Table 4. Concentration of individual species of phosphatidyl-ethanolamine (PE) and plasmenyl- ethanolamine (PlsE) in erythrocytes from controls and diabetic patients without or with mild, moderate, severe or proliferative diabetic retinopathy (results are expressed as µg of mg phospholipids for PE species and as ratio to internal standard PC14∶0/14∶0 for PlsE species).
| Patients with diabetic retinopathy | |||||||||||||
| Controls | Diabetic patients | mild | moderate | severe | proliferative | ||||||||
| n = 18 | n = 14 | n = 12 | n = 12 | n = 22 | n = 24 | ||||||||
| [M+H]+ or MS/MS transition | median | [IQR] | median | [IQR] | median | [IQR] | median | [IQR] | median | [IQR] | median | [IQR] | |
| PE14∶1/16∶2 b | 658.40 | <0.01 | - | <0.01 | - | <0.01 | - | 0.01 | [0.00–0.02] | <0.01 | - | <0.01 | - |
| PE16∶0/16∶1 | 690.53 | 0.53 | [0.45–0.80] | 0.43 | [0.23–0.74] | 0.58 | [0.42–0.63] | 0.36 | [0.30–0.43] | 0.46 | [0.31–0.56] | 0.34 | [0.25–0.49] |
| PE16∶0/16∶0 | 692.54 | 1.12 | [0.76–1.29] | 0.89 | [0.40–1.50] | 0.93 | [0.76–1.06] | 0.64 | [0.39–0.83] | 0.93 | [0.60–1.28] | 0.63 | [0.44–0.93] |
| PE16∶1/18∶2 | 714.50 | 0.69 | [0.50–0.81] | 0.68 | [0.48–1.09] | 1.15 | [0.77–1.21] | 0.59 | [0.50–0.68] | 0.71 | [0.61–0.77] | 0.54 | [0.30–0.69] |
| PE16∶0/18∶2+ PE16∶1/18∶1 | 716.54 | 10.86 | [9.35–14.48] | 11.97 | [5.88–16.70] | 14.22 | [13.42–15.89] | 8.34 a | [7.62–8.76] | 11.96 | [7.56–13.30] | 8.53 | [5.95–11.28] |
| PE16∶0/18∶1 | 718.56 | 37.91 | [30.40–47.15] | 41.33 | [34.13–47.58] | 54.62 a | [41.54–56.27] | 32.60 | [28.65–35.12] | 41.68 | [33.18–50.10] | 31.26 | [23.09–39.71] |
| PE16∶0/18∶0 | 720.57 | <0.01 | - | <0.01 | - | <0.01 | - | 0.02 | [0.00–0.18] | <0.01 | - | <0.01 | - |
| PE16∶1/20∶4+ PE16∶0/20∶5 | 738.50 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | 0.20 | [0.00–0.68] |
| PE16∶0/20∶4+ PE18∶2/18∶2 | 740.54 | 14.75 | [9.45–16.65] | 13.65 | [7.91–17.77] | 13.73 | [12.96–18.52] | 9.18 | [0.74–16.47] | 15.32 | [10.10–18.39] | 14.23 | [6.62–16.35] |
| PE16∶0/20∶3+ PE18∶1/18∶2 | 742.56 | 10.17 | [7.92–13.96] | 9.92 | [6.17–12.14] | 12.02 | [10.97–14.93] | 8.04 | [5.50–11.05] | 11.19 | [7.18–11.49] | 8.84 | [4.67–9.13] |
| PE18∶1/18∶1+ PE18∶0/18∶2 | 744.57 | 14.19 | [11.39–18.07] | 15.09 | [12.19–18.87] | 18.55 | [16.70–19.93] | 13.94 | [10.30–14.96] | 14.72 | [13.39–15.35] | 12.20 | [8.65–15.54] |
| PE18∶0/18∶1 | 746.59 | 10.78 | [8.17–11.75] | 10.42 | [8.94–12.26] | 12.28 | [8.90–14.75] | 8.53 | [7.03–8.80] | 12.65 | [10.56–13.04] | 8.54 | [6.86–10.72] |
| PE18∶0/18∶0 | 748.55 | <0.01 | - | <0.01 | - | <0.01 | - | 0.13 | [0.00–0.30] | <0.01 | - | <0.01 | - |
| PE18∶2/20∶4+ PE16∶0/22∶6 | 765.54 | 11.61 | [9.02–14.88] | 8.23 a | [5.00–12.09] | 7.67 a | [5.95–11.06] | 4.28 | [4.01–14.09] | 10.33 | [5.67–11.45] | 8.31 a | [1.63–11.25] |
| PE18∶1/20∶4+ PE16∶0/22∶5+ PE18∶0/20∶5 | 766.56 | 16.08 | [14.05–18.74] | 11.87 a | [5.71–14.33] | 10.87 | [9.40–17.69] | 13.42 | [9.22–16.08] | 13.24 | [7.77–13.74] | 12.54 | [3.27–15.08] |
