Relation between circulating angiotensin II type 1 receptor agonistic autoantibodies and soluble fms-like tyrosine kinase 1 in the pathogenesis of preeclampsia

CONTEXT

Placental and circulatory soluble fms-like tyrosine kinase 1 (sFlt1) has proven to be elevated in pregnant women with preeclampsia, a disease characterized by hypertension, proteinuria, and endothelial dysfunction. Recent studies also demonstrated an autoantibody against the angiotensin II type 1 (AT1) receptor (AT1-AA) in that disease.

OBJECTIVE

Both factors are discussed as key players in the etiology of preeclampsia. However, it has not yet been clarified whether these two circulating factors correlate and whether synergy determines the severity of pathology.

DESIGN

AT1-AA was retrospectively determined by a bioassay and sFlt1 by an ELISA.

PATIENTS

Serum from second-trimester pregnancies with normal or abnormal uterine perfusion and in women at term with or without pregnancy pathology was analyzed.

RESULTS

Most of the preeclamptic patients were characterized by high sFlt1 levels and the presence of AT1-AA, although the agonistic effects of the antibody did not correlate with the sFlt1 concentrations (P = 0.85). Although AT1-AA was also detected in second-trimester pregnancies evidencing abnormal uterine perfusion without later pathology, sFlt1 was not significantly elevated in these pregnancies, compared with those with normal uterine perfusion. However, whereas women with abnormal perfusion and later pregnancy pathology did not differ in AT1-AA, compared with those with normal outcome, sFlt1 was significantly increased. Again, the two factors did not correlate (P = 0.15).

CONCLUSIONS

We conclude that AT1-AA bioactivity and sFlt1 concentrations do not correlate, are not mutually dependent, and are thus probably involved in distinct pathogenetic mechanisms. Both factors in combination may not be causative for the early impaired trophoblast invasion and pathological uterine perfusion.

Hidden Markov Models Based on Symbolic Dynamics for Statistical Modeling of Cardiovascular Control in Hypertensive Pregnancy Disorders

Discrete hidden Markov models (HMMs) were applied to classify pregnancy disorders. The observation sequence was generated by transforming RR and systolic blood pressure time series using symbolic dynamics. Time series were recorded from 15 women with pregnancy-induced hypertension, 34 with preeclampsia and 41 controls beyond 30th gestational week. HMMs with five to ten hidden states were found to be sufficient to characterize different blood pressure variability, whereas significant classification in RR-based HMMs was found using fifteen hidden states. Pregnancy disorders preeclampsia and pregnancy induced hypertension revealed different patho-physiological autonomous regulation supposing different etiology of both disorders.

Proteinuria in hypertensive pregnancy diseases is associated with a longer persistence of hypertension postpartum

As there is growing evidence that hypertensive pregnancy disorders are associated with a risk of cardiovascular diseases later, the resolution of hypertension postpartum (PP) is of high clinical significance. However, there is little knowledge about the factors that influence this normalization. The objectives of our study were (a) to investigate whether or not there are differences in the resolution of hypertension between the distinct types of hypertensive pregnancy disorders and (b) to analyse what clinical parameters may determine the resolution pattern PP. In this retrospective study, 52 patients with preeclampsia (PE), seven with HELLP syndrome (haemolysis, elevated liver enzymes, low platelets), 10 with chronic hypertension (CH) and 21 with pregnancy-induced hypertension (PIH) were recruited. The course of the clinical parameters until day 7 PP was documented. Patients with proteinuria (PE/HELLP) showed the highest blood pressure values PP, while patients with PIH and CH showed no blood pressure changes up to day 7 PP. In patients with proteinuric diseases, there was a significantly higher percentage of cases with persisting hypertension at day 3 PP (71% vs 48% PIH/CH group, P<0.05), and even at day 7 PP this percentage remained significantly higher (31% vs 19% PIH/CH group). Our study shows that patients with proteinuric pregnancy disorders have a delayed PP of hypertension. A high percentage of these women are discharged from hospital with persisting hypertension and proteinuria. These observations demand a more specific and long-term PP care for these women.

