Nephron number, hypertension, renal disease, and renal failure

Lupus nephritis in Indigenous Australians: a single-centre study

BACKGROUND

The incidence, presentation and outcomes of lupus nephritis (LN) vary with geography, ethnicity, socioeconomic status and gender. There are relatively few data on LN in the non-Caucasian populations in Australia.

AIMS

To describe the clinical presentation, histological features, natural history, and outcomes of a historical cohort of Aboriginal and Torres Strait Islanders people in Far North Queensland with biopsy-proven LN.

METHODS

This is a retrospective observational study, and the study was conducted in Cairns and Hinterland Hospital and Health Service, Queensland, Australia. The study included Aboriginal and Torres Strait Islander patients with biopsy-proven LN treated between 1990 and 2013. The main outcome measures were renal replacement therapy and overall patient survival.

RESULTS

Aboriginal and Torres Strait Islander people represented a substantial proportion (n = 16/40, 40%) of all patients diagnosed with LN during the observation period. The frequency of nephrotic range proteinuria (n = 11/14, 78.5%), estimated glomerular filtration rate <60 mL/min/1.73 m² (n = 6/14, 42.8%) and proliferative LN (n = 13/16, 81.25%) was high at the time of presentation. Despite use of multiple immunosuppressive agents, the overall rate of remission was poor (n = 4/14, 28.5%) and incidence of end-stage kidney disease (n = 4/14, 28.5%) and death (n = 5/16, 31.25%) was high.

CONCLUSIONS

The clinical presentation of LN in Aboriginal and Torres Strait Islanders in Far North Queensland is severe and the response to standard immunosuppressive therapy is unsatisfactory. Larger prospective multi-centre studies are required to better understand ethnic disparities in prognosis and response to immunosuppressive therapy in this specific population.

Quercetin treatment reduces the severity of renal dysplasia in a beta-catenin dependent manner

Renal dysplasia, the major cause of childhood renal failure, is characterized by defective branching morphogenesis and nephrogenesis. Beta-catenin, a transcription factor and cell adhesion molecule, is markedly increased in the nucleus of kidney cells in human renal dysplasia and contributes to its pathogenesis by altering target genes that are essential for kidney development. Quercetin, a naturally occurring flavonoid, reduces nuclear beta-catenin levels and reduces beta-catenin transcriptional activity. In this study, we utilized wild type and dysplastic mouse kidney organ explants to determine if quercetin reduces beta-catenin activity during kidney development and whether it improves the severity of renal dysplasia. In wild type kidney explants, quercetin treatment resulted in abnormal branching morphogenesis and nephrogenesis in a dose dependent manner. In wild type embryonic kidneys, quercetin reduced nuclear beta-catenin expression and decreased expression of beta-catenin target genes Pax2, Six2, and Gdnf, which are essential for kidney development. Our RD^B mouse model of renal dysplasia recapitulates the overexpression of beta-catenin and histopathological changes observed in human renal dysplasia. RD^B kidneys treated with quercetin resulted in improvements in the overall histopathology, tissue organization, ureteric branching morphogenesis, and nephrogenesis. Quercetin treatment also resulted in reduced nuclear beta-catenin and reduced Pax2 expression. These improvements were associated with the proper organization of vimentin, NCAM, and E-cadherin, and a 45% increase in the number of developing and maturing nephrons. Further, our results show that in human renal dysplasia, beta-catenin, vimentin, and e-cadherin also have abnormal expression patterns. Taken together, these data demonstrate that quercetin treatment reduces nuclear beta-catenin and this is associated with improved epithelial organization of developing nephrons, resulting in increased developing nephrons and a partial rescue of renal dysplasia.

Of Mice and Men: The Effect of Maternal Protein Restriction on Offspring's Kidney Health. Are Studies on Rodents Applicable to Chronic Kidney Disease Patients? A Narrative Review

In the almost 30 years that have passed since the postulation of the "Developmental Origins of Health and Disease" theory, it has been clearly demonstrated that a mother's dietary habits during pregnancy have potential consequences for her offspring that go far beyond in utero development. Protein malnutrition during pregnancy, for instance, can cause severe alterations ranging from intrauterine growth retardation to organ damage and increased susceptibility to hypertension, diabetes mellitus, cardiovascular diseases and chronic kidney disease (CKD) later in life both in experimental animals and humans. Conversely, a balanced mild protein restriction in patients affected by CKD has been shown to mitigate the biochemical derangements associated with kidney disease and even slow its progression. The first reports on the management of pregnant CKD women with a moderately protein-restricted plant-based diet appeared in the literature a few years ago. Today, this approach is still being debated, as is the optimal source of protein during gestation in CKD. The aim of this report is to critically review the available literature on the topic, focusing on the similarities and differences between animal and clinical studies.

Deletion of hypoxia-responsive microRNA-210 results in a sex-specific decrease in nephron number

Low nephron number results in an increased risk of developing hypertension and chronic kidney disease. Intrauterine growth restriction is associated with a nephron deficit in humans, and is commonly caused by placental insufficiency, which results in fetal hypoxia. The underlying mechanisms by which hypoxia impacts kidney development are poorly understood. microRNA-210 is the most consistently induced microRNA in hypoxia and is known to promote cell survival in a hypoxic environment. In this study, the role of microRNA-210 in kidney development was evaluated using a global microRNA-210 knockout mouse. A male-specific 35% nephron deficit in microRNA-210 knockout mice was observed. Wnt/β-catenin signaling, a pathway crucial for nephron differentiation, was misregulated in male kidneys with increased expression of the canonical Wnt target lymphoid enhancer binding factor 1. This coincided with increased expression of caspase-8-associated protein 2, a known microRNA-210 target and apoptosis signal transducer. Together, these data are consistent with a sex-specific requirement for microRNA-210 in kidney development.

Exploring the putative interactions between chronic kidney disease and chronic periodontitis

Chronic kidney disease (CKD) and chronic periodontitis (CP) are both common diseases, which are found disproportionately comorbid with each other and have been reported to have a detrimental effect on the progression of each respective disease. They have an overlap in risk factors and both are a source of systemic inflammation along with a wide selection of immunological and non-specific effects that can affect the body over the lifespan of the conditions. Previous studies have investigated the directionality of the relationship between these two diseases; however, there is a lack of literature that has examined how these diseases may be interacting at the localized and systemic level. This review discusses how oral microorganisms have the ability to translocate and have distal effects and provides evidence for microbial involvement in a systemic disease. Furthermore, it summarizes the reported local and systemic effects of CKD and CP and discusses how the interaction of these effects may be responsible for directionality associations reported.

A practical guide to the stereological assessment of glomerular number, size, and cellular composition

The evaluation of a range of measures in the kidneys, such as developmental stage, rate and success, injury, and disease processes, relies on obtaining information on the three-dimensional structure of the renal corpuscles, and in particular the glomerular capillary tufts. To do this in the most accurate, comprehensive, and unbiased manner depends on a knowledge of stereological methods. In this article, we provide a practical guide for researchers on how to quantitate a number of structures in the kidneys, including the estimation of total glomerular number, glomerular capillary length and filtration surface area, and the cellular composition of individual glomeruli. Guidance is also provided on how to apply these methods to kidneys at different sizes and levels of maturity.

