Cutaneous Effects Research Articles

Formulation and Physicochemical Characterization of Terpenocannabinoid-Functionalized Hemp Oil Emulsifier: Assessment of Topical Anti-Inflammatory, Antinociceptive, Wound Healing Activity and Cutaneous Toxicity Effects

Formulation and Physicochemical Characterization of Terpenocannabinoid-Functionalized Hemp Oil Emulsifier: Assessment of Topical Anti-Inflammatory, Antinociceptive, Wound Healing Activity and Cutaneous Toxicity Effects

Characterization of adverse cutaneous effects in the setting of enfortumab vedotin for metastatic urothelial carcinoma: A retrospective review

Characterization of adverse cutaneous effects in the setting of enfortumab vedotin for metastatic urothelial carcinoma: A retrospective review

Effect of fractional picosecond laser therapy using a diffractive optical lens on histological tissue reaction

ABSTRACT Background and Objectives Fractional ablative resurfacing techniques are preferred treatments for facial rejuvenation of aged skin. This study was performed to investigate the cutaneous effects of using a fractional picosecond laser at 1064 nm with a diffractive lens. Methods The penetration depth according to the location of the handpiece tip was evaluated using an acrylic panel. Laser induced optical breakdown (LIOB) and cutaneous damage were observed after hematoxylin and eosin staining in guinea pigs. Collagen formation was evaluated using Victoria staining, Masson’s trichrome (MT) staining, and immunohistochemical staining for collagen type III. Results The penetration depth for LEVEL 1 was 499.98–935.23 μm (average: 668.75 ± 182.84 μm); the LIOB cavity area was 1664.17 ± 650.52 μm2. The penetration depth of LEVEL 2 was 257.12–287.38 μm (average: 269.77 ± 14.55 μm) with an LIOB cavity area of 1335.85 ± 214.41 μm2. At LEVEL 3, that was 36.17–53.69 μm (average: 52.15 ± 20.81 μm) and the LIOB cavity area was 1312.67 ± 1069.12 μm2. No epidermal tissue damage was observed and collagen formation was observed from day 14 under all conditions. Conclusion Diffractive optical element (DOE) lens arranged laser treatment system controlled the position of LIOB occurrence and an irradiating area.

Synergistic interaction of guanfacine or dexmedetomidine coadministered with lidocaine for cutaneous analgesia in rats

ABSTRACT Background This study examined the cutaneous analgesic effects of lidocaine co-injected with guanfacine and its comparison with dexmedetomidine. Methods Cutaneous analgesic effects are quantified through the blocking effects of the cutaneous trunci muscle reflex against skin pinpricks in rats. The dose-response curves of guanfacine, dexmedetomidine, and lidocaine were constructed and drug-drug interactions were analyzed by the ED50 isobologram. Results Subcutaneous injections of guanfacine, dexmedetomidine, and lidocaine produced dose-dependently nociceptive/sensory blockade. On the ED50 (50% effective dose) basis, the potency rankings of the drug are dexmedetomidine (0.09 [0.08–0.11] μmol/kg) > guanfacine (3.98 [2.96–5.34] μmol/kg) > lidocaine (25.40 [23.51–27.44] μmol/kg) (p < 0.01). On their equipotent doses (ED25, ED50, and ED75), the duration of sensory blockade induced by guanfacine or dexmedetomidine was longer than lidocaine’s (p < 0.01). Both guanfacine and dexmedetomidine showed synergistic effects with lidocaine. Conclusions We showed that guanfacine elicits dose-dependent cutaneous analgesia when administered subcutaneously. Lidocaine is less potent than guanfacine or dexmedetomidine. Both guanfacine and dexmedetomidine enhance the potency and duration of lidocaine. Better synergistic responses we are getting with guanfacine plus lidocaine.

Blue light impairs the repair of UVB-induced pyrimidine dimers in a human skin model.

