Opposing effects of dexamethasone, agrin and sugammadex on functional innervation and constitutive secretion of IL-6 in in vitro innervated primary human muscle cells

Chronic exposure to dexamethasone may not affect sugammadex reversal of rocuronium-induced neuromuscular blockade: an in vivo study on rats

BACKGROUND

Chronic glucocorticoid exposure is associated with resistance to nondepolarizing neuromuscular blocking agents. Therefore, we hypothesized that sugammadex-induced recovery would occur more rapidly in subjects exposed to chronic dexamethasone compared to those who were not exposed. This study evaluated the sugammadex-induced recovery profile after neuromuscular blockade (NMB) in rats exposed to chronic dexamethasone.

METHODS

Sprague-Dawley rats were allocated to three groups (dexamethasone, control, and pair-fed group) for the in vivo study. The mice received daily intraperitoneal dexamethasone injections (500 μg/kg) or 0.9% saline for 15 days. To achieve complete NMB, 3.5 mg/kg rocuronium was administered on the sixteenth day. The recovery time to a train-of-four ratio ≥ 0.9 was measured to evaluate the complete recovery following the sugammadex injection.

RESULTS

Among the groups, no significant differences were observed in the recovery time to a train-of-four ratio ≥ 0.9 following sugammadex administration (P = 0.531). The time to the second twitch of the train-of-four recovery following rocuronium administration indicated that the duration of NMB was significantly shorter in Group D than that in Groups C and P (P = 0.001).

CONCLUSIONS

Chronic exposure to dexamethasone did not shorten the recovery time of sugammadex-induced NMB reversal. However, the findings of this study indicated that no adjustments to sugammadex dosage or route of administration is required, even in patients undergoing long-term steroid treatment.

Innervation and electrical pulse stimulation — in vitro effects on human skeletal muscle cells

Contraction-induced adaptations in skeletal muscles are well characterized in vivo, but the underlying cellular mechanisms are still not completely understood. Cultured human myotubes represent an essential model system for human skeletal muscle that can be modulated ex vivo, but they are quiescent and do not contract unless being stimulated. Stimulation can be achieved by innervation of human myotubes in vitro by co-culturing with embryonic rat spinal cord, or by replacing motor neuron activation by electrical pulse stimulation (EPS). Effects of these two in vitro approaches, innervation and EPS, were characterized with respects to the expression of myosin heavy chains (MyHCs) and metabolism of glucose and oleic acid in cultured human myotubes. Adherent human myotubes were either innervated with rat spinal cord segments or exposed to EPS. The expression pattern of MyHCs was assessed by quantitative polymerase chain reaction, immunoblotting, and immunofluorescence, while the metabolism of glucose and oleic acid were studied using radiolabelled substrates. Innervation and EPS promoted differentiation towards different fiber types in human myotubes. Expression of the slow MyHC-1 isoform was reduced in innervated myotubes, whereas it remained unaltered in EPS-treated cells. Expression of both fast isoforms (MyHC-2A and MyHC-2X) tended to decrease in EPS-treated cells. Both approaches induced a more oxidative phenotype, reflected in increased CO2 production from both glucose and oleic acid.

Novelty: Innervation and EPS favour differentiation into different fiber types in human myotubes. Both innervation and EPS promote a metabolically more oxidative phenotype in human myotubes.

Effect of differentiation, de novo innervation, and electrical pulse stimulation on mRNA and protein expression of Na+,K+-ATPase, FXYD1, and FXYD5 in cultured human skeletal muscle cells

Denervation reduces the abundance of Na⁺,K⁺-ATPase (NKA) in skeletal muscle, while reinnervation increases it. Primary human skeletal muscle cells, the most widely used model to study human skeletal muscle in vitro, are usually cultured as myoblasts or myotubes without neurons and typically do not contract spontaneously, which might affect their ability to express and regulate NKA. We determined how differentiation, de novo innervation, and electrical pulse stimulation affect expression of NKA (α and β) subunits and NKA regulators FXYD1 (phospholemman) and FXYD5 (dysadherin). Differentiation of myoblasts into myotubes under low serum conditions increased expression of myogenic markers CD56 (NCAM1), desmin, myosin heavy chains, dihydropyridine receptor subunit α_1S, and SERCA2 as well as NKAα2 and FXYD1, while it decreased expression of FXYD5 mRNA. Myotubes, which were innervated de novo by motor neurons in co-culture with the embryonic rat spinal cord explants, started to contract spontaneously within 7–10 days. A short-term co-culture (10–11 days) promoted mRNA expression of myokines, such as IL-6, IL-7, IL-8, and IL-15, but did not affect mRNA expression of NKA, FXYDs, or myokines, such as musclin, cathepsin B, meteorin-like protein, or SPARC. A long-term co-culture (21 days) increased the protein abundance of NKAα1, NKAα2, FXYD1, and phospho-FXYD1^Ser68 without attendant changes in mRNA levels. Suppression of neuromuscular transmission with α-bungarotoxin or tubocurarine for 24 h did not alter NKA or FXYD mRNA expression. Electrical pulse stimulation (48 h) of non-innervated myotubes promoted mRNA expression of NKAβ2, NKAβ3, FXYD1, and FXYD5. In conclusion, low serum concentration promotes NKAα2 and FXYD1 expression, while de novo innervation is not essential for upregulation of NKAα2 and FXYD1 mRNA in cultured myotubes. Finally, although innervation and EPS both stimulate contractions of myotubes, they exert distinct effects on the expression of NKA and FXYDs.

