Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Rief, M.
The role of nuclear magnetic resonance spectroscopy methods in the measurement of lipoprotein subclasses
Doktoratsstudium der Medizinischen Wissenschaft; Humanmedizin; [ Dissertation ] Medizinische Universität Graz; 2022. pp. 129
[OPEN ACCESS]
FullText
- Autor*innen der Med Uni Graz:
- Rief Martin
- Betreuer*innen:
- Metnitz Philipp
- Scharnagl Hubert
- Silbernagel Günther
- Altmetrics:
- Abstract:
- Abstract Background. Lipoproteins are essential components in (patho-) physiological functions of the human organism and have gained more and more importance in the determination of cardiovascular risk during the last decades. Various methods are used to determine lipoproteins and their subclasses, with ultracentrifugation as the reference method in routine clinical practice for the measurement of major lipoproteins (total cholesterol, triglycerides, low- and high density lipoprotein cholesterol). Another feasible measurement method is nuclear magnetic resonance (NMR) spectroscopy in the measurement of lipoprotein subclasses. To investigate the quality and quantity of NMR methods in the measurement of standard lipids and lipoprotein subclasses, a method comparison of the two most recognized NMR methods was performed. This dissertation addresses the issue of laboratory chemical measurement of lipoproteins and their subclasses by NMR. Methods. In a prospective method comparison study, serum samples were collected from one hundred and fifty patients at the Division of Internal Medicine (Clinical Division of Angiology) and the Department of Anesthesiology and Intensive Care Medicine (Division of General Anesthesiology, Emergency and Intensive Care Medicine) of the Medical University of Graz between February 17th and June 30th, 2020. Routine blood analysis was performed in the outpatient and inpatient settings. All study patients included in this method comparison study provided written informed consent in advance. Serum samples were analyzed in three laboratories: "Numares" (NMR method, Regensburg, Germany), "Labcorp" (NMR method, Burlington, North Carolina- United States of America), and "reference or standard method" (combined ultracentrifugation/precipitation also called ß-quantification, Medical University of Graz, Graz, Austria). To show the association between the major lipoproteins and subclasses between the different NMR methods and ultracentrifugation, Pearson's correlation coefficient analysis, and Passing Bablok regression were used. Results. Comparison of major lipoproteins (total cholesterol, triglycerides, low density lipoprotein cholesterol and high density lipoprotein cholesterol) between NMR methods and ultracentrifugation showed no significant differences (p<0.001) and only minor deviations in the range of mean values (<5.5%). When lipoprotein subclasses were analyzed, large differences were found between NMR methods. Particularly for particle concentrations of, for example, small low-density lipoprotein particles, a mean difference of -431 (r= 0.789 and slope 0.593) was observed. Further high deviations were also seen for Large Low Density Lipoprotein particles for example (mean difference of 300 (r= 0.607 and slope 1.272) and High Density Lipoprotein particles and subclasses. Conclucions. The equivalence of NMR and ultracentrifugation could be shown in the determination of standard lipids. In the determination of the lipoprotein subclasses, some major differences between the two NMR methods could be shown, which call into question the comparability of the two NMR methods regarding lipoprotein subclass determination. Further investigations are necessary to finally clarify whether both or only one of the NMR methods deviate from the reference method in subclass determination. It can also be stated that NMR methods are currently rarely used in clinical routine and that there is no urgent need to further expand the availability of NMR methods outside of research due to these findings.