Aortic Intima Media Thickness in Fetuses and Children With Intrauterine Growth Restriction

Estimation of prenatal aorta intima-media thickness from ultrasound examination

Prenatal events such as intrauterine growth restriction and increased cardiovascular risk in later life have been shown to be associated with an increased intima-media thickness (aIMT) of the abdominal aorta in the fetus. In order to assess and manage atherosclerosis and cardiovascular disease risk in adults and children, in recent years the measurement of abdominal and carotid artery thickness has gained a growing appeal. Nevertheless, no computer aided method has been proposed for the analysis of prenatal vessels from ultrasound data, yet. To date, these measurements are being performed manually on ultrasound fetal images by skilled practitioners. The aim of the presented study is to introduce an automatic algorithm that identifies abdominal aorta and estimates its diameter and aIMT from routine third trimester ultrasonographic fetal data.The algorithm locates the aorta, then segments it and, by modeling the arterial wall longitudinal sections by means of a gaussian mixture, derives a set of measures of the aorta diameter (aDiam) and of the intima-media thickness (aIMT). After estimating the cardiac cycle, the mean diameter and the aIMT at the end-diastole phase are computed.Considering the aIMT value for each subject, the correlation between automatic and manual end-diastolic aIMT measurements is 0.91 in a range of values 0.44-1.10 mm, corresponding to both normal and pathological conditions. The automatic system yields a mean relative error of 19%, that is similar to the intra-observer variability (14%) and much lower that the inter-observer variability (42%).The correlation between manual and automatic measurements and the small error confirm the ability of the proposed system to reliably estimate aIMT values in prenatal ultrasound sequences, reducing measurement variability and suggesting that it can be used for an automatic assessment of aIMT.

Early origins of adult disease: low birth weight and vascular remodeling

Cardiovascular diseases (CVD) and diabetes still represent the main cause of mortality and morbidity in the industrialized world. Low birth weight (LBW), caused by intrauterine growth restriction (IUGR), was recently known to be associated with increased rates of CVD and non-insulin dependent diabetes in adult life (Barker's hypothesis). Well-established animal models have shown that environmentally induced IUGR (diet, diabetes, hormone exposure, hypoxia) increases the risk of a variety of diseases later in life with similar phenotypic outcomes in target organs. This suggests that a range of disruptions in fetal and postnatal growth may act through common pathways to regulate the developmental programming and produce a similar adult phenotype. The identification of all involved signaling cascades, underlying the physiopathology of these damages in IUGR fetuses, with their influence on adult health, is still far from satisfactory. The endothelium may be important for long-term remodeling and in the control of elastic properties of the arterial wall. Several clinical and experimental studies showed that IUGR fetuses, neonates, children and adolescents present signs of endothelial dysfunction, valuated by aorta intima media thickness, carotid intima media thickness and stiffness, central pulse wave velocity, brachial artery flow-mediated dilation, laser Doppler skin perfusion and by the measure of arterial blood pressure. In utero identification of high risk fetuses and long-term follow-up are necessary to assess the effects of interventions aimed at preventing pregnancy-induced hypertension, reducing maternal obesity, encouraging a healthy life style and preventing childhood obesity on adult blood pressure and cardiovascular disease in later life.

Intima-media thickness measurements in the fetus and mother during pregnancy: a feasibility study

Fetal intima-media thickness (IMT) has been suggested as a marker of pre-clinical atherosclerosis, and maternal IMT could be altered through dynamic circumstances related to pregnancy. We investigated the feasibility of measurement of IMT at four pre-defined fetal and four pre-defined maternal arterial locations to determine vascular changes that could be associated with impaired vascular function. IMT was measured from the first to third trimester (12-34 wk), in 38 low-risk pregnancies. We imaged a 10-mm region of interest using a Mindray (Shenzhen, China) high-resolution ultrasound machine with automated IMT measurement software. Fetal abdominal aorta IMT was measurable during the second trimester in 71% and during the third trimester in 100% of the case, and umbilical artery IMT was measurable in 50% and 82% of cases during the second and third trimesters, respectively. Fetal IMT measurements were not possible during the first trimester. It was not often feasible to measure the IMT of the fetal common carotid artery, fetal renal artery and maternal iliac artery (maximal 20% of cases). Maternal common carotid artery, abdominal aorta and uterine artery IMTs were measurable throughout pregnancy. There was a significant relation between gestational age and IMT in the umbilical artery (p = 0.03) and a significant relation between body mass index and IMT in the maternal common carotid artery (p = 0.01). IMT measurements are feasible in some maternal and fetal vessels of interest. Further studies are underway to obtain more insight into vascular development during normal and pathologic pregnancies.

