Mesenchymal stem cells reprogram host macrophages to attenuate obliterative bronchiolitis in murine orthotopic tracheal transplantation

Embryos assist morphogenesis of others through calcium and ATP signaling mechanisms in collective teratogen resistance

Information for organismal patterning can come from a variety of sources. We investigate the possibility that instructive influences for normal embryonic development are provided not only at the level of cells within the embryo, but also via interactions between embryos. To explore this, we challenge groups of embryos with disruptors of normal development while varying group size. Here, we show that Xenopus laevis embryos are much more sensitive to a diverse set of chemical and molecular-biological perturbations when allowed to develop alone or in small groups, than in large groups. Keeping per-embryo exposure constant, we find that increasing the number of exposed embryos in a cohort increases the rate of survival while incidence of defects decreases. This inter-embryo assistance effect is mediated by short-range diffusible signals and involves the P2 ATP receptor. Our data and computational model emphasize that morphogenesis is a collective phenomenon not only at the level of cells, but also of whole bodies, and that cohort size is a crucial variable in studies of ecotoxicology, teratogenesis, and developmental plasticity.

Evaluation of safety and efficacy of allogeneic adipose tissue-derived mesenchymal stem cells in pediatric bronchiolitis obliterans syndrome (BoS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT)

BACKGROUND

Allo-HSCT is a definite approach for the management of a wide variety of lethal and debilitating malignant and non-malignant disorders. However, its two main complications, acute and chronic graft-versus-host disease (GVHD), exert significant morbidities and mortalities. BoS, as a manifestation of chronic lung GVHD, is a gruesome complication of allo-HSCT, and for those with steroid-refractory disease, no approved second-line therapies exist. Mesenchymal stem cells (MSCs) exert anti-inflammatory and growth-promoting effects, and their administration against a wide range of inflammatory and neurologic disorders, as well as GVHD, has been associated with promising outcomes. However, literature on the safety and effectiveness of MSC therapy for BoS and pediatric cGVHD is scarce.

METHODS

We designed a single-arm trial to administer adipose tissue (AT)-derived MSCs to pediatric patients with refractory BoS after allo-HSCT. AT-MSCs from obese, otherwise healthy donors were cultured in an ISO class 1 clean room and injected into the antecubital vein of eligible patients with a dose of 1 × 106/kg. The primary endpoints included a complete or partial response to therapy [in terms of increased forced expiratory volume in one second (FEV1) values and steroid dose reduction] and its safety profile.

RESULTS

Four eligible patients with a median age of 6.5 years were enrolled in the study. Steroid-induced osteoporosis and myopathy were present in three cases. A partial response was evident in three cases after a single injection of AT-MSCs. The treatment was safe and tolerable, and no treatment-related adverse events were noted. Two patients developed manageable COVID-19 infections one and 4 months after AT-MSC injection. After a median follow-up duration of 19 months, all cases are still alive and have had no indications for lung transplantation.

CONCLUSIONS

AT-MSCs could be safely administered to our pediatric cases with BoS post-allo-HSCT. Considering their advanced stage of disease, their sub-optimal functional capacity due to steroid-induced complications, and COVID-19 infection post-treatment, we believe that AT-MSC therapy can have possible efficacy in the management of pediatric BoS. The conduction of further studies with larger sample sizes and more frequent injections is prudent for further optimization of AT-MSC therapy against BoS. Trial registration Iranian Registry of Clinical Trials (IRCT), IRCT20201202049568N2. Registered 22 February 2021, https://en.irct.ir/trial/53143 .

Mesenchymal Stromal Cell Therapy in Lung Transplantation

Lung transplantation is often the only viable treatment option for a patient with end-stage lung disease. Lung transplant results have improved substantially over time, but ischemia-reperfusion injury, primary graft dysfunction, acute rejection, and chronic lung allograft dysfunction (CLAD) continue to be significant problems. Mesenchymal stromal cells (MSC) are pluripotent cells that have anti-inflammatory and protective paracrine effects and may be beneficial in solid organ transplantation. Here, we review the experimental studies where MSCs have been used to protect the donor lung against ischemia-reperfusion injury and alloimmune responses, as well as the experimental and clinical studies using MSCs to prevent or treat CLAD. In addition, we outline ex vivo lung perfusion (EVLP) as an optimal platform for donor lung MSC delivery, as well as how the therapeutic potential of MSCs could be further leveraged with genetic engineering.

