Editorial: Amniotic Fluid Stem Cells and Their Secretomes as tools of regenerative medicine; Influence of Donor Characteristics on Standardization

Abstract

Amniotic fluid has emerged as a promising source of stem cells for tissue regeneration. Ethical concerns surrounding the isolation of amniotic fluid are minimal, as it can be safely collected during routine procedures such as second trimester amniocentesis, third trimester amnioreduction, or caesarean section at the end of gestation [1]. Amniotic fluid cells exhibit heterogeneity in morphology, in vitro, and in vivo characteristics, derived mainly from fetal tissues such as skin, respiratory, intestinal, and urinary tracts, as well as the amniotic membranes and connective tissues. Various cellular subpopulations exist within amniotic fluid, including epithelioid, "amniotic," and fibroblastic types, whose proportions vary according to gestational age. Amniotic fluid mesenchymal stem cells (AFMSC) are particularly promising due to their therapeutic potential which have been tested in different studies of muscle, cartilage, and bone defects [1]. The term "secretome" was initially introduced by Tjalsma et al., defining it "both the components of machineries for protein secretion and the native secreted proteins". This definition underwent further refinement by Hathout and Agrawal, who elaborated it to encompass factors secreted by cells, tissues, or organisms into the extracellular space under defined temporal and environmental conditions. Presently, it has been recognized that the secretome comprises not only soluble factors but also includes lipids and extracellular vesicles (EVs) containing vital molecules [2]. This novel perspective on cell-free-based therapies, which focuses on harnessing the secretome of cells, gained prominence inspiring the exploration of secretome-based applications across various domains of regenerative medicine. Due to concerns regarding potential adverse effects associated with cell-based therapies, including uncertainty regarding long-term recipient outcomes, there has been growing interest in the secretome produced by cells which have been attributed to their regenerative effects per se, particularly the secretome derived from Mesenchymal stem cells (MSCs). Utilization of MSC secretome offers several significant advantages, including the avoidance of invasive procedures for cell extraction, the ability to conduct pharmacological dose and safety assessments, ease of application, and the potential for manipulation of its composition [3]. Furthermore, MSC-derived secretome pivotal role in modulating innate and adaptive immune responses underlie their sought-after anti-inflammatory properties [3].