Response of mouse skin to tattooing: use of SKH-1 mice as a surrogate model for human tattooing

Biodistribution of iron oxide tattoo pigment: An experimental murine study

Tattoo pigment is expected to migrate beyond the skin to regional lymph nodes and the liver. Modern tattoo ink commonly contains metals that may pose a clinical problem during MRI examinations. This study aimed to investigate the biodistribution of iron oxide pigment to internal organs in mice. Moreover, when exposed to a static magnetic field, we studied whether any reactions followed in the tattooed skin. Twenty-seven hairless C3.Cg-Hrhr/TifBomTac mice were included; 20 were tattooed with iron oxide ink in a rectangular 3 cm2 pattern; seven were controls. Ten of the tattooed mice were exposed to a 3 T MRI scanner's static magnetic field. Following euthanasia, evaluations of dissected organs involved MRI T2*-mapping, light microscopy (LM) and metal analysis. T2*-mapping measures the relaxation times of hydrogen nuclei in water and fat, which may be affected by neighbouring ferrimagnetic particles, thus enabling the detection of iron oxide particles in organs. Elemental analysis detected a significant level of metals in the tattooed skin compared to controls, but no skin reactions occurred when exposed to a 3 T static magnetic field. No disparity was observed in the liver samples with metal analysis. T2* mapping found no significant difference between the two groups. Only minute clusters of pigment particles were observed in the liver by LM. Our results demonstrate a minimal systemic distribution of the iron oxide pigments to the liver, whereas the kidney and brain were unaffected. The static magnetic field did not trigger skin reactions in magnetic tattoos but may induce image artefacts during MRI.

Biotagging method for animal identification using dissolvable microneedle arrays prepared by customisable moulds

Properly handling animals and understanding their habits are crucial to establish a society where humans and animals coexist. Thus, identifying individual animals, including their possessions, and adequately managing each animal is necessary. Although several conventional identification methods exist, such as the use of ear punch, tattoos, and radio frequency (RF) chips, they require several processes and external apparatus. In this study, we proposed a new biotagging method using a microneedle array for animal identification. Our approach uses dissolvable microneedle arrays as a single patch to deliver dyes directly into the skin layer. Additionally, we developed a new fabrication method for customised female moulds to realise microneedle array patches (MAPs) with patterns of different characters and number. The characteristics and feasibility of the patterned MAPs were confirmed through basic evaluations and animal experiments. Moreover, we confirmed that patterns formed from biotagging using the developed patterned MAPs lasted over one month with clear readability. Finally, we confirmed that our patterned MAPs successfully realised biotagging on rat skin with the designated patterns including characters and number patterns. The proposed method is expected to enable minimally invasive tagging without external equipment or complex processes. In addition, the developed method could be used to embed various tags into the skin of animals and humans in the future.

Immunotoxicity of N-butylbenzenesulfonamide: impacts on immune function in adult mice and developmentally exposed rats

N-butylbenzenesulfonamide (NBBS) is a high-production volume plasticizer that is an emerging contaminant of concern for environmental and human health. To understand the risks and health effects of exposure to NBBS, studies were conducted in adult-exposed mice and developmentally exposed rats to evaluate the potential for NBBS to modulate the immune system. Beginning between 8 and 9 weeks of age, dosed feed containing NBBS at concentrations of 0, 313, 625, 1250, 2500, and 5000 ppm was continuously provided to B6C3F1/N female mice for 28 days. Dosed feed was also continuously provided to time-mated Harlan Sprague Dawley (Sprague Dawley SD) rats at concentrations of 0-, 250-, 500-, and 1000-ppm NBBS from gestation day 6 to postnatal day 28 and in F1 rats until 11-14 weeks of age. Functional assessments of innate, humoral, and cell-mediated immunity were conducted in adult female mice and F1 rats following exposure to NBBS. In female mice, NBBS treatment suppressed the antibody-forming cell (AFC) response to SRBC with small increases in T-cell responses and natural killer (NK)-cell activity. In developmentally exposed rats, NBBS treatment-related immune effects were sex dependent. A positive trend in NK-cell activity occurred in male F1 rats while a negative trend occurred in female F1 rats. The AFC response to SRBC was decreased in female F1 rats but not in male F1 rats. These data provide evidence that oral exposure to NBBS has the potential to produce immunomodulatory effects on both innate and adaptive immune responses, and these effects appear to have some dependence on species, sex, and period of exposure (developmental vs adult).

Low doses of 3-phenyl-lawsone or meglumine antimoniate delivery by tattooing route are successful in reducing parasite load in cutaneous lesions of Leishmania (Viannia) braziliensis-infected hamsters

