Increased vascular and uteroplacental matrix metalloproteinase-1 and -7 levels and collagen type I deposition in hypertension in pregnancy: role of TNF-α

Heat exposure induced risks of preterm birth mediated by maternal hypertension

Heat exposure is associated with an increased risk of preterm birth (PTB), with previous work suggesting that maternal blood pressure may play a role in these associations. Here we conducted a cohort study of 197,080 singleton live births across 8 provinces in China from 2015 to 2018. The study first estimated the associations between heat exposure, maternal hypertension and clinical subtypes of PTB, and then quantified the role of maternal hypertension in heat and PTB using mediation analyses. We show that heat exposure (>85th, 90th and 95th percentiles of local temperature distributions) spanning from conception to the 20th gestational week was associated with a 15-21% increase in PTB, and a 20-22% increase in medically indicated PTB. Heat exposure is likely to increase the risk of maternal hypertension and elevated blood pressure. Maternal hypertension mediated 15.7% and 33.9% of the effects of heat exposure (>90th percentile) on PTB and medically indicated PTB, respectively. Based on this large-population study, we found that exposure to heat in early pregnancy can increase the risk of maternal hypertension, thereby affecting the incidence of PTB.

Reduced uterine perfusion pressure as a model for preeclampsia and fetal growth restriction in murine: a systematic review and meta-analysis

The reduced uterine perfusion pressure (RUPP) model is frequently used to study preeclampsia and fetal growth restriction. An improved understanding of influential factors might improve reproducibility and reduce animal use considering the variability in RUPP phenotype. We performed a systematic review and meta-analysis by searching Medline and Embase (until 28 March, 2023) for RUPP studies in murine. Primary outcomes included maternal blood pressure (BP) or proteinuria, fetal weight or crown-rump length, fetal reabsorptions, or antiangiogenic factors. We aimed to identify influential factors by meta-regression analysis. We included 155 studies. Our meta-analysis showed that the RUPP procedure results in significantly higher BP (MD = 24.1 mmHg; [22.6; 25.7]; n = 148), proteinuria (SMD = 2.3; [0.9; 3.8]; n = 28), fetal reabsorptions (MD = 50.4%; [45.5; 55.2]; n = 42), circulating soluble FMS-like tyrosine kinase-1 (sFlt-1) (SMD = 2.6; [1.7; 3.4]; n = 34), and lower fetal weight (MD = -0.4 g; [-0.47; -0.34]; n = 113. The heterogeneity (variability between studies) in primary outcomes appeared ≥90%. Our meta-regression identified influential factors in the method and time point of BP measurement, randomization in fetal weight, and type of control group in sFlt-1. The RUPP is a robust model considering the evident differences in maternal and fetal outcomes. The high heterogeneity reflects the observed variability in phenotype. Because of underreporting, we observed reporting bias and a high risk of bias. We recommend standardizing study design by optimal time point and method chosen for readout measures to limit the variability. This contributes to improved reproducibility and thereby eventually improves the translational value of the RUPP model.

Increased Ca2+-dependent intrinsic tone and arterial stiffness in mesenteric microvessels of hypertensive pregnant rats

