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Abstract While the COVID-19 outbreak and its complications are still under investigation, post-inflammatory pulmonary fibrosis (PF) has already been described as a long-term sequela of acute respiratory distress syndrome (ARDS) secondary to SARS-CoV2 infection. However, therapeutical strategies for patients with ARDS and PF are still limited and do not significantly extend lifespan. So far, lung transplantation remains the only definitive treatment for end-stage PF. Over the last years, numerous preclinical and clinical studies have shown that allogeneic mesenchymal stromal cells (MSCs) might represent a promising therapeutical approach in several lung disorders, and their potential for ARDS treatment and PF prevention has been investigated during the COVID-19 pandemic. From April 2020 to April 2022, we treated six adult patients with moderate COVID-19-related ARDS in a late proliferative stage with up to two same-dose infusions of third-party allogeneic bone marrow-derived MSCs (BM-MSCs), administered intravenously 15 days apart. No major adverse events were registered. Four patients completed the treatment and reached ICU discharge, while two received only one dose of MSCs due to multiorgan dysfunction syndrome (MODS) and subsequent death. All four survivors showed improved gas exchanges (PaO2/FiO2 ratio > 200), contrary to the others. Furthermore, LDH trends after MSCs significantly differed between survivors and the deceased. Although further investigations and shared protocols are still needed, the safety of MSC therapy has been recurrently shown, and its potential in treating ARDS and preventing PF might represent a new therapeutic strategy.

It has been demonstrated that mesenchymal stromal cells (MSCs) act by releasing bioactive molecules, among these are extracellular vesicles (EVs). The MSC-EVs are considered a convenient alternative to cell therapy, showing several functional characteristics of their origin cells. EVs can be collected from conditioned in vitro cultured MSCs. Different processes have been developed to induce in vitro EV release, and these approaches have been demonstrated to also influence MSC potentialities. This study aimed to investigate the effect of serum starvation on MSC characteristics. The morphology, phenotype, differentiation capacity, immunomodulatory ability, and metabolic state were maintained by MSCs cultured under starvation. To evaluate basic ultrastructural characteristics of cells and EVs, Transmission Electron Microscopy (TEM) analysis was performed on MSCs after 12, 24, and 48 h starvation, demonstrating that 24 h starvation was the best time for MSC structure preservation. Further studies are needed to support the hypothesis that MSCs after starvation could still be considered as therapeutic agents.

Abstract Background Lymphomatoid papulosis (LyP) is a rare condition in pediatrics; LyP histological type D has been reported in only 7 children. The differential diagnosis of LyP in the spectrum of lymphoid proliferation remains controversial. Case presentation A 6-year-old boy presented to Emergency Department with a 3-week history of an erythematous papulo-vesicular itchy eruption over the submandibular regions, trunk and extremities. History, symptoms and laboratory tests were unremarkable. SARS-CoV-2 antigen was negative. The clinical suspicion of pityriasis lichenoides et varioliformis acuta (PLEVA) was posed, and topical steroids were introduced. One week after, he returned with an extensive painful scaly papulo-erythematous rash, with some ulcerated and necrotic lesions, and fever; therefore the child was hospitalized. Biochemical results were within reference limits, except for high level of C-reactive protein, aspartate aminotransferase, alanine transaminase and bilirubin. Due to a persistently high fever, systemic corticosteroid treatment was administered, with a good clinical response and an improvement of the skin lesions. Anti-PVB-19 Immunoglobulin M was detected. Elevated levels of IL-6, IL-10 and IFN-γ were also recorded. Five days post-admission, most of the lesions had cleared, and the child was discharged. Methotrexate was started, with a positive response. At skin biopsy a “PLEVA-like” pattern was apparent, with a dense, wedge shaped lymphoid infiltrate featuring epidermotropism and morphologically comprising pleomorphic and blastic cells. The pattern of infiltration was highlighted by immunohistochemical stains, which prove the process to feature a CD8+/CD30 + phenotype, the latter being intense on larger cells, with antigenic loss. Polymerase chain reaction for T-cell receptor gamma (TCRG) chain clonality assessment documented a monoclonal peak. A diagnosis of LyP type D was favored. Conclusion The reported case encompasses most of the critical features of two separated entities—PLEVA and LyP—thus providing further support to the concept of them representing declinations within a sole spectrum of disease. Studying the role of infectious agents as trigger potential in lymphoproliferative cutaneous disorders and detecting novel markers of disease, such as cytokines, could have a crucial impact on pathogenic disease mechanisms and perspective therapies.

