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Objective: To study the mechanism leading to elevated semen cytokines in men with spinal cord injury (SCI) and to understand if inflammasome pathways are involved in this process. To investigate inflammasome components and end-product cytokines in semen of SCI and control subjects., Design: Prospective study., Setting: Major university medical center., Patient(s): Men with and without SCI (n = 28 per group)., Intervention(s): None., Main Outcome Measure(s): Seminal plasma concentrations of caspase-1, interleukin (IL) 1β, and IL-18 were quantified by ELISA. Caspase-1 in sperm fractions and apoptosis-associated speck-like protein containing a caspase activation and recruitment domain (ASC) in seminal plasma and sperm fractions were identified by Western blot. Localization of proteins in sperm was accomplished by immunocytochemistry., Result(s): ASC, caspase-1, IL-1β, and IL-18 concentrations were elevated in the seminal plasma of SCI subjects compared with control subjects. ASC and caspase-1 were elevated in sperm cells of SCI subjects. Immunocytochemistry revealed that ASC was located in the acrosome, equatorial segment, and midpiece, and caspase-1 in the midpiece., Conclusion(s): This study provides the first evidence of ASC in human semen and demonstrates the involvement of inflammasome proteins in semen of men with SCI. These findings suggest an immunologic basis for abnormal semen quality in men with SCI., (Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.)

Previous studies have demonstrated that moderate hypothermia reduces histopathological damage and improves behavioral outcome after experimental traumatic brain injury (TBI). Further investigations have clarified the mechanisms underlying the beneficial effects of hypothermia by showing that cooling reduces multiple cell injury cascades. The purpose of this study was to determine whether hypothermia could also enhance endogenous reparative processes following TBI such as neurogenesis and the replacement of lost neurons. Male Sprague-Dawley rats underwent moderate fluid-percussion brain injury and then were randomized into normothermia (37°C) or hypothermia (33°C) treatment. Animals received injections of 5-bromo-2'-deoxyuridine (BrdU) to detect mitotic cells after brain injury. After 3 or 7 days, animals were perfusion-fixed and processed for immunocytochemistry and confocal analysis. Sections were stained for markers selective for cell proliferation (BrdU), neuroblasts and immature neurons (doublecortin), and mature neurons (NeuN) and then analyzed using non-biased stereology to quantify neurogenesis in the dentate gyrus (DG). At 7 days after TBI, both normothermic and hypothermic TBI animals demonstrated a significant increase in the number of BrdU-immunoreactive cells in the DG as compared to sham-operated controls. At 7 days post-injury, hypothermia animals had a greater number of BrdU (ipsilateral cortex) and doublecortin (ipsilateral and contralateral cortex) immunoreactive cells in the DG as compared to normothermia animals. Because adult neurogenesis following injury may be associated with enhanced functional recovery, these data demonstrate that therapeutic hypothermia sustains the increase in neurogenesis induced by TBI and this may be one of the mechanisms by which hypothermia promotes reparative strategies in the injured nervous system., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Experimental and clinical findings demonstrate that traumatic brain injury (TBI) results in injury to both gray and white matter structures. The purpose of this study was to document patterns of oligodendrocyte vulnerability to TBI. Sprague Dawley rats underwent sham operated procedures or moderate fluid percussion brain injury. Quantitative immunohistochemical analysis was performed on animals perfusion-fixed at 3 (n=9) or 7 (n=9) days post-surgery. Within the ipsilateral external capsule and corpus callosum, numbers of APC-CC1 immunoreactive oligodendrocytes were significantly decreased at 3 or 7 days post-TBI compared to sham rats (p<0.03). At both posttraumatic survival periods, double-labeling studies indicated that oligodendrocytes showed increased Caspase 3 activation compared to sham. These data demonstrate regional patterns of oligodendrocyte vulnerability after TBI and that oligodendrocyte cell loss may be due to Caspase 3-mediated cell death mechanisms. Further studies are needed to test therapeutic interventions that prevent trauma-induced oligodendrocyte cell death, subsequent demyelination and circuit dysfunction., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

