Clustering of missense mutations in the C-terminal region of factor H in atypical hemolytic uremic syndrome

Hemolytic-uremic syndrome (HUS) is a microvasculature disorder leading to microangiopathic hemolytic anemia, thrombocytopenia, and acute renal failure. Most cases of HUS are associated with epidemics of diarrhea caused by verocytotoxin-producing bacteria, but atypical cases of HUS not associated with diarrhea (aHUS) also occur. Early studies describing the association of aHUS with deficiencies of factor H suggested a role for this complement regulator in aHUS. Molecular evidence of factor H involvement in aHUS was first provided by Warwicker et al., who demonstrated that aHUS segregated with the chromosome 1q region containing the factor H gene (HF1) and who identified a mutation in HF1 in a case of familial aHUS with normal levels of factor H. We have performed the mutational screening of the HF1 gene in a novel series of 13 Spanish patients with aHUS who present normal complement profiles and whose plasma levels of factor H are, with one exception, within the normal range. These studies have resulted in the identification of five novel HF1 mutations in four of the patients. Allele HF1 Delta exon2, a genomic deletion of exon 2, produces a null HF1 allele and results in plasma levels of factor H that are 50% of normal. T956M, W1183L, L1189R, and V1197A are missense mutations that alter amino acid residues in the C-terminal portion of factor H, within a region--SCR16-SCR20--that is involved in the binding to solid-phase C3b and to negatively charged cellular structures. This remarkable clustering of mutations in HF1 suggests that a specific dysfunction in the protection of cellular surfaces by factor H is a major pathogenic condition underlying aHUS.     

Methylprednisolone favourably alters plasma and urinary cytokine homeostasis and subclinical renal injury at cardiac surgery

Whilst elevated urinary transforming growth factor beta-1 (TGFbeta) is associated with chronic renal dysfunction its role in acute peri-operative renal dysfunction is unknown. In contrast, peri-operative increases in urinary IL-1 receptor antagonist (IL-1ra) and TNF soluble receptor-2 (TNFsr-2) mirror pro-inflammatory activity in the nephron and correlate with renal complications. Steroids modulate some plasma cytokines (decreasing TNFalpha, IL-8, IL-6 and increasing IL-10), whereas ability to reduce plasma and urinary TNFsr-2 and IL-1ra and peri-operative renal injury is unknown. Patients undergoing coronary artery bypass grafting with cardiopulmonary bypass (CPB) were randomised to receive methylprednisolone (n = 18) or placebo (n = 17) before induction of anaesthesia. Plasma and urinary pro- and anti-inflammatory cytokine balance was determined along with subclinical proximal tubular injury and dysfunction, measured by urinary N-acetyl-beta-d-glucosaminidase (NAG)/creatinine and alpha-1-microglobulin/creatinine ratios, respectively. In the control group compared with baseline, plasma IL-8, TNFalpha, IL-10, IL-1ra and TNFsr-2 were significantly elevated along with urinary IL-1ra, TNFsr-2 and TGFbeta1. Urinary NAG/creatinine and alpha-1-microglobulin/creatinine ratios rose from completion of revascularisation until 6 h with recovery at 24 h with a further rise in NAG/creatinine ratio at 48 h. Compared to placebo, the methylprednisolone group showed significantly reduced plasma IL-8, TNFalpha, IL-1ra and TNFsr-2 whereas plasma IL-10 increased. Compared to placebo, the methylprednisolone group demonstrated significantly reduced urinary NAG/creatinine ratio, TNFsr-2 and TGFbeta1 at 24 h whereas urinary alpha-1-microglobulin/creatinine ratios increased. CONCLUSIONS: Methylprednisolone administration during cardiac surgery significantly reduces plasma and urinary TNFsr-2 and IL-1ra, urinary TGFbeta1 and subclinical renal injury but not dysfunction.     

