Proteomic analysis of mononuclear cells of patients with minimal-change nephrotic syndrome of childhood

Background/Aims. Recently, peripheral blood mononuclear cell transcriptome analysis has identified genes that are upregulated in relapsing minimal-change nephrotic syndrome (MCNS). In order to investigate protein expression in peripheral blood mononuclear cells (PBMC) from relapsing MCNS patients, we performed proteomic comparisons of PBMC from patients with MCNS in relapse and controls. Methods. PBMC from a total of 20 patients were analysed. PBMC were taken from five patients with relapsing MCNS, four in remission, five patients with other glomerular diseases and six controls. Two dimensional electrophoresis was performed and proteome patterns were compared. Results. Automatic heuristic clustering analysis allowed us to pool correctly the gels from the MCNS patients in the relapse and in the control groups. Using hierarchical population matching, nine spots were found to be increased in PBMC from MCNS patients in relapse. Four spots were identified by mass spectrometry. Three of the four proteins identified (l-plastin, α-tropomyosin and annexin III) were cytoskeletal-associated proteins. Using western blot and immunochemistry, l-plastin and α-tropomyosin 3 concentrations were found to be enhanced in PBMC from MCNS patients in relapse. Conclusions. These data indicate that a specific proteomic profile characterizes PBMC from MCNS patients in relapse. Proteins involved in PBMC cytoskeletal rearrangement are increased in relapsing MCNS. We hypothesize that T-cell cytoskeletal rearrangement may play a role in the pathogenesis of MCNS by altering the expression of cell surface receptors and by modifying the interaction of these cells with glomerular cell

Antenatal oligohydramnios of renal origin: long-term outcome

Background. Prognosis of fetuses with renal oligohydramnios (ROH) is often still regarded as poor. Neonatal complications and the long-term follow-up of fetuses with ROH in two pediatric centres are described. Method. 23 fetuses (16 males, 7 females) were included as patients. Primary diseases included congenital anomalies of the kidney and urinary tract (n = 16), autosomal recessive polycystic kidney disease (n = 4) and renal tubular dysgenesis (n = 3). The analysis includes retrospective chart review. Results. Seven children died (30%), the majority (n = 4, 17%) within the neonatal period due to pulmonary hypoplasia and renal insufficiency. Fourteen patients (61%) required postnatal mechanical ventilation for a median of 4 (range 1-60) days; 11 infants had an associated pneumothorax. All 16 surviving children have chronic kidney disease (CKD) at a current median age of 5.7 years (range 0.5-14.5), managed conservatively in eight patients [median glomerular filtration rate 51 (range 20-78) ml/min/1.73 m2]. Eight patients reached end-stage renal disease at a median age of 0.3 years (range 2 days to 8.3 years), including one patient with pre-emptive kidney transplantation. Five of the patients requiring dialysis underwent successful renal transplantation at a median age of 3.5 years (range 2.5-4). Growth was impaired in seven children requiring growth hormone treatment. Cognitive and motor development was normal in 12 (75%) of the 16 patients and showed a delay in four children, including two with associated syndromal features. Conclusion. ROH is not always associated with a poor prognosis and long-term outcome in survivors is encouraging. The high incidence of neonatal complications and long-term morbidity due to CKD requires a multidisciplinary management of these childre

Developmental changes in the L-arginine/nitric oxide pathway from infancy to adulthood: plasma asymmetric dimethylarginine levels decrease with age

Background: The L-arginine/nitric oxide (NO) pathway has multiple physiological functions including vasodilation, inhibition of platelet aggregation and neurotransmission. Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of all known NO synthase isoforms, has adverse effects on renal and cardiovascular function in adults. It is unknown whether ADMA might also exert similar effects in younger individuals including infants. Also, reference data for important members of the L-arginine/NO family, notably ADMA and the NO metabolites, nitrite and nitrate, in infancy are lacking. Methods: In the present study, we investigated the status of the L-arginine/NO pathway in 34 healthy volunteers aged 2days to 24years by measuring the concentration of ADMA, nitrite, nitrate and L-arginine in plasma and urine using gas chromatography-mass spectrometry and gas chromatography-tandem mass spectrometry methods. Results: We found that ADMA levels in plasma decreased with age (Pearson correlation coefficient r=-0.619, p<0.001). In contrast, urinary excretion of nitrate (r=0.471, p=0.036) and nitrite increased with age (r=0.484, p=0.037). Conclusions: Our study suggests that in infants ADMA biosynthesis accompanied by an inhibition of NO synthesis is higher than in adults and diminishes considerably with age. Clin Chem Lab Med 2007;45:1525-3

Recurrence of severe steroid dependency in cyclosporin A-treated childhood idiopathic nephrotic syndrome