In recent years, interest is growing in the biological cutaneous effects of high-energy visible light (400-450 nm). In the present study, we explored the impact of blue light (BL) on the repair of pyrimidine dimers, the major class of premutagenic DNA damage induced by exposure to sunlight. We unambiguously demonstrate that the exposure of invitro reconstructed human epidermis to environmentally relevant doses of BL strongly decreases the rate of repair of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts induced by a subsequent UVB irradiation. Using the highly sensitive and specific liquid chromatography-tandem mass spectrometry assay, we did not observe induction of pyrimidine dimers by BL alone. Finally, we showed that application, during the BL exposure step, of a formula containing a new filter, named TriAsorB and affording BL photoprotection, prevented the decrease in DNA repair efficiency. These results emphasize the potential deleterious effects of BL on DNA repair and the interest in providing adequate skin protection against this wavelength range of sunlight.

Assessment of Occupational Risks Associated with Chemical Reagents in the Hemobiology Laboratory of an Eastern Algerian University Hospital Center

The variety and diversity of chemicals handled in hospital laboratories make it imperative to conduct periodic risk assessments for enhanced protection of medical personnel and the implementation of an appropriate prevention policy. It is within this context that our study was conducted in the hemobiology laboratories of an eastern Algerian university hospital center. We employed a semi-quantitative assessment method tailored to the specificities of hospitals. An inventory of chemical agents was conducted using data collection sheets detailing the product names, quantities, and frequencies of use. Relying on information from the Safety Data Sheet (SDS) and associated pictograms.We characterized the hazards posed by these chemicals and prioritized their associated risks. The hemobiology laboratory staff use 49 chemical reagents, with 28% of them considered hazardous, demanding appropriate safety precautions. The study highlighted the significance of systemic and local cutaneous effects, such as sensitivity (94.6%). Ocular risk, with severe injuries, was caused by 33.3% of the reagents. Seventeen reagents could lead to respiratory systemic effects. Ten reagents posed a carcinogenic, mutagenic, and reprotoxic (CMR) risk, such as Chloroform, Formaldehyde, ADVIA Perox 1, ADVIA Perox 2, ADVIA Perox 3. This evaluation has highlighted the multiple health risks faced by the personnel in the hemobiology laboratory. It is imperative to establish a comprehensive strategy for managing occupational risks to ensure the long-term protection of the workers.

The Importance of Photoaging Prevention in All Skin Types: An Update on Current Advancements.

Light from across the electromagnetic spectrum, including ultraviolet, visible, and infrared light, can cause detrimental cutaneous effects including photocarcinogenesis and photoaging. Traditional and broad-spectrum sunscreens offer protection against ultraviolet radiation. However, visible and infrared light may not always be covered by traditional sunscreens. These forms of solar radiation have been shown to cause photodamage and may have particular importance in the effects induced in skin of color. This article aims to review the mechanisms of photoaging from various light forms, the implications of these damaging effects on skin of color, and innovative approaches that can advance the way patients practice photoprotection. We will expand upon the latest innovations in photoprotection that hold the potential to increase patient adherence and improve skin health across all skin types. J Drugs Dermatol. 2024;23(1):1306-1310. &nbsp; doi:10.36849/JDD.7255.

