Immunogenicity of κ-Casein and Glycomacropeptide

Glycomacropeptide Protects against Inflammation and Oxidative Stress, and Promotes Wound Healing in an Atopic Dermatitis Model of Human Keratinocytes

Keratinocytes are actively implicated in the physiopathology of atopic dermatitis (AD), a skin allergy condition widely distributed worldwide. Glycomacropeptide (GMP) is a milk-derived bioactive peptide generated during cheese making processes or gastric digestion. It has antiallergic and skin barrier restoring properties when it is orally administered in experimental AD. This study aimed to evaluate the effect of GMP on the inflammatory, oxidative, proliferative, and migratory responses of HaCaT keratinocytes in an in vitro AD model. GMP protected keratinocytes from death and apoptosis in a dose dependent manner. GMP at 6.3 and 25 mg/mL, respectively, reduced nitric oxide by 50% and 83.2% as well as lipid hydroperoxides by 27.5% and 45.18% in activated HaCaT cells. The gene expression of TSLP, IL33, TARC, MDC, and NGF was significantly downregulated comparably to control by GMP treatment in activated keratinocytes, while that of cGRP was enhanced. Finally, in an AD microenvironment, GMP at 25 mg/mL stimulated HaCaT cell proliferation, while concentrations of 0.01 and 0.1 mg/mL promoted the HaCaT cell migration. Therefore, we demonstrate that GMP has anti-inflammatory and antioxidative properties and stimulates wound closure on an AD model of keratinocytes, which could support its reported bioactivity in vivo.

Protective Effect of Glycomacropeptide on Food Allergy with Gastrointestinal Manifestations in a Rat Model through Down-Regulation of Type 2 Immune Response

Glycomacropeptide (GMP) is a bioactive peptide derived from milk κ-casein with immune-modulatory and anti-inflammatory properties. Food allergy (FA) is an adverse immune reaction with a broad spectrum of manifestations. Allergen intake induces persistent intestinal inflammation and tissue damage. In this study, the anti-allergic activity of GMP was evaluated using a rat ovalbumin (OVA)-induced FA model with gastrointestinal manifestation. Rats were orally GMP treated from 3 days prior and during FA development. The severity of food anaphylaxis and diarrheal episodes, antibody production and histamine level were measured. Histopathological changes, inflammation and predominant cytokine profile at intestine were analyzed. Oral GMP intake decreased clinical signs and diarrhea severity induced by allergen, with a significant reduction in intestinal edema and expression level of IL-1β and TNF-α. Prophylaxis with GMP also diminished serum anti-OVA IgE and IgG1, and histamine levels. GMP treatment markedly decreased eosinophil infiltration, mast cell and goblet cell hyperplasia, total IgE expression in intestine, and prevented histological changes in villi, crypts and internal muscularis layer. The treatment effectively suppressed IL-5, IL-13 and GATA3 expression and skewed the intestinal cytokine profile toward type 1 and regulatory. These results suggest that GMP may protect against FA through down-regulating the type 2 inflammatory response.

Glycomacropeptide Ameliorates Indomethacin-Induced Enteropathy in Rats by Modifying Intestinal Inflammation and Oxidative Stress

Nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy is considered a serious and increasing clinical problem without available treatment. Glycomacropeptide (GMP) is a 64-amino acid peptide derived from milk κ-casein with numerous biological activities. The aim of this study was to investigate the protective effect of GMP on NSAID enteropathy in rats. Enteropathy was induced by seven days oral indomethacin administration. Rats were orally GMP treated from seven days previous and during the establishment of the enteropathy model. Changes in metabolism, hematological and biochemical blood alterations, intestinal inflammation and oxidative damage were analyzed. Integrity barrier markers, macroscopic intestinal damage and survival rate were also evaluated. GMP treatment prevented anorexia and weight loss in animals. Furthermore, prophylaxis with GMP ameliorated the decline in hemoglobin, hematocrit, albumin and total protein levels. The treatment had no therapeutic efficacy on the decrease of occludin and mucin (MUC)-2 expression in intestinal tissue. However, GMP markedly decreased neutrophil infiltration, and CXCL1, interleukin-1β and inducible nitric oxide synthase expression. Nitric oxide production and lipid hydroperoxide level in the small intestine were also diminished. These beneficial effects were mirrored by preventing ulcer development and increasing animal survival. These results suggest that GMP may protect against NSAID enteropathy through anti-inflammatory and antioxidant properties.

