Bupivacaine???s Action on the Carrageenan-Induced Inflammatory Response in Mice: Cytokine Production by Leukocytes After Ex-Vivo Stimulation

Bupivacaine inhibits the TLR4- and TLR2-Myd88/NF-κB pathways in human leukocytes

Local anesthetics have anti-inflammatory effects. Because most previous experiments were performed with supra-therapeutic concentrations, we measured the effects of clinically relevant concentrations of bupivacaine on the Toll like receptor 4 (TLR4)- and TLR2-myeloid differentiation primary response 88 (MyD88)-nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB) pathways. We measured tumor necrosis factor alpha (TNF-α) and prostaglandin E2 (PGE2) release, p38 mitogen-activated protein kinase (MAP-kinase) phosphorylation and translocation of NF-κB in human peripheral blood mononuclear cells (hPBMCs) and human monocytes challenged with lipopolysaccharide (LPS) or tripalmitoylated lipopeptide Pam3CysSerLys4 (Pam3CSK4) in the presence or absence of bupivacaine. Similarly, we measured the effect of bupivacaine on HEK293 cells expressing the hTLR4 and the hTLR2 genes and challenged with LPS or Pam3CSK4. Finally, molecular docking simulations of R(+)- and S(-)-bupivacaine binding to the TLR4-myeloid differentiation protein 2 (MD-2) complex and to the TLR2/TLR1 heterodimer were performed. In PBMCs, bupivacaine from 0.1 to 100 μM inhibited LPS-induced TNF-α and PGE2 secretion, phosphorylation of p38 and nuclear translocation of NF-κB in monocytes. Bupivacaine similarly inhibited the effects of Pam3CSK4 on TNF-α secretion. Bupivacaine inhibited the effect of LPS on HEK293 cells expressing the human TLR4 receptor and the effect of Pam3CSK4 on HEK293 cells expressing the human TLR2 receptor. Molecular docking showed that bupivacaine binds to the MD-2 co-receptor of TLR4 and to the TLR2 receptor. Contrary to numerous experiments performed with supratherapeutic doses, our results were obtained with concentrations of bupivacaine as low as 0.1 μM. We conclude that bupivacaine modulates the inflammatory reactions such as those observed after surgery or trauma, at least partly by inhibiting the TLR4- and TLR2-NF-κB pathways.

Regional anesthesia did not improve postoperative long-term survival of tumor patients: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Experimental research and clinical trials have reported a positive effect of regional anesthesia (RA) on prognosis of cancers. We systematically reviewed the efficacy of RA on recurrence-free survival (RFS) and overall survival (OS) after oncology surgeries.

METHODS

PubMed, Cochrane library, and Embase were searched from inception to June 20, 2022 for RCTs in which any form of RA was initiated perioperatively. Time-to-event data (hazard ratio (HR)) were extracted independently and in duplicate. The primary outcome was the association of RA with RFS and OS, while the secondary outcomes included time to tumor progression, 5-year RFS, and 5-year OS.

RESULTS

Fifteen RCTs with 5981 participants were included. Compared to GA, RA has no positive effect on RFS (HR, - 0.02; 95% CI, - 0.11 to 0.07), OS (HR, - 0.03; 95% CI, - 0.28 to 0.23), time to tumor progression (0.11; 95% CI, - 0.33 to 0.55), 5-year RFS (risk ratio (RR), 1.24; 95% CI, 0.88 to 1.76)), and 5-year OS (RR, 1.11; 95% CI, 0.85 to 1.44). Subgroup analysis based on study design, patient characteristics and tumor types also showed no effect of RA on RFS or OS.

CONCLUSIONS

Our results demonstrated that there is no significant evidence supporting the role of RA in improving long-term survival after oncology surgeries.

