IL-8 enhances the angiogenic potential of human bone marrow mesenchymal stem cells by increasing vascular endothelial growth factor

Protective effects of autologous bone marrow-derived mesenchymal stem cell transplantation on acute radioactive enteritis in Beagle dogs

BACKGROUND

Radiation enteritis is a common complication of radiation therapy in which the surrounding normal intestinal tissue is damaged by ionising radiation, and there is no standard pharmacological prophylaxis or treatment regimen available. Mesenchymal stem cell transplantation can be used for radiation protection and the treatment of acute radiation injury, but its therapeutic mechanism of action remains unclear.

AIM

To investigate the protective effects of autologous bone marrow-derived mesenchymal stem cell (ABMSC) transplantation on radiation-induced intestinal injury.

METHODS

A model of acute radioactive enteritis was established in dogs by applying abdominal intensity-modulated radiation at a single X-ray dose of 12 Gy. ABMSCs were transplanted into the mesenteric artery with the technology of femoral artery puncture and DSA imaging two days after radiation. Visual and histopathological changes of the experimental dogs were observed. Different kinds of cytokines from intestinal samples were tested using Quantibody Canine Cytokine Array method. Enzyme-linked immunosorbent assay (ELISA) was also used to evaluate the cytokines changes in serum.

RESULTS

The ABMSCs group showed significant improvements in survival status compared with the blank and saline treatment groups. Histological observations revealed that the former had lower histological scores than the later after treatment (P < 0.05). Compared to the control groups, interleukin (IL)-10 and monocyte chemotactic protein (MCP)-1 from intestinal samples showed a remarkable increase and ELISA of serum samples proved higher secretion of the two target cytokines in the ABMSCs group (P < 0.05).

CONCLUSION

Our data suggest that transplantation of ABMSCs promotes intestinal recovery after acute radioactive injury in Beagle dogs. The cytokines of IL-10 and MCP-1 might play an important role in this process.

Volumetric bioprinting of the osteoid niche

Volumetric bioprinting has revolutionized the field of biofabrication by enabling the creation of cubic centimeter-scale living constructs at faster printing times (in the order of seconds). However, a key challenge remains: developing a wider variety of available osteogenic bioinks that allow osteogenic maturation of the encapsulated cells within the construct. Herein, the bioink exploiting a step-growth mechanism (norbornene-norbornene functionalized gelatin in combination with thiolated gelatin-GelNBNBSH) outperformed the bioink exploiting a chain-growth mechanism (gelatin methacryloyl-GelMA), as the necessary photo-initiator concentration was three times lower combined with a more than 50% reduction in required light exposure dose resulting in an improved positive and negative resolution. To mimic the substrate elasticity of the osteoid, two concentrations of the photo-initiator Li-TPO-L (1 and 10 mg ml-1) were compared for post-curing whereby the lowest concentration was selected since it resulted in attaining the osteogenic substrate elasticity combined with excellent biocompatibility with HT1080 cells (>95%). Further physico-chemical testing revealed that the volumetric printing (VP) process affected the degradation time of the constructs with volumetric constructs degrading slower than the control sheets which could be due to the introduced fibrillar structure inherent to the VP process. Moreover, GelNBNBSH volumetric constructs significantly outperformed the GelMA volumetric constructs in terms of a 2-fold increase in photo-crosslinkable moiety conversion and a 3-fold increase in bulk stiffness of the construct. Finally, a 21-day osteogenic cell study was performed with highly viable dental pulp-derived stem cells (>95%) encapsulated within the volumetric printed constructs. Osteogenesis was greatly favored for the GelNBNBSH constructs through enhanced early (alkaline phosphatase activity) and late maturation (calcium production) osteogenic markers. After 21 d, a secretome analysis revealed a more mature osteogenic phenotype within GelNBNBSH constructs as compared to their chain-growth counterpart in terms of osteogenic, immunological and angiogenic signaling.

Exploring mesenchymal stem cells homing mechanisms and improvement strategies

Mesenchymal stem cells (MSCs) are multipotent cells with high self-renewal and multilineage differentiation abilities, playing an important role in tissue healing. Recent advancements in stem cell-based technologies have offered new and promising therapeutic options in regenerative medicine. Upon tissue damage, MSCs are immediately mobilized from the bone marrow and move to the injury site via blood circulation. Notably, allogenically transplanted MSCs can also home to the damaged tissue site. Therefore, MSCs hold great therapeutic potential for curing various diseases. However, one major obstacle to this approach is attracting MSCs specifically to the injury site following systemic administration. In this review, we describe the molecular pathways governing the homing mechanism of MSCs and various strategies for improving this process, including targeted stem cell administration, target tissue modification, in vitro priming, cell surface engineering, genetic modifications, and magnetic guidance. These strategies are crucial for directing MSCs precisely to the injury site and, consequently, enhancing their migration and local tissue repair properties. Specifically, our review provides a guide to improving the therapeutic efficacy of clinical applications of MSCs through optimized in vivo administration and homing capacities.

Decoding secret role of mesenchymal stem cells in regulating cancer stem cells and drug resistance

Drug resistance caused by the efflux of chemotherapeutic drugs is one of the most challenging obstacles to successful cancer therapy. Several efflux transporters have been identified since the discovery of the P-gp/ABCB1 transporter in 1976. Over the last four decades, researchers have focused on developing efflux transporter inhibitors to overcome drug resistance. However, even with the third-generation inhibitors available, we are still far from effectively inhibiting the efflux transporters. Additionally, Cancer stem cells (CSCs) pose another significant challenge, contributing to cancer recurrence even after successful treatment. The ability of CSCs to enter dormancy and evade detection makes them almost invulnerable to chemotherapeutic drug treatment. In this review, we discuss how Mesenchymal stem cells (MSCs), one of the key components of the Tumor Microenvironment (TME), regulate both the CSCs and efflux transporters. We propose a new approach focusing on MSCs, which can be crucial to successfully address CSCs and efflux transporters.

Pharmacokinetic characteristics of mesenchymal stem cells in translational challenges

Over the past two decades, mesenchymal stem/stromal cell (MSC) therapy has made substantial strides, transitioning from experimental clinical applications to commercial products. MSC therapies hold considerable promise for treating refractory and critical conditions such as acute graft-versus-host disease, amyotrophic lateral sclerosis, and acute respiratory distress syndrome. Despite recent successes in clinical and commercial applications, MSC therapy still faces challenges when used as a commercial product. Current detection methods have limitations, leaving the dynamic biodistribution, persistence in injured tissues, and ultimate fate of MSCs in patients unclear. Clarifying the relationship between the pharmacokinetic characteristics of MSCs and their therapeutic effects is crucial for patient stratification and the formulation of precise therapeutic regimens. Moreover, the development of advanced imaging and tracking technologies is essential to address these clinical challenges. This review provides a comprehensive analysis of the kinetic properties, key regulatory molecules, different fates, and detection methods relevant to MSCs and discusses concerns in evaluating MSC druggability from the perspective of integrating pharmacokinetics and efficacy. A better understanding of these challenges could improve MSC clinical efficacy and speed up the introduction of MSC therapy products to the market.

LINE-1 RNA triggers matrix formation in bone cells via a PKR-mediated inflammatory response

Transposable elements (TEs) are mobile genetic modules of viral derivation that have been co-opted to become modulators of mammalian gene expression. TEs are a major source of endogenous dsRNAs, signaling molecules able to coordinate inflammatory responses in various physiological processes. Here, we provide evidence for a positive involvement of TEs in inflammation-driven bone repair and mineralization. In newly fractured mice bone, we observed an early transient upregulation of repeats occurring concurrently with the initiation of the inflammatory stage. In human bone biopsies, analysis revealed a significant correlation between repeats expression, mechanical stress and bone mineral density. We investigated a potential link between LINE-1 (L1) expression and bone mineralization by delivering a synthetic L1 RNA to osteoporotic patient-derived mesenchymal stem cells and observed a dsRNA-triggered protein kinase (PKR)-mediated stress response that led to strongly increased mineralization. This response was associated with a strong and transient inflammation, accompanied by a global translation attenuation induced by eIF2α phosphorylation. We demonstrated that L1 transfection reshaped the secretory profile of osteoblasts, triggering a paracrine activity that stimulated the mineralization of recipient cells.

