Choosing fluids to reduce the risks of acute electrolyte disturbances in children after a kidney transplant

Intravenous (i.v.) fluid therapy is critically important in pediatric kidney transplantation. Because of the high volumes given perioperatively, transplant recipients can develop significant electrolyte abnormalities depending on the types of fluids used. Current practices in pediatric transplantation aim to balance risks of hyponatremia from traditionally used hypotonic fluids, such as 0.45% sodium chloride, against hyperchloremia and acidosis associated with isotonic 0.9% sodium chloride. Using the balanced solution Plasma-Lyte 148 as an alternative might mitigate these risks.

Balanced crystalloid solution versus saline in deceased donor kidney transplantation (BEST-Fluids): a pragmatic, double-blind, randomised, controlled trial

BACKGROUND

Delayed graft function (DGF) is a major adverse complication of deceased donor kidney transplantation. Intravenous fluids are routinely given to patients receiving a transplant to maintain intravascular volume and optimise graft function. Saline (0·9% sodium chloride) is widely used but might increase the risk of DGF due to its high chloride content. We aimed to test our hypothesis that using a balanced low-chloride crystalloid solution (Plasma-Lyte 148) instead of saline would reduce the incidence of DGF.

METHODS

BEST-Fluids was a pragmatic, registry-embedded, multicentre, double-blind, randomised, controlled trial at 16 hospitals in Australia and New Zealand. Adults and children of any age receiving a deceased donor kidney transplant were eligible; those receiving a multi-organ transplant or weighing less than 20 kg were excluded. Participants were randomly assigned (1:1) using an adaptive minimisation algorithm to intravenous balanced crystalloid solution (Plasma-Lyte 148) or saline during surgery and up until 48 h after transplantation. Trial fluids were supplied in identical bags and clinicians determined the fluid volume, rate, and time of discontinuation. The primary outcome was DGF, defined as receiving dialysis within 7 days after transplantation. All participants who consented and received a transplant were included in the intention-to-treat analysis of the primary outcome. Safety was analysed in all randomly assigned eligible participants who commenced surgery and received trial fluids, whether or not they received a transplant. This study is registered with Australian New Zealand Clinical Trials Registry, (ACTRN12617000358347), and ClinicalTrials.gov (NCT03829488).

FINDINGS

Between Jan 26, 2018, and Aug 10, 2020, 808 participants were randomly assigned to balanced crystalloid (n=404) or saline (n=404) and received a transplant (512 [63%] were male and 296 [37%] were female). One participant in the saline group withdrew before 7 days and was excluded, leaving 404 participants in the balanced crystalloid group and 403 in the saline group that were included in the primary analysis. DGF occurred in 121 (30%) of 404 participants in the balanced crystalloid group versus 160 (40%) of 403 in the saline group (adjusted relative risk 0·74 [95% CI 0·66 to 0·84; p<0·0001]; adjusted risk difference 10·1% [95% CI 3·5 to 16·6]). In the safety analysis, numbers of investigator-reported serious adverse events were similar in both groups, being reported in three (<1%) of 406 participants in the balanced crystalloid group versus five (1%) of 409 participants in the saline group (adjusted risk difference -0·5%, 95% CI -1·8 to 0·9; p=0·48).

INTERPRETATION

Among patients receiving a deceased donor kidney transplant, intravenous fluid therapy with balanced crystalloid solution reduced the incidence of DGF compared with saline. Balanced crystalloid solution should be the standard-of-care intravenous fluid used in deceased donor kidney transplantation.

FUNDING

Medical Research Future Fund and National Health and Medical Research Council (Australia), Health Research Council (New Zealand), Royal Australasian College of Physicians, and Baxter.

The impact of donor/recipient age difference and HLA mismatch on graft outcome in pediatric kidney transplantation

BACKGROUND

Understanding the relationship between the factors that influence long-term kidney transplant survival remains a key priority for pediatric nephrologists. We assessed the relative impact of donor/recipient age difference and HLA matching on long-term graft outcomes.

METHODS

We conducted a retrospective cohort study of pediatric and adolescent recipients who received a primary kidney transplant in Australia and New Zealand between January 1, 1990, and December 31, 2015. The primary outcome was graft survival analyzed by Kaplan-Meier method.

