Vascular aging and cardiac maladaptation in growth-restricted preterm infants

Molecular regulators of defective placental and cardiovascular development in fetal growth restriction

Placental insufficiency is one of the major causes of fetal growth restriction (FGR), a significant pregnancy disorder in which the fetus fails to achieve its full growth potential in utero. As well as the acute consequences of being born too small, affected offspring are at increased risk of cardiovascular disease, diabetes and other chronic diseases in later life. The placenta and heart develop concurrently, therefore placental maldevelopment and function in FGR may have profound effect on the growth and differentiation of many organ systems, including the heart. Hence, understanding the key molecular players that are synergistically linked in the development of the placenta and heart is critical. This review highlights the key growth factors, angiogenic molecules and transcription factors that are common causes of defective placental and cardiovascular development.

Understanding changes in echocardiographic parameters at different ages following fetal growth restriction: a systematic review and meta-analysis

Fetal growth restriction (FGR) increases cardiovascular risk by cardiac remodeling and programming. This systematic review and meta-analysis across species examines the use of echocardiography in FGR offspring at different ages. PubMed and Embase.com were searched for animal and human studies reporting on echocardiographic parameters in placental insufficiency-induced FGR offspring. We included six animal and 49 human studies. Although unable to perform a meta-analysis of animal studies because of insufficient number of studies per individual outcome, all studies showed left ventricular dysfunction. Our meta-analyses of human studies revealed a reduced left ventricular mass, interventricular septum thickness, mitral annular peak velocity, and mitral lateral early diastolic velocity at neonatal age. No echocardiographic differences during childhood were observed, although the small age range and number of studies limited these analyses. Only two studies at adult age were performed. Meta-regression on other influential factors was not possible due to underreporting. The few studies on myocardial strain analysis showed small changes in global longitudinal strain in FGR offspring. The quality of the human studies was considered low and the risk of bias in animal studies was mostly unclear. Echocardiography may offer a noninvasive tool to detect early signs of cardiovascular predisposition following FGR. Clinical implementation yet faces multiple challenges including identification of the most optimal timing and the exact relation to long-term cardiovascular function in which echocardiography alone might be limited to reflect a child's vascular status. Future research should focus on myocardial strain analysis and the combination of other (non)imaging techniques for an improved risk estimation.NEW & NOTEWORTHY Our meta-analysis revealed echocardiographic differences between fetal growth-restricted and control offspring in humans during the neonatal period: a reduced left ventricular mass and interventricular septum thickness, reduced mitral annular peak velocity, and mitral lateral early diastolic velocity. We were unable to pool echocardiographic parameters in animal studies and human adults because of an insufficient number of studies per individual outcome. The few studies on myocardial strain analysis showed small preclinical changes in FGR offspring.

Cardiovascular decline in offspring during the perinatal period in an ovine model of fetal growth restriction

Fetal growth restriction (FGR) increases the risk cardiovascular disease (CVD) in adulthood. Placental insufficiency and subsequent chronic fetal hypoxemia are causal factors for FGR, leading to a redistribution of blood flow that prioritizes vital organs. Subclinical signs of cardiovascular dysfunction are evident in growth-restricted neonates; however, the mechanisms programming for CVD in adulthood remain unknown. This study aimed to determine the potential mechanisms underlying structural and functional changes within the heart and essential (carotid) and nonessential (femoral) vascular beds in growth-restricted lambs. Placental insufficiency was surgically induced in ewes at 89 days gestational age (dGA, term = 148dGA). Three age groups were investigated: fetal (126dGA), newborn (24 h after preterm birth), and 4-wk-old lambs. In vivo and histological assessments of cardiovascular indices were undertaken. Resistance femoral artery function was assessed via in vitro wire myography and blockade of key vasoactive pathways including nitric oxide, prostanoids, and endothelium-dependent hyperpolarization. All lambs were normotensive throughout the first 4 wk of life. Overall, the FGR cohort had more globular hearts compared with controls (P = 0.0374). A progressive decline in endothelium-dependent vasodilation was demonstrated in FGR lambs compared with controls. Further investigation revealed that impairment of the prostanoid pathway may drive this reduction in vasodilatory capacity. Clinical indicators of CVD were not observed in our FGR lambs. However, subclinical signs of cardiovascular dysfunction were present in our FGR offspring. This study provides insight into potential mechanisms, such as the prostanoid pathway, that may warrant therapeutic interventions to improve cardiovascular development in growth-restricted newborns.NEW & NOTEWORTHY Our findings provide novel insight into the potential mechanisms that program for cardiovascular dysfunction in growth-restricted neonates as our growth-restricted lambs exhibited a progressive decline in endothelium-dependent vasodilation in the femoral artery between birth and 4 wk of age. Subsequent analyses indicated that this reduction in vasodilatory capacity is likely to be mediated by the prostanoid pathway and prostanoids could be a potential target for therapeutic interventions for fetal growth restriction (FGR).

