Bioactive peptide isolated from casein phosphopeptides promotes calcium uptake in vitro and in vivo. Issue 4 (20th March 2018)

• Record Type: Journal Article
• Authors: Liu, Guo; Sun, Shengwei; Guo, Baoyan; Miao, Benchun; Luo, Zhen; Xia, Zumeng; Ying, Danyang; Liu, Fei; Guo, Bin; Tang, Jian; Cao, Yong; Miao, Jianyin
• Is Part Of: Food & function. Volume 9:Issue 4(2018)
• Page Start: 2251
• Page End: 2260
• Publication Date: 2018-03-20
• Subjects: Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; Nutrition -- Periodicals; 664.07
• DOI: 10.1039/c7fo01709j
• Languages: English
• ISSNs: 2042-6496

Abstract

Abstract : A monomeric peptide isolated from casein phosphopeptides promoted calcium uptake in cells via the transcellular pathway and was beneficial for bone calcification in rats. Abstract : Casein phosphopeptides (CPPs) have been demonstrated to be calcium chelators. Unfortunately, few studies have been reported on the effects of CPPs on the mechanism of the uptake and absorption of Ca 2+ and bone metabolism. In this study, a monomeric peptide fraction isolated by RP-HPLC (F6-1) that possessed high calcium transport capacity in Caco-2 cell monolayers was separated and characterized. The effects of F6-1 on the absorption mechanisms of Ca 2+ in a Caco-2 monolayer model and bone metabolism in rats were investigated. F6-1 was isolated by preparative and analytical RP-HPLC. Results for calcium transport suggested that the rates of Ca 2+ transportation by F6-1 were approximately 2.57, 2.87 and 2.38 times higher than those in the control group at 30, 60 and 120 min, respectively. Results of ultraviolet (UV) spectroscopy indicated that the intensity of UV absorption changed because of the binding of Ca 2+ to F6-1. Analysis of transepithelial electrical resistance (TEER) and the expression of TRPV6 in Caco-2 cells showed that F6-1 was likely to influence the transcellular pathway of intestinal absorption of Ca 2+ rather than the paracellular pathway. Furthermore, the F6-1 group (1% Ca, 0.03% F6-1) exhibited increases in serum Ca 2+ levels, femur length and femur Ca and decreases in serum alkaline phosphatase (ALP) levels and urinary pyridinoline content in a Sprague-Dawley rat model, which implied that F6-1 was beneficial for bone calcification. Overall, our results suggested that F6-1 enhanced the transport of Ca 2+ in Caco-2 cells by affecting the transcellular pathway by upregulating the expression of TRPV6. F6-1 also improved bone formation and prevented bone resorption to benefit bone health in rats, which provided a basis for using F6-1 in calcium supplements or functional foods.