Experimental acute pancreatitis results in increased blood-brain barrier permeability in the rat: a potential role for tumor necrosis factor and interleukin 6

Objective sleep measures in chronic fatigue syndrome patients: A systematic review and meta-analysis

Patients with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) often report disrupted and unrefreshing sleep in association with worsened fatigue symptoms. However, the nature and magnitude of sleep architecture alteration in ME/CFS is not known, with studies using objective sleep measures in ME/CFS generating contradictory results. The current manuscript aimed to review and meta-analyse of case-control studies with objective sleep measures in ME/CSF. A search was conducted in PubMed, Scopus, Medline, Google Scholar, and Psychoinfo databases. After review, 24 studies were included in the meta-analysis, including 20 studies with 801 adults (ME/CFS = 426; controls = 375), and 4 studies with 477 adolescents (ME/CFS = 242; controls = 235), who underwent objective measurement of sleep. Adult ME/CFS patients spend longer time in bed, longer sleep onset latency, longer awake time after sleep onset, reduced sleep efficiency, decreased stage 2 sleep, more Stage 3, and longer rapid eye movement sleep latency. However, adolescent ME/CFS patients had longer time in bed, longer total sleep time, longer sleep onset latency, and reduced sleep efficiency. The meta-analysis results demonstrate that sleep is altered in ME/CFS, with changes seeming to differ between adolescent and adults, and suggesting sympathetic and parasympathetic nervous system alterations in ME/CFS.

Role of interleukin-6 and interleukin-10 in morphological and functional changes of the blood-brain barrier in hypertriglyceridemia

BACKGROUND

Hypertriglyceridemia is closely linked to atherosclerosis related inflammatory processes and blood-brain barrier (BBB) dysfunction. Using apolipoprotein B-100 (APOB-100) transgenic mice, an animal model of chronic hypertriglyceridemia, we analyzed BBB function and morphology in vitro and ex vivo. Our objective was to determine which BBB characteristics are produced mainly by interleukin (IL)-6, an atherosclerosis promoting cytokine, and whether these actions can be antagonized by IL-10, an anti-inflammatory cytokine.

METHODS

Brain endothelial and glial cell cultures and brain microvessels were isolated from wild type (WT) and APOB-100 transgenic mice and were treated with IL-6, IL-10 and their combination. First, IL-6 and IL-10 production was measured in WT and APOB-100 microvessels using qPCR. Then functional parameters of endothelial cell cultures were analyzed and immunocytochemistry for key BBB proteins was performed.

RESULTS

IL-6 mRNA levels were higher in brain microvessels than in brain parenchyma of APOB-100 transgenic mice. Transendothelial electric resistance and P-glycoprotein activity were lower, and paracellular permeability was higher in cultured APOB-100 brain endothelial cells. These features were sensitive to both IL-6 and IL-10 treatments. A decreased P-glycoprotein immunostaining was measured in transgenic endothelial cells under control conditions and in WT cells after treating them with IL-6. This effect was antagonized by IL-10. Changes in immunostaining for tight junction proteins were observed after IL-6 exposure, which were in part antagonized by IL-10. In glial cell cultures an increase in aquaporin-4 immunolabeling in the transgenic group and an increase in microglia cell density in WT glia cultures was detected after IL-6 treatment, which was antagonized by IL-10. In isolated brain microvessels a decrease in P-glycoprotein immunolabeled area fraction was measured in APOB-100 microvessels under control conditions and in WT microvessels after every cytokine treatment. ZO-1 immunolabeling showed characteristics similar to that of P-glycoprotein. No change was seen in claudin-5 and occludin immunoreactive area fractions in microvessels. A decrease in aquaporin-4 immunoreactivity was measured in WT microvessels treated by IL-6, which was antagonized by IL-10.

CONCLUSION

IL-6 produced in microvessels contributes to BBB impairment observed in the APOB-100 mice. We showed that IL-10 partly antagonizes the effects of IL-6 at the BBB.

Posterior Reversible Encephalopathy Syndrome in the Setting of Asparaginase-associated Pancreatitis in 2 Pediatric Patients With Acute Leukemia

Asparaginase, a critical component of current pediatric acute leukemia treatment protocols, is associated with a number of serious side effects, one of which is pancreatitis. Pancreatitis can result in significant morbidity and mortality from necrosis, pseudocyst formation, hemorrhage, systemic inflammation, intestinal perforation, and sepsis. Another rare complication of pancreatitis is posterior reversible encephalopathy syndrome, likely mediated by systemic inflammation secondary to pancreatic autodigestion and proinflammatory cytokine-mediated vascular endothelial damage. Here, we review this association in the literature and report 2 pediatric patients with leukemia who developed posterior reversible encephalopathy syndrome in the setting of asparaginase-associated pancreatitis.

Predisposing Factors and Neurologic Outcomes of Patients with Elevated Serum Amylase and/or Lipase after Out-of-Hospital Cardiac Arrest: A Retrospective Cohort Study

This study investigated the patient outcomes, incidence, and predisposing factors of elevated pancreatic enzyme levels after OHCA. We conducted a retrospective cohort study of patients treated with targeted temperature management (TTM) after out-of-hospital cardiac arrest (OHCA). Elevation of pancreatic enzyme levels was defined as serum amylase or lipase levels that were at least three times the upper limit of normal. The factors associated with elevated pancreatic enzyme levels and their association with neurologic outcomes and mortality 28 days after OHCA were analyzed. Among the 355 patients, 166 (46.8%) patients developed elevated pancreatic enzyme levels. In the multivariable analysis (odds ratio, 95% confidence interval), initial shockable rhythm (0.62, 0.39−0.98, p = 0.04), time from collapse to return of spontaneous circulation (1.02, 1.01−1.04, p < 0.001), and history of coronary artery disease (1.7, 1.01−2.87, p = 0.046) were associated with elevated pancreatic enzyme levels. After adjusting for confounding factors, elevated pancreatic enzyme levels were associated with neurologic outcomes (5.44, 3.35−8.83, p < 0.001) and mortality (3.74, 2.39−5.86, p < 0.001). Increased pancreatic enzyme levels are common in patients treated with TTM after OHCA and are associated with unfavorable neurologic outcomes and mortality at 28 days after OHCA.

Blood-brain barrier dysfunction in L-ornithine induced acute pancreatitis in rats and the direct effect of L-ornithine on cultured brain endothelial cells

Background

In severe acute pancreatitis (AP) the CNS is affected manifesting in neurological symptoms. Earlier research from our laboratory showed blood–brain barrier (BBB) permeability elevation in a taurocholate-induced AP model. Here we aimed to further explore BBB changes in AP using a different, non-invasive in vivo model induced by l-ornithine. Our goal was also to identify whether l-ornithine, a cationic amino acid, has a direct effect on brain endothelial cells in vitro contributing to the observed BBB changes.

Methods

AP was induced in rats by the intraperitoneal administration of l-ornithine-HCl. Vessel permeability and the gene expression of the primary transporter of l-ornithine, cationic amino acid transporter-1 (Cat-1) in the brain cortex, pancreas, liver and lung were determined. Ultrastructural changes were followed by transmission electron microscopy. The direct effect of l-ornithine was tested on primary rat brain endothelial cells and a triple co-culture model of the BBB. Viability and barrier integrity, including permeability and TEER, nitrogen monoxide (NO) and reactive oxygen species (ROS) production and NF-κB translocation were measured. Fluorescent staining for claudin-5, occludin, ZO-1, β-catenin, cell adhesion molecules Icam-1 and Vcam-1 and mitochondria was performed. Cell surface charge was measured by laser Doppler velocimetry.

Results

In the l-ornithine-induced AP model vessel permeability for fluorescein and Cat-1 expression levels were elevated in the brain cortex and pancreas. On the ultrastructural level surface glycocalyx and mitochondrial damage, tight junction and basal membrane alterations, and glial edema were observed. l-ornithine decreased cell impedance and elevated the BBB model permeability in vitro. Discontinuity in the surface glycocalyx labeling and immunostaining of junctional proteins, cytoplasmic redistribution of ZO-1 and β-catenin, and elevation of Vcam-1 expression were measured. ROS production was increased and mitochondrial network was damaged without NF-κB, NO production or mitochondrial membrane potential alterations. Similar ultrastructural changes were seen in l-ornithine treated brain endothelial cells as in vivo. The basal negative zeta potential of brain endothelial cells became more positive after l-ornithine treatment.

