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Degenerative processes of the intervertebral disc (IVD) and cartilaginous endplate lead to chronic spine pathologies. Several studies speculated on the intrinsic regenerative capacity of degenerated IVD related to the presence of local mesenchymal progenitors. However, a complete characterisation of the resident IVD cell populations, particularly that isolated from the endplate, is lacking. The purpose of the present study was to characterise the gene expression profiles of human nucleus pulposus (NPCs), annulus fibrosus (AFCs) and endplate (EPCs) cells, setting the basis for future studies aimed at identifying the most promising cells for regenerative purposes. Cells isolated from NP, AF and EP were analysed after in vitro expansion for their stemness ability, immunophenotype and gene profiles by large-scale microarray analysis. The three cell populations shared a similar clonogenic, adipogenic and osteogenic potential, as well as an immunophenotype with a pattern resembling that of mesenchymal stem cells. NPCs maintained the greatest chondrogenic potential and shared with EPCs the loss of proliferation capability during expansion. The largest number of selectively highly expressed stemness, chondrogenic/tissue-specific and surface genes was found in AFCs, thus representing the most promising source of tissue-specific expanded cells for the treatment of IVD degeneration.

Background A growing number of clinical trials have shown that regulatory T (Treg) cell transfer may have a favorable effect on the maintenance of self-tolerance and immune homeostasis in different conditions such as graft-versus-host disease (GvHD), solid organ transplantation, type 1 diabetes, and others. In this context, the availability of a robust manufacturing protocol that is able to produce a sufficient number of functional Treg cells represents a fundamental prerequisite for the success of a cell therapy clinical protocol. However, extended workflow guidelines for nonprofit manufacturers are currently lacking. Despite the fact that different successful manufacturing procedures and cell products with excellent safety profiles have been reported from early clinical trials, the selection and expansion protocols for Treg cells vary a lot. The objective of this study was to validate a Good Manufacturing Practice (GMP)-compliant protocol for the production of Treg cells that approaches the whole process with a risk-management methodology, from process design to completion of final product development. High emphasis was given to the description of the quality control (QC) methodologies used for the in-process and release tests (sterility, endotoxin test, mycoplasma, and immunophenotype). Results The GMP-compliant protocol defined in this work allows at least 4.11 × 109 Treg cells to be obtained with an average purity of 95.75 ± 4.38% and can be used in different clinical settings to exploit Treg cell immunomodulatory function. Conclusions These results could be of great use for facilities implementing GMP-compliant cell therapy protocols of these cells for different conditions aimed at restoring the Treg cell number and function, which may slow the progression of certain diseases.

Sporadic cases account for 90–95% of all patients with Parkinson's Disease (PD). Atypical Parkinsonism comprises approximately 20% of all patients with parkinsonism. Progressive Supranuclear Palsy (PSP) belongs to the atypical parkinsonian diseases and is histopathologically classified as a tauopathy. Here, we report that mesenchymal stem cells (MSCs) derived from the bone marrow of patients with PSP exhibit mitochondrial dysfunction in the form of decreased membrane potential and inhibited NADH-dependent respiration. Furthermore, mitochondrial dysfunction in PSP-MSCs led to a significant increase in mitochondrial ROS generation and oxidative stress, which resulted in decrease of major cellular antioxidant GSH. Additionally, higher basal rate of mitochondrial degradation and lower levels of biogenesis were found in PSP-MSCs, together leading to a reduction in mitochondrial mass. This phenotype was biologically relevant to MSC stemness properties, as it heavily impaired their differentiation into adipocytes, which mostly rely on mitochondrial metabolism for their bioenergetic demand. The defect in adipogenic differentiation was detected as a significant impairment of intracellular lipid droplet formation in PSP-MSCs. This result was corroborated at the transcriptional level by a significant reduction of PPARγ and FABP4 expression, two key genes involved in the adipogenic molecular network. Our findings in PSP-MSCs provide new insights into the etiology of ‘idiopathic’ parkinsonism, and confirm that mitochondrial dysfunction is important to the development of parkinsonism, independent of the type of the cell., Graphical abstract fx1, Highlights • PSP pathology leads to inhibition of mitochondrial respiration and decrease mitochondrial membrane potential. • Mitochondrial dysfunction in PSP-MSCs induces ROS generation and oxidative stress. • Higher rate of mitophagy reduces mitochondrial mass in PSP-MSCs. • PSP impairs differentiation properties in MSCs.

