Hypertension in children with chronic kidney disease: pathophysiology and management

Differential changes in end organ immune cells and inflammation in salt-sensitive hypertension: effects of lowering blood pressure

We reported that salt-sensitive hypertension (SSHTN) is associated with increased pro-inflammatory immune cells, inflammation, and inflammation-associated lymphangiogenesis in the kidneys and gonads of male and female mice. However, it is unknown whether these adverse end organ effects result from increased blood pressure (BP), elevated levels of salt, or both. We hypothesized that pharmaceutically lowering BP would not fully alleviate the renal and gonadal immune cell accumulation, inflammation, and lymphangiogenesis associated with SSHTN. SSHTN was induced in male and female C57BL6/J mice by administering nitro-L-arginine methyl ester hydrochloride (L-NAME; 0.5 mg/ml) in their drinking water for 2 weeks, followed by a 2-week washout period. Subsequently, the mice received a 3-week 4% high salt diet (SSHTN). The treatment group underwent the same SSHTN induction protocol but received hydralazine (HYD; 250 mg/L) in their drinking water during the diet phase (SSHTN+HYD). Control mice received tap water and a standard diet for 7 weeks. In addition to decreasing systolic BP, HYD treatment generally decreased pro-inflammatory immune cells and inflammation in the kidneys and gonads of SSHTN mice. Furthermore, the decrease in BP partially alleviated elevated renal and gonadal lymphatics and improved renal and gonadal function in mice with SSHTN. These data demonstrate that high systemic pressure and salt differentially act on end organ immune cells, contributing to the broader understanding of how BP and salt intake collectively shape immune responses and highlight implications for targeted therapeutic interventions.

Nutritional management of the child with chronic kidney disease and on dialysis

While it is widely accepted that the nutritional management of the infant with chronic kidney disease (CKD) is paramount to achieve normal growth and development, nutritional management is also of importance beyond 1 year of age, particularly in toddlers, to support the delayed infantile stage of growth that may extend to 2-3 years of age. Puberty is also a vulnerable period when nutritional needs are higher to support the expected growth spurt. Inadequate nutritional intake throughout childhood can result in failure to achieve full adult height potential, and there is an increased risk for abnormal neurodevelopment. Conversely, the rising prevalence of overweight and obesity among children with CKD underscores the necessity for effective nutritional strategies to mitigate the risk of metabolic syndrome that is not confined to the post-transplant population. Nutritional management is of primary importance in improving metabolic equilibrium and reducing CKD-related imbalances, particularly as the range of foods eaten by the child widens as they get older (including increased consumption of processed foods), and as CKD progresses. The aim of this review is to integrate the Pediatric Renal Nutrition Taskforce (PRNT) clinical practice recommendations (CPRs) for children (1-18 years) with CKD stages 2-5 and on dialysis (CKD2-5D). We provide a holistic approach to the overall nutritional management of the toddler, child, and young person. Collaboration between physicians and pediatric kidney dietitians is strongly advised to ensure comprehensive and tailored nutritional care for children with CKD, ultimately optimizing their growth and development.

Accuracy and Performance of Triage Blood Pressure Measurements in A Real-World Clinic Setting

OBJECTIVES

To investigate the agreement and accuracy of triage blood pressure (BP) in a real-world clinic setting, compared with the reference standard.

STUDY DESIGN

Paired triage and standardized BP measurements from patients 4 through 21 years old evaluated in an obesity-related hypertension clinic were obtained via chart-review. Triage BPs were measured by a medical assistant or nurse, often by automated device. Triplicate manual BPs were obtained by the clinic physician. Bland-Altman analyses determined mean differences between paired triage and mean standardized BPs. GEE-based multivariable relative risk (RR) regression determined the RR of triage BP overestimation by ≥ 5 mmHg. Overall agreement, sensitivity, specificity, positive predictive value, and negative predictive value of triage BP measurements identifying hypertensive BP were determined.

RESULTS

One hundred thirty participants with 347 clinic encounters were included. Mean age was 13.3 years (SD 3.94), 76% were Black, and 58% were male. Overall mean systolic and diastolic BP difference was 8.7 mmHg (95% limits on agreement: -16.66, 34.07) and 4.1 mmHg (95% limits on agreement: -18.56, 26.68), respectively. Triage systolic BP was more likely overestimated by ≥ 5 mmHg when a large adult (RR = 1.49; 95% CI: 1.00, 2.21) or thigh cuff (RR = 1.94; 95% CI: 1.08, 3.51) was required compared with when a child/adult cuff was required. Overall agreement in identifying hypertensive BP was 57.6%. Sensitivity (52.6%), specificity (63.4%), positive predictive value (60.8%), and negative predictive value (55.3%) were low across all cuffs.

CONCLUSIONS

There was poor agreement between usual triage and standardized BP measurements, with potential for significant clinical implications.

CLINICAL TRIAL REGISTRATION

ReNEW Clinic Cohort Study (ReNEW), NCT03816462, https://clinicaltrials.gov/ct2/show/NCT03816462.

Anti-Hypertensive Property of an NO Nanoparticle in an Adenine-Induced Chronic Kidney Disease Young Rat Model

Hypertension is the most common complication of chronic kidney disease (CKD) in children but is still poorly controlled. Nitric oxide (NO) deficiency plays a pivotal role in CKD and hypertension. NO is known to have health benefits, while NO typically has a short half-life and is not specifically targeted. In this study, we used a pediatric CKD model, which was induced in young rats by feeding them 0.25% adenine. We investigated two different NO donors, namely S-nitrosoglutathione (GSNO) and diethylenetriamine/NO adduct (DETA NONOate) via intraperitoneal injection at 10 mg/kg/day daily for 3 weeks. GSNO was delivered by Cu²⁺-doped zeolitic imidazolate framework (Cu/ZIF-8) nanoparticles to generate NO. As a result, we observed Cu/ZIF-8 nanoparticles were successfully loaded with GSNO and were able to release NO. Young rats fed with adenine displayed kidney dysfunction and hypertension at 9 weeks of age, which were prevented by GSNO-loaded nanoparticle or DETA NONOate treatment. GSNO-loaded nanoparticles reduced CKD-induced hypertension, which was related to an enhanced endogenous NO-generating system, reduced renal oxidative stress, and downregulated several components belonging to the classic renin-angiotensin (RAS) system. Our results cast new light on targeting NO delivery through the use of nanoparticles aiming to improve child-focused outcomes related to CKD worthy of clinical translation.