Preeclampsia is a pregnancy-related hypertensive disorder (HTN-Preg) with unclear mechanisms. We have shown increased vascular reactivity to extrinsic vasoconstrictors in HTN-Preg rats. Here, we test whether microvascular intrinsic tone and arterial stiffness could contribute to HTN-Preg, and examined the underlying cellular mechanisms. On gestational day 19, BP was recorded in normal pregnant (Preg) rats and Preg rats with reduced uterine perfusion pressure (RUPP), and mesenteric microvessels were mounted on a pressure myograph for measurement of intrinsic tone, simultaneous changes in [Ca2+]i (fura-2 340/380 ratio), and arterial stiffness. Arteries were incubated in Ca2+-containing and 0 Ca2+ (2 mM EGTA) Krebs, pressurized at 10 to 110 mmHg in 10 mmHg increments, and the % change in vessel diameter from initial diameter at 10 mmHg was analyzed for measurement of total (active + passive) intrinsic tone and passive intrinsic response, respectively. The passive response was then subtracted from the total intrinsic tone to determine the active myogenic tone. The strain-stress relationship was also constructed as a measure of arterial stiffness. BP was higher in RUPP vs Preg rats. In Ca2+-containing Krebs, increases in intraluminal pressure caused smaller increases in diameter and greater increases in [Ca2+]i in microvessels of RUPP vs Preg rats, suggesting increased Ca2+-dependent myogenic tone. In 0 Ca2+ Krebs, increases in pressure also caused less increases in diameter in microvessels of RUPP vs Preg rats, but with no changes in [Ca2+]i, suggesting changes in the structure and mechanics of the arterial wall. The total and passive strain-stress relationship was shifted to the left in microvessels of RUPP vs Preg rats, suggesting increased arterial wall stiffness. Histology and immunohistochemistry showed greater vascular wall thickness and collagen-I staining in RUPP vs Preg rats, supporting changes in the wall architecture and structural proteins. The increased active myogenic tone and underlying increases in Ca2+ signaling as well as the increased passive intrinsic response, arterial stiffness and collagen-I in the mesenteric microvessels could play a role in the regulation of blood flow to the splanchnic region and the increased vascular resistance and BP in HTN-Preg.

Mitochondria Targeted Antioxidant Significantly Alleviates Preeclampsia Caused by 11β-HSD2 Dysfunction via OPA1 and MtDNA Maintenance

We have previously demonstrated that placental 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) dysfunction contributes to PE pathogenesis. We sought to elucidate molecular mechanisms underlying 11β-HSD2 dysfunction-induced PE and to seek potential therapeutic targets using a 11β-HSD2 dysfunction-induced PE-like rat model as well as cultured extravillous trophoblasts (EVTs) since PE begins with impaired function of EVTs. In 11β-HSD2 dysfunction-induced PE-like rat model, we revealed that placental mitochondrial dysfunction occurred, which was associated with mitDNA instability and impaired mitochondrial dynamics, such as decreased optic atrophy 1 (OPA1) expression. MitoTEMPO treatment significantly alleviated the hallmark of PE-like features and improved mitDNA stability and mitochondrial dynamics in the placentas of rat PE-like model. In cultured human EVTs, we found that 11β-HSD2 dysfunction led to mitochondrial dysfunction and disrupted mtDNA stability. MitoTEMPO treatment improved impaired invasion and migration induced by 11β-HSD2 dysfunction in cultured EVTs. Further, we revealed that OPA1 was one of the key factors that mediated 11β-HSD2 dysfunction-induced excess ROS production, mitochondrial dysfunction and mtDNA reduction. Our data indicates that 11β-HSD2 dysfunction causes mitochondrial dysfunctions, which impairs trophoblast function and subsequently results in PE development. Our study immediately highlights that excess ROS is a potential therapeutic target for PE.

Cardiac extracellular matrix modulation in a rat-diabetic model: biochemical and anti-oxidant beneficial effect of pomegranate (Punica granatum) peel extract

CONTEXT

Disorders associated with diabetes and the beneficial effects of pomegranate peel extract (PPE) were widely reported. However effect of diabetes and PPE on extracellular matrix (ECM) remodelling needs further investigation.

OBJECTIVES

The focus of this study was to investigate the involvement of diabetes in cardiac ECM and the beneficial effects of PPE.

METHODS

Diabetes was induced by alloxan. PPE group was injected with 100 mg/kg of PPE. The phenolic profile of PPE was analyzed by HPLC. ECM was detected by ELISA. MMP-1, -8, -13 were determined by a colorimetric assay.

RESULTS

Compared to control fibronectin and laminin plasma content was higher respectively by 69% and 42% (p < 0.05) in diabetes. LV content of hydroxyproline and total collagen was higher by 195% (p < 0.01) and 56% (p < 0.05) in the diabetic group compared to control and restored at a similar level to controls in the PPE group. Compared to control, collagenase activity was significantly reduced by 32% (p < 0.05) and 35% (p < 0.05) respectively in ALX and PPF groups. There is no significant difference in collagenase activities in diabetic rats after and before PPE injection.