In a recent work, our group showed the existence of two distinct mesenchymal stem cell (MSC) subsets within human umbilical cord blood. One less proliferative and short-living (SL-CBMSC), the other with higher growth rate and long-living (LL-CBMSC), and therefore better suited for regenerative medicine applications. We examined whether LL-CBMSC possess peculiar paracrine properties able to affect angiogenesis or inflammatory processes. It was shown for the first time that pro-angiogenic, proliferation-stimulating and tissue repairing factors were released at high level not only as soluble cytokines, but also as mRNA precursors embedded in membrane vesicles. The combination of this primary (proteic factors interacting with surface receptors) and delayed (mRNA transferred and translated via vesicle fusion and cargo release) interaction in endothelial target cells resulted in strong blood vessel induction with the development of capillary-like structures. In addition, LL-CBMSC dynamically modulated their release of pro-angiogenic and anti-inflammatory factors in an in vitro model of damage. In conclusion, LL-CBMSC synthesize and secrete multiple factors that may be attuned in response to the status of the target cell, a crucial requisite when paracrine mechanisms are needed at onset of tissue regeneration.

Mesenchymal stromal cells (MSC) for cellular therapy in European Union are classified as advanced therapy medicinal products (ATMPs), and their production must fulfill the requirements of Good Manufacturing Practice (GMP) rules. Despite their classification as medicinal products is already well recognized, there is still a lack of information and indications to validate methods and to adapt the noncompendial and compendial methods to these peculiar biological products with intrinsic characteristics that differentiate them from classic synthetic or biologic drugs. In the present paper, we present the results of the validation studies performed in the context of MSC development as ATMPs for clinical experimental use. Specifically, we describe the validation policies followed for sterility testing, endotoxins, adventitious viruses, cell count, and immunophenotyping. Our work demonstrates that it is possible to fully validate analytical methods also for ATMPs and that a risk-based approach can fill the gap between the prescription of the available guidelines shaped on traditional medicinal products and the peculiar characteristics of these novel and extremely promising new drugs.

Progressive Supranuclear Palsy (PSP) is a rare neurodegenerative disease whose etiopathogenesis remains elusive. The intraneuronal accumulation of hyperphosphorylated Tau, a pivotal protein in regulating microtubules (MT), leads to include PSP into tauopathies. Pathological hallmarks are well known in neural cells but no word yet if PSP‐linked dysfunctions occur also in other cell types. We focused on bone marrow mesenchymal stromal cells (MSCs) that have recently gained attention for therapeutic interventions due to their anti‐inflammatory, antiapoptotic and trophic properties. Here, we aimed to investigate MSCs biology and to disclose if any disease‐linked defect occurs in this non‐neuronal compartment. First, we found that cells obtained from patients showed altered morphology and growth. Next, Western blotting analysis unravelled the imbalance in α‐tubulin post‐translational modifications and in MT stability. Interestingly, MT mass is significantly decreased in patient cells at baseline and differently changes overtime compared to controls, suggesting their inability to efficiently remodel MT cytoskeleton during ageing in culture. Thus, our results provide the first evidence that defects in MT regulation and stability occur and are detectable in a non‐neuronal compartment in patients with PSP. We suggest that MSCs could be a novel model system for unravelling cellular processes implicated in this neurodegenerative disorder.

