Bryostatin improves survival and reduces ischemic brain injury in aged rats after acute ischemic stroke.

BACKGROUND AND PURPOSE: Bryostatin, a potent protein kinase C (PKC) activator, has demonstrated therapeutic efficacy in preclinical models of associative memory, Alzheimer disease, global ischemia, and traumatic brain injury. In this study, we tested the hypothesis that administration of bryostatin provides a therapeutic benefit in reducing brain injury and improving stroke outcome using a clinically relevant model of cerebral ischemia with tissue plasminogen activator reperfusion in aged rats. METHODS: Acute cerebral ischemia was produced by reversible occlusion of the right middle cerebral artery (MCAO) in 18- to 20-month-old female Sprague-Dawley rats using an autologous blood clot with tissue plasminogen activator-mediated reperfusion. Bryostatin was administered at 6 hours post-MCAO, then at 3, 6, 9, 12, 15, and 18 days after MCAO. Functional assessment was conducted at 2, 7, 14, and 21 days after MCAO. Lesion volume and hemispheric swelling/atrophy were performed at 2, 7, and 21 days post-MCAO. Histological assessment of PKC isozymes was performed at 24 hours post-MCAO. RESULTS: Bryostatin-treated rats showed improved survival post-MCAO, especially during the first 4 days. Repeated administration of bryostatin post-MCAO resulted in reduced infarct volume, hemispheric swelling/atrophy, and improved neurological function at 21 days post-MCAO. Changes in αPKC expression and εPKC expression in neurons were noted in bryostatin-treated rats at 24 hours post-MCAO. CONCLUSIONS: Repeated bryostatin administration post-MCAO protected the brain from severe neurological injury post-MCAO. Bryostatin treatment improved survival rate, reduced lesion volume, salvaged tissue in infarcted hemisphere by reducing necrosis and peri-infarct astrogliosis, and improved functional outcome after MCAO.

Peri-Hilar Cystic Lymphangioma Mimicking a Biliary Cystic Lesion Causing Biliary Obstruction: A Case Report and Literature Review.

BACKGROUND Lymphangiomas are rare and benign malformations of the lymphatic system. The presentation of intra-abdominal lymphangiomas, especially from within the hepatoduodenal ligament, is rare in the adult population. In this report, we examine a lymphangioma within the hepatoduodenal ligament resulting in biliary obstruction. CASE REPORT A 62-year-old man with surgical history of cholecystectomy presented to the hepatobiliary clinic for a peri-hilar cystic lesion identified on surveillance magnetic resonance imaging (MRI). The patient's MRI revealed a 5.5-cm cystic lesion at the peri-hilar region, likely arising from the biliary tree, which had been increasing in size and causing biliary dilatation. The patient underwent an endoscopic ultrasound, showing a 4.3×2.2 cm cystic structure likley arising from the cystic duct stump with internal septation. An endoscopic retrograde cholangiopancreatography (ERCP) was performed and demonstrated no communication between the biliary tree and the cystic lesion. Given the uncertain etiology of the lesion and its obstructive nature, the patient was moved to the operating room for a complete excision. A well-encapsulated cystic lesion was identified between the cystic duct and the common hepatic duct, which did not communicate with the biliary tree. Pathology confirmed the diagnosis of lymphangioma with features of vascular channel proliferation in the background of fibrotic stroma and lymphoid aggregates. The vascular channel proliferation demonstrated positive immunohistochemical staining for D2-40. At 3-year follow-up, there was no evidence of post-resection recurrence. CONCLUSIONS This case represents an acquired lymphangioma occurring as a sequela of cholecystectomy, likely caused by interruption of the lymphatic drainage system secondary to surgical manipulation.

Traumatic superficial temporal artery pseudoaneurysm & management following mandible fracture.

