Tryptophan–NAD+ pathway metabolites as putative biomarkers and predictors of peroxisome proliferation

Delaney, Jane, Hodson, Mark P., Thakkar, Hansa, Connor, Susan C., Sweatman, Brian C., Kenny, Steve P., McGill, Paul J., Holder, Julie C., Hutton, Kathryn A., Haselden, John N. and Waterfield, Catherine J. (2005) Tryptophan–NAD+ pathway metabolites as putative biomarkers and predictors of peroxisome proliferation. Archives of Toxicology, 79 4: 208-223. doi:10.1007/s00204-004-0625-5

Author Delaney, Jane
Hodson, Mark P.
Thakkar, Hansa
Connor, Susan C.
Sweatman, Brian C.
Kenny, Steve P.
McGill, Paul J.
Holder, Julie C.
Hutton, Kathryn A.
Haselden, John N.
Waterfield, Catherine J.
Title Tryptophan–NAD+ pathway metabolites as putative biomarkers and predictors of peroxisome proliferation
Journal name Archives of Toxicology   Check publisher's open access policy
ISSN 0340-5761
Publication date 2005-04-01
Year available 2005
Sub-type Article (original research)
DOI 10.1007/s00204-004-0625-5
Open Access Status Not Open Access
Volume 79
Issue 4
Start page 208
End page 223
Total pages 16
Place of publication Germany
Publisher Springer
Language eng
Formatted abstract
The present study was designed to provide further information about the relevance of raised urinary levels of N-methylnicotinamide (NMN), and/or its metabolites N-methyl-4-pyridone-3-carboxamide (4PY) and N-methyl-2-pyridone-3- carboxamide (2PY), to peroxisome proliferation by dosing rats with known peroxisome proliferator-activated receptor α (PPARα) ligands [fenofibrate, diethylhexylphthalate (DEHP) and long-chain fatty acids (LCFA)] and other compounds believed to modulate lipid metabolism via PPARα-independent mechanisms (simvastatin, hydrazine and chlorpromazine). Urinary NMN was correlated with standard markers of peroxisome proliferation and serum lipid parameters with the aim of establishing whether urinary NMN could be used as a biomarker for peroxisome proliferation in the rat. Data from this study were also used to validate a previously constructed multivariate statistical model of peroxisome proliferation (PP) in the rat. The predictive model, based on 1H nuclear magnetic resonance (NMR) spectroscopy of urine, uses spectral patterns of NMN, 4PY and other endogenous metabolites to predict hepatocellular peroxisome count. Each treatment induced pharmacological (serum lipid) effects characteristic of their class, but only fenofibrate, DEHP and simvastatin increased peroxisome number and raised urinary NMN, 2PY and 4PY, with simvastatin having only a transient effect on the latter. These compounds also reduced mRNA expression for aminocarboxymuconate-semialdehyde decarboxylase (ACMSDase, EC, the enzyme believed to be involved in modulating the flux of tryptophan through this pathway, with decreasing order of potency, fenofibrate (-10.39-fold) >DEHP (-3.09-fold) >simvastatin (-1.84-fold). Of the other treatments, only LCFA influenced mRNA expression of ACMSDase (-3.62-fold reduction) and quinolinate phosphoribosyltransferase (QAPRTase, EC (-2.42-fold) without any change in urinary NMN excretion. Although there were no correlations between urinary NMN concentration and serum lipid parameters, NMN did correlate with peroxisome count (r 2=0.63) and acyl-CoA oxidase activity (r 2=0.61). These correlations were biased by the large response to fenofibrate compared to the other treatments; nevertheless the data do indicate a relationship between the tryptophan-NAD + pathway and PPARα-dependent pathways, making this metabolite a potentially useful biomarker to detect PP. In order to strengthen the observed link between the metabolites associated with the tryptophan-NAD+ pathway and more accurately predict PP, other urinary metabolites were included in a predictive statistical model. This statistical model was found to predict the observed PP in 26/27 instances using a pre-determined threshold of 2-fold mean control peroxisome count. The model also predicted a time-dependent increase in peroxisome count for the fenofibrate group, which is important when considering the use of such modelling to predict the onset and progression of PP prior to its observation in samples taken at autopsy. © Springer-Verlag 2004.
Keyword Biomarkers
Multivariate data analysis
Peroxisome proliferation
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: Australian Institute for Bioengineering and Nanotechnology Publications
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Citation counts: TR Web of Science Citation Count  Cited 33 times in Thomson Reuters Web of Science Article | Citations
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Created: Sat, 04 Jun 2011, 00:19:51 EST by Dr Mark Hodson on behalf of Aust Institute for Bioengineering & Nanotechnology