Conclusion

We demonstrated BBB damage in the l-ornithine-induced rat AP model suggesting a general, AP model independent effect. l-ornithine induced oxidative stress, decreased barrier integrity and altered BBB morphology in a culture BBB model. These data suggest a direct effect of the cationic l-ornithine on brain endothelium. Endothelial surface glycocalyx injury was revealed both in vivo and in vitro, as an additional novel component of the BBB-related pathological changes in AP.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-022-00308-0.

Effects of Snake-Derived Phospholipase A2 Inhibitors on Acute Pancreatitis: In vitro and in vivo Characterization

Objective

We aimed to investigate the effects of snake-derived phospholipase A2 inhibitor (PLA2) from Sinonatrix percarinata and Bungarus multicinctus on acute pancreatitis in vivo and in vitro and assess the mechanisms.

Methods

The levels of platelet-activating factor (PAF) and tumor necrosis factor (TNF)-α were detected by ELISA, and the characteristics of autophagy were detected by transmission electron microscopy and Western blotting (LC3, p62, and ATG5).

Results

In vitro experiments showed that PLA2 treatment caused obvious formation of autophagic bodies. By contrast, Sinonatrix and Bungarus peptides reduced the number of autophagic bodies. The concentrations of PAF and TNF-α, and the expressions of p62, autophagy-related 5 (ATG5), and microtubule-associated protein 1A/1B-light chain 3 (LC3)II/LC3I in the PLA2-treated group were significantly higher than in the control group (P<0.05). The concentrations of PAF and TNF-α, and the expressions of p62, ATG5, and LC3II/LC3I in the Sinonatrix or Bungarus peptide treatment groups were significantly lower than in the PLA2-treated cells (P<0.05). In the pancreatic tissue, autophagic bodies were observed in the model group; autophagic bodies were remarkably reduced in Sinonatrix or Bungarus peptide-treated groups compared with the model group. In vivo experiments also showed that the levels of PAF and TNF-α, and the expressions of p62, ATG5, and LC3II/LC3I were significantly higher in the model group than in the control group (P<0.05). The levels of PAF and TNF-α in the model group, and the expressions of p62, ATG5, and LC3II/LC3I in Sinonatrix or Bungarus peptide-treated groups were significantly lower than in the model group (P<0.05).

Conclusion

Sinonatrix or Bungarus peptide could ameliorate the features of acute pancreatitis, likely through regulating autophagy.

Reductions in anti-inflammatory gut bacteria are associated with depression in a sample of young adults

We assessed the gut microbiota of 90 American young adults, comparing 43 participants with major depressive disorder (MDD) and 47 healthy controls, and found that the MDD subjects had significantly different gut microbiota compared to the healthy controls at multiple taxonomic levels. At the phylum level, participants with MDD had lower levels of Firmicutes and higher levels of Bacteroidetes, with similar trends in the at the class (Clostridia and Bacteroidia) and order (Clostridiales and Bacteroidales) levels. At the genus level, the MDD group had lower levels of Faecalibacterium and other related members of the family Ruminococcaceae, which was also reduced relative to healthy controls. Additionally, the class Gammaproteobacteria and genus Flavonifractor were enriched in participants with MDD. Accordingly, predicted functional differences between the two groups include a reduced abundance of short-chain fatty acid production pathways in the MDD group. We also demonstrated that the magnitude of taxonomic changes was associated with the severity of depressive symptoms in many cases, and that most changes were present regardless of whether depressed participants were taking psychotropic medications. Overall, our results support a link between MDD and lower levels of anti-inflammatory, butyrate-producing bacteria, and may support a connection between the gut microbiota and the chronic, low-grade inflammation often observed in MDD patients.

Regulation of the Blood-Brain Barrier by Circadian Rhythms and Sleep

The blood-brain barrier (BBB) is an evolutionarily conserved, structural, and functional separation between circulating blood and the central nervous system (CNS). By controlling permeability into and out of the nervous system, the BBB has a critical role in the precise regulation of neural processes. Here, we review recent studies demonstrating that permeability at the BBB is dynamically controlled by circadian rhythms and sleep. An endogenous circadian rhythm in the BBB controls transporter function, regulating permeability across the BBB. In addition, sleep promotes the clearance of metabolites along the BBB, as well as endocytosis across the BBB. Finally, we highlight the implications of this regulation for diseases, including epilepsy.

Pretreatment Cancer-Related Cognitive Impairment-Mechanisms and Outlook

Cognitive changes are common in patients with active cancer and during its remission. This has largely been blamed on therapy-related toxicities and diagnosis-related stress, with little attention paid to the biological impact of cancer itself. A plethora of clinical studies demonstrates that cancer patients experience cognitive impairment during and after treatment. However, recent studies show that a significant portion of patients with non-central nervous system (CNS) tumors experience cognitive decline prior to treatment, suggesting a role for tumor-derived factors in modulating cognition and behavior. Cancer-related cognitive impairment (CRCI) negatively impacts a patient’s quality of life, reduces occupational and social functioning, and increases morbidity and mortality. Furthermore, patients with cancer cachexia frequently experience a stark neurocognitive decline, suggesting peripheral tumors exert an enduring toll on the brain during this chronic paraneoplastic syndrome. However, the scarcity of research on cognitive impairment in non-CNS cancers makes it difficult to isolate psychosocial, genetic, behavioral, and pathophysiological factors in CRCI. Furthermore, clinical models of CRCI are frequently confounded by complicated drug regimens that inherently affect neurocognitive processes. The severity of CRCI varies considerably amongst patients and highlights its multifactorial nature. Untangling the biological aspects of CRCI from genetic, psychosocial, and behavioral factors is non-trivial, yet vital in understanding the pathogenesis of CRCI and discovering means for therapeutic intervention. Recent evidence demonstrating the ability of peripheral tumors to alter CNS pathways in murine models is compelling, and it allows researchers to isolate the underlying biological mechanisms from the confounding psychosocial stressors found in the clinic. This review summarizes the state of the science of CRCI independent of treatment and focuses on biological mechanisms in which peripheral cancers modulate the CNS.

Impact of Cachexia and Opioid Analgesic Cotreatment on Pregabalin Pharmacokinetics and Central Nervous System Symptoms in Cancer Patients

BACKGROUND

Patients with cancer receiving pregabalin potentially have a high incidence of central nervous system (CNS) symptoms. The purpose of this study was to explore clinical factors influencing the incidence of CNS symptoms, including plasma pregabalin exposure, cancer cachexia, and opioid analgesic cotreatment.

METHODS

Sixty-eight patients with cancer receiving twice-daily pregabalin were enrolled. Plasma concentrations of pregabalin, clinical laboratory data, opioid analgesic cotreatment, and the Glasgow Prognostic Score, which is an inflammation-based cachexia score, were considered as clinical factors. The incidence of CNS symptoms was collected from the patients' medical records. The predose plasma concentrations of pregabalin at steady state were determined by ultra-high-performance liquid chromatography.

RESULTS

The steady-state trough plasma pregabalin concentrations showed a large variability with an interquartile range of 0.43-1.2 mg/L per mg/kg and were negatively correlated with an estimated glomerular filtration rate (eGFR). C-reactive protein (standardized partial regression coefficient, β = 0.31) and opioid analgesic cotreatment (β = 0.24) were also identified in addition to eGFR (β = -0.60) in the multiple regression analysis. The incidence of CNS symptoms was significantly increased with opioid analgesic cotreatment and a higher Glasgow Prognostic Score but not with the absolute value of plasma pregabalin concentrations, eGFR, or other clinical laboratory data.

CONCLUSIONS

In patients with cancer, steady-state trough plasma pregabalin concentrations were altered with renal function, systemic inflammation, and opioid analgesic cotreatment. However, a higher incidence of CNS symptoms observed in patients with cancer on pregabalin was more related to cachexia and opioid analgesic cotreatment than to altered pregabalin concentrations.

