Calcium bioaccessibility and uptake by human intestinal like cells following in vitro digestion of casein phosphopeptide-calcium aggregates.
Casein phosphopeptides (CPPs), derived by casein proteolysis, can bind calcium ions and keep them in solution. In vitro studies have demonstrated CPP-induced cell calcium uptake, depending on the formation of (CPP + calcium) complexes and on the degree of differentiation of the intestinal cells. With the present study, we address the persistence of the complexes and of the CPP-induced calcium uptake in intestinal like cells after the digestion process, thus examining their eligibility to serve as nutraceuticals. A calcium-preloaded CPP preparation of commercial origin (Ca-CPPs) was subjected to in vitro digestion. The evolution of the supramolecular structure of the Ca-CPP complexes was studied using laser-light and X-ray scattering. The bioactivity of the pre- and post-digestion Ca-CPPs was determined in differentiated Caco2 and HT-29 cells by video imaging experiments using Fura-2. We found that Ca-CPP aggregates keep a complex supramolecular organization upon digestion, despite getting smaller in size and increasing internal calcium dispersion. Concomitantly and most interestingly, digested Ca-CPPs clearly enhance the uptake of calcium ions, especially in Caco2 cells. In contrast, digestion depletes the ability of post-loaded decalcified-CPPs (Ca-dekCPPs), with a weaker internal structure, to induce calcium uptake. The enhanced bioactivity reached upon digestion strongly suggests a recognized role of Ca-CPPs, in the form used here, as nutraceuticals.
Dipartimento di Scienze Biomediche per la salute, Università degli Studi di Milano, LITA, via Fratelli Cervi 93, Milano, Italy. anita.ferraretto@unimi.it.
Silvia
S
Perego
Elena
E
Del Favero
Paola
P
De Luca
Fabrizio
F
Dal Piaz
Amelia
A
Fiorilli
Laura
L
Cantu'
Anita
A
Ferraretto
D065567:Absorption, Physiological; D000818:Animals; D018938:Caco-2 Cells; D002136:Calcium, Dietary / Q000378:metabolism*; D002364:Caseins / Q000737:chemistry / Q000378:metabolism*; D019587:Dietary Supplements; D004063:Digestion; D020895:Enterocytes / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007408:Intestinal Absorption; D018715:Microscopy, Video; D008970:Molecular Weight; D009753:Nutritive Value; D010316:Particle Size; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011492:Protein Hydrolysates / Q000737:chemistry / Q000378:metabolism; D059010:Single-Cell Analysis; D015854:Up-Regulation
D002136:Calcium, Dietary; D002364:Caseins; D010446:Peptide Fragments; D011492:Protein Hydrolysates; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex