Early alterations in cerebral hemodynamics, brain metabolism, and blood-brain barrier permeability in experimental intracerebral hemorrhage

Association between cerebrospinal fluid lactate concentration and central nervous system disease in dogs

BACKGROUND

Cerebrospinal fluid (CSF) analysis is a sensitive tool for evaluating patients with neurologic diseases but is rarely specific. Biomarkers can be measured from any bodily fluid and can be useful indicators for the presence, severity, and prognosis of diseases.

OBJECTIVES

This study was designed to evaluate if CSF lactate can be used as a biomarker in dogs with central nervous system disease.

METHODS

Peripheral venous blood and CSF were collected from 49 dogs with various intracranial diseases to evaluate correlations between blood and CSF lactate levels. Total nucleated cell count (TNCC) and CSF protein concentrations were also evaluated. All samples obtained were divided into normal (NG) and abnormal (AG) dogs based on a TNCC of ≤5 and >5 cells/μL and a protein concentration of ≤25 and >25 mg/dL, respectively. The AG dogs were further subdivided into those having <100 TNCCs/µL (AGL) and those having >100 TNCCs/µL (AGH). They were also subdivided into groups based on seizure activity (AGS), and inflammatory (AGI), or neoplastic diseases (AGN), and the respective lactate concentrations were then compared.

RESULTS

Lactate concentrations were significantly increased in CSF and venous blood samples in the AG compared with the NG dogs, but no differences were found among the individual disease processes. In all dogs, CSF lactate concentrations were higher than venous blood lactate levels; however, no direct correlation between CSF and blood lactate concentrations was identified.

CONCLUSIONS

Cerebrospinal fluid lactate can be used as a biomarker in clinical settings as it can be measured via a commercially available lactometer immediately after collection without the need for special instrumentation or laboratory personnel.

Activation of peroxisome proliferator-activated receptor-γ by a 12/15-lipoxygenase product of arachidonic acid: a possible neuroprotective effect in the brain after experimental intracerebral hemorrhage

OBJECTIVE In this study, the authors investigated the involvement of 15( S)-hydroxyeicosatetraenoic acid (15(S)-HETE) in the regulation of peroxisome proliferator-activated receptor-γ (PPARγ) after intracerebral hemorrhage (ICH) and its effects on hemorrhage-induced inflammatory response and oxidative stress in an experimental rodent model. METHODS To simulate ICH in a rat model, the authors injected autologous whole blood into the right striatum of male Sprague-Dawley rats. The distribution and expression of 12/15-lipoxygenase (12/15-LOX) were determined by immunohistochemistry and Western blot analysis, respectively. Immunofluorescent double labeling was used to study the cellular localization of 12/15-LOX, and 15(S)-HETE was measured with a 15(S)-HETE enzyme immunoassay kit. Neurological deficits in the animals were assessed through behavioral testing, and apoptotic cell death was determined with terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick-end labeling. RESULTS Rats with ICH had increased expression of 12/15-LOX predominantly in neurons and also in oligodendrocytes, astrocytes, and microglia. Moreover, ICH elevated production of 15(S)-HETE in the brain area ipsilateral to the blood injection. The PPARγ agonist, exogenous 15(S)-HETE, significantly increased PPARγ protein levels and increased PPARγ-regulated gene (i.e., catalase) expression in the ICH rats. Reduced expression of the gene for the proinflammatory protein nuclear factor κB coincided with decreased neuron damage and improved functional recovery from ICH. A PPARγ antagonist, GW9662, reversed the effects of exogenous 15(S)-HETE on the PPARγ-regulated genes. CONCLUSIONS The induction of 15(S)-HETE during simulated ICH suggests generation of endogenous signals of neuroprotection. The effects of exogenous 15(S)-HETE on brain hemorrhage-induced inflammatory responses and oxidative stress might be mediated via PPARγ.

Baicalein Attenuates Neurological Deficits and Preserves Blood-Brain Barrier Integrity in a Rat Model of Intracerebral Hemorrhage

