{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,27]],"date-time":"2026-08-27T04:48:58Z","timestamp":1787806138583,"version":"build-2784847793"},"reference-count":82,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2025,10,24]],"date-time":"2025-10-24T00:00:00Z","timestamp":1761264000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["AI072648"],"award-info":[{"award-number":["AI072648"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["AR076092"],"award-info":[{"award-number":["AR076092"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["DK078922"],"award-info":[{"award-number":["DK078922"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100001026","name":"Central New York Community Foundation","doi-asserted-by":"crossref","id":[{"id":"10.13039\/100001026","id-type":"DOI","asserted-by":"crossref"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"crossref","award":["DK131849"],"award-info":[{"award-number":["DK131849"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>The reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) is a primary electron donor for both antioxidant enzymes, such as glutathione reductase, and pro-oxidant enzymes, such as NADPH oxidases that produce reactive oxygen species (ROS) and nitric oxide synthases that generate nitric oxide which act as signaling molecules. Monitoring NADPH levels, NADPH\/NADP+ ratio, and especially distinguishing from NADH, provides vital information about cellular redox status, energy generation, survival, lineage specification, and death pathway selection. NADPH detection is key to understanding metabolic reprogramming in cancer, aging, and cardiovascular, hormonal, neurodegenerative, and autoimmune diseases. Liquid chromatography combined with mass spectrometry (LC-MS) is crucial for NADPH detection in redox signaling because it offers the high sensitivity, specificity, and comprehensive profiling needed to quantify this vital but labile redox cofactor in complex biological samples. Using hepatoma cell lines, liver tissues, and primary hepatocytes from mice lacking transaldolase or nicotinamide nucleotide transhydrogenase, or having lupus, this study demonstrates that accurate measurement of NADPH depends on its preservation in reduced form which can be optimally achieved by extraction of metabolites in alkaline solution, such as 0.1 M potassium hydroxide (KOH) in comparison to 80% methanol (MeOH) alone or 40:40:20 methanol\/acetonitrile\/formic acid solution. While KOH extraction coupled with hydrophilic interaction liquid chromatography (HILIC) and mass spectrometry most reliably detects NADPH, NADP, NADH, NAD, polyamines, and polyols, MeOH extraction is best suited for detection of glutathione and overall discrimination between complex metabolite extracts. This study therefore supports performing parallel KOH and MeOH extractions to enable comprehensive metabolomic analysis of redox signaling.<\/jats:p>","DOI":"10.3390\/ijms262110371","type":"journal-article","created":{"date-parts":[[2025,10,27]],"date-time":"2025-10-27T00:51:42Z","timestamp":1761526302000},"page":"10371","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Potassium-Hydroxide-Based Extraction of Nicotinamide Adenine Dinucleotides from Biological Samples Offers Accurate Assessment of Intracellular Redox Status"],"prefix":"10.3390","volume":"26","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8147-0498","authenticated-orcid":false,"given":"Tamas","family":"Faludi","sequence":"first","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel","family":"Krakko","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jessica","family":"Nolan","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Hanczko","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Akshay","family":"Patel","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Microbiology and Immunology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Biochemistry and Molecular Biology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zach","family":"Oaks","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Microbiology and Immunology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Biochemistry and Molecular Biology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Evan","family":"Ruggiero","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joshua","family":"Lewis","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaojing","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ting-Ting","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Neurology, Stanford University, Palo Alto, CA 94304, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ibolya","family":"Molnar-Perl","sequence":"additional","affiliation":[{"name":"Institute of Chemistry, Department of Analytical Chemistry, L. E\u00f6tv\u00f6s University, H-1117 Budapest, Hungary"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5017-1348","authenticated-orcid":false,"given":"Andras","family":"Perl","sequence":"additional","affiliation":[{"name":"Department