Tension as a key factor in skin responses to pollution

Being the more apparent organ exposed to the outdoor stressors, the effect of pollution on the skin has been widely studied in the last few decades. Although UV light is known as the most aggressive stressor to which our cutaneous tissue is daily exposed, other components of the tropospheric pollution have also shown to affect skin health and functionality. Among them, ozone has been proven to be one of the most toxic due to its high reactivity with the epidermal lipids. Studying the cutaneous effect of pollution in a laboratory setting presents challenges, therefore it becomes critical to employ appropriate and tailored models that aim to answer specific questions. Several skin models are available nowadays: in vitro models (2D cell lines and 3D cutaneous tissues), ex vivo skin explants and in vivo approaches (animals and humans). Although in the last 20 years researchers developed skin models that closely resemble human skin (3D cutaneous tissues), ex vivo skin explants still remain one of the best models to study cutaneous responses. Unfortunately, one important cutaneous property that is not present in the traditional ex vivo human skin explants is the physiological tension, which has been shown to be a cardinal player in skin structure, homeostasis, functional properties and responses to external stimuli. For this reason, in this study, to confirm and further comprehend the harmful mechanism of ozone exposure on the integumentary system, we have performed experiments using the state of art in cutaneous models: the innovative TenSkin™ model in which ex vivo human skin explants are cultured under physiologically relevant tension during the whole experimental procedure. Specifically, we were interested in corroborating previous findings showing that ozone exposure modulates the expression of cutaneous antimicrobial peptides (AMPs). The present work demonstrates that cutaneous exposure to ozone induces AMPs gene and protein levels (CAMP/LL-37, hBD2, hBD3) and that the presence of tension can further modulate their expression. In addition, different responses between tension and non-tension cultured skin were also observed during the evaluation of OxInflammatory markers [cyclooxygenase-2 (COX2), aryl hydrocarbon receptor (AhR), matrix-metallo-proteinase 9 (MMP9) and 4-hydroxy-nonenal (4HNE)]. This current study supports our previous findings confirming the ability of pollution to induce the cutaneous expression of AMPs via redox signaling and corroborates the principle that skin explants are a good and reliable model to study skin responses even though it underlines the need to holistically consider the role of skin tension before extrapolating the data to real life.

Assessment of the Effects of Quince Seed Mucilage and Wheat Germ Oil on Wound Healing in Rats

Objective: People have used traditional herbal medicines for wound care since the dawn of time. This study aimed to assess the cutaneous wound healing effects of wheat germ oil (WGO) and quince seed mucilage (QSM) in rats.&#x0D; Methods: Adult female Wistar albino rats were allocated to one of the three groups: rats treated with topical WGO (n=6); topical QSM (n=6); and topical saline (n=6) as the control group. Two circular, full-thickness wounds of 0.6 mm diameter were created on the dorsal thoracic region of each rat. Test and control solutions were applied twice daily for 14 days. Wound healing was assessed by measuring the wound contraction rate and the time needed for complete epithelialization.&#x0D; Results: When compared with the control group, rats in the WGO group had reduced wound closure rates in the first four days, but considerably greater rates in the 8th, 10th, and 12th days, as well as a shorter duration of time needed to complete epithelialization (11 days vs. 13 days). The wound closure rates of the rats in the QSM group were not substantially different from the control rats and the duration of time needed for complete epithelialization was not significantly different from the control group. &#x0D; Conclusion: WGO use has been shown to improve wound healing. It may be used as an alternative or complementary approach for wound treatment depending on the severity of the wounds. On the other hand, QSM was not found to improve wound healing.

Broad-spectrum sunscreens containing the TriAsorB™ filter: In vitro photoprotection and clinical evaluation of blue light-induced skin pigmentation.

Blue light (BL), particularly high-energy visible (HEV) light (400-450 nm), can cause skin damage and pigmentation. Therefore, effective sunscreens should offer photoprotection beyond ultraviolet (UV) radiation to also prevent or limit BL-induced cutaneous effects. To evaluate the in vitro BL photostability and photoprotection properties of nine sunscreens containing the broad-spectrum UV/BL phenylene bis-diphenyltriazine (PBDT or TriAsorB™) filter, together with three other organic UV filters, and to assess the in vivo photoprotection level provided by two of these products against BL-induced skin pigmentation. In vitro BL photostability and photoprotection factors, comprising the percentage of BL radiation stopped by the product (%BL) and the critical wavelength extended to BL (BL-CW), were determined by spectrophotometry. The in vivo photoprotection provided by two representative sunscreens (i.e. similar formulations, one non-tinted and one tinted) was assessed in two open randomized studies (20 and 16 women, respectively) after exposure of two test areas (with and without sunscreen) on the back of each subject to a 412-nm irradiation dose at 50 J/cm2 , using instrumental and clinical measurements of skin pigmentation. The percentage sunscreen photoprotective effectiveness (%PPE) was calculated by comparing intrasubject post-exposure pigmentation changes between the with and without sunscreen test areas. In vitro, the nine PBDT-containing products were highly photostable and had a BL-CW ≥385 nm and a %BL ≥30% (range: 30%-50%), thus allowing effective BL photoprotection. In vivo, both representative sunscreens prevented BL-induced immediate skin pigmentation (1 and 24 h post-exposure) with %PPE values ranging from 50.7% to 75.5% for colorimetric assessments (p < 0.001) and from 31.2% to 72.7% for visual scores (p ≤ 0.001). All PBDT-containing sunscreens were considered effective at absorbing BL radiation in vitro. The two representative broad-spectrum sunscreens tested in subjects significantly reduced BL-induced immediate skin pigmentation following single exposure to monochromatic BL radiation.