Deciphering the divergent transcriptomic landscapes of cervical cancer cells grown in 3D and 2D cell culture systems

Cervical cancer remains a significant health challenge for women worldwide, with a disproportionate impact on developing regions like sub-Saharan Africa. Taking advantage of recent advancements in developing suitable preclinical models to study cell proliferation, differentiation, and gene expression, we used RNA sequencing to compare the transcriptomic profiles of SiHa cervical cancer cells grown in 3D versus 2D culture systems. Pathway analysis of 3D cultures revealed upregulation of immune activation, angiogenesis, and tissue remodeling pathways. The high expression of cytokines, chemokines, matrix metalloproteinases, and immediate early genes, suggests that 3D cultures replicate the tumor microenvironment better than 2D monolayer cultures. HPV gene expression analysis further demonstrated higher expression levels of HPV16 E1, E2, E6, and E7 genes in 3D versus 2D cultures. Further, by using a set of linear models, we identified 79 significantly differentially expressed genes in 3D culture compared to 2D culture conditions, independent of HPV16 viral gene effects. We subsequently validated five of these genes at the protein level in both the SiHa cell line and a newly developed, patient-derived cervical cancer cell line. In addition, correlation analysis identified 26 human genes positively correlated with viral genes across 2D and 3D culture conditions. The top five 3D versus 2D differentially expressed and HPV-correlated genes were validated via qRT-PCR in our patient derived cell line. Altogether, these findings suggest that 3D cultures provide superior model systems to explore mechanisms of immune evasion, cancer progression and antiviral therapeutics.

Vasa vasorum: The role in intracranial physiology and pathophysiology

Background

Vasa vasorum (VVs) is a Latin word representing vessels of vessels. VVs are usually found on the adventitia of the parent vessel and infrequently reach the media and intima, depending on the size and type of the parent vessels and physiological and pathological conditions. The VVs include arteries, capillaries, veins, and lymphatic vessels, involving the oxygenation and nourishment of the vessel's wall to sustain its healthy state. Accumulated studies have revealed that VVs are involved in various intracranial lesions, including atherosclerotic diseases, aneurysms, and shunt diseases. The current review aims to review and integrate past and recent findings and knowledge on VVs and to facilitate our understanding of VVs and intracranial pathology involving VVs.

Methods

A literature review was carried out with a focus on the role of VVs by searching the Pubmed database.

Results

We identified 71 articles that discuss the role of VVs. We discussed the anatomical structure, physiological significance, and pathological significance of the VV.

Conclusion

VV is not only involved in the nutrition and metabolism of the vascular wall but is also deeply involved in the pathogenesis of inflammation, ischemia, and thrombosis of the vascular wall. In addition, in the central nervous system, intracranial vascular wall nutrient particularities and VVs are closely related to the pathogenesis of cerebral aneurysms, subarachnoid hemorrhage, arteriovenous shunt disease, atherosclerotic lesions, and other conditions.

Mesenchymal stromal cells and CAR-T cells in regenerative medicine: The homing procedure and their effective parameters

Mesenchymal stromal cells (MSCs) and chimeric antigen receptor (CAR)-T cells are two core elements in cell therapy procedures. MSCs have significant immunomodulatory effects that alleviate inflammation in the tissue regeneration process, while administration of specific chemokines and adhesive molecules would primarily facilitate CAR-T cell trafficking into solid tumors. Multiple parameters affect cell homing, including the recipient's age, the number of cell passages, proper cell culture, and the delivery method. In addition, several chemokines are involved in the tumor microenvironment, affecting the homing procedure. This review discusses parameters that improve the efficiency of cell homing and significant cell therapy challenges. Emerging comprehensive mechanistic strategies such as non-systemic and systemic homing that revealed a significant role in cell therapy remodeling were also reviewed. Finally, the primary implications for the development of combination therapies that incorporate both MSCs and CAR-T cells for cancer treatment were discussed.

Specifics of Cryopreservation of Hydrogel Biopolymer Scaffolds with Encapsulated Mesenchymal Stem Cells

The demand for regenerative medicine products is growing rapidly in clinical practice. Unfortunately, their use has certain limitations. One of these, which significantly constrains the widespread distribution and commercialization of such materials, is their short life span. For products containing suspensions of cells, this issue can be solved by using cryopreservation. However, this approach is rarely used for multicomponent tissue-engineered products due to the complexity of selecting appropriate cryopreservation protocols and the lack of established criteria for assessing the quality of such products once defrosted. Our research is aimed at developing a cryopreservation protocol for an original hydrogel scaffold with encapsulated MSCs and developing a set of criteria for assessing the quality of their functional activity in vitro. The scaffolds were frozen using two alternative types of cryocontainers and stored at either -40 °C or -80 °C. After cryopreservation, the external state of the scaffolds was evaluated in addition to recording the cell viability, visible changes during subsequent cultivation, and any alterations in proliferative and secretory activity. These observations were compared to those of scaffolds cultivated without cryopreservation. It was shown that cryopreservation at -80 °C in an appropriate type of cryocontainer was optimal for the hydrogels/adipose-derived stem cells (ASCs) tested if it provided a smooth temperature decrease during freezing over a period of at least three hours until the target values of the cryopreservation temperature regimen were reached. It was shown that evaluating a set of indicators, including the viability, the morphology, and the proliferative and secretory activity of the cells, enables the characterization of the quality of a tissue-engineered construct after its withdrawal from cryopreservation, as well as indicating the effectiveness of the cryopreservation protocol.

A Synergic Strategy: Adipose-Derived Stem Cell Spheroids Seeded on 3D-Printed PLA/CHA Scaffolds Implanted in a Bone Critical-Size Defect Model

Bone critical-size defects and non-union fractures have no intrinsic capacity for self-healing. In this context, the emergence of bone engineering has allowed the development of functional alternatives. The aim of this study was to evaluate the capacity of ASC spheroids in bone regeneration using a synergic strategy with 3D-printed scaffolds made from poly (lactic acid) (PLA) and nanostructured hydroxyapatite doped with carbonate ions (CHA) in a rat model of cranial critical-size defect. In summary, a set of results suggests that ASC spheroidal constructs promoted bone regeneration. In vitro results showed that ASC spheroids were able to spread and interact with the 3D-printed scaffold, synthesizing crucial growth factors and cytokines for bone regeneration, such as VEGF. Histological results after 3 and 6 months of implantation showed the formation of new bone tissue in the PLA/CHA scaffolds that were seeded with ASC spheroids. In conclusion, the presence of ASC spheroids in the PLA/CHA 3D-printed scaffolds seems to successfully promote bone formation, which can be crucial for a significant clinical improvement in critical bone defect regeneration.

Successful fat-only whole breast reconstruction using cultured mature adipocytes and conditioned medium containing MCP-1

A mastectomy is a curative treatment for breast cancer. It causes breast and soft tissue deficits, resulting in a chest with poor vascularity. Autologous tissue breast reconstruction is commonly associated with donor site morbidity. Breast implants are another reconstruction alternative, but they are associated with infection, rupture, and the need for replacement. Autologous aspirated fat grafting has appeared as an ideal breast reconstruction method, but low graft viability and high resorption remain as the main shortcomings. We developed a novel method for fat-only grafts using cultured mature adipocytes (CMAs) mixed with their condition medium. Twenty-five mastectomy patients, aged 32-72 years, received a mixed grafting of CMAs, MCP1-containing condition medium, and fat grafts for total breast reconstruction. In follow-up periods of 24-75 months, MRI analysis showed full thickness fat-engraftment. The cell proliferation marker Ki67 was negative in post-transplant biopsy specimens from all patients. Aesthetic full breast morphology was achieved, patient satisfaction was evaluated 1 year and 3-6 years after surgery. All grafts were confirmed safe, demonstrating high reliability and long-term sustainability.

