Serum endocan concentration in women with pre-eclampsia

Endocan: A Key Player of Cardiovascular Disease

Endothelial dysfunction is considered to be an early change in atherosclerosis. Endocan, also known as endothelial cell specific molecule-1, is a soluble proteoglycan mainly secreted by endothelial cells. Inflammatory factors such as IL-1β and TNF-α can up regulate the expression of endocan and then affect the expression of cell adhesion molecules, such as ICAM-1 and VCAM-1, which play an important role in promoting leukocyte migration and inflammatory response. Elevated plasma levels of endocan may reflect endothelial activation and dysfunction, and is considered to be a potential immuno-inflammatory marker that may be related to cardiovascular disease. In the case of hypertension, diabetes, angina pectoris and acute myocardial infarction, the increase or decrease of serum endocan levels is of great significance. Here, we reviewed the current research on endocan, and emphasis its possible clinical value as a prognostic marker of cardiovascular disease. Endocan may be a useful biomarker for the prognosis of cardiovascular disease, but more research is needed on its mechanism of action.

Endothelial Dysfunction in Pregnancy Complications

The endothelium, which constitutes the inner layer of blood vessels and lymphatic structures, plays an important role in various physiological functions. Alterations in structure, integrity and function of the endothelial layer during pregnancy have been associated with numerous gestational complications, including clinically significant disorders, such as preeclampsia, fetal growth restriction, and diabetes. While numerous experimental studies have focused on establishing the role of endothelial dysfunction in pathophysiology of these gestational complications, their mechanisms remain unknown. Numerous biomarkers of endothelial dysfunction have been proposed, together with the mechanisms by which they relate to individual gestational complications. However, more studies are required to determine clinically relevant markers specific to a gestational complication of interest, as currently most of them present a significant overlap. Although the independent diagnostic value of such markers remains to be insufficient for implementation in standard clinical practice at the moment, inclusion of certain markers in predictive multifactorial models can improve their prognostic value. The future of the research in this field lies in the fine tuning of the clinical markers to be used, as well as identifying possible therapeutic techniques to prevent or reverse endothelial damage.

Comparison of the maternal serum endocan levels in preterm premature rupture of membrane and normal pregnancy

OBJECTIVE

Endocan is a novel marker of endothelial inflammation. In this study, we aimed to show whether there was a significant difference between the endocan levels of pregnant women with and without preterm premature rupture of membranes (PPROM and non-PPROM). Also, we aimed to find a relation between endocan levels and the latent period.

MATERIAL AND METHODS

Pregnant women with PPROM between 28 and 34 weeks of gestation and those without PPROM with similar gestational weeks were included in the study. A total of 88 pregnant women, 44 with PROM and 44 healthy pregnancies, were evaluated. Demographic and obstetric features, leukocyte, and endocan levels of the study and control groups were compared.

RESULTS

The demographic features and obstetric history of both groups were similar. The mean leukocyte and endocan levels of the study group were higher than in the control group (p < 0.001 and 0.029, respectively). The leukocyte level was the only independent factor predicting PPROM after multivariate logistic regression analysis.

CONCLUSION

Although the endocan levels were higher in patients with PPROM, multivariate analysis showed that the only independent predictive factor was the leukocyte level.

Plasma Endocan Levels in Early and Late-Onset Preeclampsia

Preeclampsia (PE) may represent an inflammatory process. Endocan (ESM-1) is a marker of endothelial inflammation. We compared plasma endocan levels between PE and control groups and between early and late-onset PE. Study design: Maternal plasma endocan levels were measured in 41 preeclampsia (PE) pregnancies - 25 early-onset (<34 weeks); 16 late-onset (≥34 weeks), and 37 non-complicated pregnancies (22 matched with early-onset PE, 15 with late onset). Results: There was no significant differences between plasma endocan levels of patients with PE and control group (468.8(IQR: 169.7)ng/L vs 462.4(IQR: 321.1)ng/L, p > 0.05), between early and late-onset PE (458.8(221.8)ng/L vs 469.8(122.6)ng/L, p > 0.05), between early-onset PE and corresponding control group (458.8(221.8)ng/L vs 506.2(1481.9)ng/L, p > 0.05), or late-onset PE and corresponding control group (469.8(122.6)ng/L vs 451.0(85.1)ng/L, p > 0.05). Conclusion: There was no significant difference between endocan levels of early or late-onset PE compared with their corresponding control groups, nor between early and late-onset preeclampsia groups.