44373 Characterizing the Cutaneous Late Effects of Haematopoietic Stem Cell Transplantation: A Systematic Review.

44373 Characterizing the Cutaneous Late Effects of Haematopoietic Stem Cell Transplantation: A Systematic Review.

43994 Cutaneous Effects of Sunscreen with Adjuvant DNA Repair Moisturizer

43994 Cutaneous Effects of Sunscreen with Adjuvant DNA Repair Moisturizer

COMPLICATIONS OF MONKEYPOX

Introduction: Monkeypox is a rare, viral and emerging disease, although in recent months it has become a growing concern for health professionals and public health authorities around the world. The disease is caused by an orthopoxvirus of the same genus as the human smallpox virus and can cause serious complications in both humans and animals. Objective: To show, through the scientific literature, the complications of monkeypox. Methodology: This is an integrative literature review research, carried out between the months of May and July 2023, through a survey of data in the scientific bases of health: LILACS and SCIELO. Results and Discussion: Through the analysis of the selected studies, the main information for the discussion of this study was evaluated. Scientific evidence has shown that monkeypox complications can vary according to the severity of the patient and can affect different systems of the human body. The scientific literature has pointed out that the main complications of monkeypox include skin infections and skin abscesses. In addition, infection with the virus can provoke the development of cardiac complications, such as myocarditis and heart failure. It can cause abnormal heart rhythms and other cardiovascular problems. Monkeypox develops more severely in people with weakened immune systems because the body has difficulty controlling viral replication. In such cases, the infection can spread quickly and affect various organs and systems in the body. Conclusion: Complications of monkeypox pose significant public health and safety challenges. Although the disease is less lethal than smallpox in humans, it can cause serious complications in infected patients, with localized cutaneous effects such as pustule formation and secondary infections, as well as systemic effects affecting vital organs and body systems.

CPC02 Delayed widespread lichenoid drug reaction with radioisotopic response in a patient treated with nivolumab

