The Benefits of the Mediterranean Diet on Inflamm-Aging in Childhood Obesity.

(1) Background: Numerous elements of the Mediterranean diet (MD) have antioxidant and anti-inflammatory qualities. (2) Methods: We present a narrative review of the potential benefits of the Mediterranean dietary pattern (MD) in mitigating aging-related inflammation (inflamm-aging) associated with childhood obesity. The mechanisms underlying chronic inflammation in obesity are also discussed. A total of 130 papers were included after screening abstracts and full texts. (3) Results: A complex interplay between obesity, chronic inflammation, and related comorbidities is documented. The MD emerges as a promising dietary pattern for mitigating inflammation. Studies suggest that the MD may contribute to weight control, improved lipid profiles, insulin sensitivity, and endothelial function, thereby reducing the risk of metabolic syndrome in children and adolescents with obesity. (4) Conclusions: While evidence supporting the anti-inflammatory effects of the MD in pediatric obesity is still evolving, the existing literature underscores its potential as a preventive and therapeutic strategy. However, MD adherence remains low among children and adolescents, necessitating targeted interventions to promote healthier dietary habits. Future high-quality intervention studies are necessary to elucidate the specific impact of the MD on inflammation in diverse pediatric populations with obesity and associated comorbidities.

Potential application of mesenchymal stromal cells as a new therapeutic approach in acute respiratory distress syndrome and pulmonary fibrosis.

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.

Clinical and immunological phenotypes of selective IgM deficiency in children: Results from a multicenter study.

BACKGROUND: A few studies assessed the clinical and immunological features of selective IgM deficiency (SIgMD), especially in the pediatric age. We aimed to characterize the clinical and immunological phenotypes of a cohort of pediatric patients with SIgMD according to the different diagnostic criteria available. METHODS: In this multicenter study, we evaluated pediatric SIgMD patients diagnosed at the Pediatric Clinic in Pavia, Italy, or through the Italian Primary Immunodeficiency NETwork (IPINET) and monitored changes in their diagnosis over a time frame that ranges from several months to several years. RESULTS: Forty-eight patients with SIgMD were included (mean serum IgM: 33 mg/dL). The most common clinical manifestations were recurrent infections (67%) and allergies (48%). Subgroup analysis according to SIgMD definition criteria of the European Society for Immunodeficiencies (ESID) showed no significant difference in clinical manifestations, also considering the group with additional immunological abnormalities. Sixteen patients had long-term follow-up, during which 87% preserved their SIgMD diagnosis, while two patients showed a reduction in IgA in addition to low IgM. CONCLUSIONS: Our data suggest that the identification of a reduction in serum IgM in children should lead to a complete immunological work-up to obtain a comprehensive clinical and immunological characterization of the patient. The follow-up of these patients is fundamental to define the disease evolution and appropriate management.

Bone Marrow Mesenchymal Stem Cells Expanded Inside the Nichoid Micro-Scaffold: a Focus on Anti-Inflammatory Response.