Previous studies have demonstrated that baicalein has protective effects against several diseases, which including ischemic stroke. The effect of baicalein on the blood-brain barrier (BBB) in intracerebral hemorrhage (ICH) and its related mechanisms are not well understood. We aimed to investigate the mechanisms by which baicalein may influence the BBB in a rat model of ICH. The rat model of ICH was induced by intravenous injection of collagenase IV into the brain. Animals were randomly divided into three groups: sham operation, vehicle, and baicalein group. Each group was then divided into subgroups, in which the rats were sacrificed at 24 and 72 h after ICH. We assessed brain edema, behavioral changes, BBB leakage, apoptosis, inducible nitric oxide synthase (iNOS), zonula occludens (ZO)-1, Mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB). Treatment with baicalein reduced brain water content, BBB leakage, apoptosis, and neurologic deficits, compared with vehicle. Baicalein also decreased ICH-induced changes in the levels of iNOS but increased the levels of ZO-1. The protective effect of baicalein on the BBB in ICH rats was possibly invoked by attenuated p-38 MAPK and JNK phosphorylation, and decreased activation of the NF-κB signaling pathway, which may have suppressed gene transcription, including iNOS, and eventually decreased formation of peroxynitrite (ONOO^-). Our results suggest that baicalein exerts a protective effect on BBB disruption in the rat model of ICH. The likely mechanism is via inhibition of MAPKs and NF-κB signaling pathways, leading to decreased formation of iNOS and ONOO^-, thereby improving neurological function.

Protective effects of PGC-1α via the mitochondrial pathway in rat brains after intracerebral hemorrhage

Peroxisome-proliferator-activated receptor co-activator-1α (PGC-1α) is a transcriptional co-activator that coordinately regulates genes required for mitochondrial biogenesis, which stimulates mitochondrial activity. It is also a major factor in the up-regulation of antioxidant activities that are a response to oxidative stress. However, the role of PGC-1α after intracerebral hemorrhage (ICH) has not been studied. The purpose of the present work was to investigate the effects and mechanism of PGC-1α after ICH in the brain. Brain injury was induced by injecting autologous arterial blood (50μL) into the rat brain. PGC-1α siRNAs were injected into rat brains 24h prior to ICH. Then, 72h after ICH, brains were collected for investigation. Post-assessment included western blot analysis, RT-PCR assay, neurobehavioral function testing, measurement of brain water content, high-performance liquid chromatography (HPLC), and projection electron microscopy on ICH rat models. The concentration of PGC-1α was higher in the ipsilateral striatum after ICH, peaking around 72h after ICH. The expression of NRF-1, TFAM, SOD2, UCP2, mitochondrial DNA, ATP concentration, mitochondrial quantity, and brain water content were increased 72h after ICH. However, the neurological score was decreased 72h after ICH. Treatment with PGC-1α siRNAs significantly decreased the neurological score, ATP concentration, number of mitochondria, expression of NRF-1, TFAM, SOD2, UCP2, and mitochondrial DNA, and increased brain water content and formation of mitochondrial myelin layer structures. In conclusion, our data suggest that PGC-1α protects rat brains via a mitochondrial pathway following ICH.

KEY WORDS

PGC-1α intracerebral hemorrhage(ICH); mitochondrial; neuroprotection.

Ischemic brain injury in cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is a common form of cerebral small vessel disease and an important risk factor for intracerebral hemorrhage and cognitive impairment. While the majority of research has focused on the hemorrhagic manifestation of CAA, its ischemic manifestations appear to have substantial clinical relevance as well. Findings from imaging and pathologic studies indicate that ischemic lesions are common in CAA, including white-matter hyperintensities, microinfarcts, and microstructural tissue abnormalities as detected with diffusion tensor imaging. Furthermore, imaging markers of ischemic disease show a robust association with cognition, independent of age, hemorrhagic lesions, and traditional vascular risk factors. Widespread ischemic tissue injury may affect cognition by disrupting white-matter connectivity, thereby hampering communication between brain regions. Challenges are to identify imaging markers that are able to capture widespread microvascular lesion burden in vivo and to further unravel the etiology of ischemic tissue injury by linking structural magnetic resonance imaging (MRI) abnormalities to their underlying pathophysiology and histopathology. A better understanding of the underlying mechanisms of ischemic brain injury in CAA will be a key step toward new interventions to improve long-term cognitive outcomes for patients with CAA.

Computational and Pharmacological Target of Neurovascular Unit for Drug Design and Delivery

The blood-brain barrier (BBB) is a dynamic and highly selective permeable interface between central nervous system (CNS) and periphery that regulates the brain homeostasis. Increasing evidences of neurological disorders and restricted drug delivery process in brain make BBB as special target for further study. At present, neurovascular unit (NVU) is a great interest and highlighted topic of pharmaceutical companies for CNS drug design and delivery approaches. Some recent advancement of pharmacology and computational biology makes it convenient to develop drugs within limited time and affordable cost. In this review, we briefly introduce current understanding of the NVU, including molecular and cellular composition, physiology, and regulatory function. We also discuss the recent technology and interaction of pharmacogenomics and bioinformatics for drug design and step towards personalized medicine. Additionally, we develop gene network due to understand NVU associated transporter proteins interactions that might be effective for understanding aetiology of neurological disorders and new target base protective therapies development and delivery.