Shiga Toxin 1 Induces on Lipopolysaccharide-Treated Astrocytes the Release of Tumor Necrosis Factor-alpha that Alter Brain-Like Endothelium Integrity

The hemolytic uremic syndrome (HUS) is characterized by hemolytic anemia, thrombocytopenia and renal dysfunction. The typical form of HUS is generally associated with infections by Gram-negative Shiga toxin (Stx)-producing Escherichia coli (STEC). Endothelial dysfunction induced by Stx is central, but bacterial lipopolysaccharide (LPS) and neutrophils (PMN) contribute to the pathophysiology. Although renal failure is characteristic of this syndrome, neurological complications occur in severe cases and is usually associated with death. Impaired blood-brain barrier (BBB) is associated with damage to cerebral endothelial cells (ECs) that comprise the BBB. Astrocytes (ASTs) are inflammatory cells in the brain and determine the BBB function. ASTs are in close proximity to ECs, hence the study of the effects of Stx1 and LPS on ASTs, and the influence of their response on ECs is essential. We have previously demonstrated that Stx1 and LPS induced activation of rat ASTs and the release of inflammatory factors such as TNF-α, nitric oxide and chemokines. Here, we demonstrate that rat ASTs-derived factors alter permeability of ECs with brain properties (HUVECd); suggesting that functional properties of BBB could also be affected. Additionally, these factors activate HUVECd and render them into a proagregant state promoting PMN and platelets adhesion. Moreover, these effects were dependent on ASTs secreted-TNF-α. Stx1 and LPS-induced ASTs response could influence brain ECs integrity and BBB function once Stx and factors associated to the STEC infection reach the brain parenchyma and therefore contribute to the development of the neuropathology observed in HUS.     

Clinical presentation, complications and treatment of infection with verocytotoxin-producing Escherichia coli. Challenges for the clinician

Seventeen years after its recognition, outbreaks and sporadic infections attributed to Escherichia coli O157 continue to increase. Acute gastrointestinal, and the systemic complications haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP), are frequent and severe. Current challenges that face clinicians are the early recognition of infection, identification of risk factors for poor prognosis, determination of appropriate monitoring for the development of complications, establishment of a therapeutic strategy and, finally, advice for patients about their long-term prognosis. Clinical features which, in combination, have been shown to distinguish E. coli O157 infection from other enteric pathogens are a history of bloody diarrhoea, visibly bloody stools, absence of fever, a leucocyte count greater than 10 x 10(9) l(-1) and abdominal tenderness on physical examination. The most consistent risk factors for the development of HUS/TTP are the extremes of age and a raised leucocyte count. Bloody diarrhoea and 'antimotility' drugs are also likely to be important risk factors. Recent evidence from the central Scotland outbreak suggests that individuals who are taking drugs that reduce gastric acidity or antibiotics at the time of infection with E. coli O157, or who have a short incubation period, may also be at increased risk of progression to HUS/TTP. Clinical management, in particular the role of antibiotics in gastrointestinal infection, remains controversial, and retrospective assessment of the 1996 outbreaks from central Scotland and Japan only adds to this controversy. Therapeutic plasma exchange is a promising treatment for adults who develop HUS/TTP, but its role has yet to be determined definitively, either in a randomized controlled trial or by an international register of cases. Significant chronic sequelae of infection occur, particularly irritable bowel syndrome after uncomplicated gastrointestinal infection, and renal failure after HUS/TTP. Their frequency and severity are likely to become evident over the next decade.     

A case-control study to evaluate urinary tract complications in radical hysterectomy