Porcine models for studying complications and organ crosstalk in diabetes mellitus

The worldwide prevalence of diabetes mellitus and obesity is rapidly increasing not only in adults but also in children and adolescents. Diabetes is associated with macrovascular complications increasing the risk for cardiovascular disease and stroke, as well as microvascular complications leading to diabetic nephropathy, retinopathy and neuropathy. Animal models are essential for studying disease mechanisms and for developing and testing diagnostic procedures and therapeutic strategies. Rodent models are most widely used but have limitations in translational research. Porcine models have the potential to bridge the gap between basic studies and clinical trials in human patients. This article provides an overview of concepts for the development of porcine models for diabetes and obesity research, with a focus on genetically engineered models. Diabetes-associated ocular, cardiovascular and renal alterations observed in diabetic pig models are summarized and their similarities with complications in diabetic patients are discussed. Systematic multi-organ biobanking of porcine models of diabetes and obesity and molecular profiling of representative tissue samples on different levels, e.g., on the transcriptome, proteome, or metabolome level, is proposed as a strategy for discovering tissue-specific pathomechanisms and their molecular key drivers using systems biology tools. This is exemplified by a recent study providing multi-omics insights into functional changes of the liver in a transgenic pig model for insulin-deficient diabetes mellitus. Collectively, these approaches will provide a better understanding of organ crosstalk in diabetes mellitus and eventually reveal new molecular targets for the prevention, early diagnosis and treatment of diabetes mellitus and its associated complications.

Normal sonographic renal length measurements in an Australian pediatric population

BACKGROUND

Reference charts depicting normal growth are important for the sonographic assessment of the pediatric kidney. Limited charts are available for clinical use in an Australian population.

OBJECTIVE

To retrospectively collate sonographic renal length measurements in a cohort of low-risk Australian children aged newborn to 16 years to produce a reference table and comparison with other published charts.

MATERIALS AND METHODS

We identified consecutive pediatric patients who were at low risk for renal disease and had renal lengths measured. After exclusions, we included 941 renal lengths (male 490, female 451). We used linear regression to estimate the relationship of renal length with age, gender and side. We calculated percentile values of renal length according to age categories.

RESULTS

No statistically significant differences in mean renal length were observed between males and females, or for left and right kidneys. We tabulated reference data and provide them in a reference chart (1-, 2.5-, 5-, 10-, 50-, 90-, 97.5- and 99-percentiles).

CONCLUSION

We calculated new reference ranges for pediatric renal length using a larger cohort than previously published, from a population with diverse ethnicity.

Resilience to acute kidney injury in offspring of maternal protein restriction

Protein restriction (PR) during pregnancy induces morphofunctional alterations related to deficient nephrogenesis. We studied the renal functional and morphological significance of PR during pregnancy and/or lactation in adult male rat offspring and the repercussions on acute kidney injury (AKI) severity. Female rats were randomly assigned to the following groups: control diet during pregnancy and lactation (CC), control diet during pregnancy and PR diet during lactation (CR), PR during pregnancy and control diet during lactation (RC), and PR during pregnancy and lactation (RR). Three months after birth, at least 12 male offspring of each group randomly underwent either bilateral renal ischemia for 45 min [ischemia-reperfusion (IR)] or sham surgery. Thus, eight groups were studied 24 h after reperfusion: CC, CC + IR, CR, CR + IR, RC, RC + IR, RR, and RR + IR. Under basal conditions, the CR, RC, and RR groups exhibited a significant reduction in nephron number that was associated with a reduction in renal blood flow. Glomerular hyperfiltration was present as a compensatory mechanism to maintain normal renal function. mRNA levels of several vasoactive, antioxidant, and anti-inflammatory molecules were decreased. After IR, renal function was similarly reduced in all of the studied groups. Although all of the offspring from maternal PR exhibited renal injury, the magnitude was lower in the RC and RR groups, which were associated with faster renal blood flow recovery, differential vasoactive factors, and hypoxia-inducible factor-1α signaling. Our results show that the offspring from maternal PR are resilient to AKI induced by IR that was associated with reduced tubular injury and a differential hemodynamic response.

Histology Atlas of the Developing Mouse Urinary System With Emphasis on Prenatal Days E10.5-E18.5

Congenital abnormalities of the urinary tract are some of the most common human developmental abnormalities. Several genetically engineered mouse models have been developed to mimic these abnormalities and aim to better understand the molecular mechanisms of disease. This atlas has been developed as an aid to pathologists and other biomedical scientists for identification of abnormalities in the developing murine urinary tract by cataloguing normal structures at each stage of development. Hematoxylin and eosin- and immunohistochemical-stained sections are provided, with a focus on E10.5-E18.5, as well as a brief discussion of postnatal events in urinary tract development. A section on abnormalities in the development of the urinary tract is also provided, and molecular mechanisms are presented as supplementary material. Additionally, overviews of the 2 key processes of kidney development, branching morphogenesis and nephrogenesis, are provided to aid in the understanding of the complex organogenesis of the kidney. One of the key findings of this atlas is the histological identification of the ureteric bud at E10.5, as previous literature has provided conflicting reports on the initial point of budding. Furthermore, attention is paid to points where murine development is significantly distinct from human development, namely, in the cessation of nephrogenesis.

Risk of hypertension following perinatal adversity: IUGR and prematurity

Consistent with the paradigm shifting observations of David Barker and colleagues that revealed a powerful relationship between decreased weight through 2 years of age and adult disease, intrauterine growth restriction (IUGR) and preterm birth are independent risk factors for the development of subsequent hypertension. Animal models have been indispensable in defining the mechanisms responsible for these associations and the potential targets for therapeutic intervention. Among the modifiable risk factors, micronutrient deficiency, physical immobility, exaggerated stress hormone exposure and deficient trophic hormone production are leading candidates for targeted therapies. With the strong inverse relationship seen between gestational age at delivery and the risk of hypertension in adulthood trumping all other major cardiovascular risk factors, improvements in neonatal care are required. Unfortunately, therapeutic breakthroughs have not kept pace with rapidly improving perinatal survival, and groundbreaking bench-to-bedside studies are urgently needed to mitigate and ultimately prevent the tsunami of prematurity-related adult cardiovascular disease that may be on the horizon. This review highlights our current understanding of the developmental origins of hypertension and draws attention to the importance of increasing the availability of lactation consultants, nutritionists, pharmacists and physical therapists as critical allies in the battle that IUGR or premature infants are waging not just for survival but also for their future cardiometabolic health.

Combined Antioxidant and Glucocorticoid Therapy for Safer Treatment of Preterm Birth

Ante- and postnatal glucocorticoid therapy reduces morbidity and mortality in the preterm infant, and it is therefore one of the best examples of the successful translation of basic experimental science into human clinical practice. However, accruing evidence derived from human clinical studies and from experimental studies in animal models raise serious concerns about potential long-term adverse effects of treatment on growth and neurological and cardiovascular function in the offspring. This review explores whether combined antioxidant and glucocorticoid therapy may be safer than glucocorticoid therapy alone for the treatment of preterm birth.