Abstract The introduction of immune checkpoint inhibitors for the treatment of a wide variety of malignancies has led to a rise in cutaneous immune-related adverse events (irAEs), including autoimmune and autoinflammatory skin conditions, which typically present within the first 16 weeks of treatment—on average, 3.6 weeks after drug initiation. Cutaneous irAEs occur in approximately 8.7% of patients receiving antiprogrammed cell death type 1 therapy (PD-1). Nivolumab is an antibody against PD-1 widely used for various cancers. As the application of these therapies expands, understanding of their adverse cutaneous effects is essential. We present a 76-year-old woman with metastatic renal cell carcinoma, who developed a widespread pruritic eruption 18 months after commencing nivolumab. Examination revealed a papular and vesicular rash affecting the arms, legs, anterior chest, face, hands and feet. There was a confluent well-demarcated rectangular area of grouped papules on the right side of her back; this site had been treated with radiotherapy for localized rib metastases 1 month prior to onset of rash. There was no mucosal involvement and no systemic symptoms. Three skin biopsies were taken, which showed vacuolar alteration of the basal layer and a band-like inflammatory cell infiltrate at the dermoepidermal junction, with focal areas of subepidermal separation. Direct immunofluorescence was negative, and skin swabs were negative for bacterial and viral infection. A diagnosis of delayed bullous lichenoid drug reaction secondary to nivolumab was made. The area involving the previous radiotherapy field was considered to be a radioisotopic response rather than a radiation recall response as she was already on nivolumab when it occurred. She discontinued nivolumab and commenced oral prednisolone and her skin settled over 5 weeks. Lichenoid dermatitis is a known adverse reaction associated with PD-1 therapy, with improved survival outcomes noted in patients with lichenoid irAEs on PD-1 therapy. Typically, it occurs within 16 weeks, with a documented range of 1–266 days. This patient developed a delayed lichenoid eruption at approximately 550 days, with concurrent radioisotopic response at a previous radiotherapy site. Radiotherapy-induced lichen planus is rare, with only one case report documenting involvement outside the irradiated field. We found no previous reports of nivolumab causing lichenoid drug eruption after such a protracted period. This case adds to the growing literature around PD-1 inhibitor-associated cutaneous eruptions.

BI24 Cutaneous pseudolymphoma secondary to pembrolizumab

Abstract A 35-year-old man presented with a 7-week history of itchy, nontender, indurated erythematous plaques and nodules on his forehead and upper back, with no discriminatory clinical features. He was systemically well. Three months previously, he had completed a 12-month course of adjuvant pembrolizumab for stage IIIC melanoma. The primary melanoma had been excised from his left cheek, with involvement of left parotid and supraclavicular lymph nodes, treated with clearance via superficial parotidectomy and left neck dissection. Clinical and imaging surveillance revealed no evidence of melanoma recurrence. Incisional biopsies of the lesions on his back and forehead both demonstrated a superficial and deep dermal perivascular and periadnexal infiltrate of small- and medium-sized lymphoid cells. There was no epidermotropism and B- and T-cell clonality studies were negative. Morphological appearance and immunophenotype favoured a CD4+-reactive lymphoid process in keeping with cutaneous pseudolymphoma (CPL), secondary to pembrolizumab. The conspicuous forehead lesion was unresponsive to clobetasol propionate under occlusion. A single course of intralesional triamcinolone acetonide 10 mg mL–1 resulted in significant improvement within days, with subsequent complete resolution. The lesion on the back resolved spontaneously. Drug-induced CPL describes an adverse cutaneous drug reaction mimicking B- or T-cell lymphomas clinically and/or histologically. It has been described with anticonvulsants, antidepressants and biologic agents, often with resolution on cessation of the responsible drug (Etesami I, Kalantari Y, Tavakolpour S et al. Drug-induced cutaneous pseudolymphoma: a systematic review of the literature. Australas J Dermatol 2023; 64:41–9). It has been proposed that the drugs affect immune surveillance, leading to an abnormal cutaneous lymphocyte response. A case report (Ayoubi N, Haque A, Vera N et al. Ipilimumab/nivolumab-induced pseudolymphoma in a patient with malignant melanoma. J Cutan Pathol 2020; 47:390–3) has described drug-induced CPL secondary to ipilimumab and nivolumab in a 38-year-old man presenting with erythematous plaques on the hands and face, similar to the presentation of our patient, which responded to prednisolone. As with the other adverse effects of immunotherapy, it is likely that CPL in this cohort is due to an iatrogenic immune dysregulation leading to T-cell overactivity. We present the first reported case of CPL secondary to pembrolizumab and highlight the successful use of intralesional steroid as a treatment option. It is important to recognize CPL as an adverse cutaneous effect of immunotherapy and be aware that it can present after completing treatment due to an ongoing immune response.

