Educational paper: Progression in chronic kidney disease and prevention strategies

Renin angiotensin aldosterone inhibitors in the treatment of proteinuria in children with congenital anomalies of the kidney and urinary tract: more evidence needed

INTRODUCTION

Congenital anomalies of the kidney and urinary tract (CAKUT) can be associated with proteinuria, possibly leading to a decline in kidney function. The aim of this review is to evaluate evidence on the efficacy of renin-angiotensin-aldosterone system inhibitors (RAASi) in children affected by CAKUT with proteinuria or chronic kidney disease (CKD).

AREAS COVERED

We conducted a bibliographic search between 1 December 2022 and 20 February 2023, including randomized controlled trials, case-control studies, observational studies, meta-analyses, and systematic reviews dealing with the efficacy of RAASi in reducing proteinuria and slowing the decline of kidney function in children.

EXPERT OPINION

RAASi are effective in reducing proteinuria and slowing CKD progression in many renal conditions; however, the efficacy of these drugs in patients affected by CAKUT with proteinuria is still unknown. While waiting for more evidence, when facing a child with CAKUT with isolated proteinuria or with proteinuria and CKD, a 6-12-month trial with RAASi with gradual increase to the maximal tolerated dose should be considered. If no improvement of proteinuria is obtained, the RAASi should be discontinued.

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

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

Kidney Transplant in a Pediatric Patient With Congenital Abnormalities of the Urinary Tract

Kidney transplant is the gold standard surgical treatment for patients with end-stage chronic kidney disease. Over the past decade, the frequency and prevalence of chronic kidney disease in children have been increasing, with it being a serious problem worldwide. Kidney transplant in Uzbekistan is still at an early stage, with the first successful kidney transplant performed in 2018. Here, we describe a successful kidney transplant in a pediatric female patient with a congenital abnormality of the urinary tract. The patient first showed symptoms at 7 years of age and was diagnosed with urolithic illness with inflammation of both kidneys. At presentation, she was 14 years of age with end-stage chronic kidney disease (diagnosed with stage 5 chronic kidney disease at age 13 years) caused by an anomaly in the development of the urinary tract. She received a kidney transplant from her mother as a living donor. There was vesicoureteral reflux on both sides and ureterohydronephrosis from 2 sides. On day 9 posttransplant, her creatinine level decreased from 0.40 to 0.066 mmol/L. Doppler ultrasonogram showed normal size and echogenicity of the graft, as well as adequate blood flow in the renal and iliac vessels. The patient was discharged on day 10 posttransplant in a satisfactory condition. In about 50% of cases, the cause of chronic renal failure in children is congenital anomalies of the urinary tract. The most common causes of hydronephrosis in newborns and children are vesicourethral reflux, which leads to the expansion of the urinary tract collecting system and the development of chronic renal failure. Early and accurate diagnosis and timely treatment of urinary tract abnormalities can reduce the incidence of end-stage chronic kidney disease in children.

Mechanism and restoration strategy of lysosomal abnormalities induced by urinary protein overload in proximal tubule epithelial cells

BACKGROUND

Persistent elevated concentrations of urinary protein can destroy proximal tubule epithelial cells (PTECs) by inducing lysosomal abnormalities, thereby aggravating PTEC damage and renal fibrosis. However, the specific mechanisms of these serial biochemical events and methods for treating or preventing PTEC damage upon proteinuria need further investigation.

RESULTS

In this study, electron microscopy and dual-labeled immunofluorescence analysis for identifying lysosome type revealed inadequate primary lysosome biogenesis and secondary lysosome accumulation in the PTECs of patients with minimal change nephrotic syndrome or membranous nephropathy who suffered from proteinuria. In vitro studies on HK-2 cells indicated that this abnormality was associated with decreased expression of transcription factor EB (TFEB). In contrast, TFEB overexpressing HK-2 cells under urinary protein overload exhibited significantly reduced accumulation of secondary lysosomes and increased proportion and quantity of primary lysosomes as indicated by dual-labeled immunofluorescence. Further, these cells could upregulate lysosomal degradation functions, as determined using Cathepsin L activity assays and flow cytometry for dye quenched-albumin.

CONCLUSIONS

These results indicate that abnormal TFEB expression is a key mechanism of lysosomal dyshomeostasis caused by protein overload in PTECs. TFEB is thus a potential therapeutic target for the treatment of urinary protein-related kidney disease.

