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Kaura V, Hopkins P. Recent advances in skeletal muscle physiology. BJA Educ 2024; 24:84-90. [PMID: 38375493 PMCID: PMC10874741 DOI: 10.1016/j.bjae.2023.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2023] [Indexed: 02/21/2024] Open
Affiliation(s)
- V. Kaura
- Leeds Institute of Medical Research at St James's, University of Leeds, UK
| | - P.M. Hopkins
- Leeds Institute of Medical Research at St James's, University of Leeds, UK
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Miyoshi H, Otsuki S, Mukaida K, Kido K, Sumii A, Ikeda T, Noda Y, Yasuda T, Narasaki S, Kato T, Kamiya S, Horikawa YT, Tsutsumi YM. Effects of Remimazolam on Intracellular Calcium Dynamics in Myotubes Derived from Patients with Malignant Hyperthermia and Functional Analysis of Type 1 Ryanodine Receptor Gene Variants. Genes (Basel) 2023; 14:2009. [PMID: 38002952 PMCID: PMC10671487 DOI: 10.3390/genes14112009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 10/20/2023] [Accepted: 10/24/2023] [Indexed: 11/26/2023] Open
Abstract
Remimazolam is a novel general anesthetic and its safety in patients with malignant hyperthermia (MH) is unknown. We used myotubes derived from the skeletal muscle of patients with MH to examine the response to ryanodine receptor 1 (RYR1) agonist and remimazolam in MH-susceptible patients. Patients underwent muscle biopsy for the Ca2+-induced Ca2+ release (CICR) rate test, a diagnostic tool for MH in Japan. Ten patients had myotubes obtained from skeletal muscle cultures, and the genes associated with malignant hyperthermia in these patients were analyzed. The EC50 of caffeine, cresol, and remimazolam to induce intracellular calcium concentration change were compared between myotubes from CICR-negative genetic test patients and myotubes from other patients. Eight of the ten were CICR-positive, five of whom had RYR1 causative gene mutations or variants. Two patients had CICR-negative genetic tests, and as expected had the highest EC50 (the concentration of a drug that gives a half-maximal response) in response to caffeine, 4CmC and remimazolam. Three patients had a positive CICR but no known variants in RYR1 or CACNA1S (voltage-gated calcium channel subunit alpha1S). Myotubes in these patients had significantly lower EC50s for all agents than myotubes in CICR-negative patients. When myotubes from a patient who was CICR-negative and had no gene variant were used as a control, myotubes from CICR-positive patients were more hyper-responsive than controls to all stimulants used. The EC50 for remimazolam was lowest for myotubes from CICR-positive, RYR1-mutant patients, at 206 µM (corresponding to 123 µg/mL). The concentration was more than 80-times higher than the clinical concentration. RYR1 gene variants in R4645Q and W5020G were shown to be causative gene mutations for MH. Intracellular calcium in myotubes from MH patients are elevated at high concentrations of remimazolam but not at clinically used concentrations of remimazolam. Remimazolam appears to be safe to use in patients with MH.
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Affiliation(s)
- Hirotsugu Miyoshi
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Sachiko Otsuki
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Keiko Mukaida
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Kenshiro Kido
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Ayako Sumii
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Tsuyoshi Ikeda
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Yuko Noda
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Toshimichi Yasuda
- Department of Anesthesiology, Hiroshima Prefectural Rehabilitation Center, Hiroshima 739-0036, Japan;
| | - Soshi Narasaki
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Takahiro Kato
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Satoshi Kamiya
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
| | - Yousuke T. Horikawa
- CHOC Health Alliance, Children’s Hospital Orange County, Orange, CA 92868, USA;
| | - Yasuo M. Tsutsumi
- Department of Anesthesiology and Critical Care, Hiroshima University, Hiroshima 734-8551, Japan; (S.O.); (K.M.); (K.K.); (A.S.); (T.I.); (Y.N.); (S.N.); (T.K.); (S.K.); (Y.M.T.)