A comparative study on the effect of dopamine vs phenylephrine in improving the cutaneous analgesic effect of mexiletine in rats

BackgroundThe present study aimed to compare the effects of the combined administration of two adjuvants, dopamine and phenylephrine, on the cutaneous analgesic effect and duration of mexiletine in rats.MethodsNociceptive blockage was evaluated by the inhibition of response to skin pinpricks in rats via the cutaneous trunci muscle reflex (CTMR). After subcutaneous injection, the analgesic activities of mexiletine in the absence and presence of either dopamine or phenylephrine were assessed. Each injection was standardized into 0.6 ml with a mixture of drugs and saline.ResultsSubcutaneous injections of mexiletine successfully induced dose-dependent cutaneous analgesia in rats. The results revealed that rats injected with 1.8 μmol mexiletine exhibited 43.75% blockage (%MPE), while rats injected with 6.0 μmol mexiletine showed 100% blockage. Co-application of mexiletine (1.8 or 6.0 μmol) with dopamine (0.06, 0.60, or 6.00 μmol) elicited full sensory block (%MPE). Sensory blockage ranged from 81.25% to 95.83% in rats injected with mexiletine (1.8 μmol) and phenylephrine (0.0059 or 0.0295 μmol), and complete subcutaneous analgesia was observed in rats injected with mexiletine (1.8 μmol) and a higher concentration of phenylephrine (0.1473 μmol). Furthermore, mexiletine at 6.0 μmol completely blocked nociception when combined with any concentration of phenylephrine, while 0.1473 μmol phenylephrine alone exhibited 35.417% subcutaneous analgesia. The combined application of dopamine (0.06/0.6/6 μmol) and mexiletine (1.8/6 μmol) resulted in increased %MPE, complete block time, full recovery time, and AUCs compared to the combined application of phenylephrine (0.0059 and 0.1473 μmol) and mexiletine (1.8/6 μmol) (p < 0.001).ConclusionDopamine is superior to phenylephrine in improving sensory blockage and enhancing the duration of nociceptive blockage by mexiletine.

Protective effect and mechanism research of Phyllanthus emblica Linn. fruit extract on UV-induced photodamage in keratinocytes.

Ultraviolet (UV) irradiation causes acute and chronic cutaneous effects that may result in photodamage and photoaging. Epidermis keratinocytes, as the closest surface of skin, are susceptible to damage from UV rays. Phyllanthus emblica Linn. fruit (PE) extract, as a medicine and food dual-use plant, contains high levels of polyphenols and possesses multiple pharmacological properties. The present study investigated common and different molecular mechanisms and signaling pathway activations of UVA and UVB stimulated cell damage and photoprotective effect of PE extract against UVA and UVB by Methyl Thiazolyl Tetrazolium (MTT) method, Elisa assay, flow cytometry, differentially expressed genes analysis and western blot analysis. The results showed that UVA exposure (10J/cm2) reduced HaCaT cell viability significantly, increased the apoptosis rate, elevated intracellular reactive oxygen species level and reduced antioxidant enzyme activities. And UVA irradiation could inhibit the ERK/TGF-β/Smad signaling pathway to downregulate collagen I, collagen III and elastin expressions, resulting in the photoaging of skin cells. We also found UVB exposure (30mJ/cm2) caused HaCaT cell damage, promoted apoptosis, increased ROS production and induced the release of proinflammatory cytokines (IL-1α, IL-6 and PGE2). Further, in HaCaT cells, UVB ray was able to induce the activation of apoptosis markers (cleaved PARP1 and cleaved caspase3) through the MAPK/AP-1 signaling pathway using western blot analysis. Pre-treatment of PE extract prevented the UVA and UVB induced photoaging and injury in HaCaT cells through activation of ERK/TGF-β/Smad pathway and inhibition of MAPK/AP-1 pathway, respectively. Therefore, PE extract has the potential to be used as an oral and topical preparation against skin aging and injury induced by UVA and UVB.

Skin Diseases Associated With COVID-19: A Narrative Review.

