Postinjection Hours Research Articles

Perspective: Risks/adverse events for epidural spinal injections.

Despite the lack of FDA (Food and Drug Administration) approval, cervical and lumbar epidural spinal injections are frequently performed in the US to address back pain and/or painful radiculopathy. The three major types of injections include; interlaminar/translaminar (ESI), transforaminal (TFESI), or caudal injections. Notably, most studies document little to no clear short-term, and no long-term benefits/efficacy for these injections vs. various placebos. More adverse events (AE) occurred with cervical© rather than lumbar (L) injections, and more severe AE were attributed to C-TFESI vs. CESI injections. Acute post injection AE symptoms were observed immediately or within 72 post-injection hours. These symptoms included; hypotension, acute respiratory distress, chest pain, upper extremity numbness, weakness, paresthesias, paralysis, and fevers. More AE were attributed to cervical C-TFESI vs. cervical CESI. These AE included; intramedullary/cord injections, intravascular injections (i.e. vertebral artery) resulting in brain stem/cerebellar/cord strokes, epidural abscess/infection, confusion, epidural hematomas, intracranial hypotension, and/or 6th nerve cranial palsies. AE for lumbar LESI/L-TFESI included; infections/abscess, epidural hematomas/subdural hematomas, intravascular injections, cerebrospinal fluid (CSF) leaks/dural tears (DT), and intracranial/postural hypotension. Notably, the vast majority of studies showed little to no short-term, and no long-term benefits for cervical or lumbar ESI/TFESI vs placebos (i.e. mostly consisting of normal saline alone, or saline plus local anesthesia). Epidural cervical and lumbar ESI or TFESI spinal injections demonstrated minimal to no short-term, and no long-term benefits for the treatment of cervical and/or lumbar pain/radiculopathy vs. placebos. Further, more AE were observed for cervical vs. lumbar epidural injections overall, with more AE usually seen with TFESI vs. ESI procedures.

Activation of orexin-A (hypocretin-1) receptors in the Raphe Pallidus at different ambient temperatures in the rat: effects on thermoregulation, cardiovascular control, sleep, and feeding behavior.

The Raphe Pallidus (RPa) is a brainstem nucleus containing sympathetic premotor neurons that control thermogenesis and modulate cardiovascular function. It receives inputs from various hypothalamic areas, including the Lateral Hypothalamus (LH), a heterogeneous region intricately involved in several autonomic and behavioral functions. A key subpopulation of neurons in the LH expresses orexin/hypocretin, a neuropeptide which is crucially involved in the regulation of the wake-sleep states and feeding behavior. The RPa receives orexinergic projections from the LH and orexinergic signalling in the RPa has been shown to enhance thermogenesis in the anaesthetized rat, but only in the presence of an already existing thermogenic drive, without significantly affecting cardiovascular function. The present work was aimed at exploring the effects on thermoregulation and autonomic function and the possible role in the modulation of the wake-sleep states and feeding behavior of orexin injection in the RPa in the free-behaving rat. In order to assess the influence of an already present thermogenic drive on orexinergic signalling in the RPa, animals were studied at three different ambient temperatures (Ta, 10°C, 24°C, and 32°C). We found that orexin injection into the RPa variably affected the wake-sleep states, autonomic functions, motor activity, and feeding behavior, at the different Tas. In particular, in the first post-injection hour, we observed an increase in wakefulness, which was large at Ta 24°C and Ta 10°C and rather mild at Ta 32°C. Deep brain temperature was increased by orexin injection at Ta 10°C, but not at either Ta 24°C or Ta 32°C. Moreover, an increase in mean arterial blood pressure occurred at Ta 24°C, which was probably masked by the high baseline levels at Ta 10°C and was completely absent at Ta 32°C. Finally, an enhancement in feeding behavior was observed at Ta 24°C and 10°C only. In accordance with what observed in anaesthetized rats, orexinergic signalling in the RPa seems to be ineffective in the absence of any thermogenic drive. Moreover, the effects observed on the wake-sleep states and feeding behavior introduce the RPa as a novel player in the central neural network promoting wakefulness and feeding.