Objectives: Vaccination is the best strategy against COVID-19. We aimed to determine antibodies against SARS-CoV-2 in breastmilk and serum of mothers vaccinated with the mRNA vaccine. Methods: This prospective study included 18 lactating women vaccinated with the BNT162b2 vaccine. Serum and breastmilk were collected before the first dose (T0), at the second dose (T1), 3 weeks after the second dose (T2), and 6 months after the first dose (T3). Serum anti-SARS-CoV-2 Spike (S) Immunoglobulin G (IgG) and Immunoglobulin A (IgA) were measured using a semi-quantitative enzyme-linked immunosorbent assay (ELISA) and secretory antibody (s) IgG and IgA in breastmilk using quantitative analysis. Results: We detected serum anti-S IgG and IgA in all women after vaccination. Specific IgG and IgA were higher at T1, T2, and T3 compared with T0 (P

Mesenchymal Stromal Cell (MSC) clinical applications have been widely reported and their therapeutic potential has been documented in several diseases. MSCs can be isolated from several human tissues and easily expanded in vitro, they are able to differentiate in a variety of cell lineages, and they are known to interact with most immunological cells, showing immunosuppressive and tissue repair properties. Their therapeutic efficacy is closely associated with the release of bioactive molecules, namely Extracellular Vesicles (EVs), effective as their parental cells. EVs isolated from MSCs act by fusing with target cell membrane and releasing their content, showing a great potential for the treatment of injured tissues and organs, and for the modulation of the host immune system. EV-based therapies provide, as major advantages, the possibility to cross the epithelium and blood barrier and their activity is not influenced by the surrounding environment. In the present review, we deal with pre-clinical reports and clinical trials to provide data in support of MSC and EV clinical efficacy with particular focus on neonatal and pediatric diseases. Considering pre-clinical and clinical data so far available, it is likely that cell-based and cell-free therapies could become an important therapeutic approach for the treatment of several pediatric diseases.

Mesenchymal stromal cells (MSCs) play an important role in the field of regenerative medicine thanks to their immunomodulatory properties and their ability to secrete paracrine factors. The use of MSCs has also been tested in children with congenital lung diseases inducing fibrosis and a decrease in lung function. Congenital malformations of the pulmonary airways (CPAM) are the most frequently encountered lung lesion that results from defects in early development of airways. Despite the beneficial properties of MSCs, interventions aimed at improving the outcome of cell therapy are needed. Hypoxia may be an approach aimed to ameliorate the therapeutic potential of MSCs. In this regard, we evaluated the transcriptomic profile of MSCs collected from pediatric patients with CPAM, analyzing similarities and differences between healthy tissue (MSCs-lung) and cystic tissue (MSCs-CPAM) both in normoxia and in cells preconditioned with hypoxia (0.2%) for 24 h. Study results showed that hypoxia induces cell cycle activation, increasing in such a way the cell proliferation ability, and enhancing cell anaerobic metabolism in both MSCs-lung and MSCs-CPAM-lung. Additionally, hypoxia downregulated several pro-apoptotic genes preserving MSCs from apoptosis and, at the same time, improving their viability in both comparisons. Finally, data obtained indicates that hypoxia leads to a greater expression of genes involved in the regulation of the cytoskeleton in MSCs-lung than MSCs-CPAM.