Purpose: Mesenchymal stem cells (MSCs) represent a promising source for stem cell therapies in numerous diseases, including pediatric respiratory system diseases. Characterized by low immunogenicity, high anti-inflammatory, and immunoregulatory features, MSCs demonstrated an excellent therapeutic profile in numerous in vitro and preclinical models. MSCs reside in a specialized physiologic microenvironment, characterized by a unique combination of biophysical, biochemical, and cellular properties. The exploitation of the 3D micro-scaffold Nichoid, which simulates the native niche, enhanced the anti-inflammatory potential of stem cells through mechanical stimulation only, overcoming the limitation of biochemical and xenogenic growth factors application. Materials and Methods: In this work, we expanded pediatric bone marrow MSCs (BM-MSCs) inside the Nichoid and performed a complete cellular characterization with different approaches including viability assays, immunofluorescence analyses, RNA sequencing, and gene expression analysis. Results: We demonstrated that BM-MSCs inside the scaffold remain in a stem cell quiescent state mimicking the condition of the in vivo environment. Moreover, the gene expression profile of these cells shows a significant up-regulation of genes involved in immune response when compared with the flat control. Conclusion: The significant changes in the expression profile of anti-inflammatory genes could potentiate the therapeutic effect of BM-MSCs, encouraging the possible clinical translation for the treatment of pediatric congenital and acquired pulmonary disorders, including post-COVID lung manifestations. Lay Summary: Regenerative medicine is the research field integrating medicine, biology, and biomedical engineering. In this context, stem cells, which are a fundamental cell source able to regenerate tissues and restore damage in the body, are the key component for a regenerative therapeutic approach. When expanded outside the body, stem cells tend to differentiate spontaneously and lose regenerative potential due to external stimuli. For this reason, we exploit the scaffold named Nichoid, which mimics the in vivo cell niche architecture. In this scaffold, mesenchymal stem cells "feel at home" due to the three-dimensional mechanical stimuli, and our findings could be considered as an innovative culture system for the in vitro expansion of stem cells for clinical translation. Future Perspective: The increasing demand of safe and effective cell therapies projects our findings toward the possibility of improving cell therapies based on the use of BM-MSCs, particularly for their clinical translation in lung diseases.

Autoantibodies neutralizing type I IFNs underlie West Nile virus encephalitis in ∼40% of patients.

Mosquito-borne West Nile virus (WNV) infection is benign in most individuals but can cause encephalitis in <1% of infected individuals. We show that ∼35% of patients hospitalized for WNV disease (WNVD) in six independent cohorts from the EU and USA carry auto-Abs neutralizing IFN-α and/or -ω. The prevalence of these antibodies is highest in patients with encephalitis (∼40%), and that in individuals with silent WNV infection is as low as that in the general population. The odds ratios for WNVD in individuals with these auto-Abs relative to those without them in the general population range from 19.0 (95% CI 15.0-24.0, P value <10-15) for auto-Abs neutralizing only 100 pg/ml IFN-α and/or IFN-ω to 127.4 (CI 87.1-186.4, P value <10-15) for auto-Abs neutralizing both IFN-α and IFN-ω at a concentration of 10 ng/ml. These antibodies block the protective effect of IFN-α in Vero cells infected with WNV in vitro. Auto-Abs neutralizing IFN-α and/or IFN-ω underlie ∼40% of cases of WNV encephalitis.

A Strategy for the Selection of RT-qPCR Reference Genes Based on Publicly Available Transcriptomic Datasets.

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.

New therapeutic approaches in pediatric diseases: Mesenchymal stromal cell and mesenchymal stromal cell-derived extracellular vesicles as new drugs.

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.

Lung mesenchymal cells from patients with COVID-19 driven lung fibrosis: Several features with CTD-ILD derived cells but with higher response to fibrogenic signals and might be more pro-inflammatory.

A subset of severe COVID19 patients develop pulmonary fibrosis, but the pathophysiology of this complication is still unclear. We previously described the possibility to isolate lung mesenchymal cells (LMC) by culturing broncho-alveolar lavage (BAL) cells from patients with pulmonary fibrosis or chronic lung allograft dysfunction. Aim of this study was to investigate the possibility to isolate and characterize LMC from BAL of patients that, two months after discharge for severe COVID19, show CT signs of post-COVID19 fibrosis (Post-COVID) and in some cases has been considered transplant indication. Results were compared with those from BAL of patients with collagen tissue disease-associated interstitial fibrosis (CTD-ILD). BAL fluid levels of TGFß, VEGF, TIMP2, RANTES, IL6, IL8, and PAI1 were assessed. LMC were cultured and expanded, phenotyped by flow cytometry, and tested for osteogenic and adipogenic differentiation. Finally, we tested immunomodulatory and proliferative capabilities, collagen I production + /- TGF-beta stimulation. BAL cytokine and growth factor levels were comparable in the two groups. Efficiency of isolation from BAL was 100% in post-COVID compared to 63% in CTD-ILD. LMC from post-COVID were positive for CD105, CD73, CD90, and negative for CD45, CD34, CD19 and HLA-DR as in CTD-ILD samples. Post-COVID LMC displayed higher collagen production with respect to CTD-ILD LMC. Immunomodulatory capacity towards lymphocytes was very low, while Post-COVID LMC significantly upregulated pro-inflammatory cytokine production by healthy PBMCs. Our preliminary data suggest that LMC from post-COVID19 fibrosis patients share several features with CTD-ILD ones but might have a higher response to fibrogenic signals and pro-inflammatory profile.

