔH*) and the change of entropy of activation (ΔS*) were calculated as follows: ΔH* = +23.82 kJ/mol and ΔS* = -201.4 J/mol K. The calculated higher values of the kinetic parameters and thermodynamic parameters of activation are explained by the formation of a specific activated complex under SMHC, whose structure and degree of order are different than in the one formed under CH.

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.

Beyond Nicotinamide Metabolism: Potential Role of Nicotinamide N-Methyltransferase as a Biomarker in Skin Cancers

Skin cancers (SC) collectively represent the most common type of malignancy in white populations. SC includes two main forms: malignant melanoma and non-melanoma skin cancer (NMSC). NMSC includes different subtypes, namely, basal cell carcinoma (BCC), squamous cell carcinoma (SCC), Merkel cell carcinoma (MCC), and keratoacanthoma (KA), together with the two pre-neoplastic conditions Bowen disease (BD) and actinic keratosis (AK). Both malignant melanoma and NMSC are showing an increasing incidence rate worldwide, thus representing an important challenge for health care systems, also because, with some exceptions, SC are generally characterized by an aggressive behavior and are often diagnosed late. Thus, identifying new biomarkers suitable for diagnosis, as well as for prognosis and targeted therapy is mandatory. Nicotinamide N-methyltransferase (NNMT) is an enzyme that is emerging as a crucial player in the progression of several malignancies, while its substrate, nicotinamide, is known to exert chemopreventive effects. Since there is increasing evidence regarding the involvement of this enzyme in the malignant behavior of SC, the current review aims to summarize the state of the art as concerns NNMT role in SC and to support future studies focused on exploring the diagnostic and prognostic potential of NNMT in skin malignancies and its suitability for targeted therapy.

Theoretical Study of Retinol, Niacinamide and Glycolic Acid with Halloysite Clay Mineral as Active Ingredients for Topical Skin Care Formulations

The adsorption of retinol, niacinamide and glycolic acid active ingredients on the internal surface of halloysite in an aqueous environment was explored at the molecular level by means of calculations based on quantum mechanics and force fields from empirical interatomic potentials. These active ingredients are stably adsorbed on the internal surface of halloysite forming hydrogen bonds between the hydrogen, oxygen and nitrogen atoms with the hydroxyl groups of the inner surface of the halloysite. In addition, electrostatic interaction between these active ingredients with the water molecules was observed. Therefore, the theoretical results indicate that the adsorption of these active principles is favourable in the halloysite nanotube, which allows directing future experimental investigations for the development and design of retinol, niacinamide and glycolic acid with halloysite nanotubes systems, which may be topical formulations for skincare.

Water-in-oil microemulsions composed of monoolein enhanced the transdermal delivery of nicotinamide

OBJECTIVE

Nicotinamide, also known as niacinamide, is a water-soluble vitamin that is used to prevent and treat acne and pellagra. It is often found in water-based skin care cosmetics because of its high water solubility. Nicotinamide is a small molecule with a molar mass of 122.1 g/mol. However, it has a hydrophilic nature that becomes an obstacle when it penetrates through the skin. The topmost layer of the skin, the stratum corneum, acts as a strong hydrophobic barrier for such hydrophilic molecules. The oil-based formulations are expected to enhance the transdermal delivery efficiency of nicotinamide.

METHODS

We have developed oil-based microemulsion formulations composed of a squalane vehicle. Monoolein was used as an emulsifier that has a potential to enhance the nicotinamide delivery through the stratum corneum.

RESULTS

Because the mean size of the emulsions measured by dynamic light scattering was 20.9 ± 0.4 nm, the microemulsion formulation was stable under the long-term storage. Monoolein acted as a skin penetration enhancer, and it effectively enabled the penetration of nicotinamide through human abdominal skin, compared with nicotinamide in a phosphate-buffered saline solution. The flux was increased 25-fold. Microscopic imaging revealed that the hydrophilic bioactive compounds penetrated through the intercellular spaces in the epidermis.

