Skin maturation from birth to 10 years of age: Structure, function, composition and microbiome

Transdermal delivery of timolol maleate using hydrogel microneedles for the treatment of infantile haemangiomas

Infantile haemangioma (IH), the most prevalent vascular tumour in infants, requires early intervention because of the potential complications in critical areas such as the head and face. Current treatments, including topical timolol maleate (TIM), face challenges such as poor compliance, low drug utilisation, and lengthy treatment durations. In this study, we developed a hydrogel microneedle (MN) using photocurable bovine serum albumin methacryloyl (BSAMA) as a carrier for TIM. Our results showed the controlled release of TIM from BSAMA-TIM MNs, with approximately 69 % release ratio within 72 h. In-vivo studies on nude mice demonstrated that BSAMA-TIM-MNs inhibited the growth of haemangioma xenografts. Our TIM-delivering MNs exhibited high therapeutic efficacy, minimal cytotoxicity, and reduced dosing frequency. In conclusion, BSAMA-TIM MNs provide a promising strategy for treating IH.

Laser Surgery in Pediatric Skin of Color Patients: A Systematic Review

There are unique challenges in treating dermatologic conditions with lasers in pediatric patients with skin of color. Melanin in the basal epidermis scatters thermal energy, reducing laser effectiveness and increasing the risk of adverse effects. This systematic review summarizes laser treatment of dermatological conditions in pediatric patients with Fitzpatrick skin types (FST) IV-VI, reviewing laser parameters, efficacy, and potential side effects in this vulnerable population. Twenty-three studies using various designs were included after screening, with a total of 164 patients, aged 1 month-17 years. Our systematic review demonstrates that laser surgery in children with FST IV-VI is an excellent option for various dermatological conditions. Children with skin of color should not be excluded from laser surgery, as early treatment can lead to improved clearance and better clinical results. However, laser surgery in this population requires careful consideration regarding laser parameters and desired clinical outcomes. Trial Registration: Prospero ID CRD42024524971.

Effect of Almond and Extra Virgin Olive Oils on Maintaining Skin Integrity in Neonates Admitted to the Neonatal ICU

OBJECTIVE

To evaluate the effects of extra-virgin olive and almond oils on maintaining skin integrity in neonates admitted to the neonatal ICU.

METHODS

This was a semiexperimental study. The sample comprised 120 term (37-42 weeks) neonates treated in a state hospital in Istanbul, Turkey (May-August 2023), who met the sample criteria (olive oil: 60, almond oil: 60). The data were collected using a newborn identification form, the Neonatal Skin Condition Score, and the DMM Skin Moisture Meter.

RESULTS

The neonates' sex, gestational age, postnatal age, birth weight, length, and head circumference measurements were similar, suggesting no significant differences between the groups (Ps > .05). A statistically significant difference was found between the mean skin hydration levels of neonates treated with almond oil and extra-virgin olive oil on the first, second, and third days of the application, where a higher skin hydration was determined in the extra-virgin olive oil group (P = .024, P = .004, P = .020). However, no statistically significant difference was found between the Neonatal Skin Condition Score scores of neonates treated with almond oil and extra-virgin olive oil before and on all days of the application (1-5 days, P > .05).

CONCLUSIONS

Both extra-virgin olive oil and almond oil increased the stratum corneum hydration in term neonates. The application of extra-virgin olive oil and almond oil did not result in any adverse effects on neonatal skin conditions of neonates admitted to the neonatal ICU.

Chronological maturation of the skin immune barrier is topographically different

Adult skin varies across regions, with differences in chemical, physical, microbiota, and immune barriers. However, data on topographical immune differences in other age groups are limited. This study aimed to explore the chronological maturation of the immune barrier in various skin regions. A TaqMan low-density array and immunohistochemical and immunofluorescence detection of various immune cells and mediators in sebaceous gland-rich (SGR) and gland-poor (GP) healthy skin were performed in children, adolescents, and adults. The maturation of SGR skin showed a general upward trend in the mRNA levels of most Th17-related molecules with a significant increase in IL-1B from childhood to adulthood, but with only a slight elevation between childhood and adolescence. In addition, T cell, Treg, dendritic cell (DC) counts, as well as the levels of several Th17-related proteins (IL-17, IL-10, IL-23, CCL20, S100A8, sfTSLP, LCN2), increased significantly with age. In GP skin, AHR mRNA levels decreased, while Th17-related protein levels increased, although only moderately. When comparing the two regions, SGR and GP skin were similar in childhood, with differences emerging in adolescence and becoming significant in adulthood, particularly in the IL-17 pathway, mainly produced by Th17 cells. Our results show a similarly directed maturation process in GP and SGR regions, with more pronounced development of the SGR skin immune barrier (with more immune cell infiltration and cytokine production) during and after the adolescence. This is likely to be related to the significant changes in the chemical and microbiota barriers of the SGR skin during adolescence, and may explain the high incidence of inflammatory skin diseases on the SGR skin of adolescents, highlighting the need for targeted skin care in this region.