RESULTS

During the 26-year period, 1134 primary (395 DD and 739 LD) kidney transplants were performed in recipients less than 20 years of age. The median follow-up time was 10.2 years. Overall, 405 patients (35.7%) lost their transplant with graft survival 93.8% at 1 year, 82.5% at 5 years, 65.8% at 10 years, and 49.9% at 15 years post-transplant. There was consistently higher graft loss of DD kidneys as compared to LD kidneys at each time point. Both increasing donor/recipient age difference (aHR 1.11 per 10 years; 95% CI, 1.02-1.20; P = 0.009) and increasing HLA mismatch (aHR 1.20 per mismatch; 95% CI, 1.10-1.30; P < 0.001) were associated with decreased graft survival.

CONCLUSIONS

Donor/recipient age difference and HLA matching are important factors influencing long-term graft outcomes in pediatric kidney transplantation. HLA mismatch remains a strong predictor of graft loss. For patients without the option of a LD, we suggest that the degree of HLA mismatch should not be discounted as part of the decision-making process of organ allocation.

Socio-economic status and quality of life in children with chronic disease: A systematic review

Reduced quality of life (QoL) is a known consequence of chronic disease in children, and this association may be more evident in those who are socio-economically disadvantaged. The aims of this systematic review were to assess the association between socio-economic disadvantage and QoL among children with chronic disease, and to identify the specific socio-economic factors that are most influential. MEDLINE, Embase and PsycINFO were searched to March 2015. Observational studies that reported the association between at least one measure of social disadvantage in caregivers and at least one QoL measure in children and young people (age 2-21 years) with a debilitating non-communicable childhood disease (asthma, chronic kidney disease, type 1 diabetes mellitus and epilepsy) were eligible. A total of 30 studies involving 6957 patients were included (asthma (six studies, n = 576), chronic kidney disease (four studies, n = 796), epilepsy (14 studies, n = 2121), type 1 diabetes mellitus (six studies, n = 3464)). A total of 22 (73%) studies reported a statistically significant association between at least one socio-economic determinant and QoL. Parental education, occupation, marital status, income and health insurance coverage were associated with reduced QoL in children with chronic disease. The quality of the included studies varied widely and there was a high risk of reporting bias. Children with chronic disease from lower socio-economic backgrounds experience reduced QoL compared with their wealthier counterparts. Initiatives to improve access to and usage of medical and psychological services by children and their families who are socio-economically disadvantaged may help to mitigate the disparities and improve outcomes in children with chronic illnesses.

Long-Term Outcome of Kidney Transplantation in Recipients with Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES

FSGS can recur after kidney transplantation and is associated with poor graft outcomes. We aimed to assess the incidence of FSGS recurrence post-transplant and determine the effect of graft source on recurrence and graft survival in patients with biopsy-proven FSGS.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using the Australian and New Zealand Dialysis and Transplant Registry, we assessed incidence of FSGS, the influence of donor type on the risk of FSGS recurrence, and graft loss in recipients with ESRD caused by primary FSGS using Kaplan-Meier and logistic regression analyses.

RESULTS

Between 1992 and 2011, 736 first kidney transplants were performed in 666 adults and 70 children (≤20 years old) with biopsy-proven primary FSGS. FSGS recurred in 76 (10.3%) patients. Younger age (P<0.001), nonwhite ethnicity (P=0.02), and having a live donor (P=0.02) were independent risk factors associated with recurrence. Median graft survival was significantly better for live donor compared with deceased donor grafts (14.8 versus 12.1 years; P<0.01). Disease recurrence predicted poor graft outcomes, with 52% (95% confidence interval, 40% to 63%) 5-year graft survival in the recurrence group compared with 83% (95% confidence interval, 79% to 86%) in the group without recurrent disease (P<0.001).

CONCLUSIONS

FSGS recurrence after kidney transplantation was more common in live donor kidneys. Despite this, graft survival in live donor recipients was significantly better for both children and adults with FSGS. We propose that live donor transplantation should not be avoided in patients with FSGS.

A retrospective review of telehealth services for children referred to a paediatric nephrologist

BACKGROUND

Telemedicine has emerged as an alternative mode of health care delivery over the last decade. To date, there is very limited published information in the field of telehealth and paediatric nephrology. The aim of this study was to review our experience with paediatric telenephrology in Queensland, Australia.

METHODS

A retrospective audit of paediatric nephrology telehealth consultations to determine the nature of the telehealth activity, reasons for referral to telehealth, and to compare costs and potential savings of the telehealth service.

RESULTS

During a ten-year period (2004 - 2013), 318 paediatric telenephrology consultations occurred for 168 patients (95 male) with the median age of 8 years (range 3 weeks to 24 years). Congenital anomalies of the kidney and urinary tract (30 %), followed by nephrotic syndrome (16 %), kidney transplant (12 %), and urinary tract infection (9 %) were the most common diagnoses. The estimated cost savings associated with telehealth were $31,837 in 2013 (average saving of $505 per consultation).

