Prostacyclin infusion in haemolytic-uraemic syndrome of children

Shiga Toxin 2a-Induced Endothelial Injury in Hemolytic Uremic Syndrome: A Metabolomic Analysis

BACKGROUND

Endothelial dysfunction plays a pivotal role in the pathogenesis of postenteropathic hemolytic uremic syndrome (HUS), most commonly caused by Shiga toxin (Stx)-producing strains of Escherichia coli.

METHODS

To identify new treatment targets, we performed a metabolomic high-throughput screening to analyze the effect of Stx2a, the major Stx type associated with HUS, on human renal glomerular endothelial cells (HRGEC) and umbilical vein endothelial cells (HUVEC). Cells were treated either with sensitizing tumor necrosis factor α (TNF-α) or Stx2a, a sequence of both or remained untreated.

RESULTS

We identified 341 metabolites by combined liquid chromatography/tandem mass spectrometry and gas chromatography/mass spectrometry. Both cell lines exhibited distinct metabolic reaction profiles but shared elevated levels of free fatty acids. Stx2a predominantly altered the nicotinamide adenine dinucleotide (NAD) cofactor pathway and the inflammation-modulating eicosanoid pathway, which are associated with lipid metabolism. In HRGEC, Stx2a strongly diminished NAD derivatives, leading to depletion of the energy substrate acetyl coenzyme A and the antioxidant glutathione. HUVEC responded to TNF-α and Stx2a by increasing production of the counteracting eicosanoids prostaglandin I2, E1, E2, and A2, while in HRGEC only more prostaglandin I2 was detected.

CONCLUSIONS

We conclude that disruption of energy metabolism and depletion of glutathione contributes to Stx-induced injury of the renal endothelium and that the inflammatory response to Stx is highly cell-type specific.

Successful treatment of hemolytic uremic syndrome and thrombotic thrombocytopenic purpura with fresh frozen plasma and plasma exchange

Four patients with hemolytic uremic syndrome (HUS) and seven with thrombotic thrombocytopenic purpura (TTP) were treated with infusions of fresh frozen plasma (FFP). In one patient with HUS and five patients with TTP this treatment was combined with plasma exchange (PE). The additional treatment varied; corticosteroids, antiplatelet drugs, heparin and blood exchange. All but one patient recovered completely in spite of severe illness with uremia, oliguria and/or cerebral symptoms during the acute phase. The results were surprisingly good in comparison with other published series. The success must in the first place be attributed to early diagnosis and to the infusions of FFP. PE seemed to potentiate the effect of FFP.

Prostacyclin counteracts the increase in capillary permeability induced by tumour necrosis factor-alpha

OBJECTIVE

To analyse how prostacyclin interferes with the short-term local circulatory effects of tumour necrosis factor-alpha (TNF alpha) in a skeletal muscle.

DESIGN

An autoperfused sympathectomised cat gastrocnemius muscle enclosed in a plethysmograph.

INTERVENTIONS

Arterial blood flow, total and segmental vascular resistances (large-bore arterial vessels, arterioles and veins), hydrostatic capillary pressure, tissue volume and capillary filtration coefficient were followed during local intra-arterial infusion of TNF alpha at various rates (2.5, 5.0 and 7.5 micrograms/kg per min) and during intra-arterial infusion of prostacyclin simultaneously with the highest dose of TNF alpha. The capillary filtration coefficient reflects the capillary surface for fluid exchange.

RESULTS

Arterial infusion of TNFx had no influence on vascular resistance up to 5.0 micrograms/kg per min but induced vasodilation at 7.5 micrograms/kg per min. No effects on the recorded hydrostatic capillary pressure were observed. The capillary filtration coefficient and the capillary filtration increased with the infusion rate of TNF alpha, the former by 55%. Simultaneous arterial infusion of prostacyclin (350 ng/kg per min) caused further vasodilation and an increase in hydrostatic capillary pressure and completely restored the capillary filtration coefficient to control. The TNF alpha-induced filtration was partly restored.

CONCLUSIONS

The local circulatory effect of TNF alpha is small apart from a graded increase in the capillary filtration coefficient, most likely reflecting an increase in the capillary permeability. The prostacyclin-induced decrease in capillary filtration coefficient most likely reflects a restoration of capillary permeability. The TNF alpha-induced transcapillary filtration is not fully reduced by prostacyclin due to a simultaneous increase in hydrostatic capillary pressure.