CONCLUSION

Diabetes is involved in cardiac ECM remodelling which can be improved by PPE. These findings will be useful for more understanding diabetes-induced cardiac disorders.

TNFα blockade reverses vascular and uteroplacental matrix metalloproteinases imbalance and collagen accumulation in hypertensive pregnant rats

Preeclampsia is a pregnancy-related disorder of maternal hypertension-in-pregnancy (HTN-Preg) and often fetal growth restriction (FGR). Placental ischemia could be an initiating event leading to inadequate vascular and uteroplacental remodeling and HTN-Preg; however, the molecular targets are unclear. To test the hypothesis that placental ischemia-induced release of proinflammatory cytokines target vascular and uteroplacental matrix metalloproteinases (MMPs), we tested if infusing TNFα (200 ng/kg/day) in day-14 pregnant (Preg) rats causes MMP imbalance and collagen accumulation, and if infusing TNFα decoy receptor Etanercept (0.4 mg/kg/day) in HTN-Preg rats with reduced uteroplacental perfusion pressure (RUPP) reverses MMP imbalance and collagen accumulation. On gestational day-19, blood pressure (BP) was higher in Preg + TNFα and RUPP vs Preg rats, and restored in RUPP + Etanercept rats. Gelatin zymography and Western blots revealed decreases in MMP-2 and MMP-9 and increases in MMP-1 and MMP-7 in aorta, uterus and placenta of Preg + TNFα and RUPP, that were reversed in RUPP + Etanercept rats. Collagen-I and IV were abundant in Preg + TNFα and RUPP, and were decreased in RUPP + Etanercept rats. The litter size, uterine, placenta, and pup weight were markedly reduced in RUPP, insignificantly reduced in Preg + TNFα, and slightly improved in RUPP + Etanercept rats. Thus TNFα blockade reverses the decreases in vascular and uteroplacental MMP-2 and MMP-9, and the increases in MMP-1, MMP-7 and accumulation of collagen-I and IV induced by placental ischemia and TNFα in HTN-Preg rats. Targeting TNFα using cytokine antagonists, or MMPs using MMP modulators could rectify MMP imbalance and collagen accumulation, restore vascular and uteroplacental remodeling, and improve BP in HTN-Preg and preeclampsia.

Inflammasomes in the Pathophysiology of Maternal Obesity: Potential Therapeutic Targets to Reduce Long-Term Adverse Health Outcomes in the Mother and Offspring

Over the past 20 years, the prevalence of obesity has risen dramatically worldwide, with an increase in occurrence among women in their reproductive age. Obesity during pregnancy is associated with significantly increased maternal and fetal morbidity and mortality. In addition to the short-term adverse health outcomes, both mother and the child are prone to develop cardiovascular, metabolic and neurological disorders. Although associations between obesity during pregnancy and adverse maternalfetal health outcomes are clear, the complex molecular mechanisms underlying maternal obesity remain largely unknown. This review describes multimeric self-assembling protein complexes, namely inflammasomes, as potential molecular targets in the pathophysiology of maternal obesity. Inflammasomes are implicated in both normal physiological and in pathophysiological processes that occur in response to an inflammatory milieu throughout gestation. This review highlights the current knowledge of inflammasome expression and its activity in pregnancies affected by maternal obesity. Key discussions in defining pharmacological inhibition of upstream as well as downstream targets of the inflammasome signaling cascade; and the inflammasome platform, as a potential therapeutic strategy in attenuating the pathophysiology underpinning inflammatory component in maternal obesity are presented herein.

Placental hypoxia: What have we learnt from small animal models?

