Perinatal factors contributing to chronic kidney disease in a cohort of Japanese children with very low birth weight

Case-control study on long-term kidney outcomes in very low birth weight infants: impact of growth restriction and maternal preeclampsia

OBJECTIVE

To identify factors, particularly neonatal acute kidney injury, associated with an increased risk of developing chronic kidney disease (CKD) within the first 10 years of life in children with a history of prematurity and very low birth weight (VLBW).

METHODS

This nested case-control study was conducted on VLBW infants (> 500 g and < 1.500 g) born between 2012 and 2022. The population (n = 119) included children who developed CKD (n = 55) and controls with normal findings (n = 64). CKD was defined by abnormal blood pressure, reduced glomerular filtration rate, or elevated urinary albumin excretion. Data on neonatal and maternal factors were analyzed using logistic regression to identify predictors of CKD.

RESULTS

Of the 267 eligible children 119 were included, with a median age of 32 months, and median gestational age and birth weight of 30 weeks and 1170 g, respectively. Children with CKD had lower birth weight Z-scores (-1.06 vs. -0.89), a higher occurrence of extrauterine growth restriction (EUGR) (72 % vs. 51 %), and an increased likelihood of maternal preeclampsia exposure. Maternal preeclampsia was identified as an independent predictor of CKD, associated with a 5 % increase in the odds of developing the condition (OR 1.05, 95 % CI 1.01-1.66).

CONCLUSION

Maternal preeclampsia was associated with CKD in children with a history of VLBW. This finding highlights the importance of long-term follow-up and early identification of at-risk individuals.

Continuous increase in podocyte numbers in the first 36 months of life-insights from forensic autopsies in Japanese children

BACKGROUND

Podocyte depletion is a critical factor in glomerulosclerosis development. While podocyte numbers per glomerulus typically decline with age in adults, they are hypothesized to increase during childhood. However, studies on podocyte number progression in childhood have been limited.

METHODS

This retrospective analysis examined forensic autopsy cases of Japanese children without kidney disease, aged under 192 months, between April 2010 and March 2023. Podocytes were identified using immunostaining with an anti-transducin-like enhancer of split 4 antibody and p57. Podometric parameters were estimated using the correction factor method, allowing estimation from a single histologic section.

RESULTS

This study included 68 cases with a median age of 9 months (interquartile range [IQR], 4-78). All podometric parameters correlated with age. Children younger than 36 months displayed significantly fewer podocyte numbers per glomerulus (median, 517; IQR, 483-546) compared to those aged 36 months and older (median, 616; IQR, 595-649; p < 0.001). Regression analysis revealed a significant age-related increase in podocyte numbers per glomerulus in children under 36 months (slope, 3.76; p < 0.001; 95% confidence interval [CI], 2.34-5.19), but not in those aged 36 months and older (slope, 0.25; p = 0.16; 95% CI, - 0.10-0.61). Additionally, the change in the slope at 36 months was significant (p < 0.001; 95% CI, 1.02-2.49); however, this increase did not appear linked to podocyte division.

CONCLUSIONS

Podocyte numbers per glomerulus increased from birth until 36 months and then stabilized. These findings could facilitate the development of novel treatments for chronic kidney disease caused by glomerulosclerosis and contribute to pediatric kidney health research.

Chronic kidney disease associated with extremely premature birth and extremely low birth weight may progress through the burden of growth

Chronic kidney disease associated with low birth weight and/or premature birth (L/P-CKD) in infants may result from a decreased number of nephrons at birth. These infants may develop acute kidney injury due to exposure to nephrotoxic substances or other events during nephrogenesis in early infancy. Nonetheless, L/P-CKD progression remains unclear. We present three cases of L/P-CKD diagnosed after neonatal intensive care unit (NICU) discharge. Three patients were born extremely prematurely (gestational age, 24-26 weeks) with extremely low birth weight (606-906 g). They were admitted to the NICU (117-311 days) anad received several nephrotoxic medications during the early postnatal period. They showed elevated serum creatinine levels at 4 weeks after birth, which decreased to normal levels at NICU discharge. Proteinuria was first detected during adolescence (10-15 years) on annual school urine screening, with a remarkable increase in their height (18 - 50.8 cm), without known episodes of urinary tract infection, dehydration, lifestyle-related issues, such as excessive salt/protein intake, and extreme lack of exercise that might have caused kidney damage. Their kidneys were smaller than normal on renal ultrasonography. Open renal biopsy findings indicated glomerulomegaly and perihilar glomerulosclerosis in two of the three patients, suggesting glomerular hypertension. The remarkable differences between the body height before CKD and the timing of diagnosis of CKD could contribute to the progress of CKD. Long-term follow-up of low birth weight and extremely premature infants, from NICU discharge until adulthood, should be established.