A traumatic pseudoaneurysm of the superficial temporal artery is a rare vascular lesion that typically occurs after blunt trauma to the temporal region. It accounts for only 1% of all traumatic aneurysms. These pseudoaneurysms need to be appropriately diagnosed and treated without delay as the patient can experience resulting symptoms of severe headache, facial nerve palsy, arterial bleeding, and/or bone erosion. Diagnosis can typically be made with history of trauma along with physical examination followed by confirmation with ultrasound or computer tomography angiogram. The treatment of choice is ligation and resection. We present a case of a 20-year-old male with identified pseudoaneurysm following facial trauma and mandibular fracture repair treated with multiple trials of sclerotherapy. In addition, this report will review additional management options and diagnosis techniques for superficial temporal artery (STA) pseudoaneurysms.

Sarcomatoid Carcinoma of the Ascending Colon: A Case Report and Literature Review.

BACKGROUND Sarcomatoid carcinoma is a rare tumor that can occur in different organs and anatomical locations. Colonic sarcomatoid carcinoma, also known as carcinosarcoma, is an extremely rare tumor, with only 32 cases reported world-wide. The pathogenesis and guidelines for treatment are poorly understood due to the rarity and invasiveness of the disease. CASE REPORT A 77-year-old woman presented with worsening lower abdominal pain and associated fever after having initially been diagnosed with stump appendicitis and associated phlegmon 3 weeks prior, which was treated with antibiotics. Repeat imaging revealed an extraluminal versus perforated colonic mass with associated phlegmon. The patient's condition continued to worsen, with development of obstructive-like symptoms, resulting in operative intervention involving a R2 right hemicolectomy, stapled ileo-colostomy, and partial omentectomy. The patient had an uneventful remainder of her hospitalization other than continued lower abdominal pain. After initial discharge, the patient presented to an outside hospital due to continued deterioration of health, with findings of an additional mass, likely secondary to the previous lymphadenopathy. Ultimately, goals of care were discussed, and the decision was made to provide palliative care, and the patient died due to her illness 32 days after the initial procedure. CONCLUSIONS Carcinosarcoma is an extremely rare tumor with scant research guiding treatment guidelines. Current guidelines gathered from previous case reports suggest treating colorectal carcinosarcoma as adenocarcinoma. Additional research and studies are needed to establish appropriate therapeutic guidelines for carcinosarcoma.

Endovascular repair of aortobronchial fistula three decades after open repair of traumatic aortic transection: A case report and 3-year follow-up.

A rare and lethal vascular condition is the communication of the thoracic aorta and tracheobronchial tree. Typically, the development occurs after open or endovascular aortic repair that has been complicated by infection and usually presents with hemoptysis as the heralding event, which can lead to massive hemorrhage. Computed tomography angiography remains the diagnostic imaging modality of choice. Medical management will be futile, with the need for expedited operative intervention via open, endovascular, or hybrid open and endovascular repair.

Fatal Sequelae of Reperfusion Injury in Postoperative Gastric Bypass.

BACKGROUND Obesity is a pandemic that is currently uncontrolled. In the surgical population, bariatric surgery is a sustainable and attractive option. However, both obesity and surgery can independently increase the risk for venous thromboembolism and subsequent significant and even fatal adverse effects. CASE REPORT We present the unique case of a 63-year-old woman who developed substantial venous thrombosis in the postoperative period following a laparoscopic hiatal hernia repair and Roux-en-Y gastric bypass. Venous thrombosis following surgery is a known possible complication, but we felt that this case required reporting due to the extreme extent of thrombosis and the significant course of events that occurred following her readmission. Due to the increased thrombus burden, the patient developed phlegmasia cerulea dolens and required operative thrombectomy. With restoration of blood flow following the procedure, the patient's clinical status rapidly declined, likely due to reperfusion injury. Ultimately, she developed multisystem organ failure, which included the constellation of shock, hypoxic respiratory failure, acute renal failure, shock liver, and, finally, cardiopulmonary arrest. CONCLUSIONS As the authors of this paper, we were especially inclined to report this particular case as the patient's clinical course was exceedingly complex due to her presenting phlegmasia cerulea dolens. The course was further complicated postoperatively by the detrimental sequelae of massive reperfusion injury, which likely eventually led to her death. We felt this pertinent to present because, after an extensive PubMed literature review, this sequence of events following gastric bypass surgery has yet to be reported in the literature.