Antinociceptive effects of bupivacaine and its sulfobutylether-β-cyclodextrin inclusion complex in orofacial pain

Bupivacaine hydrochloride (BVC) represents an option to produce long-lasting analgesia, and complexation in cyclodextrins has shown improvements in biopharmaceutical properties. This study aimed to characterize and test the cytotoxicity and antinociceptive effects of BVC complexed in sulfobutylether-β-cyclodextrin (SBEβCD). The kinetics and stoichiometry of complexation and BVC-SBEβCD association constant were evaluated by phase solubility study and Job's plot. Evidence of the BVC-SBEβCD complex formation was obtained from scanning electron microscopy (SEM), infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The cytotoxicity was evaluated in keratinocyte (HaCaT) and neuroblastoma (SH-SY5Y). Antinociceptive effects were registered via orofacial pain models: the formalin test, carrageenan-induced hyperalgesia, and postoperative pain (intraoral incision). The complex formation occurred at a 1:1 BVC-SBEβCD molar ratio, with a low association constant (13.2 M^-1). SEM, DSC, and FTIR results demonstrated the host-guest interaction. The IC_50% values determined in SH-SY5Y were 216 µM and 149 µM for BVC and BVC-SBEβCD, respectively (p < 0.05). There was no difference in HaCaT IC_50%. In orofacial pain model, BVC-SBEβCD significantly prolonged antinociceptive effect, in about 2 h, compared to plain BVC. SBEβCD can be used as a drug delivery system for bupivacaine, whereas the complex showed long-lasting analgesic effects.

Acute Visceral Pain in Rats: Vagal Nerve Block Compared to Bupivacaine Administered Intramuscularly

BACKGROUND

Visceral and parietal peritoneum layers have different sensory innervations. Most visceral peritoneum sensory information is conveyed via the vagus nerve to the nucleus of the solitary tract (NTS). We already showed in animal models that intramuscular (i.m.) injection of local anesthetics decreases acute somatic and visceral pain and general inflammation induced by aseptic peritonitis. The goal of the study was to compare the effects of parietal block, i.m. bupivacaine, and vagotomy on spinal cord and NTS stimulation induced by a chemical peritonitis.

METHODS

We induced peritonitis in rats using carrageenan and measured cellular activation in spinal cord and NTS under the following conditions, that is, a parietal nerve block with bupivacaine, a chemical right vagotomy, and i.m. microspheres loaded with bupivacaine. Proto-oncogene c-Fos (c-Fos), cluster of differentiation protein 11b (CD11b), and tumor necrosis factor alpha (TNF-α) expression in cord and NTS were studied.

RESULTS

c-Fos activation in the cord was inhibited by nerve block 2 hours after peritoneal insult. Vagotomy and i.m. bupivacaine similarly inhibited c-Fos activation in NTS. Forty-eight hours after peritoneal insult, the number of cells expressing CD11b significantly increased in the cord (P = .010). The median difference in the effect of peritonitis compared to control was 30 cells (CI95, 13.5-55). TNF-α colocalized with CD11b. Vagotomy inhibited this microglial activation in the NTS, but not in the cord. This activation was inhibited by i.m. bupivacaine both in cord and in NTS. The median difference in the effect of i.m. bupivacaine added to peritonitis was 29 cells (80% increase) in the cord and 18 cells (75% increase) in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli by inhibiting c-Fos and microglia activation.

CONCLUSIONS

In rats receiving intraperitoneal carrageenan, i.m. bupivacaine similarly inhibited c-Fos and microglial activation both in cord and in the NTS. Vagal block inhibited activation only in the NTS. Our study underlines the role of the vagus nerve in the transmission of an acute visceral pain message and confirmed that systemic bupivacaine prevents noxious stimuli. This emphasizes the effects of systemic local anesthetics on inflammation and visceral pain.

Cannabis roots: Pharmacological and toxicological studies in mice

ETHNOPHARMACOLOGICAL RELEVANCE

There are many studies and therapeutic properties attributed to the flowers and leaves of the Cannabis species, but even with few pharmacological studies, Cannabis sativa L. (Cannabaceae) roots presents several therapeutic indications in folk medicine.

AIM OF THE STUDY

This study aimed to evaluate the anti-inflammatory and spasmolytic effects as well as the toxicological profile of the aqueous extract of Cannabis sativa roots (CsAqEx) in mice.

MATERIALS AND METHODS

We assessed the anti-inflammatory effect with carrageenan-induced leukocyte migration assay, and carrageenan and histamine-induced paw edema methods; The spasmolytic effect was assessed through in vitro assays with isolated mice trachea. To assess motor coordination and mobility, mice went through the rotarod and open field tests, respectively. For the single-dose toxicity study, we administered CsAqEx at the dose of 1000 mg/kg by gavage. In a repeated dose toxicity study, animals received CsAqEx at doses of 25 mg or 100 mg/kg for 28 days.

