Identification of nestin-positive putative mammary stem cells in human breastmilk

Abstract

Stem cells in mammary tissue have been well characterised by using the mammary stem cell marker, cytokeratin (CK) 5 and the mature epithelial markers CK14, CK18 and CK19. As these markers have never been reported in cells from breastmilk, the aim of this study has been to determine whether mammary stem cells are present in expressed human breastmilk. Cultured cells from human breastmilk were studied by using immunofluorescent labelling and reverse transcription/polymerase chain reaction (RT-PCR). We found a heterogeneous population of cells with differential expression of CK5, CK14, CK18 and CK19. Further, by using the multipotent stem cell marker, nestin, we identified cells in culture that were positive only for nestin or double-positive for CK5/nestin, whereas no co-staining was observed for CK14, CK18 and CK19 with nestin. When cells isolated from breastmilk were analysed by using RT-PCR prior to culture, only nestin and CK18 were detected, thereby indicating that breastmilk contained differentiated epithelial and putative stem cells. Furthermore, fluorescence-activated cell-sorting analysis demonstrated, in breastmilk, a small side-population of cells that excluded Hoechst 33342 (a key property of multipotent stem cells). When stained for nestin, the cells in the side-population were positive, whereas those not in the side-population were negative. The presence of nestin-positive putative mammary stem cells suggests that human breastmilk is a readily available and non-invasive source of putative mammary stem cells that may be useful for research into both mammary gland biology and more general stem cell biology.

Exploring the stem cell and non-stem cell constituents of human breast milk

“…In addition, the work also demonstrated the expression of certain unique markers of dendritic cells, and of myoepithelial progenitors and of platelet derived growth factor that are responsible for immunity, growth, migration and angiogenesis. Overall, the percentages of expressions of all cell surface markers analysed in our study was found to be much higher than that in earlier reports (Patki et al 2010;Fan et al 2010;Cregan et al 2007). Moreover, there was also a variation seen in the percentage of expression within the twenty-six samples for all markers.…”

“…Regardless of the accumulating evidences on the existence of stem cells in human breast milk (Patki et al 2010;Fan et al 2010;Cregan et al 2007), there seems to be paucity of information pertaining to its cellular constituents. Besides, it was believed that breast milk derived stem cells possess a colossal regenerative potency that can be used for treating a wide horizon of neonatal disorders.…”

“…Nevertheless, the existence of MSC derived from different sources such as tendon (Salingcarnboriboon et al 2003), periodontal ligament (Seo et al 2004), synovial membrane (De Bari et al 2001, lung (Sabatini et al 2005, liver (Campagnoli et al 2001), endometrial tissue (Musina et al 2008) and body/tissue fluids such as synovial fluid (Jones et al 2004), amniotic fluid (Tsai et al 2004;In 't Anker et al 2003;Kim et al 2007) and menstrual blood (Gargett et al 2009;Schwab and Gargett 2007), and their immune potency has been discovered in the past decade. Furthermore, stem cell constituents of breast milk and their therapeutic application has been a fascinating area of research in recent years (Patki et al 2010;Fan et al 2010;Cregan et al 2007).…”

“…The existence of putative mammary stem cell population has been reported in breast milk with the expression of markers such as CK5, CK14, CK 19 and nestin (Fan et al 2010;Cregan et al 2007). Besides, human breast milk was also identified to possess heterogeneous cellular components such as mesenchymal stem cells (MSC), hematopoietic stem cells (HSC), side population (SP) and endothelial cells (Patki et al 2010;Fan et al 2010).…”

Breastfeeding-related maternal microchimerism

“…Most CD4 + and CD8 + T cells are effector memory cells 7,8 . Up to 6% of breast milk cells are progenitor or stem cells of haemopoietic, mesenchymal and neuroepithelial lineages 9,10 . Some of these cells express markers that suggest a mesenchymal stem cell phenotype (CD90, CD44, CD271 and CD146), some express markers of em bryonic stem cells (TRA-1-60, octamer-binding protein 4 (OCT4), NANOG and SOX2) and some express markers of luminal mammary epithelial cells (cytokeratin 18) 11 .…”