CONCLUSIONS

Our study suggests that paediatric telenephrology is a viable and economic method for patient assessment and follow up. The benefits include improved access to paediatric nephrology services for patients and their families, educational opportunity for the regional medical teams, and a substantial cost saving for the health care system.

Cytomegalovirus & Epstein Barr Virus serostatus as a predictor of the long-term outcome of kidney transplantation

AIM

Cytomegalovirus (CMV) and Epstein Barr Virus (EBV) disease and asymptomatic infection have been associated with poor outcomes in kidney transplantation. Recipients who acquire primary infection through transplantation from a seropositive donor may be at particular risk of complications. The primary aim of this study was to evaluate the relationship between donor/recipient (D/R) CMV and EBV serostatus pretransplant and allograft and patient survival in a large cohort of kidney transplant recipients.

METHODS

Data were obtained from the Australian and New Zealand Dialysis and Transplant Registry and the Australian and New Zealand Organ Donation Registry on 4516 first deceased donor kidney transplants performed between 1998 and 2010. Graft and patient survival were analysed using the Kaplan-Meier method.

RESULTS

Pretransplant CMV D/R serostatus was available for the whole cohort, with EBV D/R serostatus available for 2566 transplants (56.8%). Serostatus for both viruses was significantly associated with donor and recipient age and recipient smoking status. For both viruses the majority of transplants were in a D+/R+ serostatus setting: 45.3% for CMV and 77.9% for EBV. D/R serostatus for either virus did not have a significant effect on graft or patient survival.

CONCLUSION

We conclude that in the current era of viral prophylaxis and surveillance, long-term outcome for the kidney transplant population is unaffected by D/R CMV and EBV serostatus.

Post-transplant lymphoproliferative disorder: no relationship to recombinant human growth hormone use in Australian and New Zealand pediatric kidney transplant recipients

PTLD is a potentially life-limiting complication of pediatric transplantation. Previous registry-based studies in renal transplantation have suggested a link between rhGH use and PTLD. In this study, demographic and transplant data on those aged <18 yr and transplanted between 1991 and 2008 were collected from the ANZDATA Registry. Associations between gender, age at time of transplant, recipient CMV and EBV status, use of monoclonal antibody therapy, and use of rhGH were studied as potential predictors of PTLD. Among 650 transplants, there were 20 cases (3.1%) of PTLD, with half presenting within two yr post-transplant. Eight patients exposed to rhGH at any time developed PTLD, and this association was not statistically significant (RR = 1.5[0.6-3.4], p = 0.36). On multivariate analysis, there were no significant predictors for PTLD. In this study, previously identified potential risk factors were not identified as significant predictors for the development of PTLD. Although limited sample size may affect our ability to infer safety, this large retrospective cohort study does not suggest an increased risk of PTLD in pediatric kidney transplant recipients who received rhGH treatment.

Progressive multifocal leukoencephalopathy with gastrointestinal disease in a pediatric kidney transplant recipient

PML is a demyelinating disease of the central nervous system caused by infection with JCV. Several cases of PML in bone marrow and solid organ transplant recipients have been reported in recent years. JCV has been isolated from the gastrointestinal mucosa of immunocompromised patients, but there are no published reports of PML associated with symptomatic gastrointestinal involvement in kidney transplant recipients. We report a case of a nine-yr-old girl with a kidney transplant who developed a severe gastrointestinal illness causing pseudo-obstruction in association with PML. JCV was suspected as the causative agent in this patient by the detection of high JCV titer through PCR analysis of the cerebrospinal fluid and blood and positive staining for simian virus 40 in the colon. JCV intestinal infection should be considered in kidney transplant recipients presenting with intestinal pseudo-obstruction.

Chronic kidney disease and automatic reporting of estimated glomerular filtration rate: new developments and revised recommendations