Key Role of Mesenchymal Stromal Cell Interaction with Macrophages in Promoting Repair of Lung Injury

Lung macrophages (Mφs) are essential for pulmonary innate immunity and host defense due to their dynamic polarization and phenotype shifts. Mesenchymal stromal cells (MSCs) have secretory, immunomodulatory, and tissue-reparative properties and have shown promise in acute and chronic inflammatory lung diseases and in COVID-19. Many beneficial effects of MSCs are mediated through their interaction with resident alveolar and pulmonary interstitial Mφs. Bidirectional MSC-Mφ communication is achieved through direct contact, soluble factor secretion/activation, and organelle transfer. The lung microenvironment facilitates MSC secretion of factors that result in Mφ polarization towards an immunosuppressive M2-like phenotype for the restoration of tissue homeostasis. M2-like Mφ in turn can affect the MSC immune regulatory function in MSC engraftment and tissue reparatory effects. This review article highlights the mechanisms of crosstalk between MSCs and Mφs and the potential role of their interaction in lung repair in inflammatory lung diseases.

Administration of Nrf-2-Modified Hair-Follicle MSCs Ameliorates DSS-Induced Ulcerative Colitis in Rats

Ulcerative colitis (UC) is a common chronic nonspecific intestinal inflammation of unknown etiology associated with a low cure rate and a high relapse rate. Hair follicle mesenchymal stem cells (HF-MSCs) are a class of pluripotent stem cells that have differentiation potential and strong proliferation ability. Nuclear factor red system related factor (Nrf-2) is a key factor in the oxidative stress response. Dextran sulfate sodium- (DSS-) induced rat UC models closely mimic human UC in terms of symptoms and histological changes. Animals were divided into five groups, including a healthy group and UC model rats treated with normal saline, Nrf-2, HF-MSCs, or Nrf-2-expressing HF-MSC group. Based on the expression of intestinal stem cells, inflammatory factors, anti-inflammatory factors, and disease activity index scores, Nrf-2-expressing HF-MSCs had the most obvious therapeutic effect under the same treatment regimen. This study provided a new potential clinical treatment option for ulcerative colitis.

Research Progress of Mesenchymal Stem Cell Therapy for Severe COVID-19

Corona virus disease 2019 (COVID-19) refers to a type of pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Sixty million confirmed cases have been reported worldwide until November 29, 2020. Unfortunately, the novel coronavirus is extremely contagious and the mortality rate of severe and critically ill patients is high. Thus, there is no definite and effective treatment in clinical practice except for antiviral therapy and supportive therapy. Mesenchymal stem cells (MSCs) are not only characterized by low immunogenicity and homing but also have anti-inflammatory and immunomodulation characteristics. Furthermore, they can inhibit the occurrence and development of a cytokine storm, inhibit lung injury, and exert antipulmonary fibrosis and antioxidative stress, therefore MSC therapy is expected to become one of the effective therapies to treat severe COVID-19. This article will review the possible mechanisms of MSCs in the treatment of severe COVID-19.

Postinfectious Bronchiolitis Obliterans in Children: Diagnostic Workup and Therapeutic Options: A Workshop Report

Bronchiolitis obliterans (BO) is a rare, chronic form of obstructive lung disease, often initiated with injury of the bronchiolar epithelium followed by an inflammatory response and progressive fibrosis of small airways resulting in nonuniform luminal obliteration or narrowing. The term BO comprises a group of diseases with different underlying etiologies, courses, and characteristics. Among the better recognized inciting stimuli leading to BO are airway pathogens such as adenovirus and mycoplasma, which, in a small percentage of infected children, will result in progressive fixed airflow obstruction, an entity referred to as postinfectious bronchiolitis obliterans (PIBO). The present knowledge on BO in general is reasonably well developed, in part because of the relatively high incidence in patients who have undergone lung transplantation or bone marrow transplant recipients who have had graft-versus-host disease in the posttransplant period. The cellular and molecular pathways involved in PIBO, while assumed to be similar, have not been adequately elucidated. Since 2016, an international consortium of experts with an interest in PIBO assembles on a regular basis in Geisenheim, Germany, to discuss key areas in PIBO which include diagnostic workup, treatment strategies, and research fields.

