Compact, Real-Time Analyzer for C-13 and O-18 Isotope Ratios of Carbon Dioxide in Breath Air

Oxygen-18 and carbon-13 isotopes in eCO2 and erythrocytes carbonic anhydrase activity of Finnish prediabetic population

“…The latest research lines in the field of isotopeselective breath testing include early sepsis and infection detection [7,[10][11][12] and prediabetes (PD) and type 2 diabetes (T2D) screening [8]. These applications are based on monitoring the breath delta values (BDVs, ‰) of 18 O/ 16 O and/or 13 C/ 12 C in eCO 2 (i.e. δ 18 O and δ 13 C) and rely on the natural fluctuation in the isotope ratios during innate or induced metabolic events [2,9,11]; thus, no labeling is used.…”

“…shift in BDV in relation to the baseline, are utilized in diagnostic purposes. BDVs of 18 O/ 16 O and 13 C/ 12 C are often calculated in relation to an international Vienna Pee Dee Belminite (VPDB) standard. DOB values (i.e.…”

“…Based on the recent studies by Ghosh et al [8], monitoring of 18 O/ 16 O isotope ratios during the 2 h oral glucose tolerance test (2 h OGTT) provides a potential non-invasive method for the assessment of glycated hemoglobin (HbA1c) and insulin sensitivity in Indian participants with PD and T2D. Furthermore, they proposed that 18 O/ 16 O fractionation patterns reflect carbonic anhydrase (CA) activity in PD individuals and T2D patients: fasting CA activity was shown to be reduced in T2D patients in comparison to PD and non-diabetic controls (NDCs), and this phenomenon was suggested to be related to the increased glycosylation of CA in T2D patients [8]. CA enzymes, divided into 7 subgroups and comprising 15 isoforms, are present in various human tissues, and catalyze the conversion of CO 2 to bicarbonate (HCO 3 −) in blood and tissues, thus participating in the pH regulation of the human body [14].…”

“…CA enzymes, divided into 7 subgroups and comprising 15 isoforms, are present in various human tissues, and catalyze the conversion of CO 2 to bicarbonate (HCO 3 −) in blood and tissues, thus participating in the pH regulation of the human body [14]. Ghosh et al [8] suggested that while CA also induces the efficient exchange of oxygen isotopes between blood plasma H 2 18 O and 12 C 16 O 2 during respiration, higher CA activity results in a higher 18 O/ 16 O ratio in exhaled breath. That is, a change in CA activity can be seen as a shift in δ 18 O in eCO 2 , reflecting the 18 O/ 16 O ratio in body H 2 O and CO 2 .…”

“…Ghosh et al [8] suggested that while CA also induces the efficient exchange of oxygen isotopes between blood plasma H 2 18 O and 12 C 16 O 2 during respiration, higher CA activity results in a higher 18 O/ 16 O ratio in exhaled breath. That is, a change in CA activity can be seen as a shift in δ 18 O in eCO 2 , reflecting the 18 O/ 16 O ratio in body H 2 O and CO 2 . Changes in CA activity seem to be involved in the altered metabolism in different stages of T2D [15], and thus, isotopic enrichment of 18 O in eCO 2 could be observed in PD individuals and T2D patients [8].…”