546
F. Tourniaire et al.
(Chung et al. 2009). However, these correlations vary largely and are strongly influenced by the gender. Notably, El-Sohemy et al. reported correlation coefficients in
women between intake and concentration in adipose tissues of α-, β-carotene, βcryptoxanthin, and lutein/zeaxanthin (0.25, 0.29, 0.44 and 0.17 respectively), but not
in men (0.04, 0.07, 0.23, and 0.06, respectively) (El-Sohemy et al. 2002). The origin
of the discrepancy is presently unknown but suggests that carotenoids adipose tissue
concentration may be affected by factors other than intake, or that carotenoid intake
is not appropriately estimated.
Adipose tissue carotenoids content is not only correlated with dietary intake, but
also with other tissues concentration. Thus, lutein adipose tissue content has also been
reported to be positively correlated with macular pigment density in men, but not
in women (Broekmans et al. 2002). In addition, total carotenoid content in adipose
tissue is strongly associated to serum levels (Chung et al. 2009), except for lycopene
and lutein + zeaxanthin. β-carotene content in adipose tissue is correlated to plasma
level with a correlation coefficient of 0.20 (Kardinaal et al. 1995; Su et al. 1998).
Similarly, breast adipose tissue carotenoids content correlates with plasma levels,
except for β-cryptoxanthin (Yeum et al. 1998).
21.3.2 Carotenoids Are Metabolized in Adipocytes
and Adipose Tissue
β-carotene 15, 15
-monooxygenase (BCO1; involved in centric cleavage of
carotenoids) and β-carotene 9
, 10
-dioxygenase (BCDO2; involved in eccentric
cleavage of carotenoids) are expressed in adipocytes (Hessel et al. 2007), raising
the possibility that carotenoid cleavage products, including retinal, derivatives and
apocarotenoids could be found in adipocytes (Coronel et al. 2019; Amengual et al.
2011; Tourniaire et al. 2009). In agreement retinal (Ziouzenkova et al. 2007), as well
as free retinol has been identified in the adipocyte fraction of adipose tissue (Tsutsumi
et al. 1992). Several isomers of retinol, including all-trans, 9-cis and 13-cis isomers,
were also quantified in white adipose tissue (Tsutsumi et al. 1992; Kane 2012; Sima
et al. 2011), together with several isomers of retinoic acid, except 9-cis retinoic acid
(Kane 2012; O’Byrne et al. 2005; Landrier et al. 2017). Adipocytes express BCO1
and BCO2, as well as the enzymes necessary for vitamin A metabolism, suggesting
that part of the effect of provitamin A carotenoids are mediated via vitamin A production. This topic will not be developed in the present review and the reader is referred
to the excellent review of Dr. Blaner (2019).
Besides these retinoids, β-10
-apocarotenal has been identified in adipose tissue
(Amengual et al. 2011). It is highly probable that other apocarotenoids are produced
in adipose tissue, nevertheless, the function of those compounds in adipocyte biology
still needs to be investigated.
F. Tourniaire et al.
(Chung et al. 2009). However, these correlations vary largely and are strongly influenced by the gender. Notably, El-Sohemy et al. reported correlation coefficients in
women between intake and concentration in adipose tissues of α-, β-carotene, βcryptoxanthin, and lutein/zeaxanthin (0.25, 0.29, 0.44 and 0.17 respectively), but not
in men (0.04, 0.07, 0.23, and 0.06, respectively) (El-Sohemy et al. 2002). The origin
of the discrepancy is presently unknown but suggests that carotenoids adipose tissue
concentration may be affected by factors other than intake, or that carotenoid intake
is not appropriately estimated.
Adipose tissue carotenoids content is not only correlated with dietary intake, but
also with other tissues concentration. Thus, lutein adipose tissue content has also been
reported to be positively correlated with macular pigment density in men, but not
in women (Broekmans et al. 2002). In addition, total carotenoid content in adipose
tissue is strongly associated to serum levels (Chung et al. 2009), except for lycopene
and lutein + zeaxanthin. β-carotene content in adipose tissue is correlated to plasma
level with a correlation coefficient of 0.20 (Kardinaal et al. 1995; Su et al. 1998).
Similarly, breast adipose tissue carotenoids content correlates with plasma levels,
except for β-cryptoxanthin (Yeum et al. 1998).
21.3.2 Carotenoids Are Metabolized in Adipocytes
and Adipose Tissue
β-carotene 15, 15
-monooxygenase (BCO1; involved in centric cleavage of
carotenoids) and β-carotene 9
, 10
-dioxygenase (BCDO2; involved in eccentric
cleavage of carotenoids) are expressed in adipocytes (Hessel et al. 2007), raising
the possibility that carotenoid cleavage products, including retinal, derivatives and
apocarotenoids could be found in adipocytes (Coronel et al. 2019; Amengual et al.
2011; Tourniaire et al. 2009). In agreement retinal (Ziouzenkova et al. 2007), as well
as free retinol has been identified in the adipocyte fraction of adipose tissue (Tsutsumi
et al. 1992). Several isomers of retinol, including all-trans, 9-cis and 13-cis isomers,
were also quantified in white adipose tissue (Tsutsumi et al. 1992; Kane 2012; Sima
et al. 2011), together with several isomers of retinoic acid, except 9-cis retinoic acid
(Kane 2012; O’Byrne et al. 2005; Landrier et al. 2017). Adipocytes express BCO1
and BCO2, as well as the enzymes necessary for vitamin A metabolism, suggesting
that part of the effect of provitamin A carotenoids are mediated via vitamin A production. This topic will not be developed in the present review and the reader is referred
to the excellent review of Dr. Blaner (2019).
Besides these retinoids, β-10
-apocarotenal has been identified in adipose tissue
(Amengual et al. 2011). It is highly probable that other apocarotenoids are produced
in adipose tissue, nevertheless, the function of those compounds in adipocyte biology
still needs to be investigated.