Minor salivary gland mesenchymal stromal cells derived from patients with Sjӧgren's syndrome deploy intact immune plasticity

Background aimsMesenchymal stromal cells (MSCs) provide minor salivary glands (MSGs) with support and niche cells for epithelial glandular tissue. Little is known about resident MSG-derived MSCs (MSG-MSCs) in primary Sj?gren's syndrome (PSS). The authors’ objective is to define the immunobiology of endogenous PSS MSG-MSCs.MethodsUsing culture-adapted MSG-MSCs isolated from consenting PSS subjects (n = 13), the authors performed in vitro interrogation of PSS MSG-MSC immunobiology and global gene expression compared with controls. To this end, the authors performed phenotypic and immune functional analysis of indoleamine 2,3-dioxygenase (IDO), programmed death ligand 1 (PD-L1) and intercellular adhesion marker 1 (ICAM-1) before and after interferon γ (IFNγ) licensing as well as the effect of MSG-MSCs on T-cell proliferation. Considering the female predominance of PSS, the authors also addressed the influence of 17-β-estradiol on estrogen receptor α-positive-related MSC function.ResultsThe authors found that MSG-MSCs deployed normal immune regulatory functionality after IFNγ stimulation, as demonstrated by increased protein-level expression of IDO, PD-L1 and ICAM-1. The authors also found that MSG-MSCs suppressed T-cell proliferation in a dose-dependent manner independent of 17-β-estradiol exposure. Gene ontology and pathway analysis highlighted extracellular matrix deposition as a possible difference between PSS and control MSG-MSCs. MSG-MSCs demonstrated increased α-smooth muscle actin expression in PSS, indicating a partial myofibroblast-like adaptation.ConclusionsThese findings establish similar immune regulatory function of MSG-MSCs in both PSS and control patients, precluding intrinsic MSC immune regulatory defects in PSS. PSS MSG-MSCs show a partial imprinted myofibroblast-like phenotype that may arise in the setting of chronic inflammation, providing a plausible etiology for PSS-related glandular fibrosis.     

Pluripotent stem cell-derived mesenchymal stromal cells improve cardiac function and vascularity after myocardial infarction

Background aimsMesenchymal stromal cells (MSCs) have been shown to improve cardiac function after injury and are the subject of ongoing clinical trials. In this study, the authors tested the cardiac regenerative potential of an induced pluripotent stem cell-derived MSC (iPSC-MSC) population (Cymerus MSCs) in a rat model of myocardial ischemia-reperfusion (I/R). Furthermore, the authors compared this efficacy with bone marrow-derived MSCs (BM-MSCs), which are the predominant cell type in clinical trials.MethodsFour days after myocardial I/R injury, rats were randomly assigned to (i) a Cymerus MSC group (n = 15), (ii) a BM-MSC group (n = 15) or (iii) a vehicle control group (n = 14). For cell-treated animals, a total of 5 × 10⁶ cells were injected at three sites within the infarcted left ventricular (LV) wall.ResultsOne month after cell transplantation, Cymerus MSCs improved LV function (assessed by echocardiography) compared with vehicle and BM-MSCs. Interestingly, Cymerus MSCs enhanced angiogenesis without sustained engraftment or significant impact on infarct scar size. Suggesting safety, Cymerus MSCs had no effect on inducible tachycardia or the ventricular scar heterogeneity that provides a substrate for cardiac re-entrant circuits.ConclusionsThe authors here demonstrate that intra-myocardial administration of iPSC-MSCs (Cymerus MSCs) provide better therapeutic effects compared with conventional BM-MSCs in a rodent model of myocardial I/R. Because of its manufacturing scalability, iPSC-MSC therapy offers an exciting opportunity for an “off-the-shelf” stem cell therapy for cardiac repair.     

Systematic review and meta-analysis of randomized controlled trials of mesenchymal stromal cells to treat coronavirus disease 2019: is it too late?

