Effect of lidocaine and ropivacaine on primary (SW480) and metastatic (SW620) colon cancer cell lines.

Regional anesthesia may prolong survival following surgery for different types of cancers. The mechanisms behind this are unclear but direct effects on cancer cells by local anesthetics (LA) have been suggested. The aim of this study was to investigate if lidocaine or ropivacaine have a dose-dependent effect on the cell viability and proliferation of a primary and a secondary colon carcinoma cell line in vitro. The colon cancer cell lines SW480 derived from primary tumor and SW620 from a metastatic site in the same patient were exposed to increasing concentrations of lidocaine and ropivacaine (5-1,000 µM). Cell viability was measured using CellTiter-Blue® and cell proliferation by PKH67 after exposure for up to 72 h. Cell viability was significantly reduced by ropivacaine at the highest concentration (1,000 µM) after 48 and 72 h in the cell line SW480 and at 72 h in SW620. Exposure to lidocaine did not show any significant reduction in cell viability. Notably, low concentrations of both lidocaine and ropivacaine significantly increased cell viability after 48 and 72 h in SW620. Cell proliferation was significantly reduced by 1,000 µM lidocaine in SW480 and by 1,000 µM ropivacaine in SW620. In summary, both lidocaine and ropivacaine showed an anti-proliferative effect in the colon cancer cell lines at high concentrations and after prolonged exposure to LA in vitro. Our findings also indicate that lower concentrations promote cell viability in the metastatic cell line.

How Anesthetic, Analgesic and Other Non-Surgical Techniques During Cancer Surgery Might Affect Postoperative Oncologic Outcomes: A Summary of Current State of Evidence.

The question of whether anesthetic, analgesic or other perioperative intervention during cancer resection surgery might influence long-term oncologic outcomes has generated much attention over the past 13 years. A wealth of experimental and observational clinical data have been published, but the results of prospective, randomized clinical trials are awaited. The European Union supports a pan-European network of researchers, clinicians and industry partners engaged in this question (COST Action 15204: Euro-Periscope). In this narrative review, members of the Euro-Periscope network briefly summarize the current state of evidence pertaining to the potential effects of the most commonly deployed anesthetic and analgesic techniques and other non-surgical interventions during cancer resection surgery on tumor recurrence or metastasis.

Effect of hyperoxia on neurogenic plasma protein extravasation in the rat dura mater.

OBJECTIVE: We aimed to study the effect of normobaric hyperoxia on neurogenic inflammation of the rat dura mater. BACKGROUND: Inhalation of 100% oxygen is a first-line therapy for the treatment of acute cluster headache (CH). However, the mechanisms underlying the antinociceptive effect of oxygen are poorly understood. Sumatriptan, which is also effective in aborting CH attacks, is known to inhibit neurogenic inflammation of the dura mater. We hypothesized that hyperoxia reduces dural plasma protein extravasation in the model of electrically stimulating the rat trigeminal ganglion. METHODS: Unilateral stimulation of the trigeminal ganglion was performed in anesthetized male Sprague-Dawley rats. We assessed plasma protein extravasation (PPE) in the ipsilateral dura mater under normoxic (group 1) and hyperoxic conditions (group 2: pO(2) 200 mmHg; group 3: pO(2) 300 mmHg; group 4: pO(2) 400 mmHg). The study results were compared to the effect of sumatriptan (300 microg/kg) on dural PPE. RESULTS: Under normoxic conditions, the calculated extravasation ratio was 1.72 +/- 0.2. Hyperoxic treatment (groups 2, 3, 4) significantly attenuated dural PPE. At oxygen levels of 400 mmHg, the PPE ratio was 1.14 +/- 0.2 (P < .01). After IV application of sumatriptan (300 microg/kg), PPE was nearly abolished (PPE ratio: 1.06 +/-0.17). CONCLUSION: Our findings demonstrate that hyperoxia is able to inhibit dural PPE. Hyperoxia may play an anti-inflammatory role in neurogenic inflammation, but further studies are needed to clarify whether this effect is either caused by prejunctional mechanisms or by modulation of the vascular permeability at postcapillary venules.

A fluorescence-based method to assess plasma protein extravasation in rat dura mater using confocal laser scanning microscopy.

We describe a nonradioactive, fluorescence-based method to assess plasma protein extravasation (PPE) in rat dura mater using confocal laser scanning microscopy (CLSM). Unilateral PPE can be induced by electrical stimulation of the ipsilateral trigeminal ganglion (TG) and is widely used as an experimental migraine model. The gold standard to determine PPE in the meninges is based on the detection of radiolabeled albumin ([125]I-BSA). The aim of this study was to develop a nonradioactive, histological method to quantify PPE in the meninges. The fluorescent dye Evans Blue (50 mg/kg) was injected intravenously to the rat 7 min prior to TG stimulation. PPE in dura mater was detected by a CLSM. The amount of extravasated Evans Blue in the dura mater was measured at six to eight regions of interest (ROIs) in the vicinity of large meningeal vessels. The ratio of the average fluorescence intensity within dura mater of the "stimulus side", compared to the contralateral "control side", was calculated for each animal. By using this method, The PPE ratio was 1.67+/-0.12 (n=5). Intravenous injection of three different dosages of the 5HT(1B/1D)-receptor agonist sumatriptan (25, 50, and 100 microg/kg) 15 min prior to stimulation attenuated PPE by 42+/-12%, 49+/-9%, and 86+/-15%, respectively (p<0.01). The approximated ED(50) value was 48 microg/kg. Our results are in accordance with previous reports in the literature using the radioactive approach. We conclude that CLSM is a safe, sensitive, and reliable method to assess PPE in rat meninges in an experimental migaine model.