Vernix caseosa: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Add another good source. All 3 papers are old.
fECG; polar comp.
Line 14: Line 14:


===Composition===
===Composition===
Vernix has a highly variable makeup but is primarily composed of [[sebum]], cells that have sloughed off the fetus's skin and shed [[lanugo]] hair.<ref name = Schachner2003>{{cite book |first1=Lawrence A. |last1=Schachner |first2=Ronald C. |last2=Hansen |title=Pediatric dermatology |publisher=Mosby |location=St. Louis |year=2003 |isbn=978-0-323-02611-6 |pages=206–7}}</ref> Chemically, it is water (80%), [[Lipid|lipids]] (10%) and [[Protein|proteins]] (10%).<ref name=":0" /> The lipids include [[Ceramide|ceramides]], [[cholesterol]], [[Fatty acid|fatty acids]], [[Triglyceride|triglycerides]], [[Wax ester|waxes]] and [[Sterol ester|sterol esters]], [[squalene]], and [[Phospholipid|phospholipids]].<ref name=":0" /> The protein composition is relatively understudied.<ref name=":0" /> Vernix of term infants has more [[squalene]] and a higher [[wax ester]] to [[sterol ester]] ratio than preterm infants.<ref name="Schachner2003" />
Vernix has a highly variable makeup but is primarily composed of [[sebum]], cells that have sloughed off the fetus's skin and shed [[lanugo]] hair.<ref name = Schachner2003>{{cite book |first1=Lawrence A. |last1=Schachner |first2=Ronald C. |last2=Hansen |title=Pediatric dermatology |publisher=Mosby |location=St. Louis |year=2003 |isbn=978-0-323-02611-6 |pages=206–7}}</ref> Chemically, it is water (80%), [[Lipid|lipids]] (10%) and [[Protein|proteins]] (10%).<ref name=":0" /> The lipids include [[Ceramide|ceramides]], [[cholesterol]], [[Fatty acid|fatty acids]], [[Triglyceride|triglycerides]], [[Wax ester|waxes]] and [[Sterol ester|sterol esters]], [[squalene]], and [[Phospholipid|phospholipids]]<ref name=":0" />; multiple detailed analyses of the polar components have been done.<ref>{{Cite journal|last=Harazim|first=Eva|last2=Vrkoslav|first2=Vladimír|last3=Buděšínský|first3=Miloš|last4=Harazim|first4=Petr|last5=Svoboda|first5=Martin|last6=Plavka|first6=Richard|last7=Bosáková|first7=Zuzana|last8=Cvačka|first8=Josef|date=2018-11-01|title=Nonhydroxylated 1-O-acylceramides in vernix caseosa|url=http://www.jlr.org/content/59/11/2164|journal=Journal of Lipid Research|language=en|volume=59|issue=11|pages=2164–2173|doi=10.1194/jlr.M088864|issn=0022-2275|pmid=30254076}}</ref> The protein composition is relatively understudied.<ref name=":0" /> Vernix of term infants has more [[squalene]] and a higher [[wax ester]] to [[sterol ester]] ratio than preterm infants.<ref name="Schachner2003" />


===Morphology===
===Morphology===
Line 24: Line 24:
Vernix is a white viscous cream-like substance in appearance.<ref name=":0" />
Vernix is a white viscous cream-like substance in appearance.<ref name=":0" />


