Growth factors from bovine milk and colostrum: composition, extraction and biological activities

Abstract

-EGF, BTC, IGF-I, IGF-II, TGF-β1, TGF-β2, FGF1 and 2, and PDGF are the main growth factors present in bovine milk and colostrum. All of these growth factors are also found in human milk but at a lower concentration. The various compositional data reported in the literature vary greatly but it is evidenced that the day of lactation has the most important effect. Milk growth factors are characterized by a neutral to alkaline isoelectric point (pI) and a molecular mass between 6400 g·mol -1 and 30000 g·mol -1 . However, many of the growth factors are in a latent form, bound to high-molecular-mass proteins. Milk growth factors are resistant generally to pasteurization but disulfide reducing agents have been found to inactivate some species such as TGF-β's. The published data on bioavailability of milk growth factors are somewhat contradictory but it is generally accepted that they are resistant to gastric digestion and they can exert local and systemic effects on the gastrointestinal tract. Cation-exchange chromatography has been widely used for the extraction of milk growth factors because of the basic nature of these molecules. Membrane separations such as microfiltration (MF) have also been used successfully for the extraction of immunoglobulins and of some growth factors from colostrum, while ultrafiltration (UF) was successful only at separating IGF-I and IGF-II in whey. Milk growth factor extracts have been developed for various applications such as treatment of gastrointestinal disorders and skin diseases, wound healing, and induction of oral tolerance.

Invited review: Aspects of gastrointestinal tract growth and maturation in the pre- and postweaning period of pigs

“…Colostrum and milk, but especially colostrum, are also rich sources of a suite of compounds such as growth factors, hormones, cells, and antimicrobial factors, including lactoferrin, lysozyme, lactoperoxidase, and cytokines (e.g., IL-1β, IL-6, TNF-α, IFN-γ, and IL-1ra), which in one way or another are involved in the stimulation and regulation of the growth and development of the GIT in this period (e.g., Burrin et al, 1995;Donovan and Odle, 1994;Xu, 1996;Sangild et al, 2000;Xu et al, 2000;Odle et al, 1996;Gauthier et al, 2006;Boudry et al, 2008). It is outside the scope of this review to discuss each (isolated) growth factor/ compound and its effects on the structure and function of the GIT for young pigs; however, interest has focused particularly on the properties and roles of epidermal growth factor (EGF), the insulin-like growth factors, insulin, and other compounds such as transforming growth factor.…”

Transforming growth factor-β2 and endotoxin interact to regulate homeostasis via interleukin-8 levels in the immature intestine

“…Transforming growth factor-␤2 (TGF-␤2) is a multifunctional growth factor that is present in both human (ϳ0.1-5.3 ng/ml) and bovine (ϳ13-1,150 ng/ml) milk as the most dominant isoform of the TGF-␤ family (2,8). TGF-␤s have been reported to exert various functions in the gut in vivo, such as immunomodulation (30), regulation of intestinal cell proliferation and differentiation (9,40), and protection against intestinal injury in a NEC-like model (19).…”

Effect of Milk Renewal on Cell Viability In Vitro at Different Time Frames

“…Besides having low bacterial content (3,4), physiologic osmolality (230-270 mOsm/kg) and neutral pH (6.5-6.8), it provides the cells with nutrients (3) and growth factors (12,13). Although there has been some controversy (6,8), it has been suggested that milk with a lower fat content might be more appropriate to maintain PDLF viability than milk with a higher fat content (14).…”