Single low-dose lipopolysaccharide preconditioning: neuroprotective against axonal injury and modulates glial cells.

AIM: Over 7 million traumatic brain injuries (TBI) are reported each year in the United States. However, treatments and neuroprotection following TBI are limited because secondary injury cascades are poorly understood. Lipopolysaccharide (LPS) administration before controlled cortical impact can contribute to neuroprotection. However, the underlying mechanisms and whether LPS preconditioning confers neuroprotection against closed-head injuries remains unclear. METHODS: The authors hypothesized that preconditioning with a low dose of LPS (0.2 mg/kg) would regulate glial reactivity and protect against diffuse axonal injury induced by weight drop. LPS was administered 7 days prior to TBI. LPS administration reduced locomotion, which recovered completely by time of injury. RESULTS: LPS preconditioning significantly reduced the post-injury gliosis response near the corpus callosum, possibly by downregulating the oncostatin M receptor. These novel findings demonstrate a protective role of LPS preconditioning against diffuse axonal injury. LPS preconditioning successfully prevented neurodegeneration near the corpus callosum, as measured by fluorojade B. CONCLUSION: Further work is required to elucidate whether LPS preconditioning confers long-term protection against behavioral deficits and to elucidate the biochemical mechanisms responsible for LPS-induced neuroprotective effects.

The role for infarct volume as a surrogate measure of functional outcome following ischemic stroke.

The failed translation of proposed therapeutic agents for ischemic stroke from preclinical to clinical studies has led to increased scrutiny of preclinical studies, namely the model and outcome measures utilized. Preclinical studies routinely use infarct volume as an experimental endpoint or measure in studies employing young-adult, healthy male animals despite the fact that clinically, ischemic stroke is a disease of the elderly and improvements in functional outcome from pre- to post-intervention remains the most widely utilized assessment. The validity of infarct volume as a surrogate measure for functional outcome remains unclear in clinical studies as well as preclinical studies, particularly those utilizing a more clinically relevant aged thromboembolic model. In this work, we will address the relationship between acute and chronic functional outcome and infarct volume using a variety of functional assessments ranging from more simplistic, subjective measurements such as the modified Neurologic Severity Score (mNSS), to more complex, objective measurements such as grip strength and inclined plane.

Amelioration of nicotinamide adenine dinucleotide phosphate-oxidase mediated stress reduces cell death after blast-induced traumatic brain injury.

A total of 1.7 million traumatic brain injuries (TBIs) occur each year in the United States, but available pharmacologic options for the treatment of acute neurotrauma are limited. Oxidative stress is an important secondary mechanism of injury that can lead to neuronal apoptosis and subsequent behavioral changes. Using a clinically relevant and validated rodent blast model, we investigated how nicotinamide adenine dinucleotide phosphate oxidase (Nox) expression and associated oxidative stress contribute to cellular apoptosis after single and repeat blast injuries. Nox4 forms a complex with p22phox after injury, forming free radicals at neuronal membranes. Using immunohistochemical-staining methods, we found a visible increase in Nox4 after single blast injury in Sprague Dawley rats. Interestingly, Nox4 was also increased in postmortem human samples obtained from athletes diagnosed with chronic traumatic encephalopathy. Nox4 activity correlated with an increase in superoxide formation. Alpha-lipoic acid, an oxidative stress inhibitor, prevented the development of superoxide acutely and increased antiapoptotic markers B-cell lymphoma 2 (t = 3.079, P < 0.05) and heme oxygenase 1 (t = 8.169, P < 0.001) after single blast. Subacutely, alpha-lipoic acid treatment reduced proapoptotic markers Bax (t = 4.483, P < 0.05), caspase 12 (t = 6.157, P < 0.001), and caspase 3 (t = 4.573, P < 0.01) after repetitive blast, and reduced tau hyperphosphorylation indicated by decreased CP-13 and paired helical filament staining. Alpha-lipoic acid ameliorated impulsive-like behavior 7 days after repetitive blast injury (t = 3.573, P < 0.05) compared with blast exposed animals without treatment. TBI can cause debilitating symptoms and psychiatric disorders. Oxidative stress is an ideal target for neuropharmacologic intervention, and alpha-lipoic acid warrants further investigation as a therapeutic for prevention of chronic neurodegeneration.