Intrauterine hypoxia is a feature of pregnancy complications, both at high altitude and sea level. To understand the placental response to reduced oxygen availability, small animal models of maternal inhalation hypoxia (MIH) or reduced uterine perfusion pressure (RUPP) may be utilised. The aim of this review was to compare the findings of those studies to identify the role of oxygen availability in adapting placental structural and functional phenotypes in relation to fetal outcome. It also sought to explore the evidence for the involvement of particular genes and protein signalling pathways in the placenta in mediating hypoxia driven alterations. The data available demonstrate that both MIH and RUPP can induce placental hypoxia, which affects placental structure and vascularity, as well as glucose, amino acid, calcium and possibly lipid transport capacity. In addition, changes have been observed in HIF, VEGF, insulin/IGF2, AMPK, mTOR, PI3K and PPARγ signalling, which may be key in linking together observed phenotypes under conditions of placental hypoxia. Many different manipulations have been examined, with varied outcomes depending on the intensity, timing and duration of the insult. Some manipulations have detrimental effects on placental phenotype, viability and fetal growth, whereas in others, the placenta appears to adapt to uphold fetal growth despite the challenge of low oxygen. Together these data suggest a complex response of the placenta to reduced oxygen availability, which links to changes in fetal outcomes. However, further work is required to explore the role of fetal sex, altered maternal physiology and placental molecular mechanisms to fully understand placental responses to hypoxia and their relevance for pregnancy outcome.

Increased matrix metalloproteinases in cerebrospinal fluids of patients with major depressive disorder and schizophrenia

BACKGROUND

Chronic inflammation of the brain has a pivotal role in the pathophysiology of major depressive disorder (MDD) and schizophrenia (SCZ). Matrix metalloproteinases (MMPs) are extracellular proteases involved in pro-inflammatory processes and interact with IL-6, which is increased in the cerebrospinal fluid (CSF) of patients with MDD and SCZ. However, MMPs in the CSF in patients with MDD and SCZ remains unclear. Therefore, we compared MMPs in the CSF of patients with MDD and SCZ to those of healthy controls (HC).

METHODS

Japanese patients were diagnosed with DSM-IV-TR and clinical symptoms were assessed with the Hamilton Rating Scale for Depression for MDD and the Positive and Negative Syndrome Scale for SCZ. CSF was obtained from MDD (n=90), SCZ (n=86) and from age- and sex-matched HC (n=106). The levels of MMPs in CSF were measured with multiplex bead-based immunoassay.

RESULTS

The levels of MMP-2 in CSF were higher in both MDD and SCZ than HC and were positively correlated with clinical symptomatic scores in MDD, but not in SCZ. Regardless of diagnosis, the levels of MMP-2, -7 and -10 were positively correlated with each other, and the levels of MMP-7 and -10 were higher in MDD, but not in SCZ, compared to HC.

CONCLUSION

Increased CSF levels of MMP-2 in MDD and SCZ may be associated with brain inflammation. State-dependent alteration of MMP-2 and activation of cascades involving MMP-2, -7, and -10 appeared to have a role in the pathophysiology of MDD.

Collagen at the maternal-fetal interface in human pregnancy

The survival and development of a semi-allogenic fetus during pregnancy require special immune tolerance microenvironment at the maternal fetal interface. During the establishment of a successful pregnancy, the endometrium undergoes a series of changes, and the extracellular matrix (ECM) breaks down and remodels. Collagen is one of the most abundant ECM. Emerging evidence has shown that collagen and its fragment are expressed at the maternal fetal interface. The regulation of expression of collagen is quite complex, and this process involves a multitude of factors. Collagen exerts a critical role during the successful pregnancy. In addition, the abnormal expressions of collagen and its fragments are associated with certain pathological states associated with pregnancy, including recurrent miscarriage, diabetes mellitus with pregnancy, preeclampsia and so on. In this review, the expression and potential roles of collagen under conditions of physiological and pathological pregnancy are systematically discussed.

