The Fibrinolytic System in the Hemolytic Uremic Syndrome: In Vivo and In Vitro Studies

To examine whether enhanced in vivo proteolysis of von Willebrand factor (vWF) would account for the reported loss of larger multimers in acute thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), we studied eight patients with acute TTP/HUS whose blood samples were collected into an anticoagulant containing a cocktail of protease inhibitors to impede in vitro proteolysis. In all, enhanced proteolytic degradation of vWF was expressed as a relative decrease in the intact 225-Kd subunit of vWF and a relative increase in the 176-Kd fragment. However, instead of the loss of larger forms of normal multimers reported by other investigators, the plasma of all but one of our patients (whether they had TTP or HUS) contained a set of larger than normal (supranormal) multimers. Hence, although proteolytic fragmentation of vWF was enhanced during acute TTP/HUS, this phenomenon was not associated with the loss of larger multimers. In the five patients who survived the acute disease and underwent plasma exchange (three with HUS and two with chronic relapsing TTP), subunits and fragments returned to normal values, and supranormal multimers were no longer detected in plasma. In conclusion, even though vWF proteolysis is enhanced in acute TTP/HUS, it does not lead to loss of larger multimers.

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Apoptosis of Renal Cortical Cells in the Hemolytic-Uremic Syndrome: In Vivo and In Vitro Studies

Infection and Immunity ◽

10.1128/iai.66.2.636-644.1998 ◽

1998 ◽

Vol 66 (2) ◽

pp. 636-644 ◽

Cited By ~ 116

Author(s):

Diana Karpman ◽

Anders Håkansson ◽

Maria-Thereza R. Perez ◽

Christina Isaksson ◽

Eric Carlemalm ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Dna Fragmentation ◽

Tissue Injury ◽

Apoptotic Cell ◽

Cortical Cells ◽

Necrosis Factor Alpha ◽

E Coli ◽

Uremic Syndrome

ABSTRACT This study examined apoptotic cell death associated with Shiga-like toxin (Stx)-producing Escherichia coli. Renal cortices from three children with postenteropathic hemolytic-uremic syndrome (HUS) and from mice infected with E. coli O157:H7 and pediatric renal tubular epithelial cells stimulated with Stx and E. coli O157:H7 extracts were examined for apoptotic changes. Apoptotic cells were detected by terminal dUTP nick end labeling of tubuli and glomeruli from HUS patients and from mice inoculated with Stx-2-positive and Stx-negative strains. Apoptosis was more extensive and severe ultramorphological nuclear and cytoplasmic changes were seen in the Stx-2-positive group. Stx caused DNA fragmentation and ultramorphological changes indicating apoptosis in cultured pediatric tubular cells. DNA fragmentation increased when cells were prestimulated with tumor necrosis factor alpha. Polymyxin extracts from Stx-2-positive and Stx-negative strains induced DNA fragmentation, but only extracts from Stx-2-positive strains caused ultramorphological changes and extensive DNA fragmentation. The results indicate that HUS is accompanied by increased apoptosis of kidney cells and that bacterial factors, possibly together with host cytokines in vivo, may activate apoptotic tissue injury.

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Enhanced proteolysis of plasma von Willebrand factor in thrombotic thrombocytopenic purpura and the hemolytic uremic syndrome

Blood ◽

10.1182/blood.v74.3.978.978 ◽

1989 ◽

Vol 74 (3) ◽

pp. 978-983 ◽

Cited By ~ 5

Author(s):

PM Mannucci ◽

R Lombardi ◽

A Lattuada ◽

P Ruggenenti ◽

GL Vigano ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Thrombotic Thrombocytopenic Purpura ◽

Von Willebrand Factor ◽

Relative Increase ◽

Thrombocytopenic Purpura ◽

Uremic Syndrome ◽

Von Willebrand ◽

Willebrand Factor

Abstract To examine whether enhanced in vivo proteolysis of von Willebrand factor (vWF) would account for the reported loss of larger multimers in acute thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), we studied eight patients with acute TTP/HUS whose blood samples were collected into an anticoagulant containing a cocktail of protease inhibitors to impede in vitro proteolysis. In all, enhanced proteolytic degradation of vWF was expressed as a relative decrease in the intact 225-Kd subunit of vWF and a relative increase in the 176-Kd fragment. However, instead of the loss of larger forms of normal multimers reported by other investigators, the plasma of all but one of our patients (whether they had TTP or HUS) contained a set of larger than normal (supranormal) multimers. Hence, although proteolytic fragmentation of vWF was enhanced during acute TTP/HUS, this phenomenon was not associated with the loss of larger multimers. In the five patients who survived the acute disease and underwent plasma exchange (three with HUS and two with chronic relapsing TTP), subunits and fragments returned to normal values, and supranormal multimers were no longer detected in plasma. In conclusion, even though vWF proteolysis is enhanced in acute TTP/HUS, it does not lead to loss of larger multimers.