Bryostatin-1 Restores Blood Brain Barrier Integrity following Blast-Induced Traumatic Brain Injury.

Recent wars in Iraq and Afghanistan have accounted for an estimated 270,000 blast exposures among military personnel. Blast traumatic brain injury (TBI) is the 'signature injury' of modern warfare. Blood brain barrier (BBB) disruption following blast TBI can lead to long-term and diffuse neuroinflammation. In this study, we investigate for the first time the role of bryostatin-1, a specific protein kinase C (PKC) modulator, in ameliorating BBB breakdown. Thirty seven Sprague-Dawley rats were used for this study. We utilized a clinically relevant and validated blast model to expose animals to moderate blast exposure. Groups included: control, single blast exposure, and single blast exposure + bryostatin-1. Bryostatin-1 was administered i.p. 2.5 mg/kg after blast exposure. Evan's blue, immunohistochemistry, and western blot analysis were performed to assess injury. Evan's blue binds to albumin and is a marker for BBB disruption. The single blast exposure caused an increase in permeability compared to control (t = 4.808, p < 0.05), and a reduction back toward control levels when bryostatin-1 was administered (t = 5.113, p < 0.01). Three important PKC isozymes, PKCα, PKCδ, and PKCε, were co-localized primarily with endothelial cells but not astrocytes. Bryostatin-1 administration reduced toxic PKCα levels back toward control levels (t = 4.559, p < 0.01) and increased the neuroprotective isozyme PKCε (t = 6.102, p < 0.01). Bryostatin-1 caused a significant increase in the tight junction proteins VE-cadherin, ZO-1, and occludin through modulation of PKC activity. Bryostatin-1 ultimately decreased BBB breakdown potentially due to modulation of PKC isozymes. Future work will examine the role of bryostatin-1 in preventing chronic neurodegeneration following repetitive neurotrauma.

Elucidating the severity of preclinical traumatic brain injury models: a role for functional assessment?

BACKGROUND: Concussion remains a symptom-based diagnosis clinically, yet preclinical studies investigating traumatic brain injury, of which concussion is believed to represent a "mild" form, emphasize histological end points with functional assessments often minimized or ignored all together. Recently, clinical studies have identified the importance of cognitive and neuropsychiatric symptoms, in addition to somatic concerns, following concussion. How these findings may translate to preclinical studies is unclear at present. OBJECTIVE: To address the contrasting end points used clinically compared with those in preclinical studies and the potential role of functional assessments in a commonly used model of diffuse axonal injury (DAI). METHODS: Animals were subjected to DAI by the use of the impact-acceleration model. Functional and behavioral assessments were conducted during 1 week following DAI before the completion of the histological assessment at 1 week post-DAI. RESULTS: We show, despite the suggestion that this model represents concussive injury, no functional impairments as determined by using the common measures of motor, sensorimotor, cognitive, and neuropsychiatric function following injury over the course of 1 week. The lack of functional deficits is in sharp contrast to neuropathological findings indicating neural degeneration, astrocyte reactivity, and microglial activation. CONCLUSION: Future studies are needed to identify functional assessments, neurophysiologic techniques, and imaging assessments more apt to distinguish differences following so-called "mild" traumatic brain injury in preclinical models and determine whether these models are truly studying concussive or subconcussive injury. These studies are needed not only to understand the mechanism of injury and production of subsequent deficits, but also to rigorously evaluate potential therapeutic agents.