of Medicine, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Microbiology and Immunology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"},{"name":"Department of Biochemistry and Molecular Biology, Norton College of Medicine, State University of New York, Syracuse, NY 13210, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,10,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1042\/BJ20061638","article-title":"The power to reduce: Pyridine nucleotides\u2014Small molecules with a multitude of functions","volume":"402","author":"Pollak","year":"2007","journal-title":"Biochem. J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"13908","DOI":"10.1074\/jbc.274.20.13908","article-title":"Mechanisms of Protection of Catalase by NADPH: Kinetics and stochiometry","volume":"274","author":"Kirkman","year":"1999","journal-title":"J. Biol. Chem."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"395","DOI":"10.1016\/j.molmed.2011.01.014","article-title":"Oxidative stress, inflammation and carcinogenesis are controlled through the pentose phosphate pathway by transaldolase","volume":"7","author":"Perl","year":"2011","journal-title":"Trends Mol. Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"397","DOI":"10.1016\/0065-2571(69)90030-2","article-title":"Equilibrium relations between pyridine nucleotides and adenine nucleotides and their roles in the regulation of metabolic processes","volume":"7","author":"Krebs","year":"1969","journal-title":"Adv. Enzym. Regul."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"3161","DOI":"10.1002\/cphc.201500534","article-title":"Mechanostability of the Single-Electron-Transfer Complexes of Anabaena FerredoxinG\u00c7\u00f4NADP+ Reductase","volume":"16","author":"Marcuello","year":"2015","journal-title":"ChemPhysChem"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1291","DOI":"10.1152\/physrev.00034.2023","article-title":"NADPH oxidases: Redox regulation of cell homeostasis and disease","volume":"105","author":"Lopes","year":"2025","journal-title":"Physiol. Rev."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Bouchard, M., McAllister, A., Bourlett, N.S., Hoyt, C., Calcul, L., and Walstrom, K.M.C. (2025). elegans Cytoplasmic Isocitrate Dehydrogenase Neomorphic G98N and R133H Mutants Produce the Oncometabolite 2-Hydroxyglutarate. Int. J. Mol. Sci., 26.","DOI":"10.3390\/ijms26178238"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1084\/jem.20040342","article-title":"Masking of Phosphatidylserine Inhibits Apoptotic Cell Engulfment and Induces Autoantibody Production in Mice","volume":"200","author":"Asano","year":"2004","journal-title":"J. Exp. Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1625","DOI":"10.1016\/j.freeradbiomed.2007.02.026","article-title":"Nitric oxide, mitochondrial hyperpolarization, and T cell activation","volume":"42","author":"Nagy","year":"2007","journal-title":"Free Radic. Biol. Med."},{"key":"ref_10","doi-asserted-by":"crossref","unstructured":"Banki, K., and Perl, A. (Autoimmun. Rev., 2025). Cell type-specific regulation of the pentose phosphate pathway during development and metabolic stress-driven autoimmune diseases: Relevance for inflammatory liver, renal, endocrine, cardiovascular and neurobehavioral comorbidities, carcinogenesis, and aging, Autoimmun. Rev., accepted.","DOI":"10.1016\/j.autrev.2025.103781"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"2714","DOI":"10.1038\/s41467-020-16423-1","article-title":"Defective NADPH production in mitochondrial disease complex I causes inflammation and cell death","volume":"11","author":"Balsa","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"103273","DOI":"10.1016\/j.redox.2024.103273","article-title":"Malic enzymes in cancer: Regulatory mechanisms, functions, and therapeutic implications","volume":"75","author":"Wang","year":"2024","journal-title":"Redox Biol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1016\/j.freeradbiomed.2013.05.049","article-title":"A spontaneous mutation in the nicotinamide nucleotide transhydrogenase gene of C57BL\/6J mice results in mitochondrial redox abnormalities","volume":"63","author":"Ronchi","year":"2013","journal-title":"Free Radic. Biol. Med."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1038\/s42255-022-00711-9","article-title":"Cytosolic aldose metabolism contributes to progression from cirrhosis to hepatocarcinogenesis","volume":"5","author":"Oaks","year":"2023","journal-title":"Nat. Metab."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"1340","DOI":"10.1126\/science.1193494","article-title":"The Control of the Metabolic Switch in Cancers by Oncogenes and Tumor Suppressor Genes","volume":"330","author":"Levine","year":"2010","journal-title":"Science"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"927","DOI":"10.1089\/ars.2024.0694","article-title":"Mitochondrial Nicotinamide Nucleotide Transhydrogenase: Role in Energy Metabolism, Redox Homeostasis, and Cancer","volume":"41","author":"Gan","year":"2024","journal-title":"Antioxid. Redox Signal."