BACKGROUND: This study has evaluated urinary tract injuries and dysfunction after Radical Hysterectomy (RH) performed in patients with cervical cancer and has compared the cystometric parameters and urinary complications occurring in these patients with those occurring in patients who had undergone Simple Hysterectomy (SH). PATIENTS AND METHODS: A prospective case-control study was conducted to evaluate urinary tract injuries (intra-operative and post-operative) and dysfunction in 50 patients undergoing RH for cervical cancer and to compare them with the same parameters in 50 patients who underwent SH for benign disease. RESULTS: Mean age in the RH group was 46.3 years and in the SH group was 50.1 (p = 0.63). There were no bladder and urethral injuries in either group of patients. There was one intra-operative ureteral injury in the RH patients but none in those who underwent SH. (p < 0.05). In the two weeks after surgery, 15% of RH patients and 11% of SH patients had experienced a urinary tract infection urinary tract infection (p = 0.61). Two week after surgery 62% of RH patients had no urinary symptoms, compared to 84% in the SH group who did (p < 0.02). Urinary residual volume, first urinary sensation and maximal bladder capacity were higher in the RH group, but this was not statistically significant. The only case of a urinary fistula appeared in a patient who received 5000 cGy radiation therapy pre-operatively, but this spontaneously healed after 3 weeks of catheterization. CONCLUSIONS: Intra-operative and post-operative urinary tract complications are comparable in patients undergoing RH and SH and an expert gynaecological oncologist might be able to further decrease complications. However, radiation therapy before surgery may increase the risk of complications.     

Suppression of secondary hyperparathyroidism in children with chronic renal failure by high dose phosphate binders: calcium carbonate versus aluminium hydroxide.

Secondary hyperparathyroidism was suppressed over a period of one year in 12 children with chronic renal failure by using a regimen of mild dietary phosphate restriction and high dose phosphate binders. The patients were randomised to receive either aluminium hydroxide or calcium carbonate by mouth for six months and then crossed over to the other medication. Vitamin D (dihydrotachysterol) dosage was unchanged. Serum parathyroid hormone concentrations were reduced to within the normal range, urinary cyclic adenosine monophosphate values fell, plasma phosphate concentrations decreased, and the theoretical renal phosphate threshold increased significantly. Transiliac bone biopsy findings improved in four patients with adequate suppression of parathyroid hormone concentrations, deteriorated in two patients who were not compliant, and did not change in five patients in whom initial bone disease was mild. Growth velocity improved significantly. There was no difference in the clinical response, biochemical changes, or incidence of complications during treatment with the two agents. In view of the risk of aluminium toxicity the use of high dose calcium carbonate with dietary phosphate restriction and vitamin D supplementation is recommended in the control of secondary hyperparathyroidism in children with chronic renal failure.     

Role of BSP bilirubin binding protein on p-aminohippurate transport in rat kidney

The frequency, severity, and outcome of flutamide-induced hepatic injury were prospectively evaluated in 55 patients with prostate cancer who received 125 mg of flutamide 3 times a day (daily dose: 375 mg) combined with an agonistic analogue of luteinizing hormone-releasing hormone. In addition, we examined plasma and urine concentrations of flutamide and its major metabolites 4 weeks after the beginning of flutamide therapy, and evaluated their significance in predicting flutamide-induced hepatic dysfunction. Hepatic function could be assessed in 50 patients and hepatic dysfunction during therapy was observed in 9 patients (18%); 3 patients (6%) were classified as having moderate liver dysfunction and 6 (12%) were classified as having mild liver dysfunction. The steady-state plasma levels of flutamide and its biologic active metabolite, hydroxyflutamide (OH-Flu), were not related to hepatic dysfunction. However, the concentration of another major metabolite, 4-nitro-3-(trifluoromethyl)phenylamine (FLU-1) was considerably higher in 2 patients who developed clinically significant hepatic dysfunction. These findings suggest that clinically significant hepatic dysfunction could be induced in patients with compromised flutamide metabolism, which leads to a high concentration of FLU-1. Based on results of this study, we propose that plasma FLU-1 levels are one of the predictive factors for flutamide-induced hepatic dysfunction. This hypothesis will be confirmed in a large-scale study.     

