Comparative analysis on the anti-inflammatory/immune effect of mesenchymal stem cell therapy for the treatment of pulmonary arterial hypertension

Identification of novel membrane markers in circulating tumor cells of mesenchymal state in breast cancer

Cancer metastasis is a major cause of cancer-related deaths worldwide. The ability to detect and monitor circulating tumor cells (CTCs) offers a promising approach to early detection and management of metastasis. Although studies on epithelial markers for CTC detection are actively underway, the discovery of mesenchymal markers has not been studied sufficiently. In this study, we developed a new pipeline to identify membrane markers in CTCs of mesenchymal state in breast cancer based on expression profiles of the 310 CTC samples. From the total CTC samples, only CTC samples in the mesenchymal state were collected by employing hierarchical clustering. In samples belonging to the mesenchymal state, we calculated the correlation coefficients between 1995 membrane genes and ZEB2, which was determined as the key mesenchymal signature, allowing the 84 positively correlated genes. Furthermore, to ensure clinical significance, Kaplan-Meier analysis were performed on the 124 breast cancer patients, resulting in the 14 genes predicting prognosis. By exploring genes commonly identified in the both analyses, F11R and PTGIR were characterized as membrane markers in CTCs of mesenchymal state in breast cancer, which were evaluated by enriched terms, literature evidence, and relevant molecular pathways. We expect that the results will be helpful to more effective strategies for metastasis management.

Novel insights into the potential applications of stem cells in pulmonary hypertension therapy

Pulmonary hypertension (PH) refers to a group of deadly lung diseases characterized by vascular lesions in the microvasculature and a progressive increase in pulmonary vascular resistance. The prevalence of PH has increased over time. Currently, the treatment options available for PH patients have limited efficacy, and none of them can fundamentally reverse pulmonary vascular remodeling. Stem cells represent an ideal seed with proven efficacy in clinical studies focusing on liver, cardiovascular, and nerve diseases. Since the potential therapeutic effect of mesenchymal stem cells (MSCs) on PH was first reported in 2006, many studies have demonstrated the efficacy of stem cells in PH animal models and suggested that stem cells can help slow the deterioration of lung tissue. Existing PH treatment studies basically focus on the paracrine action of stem cells, including protein regulation, exosome pathway, and cell signaling; however, the specific mechanisms have not yet been clarified. Apoptotic and afunctional pulmonary microvascular endothelial cells (PMVECs) and alveolar epithelial cells (AECs) are two fundamental promoters of PH although they have not been extensively studied by researchers. This review mainly focuses on the supportive communication and interaction between PMVECs and AECs as well as the potential restorative effect of stem cells on their injury. In the future, more studies are needed to prove these effects and explore more radical cures for PH.

Stem cell therapy in pulmonary hypertension: current practice and future opportunities

Pulmonary hypertension (PH) is a progressive disease characterised by elevated pulmonary arterial pressure and right-sided heart failure. While conventional drug therapies, including prostacyclin analogues, endothelin receptor antagonists and phosphodiesterase type 5 inhibitors, have been shown to improve the haemodynamic abnormalities of patients with PH, the 5-year mortality rate remains high. Thus, novel therapies are urgently required to prolong the survival of patients with PH. Stem cell therapies, including mesenchymal stem cells, endothelial progenitor cells and induced pluripotent stem cells, have shown therapeutic potential for the treatment of PH and clinical trials on stem cell therapies for PH are ongoing. This review aims to present the latest preclinical achievements of stem cell therapies, focusing on the therapeutic effects of clinical trials and discussing the challenges and future perspectives of large-scale applications.

Early functional analysis on the pulmonary hemodynamic effects of Transamniotic Stem Cell Therapy (TRASCET) in the nitrofen model of congenital diaphragmatic hernia

PURPOSE

Transamniotic stem cell therapy (TRASCET) with mesenchymal stem cells (MSCs) has been shown to impact pulmonary vascular development and remodeling in experimental congenital diaphragmatic hernia (CDH), with secondary structural cardiac effects. We sought to determine whether TRASCET has any functional impact on term fetal pulmonary hemodynamics in the nitrofen model.