Does fetal growth restriction induce neuropathology within the developing brainstem?

Fetal growth restriction (FGR) is a complex obstetric issue describing a fetus that does not reach its genetic growth potential. The primary cause of FGR is placental dysfunction resulting in chronic fetal hypoxaemia, which in turn causes altered neurological, cardiovascular and respiratory development, some of which may be pathophysiological, particularly for neonatal life. The brainstem is the critical site of cardiovascular, respiratory and autonomic control, but there is little information describing how chronic hypoxaemia and the resulting FGR may affect brainstem neurodevelopment. This review provides an overview of the brainstem-specific consequences of acute and chronic hypoxia, and what is known in FGR. In addition, we discuss how brainstem structural alterations may impair functional control of the cardiovascular and respiratory systems. Finally, we highlight the clinical and translational findings of the potential roles of the brainstem in maintaining cardiorespiratory adaptation in the transition from fetal to neonatal life under normal conditions and in response to the pathological environment that arises during development in growth-restricted infants. This review emphasises the crucial role that the brainstem plays in mediating cardiovascular and respiratory responses during fetal and neonatal life. We assess whether chronic fetal hypoxaemia might alter structure and function of the brainstem, but this also serves to highlight knowledge gaps regarding FGR and brainstem development.

Impact of perinatal factors on biomarkers of cardiovascular disease risk in preadolescent children

BACKGROUND

This review aims to summarize associations of the perinatal environment with arterial biophysical properties in childhood, to elucidate possible perinatal origins of adult cardiovascular disease (CVD).

METHODS

A systematic search of PubMed database was performed (December 2020). Studies exploring associations of perinatal factors with arterial biophysical properties in children 12 years old or less were included. Properties studied included: pulse wave velocity; arterial stiffness or distensibility; augmentation index; intima-media thickness of aorta (aIMT) or carotids; endothelial function (laser flow Doppler, flow-mediated dilatation). Two reviewers independently performed study selection and data extraction.

RESULTS

Fifty-two of 1084 identified records were included. Eleven studies explored associations with prematurity, 14 explored maternal factors during pregnancy, and 27 explored effects of low birth weight, small-for-gestational age and foetal growth restriction (LBW/SGA/FGR). aIMT was consistently higher in offspring affected by LBW/SGA/FGR in all six studies examining this variable. The cause of inconclusive or conflicting associations found with other arterial biophysical properties and perinatal factors may be multifactorial: in particular, measurements and analyses of related properties differed in technique, equipment, anatomical location, and covariates used.

CONCLUSION

aIMT was consistently higher in LBW/SGA/FGR offspring, which may relate to increased long-term CVD risk. Larger and longer term cohort studies may help to elucidate clinical significance, particularly in relation to established CVD risk factors. Experimental studies may help to understand whether lifestyle or medical interventions can reverse perinatal changes aIMT. The field could be advanced by validation and standardization of techniques assessing arterial structure and function in children.

