Renal development in the fetus and premature infant

The Effect of Preterm Birth on Renal Development and Renal Health Outcome

Preterm birth is associated with adverse renal health outcomes including hypertension, chronic kidney disease, and an increased rate of progression to end-stage renal failure. This review explores the antenatal, perinatal, and postnatal factors that affect the functional nephron mass of an individual and contribute to long-term kidney outcome. Health-care professionals have opportunities to increase their awareness of the risks to kidney health in this population. Optimizing maternal health around the time of conception and during pregnancy, providing kidney-focused supportive care in the NICU during postnatal nephrogenesis, and avoiding accelerating nephron loss throughout life may all contribute to improved long-term outcomes. There is a need for ongoing research into the long-term kidney outcomes of preterm survivors in mid-to-late adulthood as well as a need for further research into interventions that may improve ex utero nephrogenesis.

Anhydramnios in the Setting of Renal Malformations: The National Institutes of Health Workshop Summary

Anhydramnios in the setting of severe malformations of the fetal kidney and urinary tract is associated with a high incidence of stillbirths and life-threatening complications, including severe pulmonary hypoplasia, umbilical cord compression, and perinatal asphyxia. To prevent such adverse outcomes, some centers in the United States and elsewhere are offering amniotic fluid restoration for women diagnosed with anhydramnios in the setting of fetal renal malformations. The procedures include infusions of amniotic fluid substitutes (normal saline), percutaneously or through an amnioport-an implanted system for serial or continuous infusion of normal saline to maintain the desired amniotic fluid volume. The procedures are intended to prevent pulmonary hypoplasia and allow the pregnancy to progress closer to term gestation, enabling postnatal renal management, including long-term dialysis and renal transplantation. However, these procedures have not been recommended as standard of care by the professional societies because there are many knowledge gaps, including few data on short-term and long-term renal outcomes. The available diagnostic methods do not provide reliable prognostic information, and the current maternal and fetal interventions have not been standardized. To address these unresolved issues and to propose a research agenda, the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Institute of Diabetes and Digestive and Kidney Diseases invited a panel of experts to a workshop in August 2016. This report provides a summary of that meeting.

Is an analysis of copy number variants necessary for various types of kidney ultrasound anomalies in fetuses?

Background

This study aimed to estimate the associations of copy number variants (CNVs) with fetal kidney ultrasound anomalies. A total of 331 fetuses with kidney ultrasound anomalies who underwent prenatal chromosomal microarray analyses were enrolled. The fetuses were classified into groups with isolated and nonisolated anomalies or according to the types of kidney anomalies.

Results

Clinically significant CNVs were identified in 3.4% or 7.3% of fetuses with isolated or nonisolated kidney anomalies, respectively. CNVs were more frequently identified in fetuses with abnormal embryonic migration of the kidneys (6.6%) than in fetuses with malformations of the renal parenchyma (4.7%) or anomalies of the urinary collecting system (3.4%). In particular, CNVs were most frequently detected in fetuses with ectopic kidneys (9.5%) but not in fetuses with horseshoe kidneys or isolated duplex kidneys. Among these CNVs, the most common were del(17)(q12q12) (1.2%) and del(22)(q11q11) (0.6%). The dup(17)(p12p12) and del(15)(q11.2q11.2) CNVs were identified in this study but not in previous studies. The del(X)(p11.4p11.4) and del(16)(p13.3p13.3) CNVs were further implicated as associated with kidney anomalies.

Conclusions

Fetuses with abnormal embryonic migration of the kidneys (particularly ectopic kidneys) showed a higher frequency of clinically significant CNVs, whereas fetuses with horseshoe kidneys or duplex kidneys were less frequently associated with these CNVs.

Prevalence, types, and malformations in congenital anomalies of the kidney and urinary tract in newborns: a retrospective hospital-based study

Background

Congenital anomalies of the kidney and urinary tract (CAKUTs) are some of the most common birth defects affecting newborns. CAKUTs often have poor birth outcomes owing to the limited experience of physicians in developing countries regarding antenatal and postnatal diagnosis. We aimed to estimate the epidemiology of CAKUTs using data from a hospital-based registry in Zhejiang Province, China.

