Rat Cerebrospinal Fluid Research Articles

Pharmacodynamic effects in the cerebrospinal fluid of rats after intravenous administration of different asparaginase formulations.

Asparaginase (ASNase) is used to treat various hematological malignancies for its capacity to deplete asparagine (ASN) in serum and cerebrospinal fluid (CSF). Since the biological mechanisms underlying CSF asparagine depletion in humans are not yet fully elucidated, this study compared, for the first time, the pharmacological properties of three clinically used ASNase formulations in a rodent model. Male Wistar rats were treated with E.coli-ASNase, PEG-ASNase, or ERW-ASNase at different doses. Serum and CSF amino-acid levels and ASNase activities were evaluated at 1 and 24h after the intravenous administration of different ASNase doses. All the ASNase formulations showed higher activities in serum after 1h than 24h and completely deplete ASN. Mean ASNase activity in the CSF at 1h was higher with ERW-ASNase compared to PEG-ASNase (36±29 vs 8±7U/L, p<0.037) and similar to E.coli-ASNase (21±9U/L, ns). ERW-ASNase and E.coli-ASNase at the highest doses were able to deplete ASN in the CSF after 1h. This effect was transient and not evident at 24h after treatment. Together with the ASN depletion in serum and CSF, a never before demonstrated transient penetration of ASNases into the CSF, more evident for non-pegylated formulations, was detected when the ASNases were administered at high dose.

Association between injury severity and amyloid β protein levels in serum and cerebrospinal fluid in rats with traumatic spinal cord injury.

The aim of the present study was to determine whether amyloid-β (Aβ) protein could be detected in the serum and cerebrospinal fluid (CSF) of rats with traumatic spinal cord injury (SCI) and whether Aβ protein levels in serum and CSF correlated with the injury severity. A total of 140 adult female Sprague‑Dawley rats were randomly divided into four groups: Sham, mild injury, moderate injury and severe injury. Serum and CSF samples were collected at 12h, 1, 3, 7, 14, 21and28days post‑injury. ELISA analysis for serum and CSF Aβ protein was performed. Locomotor function of all animals was assessed using the Basso, Beattie and Bresnahan (BBB) locomotor rating scale. Following SCI, the protein levels of Aβ in serum and CSF samples from SCI groups significantly increased from 12h (P<0.05) and peaked 3days after injury. A significant increase of Aβ levels in serum and CSF in the severe SCI group was also observed at 28days after injury (P<0.05). At 28days after injury the protein levels of Aβ in serum and CSF were significantly correlated with the severity of injury (serum, R2=‑0.806, P<0.01; CSF, R2=‑0.694, P<0.01). A significant correlation between Aβ protein level in serum and CSF and neurological deficits (BBB score) was also observed (P<0.01). The protein level of Aβ in serum and CSF was severity and time‑dependent during the acute phase in rats with traumatic SCI. Monitoring the level of Aβ protein in serum may improve the evaluation of SCI severity and the neuron functional status following SCI.

Anti-Tribbles Pseudokinase 2 (TRIB2)-Immunization Modulates Hypocretin/Orexin Neuronal Functions.