Human mesenchymal stem cells (MSCs) are multipotent cells offering valuable hopes for the treatment of degenerative diseases. MSCs can be found among differentiated cells in many tissues and organs but, unfortunately, their phenotypic similarity hinders a robust cell characterization and discrimination from diverse tissue harvests. MicroRNAs (miRNAs) are crucial managers of gene expression with intriguing and still poorly known roles in stem cell maintenance and differentiation. To identify miRNAs that can discriminate among MSCs, we performed a whole-genome comparative miRNA expression profiling analysis on adipose (AD), bone marrow (BM) and cord blood (CB) derived MSCs, all three considered among the most promising in the field of regenerative medicine. miRNA expression patterns were very similar, meeting their extensive phenotypic and functional overlaps. An in-depth comparison of the few most differentially expressed miRNAs allowed the identification of a highly restricted molecular signature consisting of 5 BMMSC, 11 ADMSC and 11 CBMSC specific miRNAs. Functional analysis of their validated targets allowed the identification of an "environmental-niche memory" for BMMSC and an "epithelial" commitment for ADMSC, providing new insights into the molecular mechanisms discriminating between these MSCs, a crucial element to identify the most appropriate stem cell source for clinical application.

Cell-based therapies promise important developments for regenerative medicine purposes. Adipose tissue and the adipogenic process has become central to an increasing number of translational efforts in addition to plastic and reconstructive surgical applications. In recent experimental clinical trials, human mesenchymal stem cells (MSC) have been proven to be well tolerated because of their low immunoreactivity. MSC are multipotent cells found among mature cells in different tissues and organs with the potentiality to differentiate in many cell types, including osteocytes, chondrocytes and adipocytes, thus being a suitable cell source for tissue engineering strategies. We compared the adipogenic potential of MSC originated from two adult sources as fat pads and bone marrow, and from four foetal sources as umbilical cord blood, Wharton's jelly, amniotic fluid and preterm umbilical cord perivascular cells. Surprisingly, adult MSC displayed higher differentiation capacities confirmed by gene expression analysis on a selected panel of adipogenesis-related genes. Further, an in-depth molecular analysis highlighted the early and vigorous activation of the PPARγ transcription factor-cascade in adipose-derived MSC that resulted to be both delayed and reduced in foetal MSC accounting for their lack of adipogenic potential. Thus, MSC show a different degree of phenotypic plasticity depending on the source tissue, that should be taken into consideration for the selection of the most appropriate MSC type for specific tissue regeneration purposes.

In the last years, mesenchymal stem cells (MSCs) have been identified as an attractive cell population in regenerative medicine. In view of future therapeutic applications, the study of specific differentiation-related gene expression is a pivotal prerequisite to define the most appropriate MSC source for clinical translation. In this context, it is crucial to use stable housekeeping genes (HGs) for normalization of qRT-PCR to obtain validated and comparable results. By our knowledge, an exhaustive validation study of HGs comparing MSCs from different sources under various differentiation conditions is still missing. In this pivotal study, we compared the expression levels of 12 genes (ACTB, β2M, EF1alpha, GAPDH, GUSB, PPIA, RPL13A, RPLP0, TBP, UBC, YWHAZ and 18S rRNA) to assess their suitability as HGs in MSCs during adipogenic, osteogenic and chondrogenic differentiation. We demonstrated that many of the most popular HGs including 18S rRNA, B2M and ACTB were inadequate for normalization, whereas TBP/YWHAZ/GUSB were frequently identified among the best performers. Moreover, we showed the dramatic effects of suboptimal HGs choice on the quantification of cell differentiation markers, thus interfering with a reliable comparison of the lineage potential properties among various MSCs. Thus, in the emerging field of regenerative medicine, the identification of the most appropriate MSC source and cell line is so crucial for the treatment of patients that being inaccurate in the first step of the stem cell characterization can bring important consequences for the patients and for the promising potential of stem cell therapy.

Background The trophic, anti-apoptotic and regenerative effects of bone marrow mesenchymal stromal cells (MSC) may reduce neuronal cell loss in neurodegenerative disorders. Methods We used MSC as a novel candidate therapeutic tool in a pilot phase-I study for patients affected by progressive supranuclear palsy (PSP), a rare, severe and no-option form of Parkinsonism. Five patients received the cells by infusion into the cerebral arteries. Effects were assessed using the best available motor function rating scales (UPDRS, Hoehn and Yahr, PSP rating scale), as well as neuropsychological assessments, gait analysis and brain imaging before and after cell administration. Results One year after cell infusion, all treated patients were alive, except one, who died 9 months after the infusion for reasons not related to cell administration or to disease progression (accidental fall). In all treated patients motor function rating scales remained stable for at least six-months during the one-year follow-up. Conclusions We have demonstrated for the first time that MSC administration is feasible in subjects with PSP. In these patients, in whom deterioration of motor function is invariably rapid, we recorded clinical stabilization for at least 6 months. These encouraging results pave the way to the next randomized, placebo-controlled phase-II study that will definitively provide information on the efficacy of this innovative approach. Trial registration ClinicalTrials.gov NCT01824121

