Preterm birth and risk of chronic kidney disease from childhood into mid-adulthood: national cohort study

Prevention of cardiorenal damage: importance of albuminuria

Chronic kidney disease (CKD) is projected to become a leading global cause of death by 2040, and its early detection is critical for effective and timely management. The current definition of CKD identifies only advanced stages, when kidney injury has already destroyed >50% of functioning kidney mass as reflected by an estimated glomerular filtration rate <60 mL/min/1.73 m2 or a urinary albumin/creatinine ratio >six-fold higher than physiological levels (i.e. > 30 mg/g). An elevated urinary albumin-excretion rate is a known early predictor of future cardiovascular events. There is thus a ‘blind spot’ in the detection of CKD, when kidney injury is present but is undetectable by current diagnostic criteria, and no intervention is made before renal and cardiovascular damage occurs. The present review discusses the CKD ‘blind spot’ concept and how it may facilitate a holistic approach to CKD and cardiovascular disease prevention and implement the call for albuminuria screening implicit in current guidelines. Cardiorenal risk associated with albuminuria in the high-normal range, novel genetic and biochemical markers of elevated cardiorenal risk, and the role of heart and kidney protective drugs evaluated in recent clinical trials are also discussed. As albuminuria is a major risk factor for cardiovascular and renal disease, starting from levels not yet considered in the definition of CKD, the implementation of opportunistic or systematic albuminuria screening and therapy, possibly complemented with novel early biomarkers, has the potential to improve cardiorenal outcomes and mitigate the dismal 2040 projections for CKD and related cardiovascular burden.

Renal oxygenation measured by near-infrared spectroscopy in preterm neonates in the first week

OBJECTIVE

To describe renal regional saturation of oxygen (RrSO₂) values during the first week of life for preterm neonates born at <32 weeks gestational age (GA).

METHODS

RrSO₂ values recorded over the first week of life using near-infrared spectroscopy were retrospectively analyzed in this two-center cohort study of preterm infants without known congenital anomalies of the kidney.

RESULTS

A cohort of 109 neonates with a median GA of 26.9 weeks and a median of 120 (IQR: 87-141) hours of continuous RrSO₂ monitoring were included. Separately fitted trends in RrSO₂ did not differ (p = 0.52) between sites and demonstrated a consistent decrease in RrSO₂ by 20 points (95% CI: 9.6-30.1) during the first 60 h of life, followed by a stabilization of RrSO₂ thereafter. RrSO₂ baseline trends increased by 2.1 (95% CI: 0.8-3.3) percentage points for each additional week GA between 24 and 32 weeks GA.

CONCLUSIONS

Despite differences in adjusted RrSO₂ values between sites, profiles over time are consistent, allowing for the determination of RrSO₂ trajectories in preterm infants. This expected pattern of RrSO₂ changes in the first week may help guide future investigations and interventions to identify and reduce kidney injury in the preterm neonate.

IMPACT

Renal regional saturation of oxygen (RrSO₂) slowly decreases during the first 60 h of age in <32-week preterm neonates. While site differences were identified with respect to absolute values, RrSO₂ trends from two different centers were not different. Lower gestational age neonates have lower RrSO₂ levels during the first week.

Low birth weight, nephron number and chronic kidney disease

Chronic kidney diseases have a significant impact on morbidity and mortality worldwide. Low birth weight, fetal growth restriction and prematurity are indicators of fetal growth and development disorders associated with a congenital reduction in nephron number, which predisposes to an increased risk for chronic kidney disease. On an individual basis, a small nephron number at birth is not always enough to determine the onset of chronic kidney disease, but it decreases the ability of the kidneys to resist any insults to renal tissue that may occur later in life, such as exposure to nephrotoxic drugs or episodes of acute kidney injury. The high incidence of low birth weight and preterm birth globally suggests that, at the population level, the impact of alterations in fetal development on the subsequent onset of chronic kidney disease could be significant. The implementation of strategies aimed at reducing the incidence of prematurity, fetal growth restriction, as well as other conditions that lead to low birth weight and a reduced nephron number at birth, provides an opportunity to prevent the development of chronic kidney disease in adulthood. For these purposes the coordinated intervention of several specialists, including obstetricians, gynecologists, neonatologists, nephrologists, and family doctors, is necessary. Such strategies can be particularly useful in resource-poor countries, which are simultaneously burdened by maternal, fetal and child malnutrition; poor health; epidemics caused by communicable diseases; and little access to screening and primary care.

Fetal growth restriction followed by very preterm birth is associated with smaller kidneys but preserved kidney function in adolescence

BACKGROUND

Preterm birth and fetal growth restriction (FGR) are associated with structural and functional kidney changes, increasing long-term risk for chronic kidney disease and hypertension. However, recent studies in preterm children are conflicting, indicating structural changes but normal kidney function. This study therefore assessed kidney structure and function in a cohort of adolescents born very preterm with and without verified FGR.

METHODS

Adolescents born very preterm with FGR and two groups with appropriate birthweight (AGA) were included; one matched for gestational week at birth and one born at term. Cortical and medullary kidney volumes and T1 and T2* mapping values were assessed by magnetic resonance imaging. Biochemical markers of kidney function and renin-angiotensin-aldosterone system (RAAS) activation were analyzed.

RESULTS

Sixty-four adolescents were included (13-16 years; 48% girls). Very preterm birth with FGR showed smaller total (66 vs. 75 ml/m²; p = 0.01) and medullary volume (19 vs. 24 ml/m²; p < 0.0001) compared to term AGA. Corticomedullary volume ratio decreased from preterm FGR (2.4) to preterm AGA (2.2) to term AGA (1.9; p = 0.004). There were no differences in T1 or T2* values (all p ≥ 0.34) or in biochemical markers (all p ≥ 0.12) between groups.

CONCLUSIONS

FGR with abnormal fetal blood flow followed by very preterm birth is associated with smaller total kidney and medullary kidney volumes, but not with markers of kidney dysfunction or RAAS activation in adolescence. Decreased total kidney and medullary volumes may still precede a long-term decrease in kidney function, and potentially be used as a prognostic marker. A higher resolution version of the Graphical abstract is available as Supplementary information.

Reporting and risk of bias of prediction models based on machine learning methods in preterm birth: A systematic review

INTRODUCTION

There was limited evidence on the quality of reporting and methodological quality of prediction models using machine learning methods in preterm birth. This systematic review aimed to assess the reporting quality and risk of bias of a machine learning-based prediction model in preterm birth.

MATERIAL AND METHODS

We conducted a systematic review, searching the PubMed, Embase, the Cochrane Library, China National Knowledge Infrastructure, China Biology Medicine disk, VIP Database, and WanFang Data from inception to September 27, 2021. Studies that developed (validated) a prediction model using machine learning methods in preterm birth were included. We used the Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis (TRIPOD) statement and Prediction model Risk of Bias Assessment Tool (PROBAST) to evaluate the reporting quality and the risk of bias of included studies, respectively. Findings were summarized using descriptive statistics and visual plots. The protocol was registered in PROSPERO (no. CRD 42022301623).

RESULTS

Twenty-nine studies met the inclusion criteria, with 24 development-only studies and 5 development-with-validation studies. Overall, TRIPOD adherence per study ranged from 17% to 79%, with a median adherence of 49%. The reporting of title, abstract, blinding of predictors, sample size justification, explanation of model, and model performance were mostly poor, with TRIPOD adherence ranging from 4% to 17%. For all included studies, 79% had a high overall risk of bias, and 21% had an unclear overall risk of bias. The analysis domain was most commonly rated as high risk of bias in included studies, mainly as a result of small effective sample size, selection of predictors based on univariable analysis, and lack of calibration evaluation.

CONCLUSIONS

Reporting and methodological quality of machine learning-based prediction models in preterm birth were poor. It is urgent to improve the design, conduct, and reporting of such studies to boost the application of machine learning-based prediction models in preterm birth in clinical practice.

Regulation of nephron progenitor cell lifespan and nephron endowment

Low nephron number - resulting, for example, from prematurity or developmental anomalies - is a risk factor for the development of hypertension, chronic kidney disease and kidney failure. Considerable interest therefore exists in the mechanisms that regulate nephron endowment and contribute to the premature cessation of nephrogenesis following preterm birth. The cessation of nephrogenesis in utero or shortly after birth is synchronized across multiple niches in all mammals, and is coupled with the exhaustion of nephron progenitor cells. Consequently, no nephrons are formed after the cessation of developmental nephrogenesis, and lifelong renal function therefore depends on the complement of nephrons generated during gestation. In humans, a tenfold variation in nephron endowment between individuals contributes to differences in susceptibility to kidney disease; however, the mechanisms underlying this variation are not yet clear. Salient advances in our understanding of environmental inputs, and of intrinsic molecular mechanisms that contribute to the regulation of cessation timing or nephron progenitor cell exhaustion, have the potential to inform interventions to enhance nephron endowment and improve lifelong kidney health for susceptible individuals.

