Bradykinin promotes migration and invasion of human immortalized trophoblasts

Dexamethasone targets actin cytoskeleton signaling and inflammatory mediators to reverse sulfur mustard-induced toxicity in rabbit corneas

PURPOSE

Sulfur mustard (SM), a bi-functional alkylating agent, was used during World War I and the Iran-Iraq war. SM toxicity is ten times higher in eyes than in other tissues. Cornea is exceptionally susceptible to SM-injuries due to its anterior positioning and mucous-aqueous interphase. Ocular SM exposure induces blepharitis, photosensitivity, dry eye, epithelial defects, limbal ischemia and stem cell deficiency, and mustard gas keratopathy leading to temporary or permanent vision impairments. We demonstrated that dexamethasone (Dex) is a potent therapeutic intervention against SM-induced corneal injuries; however, its mechanism of action is not well known. Investigations employing proteomic profiling (LC-MS/MS) to understand molecular mechanisms behind SM-induced corneal injury and Dex efficacy were performed in the rabbit cornea exposed to SM and then received Dex treatment. PEAKS studio was used to extract, search, and summarize peptide identity. Ingenuity Pathway Analysis was used for pathway identification. Validation was performed using immunofluorescence. One-Way ANOVA (FDR < 0.05; p < 0.005) and Student's t-test (p < 0.05) were utilized for analyzing proteomics and IF data, respectively. Proteomic analysis revealed that SM-exposure upregulated tissue repair pathways, particularly actin cytoskeleton signaling and inflammation. Prominently dysregulated proteins included lipocalin2, coronin1A, actin-related protein2, actin-related protein2/3 complex subunit2, actin-related protein2/3 complex subunit4, cell division cycle42, ezrin, bradykinin/kininogen1, moesin, and profilin. Upregulated actin cytoskeleton signaling increases F-actin formation, dysregulating cell shape and motility. Dex reversed SM-induced increases in the aforementioned proteins levels to near control expression profiles. Dex aids corneal wound healing and improves corneal integrity via actin cytoskeletal signaling and anti-inflammatory effects following SM-induced injuries.

Kinin B1 receptor controls maternal adiponectin levels and influences offspring weight gain

Given the importance of the kinin B1 receptor in insulin and leptin hormonal regulation, which in turn is crucial in maternal adaptations to ensure nutrient supply to the fetus, we investigated the role of this receptor in maternal metabolism and fetoplacental development. Wild-type and kinin B1 receptor-deficient (B1KO) female mice were mated with male mice of the opposite genotype. Consequently, the entire litter was heterozygous for kinin B1 receptor, ensuring that there would be no influence of offspring genotype on the maternal phenotype. Maternal kinin B1 receptor blockade reduces adiponectin secretion by adipose tissue ex vivo, consistent with lower adiponectin levels in pregnant B1KO mice. Furthermore, fasting insulinemia also increased, which was associated with placental insulin resistance, reduced placental glycogen accumulation, and heavier offspring. Therefore, we propose the combination of chronic hyperinsulinemia and reduced adiponectin secretion in B1KO female mice create a maternal obesogenic environment that results in heavier pups.

The Influence of Nicotine on Trophoblast-Derived Exosomes in a Mouse Model of Pathogenic Preeclampsia

Preeclampsia (PE) is a serious complication of pregnancy with a pathogenesis that is not fully understood, though it involves the impaired invasion of extravillous trophoblasts (EVTs) into the decidual layer during implantation. Because the risk of PE is actually decreased by cigarette smoking, we considered the possibility that nicotine, a critical component of tobacco smoke, might protect against PE by modifying the content of exosomes from EVTs. We investigated the effects of nicotine on our PE model mouse and evaluated blood pressure. Next, exosomes were extracted from nicotine-treated extravillous trophoblasts (HTR-8/SVneo), and the peptide samples were evaluated by DIA (Data Independent Acquisition) proteomic analysis following nano LC-MS/MS. Hub proteins were identified using bioinformatic analysis. We found that nicotine significantly reduced blood pressure in a PE mouse model. Furthermore, we identified many proteins whose abundance in exosomes was modified by nicotine treatment of EVTs, and we used bioinformatic annotation and network analysis to select five key hub proteins with potential roles in the pathogenesis or prevention of PE. EVT-derived exosomes might influence the pathogenesis of PE because the cargo delivered by exosomes can signal to and modify the receiving cells and their environment.