COVID-19 and Placental Infection: Are Fetal Survivors at Risk of Long-Term Cardiovascular Complications?

As we enter the fourth year of the coronavirus disease 2019 (COVID-19) pandemic, it has become obvious that adult survivors of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are susceptible to numerous complications in various organ systems. SARS-CoV-2 placental infection is an unanticipated complication of COVID-19 during pregnancy. We hypothesize that fetal survivors of SARS-CoV-2 placentitis are susceptible to long-term cardiovascular complications.

Early Life Programming of Vascular Aging and Cardiometabolic Events: The McDonald Lecture 2022

The early life programming of adult health and disease (Developmental Origins of Adult Health and Disease; DOHaD) concept has attracted increased attention during recent years. In this review evidence is presented for epidemiological associations between early life factors (birth weight, prematurity) and cardiometabolic traits and risk of disease in adult life. Even if not all studies concur, the evidence in general is supporting such links. This could be due to either nature or nurture. There is evidence to state that genetic markers influencing birth weight could also be of importance for offspring hypertension or risk of coronary heart disease, this supporting the nature argument. On the other hand, several studies, both historical and experimental, have found that the change of maternal dietary intake or famine in pregnancy may cause permanent changes in offspring body composition as well as in hemodynamic regulation. Taken together, this also supports the strategy of preventive maternal and child health care, starting already during the preconception period, for lowering the risk of adult cardiometabolic disease in the affected offspring. Further studies are needed to better understand the mediating mechanisms, for example concerning arterial function, hemodynamic regulation, renal function, and neuroendocrine influences, related to the development of early vascular aging (EVA) and cardiovascular disease manifestations.

Early Life Determinants of Vascular Structure in Fetuses, Infants, Children, and Adolescents: A Systematic Review and Meta-Analysis

OBJECTIVE

To investigate the association between early life exposures during the first 1000 days (conception to age 24 months) and aortic intima-media thickness (aIMT), an early indicator of cardiovascular disease (CVD) risk, in youths.

STUDY DESIGN

The MEDLINE, Embase, Scopus, CINAHL, and Allied and Complementary Medicine databases were searched from inception to July 2021. Eligibility criteria included observational controlled studies in youths aged <20 years with risk factors/exposures during the first 1000 days and aIMT measurements (unadjusted mean ± SD). Outcome data were pooled using a random-effects meta-analysis. Meta-regression was used to investigate confounders.

RESULTS

A total of 8657 articles were identified, of which 34 were included in our meta-analysis. The age of participants ranged from 22.9 weeks gestation in utero to 10.9 years. In the meta-analysis (n = 1220 cases, n = 1997 controls), the following factors were associated with greater aIMT: small for gestational age (SGA) status (14 studies, mean difference, 0.082 mm; 95% CI, 0.051-0.112; P < .001; I² = 97%), intrauterine growth restriction (6 studies; mean difference, 0.198 mm, 95% CI, 0.088-0.309; P < .001; I² = 97%), preeclampsia (2 studies; mean difference, 0.038 mm; 95% CI, 0.024-0.051; P < .001; I² = 38%), and large for gestational age (LGA) status (3 studies; mean difference, 0.089 mm; 95% CI, 0.043-0.0136; P < .001; I² = 93%). In meta-regression, older age (P < .001), higher prevalence of maternal smoking (P = .04), and SGA (P < .001) were associated with greater difference in aIMT in preterm participants compared with controls. Limitations included the high heterogeneity present in most meta-analyses and the scope of our meta-regression.

CONCLUSIONS

Adverse early life exposures are associated with greater aIMT in youths, consistent with an increased risk for CVD later in life. Further research is needed to determine whether intervention and preventive strategies deliver clinical benefits to improve future cardiovascular health.