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"241","DOI":"10.1016\/S0955-0674(03)00006-1","article-title":"Nicotinamide adenine dinucleotide, a metabolic regulator of transcription, longevity and disease","volume":"15","author":"Lin","year":"2003","journal-title":"Curr. Opin. Cell Biol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"609","DOI":"10.1042\/bj1150609a","article-title":"The redox state of free nicotinamide-adenine dinucleotide phosphate in the cytoplasm of rat liver","volume":"115","author":"Veech","year":"1969","journal-title":"Biochem. J."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"545","DOI":"10.1016\/j.cmet.2011.08.012","article-title":"Imaging Cytosolic NADH-NAD+ Redox State with a Genetically Encoded Fluorescent Biosensor","volume":"14","author":"Hung","year":"2011","journal-title":"Cell Metab."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1088","DOI":"10.1038\/nchembio.2454","article-title":"A genetically encoded tool for manipulation of NADP+\/NADPH in living cells","volume":"13","author":"Cracan","year":"2017","journal-title":"Nat. Chem. Biol."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2756","DOI":"10.1016\/S0021-9258(19)61730-8","article-title":"The Stability of Pyridine Nucleotides","volume":"236","author":"Lowry","year":"1961","journal-title":"J. Biol. Chem."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"e20115","DOI":"10.1002\/cppb.20115","article-title":"Adenine Nucleotide and Nicotinamide Adenine Dinucleotide Measurements in Plants","volume":"5","author":"Zhang","year":"2020","journal-title":"Curr. Protoc. Plant Biol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"367","DOI":"10.1016\/0003-2697(87)90506-9","article-title":"Spectrophotometric determination of oxidized and reduced pyridine nucleotides in erythrocytes using a single extraction procedure","volume":"164","author":"Zerez","year":"1987","journal-title":"Anal. Biochem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"32994","DOI":"10.1074\/jbc.271.51.32994","article-title":"Glutathione Levels and Sensitivity to Apoptosis Are Regulated by changes in Transaldolase expression","volume":"271","author":"Banki","year":"1996","journal-title":"J. Biol. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"123","DOI":"10.1042\/BJ20080722","article-title":"Transaldolase deficiency influences the pentose phosphate pathway, mitochondrial homoeostasis and apoptosis signal processing","volume":"415","author":"Qian","year":"2008","journal-title":"Biochem. J."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1546","DOI":"10.1172\/JCI35722","article-title":"Prevention of hepatocarcinogenesis and acetaminophen-induced liver failure in transaldolase-deficient mice by N-acetylcysteine","volume":"119","author":"Hanczko","year":"2009","journal-title":"J. Clin. Investig."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"14813","DOI":"10.1073\/pnas.0602678103","article-title":"Transaldolase is essential for maintenance of the mitochondrial transmembrane potential and fertility of spermatozoa","volume":"103","author":"Perl","year":"2006","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"167","DOI":"10.1089\/ars.2017.7014","article-title":"Extraction and Quantitation of Nicotinamide Adenine Dinucleotide Redox Cofactors","volume":"28","author":"Lu","year":"2017","journal-title":"Antioxid. Redox Signal."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"872","DOI":"10.1038\/nprot.2012.024","article-title":"A positive\/negative ion-switching, targeted mass spectrometry-based metabolomics platform for bodily fluids, cells, and fresh and fixed tissue","volume":"7","author":"Yuan","year":"2012","journal-title":"Nat. Prot."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"2847","DOI":"10.1016\/S0021-9258(17)42020-5","article-title":"Cloning and expression of the human gene for transaldolase: A novel highly repetitive element constitutes an integral part of the coding sequence","volume":"269","author":"Banki","year":"1994","journal-title":"J. Biol. Chem."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"e00291","DOI":"10.7554\/eLife.00291","article-title":"UNC93B1 mediates differential trafficking of endosomal TLRs","volume":"2","author":"Lee","year":"2013","journal-title":"Elife Sci."