Adiponectin levels are reduced while markers of systemic inflammation and aortic remodelling are increased in intrauterine growth restricted mother-child couple

AIM OF THE STUDY

To investigate the relationships between the adipocytokine levels, markers of inflammation, and vascular remodelling in pregnancies complicated by intrauterine growth restriction (IUGR).

MATERIALS AND METHODS

This was a retrospective study. One hundred and forty pregnant patients were enrolled. Adiponectin, leptin, tumor necrosis factor α (TNFα), interleukin-6 (IL-6), and C reactive protein (CRP) were assessed in IUGR, small for gestational age (SGA), and appropriate for gestational age (AGA) mother-child couples at delivery. IUGR and SGA fetuses were defined as fetuses whose estimated fetal weight (EFW) was below 10th percentile for gestational age with and without umbilical artery (UA) Doppler abnormalities, respectively. Fetal aorta intima media thickness (aIMT) was evaluated by ultrasound in the same fetal groups. Data were analyzed by R (version 2.15.2).

RESULTS

There were 37 IUGR mother-child couples, 33 SGA, and 70 AGA. Leptin, TNFα, IL-6, and CRP serum levels were higher in IUGR pregnant patients (P < 0.05). Adiponectin levels were significantly reduced in IUGR fetuses compared to SGA and AGA, while leptin, TNFα, and IL-6 levels were higher in IUGR group (P ≤ 0.05). Fetal aIMT was significantly higher in IUGR (P < 0.05) and in this group there was a negative correlation between aIMT and adiponectin/leptin ratio (A/L ratio) (P < 0.05) and between adiponectin and IL-6 levels (P < 0.05).

CONCLUSIONS

In conclusion, compared to SGA and AGA, IUGR fetuses had reduced circulating levels of adiponectin and elevated measures of aIMT and several inflammatory markers. Moreover, adiponectin levels were negatively correlated with aIMT in IUGR fetuses suggesting a possible causal link between reduced adiponectin and vessel remodelling.

A review on the genetic, environmental, and lifestyle aspects of the early-life origins of cardiovascular disease

This article is a comprehensive review on developmental origins of health and disease regarding various factors related to the origins of cardiovascular diseases from early life. It presents a summary of the impacts of various factors such as epigenetics; gene-environment interaction; ethnic predisposition to cardiovascular diseases and their underlying risk factors; prenatal factors; fetal programming; maternal weight status and weight gain during pregnancy; type of feeding during infancy; growth pattern during childhood; obesity; stunting; socioeconomic status; dietary and physical activity habits; active, secondhand, and thirdhand smoking, as well as environmental factors including air pollution and global climate change on the development and progress of cardiovascular diseases and their risk factors. The importance of early identification of predisposing factors for cardiovascular diseases for primordial and primary prevention of cardiovascular diseases from early life is highlighted.

Carotid arterial intima–media thickness and arterial stiffness in pre-eclampsia: analysis with a radiofrequency ultrasound technique

OBJECTIVE

Whether arterial elasticity is reduced in preeclampsia has been investigated only rarely. This study aimed to characterize in vivo the carotid arterial intima–media thickness (IMT) and mechanical properties in women with pre-eclampsia by employing a radiofrequency ultrasound technique.

METHODS

We included 22 late-onset pre-eclamptic pregnant women and 28 normotensive pregnant women who were matched for age (29 ± 6 vs. 27 ± 3, P=0.09) and gestational age (36.0 ± 3.2 vs. 35.8 ± 2.4 weeks, P=0.802). All women were nulliparous with singleton pregnancy. The pre-eclamptic women had a significantly higher arterial pressure than did the normotensive women (P<0.0001). All women underwent right common carotid arterial measurements with an ultrasound machine equipped with automatic Quality IMT (QIMT) and Quality Arterial Stiffness (QAS) capability. At follow-up examination 18 months after parturition, measurements were repeated in 10 of the pre-eclamptic women and 11 of the normotensive women.

RESULTS

In pre-eclamptic compared with normotensive pregnancy, carotid arterial IMT (459 ± 95 vs. 351 ± 85 μm, P=0.0001), internal diameter (7.8 ± 0.5 vs. 7.2 ± 0.4 mm, P<0.0001), pulse wave velocity (7.1 ± 1.7 vs. 6.0 ± 1.5 m/s, P=0.007), augmentation index (7.9 ± 9.2 vs. −5.0 ± 5.6%, P<0.0001) and arterial wall tension (55.0 ± 6.5 vs. 38.6 ± 4.9 mmHg/cm, P<0.0001) were significantly greater, and the distensibility coefficient (0.020 ± 0.009 vs. 0.029 ± 0.011 1/kPa, P=0.006) was significantly smaller, remaining so after adjusting for body mass index and carotid arterial pressure. Eighteen months after parturition, carotid arterial internal diameter, pressure and wall tension remained greater in the pre-eclamptic group.