Congenital anomalies may have an increased risk of noncommunicable diseases (NCDs) We performed a clinical exome analysis in an infant affected by “Vertebral, Anorectal, Cardiac, Tracheoesophageal, Genitourinary, and Limb” (VACTERL) malformation association to identify potential biomarkers that may be helpful for preventing malignancy risk or other chronic processes. Among the variants, six variants that may be linked with VACTERL were identified in the exome analysis. The variants c.501G>C on OLR1 and c.-8C>G on PSMA6 were previously associated with myocardial infarction. The variants c.1936A>G on AKAP10 and c.575A>G on PON1 are linked to defects in cardiac conduction and artery disease, respectively. Alterations in metabolism were also suggested by the variants c.860G>A on EPHX2 and c.214C>A on GHRL. In addition, three variants associated with colon cancer were discovered. Specifically, the reported variants were c.723G>A on CCND1 and c.91T>A on AURKA proto-oncogenes as well as c.827A>C in the tumor suppressor PTPRJ. A further inspection identified 15 rare variants carried by cancer genes. Specifically, these mutations are located on five tumor suppressors (SDHA, RB1CC1, PTCH1, DMBT1, BCR) and eight proto-oncogenes (MERTK, CSF1R, MYB, ROS1, PCM1, FGFR2, MYH11, BRCC3) and have an allele frequency lower than 0.01 in the Genome Aggregation Database (GnomAD). We observed that the cardiac and metabolic phenotypic traits are linked with the genotype of the patient. In addition, the risk of developing neoplasia cannot be excluded a priori. Long-term surgical issues of patients with VATER syndrome could benefit from the clinical exome sequencing of a personalized risk assessment for the appearance of further disease in pubertal timing and adult age.

In the next-generation sequencing era, RT-qPCR is still widely employed to quantify levels of nucleic acids of interest due to its popularity, versatility, and limited costs. The measurement of transcriptional levels through RT-qPCR critically depends on reference genes used for normalization. Here, we devised a strategy to select appropriate reference genes for a specific clinical/experimental setting based on publicly available transcriptomic datasets and a pipeline for RT-qPCR assay design and validation. As a proof-of-principle, we applied this strategy to identify and validate reference genes for transcriptional studies of bone-marrow plasma cells from patients with AL amyloidosis. We performed a systematic review of published literature to compile a list of 163 candidate reference genes for RT-qPCR experiments employing human samples. Next, we interrogated the Gene Expression Omnibus to assess expression levels of these genes in published transcriptomic studies on bone-marrow plasma cells from patients with different plasma cell dyscrasias and identified the most stably expressed genes as candidate normalizing genes. Experimental validation on bone-marrow plasma cells showed the superiority of candidate reference genes identified through this strategy over commonly employed “housekeeping” genes. The strategy presented here may apply to other clinical and experimental settings for which publicly available transcriptomic datasets are available.

The explanation for cancer recurrence still remains to be fully elucidated. Moreover, tumor dormancy, which is a process whereby cells enter reversible G0 cell cycle arrest, appears to be a critical step in this phenomenon. We evaluated the cell cycle proliferation pattern in pediatric tumor-derived mesenchymal stromal cells (MSCs), in order to provide a better understanding of the complex mechanisms underlying cancer dormancy. Specimens were obtained from 14 pediatric patients diagnosed with solid tumors and submitted to surgery. Morphology, phenotype, differentiation, immunological capacity, and proliferative growth of tumor MSCs were studied. Flow cytometric analysis was performed to evaluate the cell percentage of each cell cycle phase. Healthy donor bone marrow-derived mesenchymal stromal cells (BM-MSCs) were employed as controls. It was noted that the DNA profile of proliferating BM-MSC was different from that of tumor MSCs. All BM-MSCs expressed the typical DNA profile of proliferating cells, while in all tumor MSC samples, ≥70% of the cells were detected in the G0/G1 phase. In particular, seven tumor MSC samples displayed intermediate cell cycle behavior, and the other seven tumor MSC samples exhibited a slow cell cycle. The increased number of tumor MSCs in the G0–G1 phase compared with BM-MSCs supports a role for quiescent MSCs in tumor dormancy regulation. Understanding the mechanisms that promote dormant cell cycle arrest is essential in identifying predictive markers of recurrence and to promote a dedicated surgical planning.