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Development of DNA Vaccines against Hemolytic-Uremic Syndrome in a Murine Model

Infection and Immunity ◽

10.1128/iai.71.7.3971-3978.2003 ◽

2003 ◽

Vol 71 (7) ◽

pp. 3971-3978 ◽

Cited By ~ 20

Author(s):

Alejandra V. E. Capozzo ◽

Virginia Pistone Creydt ◽

Graciela Dran ◽

Gabriela Fernández ◽

Sonia Gómez ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Humoral Response ◽

Host Cells ◽

Newborn Mice ◽

B Subunit ◽

Adult Mice ◽

Uremic Syndrome ◽

A Subunit

ABSTRACT Shiga toxin type 2 (Stx2) produced by Escherichia coli O:157H7 can cause hemolytic-uremic syndrome in children, a disease for which there is neither a vaccine nor an effective treatment. This toxin consists of an enzymatically active A subunit and a pentameric B subunit responsible for the toxin binding to host cells, and also found to be immunogenic in rabbits. In this study we developed eukaryotic plasmids expressing the B subunit gene of Stx2 (pStx2B) and the B subunit plus the gene coding for the A subunit with an active-site deletion (pStx2ΔA). Transfection of eukaryotic cells with these plasmids produced proteins of the expected molecular weight which reacted with specific monoclonal antibodies. Newborn and adult BALB/c mice immunized with two intramuscular injections of each plasmid, either alone or together with the same vector expressing the granulocyte and monocyte colony-stimulating factor (pGM-CSF), elicited a specific Th1-biased humoral response. The effect of pGM-CSF as an adjuvant plasmid was particularly notable in newborn mice and in pStx2B-vaccinated adult mice. Stx2-neutralizing activity, evaluated in vitro on VERO cell monolayers, correlated with in vivo protection. This is the first report using plasmids to induce a neutralizing humoral immune response against the Stx2.

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Activation of the Nlrp3 Inflammasome Contributes to Shiga Toxin-Induced Hemolytic Uremic Syndrome in a Mouse Model

Frontiers in Immunology ◽

10.3389/fimmu.2020.619096 ◽

2021 ◽

Vol 11 ◽

Author(s):

Liqiong Song ◽

Yuchun Xiao ◽

Xianping Li ◽

Yuanming Huang ◽

Guangxun Meng ◽

...

Keyword(s):

Hemolytic Uremic Syndrome ◽

Nlrp3 Inflammasome ◽

Gene Knockout ◽

Peritoneal Macrophages ◽

Inflammasome Activation ◽

Nlrp3 Inflammasome Activation ◽

Uremic Syndrome ◽

Biochemical Indices

ObjectiveTo explore the role of the Nlrp3 inflammasome activation in the development of hemolytic uremic syndrome (HUS) induced by Stx2 and evaluate the efficacy of small molecule Nlrp3 inhibitors in preventing the HUS.MethodsPeritoneal macrophages (PMs) isolated from wild-type (WT) C57BL/6J mice and gene knockout mice (Nlrc4-/-, Aim2-/-, and Nlrp3-/-) were treated with Stx2 in vitro and their IL-1β releases were measured. WT mice and Nlrp3-/- mice were also treated with Stx2 in vivo by injection, and the biochemical indices (serum IL-1β, creatinine [CRE] and blood urea nitrogen [BUN]), renal injury, and animal survival were compared. To evaluate the effect of the Nlrp3 inhibitors in preventing HUS, WT mice were pretreated with different Nlrp3 inhibitors (MCC950, CY-09, Oridonin) before Stx2 treatment, and their biochemical indices and survival were compared with the WT mice without inhibitor pretreatment.ResultsWhen PMs were stimulated by Stx2 in vitro, IL-1β release in Nlrp3-/- PMs was significantly lower compared to the other PMs. The Nlrp3-/- mice treated by Stx2 in vivo, showed lower levels of the biochemical indices, alleviated renal injuries, and increased survival rate. When the WT mice were pretreated with the Nlrp3 inhibitors, both the biochemical indices and survival were significantly improved compared to those without inhibitor pretreatment, with Oridonin being most potent.ConclusionNlrp3 inflammasome activation plays a vital role in the HUS development when mice are challenged by Stx2, and Oridonin is effective in preventing HUS.

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Abnormal Sensitivity of Cortisol-Producing Adrenocortical Adenomas to Serotonin: In Vivo and in Vitro Studies

Yearbook of Endocrinology ◽

10.1016/s0084-3741(08)70169-0 ◽

2007 ◽

Vol 2007 ◽

pp. 358-361

Author(s):

D.E. Schteingart

Keyword(s):

In Vitro Studies ◽

Adrenocortical Adenomas

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The Venom of the Boomslang (Dispholidus Typus): In Vivo and in Vitro Studies

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653532 ◽

1969 ◽

Vol 21 (02) ◽

pp. 234-244 ◽

Cited By ~ 5

Author(s):

N Mackay ◽

J.C Ferguson ◽

Antonia Bagshawe ◽

A.T.T Forrester ◽

G.P Mcnicol

Keyword(s):

In Vitro Studies

SummaryAn account is given of the effects of boomslang venom in man. Evidence was found of a fibrinolytic state apparently secondary to the coagulant action of the venom. These features rapidly responded to the administration of specific antivenom. In vitro studies, using a homogenate of boomslang parotids, confirmed the coagulant properties of the venom and showed them to be of much greater potency than the proteolytic actions.

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