Hepcidin Levels and Related Biochemical Parameters in Pregnant Women with Preeclampsia

By Naim Uzun¹, Adem Keskin²

Affiliations

1. Department of Clinical Pharmacy, Faculty of Pharmacy, Agri Ibrahim Cecen University, Agri, Turkiye
2. Department of Medical Biochemistry, Faculty of Medicine, Aydin Adnan Menderes University, Aydin, Turkiye

doi: 10.29271/jcpsp.2025.08.997

ABSTRACT
Objective: To evaluate hepcidin levels and related biochemical parameters in healthy pregnant women and those with preeclampsia.
Study Design: Analytical study.
Place and Duration of the Study: Erzurum Nene Hatun Maternity and Child Diseases Hospital, Erzurum, Turkiye, from October to December 2023.
Methodology: Sixty-two pregnant females with preeclampsia and twenty-five healthy pregnant females were included in this research. Hepcidin and biochemical parameters were analysed using spectrophotometric methods. The obtained data from pregnant women with preeclampsia and healthy pregnant women were then compared by the independent samples t-test. The relationship between hepcidin and biochemical parameters was analysed by the Pearson’s correlation test.
Results: The values of hepcidin in the two groups did not differ significantly (10.78 ± 7.63 ng/ml in eclamptic patients and 8.95 ± 5.77 ng/ml in control group, p = 0.28). Ferritin values of the patient group were lower than those of the control group. C-reactive protein (CRP) and superoxide dismutase (SOD) values of the patient group were higher than those of the control group. Hepcidin values of the control group determined a positive correlation with transferrin (correlation coefficient [cc] = 0.466, p = 0.019), transferrin receptor (cc = 0.620, p = 0.001), CRP (cc = 0.893, p <0.001), and SOD (cc = 0.631, p = 0.001) levels. Similarly, hepcidin levels of the patient group determined a positive correlation with transferrin, (cc = 0.747, p <0.001), TfR (cc = 0.772, p <0.001), CRP (cc = 0.351, p = 0.006), and SOD activity (cc = 0.779, p <0.001) levels. In addition, the hepcidin levels of the patient group showed a positive correlation with tumour necrosis factor-alpha levels (cc = 0.36, p = 0.012) and a negative correlation with ferritin levels (cc = -0.25, p = 0.04).
Conclusion: High hepcidin levels are indicators of preeclampsia which should not be ignored. Particular attention should be paid to hepcidin values if they are above the reference values.

Key Words: Hepcidin, Malondialdehyde, Preeclampsia, Superoxide dismutase.

INTRODUCTION

Preeclampsia, one of the most feared complications of pregnancy, usually occurs in the third trimester and is characterised by proteinuria and hypertension.¹ Preeclampsia, which can cause maternal and perinatal morbidity or mortality, affects 2-8% of pregnancies worldwide. Proteinuria and hypertension are the main characteristics of the disease. However, it can also cause systemic organ dysfunctions.² Preeclampsia in early pregnancy is associated with placentation defects, whereas pre- eclampsia in the last weeks of pregnancy is associated with a mismatch between maternal perfusion, susceptibility to maternal cardiovascular disease, and feto-placental demands.³

Preeclampsia causes syncytiotrophoblast stress and inc-reases the shedding of extracellular vesicles, leading to the accumulation of extracellular haemoglobin and its metabolites, haem and iron.⁴ Excessive iron accumulation and lipid peroxidation promote ferroptosis—a type of cell death.⁵ Ferroptosis mediates the pathophysiology of preeclampsia. Oxidative stress, caused by lipid peroxidation, plays a significant role in the progression and development of pre- eclampsia.⁶

Hepcidin is an iron-regulating hormone that determines total body iron content and plasma iron levels. Hepcidin functions by regulating the activity of ferroportin, responsible for transferring iron from iron stores to plasma and facilitating the absorption of iron in the intestine.⁷ Abnormally elevated hepcidin levels cause systemic iron deficiency and/or iron-limited erythropoiesis. Dysregulation of hepcidin levels is also observed in many diseases caused by iron overload. Abnormal iron metabolism resulting from dysregulated hepcidine levels is an underlying factor leading to the patho- physiology of many diseases.⁸ In the second or third trimesters of a healthy pregnancy, the hepcidin concentration is suppressed, and iron enters the circulation more easily. An inappropriate elevation of hepcidin levels during pregnancy may impair the effectiveness of iron supplementation and reduce the availability of iron for placental transfer.⁹

Pregnancy involves metabolic, physiological, and hormonal changes, which can cause various imbalances. Among these, preeclampsia is one of the significant complications of pregnancy. Excessive iron accumulation is associated with irre-gularities in hepcidin levels and in many diseases. The aim of this study was to investigate hepcidin levels in healthy pregnant women and those with preeclampsia. In addition, it aimed to evaluate the relationship between hepcidin levels and biochemical parameters, such as malondialdehyde, an indicator of lipid peroxidation; superoxide dismutase, an antioxidant enzyme; iron profile parameters; some inflammation parameters; and haemoglobin in two different groups of pregnant women.