SN79, a sigma receptor antagonist, attenuates methamphetamine-induced astrogliosis through a blockade of OSMR/gp130 signaling and STAT3 phosphorylation.

Methamphetamine (METH) exposure results in dopaminergic neurotoxicity in striatal regions of the brain, an effect that has been linked to an increased risk of Parkinson's disease. Various aspects of neuroinflammation, including astrogliosis, are believed to be contributory factors in METH neurotoxicity. METH interacts with sigma receptors at physiologically relevant concentrations and treatment with sigma receptor antagonists has been shown to mitigate METH-induced neurotoxicity in rodent models. Whether these compounds alter the responses of glial cells within the central nervous system to METH however has yet to be determined. Therefore, the purpose of the current study was to determine whether the sigma receptor antagonist, SN79, mitigates METH-induced striatal reactive astrogliosis. Male, Swiss Webster mice treated with a neurotoxic regimen of METH exhibited time-dependent increases in striatal gfap mRNA and concomitant increases in GFAP protein, indicative of astrogliosis. This is the first report that similar to other neurotoxicants that induce astrogliosis through the activation of JAK2/STAT3 signaling by stimulating gp-130-linked cytokine signaling resulting from neuroinflammation, METH treatment also increases astrocytic oncostatin m receptor (OSMR) expression and the phosphorylation of STAT3 (Tyr-705) in vivo. Pretreatment with SN79 blocked METH-induced increases in OSMR, STAT3 phosphorylation and astrocyte activation within the striatum. Additionally, METH treatment resulted in striatal cellular degeneration as measured by Fluoro-Jade B, an effect that was mitigated by SN79. The current study provides evidence that sigma receptor antagonists attenuate METH-induced astrocyte activation through a pathway believed to be shared by various neurotoxicants.

SN79, a sigma receptor ligand, blocks methamphetamine-induced microglial activation and cytokine upregulation.

Methamphetamine (METH) abuse is associated with several negative side effects including neurotoxicity in specific brain regions such as the striatum. The precise molecular mechanisms by which METH usage results in neurotoxicity remain to be fully elucidated, with recent evidence implicating the importance of microglial activation and neuroinflammation in damaged brain regions. METH interacts with sigma receptors which are found in glial cells in addition to neurons. Moreover, sigma receptor antagonists have been shown to block METH-induced neurotoxicity in rodents although the cellular mechanisms underlying their neuroprotection remain unknown. The purpose of the current study was to determine if the prototypic sigma receptor antagonist, SN79, mitigates METH-induced microglial activation and associated increases in cytokine expression in a rodent model of METH-induced neurotoxicity. METH increased striatal mRNA and protein levels of cluster of differentiation 68 (CD68), indicative of microglial activation. METH also increased ionized calcium binding adapter molecule 1 (IBA-1) protein expression, further confirming the activation of microglia. Along with microglial activation, METH increased striatal mRNA expression levels of IL-6 family pro-inflammatory cytokines, leukemia inhibitory factor (lif), oncostatin m (osm), and interleukin-6 (il-6). Pretreatment with SN79 reduced METH-induced increases in CD68 and IBA-1 expression, demonstrating its ability to prevent microglial activation. SN79 also attenuated METH-induced mRNA increases in IL-6 pro-inflammatory cytokine family members. The ability of a sigma receptor antagonist to block METH-induced microglial activation and cytokine production provides a novel mechanism through which the neurotoxic effects of METH may be mitigated.

Modeling clinically relevant blast parameters based on scaling principles produces functional & histological deficits in rats.