Cylophosphamide elicited intracranial hemorrhage via mitochondrial ROS-hif-1α-ATP depleting pathway—preventive trials with folic acid, resveratrol and vitamin E

Hepatic CYP2B metabolizes cyclophosphamide (CP) into acrolein and phosphoramide mustard, which are the ultimate toxic teratogenic compounds.

Transpedicular curettage and drainage versus combined anterior and posterior surgery in infectious spondylodiscitis

BACKGROUND

Hematogeneous infectious spondylodiscitis usually occurs in older immunocompromised patients with other comorbidities. They are usually unable to undergo reconstructive anterior and posterior surgeries. Therefore, an alternative, less aggressive surgical method of transpedicular curettage and drainage was suggested. This study was designed to compare the surgical outcomes for the treatment of hematogeneous infectious spondylodiscitis between transpedicular curettage and drainage technique and conventional combined anterior and posterior surgery.

MATERIALS AND METHODS

Between January 2002 and July 2011, 26 patients underwent surgical treatment for hematogeneous infectious spondylodiscitis. The patients were classified into two groups depending on surgical modality: a transpedicular curettage and drainage (TCD) group and a combined anterior and posterior surgery (CAPS) group.

RESULTS

The TCD group consisted of 10 patients (mean age 68.0 years), and the CAPS group consisted of 16 patients (mean age 58.4 years). The mean postoperative followup periods were 36.9 (months) in the TCD group and 69.9 (months) in the CAPS group. The operation time was 180.6 ± 33.6 minutes in the TCD group and 332.7 ± 74.5 minutes in the CAPS group (P < 0.05). Postoperative independent ambulation began at postoperative 4.9 ± 2.4 days in the TCD group but at postoperative 15.1 ± 15.3 days in the CAPS group (P < 0.05). The postoperative hospital stays were 19.9 ± 7.8 days in the TCD group and 35.4 ± 33.3 days in the CAPS group (P < 0.05). The level of C-reactive proteins decreased significantly in both groups after surgery (P < 0.05).

CONCLUSION

Transpedicular curettage and drainage technique proved to be a useful technique for treating hematogeneous infectious spondylodiscitis in patients who were in poor heath with multiple comorbidities unable to undergo the conventional combined anterior and posterior surgery in a single day in terms of earlier ambulation, shorter hospitalization and similar clinical success rate.

Blood-brain barrier regulation: Environmental cues controlling the onset of barrier properties

The existence of a barrier between the central nervous system (CNS) and the systemic circulation has been described over one hundred years ago. Since the discovery that this barrier was instigated by the barrier properties of the brain endothelial cells, research has focused on the identification of pathways how the brain endothelial cells are instructed to form the highly specialized blood-brain barrier (BBB). Even though our current understanding of BBB development is far from complete, recent literature shows a rise in knowledge of CNS-specific cues that can drive BBB development.

 

In this commentary, we will provide a brief overview of brain selective factors that are critical in the development of barrier properties in the brain endothelium; in particular the role of retinoic acid will be discussed.

Relationship between transcranial Doppler variables in acute stage and outcome of intracerebral hemorrhage

OBJECTIVE

To investigate the characteristics of transcranial Doppler variables in the acute stage of intracerebral hemorrhage (ICH) and its relationship with 14-day death and outcomes at 90 day after onset.

METHODS

Ninety first-time supratentorial nontraumatic ICH patients were prospectively included. Computed tomography and transcranial Doppler examinations were performed on the first, third, seventh, and fourteenth day after onset. Transcranial Doppler variables were obtained from bilateral middle cerebral arteries. The relationship between ICH outcome and the following variables were analyzed: systolic (V(s)), diastolic (V(d)), mean (V(m)) velocities, and pulsatiliy index (PI) from affected and unaffected hemispheres.

RESULTS

Fourteen (15.6%) patients died within 14 days after onset of ICH. The stepwise logistic regression analyses proved presence of intraventricular hemorrhage (OR: 11.91; 95%CI: 1.62-87.42) and PI from unaffected hemisphere (OR: 1.64; 95%CI: 1.19-2.25) to be independent predictors of 14-day death. Forty-eight of the 90 ICH patients performed the transcranial Doppler monitoring at all four time points. V(m) from both hemispheres decreased gradually within 14 days after onset. Among the 48 patients, 22 patients were dependent (modified Rankin Scale ≥ 3) at 90 days after onset. Compared with patients who were independent at 90 days, V(d) (F = 4.98, P = 0.03) and V(m) (F = 7.30, P<0.01) from unaffected hemisphere were significantly lower, while the PI was significantly higher in patients who were dependent (F = 9.84, P<0.01).