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"954","DOI":"10.1126\/science.1852076","article-title":"Cloning of a Factor Required for Activity of the Ah (Dioxin) Receptor","volume":"252","author":"Hoffman","year":"1991","journal-title":"Science"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"675","DOI":"10.1007\/s00125-005-1680-z","article-title":"A genetic and physiological study of impaired glucose homeostasis control in C57BL\/6J mice","volume":"48","author":"Toye","year":"2005","journal-title":"Diabetologia"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"2153","DOI":"10.2337\/db06-0358","article-title":"Deletion of Nicotinamide Nucleotide Transhydrogenase: A New Quantitive Trait Locus Accounting for Glucose Intolerance in C57BL\/6J Mice","volume":"55","author":"Freeman","year":"2006","journal-title":"Diabetes"},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Williams, J.L., Hall, C.L., Meimaridou, E., and Metherell, L.A. (2021). Loss of nnt increases expression of oxidative phosphorylation complexes in c57bl\/6j hearts. Int. J. Mol. Sci., 22.","DOI":"10.3390\/ijms22116101"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"98","DOI":"10.1159\/000486337","article-title":"Absence of Nicotinamide Nucleotide Transhydrogenase in C57BL\/6J Mice Exacerbates Experimental Atherosclerosis","volume":"55","author":"Vozenilek","year":"2018","journal-title":"J. Vasc. Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"e201900593","DOI":"10.26508\/lsa.201900593","article-title":"Mylk3 null c57bl\/6n mice develop cardiomyopathy, whereas nnt null c57bl\/6j mice do not","volume":"3","author":"Williams","year":"2020","journal-title":"Life Sci. Alliance"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"210","DOI":"10.1016\/j.neuroscience.2020.05.042","article-title":"Mitochondrial NAD(P)+ Transhydrogenase is Unevenly Distributed in Different Brain Regions, and its Loss Causes Depressive-like Behavior and Motor Dysfunction in Mice","volume":"440","author":"Francisco","year":"2020","journal-title":"Neuroscience"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"721","DOI":"10.1016\/j.bbabio.2006.03.010","article-title":"Mitochondrial NADPH, transhydrogenase and disease","volume":"1757","author":"Rydstrom","year":"2006","journal-title":"Biochim. Biophys. Acta"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"R82","DOI":"10.1186\/gb-2013-14-7-r82","article-title":"A comparative phenotypic and genomic analysis of C57BL\/6J and C57BL\/6N mouse strains","volume":"14","author":"Simon","year":"2013","journal-title":"Genome Biol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"534","DOI":"10.1007\/s00335-010-9299-x","article-title":"Genetic modifier of mitochondrial superoxide dismutase-deficient mice delays heart failure and prolongs survival","volume":"21","author":"Kim","year":"2010","journal-title":"Mamm. Genome"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1016\/j.cmet.2015.07.008","article-title":"Reversal of Mitochondrial Transhydrogenase Causes Oxidative Stress in Heart Failure","volume":"22","author":"Nickel","year":"2015","journal-title":"Cell Metab."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1187","DOI":"10.1093\/hmg\/ddl034","article-title":"Genetic modifiers of the phenotype of mice deficient in mitochondrial superoxide dismutase","volume":"15","author":"Huang","year":"2006","journal-title":"Hum. Mol. Genet."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"4834","DOI":"10.1093\/nar\/gkq249","article-title":"NUDT16 is a (deoxy)inosine diphosphatase, and its deficiency induces accumulation of single-strand breaks in nuclear DNA and growth arrest","volume":"38","author":"Iyama","year":"2010","journal-title":"Nucl. Acids Res."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1111\/j.1476-5381.2012.02110.x","article-title":"The autophagic inhibitor 3-methyladenine potently stimulates PKA-dependent lipolysis in adipocytes","volume":"168","author":"Heckmann","year":"2013","journal-title":"Brit. J. Pharmacol."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"324","DOI":"10.1186\/s12967-025-06341-5","article-title":"Comprehensive review of the expanding roles of the carnitine pool in metabolic physiology: Beyond fatty acid oxidation","volume":"23","author":"Xiang","year":"2025","journal-title":"J. Transl. Med."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"499","DOI":"10.1038\/cdd.2014.219","article-title":"Phosphatidylethanolamine positively regulates autophagy and longevity","volume":"22","author":"Rockenfeller","year":"2015","journal-title":"Cell Death Differ."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/S0161-813X(03)00099-8","article-title":"Dopamine-Derived Salsolinol Derivatives as Endogenous Monoamine Oxidase Inhibitors: Occurrence, Metabolism and Function in Human Brains","volume":"25","author":"Naoi","year":"2004","journal-title":"NeuroToxicology"},{"key":"ref_49","doi-asserted-by":"crossref","unstructured":"Sanayama, H., Ito, K., Ookawara, S., Uemura, T., Sakiyama, Y., Sugawara, H., Tabei, K., Igarashi, K., and Soda, K. (2023). Whole Blood Spermine\/Spermidine Ratio as a New Indicator of Sarcopenia Status in Older Adults. Biomedicines, 11.","DOI":"10.3390\/biomedicines11051403"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"3243","DOI":"10.1038\/s41467-020-17067-x","article-title":"Spermine synthase and MYC cooperate to maintain colorectal cancer cell survival by repressing Bim expression","volume":"11","author":"Guo","year":"2020","journal-title":"Nat. Commun."