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Stem cell therapy has recently progressed from the preclinical to the early clinical trial arena for a variety of diseases. Moreover, the medical students lack the deep and full understanding of its significance and potential as the promising future cure for diverse diseases worldwide. This study aims at evaluating the knowledge, awareness, and perception of medical students as far as stem cells applications are related in the medical field. A cross-sectional survey was carried out using online questionnaires, which were distributed via e-mail to cover all medical faculties in Jordan. The data show that medical students are supportive of using stem cells and their therapeutic applications, and most of them are willing and enthusiastically want to improve their knowledge about stem cells; however, due to the tight schedule and the lack of an elective course about stem cells in the curriculum, many of them are not ready to undergo further training in regenerative medicine unless it becomes part of the assigned training and part of the learning objectives for medical students. These findings indicated the need to update the medical school curriculum with new hits in medicine and expand the range of courses offered for medical students so they can be up-to-date with the quick advances in different medical disciplines.

Barth Syndrome is a rare X-linked genetic disorder caused by mutations in theTAFAZZINgene. We recently demonstrated that tafazzin (Taz) protein deficiency in murine mesenchymal stems (MSCs) reduces immune function of activated wild type (WT) B lymphocytes. Interleukin-10 (IL-10) is a key anti-inflammatory cytokine capable of exerting immunosuppressive effects on myeloid cells. Here we examined if Taz deficiency in murine MSCs altered proliferation and IL-10 production in Taz deficient lipopolysaccharide (LPS)-activated murine B lymphocytes. Bone marrow MSCs and splenic B lymphocytes were isolated from WT or Taz knockdown (TazKD) mice. WT or Taz deficient MSCs were co-cultured with either LPS-activated WT or LPS-activated Taz deficient B lymphocytes for 24 h and B cell proliferation and IL-10 production determined. Taz deficient MSCs exhibited increased phosphatidylinositol-3-kinase (PI3K) mRNA expression compared to WT MSCs indicative of enhanced immunosuppression. Co-culture of Taz deficient MSCs with Taz deficient LPS-activated B cells resulted in a greater reduction in proliferation of B cells compared to Taz deficient MSCs co-cultured with LPS-activated WT B cells. In addition, co-culture of Taz deficient MSCs with Taz deficient LPS-activated B cells resulted in an enhanced production of IL-10 compared to Taz deficient MSCs co-cultured with LPS-activated WT B cells. Thus, Taz deficiency in murine MSCs potentiates the Taz knockdown-mediated elevation in IL-10 secretion from LPS-activated Taz knockdown B lymphocytes. These data suggest that Taz deficient MSCs may modulate the activity of other Taz deficient immune cells potentially promoting an enhanced immunosuppressive state.

Nicotine dependence has deleterious neurological impacts. Previous studies found an association between cigarette smoking and accelerating age-related thinning of the brain's cortex and subsequent cognitive decline. Smoking is considered the third most common risk factor for dementia, which prompted the inclusion of smoking cessation in dementia prevention strategies. Traditional pharmacologic options for smoking cessation include nicotine transdermal patches, bupropion and varenicline. However, based on smokers’ genetic makeup, pharmacogenetics can be used to develop novel therapies to replace these traditional approaches. Genetic variability of cytochrome P450 2A6 has a major impact on smokers’ behavior and their response to quitting therapies. Gene polymorphism in nicotinic acetylcholine receptor subunits also has a great influence on the ability to quit smoking. In addition, polymorphism of certain nicotinic acetylcholine receptors was found to affect the risk of dementia and the impact of tobacco smoking on the development of Alzheimer's disease. Nicotine dependence involves the activation of pleasure response through the stimulation of dopamine release. Central dopamine receptors, catechol-o-methyltransferase and the dopamine transporter protein, regulate synaptic dopamine levels. The genes of these molecules are potential targets for novel smoking cessation drugs. Pharmacogenetic studies of smoking cessation also investigated other molecules, such as ANKK1 and dopamine-beta-hydroxylase (DBH). In this perspective article, we aim to highlight the promising role of pharmacogenetics in the development of effective drugs for smoking cessation, which can increase the success rate of smoking quitting plans and ultimately reduce the incidence of neurodegeneration and dementia.

Background: The thalamus, are large, gray masses that act as an evolved sensory and motor gateway to the cortex. The thalamus has been implicated in the pathophysiology of several illnesses. In this study we measure and compare the size of thalamus and interthalamic adhesion using magnetic resonance imaging (MRI) between normal, Alzheimer’s and multiple sclerosis Arab patients. Moreover, we assess the gender differences and right-left differences of the thalamus and interthalamic adhesion in all three groups Materials and methods: This prospective study was used T1-weighted brain magnetic resonance images (MRI) to measure the anteroposterior, transvers and vertical length of the thalamic and interthalamic adhesion. The MRI scan were obtained from 150 (75 males and 75 females) healthy participants, 100 (52 males and 48 females) Alzheimer’s patients, and a 100 (56 males and 44 females) multiple sclerosis patients. Results: The thalamus and interthalamic adhesion size were significantly reduce in both Alzheimer’s and multiple sclerosis patients comparing to healthy controls. There was no correlation between gender or right-left sides and the dimensions of the thalamus and interthalamic adhesion within the same disease group. Conclusion: The study showed a correlation between some neurodegenerative disorder and the thalamus and interthalamic adhesion size. The gender and the right-left sides not effecting the thalamus and interthalamic adhesion size within the same neurodegenerative disorder group.