CONCLUSIONS

Presence of intraventricular hemorrhage and PI from unaffected hemisphere proved to be independent predictors of 14-day death. Sustained persistent decreases in V(d) and V(m) and increases in PI from the unaffected hemisphere during the acute stage may be related with dependency at 90 days.

Age-related comparisons of evolution of the inflammatory response after intracerebral hemorrhage in rats

In the hours to days after intracerebral hemorrhage (ICH), there is an inflammatory response within the brain characterized by the infiltration of peripheral neutrophils and macrophages and the activation of brain-resident microglia and astrocytes. Despite the strong correlation of aging and ICH incidence, and increasing information about cellular responses, little is known about the temporal- and age-related molecular responses of the brain after ICH. Here, we monitored a panel of 27 genes at 6 h and 1, 3, and 7 days after ICH was induced by injecting collagenase into the striatum of young adult and aged rats. Several molecules (CR3, TLR2, TLR4, IL-1β, TNFα, iNOS, IL-6) were selected to reflect the classical activation of innate immune cells (macrophages, microglia) and the potential to exacerbate inflammation and damage brain cells. Most of the others are associated with the resolution of innate inflammation, alternative pathways of macrophage/microglial activation, and the repair phase after acute injury (TGFβ, IL-1ra, IL-1r2, IL-4, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22). In young animals, the up-regulation of 26 in 27 genes (not IL-4) was detected within the first week. Differences in timing or levels between young and aged animals were detected for 18 of 27 genes examined (TLR2, GFAP, IL-1β, IL-1ra, IL-1r2, iNOS, IL-6, TGFβ, MMP9, MMP12, IL-13, IL-4Rα, IL-13Rα1, IL-13Rα2, MRC1, ARG1, CD163, CCL22), with a generally less pronounced or delayed inflammatory response in the aged animals. Importantly, within this complex response to experimental ICH, the induction of pro-inflammatory, potentially harmful mediators often coincided with resolving and beneficial molecules.

Influence of bacteria on spinal implant-centered infection: an in vitro and in vivo experimental comparison between Staphylococcus aureus and mycobacterium tuberculosis

STUDY DESIGN

an in vitro and in vivo experimental study.

OBJECTIVE

this study was undertaken to evaluate differences in the capability of inducing an implant-centered infection between Staphylococcus aureus and Mycobacterium tuberculosis.

SUMMARY OF BACKGROUND DATA

bacterial infection is still one of the most serious and devastating complications after orthopedic implant surgery despite the advent of new antibiotics and treatment methods.

METHODS

S. aureus and M. tuberculosis were separately cultured with titanium plates. The bacteria colonized on the plates were isolated and cultured on culture medium. They were evaluated and compared by colony-forming units enumeration. Scanning electron microscopy was used to evaluate the difference in the colonization features of the 2 pathogens. In the in vivo experiment, 22 dogs were used to assess the susceptibility to infection after a local bacterial challenge with either S. aureus or M. tuberculosis.

RESULTS

S. aureus showed heavy adhesion and multiplication on the surface of titanium plates in vitro, whereas M. tuberculosis rarely adhered to the surface of the plates. Under scanning electron microscopy, S. aureus colonization was observed: the coccoid was widespread on the surface of the plates but only a few M. tuberculosis cells scattered on the surface of the plates. In in vivo test, the infection rateforthe S. aureus inoculation was higher than that for the M. tuberculosis challenge. The infection rate for the entire test population (n = 44 sites) was 39.58% (19/48). The infection rates were 54.17% (13/24) for the S. aureus challenge and 25% (6/24) for the M. tuberculosis challenge, respectively (P < 0.05).

CONCLUSION

it is less likely for M. tuberculosis to adhere and form a biofilm on an implant surface than S. aureus. Under otherwise identical conditions, M. tuberculosis contamination following instrumented spine surgery might lead to less occurrence of infection than S. aureus contamination.

Simultaneous anterior and posterior surgery in the management of tuberculous spondylitis with psoas abscess in patients with neurological deficits

Study Design

This is a retrospective study.

Purpose

We wanted to evaluate the treatment outcomes of performing simultaneous anterior and posterior surgery for patients with tuberculous spondylitis and psoas abscess.

