Aprotinin, but not ε-aminocaproic acid and tranexamic acid, exerts neuroprotection against excitotoxic injury in an in vitro neuronal cell culture model.
OBJECTIVE
Lack of availability of aprotinin has resulted in increased clinical use of the alternative antifibrinolytic agents, ε-aminocaproic acid (EACA) and tranexamic acid (TXA), which are known to be associated with an increased risk of seizures. In contrast, aprotinin has previously been demonstrated to be neuroprotective through suppression of excitotoxicity-mediated neuronal degeneration via the extracellular plasminogen/plasmin system. This study compares the effect of antifibrinolytic agents on neuronal and mixed glial/neuronal cell cultures.


METHODS
Mixed cortical cultures containing neuronal and glial cells were prepared from fetal mice and plated on a layer of confluent astrocytes from postnatal pups. A primary neuronal culture was obtained from the same gestational stage and plated in multiwall vessels. Slowly triggered excitotoxicity was induced by 24-hour exposure to 12.5 mM N-methyl-D-aspartate (NMDA). Apoptotic neuronal cell death was induced by exposure of primary neural cultures to 24 hours of serum deprivation.


RESULTS
Compared with NMDA alone, no significant changes in cell death were observed for any dose of TXA or EACA in mixed cultures. Conversely, a clinical dose of aprotinin significantly reduced cell death by -31% on average. Aprotinin reduced apoptotic neuronal cell death from 75% to 37.3%, and to 34.1% at concentrations of 100 and 200 kIU/mL, respectively, and significantly decreased neuronal nuclear damage. These concentrations of aprotinin significantly inhibited caspase 9 and 3/7 activations; 250 kIU/mL aprotinin exerted maximal protection on primary cortical neurons.


CONCLUSIONS
In contrast to aprotinin, EACA and TXA exert no protective effect against excitotoxic neuronal injury that can occur during cardiac surgery.
Children's National Heart Institute, Children's National Medical Center, Washington, DC; Department of Thoracic and Cardiovascular Surgery, Shanghai Children's Medical Center, Shanghai, China.
Zhaohui
Z
Lu
Children's National Heart Institute, Children's National Medical Center, Washington, DC; Center for Neuroscience Research, Children's National Medical Center, Washington, DC.
Ludmila
L
Korotcova
Children's National Heart Institute, Children's National Medical Center, Washington, DC; Center for Neuroscience Research, Children's National Medical Center, Washington, DC.
Akira
A
Murata
Children's National Heart Institute, Children's National Medical Center, Washington, DC; Center for Neuroscience Research, Children's National Medical Center, Washington, DC.
Nobuyuki
N
Ishibashi
Children's National Heart Institute, Children's National Medical Center, Washington, DC; Center for Neuroscience Research, Children's National Medical Center, Washington, DC. Electronic address: rjonas@cnmc.org.
Richard A
RA
Jonas
D015119:Aminocaproic Acid / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D000933:Antifibrinolytic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D007611:Aprotinin / Q000494:pharmacology*; D020169:Caspases / Q000378:metabolism; D002540:Cerebral Cortex / Q000187:drug effects* / Q000196:embryology / Q000378:metabolism / Q000473:pathology; D018920:Coculture Techniques; D019610:Cytoprotection; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D061252:Feeder Cells; D005865:Gestational Age; D051379:Mice; D016202:N-Methylaspartate / Q000633:toxicity*; D009457:Neuroglia / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014148:Tranexamic Acid / Q000494:pharmacology*
D000933:Antifibrinolytic Agents; D018690:Excitatory Amino Acid Agonists; D018696:Neuroprotective Agents; D016202:N-Methylaspartate; D014148:Tranexamic Acid; D007611:Aprotinin; D020169:Caspases; D015119:Aminocaproic Acid