Maternal-Infant Supplementation with Small-Quantity Lipid-Based Nutrient Supplements Does Not Affect Child Blood Pressure at 4-6 Y in Ghana: Follow-up of a Randomized Trial

BACKGROUND

In the International Lipid-Based Nutrient Supplements (iLiNS)-DYAD-Ghana trial, prenatal small-quantity lipid-based nutrient supplements (LNSs) had a positive effect on birth weight. Birth weight may be inversely related to blood pressure (BP) later in life.

OBJECTIVES

We examined the effect of the intervention on BP at 4-6 y of age, and maternal and child factors related to BP.

METHODS

The iLiNS-DYAD-Ghana study was a partially double-blind, randomized controlled trial which assigned women (n = 1320) ≤20 weeks of gestation to daily supplementation with: 1) iron and folic acid during pregnancy and 200 mg Ca for 6 mo postpartum , 2) multiple micronutrients during pregnancy and postpartum, or 3) LNSs during pregnancy and postpartum plus LNSs for infants from 6 to 18 mo of age. At 4-6 y of age (n = 858, 70% of live births), we compared BP, a secondary outcome, between non-LNS and LNS groups and examined whether BP was related to several factors including maternal BP, child weight-for-age z score (WAZ), and physical activity.

RESULTS

Non-LNS and LNS groups did not differ in systolic (99.2 ± 0.4 compared with 98.5 ± 0.6 mm Hg; P = 0.317) or diastolic (60.1 ± 0.3 compared with 60.0 ± 0.4 mm Hg; P = 0.805) BP, or prevalence of high BP (systolic or diastolic BP ≥90th percentile of the US National Heart, Lung, and Blood Institute reference: 31% compared with 28%; P = 0.251). BP at 4-6 y of age was positively related to birth weight; this relation was largely mediated through concurrent WAZ in a path model. Concurrent WAZ and maternal BP were the factors most strongly related to child BP.

CONCLUSIONS

Despite greater birth weight in the LNS group, there was no intervention group difference in BP at 4-6 y. In this preschool population at high risk of adult hypertension based on BP at 4-6 y, high maternal BP and child WAZ were key factors related to BP. This trial was registered at clinicaltrials.gov as NCT00970866.

Lin28 and let-7 regulate the timing of cessation of murine nephrogenesis

In humans and in mice the formation of nephrons during embryonic development reaches completion near the end of gestation, after which no new nephrons are formed. The final nephron complement can vary 10-fold, with reduced nephron number predisposing individuals to hypertension, renal, and cardiovascular diseases in later life. While the heterochronic genes lin28 and let-7 are well-established regulators of developmental timing in invertebrates, their role in mammalian organogenesis is not fully understood. Here we report that the Lin28b/let-7 axis controls the duration of kidney development in mice. Suppression of let-7 miRNAs, directly or via the transient overexpression of LIN28B, can prolong nephrogenesis and enhance kidney function potentially via upregulation of the Igf2/H19 locus. In contrast, kidney-specific loss of Lin28b impairs renal development. Our study reveals mechanisms regulating persistence of nephrogenic mesenchyme and provides a rationale for therapies aimed at increasing nephron mass.

Nephrogenesis ceases after postnatal day 2 in the mouse or after the 36th week of gestation in humans, but how this is regulated is unclear. Here, the authors identify a role for the RNA-binding protein Lin28 and suppression of let-7 microRNA in regulating the duration of nephrogenesis.

Impact of prenatal and postnatal maternal environment on nephron endowment, renal function and blood pressure in the Lewis polycystic kidney rat

Maternal insufficiency during fetal development can have long-lasting effects on the offspring, most notably on nephron endowment. In polycystic kidney disease (PKD), variability in severity of disease is observed and maternal environment may be a modifying factor. In this study, we first established that in a rodent model of PKD, the Lewis polycystic kidney (LPK) rat's nephron numbers are 25% lower compared with wildtype animals. We then investigated the effects of prenatal and postnatal maternal environment on phenotype and nephron number. LPK pups born from and raised by homozygous LPK dams (control) were compared with LPK pups cross-fostered onto heterozygous LPK dams to improve postnatal environment; with LPK pups born from and raised by heterozygous LPK dams to improve both prenatal and postnatal environment and with LPK pups born from and raised by Wistar Kyoto-LPK heterozygous dams to improve both prenatal and postnatal environment on a different genetic background. Improvement in both prenatal and postnatal environment improved postnatal growth, renal function and reduced blood pressure, most notably in animals with different genetic background. Animals with improved postnatal environment only showed improved growth and blood pressure, but to a lesser extent. All intervention groups showed increased nephron number compared with control LPK. In summary, prenatal and postnatal environment had significant effect in delaying progression and reducing severity of PKD, including nephron endowment.

Impacts of Diabetes and an SGLT2 Inhibitor on the Glomerular Number and Volume in db/db Mice, as Estimated by Synchrotron Radiation Micro-CT at SPring-8

BACKGROUND

Recent large-scale clinical studies demonstrate that sodium-glucose cotransporter 2 (SGLT2) inhibitors protect the diabetic kidney. However, clinical and animal studies have not shown the changes of the total glomeruli in the whole kidney treated with SGLT2 inhibitors.

METHODS

We performed computed tomography (CT) imaging on mice using synchrotron radiation to investigate the impact of luseogliflozin, a SGLT2 inhibitor, on the number and volume of glomeruli in the whole kidney.

FINDINGS

We did not observe a significant difference in the total glomerular number (Nglom) among mice. Luseogliflozin redistributed the number of glomeruli in different regions, accompanied by the normalization of diabetes-augmented renal volume (Vkidney). Diabetic db/db mice had a larger glomerular volume in the mid-cortex than did control db/m mice, and luseogliflozin increased the glomerular volume in all renal cortical zones of the whole kidney in db/db mice. According to the multivariate regression analysis, hemoglobin A1c level was the most relevant determinant of Vkidney, not Nglom or mean glomerular volume (Vglom), indicating that hyperglycemia induced renal (tubular) hypertrophy, but not glomerular enlargement. Luseogliflozin increased hypoxia in the juxtamedullary region, sustained upregulated renal renin expression and plasma renin activity, and failed to decrease albuminuria by downregulating megalin in db/db mice.

INTERPRETATION

Based on our findings, SGLT2 inhibitors may alter glomerular distribution and size in addition to their glucose-lowering effects, presumably by affecting oxygen metabolism and humoral factors. FUND: Funding for this research was provided by The Japan Society for the Promotion of Science, the Japan Diabetes Foundation, and Asahikawa Medical University.

Serum creatinine during physiological perinatal dehydration may estimate individual nephron endowment

It is well known that the nephron endowment of healthy subjects is highly variable and that individual nephron mass has potentially important implications both in health and disease. However, nephron count is technically impossible in living subjects. Based on the observation of an increase in serum creatinine (sCr) in otherwise healthy newborns with solitary kidney during the physiological perinatal dehydration, we hypothesized that perinatal sCr might be helpful in identifying healthy subjects with a reduced nephron mass. In the framework of a study on blood pressure in babies (NeoNeph), sCr of normal Caucasian neonates was determined 48-96 h after birth and their association with a family history of arterial hypertension (AH) was analyzed. SCr was determined in 182 normal newborns (90 males) at a mean of 61 ± 8 h after birth (range 46-82). Newborns with paternal AH had a higher mean sCr (0.97 + 0.28 mg/dL) then newborns without paternal AH (0.73 + 0.28 mg/dL; p = 0.006). No differences in mean sCr were found in relation with mother or grandparent's history of AH.