CONCLUSION

Carotid arterial remodeling, including changes in arterial internal diameter and wall thickness, and arterial stiffening occur in pre-eclampsia but this may reverse, to some extent, postpartum. QIMT and QAS techniques together could provide a comprehensive assessment of carotid arterial remodeling.

Fetal echocardiography and pulsed-wave Doppler ultrasound in a rabbit model of intrauterine growth restriction

Fetal intrauterine growth restriction (IUGR) results in abnormal cardiac function that is apparent antenatally due to advances in fetoplacental Doppler ultrasound and fetal echocardiography. Increasingly, these imaging modalities are being employed clinically to examine cardiac function and assess wellbeing in utero, thereby guiding timing of birth decisions. Here, we used a rabbit model of IUGR that allows analysis of cardiac function in a clinically relevant way. Using isoflurane induced anesthesia, IUGR is surgically created at gestational age day 25 by performing a laparotomy, exposing the bicornuate uterus and then ligating 40-50% of uteroplacental vessels supplying each gestational sac in a single uterine horn. The other horn in the rabbit bicornuate uterus serves as internal control fetuses. Then, after recovery at gestational age day 30 (full term), the same rabbit undergoes examination of fetal cardiac function. Anesthesia is induced with ketamine and xylazine intramuscularly, then maintained by a continuous intravenous infusion of ketamine and xylazine to minimize iatrogenic effects on fetal cardiac function. A repeat laparotomy is performed to expose each gestational sac and a microultrasound examination (VisualSonics VEVO 2100) of fetal cardiac function is performed. Placental insufficiency is evident by a raised pulsatility index or an absent or reversed end diastolic flow of the umbilical artery Doppler waveform. The ductus venosus and middle cerebral artery Doppler is then examined. Fetal echocardiography is performed by recording B mode, M mode and flow velocity waveforms in lateral and apical views. Offline calculations determine standard M-mode cardiac variables, tricuspid and mitral annular plane systolic excursion, speckle tracking and strain analysis, modified myocardial performance index and vascular flow velocity waveforms of interest. This small animal model of IUGR therefore affords examination of in utero cardiac function that is consistent with current clinical practice and is therefore useful in a translational research setting.

Investigating the relationship between prenatal growth and postnatal outcomes: a systematic review of the literature

Theories regarding the relationship between pre- and postnatal growth and programming of health have been based on characteristics at birth, with little or no reference to the patterns of growth occurring in utero. Review of the literature to identify studies using ultrasonographically obtained fetal dimensions to track prenatal growth and relate these patterns of growth to postnatal anthropometry and cardiovascular and metabolic risk factors. Review of Medline, Scopus and Proquest for studies reporting on ultrasonographically derived estimates of fetal growth and their association with postnatal anthropometry, body composition or cardiovascular and metabolic risk factors. Quality of papers were assessed using the method developed by Downs and Black. Twenty-nine studies met the inclusion criteria, with a mean score of high quality. Twenty of the studies had follow-up in infancy, five in childhood, three in adolescence and one in adulthood. The associations observed suggest that centile tracking may occur early in pregnancy though whether this is as early as the first trimester is uncertain. The second trimester may be a critical period for the programming of blood pressure and abdominal circumference may be the most sensitive fetal dimension to indicate any programming.

Selective intrauterine growth restriction in monochorionic twin pregnancies: markers of endothelial damage and metabolomic profile

The aim of this study was to assess the aorta-intima thickness (aIT) and serum metabolomic profile in selective intrauterine growth-restricted (sIUGR) monochorionic diamniotic (MCDA) twin fetuses presenting Doppler velocimetry alterations. Fetal abdominal aIT was measured by ultrasound at 32 weeks of gestation, enrolling 24 MCDA twin fetuses (8 sIUGR and 16 controls). sIUGR twin fetuses were classified into two groups: Group 1 consisted of sIUGR with abnormal umbilical artery (UA) Doppler waveforms and Group 2 included sIUGR with normal UA Doppler. Group 3 were control fetuses appropriate for gestational age (AGA). Fetal blood samples were obtained from the umbilical vein immediately after fetal extraction. A non-targeted metabolomic profiling investigated fetal metabolism alterations by using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Median fetal aIT was significantly larger in Group 1 (median value = 0.9 mm; range = 0.8-1.0 mm; p < .002) and Group 2 (median value = 0.8 mm; range = 0.7-0.8 mm; p < .002) than in AGA Group 3 (median value = 0.5 mm; range = 0.4-0.6 mm; p < .002). Metabolomic analyses, performed on four sIUGR cases (Group 1) compared with four AGA co-twins, showed an upregulation of phenylalanine, sphingosine, glycerophosphocholine, and choline, and a downregulation of valine, tryptophan, isoleucine, and proline sIUGR Group 1 compared with AGA. Although for metabolomics data only a statistical tendency (and not a statistical significance) was reached due to the small sample size, we believe that our results represent a valid starting point for further in-depth metabolomic and proteomic investigations of sIUGR in MCDA fetuses.