Perinatal risk factors associated with acute kidney injury severity and duration among infants born extremely preterm

BACKGROUND

We evaluated time-varying perinatal risk factors associated with early (≤7 post-natal days) and late (>7 post-natal days) severe acute kidney injury (AKI) occurrence and duration.

METHODS

A secondary analysis of Preterm Erythropoietin Neuroprotection Trial data. We defined severe AKI (stage 2 or 3) per neonatal modified Kidney Disease: Improving Global Outcomes criteria. Adjusted Cox proportional hazards models were conducted with exposures occurring at least 72 h before severe AKI. Adjusted negative binomial regression models were completed to evaluate risk factors for severe AKI duration.

RESULTS

Of 923 participants, 2% had early severe AKI. In the adjusted model, gestational diabetes (adjusted HR (aHR) 5.4, 95% CI 1.1-25.8), non-steroidal anti-inflammatory drugs (NSAIDs) (aHR 3.2, 95% CI 1.0-9.8), and vancomycin (aHR 13.9, 95% CI 2.3-45.1) were associated with early severe AKI. Late severe AKI occurred in 22% of participants. Early severe AKI (aHR 2.5, 95% CI 1.1-5.4), sepsis (aHR 2.5, 95% CI 1.4-4.4), vasopressors (aHR 2.9, 95% CI 1.8-4.6), and diuretics (aHR 2.6, 95% CI 1.9-3.6) were associated with late severe AKI. Participants who had necrotizing enterocolitis or received NSAIDs had longer severe AKI duration.

CONCLUSION

We identified major risk factors for severe AKI that can be the focus of future research.

IMPACT STATEMENT

Time-dependent risk factors for severe acute kidney injury (AKI) and its duration are not well defined among infants born <28 weeks' gestation. Over 1 in 5 infants born <28 weeks' gestation experienced severe AKI, and this study identified several major time-dependent perinatal risk factors occurring within 72 h prior to severe AKI. This study can support efforts to develop risk stratification and clinical decision support to help mitigate modifiable risk factors to reduce severe AKI occurrence and duration.

Association of Maternal and Neonatal Birth Outcomes With Subsequent Pediatric Transplants

BACKGROUND

We identified maternal and neonatal birth characteristics that were associated with organ or tissue transplants during childhood.

METHODS

We designed a retrospective cohort study of the population of children born between 2006 and 2019 in Quebec, Canada. The exposure included birth complications such as congenital anomaly, neonatal blood transfusion, and oligohydramnios. The main outcome measure was organ or tissue transplantation before 14 y of age. We categorized transplants according to type (major organs versus superficial tissues). To determine the association of birth characteristics with risk of pediatric transplant, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) using Cox proportional hazards models adjusted for potential confounders.

RESULTS

The cohort comprised 1 038 375 children with 7 712 678 person-years of follow-up, including 436 children who had transplants before 14 y of age. Birth complications were predominantly associated with major organ transplants. Congenital anomaly was associated with heart or lung (HR, 10.41; 95% CI, 5.33-20.33) and kidney transplants (HR, 13.69; 95% CI, 7.48-25.06), compared with no anomaly. Neonatal blood transfusion was associated with all major organ transplants, compared with no transfusion. Maternal complications were not as strongly associated with the risk of childhood transplant, although oligohydramnios was associated with 16.84 times (95% CI, 8.09-35.02) the risk of kidney transplant, compared with no oligohydramnios.

CONCLUSIONS

Adverse birth outcomes such as congenital anomaly, neonatal blood transfusion, and maternal oligohydramnios are associated with a greater risk of transplantation before 14 y of age. Maternal and neonatal birth outcomes may be useful predictors of transplantation.

Risk factors for childhood chronic kidney disease: a population-based study

BACKGROUND

The population-based prevalence and risk factors of childhood chronic kidney disease (CKD) are not well-defined. We ascertained childhood CKD epidemiology and perinatal risk factors, based on a large computerized medical record database that covers most of southern Israel's population.

METHODS

Pre- and post-natal records of 79,374 eligible children (with at least one serum creatinine test) born during 2001-2015 were analyzed. "Ever-CKD" was defined as ≥ 2 estimated glomerular filtration rate (eGFR) values < 60 ml/min/1.73 m² beyond age 2 years, more than 3 months apart. The last CKD status was determined on March 2019.

RESULTS

Of 82 (0.1%) patients with ever-CKD, 35 (42.7%) had their first abnormal eGFR identified already at age 2 years. In multiple logistic regression analysis, congenital anomalies of kidney and urinary tract (CAKUT)-related diagnoses, glomerulopathy, maternal oligohydramnios, small for gestational age, prematurity (under 34 weeks), post-term delivery, and small for gestational age at birth were significant risk factors for ever-CKD (odds ratio (95% confidence interval): 44.34(26.43-74.39), 64.60(32.42-128.70), 5.54(3.01-10.19), 2.02(1.25-3.28), 4.45(2.13-9.28), 2.96(1.28-6.86 and 2.02(1.25-3.28), respectively). Seventy children with ever-CKD (85.4%) had a depressed eGFR (< 90 ml/min/1.73 m²) on the last assessment (current-CKD), yielding a prevalence of 882/million.

