Metabolic syndrome in children with chronic kidney disease and after renal transplantation

Autosomal Dominant Polycystic Kidney Disease in Children and Adolescents: Assessing and Managing Risk of Progression

The clinical management of autosomal dominant polycystic kidney disease (ADPKD) in adults has shifted from managing complications to delaying disease progression through newly emerging therapies. Regarding pediatric management of the disease, there are still specific hurdles related to the management of children and adolescents with ADPKD and, unlike adults, there are no specific therapies for pediatric ADPKD or stratification models to identify children and young adults at risk of rapid decline in kidney function. Therefore, early identification and management of factors that may modify disease progression, such as hypertension and obesity, are of most importance for young children with ADPKD. Many of these risk factors could promote disease progression in both ADPKD and chronic kidney disease. Hence, nephroprotective measures applied early in life can represent a window of opportunity to prevent the decline of the glomerular filtration rate especially in young patients with ADPKD. In this review, we highlight current challenges in the management of patients with pediatric ADPKD, the importance of early modifying factors in disease progression as well as the gaps and future perspectives in the pediatric ADPKD research field.

Malnutrition and immune cell subsets in children undergoing kidney transplantation

BACKGROUND

Malnutrition, including obesity and undernutrition, among children is increasing in prevalence and is common among children on renal replacement therapy. The effect of malnutrition on the pre-transplant immune system and how the pediatric immune system responds to the insult of both immunosuppression and allotransplantation is unknown. We examined the relationship of nutritional status with post-transplant outcomes and characterized the peripheral immune cell phenotypes of children from the Immune Development of Pediatric Transplant (IMPACT) study.

METHODS

Ninety-eight patients from the IMPACT study were classified as having obesity, undernutrition, or normal nutrition-based pre-transplant measurements. Incidence of infectious and alloimmune outcomes at 1-year post-transplantation was compared between nutritional groups using Gray's test and Fine-Gray subdistribution hazards model. Event-free survival was estimated by Kaplan-Meier method and compared between groups. Differences in immune cell subsets between nutritional groups over time were determined using generalized estimating equations accounting for the correlation between repeated measurements.

RESULTS

We did not observe that nutritional status was associated with infectious or alloimmune events or event-free survival post-transplant. We demonstrated that children with obesity had distinct T-and B-cell signatures relative to those with undernutrition and normal nutrition, even when controlling for immunosuppression. Children with obesity had a lower frequency of CD8 Tnaive cells 9-month post-transplant (p < .001), a higher frequency of CD4 CD57 + PD1- T cells, and lower frequencies of CD57-PD1+ CD8 and CD57-PD1- CD8 T cells at 12-month transplant (p < .05 for all).

CONCLUSIONS

Children with obesity have distinct immunophenotypes that may influence the tailoring of immunosuppression.

Relation between obesity-related comorbidities and kidney function estimation in children

BACKGROUND

The current childhood obesity pandemic is likely to result in an increased risk of chronic kidney disease (CKD) later in life. Correlations between obesity-related comorbidities and kidney function can be found, but it is unclear to what extent this is caused by bias due to different mathematical forms of the estimated glomerular filtration rate (eGFR) equations. The present study aimed to analyze correlations between obesity-related comorbidities and different eGFR equations and to investigate whether rescaled serum creatinine (SCr/Q) for sex and age or height might be an alternative biomarker for kidney function estimation.

METHODS

This cross-sectional cohort study included 600 children with overweight and obesity. Mean age was 12.20 ± 3.28 years, 53.5% were female, and mean BMI z-score was 3.31 ± 0.75. All children underwent a comprehensive assessment that included anthropometrical and blood pressure measurements, laboratory examination, air displacement plethysmography, and polysomnography. Qage and Qheight polynomials were used to rescale SCr and multiple creatinine-based eGFR equations were compared.

RESULTS

SCr/Q and almost all GFR estimations significantly correlated with a waist-to-hip ratio, fat mass, homeostasis model assessment for insulin resistance, and triacylglyceride, HDL cholesterol, alanine transaminase, and serum uric acid concentrations. Multiple correlations, however, were not confirmed by all equations, which suggests dependency on the mathematical form of the different eGFR equations.

CONCLUSIONS

Correlations between obesity-related comorbidities and creatinine-based eGFR are present in children with overweight and obesity, but depend to a large extent on the eGFR equation of choice. SCr/Q might be an alternative biomarker for assessing correlations between obesity-related comorbidities and kidney function in children with overweight and obesity. A higher resolution version of the Graphical abstract is available as Supplementary information.

