Hypoxia-induced amniotic fluid stem cell secretome augments cardiomyocyte proliferation and enhances cardioprotective effects under hypoxic-ischemic conditions

MSC secretome from amniotic fluid halts IL-1β and TNF-α inflammation via the ERK/MAPK pathway, promoting cartilage regeneration in OA in vitro

Osteoarthritis (OA) is a degenerative disease that causes chronic pain and disability worldwide. This disease is mainly caused by IL-1β and TNF-α, which lead to cartilage degradation and inhibit the repair capacity of damaged cartilage. Recent studies have shown that amniotic fluid mesenchymal stem cells (AF-MSCs) secrete proteins that can effectively help in the treatment of cartilage damaged by OA. However, the underlying mechanism is still unclear. Therefore, the aim of this study was to investigate the effects and mechanisms behind the healing properties of the AF-MSC secretome (AFS-se) under OA conditions. This study involved growing chondrocyte progenitor cells (CPCs) and traumatized cartilage tissues in the presence of the cytokines IL-1β and TNF-α, which mimic OA conditions. AFS-se was then added to the culture medium to determine its effect on the CPCs and cartilage. Cell migration, endogenous cell outgrowth, the expression of chondrogenic and anabolic genes, and the mechanism of proteins in the NF-κB and MAPK signaling pathways were examined in this study. AFS-se inhibited the inflammatory effects of IL-1β and TNF-α by significantly reducing ERK phosphorylation in the MAPK signaling pathway and decreasing downstream proinflammatory COX2 products. The impaired CPCs recovered their ability to migrate, and endogenous CPCs in injured osteoarthritic cartilage were able to regrow in response to inflammatory stimuli. Additionally, the expression of anabolic genes such as Col I, Col II, and IGF1 was restored in defective CPCs. In conclusion, this study demonstrated that AFS-se has therapeutic effects on OA by inhibiting the inflammatory functions of IL-1β and TNF-α through protein phosphorylation in the MAPK pathway while also promoting the regenerative and self-repair functions of CPCs in traumatized cartilage.

Shenxiong glucose injection inhibits oxidative stress and apoptosis to ameliorate isoproterenol-induced myocardial ischemia in rats and improve the function of HUVECs exposed to CoCl2

Background: Shenxiong Glucose Injection (SGI) is a traditional Chinese medicine formula composed of ligustrazine hydrochloride and Danshen (Radix et rhizoma Salviae miltiorrhizae; Salvia miltiorrhiza Bunge, Lamiaceae). Our previous studies and others have shown that SGI has excellent therapeutic effects on myocardial ischemia (MI). However, the potential mechanisms of action have yet to be elucidated. This study aimed to explore the molecular mechanism of SGI in MI treatment. Methods: Sprague-Dawley rats were treated with isoproterenol (ISO) to establish the MI model. Electrocardiograms, hemodynamic parameters, echocardiograms, reactive oxygen species (ROS) levels, and serum concentrations of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) were analyzed to explore the protective effect of SGI on MI. In addition, a model of oxidative damage and apoptosis in human umbilical vein endothelial cells (HUVECs) was established using CoCl₂. Cell viability, Ca²⁺ concentration, mitochondrial membrane potential (MMP), apoptosis, intracellular ROS, and cell cycle parameters were detected in the HUVEC model. The expression of apoptosis-related proteins (Bcl-2, Caspase-3, PARP, cytoplasmic and mitochondrial Cyt-c and Bax, and p-ERK1/2) was determined by western blotting, and the expression of cleaved caspase-3 was analyzed by immunofluorescence. Results: SGI significantly reduced ROS production and serum concentrations of cTnI and cTnT, reversed ST-segment elevation, and attenuated the deterioration of left ventricular function in ISO-induced MI rats. In vitro, SGI treatment significantly inhibited intracellular ROS overexpression, Ca²⁺ influx, MMP disruption, and G2/M arrest in the cell cycle. Additionally, SGI treatment markedly upregulated the expression of anti-apoptotic protein Bcl-2 and downregulated the expression of pro-apoptotic proteins p-ERK1/2, mitochondrial Bax, cytoplasmic Cyt-c, cleaved caspase-3, and PARP. Conclusion: SGI could improve MI by inhibiting the oxidative stress and apoptosis signaling pathways. These findings provide evidence to explain the pharmacological action and underlying molecular mechanisms of SGI in the treatment of MI.

