Vascular mechanical properties and endothelial function in pre-eclampsia with special reference to bilateral uterine artery notch

Spiral, uterine artery doppler and placental ultrasound in relation to preeclampsia

Preeclampsia (PE) is a multiorgan disorder that complicates around 2-8% of pregnancies and is a major cause of perinatal and maternal morbidity and mortality. PE is a clinical syndrome characterized by hypertension secondary to systemic inflammation, endothelial dysfunction, and syncytiotrophoblast stress leading to hypertension and multiorgan dysfunction. The uterine arteries are the main blood vessels that supply blood to the uterus. They give off branches and plays an important role in maintaining blood supply during pregnancy. The arcuate artery originates from the uterine artery and runs medially through the myometrium. The arcuate arteries divide almost directly into anterior and posterior branches, from which the radial artery leads directly to the uterine cavity during their course. Near the endometrium-myometrium junction, the radial artery generates spiral arteries within the basal layer and functional endometrium. The walls of radial and spiral arteries are rich in smooth muscle, which is lost when trophoblast cells invade and become large-caliber vessels. This physiological transformation of uteroplacental spiral arteries is critical for successful placental implantation and normal placental function. In normal pregnancy, the luminal diameter of the spiral arteries is greatly increased, and the vascular smooth muscle is replaced by trophoblast cells. This process and changes in the spiral arteries are called spiral artery remodeling. In PE, this genetically and immunologically governed process is deficient and therefore there is decreased vascular capacitance and increased resistance in the uteroplacental circulation. Furthermore, this defect in uteroplacental spiral artery remodeling is not only associated with early onset PE, but also with fetal growth restriction, placental abruption, and spontaneous premature rupture of membranes. Doppler ultrasound allows non-invasive assessment of placentation, while the flow impedance decreases as the pregnancy progresses in normal pregnancies, in those destined to develop preeclampsia the impedance is increased.

The association between assisted reproductive technology and cardiac remodeling in fetuses and early infants: a prospective cohort study

BACKGROUND

Limited data exist regarding the potential impact of assisted reproductive technology (ART) on cardiac remodeling. In particular, whether different ART techniques are related to different cardiac alterations remains unclear. We aimed to evaluate cardiac changes in fetuses and infants arising from ART and fetal cardiac alterations in fetuses conceived by specific ART procedures.

METHODS

This prospective and observational cohort study recruited 111 fetuses conceived by ART and 106 spontaneously conceived controls between December 2017 and April 2019. Echocardiography was performed between 28⁺⁰ and 32⁺⁶ weeks-of-gestation and at 0-2 and 6 months after birth.

RESULTS

A total of 88 ART fetuses and 85 controls were included in the final analysis. Compared to controls, ART fetuses demonstrated a globular enlarged left ventricle (LV) (LV sphericity index of mid-section, 2.29 ± 0.34 vs. 2.45 ± 0.39, P = 0.006; LV area, 262.33 ± 45.96 mm² vs. 244.25 ± 47.13 mm², P = 0.002), a larger right ventricle (RV) (RV area, 236.10 ± 38.63 mm² vs. 221.14 ± 42.60 mm², P = 0.003) and reduced LV systolic deformation (LV global longitudinal strain (GLS), -19.56% ± 1.90% vs. -20.65% ± 1.88%, P = 0.013; LV GLS rate S, -3.32 ± 0.36 s^-1 vs. -3.58 ± 0.39 s^-1, P = 0.023). There were no significant differences between the ART and control groups at postnatal follow-ups. Furthermore, we found fetal cardiac morphometry and function were comparable between different ART procedures. Compared to controls, the fetuses derived from various ART procedures all exhibited impairments in the LV GLS and the LV GLS rate S.

CONCLUSIONS

Our analysis demonstrated that subclinical cardiac remodeling and dysfunction were evident in ART fetuses, although these alterations did not persist in early infancy. In addition, various ART procedures may cause the same unfavorable changes in the fetal heart.

TRIAL REGISTRATION

This trial was registered at the Chinese Clinical Trial Registry ( www.chictr.org.cn ) ( ChiCTR1900021672 ) on March 4, 2019, retrospectively registered.