Inflammasomes-A Molecular Link for Altered Immunoregulation and Inflammation Mediated Vascular Dysfunction in Preeclampsia

Preeclampsia (PE) is a pregnancy-specific multisystem disorder and is associated with maladaptation of the maternal cardiovascular system and abnormal placentation. One of the important characteristics in the pathophysiology of PE is a dysfunction of the placenta. Placental insufficiency is associated with poor trophoblast uterine invasion and impaired transformation of the uterine spiral arterioles to high capacity and low impedance vessels and/or abnormalities in the development of chorionic villi. Significant progress in identifying potential molecular targets in the pathophysiology of PE is underway. The human placenta is immunologically functional with the trophoblast able to generate specific and diverse innate immune-like responses through their expression of multimeric self-assembling protein complexes, termed inflammasomes. However, the type of response is highly dependent upon the stimuli, the receptor(s) expressed and activated, the downstream signaling pathways involved, and the timing of gestation. Recent findings highlight that inflammasomes can act as a molecular link for several components at the syncytiotrophoblast surface and also in maternal blood thereby directly influencing each other. Thus, the inflammasome molecular platform can promote adverse inflammatory effects when chronically activated. This review highlights current knowledge in placental inflammasome expression and activity in PE-affected pregnancies, and consequently, vascular dysfunction in PE that must be addressed as an interdependent interactive process.

Estrogen-induced FOS-like 1 regulates matrix metalloproteinase expression and the motility of human endometrial and decidual stromal cells

The regulation mechanisms involved in matrix metalloproteinase (MMP) expression and the motility of human endometrial and decidual stromal cells (ESCs and DSCs, respectively) during decidualization remain unclear. DSCs show significant increased cell motility and expression of FOS-like 1 (FOSL1) and MMP1, MMP2, and MMP9 compared with ESCs, whereas lack of decidualization inducers leads to a rapid decrease in FOSL1 and MMP1 and MMP9 expression in DSCs in vitro Therefore, we hypothesized that a link exists between decidualization inducers and FOSL1 in up-regulation of motility during decidualization. Based on the response of ESCs/DSCs to different decidualization systems in vitro, we found that progesterone (P4) alone had no significant effect and that 17β-estradiol (E2) significantly increased cell motility and FOSL1 and MMP1 and MMP9 expression at the mRNA and protein levels, whereas 8-bromo-cAMP significantly decreased cell motility and FOSL1 and MMP9 expression in the presence of P4. In addition, we showed that E2 triggered phosphorylation of estrogen receptor 1 (ESR1), which could directly bind to the promoter of FOSL1 in ESCs/DSCs. Additionally, we also revealed silencing of ESR1 expression by siRNA abrogated E2-induced FOSL1 expression at the transcript and protein levels. Moreover, silencing of FOSL1 expression by siRNA was able to block E2-induced MMP1 and MMP9 expression and cell motility in ESCs/DSCs. Taken together, our data suggest that, in addition to its enhancement of secretory function, the change in MMP expression and cell motility is another component of the decidualization of ESCs/DSCs, including estrogen-dependent MMP1 and MMP9 expression mediated by E2-ESR1-FOSL1 signaling.

Decreased uterine vascularization and uterine arterial expansive remodeling with reduced matrix metalloproteinase-2 and -9 in hypertensive pregnancy