METHODS

Time-dated pregnant rat dams (n = 13) received nitrofen on gestational day 9 (E9) to induce fetal CDH. Fetuses (n = 155) were divided into three groups: untreated (n = 45), and two groups receiving volume-matched intra-amniotic injections on E17 of either saline (sham; n = 46), or a suspension of amniotic fluid-derived MSCs (afMSCs) (TRASCET; n = 64). Donor afMSCs were syngeneic, phenotyped by flow cytometry, and "primed" by exposure to interferon-gamma and interleukin-1beta prior to administration in vivo. At term (E21), fetuses underwent Doppler flow assessment at the mid-pulmonary artery and 4-chamber echocardiogram. Pulmonary vascular resistance was estimated by pulmonary artery acceleration time (PAAT), max velocity (MaxV) and velocity time integral (VTI). Cardiac function was assessed by global longitudinal strain (GLS) and ejection fraction (EF) using speckle analyses. Healthy fetuses (n = 11) served as additional controls. Statistical analysis was by the Mann-Whitney U test RESULTS: High resolution ultrasound data could be obtained from 8 to 13 fetuses per group. The PAAT and the PAAT normalized to cardiac cycle time were significantly improved by TRASCET compared to both untreated and sham-treated CDH (p = 0.004 to <0.001 in all pairwise comparisons). The flow profile sharpness (MaxV:VTI) was increased in untreated (p = 0.06) and sham (p = 0.01) groups but normalized by TRASCET (p<0.01). There was no difference in GLS between TRASCET and either the untreated or sham groups (p = 0.25 to p = 0.93).

CONCLUSION

Transamniotic stem cell therapy improves pulmonary vascular resistance in early term fetuses in the Nitrofen model of congenital diaphragmatic hernia. Further focus on the functional pulmonary hemodynamic impact of this therapy is justified.

LEVEL OF EVIDENCE

N/A (animal and laboratory study).

Mesenchymal Stem Cell Mechanisms of Action and Clinical Effects in Osteoarthritis: A Narrative Review

With the insufficient satisfaction rates and high cost of operative treatment for osteoarthritis (OA), alternatives have been sought. Furthermore, the inability of current medications to arrest disease progression has led to rapidly growing clinical research relating to mesenchymal stem cells (MSCs). The availability and function of MSCs vary according to tissue source. The three primary sources include the placenta, bone marrow, and adipose tissue, all of which offer excellent safety profiles. The primary mechanisms of action are trophic and immunomodulatory effects, which prevent the further degradation of joints. However, the function and degree to which benefits are observed vary significantly based on the exosomes secreted by MSCs. Paracrine and autocrine mechanisms prevent cell apoptosis and tissue fibrosis, initiate angiogenesis, and stimulate mitosis via growth factors. MSCs have even been shown to exhibit antimicrobial effects. Clinical results incorporating clinical scores and objective radiological imaging have been promising, but a lack of standardization in isolating MSCs prevents their incorporation in current guidelines.

MSC Transplantation Attenuates Inflammation, Prevents Endothelial Damage and Enhances the Angiogenic Potency of Endogenous MSCs in a Model of Pulmonary Arterial Hypertension

Purpose

Pulmonary arterial hypertension (PAH) is a progressive and fatal pulmonary vascular disease initiated by endothelial dysfunction. Mesenchymal stromal cells (MSCs) have been shown to ameliorate PAH in various rodent models; however, these models do not recapitulate all the histopathological alterations observed in human PAH. Broiler chickens (Gallus gallus) can develop PAH spontaneously with neointimal and plexogenic arteriopathy strikingly similar to that in human patients. Herein, we examined the protective effects of MSC transplantation on the development of PAH in this avian model.

