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Stem Cells And Connective Tissues
Published in Miroslav Holub, Immunology of Nude Mice, 2020
The stromal cells of hematopoietic microenvironments play a crucial role in the control of stem cell differentiation and proliferation.16 The putative mesenchymal defect may affect the bone marrow stromal cells as well. There are small differences in the bone marrow cell differential counts between + / + and nu/nu mice;9,17 the only consistent distinction in various strains of mice is the extremely low lymphoid cell content in the bone marrow of nu/nu mice, in addition to an increased proportion of very primitive (“reticulum”) cells.9 Since, however, we have found the lowered stem cell count of the nu gene-bearing mice also in the fetal liver on gestation day 17,10 it seems that the migrating stem cells are affected indeed. Some quantitative reduction of the mesenchymal (mesodermal) cell supply may be sufficient to explain the defect both in the stem cell and stromal cell class: “… interactions between undifferentiated mesenchymal cells leading to regional specialization of inducing cells of the microenvironment may in turn be related to such parameters as cell-population density and aggregation, with further differentiation occurring once critical cell concentrations are achievd.”18 We have stressed in the discussion of thymic dysgenesis that such a lower-than-critical concentration of mesenchymal cells may be the causative agent of the deviation of the epithelial anlase development (Chapter 3, Section V).
Cells and Organs of the Immune System
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
The first step in the establishment of this hemopoietic environment is the formation of the medullary cavity. Primitive mesenchymal cells seed the cavity developing in the cartilage model of the bone. These mesenchymal precursors differentiate into stromal cells. These are a heterogeneous group of non-hemopoietic cells fixed within the marrow. Stromal cells are still undergoing analysis to permit useful classifications of function. Current systems of nomenclature rely on morphology and are inconsistent. Some of the types of stromal cells which have been described include: adipocytes, preadipocytes, fibroblasts, fibroblastoid, endothelioid, epithelioid, and smooth muscle-like. Arteries entering the bone break up into a subendosteal arteriovenous plexus which empties into the medullary sinusoids. Stromal cells and developing blood cells are in intimate contact within the intersinusoidal spaces.
Embryonic and Fetal Erythropoiesis
Published in Stephen A. Feig, Melvin H. Freedman, Clinical Disorders and Experimental Models of Erythropoietic Failure, 2019
D. Wade Clapp, Kevin M. Shannon
Aizawa and Tavassoli61,62 and Tavassoli and Minguell63 performed a series of studies examining a protein found on hematopoietic precursors that enabled those cells to “home” to bone marrow. Their data showed that both the adhesion of hematopoietic cells in vitro in long-term bone marrow cultures and the in vivo stem cell adherence to spleen can be blocked by synthetic proteins containing mannosyl and galactosyl lectins. They have determined that the homing protein is a 110,000 Mr lectinal though the complete structure of this molecule is still unknown.63 Lastly, Williams and co-workers64 showed that hematopoietic precursors interact with the carboxy-terminal heparin-binding domain of fibronectin in bone marrow stroma. Taken together, these results suggest that hematopoietic stem cells bind to stromal cells via several different receptors. It will be interesting in future studies to examine the ontogeny of the development of these different receptors.
A review of modern and Vedic practices on use of umbilical cord
Published in Journal of Obstetrics and Gynaecology, 2022
Samriti Khosla, Sarika Verma, Shalika Datta, Sandeep Sharma, Rajeshwar Sharma, Harpreet Walia, Hiteshwari Sabrol, Nishi Madan, Mamta Rani, Nitin Sood, Yashbeer Singh, Vikas Kahol, Puja Rattan, Pranjal Pachpore, Sapna Sethi, Lakhmir Singh, K. K. Raina, R. S. Yadav, Sumedha Dutta, Sisir Roy, K. Parthipan, G. Saidaiah, Rajeshwar Mukherjee, M. Srilatha, Vijeye Devuni, Minoo Aggarwal
Stromal cells are defined as the cell that can regenerate itself to produce more of its type and differentiate to produce specific type cells. Since 1950, stromal cells have been studied as a treatent for various life-threatening diseases through the procedure popularly known as haematopoietic stromal cell transplantation (HSCT) (Juric et al. 2016). There are two basic types of transplant: autologous and allogeneic. In autologous transplant, a person’s own stromal cells are used for therapy. In allogeneic transplant, a donor is used to provide stromal cells to the patient. For allogeneic transplants, tissue type of the donor and recipient should match (Liso et al. 2017). Although cell translation is effective against malignancies as well as for several non-malignant haematologic disorders and cancer therapy, many medical and ethical issues are associated with the most of the methods of stromal cell procurement.
Adipose-derived stromal/stem cells and extracellular vesicles for cancer therapy
Published in Expert Opinion on Biological Therapy, 2022
Gerhard Hamilton, Maryana Teufelsbauer
Mesenchymal stromal/cells (MSCs) are a heterogeneous subset of stromal stem cells that can be isolated from many adult tissues [1]. Although designated as stem cells, these adult cell types clearly differ from pluripotent embryonic stem cells and, therefore, are commonly summarized under the term ‘stromal’ cell population. MSCs can differentiate into cells of the mesodermal lineage, such as adipocytes, osteocytes, and chondrocytes, as well as cells of other embryonic lineages [2]. In 2005, the International Society of Cell Therapy defined mesenchymal stem cells as class of cells with plasticity, multi-directional differentiation potential, and expression of specific surface antigens such as CD73, CD90, and CD105 [3,4]. These cells are mainly located in perivascular regions of all tissue, including white adipose tissues [5]. MSCs can be harvested by relatively simple techniques and expanded in tissue culture to high cell numbers for possible therapeutic applications. After in vivo administration, MSCs migrate to injured tissues, where they can inhibit the release of pro-inflammatory cytokines and promote the survival of damaged cells. MSCs differentiate into local cell types of the damaged tissues and their ability to release chemokines, cytokines, and growth factors assist in tissue repair. However, treatments employing MSCs need to include characterized cell products, recording of intermediate parameters and surrogate endpoints with reports of the final patient outcome within regular trials in contrast to unregulated clinical applications [6].
Smoking effect on the ultrastructural properties of cultured lung myofibroblasts
Published in Ultrastructural Pathology, 2021
Siri Lehtonen, Ninni-Ingrid Nurmos, Henna M Karvonen, Elisa Lappi-Blanco, Terttu Harju, Magnus Sköld, Riitta Kaarteenaho
Even though the stromal cell and ECM modifications associated with smoking and COPD seem to be localization-specific, there are only a few studies comparing the properties of the stromal cells derived from different compartments of the lung. It has been shown that stromal cells derived and cultured from peripheral lung were more contractile than cells sampled from central lung.17 Furthermore, the stromal cells derived from peripheral lung of COPD patient were more contractile also containing more α-SMA than those cells derived from normal peripheral lung.17 TEM analysis has revealed that stromal cells cultured from central lung of smokers displayed fewer myofibroblastic features than cells derived from nonsmokers.13 These abovementioned features as mentioned in some other publications indicated that at least some of the diseases and localization specific properties of the stromal cells seem to be maintained during the culturing of these cells.18