Cell therapy in the treatment of bronchiolitis obliterans in a murine model

OBJECTIVE

To evaluate the importance of stem cells derived from adipose tissue in reducing graft inflammation in a murine model of allogeneic heterotopic tracheal transplant.

METHODS

We performed a heterotopic tracheal allografting in dorsal subcutaneous pouch and systemically injected 5x105 mesenchymal stem cells derived from adipose tissue. The animals were divided into two groups according to the time of sacrifice: T7 and T21. We also carried out histological analysis and digital morphometry.

RESULTS

The T7 animals treated with cell therapy had median obstructed graft area of 0 versus 0.54 of controls (p = 0.635). The treated T21 subjects had median obstructed graft area of 0.25 versus 0 in controls (p = 0.041).

CONCLUSION

The systemically injected cell therapy in experimental murine model of bronchiolitis obliterans did not reduce the severity of the allograft inflammation in a statistically significant way in seven days; Conversely, in 21 days, it increased the allograft inflammatory process.

Mesenchymal Stromal Cell Therapy for Chronic Lung Allograft Dysfunction: Results of a First-in-Man Study

Chronic lung transplant rejection (termed chronic lung allograft dysfunction [CLAD]) is the main impediment to long‐term survival after lung transplantation. Bone marrow‐derived mesenchymal stromal cells (MSCs) represent an attractive cell therapy in inflammatory diseases, including organ rejection, given their relative immune privilege and immunosuppressive and tolerogenic properties. Preclinical studies in models of obliterative bronchiolitis and human trials in graft versus host disease and renal transplantation suggest potential efficacy in CLAD. The purpose of this phase 1, single‐arm study was to explore the feasibility and safety of intravenous delivery of allogeneic MSCs to patients with advanced CLAD. MSCs from unrelated donors were isolated from bone marrow, expanded and cryopreserved in a GMP‐compliant facility. Patients had deteriorating CLAD and were bronchiolitis obliterans (BOS) grade ≥ 2 or grade 1 with risk factors for rapid progression. MSCs (2 x 10⁶ cells per kilogram patient weight) were infused via a peripheral vein twice weekly for 2 weeks, with 52 weeks follow‐up. Ten Patients (5 male, 8 bilateral, median [interquartile range] age 40 [30–59] years, 3 BOS2, 7 BOS3) participated. MSC treatment was well tolerated with all patients receiving the full dosing schedule without any procedure‐related serious adverse events. The rate of decline in forced expiratory volume in one second slowed after the MSC infusions (120 ml/month preinfusion vs. 30 ml/month postinfusion, p = .08). Two patients died at 152 and 270 days post‐MSC treatment, both from progressive CLAD. In conclusion, infusion of allogeneic bone marrow‐derived MSCs is feasible and safe even in patients with advanced CLAD. Stem Cells Translational Medicine2017;6:1152–1157

Safety and therapeutic effect of mesenchymal stem cell infusion on moderate to severe ulcerative colitis

One of the primary targets of the clinical treatment of ulcerative colitis (UC) is to repair the damaged colonic mucosa. Mesenchymal stem cells (MSCs) have therapeutic potential in regenerative medicine due to their differentiation capacity and their secretion of numerous bioactive molecules. The present study describes a clinical trial (trial registration no. NCT01221428) investigating the safety and therapeutic effect of MSCs derived from human umbilical cord on moderate to severe UC. Thirty-four patients with UC were included in group I and treated with MSC infusion in addition to the base treatment, and thirty-six patients were in group II and treated with normal saline in addition to the base treatment. One month after therapy, 30/36 patients in group I showed good response, and diffuse and deep ulcer formation and severe inflammatory mucosa were improved markedly. During the follow up, the median Mayo score and histology score in group I were decreased while IBDQ scores were significantly improved compared with before treatment and group II (P<0.05). Compared with group II, there were no evident adverse reactions after MSC infusion in any of the patients in group I, and no chronic side effects or lingering effects appeared during the follow-up period. In conclusion, MSC infusion might be a useful and safe therapy for treating UC.

