Possible connection between elevated serum α-fetoprotein and placental necrosis during pregnancy: A case report and review of literature

Beyond liver cancer, more application scenarios for alpha-fetoprotein in clinical practice

Alpha-fetoprotein (AFP) is a commonly used clinical biomarker. Before 1970, the two-way agar diffusion method was mainly used, and the specificity of AFP in the diagnosis of primary liver cancer was satisfactory. However, its positivity rate was not very high. The diagnostic value of AFP is changing with the evolution of detection methods. Here, we performed a literature search to identify English-language publications. The search was performed from January 2015 to April 2023 using the PubMed database and the following terms in [Titles/Abstracts]: alpha-fetoprotein, clinical practice, detection, etc. The references of retrieved articles were also screened to broaden the search. Studies referring to liver cancer and AFP detection methods were excluded. In this review, several clinical application scenarios for AFP were systematically reviewed, and its potential detection value in the future was discussed.

Pregnancy outcomes of women with elevated second-trimester maternal serum alpha-fetoprotein

OBJECTIVE

The aim of this study was to investigate the overall distribution of pregnancy outcomes in women with elevated second-trimester maternal serum alpha-fetoprotein (MS-AFP), and to determine the risk of adverse pregnancy outcomes (APOs) by MS-AFP level.

MATERIALS AND METHODS

We retrospectively analyzed the clinical data of 429 women with elevated MS-AFP (≥2.5 multiple of the median (MOM)) and 1555 women with normal MS-AFP (0.5-2.49MOM) from a total of 46,741 prenatally screened singleton pregnant women. The overall distribution of APOs of the two groups, the risk of APOs by MS-AFP level, and the predictive value of elevated MS-AFP to APOs were analyzed.

RESULTS

The incidence rate of APOs in elevated MS-AFP group was significantly higher than that in normal MS-AFP group (42.89 vs. 8.23%). In elevated MS-AFP group, the top three APOs, in term of incidence rate, were structural fetal abnormalities (7.93%), spontaneous abortion (7.46%) and preterm birth (7.23%); regarding to the risk, the top three APOs were stillbirth, spontaneous abortion and early-onset preeclampsia (odds ratio 35.98, 20.81 and 8.58 respectively). For structural fetal abnormalities, MS-AFP had predictive values for fetal open neural tube defects (ONTDs), gastroschisis and multiple malformations.

CONCLUSION

Elevated MS-AFP is associated with increased risks of APOs. ONTDs complicate merely a small proportion of pregnancies with elevated MS-AFP, and the rest of them have high risks of obstetric complications. MS-AFP can help to identify these women at high risk of APOs in earlier second-trimester.

A rat model of placental inflammation explains the unexplained elevated maternal serum alpha-fetoprotein associated with adverse pregnancy outcomes

AIM

It has been reported in numerous studies that elevated maternal serum alpha-fetoprotein (MS-AFP) is associated with adverse pregnancy outcomes (APO), such as pre-eclampsia, stillbirth, preterm birth and fetal growth restriction. However, the mechanism linking elevated MS-AFP and APO is obscure. In this study, we tried to explore the mechanism by using pregnant rats.

METHODS

Lipopolysaccharide (LPS) was used to induce placental inflammation in pregnant rats. Maternal serum and placental inflammatory cytokines and placental morphology were used to assess the level of placental inflammation. The incidences of APO and the levels of MS-AFP were evaluated. The expressions of alpha-fetoprotein (AFP) in the related organs and fetal serum AFP levels were detected.

RESULTS

Compared to saline-treated pregnant rats, LPS led to elevated maternal serum and placental inflammatory cytokines and a higher rate of placental inflammation. Lipopolysaccharide resulted in the features of APO and at the same time elevated MS-AFP. Maternal serum alpha-fetoprotein levels were significantly correlated to the evaluation parameters of APO. Lipopolysaccharide did not increase the expressions of AFP in fetal liver, maternal liver and placenta, but reduced the fetal serum AFP levels.

CONCLUSION

The phenomenon that elevated MS-AFP is associated with APO, which has been reported in human pregnancies, is observed in our rat model. Placental inflammation can be the potential cause linking the two manifestations together. Although the source of elevated MS-AFP is not identified, fetal blood circulation is suspected. Our study may provide an animal model for the future studies on this subject.