A comprehensive review on the role of mesenchymal stromal/stem cells in the management of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease with systemic manifestations. Although the success of immune modulatory drug therapy is considerable, about 40% of patients do not respond to treatment. Mesenchymal stromal/stem cells (MSCs) have been demonstrated to have therapeutic potential for inflammatory diseases.

AREAS COVERED

This review provides an update on RA disease and on pre-clinical and clinical studies using MSCs from bone marrow, umbilical cord, adipose tissue, and dental pulp, to regulate the immune response. Moreover, the clinical use, safety, limitations, and future perspective of MSCs in RA are discussed. Using the PubMed database and ClincalTrials.gov, peer-reviewed full-text papers, abstracts and clinical trials were identified from 1985 through to April 2023.

EXPERT OPINION

MSCs demonstrated a satisfactory safety profile and potential for clinical efficacy. However, it is mandatory to deepen the investigations on how MSCs affect the proinflammatory deregulated RA patients' cells. MSCs are potentially good candidates for severe RA patients not responding to conventional therapies but a long-term follow-up after stem cells treatment and standardized protocols are needed. Future research should focus on well-designed multicenter randomized clinical trials with adequate sample sizes and properly selected patients satisfying RA criteria for a valid efficacy evaluation.

Zirconia Hybrid Dental Implants Influence the Biological Properties of Neural Crest-Derived Mesenchymal Stromal Cells

Dental implants are regularly employed in tooth replacement, the good clinical outcome of which is strictly correlated to the choice of an appropriate implant biomaterial. Titanium-based implants are considered the gold standard for rehabilitation of edentulous spaces. However, the insurgence of allergic reactions, cellular sensitization and low integration with dental and gingival tissues lead to poor osseointegration, affecting the implant stability in the bone and favoring infections and inflammatory processes in the peri-implant space. These failures pave the way to develop and improve new biocompatible implant materials. CERID dental implants are made of a titanium core embedded in a zirconium dioxide ceramic layer, ensuring absence of corrosion, a higher biological compatibility and a better bone deposition compared to titanium ones. We investigated hDPSCs' biological behavior, i.e., cell adhesion, proliferation, morphology and osteogenic potential, when seeded on both CERID and titanium implants, before and after cleansing with two different procedures. SEM and AFM analysis of the surfaces showed that while CERID disks were not significantly affected by the cleansing system, titanium ones exhibited well-visible modifications after brush treatment, altering cell morphology. The proliferation rate of DPSCs was increased for titanium, while it remained unaltered for CERID. Both materials hold an intrinsic potential to promote osteogenic commitment of neuro-ectomesenchymal stromal cells. Interestingly, the CERID surface mitigated the immune response by inducing an upregulation of anti-inflammatory cytokine IL-10 on activated PBMCs when a pro-inflammatory microenvironment was established. Our in vitro results pave the way to further investigations aiming to corroborate the potential of CERID implants as suitable biomaterials for dental implant applications.

Synergy of Nanotopography and Electrical Conductivity of PEDOT/PSS for Enhanced Neuronal Development

Biomaterials able to promote neuronal development and neurite outgrowth are highly desired in neural tissue engineering for the repair of damaged or disrupted neural tissue and restoring the axonal connection. For this purpose, the use of either electroactive or micro- and nanostructured materials has been separately investigated. Here, the use of a nanomodulated conductive poly(3,4-ethylendioxithiophene) poly(styrenesulfonate) (PEDOT/PSS) substrate that exhibits instructive topographical and electrical cues at the same time was investigated for the first time. In particular, thin films featuring grooves with sizes comparable with those of neuronal neurites (NanoPEDOT) were fabricated by electrochemical polymerization of PEDOT/PSS on a nanomodulated polycarbonate template. The ability of NanoPEDOT to support neuronal development and direct neurite outgrowth was demonstrated by assessing cell viability and proliferation, expression of neuronal markers, average neurite length, and direction of neuroblastoma N2A cells induced to differentiate on this novel support. In addition to the beneficial effect of the nanogrooved topography, a 30% increase was shown in the average length of neurites when differentiating cells were subjected to an electrical stimulation of a few microamperes for 6 h. The results reported here suggest a favorable effect on the neuronal development of the synergistic combination of nanotopography and electrical stimulation, supporting the use of NanoPEDOT in neural tissue engineering to promote physical and functional reconnection of impaired neural networks.

Cell transplantation-based regenerative medicine in liver diseases

This review aims to evaluate the current preclinical state of liver bioengineering, the clinical context for liver cell therapies, the cell sources, the delivery routes, and the results of clinical trials for end-stage liver disease. Different clinical settings, such as inborn errors of metabolism, acute liver failure, chronic liver disease, liver cirrhosis, and acute-on-chronic liver failure, as well as multiple cellular sources were analyzed; namely, hepatocytes, hepatic progenitor cells, biliary tree stem/progenitor cells, mesenchymal stromal cells, and macrophages. The highly heterogeneous clinical scenario of liver disease and the availability of multiple cellular sources endowed with different biological properties make this a multidisciplinary translational research challenge. Data on each individual liver disease and more accurate endpoints are urgently needed, together with a characterization of the regenerative pathways leading to potential therapeutic benefit. Here, we critically review these topics and identify related research needs and perspectives in preclinical and clinical settings.

Different Roles of Apoptosis and Autophagy in the Development of Human Colorectal Cancer

Colorectal cancer (CRC) remains a major life-threatening malignancy, despite numerous therapeutic and screening attempts. Apoptosis and autophagy are two processes that share common signaling pathways, are linked by functional relationships and have similar protein components. During the development of cancer, the two processes can trigger simultaneously in the same cell, causing, in some cases, an inhibition of autophagy by apoptosis or apoptosis by autophagy. Malignant cells that have accumulated genetic alterations can take advantage of any alterations in the apoptotic process and as a result, progress easily in the cancerous transformation. Autophagy often plays a suppressive role during the initial stages of carcinogenicity, while in the later stages of cancer development it can play a promoting role. It is extremely important to determine the regulation of this duality of autophagy in the development of CRC and to identify the molecules involved, as well as the signals and the mechanisms behind it. All the reported experimental results indicate that, while the antagonistic effects of autophagy and apoptosis occur in an adverse environment characterized by deprivation of oxygen and nutrients, leading to the formation and development of CRC, the effects of promotion and collaboration usually involve an auxiliary role of autophagy compared to apoptosis. In this review, we elucidate the different roles of autophagy and apoptosis in human CRC development.

miRNAs, Mesenchymal Stromal Cells and Major Neoplastic and Inflammatory Skin Diseases: A Page Being Written: A Systematic Review

Micro RNAs (miRNAs) are a type of non-coding RNA (ncRNA) and typically interact with specific target mRNAs through complementary base pairing, affecting their translation and/or stability. MiRNAs regulate nearly all cellular functions, including the cell fate of mesenchymal stromal cells (MSCs). It is now accepted that various pathologies arise at the stem level, and, in this scenario, the role played by miRNAs in the fate of MSCs becomes of primary concern. Here we have considered the existing literature in the field of miRNAs, MSCs and skin diseases, classified as inflammatory (such as psoriasis and atopic dermatitis-AD) and neoplastic (melanoma and non-melanoma-skin-cancer including squamous cell and basal cell carcinoma) diseases. In this scoping review article, the evidence recovered indicates that this topic has attracted attention, but it is still a matter of opinion. A protocol for this review was registered in PROSPERO with the registration number "CRD42023420245". According to the different skin disorders and to the specific cellular mechanisms considered (cancer stem cells, extracellular vesicles, inflammation), miRNAs may play a pro- or anti-inflammatory, as well as a tumor suppressive, or supporting, role, indicating a complex regulation of their function. It is evident that the mode of action of miRNAs is more than a switch on-off, and all the observed effects of their dysregulated expression must be checked in a detailed analysis of the targeted proteins. The involvement of miRNAs has been studied mainly for squamous cell carcinoma and melanoma, and much less in psoriasis and AD; different mechanisms have been considered, such as miRNAs included in extracellular vesicles derived both from MSCs or tumor cells, miRNAs involved in cancer stem cells formation, up to miRNAs as candidates to be new therapeutic tools.