Partial clinical improvement in Upshaw-Schulman syndrome following prostacyclin infusion

We report on a Japanese girl with Upshaw-Schulman syndrome, a congenital disorder characterized by recurrent thrombocytopenia, microangiopathic hemolytic anemia, proteinuria and hematuria that can be transiently improved by the transfusion of plasma or various plasma components. Unusually Large von Willebrand Factor (ULvWF) multimers were found during both relapse and remission phases. Serial plasma levels of 6-keto-prostaglandin F1 alpha (PGF1 alpha), the stable metabolite of prostacyclin (PGI2), were low at relapse. When the patient was treated with continuous PGI2 infusion, the microangiopathic hemolytic process gradually subsided within 10 days. These results suggest that PGI2 may be partly involved in the pathogenesis of this congenital disorder.

Prostacyclin in diarrhoea-associated haemolytic uraemic syndrome

The role of prostacyclin (PGI2) in the pathogenesis of haemolytic uraemic syndrome (HUS) is controversial. In part, confusion has been caused by failure to distinguish between two main sub-types of the syndrome: extrinsic, diarrhoea-associated HUS (D+ HUS), usually caused by infection with verocytotoxin-producing Escherichia coli or Shigella dysenteriae, and the heterogeneous group of non-prodromal forms where intrinsic factors predominate (D- HUS). This paper critically reviews data confined to D+ HUS. Two methods have been used to assess PGI2 synthesis; the generation of PGI2 from endothelium in the presence of HUS plasma in vitro and the measurement of stable metabolites in body fluids. No concensus could be reached with regard to the former. The reported increase of PGI2 stable metabolites in plasma may represent reduced clearance or increased carriage by plasma lipids. Apparent differences between studies of urinary excretion of PGI2 metabolites may reflect the way excretion was expressed. If the metabolite concentration is factored for urinary creatinine, it appears that renal excretion and thus renal synthesis of PGI2 is reduced. However, these are insufficient data on which to attribute the pathogenesis of D+ HUS to disordered PGI2 metabolism.

Prostacyclin concentrations in haemolytic uraemic syndrome after acute shigellosis in children

The role of prostacyclin in the pathogenesis of haemolytic uraemic syndrome was evaluated in 11 children with acute shigellosis. Plasma concentrations of 6-keto prostaglandin, F1 alpha, a stable metabolite of prostacyclin, were measured by radioimmunoassay during acute illness, early convalescence, and after clinical recovery. Its concentration was low during acute illness in each patient, returning to normal concentrations or above at the time of the last sample. These results suggest that plasma prostacyclin may be involved in the development of the syndrome.

Absence of plasma prostacyclin stimulating activity deficiency in hemolytic uremic syndrome

We compared the effect of plasma from 19 children with hemolytic uremic syndrome (HUS) on prostacyclin (PGI2) production by fresh rat aortic rings to the effect of plasma from 17 age- and sex-matched normal children, taking into account the PGI2 baseline aortic production (PGI2 release in presence of buffer, 21 determinations). After 10, 20, 30, 40, and 60 minutes incubation of rat aortic tissue with either plasma or buffer, the presence of PGI2 was studied by measuring by radioimmunoassay (RIA) the concentration of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha). 6-keto-PGF1 alpha production increased with time in the two groups of plasma samples and in the presence of buffer, but 6-keto-PGF1 alpha production (ng/mg dried tissue) after 30 minutes incubation and mean 6-keto-PGF1 alpha production (slope of regression line, ng/mg/min) were significantly (P less than 0.01) lower in the presence of normal plasma compared with buffer, and significantly (P less than 0.01) higher in the presence of HUS plasma compared with normal plasma. There was no significant difference between buffer and HUS plasma. We conclude that, under our experimental conditions, normal plasma had an inhibitory activity on 6-keto-PGF1 alpha production by rat aorta. This inhibitory activity was absent in HUS plasma.