Terminological relationships between nursing diagnoses for children with kidney diseases

OBJECTIVE

To identify the relationships between the statements of nursing diagnoses for children with kidney diseases prepared according to the International Classification for Nursing Practice (ICNP®) with the diagnoses of NANDA International (NANDA-I).

METHODS

Methodological study operationalized by the steps: 1) Survey of clinical findings through interviews and physical examination with children; 2) Elaboration of nursing diagnoses through Gordon's clinical judgment; 3) Cross-mapping of diagnostic statements between the NANDA-I and ICNP® classification systems; 4) Content validation using the Delphi technique, in two rounds, with specialist nurses.

RESULTS

90 children participated. A total of 151 diagnoses were made, of which 66.3% (n=100) used ICNP® terminology and 33.7% (n=51) used NANDA-I; 55 diagnoses showed equivalence of meanings.

CONCLUSIONS

Cross-mapping of diagnoses was achieved starting from the reality of children, using clinical reasoning and validation by specialist nurses.

Prevalence and Risk Factors for Kidney Disease and Elevated BP in 2-Year-Old Children Born Extremely Premature

BACKGROUND AND OBJECTIVES

Extremely low gestational age neonates born <28 weeks gestation are at risk for chronic disease. We sought to describe the prevalence of kidney outcomes by gestational age and determine risk factors for their development.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Recombinant Erythropoietin for Protection of Infant Renal Disease (REPAIReD) study examined kidney outcomes of extremely low gestational age neonates enrolled in the Preterm Epo NeuroProtection Trial (PENUT) study. Kidney function, urine albumin, and BP were measured at 2-year (24±2 months) corrected gestational age. We compared outcomes across gestational age categories and evaluated associations between kidney-related outcomes and neonatal and maternal characteristics. The primary outcome was eGFR <90 ml/min per 1.73 m² (CKD); secondary outcomes were spot urine albumin-creatinine ratio ≥30 mg/g (albuminuria) and either systolic BP or diastolic BP >90th percentile for height, age, and sex.

RESULTS

A total of 832 survived to 2 years, and 565 (68%) had at least one outcome measured. Overall, 297 (53%) had one abnormal kidney outcome; 61 (18%) had an eGFR <90 ml/min per 1.73 m², 155 (36%) had albuminuria, 65 (22%) had elevated systolic BP, and 128 (44%) had elevated diastolic BP. Gestational age (odds ratio, 0.94; 95% confidence interval, 0.89 to 0.99), birth weight z-score (odds ratio, 0.92; 95% confidence interval, 0.85 to 0.98), and prenatal steroids (odds ratio, 1.23; 95% confidence interval, 1.08 to 1.39) were associated with an eGFR <90 ml/min per 1.73 m². An elevated systolic BP was associated with indomethacin use (odds ratio, 1.18; 95% confidence interval, 1.04 to 1.33) and Black race (odds ratio, 1.19; 95% confidence interval, 1.01 to 1.39); elevated diastolic BP was associated with male sex (odds ratio, 1.29; 95% confidence interval, 1.12 to 1.49), severe AKI (odds ratio, 1.24; 95% confidence interval, 1.04 to 1.48), and indomethacin use (odds ratio, 1.16; 95% confidence interval, 1.01 to 1.33).

CONCLUSIONS

Approximately 18% of extremely low gestational age neonates have CKD, 36% have albuminuria, 22% have an elevated systolic BP, and 44% have an elevated diastolic BP at 2 years of age. Gestational age, birthweight z-score, and prenatal steroids were associated with CKD. Male sex, Black race, indomethacin use, and severe AKI were associated with elevated BP.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2022_07_19_CJN15011121.mp3.

What a paediatric nephrologist should know about preeclampsia and why it matters

Preeclampsia is a protean syndrome causing a kidney disease characterised by hypertension and proteinuria, usually considered transitory and reversible after delivery. Its prevalence ranges from 3-5 to 10% if all the related disorders are considered. This narrative review, on behalf of the Kidney and Pregnancy Study Group of the Italian Society of Nephrology, focuses on three reasons why preeclampsia should concern paediatric nephrologists and how they can play an important role in its prevention, as well as in the prevention of future kidney and cardiovascular diseases. Firstly, all diseases of the kidney and urinary tract diagnosed in paediatric age are associated with a higher risk of adverse pregnancy-related outcomes, including preeclampsia. Secondly, babies with low birth weights (small for gestational age, born preterm, or both) have an increased risk of developing the full panoply of metabolic diseases (obesity, hypertension, early-onset cardiopathy and chronic kidney disease) and girls are at higher risk of developing preeclampsia when pregnant. The risk may be particularly high in cases of maternal preeclampsia, highlighting a familial aggregation of this condition. Thirdly, pregnant teenagers have a higher risk of developing preeclampsia and the hypertensive disorders of pregnancy, and should be followed up as high risk pregnancies. In summary, preeclampsia has come to be seen as a window on the future health of both mother and baby. Identification of subjects at risk, early counselling and careful follow-up can contribute to reducing the high morbidity linked with this disorder.

Kidney Injuries and Evolution of Chronic Kidney Diseases Due to Neonatal Hyperoxia Exposure Based on Animal Studies

Preterm birth interrupts the development and maturation of the kidneys during the critical growth period. The kidneys can also exhibit structural defects and functional impairment due to hyperoxia, as demonstrated by various animal studies. Furthermore, hyperoxia during nephrogenesis impairs renal tubular development and induces glomerular and tubular injuries, which manifest as renal corpuscle enlargement, renal tubular necrosis, interstitial inflammation, and kidney fibrosis. Preterm birth along with hyperoxia exposure induces a pathological predisposition to chronic kidney disease. Hyperoxia-induced kidney injuries are influenced by several molecular factors, including hypoxia-inducible factor-1α and interleukin-6/Smad2/transforming growth factor-β, and Wnt/β-catenin signaling pathways; these are key to cell proliferation, tissue inflammation, and cell membrane repair. Hyperoxia-induced oxidative stress is characterized by the attenuation or the induction of multiple molecular factors associated with kidney damage. This review focuses on the molecular pathways involved in the pathogenesis of hyperoxia-induced kidney injuries to establish a framework for potential interventions.

Preterm Birth, Kidney Function and Cardiovascular Disease in Children and Adolescents

Over recent decades, there has been a global increase in preterm birth rate, which constitutes about 11% of total births worldwide. The present review aims to summarize the current knowledge on the long-term consequences of prematurity on renal and cardiovascular development and function. Recent literature supports that prematurity, intrauterine growth restriction or low birth weight (LBW) may have an adverse impact on the development of multiple organ systems, predisposing to chronic diseases in childhood and adulthood, such as arterial hypertension and chronic kidney disease. According to human autopsy and epidemiological studies, children born preterm have a lower nephron number, decreased kidney size and, in some cases, affected renal function. The origin of hypertension in children and adults born preterm seems to be multifactorial as a result of alterations in renal, cardiac and vascular development and function. The majority of the studies report increased systolic and diastolic blood pressure (BP) in individuals born preterm compared to full term. The early prevention and detection of chronic non-communicable diseases, which start from childhood and track until adulthood in children with a history of prematurity or LBW, are important.

Gestational age-specific serum creatinine can predict adverse pregnancy outcomes

Serum creatinine level (SCr) typically decreases during pregnancy due to physiologic glomerular hyperfiltration. Therefore, the clinical practice of estimated glomerular filtration rate (eGFR) based on SCr concentrations might be inapplicable to pregnant women with kidney disease since it does not take into account of the pregnancy-related biological changes. We integrated the Wonju Severance Christian Hospital (WSCH)-based findings and prior knowledge from big data to reveal the relationship between the abnormal but hidden SCr level and adverse pregnancy outcomes. We analyzed 4004 pregnant women who visited in WSCH. Adverse pregnancy outcomes included preterm birth, preeclampsia, fetal growth retardation, and intrauterine fetal demise. We categorized the pregnant women into four groups based on the gestational age (GA)-unadjusted raw distribution (Q1–4_raw), and then GA-specific (Q1–4_adj) SCr distribution. Linear regression analysis revealed that Q1-4_adj groups had better predictive outcomes than the Q1–4_raw groups. In logistic regression model, the Q1–4_adj groups exhibited a robust non-linear U-shaped relationship with the risk of adverse pregnancy outcomes, compared to the Q1–4_raw groups. The integrative analysis on SCr with respect to GA-specific distribution could be used to screen out pregnant women with a normal SCr coupled with a decreased renal function.

When the progresses in neonatology lead to severe congenital nephron deficit: is there a pilot in the NICU?

Advances in the care of neonates to the extreme limits of viability have increased the risk of severe comorbidities in surviving preemies. The respiratory and the neurodevelopmental consequences of premature birth and/or intra-uterine growth retardation have been well described. Because of the usual clinical silence of the kidney, the long-term renal consequences of low birth weight have not been as well studied. A case report illustrates the risk factors associated with low birth weight and prematurity and discusses the pathogenesis of the late consequences of the congenital nephron deficit associated with a low birth weight. Practical recommendations are given for a tight follow-up of these newly born preemies.