CONCLUSION

The association between parental AH and high sCr during perinatal dehydration supports the hypothesis that the latter is a promising tool for identifying normal subjects with a reduced nephron mass with potential important implications in prevention and in understanding the individual outcome of renal and extrarenal diseases (including AH). What is Known: • Nephron endowment of healthy subjects is highly variable and individual nephron mass has potentially important implications both in health and disease however nephron count is not feasible in living subjects. What is New: • Serum creatinine during perinatal dehydration is a possible biomarker for identifying normal subjects with a reduced nephron mass.

Immune cells and inflammation in AKI to CKD progression

Acute kidney injury (AKI) is a common clinical state resulting from pathogenic conditions such as ischemic and toxic insults. The pathophysiology of AKI shares common pathogenic denominators including cell death/injury, inflammation, and fibrosis, regardless of the initiating insults. Recent clinical studies have shown that a single episode of AKI can lead to subsequent chronic kidney disease (CKD). Although the involvement of multiple types of cells in the pathophysiology of AKI is becoming increasingly clear, the precise mechanisms for this "AKI to CKD progression" are still unknown, and no drug has been shown to halt this progression. An increasing number of epidemiological studies have also revealed that the presence of aging greatly increases the risk of AKI to CKD progression, and chronic inflammation is increasingly recognized as an important determinant factor for this progression. In this review article, we first describe the current understanding of the pathophysiology of AKI to CKD progression based on multiple types of cells. In particular, we will highlight the recent findings in regard to the mechanisms for chronic inflammation after AKI. Subsequently, we will focus on the mechanisms responsible for the increased risk of AKI to CKD progression in the elderly. Finally, we highlight our recent finding of age-dependent tertiary lymphoid tissue formation and its roles in AKI to CKD progression and speculate on the potential therapeutic opportunities that come from targeting aberrant inflammation after AKI.

Strategies to reduce non-communicable diseases in the offspring: negative and positive in utero programming

Non-communicable diseases (NCDs) are a major problem as they are the leading cause of death and represent a substantial economic cost. The 'Developmental Origins of Health and Disease Hypothesis' proposes that adverse stimuli at different life stages can increase the predisposition to these diseases. In fact, adverse in utero programming is a major origin of these diseases due to the high malleability of embryonic development. This review provides a comprehensive analysis of the scientific literature on in utero programming and NCDs highlighting potential medical strategies to prevent these diseases based upon this programming. We fully address the concept and mechanisms involved in this programming (anatomical disruptions, epigenetic modifications and microbiota alterations). We also examine the negative role of in utero programming on the increased predisposition of NCDs in the offspring, which introduces the passive medical approach that consists of avoiding adverse stimuli including an unhealthy diet and environmental chemicals. Finally, we extensively discuss active medical approaches that target the causes of NCDs and have the potential to significantly and rapidly reduce the incidence of NCDs. These approaches can be classified as direct in utero programming modifications and personalized lifestyle pregnancy programs; they could potentially provide transgenerational NCDs protection. Active strategies against NCDs constitute a promising tool for the reduction in NCDs.

Antenatal exposure to nonsteroidal anti-inflammatory drugs and risk of neonatal hypertension

Nonsteroidal anti-inflammatory drugs (NSAIDs) are used as tocolytics, which are medications that suppress uterine contractions for preterm birth prevention. Their effect on cerebral/systemic vascular beds poses the question of whether antenatal NSAID exposure is associated with neonatal hypertension. We performed a retrospective case-control study in a tertiary neonatal intensive care unit, including 40 hypertension cases (hospitalized neonates ≥ 35 weeks with systolic BP > 100 mm Hg on three consecutive days) compared to 134 controls matched by gestational age at delivery, plurality, and delivery date. Cases and controls were compared by antenatal NSAID exposure, other common tocolytics, and maternal/neonatal characteristics and complications. Multivariable logistic regression was used to estimate the odds of hypertension among those with prenatal exposure to NSAIDs versus those without exposure. Newborns with hypertension had a lower gestational age at delivery and increased incidence of neonatal complications, including respiratory distress syndrome, bronchopulmonary dysplasia, surfactant administration, longer duration of ventilation, and history of umbilical artery catheterization. Days of indomethacin exposure were positively associated with greater odds of neonatal hypertension (OR 1.17 [1.00 to 1.38], P = 0.055), even after adjustment for other factors associated with neonatal hypertension. Newborns with hypertension were less likely to have been exposed to calcium channel blockers as a tocolytic. The results of our study suggest an association between prenatal exposure to nonsteroidal anti-inflammatory drugs and neonatal hypertension. Furthermore, our data suggest that prenatal calcium channel blocker exposure may protect against the development of neonatal hypertension. Future multicenter studies are needed to understand the risks of tocolytics and subsequent consequences in preterm infants.

APOL1 risk variants and kidney disease: what we know so far

There are striking differences in chronic kidney disease between Caucasians and African descendants. It was widely accepted that this occurred due to socioeconomic factors, but recent studies show that apolipoprotein L-1 (APOL1) gene variants are strongly associated with focal segmental glomerulosclerosis, HIV-associated nephropathy, hypertensive nephrosclerosis, and lupus nephritis in the African American population. These variants made their way to South America trough intercontinental slave traffic and conferred an evolutionary advantage to the carries by protecting against forms of trypanosomiasis, but at the expense of an increased risk of kidney disease. The effect of the variants does not seem to be related to their serum concentration, but rather to local action on the podocytes. Risk variants are also important in renal transplantation, since grafts from donors with risk variants present worse survival.

Association Between Newborn Metabolic Profiles and Pediatric Kidney Disease

INTRODUCTION

Metabolomics offers considerable promise in early disease detection. We set out to test the hypothesis that routine newborn metabolic profiles at birth, obtained through screening for inborn errors of metabolism, would be associated with kidney disease and add incremental information to known clinical risk factors.

METHODS

We conducted a population-level cohort study in Ontario, Canada, using metabolic profiles from 1,288,905 newborns from 2006 to 2015. The primary outcome was chronic kidney disease (CKD) or dialysis. Individual metabolites and their ratio combinations were examined by logistic regression after adjustment for established risk factors for kidney disease and incremental risk prediction measured.

RESULTS

CKD occurred in 2086 (0.16%, median time 612 days) and dialysis in 641 (0.05%, median time 99 days) infants and children. Individual metabolites consisted of amino acids, acylcarnitines, markers of fatty acid oxidation, and others. Base models incorporating clinical risk factors only provided c-statistics of 0.61 for CKD and 0.70 for dialysis. The addition of identified metabolites to risk prediciton models resulted in significant incremental improvement in the performance of both models (CKD model: c-statistic 0.66 NRI 0.36 IDI 0.04, dialysis model: c-statistic 0.77 NRI 0.57 IDI 0.09). This was consistent after internal validation using bootstrapping and a sensitivity analysis excluding outcomes within the first 30 days.