Erythropoietin in children with hemolytic uremic syndrome: a pilot randomized controlled trial

BACKGROUND

The efficacy of recombinant human erythropoietin (rHuEPO) in sparing red blood cell (RBC) transfusions in children with hemolytic uremic syndrome related to Shiga toxin-producing Escherichia coli (STEC-HUS) is uncertain.

METHODS

We conducted a pilot randomized controlled open trial between December 2018 and January 2021. Children were randomized to the intervention (subcutaneous rHuEPO 50 U/kg three times weekly until discharge + RBC transfusion if hemoglobin ≤ 7 g/dL and/or hemodynamic instability) or to the control arm (RBC transfusion if hemoglobin ≤ 7 g/dL and/or hemodynamic instability). Primary outcome was the number of RBC transfusions received during hospitalization. Secondary outcomes were to explore whether baseline EPO levels were adequate to the degree of anemia, to correlate selected acute phase parameters with the number of RBC transfusions, and to assess possible adverse events.

RESULTS

Twelve patients per arm were included; they were comparable at recruitment and throughout the disease course. Median number of RBC transfusions was similar between groups (1.5, p = 0.76). Most patients had baseline EPO levels adequate to the degree of anemia, which did not correlate with the number of transfusions (r = 0.19, p = 0.44). Conversely, baseline (r = 0.73, p = 0.032) and maximum lactic dehydrogenase levels (r = 0.78, p = 0.003), creatinine peak (r = 0.71, p = 0.03) and dialysis duration (r = 0.7, p = 0.04) correlated significantly with RBC requirements. No side effects were recorded.

CONCLUSION

In children with STEC-HUS, the administration of rHuEPO did not reduce the number of RBC transfusions. Larger studies addressing higher doses and similar severity of kidney failure at rHuEPO initiation (e.g. at start of dialysis) are warranted.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03776851. A higher resolution version of the Graphical abstract is available as Supplementary information.

Plasma Netrin-1 & cardiovascular risk in children with end stage renal disease

Background: Cardiovascular disease (CVD) is the most common cause of mortality and morbidity in children with end stage kidney disease (ESKD) which arises from the interaction of several risk factors. The aim of the study is to assess CV risk of ESKD children and outline the impact of KTX on this CV risk. Also valuate the relation between plasma Netrin-1, chronic inflammatory markers and CV risk. Methods: Sixty ESKD (30 on regular hemodialysis (HD), 30 recipients of kidney transplant (KTX)) were assessed using 24 hour AMBP assessment, laboratory (including lipid profile and markers of chronic inflammation namely N/L and HsCRP) and echocardiographic data. Plasma netrin-1 was assessed by ELISA technique for all patients. Results: showed significant higher prevalence of hypertension, higher number of patients with 24hrs BP> 95th percentile by ABPM, more prevalence of nocturnal non-dipping BP, higher percentage of obese and overweight patients, worse biochemical analysis, higher chance of medical calcification by higher Po4 and Ca X Po4, higher triglyceride level and lower HDL level and higher N/L in HD than KTX group. Significant inverse relation was detected between plasma netrin 1 and Hs CRP and between netrin 1 and N/L (p<0.001).

Perioperative anesthesia care for the pediatric patient undergoing a kidney transplantation: An educational review

Living-donor kidney transplantation is the first choice therapy for children with end-stage renal disease and shows good long-term outcome. Etiology of renal failure, co-morbidities, and hemodynamic effects, due to donor-recipient size mismatch, differs significantly from those in adult patients. Despite the complexities related to both patient and surgery, there is a lack of evidence-based anesthesia guidelines for pediatric kidney transplantation. This educational review summarizes the pathophysiological changes to consider and suggests recommendations for perioperative anesthesia care, based on recent research papers.

Patient and caregiver perspectives on blood pressure in children with chronic kidney disease

BACKGROUND

Over 50% of children with chronic kidney disease (CKD) have uncontrolled hypertension, increasing their long-term risk of cardiovascular disease and progression to kidney failure. Children receiving medications or dialysis may also experience acute blood pressure fluctuations accompanied by debilitating symptoms. We aimed to describe the perspectives of children with CKD and their parental caregivers on blood pressure, to inform patient-centered care.

METHODS

Secondary thematic analysis was conducted on qualitative data from the Standardized Outcomes in Nephrology-Children and Adolescents initiative, encompassing 16 focus groups, an international Delphi survey, and two consensus workshops. We analyzed responses from children with CKD (aged 8-21 years) and caregivers (of children aged 0-21 years) pertaining to blood pressure.

RESULTS

Overall, 120 patients and 250 caregivers from 22 countries participated. We identified five themes: invisibility and normalization (reassured by apparent normotension, absence of symptoms, expected links with CKD); confused by ambiguity (hypertension indistinguishable from cardiovascular disease, questioning need for prophylactic intervention, frustrated by inconsistent messages, struggling with technical skills in measurement); enabling monitoring and maintaining health (gauging wellbeing, preventing vascular complications); debilitating and constraining daily living (provoking anxiety and agitation, helpless and powerless, limiting life activities); and burden of medications (overwhelmed by quantity of tablets, distress from unexpected side effects).

CONCLUSIONS

For children with CKD and their caregivers, blood pressure was an important heath indicator, but uncertainty around its implications and treatment hampered management. Providing educational resources to track blood pressure, and minimizing symptoms and treatment burden, may improve outcomes in children with CKD.