Phase II Multicenter, Randomized, Double-Blind Controlled Study of Efficacy and Safety of Umbilical Cord-Derived Mesenchymal Stromal Cells in the Prophylaxis of Chronic Graft-Versus-Host Disease After HLA-Haploidentical Stem-Cell Transplantation

PURPOSE

Although mesenchymal stromal cells (MSCs) possess immunomodulatory properties and exhibit promising efficacy against chronic graft-versus-host disease (cGVHD), little is known about the efficacy of MSCs in the prophylaxis of cGVHD after HLA-haploidentical hematopoietic stem-cell transplantation (HLA-haplo HSCT).

PATIENTS AND METHODS

In this multicenter, double-blind, randomized controlled trial, we investigated the incidence and severity of cGVHD among patients, and the changes in T, B, and natural killer (NK) cells after the repeated infusion of MSCs.

RESULTS

The 2-year cumulative incidence of cGVHD in the MSCs group was 27.4% (95% CI, 16.2% to 38.6%), compared with 49.0% (95% CI, 36.5% to 61.5%) in the non-MSCs control group (P = .021). Seven patients in the non-MSCs control group had severe lung cGVHD, but no patients in the MSCs group developed typical lung cGVHD (P = .047). After the MSC infusions, increasing memory B lymphocytes and regulatory T cells, as well as the ratio of type 1 T helper to type 2 T helper cells, were observed, whereas the number of NK cells decreased.

CONCLUSION

Our findings suggest that the repeated infusion of MSCs might inhibit cGVHD symptoms in patients after HLA-haplo HSCT, accompanied by changes in the numbers and subtypes of T, B, and NK cells, leading to the acquisition of immune tolerance.

The Critical Role of Induced CD4+ FoxP3+ Regulatory Cells in Suppression of Interleukin-17 Production and Attenuation of Mouse Orthotopic Lung Allograft Rejection

BACKGROUND

Lung transplantation is the only definitive therapy for many forms of end-stage lung disease. Studies have demonstrated the critical role of interleukin (IL)-17 in the development of lung rejection. Regulatory T cells (Tregs) are essential for the establishment and maintenance of immune tolerance.

METHODS

We established mouse orthotopic lung transplantation models to investigate the importance of IL-17 and IL-17-producing cell types in acute lung allograft rejection and the efficacy of the adoptive transfer of induced Tregs (iTregs) in attenuating pathologic lesions of lung allografts.

RESULTS

We found that the IL-17 produced by Th17 cells and γδ T cells might make the primary contributions to the progression of acute lung allograft rejection. Interleukin-17 deficiency decreased lung allograft lesions. Exogenous iTregs maintained their FoxP3 expression levels in lung allograft recipients. Induced Tregs therapy downregulated the expressions of Th17 and IL-17 γδ T cells and increased IL-10 production in the mouse orthotopic lung transplantation models. Moreover, the adoptive transfer of iTregs prolonged the survivals of the lung allografts and attenuated the progression of acute rejection.

CONCLUSION

These data suggested that the adoptive transfer of iTregs could suppress the Th17 cells and IL-17 γδ cells of the recipients, decrease the expression of IL-17, and attenuate the pathology of acute lung allograft rejection. Exogenous iTregs upregulated immunosuppressive factors, such as IL-10 and suppressed IL-17-producing cells, which was one of the pathways to play a role in protecting lung allografts.

