Measurement of 1,5-anhydroglucitol in blood and saliva: from non-targeted metabolomics to biochemical assay

Abstract

BackgroundDiabetes testing using saliva, rather than blood and urine, could facilitate diabetes screening in public spaces. We previously identified 1,5-anhydro-d-glucitol (1,5-AG) in saliva as a diabetes biomarker. The Glycomark™ assay kit is FDA approved for 1,5-AG measurement in blood. Here we evaluated its applicability for 1,5-AG quantification in saliva.MethodsUsing pooled saliva samples, we validated Glycomark™ assay use with a RX Daytona+ clinical chemistry analyser. We then used this set-up to analyse 82 paired blood and saliva samples from a diabetes case–control study, for which broad mass spectrometry-based characterization of the blood and saliva metabolome was also available. Osmolality was measured to account for potential variability in saliva samples.ResultsThe technical variability of the read-outs for the pooled saliva samples (CV = 2.05 %) was comparable to that obtained with manufacturer-provided blood surrogate quality controls (CV = 1.38–1.8 %). We found a high correlation between Glycomark assay and mass spectrometry measurements of serum 1,5-AG (r2 = 0.902), showing reproducibility of the non-targeted metabolomics results. The significant correlation between the osmolality measurements performed at two independent platforms with the time interval of 2 years (r2 = 0.887), also indicates the sample integrity. The assay read-out for saliva was not correlated with the mass spectrometry-based 1,5-AG saliva measurements. Comparison with the full saliva metabolome revealed a high correlation of the saliva assay read-outs with galactose.ConclusionsGlycomark™ assay read-outs for saliva were stable and replicable. However, the signal was dominated by galactose, which is biochemically similar to 1,5-AG and absent in blood. Adapting the 1,5-AG kit for saliva analysis will require enzymatic depletion of galactose. This should be feasible, since the assay already includes a similar step for glucose depletion from blood samples.

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“…Hence, identification of treating agents of ALS and other neurological disorders in Ber fruit is a novel finding of this work, which may lead to pharmaceutical use of Ber fruit as a good source of treating agent of fatal diseases like ALS. Besides above, Zizuphus fruits are hereby reported as good source of Thymine, flavouring agents (Maltol, Pentanoic acid, Nonyl ester) 24,28 , surfactants (2-Hexadecanoic acid), indicator of Hepatic Carnitine Palmitoyl Transferase I deficiency (Malonic acid, ethyl 4) 29 , agents used in perfumery and manufacture of dyes (Formic acid), diabetes marker (Compound; 1, 5 Anhydroglucitrol) 36 , total cholesterol regulator (Compound; Stigmasterol) 42 and plasticizer (Compound; Nonanoic acid) 34 .…”

“…27 , bacteriostatic, fungicide (3, 4-Altrosan) activity 34 . Moreover, compounds known as carbohydrate metabolism regulator, diabetes marker (1, 5-Anhydroglucitrol, Polygalitol) 36 , immunosuppressant, neuroprotective against retinal ischemia (D-Allose) were also reported 30, 31, 32, 33, . Surprisingly, Molinate and Levetiracetam compounds known to have anti-spermatogenic and anti-epileptic potential 21,23 were also identified in MEZM fruit.…”

Metabolic profiling of pre-gestational and gestational diabetes mellitus identifies novel predictors of pre-term delivery

“…Metabolic signature of GDM, T2DM and DM (GDM + T2DM): In recent years, metabolomics has been widely used in the identification of novel pathways and specific biomarkers for insulin resistance and T2DM [ 22 , 30 – 32 ]. The data presented here offers a holistic view of the changes in plasma metabolites in relation to GDM and T2DM in pregnant women in their second trimester compared to BMI and GA-matched controls.…”

A Review of Analytical Techniques and Their Application in Disease Diagnosis in Breathomics and Salivaomics Research

“…Most studies measure each sample in duplicate or triplicate for each analyte, with some researchers extending beyond this and analyzing each sample up to 10 times (more in some cases) [ 26 ]. For saliva and breath condensate, pooled samples are typically used as a quality control measure [ 27 , 28 ]. Such a protocol ensures that both sample variation and analytical drift are captured and corrected, ensuring that the analyzed breath and saliva samples are scientifically valid.…”