|Year : 2020 | Volume
| Issue : 1 | Page : 11-16
Serum levels of tumor necrosis factor- α and interleukin -10, and their clinical correlates in women with pre-eclampsia/eclampsia in Ahmadu Bello University Teaching Hospital
Zulaihatu Sarkin-Pawa1, Muhammad Adogie Abdul1, Bolale O P Musa2, Jim Monday Banda3, Umma Suleiman Bawa1, Hajara Umaru-Sule1
1 Department of Obstetrics and Gynaecology, Ahmadu Bello University, Zaria, Nigeria
2 Department of Medicine, Immunology Unit, Ahmadu Bello University, Zaria, Nigeria
3 Department of Medical Laboratory Science, University of Jos, Jos, Nigeria
|Date of Submission||15-Mar-2020|
|Date of Acceptance||05-Jun-2020|
|Date of Web Publication||06-May-2021|
Dr. Zulaihatu Sarkin-Pawa
Department of Obstetrics and Gynaecology, Ahmadu Bello University, Zaria
Source of Support: None, Conflict of Interest: None
Background: Pre-eclampsia is a pregnancy-specific disorder characterized by the onset of hypertension and proteinuria after the 20th week of gestation. It is characterized by an exaggerated maternal inflammatory response with a preponderance of cell-mediated immune response. Tumor necrosis factor-alpha (TNF-α) is a pro-inflammatory cytokine that induces apoptosis and restrains differentiation. Defective trophoblastic invasion is now identified as the key etiology of pre-eclampsia. The objective of this study was to determine the serum levels TNF-α and interleukin 10 (IL-10) in women with pre-eclampsia/eclampsia and the relationship between these cytokines and the severity of the disease.
Patients and Method: This was a case-control study carried out in Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Forty-eight patients with a diagnosis of pre-eclampsia/eclampsia were recruited as cases. The diagnosis was according to the International Society for the Study of Hypertension in Pregnancy (ISSHP) criteria. For each case, a healthy pregnant control was selected, after matching for age, gestational age, and parity. Blood samples were taken and assayed for TNF-α and IL 10 using enzyme-linked immunosorbent assay. Data were analyzed using SPSS v 20. A P value <0.05 was considered statistically significant.
Results: The prevalence of pre-eclampsia/eclampsia in ABUTH Zaria is 5.1%. Nulliparous women constituted 65.9% of the patients. Thirty-five percent of the women were between 20 and 24 years of age. The mean serum levels of TNF-α in women with pre-eclampsia/ eclampsia and controls were 294.8 ± 146 pg/mL and 176 ± 35.5 pg/mL, respectively. The mean serum levels of IL-10 in patients and controls with pre-eclampsia were 13.9 ± 5.7 pg/mL and 33.0 ± 11.0 pg/mL, respectively. The levels of TNF-α correlated positively with the severity of the disease. The serum levels of IL-10 did not correlate with disease severity.
Conclusion: The prevalence of pre-eclampsia/eclampsia is high in ABUTH. The disease is characterized by an exaggerated inflammatory response in women in Zaria. Use of anti- TNF-α drugs may possibly have a role in the prevention of pre-eclampsia.
Keywords: Cytokines, TNF-α, IL-10, pre-eclampsia, eclampsia
|How to cite this article:|
Sarkin-Pawa Z, Abdul MA, Musa BO, Banda JM, Bawa US, Umaru-Sule H. Serum levels of tumor necrosis factor- α and interleukin -10, and their clinical correlates in women with pre-eclampsia/eclampsia in Ahmadu Bello University Teaching Hospital. Arch Int Surg 2020;10:11-6
|How to cite this URL:|
Sarkin-Pawa Z, Abdul MA, Musa BO, Banda JM, Bawa US, Umaru-Sule H. Serum levels of tumor necrosis factor- α and interleukin -10, and their clinical correlates in women with pre-eclampsia/eclampsia in Ahmadu Bello University Teaching Hospital. Arch Int Surg [serial online] 2020 [cited 2021 Jun 16];10:11-6. Available from: https://www.archintsurg.org/text.asp?2020/10/1/11/315392
| Introduction|| |
Pre-eclampsia (PE) is a pregnancy-specific disorder characterized by the new onset of hypertension accompanied by proteinuria, evidence of maternal organ damage, or uteroplacental damage occurring in the second half of pregnancy. It is a common obstetric condition that is a leading cause of both maternal and perinatal mortality and morbidity worldwide. Eclampsia (E) is a terminal complication of the disease, defined as the occurrence of generalized clonic tonic convulsions in patients with pre-eclampsia, in the absence of any other identifiable cause.
Many theories have been postulated on the etiology of pre-eclampsia. All of these theories converge into a common pathophysiological denominator: Endothelial dysfunction. Excessive maternal inflammatory response, perhaps targeted against foreign fetal antigens, results in an impaired trophoblastic invasion with defective spiral artery remodeling. This leads to high resistance vessels with reduced perfusion. Several cytokines produced at the fetomaternal interphase have an impact on trophoblast invasion.