| PE18∶0/20∶4 | 768.57 | 20.97 | [18.64–25.50] | 16.22 a | [10.34–21.32] | 14.99 | [12.724–22.21] | 13.87 | [11.34–21.73] | 18.42 | [10.64–21.98] | 18.78 | [6.52–20.95] |
| PE18∶0/20∶3 | 770.59 | 0.56 | [0.15–1.58] | 1.04 | [0.64–1.30] | 1.10 | [0.36–1.51] | 0.77 | [0.17–1.21] | 1.26 | [0.74–1.43] | 0.59 | [0.39–0.98] |
| PE18∶0/20∶2 | 772.60 | 0.48 | [0.30–0.69] | 0.73 | [0.61–1.07] | 0.72 | [0.21–1.10] | 0.31 | [0.19–0.82] | 0.69 | [0.57–0.90] | 0.49 | [0.36–0.64] |
| PE18∶0/20∶1 | 774.56 | 0.23 | [0.15–0.40] | 0.37 | [0.08–0.41] | 0.23 | [0.06–0.37] | 0.30 | [0.24–0.69] | 0.20 | [0.01–0.50] | 0.20 | [0.15–0.29] |
| PE18∶0/20∶0 | 776.50 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | 0.04 | [0.00–0.11] |
| PE20∶4/20∶4 | 788.54 | 1.72 | [1.37–2.02] | 1.34 | [0.57–2.03] | 1.43 | [1.11–1.93] | 1.15 | [0.96–1.25] | 1.56 | [0.74–2.01] | 0.91 | [0.52–1.39] |
| PE18∶1/22∶6 | 790.56 | 6.86 | [5.99–7.57] | 4.57 | [3.14–6.34] | 4.93 | [3.08–6.11] | 3.14 a | [1.21–4.63] | 5.46 | [1.79–7.21] | 3.25 a | [1.41–4.92] |
| PE18∶0/22∶6 | 792.57 | 6.64 | [6.31–7.41] | 4.71 | [2.62–7.11] | 3.51 a | [2.98–5.55] | 4.44 a | [3.25–5.24] | 5.18 a | [1.76–5.70] | 3.60 a | [1.12–5.29] |
| PE18∶0/22∶5+ PE18∶1/22∶4 | 794.59 | 5.89 | [5.08–6.26] | 3.69 | [2.39–6.75] | 3.49 | [3.02–6.30] | 4.09 | [1.60–5.01] | 5.10 | [1.91–5.57] | 3.82 | [1.75–5.33] |
| PE18∶0/22∶4+ PE20∶0/20∶4 | 796.60 | 2.94 | [2.70–3.24] | 2.53 | [1.30–3.07] | 2.61 | [1.77–3.52] | 3.01 | [1.93–3.39] | 3.76 | [1.21–4.01] | 1.64 | [1.07–3.91] |
| PE20∶0/20∶3+ PE18∶2/22∶1 | 798.62 | 0.04 | [0.00–0.12] | 0.03 | [0.00–0.37] | 0.39 a | [0.16–0.45] | <0.01 | - | 0.05 | [0.00–0.39] | 0.12 a | [0.00–0.23] |
| PE20∶0/20∶2 | 800.65 | <0.01 | - | <0.01 | - | <0.01 | - | 0.05 | [0.00–0.12] | <0.01 | - | <0.01 | - |
| PE20∶4/22∶6 | 812.52 | 0.75 | [0.51–0.91] | 0.45 | [0.21–0.84] | 0.31 a | [0.23–0.46] | 0.40 a | [0.23–0.46] | 0.32 a | [0.18–0.48] | 0.40 a | [0.17–0.52] |
| PE20∶4/22∶5+ PE20∶3/22∶6 | 814.56 | 0.47 | [0.33–0.59] | 0.34 | [0.17–0.54] | 0.26 a | [0.12–0.29] | 0.12 a | [0.01–0.36] | 0.21 a | [0.13–0.59] | 0.13 a | [0.07–0.34] |
| PE20∶2/22∶6+ PE20∶4/22∶4 | 816.50 | <0.01 | - | <0.01 | - | <0.01 | - | 0.11 | [0.00–0.24] | <0.01 | - | 0.01 | [0.00–0.11] |
| PE20∶1/22∶6 | 818.56 | 0.63 | [0.33–0.81] | 0.27 | [0.06–0.72] | 0.30 | [0.25–0.47] | 0.35 | [0.24–0.55] | 0.28 | [0.18–0.40] | 0.20 | [0.08–0.38] |
| PE20∶0/22∶6+ PE20∶2/22∶4 | 820.55 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | 0.01 a | [0.00–0.14] |
| PE20∶0/22∶4 | 824.63 | 0.15 | [0.09–0.29] | 0.10 | [0.06–0.26] | 0.16 | [0.02–0.25] | 0.15 | [0.06–0.24] | 0.10 | [0.00–0.25] | 0.06 | [0.03–0.16] |
| PE22∶6/22∶6 | 836.56 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - |
| PE22∶5/22∶6 | 838.60 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - |
| PE22∶4/22∶6 | 840.50 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - |
| PE22∶3/22∶6 | 842.60 | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - | <0.01 | - |
| PlsE16∶0/20∶4 | 722 ->303 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0013 a | [0.0013–0.0013] | 0.0001 | [0.0000–0.0011] | 0.0003 a | [0.0000–0.0038] |