Flow-dependent shear stress affects the biological properties of pericyte-like cells isolated from human dental pulp

BACKGROUND

Human dental pulp stem cells represent a mesenchymal stem cell niche localized in the perivascular area of dental pulp and are characterized by low immunogenicity and immunomodulatory/anti-inflammatory properties. Pericytes, mural cells surrounding the endothelium of small vessels, regulate numerous functions including vessel growth, stabilization and permeability. It is well established that pericytes have a tight cross talk with endothelial cells in neoangiogenesis and vessel stabilization, which are regulated by different factors, i.e., microenvironment and flow-dependent shear stress. The aim of this study was to evaluate the effects of a pulsatile unidirectional flow in the presence or not of an inflammatory microenvironment on the biological properties of pericyte-like cells isolated from human dental pulp (hDPSCs).

METHODS

Human DPSCs were cultured under both static and dynamic conditions with or without pre-activated peripheral blood mononuclear cells (PBMCs). Pulsatile unidirectional flow shear stress was generated by using a specific peristaltic pump. The angiogenic potential and inflammatory properties of hDPSCs were evaluated through reverse phase protein microarrays (RPPA), confocal immunofluorescence and western blot analyses.

RESULTS

Our data showed that hDPSCs expressed the typical endothelial markers, which were up-regulated after endothelial induction, and were able to form tube-like structures. RPPA analyses revealed that these properties were modulated when a pulsatile unidirectional flow shear stress was applied to hDPSCs. Stem cells also revealed a downregulation of the immune-modulatory molecule PD-L1, in parallel with an up-regulation of the pro-inflammatory molecule NF-kB. Immune-modulatory properties of hDPSCs were also reduced after culture under flow-dependent shear stress and exposure to an inflammatory microenvironment. This evidence was strengthened by the detection of up-regulated levels of expression of pro-inflammatory cytokines in PBMCs.

CONCLUSIONS

In conclusion, the application of a pulsatile unidirectional flow shear stress induced a modulation of immunomodulatory/inflammatory properties of dental pulp pericyte-like cells.

Human dental pulp stem cells (hDPSCs) promote the lipofibroblast transition in the early stage of a fibro-inflammatory process

Introduction: In autoimmune diseases, particularly in systemic sclerosis and chronic periaortitis, a strict correlation between chronic inflammation and fibrosis exists. Since the currently used drugs prove mostly effective in suppressing inflammation, a better comprehension of the molecular mechanisms exerted by cell types implicated in fibro-inflammation is needed to develop novel therapeutic strategies. Mesenchymal stromal/stem cells (MSCs) are being matter of deep investigation to unveil their role in the evolution of fibrogenetic process. Several findings pointed out the controversial implication of MSCs in these events, with reports lining at a beneficial effect exerted by external MSCs and others highlighting a direct contribution of resident MSCs in fibrosis progression. Human dental pulp stem cells (hDPSCs) have demonstrated to hold promise as potential therapeutic tools due to their immunomodulatory properties, which strongly support their contribution to tissue regeneration. Methods: Our present study evaluated hDPSCs response to a fibro-inflammatory microenvironment, mimicked in vitro by a transwell co-culture system with human dermal fibroblasts, at early and late culture passages, in presence of TGF-β1, a master promoter of fibrogenesis. Results and Discussion: We observed that hDPSCs, exposed to acute fibro-inflammatory stimuli, promote a myofibroblast-to-lipofibroblast transition, likely based on BMP2 dependent pathways. Conversely, when a chronic fibro-inflammatory microenvironment is generated, hDPSCs reduce their anti-fibrotic effect and acquire a pro-fibrotic phenotype. These data provide the basis for further investigations on the response of hDPSCs to varying fibro-inflammatory conditions.

PEDOT: PSS promotes neurogenic commitment of neural crest-derived stem cells

Poly (3,4-ethylendioxythiophene) polystyrene sulphonate (PEDOT:PSS) is the workhorse of organic bioelectronics and is steadily gaining interest also in tissue engineering due to the opportunity to endow traditional biomaterials for scaffolds with conductive properties. Biomaterials capable of promoting neural stem cell differentiation by application of suitable electrical stimulation protocols are highly desirable in neural tissue engineering. In this study, we evaluated the adhesion, proliferation, maintenance of neural crest stemness markers and neurogenic commitment of neural crest-derived human dental pulp stem cells (hDPSCs) cultured on PEDOT:PSS nanostructured thin films deposited either by spin coating (SC-PEDOT) or by electropolymerization (ED-PEDOT). In addition, we evaluated the immunomodulatory properties of hDPSCs on PEDOT:PSS by investigating the expression and maintenance of the Fas ligand (FasL). We found that both SC-PEDOT and ED-PEDOT thin films supported hDPSCs adhesion and proliferation; however, the number of cells on the ED-PEDOT after 1 week of culture was significantly higher than that on SC-PEDOT. To be noted, both PEDOT:PSS films did not affect the stemness phenotype of hDPSCs, as indicated by the maintenance of the neural crest markers Nestin and SOX10. Interestingly, neurogenic induction was clearly promoted on ED-PEDOT, as indicated by the strong expression of MAP-2 and β—Tubulin-III as well as evident cytoskeletal reorganisation and appreciable morphology shift towards a neuronal-like shape. In addition, strong FasL expression was detected on both undifferentiated or undergoing neurogenic commitment hDPSCs, suggesting that ED-PEDOT supports the expression and maintenance of FasL under both expansion and differentiation conditions.

Characterization of Dental Pulp Stem Cells Response to Bone Substitutes Biomaterials in Dentistry

Bone substitute biomaterials (BSBs) represent a promising alternative to bone autografts, due to their biocompatibility, osteoconduction, slow resorption rates, and the ability to define and maintain volume for bone gain in dentistry. Many biomaterials are tailored to provide structural and biological support for bone regeneration, and allow the migration of bone-forming cells into the bone defect. Neural crest-derived stem cells isolated from human dental pulp (hDPSCs) represent a suitable stem cell source to study the biological effects of BSBs on osteoprogenitor cells involved in the physiological bone regenerative processes. This study aimed to evaluate how three different BSBs affect the stem cell properties, osteogenic differentiation, and inflammatory properties of hDPSCs. Our data highlight that BSBs do not alter cell proliferation and stemness markers expression, nor induce any inflammatory responses. Bone metabolism data show that hDPSCs exposed to the three BSBs distinctively secrete the factors supporting osteoblast activity and osteoclast activity. Our data indicate that (i) hDPSCs are a suitable stem cell source to study the effects of BSBs, and that (ii) the formulation of BSBs may condition the biological properties of stem cells, suggesting their versatile suitability to different dentistry applications.

Liquid flow in scaffold derived from natural source: experimental observations and biological outcome

This study investigates the biological effects on a 3D scaffold based on hydroxyapatite cultured with MC3T3 osteoblasts in response to flow-induced shear stress (FSS). The scaffold adopted here (B-HA) derives from the biomorphic transformation of natural wood and its peculiar channel geometry mimics the porous structure of the bone. From the point of view of fluid dynamics, B-HA can be considered a network of micro-channels, intrinsically offering the advantages of a microfluidic system. This work, for the first time, offers a description of the fluid dynamic properties of the B-HA scaffold, which are strongly connected to its morphology. These features are necessary to determine the FSS ranges to be applied during in vitro studies to get physiologically relevant conditions. The selected ranges of FSS promoted the elongation of the attached cells along the flow direction and early osteogenic cell differentiation. These data confirmed the ability of B-HA to promote the differentiation process along osteogenic lineage. Hence, such a bioactive and naturally derived scaffold can be considered as a promising tool for bone regeneration applications.

