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| * '''Skin barrier in the neonate'''{{#pmid:29596733|PMID29596733}} "The purpose of this review is to focus on determinants of skin barrier function in neonates at molecular and cellular levels. The skin barrier is critical in terms of water and gas exchanges during fetal life and undergoes rapid changes at birth, followed by a progressive maturation. Consequences of skin barrier disruption can be extremely detrimental or lethal, as shown in severe genetic epidermal defects. In this context, the fine-tuned rapid adaptation from a liquid to a gaseous milieu is not fully understood. The stratum corneum provides an air-liquid barrier, tight junctions in the granular layer provide a liquid-liquid barrier, aquaporins represent a plumbing system for water-glycerol as well as gas exchanges, and Langerhans cells are central to the immunological barrier. Acid mantle formation is essential for appropriate interaction between the skin and microbial symbionts. Temperature and pH regulate the key enzyme activities responsible for the integrity of the stratum corneum. Skin barrier permeability can be assessed noninvasively and simply with miniaturized devices measuring transepidermal water loss, where water flow is faster in cases of a damaged or functionally premature barrier. New avenues for therapeutic skin barrier research in neonates include a better delineation of the maturation of aquaporins in water balance and gas exchanges from fetal to neonatal life and a better understanding of the role of vernix caseosa, in particular, for the implantation of a healthy microbiote. Practical applications should be derived for caring for infant skin, particularly in fragile zones, such as the diaper area." {{neonatal}} | | * '''Skin barrier in the neonate'''{{#pmid:29596733|PMID29596733}} "The purpose of this review is to focus on determinants of skin barrier function in neonates at molecular and cellular levels. The skin barrier is critical in terms of water and gas exchanges during fetal life and undergoes rapid changes at birth, followed by a progressive maturation. Consequences of skin barrier disruption can be extremely detrimental or lethal, as shown in severe genetic epidermal defects. In this context, the fine-tuned rapid adaptation from a liquid to a gaseous milieu is not fully understood. The stratum corneum provides an air-liquid barrier, tight junctions in the granular layer provide a liquid-liquid barrier, aquaporins represent a plumbing system for water-glycerol as well as gas exchanges, and Langerhans cells are central to the immunological barrier. Acid mantle formation is essential for appropriate interaction between the skin and microbial symbionts. Temperature and pH regulate the key enzyme activities responsible for the integrity of the stratum corneum. Skin barrier permeability can be assessed noninvasively and simply with miniaturized devices measuring transepidermal water loss, where water flow is faster in cases of a damaged or functionally premature barrier. New avenues for therapeutic skin barrier research in neonates include a better delineation of the maturation of aquaporins in water balance and gas exchanges from fetal to neonatal life and a better understanding of the role of vernix caseosa, in particular, for the implantation of a healthy microbiote. Practical applications should be derived for caring for infant skin, particularly in fragile zones, such as the diaper area." {{neonatal}} |
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| | * '''Newborn boys and girls differ in the lipid composition of vernix caseosa'''{{#pmid:24911066|PMID24911066}} "Vernix caseosa protects the skin of a human fetus during the last trimester of pregnancy and of a newborn after the delivery. Besides its cellular and proteinaceous components, an important constituent and functional agent is a complex lipid fraction, implicated in a multitude of salubrious effects of vernix caseosa. Little is known about how the chemical composition of vernix caseosa lipids is affected by various biological characteristics of the baby, such as the gestational age, birth weight, and, last but not least, the gender of the newborn. This study reports on the chemical variability of lipids contained in the vernix caseosa of twenty newborn girls and boys and shows that the quantitative patterns of the lipids are sex-specific. The specificity of lipids was investigated at the level of fatty acids in the total lipid extracts and intact lipids of several neutral lipid classes. Hydrocarbons, wax esters, cholesteryl esters, diol diesters and triacylglycerols were isolated using optimized semipreparative thin-layer chromatography, and the molecular species within each class were characterized using matrix-assisted laser desorption/ionization mass spectrometry. Statistical evaluation revealed significant quantitative sex-related differences in the lipid composition of vernix caseosa among the newborns, pronounced in the two lipid classes associated with the activity of sebaceous glands. Higher proportions of wax esters and triacylglycerols with longer hydrocarbon chains were observed in newborn girls." |
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Revision as of 11:00, 9 August 2018
