nevertheless, currently research with pluripotent cells for regenerative medicine is still in basic or preclinical stages in the country. Collaborations of Brazilian research groups with international groups conducting clinical trials using pluripotent stem cell derived cells could shorten the gap between preclinical and clinical research with pluripotent stem cells in Brazil—and the country would contribute to the advancement of the field with the local infrastructure for clinical trials.
Stem Cell Industry
Despite all research in stem cells, until 2014 the Brazilian private sector had limited its investment in the field to stem cell banks. Following the creation of the first public Umbilical Cord and Placental Blood (UCPB) bank at the National Institute of Cancer (InCA) in 2001, several private UCPB banks were created, offering collection and storage of hematopoietic stem cells from newborns. Currently, some of these private banks also offer isolation and storage of mesenchymal stem cells from the umbilical vein and from adipose tissues, although no clinical use for these cells has been demonstrated yet. In 2004, the Ministry of Health created the BrasilCord Network, a public network of UCPB banks aimed to attend the need of hematopoietic stem cell donations not met by bone marrow registries. In 2014, BrasilCord had more than 17,000 UCPB units stored, of which 167 had already been used for transplants.
In the last 10 years, Brazil has fomented entrepreneurship and collaboration between academia and the private sector, providing funding opportunities from different government sources, including the National Bank for Economic and Social Development (BNDES), in the form of nonrefundable grants or low-interest loans. It is expected that these incentives will increase innovation within the industry, particularly in the field of regenerative medicine.
Lygia V. Pereira
University of São Paulo
See Also: Adult Stem Cells: Overview; Clinical Trials, Ethics of; ESC and iPSC Banking.
Further Readings
Fraga, Ana Maria, et al. “Establishment of a Brazilian Line of Human Embryonic Stem Cells in Defined Media: Implications for Cell Therapy in an Ethnically Diverse Population.” Cell Transplantation, v.20 (2010).
Inoue, Haruhisa, et al. “iPS Cells: A Game Changer for Future Medicine.” EMBO Journal, v.33 (2014).
Rede Nacional de Terapia Celular. http:/www.rntc.org.br (Accessed June 2014).
Tura, Bernardo, et al. “Multicenter Randomized Trial of Cell Therapy in Cardiopathies: MiHeart Study.” Trials, v.8 (2007).
Voltarelli, Julio Cezar, et al. “Autologous Nonmyeloablative Hematopoietic Stem Cell Transplantation in Newly Diagnosed Type 1 Diabetes Mellitus.” JAMA, v.297 (2007).
Breast: Cell Types Composing the Tissue
Breast: Cell Types Composing the Tissue
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Breast: Cell Types Composing the Tissue
This article provides a brief introduction to the cell types that compose human breast tissue. It focuses on the anatomy of the human breast, the major types of tissues and cells in breast tissue, and the role stem cells play in normal breast tissue and pathologies.
The human breast is located on the upper ventral region on the body and is a distinguishing feature of mammals. The breast is part of the skin and, therefore, part of the integumentary system. Breast tissue is composed of three main types of tissue: glandular tissue, connective tissue, and adipose tissue. The breast contains no muscle tissue. These components have various functions in the breast, which will be discussed further. The breast contains many lobes, which are composed of lobules. The lobules are composed of the aforementioned adipose tissue. These lobules give the breast its size and shape. All of these tissues are made up of various cell types that have different functions. The importance of stem cells in breast tissue is enormous. Breast cancer is the second leading cause of death for women in the United States, and it is a great concern among health care professionals. Therefore, understanding how stem cells operate is critical for how some breast pathologies are treated. The use of stem cells in regenerative medicine has become more realistic in the past several years.
Anatomy of Breast Tissue
The base of the breast is attached to the thoracic cavity by the pectoralis muscles. The space located between the pectoralis muscle and the breast is referred to as the retromammary space. This space is responsible for providing mobility to the breast. The next layer of tissue is a layer of fat called adipose tissue, which forms the majority of the breast. Then the suspensory Cooper’s ligaments extend from the superficial fascia, which is located on top of the layer of adipose tissue, into the breast to provide support. The lobules composed of adipose tissue form into a cone shape, which converge into the nipple. The areola, a dark pigmented area, surrounds the nipple. There are four major types of tissue in the human breast: epithelium, stroma, adipose tissue, and glandular tissue. The epithelium lines the surfaces and cavities throughout the body. The stroma is the connective tissue in the body. Adipose tissue makes up the majority of breast tissue and is composed of adipocytes (fat cells), preadipocytes, fibroblasts, endothelial cells, and various immune cells. There are two main types of adipose tissue: white adipose tissue and brown adipose tissue. The breast is also composed of glandular tissue. The breast is an apocrine gland that contains many sebaceous glands, which secrete sebum to waterproof the skin. Another apocrine function of the breast is to produce milk for infants.
Introduction to Stem Cells
A stem cell is an undifferentiated cell that is capable of giving rise to more cells of the same type indefinitely, and from which other types of cells can arise through differentiation. There are two main types of stem cells: pluripotent stem cells and multipotent stem cells. Pluripotent stem cells have the ability to differentiate into any of the three types of germ layers: endoderm, mesoderm, and ectoderm. Multipotent stem cells have the ability to differentiate into multiple, yet limited cell types. An example of this is a blood stem cell that can differentiate into lymphocytes, monocytes, or neutrophils but cannot differentiate into bone cells or heart cells.
Cell Types in Breast Tissue
There are three major epithelial cell types in breast tissue. The epithelial cell types are basal cells, luminal cells, and myoepithelial cells. The epithelium is composed of luminal cells and myoepithelial cells. These major cell types express different patterns of keratin that helps distinguish between them.
Luminal cells:
These inner cells are surrounded by myoepithelial cells, which help expel secretions and assist in the movement of saliva from salivary ducts. The luminal cells consist of differentiated cells and also many types of cells that are in between luminal cells and stem cells.
Basal cells:
These outer cells consist mostly of differentiated cells with several mammary stem cells.
Myoepithelial cells:
These
