Search

Background The flavonoid, luteolin, promotes vasorelaxation in various arteries through endothelial-dependent and independent mechanisms. Although there is growing interest in the vasoactive effects of flavonoids on maternal vascular function during pregnancy, it is unknown whether luteolin elicits vasorelaxation in the uterine circulation. We tested the hypothesis that luteolin induces vasorelaxation via endothelial-dependent mechanisms in uterine arteries from normal pregnant rats during late gestation. Methods Uterine arteries and aortas were isolated from Sprague-Dawley rats at gestational day 19 and prepared for wire myography. Results The potency of luteolin-induced vasorelaxation was examined between uterine arteries and the aortas. By 50 µM of luteolin, there was complete relaxation (100.5 ± 5.2%) in uterine arteries as compared to aortas (27.5 ± 10.0%). Even the highest concentration of 100 µM luteolin produced less than half relaxation (43.6 ± 8.6%) in aortas compared to uterine arteries. We then explored if luteolin-induced vasorelaxation in uterine arteries from pregnant rats was mediated by endothelial-dependent vasorelaxation pathways, including nitric oxide synthase (NOS), cyclooxygenase (COX), or potassium (K+) channels. Blocking these pathways with N(G)-Nitro- l -arginine methyl ester hydrochloride (L-NAME), indomethacin, or tetraethylammonium (TEA)/high potassium chloride (KCl), respectively, did not alter luteolin responses in uterine arteries from pregnant rats. These findings suggested that endothelial factors may not mediate luteolin-induced vasorelaxation in uterine arteries during pregnancy. Indeed, experiments where the endothelium was removed did not alter luteolin-induced vasorelaxation in uterine arteries during pregnancy. Conclusions Luteolin directly promotes vasorelaxation in the medial smooth muscle layer of uterine arteries during normal pregnancy.

Placental ischemia in preeclampsia (PE) results in hypertension and intrauterine growth restriction (IUGR). Stimulation of soluble guanylate cyclase (sGC) reduces blood pressure in the clinically relevant reduced uterine perfusion pressure (RUPP) rat model of PE, implicating involvement in RUPP-induced hypertension. However, the contribution of sGC in the development of IUGR in PE is not known. Thus, this study demonstrated the efficacy of Riociguat, an sGC stimulator, in IUGR reversion in the RUPP rat model of PE, and tested the hypothesis that improvement in fetal weight occurs in association with improvement in placental perfusion, placental morphology, and placental nutrient transport protein expression. Sham or RUPP surgery was performed at gestational day 14 (G14) with administration of vehicle (Sham or RUPP) or the sGC stimulator (Riociguat, 10 mg/kg/day sc; sGC-treated) until G20. Fetal weight was reduced ( P = 0.004) at G20 in RUPP but not in sGC-treated RUPP compared with Sham, the control group. At G20, uterine artery resistance index (UARI) was increased ( P = 0.010) in RUPP, indicating poor placental perfusion; proportional junctional zone surface area was elevated ( P = 0.035), indicating impaired placental development. These effects were ameliorated in sGC-treated RUPP. Placental protein expression of nutrient transporter heart fatty acid-binding protein (hFABP) was increased ( P = 0.008) in RUPP but not in sGC-treated RUPP, suggesting a compensatory mechanism to maintain normal neurodevelopment. Yet, UARI ( P < 0.001), proportional junctional zone surface area ( P = 0.013), and placental hFABP protein expression ( P = 0.008) were increased in sGC-treated Sham, suggesting a potential adverse effect of Riociguat. Collectively, these results suggest sGC contributes to IUGR in PE.

Preterm infants are at increased risk of death and disability, and cardiovascular instability after birth is a contributing factor. Immaturity of calcium handling in the preterm heart may limit myocardial contractility and cardiac output. Two transmembrane cation channels, TRPM6 and TRPM7, may regulate intracellular cardiac calcium in the neonatal period. The aim of this study was to determine

BACKGROUND. Preeclampsia (PE) is a disorder prevalent in 3–8% of pregnancies, characterized by hypertension, endothelial dysfunction and cardiac dysfunction, including hypertrophy and impaired global longitudinal strain (GLS), which indicates reduced contractility and tissue injury. Despite several clinical studies highlighting impaired cardiac function in these women, the underlying mechanisms have not been studied, in part, due to lack of an appropriate animal model. The Reduced Uterine Perfusion Pressure (RUPP) rat model produces a PE-like phenotype, including adverse cardiac remodeling. However, whether this translates to impaired cardiac function is not known. The aim of this study was to test the hypothesis that placental ischemia in the RUPP rat leads to impaired left ventricular (LV) systolic function and GLS. STUDY DESIGN. RUPP (n=10) rats underwent surgery to induce placental ischemia on gestational day (GD) 14. Sham (n=10) and RUPP rats had indwelling carotid catheters placed on GD 18, and blood pressure and echocardiography measurements were made on GD 19. RESULTS. The RUPP group exhibited increased mean arterial pressure compared to the Sham group (123±3 vs. 97±2 mmHg, P