Effects and mechanism of annexin A1-overexpressing human adipose-derived mesenchymal stem cells in the treatment of mice with acute respiratory distress syndrome

Effects and mechanism of annexin A1-overexpressing human adipose-derived mesenchymal stem cells in the treatment of mice with acute respiratory distress syndrome

Safety and Synovial Inflammatory Response After Intra-articular Injection of Botulinum Toxin Type A in Healthy Horses

Botulinum toxin type A (BoNT-A) is a promising alternative for patients suffering from chronic joint pain. The aim of this study was to investigate whether a single injection of BoNT-A would produce adverse effects on clinical parameters and synovial parameters as well as lameness. One randomly selected radiocarpal joint was treated with 50 U of BoNT-A in eight horses, and the contralateral joint received saline solution. All horses received injections at day 0 and were re-evaluated twice daily for 7 days for heart rate (HR), respiratory rate (RR), rectal temperature (RT), mucous membrane color, capillary refill time, intestinal motility, appetite, water intake, defecation, urination, and attitude. At these same time points, joint pain and circumference were assessed. Objective lameness evaluations were performed once daily for 7 days and synovial fluid samples were collected at baseline, post-injection hour (PIH) 24 and PIH 168 and evaluated for synovial fluid parameters. HR and RT remained clinically unaltered, despite oscillations over time (P = .001). The remaining clinical parameters were unaltered by treatment or time (P > .05). Joint pain was not elicited by flexion and palpation in both limbs as well as carpal circumference was not altered (P = .88). Lameness was observed only on saline limbs. Cellular parameters evaluated in synovial fluid samples from both carpi had significantly increased from baseline to PIH 24, decreasing at PIH 168 (P < .05). It was concluded that the injection of 50 U BoNT-A is suggested to be a safe therapy for intra-articular use in horses and must be verified by further investigation.

The lipopolysaccharide model for the experimental induction of transient lameness and synovitis in Standardbred horses

An established lipopolysaccharide (LPS) model previously described in Warmbloods, was inconsistent in Standardbred horses, where lameness was not detected despite the presence of synovitis. The present study aimed to determine the dose of LPS from E. coli O55:B5 required to induce mild to moderate lameness following middle carpal joint injection in Standardbred horses and to quantitate the induced lameness over time, with and without anti-inflammatory pre-treatment. In a baseline trial, eight healthy, clinically sound Standardbred horses were used in a rule-based dose-escalation design trial, starting at a dose of 10 endotoxin units (EU). Lameness at trot was evaluated visually and quantitatively (using an inertial-sensor system and pressure plate analysis). Synovial fluid aspirates were analysed for total nucleated cell counts, total protein and prostaglandin E2 (PGE2). Following 2 months wash-out, the effective LPS-dose determined in the baseline trial was used to evaluate the effect of anti-inflammatory treatment. A mixed model for repeated measures with horse as random effect was used for analysis.After injection of 10 EU LPS, the desired degree of lameness was observed in the baseline trial, with maximal lameness at post-injection hour (PIH) 4, followed by a rapid decline and return to baseline by PIH 48. No lameness was observed following pre-treatment with meloxicam. In synovial fluid, PGE2 was significantly higher at PIH 8 and PIH 24 in the baseline trial compared with following meloxicam pre-treatment. In conclusion, injection of the middle carpal joint with 10 EU LPS consistently induces a transient lameness and synovitis in Standardbred horses.

Sleep inhibition induced by amyloid‐β oligomers is mediated by the cellular prion protein

Sleep is severely impaired in patients with Alzheimer's disease. Amyloid-β deposition in the brain of Alzheimer's disease patients is a key event in its pathogenesis and is associated with disrupted sleep, even before the appearance of cognitive decline. Because soluble amyloid-β oligomers are the key mediators of synaptic and cognitive dysfunction in Alzheimer's disease and impair long-term memory in rodents, the first aim of this study was to test the hypothesis that amyloid-β oligomers would directly impair sleep in mice. The cellular prion protein is a cell surface glycoprotein of uncertain function. Because cellular prion protein binds oligomeric amyloid-β with high affinity and mediates some of its neurotoxic effects, the second aim of the study was to test whether amyloid-β oligomer-induced sleep alterations were mediated by cellular prion protein. To address these aims, wild-type and cellular prion protein-deficient mice were given acute intracerebroventricular injections (on different days, at lights on) of vehicle and synthetic amyloid-β oligomers. Compared to vehicle, amyloid-β oligomers significantly reduced the amount of time spent in non-rapid eye movement sleep by wild-type mice during both the light and dark phases of the light-dark cycle. The amount of time spent in rapid eye movement sleep was reduced during the dark phase. Sleep was also fragmented by amyloid-β oligomers, as the number of transitions between states increased in post-injection hours 9-24. No such effects were observed in cellular prion protein-deficient mice. These results show that amyloid-β oligomers do inhibit and fragment sleep, and that these effects are mediated by cellular prion protein.

