Cerebral microdialysis and glucopenia in traumatic brain injury: A review.

Traditionally, intracranial pressure (ICP) and partial brain tissue oxygenation (PbtO2) have been the primary invasive intracranial measurements used to guide management in patients with severe traumatic brain injury (TBI). After injury however, the brain develops an increased metabolic demand which may require an increment in the oxidative metabolism of glucose. Simultaneously, metabolic, and electrical dysfunction can lead to an inability to meet these demands, even in the absence of ischemia or increased intracranial pressure. Cerebral microdialysis provides the ability to accurately measure local concentrations of various solutes including lactate, pyruvate, glycerol and glucose. Experimental and clinical data demonstrate that such measurements of cellular metabolism can yield critical missing information about a patient's physiologic state and help limit secondary damage. Glucose management in traumatic brain injury is still an unresolved question. As cerebral glucose metabolism may be uncoupled from systemic glucose levels due to the metabolic dysfunction, measurement of cerebral extracellular glucose concentrations could provide more predictive information and prove to be a better biomarker to avoid secondary injury of at-risk brain tissue. Based on data obtained from cerebral microdialysis, specific interventions such as ICP-directed therapy, blood glucose increment, seizure control, and/or brain oxygen optimization can be instituted to minimize or prevent secondary insults. Thus, microdialysis measurements of parenchymal metabolic function provides clinically valuable information that cannot be obtained by other monitoring adjuncts in the standard ICU setting.

Plasma cytokines IL-6, IL-8, and IL-10 are associated with the development of acute respiratory distress syndrome in patients with severe traumatic brain injury.

BACKGROUND: Patients with severe traumatic brain injury (TBI) are at risk of the development of acute respiratory distress syndrome (ARDS). TBI and ARDS pathophysiologic mechanisms are known to independently involve significant inflammatory responses. The literature on the association between plasma inflammatory cytokines and ARDS in patients with TBI is sparse. METHODS: The study was a secondary analysis of the safety of a randomized trial of erythropoietin and transfusion threshold in patients with severe TBI. Inflammatory markers within the first 24 hours after injury were compared in patients who developed ARDS and patients without ARDS, using Cox proportional hazards models. RESULTS: There were 200 patients enrolled in the study. The majority of plasma and cerebrospinal fluid (CSF) cytokine levels were obtained within 6 hours. Plasma proinflammatory markers IL-6 and IL-8 and anti-inflammatory marker IL-10 were associated with the development of ARDS (adjusted hazard ratio (HR) = 1.55, confidence interval (CI) = 1.14, 2.11, P = 0.005 for IL-6; adjusted HR = 1.32, CI = 1.10, 1.59, P = 0.003 for IL-8). CONCLUSION: Plasma markers of IL-6, IL-8, and IL-10 are associated with ARDS in patients with severe TBI. TRIAL REGISTRATION: NCT00313716 registered 4/2006.

Trypanosoma cruzi meningoencephalitis in a patient with acquired immunodeficiency syndrome.

As a result of global migration, a significant number of people with Trypanosoma cruzi infection now live in the United States, Canada, many countries in Europe, and other non-endemic countries. Trypanosoma cruzi meningoencephalitis is a rare cause of ring-enhancing lesions in patients with acquired immunodeficiency syndrome (AIDS) that can closely mimic central nervous system (CNS) toxoplasmosis. We report a case of CNS Chagas reactivation in an AIDS patient successfully treated with benznidazole and antiretroviral therapy in the United States.

The identification and characterization of breast cancer CTCs competent for brain metastasis.

Brain metastatic breast cancer (BMBC) is uniformly fatal and increasing in frequency. Despite its devastating outcome, mechanisms causing BMBC remain largely unknown. The mechanisms that implicate circulating tumor cells (CTCs) in metastatic disease, notably in BMBC, remain elusive. We characterize CTCs isolated from peripheral blood mononuclear cells of patients with breast cancer and also develop CTC lines from three of these patients. In epithelial cell adhesion molecule (EpCAM)-negative CTCs, we identified a potential signature of brain metastasis comprising "brain metastasis selected markers (BMSMs)" HER2+ / EGFR+ / HPSE+ / Notch1+. These CTCs, which are not captured by the CellSearch platform because of their EpCAM negativity, were analyzed for cell invasiveness and metastatic competency in vivo. CTC lines expressing the BMSM signature were highly invasive and capable of generating brain and lung metastases when xenografted in nude mice. Notably, increased brain metastatic capabilities, frequency, and quantitation were detected in EpCAM- CTCs overexpressing the BMSM signature. The presence of proteins of the BMSM CTC signature was also detected in the metastatic lesions of animals. Collectively, we provide evidence of isolation, characterization, and long-term culture of human breast cancer CTCs, leading to the description of a BMSM protein signature that is suggestive of CTC metastatic competency to the brain.