Fetal growth restriction (FGR) is associated with increased risk for cardiovascular and renal disorders in later life. Prenatal sildenafil improves birth weight in FGR animal models. Whether sildenafil treatment protects against long-term cardiovascular and renal disease in these offspring is unknown. The aim of this study is to test the hypothesis that prenatal sildenafil ameliorates cardiovascular and renal function in FGR offspring of Dahl salt-sensitive rats. Sildenafil citrate (60 mg/kg per day) or control gel diet (containing 0.3% salt) was administered from gestational day ten until birth. In male and female offspring, the mean arterial pressure was measured by telemetry in 1 subset from week 5 until week twenty. Echocardiographic parameters, glomerular filtration rate, and fractional electrolyte excretion were determined in another subset at week 9. Aortic and mesenteric artery rings were prepared to assess endothelial-dependent (acetylcholine) and -independent (sodium nitroprusside) vasorelaxation (week 10). The rise in mean arterial pressure per week was attenuated in treated versus untreated male offspring. Mesenteric arteries showed an increased endothelium-dependent relaxation and improved endothelium-independent relaxation in treated versus control male offspring. No differences in aortic relaxation, echocardiographic parameters or renal function were observed between groups. Prenatal sildenafil treatment subtly improves cardiovascular but not renal function in the offspring of this FGR rat model. Translationally, in utero treatment could be beneficial for cardiovascular programming in a sex-specific manner; however, caution is warranted since recent human trials have been halted because of potentially deleterious neonatal side effects when treating pregnancies complicated with severe FGR with sildenafil.

Background Preeclampsia is a prominent risk factor for long‐term development of cardiovascular disease. Although existing studies report a strong correlation between preeclampsia and heart failure, the underlying mechanisms are poorly understood. One possibility is the glycoprotein growth factor activin A. During pregnancy, elevated activin A levels are associated with impaired cardiac global longitudinal strain at 1 year, but whether these changes persist beyond 1 year is not known. We hypothesized that activin A levels would remain increased more than 1 year after a preeclamptic pregnancy and correlate with impaired cardiac function. Methods and Results To test our hypothesis, we performed echocardiograms and measured activin A levels in women approximately 10 years after an uncomplicated pregnancy (n=25) or a pregnancy complicated by preeclampsia (n=21). Compared with women with a previously normal pregnancy, women with preeclampsia had worse global longitudinal strain (−18.3% versus −21.3%, P =0.001), left ventricular posterior wall thickness (0.91 mm versus 0.80 mm, P =0.003), and interventricular septal thickness (0.96 mm versus 0.81 mm, P =0.0002). Women with preeclampsia also had higher levels of activin A (0.52 versus 0.37 ng/mL, P =0.02) and activin/follistatin‐like 3 ratio (0.03 versus 0.02, P =0.04). In a multivariable model, the relationship between activin A levels and worsening global longitudinal strain persisted after adjusting for age at enrollment, mean arterial pressure, race, and body mass index ( P =0.003). Conclusions Our findings suggest that both activin A levels and global longitudinal strain are elevated 10 years after a pregnancy complicated by preeclampsia. Future studies are needed to better understand the relationship between preeclampsia, activin A, and long‐term cardiac function.

Preeclampsia (PE), a hypertensive disorder, occurs in 3% to 8% of pregnancies in the United States and affects over 200,000 women and newborns per year. The United States has seen a 25% increase in the incidence of PE, largely owing to increases in risk factors, including obesity and cardiovascular disease. Although the etiology of PE is not clear, it is believed that impaired spiral artery remodeling of the placenta reduces perfusion, leading to placental ischemia. Subsequently, the ischemic placenta releases antiangiogenic and pro-inflammatory factors, such as cytokines, reactive oxygen species, and the angiotensin II type 1 receptor autoantibody (AT1-AA), among others, into the maternal circulation. These factors cause widespread endothelial activation, upregulation of the endothelin system, and vasoconstriction. In turn, these changes affect the function of multiple organ systems including the kidneys, brain, liver, and heart. Despite extensive research into the pathophysiology of PE, the only treatment option remains early delivery of the baby and importantly, the placenta. While premature delivery is effective in ameliorating immediate risk to the mother, mounting evidence suggests that PE increases risk of cardiovascular disease later in life for both mother and baby. Notably, these women are at increased risk of hypertension, heart disease, and stroke, while offspring are at risk of obesity, hypertension, and neurological disease, among other complications, later in life. This article aims to discuss the current understanding of the diagnosis and pathophysiology of PE, as well as associated organ damage, maternal and fetal outcomes, and potential therapeutic avenues. © 2021 American Physiological Society. Compr Physiol 11:1315-1349, 2021.