Assessment of Cystatin-C level in Newly Diagnosed Iraqi Children with Nephritic Syndrome

BACKGROUND: Nephritic syndrome (NS) is a common kidney disease in children that causes protein leakage from the blood into the urine due to glomerular injury. AIM: The aim of this research was to determine the level of Cystatin-C (CysC) and other biochemical parameters in newly diagnosed NS children in Iraq. PATIENTS AND METHODS: Ninety Iraqi children divided into: 50 children with newly diagnosed NS (28 boys and 22 girls) aged between (4 and 16) years, and 40 healthy control children (20 boys and 20 girls) aged between (5 and 16) years, who were attending Al-Yarmouk Teaching Hospital, Baghdad. RESULTS: There was a significant increase in blood urea, serum total cholesterol (S.TC), and serum low density lipoprotein (S.LDL) and a significant decreased of serum creatinine (S. creatinine), protein/creatinine ratio, serum total bilirubin, serum albumin, and serum high density lipoprotein, while a highly significant increased (p < 0.001) of CysC levels in children with newly diagnosed NS when compared with control group. A significant positive correlation between CysC level versus systolic blood pressure, body mass index, diastolic blood pressure, S.TC, S. LDL cholesterol (S.LDL-C), S. Total Bilirubin, S. Albumin, S. Total protein, and B. urea, while a significant negative correlation was found between CysC level versus serum low density lipoprotein cholesterol and estimated glomerular filtration rate in children with newly diagnosed NS. CONCLUSION: It may come to the conclusion that CysC can be the best predictor of overall efficacy than creatinine and in the diagnosis of any damage to the kidney in children with NS.

Kidney Adaptations Prevent Loss of Trace Elements in Wistar Rats with Early Metabolic Syndrome

Metabolic syndrome (MetS) represents a cluster of related metabolic abnormalities, including central obesity, hypertension, dyslipidemia, hyperglycemia, and insulin resistance. These metabolic derangements present significant risk factors for chronic kidney disease that carries to loss of essential micronutrients, which accelerates comorbidity apparition. The work aimed was to evaluate the trace element homeostasis regarding morphological adaptations and renal function in MetS early-onset. Fifty male Wistar rats were divided into two groups: (a) control group and (b) hypercaloric diet group that developed MetS early-onset after 3 months. Classical zoometric parameters do not show changes; however, biochemical modifications were observed such as hyperglycemia, protein glycation, insulin resistance, dyslipidemia, hyperinsulinemia, and hypoadiponectinemia. MetS early-onset group observed renal structural modifications, but no functional changes. The structural modifications observed were minimal glomerular injury, glomerular basement membrane thickening, as well as mesangial and tubular cells that showed growth and proliferation. In serum and kidney (cortex and medulla), the concentrations of Zn, Fe, Cr, Mg, Mn, Cu, Co, and Ni were no differences between the experimental groups, but excretory fractions of these were lower in the hypercaloric diet group. In conclusion, MetS early-onset coexist renal structural modification and a hyperreabsorptive activity of essential trace elements that avoid its loss; thus, the excretory fraction of oligo-elements could be used a biomarker of early renal injury caused by metabolic diseases in the clinical practice.

Left ventricular stiffness in paediatric patients with end-stage kidney disease

BACKGROUND

We tested the hypothesis that myocardial stiffness is altered in paediatric patients with end-stage kidney disease (ESKD) and explored its association with clinical parameters of chronic kidney disease (CKD).

METHODS

Thirty-five patients with ESKD (16 males) aged 17.5 ± 3 years old, 18/35 of whom were receiving dialysis and 17 post kidney transplant, were studied. Left ventricular (LV) myocardial stiffness was determined by measurement of diastolic wall strain (DWS) and stiffness index (SI), while LV diastolic function was interrogated by pulsed-wave and tissue Doppler echocardiography.

RESULTS

Compared with available literature data, both dialysis and transplanted patients had significantly lower DWS and greater SI, reduced transmitral early (E) to late diastolic velocity ratio and septal and lateral mitral annular early (e') diastolic velocities, and greater septal and lateral E/e' ratios (all p < 0.05). Multivariate analysis revealed that z score of diastolic blood pressure (β = 0.43, p = 0.004) and the duration of renal replacement therapy (β = 0.55, p < 0.001) were significant determinants of LV SI. Subgroup analysis in post-transplant patients showed z score of diastolic blood pressure (β = 0.54, p = 0.025) remained as a significant determinant of LV SI.