Cytokine phenotype,genotype, and renal outcomes at cardiac surgery

BackgroundCardiac surgery modulates pro- and anti-inflammatory cytokine balance involving plasma tumour necrosis factor alpha (TNFα) and interleukin-10 (IL-10) together with urinary transforming growth factor beta-1 (TGFβ1), interleukin-1 receptor antagonist (IL1ra) and tumour necrosis factor soluble receptor-2 (TNFsr2). Effects on post-operative renal function are unclear. We investigated if following cardiac surgery there is a relationship between cytokine (a) phenotype and renal outcome; (b) genotype and phenotype and (c) genotype and renal outcome. Since angiotensin-2 (AG2), modulates TGFβ1 production, we determined whether angiotensin converting enzyme insertion/deletion (ACE I/D) genotype affects urinary TGFβ1 phenotype as well as renal outcome.MethodsIn 408 elective cardiac surgery patients we measured pre- and 24 h post-operative urinary TGFβ-1, IL1ra and TNFsr2 and pre- and 2 h post-operative plasma TNFα and IL-10. Post-operative responses were compared for each cytokine in patients grouped according to presence or absence of renal dysfunction defined as a drop from baseline eGFR of greater than 25% (as calculated by the method of modification of diet in renal disease (MDRD)) occurring (1) within the first 24 and (2) 48 postoperative hours (early renal dysfunction), (3) on the fifth postoperative day (late renal dysfunction) or (4) at any time throughout the 5 day postoperative period (early and late combined). Patient genotype was determined for TNF/G-308A, TGFβ1-509 C/T, IL10/G-1082A and ACE I/D.ResultsPost-operative plasma IL-10 and urinary TGFβ1 responses were significantly higher in patients who developed early renal dysfunction. IL1ra and TNFsr2 responses were significantly lower 24 h post-operatively in patients who developed late renal dysfunction. Genotype did not alter cytokine phenotype or outcome.Conclusions/inferencesCytokine profiling may help predict early and late renal dysfunction. Genotypes studied did not alter phenotype or outcome.     

Risk Factors for Development of Hemolytic Uremic Syndrome in a Cohort of Adult Patients with STEC 0104:H4 Infection

The outbreak of Shiga toxin producing E.coli O104:H4 in northern Germany in 2011 was one of the largest worldwide and involved mainly adults. Post-diarrheal hemolytic uremic syndrome (HUS) occurred in 22% of STEC positive patients. This study’s aim was to assess risk factors for HUS in STEC-infected patients and to develop a score from routine hospital parameters to estimate patient risks for developing HUS. In a cohort analysis, adult patients with STEC infection were included in five participating hospitals in northern Germany between May and July 2011. Clinical data were obtained from questionnaires and medical records, laboratory data were extracted from hospitals’ electronic data systems. HUS was defined as thrombocytopenia, hemolytic anemia and acute renal dysfunction. Random forests and multivariate logistic regression were used to identify risk factors for HUS and develop a score using the estimated coefficients as weights. Among 259 adults with STEC infection, vomiting (OR 3.48,95%CI 1.88–6.53), visible blood in stools (OR 3.91,95%CI1.20–16.01), age above 75 years (OR 3.27, 95%CI 1.12–9.70) and elevated leukocyte counts (OR 1.20, 95%CI 1.10–1.31, per 1000 cells/mm³) were identified as independent risk factors for HUS. A score using these variables has an area under the ROC curve of 0.74 (95%CI 0.68–0.80). Vomiting, visible blood in stools, higher leukocyte counts, and higher age indicate increased risk for developing HUS. A score using these variables might help to identify high risk patients who potentially benefit from aggressive pre-emptive treatment to prevent or mitigate the devastating consequences of HUS.     

Diabetes mellitus following paediatric renal transplantation: a single centre experience

BACKGROUND/AIMS: Post-transplant diabetes mellitus (PTDM) has a variably reported incidence of 4-41% among adults and children. We describe our recent experience of four children with PTDM in a paediatric renal transplantation centre. METHODS: We undertook a retrospective analysis of the glycaemic status of all paediatric patients undergoing renal transplantation at our centre in the 2-year study period. The clinical features and investigations of those who developed PTDM were further reviewed. RESULTS: Five episodes of PTDM occurred in 4/32 children. There was a variable onset and a wide range of symptoms. Investigations revealed a combination of insulinopenia with peripheral insulin resistance. Insulin therapy was required for variable durations with resolution of PTDM in four episodes. PTDM did not adversely affect the renal graft function. CONCLUSION: PTDM requires increased awareness among paediatric nephrologists and endocrinologists for early recognition and prompt effective intervention.     