Comparative Analysis of Somatic Stem Cells With Emphasis on Osteochondral Tissue Regeneration

Congenital anomalies, diseases, and injuries may result in osteochondral damage. Recently, a big hope has been given to somatic stem cells (SSCs) which are characterized as undifferentiated cells with an ability of long-term self-renewing and plasticity. They are adherent with a fibroblast-like morphology in vitro and express various surface markers (e.g. CD29, CD73, CD90, and CD105), but they are negative for CD31, CD34, CD45, and HLA-DR. SSCs secrete various bioactive molecules, which are involved in processes of regeneration. The main goal of the present study was the characterization and comparison of biological properties of SSCs obtained from adipose tissue, dental pulp, and urine concerning osteochondral regeneration. SSCs were maintained in an appropriate growth medium up to the third passage and were analyzed by light and electron microscope. The immunophenotype was analyzed by flow cytometry. The kinetics of proliferation was measured by MTT assay. Human Cytokine/Chemokine Multiplex Assay was used, and SSCs secretory profile was measured by Luminex MAGPIX® Instrument. Pellet cultures and a chondrogenic medium were used to induce chondrogenic differentiation. Osteogenic differentiation was induced by the osteogenic medium. Chondrogenic and osteogenic differentiation was analyzed by real-time PCR. SSCs had similar fibroblast-like morphology. They have similar kinetics of proliferation. SSCs shared the expression CD29, CD44, CD73, CD90, and CD105. They lack expression of CD29 and CD34. SSCs secerned similar levels of IL10 and IL18 while differing in IFN-gamma, IL6, IL8, MCP-1, and RANTES production. SSCs possess a similar capacity for chondrogenic differentiation but slightly differ in osteogenic differentiation. In conclusion, it can be emphasized that SSCs from adipose tissue, dental pulp, and urine share the majority of cellular characteristics typical for SSCs and have great potential to be used in osteochondral tissue regeneration.

Restoration of spinal cord injury: From endogenous repairing process to cellular therapy

Spinal cord injury (SCI) disrupts neurological pathways and impacts sensory, motor, and autonomic nerve function. There is no effective treatment for SCI currently. Numerous endogenous cells, including astrocytes, macrophages/microglia, and oligodendrocyte, are involved in the histological healing process following SCI. By interfering with cells during the SCI repair process, some advancements in the therapy of SCI have been realized. Nevertheless, the endogenous cell types engaged in SCI repair and the current difficulties these cells confront in the therapy of SCI are poorly defined, and the mechanisms underlying them are little understood. In order to better understand SCI and create new therapeutic strategies and enhance the clinical translation of SCI repair, we have comprehensively listed the endogenous cells involved in SCI repair and summarized the six most common mechanisms involved in SCI repair, including limiting the inflammatory response, protecting the spared spinal cord, enhancing myelination, facilitating neovascularization, producing neurotrophic factors, and differentiating into neural/colloidal cell lines.

Immune Transcriptome and Secretome Differ between Human CD71+ Erythroid Cells from Adult Bone Marrow and Fetal Liver Parenchyma

CD71⁺ erythroid cells (CECs) were only known as erythrocyte progenitors not so long ago. In present times, however, they have been shown to be active players in immune regulation, especially in immunosuppression by the means of ROS, arginase-1 and arginase-2 production. Here, we uncover organ-of-origin differences in cytokine gene expression using NanoString and protein production using Bio-Plex between CECs from healthy human adult bone marrow and from human fetal liver parenchyma. Namely, healthy human adult bone marrow CECs both expressed and produced IFN-a, IL-1b, IL-8, IL-18 and MIF mRNA and protein, while human fetal liver parenchyma CECs expressed and produced IFN-a, IL15, IL18 and TNF-b mRNA and protein. We also detected TLR2 and TLR9 gene expression in both varieties of CECs and TLR1 and NOD2 gene expression in human fetal liver parenchyma CECs only. These observations suggest that there might be undiscovered roles in immune response for CECs.

Human umbilical cord-derived mesenchymal stem cells not only ameliorate blood glucose but also protect vascular endothelium from diabetic damage through a paracrine mechanism mediated by MAPK/ERK signaling

BACKGROUND

Endothelial damage is an initial step of macro- and micro-vasculature dysfunctions in diabetic patients, accounting for a high incidence of diabetic vascular complications, such as atherosclerosis, nephropathy, retinopathy, and neuropathy. However, clinic lacks effective therapeutics targeting diabetic vascular complications. In field of regenerative medicine, mesenchymal stem cells, such as human umbilical cord-derived MSCs (hucMSCs), have great potential in treating tissue damage.

METHODS

To determine whether hucMSCs infusion could repair diabetic vascular endothelial damage and how it works, this study conducted in vivo experiment on streptozotocin-induced diabetic rat model to test body weight, fasting blood glucose (FBG), serum ICAM-1 and VCAM-1 levels, histopathology and immunohistochemical staining of aorta segments. In vitro experiment was further conducted to determine the effects of hucMSCs on diabetic vascular endothelial damage, applying assays of resazurin staining, MTT cell viability, wound healing, transwell migration, and matrigel tube formation on human umbilical vein endothelial cells (HUVECs). RNA sequencing (RNAseq) and molecular experiment were conducted to clarify the mechanism of hucMSCs.

RESULTS

The in vivo data revealed that hucMSCs partially restore the alterations of body weight, FBG, serum ICAM-1 and VCAM-1 levels, histopathology of aorta and reversed the abnormal phosphorylation of ERK in diabetic rats. By using the conditioned medium of hucMSCs (MSC-CM), the in vitro data revealed that hucMSCs improved cell viability, wound healing, migration and angiogenesis of the high glucose-damaged HUVECs through a paracrine action mode, and the altered gene expressions of IL-6, TNF-α, ICAM-1, VCAM-1, BAX, P16, P53 and ET-1 were significantly restored by MSC-CM. RNAseq incorporated with real-time PCR and Western blot results clarified that high glucose activated MAPK/ERK signaling in HUVECs, while MSC-CM reversed the abnormal phosphorylation of ERK and overexpressions of MKNK2, ERBB3, MYC and DUSP5 in MAPK/ERK signaling pathway.

CONCLUSIONS

HucMSCs not only ameliorated blood glucose but also protected vascular endothelium from diabetic damage, in which MAPK/ERK signaling mediated its molecular mechanism of paracrine action. Our findings provided novel knowledge of hucMSCs in the treatment of diabetes and suggested a prospective strategy for the clinical treatment of diabetic vascular complications.

Potential mechanisms and therapeutic targets of mesenchymal stem cell transplantation for ischemic stroke

Ischemic stroke is one of the major causes of death and disability in the world. Currently, most patients cannot choose intravenous thrombolysis or intravascular mechanical thrombectomy because of narrow therapeutic windows and severe complications. Stem cell transplantation is an emerging treatment and has been studied in various central nervous system diseases. Animal and clinical studies showed that transplantation of mesenchymal stem cells (MSCs) could alleviate neurological deficits and bring hope for ischemic stroke treatment. This article reviewed biological characteristics, safety, feasibility and efficacy of MSCs therapy, potential therapeutic targets of MSCs, and production process of Good Manufacturing Practices-grade MSCs, to explore the potential therapeutic targets of MSCs in the process of production and use and provide new therapeutic directions for ischemic stroke.

Human Umbilical Cord Blood-Derived CD133+CD34+ Cells Protect Retinal Endothelial Cells and Ganglion Cells in X-Irradiated Rats through Angioprotective and Neurotrophic Factors

Radiation retinopathy (RR) is a common complication following radiation therapy of globe, head, and neck malignancies, and is characterized by microangiopathy, neuroretinopathy, and the irreversible loss of visual function. To date, there is no effective treatment for RR. Stem cells have been clinically used to treat retinal degeneration. CD133+CD34+ cells from human umbilical cord blood (hUCB-CD133+CD34+ cells), a subpopulation of hematopoietic stem cells, were applied to determine their protective efficacy on irradiated rat retinas. After X-ray irradiation on the retinas, rats were intravitreally injected with hUCB-CD133+CD34+ cells. Transplantation of hUCB-CD133+CD34+ cells prevented retinal dysfunction 2 weeks post-operation and lasted at least 8 weeks. CD133+CD34+ cells were distributed along the retinal vessel and migrated to the ganglion cell layer. Moreover, grafted CD133+CD34+ cells reduced the apoptosis of endothelial and ganglion cells in irradiated rats and increased the number of survived CD31+ retinal endothelial cells and Brn3a+ ganglion cells at 2 and 4 weeks, respectively, post-operation. Co-culturing of CD133+CD34+ cells or supernatants with irradiated human retinal microvascular endothelial cells (hRECs) in vitro, confirmed that CD133+CD34+ cells ameliorated hREC apoptosis caused by irradiation. Mechanistically, we found that angioprotective mediators and neurotrophic factors were secreted by CD133+CD34+ cells, which might attenuate irradiation-induced injury of retinal endothelial cells and ganglion cells. hUCB-CD133+CD34+ cell transplantation, as a novel treatment, protects retinal endothelial and ganglion cells of X-irradiated rat retinas, possibly through angioprotective and neurotrophic factors.