Tiziana Montemurro, Mariele Viganò, Silvia Budelli, Elisa Montelatici, Cristiana Lavazza, Luigi Marino, Valentina Parazzi, Lorenza Lazzari, Rosaria GiordanoCell Factory, Unit of Cell Therapy and Cryobiology, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milano, ItalyAbstract: In the 21st century scenario, new therapeutic tools are needed to take up the social and medical challenge posed by the more and more frequent degenerative disorders and by the aging of population. The recent category of advanced therapy medicinal products has been created to comprise cellular, gene therapy, and tissue engineered products, as a new class of drugs. Their manufacture requires the same pharmaceutical framework as for conventional drugs and this means that industrial, large-scale manufacturing process has to be adapted to the peculiar characteristics of cell-containing products. Our hospital took up the challenge of this new path in the early 2000s; and herein we describe the approach we followed to set up a pharmaceutical-grade facility in a public hospital context, with the aim to share the solutions we found to make cell therapy compliant with the requirements for the production and the quality control of a high-standard medicinal product.Keywords: advanced therapy medicinal product, good manufacturing practices, stem cells

Background Bone marrow stem/progenitor cells seem to be effective in liver regeneration after tissue injury. Aim To evaluate the feasibility and safety of the mobilization and reinfusion of CD133+ stem/progenitor cells in patients with end-stage liver disease. Methods Autologous CD133+ stem/progenitor cells, mobilized with granulocyte-colony stimulating factor, were collected by leukapheresis and reinfused at increasing doses through the hepatic artery starting from 5 × 104/kg up to 1 × 106/kg. Results 16 subjects with Model for End-stage Liver Disease (MELD) score between 17 and 25 were enrolled, 14 mobilized an adequate number of CD133+ stem/progenitor cells and 12 were reinfused. No severe adverse events related to the procedure were reported. MELD score significantly worsened during mobilization in Child Turcotte Pugh-C patients. A significant improvement of liver function was observed 2 months after reinfusion (MELD 19.5 vs 16; P = 0.045). Overall, 5 patients underwent liver transplantation within 12 months from reinfusion and 2 died because of progressive liver failure. Conclusions CD133+ stem/progenitor cells reinfusion in patients with end-stage liver disease is feasible and safe. A worsening of liver function was observed during mobilization in Child Turcotte Pugh-C patients. The temporary improvement of MELD score after reinfusion suggests that stem cells therapy may be a “bridge to transplant” approach for these patients.

In regenerative medicine, human cord blood-derived multipotent mesenchymal stromal cells (CBMSCs) stand out for their biological peculiarities demonstrated in in vitro and in vivo preclinical studies. Here, we present our 9-year experience for the consistent isolation of CBMSCs. Although nearly one CB unit out of two retains the potential to give rise to MSC colonies, only 46% of them can be cultured till low passages (P≥4), but one-fourth of those reaches even higher passages (P≥8). Subsequent characterization for morphological, clonal, differentiation, and proliferation properties revealed two divergent CBMSC behaviors. In particular, a cumulative population doublings cut-off (CPD=15) was identified that undoubtedly distinguishes two growth curves, and different degrees of commitment toward osteogenesis were observed. These data clearly show the existence of at least two distinct CBMSC subsets: one mainly short-living and less proliferative (SL-CBMSCs), the other long-living, with higher growth rate, and, very importantly, with significantly (P≤0.01) longer telomere (LL-CBMSCs). Moreover, significant differences in the immunoprofile before seeding were found among CB units giving rise to LL-CBMSCs or SL-CBMSCs or showing no colony formation. Finally, all the aforementioned results provided a peculiar and useful set of parameters potentially predictive for CBMSC culture outcome.