Febrile and sleep responses to an immune challenge are affected by trait aggressiveness in rats

Sleep is altered in response to an immune challenge: non-rapid eye movement (NREM) sleep is increased and fragmented, REM sleep is inhibited. Sleep and immune response are affected by stress: several stressors inhibit sleep and increase waking time; stress-induced cortisol secretion affects the immune response, with immunosuppressive effects. Different levels of trait aggressiveness are associated with specific patterns of neuroendocrine and autonomic stress responsiveness.Aim of this study was to test the hypothesis that trait aggressiveness, by affecting response to stressors, modifies sleep alterations induced by the activation of the immune response. To this aim, rats were selected on the basis of their latency time to attack a male intruder in the resident-intruder test. Animals were instrumented for chronic recordings of sleep-wake activity and injected, intraperitoneally, with an immune challenge (250 μg/kg lipopolysaccharide – LPS, a component of gram-negative bacterial cell wall).Here we report that high aggressive (HA) rats responded to an immune challenge with a 24-h long increase in cortical brain temperature. During the first 12 post-injection hours, HA rats also responded with a prolonged increase in NREM sleep amount, and a 5-h long and continuous inhibition of REM sleep. In HA rats, the LPS-induced increase in the amount of time spent in NREM sleep was due to an increase in the number of episodes of this sleep phase, without any change in the bout duration. The LPS-induced REM sleep inhibition observed in HA rats was due to a decrease in both the number and duration of REM sleep bouts. In HA rats, during REM sleep, LPS administration significantly reduced the power of the EEG theta band. In non-aggressive (NA) rats, in response to LPS administration, cortical brain temperature was increased only for two hours, NREM sleep was unaffected, and REM sleep inhibition was scattered along the first 8 post-injection hours. The LPS-induced changes in the number of NREM sleep bouts of NA rats were limited to few and scattered hours, with a change in bout duration only in a single hour. A combination of decreases, in few hours, in both REM sleep bouts and their duration contributed to the REM sleep inhibition observed in NA rats. In NA rats, the power of EEG theta band was not modified, during REM sleep, by LPS administration. Gross motor activity was inhibited in both HA and NA rats.Results of this study show that trait aggressiveness affects febrile and sleep responses to an immune challenge.

Induction of Synovitis Using Interleukin-1 Beta: Are There Differences in the Response of Middle Carpal Joint Compared to the Tibiotarsal Joint?

Background: The effects of recombinant interleukin-1β (rIL-1β) have been described for the middle carpal joint (MCJ). However, we are unaware of any studies that have described the cytological response of the tibiotarsal joint (TTJ) to rIL-1β or compared the clinical and cytological responses of the MCJ to the TTJ following the administration of intra-articular rIL-1β. Such information is critical for researchers planning to use rIL-1β to create acute synovitis models in horses.Objectives: To compare the clinical and cytological responses of the MCJ to the TTJ following administration of intra-articular rIL-1β.Methods: Twelve horses were used for the study. Eight horses received 75 ng of rIL-1β into the MCJ and four horses received 75 ng of rIL-1β into the TTJ. Clinical and cytological outcome parameters including lameness, joint circumference, joint effusion score, total nucleated cell count, cellular differentials, C-reactive protein, and prostaglandin-E2 concentrations were determined at baseline and multiple post-treatment time points over a 336 h period (2 weeks).Results: Recombinant IL-1β administered into the TTJ resulted in a significantly greater respiratory rate at 24 h and heart rate at 12 h when compared to rIL-1β administered into the MCJ. In addition, the TTJ had a significantly greater increase in joint circumference at 24 post-injection hour (PIH) and subjective effusion grade at 24 PIH and 336 PIH. The MCJ had significantly higher total protein concentration at 6 PIH, and a significantly higher NCC at 24 and 72 PIH when compared to the TTJ. Conversely, the TTJ had significantly higher neutrophilic infiltration than the MCJ at 6 PIH and 168 PIH.Conclusions: This study establishes that the same intra-articular dose of rIL-1 β elicits significantly different clinical and cytological responses in the MCJ compared to the TTJ in the equine model of intra-articular synovitis. In addition, clinical and cytological evidence of synovitis may persist up to or >1 week following intra-articular administration of rIL-1 β.