Mesenchymal Stem/Stromal Cells and Their Paracrine Activity-Immunomodulation Mechanisms and How to Influence the Therapeutic Potential

With high clinical interest to be applied in regenerative medicine, Mesenchymal Stem/Stromal Cells have been widely studied due to their multipotency, wide distribution, and relative ease of isolation and expansion in vitro. Their remarkable biological characteristics and high immunomodulatory influence have opened doors to the application of MSCs in many clinical settings. The therapeutic influence of these cells and the interaction with the immune system seems to occur both directly and through a paracrine route, with the production and secretion of soluble factors and extracellular vesicles. The complex mechanisms through which this influence takes place is not fully understood, but several functional manipulation techniques, such as cell engineering, priming, and preconditioning, have been developed. In this review, the knowledge about the immunoregulatory and immunomodulatory capacity of MSCs and their secretion products is revisited, with a special focus on the phenomena of migration and homing, direct cell action and paracrine activity. The techniques for homing improvement, cell modulation and conditioning prior to the application of paracrine factors were also explored. Finally, multiple assays where different approaches were applied with varying success were used as examples to justify their exploration.

Interleukins and Ischemic Stroke

Ischemic stroke after cerebral artery occlusion is one of the major causes of chronic disability worldwide. Interleukins (ILs) play a bidirectional role in ischemic stroke through information transmission, activation and regulation of immune cells, mediating the activation, multiplication and differentiation of T and B cells and in the inflammatory reaction. Crosstalk between different ILs in different immune cells also impact the outcome of ischemic stroke. This overview is aimed to roughly discuss the multiple roles of ILs after ischemic stroke. The roles of IL-1, IL-2, IL-4, IL-5, IL-6, IL-8, IL-9, IL-10, IL-12, IL-13, IL-15, IL-16, IL-17, IL-18, IL-19, IL-21, IL-22, IL-23, IL-32, IL-33, IL-34, IL-37, and IL-38 in ischemic stroke were discussed in this review.

A Molecular Analysis of Cytokine Content across Extracellular Vesicles, Secretions, and Intracellular Space from Different Site-Specific Adipose-Derived Stem Cells

Cytokines are multifunctional small proteins that have a vital influence on inflammatory states of tissues and play a role in signalling and cellular control mechanisms. Cytokine expression has primarily been viewed as a form of direct secretion of molecules through an active transportation; however, other forms of active transport such as extracellular vesicles are at play. This is particularly important in stem cells where signalling molecules are key to communication managing the levels of proliferation, migration, and differentiation into mature cells. This study investigated cytokines from intracellular content, direct cellular secretions, and extracellular vesicles from adult adipose-derived stem cells isolated from three distinct anatomical locations: abdomen, thigh, and chin. The cells were cultured investigated using live cell microscopy, cytokine assays, and bioinformatics analysis. The cytokines quantified and examined from each sample type showed a distinct difference between niche areas and sample types. The varying levels of TNF-alpha, IL-6 and IL-8 cytokines were shown to play a crucial role in signalling pathways such as MAPK, ERK1/2 and JAK-STAT in cells. On the other hand, the chemotactic cytokines IL-1rn, Eotaxin, IP-10 and MCP-1 showed the most prominent changes across extracellular vesicles with roles in noncanonical signalling. By examining the local and tangential roles of cytokines in stem cells, their roles in signalling and in regenerative mechanisms may be further understood.

Mesenchymal Stem Cell Exosomes and Cancer: Controversies and Prospects

Mesenchymal stem cells (MSCs) have displayed a novel therapeutic strategy for a wide range of diseases and conditions. Their secretome and exosome-based paracrine activity are considered as the main processes harboring their diverse therapeutic properties. Several investigations have examined the effects of MSC-derived exosomes on cancer growth, yet, controversial results have always emerged. Although MSC-derived exosomes are able to rigorously enforce the repression of cancer proliferation and progression, it is shown that MSCs exosomal activity displays numerous protumorigenic effects. This discrepancy over the dual effects of MSCs on cancer growth may be mediated by many factors including experimental design, stem cells origins, culture conditions, in addition to cancer-MSCs cross-talks. Despite the controversial effects of MSCs on carcinogenesis, scientists are able to overcome a number of obstacles by modifying MSCs to deliver antioncogenic miRNAs, anticancer drugs, and oncolytic viruses into tumor sites. This review discusses the controversial effects of MSC-derived exosomes on tumorigenesis, investigates the main causes that underlie this discrepancy, summarizes the pattern of engineered-MSCs, and finally highlights how future studies should advance the research in the field of MSCs-based cancer therapies in order to accelerate the transition from preclinical studies to clinical practice.

Human Platelet Lysate Maintains Stemness of Umbilical Cord-Derived Mesenchymal Stromal Cells and Promote Lung Repair in Rat Bronchopulmonary Dysplasia

Mesenchymal stromal cells (MSCs) show potential for treating preclinical models of newborn bronchopulmonary dysplasia (BPD), but studies of their therapeutic effectiveness have had mixed results, in part due to the use of different media supplements for MSCs expansion in vitro. The current study sought to identify an optimal culture supplement of umbilical cord-derived MSCs (UC-MSCs) for BPD therapy. In this study, we found that UC-MSCs cultured with human platelet lysate (hPL-UCMSCs) were maintained a small size from Passage 1 (P1) to P10, while UC-MSCs cultured with fetal bovine serum (FBS-UCMSCs) became wide and flat. Furthermore, hPL was associated with lower levels of senescence in UC-MSCs during in vitro expansion compared with FBS, as indicated by the results of β-galactosidase staining and measures of senescence-related genes (CDKN2A, CDKN1A, and mTOR). In addition, hPL enhanced the proliferation and cell viability of the UC-MSCs and reduced their doubling time in vitro. Compared with FBS-UCMSCs, hPL-UCMSCs have a greater potential to differentiate into osteocytes and chondrocytes. Moreover, using hPL resulted in greater expression of Nestin and specific paracrine factors (VEGF, TGF-β1, FGF2, IL-8, and IL-6) in UC-MSCs compared to using FBS. Critically, we also found that hPL-UCMSCs are more effective than FBS-UCMSCs for the treatment of BPD in a rat model, with hPL leading to improvements in survival rate, lung architecture and fibrosis, and lung capillary density. Finally, qPCR of rat lung mRNA demonstrated that hPL-UCMSCs had lower expression levels of inflammatory factors (TNF-α and IL-1β) and a key chemokine (MCP-1) at postnatal day 10, and there was significant reduction of CD68⁺ macrophages in lung tissue after hPL-UCMSCs transplantation. Altogether, our findings suggest that hPL is an optimal culture supplement for UC-MSCs expansion in vitro, and that hPL-UCMSCs promote lung repair in rat BPD disease.

Roles of mesenchymal stromal cells in the head and neck cancer microenvironment

Head and neck cancer (HNC), a common malignancy worldwide, is associated with high morbidity and mortality rates. Squamous cell carcinoma is the most common HNC type, followed by salivary gland carcinomas, head and neck sarcomas, and lymphomas. The microenvironment of HNCs comprises various cells that regulate tumor development. Recent studies have reported that the tumor microenvironment, which modulates cancer progression, regulates cancer treatment response. However, the presence of different types of stromal cells in cancers is a major challenge to elucidate the role of individual cells in tumor progression. The role of mesenchymal stromal cells (MSCs), which are a component of the tumor microenvironment, in HNC is unclear. The major impediment for characterizing the role of MSCs in cancer progression is the lack of MSC-specific markers and their phenotypic similarity with stromal cells. This review aimed to summarize the latest findings on the role of MSCs in the progression of HNC to improve our understanding of HNC pathophysiology.