The purpose of this study was to document patterns of oligodendrocyte vulnerability to TBI and determine whether posttraumatic hypothermia prevents oligodendrocyte cell loss. Sprague Dawley rats underwent moderate fluid percussion brain injury. Thirty minutes after TBI, brain temperature was reduced to 33°C for 4 hrs or maintained at normothermic levels (37°C). Animals were perfusion-fixed for quantitative immunohistochemical analysis at 3 (n=9) or 7 (n=9) days post-TBI. Within the cerebral cortex, external capsule and corpus callosum, numbers of APC-CC1 immunoreactive oligodendrocytes at 3 and 7 days following TBI were significantly decreased compared to sham operated rats (p<0.02). Double-labeling studies showed that vulnerable oligodendrocytes expressed increased Caspase 3 activation compared to sham. Posttraumatic hypothermia significantly reduced the number of CC1 positive oligodendrocytes lost after normothermia TBI in white matter tracts (p<0.01). This model of TBI leads to quantifiable regional patterns of oligodendrocyte vulnerability. Posttraumatic hypothermia protects oligodendrocytes by interfering with Caspase 3-mediated cell death mechanisms. Therapeutic hypothermia may improve functional outcome by attenuating trauma-induced oligodendrocyte cell death, subsequent demyelination and circuit dysfunction.

The purpose of this study was to investigate the effects of an induced period of post-traumatic epilepsy (PTE) on the histopathological damage caused by traumatic brain injury (TBI). Male Sprague Dawley rats were given a moderate parasagittal fluid-percussion brain injury (1.9-2.1 atm) or sham surgery. At 2 weeks after surgery, seizures were induced by administration of a GABA(A) receptor antagonist, pentylenetetrazole (PTZ, 30 mg/kg). Seizures were then assessed over a 1-h period using the Racine clinical rating scale. To evaluate whether TBI-induced pathology was exacerbated by the seizures, contusion volume and cortical and hippocampal CA3 neuronal cell loss were measured 3 days after seizures. Nearly all TBI rats showed clinical signs of PTE following the decrease in inhibitory activity. In contrast, clinically evident seizures were not observed in TBI rats given saline or sham-operated rats given PTZ. Contusions in TBI-PTZ-treated rats were significantly increased compared to the TBI-saline-treated group (p < 0.001). In addition, the TBI-PTZ rats showed less NeuN-immunoreactive cells within the ipsilateral parietal cerebral cortex (p < 0.05) and there was a trend for decreased hippocampal CA3 neurons in TBI-PTZ rats compared with TBI-saline or sham-operated rats. These results demonstrate that an induced period of post-traumatic seizures significantly exacerbates the structural damage caused by TBI. These findings emphasize the need to control seizures after TBI to limit even further damage to the injured brain.

Traumatic brain injury (TBI) is a major risk factor for the subsequent development of epilepsy. Currently, chronic seizures after brain injury are often poorly controlled by available antiepileptic drugs. Hypothermia treatment, a modest reduction in brain temperature, reduces inflammation, activates pro-survival signaling pathways, and improves cognitive outcome after TBI. Given the well-known effect of therapeutic hypothermia to ameliorate pathological changes in the brain after TBI, we hypothesized that hypothermia therapy may attenuate the development of post-traumatic epilepsy and some of the pathomechanisms that underlie seizure formation. To test this hypothesis, adult male Sprague Dawley rats received moderate parasagittal fluid-percussion brain injury, and were then maintained at normothermic or moderate hypothermic temperatures for 4 h. At 12 weeks after recovery, seizure susceptibility was assessed by challenging the animals with pentylenetetrazole, a GABA(A) receptor antagonist. Pentylenetetrazole elicited a significant increase in seizure frequency in TBI normothermic animals as compared with sham surgery animals and this was significantly reduced in TBI hypothermic animals. Early hypothermia treatment did not rescue chronic dentate hilar neuronal loss nor did it improve loss of doublecortin-labeled cells in the dentate gyrus post-seizures. However, mossy fiber sprouting was significantly attenuated by hypothermia therapy. These findings demonstrate that reductions in seizure susceptibility after TBI are improved with post-traumatic hypothermia and provide a new therapeutic avenue for the treatment of post-traumatic epilepsy., (© 2010 The Authors. European Journal of Neuroscience © 2010 Federation of European Neuroscience Societies and Blackwell Publishing Ltd.)