Recent findings showed that 16%-26% of narcolepsy patients were positive for anti-tribbles pseudokinase 2 (TRIB2) antibody, and the intracerebroventricular administration of immunoglobulin-G purified from anti-TRIB2 positive narcolepsy patients caused hypocretin/orexin neuron loss. We investigated the pathophysiological role of TRIB2 antibody using TRIB2-immunized rats and hypocretin/ataxin-3 transgenic (ataxin-3) mice. Plasma, cerebrospinal fluid (CSF), and hypothalamic tissues from TRIB2-immunized rats were collected. Anti-TRIB2 titers, hypocretin contents, mRNA expressions, the cell count of hypocretin neurons, and immunoreactivity of anti-TRIB2 antibodies on hypocretin neurons were investigated. The plasma from ataxin-3 mice was also used to determine the anti-TRIB2 antibody titer changes following the loss of hypocretin neurons. TRIB2 antibody titers increased in the plasma and CSF of TRIB2-immunized rats. The hypothalamic tissue immunostained with the sera from TRIB2-immunized rats revealed positive signals in the cytoplasm of hypcretin neurons. While no changes were found regarding hypothalamic hypocretin contents or cell counts, but there were significant decreases of the hypocretin mRNA level and release into the CSF. The plasma from over 26-week-old ataxin-3 mice, at the advanced stage of hypocretin cell destruction, showed positive reactions against TRIB2 antigen, and positive plasma also reacted with murine hypothalamic hypocretin neurons. Our results suggest that the general activation of the immune system modulates the functions of hypocretin neurons. The absence of a change in hypocretin cell populations suggested that factors other than anti-TRIB2 antibody play a part in the loss of hypocretin neurons in narcolepsy. The increased anti-TRIB2 antibody after the destruction of hypocretin neurons suggest that anti-TRIB2 antibody in narcolepsy patients is the consequence rather than the inciting cause of hypocretin cell destruction.

Penetration and distribution of gadolinium-based contrast agents into the cerebrospinal fluid in healthy rats: a potential pathway of entry into the brain tissue

ObjectiveSignal hyperintensity on unenhanced MRI in certain brain regions has been reported after multiple administrations of some, but not all, gadolinium-based contrast agents (GBCAs). One potential initial pathway of GBCA entry into the brain, infiltration from blood into the cerebrospinal fluid (CSF), was systematically evaluated in this preclinical study.MethodsGBCA infiltration and distribution in the CSF were investigated in healthy rats using repeated fluid-attenuated MRI up to 4 h after high-dose (1.8 mmol/kg) administration of six marketed and one experimental GBCA. Additionally, gadolinium measurements in CSF, blood and brain tissue samples (after 24 h) were performed using inductively coupled plasma mass spectrometry.ResultsEnhanced MRI signals in the CSF spaces with similar distribution kinetics were observed for all GBCAs. No substantial differences in the gadolinium concentrations among the marketed GBCAs were found in the CSF, blood or brain tissue. After 4.5 h, the concentration in the CSF was clearly higher than in blood but was almost completely cleared and lower than the brain tissue concentration after 24 h.ConclusionsIn contrast to the brain signal hyperintensities, no differences in penetration and distribution into the CSF of healthy rats exist among the marketed GBCAs.Key Points• Gadolinium-based contrast agents can cross the blood-CSF barrier.• Fluid-attenuated MRI shows GBCA distribution with CSF flow.• GBCA structure and physicochemical properties do not impact CSF penetration and distribution.• GBCA clearance from CSF was almost complete within 24 h in rats.• CSF is a potential pathway of GBCA entry into the brain.

Characterization of FRM-36143 as a new γ-secretase modulator for the potential treatment of familial Alzheimer's disease.

BackgroundFamilial Alzheimer’s disease (FAD) is caused by mutations in the amyloid precursor protein (APP) or presenilin (PS). Most PS mutations, which account for the majority of FAD cases, lead to an increased ratio of longer to shorter forms of the amyloid beta (Aβ) peptide. The therapeutic rationale of γ-secretase modulators (GSMs) for Alzheimer’s disease is based on this genetic evidence as well as on enzyme kinetics measurements showing changes in the processivity of the γ-secretase complex. This analysis suggests that GSMs could potentially offset some of the effects of PS mutations on APP processing, thereby addressing the root cause of early onset FAD. Unfortunately, the field has generated few, if any, molecules with good central nervous system (CNS) drug-like properties to enable proof-of-mechanism studies.MethodWe characterized the novel GSM FRM-36143 using multiple cellular assays to determine its in vitro potency and off-target activity as well as its potential to reverse the effect of PS mutations. We also tested its efficacy in vivo in wild-type mice and rats.ResultsFRM-36143 has much improved CNS drug-like properties compared to published GSMs. It has an in vitro EC50 for Aβ42 of 35 nM in H4 cells, can reduce Aβ42 to 58 % of the baseline in rat cerebrospinal fluid, and also increases the non-amyloidogenic peptides Aβ37 and Aβ38. It does not inhibit Notch processing, nor does it inhibit 24-dehydrocholesterol reductase (DHCR24) activity. Most interestingly, it can reverse the effects of presenilin mutations on APP processing in vitro.ConclusionsFRM-36143 possesses all the characteristics of a GSM in terms of Aβ modulation Because FRM-36143 was able to reverse the effect of PS mutations, we suggest that targeting patients with this genetic defect would be the best approach at testing the efficacy of a GSM in the clinic. While the amyloid hypothesis is still being tested with β-site APP-cleaving enzyme inhibitors and monoclonal antibodies in sporadic AD, we believe it is not a hypothesis for FAD. Since GSMs can correct the molecular defect caused by PS mutations, they have the promise to provide benefits to the patients when treated early enough in the course of the disease.