The publication of the Australasian Creatinine Consensus Working Group's position statements in 2005 and 2007 resulted in automatic reporting of estimated glomerular filtration rate (eGFR) with requests for serum creatinine concentration in adults, facilitated the unification of units of measurement for creatinine and eGFR, and promoted the standardisation of assays. New advancements and continuing debate led the Australasian Creatinine Consensus Working Group to reconvene in 2010. The working group recommends that the method of calculating eGFR should be changed to the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) formula, and that all laboratories should report eGFR values as a precise figure to at least 90 mL/min/1.73 m(2). Age-related decision points for eGFR in adults are not recommended, as although an eGFR < 60 mL/min/1.73 m(2) is very common in older people, it is nevertheless predictive of significantly increased risks of adverse clinical outcomes, and should not be considered a normal part of ageing.If using eGFR for drug dosing, body size should be considered, in addition to referring to the approved product information. For drugs with a narrow therapeutic index, therapeutic drug monitoring or a valid marker of drug effect should be used to individualise dosing. The CKD-EPI formula has been validated as a tool to estimate GFR in some populations of non-European ancestry living in Western countries. Pending publication of validation studies, the working group also recommends that Australasian laboratories continue to automatically report eGFR in Aboriginal and Torres Strait Islander peoples. The working group concluded that routine calculation of eGFR is not recommended in children and youth, or in pregnant women. Serum creatinine concentration (preferably using an enzymatic assay for paediatric patients) should remain as the standard test for kidney function in these populations.

Original article anti-oxidant pathways are stimulated by mesenchymal stromal cells in renal repair after ischemic injury

BACKGROUND AIMS

Ischemia-reperfusion (IR) injury is a common cause of acute renal failure. Bone marrow (BM)-derived mesenchymal stromal cells (MSC) delivered after renal IR are renoprotective, but knowledge of the protective mechanism is still in development. This investigation analyzed the protective molecular mechanisms of MSC, in particular relating to modulated oxidative stress.

METHODS

In vivo and in vitro models of renal IR were analyzed with and without MSC. In vivo, adult male Sprague-Dawley rats were subjected to 40-min unilateral renal IR. Rat BM-derived MSC were administered at 24 h post-IR (IR + MSC). Other groups had IR but no MSC, or MSC but no ischemia (all groups n = 4). Apoptosis, inflammation, oxidative stress and reparative signal transduction molecules or growth factors were studied 4 days post-IR. In vitro, protection by MSC against oxidative stress (0.4 mm hydrogen peroxide) was investigated using rat renal tubular epithelial cells (NRK52E) with or without MSC in co-culture (tissue culture trans-well inserts), followed by similar analyses to the in vivo investigation.

RESULTS

In vivo, kidneys of IR + MSC animals had significantly increased cell proliferation/regeneration (cells positive for proliferating cell nuclear antigen, expression of epidermal growth factor), increased heme-oxygenase-1 (improved cell survival, anti-oxidant) and decreased 8-OHdG (decreased oxidative stress). In vitro, MSC delivered with oxidative stress significantly decreased apoptosis and Bax (pro-apoptotic protein), and increased mitosis and phospho-ERK1/2, thereby minimizing the damaging outcome and maximizing the regenerative effect after oxidative stress.

CONCLUSIONS

The benefits of MSC, in IR, were primarily pro-regenerative, sometimes anti-apoptotic, and novel anti-oxidant mechanisms were identified.

Review: Pharmacodynamic monitoring of immunosuppression in kidney transplantation

Advances in immunosuppressive therapies have improved kidney transplant outcomes. However, immunosuppressant drug-induced toxicities continue to reduce tolerability and impact patient and graft survival. A major ongoing challenge in kidney transplantation is to establish ways of tailoring immunosuppressant therapy so as to maintain efficacy while minimizing toxicity. Pharmacodynamic monitoring by direct measurement of immune cell function has the potential to personalize immunosuppression. The purpose of this review is to provide the clinician with an overview of the methodology and use of immune function monitoring in the field of kidney transplantation.

Epidemiology and outcomes of peritonitis in children on peritoneal dialysis in Australasia

Peritonitis is a common complication and major cause of morbidity in children on peritoneal dialysis. In this retrospective longitudinal study, we analysed data retrieved from the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA) on 167 patients aged less than 18 years of age who were treated with peritoneal dialysis during the period from October 2003 to December 2007. During this period there were 100 episodes of peritonitis in 57 patients (0.71 episodes/patient-year), with Gram-positive organisms most commonly isolated (44%). Peritonitis occurred frequently in the first 6 months after starting dialysis, with survival analysis showing peritonitis-free survival rates of 72%, 56% and 36% at 6 months, 1 year and 2 years respectively. Age was a weak predictor of peritonitis on univariate analysis, but previous peritonitis was the only significant predictor in a multivariate Cox proportional hazards model (adjusted hazard ratio 2.02; 95% CI: 1.20 to 3.40, p = 0.008). Peritonitis episodes infrequently resulted in relapse (5%), recurrence (7%) or the need for either temporary or permanent haemodialysis (5% and 7% respectively) and there were no patient deaths directly attributable to peritonitis. Compared with single organism peritonitis, polymicrobial peritonitis was not associated with any statistically significant differences in outcome. Further prospective studies are required to determine the most appropriate prophylactic measures and antibiotic regimens for use in pediatric patients.