Isolation, Culture and Comprehensive Characterization of Biological Properties of Human Urine-Derived Stem Cells

Mesenchymal stem cells (MSCs) represent an attractive source within the field of tissue engineering. However, their harvesting often requires invasive medical procedures. Urine-derived stem cells (UDSCs) display similar properties to MSCs, and their obtention and further processing is non-invasive for the donors as well as low cost. Here, we offer a comprehensive analysis of their biological properties. The goal of this study was to analyze their morphology, stemness, differentiation potential and cytokine profile. We have successfully isolated UDSCs from 25 urine samples. First colonies emerged up to 9 days after the initial seeding. Cell doubling time was 45 ± 0.24 SD, and when seeded at the density of 100 cells/cm², they formed 42 ± 6.5 SD colonies within 10 days. Morphological analyzes revealed that two different types of the cell populations have been present. The first type had a rice-grain shape and the second one was characterized by a polyhedral shape. In several cell cultures, dome-shaped cells were observed as well. All examined UDSCs expressed typical MSC-like surface markers, CD73, CD90 and CD105. Moreover, conditioned media from UDSCs were harvested, and cytokine profile has been evaluated showing a significantly higher secretory rate of IL-8, IL-6 and chemokines MCP-1 and GM-CSF. We have also successfully induced human UDSCs into chondrogenic, osteogenic and myogenic cell lineages. Our findings indicate that UDSCs might have immense potential in the regeneration of the damaged tissues.

Cell-Based Transplantation versus Cell Homing Approaches for Pulp-Dentin Complex Regeneration

Regenerative dentistry has paved the way for a new era for the replacement of damaged dental tissues. Whether the causative factor is dental caries, trauma, or chemical insult, the loss of the pulp vitality constitutes one of the major health problems worldwide. Two regenerative therapies were introduced for a fully functional pulp-dentin complex regeneration, namely, cell-based (cell transplantation) and cell homing (through revascularization or homing by injection of stem cells in situ or intravenously) therapies, with each demonstrating advantages as well as drawbacks, especially in clinical application. The present review is aimed at elaborating on these two techniques in the treatment of irreversibly inflamed or necrotic pulp, which is aimed at regenerating a fully functional pulp-dentin complex.

Aging and Mesenchymal Stem Cells: Therapeutic Opportunities and Challenges in the Older Group

With aging, a portion of cells, including mesenchymal stem cells (MSCs), become senescent, and these senescent cells accumulate and promote various age-related diseases. Therefore, the older age group has become a major population for MSC therapy, which is aimed at improving tissue regeneration and function of the aged body. However, the application of MSC therapy is often unsatisfying in the aged group. One reasonable conjecture for this correlation is that aging microenvironment reduces the number and function of MSCs. Cellular senescence also plays an important role in MSC function impairment. Thus, it is necessary to explore the relationship between senescence and MSCs for improving the application of MSCs in the elderly. Here, we present the influence of aging on MSCs and the characteristics and functional changes of senescent MSCs. Furthermore, current therapeutic strategies for improving MSC therapy in the elderly group are also discussed.

18β-Glycyrrhetinic acid alleviates demyelination by modulating the microglial M1/M2 phenotype in a mouse model of cuprizone-induced demyelination

This research aimed to examine the nutritious supplementary function of 18β-Glycyrrhetinic acid (18β-GA) in moderating the myelin sheath destruction and behavioral impairments observed in the cuprizone model of demyelination. Mice were fed daily on food containing cuprizone (0.3 %) and given doses of 18β-GA (5 or 1 mg/kg) for a period of five weeks. The groups treated with 18β-GA exhibited improvements in exploratory behavior, locomotive activity, and weight. As assessed using luxol-fast blue and myelin basic protein (MBP) staining, which were used to detect demyelination in the brain, 18β-GA both reduced and prevented instances of cuprizone-induced demyelinating lesions; treatment with 18β-GA also caused the MBP level in the corpus callosum to increase. Furthermore, alongside these positive results following 18β-GA treatment, microglial polarisation was also observed to shift towards the beneficial M2 phenotype. The results of this research thus indicate the potential clinical application of 18β-GA for the prevention of myelin damage and behavioral dysfunction.

Effects of continuous passage on the immunomodulatory properties of equine bone marrow-derived mesenchymal stem cells in vitro

BACKGROUND

The immunomodulatory properties of mesenchymal stem cells (MSCs) have been studied extensively due to their increasing clinical application for tissue regeneration and repair following culture expansion. We have studied the effect of continuous passage on the immunomodulatory capacity of equine bone marrow-derived MSCs (BM-MSCs). Equine BM-MSCs were isolated and culture expanded to passage three, six, and nine (P3, P6, P9). Immunomodulatory properties of each passage were assessed using a T cell proliferation assay and cytokine synthesis following stimulation with interferon gamma (IFN-γ).

RESULTS

Equine BM-MSCs maintained their primary cell morphology and immunophenotype throughout all passages. T cell proliferation was suppressed by all passages of BM-MSCs, compared to peripheral blood mononuclear cells (PBMCs) alone. There was no significant difference in suppression of T cell proliferation between P3, P6, and P9 BM-MSCs. All passages of BM-MSCs significantly increased cytokine synthesis in response to stimulation with IFN-γ. There were no significant differences in production of interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) or regulate on activation, normal T cell expressed and secreted (RANTES) following stimulation with IFN-γ between P3, P6, and P9 BM-MSCs. P9 BM-MSCs had significantly increased production of tumor necrosis factor alpha (TNF-α), (IL-1β), and (IL-10) compared to P3 BM-MSCs. Additionally, there was a significant increase in production of (IL-8) in P6 and P9 BM-MSCs in comparison to P3 BM-MSCs.

CONCLUSIONS

Our findings demonstrate that culture expansion affects some of the immunomodulatory properties of BM-MSCs in vitro, which may suggest that MSCs isolated from a single collection of bone marrow may be culture expanded, but only those from lower passage numbers would be ideal for clinical application.

Mechanobiological Principles Influence the Immune Response in Regeneration: Implications for Bone Healing

A misdirected or imbalanced local immune composition is often one of the reasons for unsuccessful regeneration resulting in scarring or fibrosis. Successful healing requires a balanced initiation and a timely down-regulation of the inflammation for the re-establishment of a biologically and mechanically homeostasis. While biomaterial-based approaches to control local immune responses are emerging as potential new treatment options, the extent to which biophysical material properties themselves play a role in modulating a local immune niche response has so far been considered only occasionally. The communication loop between extracellular matrix, non-hematopoietic cells, and immune cells seems to be specifically sensitive to mechanical cues and appears to play a role in the initiation and promotion of a local inflammatory setting. In this review, we focus on the crosstalk between ECM and its mechanical triggers and how they impact immune cells and non-hematopoietic cells and their crosstalk during tissue regeneration. We realized that especially mechanosensitive receptors such as TRPV4 and PIEZO1 and the mechanosensitive transcription factor YAP/TAZ are essential to regeneration in various organ settings. This indicates novel opportunities for therapeutic approaches to improve tissue regeneration, based on the immune-mechanical principles found in bone but also lung, heart, and skin.

Discarded plasma obtained after cord blood volume reduction as an alternative for fetal calf serum in mesenchymal stromal cells cultures

BACKGROUND

Utilization of the fetal calf serum (FCS) carries a potential health risk and raises growing economic and ethical problems. Umbilical cord blood volume reduction, required for banking, provides clinical-grade umbilical cord blood plasma (UCBP) discarded as a waste. The aim of this study was to test whether serum derived from UCBP could replace FCS for the amplification of mesenchymal stromal cells (MSCs).

STUDY DESIGN AND METHODS

To this end, the amplification of the MSCs and mesenchymal progenitors was estimated in the presence of serum derived from UCBP and its cytokine content was determined by cytometric bead array and enzyme-linked immunosorbent assay techniques. As a comparison, other sources of clinical-grade human serum were tested in parallel: serum derived from solvent/detergent-treated fresh-frozen plasma (S/D-FFP) and from platelet (PLT)-rich and PLT-poor umbilical plasma.

RESULTS

Serum derived from UCBP-supplemented culture sustains identical amplification of MSCs and their progenitors as in the case of FCS addition. Furthermore, the assays reveal the presence in the serum derived from UCBP of cytokines influencing the properties of MSCs (basic fibroblast growth factor, transforming growth factor-β, vascular endothelial growth factor, and interleukin-8) or involved in the development of the myeloid lineage (thrombopoietin, erythropoietin, granulocyte-colony-stimulating factor, and granulocyte-macrophage-colony-stimulating factor). Also, our study indicates important differences between neonatal and adult-derived serum. Poor cytokine content in the S/D-FFP makes a less efficient replacement of FCS comparing to other human blood-derived supplements.

CONCLUSION

Our work shows that the discarded human cord blood plasma from volume reduction is an easily obtainable and greatly available, xeno-free source of serum that is a highly efficient replacement of FCS in sustaining MSC growth.