Background aimsEvidence regarding the extent that mesenchymal stromal cells (MSCs) may improve clinical outcomes in patients with coronavirus disease 2019 (COVID-19) has been limited by marked inter-study heterogeneity, inconsistent product characterization and appreciable risk of bias (RoB). Given the evolution of treatment options and trajectory of the pandemic, an updated analysis of high-quality evidence from randomized controlled trials is needed for a timely and conclusive understanding of the effectiveness of MSCs.MethodsA systematic literature search through March 30, 2022, identified all English language, full-text randomized controlled trials examining the use of MSCs in the treatment of COVID-19.ResultsEight studies were identified (316 patients, 165 administered MSCs and 151 controls). Controls evolved significantly over time with a broad range of comparison treatments. All studies reported mortality at study endpoint. Random effects meta-analysis revealed that MSCs decreased relative risk of death (risk ratio, 0.63, 95% confidence interval, 0.42–0.94, P = 0.02, I² = 14%) with no significant difference in absolute risk of death. MSCs decreased length of hospital stay and C-reactive protein levels and increased odds of clinical improvement at study endpoint compared with controls. Rates of adverse events and severe adverse events were similar between MSC and control groups. Only two (25%) studies reported all four International Society for Cell & Gene Therapy criteria for MSC characterization. Included studies had low (n = 7) or some (n = 1) concerns regarding RoB.ConclusionsMSCs may reduce risk of death in patients with severe or critical COVID-19 and improve secondary clinical outcomes. Variable outcome reporting, inconsistent product characterization and variable control group treatments remain barriers to higher-quality evidence and may constrain clinical usage. A master protocol is proposed and appears necessary for accelerated translation of higher-quality evidence for future applications of MSC therapy.     

Impact of chronicity of injury on the proportion of mesenchymal stromal cells derived from anterior cruciate ligaments

Background aimsThe graft-healing potential of mesenchymal stromal cells (MSCs) derived from the remnants of ruptured anterior cruciate ligaments (ACLs) after ACL reconstruction may depend on the chronicity of the injury. The aim of this study was to assess the quantitative and phenotypic differences between MSCs isolated from ACL remnants in patients with (sub)acute and chronic tearing.MethodsTorn ACL remnants were harvested during ACL reconstruction from 41 patients, 24 with (sub)acute ACL (<6 months from injury to surgery) and 17 with chronic ACL (time interval >6 months) tears. MSCs isolated from these samples were assessed for quantitative and phenotypic differences, and the correlation between the proportion of MSCs and the chronicity of ACL tear was evaluated.ResultsAt passage 0, the mean proportion of MSCs (CD34⁻, CD44⁺, CD90⁺ and CD105⁺) was higher in (sub)acute than in chronic ACL tear samples (20.69% ± 7.82% versus 9.85% ± 8.01%, P < 0.001). At passages 1 and 2, however, MSC proportions did not differ significantly in the two groups. Time interval showed a negative correlation with MSC proportion only at passage 0 (r = −0.505, P < 0.001). The optimal cutoff value for time from injury to surgery yielding <10% freshly isolated ACL-MSCs, a percentage expected to have low tissue healing potential, was 23.5 months.ConclusionsThe proportion of freshly isolated MSCs was higher in samples from patients with (sub)acute tearing than in chronic ACL tearing and negatively correlated with the time interval between trauma and surgery.     

Is the subarachnoid administration of mesenchymal stromal cells a useful strategy to treat chronic brain damage?

Background aimsTraumatic brain injury (TBI) is a leading cause of mortality and morbidity worldwide. Developing effective protocols for the administration of mesenchymal stromal cells (MSCs) is a promising therapeutic strategy to treat TBI. It is important to develop alternatives to direct parenchymal injection at the injury site because direct injection is an expensive and invasive technique. Subarachnoid transplantation, a minimally invasive and low-risk procedure, may be an important and clinically applicable strategy. The aim of this study was to test the therapeutic effect of subarachnoid administration of MSCs on functional outcome 2 months after an experimental TBI in rats.MethodsTwo months after TBI, 30 female Wistar rats were divided into 3 groups (n = 10 in each group): sham, MSC (received 2 × 10⁶ MSCs) and saline (received only saline) groups. Neurological function, brain and spinal cords samples and cerebrospinal fluid were studied.ResultsNo significant differences were found in neurological evaluation and after histological analysis; differences in the expression of neurotrophins were present but were not statistically significant. MSCs survived in the host tissue, and some expressed neural markers.ConclusionsSimilar to direct parenchymal injections, transplanted MSCs survive, migrate to the injury cavity and differentiate into mature neural cell types for at least 6 months after engraftment. These results open the possibility that MSC administration through subarachnoid administration may be a treatment for the consequences of TBI. The transplantation technique and cell number should be adjusted to obtain functional outcome and neurotrophin production differences.     