CONCLUSIONS

CKD is more prevalent among children in southern Israel than previously reported, even after excluding those with aborted-CKD. Prenatal conditions increase the risk to develop CKD in childhood. Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information.

Epidemiology of pediatric chronic kidney disease/kidney failure: learning from registries and cohort studies

Although the concept of chronic kidney disease (CKD) in children is similar to that in adults, pediatric CKD has some peculiarities, and there is less evidence and many factors that are not clearly understood. The past decade has witnessed several additional registry and cohort studies of pediatric CKD and kidney failure. The most common underlying disease in pediatric CKD and kidney failure is congenital anomalies of the kidney and urinary tract (CAKUT), which is one of the major characteristics of CKD in children. The incidence/prevalence of CKD in children varies worldwide. Hypertension and proteinuria are independent risk factors for CKD progression; other factors that may affect CKD progression are primary disease, age, sex, racial/genetic factors, urological problems, low birth weight, and social background. Many studies based on registry data revealed that the risk factors for mortality among children with kidney failure who are receiving kidney replacement therapy are younger age, female sex, non-White race, non-CAKUT etiologies, anemia, hypoalbuminemia, and high estimated glomerular filtration rate at dialysis initiation. The evidence has contributed to clinical practice. The results of these registry-based studies are expected to lead to new improvements in pediatric CKD care.

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.

Developmental origins of disease highlight the immediate need for expanded access to comprehensive prenatal care

The prenatal environment plays a critical role in shaping fetal development and ultimately the long-term health of the child. Here, we present data linking prenatal health, via maternal nutrition, comorbidities in pregnancy (e.g., diabetes, hypertension), and infectious and inflammatory exposures, to lifelong health through the developmental origins of disease framework. It is well-established that poor maternal health puts a child at risk for adverse outcomes in the first 1,000 days of life, yet the full health impact of the in utero environment is not confined to this narrow window. The developmental origins of disease framework identifies cognitive, neuropsychiatric, metabolic and cardiovascular disorders, and chronic diseases in childhood and adulthood that have their genesis in prenatal life. This perspective highlights the enormous public health implications for millions of pregnancies where maternal care, and therefore maternal health and fetal health, is lacking. Despite near universal agreement that access to antenatal care is a priority to protect the health of women and children in the first 1,000 days of life, insufficient progress has been achieved. Instead, in some regions there has been a political shift toward deprioritizing maternal health, which will further negatively impact the health and safety of pregnant people and their children across the lifespan. In this article we argue that the lifelong health impact attributed to the perinatal environment justifies policies aimed at improving access to comprehensive antenatal care globally.

Association Analysis in Children Born from Normal and Complicated Pregnancies-Cardiovascular Disease Associated microRNAs and the Incidence of Prehypertension/Hypertension, Overweight/Obesity, Valve Problems and Heart Defects

The goal was to assess how a history of any kind of pregnancy-related complication altered expression profile of microRNAs played a role in the pathogenesis of diabetes, cardiovascular and cerebrovascular diseases in the peripheral blood leukocytes of children at the age of 3–11 years. The prior exposure to gestational hypertension, preeclampsia, fetal growth restriction, gestational diabetes mellitus, preterm prelabor rupture of membranes or spontaneous preterm birth causes that a significant proportion of children (57.42% to 90.0% specifically) had a substantially altered microRNA expression profile, which might be the origin of a lifelong cardiovascular risk. A total of 23 out of 29 tested microRNAs were upregulated in children born from such complicated gestation. The occurrence of overweight, obesity, valve problems and heart defects even intensified upregulation of microRNAs already present in children exposed to such pregnancy complications. The occurrence of overweight/obesity (miR-92a-3p, and miR-210-3p) and valve problems or heart defects (miR-342-3p) induced microRNA upregulation in children affected with pregnancy complications. Overall, 42.86% overweight/obese children and 27.36% children with valve problems or heart defects had even higher microRNA levels than children with normal clinical findings after complicated pregnancies. In addition, the microRNA expression profile was also able to differentiate between children descending from normal gestation in relation to the occurrence of overweight and obesity. Screening on the base of the combination of 19 microRNAs identified 70.0% overweight/obese children at 90.0% specificity. In general, children after complicated pregnancies, just as children after normal pregnancies, with abnormal findings are at a higher risk of the onset of cardiovascular complications, and their dispensarization, with the aim to implement primary prevention strategies, would be beneficial.