Variation in the uterine arteries Doppler parameters when obtained transvaginally or transabdominally at different sampling locations

INTRODUCTION

To evaluate differences in Doppler velocimetry parameters when the uterine arteries (UtA) are evaluated transabdominally (TA) at different sampling locations and transvaginally (TV).

MATERIALS AND METHODS

Five hundred and fifty-seven pregnant women were evaluated between 11 and 39 weeks of gestation. The mean UtA pulsatility index (PI) and prevalence of bilateral notching were obtained at four different locations: (1) TA just above the crossing with the iliac artery; (2) TA just below the crossing with the iliac artery; (3) TA well above approximately 3 cm away from the crossing with the iliac artery; and (4) TV at the point closest to the internal cervical os. Measurements obtained just above the external iliac artery were considered the standard for comparison. Differences among different locations per gestational week were calculated.

RESULTS

The mean UtA-PI and prevalence of bilateral notching were similar when the uterine arteries were sampled TA just above or just below the crossing with the external iliac artery. The mean UtA-PI values and prevalence of bilateral notching were significantly higher (p < .0001) when obtained TV and significantly lower when obtained 3 cm above the crossing with the external iliac artery (p = .004), as compared to the standard plane just above the crossing.

CONCLUSION

The mean UtA-PI and prevalence of bilateral notching vary significantly when the uterine arteries are sampled far above the crossing with the external iliac artery or when obtained transvaginally.Key MessageThe predictive performance of the uterine arteries during pregnancy can significantly vary in relation to the approach selected for evaluation and to the location of the Doppler sampling gate.

A Systematic Review of Vascular Structure and Function in Pre-eclampsia: Non-invasive Assessment and Mechanistic Links

Hypertensive disorders of pregnancy, such as pre-eclampsia, are known to be independently associated with the development of premature cardiovascular disease (CVD) in women. In pre-eclampsia, the placenta secretes excess anti-angiogenic factors into the maternal circulation, leading to widespread endothelial damage, and inflammation. This endothelial damage is evidenced to persist beyond the acute illness. However, whether it is permanent and responsible for the elevated rates of premature CVD seen in this at-risk group remains unclear. A systematic review of the available literature with respect to vascular structure and function prior to, during and after a pregnancy complicated by pre-eclampsia was performed. Studies non-invasively assessing vascular structure using carotid intima-media thickness (CIMT), retinal microvasculature caliber, CT coronary angiogram, or coronary calcium scores were included. Vascular function was assessed using brachial flow-mediated dilation (FMD), pulse wave analysis (PWA), and peripheral arterial tonometry (PAT). In total 59 articles were included (13 CIMT, 5 CTCA/Ca score, five retinal microvasculature, 27 FMD, 7 PAT, and 14 PWV/PWA), consisting of prospective and retrospective cohort, and case-control studies. Change in vascular structure was evidenced with significant increases in CIMT by 73-180 μm greater than that of non-affected women. This is tempered by other studies reporting resolution of structural changes postpartum, highlighting the need for further research. Accelerated coronary calcification and plaque deposition was identified, with greater rates of increased calcium scores and subclinical coronary artery disease shown by CTCA in women with a history of pre-eclampsia at 30 years postpartum. Impaired endothelial function was consistently reported prior to, during and immediately after pregnancy as evidenced by differences in FMD of 1.7-12.2% less than non-affected women, an increase in PWV by 13.2-26%, and reduced retinal microvascular caliber and arterial elasticity indices. The evidence was less conclusive for the persistence of long-term endothelial dysfunction. Understanding the underlying mechanistic links between pre-eclampsia and CVD is a key step to identifying targeted therapies aimed at "repairing the endothelium" and attenuating risk. This review has highlighted the need for a greater understanding of vascular structure and function following pre-eclampsia through high quality studies with large sample sizes, particularly in the longer postpartum period when clinical CVD disease starts to manifest.