Genetic susceptibility of hypertension-induced kidney disease

Hypertension is the second leading cause of end-stage renal disease (ESRD) after diabetes mellitus. The significant differences in the incidence of hypertensive ESRD between different patient populations worldwide and patients with and without family history indicate that genetic determinants play an important role in the onset and progression of this disease. Recent studies have identified genetic variants and pathways that may contribute to the alteration of renal function. Mechanisms involved include affecting renal hemodynamics (the myogenic and tubuloglomerular feedback responses); increasing the production of reactive oxygen species in the tubules; altering immune cell function; changing the number, structure, and function of podocytes that directly cause glomerular damage. Studies with hypertensive animal models using substitution mapping and gene knockout strategies have identified multiple candidate genes associated with the development of hypertension and subsequent renal injury. Genome-wide association studies have implicated genetic variants in UMOD, MYH9, APOL-1, SHROOM3, RAB38, and DAB2 have a higher risk for ESRD in hypertensive patients. These findings provide genetic evidence of potential novel targets for drug development and gene therapy to design individualized treatment of hypertension and related renal injury.

Hypertensive Crisis in Pediatric Patients: An Overview

Hypertensive crisis can be a source of morbidity and mortality in the pediatric population. While the epidemiology has been difficult to pinpoint, it is well-known that secondary causes of pediatric hypertension contribute to a greater incidence of hypertensive crisis in pediatrics. Hypertensive crisis may manifest with non-specific symptoms as well as distinct and acute symptoms in the presence of end-organ damage. Hypertensive emergency, the form of hypertensive crisis with end-organ damage, may present with more severe symptoms and lead to permanent organ damage. Thus, it is crucial to evaluate any pediatric patient suspected of hypertensive emergency with a thorough workup while acutely treating the elevated blood pressure in a gradual manner. Management of hypertensive crisis is chosen based on the presence of end-organ damage and can range from fast-acting intravenous medication to oral medication for less severe cases. Treatment of such demands a careful balance between decreasing blood pressure in a gradual manner while preventing damage end-organ damage. In special situations, protocols have been established for treatment of hypertensive crisis, such as in the presence of endocrinologic neoplasms, monogenic causes of hypertension, renal diseases, and cardiac disease. With the advent of telehealth, clinicians are further able to extend their reach of care to emergency settings and aid emergency medical service (EMS) providers in real time. In addition, further updates on the evolving topic of hypertension in the pediatric population and novel drug development continues to improve outcomes and efficiency in diagnosis and management of hypertension and consequent hypertensive crisis.

Oxidative stress in chronic kidney disease

Oxidative stress (OS), defined as disturbances in the pro-/antioxidant balance, is harmful to cells due to the excessive generation of highly reactive oxygen (ROS) and nitrogen (RNS) species. When the balance is not disturbed, OS has a role in physiological adaptations and signal transduction. However, an excessive amount of ROS and RNS results in the oxidation of biological molecules such as lipids, proteins, and DNA. Oxidative stress has been reported in kidney disease, due to both antioxidant depletions as well as increased ROS production. The kidney is a highly metabolic organ, rich in oxidation reactions in mitochondria, which makes it vulnerable to damage caused by OS, and several studies have shown that OS can accelerate kidney disease progression. Also, in patients at advanced stages of chronic kidney disease (CKD), increased OS is associated with complications such as hypertension, atherosclerosis, inflammation, and anemia. In this review, we aim to describe OS and its influence on CKD progression and its complications. We also discuss the potential role of various antioxidants and pharmacological agents, which may represent potential therapeutic targets to reduce OS in both pediatric and adult CKD patients.

Management of Hypertension in CAKUT: Protective Factor for CKD

Patients with congenital kidney and urinary tract abnormalities (CAKUT) will often develop end-stage renal disease at some point and the need for renal replacement therapy is associated with high rates of morbidity and mortality. Hence, efforts to slow the progression of the disease are essential. Hypertension has been proven to be an independent risk factor for faster decline of glomerular filtration rate in renal patients, but studies involving only children with CAKUT are scarce. We performed a literature review to explore the association of hypertension with faster chronic kidney disease progression in children with CAKUT and also treatment options in this condition. A recent study reported an annual decline in GFR of 1.8 ml/min/1.73 m² among hypertensive patients with non-glomerular CKD, compared with 0.8 ml/min/1.73 m² in normotensive children. A multicenter prospective cohort in Brazil showed that a 1-unit increase in systolic blood pressure Z-score was associated with a 1.5-fold higher risk of disease progression. Since renin-angiotensin-aldosterone system activation is the most important mechanism of hypertension in these children, the first-line therapy involves the use of inhibitors of this axis, including angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers type I, which also promote an anti-fibrotic effect. Recent studies have shown a good safety profile for use in patients with chronic kidney disease and also in those with solitary kidneys. Hypertension is an independent risk factor for kidney disease progression and should be promptly managed for renal protection, especially among patients with CAKUT, the primary cause of chronic kidney disease in the pediatric population.

Role of hypertension in progression of chronic kidney disease in children

PURPOSE OF REVIEW

Hypertension is an independent risk factor for progression of chronic kidney disease (CKD) in children. Children with early CKD develop hypertension secondary to renal disease. This review aims to highlight recent advances that help us better understand the current role of hypertension in progression of CKD in children.

RECENT FINDINGS

There is increasing evidence that children with CKD who have hypertension develop early atherosclerosis and cardiac adaptive changes. Emerging data from pediatric research in CKD show that elevated blood pressure is associated with the presence of abnormal subclinical markers of cardiovascular disease including increased carotid intima-media thickness, pulse wave velocity and left ventricular mass index. There is also some evidence that these early cardiovascular changes are reversible. Twenty-four hour ambulatory blood pressure monitoring (ABPM) is recommended in children with CKD by the American Academy of Pediatrics to diagnose hypertension.

SUMMARY

Hypertension is associated with subclinical cardiovascular disease in children with CKD. Early diagnosis of hypertension by ABPM and identification of subclinical cardiovascular changes provide a window for intervention, which may reverse early cardiovascular disease, thereby delaying dialysis and improving cardiovascular morbidity and mortality.

