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Jiang S, Fu W, Wang S, Zhu G, Wang J, Ma Y. Bacterial Outer Membrane Vesicles Loaded with Perhexiline Suppress Tumor Development by Regulating Tumor-Associated Macrophages Repolarization in a Synergistic Way. Int J Mol Sci 2023; 24:11222. [PMID: 37446401 DOI: 10.3390/ijms241311222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/30/2023] [Accepted: 07/04/2023] [Indexed: 07/15/2023] Open
Abstract
Tumor-associated macrophages (TAMs) promote tumor development and metastasis and are categorized into M1-like macrophages, suppressing tumor cells, and M2-like macrophages. M2-like macrophages, occupying a major role in TAMs, can be repolarized into anti-tumoral phenotypes. In this study, outer membrane vesicles (OMVs) secreted by Escherichia coli Nissle 1917 carry perhexiline (OMV@Perhx) to explore the influence of OMVs and perhexiline on TAM repolarization. OMV@Perhx was internalized by macrophages and regulated the phenotype of TAMs from M2-like to M1-like efficiently to increase the level of tumor suppressor accordingly. Re-polarized macrophages promoted apoptosis and inhibited the mobility of tumor, cells including invasion and migration. The results indicate that OMVs improve the efficacy of perhexiline and also represent a promising natural immunomodulator. Combining OMVs with perhexiline treatments shows powerfully synergistic anti-tumor effects through co-culturing with re-polarized macrophages. This work is promising to exploit the extensive applications of OMVs and chemical drugs, therefore developing a meaningful drug carrier and immunomodulator as well as expanding the purposes of traditional chemical drugs.
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Affiliation(s)
- Shoujin Jiang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Wei Fu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Sijia Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Guanshu Zhu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
- Guangdong Provincial Key Laboratory of Fermentation and Enzyme Engineering, South China University of Technology, Guangzhou 510006, China
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2
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Dhakal B, Tomita Y, Drew P, Price T, Maddern G, Smith E, Fenix K. Perhexiline: Old Drug, New Tricks? A Summary of Its Anti-Cancer Effects. Molecules 2023; 28:molecules28083624. [PMID: 37110858 PMCID: PMC10145508 DOI: 10.3390/molecules28083624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 04/17/2023] [Accepted: 04/17/2023] [Indexed: 04/29/2023] Open
Abstract
Cancer metabolic plasticity, including changes in fatty acid metabolism utilisation, is now widely appreciated as a key driver for cancer cell growth, survival and malignancy. Hence, cancer metabolic pathways have been the focus of much recent drug development. Perhexiline is a prophylactic antianginal drug known to act by inhibiting carnitine palmitoyltransferase 1 (CPT1) and 2 (CPT2), mitochondrial enzymes critical for fatty acid metabolism. In this review, we discuss the growing evidence that perhexiline has potent anti-cancer properties when tested as a monotherapy or in combination with traditional chemotherapeutics. We review the CPT1/2 dependent and independent mechanisms of its anti-cancer activities. Finally, we speculate on the clinical feasibility and utility of repurposing perhexiline as an anti-cancer agent, its limitations including known side effects and its potential added benefit of limiting cardiotoxicity induced by other chemotherapeutics.
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Affiliation(s)
- Bimala Dhakal
- Discipline of Surgery, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
| | - Yoko Tomita
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
- Medical Oncology, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Paul Drew
- Discipline of Surgery, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
| | - Timothy Price
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
- Medical Oncology, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
- Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Guy Maddern
- Discipline of Surgery, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
| | - Eric Smith
- Discipline of Surgery, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
- Medical Oncology, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
| | - Kevin Fenix
- Discipline of Surgery, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia
- Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, Adelaide, SA 5011, Australia
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3
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Dhakal B, Li CMY, Li R, Yeo K, Wright JA, Gieniec KA, Vrbanac L, Sammour T, Lawrence M, Thomas M, Lewis M, Perry J, Worthley DL, Woods SL, Drew P, Sallustio BC, Smith E, Horowitz JD, Maddern GJ, Licari G, Fenix K. The Antianginal Drug Perhexiline Displays Cytotoxicity against Colorectal Cancer Cells In Vitro: A Potential for Drug Repurposing. Cancers (Basel) 2022; 14:cancers14041043. [PMID: 35205791 PMCID: PMC8869789 DOI: 10.3390/cancers14041043] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/02/2022] [Accepted: 02/05/2022] [Indexed: 01/05/2023] Open
Abstract
Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. Perhexiline, a prophylactic anti-anginal drug, has been reported to have anti-tumour effects both in vitro and in vivo. Perhexiline as used clinically is a 50:50 racemic mixture ((R)-P) of (-) and (+) enantiomers. It is not known if the enantiomers differ in terms of their effects on cancer. In this study, we examined the cytotoxic capacity of perhexiline and its enantiomers ((-)-P and (+)-P) on CRC cell lines, grown as monolayers or spheroids, and patient-derived organoids. Treatment of CRC cell lines with (R)-P, (-)-P or (+)-P reduced cell viability, with IC50 values of ~4 µM. Treatment was associated with an increase in annexin V staining and caspase 3/7 activation, indicating apoptosis induction. Caspase 3/7 activation and loss of structural integrity were also observed in CRC cell lines grown as spheroids. Drug treatment at clinically relevant concentrations significantly reduced the viability of patient-derived CRC organoids. Given these in vitro findings, perhexiline, as a racemic mixture or its enantiomers, warrants further investigation as a repurposed drug for use in the management of CRC.