The Neonatal Microbiome: Implications for Amyotrophic Lateral Sclerosis and Other Neurodegenerations

Most brain development occurs in the "first 1000 days", a critical period from conception to a child's second birthday. Critical brain processes that occur during this time include synaptogenesis, myelination, neural pruning, and the formation of functioning neuronal circuits. Perturbations during the first 1000 days likely contribute to later-life neurodegenerative disease, including sporadic amyotrophic lateral sclerosis (ALS). Neurodevelopment is determined by many events, including the maturation and colonization of the infant microbiome and its metabolites, specifically neurotransmitters, immune modulators, vitamins, and short-chain fatty acids. Successful microbiome maturation and gut-brain axis function depend on maternal factors (stress and exposure to toxins during pregnancy), mode of delivery, quality of the postnatal environment, diet after weaning from breast milk, and nutritional deficiencies. While the neonatal microbiome is highly plastic, it remains prone to dysbiosis which, once established, may persist into adulthood, thereby inducing the development of chronic inflammation and abnormal excitatory/inhibitory balance, resulting in neural excitation. Both are recognized as key pathophysiological processes in the development of ALS.

Povidone-iodine-induced scalp lesions in pediatric neurosurgery patients: a case series

PURPOSE

Povidone-iodine, or Betadine® (Atlantis Consumer Healthcare Inc., Bridgewater, NJ), is a commonly used agent for surgical site preparation. Although commonly used, it carries the risk of skin reactions, and multiple cases of intra-operative contact dermatitis and chemical burns have been reported. However, to our knowledge, there are currently no published cases of povidone-iodine-induced skin lesions in neurosurgical patients.

METHODS

A single-center retrospective chart review was performed to identify patients who developed scalp lesions secondary to chemical toxicity following neurosurgical procedures between October 1, 2021, and June 30, 2024.

RESULTS

Three patients were identified, ranging from 2.5 months to 14 years old. Two were positioned prone and the third in lateral decubitus. All patients' heads were supported by a horseshoe headrest covered with a gel pad and wrapped in a cotton roll. For two patients, Reston™ foam (3M©, St. Paul, MN) was added on the horseshoe. Surgical sites were prepped with isopropyl alcohol, Betadine®, and chlorohexidine. Two patients had their heads intermittently lifted throughout the procedure. Lesions were identified immediately after returning the patient to the supine position in the operating room and steadily improved over the course of one to five months with local wound care.

CONCLUSIONS

Careful preparation of the surgical site is an essential step in the prevention of surgical site infections. However, caution should be exercised during skin preparation to avoid pooling of povidone-iodine around dependent regions. Additional steps, such as scheduled head elevations and pressure dispersion, should be taken to mitigate factors contributing to these lesions.

Changes in Skin Barrier Function in Neonates: Daily Variation and Impact of Bathing

BACKGROUND

The skin barrier function is an important predictor of neonatal barrier defects. This study aimed to investigate the daily changes in skin barrier function and the impact of bathing on skin barrier function in neonates.

METHODS

We assessed the transepidermal water loss (TEWL) and stratum corneum hydration (SCH) on the forehead, cheek, volar forearm, and chest from days 2 to 7 and at 1 month after birth. Additionally, we measured the values after bathing and compared them with the pre-bathing values.

RESULTS

Sixty-six neonates were involved in the assessment, and each value at the four sites showed significant correlations. TEWL remained stable between days 2 and 7, but SCH significantly increased at most sites. Both significantly increased by 1.5-2 times in 1 month. After bathing, TEWL increased by more than 20% but decreased again after 3 h.

CONCLUSIONS

TEWL did not change significantly with age during the first week of life. To minimize the effects of bathing, TEWL should be measured at least 3 h after bathing.

Uncovering key mechanisms and intervention therapies in aging skin

Advancements in understanding skin aging mechanisms, which encompass both external and internal aging processes, have spurred the development of innovative treatments primarily aimed at improving cosmetic appearance. These findings offer the potential for the development of novel therapeutic strategies aimed at achieving long-term, non-therapy-dependent clinical benefits, including the reversal of aging and the mitigation of associated health conditions. Realizing this goal requires further research to establish the safety and efficacy of targeting aging-related skin changes, such as pigmentation, wrinkling, and collagen loss. Systematic investigation is needed to identify the most effective interventions and determine optimal anti-aging treatment strategies. These reviews highlight the features and possible mechanisms of skin aging, as well as the latest progress and future direction of skin aging research, to provide a theoretical basis for new practical anti-skin aging strategies.