Sex influences histological and behavioral outcomes following traumatic brain injury (TBI), but the underlying sex-dependent pathomechanisms regulating outcome measures remain poorly defined. Here, we investigated the TBI-induced regulation of the X-linked inhibitor of apoptosis protein (XIAP) that, in addition to suppressing cell death by inhibition of caspases, is involved in signaling cascades, including immune regulation and cell migration. Since estrogen has been shown to have anti-apoptotic properties, we specifically examined sex differences and the influence of estrogen on XIAP processing after TBI. Sprague-Dawley male (TBI-M), female (TBI-F), ovariectomized female (TBI-OVX) and ovariectomized females supplemented with estrogen (TBI-OVX+EST) were subjected to moderate (1.7-2.2atm) fluid percussion (FP) injury. Animals were sacrificed 24h after FP injury; cortical tissue (ipsilateral and contralateral) was dissected and analyzed for XIAP processing by immunoblot analysis (n=6-7/group) or confocal microscopy (n=2-3/group). Significant differences in XIAP cleavage products in the ipsilateral cortex were found between groups (p<0.03). Post hoc analysis showed an increase in XIAP processing in both TBI-F and TBI-OVX+EST compared to TBI-M and TBI-OVX (p<0.05), indicating that more XIAP is cleaved following injury in intact females and TBI-OVX+EST than in TBI-M and TBI-OVX groups. Co-localization of XIAP within neurons also demonstrated sex-dependent changes. Based on these data, it appears that the processing of XIAP after injury is different between males and females and may be influenced by exogenous estrogen treatment.

Traumatic brain injury elicits acute inflammation that in turn exacerbates primary brain damage. A crucial part of innate immunity in the immune privileged central nervous system involves production of proinflammatory cytokines mediated by inflammasome signaling. Here, we show that the nucleotide-binding, leucine-rich repeat pyrin domain containing protein 1 (NLRP1) inflammasome consisting of NLRP1, caspase-1, caspase-11, apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), the X-linked inhibitor of apoptosis protein, and pannexin 1 is expressed in neurons of the cerebral cortex. Moderate parasagittal fluid-percussion injury (FPI) induced processing of interleukin-1beta, activation of caspase-1, cleavage of X-linked inhibitor of apoptosis protein, and promoted assembly of the NLRP1 inflammasome complex. Anti-ASC neutralizing antibodies administered immediately after fluid-percussion injury to injured rats reduced caspase-1 activation, X-linked inhibitor of apoptosis protein cleavage, and processing of interleukin-1beta, resulting in a significant decrease in contusion volume. These studies show that the NLRP1 inflammasome constitutes an important component of the innate central nervous system inflammatory response after traumatic brain injury and may be a novel therapeutic target for reducing the damaging effects of posttraumatic brain inflammation.

We investigated the temporal and regional profile of blood-brain barrier (BBB) permeability to both large and small molecules after moderate fluid percussion (FP) brain injury in rats and determined the effects of post-traumatic modest hypothermia (33 degrees C/4 h) on these vascular perturbations. The visible tracers biotin-dextrin-amine 3000 (BDA-3K, 3 kDa) and horseradish peroxidase (HRP, 44 kDa) were injected intravenously at 4 h or 3 or 7 days post-TBI. At 30 min after the tracer infusion, both small and large molecular weight tracers were detected in the contusion area as well as remote regions adjacent to the injury epicenter in both cortical and hippocampal structures. In areas adjacent to the contusion site, increased permeability to the small molecular weight tracer (BDA-3K) was evident at 4 h post-TBI and remained visible after 7 days survival. In contrast, the larger tracer molecule (HRP) appeared in these remote areas at acute permeable sites but was not detected at later post-traumatic time periods. A regionally specific relationship was documented at 3 days between the late-occurring permeability changes observed with BDA-3K and the accumulation of CD68-positive macrophages. Mild hypothermia initiated 30 min after TBI reduced permeability to both large and small tracers and the infiltration of CD68-positive cells. These results indicate that moderate brain injury produces temperature-sensitive acute, as well as more long-lasting vascular perturbations associated with secondary injury mechanisms.