RESULTS

The CsAqEx inhibited the migration of leukocytes at the doses of 25, 50, and 100 mg/kg. The CsAqEx showed anti-inflammatory activity after the intraplantar injection of carrageenan, presenting a reduction in edema formation at all tested doses (12.5, 25, 50 and 100 mg/kg). The dose of 12.5 mg/kg of CsAqEx prevented edema formation after intraplantar injection of histamine. In an organ bath, 729 μg/mL of CsAqEx did not promote spasmolytic effect on isolated mice tracheal rings contracted by carbachol (CCh) or potassium chloride (KCl). We did not observe clinical signs of toxicity in the animals after acute treatment with CsAqEx, which suggested that the median lethal dose (LD₅₀) is greater than 1000 mg/kg. Repeated dose exposure to the CsAqEx did not produce significant changes in hematological, biochemical, or organ histology parameters.

CONCLUSIONS

The results suggest that the anti-inflammatory effect of CsAqEx is related to the reduction of vascular extravasation and migration of inflammatory cells, without effects on the central nervous system. Moreover, there was no spasmolytic effect on airway smooth muscle and no toxicity was observed on mice.

Parietal Block Using Bupivacaine in the Rat: An Anatomical, Behavioral and Histological Study

Purpose

Animal models of regional anaesthesia are useful for studying the effects of blocks and improve their efficacy. The aim of our experiments was to validate a multi-site paravertebral block in the rat.

Material and methods

Dissection and indigo carmine dye injection were performed in five rats (3 rats were dissected and 2 were dye injected). In other groups (n=7rats/group), after inflammation inductive carrageenan injection in the abdominal wall, bupivacaine or saline was injected laterally to the spinal column at the T5, T10, L1, L4 and S1 level. The efficacy of the block on mechanical nociception was measured using von Frey hairs. In addition, we measured c-Fos immunoreactive nuclei in the cord.

Results

The multi-site injection showed a perinervous distribution of the injected solution without intra-thoracic, intra-abdominal or epidural diffusion. Bilateral block with a relatively small volume of bupivacaine (0.5 mL) significantly increased the threshold to mechanical pain as compared to control (p=0.007) and significantly decreased the number of c-Fos immunoreactive nuclei in the posterior horn of the spinal cord (p<0.0001).

Conclusion

This study shows that a parietal abdominal wall block is easy to perform in the rat. This block allows investigators to explore the mechanisms of action of abdominal parietal wall blocks.

Postoperative Regional Analgesia Is Effective in Preserving Perforin-Expressing Lymphocytes in Patients After Total Knee Replacement

BACKGROUND Pain and surgical stress cause a pro-inflammatory response followed by downregulation of the immune response, which can increase the incidence of postoperative complications, such as infections or prolonged wound healing. T lymphocytes and natural killer (NK) cells have cytotoxic potential and are crucial components of cellular immunity, which is important for maintenance of immune balance. The aim of this study was to analyze the effects of 3 types of postoperative analgesia on the preservation and cytotoxic potential of T lymphocytes, NK cells, and their subpopulations, as well as NKT cells, in patients after total knee replacement (TKR) to find the most effective analgesic technique for mitigating immune suppression. MATERIAL AND METHODS Forty-eight patients scheduled for TKR were randomly allocated to Group 1 (patients received epidural analgesia), Group 2 (patients received sciatic and femoral nerve block), or Group 3 (patients received multimodal systemic analgesia). Pain intensity was assessed at rest and on movement before, immediately after, and at 24 and 72 h after surgery. Blood samples were collected at the same time points and peripheral blood mononuclear cells were isolated. The frequencies of T lymphocytes, NK cells, and NKT cells, as well as their perforin expression, were simultaneously detected and analyzed by flow cytometry. RESULTS Patients in Group 1 and Group 2 experienced less severe pain than those in Group 3. The frequencies and perforin levels of T lymphocytes, their subsets, and NKT cells were significantly lower in Group 3 than in Group 1 and Group 2. CONCLUSIONS The present study confirmed that regional analgesia is more effective in maintaining cell-mediated immunity and perforin expression in peripheral blood lymphocytes in patients after TKR.