Glycomacropeptide Attenuates Inflammation, Pruritus, and Th2 Response Associated with Atopic Dermatitis Induced by 2,4-Dinitrochlorobenzene in Rat

Atopic dermatitis (AD) is one of the most common skin diseases, whose incidence is increasing in industrialized countries. The epicutaneous application of a hapten, such as 2,4-dinitrochlorobenzene (DNCB), evokes an experimental murine AD-like reaction. Glycomacropeptide (GMP) is a dairy bioactive peptide derived from hydrolysis of κ-casein by chymosin action. It has anti-inflammatory, prebiotic, and immunomodulatory effects. The present study was aimed to investigate the effect of GMP administration on DNCB-induced AD in rats. The severity of inflammatory process, pruritus, production of cytokines, and total immunoglobulin E (IgE) content were measured, and the histopathological features were analyzed. GMP reduced the intensity of inflammatory process and edema of DNCB-induced dermatitis, with a significant decrease in eosinophils recruitment and mast cells hyperplasia. In addition GMP suppressed the serum levels of total IgE and IL-4, IL-5, and IL-13 expression in AD-lesions. Besides, the levels of IL-10 were significantly increased. Remarkably, GMP administration before AD-induction abolished pruritus in dermatitis-like reactions in the rats. Taken together, these results indicate that GMP has an inhibitory effect on AD by downregulating Th2 dominant immune response, suggesting GMP as a potential effective alternative therapy for the prevention and management of AD.

Novel Mechanisms Underlying the Therapeutic Effect of Glycomacropeptide on Allergy: Change in Gut Microbiota, Upregulation of TGF-β, and Inhibition of Mast Cells

BACKGROUND

The prevalence of allergic diseases is globally increasing. We have previously described that glycomacropeptide (GMP), a bioactive milk peptide, has therapeutic value in experimental models of skin hypersensitivity, anaphylaxis, and asthma, as it prevents an excessive T helper type 2 cell immune response. The aim of this study was to analyze the effect of GMP on key elements directly involved in the development or control of allergy, in order to improve the precise knowledge about its mechanism of action.

METHODS

Rats were systemically sensitized with ovalbumin and orally treated with GMP. Levels of Lactobacillus, Bifidobacterium, and Bacteroides were analyzed in their feces. Splenocytes were isolated and the production of transforming growth factor (TGF)-β by allergens was measured. Intradermal skin reactions were developed to evaluate in vivo activation of mast cells. Peritoneal mast cells were isolated and activated by the allergen, and histamine secretion was determined.

RESULTS

GMP administration increased the amount of intestinal Lactobacillus and Bifidobacterium of allergen-sensitized animals after 3 days of treatment. The increase in Bacteroides was also significant, but only after 17 days of GMP administration. Ten days after treatment cessation, Lactobacillus and Bacteroides were still elevated. GMP intake also elevated the production of TGF-β in the splenocytes of sensitized animals. In addition, treatment with GMP attenuated mast cell activation by the allergen and inhibited histamine secretion, without affecting the number of mast cells.

CONCLUSIONS

The prebiotic action of GMP on allergy-protective microbiota, an increase in TGF-β production, and a reduction in mast cell response to allergens are novel mechanisms that explain the antiallergic activity of GMP.

Glycomacropeptide administration attenuates airway inflammation and remodeling associated to allergic asthma in rat

OBJECTIVE

Glycomacropeptide (GMP) is a bioactive peptide derived from milk that has been reported to exhibit a range of anti-inflammatory and immunomodulatory properties. The aim of this study was to analyze the prophylactic effect of GMP administration on airway inflammation and remodeling in an experimental model of asthmatic rat.

METHODS

Animals treated orally with or without GMP (500 mg/kg/day) were ovalbumin-sensitized and -nebulized and several indicators of Th2 response, airway structural changes and inflammatory cells recruitment were evaluated.

RESULTS

Treatment with GMP prior and during asthma development resulted in reduction of allergen-specific IgE titers in serum and blood eosinophilia. Also, GMP substantially suppressed the recruitment of inflammatory cells to bronchoalveolar compartment. Histological studies demonstrated that GMP markedly inhibits eosinophils infiltration, goblet cells hyperplasia and collagen deposit in lung tissue. The latter effect was related with an inhibition in transforming growth factor-β expression. In addition, expression of interleukin-5 and -13 were substantially inhibited in lung while that of interleukin-10 was increased.

CONCLUSION

Our results suggest that administration of GMP may prevent the development of an excessive Th2 response in asthma and effectively ameliorates the progression of the disease.

Hydrolyzed caseinomacropeptide conjugated galactooligosaccharides support the growth and enhance the bile tolerance in Lactobacillus strains

In this study bioactive caseinomacropeptide was conjugated with prebiotic galactooligosaccharides (hCMP:GOS) by Maillard reaction to synthesize value added prebiotic compounds to Lactobacillus strains. Growth study showed the ability of hCMP:GOS to serve as a sole carbon source for Lactobacillus strains. A significant amount of acetate and lactate was detected in cell free culture supernatant by HPLC. It demonstrated the ability of Lactobacillus strains to ferment the hCMP:GOS as a carbon source. In addition, hCMP:GOS grown Lactobacillus cells exhibited enhanced bile tolerance and retained 90% viability. Overall results of this study indicate that the hCMP conjugated GOS can be potential multipurpose prebiotic substrates to enhance the growth and bile tolerance in Lactobacillus strains and serve as a fermentable substrate to produce beneficial metabolites in the host.