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Affiliation(s)
- Bimala Dhakal
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Celine Man Ying Li
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Runhao Li
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
- Medical Oncology, The Queen Elizabeth Hospital, Woodville, SA 5011, Australia
| | - Kenny Yeo
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Josephine A. Wright
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
| | - Krystyna A. Gieniec
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
- Department of Medical Specialties, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Laura Vrbanac
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
- Department of Medical Specialties, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Tarik Sammour
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
- Department of Medical Specialties, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
- Colorectal Unit, Department of Surgery, Royal Adelaide Hospital, Adelaide, SA 5005, Australia; (M.L.); (M.T.); (M.L.); (J.P.)
| | - Matthew Lawrence
- Colorectal Unit, Department of Surgery, Royal Adelaide Hospital, Adelaide, SA 5005, Australia; (M.L.); (M.T.); (M.L.); (J.P.)
| | - Michelle Thomas
- Colorectal Unit, Department of Surgery, Royal Adelaide Hospital, Adelaide, SA 5005, Australia; (M.L.); (M.T.); (M.L.); (J.P.)
| | - Mark Lewis
- Colorectal Unit, Department of Surgery, Royal Adelaide Hospital, Adelaide, SA 5005, Australia; (M.L.); (M.T.); (M.L.); (J.P.)
| | - Joanne Perry
- Colorectal Unit, Department of Surgery, Royal Adelaide Hospital, Adelaide, SA 5005, Australia; (M.L.); (M.T.); (M.L.); (J.P.)
| | - Daniel L. Worthley
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
| | - Susan L. Woods
- Precision Medicine, South Australian Health and Medical Research Institute, Adelaide, SA 5005, Australia; (J.A.W.); (K.A.G.); (L.V.); (T.S.); (D.L.W.); (S.L.W.)
- Department of Medical Specialties, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Paul Drew
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Benedetta C. Sallustio
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
- Discipline of Pharmacology, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Eric Smith
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
- Medical Oncology, The Queen Elizabeth Hospital, Woodville, SA 5011, Australia
| | - John D. Horowitz
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Guy J. Maddern
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
| | - Giovanni Licari
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
- Discipline of Pharmacology, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia
- Correspondence: (G.L.); (K.F.)
| | - Kevin Fenix
- Department of Surgery, Adelaide Medical School, The University of Adelaide, Adelaide, SA 5005, Australia; (B.D.); (C.M.Y.L.); (R.L.); (K.Y.); (P.D.); (E.S.); (G.J.M.)
- The Basil Hetzel Institute for Translational Health Research, The Queen Elizabeth Hospital, The University of Adelaide, Woodville, SA 5011, Australia; (B.C.S.); (J.D.H.)
- Correspondence: (G.L.); (K.F.)
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Midei MG, Darpo B, Ayers G, Brown R, Couderc JP, Daly W, Ferber G, Sager PT, Camm AJ. Electrophysiological and ECG Effects of Perhexiline, a Mixed Cardiac Ion Channel Inhibitor, Evaluated in Nonclinical Assays and in Healthy Subjects. J Clin Pharmacol 2021; 61:1606-1617. [PMID: 34214210 DOI: 10.1002/jcph.1934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 06/28/2021] [Indexed: 11/10/2022]
Abstract
Perhexiline has been used to treat hypertrophic cardiomyopathy. In addition to its effect on carnitine-palmitoyltransferase-1, it has mixed ion channel effects through inhibition of several cardiac ion currents. Effects on cardiac ion channels expressed in mammalian cells were assayed using a manual patch-clamp technique, action potential duration (APD) was measured in ventricular trabeculae of human donor hearts, and electrocardiogram effects were evaluated in healthy subjects in a thorough QT (TQT) study. Perhexiline blocked several cardiac ion currents at concentrations within the therapeutic range (150-600 ng/mL) with IC50 for hCav1.2 ∼ hERG < late hNav1.5. A significant APD shortening was observed in perhexiline-treated cardiomyocytes. The TQT study was conducted with a pilot part in 9 subjects to evaluate a dosing schedule that would achieve therapeutic and supratherapeutic perhexiline plasma concentrations on days 4 and 6, respectively. Guided by the results from the pilot, 104 subjects were enrolled in a parallel-designed part with a nested crossover comparison for the positive control. Perhexiline caused QTc prolongation, with the largest effect on ΔΔQTcF, 14.7 milliseconds at therapeutic concentrations and 25.6 milliseconds at supratherapeutic concentrations and a positive and statistically significant slope of the concentration-ΔΔQTcF relationship (0.018 milliseconds per ng/mL; 90%CI, 0.0119-0.0237 milliseconds per ng/mL). In contrast, the JTpeak interval was shortened with a negative concentration-JTpeak relationship, a pattern consistent with multichannel block. Further studies are needed to evaluate whether this results in a low proarrhythmic risk.