MicroRNA-1258 suppresses breast cancer brain metastasis by targeting heparanase.

Heparanase (HPSE) is a potent protumorigenic, proangiogenic, and prometastatic enzyme that is overexpressed in brain metastatic breast cancer (BMBC). However, little is known about the regulation of this potential therapeutic target in BMBC, which remains very poorly managed in the clinic. We hypothesized that HPSE gene expression might be regulated by micro RNA that might be exploited therapeutically. Using miRanda and RNAhybrid, we identified miR-1258 as a candidate micro RNA that may directly target HPSE and suppress BMBC. In support of our hypothesis, we found that miR-1258 levels inversely correlated with heparanase expression, enzymatic activity, and cancer cell metastatic propensities, being lowest in highly aggressive BMBC cell variants compared with either nontumorigenic or nonmetastatic human mammary epithelial cells. These findings were validated by analyses of miR-1258 and heparanase content in paired clinical specimens of normal mammary gland versus invasive ductal carcinoma, and primary breast cancer versus BMBC. In regulatory experiments, miR-1258 inhibited the expression and activity of heparanase in BMBC cells, whereas modulating heparanase blocked the phenotypic effects of miR-1258. In functional experiments, stable expression of miR-1258 in BMBC cells inhibited heparanase in vitro cell invasion and experimental brain metastasis. Together, our findings illustrate how micro RNA mechanisms are linked to brain metastatic breast cancer through heparanase control, and they offer a strong rationale to develop heparanase-based therapeutics for treatment of cancer patients with brain metastases, BMBC in particular.

Toxoplasmosis myelopathy and myopathy in an AIDS patient: a case of immune reconstitution inflammatory syndrome?

INTRODUCTION: concurrent toxoplasmosis infection of the brain, spinal cord, and muscle has never been reported together in a patient antemortem. Toxoplasma gondii is the most common focal central nervous system opportunistic infection in the acquired immune deficiency syndrome (AIDS) population. Despite this fact, isolated toxoplasmosis infection in the spinal cord is rarely reported. In addition, toxoplasmic myositis is also rarely diagnosed and Toxoplasma cysts are seldom found on biopsy. We present a patient with AIDS and toxoplasmosis resistant to standard anti-Toxoplasma therapy. CASE REPORT: a 34-year-old man with a history of untreated AIDS presented with symptoms of myelopathy. Pathologically proven toxoplasmosis of the spinal cord was diagnosed and no brain lesions were found. However, despite appropriate treatment and initiation of highly active antiretroviral therapy, the patient developed worsening symptoms, including myopathy and autonomic instability. Muscle biopsy revealed Toxoplasma cysts, and there was laboratory evidence of a restored immune system. CONCLUSION: we report the first case of toxoplasmosis presenting initially with myelitis in the absence of encephalitis that subsequently progressed to myositis despite antiparasitic treatment. We also discuss the possibility of immune reconstitution inflammatory syndrome as a cause of his deterioration.

Neurocysticercosis in the HIV era: a case report and review of the literature.

The prevalence of HIV is increasing in countries where neurocysticercosis is endemic. Co-infection rates are expected to rise; however, no systematic reviews of the subject are available. We performed a literature review of neurocysticercosis (NCC) occurring in HIV-infected patients and described the clinical and immunophenotypic characteristics of a NCC case presenting with probable immune reconstitution inflammatory syndrome. We identified 27 cases of NCC-HIV co-infection. The most frequent presentation (61%) was with multiple parenchymal lesions. Seven patients (30%) had other concomitant neurologic infections (e.g., tuberculosis, toxoplasmosis). Thirteen patients received cysticidal therapy, and 85% responded to therapy. Only three patients died (12%). Immunohistochemistry of brain tissue in our case revealed abundant CD3+, CD8+, and CD68+ cells. NCC should be included in the differential diagnosis of neurologic infections in HIV patients in endemic populations. Consideration of the patient's immune status should alert the clinician to potential atypical presentations.