H7-associated Hemolytic Uremic Syndrome Research Articles

Dysregulation of Angiopoietin 1 and 2 in Escherichia coli O157:H7 Infection and the Hemolytic-Uremic Syndrome

Escherichia coli O157:H7-associated hemolytic-uremic syndrome (HUS) is characterized by profound prothrombotic abnormalities. Endothelial dysfunction, manifested as dysregulation of angiopoietins 1 and 2 (Ang-1/2), could underlie HUS pathophysiology. We measured Ang-1/2 in 77 children with E. coli O157:H7 infection. Ang-1, Ang-2, and the Ang-2/Ang-1 ratio were significantly different in HUS vs the pre-HUS phase of illness or uncomplicated infection. Angiopoietin dysregulation preceded HUS and worsened as HUS developed. In vitro exposure of human microvascular endothelial cells to Shiga toxin recapitulated the in vivo observations. Angiopoietin regulation is profoundly affected before and during HUS, reflecting that subclinical endothelial dysfunction precedes overt microangiopathy.

Heightened Proteolysis of Plasma ADAMTS13 Antigen in Patients with Thrombotic Thrombocytopenic Purpura.

A total of 140 subjects with thrombotic thrombocytopenic purpura (TTP)/hemolytic-uremic syndrome (HUS), in which 25 were Upshaw-Schulman syndrome (USS, belonged to 20 families), 107 were acquired TTP (96 idiopathic and 11 drug-induced), and 8 were acquired O157:H7-associated HUS, were analyzed on their plasma ADAMTS13 antigen (:AGN), using 3 novel anti-ADAMTS13 murine monoclonal IgG antibodies (A10, C7, and WH2-1–11). Epitope of these antibodies resided on the disintegrin-like, 7th/8th thrombospondin-1, and 4th thrombospondin-1 domains, respectively. The WH2-11–1 alone was immunoreactive on western blot (WB) under reducing conditions. Further, in a static assay system, A10 totally and C7 partially inhibited ADAMTS13 activity (:ACT), but WH2-11–1 did not. A sandwich ELISA using C7 as the 1st antibody and biotinylated A10 as the 2nd antibody revealed a significant reduction of plasma ADAMTS13:AGN level in patients with acquired TTP, but a considerable variation in those with USS, suggesting that the quantitative ELISA has a limited diagnostic value.A quantitative and semi-qualitative WB analysis using A10 and WH2-11-1, however, demonstrated that normal plasmas had a 190/180 kD-doublet band under non-reducing conditions. A size exclusion chromatography of normal plasma was able to separate a 190 kD-protein from a 180 kD-band, and the former turned to be a single 200 kD-band on WB under reducing conditions, but in the latter such protein band was completely invisible, indicating that the 180 kD-band had undergone proteolytic modification. All the patient plasmas with USS and a roughly half of those with acquired TTP had a broad and fuzzy ~190/180 kD-band on WB before reduction, but it almost entirely disappeared after reduction. In patient plasmas with acquired HUS, however, the pattern of WB analysis was indistinguishable from that of the normal subjects.Aforementioned WB analysis was then performed on a girl of acquired TTP with high-titer inhibitors against ADAMTS13, using the sequential plasma samples obtained during the past 3 years, and confirmed complete normalization of the abnormal ADAMTS13:AGN patterns in accord to the increase of plasma ADAMTS13:ACT, together with her clinical improvements. Protease(s) responsible for this heightened cleavage is currently under investigation.

Is severe deficiency of ADAMTS-13 specific for thrombotic thrombocytopenic purpura? Yes

Is severe deficiency of ADAMTS-13 specific for thrombotic thrombocytopenic purpura? Yes

Circulating granulocyte colony-stimulating factor, C-X-C, and C-C chemokines in children with Escherichia coli O157:H7 associated hemolytic uremic syndrome.