Recombinant rabies virus expressing interleukin-6 enhances the immune response in mouse brain

Rabies, which is caused by the rabies virus (RABV), is an ancient zoonosis that has a high mortality rate. Previous studies have indicated that recombinant RABV expressing canine interleukin-6 (rHEP-CaIL6), induced more virus-neutralizing antibodies than parental RABV in mice following intramuscular immunization. To investigate the immune response induced in the CNS by rHEP-CaIL6 after intranasal or intracranial administration in mice, the permeability of the blood-brain barrier (BBB), the infiltration of CD3 T cells, and innate immune response-related effector molecules in the CNS were examined. It was observed that infection of rHEP-CaIL6 led to enhanced BBB permeability following intranasal infection. More CD3 T cells infiltrated into the central nervous system (CNS) in mice infected with rHEP-CaIL6 than in those infected with the HEP-Flury strain. Furthermore, rHEP-CaIL6 induced an increased expression of innate immune response-related effector molecules, compared with the parental HEP-Flury strain, within the CNS. Taken together, these findings suggest that rHEP-CaIL6 induced stronger immune responses in mice brains, which is more beneficial for virus clearance. These results may also partly illustrate the role of IL6 in RABV infection.

The yin/yang of inflammatory status: Blood-brain barrier regulation during sleep

Sleep loss induces a low-grade inflammatory status characterized by a subtle but sustained increase of pro-inflammatory mediators, which are key regulators of blood-brain barrier function. To investigate the influence of inflammatory status on blood-brain barrier dysfunction induced by sleep restriction we performed an experiment using two strains of mice with different immunological backgrounds, C57BL/6 mice that have a predominant pro-inflammatory response and BALB/c mice that have a predominant anti-inflammatory response. Mice were sleep-restricted during 10 days using the flowerpot technique during 20 h per day with 4 h of daily sleep opportunity. The systemic inflammatory status, blood-brain barrier permeability, and the hippocampal expression of neuroinflammatory markers were characterized at the 10th day. Serum levels of TNF and IFN-γ increased in sleep-restricted C57BL/6 but not in BALB/c mice; no changes in other cytokines were found. Sleep restriction increased blood-brain barrier permeability in C57BL/6 strain but not in BALB/c. The hippocampus of sleep-restricted C57BL/6 mice exhibited an increase in the expression of the neuroinflammatory markers Iba-1, A_2A adenosine receptor, and MMP-9; meanwhile in sleep-restricted BALB/c mice the expression of this markers was lesser than the control group. These data suggest that cytokines may be playing a key role in modulating blood-brain barrier function during sleep restriction, and probably the effects are related to Iba-1, MMP-9 and A_2A adenosine receptor overexpression.

Interleukin-10 attenuates impairment of the blood-brain barrier in a severe acute pancreatitis rat model

Background

Impairment of the blood-brain barrier (BBB) in severe acute pancreatitis (SAP) could result in life-threatening pancreatic encephalopathy. Interleukin-10 (IL-10) is a classical cytokine that is well-known for its strong immunoregulatory and anti-inflammatory abilities. However, whether and how IL-10 protects the BBB in SAP are still unclear.

Methods

This study includes in vivo experiments using a SAP rat model and in vitro experiments using an in vitro BBB model consisting of a monolayer of brain microvascular endothelial cells (BMECs). The study groups are divided into the control, SAP (in vivo)/TNF-α (in vitro), IL-10 treatment, IL-10 + signal transducer and activator of transcription 3 (STAT3) inhibitor S3I-201 treatment groups. Pancreatic pathological scores, serum amylase, serum TNF-α levels and BBB permeability by Evan’s blue assay in SAP rat models were evaluated. BMEC apoptosis in SAP rats or induced by TNF-αin vitro was detected by terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) and flow cytometry, separately. Expression levels of claudin-5 and proteins involved in the STAT3 signaling pathway were measured by Western blotting. Location and changes of junctional structure of claudin-5 on BMECs were assessed by immunohistochemistry and immunofluorescence.

Results

In vivo, IL-10 alleviated the severity of inflammation, attenuated the increased BBB permeability in SAP rat models by reducing BMEC apoptosis via the STAT3 pathway and ameliorated the down-regulation of claudin-5 expression in BMECs; in vitro, IL-10 improved BBB integrity against TNF-α by attenuating BMEC apoptosis via the STAT3 pathway, the impairment of tight junction structure and the down-regulation of claudin-5 expression in BMECs.

Conclusions

IL-10 improves BBB properties in SAP by attenuating the down-regulation of claudin-5 expression and the impairment of tight junctions and by STAT3 pathway-mediated anti-apoptotic effects on BMECs.

Pharmacokinetics and pharmacodynamics of Da-Cheng-Qi decoction in the liver of rats with severe acute pancreatitis

AIM

To explore the pharmacokinetics and pharmacodynamics of Da-Cheng-Qi decoction (DCQD) in the liver of rats with severe acute pancreatitis (SAP) based on an herbal recipe tissue pharmacology hypothesis.

METHODS

Healthy male Sprague-Dawley rats were randomly divided into a sham operation group (SOG); a model group (MG); and low-, median- and high-dose treatment groups (LDG, MDG, and HDG, respectively). Different dosages (6, 12 and 24 g/kg for the LDG, MDG, and HDG, respectively) of DCQD were administered to the rats with SAP. The tissue concentrations of aloe-emodin, rhein, emodin, chrysophanol, honokiol, rheo chrysophanol, magnolol, hesperidin, naringenin and naringin in the liver of the treated rats were detected by high-performance liquid chromatography tandem mass spectrometry. Alanine transaminase (ALT) and aspartate transaminase (AST) in serum, inflammatory mediators in the liver and pathological scores were evaluated.

RESULTS

The major components of DCQD were detected in the liver, and their concentrations increased dose-dependently. The high dose of DCQD showed a maximal effect in ameliorating the pathological damages, decreasing the pro-inflammatory mediators tumor necrosis factor-α and interleukin (IL)-6 and increasing anti-inflammatory mediators IL-4 and IL-10 in the liver. The pathological scores in the pancreas for the MG were significantly higher than those for the SOG (P < 0.05). DCQD could reduce the pathological scores in the pancreas and liver of the rats with SAP, especially in the HDG. Compared to the SOG, the ALT and AST levels in serum were higher in the MG (P < 0.05), while there was no statistical difference in the MG and HDG.

CONCLUSION

DCQD could alleviate liver damage by altering the inflammatory response in rats with SAP based on the liver distribution of its components.

Blood-Brain Barrier Disruption Induced by Chronic Sleep Loss: Low-Grade Inflammation May Be the Link

Sleep is a vital phenomenon related to immunomodulation at the central and peripheral level. Sleep deficient in duration and/or quality is a common problem in the modern society and is considered a risk factor to develop neurodegenerative diseases. Sleep loss in rodents induces blood-brain barrier disruption and the underlying mechanism is still unknown. Several reports indicate that sleep loss induces a systemic low-grade inflammation characterized by the release of several molecules, such as cytokines, chemokines, and acute-phase proteins; all of them may promote changes in cellular components of the blood-brain barrier, particularly on brain endothelial cells. In the present review we discuss the role of inflammatory mediators that increase during sleep loss and their association with general disturbances in peripheral endothelium and epithelium and how those inflammatory mediators may alter the blood-brain barrier. Finally, this manuscript proposes a hypothetical mechanism by which sleep loss may induce blood-brain barrier disruption, emphasizing the regulatory effect of inflammatory molecules on tight junction proteins.

Systemic and localized extra-central nervous system bacterial infections and the risk of dementia among US veterans: A retrospective cohort study

INTRODUCTION

Emerging evidence indicates associations between extra-central nervous system (CNS) bacterial infections and an increased risk for dementia; however, epidemiological evidence is still very limited.

METHODS

This study involved a retrospective cohort of a national sample of US veterans (N = 417,172) aged ≥56 years. Extended Cox proportional hazard models adjusted for demographic characteristics and medical and psychiatric comorbidities determined the associations between systemic and localized extra-CNS bacterial infections occurring >2 years before the initial dementia diagnosis and the risk for dementia.

