Endothelial nitric oxide synthase gene T-786C and 27-bp repeat gene polymorphisms in retinopathy of prematurity

PURPOSE: Retinopathy of prematurity (ROP), which is associated with abnormal retinal vessel development, is the leading cause of visual loss in preterm infants. Endothelial nitric oxide synthase (eNOS) is believed to play a central role in both retinal angiogenesis and vasculogenesis. The aim of this study was to investigate functional genetic polymorphisms of eNOS in the pathogenesis of ROP. METHODS: eNOS T(−786)C and 27-bp repeat (eNOS, b: wild-type, a: mutant) genotypes were determined using allele-specific polymerase chain reaction in 105 low birth weight (LBW) preterm infants treated for ROP (treated group). A control group was set up and composed of 127 LBW infants with stage 1 or 2 ROP that did not not require treatment (untreated group). RESULTS: The genotype distribution of eNOS 27-bp repeat polymorphism was found to significantly differ (p=0.015) between the two groups, whereas the genotype distribution of eNOS T(−786)C did not differ (p=0.984) between the groups. There was no difference in the distribution of either the “a” allele (p=0.153) nor of the C allele (p=0.867) in a groups comparison. Multiple logistic regression analysis revealed that male gender (p=0.046) and eNOS aa genotype (p=0.047 versus ab genotype and p=0.022 versus bb genotype) were significantly associated severe ROP that required treatment. The haplotype estimations based on the detected genotype distributions showed that the prevalence of aT and bT haplotypes was significantly increased in the group treated for ROP. CONCLUSIONS: Functional eNOS 27-bp repeat polymorphism might be associated with the risk of severe ROP, however we found no association between the eNOS T(−786)C and the pathogenesis of ROP

Diagnostic performance and reference values of novel biomarkers of paediatric heart failure

Objective: Biomarkers play a pivotal role in heart failure (HF) management. Reference values and insights from studies in adults cannot be extrapolated to the paediatric population due to important differences in pathophysiology and compensatory reserve. We assessed the diagnostic utility of four novel biomarkers in paediatric HF. Methods: Midregional (MR) pro-atrial natriuretic peptide (proANP), soluble ST2 (sST2), growth differentiation factor-15 (GDF-15), MR-pro-adrenomedullin (proADM) and N-terminal pro-B natriuretic peptide (NT-proBNP) were measured in 114 patients and 89 controls. HF was defined as the presence of HF symptoms and/or abnormal systolic ventricular function. Receiver-operating characteristics were plotted, and the area under the curve (AUC) was measured. This was repeated for subgroups with cardiomyopathy and congenital heart disease (CHD). Ventricular systolic function was measured by magnetic resonance or echocardiography. Reference values were calculated according to the current guidelines. Results: The AUC for diagnosing HF was 0.76 for MR-proANP (CI 0.70 to 0.84) and 0.82 for NT-proBNP (CI 0.75 to 0.88). These parameters performed similarly in the subgroups with CHD and cardiomyopathy. By contrast, MR-proADM, GDF-15 and sST2 performed poorly. When used in conjunction with NT-proBNP, no parameter added significantly to its diagnostic accuracy. NT-proBNP, MR-proANP, GDF-15 and sST2 could accurately discriminate between patients with preserved and patients with poor functional status. In a subset of patients with dilated cardiomyopathy, NT-proBNP, MR-proANP, MR-proADM and GDF-15 were associated with poor LV function. Conclusions: MR-proANP could accurately detect HF in children and adolescents. Its diagnostic performance was comparable with that of NT-proBNP, regardless of the underlying condition. Reference values are presented

RAGE does not contribute to renal injury and damage upon ischemia/reperfusion-induced injury.

Item does not contain fulltextThe receptor for advanced glycation end products (RAGE) mediates a variety of inflammatory responses in renal diseases, but its role in renal ischemia/reperfusion (I/R) injury is unknown. We showed that during renal I/R, RAGE ligands HMGB1 and S100B are expressed. However, RAGE deficiency does not affect renal injury and function upon I/R-induced injury

Toll-Like Receptor Signaling and SIGIRR in Renal Fibrosis upon Unilateral Ureteral Obstruction

Innate immune activation via IL-1R or Toll-like receptors (TLR) contibutes to acute kidney injury but its role in tissue remodeling during chronic kidney disease is unclear. SIGIRR is an inhibitor of TLR-induced cytokine and chemokine expression in intrarenal immune cells, therefore, we hypothesized that Sigirr-deficiency would aggravate postobstructive renal fibrosis. The expression of TLRs as well as endogenous TLR agonists increased within six days after UUO in obstructed compared to unobstructed kidneys while SIGIRR itself was downregulated by day 10. However, lack of SIGIRR did not affect the intrarenal mRNA expression of proinflammatory and profibrotic mediators as well as the numbers of intrarenal macrophages and T cells or morphometric markers of tubular atrophy and interstitial fibrosis. Because SIGIRR is known to block TLR/IL-1R signaling at the level of the intracellular adaptor molecule MyD88 UUO experiments were also performed in mice deficient for either MyD88, TLR2 or TLR9. After UUO there was no significant change of tubular interstitial damage and interstitial fibrosis in neither of these mice compared to wildtype counterparts. Additional in-vitro studies with CD90+ renal fibroblasts revealed that TLR agonists induce the expression of IL-6 and MCP-1/CCL2 but not of TGF-β, collagen-1α or smooth muscle actin. Together, postobstructive renal interstitial fibrosis and tubular atrophy develop independent of SIGIRR, TLR2, TLR9, and MyD88. These data argue against a significant role of these molecules in renal fibrosis

Is the inflammasome a potential therapeutic target in renal disease?

