Goat milk with and without increased concentrations of lysozyme improves repair of intestinal cell damage induced by enteroaggregative Escherichia coli as concluded in a study conducted on August 2012 by the following institutions:
• Department of Physiology and Pharmacology & INCT-Biomedicine, Faculty of Medicine, Federal University of Ceará, Fortaleza, Ceará, Brazil
• Department of Animal Science, University of California, Davis, CA, USA
• School of Medicine, Health Science Center, University of Fortaleza, Fortaleza, Ceará, Brazil
Human breastmilk (which contains lysozymes, protein, fats) plus goat milk together can help those with acute diarrhea caused by Enteroaggregative Escherichia coli and other bacteria. Enteroaggregative Escherichia coli (EAEC) causes diarrhea, malnutrition and poor growth in children.
The enhanced effect by the lysozyme-containing milk from transgenic animals over non-transgenic control milk may be due to the antimicrobial activity of lysozyme.
the maintenance of the epithelial barrier is essential for proper functioning and prevention of the entry of pathogenic bacteria leading to an inflammatory response.
Human breast milk decreases disease-causing bacteria by supplying nutrients and antimicrobial factors such as lysozyme. Goat milk with and without human lysozyme (HLZ) may improve the repair of intestinal barrier function damage induced by EAEC. This work investigates the effect of the milks on intestinal barrier function repair, bacterial adherence in Caco-2 and HEp-2 cells, intestinal cell proliferation, migration, viability and apoptosis in IEC-6 cells in the absence or presence of EAEC (E coli).
The study demonstrated that goat milk is able to repair intestinal barrier function damage induced by EAEC (E Coli) and that goat milk with a higher concentration of lysozyme offers additional protection. This additional protection was also reported in another recent study by the researchers from University of California, it has been found that genetically modified goat milk to contain more lysozyme can help cure E. Coli infection at a faster rate.
Researchers used rat intestinal epithelial cells that were incubated with pasteurized milk from either transgenic goats expressing HLZ or non-transgenic control goats in the presence and absence of Escherichia coli (EAEC) strain 042 (O44:H18).
Cellular proliferation was significantly greater in the presence of both HLZ transgenic and control goat milk compared to cells with no milk. Cellular migration was significantly decreased in the presence of EAEC alone but was restored in the presence of milk. Milk from HLZ transgenic goats had significantly more migration compared to control milk.
Both milks significantly reduced EAEC adhesion to Caco-2 cells and transgenic milk resulted in less colonization than control milk using a HEp-2 assay. Both milks had significantly increased cellular viability as well as less apoptosis in both the absence and presence of EAEC.
Diarrheal-causing bacteria can damage intestinal barrier function . Repair of damaged intestinal epithelial cells as a result of bacterial infection requires migration of viable cells adjacent to the site of the damage to cover the area and then cellular proliferation to replace the lost/damaged cells in order to restore normal absorptive and digestive function [1,2]. The process of cell renewal in the intestine therefore involves proliferation, migration, differentiation, apoptosis and necrosis, all of which are related to nutritional status [3,4].
Bacteria can secrete virulence factors and/or adhere to intestinal cells and prevent cellular proliferation and migration, as well as apoptosis and necrosis, four important functions required during the tissue repair process. This is particularly detrimental in young children suffering from diarrhea as diarrheal diseases are a persistent risk factor for malnutrition in many parts of the developing world.
Damage to the intestinal epithelium leads to a decreased absorptive surface area and less availability of nutrients for growth and development. Diarrheal illnesses account for over 1.5 million deaths worldwide each year with bacteria such as enteroaggregative Escherichia coli (EAEC) being one of the main causes. This type of bacteria can cause growth impairment, malnutrition and cognitive defects even in children not having active diarrhea.
The pathogenesis underlying the morbidity associated with EAEC is likely due to damage to intestinal barrier function resulting in reduced digestion and absorption of nutrients, altered cell permeability and immune and inflammatory responses. However, many questions about the mechanisms remain unanswered.
Oral rehydration solution and breastfeeding are commonly recommended as interventions for diarrheal illnesses. Oral rehydration solution can supply electrolytes to combat the dehydration associated with diarrhea and breast milk can supply key nutrients such as protein and fat as well as several innate antimicrobial proteins such as lysozyme that are thought to help contribute to a healthier gastrointestinal tract. One approach to contribute to these current therapies for diarrhea could be the administration of goat milk in general and milk containing enhanced concentrations of lysozyme.
Goat is a common source of protein worldwide in the form of both meat and milk. In terms of milk, goat milk is often more tolerable to humans with sensitivities to cows’ milk due to differences in protein and fat composition and structure. For instance, the amino acid composition of goats’ milk is closer to human milk than is cow milk and the fat globules are smaller in goat milk than in cow milk with both factors contributing the greater digestibility of goat milk compared to cow milk.
Concentration of lysozyme in human milk is 1600-3000 times greater than it is in the milk of common dairy animals such as goats and cows. Due to physiological differences, it is not possible to increase the amount of lysozyme in ruminant milk by breeding and selection. We have generated transgenic dairy goats that express human lysozyme (HLZ) in their milk at 68 % the concentrations normally found in human milk. The milk displays antimicrobial activity both in vitro and in vivo and positively impacts the state of the intestine upon consumption by animal models.
Researchers hypothesized that the consumption of goat milk and goat milk containing lysozyme could help protect and/or recover damaged intestinal epithelium resulting from bacterial infection and report here the effect of the milks on bacterial adherence and intestinal cell proliferation, migration, viability and apoptosis in the presence of EAEC, a common diarrheal pathogen.
Cell viability of IEC-6 cells with induced oxidative damage was increased by the addition of human colostrum, but not cow milk or infant formulas, and the increase was attributed to the polyamine spermine reducing the oxidative stress. Polyamines are small cationic molecules that are found in human milk and are required for intestinal growth and development.
Lysozyme also carries a net positive charge and is a relatively small protein (14 kDa) and it is likely that properties of lysozyme other than its antimicrobial function are contributing to the effect of lysozyme-rich milk.
Reference: Goat milk with and without increased concentrations of lysozyme improves repair of intestinal cell damage induced by enteroaggregative Escherichia coli Lima firstname.lastname@example.org ; BMC Gastroenterology 2012, 12:106