Comparing the effect of using 2-Mercaptoethanol in the cell culture medium of different cell passages of human mesenchymal stem cells.

Preparing a suitable cell culture medium that supports the biological needs of the growing cells is crucial to enhancing the success rate of any in vitro and in vivo experiments and minimizing undesirable interferences.  Mesenchymal stem cells ( MSCs) which are powerful regenerative stem cells require being grown in proper culture media to preserve their stemness and therapeutic properties. MSCs are usually grown in Dulbecco's Modified Eagle low glucose Medium (DMEM low glucose) which contains 5.6 mmol/L of glucose and is supplemented with Fetal Bovine Serum (FBS), antibiotics, and 2-Mercaptoethanol. The addition of 2-Mercaptoethanol to the cell culture medium was proposed long ago and has continued to be used until now. Despite the positive effects of adding 2-Mercaptoethanol in the cell culture medium, its use is still controversial and needs continuous updates to limit its interference with experimental treatments. Herein, we found that 2-Mercaptoethanol is beneficial to enhancing the proliferation and survival of MSCs at higher passage numbers while its effect is negligible for earlier passages. This concise study provides updates regarding the suitable time to add 2-Mercaptoethanol which can minimize its intermeddling with the experimental design and treatments.

Adipose Tissue and Bone Marrow-Derived Mesenchymal Stem Cells are not Really the Same: Investigating the Differences in Their Immunomodulatory, Migratory, and Adhesive Profile.

Mesenchymal stem cells (MSCs) are the most widely used stem cells in regenerative medicine. They can be isolated from multiple sources, most commonly bone marrow and adipose tissue. MSCs derived from different sources show similar molecular and biological characteristics, but there is ongoing debate regarding the best source of MSCs and the potential biological differences between MSCs from different origins. Bone marrow derived-MSCs (BM-MSCs) and adipose tissue-derived MSCs (AD-MSCs) share many molecular and immunomodulatory properties. In this study, we compared the levels of major immunomodulatory, adhesive, and migratory factors in human BM-MSCs and AD-MSCs under normal conditions, which will help determine the suitability and specificity of each type for certain therapeutic applications. WST1 assay and fluorescent assay SUC-LLVY-AMC were used to measure MSC proliferation and 26S proteasome activity, respectively. Western blotting, ELISA Assays, and bright field live imaging were also used. AD-MSCs and BM-MSCs exhibited similar morphology and proliferation rate. A significantly higher 26S proteasome activity was detected in AD-MSCs than in BM-MSCs. Levels of ICAM-1, integrin α5 and integrin α6 were significantly higher in AD-MSCs compared to BM-MSCs, while no significant difference in CXCR4 levels was observed. Expression of IDO and factor H was significantly higher in AD-MSCs, while CTLA-4 and IL-10 levels were higher in BM-MSCs. This indicates that AD-MSCs and BM-MSCs have different immunomodulatory and adhesion profiles. MSCs isolated from different sources may show differences in their biological and immunomodulatory properties, suggesting a potential suitability of certain MSCs type for specific conditions. Also, combination of different MSCs types could help optimize therapeutic outcomes.

Addressing the impact of high glucose microenvironment on the immunosuppressive characteristics of human mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are a therapeutically efficient type of stem cells validated by their ability to treat many inflammatory and chronic conditions. The biological and therapeutic characteristics of MSCs can be modified depending on the type of microenvironment at the site of transplantation. Diabetes mellitus (DM) is a commonly diagnosed metabolic disease characterized by hyperglycemia, which alters over time the cellular and molecular functions of many cells and causes their damage. Hyperglycemia can also impact the success rate of MSCs transplantation; therefore, it is extremely significant to investigate the effect of high glucose on the biological and therapeutic attributes of MSCs, particularly their immunomodulatory abilities. Thus, in this study, we explored the effect of high glucose on the immunosuppressive characteristics of human adipose tissue-derived mesenchymal stem cells (hAD-MSCs). We found that hAD-MSCs cultured in high glucose lost their immunomodulatory abilities and became detectable by immune cells. The decline in the immunosuppressive capabilities of hAD-MSCs was mediated by significant decrease in the levels of IDO, IL-10, and complement factor H and substantial increase in the activity of immunoproteasome. The protein levels of AMP-activated protein kinase (AMPK) and phosphofructokinase-1 (PFK-1), which are integral regulators of glycolysis, revealed a marked decline in high glucose exposed MSCs. The findings of our study indicated the possibility of immunomodulatory shift in MSCs after being cultured in high glucose, which can be translationally employed to explain their poor survival and short-lived therapeutic outcomes in diabetic patients.