CONCLUSION

The monoolein-based microemulsion was transparent and stable, suggesting that it is a promising formulation for a transdermal nicotinamide delivery.

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.

Healthy Lifestyle Recommendations: Do the Beneficial Effects Originate from NAD+ Amount at the Cellular Level?

In this review, we describe the role of oxidized forms of nicotinamide adenine dinucleotide (NAD⁺) as a molecule central to health benefits as the result from observing selected healthy lifestyle recommendations. Namely, NAD⁺ level can be regulated by lifestyle and nutrition approaches such as fasting, caloric restriction, sports activity, low glucose availability, and heat shocks. NAD⁺ is reduced with age at a cellular, tissue, and organismal level due to inflammation, defect in NAMPT-mediated NAD⁺ biosynthesis, and the PARP-mediated NAD⁺ depletion. This leads to a decrease in cellular energy production and DNA repair and modifies genomic signalling leading to an increased incidence of chronic diseases and ageing. By implementing healthy lifestyle approaches, endogenous intracellular NAD⁺ levels can be increased, which explains the molecular mechanisms underlying health benefits at the organismal level. Namely, adherence to here presented healthy lifestyle approaches is correlated with an extended life expectancy free of major chronic diseases.

Cosmeceutical Aptitudes of Niacinamide: A Review

BACKGROUND

The prevalence and scope of dermatological illness differ from region to region. Based upon type and severity, the conditions may vary from superficial to deep systemic skin infections. Niacinamide, an amide analog of vitamin B3 which was conventionally utilized as a food supplement, is now explored for the management of skin disorders. Being a powerhouse on its own, it is not stored inside the body naturally and has to be acquired from external sources. Areas Covered: This review is an attempt to disclose the physiology, pharmacology, and highlight the dermatological potentials of niacinamide, discussing its pharmacological mechanisms, varied commercially available treatments, and novel approaches, i.e., in research and patented formulations.

RESULTS

Niacinamide has been verified in treating almost every skin disorder, viz. aging, hyperpigmentation, acne, psoriasis, pruritus, dermatitis, fungal infections, epidermal melasma, non-melanoma skin cancer, etc. It has been reported to possess numerous properties, for instance, anti-inflammatory, antimicrobial, antioxidant, antipruritic, and anticancer, which makes it an ideal ingredient for varied dermal therapies. Long term use of niacinamide, regardless of the skin type, paves the way for new skin cells, making skin healthier, brighter, and hydrated.

CONCLUSION

Niacinamide possesses a variety of positive characteristics in the field of dermatology. Novel approaches are warranted over current treatments which could bypass the above shortcomings and form an effective and stable system. Hence, niacinamide has the potential to become an individual and a productive component with wide future scope.

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.

Nicotinamide inhibits melanoma in vitro and in vivo

Background

Even though new therapies are available against melanoma, novel approaches are needed to overcome resistance and high-toxicity issues. In the present study the anti-melanoma activity of Nicotinamide (NAM), the amide form of Niacin, was assessed in vitro and in vivo.

Methods

Human (A375, SK-MEL-28) and mouse (B16-F10) melanoma cell lines were used for in vitro investigations. Viability, cell-death, cell-cycle distribution, apoptosis, Nicotinamide Adenine Dinucleotide⁺ (NAD⁺), Adenosine Triphosphate (ATP), and Reactive Oxygen Species (ROS) levels were measured after NAM treatment. NAM anti-SIRT2 activity was tested in vitro; SIRT2 expression level was investigated by in silico transcriptomic analyses. Melanoma growth in vivo was measured in thirty-five C57BL/6 mice injected subcutaneously with B16-F10 melanoma cells and treated intraperitoneally with NAM. Interferon (IFN)-γ-secreting murine cells were counted with ELISPOT assay. Cytokine/chemokine plasmatic levels were measured by xMAP technology. Niacin receptors expression in human melanoma samples was also investigated by in silico transcriptomic analyses.