Amniotic fluid stem cell attenuated necrotizing enterocolitis progression by promoting Rspo3/AMPKα axis

R-spondin 3 (Rspo3) is involved in various cellular processes. The alteration of Rspo3 participates in the differentiation of intestinal epithelial cells which are the crucial effector cells during necrotizing enterocolitis (NEC) development. Amniotic fluid stem cells (AFSCs) were recently indicated as a potential approach for NEC therapy. This study aimed to illustrate the regulatory role and mechanism of Rspo3 in the pathogenesis of NEC and whether AFSCs therapy would impact NEC by mediating Rspo3. First, the alteration of Rspo3 was investigated in the serum and tissues of NEC patients, and an in vitro cell model induced by LPS. A gain-of-function assay was conducted to explore the function of Rspo3 in NEC. Through the analysis of adenosine 5'-monophosphate-activated protein kinase α (AMPKα) activation, the mechanism of Rspo3-mediated NEC progression was demonstrated. Finally, AFSCs were used to coculture human intestinal epithelial cells (HIECs) and the impacts on NEC development were also explored. The results found that Rspo3 was dramatically depressed during NEC progression and reversing Rspo3 expression ameliorated LPS-induced injury, inflammation, oxidative stress and tight junction dysregulation in HIECs. Besides, Rspo3 overexpression reversed AMPKα inactivation induced by NEC and an AMPKα inhibitor, Compound C, blocked the effect of Rspo3 overexpression on NEC. AFSCs treatment was beneficial for NEC therapy by restoring Rspo3 expression which was counteracted by exosome inhibitor. Generally, AFSCs attenuated NEC progression by promoting the Rspo3/AMPKα axis which might exert via the secretion of exosomes. Our conclusions might be valuable for NEC diagnosis and therapy.

Novel Approaches to Program Cells to Differentiate into Cardiomyocytes in Myocardial Regeneration

With heart failure (HF) being one of the leading causes of hospitalization and death worldwide, multiple stem cell therapies have been attempted to accelerate the regeneration of the infarct zone. Versatile strategies have emerged to establish the cell candidates of cardiomyocyte lineage for regenerative cardiology. This article illustrates critical insights into the emerging technologies, current approaches, and translational promises on the programming of diverse cell types for cardiac regeneration.

Conditioned media-integrated microneedles for hair regeneration through perifollicular angiogenesis

Androgenetic alopecia (AGA), the most prevalent type of hair loss in clinic, is induced partly by insufficient perifollicular vascularization. Here we designed a dissolvable microneedles (MNs) patch that was loaded with conditioned media (CM) derived from hypoxia-pretreated mesenchymal stem cells, which contained elevated HIF-1α. The CM-integrated MNs patch (designated as CM-MNs) can puncture the stratum corneum and deliver the pro-angiogenic factors directly into skin in a one-step and minimally invasive manner. Meanwhile, the administration of CM-MNs induced a certain mechanical stimulation on the skin, which can also promote neovascularization. With the combined effects of the pro-angiogenic factors in CM and the mechanical stimulation induced by MNs, CM-MNs successfully boosted perifollicular vascularization, and activated hair follicle stem cells, thereby inducing notably faster hair regeneration at a lower administration frequency on AGA mouse model compared with minoxidil. Furthermore, we proved that the inhibition of perifollicular angiogenesis restrained the awakening of hair follicle stem cells, elucidating the tight correlation between perifollicular angiogenesis and the activation of hair follicle stem cells. The innovative integration of CM and MNs holds great promise for clinical AGA treatment and indicates that boosting angiogenesis around hair follicles is an effective strategy against AGA.