IMPROVING COGNITIVE FUNCTION IN RODENTS VIA INCREASING GLYCINE LEVELS IN BRAIN BY THE NOVEL GLYCINE TRANSPORTER-1 INHIBITOR BI 425809

Dysfunction of the glutamatergic system related to the NMDA receptor may play an important role in cognitive impairment in Alzheimer’s disease. One approach to counteract this is the extracellular increase of the NMDA receptor co-agonist glycine by glycine transporter-1 (GlyT1) inhibition. Thus, inhibiting GlyT1 has potential for treating memory impairment in Alzheimer’s disease via strengthening glutamatergic neurotransmission. Previous studies with GlyT1-inhibitors show memory-enhancing effects in animals. This study characterizes the potency and selectivity of the novel GlyT1 inhibitor BI 425809 and its effects on glycine increase in rat cerebrospinal fluid (CSF). BI 425809 was also evaluated in two rodent cognition tasks assessing episodic memory and working memory. The molecular potency of BI 425809 for GlyT1 was determined by inhibition of [3H]-glycine uptake in human SK-N-MC cells and rat primary cortical neurons. Selectivity was tested against GlyT2 and other off-targets by uptake and receptor binding assays, respectively. Concentrations of glycine in rat CSF samples collected from cisterna magna following oral administration of BI 425809 were determined by HPLC-MS/MS technique. BI 425809 was tested after oral application in the mouse T-maze spontaneous alternation test and in the social recognition test in naive rats. The IC50 value of BI 425809 on GlyT1 was 4.0 nM in SK-N-MC cells and 4.4 nM in rat primary neurons. BI 425809 demonstrated no relevant activity against GlyT2 (IC50 >10 μM) and 103 off-targets at 10 μM. A dose-dependent increase of glycine in rat CSF was observed. BI 425809 reversed MK-801-induced memory deficits in the mouse T-maze (working memory) and improved memory performance in the rat social recognition task (episodic memory). BI 425809 is a potent and selective GlyT1 inhibitor. Systemic administration of BI 425809 led to an increase in glycine levels in rat CSF demonstrating functional target engagement – i.e. GlyT1 inhibition in the brain – showing that glycine levels in CSF can be used to assess GlyT1 inhibition centrally. This might also be used to evaluate central target engagement in clinical trials. BI 425809 showed memory enhancing effects in animal cognition tests. GlyT1 inhibition may be a potential approach to pharmacologically improve cognition in Alzheimer’s disease.

Plasminogen Activator Inhibitor-1 in depression: Results from Animal and Clinical Studies.

Evidence suggests that plasminogen activator inhibitor-1 (PAI-1) is a stress-related factor, and serum PAI-1 levels are increased in patients with major depressive disorders (MDD). Herein, we analysed PAI-1 protein levels in the brain, cerebrospinal fluid (CSF) and serum of rodents exposed to chronic unpredictable mild stress or treated with escitalopram. In addition, we examined PAI-1 concentrations in serum obtained from 17 drug-free depressed patients before and after escitalopram treatment. We found that PAI-1 expression was increased in area 1 of the cingulate cortex and prelimbic cortex of the medial prefrontal cortex as well as in the hippocampal cornu ammonis 3 and dentate gyrus in stressed rats. A downregulation of PAI-1 following chronic escitalopram treatment was also found. PAI-1 levels were higher in the CSF and serum in stressed rats than in controls, although the difference did not reach statistical significance in the serum. Escitalopram treatment significantly decreased PAI-1 levels in the serum, but not in the CSF. MDD patients had significantly greater serum PAI-1 concentrations than controls. Our results suggest that PAI-1 is implicated in the pathophysiology of depression.