Maternal serum endothelial cell-specific molecule-1 level and its correlation with severity of early-onset preeclampsia

Preeclampsia (PE), the primary pathology of which is endothelial cell (EC) dysfunction, has long-lasting effects such as cardiovascular disease. Therefore, it was decided to investigate the maternal serum concentrations of EC-specific molecule-1 in patients with early-onset preeclampsia (E-PE). This study was conducted on 33 pregnant women with E-PE and 35 healthy pregnant women matched for gestational age. EC-specific molecule-1 level was measured using a commercially available enzyme-linked immunosorbent assay kit. The mean EC-specific molecule-1 concentrations were not significantly different between the groups (651.7 ± 632.2 pg/mL vs. 425.9 ± 263.0 pg/mL, p=.056). Among women with E-PE, the median EC-specific molecule-1 concentration did not differ significantly by disease severity (p=.115). EC-specific molecule-1 is not involved in the pathogenesis of E-PE. However, some studies in the literature report that EC-specific molecule-1 concentrations increased during the diagnosis of PE. Therefore, well-designed studies with a large sample are needed in cases of E-PE.Impact StatementWhat is already known on this subject? There is an increased risk of cardiovascular disease (CVD) in early-onset preeclampsia (E-PE) which is linked with endothelial dysfunction. Endothelial cell (EC)-specific molecule-1 stands out as an important marker in EC dysfunction related conditions such as preeclampsia.What the results of this study add? This study showed that EC-specific molecule-1 is not associated with the CVDs risk linked with endothelial dysfunction in E-PE. Additionally, there was also no significant relationship was detected between the severity of E-PE and EC-specific molecule-1 concentrations.What the implications are of these findings for clinical practice and/or further research? Endothelial cell-specific molecule-1 is not involved in the pathogenesis of E-PE. Moreover, advantageous and easy-to-measure markers are needed in larger sample studies to better understand the aetiology of E-PE.

Markers of Endothelial Injury and Dysfunction in Early- and Late-Onset Preeclampsia

With regard to differences in the clinical symptoms of preeclampsia (PE), the degree of endothelial dysfunction may differ between early and late-onset preeclampsia (EOP and LOP). The authors of this study examined it by assessing the endothelial injury level in women with EOP (20 patients) and LOP (20 patients) and in normotensive pregnant women (20 patients) in their late second and third trimesters of pregnancy, using the two markers-the serum concentration of hyaluronan (HA) and the serum level of soluble vascular cell adhesion molecule-1 (sVCAM-1). The serum concentrations of HA and sVCAM-1 did not differ significantly between the EOP and LOP patients. However, these were statistically higher than that of the control group participants (p < 0.05; p < 0.001). A significant correlation between the levels of HA and sVCAM-1 was found both in the entire group of patients with preeclampsia (p = 0.0277) and in women with late-onset disease (p = 0.0364), but not in the patients with early-onset preeclampsia (p = 0.331). The obtained results indicated a comparable level of endothelial injury in the two types of PE. The presence of a similar degree of endothelial injury in patients with EOP and LOP should create awareness among all clinicians about the possible fatal complications in both groups of patients with PE.

Can Endothelial Glycocalyx Be a Major Morphological Substrate in Pre-Eclampsia?

Today pre-eclampsia (PE) is considered as a disease of various theories; still all of them agree that endothelial dysfunction is the leading pathogenic factor. Endothelial dysfunction is a sequence of permanent immune activation, resulting in the change of both the phenotype and the functions of an endothelial cell and of the extracellular layer associated with the cell membrane—endothelial glycocalyx (eGC). Numerous studies demonstrate that eGC mediates and regulates the key functions of endothelial cells including regulation of vascular tone and thromboresistance; and these functions are disrupted during PE. Taking into account that eGC and its components undergo alterations under pathological conditions leading to endothelial activation, it is supposed that eGC plays a certain role in pathogenesis of PE. Envisaging the eGC damage as a key factor of PE, might be a new approach to prevention, treatment, and rehabilitation of patients with PE. This approach could include the development of drugs protecting eGC and promoting regeneration of this structure. Since the issue of PE is far from being solved, any effort in this direction might be valuable.

Maternal plasma endocan levels in intrauterine growth restriction

Objectives: Intrauterine growth restriction (IUGR) is diagnosed when the estimated fetal weight remains below the 10th percentile of gestational age based on pathological restriction of growth and/or accompanying Doppler abnormalities. Endothelial dysfunction is a common pathogenetic pathway underlying IUGR etiology. Endocan (ESM-1) is a novel marker of endothelial dysfunction and inflammation found in the maternal circulation. This study was designed to compare plasma endocan levels between pregnancies complicated with IUGR and a control group.Study design: Forty-four pregnancies complicated with IUGR and 47 healthy pregnancies were included. Maternal plasma endocan levels were detected by ELISA. Parametric data was studied by Student's t-test. Mann-Whitney U-test was used in analyzing non-parametric data. Categorical variables underwent chi-square test. ROC analysis was performed to define the cutoff value of endocan in detecting IUGR. Spearman correlation test was performed.Results: Maternal plasma endocan level varied significantly between IUGR and healthy pregnancies and was 1.8 fold higher in the IUGR group (793.0 (IQR:544.4-1896.0) ng/L vs. 441.8 (IQR: 408.3-512.4) ng/L, p < .001). There was a weak negative correlation between endocan level and 5th and 10th minute APGAR Scores (r =  -0.256; p = .015 and r =  -0.215; p = .042, respectively), a weak positive correlation with umbilical artery pulsatility index, and a moderate negative correlation with cerebroplacental ratio (r  =  0.394; p < .001 and r =  -0.459; p < .001, respectively).Conclusions: There was a significant difference between endocan levels of IUGR and healthy pregnancies. Further studies might be designed to investigate the performance of endocan in predicting neonatal outcomes for pregnancies complicated with IUGR.