Current therapeutic ways adopted for the treatment of leishmaniasis are toxic and expensive including parasite resistance is a growing problem. Given this scenario, it is urgent to explore treatment alternatives for leishmaniasis. The aim of this study was to evaluate the effect of 3-phenyl-lawsone (3-PL) naphthoquinone on Leishmania (Viannia) braziliensis infection, both in vitro and in vivo, using two local routes of administration: subcutaneous (higher dose) and tattoo (lower dose). In vitro 3-PL showed low toxicity for macrophages (CC₅₀ >3200 µM/48h) and activity against intracellular amastigotes (IC₅₀ = 193 ± 19 µM/48h) and promastigotes (IC₅₀ = 116 ± 26 µM/72h), in which induced increased ROS generation. Additionally, 3-PL up-regulated the production of cytokines such as tumor necrosis factor alpha (TNF-α), monocyte chemotactic protein 1 (MCP-1), interleukin-6 (IL-6) and IL-10 in infected macrophages. However, the anti-amastigote action was independent of nitric oxide production. Treatment of hamsters infected with L. (V.) braziliensis from one week after infection with 3-PL by subcutaneous (25 µg/Kg) or tattooing (2.5 µg/Kg) route, during 3 weeks (3 times/week) or 2 weeks (2 times/week) significantly decreased the parasite load (p<0.001) in the lesion. The reduction of parasite load by 3-PL treatment was comparable to reference drug meglumine antimoniate administered by the same routes (subcutaneous 1mg/Kg and tattoo 0.1mg/Kg). In addition, treatment started from five weeks after infection with 3-PL per tattoo also decreased the parasite load. These results show the anti-leishmanial effect of 3-PL against L. (V.) braziliensis and its efficacy by subcutaneous (higher dose) and tattoo (lower dose) routes. In addition, this study shows that drug delivery by tattooing the lesion allows the use of lower doses than the conventional subcutaneous route, which may support the development of a new therapeutic strategy that can be adopted for leishmaniasis.

A novel intradermal tattoo-based injection device enhances the immunogenicity of plasmid DNA vaccines

In recent years, tattooing technology has shown promising results toward evaluating vaccines in both animal models and humans. However, this technology has some limitations due to variability of experimental evaluations or operator procedures. The current study evaluated a device (intradermal oscillating needle array injection device: IONAID) capable of microinjecting a controlled dose of any aqueous vaccine into the intradermal space. IONAID-mediated administration of a DNA-based vaccine encoding the glycoprotein (GP) from the Ebola virus resulted in superior T- and B-cell responses with IONAID when compared to single intramuscular (IM) or intradermal (ID) injection in mice. Moreover, humoral immune responses, induced after IONAID vaccination, were significantly higher to those obtained with traditional passive DNA tattooing in guinea pigs and rabbits. This device was well tolerated and safe during HIV vaccine delivery in non-human primates (NHPs), while inducing robust immune responses. In summary, this study shows that the IONAID device improves vaccine performance, which could be beneficial to the animal and human health, and importantly, provide a dose-sparing approach (e.g., monkeypox vaccine).

Optimization and use of near infrared imaging to guide lymph node collection in rhesus macaques (Macaca mulatta)

Background

Identification of lymph nodes (LNs) draining a specific site or in obese macaques can be challenging.

Methods

Indocyanine Green (ICG) was administered intradermal (ID), intramuscular, in the oral mucosa, or subserosal in the colon followed by Near Infrared (NIR) imaging.

Results

After optimization to maximize LN identification, intradermal ICG was successful in identifying 50–100% of the axillary/inguinal LN at a site. Using NIR, collection of peripheral and mesenteric LNs in obese macaques was 100% successful after traditional methods failed. Additionally, guided collection of LNs draining the site of intraepithelial or intramuscular immunization demonstrated significantly increased numbers of T follicular helper (Tfh) cells in germinal centers of draining compared to nondraining LNs.

Conclusion

These imaging techniques optimize our ability to evaluate immune changes within LNs over time, even in obese macaques. This approach allows for targeted serial biopsies that permit confidence that draining LNs are being harvested throughout the study.

Tattoo inks are toxicological risks to human health: A systematic review of its ingredients, fate inside skin, toxicity due to polycyclic aromatic hydrocarbons, primary aromatic amines, metals, and overview of regulatory frameworks

Today, tattooing has become very popular among people all over the world. Tattooists, with the help of tiny needles, place tattoo ink inside the skin surface and unintentionally introduce a large number of unknown ingredients. These ingredients include polycyclic aromatic hydrocarbons (PAHs), heavy metals, and primary aromatic amines (PAAs), which are either unintentionally introduced along with the ink or produced inside the skin by different types of processes for example cleavage, metabolism and photodecomposition. These could pose toxicological risks to human health, if present beyond permissible limits. PAH such as Benzo(a)pyrene is present in carbon black ink. PAAs could be formed inside the skin as a result of reductive cleavage of organic azo dyes. They are reported to be highly carcinogenic by environmental protection agencies. Heavy metals, namely, cadmium, lead, mercury, antimony, beryllium, and arsenic are responsible for cancer, neurodegenerative diseases, cardiovascular, gastrointestinal, lungs, kidneys, liver, endocrine, and bone diseases. Mercury, cobalt sulphate, other soluble cobalt salts, and carbon black are in Group 2B, which means they may cause cancer in humans. Cadmium and compounds of cadmium, on the other hand, are in Group 1 (carcinogenic to humans). The present article addresses the various ingredients of tattoo inks, their metabolic fate inside human skin and unintentionally added impurities that could pose toxicological risk to human health. Public awareness and regulations that are warranted to be implemented globally for improving the safety of tattooing.

Comparative study of 1064 nm nanosecond, 1064 nm picosecond, 755 nm, and 595 nm lasers for tattoo removal: An essential role by macrophage

OBJECTIVES

Tattoo removal is in high demand, and many types of lasers can be used for tattoo removal. Macrophages play an important role in the persistence of tattoos. However, comparative studies of the efficacy of tattoo removal with different lasers versus the relationship between the destruction of pigment particles or recruitment of macrophages after laser treatment are lacking.