Changes in concentrations of haemostatic and inflammatory biomarkers in synovial fluid after intra-articular injection of lipopolysaccharide in horses

BackgroundSeptic arthritis is a common and potentially devastating disease characterized by severe intra-articular (IA) inflammation and fibrin deposition. Research into equine joint pathologies has focused on inflammation, but recent research in humans suggests that both haemostatic and inflammatory pathways are activated in the joint compartment in arthritic conditions. The aim of this study was to characterize the IA haemostatic and inflammatory responses in horses with experimental lipopolysaccharide (LPS)-induced joint inflammation. Inflammation was induced by IA injection of LPS into one antebrachiocarpal joint of six horses. Horses were evaluated clinically with subjective grading of lameness, and blood and synovial fluid (SF) samples were collected at post injection hours (PIH) -120, −96, −24, 0, 2, 4, 8, 16, 24, 36, 48, 72 and 144. Total protein (TP), white blood cell counts (WBC), serum amyloid A (SAA), haptoglobin, iron, fibrinogen, thrombin-antithrombin (TAT) and d-dimer concentrations were assessed in blood and SF.ResultsIntra-articular injection of LPS caused local and systemic signs of inflammation including increased rectal temperature, lameness and increased joint circumference and skin temperature. Most of the biomarkers (TP, WBC, haptoglobin, fibrinogen and TAT) measured in SF increased quickly after LPS injection (at PIH 2–4), whereas SAA and d-dimer levels increased more slowly (at PIH 16 and 144, respectively). SF iron concentrations did not change statistically significantly. Blood WBC, SAA, haptoglobin and fibrinogen increased and iron decreased significantly in response to the IA LPS injection, while TAT and d-dimer concentrations did not change. Repeated pre-injection arthrocenteses caused significant changes in SF concentrations of TP, WBC and haptoglobin.ConclusionSimilar to inflammatory joint disease in humans, joint inflammation in horses was accompanied by an IA haemostatic response with changes in fibrinogen, TAT and d-dimer concentrations. Inflammatory and haemostatic responses were induced simultaneously and may likely interact. Further studies of interactions between the two responses are needed for a better understanding of pathogenesis of joint disease in horses. Knowledge of effects of repeated arthrocenteses on levels of SF biomarkers may be of value when markers are used for diagnostic purposes.

Effects of zinc deficiency on the relevant immune function in rats with sepsis induced by endotoxin/lipopolysaccharide

Effects of zinc deficiency on the relevant immune function in rats with sepsis induced by endotoxin/lipopolysaccharide

Influence of an n-3 long-chain polyunsaturated fatty acid-enriched diet on experimentally induced synovitis in horses.

