Wound Healing Properties of Commercial Milk Hydrolysates in Intestinal Cells

Whey proteins from camel's milk have higher in vitro wound-healing effect than whey proteins from cow's milk

BACKGROUND

The effectiveness of whey obtained by either enzyme (sweet) or acid treatment on wound healing remains unclear. This study investigated the effectiveness of camel and bovine whey prepared enzymatically (CSW and BSW) or by pH reduction (CAW and BAW). After removing the cream from milk, HCl or rennet was used to remove casein, resulting in acid or sweet whey, respectively, followed by lactose removal using dialysis. Casein removal was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Wound-healing activity was measured in vitro on HT-29 cells by scratch assay. All four whey samples (0-1000 mg L-1) were applied on the cells, and the closure of the cell-free scratched areas was monitored for 48 h.

RESULTS

All whey samples increased the cell migration significantly (P < 0.05) to help close the cell-free areas as an indication of wound healing compared to the negative control. However, the closure amounts between the highest dose (1000 mg L-1) and the control were not significantly different (P > 0.05). Acid whey samples significantly (P < 0.05) elevated the closure speed compared to the sweet whey samples. The highest closure percentage (64.69%) was achieved after treatment with 10 mg L-1 CAW for 48 h. Between the sweet whey samples, BSW was significantly (P < 0.05) more effective in closing the cell-free zone compared to CSW.

CONCLUSION

This study investigated the wound-healing potential of camel and bovine whey in vitro by comparing their effects on HT-29 cell migration. CAW showed the greatest activity and may find uses as a treatment agent in wound healing. © 2024 Society of Chemical Industry.

Bioactive milk peptides: an updated comprehensive overview and database

Partial digestion of milk proteins leads to the formation of numerous bioactive peptides. Previously, our research team thoroughly examined the decades of existing literature on milk bioactive peptides across species to construct the milk bioactive peptide database (MBPDB). Herein, we provide a comprehensive update to the data within the MBPDB and a review of the current state of research for each functional category from in vitro to animal and clinical studies, including angiotensin-converting enzyme (ACE)-inhibitory, antimicrobial, antioxidant, dipeptidyl peptidase (DPP)-IV inhibitory, opioid, anti-inflammatory, immunomodulatory, calcium absorption and bone health and anticancer activity. This information will help drive future research on the bioactivities of milk peptides.

Food Safety Assessment and Nutraceutical Outcomes of Dairy By-Products: Ovine Milk Whey as Wound Repair Enhancer on Injured Human Primary Gingival Fibroblasts

The valorization of milk whey appears to be a promising strategy for managing by-products from dairy food industries, which incur demanding economic costs for treatment and/or disposal. Thanks to its numerous bioactive components, whey is expected to be increasingly incorporated into foods in the future. We investigated the safety of ovine milk whey through in vitro experiments on human primary gingival fibroblast (HGF-1) proliferation and wound healing. Fibroblasts play a crucial role in the repair processes from the late inflammatory phase until the final stages. Cells treated with varying concentrations of ovine whey (0.01%, 0.1%, 1%, and 10%) were able to close wounds more rapidly than vehicle-treated cells. Time- and dose-dependent responses were observed in cell populations exposed to ovine whey. Specifically, wounds treated with 0.1% and 10% milk whey showed better migratory capabilities compared to those treated with 0.01% and 1% milk whey after 24 and 48 h. In addition, ovine milk whey stimulates extracellular matrix deposition, as evidenced by the increasing levels of CD44 antigen density evaluated through FACS analysis, as well as COL1A1 expression measured both via RT-qPCR and immunofluorescence. This phenomenon was particularly evident at concentrations of 0.01% and 10%. Ensuring quality and safety has become a major concern for health authorities in the food industry. Our findings suggest that ovine milk whey is safe and possesses regenerative properties. It facilitates tissue re-establishment following exposure to environmental stress, particularly accelerating gingival wound closure.

