Advanced Therapy Medicinal Products as Potential Therapeutic Strategy against COVID-19 and Immune-Related Disorders.

Advanced Therapy Medicinal Products (ATMPs) comprise a heterogenous class of innovative medicinal products, which further require extensive preclinical and clinical assessments before their broader use in the general population [...].

Evaluation of the Regenerative Potential of Platelet-Lysate and Platelet-Poor Plasma Derived from the Cord Blood Units in Corneal Wound Healing Applications: An In Vitro Comparative Study on Corneal Epithelial Cells.

BACKGROUND: Cord blood platelet lysate (CB-PL) and cord blood platelet poor plasma (CB-PPP) have been applied with success in wound healing applications. Pathologies such as Sjogrens's Syndrome (SS) and chronic graft versus host disease (cGVHD) can lead to severe ophthalmology issues. The application of CB-PL and CB-PPP may be strongly considered for damaged cornea healing. This study aimed to the evaluation of the beneficial properties of CB-PL and CB-PPP in corneal wound healing applications. METHODS: Initially, the CB-PL and CB-PPP were produced from donated cord blood units (CBUs), followed by biochemical analysis. Corneal epithelial cells (CECs) were isolated from wistar rats and then cultured with medium containing 20% v/v either of CB-PL or CB-PPP. To define the impact of CB-PL and CB-PPP, biochemical, morphological analysis, scratch-wound assays, and immunoassays in CECs were performed. RESULTS: CB-PL and CB-PPP were characterized by good biochemical parameters, regarding their quality characteristics and biomolecule content. CECs' morphological features did not change after their cultivation with CB-PL or CB-PPP. A scratch wound assay and molecular analysis of CECs expanded with CB-PL indicated higher migratory capacity compared to those cultured with CB-PPP. CONCLUSION: CB-PL and CB-PPP exhibited good properties with respect to cell migration and proliferation, and could be considered an alternative source for eye drop production, to possibly be used in cornea wound healing applications.

Investigating the production of platelet lysate obtained from low volume Cord Blood Units: Focus on growth factor content and regenerative potential.

BACKGROUND: The regenerative potential of platelet lysate (PL) and platelet gel (PG) is mediated by the release of platelets (PLTs) growth factors. The aim of this study was the evaluation of the PL production utilizing low volume single Cord Blood Units (CBUs) and the comparison of the biomolecule content between PLs obtained from intermediate and high volume CBUs. METHODS: CBUs (n = 90) with volumes greater than 50 ml and initial platelet count > 150 × 109/L were used. CBUs were classified into the following groups: group A (50-80 ml), group B (81-110 ml) and group C (111-150 ml). The CBUs were centrifuged twice for the production of the platelet concentrate (PC), which was stored at - 80 °C for at least 48 h. Then, rapidly thawed and the biomolecule content was determined using commercial ELISA kits. The regenerative potential of PLs was evaluated using the scratch wound and in vitro angiogenesis assay. RESULTS: CBPL was produced from low volume single CBUs and contained 3.4 ± 0.3 ×109 PLTs. PL obtained from intermediate and high volume CBUs consisted of 10.2 ±â€¯0.3 and 16.1 ±â€¯0.4 × 109 PLTs. All PL groups were characterized by high biomolecule content. Gap closure was observed within 72 h after the wound assay initiation and the capillary tubes were formed in all study groups. CONCLUSION: This study provided significant evidence regarding the utilization of the low volume CBUs for the production of CB derivatives, thus can serve as healing mediators in regenerative medicine approaches.

Effect of Cord Blood Platelet Gel on wound healing capacity of human Mesenchymal Stromal Cells.