Expression of Autophagic and Inflammatory Markers in Normal Mucosa of Individuals with Colorectal Adenomas: A Cross Sectional Study among Italian Outpatients Undergoing Colonoscopy

Colorectal cancer (CRC) ranks among the three most common cancers in terms of both cancer incidence and cancer-related deaths in Western industrialized countries. Lifetime risk of colorectal cancer may reach 6% of the population living in developed countries. In the current era of personalized medicine, CRC is no longer considered as a single entity. In more recent years many studies have described the distinct differences in epidemiology, pathogenesis, genetic and epigenetic alterations, molecular pathways and outcome depending on the anatomical site. The aim of our study is to assess in a multidimensional model the association between metabolic status and inflammatory and autophagic changes in the normal colorectal mucosa classified as right-sided, left-sided and rectum, and the presence of adenomas. One hundred and sixteen patients undergoing colonoscopy were recruited and underwent a complete serum lipid profile, immunofluorescence analysis of colonic biopsies for MAPLC3 and myeloperoxidase expression, matched with clinical and anthropometric characteristics. Presence of adenomas correlated with cholesterol (total and LDL) levels, IL-6 levels, and MAPLC3 tissue expression, especially in the right colon. In conclusion, serum IL-6 amount and autophagic markers could be good predictors of the presence of colorectal adenomas.

Effects of Energy Drink Acute Assumption in Gastrointestinal Tract of Rats

Energy drinks (EDs) are non-alcoholic beverages containing high amounts of caffeine and other psychoactive substances. EDs also contain herbal extract whose concentration is usually unknown. EDs can have several adverse effects on different organs and systems, but their effects on the gastrointestinal (GI) tract have been poorly investigated. To determine the acute effects of EDs on the GI tract, we administered EDs, coffee, soda cola, or water to Sprague–Dawley rats (n = 7 per group, randomly assigned) for up to five days, and analyzed the histopathological changes in the GI tract. Data were compared among groups by Kruskal–Wallis or Mann–Whitney tests. We found that, while EDs did not cause any evident acute lesion to the GI tract, they triggered eosinophilic infiltration in the intestinal mucosa; treatment with caffeine alone at the same doses found in EDs leads to the same effects, suggesting that it is caffeine and not other substances present in the EDs that causes this infiltration. The interruption of caffeine administration leads to the complete resolution of eosinophilic infiltration. As no systemic changes in pro-inflammatory or immunomodulating molecules were observed, our data suggest that caffeine present in ED can cause a local, transient inflammatory status that recruits eosinophils.

Role of PD-L1 in licensing immunoregulatory function of dental pulp mesenchymal stem cells

Background

Dental pulp stem cells (DPSCs) are low immunogenic and hold immunomodulatory properties that, along with their well-established multi-potency, might enhance their potential application in autoimmune and inflammatory diseases. The present study focused on the ability of DPSCs to modulate the inflammatory microenvironment through PD1/PD-L1 pathway.

Methods

Inflammatory microenvironment was created in vitro by the activation of T cells isolated from healthy donors and rheumatoid arthritis (RA) patients with anti-CD3 and anti-CD28 antibodies. Direct and indirect co-cultures between DPSCs and PBMCs were carried out to evaluate the activation of immunomodulatory checkpoints in DPSCs and the inflammatory pattern in PBMCs.

Results

Our data suggest that the inflammatory stimuli trigger DPSCs immunoregulatory functions that can be exerted by both direct and indirect contact. As demonstrated by using a selective PD-L1 inhibitor, DPSCs were able to activate compensatory pathways targeting to orchestrate the inflammatory process by modulating pro-inflammatory cytokines in pre-activated T lymphocytes. The involvement of PD-L1 mechanism was also observed in autologous inflammatory status (pulpitis) and after direct exposure to pre-activated T cells from RA patients suggesting that immunomodulatory/anti-inflammatory properties are strictly related to their stemness status.

Conclusions

Our findings point out that the communication with the inflammatory microenvironment is essential in licensing their immunomodulatory properties.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02664-4.

Alternative splicing of NF-YA promotes prostate cancer aggressiveness and represents a new molecular marker for clinical stratification of patients

BACKGROUND

Approaches based on expression signatures of prostate cancer (PCa) have been proposed to predict patient outcomes and response to treatments. The transcription factor NF-Y participates to the progression from benign epithelium to both localized and metastatic PCa and is associated with aggressive transcriptional profile. The gene encoding for NF-YA, the DNA-binding subunit of NF-Y, produces two alternatively spliced transcripts, NF-YAs and NF-YAl. Bioinformatic analyses pointed at NF-YA splicing as a key transcriptional signature to discriminate between different tumor molecular subtypes. In this study, we aimed to determine the pathophysiological role of NF-YA splice variants in PCa and their association with aggressive subtypes.

METHODS

Data on the expression of NF-YA isoforms were extracted from the TCGA (The Cancer Genome Atlas) database of tumor prostate tissues and validated in prostate cell lines. Lentiviral transduction and CRISPR-Cas9 technology allowed the modulation of the expression of NF-YA splice variants in PCa cells. We characterized 3D cell cultures through in vitro assays and RNA-seq profilings. We used the rank-rank hypergeometric overlap approach to identify concordant/discordant gene expression signatures of NF-YAs/NF-YAl-overexpressing cells and human PCa patients. We performed in vivo studies in SHO-SCID mice to determine pathological and molecular phenotypes of NF-YAs/NF-YAl xenograft tumors.

RESULTS

NF-YA depletion affects the tumorigenic potential of PCa cells in vitro and in vivo. Elevated NF-YAs levels are associated to aggressive PCa specimens, defined by Gleason Score and TNM classification. NF-YAl overexpression increases cell motility, while NF-YAs enhances cell proliferation in PCa 3D spheroids and xenograft tumors. The transcriptome of NF-YAs-spheroids has an extensive overlap with localized and metastatic human PCa signatures. According to PCa PAM50 classification, NF-YAs transcript levels are higher in LumB, characterized by poor prognosis compared to LumA and basal subtypes. A significant decrease in NF-YAs/NF-YAl ratio distinguishes PCa circulating tumor cells from cancer cells in metastatic sites, consistently with pro-migratory function of NF-YAl. Stratification of patients based on NF-YAs expression is predictive of clinical outcome.

CONCLUSIONS

Altogether, our results indicate that the modulation of NF-YA isoforms affects prostate pathophysiological processes and contributes to cancer-relevant phenotype, in vitro and in vivo. Evaluation of NF-YA splicing may represent a new molecular strategy for risk assessment of PCa patients.

GD2 CAR T cells against human glioblastoma

Glioblastoma is the most malignant primary brain tumor and is still in need of effective medical treatment. We isolated patient-derived glioblastoma cells showing high GD2 antigen expression representing a potential target for CAR T strategy. Data highlighted a robust GD2 CAR antitumor potential in 2D and 3D glioblastoma models associated with a significant and CAR T-restricted increase of selected cytokines. Interestingly, immunosuppressant TGF β1, expressed in all co-cultures, did not influence antitumor activity. The orthotopic NOD/SCID models using primary glioblastoma cells reproduced human histopathological features. Considering still-conflicting data on the delivery route for targeting brain tumors, we compared intracerebral versus intravenous CAR T injections. We report that the intracerebral route significantly increased the length of survival time in a dose-dependent manner, without any side effects. Collectively, the proposed anti-GD2 CAR can counteract human glioblastoma potentially opening a new therapeutic option for a still incurable cancer.

