Growth and maturation improvement in children on renal replacement therapy over the past 20 years

Multidisciplinary approach to optimizing long-term outcomes in pediatric kidney transplant recipients: multifaceted needs, risk assessment strategies, and potential interventions

The post-transplant course of pediatric kidney transplant recipients is marked by a myriad of challenges, encompassing medical complications, recurrent hospitalizations, physical and dietary restrictions, and mental health concerns such as depression, anxiety, and post-traumatic stress disorder. Moreover, pediatric recipients are at risk of neurodevelopmental impairment, which may result in neurocognitive deficits and pose significant psychosocial obstacles. Addressing these multifaceted demands necessitates a multidisciplinary approach to pediatric kidney transplant care. However, the existing literature on the effective implementation of such a model remains scarce. This review examines the psychosocial and neurodevelopmental challenges faced by pediatric kidney transplant recipients and their families, discussing their impact on long-term transplant outcomes. Furthermore, it provides insights into risk assessment strategies and potential interventions within a multidisciplinary framework, aiming to enhance patient care and optimize post-transplant outcomes.

Morphological changes and their associations with clinical parameters in children with nephropathic cystinosis and chronic kidney disease prior to kidney replacement therapy over 25 years

BACKGROUND

Infantile nephropathic cystinosis (INC) is a rare lysosomal storage disorder, mostly and often firstly affecting the kidneys, together with impaired disharmonious growth and rickets, eventually resulting in progressive chronic kidney disease (CKD). With the introduction of cysteamine therapy, most pediatric patients reach adulthood with no need for kidney replacement therapy. Still, detailed changes in INC patients' clinical and morphological presentation over the past decades have not yet been thoroughly investigated.

METHODS

Two groups with a respective total of 64 children with INC and 302 children with CKD, both treated conservatively and aged 2 to 18 years, were prospectively observed in the time span from 1998 to 2022 with 1186 combined annual clinical and morphological examinations clustered into two measurement periods (1998 to 2015 and ≥ 2016).

RESULTS

In INC patients, thoracic proportion indices remained markedly increased, whereas body fat stores remained decreased over the past 25 years (+ 1 vs. below ± 0 z-score, respectively). Their CKD peers presented with overall improved growth, general harmonization of body proportions, and improved body fat stores, while INC patients only presented with an isolated significant increase in leg length over time (∆0.36 z-score). eGFR adjusted for age did not significantly change over the past 25 years in both groups. Alkaline phosphatase (ALP) showed a significant decrease in CKD patients over time, while remaining above normal levels in INC patients.

CONCLUSIONS

Disproportionate thoracic shape and impaired body fat stores remain the most characteristic morphological traits in INC patients over the past 25 years, while causal mechanisms remain unclear.

Puberty Today, Gone Tomorrow: Transient Refractory Central Precocious Puberty in a Toddler with End-Stage Kidney Disease

INTRODUCTION

The onset of puberty is typically delayed in children with chronic kidney disease (CKD), with only three reported cases of precocious puberty in boys with CKD.

CASE PRESENTATION

We report the case of a boy with end-stage kidney disease secondary to posterior urethral valves who, while undergoing peritoneal dialysis, presented at 17 months with central precocious puberty characterized by clinical signs of testicular and penile enlargement, pubic hair, and acne; rapid linear growth with advanced bone age; and pubertal luteinizing hormone (LH) and testosterone levels. Monthly leuprolide injections were commenced at 24 months with no pubertal or biochemical suppression thereafter, along with continued rapid bone-age advancement through 32 months. He then received a deceased-donor kidney transplant at 33 months of age, with good graft function. Within 2 months, he was noted to have prepubertal GnRH-stimulated LH and testosterone levels. Leuprolide injections were discontinued at that time with no further progression of puberty. The patient is now 48 months old with minimal further bone-age advancement and consistently prepubertal LH and testosterone levels.

CONCLUSION

Our case demonstrates the development of precocious puberty due to premature activation of the hypothalamic-pituitary-testicular axis, presumably secondary to uremia and/or disordered renal clearance of gonadotropins, which was refractory to standard management with a gonadotropin-releasing hormone agonist, perhaps due to excessively rapid removal by peritoneal dialysis and/or the uremic state itself. Kidney transplantation led to a correction of uremia and a return to the prepubertal state.

Get to the heart of pediatric kidney transplant recipients: Evaluation of left- and right ventricular mechanics by three-dimensional echocardiography

Background

Kidney transplantation (KTX) markedly improves prognosis in pediatric patients with end-stage kidney failure. Still, these patients have an increased risk of developing cardiovascular disease due to multiple risk factors. Three-dimensional (3D) echocardiography allows detailed assessment of the heart and may unveil distinct functional and morphological changes in this patient population that would be undetectable by conventional methods. Accordingly, our aim was to examine left- (LV) and right ventricular (RV) morphology and mechanics in pediatric KTX patients using 3D echocardiography.

Materials and methods

Pediatric KTX recipients (n = 74) with median age 20 (14–26) years at study enrollment (43% female), were compared to 74 age and gender-matched controls. Detailed patient history was obtained. After conventional echocardiographic protocol, 3D loops were acquired and measured using commercially available software and the ReVISION Method. We measured LV and RV end-diastolic volumes indexed to body surface area (EDVi), ejection fraction (EF), and 3D LV and RV global longitudinal (GLS) and circumferential strains (GCS).

Results

Both LVEDVi (67 ± 17 vs. 61 ± 9 ml/m2; p < 0.01) and RVEDVi (68 ± 18 vs. 61 ± 11 ml/m2; p < 0.01) were significantly higher in KTX patients. LVEF was comparable between the two groups (60 ± 6 vs. 61 ± 4%; p = NS), however, LVGLS was significantly lower (−20.5 ± 3.0 vs. −22.0 ± 1.7%; p < 0.001), while LVGCS did not differ (−29.7 ± 4.3 vs. −28.6 ± 10.0%; p = NS). RVEF (59 ± 6 vs. 61 ± 4%; p < 0.05) and RVGLS (−22.8 ± 3.7 vs. −24.1 ± 3.3%; p < 0.05) were significantly lower, however, RVGCS was comparable between the two groups (−23.7 ± 4.5 vs. −24.8 ± 4.4%; p = NS). In patients requiring dialysis prior to KTX (n = 64, 86%) RVGCS showed correlation with the length of dialysis (r = 0.32, p < 0.05).

