The mammary gland undergoes significant remodeling during pregnancy and lactation, which is fuelled by controlled mammary stem cell (MaSC) proliferation. The scarcity of human lactating breast tissue specimens and the low numbers and quiescent state of MaSCs in the resting breast have hindered understanding of both normal MaSC dynamics and the molecular determinants that drive their aberrant self-renewal in breast cancer. Here, we demonstrate that human breastmilk contains stem cells (hBSCs) with multilineage properties. Breastmilk cells from different donors displayed variable expression of pluripotency genes normally found in human embryonic stem cells (hESCs). These genes included the transcription factors (TFs) OCT4, SOX2, NANOG, known to constitute the core self-renewal circuitry of hESCs. When cultured in the presence of mouse embryonic feeder fibroblasts, a population of hBSCs exhibited an encapsulated ESC-like colony morphology and phenotype and could be passaged in secondary and tertiary clonogenic cultures. While self-renewal TFs were found silenced in the normal resting epithelium, they were dramatically upregulated in breastmilk cells cultured in 3D spheroid conditions. Furthermore, hBSCs differentiated in vitro into cell lineages from all three germ layers. These findings provide evidence that breastmilk represents a novel and noninvasive source of patient-specific stem cells with multilineage potential and establish a method for expansion of these cells in culture. They also highlight the potential of these cells to be used as novel models to understand adult stem cell plasticity and breast cancer, with potential use in bioengineering and tissue regeneration. Stem Cells2012;30:2164–2174

Background: Breastfeeding durations in the United States fall short of public health objectives. We sought to quantify the prevalence and identify risk factors for early, undesired weaning that mothers attribute to physiologic difficulties with breastfeeding. Methods: We analyzed data from the Infant Feeding Practices Study (IFPS) II, a longitudinal study of US women. We defined disrupted lactation as early, undesired weaning attributed to at least two of the following three problems: breast pain, low milk supply, and difficulty with infant latch. We used logistic regression to estimate the association maternal body mass index (BMI), postpartum depressive symptoms, and disrupted lactation. Results: Of 4,902 women enrolled in the IFPS II, we analyzed 2,335 women who reported prenatal intention and breastfeeding initiation. The prevalence of disrupted lactation was 12 per 100 women (95% confidence interval [CI] 11, 13) during the first year of life. Women in this group weaned earlier (median 1.2 months, interquartile range [IQR] 0.5-2.8) than women without disrupted lactation (median 7.0 months, IQR 2.8-2.0, p < 0.01). In multivariable-adjusted (MV-adj.) models, we found increased odds of disrupted lactation among overweight (odds ratio [OR] 1.6, 95% CI 1.1-2.3) or obese (OR 1.7, 95% CI 1.2-2.6) women, compared with women with a normal pregravid BMI. Maternal depressive symptoms at 2 months, defined as Edinburgh Postnatal Depression Scale ‡ 13, were also associated with disrupted lactation (MV-adj. OR 1.7, 95% CI 1.1-2.7). Conclusion: In a longitudinal sample of US women, disrupted lactation affected one in eight mothers who initiated breastfeeding. These findings underscore the need for both improved early breastfeeding support and targeted research to define the underlying pathophysiology and to determine management strategies that will enable more mothers to achieve their breastfeeding goals.

Breastmilk is a rich source of cells with a heterogeneous composition comprising early-stage stem cells, progenitors and more differentiated cells. The gene expression profiles of these cells and their associations with characteristics of the breastfeeding mother and infant are poorly understood. This study investigated factors associated with the cellular dynamics of breastmilk and explored variations amongst women. Genes representing different breastmilk cell populations including mammary epithelial and myoepithelial cells, progenitors, and multi-lineage stem cells showed great variation in expression. Stem cell markers ESRRB and CK5, myoepithelial marker CK14, and lactocyte marker α-lactalbumin were amongst the genes most highly expressed across all samples tested. Genes exerting similar functions, such as either stem cell regulation or milk production, were found to be closely associated. Infant gestational age at delivery and changes in maternal bra cup size between pre-pregnancy and postpartum lactation were associated with expression of genes controlling stemness as well as milk synthesis. Additional correlations were found between genes and dyad characteristics, which may explain abnormalities related to low breastmilk supply or preterm birth. Our findings highlight the heterogeneity of breastmilk cell content and its changes associated with characteristics of the breastfeeding dyad that may reflect changing infant needs.

BackgroundBreastfeeding provides numerous health benefits for mothers and infants, but worldwide breastfeeding rates fall below recommendations. As part of efforts to increase breastfeeding initiation and duration, the World Health Organization and UNICEF UK recommend educational interventions to increase awareness and positive attitudes towards breastfeeding beginning during the school years. Breastfeeding education in the school setting offers the opportunity to improve the knowledge base, address misconceptions, and positively influence beliefs and attitudes for students from a wide range of socioeconomic and cultural backgrounds. The purpose of this paper is to present a comprehensive narrative review of the literature regarding student and teacher (stakeholder) views of breastfeeding and breastfeeding education programs in schools to inform future research in the area.MethodsArticles were located through a systematic search of online databases and journals using the following keywords in various combinations: (1) breastfeeding, lactation, breast-feeding, “bottle feeding”, “infant feeding” (2) student, educator, teacher, “school administrator” and (3) schools, “secondary education”, “primary education”, “K-12”, “high school”, “middle school”, “elementary school”, education, adolescents, curriculum, and a manual search of article references. Studies were screened for inclusion against specific criteria and included papers were assessed using the Mixed Methods Appraisal Tool (MMAT).ResultsThis review suggests that adolescents have a deficit in breastfeeding knowledge and express negative conceptions about breastfeeding. Breastfeeding is being discussed in some school environments, but the extent of lessons and the specific messages that teachers communicate have not been explored. Students appear to be interested in receiving more information about breastfeeding, especially if delivered by health professionals or breastfeeding mothers. The majority of teachers are supportive of incorporating breastfeeding education in family and consumer sciences, sexual education, and health classes; however, time constraints and limited knowledge of infant feeding recommendations may be barriers to implementation of appropriate lesson plans.ConclusionsStudents generally support and are receptive to breastfeeding education; however, research on educator attitudes, knowledge, and experiences are necessary for appropriate implementation of breastfeeding education in varying school settings around the world.