Dietary n-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation has previously been shown to modify joint-related inflammation in several species, although information in the horse is lacking. We investigated whether dietary supplementation with n-3 LCPUFA would modify experimentally induced synovitis in horses. Twelve, skeletally mature, non-pregnant mares were randomly assigned to either a control diet (CONT) or an n-3 long-chain fatty acid-enriched treatment diet (N3FA) containing 40g/day of n-3 LCPUFA for 91days. Blood samples taken on days 0, 30, 60 and 90, and synovial fluid collected on days 0 and 90 were processed for lipid composition. On day 91, joint inflammation was stimulated using an intra-articular (IA) injection of 100ng of recombinant equine IL-1beta (reIL-1β). Synovial fluid samples taken at post-injection hours (PIH) 0, 4, 8 and 24 were analysed for prostaglandin E2 (PGE2 ), matrix metalloproteinase (MMP) activity and routine cytology. Synovium and articular cartilage samples collected at PIH 8 were analysed for gene expression of MMP 1 and MMP 13, interleukin-1beta (IL-1β), cyclooxygenase 2 (COX-2), tumour necrosis factor-alpha and the aggrecanases, a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5. A 90-day feeding period of n-3 LCPUFA increased serum phospholipid and synovial fluid lipid compositions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to CONT horses. The reIL-1β injection caused an inflammatory response; however, there was no effect of dietary treatment on synovial fluid PGE2 content and MMP activity. Synovial tissue collected from N3FA horses exhibited lower expression of ADAMTS-4 compared to CONT horses. Despite the presence of EPA and DHA in the synovial fluid of N3FA horses, dietary n-3 LCPUFA supplementation did not modify synovial fluid biomarkers compared to CONT horses; however, the lower ADAMTS-4 mRNA expression in N3FA synovium warrants further investigation of n-3 LCPUFA as a joint therapy.

Protective role of γδ T cells in concanavalin A-induced liver injury

To investigate the role played by γδ T cells in acute liver injury using the concanavalin A (ConA)-induced liver injury mouse model. Acute liver injury was induced by intravenous injection of 10 mug/g of ConA into male C57BL/6J mice with wild-type or T cell receptor-γ knockout (TCR δ-/-) genetic backgrounds. Mice injected with PBS alone served as negative controls. The degree of liver damage was assessed by measuring serum levels of transaminase and cytokines at post-injection hours 3, 6, 12, 24, 48, and 72. The percentage of γδ T cells and proportions of different subsets in liver lymphocytes were measured by flow cytometry. The TCR δ-/- mice showed significantly higher levels of the inflammatory cytokines IFN-γ, TNFα and IL-4 than the wild-type mice at post-injection hour 3. The percentage of liver γδ T cells increased with increased injury degree, and the extent of increase was significantly higher in the TCR δ-/- mice than the wild-type mice (post-injection hour 6: 6302.61+/-592.06 vs. 1319.26+/-355.48, 12: 6569.44+/-1060.98 vs. 3415.53+/-343.90, 24: 6514.29+/-757.26 vs. 2062.73+/-365.67, 48: 1262.61+/-558.07 vs. 113.66+/-113.26, and 72: 226.54+/-98.20 vs. 42.35+/-21.51 U/L; all P less than 0.05). In addition, compared to the negative control mice, the ConA-induced mice showed a higher proportions of Vγ4 γδ T cells to total γδ T cells (17.78+/-2.95 vs. 25.26+/-2.43) and to total liver lymphocytes (0.47+/-0.07 vs. 0.66+/-0.05). Similarly, compared to the negative control mice, the ConA-induced mice showed a higher proportion of Vγ1 γδ T cells to total γδ T cells (38.37+/-6.10 vs. 50.19+/-5.52) but the proportion to total liver lymphocytes was not significantly different among the groups (0.76+/-0.18 vs. 0.78+/-0.25). Reinfusion of Vγ4 γδ T lymphocytes into TCR δ-/- mice led to lower serum ALT levels than reinfusion of Vγ1 γδ T lymphocytes (5054.10+/-1748.51 vs. 12333.56+/-663.535 U/L). γδ T cells play a protective role in ConA-induced liver injury and this effect maybe mediated by the Vγ4 γδ T cell subset.

Disc size markedly influences concentration profiles of intravenously administered solutes in the intervertebral disc: a computational study on glucosamine as a model solute

Tests on animals of different species with large differences in intervertebral disc size are commonly used to investigate the therapeutic efficacy of intravenously injected solutes in the disc. We hypothesize that disc size markedly affects outcome. Here, using a small non-metabolized molecule, glucosamine (GL) as a model solute, we calculate the influence of disc size on transport of GL into rat, rabbit, dog and human discs for 10 h post intravenous-injection. We used transient finite element models and considered an identical GL supply for all animals. Huge effects of disc size on GL concentration profiles were found. Post-injection GL concentration in the rat disc reached 70% blood concentration within 15 min but remained below 10% in the human disc nucleus throughout. The GL rapidly penetrated post-injection into smaller discs resulting in homogeneous concentrations. In contrast, GL concentration, albeit at much lower levels, increased with time in the human disc with a small outward flux at the annulus periphery at longer periods. Changes in the disc size hugely influenced GL concentrations throughout the disc at all regions and times. Increases in administered dose can neither remedy the very low concentration levels in the disc center in larger human disc at early post-injection hours nor alter the substantial differences in concentration profiles estimated among various species. The size effect will only be exacerbated as molecular weight of the solute increases and as the endplate calcifies. Extrapolation of findings from animal to human discs on the efficacy of intravenously administered solutes must proceed with great caution.