Possible Association Between DHEA and PKCε in Hepatic Encephalopathy Amelioration: A Pilot Study

Objective: Hepatic encephalopathy (HE) is a neuropsychiatric syndrome caused by liver failure and by an impaired neurotransmission and neurological function caused by hyperammonemia (HA). HE, in turn, decreases the phosphorylation of protein kinase C epsilon (PKCε), contributing to the impairment of neuronal functions. Dehydroepiandrosterone (DHEA) exerts a neuroprotective effect by increasing the GABAergic tone through GABA_A receptor stimulation. Therefore, we investigated the protective effect of DHEA in an animal model of HE, and the possible modulation of PKCε expression in different brain area.

Methods: Fulminant hepatic failure was induced in 18 male, Sprague–Dawley rats by i.p. administration of 3 g/kg D-galactosamine, and after 30 min, a group of animals received a subcutaneous injection of 25 mg/kg (DHEA) repeated twice a day (3 days). Exploratory behavior and general activity were evaluated 24 h and 48 h after the treatments by the open field test. Then, brain cortex and cerebellum were used for immunoblotting analysis of PKCε level.

Results: DHEA administration showed a significant improvement of locomotor activity both 24 and 48 h after D-galactosamine treatment (^****p < 0.0001) but did not ameliorate liver parenchymal degeneration. Western blot analysis revealed a reduced immunoreactivity of PKCε (^*p < 0.05) following D-galactosamine treatment in rat cortex and cerebellum. After the addition of DHEA, PKCε increased in the cortex in comparison with the D-galactosamine-treated (^***p < 0.001) and control group (^*p < 0.05), but decreased in the cerebellum (^*p < 0.05) with respect to the control group. PKCε decreased after treatment with NH₄Cl alone and in combination with DHEA in both cerebellum and cortex (^****p < 0.0001). MTS assay demonstrated the synergistic neurotoxic action of NH₄Cl and glutamate pretreatment in cerebellum and cortex along with an increased cell survival after DHEA pretreatment, which was significant only in the cerebellum (^*p < 0.05).

Conclusion: An association between the DHEA-mediated increase of PKCε expression and the improvement of comatose symptoms was observed. PKCε activation and expression in the brain could inhibit GABA-ergic tone counteracting HE symptoms. In addition, DHEA seemed to ameliorate the symptoms of HE and to increase the expression of PKCε in cortex and cerebellum.

Autoimmunity Profiles as Prognostic Indicators in Patients with Colorectal Cancer versus Those with Cancer at Other Sites: A Prospective Study

Simple Summary

The clinical utility of tumor-associated autoantibodies (TAABs) detected in patient sera with different types of cancer has not yet been established. Their possible use in early cancer detection, oncological follow-up, and patient prognosis is highly desirable. We developed a prospective study to investigate the role of TAABs in a five-year survival analysis in different types of cancer patients. Overall, overproduction of TAABs is associated with advanced oncological disease, the presence of metastasis, and poorer prognosis of cancer patients. There is evidence that more intensive follow-up programs provide different results for colorectal cancer than other cancers, because more intensive follow-up improves survival and is cost-effective in colorectal cancer. It is necessary to emphasize that there are many important aspects of follow-up in addition to detection of recurrence, and this must lead to proposals to change the way follow-up care is delivered.

Abstract

Colorectal cancer represents a paradigmatic model of inflammatory carcinogenesis accompanied by the production of several kinds of tumor-associated autoantibodies (TAABs). The specific aim of this study is to define the clinical impact of the presence of non-specific circulating TAABs in a cohort of cancer patients and to establish whether significant differences were present between colorectal cancer and cancers at other sites. For this aim a prospective study was developed and a five-year survival analysis performed. Indirect immunofluorescence on rat tissues for non-organ specific autoantibodies (NOSAs: liver-kidney-stomach), on rat colon substrates (colon-related autoantibodies, CAAs) and on HEp-2 cell lines was performed. NOSA positivity was more frequent in patients with colorectal cancer than in those with cancer at other sites. Survival analysis demonstrated a significantly worse prognosis in cancer patients positive for TAABs. CAA positivity is a predictor of survival, independently from the presence of comorbidities, and HEp-2 reactivity was a strong predictor of survival in a stepwise Cox-regression model, including stage at diagnosis. Overall overproduction of TAABs is associated with advanced oncological disease, the presence of metastasis, and poorer prognosis of cancer patients.

Human Dental Pulp Stem Cells Modulate Cytokine Production in vitro by Peripheral Blood Mononuclear Cells From Coronavirus Disease 2019 Patients

A subset of patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) developed a condition of hyper-inflammation, which can cause multi-organ damage and the more severe forms of coronavirus disease 2019 (COVID-19). Mesenchymal stem cells (MSCs) can promote tissue regeneration and modulate immune responses and, thus, have the rational requirements to be used to counteract SARS-CoV-2-induced pneumonia and hyper-inflammation. The aim of the present study was to gain insight into possible mechanisms of action of MSCs obtained from human dental pulp [dental pulp stem cells (DPSCs)] in COVID-19 patients. We investigated the concentrations of 18 cytokines in supernatants of peripheral blood mononuclear cells (PBMCs) obtained from COVID-19 patients cultured in vitro alone and in contact with DPSCs. The modulation of cytokines in PBMCs was confirmed by real-time PCR. IL-6 was the sole cytokine detected in supernatants of DPSCs. In resting conditions, co-culture increased IL-1β, IL-2, IL-5, IL-6, IL-10, IL-18, TNFα, and granulocyte macrophage colony-stimulating factor (GM-CSF) levels. When PBMCs were activated with anti-CD3/CD28 antibody-coated beads, co-culture increased IL-6 and GM-CSF, whereas it decreased IFNγ, TNFα, IL-2, IL-5, IL-9, IL-10, IL-12 (p70), IL-17A, IL-18, IL-21, IL-23, and IL-27 levels. Concentrations of IL-1β, IL-4, IL-13, and IL-22 were not affected. The comparison of cytokine concentrations in supernatants of PBMCs from COVID-19 patients vs. healthy subjects revealed lower concentrations of IL-10 and higher concentrations of IL-18 in supernatants of CD3/CD28-activated PBMCs from COVID-19 patients. Results are explorative but indicate that DPSCs can modulate the production of cytokines deregulated in COVID-19 patients, supporting their potential use in COVID-19.

Evaluation of Antimicrobial Effect of Air-Polishing Treatments and Their Influence on Human Dental Pulp Stem Cells Seeded on Titanium Disks

Dental implants are one of the most frequently used treatment options for tooth replacement, and titanium is the metal of choice due to its demonstrated superiority in resisting corrosion, lack of allergic reactions and mechanical strength. Surface roughness of titanium implants favors the osseointegration process; nevertheless, its topography may provide a suitable substrate for bacterial biofilm deposition, causing peri-implantitis and leading to implant failure. Subgingival prophylaxis treatments with cleansing powders aimed to remove the bacterial accumulation are under investigation. Two different air-polishing powders—glycine and tagatose—were assayed for their cleaning and antimicrobial potential against a Pseudomonas biofilm and for their effects on human dental pulp stem cells (hDPSCs), seeded on sandblasted titanium disks. Immunofluorescence analyses were carried out to evaluate cell adhesion, proliferation, stemness and osteogenic differentiation. The results demonstrate that both the powders have a great in vitro cleaning potential in the early period and do not show any negative effects during hDPSCs osteogenic differentiation process, suggesting their suitability for enhancing the biocompatibility of titanium implants. Our data suggest that the evaluated cleansing systems reduce microbial contamination and allow us to propose tagatose as an adequate alternative to the gold standard glycine for the air-polishing prophylaxis treatment.

