Toxicity of corticosteroids and catecholamines for mice neuronal cell cultures: Role of preservatives

The effect of perineural dexamethasone on nerve injury and recovery of nerve function after surgery: A randomized controlled trial

Background

While numerous studies have examined the influence of perineural dexamethasone on nerve block duration, its potential impact on postoperative nerve injury has not been adequately addressed.

Objective

This study aims to elucidate the effect of perineural dexamethasone on nerve injury and nerve function recovery after surgery.

Design

A prospective randomized double-blinded trial.

Setting

The First Affiliated Hospital of Chengdu Medical College, Chengdu, China. The study was conducted between 14 June and 30 December 2022.

Participants

Patients aged 18 - 80 years, ASA I - II, scheduled for elective orthopedic or burn and plastic surgery.

Interventions

Patients were randomized to receive either perineural dexamethasone (D group) or no dexamethasone (ND group).

Main outcome measures

Primary outcomes were the incidence and recovery of nerve injury. Secondary outcomes included postoperative pain scores, analgesic consumption, and adverse events.

Results

Initial postoperative nerve injury rates were similar between groups (D: 30.4 %, ND: 33.3 %, P > 0.05). At 12 weeks post-discharge, significantly more patients in the ND group recovered from nerve deficits (78.8 % vs 60.3 %; OR = 2.45, 95 % CI = 1.05 - 5.72, P < 0.05). No significant differences were observed in postoperative hyperglycemia or surgical site infection rates.

Conclusion

Perineural dexamethasone may impede nerve function recovery, suggesting caution in its use, particularly for patients with pre-existing nerve damage or diabetes. Further research is needed to elucidate the long-term effects of dexamethasone on nerve tissue recovery.

Trial registration

chictr.org.cn, ChiCTR2200059424.

Effectiveness of Adding Dexamethasone to Lidocaine in Upper Limbs Nerve Blocks: A Systematic Review

PURPOSE

The use of perineural dexamethasone as an adjuvant drug to peripheral nerve block for postoperative pain is controversial. This systematic review aimed to determine the effectiveness of adding dexamethasone to lidocaine in upper limb nerve blocks.

DESIGN

Systematic review.

METHODS

This review used a comprehensive search strategy to retrieve relevant published randomized trial articles that fulfilled the inclusion and exclusion criteria, without time limits, (until December 2023) that assessed the effects of a combination of dexamethasone to lidocaine in upper limb nerve blocks. The databases used for the electronic literature search included PubMed, Embase, and Clinical Trials.gov, dbGaP, Cochrane library, and Google Scholar. There was no language, gender, or age limitation. This systematic review is reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis statement.

FINDINGS

Of 3,926 articles identified by the initial search, 8 studies that met our inclusion criteria. All articles were original research studies. All eight articles were clinical trials. The sample size in the selected studies ranged from 30 to 90 people. Studies demonstrated that combining dexamethasone with lidocaine significantly improved the quality of peripheral nerve blocks, increased the analgesia period, and decreased analgesic consumption.

CONCLUSIONS

This review supported that the combination of dexamethasone (dose of 4 to 10 mg) and lidocaine (concentration of 1.5% to 2%) for upper limb block was more effective and beneficial without any side effects. However, further clinical trials in this regard with more data, various regions, and larger sample sizes to support our hypothesis are recommended.

Synergistic activity of dobutamine combined with azoles and its mechanism of action against strains of Candida glabrata

Aims: To evaluate the antifungal effect of dobutamine against Candida glabrata as well as its synergism with azoles and its action on biofilm. Methods: The M27-A3 protocol and flow cytometry were used for elucidation of the possible mechanism of action. Results: The tested isolates presented MICs ranging from 2 to 32 μg/ml for dobutamine, with fungistatic effect. A total of 82% of the strains showed synergism with fluconazole, with 90% showing synergism with itraconazole. The effect on biofilm formation was nonsignificant. Cytometry tests showed that dobutamine induced mitochondrial depolarization. Conclusion: Dobutamine has an antifungal effect on strains of C. glabrata and synergistic activity with azoles. This effect is probably mediated by increased oxidative damage to the membrane.