The definition of a modern family is changing. In this case study, we describe the breastfeeding experience of a child receiving human milk from all 3 of his mothers: his 2 adoptive mothers, who induced lactation to nurse him, and his birth mother, who shared in his early feeding during the open adoption process and continued to pump and send milk to him for several months. We review the lactation protocol used by his adoptive mothers and the unique difficulties inherent in this multi-mother family dynamic. Both adoptive mothers successfully induced moderate milk production using a combination of hormonal birth control, domperidone, herbal supplements, and a schedule of breast pumping. However, because of the increased complexity of the immediate postpartum period and concerns with defining parental roles in a same-sex marriage, maintenance of milk production was difficult.

Background: International Board Certified Lactation Consultants (IBCLC) are healthcare professionals who are highly trained in lactation science; however, little is known about the efficacy of IBCLC-specific support on breastfeeding outcomes. Research aims: This systematic review and meta-analysis aimed to describe interventions containing direct support by IBCLCs during the postpartum period and to analyze the association between study characteristics and the prevalence breastfeeding outcomes. Methods: Electronic databases were searched for studies published between January 2001 and December 2018. Meta-analysis and meta-regression were performed on studies containing breastfeeding prevalence data at 3 or 6 months postpartum. Results: Seventeen interventions met all inclusion and exclusion criteria and eight research teams reported the prevalence of any or exclusive breastfeeding at 3 and/or 6 months. For any breastfeeding at 6 months, the pooled difference was 0.08 [0.04, 0.12] meaning we’d expect to observe 1 additional case of any breastfeeding at 6 months postpartum for every 12 women who received an IBCLC intervention, 95% CI [8, 25] rather than control conditions. Results differed depending on which outcome variable was used to measure breastfeeding and the timing of that measurement. Conclusions: Breastfeeding interventions that include IBCLC support in the postpartum period have potential for improving breastfeeding outcomes; however, when designing interventions, the timing and method of data collection for measures of breastfeeding are instrumental to study sensitivity and need to be based on the aims of the intervention itself.

A longer lifetime duration of breastfeeding may decrease the risk of breast cancer by reducing breast inflammation and mitigating inflammatory cytokine expression during postlactational involution. However, little is known about how the inflammatory cytokine profile in human breastmilk changes over time. To study temporal trends in breastmilk cytokine expression, we measured 80 human cytokines in the whey fraction of breastmilk samples from 15 mothers at 1, 4, 8, and 12 weeks postpartum. We used mixed models to identify temporal changes in cytokine expression and investigated parity status (multiparous vs. primiparous) as a potential confounder. Nine cytokines (monocyte chemoattractant protein-1, epithelial-derived neutrophil-activating protein-78, hepatocyte growth factor, insulin-like growth factor-binding protein-1, interleukin-16, interleukin-8, macrophage colony-stimulating factor, osteoprotegerin, and tissue inhibitor of metallopeptidase-2) had significantly decreased expression with increasing breastfeeding duration; all nine have known roles in breast involution, inflammation, and cancer and may serve as biomarkers of changing breast microenvironment. No cytokine significantly increased in level over the study period. Total protein concentration significantly decreased over time (p<0.0001), which may mediate the association between length of breastfeeding and inflammatory cytokine expression. Parity status did not confound temporal trends, but levels of several cytokines were significantly higher among multiparous versus primiparous women. Our results suggest that inflammatory cytokine expression during lactation is dynamic, and expressed milk may provide a noninvasive window into the extensive biological changes that occur in the postpartum breast.

Hypertension affects nearly 1 of 3 women and contributes to cardiovascular disease, the leading cause of death in the United States. Breastfeeding leads to metabolic changes that could reduce risks of hypertension. Hypertension disproportionately affects black women, but rates of breastfeeding among black women lag behind those in the general population. In the Black Women's Health Study (n = 59,001), we conducted a nested case-control analysis using unconditional logistic regression to estimate the association between breastfeeding and incident hypertension at ages 40-65 years using data collected from 1995 to 2011. Controls were frequency-matched 2:1 to 12,513 hypertensive women by age and questionnaire cycle. Overall, there was little evidence of association between ever breastfeeding and incident hypertension (odds ratio = 0.97, 95% confidence interval: 0.92, 1.02). However, age modified the relationship (P = 0.02): Breastfeeding was associated with reduced risk of hypertension at ages 40-49 years (odds ratio = 0.92, 95% confidence interval: 0.85, 0.99) but not at older ages. In addition, risk of hypertension at ages 40-49 years decreased with increasing duration of breastfeeding (P for trend = 0.08). Our results suggest that long-duration breastfeeding may reduce the risk of incident hypertension in middle age. Addressing breastfeeding as a potential preventative health behavior is particularly compelling because it is required for only a discrete period of time.