Antibody response to Shiga toxins in Argentinean children with enteropathic hemolytic uremic syndrome at acute and long-term follow-up periods

Shiga toxin (Stx)-producing Escherichia coli (STEC) infection is associated with a broad spectrum of clinical manifestations that include diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Systemic Stx toxemia is considered to be central to the genesis of HUS. Distinct methods have been used to evaluate anti-Stx response for immunodiagnostic or epidemiological analysis of HUS cases. The development of enzyme-linked immunosorbent assay (ELISA) and western blot (WB) assay to detect the presence of specific antibodies to Stx has introduced important advantages for serodiagnosis of HUS. However, application of these methods for seroepidemiological studies in Argentina has been limited. The aim of this work was to develop an ELISA to detect antibodies against the B subunit of Stx2, and a WB to evaluate antibodies against both subunits of Stx2 and Stx1, in order to analyze the pertinence and effectiveness of these techniques in the Argentinean population. We studied 72 normal healthy children (NHC) and 105 HUS patients of the urban pediatric population from the surrounding area of Buenos Aires city. Using the WB method we detected 67% of plasma from NHC reactive for Stx2, but only 8% for Stx1. These results are in agreement with the broad circulation of Stx2-expressing STEC in Argentina and the endemic behavior of HUS in this country. Moreover, the simultaneous evaluation by the two methods allowed us to differentiate acute HUS patients from NHC with a great specificity and accuracy, in order to confirm the HUS etiology when pathogenic bacteria were not isolated from stools.     

Evidence of Uncoupling between Renal Dysfunction and Injury in Cardiorenal Syndrome: Insights from the BIONICS Study

Objective

The objective of the study was to assess urinary biomarkers of renal injury for their individual or collective ability to predict Worsening renal function (WRF) in patients with acutely decompensated heart failure (ADHF).

Methods

In a prospective, blinded international study, 87 emergency department (ED) patients with ADHF were evaluated with biomarkers of cardiac stretch (B type natriuretic peptide [BNP] and its amino terminal equivalent [NT-proBNP], ST2), biomarkers of renal function (creatinine, estimated glomerular filtration rate [eGFR]) and biomarkers of renal injury (plasma neutrophil gelatinase associated lipocalin [pNGAL], urine kidney injury molecule-1 [KIM-1], urine N-acetyl-beta-D-glucosaminidase [NAG], urine Cystatin C, urine fibrinogen). The primary endpoint was WRF.

Results

26% developed WRF; baseline characteristics of subjects who developed WRF were generally comparable to those who did not. Biomarkers of renal function and urine biomarkers of renal injury were not correlated, while urine biomarkers of renal injury correlated between each other. Biomarker concentrations were similar between patients with and without WRF except for baseline BNP. Although plasma NGAL was associated with the combined endpoint, none of the biomarker showed predictive accuracy for WRF.

Conclusions

In ED patients with ADHF, urine biomarkers of renal injury did not predict WRF. Our data suggest that a weak association exists between renal dysfunction and renal injury in this setting (Clinicaltrials.gov NCT#0150153).     

Continuous renal replacement therapy in children post-hematopoietic stem cell transplantation: the present and the future

Allogeneic hematopoietic stem cell transplantation (HSCT) use has expanded markedly to treat different disorders like hematologic malignancies, immunodeficiency, and inborn errors of metabolism. However, it is commonly associated with complications that limit the benefit of this therapy. Acute renal failure occurs commonly after HSCT and results in increased risk of mortality. In many instances, children post-HSCT develop acute renal insufficiency in the context of other organ failure, necessitating intensive care unit admission for management. Recently, continuous renal replacement therapy (CRRT) has emerged as the favored modality of renal replacement therapy in the care of critically ill children who are hemodynamically unstable. Currently, CRRT is being utilized more often in the care of critically ill post- HSCT children to treat renal failure or to prevent fluid overload (FO). FO > 20% has been shown in many studies to be an independent risk of mortality in critically ill children and therefore, many clinicians will initiate this therapy due to FO even without overt renal failure. CRRT may be beneficial in disease processes as acute lung injury due to removal of fluid. CRRT results in improved oxygenation in post-HSCT children with acute lung injury and this improvement is sustained for at least 48 hours after initiation of this therapy. Survival in post-HSCT children requiring this therapy ranges from 17% to 45%, however, long term survival is still poor. This review will discuss current practice of CRRT in children post-HSCT, as well as future directions.     