Conclusion

Pediatric KTX patients demonstrate changes in both LV and RV morphology and mechanics. Moreover, the length of dialysis correlated with the contraction pattern of the right ventricle.

[Chronic kidney disease and growth failure: Efficacy of growth hormone treatment]

Growth failure is a frequent complication observed in children with chronic kidney disease (CKD) and correlated to increased morbidity and mortality. To achieve a normal growth in children with CKD remains challenging for pediatric nephrologists. Growth failure in the setting of pediatric CKD is multifactorial and related to an impaired sensitivity to growth hormone and to a deficiency of IGF1 (insulin-like growth factor 1). Growth failure management has improved during the last two decades and consists of correcting any nutritional and metabolic abnormalities, of an improvement of dialysis for children on end-stage renal disease, and of an administration of a supraphysiologic dose of recombinant growth hormone to overcome GH insensitivity. This article summarizes the causes, outcomes and assessment tools of growth in children with CKD as well as the management of recombinant growth hormone.

Epidemiology of biopsy-proven glomerular diseases in Chinese children: A scoping review

Background

Glomerular disease is the leading cause of chronic kidney disease globally. No scoping review reports have focused on China's spectrum of glomerular diseases in children. This study aimed to systematically identify and describe retrospective studies on pediatric glomerular disease based on available data on sex, age, study period, and region.

Methods

Six databases were systematically searched for relevant studies from initiation to December 2021 in PubMed, Embase, Web of Science, Global Health Library, Wangfang Database, and CNKI.

Results

Thirty-four studies were identified in the scoping review, including 40,430 patients with biopsy-proven diagnoses. The proportion of boys was significantly higher than that of girls. In this study, 28,280 (70%) cases were primary glomerular disease, 10,547 (26.1%) cases were diagnosed as secondary glomerular disease, and 1146 (2.8%) cases were hereditary glomerular disease. Minimal change disease is the most common glomerular disease among children in China, followed by mesangial proliferative glomerulonephritis, IgA nephropathy, and purpura nephritis. We observed increments in glomerular diseases in periods 2 (2001-2010) and 3 (2011-2021). The proportion of major glomerular diseases varies significantly in the different regions of China.

Conclusion

The spectrum of pediatric glomerular diseases varied across sex, age groups, study periods, and regions, and has changed considerably over the past 30 years.

Human papillomavirus-related cancer risk for solid organ transplant recipients during adult life and early prevention strategies during childhood and adolescence

Malignancies are among the top three causes of patient death in pediatric and adult kidney transplant (KT) recipients. Solid organ transplant (SOT) recipients, including KT individuals, experience more cancer compared with the general population, including human papillomavirus (HPV)-related anogenital and oropharyngeal cancers. This article describes the epidemiology, pathophysiology and natural history of the HPV infection in both the general population and in SOT recipients, as well as its role in the development of HPV-related pre-cancerous lesions and cancers. Emphasis is given to the primary prevention strategy, HPV vaccination in SOT recipients, and its particularities compared with the general population. Secondary prevention strategies in SOT recipients are discussed and compared with the general population, highlighting cervical cancer screening needs within SOT populations. The article emphasizes how these primary and secondary HPV prevention strategies applied during childhood and adolescence by the pediatric transplant professionals, can lower the burden of HPV-related cancers for SOT recipients in subsequent years, during their adult life.

Estrogen replacement therapy: effects of starting age on final height of girls with chronic kidney disease and short stature

INTRODUCTION

We investigated the age of starting Estrogen replacement therapy as a key parameter for reaching near normal Final Height (FH) in Chronic Kidney Disease (CKD) girls with growth retardation.

METHOD

This open label, quasi-experimental designed and matched controlled clinical trial was performed on CKD girls with short stature and later onset of puberty or delayed puberty according to clinical and laboratory investigations. Participants of group 1 and 2 had been treated with Growth Hormone (GH), and Ethinyl Estradiol (EE). EE was administered from 11 and 13 yrs. old in groups 1 and 2 respectively. Group 3 was selected from patients that did not accept to start GH or EE till 15 years old. The effect of the age of starting EE on FH, GH therapy outcomes, bone density, and calcium profile were evaluated.

RESULT

Overall, 16, 22, and 21 patients were analyzed in groups 1, 2, and 3 respectively. Mean Mid-Parental Height (MPH) had no significant difference between the 3 groups. GH therapy significantly enhanced mean FH in groups 1 and 2 in comparison with group 3 (β = - 4.29, p < 0.001). Also, multivariable backward linear regression illustrated significant negative association between FH and age of starting EE (β = 0.26, p < 0.001). Mean Para Thyroid Hormone (PTH), mean femoral and lumbar bone density were significantly enhanced after GH and EE therapy (p value: < 0.001).

CONCLUSION

We recommend starting EE from 11 yrs. old in CKD short stature girls who have no clinical and laboratory sign of sexual maturity at 11 yrs. to enhance the cost effectiveness of GH therapy.