Normal pregnancy involves extensive remodeling of uterine and spiral arteries and matrix metalloproteinases (MMPs)-mediated proteolysis of extracellular matrix (ECM). Preeclampsia is characterized by hypertension in pregnancy (HTN-Preg) and intrauterine growth restriction (IUGR) with unclear mechanisms. Initial faulty placentation and reduced uterine perfusion pressure (RUPP) could release cytoactive factors and trigger an incessant cycle of suppressed trophoblast invasion of spiral arteries, further RUPP, and progressive placental ischemia leading to HTN-Preg and IUGR; however, the extent and depth of uterine vascularization and the proteolytic enzymes and ECM proteins involved are unclear. We hypothesized that HTN-Preg involves decreased uterine vascularization and arterial remodeling by MMPs and accumulation of ECM collagen. Blood pressure (BP) and fetal parameters were measured in normal Preg rats and RUPP rat model, and the uteri were assessed for vascularity, MMP levels, and collagen deposition. On gestational day 19, BP was higher, and the uterus weight, litter size, and pup weight were reduced in RUPP vs. Preg rats. Histology of uterine tissue sections showed reduced number (5.75 ± 0.95 vs. 11.50 ± 0.87) and size (0.05 ± 0.01 vs. 0.12 ± 0.02 mm2) of uterine spiral arterioles in RUPP vs. Preg rats. Immunohistochemistry showed localization of endothelial cell marker cluster of differentiation 31 (CD31) and smooth muscle marker α-actin in uterine arteriolar wall and confirmed decreased number/size of uterine arterioles in RUPP rats. The cytotrophoblast marker cytokeratin-7 showed less staining and invasion of spiral arteries in the deep decidua of RUPP vs. Preg rats. Uterine arteries showed less expansion in response to increases in intraluminal pressure in RUPP vs. Preg rats. Western blot analysis, gelatin zymography, and immunohistochemistry showed decreases in MMP-2 and MMP-9 and increases in the MMP substrate collagen-IV in uterus and uterine arteries of RUPP vs. those in Preg rats. The results suggest decreased number, size and expansiveness of spiral and uterine arteries with decreased MMP-2 and MMP-9 and increased collagen-IV in HTN-Preg. Decreased uterine vascularization and uterine arterial expansive remodeling by MMPs could be contributing mechanisms to uteroplacental ischemia in HTN-Preg and preeclampsia.NEW & NOTEWORTHY Preeclampsia is a pregnancy-related disorder in which initial inadequate placentation and RUPP cause the release of cytoactive factors and trigger a ceaseless cycle of suppressed trophoblast invasion of spiral arteries, further RUPP, and progressive placental ischemia leading to HTN-Preg and IUGR; however, the extent/depth of uterine vascularization and the driving proteolytic enzymes and ECM proteins are unclear. This study shows decreased number, size, and expansiveness of uterine spiral arteries, with decreased MMP-2 and MMP-9 and increased collagen-IV in HTN-Preg rats. The decreased uterine vascularization and uterine arterial expansive remodeling by MMPs could contribute to progressive uteroplacental ischemia in HTN-Preg and preeclampsia.

Role of B1 and B2 lymphocytes in placental ischemia-induced hypertension

Preeclampsia is a prevalent pregnancy complication characterized by new-onset maternal hypertension and inflammation, with placental ischemia as the initiating event. Studies of others have provided evidence for the importance of lymphocytes in placental ischemia-induced hypertension; however, the contributions of B1 versus B2 lymphocytes are unknown. We hypothesized that peritoneal B1 lymphocytes are important for placental ischemia-induced hypertension. As an initial test of this hypothesis, the effect of anti-CD20 depletion on both B-cell populations was determined in a reduced utero-placental perfusion pressure (RUPP) model of preeclampsia. Anti-murine CD20 monoclonal antibody (5 mg/kg, Clone 5D2) or corresponding mu IgG2a isotype control was administered intraperitoneally to timed pregnant Sprague-Dawley rats on gestation day (GD)10 and 13. RUPP or sham control surgeries were performed on GD14, and mean arterial pressure (MAP) was measured on GD19 from a carotid catheter. As anticipated, RUPP surgery increased MAP and heart rate and decreased mean fetal and placental weight. However, anti-CD20 treatment did not affect these responses. On GD19, B-cell populations were enumerated in the blood, peritoneal cavity, spleen, and placenta with flow cytometry. B1 and B2 cells were not significantly increased following RUPP. Anti-CD20 depleted B1 and B2 cells in peritoneum and circulation but depleted only B2 lymphocytes in spleen and placenta, with no effect on circulating or peritoneal IgM. Overall, these data do not exclude a role for antibodies produced by B cells before depletion but indicate the presence of B lymphocytes in the last trimester of pregnancy is not critical for placental ischemia-induced hypertension.NEW & NOTEWORTHY The adaptive and innate immune systems are implicated in hypertension, including the pregnancy-specific hypertensive condition preeclampsia. However, the mechanism of immune system dysfunction leading to pregnancy-induced hypertension is unresolved. In contrast to previous reports, this study reveals that the presence of classic B2 lymphocytes and peritoneal and circulating B1 lymphocytes is not required for development of hypertension following third trimester placental ischemia in a rat model of pregnancy-induced hypertension.