Erratum to: Progressive changes of orexin system in a rat model of 6-hydroxydopamine-induced Parkinson’s disease

[This corrects the article DOI: 10.1007/s12264-010-0410-9.].

Neuromyelitis optica study model based on chronic infusion of autoantibodies in rat cerebrospinal fluid.

BackgroundDevic’s neuromyelitis optica (NMO) is an autoimmune astrocytopathy, associated with central nervous system inflammation, demyelination, and neuronal injury. Several studies confirmed that autoantibodies directed against aquaporin-4 (AQP4-IgG) are relevant in the pathogenesis of NMO, mainly through complement-dependent toxicity leading to astrocyte death. However, the effect of the autoantibody per se and the exact role of intrathecal AQP4-IgG are still controversial.MethodsTo explore the intrinsic effect of intrathecal AQP4-IgG, independent from additional inflammatory effector mechanisms, and to evaluate its clinical impact, we developed a new animal model, based on a prolonged infusion of purified immunoglobulins from NMO patient (IgGAQP4+, NMO-rat) and healthy individual as control (Control-rat) in the cerebrospinal fluid (CSF) of live rats.ResultsWe showed that CSF infusion of purified immunoglobulins led to diffusion in the brain, spinal cord, and optic nerves, the targeted structures in NMO. This was associated with astrocyte alteration in NMO-rats characterized by loss of aquaporin-4 expression in the spinal cord and the optic nerves compared to the Control-rats (p = 0.001 and p = 0.02, respectively).In addition, glutamate uptake tested on vigil rats was dramatically reduced in NMO-rats (p = 0.001) suggesting that astrocytopathy occurred in response to AQP4-IgG diffusion. In parallel, myelin was altered, as shown by the decrease of myelin basic protein staining by up to 46 and 22 % in the gray and white matter of the NMO-rats spinal cord, respectively (p = 0.03). Loss of neurofilament positive axons in NMO-rats (p = 0.003) revealed alteration of axonal integrity. Then, we investigated the clinical consequences of such alterations on the motor behavior of the NMO-rats. In a rotarod test, NMO-rats performance was lower compared to the controls (p = 0.0182). AQP4 expression, and myelin and axonal integrity were preserved in AQP4-IgG-depleted condition. We did not find a major immune cell infiltration and microglial activation nor complement deposition in the central nervous system, in our model.ConclusionsWe establish a link between motor-deficit, NMO-like lesions and astrocytopathy mediated by intrathecal AQP4-IgG. Our study validates the concept of the intrinsic effect of autoantibody against surface antigens and offers a model for testing antibody and astrocyte-targeted therapies in NMO.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-016-0577-8) contains supplementary material, which is available to authorized users.