Exogenous growth hormone functionally alleviates glucocorticoid-induced longitudinal bone growth retardation in male rats by activating the Ihh/PTHrP signaling pathway

Glucocorticoid (GC)-induced longitudinal bone growth retardation is a common and severe adverse effect in pediatric patients receiving GC immunosuppressive therapy. Molecular mechanisms underlying GC-induced growth inhibition are unclear. GC withdrawal following short-term high-dose use is common, including in the immediate post-transplant period. However, whether skeleton growth recovery is sufficient or whether growth-promoting therapy is required following GC withdrawal is unknown. The aim of this study was to investigate the effect of exogenous growth hormone (GH) on growth plate impairment in GC-induced longitudinal bone growth retardation. Here, apoptotic chondrocytes in the hypertrophic layer of growth plates increased whereas Indian Hedgehog (Ihh) and Parathyroid Hormone Related Peptide (PTHrP) protein levels in the growth plate decreased following GC exposure. The hypertrophic zone of the growth plate expanded following GC withdrawal. Subcutaneously injected GH penetrated the growth plate and modified its organization in rats following GC withdrawal. Ihh and PTHrP expression in GC-induced apoptotic chondrocytes decreased in vitro. GH promoted chondrocyte proliferation by activating Ihh/PTHrP signaling. Downregulating Ihh using specific siRNAs increased chondrocyte apoptosis and inhibited PTHrP, Sox9, and type II collagen (Col2a1) protein expression. GH inhibited apoptosis of Ihh-deficient growth plate chondrocytes by upregulating PTHrP, Sox9, and Col2a1 expression. Thus, reversal of the effect of GC on growth plate impairment following its withdrawal is insufficient, and exogenous GH provides growth plate chondral protection and improved longitudinal growth following GC withdrawal by acting on the Ihh/PTHrP pathway.

Human papillomavirus infection-related cancer risk for kidney transplant recipients during adult life can be reduced by vaccination during childhood and adolescence

Malignancies are found between the first three reasons of mortality in pediatric and adult kidney transplant recipients, who overall have disproportionately higher rates of cancer compared to the general population, including human papillomavirus (HPV)-related genital, anal and oropharynx region cancers. Therefore, preventing HPV in this patient population is extremely important. HPV-vaccine was demonstrated to prevent HPV infection in individuals with intact immune systems. In addition, recent data reported less precancerous HPV lesions and cervical cancers with use of HPV vaccine. Since HPV is a sexually transmitted virus that is typically acquired shortly after the onset of sexual activity, it is best to administer the HPV vaccine immunization prior to the onset of sexual activity. This article reviews the epidemiology and pathophysiology of the HPV infection, as well as its role in the development of HPV-related pre-cancerous lesions and cancers in both general population and kidney transplant recipients. The focus is on the most effective primary prophylactic strategy, which is the HPV vaccination. The particularities of HPV vaccination strategies in kidney transplant recipients are compared to the general population. In addition, the article analyzes the various causes of suboptimal HPV immunization rates in kidney transplant candidates and recipients and discusses vaccination optimization strategies that can be applied during childhood and adolescence to reduce the burden of HPV-related disease states and cancer among adult kidney transplant recipients.

Growth hormone treatment in the pre-transplant period is associated with superior outcome after pediatric kidney transplantation

BACKGROUND

Recombinant human growth hormone (rhGH) is frequently used for treatment of short stature in children with chronic kidney disease (CKD) prior to kidney transplantation (KT). To what extent this influences growth and transplant function after KT is yet unknown.

METHODS

Post-transplant growth (height, sitting height, leg length) and clinical parameters of 146 CKD patients undergoing KT before the age of 8 years, from two German pediatric nephrology centers, were prospectively investigated with a mean follow-up of 5.56 years. Outcome in patients with (rhGH group) and without (non-prior rhGH group) prior rhGH treatment was assessed by the use of linear mixed-effects models.

RESULTS

Patients in the rhGH group spent longer time on dialysis and less frequently underwent living related KT compared to the non-prior rhGH group but showed similar height z-scores at the time of KT. After KT, steroid exposure was lower and increments in anthropometric z-scores were significantly higher in the rhGH group compared to those in the non-prior rhGH group, although 18% of patients in the latter group were started on rhGH after KT. Non-prior rhGH treatment was associated with a faster decline in transplant function, lower hemoglobin, and higher C-reactive protein levels (CRP). After adjustment for these confounders, growth outcome did statistically differ for sitting height z-scores only.

CONCLUSIONS

Treatment with rhGH prior to KT was associated with superior growth outcome in prepubertal kidney transplant recipients, which was related to better transplant function, lower CRP, less anemia, lower steroid exposure, and earlier maturation after KT. A higher resolution version of the Graphical abstract is available as Supplementary information.

Nutritional Assessment and Management in Paediatric Chronic Kidney Disease

Nutrition in paediatrics has always been one of the most important factors for optimal growth. Children with chronic kidney disease (CKD) need special consideration for better long-term outcomes, including nutritional status, optimal height, and cognitive function. Nonetheless, there are many obstacles to overcome to attain optimal linear growth and nutritional status in children with CKD. This review highlights the need for tools to assess the growth parameters in CKD. In addition, recommendations for dietary intake play a major role in controlling electrolyte disturbances in patients with CKD. For example, it is still unclear whether it is better to restrict phosphate sources in inorganic, organic, or food additives. The review also summarises different factors such as fluid intake, route of feeding, and essential nutrients that require particular attention in paediatric patients with CKD. In summary, a multidisciplinary team is needed to devise individual nutritional plans to achieve the best outcome and improve the quality of life of patients.

Incidence of and risk factors for short stature in children with chronic kidney disease: results from the KNOW-Ped CKD

BACKGROUND

Preserving optimal growth has long been a significant concern for children with chronic kidney disease (CKD). We aimed to examine the incidence of and risk factors for short stature in Asian pediatric patients with CKD.

METHODS

We analyzed growth status by height, weight, and body mass index (BMI) standard deviation scores (SDSs) for 432 participants in the KoreaN cohort study for Outcome in patients With Pediatric Chronic Kidney Disease.

RESULTS

The median height, weight, and BMI SDSs were - 0.94 (interquartile range (IQR) - 1.95 to 0.05), - 0.58 (IQR - 1.46 to 0.48), and - 0.26 (IQR - 1.13 to 0.61), respectively. A high prevalence of short stature (101 of 432 patients, 23.4%) and underweight (61 of 432 patients, 14.1%) was observed. In multivariable logistic regression analysis, CKD stages 4 and 5 (adjusted odds ratio (aOR) 2.700, p = 0.001), onset before age 2 (aOR 2.928, p < 0.0001), underweight (aOR 2.353, p = 0.013), premature birth (aOR 3.484, p < 0.0001), LBW (aOR 3.496, p = 0.001), and low household income (aOR 1.935, p = 0.030) were independent risk factors associated with short stature in children with CKD.