Introduction
The vernix caseosa has several different potential functions and a variable composition.[1]
- a highly variable coating of the fetal skin
- high water content (80%) largely compartmentalized within fetal corneocytes (cells forming the stratum corneum)
- develops cranio-caudally production coincides in utero with terminal differentiation of the epidermis and formation of the stratum corneum
- primarily composed of sebum, cells that have sloughed off the fetus's skin and shed lanugo hair
- can be absent in preterm infants
- dehydration and rehydration processes occur two to four times faster at 37 degrees celcius than at room temperature[2]
- towards term fragments of vernix can mix into the amniotic fluid resulting in (normal) turbidity
- fetal swallowing of amniotic fluid mixed with fragments of vernix can also occur
- cathelicidin LL-37, alpha-defensins, and LL-37 in neutrophils.[3]
Some Recent Findings
- Skin barrier in the neonate[4] "The purpose of this review is to focus on determinants of skin barrier function in neonates at molecular and cellular levels. The skin barrier is critical in terms of water and gas exchanges during fetal life and undergoes rapid changes at birth, followed by a progressive maturation. Consequences of skin barrier disruption can be extremely detrimental or lethal, as shown in severe genetic epidermal defects. In this context, the fine-tuned rapid adaptation from a liquid to a gaseous milieu is not fully understood. The stratum corneum provides an air-liquid barrier, tight junctions in the granular layer provide a liquid-liquid barrier, aquaporins represent a plumbing system for water-glycerol as well as gas exchanges, and Langerhans cells are central to the immunological barrier. Acid mantle formation is essential for appropriate interaction between the skin and microbial symbionts. Temperature and pH regulate the key enzyme activities responsible for the integrity of the stratum corneum. Skin barrier permeability can be assessed noninvasively and simply with miniaturized devices measuring transepidermal water loss, where water flow is faster in cases of a damaged or functionally premature barrier. New avenues for therapeutic skin barrier research in neonates include a better delineation of the maturation of aquaporins in water balance and gas exchanges from fetal to neonatal life and a better understanding of the role of vernix caseosa, in particular, for the implantation of a healthy microbiote. Practical applications should be derived for caring for infant skin, particularly in fragile zones, such as the diaper area." neonatal
- Newborn boys and girls differ in the lipid composition of vernix caseosa[5] "Vernix caseosa protects the skin of a human fetus during the last trimester of pregnancy and of a newborn after the delivery. Besides its cellular and proteinaceous components, an important constituent and functional agent is a complex lipid fraction, implicated in a multitude of salubrious effects of vernix caseosa. Little is known about how the chemical composition of vernix caseosa lipids is affected by various biological characteristics of the baby, such as the gestational age, birth weight, and, last but not least, the gender of the newborn. This study reports on the chemical variability of lipids contained in the vernix caseosa of twenty newborn girls and boys and shows that the quantitative patterns of the lipids are sex-specific. The specificity of lipids was investigated at the level of fatty acids in the total lipid extracts and intact lipids of several neutral lipid classes. Hydrocarbons, wax esters, cholesteryl esters, diol diesters and triacylglycerols were isolated using optimized semipreparative thin-layer chromatography, and the molecular species within each class were characterized using matrix-assisted laser desorption/ionization mass spectrometry. Statistical evaluation revealed significant quantitative sex-related differences in the lipid composition of vernix caseosa among the newborns, pronounced in the two lipid classes associated with the activity of sebaceous glands. Higher proportions of wax esters and triacylglycerols with longer hydrocarbon chains were observed in newborn girls."
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| More recent papers
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More? References | Discussion Page | Journal Searches | 2019 References | 2020 References
Search term: Vernix Caseosa
<pubmed limit=5>Vernix Caseosa</pubmed>
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Textbooks
- Human Embryology (2nd ed.) Larson Chapter 14 p443-455
- The Developing Human: Clinically Oriented Embryology (6th ed.) Moore and Persaud Chapter 20: P513-529
- Before We Are Born (5th ed.) Moore and Persaud Chapter 21: P481-496
- Essentials of Human Embryology Larson Chapter 14: P303-315
- Human Embryology, Fitzgerald and Fitzgerald
- Color Atlas of Clinical Embryology Moore Persaud and Shiota Chapter 15: p231-236
Integumentary Development Overview
4 weeks
- simple ectoderm epithelium over mesenchyme.
1-3 months
- ectoderm - germinative (basal) cell repeated division of generates stratified epithelium.
- mesoderm - differentiates into connective tissue and blood vessels.