598. TARGTCNS for the Treatment of Central Nervous System Disorders

Diseases and disorders of the central nervous system (CNS) represent a large field of unmet need that significantly impacts the lifespan and quality of life of many patients. The ability to deliver therapeutic proteins from the systemic circulation to the CNS is hampered by the blood-brain barrier (BBB). A number of strategies have been developed to allow therapies to cross the BBB, but to date with limited success. We have developed a novel localized approach to deliver protein and peptide therapeutics to the CNS based on our proprietary Transduced Autologous Restorative Gene Therapy system (TARGT™) platform. TARGT is based on autologous dermal micro-organs (MO) harvested and transduced ex-vivo to produce a therapeutic protein and then re-implanted in the patient. In this study we assessed whether TARGT can survive and deliver sustained localized protein post implantation into the CNS. In rats, MOs, 2×1mm each, were harvested from Lewis rat skin, characterized in-vitro, and then implanted in the Lewis rats’ cisterna magna. The procedure was well-tolerated and without observed behavioral change in all implanted rats. Histopathology of MOs excised several weeks post implantation, demonstrated viable and integrated MOs without signs of implant rejection. In the second phase, rat MOs were processed ex-vivo into TARGT secreting erythropoietin (TARGTEPO) by transduction with Helper Dependent Adenoviral vector encoding human erythropoietin (HDAd-HuEPO). Rat TARGTs secreting human EPO were then implanted into Lewis rats’ cisterna magna. Post implantation, cerebrospinal fluid (CSF) and serum were collected and EPO levels were measured by HuEPO ELISA. Results obtained suggest that implantation was well tolerated with no observed signs of rejection. Measurable human EPO levels were detected in rat CSF for the duration of the experiment. Detectable but low levels of Hu-EPO were also measured in the rat serum, as expected, since CSF drains into the peripheral blood. In pigs we have tested the viability and monoclonal antibody secretion from TARGTs into the CNS. Humira, an established antibody drug, was selected as a proof of concept. Pig MOs were harvested and transduced with the HDAd vector carrying the Humira sequence. Two TARGTHumira were implanted in the pig subdural space at the parietal convexity region and the pig was followed for one week post implantation. Results obtained post implantation suggests no observed pig's behavioral change. Humira was measured in CSF samples taken from the implantation area and the lumbar space. One week post implantation, TARGTs were excised out of the pig brain when they are viable and no signs of inflammation or damage to the brain tissue were observed. These results demonstrate that TARGT is a promising novel therapeutic platform with the potential for treatment of CNS disorders. We are now actively studying TARGTCNS treatment of lysosomal storage diseases and brain malignancies.

On-line preconcentration of fluorescent derivatives of catecholamines in cerebrospinal fluid using flow-gated capillary electrophoresis

Flow-gated capillary electrophoresis (CE) coupled with microdialysis has become an important tool for in vivo bioanalytical measurements because it is capable of performing rapid and efficient separations of complex biological mixtures thus enabling high temporal resolution in chemical monitoring. However, the limit of detection (LOD) is often limited to a micro- or nano-molar range while many important target analytes have picomolar or sub-nanomolar levels in brain and other tissues. To enhance the capability of flow-gated CE for catecholamine detection, a novel and simple on-line sample preconcentration method was developed exclusively for fluorescent derivatives of catecholamines that were fluorogenically derivatized with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide. The effective preconcentration coupled with the sensitive laser-induced fluorescence (LIF) detection lowered the LOD down to 20pM for norepinephrine (NE) and 50pM for dopamine (DA) at 3-fold of S/N ratio, and the signal enhancement was estimated to be over 100-fold relative to normal injection when standard analytes were dissolved in artificial cerebrospinal fluid (aCSF). The basic focusing principle is novel since the sample plug contains borate while the background electrolyte (BGE) is void of borate. This strategy took advantage of the complexation between diols and borate, through which one negative charge was added to the complex entity. The sample derivatization mixture was electrokinetically injected into a capillary via the flow-gated injection, and then NE and DA derivatives were selectively focused to a narrow zone by the reversible complexation. Separation of NE and DA derivatives was executed by incoming surfactants of cholate and deoxycholate mixed in the front BGE plug. This on-line preconcentration method was finally applied to the detection of DA in rat cerebrospinal fluid (CSF) via microdialysis and on-line derivatization. It is anticipated that the method would be valuable for in vivo monitoring of DA and NE in various brain regions of live animals on flow-gated CE or microchip platforms.

5-HT(1A) receptor antagonist improves behavior performance of delirium rats through inhibiting PI3K/Akt/mTOR activation-induced NLRP3 activity.