Impact of Preemptive Analgesia on inflammatory responses and Rehabilitation after Primary Total Knee Arthroplasty: A Controlled Clinical Study

The aim of this study was to investigate the effects of preemptive analgesia on the inflammatory response and rehabilitation in TKA. 75 patients with unilateral primary knee osteoarthritis were conducted in this prospective study. All patients were randomly divided into two groups (MMA with/without preemptive analgesia group). The following parameters were used to evaluate analgesic efficacy: knee flexion, pain at rest and walking, functional walking capacity (2 MWT and 6 MWT), WOMAC score, and hs-CRP level. Patients in MMA with preemptive analgesia group had lower hs-CRP level and less pain at rest and walking during the first week postoperatively (P < 0.05). The 2 MWT was significantly better in MMA with preemptive analgesia group (17.13 ± 3.82 VS 14.19 ± 3.56, P = 0.001). The 6 MWT scores and WOMAC scores increased significantly within Groups (P = 0.020, 0.000), but no difference between groups postoperatively (P > 0.05). Less cumulative consumption of morphine was found in MMA with preemptive analgesia group at 48 h (P = 0.017, 0.023), but no difference at total requirement (P = 0.113). Preemptive analgesia added to a multimodal analgesic regime improved analgesia, reduced inflammatory reaction and accelerated functional recovery at the first week postoperatively, but not improved long-term function.

Perioperative cerebrospinal fluid and plasma inflammatory markers after orthopedic surgery

Background

Postoperative delirium is prevalent in older patients and associated with worse outcomes. Recent data in animal studies demonstrate increases in inflammatory markers in plasma and cerebrospinal fluid (CSF) even after aseptic surgery, suggesting that inflammation of the central nervous system may be part of the pathogenesis of postoperative cognitive changes. We investigated the hypothesis that neuroinflammation was an important cause for postoperative delirium and cognitive dysfunction after major non-cardiac surgery.

Methods

After Institutional Review Board approval and informed consent, we recruited patients undergoing major knee surgery who received spinal anesthesia and femoral nerve block with intravenous sedation. All patients had an indwelling spinal catheter placed at the time of spinal anesthesia that was left in place for up to 24 h. Plasma and CSF samples were collected preoperatively and at 3, 6, and 18 h postoperatively. Cytokine levels were measured using ELISA and Luminex. Postoperative delirium was determined using the confusion assessment method, and cognitive dysfunction was measured using validated cognitive tests (word list, verbal fluency test, digit symbol test).

Results

Ten patients with complete datasets were included. One patient developed postoperative delirium, and six patients developed postoperative cognitive dysfunction. Postoperatively, at different time points, statistically significant changes compared to baseline were present in IL-5, IL-6, I-8, IL-10, monocyte chemotactic protein (MCP)-1, macrophage inflammatory protein (MIP)-1α, IL-6/IL-10, and receptor for advanced glycation end products in plasma and in IFN-γ, IL-6, IL-8, IL-10, MCP-1, MIP-1α, MIP-1β, IL-8/IL-10, and TNF-α in CSF.

Conclusions

Substantial pro- and anti-inflammatory activity in the central neural system after surgery was found. If confirmed by larger studies, persistent changes in cytokine levels may serve as biomarkers for novel clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12974-016-0681-9) contains supplementary material, which is available to authorized users.

The Effects of Perioperative Regional Anesthesia and Analgesia on Cancer Recurrence and Survival After Oncology Surgery: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVES

Potentially, perioperative regional anesthesia and analgesia (RA) could influence the outcomes of patients with cancer. The aim of this systematic review and meta-analysis was to evaluate the effects of perioperative RA on survival and cancer recurrence after oncologic surgery.

METHODS

The authors searched computerized databases (from inception to December 2014) and reference lists and considered all studies comparing the effects of RA on cancer recurrence or overall survival with that of general anesthesia (GA). Risk estimates were pooled to determine the effects of RA on risks of cancer recurrence and mortality. Twenty eligible studies were included.

RESULTS

Perioperative RA use was associated with improved overall survival (Hazard ratio [HR] = 0.84, 95% CI, 0.75 - 0.94; I =41%), but not with reduced cancer recurrence (HR=0.91, 95% CI, 0.70 - 1.18; I=83%).

CONCLUSIONS

Our meta-analysis suggests that RA may improve overall survival but not reduce cancer recurrence after oncologic surgery.