CONCLUSIONS

Children with CKD in Korea were shorter and had lower body weight and BMI than the general population. Short stature in children with CKD was most independently associated with low birth weight, followed by premature birth, onset before age 2, CKD stages 4 and 5, underweight, and low household income. Among these, underweight is the only modifiable factor. Therefore, we suggest children with CKD should be carefully monitored for weight, nutritional status, and body composition to achieve optimal growth.

Growth in children on kidney replacement therapy: a review of data from patient registries

Growth retardation is a major complication in children with chronic kidney disease (CKD) and on kidney replacement therapy (KRT). Conversely, better growth in childhood CKD is associated with an improvement in several hard morbidity-mortality endpoints. Data from pediatric international registries has demonstrated that improvements in the overall conservative management of CKD, the search for optimal dialysis, and advances in immunosuppression and kidney transplant techniques have led to a significant improvement of final height over time. Infancy still remains a critical period for adequate linear growth, and the loss of stature during the first years of life influences final height. Preliminary new original data from the European Society for Paediatric Nephrology/European Renal Association-European Dialysis and Transplant Association (ESPN/ERA-EDTA) Registry confirm an association between the final height and the height attained at 2 years in children on KRT.

Bone Disease in CKD in Children

This manuscript discusses mineral and bone disorders of chronic kidney disease (MBD-CKD) in pediatric patients with special emphasis on the underlying pathophysiology, the causes and clinical profile of growth retardation, the alterations in the growth plate, the strategies to optimize growth and the medical recommendations for prevention and treatment.

The Role of Growth Hormone in Chronic Kidney Disease

Growth hormone (GH) has become a critical therapy for treating growth delay and failure in pediatric chronic kidney disease. Recombinant human GH treatment is safe and significantly improves height and height velocity in these growing patients and improved growth outcomes are associated with decreased morbidity and mortality as well as improved quality of life. However, the utility of recombinant human GH in adults with chronic kidney disease and end-stage renal disease for optimization of body habitus and reducing frailty remains uncertain. Semin Nephrol 41:x-xx © 2021 Elsevier Inc. All rights reserved.

Determinants of growth after kidney transplantation in prepubertal children

BACKGROUND

Short stature is a frequent complication after pediatric kidney transplantation (KT). Whether the type of transplantation and prior treatment with recombinant human growth hormone (GH) affects post-transplant growth, is unclear.

METHODS

Body height, leg length, sitting height, and sitting height index (as a measure of body proportions) were prospectively investigated in 148 prepubertal patients enrolled in the CKD Growth and Development study with a median follow-up of 5.0 years. We used linear mixed-effects models to identify predictors for body dimensions.

RESULTS

Pre-transplant Z scores for height (- 2.18), sitting height (- 1.37), and leg length (- 2.30) were reduced, and sitting height index (1.59) was increased compared to healthy children, indicating disproportionate short stature. Catch-up growth in children aged less than 4 years was mainly due to stimulated trunk length, and in older children to improved leg length, resulting in normalization of body height and proportions before puberty in the majority of patients. Use of GH in the pre-transplant period, congenital CKD, birth parameters, parental height, time after KT, steroid exposure, and transplant function were significantly associated with growth outcome. Although, unadjusted growth data suggested superior post-transplant growth after (pre-emptive) living donor KT, this was no longer true after adjusting for the abovementioned confounders.

CONCLUSIONS

Catch-up growth after KT is mainly due to stimulated trunk growth in young children (< 4 years) and improved leg growth in older children. Beside transplant function, steroid exposure and use of GH in the pre-transplant period are the main potentially modifiable factors associated with better growth outcome.

Growth Patterns After Kidney Transplantation in European Children Over the Past 25 Years: An ESPN/ERA-EDTA Registry Study

BACKGROUND

Improved management of growth impairment might have resulted in less growth retardation after pediatric kidney transplantation (KT) over time. We aimed to analyze recent longitudinal growth data after KT in comparison to previous eras, its determinants, and the association with transplant outcome in a large cohort of transplanted children using data from the European Society for Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry.

METHODS

A total of 3492 patients transplanted before 18 years from 1990 to 2012 were included. Height SD scores (SDS) were calculated using recent national or European growth charts. We used generalized equation models to estimate the prevalence of growth deficit and linear mixed models to calculate adjusted mean height SDS.

RESULTS

Mean adjusted height post-KT was -1.77 SDS. Height SDS was within normal range in 55%, whereas 28% showed moderate, and 17% severe growth deficit. Girls were significantly shorter than boys, but catch-up growth by 5 years post-KT was observed in both boys and girls. Children <6 years were shortest at KT and showed the greatest increase in height, whereas there was no catch-up growth in children transplanted >12.

CONCLUSIONS

Catch-up growth post-KT remains limited, height SDS did not improve over time, resulting in short stature in nearly half of transplanted children in Europe.

Summary of Expert Opinion on the Management of Children With Chronic Kidney Disease and Growth Failure With Human Growth Hormone

Background: The management of children and adolescents with chronic kidney disease (CKD) and growth failure candidate for recombinant human growth hormone therapy (rhGH) is based on an appraisal of the literature established on a 2006 consensus statement and 2019 Clinical practice recommendations. The performance of these guidelines has never been tested. Aims: The objective of this study was to establish the level of adherence to international guidelines based on the 2006 consensus and the 2019 criteria that lead to the initiation of growth hormone treatment by both pediatric endocrinologists and pediatric nephrologists. Methods: A multidisciplinary team of pediatric endocrinologists and pediatric nephrologists, members of the Italian Society of Pediatric Endocrinology or of the Italian Society of Pediatric Nephrology, discussed and reviewed the main issues related to the management of pediatric patients with CKD who need treatment with rhGH. Experts developed 11 questions focusing on risk assessment and decision makings in October 2019 and a survey was sent to forty pediatric endocrinologists (n = 20) and nephrologists (n = 20) covering the whole national territory. The results were then analyzed and discussed in light of current clinical practice guidelines and recent recommendations. Results: Responses were received from 32 of the 40 invited specialists, 17 of whom were pediatric endocrinologists (42.5%) and 15 pediatric nephrologists (37.5%). Although all the centers that participated in the survey agreed to follow the clinical and biochemical diagnostic work-up and the criteria for the treatment of patients with CKD, among the Italian centers there was a wide variety of decision-making processes. Conclusions: Despite current guidelines for the management of children with CKD and growth failure, its use varies widely between centers and rhGH is prescribed in a relatively small number of patients and rarely after kidney transplantation. Several raised issues are not taken into account by international guidelines and a multidisciplinary approach with mutual collaboration between specialists will improve patient care based on their unmet needs.