- week 11 - (GA week 13) blood vessels visible in the early fetal skin, small blood vessels in the upper papillary region and larger vessels in the deep reticular dermis.[7]
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Integument Human Embryo (Week 8, Stage 22)
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4 months
Fetal human integumentary histology[7](Weeks in figure are from LMP)
- Basal cell - proliferation generates folds in basement membrane.
- Neural crest cells - melanoblasts migrate into epithelium. These are the future melanocyte pigment cell of the skin.
- Embryonic connective tissue- differentiates into dermis, a loose ct layer over a dense ct layer. Beneath the dense ct layer is another loose ct layer that will form the subcutaneous layer.
- Ectoderm contributes to nails, hair follictles and glands.
- Nails form as thickening of ectoderm epidermis at the tips of fingers and toes. These form germinative cells of nail field.
- Cords of these cells extend into mesoderm forming epithelial columns. These form hair follicles, sebaceous and sweat glands.
5 months
- Hair growth initiated at base of cord, lateral outgrowths form associated sebaceous glands.
- Other cords elongate and coil to form sweat glands.
- Cords in mammary region branch as they elongate to form mammary glands. These glands will complete development in females at puberty. Functional maturity only occurs in late pregnancy.
Embryonic and Fetal Epidermis
Electron Micrographs of the Developing Human Epidermis[8]
6 to 8 weeks (8-9 week EGA)
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7 to 9 weeks (9-11 week EGA)
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22 weeks (about 24 week EGA)
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References
- ↑ Pickens WL, Warner RR, Boissy YL, Boissy RE & Hoath SB. (2000). Characterization of vernix caseosa: water content, morphology, and elemental analysis. J. Invest. Dermatol. , 115, 875-81. PMID: 11069626 DOI.
- ↑ Rissmann R, Groenink HW, Gooris GS, Oudshoorn MH, Hennink WE, Ponec M & Bouwstra JA. (2008). Temperature-induced changes in structural and physicochemical properties of vernix caseosa. J. Invest. Dermatol. , 128, 292-9. PMID: 17671513 DOI.
- ↑ Yoshio H, Lagercrantz H, Gudmundsson GH & Agerberth B. (2004). First line of defense in early human life. Semin. Perinatol. , 28, 304-11. PMID: 15565791
- ↑ Taïeb A. (2018). Skin barrier in the neonate. Pediatr Dermatol , 35 Suppl 1, s5-s9. PMID: 29596733 DOI.
- ↑ Míková R, Vrkoslav V, Hanus R, Háková E, Hábová Z, Doležal A, Plavka R, Coufal P & Cvačka J. (2014). Newborn boys and girls differ in the lipid composition of vernix caseosa. PLoS ONE , 9, e99173. PMID: 24911066 DOI.
- ↑ Fuchs E. (2008). Skin stem cells: rising to the surface. J. Cell Biol. , 180, 273-84. PMID: 18209104 DOI.
- ↑ 7.0 7.1 Coolen NA, Schouten KC, Middelkoop E & Ulrich MM. (2010). Comparison between human fetal and adult skin. Arch. Dermatol. Res. , 302, 47-55. PMID: 19701759 DOI.
- ↑ Dale BA, Holbrook KA, Kimball JR, Hoff M & Sun TT. (1985). Expression of epidermal keratins and filaggrin during human fetal skin development. J. Cell Biol. , 101, 1257-69. PMID: 2413039
Reviews
Visscher MO, Adam R, Brink S & Odio M. (2015). Newborn infant skin: physiology, development, and care. Clin. Dermatol. , 33, 271-80. PMID: 25889127 DOI.
Singh G & Archana G. (2008). Unraveling the mystery of vernix caseosa. Indian J Dermatol , 53, 54-60. PMID: 19881987 DOI.
Articles
Kalužíková A, Vrkoslav V, Harazim E, Hoskovec M, Plavka R, Buděšínský M, Bosáková Z & Cvačka J. (2017). Cholesteryl esters of ω-(O-acyl)-hydroxy fatty acids in vernix caseosa. J. Lipid Res. , 58, 1579-1590. PMID: 28576934 DOI.