Efficacy of perineural dexamethasone in prolonging duration of analgesia with peripheral nerve blocks compared to intravenous dexamethasone: A systematic review and meta-analysis

Background

Perineural dexamethasone has been regarded as a promising adjunct for prolonging the duration of nerve blocks. However, it is uncertain whether its effects are due to local effects on the nerves or from systemic absorption. This systematic review aimed to compare the duration of postoperative analgesia associated with perineural versus intravenous dexamethasone as an adjunct to peripheral nerve blocks.

Methods

A total of 2,216 relevant academic articles were identified after a comprehensive search of PubMed, Embase, Scopus, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from 1967 until 2020. All randomized controlled trials that compared perineural and intravenous dexamethasone as adjuncts to peripheral nerve limb blocks were included.

Results

Fifteen randomized controlled trials (1,467 cases; 738 perineural dexamethasone, 729 intravenous dexamethasone) were eligible. The primary outcome (duration of analgesia) was significantly longer in the perineural than in the intravenous dexamethasone group (mean difference [MD]: 2.72 h, 95% CI [1.42, 4.01], P < 0.001). Perineural dexamethasone was also found to prolong the sensory block (MD: 3.45 h, 95% CI [1.36, 5.54], P = 0.001) and lower 24 h postoperative pain scores (MD: −0.74 h, 95% CI [−1.40, −0.07], P = 0.03).

Conclusions

This review confirms the greater efficacy of perineural compared to intravenous dexamethasone in prolonging the analgesic duration of peripheral nerve blocks. However, the extent of prolongation was small and may not represent a clinically meaningful difference.

Review of adjuvants to local anesthetics in peripheral nerve blocks: Current and future trends

In recent anesthetic practice, peripheral nerve blocks (PNBs) are used extensively for surgical anesthesia and nonsurgical analgesia. PNBs offer many benefits over other anesthetic techniques in a certain population of patients, and in some specific clinical setting, that may contribute to faster and safer pain relief, increased patient satisfaction, reduced hospital stay, and decreased overall healthcare cost. The technique involves the injection of the anesthetic in the vicinity of a specific nerve or bundle of nerves to block the sensation of pain transmitting to a specific portion of the body. However, the length of analgesia when a single anesthetic is used for PNB may not last long. Therefore, the practice of adding an additional agent called adjuvant has been evolved to prolong the analgesic effect. There are many such adjuvants available that are clinically being used for this purpose imparting great efficacy and safety to the anesthetic process. The adjuvants molecules are generally classified as opioids, alpha-2 agonist, steroids, etc. Most of them are safe to use and show little or no adverse event related to neurotoxicity and tissue damage. Although there is extensive use of such adjuvants in the clinical field, none of the molecules is approved by the FDA and is used as an off-label drug. The risk to benefit ratio must be assessed while using such an agent. This review will try to delineate the basic need of adjuvant in peripheral nerve block and will discuss the advantages and limitations of using different adjuvants and will discuss the future prospect of such application.

Engineering advanced neural tissue constructs to mitigate acute cerebral inflammation after brain transplantation in rats

Stroke, traumatic brain injuries, and other similar conditions often lead to significant loss of functional brain tissue and associated disruption of neuronal signaling. A common strategy for replacing lost neurons is the injection of dissociated neural stem cells or differentiated neurons. However, this method is unlikely to be suitable for replacing large brain cavities, and the resulting distribution of neurons may lack the necessary architecture to support appropriate brain function. Engineered neural tissues may be a viable alternative. Cell death is a prominent concern in neuronal grafting studies, a problem that could be magnified with the transplantation of engineered neural tissues. Here, we examined the effect of one contributor to cell death, acute cerebral inflammation, on neuronal survival after the transplantation of bioengineered constructs based on silk scaffolds. We found evidence of a high degree of inflammation and poor neuronal survival after introducing engineered constructs into the motor cortex of rats. Integrating a corticosteroid (methylprednisolone) into the constructs resulted in significantly improved neuron survival during the acute phase of inflammation. The improved construct survival was associated with decreased markers of inflammation and an anti-inflammatory state of the immune system due to the steroid treatment.