Abstract: Alzheimer’s disease (AD) is considered one of the most complicated neurodegenerative disorders, and it is associated with progressive memory loss and remarkable neurocognitive dysfunction that negatively impacts the ability to perform daily living activities. AD accounts for an estimated 60-80% of dementia cases. AD's previously known pathological basis is the deposition of amyloid β (Aβ) aggregates and the formation of neurofibrillary tangles by tau hyperphosphorylation in the cell bodies of neurons that are located in the hippocampus, neocortex, and certain other regions of the cerebral hemispheres and limbic system. The lack of neurotransmitter acetylcholine and the activation of oxidative stress cascade may also contribute to the pathogenesis of AD. These pathological events can lead to irreversible loss of neuronal networks and the emergence of memory impairment and cognitive dysfunction that can engender an abnormal change in the personality. AD cannot be cured, and to some extent, the prescribed medications can only manage the symptoms associated with this disease. Several studies have reported that the regenerative abilities of neural stem/progenitor cells (NSCs) remarkably decline in AD, which disturbs the balancing power to control its progression. Exogenous infusion or endogenous activation of NSCs may be the ultimate solution to restore the neuronal networks in the brain of AD patients and regenerate the damaged areas responsible for memory and cognition. In this mini-review, we will touch upon the fate of NSCs in AD and the utilization of neurogenesis using modified NSCs to restore cognitive functions in AD.

Magnetic Nanoparticles (MNPs) have gained interest within the research community due to their therapeutic potential in a variety of medical applications. MNPs are generally composed of a metallic core stabilized by the addition of an outer shell that can be further functionalized through the absorbance or conjugation of various targeting ligands. The magnetic properties of these nanoparticles can be utilized for imaging, localized drug delivery, and enhanced diagnostic detection. This chapter highlights the applications of MNPs to enhance magnetic resonance imaging (MRI) capabilities and improve the delivery of therapeutic agents to difficult-to-reach areas in the body. In addition, recent advances in the use of MNPs in stem cell therapy for both the tracking and monitoring of stem cell distribution in the body and improving engraftment and differentiation in stem cell therapy are discussed. Finally, examples of the incorporation of MNPs in diagnostic assays to improve rapid and realtime detection capabilities of many diseases, including cancer, cardiovascular diseases, and pathogen infections, are provided.

Allogeneic mesenchymal stem cells (MSCs) from young and healthy donors are immunoprivileged and have the potential to treat numerous degenerative diseases. However, recent reviews of clinical trials report poor long-term survival of transplanted cells in the recipient that turned down the enthusiasm regarding MSC therapies. Increasing evidence now confirm that though initially immunoprivileged, MSCs eventually become immunogenic after transplantation in the ischemic or hypoxic environment of diseased tissues and are rejected by the host immune system. We performed in vitro (in rat and human cells) and in vivo (in a rat model) investigations to understand the mechanisms of the immune switch in the phenotype of MSCs. The immunoprivilege of MSCs is preserved by the absence of cell surface immune antigen, major histocompatibility complex II (MHC-II) molecule. We found that the ATPase subunit of 19S proteasome "Sug1" regulates MHC-II biosynthesis in MSCs. Exposure to hypoxia upregulates Sug1 in MSCs and its binding to class II transactivator (CIITA), a coactivator of MHC-II transcription. Sug1 binding to CIITA in hypoxic MSCs promotes the acetylation and K63 ubiquitination of CIITA leading to its activation and translocation to the nucleus, and ultimately MHC-II upregulation. In both rat and human MSCs, knocking down Sug1 inactivated MHC-II and preserved immunoprivilege even following hypoxia. In a rat model of myocardial infarction, transplantation of Sug1-knockdown MSCs in ischemic heart preserved immunoprivilege and improved the survival of transplanted cells. Therefore, the current study provides novel mechanisms of post-transplantation loss of immunoprivilege of MSCs. This study may help in facilitating better planning for future clinical trials.

Allogeneic mesenchymal stem cells (MSCs) are immunoprivileged and are being investigated in phase I and phase II clinical trials to treat different degenerative and autoimmune diseases. In spite of encouraging outcome of initial trials, the long-term poor survival of transplanted cells in the host tissue has declined the overall enthusiasm. Recent analyses of allogeneic MSCs based studies confirm that after transplantation in the hypoxic or ischemic microenvironment of diseased tissues, MSCs become immunogenic and are rejected by recipient immune system. The immunoprivilege of MSCs is preserved by absence or negligible expression of cell surface antigen, human leukocyte antigen (HLA)-DRα. We found that in normoxic MSCs, 26S proteasome degrades HLA-DRα and maintains immunoprivilege of MSCs. The exposure to hypoxia leads to inactivation of 26S proteasome and formation of immunoproteasome in MSCs, which is associated with upregulation and activation of HLA-DRα, and as a result, MSCs become immunogenic. Furthermore, inhibition of immunoproteasome formation in hypoxic MSCs preserves the immunoprivilege. Therefore, hypoxia-induced shift in the phenotype of proteasome from 26S toward immunoproteasome triggers loss of immunoprivilege of allogeneic MSCs. The outcome of the current study may provide molecular targets to plan interventions to preserve immunoprivilege of allogeneic MSCs in the hypoxic or ischemic environment.

