The relationship between oxidative stress and preeclampsia. The serum ischemia-modified albumin levels and thiol/disulfide homeostasis

Meta-analysis of changes in thiol-disulfide homeostasis during preeclampsia

The present study systematically assessed alterations in thiol-disulfide homeostasis among women with preeclampsia (PE) through meta-analysis. This was conducted as such changes are believed to be associated with the oxidative stress underlying this condition. A comprehensive search of Medline, Web of Science, and Embase databases was conducted from their inception until 22 March 2023, to identify studies comparing levels of native thiol, total thiol, and disulfide between pregnant women with PE and those without PE. Results were pooled using a random-effects model to account for study heterogeneity. The analysis included a total of 631 women diagnosed with PE and 668 healthy pregnant women, encompassing 13 case-control studies and 1 prospective study. Pooled outcomes revealed that women with PE had significantly lower blood levels of native thiol, (mean difference [MD] -51.42 umol/L; 95% confidence interval [CI] -79.75 to -23.10 umol/L; P < 0.001; I2 = 0% and total thiol (MD -65.56 umol/L; 95% CI -104.97 to -26.15 umol/L; P = 0.001; I2 = 0%) compared to the control group. In contrast, no significant difference was observed in blood disulfide levels between the two groups (MD -1.10 umol/L; 95% CI -4.41 to -2.21 umol/L; P = 0.51; I2 = 0%). Subgroup analyses indicated that the results were consistent across studies matched by gestational age and body mass index, as well as those with varying quality scores (P for subgroup differences all > 0.05). In conclusion, women with PE are associated with significantly reduced blood levels of native and total thiols but show no change in blood disulfide levels, suggesting a state of reduced antioxidants in PE.

Pravastatin Prevents Increases in Activity of Metalloproteinase-2 and Oxidative Stress, and Enhances Endothelium-Derived Nitric Oxide-Dependent Vasodilation in Gestational Hypertension

Pre-eclampsia (PE) is a hypertensive disorder of pregnancy and has been associated with placental growth restriction. The pre-eclamptic placenta releases free radicals to maternal circulation, thus increasing oxidative stress. An impaired redox state leads to reduction in circulating nitric oxide (NO) levels and activation of extracellular matrix metalloproteinases (MMPs). However, activation of MMPs induced by oxidative stress is still unclear in PE. Antioxidant effects have been demonstrated with the use of pravastatin. Therefore, we hypothesized that pravastatin protects against oxidative stress-induced activation of MMPs in a rat model of PE. The animals were divided into four groups: normotensive pregnant rats (Norm-Preg); pregnant rats treated with pravastatin (Norm-Preg + Prava); hypertensive pregnant rats (HTN-Preg); and hypertensive pregnant rats treated with pravastatin (HTN-Preg + Prava). The deoxycorticosterone acetate (DOCA) and sodium chloride (DOCA-salt) model was used to induce hypertension in pregnancy. Blood pressure, and fetal and placental parameters were recorded. The gelatinolytic activity of MMPs, NO metabolites and lipid peroxide levels were also determined. Endothelium function was also examined. Pravastatin attenuated maternal hypertension, prevented placental weight loss, increased NO metabolites, inhibited increases in lipid peroxide levels, and reduced the activity of MMP-2, and these effects were observed along with enhanced endothelium-derived NO-dependent vasodilation. The present results provide evidence that pravastatin protects against activation of MMP-2 induced by oxidative stress in pre-eclamptic rats. These findings may also involve improvement in endothelial function related to NO and antihypertensive effects of pravastatin, thus suggesting pravastatin as a therapeutic intervention for PE.

Evaluating Ischemia-Modified Albumin as an Early Biomarker for Hypertensive Disorders During Pregnancy: A Case-Control Study

Background Ischemia-modified albumin (IMA) is looked upon as a newer marker of myocardial ischemia. There is a paucity of literature however with regard to studies correlating levels of IMA in patients with hypertensive disorders of pregnancy. The present study therefore aimed at estimating the levels of IMA in patients with gestational hypertension and assessing its utility in predicting hypertensive disorders of pregnancy. Methods The present study was a hospital-based case-control study conducted in the Department of Biochemistry, All India Institute of Medical Sciences (AIIMS), Nagpur. IMA was estimated in 30 controls (Group I) and 20 cases of gestational hypertension (Group II) using a spectrophotometric assay detecting free unbound Cobalt left behind. The clinical data and lab results were presented as mean ± SD. Student's t-test was applied and Pearson's correlation coefficient was calculated. A value of p < 0.05 was taken as statistically significant. The ROC (Receiver Operator Characteristic) curve was used to establish the cut-off of serum IMA levels in pregnancy-induced hypertension (PIH). Results There was no significant difference in age and period of gestation (POG) at the time of sample collection between the groups. There was a significant difference in the systolic and diastolic blood pressures (BPs) of both groups. The mean level of serum IMA was significantly higher in cases of gestational hypertension (0.88 ± 0.14 absorbance units {ABSU}) as compared to controls (0.69 ± 0.08 ABSU) (p<0.001). On correlation analysis, the systolic and diastolic BPs were found to be highly positively correlated with serum IMA levels (p<0.001). ROC curve analysis suggested that at a cut-off of 0.73 ABSU, IMA has 85% sensitivity and 80% specificity for predicting gestational hypertension. Conclusion Statistically significant results of serum IMA levels obtained in gestational hypertension which falls on the lesser severe spectrum of the disease imply that serum IMA can be used for early diagnosis of gestational hypertension and impending Pre-eclampsia (PE) and Eclampsia.