Allogeneic Mesenchymal Stromal Cells as a Global Pediatric Prospective Approach in the Treatment of Respiratory Failure Associated with Surfactant Protein C Dysfunction.

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.

Mesenchymal Stromal Cell on Liver Decellularised Extracellular Matrix for Tissue Engineering.

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.

Type D lymphomatoid papulosis with pityriasis lichenoides et varioliformis acuta-like features in a child with parvovirus infection: a controversial diagnosis in the spectrum of lymphoid proliferations: case report and literature review.

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.

CD73-Adenosinergic Axis Mediates the Protective Effect of Extracellular Vesicles Derived from Mesenchymal Stromal Cells on Ischemic Renal Damage in a Rat Model of Donation after Circulatory Death.

We propose a new organ-conditioning strategy based on mesenchymal stromal cell (MSCs)/extracellular vesicle (EVs) delivery during hypothermic perfusion. MSCs/EVs marker CD73 is present on renal proximal tubular cells, and it protects against renal ischemia-reperfusion injury by converting adenosine monophosphate into adenosine (ADO). In this study, after checking if CD73-silenced EVs (EVsi) would impact in vitro tubular-cell proliferation, we perfused kidneys of a rat model of donation after circulatory death, with Belzer solution (BS) alone, BS supplemented with MSCs, EVs, or EVsi. The ADO and ATP levels were measured in the effluents and tissues. Global renal ischemic damage score (GRS), and tubular cell proliferation index (IPT) were evaluated in the tissue. EVsi did not induce cell proliferation in vitro. Ex vivo kidneys perfused with BS or BS + EVsi showed the worst GRS and higher effluent ADO levels than the MSC- and EV-perfused kidneys. In the EV-perfused kidneys, the tissue and effluent ATP levels and IPT were the highest, but not if CD73 was silenced. Tissue ATP content was positively correlated with tissue ADO content and negatively correlated with effluent ADO level in all groups. In conclusion, kidney conditioning with EVs protects against ischemic damage by activating the CD73/ADO system.

The Role of Hypoxia in Improving the Therapeutic Potential of Mesenchymal Stromal Cells. A Comparative Study From Healthy Lung and Congenital Pulmonary Airway Malformations in Infants.

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.

Serum and breastmilk SARS-CoV-2 specific antibodies following BNT162b2 vaccine: prolonged protection from SARS-CoV-2 in newborns and older children.

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 <0.0001). Higher antibody levels were observed at T2 and lower values at T3 versus T2 (P = 0.007). After 6 months, all patients had serum IgG, but three of 18 (16%) had serum IgA. In breastmilk, sIgA was present at T1 and T2 and decreased after 6 months at T3 (P = 0.002). Breastmilk sIgG levels increased at T1 and T2 and peaked at T3 (P = 0.008). CONCLUSION: Secretory antibodies were transmitted through breastmilk until 6 months after anti-COVID-19 mRNA vaccination. Protection of the newborn through breastfeeding needs to be addressed.

Engineered Full Thickness Electrospun Scaffold for Esophageal Tissue Regeneration: From In Vitro to In Vivo Approach.

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.

Neuroblastoma Tumor-Associated Mesenchymal Stromal Cells Regulate the Cytolytic Functions of NK Cells.