Mesenchymal stem cells (MSCs) are regarded as unique cells which play an imperative role in the field of regenerative medicine. They are characterized by the self-renewal capacity, multi-lineage differentiation abilities and immunomodulation properties which render them perfectly ideal cell type for treating a wide range of chronic diseases. Despite these enchanted features, there are many hurdles that need to be circumvented to ensure their long-term survival and viability after transplantation. Recently, hypoxia has been indicated as one of the most baffling stress conditions that can affect the survival rate of MSCs either positively or negatively depending on the level of hypoxia. MSCs can survive well under moderate hypoxia, but die shortly if they were exposed to severe hypoxia without clearly convincing explanation for this enigma. The current study reveals a novel mechanism of 26S proteasome in controlling the ability of BM-MSCs to withstand hypoxic stress by maintaining proper mitochondrial function. The results indicated that 26S proteasome remains functioning once BM- MSCs are exposed to moderate hypoxia (2.5%O2) and preserves their survival and proliferation mediated by intact mitochondrial performance, whereas 26S proteasome becomes inactive when BM-MSCs faces severe hypoxia that lead to poor mitochondrial function and less chance to survive longer. The outcomes of this study demonstrated the importance of 26S proteasome machinery in enhancing the resistance of BM-MSCs to hypoxic stress condition which may help in better planning future studies that target this system. Schematic representation summarizing the findings of the current study. 26S proteasome function preservation in normoxia and moderate hypoxia leads to maintain appropriate proliferation and mitochondrial activity in human BM-MSCs and promote their survival. On the opposite side, severe hypoxia disrupts the 26S proteasome function leading to significant reduction in the proliferation, survival and mitochondrial dynamics in human BM-MSCs causing their death.

B lymphocytes are responsible for humoral immunity and play a key role in the immune response. Optimal mitochondrial function is required to support B cell activity during activation. We examined how deficiency of tafazzin, a cardiolipin remodeling enzyme required for mitochondrial function, alters the metabolic activity of B cells and their response to activation by lipopolysaccharide in mice. B cells were isolated from 3-month-old wild type or tafazzin knockdown mice and incubated for up to 72 h with lipopolysaccharide and cell proliferation, expression of cell surface markers, secretion of antibodies and chemokines, proteasome and immunoproteasome activities, and metabolic function determined. In addition, proteomic analysis was performed to identify altered levels of proteins involved in survival, immunogenic, proteasomal and mitochondrial processes. Compared to wild type lipopolysaccharide activated B cells, lipopolysaccharide activated tafazzin knockdown B cells exhibited significantly reduced proliferation, lowered expression of cluster of differentiation 86 and cluster of differentiation 69 surface markers, reduced secretion of immunoglobulin M antibody, reduced secretion of keratinocytes-derived chemokine and macrophage-inflammatory protein-2, reduced proteasome and immunoproteasome activities, and reduced mitochondrial respiration and glycolysis. Proteomic analysis revealed significant alterations in key protein targets that regulate cell survival, immunogenicity, proteasomal processing and mitochondrial function consistent with the findings of the above functional studies. The results indicate that the cardiolipin transacylase enzyme tafazzin plays a key role in regulating mouse B cell function and metabolic activity during activation through modulation of mitochondrial function.

Barth Syndrome (BTHS) is a rare X-linked genetic disorder caused by mutation in the TAFAZZIN gene which encodes the cardiolipin (CL) transacylase tafazzin (Taz). Taz deficiency in BTHS patients results in reduced CL in their tissues and a neutropenia which contributes to the risk of infections. However, the impact of Taz deficiency in other cells of the immune system is poorly understood. Mesenchymal stem cells (MSCs) are well known for their immune inhibitory function. We examined whether Taz-deficiency in murine MSCs impacted their ability to modulate lipopolysaccharide (LPS)-activated wild type (WT) murine B lymphocytes. MSCs from tafazzin knockdown (TazKD) mice exhibited a 50% reduction in CL compared to wild type (WT) MSCs. However, mitochondrial oxygen consumption rate and membrane potential were unaltered. In contrast, TazKD MSCs exhibited increased glycolysis compared to WT MSCs and this was associated with elevated proliferation, phosphatidylinositol-3-kinase expression and expression of the immunosuppressive markers indoleamine-2,3-dioxygenase, cytotoxic T-lymphocyte-associated protein 4, interleukin-10, and cluster of differentiation 59. When co-cultured with LPS-activated WT B cells, TazKD MSCs inhibited B cell proliferation and growth rate and reduced B cell secretion of IgM to a greater extent than B cells co-cultured with WT MSCs. In addition, co-culture of LPS-activated WT B cells with TazKD MSCs induced B cell differentiation toward potent immunosuppressive phenotypes including interleukin-10 secreting plasma cells and B regulatory cells compared to activated B cells co-cultured with WT MSCs. These results indicate that Taz deficiency in MSCs enhances MSCs-mediated immunosuppression of activated B lymphocytes.

B lymphocytes are responsible for humoral immunity and play a key role in the immune response. Optimal mitochondrial function is required to support B cell activity during activation. We examined how deficiency of tafazzin, a cardiolipin remodeling enzyme required for mitochondrial function, alters the metabolic activity of B cells and their response to activation by lipopolysaccharide in mice. B cells were isolated from 3 month old wild type or tafazzin knockdown mice and incubated for up to 72 h with lipopolysaccharide and cell proliferation, expression of cell surface markers, secretion of antibodies and chemokines, proteasome and immunoproteasome activities, and metabolic function determined. In addition, proteomic analysis was performed to identify altered levels of proteins involved in survival, immunogenic, proteasomal and mitochondrial processes. Compared to wild type lipopolysaccharide activated B cells, lipopolysaccharide activated tafazzin knockdown B cells exhibited significantly reduced proliferation, lowered expression of cluster of differentiation 86 and cluster of differentiation 69 surface markers, reduced secretion of immunoglobulin M antibody, reduced secretion of keratinocytes-derived chemokine and macrophage-inflammatory protein-2, reduced proteasome and immunoproteasome activities, and reduced mitochondrial respiration and glycolysis. Proteomic analysis revealed significant alterations in key protein targets that regulate cell survival, immunogenicity, proteasomal processing and mitochondrial function consistent with the findings of the above functional studies. The results indicate that the cardiolipin transacylase enzyme tafazzin plays a key role in regulating mouse B cell function and metabolic activity during activation.