Neurodevelopmental disorders and somatic diagnoses in a national cohort of children born before 24 weeks of gestation

AIM

This study investigated childhood diagnoses in children born extremely preterm before 24 weeks of gestation.

METHODS

Diagnoses of neurodevelopmental disorders and selected somatic diagnoses were retrospectively retrieved from national Swedish registries for children born before 24 weeks from 2007 to 2018. Their individual medical files were also examined.

RESULTS

We studied 383 children born at a median of 23.3 (range 21.9-23.9) weeks, with a median birthweight of 565 (range 340-874) grams. Three-quarters (75%) had neurodevelopmental disorders, including speech disorders (52%), intellectual disabilities (40%), attention deficit hyperactivity disorder (30%), autism spectrum disorders (24%), visual impairment (22%), cerebral palsy (17%), epilepsy (10%) and hearing impairment (5%). More boys than girls born at 23 weeks had intellectual disabilities (45% vs. 27%, p < 0.01) and visual impairment (25% vs. 14%, p < 0.01). Just over half of the cohort (55%) received habilitation care. The majority (88%) had somatic diagnoses, including asthma (63%) and failure to thrive/short stature (39%).

CONCLUSION

Most children born before 24 weeks had neurodevelopmental disorders and/or additional somatic diagnoses in childhood and were referred to habilitation services. Clinicians should be aware of the multiple health and developmental problems affecting these children. Resources are needed to identify their long-term support needs at an early stage.

Impact of nephrotoxic drugs on urinary biomarkers of renal function in very preterm infants

BACKGROUND

Following preterm birth, the immature kidney is exposed to several harmful conditions, with an increased risk of renal impairment. We aimed to assess urinary biomarkers of renal function in very preterm infants during early nephrotoxic treatments.

METHODS

Infants ≤32 weeks' gestation and ≤1500 g were enrolled in this observational prospective study. Urine samples were collected on day 1(T1), 2-4(T2), 5-7(T3), 8-10(T4), 11-13(T5). The following urinary biomarkers were determined: osteopontin (uOPN), epidermal growth factor (uEGF), neutrophil gelatinase-associated lipocalin (uNGAL), cystatin C (uCysC). The infants were grouped according to their exposure to amikacin or ibuprofen during the study period and a between-group comparison of urinary biomarkers at each time point was performed.

RESULTS

Thirty-six infants were included. Urinary CysC, uOPN, and uNGAL rose significantly during ibuprofen or amikacin treatment, while no difference was observed for uEGF. After adjustment for possible influencing factors, amikacin administration was associated with higher uCysC at T1 (p = 0.007) and T2 (p = 0.016), whereas ibuprofen increased uOPN (p = 0.001) and uNGAL concentration (p = 0.009) at T3.

CONCLUSION

Nephrotoxic therapies induce molecule-specific change patterns of renal function biomarkers in treated preterm infants. Serial assessments of these biomarkers may aid to identify neonates at risk of renal impairment and to develop tailored therapeutic approaches.

IMPACT

Despite the wide use of nephrotoxic therapies in neonatal settings, little is known on their effect on renal function biomarkers in preterm infants. This study describes molecule-specific change patterns of urinary biomarkers during ibuprofen and amikacin administration, suggesting underlying pathophysiological effects on renal function. Given their low analytical costs and non-invasive collection, the urinary biomarkers investigated in this study represent a promising strategy for serial monitoring of renal function in at-risk neonates and may aid the early detection of renal function impairment at different kidney levels during nephrotoxic treatments.

Renal volume of five-year-old preterm children are not different than full-term controls

OBJECTIVE

In previous studies, smaller renal volumes were reported in prematurely born infants, however, these renal volumes were not corrected for body surface area, the main determinant of renal size. Given the rapid growth of the renal cortex after premature birth, the authors hypothesized that corrected volumes would not differ from healthy controls.

METHODS

Ambispective cohort study with prospective follow-up of prematurely born babies in a large specialized center and retrospectively recruited healthy control group. Children were assessed for renal length and renal volumes at age 5 by three independent ultrasonographers. Detailed anthropometry, blood pressure and renal function were also obtained. Age independent z-scores were calculated for all parameters and compared using descriptive statistics.

RESULTS

Eighty-nine premature study participants (median 32 weeks gestational age) and 33 healthy controls (median 38 weeks gestational age) were studied. Study participants did not differ in age, sex, Afro-Colombian descent, height, blood pressure, serum creatinine, or new Schwartz eGFR. Premature study participants had a significantly lower weight (17.65 ± 2.93 kg) than controls (19.05 ± 2.81 kg, p = 0.0072) and lower body surface area. The right renal volumes were significantly smaller (39.4 vs 43.4 mL), but after correction for body surface area, the renal volume and renal length z-scores were identical for both kidneys (mean right kidney -0.707 vs -0.507; mean left kidney -0.498 vs -0.524, respectively).

CONCLUSION

Renal volumes need to be corrected to body surface area. After correction for body surface area, 5-year-old healthy and prematurely born children have comparable renal volumes.

Effects of Prematurity and Growth Restriction on Adult Blood Pressure and Kidney Volume

Gaining insight into the complex cycle of renal programming and its early-life clinical associations is essential to understand the origins of kidney disease. Prematurity and intrauterine growth restriction are associated with low nephron endowment. This increases the risk of developing hypertension and chronic kidney disease later in life. There is appreciable evidence to support mechanistic links between low nephron endowment secondary to intrauterine events and kidney size, kidney function, and blood pressure in postnatal life. A clear understanding of the cycle of developmental programming and consequences of fetal insults on the kidney is critical. In addition, the impact of events in the early postnatal period (accelerated postnatal growth, development of obesity, exposure to nephrotoxins) on the cardiovascular system and blood pressure of individuals born prematurely or with low birth weight is discussed. In summary, this review draws attention to the concepts of renal programming and nephron endowment and underscores the associations between intrauterine growth restriction, prematurity, and its clinical consequences in adult life.

Under-Recognition of Neonatal Acute Kidney Injury and Lack of Follow-Up

OBJECTIVE

Acute kidney injury (AKI) incidence is 30% in neonatal intensive care units (NICU). AKI is associated with increased mortality and risk of chronic kidney disease (CKD) in children. To assess follow-up and early CKD, we retrospectively reviewed outcomes of Cincinnati Children's Hospital Medical Center (CCHMC) cohort of neonates from the AWAKEN trial (2014).

STUDY DESIGN

Data from 81 CCHMC patients were extracted from the AWAKEN dataset. KDIGO (Kidney Disease: Improving Global Outcomes) criteria for serum creatinine (SCr) and urine output (UOP) <1 mL/kg/h, reported per 24 hours on postnatal days 2 to 7, were used to define AKI. Charts were reviewed until May 2019 for death, nephrology consult, AKI diagnosis on discharge summary, follow-up, and early CKD at >6 months of age (defined as: estimated glomerular filtration rate < 90 mL/min/1.73 m², hyperfiltration, proteinuria, hypertension, or abnormal ultrasound). Patients were considered to have renal follow-up if they had ≥1 follow-up visit containing: SCr, urinalysis, or blood pressure measurement.

RESULTS

Seventy-seven patients had sufficient data to ascertain AKI diagnosis. In total 47 of 77 (61%) were AKI+ by SCr or UOP criteria (20 stage 1, 14 stage 2, 13 stage 3). Four died during their admission and five were removed from CKD analyses due to urologic anomalies. AKI-UOP alone outnumbered AKI-SCr (45 AKI+ vs 5 AKI+ for all stages). 33% of patients had <2 SCr measured while inpatient. Only 3 of 47 AKI+ patients had a nephrology consult (all stage 3 by SCr) and 2 of 47 had AKI included in discharge summary. 67% of AKI+ patients had follow-up. In total 10 of 43 (23%) AKI+ versus 12 of 25 (48%) AKI- patients had ≥1 marker of early CKD assessed after 6 months. Based on SCr, 3 of 7 (43%) AKI+ had hyperfiltration versus 0 of 7 (0%) AKI- (p = 0.19).

CONCLUSION

AKI is vastly under-recognized in the NICU, especially if based on SCr alone. This leads to insufficient follow-up to ascertain renal sequelae in this high-risk population.

KEY POINTS

· AKI is under-recognized in high-risk neonates.. · There is a lack of adequate follow-up.. · Identification of AKI by SCr alone is insufficient..

Global and Regional White Matter Fractional Anisotropy in Children with Chronic Kidney Disease

OBJECTIVE

To investigate the associations between neurocognition and white matter integrity in children with chronic kidney disease (CKD).