MATERIALS AND METHODS

Tattoo models were established on the rat dorsal surface and randomly treated with 1064 nm nanosecond, 1064 nm picosecond, 755 nm, and 595 nm lasers for one session. Clinical photographic evaluation, melanin index, hematoxylin and eosin staining, identification of macrophages by CD68 staining, and transmission electron microscopy were conducted at different time points.

RESULTS

Regardless of the pulse duration, all lasers included were effective for the removal of black tattoos, with 1064 nm lasers having the best efficacy, followed by 755 and 595 nm lasers. The diameter of the pigment particles and recruitment of dermal macrophages correlated with the efficacy of tattoo removal.

CONCLUSIONS

In this study, the 1064 nm lasers were found to be the most effective for black tattoo removal. However, there was no significant difference between the 1064 nm picosecond and the nanosecond lasers. Macrophage recruitment plays an essential role in pigment metabolism during laser-tattoo removal.

Comparative Toxicological Evaluation of Tattoo Inks on Two Model Organisms

Tattooing is a technique that introduces colored substances under the skin in order to color it permanently. Decomposition products of tattoo pigments produce numerous damages for the skin and other organs. We studied the effects of a commercial red ink tattoo, PR170, on Xenopus laevis embryos and Daphnia magna nauplii using concentrations of 10, 20, and 40 mg/L. For Xenopus, we applied the FETAX protocol analyzing survival, malformations, growth, heart rate, and the expression of genes involved in the development. In D. magna, we evaluated the toxicity with an immobilization test. Moreover, we investigated the production of ROS, antioxidant enzymes, and the expression of the ATP-binding cassette in both models. Our results indicate that PR170 pigment has nanoparticle dimensions, modifies the survival and the ATP-binding cassette activity, and induces oxidative stress that probably produces the observed effects in both models. Deformed embryos were observed in Xenopus, probably due to the modification of expression of genes involved in development. The expression of pro-inflammatory cytokines was also modified in this amphibian. We think that these effects are due to the accumulation of PR170 and, in particular, to the presence of the azoic group in the chemical structure of this pigment. Further studies needed to better understand the effects of commercial tattoo inks.

Challenges and opportunities for small volumes delivery into the skin

Each individual's skin has its own features, such as strength, elasticity, or permeability to drugs, which limits the effectiveness of one-size-fits-all approaches typically found in medical treatments. Therefore, understanding the transport mechanisms of substances across the skin is instrumental for the development of novel minimal invasive transdermal therapies. However, the large difference between transport timescales and length scales of disparate molecules needed for medical therapies makes it difficult to address fundamental questions. Thus, this lack of fundamental knowledge has limited the efficacy of bioengineering equipment and medical treatments. In this article, we provide an overview of the most important microfluidics-related transport phenomena through the skin and versatile tools to study them. Moreover, we provide a summary of challenges and opportunities faced by advanced transdermal delivery methods, such as needle-free jet injectors, microneedles, and tattooing, which could pave the way to the implementation of better therapies and new methods.

Tattoo pigment mimicking axillary lymph node calcifications on mammography

Axillary lymph nodes can appear abnormal on mammography due to uptake of tattoo pigment and a malignant cause must be excluded through diagnostic workup. Furthermore, tattoo pigment can mimic malignant pathology at surgery or confound appropriate staging of breast cancer. We present the case of a 47-year-old female with left axillary lymph nodes demonstrating new coarse densities suspicious for malignant calcifications on screening mammogram. Stereotactic guided biopsy was performed which demonstrated pigment from a recent tattoo located on the patient's back and/or flank. Awareness of current or prior tattoos in a patient is helpful to properly manage such cases.

Permanent tattooing has no impact on local sweat rate, sweat sodium concentration and skin temperature or prediction of whole-body sweat sodium concentration during moderate-intensity cycling in a warm environment

PURPOSES

This study investigated the impact of permanently tattooed skin on local sweat rate, sweat sodium concentration and skin temperature and determined whether tattoos alter the relationship between local and whole-body sweat sodium concentration.

METHODS

Thirteen tattooed men (27 ± 6 years) completed a 1 h (66 ± 4% of [Formula: see text]) cycling trial at 32 °C, 35% relative humidity. Sweat rate and sweat sodium concentration were measured using the whole-body washdown and local absorbent patch techniques. Patches and skin-temperature probes were applied over the right/left thighs and tattooed/non-tattooed (contralateral) regions.

RESULTS

Local sweat rates did not differ (p > 0.05) between the right (1.11 ± 0.38) and left (1.21 ± 0.37) thighs and the permanently tattooed (1.93 ± 0.82) and non-tattooed (1.72 ± 0.81 mg cm^-2 min^-1) regions. There were no differences in local sweat sodium concentration between the right (58.2 ± 19.4) and left (55.4 ± 20.3) thighs and the permanently tattooed (73.0 ± 22.9) and non-tattooed (70.2 ± 18.9 mmol L^-1) regions. Difference in local skin temperature between the right and left thighs (- 0.043) was similar to that between the permanently tattooed and non-tattooed (- 0.023 °C) regions. Prediction of whole-body sweat sodium concentration for the permanently tattooed (41.0 ± 6.7) and the non-tattooed (40.2 ± 5.3 mmol L^-1) regions did not differ.