Inflammation is a major contributor to the pathogenesis of cerebral ischemia and stroke. In the peripheral immune response, caspase-1 activation involves the formation of a macromolecular complex termed the inflammasome. We determined whether nucleotide-binding, leucine-rich repeat, pyrin domain containing 1 (NLRP1), molecular platform consisting of capase-1, apoptosis-associated speck-like protein containing a caspase-activating recruitment domain (ASC), and NLRP1, is expressed in the normal and postischemic brain. Mice underwent thromboembolic stroke to investigate the formation of the inflammasome and subsequent activation of downstream inflammatory responses. Western blot analysis showed expression and activation of interleukin (IL) IL-1beta and IL-18 at 24 h after stroke. Size-exclusion chromatography and coimmunoprecipitation analysis showed protein association between NLRP1, ASC, caspase-1, and the X-linked inhibitor of apoptosis protein (XIAP). After ischemia, immunohistochemical analysis revealed inflammasome proteins in neurons, astrocytes, and microglia/macrophages. The potential of the inflammasome as an antiinflammatory target was showed by interference of inflammasome activation resulting in reduced cytokine levels in mice treated after ischemia with a neutralizing antibody against NLRP1. These findings show that the inflammasome complex forms after focal brain ischemia and may be a novel therapeutic target for reducing the detrimental consequences of postischemic inflammation.

The early inflammatory response to traumatic brain injury (TBI) may result in secondary damage. The purpose of this study was to evaluate the effects of a transient treatment employing a blocking monoclonal antibody (mAb) to the CD11d/CD18 integrin on histopathological outcome and macrophage infiltration following TBI. A parasagittal fluid percussion (FP) brain injury (1.8-2.1 atm) was induced in male Sprague-Dawley rats. Rats were randomized into two trauma groups, treated (N=7) and nontreated (N=8) animals. In the treated group, a mAb to the CD11d subunit of the CD11d/CD18 integrin was administered 30 min, 24 and 48 h after brain injury. Control animals received an isotype-matched irrelevant mAb using the same dose and treatment regimen. At 3 days after TBI, animals were perfusion-fixed for histopathological and immunocytochemical analysis. The anti-CD11d mAb treatment reduced contusion areas as well as overall contusion volume compared to vehicle treated animals. For example, overall contusion volume was reduced from 2.7+/-0.5 mm(3) (mean+/-SEM) to 1.4+/-0.4 with treatment (p<0.05). Immunocytochemical studies identifying CD68 immunoreactive macrophages showed that treatment caused significant attenuation of leukocyte infiltration into the contused cortical areas. These data emphasize the beneficial effects of blocking inflammatory cell recruitment into the injured brain on histopathological outcome following traumatic brain injury.

The Fas/CD95 receptor-ligand system plays an essential role in apoptosis that contributes to secondary damage after spinal cord injury (SCI), but the mechanism regulating the efficiency of FasL/Fas signaling in the central nervous system (CNS) is unknown. Here, FasL/Fas signaling complexes in membrane rafts were investigated in the spinal cord of adult female Fischer rats subjected to moderate cervical SCI and sham operation controls. In sham-operated animals, a portion of FasL, but not Fas was present in membrane rafts. SCI resulted in FasL and Fas translocation into membrane raft microdomains where Fas associates with the adaptor proteins Fas-associated death domain (FADD), caspase-8, cellular FLIP long form (cFLIPL ), and caspase-3, forming a death-inducing signaling complex (DISC). Moreover, SCI induced expression of Fas in clusters around the nucleus in both neurons and astrocytes. The formation of the DISC signaling platform leads to rapid activation of initiator caspase-8 and effector caspase-3, and the modification of signaling intermediates such as FADD and cFLIP(L) . Thus, FasL/Fas-mediated signaling after SCI is similar to Fas expressing Type I cell apoptosis.

