TABLE 1.

Molecular percentage of lipid classes determined by ESI-MS

	Young Donors		Old Donors
Lipid Class	Early Passage	Late Passage	Early Passage	Late Passage
PC diacyl	37.3 ± 2.7	37.4 ± 3.4	35.5 ± 2.4	39.0 ± 3.7
PC alkyl	5.8 ± 0.3	5.1 ± 0.4**	5.3 ± 0.5	6.6 ± 0.8*
PE diacyl	20.4 ± 1.1	15.1 ± 2.1*	19.9 ± 3.8	17.2 ± 3.4
PE alkenyl	16.1 ± 2.1	22.7 ± 4.7*	16.8 ± 2.6	16.5 ± 1.9
PI	3.9 ± 1.2	7.7 ± 1.7*	5.4 ± 1.3	8.2 ± 3.4
PS	8.0 ± 4.8	4.9 ± 1.1	5.3 ± 1.1	5.9 ± 2.1
PI/PS	0.5 ± 0.2	1.6 ± 0.4*	1.0 ± 0.1	1.4 ± 0.5
lysoPC	0.5 ± 0.1	1.5 ± 0.9	1.2 ± 0.5	1.2 ± 0.6

The totals for lipid classes were calculated by summing individual lipid species of each class. The statistical difference between the young and the old donors was calculated using Student two-tailed t-test (paired). *P < 0.05, **P < 0.01.