Results

NAM reduced up to 90% melanoma cell number and induced: i) accumulation in G1-phase (40% increase), ii) reduction in S- and G2-phase (about 50% decrease), iii) a 10-fold increase of cell-death and 2.5-fold increase of apoptosis in sub-G1 phase, iv) a significant increase of NAD⁺, ATP, and ROS levels, v) a strong inhibition of SIRT2 activity in vitro. NAM significantly delayed tumor growth in vivo (p ≤ 0.0005) and improved survival of melanoma-bearing mice (p ≤ 0.0001). About 3-fold increase (p ≤ 0.05) of Interferon-gamma (IFN-γ) producing cells was observed in NAM treated mice. The plasmatic expression levels of 6 cytokines (namely: Interleukin 5 (IL-5), Eotaxin, Interleukin 12 (p40) (IL12(p40)), Interleukin 3 (IL-3), Interleukin 10 (IL-10) and Regulated on Activation Normal T Expressed and Secreted (RANTES) were significantly changed in the blood of NAM treated mice, suggesting a key role of the immune response. The observed inhibitory effect of NAM on SIRT2 enzymatic activity confirmed previous evidence; we show here that SIRT2 expression is significantly increased in melanoma and inversely related to melanoma-patients survival. Finally, we show for the first time that the expression levels of Niacin receptors HCAR2 and HCAR3 is almost abolished in human melanoma samples.

Conclusion

NAM shows a relevant anti-melanoma activity in vitro and in vivo and is a suitable candidate for further clinical investigations.

Treatment of melasma: a review of less commonly used antioxidants

Melasma, a common cause for seeking dermatologic care, is a chronic condition of skin hyperpigmentation. With a poorly understood pathogenesis, and no universal cure, melasma is a challenge for many dermatologists. For decades, there has been investigation into the role of oxidative stress in melasma. In this literature review, we introduce the role of oxidative stress in melasma and discuss the function of various topical and oral antioxidant therapies for patients suffering from melasma. Numerous studies have shown efficacy of various antioxidant therapies for treatment of hyperpigmentation, and in this review, we focus primarily on those with less widespread use. Vitamin E, niacinamide, polypodium leucotomos, pycnogenol, grape seed extract, amino fruit acids, phytic acid, zinc, silymarin, Korean red ginseng powder, plant extracts, and parsley all have well-demonstrated evidence of antioxidant properties, and these substances have been studied in the context of skin hyperpigmentation. Although there is conflicting evidence of their therapeutic efficacy, the use of these naturally occurring substances is promising for patients and medical providers seeking alternative therapeutic options.

Nicotinamide extrudates as novel anti-aging and collagen promoting platform: a comparative cosmeceutical study versus the gel form

The objective of the study was to explore the potential of a novel nicotinamide extrudate as an anti-aging platform compared to the conventional gel. Nicotinamide extrudates were prepared by hot melt extrusion and characterized pharmaceutically for their thermal behavior, mositure uptake, skin adhesion, and deposition in different skin layers. The pharmacological potential of the extrudates was explored in terms of induction of skin amino acids, cellular energy estimation, 8-hydroxy-2-deoxyguanosine content, Nitrate + nitrite content and histological chacaterization of collagen area percent. Results revealed that the extrusion technique managed to amorphize nicotinamide and enhance its skin deposition (46%) compared to the gel form which only showed about 10% deposition, owing to the mucoadhesive nature of the former. Extrudates were also found superior to the gel form as demonstrated by the increased amino acids level (glycine, proline, hydroxyproline), increased cellular energy, decreased oxidative stress and increased collagen formation. Nictotinamide extrudates were proven to be a scalable promising anti-aging platform which are worthy of entering the cosmeceutical market as products.