STUDY DESIGN

This cross-sectional study included 17 boys (age 6-16 years) with a diagnosis of mild to moderate (stages 1-3, nondialysis/nontransplant) CKD because of congenital anomalies of the kidney and urinary tract and 20 typically developing community controls. Participants underwent 3T neuroimaging and diffusion-weighted magnetic resonance imaging to assess white matter fractional anisotropy. Multivariable linear regression models were used to evaluate the impact of each group (controls vs CKD) on white matter fractional anisotropy, adjusting for age. Associations between white matter fractional anisotropy and neurocognitive abilities within the CKD group were also evaluated using regression models that were adjusted for age. The false discovery rate was used to account for multiple comparisons; wherein false discovery values <0.10 were considered significant.

RESULTS

Global white matter fractional anisotropy was reduced in patients with CKD relative to controls (standardized estimate = -0.38, 95% CI -0.69:-0.07), driven by reductions within the body of the corpus callosum (standardized estimate = -0.44, 95% CI -0.75:-0.13), cerebral peduncle (SE = -0.37, 95% CI -0.67:-0.07), cingulum (hippocampus) (standardized estimate = -0.45, 95% CI -0.75:-0.14), and posterior limb of the internal capsule (standardized estimate = -0.46, 95% CI -0.76:-0.15). Medical variables and neurocognitive abilities were not significantly associated with white matter fractional anisotropy.

CONCLUSIONS

White matter development is vulnerable in children with CKD because of congenital causes, even prior to the need for dialysis or transplantation.

Spatial variation and association between maternal chemical fertilizer exposure and preterm birth in a rural area in Northern China

Whether maternal macro-environmental chemical fertilizer exposure has an association with the risk of preterm birth remains unclear. This study aimed to investigate the association between maternal exposure to chemical fertilizer during pregnancy and the risk of preterm birth. A total of 13,861 births, including 402 preterm birth from 313 villages in Pingding County, Shanxi Province, China, were analyzed to explore spatial variations of preterm birth risks at the village level. Spatial variations of preterm birth were visualized and tested with Disease Mapping, Moran's I and G* Statistic. The spatial zero-inflated negative binomial model was used to evaluate the incidence rate ratio (IRR) of preterm birth in different chemical fertilizer consumption levels at the village level. A population-based case-control study was conducted including 153 preterm births cases and 204 controls at the household level. The two-level logistic regression model was performed to estimate the association between risks of preterm birth and maternal exposure to chemical fertilizer after adjusting confounding factors. The findings indicated a remarkably clustering effect in relative risks of preterm birth and identified a high-risk clustering region of preterm birth from the south-central to the southwest and a low-risk clustering region in the northern Pingding county. The results of the spatial zero-inflated negative binomial model showed that the risk of preterm birth in the villages with chemical fertilizer consumption≥100 tons was 2.82 (95% CI: 1.50-5.57) times higher than those with <50 tons. Maternal exposure to chemical fertilizer ≥100 tons at village level was associated with an increased risk of preterm birth (aOR 2.14, 95%CI: 1.18-3.96), compared with exposure <50 tons after adjusting for confounding variables. The findings suggests that chemical fertilizers deserve more attention as a potential risk factor of preterm birth.

Fluid Homeostasis and Diuretic Therapy in the Neonate

Understanding physiologic water balance and homeostasis mechanisms in the neonate is critical for clinicians in the NICU as pathologic fluid accumulation increases the risk for morbidity and mortality. In addition, once this process occurs, treatment is limited. In this review, we will cover fluid homeostasis in the neonate, explain the implications of prematurity on this process, discuss the complexity of fluid accumulation and the development of fluid overload, identify mitigation strategies, and review treatment options.

Interventions to prevent spontaneous preterm birth in women with singleton pregnancy who are at high risk: systematic review and network meta-analysis

OBJECTIVES

To compare the efficacy of bed rest, cervical cerclage (McDonald, Shirodkar, or unspecified type of cerclage), cervical pessary, fish oils or omega fatty acids, nutritional supplements (zinc), progesterone (intramuscular, oral, or vaginal), prophylactic antibiotics, prophylactic tocolytics, combinations of interventions, placebo or no treatment (control) to prevent spontaneous preterm birth in women with a singleton pregnancy and a history of spontaneous preterm birth or short cervical length.

DESIGN

Systematic review with bayesian network meta-analysis.

DATA SOURCES

The Cochrane Pregnancy and Childbirth Group's Database of Trials, the Cochrane Central Register of Controlled Trials, Medline, Embase, CINAHL, relevant journals, conference proceedings, and registries of ongoing trials.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised controlled trials of pregnant women who are at high risk of spontaneous preterm birth because of a history of spontaneous preterm birth or short cervical length. No language or date restrictions were applied.

OUTCOMES

Seven maternal outcomes and 11 fetal outcomes were analysed in line with published core outcomes for preterm birth research. Relative treatment effects (odds ratios and 95% credible intervals) and certainty of evidence are presented for outcomes of preterm birth <34 weeks and perinatal death.

RESULTS

Sixty one trials (17 273 pregnant women) contributed data for the analysis of at least one outcome. For preterm birth <34 weeks (40 trials, 13 310 pregnant women) and with placebo or no treatment as the comparator, vaginal progesterone was associated with fewer women with preterm birth <34 weeks (odds ratio 0.50, 95% credible interval 0.34 to 0.70, high certainty of evidence). Shirodkar cerclage showed the largest effect size (0.06, 0.00 to 0.84), but the certainty of evidence was low. 17OHPC (17α-hydroxyprogesterone caproate; 0.68, 0.43 to 1.02, moderate certainty), vaginal pessary (0.65, 0.39 to 1.08, moderate certainty), and fish oil or omega 3 (0.30, 0.06 to 1.23, moderate certainty) might also reduce preterm birth <34 weeks compared with placebo or no treatment. For the fetal outcome of perinatal death (30 trials, 12 119 pregnant women) and with placebo or no treatment as the comparator, vaginal progesterone was the only treatment that showed clear evidence of benefit for this outcome (0.66, 0.44 to 0.97, moderate certainty). 17OHPC (0.78, 0.50 to 1.21, moderate certainty), McDonald cerclage (0.59, 0.33 to 1.03, moderate certainty), and unspecified cerclage (0.77, 0.53 to 1.11, moderate certainty) might reduce perinatal death rates, but credible intervals could not exclude the possibility of harm. Only progesterone treatments are associated with reduction in neonatal respiratory distress syndrome, neonatal sepsis, necrotising enterocolitis, and admission to neonatal intensive care unit compared with controls.

CONCLUSION

Vaginal progesterone should be considered the preventative treatment of choice for women with singleton pregnancy identified to be at risk of spontaneous preterm birth because of a history of spontaneous preterm birth or short cervical length. Future randomised controlled trials should use vaginal progesterone as a comparator to identify better treatments or combination treatments.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42020169006.

Prematurity and Low Birth Weight in Neonates as a Risk Factor for Obesity, Hypertension, and Chronic Kidney Disease in Pediatric and Adult Age

Low weight at birth may be due to intrauterine growth restriction or premature birth. Preterm birth is more common in low- and middle-income countries: 60% of preterm birth occur in sub-Saharan African or South Asian countries. However, in some higher-income countries, preterm birth rates appear to be increasing in relation to a reduction in the lower threshold of fetal viability. The cutoff is at 22–23 weeks, with a birth weight of approximately 500 g, although in developed countries such as Japan, the viability cutoff described is 21–22 weeks. There is evidence of the long-term consequences of prenatal programming of organ function and its relationship among adult diseases, such as hypertension (HT), central obesity, diabetes, metabolic syndrome, and chronic kidney disease (CKD). Premature delivery before the completion of nephrogenesis and intrauterine growth restriction leads to a reduction in the number of nephrons that are larger due to compensatory hyperfiltration and hypertrophy, which predisposes to the development of CKD in adulthood. In these patients, the long-term strategies are early evaluation and therapeutic interventions to decrease the described complications, by screening for HT, microalbuminuria and proteinuria, ultrasound monitoring, and renal function, with the emphasis on preventive measures. This review describes the effects of fetal programming on renal development and the risk of obesity, HT, and CKD in the future in patients with low birth weight (LBW), and the follow-up and therapeutic interventions to reduce these complications.

Relações terminológicas entre diagnósticos de enfermagem para crianças com doenças renais

RESUMO Objetivo: Identificar as relações dos enunciados de diagnósticos de enfermagem para crianças com doenças renais elaborados segundo a Classificação Internacional para a Prática de Enfermagem (CIPE®) com os diagnósticos da NANDA Internacional (NANDA-I). Métodos: Estudo metodológico operacionalizado pelas etapas: 1) Levantamento dos achados clínicos por meio de entrevista e exame físico com crianças; 2) Elaboração dos diagnósticos de enfermagem mediante o julgamento clínico de Gordon; 3) Mapeamento cruzado dos enunciados de diagnósticos entre os sistemas de classificação NANDA-I e CIPE®; 4) Validação de conteúdo utilizando a técnica Delphi, em duas rodadas, com enfermeiros especialistas. Resultados: Participaram 90 crianças. Foram elaborados 151 diagnósticos, dos quais 66,3% (n= 100) da terminologia da CIPE® e 33,7% (n= 51) da NANDA-I; 55 diagnósticos apresentaram equivalência de significados. Conclusões: O mapeamento cruzado de diagnósticos foi alcançado partindo-se da realidade de crianças, com uso de raciocínio clínico e validação por enfermeiros especialistas.