Tumor necrosis factor (TNF) plays a critical role in pathomechanisms associated with secondary damage after traumatic brain injury (TBI). The TNF ligand-receptor system stimulates inflammation by activation of gene transcription through the IkappaB kinase (IKK)-NF-kappaB and c-Jun NH(2)-terminal kinase (JNK)-AP-1 signaling cascades. TNF signaling following TBI involves both cell survival and apoptotic pathways, but the mechanism that accounts for the dual role of TNF remains unclear. Multiple studies have reported hypothermia to be protective following TBI, but the precise mechanism has not been clearly defined. Here, TNFR1 signaling pathways were investigated in the cerebral cortex of adult male Sprague-Dawley rats subjected to moderate fluid-percussion TBI and of naïve controls. Another group was subjected to moderate TBI with 30 min of pre- and post-traumatic hypothermia (33 degrees C). Rapid and marked increases in protein expression of TNFR1 and signaling intermediates in both the IKK-NF-kappaB and JNK pathways were induced in traumatized cortices. Hypothermia decreased TNFR1 protein expression acutely in traumatized cortices and stimulated early activation of signaling intermediates in the JNK, but not the IKK-NF-kappaB, signaling pathways. Hypothermia promoted a rapid activation of caspase-3 acutely after injury but suppressed caspase-3 activation at later time points. Moreover, hypothermia treatment suppressed cleavage of X-linked inhibitor of apoptosis protein (XIAP) into fragments induced by TBI. These data suggest that hypothermia may regulate both the JNK signaling cascade via XIAP and the preconditioning pathways that activate caspases. Thus, hypothermia mediates TNFR1 responses via early activation of the JNK signaling pathway and caspase-3, leading to endogenous neuroprotective events.

XIAP is a member of the inhibitor of apoptosis (IAP) gene family that, in addition to suppressing cell death by inhibition and polyubiquitination of caspases, is involved in an increasing number of signaling cascades. Moreover, the function and regulation of XIAP in the central nervous system (CNS) is poorly understood. In this study, the authors investigated the cell-type expression, the subcellular distribution, ubiquitination of XIAP, and levels of Smac/DIABLO in the normal adult rat brain and in brains subjected to moderate traumatic brain injury (TBI). In the normal brain, XIAP was predominantly expressed in the perinuclear region of neurons. Traumatized brains showed dramatic alterations in cellular and regional expression of XIAP early after injury. Stereologic analyses of the number of XIAP-positive cells within the hippocampus of both hemispheres showed a biphasic response. Immunoprecipitation and immunoblots of extracts derived from different brain regions demonstrated that a single ubiquitin modifies XIAP. Normal cortex contained significantly higher levels of monoubiquitinated XIAP than hippocampus. TBI induced alterations in levels of monoubiquitinated XIAP that correlated with changes in XIAP distribution and immunoreactivity, suggesting that monoubiquitination of XIAP may be a regulator of XIAP location or activity. Similar levels of Smac/DIABLO were present in lysates of normal and traumatized brains. These data demonstrate for the first time a region-specific regulation of XIAP monoubiquitination in the normal adult rat brain, and after TBI, that may be a key event in the regulation of XIAP function contributing to the pathogenesis following injury.

The inhibitor of apoptosis (IAP) gene family prevents cell death by binding to and inhibiting caspases. In addition to negatively regulating apoptosis, IAPs bind to signaling intermediates and receptors, and participate in diverse cellular functions. Here, we describe the physiological functions of IAPs and their participation in injury and disease processes.

Background: A number of studies have provided evidence that apoptosis is a central element in the regulation of hair follicle regression. In androgenetic alopecia (AGA), the exact location and control of key players in the apoptotic pathways remains obscure., Objective: In the present study, we used a panel of antibodies and investigated the spatial and cellular pattern of expression of caspases and inhibitors of apoptosis (IAPs), such as XIAP and FLIP, in men with normal scalp and in men with AGA before and after 6 months of treatment with 1 mg oral finasteride treatment., Methods and Results: Constitutive expression of caspases-1, -3, -8, and -9 and XIAP was detected predominantly within the isthmic and infundibular hair follicle area, basilar layer of the epidermis, and eccrine and sebaceous glands. AGA-affected tissues showed an increase in caspase (-1, -3, -6, -9) immunoreactivity with a concomitant decrease in XIAP staining. After 6 months of finasteride treatment, both caspases and XIAP were similar to levels exhibited by normal subjects. Immunoblot analysis was performed to determine antibody specificity and cellular expression of caspases. Purified populations of keratinocytes, melanocytes, dermal papilla, and dermal fibroblasts derived from human hair follicles were cultured in vitro and treated with 0.5 mm staurosporin. Time-course experiments revealed that processing of caspase-3 is a principal event during apoptosis of these hair cell types., Conclusion: These data suggest that alterations in levels of caspases and IAPs regulate hair follicle homeostasis. Moreover, finasteride appears to influence caspase and XIAP expression in hair follicle cells thus signaling anagen, active growth in the hair cycle.