Tafazzin deficiency in mouse mesenchymal stem cells promote reprogramming of activated B lymphocytes toward immunosuppressive phenotypes.

Barth Syndrome (BTHS) is a rare X-linked genetic disorder caused by mutation in the TAFAZZIN gene. Tafazzin (Taz) deficiency in BTHS patients results in an increased risk of infections. Mesenchymal stem cells (MSCs) are well known for their immune-inhibitory function. We examined how Taz-deficiency in murine MSCs impact their ability to modulate the function of lipopolysaccharide (LPS)-activated wild type (WT) B lymphocytes. MSCs from tafazzin knockdown (TazKD) mice exhibited a reduction in mitochondrial cardiolipin compared to wild type (WT) MSCs. However, mitochondrial bioenergetics and membrane potential were unaltered. In contrast, TazKD MSCs exhibited increased reactive oxygen species generation and increased glycolysis. The increased glycolysis was associated with an 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 compared to controls. Inhibition of glycolysis with 2-deoxyglucose attenuated the TazKD-mediated increased expression of cytotoxic T-lymphocyte-associated protein 4 and interleukin-10. When co-cultured with LPS-activated WT B cells, TazKD MSCs inhibited B cell proliferation and growth rate and reduced B cell secretion of immunoglobulin M compared to controls. In addition, co-culture of LPS-activated WT B cells with TazKD MSCs promoted B cell differentiation toward interleukin-10 secreting plasma cells and B regulatory cells compared to controls. The results indicate that Taz deficiency in MSCs promote reprogramming of activated B lymphocytes toward immunosuppressive phenotypes.

The toxic profile of tramadol combined with nicotine on the liver and testicles: evidence from endoplasmic reticulum stress.

BACKGROUND: Tramadol is one of the most commonly abused substances in the Middle East. Furthermore, smoking is extremely common among the population. METHODS: An experimental study was performed on Sprague-Dawley rats to explore the effects of both nicotine and tramadol on the liver and testes. The tramadol was administered at 10 and 20 mg/kg, respectively, while the nicotine was administered at 125 mg/kg. Histological examination and androgen receptor ELISA assay showed mild effects on the liver and proofed safety on the testis. Western blot analysis of BIP (immunoglobulin heavy-chain binding protein) and CHOP (CCAAT-enhancer-binding protein homologous protein) revealed that fewer problems were induced by adding nicotine to tramadol. Autophagy marker LCIII and apoptosis marker caspase-8 showed similar effects to CHOP and BIP on liver samples. The real-time PCR of BIP expression showed similar but not identical results. CONCLUSIONS: The results showed mild endoplasmic reticulum stress, autophagy, and apoptosis in the liver samples. Histological examination revealed stable spermatogenesis with average androgen receptor blood levels in the different groups.

Tafazzin deficiency attenuates anti-cluster of differentiation 40 and interleukin-4 activation of mouse B lymphocytes.

Barth syndrome (BTHS) is a rare X-linked genetic disease caused by mutations in TAFAZZIN. The tafazzin (Taz) protein is a cardiolipin remodeling enzyme required for maintaining mitochondrial function. Patients with BTHS exhibit impaired mitochondrial respiratory chain and metabolic function and are susceptible to serious infections. B lymphocytes (B cells) play a vital role in humoral immunity required to eradicate circulating antigens from pathogens. Intact mitochondrial respiration is required for proper B-cell function. We investigated whether Taz deficiency in mouse B cells altered their response to activation by anti-cluster of differentiation 40 (anti-CD40) + interleukin-4 (IL-4). B cells were isolated from 3-4-month-old wild type (WT) or tafazzin knockdown (TazKD) mice and were stimulated with anti-CD40 + IL-4 for 24 h and cellular bioenergetics, surface marker expression, proliferation, antibody production, and proteasome and immunoproteasome activities determined. TazKD B cells exhibited reduced mRNA expression of Taz, lowered levels of cardiolipin, and impairment in both oxidative phosphorylation and glycolysis compared to WT B cells. In addition, anti-CD40 + IL-4 stimulated TazKD B cells expressed lower levels of the immunogenic surface markers, cluster of differentiation 86 (CD86) and cluster of differentiation 69 (CD69), exhibited a lower proliferation rate, reduced production of immunoglobulin M and immunoglobulin G, and reduced proteasome and immunoproteasome proteolytic activities compared to WT B cells stimulated with anti-CD40 + IL-4. The results indicate that Taz is required to support T-cell-dependent signaling activation of mouse B cells.