CONCLUSION

Permanent tattoos do not alter local sweat rate, sweat sodium concentration or local skin temperature during moderate-intensity cycling exercise in a warm environment. Results from a patch placed over a tattooed surface correctly predicts whole-body sweat sodium concentration from an equation developed from a non-tattooed region.

Safety of tattoos and permanent make-up: a regulatory view

The continuous increase in the popularity of tattoos and permanent make-up (PMU) has led to substantial changes in their societal perception. Besides a better understanding of pathological conditions associated with the injection of highly diverse substances into subepidermal layers of the skin, their regulation has occupied regulatory bodies around the globe. In that sense, current regulatory progress in the European Union is an exemplary initiative for improving the safety of tattooing. On one hand, the compilation of market surveillance data has provided knowledge on hazardous substances present in tattoo inks. On the other hand, clinical data gathered from patients enabled correlation of adverse reactions with certain substances. Nevertheless, the assessment of risks remains a challenge due to knowledge gaps on the biokinetics of highly complex inks and their degradation products. This review article examines the strategies for regulating substances in tattoo inks and PMU in light of their potential future restriction in the frame of the REACH regulation. Substance categories are discussed in terms of their risk assessment and proposed concentration limits.

Distribution of Tattoo Pigment in Lymph Nodes Dissected for Gynecological Malignancy

Tattoo pigment migrates to regional lymph nodes, often causing acute or chronic lymphadenopathy. Past reports on tattoo lymphadenopathy are almost exclusively from Western countries. However, systemic distribution of tattoo pigment in lymph nodes has not been assessed in detail. In this article, we report a Japanese case of cervical adenocarcinoma, in which we successfully assessed the distribution of tattoo pigment deposition in pelvic and para-aortic lymph nodes. A 61-year-old woman with Japanese-style tattoos on both arms and her left thigh visited another clinic with postcoital bleeding. She was diagnosed with clinical stage 1B1 (cervical adenocarcinoma) and underwent radical hysterectomy and pelvic/para-aortic lymph node dissection. Histopathological examination revealed deposition of a black pigment in multiple lymph nodes. The pigment was more abundant in the left pelvic lymph nodes than in the para-aortic lymph nodes, a finding suggestive of pigment drainage from the tattoo on the left thigh. She remains free of disease more than 1 year after surgery. The diagnosis of tattoo lymphadenopathy is not easy when clinical information is lacking. The differential diagnoses include metastatic melanoma. Clinicians and pathologists should better recognize this phenomenon.

A low inflammatory, Langerhans cell-targeted microprojection patch to deliver ovalbumin to the epidermis of mouse skin

In a low inflammatory skin environment, Langerhans cells (LCs) - but not dermal dendritic cells (dDCs) - contribute to the pivotal process of tolerance induction. Thus LCs are a target for specific-tolerance therapies. LCs reside just below the stratum corneum, within the skin's viable epidermis. One way to precisely deliver immunotherapies to LCs while remaining minimally invasive is with a skin delivery device such as a microprojection arrays (MPA). Today's MPAs currently achieve rapid delivery (e.g. within minutes of application), but are focussed primarily at delivery of therapeutics to the dermis, deeper within the skin. Indeed, no MPA currently delivers specifically to the epidermal LCs of mouse skin. Without any convenient, pre-clinical device available, advancement of LC-targeted therapies has been limited. In this study, we designed and tested a novel MPA that delivers ovalbumin to the mouse epidermis (eMPA) while maintaining a low, local inflammatory response (as defined by low erythema after 24 h). In comparison to available dermal-targeted MPAs (dMPA), only eMPAs with larger projection tip surface areas achieved shallow epidermal penetration at a low application energy. The eMPA characterised here induced significantly less erythema after 24 h (p = 0.0004), less epidermal swelling after 72 h (p < 0.0001) and 52% less epidermal cell death than the dMPA. Despite these differences in skin inflammation, the eMPA and dMPA promoted similar levels of LC migration out of the skin. However, only the eMPA promoted LCs to migrate with a low MHC II expression and in the absence of dDC migration. Implementing this more mouse-appropriate and low-inflammatory eMPA device to deliver potential immunotherapeutics could improve the practicality and cell-specific targeting of such therapeutics in the pre-clinical stage. Leading to more opportunities for LC-targeted therapeutics such as for allergy immunotherapy and asthma.

Tattoo inks: Characterization and in vivo and in vitro toxicological evaluation

Tattoo inks represent a growing market in the world economy, but this growth is associated with an increase in reports of adverse effects caused by the use of this product. In this study, four commercial tattoo inks (blue, green, red and black) were studied to characterize the composition and particle size and identify possible in vivo and in vitro toxicological effects on Daphnia magna and HaCaT cells, respectively. Compositional analysis confirmed the functional groups in the vehicles and organic pigments. The presence of nanoparticles was confirmed by image analysis. The toxicological evaluation indicated distinct results for blue and green inks for the parameters tested, despite the presence of similar levels of metals. The red ink, followed by the green, presented the highest toxicity, which may be related to pigments containing azo compounds and not to the metal fraction. Black ink was found to be the safest toxicologically. This paper provides an overview of the composition of tattoo inks and their toxicological effects in epidermal cells and in the environment.