The diagnostic potential of oxidative stress biomarkers for preeclampsia: systematic review and meta-analysis

Background

Preeclampsia is a multifactorial cardiovascular disorder of pregnancy. If left untreated, it can lead to severe maternal and fetal outcomes. Hence, timely diagnosis and management of preeclampsia are extremely important. Biomarkers of oxidative stress are associated with the pathogenesis of preeclampsia and therefore could be indicative of evolving preeclampsia and utilized for timely diagnosis. In this study, we conducted a systematic review and meta-analysis to determine the most reliable oxidative stress biomarkers in preeclampsia, based on their diagnostic sensitivities and specificities as well as their positive and negative predictive values.

Methods

A systematic search using PubMed, ScienceDirect, ResearchGate, and PLOS databases (1900 to March 2021) identified nine relevant studies including a total of 343 women with preeclampsia and 354 normotensive controls.

Results

Ischemia-modified albumin (IMA), uric acid (UA), and malondialdehyde (MDA) were associated with 3.38 (95% CI 2.23, 4.53), 3.05 (95% CI 2.39, 3.71), and 2.37 (95% CI 1.03, 3.70) odds ratios for preeclampsia diagnosis, respectively. The IMA showed the most promising diagnostic potential with the positive predictive ratio (PPV) of 0.852 (95% CI 0.728, 0.929) and negative predictive ratio (NPV) of 0.811 (95% CI 0.683, 0.890) for preeclampsia. Minor between-study heterogeneity was reported for these biomarkers (Higgins’ I² = 0–15.879%).

Conclusions

This systematic review and meta-analysis identified IMA, UA, and MDA as the most promising oxidative stress biomarkers associated with established preeclampsia. IMA as a biomarker of tissue damage exhibited the best diagnostic test accuracy. Thus, these oxidative stress biomarkers should be further explored in larger cohorts for preeclampsia diagnosis.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13293-022-00436-0.

Biomarkers of oxidative stress are related to the pathogenesis of preeclampsia and might be indicative of evolving preeclampsia and utilized for timely diagnosis and management of preeclampsia.

Systematic review and meta-analysis were conducted to evaluate the diagnostic accuracy of oxidative stress markers based on their diagnostic sensitivities and specificities.

Clinically relevant positive predictive values (PPVs) and negative predictive values (NPVs) were determined for each biomarker.

IMA, UA, and MDA were associated with 3.38, 3.05, and 2.37 odds ratios for preeclampsia onset.

IMA exhibited the most promising diagnostic potential with an average PPV of 0.852 and NPV of 0.811, respectively. Minor heterogeneity was reported for these biomarkers (Higgins’ I² = 0–15.879%).

These oxidative stress markers should be further explored in larger cohorts for preeclampsia diagnosis.

Diagnostic value of oxidative stress markers in patients presenting with primary dysmenorrhea to the emergency department

Background and Aim

Primary dysmenorrhea (PD) is a common presentation for emergency departments. This study investigates the diagnostic value of oxidative stress and ischemia markers in patients with PD.

Materials and Methods

The participants were classified into the PD group (patients with PD) and the control group (healthy volunteers). Thiol/Disulfide Homeostasis (TDH) parameters (Ds, Disulfide; NT, Native Thiol; TT, Total Thiol) and serum ischemia modified albumin (IMA) levels of the groups were measured. The Numeric Rating Scale (NRS) was used for pain assessment. Bivariate correlation analysis was performed to test the relationship between NRS and oxidative stress parameters. A P < 0.05 was considered significant.

Results

A total of 135 patients (PD group, n = 83; Control group, n = 52) were included in the study. PD group had statistically higher oxidant biomarkers (Ds level, Ds/NT ratio and Ds/TT ratio) and lower antioxidant biomarkers (NT/TT ratio) compared to the control group (p = 0.001; 0.003; 0.002, and 0.002, respectively). Serum IMA level in the PD group was higher than in the control group (P = 0.000). There was a positive correlation between IMA and NRS score (r = 0.342, P < 0.01), but no correlation was found between the other oxidative stress parameters and NRS.