Transcriptional profiling reveals altered biological characteristics of chorionic stem cells from women with gestational diabetes

Background

Gestational diabetes (GDM) is a common complication of pregnancy. The impact of pregnancy complications on placental function suggests that extraembryonic stem cells in the placenta may also be affected during pregnancy. Neonatal tissue-derived stem cells, with the advantages of their differentiation capacity and non-invasive isolation processes, have been proposed as a promising therapeutic avenue for GDM management through potential cell therapy approaches. However, the influence of GDM on autologous stem cells remains unclear. Thus, studies that provide comprehensive understanding of stem cells isolated from women with GDM are essential to guide future clinical applications.

Methods

Human chorionic membrane-derived stem cells (CMSCs) were isolated from placentas of healthy and GDM pregnancies. Transcriptional profiling was performed by DNA microarray, and differentially regulated genes between GDM- and Healthy-CMSCs were used to analyse molecular functions, differentiation, and pathway enrichment. Altered genes and biological functions were validated via real-time PCR and in vitro assays.

Results

GDM-CMSCs displayed, vs. Healthy-CMSCs, 162 upregulated genes associated with increased migration ability, epithelial development, and growth factor-associated signal transduction while the 269 downregulated genes were strongly linked to angiogenesis and cellular metabolic processes. Notably, significantly reduced expression of detoxification enzymes belonging to the aldehyde dehydrogenase gene families (ALDH1A1/1A2, ALDH2, ALDH3) accounted for downregulation across several metabolic pathways. ALDH activity and inhibitor assays indicated that reduced gene expression of ALDHs affected ALDH enzymatic functions and resulted in oxidative stress dysregulation in GDM-CMSCs.

Conclusion

Our combined transcriptional analysis and in vitro functional characterisation have provided novel insights into fundamental biological differences in GDM- and Healthy-CMSCs. Enhanced mobility of GDM-CMSCs may promote MSC migration toward injured sites; however, impaired cellular metabolic activity may negatively affect any perceived benefit.

Nonadherent culture method promotes MSC-mediated vascularization in myocardial infarction via miR-519d/VEGFA pathway

BACKGROUND

Mesenchymal stem cells (MSCs) can provide therapeutic benefits for myocardial infarction (MI) recovery; however, the molecular mechanism by which MSCs improve the heart function is unclear.

METHODS

Microarray analysis was performed to examine the expression profiling of human MSCs (hMSCs) grown as adherent cultures (AC-hMSCs) or nonadherent cultures on ultra-low-adherent plates (nonAC-hMSCs). Real-time quantitative polymerase chain reaction (RT-qPCR), western blotting, and enzyme-linked immunosorbent assays (ELISA) were used to assess VEGFA expression and secretion in the AC-hMSCs and nonAC-hMSCs. The paracrine effect of VEGFA-overexpressing AC-MSCs (AC-VEGFA-hMSCs) or VEGFA-knockdown nonAC-hMSCs (nonAC-shVEGFA-hMSCs) on the angiogenic ability of human umbilical vein endothelial cells (HUVECs) was evaluated using tube formation assay. AC-VEGFA-hMSCs or nonAC-shVEGFA-hMSCs were transplanted into myocardial infarction rats to investigate the therapeutic effect of AC-VEGFA-hMSCs or nonAC-shVEGFA-hMSCs. Luciferase reporter assay was used to confirm the association of VEGFA with miR-519d.

RESULTS

Microarray analysis revealed that VEGFA is downregulated in AC-hMSCs compared to nonAC-hMSCs. Functional assays revealed that high levels of VEGFA produced from AC-VEGFA-hMSCs increased the tube formation capacity of HUVECs in vitro, improved angiogenesis and cardiac performance, and reduced infarct size in a rat MI model. Low levels of VEGFA secretion from nonAC-shVEGFA-hMSCs had the opposite effects. Mechanistically, we found that miR-519d directly targets VEGFA. High levels of VEGFA secreted from VEGFA-overexpressing nonAC-hMSCs abolished the repressive effect of miR-519d on HUVEC angiogenesis.

CONCLUSION

Our findings indicate that nonadherent culture-induced secretion of VEGFA plays an important role in MSCs via the miR-519d/VEGFA pathway and may provide a novel therapeutic strategy for MI treatment.

Biological Considerations in Scaling Up Therapeutic Cell Manufacturing

Cell therapeutics - using cells as living drugs - have made advances in many areas of medicine. One of the most clinically studied cell-based therapy products is mesenchymal stromal cells (MSCs), which have shown promising results in promoting tissue regeneration and modulating inflammation. However, MSC therapy requires large numbers of cells, the generation of which is not feasible via conventional planar tissue culture methods. Scale-up manufacturing methods (e.g., propagation on microcarriers in stirred-tank bioreactors), however, are not specifically tailored for MSC expansion. These processes may, in principle, alter the cell secretome, a vital component underlying the immunosuppressive properties and clinical effectiveness of MSCs. This review outlines our current understanding of MSC properties and immunomodulatory function, expansion in commercial manufacturing systems, and gaps in our knowledge that need to be addressed for effective up-scaling commercialization of MSC therapy.

Pro-inflammatory Cytokines in Acute Coronary Syndromes

BACKGROUND

Over the last decades, the role of inflammation and immune system activation in the initiation and progression of coronary artery disease (CAD) has been established.

OBJECTIVES

The study aimed to present the interplay between cytokines and their actions preceding and shortly after ACS.

METHODS

We searched in a systemic manner the most relevant articles to the topic of inflammation, cytokines, vulnerable plaque and myocardial infarction in MEDLINE, COCHRANE and EMBASE databases.

RESULTS

Different classes of cytokines (intereleukin [IL]-1 family, Tumor necrosis factor-alpha (TNF-α) family, chemokines, adipokines, interferons) are implicated in the entire process leading to destabilization of the atherosclerotic plaque, and consequently, to the incidence of myocardial infarction. Especially IL-1 and TNF-α family are involved in inflammatory cell accumulation, vulnerable plaque formation, platelet aggregation, cardiomyocyte apoptosis and adverse remodeling following the myocardial infarction. Several cytokines such as IL-6, adiponectin, interferon-γ, appear with significant prognostic value in ACS patients. Thus, research interest focuses on the modulation of inflammation in ACS to improve clinical outcomes.

CONCLUSION

Understanding the unique characteristics that accompany each cytokine-cytokine receptor interaction could illuminate the signaling pathways involved in plaque destabilization and indicate future treatment strategies to improve cardiovascular prognosis in ACS patients.

The effect of interleukin-8 in the early stage after anterior cruciate ligament reconstruction with remnant preservation

PURPOSE

We studied the effect of interleukin-8 (IL-8) as the factor for angiogenesis in the joint fluid of remnant-preserved anterior cruciate ligament reconstruction (RP-ACLR).

MATERIALS AND METHODS

We measured 12 cytokines in joint fluid by multiplex assay and assessed the relationship between IL-8 and vascular endothelial growth factor (VEGF) concentrations. The signal intensity and mean sagittal diameter via postoperative magnetic resonance imaging (MRI) scans were evaluated and the stress X-ray image was analyzed at 3, 6, and 12 months after operation.

RESULTS

The IL-8 concentration was highest 3 months postoperatively in those patients who underwent RP-ACLR. Clinical data also showed that the signal intensity and stress radiography of the knee graft were significantly better at the early postoperative stage.

DISCUSSION

Our results show that IL-8 plays an important role in angiogenesis within 3 months after RP-ACLR. This effect yields better recovery after operation. RP-ACLR patients with high knee stability in clinical data were identical to those with high expression of IL-8 in experimental data. Therefore, IL-8 has been shown to help revascularization and ligamentization of the grafted tendon. These results indicate that IL-8 in RP-ACLR is an important factor for angiogenesis after operation. Unfortunately, the relationship of IL-8 and VEGF in vivo has not been studied.

CONCLUSION

Our results showed that the IL-8 concentration was very high within 3 months after RP-ACLR operation. The increase in concentration of IL-8 over time was consistent with the increase in VEGF concentration. In the IL-8 clinical setting, MRI analysis showed that ACL synovialization and tension were better in patients who underwent the remnant preservation method. In addition, it was shown that RP-ACLR may be advantageous for early anterior stability within 1 year post operation and beneficial for tendon graft in the early stage post operation. Taken together, our findings suggest that IL-8 may contribute to angiogenesis which is helpful for revascularization and ligamentization of the graft tendon in the early stages of RP-ACLR.