Neuroblastoma tumor-associated mesenchymal stromal cells (NB-TA-MSC) have been extensively characterized for their pro-tumorigenic properties, while their immunosuppressive potential, especially against NK cells, has not been thoroughly investigated. Herein, we study the immune-regulatory potential of six primary young and senescent NB-TA-MSC on NK cell function. Young cells display a phenotype (CD105+/CD90+/CD73+/CD29+/CD146+) typical of MSC cells and, in addition, express high levels of immunomodulatory molecules (MHC-I, PDL-1 and PDL-2 and transcriptional-co-activator WWTR1), able to hinder NK cell activity. Notably, four of them express the neuroblastoma marker GD2, the most common target for NB immunotherapy. From a functional point of view, young NB-TA-MSC, contrary to the senescent ones, are resistant to activated NK cell-mediated lysis, but this behavior is overcome using anti-CD105 antibody TRC105 that activates antibody-dependent cell-mediated cytotoxicity. In addition, proliferating NB-TA-MSC, but not the senescent ones, after six days of co-culture, inhibit proliferation, expression of activating receptors and cytolytic activity of freshly isolated NK. Inhibitors of the soluble immunosuppressive factors L-kynurenine and prostaglandin E2 efficiently counteract this latter effect. Our data highlight the presence of phenotypically heterogeneous NB-TA-MSC displaying potent immunoregulatory properties towards NK cells, whose inhibition could be mandatory to improve the antitumor efficacy of targeted immunotherapy.

Mesenchymal Stromal Cells for the Treatment of Interstitial Lung Disease in Children: A Look from Pediatric and Pediatric Surgeon Viewpoints.

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.

Bone Marrow Microenvironment in Light-Chain Amyloidosis: In Vitro Expansion and Characterization of Mesenchymal Stromal Cells.

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.

Proliferation Pattern of Pediatric Tumor-Derived Mesenchymal Stromal Cells and Role in Cancer Dormancy: A Perspective of Study for Surgical Strategy.

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.

SARS-CoV-2 Exposed Mesenchymal Stromal Cell from Congenital Pulmonary Airway Malformations: Transcriptomic Analysis and the Expression of Immunomodulatory Genes.

The inflammatory response plays a central role in the complications of congenital pulmonary airway malformations (CPAM) and severe coronavirus disease 2019 (COVID-19). The aim of this study was to evaluate the transcriptional changes induced by SARS-CoV-2 exposure in pediatric MSCs derived from pediatric lung (MSCs-lung) and CPAM tissues (MSCs-CPAM) in order to elucidate potential pathways involved in SARS-CoV-2 infection in a condition of exacerbated inflammatory response. MSCs-lung and MSCs-CPAM do not express angiotensin-converting enzyme 2 (ACE2) and transmembrane serine protease 2 (TRMPSS2). SARS-CoV-2 appears to be unable to replicate in MSCs-CPAM and MSCs-lung. MSCs-lung and MSCs-CPAM maintained the expression of stemness markers MSCs-lung show an inflammatory response (IL6, IL1B, CXCL8, and CXCL10), and the activation of Notch3 non-canonical pathway; this route appears silent in MSCs-CPAM, and cytokine genes expression is reduced. Decreased value of p21 in MSCs-lung suggested no cell cycle block, and cells did not undergo apoptosis. MSCs-lung appears to increase genes associated with immunomodulatory function but could contribute to inflammation, while MSCs-CPAM keeps stable or reduce the immunomodulatory receptors expression, but they also reduce their cytokines expression. These data indicated that, independently from their perilesional or cystic origin, the MSCs populations already present in a patient affected with CPAM are not permissive for SARS-CoV-2 entry, and they will not spread the disease in case of infection. Moreover, these MSCs will not undergo apoptosis when they come in contact with SARS-CoV-2; on the contrary, they maintain their staminality profile.