| PlsE16∶0/20∶3 | 724 ->305 | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - |
| PlsE18∶0/18∶1 | 728 ->281 | 0.0074 | [0.0073–0.0074] | 0.0026 | [0.0013–0.0279] | 0.0022 | [0.0018–0.0048] | 0.0199 | [0.0198–0.0304] | 0.0050 | [0.0017–0.0094] | 0.0115 | [0.0068–0.0177] |
| PlsE16∶0/22∶6 | 746 ->327 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0005 | [0.0000–0.0010] | <0.0001 | - | <0.0001 | - |
| PlsE18∶1/20∶4 | 748 ->303 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0005 a | [0.0000–0.0015] | <0.0001 | - | 0.0001 | [0.0000–0.0017] |
| PlsE16∶0/22∶5 | 748 ->329 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0011 a | [0.0010–0.0011] | 0.0001 | [0.0000–0.0010] | 0.0001 a | [0.0000–0.0029] |
| PlsE18∶0/20∶4 | 750 ->303 | 0.0160 | [0.0159–0.0160] | 0.0070 | [0.0043–0.0113] | 0.0050 | [0.0036–0.0149] | 0.0065 | [0.0064–0.0154] | 0.0086 | [0.0057–0.0097] | 0.0095 | [0.0010–0.0202] |
| PlsE16∶0/22∶4 | 750 ->331 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0016 | [0.0012–0.0015] | 0.0001 | [0.0000–0.0014] | 0.0004 | [0.0004–0.0035] |
| PlsE18∶1/22∶6 | 772 ->327 | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - | <0.0001 | - |
| PlsE18∶0/22∶6 | 774 ->327 | 0.0003 | [0.0002–0.0002] | <0.0001 | - | <0.0001 | - | 0.0005 | [0.0000–0.0010] | <0.0001 | - | 0.0002 | [0.0000–0.0005] |
| PlsE18∶1/22∶4 | 776 ->331 | 0.0001 | [0.0001–0.0001] | <0.0001 | - | <0.0001 | - | 0.0001 | [0.0000–0.0007] | 0.0001 | [0.0000–0.0001] | 0.0001 | [0.0000–0.0008] |
| PlsE18∶0/22∶5 | 776 ->329 | 0.0026 | [0.0025–0.0025] | 0.0012 | [0.0005–0.0030] | 0.0008 | [0.0002–0.0027] | 0.0008 | [0.0008–0.0033] | 0.0015 | [0.0005–0.0016] | 0.0020 | [0.0002–0.0043] |
| PlsE18∶0/22∶4 | 778 ->329 | 0.0204 | [0.0203–0.0203] | 0.0040 a | [0.0013–0.0074] | 0.0037 a | [0.0033–0.0060] | 0.0076 a | [0.0005–0.01528] | 0.0071 a | [0.0022–0.0099] | 0.0039 a | [0.0002–0.0068] |
| total PlsE | - | 0.0473 | [0.0472–0.0472] | 0.0233 a | [0.0111–0.0321] | 0.0126 a | [0.0094–0.0374] | 0.0317 | [0.0317–0.0663] | 0.0235 a | [0.0167–0.0293] | 0.0394 | [0.0178–0.0654] |
| total PlsE with 22∶6 | - | 0.0004 | [0.0003–0.0003] | <0.0001 a | - | <0.0001 a | - | 0.0010 | [0.0000–0.0020] | 0.0001 a | [0.0000–0.0002] | 0.0002 | [0.0000–0.0006] |
| total PE with 22∶6 | - | 27.35 | [23.49–32.80] | 17.53 a | [11.41–26.08] | 15.57 a | [13.17–25.91] | 13.30 a | [11.35–25.90] | 23.34 a | [10.04–28.40] | 17.45 a | [4.62–23.60] |
| total PE | - | 186.75 | [149.97–206.15] | 163.49 | [110.80–206.00] | 169.34 | [158.12–217.51] | 125.12 a | [113.43–159.51] | 180.88 | [125.98–203.57] | 147.46 a | [84.46–170.59] |
[M+H]+ for PE species and MS/MS transition for PlsE species.
Abbreviations of individual PE and PlsE species are as follows: position on the glycerol backbone as shown as sn-1/sn-2 of the fatty acid and fatty alcohol radicals (abbreviated as number of carbons: number of double bonds).
a
Based on Kruskall-Wallis test, significantly different when compared to controls (P<0.05).