MiR-29b-3p affects growth and biological functions of human extravillous trophoblast cells by regulating bradykinin B2 receptor

INTRODUCTION

This study investigated miR-29b-3p's effects and mechanisms in preeclampsia development.

MATERIAL AND METHODS

In this study, we analysed the pathology and expression of miR-29b-3p and B2R mRNA from normal and preeclampsia placenta tissues using hematoxylin and eosin staining and RT-qPCR assay. For cell experiments, we used transwell assay CCK-8, flow cytometry and wound healing assay to determine the effects and correlation of miR-29b-3p and B2R in HTR-8/SVneo cell proliferation, apoptosis, cell cycle, cell invasion and migration in a preeclampsia cell model. Moreover, the mechanisms were determined using Western blot or immunofluorescence in different groups.

RESULTS

Clinical analysis revealed that miR-29b-3p gene expression dramatically increased with increasing degree of preeclampsia (p < 0.001 or p < 0.05, respectively). The HTR-8/SVneo cell biological activities of the model group were significantly depressed (p < 0.001). However, with miR-29b-3p inhibitor or B2R transfection, the HTR-8/SVneo cell biological activities significantly recovered (p < 0.001). Western blot assay showed that B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 levels were suppressed in the model group, compared with those in the NC groups (p < 0.001, respectively). With miR-29b-3p inhibitor or B2R transfection, the protein expression levels of B2R, VEGF-A, CCND-1, MMP-2 and MMP-9 dramatically increased (p < 0.001, respectively).

CONCLUSIONS

The down-regulation of miR-29b-3p could improve HTR-8/SVneo cell biological activities in a preeclampsia cell model by targeting B2R.

Role of ACE2 in pregnancy and potential implications for COVID-19 susceptibility

In times of coronavirus disease 2019 (COVID-19), the impact of severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 infection on pregnancy is still unclear. The presence of angiotensin-converting enzyme (ACE) 2 (ACE2), the main receptor for SARS-CoV-2, in human placentas indicates that this organ can be vulnerable for viral infection during pregnancy. However, for this to happen, additional molecular processes are critical to allow viral entry in cells, its replication and disease manifestation, particularly in the placenta and/or feto-maternal circulation. Beyond the risk of vertical transmission, COVID-19 is also proposed to deplete ACE2 protein and its biological actions in the placenta. It is postulated that such effects may impair essential processes during placentation and maternal hemodynamic adaptations in COVID-19 pregnancy, features also observed in several disorders of pregnancy. This review gathers information indicating risks and protective features related to ACE2 changes in COVID-19 pregnancies. First, we describe the mechanisms of SARS-CoV-2 infection having ACE2 as a main entry door and current evidence of viral infection in the placenta. Further, we discuss the central role of ACE2 in physiological systems such as the renin-angiotensin system (RAS) and the kallikrein-kinin system (KKS), both active during placentation and hemodynamic adaptations of pregnancy. Significant knowledge gaps are also identified and should be urgently filled to better understand the fate of ACE2 in COVID-19 pregnancies and the potential associated risks. Emerging knowledge will be able to improve the early stratification of high-risk pregnancies with COVID-19 exposure as well as to guide better management and follow-up of these mothers and their children.