A Systematic Review of Vascular Structure and Function in Pre-eclampsia: Non-invasive Assessment and Mechanistic Links

Hypertensive disorders of pregnancy, such as pre-eclampsia, are known to be independently associated with the development of premature cardiovascular disease (CVD) in women. In pre-eclampsia, the placenta secretes excess anti-angiogenic factors into the maternal circulation, leading to widespread endothelial damage, and inflammation. This endothelial damage is evidenced to persist beyond the acute illness. However, whether it is permanent and responsible for the elevated rates of premature CVD seen in this at-risk group remains unclear. A systematic review of the available literature with respect to vascular structure and function prior to, during and after a pregnancy complicated by pre-eclampsia was performed. Studies non-invasively assessing vascular structure using carotid intima-media thickness (CIMT), retinal microvasculature caliber, CT coronary angiogram, or coronary calcium scores were included. Vascular function was assessed using brachial flow-mediated dilation (FMD), pulse wave analysis (PWA), and peripheral arterial tonometry (PAT). In total 59 articles were included (13 CIMT, 5 CTCA/Ca score, five retinal microvasculature, 27 FMD, 7 PAT, and 14 PWV/PWA), consisting of prospective and retrospective cohort, and case-control studies. Change in vascular structure was evidenced with significant increases in CIMT by 73–180 μm greater than that of non-affected women. This is tempered by other studies reporting resolution of structural changes postpartum, highlighting the need for further research. Accelerated coronary calcification and plaque deposition was identified, with greater rates of increased calcium scores and subclinical coronary artery disease shown by CTCA in women with a history of pre-eclampsia at 30 years postpartum. Impaired endothelial function was consistently reported prior to, during and immediately after pregnancy as evidenced by differences in FMD of 1.7–12.2% less than non-affected women, an increase in PWV by 13.2–26%, and reduced retinal microvascular caliber and arterial elasticity indices. The evidence was less conclusive for the persistence of long-term endothelial dysfunction. Understanding the underlying mechanistic links between pre-eclampsia and CVD is a key step to identifying targeted therapies aimed at “repairing the endothelium” and attenuating risk. This review has highlighted the need for a greater understanding of vascular structure and function following pre-eclampsia through high quality studies with large sample sizes, particularly in the longer postpartum period when clinical CVD disease starts to manifest.

Carotid arterial wall stiffness correlates positively with impedance of the umbilical and uterine arteries in women with preeclampsia

PURPOSE

This study aimed to determine whether the stiffness of the arterial walls of women with preeclampsia (PE) differs from that of healthy controls and to evaluate its association with fetal and uterine artery Doppler variables and perinatal outcomes in PE.

METHODS

We enrolled 30 women with PE and 30 normotensive pregnant women. Carotid artery stiffness and Doppler variables of the uterine, umbilical, and fetal middle cerebral arteries and the ductus venosus were measured in both groups. Measurements of the common carotid artery were performed by the Aloka ultrasonic echo-tracking technique.

RESULTS

Stiffness of the carotid artery wall of women with PE was significantly higher than that of healthy controls. It was positively correlated with the pulsatility index of the uterine and umbilical arteries and negatively correlated with the cerebroplacental ratio in women with PE. In women with PE, the carotid artery augmentation index showed negative correlations with birth weight and Apgar score.

CONCLUSIONS

The stiffness of the carotid arteries of women with PE is increased, and this increase is positively correlated with the impedance of the umbilical and uterine arteries.

Strontium and its role in preeclampsia

BACKGROUND

Preeclampsia (PE) is considered a specific vascular disease in which endothelial dysfunction may be the crucial factor of its pathogenesis. It has been suggested that strontium (Sr) may play a role in the pathophysiology of PE. Our group established in a previous study the serum levels of Sr in healthy pregnancies, and the main aim of the present study was to evaluate Sr concentrations and oxidative status in preeclamptic women.

METHODS

The study population included women with early-onset PE (E-PE, n = 39), late-onset PE (L-PE, n = 67) and serial samples from a subset of preeclamptic women (PE-ss, n = 20). The control group included women with gestational hypertension (GH, n = 56) and healthy pregnancies (samples collected in the 1st (n = 50), 2nd (n = 51) and 3rd trimesters (n = 53)). Strontium, calcium (Ca), uric acid (UA), placental growth factor (PlGF), soluble fms-like tyrosine kinase 1 (sFlt-1), N-terminal pro-brain natriuretic peptide (NT-proBNP), lipid peroxidation and total antioxidant activity (TAA) were measured in these samples.