Alternative pathway activation of complement by Shiga toxin promotes exuberant C3a formation that triggers microvascular thrombosis

Shiga toxin (Stx)-producing E.coli O157:H7 has become a global threat to public health; it is a primary cause of diarrhea-associated hemolytic uremic syndrome (HUS), a disorder of thrombocytopenia, microangiopathic hemolytic anemia, and acute renal failure with thrombi occluding renal microcirculation. In this study, we explored whether Stx triggers complement-dependent microvascular thrombosis in in vitro and in vivo experimental settings of HUS. Stx induced on human microvascular endothelial cell surface the expression of P-selectin, which bound and activated C3 via the alternative pathway, leading to thrombus formation under flow. In the search for mechanisms linking complement activation and thrombosis, we found that exuberant complement activation in response to Stx generated an increased amount of C3a that caused further endothelial P-selectin expression, thrombomodulin (TM) loss, and thrombus formation. In a murine model of HUS obtained by coinjection of Stx2 and LPS and characterized by thrombocytopenia and renal dysfunction, upregulation of glomerular endothelial P-selectin was associated with C3 and fibrin(ogen) deposits, platelet clumps, and reduced TM expression. Treatment with anti-P-selectin Ab limited glomerular C3 accumulation. Factor B-deficient mice after Stx2/LPS exhibited less thrombocytopenia and were protected against glomerular abnormalities and renal function impairment, indicating the involvement of complement activation via the alternative pathway in the glomerular thrombotic process in HUS mice. The functional role of C3a was documented by data showing that glomerular fibrin(ogen), platelet clumps, and TM loss were markedly decreased in HUS mice receiving C3aR antagonist. These results identify Stx-induced complement activation, via P-selectin, as a key mechanism of C3a-dependent microvascular thrombosis in diarrhea-associated HUS.     

Nonsteroidal anti-inflammatory drugs. Proposed guidelines for monitoring toxicity.

The most common toxicities of nonsteroidal anti-inflammatory drugs (NSAIDs) are gastropathy, renal dysfunction, and liver function abnormalities. We outline an approach to monitoring patients on long-term NSAID therapy, focusing on the early detection of complications. Gastropathy caused by NSAID use is more common in elderly patients or those with a history of dyspepsia, peptic ulcer disease, or alcohol abuse. Fecal occult blood testing and hemograms are less accurate in detecting gastropathy than direct visualization but are convenient and relatively inexpensive. We recommend the periodic use of these tests to detect NSAID-induced acute or chronic blood loss. Renal toxicity is seen in patients with preexisting renal disease or functional volume depletion and in the elderly. Complications include renal insufficiency, hyponatremia, hyperkalemia, and protein-uria. Renal function should be monitored during the first few weeks of NSAID therapy, especially in high-risk patients, with periodic testing thereafter. Hepatic toxicity is less common but warrants occasional determinations of alanine aminotransferase levels. Elderly patients and those with renal insufficiency or alcohol abuse have a higher risk of complications. Nonsteroidal anti-inflammatory drugs should be used cautiously in those patients at high risk for complications. Strategies can be used to limit toxicity. Patients taking these drugs long term should be monitored periodically for signs of blood loss, renal dysfunction, and hepatic dysfunction.     