Background. In patients with steroid-dependent nephrotic syndrome (SDNS), long-term remission (LTR) can usually be achieved with cyclosporin A (CSA), after alternative treatment with cytotoxic drugs or levamisole has failed. Nevertheless, severe SDNS recurs in some patients despite CSA maintenance therapy. Few data are available on the clinical course and treatment strategies in these patients. Methods. We carried out a retrospective chart analysis of 46 patients with SDNS treated with CSA, after failure of cyctotoxic treatment with cyclophosphamide (CPO). Median age at primary manifestation was 3.0 years (range 0.8-6.9) and median current age is 20.4 years (range 8.6-29.1). Patients were recruited from three centres caring for a total of 186 patients with steroid-sensitive nephrotic syndrome. Results. In 14 of the 46 patients (30%; 10 male), severe SDNS recurred again despite CSA maintenance therapy. Seven patients relapsed beyond the age of 18 years. Nine of 14 patients received a further course of cytotoxic treatment as first intervention: six were treated with chlorambucil (CLA) and three with CPO. Four of the CLA-treated patients remained in LTR in contrast to none after CPO. Five patients received levamisole after CSA: only one went into LTR, while in one other CSA could be discontinued although further relapses occurred. One further patient was switched to CLA after levamisole, finally inducing LTR. Overall, six patients required two or more drugs, and in four of these CSA maintenance ultimately had to be restarted. Conclusion. We conclude that SDNS can recur in patients despite CSA maintenance therapy. Treatment strategies for this subgroup of patients are complex and should be standardized to optimize long-term outcome. A subgroup of patients with childhood SDNS continues to relapse into adulthoo

Elevated asymmetric dimethylarginine (ADMA) and inverse correlation between circulating ADMA and glomerular filtration rate in children with sporadic focal segmental glomerulosclerosis (FSGS)

Background. Steroid-resistant nephrotic syndromes (NS) with focal and segmental glomerulosclerosis (FSGS) can be differentiated into sporadic and syndromic forms. In sporadic NS, a circulating FSGS-factor is discussed in the pathogenesis and is thought to inhibit the synthesis of nitric oxide (NO) from l-arginine by blocking the NO synthase (NOS). Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of all types of NOS. In a previous study we did not find an elevation of ADMA in a syndromic form of FSGS, the Schimke-immuno-osseous dysplasia. Here we report for the first time data on the l-arginine/NO pathway in sporadic FSGS of childhood. Methods. Nine children (5 to 18 years of age) suffering from sporadic FSGS and age-matched healthy controls were investigated. ADMA in plasma and urine as well as l-arginine in plasma were determined by gas chromatography-tandem mass spectrometry. The NO metabolites nitrate and nitrite were measured in plasma and urine by gas chromatography-mass spectrometry (GC-MS). The ADMA metabolite dimethylamine (DMA) was measured in urine by GC-MS. Results. We found elevated plasma levels of ADMA in children suffering from sporadic FSGS compared to healthy controls (851 nmol/L versus 684 nmol/L, P = 0.008). An inverse correlation between ADMA and glomerular filtration rate (GFR) was found in sporadic FSGS (Pearson's correlation coefficient −0.784, P = 0.012). Conclusion. Our study suggests that ADMA synthesis is elevated in sporadic FSGS. This finding argues for the involvement of ADMA in the pathogenesis of this disease in childhoo

Urinary proteome pattern in children with renal Fanconi syndrome

Background. The renal Fanconi syndrome (FS) is characterized by renal glucosuria, loss of electrolytes, bicarbonate and lactate, generalized hyperaminoaciduria and low-molecular-weight proteinuria. We studied the urinary low-molecular-weight proteome to identify excreted peptides indicative of a pathogenetic mechanism leading to tubular dysfunction. Methods. We established a urinary proteome pattern using capillary electrophoresis mass spectrometry (CE-MS) of 7 paediatric patients with cystinosis and 6 patients with ifosfamide-induced FS as the study group, and 54 healthy volunteers and 45 patients suffering from other renal diseases such as lupus nephritis (n = 8), focal segmental glomerulosclerosis (n = 27), minimal change disease (n = 7) and membranous glomerulonephritis (n = 3) as controls. Consequently, we conducted a blinded study consisting of 11 FS patients and 9 patients with renal disease other than FS. Additionally, we applied this pattern to 294 previously measured samples of patients with different renal diseases. Amino acid sequences of some marker proteins were obtained. Results. Specificity for detecting FS was 89% and sensitivity was 82%. The marker peptides constituting the proteome pattern are fragments derived from osteopontin, uromodulin and collagen alpha-1. Conclusions. CE-MS can be used to diagnose FS in paediatric patients and might be a future tool for the non-invasive diagnosis of FS. The reduced amount of the marker proteins osteopontin and uromodulin indicates loss of function of tubular excretion in all patients suffering from FS regardless of the underlying cause. In addition, the six different fragments of the collagen alpha-1 (I) chain were either elevated or reduced in the urine. This indicates a change of proteases in collagen degradation as observed in interstitial fibrosis. These changes were prominent irrespectively of the stages of FS. This indicates fibrosis as an early starting pathogenetic reason for the development of renal insufficiency in FS patient

Shotgun Lipidomics Discovered Diurnal Regulation of Lipid Metabolism Linked to Insulin Sensitivity in Nondiabetic Men.

