Stromal Cells

To analyze the effect of IL-10 overexpressed by APCs as observed in some SCID patients, we have expressed the human IL-10 cDNA under the control of the murine MHC class II promoter in transgenic mice. Similar to SCID patients, these mice presented a defect in T cell maturation characterized by a rapid thymic aplasia that started after birth. The blockage in T cell maturation was strictly restricted to TCR-alpha beta T cells as the absolute number of thymic dendritic, TCR-gamma delta and NK1.1 T cells were equivalent to control littermates. Crossing IL-10 transgenic mice with TCR transgenic mice or treatment with staphylococcal enterotoxin B showed that the defect was not related to the impairment of positive or negative selection. However, repopulating of IL-10 transgenic mouse-fetal thymic organ culture with different stages of triple negative T cells isolated from control mice showed that the blockage occurred specifically at the pre-T cell stage and was reverted by treatment with...

The stromal vascular fraction (SVF) is a heterogeneous population of stem/stromal cells isolated from perivascular and extracellular matrix (ECM) of adipose tissue complex (ATC). Administration of SVF holds a strong therapeutic potential for regenerative and wound healing medicine applications aimed at functional restoration of tissues damaged by injuries or chronic diseases. SVF is commonly divided into cellular stromal vascular fraction (cSVF) and tissue stromal vascular fraction (tSVF). Cellular SVF is obtained from ATC by collagenase digestion, incubation/isolation, and pellet-ized by centrifugation. Enzymatic disaggregation may alter the relevant biological characteristics of adipose tissue, while providing release of complex, multiattachment of cell-to-cell and cell-to-matrix, effectively eliminating the bioactive ECM and periadventitial attachments. In many countries , the isolation of cellular elements is considered as a "more than minimal" manipulation, and is most often limited to controlled clinical trials and subject to regulatory review. Several alternative , nonenzymatic methods of adipose tissue processing have been developed to obtain via minimal mechanical manipulation an autologous tSVF product intended for delivery, reducing the procedure duration, lowering production costs, decreasing regulatory burden, and shortening the translation into the clinical setting. Ideally, these procedures might allow for the integration of harvesting and processing of adipose tissue for ease of injection, in a single procedure utilizing a nonexpanded cellular product at the point of care, while permitting intraoperative autologous cellular and tissue-based therapies. Here, we review and discuss the options, advantages, and limitations of the major strategies alternative to enzymatic processing currently developed for minimal manipulation of adipose tissue. STEM CELLS TRANSLATIONAL MEDICINE 2019;8:1265–1271

This article reviews the main events of embryo-implantation and decidualization in rodents. In common laboratory rodents the embryo attaches to the uterine epithelial lining, usually on days 4 to 6 of pregnancy. A progressive degree of proximity between trophoblast and epithelium occurs until the epithelial cells undergo apoptosis and detach from the basement membrane. During the attachment stage, the spindle-shaped connective tissue cells that underlie the epithelium next to the embryos transform into polyhedral and closely packed decidual cells. Following the epithelial detachment and the breaching of the basement membrane the embryo is thus in direct contact with decidual cells. These cells accumulate organelles associated with synthesis of macromolecules, intermediate filaments, and eventually lipid droplets and glycogen. Another remarkable feature of decidual cells is the establishment of gap and adherens intercellular junctions. Differentiation of fibroblasts into decidual cells advances antimesometrially and mesometrially, creating in the endometrium several regions of cells with different morphology. The whole phenomenon of decidualization which is normally triggered by the embryo can be artificially induced in pseudopregnant or hormonally-prepared animals with the use of diverse stimuli. The uterine epithelium is probably responsible for the transduction of the initial stimulus. Prostaglandins have been shown to be important in the induction of decidualization. More recently other substances such as leukotrienes, platelet-activating factor (PAF), and transforming growth factor (TGF) have been thought to play a role in induction. Much evidence points to prostaglandin production by the decidual cells. New proteins such as a luteotropic factor, desmin, and other molecules were shown to be produced after rat stromal cells undergo decidual transformation. The extracellular matrix of the mouse decidua contains very thick collagen fibrils. Mouse decidual cells are also very active in phagocytosing the thick fibrils, contributing to the remodeling and involution of the decidua that accompanies embryonic growth. Radioautographic data indicates that mouse decidual cells produce and secrete collagen and sulfated proteoglycans. © 1993 Wiley-Liss, Inc.

The development of secondary lymphoid organs is initiated by crosstalk interactions between bone marrow-derived cells and stromal cells. Several of the molecules mediating this cell–cell communication are members of the Tumour Necrosis Factor (TNF) family of ligands and receptors that induce changes in the gene expression program through activation of different members of the Nuclear Factor kappa B (NF-кB) family of transcription factors. Engagement of TNF receptors by their specific ligands results in the activation of the canonical and non-canonical NF-кB pathways that ultimately induce the expression of cytokines, chemokines and cell adhesion molecules required for lymphorganogenesis, organization of specific areas in these organs and their long-term maintenance. Analysis of transgenic mice with impairments in these pathways have underlined the important function of different NF-кB family members, their cell specificity and requirement during lymphoid tissue organogenesis and helped to define some of their transcriptional targets.

Adipose tissue is accessible with minimally invasive procedures, is abundant, and is replenishable. It consists of a heterogeneous cell population including preadipocytes, mature adipocytes, fibroblasts, vascular smooth muscle cells, endothelial cells, resident macrophages, and cells composing the stromal vascular fraction. This fraction contains multipotent cells with the same mesenchymal origin and similar biological and immunological characteristics of bone marrow stroma. On the other hand, adipose-derived stromal cells are easier to harvest and culture in comparison to bone marrow-derived ones. The authors discuss the microenvironment where are the stem cells is the niche, adipose tissue, and adipose tissue-derived stromal cell transplant for the treatment of epithelial pathologies, wound healing, diabetic foot, and other disorders.

This study describes the culture conditions and the phenotypic features of different types of splenic cultures established from explants. Using the same culture technique it was possible to grow splenic explants from which monolayers of reticular origin, long-term haematopoietic cultures, and subcultures were obtained. The cultures were characterised by light and electron microscopy, cytochemical and immuno-cytochemical analyses, phagocytic activity and