Cortisol Dose-Dependently Impairs Migration and Tube-like Formation in a Trophoblast Cell Line and Modulates Inflammatory and Angiogenic Genes

Several stimuli can change maternal hormone levels during pregnancy. These changes may affect trophoblastic cells and modulate the development of the embryo and the placental tissue itself. Changes in cortisol levels are associated with impaired trophoblast implantation and function, in addition to other pregnancy complications. This study aims to analyze the effects of low and high doses of cortisol on an extravillous trophoblast cell line, and the effects of various exposures to this hormone. SGHPL-4 cells were treated with cortisol at five doses (0–1000 nM) and two exposures (continuous: 24 h/day; and intermittent: 2 h/day). In intermittent treatment, cortisol acted mainly as an anti-inflammatory hormone, repressing gene expression of kinin B1 receptors, interleukin-6, and interleukin-1β. Continuous treatment modulated inflammatory and angiogenic pathways, significantly repressing angiogenic factors and their receptors. Cortisol affected cell migration and tube-like structures formation. In conclusion, both continuous and intermittent exposure to cortisol repressed the expression of inflammatory genes, while only continuous exposure repressed the expression of angiogenic genes, suggesting that a sustained increase in the levels of this hormone is more harmful than a high short-term increase. Cortisol also impaired tube-like structures formation, and kinin receptors may be involved in this response.

Bradykinin Exerts Independent Effects on Trophoblast Invasion and Blood Pressure in Pregnant Guinea Pigs

INTRODUCTION

The pleiotropic kininogen-kallikrein-kinin system is upregulated in pregnancy and localizes in the uteroplacental unit. To identify the systemic and local participation of the bradykinin type 2 receptor (B2R), this was antagonized by Bradyzide (BDZ) during 2 periods: from days 20 to 34 and from days 20 to 60 in pregnant guinea pigs.

METHODS

Pregnant guinea pigs received subcutaneous infusions of saline or BDZ from gestational day 20 until sacrifice on day 34 (Short B2R Antagonism [SH-B2RA]) or on day 60 (Prolonged B2R Antagonism [PR-B2RA]). In SH-BDZA, systolic blood pressure was determined on day 34, while in PR-BDZA it was measured preconceptionally, at days 40 and 60. On gestational day 60, plasma creatinine, uricemia, proteinuria, fetal, placental and maternal kidney weight, and the extent of trophoblast invasion were evaluated.

RESULTS

The SH-B2RA increased systolic blood pressure on day 34 and reduced trophoblast myometrial invasion, spiral artery remodeling, and placental sufficiency. The PR-B2RA suppressed the normal blood pressure fall observed on days 40 and 60; vascular transformation, placental efficiency, urinary protein, serum creatinine, and uric acid did not differ between the groups. The proportion of all studied mothers with lost fetuses was greater under BDZ infusion than in controls.

CONCLUSION

The increased systolic blood pressure and transient reduction in trophoblast invasion and fetal/placental weight in the SH-B2R blockade and the isolated impact on blood pressure in the PR-B2R blockade indicate that bradykinin independently modulates systemic hemodynamics and the uteroplacental unit through cognate vascular and local B2R receptors.

Asynchronous Embryo Transfer Followed by Comparative Transcriptomic Analysis of Conceptus Membranes and Endometrium Identifies Processes Important to the Establishment of Equine Pregnancy

Preimplantation horse conceptuses require nutrients and signals from histotroph, the composition of which is regulated by luteal progesterone and conceptus-secreted factors. To distinguish progesterone and conceptus effects we shortened the period of endometrial progesterone-priming by asynchronous embryo transfer. Day 8 embryos were transferred to synchronous (day 8) or asynchronous (day 3) recipients, and RNA sequencing was performed on endometrium and conceptuses recovered 6 and 11 days later (embryo days 14 and 19). Asynchrony resulted in many more differentially expressed genes (DEGs) in conceptus membranes (3473) than endometrium (715). Gene ontology analysis identified upregulation in biological processes related to organogenesis and preventing apoptosis in synchronous conceptuses on day 14, and in cell adhesion and migration on day 19. Asynchrony also resulted in large numbers of DEGs related to 'extracellular exosome'. In endometrium, genes involved in immunity, the inflammatory response, and apoptosis regulation were upregulated during synchronous pregnancy and, again, many genes related to extracellular exosome were differentially expressed. Interestingly, only 14 genes were differentially expressed in endometrium recovered 6 days after synchronous versus 11 days after asynchronous transfer (day 14 recipient in both). Among these, KNG1 and IGFBP3 were consistently upregulated in synchronous endometrium. Furthermore bradykinin, an active peptide cleaved from KNG1, stimulated prostaglandin release by cultured trophectoderm cells. The horse conceptus thus responds to a negatively asynchronous uterus by extensively adjusting its transcriptome, whereas the endometrial transcriptome is modified only subtly by a more advanced conceptus.