Birth weight and carotid artery intima-media thickness

OBJECTIVES

To determine the association between birth weight and carotid artery intima-media thickness (CIMT), a measure of atherogenesis, in a population of 11-year-old children.

STUDY DESIGN

CIMT measured by high-resolution ultrasound, and birth registry data were available for 670 children of the Southern California Children's Health Study. Multivariate regression analyses were performed to investigate the association between birth weight and CIMT, with adjustment for child's health status and lifestyle, pregnancy information, and parental health.

RESULTS

Mean CIMT was 0.57 mm (SD 0.04). We found a nonlinear association between birth weight and CIMT, with an increase in CIMT of 0.014 mm in the fifth (P value .01) compared with the third birth weight quintile. These associations were robust in subsample analyses in children considered normal-weight by gestational age or in term-born children. No significant association with CIMT was found for the lowest quintile.

CONCLUSIONS

Greater birth weight was significantly associated with increased CIMT at age 11 years. No evidence for an impact of lower birth weight was found. The predictive value of childhood CIMT on future cardiovascular outcomes is largely unknown, but strong associations between childhood cardiovascular disease risk factors and adult vascular disease suggest that increased CIMT in childhood may be clinically important.

Developmental programming of cardiovascular disease by prenatal hypoxia

It is now recognized that the quality of the fetal environment during early development is important in programming cardiovascular health and disease in later life. Fetal hypoxia is one of the most common consequences of complicated pregnancies worldwide. However, in contrast to the extensive research effort on pregnancy affected by maternal nutrition or maternal stress, the contribution of pregnancy affected by fetal chronic hypoxia to developmental programming is only recently becoming delineated and established. This review discusses the increasing body of evidence supporting the programming of cardiac susceptibility to ischaemia and reperfusion (I/R) injury, of endothelial dysfunction in peripheral resistance circulations, and of indices of the metabolic syndrome in adult offspring of hypoxic pregnancy. An additional focus of the review is the identification of plausible mechanisms and the implementation of maternal and early life interventions to protect against adverse programming.

Aortic wall thickness and amniotic fluid albuminuria in growth-restricted twin fetuses

BACKGROUND AND OBJECTIVE

Intrauterine growth restriction (IUGR) may be associated with significantly higher aortic intima-media thickening (aIMT) values. It is unknown if fetal aIMT is associated with glomerulosclerosis and amniotic albuminuria in utero.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

Fetal abdominal aIMT and amniotic albumin/creatinine ratio (ACR) were measured in 126 individual twin fetuses, recruited by the Obstetrics and Gynaecology Clinics of the University of Padua (Italy) Medical Center. The IUGR twin fetuses were classified into two groups: Group A were those fetuses whose estimated fetal weight (EFW) was <10th percentile with pulsatility index >2 SD and Group B were those fetuses whose EFW was <10th percentile and had no velocimetry abnormalities.

RESULTS

The median fetal aIMT was significantly different in the three groups (Group A = 0.9 mm; Group B = 0.7 mm; and appropriate for gestational age (AGA) = 0.5 mm; p < .0001). It was significantly higher in Group A than in the AGA group (p < .0001) and than in the Group B fetuses (p = .003), respectively. In addition, ACR was different in the three groups (Group A = 183,500 mg/g; Group B = 6,4720 mg/g; and AGA = 8,2750 mg/g; p = .0002). It was significantly higher in Group A than in the AGA group (p = .03) and than in Group B (p = .02), respectively.

CONCLUSIONS

Growth-restricted twin fetuses with velocimetry abnormalities present are associated with aIMT and higher ACR levels in amniotic fluid, which could be possible markers in utero of preclinical atherosclerosis, and early glomerulosclerosis.

Developmental programming of cardiovascular risk in intrauterine growth-restricted twin fetuses according to aortic intima thickness

OBJECTIVES

We aimed to test the hypothesis that aortic intima thickness is greater in intrauterine growth-restricted (IUGR) twin fetuses compared to normally developing twins, thus defining an increased cardiovascular risk that reflects genetic factors in fetuses sharing the same womb.