CONCLUSION

Increased LV myocardial stiffness is evident in paediatric dialysis and transplanted patients with ESKD, and is associated with blood pressure and duration of renal replacement therapy.

Physical fitness and health-related quality of life in pediatric renal transplant recipients: An interventional trial with active video gaming

BACKGROUND

Pediatric renal transplant recipients are at increased risk for cardiovascular diseases, one contributing factor is reduced cardiorespiratory fitness. The purpose was to evaluate cardiorespiratory fitness, motor coordination, muscle strength, daily physical activity, and health-related quality of life and to find out, if active video gaming is effective for improving these items in this patient population.

METHODS

Twenty renal transplant recipients (13.5 ± 3.4 years) and 33 matched healthy controls (13.1 ± 3.2 years) performed a spiroergometry, a motor coordination test, and a maximal handgrip strength test. Quality of life was determined with a validated questionnaire, and daily physical activity was recorded with a physical activity monitor. Thirteen patients (12.9 ± 3.4 years) participated in a 6-week home-based exergaming intervention (3×/week for 30 minutes) and repeated all tests after that.

RESULTS

The renal transplant recipients exhibited a substantial impairment compared with the controls in peak oxygen consumption (-31%, P < .001), motor competence (-44%, P < .001), daily physical activity (-33%, P = .001), and quality of life (-12%, P = .017). Handgrip strength was similar in both groups. Despite of low compliance in the intervention group, steps per hour were significantly increased after 6 weeks of exergaming (+31%, P = .043); however, all other measures remained unchanged.

CONCLUSION

Cardiorespiratory fitness, motor competence, and quality of life are reduced in pediatric renal transplant recipients. Home-based exergaming is not appropriate to improve these items, probably due to a substantially impaired motor competence. However, it provided a stimulus for an increased daily physical activity.

Depression and neurocognitive dysfunction in pediatric and young adult chronic kidney disease

BACKGROUND

Depression affects 7-35% of children with chronic kidney disease (CKD), and in adults with CKD, the presence of depression links to poorer medical outcomes, social functioning difficulties, and neurocognitive impairments. The relationship between depression and neurocognitive function in youth with CKD is unclear. We sought to identify factors associated with depression in youth with CKD and to determine whether depression affects neurocognitive performance.

METHODS

We conducted cross-sectional analyses in 71 CKD and 64 control participants aged 8 to 25 years who completed depression inventories and neurocognitive assessments as part of the Neurocognitive Assessment and Magnetic Resonance Imaging Analysis of Children and Young Adults with CKD Study. In the CKD group, multivariable logistic regression analysis determined associations between clinical and demographic factors and depression. In the full study cohort, multivariable linear regression analyses, including an interaction term between CKD status and depression evaluated the effect of depression on 11 neurocognitive outcome domains.

RESULTS

Obesity significantly associated with depression in the CKD group (OR 10.25, P = 0.01). In adjusted analyses, depressed youth with CKD scored worse than non-depressed CKD participants by 0.6-1.0 standard deviations in 5 neurocognitive domains: attention, visual memory, visual-spatial, visual working memory, and problem solving.

CONCLUSIONS

CKD youth with obesity are more likely to be depressed, and those who are depressed exhibit worse neurocognitive performance. Depression may represent a therapeutic target to improve neurocognitive performance in youth with CKD.

Cardiometabolic correlates of sleep-disordered breathing in renal transplant children

Sleep-disordered breathing, a prevalent condition among adult renal transplant (RTx) recipients, has become an established independent risk factor of MetS, and furthermore, it might contribute to increased CV risk. Despite the proven correlations in adults, there is a lack of evidence for its significance in the pediatric RTx population. In this study, we aimed at assessing the prevalence and the clinical correlates of SDB in RTx children. Data of 13 patients (age [mean ± SD]: 14.2 ± 2.7 years) were analyzed. SDB was evaluated by PSG, as severity score OAHI was applied. Carbohydrate metabolism was characterized by OGTT, whereas CV status was studied by ABPM. Three composite end-points were calculated as sum of z-scores: daytime systolic and diastolic BP; nighttime systolic and diastolic BP; and glucose and insulin levels at 120 minutes. Eight patients (61.5%) were diagnosed with SDB of whom five patients (38.5%) had moderate or severe SDB. In linear regression analysis, OAHI during REM was associated with the CV variables (daytime BP P = 0.032, ß = 0.748; nighttime BP P = 0.041, ß = 0.715), and the correlations remained significant after adjustments for BMI. However, we did not confirm a significant association with the metabolic variables. The prevalence of SDB was high, and its severity during REM was a predictor of the BP suggesting that RTx children with SDB might be at risk of developing CV complications, especially HTN similarly to adults.

