Characterization of Vernix Caseosa: Water Content, Morphology, and Elemental Analysis

Abstract

Recent studies have prompted interest in the use of epidermal barrier creams as protective biofilms for very low birthweight preterm infants. The key to understanding the role of epidermal barrier films is an elucidation of their interaction with water and a basic knowledge of their composition. In this study, we investigated the morphologic properties and elemental composition of the naturally occurring biofilm, vernix caseosa. This biofilm is typically lacking in preterm infants and its production coincides in utero with terminal differentiation of the epidermis and formation of the stratum corneum. Significantly, vernix (80.5+/-1.0% H2O) had a much higher water content than other barrier creams (Eucerin: 17.1+/-0.6%, Aquaphor: 0.33+/-0.03%, Ilex: 0.19+/-0.02%, petrolatum: 0.03+/-0.01%; all p<0.05). Phase contrast microscopy of vernix showed multiple cellular elements with nucleic "ghosts" embedded in a putative lipid matrix. Transmission electron microscopy revealed flattened structures approximately 1-2 microm in thickness with distinct cellular envelopes indicative of differentiated corneocytes. Compared with mature corneocytes in adult stratum corneum, vernix corneocytes appeared swollen, the density of the keratin filaments was less, and there was a relative lack of tonofilament orientation. Cryofractured specimens were examined by cryoscanning electron microscopy with subsequent elemental localization by X-ray beam analysis. The findings indicate the high water content of vernix is largely compartmentalized within fetal corneocytes. These results are consistent with the novel view of vernix as a "fluid phase" stratum corneum consisting of a hydrophobic lipid matrix with embedded fetal corneocytes possessing unique biomechanical and water-binding properties.

Effect of Vernix Caseosa on the Penetration of Chymotryptic Enzyme: Potential Role in Epidermal Barrier Development

“…Vernix caseosa is a viscous, whitish substance coating the fetal skin surface during the last trimester. Morphologically, Agorastos et al (3) reported a cellular component of vernix, a finding confirmed and extended by our laboratory (4). Electron micrographs show the presence of fetal corneocytes surrounded by unstructured vernix lipid.…”

“…By composition, vernix is mainly composed of water (80%), lipid (10.3%), and protein (9.1%) (2). It consists of a lipid matrix containing detached corneocytes derived from possible remnants of the epitrichium, the differentiating fetal epidermis, and the pilosebaceous unit (3,4). Vernix lipid is, thus, composed of two types of lipid: sebaceous lipid and stratum corneum lipid (5)(6)(7)(8).…”

Vernix Caseosa in Neonatal Adaptation

“…Vernix loses its exogenous water slowly. 13 Application of vernix to adult volar forearm skin resulted in an increased capacity to bind exogenous water. 14 Vernix may also function to maintain skin hydration at birth and potentially facilitates formation of the acid mantle of the skin.…”

Skin Care in Young Children: Innovative Approaches

“…3). Она состоит из секрета сальных желез, лануго и эпители-альных клеток, которые покрывают кожу плода [11]. В целом это комплекс представляет собой смесь, состоя-щую из 80% воды, 10% белка и 10% липидов, а именно плотно прилегающих друг к другу корнеоцитов, которые покрыты аморфным липидным матриксом [12,13].…”