Synchrotron-based ν-XRF mapping and μ-FTIR microscopy enable to look into the fate and effects of tattoo pigments in human skin

The increasing prevalence of tattoos provoked safety concerns with respect to particle distribution and effects inside the human body. We used skin and lymphatic tissues from human corpses to address local biokinetics by means of synchrotron X-ray fluorescence (XRF) techniques at both the micro (μ) and nano (ν) scale. Additional advanced mass spectrometry-based methodology enabled to demonstrate simultaneous transport of organic pigments, heavy metals and titanium dioxide from skin to regional lymph nodes. Among these compounds, organic pigments displayed the broadest size range with smallest species preferentially reaching the lymph nodes. Using synchrotron μ-FTIR analysis we were also able to detect ultrastructural changes of the tissue adjacent to tattoo particles through altered amide I α-helix to β-sheet protein ratios and elevated lipid contents. Altogether we report strong evidence for both migration and long-term deposition of toxic elements and tattoo pigments as well as for conformational alterations of biomolecules that likely contribute to cutaneous inflammation and other adversities upon tattooing.

The effect of early life experience, environment, and genetic factors on spontaneous home-cage aggression-related wounding in male C57BL/6 mice

Aggression is a major welfare issue in mice, particularly when mice unfamiliar to each other are first placed in cages, as happens on receipt from a vendor, and following cage cleaning. Injuries from aggression are the second leading cause of unplanned euthanasia in mice, following ulcerative dermatitis. Commonly employed strategies for reducing aggression-related injury are largely anecdotal, and may even be counterproductive. Here we report a series of experiments testing potential explanations and interventions for post-shipping aggression-related injuries in C57BL/6 mice. First, we examined the effects of weaning: testing whether manipulating weaning age reduced aggression-related injuries, and if repeated mixing of weaned mice before shipping increased these injuries. Contrary to our predictions, repeated mixing did not increase post-shipping injurious aggression, and early weaning reduced aggression-related injuries. Second, we examined potential post-shipping interventions: testing whether lavender essential oil applied to the cage reduced aggression-related injuries, and whether a variety of enrichments decreased injurious aggression. Again, contrary to predictions, lavender increased wounding, and none of the enrichments reduced it. However, consistent with the effects of weaning age in the first experiment, cages with higher mean body weight showed elevated levels of aggression-related wounding. Finally, we tested whether C57BL/6 substrains and identification methods affected levels of intra-cage wounding from aggression. We found no effect of strain, but cages where mice were ear-notched for identification showed higher levels of wounding than cages where mice were tail-tattooed. Overall, these results emphasize the multifactorial nature of home-cage injurious aggression, and the importance of testing received wisdom when it comes to managing complex behavioral and welfare problems. In terms of practical recommendations to reduce aggressive wounding in the home cage, tail tattooing is recommended over ear notching and late weaning should be avoided.

Socio-epidemiologic aspects and cutaneous side effects of permanent tattoos in Germany - Tattoos are not restricted to a specific social phenotype

Background: More and more people of all age classes have a tattoo. Intriguingly, there are multiple prejudices in the general population and published data that concern tattooed persons, such as being criminals, having a low education, being alcohol or drug abusers, or more risky in their life style. Objective: To obtain and to evaluate sociodemographic data on tattooed persons, to investigate the incidence of tattoo-related cutaneous complications and to define personal risk factors and course of the persons after being tattooed concerning behavior of personal environment. Patients and Methods: We interviewed 426 participants with already existing tattoos and 20 participants just before getting a new tattoo by using an online questionnaire. The participators were asked about socio-epidemiologic aspects of tattoos in general and special aspects of their own tattoo(s) in particular. There were no exclusion criteria. Results: Tattoos are interesting for people seeking popular body art, esp. university graduates and financially-secure individuals. 446 persons participated in this study. Most of the persons were female with a mean age of 35. Local pruritus around the tattooed area was the most common cutaneous side effect among the participants. 93.5% of the participants did not want a tattoo removal. Intriguingly, most of the participants experienced no career problems related to the tattoo(s). Limitations: The study population is not representative as we included only persons being tattooed prior to or getting newly tattooed. Furthermore, there is a potential selection bias as the participation in this study was voluntary. Only persons that felt involved by the flyer did answer the questionnaire. Conclusion: The present data shows that common tattooed persons are not low educated criminals with any drug or alcohol abuse or with risky life style. Nowadays being tattooed encompasses a kind of body art and displays a certain kind of lifestyle habit.

A medical-toxicological view of tattooing

Long perceived as a form of exotic self-expression in some social fringe groups, tattoos have left their maverick image behind and become mainstream, particularly for young people. Historically, tattoo-related health and safety regulations have focused on rules of hygiene and prevention of infections. Meanwhile, the increasing popularity of tattooing has led to the development of many new colours, allowing tattoos to be more spectacular than ever before. However, little is known about the toxicological risks of the ingredients used. For risk assessment, safe intradermal application of these pigments needs data for toxicity and biokinetics and increased knowledge about the removal of tattoos. Other concerns are the potential for phototoxicity, substance migration, and the possible metabolic conversion of tattoo ink ingredients into toxic substances. Similar considerations apply to cleavage products that are formed during laser-assisted tattoo removal. In this Review, we summarise the issues of concern, putting them into context, and provide perspectives for the assessment of the acute and chronic health effects associated with tattooing.