Cardiovascular Disease in Children and Adolescents With Chronic Kidney Disease

The lifespan of children with advanced chronic kidney disease (CKD), although improved over the past 2 decades, remains low compared with the general pediatric population. Similar to adults with CKD, cardiovascular disease accounts for a majority of deaths in children with CKD because these patients have a high prevalence of traditional and uremia-related risk factors for cardiovascular disease. The cardiovascular alterations that cause these terminal events begin early in pediatric CKD. Initially, these act to maintain hemodynamic homeostasis. However, as the disease progresses, these modifications are unable to sustain cardiovascular function in the long term, leading to left ventricular failure, depressed cardiorespiratory fitness, and sudden death. In this review, we discuss the prevalence of the risk factors associated with cardiovascular disease in pediatric patients with CKD, the pathophysiology that stimulates these changes, the cardiac and vascular adaptations that occur in these patients, and management of the cardiovascular risk in these patients.

Non-immunologic allograft loss in pediatric kidney transplant recipients

Non-immunologic risk factors are a major obstacle to realizing long-term improvements in kidney allograft survival. A standardized approach to assess donor quality has recently been introduced with the new kidney allocation system in the USA. Delayed graft function and surgical complications are important risk factors for both short- and long-term graft loss. Disease recurrence in the allograft remains a major cause of graft loss in those who fail to respond to therapy. Complications of over immunosuppression including opportunistic infections and malignancy continue to limit graft survival. Alternative immunosuppression strategies are under investigation to limit calcineurin inhibitor toxicity. Finally, recent studies have confirmed long-standing observations of the significant negative impact of a high-risk age window in late adolescence and young adulthood on long-term allograft survival.

The prevalence and outcome of children with failure to thrive after pediatric kidney transplantation

BACKGROUND

Prior to transplantation, effects of advanced CKD contribute to malnutrition and impaired growth. After transplant, children are expected to thrive, however, in a subset of transplant recipients this does not occur. Factors associated with post-transplant FTT are poorly understood.

OBJECTIVE

A retrospective cohort study was conducted to determine factors associated with FTT and association of FTT with infections and hospitalizations.

METHODS

Records of 119 children transplanted between 2005 and 2016 were reviewed. FTT was defined by ≥2 of the following post-transplant criteria: (a) low BMI or deceleration in BMI z-score, (b) poor growth velocity, and (c) chronic hypoalbuminemia at 1 or 3 years post-transplant. Association of FTT with deceased donor transplant, de novo DSA, intolerance to MMF, anemia, vitamin D deficiency, and CIC was investigated by logistic regression. Poisson regression was used to identify outcomes associated with FTT.

RESULTS

Low pre-transplant BMI and post-transplant CIC dependence were independently associated with FTT after transplant. Odds of FTT at 1 year post-transplant decreased by 0.5 for each 1 unit increase in pre-transplant BMI z-score. Requirement for CIC conferred 3.8 and 7.8 higher odds of FTT at 1 and 3 years. Patients with FTT had 2.7 and 2.6 times infections and hospitalizations during the first year, and 4.2 and 4.3 times infections and hospitalizations over 3 years post-transplant.

CONCLUSIONS

Children with low BMI prior to transplant and those requiring CIC after transplant are at increased risk for post-transplant FTT. FTT is associated with adverse outcomes, evidenced by increased infections and hospitalizations.

Cardiometabolic Risk Factors, Metabolic Syndrome, and Chronic Kidney Disease Progression in Children

OBJECTIVE

To estimate the prevalence of metabolic syndrome (MetS) and examine its association with chronic kidney disease progression in children enrolled in the Chronic Kidney Disease in Children study.

STUDY DESIGN

MetS was defined as being overweight or obese and having ≥2 cardiometabolic risk factors (CMRFs). Incidence and prevalence of MetS were assessed using pairs of visits approximately 2 years apart.