Ischemic heart disease is a growing worldwide epidemic. Improvements in medical and surgical therapies have reduced early mortality after acute myocardial infarction and increased the number of patients living with chronic heart failure. The irreversible loss of functional cardiomyocytes puts these patients at significant risk of ongoing morbidity and mortality after their index event. Recent evidence suggests that inflammation is a key mediator of postinfarction adverse remodeling in the heart. In this review, we discuss the cardioprotective and deleterious effects of inflammation and its mediators during acute myocardial infarction. We also explore the role of mesenchymal stem cell therapy to limit secondary injury and promote myocardial healing after myocardial infarction.

Increasing reports of successful and safe application of bone marrow derived mesenchymal stem cells (BM-MSCs) for cell therapy are pouring in from numerous studies. However poor survival of transplanted cells in the recipient has impaired the benefits of BM-MSCs based therapies. Therefore cell product preparation procedures pertaining to MSC therapy need to be optimized to improve the survival of transplanted cells. One of the important ex vivo procedures in the preparation of cells for therapy is passaging of BM-MSCs to ensure a suitable number of cells for transplantation, which may affect the turnover of proteins involved in regulation of cell survival and (or) death pathways. In the current study, we investigated the effect of an increase in passage number of BM-MSCs in cell culture on the intracellular protein turnover (protein synthesis, processing, and degradation machinery). We performed proteomic analysis of BM-MSCs at different passages. There was no significant difference observed in the ribosomal, protein processing, and proteasomal pathways related proteins in BM-MSCs with an increase in passage number from P3 to P7. Therefore, expansion of MSCs in the cell culture in clinically relevant passages (Passage 3–7) does not affect the quality of MSCs in terms of intracellular protein synthesis and turnover.

Human mesenchymal stem cells (MSCs) are presently on the top of hierarchy in the field of stem cell therapy, due to their miraculous therapeutic abilities in diminishing the symptoms of many chronic diseases and initiating regeneration and repair for various damaged tissues and organs. The foremost initial step to reach high success rate in any MSCs based study is the optimization of culture growth media by establishing a suitable fetal bovine serum (FBS) percentage that suits the purpose of MSCs based experiment. Choosing the suitable FBS percentage is a controversial issue and merely depends on the researchers experience and suggested recommendations by the suppliers. Despite the huge improvements in overall MSCs investigating approaches, there are no definite protocols that set up a range of FBS percentages that can be followed. Toward achieving this objective, we evaluate in the present report the effect of using various FBS percentages (5-20%) added to DMEM low glucose media, on the biological behaviour of MSCs. Growing MSCs in high FBS percentages containing culture media (15% and 20% FBS) increase the proliferation and expansion rate of MSCs, although it decreases the immunosuppressive properties. On the other hand, adding low FBS percentage (7% FBS) to MSCs culture media enhanced the immunosuppression characteristics of MSCs, even though the proliferation rate was moderately reduced. 7% FBS is the cut off percentage that can be used without negatively altering major MSCs biological properties in which using 5% FBS will cause a tremendous decrease in the proliferation capacity and immunosuppressive properties. This report may assist other researchers in choosing appropriate FBS percentage when preparing MSCs culture media that serve the purpose of their MSCs based studies.

Lysosomal acid phosphatase 2 (Acp2) mutant mice (naked-ataxia, nax) have a severe cerebellar cortex defect with a striking reduction in the number of granule cells. Using a combination of in vivo and in vitro immunohistochemistry, Western blotting, BrdU assays, and RT-qPCR, we show downregulation of MYCN and dysregulation of the SHH signaling pathway in the nax cerebellum. MYCN protein expression is significantly reduced at P10, but not at the peak of proliferation at around P6 when the number of granule cells is strikingly reduced in the nax cerebellum. Despite the significant role of the SHH–MycN pathway in granule cell proliferation, our study suggests that a broader molecular pathway and additional mechanisms regulating granule cell development during the clonal expansion period are impaired in the nax cerebellum. In particular, our results indicate that downregulation of the protein synthesis machinery may contribute to the reduced number of granule cells in the nax cerebellum.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or coronavirus disease 2019 (COVID-19) pandemic has exhausted the health systems in many countries with thousands cases diagnosed daily. The currently used treatment guideline is to manage the common symptoms like fever and cough, but doesn't target the virus itself or halts serious complications arising from this viral infection. Currently, SARS-CoV-2 exhibits many genetic modulations which have been associated with the appearance of highly contagious strains. The number of critical cases of COVID-19 increases markedly, and many of the infected people die as a result of respiratory failure and multiple organ dysfunction. The regenerative potential of mesenchymal stem cells (MSCs) has been extensively studied and confirmed. The impressive immunomodulation and anti-inflammatory activity of MSCs have been recognized as a golden opportunity for the treatment of COVID-19 and its associated complications. Moreover, MSCs regenerative and repairing abilities have been corroborated by many studies with positive outcomes and high recovery rates. Based on that, MSCs infusion could be an effective mechanism in managing and stemming the serious complications and multiple organ failure associated with COVID-19. In the present review, we discuss the commonly reported complications of COVID-19 viral infection and the established and anticipated role of MSCs in managing these complications.