Tattoo Delivery of a Semliki Forest Virus-Based Vaccine Encoding Human Papillomavirus E6 and E7

The skin is an attractive organ for immunization because of the presence of antigen-presenting cells. Intradermal delivery via tattooing has demonstrated superior vaccine immunogenicity of DNA vaccines in comparison to conventional delivery methods. In this study, we explored the efficacy of tattoo injection of a tumor vaccine based on recombinant Semliki Forest virus replicon particles (rSFV) targeting human papillomavirus (HPV). Tattoo injection of rSFV particles resulted in antigen expression in both the skin and draining lymph nodes. In comparison with intramuscular injection, the overall antigen expression determined at the site of administration and draining lymph nodes was 10-fold lower upon tattoo injection. Delivery of SFV particles encoding the E6 and E7 antigens of human papillomavirus type 16 (SFVeE6,7) via tattooing resulted in HPV-specific cytotoxic T cells and in vivo therapeutic antitumor response. Strikingly, despite the observed lower overall transgene expression, SFVeE6,7 delivered via tattoo injection resulted in higher or equal levels of immune responses as compared to intramuscular injection. The intrinsic immunogenic potential of tattooing provides a benefit for immunotherapy based on an alphavirus.

Prophylactic papillomavirus vaccines

Human papillomaviruses (HPV) are the causative agents of cervical cancer, the third most common cancer in women. The development of prophylactic HPV vaccines Gardasil® and Cervarix® targeting the major oncogenic HPV types is now the frontline of cervical cancer prevention. Both vaccines have been proven to be highly effective and safe although there are still open questions about their target population, cross-protection, and long-term efficacy. The main limitation for a worldwide implementation of Gardasil® and Cervarix® is their high cost. To develop more affordable vaccines research groups are concentrated in new formulations with different antigens including capsomeres, the minor capsid protein L2 and DNA. In this article we describe the vaccines' impact on HPV-associated disease, the main open questions about the marketed vaccines, and current efforts for the development of second-generation vaccines.

Manufactured nanomaterials: categorization and approaches to hazard assessment

Nanotechnology offers enormous potential for technological progress. Fortunately, early and intensive efforts have been invested in investigating toxicology and safety aspects of this new technology. However, despite there being more than 6,000 publications on nanotoxicology, some key questions still have to be answered and paradigms need to be challenged. Here, we present a view on the field of nanotoxicology to stimulate the discussion on major knowledge gaps and the critical appraisal of concepts or dogma. First, in the ongoing debate as to whether nanoparticles may harbour a specific toxicity due to their size, we support the view that there is at present no evidence of 'nanospecific' mechanisms of action; no step-change in hazard was observed so far for particles below 100 nm in one dimension. Therefore, it seems unjustified to consider all consumer products containing nanoparticles a priori as hazardous. Second, there is no evidence so far that fundamentally different biokinetics of nanoparticles would trigger toxicity. However, data are sparse whether nanoparticles may accumulate to an extent high enough to cause chronic adverse effects. To facilitate hazard assessment, we propose to group nanomaterials into three categories according to the route of exposure and mode of action, respectively: Category 1 comprises nanomaterials for which toxicity is mediated by the specific chemical properties of its components, such as released ions or functional groups on the surface. Nanomaterials belonging to this category have to be evaluated on a case-by-case basis, depending on their chemical identity. Category 2 focuses on rigid biopersistent respirable fibrous nanomaterials with a specific geometry and high aspect ratio (so-called WHO fibres). For these fibres, hazard assessment can be based on the experiences with asbestos. Category 3 focuses on respirable granular biodurable particles (GBP) which, after inhalation, may cause inflammation and secondary mutagenicity that may finally lead to lung cancer. After intravenous, oral or dermal exposure, nanoscaled GBPs investigated apparently did not show 'nanospecific' effects so far. Hazard assessment of GBPs may be based on the knowledge available for granular particles. In conclusion, we believe the proposed categorization system will facilitate future hazard assessments.

Colocalization of cell death with antigen deposition in skin enhances vaccine immunogenicity

Vaccines delivered to the skin by microneedles – with and without adjuvants – have increased immunogenicity with lower doses than standard vaccine delivery techniques such as intramuscular (i.m.) or intradermal (i.d.) injection. However, the mechanisms behind this skin-mediated ‘adjuvant’ effect are not clear. Here, we show that the dynamic application of a microprojection array (the Nanopatch) to skin generates localized transient stresses invoking cell death around each projection. Nanopatch application caused significantly higher levels (~65-fold) of cell death in murine ear skin than i.d. injection using a hypodermic needle. Measured skin cell death is associated with modeled stresses ~1–10 MPa. Nanopatch-immunized groups also yielded consistently higher anti-IgG endpoint titers (up to 50-fold higher) than i.d. groups after delivery of a split virion influenza vaccine. Importantly, co-localization of cell death with nearby live skin cells and delivered antigen was necessary for immunogenicity enhancement. These results suggest a correlation between cell death caused by the Nanopatch with increased immunogenicity. We propose that the localized cell death serves as a ‘physical immune enhancer’ for the adjacent viable skin cells, which also receive antigen from the projections. This natural immune enhancer effect has the potential to mitigate or replace chemical-based adjuvants in vaccines.

