Temperature-Induced Changes in Structural and Physicochemical Properties of Vernix Caseosa

How do the skin barrier and microbiome adapt to the extra-uterine environment after birth? Implications for the clinical practice

The multiple protective functions of the skin derive from the interactions between epithelial skin and immune cells as well as the commensal microbiota. Developed in the last trimester of intra-uterine life, the skin barrier adapts dynamically after birth. Specific differences in the structure and physiology have been disclosed between infant and adult skin. The stratum corneum of infants is thinner and structured by thicker corneocytes with a more anisotropic surface in comparison to adult skin. Lower levels of the natural moisturizing factor and its constituents, together with the increased protease activity in the epidermis result in dry baby skin and ongoing adaptation of the desquamation to the extra-uterine environment. Infant epidermis is characterized by an accelerated proliferation rate and clinically competent permeability barrier in term neonates, despite the higher baseline values of transepidermal water loss in infants. The skin surface of newborns is less acidic, which could increase susceptibility to diaper and atopic dermatitis. Immediately after birth, skin is colonized by commensal bacteria-a process dependent on the mode of delivery and of major importance for the maturation of the immune system. Skin bacterial diversity and dysbiosis have been related to different pathology such as atopic and seborrheic dermatitis. This paper focuses on the ongoing structural, functional and biochemical adaptation of the human skin barrier after birth. We discuss the interactions on the 'skin barrier/ microbiota/ immune system' axis and their role in the development of competent functional integrity of the epidermal barrier.

The effect of delaying first bathing on skin barrier function in late preterm infants: A study protocol for multi-centre, single-blind RCT

AIMS

The study aims to examine the effect of delaying first bathing on skin barrier function, body temperature, and neonatal comfort of late preterm infants.

DESIGN

This study is a multi-centre, single-blind, prospective randomized controlled trial.

METHODS

We attempt to report this randomized controlled trial to comply with the SPIRIT. The study population will consist of 80 late preterm infants born at three centres (hospitals) in Turkey. The study, between September 2020-September 2021 will be held in the Neonatal Intensive Care Unit. The participants will be randomly divided into two groups, each with different bathing times. The first group (N = 40) will be bathed between 24-48 hr after birth and the second group (N = 40) will be bathed between 48-72 hr after birth. Each group's intervention will be performed by a blinded researcher. The infants' transepidermal water loss, body temperature, and comfort level will be measured before the bath and again at three times after the bath. The measurements will be taken by a blinded researcher and blinded nurse.

DISCUSSION

The benefits of infant bathing are known. However, the effect of delaying first bathing of late preterm infants on skin barrier function is unknown. At the same time, the effect of delaying bathing on maintaining body temperature and neonatal comfort is unknown.

IMPACT

This study is expected to provide a piece of credible evidence of the delay of first bathing and benefit of neonatal care in this population. It is thought that postponing bathing time of late preterm infants to 48-72 hr after birth will lead to a protective effect on skin barrier and temperature. It will be performed in clinical practice if it can effectively improve transepidermal water loss and heat loss.

TRIAL REGISTRATION

It was registered at ClinicalTrials.gov in January 2020 (NCT04231799).

Effects of Delayed Newborn Bathing on Breastfeeding, Hypothermia, and Hypoglycemia

OBJECTIVE

To determine whether delaying the newborn bath by 24 hours increases the prevalence of breastfeeding initiation and exclusive breastfeeding at discharge in healthy full-term and late preterm newborns (34 0/7-36 6/7 weeks gestation) and to examine the effect of delayed newborn bathing on the incidences of hypothermia and hypoglycemia.

DESIGN

Pre-post implementation, retrospective, cohort study.

SETTING

Provincial children's hospital with an average of 2,500 births per year.

PARTICIPANTS

Healthy newborns (N = 1,225) born at 34 0/7 weeks or more gestation who were admitted to the mother-baby unit.

METHODS

We compared newborns who were bathed before 24 hours (n = 680, preimplementation group) to newborns who were bathed after 24 hours (n = 545, postimplementation group).

