Glucose but Not Lactate in Combination With Acidosis Aggravates Ischemic Neuronal Death In Vitro

Abstract

Background and Purpose-Hyperglycemia aggravates brain damage in clinical stroke and in experimental in vivo models of cerebral ischemia. Elevated preischemic glucose levels, lactate production, and intracerebral acidosis correlate with increased brain damage. We have developed a murine hippocampal slice culture model of in vitro ischemia (IVI), suitable for studies of the mechanisms of neuronal death. In this model we investigated the individual contribution of glucose, pH, lactate, and combinations thereof as well as ionotropic glutamate receptor activation to the development of hyperglycemic ischemic cell death. Methods-Murine organotypic hippocampal slice cultures were exposed to IVI in a medium with an ionic composition similar to that of the extracellular fluid in the brain during ischemia in vivo. Cell death was assessed by propidium iodide uptake. Ionotropic glutamate receptor blockade was accomplished by D-2-amino-5-phosphonopentanoic acid (D-APV) or 2,3-dihydro-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX

Ischemic Stroke and Glucose Intolerance: a Review of the Evidence and Exploration of Novel Therapeutic Targets

“…Furthermore, hyperglycemia is known to modify many proteins important for cell survival by advanced glycation, inducing some death-related proteins like high mobility group box 1, which triggers the expression of pro-inflammatory mediators, or downregulation of cytoskeletal proteins that support neuronal cell survival (36,37). Interestingly, glucose receptors, known as sodium glucose transporter (SGLT) type 3, may act as glucose-sensing receptors, provoking the Na + -dependent depolarization of the membrane in response to elevated extracellular glucose (38).…”

Management of Hyperglycemia in Acute Stroke

“…In vitro work using murine hippocampal slices has shown that glucose and acidosis are detrimental to cells whereas lactate is not. 64 Using PET scanning it has been shown that lactate may be the preferred energy supply to the brain especially during times of stress. 65 This is relevant to the management of hyperglycemia in acute ischemic stroke patients.…”

Tumor Necrosis Factor Receptor-1 is Essential for LPS-Induced Sensitization and Tolerance to Oxygen—Glucose Deprivation in Murine Neonatal Organotypic Hippocampal Slices

“…An overview of the experimental protocol is given in Figure 1. Before OGD, cultures were washed once in prewarmed phosphate-buffered saline (PBS) and transferred to the anaerobic incubator (Elektrotek Ltd, Keighley, UK) in an empty prewarmed plate according to previously described protocols for OGD (Cronberg et al, 2004). The anaerobic incubator had an atmosphere comprising 10% H 2 , 5% CO 2 , and 85% N 2 , and the temperature was maintained at 35.01C±0.31C.…”

“…Propidium iodide was used as a marker for cell death and was included in the medium in all groups throughout the experimental protocol (Cronberg et al, 2004). Photomicrographs of PI-stained slices were obtained before experimental start and at time points of 4, 12, 24, and 48 h after OGD in all groups.…”