The First Successful Kidney Transplant to a Child With Abnormality of Urinary Tract in Uzbekistan: Case Report

Kidney transplant has become a common surgical treatment for patients with end-stage chronic kidney disease. Chronic kidney disease in children is a major health problem in the world, with increasing incidence and prevalence. Uzbekistan is a young country, and surgeons were able to first perform kidney transplant surgery only in 2017. Here, we report a case of the first successful kidney transplant to a child in Uzbekistan. The patient, a 13-year-old boy with end-stage chronic kidney disease due to abnormal development of the urinary tract, received a kidney transplant from his father as a living donor. The diagnosis (abnormal development of the urinary tract, insufficiency of the vesicoureteral segment, and ureterohydronephrosis on both sides) was revealed when the boy was 4 years old, which resulted in vesicoureteral segment plastic surgery at diagnosis. Ten years later, the patient developed end-stage chronic kidney disease. At day 9 posttransplant, creatinine levels decreased from 0.53 to 0.043 mmol/L. Ultrasonography and Doppler imaging showed normal graft size and echogenicity and adequate flow in the renal and iliac vessels. The patient was discharged on posttransplant day 10 in good condition. For children with chronic kidney disease, the main cause is congenital abnormalities of the kidney and urinary tract. Kidney transplant in pediatric patients has become a common surgical procedure and is associated with high success rates. Early and accurate diagnosis and timely management of abnormal development of the urinary tract can reduce the rate of end-stage chronic kidney disease in children.

Patients with chronic kidney disease and diabetes mellitus: How is health care?

OBJECTIVE

To evaluate if the recommendations of appropriate health care for Chronic Kidney Disease (CKD) are implemented in patients with Diabetes Mellitus (DM) and Systemic Arterial Hypertension (SAH).

METHODS

This is a descriptive study conducted between January and March 2019 in Divinópolis, in the Brazilian state of Minas Gerais. Patients aged 18 years or older with CKD, DM and/or SAH were followed up at the municipal nephrology outpatient clinic. An interview was conducted using a structured questionnaire to assess care, which was categorized as adequate or inadequate, based on the health care recommendations of the national guidelines for care of patients with CKD.

RESULTS

42 participants with CKD participated in the study. All participants had SAH and 42.9% (n = 18) also had DM. It was evidenced that 81.0% (n = 34) of the individuals with CKD had adequate health care, especially among patients in earlier stages (3A and 3B) and those who progressed to renal replacement therapy. However, 80.0% (n = 8) of the participants in the intermediate stage (stage 4) were inadequately followed up by the nephrologist and multidisciplinary team.

CONCLUSIONS

Patients in intermediate stages do not receive follow-up with a multidisciplinary team at the recommended frequency. The preventive approach of the progression of renal disease in the intermediate stage in the studied municipality was not within the recommendations of the Ministry of Health.

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.

Does a multimethod approach improve identification of medication nonadherence in adolescents with chronic kidney disease?

BACKGROUND

Medical provider assessment of nonadherence is known to be inaccurate. Researchers have suggested using a multimethod assessment approach; however, no study has demonstrated how to integrate different measures to improve accuracy. This study aimed to determine if using additional measures improves the accurate identification of nonadherence beyond provider assessment alone.

METHODS

Eighty-seven adolescents and young adults (AYAs), age 11-19 years, with chronic kidney disease (CKD) [stage 1-5/end-stage renal disease (ESRD)] and prescribed antihypertensive medication, their caregivers, and 17 medical providers participated in the multisite study. Five adherence measures were obtained: provider report, AYA report, caregiver report, electronic medication monitoring (MEMS), and pharmacy refill data [medication possession ratio (MPR)]. Concordance was calculated using kappa statistic. Sensitivity, specificity, positive predictive power, and negative predictive power were calculated using MEMS as the criterion for measuring adherence.

RESULTS

There was poor to fair concordance (kappas = 0.12-0.54), with 35-61% of AYAs classified as nonadherent depending on the measure. While both providers and MEMS classified 35% of the AYAs as nonadherent, sensitivity (0.57) and specificity (0.77) demonstrated poor agreement between the two measures on identifying which AYAs were nonadherent. Combining provider report of nonadherence and MPR < 75% resulted in the highest sensitivity for identifying nonadherence (0.90) and negative predictive power (0.88).