evaluation. The area at risk (AR) was assessed either by Evans blue or by fluorescent microspheres (FMic). IS was expressed as percentage of AR not uptaking TTC. Stem cell engraftment was evaluated at 30 days by immunohistochemistry. Results: Calculation of infarcted area resulted easier, faster and more reliable when using the FMic compared with Evans blue. In many samples, the dye permeated into the tissue colouring the heart in blue and resulting in a difficult identification of non-ischemic area. At the contrary, delimitation of the AR was easier and reproducible when using FMic. Histology showed high quality Hematoxylin&Eosin and α-sarcomeric actin only in hearts injected with FMic. At two days, both tracking methods were reliable. At day 30, cells labelled with the V-CM-Dil were promptly identified, while the GFP signal was dim even when the fluorescence was amplified using anti-GFP antibodies. Conclusions: Our study provides evidences suggesting that the use of FMic represents a better alternative compared with Evans blue for AR/IS quantification. We also demonstrated that lipophilic dyes seem to work better than GFP for cell tracking.

To investigate whether human umbilical cord blood mesenchymal stem cells, a novel source of progenitors with multilineage potential: 1) decrease traumatic brain injury sequelae and restore brain function; 2) are able to survive and home to the lesioned region; and 3) induce relevant changes in the environment in which they are infused.Prospective experimental study.Research laboratory.Male C57Bl/6 mice.Mice were subjected to controlled cortical impact/sham brain injury. At 24 hrs postinjury, human umbilical cord blood mesenchymal stem cells (150,000/5 μL) or phosphate-buffered saline (control group) were infused intracerebroventricularly contralateral to the injured side. Immunosuppression was achieved by cyclosporine A (10 mg/kg intraperitoneally).After controlled cortical impact, human umbilical cord blood mesenchymal stem cell transplantation induced an early and long-lasting improvement in sensorimotor functions assessed by neuroscore and beam walk tests. One month postinjury, human umbilical cord blood mesenchymal stem cell mice showed attenuated learning dysfunction at the Morris water maze and reduced contusion volume compared with controls. Hoechst positive human umbilical cord blood mesenchymal stem cells homed to lesioned tissue as early as 1 wk after injury in 67% of mice and survived in the injured brain up to 5 wks. By 3 days postinjury, cell infusion significantly increased brain-derived neurotrophic factor concentration into the lesioned tissue, restoring its expression close to the levels observed in sham operated mice. By 7 days postinjury, controlled cortical impact human umbilical cord blood mesenchymal stem cell mice showed a nonphagocytic activation of microglia/macrophages as shown by a selective rise (260%) in CD11b staining (a marker of microglia/macrophage activation/recruitment) associated with a decrease (58%) in CD68 (a marker of active phagocytosis). Thirty-five days postinjury, controlled cortical impact human umbilical cord blood mesenchymal stem cell mice showed a decrease of glial fibrillary acidic protein positivity in the scar region compared with control mice.These findings indicate that human umbilical cord blood mesenchymal stem cells stimulate the injured brain and evoke trophic events, microglia/macrophage phenotypical switch, and glial scar inhibitory effects that remodel the brain and lead to significant improvement of neurologic outcome.

Background: Progressive Supranuclear Palsy (PSP) is a sporadic and progressive neurodegenerative disease which belongs to the family of tauopathies and involves both cortical and subcortical structures. No effective therapy is to date available. Methods/design: Autologous bone marrow (BM) mesenchymal stem cells (MSC) from patients affected by different type of parkinsonisms have shown their ability to improve the dopaminergic function in preclinical and clinical models. It is also possible to isolate and expand MSC from the BM of PSP patients with the same proliferation rate and immuphenotypic profile as MSC from healthy donors. BM MSC can be efficiently delivered to the affected brain regions of PSP patients where they can exert their beneficial effects through different mechanisms including the secretion of neurotrophic factors. Here we propose a randomized, placebo-controlled, double-blind phase I clinical trial in patients affected by PSP with MSC delivered via intra-arterial injection. Discussion: To our knowledge, this is the first clinical trial to be applied in a no-option parkinsonism that aims to test the safety and to exploit the properties of autologous mesenchymal stem cells in reducing disease progression. The study has been designed to test the safety of this " first-in-man" approach and to preliminarily explore its efficacy by excluding the placebo effect. Trial registration: NCT01824121