Arsenic Trioxide, Itraconazole, All-Trans Retinoic Acid and Nicotinamide: A Proof of Concept for Combined Treatments with Hedgehog Inhibitors in Advanced Basal Cell Carcinoma

The treatment of advanced basal cell carcinoma has seen a progressive evolution in recent years following the introduction of Hedgehog pathway inhibitors. However, given the burden of mutations in the tumor microenvironment and lack of knowledge for the follow-up of advanced basal cell carcinoma, we are proposing a possible synergistic therapeutic application. Our aim is to underline the use of arsenic trioxide, itraconazole, all-trans-retinoic acid and nicotinamide as possible adjuvant therapies either in advanced not responding basal cell carcinoma or during follow-up based on Hedgehog pathway. We have analyzed the rational use of these drugs as a pivotal point to block neoplasm progression, modulate epigenetic modification and prevent recurrences.

Field cancerization: Treatment

The goal of field cancerization treatment is to reduce the risk of developing keratinocyte carcinoma. Selecting the appropriate therapy depends on the degree of field cancerization and the number of invasive cutaneous squamous cell carcinomas. Other considerations include treatment efficacy, cost, side effects, and patient preference. Field therapies are preferred because they address clinically visible disease and subclinical atypia. However, lesion-directed therapies are useful for lesions that are more difficult to treat or those where a histologic diagnosis is required. Patients with extensive field cancerization benefit from a combination of field-directed and lesion-directed treatments. The second article in this continuing medical education series provides a framework to guide evidence-based decision making for field cancerization treatment.

Xylan-based hydrogels for potential skin care application

Skin care biomaterials from natural compounds are increasingly needed in recent. We demonstrate a simple strategy to fabricate the dialdehyde xylan (DAX) crosslinked hydrogel with skin care potential. The hydrogel mainly consists of dialdehyde xylan, which is used as crosslinker for gelatin (G). Glycerol (Gly) and nicotinamide (NCA) are introduced here for improving the texture, antibacterial property as well as skin care functionality. The in vitro release results demonstrate that NCA can be released smoothly from the xylan-based gel, whereby the xylan-based fabricated gel can be utilized as an ideal matrix gel in skin care with loading and release function. The antibacterial ability is in the following order: Yeast > Bacillus subtilis > Staphylococcus aureus. The cytocompatibility experiments confirm the excellent viability of the gel. These merits demonstrate the fabricated hydrogel as a potential material in skin care.

s-HBEGF/SIRT1 circuit-dictated crosstalk between vascular endothelial cells and keratinocytes mediates sorafenib-induced hand-foot skin reaction that can be reversed by nicotinamide

Hand-foot skin reaction (HFSR), among the most significant adverse effects of sorafenib, has been limiting the clinical benefits of this frontline drug in treating various malignant tumors. The mechanism underlying such toxicity remains poorly understood, hence the absence of effective intervention strategies. In the present study, we show that vascular endothelial cells are the primary cellular target of sorafenib-induced HFSR wherein soluble heparin-binding epidermal growth factor (s-HBEGF) mediates the crosstalk between vascular endothelial cells and keratinocytes. Mechanistically, s-HBEGF released from vascular endothelial cells activates the epidermal growth factor receptor (EGFR) on keratinocytes and promotes the phosphorylation of c-Jun N-terminal kinase 2 (JNK2), which stabilizes sirtuin 1 (SIRT1), an essential keratinization inducer, and ultimately gives rise to HFSR. The administration of s-HBEGF in vivo could sufficiently induce hyper-keratinization without sorafenib treatment. Furthermore, we report that HBEGF neutralization antibody, Sirt1 knockdown, and a classic SIRT1 inhibitor nicotinamide could all significantly reduce the sorafenib-induced HFSR in the mouse model. It is noteworthy that nicotinic acid, a prodrug of nicotinamide, could substantially reverse the sorafenib-induced HFSR in ten patients in a preliminary clinical study. Collectively, our findings reveal the mechanism of vascular endothelial cell-promoted keratinization in keratinocytes and provide a potentially promising therapeutic strategy for the treatment of sorafenib-induced HFSR.

Evolution of the use of antioxidants in anti-ageing cosmetics

OBJECTIVE

Skin health and beauty are a cornerstone of general well-being in humans. Anti-ageing cosmetics are used to provide a healthy and youthful appearance. Among the different cosmetic actives, antioxidants are incorporated in anti-ageing products due to their beneficial effects in preventing and minimizing the signs of skin ageing. This work aims to understand how anti-ageing formulations changed in the past 7 years regarding pure antioxidants composition.