Fetal growth restriction and neonatal-pediatric lung diseases: Vascular mechanistic links and therapeutic directions

Bronchopulmonary dysplasia (BPD) is the most common respiratory sequela of prematurity, and infants born with fetal growth restriction (FGR) are disproportionately represented in BPD statistics, as factors which affect somatic growth may also affect pulmonary growth. Effects of in-utero hypoxia underlying FGR on lung parenchymal architecture predisposing to BPD are well documented, but the pulmonary vascular constructs are not well appreciated. Disruption of angiogenesis during critical periods of lung growth impairs alveolarization, contributing to BPD pathogenesis. Pulmonary artery thickness/stiffness has been noted in FGR in the initial postnatal weeks, and also in well-grown infants with established BPD. The lack of waveform cushioning by the major arteries exposes the pulmonary resistance vessels to higher pulsatile stress, thereby accelerating microvascular disease. Reactive oxygen species, increased sympathetic activity and endothelial dysfunction are common mediators in FGR and BPD; each putative targets for prevention and/or therapeutics using interleukin (IL)-1 receptor antagonist (IL-1Ra), melatonin or inhibition of renin-angiotensin-aldosterone system. While BPD is the archetypal respiratory disease of infancy, effects of FGR on pulmonary function are long-term, extending well into childhood. This narrative links FGR in very/extremely preterm infants with BPD through the vascular affliction as a mechanistic and potentially, therapeutic pathway. Our objectives were to depict the burden of disease for FGR and BPD amongst preterm infants, portray vascular involvement in the placenta in FGR and BPD cohorts, provide high resolution vascular ultrasound information in both cohorts with a view to address therapeutic relevance, and lastly, link this information with paediatric age-group lung diseases.

Current Strategies to Optimize Nutrition and Growth in Newborns and Infants with Congenital Heart Disease: A Narrative Review

(1) Objective: This review aims to identify the clinical and practical barriers to optimizing nutrition in newborn infants with congenital heart disease (CHD) and to describe updated evidence-based recommendations for clinical and nutritional management of these patients in a narrative review. (2) Research Methods and Procedures: We conducted a search of the relevant literature published from 2000 to December 2021. (3) Results: CHD patients undergo several nutritional challenges related to the underlying cardiac disease anomaly, the potential increased risk of NEC, and delayed enteral feeding, resulting in inadequate energy intake and sub-optimal growth, increased morbidity and mortality. (4) Conclusions: To optimize nutrition and growth in newborn infants with CHD, standardized protocols should be implemented. Regular nutritional and growth assessment with a multi-disciplinary team is essential. We propose a decisional algorithm that may represent a potentially useful tool to guide clinicians to optimize growth and nutrition.

The thrifty phenotype hypothesis: The association between ultrasound and Doppler studies in fetal growth restriction and the development of adult disease

Barker pioneered the idea that the epidemic of coronary heart disease in Western countries in the 20th century, which paradoxically coincided with improved standards of living and nutrition, has its origin in fetal life. Indeed, there is substantial evidence associating low birthweight because of fetal growth restriction with an increased risk of vascular disease in later adult life. These conclusions led to the second part of the Barker hypothesis, the thrifty phenotype, in which adaptation to undernutrition in fetal life leads to permanent metabolic and endocrine changes. Such changes are beneficial if the undernutrition persists after birth but may predispose the individual to obesity and impaired glucose tolerance if conditions improve. The hypothesis assumes that a poor nutrient supply during a critical period of in utero life may "program" a permanent structural or functional change in the fetus, thereby altering the distribution of cell types, gene expression, or both. The fetus, in response to placental undernutrition and to maintain sufficient vascular supply to the brain, decreases resistance to blood flow in the middle cerebral artery. Simultaneously, because of the limited blood supply to the fetus, the arterial redistribution process is accompanied by increased resistance to flow to other fetal vital organs, such as the heart, kidneys, liver, and pancreas. It may explain why individuals exposed to ischemic changes in utero develop dyslipidemia, lower nephron number, and impaired glucose tolerance, all factors contributing to metabolic syndrome later in life. Nevertheless, support for the hypotheses comes mainly from studies in rodents and retrospective epidemiologic studies. This review focused on ultrasound and Doppler studies of human fetal growth restriction in several fetal organs: the placenta, fetal circulation, brain, heart, kidneys, adrenal glands, liver, and pancreas. Support for the hypothesis was provided by animal studies involving conditions that create fetuses with growth restriction with effects on various fetal organs and by human studies that correlate impaired fetal circulation with the in utero development and function of fetal organs.

