An observational study of pro- and anti-angiogenic factors in hypertensive disorders of pregnancy in women of African ancestry

Abstract

Hypertensive disorders in pregnancy (HDPs) are the leading cause of maternal and perinatal deaths worldwide. Despite the widely reported multisystemic pathophysiology of pre-eclampsia and other HDPs, it is unknown whether these disorders represent a continuum or separate entities making clinical diagnosis a challenge. This study aimed to investigate angiogenic, metabolic and immunoregulatory specific profiles of hypertensive and gestationally matched normotensive pregnancies. A total of 200 pregnancies from a regional hospital in South Africa, via convenience sampling, were quantitatively analysed for circulating sFlt-1; PlGF; VEGF; sENG; PAPP-A; PP13; ADAMTS 12; TGF-β1 in maternal serum samples using ELISA technique. Serum protein markers TGF-β1, sENG and PAPP-A were significantly increased (p < .05) in early-onset pre-eclampsia vs. NG1 groups. sFlt-1 was significantly higher in late-onset pre-eclampsia vs NG2 groups. The GH group showed a significant increase in TGF-β1 and PAPP-A vs. NG1 counterpart. ADAMTS12 and sENG were significantly lower in gestational hypertension vs. early-onset pre-eclampsia. No significant differences were seen in PlGF, VEGF and PP13 levels across the groups. These changes show the HDP spectrum has distinct characteristics on the angiogenic profile. Based on these results, further validation of diagnostic and prognostic biomarkers of pre-eclampsia and gestational hypertension is warranted.

Impact statement

• What is already known on this subject? Hypertensive pregnancy disorders are a public health problem with adverse effects on both mother and neonate. The elusive pathogenesis of this syndrome combined with the late prevalence of symptoms leaves clinicians with a myriad of theories and indefinite treatments. The investigation into conventional anti-/angiogenic factors has been extensively studied in pre-eclampsia patients only. The overlapping clinical presentation of pre-eclampsia and gestational hypertension further complicates the diagnosis of disorders.

• What do the results of this study add? The investigation of novel angiogenic, metabolic and inflammatory markers will firstly contribute to generating a database for researchers both nationally and internationally. This combinatory triad of markers will assist in elucidating and differentiating between early- and late-onset preeclampsia versus gestational hypertension. The results of our cohort study suggest possible early diagnostic markers for pre-eclampsia and gestational hypertension.

• What are the implications of these findings for clinical practice and/or further research? Research in this area will contribute to an improvement in early disease management which will ultimately lead to a reduction in health care costs and mortality rate locally and globally. It will also enforce diagnostic and prognostic markers for hypertensive pregnancy diseases and warrant further investigation into the proteins primarily involved in the trophoblastic invasion. This will then clarify whether these two closely related hypertensive disorders represent a continuum or two separate entities.

Keywords:

• Angiogenic factors
• gestational age
• gestational hypertension
• pre-eclampsia

Acknowledgements

Recognition to Dr Kaminee Maduray and Miss Z Mkhize for the collection of the blood samples and Mrs Cassandra Subiah for editing.

Author contributions

N.S. and I.M. conceived and designed the project and experiments; N.S. and A.K. performed the experiments; N.S. and I.M. contributed reagents and materials; N.S., A.K., I.M. and J.M. wrote the manuscript; all the authors have read and approved the manuscript.

Disclosure statement

The authors report no conflicts of interest in this work.

Data availability statement

All the data related to the manuscript is presented in tables and extra raw data is available.

Additional information

Funding

This work was supported by the South African National Research Foundation [Thuthuka grant No: TTK180410319237].