Leukocytes are implicated in the pathogenesis of diarrhea-associated hemolytic uremic syndrome (D(+) HUS). We hypothesized that increased circulating levels of granulocyte colony-stimulating factor (G-CSF), and the chemokines epithelial cell-derived neutrophil-activating protein-78 (ENA-78), growth related oncogen-alpha (GRO-alpha), macrophage inflammatory protein-1beta (MIP-1beta), and monocyte chemotactic protein-1 (MCP-1) are related to the severity of illness in Escherichia coli O157:H7 infections. We compared the circulating concentrations of these mediators in the course of E. coli O157:H7 enteritis, hemorrhagic colitis, and HUS. Our data show that, on admission, children with HUS presented 10-fold abnormally increased levels of G-CSF (p < 0.007), 3-fold increased MIP-1beta concentrations (p < 0.001), and 2-fold lower values of ENA-78 (p < 0.0001). One week later, a further 4-fold decrease in ENA-78 concentration was noted (p < 0.0001) whereas MIP-1beta levels returned to normal. HUS patients requiring peritoneal dialysis showed 6-fold increased G-CSF (p < 0.001) and 5-fold decreased ENA-78 (p < 0.001) levels. On admission, children with uncomplicated O157:H7 hemorrhagic colitis (HC) presented 3-fold abnormally increased concentrations of G-CSF (p < 0.001) and MIP-1beta (p < 0.0001). Those with O157:H7 enteritis but no bloody stools showed higher rates of abnormal GRO-alpha, MIP-1beta, and MCP-1 measurements than children with O157:H7 HC or HUS: GRO-alpha (50% enteritis, 36% HC, 17% HUS; p < 0.06), MIP-1beta (40% enteritis, 22% HC, 11% HUS; p < 0.02), MCP-1 (77% enteritis, 20% HC, 18% HUS; p < 0.0001). The data indicates that GRO-alpha, MIP-1beta, and MCP-1 are produced during E. coli O157:H7 enteritis, whether or not HC or HUS develops. Our data suggest that children with O157:H7 associated HUS may present abnormally increased circulating levels of G-CSF and decreased ENA-78 concentrations. The mechanisms responsible for leukocytes recruitment in O157:H7 infections are unclear and await further studies.

Circulating Granulocyte Colony-Stimulating Factor, C-X-C, and C-C Chemokines in Children with Escherichia Coli O157:H7 Associated Hemolytic Uremic Syndrome

Circulating Granulocyte Colony-Stimulating Factor, C-X-C, and C-C Chemokines in Children with Escherichia Coli O157:H7 Associated Hemolytic Uremic Syndrome

Platelet-activating factor and Escherichia coliO157:H7 infections.

The role of platelet-activating factor (PAF), a phospholipid inflammatory mediator, in Escherichia coli O157:H7-associated hemolytic uremic syndrome (HUS) is unknown. PAF is synthesized by diverse cells and is degraded by PAF-acetylhydrolase (PAF-AH). Deficient PAF-AH activity results from a G-->T transversion at position 994 of exon 9. We examined children infected with E. coliO157:H7 to determine if PAF levels or the PAF-AH ( G994T) mutation reflects the risk of developing HUS. Plasma PAF concentrations were determined using chloroform/methanol extraction, thin layer chromatography purification, and scintillation proximity assay in 10 patients with uncomplicated infection (UI), 10 infected patients who subsequently developed HUS (pre-HUS), 5 HUS patients, and 8 healthy controls. The PAF-AH ( G994T) allele frequency was determined in 52 UI children, 15 with HUS, and 11 controls. Wilcoxon rank sum tests were performed to test differences in location (median) of pairs of groups. PAF levels were higher in the UI ( P=0.04) and pre-HUS ( P=0.01) groups than in healthy controls. No subject had the PAF-AH ( G994T) allele. Thus, elevated plasma PAF levels occur in E. coliO157:H7-infected children, even without HUS, but diminish when HUS develops. The PAF-AH ( G994T) allele does not contribute to the risk of developing HUS.

Soluble Fas and soluble Fas-ligand in children with Escherichia coli O157:H7–associated hemolytic uremic syndrome

We measured soluble Fas-ligand (sFas-L) and soluble Fas (sFas) levels by sandwich enzyme-linked immunosorbeny assay and compared them among (1) healthy controls (n = 11), (2) children with hemorrhagic colitis (HC) caused by a non–verotoxin-producing pathogen (n = 23), (3) patients with uncomplicated Escherichia coli O157:H7 HC (n = 14), and (4) children with O157:H7-associated hemolytic uremic syndrome (HUS) (n = 24). Children with uncomplicated E coli O157:H7 HC and HUS were matched for duration of enteric prodrome before blood sample collection. We also compared sFas-L and sFas levels among patients with HUS according to severity of renal dysfunction; abnormally increased sFas-L levels were noted in only 4% of the children (n = 3). Abnormally high concentrations of sFas were noted in 9% of the children with HC caused by a non–verotoxin-producing pathogen, 29% of the patients with uncomplicated E coli O157:H7 HC, and 69% of the children with O157:H7-associated HUS. Compared with healthy controls, patients with HUS had twofold greater concentrations of sFas (P < 0.0001). Levels of sFas were not statistically different between 14 patients with uncomplicated O157:H7 HC and 14 children with HUS (8.2 ± 4.7 versus 11.0 ± 4.6 U/mL, respectively; P < 0.07) when matched for time after onset of enteritis (7.0 ± 3.7 versus 7.3 ± 3.8 days, respectively). Greater concentrations of sFas were noted in patients with HUS who developed oligoanuria (n = 10; P < 0.007), required peritoneal dialysis (n = 10; P < 0.007), or had a decreased glomerular filtration rate (n = 5; P < 0.002) 1 year later. Our data show that plasma concentrations of sFas but not sFas-L are abnormally increased in children with O157:H7 infections. Levels of sFas are associated with severity of renal dysfunction during HUS. Further studies are needed to clearly determine the role and origin of circulating sFas among children with infections caused by E coli O157:H7.