Effects of Astaxanthin from Litopenaeus Vannamei on Carrageenan-Induced Edema and Pain Behavior in Mice

Carrageenan produces both inflammation and pain when injected in mouse paws via enhancement of reactive oxygen species formation. We have investigated an effect of astaxanthin extracted from Litopenaeus vannamei in carrageenan-induced mice paw edema and pain. The current study demonstrates interesting effects from astaxanthin treatment in mice: an inhibition of paw edema induced in hind paw, an increase in mechanical paw withdrawal threshold and thermal paw withdrawal latency, and a reduction in the amount of myeloperoxidase enzyme and lipid peroxidation products in the paw. Furthermore the effect was comparable to indomethacin, a standard treatment for inflammation symptoms. Due to adverse effects of indomethacin on cardiovascular and gastrointestinal systems, our study suggests promising prospect of astaxanthin extract as an anti-inflammatory alternative against carrageenan-induced paw edema and pain behavior.

Anti-inflammatory and anti-hyperalgesic effect of all-trans retinoic acid in carrageenan-induced paw edema in Wistar rats: involvement of peroxisome proliferator-activated receptor-β/δ receptors

Objective:

In this study, we investigated the role of peroxisome proliferator-activated receptors (PPAR)-β/δ receptors in carrageenan-induced inflammation and in the anti-inflammatory effects of all-trans retinoic acid (ATRA).

Materials and Methods:

The λ-carrageenan (0.1 ml of 1% w/v) was injected into intra-plantar (i.pl.) region of the hind paw to produce acute inflammation. Paw volume was measured by using the mercury plethysmography. Further, mechanical and thermal hyperalgesia (TH) were assessed by using the dynamic plantar aesthesiometer and plantar test apparatus, respectively. In addition, markers of oxido-nitrosative stress were assessed spectrophotometrically in the hind paw tissue 5 h post-carrageenan.

Results:

An i.pl injection of carrageenan has produced a marked mechanical hyperalgesia (MH) and TH in ipsilateral paw, which was associated with significant elevated oxido-nitrosative stress. Treatment with ATRA (5 mg/kg/p.o/4 days) and GW0742, a selective PPAR-β/δ receptor agonist (0.1 mg/kg/i.p/4 days), significantly decreased the paw volume, mechanical and TH as compared to vehicle control. Administration of GSK0660, selective PPAR-β/δ receptor antagonist, at a dose of (0.3 mg/kg/i.p/4 days), did not produce a significant effect on carrageenan-induced paw edema, MH and TH. However, co-administration of GSK0660 (0.3 mg/kg/i.p/4 days) along with both ATRA (5 mg/kg/p.o/4 days) and GW0742 (0.1 mg/kg/i.p/4 days), significantly reverse the decreased paw edema, MH, and TH. These observed ameliorative effects on inflammatory pain symptoms are correlated with the extent of reduction of oxido-nitrosative stress.

Conclusion:

From above findings, it can be concluded that ATRA exerts anti-inflammatory and anti-hyperalgesic effect, possibly through activation of PPAR-β/δ and subsequent reduction of oxido-nitrosative stress.

Cnidoscolus chayamansa Mc Vaugh, an important antioxidant, anti-inflammatory and cardioprotective plant used in Mexico

ETHNOPHARMACOLOGICAL RELEVANCE

Cnidoscolus chayamansa Mc Vaugh (Euphorbiaceae) is commonly known as 'chaya' in Central America. In South East Mexico, because of its high nutritional values, is an important part of the diet of many indigenous communities. Chaya is also used as a traditional remedy for the treatment of diabetes, rheumatism, gastrointestinal disorders and inflammation-related diseases. Although Cnidoscolus chayamansa is one of most used and valued medicinal plants, only few studies on documenting its pharmacological properties can be found.

MATERIALS AND METHODS

Dried leaves of Cnidoscolus chayamansa were subjected to a successive maceration using Hex, EtOAc and EtOH. The antioxidant activities of the extracts were tested using the DPPH radical scavenging, Ferric reducing/antioxidant power and total phenolic content assays. To determine the anti-inflammatory activity, the TPA-induced mouse ear edema and the carrageenan-induced mouse paw edema assays were used. The cardioprotective effects of the EtOH extract was determined using the ischemia/reperfusion (I/R) rat model. Finally, the acute toxicity was determined using Lorke's method.