In a normal pregnancy, there is mild inflammation with a shift towards T-helper 2-type immune response. In pre-eclampsia, there is an exaggeration of maternal immune response with Th1 preponderance.,, Deficiency of interleukin-10 (IL-10) may contribute to this enhanced inflammatory response towards the trophoblast elicited by tumor necrosis factor-α (TNF-α) and interferon ɤ. Trophoblasts that are subjected to a high rate of apoptosis are hampered in their invasive capacity leading to a defective transformation of spiral arteries. This results in hypoxia, thrombosis, and infarction of the placenta. This infarction leads to increasing amounts of placental fragments and cytokines into the maternal circulation and an exaggerated systemic endothelial activation as identified in pre-eclampsia (PE).,
Currently, the determination of serum levels of cytokines especially TNF-alpha may help in the prediction of pre-eclampsia. Certain anti-TNF drugs are already in use and may have potential benefits in the prevention of the disease, especially in women with recurrent or early-onset PE.
The aim of the study was to determine the serum levels of TNF-α and IL-10 in patients with pre-eclampsia/eclampsia in Ahmadu Bello University Teaching Hospital, Zaria with a view to establish the relationship between these cytokines and the severity of the disease.
| Patients and Method|| |
It was a case-control study. Women with the diagnosis of pre-eclampsia or eclampsia were considered as cases. For this study, significant hypertension and proteinuria were as defined by the International Society for the Study of Hypertension in Pregnancy (ISSHP). The inclusion criteria were consenting pregnant women with a diagnosis of pre-eclampsia or eclampsia at a gestational age of 28 weeks and above, or women in the first one week postpartum.
Women with pyrexia of >38°C, placental abruption, multifetal gestation, chronic hypertension, diabetes mellitus, fetal congenital anomaly, HIV, history of smoking, and renal disease were excluded.
A systematic sampling of patients was done to select the cases. Every second patient with a diagnosis of pre-eclampsia/eclampsia was selected after meeting the inclusion criteria until the sample size was achieved. Consenting healthy pregnant women matched for age, gestational, and parity were recruited in the antenatal clinic and used as the controls.
The patient or relatives of unconscious patients were counseled and written consent to participate in the study was obtained. Data were collected using a proforma designed for the study.
The blood pressure of each patient was taken using a mercury sphygmomanometer with appropriate cuff size and with the arm at the level of the heart. Patients were placed in the supine position with a left lateral tilt. The 5th Korotkoff's sound was taken as the cut-off for the diastolic pressure.
Urinalysis was done on a clean catch urine specimen with Combi-9® strip for proteinuria. Ten milliliters of venous blood was collected by venipuncture from the antecubital vein after skin preparation with methylated spirit. Sterile 21 G disposable hypodermic needles were used for the venepuncture. All blood samples from the patient group were taken once and before the commencement of treatment. Samples from controls were also taken once after matching. The blood collected was transferred into plain bottles containing 50 μL of aprotinin (Trasylol™) to inhibit the degradation of the cytokines. The blood was allowed to clot and retract. The specimen was centrifuged at 4000 revs/min to separate the serum from the cells. The serum was drawn into sample bottles containing 2 drops of aprotinin and stored in the freezer at -20°C until the time of analysis.
Analysis for serum TNF-α and Il-10 was done using commercial high sensitivity, specific Enzyme-Linked Immunosorbent Assay (ELISA) kits (Ray Biotech USA) following the protocol outlined. All frozen samples were thawed once at the time of analysis.
The data obtained were analyzed using SPSS version 20 for windows. Results were presented using tables and charts and figures. Continuous variables were expressed in terms of mean and standard deviations. Ordinal variables were presented in percentages or proportions. Serum levels of TNF-α and Il-10 obtained from patients were compared with those of controls using student's t-test. Correlation of serum levels of TNF-α and IL-10 with the severity of disease was carried out using Analysis of Variance (ANOVA). A P value of less than 0.05 was considered statistically significant.
Ethical approval for the study was obtained from the Ethical and Scientific Research Committee of the institution. Written consent was obtained from patients or their relatives. Confidentiality was maintained. Nonconsenting pregnant women still received due care. The investigations were at no cost to the patients.
| Results|| |
From January to December 2016, a total of 1991 deliveries were conducted. One hundred and two of the parturients had pre-eclampsia/eclampsia. This gives a prevalence rate of 5.1%. This is shown in [Table 1].
|Table 1: Prevalence of Pre-eclampsia/eclampsia among parturients in ABUTH in 2016|
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The sociodemographic characteristics of patients and controls are shown in [Table 2]. The mean age of the cases was 24.7 ± 6.4 years with a range of 17 to 39 years. All the women enrolled were married. Parity distribution among cases and controls is shown in [Figure 1]. Forty-one (85.4%) of the cases had pre-eclampsia while 7 (14.6%) had eclampsia. Thirty-four (64.6%) of the cases were booked. All the controls were booked as shown in [Table 3].
|Figure 1: Parity distribution among cases and controls in Ahmadu bello university teaching hospital (ABUTH) 2016|
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The majority of the cases of pre-eclampsia (73.2%) were diagnosed antepartum while most of the cases of eclampsia were diagnosed intrapartum (85.7%). [Figure 2],[Figure 3] show the time of diagnosis.