Mesenchymal stem/stromal cell–based therapies for COVID-19: First iteration of a living systematic review and meta-analysis: MSCs and COVID-19

BackgroundMesenchymal stem/stromal cells (MSCs) and their secreted products are a promising therapy for COVID-19 given their immunomodulatory and tissue repair capabilities. Many small studies were launched at the onset of the pandemic, and repeated meta-analysis is critical to obtain timely and sufficient statistical power to determine efficacy.Methods and FindingsAll English-language published studies identified in our systematic search (up to February 3, 2021) examining the use of MSC-derived products to treat patients with COVID-19 were identified. Risk of bias (RoB) was assessed for all studies. Nine studies were identified (189 patients), four of which were controlled (93 patients). Three of the controlled studies reported on mortality (primary analysis) and were pooled through random-effects meta-analysis. MSCs decreased the risk of death at study endpoint compared with controls (risk ratio, 0.18; 95% confidence interval [CI], 0.04 to 0.74; P = .02; I² = 0%), although follow-up differed. Among secondary outcomes, interleukin-6 levels were most commonly reported and were decreased compared with controls (standardized mean difference, –0.69; 95% CI, –1.15 to –0.22; P = .004; I² = 0%) (n = 3 studies). Other outcomes were not reported consistently, and pooled estimates of effect were not performed. Substantial heterogeneity was observed between studies in terms of study design. Adherence to published ISCT criteria for MSC characterization was low. In two of nine studies, RoB analysis revealed a low to moderate risk of bias in controlled studies, and uncontrolled case series were of good (3 studies) or fair (2 studies) quality.ConclusionUse of MSCs to treat COVID-19 appears promising; however, few studies were identified, and potential risk of bias was detected in all studies. More controlled studies that report uniform clinical outcomes and use MSC products that meet standard ISCT criteria should be performed. Future iterations of our systematic search should refine estimates of efficacy and clarify potential adverse effects.     

Tolerogenic effect of mesenchymal stromal cells on gliadin-specific T lymphocytes in celiac disease

Background aimsCeliac disease is caused by a dysregulated immune response toward dietary gluten, whose only treatment is a lifelong gluten-free diet. We investigated the effects of mesenchymal stromal cells (MSCs) on gliadin-specific T cells, which are known to induce intestinal lesions, in view of a possible use as new therapy.MethodsBone marrow–derived MSCs and gliadin-specific T-cell lines were obtained from allogeneic donors and mucosal specimens of celiac patients, respectively. The immunosuppressant effect of MSCs was evaluated in terms of proliferative response and interferon (IFN)-γ production upon gliadin stimulation of long-term T-cell lines; the immunomodulant effect was assessed in terms of apoptotic rate, immunophenotype and cytokine profile of short-term T-cell lines generated in the presence of MSCs. Different MSC:T-cell ratios were applied, and statistics were performed as appropriate.ResultsMSCs inhibited both proliferative response and IFN-γ production of long-term T-cell lines in a dose-dependent manner while limiting the expansion of short-term T-cell lines by increasing the apoptotic rate. Moreover, a reduction of the CD4⁺ population and expansion of the regulatory FoxP3⁺ subset were found in T-cell lines cultured with MSCs, in which a significant decrease of interleukin (IL)-21, IFN-γ and IL-10 paralleled by an upregulation of transforming growth factor-β1, IL-6 and IL-8 were observed. Finally, an increase of the indoleamine 2,3-dioxygenase activity was found, possibly playing a key role in mediating these effects.ConclusionsMSCs exert potent immunomodulant effects on gliadin-specific T cells, which may be exploited for future therapeutic application in celiac disease.     

