Biliary phosphatidylcholine and lysophosphatidylcholine profiles in sclerosing cholangitis

Table 1 Clinical characteristics of the four included patient groups

	Controls (n = 11)	PSC (n = 14)	SSC (n = 10)	CCC (n = 6) with PSC (n = 2)	P value
Gender (M/F)	9/2	10/4	10/0	3/3
Age at ERC (yr)	52.8 ± 6.6	41.1 ± 2.3	52.1 ± 4.0	64.5 ± 5.2	0.02; PSCa
Serum albumin level (g/L)	41.5 ± 1.5	39.2 ± 1.9	37.6 ± 3.1	34.5 ± 1.4	0.13
	(ND in 3)		(ND in 5)
Serum AP level (U/L)	221.3 ± 99.9	271.5 ± 37.1	1004 ± 304	357 ± 62.4	0.003; controlsd
	(ND in 1)		(ND in 3)
Serum bilirubin level (mg/dL)	1.6 ± 0.5	2.7 ± 0.8	5.3 ± 2.3	4.9 ± 1.9	0.39
	(ND in 1)		(ND in 2)
Sterile bile or scarce bacterial growth/moderate or abundant bacterial growth	6/5	9/5	5/5	4/1 (ND in 1)
Intake of UDCA (yes/no)	0/11	13/1	6/2	3/3
			(2 unknown)
Dominant bile duct stenosis (yes/no)	0/11	4/10	1/9	6/0
Choledocholithiasis and/or sludge (yes/no)	9/2	0/14	2/8	0/6
Diagnosis of inflammatory bowel disease (yes/no)	0/11	10/4	0/10	2/4

M: Male; F: Female; PSC: Primary sclerosing cholangitis; AP: Alkaline phosphatase; ERC: Endoscopic retrograde cholangiography; UDCA: Ursodeoxycholic acid; ND: Not done.

^aP < 0.05 vs Cholangiocellular carcinoma (CCC);

^dP < 0.01 vs Secondary sclerosing cholangitis (SSC).

Table 2 Phospholipids used as internal standards to determine phospholipid concentrations in bile

	Fatty acid(s)	Molecular structure name	Provider
LPC standards
482 Da	15:00	1-pentadecanoyl-2-hydroxy-sn-glycero-3-PC	Avanti (Alabaster, AL, United States)
552 Da	20:00	1-arachidoyl-2-hydroxy-sn-glycero-3-PC	Avanti (Alabaster, AL, United States)
PC standards
622 Da	12:0/12:0	1, 2-didodecanoyl-sn-glycero-3-PC	Sigma (Deisenhofen, Germany)
678 Da	14:0/14:0	1, 2-tetradecanoyl-sn-glycero-3-PC	Sigma (Deisenhofen, Germany)
846 Da	20:0/20:0	1, 2-dieicosanoyl-sn-glycero-3-PC	Sigma (Deisenhofen, Germany)
902 Da	22:0/22:0	1, 2-didocosanoyl-sn-glycero-3-PC	Sigma (Deisenhofen, Germany)

PC: Phosphatidylcholine.

Table 3 Results of biochemical bile analyses of 41 human bile samples from four patient groups

	Controls (n = 11)	PSC (n = 14)	SSC (n = 10)	CCC (n = 6) with PSC (n = 2)	P value
Bile bilirubin (mg/dL)	41.6 ± 11.1	11.3 ± 1.8	6.0 ± 1.7	14.0 ± 6.4	0.006; controlsb
	1 ND	2 ND, 1 BLD	1 BLD
Bile protein (g/dL)	3.5 ± 0.9	3.1 ± 0.5	12.5 ± 9.5	3.7 ± 1.0	0.89
	1 ND	3 ND	1 BLD
Bile cholesterol (mmol/L)	1.10 ± 0.32	0.53 ± 0.18	0.25 ± 0.07	0.31 ± 0.13	0.10
	2 BLD	4 BLD	4 BLD
Bile total bile acids (mmol/L)	21.3 ± 3.1	17.4 ± 6.8	7.8 ± 3.1	5.9 ± 1.5	0.003; controlsb, controlsc
Bile total PC per volume (μmol/L)	8030 ± 1843	6205 ± 1465	2501 ± 790	1969 ± 981	0.005; controlsa, controlsc
Bile total LPC per volume (μmol/L)	256 ± 90	200 ± 97	91.3 ± 50.0	12.2 ± 5.4	Over-all 0.02; Dunn’s post-test: NS
LPC/PC (molar ratio)	0.04 ± 0.01	0.09 ± 0.05	0.03 ± 0.011	0.008 ± 0.001	0.54
PC/bilirubin (molar ratio)	0.13 ± 0.07	0.35 ± 0.08	0.30 ± 0.07	0.24 ± 0.09	0.09
PC/protein [μmol/L/(g/dL)]	5131 ± 1918	3597 ± 1350	2782 ± 2241	725 ± 229	0.09
PC/cholesterol (molar ratio)	8.9 ± 2.6	14.0 ± 3.8	8.4 ± 1.4	6.2 ± 2.3	0.46
PC/bile acids (molar ratio)	0.40 ± 0.07	0.45 ± 0.06	0.34 ± 0.07	0.31 ± 0.09	0.45