Evaluation of the inflammatory response in experimentally induced synovitis in the horse: a comparison of recombinant equine interleukin 1 beta and lipopolysaccharide

To compare two transient models of synovitis-osteoarthritis (OA) in horses by characterizing biological changes in synovial fluid and joint tissue. Twelve skeletally mature mares were utilized in a block design. Synovitis was induced by an intra-articular injection of 100ng recombinant equine interleukin 1 beta (reIL-1β) or 0.5ng lipopolysaccharide (LPS) into a middle carpal joint in 1ml volumes. One ml of saline was injected into the contra-lateral control joint. Lameness evaluations were conducted through post-injection hour (PIH) 8 (at which time arthroscopic removal of synovium and articular biopsies was done), and at PIH 240. Arthrocentesis collection of synovial fluid occurred between PIH 0 and 48. An arthroscopic examination at PIH 8 included synovium and articular cartilage biopsies for gene expression analysis. Synovial fluid analysis indicated that single injections of reIL-1β or LPS increased synovial white blood cell (WBC), neutrophil count, total protein, prostaglandin E(2) (PGE(2)) concentrations and general matrix metalloproteinase (MMP) activity relative to control joints through PIH 8. Injections of either reIL-1β or LPS increased mRNA expression for MMP-1 and a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 in synovium and for MMP-1, ADAMTS-4, ADAMTS-5 in articular cartilage collected at PIH 8 compared to saline injections. Injections of reIL-1β into equine carpal joints resulted in a transient inflammatory response that was similar in severity to the LPS injection, causing increased expression of certain deleterious mediators in joint tissues at 8h. Given that IL-1β is a known critical mediator of traumatic arthritis and OA, this humane and temporary model may be useful in evaluating therapeutics that act against early stages of joint disease.

Exenatide enhances kaliuresis under conditions of hyperkalemia

Experiments on Wistar rats showed that exenatide (0.015-0.5 nmol per 100 g body weight) somewhat increased renal excretion of potassium from 7±1 to 16±1 μmol/h/100 g body weight (p<0.05) in animals with normal serum concentration of glucose (4.6±0.4 mM) and potassium (4.3±0.1 mM). Exenatide dramatically enhanced excretion of potassium under conditions of hyperkalemia (11.4±0.4 mM) produced by intraperitoneal injection of 1.25% KCl solution (5 ml per 100 g body weight). During the first postinjection hour, potassium excretion increased 2-fold and attained 97±11 μmol/h/100 g body weight in comparison with potassium load alone (47±9 μmol/h/100 g body weight, p<0.05). The data attest to a possible role of peptide regulators in normalization of potassium balance via renal mechanisms.

Carisbamate acutely suppresses spasms in a rat model of symptomatic infantile spasms

Infantile spasms are the signature seizures of West syndrome. The conventional treatments for infantile spasms, such as adrenocorticotropic hormone (ACTH) and vigabatrin, are not always effective, especially in symptomatic infantile spasms (SIS). We tested the efficacy of carisbamate, a novel neurotherapeutic drug, to suppress spasms in the multiple-hit rat model of SIS, and compared it with phenytoin to determine if its effect is via sodium-channel blockade. Sprague-Dawley rats received right intracerebral infusions of doxorubicin and lipopolysaccharide at postnatal day 3 (PN3) and intraperitoneal p-chlorophenylalanine at PN5. A single intraperitoneal injection of carisbamate was administered at PN4, after the onset of spasms, at the following doses: 10 mg/kg (CRS-10), 30 mg/kg (CRS-30), and 60 mg/kg (CRS-60), and was compared to vehicle-injected group (VEH). Video-monitoring of PN6-7 CRS-60 or VEH-injected pups was also done. Carisbamate acutely reduced both behavioral spasms (CRS-30 and CRS-60 groups only) and electroclinical spasms during the first 2-3 postinjection hours, without detectable toxicity or mortality. In contrast, phenytoin (20 or 50 mg/kg) failed to suppress spasms. Our findings provide preclinical evidence that carisbamate displays acute anticonvulsive effect on spasms through a sodium channel-independent mechanism. Because spasms in the multiple-hit rat model are refractory to ACTH and transiently sensitive to vigabatrin, carisbamate may constitute a candidate new therapy for SIS, including the ACTH-refractory spasms. Further confirmation with clinical studies is needed.