RESULTS

The results showed a similar anti-inflammatory activity (≈30%) for all extracts but only the EtOAc extract showed relevant activity when applied intraperitoneally. When tested for their antioxidant activity none of the extracts showed a significant activity suggesting that the antinflammatory activity is not related to a direct free radical scavenging of the extracts. Additionally, the EtOH extract showed a strong cardioprotective effect at 500mg/kg when given orally. Both the EtOAc and the EtOH extract have a LD50 >5g/kg, confirming their safety in acute oral administration.

CONCLUSIONS

All these results are relevant for a better understanding of the therapeutic used of Cnidoscolus chayamansa in the Mexican traditional medicine and highlights its cardioprotective potential.

Major abdominal surgery for cancer: does epidural analgesia have a long-term effect on recurrence-free and overall survival?

BACKGROUND

Retrospective studies have suggested that regional analgesia combined with general anaesthesia could decrease cancer recurrence. The purpose of this study was to assess the influence of regional analgesia on recurrence-free (RFS) and overall survival in patients undergoing major intra-abdominal surgery for cancer.

METHOD

Patients previously included in a prospective randomized study comparing two postoperative techniques of analgesia were retrospectively studied. The EP group received general anaesthesia with bupivacaine thoracic epidural analgesia and the SC group received general anaesthesia with fentanyl followed by continuous subcutaneous morphine.

RESULTS

One hundred and thirty-two patients were analyzed (63 and 69 in SC and EP group, respectively) with a 17-year-median follow-up. After 5 years, RFS was 43% [95% CI: 32%-55%] in EP group and 24% [95% CI: 15%-36%] in SC group, but the difference did not reach statistical significance for RFS nor for overall survival (P=0.10 and 0.16 respectively). Using multivariable analysis over the whole follow-up period, the type of analgesia was not a statistically significant predictive factor for RFS (EP/SC, HR=1.3 [95% CI: 0.8-2.0%]). The anaesthesia effect changed moderately over the follow-up and HR for overall survival (EP/SC) reached statistical significance after 5, 6 and 8 years.

CONCLUSION

Despite a trend in favour of the epidural, this retrospective review of patients included in a previous randomized study failed to demonstrate a statistically significant association between the perioperative analgesia and RFS after abdominal surgery for cancer. The duration of follow-up may have an impact on the analgesia effect on survival.

Telaprevir with peginterferon and ribavirin for treatment-naive patients chronically infected with HCV of genotype 1 in Japan

BACKGROUND & AIMS

To evaluate the efficacy and safety of telaprevir in combination with peginterferon-α2b (PEG-IFN) and ribavirin (RBV) in patients with chronic hepatitis C.

METHODS

In a multi-center randomized clinical trial in Japan, on patients infected with HCV of genotype 1, 126 patients were assigned to telaprevir for 12 weeks along with PEG-IFN and RBV for 24 weeks (Group A), while 63 to PEG-IFN and RBV for 48 weeks (Group B).

RESULTS

HCV RNA disappeared more swiftly in patients in Group A than B, and the frequency of patients without detectable HCV RNA at week 4 (rapid virological response (RVR)) was higher in Group A than B (84.0% vs. 4.8%, p <0.0001). Grade 3 and 4 skin disorders, including Stevens-Johnson syndrome and drug rashes with eosinophilia and systemic symptoms, as well as Grade 3 anemia (<8.0 g/dl), occurred more frequently in Group A than B (skin disorders, 11.9% vs. 4.8%; anemia, 11.1% vs. 0.0%). The total RBV dose was smaller in Group A than B (47.0% vs. 77.7% of the target, p <0.0001). Despite these drawbacks, sustained virological response (SVR) was achieved more frequently in Group A than B (73.0% vs. 49.2%, p=0.0020).

CONCLUSIONS

Although the triple therapy with telaprevir-based regimen for 24 weeks resulted in more adverse events and less total RBV dose than PEG-IFN and RBV for 48 weeks, it was able to achieve higher SVR within shorter duration by carefully monitoring adverse events and modifying the RBV dose as required.

Local anesthetics and their adjuncts

Local anesthetics (LA) block propagation of impulses along nerve fibers by inactivation of voltage-gated sodium channels, which initiate action potentials (1). They act on the cytosolic side of phospholipid membranes. Two main chemical compounds are used, amino esters and amino amides. Amino esters are degraded by pseudocholinesterases in plasma. Amino amides are metabolized exclusively by the liver. Only amide LAs will be considered in this article.