Disturbed Cardiorespiratory Adaptation in Preeclampsia: Return to Normal Stress Regulation Shortly after Delivery?

Women with pregnancies complicated by preeclampsia appear to be at increased risk of metabolic and vascular diseases in later life. Previous research has also indicated disturbed cardiorespiratory adaptation during pregnancy. The aim of this study was to follow up on the physiological stress response in preeclampsia several weeks postpartum. A standardized laboratory test was used to illustrate potential deviations in the physiological stress responding to mildly stressful events of the kind and intensity in which they regularly occur in further everyday life after pregnancy. Fifteen to seventeen weeks postpartum, 35 women previously affected by preeclampsia (19 mild, 16 severe preeclampsia), 38 women after uncomplicated pregnancies, and 51 age-matched healthy controls were exposed to a self-relevant stressor in a standardized stress-reactivity protocol. Reactivity of blood pressure, heart rate, stroke index, and systemic vascular resistance index as well as baroreceptor sensitivity were analyzed. In addition, the mutual adjustment of blood pressure, heart rate, and respiration, partitioned for influences of the sympathetic and the parasympathetic branches of the autonomic nervous system, were quantified by determining their phase synchronization. Findings indicated moderately elevated blood pressure levels in the nonpathological range, reduced stroke volume, and elevated systemic vascular resistance in women previously affected by preeclampsia. Despite these moderate abnormalities, at the time of testing, women with previous preeclampsia did not differ from the other groups in their physiological response patterns to acute stress. Furthermore, no differences between early, preterm, and term preeclampsia or mild and severe preeclampsia were observed at the time of testing. The findings suggest that the overall cardiovascular responses to moderate stressors return to normal in women who experience a pregnancy with preeclampsia a few weeks after delivery, while the operating point of the arterial baroreflex is readjusted to a higher pressure. Yet, their regulation mechanisms may remain different.

New Insights into the Process of Placentation and the Role of Oxidative Uterine Microenvironment

For a successful pregnancy to occur, a predecidualized receptive endometrium must be invaded by placental differentiated cells (extravillous trophoblast cells (EVTs)) and, at the same time, continue decidualization. EVT invasion is aimed at anchoring the placenta to the maternal uterus and ensuring local blood supply increase necessary to provide normal placental and foetal development. The first is achieved by migrating through the maternal endometrium and deeper into the myometrium, while the second by transforming uterine spiral arteries into large vessels. This process is a tightly regulated battle comprising interests of both the mother and the foetus. Invading EVTs are required to perform a scope of functions: move, adhere, proliferate, differentiate, interact, and digest the extracellular matrix (ECM); tolerate hypoxia; transform the maternal spiral arteries; and die by apoptosis. All these functions are modulated by their surrounding microenvironment: oxygen, soluble factors (e.g., cytokines, growth factors, and hormones), ECM proteins, and reactive oxygen species. A deeper comprehension of oxidative uterine microenvironment contribution to trophoblast function will be addressed in this review.