Interleukin-1 Inhibits Putative Cholinergic Neurons in Vitro and REM Sleep when Microinjected into the Rat Laterodorsal Tegmental Nucleus

REM sleep is suppressed during infection, an effect mimicked by the administration of cytokines such as interleukin-1 (IL-1). In spite of this observation, brain sites and neurochemical systems mediating IL-1-induced suppression of REM sleep have not been identified. Cholinergic neurons in the brainstem laterodorsal tegmental nucleus (LDT) are part of the neuronal circuitry responsible for REM sleep generation. Since IL-1 inhibits acetylcholine synthesis and release, the aim of this study was to test the two different, but related hypotheses. We hypothesized that IL-1 inhibits LDT cholinergic neurons, and that, as a result of this inhibition, IL-1 suppresses REM sleep. To test these hypotheses, the electrophysiological activity of putative cholinergic LDT neurons was recorded in a rat brainstem slice preparation. Interleukin-1 significantly inhibited the firing rate of 76% of recorded putative cholinergic LDT neurons and reduced the amplitude of glutamatergic evoked potentials in 60% of recorded neurons. When IL-1 (1 ng) was microinjected into the LDT of freely behaving rats, REM sleep was reduced by about 50% (from 12.7% +/- 1.5% of recording time [after vehicle] to 6.1% +/- 1.4% following IL-1 administration) during post-injection hours 3-4. Results of this study support the hypothesis that IL-1 can suppress REM sleep by acting at the level of the LDT nucleus. Furthermore this effect may result from the inhibition of evoked glutamatergic responses and of spontaneous firing of putative cholinergic LDT neurons.

In vivoeffects of meloxicam on inflammatory mediators, MMP activity and cartilage biomarkers in equine joints with acute synovitis

Meloxicam is a commonly used nonsteroidal anti-inflammatory drug in equine practice, but little is known about its in vivo effects on joint inflammation and cartilage turnover. To study the effects of meloxicam on biomarkers of inflammation, matrix metalloproteinase (MMP) activity, and cartilage biomarkers in joints with experimental synovitis. In a 2-period cross-over study, synovitis was induced at T = 0 h in the L or R intercarpal joint of 6 horses by intraarticular injection of 0.5 ng lipopolysaccharide (LPS). Horses received once daily meloxicam (0.6 mg/kg bwt per os) or placebo starting at post injection hour (PIH) 2, and clinical evaluations as well as blood and synovial fluid (SF) sampling were performed at PIH 0, 8, 24 and 168. Synovial fluid was analysed for prostaglandin E2, bradykinin, substance P, general MMP activity, glycosaminoglycans (GAG), CS846 epitope, type II collagen cleavage fragments (C2C) and type II collagen carboxypropeptide (CPII). Concentrations in meloxicam- vs. placebo-treated joints over time were compared using a linear mixed model. Lipopolysaccharide injection caused marked transient synovitis without systemic effects. Meloxicam caused a significant reduction in lameness at PIH 8 and 24 and tended to reduce effusion. In addition, meloxicam significantly suppressed SF prostaglandin E2 and substance P release at PIH 8 and bradykinin at PIH 24 compared to placebo treatment. General MMP activity at PIH 8 and 24 was significantly lower in meloxicam- vs. placebo-treated joints, as were GAG, C2C and CPII concentrations at PIH 24. Acute transient synovitis leads to substantial increases in SF biomarkers of inflammation, MMP activity and cartilage turnover, which can be significantly suppressed by meloxicam. Early oral treatment with meloxicam ameliorates not only clinical signs and joint inflammation in acute synovitis, but may also limit inflammation-induced cartilage catabolism.