BACKGROUND: Wound healing is a dynamic process, involving the recruitment of growth factors, cytokines, chemokines and cellular populations. Recently, the Cord Blood Platelet Gel (CBPG) has been applied successfully in wound closure and tissue regeneration. Moreover, its proper combination with stem cell populations such as Mesenchymal Stromal Cells (MSCs) may positively improve the wound healing process. Based on the above data, this study aimed to the evaluation of wound healing capacity of MSCs combined with CBPG under in vitro conditions. METHODS: Initially, CBPG was developed from Cord Blood Units (CBUs). The determination of wound healing ability of MSCs was performed using the scratch wound assay. In addition, the morphological features, immunophenotypical characteristics and differentiation capacity of MSCs were evaluated. RESULTS: Scratch wound assay results showed, that CBPG could positively stimulate the MSCs migration. Moreover, MSCs cultured in presence of CBPG were characterized by elongated shape and improved stemness properties as it was indicated by flow cytometric analysis and differentiation process. CONCLUSION: These results clearly showed the beneficial effect of CBPG in combination with MSCs in wound healing. The proper combination of CBPG with stem cells strategy may enhance the healing process in patients with skin erosions.

Vitrified Wharton's jelly tissue as a biomaterial for multiple tissue engineering applications.

Wharton's Jelly (WJ) tissue is a promising biomaterial, for tissue engineering applications. However, its preservation over a long period in order to be readily available needs further optimization. A possible solution could be the vitrification and storage of WJ tissue at low temperatures. The aim of this study is to evaluate the effect of low temperature in the WJ tissue, which was stored at -196 °C, either with the vitrification or conventional cryopreservation methods. WJ tissues were isolated from human umbilical cords, cryopreserved with the above methods and remained for 1 year at -196 °C. Histological analysis of tissue's extracellular matrix (ECM), isolation, and characterization of mesenchymal stromal cells (MSCs) were performed. Histological analysis revealed the presence of ECM components such as collagen, sulfated glycosaminoglycans (sGAGs), and the presence of cell nuclei only in vitrified samples. Furthermore, MSCs were isolated and expanded successfully from vitrified WJ tissues, whereas a few viable cells were obtained from conventionally cryopreserved tissues that were not further expanded. In conclusion, this study indicated the proper preservation of vitrified WJ tissues after 1 year of storage, which eventually could be used in tissue engineering and regenerative medicine approaches.

Good mid-term outcomes after adipose-derived culture-expanded mesenchymal stem cells implantation in knee focal cartilage defects.

PURPOSE: The purpose of the present study was to investigate the mid-term outcomes of a single-stage cell-based procedure in patients with knee focal symptomatic cartilage defects using matrix-induced culture-expanded autologous AD-MSCs. It was hypothesised that the increased number of autologous AD-MSCs after culture expansion is a safe and efficient cartilage repair procedure, which improves overtime chondrogenesis in cartilage lesions METHODS: Twenty-five consecutive patients treated for a symptomatic cartilage defect were prospectively followed for 3 years. The median age of patients was 30.5 (range 16-43) with a median BMI of 23.6 kg/m2 (range 19-29) and an average size of the lesion of 3.5 cm2 (range 2-6). All patients underwent a single-stage procedure consisting in filling each defect with autologous culture-expanded mesenchymal stem cells embedded in a trimmed-to-fit commercially available biodegradable matrix. Pre-operative and post-operative evaluation included knee-related clinical and functional evaluation based on objective and subjective scores at 6, 12, 24 and 36 months and MRI evaluation of the repair tissue using the MOCART score at 12 and 24 months. RESULTS: Clinical outcomes recorded significant improvements (p < 0.05) at the final follow-up compared with baseline as following: all subcategories of KOOS Score, the IKDC subjective from 40.9 (range 20.7-65.6) to 76.9 (range 42-90.3), Tegner Activity Score from 3 (range 2-4) to 4 (range 3-4), VAS for pain from 6 (range 4-8) to 1 (range 0-3). All patients improve significantly their IKDC objective scores. The MRI findings showed complete filling of the defect and integration to the border zone for 65% of the patients. Two patients underwent post-operative biopsies and the histological analysis demonstrated the presence of hyaline-like tissue. CONCLUSIONS: Adipose-derived culture-expanded mesenchymal stem cells were shown to be an efficient and safe single-stage cell-based procedure for symptomatic, full-thickness knee chondral lesions. The findings of the present study demonstrate that all patients presented significant mid-term clinical, functional and radiological improvement. LEVEL OF EVIDENCE: IV.