RESULTS

After adjustment for confounders, the odds of exclusive breastfeeding at discharge were 33% greater in the postimplementation group than in the preimplementation group (adjusted odds ratio = 1.334; 95% confidence interval [1.049,1.698]; p = .019). Delayed bathing was associated with decreased incidence of hypothermia and hypoglycemia (p = .007 and p = .003, respectively). We observed no difference in breastfeeding initiation between groups.

CONCLUSION

Delaying the newborn bath for 24 hours was associated with an increased likelihood of exclusive breastfeeding at discharge and a decreased incidence of hypothermia and hypoglycemia in healthy newborns. The implementation of a delayed bathing policy has the potential to improve breastfeeding rates and reduce the incidence of hypothermia and hypoglycemia.

To Bathe or Not to Bathe: The Neonatal Question

After delivery, newborns go through a series of physiologic changes in an effort to adapt to extrauterine life, with preterm newborns more likely to experience medical problems following this transition. Neonatal hypothermia, defined as a temperature <36.5 °C, is a major contributor to neonatal mortality and morbidity. Early bathing may be a contributing factor to hypothermia and interfere with the premature neonate's ability to safely adapt to an extrauterine environment. Skin physiology, the physiologic changes that result from bathing, the importance of maintaining vernix for temperature stability, and how policy change and education-based programs for developmentally supportive care will be discussed in an attempt to improve patient care outcomes for neonates in the NICU.

Functional skin adaptation in infancy - almost complete but not fully competent

Early postnatal life is a period of active functional reorganization and cutaneous physiological adaptation to the extrauterine environment. Skin as the outermost organ of mammalians is endowed of multiple functions such as protection, secretion, absorption and thermoregulation. Birth stimulates the epidermal barrier maturation and the skin surface acidification especially in premature infants. In full-term infants the developed stratum corneum accomplishes competent barrier function, in contrast to prematures. Complete barrier maturation in preterm infants is fulfilled by 2-4 weeks of the postnatal life. However, in preterms with 23-25 weeks gestational age this process takes longer. Versatile regulatory mechanisms, namely skin surface acidity, calcium ion gradient and nuclear hormone receptors/ligands are interrelated in the complex postnatal newborn adaptation. The skin of newborns is adjusting quickly to the challenging environmental conditions of the postpartum. However, certain functions, for example, microcirculation, continue to develop even beyond the neonatal period, that is, up to the age of 14-17 weeks. Different environmental factors (for instance, dry and cold climate, diapers and cosmetic care procedures) influence the postnatal development of skin functional parameters such as stratum corneum hydration and the permeability barrier especially in premature infants. The aim of this article is to summarize the current knowledge on skin physiology in newborn and infants with a practical approach and to discuss the possible clinical consequences. This review offers the readership a critical and practical overview of skin physiology in newborns and infants. It emphasizes possible new research fields in neonatal and infantile skin physiology.

Long periodicity phase in extracted lipids of vernix caseosa obtained with equilibration at physiological temperature

The outermost layer of the skin, the stratum corneum (SC), comprises the main barrier function between body and environment. The SC features a highly structured lipid organization: a short periodicity phase and a long periodicity phase (LPP) with a repeat distance of 6 and 13 nm, respectively. Like SC, vernix caseosa (VC), the creamy white skin-surface biofilm of the newborn, also contains barrier lipids, i.e. ceramides, cholesterol and free fatty acids. Aim of this study was to investigate whether isolated VC lipids also form the characteristic LPP. Several preparation methods were examined and only when the solution of the lipid mixture, isolated either from VC or SC, was dried under nitrogen at 37 degrees C and subsequently spread onto a support, the LPP was formed. When VC barrier lipids were first exposed to elevated temperatures and subsequently cooled down, the LPP was formed at around 34 degrees C, which is at a much lower temperature than observed with the lipids in SC. In conclusion, we showed for the first time that depending on the preparation method, (i) VC lipids also form the LPP and (ii) the LPP in VC lipids and SC lipids was obtained at a low equilibration temperature, mimicking the physiological condition.