Quantitative analysis of cytokine-induced vascular toxicity and vascular leak in the mouse brain

Early Axonal Injury and Delayed Cytotoxic Cerebral Edema are Associated with Microglial Activation in a Mouse Model of Sepsis

Sepsis-induced brain injury is associated with an acute deterioration of mental status resulting in cognitive impairment and acquisition of new functional limitations in sepsis survivors. However, the exact nature of brain injury in this setting is often subtle and remains to be fully characterized both in preclinical studies and at the bedside. Given the translation potential for the use of magnetic resonance imaging (MRI) to define sepsis-induced brain injury, we sought to determine and correlate the cellular changes with neuroradiographic presentations in a classic murine model of sepsis induced by cecal ligation and puncture (CLP). Sepsis was induced in 6-10-week-old male C57/BL6 mice by CLP. We used immunohistochemistry (IHC) to define neuropathology in a mouse model of sepsis along with parallel studies using MRI, focusing on cerebral edema, blood-brain barrier (BBB) disruption, and microglial activation on days 1 and 4 days after CLP. We demonstrate that septic mice had evidence of early axonal injury, inflammation, and robust microglial activation on day 1 followed by cytotoxic edema on day 4 in the cortex, thalamus, and hippocampus in the absence of BBB disruption. We note the superiority of the MRI to detect subtle brain injury and cytotoxic cerebral edema in comparison with the traditional gold standard assessment, i.e., percent brain water (wet-dry weight method). We conclude that inflammatory changes in the septic brain can be detected in real time, and further studies are needed to understand axonal injury and the impact of inhibition of microglial activation on the development of cerebral edema.

Accelerated vascular aging and persistent cognitive impairment in older female breast cancer survivors

Advances in breast cancer treatment have markedly increased survivorship over the past three decades, with over 3.1 million survivors expected to live into their 70s and 80s. Without symptom relief interventions, nearly 35% of these survivors will have life-altering and distressing cognitive symptoms. This pilot study explored associations between serum markers of vascular aging, laterality in cerebral oxygenation, and severity of cognitive impairment in women, 12-18 months after chemotherapy for stage 2/3 invasive ductal breast cancer. Fifteen women (52-84 years) underwent a brief cognitive assessment (Montreal Cognitive Assessment [MOCA]) and blood draws to assess markers of vascular aging (interleukin-6 [IL-6], tumor necrosis factor alpha [TNF-α], C-reactive protein [CRP], and insulin growth factor-1 [IGF-1]). All underwent a computer-based test protocol that is known to increase blood flow within the frontal lobes. Percent cerebral oxyhemoglobin saturation (rcSO₂) was recorded during and after testing. Laterality in rcSO₂ was defined by ≥ 3% difference between left and right rcSO₂ (|rcSO₂ mean_{RIGHT -} mean_LEFT|). Eight participants had MOCA scores between 21 and 25 points, suggestive of mild cognitive impairment. Neither CRP (r = -.24) nor IL-6 (r = .34) nor TNF-α (r = .002) were associated with MOCA scores. Higher IL-6 was associated with greater laterality (r = .41). MOCA scores were significantly lower in subjects with laterality in rcSO₂ than in those without laterality (F_(1,14) = 13.5, p = 003). Lower IGF-1 was significantly associated with greater laterality (r = - .66, p = .007) and lower cognitive function (r = .58). These findings suggest that persistent cognitive impairment is associated with phenotypical changes consistent with accelerated vascular aging.

Imaging in sepsis-associated encephalopathy--insights and opportunities

Sepsis-associated encephalopathy (SAE) refers to a clinical spectrum of acute neurological dysfunction that arises in the context of sepsis. Although the pathophysiology of SAE is incompletely understood, it is thought to involve endothelial activation, blood-brain barrier leakage, inflammatory cell migration, and neuronal loss with neurotransmitter imbalance. SAE is associated with a high risk of mortality. Imaging studies using MRI and CT have demonstrated changes in the brains of patients with SAE that are also seen in disorders such as stroke. Next-generation imaging techniques such as magnetic resonance spectroscopy, diffusion tensor imaging and PET, as well as experimental imaging modalities, provide options for early identification of patients with SAE, and could aid in identification of pathophysiological processes that represent possible therapeutic targets. In this Review, we explore the recent literature on imaging in SAE, relating the findings of these studies to pathological data and experimental studies to obtain insights into the pathophysiology of sepsis-associated neurological dysfunction. Furthermore, we suggest how novel imaging technologies can be used for early-stage proof-of-concept and proof-of-mechanism translational studies, which may help to improve diagnosis in SAE.

Severe adverse events from the treatment of advanced melanoma: a systematic review of severe side effects associated with ipilimumab, vemurafenib, interferon alfa-2b, dacarbazine and interleukin-2

BACKGROUND

Current immunomodulatory agents for stage III and IV melanoma exert different mechanisms of action that manifest in distinct adverse events.

OBJECTIVE

This systematic review aims to synthesize safety data from clinical trials on ipilimumab, vemurafenib, interferon (IFN) alfa-2b, dacarbazine and interleukin (IL)-2 to elucidate the severe adverse events associated with each melanoma therapy.

METHODS

Through a systematic search using MEDLINE, EMBASE and the Cochrane Central Register between January 1, 2010 and June 1, 2012, we identified 32 clinical trials with 5802 subjects that met the inclusion criteria.

RESULTS

Ipilimumab was associated with immune-mediated diarrhea and colitis, with an incidence rate of 0.0017 cases per 100 person-years. Patients receiving vemurafenib developed keratoacanthomas and cutaneous squamous cell carcinoma at an incidence rate of 0.0025 cases per 100 person-years. Treatment with IFN alfa-2b precipitated depression at an incidence rate of 0.0002 cases per 100 person-years. Dacarbazine was associated with respiratory toxicity and dyspnea, with incidence rates of 0.0001 and 0.00008 cases per 100 person-years, respectively. IL-2 treatment induced vascular leak syndrome (VLS), with symptoms of hypotension and oliguria, was observed at incidence rates of 0.17 and 0.15 cases per 100 person-years, respectively. Findings may serve as a foundation for future research in this area and guide clinical recommendations.

Imaging inflammation: molecular strategies to visualize key components of the inflammatory cascade, from initiation to resolution

Dysregulation of inflammation is central to the pathogenesis of innumerable human diseases. Understanding and tracking the critical events in inflammation are crucial for disease monitoring and pharmacological drug discovery and development. Recent progress in molecular imaging has provided novel insights into spatial associations, molecular events and temporal sequelae in the inflammatory process. While remaining a burgeoning field in pre-clinical research, increasing application in man affords researchers the opportunity to study disease pathogenesis in humans in situ thereby revolutionizing conventional understanding of pathophysiology and potential therapeutic targets. This review provides a description of commonly used molecular imaging modalities, including optical, radionuclide and magnetic resonance imaging, and details key advances and translational opportunities in imaging inflammation from initiation to resolution.