Matrix-induced adipose-derived mesenchymal stem cells implantation for knee articular cartilage repair. Two years follow-up.

The present study aims to evaluate the efficacy of matrix-induced adipose-derived mesenchymal stem cells (Ad-MSCs) for cartilage repair of focal chondral knee lesions. Twenty patients were initially treated for symptomatic full-thickness chondral defects and then prospectively followed for two years. All patients underwent a single- stage procedure consisting in filling each defect with autologous culture-expanded mesenchymal stem cells embedded in a trimmed-to-fit commercially available biodegradable matrix. Knee-related function was evaluated based on subjective scores given by two self-reported questionnaires (KOOS and IKDC). Data analysis shows significant improvements (p<0.001) in all values. The mean preoperative scores in the subscales of KOOS, as well as in the IKDC subjective score were constantly increased during the follow-up period with statistically significant differences at 6, 12 and 24 months follow-up. The findings of this study indicate that matrix- induced adipose-derived mesenchymal stem cells implantation is an effective and safe single-staged cell-based procedure to manage full-thickness focal chondral lesions of the knee.

Successful short-term cryopreservation of volume-reduced cord blood units in a cryogenic mechanical freezer: effects on cell recovery, viability, and clonogenic potential.

BACKGROUND: Cord blood (CB) units are stored from weeks to years in liquid- or vapor-phase nitrogen until they are used for transplantation. We examined the effects of cryostorage in a mechanical freezer at -150°C on critical quality control variables of CB collections to investigate the possible use of mechanical freezers at -150°C as an alternative to storage in liquid- (or vapor-) phase nitrogen. STUDY DESIGN AND METHODS: A total of 105 CB units were thawed and washed at different time intervals (6, 12, 24, and 36 months). For every thawed CB unit, samples were removed and cell enumeration (total nucleated cells [TNCs], mononuclear cells [MNCs], CD34+, CD133+) was performed. In addition, viability was obtained with the use of flow cytometry, and recoveries were calculated. Also, total absolute colony-forming unit counts were performed and progenitor cell recoveries were studied by clonogenic assays. RESULTS: Significant differences (p < 0.05) were observed in certain variables (TNCs, MNC numbers, viability) when they were examined in relation with time intervals, while others (CD34+, CD133+) were relatively insensitive (p = NS) to the duration of time interval the CB units were kept in cryostorage condition. CONCLUSIONS: The data presented suggest that cryopreservation of CB units in a mechanical freezer at -150°C may represent an alternative cryostorage condition for CB cryopreservation.

Optimizing isolation culture and freezing methods to preserve Wharton's jelly's mesenchymal stem cell (MSC) properties: an MSC banking protocol validation for the Hellenic Cord Blood Bank.

BACKGROUND: Mesenchymal stem or stromal cells (MSCs) are a heterogeneous population that can be isolated from many tissues including umbilical cord Wharton's jelly (UC-WJ). Although initially limited in studies such as a hematopoietic stem cell transplantation adjuvant, an increasing number of clinical trials consider MSCs as a potential anti-inflammatory or a regenerative medicine agent. It has been proposed that creating a repository of MSCs would increase their availability for clinical applications. The aim of this study was to assess the optimal isolation and cryopreservation procedures to facilitate WJ MSC banking. STUDY DESIGN AND METHODS: Cells were isolated from UC-WJ using enzymatic digestion or plastic adhesion methods. Their isolation efficacy, growth kinetics, immunophenotype, and differentiation potential were studied, as well as the effects of freezing. Flow cytometry for common MSC markers was performed on all cases and differentiation was shown with histocytochemical staining. Finally, the isolation efficacy on cryopreserved WJ tissue fragments was tested. RESULTS: MSC isolation was successful using both isolation methods on fresh UC-WJ tissue. However, UC-WJ MSC isolation from frozen tissue fragments was impossible. Flow cytometry analysis revealed that only MSC markers were expressed on the surface of the isolated cells while differentiation assays showed that they were capable of trilinear differentiation. All the above characteristics were also preserved in isolated UC-WJ MSCs over the cryopreservation study period. CONCLUSION: These data showed that viable MSCs can only be isolated from fresh UC-WJ tissue, setting the foundation for clinical-grade banking.