Postoperative delirium is a common complication that often results in poor outcomes in surgical and elderly patients. Accumulating evidences suggest that the pathophysiology of delirium results from multiple neurotransmitter system dysfunctions. To further clarify the effects of the selective serotonin (5-HT) (1A) antagonist WAY-100635 on the behaviors in scopolamine induced-delirium rats and to explore the molecular mechanism, in this study, we investigated the change of monoamine levels in the cerebrospinal fluid (CSF) and different brain regions using high-performance liquid chromatography and assessed the behavioral retrieval of delirium rats treated with WAY-100635. It was found that 5-hydroxy-3-indoleacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid, and homovanillic acid concentrations in the CSF of scopolamine-induced delirium rats were significantly increased, among which 5-HIAA was also increased in hippocampus and basolateral amygdala (BLA), and 5-HT(1A) receptor was significantly higher in the hippocampuses and BLA than other brain regions. Furthermore, intrahippocampus and intra-BLA stereotactic injection of WAY-100635 improved the delirium-like behavior of rats. Mechanistically, after WAY-100635 treatment, significant reduction of IL-1β release into CSF and NOD-like receptor family, pyrin domain containing 3 (NLRP3) expression, phosphorylated phosphatidylinositol-3-kinase (PI3K), protein kinase B (AKT), and S6K was observed. Altogether, these results suggest that delirium rats induced by scopolamine may be correlated with an increased cerebral concentration of 5-HT and dopamine neurotransmitters system; the selective 5-HT(1A) antagoniszts can reverse the delirium symptoms at some extent through tendering PI3K/Akt/mammalian target of rapamycin complex 1 (mTOR) activation-induced NLRP3 activity and then reducing IL-1β release.

Ventricular-subcutaneous shunt for the treatment of experimental hydrocephalus in young rats: technical note.

Hydrocephalus is a complex disease that affects cerebrospinal fluid (CSF) dynamics and is very common in children. To this date, CSF shunting is still the standard treatment for childhood hydrocephalus, but, nevertheless, the effects of such an operation on the developing brain are widely unknown. To help overcome this, experimental models of CSF shunts are surely very useful tools. The objective of this study was to describe a feasible and reliable technique of an adapted ventricular-subcutaneous shunt for the treatment of kaolin-induced hydrocephalus in young rats. We developed a ventricular-subcutaneous shunt (VSCS) technique which was used in 31 Wistar young rats with kaolin-induced hydrocephalus. Hydrocephalus was induced at 7days of age, and shunt implantation was performed 7days later. Our technique used a 0.7-mm gauge polypropylene catheter tunneled to a subcutaneous pocket created over the animal's back and inserted into the right lateral ventricle. All animals were sacrificed 14days after shunt insertion. Twenty-four rats survived and remained well until the study was ended. No major complications were seen. Their weight gain went back to normal. They all underwent ambulatory behavioral testing prior and after VSCS, which showed improvement in their motor skills. We have also obtained magnetic resonance (MR) scans of 16 pups confirming reduction of ventricular size after shunting and indicating effective treatment. Histopathological analysis of brain samples before and after shunting showed reversion of ependymal and corpus callosum disruption, as well as fewer reactive astrocytes in shunted animals. An experimental CSF shunt technique was devised. Excessive CSF of hydrocephalic rats is diverted into the subcutaneous space where it can be resorbed. This technique has a low complication rate and is effective. It might be applied to various types of experimental studies involving induction and treatment of hydrocephalus.

An applicable method of drawing cerebrospinal fluid in rats

BackgroundComponent analysis of cerebrospinal fluid (CSF) is frequently required to probe the causes and pathologic mechanisms of disease and effective drugs in experimental studies of the central nervous system. Rat and mouse are two kinds of most frequently used animals in experimental studies. Rats are considered to be the most suitable animal for experimental analysis of CSF both on cost and manipulability as mice are too small for drawing CSF. However, drawing CSF from rats is still not easy, which makes many researchers choose bigger animals, such as rabbits. This paper introduced a highly applicable technique of CSF collection from cerebellomedullary cistern (CC) in rats. MethodsCSF collection with this technique was performed by direct CC puncture using a collection apparatus with negative pressure. The apparatus consists of a 1ml syringe, a disposable intravenous infusion needle and a clip. The needle was cut and made less sharp than the original one to avoid injury to the brain and spinal cord. ResultsWe have collected CSF multiple times from each rat with this approach and the collection lasted less than 30s each time on average. The length of the collection needles of the CSF was conformed to the different body sizes (weight) of the rats in the 3 groups. Compared with currently existing methods, this is faster, safer, simpler and repeatable. ConclusionsCSF collection by CC puncture using a negative pressure collection apparatus is fast to operate, safe to the rats, and maximum amount of CSF can be collected.