Immunomodulatory significance of natural peptides in mammalians: Promising agents for medical application

Modulation of immune responses by immunoregulatory agents, such as the natural or synthetic immunomodulatory peptides, has been suggested as a potential strategy to modulate immune system against infection and other immune-related diseases. These compositionally simple peptides have attracted much attention for many drug developers, due to their high activity, low toxicity and clear target specificity. Host defence peptides and milk-derived peptides are two kinds of natural immunomodulatory peptides which have been widely studied in mammalians. They could participate at the interface of innate and adaptive immunity by regulating immune effector cells. This review summarizes the recent advances in host defence peptides and milk-derived peptides as well as their general characteristics, immunomodulatory functions and possible applications.

Human Placental Vascular Reactivity in Health and Disease: Implications for the Treatment of Pre-eclampsia

Adequate development of the placenta is essential for optimal pregnancy outcome. Pre-eclampsia (PE) is increasingly recognized to be a consequence of placental dysfunction and can cause serious maternal and fetal complications during pregnancy. Furthermore, PE increases the risk of neonatal problems and has been shown to be a risk factor for cardiovascular disease of the mother later in life. Currently, there is no adequate treatment for PE, mainly because its multifactorial pathophysiology remains incompletely understood. It originates in early pregnancy with abnormal placentation and involves a cascade of dysregulated systems in the placental vasculature. To investigate therapeutic strategies it is essential to understand the regulation of vascular reactivity and remodeling of blood vessels in the placenta. Techniques using human tissue such as the ex vivo placental perfusion model provide insight in the vasoactive profile of the placenta, and are essential to study the effects of drugs on the fetal vasculature. This approach highlights the different pathways that are involved in the vascular regulation of the human placenta, changes that occur during PE and the importance of focusing on restoring these dysfunctional systems when studying treatment strategies for PE.

Bradykinin Exerts Independent Effects on Trophoblast Invasion and Blood Pressure in Pregnant Guinea Pigs

INTRODUCTION:

The pleiotropic kininogen-kallikrein-kinin system is upregulated in pregnancy and localizes in the uteroplacental unit. To identify the systemic and local participation of the bradykinin type 2 receptor (B2R), this was antagonized by Bradyzide (BDZ) during 2 periods: from days 20 to 34 and from days 20 to 60 in pregnant guinea pigs.

METHODS:

Pregnant guinea pigs received subcutaneous infusions of saline or BDZ from gestational day 20 until sacrifice on day 34 (Short B2R Antagonism [SH-B2RA]) or on day 60 (Prolonged B2R Antagonism [PR-B2RA]). In SH-BDZA, systolic blood pressure was determined on day 34, while in PR-BDZA it was measured preconceptionally, at days 40 and 60. On gestational day 60, plasma creatinine, uricemia, proteinuria, fetal, placental and maternal kidney weight, and the extent of trophoblast invasion were evaluated.

RESULTS:

The SH-B2RA increased systolic blood pressure on day 34 and reduced trophoblast myometrial invasion, spiral artery remodeling, and placental sufficiency. The PR-B2RA suppressed the normal blood pressure fall observed on days 40 and 60; vascular transformation, placental efficiency, urinary protein, serum creatinine, and uric acid did not differ between the groups. The proportion of all studied mothers with lost fetuses was greater under BDZ infusion than in controls.

