A mitochondrial regulator protein, MNRR1, is elevated in the maternal blood of women with preeclampsia

OBJECTIVE

Preeclampsia, one of the most serious obstetric complications, is a heterogenous disorder resulting from different pathologic processes. However, placental oxidative stress and an anti-angiogenic state play a crucial role. Mitochondria are a major source of cellular reactive oxygen species. Abnormalities in mitochondrial structures, proteins, and functions have been observed in the placentae of patients with preeclampsia, thus mitochondrial dysfunction has been implicated in the mechanism of the disease. Mitochondrial nuclear retrograde regulator 1 (MNRR1) is a newly characterized bi-organellar protein with pleiotropic functions. In the mitochondria, this protein regulates cytochrome c oxidase activity and reactive oxygen species production, whereas in the nucleus, it regulates the transcription of a number of genes including response to tissue hypoxia and inflammatory signals. Since MNRR1 expression changes in response to hypoxia and to an inflammatory signal, MNRR1 could be a part of mitochondrial dysfunction and involved in the pathologic process of preeclampsia. This study aimed to determine whether the plasma MNRR1 concentration of women with preeclampsia differed from that of normal pregnant women.

METHODS

This retrospective case-control study included 97 women with preeclampsia, stratified by gestational age at delivery into early (<34 weeks, n = 40) and late (≥34 weeks, n = 57) preeclampsia and by the presence or absence of placental lesions consistent with maternal vascular malperfusion (MVM), the histologic counterpart of an anti-angiogenic state. Women with an uncomplicated pregnancy at various gestational ages who delivered at term served as controls (n = 80) and were further stratified into early (n = 25) and late (n = 55) controls according to gestational age at venipuncture. Maternal plasma MNRR1 concentrations were determined by an enzyme-linked immunosorbent assay.

RESULTS

1) Women with preeclampsia at the time of diagnosis (either early or late disease) had a significantly higher median (interquartile range, IQR) plasma MNRR1 concentration than the controls [early preeclampsia: 1632 (924-2926) pg/mL vs. 630 (448-4002) pg/mL, p = .026, and late preeclampsia: 1833 (1441-5534) pg/mL vs. 910 (526-6178) pg/mL, p = .021]. Among women with early preeclampsia, those with MVM lesions in the placenta had the highest median (IQR) plasma MNRR1 concentration among the three groups [with MVM: 2066 (1070-3188) pg/mL vs. without MVM: 888 (812-1781) pg/mL, p = .03; and with MVM vs. control: 630 (448-4002) pg/mL, p = .04]. There was no significant difference in the median plasma MNRR1 concentration between women with early preeclampsia without MVM lesions and those with an uncomplicated pregnancy (p = .3). By contrast, women with late preeclampsia, regardless of MVM lesions, had a significantly higher median (IQR) plasma MNRR1 concentration than women in the control group [with MVM: 1609 (1392-3135) pg/mL vs. control: 910 (526-6178), p = .045; and without MVM: 2023 (1578-8936) pg/mL vs. control, p = .01].

CONCLUSIONS

MNRR1, a mitochondrial regulator protein, is elevated in the maternal plasma of women with preeclampsia (both early and late) at the time of diagnosis. These findings may reflect some degree of mitochondrial dysfunction, intravascular inflammation, or other unknown pathologic processes that characterize this obstetrical syndrome.

[Nephrotic syndrome during pregnancy. Is it chronic glomerulonephritis or preeclampsia? Case report]

Nephrotic syndrome (NS) during pregnancy is a fairly rare pathology and its descriptions in the literature are few. For a long time, NS was associated only with an exacerbation of chronic glomerulonephritis or de novo nephritis, however, the experience of recent years has shown that NS can be a manifestation of the classical obstetric pathology - preeclampsia (PE). The appearance of massive proteinuria with the development of NS is most typical for early PE, which, of course, makes diagnosis difficult, especially if PE develops at an unusually early time (up to 20 weeks). To describe PE that does not fit into the classical criteria, the term "atypical" PE is now used, the development of which can be promoted by both obstetric and somatic risk factors. The presented clinical observation describes the development of early (within 14 weeks) severe PE with the NS at the onset of the disease in a patient with the first multiple pregnancy and complete hydatidiform mole (HM) of one of the fetuses. The progression of nephropathy with the addition of thrombotic microangiopathy and HELLP syndrome made it possible to assume the diagnosis of PE with a high probability. The rapid relief of all clinical manifestations after delivery confirmed this assumption. The role of HM as the main trigger of unusually early PE is discussed. Apparently, the patient's trophoblast disease in the form of hydatidiform mole caused the formation of a severe angiogenic imbalance already in the early stages of pregnancy, which led to the development of PE, which manifested NS as a consequence of podocytopathy due to VEGF deficiency. Thus, the development of NS in a pregnant patient without a history of kidney disease dictates, first of all, the exclusion of PE, until proven otherwise.