Effects of a Novel Bioactive Glass Composition on Biological Properties of Human Dental Pulp Stem Cells

Functional reconstruction of bone defects represents a clinical challenge in the regenerative medicine field, which targets tissue repair following traumatic injuries and disease-related bone deficiencies. In this regard, the optimal biomaterial should be safe, biocompatible and tailored in order to promote the activation of host progenitor cells towards bone repair. Bioactive glasses might be suitable biomaterials due to their composition being able to induce the host healing response and, eventually, anti-bacterial properties. In this study we investigated whether and how an innovative bioactive glass composition, called BGMS10, may affect cell adhesion, morphology, proliferation, immunomodulation and osteogenic differentiation of human dental pulp stem cells (hDPSCs). When cultured on BGMS10, hDPSCs maintained their proliferation rate and typical fibroblast-like morphology, showing the expression of stemness markers STRO-1 and c-Kit. Moreover, the expression of FasL, a key molecule in mediating immunomodulation effects of hDPSCs, was maintained. BGMS10 also proved to trigger osteogenic commitment of hDPSCs, as confirmed by the activation of bone-related transcription factors RUNX2 and Osx and the ongoing deposition of extracellular matrix supported by the expression of OPN and OCN. Our findings suggest that BGMS10 not only maintains the typical biological and immunomodulatory properties of hDPSCs but also favors the osteogenic commitment.

Protective Effects of Borago officinalis (Borago) on Cold Restraint Stress-Induced Gastric Ulcers in Rats: A Pilot Study

Stress is a typical body's natural defense to a generic physical or psychic change. A specific linking mechanism between ulcer onset and psycho-physical stress prolonged exposure has been reported. We decided to investigate the possible effects of Borago officinalis L. (Borago) in preventing physical (stress)-induced gastric ulcers in a rat model. Eighty male Sprague-Dawley rats were randomly divided into 16 groups, pretreated with a control solution, omeprazole (20 mg/kg), Borago methanolic extract (25, 50, 100, 250, and 500 mg/kg), Borago organic extract (50, 100, 250, and 500 mg/kg), Borago aqueous extract (5, 10, 20, 30, and 40 mg/kg), and D(-)-2-Amino-5-phosphonovaleric acid (AP5) (25 mg/kg) and kept in stressful conditions such as water immersion and restraint-induced stress ulcers. The animals were sacrificed and their stomach scored for the severity and the number of gastric ulcers. Methanolic extract (500 mg/kg) significantly reduced both ulcer parameters (^***p < 0.001 and ^**p < 0.01, respectively). Aqueous and organic extract significantly decreased severity score at 5 and 10 mg/kg (^**p < 0.01 and ^***p < 0.001, respectively), and at 250 and 500 mg/kg (^***p < 0.001), respectively, while gastric ulcers' resulted number significantly reduced only at 10 mg/kg (^*p < 0.05) and at 500 mg/kg (^**p < 0.01), respectively. On the other hand, aqueous extract significantly increased the mucosal gastric content of cAMP (^*p < 0.05) and NR2A and NR2B subunits (^*p < 0.05 and ^**p < 0.01, respectively) at 5 mg/kg. Organic extract showed also a significant cytotoxic effect at 500 and 1,000 mg/kg with a 3T3 cell viability reduction of 43.6% (^**p < 0.01) and 92.1% (^***p < 0.001), respectively. Borago aqueous extract at 10 mg/kg could be considered as a potential protective agent against stress-induced ulcers, and it is reasonable to possibly ascribe such protective activity to a modulation of the NR2A and NR2B subunit expression.

AB0039 ROLE OF MESENCHYMAL STEM CELLS ISOLATED FROM DENTAL PULP (DPSCS) IN IMMUNOREGULATION PROCESSES MEDIATED BY PROGRAMMED DEATH-LIGAND 1 (PD-L1)

Background:

Stem cells isolated from dental pulp (DPSCs) are characterized by a high rate of proliferation, low immunogenicity and a high ability to differentiate in different lineages (i.e. osteogenic, chondrogenic, adipogenic, myogenic and neural commitment). Their multipotency can be attributed to the peculiar embryological origin from the neural crest. DPSCs represent a promising stem cell resource since they hold a low ethical impact and can be easily isolated through routine dental procedures. These cells own immuno-modulatory properties, exerted through the activation of different mechanisms, including the Fas / FasL pathway, as well as through the release of soluble factors. Currently, other molecular mechanisms are under consideration such as PD-1 / PD-L1 (Programmed Death 1 and its Ligand) which are supposed to be involved in the induction and / or maintenance of immune tolerance.

Objectives:

The aim of this research was to investigate whether the stimulation of PD-L1 in DPSCs can affect the immunomodulatory effects of these stem cells on peripheral blood mononuclear cells (PBMCs). Furthermore, the expression of PD-L1 was also assayed after the induction of osteogenic differentiation of DPSCs in order to evaluate a possible application of DPSCs in autoimmune inflammatory osteo-erosive diseases.

Methods:

Immuno-selection was performed on DPSCs, isolated from waste material, against the stemness markers c-Kit and STRO-1, to obtain a pure stem cell population. Then, STRO-1+/c-Kit+ DPSCs, were co-cultured either directly and indirectly with peripheral blood mononuclear cells (PBMCs) from healthy adult donors, previously activated by anti-CD3 and anti-CD28 antibodies. Co-cultures of PBMCs with amniotic fluid stem cells (AFSCs) and bone marrow mesenchymal stem cells (BM-MSCs) were also set up. The expression of PD-1 in PBMCs as well as of PD-L1 in DPSCs, AFSCs, BM-MSCs and PBMCs, was evaluated by Western Blot (WB) and immunofluorescence (IF) analyses, before and after osteogenic differentiation. Osteogenic differentiation of DPSCs, after 30 days of induction, was verified by IF and WB, of osteopontin, osteocalcin and RUNX2 markers. Interleukin-2 (IL-2) expression levels in PBMCs were analyzed by Real-Time PCR analysis.

Results:

Our data highlight that, after direct and indirect co-culture with activated PBMCs, PD-L1 expression was up-regulated not only in DPSCs, but also in BM-MSCs and AFSCs (Figure 1), thus suggesting that 1) this is a common ability of mesenchymal stem cells and 2) this event can be also mediated by soluble factors release. Moreover, when evaluating the effects of DPSCs co-culture on PBMCs an increased expression of cleaved caspase 3 was observed, together with a decreased expression of IL-2 - a growth factor essential for the proliferation and survival of T cells (Figure 2). These findings showed how DPSCs can modulate the immune system by PD-L1 up-regulation. On the other hand, it is noteworthy that, after reaching osteogenic commitment, DPSCs down-regulated the expression of PD-L1, allowing to hypothesize that PD-L1 expression is strictly related to the maintenance of stemness.

Figure 1.Figure 2.

Conclusion:

Taken together, our findings suggest that the expression of PD-L1 in DPSCs is involved in the modulation of immune response and pave the way for further investigations on the role of PD-1/PD-L1 pathway in controlling inflammation and immune response when applied to the treatment of autoimmune inflammatory diseases.

References:

[1]Keir ME, et al. PD-1 and its ligands in tolerance and immunity. Annu Rev Immunol. 2008

Disclosure of Interests:

None declared

Modulation of Cell Death and Promotion of Chondrogenic Differentiation by Fas/FasL in Human Dental Pulp Stem Cells (hDPSCs)

Human dental pulp stem cells (hDPSCs) are characterized by high proliferation rate, the multi-differentiation ability and, notably, low immunogenicity and immunomodulatory properties exerted through different mechanisms including Fas/FasL pathway. Despite their multipotency, hDPSCs require particular conditions to achieve chondrogenic differentiation. This might be due to the perivascular localization and the expression of angiogenic marker under standard culture conditions. FasL stimulation was able to promote the early induction of chondrogenic commitment and to lead the differentiation at later times. Interestingly, the expression of angiogenic marker was reduced by FasL stimulation without activating the extrinsic apoptotic pathway in standard culture conditions. In conclusion, these findings highlight the peculiar embryological origin of hDPSCs and provide further insights on their biological properties. Therefore, Fas/FasL pathway not only is involved in determining the immunomodulatory properties, but also is implicated in supporting the chondrogenic commitment of hDPSCs.