RESULTS

Mean Sr levels were significantly higher in PE than in control groups (p ≤ 0.0001). Calcium values were found to be significantly lower in E-PE compared to control groups (p = 0.03). Higher levels of NT-proBNP were found in PE vs. control groups (p < 0.001). sFlt-1/PlGF ratio was higher in E-PE compared to L-PE and GH (p < 0.001). Uric acid levels in PE were significantly higher than in control groups (p < 0.0001). There was a strong positive correlation between UA and Sr in the E-PE serial samples (r = 0.80, p < 0.0001). Lipid peroxidation and lipid peroxidation/TAA ratios were found to be higher in PE, with lower values of TAA.

CONCLUSION

The higher levels of Sr and the alterations of redox status found in preeclamptic women, along with the strong correlation between UA and Sr suggest that this element may be involved in the pathogenesis of PE.

The influence of prenatal exercise and pre-eclampsia on maternal vascular function

During healthy pregnancy, the cardiovascular system undergoes diverse adaptations to support adequate transfer of oxygen and nutrients from mother to fetus. In order to accommodate the large expansion of blood volume and associated cardiac output, the structure, mechanics, and function of the arteries are altered. Specifically, in healthy pregnancy there is a remodeling of arteries (increased angiogenesis and vasodilation), a generalized reduction in arterial stiffness (increased compliance), and an enhanced endothelial function. The development of pregnancy complications, specifically pre-eclampsia, is associated with poor placentation (decreased angiogenesis), increased arterial stiffness, and vascular dysfunction (reduced endothelial function). Many of the positive adaptations that occur in healthy pregnancy are enhanced in response to chronic exercise. Specifically, placental angiogenesis and endothelial function have been shown to improve to a greater extent in women who are active during their pregnancy compared with those who are not. Prenatal exercise may be important in helping to reduce the risk of vascular dysfunction in pregnancy. However, our knowledge of the vascular adaptations resulting from maternal exercise is limited. This review highlights maternal vascular adaptations occurring during healthy pregnancy, and contrasts the vascular maladaptation associated with pre-eclampsia. Finally, we discuss the role of prenatal exercise on vascular function in the potential prevention of vascular complications associated with pre-eclampsia.

Can flavonoid-rich chocolate modulate arterial elasticity and pathological uterine artery Doppler blood flow in pregnant women? A pilot study

INTRODUCTION

Dark chocolate has shown beneficial effects on cardiovascular health and might also modulate hypertensive complications in pregnancy and uteroplacental blood flow. Increased uteroplacental resistance is associated with systemic arterial stiffness. We aimed to investigate the short-term effect of flavonoid-rich chocolate on arterial stiffness and Doppler blood flow velocimetry indexes in pregnant women with compromised uteroplacental blood flow.

METHODS

Doppler blood flow velocimetry and digital pulse wave analysis (DPA) were performed in 25 women pregnant in the second and third trimesters with uterine artery (UtA) score (UAS) 3-4, before and after 3 days of ingestion of chocolate with high flavonoid and antioxidant contents. UtA pulsatility index (PI), UtA diastolic notching, UAS (semiquantitative measure of PI and notching combined), and umbilical artery PI were calculated, and DPA variables representing central and peripheral maternal arteries were recorded.

RESULTS

Mean UtA PI (p = .049) and UAS (p = .025) significantly decreased after chocolate consumption. There were no significant changes in UtA diastolic notching or any DPA indexes of arterial stiffness/vascular tone.

CONCLUSION

Chocolate may have beneficial effects on the uteroplacental circulation, but in this pilot study, we could not demonstrate effects on arterial vascular tone as assessed by DPA.

Impaired Flow-Mediated Dilation Before, During, and After Preeclampsia: A Systematic Review and Meta-Analysis

Endothelial dysfunction is believed to play a critical role in preeclampsia; however, it is unclear whether this dysfunction precedes the pregnancy or is caused by pathophysiological events in early pregnancy. It is also unclear for how long vascular dysfunction may persist postpartum and whether it represents a mechanism linking preeclampsia with future cardiovascular disease. Our objective was to determine whether women with preeclampsia had worse vascular function compared with women who did not have preeclampsia by performing a systematic review and meta-analysis of studies that examined endothelial dysfunction using flow-mediated dilation. We included studies published before May 29, 2015, that examined flow-mediated dilation before, during, or after preeclampsia. Differences in flow-mediated dilation between study groups were evaluated by standardized mean differences. Out of 610 abstracts identified through PubMED, EMBASE, and Web of Science, 37 studies were eligible for the meta-analysis. When compared with women who did not have preeclampsia, women who had preeclampsia had lower flow-mediated dilation before the development of preeclampsia (≈20-29 weeks gestation), at the time of preeclampsia, and for 3 years postpartum, with the estimated magnitude of the effect ranging between 0.5 and 3 standard deviations. Similar effects were observed when the analysis was limited to studies that excluded women with chronic hypertension, smokers, or both. Vascular dysfunction predates preeclampsia and may contribute to its pathogenesis. Future studies should address whether vascular changes that persist after preeclamptic pregnancies may represent a mechanistic link with increased risk for future cardiovascular disease.