Cholelithiasis following Escherichia coli O157:H7-associated hemolytic uremic syndrome.

Sequelae of Escherichia coli O157:H7-associated hemolytic uremic syndrome (HUS) 2-3 years following an outbreak in Washington State have been prospectively studied to identify predictors of adverse sequelae. Logistic regression analysis was used to examine associations between findings in the acute course and long-term renal and gastrointestinal outcomes. Twenty-one percent of patients had gastrointestinal sequelae, which included cholelithiasis resulting in cholecystectomy (3/29), persistent pancreatitis (2/29), late colon stricture (1/29), and/or glucose intolerance (1/29). Logistic regression analysis found long-term gastrointestinal sequelae were higher in patients who, during HUS, had hypertension [odds ratio (OR) = 21.2, 95% confidence interval (CI) = 1.9-164.4, P = 0.01] or gastrointestinal complications (OR = 21.2, 95% CI = 1.9-164.4, P = 0.01). Renal sequelae were seen in 35% of patients. One patient (4%) had persistent hypertension and 9 (31%) had minor urinary findings (hematuria or proteinuria). Thrombocytopenia lasting longer than 10 days during the acute illness was associated with a risk for subsequent renal sequelae (OR = 15.0, 95% CI = 1.98-1,703.0, P = 0.009). We conclude a high incidence of gastrointestinal sequelae, especially cholelithiasis presenting long after the acute illness, may be seen with HUS. The short follow-up period may underestimate the extent and severity of eventual renal sequelae.

The Experience of Treatment for the Patients of Escherichia Coli O157 : H7-associated Hemolytic Uremic Syndrome in Sakai

The Experience of Treatment for the Patients of Escherichia Coli O157 : H7-associated Hemolytic Uremic Syndrome in Sakai

P1 blood group antigen expression and epidemic hemolytic uremic syndrome

P1 blood group positivity has been postulated as a host factor which may provide protection against the development of post-enteropathic hemolytic uremic syndrome (HUS). In this study, blood group status in 20 Inuit survivors of Escherichia coli O157:H7-associated HUS was compared with age- and sex-matched controls from the same community who had experienced uncomplicated diarrheal illness due to the same pathogen. Of 20 HUS survivors, 6 were P1 antigen positive compared with 8 of the 20 controls (P = 0.7). We conclude that P1 antigen positivity was not protective against HUS in this population. Further studies of this condition to clarify the role of host factors in verotoxin-induced endothelial damage are indicated.

E. Coli Hemolytic-Uremic Syndrome

A retrospective analysis of 37 children with Escherichia coli 0157:H7-associated hemolytic-uremic syndrome (HUS) traced to contaminated hamburger meat is reported from the University of Washington, Children’s Hospital, Seattle.

Escherichia coli O157:H7–associated hemolytic-uremic syndrome after ingestion of contaminated hamburgers

We conducted a retrospective analysis of 37 children with Escherichia coli O157:H7-associated hemolytic-uremic syndrome. The infection was traced to contaminated hamburgers at a fast-food restaurant chain. Within 5 days of the first confirmed case, the Washington State Department of Health identified the source and interrupted transmission of infection. Ninety-five percent of the children initially had severe hemorrhagic colitis. Nineteen patients (51%) had significant extrarenal abnormalities, including pancreatitis, colonic necrosis, glucose intolerance, coma, stroke, seizures, myocardial dysfunction, pericardial effusions, adult respiratory disease syndrome, and pleural effusions. Three deaths occurred, each in children with severe multisystem disease. At follow-up two children have significant impairment of renal function (glomerular filtration rate < 80 ml/min/per 1.73 Hm 2); both of these children have a normal serum creatinine concentration. Hemolytic-uremic syndrome is the most common cause of acute renal failure in children, and this experience emphasizes the systemic nature of this disease. Clinicians should anticipate that multisystem involvement may occur in these patients, necessitating acute intervention or chronic follow-up. This outbreak of hemolytic-uremic syndrome also highlights the microbiologic hazards of inadequately prepared food and emphasizes the importance of public health intervention in controllinghHemolytic-uremic syndrome. (J P EDIATR 1994;125:519-26)