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Importance of amino acid composition to improve skin collagen protein synthesis rates in UV-irradiated mice.

Murakami H, Shimbo K, Inoue Y, Takino Y, Kobayashi H - Amino Acids (2011)

Bottom Line: The FSR of dermal tropocollagen was measured 30 min after a single oral administration of amino acids (1 g/kg) to groups of 5-16 UVB-irradiated mice.Branched-chain amino acids (BCAA, 1.34±0.32), arginine (Arg, 1.66±0.39), glutamine (Gln, 1.75±0.60), and proline (Pro, 1.48±0.26) did not increase the FSR of skin tropocollagen compared with distilled water, which was used as a control (1.56±0.30).However, essential amino acids mixtures (BCAA+Arg+Gln, BCAA+Gln, and BCAA+Pro) significantly increased the FSR (2.07±0.58, 2.04±0.54, 2.01±0.50 and 2.07±0.59, respectively).

View Article: PubMed Central - PubMed

Affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc, 1-1 Suzuki-cho, Kawasaki, 210-8681, Japan. hitoshi_murakami@ajinomoto.com

ABSTRACT
Skin collagen metabolism abnormalities induced by ultraviolet (UV) radiation are the major causes of skin photoaging. It has been shown that the one-time exposure of UV irradiation decreases procollagen mRNA expression in dermis and that chronic UV irradiation decreases collagen amounts and induces wrinkle formation. Amino acids are generally known to regulate protein metabolism. Therefore, we investigated the effects of UV irradiation and various orally administered amino acids on skin collagen synthesis rates. Groups of 4-5 male, 8-week-old HR-1 hairless mice were irradiated with UVB (66 mJ/cm2) twice every other day, then fasted for 16 h. The fractional synthesis rate (FSR; %/h) of skin tropocollagen was evaluated by incorporating L-[ring-2H5]-phenylalanine. We confirmed that the FSR of dermal tropocollagen decreased after UVB irradiation. The FSR of dermal tropocollagen was measured 30 min after a single oral administration of amino acids (1 g/kg) to groups of 5-16 UVB-irradiated mice. Branched-chain amino acids (BCAA, 1.34±0.32), arginine (Arg, 1.66±0.39), glutamine (Gln, 1.75±0.60), and proline (Pro, 1.48±0.26) did not increase the FSR of skin tropocollagen compared with distilled water, which was used as a control (1.56±0.30). However, essential amino acids mixtures (BCAA+Arg+Gln, BCAA+Gln, and BCAA+Pro) significantly increased the FSR (2.07±0.58, 2.04±0.54, 2.01±0.50 and 2.07±0.59, respectively). This result suggests that combinations of BCAA and glutamine or proline are important for restoring dermal collagen protein synthesis impaired by UV irradiation.

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Related in: MedlinePlus

Effect of orally administered amino acids on the FSR of mixed skin protein in UVB-irradiated mice. The FSR of mixed skin protein, including dermis and epidermis, was increased by UVB irradiation. This suggests that the synthesis rate of keratin, the most abundant protein in epidermis, increases with UVB irradiation. Amino acids did not further increase the FSR of mixed skin protein. Values are presented as means ± SD. Statistical comparisons with the control group (DW, distilled water) was carried out with a Dunnett’s test after ANOVA for multiple comparisons (#P < 0.05)
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Fig4: Effect of orally administered amino acids on the FSR of mixed skin protein in UVB-irradiated mice. The FSR of mixed skin protein, including dermis and epidermis, was increased by UVB irradiation. This suggests that the synthesis rate of keratin, the most abundant protein in epidermis, increases with UVB irradiation. Amino acids did not further increase the FSR of mixed skin protein. Values are presented as means ± SD. Statistical comparisons with the control group (DW, distilled water) was carried out with a Dunnett’s test after ANOVA for multiple comparisons (#P < 0.05)

Mentions: The effect of oral amino acid administration on the FSRs of mixed skin protein is shown in Fig. 4. The FSRs of mixed skin protein were increased by UVB irradiation. However, oral amino acid administration did not affect the FSRs.Fig. 4


Importance of amino acid composition to improve skin collagen protein synthesis rates in UV-irradiated mice.