Mesenchymal stromal cells (MSCs) have been proposed as a new therapeutic strategy to treat congenital and acquired respiratory system diseases. We describe a case report of an 18-month-old male patient with progressive chronic respiratory failure, associated with mutations of the surfactant protein C gene (SFTPC) due to c.289G > T variant p.Gly97Ser (rs927644577) and c.176A > G variant (p.His59Arg), submitted to repeated intravenous infusions of allogeneic bone marrow (BM) MSCs. The clinical condition of the patient was monitored. Immunologic studies before and during MSC treatment were performed. No adverse events related to the MSC infusions were recorded. Throughout the MSC treatment period, the patient showed a growth recovery. Starting the second infusion, the patient experienced an improvement in his respiratory condition, with progressive adaptation to mechanical ventilation. After the third infusion, five hours/die of spontaneous breathing was shown, and after infusion IV, spontaneous ventilation for 24/24 h was recorded. A gradual decrease of lymphocytes and cell subpopulations was observed. No variations in the in vitro T cell response to PHA were determined by MSC treatment as well as for the in vitro B cell response. A decrease in IFN-γ, TNF-α, and IL-10 levels was also detected. Even though we cannot exclude an improvement of pulmonary function due to the physiological maturation, the well-known action of MSCs in the repair of lung tissue, together with the sequence of events observed in our patient, may support the therapeutic role of MSCs in this clinical condition. However, further investigations are necessary to confirm the result and long-term follow-up will be mandatory to confirm the benefits on the pulmonary condition.

Background: In end-stage chronic liver disease, transplantation represents the only curative option. However, the shortage of donors results in the death of many patients. To overcome this gap, it is mandatory to develop new therapeutic options. In the present study, we decellularised pig livers and reseeded them with allogeneic porcine mesenchymal stromal cells (pMSCs) to understand whether extracellular matrix (ECM) can influence and/or promote differentiation into hepatocyte-like cells (HLCs). Methods: After decellularisation with SDS, the integrity of ECM-scaffolds was examined by histological staining, immunofluorescence and scanning electron microscope. DNA quantification was used to assess decellularisation. pMSCs were plated on scaffolds by static seeding and maintained in in vitro culture for 21 days. At 3, 7, 14 and 21 days, seeded ECM scaffolds were evaluated for cellular adhesion and growth. Moreover, the expression of specific hepatic genes was performed by RT-PCR. Results: The applied decellularisation/recellularisation protocol was effective. The number of seeded pMSCs increased over the culture time points. Gene expression analysis of seeded pMSCs displayed a weak induction due to ECM towards HLCs. Conclusions: These results suggest that ECM may address pMSCs to differentiate in hepatocyte-like cells. However, only contact with liver-ECM is not enough to induce complete differentiation.

Background: Chronic low-grade inflammation and activation of the immune system are hallmark pathogenic mechanisms involved in metabolic dysfunction and are related to obesity. In particular, the involvement of regulatory and pro-inflammatory lymphocyte subpopulations has been reported in adults. We evaluated the Th17/Treg lymphocyte balance in obese and normal weight children, in relation with their metabolic status.Methods: We enrolled 50 pediatric patients. According to metabolic status, subjects were classified into: metabolically healthy (MH) and metabolically unhealthy (MU) groups. MU phenotype was defined as the presence of at least one of the following risk factors: blood pressure >90th percentile, glycemia>100 mg/dl, HDL cholesterol 100 mg/dl (130 mg/dl (>10 years), impaired insulin sensitivity with HOMA-IR>97.5th percentile. Patient Treg and Th17 profiles were also evaluated.Results: Based on the presence of metabolic and/or cardiovascular pathological parameters, we classified 15 MU (30%) and 35 MH (70%) children; all MU children were obese. Analyzing the correlations between lymphocyte subpopulations and metabolic data, we noted a correlation between Th17 percentage and systolic hypertension (p = 0.01, r = −0.37); Treg/Th17 ratio and HOMA-IR (p = 0.02, r = 0.32) and systolic hypertension (p = 0.05, r = 0.30).Conclusion: Children with obesity have a high risk of developing metabolic and cardiovascular complications. The Th17/Treg lymphocyte balance appears to be involved in glycemic homeostasis and blood pressure control. Careful and early monitoring of the immune system would facilitate new early preventive strategies in pediatric metabolic diseases.