Abstract 4403 Our hospital-based GMP facility, named Cell Factory, built in Milano (Italy) and the first one authorized by the National Drug Agency (AIFA) in 2007, has pioneered innovative manufacturing technologies in order to supply therapeutic clinical development programs. By our group and by others, cord blood (CB) mesenchymal stem cells (MSC) have been already tested both in vitro and in extensive pre-clinical disease models, demonstrating that CBMSC are safe and effective. Therefore, CBMSC are the best candidate product for several clinical trials including neurologic and renal repair (1–3). In this context, our group developed the first off-the-shelf (OTS) bank where CBMSC are expanded and banked in GMP conditions, and now they are available as “a drug”, to be distributed for patient doses, much like an off-the-shelf pharmaceutical product. From informed consent CB donations, CBMSC were grown and expanded in CellSTACK kit that includes devices for a closed-system cell culture (Macopharma) with EMEA-grade Australian FBS and they were manufactured through a multi-step controlled and well-validated process. Cell Factory established this innovative culture approach through sufficient passages to produce hundreds of thousands of potential doses from an individual donor. After culture, our quality control approach has been designed to ensure that controls are implemented and completed satisfactorily during manufacturing operations, and that developed procedures and specifications are appropriate and followed, including those performed by contract testing laboratories. In fact, at each step and at the end of the production process before cryopreservation, CBMSC were analyzed and qualified according to pre-established criteria (cell count, viability, extensive immunophenotype, CFU-F, karyotype, CGHArray, telomerase activity, sterility, mycoplasma and endotoxin assays) to ensure that a consistent, well characterized product candidate is produced. The same CBMSC batches can be provided for pre-clinical testing and for further validations to prepare the investigational medicinal product dossier (IMPD) for each clinical trial approvals. Now these GMP batches of CBMSC are cryopreserved and available in our OTS CBMSC bank in different cell doses to comply any kind of medical needs. Products are provided under specific contract conditions developed with the clinical centers. (Contact: cellfactorypoliclinico@gmail.com) Disclosures: No relevant conflicts of interest to declare.

Abstract 4446 Hematopoietic stem and progenitor cells are routinely used in onco-hematological applications as consolidated approaches. Recently, these cells have been exploited also for their non-hematopoietic potential in the novel field of regenerative medicine. In fact, several clinical trials are already ongoing in the cardiovascular field, and more and more innovative applications, such as in liver disorders, are emerging to treat patients for whom no other efficient therapies are available. In Europe, the preparation of hematopoietic cells for non-hematopoietic applications must comply to medicinal products current good manufacturing practices (cGMP) and thus, the production process and the analytical methods applied in quality controls must be validated in order to demonstrate standardization and compliance with pre-defined specifications. In our hospital-based GMP facility, named Cell Factory, the first one authorized by the National Drug Agency, we have several processes ongoing for different clinical experimental trials. In particular, we produce CD133+ cells from leukapheresis (AF) products for liver chronic disease and bone marrow (BM) CD133+ cells for cardiovascular repair, strictly following the GMP rules governing medicinal product and we validated both processes as herein reported. In our hands, AF and BM need different approaches to improve the purity of the final cell product that is crucially important to have consistent clinical results. In fact, BM requires an efficient erythrocyte depletion that we obtained by optimizing a centrifugation based separation system, before the CliniMacs (Miltenyi, Gladbach, Germany) immunomagnetic purification. To validate the aseptic technique, three runs of specific media-fill protocols were set up. Finally, to validate the defined protocol, three runs of validation were performed in our class B facility for both procedures with all the quality controls on “in process” as well as on final products. BM samples from 3 patients who underwent sternotomy for by-pass surgery were collected after informed consent and processed as previously described. The results of the three validation runs were consistent in: cell dose >2×106 (2.54×106, 2.81×106 and 2.62×106), purity >70% (87.5%, 97.4% and 93.6%), viability >70% (88.5%, 90.6% and 96.4%), no growth for sterility and endotoxin AF samples from 3 patients who underwent mobilized standard-volume leukapheresis were collected and processed. The results of validation processes were consistent in: cell dose >100×106 (181×106, 138.5×106 and 178.3×106), purity >80% (91%, 90% and 92%), viability >80% (89%, 93% and 95%), for sterility no growth and for endotoxin In conclusion, all the end-points were reached and currently the cell products are provided to different clinical sites as investigational new drug, approved by the national competent authority. These products, as well as other cellular therapy products, are available upon request at our facility for experimental clinical applications (www.cellfactorymilano.com). Disclosures: No relevant conflicts of interest to declare.