The water is not uniformly distributed throughout, but rather exclusively present in the sponge-like corneocytes; despite its high water content, vernix is nonpolar (due to lipids) and more vapor-permeable than strateum corneum.<ref name=":0" /><ref name="nskin">{{cite book|last=Hoath|first=Steven|url=https://archive.org/details/neonatalskin00hoat|title=Neonatal skin : structure and function|publisher=Dekker|year=2003|isbn=0-8247-0887-3|edition=2. ed., rev. and expanded.|location=New York [u.a.]|pages=[https://archive.org/details/neonatalskin00hoat/page/n205 193]–208|url-access=limited}}</ref>
The water is not uniformly distributed throughout, but rather exclusively present in the sponge-like corneocytes; despite its high water content, vernix is nonpolar (due to lipids) and more vapor-permeable than strateum corneum.<ref name=":0" /><ref name="nskin">{{cite book|last=Hoath|first=Steven|url=https://archive.org/details/neonatalskin00hoat|title=Neonatal skin : structure and function|publisher=Dekker|year=2003|isbn=0-8247-0887-3|edition=2. ed., rev. and expanded.|location=New York [u.a.]|pages=[https://archive.org/details/neonatalskin00hoat/page/n205 193]–208|url-access=limited}}</ref><ref>{{Cite journal|last=Visscher|first=Marty|last2=Narendran|first2=Vivek|date=2013-09-25|title=The Ontogeny of Skin|url=https://www.liebertpub.com/doi/10.1089/wound.2013.0467|journal=Advances in Wound Care|volume=3|issue=4|pages=291–303|doi=10.1089/wound.2013.0467|issn=2162-1918|pmc=PMC3985523|pmid=24761361}}</ref>


==Functions==
==Functions==
Line 31: Line 31:
It is theorized (and observed) to serve several purposes:<ref name=":0" /><ref name=":1">{{Cite journal|last=Singh|first=Gurcharan|last2=Archana|first2=G|date=2008|title=UNRAVELING THE MYSTERY OF VERNIX CASEOSA|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763724/|journal=Indian Journal of Dermatology|volume=53|issue=2|pages=54–60|doi=10.4103/0019-5154.41645|issn=0019-5154|pmc=2763724|pmid=19881987}}</ref><ref name="nskin" />
It is theorized (and observed) to serve several purposes:<ref name=":0" /><ref name=":1">{{Cite journal|last=Singh|first=Gurcharan|last2=Archana|first2=G|date=2008|title=UNRAVELING THE MYSTERY OF VERNIX CASEOSA|url=https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2763724/|journal=Indian Journal of Dermatology|volume=53|issue=2|pages=54–60|doi=10.4103/0019-5154.41645|issn=0019-5154|pmc=2763724|pmid=19881987}}</ref><ref name="nskin" />


* Electrical isolation of the fetus (this affects accurate fECG measurement of fetal heartbeat).<ref>{{Cite journal|last=Chiera|first=Marco|last2=Cerritelli|first2=Francesco|last3=Casini|first3=Alessandro|last4=Barsotti|first4=Nicola|last5=Boschiero|first5=Dario|last6=Cavigioli|first6=Francesco|last7=Corti|first7=Carla G.|last8=Manzotti|first8=Andrea|date=2020|title=Heart Rate Variability in the Perinatal Period: A Critical and Conceptual Review|url=https://www.frontiersin.org/articles/10.3389/fnins.2020.561186/full|journal=Frontiers in Neuroscience|language=English|volume=14|doi=10.3389/fnins.2020.561186|issn=1662-453X}}</ref>
* Electrical isolation of the fetus.
* Waterproofing the skin, whilst in gestation.
* Waterproofing the skin, whilst in gestation.
* Lubricating the infant's skin, and facilitating easy passage through the [[Vagina|birth canal]].
* Lubricating the infant's skin, and facilitating easy passage through the [[Vagina|birth canal]].
*Preventing infections — primarily as a mechanical barrier and secondarily via the presence of [[lysozyme]], [[lactoferrin]] and antimicrobial components in peptide layer.
*Preventing infections — primarily as a mechanical barrier and secondarily via the presence of [[lysozyme]], [[lactoferrin]] and antimicrobial components in peptide layer.
*Moisturizing the [[stratum corneum]] whilst in gestation (and controlled drying in post-partum phase).
*Moisturizing the [[stratum corneum]] whilst in gestation (and controlled drying in [[Postpartum period|post-partum]] phase).
* [[Thermoregulation]] in post-partum phase — evidence is mixed.
* [[Thermoregulation]] in post-partum phase — evidence is mixed.
*Quick healing of epidermal wounds.
*Quick healing of epidermal wounds.