Efficacy of Curcumin in the Modulation of Anxiety Provoked by Sulfite, a Food Preservative, in Rats

Sulfites are used as food preservatives and excessive sulfite might disturb the body systems including the brain. Curcumin shows protective effects on the nervous system toxicity. The present study aimed to evaluate the protective role of curcumin in sulfite-induced anxiety in rats. Male rats were divided into five groups. The rats in groups I to V received distilled water (vehicle of sulfite, 1 mL/d), olive oil (vehicle of curcumin, 1 mL/d), curcumin (100 mg/kg/d), sulfite (25 mg/kg/d), and sulfite+curcumin, respectively, by daily gastric gavage for 8 weeks. At the end of 8 weeks the rats were tested in the elevated plus-maze for anxiety. The results showed that concomitant treatment of curcumin during sulfite consumption prevented the reduction of the time spent in the open arm and entrance to the open arm (the indexes of anxiety). Besides, an increase was found in motor activity of the rats in the sulfite+curcumin group compared to the sulfite-treated animals. Exposure of sulfite in rats can induce anxiety, and curcumin can act as an anti-anxiety agent.

[Glucocorticoids as an adjunct in peripheral regional anesthesia. Move to the "Holy Grail of perineural analgesia"?!]

BACKGROUND

The role of dexamethasone as an adjunct in peripheral nerve blockades is still unclear.

OBJECTIVES

This article reviews the actual knowledge and scientific evidence for dexamethasone as an adjunct in peripheral regional anesthesia. Moreover, it discusses the benefits of the systemic versus the perineural mode of application.

RESULTS

Dexamethasone prolongs sensible as well as motor blockades in peripheral nerve blocks when applied intravenously or perineurally. Regarding potentially local neurotoxicity, published patient data are not sufficient for final conclusions.

CONCLUSIONS

After reviewing the actual literature, the authors prefer a systemic application mode (intravenously) over a perineural route of administration of dexamethasone as an adjunct for peripheral nerve blocks. This is due to the better understanding of potential side effects of the drug when applied intravenously. Dexamethasone might be a useful drug adjunct to prolong peripheral single shot nerve blocks.

Local Anesthetic Peripheral Nerve Block Adjuvants for Prolongation of Analgesia: A Systematic Qualitative Review

Background

The use of peripheral nerve blocks for anesthesia and postoperative analgesia has increased significantly in recent years. Adjuvants are frequently added to local anesthetics to prolong analgesia following peripheral nerve blockade. Numerous randomized controlled trials and meta-analyses have examined the pros and cons of the use of various individual adjuvants.

Objectives

To systematically review adjuvant-related randomized controlled trials and meta-analyses and provide clinical recommendations for the use of adjuvants in peripheral nerve blocks.

Methods

Randomized controlled trials and meta-analyses that were published between 1990 and 2014 were included in the initial bibliographic search, which was conducted using Medline/PubMed, Cochrane Central Register of Controlled Trials, and EMBASE. Only studies that were published in English and listed block analgesic duration as an outcome were included. Trials that had already been published in the identified meta-analyses and included adjuvants not in widespread use and published without an Investigational New Drug application or equivalent status were excluded.

Results

Sixty one novel clinical trials and meta-analyses were identified and included in this review. The clinical trials reported analgesic duration data for the following adjuvants: buprenorphine (6), morphine (6), fentanyl (10), epinephrine (3), clonidine (7), dexmedetomidine (7), dexamethasone (7), tramadol (8), and magnesium (4). Studies of perineural buprenorphine, clonidine, dexamethasone, dexmedetomidine, and magnesium most consistently demonstrated prolongation of peripheral nerve blocks.

Conclusions

Buprenorphine, clonidine, dexamethasone, magnesium, and dexmedetomidine are promising agents for use in prolongation of local anesthetic peripheral nerve blocks, and further studies of safety and efficacy are merited. However, caution is recommended with use of any perineural adjuvant, as none have Food and Drug Administration approval, and concerns for side effects and potential toxicity persist.