Antibiotic prophylaxis and recurrent urinary tract infection in children

BACKGROUND

Antibiotics are widely administered to children with the intention of preventing urinary tract infection, but adequately powered, placebo-controlled trials regarding efficacy are lacking. This study from four Australian centers examined whether low-dose, continuous oral antibiotic therapy prevents urinary tract infection in predisposed children.

METHODS

We randomly assigned children under the age of 18 years who had had one or more microbiologically proven urinary tract infections to receive either daily trimethoprim-sulfamethoxazole suspension (as 2 mg of trimethoprim plus 10 mg of sulfamethoxazole per kilogram of body weight) or placebo for 12 months. The primary outcome was microbiologically confirmed symptomatic urinary tract infection. Intention-to-treat analyses were performed with the use of time-to-event data.

RESULTS

From December 1998 to March 2007, a total of 576 children (of 780 planned) underwent randomization. The median age at entry was 14 months; 64% of the patients were girls, 42% had known vesicoureteral reflux (at least grade III in 53% of these patients), and 71% were enrolled after the first diagnosis of urinary tract infection. During the study, urinary tract infection developed in 36 of 288 patients (13%) in the group receiving trimethoprim-sulfamethoxazole (antibiotic group) and in 55 of 288 patients (19%) in the placebo group (hazard ratio in the antibiotic group, 0.61; 95% confidence interval, 0.40 to 0.93; P = 0.02 by the log-rank test). In the antibiotic group, the reduction in the absolute risk of urinary tract infection (6 percentage points) appeared to be consistent across all subgroups of patients (P > or = 0.20 for all interactions).

CONCLUSIONS

Long-term, low-dose trimethoprim-sulfamethoxazole was associated with a decreased number of urinary tract infections in predisposed children. The treatment effect appeared to be consistent but modest across subgroups. (Australian New Zealand Clinical Trials Registry number, ACTRN12608000470392.)

Immunosuppression by mesenchymal stromal cells: from culture to clinic

Extensive in vitro studies have shown that multipotent mesenchymal stromal cells (MSC) can exert profound immunosuppressive effects via modulation of both cellular and innate immune pathways. Their ability to be readily isolated from a number of tissues and expanded ex vivo makes them attractive candidates for systemic immunosuppressive therapy. In this article, we will review recent experimental data on the mechanisms by which MSC inhibit the alloproliferative response and the clinical relevance for their potential use in hematopoietic stem cell transplantation, solid organ transplantation, and treatment of autoimmune diseases. While in vitro data consistently demonstrate the immunosuppressive capability of MSC, current studies in animals and humans suggest that MSC are less effective in producing systemic immunosuppression. Further mechanistic studies and randomized controlled trials using standardized cell populations are needed to define the optimal conditions for the use of MSC as immunotherapy.

Immunosuppression by placental indoleamine 2,3-dioxygenase: a role for mesenchymal stem cells

BACKGROUND/OBJECTIVES

Mesenchymal stem cells (MSC) can be isolated from human placenta and have the potential to contribute to the immunosuppressive properties of placental tissue. The objectives of this study were to investigate the phenotype and differentiation characteristics of MSC derived from human placenta and evaluate the role of the tryptophan degrading enzyme, indoleamine 2,3 dioxygenase (IDO), in mediating their immunosuppressive affect.

METHODS

MSC obtained from placental tissue (pMSC) were characterised using flow cytometry and tested for multipotency by determining differentiation into all mesenchymal lineages. The immunosuppressive properties of pMSC were tested in allogeneic mixed lymphocyte reactions and IDO expression and activity were measured by semi-quantitative real-time PCR and HPLC respectively.

RESULTS

Multipotent stem cells were isolated from placenta and displayed chondrogenic, osteogenic and limited adipogenic differentiation. Cell surface antigen expression of pMSC was similar to bone marrow MSC (bMSC) with lack of the haematopoietic and common leukocyte markers (CD34, CD45), and expression of adhesion (CD29, CD166, CD44) and stem cell (CD 90, CD105, CD73) markers. Placental MSC were suppressive of allogeneic T-cell proliferation, an effect which was intensified following IDO induction by IFN-gamma. Replenishment of tryptophan or treatment with the IDO-blocker, 1-methyl-tryptophan (1-MT), attenuated the immunosuppressive action of pMSC.