Preeclampsia (PE) is a disorder prevalent in 3-8% of pregnancies, characterized by maternal hypertension, endothelial dysfunction and impaired cardiac function. PE develops in response to impaired spiral artery remodeling, leading to poor perfusion of the placenta. The ischemic placenta releases anti-angiogenic and pro-inflammatory factors into the maternal circulation leading to widespread endothelial activation. Studies have also shown that PE women exhibit decreased cardiac global longitudinal strain (GLS), a sensitive measure of systolic function that indicates fibrosis and tissue injury. Importantly, GLS remains impaired postpartum, when blood pressure has returned to normal, suggesting that placental factors could play a role in the development of cardiac dysfunction in PE. A recent study showed Activin A, a pro-fibrotic factor that is released by the placenta, is increased during PE and is predictive of impaired GLS one year postpartum. PE is a multifaceted disease, and whether increased circulating Activin A alone induces cardiac dysfunction is not known. We hypothesized that chronic excess levels of Activin A during pregnancy induces cardiac dysfunction. To address this, rats were administered vehicle ( n =6) or Activin A ( n =6/group; A2, 1.9μg/day, A3, 3 μg/day, A4, 6μg/day) via osmotic pump on gestational day (GD) 14. All animals had an indwelling carotid catheter placed on GD 18, followed by a comprehensive echocardiography assessment and blood pressure measurement on GD19. Activin A infusion resulted in significant increases in circulating Activin A in all treated groups (Vehicle, 585±47 pg/mL, A2, 2022±695 pg/mL, A3, 2511±409 pg/mL, A4, 2801±410 pg/mL, P

Animal models have been critical in investigating the pathogenesis, mediators, and even therapeutic options for a number of diseases, including preeclampsia. Preeclampsia is the leading cause of maternal and fetal morbidity and mortality worldwide. The placenta is thought to play a central role in the pathogenesis of this disease because it releases antiangiogenic and proinflammatory factors into the maternal circulation, resulting in the maternal syndrome. Despite the deleterious effects preeclampsia has been shown to have on the mother and baby during pregnancy and postpartum, there is still no effective treatment for this disease. Although clinical studies in patients are crucial to identify the involvement of pathogenic factors in preeclampsia, there are obvious limitations that prevent detailed investigation of the quantitative importance of time-dependent mechanisms involved in this syndrome. Animal models allow investigators to perform proof-of-concept studies and examine whether certain factors found in women with preeclampsia mediate hypertension and other manifestations of this disease. In this brief review, we summarize some of the more widely studied models used to investigate pathophysiological mechanisms that are thought to be involved in preeclampsia. These include models of placental ischemia, angiogenic imbalance, and maternal immune activation. Infusion of preeclampsia-related factors into animals has been widely studied to understand the specific mediators of this disease. These models have been included, in addition to a number of genetic models involved in overexpression of the renin-angiotensin system, complement activation, and trophoblast differentiation. Together, these models cover multiple mechanisms of preeclampsia from trophoblast dysfunction and impaired placental vascularization to the excess circulating placental factors and clinical manifestation of this disease. Most animal studies have been performed in rats and mice; however, we have also incorporated nonhuman primate models in this review. Preclinical animal models not only have been instrumental in understanding the pathophysiology of preeclampsia but also continue to be important tools in the search for novel therapeutic options for the treatment of this disease.

Background Approximately 60% of women have Stage B heart failure 1 year after a preeclamptic delivery. Emerging evidence suggests that the profibrotic growth factor activin A, which has been shown to induce cardiac fibrosis and hypertrophy, is elevated in preeclampsia and may be inhibited by aspirin therapy. We hypothesized that preeclamptic women receiving aspirin would have lower activin A levels and reduced global longitudinal strain ( GLS ), a sensitive measure of cardiac dysfunction, than women who do not receive aspirin. To test our hypothesis, we performed a cohort study of women with preeclampsia or superimposed preeclampsia and compared activin A levels and GLS in parturients who did or did not receive aspirin. Methods and Results Ninety‐two parturients were enrolled, of whom 25 (27%) received aspirin (81 mg/day) therapy. GLS , plasma activin A, and follistatin, which inactivates activin A, were measured. Women receiving aspirin therapy had lower median (interquartile range) levels of activin A (8.17 [3.70, 10.36] versus 12.77 [8.37, 31.25] ng/mL; P =0.001) and lower activin/follistatin ratio (0.59 [0.31, 0.93] versus 1.01 [0.64, 2.60] P =0.002) than women who did not receive aspirin, which also remained significant after multivariable analysis. Furthermore, GLS was worse in patients who did not receive aspirin (−19.84±2.50 versus −17.77±2.60%; P =0.03) despite no differences in blood pressure between groups. Conclusions Our study suggests that antepartum aspirin therapy reduced serum activin A levels and improved GLS in preeclamptic patients, suggesting that aspirin may mitigate the postpartum cardiac dysfunction seen in women with preeclampsia.

