Vernix Caseosa
Definition
Vernix caseosa, also known as vernix
Is the waxy or cheese-like white substance found coating the skin of newborn babies.
Produced by dedicated cells that have some protective roles during fetal development and for a few hours after birth.
Composition
Composed of sebum,
Cells that have sloughed off the fetus's skin and shed lanugo hair.
Branched chain fatty acids, cholesterol, and ceramide.
Lipid fractions
Aminoacids
Vernix of term infants has more squalene and a higher ratio of - wax ester : sterol ester than preterm infants.
Morphology
Cells of vernix are polygonal or ovoid in shape and lack nuclei.
Nuclear ghosts are frequently observed.
Vernix corneocytes lack desmosomal attachment and this distinguishes them from corneocytes found in mature stratum corneum.
These cells are surrounded by a layer of amorphous lipids lacking typical lamellar architecture present in mature stratum corneum.
Physical properties
Vernix is not uniformly distributed
Present in form of cellular sponges.
The critical surface tension of vernix is 39 dyne/cm.
Despite its water content (82%), vernix is nonpolar. Hence the "waterproofing" function of vernix, thereby preventing heat loss soon after birth
Biological properties
Vernix provides electrical isolation for the fetus, an important aspect of developing fetal anatomy.
Washing skin surface after birth reduces evaporative water losses compared to surface of newborns in which vernix is left in situ.
Vernix is hydrophobic.
Vernix assists in the development of the human intestinal microbiota.
Secretion
The sebum in vernix is produced in utero by the sebaceous glands around the 20th week of gestation.
Vernix appears primarily in full term infants, while premature and postmature births generally do not display any.
Postdates desquamation (flakey skin in babies born >42 weeks) is thought to be due to loss of vernix.
Functions
Moisturizing the infant's skin, and facilitating passage through the birth canal.
Conserve heat and protect the delicate newborn skin from environmental stress.
Antibacterial effect.
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