The developmental origins of health and chronic kidney disease: Current status and practices in Japan

The concept of the developmental origins of health and disease (DOHaD) views unfavorable perinatal circumstances as contributing to the development of diseases in later life. It is well known that such unfavorable circumstances play an important role as a risk factor for chronic kidney disease (CKD) in infants born with prematurity. Low birthweight (LBW) is believed to be a potential contributor to CKD in adulthood. Preterm and/or LBW infants are born with incomplete nephrogenesis. As a result, the number of nephrons is low. The poor intrauterine environment also causes epigenetic changes that adversely affect postnatal renal function. After birth, hyperfiltration of individual nephrons due to low nephron numbers causes proteinuria and secondary glomerulosclerosis. Furthermore, the risk of CKD increases as renal damage takes a second hit from exposure to nephrotoxic substances and acquired insults such as acute kidney injury after birth among infants in neonatal intensive care. Meanwhile, unfortunately, recent studies have shown that the number of nephrons in healthy Japanese individuals is approximately two-thirds lower than that in previous reports. This means that Japanese premature infants are clearly at a high risk of developing CKD in later life. Recently, several DOHaD-related CKD studies from Japanese researchers have been reported. Here, we summarize the relevance of CKD in conjunction with DOHaD and review recent studies that have examined the impact of the upward LBW trend in Japan on renal health.

Gestational Diabetes Mellitus in Europe: A Systematic Review and Meta-Analysis of Prevalence Studies

Background

Gestational Diabetes Mellitus (GDM) is defined as the type of hyperglycemia diagnosed for the first-time during pregnancy, presenting with intermediate glucose levels between normal levels for pregnancy and glucose levels diagnostic of diabetes in the non-pregnant state. We aimed to systematically review and meta-analyze studies of prevalence of GDM in European countries at regional and sub-regional levels, according to age, trimester, body weight, and GDM diagnostic criteria.

Methods

Systematic search was conducted in five databases to retrieve studies from 2014 to 2019 reporting the prevalence of GDM in Europe. Two authors have independently screened titles and abstracts and full text according to eligibility using Covidence software. A random-effects model was used to quantify weighted GDM prevalence estimates. The National Heart, Lung, and Blood Institute criteria was used to assess the risk of bias.

Results

From the searched databases, 133 research reports were deemed eligible and included in the meta-analysis. The research reports yielded 254 GDM-prevalence studies that tested 15,572,847 pregnant women between 2014 and 2019. The 133 research reports were from 24 countries in Northern Europe (44.4%), Southern Europe (27.1%), Western Europe (24.1%), and Eastern Europe (4.5%). The overall weighted GDM prevalence in the 24 European countries was estimated at 10.9% (95% CI: 10.0-11.8, I2 : 100%). The weighted GDM prevalence was highest in the Eastern Europe (31.5%, 95% CI: 19.8-44.6, I2 : 98.9%), followed by in Southern Europe (12.3%, 95% CI: 10.9-13.9, I2 : 99.6%), Western Europe (10.7%, 95% CI: 9.5-12.0, I2 : 99.9%), and Northern Europe (8.9%, 95% CI: 7.9-10.0, I2 : 100). GDM prevalence was 2.14-fold increased in pregnant women with maternal age ≥30 years (versus 15-29 years old), 1.47-fold if the diagnosis was made in the third trimester (versus second trimester), and 6.79- fold in obese and 2.29-fold in overweight women (versus normal weight).

Conclusions

In Europe, GDM is significant in pregnant women, around 11%, with the highest prevalence in pregnant women of Eastern European countries (31.5%). Findings have implications to guide vigilant public health awareness campaigns about the risk factors associated with developing GDM.

Systematic Review Registration

PROSPERO [https://www.crd.york.ac.uk/PROSPERO/], identifier CRD42020161857.

Nephron overload as a therapeutic target to maximize kidney lifespan

Kidney lifespan is a patient-oriented outcome that provides much needed context for understanding chronic kidney disease (CKD). Nephron endowment, age-associated decline in nephron number, kidney injury history and the intrinsic capacity of nephrons to adapt to haemodynamic and metabolic overload vary widely within the population. Defining percentiles of kidney function might therefore help to predict individual kidney lifespan and distinguish healthy ageing from progressive forms of CKD. In response to nephron loss, the remaining nephrons undergo functional and structural adaptations to meet the ongoing haemodynamic and metabolic demands of the organism. When these changes are no longer sufficient to maintain kidney cell homeostasis, remnant nephron demise occurs and CKD progression ensues. An individual's trajectory of glomerular filtration rate and albuminuria reflects the extent of nephron loss and adaptation of the remaining nephrons. Nephron overload represents the final common pathway of CKD progression and is largely independent of upstream disease mechanisms. Thus, interventions that efficiently attenuate nephron overload in early disease stages can protect remnant kidney cells and nephrons, and delay CKD progression. This Review provides a conceptual framework for individualized diagnosis, monitoring and treatment of CKD with the goal of maximizing kidney lifespan.

Renal morphology and glomerular capillarisation in young adult sheep born moderately preterm

Preterm birth (delivery <37 weeks of gestation) is associated with impaired glomerular capillary growth in neonates; if this persists, it may be a contributing factor in the increased risk of hypertension and chronic kidney disease in people born preterm. Therefore, in this study, we aimed to determine the long-term impact of preterm birth on renal morphology, in adult sheep. Singleton male sheep were delivered moderately preterm at 132 days (~0.9) of gestation (n = 6) or at term (147 days gestation; n = 6) and euthanised at 14.5 months of age (early adulthood). Stereological methods were used to determine mean renal corpuscle and glomerular volumes, and glomerular capillary length and surface area, in the outer, mid and inner regions of the renal cortex. Glomerulosclerosis and interstitial collagen levels were assessed histologically. By 14.5 months of age, there was no difference between the term and preterm sheep in body or kidney weight. Renal corpuscle volume was significantly larger in the preterm sheep than the term sheep, with the preterm sheep exhibiting enlarged Bowman's spaces; however, there was no difference in glomerular volume between groups, with no impact of preterm birth on capillary length or surface area per glomerulus. There was also no difference in interstitial collagen levels or glomerulosclerosis index between groups. Findings suggest that moderate preterm birth does not adversely affect glomerular structure in early adulthood. The enlarged Bowman's space in the renal corpuscles of the preterm sheep kidneys, however, is of concern and merits further research into its cause and functional consequences.

Urinary Biomarkers of Mycotoxin Induced Nephrotoxicity-Current Status and Expected Future Trends

The intensifying world-wide spread of mycotoxigenic fungal species has increased the possibility of mycotoxin contamination in animal feed and the human food chain. Growing evidence shows the deleterious toxicological effects of mycotoxins from infants to adults, while large population-based screening programs are often missing to identify affected individuals. The kidney functions as the major excretory system, which makes it particularly vulnerable to nephrotoxic injury. However, few studies have attempted to screen for kidney injury biomarkers in large, mycotoxin-exposed populations. As a result, there is an urgent need to screen them with sensitive biomarkers for potential nephrotoxicity. Although a plethora of biomarkers have been tested to estimate the harmful effects of a wide spectrum of toxicants, β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are currently the dominant biomarkers employed routinely in environmental toxicology research. Nevertheless, kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as useful and informative markers to reveal mycotoxin induced nephrotoxicity. In this opinion article we consider the nephrotoxic effects of mycotoxins, the biomarkers available to detect and quantify the kidney injuries caused by them, and to recommend biomarkers to screen mycotoxin-exposed populations for renal damage.

Kidney disease risk factors do not explain impacts of low dietary protein on kidney function and structure

The kidneys balance many byproducts of the metabolism of dietary components. Previous studies examining dietary effects on kidney health are generally of short duration and manipulate a single macronutrient. Here, kidney function and structure were examined in C57BL/6J mice randomized to consume one of a spectrum of macronutrient combinations (protein [5%–60%], carbohydrate [20%–75%], and fat [20%–75%]) from weaning to late-middle age (15 months). Individual and interactive impacts of macronutrients on kidney health were modeled. Dietary protein had the greatest influence on kidney function, where chronic low protein intake decreased glomerular filtration rates and kidney mass, whereas it increased kidney immune infiltration and structural injury. Kidney outcomes did not align with cardiometabolic risk factors including glucose intolerance, overweight/obesity, dyslipidemia, and hypertension in mice with chronic low protein consumption. This study highlights that protein intake over a lifespan is an important determinant of kidney function independent of cardiometabolic changes.