Overview of Literature

Although various treatment options have been used for spinal tuberculosis, there are only a few reports on the treatment of tuberculous spondylitis with psoas abscess.

Methods

Between March 1997 and February 2006, we performed operations on 14 cases of tuberculous spondylitis with psoas abscess. All the cases underwent anterior debridement with an interbody bone graft and posterior fusion with using pedicle screws.

Results

Under the Frankel classification, 1 case improved by two grades, 10 cases improved by 1 grade and 3 cases demonstrated no change. The Kirkaldy-Willis functional outcomes were classified as excellent in 10 cases and good in 4. One year after surgery, bony union was confirmed in all 14 cases. The mean kyphotic angle of the spinal lesion was 12.4° and the mean lordotic angle at the final follow-up was 6.4°. Postoperative complications (superficial wound infections) were encountered in 2 cases.

Conclusions

Our results demonstrate that anterior debridement with interbody bone grafting and posterior instrumented fusion can provide satisfactory results for treating tuberculous spondylitis with psoas abscess in patients with neurological deficits.

Acute neurovascular unit protective action of pinocembrin against permanent cerebral ischemia in rats

Acute vascular- and neuroprotective effects of pinocembrin (1) were evaluated in a rat model of focal cerebral ischemia. Focal cerebral ischemia was induced by the middle cerebral artery occlusion (MCAO) for 24 h. 5,7-Dihydroxyflavanone (compound 1; at 3, 10, or 30 mg/kg), intravenously injected at 0, 8, and 16 h after MCAO, reduced the cerebral infarct volumes by 47, 39, and 37%, respectively, as visualized by 2,3,5-triphenyltetrazolium chloride staining (P < 0.01). Treatment with 1 also reduced brain swelling and improved behavioral deficits significantly (P < 0.01 and 0.05, respectively). To evaluate the effect of 1 on blood-brain barrier (BBB) disruption, mixture of Evans Blue (EB) and sodium fluorescein (NF) was intravenously injected immediately after MCAO. Global NF/EB uptake and fluorescence imaging of local BBB disruption were measured. Treatment with compound 1 reduced the leakage of both dyes, manifesting a preventive action in BBB integrity. This is the first time to demonstrate that 1 has acute neurovascular protective action against permanent focal cerebral ischemia. The mechanism of neurovascular protective action of 1 is under investigation.

Blood-brain barrier genomics and proteomics: elucidating phenotype, identifying disease targets and enabling brain drug delivery

The blood-brain barrier (BBB) regulates the passage of material between the bloodstream and the brain. Recent genomic and proteomic studies of the BBB have identified some of the unique molecular characteristics of this vascular bed, and have reinforced the concept that the BBB is heavily involved in brain function. Genomic and proteomic techniques have also been used to analyze the molecular events underlying diseases that have BBB involvement, such as multiple sclerosis, Alzheimer's disease, stroke and HIV-1 infection. It is expected that a better understanding of the complex mechanisms that link the BBB to neurological disease will ultimately lead to the development of innovative treatments.

Melatonin decreases neurovascular oxidative/nitrosative damage and protects against early increases in the blood-brain barrier permeability after transient focal cerebral ischemia in mice

We have recently shown that melatonin decreases the late (24 hr) increase in blood-brain barrier (BBB) permeability and the risk of tissue plasminogen activator-induced hemorrhagic transformation following ischemic stroke in mice. In the study, we further explored whether melatonin would reduce postischemic neurovascular oxidative/nitrosative damage and, therefore, improve preservation of the early increase in the BBB permeability at 4 hr after transient focal cerebral ischemia for 60 min in mice. Melatonin (5 mg/kg) or vehicle was given intraperitoneally at the beginning of reperfusion. Hydroethidine (HEt) in situ detection and immunohistochemistry for nitrotyrosine were used to evaluate postischemic accumulation in reactive oxygen and nitrogen species, respectively, in the ischemic neurovascular unit. BBB permeability was evaluated by spectrophotometric and microscopic quantitation of Evans Blue leakage. Relative to controls, melatonin-treated animals not only had a significantly reduced superoxide accumulation in neurovascular units in boundary zones of infarction, by reducing 35% and 54% cytosolic oxidized HEt in intensity and cell-expressing percentage, respectively (P < 0.001), but also exhibited a reduction in nitrotyrosine by 52% (P < 0.01). Additionally, melatonin-treated animals had significantly reduced early postischemic disruption in the BBB permeability by 53% (P < 0.001). Thus, melatonin reduced postischemic oxidative/nitrosative damage to the ischemic neurovascular units and improved the preservation of BBB permeability at an early phase following transient focal cerebral ischemia in mice. The findings further highlight the ability of melatonin in anatomical and functional preservation for the ischemic neurovascular units and its relevant potential in the treatment of ischemic stroke.