Neural crest derived stem cells from dental pulp and tooth-associated stem cells for peripheral nerve regeneration

The peripheral nerve injuries, representing some of the most common types of traumatic lesions affecting the nervous system, are highly invalidating for the patients besides being a huge social burden. Although peripheral nervous system owns a higher regenerative capacity than does central nervous system, mostly depending on Schwann cells intervention in injury repair, several factors determine the extent of functional outcome after healing. Based on the injury type, different therapeutic approaches have been investigated so far. Nerve grafting and Schwann cell transplantation have represented the gold standard treatment for peripheral nerve injuries, however these approaches own limitations, such as scarce donor nerve availability and donor site morbidity. Cell based therapies might provide a suitable tool for peripheral nerve regeneration, in fact, the ability of different stem cell types to differentiate towards Schwann cells in combination with the use of different scaffolds have been widely investigated in animal models of peripheral nerve injuries in the last decade. Dental pulp is a promising cell source for regenerative medicine, because of the ease of isolation procedures, stem cell proliferation and multipotency abilities, which are due to the embryological origin from neural crest. In this article we review the literature concerning the application of tooth derived stem cell populations combined with different conduits to peripheral nerve injuries animal models, highlighting their regenerative contribution exerted through either glial differentiation and neuroprotective/neurotrophic effects on the host tissue.

Regenerative potential of human dental pulp stem cells in the treatment of stress urinary incontinence: In vitro and in vivo study

Objectives

To evaluate the regenerative potential of human dental pulp stem cells (hDPSCs) in an animal model of stress urinary incontinence (SUI). SUI, an involuntary leakage of urine, is due to physical stress involving an increase in bladder pressure and a damage of external urethral sphincter affecting muscles and nerves. Conventional therapies can only relieve the symptoms. Human DPSCs are characterized by peculiar stemness and immunomodulatory properties and might provide an alternative tool for SUI therapy.

Materials and methods

In vitro phase: hDPSCs were induced towards the myogenic commitment following a 24 hours pre‐conditioning with 5‐aza‐2′‐deoxycytidine (5‐Aza), then differentiation was evaluated. In vivo phase: pudendal nerve was transected in female rats to induce stress urinary incontinence; then, pre‐differentiated hDPSCs were injected in the striated urethral sphincter. Four weeks later, urethral sphincter regeneration was assayed through histological, functional and immunohistochemical analyses.

Results

Human DPSCs were able to commit towards myogenic lineage in vitro and, four weeks after cell injection, hDPSCs engrafted in the external urethral sphincter whose thickness was almost recovered, committed towards myogenic lineage in vivo, promoted vascularization and an appreciable recovery of the continence. Moreover, hDPSCs were detected within the nerve, suggesting their participation in repair of transected nerve.

Conclusions

These promising data and further investigations on immunomodulatory abilities of hDPSCs would allow to make them a potential tool for alternative therapies of SUI.

Mitochondrial functionality and metabolism in T cells from progressive multiple sclerosis patients

Patients with primary progressive (PP) and secondary progressive (SP) forms of multiple sclerosis (MS) exhibit a sustained increase in the number of Th1, T cytotoxic type-1 and Th17 cells in peripheral blood, suggesting that the progressive phase is characterized by a permanent peripheral immune activation. As T cell functionality and activation are strictly connected to their metabolic profile, we investigated the mitochondrial functionality and metabolic changes of T cell subpopulations in a cohort of progressive MS patients. T cells from progressive patients were characterized by low proliferation and increase of terminally differentiated/exhausted cells. T cells from PP patients showed lower Oxygen Consumption Rate and Extracellular Acidification Rate, lower mitochondrial mass, membrane potential and respiration than those of SP patients, a downregulation of transcription factors supporting respiration and higher tendency to shift towards glycolysis upon stimulation. Furthermore, PP effector memory T cells were characterized by higher Glucose transporter -1 levels and a higher expression of glycolytic-supporting genes if compared to SP patients. Overall, our data suggest that profound differences exist in the phenotypic and metabolic features of T cells from PP and SP patients, even though the two clinical phenotypes are considered part of the same disease spectrum.

In vitro Engineering of a Skin Substitute Based on Adipose-Derived Stem Cells

In the field of wound healing, stem cell-based strategies are gaining importance for their regenerative potential. Adipose-derived stem cells (ADSCs) are a particular subset of mesenchymal stem cells present in the stromal-vascular fraction of the adipose tissue, today considered very attractive for their relative abundance and accessibility in the human body. However, ADSCs are still not routinely used in normal clinical practice. Several studies have also reported ADSC transplantation in association with biomaterials in an attempt to enhance the local retention and growth rate of the cells. The aim of our study was to evaluate the ability of ADSCs to build a dermal scaffold to be potentially used as a dermal substitute in the field of wound healing, with optimal biocompatibility and mechanical properties. ADSCs were defined as CD90-, CD73-, and CD105-positive cells. ADSCs turned out to be capable of secreting all the main components of the extracellular matrix (ECM) upon stimulation, thus efficiently producing a collagen and fibronectin-containing dermal matrix. We also checked whether the ADSC-produced dermal scaffold could be seeded with keratinocytes. The scaffolding material directly produced by ADSCs has several advantages when compared to the commercially available ones: it is easily obtained from the patients and it is 100% biocompatible and supports cell-ECM interaction. Moreover, it represents a possible powerful therapeutic tool for patients with chronic ulcers since it appears to be potentially grafted with keratinocytes layers, thus bypassing the classical two-step grafting procedure.

Fabrication and characterization of biomimetic hydroxyapatite thin films for bone implants by direct ablation of a biogenic source

Biomimetic bone apatite coatings were realized for the first time by the novel Ionized Jet Deposition technique. Bone coatings were deposited on titanium alloy substrates by pulsed electron ablation of deproteinized bovine bone shafts in order to resemble bone apatite as closely as possible. The composition, morphology and mechanical properties of the coatings were characterized by GI-XRD, FT-IR, SEM-EDS, AFM, contact angle measurements, micro-scratch and screw-insertion tests. Different post-treatment annealing conditions (from 350 °C to 425 °C) were investigated. Bone apatite coatings exhibited a nanostructured surface morphology and a composition closely resembling that of the deposition target (i.e. natural bone apatite), also regarding the presence of magnesium and sodium ions. Crystallinity and composition of the coatings were strongly influenced by annealing temperature and duration; in particular, upon annealing at 400 °C and above, a crystallinity similar to that of bone was achieved. Finally, adhesion to the titanium substrate and hydrophilicity were significantly enhanced upon annealing, all characteristics being known to have a strong positive impact on promoting host cells attachment, proliferation and differentiation.