Flow-mediated dilation: can new approaches provide greater mechanistic insight into vascular dysfunction in preeclampsia and other diseases?

Endothelial dysfunction is a key feature of preeclampsia and may contribute to increased cardiovascular disease risk years after pregnancy. Flow-mediated dilation (FMD) is a non-invasive endothelial function test that predicts cardiovascular event risk. New protocols allow researchers to measure three components of the FMD response: FMD, low flow-mediated constriction, and shear stimulus. This review encourages researchers to think beyond "low FMD" by examining how these three components may provide additional insights into the mechanisms and location of vascular dysfunction. The review then examines what FMD studies reveal about vascular dysfunction in preeclampsia while highlighting opportunities to gain greater mechanistic insight from new protocols. Studies using traditional protocols show that FMD is low in mid-pregnancy prior to preeclampsia, at diagnosis, and for 3 years post-partum. However, FMD returns to normal by 10 years post-partum. Studies using new protocols are needed to gain more mechanistic insight.

Expression of osteoprotegerin in placenta and its association with preeclampsia

BACKGROUND

Osteoprotegerin (OPG), a key regulatory factor in bone metabolism, was documented also a potential pro-angiogenic factor, which acts an important role in protecting vascular endothelial cells. Since preeclampsia has gradually been employed to be vascular diseases, we speculated that OPG might be associated with preeclampsia. The study was to evaluate the level of OPG protein and mRNA in placenta, and investigate the relationship between OPG and the pathogenesis of preeclampsia.

METHODOLOGY/PRINCIPAL FINDINGS

Placental specimens from 30 term normal pregnancy, 30 severe preeclampsia and 30 mild cases were studied. The expression and levels of OPGs' protein and mRNA were detected by immunohistochemistry, western blot analysis and real-time quantitative PCR analysis respectively. The expression of OPG protein was found in cytoplasm of placenta cytotrophoblasts and syncytiotrophoblasts in three groups. There were no significant differences of OPG protein between the maternal and fetal side in each group. The OPG protein and mRNA levels in severe preeclampsia were significantly higher than those in mild cases and normal pregnancy. However, there were no markedly differences of the OPG protein and mRNA levels between term delivery and preterm delivery in severe cases. In preeclampsia, the OPG protein and mRNA level was positively correlated with systolic blood pressure and 24 h urinary protein respectively.

CONCLUSIONS/SIGNIFICANCE

OPG protein and mRNA level in placentas of preeclampsia were found abnormal compared with normal pregnancy. In preeclampsia, the OPG protein and mRNA levels were closely related with its important clinical parameters. Taken together, OPG might be closely correlated with the pathogenesis of preeclampsia.

Antioxidants to enhance fertility: role of eNOS and potential benefits

The use of antioxidants is now often used as a pharmacological adjunct to limit infertility. Indeed, the lay public rightly perceives oxidative stress and, thus, antioxidant treatment as important modulators of infertility. While the direct effects of antioxidant treatment on the quality of semen and oocytes are still under investigation, a significant body of evidence points to loss of vascular tone as a root-cause of erectile dysfunction and, possibly, alterations to female reproduction. In this article, we will critically review the often neglected link between vascular dysfunction and infertility. A particular emphasis will be on the potential use of antioxidants to increase fertility and promote conception.