The aim of this study was to determine whether hypoxic-ischemia from asphyxial cardiac arrest activates brain caspases-1 and -3, and the anti-apoptotic protein, XIAP. Asphyxial cardiac arrest in rats was used to induce hypoxic-ischemia. A pan-caspase inhibitor (zVAD) was given in the treatment group. At 72 h after reperfusion, caspase-3 and XIAP expression were present in multiple vulnerable brain regions, whereas caspase-1 was predominantly found in the CA1 hippocampus. zVAD significantly reduced expression of caspases and XIAP and the number of ischemic neurons in the CA1 hippocampus while neurological deficit scores were improved. We conclude that hypoxic-ischemia increases caspases-1 and-3, and XIAP expression. Treatment with zVAD significantly decreases caspase and XIAP expression in these brain regions and improves neurological outcome.

Caspase and inhibitor of apoptosis (IAP) expression was examined in rats subjected to moderate traumatic brain injury (TBI) using a parasagittal fluid-percussion brain insult (1.7 to 2.2 atm). Within 1 hour after injury, caspase-8 and -9, two initiators of apoptosis, were predominantly expressed in superficial cortical areas adjacent to the impact site and in the thalamus. Caspase-3, an effector caspase, was evident at 6 hours throughout the traumatized cerebral cortex and hippocampus. Moreover, the authors observed that XIAP, cIAP-1, and cIAP-2, members of the IAP family, were constitutively expressed in the brain. Colocalization of XIAP-immunolabled cells with cell-specific markers indicated that XIAP is expressed within neurons and a subpopulation of oligodendrocytes. Immunoblots of brain extracts revealed that the processed forms of caspase-8, -9, and -3 are present as early as 1 hour after trauma. The appearance of activated caspases corresponded with the detection of cleavage of XIAP into fragments after injury and a concomitant increase in the levels of cIAP-1 and cIAP-2 in the traumatized hemispheres. The current data are consistent with the hypotheses that caspases in both the extrinsic and intrinsic apoptotic pathways are activated after moderate TBI and that IAPs may have a protective role within the brain with alterations in levels and cleavage of IAPs that contribute to cell death in this setting.

A number of studies have provided evidence that cell death from moderate traumatic spinal cord injury (SCI) is regulated, in part, by apoptosis that involves the caspase family of cysteine proteases. However, little or no information is available about anti-apoptotic mechanisms mediated by the inhibitors of apoptosis (IAP) family of proteins that inhibit cell death pathways. In the present study, we examined caspase and IAP expression in spinal cords of rats subjected to moderate traumatic injury. Within 6 h after injury, caspase-8 and-9 (2 initiators of apoptosis) were predominantly present in gray matter neurons within the lesion epicenter. By 3 days following spinal cord injury (SCI), caspase-8 and-9 immunoreactivity was localized to gray and white matter cells, and by 7 days following SCI, both upstream caspases were expressed in cells within white matter or within foamy macrophages in gray matter. Caspase-3, an effector caspase, was evident in a few fragmented cells in gray matter at 24 h following injury and then localized to white matter in later stages. Thus, distinct patterns of caspase expression can be found in the spinal cord following injury. XIAP, cIAP-1, and cIAP-2, members of the IAP family, were constitutively expressed in the cord. Immunoblots of spinal cord extracts revealed that the processed forms of caspases-8 and-9 and cleavage of PARP are present as early as 6 h following trauma. The expression of caspases corresponded with the detection of cleavage of XIAP into 2 fragments following injury. cIAP-1 and cIAP-2 expression remained constant during early periods following SCI but demonstrated alterations by 7 days following SCI. Our data are consistent with the idea that XIAP may have a protective role within the spinal cord, and that alteration in cleavage of XIAP may regulate cell death following SCI.