Baroreflex sensitivity, heart rate, and blood pressure variability in hypertensive pregnancy disorders

Hypertensive pregnancy disorders are a leading cause of perinatal and maternal morbidity and mortality. Heart rate variability (HRV), blood pressure variability (BPV), and baroreflex sensitivity (BRS) are relevant predictors of cardiovascular risk in humans. The aim of the study was to evaluate whether HRV, BPV, and BRS differ between distinct hypertensive pregnancy disorders. Continuous heart rate and blood pressure recordings were performed in 80 healthy pregnant women as controls (CON), 19 with chronic hypertension (CH), 18 with pregnancy-induced hypertension (PIH), and 44 with pre-eclampsia (PE). The data were assessed by time and frequency domain analysis, nonlinear dynamics, and BRS. BPV is markedly altered in all three groups with hypertensive disorders compared to healthy pregnancies, whereby changes were most pronounced in PE patients. Interestingly, this increase in PE patients did not lead to elevated spontaneous baroreflex events, while BPV changes in both the other hypertensive groups were paralleled by alterations in baroreflex parameters. The HRV is unaltered in CH and PE but significantly impaired in PIH. We conclude that parameters of the HRV, BPV, and BRS differ between various hypertensive pregnancy disorders. Thus, distinct clinical manifestations of hypertension in pregnancy have different pathophysiological, regulatory, and compensatory mechanisms.

[Abnormal uterine perfusion in the second trimester--current pathophysiological, diagnostic and therapeutic aspects]

Doppler sonographic measurement of uterine perfusion in second trimester pregnancies is nowadays an established, non-invasive method to assess uteroplacental blood supply and down-stream vascular resistance. This method is able to identify women at risk for subsequent pregnancy complications like preeclampsia and intrauterine growth retardation. However, its specificity is limited since not all pregnancies with pathological perfusion develop later complications. At present, there is no additional and independent marker available that could increase the predictive value of uterine Doppler sonography. Therapeutic approaches may improve clinical course and outcome of those high-risk pregnancies but do not target the cause of the disturbed placental development.

A study on transmission and a trial of chemoprophylaxis in contacts of leprosy patients: design, methodology and recruitment findings of COLEP

In this article, we describe the design, methodology and recruitment findings of the COLEP study. The objectives of this study were to determine the effectiveness of chemoprophylaxis with a single dose of rifampicin in the prevention of leprosy among close contacts of leprosy patients, and to find characteristics of contact groups most at risk to develop clinical leprosy. These characteristics should be usable by routine leprosy control programmes. COLEP consists of a cluster randomized, double-blind and placebo-controlled trial, a cohort study to determine risk factors characterizing the sub-groups most at risk within the total contact group of a patient, and a cohort study using a reference group from the general population to determine the prevalence and incidence of leprosy in the total population of the study area. The follow-up period will be 4 years. A coding system was developed describing the physical and genetic distance of the contact person to the patient. This study in Bangladesh includes 1037 newly diagnosed and previously untreated leprosy patients and their 21,867 contacts. The prevalence of leprosy among contacts was 7.3 per 1000. A total of 21,708 contacts without signs and symptoms of clinical leprosy are included in a trial of chemoprophylaxis with single dose rifampicin, and randomized at contact group level in treatment and placebo arms. The results of this large field trial will become available in the years to come.

Differences in platelet activation by prolactin and leptin

Hormones such as prolactin and leptin have recently been recognized as potent platelet aggregation co-activators, and have therefore been postulated as an additional risk factor for both arterial and venous thrombosis. Clinical situations exist that are known to be associated with higher leptin and/or prolactin levels (obesity, pregnancy, prolactinomas and anti-psychotic therapy respectively) and increased venous thrombosis or atherosclerosis risk. Therefore, we compared the impact of both hormones on platelet activation in vitro and in vivo. First, we investigated platelet aggregation and P-selectin expression after stimulation with 1,000 mU/l prolactin or 100 ng/ml leptin in five healthy volunteers in vitro. Prolactin revealed significant higher levels of P-selectin expression and platelet aggregation than leptin in all subjects. We also compared the correlation of prolactin and leptin values with the P-selection expression on platelets. Previously, we detected a significant correlation between prolactin values and ADP-stimulated P-selectin expression on platelets in pregnant women, patients with pituitary tumours, and patients on anti-psychotic therapy. In contrast, leptin did not correlate with P-selectin expression in all subject groups investigated. However, leptin correlated with body mass index in the subjects investigated. Our data indicate that prolactin has a stronger effect on platelet activation as leptin in vitro and in vivo. Moreover, our data suggest that the stronger effect of prolactin on ADP-stimulated platelet aggregation, compared to leptin, depends on higher stimulation of CD62p expression by prolactin.