¹One value was excluded (outlier); for calculation of SEM, values below detection level were set at 0; ND: Not done (not sufficient material left for determination); BLD: Below limit of detection; NS: Not significant; PSC: Primary sclerosing cholangitis; SSC: Secondary sclerosing cholangitis; CCC: Cholangiocellular carcinoma.

^aP < 0.05,

^bP < 0.01 vs SSC;

^cP < 0.05 vs CCC.

Table 4 Molar percentages of phosphatidylcholine and lysophosphatidylcholine species in bile from four patient groups

	Molecular weight (Da)	Controls (n = 11)	PSC (n = 14)	SSC (n = 10)	CCC ± PSC (n = 6)	P value
PC molecular species
32:1	732	2.8 ± 0.5	3.3 ± 0.4	9.2 ± 3.9	4.2 ± 0.7	0.036, controls vs SSCa
32:0	734	1.1 ± 0.1	1.4 ± 0.2	3.6 ± 1.2	1.5 ± 0.2	0.029, controls vs SSCa
34:3	756	2.2 ± 0.3	2.7 ± 0.2	2.7 ± 0.4	2.0 ± 0.4	0.19
34:2	758	33.7 ± 1.1	28.5 ± 0.7	25.8 ± 3.1	29.8 ± 0.2	0.017, controls vs PSCc
34:1	760	22.8 ± 0.9	22.1 ± 0.7	22.2 ± 0.9	24.1 ± 1.3	0.55
36:4	782	10.5 ± 0.6	10.3 ± 0.7	10.1 ± 1.8	8.6 ± 0.5	0.24
36:3	784	8.8 ± 0.3	10.0 ± 0.4	8.4 ± 0.8	7.1 ± 0.7	0.013, CCC vs PSCc
36:2	786	7.3 ± 0.4	9.0 ± 0.6	8.1 ± 0.9	9.3 ± 0.9	0.13
36:1	788	3.3 ± 0.3	3.5 ± 0.3	3.7 ± 0.4	3.2 ± 0.4	0.65
38:7	804	0.8 ± 0.2	0.9 ± 0.3	0.4 ± 0.3	0.2 ± 0.1	0.10
38:6	806	2.6 ± 0.2	3.3 ± 0.3	2.5 ± 0.5	6.3 ± 2.5	0.05
38:5	808	2.1 ± 0.1	2.7 ± 0.3	1.6 ± 0.4	2.0 ± 0.3	0.09
38:4	810	1.9 ± 0.2	2.3 ± 0.3	1.8 ± 0.4	1.9 ± 0.3	0.51
LPC molecular species
16:0	496	59.2 ± 7.0	56.0 ± 5.8	85.0 ± 5.2	58.9 ± 7.0	0.05, controls vs SSCa, PSC vs SSCb
18:2	520	21.2 ± 6.0	12.6 ± 4.0	0.9 ± 0.9	30.0 ± 9.0	0.02, stones vs SSCa, CCC vs SSCb
18:1	522	9.7 ± 2.3	16.0 ± 2.9	7.4 ± 2.6	4.0 ± 4.0	0.08
18:0	524	9.9 ± 5.4	15.5 ± 2.3	6.8 ± 2.2	7.2 ± 7.2	0.06

^aP < 0.05,

^bP < 0.01 vs secondary sclerosing cholangitis (SSC) group;

^cP < 0.05 vs primary sclerosing cholangitis (PSC). CCC: Cholangiocellular carcinoma; PC: Phosphatidylcholine; LPC: Lysophosphatidylcholine.