Suppression of inflammatory responses in heat-stressed broiler chickens by bovine casein

This study was conducted to investigate the potential of bovine casein to mitigate the inflammatory responses in heat-stressed broiler chickens. One-day-old Ross 308 male broiler chickens (n = 1200) were reared using standard management practices. On d 22 of age, birds were divided into 2 main groups and kept either under thermoneutral temperature (21 ± 1 °C) or chronic heat stress (30 ± 1 °C). Each group was further divided into 2 sub-groups and fed either the control diet (Con) or the casein (3 g/kg) supplemented diet (CAS). The study consisted of four treatments; each treatment was replicated 12 times with 25 birds per replicate. The treatments were as follow; CCon: control temperature + control diet, CCAS: control temperature + casein diet, HCon: heat stress + control diet, and HCAS: heat stress + casein diet. The casein and heat stress protocols were applied from d 22 to d 35 of age. Casein increased the growth performance of the HCAS (P < 0.05) when compared to the HCon. Additionally, the maximum feed conversion efficiency was exhibited (P < 0.05) by the HCAS. Compared with CCon, heat stress increased (P < 0.05) the levels of proinflammatory cytokines. Casein lowered (P < 0.05) the levels of proinflammatory cytokines and increased (P < 0.05) the levels of anti-inflammatory cytokines in response to heat exposure. Heat stress decreased (P < 0.05) villus height, crypt depth, villus surface area, and absorptive epithelial cell area. Casein increased (P < 0.05) villus height, crypt depth, villus surface area, and absorptive epithelial cell area in CCAS and HCAS. Furthermore, casein improved intestinal microflora balance by enhancing (P < 0.05) the growth of intestinal beneficial bacteria and decreasing (P < 0.05) the intestinal colonization with the pathogenic bacteria. In conclusion, dietary inclusion of bovine casein would suppress the inflammatory responses in heat-stressed broiler chickens. Such potential could be utilized as an effective management approach to promote gut health and homeostasis during heat stress conditions.

Fast acting hemostatic agent based on self-assembled hybrid nanofibers from chitosan and casein

Hemorrhage is a leading cause of preventable death in both military combat and civilian accidents. To overcome these challenges, an affordable and effective bandage is must required substance. A novel strategy is reported for developing chitosan-casein (CC) based self-assembled nanofibrous polyelectrolyte complex (PEC) for rapid blood clotting. The amide group (1630 cm-1) and phosphate group (910 cm-1) of chitosan-casein can form PEC at pH 8.2 ± 0.2. The PECs contain intertwined nanofibers (≤100 nm diameter) with a high surface area. Increasing chitosan percentage from 30% (CC30) to 50% (CC50) or 70% (CC70) results, increase in zeta potential of PEC from -9.14 ± 3.3 to 7.46 ± 3.7 and 14.8 ± 3.3 mV, respectively. Under in vitro conditions, the CC30, CC50, and CC70 PECs allow platelet adhesion and rapidly absorbs blood fluid to form mechanically stable blood clots within 9 ± 3, 16 ± 3, and 30 ± 4 s, respectively, which are better than Celox™ (90 ± 3 s). In vivo application of PEC (CC50) causes clotting within 37 ± 6 s of large (1 cm) arterial incision in rabbit models. The PEC is biocompatible with promising hemostatic efficiency. This is the first report of nanofibrous PEC from chitosan and casein for rapid clotting, to the best of our knowledge.

Differences and Similarities in the Peptide Profile of Preterm and Term Mother's Milk, and Preterm and Term Infant Gastric Samples

Our previous studies revealed that milk proteases begin to hydrolyze proteins in the mammary gland and that proteolytic digestion continues within the infant stomach. No research has measured how the release of milk peptides differs between the gastric aspirates of term and premature infants. This study examined the presence of milk peptides in milk and gastric samples from term and preterm infants using an Orbitrap Fusion Lumos mass spectrometer. Samples were collected from nine preterm-delivering and four term-delivering mother-infant pairs. Our study reveals an increased count and ion abundance of peptides and decreased peptide length from mother's milk to the infant stomach, confirming that additional break-down of the milk proteins occurred in both preterm and term infants' stomachs. Protein digestion occurred at a higher level in the gastric contents of term infants than in gastric contents of preterm infants. An amino acid cleavage site-based enzyme analysis suggested that the observed higher proteolysis in the term infants was due to higher pepsin/cathepsin D activity in the stomach. Additionally, there was a higher quantity of antimicrobial peptides in term infant gastric contents than in those of preterm infants, which could indicate that preterm infants benefit less from bioactive peptides in the gut.