CONCLUSION

Routinely collected screening metabolites at birth are associated with CKD and the need for dialytic therapies in infants and children, and add incremental information to traditional clinical risk factors.

Association of preterm birth and small for gestational age with metabolic outcomes in children and adolescents: A population-based cohort study from Taiwan

BACKGROUND

Previous studies have identified preterm birth and/or small for gestational age (SGA) as risk factors for features of the metabolic syndrome, including high blood pressure, insulin sensitivity and atherosclerosis, occurring later in life, with controversial results. We conducted this population-based cohort study to investigate metabolic outcomes in those with former preterm birth and/or SGA status in Taiwan.

METHODS

Data were obtained from Taiwan's universal National Health Insurance Research Database. From 1996 to 2004, 37,119 preterm infants, 3386 SGA infants, and 162,020 matched controls were included. We investigated the risk of the metabolic disease, including hypertension, diabetes, and hyperlipidemia, which had been recorded by the end of 2008.

RESULTS

The preterm and SGA cohort, combined into one, had a significantly increased risk of developing metabolic disorders when compared with the comparison cohort (HR = 2.46, 95% CI = 2.02-3.01). We observed that children with former preterm and SGA status in Taiwan had a higher risk of developing hypertension (HR = 3.24, 95% CI = 1.58-6.67), Type 1 diabetes mellitus (HR = 1.80, 95% CI = 1.05-3.07), Type 2 diabetes mellitus (HR = 2.49, 95% CI = 1.98-3.14), and hyperlipidemia (HR = 2.14, 95% CI = 1.29-3.52).

CONCLUSION

Our study revealed the risk of metabolic disease in those with preterm birth and/or SGA. Further studies with a longer duration of follow-up are required to confirm if there is a tendency for the metabolic syndrome to develop in this study cohort.

Conserved and Divergent Features of Human and Mouse Kidney Organogenesis

Human kidney function is underpinned by approximately 1,000,000 nephrons, although the number varies substantially, and low nephron number is linked to disease. Human kidney development initiates around 4 weeks of gestation and ends around 34-37 weeks of gestation. Over this period, a reiterative inductive process establishes the nephron complement. Studies have provided insightful anatomic descriptions of human kidney development, but the limited histologic views are not readily accessible to a broad audience. In this first paper in a series providing comprehensive insight into human kidney formation, we examined human kidney development in 135 anonymously donated human kidney specimens. We documented kidney development at a macroscopic and cellular level through histologic analysis, RNA in situ hybridization, immunofluorescence studies, and transcriptional profiling, contrasting human development (4-23 weeks) with mouse development at selected stages (embryonic day 15.5 and postnatal day 2). The high-resolution histologic interactive atlas of human kidney organogenesis generated can be viewed at the GUDMAP database (www.gudmap.org) together with three-dimensional reconstructions of key components of the data herein. At the anatomic level, human and mouse kidney development differ in timing, scale, and global features such as lobe formation and progenitor niche organization. The data also highlight differences in molecular and cellular features, including the expression and cellular distribution of anchor gene markers used to identify key cell types in mouse kidney studies. These data will facilitate and inform in vitro efforts to generate human kidney structures and comparative functional analyses across mammalian species.

Tick-Tock Chimes the Kidney Clock - from Biology of Renal Ageing to Clinical Applications

Ageing of the kidney is a multi-dimensional process that occurs simultaneously at the molecular, cellular, histological, anatomical and physiological level. Nephron number and renal cortical volume decline, renal tubules become atrophic and glomeruli become sclerotic with age. These structural changes are accompanied by a decline in glomerular filtration rate, decreased sodium reabsorption and potassium excretion, reduced urinary concentrating capacity and alterations in the endocrine activity of the kidney. However, the pace of progression of these changes is not identical in everyone - individuals of the same age and seemingly similar clinical profile often exhibit stark differences in the age-related decline in renal health. Thus, chronological age poorly reflects the time-dependent changes that occur in the kidney. An ideal measure of renal vitality is biological kidney age - a measure of the age-related changes in physiological function. Replacing chronological age with biological age could provide numerous clinical benefits including improved prognostic accuracy in renal transplantation, better stratification of risk and identification of those who are on a fast trajectory to an age-related drop in kidney health.

Mild Salt-Sensitive Hypertension in Genetically Determined Low Nephron Number is Associated with Chloride but Not Sodium Retention

BACKGROUND/AIMS

One potential pathomechanism how low nephron number leads to hypertension in later life is altered salt handling. We therefore evaluated changes in electrolyte and water content in wildtype (wt) and GDNF+/- mice with a 30% reduction of nephron number.

METHODS

32 GDNF+/- and 36 wt mice were fed with low salt (LSD, 0.03%, normal drinking water) or high salt (HSD, 4%, 0.9% drinking water) diet for 4 weeks. Blood pressure was continuously measured by telemetry in a subgroup. At the end of the experiment and after standardized ashing processes electrolyte- and water contents of the skin and the total body were determined.

RESULTS

We found higher blood pressure in high salt treated GDNF+/-compared to wt mice. Of interest, we could not confirm an increase in total-body sodium as predicted by prevailing explanations, but found increased total body and skin chloride that interestingly correlated with relative kidney weight.

CONCLUSION

We hereby firstly report significant total body and skin chloride retention in salt sensitive hypertension of GDNF+/-mice with genetically determined lower nephron number. Thus, in contrast to the prevailing opinion our data argue for the involvement of non-volume related mechanisms.

Exposure to famine in early life and chronic kidney diseases in adulthood

Objective

Chronic kidney disease (CKD) is an increasing contributor to the global disease burden. Previous findings indicated that exposure to famine in early life was associated with various metabolic diseases and urinary protein levels. We aimed to assess whether the exposure to China’s Great Famine 1959–1962 during fetal or childhood period was associated with glomerular filtration rate (GFR) and risk of CKD (eGFR<60 mL/min per 1.73 m²) in adulthood.

Materials and methods

SPECT-China was a population-based observational study in 2014–2015. Totally, 5124 women were included from SPECT-China study. Based on the birth year, they were divided into fetal-exposed (1959–1962), childhood-exposed (1949–1958), adolescence/young adult-exposed (1921–1948), and non-exposed (1963–1974, reference). The estimated glomerular filtration rate (eGFR) was calculated according to the Chronic Kidney Disease Epidemiology Collaboration equation. CKD was defined as eGFR less than 60 mL/min per 1.73 m².

Results

Compared with the non-exposed, fetal exposure to famine was significantly associated with lower eGFR (B −1.47, 95%CI −2.81, −1.13) and greater risk of having CKD (OR 2.85, 95%CI 1.25, 6.50) in the crude model adjusting age. Further adjustments for demographic variables, body mass index, diabetes, and blood pressure did not qualitatively change the association (eGFR B −1.35, 95%CI −2.67, −0.04; CKD OR 2.42, 95%CI 1.05, 5.58). This association was not found in childhood-exposed and adolescence/young adult-exposed individuals.