Abstract Background It has been proposed that mesenchymal stromal cells (MSCs) promote tumor progression by interacting with tumor cells and other stroma cells in the complex network of the tumor microenvironment. We characterized MSCs isolated and expanded from tumor tissues of pediatric patients diagnosed with neuroblastomas (NB-MSCs) to define interactions with the tumor microenvironment. Methods Specimens were obtained from 7 pediatric patients diagnosed with neuroblastoma (NB). Morphology, immunophenotype, differentiation capacity, proliferative growth, expression of stemness and neural differentiation markers were evaluated. Moreover, the ability of cells to modulate the immune response, i.e. inhibition of phytohemagglutinin (PHA) activated peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cytotoxic function, was examined. Gene expression profiles, known to be related to tumor cell stemness, Wnt pathway activation, epithelial-mesenchymal transition (EMT) and tumor metastasis were also evaluated. Healthy donor bone marrow-derived MSCs (BM-MSC) were employed as controls. Results NB-MSCs presented the typical MSC morphology and phenotype. They showed a proliferative capacity superimposable to BM-MSCs. Stemness marker expression (Sox2, Nanog, Oct3/4) was comparable to BM-MSCs. NB-MSC in vitro osteogenic and chondrogenic differentiation was similar to BM-MSCs, but NB-MSCs lacked adipogenic differentiation capacity. NB-MSCs reached senescence phases at a median passage of P7 (range, P5-P13). NB-MSCs exhibited greater immunosuppressive capacity on activated T lymphocytes at a 1:2 (MSC: PBMC) ratio compared with BM-MSCs (p = 0.018). NK cytotoxic activity was not influenced by co-culture, either with BM-MSCs or NB-MSCs. Flow-cytometry cell cycle analysis showed that NB-MSCs had an increased number of cells in the G0-G1 phase compared to BM-MSCs. Transcriptomic profiling results indicated that NB-MSCs were enriched with EMT genes compared to BM-MSCs. Conclusions We characterized the biological features, the immunomodulatory capacity and the gene expression profile of NB-MSCs. The NB-MSC gene expression profile and their functional properties suggest a potential role in promoting tumor escape, invasiveness and metastatic traits of NB cancer cells. A better understanding of the complex mechanisms underlying the interactions between NB cells and NB-derived MSCs should shed new light on potential novel therapeutic approaches.

Acquired congenital esophageal malformations, such as malignant esophageal cancer, require esophagectomy resulting in full thickness resection, which cannot be left untreated. The proposed approach is a polymeric full-thickness scaffold engineered with mesenchymal stem cells (MSCs) to promote and speed up the regeneration process, ensuring adequate support and esophageal tissue reconstruction and avoiding the use of autologous conduits. Copolymers poly-L-lactide-co-poly-ε-caprolactone (PLA-PCL) 70:30 and 85:15 ratio were chosen to prepare electrospun tubular scaffolds. Electrospinning apparatus equipped with two different types of tubular mandrels: cylindrical (∅ 10 mm) and asymmetrical (∅ 10 mm and ∅ 8 mm) were used. Tubular scaffolds underwent morphological, mechanical (uniaxial tensile stress) and biological (MTT and Dapi staining) characterization. Asymmetric tubular geometry resulted in the best properties and was selected for in vivo surgical implantation. Anesthetized pigs underwent full thickness circumferential resection of the mid-lower thoracic esophagus, followed by implantation of the asymmetric scaffold. Preliminary in vivo results demonstrated that detached stitch suture achieved better results in terms of animal welfare and scaffold integration; thus, it is to be preferred to continuous suture.