Methods

Mixed-sex broilers at 15 d of age were received 2×10⁶ MSCs or PBS intravenously. One day later, birds were exposed to cool temperature with excessive salt in their drinking water to induce PAH. Cumulative morbidity from PAH and right-to-left ventricle ratio were recorded. Lung histologic features were evaluated for the presence of endothelial damage, endothelial proliferation and plexiform lesions. Expression of proinflammatory mediators and angiogenic factors in the lung was detected. Matrigel tube formation assay was performed to determine the angiogenic potential of endogenous MSCs.

Results

MSC administration reduced cumulative PAH morbidity and attenuated endothelial damage, plexiform lesions and production of inflammatory mediators in the lungs. No significant difference in the expression of paracrine angiogenic factors including VEGF-A and TGF-β was determined between groups, suggesting that they are not essential for the beneficial effect of MSC transplantation. Interestingly, the endogenous MSCs from birds receiving MSC transplantation demonstrated endothelial differentiatial capacity in vitro whereas those from the mock birds did not.

Conclusion

Our results support the therapeutic use of MSC transplantation for PAH treatment and suggest that exogenous MSCs produce beneficial effects through modulating inflammation and endogenous MSC-mediated vascular repair.

Stem Cell and Exosome Therapy in Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease that eventually causes right heart failure by remodeling pulmonary blood vessels. Based on the histopathological characteristics, PH is categorized into five subgroups. Rarely, a severe clinical entity is pulmonary arterial hypertension (PAH), subgroup 1. This disease process results in pulmonary vascular alterations through dysfunction of the pulmonary endothelium and disturbance of immune responses. Although medical treatments based on these pathophysiologic concepts have been applied for more than 30 years, PAH still cannot be cured. This review addresses the feasibility of and perspectives on stem cell therapy, including the role of exosomes in PAH.

Pulmonary hypertension is a rare and progressive illness with a devastating prognosis. Promising research efforts have advanced the understanding and recognition of the pathobiology of pulmonary hypertension. Despite remarkable achievements in terms of improving the survival rate, reducing disease progression, and enhancing quality of life, pulmonary arterial hypertension (PAH) is not completely curable. Therefore, an effective treatment strategy is still needed. Recently, many studies of the underlying molecular mechanisms and technological developments have led to new approaches and paradigms for PAH treatment. Management based on stem cells and related paracrine effects, epigenetic drugs and gene therapies has yielded prospective results for PAH treatment in preclinical research. Further trials are ongoing to optimize these important insights into clinical circumstances.

Bioinformatic exploration of the immune related molecular mechanism underlying pulmonary arterial hypertension

This study aimed to explore the molecular mechanisms related to immune and hub genes related to pulmonary arterial hypertension (PAH). The differentially expressed genes (DEGs) of GSE15197 were identified as filters with adjusted P value <0.05, and |Log2 fold change|> 1. Biofunctional and pathway enrichment annotation of DEGs indicated that immunity and inflammation may play an important role in the molecular mechanism of PAH. The CIBERSORT algorithm further analyzed the immune cell infiltration characteristics of the PAH and control samples. Subsequently, 16 hub genes were identified from DEGs using the least absolute shrinkage and selection operator (LASSO) algorithm. An immune related gene CX3CR1 was further selected from the intersection results of the 16 hub genes and the top 20 genes with the most adjacent nodes in the protein-protein interaction (PPI) network. GSE113439, GSE48149, and GSE33463 datasets were used to validate and proved CX3CR1 with a remarkable score of AUC to distinguish PAH samples caused by various reasons from the control group.

Application of adipose-derived stem cells in treating fibrosis

Fibrosis is the hyperactivation of fibroblasts that results in excessive accumulation of extracellular matrix, which is involved in numerous pathological changes and diseases. Adipose-derived stem cells (ASCs) are promising seed cells for regenerative medicine due to their bountiful source, low immunogenicity and lack of ethical issues. Their anti-fibrosis, immunomodulation, angiogenesis and other therapeutic effects have made them suitable for treating fibrosis-related diseases. Here, we review the literature on ASCs treating fibrosis, elaborate and discuss their mechanisms of action, changes in disease environment, ways to enhance therapeutic effects, as well as current preclinical and clinical studies, in order to provide a general picture of ASCs treating fibrotic diseases.