Methods

We included a total of 2790 newborns with CAKUTs, identified among 1,748,038 births during 2010–2016. The prevalence and type of CAKUTs, maternal and neonatal characteristics, and associated malformations were analyzed.

Results

The average prevalence of CAKUTs born to mothers overall and mothers aged ≥35 years were both around 1.60 per 1000 births (95% confidence interval (CI), 1.54–1.66; 95% CI, 1.44–1.83, respectively) during the study period. The prevalence of CAKUTs changed over time among all women and women of advanced maternal age, although no significant trends were observed. CAKUTs were more likely to occur in male than female newborns (odds ratio (OR) 1.28, 95% CI 1.18–1.38), in multiple births than singletons (OR 1.53, 95% CI 1.21–1.92) and in urban areas than rural areas (OR 1.27, 95% CI 1.18–1.37). The overall prenatal detection rate of CAKUTs was 73.87%. The average gestational age at antenatal diagnosis was 26.57 ± 8.70 weeks. A total 22.69% CAKUTs had associated malformations. Congenital heart defects were the most common anomalies, accounting for 8.89% of the whole population. The main proportion in subgroups was hydronephrosis, representing 31.79% of registered CAKUTs.

Conclusions

There was a nearly twofold increase in the prevalence of CAKUTs from 2010 to 2016 in Zhejiang Province. CAKUTs are strongly associated with male sex, multiple births, urban areas, and other nonurinary congenital malformations.

Full normalization of severe hypertension after parathryoidectomy - a case report and systematic review

Background

Although the relationship between hyperparathyroidism and hypertension has been described for decades, the role of hyperparathyroidism in hypertension in dialysis is still unclear. Following the case of a severely hypertensive dialysis patient, in which parathyroidectomy (PTX) corrected the metabolic imbalance and normalized blood pressure (BP), we tried to contextualize our observation with a systematic review of the recent literature on the effect of PTX on BP.

Case presentation

A dialysis patient, aged 19 years at the time of this report, with chronic kidney disease (CKD) from childhood; he was an early-preterm baby with very low birth weight (910 g), and is affected by a so-far unidentified familial nephropathy. He started dialysis in emergency at the age of 17. Except for low-dose Bisoprolol, he refused all chronic medication; hypertension (165–200/90–130 mmHg) did not respond to attainment of dry weight (Kt/V > 1.7; BNP 70–200 pg/ml pre-dialysis). He underwent subtotal PTX 1 year after dialysis start; after PTX, his blood pressure stabilized in the 100–140/50–80 range, and is normal without treatment 5 months later.

Conclusion

Our patient has some peculiar features: he is young, has a non-immunologic disease, poor compliance to drug therapy, excellent dialysis efficiency. His lack of compliance allows observing the effect of PTX on BP without pharmacologic interference.

The prompt, complete and long-lasting BP normalization led us to systematic review the current literature (Pubmed, Embase, Cochrane Collaboration 2000–2016) retrieving 8 case series (194 cases), and one case report (3 patients).

The meta-analysis showed a significant, albeit moderate, improvement in BP after PTX (difference: systolic BP -8.49 (CI 2.21–14.58) mmHg; diastolic BP -4.14 (CI 1.45–6.84) mmHg); analysis is not fully conclusive due to lack of information on anti-hypertensive agents. The 3 cases reported displayed a sharp reduction in BP after PTX.

In summary, PTX may have a positive influence on BP control, and may result in complete correction or even hypotension in some patients. The potential clinical relevance of this relationship warrants prospective large-scale studies.

[Monitoring of kidney injury in preterm infants]

Acute kidney injury (AKI) is a common complication in the neonatal intensive care unit that causes a high mortality of preterm infants and various chronic kidney diseases in adulthood. Preterm infants have immature development of the kidneys at birth. The kidneys continue to develop within a specific time window after birth. However, due to various factors during pregnancy and after birth, preterm infants tend to develop AKI. At present, serum creatinine and urine volume are used for the assessment of kidney injury, and their early sensitivity and specificity have attracted increasing attention. In recent years, various new biomarkers have been identified for early recognition of AKI. This article reviews the features, risk factors, renal function assessment, and prevention/treatment of AKI of preterm infants, in order to provide a reference for improving early diagnosis and treatment of AKI in preterm infants and long-term quality of life.