Mesenchymal stromal cells (MSCs) have been proposed as a potential therapy to treat congenital and acquired lung diseases. Due to their tissue-regenerative, anti-fibrotic, and immunomodulatory properties, MSCs combined with other therapy or alone could be considered as a new approach for repair and regeneration of the lung during disease progression and/or after post- surgical injury. Children interstitial lung disease (chILD) represent highly heterogeneous rare respiratory diseases, with a wild range of age of onset and disease expression. The chILD is characterized by inflammatory and fibrotic changes of the pulmonary parenchyma, leading to gas exchange impairment and chronic respiratory failure associated with high morbidity and mortality. The therapeutic strategy is mainly based on the use of corticosteroids, hydroxychloroquine, azithromycin, and supportive care; however, the efficacy is variable, and their long-term use is associated with severe toxicity. The role of MSCs as treatment has been proposed in clinical and pre-clinical studies. In this narrative review, we report on the currently available on MSCs treatment as therapeutical strategy in chILD. The progress into the therapy of respiratory disease in children is mandatory to ameliorate the prognosis and to prevent the progression in adult age. Cell therapy may be a future therapy from both a pediatric and pediatric surgeon’s point of view.

Immunoglobulin light-chain amyloidosis (AL) is caused by misfolded light chains produced by a small B cell clone. Mesenchymal stromal cells (MSCs) have been reported to affect plasma cell behavior. We aimed to characterize bone marrow (BM)-MSCs from AL patients, considering functional aspects, such as proliferation, differentiation, and immunomodulatory capacities. MSCs were in vitro expanded from the BM of 57 AL patients and 14 healthy donors (HDs). MSC surface markers were analyzed by flow cytometry, osteogenic and adipogenic differentiation capacities were in vitro evaluated, and co-culture experiments were performed in order to investigate MSC immunomodulatory properties towards the ALMC-2 cell line and HD peripheral blood mononuclear cells (PBMCs). AL-MSCs were comparable to HD-MSCs for morphology, immune-phenotype, and differentiation capacities. AL-MSCs showed a reduced proliferation rate, entering senescence at earlier passages than HD-MSCs. The AL-MSC modulatory effect on the plasma-cell line or circulating plasma cells was comparable to that of HD-MSCs. To our knowledge, this is the first study providing a comprehensive characterization of AL-MSCs. It remains to be defined if the observed abnormalities are the consequence of or are involved in the disease pathogenesis. BM microenvironment components in AL may represent the targets for the prevention/treatment of the disease in personalized therapies.

Objective: Chronic renal antibody-mediated rejection (ABMR) is a common cause of allograft failure, but an effective therapy is not available. Extracorporeal photopheresis (ECP) has been proven successful in chronic lung and heart rejection, and graft versus host disease. The aim of this study was to evaluate the effectiveness of ECP in chronic ABMR patients. Patients and Methods: We investigated ECP treatment in 14 patients with biopsy-proven chronic ABMR and stage 2–3 chronic renal failure. The primary aim was to e valuate the eGFR lowering after 1 year of ECP therapy. The ECP responders (R) showed eGFR reduction greater than 20% vs the basal levels. We also evaluated the effectiveness of ECP on proteinuria, anti-HLA antibodies (HLAab), interleukin 6 (IL-6) serum levels, and CD3, CD4, CD8, CD19, NK, Treg and T helper 17 (Th17) circulating cells. Results: Three patients dropped out of the study. The R patients were eight (72.7%) out of the 11 remaining patients. Because ECP was not associated with any adverse reaction, the R patients continued such treatment for up to 3 years, showing a persisting eGFR stabilization. Twenty four hour proteinuria did not increase in the R patients over the follow-up when compared to the non-responder patients (NR). In the R patients, the HLAab levels were reduced and completely cleared in six out of eight patients when compared with the NR patients. The NR HLAab levels also increased after the discontinuation of the ECP. The ECP in the R patients showed a decrease in CD3, CD4, CD8, CD19, and NK circulating cells. The ECP treatment in the R patients also induced Tregs and Th17 cell increases, and a decrease of the IL-6 serum levels. Conclusions: ECP abates the HLAab titer and renal failure progression in patients with chronic renal ABMR, modulating the immune cellular and humoral responses.