Assessment of the cardioankle vascular index in pregnant women complicated with hypertensive disorders

It was previously reported that the brachial-ankle pulse wave velocity (baPWV) is elevated in preeclamptic women. However, baPWV is strongly affected by blood pressure. Recently, a new index of vascular stiffness, the cardioankle vascular index (CAVI), was developed. CAVI is thought to be an index independent of blood pressure. We assessed CAVI in normotensive and hypertensive pregnant women. We studied a total of 109 Japanese women consisting of 23 nonpregnant healthy women (group A), 45 normotensive pregnant women (group B), 28 pregnant women complicated with established preeclampsia (group C), and 13 pregnant women with chronic hypertension (group D). The subject remained supine while the blood pressure, baPWV, and CAVI were recorded. No significant difference in baPWV was present between groups C and D, but the difference in CAVI was significantly high in group D. We believe that we can distinguish the vessel structural change between chronic hypertension and preeclampsia through simultaneous baPWV and CAVI measurements.

The relationship between brachial artery flow-mediated dilatation, high sensitivity C-reactive protein, and uterine artery doppler velocimetry in women with pre-eclampsia

PURPOSE

To investigate serum high sensitivity C-reactive protein (hs-CRP) levels and endothelial function in pregnancies complicated by pre-eclampsia and to clarify their relationship with uterine artery Doppler velocimetry.

METHODS

A cross-sectional study was carried out in 70 pregnant women (35 patients with pre-eclampsia and 35 age-matched normotensive healthy pregnant women) during the third trimester of pregnancy. The maternal levels of serum hs-CRP were determined in all cases by immunonephelometry. Uterine artery Doppler velocimetry was performed. Flow-mediated dilatation was measured by sonography of the brachial artery for the assessment of endothelial function.

RESULTS

Serum hs-CRP levels were higher in the pre-eclamptic group than in the normotensive group. hs-CRP levels were positively correlated with mean arterial pressure. Eleven patients with pre-eclampsia had abnormal uterine artery Doppler velocimetry. hs-CRP levels were significantly higher in pre-eclamptic patients with than without abnormal uterine artery Doppler velocimetry. Endothelial function was inversely correlated with hs-CRP levels and mean arterial pressure.

CONCLUSIONS

These findings suggest that maternal serum hs-CRP levels increase with the severity of pre-eclampsia, reflecting endothelial dysfunction and constituting a potential marker of pathological utero-placental perfusion, with a high risk for fetal growth restriction.

Maternofetal pharmacokinetics of a gadolinium chelate contrast agent in mice

PURPOSE

To determine the maternofetal pharmacokinetics of gadoterate meglumine in mice during the first 48 hours following maternal intravenous injection of a high dose of 0.5 mmol of gadolinium per kilogram.

MATERIALS AND METHODS

All the studies complied with French law and the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. Balb/C mice (n = 23) at 16 days of gestation were examined for 48 hours after maternal intravenous administration of 0.5 mmol gadolinium per kilogram of gadoterate meglumine. Gadolinium concentration in the placentas, fetuses, and amniotic fluid was determined by using mass spectrometry, and the total placental and fetal gadolinium content was calculated. Gadoterate meglumine half-life in the different compartments was estimated with one- and two-compartment models. Kruskal-Wallis and Wilcoxon signed-rank tests were used to compare the pharmacokinetic profiles.

RESULTS

Gadoterate meglumine passed the placental barrier, entering the fetuses and amniotic fluid before being redistributed back to the mother. The placental gadolinium concentration showed two-compartmental decay, with a first half-life of distribution of 47 minutes and a second half-life of elimination of 107 hours. The half-lives in the fetuses and amniotic fluid were, respectively, 4 and 5 hours and followed a monocompartmental model after the initial peak. The maximal gadolinium fetal concentration (31.8 nmol/g) was observed 30 minutes after injection, which corresponded to a total fetal content of 0.077% of the injected dose.

CONCLUSION

In mice, gadoterate meglumine, an extracellular nonspecific gadolinium chelate contrast medium, passed the placenta before being redistributed back to the mother, resulting in undetectable fetal concentrations after 48 hours.

Uterine venous blood flow in normal and complicated pregnancies: a methodological study

OBJECTIVE

To investigate the possibility of recording Doppler flow signals from the maternal uterine veins (UtVs) during pregnancy and to assess the relationship between UtV signals and other Doppler parameters as well as pregnancy outcomes.