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Osman V, Speigel I, Patel K, Hemmings HC. Isoflurane Alters Presynaptic Endoplasmic Reticulum Calcium Dynamics in Wild-Type and Malignant Hyperthermia-Susceptible Rodent Hippocampal Neurons. eNeuro 2023; 10:ENEURO.0114-23.2023. [PMID: 37591734 PMCID: PMC10467020 DOI: 10.1523/eneuro.0114-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 08/19/2023] Open
Abstract
Volatile anesthetics reduce excitatory synaptic transmission by both presynaptic and postsynaptic mechanisms which include inhibition of depolarization-evoked increases in presynaptic Ca2+ concentration and blockade of postsynaptic excitatory glutamate receptors. The presynaptic sites of action leading to reduced electrically evoked increases in presynaptic Ca2+ concentration and Ca2+-dependent exocytosis are unknown. Endoplasmic reticulum (ER) of Ca2+ release via ryanodine receptor 1 (RyR1) and uptake by SERCA are essential for regulation intracellular Ca2+ and are potential targets for anesthetic action. Mutations in sarcoplasmic reticulum (SR) release channels mediate volatile anesthetic-induced malignant hyperthermia (MH), a potentially fatal pharmacogenetic condition characterized by unregulated Ca2+ release and muscle hypermetabolism. However, the impact of MH mutations on neuronal function are unknown. We used primary cultures of postnatal hippocampal neurons to analyze volatile anesthetic-induced changes in ER Ca2+ dynamics using a genetically encoded ER-targeted fluorescent Ca2+ sensor in both rat and mouse wild-type (WT) neurons and in mouse mutant neurons harboring the RYR1 T4826I MH-susceptibility mutation. The volatile anesthetic isoflurane reduced both baseline and electrical stimulation-evoked increases in ER Ca2+ concentration in neurons independent of its depression of presynaptic cytoplasmic Ca2+ concentrations. Isoflurane and sevoflurane, but not propofol, depressed depolarization-evoked increases in ER Ca2+ concentration significantly more in mouse RYR1 T4826I mutant neurons than in wild-type neurons. The RYR1 T4826I mutant neurons also showed markedly greater isoflurane-induced reductions in presynaptic cytosolic Ca2+ concentration and synaptic vesicle (SV) exocytosis. These findings implicate RyR1 as a molecular target for the effects of isoflurane on presynaptic Ca2+ handling.
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Affiliation(s)
- Vanessa Osman
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
| | - Iris Speigel
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
| | - Kishan Patel
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
| | - Hugh C Hemmings
- Department of Pharmacology, Weill Cornell Medical College, New York, NY 10065
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY 10065
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Kalia LV, Nimmo GAM, Mestre TA. Genetic Testing in Clinical Movement Disorders: A Case-Based Review. Semin Neurol 2023; 43:147-155. [PMID: 36854393 DOI: 10.1055/s-0043-1763507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Genetics are fundamental to understanding the pathophysiology of neurological disease, including movement disorders. Genetic testing in clinical practice has changed dramatically over the last few decades. While the likelihood of establishing an etiological diagnosis is greater now with increased access to testing and more advanced technologies, clinicians face challenges when deciding whether to test, then selecting the appropriate test, and ultimately interpreting and sharing the results with patients and families. In this review, we use a case-based approach to cover core aspects of genetic testing for the neurologist, namely, genetic testing in Parkinson's disease, interpretation of inconclusive genetic test reports, and genetic testing for repeat expansion disorders using Huntington disease as a prototype.
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Affiliation(s)
- Lorraine V Kalia
- Division of Neurology, Department of Medicine, Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic and Krembil Research Institute, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada
| | - Graeme A M Nimmo
- Fred A. Litwin Family Centre for Genetic Medicine, Department of Medicine, Mount Sinai Hospital and Toronto General Hospital, University Health Network, University of Toronto, Toronto, Canada
| | - Tiago A Mestre
- Division of Neurology, Department of Medicine, Ottawa Hospital Research Institute, University of Ottawa Brain and Mind Research Institute, The Ottawa Hospital, Ottawa, Ontario Canada
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Sellers C, Woodman N. Inhalational induction in paediatric anaesthesia. BJA Educ 2023; 23:32-38. [PMID: 36601023 PMCID: PMC9805937 DOI: 10.1016/j.bjae.2022.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/27/2022] [Indexed: 12/13/2022] Open
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Uchiyama K, Sunaga H, Katori N, Uezono S. General anesthesia with remimazolam in a patient with clinically suspected malignant hyperthermia. JA Clin Rep 2021; 7:78. [PMID: 34657987 PMCID: PMC8520858 DOI: 10.1186/s40981-021-00482-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/04/2021] [Accepted: 10/09/2021] [Indexed: 12/13/2022] Open
Affiliation(s)
- Keita Uchiyama
- Department of Anesthesiology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi, Minatoku, Tokyo, 105-8461, Japan
| | - Hiroshi Sunaga
- Department of Anesthesiology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi, Minatoku, Tokyo, 105-8461, Japan.
| | - Nobuyuki Katori
- Department of Anesthesiology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi, Minatoku, Tokyo, 105-8461, Japan
| | - Shoichi Uezono
- Department of Anesthesiology, The Jikei University School of Medicine, 3-25-8 Nishishimbashi, Minatoku, Tokyo, 105-8461, Japan
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