The effect of dexamethasone on sugammadex reversal of rocuronium-induced neuromuscular blockade in surgical patients undergoing general anesthesia: A systematic review and meta-analysis

BACKGROUND

There have been conflicting results regarding clinical dexamethasone-sugammadex interactions in adults and pediatric patients under general anesthesia.

METHODS

This study used a systematic review with meta-analysis of randomized controlled trials and non-randomized studies based on the Cochrane Review Methods. A comprehensive literature search was conducted to identify clinical trials that investigated the effect of dexamethasone on sugammadex reversal of rocuronium-induced neuromuscular blockade in surgical patients undergoing general anesthesia.

RESULTS

Among the 314 patients in the 6 studies, 147 received intravenous dexamethasone (dexamethasone group), and 167 received intravenous saline or other antiemetics (control group). The primary outcome, the time to recovery after sugammadex administration (the time to recovery of the train-of-four ratio to 0.9 after sugammadex administration; s) was comparable between the 2 groups, the weighted mean difference (95% confidence interval [CI]) being -2.93 (-36.19, 30.33) (I2 = 94%). The time to extubation after sugammadex administration (s) and incidence of postoperative nausea and vomiting was not different between the 2 groups, the weighted mean difference (95% CI) being 23.31 (-2.26, 48.88) (I2 = 86%) and the pooled risk ratio (95% CI) being 0.25 (0.03, 2.11), respectively. The time to recovery after sugammadex administration might be different according to the study design or study region.

CONCLUSION

This meta-analysis showed that use of dexamethasone in the perioperative period neither delayed nor facilitated the reversal of rocuronium-induced neuromuscular blockade with sugammadex in patients undergoing elective surgery with general anesthesia. However, given that the results showed high heterogeneity, further randomized controlled trials are needed to confirm these findings.

[Influence of methylprednisolone on the reversal time of sugammadex: a randomized clinical trial]

BACKGROUND AND OBJECTIVES

Sugammadex is a modified gamma-cyclodextrin that reverses the effects of aminosteroidal neuromuscular blocking agents. Likewise, some steroid molecules, such as toremifene, fusidic acid, and flucloxacillin, can also be encapsulated by sugammadex. Methylprednisolone, which is a synthetic steroid used commonly for airway oedema prophylaxis, can also be encapsulated by sugammadex. The objective of this study was to compare the recovery times of sugammadex for reversing rocuronium-induced moderate neuromuscular blockade in those who received intraoperative 1 mg.kg^-1 methylprednisolone or saline.

METHOD

This single-centered, randomized, controlled, prospective study included 162 adult patients undergoing elective ear-nose-throat procedures (aged from 18-65, an ASA physical status I-II, a BMI less than 30 kg.m^-2, and not taking steroid drug medication) with propofol, remifentanyl, rocuronium and sevoflurane. Neuromuscular monitoring was performed using calibrated acceleromyography. The Control Group (Group C) received 5 mL of saline, while the Methylprednisolone Group (Group M) received 1 mg.kg^-1 of methylprednisolone in 5mL of saline just after induction. After the completion of surgery, regarding the TOF count, two reappeared spontaneously and 2 mg.kg^-1 sugammadex was administered to all patients. Recovery of the TOF ratio to 0.9 was recorded for both groups, and the estimated recovery time to reach a TOF ratio (TOFr) of 0.9 was the primary outcome of the study.

RESULTS

Median time to TOFr = 0.9 was for 130.00 s (range of 29-330) for Group C and 181.00 s (100-420) for Group M (p < 0.001). The differences between the two groups were statistically significant.