Innovative Three-Dimensional Microscopic Analysis of Uremic Growth Plate Discloses Alterations in the Process of Chondrocyte Hypertrophy: Effects of Growth Hormone Treatment

Chronic kidney disease (CKD) alters the morphology and function of the growth plate (GP) of long bones by disturbing chondrocyte maturation. GP chondrocytes were analyzed in growth-retarded young rats with CKD induced by adenine intake (AD), control rats fed ad libitum (C) or pair-fed with the AD group (PF), and CKD rats treated with growth hormone (ADGH). In order to study the alterations in the process of GP maturation, we applied a procedure recently described by our group to obtain high-quality three-dimensional images of whole chondrocytes that can be used to analyze quantitative parameters like cytoplasm density, cell volume, and shape. The final chondrocyte volume was found to be decreased in AD rats, but GH treatment was able to normalize it. The pattern of variation in the cell cytoplasm density suggests that uremia could be causing a delay to the beginning of the chondrocyte hypertrophy process. Growth hormone treatment appears to be able to compensate for this disturbance by triggering an early chondrocyte enlargement that may be mediated by Nkcc1 action, an important membrane cotransporter in the GP chondrocyte enlargement.

Growth characterization in a cohort of renal allograft recipients

INTRODUCTION

Growth retardation is a common problem in children with CKD. This study aims to describe growth, prevalence of short stature before RTx, catch-up growth after RTx, and associated factors.

METHODS

We retrospectively reviewed 74 renal allograft recipients who underwent RTx at Fundación Cardioinfantil, Colombia, between January 2008 and September 2016 with follow-up for 2 years afterwards. Pre-RTx Height_SDS and demographic characteristics were compared between children with normal and short stature. Post-RTx Height_SDS at 1 and 2 years post-RTx and FAH, when available, were retrieved. Children were classified into catch-up growth and no catch-up growth groups depending on whether or not Height_SDS increased ≥0.5 per year within the first 2 years post-RTx. Possible associated factors were compared.

RESULTS

Seventy-four patients were included. Mean age at RTx was 11 ± 4.0 years, and 43.2% (32/74) were females. Mean Height_SDS for the entire study population at pre-RTx was -2.8 ± 1.5. Before RTx, 68.9% (51/74) had short stature, and 44.6% (33/74) had severe short stature. 37.2% presented catch-up growth post-RTx. Time on dialysis was associated with short pre-RTx stature (OR 1.66; 95% CI [1.15-2.39]; P = .006) and catch-up growth (OR 2.15; 95% CI [1.15-3.99]; P = .016). 44.59% (33/74) reached FAH, and 48.4% (16/33) presented short FAH.

CONCLUSIONS

Growth continues to be suboptimal after RTx. Given that pre-RTx height is a significantly associated factor, it is important to plan early interventions in terms of growth improvement in these children.

Growth plate alterations in chronic kidney disease

Growth retardation is a major feature of chronic kidney disease (CKD) of onset in infants or children and is associated with increased morbidity and mortality. Several factors have been shown to play a causal role in the growth impairment of CKD. All these factors interfere with growth by disturbing the normal physiology of the growth plate of long bones. To facilitate the understanding of the pathogenesis of growth impairment in CKD, this review discusses cellular and molecular alterations of the growth plate during uremia, including structural and dynamic changes of chondrocytes, alterations in their process of maturation and hypertrophy, and disturbances in the growth hormone signaling pathway.

Sex and age as determinants for high blood pressure in pediatric renal transplant recipients: a longitudinal analysis of the CERTAIN Registry

BACKGROUND

High prevalence of arterial hypertension is known in pediatric renal transplant patients, but how blood pressure (BP) distribution and control differ between age groups and whether sex and age interact and potentially impact BP after transplantation have not been investigated.

METHODS

This retrospective analysis included 336 pediatric renal transplant recipients (62% males) from the Cooperative European Pediatric Renal Transplant Initiative Registry (CERTAIN) with complete BP measurement at discharge and 1, 2 and 3 years post-transplant.

RESULTS

At discharge and 3 years post-transplant, arterial hypertension was highly prevalent (84% and 77%); antihypertensive drugs were used in 73% and 68% of the patients. 27% suffered from uncontrolled and 9% from untreated hypertension at 3 years post-transplant. Children transplanted at age < 5 years showed sustained high systolic BP z-score and received consistently less antihypertensive treatment over time. Younger age, shorter time since transplantation, male sex, higher body mass index (BMI), high cyclosporine A (CSA) trough levels, and a primary renal disease other than congenital anomalies of the kidney and urinary tract (CAKUT) were significantly associated with higher systolic BP z-score. Sex-stratified analysis revealed a significant association between high CSA and higher systolic BP in older girls that likely had started puberty already. An association between BP and estimated glomerular filtration rate was not detected.

CONCLUSIONS

BP control during the first 3 years was poor in this large European cohort. The description of age- and sex-specific risk profiles identified certain recipient groups that may benefit from more frequent BP monitoring (i.e. young children) or different choices of immunosuppression (i.e. older girls).