Current evidence on mesenchymal stem cell therapy for traumatic spinal cord injury: systematic review and meta-analysis

Background aimsThe authors aim to analyze the evidence in the literature regarding the efficacy and safety of mesenchymal stem cell (MSC) therapy in human subjects with traumatic spinal cord injury (SCI) and identify its potential role in the management of SCI.MethodsThe authors conducted independent and duplicate searches of electronic databases, including PubMed, Embase and the Cochrane Library, until May 2020 for studies analyzing the efficacy and safety of stem cell therapy for SCI. American Spine Injury Association (ASIA) impairment scale (AIS) grade improvement, ASIA sensorimotor score, activities of daily living score, residual urine volume, bladder function improvement, somatosensory evoked potential (SSEP) improvement and adverse reactions were the outcomes analyzed. Analysis was performed in R platform using OpenMeta[Analyst] software.ResultsNineteen studies involving 670 patients were included for analysis. On analysis, the intervention group showed statistically significant improvement in AIS grade (P < 0.001), ASIA sensory score (P < 0.017), light touch (P < 0.001), pinprick (P = 0.046), bladder function (P = 0.012), residual urine volume (P = 0.023) and SSEP (P = 0.002). However, no significant difference was noted in motor score (P = 0.193) or activities of daily living score (P = 0.161). Although the intervention group had a significant increase in complications (P < 0.001), no serious or permanent adverse events were reported. On subgroup analysis, low concentration of MSCs (<5 × 10⁷ cells) and initial AIS grade A presentation showed significantly better outcomes than their counterparts.ConclusionsThe authors’ analysis establishes the efficacy and safety of MSC transplantation in terms of improvement in AIS grade, ASIA sensory score, bladder function and electrophysiological parameters like SSEP compared with controls, without major adverse events. However, further research is needed to standardize dose, timing, route and source of MSCs used for transplantation.     

Incremental benefits of repeated mesenchymal stromal cell administration compared with solitary intervention after myocardial infarction

Background aimsTraditionally, stem cell therapy for myocardial infarction (MI) has been administered as a single treatment in the acute or subacute period after MI. These time intervals coincide with marked differences in the post-infarct myocardial environment, raising the prospect that repeat cell dosing could provide incremental benefit beyond a solitary intervention. This prospect was evaluated with the use of mesenchymal stromal cells (MSCs).MethodsThree groups of rats were studied. Single-therapy and dual-therapy groups received allogeneic, prospectively isolated MSCs (1 × 10⁶ cells) by trans-epicardial injection immediately after MI, with additional dosing 1 week later in the dual-therapy cohort. Control animals received cryopreservant solution only. Left ventricular (LV) dimensions and ejection fraction (EF) were assessed by cardiac magnetic resonance immediately before MI and at 1, 2 and 4 weeks after MI.ResultsImmediate MSC treatment attenuated early myocardial damage with EF of 35.3 ± 3.1% (dual group, n = 12) and 35.2 ± 2.2% (single group, n = 15) at 1 week after MI compared with 22.1 ± 1.9% in controls (n = 17, P < 0.01). In animals receiving a second dose of MSCs, EF increased to 40.7 ± 3.1% by week 4, which was significantly higher than in the single-therapy group (EF 35.9 ± 1.8%, P < 0.05). Dual MSC treatment was also associated with greater myocardial mass and arteriolar density, with trends toward reduced myocardial fibrosis. These incremental benefits were especially observed in remote (non-infarct) segments of LV myocardium.ConclusionsRepeated stem cell intervention in both the acute and the sub-acute period after MI provides additional improvement in ventricular function beyond solitary cell dosing, largely owing to beneficial changes remote to the area of infarction.     

