Effect of hemopexin treatment on outcome after intracerebral hemorrhage in mice.

Heme release from hemoglobin may contribute to secondary injury after intracerebral hemorrhage (ICH). The primary endogenous defense against heme toxicity is hemopexin, a 57 kDa glycoprotein that is depleted in the CNS after hemorrhagic stroke. We hypothesized that systemic administration of exogenous hemopexin would reduce perihematomal injury and improve outcome after experimental ICH. Intraperitoneal treatment with purified human plasma hemopexin beginning 2 h after striatal ICH induction and repeated daily for the following two days reduced blood-brain barrier disruption and cell death at 3 days. However, it had no effect on neurological deficits at 4 or 7 days or striatal cell viability at 8 days. Continuous daily hemopexin administration had no effect on striatal heme content at 3 or 7 days, and did not attenuate neurological deficits, inflammatory cell infiltration, or perihematomal cell viability at 8 days. These results suggest that systemic hemopexin treatment reduces early injury after ICH, but this effect is not sustained, perhaps due to an imbalance between striatal tissue heme and hemopexin content at later time points. Future studies should investigate its effect when administered by methods that more efficiently target CNS delivery.

Reactivation of Epstein-Barr Virus Hepatitis in T/Natural Killer (NK) Cells Mimicking Liver T/NK-Cell Lymphoma.

Diagnosis of Epstein-Barr virus (EBV)-associated hepatitis, chronic active EBV infection, and EBV-associated lymphoproliferative diseases, is always challenging due to the overlapping symptoms and lack of diagnostic criteria. We report such a case of a 40-year-old man with unremarkable past medical history. He presented with fever of unknown origin for 1 month with jaundice for 2 days. Physical exams were unremarkable with body temperature at 98.6 °F. His liver function tests were elevated with alanine transaminase (ALT) 559 U/L, aspartate transaminase (AST) 892 U/L, alkaline phosphatase 319 U/L and total bilirubin 4.4 mg/dL. Computed tomography of his chest, abdomen and pelvis did not show lymphadenopathy or hepatosplenomegaly. A liver biopsy showed moderately acute hepatitis with hemophagocytosis, positive Epstein-Barr virus encoding RNA (EBER) in situ hybridization in CD3 and CD4-positive T cells and CD56-positive natural killer (NK) cells. CD20 was negative. The pathology diagnosis was consistent with reactivation of EBV hepatitis but NK-cell lymphoma needs to be excluded. Steatohepatitis with mild activity was present. His blood EBV DNA was 846,000 copies/mL and continued to increase to 2,000,000 copies/mL. Flow cytometric analysis of his bone marrow revealed an increased NK-cell activity but no T/NK-cell lymphoma was identified. Initial treatment with rituxan, etoposide and/or ruxolitinib/acyclovir failed or only had limited effect. However, subsequent valganciclovir greatly improved his conditions. In his 3 months follow-up, the patient was doing well with almost normal liver function tests except mildly elevated ALT (95 U/L) that was due to mild steatohepatitis. EBV DNA PCR was 2,009 copies/mL. To the best of our knowledge, this is the first documented case with reactivation of EBV hepatitis mimicking NK-cell lymphoma in the English literature. With appropriate anti-EBV viral treatments, the patient eventually became asymptomatic and was able to return to his routine life.

Non-immunogenic utrophin gene therapy for the treatment of muscular dystrophy animal models.

The essential product of the Duchenne muscular dystrophy (DMD) gene is dystrophin1, a rod-like protein2 that protects striated myocytes from contraction-induced injury3,4. Dystrophin-related protein (or utrophin) retains most of the structural and protein binding elements of dystrophin5. Importantly, normal thymic expression in DMD patients6 should protect utrophin by central immunologic tolerance. We designed a codon-optimized, synthetic transgene encoding a miniaturized utrophin (µUtro), deliverable by adeno-associated virus (AAV) vectors. Here, we show that µUtro is a highly functional, non-immunogenic substitute for dystrophin, preventing the most deleterious histological and physiological aspects of muscular dystrophy in small and large animal models. Following systemic administration of an AAV-µUtro to neonatal dystrophin-deficient mdx mice, histological and biochemical markers of myonecrosis and regeneration are completely suppressed throughout growth to adult weight. In the dystrophin-deficient golden retriever model, µUtro non-toxically prevented myonecrosis, even in the most powerful muscles. In a stringent test of immunogenicity, focal expression of µUtro in the deletional-null German shorthaired pointer model produced no evidence of cell-mediated immunity, in contrast to the robust T cell response against similarly constructed µDystrophin (µDystro). These findings support a model in which utrophin-derived therapies might be used to treat clinical dystrophin deficiency, with a favorable immunologic profile and preserved function in the face of extreme miniaturization.