There has been considerable attention paid to cutaneous stem cell in the area of regenerative medicine as a potential therapeutic goal for managing disorders of the skin and hair, possible use in quickening or supporting the process of wound healing, and numerous types of cancers related to the skin. Cutaneous stem cell plays an essential role in many processes as skin structures’ renovation in case of injuries. During hemostasis, the growth of hair follicles and melanocytes is reconstructed and produced. So, obtaining applicable and valid access to skin stem cells for cutaneous interventions, which often include active molecules, is a treasured accomplishment. However, the main hindrance for drug delivery through the topical route is the active barrier represented by the skin against most exogenous molecules’ penetration. Thus, this field's research is paying more attention to new strategies to avoid and by-pass this barrier efficiently. In this section, a summary of recent advancements made in stem cell and an investigation of their benefits.

Bone marrow derived allogeneic (donor derived) mesenchymal stem cells (MSCs) are considered to be prominent cell type for cardiac repair following a damage due to ischemic heart disease. Even though the outcome of initial allogeneic MSCs based clinical trials was encouraging, the overall enthusiasm lately has declined due to poor survival of transplanted cells in the ischemic heart. We reported in a rat model of myocardial infarction that allogeneic-MSCs became immunogenic after 5 weeks of transplantation and were rejected by host immune system that led to poor survival of implanted cells. The immunoprivilege of MSCs is preserved by absence of cell surface antigen, human leukocyte antigen (HLA) - DRα. We found that in normoxic MSCs, 26S proteasome degrades HLA-DRα and maintains immunoprivilege of MSCs. The exposure to hypoxia leads to inactivation of 26S proteasome and formation of immunoproteasome in MSCs, which is associated with upregulation and activation of HLA-DRα, and as a result MSCs become immunogenic. Furthermore, inhibition of immunoproteasome formation in hypoxic MSCs preserves the immunoprivilege. Therefore, hypoxia induced shift in the phenotype of proteasome from 26S toward immunoproteasome triggers loss of immunoprivilege of allogeneic MSCs and rejection. In our ongoing studies we are investigating if preventing the formation of immunoproteasome would prevent rejection of allogeneic MSCs in the ischemic heart and improve survival of transplanted cells. The outcome of these studies may provide molecular targets to plan interventions to preserve immunoprivilege of allogeneic MSCs in the ischemic heart and improve benefits of allogeneic MSCs for cardiac repair.

Allogeneic mesenchymal stem cells (MSCs) from young and healthy donors are reported to hold the potential to treat several immunological and degenerative disorders. However, recent data from animal studies and clinical trials demonstrate that immunogenicity and poor survival of transplanted MSCs impaired the efficacy of cells for regenerative applications. It is reported that initially immunoprivileged under in vitro conditions, MSCs are targeted by the host immune system after transplantation in the ischemic tissues in vivo. We performed in vitro (in MSCs) and in vivo (in the rat model of myocardial infarction [MI]) studies to elucidate the mechanisms responsible for the change in the immunophenotype of MSCs from immunoprivileged to immunogenic under ischemic conditions. We have recently reported that a soluble factor prostaglandin E2 (PGE2) preserves the immunoprivilege of allogeneic MSCs. In the current study, we found that PGE2 levels, which were elevated during normoxia, decreased in MSCs following exposure to hypoxia. Further, we found that proteasome-mediated degradation of cyclooxygenase-2 (COX2, rate-limiting enzyme in PGE2 biosynthesis) in hypoxic MSCs is responsible for PGE2 decrease and loss of immunoprivilege of MSCs. While investigating the mechanisms of COX2 degradation in hypoxic MSCs, we found that in normoxic MSCs, COP9 signalosome subunit 5 (CSN5) binds to COX2 and prevents its degradation by the proteasome. However, exposure to hypoxia leads to a decrease in CSN5 levels and its binding to COX2, rendering COX2 protein susceptible to proteasome-mediated degradation. This subsequently causes PGE2 downregulation and loss of immunoprivilege of MSCs. Maintaining COX2 levels in MSCs preserves immunoprivilege in vitro and improves the survival of transplanted MSCs in a rat model of MI. These data provide novel mechanistic evidence that PGE2 is downregulated in hypoxic MSCs which is responsible for the post-transplantation rejection of allogeneic MSCs. Therefore, our data suggest that the new strategies that target CSN5-COX2 signaling may improve survival and utility of transplanted allogeneic MSCs in the ischemic heart.

The poor survival of transplanted allogeneic mesenchymal stem cells (MSCs) in the recipient heart has dampened the overall enthusiasm of allogeneic MSCs based clinical trials. Outcome of recent studies suggests that the phenotype of transplanted cells changes from immunoprivileged to immunogenic state that leads to rejection of implanted cells by host immune system. In this study, we present a novel mechanism of immune switch in MSCs. We found that hypoxia/or ischemic environment shifts immunological landscape of MSCs from immunoprivileged to immunogenic state. The immunoprivilege of MSCs is preserved by absence of major histocompatibility complex class II (MHC-II) molecule. Our studies demonstrate that 26S proteasome-mediated degradation of MHC-II prevents its expression on cell surface in MSCs and preserves their immunoprivilege. The exposure to hypoxia results in dissociation of 19S and 20S subunits, and inactivation of 26S proteasome. This promotes accumulation of MHC-II and increases immunogenicity of MSCs. We also found that a chaperon protein HSP90α is responsible for 26S proteasome activity in normoxic MSCs. The level of HSP90α decreases in hypoxic MSCs that leads to increase in immunogenicity. Maintaining HSP90α levels in hypoxic MSCs prevents 26S inactivation and preserves immunoprivilege of MSCs. Therefore, hypoxia-induced defects in 26S proteasome assembly causes loss of immunoprivilege of allogeneic MSCs. Preserving 26S proteasome activity in MSCs maintains immunoprivilege and prevents rejection of allogeneic MSCs in the heart. (This work was supported by CIHR)