METHODS

Data were collected from anti-ageing formulations commercialized in main stores and pharmacies in the Portuguese market. The study started on 2011 and was updated with products launched or whose composition has been renewed on 2013, 2015 or 2018.

RESULTS

Ascorbic acid and tocopherol and their derivatives were consistently the most used antioxidants in anti-ageing formulations; followed by niacinamide and retinyl palmitate. Seven ascorbic acid derivatives are currently used in anti-ageing formulations while only three tocopherol derivatives were identified in this study. Several combinations of antioxidants were routinely found, mainly tocopherol (or tocopherol derivatives) with other antioxidants and tocopherol with tocopherol derivatives. We have not identified emerging antioxidants with great impact in anti-ageing formulations even though niacinamide and retinyl palmitate exhibited over 10% more usage in 2018.

CONCLUSION

This insight is relevant to the cosmetic industry providing a better understanding of the scientific-based formulation of modern cosmetics and supports the need for innovative antioxidants in anti-ageing cosmetics.

Development of an emulgel for the treatment of rosacea using quality by design approach

Objective: The aim of this study was to develop an emulgel for the treatment of rosacea, applying quality by design (QbD).Methods: An emulgel designed to release the active pharmaceutical ingredients (APIs), metronidazole and niacinamide, via an emollient formulation that favors residence time and attenuates facial redness would be an excellent vehicle to develop to treat rosacea. It was decided to design first a vehicle presenting the attributes established in the quality target product profile, and then, after selecting the best formulation, to load the APIs in it to optimize the final emulgel. A design of experiments was introduced to study the effect of formulation variables on quality attributes (adhesion, phase separation by mechanical stress and viscosity) of the emulgels. Response surface methodology and desirability functions were applied for data analysis. After optimization, the final emulgel was further characterized by assay and in vitro release of APIs, attenuation of facial redness, and compared to commercially available metronidazole products regarding API release.Results: The final emulgel gradually released both APIs, reaching approximately 88% within the first 4 h, and their profiles were well described by the Higuchi model. Only a light attenuation effect to conceal facial redness was achieved.Conclusions: A metronidazole and niacinamide emulgel, also providing cosmetic assistance, was developed using QbD. The emulgel releases metronidazole faster than the creams, but more gradually than the commercially available gel, providing a realistic time frame of drug delivery in accordance with the expected time of residence of the adhesive emulgel over the affected facial area.

Extra-mitochondrial citrate synthase initiates calcium oscillation and suppresses age-dependent sperm dysfunction

Men and women become infertile with age, but the mechanism of declining male fertility, more specifically, the decrease in in sperm quality, is not well known. Citrate synthase (CS) is a core enzyme of the mitochondrial tricarboxylic acid (TCA) cycle, which directly controls cellular function. Extra-mitochondrial CS (eCS) is produced and abundant in the sperm head; however, its role in male fertility is unknown. We investigated the role of eCS in male fertility by producing eCs-deficient (eCs-KO) mice. The initiation of the first spike of Ca²⁺ oscillation was substantially delayed in egg fused with eCs-KO sperm, despite normal expression of sperm factor phospholipase C zeta 1. The eCs-KO male mice were initially fertile, but the fertility dropped with age. Metabolomic analysis of aged sperm revealed that the loss of eCS enhances TCA cycle in the mitochondria with age, presumably leading to depletion of extra-mitochondrial citrate. The data suggest that eCS suppresses age-dependent male infertility, providing insights into the decline of male fertility with age.