Formulation of gentamicin as surface modified self-nanoemulsifying formulations (SNEFs) improves its anti-pneumococcal activity

Abstract Surface modified self-nanoemulsifying formulations (SNEFs) loaded with gentamicin were formulated using suitable blends of soybean oil, a mixture of Kolliphor® P188 and Kolliphor® EL as surfactants, and Transcutol® HP as co-surfactant, and administered orally to white albino rats for evaluation of anti-pneumococcal activity against Streptococcus pneumoniae. Droplet size and zeta potential measurements showed that SNEFs had mean droplet sizes in the range of 80.7±0.5–210.2±0.0, and were stable with mean zeta potential in the range of –25.2±3.0 to –42.5±1.3 mV. Preliminary screening against S. pneumoniae in vitro revealed that gentamicin-loaded SNEFs had better bacterial inhibition than the standard drug, and at a low minimum inhibitory concentration (MIC) of 2.5 mg/mL. Gentamicin delivered into cerebrospinal fluid of rats from orally administered SNEFs produced a prolonged and enhanced activity against S. pneumoniae at a dose of 7 mg/kg than the standard drug at the same dose. Hence, results from this study showed that the activity of gentamicin against S. pneumoniae was improved by formulation as surface modified SNEFs.

Rapid discovery and identification of multiple absorbed chemical constituents and metabolites in rat cerebrospinal fluid after oral administration of Jitai tablets by a LC-MS based metabolomics approach

An integrative strategy using LC-Q/TOF-MS and LC-QqQ-MS/MS coupled with multi-variate statistical analysis was developed to screen and identify the constituents transported into the rat cerebrospinal fluid after oral administration of Jitai tablets.

Nimodipine-Loaded Pluronic® Block Copolymer Micelles: Preparation, Characterization, In-vitro and In-vivo Studies.

Nimodipine (NM), as a lipophilic calcium channel blocker indicated for the prevention and treatment of neurological disorders, suffers from an extensive first pass metabolism, resulting in low oral bioavailability. Polymeric micelles, self-assembled from amphiphilic polymers, have a core-shell structure which makes them unique nano-carriers with excellent performance as drug delivery. This investigation was aimed to develop NM-loaded polymeric micelles and evaluate their potential to cross the blood brain barrier (BBB). Micelles from Pluronics®P85, F127 and F68 were fabricated for the delivery of NM, using thin film hydration and direct dissolution techniques. Critical micelle concentration of the drug-free micelles was determined by pyrene fluorescence spectroscopy. Dynamic light scattering showed that in most cases, micelles less than 100 nm and low polydispersity indices were successfully developed. Transmission electron microscopy demonstrated spherical shape of micelles. The NM-loaded micelles were also characterized for particle size, morphology, entrapment efficiency, drug loading , in vitro drug release in phosphate buffer and artificial cerebrospinal fluid (CSF). Stability was assessed from size analysis, clarity of dispersion on standing and EE(%), following 3 months storage at room temperature. The in-vitro release of NM from polymeric micelles presented the sustained-release profile. Animal studies revealed the existence of fluorescein 5-isothiocyanate-labeled micelles in rat CSF following intraperitoneal administration, proving that the micelles crossed the BBB. Anticonvulsant effect of NM was shown to be significantly greater than that of NM solution. Our results confirmed that Pluronic micelles might serve as a potential nanocarrier to improve the activity of NM in brain.

Complement receptor 2 is up regulated in the spinal cord following nerve root injury and modulates the spinal cord response.