Inflammatory mediators and cartilage biomarkers in synovial fluid after a single inflammatory insult: a longitudinal experimental study

IntroductionInflammation is an important feature of many joint diseases, and levels of cartilage biomarkers measured in synovial fluid may be influenced by local inflammatory status. Little is known about the magnitude and time course of inflammation-induced changes in cartilage tissue turnover as measured in vivo by synovial fluid markers. We aimed to study temporal changes in concentrations of inflammatory mediators, matrix metalloproteinase activity and cartilage biomarkers over 1 week in joints with experimentally induced inflammation.MethodsLocalized inflammation was induced in the intercarpal joint of six horses by sterile injection of 0.5 ng lipopolysaccharide, and synovial fluid was collected at post-injection hours (PIH) 0, 8, 24 and 168. Concentrations of inflammatory mediators (prostaglandin E2, substance P, and bradykinin), general matrix metalloproteinase activity and markers of collagen II turnover (CPII and C2C) as well as aggrecan turnover (CS846 and glycosaminoglycans) were measured with appropriate assays. One-way analysis of variance on repeated measures was used to analyze differences in synovial fluid marker levels over time.ResultsLipopolysaccharide-injection led to a sharp rise in prostaglandin E2 at PIH 8, while substance P, bradykinin and matrix metalloproteinase activity showed more sustained increases at PIH 8 and 24. Glycosaminoglycan release paralleled changes in the CS846 epitope, with an increase by PIH 8, a peak at PIH 24, and return to baseline by PIH 168. For type II collagen, a parallel time course between catabolic (C2C) and anabolic (CPII) markers was also observed, but the time course differed from that seen for proteoglycan markers: collagen II markers peaked later, at PIH 24, and were still elevated over baseline at PIH 168.ConclusionsA primary intra-articular inflammatory insult, characterized by local release of peptide and lipid mediators and matrix metalloproteinase activation, can alter synovial fluid levels of proteoglycan biomarkers as early as 8 hours post-induction, and can lead to sustained rises in collagen II biomarkers during at least 1 week after onset.

Delayed Satiety-Like Actions and Altered Feeding Microstructure by a Selective Type 2 Corticotropin-Releasing Factor Agonist in Rats: Intra-Hypothalamic Urocortin 3 Administration Reduces Food Intake by Prolonging the Post-Meal Interval

Brain corticotropin-releasing factor/urocortin (CRF/Ucn) systems are hypothesized to control feeding, with central administration of 'type 2' urocortins producing delayed anorexia. The present study sought to identify the receptor subtype, brain site, and behavioral mode of action through which Ucn 3 reduces nocturnal food intake in rats. Non-food-deprived male Wistar rats (n=176) were administered Ucn 3 into the lateral (LV) or fourth ventricle, or into the ventromedial or paraventricular nuclei of the hypothalamus (VMN, PVN) or the medial amygdala (MeA), regions in which Ucn 3 is expressed in proximity to CRF(2) receptors. LV Ucn 3 suppressed ingestion during the third-fourth post-injection hours. LV Ucn 3 anorexia was reversed by cotreatment with astressin(2)-B, a selective CRF(2) antagonist and not observed following equimole subcutaneous or fourth ventricle administration. Bilateral intra-VMN and intra-PVN infusion, more potently than LV infusion, reduced the quantity (57-73%) and duration of ingestion (32-68%) during the third-fourth post-infusion hours. LV, intra-PVN and intra-VMN infusion of Ucn 3 slowed the eating rate and reduced intake by prolonging the post-meal interval. Intra-VMN Ucn 3 reduced feeding bout size, and intra-PVN Ucn 3 reduced the regularity of eating from pellet to pellet. Ucn 3 effects were behaviorally specific, because minimal effective anorectic Ucn 3 doses did not alter drinking rate or promote a conditioned taste aversion, and site-specific, because intra-MeA Ucn 3 produced a nibbling pattern of more, but smaller meals without altering total intake. The results implicate the VMN and PVN of the hypothalamus as sites for Ucn 3-CRF(2) control of food intake.