BackgroundThe role of complement in the atypical form of hemolytic uremic syndrome (aHUS) has been investigated extensively in recent years. As the HUS-associated bacteria Shiga-toxin-producing Escherichia coli (STEC) can evade the complement system, we hypothesized that complement dysregulation is also important in infection-induced HUS.MethodsSerological profiles (C3, FH, FI, AP activity, C3d, C3bBbP, C3b/c, TCC, αFH) and genetic profiles (CFH, CFI, CD46, CFB, C3) of the alternative complement pathway were prospectively determined in the acute and convalescent phase of disease in children newly diagnosed with STEC-HUS or aHUS. Serological profiles were compared with those of 90 age-matched controls.ResultsThirty-seven patients were studied (26 STEC-HUS, 11 aHUS). In 39 % of them, including 28 % of STEC-HUS patients, we identified a genetic and/or acquired complement abnormality. In all patient groups, the levels of investigated alternative pathway (AP) activation markers were elevated in the acute phase and normalized in remission. The levels were significantly higher in aHUS than in STEC-HUS patients.ConclusionsIn both infection-induced HUS and aHUS patients, complement is activated in the acute phase of the disease but not during remission. The C3d/C3 ratio displayed the best discrepancy between acute and convalescent phase and between STEC-HUS and aHUS and might therefore be used as a biomarker in disease diagnosis and monitoring. The presence of aberrations in the alternative complement pathway in STEC-HUS patients was remarkable, as well.Electronic supplementary materialThe online version of this article (doi:10.1007/s00467-016-3496-0) contains supplementary material, which is available to authorized users.

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Background: Diuretics are administered to neonates to control fluid balance. We studied whether clinical doses affected kidney development and function and whether extrauterine growth retardation (EUGR) could be a modulator. Methods: Wistar rats were cross-fostered in normal food or food restricted litters at postnatal day (PND) 2 and treated daily with 0.9% NaCl, 5 mg/kg furosemide or 5 mg/kg hydrochlorothiazide (HCTZ) up to PND 8. Kidneys were evaluated on proliferation, apoptosis and a set of mRNA target genes at PND 8, glomerular- and glomerular generation count at PND 35, clinical pathology parameters at 3- and 9 months, neutrophil gelatinase-associated lipocalin at PND 8, 3 and 6 months, monthly blood pressure from 3 months onward and histopathology at study end. Results: Treatment with furosemide or HCTZ did not have relevant effects on measured parameters. EUGR resulted in lower body weight from day 3 onwards (-29% at weaning; p < 0.001, -10% at necropsy; p < 0.001), less glomerular generations (4.4 ± 0.32 vs. 5.0 ± 0.423; p = 0.025, males only), decreased glomerular numbers (27,861 ± 3,468 vs. 30,527 ± 4,096; p = 0.026), higher creatinine clearance (0.84 ± 0.1 vs. 0.77 ± 0.09 ml/min/kg; p = 0.047) at 3 months and lower plasma creatinine (25.7 ± 1.8 vs. 27.5 ± 2.8 µmol/l; p = 0.043) at 9 months. Conclusion: Furosemide and HCTZ did not influence kidney development or function when administered in a clinically relevant dose to rat pups at a stage of ongoing nephrogenesis. EUGR led to impaired kidney development but did not modify furosemide or HCTZ findings.

Our experiments showed that gentamicin at clinical levels did not disturb kidney development, ceftazidime can affect Renin expression, and extrauterine growth restriction impairs kidney development, but did not modulate potential drug toxicity. Birth Defects Research 109:1228-1235, 2017. © 2017 Wiley Periodicals, Inc.

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