Blood-neural barrier: intercellular communication at glio-vascular interface

The blood-neural barrier (BNB), including blood-brain barrier (BBB) and blood-retinal barrier (BRB), is an endothelial barrier constructed by an extensive network of endothelial cells, astrocytes and neurons to form functional "neurovascular units", which has an important role in maintaining a precisely regulated microenvironment for reliable neuronal activity. Although failure of the BNB may be a precipitating event or a consequence, the breakdown of BNB is closely related with the development and progression of CNS diseases. Therefore, BNB is most essential in the regulation of microenvironment of the CNS. The BNB is a selective diffusion barrier characterized by tight junctions between endothelial cells, lack of fenestrations, and specific BNB transporters. The BNB have been shown to be astrocyte dependent, for it is formed by the CNS capillary endothelial cells, surrounded by astrocytic end-foot processes. Given the anatomical associations with endothelial cells, it could be supposed that astrocytes play a role in the development, maintenance, and breakdown of the BNB. Therefore, astrocytes-endothelial cells interaction influences the BNB in both physiological and pathological conditions. If we better understand mutual interactions between astrocytes and endothelial cells, in the near future, we could provide a critical solution to the BNB problems and create new opportunities for future success of treating CNS diseases. Here, we focused astrocyte-endothelial cell interaction in the formation and function of the BNB.

Blood-brain barrier: structural components and function under physiologic and pathologic conditions

The blood-brain barrier (BBB) is the specialized system of brain microvascular endothelial cells (BMVEC) that shields the brain from toxic substances in the blood, supplies brain tissues with nutrients, and filters harmful compounds from the brain back to the bloodstream. The close interaction between BMVEC and other components of the neurovascular unit (astrocytes, pericytes, neurons, and basement membrane) ensures proper function of the central nervous system (CNS). Transport across the BBB is strictly limited through both physical (tight junctions) and metabolic barriers (enzymes, diverse transport systems). A functional polarity exists between the luminal and abluminal membrane surfaces of the BMVEC. As a result of restricted permeability, the BBB is a limiting factor for the delivery of therapeutic agents into the CNS. BBB breakdown or alterations in transport systems play an important role in the pathogenesis of many CNS diseases (HIV-1 encephalitis, Alzheimer's disease, ischemia, tumors, multiple sclerosis, and Parkinson's disease). Proinflammatory substances and specific disease-associated proteins often mediate such BBB dysfunction. Despite seemingly diverse underlying causes of BBB dysfunction, common intracellular pathways emerge for the regulation of the BBB structural and functional integrity. Better understanding of tight junction regulation and factors affecting transport systems will allow the development of therapeutics to improve the BBB function in health and disease.

Puromycin-purified rat brain microvascular endothelial cell cultures exhibit improved barrier properties in response to glucocorticoid induction

In vitro blood-brain barrier (BBB) models using primary rat brain microvessel endothelial cells (BMEC) are often hampered by a lack of culture purity and poor barrier properties. To address these problems, the translation inhibitor puromycin was used to purify rat BMEC cultures. BMEC purities of 99.8% were routinely attained using puromycin treatment, and this technique proved to be far superior to other purification methods of similar difficulty. In contrast to cultures without puromycin treatment, purity of puromycin-treated cultures was unaffected by initial seeding density. Next, rat BMEC monolayer transendothelial electrical resistance (TEER) was increased by glucocorticoid treatment with either corticosterone (CORT) or hydrocortisone (HC), and a corresponding decrease in monolayer permeability to small molecules was observed. Importantly, cultures treated with both puromycin and glucocorticoid attained significantly higher TEER values (CORT 168 +/- 13 Omega x cm2; HC 218 +/- 66 Omega x cm2) than those treated by the glucocorticoid alone (CORT 57 +/- 5 Omega x cm2; HC 70 +/- 2 Omega x cm2). Glucocorticoid induction resulted in BMEC morphological changes that accompanied the increases in TEER, and BMEC tight junctions exhibited improved integrity as visualized by the localization of tight junction proteins zonula occluden-1, occludin and claudin-5. The combined use of puromycin and glucocorticoid therefore provides an in vitro system that is well suited for molecular level BBB investigations.

