Virendra Kumar1, Naveen Kumar MS2, sujeet kumar mewar1, Pradeep Kumar1, Naveet Wig2, Prayas Sethi2, and Sanjeev Sinha2
1Department of NMR, All India Institute of Medical Sciences, New Delhi, India, 2Department of Medicine, All India Institute of Medical Sciences, New Delhi, India
Synopsis
The present study reported the differences in metabolic profile of serum
samples from patient with sepsis to identify survivor and non-survivor (day 0) using
NMR metabolomics. A significantly higher concentration of
tyrosine, histidine, methionine, betaine, creatine, phosphocreatine and choline
in the serum of sepsis patients who did not survive septic shock compared to
survivors. These findings suggest that metabolic alterations at day 0 may
predict the survival of the septic patients.
Introduction
Sepsis is a life-threatening organ dysfunction
caused by a deregulated host response to infection. Septic shock is a subset of
sepsis with underlying circulatory cellular and metabolic abnormalities associated
with higher mortality rates1-2. Early supportive therapy with fluid
resuscitation and vasopressors to restore hemodynamics and reduce tissue hypo-perfusion
is decisive for the patient’s outcome and has figured in treatment guidelines
for decades. However, mortality rates for septic shock may reach about 60% even
with early treatment and poor prognosis mainly related to multi-organ
dysfunction or MOF3. One of the most accepted organic dysfunction
scores in sepsis management is the Sequential Organ Failure Assessment score (SOFA)4.
The present study was carried to investigate the metabolic profile of serum
sample of sepsis patients who were survivor at day 7.Methods
Sepsis Patients
admitted in Medicine ICU with proven sepsis were included in the study. Blood sample collected from sepsis patients at
0 day. Sepsis patients survival was taken at day 7. Proton spectra of serum
samples were carried out at 700 MHz spectrometer (Agilent, USA). One
dimensional 1D CPMG with water pre-saturation was acquired at 25°C with
following parameters: spectral width: 9124.1 Hz; scans: 64; relaxation delays: 70s. Two dimensional (2D) total correlation
spectroscopy (TOCSY) experiments were carried out for assignments of resonances.
The data was processed using the Vnmrj 2.3A software (Agilent technologies). For comparison between two groups, unpaired Mann–Whitney
U test was used. A p-value < 0.05 was considered significant. Statistical
analysis was carried out using SPSS software (SPSS Inc. Chicago, IL, USA) and
MetaboAnalyst4.0. In order to analyze the data obtained in the performed
studies, the univariate (receiver operating characteristics (ROC) curve
analysis) and multivariate (orthogonal partial least squares–discriminant
analysis (OPLS-DA), variable importance to projection (VIP) score, statistical
analyses were applied in serum samples of non-survivor and survivor sepsis
patients.Results
In
all, 30 metabolite were assigned using 1D and 2D NMR. Figure 1 shows the
representative aliphatic region of 1D proton NMR
spectrum of serum sample of a sepsis patient
day 0 non- survivor (A) and a sepsis patient day 0 survivor (B). The concentration [mM (mean (range)] of 7 metabolites that
showed significant (p< 0.05) difference, AUC values and VIP score (>1) between
sepsis patient non- survivor and sepsis patient survivor is presented in Table
1. A significantly higher concentration of tyrosine (Tyr), histidine (His),
methionine (Met), betaine, creatine (Cr), phosphocreatine (PCr) and Choline
(Cho) in the serum of non-survivor sepsis patients compared to survivor sepsis
patients. Figure
2 shows the OPLS -DA score plot clearly discriminating non-survivor from
survivor sepsis patients.Discussion
The present study revealed significantly higher
concentration of aromatic amino acids like Tyr, His and other amino acid likes
Met in serum sample of non-survivor sepsis patients compared to survivor patients.
This may be due to mitochondrial dysfunction, altered tricarboxlylic acid or TCA
cycle5, which results in dampened aerobic respiration as well abnormal
energy supply. Severe disorders in energy supply should be an import factor inducing
organ failure6. Furthermore, a significantly higher concentration of
Cr and PCr in non-survivor patients was seen compared to survivor patients
may be due to altered energy related
metabolism6. Cho is a
precursor of betaine, the increased concentration of both betaine and Cho in serum
of non-survivor and survivors sepsis patients. Cho and betaine also have involvement
in pro-inflammatory cytokines
induce inflammation and amplify oxidative stress by stimulating the production
of reactive oxygen and nitrogen species7. The
univariate ROC curve analyses indicated that in serum, the metabolites such as
PCr and Cr showed an AUC with high value (0.953 and 0.877, respectively). Those
metabolites with VIP score (>1.0) were considered potential biomarker/s to
discriminate between non-survivor sepsis patients and survivor at day 0. Figure 2 shows a PLS-DA classification score
plot that depicts the differentiation of non-survivors and survivor sepsis
patients in separate quadrant.Conclusion
The
significant difference in metabolite concentration of amino acids, lipid and
energy may be a used as a measure to discriminate between non-survivors and survivors sepsis
patients
at day 0. Our findings indicate that metabolite alterations are
associated with progression of the disease.Acknowledgements
No acknowledgement found.References
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