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Studies of selective TNF inhibitors in the treatment of brain injury from stroke and trauma: a review of the evidence to date.

Tuttolomondo A, Pecoraro R, Pinto A - Drug Des Devel Ther (2014)

Bottom Line: TNF-α increases the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor density on the cell surface and simultaneously decreases expression of γ-aminobutyric acid receptor cells, and these effects are related to a direct neurotoxic effect.Etanercept, a biologic TNF antagonist, has a reported effect of decreasing microglia activation in experimental models, and it has been used therapeutically in animal models of ischemic and traumatic neuronal damage.On this basis, it appears that etanercept may improve outcomes of TBI by penetrating into the cerebrospinal fluid in rats, although further studies in humans are needed to confirm these interesting and suggestive experimental findings.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Department of Internal and Specialistic Medicine, University of Palermo, Palermo, Italy.

ABSTRACT
The brain is very actively involved in immune-inflammatory processes, and the response to several trigger factors such as trauma, hemorrhage, or ischemia causes the release of active inflammatory substances such as cytokines, which are the basis of second-level damage. During brain ischemia and after brain trauma, the intrinsic inflammatory mechanisms of the brain, as well as those of the blood, are mediated by leukocytes that communicate with each other through cytokines. A neuroinflammatory cascade has been reported to be activated after a traumatic brain injury (TBI) and this cascade is due to the release of pro- and anti-inflammatory cytokines and chemokines. Microglia are the first sources of this inflammatory cascade in the brain setting. Also in an ischemic stroke setting, an important mediator of this inflammatory reaction is tumor necrosis factor (TNF)-α, which seems to be involved in every phase of stroke-related neuronal damage such as inflammatory and prothrombotic events. TNF-α has been shown to have an important role within the central nervous system; its properties include activation of microglia and astrocytes, influence on blood-brain barrier permeability, and influences on glutamatergic transmission and synaptic plasticity. TNF-α increases the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor density on the cell surface and simultaneously decreases expression of γ-aminobutyric acid receptor cells, and these effects are related to a direct neurotoxic effect. Several endogenous mechanisms regulate TNF-α activity during inflammatory responses. Endogenous inhibitors of TNF include prostaglandins, cyclic adenosine monophosphate, and glucocorticoids. Etanercept, a biologic TNF antagonist, has a reported effect of decreasing microglia activation in experimental models, and it has been used therapeutically in animal models of ischemic and traumatic neuronal damage. In some studies using animal models, researchers have reported a limitation of TBI-induced cerebral ischemia due to etanercept action, amelioration of brain contusion signs, as well as motor and cognitive dysfunction. On this basis, it appears that etanercept may improve outcomes of TBI by penetrating into the cerebrospinal fluid in rats, although further studies in humans are needed to confirm these interesting and suggestive experimental findings.

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Common inflammatory pathways involved in neuronal damage after TBI and ischemic stroke.Abbreviations: Alpha-Syn, alpha-synuclein; ATP, adenosine triphosphate; BBB, blood–brain barrier; BDNF, brain-derived neurotrophic factor; CSF-1, colony-stimulating factor 1; GM-CSF, granulocyte-macrophage colony-stimulating factor; HAP1, Huntingtin-associated protein 1; HD, Huntington’s disease; IFN, interferon; IL, interleukin; MMP, matrix metalloproteinase; mHtt, mutant Huntingtin protein; NGF, nerve growth factor; PD, Parkinson’s disease; ROS, reactive oxygen species; TBI, traumatic brain injury; TGF, tumor growth factor; Th, T-helper; TK-r, receptor tyrosine kinases; TNF, tumor necrosis factor; TRkB, neurotrophic tyrosine kinase receptor, type 2; VEGF, vascular endothelial growth factor.
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f1-dddt-8-2221: Common inflammatory pathways involved in neuronal damage after TBI and ischemic stroke.Abbreviations: Alpha-Syn, alpha-synuclein; ATP, adenosine triphosphate; BBB, blood–brain barrier; BDNF, brain-derived neurotrophic factor; CSF-1, colony-stimulating factor 1; GM-CSF, granulocyte-macrophage colony-stimulating factor; HAP1, Huntingtin-associated protein 1; HD, Huntington’s disease; IFN, interferon; IL, interleukin; MMP, matrix metalloproteinase; mHtt, mutant Huntingtin protein; NGF, nerve growth factor; PD, Parkinson’s disease; ROS, reactive oxygen species; TBI, traumatic brain injury; TGF, tumor growth factor; Th, T-helper; TK-r, receptor tyrosine kinases; TNF, tumor necrosis factor; TRkB, neurotrophic tyrosine kinase receptor, type 2; VEGF, vascular endothelial growth factor.

Mentions: A higher degree of expression of adhesion molecules in astrocytes enhances a migration process of inflammatory cells, and it represents one of the possible pathogenic bases of inflammatory-mediated ischemic neuronal damage. ICAM-1 and VCAM-1 have been reported as highly expressed in cultured microglial cells after treatment with TNF-α.16 A high degree of expression of ICAM-1, VCAM-1, and E-selectin has also been shown in cultured endothelial cells from brain vessels after exposure to inflammatory stimuli such as TNF-α17 (Figure 1).


Studies of selective TNF inhibitors in the treatment of brain injury from stroke and trauma: a review of the evidence to date.

