Relationship between insulin resistance and circulating endothelial cells in pre-eclampsia

Pathophysiology of Pre-Eclampsia-Two Theories of the Development of the Disease

Pre-eclampsia (PE) continues to be a leading cause of maternal and fetal mortality and morbidity. While substantial progress has been made in understanding the pathomechanisms of PE, the pathophysiology of the disease is still not fully understood. While the "two-stage model" of the development of PE is the most widely accepted theory, stating that the placenta is the main source of the disease, there are some other pathophysiological models of PE. Among these other theories, the one considering heart dysfunction as serving as the primary cause of PE seems to be gaining increasing prominence. In this review, we aim to elucidate these two divergent concepts concerning the development of PE. Despite some differences in their proposed pathomechanisms, both theories share vital pathophysiological elements in common. A central and critical component in both models is impaired placental perfusion, which appears to be a crucial phenomenon in PE. A comprehensive understanding of the different pathomechanisms involved in PE may be helpful in clinical practice, prompting a more individual approach to care of patients with PE.

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.

miR-483 is downregulated in pre-eclampsia via targeting insulin-like growth factor 1 (IGF1) and regulates the PI3K/Akt/mTOR pathway of endothelial progenitor cells

AIM

Pre-eclampsia is a serious pregnancy-specific disease with an incidence of 9.4%. MicroRNAs play a key role in regulating factors in pre-eclampsia, but related research is still limited. This study aims to reveal the role and potential mechanisms of miR-483 in pre-eclampsia.

METHODS

miR-483 was detected in venous blood, umbilical cord blood and placental tissue of pre-eclampsia patients by Real-time Quantitative polymerase chain reaction (qRT-PCR). Insulin-like growth factor (IGF1) and miR-483 were detected by qRT-PCR and western blot in endothelial progenitor cells isolated from fetal umbilical cord blood. miR-483 was overexpressed and inhibited to detect changes of IGF1 and PI3K/Akt/mTOR pathway in endothelial progenitor cells by qRT-PCR and western blot.

RESULTS

miR-483 was downregulated in venous blood, umbilical cord blood and placental tissue of pre-eclampsia patients. In endothelial progenitor cells, overexpression of miR-483 inhibited the expression of IGF1, and inhibition of miR-483 promoted the expression of IGF1. miR-483 regulates the expression of PI3K, Akt, and mTOR in endothelial progenitor cells.

CONCLUSION

miR-483 is downregulated in pre-eclampsia and regulates endothelial progenitor cells by targeting IGF1. miR-483 is a potential alternative for diagnosing and treating pre-eclampsia.

Study on the correlation between adipocyte fatty-acid binding protein, glucolipid metabolism, and pre-eclampsia

AIM

We aimed to explore the relation between the level of adipocyte fatty-acid binding protein (A-FABP) in the gestational period and related indices of glucolipid metabolism, and the possible mechanisms of occurrence and development of pre-eclampsia.

METHODS

Seventy-six pre-eclampsia patients were enrolled and divided into the mild pre-eclampsia (n = 42) and severe pre-eclampsia (n = 34) groups. Forty-eight healthy pregnant women were selected as a control group. The indices of all participants were examined, including serum A-FABP, fasting insulin (FINS), fasting blood glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL), and homeostatic model assessment insulin resistance (HOMA-IR) index was calculated. After the delivery of the placenta, the level of A-FABP in the placenta was detected by immunochemistry. Then, the correlation between serum A-FABP and indices of glucolipid metabolism and placental A-FABP were analyzed.

RESULTS

Serum A-FABP, FINS, TG, TC, HOMA-IR, and placental A-FABP were significantly higher in pre-eclampsia patients and the level of HDL was obviously lower than in the control group. Serum A-FABP was positively correlated with FINS, TG, TC, and HOMA-IR, and placental A-FABP was negatively correlated with HDL in pre-eclampsia patients. In the control group, serum A-FABP was positively correlated only with TG, and uncorrelated with the other indices (P > 0.05).

CONCLUSION

The level of A-FABP was correlated with insulin resistance and indices of glucolipid metabolism in pre-eclampsia patients. High-levels of A-FABP might increase insulin resistance by causing glucose and lipid metabolism disorders and ultimately inducing the occurrence and development of pre-eclampsia.

Microvascular function in pre-eclampsia is influenced by insulin resistance and an imbalance of angiogenic mediators

In preeclampsia, maternal microvascular function is disrupted and angiogenesis is dysfunctional. Insulin resistance that occurs in some pregnancies also pathologically affects microvascular function. We wished to examine the relationship of angiogenic mediators and insulin resistance on microvascular health in pregnancy. We performed a nested, case–control study of 16 women who developed preeclampsia with 17 normal pregnant controls. We hypothesized that the impaired microvascular blood flow in preeclamptic women associated with an increased ratio of the antiangiogenic factors; (s‐endoglin [sEng] and soluble fms‐like tyrosine kinase‐1 [sFlt‐1]) and proangiogenic molecule (placental growth factor [PlGF]) could be influenced by insulin resistance. Serum samples taken after 28 weeks of gestation were measured for the angiogenic factors, insulin, and glucose alongside the inflammatory marker; tumor necrosis factor‐α and endothelial activation, namely; soluble vascular cell adhesion molecule 1, intercellular adhesion molecule‐1, and e‐selectin. Maternal microvascular blood flow, measured by strain gauge plethysmography, correlated with ratios of pro‐ and antiangiogenic mediators independently of preeclampsia. Decreased microvascular function measured in preeclampsia strongly correlated with both the antiangiogenic factor (sFlt‐1 + sEng): PlGF ratio and high levels of insulin resistance, and combining insulin resistance with antiangiogenic factor ratios further strengthened this relationship. In pregnancy, microvascular blood flow is strongly associated with perturbations in pro‐ and antiangiogenic mediators. In preeclampsia, the relationship of maternal microvascular dysfunction with antiangiogenic mediators is strengthened when combined with insulin resistance.