In the last few decades, obesity has increased dramatically in pediatric patients. Obesity is a chronic disease correlated with systemic inflammation, characterized by the presence of CD4 and CD8 T cell infiltration and modified immune response, which contributes to the development of obesity related diseases and metabolic disorders, including impaired glucose metabolism. In particular, Treg and Th17 cells are dynamically balanced under healthy conditions, but imbalance occurs in inflammatory and pathological states, such as obesity. Some studies demonstrated that peripheral Treg and Th17 cells exhibit increased imbalance with worsening of glucose metabolic dysfunction, already in children with obesity. In this review, we considered the role of adipose tissue immunomodulation and the potential role played by Treg/T17 imbalance on the impaired glucose metabolism in pediatric obesity. In the patient care, immune monitoring could play an important role to define preventive strategies of pediatric metabolic disease treatments.

In the last decade, the secreting activity of mesenchymal stem/stromal cells (MSCs) has been widely investigated, due to its possible therapeutic role. In fact, MSCs release extracellular vesicles (EVs) containing relevant biomolecules such as mRNAs, microRNAs, bioactive lipids, and signaling receptors, able to restore physiological conditions where regenerative or anti-inflammatory actions are needed. An actual advantage would come from the therapeutic use of EVs with respect to MSCs, avoiding the possible immune rejection, the lung entrapment, improving the safety, and allowing the crossing of biological barriers. A number of concerns still have to be solved regarding the mechanisms determining the beneficial effect of MSC-EVs, the possible alteration of their properties as a consequence of the isolation/purification methods, and/or the best approach for a large-scale production for clinical use. Most of the preclinical studies have been successful, reporting for MSC-EVs a protecting role in acute kidney injury following ischemia reperfusion, a potent anti-inflammatory and anti-fibrotic effects by reducing disease associated inflammation and fibrosis in lung and liver, and the modulation of both innate and adaptive immune responses in graft versus host disease (GVHD) as well as autoimmune diseases. However, the translation of MSC-EVs to the clinical stage is still at the initial phase. Herein, we discuss the therapeutic potential of an acellular product such as MSC derived EVs (MSC-EVs) in acute and chronic pathologies.

We studied Mesenchymal Stromal Cells (MSC) effects in experimental Unilateral Ureteral Obstruction (UUO), a fibrogenic renal disease. Rats were divided in 5 groups: sham, UUO, MSC treated-UUO, ACEi treated-UUO, MSC+ACEi treated- UUO. Data were collected at 1, 7, 21 days. UUO induced monocyte renal infiltration, tubular cell apoptosis, tubular atrophy, interstitial fibrosis and overexpression of TGFβ, Renin mRNA (RENmRNA), increase of Renin, Angiotensin II (AII) and aldosterone serum levels. Both lisinopril (ACEi) and MSC treatment prevented monocyte infiltration, reduced tubular cell apoptosis, renal fibrosis and TGFβ expression. Combined therapy provided a further suppression of monocyte infiltration and tubular injury. Lisinopril alone caused a rebound activation of Renin-Angiotensin System (RAS), while MSC suppressed RENmRNA and Renin synthesis and induced a decrease of AII and aldosterone serum levels. Furthermore, in in-vitro and in-vivo experiments, MSC inhibit Human antigen R (HuR) trascription, an enhancer of RENmRNA stability by IL10 release. In conclusion, we demonstrate that in UUO MSC prevent fibrosis, by decreasing HuR-dependent RENmRNA stability. Our findings give a clue to understand the molecular mechanism through which MSC may prevent fibrosis in a wide and heterogeneous number of diseases that share RAS activation as common upstream pathogenic mechanism.