Blood pressure management in children on dialysis

Hypertension is a leading cause of cardiovascular complications in children on dialysis. Volume overload and activation of the renin-angiotensin-aldosterone system play a major role in the pathophysiology of hypertension. The first step in managing blood pressure (BP) is the careful assessment of ambulatory BP monitoring. Volume control is essential and should start with the accurate identification of dry weight, based on a comprehensive assessment, including bioimpedance analysis and intradialytic blood volume monitoring (BVM). Reduction of interdialytic weight gain (IDWG) is critical, as higher IDWG is associated with a worse left ventricular mass index and poorer BP control: it can be obtained by means of salt restriction, reduced fluid intake, and optimized sodium removal in dialysis. Optimization of peritoneal dialysis and intensified hemodialysis or hemodiafiltration have been shown to improve both fluid and sodium management, leading to better BP levels. Studies comparing different antihypertensive agents in children are lacking. The pharmacokinetic properties of each drug should be considered. At present, BP control remains suboptimal in many patients and efforts are needed to improve the long-term outcomes of children on dialysis.

Development of tandem mass spectrometry-based creatinine measurement using dried blood spot for newborn mass screening

BackgroundCongenital anomalies of the kidney and urinary tract (CAKUT) are the most prevalent etiologies of pediatric chronic kidney disease (CKD). However, no robust mass screening methods have been developed to detect patients with CAKUT, making early intervention to prevent progressive renal failure challenging.MethodsWe applied tandem mass spectrometry (MS/MS) to measure the creatinine (Cr) value from dried blood spot (DBS) analysis, which has been used for newborn mass screening. Subsequently, we evaluated the correlation between DBS Cr measured by MS/MS and serum Cr measured by the conventional method in pediatric patients with CKD. Finally, DBS Cr was measured in 190 full-term, healthy newborns on days 4-6 after birth.ResultsWe established a system of MS/MS-based measurement of Cr from DBS. Measured DBS Cr in the pediatric patients showed a strong association with serum Cr (r=0.86; P<0.01). The median DBS Cr value in newborns was 0.222 (interquartile range: 0.189, 0.269) mg/dl. No significant correlations were found between DBS Cr values and body weight, Apgar score, gestational age, and sex in newborns.ConclusionWe successfully established a method for MS/MS-based measurement of Cr for newborn screening and determined normal reference values for full-term newborns.

Hypertension in pediatric patients with chronic kidney disease: management challenges

In contrast to adults where hypertension is a leading cause of chronic kidney disease, in pediatrics, hypertension is predominantly a sequela, however, an important one that, like in adults, is likely associated with a more rapid decline in kidney function or progression of chronic kidney disease to end stage. There is a significant issue with unrecognized, or masked, hypertension in childhood chronic kidney disease. Recent evidence and, therefore, guidelines now suggest targeting a blood pressure of <50th percentile for age, sex, and height in children with proteinuria and chronic kidney disease. This often cannot be achieved by monotherapy and additional agents need to be added. Blockade of the renin angiotensin aldosterone system represents the mainstay of therapy, although often limited by the side effect of hyperkalemia. The addition of a diuretic, at least in the earlier stages of chronic kidney disease, might help mitigate this problem.

What has changed in the prevalence of hypertension in dialyzed children during the last decade?

BACKGROUND

Hypertension very often accompanies progression of chronic kidney disease (CKD) in children. A cross-sectional analysis of hypertension prevalence in dialyzed children in Poland was designed with a comparison with the data previously recorded 10 years earlier.

METHODS

Two cohorts of children were analyzed: 59 subjects dialyzed in 2013, and 134 children from the previous study performed in 2003 that were reevaluated according to the current methodology. The incidence of hypertension (defined by SDS of sBP or dBP >1.64), clinical data, medical history, dialysis modalities and selected biochemical parameters of dialysis adequacy were analyzed.

RESULTS

The prevalence of hypertension increased from 64% in 2003 to 78% in 2013. The efficacy of antihypertensive treatment remained unsatisfactory (61% proper BP control). Preservation of residual urine output and strict fluid balance may prevent development of hypertension in children on dialysis.

CONCLUSIONS

Despite the higher awareness of hypertension and its complications in dialyzed children, the incidence of this entity has increased during the last decade, with the percentage of undertreated patients comparable to that observed 10 years ago. Thus, more attention should be paid to therapy efficacy in this population to prevent further damage to the cardiovascular system and to decrease morbidity.

Central role for melanocortin-4 receptors in offspring hypertension arising from maternal obesity

Melanocortin-4 receptor (Mc4r)-expressing neurons in the autonomic nervous system, particularly in the paraventricular nucleus of the hypothalamus (PVH), play an essential role in blood pressure (BP) control. Mc4r-deficient (Mc4rKO) mice are severely obese but lack obesity-related hypertension; they also show a reduced pressor response to salt loading. We have previously reported that lean juvenile offspring born to diet-induced obese rats (OffOb) exhibit sympathetic-mediated hypertension, and we proposed a role for postnatally raised leptin in its etiology. Here, we test the hypothesis that neonatal hyperleptinemia due to maternal obesity induces persistent changes in the central melanocortin system, thereby contributing to offspring hypertension. Working on the OffOb paradigm in both sexes and using transgenic technology to restore Mc4r in the PVH of Mc4rKO (Mc4rPVH) mice, we have now shown that these mice develop higher BP than Mc4rKO or WT mice. We have also found that experimental hyperleptinemia induced in the neonatal period in Mc4rPVH and WT mice, but not in the Mc4rKO mice, leads to heightened BP and severe renal dysfunction. Thus, Mc4r in the PVH appears to be required for early-life programming of hypertension arising from either maternal obesity or neonatal hyperleptinemia. Early-life exposure of the PVH to maternal obesity through postnatal elevation of leptin may have long-term consequences for cardiovascular health.

Finding covert fluid: methods for detecting volume overload in children on dialysis

BACKGROUND

Lung ultrasound is a novel technique for detecting generalized fluid overload in children and adults with end-stage renal disease (ESRD). Echocardiography and bioimpedance spectroscopy are established methods, albeit variably adopted in clinical practice. We compared the practicality and accuracy of lung ultrasound with current objective techniques for detecting fluid overload in children with ESRD.