Inflammation is tightly linked to tissue injury. In regenerative medicine, immune activation plays a key role in rejection of transplanted stem cells and reduces the efficacy of stem cell therapies. Next-generation smart biomaterials are reported to possess multiple biologic properties for tissue repair. Here, the first use of 0D titanium carbide (Ti

The quadriceps angle (Q angle), formed between the quadriceps muscles and the patella tendon, is considered clinically as a very important parameter which displays the biomechanical effect of the quadriceps muscle on the knee, and it is also regarded a crucial factor for the proper posture and movement of the knee patella. The Q angle is routinely and regularly used as an assessment parameter during the diagnosis of many knee-related problems, including the anterior knee pain, osteoarthritis, and degenerative knee disorders. This study had been conducted so as to measure the normal Q angle values range in the Arab nationalities and determine the correlation between Q angle values and several body parameters, including gender, height, weight, dominant side, and the condylar distance of the femur. The study includes 500 healthy young Arab students from the Yarmouk University and Jordan University of Science and Technology. The Q angle of those volunteers was measured using a universal manual Goniometer with the subjects in the upright weight-bearing position. It was found that Q angle was greater in young women than young men. Also, the analysis of the data revealed an insignificant increase in the dominant side of the Q angle. In addition, the Q angle was significantly higher in the taller people of both sexes. However, the Q angle did not present any considerable correlation with weight in the study population; conversely, it was clearly observed that there was a link with the condylar distance of the femur in both sexes. It was also noticed that the Q angle increased remarkably when there was an increase in the condylar distance. Consequently, it turned out that the gender, height, and the condylar distance were momentous factors that had impact on the Q angle in our study samples. However, weight and dominancy factors did not show to have any influence on the values in our study.

Background It has been estimated that up to 50% of any patient population is at least partially non-adherent to their prescribed treatment. Identifying barriers to adherence is required to develop effective interventions for psychiatric patients. Objective To explore the prevalence and factors of non-adherence among psychiatric patients present at four psychiatric clinics. Method A cross-sectional questionnaire-based study. A sample of psychiatric patients attending outpatient psychiatric clinics was enrolled between March and April 2011. Results A total of 243 psychiatric patients took part in this study with the majority of patients (92.5%) being prescribed more than one psychiatric disorder. The majority (64.2%) of the patients was classified as non-adherent according to the Morisky adherence questionnaire and forgetfulness was the most prevalent reason for that. Conclusions Non-adherence is a common and important issue among psychiatric patients. Polypharmacy, safety concerns and lack of insight towards the prescribed treatment were reported as the main reasons of non-adherence.

Abnormal conduction and improper electrical impulse propagation are common in heart after myocardial infarction (MI). The scar tissue is non-conductive therefore the electrical communication between adjacent cardiomyocytes is disrupted. In the current study, we synthesized and characterized a conductive biodegradable scaffold by incorporating graphene oxide gold nanosheets (GO-Au) into a clinically approved natural polymer chitosan (CS). Inclusion of GO-Au nanosheets in CS scaffold displayed two fold increase in electrical conductivity. The scaffold exhibited excellent porous architecture with desired swelling and controlled degradation properties. It also supported cell attachment and growth with no signs of discrete cytotoxicity. In a rat model of MI, in vivo as well as in isolated heart, the scaffold after 5 weeks of implantation showed a significant improvement in QRS interval which was associated with enhanced conduction velocity and contractility in the infarct zone by increasing connexin 43 levels. These results corroborate that implantation of novel conductive polymeric scaffold in the infarcted heart improved the cardiac contractility and restored ventricular function. Therefore, our approach may be useful in planning future strategies to construct clinically relevant conductive polymer patches for cardiac patients with conduction defects.

Allogeneic mesenchymal stem cells (MSCs) derived from bone marrow are considered to ideal candidate cell type for myocardial repair after a cardiac injury. However, recent reviews of allogeneic MSCs based clinical trials reported that transplanted cells were not able to survive for long term in the heart. Therefore, strategies to improve survival of transplanted cells would preserve the benefits of allogeneic MSCs therapy for heart repair. Recently, graphene oxide (GO) based biomaterials are being widely investigated for their ability to improve survival of transplanted MSCs in the heart. However, the presence of reactive oxygen functional groups (-OH, -COOH) in the structure of GO increases oxidative stress and activate cell death pathways, which impairs the benefits of GO based biomaterials. Therefore, to improve benefits of GO for stem cell delivery, we synthesized a thermosensitive hydrogel by conjugating GO with chitosan (CS). Our fourier transformed infrared spectrum (FTIR) analysis revealed an interaction between oxygen functional groups of GO and amino (-NH2) groups of chitosan. Our data demonstrate that CS masked the reactive functional groups of GO and prevented GO mediated ROS induction. This novel chitosan-graphene oxide (CS-GO) composite exhibited optimal porosity for cell conjugation and retention. Furthermore, CS-GO biomaterial was cyto-compatible as there was no cytotoxicity caused by CS-GO to MSCs. Furthermore, CS-GO also prevented hypoxia induced apoptosis of MSCs. We employed this novel biomaterial to deliver allogeneic MSCs to the infarcted heart in a rat model of myocardial infarction. After 5 weeks of cell transplantation, there was a significant improvement in the survival of implanted MSCs and cardiac function in CS-GO group. Therefore, conjugation of GO with chitosan prevented GO mediated ROS generation and cell death. Also, CS-GO mediated delivery of allogeneic MSCs to infarcted heart improved the survival of transplanted cells and preserved cardiac function.