Risk assessment of neonatal excipient exposure: lessons from food safety and other areas

Newborn babies can require significant amounts of medication containing excipients intended to improve the drug formulation. Most medicines given to neonates have been developed for adults or older children and contain excipients thought to be safe in these age groups. Many excipients have been used widely in neonates without obvious adverse effects. Some excipients may be toxic in high amounts in which case they need careful risk assessment. Alternatively, it is conceivable that ill-founded fears about excipients mean that potentially useful medicines are not made available to newborn babies. Choices about excipient exposure can occur at several stages throughout the lifecycle of a medicine, from product development through to clinical use. Making these choices requires a scalable approach to analysing the overall risk. In this contribution we examine these issues.

Cardiac peroxisome proliferator-activated receptor δ (PPARδ) as a new target for increased contractility without altering heart rate

Background and Aims

Agents having a positive inotropic effect on the heart are widely used for the treatment of heart failure. However, these agents have the side effect of altering heart rate. It has been established that peroxisome proliferator-activated receptor δ (PPARδ) is mediated in cardiac contraction, however the effect on heart rate is unknown. Thus, we used an agonist of PPARδ, GW0742, to investigate this issue in the present study.

Methods and Results

We used isolated hearts in Langendorff apparatus and hemodynamic analysis in catheterized rats to measure the actions of GW0742 extra-vivo and in vivo. In diabetic rats with heart failure, GW0742 at a dose sufficient to activate PPARδ reversed cardiac contraction without changes in heart rate. In normal rats, PPARδ enhanced cardiac contractility and hemodynamic dP/dt_max significantly more than dobutamine. Both actions were diminished by GSK0660 at a dose enough to block PPARδ. However, GW0742 at the same dose failed to modify heart rate, although it did produce a mild increase in blood pressure. Detection of intracellular calcium level and Western blotting analysis showed that the intracellular calcium concentration and troponin I phosphorylation were both enhanced by GW0742.

Conclusion

Activation of PPARδ by GW0742 increases cardiac contractility but not heart rate. Thus, PPARδ may be a suitable target for the development of inotropic agents to treat heart failure without changing heart rate.

Curcumin, the main part of turmeric, prevents learning and memory changes induced by sodium metabisulfite, a preservative agent, in rats

Sodium metabisulfite is used as a disinfectant, antioxidant, and preservative agent in the food, beverage, and drug industries. Neurons are highly sensitive to sulfite toxicity. Curcumin is the main part of turmeric and has neuroprotective effects on a variety of nervous system damages. The present study aimed to investigate the possible protective role of curcumin in learning and memory after exposure to sulfite in rats. The rats were divided into five groups receiving distilled water (solvent of the sulfite), olive oil (solvent of the curcumin), sodium metabisulfite (25 mg/kg/day), curcumin (100 mg/kg/day), and sulfite + curcumin. All the animals received daily gavages for 8 weeks. At the end of the 8(th) week, learning and memory were assessed in a partially-baited eight arm radial maze. The animals treated with sulfite showed fewer correct choices and more reference and working memory errors during the learning phase, at the end of the learning phase, and during the retention testing (p<0.001). The study results demonstrated that sulfite-exposure was associated with impaired learning and memory in rats. Adding curcumin to the rat nutrition plays a protective role in learning and memory after exposure to sulfite.

Epidural steroid injections are associated with less improvement in patients with lumbar spinal stenosis: a subgroup analysis of the Spine Patient Outcomes Research Trial

STUDY DESIGN

Subgroup analysis of prospective, randomized database from the Spine Patient Outcomes Research Trial (SPORT).

OBJECTIVE

The hypothesis of this study was that patients who received ESI during initial treatment as part of SPORT (The Spine Patient Outcomes Research Trial) would have improved clinical outcome and a lower rate of crossover to surgery than patients who did not receive ESI.

SUMMARY OF BACKGROUND DATA

The use of epidural steroid injection (ESI) in patients with lumbar spinal stenosis is common, although there is little evidence in the literature to demonstrate its long-term benefit in the treatment of lumbar stenosis.