CONCLUSION

When using 2 mg.kg^-1 of sugammadex to reverse rocuronium-induced neuromuscular blockade in patients who received 1 mg.kg^-1 of intraoperative methylprednisolone, demonstrated delayed recovery times.

Influence of methylprednisolone on the reversal time of sugammadex: a randomized clinical trial

Background and objectives

Sugammadex is a modified gamma-cyclodextrin that reverses the effects of aminosteroidal neuromuscular blocking agents. Likewise, some steroid molecules, such as toremifene, fusidic acid, and flucloxacillin, can also be encapsulated by sugammadex. Methylprednisolone, which is a synthetic steroid used commonly for airway edema prophylaxis, can also be encapsulated by sugammadex. The objective of this study was to compare the recovery times of sugammadex for reversing rocuronium-induced moderate neuromuscular blockade in those who received intraoperative 1 mg kg⁻¹ methylprednisolone or saline.

Method

This single-centered, randomized, controlled, prospective study included 162 adult patients undergoing elective ear-nose-throat procedures (aged from 18 to 65, an ASA physical status I-II, a BMI less than 30 kg m⁻², and not taking steroid drug medication) with propofol, remifentanyl, rocuronium and sevoflurane. Neuromuscular monitoring was performed using calibrated acceleromyography. The Control Group (Group C) received 5 mL of saline, while the Methylprednisolone Group (Group M) received 1 mg kg⁻¹ of methylprednisolone in 5 mL of saline just after induction. After the completion of surgery, regarding the TOF count, two reappeared spontaneously and 2 mg kg⁻¹ sugammadex was administered to all patients. Recovery of the TOF ratio to 0.9 was recorded for both groups, and the estimated recovery time to reach a TOF ratio (TOFr) of 0.9 was the primary outcome of the study.

Results

Median time to TOFr = 0.9 was for 130.00 s (range of 29–330) for Group C and 181.00 s (100–420) for Group M (p < 0.001). The differences between the two groups were statistically significant.

Conclusion

When using 2 mg kg⁻¹ of sugammadex to reverse rocuronium-induced neuromuscular blockade in patients who received 1 mg kg⁻¹ of intraoperative methylprednisolone, demonstrated delayed recovery times.

Effects of dexamethasone and hydrocortisone on rocuroniuminduced neuromuscular blockade and reversal by sugammadex in phrenic nerve-hemidiaphragm rat model

Background

The facilitator effects of steroids on neuromuscular transmission may cause resistance to neuromuscular blocking agents. Additionally, steroids may hinder sugammadex reversal of neuromuscular blockade, but these findings remain controversial. Therefore, we explored the effect of dexamethasone and hydrocortisone on rocuronium-induced neuromuscular blockade and their inhibitory effect on sugammadex.

Methods

We explored the effects of steroids, dexamethasone and hydrocortisone, in vitro using a phrenic nerve-hemidiaphragm rat model. In the first phase, an effective dose of rocuronium was calculated, and in the second phase, following sugammadex administration, the recovery of the train-of-four (TOF) ratio and T1 was evaluated for 30 minutes, and the recovery index was calculated in dexamethasone 0, 0.5, 5, and 50 μg/ml, or hydrocortisone 0, 1, 10, or 100 μg/ml.

Results

No significant effect of steroids on the effective dose of rocuronium was observed. The TOF ratios at 30 minutes after sugammadex administration were decreased significantly only at high experimental concentrations of steroids: dexamethasone 50 μg/ml and hydrocortisone 100 μg/ml (P < 0.001 and P = 0.042, respectively). There were no statistical significances in other concentrations. No differences were observed in T1. Recovery index was significantly different only in 100 μg/ml of hydrocortisone (P = 0.03).

Conclusions

Acute exposure to steroids did not resist the neuromuscular blockade caused by rocuronium. And inhibition of sugammadex reversal on rocuronium-induced neuromuscular blockade is unlikely at typical clinical doses of dexamethasone and also hydrocortisone. Conclusively, we can expect proper effects of rocuronium and sugammadex when dexamethasone or hydrocortisone is used during general anesthesia.