METHODOLOGY

Ethical approval was obtained from the Ethics Committee of Non-Interventional Clinical Research Ethics at the Ataturk University, Medical Faculty, Erzurum, Turkiye (Approval No: 25.06.15.5/14). The sample size was determined using the G*Power 3.1.9.7 power analysis programme. The inclusion criteria for the patient group were as follows: Patients diagnosed with preeclampsia, aged between 18-45 years, 24-36 weeks pregnant, and without any other health problems. Pre- eclampsia is defined as new-onset hypertension (≥140/90 mmHg) accompanied by proteinuria (≥300 mg / 24 hours) after 20 weeks of pregnancy.¹ The inclusion criteria for the control group were being within the same age and gestational age range, and having no other health problems. Pregnant women with other health issues or pregnancy complications other than the diagnosis of preeclampsia were excluded from the study. Additionally, written informed consent was obtained from all the participants, and those who did not give consent were excluded from the study.

All the blood samples were collected at the Erzurum Nene Hatun Maternity and Children's Hospital, Erzurum, Turkiye, by trained nurses under the supervision of the research team. Hepcidin, iron, ferritin, transferrin, transferrin receptor (TfR), tumour necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA) levels, and SOD activity were analysed from serum samples, using spectrophotometric methods. The Nano Drop™ 2000/2000c Spectrophotometer device was used for the spectrophotometric method. The kits used for analysis were obtained from Abcam. Haemoglobin and C- reactive protein (CRP) levels were obtained from the hospital automation system.

SPSS version 22 for Windows (IBM, New York, USA) was utilised for statistical data analysis. Continuous variables uncovered from the research were presented as X ± SD (mean ± standard deviation). And p-values were deemed statistically significant if they were less than 0.05. Homogeneity of variance was tested with the Levene's test. Continuous variables of the groups were compared using the independent samples t-test. The relationship between hepcidin levels and other biochemical parameters with in each group was analysed by the Pearson’s correlation  test.

RESULTS

The mean age of the patient group incorporated into the research was 27.49 ± 6.97 years, while the mean age of the control group was 27.68 ± 4.78 years. The mean gesta- tional age of the patient group was 34.53 ± 2.28 weeks, while the mean gestational age of the control group was 33.84 ± 1.84 weeks. The mean gestational ages and mean ages of the two groups did not significantly differ from one another. Laboratory findings of the control and patient groups are presented in Table I.

Ferritin levels of the patient group were determined to be lower than those of the control group. CRP and SOD activity levels of the patient group were determined to be higher than those of the control group. No statistical difference was detected between the groups in terms of other laboratory findings  upon  analysis  (Table I).

Hepcidin  levels of the  control  group  showed  a  positive correlation  with  transferrin (correlation coefficient [cc] = 0.466, p = 0.019), TfR (cc = 0.620, p = 0.001), CRP (cc = 0.893, p <0.001), and SOD (cc = 0.631, p = 0.001) levels, but did not correlate with other parameters. Similarly, hepcidin levels of the patient group showed a positive correlation with transferrin (cc = 0.747, p <0.001), TfR (cc = 0.772, p <0.001), CRP (cc = 0.351, p = 0.006), and SOD activity (cc = 0.779, p <0.001) levels. Additionally, hepcidin levels of the patient group showed a positive correlation with TNF-α levels (cc = 0.364, p = 0.012) and a negative correlation with ferritin levels (cc = -0.254, p = 0.046), but were not correlated with other parameters.
 

Table   I:   Laboratory   findings   of   the   groups.

Parameters	Patient (n = 62)	Control (n = 25)	p-values*
Hepcidin (ng/mL)	10.78 ± 7.63	8.95 ± 5.77	0.284
Iron (µM)	7.93 ± 5.55	7.18 ± 4.19	0.545
Ferritin (ng/ml)	6.35 ± 4.37	8.72 ± 4.29	0.024
Transferrin (ng/ml)	4.88 ± 2.03	4.23 ± 1.67	0.127
Transferrin receptor (pg/ml)	446.99 ± 185.10	367.27 ± 165.95	0.065
Haemoglobin (g/dl)	11.96 ± 1.91	12.62 ± 1.61	0.133
C-reactive protein (mg/L)	27.82 ± 31.54	13.19 ± 7.95	0.001
Interleukin-6 (pg/ml)	95.98 ± 165.44	75.81 ± 94.30	0.569
Tumour necrosis factor-alpha (pg/ml)	10.64 ± 8.95	15.12 ± 9.43	0.051
Superoxide dismutase (ng/ml)	28.76 ± 12.36	23.05 ± 8.33	0.015
Malondialdehyde (ng/ml)	24.59 ± 13.61	19.65 ± 16.46	0.153
*Independent samples t-test.