COVID-19 is an infectious disease caused by SARS-CoV-2, which emerged in China in 2019 and rapidly spread worldwide to become a pandemic in March 2020. Although the most severe manifestations concern the lower respiratory tract, COVID-19 is a multiorgan disease that also affects the skin. Several types of skin lesions have been reported to be associated with SARS-CoV-2 infection, though their causal relationship with the virus has not yet been well documented. In addition to the cutaneous manifestations that develop in patients with COVID-19-thought to be caused by the virus-other findings associated with the pandemic in a broader sense include dermatoses triggered or aggravated by the infection, the adverse cutaneous effects due to the drugs and protective devices used to prevent or fight the infection, and the adverse cutaneous effects of COVID-19 vaccines. We provide an overview of these dermatoses associated with the COVID-19 pandemic.

Water Is an Active Element: A Randomized Double-Blind Controlled Clinical Trial Comparing Cutaneous Lipidomics in Consumers Drinking Two Different Bicarbonate-Calcic Waters (Medium-Mineral vs. Oligo-Mineral).

Despite the well-known cutaneous beneficial effect of thermal water on the skin, no data exist regarding the potential biological effect of orally consumed water on healthy skin. Thus, in this single-center, double-blind, randomized controlled clinical trial conducted on age and menstrual cycle timing-matched healthy female volunteers (24 + 24) consuming water A (oligo-mineral) or water B (medium-mineral) for 1 month (T1), the cutaneous lipidomics were compared. Interestingly, only water A consumers had a statistically significant (p < 0.001) change in cutaneous lipidomics, with 66 lipids different (8 decreased and 58 increased). The cutaneous lipidomics of consumers of water A vs. water B were statistically different (p < 0.05). Twenty cutaneous lipids were necessary to predict the water type previously consumed (AUC ~70). Our study suggests that drinking oligo-mineral water may change skin biology and may influence the cutaneous barrier, so future dermatological clinical trials should also account for the water type consumed to avoid potential confounders.

Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients

BackgroundImmunosuppressed organ-transplant recipients have an increased incidence of, and mortality from, skin cancer. Nicotinamide (vitamin B3) enhances the repair of ultraviolet (UV) radiation–induced DNA damage, reduces the cutaneous immunosuppressive effects of UV radiation, and reduces the incidence of keratinocyte cancers (including squamous-cell and basal-cell carcinomas) and actinic keratoses among high-risk immunocompetent patients. Whether oral nicotinamide is useful for skin-cancer chemoprevention in organ-transplant recipients is unclear.MethodsIn this phase 3 trial, we randomly assigned, in a 1:1 ratio, organ-transplant recipients who had had at least two keratinocyte cancers in the past 5 years to receive 500 mg of nicotinamide or placebo twice daily for 12 months. Participants were examined for skin lesions by dermatologists at 3-month intervals for 12 months. The primary end point was the number of new keratinocyte cancers during the 12-month intervention period. Secondary end points included the numbers of squamous-cell and basal-cell carcinomas during the 12-month intervention period, the number of actinic keratoses until 6 months after randomization, safety, and quality of life.ResultsA total of 158 participants were enrolled, with 79 assigned to the nicotinamide group and 79 to the placebo group. The trial was stopped early owing to poor recruitment. At 12 months, there were 207 new keratinocyte cancers in the nicotinamide group and 210 in the placebo group (rate ratio, 1.0; 95% confidence interval, 0.8 to 1.3; P=0.96). No significant between-group differences in squamous-cell and basal-cell carcinoma counts, actinic keratosis counts, or quality-of-life scores were observed. Adverse events and changes in blood or urine laboratory variables were similar in the two groups.ConclusionsIn this 12-month, placebo-controlled trial, oral nicotinamide therapy did not lead to lower numbers of keratinocyte cancers or actinic keratoses in immunosuppressed solid-organ transplant recipients. (Funded by the National Health and Medical Research Council; ONTRANS Australian New Zealand Clinical Trials Registry number, ACTRN12617000599370.)