Perspectives for the Use of Umbilical Cord Blood in Transplantation and Beyond: Initiatives for an Advanced and Sustainable Public Banking Program in Greece.

The umbilical cord blood (UCB) donated in public UCB banks is a source of hematopoietic stem cells (HSC) alternative to bone marrow for allogeneic HSC transplantation (HSCT). However, the high rejection rate of the donated units due to the strict acceptance criteria and the wide application of the haploidentical HSCT have resulted in significant limitation of the use of UCB and difficulties in the economic sustainability of the public UCB banks. There is an ongoing effort within the UCB community to optimize the use of UCB in the field of HSCT and a parallel interest in exploring the use of UCB for applications beyond HSCT i.e., in the fields of cell therapy, regenerative medicine and specialized transfusion medicine. In this report, we describe the mode of operation of the three public UCB banks in Greece as an example of an orchestrated effort to develop a viable UCB banking system by (a) prioritizing the enrichment of the national inventory by high-quality UCB units from populations with rare human leukocyte antigens (HLA), and (b) deploying novel sustainable applications of UCB beyond HSCT, through national and international collaborations. The Greek paradigm of the public UCB network may become an example for countries, particularly with high HLA heterogeneity, with public UCB banks facing sustainability difficulties and adds value to the international efforts aiming to sustainably expand the public UCB banking system.

Treatment with Umbilical Cord Blood Platelet Lysate Gel Improves Healing of Diabetic Foot Ulcer.

BACKGROUND: This study was conducted to examine the hypothesis that umbilical cord blood platelet lysate (UCB-PL) gel has a significant impact on the healing rate of DFU. Μethods: In this open-labeled, randomized controlled trial, 110 patients were randomized to treatment with UCB-PL gel (UCB-PL group, n = 52) every three days for one month or dressing with normal saline (control group, n = 58). All participants were followed up for 20 weeks post treatment. Ulcer surface area was assessed with the imitoMeasure application at two, four, and six weeks, and two, four and six months. This study's main outcome was the reduction in ulcer size over the six-month study period. RESULTS: The mean ulcer area at baseline was 4.1 cm2 in the UCB-PL group and 1.7 cm2 in the control group. At six months post treatment, patients on the UCB-PL treatment displayed a significant reduction in ulcer size compared to baseline 0.12 (0-8.16) in contrast to a more modest change in the control group 1.05 (0-24.7). The ulcer area was decreased at the end of the study in 40 patients (97.6%) in the UCB-PL group and 27 (73%) in the control group (Fisher's p = 0.002). CONCLUSIONS: The application of UCB-PL gel in DFU resulted in a significant reduction in ulcer size compared to regular saline dressing.

Autologous transplantation of adipose-derived stem cells enhances skin graft survival and wound healing in diabetic rats.