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Chronic high macronutrient intake from any source increases kidney function (GFR)

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Low protein intake led to greater kidney tubular structural injury and inflammation

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Lower protein intake decreased kidney mass and glomerular filtration capacity

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Kidney outcomes did not align with longevity or cardiometabolic outcomes

Premature differentiation of nephron progenitor cell and dysregulation of gene pathways critical to kidney development in a model of preterm birth

Preterm birth is a leading cause of neonatal morbidity. Survivors have a greater risk for kidney dysfunction and hypertension. Little is known about the molecular changes that occur in the kidney of individuals born preterm. Here, we demonstrate that mice delivered two days prior to full term gestation undergo premature cessation of nephrogenesis, resulting in a lower glomerular density. Kidneys from preterm and term groups exhibited differences in gene expression profiles at 20- and 27-days post-conception, including significant differences in the expression of fat-soluble vitamin-related genes. Kidneys of the preterm mice exhibited decreased proportions of endothelial cells and a lower expression of genes promoting angiogenesis compared to the term group. Kidneys from the preterm mice also had altered nephron progenitor subpopulations, early Six2 depletion, and altered Jag1 expression in the nephrogenic zone, consistent with premature differentiation of nephron progenitor cells. In conclusion, preterm birth alone was sufficient to shorten the duration of nephrogenesis and cause premature differentiation of nephron progenitor cells. These candidate genes and pathways may provide targets to improve kidney health in preterm infants.

Progenitor translatome changes coordinated by Tsc1 increase perception of Wnt signals to end nephrogenesis

Mammalian nephron endowment is determined by the coordinated cessation of nephrogenesis in independent niches. Here we report that translatome analysis in Tsc1+/- nephron progenitor cells from mice with elevated nephron numbers reveals how differential translation of Wnt antagonists over agonists tips the balance between self-renewal and differentiation. Wnt agonists are poorly translated in young niches, resulting in an environment with low R-spondin and high Fgf20 promoting self-renewal. In older niches we find increased translation of Wnt agonists, including R-spondin and the signalosome-promoting Tmem59, and low Fgf20, promoting differentiation. This suggests that the tipping point for nephron progenitor exit from the niche is controlled by the gradual increase in stability and possibly clustering of Wnt/Fzd complexes in individual cells, enhancing the response to ureteric bud-derived Wnt9b inputs and driving synchronized differentiation. As predicted by these findings, removing one Rspo3 allele in nephron progenitors delays cessation and increases nephron numbers in vivo.

NF-κB regulation in maternal immunity during normal and IUGR pregnancies

Intrauterine Growth Restriction (IUGR) is a leading cause of perinatal death with no effective cure, affecting 5-10% pregnancies globally. Suppressed pro-inflammatory Th1/Th17 immunity is necessary for pregnancy success. However, in IUGR, the inflammatory response is enhanced and there is a limited understanding of the mechanisms that lead to this abnormality. Regulation of maternal T-cells during pregnancy is driven by Nuclear Factor Kappa B p65 (NF-κB p65), and we have previously shown that p65 degradation in maternal T-cells is induced by Fas activation. Placental exosomes expressing Fas ligand (FasL) have an immunomodulatory function during pregnancy. The aim of this study is to investigate the mechanism and source of NF-κB regulation required for successful pregnancy, and whether this is abrogated in IUGR. Using flow cytometry, we demonstrate that p65⁺ Th1/Th17 cells are reduced during normal pregnancy, but not during IUGR, and this phenotype is enforced when non-pregnant T-cells are cultured with normal maternal plasma. We also show that isolated exosomes from IUGR plasma have decreased FasL expression and are reduced in number compared to exosomes from normal pregnancies. In this study, we highlight a potential role for FasL⁺ exosomes to regulate NF-κB p65 in T-cells during pregnancy, and provide the first evidence that decreased exosome production may contribute to the dysregulation of p65 and inflammation underlying IUGR pathogenesis.

Premature birth carries a higher risk of nephrotic syndrome: a cohort study

The pathogenesis of nephrotic syndrome is unclear. We conducted a nationwide population-based cohort study to examine the associations between preterm births and subsequent development of NS. NS was defined as ≥ 3 records with ICD-9-CM codes for NS in hospital admission or outpatient clinic visits. To avoid secondary nephrotic syndrome or nephritis with nephrotic range proteinuria, especially IgA nephropathy, we excluded patients with associated codes. A total of 78,651 preterm infants (gestational age < 37 weeks) and 786,510 matched term infants born between 2004 and 2009 were enrolled and followed until 2016. In the unadjusted models, preterm births, maternal diabetes, and pregnancy induced hypertension were associated with subsequent NS. After adjustment, preterm births remained significantly associated with NS (p = 0.001). The risk of NS increased as the gestational age decreased (p for trend < 0.001). Among the NS population, preterm births were not associated with more complications (Hypertension: p = 0.19; Serious infections: p = 0.63, ESRD: p = 0.75) or a requirement for secondary immunosuppressants (p = 0.61). In conclusion, preterm births were associated with subsequent NS, where the risk increased as the gestational age decreased. Our study provides valuable information for future pathogenesis studies.

Increasing urinary podocyte mRNA excretion and progressive podocyte loss in kidney contribute to the high risk of long-term renal disease caused by preterm birth

Podocyte abnormalities are common mechanism driving the progression of glomerular diseases, which account for most chronic kidney diseases (CKDs). However, the role of podocyte in the mechanism of high-risk long-term CKD caused by prematurity has not been well clarified. In present study, urine samples of 86 preterm infants and 32 full-term infants were collected, and podocyte-specific podocin mRNA levels in urine pellet were applied to indicate urinary podocyte mRNA excretion. In addition, in a preterm animal rat model, preterm rats were identified by delivery 2 days early. From the age of 3 weeks-12 months, urine samples were collected to examine podocyte mRNA excretion by measuring podocyte-specific podocin mRNA levels. Kidney samples at the age of 3 weeks, 2 months, and 12 months were collected from 8, 5 and 6 preterm rats and 9, 6 and 8 full-term rats, respectively, to examine podocyte density and podocyte area by measuring the podocyte specific nuclear marker WT-1 and the podocyte specific marker synaptopodin. As results, a more than threefold increase of urinary podocyte-specific podocin mRNA excretion rate was found in preterm infants compared with full-term infants. In addition, there was negative correlation between gestational age at birth and urinary podocin mRNA excretion. In preterm rats, a reduction in the total number of differentiated podocytes in glomeruli and an increased podocyte podocin mRNA excretion rate in urine were detected at the end of kidney differentiation. Moreover, long-term follow-up data in preterm rats showed there was an increased the risk of renal disease indicated by persistent podocyte mRNA loss, proteinuria, and enlarged glomeruli. In conclusion, increasing podocyte mRNA excretion in urine and podocyte loss in kidney led by prematurity drive the progression of long-term abnormal kidney function and could potentially explain the high risk of long-term CKD in preterm infants.

Insights into the Mechanisms of Fetal Growth Restriction-Induced Programming of Hypertension

In recent decades, both clinical and animal studies have shown that fetal growth restriction (FGR), caused by exposure to adverse uterine environments, is a risk factor for hypertension as well as for a variety of adult diseases. This observation has shaped and informed the now widely accepted theory of developmental origins of health and disease (DOHaD). There is a plethora of evidence supporting the association of FGR with increased risk of adult hypertension; however, the underlying mechanisms responsible for this correlation remain unclear. This review aims to explain the current advances in the field of fetal programming of hypertension and a brief narration of the underlying mechanisms that may link FGR to increased risk of adult hypertension. We explain the theory of DOHaD and then provide evidence from both clinical and basic science research which support the theory of fetal programming of adult hypertension. In addition, we have explored the underlying mechanisms that may link FGR to an increased risk of adult hypertension. These mechanisms include epigenetic changes, metabolic disorders, vascular dysfunction, neurohormonal impairment, and alterations in renal physiology and function. We further describe sex differences seen in the developmental origins of hypertension and provide insights into the opportunities and challenges present in this field.

Early Biomarkers of Hypoxia and Inflammation and Two-Year Neurodevelopmental Outcomes in the Preterm Erythropoietin Neuroprotection (PENUT) Trial

BACKGROUND

In the Preterm Erythropoietin (Epo) NeUroproTection (PENUT) Trial, potential biomarkers of neurological injury were measured to determine their association with outcomes at two years of age and whether Epo treatment decreased markers of inflammation in extremely preterm (<28 weeks' gestation) infants.

METHODS

Plasma Epo was measured (n=391 Epo, n=384 placebo) within 24h after birth (baseline), 30min after study drug administration (day 7), 30min before study drug (day 9), and on day 14. A subset of infants (n=113 Epo, n=107 placebo) had interferon-gamma (IFN-γ), Interleukin (IL)-6, IL-8, IL-10, Tau, and tumour necrosis factor-α (TNF-α) levels evaluated at baseline, day 7 and 14. Infants were then evaluated at 2 years using the Bayley Scales of Infant and Toddler Development, 3rd Edition (BSID-III).