Conclusions

Prenatal exposure to famine may have long-term effects on declined GFR and the development of CKD in humans. thus, fetal stage may be an important time window to prevent CKD in later life.

Assessment of Fetal Kidney Growth and Birth Weight in an Indigenous Australian Cohort

Introduction: Indigenous Australians experience higher rates of renal disease and hypertension than non-Indigenous Australians. Low birth weight is recognized as a contributing factor in chronic disease and has been shown to increase the risk of renal failure in adulthood. A smaller kidney volume with fewer nephrons places an individual at risk of hypertension and renal failure. Indigenous Australians have fewer nephrons than non-Indigenous Australians. In this study, intrauterine fetal and kidney growth were evaluated in 174 Indigenous Australian babies throughout gestation in order to record and evaluate fetal growth and kidney size, within a population that is at high risk for chronic illness. Methods: Pregnant women that identified as Indigenous, or non-Indigenous women that were pregnant with a partner who identified as an Indigenous Australian were eligible to participate. Maternal history, smoking status, blood and urine samples and fetal ultrasounds were collected throughout pregnancy. Fetal kidney measurements were collected using ultrasound. Statistical analysis was performed using the Stata 14.1 software package. Results: 15.2% of babies were born prematurely. 44% of the mothers reported smoking in pregnancy. The median birth weight of this cohort was 3,240 g. Male fetuses had higher kidney to body weight ratios than female fetuses (P = 0.02). The birth weights of term neonates whose mothers smoked during pregnancy were lower (327 g, P < 0.001) than the birth weights of term babies from non-smoking mothers. The kidney volumes of babies whose mothers smoked were also smaller (P = 0.02), but were in proportion to body weight. Conclusion: In this cohort of Indigenous women smoking was associated with both increased number of preterm births and with a reduction in birth weights, even of term infants. Since kidney volume is a surrogate measure of nephron number and nephrogenesis is complete at birth, babies whose mothers smoked during pregnancy must have fewer nephrons than those from non-smoking mothers. Previous studies have shown that glomerular filtration rate is not related to birth weight, thus infants with smaller kidney volumes are hyperfiltering from birth and therefore are likely to be more susceptible to early onset renal disease in later life.

The Epigenetic Machinery in Vascular Dysfunction and Hypertension

Hypertension (HT) is among the major components of the metabolic syndrome, i.e., obesity, dyslipidemia, and hyperglycemia/insulin resistance. It represents a significant health problem with foremost risks for chronic cardiovascular disease and a significant cause of morbidity and mortality worldwide. Therefore, it is not surprising that this disorder constitutes a serious public health concern. Although multiple studies have stressed the multifactorial nature of HT, the pathogenesis remains largely unknown. However, if we want to reduce the global prevalence of HT, restrain the number of deaths (currently 9.4 million/year in the world), and alleviate the socio-economic burden, a deeper insight into the mechanisms is urgently needed in order to define new meaningful therapeutic targets. Recently, the role of epigenetics in the development of various complex diseases has attracted much attention. In the present review, we provide a critical update on the available literature and ongoing research regarding the epigenetic modifications of genes involved in several pathways of elevated blood pressure, especially those linked to the vascular epithelium. This review also focuses on the role of microRNA (miRNA) in the regulation of gene expression associated with HT and of fetal programming mediating susceptibility to HT in adulthood.

Development of the Human Fetal Kidney from Mid to Late Gestation in Male and Female Infants

Background

During normal human kidney development, nephrogenesis (the formation of nephrons) is complete by term birth, with the majority of nephrons formed late in gestation. The aim of this study was to morphologically examine nephrogenesis in fetal human kidneys from 20 to 41 weeks of gestation.

Methods

Kidney samples were obtained at autopsy from 71 infants that died acutely in utero or within 24 h after birth. Using image analysis, nephrogenic zone width, the number of glomerular generations, renal corpuscle cross-sectional area and the cellular composition of glomeruli were examined. Kidneys from female and male infants were analysed separately.

Findings

The number of glomerular generations formed within the fetal kidneys was directly proportional to gestational age, body weight and kidney weight, with variability between individuals in the ultimate number of generations (8 to 12) and in the timing of the cessation of nephrogenesis (still ongoing at 37 weeks gestation in one infant). There was a slight but significant (r² = 0.30, P = 0.001) increase in renal corpuscle cross-sectional area from mid gestation to term in females, but this was not evident in males. The proportions of podocytes, endothelial and non-epithelial cells within mature glomeruli were stable throughout gestation.

Interpretation

These findings highlight spatial and temporal variability in nephrogenesis in the developing human kidney, whereas the relative cellular composition of glomeruli does not appear to be influenced by gestational age.

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There is spatial and temporal variability in nephrogenesis in the developing human kidney.

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The relative cellular composition of mature glomeruli does not appear to be influenced by gestational age.

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There is apparent sexual dimorphism in the growth of glomeruli during late gestation.

The number of glomeruli (filtering units of the kidneys) you are born with directly influences your life-long kidney health, therefore it is important to understand how they are formed. Between mid-pregnancy and term, there was variability between individuals in relation to the number of layers of glomeruli formed in the developing kidney, and variation in the timing of when they stopped being formed. In fully-formed glomeruli, the proportion of the different cell types in glomeruli remained constant within the developing kidneys throughout pregnancy. Female infants, but not males, exhibited an increase in the size of glomeruli from mid-pregnancy to term.

Birth weight influences the kidney size and function of Bangladeshi children

Early-life conditions influence organ growth patterns and their functions, as well as subsequent risk for non-communicable chronic diseases in later life. A limited number of studies have determined that in Bangladesh, kidney size relates to its function among children as a consequence of the maternal and postnatal conditions. The present study objectives were to determine early-life conditions in relation to childhood kidney size and to compare their influences on kidney function. The study was embedded in a population-based prospective cohort of 1067 full-term singleton live births followed from fetal life onward. Kidney volume was measured by ultrasound in children at the age of 4.5 years (range 45-64 months), and the estimated glomerular filtration rate (eGFR) was assessed at the age of 9 years (range 96-116 months). The mean (s.d.) kidney volume of children at 4.5 years was 64.2 (11.3) cm3, with a significant mean difference observed between low birth weight and normal birth weight children (P<0.001). The multivariable model showed, changes in status from low birth weight to normal birth weight children, with kidney volume increases of 2.92 cm3/m2, after adjusting for the child's age, sex, maternal age and early pregnancy body mass index, and socio-economic index variables. One-unit change in kidney volume (cm3/m2) improved the eGFR to 0.18 ml/min/1.73 m2. The eGFR in low birth weight children was 5.44 ml/min/1.73 m2 less than that in normal birth weight children after adjustments. Low birth weight leads to adverse effects on kidney size and function in children.