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1428","DOI":"10.1038\/nm.4222","article-title":"Cardioprotection and lifespan extension by the natural polyamine spermidine","volume":"22","author":"Eisenberg","year":"2016","journal-title":"Nat. Med."},{"key":"ref_52","doi-asserted-by":"crossref","unstructured":"Hestad, K., Alexander, J., Rootwelt, H., and Aaseth, J.O. (2022). The Role of Tryptophan Dysmetabolism and Quinolinic Acid in Depressive and Neurodegenerative Diseases. Biomolecules, 12.","DOI":"10.3390\/biom12070998"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"986","DOI":"10.1161\/ATVBAHA.110.207449","article-title":"Prostaglandins and Inflammation","volume":"31","author":"Ricciotti","year":"2011","journal-title":"Arterioscler. Thromb. Vasc. Biol."},{"key":"ref_54","doi-asserted-by":"crossref","unstructured":"Womack, T.R., Vollert, C.T., Ohia-Nwoko, O., Schmitt, M., Montazari, S., Beckett, T.L., Mayerich, D., Murphy, M.P., and Eriksen, J.L. (2022). Prostacyclin Promotes Degenerative Pathology in a Model of Alzheimer\u2019s Disease. Front. Cell. Neurosci., 16.","DOI":"10.3389\/fncel.2022.769347"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"2598","DOI":"10.1038\/s41467-024-46441-2","article-title":"Rab4A-directed endosome traffic shapes pro-inflammatory mitochondrial metabolism in T cells via mitophagy, CD98 expression, and kynurenine-sensitive mTOR activation","volume":"15","author":"Huang","year":"2024","journal-title":"Nat. Commun."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"1247","DOI":"10.3892\/ol.2012.931","article-title":"Redox status expressed as GSH:GSSG ratio as a marker for oxidative stress in paediatric tumour patients","volume":"4","author":"Zitka","year":"2012","journal-title":"Oncol. Lett."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1038\/nature11066","article-title":"AMPK regulates NADPH homeostasis to promote tumour cell survival during energy stress","volume":"485","author":"Jeon","year":"2012","journal-title":"Nature"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"2921","DOI":"10.1172\/JCI66353","article-title":"Transcription factor NRF2 regulates miR-1 and miR-206 to drive tumorigenesis","volume":"123","author":"Singh","year":"2013","journal-title":"J. Clin. Investig."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.freeradbiomed.2017.07.018","article-title":"Control of the NADPH supply for oxidative stress handling in cancer cells","volume":"112","author":"Saavedra","year":"2017","journal-title":"Free Radic. Biol. Med."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1016\/0065-2571(74)90025-9","article-title":"The regulation of the pentose phosphate cycle in rat liver","volume":"12","author":"Krebs","year":"1974","journal-title":"Adv. Enzym. Regul."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"12846","DOI":"10.1038\/srep12846","article-title":"Determination of the Cytosolic NADPH\/NADP Ratio in Saccharomyces cerevisiae using Shikimate Dehydrogenase as Sensor Reaction","volume":"5","author":"Zhang","year":"2015","journal-title":"Sci. Rep."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1016\/S0378-4347(00)80293-5","article-title":"Determination of pyridine dinucleotides in cell extracts by high-performance liquid chromatography","volume":"225","author":"Jones","year":"1981","journal-title":"J. Chromatog. B Biomed. Sci. Appl."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.ab.2015.01.003","article-title":"Extraction parameters for metabolomics from cultured cells","volume":"475","author":"Ser","year":"2015","journal-title":"Anal. Biochem."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1146\/annurev-biochem-061516-044952","article-title":"Metabolite measurement: Pitfalls to avoid and practices to follow","volume":"86","author":"Lu","year":"2017","journal-title":"Ann. Rev. Biochem."},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"743","DOI":"10.1021\/ac051312t","article-title":"Solvent-dependent metabolite distribution, clustering, and protein extraction for serum profiling with mass spectrometry","volume":"78","author":"Want","year":"2006","journal-title":"Anal. Chem."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1186\/s11658-023-00452-x","article-title":"Comparison between 5 extractions methods in either plasma or serum to determine the optimal extraction and matrix combination for human metabolomics","volume":"28","author":"Lepoittevin","year":"2023","journal-title":"Cell. Mol. Biol. Lett."},{"key":"ref_67","doi-asserted-by":"crossref","unstructured":"Perl, A. (2012). Assessment of mitochondrial dysfunction in lymphocytes of patients with systemic lupus erythematosus. Autoimmunity: Methods and Protocols, Springer.","DOI":"10.1007\/978-1-60761-720-4_4"},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1530\/JOE-16-0638","article-title":"NNT is a key regulator of adrenal redox homeostasis and steroidogenesis in male mice","volume":"236","author":"Meimaridou","year":"2018","journal-title":"J. Endocrinol."