Conclusions

PD is characterized by increased oxidative stress and ischemia in the endometrium, which can be detected by TDH parameters and serum IMA. NRS score in PD patients is positively correlated with serum IMA level, which suggests IMA level can be valuable to determine the severity of endometrial ischemia and pain in patients with PD.

Maternal Serum Levels of Zinc, Copper, and Thiols in Preeclampsia Patients: a Case-Control Study

Preeclampsia is one of the leading causes of maternal mortality-morbidity, and environmental factors act as the main driving force for the development of disease in genetically lean women. Trace element levels (zinc, copper) and thiol state (total, native thiol) may affect involved risk factors and play a role in the pathogenesis. The objective of our study is to assess trace element and thiol levels in patient and control groups. A total number of 88 pregnant women (in their third trimester) included 43 preeclampsia patients and 45 normotensive pregnant women as controls. The main findings of this study were the significantly elevated copper levels and decreased thiol levels (native and total thiols) in the patient group compared to controls (p < 0.05). Disulfide levels were not statistically different between the groups (p > 0.05). In patients, the predictive cutoff value of copper was 224 μg/dL and was 1.19 for the copper/native thiol ratio. Zinc levels were not statistically different between the two groups. Correlation analysis revealed no relationship between zinc-copper and zinc-total thiol levels in patients, while a positive correlation was evident in controls (zinc-copper, p < 0.05, r = 0.425, and zinc-total thiol levels, p < 0.05, r = 0.642). Patients had marginally high ALT and AST values in the normal range, and a significant difference was found between the two groups (p < 0.05). According to these results, elevated copper levels and decreased thiol levels may have a value for early prediction. The mechanisms that may be responsible for the altered element and thiol status have been discussed here in the context of oxidative stress.

Ischemia-Modified Albumin: Origins and Clinical Implications

Albumin is one of the most abundant proteins in the body of mammals: about 40% of its pool is located in the intravascular space and the remainder is found in the interstitial space. The content of this multifunctional protein in blood is about 60-65% of total plasma proteins. A decrease in its synthesis or changes of functional activity can destabilize oncotic blood pressure, cause a violation of transporting hormones, fatty acids, metals, and drugs. Albumin properties change under ischemic attacks associated with oxidative stress, production of reactive oxygen species, and acidosis. Under these conditions, ischemia-modified albumin (IMA) is generated that has a reduced metal-binding capacity, especially for transition metals, such as copper, nickel, and cobalt. The method of determining the cobalt-binding capability of HSA was initially proposed to evaluate IMA level and then licensed as an ACB test for routine clinical analysis for myocardial ischemia. Subsequent studies have shown the viability of the ACB test in diagnosing other diseases associated with the development of oxidative stress. This review examines recent data on IMA generation mechanisms, describes principles, advantages, and limitations of methods for evaluation of IMA levels, and provides detailed analysis of its use in diagnostic and monitoring therapeutic efficacy in different diseases.

Simultaneous Determination of Human Serum Albumin and Low-Molecular-Weight Thiols after Derivatization with Monobromobimane

Biothiols are extremely powerful antioxidants that protect cells against the effects of oxidative stress. They are also considered relevant disease biomarkers, specifically risk factors for cardiovascular disease. In this paper, a new procedure for the simultaneous determination of human serum albumin and low-molecular-weight thiols in plasma is described. The method is based on the pre-column derivatization of analytes with a thiol-specific fluorescence labeling reagent, monobromobimane, followed by separation and quantification through reversed-phase high-performance liquid chromatography with fluorescence detection (excitation, 378 nm; emission, 492 nm). Prior to the derivatization step, the oxidized thiols are converted to their reduced forms by reductive cleavage with sodium borohydride. Linearity in the detector response for total thiols was observed in the following ranges: 1.76–30.0 mg mL⁻¹ for human serum albumin, 0.29–5.0 nmol mL⁻¹ for α-lipoic acid, 1.16–35 nmol mL⁻¹ for glutathione, 9.83–450.0 nmol mL⁻¹ for cysteine, 0.55–40.0 nmol mL⁻¹ for homocysteine, 0.34–50.0 nmol mL⁻¹ for N-acetyl-L-cysteine, and 1.45–45.0 nmol mL⁻¹ for cysteinylglycine. Recovery values of 85.16–119.48% were recorded for all the analytes. The developed method is sensitive, repeatable, and linear within the expected ranges of total thiols. The devised procedure can be applied to plasma samples to monitor biochemical processes in various pathophysiological states.