Revision as of 10:26, 4 January 2021

Baby held in a gloved hand, with creamy substance smeared all over
Newborn baby immediately after birth, covered in vernix

Vernix caseosa, also known as vernix, is the waxy white substance found coating the skin of newborn human babies.[1] It is produced by dedicated cells and is thought to have some protective roles during fetal development and for a few hours after birth.

Etymology

In Latin, vernix means varnish and caseosa means cheesy. The term was first published in 1846 in the Dunglison Dictionary of Medical Sciences.[1]

In-utero development

Vernix is secreted during a distinct phase of the epidermal development.[2] By the 21st week of gestation, periderm cells have been shed and replaced with strateum corneum; these shedding then mix with secretions of sebum by the sebaceous glands to form vernix, which gradually covers the body in an anteroposterior and dorsoventral pattern.[1][2]

By early third trimester, vernix is emulsified by increasing concentrations of pulmonary surfactants and desiccates (only to be subsequently consumed by the fetus); a corresponding increase in amniotic fluid turbidity is noticed.[2]

Characteristics

Composition

Vernix has a highly variable makeup but is primarily composed of sebum, cells that have sloughed off the fetus's skin and shed lanugo hair.[3] Chemically, it is water (80%), lipids (10%) and proteins (10%).[1] The lipids include ceramides, cholesterol, fatty acids, triglycerides, waxes and sterol esters, squalene, and phospholipids[1]; multiple detailed analyses of the polar components have been done.[4] The protein composition is relatively understudied.[1] Vernix of term infants has more squalene and a higher wax ester to sterol ester ratio than preterm infants.[3]

Morphology

Vernix is composed of mobile corneocytes embedded in an amorphous lipid matrix.[1] Precise biological mechanisms leading to its formation are hazily known.[5]

The cells are polygonal or ovoid in shape, malleable, and lack nuclei; typical thickness is 1-2 µm.[1] Nuclear ghosts are frequently observed and Acid Phosphatase Activity is nonuniform.[1] Keratin filaments build a scaffold like structure which form a water-storage area.[1] As opposed to stratum corneum, the vernix corneocytes lack desmosomal attachment and the lipid layer is more disordered.[6]

Physical properties

Vernix is a white viscous cream-like substance in appearance.[1]

The water is not uniformly distributed throughout, but rather exclusively present in the sponge-like corneocytes; despite its high water content, vernix is nonpolar (due to lipids) and more vapor-permeable than strateum corneum.[1][7][8]

Functions

Vernix appears in all full term infants but with widely varying body-coverage, while premature and post-mature births generally do not display any.[3][2]

It is theorized (and observed) to serve several purposes:[1][2][7]

  • Electrical isolation of the fetus (this affects accurate fECG measurement of fetal heartbeat).[9]
  • Waterproofing the skin, whilst in gestation.
  • Lubricating the infant's skin, and facilitating easy passage through the birth canal.
  • Preventing infections — primarily as a mechanical barrier and secondarily via the presence of lysozyme, lactoferrin and antimicrobial components in peptide layer.
  • Moisturizing the stratum corneum whilst in gestation (and controlled drying in post-partum phase).
  • Thermoregulation in post-partum phase — evidence is mixed.
  • Quick healing of epidermal wounds.
  • Development of gut, after intra-uterine consumption.

Medical uses

Vernix is used as a reliable site-of-record for measuring cocaine exposure in pregnant women.[2] Using vernix for diagnosing uterine rupture and amniotic fluid embolism has been proposed.[2]

Disorders

Granuloma and peritonitis of vernix have been observed in Caesarean sections.[2] High volumes of vernix cause Neonatal Aspiration Syndrome.[2]

Other species

Vernix is thought to be unique to human fetal development; in 2018, vernix-like material was reportedly obtained from pups of Zalophus californianus.[10]

Additional images

  • Vernix on a newborn's legs and feet.
    Vernix on a newborn's legs and feet.
  • Traces of vernix caseosa on a full term newborn.
    Traces of vernix caseosa on a full term newborn.
  • Closeup of baby's face right after birth, skin covered in vernix and some blood.
    Closeup of baby's face right after birth, skin covered in vernix and some blood.