METHODS

Transabdominal Doppler ultrasound examination of the UtVs on both sides of the uterus was performed in 40 normal and 44 high-risk singleton pregnancies at 23-39 weeks' gestation. The UtV was identified using color Doppler imaging and the flow velocity signals of the UtV and uterine artery (UtA) were recorded. Morphological examination of the placenta was carried out in 45 of the pregnancies (14 uncomplicated and 31 high-risk pregnancies).

RESULTS

Flow-velocity signals of the UtVs were recorded from at least one side of the uterus in all patients (success rate of 81 and 89% for the right and left UtV, respectively). Three types of flow-velocity pattern were identified: continuous non-pulsatile flow (Type I, n = 70), pulsatile flow with a notch touching the zero line (Type II, n = 6) and pulsatile flow with absent flow signals for part of the heart cycle (Type III, n = 8). The UtA pulsatility index was significantly higher in women with UtV Types II and III than in those with UtV Type I (P = 0.039). Similarly, UtV Types II and III were more often found in pregnancies with bilateral UtA notching (P = 0.013) and with UtA score 3-4 (P = 0.024) than in those with normal UtA. No statistically significant association was found between the UtV flow pattern and abnormal histopathological findings in the placenta, or between the UtV and umbilical artery findings.

CONCLUSION

It is possible to record Doppler signals from the UtVs in the late second and third trimesters of pregnancy. Pulsatile flow-velocity patterns of the UtVs are associated with abnormal UtA Doppler findings.

Current world literature

This bibliography is compiled by clinicians from the journals listed at the end of this publication. It is based on literature entered into our database between 1 February 2008 and 31 January 2009 (articles are generally added to the database about two and a half months after publication). In addition, the bibliography contains every paper annotated by reviewers; these references were obtained from a variety of bibliographic databases and published between the beginning of the review period and the time of going to press. The bibliography has been grouped into topics that relate to the reviews in this issue.

Early detection of lesions of dorsal artery of foot in patients with type 2 diabetes mellitus by high-frequency ultrasonography

This study evaluated the value of high-frequency ultrasonograpy for early detection of dorsal artery of foot in patients with type 2 diabetes mellitus (MD). Eighty subjects including 40 patients with type 2 MD (T2DM group) and 40 healthy volunteers (NC group) were recruited. The intima-media thickness (IMT), the inner diameter and the perfusion of dorsal artery of foot were measured by using high-frequency ultrasonograpy. Meanwhile, the parameters of vascular elasticity, including stiffness parameter (beta), pressure-strain elastic modulus (Erho), arterial compliance (AC), augment index (AI), and pulse wave conducting velocity (PWVbeta) were detected by means of echo-tracking technique. The results showed that no significant difference was found in the IMT, systolic diameter (Ds), diastolic diameter (Dd) and peak systolic velocity (PSV) between T2DM and NC groups. Erho and PWVbeta were increased, and AC was decreased in T2DM group as compared with those in NC group with the differences being significant (P<0.05 for all). There was no significant difference in beta and AI between T2DM and NC groups. It was concluded that high-frequency ultrasonography in combination with echo-tracking technique is sensitive and non-invasive, and can be used for early detection of sclerosis of the lower extremity artery in patients with type 2 MD.

Expressions of adiponectin receptors in placenta and their correlation with preeclampsia

BACKGROUND

Adiponectin and its receptors, adiponectin receptor 1 (Adipo-R1) and adiponectin receptor 2 (Adipo-R2), may contribute to preeclampsia; however, the reports up to date are conflicting. Here we further explore this issue.

METHODS

We studied 20 pregnant women with term normal pregnancy, 22 women with severe preeclampsia, and 12 mild cases. The levels of Adipo-Rs' protein and messenger RNA (mRNA) were detected by immunohistochemistry and real-time quantitative polymerized chain reaction (PCR) analysis, respectively.

RESULTS

The expression of Adipo-R2, but not Adipo-R1, was observed in the cytoplasm of both placental cytotrophoblasts and syncytiotrophoblasts of the mild preeclempsia, severe cases and normal pregnancy group. There was no significant difference of Adipo-R2 protein level between the maternal side and the fetal side in each group (all P > .05). Adipo-R2 protein and mRNA levels in severe preeclamptic group were significantly higher than those of mild cases (P < .001) and normal pregnancy group (P < .001). There was also no significant difference of Adipo-R2 protein and mRNA levels between term delivery and preterm delivery in severe preeclamptic group (P > .05). Nonetheless, both the protein and mRNA levels were significantly higher in comparison to those of the normal group (P < .05).