CONCLUSION:

The increased systolic blood pressure and transient reduction in trophoblast invasion and fetal/placental weight in the SH-B2R blockade and the isolated impact on blood pressure in the PR-B2R blockade indicate that bradykinin independently modulates systemic hemodynamics and the uteroplacental unit through cognate vascular and local B2R receptors.

Bradykinin Sequestration by Plasmodium berghei Infected Erythrocytes Conditions B2R Signaling and Parasite Uptake by Fetal Trophoblasts

Plasmodium infection during pregnancy causes placental malfunction reducing fetus sustainability and leading to abortions, stillbirths, low birth weight or premature delivery. Accumulation of infected erythrocytes (IE) in the placenta is a key factor in placental malaria pathogenesis but the role played by fetal trophoblast that contact maternal blood has been neglected. Here we explore the hypothesis that interactions between Plasmodium-IE and fetal trophoblast cells impact on vasoactive alterations underlying placental dysfunction. We screened gene expression of key mediators in vasoactive pathways. We found that mRNA of bradykinin receptor 2 (B2R) and nitric oxide synthase (eNOS), as well as levels of bradykinin (BK), were decreased in late gestation placentas of pregnant Plasmodium berghei-infected mice. Co-culturing mouse trophoblasts with IE down-regulated B2R transcription and interleukin (IL)-6 secretion in a B2R-signaling dependent manner. IE showed increased levels of surface B2R and enhanced capacity to bind BK. We propose that down-regulation of B2R signaling in the course of IE–trophoblast interactions is due to BK sequestration by IE. In corroboration, levels of BK were lower in infected placentas and the positive correlation of B2R gene expression and fetal weight was disrupted by infection. This indicates that deregulation of the BK-B2R pathway is associated to placental dysfunction provoked by malaria infection. We further found that upon inhibition of B2R signaling, trophoblasts engulf IE to a lesser extent and show reduced production of IL-6. Our data suggest that BK sequestration by P. berghei represents a strategy for the parasite to ameliorate the risk of phagocytic capture by down modulating B2R activation.

Utero-placental cellular and nuclear expression of bradykinin B2 receptors in normal and preeclamptic pregnancies

The bradykinin type 2 receptor (B2R), main effector of the pleiotropic kallikrein-kinin system (KKS), has been localized in the key sites related to placentation in human, rat and guinea pig utero-placental units. The present study was directed to characterize the content, the cellular and subcellular localization of B2R in the villi and basal plate of placentas from normal and preeclamptic pregnancies by means of western blotting, immunohistochemistry and immunoelectron microscopy. The protein content of B2R was demonstrated in both placental zones. The villous placenta of normal and preeclamptic pregnancies expressed B2R in syncytiotrophoblast and fetal endothelium; the basal plate displayed B2R in extravillous trophoblasts and decidual cells. Lastly, immunogold electron microscopy revealed B2R in fetal endothelium, syncytiotrophoblast, extravillous cytotrophoblasts and decidual cells; in all cell types the receptor was mainly located in the cytosol and nucleus. The protein content of placental homogenates and the immunoreactivity in the different cells types did not differ between both study groups; however the abundance of nuclear immunogold B2R positive beads in extravillous trophoblasts was greater in the normal than in the preeclamptic placentas. The purpose of describing nuclear B2R in the utero-placental unit, and its increment in normal extravillous trophoblasts, is to stimulate the study of the functional pathways that may be relevant to understand the local role of the B2R in normal and preeclamptic gestation.