METHODS

A prospective observational study was performed to compare lung ultrasound B-lines, echocardiographic measurement of inferior vena cava parameters and bioimpedance spectroscopy in the assessment of fluid overload in children with ESRD on dialysis. The utility of each technique in predicting fluid overload, based on short-term weight gain, was assessed. Multiple linear regression models to predict fluid overload by weight were explored.

RESULTS

A total of 22 fluid assessments were performed in 13 children (8 on peritoneal dialysis, 5 on haemodialysis) with a median age of 4.0 (range 0.8-14.0) years. A significant linear correlation was observed between the number of B-lines detected by lung ultrasound and fluid overload by weight (r = 0.57, p = 0.005). A non-significant positive linear correlation was observed between fluid overload by weight and bioimpedance spectroscopy (r = 0.43, p = 0.2), systolic blood pressure (r = 0.19, p = 0.4) and physical examination measurements (r = 0.19, p = 0.4), while a non-significant negative linear relationship was found between the inferior vena cava collapsibility index and fluid overload by weight (r = -0.24, p = 0.3). In multiple linear regression models, a combination of three fluid parameters, namely lung ultrasound B-lines, clinical examination and systolic blood pressure, best predicted fluid overload (R ²  = 0.46, p = 0.05).

CONCLUSIONS

Lung ultrasound may be superior to echocardiographic methods and bioimpedance spectroscopy in detecting volume overload in children with ESRD. Given the practicality and sensitivity of this new technique, it can be adopted alongside clinical examination and blood pressure in the routine assessment of fluid status in children with ESRD.

Renal and Cardiovascular Morbidities Associated with APOL1 Status among African-American and Non-African-American Children with Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

African-American (AA) children with focal segmental glomerulosclerosis (FSGS) have later onset disease that progresses more rapidly than in non-AA children. It is unclear how APOL1 genotypes contribute to kidney disease risk, progression, and cardiovascular morbidity in children.

DESIGN SETTING PARTICIPANTS AND MEASUREMENTS

We examined the prevalence of APOL1 genotypes and associated cardiovascular phenotypes among children with FSGS in the Chronic Kidney Disease in Children (CKiD) study; an ongoing multicenter prospective cohort study of children aged 1-16 years with mild to moderate kidney disease.

RESULTS

A total of 140 AA children in the CKiD study were genotyped. High risk (HR) APOL1 genotypes were present in 24% of AA children (33/140) and were associated with FSGS, p < 0.001. FSGS was the most common cause of glomerular disease in children with HR APOL1 (89%; 25/28). Of 32 AA children with FSGS, 25 (78%) had HR APOL1. Compared to children with low risk APOL1 and FSGS (comprising 36 non-AA and 7 AA), children with HR APOL1 developed FSGS at a later age, 12.0 (IQR: 9.5, 12.5) vs. 5.5 (2.5, 11.5) years, p = 0.004, had a higher prevalence of uncontrolled hypertension (52 vs. 33%, p = 0.13), left ventricular hypertrophy (LVH) (53 vs. 12%, p < 0.01), C-reactive protein > 3 mg/l (33 vs. 15%, p = 0.12), and obesity (48 vs. 19%, p = 0.01). There were no differences in glomerular filtration rate, hemoglobin, iPTH, or calcium-phosphate product.

CONCLUSION

AA children with HR APOL1 genotype and FSGS have increase prevalence of obesity and LVH despite a later age of FSGS onset, while adjusting for socioeconomic status. Treatment of obesity may be an important component of chronic kidney disease and LVH management in this population.

Pre-treatment considerations in childhood hypertension due to chronic kidney disease

Hypertension (HTN) develops very early in childhood chronic kidney disease (CKD). It is linked with rapid progression of kidney disease, increased morbidity and mortality hence the imperative to start anti-hypertensive medication when blood pressure (BP) is persistently > 90^th percentile for age, gender, and height in non-dialyzing hypertensive children with CKD. HTN pathomechanism in CKD is multifactorial and complexly interwoven. The patient with CKD-associated HTN needs to be carefully evaluated for co-morbidities that frequently alter the course of the disease as successful treatment of HTN in CKD goes beyond life style modification and anti-hypertensive therapy alone. Chronic anaemia, volume overload, endothelial dysfunction, arterial media calcification, and metabolic derangements like secondary hyperparathyroidism, hyperphosphataemia, and calcitriol deficiency are a few co-morbidities that may cause or worsen HTN in CKD. It is important to know if the HTN is caused or made worse by the toxic effects of medications like erythropoietin, cyclosporine, tacrolimus, corticosteroids and non-steroidal anti-inflammatory drugs. Poor treatment response may be due to any of these co-morbidities and medications. A satisfactory hypertensive CKD outcome, therefore, depends very much on identifying and managing these co-morbid conditions and HTN promoting medications promptly and appropriately. This review attempts to point attention to factors that may affect successful treatment of the hypertensive CKD child and how to attain the desired therapeutic BP target.

Hypertension in children with end-stage renal disease

This review summarizes current data on the epidemiology, pathophysiology, and treatment of hypertension (HTN) in children with end-stage renal disease (ESRD). Worldwide prevalence of ESRD ranges from 5.0 to 84.4 per million age-related population. HTN is present in 27-79% of children with ESRD, depending on the modality of renal replacement therapy and the exact definition of hypertension. Ambulatory BP monitoring has been recommended for the detection of HTN and evaluation of treatment effectiveness. HTN in dialyzed patients is mostly related to hypervolemia, sodium overload, activation of the renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system, impaired nitric oxide synthesis, reduced vitamin D levels, and effects of microRNA. In children undergoing chronic dialysis therapy, important factors include optimization of renal replacement therapy and preservation of residual renal function, allowing reduction of volume- and sodium-overload, along with appropriate drug treatment, particularly with calcium channel blockers, RAAS inhibitors, and loop diuretics.