References

  1. ^ a b c d e f g h i j k l m Nishijima, Koji; Yoneda, Makoto; Hirai, Takayoshi; Takakuwa, Koichi; Enomoto, Takayuki (2019). "Biology of the vernix caseosa: A review". Journal of Obstetrics and Gynaecology Research. 45 (11): 2145–2149. doi:10.1111/jog.14103. ISSN 1447-0756.
  2. ^ a b c d e f g h i Singh, Gurcharan; Archana, G (2008). "UNRAVELING THE MYSTERY OF VERNIX CASEOSA". Indian Journal of Dermatology. 53 (2): 54–60. doi:10.4103/0019-5154.41645. ISSN 0019-5154. PMC 2763724. PMID 19881987.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  3. ^ a b c Schachner, Lawrence A.; Hansen, Ronald C. (2003). Pediatric dermatology. St. Louis: Mosby. pp. 206–7. ISBN 978-0-323-02611-6.
  4. ^ Harazim, Eva; Vrkoslav, Vladimír; Buděšínský, Miloš; Harazim, Petr; Svoboda, Martin; Plavka, Richard; Bosáková, Zuzana; Cvačka, Josef (2018-11-01). "Nonhydroxylated 1-O-acylceramides in vernix caseosa". Journal of Lipid Research. 59 (11): 2164–2173. doi:10.1194/jlr.M088864. ISSN 0022-2275. PMID 30254076.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  5. ^ Hoath, Steven B.; Narendran, Vivek; Visscher, Marty O. (2011), "Vernix Caseosa and Innate Immunity", Innate Immune System of Skin and Oral Mucosa, John Wiley & Sons, Ltd, pp. 145–169, doi:10.1002/9781118025338.ch8, ISBN 978-1-118-02533-8, retrieved 2021-01-04
  6. ^ Rissmann, Robert; Groenink, Hendrik W.W.; Weerheim, Arij M.; Hoath, Steven B.; Ponec, Maria; Bouwstra, Joke A. (August 2006). "New Insights into Ultrastructure, Lipid Composition and Organization of Vernix Caseosa". Journal of Investigative Dermatology. 126 (8): 1823–1833. doi:10.1038/sj.jid.5700305. ISSN 0022-202X.
  7. ^ a b Hoath, Steven (2003). Neonatal skin : structure and function (2. ed., rev. and expanded. ed.). New York [u.a.]: Dekker. pp. 193–208. ISBN 0-8247-0887-3.
  8. ^ Visscher, Marty; Narendran, Vivek (2013-09-25). "The Ontogeny of Skin". Advances in Wound Care. 3 (4): 291–303. doi:10.1089/wound.2013.0467. ISSN 2162-1918. PMC 3985523. PMID 24761361.{{cite journal}}: CS1 maint: PMC format (link)
  9. ^ Chiera, Marco; Cerritelli, Francesco; Casini, Alessandro; Barsotti, Nicola; Boschiero, Dario; Cavigioli, Francesco; Corti, Carla G.; Manzotti, Andrea (2020). "Heart Rate Variability in the Perinatal Period: A Critical and Conceptual Review". Frontiers in Neuroscience. 14. doi:10.3389/fnins.2020.561186. ISSN 1662-453X.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  10. ^ Brenna, Tom (May 10, 2018). "Sea Lions Develop Human-like Vernix Caseosa Delivering Branched Fats and Squalene to the GI Tract". Scientific Reports. 8 (7478): 7478. Bibcode:2018NatSR...8.7478W. doi:10.1038/s41598-018-25871-1. PMC 5945841. PMID 29748625.

Wikimedia Commons

Wikimedia Commons has media related to Vernix caseosa.
Retrieved from "https://en.wikipedia.org/w/index.php?title=Vernix_caseosa&oldid=998220156"