Efficacy of mesenchymal stromal cells intraspinal transplantation for patients with different degrees of spinal cord injury: A systematic review and meta-analysis

Background aimsSeveral studies have reported that mesenchymal stromal cells (MSCs) may improve neurological functions in patients with spinal cord injury (SCI). In this study, we conducted a systematic review and meta-analysis to summarize the effects of MSC treatment on different degrees of severity of SCI.MethodsSystematic searching of studies reporting outcomes of MSCs on specific injury severities of patients with SCI was performed in The National Library of Medicine (MEDLINE), Embase and Cochrane for published articles up to the 6 July 2022. Two investigators independently reviewed the included studies and extracted the relevant data. The standardized mean differences of American Spinal Injury Association (ASIA) motor score, ASIA light touch scores, ASIA pinprick scores and the Barthel index between baseline and follow-ups were pooled.ResultsA total of eight studies were included. A large majority focused on patients with ASIA grade A classification. The pooled mean differences of ASIA motor scores, ASIA light touch scores, ASIA pinprick scores and the Barthel index were –2.78 (95% confidence interval [CI] –5.12 to –0.43, P = 0.02), –18.26 (95% CI –26.09 to –10.43, P < 0.01), –17.08 (95% CI –24.10 to –10.07, P < 0.01) and –4.37 (95% CI –10.96 to 2.22, P = 0.19), respectively.ConclusionsMSC transplantation was a significantly effective therapy for patients with SCI with ASIA grade A. In the future, further studies are warranted to confirm the potential beneficial effects of MSC therapy.     

A xeno-free culture method that enhances Wharton's jelly mesenchymal stromal cell culture efficiency over traditional animal serum–supplemented cultures

Background aimsMesenchymal stromal cell (MSC) transplantation holds great promise for use in medical therapies. Several key features of MSCs, including efficient cell growth, generation of sufficient cell numbers and safety, as determined by teratoma formation, make MSCs an ideal candidate for clinical use. However, MSCs derived under standard culture conditions, co-cultured with animal by-products, are inappropriate for therapy because of the risks of graft rejection and animal virus transmission to humans. Alternative serum sources have been sought for stem cell production.MethodsWe demonstrate for the first time that human serum from umbilical cord blood (hUCS) is an effective co-culture reagent for MSC production from Wharton's jelly MSCs (WJMSCs). Ten umbilical cords were used to generate parallel cultures of WJMSC lines under medium supplemented with hUCS and embryonic stem cell-qualified fetal bovine serum. The WJMSC lines from each medium were analyzed and compared with regard to cell line derivation, proliferation ability and characteristic stability.ResultsThe phenotypic characteristics of WJMSC derived under either medium showed no differences. WJMSC lines derived under hUCS medium displayed comparable primary culture cell outgrowth, lineage differentiation capacity and cell recovery after cryopreservation compared with supplementation with embryonic stem cell-qualified fetal bovine serum medium. However, superior cell proliferation rates and retention of in vitro propagation (>22 passages) were observed in WJMSC cultures supplemented with hUCS. Additionally, more robust population doubling times were observed in hUCS-supplemented cultures.ConclusionsWe conclude that hUCS is an efficient and effective serum source for animal product–free WJMSC line production and can generate MSC lines that may be appropriate for therapeutic use.     

Reliable isolation of human mesenchymal stromal cells from bone marrow biopsy specimens in patients after allogeneic hematopoietic cell transplantation

Isolation of mesenchymal stromal cells (MSCs) from pretreated, hematologic patients is challenging. Especially after allogeneic hematopoietic cell transplantation (HCT), standard protocols using bone marrow aspirates fail to reliably recover sufficient cell numbers. Because MSCs are considered to contribute to processes that mainly affect the outcome after transplantation, such as an efficient lymphohematopoietic recovery, extent of graft-versus-host disease as well as the occurrence of leukemic relapse, it is of great clinical relevance to investigate MSC function in this context. Previous studies showed that MSCs can be isolated by collagenase digestion of large bone fragments of hematologically healthy patients undergoing hip replacement or knee surgeries. We have now further developed this procedure for the isolation of MSCs from hematologic patients after allogeneic HCT by using trephine biopsy specimens obtained during routine examinations. Comparison of aspirates and trephine biopsy specimens from patients after allogeneic HCT revealed a significantly higher frequency of clonogenic MSCs (colony-forming unit–fibroblast [CFU-F]) in trephine biopsy specimens (mean, 289.8 ± standard deviation 322.5 CFU-F colonies/1 × 10⁶ total nucleated cells versus 4.2 ± 9.9; P < 0.0001). Subsequent expansion of functional MSCs isolated from trephine biopsy specimen was more robust and led to a significantly higher yield compared with control samples expanded from aspirates (median, 1.6 × 10⁶; range, 0–2.3 × 10⁷ P0 MSCs versus 5.4 × 10⁴; range, 0–8.9 × 10⁶; P < 0.0001). Using trephine biopsy specimens as MSC source facilitates the investigation of various clinical questions.     