Targeting heme oxygenase after intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is the primary event in approximately 10% of strokes, and has higher rates of morbidity and mortality than ischemic stroke. Experimental evidence suggests that the toxicity of hemoglobin and its degradation products contributes to secondary injury that may be amenable to therapeutic intervention. Hemin, the oxidized form of heme, accumulates in intracranial hematomas to cytotoxic levels. The rate limiting step of its breakdown is catalyzed by the heme oxygenase (HO) enzymes, which consist of inducible HO-1 and constitutively-expressed HO-2. The effect of these enzymes on perihematomal injury and neurological outcome has been investigated in ICH models using both genetic and pharmacological approaches to alter their expression, with variable results reported. These findings are summarized and reconciled in this review; therapeutic strategies that may optimize HO expression and activity after ICH are described.

Systemic hemin therapy attenuates blood-brain barrier disruption after intracerebral hemorrhage.

Injury to the blood-brain barrier (BBB) is a key feature of intracerebral hemorrhage (ICH) and may contribute to perihematomal cell injury. Pretreatment with the heme oxygenase (HO)-1 inducer hemin improves barrier function and neurological outcome in experimental models of traumatic and ischemic CNS injury. Since hemin is already in clinical use to treat acute porphyrias, this translational study was designed to test its effect on BBB function when initiated after ICH in two mouse models. At a dose similar to those used in most preconditioning studies (26mg/kg i.p.), post-hemorrhage treatment with hemin reduced parenchymal extravasation of Evans blue by about three-quarters in both the blood injection and collagenase ICH models. Similar efficacy was observed when treatment was begun at 1 or 3h. At the lower dose that is currently in clinical use (4mg/kg beginning at 3h), hemin also improved barrier function in both models, as assessed by both Evans blue and FITC-dextran leakage; however, it was somewhat less potent, reducing Evans blue leakage by about half. This dose was nevertheless sufficient to attenuate striatal cell loss and accelerate neurological recovery. Consistent with prior observations, striatal HO-1 expression was increased by hemin, and was localized to perivascular cells. These results suggest that hemin may be an effective therapy for ICH with a clinically relevant time window. Further study of the repurposing of this old drug seems warranted.

Optical bedside monitoring of cerebral blood flow in acute ischemic stroke patients during head-of-bed manipulation.

BACKGROUND AND PURPOSE: A primary goal of acute ischemic stroke (AIS) management is to maximize perfusion in the affected region and surrounding ischemic penumbra. However, interventions to maximize perfusion, such as flat head-of-bed (HOB) positioning, are currently prescribed empirically. Bedside monitoring of cerebral blood flow (CBF) allows the effects of interventions such as flat HOB to be monitored and may ultimately be used to guide clinical management. METHODS: Cerebral perfusion was measured during HOB manipulations in 17 patients with unilateral AIS affecting large cortical territories in the anterior circulation. Simultaneous measurements of frontal CBF and arterial flow velocity were performed with diffuse correlation spectroscopy and transcranial Doppler ultrasound, respectively. Results were analyzed in the context of available clinical data and a previous study. RESULTS: Frontal CBF, averaged over the patient cohort, decreased by 17% (P=0.034) and 15% (P=0.011) in the ipsilesional and contralesional hemispheres, respectively, when HOB was changed from flat to 30°. Significant (cohort-averaged) changes in blood velocity were not observed. Individually, varying responses to HOB manipulation were observed, including paradoxical increases in CBF with increasing HOB angle. Clinical features, stroke volume, and distance to the optical probe could not explain this paradoxical response. CONCLUSIONS: A lower HOB angle results in an increase in cortical CBF without a significant change in arterial flow velocity in AIS, but there is variability across patients in this response. Bedside CBF monitoring with diffuse correlation spectroscopy provides a potential means to individualize interventions designed to optimize CBF in AIS.