Background Bone marrow-derived allogeneic mesenchymal stem cells (MSCs) from young healthy donors are immunoprivileged and their clinical application for regenerative medicine is under evaluation. However, data from preclinical and initial clinical trials indicate that allogeneic MSCs after transplantation provoke a host immune response and are rejected. In the current study, we evaluated the effect of an increase in passage number in cell culture on immunoprivilege of the MSCs. Since only limited numbers of MSCs can be sourced at a time from a donor, it is imperative to expand them in culture to meet the necessary numbers required for cell therapy. Presently, the most commonly used passages for transplantation include passages (P)3–7. Therefore, in this study we included clinically relevant passages, i.e., P3, P5, and P7, for evaluation. Methods The immunoprivilege of MSCs was assessed with the mixed leukocyte reaction assay, where rat MSCs were cocultured with peripheral blood leukocytes for 72 h. Leukocyte-mediated cytotoxicity, apoptosis (Bax/Bcl-xl ratio), leukocyte proliferation, and alterations in cellular bioenergetics in MSCs were assessed after the coculture. Furthermore, the expression of various oxidized phospholipids (oxidized phosphatidylcholine (ox-PC)) was analyzed in MSCs using a lipidomic platform. To determine if the ox-PCs were acting in tandem with downstream intracellular protein alterations, we performed proteome analysis using a liquid chromatography/mass spectrometry (LC/MS) proteomic platform. Results Our data demonstrate that MSCs were immunoprivileged at all three passages since coculture with leukocytes did not affect the survival of MSCs at P3, P5, and P7. We also found that, with an increase in the passage number of MSCs, leukocytes did not cause any significant effect on cellular bioenergetics (basal respiration rate, spare respiratory capacity, maximal respiration, and coupling efficiency). Interestingly, in our omics data, we detected alterations in some of the ox-PCs and proteins in MSCs at different passages; however, these changes were not significant enough to affect their immunoprivilege. Conclusions The outcome of this study demonstrates that an increase in passage number (from P3 to P7) in the cell culture does not have any significant effect on the immunoprivilege of MSCs. Electronic supplementary material The online version of this article (10.1186/s13287-018-0867-4) contains supplementary material, which is available to authorized users.

Figure S1. Differentiation of MSCs into osteocytes, adipocytes, and chondrocytes. MSCs were induced to differentiate toward osteocytes (a), adipocytes (b), and chondrocytes (c). MSCs (undifferentiated cells, control group) and differentiated MSCs (D-MSC) were stained for osteocalcin and Alizarin Red (osteocyte lineage), FABP4 and Oil Red-O stain (adipocyte lineage), and aggrecan (chondrocyte lineage). The images were taken using Cytation5 (BioTek Instruments) (20Ă magnification). (nâ =â 6) (PPTX 2648 kb)

Figure S2. Heat map showing the highly upregulated or downregulated proteins that are known to be associated with mitochondrial respiration and immune pathways at P3 versus P7. (PPTX 5354 kb)

This chapter is based on a simplified method to validate the current preservation procedure of mesenchymal stem cells (MSCs). Currently, there are various media available for freezing and thus preserving the MSCs, making it hard to decide which agent will be apt for cellular requirements. The study describes the effect of two different compositions of freezing media used in regular cell culture experiments, on the morphology, proliferation, and doubling rate of MSCs. Commonly used agents for the cryopreservation of MSCs include DMSO (Dimethyl Sulfoxide) and FBS (Fetal Bovine Serum) and DMEM (Dulbecco's Modified Eagle Medium). To ascertain that the currently used agents do not lead to major changes in the MSC morphology and proliferation, the cells are frozen using the above-mentioned agents in different groups and then their effects analyzed. Thus, the chapter helps to decide what reagents can suit the MSCs, hence minimizing the laboratory to laboratory variability of their characteristics.

Mesenchymal stem cells (MSCs) provide an opportunity to bring the field of regenerative medicine to realization. A lot of clinical trials are presently trying to establish their applicability in real-world scenarios. Some of the biggest challenges encountered in bringing MSCs from bench to bedside are the number of MSCs required, their procurement from various sources, and the batch-to-batch variability. This often leads to inconclusive results within and between different studies. Therefore, we have hereby proposed a simple protocol to source mesenchymal stem cells through differentiation of embryonic stem cells.

This chapter is based on a simplified method to validate the current preservation procedure of mesenchymal stem cells (MSCs). Currently, there are various media available for freezing and thus preserving the MSCs, making it hard to decide which agent will be apt for cellular requirements. The study describes the effect of two different compositions of freezing media used in regular cell culture experiments, on the morphology, proliferation, and doubling rate of MSCs. Commonly used agents for the cryopreservation of MSCs include DMSO (Dimethyl Sulfoxide) and FBS (Fetal Bovine Serum) and DMEM (Dulbecco's Modified Eagle Medium). To ascertain that the currently used agents do not lead to major changes in the MSC morphology and proliferation, the cells are frozen using the above-mentioned agents in different groups and then their effects analyzed. Thus, the chapter helps to decide what reagents can suit the MSCs, hence minimizing the laboratory to laboratory variability of their characteristics.