The protective effects of β-sitosterol and vermicularin from Thamnolia vermicularis (Sw.) Ach. against skin aging in vitro

Aged skin, featured with dryness and wrinkles, has received mounting attention due to its adverse influences on beauty. β-Sitosterol and vermicularin are two common active ingredients of Thamnolia vermicularis (Sw.) Ach., a traditional Chinese medicine, of which the anti-aging effect has been discovered. Their protective performance against skin aging was assayed by co-culturing with skin cells in this work. Results showed that β-sitosterol promoted the biosynthesis of hyaluronic acid by increasing the expression of hyaluronic acid synthases in fibroblasts and enhanced the expression of skin barrier functional proteins including aquaporin 3, loricrin, filaggrin and involucrin in keratinocytes, which conduced to the moisture retention within skin. Moreover, vermicularin might function as an anti-wrinkle agent by preventing the loss of collagen type I. Specifically, vermicularin reduced the amount of reactive oxygen species within hydrogen-peroxide-induced fibroblasts; together with suppressing the activation of mitogen-activated protein kinases, it could inhibit the production of matrix metalloproteinases-1. The present research will contribute to the development of the compounds as anti-aging ingredients for future applications in cosmetic formulations and functional food as well as promote further studies of raw materials containing alike compounds.

Role of Nicotinamide in Genomic Stability and Skin Cancer Chemoprevention

Nicotinamide (NAM) is an amide form of vitamin B3 and the precursor of nicotinamide adenine dinucleotide (NAD+), an essential co-enzyme of redox reactions for adenosine triphosphate (ATP) production and for other metabolic processes. As NAD+ status is critical in maintaining cellular energy, vitamin B3 deficiency mainly affects tissues that need high cellular energy causing pellagra and skin sun sensitivity. In animal models, NAD+ deficiency leads to UV sensitivity of the skin, impairs DNA damage response, and increases genomic instability and cancer incidence. Furthermore, NAD+ depletion is associated with human skin aging and cancer. NAM prevents the UV-induced ATP depletion boosting cellular energy and enhances DNA repair activity in vitro and in vivo. Moreover, NAM reduces skin cancer incidence and prevents the immune-suppressive effects of UV in mice. Thus, NAM is involved in the maintenance of genomic stability and may have beneficial effects against skin aging changes and tumor development. Clinical studies showed that topical use of NAM reduces cutaneous aging. Furthermore, oral NAM administration reduces the level of UV-mediated immunosuppression and lowers the rate of non-melanoma skin cancers in high-risk patients. Therefore, NAM replenishment strategy may be a promising approach for skin cancer chemoprevention.

Steroid-sparing effects and acceptability of a new skin gel containing the anti-inflammatory medicinal substance-nicotinamide

Background/aim: Adex gel (DENI) is a leave-on emollient, containing an ancillary anti-inflammatory medicinal substance, nicotinamide, for use in the treatment and management of dry skin conditions prone to inflammation. The aim of the study was to obtain patients’ and a Medical Investigator’s feedback on the clinical performance and acceptability of the product, and to assess the product’s potential for reducing patients’ reliance on topical corticosteroids and immunomodulators.

Methods: Forty-eight patients were enrolled with 43 patients completing the study. These patients used the product on its own, or as adjunctive therapy, for two weeks instead of their usual emollient, applying it three times daily or more often if necessary. Using a questionnaire, subjects then indicated whether they were in agreement or not with various statements about the clinical performance and acceptability of the product. In the second part of the study, twenty patients used the product for four weeks, this time using it as often as they liked. The Medical Investigator looked at both the performance and the acceptability of the treatment. Patients completed a questionnaire again to indicate how they used it and whether their use of topical corticosteroids and/or immunomodulator treatments had changed.

Results: Patient’s responses were very positive, ranging from 81% to 100% agreement with each performance statement in relation to beneficial effects on the skin. The Medical Investigator considered that for nearly all patients, DENI gel was a helpful and convenient addition to their treatment regime. When questioned on steroid-sparing effects, more than half reported that they needed to use less of their other anti-inflammatory treatments, and nearly 95% reported that they felt their skin condition had benefited from using DENI gel.

Conclusion: This new anti-inflammatory emollient appears to be a helpful addition to the treatment armamentarium for eczema and psoriasis that may reduce reliance on topical corticosteroids and immunomodulators.