Acellular human amniotic fluid protects the ischemic/reperfused rat myocardium

Amniotic products are potent immunomodulators utilized clinically to repair tissue injury. Little information exists regarding the potential of cell-free human amniotic fluid (hAF) to treat cardiovascular disease. Herein, we sought to determine the influence and efficacy of acellular hAF on myocardial ischemia/reperfusion injury. Processed hAF was obtained from volunteer donors at the time of elective caesarean section and manufactured using proprietary methods. Left anterior descending coronary artery ligation was performed on rats for 60 minutes. Thirty minutes after release and reperfusion, either saline or hAF was injected intramyocardially. Serial echocardiography revealed that compared to saline injected rats, hAF animals maintained their ejection fraction and did not adversely remodel through the 4-week period. This preserved ventricular function correlated with decreased infarct size, less fibrosis, and reduced expression of cytokines and infiltrating inflammatory cells. Comparative arrays of different donor hAF lots confirmed the presence of a wide array of immunomodulatory and host-defense proteins. The observed functional cardioprotection was furthermore evident when given intravenously and across multiple hAF donors. In conclusion, our data demonstrate, for the first time, the cardioprotective effect of acellular hAF on myocardial injury. These observations spanned across diverse donors and likely result from the mixture of a plethora of naturally produced cytokines, chemokines, and immune-modulating proteins rather than a single, defined mechanistic culprit. The ubiquitous availability of hAF as a cell-free solution further suggests its potential for widespread adoption as a therapy for myocardial ischemia/reperfusion injury.

Small Extracellular Vesicles from Human Amniotic Fluid Samples as Promising Theranostics

Since the first evidence that stem cells can provide pro-resolving effects via paracrine secretion of soluble factors, growing interest has been addressed to define the most ideal cell source for clinical translation. Leftover or clinical waste samples of human amniotic fluid obtained following prenatal screening, clinical intervention, or during scheduled caesarean section (C-section) delivery at term have been recently considered an appealing source of mesenchymal progenitors with peculiar regenerative capacity. Human amniotic fluid stem cells (hAFSC) have been demonstrated to support tissue recovery in several preclinical models of disease by exerting paracrine proliferative, anti-inflammatory and regenerative influence. Small extracellular vesicles (EVs) concentrated from the hAFSC secretome (the total soluble trophic factors secreted in the cell-conditioned medium, hAFSC-CM) recapitulate most of the beneficial cell effects. Independent studies in preclinical models of either adult disorders or severe diseases in newborns have suggested a regenerative role of hAFSC-EVs. EVs can be eventually concentrated from amniotic fluid (hAF) to offer useful prenatal information, as recently suggested. In this review, we focus on the most significant aspects of EVs obtained from either hAFSC and hAF and consider the current challenges for their clinical translation, including isolation, characterization and quantification methods.

Targeting cardiomyocyte proliferation as a key approach of promoting heart repair after injury

Cardiovascular diseases such as myocardial infarction (MI) is a major contributor to human mortality and morbidity. The mammalian adult heart almost loses its plasticity to appreciably regenerate new cardiomyocytes after injuries, such as MI and heart failure. The neonatal heart exhibits robust proliferative capacity when exposed to varying forms of myocardial damage. The ability of the neonatal heart to repair the injury and prevent pathological left ventricular remodeling leads to preserved or improved cardiac function. Therefore, promoting cardiomyocyte proliferation after injuries to reinitiate the process of cardiomyocyte regeneration, and suppress heart failure and other serious cardiovascular problems have become the primary goal of many researchers. Here, we review recent studies in this field and summarize the factors that act upon the proliferation of cardiomyocytes and cardiac repair after injury and discuss the new possibilities for potential clinical treatment strategies for cardiovascular diseases.

Insight into Hypoxia Stemness Control

Recently, the research on stemness and multilineage differentiation mechanisms has greatly increased its value due to the potential therapeutic impact of stem cell-based approaches. Stem cells modulate their self-renewing and differentiation capacities in response to endogenous and/or extrinsic factors that can control stem cell fate. One key factor controlling stem cell phenotype is oxygen (O₂). Several pieces of evidence demonstrated that the complexity of reproducing O₂ physiological tensions and gradients in culture is responsible for defective stem cell behavior in vitro and after transplantation. This evidence is still worsened by considering that stem cells are conventionally incubated under non-physiological air O₂ tension (21%). Therefore, the study of mechanisms and signaling activated at lower O₂ tension, such as those existing under native microenvironments (referred to as hypoxia), represent an effective strategy to define if O₂ is essential in preserving naïve stemness potential as well as in modulating their differentiation. Starting from this premise, the goal of the present review is to report the status of the art about the link existing between hypoxia and stemness providing insight into the factors/molecules involved, to design targeted strategies that, recapitulating naïve O₂ signals, enable towards the therapeutic use of stem cell for tissue engineering and regenerative medicine.