Cardiovascular and Cerebrovascular Implications of Growth Restriction: Mechanisms and Potential Treatments

Fetal growth restriction (FGR) is a common complication of pregnancy, resulting in a fetus that fails to reach its genetically determined growth potential. Whilst the fetal cardiovascular response to acute hypoxia is well established, the fetal defence to chronic hypoxia is not well understood due to experiment constraints. Growth restriction results primarily from reduced oxygen and nutrient supply to the developing fetus, resulting in chronic hypoxia. The fetus adapts to chronic hypoxia by redistributing cardiac output via brain sparing in an attempt to preserve function in the developing brain. This review highlights the impact of brain sparing on the developing fetal cardiovascular and cerebrovascular systems, as well as emerging long-term effects in offspring that were growth restricted at birth. Here, we explore the pathogenesis associated with brain sparing within the cerebrovascular system. An increased understanding of the mechanistic pathways will be critical to preventing neuropathological outcomes, including motor dysfunction such as cerebral palsy, or behaviour dysfunctions including autism and attention-deficit/hyperactivity disorder (ADHD).

Impact of Acute and Chronic Hypoxia-Ischemia on the Transitional Circulation

The transition from intrauterine life to extrauterine existence encompasses significant cardiorespiratory adaptations. These include rapid lung aeration and increase in pulmonary blood flow (PBF). Perinatal asphyxia and fetal growth restriction can severely hamper this transition. Hypoxia is the common denominator in these 2 disease states, with the former characterized by acute insult and the latter by utero-placental insufficiency and a chronic hypoxemic state. Both may manifest as hemodynamic instability. In this review, we emphasize the role of physiologic-based cord clamping in supplementing PBF during transition. The critical role of lung aeration in initiating pulmonary gas exchange and increasing PBF is discussed. Physiologic studies in animal models have enabled greater understanding of the mechanisms and effects of various therapies on transitional circulation. With data from sheep models, we elaborate instrumentation for monitoring of cardiovascular and pulmonary physiology and discuss the combined effect of chest compressions and adrenaline in improving transition at birth. Lastly, physiologic adaptation influencing management in human neonatal cohorts with respect to cardiac and vascular impairments in hypoxic-ischemic encephalopathy and growth restriction is discussed. Impairments in right ventricular function and vascular mechanics hold the key to prognostication and understanding of therapeutic rationale in these critically ill cohorts. The right ventricle and pulmonary circulation seem to be especially affected and may be explored as therapeutic targets. The role of comprehensive assessments using targeted neonatal echocardiography as a longitudinal, reliable, and easily accessible tool, enabling precision medicine facilitating physiologically appropriate treatment choices, is discussed.

An Overview of Vascular Dysfunction and Determinants: The Case of Children of African Ancestry

The balance between dilatory and constrictive factors is important as it keeps blood vessels in a homeostatic state. However, altered physiological processes as a result of obesity, hypertension, oxidative stress, and other cardiovascular risk factors may lead to vascular damage, causing an imbalance of vasoactive factors. Over time, the sustained imbalance of these vasoactive factors may lead to vascular dysfunction, which can be assessed by non-invasive methods, such as flow-mediated dilation, pulse wave velocity, flow-mediated slowing, retinal vessel analysis, peripheral vascular reactivity, and carotid intima-media thickness assessment. Although there is increasing prevalence of cardiovascular risk factors (obesity and hypertension) in children in sub-Saharan Africa, little is known about how this may affect vascular function. This review focuses on vasoactive factors implicated in vascular (dys)function, highlighting the determinants and consequences of vascular dysfunction. It further describes the non-invasive methods used for vascular (dys)function assessments and, last, describes the impact of cardiovascular risk factors on vascular dysfunction in children of African ancestry.