Preeclampsia is a pregnancy-specific disorder of maternal hypertension and reduced renal hemodynamics linked to reduced endothelial function. Placental ischemia is thought to be the culprit of this disease, as it causes the release of factors like tumor necrosis factor (TNF)-α that induce vascular endothelin-1 (ET-1) production. Interestingly, placental ischemia-induced hypertension in rats [reduced uterine perfusion pressure (RUPP) model] is abolished by ETA receptor blockade, suggesting a critical role for ET-1. Although it has been found that systemic induction of heme oxygenase (HO)-1 is associated with reduced ET-1 production and attenuated hypertension, it is unclear whether HO-1 directly modulates the increased ET-1 response to placental factors. We tested the hypothesis that HO-1 or its metabolites inhibit ET-1 production in human glomerular endothelial cells induced by serum of RUPP rats or TNF-α. Serum (5%) from RUPP hypertensive (mean arterial blood pressure 119 ± 9 mmHg) vs. normotensive pregnant (NP, 101 ± 6 mmHg, P < 0.001) rats increased ET-1 production (RUPP 168.8 ± 18.1 pg/ml, NP 80.3 ± 22.7 pg/ml, P < 0.001, n = 12/group). HO-1 induction [25 µM cobalt photoporphyrin (CoPP)] abolished RUPP serum-induced ET-1 production (1.6 ± 0.8 pg/ml, P < 0.001), whereas bilirubin (10 µM) significantly attenuated ET-1 release (125.3 ± 5.2 pg/ml, P = 0.005). Furthermore, TNF-α-induced ET-1 production (TNF-α 31.0 ± 8.4 vs. untreated 7.5 ± 0.4 pg/ml, P < 0.001) was reduced by CoPP (1.5 ± 0.8 pg/ml, P < 0.001) and bilirubin (10.5 ± 4.3 pg/ml, P < 0.001). These results suggest that circulating factors released during placental ischemia target the maternal glomerular endothelium to increase ET-1, and that pharmacological induction of HO-1 or bilirubin could be a treatment strategy to block this prohypertensive pathway in preeclampsia.

Aims: Bilirubin is associated with reduced risk of cardiovascular disease,as evidenced in conditions of mild hyperbilirubinaemia (Gilbert’s Syn-drome). Little is known regarding myocardial stress resistance in hyper-bilirubinaemic conditions or whether life-long exposure modifies cardiacfunction, which might contribute to protection from cardiovascular dis-ease.Methods: Hyperbilirubinaemic rats and littermate controls underwentechocardiography at 3, 6 and 12 months of age, with hearts subsequentlyassessed for resistance to 30 min of ischaemia. Hear t tissue was then col-lected for assessment of bilirubin content.Results: No difference in baseline cardiac function was evident until6 months onwards, where Gunn rats demonstrated aortic dilatation andreduced peak ejection velocities. Additionally, duration of ventricular ejec-tion increased progressively, indicating a negative inotropic effect of biliru-bin in v ivo. Ex vivo analysis of baseline function revealed reduced leftventricular pressure development (LVDP) and contractility in hyperbiliru-binaemic rats. Furthermore, stress resistance was improved in Gunn hearts:post-ischaemic recoveries of LVDP (76  22% vs. 29  17% Control,P < 0.01) and coronary flow (96  9% vs. 86  16% Control, P < 0.01)were improved in Gunn hearts, accompanied by reduced infarct area(21  5% vs. 47  15% Control, P < 0.01), and ventricular malondialde-hyde and protein carbonyl content. Expression of myocardial nitric oxide-regulating genes including Nos1 and Noa1 were not significantly different.Conclusions: These data reveal life-long hyperbilirubinaemia induces age-dependent hypocontractility in male Gunn rats, and improved stress resis-tance. In addition, bilirubi n exerts sex-independent effects on vascularstructure, myocardial function and ischaemic tolerance, the latter likelymediated via bilirubin’s antioxidant properties.Keywords bilirubin, cardiovascular disease, Gilbert’s syndrome, hemeoxygenase-1, ischaemia–reperfusion injury.

Preeclampsia (PE) is a leading cause of maternal and fetal mortality worldwide. Numerous studies indicate blood pressure is increased in individuals exposed to PE during fetal life. Currently, there are no effective therapeutics for PE. Our laboratory utilizes a rat model of PE induced by placental ischemia, the reduced uterine perfusion pressure (RUPP) model that results in intrauterine growth restriction (IUGR) and hypertension in the offspring. IUGR is dictated by inadequate uteroplacental blood flow and insufficient nutrient transport to the fetus. Preclinical use of a soluble guanylate cyclase (sGC) inducer abolishes hypertension in RUPP dams, but its effect on offspring is unknown. The purpose of this study was to test the hypothesis that maternal administration of a sGC inducer improves placental perfusion and nutrient transport, mitigating IUGR. RUPP or sham procedure was performed at day 14 of gestation and dams were administered vehicle or sGC inducer (riociguat, 10mg/kg/day, sc) from days 14 to 20 gestation. At day 20 of gestation uterine artery resistance index (UARI) was increased, indicative of poor perfusion, in vehicle-treated RUPP compared to vehicle-treated Sham (0.64±0.01 vs. 0.57±0.01 mm/s, respectively; p p p p p p