Role of some members of chemokine/cytokine network in the pathogenesis of thalassemia and sickle cell hemoglobinopathies: a mini review

The word of hemoglobinopathy is described for an array of disorders that affecting hemoglobin (Hb) functions. Hb is a molecule with 68 kDa molecular weight, serving as oxygen carrying metalloprotein. Hemoglobinopathy includes a wide range of Hb structural deficits varying from thalassemia to sickle cell disease. Cyto-chemokine network members are pivotally involved in the pathogenesis of hemoglobinopathies, however, the exact role of these mediators in the development of these disorders yet to be well addressed. Cytokines and chemokines are generated by inflamed endothelial cells that promote the expression of their respected receptors and further activate NF-κβ, recruit red blood cells (RBCs) and white blood cells (WBCs) toward the inflamed endothelium. Therefore, due to critical roles played by the cyto-chemokine network in several aspects of hemoglobinopathies pathophysiology including apoptosis of endothelial cells, RBC, WBC and etc.…, in the present review, we focused on the critical parts played by this network in the pathogenesis of hemoglobinopathies.

Proteomic Identification and Time-Course Monitoring of Secreted Proteins During Expansion of Human Mesenchymal Stem/Stromal in Stirred-Tank Bioreactor

The therapeutic potential of mesenchymal stem/stromal cells (MSC) is widely recognized for the treatment of several diseases, including acute graft-vs.-host disease (GVHD), hematological malignancies, cardiovascular, bone, and cartilage diseases. More recently, this therapeutic efficacy has been attributed to the bioactive molecules that these cells secrete (secretome), now being referred as medicinal signaling cells. This fact raises the opportunity of therapeutically using MSC-derived soluble factors rather than cells themselves, enabling their translation into the clinic. Indeed, many clinical trials are now studying the effects of MSC-secretome in the context of cell-free therapy. MSC secretome profile varies between donors, source, and culture conditions, making their therapeutic use very challenging. Therefore, identifying these soluble proteins and evaluating their production in a reproducible and scalable manner is even more relevant. In this work, we analyzed the global profile of proteins secreted by umbilical cord matrix (UCM) derived-MSC in static conditions by using mass spectrometry, enabling the identification of thousands of proteins. Afterwards, relevant proteins were chosen and monitored in the supernatant of a fully-controllable, closed and scalable system (bioreactor) by using multiple reaction monitoring (MRM) mass spectrometric technique in a time-dependent manner. The results showed that the majority of interesting proteins were enriched through time in culture, with the last day of culture being the ideal time for supernatant collection. The use of this regenerative "soup," which is frequently discarded, could represent a step toward a safe, robust and reproducible cell-free product to be used in the medical therapeutic field. The future use of chemically defined culture-media will certainly facilitate secretome production according to Good Manufacturing Practice (GMP) standards.

Disease-specific primed human adult stem cells effectively ameliorate experimental atopic dermatitis in mice

Although human mesenchymal stem cells (hMSCs) hold considerable promise as an alternative therapeutic reagent for allergic disorders including atopic dermatitis (AD), the strategy for enhancing hMSC-based therapy remains challenging. We sought to investigate whether preconditioning with mast cell (MC) granules could enhance the therapeutic efficiency of human umbilical cord blood-derived MSCs (hUCB-MSCs) against AD.

Methods: AD was experimentally induced in NC/Nga mice by repeated applications of 4% sodium dodecyl sulfate (SDS) and dermatophagoides farinae (Df) extract, and preconditioned hUCB-MSCs were subcutaneously injected. The therapeutic effect was determined by gross examination and additional ex vivo experiments performed using blood and skin samples to determine the resolution of allergic inflammation. To explore the underlying mechanisms, several co-culture assays with primary isolated immune cells and wound closure assays were conducted.

Results: Pretreatment of MC granules enhanced the therapeutic effects of hUCB-MSCs by attenuating the symptoms of AD in an experimental animal model. MC granule-primed cells suppressed the activation of major disease-inducing cells, MCs and B lymphocytes more efficiently than naïve cells both in vitro and in vivo. Histamine-mediated upregulation of the COX-2 signaling pathway was shown to play a crucial role in suppression of the allergic immune response by MC-pretreated hUCB-MSCs. Moreover, MC pretreatment improved the wound healing ability of hUCB-MSCs.

Conclusions: Our findings indicate that pre-exposure to MC granules improved the therapeutic effect of hUCB-MSCs on experimental AD by resolving the allergic immune reaction and accelerating the tissue regeneration process more efficiently than naïve cells, suggesting a potential enhancement strategy for stem cell-based therapy.

Mesenchymal Stromal Cell Homing: Mechanisms and Strategies for Improvement

Mesenchymal stromal cells (MSCs) have been widely investigated for their therapeutic potential in regenerative medicine, owing to their ability to home damaged tissue and serve as a reservoir of growth factors and regenerative molecules. As such, clinical applications of MSCs are reliant on these cells successfully migrating to the desired tissue following their administration. Unfortunately, MSC homing is inefficient, with only a small percentage of cells reaching the target tissue following systemic administration. This attrition represents a major bottleneck in realizing the full therapeutic potential of MSC-based therapies. Accordingly, a variety of strategies have been employed in the hope of improving this process. Here, we review the molecular mechanisms underlying MSC homing, based on a multistep model involving (1) initial tethering by selectins, (2) activation by cytokines, (3) arrest by integrins, (4) diapedesis or transmigration using matrix remodelers, and (5) extravascular migration toward chemokine gradients. We then review the various strategies that have been investigated for improving MSC homing, including genetic modification, cell surface engineering, in vitro priming of MSCs, and in particular, ultrasound techniques, which have recently gained significant interest. Contextualizing these strategies within the multistep homing model emphasizes that our ability to optimize this process hinges on our understanding of its molecular mechanisms. Moving forward, it is only with a combined effort of basic biology and translational work that the potential of MSC-based therapies can be realized.

The Role of the Stem Cells Therapy in the Peripheral Artery Disease

Vascular complications of diabetes mellitus are an important issue for all clinicians involved in the management of this complex pathology. Although many therapeutic advances have been reached, peripheral arterial disease is still an unsolved problem that each year compromises the quality of life and life span of affected patients. Oftentimes, patients, after ineffective attempts of revascularization, undergo greater amputations. At the moment, there is no effective and definitive treatment available. In this scenario, the therapeutic use of stem cells could be an interesting option. The aim of the present review is to gather all the best available evidence in this regard and to define a new role of the stem cells therapy in this field, from biomarker to possible therapeutic target.

Preconditioning of Human Dental Pulp Stem Cells with Leukocyte- and Platelet-Rich Fibrin-Derived Factors Does Not Enhance Their Neuroregenerative Effect

Pathologies of the central nervous system are characterized by loss of brain tissue and neuronal function which cannot be adequately restored by endogenous repair processes. This stresses the need for novel treatment options such as cell-based therapies that are able to restore damaged tissue or stimulate repair. This study investigated the neuroregenerative potential of the conditioned medium of human dental pulp stem cells (CM-hDPSCs) on neural stem cell (NSC) proliferation and migration as well as on neurite outgrowth of primary cortical neurons (pCNs). Additionally, the effect of leukocyte- and platelet-rich fibrin (L-PRF) priming on the neuroregenerative potential of the hDPSC secretome on NSCs and pCNs was evaluated. L-PRF contains factors that enhance stem cell-induced regeneration, but its effect on hDPSC-mediated neuroregeneration is unknown. This study demonstrated that CM-hDPSCs enhanced neuritogenesis. Moreover, CM-hDPSCs had a chemoattractant effect on NSCs. Although priming hDPSCs with L-PRF increased brain-derived neurotrophic factor secretion, no additional effects on the paracrine-mediated repair mechanisms were observed. These data support the neuroregenerative potential of hDPSCs, and although priming had no additional effect, the potential of L-PRF-primed hDPSCs on distinct regenerative mechanisms remains to be clarified.

