The milk fat globule membrane (MFGM) obtained from bovine milk is a source of bioactive compounds. In this research, the hypothesis that the MFGM possesses anticarcinogenic capacity and immune modulatory properties was tested, along with the hypothesis that processing history of the fat globules will affect the bio-functionality of the MFGM.
Throughout all experiments, lipopolysaccharide (LPS) was minimized by extracting the milk using a catheter, working under aseptic conditions and avoiding contamination via reagents. To study the anticarcinogenic capacity, native MFGM was tested in vitro using two colon adenocarcinoma cell lines (HT-29, Caco-2). Stimulated cells showed a dose-dependent decrease in cell proliferation, starting at very low concentrations (1 μg/mL based on protein) and its efficiency was comparable or even superior to the commercial anticarcinogenic drugs melphalan and C2-ceramide. Cytotoxicity and apoptosis were found to be mechanisms responsible for this bioactivity, as shown by the lactate dehydrogenase enzyme activity and the increase in caspase-3 production.
MFGM- immune modulatory capacity was also tested by studying its effects on splenocyte proliferation, apoptosis and cytokine production. While splenocyte proliferation was not affected when the MFGM isolate was used alone, it suppressed cell division in the presence of polyclonal activators (LPS, Concanavalin A) used to simulate inflammatory conditions. Cytokine production suggests inhibition of the splenocytes’ activation process as the mechanism behind its bioactivity.
Milk heating caused a significant decrease in bioactivity, indicating that protein interactions and denaturation as well as the structural changes caused by this treatment, directly affect the MFGM bio-functionality. Partial hydrolysis (by trypsin and phospholipase-A2) caused a similar effect, suggesting that not only the phospholipids are involved in the anticarcinogenic capacity, but also, the complex mixture of proteins which form part of the MFGM complete system.
In summary, the bioactivity of the MFGM extracted from milk is not limited to its anticarcinogenic but also to its immune regulatory ability, by helping control the response of the immune system when inflammatory conditions arise. However, pre-treatment of the raw material greatly affects this bioactivity, suggesting that greater care may be needed in processing of fat globules to maintain such important characteristics of their components. / Canadian Dairy Council (CDC), Ontario Dairy Council (ODC), Natural Sciences and Engineering Research Council of Canada (NSERC).
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OGU.10214/6667 |
| Date | 10 May 2013 |
| Creators | Zanabria Eyzaguirre, Romina |
| Contributors | Corredig, Milena |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Rights | http://creativecommons.org/licenses/by-nd/2.5/ca/ |
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