Preeclampsia (PE) is a disorder prevalent in 3-8% of pregnancies, characterized by maternal hypertension and endothelial dysfunction. More recently, it has been shown that preeclamptic women exhibit cardiac dysfunction, impaired global longitudinal strain (GLS), which is indicator of contractility and tissue injury, and increased circulating cardiac troponin I (cTnI), however the underlying mechanisms have not been well studied. The Reduced Uterine Perfusion Pressure (RUPP) model of placental ischemia mimics a PE-like phenotype, including hypertension, endothelial dysfunction and adverse cardiac remodeling. However, whether adverse remodeling translates to impaired cardiac function is not known. The aim of this study was to assess cardiac function in RUPP rats during pregnancy. We tested the hypothesis that placental ischemia in the RUPP rat leads to impaired left ventricular (LV) systolic function and GLS. To address this, all animals underwent comprehensive echocardiography assessment on gestational day (GD) 14. RUPP rats underwent surgery to place silver clips on the abdominal aorta and branches of the ovarian artery to induce placental ischemia. Both the Sham ( n =10) and RUPP ( n =10) rats had indwelling carotid catheters placed on GD 18, and blood pressure and echocardiography measurements were made on GD 19. The RUPP group showed significantly increased mean arterial pressure compared to the Sham group on GD 19 (123 ± 3 vs. 97 ± 2 mmHg, P

Preeclampsia (PE) is a pregnancy-specific disease characterized by placental ischemia, maternal endothelial dysfunction, and hypertension. The ischemic placenta releases anti-angiogenic factors, such as sFlt-1, which antagonizes the angiogenic factors, Placental Growth Factor (PlGF) and Vascular Endothelial Growth Factor (VEGF), causing endothelial dysfunction and impaired nitric oxide (NO) signaling. During normal pregnancy, NO would bind soluble guanylyl cyclase (sGC) increasing cGMP levels leading to vasodilation. However, in PE this signaling is reduced. sGC stimulators and activators are a novel class of drug that directly stimulate sGC despite low levels of NO. Our preliminary data suggest that sGC modulators reduce hypertension in an animal model of PE, but the mechanisms are not known. Therefore, this study tested the hypothesis that sGC stimulators (Riociguat) and activators (Cinaciguat) attenuate sFlt-1 production and increase PlGF levels in the placenta. Placentas were obtained from normal pregnant rats on gestational day 19. Isolated placental villi were plated (1 per well) and coated with Matrix Matrigel Basement Membrane. The villi were treated with various doses of sGC modulators (0.2μM, 1μM, 10μM, 30μM) and then exposed to a hypoxic environment (1% oxygen) for 48 hours. Levels of sFlt-1, PlGF, and VEGF were determined using an Enzyme-Linked Immunosorbent Assay kit.sFlt-1 concentration was significantly reduced in both groups treated with the stimulator or activator compared to the untreated group. The greatest attenuation was observed with the 30μM sGC activator treatment (Untreated, 5117±1313 pg/mL; 30μM sGC stimulator, 3975±621pg/mL, 30μM sGC activator, 3811±712 pg/mL, P

Preeclampsia (PE) is a pregnancy specific disorder associated with maternal hypertension and endothelial dysfunction caused by the release of anti-angiogenic and pro-inflammatory factors from the ischemic placenta. In addition, PE is associated with depletion of nitric oxide (NO), which, during normal pregnancy, binds to soluble guanylate cyclase (sGC), and synthesizes cGMP, to facilitate vasodilation. A recently developed drug, sGC activators have been shown to bind to the sGC molecule and increase activity independently of NO. However, whether these drugs might have therapeutic potential in PE is not known. We tested the hypothesis that sGC activators attenuates blood pressure in a placental ischemic rat by improving vascular function. Sprague-Dawley rats underwent Sham or RUPP (Reduced Uterine Perfusion Pressure) surgery on gestational day (GD) 14, where silver clips were placed on the abdominal aorta and branches of the ovarian artery to induce placental ischemia. Animals were then placed on placebo (P) or sGC activator (80 ppm, BAY 60-2770) -supplemented (sGC-A) diets, ad libitum, from GD14-19. To determine the effect of sGC activators on vascular function, uterine arteries were isolated from Sham and RUPP operated rats and mounted on a wire myograph. Vessels were pre-constricted and vasodilation was assessed by increasing doses of the sGC activator (Cinaciguat; Sigma, St Louis, MO). On GD19, RUPP surgery had significantly increased mean arterial blood pressure as expected (Sham+P, n =6, 100±6 mmHg; RUPP+P, n =6, 117±4 mmHg; Pn =6, 108±6 mmHg; P=0.02). Interestingly, in the presence of sGC activators (Cinaciguat), uterine arteries isolated from RUPP rats exhibited significantly improved vasodilation at doses of 1μM (Sham, n =5, 7±0.5 %; RUPP, n =3, 25±0.8 %; Pn =5, 7±0.5 %; RUPP, n =3, 28±1 %; P