The association between the total antioxidant potential of plasma and the presence of coronary heart disease and renal dysfunction in patients with NIDDM

Oxidative stress may be an important pathogenetic factor in the development of diabetic vascular complications. The total antioxidative potential of plasma reflects the ability of an individual to resist oxidative stress. We measured the plasma total peroxyl radical-trapping potential (TRAP) and the concentrations of four plasma chain-breaking antioxidants in 81 patients with non-insulin-dependent diabetes mellitus (NIDDM) nine years after diagnosis and in 102 well-matched non-diabetic control subjects. The association between the total antioxidative potential and the presence of coronary heart disease (CHD) and diabetic kidney disease were also studied. There were no significant differences in plasma TRAP between NIDDM patients and control subjects (1250 ± 199 vs. 1224 ± 198 μM). Nor were there any significant differences in the concentrations of plasma uric acid, ascorbic acid, α-tocopherol, and protein thiols between NIDDM patients and control subjects. Patients with a low glomerular filtration rate and/or high urinary albumin excretion had elevated plasma uric acid. Plasma TRAP was not, however, associated with renal dysfunction. The plasma of NIDDM patients with CHD had a significantly higher value of unidentified antioxidative potential than that of patients without CHD. This relation was strongly dependent upon smoking. In conclusion, these data demonstrate that there are no major defects in the antioxidative potential of plasma caused by NIDDM per se. CHD and diabetic renal dysfunction were not associated with changes in plasma TRAP.     

TLR9 Mediates Remote Liver Injury following Severe Renal Ischemia Reperfusion

Ischemia reperfusion injury is a common cause of acute kidney injury and is characterized by tubular damage. Mitochondrial DNA is released upon severe tissue injury and can act as a damage-associated molecular pattern via the innate immune receptor TLR9. Here, we investigated the role of TLR9 in the context of moderate or severe renal ischemia reperfusion injury using wild-type C57BL/6 mice or TLR9KO mice. Moderate renal ischemia induced renal dysfunction but did not decrease animal well-being and was not regulated by TLR9. In contrast, severe renal ischemia decreased animal well-being and survival in wild-type mice after respectively one or five days of reperfusion. TLR9 deficiency improved animal well-being and survival. TLR9 deficiency did not reduce renal inflammation or tubular necrosis. Rather, severe renal ischemia induced hepatic injury as seen by increased plasma ALAT and ASAT levels and focal hepatic necrosis which was prevented by TLR9 deficiency and correlated with reduced circulating mitochondrial DNA levels and plasma LDH. We conclude that TLR9 does not mediate renal dysfunction following either moderate or severe renal ischemia. In contrast, our data indicates that TLR9 is an important mediator of hepatic injury secondary to ischemic acute kidney injury.     

Urinary tract infections in children. An update.

Urinary tract infection is a common and frequently recurring condition in children. The susceptibility of the host, the presence of urinary tract abnormalities, and the virulence of the urinary pathogens are of primary importance in the development of the infection. Renal parenchymal scarring, hypertension, and renal insufficiency are well-established complications of the infection in children. To reduce the risk of renal damage, diagnosis and treatment must be prompt. The diagnosis demands radiologic evaluation of the urinary tract in all boys, all children younger than 5 years, all patients with voiding dysfunction, and school-aged girls with recurrent infection to identify those patients with vesicoureteral reflux, obstruction, or other urinary tract abnormalities. Both voiding cystourethrography and renal ultrasonography are the initial examinations to use to determine the next appropriate study. Children with vesicoureteral reflux or with recurrent urinary tract infections should receive prophylactic antibiotic therapy and should be observed closely to prevent renal scarring.     