Strategies for Optimizing Growth in Children With Chronic Kidney Disease

Growth failure is a hallmark in children with chronic kidney disease (CKD). Therefore, early diagnosis and adequate management of growth failure is of utmost importance in these patients. The risk of severe growth retardation is the higher the younger the child is, which places an additional burden on patients and their families and hampers the psychosocial integration of these children. Careful monitoring of growth, and effective interventions are mandatory to prevent and treat growth failure in children with CKD at all ages and all stages of kidney failure. Early intervention is critical, as all therapeutic interventions are much more effective if they are started prior to the initiation of dialysis. Prevention and treatment of growth failure focuses on: (i) preservation of renal function, e.g., normalization of blood pressure and proteinuria by use of inhibitors of the renin-angiotensin aldosterone system, (ii) adequate energy intake, including tube feeding or gastrostomy in case of persisting malnutrition, (iii) substitution of water and electrolytes, especially in children with renal malformation, (iv) correction of metabolic acidosis, (v) control of parathyroid hormone levels within the CKD-dependent target range, (vi) use of recombinant human growth hormone in cases of persistent growth failure, and, (vii) early/preemptive kidney transplantation using steroid-minimizing immunosuppressive protocols in children with end-stage CKD. This review discusses these measures based on recent guidelines.

Human Papillomavirus Vaccination in Male and Female Adolescents Before and After Kidney Transplantation: A Pediatric Nephrology Research Consortium Study

Background: Kidney transplant (KT) recipients have higher incidence of malignancies, including Human Papillomavirus (HPV)-associated cancers. Thus, HPV vaccines may have an important role in preventing HPV-related disease in this population; however, immunogenicity and safety data are lacking. Objective: To examine the immunological response and tolerability to HPV vaccination in pediatric KT recipients compared to future KT candidates. Methods: The quadrivalent HPV vaccine was administered to girls and boys age 9-18 recruited from seven centers part of the Pediatric Nephrology Research Consortium. Subjects were recruited for three groups: (1) CKD: chronic kidney disease stages 3, 4, and 5 not on dialysis; (2) Dialysis; (3) KT recipients. The outcome consisted of antibody concentrations against HPV 6, 11, 16, and 18. Geometric mean titers (GMTs) and seroconversion rates were compared. Vaccine tolerability was assessed. Results: Sixty-five participants were recruited: 18 in the CKD, 18 in the dialysis, and 29 into the KT groups. KT patients had significantly lower GMTs after vaccination for all serotypes. The percentages of subjects who reached seroconversion were overall lower for the KT group, reaching statistical significance for HPV 6, 11, and 18. Comparing immunosuppressed subjects (anyone taking immunosuppression medications, whether KT recipient or not) with the non-immunosuppressed participants, the former had significantly lower GMTs for all the HPV serotypes and lower seroconversion rates for HPV 6, 11, and 18. KT females had higher GMTs and seroconversion rates for certain serotypes. There were no adverse events in either group. Conclusions: HPV vaccine was well-tolerated in this population. Pediatric KT recipients had in general lower GMTs and seroconversion rates compared to their peers with CKD or on dialysis. Immunosuppression played a role in the lack of seroconversion. Our results emphasize the importance of advocating for HPV vaccination prior to KT and acknowledge its safety post transplantation. Future studies are needed to investigate the effect of a supplemental dose of HPV vaccine in KT recipients who do not seroconvert and to evaluate the long-term persistence of antibodies post-KT.

Early puberty in end stage renal failure and renal transplant recipients

Background Delayed puberty and hypogonadism are common in children with chronic kidney disease and in renal transplant recipients, but precocious puberty has rarely been reported in these populations. We describe six girls with precocious and/or early-onset, rapidly progressive puberty before and following renal transplantation. Methods Of 112 children under the age of 18 years (67 boys, 45 girls) who received renal transplants between 2010 and 2018, six girls presented with precocious or rapidly progressive early puberty at ages 6-7/12, 7-2/12, 7-4/12, 8, 8-8/12 and 8-11/12 years. Clinical evaluation included measurements of height, weight, body mass index (BMI), Tanner staging and bone age assessment. Gonadotropin responses to intravenous gonadotropin releasing hormone (GnRH) or intramuscular triptorelin acetate were determined. Results Tanner breast stage 3 was noted at 2-6 years following renal transplantation in five girls, four with preserved kidney function. One girl began puberty before renal transplantation. Peak luteinizing hormone (LH) and follicular stimulating hormone (FSH) levels were 6.5, 20.2, 7.83, 19.1, 9 and 2.2 mIU/mL and 13, 8.3, 8.01, 7.5, 8.1 and 7.7 mIU/mL, respectively. Treatment with an intramuscular slow-release formulation of triptorelin acetate every 4 weeks slowed progression of breast development. Conclusions Although delayed puberty is more common in children with renal disease, precocious puberty can also be seen. Evaluation of growth and puberty by a pediatric endocrinologist should be part of the routine care for all children following kidney transplantation.

Clinical practice recommendations for growth hormone treatment in children with chronic kidney disease

Achieving normal growth is one of the most challenging problems in the management of children with chronic kidney disease (CKD). Treatment with recombinant human growth hormone (GH) promotes longitudinal growth and likely enables children with CKD and short stature to reach normal adult height. Here, members of the European Society for Paediatric Nephrology (ESPN) CKD–Mineral and Bone Disorder (MBD), Dialysis and Transplantation working groups present clinical practice recommendations for the use of GH in children with CKD on dialysis and after renal transplantation. These recommendations have been developed with input from an external advisory group of paediatric endocrinologists, paediatric nephrologists and patient representatives. We recommend that children with stage 3–5 CKD or on dialysis should be candidates for GH therapy if they have persistent growth failure, defined as a height below the third percentile for age and sex and a height velocity below the twenty-fifth percentile, once other potentially treatable risk factors for growth failure have been adequately addressed and provided the child has growth potential. In children who have received a kidney transplant and fulfil the above growth criteria, we recommend initiation of GH therapy 1 year after transplantation if spontaneous catch-up growth does not occur and steroid-free immunosuppression is not a feasible option. GH should be given at dosages of 0.045–0.05 mg/kg per day by daily subcutaneous injections until the patient has reached their final height or until renal transplantation. In addition to providing treatment recommendations, a cost-effectiveness analysis is provided that might help guide decision-making.

This Evidence-Based Guideline developed by members of the European Society for Paediatric Nephrology CKD-MBD, Dialysis and Transplantation working groups presents clinical practice recommendations for the use of growth hormone in children with chronic kidney disease on dialysis and after renal transplantation.