Prognostic Significance of Blood Brain Barrier Permeability in Acute Hemorrhagic Stroke

BACKGROUND

Blood brain barrier (BBB) disruption is accompanied by edema in the surrounding areas of the intracerebral hemorrhage (ICH). The aim of the study was to clarify the correlation between BBB breakdown and outcome in ICH.

PATIENTS

Twenty-seven patients with primary ICH were included in the study. Each patient underwent CT and DTPA-SPECT, and the National Institutes of Health (NIH) and modified Rankin score were performed as well.

RESULTS

DTPA-SPECT had a significant correlation with the modified Rankin score after 3 months (p = 0.008) and 6 months (p = 0.01). The CT scan was directly correlated with the NIH score on days 1, 7 and 30 (p = 0.01, p = 0.01 and p = 0.04, respectively). No correlation was found between DTPA-SPECT and CT scan data.

CONCLUSIONS

The degree of BBB breakdown, as imaged by the DTPA-SPECT technique, was directly correlated with the late functional outcome. The CT scan has an inverse correlation with the NIH score. These findings may have broad clinical implications.

The blood-brain barrier/neurovascular unit in health and disease

The blood-brain barrier (BBB) is the regulated interface between the peripheral circulation and the central nervous system (CNS). Although originally observed by Paul Ehrlich in 1885, the nature of the BBB was debated well into the 20th century. The anatomical substrate of the BBB is the cerebral microvascular endothelium, which, together with astrocytes, pericytes, neurons, and the extracellular matrix, constitute a "neurovascular unit" that is essential for the health and function of the CNS. Tight junctions (TJ) between endothelial cells of the BBB restrict paracellular diffusion of water-soluble substances from blood to brain. The TJ is an intricate complex of transmembrane (junctional adhesion molecule-1, occludin, and claudins) and cytoplasmic (zonula occludens-1 and -2, cingulin, AF-6, and 7H6) proteins linked to the actin cytoskeleton. The expression and subcellular localization of TJ proteins are modulated by several intrinsic signaling pathways, including those involving calcium, phosphorylation, and G-proteins. Disruption of BBB TJ by disease or drugs can lead to impaired BBB function and thus compromise the CNS. Therefore, understanding how BBB TJ might be affected by various factors holds significant promise for the prevention and treatment of neurological diseases.

Chronic inflammatory pain leads to increased blood-brain barrier permeability and tight junction protein alterations

The blood-brain barrier (BBB) maintains brain homeostasis by limiting entry of substances to the central nervous system through interaction of transmembrane and intracellular proteins that make up endothelial cell tight junctions (TJs). Recently it was shown that the BBB can be modulated by disease pathologies including inflammatory pain. This study examined the effects of chronic inflammatory pain on the functional and molecular integrity of the BBB. Inflammatory pain was induced by injection of complete Freund's adjuvant (CFA) into the right plantar hindpaw in female Sprague-Dawley rats under halothane anesthesia; control animals were injected with saline. Edema and hyperalgesia were assessed by plethysmography and infrared paw-withdrawal latency. At 72 h postinjection, significant edema formation and hyperalgesia were noted in the CFA-treated rats. Examination of permeability of the BBB by in situ perfusion of [14C]sucrose while rats were under pentobarbital anesthesia demonstrated that CFA treatment significantly increased brain sucrose uptake. Western blot analysis of BBB TJ proteins showed no change in expression of zonula occludens-1 (an accessory protein) or actin (a cytoskeletal protein) with CFA treatment. Expression of the transmembrane TJ proteins occludin and claudin-3 and -5 significantly changed with CFA treatment with a 60% decrease in occludin, a 450% increase in claudin-3, and a 615% increase in claudin-5 expression. This study demonstrates that during chronic inflammatory pain, alterations in BBB function are associated with changes in specific transmembrane TJ proteins.

Posterior instrumentation using compressive laminar hooks and anterior interbody arthrodesis for the treatment of tuberculosis of the lower lumbar spine

STUDY DESIGN

A retrospective review with clinical and radiologic assessment was conducted.

OBJECTIVE

To demonstrate the feasibility of posterior short segment augmentation with lamina hook and anterior lumbar interbody arthrodesis in tuberculosis of the lumbar spine by evaluating clinical results, fusion status, and sagittal angle.

SUMMARY OF BACKGROUND DATA

There are few articles in the literature describing circumferential treatment of lumbar tuberculosis. We have had significant experience with a uniform operative technique for the treatment of this relatively rare condition and report our results with a minimum 2-year follow-up.