METHODS

Patients with lumbar spinal stenosis who received ESI within the first 3 months of enrollment in SPORT (ESI) were compared with patients who did not receive epidural injections during the first 3 months of the study (no-ESI).

RESULTS

There were 69 ESI patients and 207 no-ESI patients. There were no significant differences in demographic factors, baseline clinical outcome scores, or operative details between the groups, although there was a significant increase in baseline preference for nonsurgical treatment among ESI patients (ESI 62% vs. no-ESI 33%, P < 0.001). There was an average 26-minute increase in operative time and an increased length of stay by 0.9 days among the ESI patients who ultimately underwent surgical treatment. Averaged over 4 years, there was significantly less improvement in 36-Item Short Form Health Survey (SF-36) Physical Function among surgically treated ESI patients (ESI 14.8 vs. no-ESI 22.5, P = 0.025). In addition, there was significantly less improvement among the nonsurgically treated patients in SF-36 Body Pain (ESI 7.3 vs. no-ESI 16.7, P = 0.007) and SF-36 Physical Function (ESI 5.5 vs. no-ESI 15.2, P = 0.009). Of the patients assigned to the surgical treatment group, there was a significantly increased crossover to nonsurgical treatment among patients who received an ESI (ESI 33% vs. no-ESI 11%, P = 0.012). Of the patients assigned to the nonoperative treatment group, there was a significantly increased crossover to surgical treatment in the ESI patients (ESI 58% vs. no-ESI 32%, P = 0.003).

CONCLUSION

Despite equivalent baseline status, ESIs were associated with significantly less improvement at 4 years among all patients with spinal stenosis in SPORT. Furthermore, ESIs were associated with longer duration of surgery and longer hospital stay. There was no improvement in outcome with ESI whether patients were treated surgically or nonsurgically.

The vasodilator mechanisms of sodium metabisulfite on precontracted isolated aortic rings in rats: signal transduction pathways and ion channels

Sodium metabisulfite (SMB) is most commonly used as a food additives, however few study was performed on the vasodilator effect of SMB. In the present paper, the vasodilator effects of SMB and roles of Ca(2+) and K(+) channels as well as the cGMP pathway on isolated rat aortic rings were studied. The results show that: (1) SMB could relax isolated aortic rings precontracted by norepinephrine in a concentration-dependent manner. The maximal endothelium-dependent vasorelaxation was approximately 20% whereas that not depending on the presence of the endothelium was more than 90%. (2) The vasorelaxant effects induced by 50 or 200 μM SMB were partially inhibited by iberiotoxin, NS-2028 or l-NNA. The vasorelaxation of 1000 μM SMB was partially inhibited by nifedipine or glibenclamide. The SMB induced vasorelaxation was partially inhibited by tetraethylammonium. These results led to the conclusions that the vasorelaxation of SMB at low concentrations (<400 μM) was endothelium-dependent and mediated by the cGMP pathway and BK(Ca) channel, but at high concentrations (>500 μM) was endothelium-independent and mediated by K(ATP) channel and L-type Ca(2+) channel. The maximal allowable concentration from China and the acceptable daily intake level from WHO of SMB as a food additive should be revised.

Hippocampal neuron number loss in rats exposed to ingested sulfite

Sulfite, which is continuously formed in the body during metabolism of sulfur-containing amino acids, is commonly used in preservatives. It has been shown that there are toxic effects of sulfite on many cellular components. The aim of this study was to investigate the possible toxic effects of sulfite on pyramidal neurons by counting cell numbers in CA1 and CA2-CA3 subdivisions of the rat hippocampus. For this purpose, male albino rats were divided into a control group and a sulfite group (25 mg/kg). Sulfite was administered to the animals via drinking water for 8 weeks. At the end of the experimental period, brains were removed and neurons were estimated in total and in a known fraction of CA1 and CA2-CA3 subdivisions of the left hippocampus by using the optical fractionator method—a stereological method. Results showed that sulfite treatment caused a significant decrease in the total number of pyramidal neurons in three subdivisions of the hippocampus (CA1 and CA2-CA3) in the sulfite group compared with the control group (p < 0.05, Mann Whitney U test). It was concluded that exogenous administration of sulfite causes loss of pyramidal neurons in CA1 and CA2-CA3 subdivisions of the rat hippocampus.

