Complex estimation of mitochondrial changes of immunocompetent blood cells in pregnant women with urgent and premature birth

Abstract

Inflammation is among the factors promoting development of premature rupture of the membranes (PPROM). Upon the conditions of physiological immune imbalance in pregnancy, inflammation modifies its course and can even change the immune response. Appropriate indexes may be quantitative and functional. We used a marker of mitochondrial membrane potential (MPM, Ay) as an integral index of the functional state of immunocompetent blood cells (IBC) in 159 women who were examined at 8-14 weeks of gestation; they were observed up to 34-36 weeks. Of these cohort, 121 women were referred to a comparison group. The main group (n = 46) consisted of pregnant women with PPROM at the term of 28-33 weeks. The examination was carried out according to current medical standards, with informed consent, being approved by the Ethics committee at the Khabarovsk branch of Far Eastern Scientific Centre of Physiology and Pathology of Respiration — Research Institute of Maternity and Childhood Protection. Additionally, MPM and lymphocyte populations were determined by flow cytometry. The degree of disturbed energy supply in the IBC was based on the data of simultaneous determination of lymphocyte, granulocyte and monocyte numbers with reduced MPM values (application for invention No. 2020115963), thus revealing 3 degrees of energy deficiency: 1st degree, monovariant IBC composition with reduced MPM; 2nd degree, bivariant composition, 3rd degree, total changes. A relative and absolute decrease in CD3 (72% vs 78% and 1624 vs 1980), CD8 (28% vs 33% and 651 vs 851), an increase in CD19 (14% vs 9% and 304 vs 219) were revealed in pregnant women with PPROM. When assessing MPM values in the IBC populations, a decreased proportion of women without energy deficiency from the 1st to the 2nd trimester (from 41% to 30%), due to the 3rd degree of energy deficiency (from 17% to 26%) was detected. A shift of affected pools at the 2nd degree of energy deficiency in favor of lymphocytic-granulocytic association (from 7% to 25%) from lymphocytic-monocytic compartment (from 73% to 50%) was found. From the 2nd to 3rd trimester, we have detected redistribution of granulocyte pools at the 1st degree (0 to 8%) and from the lymphocytic-granulocytic association (25% and 5%) to monocytic-granulocytic (25% and 40%). In the group with PPROM, there was a decreased proportion of pregnant women without energy deficiency (13% and 27%), as well as with the 1st and 2nd degrees (17% vs 31% and 9% vs 17%), due to the 3rd degree of energy deficiency (61% and 26 %), relative to the comparison group. The IBC pools of in the main group were redistributed at the 1st degree in favor of granulocytes (25% and 8%), at the 2nd, in favor of the lymphocytic-monocytic association (100% and 55%) from the granulocytic-monocytic (0% and 40%). Such imbalance of bioenergetic processes in the IBC can be an important factor of pathologically ongoing inflammation. These changes could be caused by both higher incidence of infections in such patients and by alloimmune interactions between mother and fetus. However, they may also determine the pathological course of inflammation. Preterm birth, which is usually caused by PPROM, is a multifactorial pathological condition. However, independent on specific triggers, the changes in energy supply of IBC, at least, may serve as a significant biomarker of probability for this disorder.