Pediatric bone evaluation with HR-pQCT: A comparison between standard and height-adjusted positioning protocols in a cohort of teenagers with chronic kidney disease

BACKGROUND

High-resolution peripheral quantitative computed tomography (HR-pQCT) evaluates different components of bone fragility. The positioning and length of the region of interest (ROI) in growing populations remain to be defined.

METHODS

Using HR-pQCT at the ultradistal tibia, we compared a single-center cohort of 28 teenagers with chronic kidney disease (CKD) at a median age of 13.6 (range, 10.2-19.9) years to local age-, gender-, and puberty-matched healthy peers. Because of the potential impact of short stature, bone parameters were assessed on two different leg-length-adjusted ROIs in comparison to the standard analysis, namely the one applied in adults. The results are presented as median (range).

RESULTS

After matching, SDS height was -0.9 (-3.3;1.6) and 0.3 (-1.4;2.0) in patients and controls, respectively (P<0.001). In younger children (e.g., prepubertal, n=11), bone texture parameters and bone strength were not different using standard analysis. However, using a height-adjusted ROI enabled better characterization of cortical bone structure. In older patients (e.g., pubertal, n=17), there were no differences for height between patients and controls: with the standard evaluation, cortical bone area and cortical thickness were significantly lower in CKD patients: 85 (50-124) vs. 108 (67-154) mm² and 0.89 (0.46-1.31) vs 1.09 (0.60-1.62) mm, respectively (both P<0.05).

CONCLUSIONS

Adapting the ROI to leg length enables better assessment of bone structure, especially when height discrepancies exist between controls and patients. Larger cohorts are required to prospectively validate this analytic HR-pQCT technique.

Growth and Nutrition in Pediatric Chronic Kidney Disease

Children with chronic kidney disease (CKD) feature significant challenges to the maintenance of adequate nutrition and linear growth. Moreover, the impaired nutritional state contributes directly to poor growth. Therefore, it is necessary to consider nutritional status in the assessment of etiology and treatment of sub-optimal linear growth. The major causes of poor linear growth including dysregulation of the growth hormone/insulin-like growth factor-I (IGF-I) axis, nutritional deficiency, metabolic acidosis, anemia, renal osteodystrophy/bone mineral disease, and inflammation. This review summarizes the causes and assessment tools of growth and nutrition while providing a summary of state of the art therapies for these co-morbidities of pediatric CKD.

Pubertal development in children with chronic kidney disease

Impairment of pubertal growth and sexual maturation resulting in reduced adult height is an significant complication in children suffering from chronic kidney disease (CKD). Delayed puberty and reduced pubertal growth are most pronounced in children with pre-existing severe stunting before puberty, requiring long-term dialysis treatment, and in transplanted children with poor graft function and high glucocorticoid exposure. In pre-dialysis patients, therapeutic measures to improve pubertal growth are limited and mainly based on the preservation of renal function and the use of growth hormone treatment. In patients with end-stage CKD, early kidney transplantation with steroid withdrawal within 6 months of renal transplantation allows for normal pubertal development in the majority of patients. This review focuses on the underlying pathophysiology and strategies for improving height and development in these patients.

Kidney transplantation fails to provide adequate growth in children with chronic kidney disease born small for gestational age

BACKGROUND

Children with chronic kidney disease are frequently born small for gestational age (SGA) and prone to disproportionately short stature. It is unclear how SGA affects growth after kidney transplantation (KTx).

METHODS

Linear growth (height, sitting height, and leg length) was prospectively investigated in a cohort of 322 pediatric KTx recipients, with a mean follow-up of 4.9 years. Sitting height index (ratio of sitting height to total body height) was used to assess body proportions. Predictors of growth outcome in KTx patients with (n = 94) and without (n = 228) an SGA history were evaluated by the use of linear mixed-effects models.

RESULTS

Mean z-scores for all linear body dimensions were lower in SGA compared with non-SGA patients (p < 0.001). SGA patients presented with higher target height deficit and degree of body disproportion (p < 0.001). The latter was mainly due to reduced leg growth during childhood. Pubertal trunk growth was diminished in SGA patients, and the pubertal growth spurt of legs was delayed in both groups, resulting in further impairment of adult height, which was more frequently reduced in SGA than in non-SGA patients (50 % vs 18 %, p < 0.001). Use of growth hormone treatment in the pre-transplant period, preemptive KTx, transplant function, and control of metabolic acidosis were the only potentially modifiable correlates of post-transplant growth in SGA groups. By contrast, living related KTx, steroid exposure, and degree of anemia proved to be correlates in non-SGA only.

CONCLUSIONS

In children born SGA, growth outcome after KTx is significantly more impaired and affected by different clinical parameters compared with non-SGA patients.

Growth hormone therapy in children with CKD after more than two decades of practice

This review focuses on the evidence for the efficacy and safety of recombinant human growth hormone (rhGH) therapy in children with all stages of chronic kidney disease (CKD) and at all ages. It describes the improving height prognosis for our patients both with and without rhGH; explains the underlying hormonal abnormalities that provide the rationale for rhGH use in CKD and the endocrine changes that accompany treatment; and views on who warrants treatment, with what dose, and how long for.

Growth and nutritional status in children with chronic kidney disease on maintenance dialysis in Poland

PURPOSE

Despite vast availability of modern methods of treatment of chronic kidney disease and its complications, the short stature still is a major point of concern in adolescents with chronic kidney disease. The aim of the study was to assess changes in growth and nutritional status of Polish children on renal replacement therapy in the decade, 2004-2013.

MATERIAL AND METHODS

The study was designed as a cross-sectional analysis of anthropometric values and selected indices of growth status amongst children receiving dialysis in Poland between the years 2004 and 2013. Data were acquired during two different multicentre studies on hypertension in dialyzed children in Poland. Basic anthropometric parameters (body weight, body height/length, body mass index - BMI), dialysis adequacy and duration of RRT were assessed.