The mean serum levels of TNF-α (± SD) in cases and controls were 294.8 (±146) pg/ml and 176.0 (35.5) pg/mL, respectively. The mean serum levels of IL-10in cases and control group were 13.9 (± 5.7) pg/mL and 33.0 (± 11.0) pg/mL, respectively. Using the student t-test, there was a statistical difference in the mean values of TNF-α and IL-10 between cases and controls [Table 4].
A statistically significant difference was found in the mean serum TNF-α among cases with mild pre-eclampsia, severe pre-eclampsia, and eclampsia [Table 5]. This was not the case for IL-10 as there was no statistically significant difference in relation to the severity of the disease. Using Pearson's correlation coefficient, a positive but weak relationship was found between the serum levels of TNF-α and the severity of systolic hypertension. This relationship was not statistically significant. There was a moderate positive and statistically significant correlation between diastolic blood pressure and TNF-α. IL-10 was found to correlate negatively with the severity of systolic hypertension [Table 6]
|Table 6: Relationship Between Mean Serum Levels of TNF-α, IL-10 and Severity of Hypertension|
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The TNF-α - IL-10 ratio increased from 16.5 in mild pre-eclampsia to 19.07 in severe pre-eclampsia and 23.3 in eclampsia [Table 7]. This difference is statistically significant using Pearson's correlation coefficient.
| Discussion|| |
The incidence of pre-eclampsia/eclampsia of 5.1% in this study is higher than the national average of 3.12%. The difference may be accounted for by the fact that this study was carried out in a tertiary hospital that receives referrals from surrounding primary and secondary facilities. The reasons for most of these referrals are intensive care unit (ICU) and neonatal intensive care (NICU) facilities.
The mean serum levels of TNF-α were found to be higher in cases than in the control group. This is in keeping with findings reported by Ahmed et al. in Egypt and Udenze et al. in Lagos. The mean serum levels of IL10 are higher in the control group than in the pre-eclampsia/eclampsia group. This is consistent with the finding of Vitaratus et al. in Greece and Khazaei-Koohpar et al. in Iran. Contradictory findings were reported by Bakheit et al. in Sudan where serum levels of IL-10 were higher in PE women and Jonsson et al. in Sweden observed no difference. These differences could be related to sampling in the different stages of pregnancy. Pre-eclampsia as an inflammatory condition starts from the first steps of placentation. Some patients may have been on other medications such as dexamethasone, which is known to reduce inflammation. Normotensive pregnancy evolves with high levels of the regulatory cytokineIL-10. In pre-eclampsia/eclampsia, therefore, there is a defect in the counter- regulatory inflammatory processes.
The findings of this study showed the highest levels of TNF-α in eclamptic patients followed by severe pre-eclampsia. This is similar to reports from India by Tayal D, et al. and from Turkey by Conaruc N, et al. This difference is statistically significant with the increasing severity of the disease. This may be explained by the fact that in eclampsia, there is cerebral hypoxia, which may lead to further release of mediators of inflammation. There was, however, no statistically significant difference in the serum levels of IL-10 in relation to the severity of the disease. This is similar to the report by Lewis and coworkers. Borekci et al. in Turkey, however, reported a contrary finding. The latter study used all consecutive patients and used the median values for statistical analysis. The TNF-α-IL-10 ratio increased significantly with the severity of disease in this study, which is similar to reports from Brazil by Pinheiro et al. and Kuwait by Azizieh et al. This is suggestive of a maternal proinflammatory cytokine bias.
| Conclusion|| |
The prevalence of pre-eclampsia/eclampsia at Ahmadu Bello University Teaching Hospital is high. The mean serum levels of TNF-α are increased in Nigerian women with pre-eclampsia and eclampsia. The disease is characterized by an exaggerated inflammatory response. The TNF-α-a- IL-10 10 ratio has the potential to be a marker for the severity of the disease.
In the last few years, anti-TNF drugs have been developed and used for a variety of conditions such as rheumatoid arthritis. They have, however, not been tested for pre-eclampsia because pregnant and breastfeeding women are largely exempted from clinical trials. Studies in mice have shown that eternacept, an anti-TNF drug, prevents fetal hypoxia and neuroproliferative defects in the fetal brain by targeting the placental TNF. This area remains to be further researched in humans.
The case-control design gives strength to this study. Matching for age, parity, and gestational age helped in the elimination of confounders. However, being a hospital-based study, the prevalence of pre-eclampsia cannot be generalized to the population. It is also limited by the small sample size. ELISA method used for assay measures both biologically active and inactive forms of the cytokines.
Larger multicenter studies on these cytokines are required for generalization. Longitudinal studies in women starting from the first trimester will give an idea of the cut-off predictive value of TNF-α in the development of pre-eclampsia.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]