METHODS

Twenty-three patients with tuberculosis of the lower lumbar spine underwent posterior instrumentation with laminar hooks and anterior interbody arthrodesis by a single surgeon. The clinical outcomes were evaluated with preoperative and postoperative questionnaires, and the radiographs were independently analyzed with respect to fusion status and sagittal angle. RESULTS.: The mean follow-up period was 28.7 months (range, 24-39 months). The average preoperative, immediate postoperative, and final follow-up sagittal angles were 2.7 degrees, -14.1 degrees, and -11.5 degrees, respectively. There was a mean reduction of 16.7 degrees (range, 9 degrees-23 degrees) after surgery. Two patients had a correction loss more than 5 degrees during the follow-up period. Bony fusion was obtained in all patients. There was no recurrence of the disease. CONCLUSION.: This technique appears to be effective in stabilizing the vertebrae, restoring lordosis, achieving a solid fusion, and improving clinical outcome without sacrificing additional motion segments.

Imaging of haemorrhagic stroke

Computed tomography (CT) is the reference standard for the imaging of acute non-traumatic intracranial haemorrhage. The sensitivity with which CT detects haemorrhage falls with time and lumber puncture remains mandatory for the exclusion of subarachnoid haemorrhage (SAH). Magnetic resonance (MR) imaging is, however, superior to CT in the subacute and chronic stages after haemorrhage. MR in addition offers pathophysiological information that can help with assessment of both the aetiology of and complications arising from both SAH and intra-parenchymal haemorrhage.

Combined anterior and posterior surgeries in the treatment of spinal tuberculous spondylitis

Methods for the treatment of tuberculous spondylitis still are controversial. The authors treated 32 consecutive patients with a two-stage surgical technique combined with antituberculous chemotherapy for 1 year. After anterior debridement, fusion with autogenous anterior iliac tricortical strut bone graft was done, and in a second stage, posterior instrumentation and fusion with autogenous posterior iliac corticocancellous bone graft was done 11 days (range, 4-22 days) later. Postoperatively, patients were encouraged to ambulate with brace protection as early as possible. Twenty-nine patients were followed up for a minimum of 2 years (median, 4.7 years; range, 2-10 years) of whom 28 patients achieved solid fusion (97%). All patients had improvement of back pain including the only patient with pseudarthrosis. Neurologic deficits completely recovered in 84% (16 of 19) of patients after 3 months. Kyphotic deformity improved in all 29 patients (34.6 degrees versus 17.3 degrees ) with the average correction angle of 17.3 degrees. Clinically, 27 patients had achieved a satisfactory outcome (93%). There were no evident surgical complications. The authors, therefore, recommend a two-stage surgical technique combined with antituberculous chemotherapy to treat patients with severe vertebral body destruction attributable to tuberculosis because of its high success rate and a low complication rate.

Marked anemic hypoxia deteriorates cerebral hemodynamics and brain metabolism during massive intracerebral hemorrhage

The present study was undertaken to investigate the influence of imposed anemic hypoxia on cerebral hemodynamics and metabolism in a condition of massive ICH. Two groups of eight dogs, with a target hemoglobin concentration of 12 g/dl in nonanemic and 6 g/dl in anemic group, were included. Before the onset of the insult, anemic group had a significant reduction (p<0.05) in cerebral arteriovenous oxygen content difference (AVDO2), accompanied with a significant rise (p<0.05) in flow velocity (FV) of the basilar artery and cerebral extraction fraction of oxygen (CEO2) and a lower brain-tissue lactate clearance than did nonanemic group. Shortly after ICH, both groups displayed significant reductions (p<0.05) in FV, CEO2 and AVDO2, and simultaneous rises in arteriovenous lactate concentrations. In nonanemic group, the CEO2 and AVDO2 gradually returned after an initial decrease, and then the arteriovenous lactate concentrations slowly decreased. In contrast, anemic group showed progressive reductions in CEO2 and AVDO2 associated with persistent rises in arteriovenous lactate concentrations. Consequently, anemic group exhibited significantly greater brain-tissue lactate clearances (p<0.05), occurring at 10 min and 5 h postinjury, than did nonanemic group, although the former had relatively higher levels of CEO2 up to 3 h postinjury. We conclude that anemic hypoxia modulates a favorable change in cerebral hemodynamics and oxygenation, while it progressively deteriorates after an initial reduction during massive ICH, thus facilitating cerebral anaerobic glycolysis in biphasic periods. These results point to a complex interaction between cerebral hemodynamics, oxygen supply and glycolysis homeostasis upon the addition of anemic hypoxia in severe stress conditions of the brain.