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Affiliation(s)
| | | | | | | | | | | | - Georg Ferber
- Statistik Georg Ferber GmbH, Riehen, Switzerland
| | - Philip T Sager
- Department of Medicine, Cardiovascular Research Institute, Stanford University, Palo Alto, California, USA
| | - A John Camm
- Division of Clinical Sciences, Cardiovascular and Cell Sciences Research Institute, St George's University of London, London, UK
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5
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Rathore R, Van Tine B. Targeting one-carbon metabolism requires mTOR inhibition: a new therapeutic approach in osteosarcoma. Mol Cell Oncol 2021; 8:1902250. [PMID: 34027041 PMCID: PMC8128185 DOI: 10.1080/23723556.2021.1902250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The rate-limiting enzyme of serine biosynthesis, 3-phosphoglycerate dehydrogenase (PHGDH), contributes to rapid growth and proliferation when it is overexpressed in cancer. We recently described the metabolic adaptations that occur upon PHGDH inhibition in osteosarcoma. PHGDH inhibition causes metabolite accumulation that activates the mechanistic target of rapamycin (mTOR) signaling, sensitizing osteosarcoma to non-rapalog mTOR inhibition.
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Affiliation(s)
- Richa Rathore
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Brian Van Tine
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, USA.,Division of Pediatric Hematology and Oncology, Children's Hospital, St. Louis, Missouri, USA.,Siteman Cancer Center, St. Louis, Missouri, USA
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6
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Rathore R, Caldwell KE, Schutt C, Brashears CB, Prudner BC, Ehrhardt WR, Leung CH, Lin H, Daw NC, Beird HC, Giles A, Wang WL, Lazar AJ, Chrisinger JSA, Livingston JA, Van Tine BA. Metabolic compensation activates pro-survival mTORC1 signaling upon 3-phosphoglycerate dehydrogenase inhibition in osteosarcoma. Cell Rep 2021; 34:108678. [PMID: 33503424 PMCID: PMC8552368 DOI: 10.1016/j.celrep.2020.108678] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 11/03/2020] [Accepted: 12/20/2020] [Indexed: 12/11/2022] Open
Abstract
Osteosarcoma is the most common pediatric and adult primary malignant bone cancer. Curative regimens target the folate pathway, downstream of serine metabolism, with high-dose methotrexate. Here, the rate-limiting enzyme in the biosynthesis of serine from glucose, 3-phosphoglycerate dehydrogenase (PHGDH), is examined, and an inverse correlation between PHGDH expression and relapse-free and overall survival in osteosarcoma patients is found. PHGDH inhibition in osteosarcoma cell lines attenuated cellular proliferation without causing cell death, prompting a robust metabolic analysis to characterize pro-survival compensation. Using metabolomic and lipidomic profiling, cellular response to PHGDH inhibition is identified as accumulation of unsaturated lipids, branched chain amino acids, and methionine cycle intermediates, leading to activation of pro-survival mammalian target of rapamycin complex 1 (mTORC1) signaling. Increased mTORC1 activation sensitizes cells to mTORC1 pathway inhibition, resulting in significant, synergistic cell death in vitro and in vivo. Identifying a therapeutic combination for PHGDH-high cancers offers preclinical justification for a dual metabolism-based combination therapy for osteosarcoma.
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Affiliation(s)
- Richa Rathore
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Katharine E Caldwell
- Department of Surgery, Division of Hepatobiliary Surgery, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Charles Schutt
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Caitlyn B Brashears
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Bethany C Prudner
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - William R Ehrhardt
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Cheuk Hong Leung
- Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Heather Lin
- Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Najat C Daw
- Division of Pediatrics, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Hannah C Beird
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Abigail Giles
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - Wei-Lien Wang
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Alexander J Lazar
- Department of Genomic Medicine, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - John S A Chrisinger
- Department of Pathology and Immunology, Washington University in St. Louis, St. Louis, MO 63110, USA
| | - J Andrew Livingston
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Sarcoma Medical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Brian A Van Tine
- Department of Medicine, Division of Medical Oncology, Washington University in St. Louis, St. Louis, MO 63110, USA; Siteman Cancer Center, St. Louis, MO 63110, USA.
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Abstract
Energy homeostasis during fasting or prolonged exercise depends on mitochondrial fatty acid oxidation (FAO). This pathway is crucial in many tissues with high energy demand and its disruption results in inborn FAO deficiencies. More than 15 FAO genetic defects have been currently described, and pathological variants described in circumpolar populations provide insights into its critical role in metabolism. The use of fatty acids as energy requires more than 2 dozen enzymes and transport proteins, which are involved in the activation and transport of fatty acids into the mitochondria. As the key rate-limiting enzyme of FAO, carnitine palmitoyltransferase I (CPT1) regulates FAO and facilitates adaptation to the environment, both in health and in disease, including cancer. The CPT1 family of proteins contains 3 isoforms: CPT1A, CPT1B, and CPT1C. This review focuses on CPT1A, the liver isoform that catalyzes the rate-limiting step of converting acyl-coenzyme As into acyl-carnitines, which can then cross membranes to get into the mitochondria. The regulation of CPT1A is complex and has several layers that involve genetic, epigenetic, physiological, and nutritional modulators. It is ubiquitously expressed in the body and associated with dire consequences linked with genetic mutations, metabolic disorders, and cancers. This makes CPT1A an attractive target for therapeutic interventions. This review discusses our current understanding of CPT1A expression, its role in heath and disease, and the potential for therapeutic opportunities targeting this enzyme.
