Inhibition of monocyte, lymphocyte, and neutrophil adhesion to endothelial cells by human milk oligosaccharides

Abstract

Excessive leukocyte infiltration causes severe tissue damage in a variety of inflammatory diseases. The initial step in leukocyte extravasation is mediated by selectins and oligosaccharides on their glycoconjugate ligands. Human milk is a rich source of lactose-derived oligosaccharides that are partly absorbed in the intestine and excreted with the urine. As these components contain binding determinants for the selectins we investigated whether human milk oligosaccharides are able to affect leukocyte rolling and adhesion to endothelial cells under dynamic conditions. Therefore, monocytes, lymphocytes, or neutrophils isolated from human peripheral blood were passed over TNF-alpha-activated HUVEC under shear stress. The influence of different oligosaccharide fractions was determined by video-microscopy and compared with the effects of various individual oligosaccharides. Within a physiological range (12.5 - 125 microg/ml) the acidic fraction significantly inhibited leukocyte rolling and adhesion (up to 24.0% and 52.8%, respectively) in a concentration-dependent manner. These effects were even more pronounced than those achieved by soluble sialyl-Lewis x, a physiological binding determinant for selectins. Several active components within the oligosaccharide fraction of human milk were identified, e.g. 3'-sialyl-lactose and 3'-sialyl-3-fucosyl-lactose. These results indicate that specific oligosaccharides in human milk may serve as anti-inflammatory components and might therefore contribute to the lower incidence of inflammatory diseases in human milk-fed infants.

Isolation of Milk Oligosaccharides using Solid-Phase Extraction

“…It is worth noting when interpreting this figure, and the other data presented in this study, that of the five monosaccharide constituents of HMO, only glucose and galactose are detected by the colorimetric Dubois method, and only glucose, galactose and fucose stain with the orcinol reagent on TLC plates. From the figure it is clear that the majority of carbohydrate in breast milk is lactose, and approximately 5% of glucose and galactose is bound up in oligosaccharides which is consistent with previous estimates [10].…”

“…For example, they antagonize the binding of some strains of bacteria to epithelial cells [8], and a large epidemiologic study indicated that sugar epitopes resulting from an individual genotype appear to protect against diarrhea in breast fed infants [9]. Furthermore, those containing sialic acid may serve as immune modulators [10,11]. It has also been suggested that HMO may serve as growth factors for colonic microbiota [2], as it has long been known that breast feeding results in increased levels of fecal bifidobacteria with respect to infant formula.…”

Functional Glycomic Analysis of Human Milk Glycans Reveals the Presence of Virus Receptors and Embryonic Stem Cell Biomarkers

“…For example, sialylated HMGs inhibit cholera toxin binding (15) and leukocyte adhesion to cultured human umbilical vein endothelial cells (16). Specific fucosylated HMGs are recognized by enteropathogens, including Helicobacter pylori (17), rabbit calicivirus (18), and Norwalk virus (19).…”

Classification, Structure, and Bioactive Functions of Oligosaccharides in Milk

“…Gal(β1-4)GlcNAc(β1-4)GlcNAc many of the p-selecting binding, sialylated milk oligosaccharides 3'-sialyl-lactose and 3'-sialyl-3-fucosyl lactose are the most prominent (Bode et al, 2004a). It is however identified that acidic component of milk oligosaccharides alone is more effective than total milk oligosaccharides (Schumacher et al, 2006).…”