METHODS

We conducted a prospective study performed on twins from January 2009 to July 2011. Twins were classified into 3 groups: IUGR fetuses with an estimated fetal weight below the 10th percentile and an umbilical artery pulsatility index of greater than 2 SDs (group A), fetuses with an estimated fetal weight below the 10th percentile and normal Doppler findings (group B), and fetuses with an estimated fetal weight appropriate for gestational age (group C). Aortic intima thickness was measured at a median gestational age of 32 weeks. Values were compared among groups and between each twin and cotwin, also considering sex and chorionicity.

RESULTS

Twenty-five fetuses were classified as group A, 36 as group B, and 95 as group C. The median aortic intima thickness values were 0.9 mm in group A, 0.7 mm in group B, and 0.6 mm in group C (P < .0001). There was a statistically significant difference between the aortic intima thickness of the twins and cotwins in groups A and B (P < .0001). Sex and chorionicity did not correlate with aortic intima thickness.

CONCLUSIONS

In this study, IUGR fetuses with Doppler abnormalities had greater aortic intima thickness, and IUGR twins with normal Doppler findings had intermediate thickness, supporting a genetic predisposition to cardiovascular risk independent of sex and chorionicity.

Fetal aortic wall thickness: a marker of hypertension in IUGR children?

Fetuses with intrauterine growth restriction (IUGR) have significant aortic intima-media thickening (aIMT), which suggests that preclinical atherosclerosis might predispose the infants to hypertension. However, the natural course of aIMT in babies with IUGR remains an open question.The study enrolled 77 pregnant women between January 2007 and August 2009. The fetuses were classified as AGA (appropriate for gestational age) or IUGR, if the estimated fetal weight was between the 10th and 90th percentile or below the 10th percentile (with umbilical artery pulsatility index (PI) >2s.d.), respectively. Anthropometric parameters and aIMT were detected in each IUGR and AGA fetus at a mean gestational age of 32 weeks. The follow-up was performed in 25 IUGR and 25 AGA infants at a mean postnatal age of 18 months; the previous measurements were repeated, and blood pressure measurements were taken. The maximum aIMT was significantly higher in the IUGR fetuses and infants compared with the AGA infants, both in utero (2.05±0.43 vs. 1.05±0.19 mm, P<0.001) and at the follow-up (2.3±0.8 vs. 1.06±0.18 mm, P<0.0001), the resulting values significantly correlated (P=0.018) with one another. The systolic blood pressure was significantly increased in the IUGR subjects (123±16 vs. 104±8.5 mm Hg, P<0.0004), and it correlated with the prenatal and postnatal aIMT values (P<0.0156 and P<0.0054, respectively). The aortic wall thickening progression in IUGR fetuses and infants differed from AGA, which may predispose the infants to hypertension early in life and cardiovascular risk later in life.

Relation of neutrophil to lymphocyte ratio with the presence and severity of stable coronary artery disease

OBJECTIVES

We examined the association between neutrophil to lymphocyte ratio (NLR) and the complexity of coronary artery disease assessed by SYNTAX score (SS).

METHODS

The study population included patients with chest pain who had undergone coronary angiography for stable angina pectoris. Patients were classified depending on whether the SS was 0 or SS > 0.

RESULTS

Left ventricular ejection fraction, estimated glomerular filtration rate, and NLR were found to be the independent predictors of high SS in multivariate analysis. The area under the receiver-operating curve of NLR was 0.72 (0.65-0.80, P < .001) for predicting high SS. The optimal cutoff value of NLR to predict high SS was 2.7 (sensitivity of 72% and a specificity of 61%). There was a significant correlation between NLR ratio and continuous SS (r = .552, P < .001).

CONCLUSION

The NLR is a readily measurable systemic inflammatory marker and is associated with both the presence and the complexity of coronary artery disease.

Early-life sex-dependent vulnerability to oxidative stress: the natural twining model

OBJECTIVES

Twins represent a unique natural model for studying fetal adaptation to a suboptimal supply of nutrients in utero, the most likely cause of reduced fetal growth, which has been associated with cardiovascular risk. The proposed developmental origin of cardiovascular diseases may offer new venues for investigating the molecular basis of the well-known gender disparity in cardiovascular disease pathogenesis and progression. Early sex differences in oxidative stress, a mechanism of injury associated with both reduced fetal growth and cardiovascular diseases, have been so far poorly investigated. Thus, we aimed at evaluating oxidative stress in newborn twins by measuring oxidative stress biomarkers in cord blood.

METHODS

Blood samples were collected from umbilical cord of 80 premature twins. The oxidative stress biomarker15-F(2t)-isoprostane and the total antioxidant capacity (tAOC) were measured in cord plasma.

RESULTS

Males had higher levels of plasma 15-F(2t)-isoprostane than females. 15-F(2t)-isoprostane values remained greater in males than in females when considering like-sex or unlike sex pairs. No difference was found in tAOC levels.

CONCLUSIONS

Our data suggest that sex-based differences in oxidant injury vulnerability occurring early in life could represent a biological mechanism contributing to gender disparity later in life.

Peripheral nerve blockade and neonatal limb ischemia: our experience and literature review

Considering the high frequency of bleeding complications following fibrinolytic treatment in neonates, peripheral nerve blockade (PNB) has been proposed alone or in association with lower doses of tissue plasminogen activator, as a possible new therapeutic approach in the management of neonatal limb ischemia (LI) secondary to vasospasm and/or thrombosis. The present article provides a review of the current knowledge about the topic, in order to evaluate the efficacy and safety of this therapeutic approach. According to the few case reports documented in literature and to our experience, PNB could be considered as valid procedure for the treatment of LI, especially during neonatal period, when the risk of serious bleeding associated with fibrinolytic or anticoagulant therapy is higher. Peripheral nerve blockade resulted in a safe and effective procedure for the treatment of neonatal vascular spasm and thrombosis.

Fetal cardiac muscle contractility decreases with gestational age: a color-coded tissue velocity imaging study

Background

Present data regarding how the fetal heart works and develops throughout gestation is limited. However, the possibility to analyze the myocardial velocity profile provides new possibilities to gain further knowledge in this area. Thus, the objective of this study was to evaluate human fetal myocardial characteristics and deformation properties using color-coded tissue velocity imaging (TVI).

Methods

TVI recordings from 55 healthy fetuses, at 18 to 42 weeks of gestation, were acquired at a frame rate of 201–273 frames/s for offline analysis using software enabling retrieval of the myocardial velocity curve and 2D anatomical information. The measurements were taken from an apical four-chamber view, and the acquired data was correlated using regression analysis.

Results

Left ventricular length and width increased uniformly with gestational age. Atrioventricular plane displacement and the E’/A’ ratio also increased with gestational age, while a longitudinal shortening was demonstrated.

Conclusions

Fetal cardiac muscle contractility decreases with gestational age. As numerous fetal- and pregnancy-associated conditions directly influence the pumping function of the fetal heart, we believe that this new insight into the physiology of the human fetal cardiovascular system could contribute to make diagnosis and risk assessment easier and more accurate.

Developmental programming of cardiovascular dysfunction by prenatal hypoxia and oxidative stress

Fetal hypoxia is a common complication of pregnancy. It has been shown to programme cardiac and endothelial dysfunction in the offspring in adult life. However, the mechanisms via which this occurs remain elusive, precluding the identification of potential therapy. Using an integrative approach at the isolated organ, cellular and molecular levels, we tested the hypothesis that oxidative stress in the fetal heart and vasculature underlies the molecular basis via which prenatal hypoxia programmes cardiovascular dysfunction in later life. In a longitudinal study, the effects of maternal treatment of hypoxic (13% O(2)) pregnancy with an antioxidant on the cardiovascular system of the offspring at the end of gestation and at adulthood were studied. On day 6 of pregnancy, rats (n = 20 per group) were exposed to normoxia or hypoxia ± vitamin C. At gestational day 20, tissues were collected from 1 male fetus per litter per group (n = 10). The remaining 10 litters per group were allowed to deliver. At 4 months, tissues from 1 male adult offspring per litter per group were either perfusion fixed, frozen, or dissected for isolated organ preparations. In the fetus, hypoxic pregnancy promoted aortic thickening with enhanced nitrotyrosine staining and an increase in cardiac HSP70 expression. By adulthood, offspring of hypoxic pregnancy had markedly impaired NO-dependent relaxation in femoral resistance arteries, and increased myocardial contractility with sympathetic dominance. Maternal vitamin C prevented these effects in fetal and adult offspring of hypoxic pregnancy. The data offer insight to mechanism and thereby possible targets for intervention against developmental origins of cardiac and peripheral vascular dysfunction in offspring of risky pregnancy.

Cord blood metabolomic profiling in intrauterine growth restriction

A number of metabolic abnormalities have been observed in pregnancies complicated by intrauterine growth restriction (IUGR). Metabolic fingerprinting and clinical metabolomics have recently been proposed as tools to investigate individual phenotypes beyond genomes and proteomes and to advance hypotheses on the genesis of diseases. Non-targeted metabolomic profiling was employed to study fetal and/or placental metabolism alterations in IUGR fetuses by liquid chromatography high-resolution mass spectrometry (LC-HRMS) analysis of cord blood collected soon after birth. Samples were collected from 22 IUGR and 21 appropriate for gestational age (AGA) fetuses. Birth weight differed significantly between IUGR and AGA fetuses (p < 0.001). Serum samples were immediately obtained and deproteinized by mixing with methanol at room temperature and centrifugation; supernatants were lyophilized and reconstituted in water for analysis. LC-HRMS analyses were performed on an Orbitrap mass spectrometer linked to a Surveyor Plus LC. Samples were injected into a 1.0 × 150-mm Luna C18 column. Spectra were collected in full-scan mode at a resolution of approximately 30,000. Data were acquired over the m/z range of 50-1,000, with measurements performed in duplicate. To observe metabolic variations between the two sets of samples, LC-HRMS data were analyzed by a principal component analysis model. Many features (e.g., ionic species with specific retention times) differed between the two classes of samples: among these, the essential amino acids phenylalanine, tryptophan, and methionine were identified by comparison with available databases. Logistic regression coupled to a receiver-operating characteristic curve identified a cut-off value for phenylalanine and tryptophan, which gave excellent discrimination between IUGR and AGA fetuses. Non-targeted LC-HRMS analysis of cord blood collected at birth allowed the identification of significant differences in relative abundances of essential amino acids between IUGR and AGA fetuses, emerging as a promising tool for studying metabolic alterations.

Morphological and functional alterations in the aorta of the chronically hypoxic fetal rat

In human pregnancy, reduced placental perfusion has been associated with fetal aortic thickening. However, the relative contributions of fetal undernutrition versus fetal underoxygenation to triggering alterations in fetal cardiovascular development remain uncertain. Here, we isolate the effects of chronic fetal hypoxia on fetal cardiovascular development in a specific rodent model of chronic fetal hypoxia independent of changes in nutrition during pregnancy. Pregnant rats were housed under normoxic (21% O(2)) or hypoxic (13% O(2)) conditions from day 6 to day 20 of gestation. At day 20, pups and placentas were weighed. Fetal thoraces were fixed for quantitative histological analysis of the aorta. In a separate group, fetal aortic reactivity was assessed via in vitro wire myography. The experiments controlled for sex and within-litter variation. Placental weight was increased and fetal weight maintained in hypoxic pregnancy. Hypoxic pregnancy led to a 176% increment in wall thickness and a 170% increment in the wall-to-lumen area ratio of the fetal aorta. Fetal aortic vascular reactivity was markedly impaired, showing reduced constrictor and relaxant responsiveness in hypoxic pregnancy. Chronic developmental hypoxia independent of changes in nutrition has profound effects on the morphology and function of the fetal aorta in a mammalian species.

Aortic intima-media thickness in nicotine-exposed rat pups during gestation and lactation period

There have been several studies confirming an association between maternal smoking during pregnancy and low birth weight. The detrimental effect of nicotine exposure beginning in fetal life continues during lactation, in infancy and in the early childhood period. In our previous studies, we found increased aortic intima-media thickness (aIMT) as a preatherosclerotic lesion in neonates with intrauterine growth restriction and in infants of smoking mothers. We aimed to evaluate histopathologically the effect of nicotine exposure during pregnancy and lactation period on fetal growth and aIMT at postnatal 45 days of age (end of the mid-adolescent period) in rat pups living in the same conditions. Gravid rats were assigned into three groups. In nicotine A, pregnant rats received 6 mg/kg/day nicotine intraperitoneally during pregnancy from 1 to 21 days of gestation and lactation (until postnatal day 21). Nicotine B received 3 mg/kg/day nicotine for the same period. Control pregnant rats received only saline intraperitoneally. Abdominal aIMT was studied histopathologically at postnatal 45 days of age. Nicotine exposure resulted in decreased birth weight and pregnancy weight gain. The mean aIMT values of the rat pups exposed to nicotine in both nicotine A and B groups were higher than those of the control group (103.78 ± 21.33 μm, 99.11 ± 30.12 μm, and 62.56 ± 7.18 μm, respectively). In conclusion, the detrimental effect on birth weight of nicotine exposure that began in fetal life is dose dependent. Nicotine exposure during intrauterine life and the lactation period causes increased aIMT in rat pups.