Troy/TNFRSF19 marks epithelial progenitor cells during mouse kidney development that continue to contribute to turnover in adult kidney

During kidney development, progressively committed progenitor cells give rise to the distinct segments of the nephron, the functional unit of the kidney. Similar segment-committed progenitor cells are thought to be involved in the homeostasis of adult kidney. However, markers for most segment-committed progenitor cells remain to be identified. Here, we evaluate Troy/TNFRSF19 as a segment-committed nephron progenitor cell marker. Troy is expressed in the ureteric bud during embryonic development. During postnatal nephrogenesis, Troy⁺ cells are present in the cortex and papilla and display an immature tubular phenotype. Tracing of Troy⁺ cells during nephrogenesis demonstrates that Troy⁺ cells clonally give rise to tubular structures that persist for up to 2 y after induction. Troy⁺ cells have a 40-fold higher capacity than Troy^- cells to form organoids, which is considered a stem cell property in vitro. In the adult kidney, Troy⁺ cells are present in the papilla and these cells continue to contribute to collecting duct formation during homeostasis. The number of Troy-derived cells increases after folic acid-induced injury. Our data show that Troy marks a renal stem/progenitor cell population in the developing kidney that in adult kidney contributes to homeostasis, predominantly of the collecting duct, and regeneration.

Haploinsufficiency for the Six2 gene increases nephron progenitor proliferation promoting branching and nephron number

The regulation of final nephron number in the kidney is poorly understood. Cessation of nephron formation occurs when the self-renewing nephron progenitor population commits to differentiation. Transcription factors within this progenitor population, such as SIX2, are assumed to control expression of genes promoting self-renewal such that homozygous Six2 deletion results in premature commitment and an early halt to kidney development. In contrast, Six2 heterozygotes were assumed to be unaffected. Using quantitative morphometry, we found a paradoxical 18% increase in ureteric branching and final nephron number in Six2 heterozygotes, despite evidence for reduced levels of SIX2 protein and transcript. This was accompanied by a clear shift in nephron progenitor identity with a distinct subset of downregulated progenitor genes such as Cited1 and Meox1 while other genes were unaffected. The net result was an increase in nephron progenitor proliferation, as assessed by elevated EdU (5-ethynyl-2'-deoxyuridine) labeling, an increase in MYC protein, and transcriptional upregulation of MYC target genes. Heterozygosity for Six2 on an Fgf20-/- background resulted in premature differentiation of the progenitor population, confirming that progenitor regulation is compromised in Six2 heterozygotes. Overall, our studies reveal a unique dose response of nephron progenitors to the level of SIX2 protein in which the role of SIX2 in progenitor proliferation versus self-renewal is separable.

Hypoxia-inducible factor prolyl-4-hydroxylation in FOXD1 lineage cells is essential for normal kidney development

Hypoxia in the embryo is a frequent cause of intra-uterine growth retardation, low birth weight, and multiple organ defects. In the kidney, this can lead to low nephron endowment, predisposing to chronic kidney disease and arterial hypertension. A key component in cellular adaptation to hypoxia is the hypoxia-inducible factor pathway, which is regulated by prolyl-4-hydroxylase domain (PHD) dioxygenases PHD1, PHD2, and PHD3. In the adult kidney, PHD oxygen sensors are differentially expressed in a cell type-dependent manner and control the production of erythropoietin in interstitial cells. However, the role of interstitial cell PHDs in renal development has not been examined. Here we used a genetic approach in mice to interrogate PHD function in FOXD1-expressing stroma during nephrogenesis. We demonstrate that PHD2 and PHD3 are essential for normal kidney development as the combined inactivation of stromal PHD2 and PHD3 resulted in renal failure that was associated with reduced kidney size, decreased numbers of glomeruli, and abnormal postnatal nephron formation. In contrast, nephrogenesis was normal in animals with individual PHD inactivation. We furthermore demonstrate that the defect in nephron formation in PHD2/PHD3 double mutants required intact hypoxia-inducible factor-2 signaling and was dependent on the extent of stromal hypoxia-inducible factor activation. Thus, hypoxia-inducible factor prolyl-4-hydroxylation in renal interstitial cells is critical for normal nephron formation.

New insights on glomerular hyperfiltration: a Japanese autopsy study

It has been suggested that low nephron number contributes to glomerular hypertension and hyperperfusion injury in progressive chronic kidney disease (CKD). The incidence of CKD in Japan is among the highest in the world, but the reasons remain unclear. We estimated total nephron (glomerular) number (NglomTOTAL) as well as numbers of nonsclerosed (NglomNSG) and globally sclerosed glomeruli (NglomGSG), and the mean volume of nonsclerosed glomeruli (VglomNSG) in Japanese normotensive, hypertensive, and CKD subjects and investigated associations between these parameters and estimated glomerular filtration rate (eGFR). Autopsy kidneys from age-matched Japanese men (9 normotensives, 9 hypertensives, 9 CKD) had nephron number and VglomNSG estimated using disector/fractionator stereology. Subject eGFR, single-nephron eGFR (SNeGFR), and the ratio SNeGFR/VglomNSG were calculated. NglomNSG in Japanese with hypertension (392,108 ± 87,605; P < 0.001) and CKD (268,043 ± 106,968; P < 0.001) was less than in normotensives (640,399 ± 160,016). eGFR was directly correlated with NglomNSG (r = 0.70, P < 0.001) and inversely correlated with VglomNSG (r = -0.53, P < 0.01). SNeGFR was higher in hypertensives than normotensives (P = 0.03), but was similar in normotensives and CKD, while the ratio SNeGFR/VglomNSG was similar in normotensives and hypertensives but markedly reduced in CKD. Nephron number in Japanese with hypertension or CKD was low. This results in a higher SNeGFR in hypertensives compared with normotensive and CKD subjects, but lowered SNeGFR/VglomNSG in CKD subjects, suggesting that changes in GFR are accommodated by glomerular hypertrophy rather than glomerular hypertension. These findings suggest glomerular hypertrophy is a dominant factor in maintenance of GFR under conditions of low nephron number.

Effects of preterm birth and ventilation on glomerular capillary growth in the neonatal lamb kidney

OBJECTIVES

Preterm birth is linked to the development of hypertension later in life. This may relate to impaired glomerular capillary growth following preterm birth. The aim of this study was to determine the effects of preterm birth, and/or ventilation, on glomerular capillary growth in the neonatal lamb kidney.

METHODS

Four experimental groups were analysed: preterm lambs delivered at 130 days gestation (term = 147 days) and mechanically ventilated for 3 days (preterm ventilated: n = 9), 133 days gestational controls (gestational control: n = 5), term controls, unassisted breathing for 3 days (term control: n = 8), and term lambs ventilated for 3 days (term ventilated: n = 5). In perfusion-fixed kidneys, total nephron number, average total capillary length, and surface area per renal corpuscle were stereologically assessed, and total renal filtration surface area (TRFSA) was calculated.

RESULTS

In comparison with term controls, preterm lambs had significantly reduced glomerular capillary length, surface area, and TRFSA, indicative of a low renal functional capacity. Term-ventilated lambs exhibited significantly reduced glomerular capillary length and surface area compared with term controls, indicating that ventilation impairs glomerular capillary growth independently of preterm birth.

CONCLUSION

Impaired glomerular capillary growth and subsequent reduced TRFSA following preterm birth may mediate the increased predisposition to hypertension later in life.