Effect of Nicotinamide Against Candida albicans

Nicotinamide (NAM) has a long history in clinical applications and can be safely used for treating various diseases. In recent years, NAM was found to exhibit antimicrobial activities, inhibiting the growth of Plasmodium falciparum, Mycobacterium tuberculosis, and human immunodeficiency virus (HIV). Here we investigated the activity of NAM against Candida albicans, one of the most prevalent human fungal pathogens. Our results showed that NAM exhibited significant antifungal activity against C. albicans, including fluconazole-resistant isolates. NAM could also effectively suppress biofilm formation. In addition, NAM exhibited antifungal activity against non-Candida albicans species and Cryptococcus neoformans. Combination of NAM and fluconazole showed an even strong antifungal activity. The antifungal activity of NAM was further confirmed in a mouse model of disseminated candidiasis. Confocal laser scanning microscopy revealed that NAM increased cell wall β-glucans exposure and chitin content while decreased mannan level. Furthermore, by screening the C. albicans homozygous deletion mutant library, the C. albicans mutant lacking GIN4, which encodes a septin regulatory protein kinase and is essential for the maintenance of cell wall integrity, was identified to be high sensitive to NAM. These findings suggested that NAM might exhibit antifungal activities through affecting cell wall organization.

A Novel Peptide, Nicotinyl⁻Isoleucine⁻Valine⁻Histidine (NA⁻IVH), Promotes Antioxidant Gene Expression and Wound Healing in HaCaT Cells

Nicotinamide (NA), a water-soluble vitamin B₃, has been shown to exert cellular-protective effects against reactive oxygen species (ROS). In order to improve the cellular-protective effects of NA, we synthesized a novel compound, nicotinyl–isoleucine–valine–histidine (NA–IVH), by combining NA with jellyfish peptides’ IVH. In the present study, we examined the cellular-protective effects of the novel synthetic nicotinyl-peptide, NA–IVH. We found that NA–IVH enhances the radical scavenging activity with a robust increase of the nuclear factor (erythroid-derived 2)-like factor (Nrf2) expression in human HaCaT keratinocytes. In addition, NA–IVH protected the cells from hydrogen peroxide (H₂O₂)-induced cell death. Interestingly, NA–IVH exhibited an improved wound-healing effect in a high glucose condition, possibly through the regulation of reactive oxygen species (ROS). Collectively, our results imply that a novel nicotinyl-peptide, NA–IVH, has a wound-healing effect in a hyperglycemic condition, possibly by modulating excessive ROS.

Skin cancer management-updates on Merkel cell carcinoma

There are many different types of skin tumors in the World Health Organization (WHO) classification. The natural course and treatment varies according to the histological type. This review summarizes clinical experience for treatment decision. Contemporary radiotherapy and systemic therapy are improving. Landmark studies for basal cell and Merkel cell carcinomas (MCC) trigger further research and impetus for improving treatment outcome. Avelumab, nivolumab, pembrolizumab, ipilimumab appear to be promising for treatment of advanced MCCs and adjuvant trials are underway.

Therapeutic Potential of NAD-Boosting Molecules: The In Vivo Evidence

Nicotinamide adenine dinucleotide (NAD), the cell's hydrogen carrier for redox enzymes, is well known for its role in redox reactions. More recently, it has emerged as a signaling molecule. By modulating NAD⁺-sensing enzymes, NAD⁺ controls hundreds of key processes from energy metabolism to cell survival, rising and falling depending on food intake, exercise, and the time of day. NAD⁺ levels steadily decline with age, resulting in altered metabolism and increased disease susceptibility. Restoration of NAD⁺ levels in old or diseased animals can promote health and extend lifespan, prompting a search for safe and efficacious NAD-boosting molecules that hold the promise of increasing the body's resilience, not just to one disease, but to many, thereby extending healthy human lifespan.

Tacrolimus nanoparticles based on chitosan combined with nicotinamide: enhancing percutaneous delivery and treatment efficacy for atopic dermatitis and reducing dose

Background

Topical application of tacrolimus (FK506) was effective in the treatment of atopic dermatitis (AD); however, adverse effects frequently occurred with the increase of FK506 dose during long–term treatment.