The antinociceptive and anti-inflammatory effects of Salvia officinalis leaf aqueous and butanol extracts

CONTEXT

The leaf of sage Salvia officinalis L. (Lamiaceae) is reputed in the folk medicine of Arabia, and Jordan in particular, to relieve pain associated with gastrointestinal disturbance.

OBJECTIVES

Evaluation of the antinociceptive and anti-inflammatory activities of aqueous and butanol extracts of S. officinalis leaf.

MATERIALS AND METHODS

The analgesic effects of the aqueous extract (10, 31.6, 100, 316, 1000 mg/kg) and butanol extract (10, 31.6, 100, 316 mg/kg) were studied using the hot-plate test for mice and the formalin-induced paw licking in rats. The effects were compared to those of morphine and the influence of naloxone on these effects was also evaluated. The same concentrations of both extracts were used to evaluate their anti-inflammatory effects using the cotton pellet granuloma and carrageenan-induced paw edema in rats.

RESULTS

The aqueous extract (10, 31.6, 100, 316, 1000 mg/kg) and butanol extract (10, 31.6, 100, 316 mg/kg) caused analgesic effect in the hot-plate latency assay as well as in early and late phases of formalin-induced paw licking in rats. These effects were reduced by the opioid receptor antagonist, naloxone (5 mg/kg). The same range of doses of both extracts caused dose-dependent inhibition of carrageenan-induced paw edema in rats as well as inhibition of cotton pellet granuloma.

DISCUSSION AND CONCLUSION

These observations suggest that the sage leaf aqueous and butanol extracts have analgesic and anti-inflammatory effects, confirming the traditional use of this plant for pain alleviation.

Effects of a bupivacaine nerve block on the axonal transport of Tumor Necrosis Factor-alpha (TNF-alpha) in a rat model of carrageenan-induced inflammation

Many pro-inflammatory cytokines are involved in the process of inflammatory pain. Bi directional axonal transport of Tumor Necrosis Factor-alpha (TNF-alpha) occurs in case of neuropathic pain induced by nerve ligation. We used an in vivo preparation with injection of carrageenan and fluorescent TNF-alpha in the territory of the saphenous nerve of rats to study this transport. We have shown that retrograde transport of TNF-alpha occurs after an inflammatory insult caused by the injection of carrageenan. This transport was likely mediated by the TNF receptor 1. A nerve block with bupivacaine totally abolishes the expression of the receptor in the dorsal root ganglion and the retrograde transport of TNF-alpha. In addition, bupivacaine at low concentrations (1-10 microM) was able to stop the axonal transport ex vivo. Tetrodotoxin was less efficacious for inhibiting the TNF-alpha transport and the rise in receptor expression and for inhibiting the axonal transport ex vivo. This may partly explain the efficacy of nerve blocks with bupivacaine to decrease the neurogenic inflammation and in a lower extent the long-term inhibition of hyperalgesic phenomenon observed in animals and in humans.

Characterization of protein tyrosine phosphatase H1 knockout mice in animal models of local and systemic inflammation

Background

PTPH1 is a protein tyrosine phosphatase expressed in T cells but its effect on immune response is still controversial. PTPH1 dephosphorylates TCRzeta in vitro, inhibiting the downstream inflammatory signaling pathway, however no immunological phenotype has been detected in primary T cells derived from PTPH1-KO mice. The aim of the present study is to characterize PTPH1 phenotype in two in vivo inflammatory models and to give insights in possible PTPH1 functions in cytokine release.

Methods

We challenged PTPH1-KO mice with two potent immunomodulatory molecules, carrageenan and LPS, in order to determine PTPH1 possible role in inflammatory response in vivo. Cytokine release, inflammatory pain and gene expression were investigated in challenged PTPH1-WT and KO mice.

Results

The present study shows that carrageenan induces a trend of slightly increased spontaneous pain sensitivity in PTPH1-KO mice compared to WT (wild-type) littermates, but no differences in cytokine release, induced pain perception and cellular infiltration have been detected between the two genotypes in this mouse model. On the other hand, LPS-induced TNFα, MCP-1 and IL10 release was significantly reduced in PTPH1-KO plasma compared to WTs 30 and 60 minutes post challenge. No cytokine release modulation was detectable 180 minutes post LPS challenge.