RESULTS

Exposure to any extra-CNS bacterial infection was associated with a significantly increased risk for dementia (hazard ratio [HR] = 1.20 [95% confidence interval = 1.16-1.24]). Independently, septicemia (HR = 1.39 [1.16-1.66]), bacteremia (HR = 1.22 [1.00-1.49]), osteomyelitis (HR = 1.20 [1.06-1.37]), pneumonia (HR = 1.10 [1.02-1.19]), urinary tract infections (HR = 1.13 [1.08-1.18]), and cellulitis (HR = 1.14 [1.09-1.20]) were associated with a significantly increased risk for dementia.

DISCUSSION

Both systemic and localized extra-CNS bacterial infections are associated with an increased risk for developing dementia.

Posterior Reversible Encephalopathy Syndrome Complicating Traumatic Pancreatitis: A Pediatric Case Report

We are reporting a case of posterior reversible encephalopathy syndrome (PRES) developed in an unusual clinical scenario without the presence of the most described symptoms. PRES is a neurological and radiological syndrome described in many different clinical conditions. In children it has been mostly reported in association with hematological and renal disorders.Our patient was a 15 years old boy, admitted to our intensive care unit for pancreatitis after blunt abdominal trauma.During the stay in the intensive care unit, he underwent multiple abdominal surgical interventions for pancreatitis complications. He had a difficult management of analgesia and sedation, being often agitated with high arterial pressure, and he developed a bacterial peritonitis. After 29 days his neurological conditions abruptly worsened with neuroimaging findings consistent with PRES. His clinical conditions progressively improved after sedation and arterial pressure control.He was discharged at home with complete resolution of the neurological and imaging signs 2 months later.The pathophysiology of PRES is controversial and involves disordered autoregulation ascribable to hypertension and endothelial dysfunction. In this case both hypertension and endothelial activation, triggered by sepsis and pancreatitis, could represent the culprits of PRES onset. Even if there is no specific treatment for this condition, a diagnosis is mandatory to start antihypertensive and supportive treatment. We are therefore suggesting to consider PRES in the differential diagnosis of a neurological deterioration preceded by hypertension and/or septic state, even without other "typical" clinical features.

Heterogeneity of the blood-brain barrier

The brain microvascular network is comprised of capillaries, arterioles and venules, all of which retain - although to a different extent - blood-brain barrier (BBB) properties. Capillaries constitute the largest and tightest microvasculature. In contrast, venules have a looser junctional arrangement, while arterioles have a lower expression of P-gp. Development and maintenance of the BBB depends on the interaction of cerebral endothelial cells with pericytes and astrocytes, which are all heterogeneous in different regions of the central nervous system. At the level of circumventricular organs microvessels are permeable, containing fenestrations and discontinuous tight junctions. In addition, the blood-spinal cord barrier - where the number of pericytes is lower and expression of junctional proteins is reduced - is also more permeable than the BBB. However, much less is known about the cellular, molecular and functional differences among other regions of the brain. This review summarizes our current knowledge on the heterogeneity of the brain microvasculature.

Western diets induce blood-brain barrier leakage and alter spatial strategies in rats

Western diet (WD) intake induces obesity and metabolic dysfunction. The present study examined the effects of WD on hippocampal-dependent cognitive functioning and blood-brain barrier (BBB) permeability as a function of exposure duration, obesity phenotype, and peripheral markers of energy regulation. The use of hippocampal-dependent "place" or hippocampal-independent "response" strategies in a Y maze was assessed in male rats following 10, 40, and 90 days of WD exposure in diet-induced obese (DIO) rats, in diet resistant (DR) rats that are relatively insensitive to the obesogenic properties of WD, and in chow-fed controls. Insulin, glucose, and BBB permeability throughout several loci in the hippocampus, striatum, and cerebellum were evaluated in relation to duration of WD exposure, obesity phenotype, and type of strategy used. DIO rats had increased body weight and adiposity throughout the study, and elevated 10-day glucose and 90-day insulin levels. Throughout the study, chow-fed and DR rats reliably relied on a place strategy. DIO rats, in contrast, favored a response strategy at the 10- and 90-day time points. BBB leakage was observed in the dorsal striatum and multiple subregions of the hippocampus of DIO, but not DR or chow-fed rats. Increased ventral hippocampal BBB permeability and blood glucose levels were associated with reduced place strategy use. These data indicate that WD-induced BBB leakage is dependent on duration of diet exposure as well as obesity phenotype, and implicates BBB leakage and impaired glucoregulation in behavioral strategy and cognitive performance.

Osthole confers neuroprotection against cortical stab wound injury and attenuates secondary brain injury

Background

Neuroendoscopy is an innovative technique for neurosurgery that can nonetheless result in traumatic brain injury. The accompanying neuroinflammation may lead to secondary tissue damage, which is the major cause of delayed neuronal death after surgery. The present study investigated the capacity of osthole to prevent secondary brain injury and the underlying mechanism of action in a mouse model of stab wound injury.

Methods

A mouse model of cortical stab wound injury was established by inserting a needle into the cerebral cortex for 20 min to mimic neuroendoscopy. Mice received an intraperitoneal injection of osthole 30 min after surgery and continued for 14 days. Neurological severity was evaluated 12 h and up to 21 days after the trauma. Brains were collected 3–21 days post-injury for histological analysis, immunocytochemistry, quantitative real-time PCR, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and enzyme-linked immunosorbent assays.

Results

Neurological function improved in mice treated with osthole and was accompanied by reduced brain water content and accelerated wound closure relative to untreated mice. Osthole treatment reduced the number of macrophages/microglia and peripheral infiltrating of neutrophils and lowered the level of the proinflammatory cytokines interleukin-6 and tumor necrosis factor α in the lesioned cortex. Osthole-treated mice had fewer TUNEL+ apoptotic neurons surrounding the lesion than controls, indicating increased neuronal survival.

Conclusions

Osthole reduced secondary brain damage by suppressing inflammation and apoptosis in a mouse model of stab wound injury. These results suggest a new strategy for promoting neuronal survival and function after neurosurgery to improve long-term patient outcome.

Indoleamine 2,3-dioxygenase is upregulated in the brain of rats with acute pancreatitis

BACKGROUND

Acute pancreatitis (AP) has an effect on both inflammatory/autoimmune processes and psychological states, but the pathophysiological causes of pancreatic encephalopathy in the brain are unclear. We hypothesized that the peripheral immune/inflammatory response during AP can affect indolamine 2,3-dioxygenase (IDO) expression and serotonin content in the brain.

METHODS

About 210 male Sprague Dawley rats were randomly divided into five groups: control (0 h) and 6 h, 24 h, 48 h and 72 h experimental groups. Acute pancreatitis was induced by an injection of a sodium taurocholate solution via a cannulated bile-pancreatic duct. We measured the plasma TNF-α and IL-6 levels; serotonin, 5-HIAA and the protein concentration levels of IDO and monoamine oxidase A (MAO-A) were evaluated in the striatum, hippocampus and left prefrontal cortex.

RESULTS

The IL-6 and the TNF-α levels increased in the 24 h, 48 h and 72 h groups. The IDO concentrations of both the 72 h group in the hippocampus and 48 h, 72 h groups in the prefrontal cortex increased; in the corpus striatum, the IDO concentrations fluctuated without statistical significance. The MAO-A protein concentration of the 6 h and 24 h groups decreased in the striatum, hippocampus and prefrontal cortex. There were no statistically significant differences found in the serotonin and 5-HIAA concentrations.

CONCLUSIONS

During the process of AP, cytokines, such as IL-6 and TNF-α, may play a role in activation of neuronal pathways utilizing the metabolic enzyme IDO, which may play an important role in determining the mental symptomatology accompanying AP.