CONCLUSIONS

Nonadherence is prevalent in AYAs with CKD. Providers inaccurately identify nonadherence, leading to missed opportunities to intervene. Our study demonstrates the benefit to utilizing a multimethod approach to identify nonadherence in patients with chronic disease, an essential first step to reduce nonadherence.

Progression of chronic kidney disease in children - role of glomerular hemodynamics and interstitial fibrosis

PURPOSE OF REVIEW

The aim of this review is to provide an overview of the current advances in the understanding of the mechanisms involved in the progression of chronic kidney disease (CKD) with emphasis on the role of glomerular hemodynamics and tubulointerstitial fibrosis.

RECENT FINDINGS

Despite the varied causes of CKD, the progressive destruction of renal tissue processes through a complex common pathway. Current studies have highlighted both the role of the abnormal intrarenal hemodynamics and of the activation of fibrogenic biochemical pathway in the replacement of normal renal structure by extracellular matrix and ultimately by fibrosis. Molecular markers with the potential to contribute to the detection of tubular cell damage and tubulointerstitial fibrosis in the kidney has been identified.

SUMMARY

There is a clear need to understand and elucidate the mechanisms of progression of CKD to develop efficient therapeutic strategies to halt decline of renal function in children.

Proteinuria and progression of pediatric chronic kidney disease: lessons from recent clinical studies

Proteinuria in children with chronic kidney disease (CKD) is common and its etiology differs from that in adults. How proteinuria influences the rate of progression of CKD has been analyzed in multiple retrospective clinical studies and more recently in a few prospective ones. In this review I summarize the results, strengths and weaknesses of each of these studies. The findings of several retrospective studies in children with CKD have confirmed what we have learned from adult studies on the association between proteinuria and worsening kidney function. Larger prospective clinical studies have examined the effects of proteinuria on the rate of decline of kidney function and the risk of end-stage kidney disease. They have also considered children with glomerular and, more importantly, the more common, congenital causes of CKD. Current studies have important strengths but also a few weaknesses that limit the validity of the conclusions which can be drawn. There is still a need for large clinical trials that focus primarily on studying the influence of proteinuria on kidney function and on finding remedies that delay progression.

Chronic kidney disease in children

Chronic kidney disease (CKD) is a major health problem worldwide. Although relatively uncommon in children, it can be a devastating illness with many long-term consequences. CKD presents unique features in childhood and may be considered, at least in part, as a stand-alone nosologic entity. Moreover, some typical features of paediatric CKD, such as the disease aetiology or cardiovascular complications, will not only influence the child's health, but also have long-term impact on the life of the adult that they will become. In this review we will focus on the unique issues of paediatric CKD, in terms of aetiology, clinical features and treatment. In addition, we will discuss factors related to CKD that start during childhood and require appropriate treatments in order to optimize health outcomes and transition to nephrologist management in adult life.

Chronic Kidney Disease in Children: Recent Update

The incidence of end stage of renal disease (ESRD) in US children age 0-19 years is 12.9 per million/year (2012). The economic and social burden of diagnosing, treating and preventing chronic kidney disease (CKD) in children and adults remains substantial. Advances in identifying factors that predict development of CKD and its progression, as well as advances in the management of co-morbid conditions including anemia, cardiovascular disease, growth, mineral and bone disorder, and neurocognitive function are discussed. Despite recent reports from retrospective registry data analysis and multi-center prospective studies which have significantly advanced our knowledge of CKD, and despite advances in the understanding of the pathogenesis, diagnosis and treatment of CKD much work remains to be done to improve the long term outcome of this disease.

MCP1 2518 A/G polymorphism affects progression of childhood focal segmental glomerulosclerosis