Peculiarities of the Expression of TLR4 and Inhibitor of TLR-Cascade Tollip in the Placenta in Earlyand Late-Onset Preeclampsia

We studied the peculiarities of the expression of TLR4 and its inhibitor Tollip in placentas obtained from women aged 23-40 years with early- and late-onset preeclampsia. Histological examination of placental tissue (hematoxylin and eosin staining) and immunohistochemical analysis with primary monoclonal antibodies to TLR4 and Tollip were performed on serial paraffin sections. It was found that the expression of TLR4 increased with increasing gestation term in both the syncytiotrophoblast and vascular endothelium of the placental villi (p<0.05). The expression of TLR4 in syncytiotrophoblast and in the endothelium in early preeclampsia was also significantly (p<0.00001) higher than in the reference group (preterm birth before 34 weeks gestation). In the vascular endothelium of placental villi, the expression of TLR4 in placentas from women with early-onset preeclampsia was higher than in late-onset preeclampsia (p=0.002), while Tollip was lower in early-onset preeclampsia than in the reference group. In preeclampsia, especially in early-onset preeclampsia, marked changes in the expression of TLR4 and Tollip in the placental tissue were detected; the severity of preeclampsia correlated with the degree of damage to the placental villi.

High normal blood pressure in early pregnancy also contribute to early onset preeclampsia and severe preeclampsia

OBJECTIVE

This study was to evaluate effects of high normal blood pressure (HNBP) in early pregnancy on total preeclampsia, early preeclampsia, and severe preeclampsia.

METHODS

We conducted a multicenter, national representative retrospective cohort study. HNBP was defined as systolic blood pressure between 130 and 140 mmHg or diastolic blood pressure between 85 and 90 mmHg. We used multivariable logistic regression to examine the associations of HNBP and the risks of above three types of preeclampsia.

RESULTS

We included 58 054 women who were normotensive and nulliparous in early pregnancy. 4 809 (8.3%) fulfilled the definition of having HNBP, 16 682 (28.7%) were in normal blood pressure group, and 36 563 (63.0%) were in optimal blood pressure group. The incidence rates of total preeclampsia, early preeclampsia, and severe preeclampsia were 2.1% (1 217), 0.8% (491), and 1.4% (814), respectively. Compared to having optimal blood pressure, women with HNBP had significantly higher odds of total preeclampsia (odds ratio (OR) = 4.028, 95% confidence interval (CI) 3.377, 4.804), severe preeclampsia (OR = 3.542, 95% CI 2.851, 4.400), and early preeclampsia (OR = 8.163, 95% CI 6.219, 10.715). Our restricted cubic spline results supported the dose-response relationship between continuous blood pressure and the odds ratio of three types of preeclampsia. The fraction of early preeclampsia associated with prehypertension was 58.6%, which was higher than those of total preeclampsia (42.2%) or severe preeclampsia (40.5%).

CONCLUSION

Women in early pregnancy with HNBP more likely develop total preeclampsia, early preeclampsia and severe preeclampsia, compared to those with optimal blood pressure. HNBP contribute more to early preeclampsia than severe preeclampsia. Our study provided robust epidemiological evidences for monitoring HNBP in early pregnancy to reduce the risks of preeclampsia.

Early-onset Preeclampsia in Lupus Pregnancy

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease that occurs during childbearing years and has been associated with preeclampsia. However, little is known about preeclampsia of early onset, which is associated with severe adverse maternal and perinatal outcomes.

METHODS

Using national population-based Swedish registers we identified women with SLE (≥2 visits with corresponding ICD codes) and a sample without SLE who gave birth to singleton infants 2001-12. Risk ratios (RR) and 95% confidence intervals (CI) for early-onset preeclampsia (defined by ICD codes corresponding to preeclampsia registered at <34 weeks) in SLE women were calculated based on adjusted modified Poisson models for first, subsequent, and all pregnancies.

RESULT

Among 742 births to women with SLE and 10 484 births to non-SLE women, there were 32 (4.3%) and 55 (0.5%) diagnoses of early-onset preeclampsia respectively. SLE was associated with an increased risk of early-onset preeclampsia (RR 7.8, 95% CI 4.8, 12.9, all pregnancies). The association remained similar upon restriction to women without pregestational hypertension. Adjustment for antiphospholipid syndrome (APS)-proxy attenuated the association. RRs for early-onset preeclampsia were smaller for subsequent pregnancies (RR 4.7, 95% CI 2.0, 11.2) compared to first and all (see above).

CONCLUSION

Women with SLE are at increased risk of early-onset preeclampsia and this increased risk may be independent of the traditional risk factors such as pregestational hypertension, APS, BMI, or smoking. Women with SLE during pregnancy should be closely monitored for early-onset preeclampsia and future research needs to identify the non-traditional preeclampsia factors that might cause this serious outcome.