A case of posterior reversible encephalopathy syndrome associated with acute pancreatitis and chronic alcoholism

Posterior reversible encephalopathy syndrome (PRES) is known to be caused by a variety of clinical disorders. The authors encountered a case of PRES associated with acute pancreatitis and chronic alcoholism. A 49-year-old man presented with altered mental status. Magnetic resonance imaging (MRI) displayed vasogenic edema at the bilateral posterior temporal and parieto-occipital lobes and cerebellum. Laboratory tests and abdominal computed tomography (CT) revealed acute pancreatitis. The patient recovered completely, and follow-up brain MRI and abdominal CT exhibited resolution of the previous lesions. We suggest that acute pancreatitis might be an etiology of PRES.

Co-grafting of neural stem cells with olfactory en sheathing cells promotes neuronal restoration in traumatic brain injury with an anti-inflammatory mechanism

BACKGROUND

We sought to investigate the effects of co-grafting neural stem cells (NSCs) with olfactory ensheathing cells (OECs) on neurological behavior in rats subjected to traumatic brain injury (TBI) and explore underlying molecular mechanisms.

METHODS

TBI was established by percussion device made through a weight drop (50 g) from a 30 cm height. Cultured NSCs and OECs isolated from rats were labeled by Hoechst 33342 (blue) and chloromethyl-benzamidodialkyl carbocyanine (CM-Dil) (red), respectively. Then, NSCs and/or OECs, separately or combined, were transplanted into the area surrounding the injury site. Fourteen days after transplantation, neurological severity score (NSS) were recorded. The brain tissue was harvested and processed for immunocytochemistry, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and reverse transcription-polymerase chain reaction (RT-PCR).

RESULTS

Significant neurological function improvement was observed in the three transplant groups, compared to the TBI group, and co-transplantation gave rise to the best improvement. Morphological evaluation showed that the number of neurons in cortex from combination implantation was more than for other groups (P <0.05); conversely, the number of apoptotic cells showed a significant decrease by TUNEL staining. Transplanted NSCs and OECs could survive and migrate in the brain, and the number of neurons differentiating from NSCs in the co-transplantation group was significantly greater than in the NSCs group. At the molecular level, the expressions of IL-6 and BAD in the co-graft group were found to be down regulated significantly, when compared to either the NSC or OEC alone groups.

CONCLUSION

The present study demonstrates for the first time the optimal effects of co-grafting NSCs and OECs as a new strategy for the treatment of TBI via an anti-inflammation mechanism.

Status epilepticus induces vasogenic edema via tumor necrosis factor-α/ endothelin-1-mediated two different pathways

Status epilepticus (SE) induces vasogenic edema in the piriform cortex with disruptions of the blood-brain barrier (BBB). However, the mechanisms of vasogenic edema formation following SE are still unknown. Here we investigated the endothelin B (ET_B) receptor-mediated pathway of SE-induced vasogenic edema. Following SE, the release of tumor necrosis factor-α (TNF-α) stimulated endothelin-1 (ET-1) release and expression in neurons and endothelial cells. In addition, TNF-α-induced ET-1 increased BBB permeability via ET_B receptor-mediated endothelial nitric oxide synthase (eNOS) activation in endothelial cells. ET_B receptor activation also increased intracellular reactive oxygen species by NADPH oxidase production in astrocytes. These findings suggest that SE results in BBB dysfunctions via endothelial-astroglial interactions through the TNF-α-ET-1-eNOS/NADPH oxidase pathway, and that these ET_B receptor-mediated interactions may be an effective therapeutic strategy for vasogenic edema in various neurological diseases.

TIMP-1 attenuates blood-brain barrier permeability in mice with acute liver failure

Blood-brain barrier (BBB) dysfunction in acute liver failure (ALF) results in increased BBB permeability that often precludes the patients from obtaining a life-saving liver transplantation. It remains controversial whether matrix metalloproteinase-9 (MMP-9) from the injured liver contributes to the deregulation of BBB function in ALF. We selectively upregulated a physiologic inhibitor of MMP-9 (TIMP-1) with a single intracerebroventricular injection of TIMP-1 cDNA plasmids at 48 and 72 hours, or with pegylated-TIMP-1 protein. Acute liver failure was induced with tumor necrosis factor-α and D-(+)-galactosamine in mice. Permeability of BBB was assessed with sodium fluorescein (NaF) extravasation. We found a significant increase in TIMP-1 within the central nervous system (CNS) after the administration of TIMP-1 cDNA plasmids and that increased TIMP-1 within the CNS resulted in an attenuation of BBB permeability, a reduction in activation of epidermal growth factor receptor and p38 mitogen-activated protein kinase signals, and a restoration of the tight junction protein occludin in mice with experimental ALF. Pegylated TIMP-1 provided similar protection against BBB permeability in mice with ALF. Our results provided a proof of principle that MMP-9 contributes to the BBB dysfunction in ALF and suggests a potential therapeutic role of TIMP-1 in ALF.

Species-Dependent Blood-Brain Barrier Disruption of Lipopolysaccharide: Amelioration by Colistin In Vitro and In Vivo

The aim of this study was to use in vitro and in vivo models to assess the impact of lipopolysaccharide (LPS) from two different bacterial species on blood-brain barrier (BBB) integrity and brain uptake of colistin. Following repeated administration of LPS from Pseudomonas aeruginosa, the brain-to-plasma ratio of [¹⁴C]sucrose in Swiss outbred mice was not significantly increased. Furthermore, while the brain uptake of colistin in mice increased 3-fold following administration of LPS from Salmonella enterica, LPS from P. aeruginosa had no significant effect on colistin brain uptake. This apparent species-dependent effect did not appear to correlate with differences in plasma cytokine levels, as the concentrations of tumor necrosis factor alpha and interleukin-6 following administration of each LPS were not different (P > 0.05). To clarify whether this species-specific effect of LPS was due to direct effects on the BBB, human brain capillary endothelial (hCMEC/D3) cells were treated with LPS from P. aeruginosa or S. enterica and claudin-5 expression was measured by Western blotting. S. enterica LPS significantly (P < 0.05) reduced claudin-5 expression at a concentration of 7.5 μg/ml. In contrast, P. aeruginosa LPS decreased (P < 0.05) claudin-5 expression only at the highest concentration tested (i.e., 30 μg/ml). Coadministration of therapeutic concentrations of colistin ameliorated the S. enterica LPS-induced reduction in claudin-5 expression in hCMEC/D3 cells and the perturbation in BBB function in mice. This study demonstrates that BBB disruption induced by LPS is species dependent, at least between P. aeruginosa and S. enterica, and can be ameliorated by colistin.

Acid extrusion via blood-brain barrier causes brain alkalosis and seizures after neonatal asphyxia

Birth asphyxia is often associated with a high seizure burden that is predictive of poor neurodevelopmental outcome. The mechanisms underlying birth asphyxia seizures are unknown. Using an animal model of birth asphyxia based on 6-day-old rat pups, we have recently shown that the seizure burden is linked to an increase in brain extracellular pH that consists of the recovery from the asphyxia-induced acidosis, and of a subsequent plateau level well above normal extracellular pH. In the present study, two-photon imaging of intracellular pH in neocortical neurons in vivo showed that pH changes also underwent a biphasic acid–alkaline response, resulting in an alkaline plateau level. The mean alkaline overshoot was strongly suppressed by a graded restoration of normocapnia after asphyxia. The parallel post-asphyxia increase in extra- and intracellular pH levels indicated a net loss of acid equivalents from brain tissue that was not attributable to a disruption of the blood–brain barrier, as demonstrated by a lack of increased sodium fluorescein extravasation into the brain, and by the electrophysiological characteristics of the blood–brain barrier. Indeed, electrode recordings of pH in the brain and trunk demonstrated a net efflux of acid equivalents from the brain across the blood–brain barrier, which was abolished by the Na/H exchange inhibitor, N-methyl-isobutyl amiloride. Pharmacological inhibition of Na/H exchange also suppressed the seizure activity associated with the brain-specific alkalosis. Our findings show that the post-asphyxia seizures are attributable to an enhanced Na/H exchange-dependent net extrusion of acid equivalents across the blood–brain barrier and to consequent brain alkalosis. These results suggest targeting of blood–brain barrier-mediated pH regulation as a novel approach in the prevention and therapy of neonatal seizures.