DISCUSSION

The primary methods for the clinical diagnosis of preeclampsia include proteinuria, high blood pressure, and ultrasonographic changes in uterine arterial flow. Early diagnosis and risk assessment are wise approaches to reduce feto-maternal morbidity. Although several studies report a potential relationship between hepcidin values and the early diagnosis of pre- eclampsia, the result remains conflicting.¹⁰

A recent study noted that hepcidin values were higher in pregnant females with preeclampsia than in healthy pregnant women. In addition, it was noted that hepcidin levels of pregnant women with poor foetal outcomes were higher than those of pregnant women with good foetal outcomes.¹¹ A more recent study reported that iron status and hepcidin levels were similar between pregnant females with preeclampsia and healthy pregnant females.¹² Another research highlighted that there was no significant difference in hepcidin levels of pregnant females with preeclampsia compared to the control group of the same gestational age.¹³

In a study investigating the normal reference range for serum hepcidin, the reference range for women was found to be 3.44–24.78 ng/mL.¹⁴ A study investigating high hepcidin levels in pregnant women with preeclampsia stated that iron supplementation may cause endothelial dysfunction and oxidative stress. Therefore, high hepcidin levels can be considered as a protective mechanism to combat cytotoxicity caused by iron overload.¹⁵ In this study, hepcidin levels did not differ between pregnant females with preeclampsia and healthy pregnant females. The mean hepcidin levels in pregnant women were within the reference range. Additionally, iron levels did not differ between the pregnant groups, and the mean iron levels remained below reference values.

Proteomic analysis of samples from pregnant women with pre- eclampsia revealed low levels of ferritin light chains, which are believed to trigger ferroptosis, thereby leading to the development of preeclampsia.¹⁶ In this study, ferritin levels of pregnant females with preeclampsia were lower than those of healthy pregnant females. While ferritin levels of pregnant women with preeclampsia were negatively correlated with hepcidin levels, it was not correlated with those of healthy pregnant women.

In the pathogenesis of preeclampsia, TNF-α expression increases the number of microvascular endothelial cells.¹⁷ On the other hand, a meta-analysis evaluating nonparametric data reported increased maternal circulating levels of IL-6 and TNF-α in pregnant females with preeclampsia.¹⁸ In this study, TNF-α and IL-6 values were not different between the groups. While the TNF-α levels of pregnant women with preeclampsia were positively correlated with hepcidin levels, it was not correlated with healthy pregnant females.

Higher MDA values are observed in preeclampsia, where oxidative stress plays a crucial role in its pathogenesis.¹⁹ On the other hand, antioxidant enzymes (SOD) are used in response to the increased oxidant state with high MDA levels.²⁰ In this study, although MDA levels were higher in pregnant females with pre- eclampsia, no statistical difference was detected between the groups. In addition, SOD values were higher in pregnant females with preeclampsia than in healthy pregnant women. This suggests that the level of the antioxidant enzyme system increases to tolerate increasing MDA levels.

This study is a single-centre study, and the limited sample size can be considered a limitation. However, it can be used as a reference for future multicentre studies with larger samples.

CONCLUSION

Although hepcidin levels are not decisive in distinguishing pre- eclamptic pregnant women from healthy pregnant women, they should not be ignored in this multifactorial disease, especially when they are above the reference values. In individuals receiving iron supplements or with genetic predisposition, monitoring hepcidin levels in the early stages of pregnancy may contribute to risk assessment and disease management.

ETHICAL  APPROVAL:
Ethical approval was obtained from the Ethics Committee of Non-Interventional Clinical Research Ethics at the Ataturk University, Medical Faculty, Erzurum, Turkiye (Approval No. 25.06.15.5/14).

PATIENTS’  CONSENT:
Informed consent was obtained from all the participants before inclusion in the study.

COMPETING  INTEREST:
The authors declared no conflict of interest.

AUTHORS’  CONTRIBUTION:
NU: Conception, design of the study, creating the study plan, acquisition, analysis, and interpretation of data, and writing of the manuscript.
AK: Design of the work, data processing, and critical revision of the manuscript.
Both authors approved the final version of the manuscript to be published.
 

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