Expression of vitamin D-metabolizing enzymes in human adipose tissue-the effect of obesity and diet-induced weight loss.
Int J Obes (Lond). 2013 May;37(5):651-7. doi: 10.1038/ijo.2012.112. Epub 2012 Jul 17.
Wamberg L, Christiansen T, Paulsen SK, Fisker S, Rask P, Rejnmark L, Richelsen B, Pedersen SB.
Department of Endocrinology and Internal Medicine MEA, Aarhus University Hospital, Aarhus, Denmark.
Objective: Low vitamin D (VD) levels are common in obesity. We hypothesized that this may be due to metabolism of VD in adipose tissue (AT). Thus, we studied (1) whether the VD-metabolizing enzymes were expressed differently in AT of lean and obese individuals and in visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), and (2) whether their expression was influenced by weight loss.
Methods: Samples of SAT and VAT were analyzed for expression of the vitamin-D-25-hydroxylases CYP2R1, CYP2J2, CYP27A1 and CYP3A4, the 25-vitamin-D-1α-hydroxylase CYP27B1, the catabolic vitamin-D-24-hydroxylase CYP24A1, and the vitamin D receptor, using reverse transcriptase-PCR. Moreover, plasma 25-hydroxy-vitamin D (25OHD) level was measured and related to the expression of these enzymes. Samples of SAT and VAT from 20 lean women and 20 obese women, and samples of SAT from 17 obese subjects before and after a 10% weight loss were analyzed.
Results: A plasma 25OHD level <50 nmol l(-1) was highly prevalent in both lean (45%) and obese (90%) women (P<0.01). Plasma 25OHD increased by 27% after weight loss in the obese individuals (P<0.05). Expression levels of the 25-hydroxylase CYP2J2 and the 1α-hydroxylase CYP27B1 were decreased by 71% (P<0.0001) and 49% (P<0.05), respectively, in SAT of the obese. CYP24A1 did not differ between lean and obese women, but the expression was increased by 79% (P<0.05) after weight loss.
Conclusion: Obesity is characterized by a decreased expression of the 25-hydroxylase CYP2J2 and the 1α-hydroxylase CYP27B1 in SAT, whereas the catabolic CYP24A1 does not differ between lean and obese women. However, the expression of CYP24A1 is increased after weight loss. Accordingly, AT has the capacity to metabolize VD locally, and this can be dynamically altered during obesity and weight loss.
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Observation by VitaminDWiki
Various portions of the body are able to activate vitamin D locally
This study indicates that some people (obese) have less of the enzymes needed to process vitamin D locally
Hypothesis: Until the obese can change their genes they will need more vitamin D
- Vitamin D and Obesity – Review March 2013 which mentions CYP2J2
- Genes indicate that Obesity causes vitamin D deficiency – Feb 2013
- Search VitaminDWiki for CYP27B1 265 hits as of May 2013
- CYP27B1 gene decreases kidney production of active vitamin D – Feb 2013
- Genes such as CYP27B1, CYP24A1 and Vitamin D – JAMA Nov 2012
- Off topic: Can turn obesity on and off in mice with a gene – but not if obese for too long – Oct 2012
- Overview Obesity and Vitamin D
- Rediscovering vitamin D - Nov 2010 Kidney is not the only part of the body which activates vitamin D - see following chart
- The Vitamin D/ Waistline Connection Prevention Magazine review of this study, May? 2013