Modifications and oxidation of lipids and proteins in human serum detected by thermochemiluminescence

Abstract

Detection of electronically excited species (EES) in body fluids may constitute an important diagnostic tool in various pathologies. Examples of such products are triplet excited carbonyls (TEC), which can be a source for photon emission in the 400-550 nm range. The aim of the present study was to determine the actual contribution of lipid and protein components (protein carbonyls) to photon emission generated by thermochemiluminescence (TCL) during the heating of biological fluids. In this study, a new TCL Photometer device, designed by Lumitest Ltd, Israel, was used. Samples were heated to a constant temperature of 80 +/- 0.5 degrees C for 280 s and photon emission was measured at several time points. In order to compare the results of TCL measurements to conventional methods of detecting lipid and protein oxidation, each examined sample was also heated in a waterbath at 80 degrees C for 10-280 s. Lipid and protein oxidation were subsequently measured using conventional methods. The TCL of four polyunsaturated fatty acids (PUFA) with three to six double bonds was measured. The elevation of the PUFA TCL amplitude correlated with the increase in the number of double bonds of PUFA. A correlation between the increase in TCL intensity and protein carbonyl generation in bovine serum albumin (BSA) was also observed. In the venous blood serum, our study showed that an increase of TCL intensity during heating reflected the cleavage of TEC of lipid origin. Our study suggests that biological molecules such as proteins, lipids and other molecules, which may become unstable during heating, are capable of generating EES. We demonstrated that a TCL curve can be used as a kinetic model for measuring oxidative processes, which reflects modifications of different molecules involved in the oxidative stress phenomena.

Serum Oxidative Stress Level Correlates with Clinical Parameters in Chronic Systolic Heart Failure Patients

“…2 -6 The thermochemiluminescence (TCL) oxidiziability assay (Lumitest Ltd., Haifa, Israel), measures the OS level via photon emission counting from excited carbonyls in biological macromolecules. 7 TCL measurements were previously compared to other well accepted methods, which measure serum oxidative stress level via oxidation of lipids or proteins. 8 As we demonstrated before, TCL measurements were highly correlated with thiobarbituric acid reactive substances-(TBA assay), as well as with protein carbonyl formation (r = 0.99, r = 0.98, P<.01, respectively).…”

“…8 As we demonstrated before, TCL measurements were highly correlated with thiobarbituric acid reactive substances-(TBA assay), as well as with protein carbonyl formation (r = 0.99, r = 0.98, P<.01, respectively). 7 In this study, we investigated serum OS levels in chronic HF patients and examined the relation between OS levels and other clinical and laboratory prognostic parameters. …”

Increased Serum Levels of Oxidative Stress Are Associated with Hospital Readmissions due to Acute Heart Failure

“…TCL measures the OS level via photon emission counting from excited carbonyls in biological macromolecules [5,6]. TCL measurements were validated previously by comparing them to other well-accepted methods which measure serum OS levels via oxidation of lipids or proteins [6,7,8,9].…”

Oxidative markers in cryopreservation medium from frozen-thawed embryos: a possible tool for improved embryo selection in in vitro fertilization?

“…However, these changes are currently assessed only by classical morphological grading and blastomere survival. The thermochemiluminescence (TCL) assay developed in 1994 by Shnizer et al has been used to investigate oxidative stress in biological fluids [11] and was validated in several studies using various biological samples such as the following: bovine serum albumin, polyunsaturated fatty acids [11], human and rat blood serum [12,13], human seminal plasma [14], human bronchoalveolar lavage fluid, amniotic fluid, follicular fluid [15], and embryo culture media [16].…”

“…Heating samples in the TCL Analyzer (Carmel Diagnostics, Kiryat-Tivon, Israel) [11] result in molecular oxidative modification and the formation of electronically excited species (EES) that can be measured as low chemiluminescence in the 350-600nm wavelength range. The TCL kinetic curve pattern reflects the in vitro residual oxidative capacity following in vivo molecular oxidation.…”