Statistical considerations in reporting cardiovascular research

The problem of inadequate statistical reporting is long standing and widespread in the biomedical literature, including in cardiovascular physiology. Although guidelines for reporting statistics have been available in clinical medicine for some time, there are currently no guidelines specific to cardiovascular physiology. To assess the need for guidelines, we determined the type and frequency of statistical tests and procedures currently used in the American Journal of Physiology-Heart and Circulatory Physiology. A PubMed search for articles published in the American Journal of Physiology-Heart and Circulatory Physiology between January 1, 2017, and October 6, 2017, provided a final sample of 146 articles evaluated for methods used and 38 articles for indepth analysis. The t-test and ANOVA accounted for 71% (212 of 300 articles) of the statistical tests performed. Of six categories of post hoc tests, Bonferroni and Tukey tests were used in 63% (62 of 98 articles). There was an overall lack in details provided by authors publishing in the American Journal of Physiology-Heart and Circulatory Physiology, and we compiled a list of recommended minimum reporting guidelines to aid authors in preparing manuscripts. Following these guidelines could substantially improve the quality of statistical reports and enhance data rigor and reproducibility.

Placental growth factor reverses decreased vascular and uteroplacental MMP-2 and MMP-9 and increased MMP-1 and MMP-7 and collagen types I and IV in hypertensive pregnancy

Preeclampsia is a complication of pregnancy manifested as maternal hypertension (HTN) and fetal intrauterine growth restriction, with unclear mechanisms. Placental ischemia increases antiangiogenic soluble fms-like tyrosine kinase-1 (sFlt-1) relative to angiogenic placental growth factor (PlGF); however, the molecular targets are unclear. To test the hypothesis that placental ischemia-induced changes in sFlt-1 and PlGF target vascular and uteroplacental matrix metalloproteinases (MMPs), we tested whether raising the sFlt-1-to-PlGF ratio by infusing sFlt-1 (10 µg·kg^-1·day^-1) in pregnant (Preg) rats increases blood pressure (BP) and alters MMPs and whether correcting sFlt-1/PlGF by infusing PlGF (20 µg·kg^-1·day^-1) in Preg rats with reduced uterine perfusion pressure (RUPP) improves BP and reverses the changes in MMPs. On gestational day 19, BP was higher and the litter size and uterine, placenta, and pup weight were less in Preg + sFlt-1 and RUPP than Preg rats and restored in RUPP + PlGF versus RUPP rats. Gelatin and casein zymography and Western blots revealed decreases in MMP-2 and MMP-9 and increases in MMP-1 and MMP-7 in the aorta, uterine artery, uterus, and placenta of Preg + sFlt-1 and RUPP versus Preg rats, which were reversed in RUPP + PlGF versus RUPP rats. Collagen types I and IV were more abundant in Preg + sFlt-1 and RUPP versus Preg rats and were reversed in RUPP + PlGF versus RUPP rats. Thus, PlGF reverses decreased vascular and uteroplacental MMP-2 and MMP-9 and increased MMP-1, MMP-7, and collagen types I and IV induced by placental ischemia and sFlt-1 in HTN in pregnancy. Angiogenic factors and MMP modulators could rectify changes in MMPs and collagen, restore vascular and uteroplacental remodeling, and improve HTN and intrauterine growth restriction in preeclampsia. NEW & NOTEWORTHY Understanding the mechanisms of preeclampsia could help in its prevention and management. This study shows that correcting soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) imbalance by infusing PlGF reverses the decreases in vascular and uteroplacental matrix metalloproteinase (MMP)-2 and MMP-9 and the increases in MMP-1, MMP-7, and collagen types I and IV induced by placental ischemia and antiangiogenic sFlt-1 in hypertension in pregnancy. Angiogenic factors and MMP modulators could rectify changes in vascular and uteroplacental MMPs and collagen content and ameliorate hypertension and intrauterine growth restriction in preeclampsia.

Guidelines for authors and reviewers on antibody use in physiology studies

Antibody use is a critical component of cardiovascular physiology research, and antibodies are used to monitor protein abundance (immunoblot analysis) and protein expression and localization (in tissue by immunohistochemistry and in cells by immunocytochemistry). With ongoing discussions on how to improve reproducibility and rigor, the goal of this review is to provide best practice guidelines regarding how to optimize antibody use for increased rigor and reproducibility in both immunoblot analysis and immunohistochemistry approaches.

Listen to this article’s corresponding podcast at http://ajpheart.podbean.com/e/guidelines-on-antibody-use-in-physiology-studies/.