Using total plasma triacylglycerol to assess hepatic de novo lipogenesis as an alternative to VLDL triacylglycerol

Leanne  Hodson; Sion A. Parry; Thomas  Cornfield; Catriona  Charlton; Wee Suan  Low; Charlotte J.  Green; Fredrik  Rosqvist

doi:10.1080/03009734.2020.1739789

Leanne Hodson Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK; National Institute for Health Research Oxford Biomedical Research Centre, Oxford University Hospitals Foundation Trust, Oxford, UK
Sion A. Parry Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
Thomas Cornfield Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
Catriona Charlton Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
Wee Suan Low Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
Charlotte J. Green Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK
Fredrik Rosqvist Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, University of Oxford, Oxford, UK; Department of Public Health and Caring Sciences, Clinical Nutrition and Metabolism, Uppsala University, Uppsala, Sweden

DOI: https://doi.org/10.1080/03009734.2020.1739789

Keywords: De novo lipogenesis, DNL, hepatic, human, triacylglycerol, VLDL

Abstract

Background: Hepatic de novo lipogenesis (DNL) is ideally measured in very low-density lipoprotein (VLDL)-triacylglycerol (TAG). In the fasting state, the majority of plasma TAG typically represents VLDL-TAG; however, the merits of measuring DNL in total plasma TAG have not been assessed. This study aimed to assess the performance of DNL measured in VLDL-TAG (DNL_VLDL-TAG) compared to that measured in total plasma TAG (DNL_Plasma-TAG).

Methods: Using deuterated water, newly synthesised palmitate was determined in fasting plasma VLDL-TAG and total TAG in 63 subjects taking part in multiple studies resulting in n = 123 assessments of DNL (%new palmitate of total palmitate). Subjects were split into tertiles to investigate if DNL_Plasma-TAG could correctly classify subjects having ‘high’ (top tertile) and ‘low’ (bottom tertile) DNL. Repeatability was assessed in a subgroup (n = 16) with repeat visits.

Results: DNL_VLDL-TAG was 6.8% (IQR 3.6–10.7%) and DNL_Plasma-TAG was 7.5% (IQR 4.0%−11.0%), and the correlation between the methods was r_s = 0.62 (p < 0.0001). Bland–Altman plots demonstrated similar performance (mean difference 0.81%, p = 0.09); however, the agreement interval was wide (−9.6% to 11.2%). Compared to DNL_VLDL-TAG, 54% of subjects with low DNL were correctly classified, whilst 66% of subjects with high DNL were correctly classified using DNL_Plasma-TAG. Repeatability was acceptable (i.e. not different) at the group level, but the majority of subjects had an intra-individual variability over 25%.

Conclusion: DNL in total plasma TAG performed similarly to DNL in VLDL-TAG at the group level, but there was large variability at the individual level. We suggest that plasma TAG could be useful for comparing DNL between groups.

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