CONCLUSIONS

These results suggest that placental tissue contains MSC, which are phenotypically and functionally similar to bMSC, and that IDO is a key mediator of their immunosuppressive effect. Further investigation is needed to determine if pMSC function effects pregnancy outcome.

Mesenchymal stem cells: Immunobiology and therapeutic potential in kidney disease (Review Article)

Mesenchymal stem cells (MSC) are non-haematopoietic cells that are prevalent in the adult bone marrow but can also be isolated from a variety of other postnatal tissues. MSC are non-immunogenic and are immunosuppressive, with the ability to inhibit maturation of dendritic cells and suppress the function of naïve and memory T cells, B cells and NK cells. In addition to their immunomodulatory properties, MSC are capable of differentiating into various tissues of mesenchymal and non-mesenchymal origin and migrating to sites of tissue injury and inflammation to participate in tissue repair. A number of studies in animal models of cardiac injury, stroke and ischaemic renal injury have demonstrated the clinical potential of MSC in tissue regeneration and repair. MSC are currently being evaluated in various preclinical and clinical studies in humans and offer significant potential as a novel cellular therapy for tissue regeneration and immunological conditions. The present review focuses on the unique immunomodulatory and regenerative properties of MSC and their potential role in the treatment of kidney disease.

Estimated donor glomerular filtration rate is the most important donor characteristic predicting graft function in recipients of kidneys from live donors

We hypothesized that predictors of outcome in live donor transplants were likely to differ significantly from deceased donor transplants, in which cold ischaemia time, cause of donor death and other donor factors are the most important predictors. The primary aim was to explore the independent predictors of graft function in recipients of live donor kidneys (LDK). Our secondary aim was to determine which donor characteristics are the most useful predictors. A retrospective analysis was undertaken of all patients receiving live donor (n = 206) renal transplants at our institution between 31 May 1994 and 15 October 2002. Twelve patients were excluded from the analysis. Follow-up was completed on all patients until graft loss, death or 22 November 2003. We explored predictors of Nankivell glomerular filtration rate (GFR) at 6 months by multivariate linear regression. In the 194 patients studied, the mean recipient 6-month Nankivell GFR was 59 +/- 15 ml/min/1.73 m(2). Independent predictors of recipient GFR in at 6 months were donor Cockcroft-Gault GFR (CrCl; beta 0.16; CI 0.13 to 0.29; P < 0.0001), steroid resistant rejection (beta-6.07; CI -12.05 to -0.09; P = 0.006) and delayed graft function (DGF) (beta-10.0; CI -19.52 to -0.49; P = 0.039). Renal function in an LDK transplant recipients is predicted by donor GFR, episodes of steroid resistant rejection and DGF. Importantly, donor Cockcroft-Gault GFR is the most important characteristic for predicting the recipient renal function.

Long-term follow-up of patients with idiopathic infantile hypercalcaemia

Idiopathic infantile hypercalcaemia (IIH) is a rare disorder of unknown etiology that presents with hypercalcaemia in a child's first year of life. There is only a limited number of published reports of the natural history of this condition, and the long-term prognosis is largely unknown. The presentation, treatment and long-term follow-up of 11 children with IIH treated at our institution since 1993 are described. Hypercalcaemia resolved in the majority of children by the time they were 3 years of age, but nephrocalcinosis and persistent hypercalciuria were common, and, in some cases, urinary calcium excretion increased after initially becoming normal. This study suggests that clinical and biochemical abnormalities may persist for longer than previously reported and implies the need for ongoing surveillance of patients with IIH.

Isoprenylated proteins

Isoprenoids are synthesized in all living organisms and are incorporated into diverse classes of end-products that participate in a multitude of cellular processes relating to cell growth, differentiation, cytoskeletal function and vesicle trafficking. In humans, the non-sterol isoprenoids, farnesyl pyrophosphate and geranylgeranyl-pyrophosphate, are synthesized via the mevalonate pathway and are covalently added to members of the small G protein superfamily. Isoprenylated proteins have key roles in membrane attachment and protein functionality, have been shown to have a central role in some cancers and are likely also to be involved in the pathogenesis and progression of atherosclerosis and Alzheimer disease. This review details current knowledge on the biosynthesis of isoprenoids, their incorporation into proteins by the process known as prenylation and the complex regulatory network that controls these proteins. An improved understanding of these processes is likely to lead to the development of novel therapies that will have important implications for human health and disease.

Childhood urinary conditions

BACKGROUND

Urinary abnormalities are commonly detected in children and can be due to a wide range of conditions.