Search PubMed
Search Pubmed: Vernix Caseosa
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Additional Images
Category:Integumentary
Historic
| Historic Disclaimer - information about historic embryology pages
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| Pages where the terms "Historic" (textbooks, papers, people, recommendations) appear on this site, and sections within pages where this disclaimer appears, indicate that the content and scientific understanding are specific to the time of publication. This means that while some scientific descriptions are still accurate, the terminology and interpretation of the developmental mechanisms reflect the understanding at the time of original publication and those of the preceding periods, these terms, interpretations and recommendations may not reflect our current scientific understanding. (More? Embryology History | Historic Embryology Papers)
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Terms
| Integumentary Terms
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Integumentary Development
- acrosyringium - coiled intra-epidermal region of the eccrine gland sweat duct.
- apocrine gland - (sweat gland) proteinaceous secretion associated with hair (axilla, areola, genital and anal regions). Additional glands associated with eyelashes are called the glands of Moll (ciliary gland). (More? image - apocrine secretion)
- arrector pili muscle - bundle of smooth muscle associated with hair follicle, inserts into the papillary layer of the dermis and attaches to the dermal sheath of the hair follicle. (More? image - arrector pili muscle)
- Blaschko lines - (lines of Blaschko) may represent pathways of epidermal cell migration and proliferation during development. Specific type of lupus erythematosus shows this distinctive pattern. Named after Alfred Blaschko a German dermatologist who first described the feature in 1901. (More? PMID 21396561 | Historic Terminology)
- bulb - the hair follicle enlargement located at its deepest end, dividing cells form the hair and the root sheath.
- café-aut-lait macule - (French, cafe-au-lait = coffee with milk; birthmark) describes the characteristic colour of the skin hyperpigmented patch present at birth (congenital) or appearing in early infancy. Common single feature, multiple are associated with various genetic syndromes including Neurofibromatosis type 1 and 2.
- corneocytes - terminally differentiated keratinocytes forming the stratum corneum.
- cutis - alternative term for the epidermis and the dermis layers of the skin.
- dermal papillae - interdigitation of the dermis with the epidermis.
- dermatoglyphic patterns - (Greek, derma = "skin", glyph = "carving") fingers, palms, toes, and soles skin patterns.
- dermis - connective tissue middle layer of the skin, consists of two sublayers (papillary and reticular layers) that do not have a clear boundary. Embryologically derived from the somite dermatome.
- dermomyotome - Early embryonic dorsolateral half of the somite that will later divide to form both the dermatome and myotome. The dermatome will contribute the dermis and hypodermis of the skin. The myotome will contribute the skeletal muscle of muscoloskeletal system. Development sequence: mesoderm to paraxial mesoderm to somite to "dermomyotome" then dermatome and myotome. (More? Somitogenesis | Musculoskeletal System Development | Integumentary System Development)
- eccrine gland (Greek, ekkrinein = "secrete"; merocrine glands) sweat glands unique to some primates and used in humans for thermoregulation. Adult body has 2 to 4 million sweat glands with concentrations (700/cm) on the palms of the hand, soles of the feet and forehead. Secretion is timulated by sympathetic nervous system, post-ganglionic cholinergic branch, and other stimuli
- ephilis - (pl., ephilides; freckle) Clinical term describing a "freckle", that is a small brown or tan mark on the skin. These inherited features result from a copy of variant Melanocortin 1 Receptor (MC1R) gene and are common on fair skinned Celtic children. Melanocytes produce locally more melanin, this can also increase following exposure to ultraviolet radiation in sunlight. (More? Integumentary | Neural Crest | OMIM MC1R)
- epidermis - Histological term describing the external cellular epithelial layer of the integumentary (skin) covering the entire body. This surface layer of keratinocytes is ectoderm in origin, while the underlying connective tissue layers of dermis and hypodermis are mesoderm in origin. (More? Integumentary Development)
- epidermal differentiation complex - (EDC) human chromosome (1q2) containing linked 63 genes within four gene families that are molecular markers for stratified epidermis terminal differentiation.
- epidermal growth factor receptor - expressed on cells in the epidermis basal layer, signaling stimulates both epidermal growth and wound healing and also mediates an inhibition of differentiation.
- glabrous skin - skin without hair, refers to the palms of hands and soles of feet.
- hair - (pili) in humans consists of vellus and terminal hairs.
- holocrine - form of gland secretion where the secretory cells eventually lyse (rupture) and are lost. On the skin, these cells release sebum consisting mainly of lipid. (More? image - holocrine secretion)
- hypodermis - (subcutis, subcutaneous adipose) a connective tissue ilower layer of the skin that binds it to underlying structures.
- integumentary - term for the skin and its appendages.