Preeclampsia (PE) is a disorder of pregnancy typically characterized by new-onset hypertension and proteinuria after gestational week 20. Although preeclampsia is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disorder remain unclear and treatment options are limited. Placental ischemic events and the release of placental factors appear to play a critical role in the pathophysiology. These factors contribute to a generalized systemic vascular endothelial dysfunction and result in increased systemic vascular resistance and hypertension. There is increasing evidence to suggest that endothelin-1 (ET-1) in the maternal vascular endothelium is a critical final common pathway, whereby placental ischemic factors cause cardiovascular and renal dysfunction in the mother. Multiple studies report increased levels of ET-1 in PE. A number of experimental models of PE are also associated with elevated tissue levels of prepro-ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 excess, TNF-α excess, and AT1-AA infusion) have proven to be responsive to ET type A receptor antagonism. Recent studies also suggest that abnormalities in ET type B receptor signaling may also play a role in PE. Although numerous studies highlight the importance of the ET system in the pathogenesis of PE, further work is needed to determine whether ET receptor antagonists could provide an effective therapy for the management of this disease.

Bilirubin, a potentially toxic catabolite of heme and indicator of hepatobiliary insufficiency, exhibits potent cardiac and vascular protective properties. Individuals with Gilbert’s syndrome (GS) may experience hyperbilirubinemia in response to stressors including reduced hepatic bilirubin excretion/increased red blood cell breakdown, with individuals usually informed by their clinician that their condition is of little consequence. However, GS appears to protect from all-cause mortality, with progressively elevated total bilirubin associated with protection from ischemic heart and chronic obstructive pulmonary diseases. Bilirubin may protect against these diseases and associated mortality by reducing circulating cholesterol, oxidative lipid/protein modifications, and blood pressure. In addition, bilirubin inhibits platelet activation and protects the heart from ischemia-reperfusion injury. These effects attenuate multiple stages of the atherosclerotic process in addition to protecting the heart during resultant ischemic stress, likely underpinning the profound reduction in cardiovascular mortality in hyperbilirubinemic GS. This review outlines our current knowledge of and uses for bilirubin in clinical medicine and summarizes recent progress in revealing the physiological importance of this poorly understood molecule. We believe that this review will be of significant interest to clinicians, medical researchers, and individuals who have GS.

Preeclampsia (PE) is a disorder of pregnancy typically characterized by new onset hypertension after gestational week 20 and proteinuria. Although PE is one of the leading causes of maternal and perinatal morbidity and death worldwide, the mechanisms of the pathogenesis of the disease remain unclear and treatment options are limited. However, there is increasing evidence to suggest that endothelin-1 (ET-1) plays a critical role in the pathophysiology of PE. Multiple studies report that ET-1 is increased in PE and some studies report a positive correlation between ET-1 and the severity of symptoms. A number of experimental models of PE are also associated with elevated tissue levels of prepro ET-1 mRNA. Moreover, experimental models of PE (placental ischemia, sFlt-1 infusion, Tumor necrosis factor (TNF) -α infusion, and Angiotensin II type 1 receptor autoantibody (AT1-AA) infusion) have proven to be susceptible to Endothelin Type A (ETA) receptor antagonism. While the results are promising, further work is needed to determine whether ET antagonists could provide an effective therapy for the management of preeclampsia.

Mildly elevated circulating unconjugated bilirubin (UCB) is associated with protection against hypertension and ischemic heart disease. We assessed whether endogenously elevated bilirubin in Gunn rats modifies cardiovascular function and resistance to ischemic insult. Hearts were assessed ex vivo (Langendorff perfusion) and in vivo (Millar catheterization and echocardiography), and left ventricular myocardial gene expression was measured via quantitative real-time PCR. Ex vivo analysis revealed reduced intrinsic contractility in the Gunn myocardium (+dP/d t: 1,976 ± 622 vs. 2,907 ± 334 mmHg/s, P < 0.01; −dP/d t: −1,435 ± 372 vs. −2,234 ± 478 mmHg/s, P < 0.01), which correlated positively with myocardial UCB concentration ( P < 0.05). In vivo analyses showed no changes in left ventricular contractile parameters and ejection (fractional shortening and ejection fraction). However, Gunn rats exhibited reductions in the rate of aortic pressure development (3,008 ± 461 vs. 4,452 ± 644 mmHg/s, P < 0.02), mean aortic velocity (439 ± 64 vs. 644 ± 62 mm/s, P < 0.01), and aortic volume time integral pressure gradient (2.32 ± 0.65 vs. 5.72 ± 0.74 mmHg, P < 0.01), in association with significant aortic dilatation (12–24% increase in aortic diameter, P < 0.05). Ex vivo Gunn hearts exhibited improved ventricular function after 35 min of ischemia and 90 min of reperfusion (63 ± 14 vs. 35 ± 12%, P < 0.01). These effects were accompanied by increased glutathione peroxidase and reduced superoxide dismutase and phospholamban gene expression in Gunn rat myocardium ( P < 0.05). These data collectively indicate that hyperbilirubinemia in Gunn rats 1) reduces intrinsic cardiac contractility, which is compensated for in vivo; 2) induces aortic dilatation, which may beneficially influence aortic ejection velocities and pressures; and 3) may improve myocardial stress resistance in association with beneficial transcriptional changes. These effects may contribute to protection from cardiovascular disease with elevated bilirubin.