The extreme anterior domain is an essential craniofacial organizer acting through Kinin-Kallikrein signaling

The extreme anterior domain (EAD) is a conserved embryonic region that includes the presumptive mouth. We show that the Kinin-Kallikrein pathway is active in the EAD and necessary for craniofacial development in Xenopus and zebrafish. The mouth failed to form and neural crest (NC) development and migration was abnormal after loss of function (LOF) in the pathway genes kng, encoding Bradykinin (xBdk), carboxypeptidase-N (cpn), which cleaves Bradykinin, and neuronal nitric oxide synthase (nNOS). Consistent with a role for nitric oxide (NO) in face formation, endogenous NO levels declined after LOF in pathway genes, but these were restored and a normal face formed after medial implantation of xBdk-beads into LOF embryos. Facial transplants demonstrated that Cpn function from within the EAD is necessary for the migration of first arch cranial NC into the face and for promoting mouth opening. The study identifies the EAD as an essential craniofacial organizer acting through Kinin-Kallikrein signaling.

Administration of angiotensin II and a bradykinin B2 receptor blocker in midpregnancy impairs gestational outcome in guinea pigs

BACKGROUND

The opposing renin-angiotensin system (RAS) and kallikrein-kinin system (KKS) are upregulated in pregnancy and localize in the utero-placental unit. To test their participation as counter-regulators, circulating angiotensin II (AII) was exogenously elevated and the bradykinin B2 receptor (B2R) was antagonized in pregnant guinea-pigs. We hypothesized that disrupting the RAS/KKS balance during the period of maximal trophoblast invasion and placental development would provoke increased blood pressure, defective trophoblast invasion and a preeclampsia-like syndrome.

METHODS

Pregnant guinea-pigs received subcutaneous infusions of AII (200 μg/kg/day), the B2R antagonist Bradyzide (BDZ; 62.5 microg/kg/day), or both (AII + BDZ) from gestational day 20 to 34. Non-pregnant cycling animals were included in a control group (C NP) or received AII + BDZ (AII + BDZ NP) during 14 days. Systolic blood pressure was determined during cycle in C NP, and on the last day of infusion, and 6 and 26 days thereafter in the remaining groups. Twenty six days after the infusions blood and urine were extracted, fetuses, placentas and kidneys were weighed, and trophoblast invasion of spiral arteries was defined in the utero-placental units by immunocytochemistry.

RESULTS

Systolic blood pressure transiently rose in a subgroup of the pregnant females while receiving AII + BDZ infusion, but not in AII + BDZ NP. Plasma creatinine was higher in AII- and BDZ-treated dams, but no proteinuria or hyperuricemia were observed. Kidney weight increased in AII + BDZ-treated pregnant and non-pregnant females. Aborted and dead fetuses were increased in dams that received AII and AII + BDZ. The fetal/placental weight ratio was reduced in litters of AII + BDZ-treated mothers. All groups that received interventions during pregnancy showed reduced replacement of endothelial cells by extravillous trophoblasts in lateral and myometrial spiral arteries.

CONCLUSIONS

The acute effects on fetal viability, and the persistently impaired renal/placental sufficiency and incomplete arterial remodeling implicate the RAS and KKS in the adaptations in pregnancy. The results partially confirm our hypothesis, as a preeclampsia-like syndrome was not induced. We demonstrate the feasibility of characterizing systemic and local modifications in pregnant guinea-pig, supporting its use to study normal placentation and related disorders.

Atorvastatin-loaded hydrogel affects the smooth muscle cells of human veins

Intimal hyperplasia (IH) is the major cause of stenosis of vein grafts. Drugs such as statins prevent stenosis, but their systemic administration has limited effects. We developed a hyaluronic acid hydrogel matrix, which ensures a controlled release of atorvastatin (ATV) at the site of injury. The release kinetics demonstrated that 100% of ATV was released over 10 hours, independent of the loading concentration of the hydrogel. We investigated the effects of such a delivery on primary vascular smooth muscle cells isolated from human veins. ATV decreased the proliferation, migration, and passage of human smooth muscle cells (HSMCs) across a matrix barrier in a similar dose-dependent (5-10 µM) and time-dependent manner (24-72 hours), whether the drug was directly added to the culture medium or released from the hydrogel. Expression analysis of genes known to be involved in the development of IH demonstrated that the transcripts of both the gap junction protein connexin43 (Cx43) and plasminogen activator inhibitor-1 (PAI-1) were decreased after a 24-48-hour exposure to the hydrogel loaded with ATV, whereas the transcripts of the heme oxygenase (HO-1) and the inhibitor of tissue plasminogen activator were increased. At the protein level, Cx43, PAI-1, and metalloproteinase-9 expression were decreased, whereas HO-1 was upregulated in the presence of ATV. The data demonstrate that ATV released from a hydrogel has effects on HSMCs similar to the drug being freely dissolved in the environment.