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Affiliation(s)
- Isabel R Schlaepfer
- University of Colorado School of Medicine, Division of Medical Oncology, Aurora
| | - Molishree Joshi
- University of Colorado School of Medicine, Department of Pharmacology, Aurora, Colorado
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Licari G, Milne RW, Somogyi AA, Sallustio BC. Enantioselectivity in the tissue distribution of perhexiline contributes to different effects on hepatic histology and peripheral neural function in rats. Pharmacol Res Perspect 2018; 6:e00406. [PMID: 29864243 PMCID: PMC5980244 DOI: 10.1002/prp2.406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/23/2018] [Indexed: 11/10/2022] Open
Abstract
Perhexiline, a chiral drug, is a potent antiischemic agent whose clinical utility is limited by hepatic and neural toxicities. It inhibits mitochondrial carnitine palmitoyltransferase-1, however, excessive inhibition predisposes toward tissue steatosis. This pilot study investigated the distribution of the two enantiomers and their toxicological potential. Dark Agouti rats (n = 4 per group) were administered vehicle or 200 mg/kg daily of racemic, (+)- or (-)-perhexiline maleate orally for 8 weeks. Plasma biochemical liver function tests and Von Frey assessments of peripheral neural function were performed. Hepatic and neuronal histology, including lipid and glycogen content, was assessed using electron microscopy. Concentrations of the perhexiline enantiomers and metabolites were quantified in plasma, liver and heart. Plasma perhexiline concentrations following administration of racemate, (+)- or (-)-enantiomer were within the mid-upper clinical therapeutic range. There was extensive uptake of both enantiomers into liver and heart, with 2.5- to 4.5-fold greater net uptake of (+)- compared to (-)-perhexiline (P < .05) when administered as pure enantiomers, but not when administered as racemate. There was no biochemical or gross histological evidence of hepatotoxicity. However, livers of animals administered (+)-perhexiline had higher lipid (P < .01) and lower glycogen (P < .05) content, compared to those administered (-)-perhexiline. Animals administered racemic perhexiline had reduced peripheral neural function (P < .05) compared to controls or animals administered (-)-perhexiline. For the same plasma concentrations, differences in tissue distribution may contribute to disparities in the effects of (+)- and (-)-perhexiline on hepatic histology and neural function.
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Affiliation(s)
- Giovanni Licari
- Discipline of PharmacologyUniversity of AdelaideAdelaideSouth AustraliaAustralia
| | - Robert W. Milne
- School of Pharmacy and Medical ScienceUniversity of South AustraliaAdelaideSouth AustraliaAustralia
| | - Andrew A. Somogyi
- Discipline of PharmacologyUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Department of Clinical PharmacologyRoyal Adelaide HospitalAdelaideSouth AustraliaAustralia
| | - Benedetta C. Sallustio
- Discipline of PharmacologyUniversity of AdelaideAdelaideSouth AustraliaAustralia
- Department of Clinical PharmacologyThe Queen Elizabeth HospitalWoodvilleSouth AustraliaAustralia
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Steggall A, Mordi IR, Lang CC. Targeting Metabolic Modulation and Mitochondrial Dysfunction in the Treatment of Heart Failure. Diseases 2017; 5:E14. [PMID: 28933367 DOI: 10.3390/diseases5020014] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Revised: 04/21/2017] [Accepted: 04/27/2017] [Indexed: 12/11/2022] Open
Abstract
Despite significant improvements in morbidity and mortality with current evidence-based pharmaceutical-based treatment of heart failure (HF) over the previous decades, the burden of HF remains high. An alternative approach is currently being developed, which targets myocardial energy efficiency and the dysfunction of the cardiac mitochondria. Emerging evidence suggests that the insufficient availability of ATP to the failing myocardium can be attributed to abnormalities in the myocardial utilisation of its substrates rather than an overall lack of substrate availability. Therefore, the development of potential metabolic therapeutics has commenced including trimetazidine, ranolazine and perhexiline, as well as specific mitochondrial-targeting pharmaceuticals, such as elamipretide. Large randomised controlled trials are required to confirm the role of metabolic-modulating drugs in the treatment of heart failure, but early studies have been promising in their possible efficacy for the management of heart failure in the future.
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Abstract
INTRODUCTION Angina pectoris, or symptomatic myocardial ischaemia, reflects an impairment of coronary blood flow, and usually a deficiency of available myocardial energetics. Treatment options vary with the precise cause, which may vary with regards to the roles of increased myocardial oxygen demand versus reduced supply. Traditionally, organic nitrates, β-adrenoceptor antagonists, and non-dihydropyridine calcium antagonists were the only commonly used prophylactic anti-anginal agents. However, many patients failed to respond adequately to such therapy, and/or were unsuitable for their use. Areas covered: A number of 'new' agents have been shown to represent ancillary forms of prophylactic anti-anginal therapy and are particularly useful in patients who are relatively unsuitable for either percutaneous or surgical revascularisation. These include modulators of myocardial metabolic efficiency, such as perhexiline, trimetazidine and ranolazine, as well as high dose allopurinol, nicorandil and ivabradine. The advantages and disadvantages of these various agents are summarized. Expert opinion: 'Optimal' medical treatment of angina pectoris now includes use of agents primarily intended to reduce risk of infarction (e.g. statins, aspirin, ACE inhibitors). In patients whose angina persists despite the use of 'standard' anti-anginal therapy, and who are not ideal for invasive revascularization options, a number of emerging drugs offer prospects of symptomatic relief.