INTRODUCTION: Women with a history of preeclampsia (PE) have an increased risk to develop cardiovascular and renal diseases later in life, but the mechanisms underlying this effect are unknown. In rats, we assessed whether placental ischemia results in long-term effects on the maternal cardiovascular and renal systems using the Reduced Uterine Perfusion Pressure (RUPP) model for PE. METHODS: Sprague-Dawley rats received either a SHAM or RUPP operation at gestational day 14. The rats were followed for eight weeks after delivery (SHAM n=12, RUPP n=21) at which time mean arterial pressure (MAP; conscious), 24-hour albuminuria, GFR (transcutaneous, FITC-sinistrin), and cardiac function (Vevo 770 system) were assessed. Subsequently, all rats were sacrificed for mesenteric artery vasorelaxation and histology of heart and kidney. RESULTS: At eight weeks after delivery, there was no difference in MAP and albuminuria. However, RUPP rats showed a significantly reduced GFR [2.61 ± 0.53 vs 3.37 ± 0.74ml/min; p=0.01]. Ultrasound showed comparable cardiac structure, but RUPP rats had a lower left ventricular ejection fraction (62 ± 7 vs 69 ± 10%; p=0.04). Heart and kidney histology was not different between SHAM or RUPP rats. Furthermore, there were no differences in endothelial dependent or independent vasorelaxation. CONCLUSIONS: We show that exposure to placental ischemia in rats is accompanied by functional disturbances in maternal renal and cardiac function eight weeks after a preeclamptic pregnancy. However, these changes were not dependent on differences in blood pressure, small artery vasorelaxation, or cardiac and renal structure at this time point postpartum.

The mammalian heart is a major consumer of ATP and requires a constant supply of energy substrates for contraction. Not surprisingly, alterations of myocardial metabolism have been linked to the development of contractile dysfunction and heart failure. Therefore, unraveling the link between metabolism and contraction should shed light on some of the mechanisms governing cardiac adaptation or maladaptation in disease states. The isolated working rat heart preparation can be used to follow, simultaneously and in real time, cardiac contractile function and flux of energy providing substrates into oxidative metabolic pathways. The present protocol aims to provide a detailed description of the methods used in the preparation and utilization of buffers for the quantitative measurement of the rates of oxidation for glucose and fatty acids, the main energy providing substrates of the heart. The methods used for sample analysis and data interpretation are also discussed. In brief, the technique is based on the supply of 14C- radiolabeled glucose and a 3H- radiolabeled long-chain fatty acid to an ex vivo beating heart via normothermic crystalloid perfusion. 14CO2 and 3H2O, end byproducts of the enzymatic reactions involved in the utilization of these energy providing substrates, are then quantitatively recovered from the coronary effluent. With knowledge of the specific activity of the radiolabeled substrates used, it is then possible to individually quantitate the flux of glucose and fatty acid in the oxidation pathways. Contractile function of the isolated heart can be determined in parallel with the appropriate recording equipment and directly correlated to metabolic flux values. The technique is extremely useful to study the metabolism/contraction relationship in response to various stress conditions such as alterations in pre and after load and ischemia, a drug or a circulating factor, or following the alteration in the expression of a gene product.

Preeclampsia (PE) is a disorder associated with maternal hypertension, endothelial dysfunction and reductions in renal hemodynamics. Placental ischemia leads to increases in circulating maternal anti-angiogenic and pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) that induce endothelin-1 (ET-1), a potent vasoconstrictor. PE is also associated with depletion of nitric oxide, a facilitator of vasodilation, which binds to soluble guanylate cyclase (sGC), and synthesizes cGMP. In addition to promoting vasodilation, sGC activators and stimulators inhibit smooth muscle proliferation, leukocyte recruitment and platelet aggregation and are therefore, currently in clinical trials for treating cardiopulmonary disease. Although it is known that activating the nitric oxide signalling pathway induces vasodilation, its ability to inhibit TNF-α induced renal glomerular endothelial ET-1 production is unknown. We tested the hypothesis that cinaciguat, a sGC activator, attenuates ET-1 production induced by TNF-α in conditionally immortalized human glomerular endothelial cells. Cells were cultured; starved for 48 h; and treated for 12 h resulting in the following 4 groups having N=6/group: 1) Untreated, 2) 10 ng TNF-α 3) 10 μM cinaciguat + 10 ng TNF-α, and 4) 20 μM cinaciguat + 10 ng TNF-α. TNF-α (10 ng, 67.25±3.2 pg/mL) significantly increased ET-1 production compared to the untreated group (43.6±4.3 pg/mL, P