Chlorhexidine gluconate for antisepsis in preterm neonates: A review of safety and efficacy

Sepsis is a leading cause of death in preterm neonates. The increased susceptibility to sepsis is due to prolonged hospitalization, the need for invasive procedures, and immaturity of innate and adaptive immunity. Chlorhexidine gluconate is a popular topical disinfectant that was not recommended for use in preterm neonates until 2012. Thus, there are few studies assessing the role of chlorhexidine gluconate in antisepsis for preterm neonates. A better understanding of the safety and efficacy of chlorhexidine gluconate as an antiseptic agent for preterm neonates is the first step in establishing best practice guidelines for this population.

Clinical efficacy of a multilamellar cream on skin physiology and microbiome in an epidermal stress model: A controlled double-blinded study

INTRODUCTION

Stratum corneum (SC) is essential for skin barrier function, mitigating water loss and shielding against potentially harmful substances and allergens. The SC's lipid matrix, arranged in a lamellar structure, is integral to its protective role. Our study explores the restoration effects of a multilamellar cream with an acidic pH compared to a basic placebo cream on skin physiology and its interaction with the skin microbiome after stress induction via tape stripping (TS).

MATERIALS AND METHODS

In this double-blind study, 14 healthy participants aged 21-58 years were assessed pre- and post-tape stripping, followed by a 14 days application of a multilamellar test cream and a placebo cream with evaluations on days 7, 14 and 17 for sustained effects. Skin physiology was analysed in terms of epidermal barrier function, SC hydration and surface pH. The microbiome was analysed by 16S rRNA amplicon sequencing the 16S rRNA gene using Illumina MiSeq, with subsequent species identification.

RESULTS

Our study showed significant improvements in skin barrier repair and SC hydration with verum, particularly after 14 days of application, while both creams initially enhanced stratum corneum hydration. No significant changes in surface-pH were detected. The skin microbiome analysis revealed that TS slightly decreased alpha diversity, a trend that verum significantly reversed, enhancing diversity beyond baseline levels after 14 days. Overall, while both creams contributed to a broader microbial phyla diversity over time, no significant changes in the abundance of specific genera or species were noted between treatments.

DISCUSSION AND CONCLUSION

Our study delineates the efficacy of a pH-optimized multilamellar cream in enhancing epidermal barrier recovery and SC hydration post-sequential TS, in contrast to an unstructured basic placebo. Verum cream significantly improved skin barrier function and SC hydration at day 14, with sustained effects evident beyond the treatment period. Furthermore, the multilamellar formulation facilitated the restitution of cutaneous microbiome diversity, a key indicator of healthy skin ecology, underscoring the symbiotic relationship between barrier integrity and microbial composition. These findings underscore the importance of multilamellar emollient structures in dermatological therapeutics, with potential implications for the design of advanced skincare interventions that holistically support cutaneous resilience and homeostasis.

A systematic review and meta-analysis of nutritional and dietary interventions in randomized controlled trials for skin symptoms in children with atopic dermatitis and without food allergy: An EAACI task force report

This systematic review and meta-analysis aimed to consolidate evidence on dietary interventions for atopic eczema/dermatitis (AD) skin symptoms in children without food allergies, following PRISMA 2020 guidelines. Systematic review updates were conducted in May 2022 and June 2023, focusing on randomized placebo-controlled trials (RCTs) involving children with AD but without food allergies. Specific diets or supplements, such as vitamins, minerals, probiotics, prebiotics, symbiotics, or postbiotics, were explored in these trials. Exclusions comprised descriptive studies, systematic reviews, meta-analyses, letters, case reports, studies involving elimination diets, and those reporting on food allergens in children and adolescents. Additionally, studies assessing exacerbation of AD due to food allergy/sensitization and those evaluating elimination diets' effects on AD were excluded. Nutritional supplementation studies were eligible regardless of sensitization profile. Evaluation of their impact on AD clinical expression was performed using SCORAD scores, and a meta-analysis of SCORAD outcomes was conducted using random-effect models (CRD42022328702). The review encompassed 27 RCTs examining prebiotics, Vitamin D, evening primrose oil, and substituting cow's milk formula with partially hydrolyzed whey milk formula. A meta-analysis of 20 RCTs assessing probiotics, alone or combined with prebiotics, revealed a significant reduction in SCORAD scores, suggesting a consistent trend in alleviating AD symptoms in children without food allergies. Nonetheless, evidence for other dietary interventions remains limited, underscoring the necessity for well-designed intervention studies targeting multiple factors to understand etiological interactions and propose reliable manipulation strategies.