Neonatal Blood Pressure Standards: What Is "Normal"?

Blood pressure (BP) is routinely measured in newborn infants. Published BP nomograms demonstrate a rise in BP following delivery in healthy infants at all gestational ages (GA) and evidence that BP values are higher with increasing birth weight and GA. However, the complex physiology that occurs in newborn infants and range of BP values observed at all GA make it difficult to identify "normal" BP for a specific infant at a specific time under specific conditions. As such, complete hemodynamic assessment should include the physical examination, perinatal history, other vital signs, and laboratory values in addition to BP values.

Premature Vascular Aging in Guinea Pigs Affected by Fetal Growth Restriction

Cardiovascular risk associated with fetal growth restriction (FGR) could result from an early impaired vascular function. However, whether this effect results in premature vascular aging has not been addressed. We studied the ex vivo reactivity of carotid and femoral arteries in fetal (near term), adults (eight months-old) and aged (16 months-old) guinea pigs in normal (control) and FGR offspring. Additionally, an epigenetic marker of vascular aging (i.e., LINE-1 DNA methylation) was evaluated in human umbilical artery endothelial cells (HUAEC) from control and FGR subjects. Control guinea pig arteries showed an increased contractile response (KCl-induced) and a progressive impairment of NO-mediated relaxing responses as animals get older. FGR was associated with an initial preserved carotid artery reactivity as well as a later significant impairment in NO-mediated responses. Femoral arteries from FGR fetuses showed an increased contractility but a decreased relaxing response compared with control fetuses, and both responses were impaired in FGR-adults. Finally, FGR-HUAEC showed decreased LINE-1 DNA methylation compared with control-HUAEC. These data suggest that the aging of vascular function occurs by changes in NO-mediated responses, with limited alterations in contractile capacity. Further, these effects are accelerated and imposed at early stages of development in subjects exposed to a suboptimal intrauterine environment.

Fetal growth restriction is associated with an altered cardiopulmonary and cerebral hemodynamic response to surfactant therapy in preterm lambs

BACKGROUND

Efficacy of surfactant therapy in fetal growth restricted (FGR) preterm neonates is unknown.

METHODS

Twin-bearing ewes underwent surgery at 105 days gestation to induce FGR in one twin by single umbilical artery ligation. At 123-127 days, catheters and flow probes were implanted in pulmonary and carotid arteries to measure flow and pressure. Lambs were delivered, intubated and mechanically ventilated. At 10 min, surfactant (100 mg kg^-1) was administered. Ventilation, oxygenation, and hemodynamic responses were recorded for 1 h before euthanasia at 120 min. Lung tissue and bronchoalveolar lavage fluid was collected for analysis of surfactant protein mRNA and phosphatidylcholines (PCs).

RESULTS

FGR preterm lambs were 26% lighter than appropriate for gestational age (AGA) lambs and had baseline differences in lung mechanics and pulmonary blood flows. Surfactant therapy reduced ventilator and oxygen requirements and improved lung mechanics in both groups, although a more rapid improvement in compliance and tidal volume was observed in AGA lambs. Surfactant administration was associated with decreased mean pulmonary and carotid blood flow in FGR but not AGA lambs. No major differences in surfactant protein mRNA or PC levels were noted.

CONCLUSIONS

Surfactant therapy was associated with an altered pulmonary and cerebral hemodynamic response in preterm FGR lambs.