The Mandible Ameliorates Facial Allograft Rejection and Is Associated with the Development of Regulatory T Cells and Mixed Chimerism

Vascularized composite allografts contain various tissue components and possess relative antigenicity, eliciting different degrees of alloimmune responses. To investigate the strategies for achieving facial allograft tolerance, we established a mouse hemiface transplant model, including the skin, muscle, mandible, mucosa, and vessels. However, the immunomodulatory effects of the mandible on facial allografts remain unclear. To understand the effects of the mandible on facial allograft survival, we compared the diversities of different facial allograft-elicited alloimmunity between a facial osteomyocutaneous allograft (OMC), including skin, muscle, oral mucosa, and vessels, and especially the mandible, and a myocutaneous allograft (MC) including the skin, muscle, oral mucosa, and vessels, but not the mandible. The different facial allografts of a BALB/c donor were transplanted into a heterotopic neck defect on fully major histocompatibility complex-mismatched C57BL/6 mice. The allogeneic OMC (Allo-OMC) group exhibited significant prolongation of facial allograft survival compared to the allogeneic MC group, both in the presence and absence of FK506 immunosuppressive drugs. With the use of FK506 monotherapy (2 mg/kg) for 21 days, the allo-OMC group, including the mandible, showed prolongation of facial allograft survival of up to 65 days, whereas the myocutaneous allograft, without the mandible, only survived for 34 days. The Allo-OMC group also displayed decreased lymphocyte infiltration into the facial allograft. Both groups showed similar percentages of B cells, T cells, natural killer cells, macrophages, and dendritic cells in the blood, spleen, and lymph nodes. However, a decrease in pro-inflammatory T helper 1 cells and an increase in anti-inflammatory regulatory T cells were observed in the blood and lymph nodes of the Allo-OMC group. Significantly increased percentages of donor immune cells were also observed in three lymphoid organs of the Allo-OMC group, suggesting mixed chimerism induction. These results indicated that the mandible has the potential to induce anti-inflammatory effects and mixed chimerism for prolonging facial allograft survival. The immunomodulatory understanding of the mandible could contribute to reducing the use of immunosuppressive regimens in clinical face allotransplantation including the mandible.

Application of Exosomes-Derived Mesenchymal Stem Cells in Treatment of Fungal Diseases: From Basic to Clinical Sciences

Fungal diseases such as candidiasis are some of the deadliest diseases among immunocompromised patients. These fungi naturally exist on human skin and throughout the digestive system. When the microbiota balance becomes upset, these fungi become pathogenic and potentially lethal. At the pathogenesis of fungal diseases, host immune system response is diverse. At the early stages of fungal pathogenesis such as Candida albicans, it was shown that these fungi use the immune cells of the host body and cause malfunction the early induction of proinflammatory cytokines of the host body leading to a reduction in their numbers. However, at some stages of fungal diseases, the immune response is severe. Despite many treatments already being available, it seems that one of the best treatments could be an immune-stimulatory agent. Some of the subsets of MSCs and exosome-derived cells, as a cell-to-cell communicator agent, have many roles in the human body, including anti-inflammatory and immune-modulatory effects. However, the TLR4-primed and IL-17+ subsets of MSCs have been shown to have immune-stimulatory effects. These subsets of the MSCs produce pro-inflammatory cytokines and reduce immunosuppressive cytokines and chemokines. Thus, they could trigger inflammation and stop fungal pathogenesis. As some biological activities and molecules inherit elements of their exosomes from their maternal cells, the exosome-derived TLR4-primed and IL-17+ subsets of MSCs could be a good candidate for fighting against fungal diseases. The applications of exosomes in human diseases are well-known and expanding. It is time to investigate the exosomes application in fungal diseases. In this review, the probable role of exosomes in treating fungal diseases is explored.