An integrin inhibiting molecule decreases oxidative damage and improves neurological function after spinal cord injury
ABSTRACT Our previous studies have shown that treatment with an alpha4beta1 integrin blocking antibody after spinal cord injury (SCI) in rats decreases intraspinal inflammation and oxidative damage, improving neurological function. Here, we studied effects of a high affinity small molecule alpha4beta1 inhibitor, BIO5192. First, rats were treated intravenously with BIO5192 (10 mg/kg) or with vehicle (controls) to assess effects of integrin blockade for 24 h or 72 h after thoracic clip-compression SCI. BIO5192 treatment significantly decreased the MPO enzymatic activity (neutrophil infiltration) and ED-1 expression (macrophage density) by 40% and 38% at 24 h and by 52% and 25% at 72 h post injury, respectively. In cord homogenates, BIO5192 treatment decreased expression of the oxidative enzymes gp91(phox), inducible nitric oxide and cyclooxygenase-2 by approximately 40% at both times of analysis. Free radical concentration decreased by 30% and lipid peroxidation decreased by 34% and 46%, respectively, at 24 h and 72 h after SCI. Next, after blockade by BIO5192 for 72 h, neurological outcomes were analyzed for 1-6 weeks after SCI. Motor function significantly improved when assessed by an open-field test. Treated rats planter placed their hind paws and/or dorsal stepped, with weight support, whereas controls only swept their hindlimbs. BIO5192 treatment also decreased mechanical allodynia elicited from the trunk and hind paw by up to 35%. This improved function correlated with decreased lesion size and spared myelin-containing white matter. The neurological improvement offered by this neuroprotective strategy supports the potential for an anti-integrin treatment for SCI.
- SourceAvailable from: Ching-Yi Lin
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- "important. The CS-1 fragment is much smaller than full-length fibronectin, which suggests that CS-1: (1) more easily diffuses away from the injected sites to exert its effects, (2) is more biologically stable because of fewer digestive sites for proteases , (3) is less likely to produce side effects because of the lack of binding sites for interaction, and (4) is more specific because the CS-1 fragment binds specifically to integrin a4b1, which is present on multiple cell types, including endothelium (Hamill 1987; Milner and Campbell, 2002), inflammatory cells (Bao et al., 2008), glia, and neurons (Lefcort et al., 1992; Su et al., 2008; Tomaselli et al., 1993; Werner et al., 2000). It is likely that the combined participation of all of these cell types upon fibronectin stimulation provides a more favorable microenviroment for later functional recovery (Kadoya et al., 2009). "
ABSTRACT: Chronic pain following spinal cord injury (SCI) is a highly prevalent clinical condition that is difficult to treat. Using both von Frey filaments and radiant infrared heat to assess mechanical allodynia and thermal hyperalgesia, respectively, we have demonstrated that a one-time injection of fibronectin (50 μg/mL) into the spinal dorsal column (1 μL/min each injection for a total of 5 μL) immediately after SCI inhibits the development of mechanical allodynia (but not thermal hyperalgesia) over an 8-month observation period following spinal cord dorsal column crush (DCC). DCC will only induce mechanical Allodynia, but not thermal hyperalgesia or overt motor deficits. By applying various fibronectin fragments as well as competitive inhibitors, these effects were shown to be dependent on the connecting segment-1 (CS-1) motif of fibronectin. Furthermore, we found that acute fibronectin treatment diminished inflammation and blood-spinal cord barrier permeability, which in turn leads to enhanced fiber sparing and sprouting. In particular, the reduction of serotonin (5-HT) in the superficial dorsal horn, an important descending brainstem system in the modulation of pain, was blocked with fibronectin treatment. We conclude that treatment of SCI with fibronectin preserves sensory regulation and prevents the development of chronic allodynia, providing a potential therapeutic intervention to treat chronic pain following SCI.Journal of neurotrauma 02/2012; 29(3):589-99. DOI:10.1089/neu.2011.2059 · 3.97 Impact Factor
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- "However, further studies will be needed to address the involvement of specific subtypes of macrophages in the injured cord. A number of studies using antibody blockade (Fleming et al., 2008; Gris et al., 2004; Mabon et al., 2000), and pharmacological (Bao et al., 2008; Noble et al., 2002) and genetic (Letellier et al., 2010) strategies to block the early infiltration of leukocytes, report an improvement in long-term neurological outcomes. In the present study, improved neurological recovery and white matter sparing were limited to those animals that had been depleted of both neutrophils and monocytes. "
ABSTRACT: Strategies that block infiltration of leukocytes into the injured spinal cord improve sparing of white matter and neurological recovery. In this article, we examine the dependency of recovery on hematogenous depletion of neutrophils and monocytes. Mice were depleted of neutrophils or monocytes by systemic administration of anti-Ly6G or clodronate-liposomes. A third group was depleted of both subsets. Neurological improvement, based on a battery of tests of performance, and white matter sparing, occurred only in animals depleted of both neutrophils and monocytes. We also attempted to define the nature of the environment that was favorable to recovery. Hemeoxygenase-1 and malondialdehyde, markers of oxidative stress and lipid peroxidation, respectively, were reduced to similar levels in animals depleted of both neutrophils and monocytes, or only monocytes, but remained elevated in the group only depleted of neutrophils. Matrix metalloproteinase-9, a protease involved in early damage, was most strongly reduced in animals depleted of both leukocyte subsets. Finally, disruption of the blood-spinal cord barrier and abnormal nonheme iron accumulation were reduced only in animals depleted of both neutrophils and monocytes. Together, these findings indicate cooperation between neutrophils and monocytes in mediating early pathogenesis in the contused spinal cord and defining long-term neurological recovery.Journal of neurotrauma 06/2011; 28(9):1893-907. DOI:10.1089/neu.2011.1860 · 3.97 Impact Factor
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- "Infiltrating inflammatory cells have been significantly correlated with the amount of damaged tissue after injury . These observations have been the basis for the design of different strategies directed towards eliminating immune cells from the injury site  . However, recent findings have suggested that the presence and function of these cells are essential for CNS-tissue protection and regeneration    . "
ABSTRACT: Lipid peroxidation (LP) is one of the most harmful mechanisms developed after spinal cord (SC) injury. Several strategies have been explored in order to control this phenomenon. Protective autoimmunity is a physiological process based on the modulation of inflammatory cells that can be boosted by immunizing with neural-derived peptides, such as A91. Since inflammatory cells are among the main contributors to lipid peroxidation, we hypothesized that protective autoimmunity could reduce LP after SC injury. In order to test this hypothesis, we designed two experiments in SC contused rats. First, animals were immunized with a neural-derived peptide seven days before injury. With the aim of inducing the functional elimination of CNS-specific T cells, for the second experiment, animals were tolerized against SC-protein extract and thereafter subjected to a SC injury. The lipid-soluble fluorescent products were used as an index of lipid peroxidation and were assessed after injury. Immunization with neural-derived peptides reduced lipid peroxidation after SC injury. Functional elimination of CNS-specific T cells avoided the beneficial effect induced by protective autoimmunity. The present study demonstrates the beneficial effect of immunizing with neural-derived peptides on lipid peroxidation inhibition; besides this, it also provides evidence on the neuroprotective mechanisms exerted by protective autoimmunity.Neuroscience Letters 04/2010; 476(2):62-5. DOI:10.1016/j.neulet.2010.04.003 · 2.06 Impact Factor