BACKGROUND: Diabetes can lead to impaired wound healing and skin grafts used surgically for diabetic wounds are often complicated with necrosis, although different therapies have been proposed. Adipose-derived stem cells (ASCs) participate in tissue repair processes and may have a role during impaired wound healing. In this study, autologous transplantation of ASCs was used to determine if it increases angiogenesis and skin graft survival and enhances wound healing in diabetic rats. METHODS: Adipose-derived stem cells were successfully isolated and cultured. A full-thickness skin graft model was used to determine the effects of locally administered ASCs in 10 rats rendered diabetic (group 1), whereas 10 others served as controls (group 2). Histological examination of skin grafts followed after 1 week. Additionally, immunohistochemical staining intensity of vascular endothelial growth factor (VEGF) and transforming growth factor ß3 (TGF-ß3) was assessed in all grafts. RESULTS: The gross and histological results showed significantly increased survival, angiogenesis, and epithelialization. Mean area of graft necrosis was significantly less in group 1 than in group 2 (7.49% vs 39.67%, P < 0.001). Statistically significant increase of capillary density, collagen intensity, VEGF, and TGF-ß3 expression was noted in group 1 compared with group 2. CONCLUSIONS: These findings suggest that autologous ASC transplantation can enhance skin graft survival in diabetic rats through differentiation, vasculogenesis, and secretion of growth factors such as VEGF and TGF-ß3. This might represent a novel therapeutic approach in skin graft surgery for diabetic wounds.

Clinical Benefit of Autologous Platelet-Rich Plasma Infusion in Ovarian Function Rejuvenation: Evidence from a Before-After Prospective Pilot Study.

Background: The intraovarian administration of autologous platelet-rich plasma (PRP) acts beneficially for the stimulation of follicle production in women presenting different forms of ovarian dysfunction. This pilot study aimed to evaluate and provide significant data regarding the efficacy of PRP to rejuvenate the ovaries. Methods: A total of 253 women aged 22-56 years, were divided into five groups, based on their status. All participants signed for informed consent for the current study. Blood sampling, preparation of PRP and intraovarian infusion of the latter were performed on all participants. The evaluation of PRP efficacy, a two-month follow-up detecting the levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol (E2) and anti-mullerian hormone (AMH), was performed for all participants. For women with advanced ages (>48 years), the restoration and regularity of the menstrual cycle were additionally evaluated. Results: After the two-month follow-up, the majority of the participants presented improvement in their hormonal profiles. Additionally, 17% of the women in this pilot study successfully conceived. The restoration of the menstrual cycle was detected in 15% of the women with advanced ages. Conclusions: Intraovarian infusion of autologous PRP exhibited remarkable evidence and promising results to restore ovarian insufficiency.

Efficient Decellularization of the Full-Thickness Rat-Derived Abdominal Wall to Produce Acellular Biologic Scaffolds for Tissue Reconstruction: Promising Evidence Acquired from In Vitro Results.

BACKGROUND: Functional restoration of abdominal wall defects represents one of the fundamental challenges of reconstructive surgery. Synthetic grafts or crosslinked animal-derived biological grafts are characterized by significant adverse reactions, which are mostly observed after their implantation. The aim of this study was to evaluate the efficacy of the decellularization protocol to produce a completely acellular full-thickness abdominal wall scaffold. METHODS: Full-thickness abdominal wall samples were harvested from Wistar rats and submitted to a three-cycle decellularization process. Histological, biochemical, and DNA quantification analyses were applied to evaluate the effect of the decellularization protocol. Mechanical testing and immunogenicity assessment were also performed. RESULTS: Histological, biochemical, and DNA analysis results showed efficient decellularization of the abdominal wall samples after the third cycle. Decellularized abdominal wall scaffolds were characterized by good biochemical and mechanical properties. CONCLUSION: The data presented herein confirm the effective production of a rat-derived full-thickness abdominal wall scaffold. Expanding this approach will allow the exploitation of the capacity of the proposed decellularization protocol in producing acellular abdominal wall scaffolds from larger animal models or human cadaveric donors. In this way, the utility of biological scaffolds with preserved in vivo remodeling properties may be one step closer to its application in clinical studies.

Multi-component cord blood banking: a proof-of-concept international exercise.