The impact of kidney transplantation on 24-hour ambulatory blood pressure in end-stage renal disease patients

In this study, we prospectively investigated the impact of kidney transplantation (KT) on the status of hypertension, including circadian rhythm in end-stage renal disease (ESRD) patients. We performed 24-hour ambulatory blood pressure (BP) monitoring and office BP measurement in 48 patients before and 1 year after KT. According to the nocturnal reduction in systolic BP (ΔSBP), the patients were divided into dippers, non-dippers, and reverse dippers. After KT, the mean BP value in office BP and 24-hour ambulatory BP monitoring did not change, but the proportion of patients taking anti-hypertensive drugs and the pill number significantly decreased. In contrast, the mean ΔSBP significantly decreased, and the proportion of non-dippers and reverse dippers did not decrease. Decrease in ΔSBP after KT was associated with inferior allograft function during follow-up. Our study suggests that KT improved the overall BP level, but it did not affect abnormal circadian rhythm in ESRD patients.

Early erythropoietin in post-diarrheal hemolytic uremic syndrome: a case-control study

BACKGROUND

Although erythropoietin (EPO) deficiency has been reported in children with post-diarrheal hemolytic uremic syndrome (D + HUS), very limited clinical data on EPO use in this disease are currently available. In this case-control study we examined whether EPO administration would reduce the number of red blood cell (RBC) transfusions in D + HUS patients under our care.

METHODS

Data from children treated exclusively with RBC transfusions (controls; n = 21) were retrospectively compared with data on those who also received EPO for the treatment of anemia (cases; n = 21).

RESULTS

Both patient groups were similar in age (p = 0.9), gender (p = 0.12), weight (p = 1.00) and height (p = 0.66). Acute phase severity was also comparable, as inferred by the need for dialysis (p = 0.74), the duration of dialysis (p = 0.3), length of hospitalization (p = 0.81), presence of severe bowel (p = 1.00) or neurological injury (p = 0.69), arterial hypertension (p = 1.00) and death (p = 1.00). No differences in the hemoglobin level at admission (p = 0.51) and discharge (p = 0.28) were noted. Three children treated with EPO and two controls did not require any RBC transfusion (p = 1.00). Median number of RBC transfusions needed by cases and controls was 2 (p = 0.52).

CONCLUSION

Treatment with EPO did not reduce the number of RBC transfusions in D + HUS children. Assessment of EPO efficacy in D + HUS merits further studies.

Progression to end-stage kidney disease in Japanese children with chronic kidney disease: results of a nationwide prospective cohort study

BACKGROUND

The risk of progressing to end-stage kidney disease (ESKD) and factors associated with progression in children with chronic kidney disease (CKD) are unclear, especially in Asian children.

METHODS

We started a nationwide, prospective cohort study of 447 Japanese children with pre-dialysis CKD in 2010, with follow-up in 2011. Progression to ESKD was analyzed by Kaplan-Meier analysis according to CKD stage. Cox regression analysis was used to identify risk factors for progression.

RESULTS

Data were analyzed for 429/447 children. Five patients died, of which four died before progression to ESKD. Fifty-two patients progressed to ESKD (median follow-up 1.49 years), including 9/315 patients with stage 3 CKD, 29/107 with Stage 4 CKD and 14/25 with Stage 5 CKD. One-year renal survival rates were 98.3, 80.0 and 40.9%, for Stages 3, 4 and 5 CKD, respectively. Risk factors for progression to ESKD included CKD stage [versus Stage 3; Stage 4: hazard ratio (HR) 11.12, 95% confidence interval (CI) 4.22-29.28, P < 0.001; Stage 5: HR 26.95, 95% CI 7.71-94.17, P < 0.001], heavy proteinuria (>2.0 g/g urine creatinine; HR 7.56, 95% CI 3.22-17.77, P < 0.001) and age ( < 2 years: HR 9.06; 95% CI 2.29-35.84, P = 0.002; after starting puberty: HR 4.88; 95% CI 1.85-12.85, P = 0.001).

CONCLUSIONS

In this cohort, 12.5% of children with pre-dialysis CKD progressed to ESKD with a median-follow-up of 1.49 years. Children with advanced (Stage 4/5) CKD were particularly likely to progress. To our knowledge, this is the first, nationwide, prospective cohort study of children with pre-dialysis CKD in Asia.

Disparities in antihypertensive medication adherence in adolescents

BACKGROUND

Hypertension affects up to 5 % of all children, but little is known about the role of medication adherence on blood pressure (BP) control. In this study we examined the association between adolescents' antihypertensive medication adherence and BP control, investigating for racial disparities.

METHODS

A total of 21 adolescents with essential hypertension [mean age 14.7 ± 2.0 years, 57 % male, 52 % African American] were recruited from a pediatric nephrology clinic. Objective medication adherence measures were obtained with Medication Event Monitoring System (MEMS) caps and pharmacy refill records to determine medication possession ratios (MPRs).

RESULTS

The African Americans adolescents had lower medication adherence than non-African Americans adolescents based on the MPR over the past 12 months (mean 0.54 ± 0.21 vs. 0.85 ± 0.16, respectively; p < 0.001) and a trend for less adherence measured by MEMS caps over the last 28 days (mean 0.75 ± 0.26 vs. 0.91 ± 0.04, respectively; p < 0.07). Seven of the eight participants with low adherence (MPR <0.65) had uncontrolled BP (systolic and/or diastolic BPs ≥ 95th percentile), and no participants with high adherence according to the MPR had uncontrolled BP (p < 0.001). There was no difference in BP control by race.

CONCLUSIONS

Antihypertensive medication adherence measured by pharmacy refills was associated with BP control. AAs were more likely to have lower medication adherence. Targeting medication adherence through the use of electronic medical records may be a potential mechanism to reduce health disparities.

Arterial hypertension and progression of chronic kidney disease in children during 10-year ambulatory observation

The aim of this study was the long-term retrospective analysis of chronic kidney disease (CKD) progression in children, especially with regard to the presence of hypertension (HTN). The average rate of progression of CKD was higher in patients with HTN than without HTN. Hypertension treatment requires multidrug schemes which need to be intensified with extended time of CKD duration.