Ex vivo fluorescence confocal microscopy for intraoperative, real-time diagnosis of cutaneous inflammatory diseases: A preliminary study

Ex vivo fluorescence confocal microscopy (FCM) is an innovative imaging tool that can be used intraoperatively to obtain real-time images of untreated excised tissue with almost histologic resolution. As inflammatory diseases often share overlapping clinical features, histopathology evaluation is required for dubious cases, delaying definitive diagnoses, and therefore therapy. This study identifies key-features at ex vivo FCM for differential diagnoses of cutaneous inflammatory diseases, in particular, psoriasis, eczema, lichen planus and discoid lupus erythematosus. Retrospective ex vivo FCM and histological evaluations with relevant diagnoses were correlated with prospectively reported histopathologic diagnoses, to evaluate agreement and the level of expertise required for correct diagnoses. We demonstrated that ex vivo FCM enabled the distinction of the main inflammatory features in most cases, providing a substantial concordance to histopathologic diagnoses. Moreover, ex vivo FCM and histological evaluations reached a substantial agreement with histopathologic diagnoses both for all raters and for each operator. After a yet to be defined learning curve, these preliminary results suggest that dermatologists may be able to satisfactorily interpret ex vivo FCM images for correct real-time diagnoses. Despite some limitations mainly related to the equipment of FCM with a single objective lens, our study suggests that ex vivo FCM seems a promising tool in assisting diagnoses of cutaneous inflammatory lesions, with a level of accuracy quite close to that offered by histopathology. This is the first study to investigate ex vivo FCM application in cutaneous inflammatory lesions, and to evaluate the diagnostic capability of this technology.

LonP1 Differently Modulates Mitochondrial Function and Bioenergetics of Primary Versus Metastatic Colon Cancer Cells

Mitochondrial Lon protease (LonP1) is a multi-function enzyme that regulates mitochondrial functions in several human malignancies, including colorectal cancer (CRC). The mechanism(s) by which LonP1 contributes to colorectal carcinogenesis is not fully understood. We found that silencing LonP1 leads to severe mitochondrial impairment and apoptosis in colon cancer cells. Here, we investigate the role of LonP1 in mitochondrial functions, metabolism, and epithelial-mesenchymal transition (EMT) in colon tumor cells and in metastasis. LonP1 was almost absent in normal mucosa, gradually increased from aberrant crypt foci to adenoma, and was most abundant in CRC. Moreover, LonP1 was preferentially upregulated in colorectal samples with mutated p53 or nuclear β-catenin, and its overexpression led to increased levels of β-catenin and decreased levels of E-cadherin, key proteins in EMT, in vitro. LonP1 upregulation also induced opposite changes in oxidative phosphorylation, glycolysis, and pentose pathway in SW480 primary colon tumor cells when compared to SW620 metastatic colon cancer cells. In conclusion, basal LonP1 expression is essential for normal mitochondrial function, and increased LonP1 levels in SW480 and SW620 cells induce a metabolic shift toward glycolysis, leading to EMT.

Use of a 3D Floating Sphere Culture System to Maintain the Neural Crest-Related Properties of Human Dental Pulp Stem Cells

Human dental pulp is considered an interesting source of adult stem cells, due to the low-invasive isolation procedures, high content of stem cells and its peculiar embryological origin from neural crest. Based on our previous findings, a dental pulp stem cells sub-population, enriched for the expression of STRO-1, c-Kit, and CD34, showed a higher neural commitment. However, their biological properties were compromised when cells were cultured in adherent standard conditions. The aim of this study was to evaluate the ability of three dimensional floating spheres to preserve embryological and biological properties of this sub-population. In addition, the expression of the inwardly rectifying potassium channel Kir4.1, Fas and FasL was investigated in 3D-sphere derived hDPSCs. Our data showed that 3D sphere-derived hDPSCs maintained their fibroblast-like morphology, preserved stemness markers expression and proliferative capability. The expression of neural crest markers and Kir4.1 was observed in undifferentiated hDPSCs, furthermore this culture system also preserved hDPSCs differentiation potential. The expression of Fas and FasL was observed in undifferentiated hDPSCs derived from sphere culture and, noteworthy, FasL was maintained even after the neurogenic commitment was reached, with a significantly higher expression compared to osteogenic and myogenic commitments. These data demonstrate that 3D sphere culture provides a favorable micro-environment for neural crest-derived hDPSCs to preserve their biological properties.

Osteogenic Differentiation of hDPSCs on Biogenic Bone Apatite Thin Films

A previous study reported the structural characterization of biogenic apatite (BAp) thin films realized by a pulsed electron deposition system by ablation of deproteinized bovine bone. Thin films annealed at 400°C exhibited composition and crystallinity degree very close to those of biogenic apatite; this affinity is crucial for obtaining faster osseointegration compared to conventional, thick hydroxyapatite (HA) coatings, for both orthopedics and dentistry. Here, we investigated the adhesion, proliferation, and osteogenic differentiation of human dental pulp stem cells (hDPCS) on as-deposited and heat-treated BAp and stoichiometric HA. First, we showed that heat-treated BAp films can significantly promote hDPSC adhesion and proliferation. Moreover, hDPSCs, while initially maintaining the typical fibroblast-like morphology and stemness surface markers, later started expressing osteogenic markers such as Runx-2 and OSX. Noteworthy, when cultured in an osteogenic medium on annealed BAp films, hDPSCs were also able to reach a more mature and terminal commitment, with respect to HA and as-deposited films. Our findings suggest that annealed BAp films not only preserve the typical biological properties of stemness of, hDPSCs but also improve their ability of osteogenic commitment.

Human dental pulp stem cells expressing STRO-1, c-kit and CD34 markers in peripheral nerve regeneration

Peripheral nerve injuries are a commonly encountered clinical problem and often result in long-term functional defects. The application of stem cells able to differentiate in Schwann cell-like cells in vitro and in vivo, could represent an attractive therapeutic approach for the treatment of nerve injuries. Further, stem cells sources sharing the same embryological origin as Schwann cells might be considered a suitable tool. The aim of this study was to demonstrate the ability of a neuroectodermal subpopulation of human STRO-1⁺ /c-Kit⁺ /CD34⁺ DPSCs, expressing P75^NTR , nestin and SOX-10, to differentiate into Schwann cell-like cells in vitro and to promote axonal regeneration in vivo, which led to functional recovery as measured by sustained gait improvement, in animal rat model of peripheral nerve injury. Transplanted human dental pulp stem cells (hDPSCs) engrafted into sciatic nerve defect, as revealed by the positive staining against human nuclei, showed the expression of typical Schwann cells markers, S100b and, noteworthy, a significant number of myelinated axons was detected. Moreover, hDPSCs promoted axonal regeneration from proximal to distal stumps 1 month after transplantation. This study demonstrates that STRO-1⁺ /c-Kit⁺ /CD34⁺ hDPSCs, associated with neural crest derivation, represent a promising source of stem cells for the treatment of demyelinating disorders and might provide a valid alternative tool for future clinical applications to achieve functional recovery after injury or peripheral neuropathies besides minimizing ethical issues. Copyright © 2016 John Wiley & Sons, Ltd.

Inhibition of Lon protease by triterpenoids alters mitochondria and is associated to cell death in human cancer cells

Mitochondrial Lon protease (Lon) regulates several mitochondrial functions, and is inhibited by the anticancer molecule triterpenoid 2-cyano-3, 12-dioxooleana-1,9(11)-dien-28-oic acid (CDDO), or by its C-28 methyl ester derivative (CDDO-Me). To analyze the mechanism of action of triterpenoids, we investigated intramitochondrial reactive oxygen species (ROS), mitochondrial membrane potential, mitochondrial mass, mitochondrial dynamics and morphology, and Lon proteolytic activity in RKO human colon cancer cells, in HepG2 hepatocarcinoma cells and in MCF7 breast carcinoma cells. We found that CDDO and CDDO-Me are potent stressors for mitochondria in cancer cells, rather than normal non-transformed cells. In particular, they: i) cause depolarization; ii) increase mitochondrial ROS, iii) alter mitochondrial morphology and proteins involved in mitochondrial dynamics; iv) affect the levels of Lon and those of aconitase and human transcription factor A, which are targets of Lon activity; v) increase level of protein carbonyls in mitochondria; vi) lead to intrinsic apoptosis. The overexpression of Lon can rescue cells from cell death, providing an additional evidence on the role of Lon in conditions of excessive stress load.