Central and extrapontine myelinolysis affecting the brain and spinal cord. An unusual presentation of pancreatic encephalopathy

Pancreatic encephalopathy refers to a gamut of neuropsychiatric symptoms complicating acute pancreatitis. Osmotic myelinolysis is a known complication of pancreatic encephalopathy. We evaluated a 58-year-old woman with pancreatic encephalopathy associated to pontine and extrapontine myelinolysis involving the brain and spinal cord. To our knowledge, this is the first clinic pathological case report of pancreatic encephalopathy involving the spinal cord.

Effect of systemic infection induced by Pseudomonas aeruginosa on the brain uptake of colistin in mice

In view of reports of colistin-induced neurotoxicity in infected patients, the aim of this study was to assess whether the integrity of the blood-brain barrier (BBB) and the brain uptake of colistin are altered in the presence of systemic Pseudomonas aeruginosa infection. Bacteremia was confirmed 8 h after intramuscular administration of P. aeruginosa ATCC 27853 to Swiss Outbred mice, at which time a single subcutaneous dose of colistin sulfate (40 mg/kg of body weight) or an intravenous dose of [(14)C]sucrose (2 μCi) was administered. Despite a substantial elevation in plasma levels of the proinflammatory cytokines tumor necrosis factor alpha, interleukin-1β, and interleukin-6 during bacterial infection, the brain uptake of colistin was similar between infected and noninfected mice with AUC(brain)/AUC(plasma) (where AUC(brain) is the area under the brain concentration-time curve and AUC(plasma) is the area under the plasma concentration-time curve) ratios of 0.023 and 0.024, respectively. Similarly, the brain-to-plasma ratios of [(14)C]sucrose were no different between infected and noninfected mice, consistent with a lack of effect of bacteremia on BBB integrity. To further correlate any relationship between BBB disruption and plasma levels of proinflammatory cytokines, BBB integrity, colistin brain uptake, and plasma proinflammatory cytokines were measured following the administration of Salmonella enterica lipopolysaccharide (LPS), an agent known to induce BBB disruption. Despite LPS inducing a 4-fold increase in colistin brain uptake and a significant (P < 0.05) 1.2-fold increase in [(14)C]sucrose BBB penetration, plasma cytokine levels were lower with LPS treatment relative to those obtained with bacterial infection with P. aeruginosa. This study demonstrates that the brain uptake of colistin is not increased in mice during P. aeruginosa-induced systemic bacteremia despite a significant increase in plasma levels of three proinflammatory cytokines.

Protective effect of low-molecular-weight heparin on pancreatic encephalopathy in severe acute pancreatic rats

BACKGROUND AND AIMS

Pancreatic encephalopathy (PE) is a severe complication and significant cause of death in patients with severe acute pancreatitis (SAP). We have reported previously that low-molecular-weight heparin (LMWH) treatment could reduce incidence of PE in SAP patients. Our objective here was to investigate the protective effect of LMWH and its mechanism on PE in SAP rats.

METHODS

SD rats were randomly divided into three groups: (1) Sham-operation (S) group, (2) SAP group, and (3) LMWH treatment (LMWH) group. LMWH was administrated 4 h after the SAP model conducted. The levels of serum amylase, myelin basic protein (MBP), tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), brain water content, occurrence of apoptosis, and pathological changes of pancreas and brain were measured at 1 day after models were set up in the SAP and S groups, and 1 day after LMWH treatment was administrated in the LMWH group.

RESULTS

(1) The levels of serum amylase, TNF-α, and IL-6 in the SAP group were increased significantly more than those in the S and LMWH groups (all P < 0.001), as were the levels of serum MBP in the SAP group compared to those in the S and LMWH groups (P < 0.01, <0.05 respectively). However, while the level of serum amylase and IL-6 in the LMWH group were significantly increased compared to those in the S group (P < 0.05, <0.001 respectively), the levels of TNF-α and MBP showed no significant difference between the LMWH and S groups (all P > 0.05). (2) The brain water content in the SAP group was significantly increased compared to the S group and LMWH group (P < 0.01, <0.05 respectively). (3) Neuronal apoptosis, demyelination, and mitochondrial vacuolation in neuronal cells were observed in the SAP group; in contrast, in the LMWH group, significantly lower rates of neuronal apoptosis, demyelination and mitochondrial edema were observed in neuronal cells.

CONCLUSIONS

The protective effect of LMWH on PE progression in SAP rats might result from inhibition of inflammatory activation and reduction of the occurrence of neuronal apoptosis.

Experimental pancreatitis results in increased blood-brain barrier permeability in rats: a potential role of MCP-1

OBJECTIVE

To measure the changes of blood-brain barrier (BBB) permeability in rats with acute pancreatitis (AP) and to investigate the role of monocyte chemoattractant protein (MCP)-1 expression in this alteration.

METHODS

Rat model of severe acute pancreatitis (SAP) and mild acute pancreatitis (MAP) was induced by pancreatic duct infusion of 5% and 0.5% sodium choleate, respectively, and a saline infusion was used in the control. The severity of AP was evaluated by a pathological score system. BBB permeability was detected by Evan's blue tracer and BBB tight junction was assessed by brain occludin expression. Immunohistochemistry and real-time polymerase chain reaction were used to detect MCP-1 expression in the brain. Nifedipine was used as the antagonist of MCP-1.

RESULTS

Compared to the control group, change of BBB permeability was more significant in SAP groups, but not in MAP groups. Occludin level decreased 12 h after SAP induction. Pathological score of SAP group was higher than that in MAP group. BBB opening was associated with pancreatic injury. Brain MCP-1 expression was detected in all the SAP groups, which was correlated with increased BBB permeability, but was not found in the control group or the MAP group. After treatment with nifedipine, brain MCP-1 level decreased and BBB function improved synchronously in SAP groups.

CONCLUSIONS

BBB permeability increased in SAP significantly and time-dependently, and was correlated with brain MCP-1 expression. Nifedipine may improve BBB function by inhibiting MCP-1 expression.

Tumor necrosis factor-α-mediated threonine 435 phosphorylation of p65 nuclear factor-κB subunit in endothelial cells induces vasogenic edema and neutrophil infiltration in the rat piriform cortex following status epilepticus

BACKGROUND

Status epilepticus (SE) induces severe vasogenic edema in the piriform cortex (PC) accompanied by neuronal and astroglial damages. To elucidate the mechanism of SE-induced vasogenic edema, we investigated the roles of tumor necrosis factor (TNF)-α in blood-brain barrier (BBB) disruption during vasogenic edema and its related events in rat epilepsy models provoked by pilocarpine-induced SE.

METHODS

SE was induced by pilocarpine in rats that were intracerebroventricularly infused with saline-, and soluble TNF p55 receptor (sTNFp55R) prior to SE induction. Thereafter, we performed Fluoro-Jade B staining and immunohistochemical studies for TNF-α and NF-κB subunits.

RESULTS

Following SE, most activated microglia showed strong TNF-α immunoreactivity. In addition, TNF p75 receptor expression was detected in endothelial cells as well as astrocytes. In addition, only p65-Thr435 phosphorylation was increased in endothelial cells accompanied by SMI-71 expression (an endothelial barrier antigen). Neutralization of TNF-α by soluble TNF p55 receptor (sTNFp55R) infusion attenuated SE-induced vasogenic edema and neuronal damages via inhibition of p65-Thr435 phosphorylation in endothelial cells. Furthermore, sTNFp55R infusion reduced SE-induced neutrophil infiltration in the PC.

CONCLUSION

These findings suggest that impairments of endothelial cell functions via TNF-α-mediated p65-Thr 485 NF-κB phosphorylation may be involved in SE-induced vasogenic edema. Subsequently, vasogenic edema results in extensive neutrophil infiltration and neuronal-astroglial loss.

Study of dexamethasone, baicalin and octreotide on brain injury of rats with severe acute pancreatitis

OBJECTIVE

To investigate the protecting effects of dexamethasone (DXM), baicalin and octreotide on brain injury of rats with severe acute pancreatitis (SAP) and explore their underlying mechanism.