The relationship between serum vitamin D levels and intima-media thickness in term infants

Increasing epidemiologic evidence indicates that vitamin D deficiency is linked to a series of diseases, including cardiovascular disease. This prospective study was designed to determine the relationship between 25 hydroxyvitamin D (25(OH)D) level and aortic intima-media thickness (aIMT) and carotid intima-media thickness (cIMT) in term healthy neonates. A total of 135 term, healthy infants were included in the study. Ultrasonographic measurements were performed at 24-48 h after birth. Blood samples were obtained from the umbilical cord at birth. The neonates were divided into four groups according to serum 25(OH)D vitamin levels. For the entire cohort, the mean 25 hydroxyvitamin D level was found to be 15.17 ± 9.66 ng/mL. The mean values of cIMT and aIMT measurements were 0.386 ± 0.052 and 0.412 ± 0.076 mm, respectively. In group 4, mean and maximum aIMT measurements were significantly lower than the other groups (p = <0.001 and 0.001, respectively). We did not observe any significant difference between groups regarding cIMT measurements. Correlation was found between aIMT and 25 hydroxyvitamin D levels (r = 0.295 p = < 0.001).Conclusion: We conclude that vitamin D deficiency may be associated with early relative intima-media thickening of the aorta already in the first week of life. What is Known: • Vitamin D deficiency is linked to a series of diseases, including cardiovascular disease. • Studies in adults and high-risk children have shown that the measurement of the intima-media thickness represents an excellent marker of subclinical atherosclerosis. What is New: • This is the first study evaluating the relationship between 25(OH)D vitamin level and intima-media thickness in term healthy neonates. • Vitamin D deficiency in neonates may induce atherosclerosis early in life and the aortic intima-media thickness measurements may be used as an early marker for detection.

Placental histopathology in preterm fetal growth restriction

AIMS

Approximately 6-9% pregnancies are affected by fetal growth restriction (FGR). Placental alterations related to utero-placental insufficiency in FGR may induce placental vascular remodelling to the detriment of the fetus. The objective of this article was to study histopathological features of placentae in a cohort of preterm growth-restricted infants in comparison to a cohort of preterm appropriately grown infants.

METHODS

In a cohort of 40 preterm infants of 28-32 weeks' gestation, placental histopathology was evaluated by a histopathologist, who was blinded to the identity of the grouping. Twenty infants had FGR, while 20 were appropriate for gestational age (AGA). Predefined histopathological characteristics were assessed based on the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

The gestational age and birthweight of the FGR and AGA cohorts were 29.8 ± 1.3 versus 30 ± 0.9 weeks, P = 0.78 and 923 ± 168 versus 1403 ± 237 g, <0.001, respectively. Maternal vascular malperfusion, accelerated villous maturation and fetal vascular malperfusion were features that were significantly more common in FGR placentae.

CONCLUSION

Based on the results of the present study, specific placental histopathological changes may be present in FGR placentae, which may reflect the effects of utero-placental insufficiency.

Vascular changes in fetal growth restriction: clinical relevance and future therapeutics

Fetal growth restriction (FGR) affects about 5-10% pregnancies and is associated with poorer outcomes in the perinatal period. Additionally, long standing epidemiological data support its association with chronic diseases such as hypertension and diabetes. Cardiac and vascular adaptations in response to chronic hypoxemia due to utero-placental insufficiency are hallmarks of fetal adaptations. Investigators have attempted to identify these changes in the placenta at the microscopic and molecular level. The ex vivo dual perfusion model of the placenta enables the study of placental haemodynamics in growth-restricted pregnancies. Persistent arterial abnormalities (thickness and stiffness) noted on vascular ultrasound during fetal life through to the young-adult age group for those affected by FGR, seem to be a plausible link between in utero events and chronic circulatory diseases. Using these, this review reflects current thought on vascular maladaptive changes in the FGR cohorts and the role in investigating current and future therapeutics.