Murakami H, Shimbo K, Inoue Y, Takino Y, Kobayashi H - Amino Acids (2011)

Effect of orally administered amino acids on the FSR of mixed skin protein in UVB-irradiated mice. The FSR of mixed skin protein, including dermis and epidermis, was increased by UVB irradiation. This suggests that the synthesis rate of keratin, the most abundant protein in epidermis, increases with UVB irradiation. Amino acids did not further increase the FSR of mixed skin protein. Values are presented as means ± SD. Statistical comparisons with the control group (DW, distilled water) was carried out with a Dunnett’s test after ANOVA for multiple comparisons (#P < 0.05)
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3351609&req=5

Fig4: Effect of orally administered amino acids on the FSR of mixed skin protein in UVB-irradiated mice. The FSR of mixed skin protein, including dermis and epidermis, was increased by UVB irradiation. This suggests that the synthesis rate of keratin, the most abundant protein in epidermis, increases with UVB irradiation. Amino acids did not further increase the FSR of mixed skin protein. Values are presented as means ± SD. Statistical comparisons with the control group (DW, distilled water) was carried out with a Dunnett’s test after ANOVA for multiple comparisons (#P < 0.05)
Mentions: The effect of oral amino acid administration on the FSRs of mixed skin protein is shown in Fig. 4. The FSRs of mixed skin protein were increased by UVB irradiation. However, oral amino acid administration did not affect the FSRs.Fig. 4

Bottom Line: The FSR of dermal tropocollagen was measured 30 min after a single oral administration of amino acids (1 g/kg) to groups of 5-16 UVB-irradiated mice.Branched-chain amino acids (BCAA, 1.34±0.32), arginine (Arg, 1.66±0.39), glutamine (Gln, 1.75±0.60), and proline (Pro, 1.48±0.26) did not increase the FSR of skin tropocollagen compared with distilled water, which was used as a control (1.56±0.30).However, essential amino acids mixtures (BCAA+Arg+Gln, BCAA+Gln, and BCAA+Pro) significantly increased the FSR (2.07±0.58, 2.04±0.54, 2.01±0.50 and 2.07±0.59, respectively).

View Article: PubMed Central - PubMed

Affiliation: Frontier Research Laboratories, Institute for Innovation, Ajinomoto Co., Inc, 1-1 Suzuki-cho, Kawasaki, 210-8681, Japan. hitoshi_murakami@ajinomoto.com

ABSTRACT
Skin collagen metabolism abnormalities induced by ultraviolet (UV) radiation are the major causes of skin photoaging. It has been shown that the one-time exposure of UV irradiation decreases procollagen mRNA expression in dermis and that chronic UV irradiation decreases collagen amounts and induces wrinkle formation. Amino acids are generally known to regulate protein metabolism. Therefore, we investigated the effects of UV irradiation and various orally administered amino acids on skin collagen synthesis rates. Groups of 4-5 male, 8-week-old HR-1 hairless mice were irradiated with UVB (66 mJ/cm2) twice every other day, then fasted for 16 h. The fractional synthesis rate (FSR; %/h) of skin tropocollagen was evaluated by incorporating L-[ring-2H5]-phenylalanine. We confirmed that the FSR of dermal tropocollagen decreased after UVB irradiation. The FSR of dermal tropocollagen was measured 30 min after a single oral administration of amino acids (1 g/kg) to groups of 5-16 UVB-irradiated mice. Branched-chain amino acids (BCAA, 1.34±0.32), arginine (Arg, 1.66±0.39), glutamine (Gln, 1.75±0.60), and proline (Pro, 1.48±0.26) did not increase the FSR of skin tropocollagen compared with distilled water, which was used as a control (1.56±0.30). However, essential amino acids mixtures (BCAA+Arg+Gln, BCAA+Gln, and BCAA+Pro) significantly increased the FSR (2.07±0.58, 2.04±0.54, 2.01±0.50 and 2.07±0.59, respectively). This result suggests that combinations of BCAA and glutamine or proline are important for restoring dermal collagen protein synthesis impaired by UV irradiation.

Show MeSH
Related in: MedlinePlus