Inflammation is tightly linked to tissue injury. In regenerative medicine, immune activation plays a key role in rejection of transplanted stem cells and reduces the efficacy of stem cell therapies. Next-generation smart biomaterials are reported to possess multiple biologic properties for tissue repair. Here, the first use of 0D titanium carbide (Ti3 C2 ) MXene quantum dots (MQDs) for immunomodulation is presented with the goal of enhancing material-based tissue repair after injury. MQDs possess intrinsic immunomodulatory properties and selectively reduce activation of human CD4+ IFN-γ+ T-lymphocytes (control 87.1 ± 2.0%, MQDs 68.3 ± 5.4%) while promoting expansion of immunosuppressive CD4+ CD25+ FoxP3+ regulatory T-cells (control 5.5 ± 0.7%, MQDs 8.5 ± 0.8%) in a stimulated lymphocyte population. Furthermore, MQDs are biocompatible with bone marrow-derived mesenchymal stem cells and induced pluripotent stem cell-derived fibroblasts. Finally, Ti3 C2 MQDs are incorporated into a chitosan-based hydrogel to create a 3D platform with enhanced physicochemical properties for stem cell delivery and tissue repair. This composite hydrogel demonstrates increased conductivity while maintaining injectability and thermosensitivity. These findings suggest that this new class of biomaterials may help bridge the translational gap in material and stem cell-based therapies for tissue repair and treatment of inflammatory and degenerative diseases.

Introduction Doxorubicin (DOX) is a well-known anticancer drug. However its clinical use has been limited due to cardiotoxic effects. One of the major concerns with DOX therapy is its toxicity in patients who are frail, particularly diabetics. Several studies suggest that mesenchymal stem cells (MSCs) have the potential to restore cardiac function after DOX-induced injury. However, limited data are available on the effects of MSC therapy on DOX-induced cardiac dysfunction in diabetics. Our objective was to test the efficacy of bone marrow-derived (BM-MSCs) and adipose-derived MSCs (AT-MSCs) from age-matched humans in a non-immune compromised rat model. Methods Diabetes mellitus was induced in rats by streptozotocin injection (STZ, 65 mg/kg b.w, i.p.). Diabetic rats were treated with DOX (doxorubicin hydrochloride, 2.5 mg/kg b.w, i.p) 3 times/wk for 2 weeks (DOX group); or with DOX+ GFP labelled BM-MSCs (2x106cells, i.v.) or with DOX + GFP labelled AT-MSCs (2x106cells, i.v.). Echocardiography and Langendorff perfusion analyses were carried out to determine the heart function. Immunostaining and western blot analysis of the heart tissue was carried out for CD31 and to assess inflammation and fibrosis. Statistical analysis was carried out using SPSS and data are expressed as mean ± SD. Results Glucose levels in the STZ treated groups were significantly greater than control group. After 4 weeks of intravenous injection, the presence of injected MSCs in the heart was confirmed through fluorescent microscopy and real time PCR for ALU transcripts. Both BM-MSCs and AT-MSCs injection prevented DOX-induced deterioration of %FS, LVDP, dp/dt max and rate pressure product. Staining for CD31 showed a significant increase in the number of capillaries in BM-MSCs and AT-MSCs treated animals in comparison to DOX treated group. Assessment of the inflammation and fibrosis revealed a marked reduction in the DOX-induced increase in immune cell infiltration, collagen deposition and αSMA in the BM-MSCs and AT-MSCs groups. Conclusions In conclusion BM-MSCs and AT-MSCs were equally effective in mitigating DOX-induced cardiac damage by promoting angiogenesis, decreasing the infiltration of immune cells and collagen deposition.

Background: It is now established that having diabetes not only increases the chances of cancer also it complicates cancer treatment therapy. Doxorubicin (DOX) is a well known anticancer drug, however the clinical use of DOX was limited due to its cardiotoxic effects. One of the major concerns with DOX therapy has been its toxicity in patients who are less robust and more prone to toxic side effects, particularly patients with comorbid diseases such as diabetes mellitus. Several studies have demonstrated that mesenchymal stem cell (MSC) therapy has the potential to restore cardiac function following DOX induced cardiac injury. However, there is no study available on the effects of MSC therapy on DOX induced cardiac dysfunction in diabetics. Methods and Results: Diabetes was induced in male Wistar rats by streptozotcin injection (STZ, 65mg/kg body weight, i.p.). After 4 weeks of STZ injection, blood glucose levels in STZ group (301.58±23.97mg/dl) were significantly greater than control group (83.51±7.91mg/dl). These diabetic rats were treated with adriamycin (2.5mg/kg body weight, i.p) 3 times/week for two weeks (AD group); or with adriamycin+bone marrow MSCs (BM-MSC; 2x106 cells, via tail vein) or with adriamycin+adipose tissue derived MSCs (AD-MSC; 2x106 cells, via tail vein). Echocardiographic measurements showed a significant decline in cardiac function (%EF) following adriamycin treatment. Both BM-MSC and AT-MSC treatment improved %EF at 4 weeks. After 4 weeks of MSC injection, hearts from all the groups were excised and subjected to retrograde Langendorff perfusion and baseline levels of left ventricular developed pressure (LVDP), maximum rate of pressure rise dp/dt max and rate pressure product (RPP) were recorded. AD treatment caused a significant decrease in LVDP, dp/dt max and RPP levels. Both BM-MSCs and AD-MSCs injection significantly improved all these parameters. Conclusion: Both BM-MSC and AT-MSC were equally effective in preventing deterioration of cardiac function following doxorubicin therapy in diabetic rats. Furthermore, these findings should act as a stimulus for further research on the benefits of MSC therapy for diabetic subjects suffering from cancer.