BACKGROUND: Most public cord blood (CB) banks currently discard more than 80% of umbilical CB units not suitable for hemopoietic stem cell transplant due to low stem cell count. Although CB platelets, plasma, and red blood cells have been used for experimental allogeneic applications in wound healing, corneal ulcer treatment, and neonatal transfusion, no standard procedures for their preparation have been defined internationally. MATERIALS AND METHODS: A network of 12 public CB banks in Spain, Italy, Greece, the UK, and Singapore developed a protocol to validate a procedure for the routine production of CB platelet concentrate (CB-PC), CB platelet-poor plasma (CB-PPP), and CB leukoreduced red blood cells (CB-LR-RBC) using locally available equipment and the commercial BioNest ABC and EF medical devices. CB units with >50 mL volume (excluding anticoagulant) and ≥150×109/L platelets were double centrifuged to obtain CB-PC, CB-PPP, and CB-RBC. The CB-RBC were diluted with saline-adenine-glucose-mannitol (SAGM), leukoreduced by filtration, stored at 2-6°C, and tested for hemolysis and potassium (K+) release over 15 days, with gamma irradiation performed on day 14. A set of acceptance criteria was pre-defined. This was for CB-PC: volume ≥5 mL and platelet count 800-1,200×109/L; for CB-PPP: platelet count <50×109/L; and for CB-LR-RBC: volume ≥20 mL, hematocrit 55-65%, residual leukocytes <0.2×106/unit, and hemolysis ≤0.8%. RESULTS: Eight CB banks completed the validation exercise. Compliance with acceptance criteria was 99% for minimum volume and 86.1% for platelet count in CB-PC, and 90% for platelet count in CB-PPP. Compliance in CB-LR-RBC was 85.7% for minimum volume, 98.9% for residual leukocytes, and 90% for hematocrit. Compliance for hemolysis ≤0.8% decreased from 89.0 to 63.2% from day 0 to 15. K+ release increased from 3.0±1.8 to 25.0±7.0 mmol/L from day 0 to 15, respectively. DISCUSSION: The MultiCord12 protocol was a useful tool to develop preliminary standardization of CB-PC, CB-PPP, and CB-LR-RBC.

Mesenchymal stromal cell delivery as a potential therapeutic strategy against COVID-19: Promising evidence from in vitro results.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the coronavirus disease 2019 (COVID-19) pandemic, which was initiated in December 2019. COVID-19 is characterized by a low mortality rate (< 6%); however, this percentage is higher in elderly people and patients with underlying disorders. COVID-19 is characterized by mild to severe outcomes. Currently, several therapeutic strategies are evaluated, such as the use of anti-viral drugs, prophylactic treatment, monoclonal antibodies, and vaccination. Advanced cellular therapies are also investigated, thus representing an additional therapeutic tool for clinicians. Mesenchymal stromal cells (MSCs), which are known for their immunoregulatory properties, may halt the induced cytokine release syndrome mediated by SARS-CoV-2, and can be considered as a potential stem cell therapy. AIM: To evaluate the immunoregulatory properties of MSCs, upon stimulation with COVID-19 patient serum. METHODS: MSCs derived from the human Wharton's Jelly (WJ) tissue and bone marrow (BM) were isolated, cryopreserved, expanded, and defined according to the criteria outlined by the International Society for Cellular Therapies. Then, WJ and BM-MSCs were stimulated with a culture medium containing 15% COVID-19 patient serum, 1% penicillin-streptomycin, and 1% L-glutamine for 48 h. The quantification of interleukin (IL)-1 receptor a (Ra), IL-6, IL-10, IL-13, transforming growth factor (TGF)-ß1, vascular endothelial growth factor (VEGF)-a, fibroblast growth factor (FGF), platelet-derived growth factor (PDGF), and indoleamine-2,3-dioxygenase (IDO) was performed using commercial ELISA kits. The expression of HLA-G1, G5, and G7 was evaluated in unstimulated and stimulated WJ and BM-MSCs. Finally, the interactions between MSCs and patients' macrophages were established using co-culture experiments. RESULTS: Thawed WJ and BM-MSCs exhibited a spindle-shaped morphology, successfully differentiated to "osteocytes", "adipocytes", and "chondrocytes", and in flow cytometric analysis were characterized by positivity for CD73, CD90, and CD105 (> 95%) and negativity for CD34, CD45, and HLA-DR (< 2%). Moreover, stimulated WJ and BM-MSCs were characterized by increased cytoplasmic granulation, in comparison to unstimulated cells. The HLA-G isoforms (G1, G5, and G7) were successfully expressed by the unstimulated and stimulated WJ-MSCs. On the other hand, only weak expression of HLA-G1 was identified in BM-MSCs. Stimulated MSCs secreted high levels of IL-1Ra, IL-6, IL-10, IL-13, TGF-ß1, FGF, VEGF, PDGF, and IDO in comparison to unstimulated cells (P < 0.05) after 12 and 24 h. Finally, macrophages derived from COVID-19 patients successfully adapted the M2 phenotype after co-culturing with stimulated WJ and BM-MSCs. CONCLUSION: WJ and BM-MSCs successfully produced high levels of immunoregulatory agents, which may efficiently modulate the over-activated immune responses of critically ill COVID-19 patients.