Chondrotoxicity of low pH, epinephrine, and preservatives found in local anesthetics containing epinephrine

BACKGROUND

Recent clinical and basic science investigations have revealed the chondrotoxicity of local anesthetics, especially those containing epinephrine, administered via an intra-articular pain pump. However, the exact mechanism of toxicity is unknown. This study evaluates the chondrotoxicity of low pH, epinephrine, and preservatives found in commonly used local anesthetics.

HYPOTHESIS

The chondrotoxicity of local anesthetics containing epinephrine is due to low pH, epinephrine, or the preservative sodium metabisulfite.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human chondrocytes were harvested and cultured in a custom bioreactor designed to simulate metabolism of medication. Pain pumps were used to infuse one of the following medications into the culture system: control media; media titrated to pH 4.5, 5.0, 5.5, 6.0, 6.5; media with 1:100000 or 1:200000 epinephrine only; media with 0.5 mg/mL of sodium metabisulfite preservative; media with 0.5 mg/mL of methylparaben preservative, 0.25% bupivacaine, 0.25% bupivacaine with epinephrine, 1% lidocaine, and 1% lidocaine with epinephrine. Cultures were perfused for 24 hours and then were stained with live/dead cell viability assay. The chondrocytes were then examined by fluorescence microscopy and counted, and the percentage of cell death was calculated.

RESULTS

Cultures containing media titrated to pH 4.5 and 5.0 and local anesthetics containing epinephrine (pH 4.0-5.5) had high cell death rates compared with controls at all time points (P < .001), while cultures containing 1:100000 and 1:200000 epinephrine alone had no increased death rate. Also, 0.5 mg/mL sodium metabisulfite preservative had a significant effect on cell death (P < .034); however, the preservative methylparaben had no effect (P > .05). The percentage of cell death was not significant for 1% lidocaine (12.5%; P > .943) and 0.25% bupivacaine (16.5%; P > .609).

CONCLUSION

The marked chondrotoxicity of local anesthetics containing epinephrine appears to be a combined effect of low pH, as these medications are titrated to pH 4.0 to 5.5 for product stability, and the preservative sodium metabisulfite. Extreme caution should be exercised when using intra-articular pain pumps with local anesthetics containing epinephrine.

CLINICAL RELEVANCE

Understanding the causes of chondrotoxicity using local anesthetics containing epinephrine is critical to decrease complications associated with this class of medications.

Specific p38 inhibition in stimulated endothelial cells: a possible new anti-inflammatory strategy after hypothermia and rewarming

To protect immature organ systems during corrective cardiac surgery, patients are cooled to a minimal temperature of 17 degrees C during cardiopulmonary bypass (CPB). However hypothermic CPB triggers the whole body inflammatory response and results in unwanted prolonged inflammation. The present study was designed to clarify the hypothermia and rewarming induced mechanisms and examine interventional pharmacological strategies that could prevent prolonged inflammation. Stimulated primary human umbilical vein endothelial cells (HUVECs) were exposed to a dynamic temperature protocol analogous to clinical settings. Furthermore endothelial cells were pretreated with methylprednisolone and/or tacrolimus as well as with MAPK inhibitors (SB203580, U0126 and SP600125). Cell viability, expression of IL-6 and ERK 1/2, p38 and SAPK/JNK were investigated. Stimulated endothelial cells secreted significantly higher IL-6 protein 2h after rewarming in comparison to normothermic control cells. Moreover, dynamic temperature changes lead to increased MAPK phosphorylation. Only the combined pre-treatment with MP and TAC served to inhibit the IL-6 secretion. As intracellular signalling pathway we could demonstrate that SB203580 as specific p38 inhibitor most effectively down regulated the unwanted IL-6 release after cooling and rewarming. Therefore inhibition of p38 or components of the p38 pathway could be a promising and selective antiinflammatory therapeutic target after hypothermic CPB.