Optimized Cryopreservation and Banking of Human Bone-Marrow Fragments and Stem Cells

Adult mesenchymal stem cells are a promising source for cell therapies and tissue engineering applications. Current procedures for banking of human bone-marrow mesenchymal stem cells (hBM-MSCs) require cell isolation and expansion, and thus the use of large amounts of animal sera. However, animal-derived culture supplements have the potential to trigger infections and severe immune reactions. The aim of this study was to investigate an optimized method for cryopreservation of human bone-marrow fragments for application in cell banking procedures where stem-cell expansion and use are not immediately needed. Whole trabecular fragments enclosing the bone marrow were stored in liquid nitrogen for 1 year in a cryoprotective solution containing a low concentration of dimethyl sulfoxide and a high concentration of human serum (HuS). After thawing, the isolation, colony-forming-unit ability, proliferation, morphology, stemness-related marker expression, cell senescence, apoptosis, and multi-lineage differentiation potential of hBM-MSCs were tested in media containing HuS compared with hBM-MSCs isolated from fresh fragments. Human BM-MSCs isolated from cryopreserved fragments expressed MSC markers until later passages, had a good proliferation rate, and exhibited the capacity to differentiate toward osteogenic, adipogenic, and myogenic lineages similar to hBM-MSCs isolated from fresh fragments. Moreover, the cryopreservation method did not induce cell senescence or cell death. These results imply that minimal processing may be adequate for the banking of tissue samples with no requirement for the immediate isolation and use of hBM-MSCs, thus limiting cost and the risk of contamination, and facilitating banking for clinical use. Furthermore, the use of HuS for cryopreservation and expansion/differentiation has the potential for clinical application in compliance with good manufacturing practice standards.

Stem cells isolated from human dental pulp and amniotic fluid improve skeletal muscle histopathology in mdx/SCID mice

INTRODUCTION

Duchenne muscular dystrophy (DMD), caused by a lack of the functional structural protein dystrophin, leads to severe muscle degeneration where the patients are typically wheelchair-bound and die in their mid-twenties from cardiac or respiratory failure or both. The aim of this study was to investigate the potential of human dental pulp stem cells (hDPSCs) and human amniotic fluid stem cells (hAFSCs) to differentiate toward a skeletal myogenic lineage using several different protocols in order to determine the optimal conditions for achieving myogenic commitment and to subsequently evaluate their contribution in the improvement of the pathological features associated with dystrophic skeletal muscle when intramuscularly injected into mdx/SCID mice, an immune-compromised animal model of DMD.

METHODS

Human DPSCs and AFSCs were differentiated toward myogenic lineage in vitro through the direct co-culture with a myogenic cell line (C2C12 cells) and through a preliminary demethylation treatment with 5-Aza-2'-deoxycytidine (5-Aza), respectively. The commitment and differentiation of both hDPSCs and hAFSCs were evaluated by immunofluorescence and Western blot analysis. Subsequently, hDPSCs and hAFSCs, preliminarily demethylated and pre-differentiated toward a myogenic lineage for 2 weeks, were injected into the dystrophic gastrocnemius muscles of mdx/SCID mice. After 1, 2, and 4 weeks, the gastrocnemius muscles were taken for immunofluorescence and histological analyses.

RESULTS

Both populations of cells engrafted within the host muscle of mdx/SCID mice and through a paracrine effect promoted angiogenesis and reduced fibrosis, which eventually led to an improvement of the histopathology of the dystrophic muscle.

CONCLUSION

This study shows that hAFSCs and hDPSCs represent potential sources of stem cells for translational strategies to improve the histopathology and potentially alleviate the muscle weakness in patients with DMD.

Ferutinin dose-dependent effects on uterus and mammary gland in ovariectomized rats

The present paper completes our recent study on the effects of phytoestrogen ferutinin in preventing osteoporosis and demonstrating the superior osteoprotective effect of a 2 mg/kg/day dose in ovariectomized (OVX) rats, compared to both estrogens and lower (0.5, 1 mg/kg/day) ferutinin doses. Morphological and morphometrical analyses were performed on the effects of different doses of ferutinin administrated for one month on uterus and on mammary gland of Sprague-Dawley OVX rats, evaluated in comparison with the results for estradiol benzoate. To verify whether ferutinin provides protection against uterine and breast cancer, estimations were made of both the amount of cell proliferation (by Ki-67), and the occurrence of apoptosis (by TUNEL), two processes that in unbalanced ratio form the basis for cancer onset. The results suggest that the effects of ferutinin are dose dependent and that a 2 mg/kg/day dose might offer a better protective action against the onset of both breast and uterine carcinoma compared to ferutinin in lower doses or estradiol benzoate, increasing cellular apoptosis in glandular epithelia.

In vitro differentiation into insulin-producing β-cells of stem cells isolated from human amniotic fluid and dental pulp

AIM

To investigate the ability of human amniotic fluid stem cells and human dental pulp stem cells to differentiate into insulin-producing cells.

METHODS

Human amniotic fluid stem cells and human dental pulp stem cells were induced to differentiate into pancreatic β-cells by a multistep protocol. Islet-like structures were assessed in differentiated human amniotic fluid stem cells and human dental pulp stem cells after 21 days of culture by dithizone staining. Pancreatic and duodenal homebox-1, insulin and Glut-2 expression were detected by immunofluorescence and confocal microscopy. Insulin secreted from differentiated cells was tested with SELDI-TOF MS and by enzyme-linked immunosorbent assay.

RESULTS

Human amniotic fluid stem cells and human dental pulp stem cells, after 7 days of differentiation started to form islet-like structures that became evident after 14 days of induction. SELDI-TOF MS analysis, revealed the presence of insulin in the media of differentiated cells at day 14, further confirmed by enzyme-linked immunosorbent assay after 7, 14 and 21 days. Both stem cell types expressed, after differentiation, pancreatic and duodenal homebox-1, insulin and Glut-2 and were positively stained by dithizone. Either the cytosol to nucleus translocation of pancreatic and duodenal homebox-1, either the expression of insulin, are regulated by glucose concentration changes. Day 21 islet-like structures derived from both human amniotic fluid stem cells and human dental pulp stem cell release insulin in a glucose-dependent manner.

CONCLUSION

The present study demonstrates the ability of human amniotic fluid stem cells and human dental pulp stem cell to differentiate into insulin-producing cells, offering a non-pancreatic, low-invasive source of cells for islet regeneration.

Human amniotic fluid-derived and dental pulp-derived stem cells seeded into collagen scaffold repair critical-size bone defects promoting vascularization

Introduction

The main aim of this study is to evaluate potential human stem cells, such as dental pulp stem cells and amniotic fluid stem cells, combined with collagen scaffold to reconstruct critical-size cranial bone defects in an animal model.

Methods

We performed two symmetric full-thickness cranial defects on each parietal region of rats and we replenished them with collagen scaffolds with or without stem cells already seeded into and addressed towards osteogenic lineage in vitro. After 4 and 8 weeks, cranial tissue samples were taken for histological and immunofluorescence analysis.

Results

We observed a new bone formation in all of the samples but the most relevant differences in defect correction were shown by stem cell–collagen samples 4 weeks after implant, suggesting a faster regeneration ability of the combined constructs. The presence of human cells in the newly formed bone was confirmed by confocal analysis with an antibody directed to a human mitochondrial protein. Furthermore, human cells were found to be an essential part of new vessel formation in the scaffold.

Conclusion

These data confirmed the strong potential of bioengineered constructs of stem cell–collagen scaffold for correcting large cranial defects in an animal model and highlighting the role of stem cells in neovascularization during skeletal defect reconstruction.