Nanocarrier possibilities for functional targeting of bioactive peptides and proteins: state-of-the-art

This review attempts to provide an updated compilation of studies reported in the literature pertaining to production of nanocarriers encasing peptides and/or proteins, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to bioactive proteins and peptides, with a special focus on those from dairy sources (including physicochemical characteristics and properties, and biopharmaceutical application possibilities of e.g. lactoferrin and glycomacropeptide), as well as to nanocarrier functional targeting. Features associated with micro- and (multiple) nanoemulsions, micellar systems, liposomes and solid lipid nanoparticles, together with biopharmaceutical considerations, are presented in the text in a systematic fashion.

Bovine glycomacropeptide induces cytokine production in human monocytes through the stimulation of the MAPK and the NF-kappaB signal transduction pathways

BACKGROUND AND PURPOSE

Bovine glycomacropeptide (BGMP) is a natural milk peptide that is produced naturally in the gastrointestinal tract during digestion. Glycomacropepide has intestinal anti-inflammatory activity, but the mechanism of action is unknown. Here we have characterized the effects of BGMP on monocytes.

EXPERIMENTAL APPROACH

We have used human THP-1 cells as an in vitro monocyte model. The effect of BGMP on the secretion of tumour necrosis factor (TNF), interleukin (IL)-1beta and IL-8 was assessed, as well as the involvement of the NF-kappaB and MAP kinase signalling pathways. The stimulatory effect of BGMP was also tested in human peripheral blood monocytes.

KEY RESULTS

BGMP up-regulated the secretion of TNF, IL-1beta and IL-8 in a concentration-dependent fashion. The biological activity was exerted by the intact peptide, because cytokine secretion was not affected by protease inhibitors. The secretion of IL-8 and specially TNF and IL-1beta was blocked by PD98059, SP600125, SB203580 and Bay11-7082, suggesting the involvement of the MAP kinases p38, c-Jun N-terminal kinase and ERK and particularly the NF-kappaB pathway, although IL-8 secretion was independent of p38. BGMP was shown to elicit the phosphorylation of IkappaB-alpha and the nuclear translocation of the NF-kappaB subunits p50 and p65. The effect of BGMP on cytokine secretion was validated in human primary blood monocytes.

CONCLUSIONS AND IMPLICATIONS

BGMP stimulates human monocytes, operating via MAP kinase and NF-kappaB pathways. BGMP may exert an indirect intestinal anti-inflammatory effect by potentiating host defences against invading microorganisms.

Bovine glycomacropeptide ameliorates experimental rat ileitis by mechanisms involving downregulation of interleukin 17

BACKGROUND AND PURPOSE

Bovine glycomacropeptide (BGMP) is an inexpensive, non-toxic milk peptide with anti-inflammatory effects in rat experimental colitis but its mechanism of action is unclear. It is also unknown whether BGMP can ameliorate inflammation in proximal regions of the intestine. Our aim was therefore two-fold: first, to determine the anti-inflammatory activity of BGMP in the ileum; second, to characterise its mechanism of action.

EXPERIMENTAL APPROACH

We used a model of ileitis induced by trinitrobenzenesulphonic acid in rats. Rats were treated orally with BGMP and its efficacy compared with that of oral 5-aminosalicylic acid or vehicle, starting 2 days before ileitis induction.

KEY RESULTS

BGMP pretreatment (500 mg kg(-1) day(-1)) resulted in marked reduction of inflammatory injury, as assessed by lower extension of necrosis and damage score, myeloperoxidase, alkaline phosphatase, inducible nitric oxide synthase, interleukin 1beta, tumour necrosis factor and interleukin 17. These effects were generally comparable to those of 5-aminosalicylic acid (200 mg kg(-1) day(-1)). Neither compound affected the production of interferon gamma, tumour necrosis factor and interleukin 2 by mesenteric lymph node cells isolated from animals with ileitis. The expression of Foxp3 was increased in ileitis and not reduced significantly by BGMP or aminosalicylate treatment.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate that BGMP has anti-inflammatory activity in the ileum with similar efficacy to 5-aminosalicylic acid. The mechanism of action may involve Th17 and regulatory T cells and perhaps macrophages but probably not Th1 lymphocytes. Patients with Crohn's ileitis may benefit from treatment with BGMP.