Cellular characteristics of cultured canine trophoblasts

CONTENTS

Shallow trophoblast invasion is detrimental in human pregnancies, but represents normal endotheliochorial placentation in dogs. Factors regulating shallow trophoblast invasion into the canine decidua are not well described, but it is known that matrix metalloproteinases (MMPs) play a crucial role in trophoblast invasion in many species. Following the methods previously described for isolating human trophoblasts, canine trophoblasts were isolated using collagenase and trypsin digestions with Percoll density gradient centrifugation. In addition, placental pieces were cryopreserved prior to primary culture following methods previously described for human tissue. Expression of cytokeratin-7, MMP2 and MMP9 was confirmed using fluorescent immunocytochemistry. Cellular morphology was similar to that reported for trophoblasts. More than 97% of the cells cultured expressed cytokeratin-7. More cultured canine trophoblasts expressed MMP9 (54.7 ± 3.4%) compared with MMP2 (40.3 ± 1.8%) (p = 0.02). Although both MMPs were immunolocalized to the cytoplasm, MMP2 was found in large, coalescing granules, whereas MMP9 was more diffusely expressed throughout the cell. Cryogenic freezing of placental tissue prior to primary cell culture had no effect on cell proliferation (p = 0.37). This research has established a baseline for future studies investigating the canine placenta as a model for disorders of shallow trophoblast invasion in humans.

The kinin-kallikrein system: physiological roles, pathophysiology and its relationship to cancer biomarkers

The kinin-kallikrein system (KKS) is an endogenous multiprotein cascade, the activation of which leads to triggering of the intrinsic coagulation pathway and enzymatic hydrolysis of kininogens with the consequent release of bradykinin-related peptides. This system plays a crucial role in inflammation, vasodilation, smooth muscle contraction, cardioprotection, vascular permeability, blood pressure control, coagulation and pain. In this review, we will outline the physiology and pathophysiology of the KKS and also highlight the association of this system with carcinogenesis and cancer progression.

Challenges posed to the maternal circulation by pregnancy

In primates, adequate growth of the fetus depends on the development of the uteroplacental unit. On the fetal side, this is achieved by the creation of the vascular network of the placenta. On the maternal side, the transformation of the spiral arteries into saccular nonreactive vessels by the trophoblast provides high blood flow to the intervillous space. Apart from the changes in the uterine arteries, the mother expands her plasma volume – at the expense of stimulating the renin-angiotensin-aldosterone system – and her cardiac output. In the maintaining of normotension in the face of an increased cardiac output and plasma volume, the renin-angiotensin-aldosterone system requires an enhanced vasodilator synthesis. Finally, in the late stages of pregnancy, a normal endothelial function is required to provide an ample margin to the activation provoked by deportation of syncytiotrophoblast fragments/factors to the maternal circulation. These four adaptative processes require various interrelated vasodilator systems. Deficient adaptations cause isolated or proteinuric arterial hypertension, intrauterine growth restriction, preterm delivery, and stillbirths, among others. Moreover, a normal or a defective adaptation to pregnancy influences maternal cardiovascular health in later life, as evidenced by various studies, most of them epidemiological; thus, pregnancy is now considered a stress test to the maternal cardiovascular system. Because of this, women planning to become pregnant should be screened for clinical and biochemical cardiovascular risks. Inversely, women presenting with hypertension in pregnancy should be thoroughly studied to detect and correct cardiovascular risks. The incorporation of the predictive value of a hypertensive pregnancy should help reduce cardiovascular disease in women.