Oxidative stress biomarkers in pediatric sepsis: a prospective observational pilot study

Figures & data

Figure 1. Oxidative stress biomarkers in relation to age in control subjects. (a) Correlation between age and SOD activity; (b) Correlation between age and FRAP. SOD, superoxide dismutase; FRAP, ferric reducing ability of plasma.

Table 1. Demographic characteristics and oxidative stress biomarkers in control subjects.

Variable
Gender, n (%)
Female	21 (43)
Male	28 (57)
Age (months)^b	30.0 (16.5–50.0)
FRAP (μmol Fe^+2/L)^b	148.4 (123.5–176.1)
GSH (μmol/g Hb)^a	4.49 ± 0.79
GSSG (μmol/g Hb)^a	0.17 ± 0.04
SOD (U/g Hb)^a	213.9 ± 35.8
Catalase (k/g Hb)^a	466.3 ± 145.7
GSH-Px (U/g Hb)^b	3.52 (2.98–4.65)
F2-isoprostanes (pg/mL)^a	8.42 ± 4.30

Values in ^amean ± standard deviation, ^bmedian (interquartile range).

FRAP, ferric reducing ability of plasma; GSH, reduced glutathione; GSSG, oxidized glutathione; SOD, superoxide dismutase; GSHPx, glutathione peroxidase.

Table 2. Demographic and clinical characteristics of control group and patients with sepsis.

	Control	Non-severe sepsis	Severe sepsis
Number of subjects	42	21	21
Age (months)^a	25.5 (13.8–47.5)	22.0 (11.5–52.5)^ns	20 (5.5–30.0)^ns
Gender, n (%)
Female	18 (43)	7 (33)	11 (52)
Male	24 (57)	14 (67)	10 (48)
Criteria for sepsis diagnosis at admission
Core temperature (degrees celsius)^b		39.0 (38.3–40)	39.0 (37.2–40.2)
Heart rate (beats/min)^b		162 (135–230)	180 (143–208)
Respiratory rate (breaths/min)^b		39 (29–60)	36 (23–70)
Leukocyte count (leukocytes ×10^3/mm^3)^b		11.6 (2.8–2.1)	9.7 (2.4–37.8)
PELOD score^a		1 (0–1)	13 (11–21)*
Mortality, n (%)		0	2 (9.5)
PICU length of stay (days)^a		2.0 (1.5–3.5)	5.5 (3.0–9.5)*
Total hospital length of stay (days)^a		10.0 (8.0–13.0)	15.0 (10.0–28.0)*
Duration of mechanical ventilation (hours)^a		0.0	90.0 (37.5–163.5)*
Use of stress-dose corticosteroids, n (%)		0	11 (52)
Infection site, n (%)
Respiratory		6 (28.6)	6 (28.6)
Skin		2 (9.5)	6 (28.6)
Bacteremia		2 (9.5)	5 (23.8)
Abdominal		5 (23.8)	1 (4.8)
Central nervous system		3 (14.3)	2 (9.5)
Urinary		3 (14.3)	1 (4.8)
Microbiological confirmation, n (%)
Gram-positive bacteria		4 (19.0)	8 (38.1)
Gram-negative bacteria		5 (23.8)	4 (19.0)
Polybacterial		1 (4.8)	1 (4.8)
Fungal		0	0
Viral		0	0
Positive blood culture, n (%)		4 (19.0)	8 (38.1)

^aValues in median (interquartile range).

^bValues in median (range).

^nsNonsignificant compared to control.

*P < 0.05 when compared with non-severe sepsis.

Table 3. Oxidative stress biomarkers in control group and patients with sepsis.

	Control	Admission		Day 2
		Non-severe sepsis	Severe sepsis	Non-severe sepsis	Severe sepsis
FRAP (μmol Fe^+2/L)	155.7 (129.7–177.1)	216.5 ± 73.2**	203.8 ± 92.0*	198.1 ± 67.2	228.0 ± 108.6**
Thiol index	27.60 ± 5.83	9.67 ± 6.88***	8.31 ± 6.71***	9.76 ± 6.85***	6.08 ± 5.29***
SOD (U/g Hb)	213.8 ± 36.1	161.9 ± 32.3***	144.0 ± 48.7***	165.9 ± 42.9***	145.8 (128.2–161.7)***
Catalase (k/g Hb)	464.9 ± 147.5	359.7 ± 118.3	284.2 ± 82.9***^, ^§	387.9 ± 119.1	284.7 ± 20.8***^, ^§
GSHPx (U/g Hb)	3.50 (2.97–4.64)	4.98 ± 1.54**	4.17 ± 0.75	5.00 ± 1.24**	4.28 ± 1.09
F2-isoprostanes (pg/mL)	8.17 ± 4.52	14.97 ± 8.45**	19.69 ± 12.99***	18.43 ± 13.89**	26.99 ± 16.52***

*P < 0.05.

**P < 0.01.

***P < 0.001, compared to control.

^§ P < 0.05, compared to non-severe sepsis.

FRAP, ferric reducing ability of plasma; SOD, superoxide dismutase; GSHPx, glutathione peroxidase.

Figure 2. Biomarkers of oxidative stress in patients with sepsis according to clinical severity as estimated by the probability of dying and vasoactive drug requirement. (a) FRAP, day 2; (b) Catalase, day 1; (c) F₂-isoprostanes, day 2; (d) FRAP, day 2. *P < 0.05; **P < 0.01. FRAP, ferric reducing ability of plasma.

Figure 3. Nuclear factor-kappa B activation at day 2. (a) p50 subunit; (b) p65 subunit. *P < 0.05. OD, optical density.