Atypical hemolytic uremic syndrome

Hemolytic uremic syndrome (HUS) is defined by the triad of mechanical hemolytic anemia, thrombocytopenia and renal impairment. Atypical HUS (aHUS) defines non Shiga-toxin-HUS and even if some authors include secondary aHUS due to Streptococcus pneumoniae or other causes, aHUS designates a primary disease due to a disorder in complement alternative pathway regulation. Atypical HUS represents 5 -10% of HUS in children, but the majority of HUS in adults. The incidence of complement-aHUS is not known precisely. However, more than 1000 aHUS patients investigated for complement abnormalities have been reported. Onset is from the neonatal period to the adult age. Most patients present with hemolytic anemia, thrombocytopenia and renal failure and 20% have extra renal manifestations. Two to 10% die and one third progress to end-stage renal failure at first episode. Half of patients have relapses. Mutations in the genes encoding complement regulatory proteins factor H, membrane cofactor protein (MCP), factor I or thrombomodulin have been demonstrated in 20-30%, 5-15%, 4-10% and 3-5% of patients respectively, and mutations in the genes of C3 convertase proteins, C3 and factor B, in 2-10% and 1-4%. In addition, 6-10% of patients have anti-factor H antibodies. Diagnosis of aHUS relies on 1) No associated disease 2) No criteria for Shigatoxin-HUS (stool culture and PCR for Shiga-toxins; serology for anti-lipopolysaccharides antibodies) 3) No criteria for thrombotic thrombocytopenic purpura (serum ADAMTS 13 activity > 10%). Investigation of the complement system is required (C3, C4, factor H and factor I plasma concentration, MCP expression on leukocytes and anti-factor H antibodies; genetic screening to identify risk factors). The disease is familial in approximately 20% of pedigrees, with an autosomal recessive or dominant mode of transmission. As penetrance of the disease is 50%, genetic counseling is difficult. Plasmatherapy has been first line treatment until presently, without unquestionable demonstration of efficiency. There is a high risk of post-transplant recurrence, except in MCP-HUS. Case reports and two phase II trials show an impressive efficacy of the complement C5 blocker eculizumab, suggesting it will be the next standard of care. Except for patients treated by intensive plasmatherapy or eculizumab, the worst prognosis is in factor H-HUS, as mortality can reach 20% and 50% of survivors do not recover renal function. Half of factor I-HUS progress to end-stage renal failure. Conversely, most patients with MCP-HUS have preserved renal function. Anti-factor H antibodies-HUS has favourable outcome if treated early.     

Comparison of immediate and delayed free TRAM flap breast reconstruction in patients receiving postmastectomy radiation therapy.

Tumor pathologic features and the extent of nodal involvement dictate whether radiation therapy is given after mastectomy for breast cancer. It is generally well accepted that radiation negatively influences the outcome of implant-based breast reconstruction. However, the long-term effect of radiation therapy on the outcome of breast reconstruction with the free transverse rectus abdominis myocutaneous (TRAM) flap is still unclear. For patients who need postmastectomy radiation therapy, the optimal timing of TRAM flap reconstruction is controversial. This study compares the outcome of immediate and delayed free TRAM flap breast reconstruction in patients who received postmastectomy radiation therapy.All patients at The University of Texas M. D. Anderson Cancer Center who received postmastectomy radiation therapy and who also underwent free TRAM flap breast reconstruction between January of 1988 and December of 1998 were included in the study. Patients who received radiation therapy before delayed TRAM flap reconstruction were compared with patients who underwent immediate TRAM flap reconstruction before radiation therapy. Early and late complications were compared between the two groups. Early complications included vessel thrombosis, partial or total flap loss, mastectomy skin flap necrosis, and local wound-healing problems, whereas late complications included fat necrosis, volume loss, and flap contracture of free TRAM breast mounds. Late complications were evaluated at least 1 year after the completion of radiation therapy for patients who had delayed reconstruction and at least 1 year after reconstruction for patients who had immediate reconstruction.During the study period, 32 patients had immediate TRAM flap reconstruction before radiation therapy and 70 patients had radiation therapy before TRAM flap reconstruction. Mean follow-up times for the immediate reconstruction and delayed reconstruction groups were 3 and 5 years, respectively. The mean radiation dose was 50 Gy in the immediate reconstruction group and 51 Gy in the delayed reconstruction group.One complete flap loss occurred in the delayed reconstruction group, and no flap loss occurred in the immediate reconstruction group. The incidence of early complications did not differ significantly between the two groups. However, the incidence of late complications was significantly higher in the immediate reconstruction group than in the delayed reconstruction group (87.5 percent versus 8.6 percent; p = 0.000). Nine patients (28 percent) in the immediate reconstruction group required an additional flap to correct the distorted contour from flap shrinkage and severe flap contraction.These findings indicate that, in patients who are candidates for free TRAM flap breast reconstruction and need postmastectomy radiation therapy, reconstruction should be delayed until radiation therapy is complete.