Drug delivery by tattooing to treat cutaneous leishmaniasis

This study establishes a proof-of-concept that a tattoo device can target intra-dermal drug delivery against cutaneous leishmaniasis (CL). The selected drug is oleylphosphocholine (OlPC) formulated as liposomes, particles known to be prone to macrophage ingestion. We first show that treatment of cultured Leishmania-infected macrophages with OlPC-liposomes results in a direct dose-dependent killing of intracellular parasites. Based on this, in vivo efficacy is demonstrated using a 10 day tattooing-mediated treatment in mice infected with L. major and L. mexicana. In both models this regimen results in rapid clinical recovery with complete regression of skin lesions by Day 28. Parasite counts and histopathology examination confirm high treatment efficacy at the parasitic level. Low amount of drug required for tattooing combined with fast clinical recovery may have a positive impact on CL patient management. This first example of tattoo-mediated drug delivery could open to new therapeutic interventions in the treatment of skin diseases.

Cytokines are systemic effectors of lymphatic function in acute inflammation

The response of the lymphatic system to inflammatory insult and infection is not completely understood. Using a near-infrared fluorescence (NIRF) imaging system to noninvasively document propulsive function, we noted the short-term cessation of murine lymphatic propulsion as early as 4h following LPS injection. Notably, the effects were systemic, displaying bilateral lymphatic pumping cessation after a unilateral insult. Furthermore, IL-1β, TNF-α, and IL-6, cytokines that were found to be elevated in serum during lymphatic pumping cessation, were shown separately to acutely and systemically decrease lymphatic pulsing frequency and velocity following intradermal administration. Surprisingly, marked lymphatic vessel dilation and leakiness were noted in limbs contralateral to IL-1β intradermal administration, but not in ipsilateral limbs. The effects of IL-1β on lymphatic pumping were abated by pre-treatment with an inhibitor of inducible nitric oxide synthase, L-NIL (N-iminoethyl-L-lysine). The results suggest that lymphatic propulsion is systemically impaired within 4h of acute inflammatory insult, and that some cytokines are major effectors of lymphatic pumping cessation through nitric oxide-mediated mechanisms. These findings may help in understanding the actions of cytokines as mediators of lymphatic function in inflammatory and infectious states.

Comparison of ear tattoo, ear notching and microtattoo in rats undergoing cardiovascular telemetry

Individual and permanent identification of experimental animals is a common and often essential research practice. There is little information available on the short-term effects of these procedures on the animals. In this study, seven rats were implanted with telemetric devices. The effects of three different identification methods (ear tattoo, ear notching and microtattoo) were compared. Cardiovascular data were collected for 24 h after the procedures. Time periods of 0-1, 1-4, 4-16 h (dark) and 16-24 h after the procedure were analysed separately. The most pronounced differences in measured parameters were observed during the first hour after the procedures were performed. Mean arterial pressure (MAP) was significantly higher (P < 0.012) following the ear tattoo than the microtattoo procedure by a difference of approximately 5 mmHg. Heart rate (HR) was significantly elevated (P < 0.001) after ear tattoo compared with both ear notching (Δ = 31 beats per minute [bpm]) and microtattoo (Δ = 44 bpm). During the 1-4 h period and the following dark period, the MAP was highest in the ear notching group, but no differences were observed in the HRs. During the following dark period (4-16 h) and the next day (16-24 h) differences in MAP and HR were minor. In conclusion, microtattoo appears to cause the mildest changes in HR and blood pressure. Based on these results, ear tattoo and ear notching should be replaced by microtattoo whenever possible.

Vaccination with human papillomavirus type 16-derived peptides using a tattoo device

Tattooing has been shown to be very efficient at inducing immunity by vaccination with DNA vaccines. In this study, we examined the usability of tattooing for delivery of peptide vaccines. We compared tattooing with subcutaneous (s.c.) needle injection using peptides derived from human papillomavirus type 16 (HPV16) proteins. We observed that higher peptide-specific immune responses were elicited after vaccination with the simple peptides (E7(44-62) and E7(49-57)) and keyhole limpet hemocyanin-(KLH)-conjugated peptides (E7(49-57), L2(18-38) and L2(108-120)) with a tattoo device compared to s.c. inoculation. The administration of the synthetic oligonucleotide containing immunostimulatory CpG motifs (ODN1826) enhanced the immune responses developed after s.c. injection of some peptides (E7(44-62), KLH-conjugated L2(18-38) and L2(108-120)) to levels close to or even comparable to those after tattoo delivery of identical peptides with ODN1826. The highest efficacy of tattooing was observed in combination with ODN1826 for the vaccination with the less immunogenic E6(48-57) peptide and KLH-conjugated and non-conjugated E7(49-57) peptides which form the visible aggregates that could negatively influence the development of immune responses after s.c. injection but probably not after tattooing. In summary, we first evidenced that tattoo administration of peptide vaccines that might be useful in some cases efficiently induced both humoral and cell-mediated immune responses.