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Affiliation(s)
- Cher-Rin Chong
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia.,b Pharmacy Department , Queen Elizabeth Hospital , Woodville South , SA , Australia
| | - Gao J Ong
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia
| | - John D Horowitz
- a Cardiology and Clinical Pharmacology Departments, Basil Hetzel Institute , Queen Elizabeth Hospital, University of Adelaide , Adelaide , SA , Australia
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11
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Abstract
Activation of the neuro-hormonal system is a pathophysiological consequence of heart failure. Neuro-hormonal activation promotes metabolic changes, such as insulin resistance, and determines an increased use of non-carbohydrate substrates for energy production. Fasting blood ketone bodies as well as fat oxidation are increased in patients with heart failure, yielding a state of metabolic inefficiency. The net result is additional depletion of myocardial adenosine triphosphate, phosphocreatine and creatine kinase levels with further decreased efficiency of mechanical work. In this context, manipulation of cardiac energy metabolism by modification of substrate use by the failing heart has produced positive clinical results. The results of current research support the concept that shifting the energy substrate preference away from fatty acid metabolism and towards glucose metabolism could be an effective adjunctive treatment in patients with heart failure. The additional use of drugs able to partially inhibit fatty acids oxidation in patients with heart failure may therefore yield a significant protective effect for clinical symptoms and cardiac function improvement, and simultaneously ameliorate left ventricular remodelling. Certainly, to clarify the exact therapeutic role of metabolic therapy in heart failure, a large multicentre, randomised controlled trial should be performed.
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Singh S, Beadle R, Cameron D, Rudd A, Bruce M, Jagpal B, Schwarz K, Brindley G, Mckiddie F, Nightingale P, Lang C, Dawson D, Frenneaux M. Randomized double-blind placebo-controlled trial of perhexiline in heart failure with preserved ejection fraction syndrome. Future Cardiol 2015; 10:693-8. [PMID: 25495811 DOI: 10.2217/fca.14.62] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Recently heart failure with preserved ejection fraction (HFpEF) has emerged as a huge epidemic. Increasing evidence shows the role of energy deficiency in the pathophysiology of HFpEF. In the current study, we hypothesize that the use of metabolic modulator perhexiline would correct myocardial energy deficiency and improve exercise capacity and diastolic abnormalities in patients with this syndrome.
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Affiliation(s)
- Satnam Singh
- School of Medicine & Dentistry, University of Aberdeen, Polwarth Building, Aberdeen, AB25 2ZD, Scotland, UK
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13
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Singh S, Schwarz K, Horowitz J, Frenneaux M. Cardiac energetic impairment in heart disease and the potential role of metabolic modulators: a review for clinicians. ACTA ACUST UNITED AC 2015; 7:720-8. [PMID: 25518045 DOI: 10.1161/circgenetics.114.000221] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiac energetic impairment is a frequent finding in patients with both inherited and acquired diseases of heart muscle. In this review the mechanisms of energy generation in the healthy heart and their disturbances in heart muscle diseases are described. Therapeutic agents targeted at correcting cardiac energetic impairment are discussed.
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Affiliation(s)
- Satnam Singh
- From the Department of Cardiovascular Medicine, University of Aberdeen, Aberdeen, United Kingdom (S.S., K.S., M.F.); and Cardiology Unit, The Queen Elizabeth Hospital, Adelaide, Australia (J.H.)
| | - Konstantin Schwarz
- From the Department of Cardiovascular Medicine, University of Aberdeen, Aberdeen, United Kingdom (S.S., K.S., M.F.); and Cardiology Unit, The Queen Elizabeth Hospital, Adelaide, Australia (J.H.)
| | - John Horowitz
- From the Department of Cardiovascular Medicine, University of Aberdeen, Aberdeen, United Kingdom (S.S., K.S., M.F.); and Cardiology Unit, The Queen Elizabeth Hospital, Adelaide, Australia (J.H.)
| | - Michael Frenneaux
- From the Department of Cardiovascular Medicine, University of Aberdeen, Aberdeen, United Kingdom (S.S., K.S., M.F.); and Cardiology Unit, The Queen Elizabeth Hospital, Adelaide, Australia (J.H.).