Longitudinal Correlations between Molecular Compositions of Stratum Corneum and Breast Milk Factors during Infancy: A Prospective Birth Cohort Study

Breast milk contains numerous factors that are involved in the maturation of the immune system and development of the gut microbiota in infants. These factors include transforming growth factor-β1 and 2, immunoglobin A, and lactoferrin. Breast milk factors may also affect epidermal differentiation and the stratum corneum (SC) barrier in infants, but no studies examining these associations over time during infancy have been reported. In this single-center exploratory study, we measured the molecular components of the SC using confocal Raman spectroscopy at 0, 1, 2, 6, and 12 months of age in 39 infants born at our hospital. Breast milk factor concentrations from their mothers' breast milk were determined. Correlation coefficients for the two datasets were estimated for each molecular component of the SC and breast milk factor at each age and SC depth. The results showed that breast milk factors and molecular components of the SC during infancy were partly correlated with infant age in months and SC depth, suggesting that breast milk factors influence the maturation of the SC components. These findings may improve understanding of the pathogenesis of skin diseases associated with skin barrier abnormalities.

Characterization of Skin Interfollicular Stem Cells and Early Transit Amplifying Cells during the Transition from Infants to Young Children

In the interfollicular epidermis, keratinocyte stem cells (KSC) generate a short-lived population of transit amplifying (TA) cells that undergo terminal differentiation after several cell divisions. Recently, we isolated and characterized a highly proliferative keratinocyte cell population, named "early" TA (ETA) cell, representing the first KSC progenitor with exclusive features. This work aims to evaluate epidermis, with a focus on KSC and ETA cells, during transition from infancy to childhood. Reconstructed human epidermis (RHE) generated from infant keratinocytes is more damaged by UV irradiation, as compared to RHE from young children. Moreover, the expression of several differentiation and barrier genes increases with age, while the expression of genes related to stemness is reduced from infancy to childhood. The proliferation rate of KSC and ETA cells is higher in cells derived from infants' skin samples than of those derived from young children, as well as the capacity of forming colonies is more pronounced in KSC derived from infants than from young children's skin samples. Finally, infants-KSC show the greatest regenerative capacity in skin equivalents, while young children ETA cells express higher levels of differentiation markers, as compared to infants-ETA. KSC and ETA cells undergo substantial changes during transition from infancy to childhood. The study presents a novel insight into pediatric skin, and sheds light on the correlation between age and structural maturation of the skin.

Preclinical Atopic Dermatitis Skin in Infants: An Emerging Research Area

Whereas clinically apparent atopic dermatitis (AD) can be confirmed by validated diagnostic criteria, the preclinical phenotype of infants who eventually develop AD is less well-characterized. Analogous to unaffected or nonlesional skin in established AD, clinically normal-appearing skin in infants who will develop clinical AD has distinct changes. Prospective studies have revealed insights into this preclinical AD phenotype. In this study, we review the structural, immunologic, and microbiome nature of the preclinical AD phenotype. Determination of markers that predict the development of AD will facilitate targeting of interventions to prevent the development or reduce the severity of AD in infants.

The Skin Microbiome and its Significance for Dermatologists

The skin is a physical and immunological barrier to the external environment. Its large surface area is colonized by diverse communities of microorganisms, including bacteria, viruses, fungi, and Demodex species mites. These microorganisms and their genetic material together create the skin microbiome. Physiologic and anatomic properties of skin sites create biogeographical habitats (dry, moist, and sebaceous) where distinct microbiota communities reside. Although, in general, the composition of these habitats is maintained from person to person, the skin microbiome of an individual also has unique microbial features. Dysbiosis occurs when the normal abundance, composition, or location of the microbiota is changed, most notably there is a decrease in flora diversity. Certain skin diseases, including atopic dermatitis, rosacea, and psoriasis are associated with cutaneous dysbiosis, and even disruption of the gut microbiota. Studies have shown that current treatments for these dermatologic conditions can alter/stabilize the skin microbiome, and there is emerging research detailing the impact of prebiotics, probiotics, and postbiotics on these conditions. Although clinical guidelines do not currently exist, clinical studies support the safety and possible benefits of using topical prebiotics and postbiotics and oral probiotics for a variety of skin conditions. Until such guidelines exist, utilizing carefully designed clinical studies to inform clinical practice is recommended.