Ex vivo-expanded highly pure ABCB5+ mesenchymal stromal cells as Good Manufacturing Practice-compliant autologous advanced therapy medicinal product for clinical use: process validation and first in-human data

Background aimMesenchymal stromal cells (MSCs) hold promise for the treatment of tissue damage and injury. However, MSCs comprise multiple subpopulations with diverse properties, which could explain inconsistent therapeutic outcomes seen among therapeutic attempts. Recently, the adenosine triphosphate-binding cassette transporter ABCB5 has been shown to identify a novel dermal immunomodulatory MSC subpopulation.MethodsThe authors have established a validated Good Manufacturing Practice (GMP)-compliant expansion and manufacturing process by which ABCB5⁺ MSCs can be isolated from skin tissue and processed to generate a highly functional homogeneous cell population manufactured as an advanced therapy medicinal product (ATMP). This product has been approved by the German competent regulatory authority to be tested in a clinical trial to treat therapy-resistant chronic venous ulcers.ResultsAs of now, 12 wounds in nine patients have been treated with 5 × 10⁵ autologous ABCB5⁺ MSCs per cm² wound area, eliciting a median wound size reduction of 63% (range, 32–100%) at 12 weeks and early relief of pain.ConclusionsThe authors describe here their GMP- and European Pharmacopoeia-compliant production and quality control process, report on a pre-clinical dose selection study and present the first in-human results. Together, these data substantiate the idea that ABCB5⁺ MSCs manufactured as ATMPs could deliver a clinically relevant wound closure strategy for patients with chronic therapy-resistant wounds.     

Infrapatellar fat pad-derived mesenchymal stromal cell product for treatment of knee osteoarthritis: a first-in-human study with evaluation of the potency marker

Background aimsInfrapatellar fat pad-derived mesenchymal stromal cells (IFP-MSCs) have not yet been used in a human clinical trial. In this open-label phase 1 study, patients with knee osteoarthritis (OA) received a single intra-articular injection of autologous IFP-MSCs. Safety was assessed through physical examination of the knee joint, vital signs, laboratory tests and adverse events. Efficacy was evaluated with regard to pain and function using questionnaires, x-ray and magnetic resonance imaging (MRI). Indoleamine-2,3-dioxygenase (IDO) expression in IFP-MSCs primed with interferon gamma was used as an in vitro potency measurement in investigating the correlations of clinical outcomes.MethodsTwelve patients with symptomatic knee OA were recruited. IFP adipose tissue was harvested from each patient's knee through surgical excision for IFP-MSC manufacturing. Cryopreserved IFP-MSCs (5 × 10⁷ cells) were injected into the knee joint immediately after thawing.ResultsNo significant adverse events were observed. Patients who received IFP-MSCs exhibited clinically significant pain and functional improvement at 48-week follow-up. The MRI Osteoarthritis Knee Score average was also significantly reduced from 100.2 before injection to 85.0 at 48 weeks after injection. The IDO expression of the primed IFP-MSCs of the 12 patients was correlated with clinical outcomes after injection.ConclusionsA single intra-articular injection of IFP-MSCs appears to be a safe therapy for treating knee OA and may improve disease symptoms. IDO measurement of primed IFP-MSCs has potential as a potency marker of MSC products for immunomodulatory therapy.     