METHODS

This experiment was divided into two different parts: (1) In the first part, 90 SAP rats were randomly divided into a model control group and a DXM treated group (n = 45, respectively). (2) In the second part, 135 SAP rats were randomly divided into a model control group, a baicalin treated group and an octreotide treated group (n = 45, respectively). In two different experiments, the same number of normal rats were considered as the sham-operated group (n = 45, respectively). At 3, 6 and 12 h after operation, the pathological changes in the brain were observed. The expression levels of nuclear factor-κB (NF-κB), Bax and Bcl-2 proteins were detected and apoptosis indexes were calculated, using brain tissue microarray section.

RESULTS

(1) First part: The expression levels of Bax and Bcl-2 were significantly higher in the DXM treated group than those in the model control group at different time points, while the content of NF-κB protein and pathological changes were significantly lower in the treated group than those in the model control group (P < 0.05, P < 0.01 or P < 0.001). But the apoptotic indexes of brain tissue were not significantly different at different time points (P > 0.05). (2) Second part: At all time points after operation, the expression levels of NF-κB in the brain of treated groups were, to varying degrees, significantly lower than those in the model control group while the expression levels of Bcl-2 protein in baicalin and octreotide group were significantly higher than those in model control group (P < 0.01, P < 0.01 and P < 0.05, respectively). At 12 h after operation, the expression level of Bax protein in baicalin treated group was significantly higher than those in model control group and octreotide treated group (P < 0.05 and P < 0.01, respectively).

CONCLUSIONS

Dexamethasone, baicalin and octreotide can exert protective effects against brain injury in SAP rats mainly through inhibiting the expression of NF-κB protein.

Lipopolysaccharide-enhanced transcellular transport of HIV-1 across the blood-brain barrier is mediated by luminal microvessel IL-6 and GM-CSF

Elevated levels of cytokines/chemokines contribute to increased neuroinvasion of human immunodeficiency virus type 1 (HIV-1). Previous work showed that lipopolysaccharide (LPS), which is present in the plasma of patients with HIV-1, enhanced transcellular transport of HIV-1 across the blood-brain barrier (BBB) through the activation of p38 mitogen-activated protein kinase (MAPK) signaling in brain microvascular endothelial cells (BMECs). Here, we found that LPS (100 μg/mL, 4 hr) selectively increased interleukin (IL)-6 and granulocyte-macrophage colony-stimulating factor (GM-CSF) release from BMECs. The enhancement of HIV-1 transport induced by luminal LPS was neutralized by treatment with luminal, but not with abluminal, antibodies to IL-6 and GM-CSF without affecting paracellular permeability as measured by transendothelial electrical resistance (TEER). Luminal, but not abluminal, IL-6 or GM-CSF also increased HIV-1 transport. U0126 (MAPK kinase (MEK)1/2 inhibitor) and SB203580 (p38 MAPK inhibitor) decreased the LPS-enhanced release of IL-6 and GM-CSF. These results show that p44/42 and p38 MAPK signaling pathways mediate the LPS-enhanced release of IL-6 and GM-CSF. These cytokines, in turn, act at the luminal surface of the BMEC to enhance the transcellular transport of HIV-1 independently of actions on paracellular permeability.

Effect of lower-molecular weight heparin in the prevention of pancreatic encephalopathy in the patient with severe acute pancreatitis

OBJECTIVE

To study the effect of lower-molecular weight heparin in the prevention of pancreatic encephalopathy (PE) in the patient with severe acute pancreatitis (SAP).

METHODS

Two hundred sixty-five SAP patients were randomly divided into 2 groups: (1) conventional treatment group (C group, n = 130) and (2) conventional treatment plus lower-molecular weight heparin treatment group (LT group, n = 135). The clinical parameters, laboratory parameters and computed tomographic (CT) score of pancreatic necrosis (CTSPN), incidence of PE, and mortality in the 2 groups were compared.

RESULTS

On admission, all the clinical parameters, laboratory parameters, and CTSPN in the 2 groups were not significantly different (P > 0.05). However, 1 to 2 weeks after treatment, the symptoms and signs improvement rate, the levels of blood and urine amylase, the CT score, and the Acute Physiology and Chronic Health Evaluation II score in the LT group were obviously lower than those in the C group (P < 0.05-0.01), and PE occurrence rate, mortality, and mean hospital stay in LT group were obviously lower than those in the C group (P < 0.05-0.01).

CONCLUSIONS

Lower-molecular weight heparin can enhance the effect of conventional treatment of SAP and can markedly decrease the PE incidence and improve the survival rate of SAP. Lower-molecular weight heparin is a simple, safe, less expensive, and effective method for treatment of SAP. It can be used in every hospital.

Combined perioperative plasma endoglin and VEGF--a assessment in colorectal cancer patients

Colorectal cancer growth and spread is absolutely dependent on angiogenesis with vascular endothelial growth factor (VEGF) being the most important cytokine involved in the process. Endoglin, a membrane co-receptor for TGF-beta, has recently emerged as a sensitive index of cancer stage. There is now sufficient evidence indicating that microvessel density assessed by endoglin-immunostaining can correlate with stage of colorectal cancer and patient survival. An association of a soluble form of endoglin with lymph node and distant metastases has recently been reported in two studies. Both of them used local elaborated immunoassays for endoglin assessment. The aim of our study was to determine the efficacy of plasma endoglin, assessed using a commercial kit, as a marker of tumor spread and distant metastases in colorectal cancer patients. We studied 48 colorectal cancer patients, compared with 22 healthy subjects, using ELISA. We observed that colorectal cancer patients had increased plasma VEGF-A, but not endoglin levels. However, we found an association of plasma endoglin with the stage of malignancy. Endoglin levels were increased in metastasis-positive patients when compared to both metastasis-negative patients and healthy volunteers. Plasma endoglin correlated with VEGF-A, CEA and CA19.9. Endoglin assessment in plasma does not seem useful as a maker of colorectal cancer. Our observations indicate however that it might be helpful in selecting patients with metastatic disease.

Influenza-associated central nervous system dysfunction: a literature review

CONTEXT

Influenza is a viral pathogen that imposes an under-recognized burden of central nervous system (CNS) disease.

OBJECTIVE

To describe the epidemiology, clinical features and etiology of the CNS disease entities associated with influenza.

DATA SOURCES

English-language publications from MEDLINE.

DATA EXTRACTION

Articles were identified using "influenza, human"[Mesh] AND "nervous system diseases"[Mesh] and screened for inclusion based on relevance and scientific rigor.

RESULTS

Febrile seizure is the most frequently encountered influenza-associated CNS complication, with one in five children hospitalized with influenza experiencing one or more events. In most instances, symptoms resolve without neurological sequelae, although the risk for subsequent afebrile seizure may be increased. Influenza-associated encephalitis/encephalopathy is a less common but potentially more serious complication that is widely reported in Japanese populations, although cases from other East Asian countries, North America, and Europe have been described. Clinical manifestations are diverse, and typically involve febrile seizures and abnormal behaviors in mild cases, with rapid evolution through decreased consciousness to coma in severe forms. In cases of serious disease, the prognosis is often poor, with outcomes including death or severe neurological sequelae. Influenza is also a known trigger for a number of rarely encountered, yet often serious, CNS diseases, including the encephalopathic condition of Reye's syndrome, the peripheral neuropathy known as Guillain-Barré syndrome, and the lesser known complaints of Kleine-Levin syndrome and post-encephalitic Parkinson's disease.

CONCLUSIONS

Influenza imposes a sizeable burden of CNS disease. Increased awareness and monitoring of CNS function is indicated, especially in infants and young children.