Monocyte chemoattractant protein-1 (MCP-1) is a highly specific chemokine for monocytes and plays roles in pathogenesis of various renal diseases. The aim of this study is to investigate the effect of MCP1 2518 A/G polymorphism on the incidence and clinical course of focal segmental glomerulosclerosis (FSGS) in children. MCP1 2518 A/G genotype was identified by PCR-RFLP in 60 biopsy-proven FSGS patients, 76 steroid sensitive nephrotic syndrome (SSNS) patients, and 96 healthy children. MCP-1 levels in urine and serum were measured by ELISA in all patients and the correlations of genotype with MCP-1 levels and clinical outcome were evaluated. The genotype frequencies for MCP1 were similar in all groups. The percentage of patients who develop chronic renal failure was higher in patients with AA allele compared to GA or GG alleles (46% vs. 35% respectively, p < 0.01, Odds ratio: 1.59). Serum MCP-1 levels were similar in all groups, whereas urinary MCP-1 levels of the patients with FSGS (1680 pg/mg creatinine) were significantly higher than that of patients with SSNS (365 pg/mg creatinine, p < 0.05) and healthy controls (348 pg/mg creatinine; p < 0.05). Urinary MCP-1 levels were correlated with the degree of proteinuria in FSGS group (r = 0.529, p = 0.016). Our results suggest that the AA genotype might be a risk factor for the progression of renal disease in FSGS and MCP1 genotyping may help the physicians to predict prognosis in these patients.

Progression of pediatric CKD of nonglomerular origin in the CKiD cohort

BACKGROUND AND OBJECTIVES

Congenital anomalies of the kidney and urinary tract and genetic disorders cause most cases of CKD in children. This study evaluated the relationships between baseline proteinuria and BP and longitudinal changes in GFR in children with these nonglomerular causes of CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Urine protein-to-creatinine ratio, casual systolic and diastolic BP (normalized for age, sex, and height), and GFR decline were assessed in the prospective CKD in Children cohort study.

RESULTS

A total of 522 children, median age 10 years (interquartile range, 7, 14 years) with nonglomerular CKD were followed for a median of 4.4 years. The mean baseline GFR in the cohort was 52 ml/min per 1.73 m(2) (95% confidence interval [95% CI], 50 to 54) and declined 1.3 ml/min per 1.73 m(2) per year on average (95%CI, 1.6 to 1.1). A 2-fold higher baseline urine protein-to-creatinine ratio was associated with an accelerated GFR decline of 0.3 ml/min per 1.73 m(2) per year (95% CI, 0.4 to 0.1). A 1-unit higher baseline systolic BP z-score was associated with an additional GFR decline of 0.4 ml/min per 1.73 m(2) per year (95% CI, 0.7 to 0.1). Among normotensive children, larger GFR declines were associated with larger baseline urine protein-to-creatinine ratios; eGFR declines of 0.8 and 1.8 ml/min per 1.73 m(2) per year were associated with urine protein-to-creatinine ratio <0.5 and ≥0.5 mg/mg, respectively. Among children with elevated BP, average GFR declines were evident but were not larger in children with higher levels of proteinuria.

CONCLUSIONS

Baseline proteinuria and systolic BP levels are independently associated with CKD progression in children with nonglomerular CKD.

Treatment Strategies to Prevent Renal Damage in Hypertensive Children

Hypertension secondary to chronic kidney disease prevails in earlier childhood and obesity-related primary hypertension in adolescence. Both are associated with a high risk of renal and cardiovascular morbidity. In children with chronic kidney disease, uncontrolled hypertension may accelerate progression to end-stage renal disease before adulthood is reached and increase a child’s risk of cardiac death a thousand-fold. Obesity-related hypertension is a slow and silent killer, and though early markers of renal damage are recognized during childhood, end-stage renal disease is a risk in later life. Renal damage will be a formidable multiplier of cardiovascular risk for adults in whom obesity and hypertension tracks from childhood. Management options to prevent renal damage will vary for these different target groups. This review provides a summary of the available renoprotective strategies in order to aid physicians involved in the care of this challenging group of children.

Remnant nephron physiology and the progression of chronic kidney disease

In chronic kidney disease, ongoing failure of individual nephrons leads to the progressive loss of renal function. This process results in part from a cellular and molecular response to injury that represents an attempt to maintain homeostasis but instead initiates a program that damages the nephron. As nephrons are lost, compensation by the remaining nephrons exacerbates glomerular pathophysiology. The delivery of excessive amounts of biologically active molecules to the distal nephron and tubulointerstitium generates inflammation and cellular dedifferentiation. Energy requirements of hyperfunctioning nephrons exceed the metabolic substrate available to the renal tubule, and inadequacy of the local vascular supply promotes hypoxia/ischemia and consequent acidosis and reactive oxygen species generation. In this way, mechanisms activated to maintain biological balance ultimately lead to demise of the nephron.