Influence of probe pressure on the diffuse correlation spectroscopy blood flow signal: extra-cerebral contributions.

A pilot study explores relative contributions of extra-cerebral (scalp/skull) versus brain (cerebral) tissues to the blood flow index determined by diffuse correlation spectroscopy (DCS). Microvascular DCS flow measurements were made on the head during baseline and breath-holding/hyperventilation tasks, both with and without pressure. Baseline (resting) data enabled estimation of extra-cerebral flow signals and their pressure dependencies. A simple two-component model was used to derive baseline and activated cerebral blood flow (CBF) signals, and the DCS flow indices were also cross-correlated with concurrent Transcranial Doppler Ultrasound (TCD) blood velocity measurements. The study suggests new pressure-dependent experimental paradigms for elucidation of blood flow contributions from extra-cerebral and cerebral tissues.

A rapid fluorescent method to quantify neuronal loss after experimental intracerebral hemorrhage.

Neuronal loss in tissue surrounding an intracerebral hemorrhage (ICH) is usually quantified by labor-intensive histological methods that are subject to bias. Fluorescent protein expression has been successfully used as a marker of cell viability in vitro and in retinal studies in vivo, but not in any ICH model to date. The potential of this approach was investigated using transgenic mice that constitutively express the red fluorescent protein variant dTomato in central neurons under the control of the Thy1 promoter. Breeding and growth of these mice were similar to their wild-type counterparts; behavioral phenotyping by digital analysis of home cage video recordings detected no differences. Bright fluorescence was evident in fresh brain samples with minimal background fluorescence, and was reduced in tissue surrounding the hematoma. In order to assess fluorescence loss as an injury marker in a planned study, these mice were crossed with heme oxygenase (HO)-2 knockouts and wild-type controls; striatal hemorrhage was induced by stereotactic injection of collagenase. Fluorescence in hemorrhagic striata was reduced to 86.4±3.9%, 62.2±5.1%, and 58.3±3.0% of contra-lateral on days 1, 4 and 8, respectively, and correlated closely with reduction in striatal cell viability as quantified by MTT assay. HO-2 knockout and wild-type values did not differ significantly. Similar results were observed with stereological cell counts of striatal neurons identified by NeuN immunoreactivity. These results suggest that loss of constitutive dTomato fluorescence is an accurate and efficient marker of neuronal loss in tissue surrounding a striatal hematoma.

[Evaluation of coma after cardiopulmonary resuscitation].

OBJECTIVE: To investigate the accurate and objective methods of evaluating coma after cardiopulmonary resuscitation. METHODS: Cases that were still in coma 24 hours after cardiopulmonary resuscitation were continuously observed and evaluated between April 2002 and November 2004. The methods of evaluation included various clinical examinations, for instance conscious state, Glasgow coma score (GCS), brain stem inflection, spinal reflexes and so on. Other methods of evaluation included laboratory examinations, such as electroencephalography (EEG), brain auditory evoked potential (BAEP), short latent somatosensory evoked potential (SLSEP) and transcranial doppler (TCD). RESULTS: 24 of a series of 35 cases (68.6%) were in deep coma. The GCS is score 3. EEG evaluated was not less than grade IV in all except 4; BAEP evaluated was grade III in all except 3; SLSEP evaluated was grade III in all except 1. 24 cases died within 1 month and 11 of them (45.8%) were evaluated as having brain death and Glasgow outcome score (GOS) was grade I. 11 of the 35 cases survived and their state of consciousness changed from deep coma to coma vigil, EEG evaluated was grade I in 5 cases. BAEP and SLSEP were grade I in the 3 cases evaluated and GOS is grade II. 2 cases (18.2%) regain consciousness at the time of 35 and 90 days after cardiopulmonary resuscitation and their GOS was grade IV and grade III respectively. CONCLUSION: Combined and continuous observation of clinical manifestations and laboratory parameters can accurately and objectively evaluate coma after cardiopulmonary resuscitation.