OBJECTIVE

This article provides an overview of common urinary abnormalities presenting in childhood to assist general practitioners in planning further investigation and management.

DISCUSSION

An initial assessment based upon a comprehensive history, examination and urinalysis should ensure that serious conditions are not overlooked and that unnecessary laboratory studies are not performed. Urinary dipstick testing should not be used to diagnose a urinary tract infection, but can often be used as a screen to exclude one. Isolated microscopic haematuria is only rarely a sign of significant kidney or urinary tract disease and nonpostural proteinuria is a more important diagnostic and prognostic finding that requires specialist assessment. In the majority of cases, the family can be reassured that the risk of significant kidney disease in asymptomatic children with minor urinary abnormalities is small.

Grandparent donors in paediatric renal transplantation

The outcome of transplantation from grandparent donors in comparison with parental donors in paediatric renal transplantation was evaluated in 53 living related donor (LRD) transplantations performed between January 1996 and August 2003. The donor in 13 cases (25%) was a grandparent (Gpar group), and the remaining donors formed the parent group (Par group). The median age of recipients in the Gpar group was 2.75 (1.7-10.6) years and in the Par group was 12.75 (2.4-22) years (P<0.0001). There was no evidence of a difference in patient and graft survival, glomerular filtration rate (GFR) after transplantation, or the number of biopsy proven episodes of rejection between the groups. Doses of prednisolone in the first year following transplantation were greater in recipients from Gpar donors, but the other immunosuppression doses were similar. The median age of donors in the Gpar group was 56 (50-67) years and in the Par group was 41 (27-58) years (P<0.0001). There was no evidence of a difference between the two donor groups in mean creatinine clearance at last follow-up. There were two major donor complications in the Gpar group and one in the Par group. There was no evidence that the length of stay differed between the two groups in either the donors or recipients. These results support the use of carefully selected healthy grandparents as LRDs in children. This option potentially allows for the use of parent donors for a subsequent transplantation.

Role of Isoprenoids in Cytoskeleton Integrity and Albumin Endocytosis by Opossum Kidney Cells

BACKGROUND

The actin cytoskeleton has been increasingly implicated in endocytic events that are involved in the reabsorption of filtered protein by the proximal tubule. Isoprenylated small G proteins have emerged as key regulators of the actin cytoskeleton. This study examines the role of isoprenoid intermediates in organization of the cytoskeleton, and the effect of modification of the cytoskeleton on albumin endocytosis.

METHODS

The effect of lovastatin on cytoskeleton morphology of opossum kidney cells (OK cells) was determined by staining with fluorescent isothiocyanate (FITC)-phalloidin followed by examination using confocal microscopy. Quantitative effects on albumin binding and uptake were determined using a well-established method.

RESULTS

Inhibition of isoprenoid synthesis by lovastatin led to morphological disruption of the cytoskeleton with a concentration-dependent decrease in albumin uptake into OK cells. Addition of mevalonate, but not cholesterol, ameliorated the effects of lovastatin on the cytoskeleton and albumin uptake. Selective inhibition of isoprenoid intermediates with a farnesyltransferase inhibitor suggests that geranylgeranylated proteins mediate cytoskeleton organization.

CONCLUSION

These results confirm the importance of cytoskeleton integrity in albumin endocytosis in renal proximal tubules. While the present data suggest that synthesis of isoprenoids via the mevalonate pathway is a critical step in maintenance of the cytoskeleton, the role of individual small G proteins in control of the cytoskeleton and other endocytic events is yet to be defined.

Factors influencing growth and final height after renal transplantation

Growth retardation occurs commonly in children and adolescents with chronic renal insufficiency. While some children exhibit catch-up growth following renal transplantation, for many children growth remains sub-optimal. The aim of the current study was to review the factors influencing growth and final height following renal transplantation. Data from all children who had a renal transplant performed between 1985 and 1998 at the Royal Melbourne and Royal Children's Hospitals, Melbourne (n = 85), were examined retrospectively. Two children who died in the first year post-transplant and one patient lost to follow-up within 6 months of their transplant were excluded. Children with multiple grafts had only growth following their most recent graft analyzed. The mean height standard deviation score (Ht-SDS) at the time of transplantation was -2.11 (range: -5.05 to 0.27), improving to -1.50 (range: -3.67 to 1.27) at 7 yr post-transplant. On univariate analysis, the dose of cyclosporin at 6 months and at 1 and 3 yr, and the graft function at 1 yr, had a significant positive correlation with the change in Ht-SDS (DeltaHt-SDS) at each of those time-points post-transplant. At all time-points there was a strong correlation between pretransplant height and subsequent growth. A sub-group of children who were 16 yr of age or older at December 1999, and who were considered to have reached their final height, were examined to determine predictors of final height. Multiple regression analysis of clinical and laboratory parameters from the sub-group of patients > or = 16 yr of age showed that height at the time of transplant, age at the time of transplant, and final glomerular filtration rate, were significant independent predictors of growth (r2 = 0.82, p = 0.01). In addition, the immunosuppressive regimen at 1, 3, and 5 yr post-transplant had a significant effect on growth. This study confirms the importance of each of these factors for post-transplant growth.