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14
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Drury NE, Licari G, Chong CR, Howell NJ, Frenneaux MP, Horowitz JD, Pagano D, Sallustio BC. Relationship between plasma, atrial and ventricular perhexiline concentrations in humans: insights into factors affecting myocardial uptake. Br J Clin Pharmacol 2015; 77:789-95. [PMID: 24117487 DOI: 10.1111/bcp.12254] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 09/22/2013] [Indexed: 11/28/2022] Open
Abstract
AIM Little is known regarding the steady-state uptake of drugs into the human myocardium. Perhexiline is a prophylactic anti-anginal drug which is increasingly also used in the treatment of heart failure and hypertrophic cardiomyopathy. We explored the relationship between plasma perhexiline concentrations and its uptake into the myocardium. METHODS Blood, right atrium ± left ventricle biopsies were obtained from patients treated with perhexiline for a median of 8.5 days before undergoing coronary surgery in the perhexiline arm of a randomized controlled trial. Perhexiline concentrations in plasma and heart tissue were determined by HPLC. RESULTS Atrial biopsies were obtained from 94 patients and ventricular biopsies from 28 patients. The median plasma perhexiline concentration was within the therapeutic range at 0.24 mg l⁻¹ (IQR 0.12-0.44), the median atrial concentration was 6.02 mg kg⁻¹ (IQR 2.70-9.06) and median ventricular concentration was 10.0 mg kg⁻¹ (IQR 5.76-13.1). Atrial (r² = 0.76) and ventricular (r² = 0.73) perhexiline concentrations were closely and directly correlated with plasma concentrations (both P < 0.001). The median atrial : plasma ratio was 21.5 (IQR 18.1-27.1), ventricular : plasma ratio was 34.9 (IQR 24.5-55.2) and ventricular : atrial ratio was 1.67 (IQR 1.39-2.22). Using multiple regression, the best model for predicting steady-state atrial concentration included plasma perhexiline, heart rate and age (r² = 0.83). Ventricular concentrations were directly correlated with plasma perhexiline concentration and length of therapy (r² = 0.84). CONCLUSIONS This study demonstrates that plasma perhexiline concentrations are predictive of myocardial drug concentrations, a major determinant of drug effect. However, net myocardial perhexiline uptake is significantly modulated by patient age, potentially via alteration of myocardial:extracardiac drug uptake.
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Affiliation(s)
- Nigel E Drury
- Departments of Clinical Pharmacology and Cardiology, Basil Hetzel Institute, The Queen Elizabeth Hospital, Woodville, SA, Australia; The Discipline of Surgery, University of Adelaide, Adelaide, SA, Australia; Department of Cardiothoracic Surgery, Queen Elizabeth Hospital, Birmingham, UK
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15
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16
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Beadle RM, Williams LK, Kuehl M, Bowater S, Abozguia K, Leyva F, Yousef Z, Wagenmakers AJM, Thies F, Horowitz J, Frenneaux MP. Improvement in cardiac energetics by perhexiline in heart failure due to dilated cardiomyopathy. JACC Heart Fail 2015; 3:202-11. [PMID: 25650370 DOI: 10.1016/j.jchf.2014.09.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/05/2014] [Accepted: 09/19/2014] [Indexed: 11/19/2022]
Abstract
OBJECTIVES The aim of this study was to determine whether short-term treatment with perhexiline improves cardiac energetics, left ventricular function, and symptoms of heart failure by altering cardiac substrate utilization. BACKGROUND Perhexiline improves exercise capacity and left ventricular ejection fraction (LVEF) in patients with heart failure (HF). (31)P cardiac magnetic resonance spectroscopy can be used to quantify the myocardial phosphocreatine/adenosine triphosphate ratio. Because improvement of HF syndrome can improve cardiac energetics secondarily, we investigated the effects of short-term perhexiline therapy. METHODS Patients with systolic HF of nonischemic etiology (n = 50, 62 ± 1.8 years of age, New York Heart Association functional class II to IV, LVEF: 27.0 ± 1.44%) were randomized to receive perhexiline 200 mg or placebo for 1 month in a double-blind fashion. Clinical assessment, echocardiography, and (31)P cardiac magnetic resonance spectroscopy were performed at baseline and after 1 month. A substudy of 22 patients also underwent cross-heart blood sampling at completion of the study to quantify metabolite utilization. RESULTS Perhexiline therapy was associated with a 30% increase in the phosphocreatine/adenosine triphosphate ratio (from 1.16 ± 0.39 to 1.51 ± 0.51; p < 0.001) versus a 3% decrease with placebo (from 1.36 ± 0.31 to 1.34 ± 0.31; p = 0.37). Perhexiline therapy also led to an improvement in New York Heart Association functional class compared with placebo (p = 0.036). Short-term perhexiline therapy did not change LVEF. Cross-heart measures of cardiac substrate uptake and respiratory exchange ratio (which reflects the ratio of substrates used) did not differ between patients who received perhexiline versus placebo. CONCLUSIONS Perhexiline improves cardiac energetics and symptom status with no evidence of altered cardiac substrate utilization. No change in LVEF is seen at this early stage. (Metabolic Manipulation in Chronic Heart Failure; NCT00841139).