Mesenchymal stem cells and the neuronal microenvironment in the area of spinal cord injury

Cell-based technologies are used as a therapeutic strategy in spinal cord injury (SCI). Mesenchymal stem cells (MSCs), which secrete various neurotrophic factors and cytokines, have immunomodulatory, anti-apoptotic and anti-inflammatory effects, modulate reactivity/phenotype of astrocytes and the microglia, thereby promoting neuroregeneration seem to be the most promising. The therapeutic effect of MSCs is due to a paracrine mechanism of their action, therefore the survival of MSCs and their secretory phenotype is of particular importance. Nevertheless, these data are not always reported in efficacy studies of MSC therapy in SCI. Here, we provide a review with summaries of preclinical trials data evaluating the efficacy of MSCs in animal models of SCI. Based on the data collected, we have tried (1) to establish the behavior of MSCs after transplantation in SCI with an evaluation of cell survival, migration potential, distribution in the area of injured and intact tissue and possible differentiation; (2) to determine the effects MSCs on neuronal microenvironment and correlate them with the efficacy of functional recovery in SCI; (3) to ascertain the conditions under which MSCs demonstrate their best survival and greatest efficacy.

Biologically produced silver chloride nanoparticles from B. megaterium modulate interleukin secretion by human adipose stem cell spheroids

Stem cell tissue constructs are likely to come into contact with silver-based nanoparticles-such as silver chloride nanoparticles (AgCl-NPs)-used as microbicidals at the implant site or in cosmetics. However, the effect of silver-based nanoparticles on 3D cell cultures with potential for tissue engineering has received little attention. Here, we examined the effect of sub-lethal doses (5, 10 and 25 µg/mL, for 1, 7 and 21 days) of AgCl-NPs produced by 'green' bacterial-based synthesis on spheroid 3D cultures of human adipose tissue stem cells (ASCs). Light microscopy analysis revealed that the shape and diameter of ASC spheroids remained largely unchanged after AgCl-NP treatment. Flow cytometry analysis with 7-AAD and 2',7'-dichlorofluorescein diacetate revealed no statistically significant differences in cell death but showed an increase of ROS levels for the untreated group and significant differences for the groups treated with 5 and 10 µg/mL at day 7 (p = 0.0395, p = 0.0266, respectively). Electron microscopy analysis showed limited cell damage in the periphery of AgCl-NP-treated spheroids. However, treatment with AgCl-NP had statistically significant effects on the secretion of IL-6, IL-8, IL-1β and IL-10 by spheroids, at specific treatment periods and concentrations, and particularly for IL-6, IL-8 and IL-1β. TGF-β1 and -β2 secretion also changed significantly throughout the treatment period. Our results indicate that, despite having little effect on cell viability and morphology, sub-lethal AgCL-NP doses modulate ROS production at day 7 for the groups treated with 5 and 10 µg/mL and also modulate the secretory profile of ASC spheroids. Thus, the use of skin implants or products containing Ag-NPs may promote long-term disturbances in subcutaneous adipose tissue homeostasis.

Bioinspired Designs, Molecular Premise and Tools for Evaluating the Ecological Importance of Antimicrobial Peptides

This review article provides an overview of recent developments in antimicrobial peptides (AMPs), summarizing structural diversity, potential new applications, activity targets and microbial killing responses in general. The use of artificial and natural AMPs as templates for rational design of peptidomimetics are also discussed and some strategies are put forward to curtail cytotoxic effects against eukaryotic cells. Considering the heat-resistant nature, chemical and proteolytic stability of AMPs, we attempt to summarize their molecular targets, examine how these macromolecules may contribute to potential environmental risks vis-à-vis the activities of the peptides. We further point out the evolutional characteristics of the macromolecules and indicate how they can be useful in designing target-specific peptides. Methods are suggested that may help to assess toxic mechanisms of AMPs and possible solutions are discussed to promote the development and application of AMPs in medicine. Even if there is wide exposure to the environment like in the hospital settings, AMPs may instead contribute to prevent healthcare-associated infections so long as ecotoxicological aspects are considered.

Dynamics of tissue ingrowth in SIKVAV-modified highly superporous PHEMA scaffolds with oriented pores after bridging a spinal cord transection

While many types of biomaterials have been evaluated in experimental spinal cord injury (SCI) research, little is known about the time-related dynamics of the tissue infiltration of these scaffolds. We analyzed the ingrowth of connective tissue, axons and blood vessels inside the superporous poly (2-hydroxyethyl methacrylate) hydrogel with oriented pores. The hydrogels, either plain or seeded with mesenchymal stem cells (MSCs), were implanted in spinal cord transection at the level of Th8. The animals were sacrificed at days 2, 7, 14, 28, 49 and 6 months after SCI and histologically evaluated. We found that within the first week, the hydrogels were already infiltrated with connective tissue and blood vessels, which remained stable for the next 6 weeks. Axons slowly and gradually infiltrated the hydrogel within the first month, after which the numbers became stable. Six months after SCI we observed rare axons crossing the hydrogel bridge and infiltrating the caudal stump. There was no difference in the tissue infiltration between the plain hydrogels and those seeded with MSCs. We conclude that while connective tissue and blood vessels quickly infiltrate the scaffold within the first week, axons show a rather gradual infiltration over the first month, and this is not facilitated by the presence of MSCs inside the hydrogel pores. Further research which is focused on the permissive micro-environment of the hydrogel scaffold is needed, to promote continuous and long-lasting tissue regeneration across the spinal cord lesion.

Gametocytes of the Malaria Parasite Plasmodium falciparum Interact With and Stimulate Bone Marrow Mesenchymal Cells to Secrete Angiogenetic Factors

The gametocytes of Plasmodium falciparum, responsible for the transmission of this malaria parasite from humans to mosquitoes, accumulate and mature preferentially in the human bone marrow. In the 10 day long sexual development of P. falciparum, the immature gametocytes reach and localize in the extravascular compartment of this organ, in contact with several bone marrow stroma cell types, prior to traversing the endothelial lining and re-entering in circulation at maturity. To investigate the host parasite interplay underlying this still obscure process, we developed an in vitro tridimensional co-culture system in a Matrigel scaffold with P. falciparum gametocytes and self-assembling spheroids of human bone marrow mesenchymal cells (hBM-MSCs). Here we show that this co-culture system sustains the full maturation of the gametocytes and that the immature, but not the mature, gametocytes adhere to hBM-MSCs via trypsin-sensitive parasite ligands exposed on the erythrocyte surface. Analysis of a time course of gametocytogenesis in the co-culture system revealed that gametocyte maturation is accompanied by the parasite induced stimulation of hBM-MSCs to secrete a panel of 14 cytokines and growth factors, 13 of which have been described to play a role in angiogenesis. Functional in vitro assays on human bone marrow endothelial cells showed that supernatants from the gametocyte mesenchymal cell co-culture system enhance ability of endothelial cells to form vascular tubes. These results altogether suggest that the interplay between immature gametocytes and hBM-MSCs may induce functional and structural alterations in the endothelial lining of the human bone marrow hosting the P. falciparum transmission stages.

Hyperglycemia induced testicular damage in type 2 diabetes mellitus rats exhibiting microcirculation impairments associated with vascular endothelial growth factor decreased via PI3K/Akt pathway

As an endocrine disease, type 2 diabetes mellitus (T2DM) can cause testicular damage which induces male infertility. However, the underlying mechanism is still not clear. We prove that T2DM induced testicular microcirculation impairment involves the decrease of VEGF and these actions are regulated by PI3K/Akt pathway. In our study, rats were divided into three groups (n=8): control group, diabetes group and diabetes + VEGF group. Intraperitoneal injection of streptozotocin (STZ, 65mg/Kg, at 9^th week) and daily high-fat diet were used to establish T2DM rat model. Serum glucose in diabetes group and diabetes + VEGF group obviously exceeded 13mmol/L after STZ injection. Immunohistochemical studies indicated that VEGF level in diabetes group significantly decreased. In diabetes group, testicular blood velocity and vascular area reduced evaluated by Doppler and FITC. Furthermore, atrophic testicular morphology and increasing apoptosis cells were evaluated by haematoxylin and eosin staining and TUNEL assay. In diabetes + VEGF group, the administration of VEGF (intraperitoneally, 10mg/kg) can significantly alleviated hyperglycemia-induced impairment of testes in above aspects. Finally, we used Western blot to analyze the mechanism of hyperglycemia-induced testicular VEGF decrease. The results indicated that hyperglycemia-induced VEGF decreased is regulated by PI3K/Akt pathway in Rats testicular sertoli cells (RTSCs). Together, we demonstrate that T2DM can reduce testicular VEGF expression, which results in testicular microcirculation impairment, and then induces testicular morphological disarrangement and functional disorder. These actions are triggered by PI3K/Akt pathway. Our findings provide solid evidence for VEGF becoming a therapeutic target in T2DM related male infertility.