Pradeep Kumar1, Rajeev Kumar 2, Sanjay Sharma3, Sanjay Thulkar4, S. Datta Gupta5, S. senthil Kumaran1, Rama Jayasundar1, N. R. Jagannathan6, and Virendra Kumar1
1Department of NMR, All India Institute of Medical Sciences, New Delhi, India, Ansari nagar, India, 2Department of Urology, All India Institute of Medical Sciences, New Delhi, India, Ansari nagar, India, 3Department of Radio-diagnosis, RPC, All India Institute of Medical Sciences, New Delhi, India, Ansari nagar, India, 4Department of Radio-diagnosis, IRCH, All India Institute of Medical Sciences, New Delhi, India, Ansari nagar, India, 5Department of Pathology, All India Institute of Medical Sciences, New Delhi, India, Ansari nagar, India, 6Present address: Department of Radiology, Chettinad Academy of Research and Education, Kelambakkam, Tamil Nadu, India
Synopsis
In
the present study we reported the effect of dietary lifestyle on metabolic
profile of blood plasma in prostate cancer (PCa) patients using NMR spectroscopy
the long term effects of dietary patterns our metabolic profiles and PCa have
been reported in literatures. A
significantly higher concentration of choline, glutamate, creatine, succinate, 1-methylhistidine
and methionine were observed in non-vegetarians patients compared to vegetarians.
Our results suggested that the metabolic pathway alterations seen
in amino acids, phospholipids and energy may be related to changes due diet to
and PCa progression.
INTRODUCTION
Prostate cancer (PCa) is most frequently
diagnosed malignancy in men over the age of 50 years worldwide. It
is a slow growing cancer with absence of symptoms at early stages. The pathogenesis of PCa has not been
completely understood including the major risk factors associated to cancer
development like age, race and family history. Also life style, diet and
environmental factors can induce genetic modifications and initiate
tumorigenesis processes. Diet is one of the key environmental factors affecting the incidence of
various chronic health disorders. Nonveg diet intake has
been associated with an elevated risk of several chronic diseases, including
diabetes, heart disease and cancers of the colorectal, stomach, esophagus,
prostate, breast, and pancreas as well
as all-cause mortality1-3. Thus, the present study was carried out to investigate
differences in blood plasma of PCa patients and identify biomarker/s associated
to the dietary habits of vegetarians and non-vegetarians.METHODS
Blood
samples were collected from PCa patients with non-vegetarian (n=43) and from
vegetarian (n=25) in morning pre-prandial after overnight fasting. Clinical
characteristics of the two groups are presented in Table 1. An informed consent
was taken and the study was approved by Institute Ethics Committee. Proton
spectra of blood plasma samples were acquired at 700 MHz spectrometer (Agilent,
USA) using 1D CPMG with pre-saturation. The following parameters were used for
1D NMR: 64 scan, with a 70s relaxation delay and a spectral width of 9124.1 Hz
with an echo time of 15ms. Two dimensional (2D) TOCSY experiment was carried
out for assignments of metabolite peaks. For comparison between these two
patient groups, unpaired Mann-Whitney U test was carried out using SPSS
software. A p-value <0.05 was considered significant. Univariate (receiver
operating characteristics (ROC) curve analysis) and multivariate (orthogonal
partial least squares–discriminant analyses (OPLS-DA), variable importance to
projection (VIP) score statistical analysis was carried out using MetaboAnalyst
4.0.RESULTS
Figure
1 shows the representative aliphatic region of 1D 1H NMR spectrum of
blood plasma sample of a PCa patient with non-vegetarian (A) and a vegetarian
(B). In all, 29 metabolites were assigned using 1D and 2D NMR. A metabolomics
analysis of blood plasma showed an increase
concentration of 5 metabolites, glutamate
(Glu), creatine (Cr), choline (Cho), succinate (Suc), 1-methyl histidine(1-MH)
and lower concentration of methionine
(Met) in non-vegetarian PCa patients with as compared to vegetarian. For the
concentration [μM (Mean (SD)] of 6 metabolites that showed significant (p<0.05)
differences, the AUC values and VIP scores (>1) between the two groups were determined
and presented in Table 2. Figure 2 shows the OPLS -DA score plot showing the discrimination of non-vegetarian
PCa
patients from vegetarian.DISCUSSION
Our
data revealed a significantly higher concentration of Cho in the blood plasma
of non-vegetarian PCa patients compared to vegetarian. Foods
such as meat, meat products, egg yolks and high-fat dairy products are high in
phosphatidylcholine and Cho4. Glucogenic amino acid such as Glu was
elevated in PCa patients with non-vegetarian diet. Cr
is a muscle breakdown product and previous studies have reported higher Cr
levels in individuals who consume a non-vegetarian diet (meat)5. Our
result also showed significantly higher concentration of 1-methylhistidine with
increasing non-veg diets (mainly red meat consumption)4. In
contrast, fish eaters had the highest concentrations of amino acids (such as
leucine and methionine)6. The ROC curve analysis results indicated
that in blood plasma, 3 metabolites with high AUC of above 0.650 (Cr, Met and
Suc) while 3 metabolites with less than 0.650 AUC values were seen (such as
Glu, Cho and 1-HM). Those metabolites with VIP
score (>1.0) were considered potential biomarker/s to discriminate between non-vegetarian
patients and vegetarian. MetaboAnalyst 4.0 was used to identify the
metabolic pathways which could have been altered in non-vegetarians versus
vegetarians. The seven unique significantly altered metabolic pathways seen
were arginine and proline metabolism, glycerophosphocholine metabolism,
glycine, serine and threonine metabolism, citrate cycle, histidine metabolism,
glutamate and glutamine metabolism, and cysteine and methionine metabolism.CONCLUSION
This
preliminary
study demonstrated that NMR based metabolomics may be useful for distinguishing
non-vegetarian PCa patients and vegetarian dietary lifestyle. Further our results provided a better
understanding of the metabolic pathway alterations through changes in amino
acids, phospholipids, and energy may be associated with diets and PCa progression.Acknowledgements
NRJ thanks SERB, Government of India funding under J.C. Bose Fellowship. PK acknowledges UGC fellowship.
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