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Affiliation(s)
- Roger M Beadle
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen, Scotland
| | - Lynne K Williams
- Department of Cardiology, Toronto General Hospital, Toronto, Ontario, Canada
| | - Michael Kuehl
- Department of Cardiovascular Medicine, University of Birmingham, Birmingham, England
| | - Sarah Bowater
- Department of Cardiovascular Medicine, University of Birmingham, Birmingham, England
| | - Khalid Abozguia
- Department of Cardiovascular Medicine, University of Birmingham, Birmingham, England
| | - Francisco Leyva
- Department of Cardiovascular Medicine, University of Birmingham, Birmingham, England
| | - Zaheer Yousef
- Department of Cardiology, University Hospital of Wales, Cardiff, Wales
| | - Anton J M Wagenmakers
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, England
| | - Frank Thies
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen, Scotland
| | - John Horowitz
- Department of Cardiology and Pharmacology, The Queen Elizabeth Hospital, Woodville, South Australia, Australia
| | - Michael P Frenneaux
- School of Medicine and Dentistry, University of Aberdeen, Aberdeen, Scotland.
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Abstract
Although our current appreciation of the detrimental role of neurohumoral activation in heart failure (HF) has been intellectually appealing and has led to neurohumoral antagonism that has reduced morbidity and mortality from HF, the persisting disability and death rates remain unacceptably high. In the search for novel strategies to improve on these outcomes, we must reacquaint ourselves with basic cardiac physiology at levels ranging from the molecular to the systemic in order to identify new targets for the treatment of HF. This approach has already begun to yield results; in this review, two such aspects will be focused on: diastolic ventricular interaction and cardiac energetics. These two examples will be used to illuminate how fundamental research has elucidated age-old, although mechanistically elusive, principles (for example, the Frank-Starling law), explained why existing and emerging therapeutic approaches (for example, biventricular pacing in HF) have proved successful, and successfully identified novel therapy modes (for example, perhexiline as an energy augmentation agent).
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Davies BJ, Herbert MK, Coller JK, Somogyi AA, Milne RW, Sallustio BC. Steady-state pharmacokinetics of the enantiomers of perhexiline in CYP2D6 poor and extensive metabolizers administered Rac-perhexiline. Br J Clin Pharmacol 2008; 65:347-54. [PMID: 17875193 PMCID: PMC2291239 DOI: 10.1111/j.1365-2125.2007.03015.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 06/20/2007] [Indexed: 11/28/2022] Open
Abstract
UNLABELLED What is already known about this subject. Perhexiline (PHX) is administered as a racemic mixture and exhibits enantioselective pharmacokinetics in both poor and extensive metabolizers of CYP2D6 (PM and EM, respectively). Extensive metabolism by CYP2D6 is primarily responsible for the observed enantioselectivity in EM, but the process responsible in PM is unknown. Analysis of the steady-state plasma concentration-time profiles of the enantiomers of PHX in PM and EM was undertaken in order to elucidate the observed enantioselectivity, particularly with respect to PM. What this study adds. This is the first study to examine the steady-state plasma concentration-time profiles of the enantiomers of PHX in EM and PM over the course of an interdosing interval. The apparent oral clearance of each enantiomer was calculated from their respective AUC rather than from trough concentrations and was enantioselective in both phenotypes, with higher apparent oral clearances of (-)-than (+)-PHX. Renal clearance, calculated for EM and subsequently assumed for PM, constitutes a greater proportion of the total apparent oral clearance of each enantiomer in PM than EM, but was not enantioselective and thus unable to explain the enantioselectivity observed in PM. AIMS To determine the steady-state pharmacokinetics of perhexiline (PHX) enantiomers over one interdosing interval in CYP2D6 extensive and poor metabolizer (EM and PM, respectively) patients administered rac-PHX. To elucidate the processes responsible for enantioselectivity, particularly in PM patients. METHODS Blood samples were taken over one interdosing interval from six EM and two PM patients at steady-state with respect to rac-PHX metabolism. Complete urine collections were taken from five EM patients. PHX concentrations in plasma and urine were determined with enantioselective high-performance liquid chromatography methods. RESULTS EM patients had 16- and 10-fold greater median apparent oral clearances of (+)- and (-)-PHX, respectively, than PM patients (P < 0.05 for both) and required significantly larger doses of rac-PHX (69 vs. 4.2 microg kg(-1) h(-1), P < 0.05) to maintain therapeutic concentrations in plasma. Patient phenotypes were consistent with CYP2D6 genotypes. Both groups displayed enantioselective pharmacokinetics, with higher apparent oral clearances for (-)-PHX compared with (+)-PHX, although PM patients exhibited significantly greater enantioselectivity (P < 0.05). The renal clearance of PHX enantiomers was not enantioselective and accounted for <1% of the median apparent oral clearance of each enantiomer in EM patients. Assuming the same renal clearances for PM patients accounts for approximately 9 and 4% of their median apparent oral clearances of (+)- and (-)-PHX, respectively. CONCLUSIONS The enantioselective pharmacokinetics of PHX are primarily due to metabolism by CYP2D6 in EM patients. The mechanism responsible for the enantioselective pharmacokinetics of PHX in PM patients is unknown, but may be due to enantioselective biliary or intestinal excretion.