DNA-vaccination via tattooing induces stronger humoral and cellular immune responses than intramuscular delivery supported by molecular adjuvants

Tattooing is one of a number of DNA delivery methods which results in an efficient expression of an introduced gene in the epidermal and dermal layers of the skin. The tattoo procedure causes many minor mechanical injuries followed by hemorrhage, necrosis, inflammation and regeneration of the skin and thus non-specifically stimulates the immune system. DNA vaccines delivered by tattooing have been shown to induce higher specific humoral and cellular immune responses than intramuscularly injected DNA. In this study, we focused on the comparison of DNA immunization protocols using different routes of administrations of DNA (intradermal tattoo versus intramuscular injection) and molecular adjuvants (cardiotoxin pre-treatment or GM-CSF DNA co-delivery). For this comparison we used the major capsid protein L1 of human papillomavirus type 16 as a model antigen. L1-specific immune responses were detected after three and four immunizations with 50 μg plasmid DNA. Cardiotoxin pretreatment or GM-CSF DNA co-delivery substantially enhanced the efficacy of DNA vaccine delivered intramuscularly by needle injection but had virtually no effect on the intradermal tattoo vaccination. The promoting effect of both adjuvants was more pronounced after three rather than four immunizations. However, three DNA tattoo immunizations without any adjuvant induced significantly higher L1-specific humoral immune responses than three or even four intramuscular DNA injections supported by molecular adjuvants. Tattooing also elicited significantly higher L1-specific cellular immune responses than intramuscularly delivered DNA in combination with adjuvants. In addition, the lymphocytes of mice treated with the tattoo device proliferated more strongly after mitogen stimulation suggesting the presence of inflammatory responses after tattooing. The tattoo delivery of DNA is a cost-effective method that may be used in laboratory conditions when more rapid and more robust immune responses are required.

Delayed presentation of tattoo lymphadenopathy mimicking malignant melanoma lymphadenopathy

Tattooing is a popular cosmetic practice and the technique has been adopted in breast reconstruction. Pigment injected intradermally is transported to lymph nodes leading to permanent pigmentation. Differential diagnosis between melanoma and tattoo pigmentation of lymph nodes is done microscopically. We present the case study of a patient who presented with palpable and pigmented axillary lymph nodes, 2 years after excision of melanoma and 20 years after tattooing. Intraoperative finding of enlarged, pigmented lymph nodes is not a certain sign of metastasis, as causes other then melanoma can lead to pigmented lymphadenopathy. The diagnostic and investigation process should start with history (including history of previous tattooing) and fine needle aspiration (FNA) of enlarged lymph node. If FNA is negative an open biopsy should be performed for confirmation of diagnosis before proceeding to completion lymphadenectomy.

Establishment of an Extraction Method for the Recovery of Tattoo Pigments from Human Skin Using HPLC Diode Array Detector Technology

Tattooing is a widespread process of puncturing pigments into skin, whereas the resulting concentration inside the skin remains unknown. Many tattoo colorants are organic pigments, such as azo pigments, manufactured for other uses. To remove tattoos from skin, laser pulses at very high intensities are applied to the skin to destroy the tattoo pigments. Recent investigations have shown that several azo compounds are cleaved by laser light leading to potentially toxic or carcinogenic compounds. To assess the risk of tattooing and laser treatment of tattoos, the concentration of the pigments and their decomposition products in the skin must be determined. Therefore, an extraction method was established to determine the concentration of tattoo pigments and decomposition products quantitatively. The extraction of two widely used azo compounds, Pigment Red 22 and Pigment Red 9, and their laser-induced decomposition products, 2-methyl-5-nitroaniline, 4-nitrotoluene, 2,5-dichloraniline, and 1,4-dichlorobenzene, was accomplished using recovery experiments and HPLC-DAD technology. Despite the poor solubility of the pigments, a nearly complete recovery from aqueous suspension (> 92%) or lysed skin (> 94%) was achieved. The decomposition products were extracted from aqueous suspension or skin showing a recovery of up to 100%, except for the very volatile 1,4-DCB.

Tattoos: a review of tattoo practices and potential treatment options for removal

PURPOSE OF REVIEW

The purpose of this review is to present an overview of tattoo practices, complications and treatment options relevant to the pediatric population.

RECENT FINDINGS

Tattoos are popular among adolescents for a variety of reasons and may be associated with other high-risk behaviors. Research indicates that adolescents may not comprehend potential health risks and complications that are related to tattooing. Case reports of infection, tattoo-associated dermatoses, and allergic reactions to tattoos continue to be reported in the literature. Additional cases of allergic contact dermatitis are being reported with temporary henna tattooing and cosmetic tattoos. As the desire for tattoo removal increases, researchers continue to explore safe, innovative and efficacious methods of tattoo removal.

SUMMARY

As the popularity of tattooing continues to rise, so do the potential complications and adverse effects. Treatment options for tattoos are well described and must be individualized to each patient. Lasers continue to be a reliable and efficacious tool in treating amateur, professional, cosmetic and traumatic tattoos.

Labor analgesia for the parturient with lumbar tattoos: what does an obstetrician need to know?

Tattoos-ancient forms of permanent body ornamentation (body art) have today become popular fashion accessories worldwide. More than 50% of all tattoos are being done on women. In the recent years body tattooing in unconventional sites (e.g. lumbar and/or sacral area, lower abdomen, breast, and buttocks) has gained increasing popularity among young women (including in pregnancy). Although, the potential hazards of regional anesthesia in patients with lumbar tattoos remain controversial it may seem prudent to avoid a hollow needle insertion (possible tissue entrapment in its bore as the needle passes to the deeper structures) through a tattoo for neuraxial blocks. This author is not aware of any other review articles in English literature discussing implications, and complications of labor analgesia in parturients presenting with lumbar tattoos.