Functional potentials of human hematopoietic progenitor cells are maintained by mesenchymal stromal cells and not impaired by plerixafor

Background aimsMesenchymal stromal cells (MSCs) resemble an essential component of the bone marrow niche for maintenance of stemness of hematopoietic progenitor cells (HPCs). Perturbation of the C-X-C chemokine receptor type 4 (CXCR4)/stromal cell-derived factor-1α (SDF-1α) axis by plerixafor (AMD3100) mobilizes HPCs from their niche; however, little is known about how plerixafor affects interaction of HPCs and MSCs in vitro.MethodsWe monitored cell division kinetics, surface expression of CD34 and CXCR4, migration behavior and colony-forming frequency of HPCs on co-culture with MSCs either with or without exposure to plerixafor.ResultsCo-culture with MSCs significantly accelerated cell division kinetics of HPCs. Despite this, the proportion of CD34⁺ cells was significantly increased on co-culture, whereas the expression of CXCR4 was reduced. In addition, co-culture with MSCs led to significantly higher colony-forming capacity and enhanced migration rate of HPCs compared with mono-culture conditions. The composition of MSC sub-populations—and conversely their hematopoiesis supportive functions—may be influenced by culture conditions. We compared the stromal function of MSCs isolated with three different culture media. Overall, the supporting potentials of these MSC preparations were quite similar. Perturbation by the CXCR4-antagonist plerixafor reduced the cell division kinetics of HPCs on co-culture with MSCs. However, the progenitor cell potential of the HPCs as reflected by colony-forming capacity was not affected by plerixafor.ConclusionsThese results support the notion that the CXCR4/SDF-1α axis is critical for HPC-MSC interaction with regard to migration, adhesion and regulation of proliferation but not for maintenance of primitive progenitor cells.     

Mesenchymal stromal cell injection protects against oxidative stress in Escherichia coli–induced acute lung injury in mice

Background aimsStem cells may be a promising therapy for acute respiratory distress syndrome. Recent in vivo and in vitro studies suggested that the mesenchymal stromal cells (MSCs) have anti-oxidative stress properties. We hypothesized that intravenous injection of bone marrow–derived mesenchymal stem cells (MSCs) could attenuate Escherichia coli–induced acute lung injury (ALI) in mice by controlling the oxidative stress status.MethodsEighty mice were randomly divided into four groups: group 1 (control group) received 25 μL of saline as a vehicle; group 2 contained E coli–induced ALI mice; group 3 included mice that received MSCs before induction of ALI; group 4 included mice that received MSCs after induction of ALI. Lung samples were isolated and assayed for oxidative stress variables and histopathologic analysis. Total anti-oxidant capacity was measured in broncho-alveolar lavage.ResultsPre- and post-injury MSC injection increased survival, reduced pulmonary edema and attenuated lung injuries in ALI mice. Histologically, MSCs exhibited a considerable degree of preservation of the pulmonary alveolar architecture. An increase of anti-oxidant enzyme activities and a decrease of myeloperoxidase activity and malondialdehyde levels in the MSC recipient groups versus the ALI group were found. Furthermore, the total anti-oxidant capacity and reduced glutathione levels were significantly increased in MSCs recipient groups versus the ALI group. Weak +ve inducible nitric oxide synthase immuno-expression in groups that received MSCs was detected. Pre-injury MSC injection showed better effects than did post-injury MSC injection.ConclusionsSystemic bone marrow–derived MSC injection was effective in modulating the oxidative stress status in E coli–induced acute lung injury in mice.     

Efficacy and safety of mesenchymal stromal cell treatment from related donors for patients with refractory aplastic anemia

Background aimsThis study evaluated the feasibility, safety and immunological effects of the intravenous administration of mesenchymal stromal cells (MSCs) from a related donor in patients with refractory aplastic anemia (AA).MethodsA mean of 6 × 10⁵/kg (range, 5.0–7.1 × 10⁵) MSCs were injected intravenously to 18 patients, including 14 patients with nonsevere AA and four patients with severe AA who were refractory to prior immunosuppressive treatment. The outcomes of patients treated with MSCs were evaluated and compared with a historic control cohort, including 18 patients with refractory AA.ResultsTwo patients had injection-related adverse events, including transient fever and headache. No major adverse events were reported during the follow-up period. An immunological analysis revealed an increased proportion of CD4⁺CD25⁺ FOXP3⁺regulatory T cells in peripheral mononuclear cells. Following up for 1 year, six of 18 patients (33.3%) achieved a complete response or a partial response to MSC treatment. In six patients, two achieved a complete response including a recovery of three hematopoietic cell lines after MSCs therapy at days 88 and 92, two patients achieved only a red cell recovery with hemoglobin levels >100 g/L at days 30 and 48 and two patients had only a platelet recovery with a platelet count of >60 × 10⁹/L at days 54 and 81. In the control cohort, only one patient (5.56%) achieved a partial response during the follow-up period.ConclusionsThe data from the present study suggest that treatment with MSCs from a related donor may be a promising therapeutic strategy for patients with refractory AA. The trial has been registered at ClinicalTrials.gov: identifier NCT01305694.     