Fetal aorta wall inflammation in ultrasound-detected aortic intima/media thickness and growth retardation

Several studies have reported that fetuses with intrauterine growth restriction (IUGR) and infants with low birth weight present increased intima/media thickness (aIMT) of the abdominal aorta wall compared with fetuses and infants appropriate for gestational age (AGA). Evidence suggested that aIMT might be related to inflammation, probably indicating a very early stage of future adulthood disease, such as atherosclerosis. We aimed to investigate histological findings in the abdominal aorta wall of one IUGR stillbirth in which ultrasound had detected aIMT. Microscopy observations of the abdominal aorta wall confirmed the intima thickening and detected condensation of the elastic fibers forming an evident internal elastic membrane and presence of inflammatory elements, such as macrophages, activated endothelial cells, and fibroblastoid cells. The present study highlights that IUGR associated with aIMT is related to inflammation, which might represent a very early sign of future adult lesions.

Intrauterine growth restriction is associated with persistent aortic wall thickening and glomerular proteinuria during infancy

Low birth weight, caused either by preterm birth or by intrauterine growth restriction, has recently been associated with increased rates of adult renal and cardiovascular disease. Since aortic intima–media thickening is a noninvasive marker of preclinical vascular disease, we compared abdominal aortic intima–media thickness among intrauterine growth restricted and equivalent gestational age fetuses in utero and at 18 months of age. The relationship between intrauterine growth restriction, fetal aortic thickening, and glomerular function during infancy was measured by enrolling 44 mothers with single-fetus pregnancies at 32 weeks gestation: 23 growth restricted and 21 of appropriate gestational age as controls. Abdominal aortic intima–media thickness was measured by ultrasound at enrollment and again at 18 months of age. Fetuses with intrauterine growth restriction had significantly higher abdominal aortic intima–media thickness compared with age controls when measured both in utero and at 18 months. At 18 months, the median urinary microalbumin and median albumin–creatinine ratio were significantly higher in those infants who experienced intrauterine growth restriction compared to the controls. Our results show that intrauterine growth restriction is associated with persistent aortic wall thickening and significantly higher microalbuminuria during infancy.

The importance of venous Doppler velocimetry for evaluation of intrauterine growth restriction

The management of growth-restricted fetuses requires accurate diagnosis to optimize the timing of delivery. Doppler velocimetry is the only noninvasive method for assessing the fetoplacental hemodynamic status. This review will give a critical overview of the current knowledge on fetal venous blood flow in pregnancies complicated by in-trauterine growth-restricted fetuses. Adaptation of the circulation in intrauterine growth-restricted fetuses is described. Normal and abnormal venous Doppler waveforms are presented. Correlations of abnormal waveforms with the presence of acidemia and perinatal outcomes are emphasized. Limitations of venous Doppler velocimetry for optimizing the time for delivery and the perinatal outcome are also presented.

Flow-mediated vasodilation is impaired in adult rat offspring exposed to prenatal hypoxia

There is now a demonstrated association between low birth weight and increased mortality later in life. Changes in fetal development may program the cardiovascular system and lead to an increased risk of cardiovascular diseases later in life. In addition, aging is a risk factor for vascular endothelial-dependent dysfunction. However, the impact of being born intrauterine growth restricted (IUGR) on the normal aging mechanisms of vascular dysfunction is not clear. We hypothesized that IUGR would cause changes in vascular function that would affect the mechanisms of flow-induced vasodilation later in life in an age- or sex-dependent manner. To create an IUGR model, pregnant Sprague-Dawley rats were placed in a hypoxic (11.5% O2) or control (room air, 21% O2) environment from days 15 to 21 of pregnancy. Both male and female offspring were investigated at 4 or 12 mo of age. Vascular function was assessed in small mesenteric arteries using flow-induced vasodilation, a physiological stimuli of vasodilation, in a pressure myograph. Flow-induced vasodilation was unaffected at a young age, but was significantly reduced in aging IUGR compared with aging controls ( P < 0.05). Underlying vasodilator mechanisms were altered such that nitric oxide-mediated vasodilation was abolished in both young adult and aging IUGR males and females and in aging control females ( P > 0.05). Endothelium-derived hyperpolarizing factor-mediated vasodilation was maintained in all groups ( P < 0.01). A change in the mechanisms of vasodilation occurring at an earlier age in IUGR offspring may predispose them to develop cardiovascular diseases as an aging adult.

Consequences in infants that were intrauterine growth restricted

Intrauterine growth restriction is a condition fetus does not reach its growth potential and associated with perinatal mobility and mortality. Intrauterine growth restriction is caused by placental insufficiency, which determines cardiovascular abnormalities in the fetus. This condition, moreover, should prompt intensive antenatal surveillance of the fetus as well as follow-up of infants that had intrauterine growth restriction as short and long-term sequele should be considered.