articLe | DERMONUTRITION |
Figure 1 Metabolism of linoleic acid. Picture from Fan & Chapkin 1998 (7)
in a murine model (18). Using the literature, Danone Research decided to
formulate a dairy product containing borage oil (BO), GTPs, vitamin E, and probiotics that would be important for improving skin barrier function. The effects of GLA‑containing borage oil and GTPs were evaluated on epidermal differentiation in vitro and the effects of the complete ingredient mixture on filaggrin biosynthesis in organotypic living skin equivalents. The bioavailability and then the efficacy of this fermented dairy product, containing BO, GTPs, and vitamin E, were investigated in vivo for their effects on skin barrier function.
nutrient for skin because only the liver can biotransform
LA to GLA. Human skin is not able to biosynthesise GLA from its precursor acid (LA), because of a lack of the enzyme delta‑6 desaturase (Figure 1) (7), and its rate of transformation can be reduced, for instance, in ageing or in subjects under psychological stress (8). Skin is, therefore, especially dependent on and sensitive to changes in the blood levels of GLA. Furthermore, the importance of GLA for the skin is clearly demonstrated in animal models of essential fatty acid deficiency (EFAD), where the rate of recovery of skin barrier function is faster for topically applied GLA compared, for example, with that of LA (9). It is important to note here that alpha‑linolenic acid, an omega‑3 PUFA (C18:3ω3), seems to be much less effective than GLA (10). In addition, two oral intervention studies with capsule supplements are pertinent (11,12), and demonstrated that GLA‑enriched oils improved skin barrier function. The effect of polyphenols and other antioxidants on
Probiotics
can beneficially affect host health by improving microbial balance.
Involucrin Involucrin
skin barrier function is also interesting. Green tea polyphenols (GTP) have many effects on the cellular and molecular responses in the epidermis (13), but more importantly are the effects of this general class of ingredients on TEWL. For instance, one study showed that daily ingestion of cocoa polyphenols improved skin barrier function (14). Equally, vitamin E (the most important lipid‑soluble, membrane bound antioxidant in the body) was shown to have skin barrier–stabilising properties (15). Furthermore, an in vitro study reported that vitamin E applied on living skin equivalent cultures also reduced TEWL (16). Probiotics is another class of nutrients presenting
interesting properties for skin care. Probiotics can beneficially affect host health by improving microbial balance. Naturally, they can only deliver their skin effects indirectly via the circulatory system when eaten. Some studies reported that they reduced infantile atopic eczema/dermatitis syndrome, conditions associated with an impaired skin barrier function (17). Other studies showed that they reduced T‑cell–mediated inflammation
34 ❚ May 2011 |
prime-journal.com Figure 2 Effect of
GLA-containing borage oil and GTPs on expression of keratinocyte involucrin (a) and transglutaminase (b). Values were expressed as mean ± SEM
100 80 60 40 20 0
100 80 60 40 20 0
GLA10 GLA10
** **
* *
In vitro skin studies The effects of GLA‑containing borage oil and GTPs on keratinocyte differentiation in monolayer cultures containing low calcium were examined. Involucrin and transglutaminase were chosen as markers and measured using enzyme‑linked immunosorbent assays (ELISA). At 10 μM concentrations GLA and GTPs on their own had only a marginal effect on the expression of transglutaminase, whereas GTPs increased the expression of involucrin independently. However, when combined, both ingredients had a marked effect on the expression of both proteins (Figures 2a and 2b). To examine the effects of the ingredients on filaggrin
expression, skin equivalents were used. Mimeskin® organotypic living skin equivalents were prepared by adding a suspension of 250 000 fibroblasts/cm2
on top
GTE10 GTE10
GLA10 GTE10 GLA10 GTE10
* Significantly different to GLA10 μΜ ** Significantly different to both GLA10 μΜ and GTE10 μΜ
* Significantly different to GLA10 μΜ ** Significantly different to both GLA10 μΜ and GTE10 μΜ
Transglutaminase Transglutaminase
1000 800 600 400 200 0
1000 800 600 400 200 0
GLA10 GLA10
GTE10 GTE10
GLA10 GTE10 GLA10 GTE10
Transglutaminase levels ng 100µg-1 protein
Transglutaminase levels ng 100µg-1 protein
Involucrin levels ng 100µg-1 protein
Involucrin levels ng 100µg-1 protein
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84