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Affiliation(s)
- Benjamin J Davies
- Department of Cardiology and Clinical Pharmacology, The Queen Elizabeth Hospital, Woodville, South Australia, Australia
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19
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Abstract
AIMS The aims of this study were to examine the in vitro enzyme kinetics and CYP isoform selectivity of perhexiline monohydroxylation using human liver microsomes. METHODS Conversion of rac-perhexiline to monohydroxyperhexiline by human liver microsomes was assessed using a high-performance liquid chromatography assay with precolumn derivatization to measure the formation rate of the product. Isoform selective inhibitors were used to define the CYP isoform profile of perhexiline monohydroxylation. RESULTS The rate of perhexiline monohydroxylation with microsomes from 20 livers varied 50-fold. The activity in 18 phenotypic perhexiline extensive metabolizer (PEM) livers varied about five-fold. The apparent Km was 3.3 +/- 1.5 micro m, the Vmax was 9.1 +/- 3.1 pmol min-1 mg-1 microsomal protein and the in vitro intrinsic clearance (Vmax/Km) was 2.9 +/- 0.5 micro l min-1 mg-1 microsomal protein in the extensive metabolizer livers. The corresponding values in the poor metabolizer livers were: apparent Km 124 +/- 141 micro m; Vmax 1.4 +/- 0.6 pmol min-1 mg-1 microsomal protein; and intrinsic clearance 0.026 micro l min-1 mg-1 microsomal protein. Quinidine almost completely inhibited perhexiline monohydroxylation activity, but inhibitors selective for other CYP isoforms had little effect. CONCLUSIONS Perhexiline monohydroxylation is almost exclusively catalysed by CYP2D6 with activities being about 100-fold lower in CYP2D6 poor metabolizers than in extensive metabolizers. The in vitro data predict the in vivo saturable metabolism and pharmacogenetics of perhexiline.
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Affiliation(s)
- L B Sørensen
- Department of Clinical Pharmacology, Flinders Medical Centre and Flinders University of South Australia, Bedford Park, Australia
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20
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Abstract
AIMS 1) To develop an estimate of oral clearance (CL(Px)/F) for the antianginal agent perhexiline based on the ratio of cis-OH-perhexiline metabolite/parent perhexiline plasma concentrations at steady-state (C(OHPx,ss)/C(Px,ss)). 2) To determine whether the ratio measured in the first fortnight of treatment (C(i)(OHPx)/C(i)(Px)) may be used to guide patient dosing with perhexiline, a drug with a narrow therapeutic index, long half-life and saturable metabolism via CYP2D6. METHODS Two retrospective studies were conducted reviewing patient records and data obtained from routine monitoring of plasma perhexiline and cis-OH-perhexiline concentrations. RESULTS Study 1 (n=70). At steady-state, the frequency distributions of CL(Px)/F and C(OHPx,ss)/C(Px,ss) were consistent with CYP2D6 metabolism. Putative poor metabolizers (approximately 8%) were identified by CL(Px)/F< or =50 ml min(-1) or C(OHPx,ss)/C(Px,ss)< or =0.3. A group of patients with CL(Px)/F> or =950 ml min(-1) may have been ultra-rapid metabolizers. In this group, the high CL(Px)/F values suggest extensive first-pass metabolism and poor bioavailability. In patients with therapeutic plasma perhexiline concentrations (0.15-0.60 mg l(-1)), the variability in dose appeared directly proportional to CL(Px)/F (r2=0.741, P<0.0001). Study 2 (n=23). Using C(i)(OHPx)/C(i)(Px) patients were tentatively identified as poor, extensive and ultra-rapid metabolizers, with CL(Px)/F of 23-72, 134-868 and 947-1462 ml min(-1), respectively, requiring doses of 10-25, 100-250 and 300-500 mg day(-1), respectively. CONCLUSIONS The cis-OH-perhexiline/perhexiline concentration ratio may be useful for optimizing individual patient treatment with the antianginal agent perhexiline.
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Affiliation(s)
- Benedetta C Sallustio
- Department of Cardiology and Clinical Pharmacology, The Queen Elizabeth Hospital, Woodville 5011, South Australia.
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Walker BD, Valenzuela SM, Singleton CB, Tie H, Bursill JA, Wyse KR, Qiu MR, Breit SN, Campbell TJ. Inhibition of HERG channels stably expressed in a mammalian cell line by the antianginal agent perhexiline maleate. Br J Pharmacol 1999; 127:243-51. [PMID: 10369479 PMCID: PMC1565989 DOI: 10.1038/sj.bjp.0702502] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Perhexiline has been used as an anti-anginal agent for over 25 years, and is known to cause QT prolongation and torsades de pointes. We hypothesized that the cellular basis for these effects was blockade of I(Kr). A stable transfection of HERG into a CHO-K1 cell line produced a delayed rectifier, potassium channel with similar properties to those reported for transient expression in Xenopus oocytes. Perhexiline caused voltage- and frequency-dependent block of HERG (IC50 7.8 microM). The rate of inactivation was increased and there was a 10 mV hyperpolarizing shift in the voltage-dependence of steady-state inactivation, suggestive of binding to the inactivated state. In conclusion, perhexiline potently inhibits transfected HERG channels and this is the probable mechanism for QT prolongation and torsades de pointes. Channel blockade shows greatest affinity for the inactivated state.
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Affiliation(s)
- B D Walker
- Department of Clinical Pharmacology, University of New South Wales, Victor Chang Cardiac Research Institute, St Vincent's Hospital, Darlinghurst, Australia.
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