Hemolytic-uremic syndrome: an analysis of the natural history and prognostic features

Sixty-seven children with hemolytic-uremic syndrome (HUS) were admitted between 1974 and 1981. Of these, 52 (78%) were aged less than 3 years. All children had acute renal failure and 48 (72%) required peritoneal dialysis. The etiology in twenty cases varied from bacterial and viral infections (7 and 5 cases, respectively) to renal irradiation with chemotherapy (2) and preexisting glomerulopathy (1). 5 (7%) children died during the acute phase of the illness. Long-term follow-up (mean 3 years 3 months) of 56 cases showed that 37 children (60%) had so far experienced no functional sequelae and 8 (13%) only mild sequelae while 3 (5%) were on iterative hemodialysis, 3 had severe chronic renal failure and high blood pressure (HBP) and 5 (8%) had HBP and normal kidney function. While the recovery rate was approximately 60% in all age groups, the mortality rate and serious after-effects were twice as frequent (42%) in children over 3 years of age as in those less than 3. Renal histology (total of 37) showed 12 cases of cortical necrosis, 22 of glomerular thrombotic microangiopathy (TMA) and 3 arterial TMA. Prognosis was poor for all cases of arterial TMA and 58% of those exhibiting cortical necrosis.

The effects of intravenous ZK36-374, a stable prostacyclin analogue, on normal volunteers

Prostacyclin (PGI2) therapy has been evaluated in many vascular diseases. However, it is unstable and a potent vasodilator, able to lower blood pressure. Although such effects may be desirable in some situations, they are unwanted in others. ZK36-374 (Schering AG) is a carbacyclin derivative with a similar action to PGI2; however, it is chemically stable and has less of a hypotensive action. We evaluated the effects of a 4-hour I.V. infusion of ZK36-374 at a maximum dose of 2ng/Kg/min. in ten normal volunteers. Prior to the infusion and at 2 and 4 hours, blood was sampled for estimation of platelet aggregation in both platelet rich plasma and whole blood. Beta-thromboglobulin, 6-keto-PGF1 alpha and TXB2 were measured by radioimmunoassay, as were other coagulation and rheological tests. The infusion was well tolerated with facial flushing, jaw trismus and some nausea at max dose. Blood pressure and pulse rate were not significantly altered. During infusion of ZK36-374, the rates of platelet aggregation to 2 microns ADP and 2 micrograms collagen in PRP were significantly decreased when compared to baseline, as was whole blood aggregation to 2 microns ADP and 0.5 microgram collagen. Beta TG also fell significantly, as did the levels of 6-keto-PGF1 alpha and TXB2. Fibrinolysis, blood viscosity, and red cell deformability were unchanged. ZK36-374 is an effective anti-platelet agent without major toxic or hypotensive effects.

Adult hemolytic-uremic syndrome: successful treatment with plasmapheresis

Two adult patients with the hemolytic-uremic syndrome were treated successfully with intense plasma exchange. One patient had recurrent episodes and, with each relapse, both their thrombocytopenia and acute renal failure were reversed with plasma exchange therapy alone. These cases demonstrate the useful role of plasma exchange in the therapy of severe idiopathic hemolytic-uremic syndrome in adults.

Plasmapheresis as a therapeutic measure in hemolytic-uremic syndrome in children

Three children with hemolytic-uremic syndrome (HUS) were successfully treated with plasmapheresis (HUS) were successfully treated with plasmapheresis (PP) combined with early hemodialysis and administration of Aspirin and dipyridamole. Stimulation of vascular prostacyclin release with patients' plasma was measured before and after PP. It was reduced before and increased after plasma exchange. The data indicate that PP might be a useful tool in treatment of (HUS) in children.

Side effects occurring during administration of epoprostenol (prostacyclin, PGI2), in man

1 Fifty infusions of epoprostenol (PGI2) were made, usually increasing the infusion rate until adverse effects were encountered. The volunteers were appraised that they might experience headache and facial flushing. 2 Facial flushing, headache, tachycardia and decrease in diastolic blood pressure were seen in almost all subjects. Erythema over the venous infusing site was also encountered in 13 infusions. Less common effects were sudden bradycardia, pallor and sweating--the vagal reflex--(seven times) and chest pain (twice). Other complaints included restlessness, abdominal discomfort, nausea and drowsiness. 3 The literature on side effects reported during PGI2 infusion is reviewed and recommendations are made concerning administration of PGI2.