Modern Approaches in Cardiovascular Disease Therapeutics: From Molecular Genetics to Tissue Engineering.

Cardiovascular disease (CVD) currently represents one of the leading causes of death worldwide. It is estimated that more than 17.9 million people die each year due to CVD manifestations. Often, occlusion or stenosis of the vascular network occurs, either in large- or small-diameter blood vessels. Moreover, the obstruction of small vessels such as the coronary arteries may be related to more pronounced events, which can be life-threatening. The gold standard procedure utilizes the transplantation of secondary vessels or the use of synthetic vascular grafts. However, significant adverse reactions have accompanied the use of the above grafts. Therefore, modern therapeutic strategies must be evaluated for better disease administration. In the context of alternative therapies, advanced tissue-engineering approaches including the decellularization procedure and the 3D additive bioprinting methods, have been proposed. In this way the availability of bioengineered vascular grafts will be increased, covering the great demand that exists globally. In this Special Issue of Bioengineering, we tried to highlight the modern approaches which are focused on CVD therapeutics. This issue includes articles related to the efficient development of vascular grafts, 3D printing approaches and suitable atherosclerosis models.

Improved Repopulation Efficacy of Decellularized Small Diameter Vascular Grafts Utilizing the Cord Blood Platelet Lysate.

BACKGROUND: The development of functional bioengineered small-diameter vascular grafts (SDVGs), represents a major challenge of tissue engineering. This study aimed to evaluate the repopulation efficacy of biological vessels, utilizing the cord blood platelet lysate (CBPL). METHODS: Human umbilical arteries (hUAs, n = 10) were submitted to decellularization. Then, an evaluation of decellularized hUAs, involving histological, biochemical and biomechanical analysis, was performed. Wharton's Jelly (WJ) Mesenchymal Stromal Cells (MSCs) were isolated and characterized for their properties. Then, WJ-MSCs (1.5 × 106 cells) were seeded on decellularized hUAs (n = 5) and cultivated with (Group A) or without the presence of the CBPL, (Group B) for 30 days. Histological analysis involving immunohistochemistry (against Ki67, for determination of cell proliferation) and indirect immunofluorescence (against activated MAP kinase, additional marker for cell growth and proliferation) was performed. RESULTS: The decellularized hUAs retained their initial vessel's properties, in terms of key-specific proteins, the biochemical and biomechanical characteristics were preserved. The evaluation of the repopulation process indicated a more uniform distribution of WJ-MSCs in group A compared to group B. The repopulated vascular grafts of group B were characterized by greater Ki67 and MAP kinase expression compared to group A. CONCLUSION: The results of this study indicated that the CBPL may improve the repopulation efficacy, thus bringing the biological SDVGs one step closer to clinical application.

Optimizing Decellularization Strategies for the Efficient Production of Whole Rat Kidney Scaffolds.