Alterations in hematopoietic microenvironment of acute lymphoblastic leukemia patients have been claimed to occur, but little is known about the components of marrow stroma in these patients. In this study, we characterized mesenchymal stromal cells (MSCs) isolated from bone marrow (BM) of 45 pediatric patients with acute lymphoblastic leukemia (ALL-MSCs) at diagnosis (day+0) and during chemotherapy treatment (days: +15; +33; +78), the time points being chosen according to the schedule of BM aspirates required by the AIEOP-BFM ALL 2009 treatment protocol. Morphology, proliferative capacity, immunophenotype, differentiation potential, immunomodulatory properties and ability to support long-term hematopoiesis of ALL-MSCs were analysed and compared with those from 41 healthy donors (HD-MSCs). ALL-MSCs were also genetically characterized through array-CGH, conventional karyotyping and FISH analysis. Moreover, we compared ALL-MSCs generated at day+0 with those isolated during chemotherapy. Morphology, immunophenotype, differentiation potential and in vitro life-span did not differ between ALL-MSCs and HD-MSCs. ALL-MSCs showed significantly lower proliferative capacity (p

Background Mesenchymal stromal cells are employed in various different clinical settings in order to modulate immune response. However, relatively little is known about the mechanisms responsible for their immunomodulatory effects, which could be influenced by both the cell source and culture conditions.Design and Methods We tested the ability of a 5% platelet lysate-supplemented medium to support isolation and ex vivo expansion of mesenchymal stromal cells from full-term umbilical-cord blood. We also investigated the biological/functional properties of umbilical cord blood mesenchymal stromal cells, in comparison with platelet lysate-expanded bone marrow mesenchymal stromal cells.Results The success rate of isolation of mesenchymal stromal cells from umbilical cord blood was in the order of 20%. These cells exhibited typical morphology, immunophenotype and differentiation capacity. Although they have a low clonogenic efficiency, umbilical cord blood mesenchymal stromal cells may possess high proliferative potential. The genetic stability of these cells from umbilical cord blood was demonstrated by a normal molecular karyotype; in addition, these cells do not express hTERT and telomerase activity, do express p16ink4a protein and do not show anchorage-independent cell growth. Concerning alloantigen-specific immune responses, umbilical cord blood mesenchymal stromal cells were able to: (i) suppress T- and NK-lymphocyte proliferation, (ii) decrease cytotoxic activity and (iii) only slightly increase interleukin-10, while decreasing interferon-γ secretion, in mixed lymphocyte culture supernatants. While an indoleamine 2,3-dioxygenase-specific inhibitor did not reverse mesenchymal stromal cell-induced suppressive effects, a prostaglandin E2-specific inhibitor hampered the suppressive effect of both umbilical cord blood- and bone marrow-mesenchymal stromal cells on alloantigen-induced cytotoxic activity. Mesenchymal stromal cells from both sources expressed HLA-G.Conclusions Umbilical cord blood- and bone marrow-mesenchymal stromal cells may differ in terms of clonogenic efficiency, proliferative capacity and immunomodulatory properties; these differences may be relevant for clinical applications.

Rituximab 375 mg/m2 weekly for four weeks has significant activity in patients with immune thrombocytopenia. We evaluated the activity of lower dose rituximab (100 mg iv weekly for 4 weeks) in 28 adults with idiopathic thrombocytopenic purpura. Overall (platelet count > 50×109/L) and complete responses (platelet count > 100×109/L) were achieved in 21/28 (75%) and 12/28 (43%) patients respectively. The median time to response and time to complete response were 31 and 44 days respectively. After a median follow-up of 11 months (range 3–18), 7/21 (33%) patients relapsed and 3 needed further treatments. In patients with idiopathic thrombocytopenic purpura, lower dose rituximab seems to show similar activity to standard dose.