CONTEXT: Meal timing affects metabolic homeostasis and body weight, but how composition and timing of meals affect plasma lipidomics in humans is not well studied. OBJECTIVE: We used high throughput shotgun plasma lipidomics to investigate effects of timing of carbohydrate and fat intake on lipid metabolism and its relation to glycemic control. DESIGN: 29 nondiabetic men consumed (1) a high-carb test meal (MTT-HC) at 09.00 and a high-fat meal (MTT-HF) at 15.40; or (2) MTT-HF at 09.00 and MTT-HC at 15.40. Blood was sampled before and 180 minutes after completion of each MTT. Subcutaneous adipose tissue (SAT) was collected after overnight fast and both MTTs. Prior to each investigation day, participants consumed a 4-week isocaloric diet of the same composition: (1) high-carb meals until 13.30 and high-fat meals between 16.30 and 22:00 or (2) the inverse order. RESULTS: 12 hour daily lipid patterns showed a complex regulation by both the time of day (67.8%) and meal composition (55.4%). A third of lipids showed a diurnal variation in postprandial responses to the same meal with mostly higher responses in the morning than in the afternoon. Triacylglycerols containing shorter and more saturated fatty acids were enriched in the morning. SAT transcripts involved in fatty acid synthesis and desaturation showed no diurnal variation. Diurnal changes of 7 lipid classes were negatively associated with insulin sensitivity, but not with glucose and insulin response or insulin secretion. CONCLUSIONS: This study identified postprandial plasma lipid profiles as being strongly affected by meal timing and associated with insulin sensitivity

Case report: Early onset de novo FSGS in a child after kidney transplantation—a successful treatment

BackgroundEarly onset de novo focal segmental glomerular sclerosis (FSGS) in the kidney allograft in patients without FSGS in the native kidney is a rare disorder in children. It usually occurs mostly beyond the first year after kidney transplantation and often leads to graft loss. Standardized treatment protocols have not yet been established.Case descriptionWe describe a boy with early onset de novo FSGS in the transplanted kidney and non-selective glomerular proteinuria (maximum albumin-to-creatinine ratio of 3.8 g/g; normal range, ≤0.03 g/g creatinine). Manifestation occurred at 30 days posttransplant and was accompanied by a significant graft dysfunction (eGFR 61 ml/min per 1.73 m2). Treatment with 25 sessions of plasmapheresis over 14 weeks and three consecutive days of methylprednisolone pulse therapy (10 mg/kg per day) followed by oral prednisolone as rejection prophylaxis (3.73 mg/m2 per day) led to sustained remission of proteinuria (albumin-to-creatinine ratio of 0.028 g/g) and normalization of graft function (eGFR 92 ml/min per 1.73 m2) after 14 weeks. The follow-up period was 36 months.ConclusionsThis case underlines the efficacy of immunosuppressive and antibody eliminating therapy in early onset de novo FSGS after kidney transplantation

Long-Term Transplantation Outcomes in Patients With Primary Hyperoxaluria Type 1 Included in the European Hyperoxaluria Consortium (OxalEurope) Registry

INTRODUCTION: In primary hyperoxaluria type 1 (PH1), oxalate overproduction frequently causes kidney stones, nephrocalcinosis, and kidney failure. As PH1 is caused by a congenital liver enzyme defect, combined liver–kidney transplantation (CLKT) has been recommended in patients with kidney failure. Nevertheless, systematic analyses on long-term transplantation outcomes are scarce. The merits of a sequential over combined procedure regarding kidney graft survival remain unclear as is the place of isolated kidney transplantation (KT) for patients with vitamin B6-responsive genotypes. METHODS: We used the OxalEurope registry for retrospective analyses of patients with PH1 who underwent transplantation. Analyses of crude Kaplan–Meier survival curves and adjusted relative hazards from the Cox proportional hazards model were performed. RESULTS: A total of 267 patients with PH1 underwent transplantation between 1978 and 2019. Data of 244 patients (159 CLKTs, 48 isolated KTs, 37 sequential liver–KTs [SLKTs]) were eligible for comparative analyses. Comparing CLKTs with isolated KTs, adjusted mortality was similar in patients with B6-unresponsive genotypes but lower after isolated KT in patients with B6-responsive genotypes (adjusted hazard ratio 0.07, 95% CI: 0.01–0.75, P = 0.028). CLKT yielded higher adjusted event-free survival and death-censored kidney graft survival in patients with B6-unresponsive genotypes (P = 0.025, P < 0.001) but not in patients with B6-responsive genotypes (P = 0.145, P = 0.421). Outcomes for 159 combined procedures versus 37 sequential procedures were comparable. There were 12 patients who underwent pre-emptive liver transplantation (PLT) with poor outcomes. CONCLUSION: The CLKT or SLKT remains the preferred transplantation modality in patients with PH1 with B6-unresponsive genotypes, but isolated KT could be an alternative approach in patients with B6-responsive genotypes