Losartan and enalapril are comparable in reducing proteinuria in children

Angiotensin-converting enzyme inhibitors and angiotensin II type I receptor blockers delay progression of chronic kidney disease and have antiproteinuric effects beyond their effects on blood pressure. They are routinely used in adults; however, their efficacy and safety in children, in whom the causes of chronic kidney disease are significantly different relative to adults, is uncertain. Here we assessed an open-label extension of a previous 3-month blinded trial, in which the efficacy and tolerability of losartan was compared to placebo or amlodipine in 306 normotensive and hypertensive children with proteinuria. In this study, 268 children were re-randomized to losartan or enalapril and followed until 100 patients completed 3 years of follow-up for proteinuria and renal function. The least squares percent mean reduction from baseline in the urinary protein/creatinine ratio was 30.01% for losartan and 40.45% for enalapril. The least squares mean change from baseline in eGFR was 3.3 ml/min per 1.73 m2 for losartan and 7.0 ml/min per 1.73 m2 for enalapril. The incidence of specific adverse events such as hyperkalemia and renal dysfunction was low and similar in both groups. Both were generally well tolerated and, overall, fewer drug-related adverse events occurred with losartan than with enalapril. Thus, in children with proteinuria, losartan and enalapril significantly reduced proteinuria without any appreciable changes in eGFR, effects that were maintained throughout the study. Both losartan and enalapril were generally well tolerated.

Systemic arterial hypertension in children following renal transplantation: prevalence and risk factors

BACKGROUND

Control of blood pressure (BP) following renal transplantation may improve allograft and patient survival. Our aims were (i) to describe the distribution of BP and the prevalence of systolic and/or diastolic hypertension in children over the first 5 years following renal transplantation and (ii) to evaluate clinical risk factors and centre-specific factors associated with hypertension in this population.

METHODS

We conducted a retrospective case note review of all current paediatric kidney transplant patients in the UK, with data collected at 6 months, 1, 2 and 5 years following transplantation in subjects with hypertension (systolic and/or diastolic BP > 95th > ) and non-hypertensive subjects BP ≤ 95th > .

RESULTS

In total, 27.3% (117/428), 27.6% (118/428), 26.0% (95/365) and 25.6% (50/195) of the patients were hypertensive (systolic and/or diastolic BP > 95th > ) at 6 months, 1, 2 and 5 years following transplantation, respectively. A total of 58.4% of the patients at 6 months, 52.8% at 1 year, 48.2% at 2 years and 48.2% at 5 years were receiving anti-hypertensive therapy, of whom 31.6-36.6% remained hypertensive. When subjects were identified as being hypertensive, on anti-hypertensive medication or had untreated hypertension (systolic and/or diastolic BP > 95th > ), 66.4, 61.0, 56.4 and 55.9% of patients were hypertensive at 6 months, 1, 2 and 5 years, respectively. In a multivariate model, odds ratios for systolic hypertension were 4.16 (deceased versus living donor), 2.65 (lowest versus highest quartile of height z-score) and 2.07 (if on anti-hypertensive; yes versus no). There was significant variation in prevalent rates of hypertension between centres (P < 0.0001) that remained significant (P = 0.003) after adjustment for all the factors in the multivariate model.

CONCLUSIONS

Control of BP after kidney transplantation remains sub-optimal in paediatric centres in the UK. Just over 25% of patients remain hypertensive 5 years following transplantation. Significant differences between centres remain unexplained and may reflect differences in assessment and management of hypertension.

Epidemiology, pathophysiology, clinical characteristics and management of childhood cardiorenal syndrome

Cardiorenal syndrome (CRS) is a new term recently introduced to describe the acute or chronic comorbid state of the heart and kidney that has been long known and frequently managed in very sick individuals. The tight and delicate coordination of physiological functions among organ systems in the human body makes dysfunction in one to lead to malfunction of one or more other organ systems. CRS is a universal very common morbidity in the critically ill, with a high mortality rate that has received very little research attention in children. Simultaneous management of heart and renal failures in CRS is quite challenging; the therapeutic choice made for one organ must not jeopardize the other. This paper reviews the epidemiology, pathophysiology, clinical characteristics and management of acute and chronic CRS in children.

Exercise for children with chronic kidney disease and end-stage renal disease

It is well known that adults suffering from chronic kidney disease (CKD) experience muscle wasting and excessive fatigue, which results in a reduced exercise capacity and muscle weakness compared to their healthy counterparts, but research suggests that this can be improved through exercise. There is very limited data available regarding exercise tolerance in children with CKD and even less on the effects of exercise training programs. However, the available evidence does suggest that like adults, children also suffer from poor exercise capacity and reduced muscle strength, although the reasons for these limitations remain unclear. Studies that have attempted to implement exercise training programs in pediatric CKD populations have experienced high dropout rates, suggesting that the approach used to implement such programs in children needs to be different from the approach used for adults. This review summarizes the current knowledge regarding exercise capacity and muscle strength in children with CKD, the methods used to perform these assessments, and the possible causes of physical limitations. The results of exercise training studies, and the potential reasons as to why training programs have proved relatively unsuccessful are also discussed.

Hypertension and CKD

Hypertension is found in more than 50% of pediatric patients with CKD. However, its prevalence varies according to the cause of CKD. It is relatively infrequent in children with structural disorders. Acquired renal disorders are associated with an increased prevalence of hypertension, similar to that of adults. Recent studies using ambulatory blood pressure monitoring indicate that children with CKD also have a high prevalence of masked hypertension. Similar to adults, long-standing and uncontrolled hypertension in children is associated with the progression of CKD and development of end-organ damage including early cardiomyopathy and premature atherosclerosis. Aggressive treatment of hypertension should be an essential part of pediatric CKD care, not just to prevent the development of symptomatic cardiovascular disease but also to delay progression of CKD. Recent findings from the European Effect of Strict Blood Pressure Control and ACE Inhibition on Progression of Chronic Renal Failure in Pediatric Patients (ESCAPE) trial have shown that the aggressive treatment of blood pressure, to below the 50th percentile, has even greater benefit in children with CKD, unlike results seen in adult studies.

