Are pericytes stem cells?

"It all depends on how stringent your definition is of a stem cell, but I do believe they behave in a similar manner with related endpoints. Pericytes act as a plastic support cells with a primary goal of stabilizing vascular perfusion and function, much the same way that stem cells can adapt to different tissue needs to establish tissue homeostasis. " - Amanda Jo LeBlanc, Assistant Professor, University of Louisville
"As a pericyte purist, I would have previously said 'Pericytes are absolutely NOT stem cells." But recently seeing some live imaging of pericyte migration, I was surprised to see a subset of presumptive pericytes migrate off capillaries into the interstitium.  Do they assume a 'stem cell' phenotype?  We don't have concrete evidence, but I am not as resolute as I was before." - John C. Chappell, Assistant Professor, Virginia Tech Carilion Research Institute

"I think cell lineage-tracing studies in mice and novel dynamic imaging approaches are beginning to reveal that lots of different cells —pericytes included — possess previously unrecognized (trans) differentiation potential in vivo. This potential is likely heightened under conditions of injury and inflammation." - Shayn Peirce-Cottler, Professor, University of Virginia

"My simple answer is, no.  Pericytes have an established function within the vasculature and are essential in that function to the health of microvascular structures. However, pericytes do exhibit high plasticity with, at least, tri-liniage capabilities.  They have been demonstrated to express CD146, CD24 and Stro-1, and to transition into adipocytes, myofibroblasts and osteocytes.  In pathological states pericytes have been shown to migrate away from the vessel and contribute to the reactive microglia population. So, while we don't consider them to be stem cells as traditionally defined, they are certainly stem cell-like under the appropriate conditions.” - Anjelica Gonzales, Associate professor, Yale University

"I think pericytes have the potential to be stem cells, but I’m not sure to what extent they differentiate into and act as another cell type in vivo, particularly in non-disease states. Maybe our definition of stem cell is inadequate. We tend to think of cells in general as being either a differentiated cell or a stem cell, but maybe pericytes are stem cells incognito as differentiated cells. Perhaps they are never fully committed to differentiation and are on some continuum between these two states based on the priming conditions of the environment." - Jamie Mayo, Research Fellow, The University of Melbourne
"Pericytes are a jack of all trades, master of none. In the sense that, these cells are capable of mimicking the action of others cells within the vasculature without the need to differentiate." - Albert Gonzales, Postdoctoral Fellow, University of Vermont

"I think yes, but I do not know of definitive proof. It all depends on how you define a perciyte. I look at pericytes along capillaries under the microscope all day long and I do not know of any evidence to suggest that those cells transdifferentiate into another cell type. I will not be surprised, however, when we do discover that they can migrate off vessels, become interstitial cells, and differentiate into a nerve, endothelial cell, or another cell type. Maybe the question should be - Are pericytes macrophages?” - Lee Murfee, Associate Professor, Tulane University

"Given the challenges of identifying a definitive marker set for pericytes (markers often vary by tissue and/or are shared by other cells types) and the dynamic nature of the many different cell types within and around the microvascular niche, our group tends to use the "pericyte” label to refer to those non-endothelial and vascular smooth muscle cells associated with the microvessel that perform homeostatic activities (i.e. anti-inflammatory, pro-healing, microvessel stability, etc.) as opposed to a bona fide, single defined cell type.” - Jay Hoying, Professor, University of Louisville

"Using the broadest definition of a stem cell, which is defined as a cell that can self-renew and give rise to terminally differentiated cell(s) types, pericytes certainly have been demonstrated in multiple publications to fulfill these criteria. It is evident that the migration and "differentiation” of pericytes is markedly influenced by tissue injury, disease and inflammation. However, in the absence of definitive cell-specific markers and lineage tracing studies I think there is no absolute answer to this question at the present time.” - Bruce Bunnell, Professor, Tulane University

"I have yet to see evidence that pericytes can become any cell in the body – a pre-requisite for being classified as stem cells. That said, I believe they can acquire a new phenotype with different functions in special circumstances (such as when activated or in pathological conditions); which may make them be perceived as a different cell type altogether." - Sara S. Nunes de Vasconcelos, Assistant Professor, University of Toronto