Abstract 2588 Mesenchymal stem cells (MC) represent a promising population for regenerative medicine. Recently, their presence has been documented not only in bone marrow, but also in cord blood (CB), an attractive stem cell source with no ethical controversy. In this study, we investigated if CB could represent a new therapeutic tool for the treatment of severe vascular diseases. We first validated a negative immunoselection approach using a cocktail of antibodies that targets and reduces erythroid components in order to efficiently isolate low-potential (lp)-CBMSC (46% of isolation efficiency) and high-potential (hp)-CBMSC (8.1% of isolation efficiency). Specific aim of this study was to investigate the proangiogenic effect of hp-CBMSC for endothelial regenerative purposes. Previous experiments had shown that lp-CBMSC are able to grow until passage 4–5 only, with a lower differentiation rate as compared to the hp-CBMSC, therefore we used hp-CBMS. First, they were induced towards the endothelial lineage by growing them in endothelial medium supplemented with 5% FBS, 100 ng/ml Vascular Endothelial Growth Factor (VEGF) and 50 ng/ml Endothelial Growth Factor (EGF) in 24-well cell culture plates coated with fibronectin. After 3 weeks of induction, the ability of induced-cells to self-organize into capillary-like structures in the presence of basement membrane matrix was analyzed. Human umbilical vein endothelial cells (labeled with green fluorescent dye PKH67) were co-cultured with induced (A) or non-induced (B) hp-CBMSC (labeled with red fluorescent dye PKH26) in the presence of hp-CBMSC conditioned media (supernatant collected from hp-CBMSC cell culture). Interestingly, the tube formation was observed only in the presence of induced-hp-CBMSC (A) where the contribution of the endothelial (green) and mesenchymal (red) compartment in the vascular network was extremely clear and evident. In addition, to evaluate whether there was a possible endothelial contribution of the conditioned medium released by the non-induced-hp-CBMSC, an angiokit assay (Angiokit, TCS CellWorks Ltd) was performed. A strong tube formation was observed and the anastomosis-like structure was confirmed by the expression of CD31 and Von Willebrand Factor (DAB staining) in immunocytochemistry. The next step was to identify the factors released in the conditioned medium and in fact several angiogenic factors were found: HB-EGF 13.5 (8.7 – 16.7); HGF 22.4 (16.3 – 39.1); FGF 10.6 (7.0 – 13.5); VEGF 471.3 (369.3 – 590.0) (the results are expressed as median (and range) pg/mL and normalized per 1×106 seeded cells) using a cytokine array (Searchlight Multiplex Immunoassay Kits). The work is still ongoing for the quantification of the endothelial gene expression by real-time PCR for some angiogenic genes including: angiopoietin-2, the adhesion molecules intercellular adhesion molecule (ICAM)-1, vascular endothelium-selectin (E-selectin), VCAM1 and VEGF-A in the induced versus the non-induced hp-CBMSC. In conclusion, our promising results suggest that hp-CBMSC can be considered as endothelial “drug stores” and are extremely promising paracrine effectors that could be exploited in future clinical applications for endothelial tissue regeneration. Disclosures: No relevant conflicts of interest to declare.

Advanced therapy medicinal products represent a new generation of medicinal products for regenerative medicine. Since the implementation of the EU regulation for this innovative class of drugs, the academic and hospital institutions have played a central role in their development and manufacture. For these institutions that are not familiar with the industrial context, being in compliance with the pharmaceutical standards is extremely challenging. This report describes how we dealt with some specific issues during our hospital-based GMP experience. Furthermore, we identify as a future perspective the consistent stimulating contribution that a public entity can ensure for advanced therapy medicinal product development and licensing.