Clinical spectrum of Denys-Drash and Frasier syndrome

Denys-Drash syndrome (DDS) and Frasier syndrome (FS) are two related conditions caused by mutations of the Wilms tumor gene, WT1. Both syndromes are characterized by male pseudohermaphroditism, a progressive glomerulopathy, and the development of genitourinary tumors. DDS and FS have previously been distinguished by differences in nephropathy, with DDS patients demonstrating diffuse mesangial sclerosis (DMS) in contrast to focal and segmental glomerulosclerosis (FSGS) in FS patients. The clinicopathological features and genotype analysis of two patients with WT1 mutations are presented in this report. Genotype analysis of the first patient revealed a previously undescribed mutation in exon 8 of the WT1 gene. The second patient presented with a rapidly progressive nephropathy characterized histologically by DMS, but was found to have the genetic mutation seen in FS patients. A summary of all reported patients with the characteristic mutation associated with FS demonstrates the clinical overlap of this syndrome with DDS. This suggests that both these conditions should be considered as part of the spectrum of disease due to WT1 gene mutations rather than as separate diseases. Clinical classification remains important for prognosis, as the underlying renal disease appears to predict the progression of nephropathy independently of the genetic abnormality.

Evaluation and long-term outcome of pediatric renovascular hypertension

Seventeen children with renovascular hypertension were managed at the Royal Children's Hospital, Melbourne, over the 20-year period from 1975 to 1996. The age at presentation ranged from 10 days to 18 years. All children presented with severe hypertension with mean systolic blood pressure 7 standard deviations above age-matched averages and mean diastolic blood pressure 5.5 standard deviations above age-matched averages. Neurofibromatosis was the most common etiology (58% of patients) and there were no cases of Takayasu's arteritis. Patients underwent a variety of biochemical and imaging investigations but in all cases renal angiography was necessary for definitive diagnosis and for planning therapy. Ten of the 17 patients had surgical procedures performed. Percutaneous transluminal angioplasty was performed in four patients but led to cure in only one patient following thrombosis of the affected artery producing segmental renal infarction. Other vascular reconstructive procedures, including the use of autologous or synthetic bypass grafts and autotransplantation, produced cure of hypertension in 50% of children with improvement in a further 30%. The long-term outlook for children treated with surgical reconstructive procedures was excellent. One patient underwent surgery for avulsion of an arterial graft following a pubertal growth spurt. No other patient originally cured by surgery has required reoperation with no cases of restenosis at a mean follow-up of 11 years 3 months.

Familial occurrence of idiopathic infantile hypercalcemia

Idiopathic infantile hypercalcemia (IIH) is a rare cause of hypercalcemia in the 1st year of life and was initially considered part of a spectrum encompassing vitamin D intoxication, Williams syndrome, and idiopathic hypercalcemia. Identification of the gene for Williams syndrome now allows a clear separation of IIH from Williams syndrome. The inheritance and pathogenesis of IIH remains largely unknown, with only sporadic cases reported to date. This report describes a family with two siblings with IIH. The pedigree is consistent with autosomal recessive inheritance, but more complex inheritance is suggested by the occurrence of hypercalciuria in a number of family members. Although one affected patient demonstrated elevated 1,25-dihydroxyvitamin D(3) levels, no conclusions regarding the pathogenesis of this condition could be drawn.

Streptococcus pneumoniae-induced haemolytic uraemic syndrome

Haemolytic uraemic syndrome secondary to infection with neuraminidase producing Streptococcus pneumoniae is well recognised, but was previously considered to be rare. This case report describes the course of a 9-month-old male with pneumococcal pneumonia, T activation and haemolytic uraemic syndrome. The clinical features of three other cases treated in Southeast Queensland in the past 2 years and 12 previously reported cases are summarised. The widespread availability of rapid diagnostic testing for this entity should allow for increased recognition, enabling appropriate use of low plasma volume blood products with improved patient outcome.