Bench-to-bedside review: Sepsis - from the redox point of view

Table 2 Redox characteristics of plasma in adults with sepsis

	Patient groups		Method	Reference
Anti-oxidant
Ascorbate (mg/L)	Control: 1.71 ± 0.46	Sepsis: 0.55 ± 0.28	Spectrophotometric assay	[116]
	Control: 4.5 to 12	Critically injured: 1.1 ± 0.3	HPLC	[117]
Retinol (μg/L)	Control: 735 ± 183	Septic shock: 265 ± 193	HPLC	[118]
Tocopherol (mg/L)	Control: 11.5 ± 1.3	Septic shock: 3.6 ± 2.0	HPLC	[118]
β-Carotene (μg/L)	Control: 619 ± 259	Septic shock: <101	HPLC	[118]
Lycopene (μg/L)	Control: 522 ± 184	Septic shock: <154	HPLC	[118]
Oxidative stress biomarkers
Total plasma thiols (R-SH) (μmol/L)	Control: 364 ± 22	Sepsis: 138 ± 14	Ellman's method	[119]
Lipid peroxidation (μmol/L)	Control: <2	Patients with >3 failing organs: 4.9 ± 2.3	TBARS assay	[118]
	Control: 0.92 ± 0.39	Sepsis survivors: 0.99 ± 0.14	TBARS assay	[120]
		Sepsis non-survivors: 3.33 ± 2.29
Lipid peroxidation (nmol/mg of protein)	Sepsis (day 1): 2.4	Sepsis (day 7): 2.9	FOX assay	[121]
Total anti-oxidant capacity (nmol/mg of protein)^a	Sepsis (day 1): 1.5	Sepsis (day 7): 1.1	ABTS assay	[121]
Total anti-oxidant capacity (%)	Control: 57.3 to 60.3	Survivors: 51.4 to 55.4	ABTS assay	[30]
		Non-survivors: 46.1 to 47.6
Total anti-oxidant capacity (μmol/L)	Control: 354 ± 9	Sepsis: 265 ± 32	TRAP assay	[31]
		Septic shock: 452 ± 34

^aThe use of total anti-oxidant capacity assays is associated with some pitfalls; therefore, the results obtained with such methods should be taken with some caution. For example, urate interferes with both the ABTS and the TRAP assays, potentially leading to falsely high values [23]. Urate increases in many pathophysiological conditions, for example, in renal failure, which may develop in sepsis. Another problem is that plasma contains a complex mixture of anti-oxidants that react at different rates, so some of them may not be detected by rapid assays [23]. ABTS, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid); FOX, ferrous oxidation-xylenol orange; HPLC, high-performance liquid chromatography; TBARS, thiobarbituric acid reactive substances; TRAP, total radical-trapping antioxidant potential.

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