BackgroundActivation of the complement system has been implicated in both acute and chronic states of neurodegeneration. However, a detailed understanding of this complex network of interacting components is still lacking.MethodsLarge-scale global expression profiling in a rat F2(DAxPVG) intercross identified a strong cis-regulatory influence on the local expression of complement receptor 2 (Cr2) in the spinal cord after ventral root avulsion (VRA). Expression of Cr2 in the spinal cord was studied in a separate cohort of DA and PVG rats at different time-points after VRA, and also following sciatic nerve transection (SNT) in the same strains. Consequently, Cr2−/− mice and Wt controls were used to further explore the role of Cr2 in the spinal cord following SNT. The in vivo experiments were complemented by astrocyte and microglia cell cultures.ResultsExpression of Cr2 in naïve spinal cord was low but strongly up regulated at 5–7 days after both VRA and SNT. Levels of Cr2 expression, as well as astrocyte activation, was higher in PVG rats than DA rats following both VRA and SNT. Subsequent in vitro studies proposed astrocytes as the main source of Cr2 expression. A functional role for Cr2 is suggested by the finding that transgenic mice lacking Cr2 displayed increased loss of synaptic nerve terminals following nerve injury. We also detected increased levels of soluble CR2 (sCR2) in the cerebrospinal fluid of rats following VRA.ConclusionsThese results demonstrate that local expression of Cr2 in the central nervous system is part of the axotomy reaction and is suggested to modulate subsequent complement mediated effects.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-015-0413-6) contains supplementary material, which is available to authorized users.

Nasal chitosan microparticles target a zidovudine prodrug to brain HIV sanctuaries

Zidovudine (AZT) is an antiretroviral drug that is a substrate of active efflux transporters (AETs) that extrude the drug from the central nervous system (CNS) and macrophages, which are considered to be sanctuaries of HIV. The conjugation of AZT to ursodeoxycholic acid is known to produce a prodrug (UDCA–AZT) that is able to elude the AET systems, indicating the potential ability of this prodrug to act as a carrier of AZT in the CNS and in macrophages. Here, we demonstrate that UDCA–AZT is able to permeate and remain in murine macrophages with an efficiency twenty times higher than that of AZT. Moreover, we propose the nasal administration of this prodrug in order to induce its uptake into the CNS. Chitosan chloride-based microparticles (CP) were prepared by spray-drying and were characterized with respect to size, morphology, density, water uptake and the dissolution profile of UDCA–AZT. The CP sample was then nasally administered to rats. All in vitro and in vivo measurements were also performed for a CP parent physical mixture. The CP sample was able to increase the dissolution rate of UDCA–AZT and to reduce water uptake with respect to its parent physical mixture, inducing better uptake of UDCA–AZT into the cerebrospinal fluid of rats, where the prodrug can act as an AZT carrier in macrophages.

Elevated Tau Level in Aged Rat Cerebrospinal Fluid Reduced by Treatment with a Neurotrophic Compound.

Alzheimer's disease (AD) is the single major cause of dementia in middle- to old-age individuals, and, as of yet, no disease-modifying therapeutic drug is available for its treatment. A major obstacle in the successful development of disease-modifying therapeutic drugs has been the lack of suitable animal models of the sporadic form of AD as well as a biomarker that can be used both for therapeutic preclinical studies and for human clinical trials. Previously we showed neurogenesis and neuronal plasticity deficits and cognitive impairment and their rescue with a neurotrophic peptidergic compound, DGGLAG named P021, in aged Fisher rats. Here we show that P021 is blood-brain-barrier-permeable, and chronic oral treatment with this compound can reduce the brain level of total tau in the aged rats. Furthermore, cerebrospinal fluid (CSF) levels of both tau and Aβ/AβPP are elevated in the aged animals, and chronic treatment with P021 can reduce tau but not Aβ/AβPP to that of the levels found in young adult rats. Importantly, P021 does not induce any detectable immune reaction in rats. Collectively, these studies show the therapeutic potential of P021 as a disease-modifying compound and the suitability of the aged Fisher rats as a model of cerebral aging in which the therapeutic efficacy of a tau-reducing compound can be monitored in the CSF.