Conclusion

In conclusion, the present study points out a slight potential role for PTPH1 in spontaneous pain sensitivity and it indicates that this phosphatase might play a role in the positive regulation of the LPS-induced cytokines release in vivo, in contrast to previous reports indicating PTPH1 as potential negative regulator of immune response.

[Effect of local anesthetics on the postoperative inflammatory response]

Current knowledge suggests that peripheral inflammation following surgery activates and sensitizes both peripheral and central nervous system. These phenomena involved in the maintenance of the inflammatory response lead to hypersensibility, hyperalgesia and allodynia. Hyperalgesia participates in the general experience of postoperative pain and ALo in the development of chronic pain. A correlation between the ability of treatments to reduce areas of hypersensitivity surrounding the wound after surgery and their ability to reduce the incidence of chronic pain has been shown. For a long time, local anaesthetics have been used for their capacity to block nociceptive input. They can ALo modulate the inflammatory response following a surgical trauma. By inhibiting the nervous conductivity at the site of the trauma, local anesthetics attenuate the sensitization of the nervous system and therefore the inflammatory phenomena. They ALo exert intrinsic anti-inflammatory properties by modulating the local and systemic liberation of inflammatory mediators. The mechanisms involved are not clearly elucidated. Local, systemic, and spinal inflammatory mechanisms may be influenced by local anesthetics through multiple different mechanisms. The therapeutic implications of effects of local anesthetics on local, systemic, and spinal inflammatory responses merit further study.

The differential effects of bupivacaine and lidocaine on prostaglandin E2 release, cyclooxygenase gene expression and pain in a clinical pain model

BACKGROUND

In addition to blocking nociceptive input from surgical sites, long-acting local anesthetics might directly modulate inflammation. In the present study, we describe the proinflammatory effects of bupivacaine on local prostaglandin E2 (PGE2) production and cyclooxygenase (COX) gene expression that increases postoperative pain in human subjects.

METHODS

Subjects (n = 114) undergoing extraction of impacted third molars received either 2% lidocaine or 0.5% bupivacaine before surgery and either rofecoxib 50 mg or placebo orally 90 min before surgery and for the following 48 h. Oral mucosal biopsies were taken before surgery and 48 h after surgery. After extraction, a microdialysis probe was placed at the surgical site for PGE2 and thromboxane B2 (TXB2) measurements.

RESULTS

The bupivacaine/rofecoxib group reported significantly less pain, as assessed by a visual analog scale, compared with the other three treatment groups over the first 4 h. However, the bupivacaine/placebo group reported significantly more pain at 24 h and PGE2 levels during the first 4 h were significantly higher than the other three treatment groups. Moreover, bupivacaine significantly increased COX-2 gene expression at 48 h as compared with the lidocaine/placebo group. Thromboxane levels were not significantly affected by any of the treatments, indicating that the effects seen were attributable to inhibition of COX-2, but not COX-1.

CONCLUSIONS

These results suggest that bupivacaine stimulates COX-2 gene expression after tissue injury, which is associated with higher PGE2 production and pain after the local anesthetic effect dissipates.

Effect of neurolytic nerve block on systemic carrageenan-induced inflammatory response in mice

BACKGROUND

Local tissue inflammation caused by injury or inflammatory processes may be reduced by section or local anaesthetic block of the nerve innervating the inflamed area.

METHODS

Using a neurolytic nerve block, we assessed the systemic inflammatory response elicited by a local injection of carrageenan in mice. Sixty mice received a unilateral sciatic nerve block with 70% ethanol followed 5 days later by an injection of carrageenan on the ipsilateral or contralateral hind paw. Whole blood was sampled 15 h after carrageenan injection.

RESULTS

Fifty-six animals had a complete nerve block. Tumour necrosis factor-alpha (TNF-alpha), interleukin 1beta (IL-1beta) and interleukin 10 (IL-10) concentrations were measured in the plasma of 20 mice (10 in the ispilateral group and 10 in the contralateral group). In the remaining 36 mice (18 in each group), blood was cultured for 24 h in the presence of lipopolysaccharide or Staphylococcus aureus extract. TNF-alpha and IL-1beta production in the supernatant were, on average, 30% lower in the ispilateral group than in the contralateral group.

CONCLUSION

A prolonged nerve block decreases the systemic consequences of the local inflammatory reaction elicited by carrageenan injection.