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"2803","DOI":"10.1007\/s00216-010-4111-z","article-title":"Structure elucidation of the thermal degradation products of the nucleotide cofactors NADH and NADPH by nano-ESI-FTICR-MS and HPLC-MS","volume":"398","author":"Hofmann","year":"2010","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"57","DOI":"10.1007\/s11120-021-00835-1","article-title":"Quantification of NAD(P)H in cyanobacterial cells by a phenol extraction method","volume":"148","author":"Tanaka","year":"2021","journal-title":"Photosynth. Res."},{"key":"ref_71","first-page":"209","article-title":"Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries","volume":"71","author":"Sung","year":"2021","journal-title":"CA Cancer J. Clin."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1186\/s41256-025-00416-y","article-title":"The spatio-temporal trends and determinants of liver cancer attributable to specific etiologies: A systematic analysis from the Global Burden of Disease Study 2021","volume":"10","author":"Liu","year":"2025","journal-title":"Glob. Health Res. Policy"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"799","DOI":"10.1080\/1744666X.2017.1327352","article-title":"Epidemiology of systemic lupus erythematosus","volume":"13","author":"Alarcon","year":"2017","journal-title":"Exp. Rev. Clin. Immunol."},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1136\/ard-2022-223035","article-title":"Global epidemiology of systemic lupus erythematosus: A comprehensive systematic analysis and modelling study","volume":"82","author":"Tian","year":"2023","journal-title":"Ann. Rheum. Dis."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"2532860","DOI":"10.1080\/07853890.2025.2532860","article-title":"Musculoskeletal disorders in women of childbearing age: Global trends, socio-demographic disparities, and future projections","volume":"57","author":"Luo","year":"2025","journal-title":"Ann. Med."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"2881","DOI":"10.1093\/hmg\/ddi320","article-title":"Fc\u03b3RIIB Ile232Thr transmembrane polymorphism associated with human systemic lupus erythematosus decreases affinity to lipid rafts and attenuates inhibitory effects on B cell receptor signaling","volume":"14","author":"Kono","year":"2005","journal-title":"Hum. Mol. Genet."},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"33562","DOI":"10.1074\/jbc.M704442200","article-title":"NAD Kinase Levels Control the NADPH Concentration in Human Cells","volume":"282","author":"Pollak","year":"2007","journal-title":"J. Biol. Chem."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"L36","DOI":"10.1152\/ajplung.00283.2001","article-title":"Intracellular redox status affects transplasma membrane electron transport in pulmonary arterial endothelial cells","volume":"282","author":"Merker","year":"2002","journal-title":"Am. J. Physiol. Lung Cell. Mol. Physiol."},{"key":"ref_79","doi-asserted-by":"crossref","unstructured":"Brookes, P.S., Shiva, S., Patel, R.P., and Darley-Usmar, V.M. (2002). Measurement of mitochondrial respiratory thresholds and the control of respiration by nitric oxide. Methods in Enzymology Nitric Oxide, Part D: Oxide Detection, Mitochondria and Cell Functions, and Peroxynitrite Reactions, Academic Press.","DOI":"10.1016\/S0076-6879(02)59194-1"},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"248","DOI":"10.1016\/0003-2697(76)90527-3","article-title":"A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding","volume":"72","author":"Bradford","year":"1976","journal-title":"Anal. Biochem."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"280","DOI":"10.1007\/s11306-012-0482-9","article-title":"Translational biomarker discovery in clinical metabolomics: An introductory tutorial","volume":"9","author":"Xia","year":"2013","journal-title":"Metabolomics"},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"W127","DOI":"10.1093\/nar\/gks374","article-title":"MetaboAnalyst 2.0-a comprehensive server for metabolomic data analysis","volume":"40","author":"Xia","year":"2012","journal-title":"Nucl. Acids Res."}],"container-title":["International Journal of Molecular Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/21\/10371\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T05:34:31Z","timestamp":1761629671000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1422-0067\/26\/21\/10371"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,24]]},"references-count":82,"journal-issue":{"issue":"21","published-online":{"date-parts":[[2025,11]]}},"alternative-id":["ijms262110371"],"URL":"https:\/\/doi.org\/10.3390\/ijms262110371","relation":{},"ISSN":["1422-0067"],"issn-type":[{"value":"1422-0067","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,24]]}}}