In vitro-digested milk proteins: Evaluation of angiotensin-1-converting enzyme inhibitory and antioxidant activities, peptidomic profile, and mucin gene expression in HT29-MTX cells

Over the past decades, several studies investigated the health-promoting functions of milk peptides. However, to date many hurdles still exist regarding the widespread use of milk-derived bioactive peptides, as they may be degraded during gastrointestinal digestion. Thus, the aim of our study was to in vitro digest intact whey protein isolate (WPI) and casein proteins (CNP), mimicking in vivo digestion, to investigate their bioactive effects and to identify the potential peptides involved. Whey protein isolate and CNP were digested using a pepsin-pancreatin protocol and ultra-filtered (3-kDa cutoff membrane). A permeate (<3 kDa) and a retentate (>3 kDa) were obtained. Soy protein was included as a control (CTR). Angiotensin-1-converting enzyme inhibitory (ACE1-I) and antioxidant activity (AOX) were assessed and compared with those observed in undigested proteins and CTR. Furthermore, the permeate was characterized by nano-liquid chromatography electrospray ionization tandem mass spectrometry (LC-nano ESI MS/MS) using a shotgun peptidomic approach, and retentate was further digested with trypsin and analyzed by MS using a shotgun proteomic approach to identify potentially bioactive peptides. Further, the effects of WPI, CNP, and CTR retentate on cell metabolic activity and on mucus production (MUC5AC and MUC2 gene expression) were assessed in intestinal goblet HT29-MTX-E12 cells. Results showed that WPI permeate induced a significant ACE1-I inhibitory effect [49.2 ± 0.64% (SEM)] compared with undigested WPI, CNP permeate, and retentate or CTR permeate (10.40 ± 1.07%). A significant increase in AOX (1.58 ± 0.04 and 1.61 ± 0.02 µmol of trolox AOX equivalents per mg of protein, respectively) upon digestion was found in WPI. Potentially bioactive peptides associated with ACE1-I and antihypertensive effects were identified in WPI permeate and CNP retentate. At specific concentrations, WPI, CNP, and CTR retentate were able to stimulate metabolic activity in HT29-MTX-E12 cells. Expression of MUC5AC was increased by CNP retentate and unaltered by WPI retentate; MUC2 expression was significantly increased by 0.33 mg/g of CNP and reduced by 1.33 mg/g of CNP. Our results confirm that milk proteins may be rich sources of bioactive compounds, with the greatest beneficial potential of CNP at the intestinal goblet cell level.

Effect of Casein Hydrolysates on Intestinal Cell Migration and Their Peptide Profiles by LC-ESI/MS/MS

Potential beneficial effects of bioactive peptides derived from casein on epithelial cellular wound healing in the gastrointestinal tract were studied. Bovine casein was digested by a combination of pepsin and pancreatic proteases at different time intervals to represent ranges of duration of gastrointestinal digestion. Intestinal epithelial cells were used as an in vitro model of the small intestine. The effect of casein hydrolysates on cell migration was studied by scratch assay as a model of wound healing. Casein digested by pepsin and pancreatin for 10 to 30 min were found to have a significant stimulatory effect of >40% on cell migration relative to the control. A potential effect of casein gastrointestinal digests on gastro-intestinal wound healing has not previously been reported. The peptide profiles of active as well as inactive casein hydrolysates were characterised by liquid chromatography coupled to ion trap tandem mass spectrometry. By comparison of identified peptides in active and inactive casein hydrolysates, a pool of 11 peptides derived from casein were identified as potential candidates for effects on cell migration. Searching the milk bioactive peptide database (MBPDB) showed that 15 of the identified peptides had known biological functions such as antimicrobial, antioxidant, and immunomodulatory activity.