FINDINGS

Elevated baseline Epo was associated with increased risk of death or severe disability (BSID-III Motor and Cognitive subscales <70 or severe cerebral palsy). No difference in other biomarkers were seen between treatment groups at any time, though Epo appeared to mitigate the association between elevated baseline IL-6 and lower BSID-III scores in survivors. Elevated baseline, day 7 and 14 Tau concentrations were associated with worse BSID-III Cognitive, Motor, and Language skills at two years.

INTERPRETATION

Elevated Epo at baseline and elevated Tau in the first two weeks after birth predict poor outcomes in infants born extremely preterm. However, no clear prognostic cut-off values are apparent, and further work is required before these biomarkers can be widely implemented in clinical practice.

FUNDING

PENUT was funded by the National Institute of Neurological Disorders and Stroke (U01NS077955 and U01NS077953).

Preterm or Early Term Birth and Risk of Autism

OBJECTIVES

Preterm birth has been linked with increased risk of autism spectrum disorder (ASD); however, potential causality, sex-specific differences, and association with early term birth are unclear. We examined whether preterm and early term birth are associated with ASD in a large population-based cohort.

METHODS

A national cohort study was conducted of all 4 061 795 singleton infants born in Sweden during 1973-2013 who survived to age 1 year, who were followed-up for ASD identified from nationwide outpatient and inpatient diagnoses through 2015. Poisson regression was used to determine prevalence ratios for ASD associated with gestational age at birth, adjusting for confounders. Cosibling analyses were used to assess the influence of unmeasured shared familial (genetic and/or environmental) factors.

RESULTS

ASD prevalences by gestational age at birth were 6.1% for extremely preterm (22-27 weeks), 2.6% for very to moderate preterm (28-33 weeks), 1.9% for late preterm (34-36 weeks), 2.1% for all preterm (<37 weeks), 1.6% for early term (37-38 weeks), and 1.4% for term (39-41 weeks). The adjusted prevalence ratios comparing extremely preterm, all preterm, or early term versus term, respectively, were 3.72 (95% confidence interval, 3.27-4.23), 1.35 (1.30-1.40), and 1.11 (1.08-1.13) among boys and 4.19 (3.45-5.09), 1.53 (1.45-1.62), and 1.16 (1.12-1.20) among girls (P < .001 for each). These associations were only slightly attenuated after controlling for shared familial factors.

CONCLUSIONS

In this national cohort, preterm and early term birth were associated with increased risk of ASD in boys and girls. These associations were largely independent of covariates and shared familial factors, consistent with a potential causal relationship.

Adults Born Preterm: Long-Term Health Risks of Former Very Low Birth Weight Infants

BACKGROUND

Advances in neonatology now enable increasing numbers of very low birth weight neonates (<1500 g) to survive into early adulthood and beyond. What are the implications for their long-term care?

METHODS

Selective literature search on the outcome of very low birth weight neonates in adulthood ("adults born preterm").

RESULTS

Robust data are available on the pulmonary, metabolic, cardiovascular, renal, neurocognitive, sensory-visual, social-emotional, mental, reproductive, and musculoskeletal long-term risks. On the somatic level, elevated rates have been documented for asthma (odds Ratio [OR] 2.37), diabetes mellitus (OR 1.54), and chronic renal disease (hazard ratio [HR] 3.01), along with the cardiovascular and cerebrovascular sequelae of a tendency toward arterial hypertension. On the psychosocial level, the main findings are deficits in romantic partnerships (OR 0.72) and a lower reproduction rate (relative risk [RR] male/female 0.24/0.33). The affected women also have an elevated risk of preterm delivery.

CONCLUSION

A risk profile with both somatic and psychosocial aspects can be discerned for adults who were born prematurely, even if some of these risks are present in low absolute numbers. As the ability to compensate for latent deficits declines with age, such adults may suffer from "premature aging as the late price of premature birth." A holistic approach to care with personalized prevention strategies-which for most of them was discontinued at discharge from pediatric follow-up-therefore seems appropriate in adulthood as well.

Effects of prematurity on long-term renal health: a systematic review

OBJECTIVE

To investigate the literature and determine if prematurity has an impact on long-term adverse kidney outcomes.

DESIGN

Systematic review.

DATA SOURCES

OVID Medline, PubMed, SCOPUS, CINAHL and EMBASE databases were searched for studies relating to the adverse outcomes of prematurity from 1990 to April 2021.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

All articles published between January 1990 and April 2021 that investigated whether premature infants developed long-term adverse renal outcomes were included in this review. Articles must have been human studies and written in English. Case series with less than 20 participants and case studies were excluded.

DATA EXTRACTION AND SYNTHESIS

One reviewer completed the database searches. Article selection was performed independently and in a non-blinded manner by both reviewers. Initial screening was by title and abstract. Full texts of remaining articles were reviewed. Articles for which inclusion was unclear were re-reviewed by both reviewers, and a unanimous decision was taken as to whether they should be included. The Newcastle-Ottawa Scale was used for quality assessment of the included articles.

RESULTS

The literature search yielded 31 human studies, which investigated the short-term and long-term kidney outcomes of prematurity. These studies were conducted in 17 different countries. The most common outcomes measured were blood pressure (BP) and glomerular filtration rate. Other common outcomes measured included kidney size and mass, proteinuria, albuminuria, chronic kidney disease (CKD) and physical parameters such as height, weight and body mass index.

CONCLUSION

Prematurity is likely linked to increased risk of kidney dysfunction and high BP in childhood and into early adulthood. Premature birth conferred a twofold increased risk of CKD and extremely premature birth conferred a threefold increased risk of CKD. However, further larger multicentre studies are needed to draw definitive conclusions on the long-term kidney outcomes of prematurity.

Is the estimated glomerular filtration rate formula useful for evaluating the renal function of Down syndrome?

BACKGROUND

Children with Down syndrome (DS) have different growth rates compared with normal children. The present study examined the reliability of a general formula, Uemura's formula, utilized in normal Japanese children to estimate renal function (estimated glomerular filtration rate - eGFR) in children with DS.

METHODS

This study included 758 children aged 2-18 years with DS who visited our medical center. Patients with congenital heart disease, or congenital anomalies of the kidney or urinary tract detected via abdominal ultrasonography, chronic glomerulonephritis, and vesicoureteral reflux, etc., were excluded. Height and serum creatinine data gathered from 2421 examinations of 379 children with DS (224 boys and 155 girls) were used to evaluate Uemura's formula.

RESULTS

The mean eGFR was lower in children with DS than in children without DS. Stage II chronic kidney disease was indicated in 44.6% of examinations and stage III in 0.8%. The association of eGFR with age differed between sexes. Boys with DS showed a significant but weak negative correlation between eGFR and age (r = -0.273, P < 0.001), whereas girls with DS showed a significant but very weak negative correlation (r = -0.111, P < 0.001).

CONCLUSIONS

A new eGFR formula that takes into account specific growth rates and puberty is needed for children with DS because general renal function evaluation formulas are inappropriate for these patients.

The Evaluation of Kidney Function in Living Kidney Donor Candidates

Living kidney donors incur a small increased risk of ESKD, of which predonation GFR is an important determinant. As a result, kidney function assessment is central to the donor candidate evaluation and selection process. This article reviews the different methods of GFR assessment, including eGFR, creatinine clearance, and measured GFR, and the current guidelines on GFR thresholds for donor acceptance. eGFR obtained using the 2009 CKD Epidemiology Collaboration equation that, although the best of estimating estimations, tends to underestimate levels and has limited accuracy, especially near-normal GFR values. In the United States, the Organ Procurement and Transplantation Network policy on living donation mandates either measured GFR or creatinine clearance as part of the evaluation. Measured GFR is considered the gold standard, although there is some variation in performance characteristics, depending on the marker and technique used. Major limitations of creatinine clearance are dependency on accuracy of timed collection, and overestimation as a result of distal tubular creatinine secretion. GFR declines with healthy aging, and most international guidelines recommend use of age-adapted selection criteria. The 2017 Kidney Disease: Improving Global Outcomes Guideline for the Evaluation and Care of Living Kidney Donors diverges from other guidelines and recommends using absolute cutoff of <60 ml/min per 1.73m² for exclusion and ≥90 ml/min per 1.73m² for acceptance, and determination of candidacy with intermediate GFR on the basis of long-term ESKD risk. However, several concerns exist for this strategy, including inappropriate acceptance of younger candidates due to underestimation of risk, and exclusion of older candidates whose kidney function is in fact appropriate for age. The role of cystatin C and other newer biomarkers, and data on the effect of predonation GFR on not just ESKD risk, but also advanced CKD risk and cardiovascular outcomes are needed.

