Advances in Fingerprint Technology.pdf

Table 3.7 Changes in Surface Lipid Composition with Age
Age
Free
Fatty
Acids Triglycerides
Wax
Esters Cholesterol
Cholesterol
Esters Squalene
5 days 1.5 51.9 26.7 2.5 6.1 9.9
1 month–2 years 20.8 38.4 17.6 3.7 10.3 9.4
2–4 years 22.9 49.6 8.0 4.2 8.9 6.2
4–8 years 15.9 45.6 6.9 7.2 14.6 7.7
8–10 years 17.8 47.4 17.8 3.2 5.7 8.3
10–15 years 18.8 42.9 23.6 1.8 4.2 8.4
18–45 years 16.4 41.0 25.0 1.4 2.1 12.0
Source: Ramasastry, P., Downing, D. T., Pochi, P. E., and Strauss, J. S., Chemical composition of human
skin surface lipids from birth to puberty, J. Invest. Dermatol., 54(2), 143, 1970. With permission.
Newborns
One study94 of neonatal skin surface lipids (from vernix caseosa, a grayishwhite
substance that covers the skin of the fetus and newborn) reported the
following lipid classes and amounts: sterol esters, 35%; triglycerides, 26%;
wax esters, 12%; squalene, 9%; free sterols, 9%; diesters, 7%; and miscellaneous
lipids, 4%. These values show more similarity to adult sebum profiles
than to young children. The composition of wax ester fatty acids (with regard
to the chain type and the amount of saturated and unsaturated) in vernix
caseosa has been found to be quite similar to that of adults. 82 However, the
amount of sterol esters showed considerable difference. In adults, sterol esters
constituted approximately 2.81% of the skin surface lipids, whereas vernix
caseosa contained 25.4%. The large percentage of high molecular weight
sterol esters in vernix caseosa probably helps to provide a waxy coating of
low water solubility that prevents excessive wetting of fetal skin. Fatty acids
in vernix caseosa were predominantly saturated (65%) while adult samples
were primarily mono-unsaturated (54%). A study of vernix caseosa by Miettienen
and Lukkäinen found at least eight additional sterols besides cholesterol,
including lanosterol. 95
The vernix caseosa of male fetuses contained much more sebum than
those of female fetuses, which had a higher proportion of epidermal lipids. 75
The differences were significant enough to be able to distinguish the sex of
the fetus based on the thin layer chromatogram of lipids extracted from the
vernix caseosa. Although androgen levels are high in newborns, the level of
hormones (as well as sebum production) drops rapidly during subsequent
months. 96 This leads to a dramatic change in the amount and composition
of excreted lipids.