In Vitro Innervation as an Experimental Model to Study the Expression and Functions of Acetylcholinesterase and Agrin in Human Skeletal Muscle

Acetylcholinesterase (AChE) and agrin, a heparan-sulfate proteoglycan, reside in the basal lamina of the neuromuscular junction (NMJ) and play key roles in cholinergic transmission and synaptogenesis. Unlike most NMJ components, AChE and agrin are expressed in skeletal muscle and α-motor neurons. AChE and agrin are also expressed in various other types of cells, where they have important alternative functions that are not related to their classical roles in NMJ. In this review, we first focus on co-cultures of embryonic rat spinal cord explants with human skeletal muscle cells as an experimental model to study functional innervation in vitro. We describe how this heterologous rat-human model, which enables experimentation on highly developed contracting human myotubes, offers unique opportunities for AChE and agrin research. We then highlight innovative approaches that were used to address salient questions regarding expression and alternative functions of AChE and agrin in developing human skeletal muscle. Results obtained in co-cultures are compared with those obtained in other models in the context of general advances in the field of AChE and agrin neurobiology.

Dexamethasone does not diminish sugammadex reversal of neuromuscular block - clinical study in surgical patients undergoing general anesthesia

Background

Sugammadex reverses neuromuscular block (NMB) through binding aminosteroid neuromuscular blocking agents. Although sugammadex appears to be highly selective, it can interact with other drugs, like corticosteroids. A prospective single-blinded randomized clinical trial was designed to explore the significance of interactions between dexamethasone and sugammadex.

Methods

Sixty-five patients who were anesthetized for elective abdominal or urological surgery were included. NMB was assessed using train-of-four stimulation (TOF), with rocuronium used to maintain the desired NMB depth. NMB reversal at the end of anaesthesia was achieved using sugammadex. According to their received antiemetics, the patients were randomized to either the granisetron or dexamethasone group. Blood samples were taken before and after NMB reversal, for plasma dexamethasone and rocuronium determination. Primary endpoint was time from sugammadex administration to NMB reversal. Secondary endpoints included the ratios of the dexamethasone and rocuronium concentrations after NMB reversal versus before sugammadex administration.

Results

There were no differences for time to NMB reversal between the control (mean 121 ± 61 s) and the dexamethasone group (mean 125 ± 57 s; P = 0.760). Time to NMB reversal to a TOF ratio ≥0.9 was significantly longer in patients with lower TOF prior to sugammadex administration (Beta = −0.268; P = 0.038). The ratio between the rocuronium concentrations after NMB reversal versus before sugammadex administration was significantly affected by sugammadex dose (Beta = −0.375; P = 0.004), as was rocuronium dose per hour of operation (Beta = −0.366; p = 0.007), while it was not affected by NMB depth before administration of sugammadex (Beta = −0.089; p = 0.483) and dexamethasone (Beta = −0.186; p = 0.131). There was significant drop in plasma dexamethasone after sugammadex administration and NMB reversal (p < 0.001).

Conclusions

Administration of dexamethasone to anesthetized patients did not delay NMB reversal by sugammadex.

Trial registration

The trial was retrospectively registered with The Australian New Zealand Clinical Trials Registry (ANZCTR) on February 28th 2012 (enrollment of the first patient on February 2nd 2012) and was given a trial ID number ACTRN12612000245897 and universal trial number U1111-1128-5104.

The Effect of Intravenous Dexamethasone on Sugammadex Reversal Time in Children Undergoing Adenotonsillectomy

BACKGROUND

Dexamethasone has been shown to cause inhibition of sugammadex reversal in functionally innervated human muscle cells. In this prospective, double-blind, randomized, controlled study, we evaluated the effect of dexamethasone on the reversal time of sugammadex in children undergoing tonsillectomy and/or adenoidectomy.

METHODS

We recruited 60 patients with ASA physical status I to II, between the ages of 3 and 8 years, scheduled for elective tonsillectomy and/or adenoidectomy. After the induction of anesthesia, patients in group D received IV dexamethasone at a dose of 0.5 mg/kg within a total volume of 5 mL saline, whereas patients in group S received only 5 mL IV saline as the control group. At the end of surgery, all patients were given a single bolus dose (2 mg/kg) of sugammadex at reappearance of T2. Demographic data, hemodynamic variables, time to recovery (a train-of-four ratio of 0.9), time to tracheal extubation, and adverse effects were recorded.

RESULTS

There was no statistical significance between 2 groups in time to recovery and time to extubation. Time to recovery was 97.7 ± 23.9 seconds in group D and 91.1 ± 39.5 seconds in group S (P = 0.436; 95% confidence interval, -10.3 to 23.5). Time to extubation was 127.9 ± 23.2 seconds and 123.8 ± 38.7 seconds in group D and in group S, respectively (P = 0.612; 95% confidence interval, -11.9 to 20.05).