Circulating endocan and preeclampsia: a meta-analysis

Background: Endocan, a novel protein involved in inflammation and endothelial dysfunction, has been suggested to be related to preeclampsia, although the results of previous studies were not consistent. The aim of the study was to evaluate the potential difference of circulating endocan in women with preeclampsia and those with normal pregnancy.

Methods: Matched case–control studies evaluating the difference of circulating endocan between women with preeclampsia and those with normal pregnancy were identified via systematic search of PubMed and Embase databases. A random-effect model or a fixed-effect model was used to pool the results according to the heterogeneity. Subgroup analysis was performed to evaluate whether the timing of preeclampsia onset affected the outcome.

Results: Overall, eight matched case–control studies, including 451 women with preeclampsia and 442 women with normal pregnancy were included. Significant heterogeneity was detected among the included studies (P for Cochrane’s Q test = 0.006, I² = 65%). Meta-analysis with a random-effect model showed that women with preeclampsia had significantly higher circulating level of endocan compared with women with normal pregnancy (standardized mean difference = 0.37, 95% confidence interval: 0.13–0.62, P = 0.003). Subsequent subgroup analyses showed that the difference of circulating endocan between women with early onset preeclampsia and those with normal pregnancy was not statistically different from that between women with late-onset preeclampsia and those with normal pregnancy (P for subgroup difference = 0.81).

Conclusions: Women with preeclampsia have higher circulating endocan than those with normal pregnancy.

Serum endocan concentration and its correlation with severity of hypertensive disorders in pregnancy

Introduction: Endocan plays a role in the development of vascular tissue in health and disease and is an indicator of endothelial cells activation and angiogenesis.Objective: The aim of this study was to investigate the relationship between endocan serum levels and various types of hypertensive disorders in pregnant women.Patients and methods: We created three study groups (preeclampsia [n = 60], chronic hypertension [n = 39], gestational hypertension [n = 58]) and the control group consisting of 59 healthy pregnant women. The endocan serum concentration was assessed using commercially available ELISA kit.Results: There were no statistically significant differences in endocan serum levels (pg/mL) in each study group compared to controls. The multiple regression did not reveal significant differences between endocan levels in each study group after adjustment for prepregnancy BMI. We did not find any significant correlations between the endocan serum level and patients' age, gestational age (GA) at sample collection, prepregnancy BMI, systolic blood pressure, diastolic blood pressure, and 24-hour urinary protein excretion in each analyzed group. Moreover, in the preeclamptic participants, we did not observe a significant relationship between the endocan concentration and the features indicating the severity of the disease other than elevated blood pressure. There were no differences in endocan serum level in preeclampsia subgroups: early-onset versus late-onset and mild versus severe preeclampsia.Conclusions: Endocan is not involved in the pathogenesis of hypertensive disorders in pregnant women and could not be regarded as a marker of endothelial dysfunction in these cases.

Mechanisms of Endothelial Dysfunction in Hypertensive Pregnancy and Preeclampsia

Preeclampsia is a pregnancy-related disorder characterized by hypertension and could lead to maternal and fetal morbidity and mortality. Although the causative factors and pathophysiological mechanisms are unclear, endothelial dysfunction is a major hallmark of preeclampsia. Clinical tests and experimental research have suggested that generalized endotheliosis in the systemic, renal, cerebral, and hepatic circulation could decrease endothelium-derived vasodilators such as nitric oxide, prostacyclin, and hyperpolarization factor and increase vasoconstrictors such as endothelin-1 and thromboxane A2, leading to increased vasoconstriction, hypertension, and other manifestation of preeclampsia. In search for the upstream mechanisms that could cause endothelial dysfunction, certain genetic, demographic, and environmental risk factors have been suggested to cause abnormal expression of uteroplacental integrins, cytokines, and matrix metalloproteinases, leading to decreased maternal tolerance, apoptosis of invasive trophoblast cells, inadequate spiral arteries remodeling, reduced uterine perfusion pressure (RUPP), and placental ischemia/hypoxia. RUPP may cause imbalance between the antiangiogenic factors soluble fms-like tyrosine kinase-1 and soluble endoglin and the proangiogenic factors vascular endothelial growth factor and placental growth factor, or stimulate the release of other circulating bioactive factors such as inflammatory cytokines, hypoxia-inducible factor-1, reactive oxygen species, and angiotensin AT1 receptor agonistic autoantibodies. These circulating factors could then target endothelial cells and cause generalized endothelial dysfunction. Therapeutic options are currently limited, but understanding the factors involved in endothelial dysfunction could help design new approaches for prediction and management of preeclampsia.

A Dormant Microbial Component in the Development of Preeclampsia

Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.