Pentosan polysulfate protects brain endothelial cells against bacterial lipopolysaccharide-induced damages

Peripheral inflammation can aggravate local brain inflammation and neuronal death. The blood-brain barrier (BBB) is a key player in the event. On a relevant in vitro model of primary rat brain endothelial cells co-cultured with primary rat astroglia cells lipopolysaccharide (LPS)-induced changes in several BBB functions have been investigated. LPS-treatment resulted in a dose- and time-dependent decrease in the integrity of endothelial monolayers: transendothelial electrical resistance dropped, while flux of permeability markers fluorescein and albumin significantly increased. Immunostaining for junctional proteins ZO-1, claudin-5 and beta-catenin was significantly weaker in LPS-treated endothelial cells than in control monolayers. LPS also reduced the intensity and changed the pattern of ZO-1 immunostaining in freshly isolated rat brain microvessels. The activity of P-glycoprotein, an important efflux pump at the BBB, was also inhibited by LPS. At the same time production of reactive oxygen species and nitric oxide was increased in brain endothelial cells treated with LPS. Pentosan polysulfate, a polyanionic polysaccharide could reduce the deleterious effects of LPS on BBB permeability, and P-glycoprotein activity. LPS-stimulated increase in the production of reactive oxygen species and nitric oxide was also decreased by pentosan treatment. The protective effect of pentosan for brain endothelium can be of therapeutical significance in bacterial infections affecting the BBB.

Pathophysiology of the blood-brain barrier: animal models and methods

The specialized cerebral microvascular endothelium interacts with the cellular milieu of the brain and extracellular matrix to form a neurovascular unit, one aspect of which is a regulated interface between the blood and central nervous system (CNS). The concept of this blood-brain barrier (BBB) as a dynamically regulated system rather than a static barrier has wide-ranging implications for pathophysiology of the CNS. While in vitro models of the BBB are useful for screening drugs targeted to the CNS and indispensable for studies of cerebral endothelial cell biology, the complex interactions of the neurovascular unit make animal-based models and methods essential tools for understanding the pathophysiology of the BBB. BBB dysfunction is a complication of neurodegenerative disease and brain injury. Studies on animal models have shown that diseases of the periphery, such as diabetes and inflammatory pain, have deleterious effects on the BBB which may contribute to neurological complications associated with these conditions. Furthermore, genetic and/or epigenetic abnormalities in constituents of the BBB may be significant contributing factors in disease etiology. Research that approaches the BBB as a dynamic system integrated with both the CNS and the periphery is therefore critical to understanding and treating diseases of the CNS. Herein, we review various methodological approaches used to study BBB function in the context of disease. These include measurement of transport between blood and brain, imaging-based technologies, and genomic/proteomic approaches.

Dexamethasone mediates protection against acute pancreatitis via upregulation of pancreatitis-associated proteins

AIM

To examine the influence of dexamethasone on pancreatitis-associated protein (PAP) gene expression using both in vitro and in vivo models of acute pancreatitis and to study how PAP gene expression correlates with severity of pancreatitis.

METHODS

In vitro, IL-6 stimulated pancreas acinar AR42J cells were cultured with increasing concentrations of dexamethasone and assayed for PAP expression (RT-PCR). In vivo, pancreatitis was induced in rats by retrograde injection of 40 g/L taurocholate into the pancreatic duct. Animals were pretreated with dexamethasone (2 mg/kg) daily or saline for 4 d. Pancreata and serum were harvested after 24 h and gene expression levels of PAP I, II and III were measured by RT-PCR. Severity of pancreatitis was based on serum amylase, pancreatic wet weight, and histopathological score.

RESULTS

In vitro, dexamethasone and IL-6 induced a marked transcription of PAP I, II and III genes in AR42J cells at 24 h (P < 0.05 for all comparisons). In vivo, pancreas mRNA levels of PAP I, II or III increased by 2.6-fold, 1.9-fold, and 1.3-fold respectively after dexamethasone treatment, compared with saline treated animals. Serum amylase levels and edema were significantly lower in the dexamethasone group compared with the saline group. Histopathologic evaluation revealed less inflammation and necrosis in pancreata obtained from dexamethasone treated animals (P < 0.05).

CONCLUSION

Dexamethasone significantly decreases the severity of pancreatitis. The protective mechanism of dexamethasone may be via upregulating PAP gene expression during injury.

Regional differences in blood-brain barrier permeability changes and inflammation in the apathogenic clearance of virus from the central nervous system

The loss of blood-brain barrier (BBB) integrity in CNS inflammatory responses triggered by infection and autoimmunity has generally been associated with the development of neurological signs. In the present study, we demonstrate that the clearance of the attenuated rabies virus CVS-F3 from the CNS is an exception; increased BBB permeability and CNS inflammation occurs in the absence of neurological sequelae. We speculate that regionalization of the CNS inflammatory response contributes to its lack of pathogenicity. Despite virus replication and the expression of several chemokines and IL-6 in both regions being similar, the up-regulation of MIP-1beta, TNF-alpha, IFN-gamma, and ICAM-1 and the loss of BBB integrity was more extensive in the cerebellum than in the cerebral cortex. The accumulation of CD4- and CD19-positive cells was higher in the cerebellum than the cerebral cortex. Elevated CD19 levels were paralleled by kappa-L chain expression levels. The timing of BBB permeability changes, kappa-L chain expression in CNS tissues, and Ab production in the periphery suggest that the in situ production of virus-neutralizing Ab may be more important in virus clearance than the infiltration of circulating Ab. The data indicate that, with the possible exception of CD8 T cells, the effectors of rabies virus clearance are more commonly targeted to the cerebellum. This is likely the result of differences in the capacity of the tissues of the cerebellum and cerebral cortex to mediate the events required for BBB permeability changes and cell invasion during virus infection.

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Disruption of the blood-brain barrier during TNBS colitis

Well-documented central nervous system changes during colitis suggest possible alterations of blood-brain barrier (BBB) permeability, yet the integrity of the BBB has not been fully evaluated in experimental colitis. Our aim was to investigate whether trinitrobenzene sulphonic acid (TNBS) colitis was associated with an increase in the permeability of the BBB. Sprague-Dawley rats were given an intracolonic injection of saline or TNBS and studied 1, 2, 3, 7 and 21 days after treatment. The extravasation of endogenous immunoglobulin G, a large molecule, was not altered at any time after TNBS treatment. In contrast, significant increases in the BBB leakage of sodium fluorescein, a much smaller molecule, were observed 1 and 2 days after the induction of colitis, in and around the circumventricular organs; the organum vasculosum of the lamina terminalis, subfornical organ and median eminence of the hypothalamus. TNBS-treated rats also exhibited sodium fluorescein leakage in focal areas in the brain parenchyma. The expression of endothelial barrier antigen, a protein associated with the BBB, was reduced about 60% 48 h after the induction of colitis. This returned to control values by 3 weeks, when colitis had largely subsided. In conclusion, experimental colitis transiently increased permeability of the brain to small molecules through a mild disruption of the BBB.

Crystallization and preliminary X-ray diffraction of the ZO-binding domain of human occludin

Occludin is a tight-junction protein controlling the integrity of endothelial and epithelial cell layers. It forms complexes with the cytoplasmic proteins ZO-1, ZO-2 and ZO-3. The ZO-binding domain in the C-terminal cytoplasmic region of human occludin has previously been isolated and identified. This domain, as expressed in a bacterial system or isolated from native cellular occludin, maintains its ability to bind ZO-1 and ZO-2. The crystallization conditions of the human ZO-binding domain are reported here. The crystals diffract to 2.3 A resolution and were shown to belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 33.3, b = 35.4, c = 107.3 A.

Study of subclinical cerebral edema in diabetic ketoacidosis by magnetic resonance imaging T2 relaxometry and apparent diffusion coefficient maps

Cerebral edema is the most significant complication in children with diabetic ketoacidosis (DKA). Our goal was to study whether subclinical cerebral edema was preferentially vasogenic or cytotoxic. Magnetic resonance imaging (MRI)--diffusion-weighted imaging (DWI) and T2 relaxometry (T2R)--were obtained in pediatric patients presenting with severe diabetic ketoacidosis (DKA) 6-12 hours after initial DKA treatment and stabilization and 96 hours after correction of DKA. T2 relaxometry was significantly increased during treatment in both white and gray matter, in comparison to the absolute T2R values 96 hours after correction of DKA (p = .034). Classic intracellular cytotoxic edema could not be detected, based on the lack of a statistically significant decrease in ADC values. ADC values were instead elevated, implying a large component of cell membrane water diffusion, correlating with the elevated white and gray matter T2R We discuss the findings in relation to cerebral blood volume, cerebral vasoregulatory dysfunction, and cerebral hyperemia.