Purpose:
After a golden age of classic carnitine research three decades ago,
the spread of mass spectrometry opened new perspectives and a much better
understanding of the carnitine system is available nowadays. In the classic period,
several human and animal studies were focused on various distinct physiological
functions of this molecule and these revealed different aspects of carnitine homeostasis
in normal and pathological conditions. Initially, the laboratory analyses were based on
the classic or radioenzymatic assays, enabling only the determination of free and total
carnitine levels and calculation of total carnitine esters’ amount without any information
on the composition of the acyl groups. The introduction of mass spectrometry allowed
the measurement of free carnitine along with the specific and sensitive determination of
different carnitine esters. Beyond basic research, mass spectrometry study of carnitine
esters was introduced into the newborn screening program because of being capable to
detect more than 30 metabolic disorders simultaneously. Furthermore, mass
spectrometry measurements were performed to investigate different disease states
affecting carnitine homeostasis, such as diabetes, chronic renal failure, celiac disease,
cardiovascular diseases, autism spectrum disorder or inflammatory bowel diseases.
Results:
This article will review the recent advances in the field of carnitine research
with respect to mass spectrometric analyses of acyl-carnitines in normal and various
pathological states.
Conclusion:
The growing number of publications using mass spectrometry as a tool to
investigate normal physiological conditions or reveal potential biomarkers of primary and
secondary carnitine deficiencies shows that this tool brought a new perspective to
carnitine research.