CONCLUSIONS

The abnormality of Adipo-R2 may be associated with the pathogenesis of preeclampsia.

Mechanism of development of pre-eclampsia linking breathing disorders to endothelial dysfunction

High blood pressure is an important component of pre-eclampsia. The underlying mechanism of development of hypertension in pre-eclampsia is complicated and still remains obscure. Several theories have been advanced including endothelial dysfunction, uteroplacental insufficiency leading to generalized vasoconstriction, increased cardiac output, and sympathetic hyperactivity. Increased blood flow and pressure are thought to lead to capillary dilatation, which damages end-organ sites, leading to hypertension, proteinuria and edema. Additional theories have been put forward based on epidemiological research, implicating immunological and genetic factors. None of these theories have been substantiated. Based on a review of literature this paper postulates that the initiating event for the development of pre-eclampsia is intermittent hypoxia associated with irregular breathing during sleep, hypoapnea, apnea, inadequate respiratory excursions during the waking hours and inadequate cardiopulmonary synchronization (abnormal sympatho-vagal balance).

Differential [Ca2+]i signaling of vasoconstriction in mesenteric microvessels of normal and reduced uterine perfusion pregnant rats

Vascular resistance and blood pressure (BP) are reduced during late normal pregnancy (Norm-Preg). In contrast, studies in human preeclampsia and in animal models of hypertension in pregnancy (HTN-Preg) have suggested that localized reduction in uterine perfusion pressure (RUPP) in late pregnancy is associated with increased systemic vascular resistance and BP; however, the vascular mechanisms involved are unclear. Because Ca2+ is a major determinant of vascular contraction, we hypothesized that the intracellular free calcium concentration ([Ca2+]i) signaling of vasoconstriction is differentially regulated in systemic microvessels during normal and RUPP in late pregnancy. Pressurized mesenteric microvessels from Norm-Preg and RUPP rats were loaded with fura 2 in preparation for simultaneous measurement of diameter and [Ca2+]i (presented as fura 2 340/380 ratio). Basal [Ca2+]i was lower in RUPP (0.73 +/- 0.03) compared with Norm-Preg rats (0.82 +/- 0.03). Membrane depolarization by 96 mM KCl, phenylephrine (Phe, 10(-5) M), angiotensin II (ANG II, 10(-7) M), or endothelin-1 (ET-1, 10(-7) M) caused an initial peak followed by maintained vasoconstriction and [Ca2+]i. KCl caused similar peak vasoconstriction and [Ca2+]i in Norm-Preg (45.5 +/- 3.3 and 0.89 +/- 0.02%) and RUPP rats (46.3 +/- 2.1 and 0.87 +/- 0.01%). Maximum vasoconstriction to Phe, ANG II, and ET-1 was not significantly different between Norm-Preg (28.6 +/- 4.8, 32.5 +/- 6.3, and 40 +/- 4.6%, respectively) and RUPP rats (27.8 +/- 5.9, 34.4 +/- 4.3, and 38.8 +/- 4.1%, respectively). In contrast, the initial Phe-, ANG II-, and ET-1-induced 340/380 ratio ([Ca2+]i) was reduced in RUPP (0.83 +/- 0.02, 0.82 +/- 0.02, and 0.83 +/- 0.03, respectively) compared with Norm-Preg rats (0.95 +/- 0.04, 0.93 +/- 0.01, and 0.92 +/- 0.02, respectively). Also, the [Ca2+]i-vasoconstriction relationship was similar in KCl-treated but shifted to the left in Phe-, ANG II-, and ET-1-treated microvessels of RUPP compared with Norm-Preg rats. The lower agonist-induced [Ca2+]i signal of vasoconstriction and the leftward shift in the [Ca2+]i-vasoconstriction relationship in microvessels of RUPP compared with Norm-Preg rats suggest activation of [Ca2+]i sensitization pathway(s). The similarity in vasoconstriction in RUPP and Norm-Preg rats suggests that such a [Ca2+]i sensitization pathway(s) may also provide a feedback effect on Ca2+ mobilization/homeostatic mechanisms to protect against excessive vasoconstriction in systemic microvessels during RUPP in late pregnancy.