Objective

The objective of this project was to develop a hybrid skin targeting system encapsulating FK506 based on nicotinamide (NIC) and chitosan nanoparticles (CS–NPs), ie, FK506–NIC–CS–NPs, which took advantages of both of NIC and CS–NPs to obtain the synergetic effects of percutaneous delivery and treatment efficacy enhancement along with dose reduction.

Methods

The formulation of FK506–NIC–CS–NPs was optimized and characterized. In vitro and in vivo skin permeation studies were performed. AD–like skin lesions were constructed with BALB/c mice by 1–chloro–2, 4–dinitrobenzene (DNCB)–induced, and FK506–NIC–CS–NPs containing different dose of FK506 were topically administered to treat AD–like skin lesions in comparison with Protopic.

Results

NIC was found to significantly increase the FK506 EE to 92.2% by CS–NPs. In comparison with commercial FK506 ointment (Protopic), in vitro and in vivo skin permeation studies demonstrated that NIC–CS–NPs system significantly enhanced FK506 permeation through and into the skin, and deposited more FK506 into the skin. The treatment efficacy on clinical symptoms, histological analysis, and molecular biology of the AD–mice demonstrated that NIC–CS–NPs with ~1/3 dose of FK506 of Protopic was superior to that of Protopic, and NIC–CS–NPs vehicle exhibited the adjuvant therapy and moderate anti–AD effects.

Conclusion

The system of NIC–CS–NPs enhances the permeability of FK506, plays an adjuvant role in anti-AD, reduces the dose of FK506 in treating AD, and is therefore a promising nanoscale system of FK506 for the effective treatment of AD.

Nicotinamide-based diamides derivatives as potential cytotoxic agents: synthesis and biological evaluation

A series of diamides derivatives containing nicotinamide unit were designed, synthesized and evaluated for their potential cytotoxic activities against human cancer cell lines. All the synthesized compounds were characterized using spectroscopic methods mainly including ¹H NMR, ¹³C NMR and MS. The bio-evaluation results indicated that some of the obtained compounds (such as 4d, 4h, 4i) exhibited good to moderate cytotoxic effects on lung cancer cell lines (NCI-H460, A549, and NCI-H1975), especially, compound 4d exhibited the highly potential inhibitory activities against NCI-H460 cell line with the IC₅₀ values of 4.07 ± 1.30 μg/mL, which might be developed as novel lead compounds for potential cytotoxic agents.

In vitro permeation and disposition of niacinamide in silicone and porcine skin of skin barrier-mimetic formulations

Niacinamide (NIA) is an amide form of vitamin B3 which is used in cosmetic formulations to improve various skin conditions and it has also been shown to increase stratum corneum thickness following repeated application. In this study, three doses (5, 20 and 50μL per cm²) of two NIA containing oil-in-water skin barrier-mimetic formulations were evaluated in silicone membrane and porcine ear skin and compared with a commercial control formulation. Permeation studies were conducted over 24h in Franz cells and at the end of the experiment membranes were washed and niacinamide was extracted. For the three doses, retention or deposition of NIA was generally higher in porcine skin compared with silicone membrane, consistent with the hydrophilic nature of the active. Despite the control containing a higher amount of active, comparable amounts of NIA were deposited in skin for all formulations for all doses; total skin absorption values (permeation and retention) of NIA were also comparable across all formulations. For infinite (50μL) and finite (5μL) doses the absolute permeation of NIA from the control formulation was significantly higher in porcine skin compared with both test formulations. This likely reflects differences in formulation components and/or presence of skin penetration enhancers in the formulations. Higher permeation for the 50 and 20μL dose was also evident in porcine skin compared with silicone membrane but the opposite is the case for the finite dose. The findings point to the critical importance of dose and occlusion when evaluating topical formulations in vitro and also the likelihood of exaggerated effects of excipients on permeation at infinite and pseudo-finite dose applications.