Blast-induced traumatic brain injury represents a leading cause of injury in modern warfare with injury pathogenesis poorly understood. Preclinical models of blast injury remain poorly standardized across laboratories and the clinical relevance unclear based upon pulmonary injury scaling laws. Models capable of high peak overpressures and of short duration may better replicate clinical exposure when scaling principles are considered. In this work we demonstrate a tabletop shock tube model capable of high peak overpressures and of short duration. By varying the thickness of the polyester membrane, peak overpressure can be controlled. We used membranes with a thickness of 0.003, 0.005, 0.007, and 0.010 in to generate peak reflected overpressures of 31.47, 50.72, 72.05, and 90.10 PSI, respectively. Blast exposure was shown to decrease total activity and produce neural degeneration as indicated by fluoro-jade B staining. Similarly, blast exposure resulted in increased glial activation as indicated by an increase in the number of glial fibrillary acidic protein expressing astrocytes compared to control within the corpus callosum, the region of greatest apparent injury following blast exposure. Similar findings were observed with regard to activated microglia, some of which displayed phagocytic-like morphology within the corpus callosum following blast exposure, particularly with higher peak overpressures. Furthermore, hematoxylin and eosin staining showed the presence of red blood cells within the parenchyma and red, swollen neurons following blast injury. Exposure to blast with 90.10 PSI peak reflected overpressure resulted in immediate mortality associated with extensive intracranial bleeding. This work demonstrates one of the first examples of blast-induced brain injury in the rodent when exposed to a blast wave scaled from human exposure based on scaling principles derived from pulmonary injury lethality curves.

Effect of slosh mitigation on histologic markers of traumatic brain injury: laboratory investigation.

OBJECT: Helmets successfully prevent most cranial fractures and skull traumas, but traumatic brain injury (TBI) and concussions continue to occur with frightening frequency despite the widespread use of helmets on the athletic field and battlefield. Protection against such injury is needed. The object of this study was to determine if slosh mitigation reduces neural degeneration, gliosis, and neuroinflammation. METHODS: Two groups of 10 adult male Sprague-Dawley rats were subjected to impact-acceleration TBI. One group of animals was fitted with a collar inducing internal jugular vein (IJV) compression prior to injury, whereas the second group received no such collar prior to injury. All rats were killed 7 days postinjury, and the brains were fixed and embedded in paraffin. Tissue sections were processed and stained for markers of neural degeneration (Fluoro-Jade B), gliosis (glial fibrillary acidic protein), and neuroinflammation (ionized calcium binding adapter molecule 1). RESULTS: Compared with the controls, animals that had undergone IJV compression had a 48.7%-59.1% reduction in degenerative neurons, a 36.8%-45.7% decrease in reactive astrocytes, and a 44.1%-65.3% reduction in microglial activation. CONCLUSIONS: The authors concluded that IJV compression, a form of slosh mitigation, markedly reduces markers of neurological injury in a common model of TBI. Based on findings in this and other studies, slosh mitigation may have potential for preventing TBI in the clinical population.

Effects of aging on behavioral assessment performance: implications for clinically relevant models of neurological disease.

OBJECT: Despite the role of aging in development of neurological and neurodegenerative diseases, the effects of age are often disregarded in experimental design of preclinical studies. Functional assessment increases the clinical relevance of animal models of neurological disease and adds value beyond traditional histological measures. However, the relationship between age and functional impairment has not been systematically assessed through a battery of functional tests. METHODS: In this study, various sensorimotor and behavioral tests were used to evaluate effects of aging on functional performance in naive animals. Sensorimotor measures included locomotor activity; Rotarod, inclined plane, and grip-strength testing; and modified Neurological Severity Score. The Morris water maze was used to examine differences in learning and memory, and the elevated plus maze and forced swim test were used to assess anxiety-like and depressive-like behaviors, respectively. RESULTS: Older Sprague-Dawley rats (18-20 months) were found to perform significantly worse on the inclined plane tests, and they exhibited alterations in elevated-plus maze and forced swim test compared with young adult rats (3-4 months). Specifically, older rats exhibited reduced exploration of open arms in elevated plus maze and higher immobility time in forced swim test. Spatial acquisition and reference memory were diminished in older rats compared with those in young adult rats. CONCLUSIONS: This study demonstrates clear differences between naive young adult and older animals, which may have implications in functional assessment for preclinical models of neurological disease.