Association of Preterm Birth With Long-term Risk of Heart Failure Into Adulthood

IMPORTANCE

Preterm birth has been associated with increased risk of heart failure (HF) early in life, but its association with new-onset HF in adulthood appears to be unknown.

OBJECTIVE

To determine whether preterm birth is associated with increased risk of HF from childhood into mid-adulthood in a large population-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

This national cohort study was conducted in Sweden with data from 1973 through 2015. All singleton live births in Sweden during 1973 through 2014 were included.

EXPOSURES

Gestational age at birth, identified from nationwide birth records.

MAIN OUTCOMES AND MEASURES

Heart failure, as identified from inpatient and outpatient diagnoses through 2015. Cox regression was used to determine hazard ratios (HRs) for HF associated with gestational age at birth while adjusting for other perinatal and maternal factors. Cosibling analyses assessed for potential confounding by unmeasured shared familial (genetic and/or environmental) factors.

RESULTS

A total of 4 193 069 individuals were included (maximum age, 43 years; median age, 22.5 years). In 85.0 million person-years of follow-up, 4158 persons (0.1%) were identified as having HF (median [interquartile range] age, 15.4 [28.0] years at diagnosis). Preterm birth (gestational age <37 weeks) was associated with increased risk of HF at ages younger than 1 year (adjusted HR [aHR], 4.49 [95% CI, 3.86-5.22]), 1 to 17 years (aHR, 3.42 [95% CI, 2.75-4.27]), and 18 to 43 years (aHR, 1.42 [95% CI, 1.19-1.71]) compared with full-term birth (gestational age, 39-41 weeks). At ages 18 through 43 years, the HRs further stratified by gestational age were 4.72 (95% CI, 2.11-10.52) for extremely preterm births (22-27 weeks), 1.93 (95% CI, 1.37-2.71) for moderately preterm births (28-33 weeks), 1.24 (95% CI, 1.00-1.54) for late preterm births (34-36 weeks), and 1.09 (95% CI, 0.97-1.24) for early term births (37-38 weeks). The corresponding HF incidence rates (per 100 000 person-years) at ages 18 through 43 years were 31.7, 13.8, 8.7, and 7.3, respectively, compared with 6.6 for full-term births. These associations persisted when excluding persons with structural congenital cardiac anomalies. The associations at ages 18 through 43 years (but not <18 years) appeared to be largely explained by shared determinants of preterm birth and HF within families. Preterm birth accounted for a similar number of HF cases among male and female individuals.

CONCLUSIONS AND RELEVANCE

In this large national cohort, preterm birth was associated with increased risk of new-onset HF into adulthood. Survivors of preterm birth may need long-term clinical follow-up into adulthood for risk reduction and monitoring for HF.

Pregnancy-related acute kidney injury at high altitude: a retrospective observational study in a single center

Background

Pregnancy-related acute kidney injury (Pr-AKI) is associated with maternal and fetal morbidity and mortality. There are few studies focusing on Pr-AKI at high altitude in the literature.

Objectives

to investigate the incidence, etiology, clinical features and maternal-fetal outcomes of Pr-AKI in women living at high altitude.

Methods

6,512 pregnant women attending the Department of Obstetrics & Gynecology at local hospital from January 2015 to December 2018 were screened for Pr-AKI. Patients with serum creatinine above normal range(> 70umol/L) then underwent assessment to confirm the diagnosis of Pr-AKI. AKI was diagnosed and staged based on Kidney Disease Improving Global Outcomes(KDIGO) guideline. Individuals meeting the Pr-AKI criteria were recruited. Their clinical data were recorded and retrospectively analyzed.

Results

Pr-AKI was identified in 136/6512(2.09 %) patients. Hypertensive disorders of pregnancy(HDP) was the leading cause of Pr-AKI(35.3 %). 4(2.9 %) women died and the majority(86.1 %) had recovered renal function before discharge. Fetal outcomes were confirmed in 109 deliveries with gestational age ≥ 20 weeks. Pre-term delivery occurred in 30(27.3 %) cases and perinatal deaths in 17(15.5 %). The rate of low birth weight infant(LBWI) and intrauterine growth restriction(IUGR) was 22.0 and 10.9 % respectively. 16(14.5 %) infants were admitted to NICU after birth. Patients with HDP had a higher cesarean rate(56.3 %). More IUGR(25.0 %) and LBWI(37.8 %) were observed in their infants with a higher risk of admission to NICU(22.0 %). High altitude might have an adverse impact on HDP-related Pr-AKI patients with earlier terminated pregnancy and more stillbirth/neonatal death. Logistic regression models indicated that uncontrolled blood pressure, high altitude and advanced AKI were associated with adverse fetal outcomes in HDP-related Pr-AKI patients.

Conclusions

Pr-AKI was not rare in high-altitude regions and caused severe fetal morbidities and mortalities. Uncontrolled blood pressure, high altitude and advanced AKI were all risk factors for adverse fetal outcomes in Pr-AKI patients, especially for those with hypertensive disorders of pregnancy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02418-7.

Childhood risk factors for adulthood chronic kidney disease

Chronic kidney disease (CKD) is a major public health challenge, affecting as much as 8 to 18% of the world population. Identifying childhood risk factors for future CKD may help clinicians make early diagnoses and initiation of preventive interventions for CKD and its attendant comorbidities as well as monitoring for complications. The purpose of this review is to describe childhood risk factors that may predict development of overt kidney disease later in life. Currently, there are multiple childhood risk factors associated with future onset and progression of CKD. These risk factors can be grouped into five categories: genetic factors (e.g., monogenic or risk alleles), perinatal factors (e.g., low birth weight and prematurity), childhood kidney diseases (e.g., congenital anomalies, glomerular diseases, and renal cystic ciliopathies), childhood onset of chronic conditions (e.g., cancer, diabetes, hypertension, dyslipidemia, and obesity), and different lifestyle factors (e.g., physical activity, diet, and factors related to socioeconomic status). The available published information suggests that the lifelong risk for CKD can be attributed to multiple factors that appear already during childhood. However, results are conflicting on the effects of childhood physical activity, diet, and dyslipidemia on future renal function. On the other hand, there is consistent evidence to support follow-up of high-risk groups.

Maturation of glomerular filtration rate in neonates and infants: an overview

Glomerular filtration rate (GFR) increases progressively throughout fetal life, matures rapidly after birth according to gestational and post-menstrual age, and reaches adult values by 1-year post-natal age. GFR is considered the best marker of kidney function, and in clinical practice, estimated GFR is useful to anticipate complications, establish prognosis, and facilitate treatment decisions. This review article summarizes the maturation of glomerular filtration and the factors and conditions that modulate and impair developing glomerular filtration, and discusses the techniques available to assess GFR in neonates and infants. We focused on simple, reliable, easily available, and cheap techniques to estimate GFR, which may provide valuable information on the renal aspects of the clinical care of this group of patients.

Renal insufficiency in children born preterm: examining the role of neonatal acute kidney injury

OBJECTIVE

To identify the prevalence of renal insufficiency (RI) in children with a history of prematurity and acute kidney injury (AKI).

STUDY DESIGN

This prospective cohort study evaluated renal function in children born preterm at 5-9 years of age. Univariable analyses compared perinatal and follow-up data from subjects with and without AKI history, and with and without current RI. Regression analyses were attempted to model RI as a function of AKI and other clinical risk factors.

RESULTS

Fifteen of 43 (35%) participants had previously undiagnosed RI. Only children with no AKI history or neonatal stage 1 AKI presented for follow-up. Children born preterm with a history of stage 1 AKI had higher serum creatinine (sCr) at follow-up, but were not more likely to have RI compared to children without stage 1 AKI history (RI prevalence 30% and 36% in AKI and non-AKI group, respectively).

CONCLUSION

The high prevalence of RI in this preterm cohort at middle childhood follow-up highlights the need for routine kidney health assessments in this population. Large multicenter studies are needed to further characterize the impact of premature birth and mild AKI on renal function throughout childhood.

The implications of routine milk fortification for the short and long-term health of preterm babies

Fortification refers to the practice of enriching human milk feeds for very preterm babies with macronutrients, minerals and vitamins. Though standard of care in some parts of the world, adoption of fortification is not universal. Fortification entered into use on the assumption that human milk macronutrient content, principally protein, is insufficient to support the growth and development of very preterm babies. However, because of the substantial variability in human milk composition, routine fortification risks exposing some babies to very high protein intakes, which may be dangerous. Some clinicians fear fortification with cow-milk derived products will increase the risk of necrotising enterocolitis, leading them to favour commercial fortifiers made from pooled human milk over cow milk based products, a practice that has additional ethical implications. Randomised controlled trials of multi-nutrient fortification to-date are inadequate. No trial has had power to detect important functional effects; the majority are methodologically weak and focus primarily upon short-term growth. Evidence to guide practice is inadequate. There is an urgent need for collaboration to conduct high-quality research to end these long-standing uncertainties.