William L Pickens

Vernix Caseosa in Neonatal Adaptation

OBJECTIVES:To characterize vernix caseosa in newborn infants with respect to factors that influence vernix distribution on the skin surface, vernix effects on thermal stability, skin hydration, acid mantle development, and vernix antioxidant properties.STUDY DESIGN:Vernix distribution was determined for 430 infants. Thermal stability was assessed in parallel groups following vernix retention (n=66) and removal (n=64). The effects of vernix retention on skin hydration, pH, erythema, and dryness/scaling were determined. Samples were analyzed for vitamin E before and after UV exposure.RESULTS:Vernix distribution depended upon gestational age, delivery mode, gender, race, and meconium exposure. Retention had no effect on axillary temperatures. Skin hydration was significantly higher for vernix-retained skin. Skin pH and erythema were significantly lower with retention. Vitamin E levels were decreased by ultraviolet radiation.CONCLUSIONS:Vernix is a naturally occurring barrier cream with multiple salubrious effects, which support its retention on the skin surface at birth.

Interaction Between Pulmonary Surfactant and Vernix: A Potential Mechanism for Induction of Amniotic Fluid Turbidity

The development of amniotic fluid turbidity during the third trimester is a known marker of fetal lung maturity. We hypothesized that this turbidity results from detachment of vernix caseosa from the fetal skin secondary to interaction with pulmonary-derived phospholipids in the amniotic fluid. To test this hypothesis, we exposed vernix to bovine-derived pulmonary surfactant over a physiologically relevant concentration range. Ten milligrams of vernix was evenly applied to the interior walls of 1.5-mL polypropylene microfuge tubes. Surfactant phospholipids were added to the tubes followed by slow rotation at 37°C overnight. The liquid was decanted and spectrophotometrically analyzed at 650 nm to detect solution turbidity due to vernix detachment and/or emulsification. Increasing concentrations of surfactant phospholipids produced a dose-dependent increase in solution turbidity. A phospholipid mixture closely approximating natural pulmonary surfactant but devoid of surfactant-associated proteins yielded no increase. In other studies, the flow properties of vernix were studied in a Haake flow rheometer at 23°C and 37°C. There was a marked temperature-dependent effect with lower stress required to elicit flow at 37°C compared with 23°C. This temperature dependence was also demonstrated in the turbidity assay with a 124% increase in turbidity at body temperature compared with room temperature. We conclude that under in vitro conditions, pulmonary surfactant interacts with vernix resulting in detachment from a solid phase support. We speculate that in utero, this phenomenon contributes to the increase in amniotic fluid turbidity that is observed near term.

Effect of prenatal steroids on skin surface hydrophobicity in the premature rat.

ABSTRACT: The skin surface of the newborn rat at term is highly hydrophobic. This surface hydrophobicity plays a putative role in the transition from an aqueous to a gaseous environment at birth and is dependent on the presence of an intact periderm. Glucocorticoids given to pregnant dams, during late gestation, will accelerate formation of the stratum corneum and reduce transepidermal water loss in prematurely delivered pups. We tested the related hypotheses that surface hydrophobicity and maturation of the periderm are developmentally accelerated by prenatal exposure to steroids. Thirty pregnant Sprague-Dawley rats received either normal saline or 0.5 mg/kg betamethasone on d 17 of gestation. After cesarean delivery on d 18, 19, and 20, dorsal skin surface hydrophobicity was quantified by direct surface electrical capacitance (SEC) measurement. Initial skin surface hydration at birth was significantly lower in steroid-treated pups than in control pups at gestational ages 19 and 20 d (3060 pm 1379 versus 4441 ± 153 pF and 646 ± 295 versus 1493 ± 1019 pF, respectively, p < 0.001, mean ± SD). Likewise, after desorption of amniotic fluid, baseline skin hydration was significantly lower in steroid-treated pups than in control pups at gestational ages 19 and 20 d (1862 ± 1560 pF versus 4278 ± 97 pF and 60 ± 56 pF versus 128 ± 264 pF, p< 0.001). Scanning and transmission electron microscopy showed morphologic maturation of the periderm after steroid treatment. These results demonstrate accelerated development of both functional and structural correlates of skin surface hydrophobicity in the premature rat after prenatal exposure to steroids.

Effect of tactile stimulation on serum lactate in the newborn rat

Maturation of the CNS in neonatal animals is dependent upon both sensory input and the constant availability of metabolic fuel. Previous reports indicate that the preferred metabolic substrate for the developing rat brain is lactate. In this study, we used the neonatal Sprague-Dawley rat to investigate a possible interactive role between touch and the regulation of serum lactate. Two hundred and fifty rats (postnatal d 0-7) were exposed to a standard tactile stimulation (TS) regimen to mimic nonspecific maternal stimulation. This regimen consisted of stroking the dorsum with a soft camel hair brush for 30 s every minute for 10 min. Serum lactate and glucose levels were measured after TS. In newborn (d 0) rats, lactate levels were increased by 207% in stroked pups versus controls. This elevation of serum lactate persisted for 30 min after cessation of TS. On d 7, TS increased lactate only 11%. Glucose levels were unaffected at all ages. In neonatal pups, pretreatment with pentobarbital blocked the effect of TS, whereas epidermal growth factor evoked a synergistic response. Capsaicin pretreatment had no effect. Mixed arteriovenous blood gases revealed a mild increase in pH and a decrease in Pco2 after TS. We conclude that TS in newborn rats is a regulator of circulating lactate. This response is maximal in the immediate postnatal period and wanes over the 1st wk of life. We speculate that the transduction of sensory signals by the skin is a mechanism regulating the availability of cerebral energy substrates in the newborn mammal.