A local application of mesenchymal stem cells and cyclosporine A attenuates immune response by a switch in macrophage phenotype

The immunosuppressive effects of systemically administered mesenchymal stem cells (MSCs) and immunosuppressive drugs have been well documented. We analysed the mechanisms underlying the therapeutic effect of MSCs applied locally in combination with non-specific immunosuppression in a mouse model of allogeneic skin transplantation. The MSC-seeded and cyclosporine A (CsA)-loaded nanofibre scaffolds were applied topically to skin allografts in a mouse model and the local immune response was assessed and characterized. MSCs migrated from the scaffold into the side of injury and were detected in the graft region and draining lymph nodes (DLNs). The numbers of graft-infiltrating macrophages and the production of nitric oxide (NO) were significantly decreased in recipients treated with MSCs and CsA, and this reduction correlated with impaired production of IFNγ in the graft and DLNs. In contrast, the proportion of alternatively activated macrophages (F4/80⁺ CD206⁺ cells) and the production of IL-10 by intragraft macrophages were significantly upregulated. The ability of MSCs to alter the phenotype of macrophages from the M1 type into an M2 population was confirmed in a co-culture system in vitro. We suggest that the topical application of MSCs in combination with CsA induces a switch in macrophages to a population with an alternatively activated 'healing' phenotype and producing elevated levels of IL-10. These alterations in macrophage phenotype and function could represent one of the mechanisms of immunosuppressive action of MSCs applied in combination with CsA. Copyright © 2015 John Wiley & Sons, Ltd.

MSC therapy attenuates obliterative bronchiolitis after murine bone marrow transplant

RATIONALE

Obliterative bronchiolitis (OB) is a significant cause of morbidity and mortality after lung transplant and hematopoietic cell transplant. Mesenchymal stromal cells (MSCs) have been shown to possess immunomodulatory properties in chronic inflammatory disease.

OBJECTIVE

Administration of MSCs was evaluated for the ability to ameliorate OB in mice using our established allogeneic bone marrow transplant (BMT) model.

METHODS

Mice were lethally conditioned and received allogeneic bone marrow without (BM) or with spleen cells (BMS), as a source of OB-causing T-cells. Cell therapy was started at 2 weeks post-transplant, or delayed to 4 weeks when mice developed airway injury, defined as increased airway resistance measured by pulmonary function test (PFT). BM-derived MSC or control cells [mouse pulmonary vein endothelial cells (PVECs) or lung fibroblasts (LFs)] were administered. Route of administration [intratracheally (IT) and IV] and frequency (every 1, 2 or 3 weeks) were compared. Mice were evaluated at 3 months post-BMT.

MEASUREMENTS AND MAIN RESULTS

No ectopic tissue formation was identified in any mice. When compared to BMS mice receiving control cells or no cells, those receiving MSCs showed improved resistance, compliance and inspiratory capacity. Interim PFT analysis showed no difference in route of administration. Improvements in PFTs were found regardless of dose frequency; but once per week worked best even when administration began late. Mice given MSC also had decreased peribronchiolar inflammation, lower levels of hydroxyproline (collagen) and higher frequencies of macrophages staining for the alternatively activated macrophage (AAM) marker CD206.

CONCLUSIONS

These results warrant study of MSCs as a potential management option for OB in lung transplant and BMT recipients.

Bone marrow-derived multipotent stromal cells attenuate inflammation in obliterative airway disease in mouse tracheal allografts

Obliterative bronchiolitis (OB) remains the most significant cause of death in long-term survival of lung transplantation. Using an established murine heterotopic tracheal allograft model, the effects of different routes of administration of bone marrow-derived multipotent stromal cells (MSCs) on the development of OB were evaluated. Tracheas from BALB/c mice were implanted into the subcutaneous tissue of major histocompatibility complex- (MHC-) disparate C57BL/6 mice. At the time of transplant, bone marrow-derived MSCs were administered either systemically or locally or via a combination of the two routes. The allografts were explanted at various time points after transplantation and were evaluated for epithelial integrity, inflammatory cell infiltration, fibrosis, and luminal obliteration. We found that the most effective route of bone marrow-derived MSC administration is the combination of systemic and local delivery. Treatment of recipient mice with MSCs suppressed neutrophil, macrophage, and T-cell infiltration and reduced fibrosis. These beneficial effects were observed despite lack of significant MSC epithelial engraftment or new epithelial cell generation. Our study suggests that optimal combination of systemic and local delivery of MSCs may ameliorate the development of obliterative airway disease through modulation of immune response.