- involucrin - protein that binds loricrin in the development of the cell envelope protecting corneocytes in the skin.
- keratinocyte - the main cell type forming the layers of the epidermis, derived from ectoderm.
- keratohyalin granule - found in the stratum granulosum consist of profilaggrin and loricrin.
- Langerhans cell - skin dendritic cell (antigen presenting cell) develops initially from fetal liver monocytes and yolk sac macrophages. May, depending on the immunological setting, elicit immunity or tolerance. Named after Paul Langerhans.
- Langer's lines - (skin cleavage lines, cleavage lines) Clinical term for the orientation of reticular dermis collagen bundles causing tensions on skin and subcutaneous tissues. Lines tend to be horizontal in the trunk and neck, and longitudinal in the skin and limbs. (More? PMID 15791423)
- Meissner corpuscle - sensory structure acting as a rapidly-adapting mechanoreceptor mainly in the dermal papillae of (digital) skin. (More?Touch
- melanin - (Greek, melanos = black) The pigment produced by melanocytes that provides photoprotection, preventing cellular DNA damage, and colouring of the basal epithelial cells that absorb the pigment.
- melanodermia - hyperpigmentation causing abnormal darkening (brown/black) of the skin due to excess melanin or by metallic substances. See also the abnormality ceruloderma (blue/grey). (More? PMID 23522626)
- melanocyte - (Greek, melanos = black) A pigmented cell, neural crest in origin, differentiating from melanoblasts located in the skin and other tissues that produces melanin. The melanocytes within the integument (skin) transfer melanin to keratinocytes to give skin colour and to the hair follicle to give hair colour. Melanocytes are also located within "non-cutaneous" tissues in the eye (for eye colour), harderian gland and inner ear. This is the cell type that proliferates in the cancer melanoma. (More? Neural Crest Development | Integumentary System Development)
- Merkel cell - An epidermal-derived cell in touch-sensitive area of the epidermis and mediate mechanotransduction in the skin. Previously thought to be neural crest in origin, but recently shown to arise from the embryonic epithelium. The cells are named after Friedrich Sigmund Merkel, a German anatomist who was the first to describe them in 1875. (More? Touch | Lecture - Integumentary Development | PMID 19786578 | PMID 3782861)
- merocrine gland - (sweat gland, eccrine sweat) simple tubular glands located at the border between the dermis and hypodermis. These glands regulate the body temperature. (More? image - merocrine secretion)
- nestin - (neuroectodermal stem cell marker) an intermediate filament protein (type VI) expressed in stem cells and transiently during development, and in cells within hair follicles, sebaceous and sweat glands.
- papillary layer - dermis sublayer that appears less dense and contains more cells lying close beneath the epidermis. (More? image)
- pilosebaceous unit - term used to describe a hair and its associated structures: hair follicle, arrector pili muscle and sebaceous gland.
- rete ridge - the extensions of the epidermis into the dermis. These epidermal surface thickenings extend downward between underlying connective tissue dermal papillae. This is also the site of initial eccrine gland differentiation.
- reticular layer - dermis sublayer that appears denser and contains fewer cells with thick collagen bundles lying beneath the papillary layer parallel to the skin surface. (More? image)
- root sheath - cell layers that surround the hair.
- sebaceous gland - holocrine gland associated with both the hair follicle and hairless parts of the skin (lips, cheek oral surface and external genitalia). Embedded in the dermis and are sites of infections (acne).
- simple - consisting of a single cell layer.
- terminal hairs - hair seen in obviously hairy parts of the body.
- thick skin - refers to the skin histology found on the palms of the hand and soles of the feet, does not contain hair. Note that this is used as a histological term not a measurement of overall skin thickness.
- thin skin - refers to the skin histology found on skin on all body regions, other than palms and soles (thick skin).
- vellus hairs - fine short hairs only lightly pigmented covering the body.
- vernix caseosa - (vernix, Latin, "caseosa" = cheese-like) a fetal protective coating consisting of sebum, skin cells and lanugo hair. Forming late in fetal development in a rostra-caudal sequence associated with epithelium differentiation.
- Voigt's lines - clinical term to describe the skin borders between areas of innervations by specific peripheral cutaneous nerves. (More? Sensory Touch | Historic Terminology)
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Cite this page: Hill, M.A. (2024, April 18) Embryology Integumentary System Development - Vernix Caseosa. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Integumentary_System_Development_-_Vernix_Caseosa
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