RESULTS

A total of 799 pairs of person-visits (contributed by 472 children) were included in the final analysis. Of these, 70% had a normal body mass index (BMI), 14% were overweight, and 16% were obese. At the first visit, the prevalence of MetS in the overweight group was 40% and in the obese group was 60%. In adjusted models, annual percent estimated glomerular filtration rate decline in those who had normal BMI and incident or persistent multiple CMRFs or those with persistent MetS was -6.33%, -6.46%, and -6.08% (respectively) compared with children who never had multiple CMRFs (-3.38%, P = .048, .045, and .036, respectively). Children with normal BMI and incident multiple CMRFs and those with persistent MetS had approximately twice the odds of fast estimated glomerular filtration rate decline (>10% per year) compared with those without multiple CMRFs and normal BMI.

CONCLUSION

Children with chronic kidney disease have a high prevalence of MetS. These children as well as those with normal BMI but multiple CMRFs experience a faster decline in kidney function.

Small effort, high impact: Focus on physical activity improves oxygen uptake (VO2peak ), quality of life, and mental health after pediatric renal transplantation

This study estimates the effects on peak oxygen uptake (VO2 peak ), QoL, and mental health after the introduction of an adjusted post-transplant follow-up program, that is, early physiotherapy and focus on the importance of physical activity. VO2 peak was measured by a treadmill exercise test in 20 renal-transplanted children on the adjusted post-transplant follow-up and compared with a group of 22 patients investigated in a previously, before the implementation of our new follow-up routines. PedsQL and The Strengths and Difficulties Questionnaire (SDQ) were used to assess QoL and mental health in 45 patients on the new as compared to 32 patients on the previous follow-up strategy. The patients exposed to early physiotherapy and a higher focus on physical activity had significantly higher VO2 peak (44.3 vs 33.5 mL kg-1  min-1 , P = .031) in addition to improved QoL (P = .003) and mental health scores (P = .012). The cardiovascular risk profile was similar in both groups aside from significantly higher triglycerides in the present cohort. Small efforts as early physiotherapy and increased focus on physical activity after pediatric renal transplantation have significant impact on cardiorespiratory fitness, QoL, and mental health. The importance of physical activity should therefore be emphasized in follow-up programs.

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.

Paediatric obesity and renal transplantation: current challenges and solutions

The increased incidence of obesity in the paediatric population poses significant challenges to renal transplantation. Whilst the body mass index appears to be widely used as a measure of obesity in adults, there are no standardised definitions in the paediatric population, making comparative analyses difficult. In the paediatric transplant population, obesity is associated with an increased incidence of surgical complications, diabetes, hyperlipidaemia and cardiovascular morbidity, leading to diminished graft function and impacting patient and graft survival. Management of obesity in renal transplantation requires multiple interventions starting with life-style and behavioural modification combined with medical and possibly surgical therapies, representing a unique challenge in the childhood setting. In this review we discuss the current challenges of obesity and potential solutions in the setting of paediatric transplantation.

Long-term effects of paediatric kidney transplantation

Renal transplantation in paediatric patients usually provides excellent short-term and medium-term results. Early diagnosis of chronic kidney disease and active therapy of end-stage renal disease before and after transplantation enables the majority of children to grow and develop normally. The adverse effects of immunosuppressive medication and reduced graft function might, however, hamper long-term outcomes in these patients and can lead to metabolic complications, cardiovascular disease, reduced bone health, and malignancies. The neurocognitive development and quality of life of paediatric transplant recipients largely depend on the primary diagnosis and on graft function. Poor adherence to immunosuppression is an important risk factor for graft loss in adolescents, and controlled transition to adult care is of utmost importance to ensure a continued normal life. In this Review, we discuss the outcomes and long-term effects of renal transplantation in paediatric recipients, including consequences on growth, development, bone, metabolic, and cardiovascular disorders. We discuss the key problems in the care of paediatric renal transplant recipients and the remaining challenges that should be the focus of future research.

Paediatrics, insulin resistance and the kidney

Systemic insulin resistance is becoming more prevalent in the young due to modern lifestyles predisposing to the metabolic syndrome and obesity. There is also evidence that there are critical insulin-resistant phases for the developing child, including puberty, and that renal disease per se causes systemic insulin resistance. This review considers the factors that render children insulin resistant, as well as the accumulating evidence that the kidney is an insulin-responsive organ and could be affected by insulin resistance.