Mitochondrial manganese superoxide dismutase mRNA expression in human chorioamniotic membranes and its association with labor, inflammation, and infection

Figures & data

Table I.  Demographic and clinical characteristics of the study population.

	Term not in labor (n = 29)	Term in labor (n = 29)	p-value	PPROM (n = 17)	PPROM with chorioamnionitis (n = 21)	p-value	PTL (n = 16)	PTL with chorioamnionitis (n = 12)	p-value
Maternal age (years)*	29 [22–33]	22 [19–25]	0.001	27 [22–31]	27 [22–34]	NS	24 [18–28]	21 [18–30]	NS
Gestational age at diagnosis (weeks)*	–	–		31 [30–32.9]	30 [25.6–31.4]	NS	26 [23.1–31.8]	28.9 [25.5–32]	NS
Gestational age at delivery (week)*	39.1 [38.7–39.4]	40 [39.6–40.4]	<0.001	31.7 [30.1–33.1]	31 [29.1–32.3]	NS	29.6 [24.2–33.1]	29.1 [25.6–32]	NS
Diagnosis to delivery interval (days)*	–	–		1 [0–5]	3 [1–10]	NS	3 [0.3–5]	1 [0–6.5]	NS
Gravidity*	3 [2.5–4.5]	2 [1–4]	NS	3 [1.5–6]	4 [2.5–5.5]	NS	3 [1–4]	3 [1.3–3]	NS
Parity*	2 [1–2]	1 [0–2]	<0.05	2 [0–3.5]	2 [1–4]	NS	1 [1–2]	0.5 [0–1]	NS
Birth-weight (g)*	3370 [3160–3765]	3220 [3100–3580]	NS	1530 [1365–1850]	1700 [995–1920]	NS	1040 [705–1870]	1045 [670–1683]	NS
Female fetus (%)^†	41.4 (12/29)	65.5 (19/29)	NS	29.4 (5/17)	33.3 (7/21)	NS	25 (4/16)	58.3 (7/12)	NS
Positive amniotic fluid culture (%)^†,‡	–	–		0 (0/8)	46.2 (6/14)	0.051	0 (0/11)	30 (3/10)	NS
Ethnic origin (%)^§			NS			NS			NS
African-American	65.5 (19/29)	93.1 (27/29)		82.4 (14/17)	90.5 (19/21)		87.5 (14/16)	83.3 (10/12)
Caucasian	13.8 (4/29)	3.4 (1/29)		17.6 (3/17)	9.5 (2/21)		12.5 (2/16)	16.7 (2/12)
Other	20.7 (6/29)	3.4 (1/29)		0 (0/17)	0 (0/21)		0 (0/16)	0 (0/12)

Values are presented as median [interquartile range] or percentage.

NS, Statistically not significant.

Comparisons between two groups were performed with the *Mann–Whitney test, ^†Fisher's exact test and ^§Pearson's chi-square test.

^‡PPROM (n = 8); PPROM with chorioamnionitis (n = 14); PTL (n = 11); PTL with chorioamnionitis (n = 10).

Table II.  Microorganisms detected in positive amniotic fluid cultures.

	PPROM with chorioamnionitis (n = 14)	PTL with chorioamnionitis (n = 10)
Ureoplasma ureolyticum	3	1
Mycoplasma hominis	1	2
Gardnerella vaginalis	2	–
Lactobacillus species	–	1
Peptostreptococcus species	1	–
Prevotella species	1	–
Candida albicans	1	–

Figure 1.  Mn SOD mRNA expression was 2.4-fold higher in the fetal membranes of women with spontaneous labor than in women who were not in labor at term (p = 0.02). Groups are represented by different colors. Y-axis represents units of −ΔC_t with an arbitrary zero point, so that each unit measures a two-fold change.

Figure 2.  The amount of Mn SOD mRNA was higher in the fetal membranes of patients presenting with spontaneous preterm labor without histological chorioamnionitis than (A) in women with spontaneous labor at term (7.2-fold, p = 0.03) or (B) in patients presenting with preterm PROM without histological chorioamnionitis (3.2-fold, p = 0.03).

Figure 3.  Mn SOD mRNA expression in the fetal membranes was increased when histological chorioamnionitis was present both in patients with (A) preterm PROM (3.8-fold, p = 0.02) or (B) spontaneous preterm labor (5.4-fold, p = 0.02).

Figure 4.  Mn SOD mRNA expression in the fetal membranes was higher in patients with spontaneous preterm labor and chorioamnionitis than in those with preterm PROM and chorioamnionitis (4.3-fold, p = 0.03).

Figure 5.  Among patients with preterm PROM, those who delivered a female neonate had a higher increase (13.4-fold, p = 0.047) in Mn SOD mRNA expression upon chorioamnionitis than those who delivered a male neonate (2.3-fold, p = 0.2).

Figure 6.  Among patients with spontaneous preterm labor, those who delivered a female neonate had a higher increase (12-fold, p = 0.047) in Mn SOD mRNA expression upon chorioamnionitis than those who delivered a male neonate (3.5-fold, p = 0.2).