Prenatal compensatory renal growth in unilateral renal agenesis

OBJECTIVE

To create nomograms of fetal renal compensatory growth in cases of unilateral renal agenesis (URA).

METHODS

A retrospective study of fetuses with isolated URA diagnosed prenatally, and confirmed postnatal was performed.

RESULTS

Seventy-four fetuses with isolated solitary kidney were included in the study. A total of 134 measurements of the kidney's length were performed. Ninety five of them were studied longitudinally (2-6 measurements each). The raw values of the compensatory kidney demonstrated a significant correlation with gestational age (Pearson correlation coefficient 0.901, p < 0.001). A quadratic/cubic regression curve, both, described best this relationship, -26.400 + 3.004*GA, -0.026*GA² (r²  = 0.819). The Z score between the mean predicted compensatory kidney's length, per week of gestation, and the mean predicted values of normal kidney length as previously published in the literature, progressively increased during pregnancy (cubic r²  = 0.946 and 0.260).

CONCLUSION

Cases of URA show a unique growth pattern of the single kidney from second trimester to term. Postnatal renal function is dependent on adequate intra-uterine compensatory growth; the presented nomograms provide insight into renal prognosis and add paramount information to the multidisciplinary prenatal counseling of the future parents. © 2016 John Wiley & Sons, Ltd.

The age, breed and sex pattern of diagnosis for veterinary care in insured cats in Japan

OBJECTIVES

To estimate the annual prevalence of different diagnostic categories by age, breed and sex in insured cats in Japan for which veterinary care claims had been made, and to identify if there is a pattern in these host factors.

MATERIALS AND METHODS

Data from 48,187 cats insured for veterinary care in Japan in the period from April 2012 to March 2013 comprising 26,003 males and 22,184 females were analysed to calculate the annual prevalence of 18 diagnostic categories of disease by age, breed and sex.

RESULTS

The prevalence was highest for urinary system disorders (12·2% for males and 10·0% for females), followed by digestive disorders (11·6% for males and 10·7% for females) and dermatological diseases (8·7% for males and 9·0% for females). The male cats had a higher prevalence than female cats for most diagnostic categories. The prevalence of cardiovascular, urinary, endocrine and neoplastic disorders increased with age; infectious and parasitic diseases had high prevalence at young ages, and the prevalence of respiratory, musculoskeletal disorders and injuries had bimodal peaks. Dermatological disorders had a high prevalence at all ages. A large variation in prevalence was observed between breeds for otic, dermatological, dental and cardiovascular disorders.

CLINICAL SIGNIFICANCE

The findings can be used to increase awareness of patterns of health disorders in different categories of cat.

Prenatal Growth and CKD in Older Adults: Longitudinal Findings From the Helsinki Birth Cohort Study, 1924-1944

BACKGROUND

According to the Developmental Origins of Health and Disease (DOHaD) hypothesis, several noncommunicable diseases, including hypertension, type 2 diabetes, and coronary heart disease, have their origins in early life. Chronic kidney disease (CKD) has traditionally been assumed to develop as the result of an interaction between genetic and environmental factors, although more recently, the importance of factors present early in life has been recognized.

STUDY DESIGN

Longitudinal birth cohort study.

SETTING & PARTICIPANTS

20,431 people born in 1924 to 1944 in Helsinki, Finland, who were part of the Helsinki Birth Cohort Study were followed up through their life course from birth until death or age 86 years.

PREDICTOR

Prenatal growth and socioeconomic factors.

OUTCOMES

Death or hospitalization for CKD.

RESULTS

Smaller body size at birth was associated with increased risk for developing CKD. Each standard deviation higher birth weight was associated with an HR for CKD of 0.82 (95% CI, 0.74-0.91; P<0.001). Associations with ponderal index at birth, placental weight, and birth length were also statistically significant (P<0.001, P<0.001, and P=0.002, respectively), but only among men. Prematurity also predicted increased risk for CKD.

LIMITATIONS

The study was restricted to people who were born in Helsinki in 1924 to 1944.

CONCLUSIONS

Smaller body size at birth was associated with increased risk for developing CKD in men. Prematurity was also associated with increased risk for CKD in women. These findings in the Helsinki Birth Cohort Study support the importance of early life factors in the development of CKD.

The Impact of Kidney Development on the Life Course: A Consensus Document for Action

Hypertension and chronic kidney disease (CKD) have a significant impact on global morbidity and mortality. The Low Birth Weight and Nephron Number Working Group has prepared a consensus document aimed to address the relatively neglected issue for the developmental programming of hypertension and CKD. It emerged from a workshop held on April 2, 2016, including eminent internationally recognized experts in the field of obstetrics, neonatology, and nephrology. Through multidisciplinary engagement, the goal of the workshop was to highlight the association between fetal and childhood development and an increased risk of adult diseases, focusing on hypertension and CKD, and to suggest possible practical solutions for the future. The recommendations for action of the consensus workshop are the results of combined clinical experience, shared research expertise, and a review of the literature. They highlight the need to act early to prevent CKD and other related noncommunicable diseases later in life by reducing low birth weight, small for gestational age, prematurity, and low nephron numbers at birth through coordinated interventions. Meeting the current unmet needs would help to define the most cost-effective strategies and to optimize interventions to limit or interrupt the developmental programming cycle of CKD later in life, especially in the poorest part of the world.

Maternal Smoking during Pregnancy, Household Smoking after the Child's Birth, and Childhood Proteinuria at Age 3 Years

BACKGROUND AND OBJECTIVES

Smoking is a well known risk factor of proteinuria in adults; however, clinical studies in children are limited. The purpose of this study is to clarify the associations of maternal smoking during pregnancy and household smoking after the child's birth with the risk of proteinuria at age 3 years old.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We performed a population-based retrospective cohort study on 44,595 children using data on prenatal health checkups, home visit neonatal health checkups, and health checkups at 4, 9, and 18 months and 3 years of age in Kobe City, Japan. Maternal smoking status (nonsmoker, past smoker, or current smoker) was collected with standardized questionnaires. The outcome of interest was the presence of proteinuria at 3 years of age defined as urinary protein ≥1+. To evaluate the association between child proteinuria and smoking status, we performed multivariate logistic regression model analyses adjusted for confounding factors.

RESULTS

The prevalence rates of children in the maternal smoking groups (none, past, and current) were 78.9%, 4.4%, and 16.7%, respectively. The frequencies of child proteinuria defined as ≥1+ urinary protein were 1.7% in the current smoking group, 1.6% in the past smoking group, and 1.3% in the nonsmoking group. Maternal smoking during pregnancy was associated with child proteinuria (odds ratio, 1.24; 95% confidence interval, 1.00 to 1.52; P=0.05) in the multiple logistic regression model, although nonmaternal family smoking during pregnancy was not significantly associated with child proteinuria (odds ratio, 0.97; 95% confidence interval, 0.79 to 1.19; P=0.77). We also found a similar association with household smoking after the child's birth (odds ratio, 1.23; 95% confidence interval, 0.99 to 1.54; P=0.06), although this observation was not significant.

CONCLUSIONS

Maternal smoking during pregnancy was one of the risk factors of childhood proteinuria. We also found a similar association with household smoking after the child's birth, although this observation was not significant.