Dataset Information

Enhanced clearance of Abeta in brain by sustaining the plasmin proteolysis cascade.

ABSTRACT: The amyloid hypothesis states that a variety of neurotoxic beta-amyloid (Abeta) species contribute to the pathogenesis of Alzheimer's disease. Accordingly, a key determinant of disease onset and progression is the appropriate balance between Abeta production and clearance. Enzymes responsible for the degradation of Abeta are not well understood, and, thus far, it has not been possible to enhance Abeta catabolism by pharmacological manipulation. We provide evidence that Abeta catabolism is increased after inhibition of plasminogen activator inhibitor-1 (PAI-1) and may constitute a viable therapeutic approach for lowering brain Abeta levels. PAI-1 inhibits the activity of tissue plasminogen activator (tPA), an enzyme that cleaves plasminogen to generate plasmin, a protease that degrades Abeta oligomers and monomers. Because tPA, plasminogen and PAI-1 are expressed in the brain, we tested the hypothesis that inhibitors of PAI-1 will enhance the proteolytic clearance of brain Abeta. Our data demonstrate that PAI-1 inhibitors augment the activity of tPA and plasmin in hippocampus, significantly lower plasma and brain Abeta levels, restore long-term potentiation deficits in hippocampal slices from transgenic Abeta-producing mice, and reverse cognitive deficits in these mice.

SUBMITTER: Jacobsen JS

PROVIDER: S-EPMC2438386 | biostudies-literature | 2008 Jun

REPOSITORIES: biostudies-literature

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Enhanced clearance of Abeta in brain by sustaining the plasmin proteolysis cascade.

Jacobsen J Steven JS Comery Thomas A TA Martone Robert L RL Elokdah Hassan H Crandall David L DL Oganesian Aram A Aschmies Suzan S Kirksey Yolanda Y Gonzales Cathleen C Xu Jane J Zhou Hua H Atchison Kevin K Wagner Erik E Zaleska Margaret M MM Das Indranil I Arias Robert L RL Bard Jonathan J Riddell David D Gardell Stephen J SJ Abou-Gharbia Magid M Robichaud Albert A Magolda Ronald R Vlasuk George P GP Bjornsson Thorir T Reinhart Peter H PH Pangalos Menelas N MN

Proceedings of the National Academy of Sciences of the United States of America 20080616 25

The amyloid hypothesis states that a variety of neurotoxic beta-amyloid (Abeta) species contribute to the pathogenesis of Alzheimer's disease. Accordingly, a key determinant of disease onset and progression is the appropriate balance between Abeta production and clearance. Enzymes responsible for the degradation of Abeta are not well understood, and, thus far, it has not been possible to enhance Abeta catabolism by pharmacological manipulation. We provide evidence that Abeta catabolism is increa ...[more]

PMID: 18559859

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Project description:BackgroundThe purpose of this study was to examine the impact of ARC on levetiracetam concentrations during the first week following acute TBI. The hypothesis was levetiracetam concentrations are significantly lower in TBI patients with augmented renal clearance (ARC) compared to those with normal renal clearance.MethodsThis is a prospective cohort pharmacokinetic study of adults with moderate to severe TBI treated with levetiracetam during the first week after injury. Serial blood collections were performed daily for analysis of levetiracetam, cystatin C, and 12-hr creatinine clearance (CrCl) determinations. Patients were divided into two cohorts: with (CrCl ≥130 ml/min/1.73 m2) and without ARC.ResultsTwenty-two patients with moderate to severe TBI were included. The population consisted primarily of young male patients with severe TBI (mean age 40 years old, 68% male, median admission GCS 4). Each received levetiracetam 1000 mg IV every 12 h for the study period. ARC was present in 77.3% of patients, with significantly lower levetiracetam concentrations in ARC patients and below the conservative therapeutic range (< 6mcg/mL) for all study days. In patients without ARC, the serum concentrations were also below the expected range on all but two study days (Days 4 and 5). Four of the 22 (18.2%) patients exhibited seizure activity during the study period (two of these patients exhibited ARC). Cystatin C concentrations were significantly lower in patients with ARC, though the mean for all patients was within the typical normal range.ConclusionsARC has a high prevalence in patients with moderate to severe TBI. Levetiracetam concentrations after standard dosing were low in all TBI patients, but significantly lower in patients with ARC. This study highlights the need to consider personalized drug dosing in TBI patients irrespective of the presence of ARC.Clinical trial registrationThis study was registered at cliicaltrials.gov (NCT02437838) Registered on 08/05/2015, https://clinicaltrials.gov/ct2/show/NCT02437838 .

Dataset Information

Enhanced clearance of Abeta in brain by sustaining the plasmin proteolysis cascade.

Publications

Enhanced clearance of Abeta in brain by sustaining the plasmin proteolysis cascade.

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