Tuttolomondo A, Pecoraro R, Pinto A - Drug Des Devel Ther (2014)

Common inflammatory pathways involved in neuronal damage after TBI and ischemic stroke.Abbreviations: Alpha-Syn, alpha-synuclein; ATP, adenosine triphosphate; BBB, blood–brain barrier; BDNF, brain-derived neurotrophic factor; CSF-1, colony-stimulating factor 1; GM-CSF, granulocyte-macrophage colony-stimulating factor; HAP1, Huntingtin-associated protein 1; HD, Huntington’s disease; IFN, interferon; IL, interleukin; MMP, matrix metalloproteinase; mHtt, mutant Huntingtin protein; NGF, nerve growth factor; PD, Parkinson’s disease; ROS, reactive oxygen species; TBI, traumatic brain injury; TGF, tumor growth factor; Th, T-helper; TK-r, receptor tyrosine kinases; TNF, tumor necrosis factor; TRkB, neurotrophic tyrosine kinase receptor, type 2; VEGF, vascular endothelial growth factor.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4232043&req=5

f1-dddt-8-2221: Common inflammatory pathways involved in neuronal damage after TBI and ischemic stroke.Abbreviations: Alpha-Syn, alpha-synuclein; ATP, adenosine triphosphate; BBB, blood–brain barrier; BDNF, brain-derived neurotrophic factor; CSF-1, colony-stimulating factor 1; GM-CSF, granulocyte-macrophage colony-stimulating factor; HAP1, Huntingtin-associated protein 1; HD, Huntington’s disease; IFN, interferon; IL, interleukin; MMP, matrix metalloproteinase; mHtt, mutant Huntingtin protein; NGF, nerve growth factor; PD, Parkinson’s disease; ROS, reactive oxygen species; TBI, traumatic brain injury; TGF, tumor growth factor; Th, T-helper; TK-r, receptor tyrosine kinases; TNF, tumor necrosis factor; TRkB, neurotrophic tyrosine kinase receptor, type 2; VEGF, vascular endothelial growth factor.
Mentions: A higher degree of expression of adhesion molecules in astrocytes enhances a migration process of inflammatory cells, and it represents one of the possible pathogenic bases of inflammatory-mediated ischemic neuronal damage. ICAM-1 and VCAM-1 have been reported as highly expressed in cultured microglial cells after treatment with TNF-α.16 A high degree of expression of ICAM-1, VCAM-1, and E-selectin has also been shown in cultured endothelial cells from brain vessels after exposure to inflammatory stimuli such as TNF-α17 (Figure 1).

Bottom Line: TNF-α increases the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor density on the cell surface and simultaneously decreases expression of γ-aminobutyric acid receptor cells, and these effects are related to a direct neurotoxic effect.Etanercept, a biologic TNF antagonist, has a reported effect of decreasing microglia activation in experimental models, and it has been used therapeutically in animal models of ischemic and traumatic neuronal damage.On this basis, it appears that etanercept may improve outcomes of TBI by penetrating into the cerebrospinal fluid in rats, although further studies in humans are needed to confirm these interesting and suggestive experimental findings.

View Article: PubMed Central - PubMed

Affiliation: Biomedical Department of Internal and Specialistic Medicine, University of Palermo, Palermo, Italy.

ABSTRACT
The brain is very actively involved in immune-inflammatory processes, and the response to several trigger factors such as trauma, hemorrhage, or ischemia causes the release of active inflammatory substances such as cytokines, which are the basis of second-level damage. During brain ischemia and after brain trauma, the intrinsic inflammatory mechanisms of the brain, as well as those of the blood, are mediated by leukocytes that communicate with each other through cytokines. A neuroinflammatory cascade has been reported to be activated after a traumatic brain injury (TBI) and this cascade is due to the release of pro- and anti-inflammatory cytokines and chemokines. Microglia are the first sources of this inflammatory cascade in the brain setting. Also in an ischemic stroke setting, an important mediator of this inflammatory reaction is tumor necrosis factor (TNF)-α, which seems to be involved in every phase of stroke-related neuronal damage such as inflammatory and prothrombotic events. TNF-α has been shown to have an important role within the central nervous system; its properties include activation of microglia and astrocytes, influence on blood-brain barrier permeability, and influences on glutamatergic transmission and synaptic plasticity. TNF-α increases the amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor density on the cell surface and simultaneously decreases expression of γ-aminobutyric acid receptor cells, and these effects are related to a direct neurotoxic effect. Several endogenous mechanisms regulate TNF-α activity during inflammatory responses. Endogenous inhibitors of TNF include prostaglandins, cyclic adenosine monophosphate, and glucocorticoids. Etanercept, a biologic TNF antagonist, has a reported effect of decreasing microglia activation in experimental models, and it has been used therapeutically in animal models of ischemic and traumatic neuronal damage. In some studies using animal models, researchers have reported a limitation of TBI-induced cerebral ischemia due to etanercept action, amelioration of brain contusion signs, as well as motor and cognitive dysfunction. On this basis, it appears that etanercept may improve outcomes of TBI by penetrating into the cerebrospinal fluid in rats, although further studies in humans are needed to confirm these interesting and suggestive experimental findings.

Show MeSH
Related in: MedlinePlus