Neonatal Morbidities of Fetal Growth Restriction: Pathophysiology and Impact

Being born small lays the foundation for short-term and long-term implications for life. Intrauterine or fetal growth restriction describes the pregnancy complication of pathological reduced fetal growth, leading to significant perinatal mortality and morbidity, and subsequent long-term deficits. Placental insufficiency is the principal cause of FGR, which in turn underlies a chronic undersupply of oxygen and nutrients to the fetus. The neonatal morbidities associated with FGR depend on the timing of onset of placental dysfunction and growth restriction, its severity, and the gestation at birth of the infant. In this review, we explore the pathophysiological mechanisms involved in the development of major neonatal morbidities in FGR, and their impact on the health of the infant. Fetal cardiovascular adaptation and altered organ development during gestation are principal contributors to postnatal consequences of FGR. Clinical presentation, diagnostic tools and management strategies of neonatal morbidities are presented. We also present information on the current status of targeted therapies. A better understanding of neonatal morbidities associated with FGR will enable early neonatal detection, monitoring and management of potential adverse outcomes in the newborn period and beyond.

Somatic growth and the risks of bronchopulmonary dysplasia and pulmonary hypertension: connecting epidemiology and physiology 1

In the premature infant, poor growth in utero (fetal growth restriction) and in the first weeks of life (postnatal growth restriction) are associated with increased risk for bronchopulmonary dysplasia and pulmonary hypertension. In this review, we summarize the epidemiologic data supporting these associations, present a novel rodent model of postnatal growth restriction, and review 5 promising mechanisms by which poor nutrition may affect the developing lung. These observations support the hypothesis that nutritional and (or) pharmacologic interventions early in life may be able to decrease risk of the pulmonary complications of extreme prematurity.

Preterm growth restriction and bronchopulmonary dysplasia: the vascular hypothesis and related physiology

KEY POINTS

Approximately 5-10% pregnancies are affected by fetal growth restriction. Preterm infants affected by fetal growth restriction have a higher incidence of bronchopulmonary dysplasia. The present study is the first to measure pulmonary artery thickness and stiffness. The findings show that impaired vasculogenesis may be a contributory factor in the higher incidence of bronchopulmonary dysplasia in preterm growth restricted infants. The study addresses the mechanistic link between fetal programming and vascular architecture and mechanics.

ABSTRACT

Bronchopulmonary dysplasia is the most common respiratory sequelae of prematurity and histopathologically features fewer, dysmorphic pulmonary arteries. The present study aimed to characterize pulmonary artery mechanics and cardiac function in preterm infants with fetal growth restriction (FGR) compared to those appropriate for gestational age (AGA) in the early neonatal period. This prospective study reviewed 40 preterm infants between 28 to 32 weeks gestational age (GA). Twenty infants had a birthweight <10th centile and were compared with 20 preterm AGA infants. A single high resolution echocardiogram was performed to measure right pulmonary arterial and right ventricular (RV) indices. The GA and birthweight of FGR and AGA infants were 29.8 ± 1.3 vs. 30 ± 0.9 weeks (P = 0.78) and 923.4 g ± 168 vs. 1403 g ± 237 (P < 0.001), respectively. Assessments were made at 10.5 ± 1.3 days after birth. The FGR infants had significantly thicker right pulmonary artery inferior wall (843.5 ± 68 vs. 761 ± 40 μm, P < 0.001) with reduced pulsatility (51.6 ± 7.6 μm vs. 59.7 ± 7.5 μm, P = 0.001). The RV contractility [fractional area change (28.7 ± 3.8% vs 32.5 ± 3.1%, P = 0.001), tricuspid annular peak systolic excursion (TAPSE) (5.2 ± 0.3% vs. 5.9 ± 0.7%, P = 0.0002) and myocardial performance index (0.35 ± 0.03 vs. 0.28 ± 0.02, P < 0.001)] was significantly impaired in FGR infants. Significant correlation between RV longitudinal contractility (TAPSE) and time to peak velocity/RV ejection time (measure of RV afterload) was noted (r²  =  0.5, P < 0.001). Altered pulmonary vascular mechanics and cardiac performance reflect maladaptive changes in response to utero-placental insufficiency. Whether managing pulmonary vascular disease will alter clinical outcomes remains to be studied prospectively.