RESULTS

The study showed that anthropometric parameters of children undergoing renal replacement therapy had not significantly changed in the last 10 years of observation. Children on RRT were still of short stature despite availability of modern methods of hormonal therapy and nutrition. Median of height z-score was -2.10 in 2004 and -2.19 in 2013. Expected clinical improvement in these measures was not proven.

CONCLUSIONS

The cause of chronic kidney disease, method of dialysis, time on dialysis or dialysis adequacy did not influence the anthropometric parameters significantly in dialyzed children in Poland.

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.

Patterns of growth after kidney transplantation among children with ESRD

BACKGROUND AND OBJECTIVES

Poor linear growth is a frequent complication of CKD. This study evaluated the effect of kidney transplantation on age-related growth of linear body segments in pediatric renal transplant recipients who were enrolled from May 1998 until August 2013 in the CKD Growth and Development observational cohort study.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Linear growth (height, sitting height, arm and leg lengths) was prospectively investigated during 1639 annual visits in a cohort of 389 pediatric renal transplant recipients ages 2-18 years with a median follow-up of 3.4 years (interquartile range, 1.9-5.9 years). Linear mixed-effects models were used to assess age-related changes and predictors of linear body segments.

RESULTS

During early childhood, patients showed lower mean SD scores (SDS) for height (-1.7) and a markedly elevated sitting height index (ratio of sitting height to total body height) compared with healthy children (1.6 SDS), indicating disproportionate stunting (each P<0.001). After early childhood a sustained increase in standardized leg length and a constant decrease in standardized sitting height were noted (each P<0.001), resulting in significant catch-up growth and almost complete normalization of sitting height index by adult age (0.4 SDS; P<0.01 versus age 2-4 years). Time after transplantation, congenital renal disease, bone maturation, steroid exposure, degree of metabolic acidosis and anemia, intrauterine growth restriction, and parental height were significant predictors of linear body dimensions and body proportions (each P<0.05).

CONCLUSIONS

Children with ESRD present with disproportionate stunting. In pediatric renal transplant recipients, a sustained increase in standardized leg length and total body height is observed from preschool until adult age, resulting in restoration of body proportions in most patients. Reduction of steroid exposure and optimal metabolic control before and after transplantation are promising measures to further improve growth outcome.

Medication adherence and growth in children with CKD

BACKGROUND AND OBJECTIVES

Poor growth is a consequence of CKD, but can often be partially or fully prevented or corrected with the use of a number of medications. The extent of nonadherence with medications used to treat or mitigate growth failure in CKD has not been examined prospectively in children with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The prevalence of both prescription of and nonadherence to recombinant human growth hormone (rhGH), phosphate binders, alkali, active vitamin D, nutritional vitamin D, iron, and erythrocyte-stimulating agents was summarized over the first seven visits of the Chronic Kidney Disease in Children cohort study. The association between self-reported nonadherence to each medication group and the mean annual change in age- and sex-specific height z score was quantified using seven separate linear regression models with generalized estimating equations.

RESULTS

Of 834 participants, 597 reported use of at least one of these medication groups and had adherence data available. Nonadherence ranged from 4% over all visits for erythrocyte-stimulating agents to 22% over all visits for nutritional vitamin D. Of the study participants, 451 contributed data to at least one of the analyses of adherence and changes in height z score. Children nonadherent to rhGH had no change in height z score, whereas those adherent to rhGH had a significant improvement of 0.16 SDs (95% confidence interval, 0.05 to 0.27); the effect size was slightly larger and remained significant after adjustment. Among participants with height≤3rd percentile and after adjustment, adherence to rhGH was associated with a 0.33 SD (95% confidence interval, 0.10 to 0.56) greater change in height z score. Nonadherence with other medication groups was not significantly associated with a change in height z score.

CONCLUSIONS

Self-reported nonadherence to rhGH was associated with poorer growth velocity in children with CKD, suggesting an opportunity for intervention and improved patient outcome.

Reduced ATG-F dosage for induction in pediatric renal transplantation: a single-center experience

Rabbit antithymocyte globulin (ATG-F) is an extensively used induction agent. To our knowledge, no study to date has assessed reduced ATG-F dosage in children undergoing renal transplantation. This was a retrospective analysis of pediatric renal recipients in the Department of Kidney Transplantation, The First Affiliated Hospital of Zhengzhou University, from May 2007 to February 2013. Thirty-nine children underwent renal transplantation including 25 living related and 14 cardiac deceased donor transplantation. Each recipient received ATG-F 1.5 mg/kg/d once daily for 4 days. Of the 39 recipients, five (12.8%) showed delayed graft function, including one of 25 recipients (4%) of living donor and four of 14 recipients (28.6%) of deceased donor transplantation (p < 0.05). Six of the 39 recipients (15.4%) showed acute rejection on renal biopsy. Follow-up in these children ranged from 6 to 87 months. The one-, three-, and five-yr recipients and grafts survival rates postoperation were each 94.9% and 97.3%, 97.3%, and 94.6%, respectively. The incidence of postoperative infection was 35.9% (14/39), and did not differ significantly in the living related and deceased donor groups (p > 0.05). Low-dose ATG-F can be safely used as an immune induction agent in pediatric renal transplantation.

Growth in children on renal replacement therapy: a shrinking problem?

Growth failure has been almost inextricably linked with chronic kidney disease (CKD) and end-stage renal disease (ESRD) since initial reports of renal dwarfism dating back to the turn of the twentieth century. Growth failure in CKD has been associated with both increased morbidity and mortality. Growth failure in the setting of kidney disease is multifactorial and is related to poor nutritional status as well as comorbidities, such as anemia, bone and mineral disorders, and alterations in hormonal responses, as well as to aspects of treatment such as steroid exposure. In this issue of Pediatric Nephrology, Franke et al. report on the gains made in growth and maturation in pediatric patients with ESRD in recent decades, particularly in Germany. Through advances in the care of CKD and ESRD over recent decades, the prevalence of growth failure appears to be decreasing. These findings, along with a recent report demonstrating decreases in mortality in childhood ESRD in the United States Renal Data System (USRDS), suggest overall improvements in the outcomes of care, perhaps reflecting improvements in the quality of care for children with kidney disease worldwide.