Role of twenty-four-hour ambulatory blood pressure monitoring in children on dialysis

BACKGROUND AND OBJECTIVES

Pre- or postdialysis BP recordings are imprecise, can be biased, and have poor test-retest reliability in children on dialysis. We aimed to examine the possible differences between pre- and postdialysis BP levels and 24-hour ambulatory BP monitoring (ABPM) in diagnosis of hypertension (HTN).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Twenty-four children on dialysis had 24-hour ABPM in the interdialytic period, and values were compared with average pre- and postdialysis systolic BP (SBP) and diastolic BP (DBP) recordings that week. Each patient had an echocardiogram to determine presence of left ventricular hypertrophy (LVH).

RESULTS

By ABPM, 8% of patients had white coat HTN and 12% had masked HTN. There was no significant difference in diagnosis of systolic HTN based on ABPM daytime SBP mean or load and postdialysis SBP. However, only 15% of patients had diastolic HTN based on postdialysis measures, whereas 46% of patients had significantly elevated daytime DBP loads and 71% had high nighttime DBP loads on ABPM. Forty-eight percent of patients were SBP nondippers. Children with LVH had higher daytime and nighttime SBP loads, significantly higher daytime and nighttime DBP loads, and lesser degree of nocturnal dipping of SBP compared with those who did not.

CONCLUSION

ABPM is more informative than pre- and postdialysis BPs and improves the predictability of BP as a risk factor for target organ damage. Diagnosis and treatment monitoring of HTN among pediatric dialysis patients is enhanced with addition of ABPM.

Vasculitides associated with IgG antineutrophil cytoplasmic autoantibodies in childhood

Immunoglobulin (Ig)G antineutrophil cytoplasmic autoantibodies are causally associated with necrotizing vasculitides that are characterized immunopathologically by little or no deposition of immunoreactants, such as Wegener granulomatosis, microscopic polyangiitis, Churg-Strauss angiitis, "renal-limited" vasculitis and a number of drug-induced vasculitides. Clinical routine testing targets the antigens myeloperoxidase and proteinase 3. However, in all of the conditions mentioned, the renal histopathologic findings are indistinguishable. Churg-Strauss angiitis (characterized by necrotizing vasculitis, granulomatous inflammation and tissue eosinophilia), Wegener granulomatosis (characterized by necrotizing vasculitis and granulomatous inflammation) and microscopic polyangiitis (characterized by necrotizing vasculitis) often present with fever, weight loss and a multisystem involvement (ear, nose, throat, lung, eyes, peripheral nerve and heart). Fifty years ago these conditions were very often fatal within 6 months of diagnosis. The introduction of corticosteroids and cyclophosphamide has resulted in a dramatic clinical benefit. Patients who develop treatment-related morbidity can be switched from cyclophosphamide to azathioprine after achieving remission. In patients with less severe disease, methotrexate achieves remission with a success rate similar to that of cyclophosphamide. Plasma exchange, in association with immunosuppression, is likely to be a beneficial therapy for patients with severe kidney disease or pulmonary hemorrhage.

Randomized, double-blind, controlled study of losartan in children with proteinuria

BACKGROUND AND OBJECTIVES

No large, randomized, double-blind trials in children with proteinuria treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers have previously been reported.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This 12-week, double-blind, multinational study investigated the effects of losartan 0.7 to 1.4 mg/kg per day compared with placebo (normotensive stratum) or amlodipine 0.1 to 0.2 mg/kg per day up to 5 mg/d (hypertensive stratum) on proteinuria (morning-void urinary protein-creatinine ratio, baseline > or =0.3 g/g) in 306 children up to 17 years of age.

RESULTS

Twelve weeks of treatment with losartan significantly reduced proteinuria compared with amlodipine/placebo: losartan -35.8% (95% confidence interval: -27.6% to -43.1%) versus amlodipine/placebo 1.4% (95% confidence interval: -10.3% to 14.5%), P < or = 0.001. Significance remained after adjustment for differences across treatment groups in change in BP (losartan produced incremental systolic and diastolic BP reductions versus amlodipine of 5.4 and 4.6 mmHg, respectively; and versus placebo of 3.8 and 4.0 mmHg, respectively). Proteinuria reduction was consistently observed in the normotensive (-34.4% losartan; 2.6% placebo) and hypertensive (-41.5% losartan; 2.4% amlodipine) strata, and in all prespecified subgroups, including age, gender, race, Tanner stage, weight, prior therapy with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers, as well as among the most common etiologies of proteinuria. Adverse event incidence was low and comparable in all groups.

CONCLUSIONS

Losartan significantly lowered proteinuria and was well tolerated after 12 weeks in children aged 1 to 17 years with proteinuria with or without hypertension, a population that has not previously been rigorously studied.

Effect of obesity on response to cardiovascular drugs in pediatric patients with renal disease

Obesity is associated with an increased concentration of inflammatory mediators, which in turn, in adults, reduces the response to calcium channel blockers (CCBs). We reviewed the medical charts of 263 pediatric nephrology patients with renal conditions, with the aim of studying the effect of obesity on the response to L-type CCBs, angiotensin interrupting agents (ANGIs), or a combination of the two. Forty-eight patients were ultimately enrolled in the study: 25 obese and 23 non-obese patients. The effect of the treatments on lowering the blood pressure was compared in obese versus non-obese patients. The systolic response to CCBs, measured as at least a 10% reduction from the baseline, was significantly lower in the obese (12.5%) patients than in the non-obese (52.9%) ones. The differences in diastolic response (58.8 and 25% for non-obese and obese patients, respectively) did not reach significance. The percentage response to CCBs, however, was significantly less in the obese patients than in the non-obese patients for both systolic and diastolic blood pressure. Corticosteroids also significantly influenced the response to CCBs in terms of diastolic pressure (62.9 and 25% for non-obese and obese patients, respectively). None of the tested covariates, including obesity, was found to significantly influence the response to ANGIs alone or in various combinations with CCBs. In conclusion, obesity and corticosteroid therapy should be considered when initiating antihypertensive drug treatment in children with kidney disease as both may contribute to a reduced efficacy of the antihypertensive therapy.