Structural Proteins in Perinatal Rat Epidermis: Characterization of a High Molecular Weight Prekeratin

ABSTRACT: The major water-insoluble proteins of perinatal rat epidermis have been examined by gel electrophoretic techniques. Particular focus has been placed on that family of epidermal structural proteins called keratins which are characterized by mol wt between 40 and 70 kD. Analysis of these proteins by 2-dimensional PAGE revealed the largest member of this family (Mr=63 kD) to consist of a series of isoelectric variants with isoelectric points ranging between 7.3 and 5.9. Antibodies raised in rabbits against this protein were specific by immunoblot analysis and exhibited no cross-reactivity with keratins isolated from human foreskin epidermis under the same extraction conditions. Ontogenetic examination by Western blot was performed on extracts of whole fetal rat skin from d 17 to d 19 of gestation. Expression of the protein was seen only after the 18th gestational d. Posttranslational modification of neonatal rat keratins by phosphorylation was examined under in vitro conditions at two different ambient temperatures (23 and 37°C). Overall phosphorylation was markedly increased at the higher temperature. A similar qualitative pattern of keratin phosphorylation was seen after in vivo labeling at nest temperature (35°C). In both the in vitro and in vivo experiments, the major radiolabeled moiety was the 63 kD epidermal protein. In summary, insoluble proteins between 40 and 70 kD have been examined in perinatal rat epidermis. The tissue localization, solubility, phosphorylation status, ontogenetic appearance, and mol wt of the 63 kD protein are consistent with the identification of an epidermal prekeratin. We hypothesize that this protein is an important molecular precursor of stratum corneum formation in the perinatal rat.

Morphological Characterization of Human Vernix: Analysis of Water Content and Comparison to Native Stratum Corneum

Morphological Characterization of Human Vernix: Analysis of Water Content and Comparison to Native Stratum Corneum

Characterization of Vernix Caseosa as a Natural Biofilm: Hydration Effects and Comparison to Aquaphor®

Characterization of Vernix Caseosa as a Natural Biofilm: Hydration Effects and Comparison to Aquaphor®

Contents Vol. 24, 2011

N. Ahmad, Madison, Wisc. P. Altmeyer, Bochum C. Antoniou, Athens H. Bachelez, Paris J.M. Baron, Aachen E. Benfeldt, Roskilde E. Berardesca, Rome D.R. Bickers, New York, N.Y. I. Bogdan Allemann, Zürich K. De Paepe, Brussels P. Elsner, Jena A. Farkas, Szeged A. Giannetti, Modena M.W. Greaves, London R.H. Guy, Bath J. Hadgraft , London E.M. Jackson, Bonney Lake, Wash. Y. Kawakubo, Chiba H.-C. Korting, Munich J. Krutmann, Düsseldorf R. Neubert, Halle D.R. Roop, Aurora, Colo. T. Ruzicka, Munich M. Schäfer-Korting, Berlin S. Seidenari, Modena J. Wohlrab, Halle S. Yamamoto, Hiroshima Journal of Pharmacological and Biophysical Research

CHANGES IN STRATUM CORNEUM-WATER INTERACTIONS FOLLOWING BIRTH IN THE NEWBORN INFANT |[bull]| 1021

The outermost layer of the skin, the stratum corneum (SC), is a thin, flexible, polymeric envelope required for survival in a terrestrial environment. Evidence from newborn animals demonstrates that the SC manifests a range of unique water interactions at birth including a hydrophobic surface mantle, integral barrier lipid lamellae, and spontaneous proteolysis of structural proteins, such as filaggrin, to form smaller water binding molecules necessary for polymer plasticization. In the present study, we evaluated the background of these interactions by quantifying changes in SC hydration, water flux, and surface hydrophobicity (water desorption) over the first 16h of life in 86 term infants. Unit measurement of surface electrical capacitive reactance (cru) served as the primary index of hydration state(Pediatrics 96:688-692, 1995). A separate study looking at the effect of occlusion was also performed using a plastic thermal wrap to occlude the lower body after birth. The results demonstrate 1) a progressive fall in surface hydration from 2h to 16 h after birth (113±3 to 105±5 crus, respectively, p < 0.05), 2) a decrease in transepidermal water movement measured as the slope of the continuous capacitance curves(0.96±0.12 at 2h of age to 0.32±0.09 crus/sec at 16h, p < 0.01), 3) an increase in surface water desorption (-7±0.6 at 2h of age to -12±1 crus/sec × 1000 at 16h, p < 0.01); 4) higher baseline hydration following occlusion of the suprapubic region at 2h of age compared to the chest (135±7 to 120±4 crus, respectively, p<0.01); and 5) increased transepidermal water movement following occlusion(2.86±0.34 compared to 1.21±0.16 crus/sec, p<0.01).

EFFECTS OF SPACEFLIGHT AND RE-ADAPTATION ON EPIDERMAL BARRIER DEVELOPMENT IN THE FETAL RAT. † 383

EFFECTS OF SPACEFLIGHT AND RE-ADAPTATION ON EPIDERMAL BARRIER DEVELOPMENT IN THE FETAL RAT. † 383