The inflammasome is a large, multiprotein complex that drives proinflammatory cytokine production in response to infection and tissue injury. Pattern recognition receptors that are either membrane bound or cytoplasmic trigger inflammasome assembly. These receptors sense danger signals including damage-associated molecular patterns and pathogen-associated molecular patterns (DAMPS and PAMPS respectively). The best-characterized inflammasome is the NLRP3 inflammasome. On assembly of the NLRP3 inflammasome, post-translational processing and secretion of pro-inflammatory cytokines IL-1β and IL-18 occurs; in addition, cell death may be mediated via caspase-1. Intrinsic renal cells express components of the inflammasome pathway. This is most prominent in tubular epithelial cells and, to a lesser degree, in glomeruli. Several primary renal diseases and systemic diseases affecting the kidney are associated with NLRP3 inflammasome/IL-1β/IL-18 axis activation. Most of the disorders studied have been acute inflammatory diseases. The disease spectrum includes ureteric obstruction, ischaemia reperfusion injury, glomerulonephritis, sepsis, hypoxia, glycerol-induced renal failure, and crystal nephropathy. In addition to mediating renal disease, the IL-1/ IL-18 axis may also be responsible for development of CKD itself and its related complications, including vascular calcification and sepsis. Experimental models using genetic deletions and/or receptor antagonists/antiserum against the NLRP3 inflammasome pathway have shown decreased severity of disease. As such, the inflammasome is an attractive potential therapeutic target in a variety of renal diseases

Increased immunogenicity is an integral part of the heat shock response following renal ischemia.

Renal ischemia increases tubular immunogenicity predisposing to increased risk of kidney allograft rejection. Ischemia-reperfusion not only disrupts cellular homeostasis but also induces the cytoprotective heat shock response that also plays a major role in cellular immune and defense processes. This study therefore tested the hypothesis that upregulation of renal tubular immunogenicity is an integral part of the heat shock response after renal ischemia. Expressions of 70 kDa heat shock protein (Hsp70), major histocompatibility complex (MHC) class II, and intercellular adhesion molecule-1 (ICAM-1) were assessed in normal rat kidney (NRK) cells following ATP depletion (antimycin A for 3 h) and heat (42°C for 24 h). In vitro, transient Hsp70 transfection and heat shock factor-1 (HSF-1) transcription factor decoy treatment were performed. In vivo, ischemic renal cortex was investigated in Sprague-Dawley rats following unilateral renal artery clamping for 45 min and 24 h recovery. Upregulation of Hsp70 was closely and significantly correlated with upregulation of MHC class II and/or ICAM-1 following ATP depletion and heat injury. Bioinformatics analysis searching the TRANSFAC database predicted HSF-1 binding sites in these genes. HSF-1 decoy significantly reduced the expression of immunogenicity markers in stressed NRK cells. In the in vivo rat model of renal ischemia, concordant upregulation of MHC class II molecules and Hsp70 suggests biological relevance of this link. The results demonstrate that upregulation of renal tubular immunogenicity is an integral part of the heat shock response after renal ischemia. Bioinformatic analysis predicted a molecular link to tubular immunogenicity at the level of the transcription factor HSF-1 that was experimentally verified by HSF-1 decoy treatment. Future studies in HSF-1 knockout mice are needed

Dexamethasone protects from renal ischemia/reperfusion injury: A possible association with SGK-1

Previous experimental data suggest that steroids might have protective effects during hypoxic/ischemic injury of various organs. In this study, the association between dexamethason (Dexa) treatment and the anti-apoptotic SGK-1 was tested in ischemic renal injury. In vitro, HK-2 cells were exposed to 24 h hypoxia, and the effect of Dexa incubation on SGK-1 expression / activation and on cell death was studied. In an in vivo rat model of unilateral renal IR, animals were treated with Dexa, and serum renal function parameters, tissue injury and SGK-1 expression and localization were examined after different reperfusion times (2 h, 4 h and 24 h). Dexa at a dose of 2 mg/L exerted a protective effect on cell survival assessed by LDH release and vital staining paralleled by marked up-regulation of SGK-1. In rats, 2 mg/kg Dexa treatment 24 h prior to ischemia resulted in less severe tissue injury and ameliorated urea nitrogen levels 24 h after reperfusion. Furthermore, SGK-1 expression and phosphorylation were higher in Dexa animals demonstrated by Western blot and immunofluorescence technique. Our results provide novel data on the signalling mechanism of Dexa under hypoxia / ischemia and further support that Dexa emerges as an attractive pharmacological agent for the prevention of ischemic injury