Activation of protein kinase C (PKC) isoforms has been implicated in the pathogenesis of diabetic nephropathy. We showed earlier that PKC-␣ is activated in the kidneys of hyperglycemic animals. We now used PKC-␣ ؊/؊ mice to test the hypothesis that this PKC isoform mediates streptozotocin-induced diabetic nephropathy. We observed that renal and glomerular hypertrophy was similar in diabetic wild-type and PKC-␣ ؊/؊ mice. However, the development of albuminuria was almost absent in the diabetic PKC-␣ ؊/؊ mice. The hyperglycemia-induced downregulation of the negatively charged basement membrane heparan sulfate proteoglycan perlecan was completely prevented in the PKC-␣ ؊/؊ mice, compared with controls. We then asked whether transforming growth factor-␤1 (TGF-␤ 1 ) and/or vascular endothelial growth factor (VEGF) is implicated in the PKC-␣-mediated changes in the basement membrane. The hyperglycemia-induced expression of VEGF165 and its receptor VEGF receptor II (flk-1) was ameliorated in PKC-␣ ؊/؊ mice, whereas expression of TGF-␤ 1 was not affected by the lack of PKC-␣. Our findings indicate that two important features of diabetic nephropathy-glomerular hypertrophy and albuminuria-are differentially regulated. The glucose-induced albuminuria seems to be mediated by PKC-␣ via downregulation of proteoglycans in the basement membrane and regulation of VEGF expression. Therefore, PKC-␣ is a possible therapeutic target for the prevention of diabetic albuminuria.

Optimized fasting times improve the metabolic and hemodynamic condition during induction of anesthesia in children younger than 36 months of age.

PurposeParticulate contamination due to infusion therapy carries a potential health risk for intensive care patients.MethodsThis single-centre, prospective, randomized controlled trial assessed the effects of filtration of intravenous fluids on the reduction of complications in critically ill children admitted to a pediatric intensive care unit (PICU). A total of 807 subjects were randomly assigned to either a control (n = 406) or filter group (n = 401), with the latter receiving in-line filtration. The primary endpoint was reduction in the rate of overall complications, which included the occurrence of systemic inflammatory response syndrome (SIRS), sepsis, organ failure (circulation, lung, liver, kidney) and thrombosis. Secondary objectives were a reduction in the length of stay on the PICU and overall hospital stay. Duration of mechanical ventilation and mortality were also analyzed.FindingsAnalysis demonstrated a significant reduction in the overall complication rate (n = 166 [40.9 %] vs. n = 124 [30.9 %]; P = 0.003) for the filter group. In particular, the incidence of SIRS was significantly lower (n = 123 [30.3 %] vs. n = 90 [22.4 %]; P = 0.01). Moreover the length of stay on PICU (3.89 [95 % confidence interval 2.97−4.82] vs. 2.98 [2.33−3.64]; P = 0.025) and duration of mechanical ventilation (14.0 [5.6−22.4] vs. 11.0 [7.1−14.9] h; P = 0.028) were significantly reduced.ConclusionIn-line filtration is able to avert severe complications in critically ill patients. The overall complication rate during the PICU stay among the filter group was significantly reduced. In-line filtration was effective in reducing the occurrence of SIRS. We therefore conclude that in-line filtration improves the safety of intensive care therapy and represents a preventive strategy that results in a significant reduction of the length of stay in the PICU and duration of mechanical ventilation (ClinicalTrials.gov number: NCT00209768).Electronic supplementary materialThe online version of this article (doi:10.1007/s00134-012-2539-7) contains supplementary material, which is available to authorized users.

Albuminuria in diabetic nephropathy is due to endothelial dysfunction, a loss of negative charges in the basement membrane, and changes a of the slit-membrane diaphragm composition. We have recently shown that protein kinase C alpha (PKCalpha)-deficient mice are protected against the development of albuminuria under diabetic conditions. We here tested the hypothesis that PKCalpha mediates the hyperglycemia-induced downregulation of the slit-diaphragm protein nephrin. After 8 weeks of streptozotocin (STZ)-induced hyperglycemia the expression of glomerular nephrin was significantly reduced. In contrast, other slit-diaphragm proteins such as podocin and CD2AP were unaltered in diabetic state. In PKCalpha-/- mice, hyperglycemia-induced downregulation of nephrin was prevented. Podocin and CD2AP remained unchanged. In addition, the nephrin messenger RNA expression was also reduced in hyperglycemic wild-type mice but remained unaltered in PKCalpha-/- mice. We postulate that the underlying mechanism of the hyperglycemia-induced regulation of various proteins of the glomerular filtration barrier is a PKCalpha-dependent regulation of the Wilms' Tumor Suppressor (WT1) which previously has been shown to act as a direct transcription factor on the nephrin promoter. Our data suggest that PKCalpha activation may be an important intracellular signaling pathway in the regulation of nephrin expression and glomerular albumin permeability in the diabetic state.

BackgroundInfused particles induce thrombogenesis, impair microcirculation and modulate immune response. We have previously shown in critically ill children, that particle-retentive in-line filtration reduced the overall complication rate of severe events, length of stay and duration of mechanical ventilation. We now evaluated the influence of in-line filtration on different organ function and thereby elucidated the potential underlying pathophysiological effects of particle infusion.MethodsIn this single-centre, prospective, randomized controlled trial 807 critically ill children were assigned to either control (n = 406) or filter group (n = 401), the latter receiving in-line filtration for complete infusion therapy. Both groups were compared regarding the differences of incidence rates and its 95% confidence interval (CI) of different organ dysfunction as defined by the International Pediatric Sepsis Consensus Conference 2005.ResultsThe incidence rates of respiratory (−5.06%; 95% CI, −9.52 to −0.59%), renal (−3.87%; 95% CI, −7.58 to −0.15%) and hematologic (−3.89%; 95% CI, −7.26 to −0.51%) dysfunction were decreased in the filter group. No difference was demonstrated for the occurrence rates of cardiovascular, hepatic, or neurologic dysfunction between both groups.ConclusionsIn-line filtration has beneficial effects on the preservation of hematologic, renal and respiratory function in critically ill patients. The presented clinical data further support our hypothesis regarding potential harmful effects of particles. In critically ill patients infused particles may lead to further deterioration of the microcirculation, induce a systemic hypercoagulability and inflammation with consecutive negative effects on organ function.Trial registrationClinicalTrials.gov number; NCT00209768