Association between high-mobility group box 1 levels and preeclampsia: a systematic review and meta-analysis

Previous studies had demonstrated that high-mobility group box 1 (HMGB1) levels were elevated in preeclampsia (PE). However, the conclusion remains controversial. This study aimed to investigate the association between blood and placenta HMGB1 levels and PE in pregnant women.

After a systematic literature search, eligible literature was screened according to inclusion and exclusion criteria. Data extraction and quality assessment were performed independently by two reviewers. The extracted data were analyzed using Review Manager 5.4 and STATA 12.0 software. Subgroup analysis and meta-regression analysis were conducted to find potential sources of heterogeneity.

Twelve studies were included, with a total of 1145 participants. Compared with normal pregnancies, pregnant women with PE had significantly higher blood HMGB1 levels (SMD = 1.34, 95% CI: 0.72-1.95, p < 0.0001). Similarly, the expression of placental HMGB1 in PE was higher than that in normal controls by using Western blot (MD = 0.37, 95% CI: 0.27-0.47, p < 0.00001) or immunohistochemistry (OR = 6.36, 95% CI: 1.48-27.25, p = 0.01). In addition, the blood HMGB1 levels were positively correlated with the severity of PE, with higher blood HMGB1 levels in severe PE than those in mild PE (SMD = 3.35, 95% CI: 0.63-6.06, p = 0.02). The subgroup analysis indicated a close association of blood HMGB1 with PE in the Asian group, but not in the European group.

Both blood and placental HMGB1 levels in patients with PE were significantly elevated, and higher blood HMGB1 levels indicated a more serious disease condition, suggesting that higher levels of HMGB1 were associated with the risk of PE.