CONCLUSIONS

IV dexamethasone, given after induction of anesthesia, at a dose of 0.5 mg/kg, does not substantively affect the reversal time of sugammadex in pediatric patients undergoing adenoidectomy and/or tonsillectomy.

Sugammadex: What do we Know and What do we Still Need to Know? A Review of the Recent (2013 to 2014) Literature

Since its launch in 2008, sugammadex has been considered one of the most significant developments in anaesthesia-related pharmacology. With almost 500 sugammadex-related publications and over nine million patient exposures worldwide, user experience and scientific data have grown exponentially. However, several important questions are yet to be answered. This article reviews the sugammadex-related literature in 2013 and 2014 to determine which of these questions have been answered more fully over the last 18 months and which questions require more information and research.

Dexamethasone produces dose-dependent inhibition of sugammadex reversal in in vitro innervated primary human muscle cells

BACKGROUND

Corticosteroids are frequently used during anesthesia to provide substitution therapy in patients with adrenal insufficiency, as a first-line treatment of several life-threatening conditions, to prevent postoperative nausea and vomiting, and as a component of multimodal analgesia. For these last 2 indications, dexamethasone is most frequently used. Due to the structural resemblance between aminosteroid muscle relaxants and dexamethasone, concerns have been raised about possible corticosteroid inhibition in the reversal of neuromuscular block by sugammadex. We thus investigated the influence of dexamethasone on sugammadex reversal of rocuronium-induced neuromuscular block, which could be relevant in certain clinical situations.

METHODS

The unique co-culture model of human muscle cells innervated in vitro with rat embryonic spinal cord explants to form functional neuromuscular junctions was first used to explore the effects of 4 and 10 μM rocuronium on muscle contractions, as quantitatively evaluated by counting contraction units in contraction-positive explant co-cultures. Next, equimolar and 3-fold equimolar sugammadex was used to investigate the recovery of contractions from 4 and 10 μM rocuronium block. Finally, 1, 100, and 10 μM dexamethasone (normal, elevated, and high clinical levels) were used to evaluate any effects on the reversal of rocuronium-induced neuromuscular block by sugammadex.

RESULTS

Seventy-eight explant co-cultures from 3 time-independent experiments were included, where the number of contractions increased to 10 days of co-culturing. Rocuronium showed a time-dependent effect on depth of neuromuscular block (4 μM rocuronium: baseline, 10, 20 minutes administration; P < 0.0001), while the dose-dependent effect was close to nominal statistical significance (4, 10 μM; P = 0.080). This was reversed by equimolar concentrations of sugammadex, with further and virtually complete recovery of contractions with 3-fold equimolar sugammadex (P < 0.0001). Dexamethasone diminished 10 μM sugammadex-induced recovery of contractions from rocuronium-induced neuromuscular block in a dose-dependent manner (P = 0.026) with a higher sugammadex concentration (30 μM) being close to statistically significantly improving recovery (P = 0.065). The highest concentration of dexamethasone decreased the recovery of contractions by equimolar sugammadex by 26%; this effect was more pronounced when 3-fold equimolar (30 μM) sugammadex was used for reversal (48%).

CONCLUSIONS

This is the first report in which the effects of rocuronium and sugammadex interactions with dexamethasone have been studied in a highly accessible in vitro experimental model of functionally innervated human muscle cells. Sugammadex reverses rocuronium-induced neuromuscular block; however, concomitant addition of high dexamethasone concentrations diminishes the efficiency of sugammadex. Further studies are required to determine the clinical relevance of these interactions.

Non-synaptic roles of acetylcholinesterase and agrin

Proteins in living organisms have names that are usually derived from their function in the biochemical system their discoverer was investigating. Typical examples are acetylcholinesterase and agrin; however, for both of these, various other functions that are not related to the cholinergic system have been revealed. Our investigations have been focused on the alternative roles of acetylcholinesterase and agrin in the processes of muscle development and regeneration. Previously, we described a role for agrin in the development of excitability in muscle contraction. In this study, we report the effects of agrin on secretion of interleukin 6 in developing human muscle. At the myoblast stage, agrin increases interleukin 6 secretion. This effect seems to be general as it was observed in all of the cell models analysed (human, mouse, cell lines). After fusion of myoblasts into myotubes, the effects of agrin are no longer evident, although agrin has further effects at the innervation stage, at least in in vitro innervated human muscle. These effects of agrin are another demonstration of its non-synaptic roles that are apparently developmental-stage specific. Our data support the view that acetylcholinesterase and agrin participate in various processes during development of skeletal muscle.