Behavior ofIn SituHuman Native Adipose TissueCD34+ Stromal/Progenitor Cells During Different Stages of Repair. Tissue‐ResidentCD34+ Stromal Cells as a Source of Myofibroblasts

Abstract

CD341 adipose stromal cells are scattered in the adipose tissue and found in the CD341 population of the stromal vascular fraction (SVF). This fraction includes adipose-derived stromal/stem/progenitor cells (ASCs), which have attracted considerable attention and show great promise for the future of regenerative medicine. Studies in this field have been undertaken mainly in vitro. In this work, however, we assessed the characteristics of human adipose tissue-resident CD341 stromal cells in normal conditions and when activated in vivo during inflammatory/repair processes at different stages of evolution. In normal adipose tissue, these cells showed a characteristic location (peri/paravascular and between adipocytes), a fusiform or stellate morphology, long and moniliform processes, and scarce organelles. During inflammatory/repair stages, native CD341 stromal cells increased in size, proliferated, developed numerous organelles of synthesis, lost CD34 expression, and differentiated into myofibroblasts (aSMA expression and typical ultrastructure). In double-stained sections, cells expressing both CD34 and aSMA were observed. CD34 expression correlated positively with a high proliferative capacity (Ki-67 expression). Conversely, CD34 expression was lost with successive mitoses and with increased numbers of macrophages in the granulation tissue. CD341 stromal cell behavior varied depending on proximity to (with myofibroblast differentiation) or remoteness from (with activated plump cells conserving CD34 expression) injury. In conclusion, our observations point to human adipose tissue-resident CD341 stromal cells as an important source of myofibroblasts during inflammatory/ repair processes. Moreover, stromal cell activation may occur with or without aSMA expression (with or without myofibroblast transformation) and with

Vasculogenic and angiogenic potential of adipose stromal vascular fraction cell populations in vitro

“…This phenomenon may be due to a variety of cell-cell signaling promoting cell migration and interaction leading to myofibroblastic contraction pulling groupings together (Supplemental Figure 1 ). Indeed, myofibroblasts as well as other contractile cells have been found in adipose-derived SVF (Diaz-Flores et al 2015 ). Cluster size does not seem to change between inhibitor and non-inhibitor groups; however, there is an increased trend in average size of clusters over 112 h across all groups (Fig.…”

New insights into the cellular makeup and progenitor potential of palatal connective tissues

“…One of the aims of this research was to trace the presence of a specific subset of cells in deCTGs and reCTGs ubiquitously distributed throughout the body that harbour the CD34 antigen, known as" CD34+ stromal fibroblastic/fibrocytic cells (CD34+ stromal cells, CD34+ fibroblasts, CD34 + fibrocytes, telocytes)" (Díaz‐Flores et al, ; Díaz‐Flores et al, ). More recently, the same authors (Díaz‐Flores et al, ) denominated these cells as CD34+ SC/TCs.…”

“…Cells with the same antigenic make‐up (CD34+, CD31−, αSMA−) were traced in the stromal fraction of the tissue samples, sending prolonged cytoplasmic processes in the tissue, which is in agreement with observations from other studies (Díaz‐Flores et al, ; Roman et al, ). Because CD34+ SC/TCs have differentiation capacities and provide scaffolding support for other cells (Díaz‐Flores et al, ), they could be considered important participants in wound healing and tissue repair. However, a deeper understanding of these phenomena and of the relationship between progenitors and stem cells is of great need (Bei, Wang, Yang, & Xiao, ).…”

The Aryl Hydrocarbon Receptor and Its Ligands Inhibit Myofibroblast Formation and Activation

“…48 Indeed, Smith and colleagues 49,50 found an increase in CD34 þ cells present in TED orbital tissue. It may be that circulating CD34 þ fibrocytes are trafficked to the orbit in TED and that these cells are a major source of scar-forming myofibroblasts.…”

“…It may be that circulating CD34 þ fibrocytes are trafficked to the orbit in TED and that these cells are a major source of scar-forming myofibroblasts. Diaz-Flores et al 48 found that CD34…”