Pancreas-derived mesenchymal stromal cells share immune response-modulating and angiogenic potential with bone marrow mesenchymal stromal cells and can be grown to therapeutic scale under Good Manufacturing Practice conditions

Background aimsMesenchymal stromal cells (MSCs) isolated from various tissues are under investigation as cellular therapeutics in a wide range of diseases. It is appreciated that the basic biological functions of MSCs vary depending on tissue source. However, in-depth comparative analyses between MSCs isolated from different tissue sources under Good Manufacturing Practice (GMP) conditions are lacking. Human clinical-grade low-purity islet (LPI) fractions are generated as a byproduct of islet isolation for transplantation. MSC isolates were derived from LPI fractions with the aim of performing a systematic, standardized comparative analysis of these cells with clinically relevant bone marrow-derived MSCs (BM MSCs).MethodsMSC isolates were derived from LPI fractions and expanded in platelet lysate-supplemented medium or in commercially available xenogeneic-free medium. Doubling rate, phenotype, differentiation potential, gene expression, protein production and immunomodulatory capacity of LPIs were compared with those of BM MSCs.ResultsMSCs can be readily derived in vitro from non-transplanted fractions resulting from islet cell processing (i.e., LPI MSCs). LPI MSCs grow stably in serum-free or platelet lysate-supplemented media and demonstrate in vitro self-renewal, as measured by colony-forming unit assay. LPI MSCs express patterns of chemokines and pro-regenerative factors similar to those of BM MSCs and, importantly, are equally able to attract immune cells in vitro and in vivo and suppress T-cell proliferation in vitro. Additionally, LPI MSCs can be expanded to therapeutically relevant doses at low passage under GMP conditions.ConclusionsLPI MSCs represent an alternative source of GMP MSCs with functions comparable to BM MSCs.     

Mesenchymal stromal cells alone or expressing interferon-β suppress pancreatic tumors in vivo,an effect countered by anti-inflammatory treatment

Background aimsBecause of the inflammatory nature and extensive stromal compartment in pancreatic tumors, we investigated the role of mesenchymal stromal cells (MSC) to engraft selectively in pancreatic carcinomas and serve as anti-tumor drug delivery vehicles to control pancreatic cancer progression.MethodsHuman pancreatic carcinoma cells, PANC-1, expressing renilla luciferase were orthotopically implanted into SCID mice and allowed to develop for 10 days. Firefly luciferase-transduced MSC or MSC expressing interferon (IFN)-β were then injected intraperitoneally weekly for 3 weeks. Mice were monitored by bioluminescent imaging for expression of renilla (PANC-1) and firefly (MSC) luciferase.ResultsMSC selectively homed to sites of primary and metastatic pancreatic tumors and inhibited tumor growth (P = 0.032). The production of IFN-β within the tumor site by MSC–IFN-β further suppressed tumor growth (P = 0.0000083). Prior studies indicated that MSC home to sites of inflammation; therefore, we sought to alter the tumor microenvironment through treatment with a potent anti-inflammatory agent. After treatment, inflammation-associated mediators were effectively down-regulated, including NFκB, vascular endothelial growth factor (VEGF) and interleukin (IL)-6 as well as chemokines involved in MSC migration (CCL3 and CCL25). Treatment with the anti-inflammatory agent CDDO-Me before and after MSC–IFN-β injections resulted in reduction of MSC in the tumors and reversed the positive effect of tumor inhibition by MSC–IFN-β alone (P = 0.041).ConclusionsThese results suggest that MSC exhibit innate anti-tumor effects against PANC-1 cells and can serve as delivery vehicles for IFN-β for the treatment of pancreatic cancer. However, these beneficial effects may be lost in therapies combining MSC with anti-inflammatory agents.