Background Unconjugated bilirubin (UCB), an endogenous antioxidant, may protect the heart against ischemia–reperfusion (I–R) injury. However, the ‘cardioprotective' potential of bilirubin therapy remains unclear. We tested whether pre- or post-ischemic treatment of ex vivo perfused hearts with bilirubin ditaurate (BRT) improves post-ischemic functional outcomes and myocardial oxidative damage. Methods Isolated Langendorff perfused hearts (male, Wistar rats) were treated with 50μM BRT for 30min before (Pre) or after (Post) 30min of zero-flow ischemia. Functional outcomes were monitored, with myocardial damage estimated from creatine kinase efflux, infarct size, and left ventricular lipid/protein oxidation assessed by measuring malondialdehyde and protein carbonyls. Ischemia induced contractile dysfunction and cellular injury, with both BRT treatments improving I–R outcomes. Results Final post-ischemic recoveries for left ventricular diastolic/developed pressures were significantly enhanced in treated groups: end-diastolic pressure (Control, 78±14, Pre, 51±15*, Post, 51±13mm Hg*); left ventricular developed pressure, (LVDP; Control 44±15, Pre, 71±19*, Post, 84±13mm Hg*). Myocardial injury/infarction (MI) was also significantly reduced with BRT treatment: post-ischemic creatine kinase efflux (Control, 1.24±0.41, Pre, 0.86±0.31*, Post, 0.51±0.29U/g/mL*; infarct size, Control, 67±17, Pre, 39±15*, Post, 22±11%*). These changes were accompanied by significantly reduced malondialdehyde and protein carbonyl content in Pre and Post treated hearts (*P vs. Control). Conclusions These data collectively reveal significant cardioprotection upon BRT treatment, with post-treatment being particularly effective. Significant reductions in infarct size and lipid and protein oxidation indicate a mechanism related to protection from oxidative damage and indicate the potential utility of this molecule as a post-MI treatment.

Sepsis is associated with abnormal host immune function in response to pathogen exposure, including endotoxin (lipopolysaccharide; LPS). Cytokines play crucial roles in the induction and resolution of inflammation in sepsis. Therefore, the primary aim of this study was to investigate the effects of endogenous tetrapyrroles, including biliverdin (BV) and unconjugated bilirubin (UCB) on LPS-induced cytokines in human blood. Biliverdin and UCB are by products of haem catabolism and have strong cytoprotective, antioxidant and anti-inflammatory effects. In the present study, whole human blood supplemented with BV and without was incubated in the presence or absence of LPS for 4 and 8 hours. Thereafter, whole blood was analysed for gene and protein expression of cytokines, including IL-1β, IL-6, TNF, IFN-γ, IL-1Ra and IL-8. Biliverdin (50 μM) significantly decreased the LPS-mediated gene expression of IL-1β, IL-6, IFN-γ, IL-1Ra and IL-8 (P

Introduction Women with a history of preeclampsia (PE) have an increased risk to develop cardiovascular and renal disease later in life. Pre-existing cardiovascular risk factors may play an important role, on the other hand the transient presence of placenta ischemia might induce persistent changes in the maternal cardiovascular system. Objective We aimed to assess whether exposure to placental ischemia during pregnancy enhances long-term effects on the maternal cardiovascular and renal systems in rats using the Reduced Uterine Perfusion Pressure (RUPP) model for PE. Methods At gestational day (gd) 14, Sprague Dawley rats were randomized to two groups: SHAM (n = 12) or RUPP (n = 21). The RUPP procedure involved partial clipping of the lower abdominal aorta and both ovarian arteries to reduce placental flow. Post delivery, rats were followed for 8 weeks after which we measured mean arterial pressure (MAP, carotid), GFR (transcutaneous, sinistrin), albuminuria (24-h) and cardiac function (cardiac ultrasound). All rats were sacrificed for tissue collection and mesenteric arteries were used for reactivity experiments to assess peripheral arterial function. Parametric data are presented as mean ± SD and non-parametric data as median (25–75 percentile), and were respectively analyzed with student T-test or Mann–Whitney U-test. Morphologic and transcriptional analyses are ongoing. Results The mean weight gain of the RUPP rats during pregnancy (gd13–gd19) was significantly lower compared to the SHAM operated rats [30 ± 18 g vs 63 ± 12; p Conclusions We show that exposure to experimental placenta ischemia is accompanied by subtle disturbances in maternal cardiac and renal function after recovery from PE. Our results indicate that placental ischemia itself can result in persistent changes in the cardiac and renal systems, although at this early stage no differences in vascular reactivity or blood pressure regulation were observed. Future studies should elucidate whether aging, a second hit or underlying disease aggravate target organ dysfunction after placental ischemia. Results Despite being all followed up for 27.5 yrs, the exposed women were older when they had their first pregnancy with and median age of 24.9 yrs ((5th;95th percentiles) (19.5;27.3)) vs. 24.6 yrs (19.4;27.3), p Conclusion A small extra vitamin D in fetal life from food fortification reduced risk of PE later in life. The effect was mainly seen among current smokers.