The years 1960s and 1970s ushered in a new era in research when the transplantation of bone marrow into the kidney capsule by Dr. Friedenstein resulted in the division of the bone marrow cells and the formation of bone cells called osteoblasts. This suggested the presence of “stem cells” that form the bone along with the blood-forming cells. Later isolation and studies showed that these cells could also form chondrocytes (cartilage cells) and adipocytes (fat cells). The scientist Caplan gave these cells the name mesenchymal stem cells (MSCs). This name can be traced back to the word “mesenchyme” or the connective tissue forming cells of the embryo.
In his latest research, Caplan has called these cells “Medicinal Signaling Cells” as they can cause regeneration and healing after transplantation. The exact origin of MSCs is yet to be confirmed, according to researchers, Andrzejewska and team in Stem Cells (2019).
MSCs have been isolated from many tissues across a broad range of ages: foetal, young, adult, and elderly. The in vitro division and number of passages is more when using cells from adult tissues. Their sources include the bone marrow, peripheral blood, amniotic membranes, amniotic fluid, umbilical cord, Wharton jelly, umbilical cord blood, breast milk, fat (adipose) tissue, endometrium, dental pulp and menstrual blood.
MSCs can differentiate into hepatocytes, cartilage, bone, adipose, muscle cells, pancreas, β‐cells, and even neurons-cells of all the 3 germ layers: ectoderm, mesoderm, and endoderm. MSCs have shown the secretion of several immune factors interleukin-6, prostaglandin E2, transforming growth factor β, etc. this makes MSCs modulate the immune system: they decrease the levels of inflammatory T H1, lower the M1 phenotype of macrophages associated with inflammation and also lower B-cell antibody production.
The number of clinical trials doubles every few years with close to 1,000 registered items on the ClinicalTrials.gov website. An interesting example is the recovery of cardiac cells when MSCs were delivered to patients undergoing coronary artery bypass grafting. The research published in Circulation Research in 2014 by Karantalis and team described that the infracts decreased at 12 and 18 months while the heart function and stamina were also increased as seen by ejection fraction and 6 min walk test, respectively.
These make MSCs emerge as a powerful research area and industry given their advantages and effects. This can be an answer to improved care and quality of life in developing and developed countries to alter the face of medical care and treatment positively.
Caplan AI. Mesenchymal stem cells: Time to change the name! Stem Cells Translational Medicine 2017; 6: 1445– 1451.
Pittenger, M.F., Discher, D.E., Péault, B.M. , et al. Mesenchymal stem cell perspective: cell biology to clinical progress. npj Regenerative Medicine 4, 22 (2019).
Karantalis, V. et al. Autologous mesenchymal stem cells produce concordant improvements in regional function, tissue perfusion, and fibrotic burden when administered to patients undergoing coronary artery bypass grafting: the prospective randomized study of mesenchymal stem cell therapy in patients undergoing cardiac surgery (Prometheus) Trial. Circulation Research. 114, 1302–1310 (2014).