Metabolic Profile and Neurogenic Potential of Human Amniotic Fluid Stem Cells From Normal vs. Fetus-Affected Gestations

Human amniotic fluid stem cells (hAFSCs) possess some characteristics with mesenchymal stem cells (MSCs) and embryonic stem cells and have a broader differentiation potential compared to MSCs derived from other sources. Although hAFSCs are widely researched, their analysis mainly involves stem cells (SCs) obtained from normal, fetus-unaffected gestations. However, in clinical settings, knowledge about hAFSCs from normal gestations could be poorly translational, as hAFSCs from healthy and fetus-diseased gestations may differ in their differentiation and metabolic potential. Therefore, a more thorough investigation of hAFSCs derived from pathological gestations would provide researchers with the knowledge about the general characteristics of these cells that could be valuable for further scientific investigations and possible future clinical applicability. The goal of this study was to look into the neurogenic and metabolic potential of hAFSCs derived from diseased fetuses, when gestations were concomitant with polyhydramnios and compare them to hAFSCs derived from normal fetuses. Results demonstrated that these cells are similar in gene expression levels of stemness markers (SOX2, NANOG, LIN28A, etc.). However, they differ in expression of CD13, CD73, CD90, and CD105, as flow cytometry analysis revealed higher expression in hAFSCs from unaffected gestations. Furthermore, hAFSCs from “Normal” and “Pathology” groups were different in oxidative phosphorylation rate, as well as level of ATP and reactive oxygen species production. Although the secretion of neurotrophic factors BDNF and VEGF was of comparable degree, as evaluated with enzyme-linked immunosorbent assay (ELISA) test, hAFSCs from normal gestations were found to be more prone to neurogenic differentiation, compared to hAFSCs from polyhydramnios. Furthermore, hAFSCs from polyhydramnios were distinguished by higher secretion of pro-inflammatory cytokine TNFα, which was significantly downregulated in differentiated cells. Overall, these observations show that hAFSCs from pathological gestations with polyhydramnios differ in metabolic and inflammatory status and also possess lower neurogenic potential compared to hAFSCs from normal gestations. Therefore, further in vitro and in vivo studies are necessary to dissect the potential of hAFSCs from polyhydramnios in stem cell-based therapies. Future studies should also search for strategies that could improve the characteristics of hAFSCs derived from diseased fetuses in order for those cells to be successfully applied for regenerative medicine purposes.

Comprehensive Profiling of Secretome Formulations from Fetal- and Perinatal Human Amniotic Fluid Stem Cells

We previously reported that c-KIT+ human amniotic-fluid derived stem cells obtained from leftover samples of routine II trimester prenatal diagnosis (fetal hAFS) are endowed with regenerative paracrine potential driving pro-survival, anti-fibrotic and proliferative effects. hAFS may also be isolated from III trimester clinical waste samples during scheduled C-sections (perinatal hAFS), thus offering a more easily accessible alternative when compared to fetal hAFS. Nonetheless, little is known about the paracrine profile of perinatal hAFS. Here we provide a detailed characterization of the hAFS total secretome (i.e., the entirety of soluble paracrine factors released by cells in the conditioned medium, hAFS-CM) and the extracellular vesicles (hAFS-EVs) within it, from II trimester fetal- versus III trimester perinatal cells. Fetal- and perinatal hAFS were characterized and subject to hypoxic preconditioning to enhance their paracrine potential. hAFS-CM and hAFS-EV formulations were analyzed for protein and chemokine/cytokine content, and the EV cargo was further investigated by RNA sequencing. The phenotype of fetal- and perinatal hAFS, along with their corresponding secretome formulations, overlapped; yet, fetal hAFS showed immature oxidative phosphorylation activity when compared to perinatal ones. The profiling of their paracrine cargo revealed some differences according to gestational stage and hypoxic preconditioning. Both cell sources provided formulations enriched with neurotrophic, immunomodulatory, anti-fibrotic and endothelial stimulating factors, and the immature fetal hAFS secretome was defined by a more pronounced pro-vasculogenic, regenerative, pro-resolving and anti-aging profile. Small RNA profiling showed microRNA enrichment in both fetal- and perinatal hAFS-EV cargo, with a stably- expressed pro-resolving core as a reference molecular signature. Here we confirm that hAFS represents an appealing source of regenerative paracrine factors; the selection of either fetal or perinatal hAFS secretome formulations for future paracrine therapy should be evaluated considering the specific clinical scenario.