BACKGROUND: Renal dysfunction remains a global issue, with chronic kidney disease being the 18th most leading cause of death, worldwide. The increased demands in kidney transplants, led the scientific society to seek alternative strategies, utilizing mostly the tissue engineering approaches. Unlike to perfusion decellularization of kidneys, we proposed alternative decellularization strategies to obtain acellular kidney scaffolds. The aim of this study was the evaluation of two different decellularization approaches for producing kidney bioscaffolds. METHODS: Rat kidneys from Wistar rats, were submitted to decellularization, followed two different strategies. The decellularization solutions used in both approaches were the same and involved the use of 3-[(3-cholamidopropyl) dimethylammonio]-1-propanesulfonate and sodium dodecyl sulfate buffers for 12 h each, followed by incubation in a serum medium. Both approaches involved 3 decellularization cycles. Histological analysis, biochemical and DNA quantification were performed. Cytotoxicity assay and repopulation of acellular kidneys were also applied. RESULTS: Histological, biochemical and DNA quantification confirmed that the 2nd approach had the best outcome regarding the kidney composition and cell elimination. Acellular kidneys from both approaches were successfully recellularized. CONCLUSION: Based on the above data, the production of kidney scaffolds with the proposed cost- effective decellularization approaches, was efficient.

Variation in health plan coverage of ESAs for anemia due to chronic kidney disease.

BACKGROUND: Because health plans each issue their own policies, drug coverage can vary. This variation can result in patients having unequal access to treatment. In this study, we evaluate commercial health plans' coverage policies for erythropoiesis-stimulating agents (ESAs) for patients with anemia resulting from chronic kidney disease (CKD). OBJECTIVES: To assess how a set of US commercial health plans cover ESAs for patients with anemia due to CKD. Our second objective was to examine the evidence that the plans reviewed when formulating their coverage policies. METHODS: We used the Tufts Medical Center Specialty Drug and Evidence and Coverage Database to identify coverage policies issued by 17 of the largest US commercial health plans for ESAs. The following drugs were indicated for anemia due to CKD: darbepoetin alfa, methoxy polyethylene glycol-epoetin beta, epoetin alfa (available as two brands), and epoetin alfa-epbx. Coverage policies were current as of May 2019. We determined whether the health plans applied any restrictions, such as step therapy protocols or patient subgroup restrictions, in their coverage policies. We categorized the evidence that plans cited to support their policies into seven categories: randomized controlled trials (RCTs), real-world evidence (RWE) studies (studies based on data collected in a real-world setting), other clinical studies (eg, single arm trials), systematic reviews and/or meta-analyses, clinical or treatment guidelines, health technology assessments, and economic evaluations. RESULTS: We categorized 72.5% of coverage policies (58/80 policies) as equivalent to the FDA label and 27.5% (22/80 policies) as more restrictive. In restricted policies, plans most often applied step therapy protocols (18/22 policies), followed by prescriber requirements (4/22 policies), and patient subgroup restrictions (3/22 policies). Five health plans applied restrictions in at least half of their coverage policies; seven plans did not apply restrictions in any policy. Plans that cited evidence reviewed an average of 10 citations across their ESA coverage policies, ranging from one to 29 studies. Plans varied with respect to the types of cited studies: at least 50% of evidence cited by five health plans was RCTs, while half or more of the evidence cited by four health plans was clinical or treatment guidelines. CONCLUSIONS: Health plans varied in how they covered ESAs for patients with anemia due to CKD and in the evidence cited in their coverage policies. Inconsistencies in plans' coverage policies may have implications for patients' access to ESAs. DISCLOSURES: This study was funded by Otsuka Pharmaceutical Development and Commercialization. Sanon, Redmond, and Mogahadam are employed by Otsuka Pharmaceutical. Michalopoulos was employed by Otsuka Pharmaceutical at the time of this study. Margaretos, Panzer, and Chambers are employed by Tufts Medical Center, Institute for Clinical Research and Health Policy Studies, Center for the Evaluation of Value and Risk in Health. Lai was with Tufts Medical Center, Institute for Clinical Research and Health Policy Studies, Center for the Evaluation of Value and Risk in Health at the time of this study.