OC 70.1 - High molecular kininogen cleavage in cerebral malaria

Wednesday, June 28, 2023

10:15 – 10:30 ET

Room: 516

Session Available As: Live-Stream and On-Demand

Presenting Author(s)

Alessandro Pinheiro, PhD (he/him/his)

Postdoctoral
Division of Hematology and Oncology Department of Medicine Case Western Reserve University
Cleveland, Ohio, United States

Co-Author(s)

Sadiq Silbak, BS, MS

Pre-doctoral student
Department of Pathology, Case Western Reserve University
Cleveland, Ohio, United States
AM

Alona Merkulova

Research Assistant
Division of Hematology and Oncology Department of Medicine Case Western Reserve University
Cleveland, Ohio, United States
YS

Yelenna Skomorovska-Prokvolit

Reserch Associate
Centre for Global Health and Diseases, Case Western Reserve University
Cleveland, Ohio, United States
KM

Keith R. McCrae

Director. Benign Hematology, Taussig Cancer Institute
Cleveland Clinic Foundation, Cleveland, OH, USA
Clevelend, Ohio, United States
DM

David Midem

Clinical officer
Chulaimbo Sub-county Hospital
Kisumu County, Western, Kenya
SO

Sidney Ogolla

Research scientist
Kenya Medical Research Institute
kisumu, Western, Kenya
AD

Arlene Dent

Associate Professor
Department of Pediatrics, Centre for Global Health and Diseases, Case Western Reserve University
Cleveland, Ohio, United States
AP

Ana Acacia Pinheiro

Professor
Instituto de Biofisica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro
Rio de Janeiro, Rio de Janeiro, Brazil
JK

James Kazura

Professor
Centre for Global Health and Diseases, Case Western Reserve University
Cleveland, Ohio, United States
AS

Alvin Schmaier

Professor
Division of Hematology and Oncology Department of Medicine Case Western Reserve University
Cleveland, Ohio, United States

Background: Cerebral malaria (CM) due to Plasmodium falciparum infection is a major cause of death in African children. CM manifests with coma and brain swelling due to vasogenic edema.

Aims: To investigate whether high molecular weight kininogen (HK) cleavage mediates CM.

Methods: Plasma HK levels in Kenyan children with CM and “uncomplicated” malaria (UM) were measured by immunoblot and competitive ELISA. Plasma CM biomarkers were analyzed by Luminex Multiplex Assay. P. berghei ANKA [PbA, experimental cerebral malaria (ECM)] iRBCs infected C57BL/6 mice were examined for parasitemia and neurologic changes (SHIRPA protocol). Evans blue dye uptake quantified brain edema. Murine plasmas were studied for aPTT, PT, and HK activity.

Results: Immunoblot of human plasma showed 56 and 46 kDa cHK in 42% (8/19) of CM vs 17% (3/18) UM patients. HK levels of CM, as measured by CELISA patients at hospital admission (59 ± 4.1 μg/ml; mean ± SEM, n=23), were significantly lower (p < 0.001) than at discharge (70 ± 3.6 μg/ml; p< 0.0001) and compared to healthy children. Low HK levels significantly correlated (Spearman) positively with uPA, TFPI and negatively with VWF, Syndecan-4, IL-6, TNF, and IL-21 (p < 0.01). In ECM, Day 5 PbA-infected mice had prolonged aPTTs, PTs, and reduced plasma HK levels. PbA-infected Kng1-/- (HK KO) mice were protected significantly from neurologic deterioration vs WT mice (p=0.0063) and had a 58% reduction in brain edema (p=0.0006). PbA-infected Klkb1-/- (PK KO) mice also were protected from neurologic deterioration (p=0.003) and had 64% reduction (p < 0.0001) in brain edema. In contrast, PbA-infected F12-/- (FXII KO) mice only had a 33% reduction in brain edema (p=0.019) and no protection from neurologic deterioration.

Conclusion(s): These data indicate that cHK may be a marker for CM. Plasma HK and PK significantly influence vasogenic edema and neurologic integrity of ECM [Grant support NIH AI130131, HL157405, HL143402, HL144113].

Learning Objectives:

Upon completion, participant will be able to identify HK levels variation in plasma samples from patients with cerebral and uncomplicated malaria (CM and UM).
Upon completion, participant will be able to evaluate if the contact system proteins are involved in edema formation by Evans Blue uptake in the experimental cerebral malaria mice model.
Upon completion, participant will be able to analyze the contact system involvement in cerebral malaria disease.