Tafazzin deficiency impairs mitochondrial metabolism and function of lipopolysaccharide activated B lymphocytes in mice.

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.

Hypoxia disturbs the Migration and Adhesion characteristics of Mesenchymal Stem Cells.

Mesenchymal stem cells (MSCs) have been successfully used in treating many diseases which being verified by many preclinical and clinical trials.  Despite the exciting therapeutic potential of MSCs, multiple challenges encountered which hinder researchers from achieving successful clinical translations. Many studies have showed that moderate hypoxia (1-7% O2) considered as an important regulator of MSCs homing, migration, and differentiation. Additionally, low oxygen tension levels have been implicated in the maintenance of MSCs quiescence and plasticity in general. On the other hand, severe hypoxia (<1% O2) negatively affects the in vitro therapeutic potential of MSCs and causing their poor survival. Using Elisa assay we assessed some major adhesion markers that are known to be secreted by MSCs and play a role in cell-cell and cell-matrix adhesion under normoxia (21% O2) and severe hypoxia (0.5% O2). These markers including: SDF1-α, CXCR4, FAK, VEGF and ICAM-1. The results showed a significant drop in the adhesion markers in MSCs under severe hypoxia in comparing to normoxia, which causes a disruption in the cell-cell adhesion abilities of MSCs and ultimately can affect the incorporation of MSCs at the host site. These Findings can open new avenue to improve the attachment of MSCs at the transplantation site by targeting the adhesion and chemokines markers.

Hypoxia-induced downregulation of cyclooxygenase 2 leads to the loss of immunoprivilege of allogeneic mesenchymal stem cells.

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.

Hypoxia-induced increase in Sug1 leads to poor post-transplantation survival of allogeneic mesenchymal stem cells.

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.

Reduced Granule Cell Proliferation and Molecular Dysregulation in the Cerebellum of Lysosomal Acid Phosphatase 2 (ACP2) Mutant Mice.

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.

Inflammation in myocardial injury: mesenchymal stem cells as potential immunomodulators.

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.

Addressing the impact of different fetal bovine serum percentages on mesenchymal stem cells biological performance.

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.

High throughput screening reveals no significant changes in protein synthesis, processing, and degradation machinery during passaging of mesenchymal stem cells 1.

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.

Effects of high glucose and severe hypoxia on the biological behavior of mesenchymal stem cells at various passages.

BACKGROUND: Mesenchymal stem cells (MSCs) have been extensively studied for therapeutic potential, due to their regenerative and immunomodulatory properties. Serial passage and stress factors may affect the biological characteristics of MSCs, but the details of these effects have not been recognized yet. AIM: To investigate the effects of stress factors (high glucose and severe hypoxia) on the biological characteristics of MSCs at different passages, in order to optimize the therapeutic applications of MSCs. METHODS: In this study, we investigated the impact of two stress conditions; severe hypoxia and high glucose on human adipose-tissue derived MSCs (hAD-MSCs) at passages 6 (P6), P8, and P10. Proliferation, senescence and apoptosis were evaluated measuring WST-1, senescence-associated beta-galactosidase, and annexin V, respectively. RESULTS: Cells at P6 showed decreased proliferation and increased apoptosis under conditions of high glucose and hypoxia compared to control, while the extent of senescence did not change significantly under stress conditions. At P8 hAD-MSCs cultured in stress conditions had a significant decrease in proliferation and apoptosis and a significant increase in senescence compared to counterpart cells at P6. Cells cultured in high glucose at P10 had lower proliferation and higher senescence than their counterparts in the previous passage, while no change in apoptosis was observed. On the other hand, MSCs cultured under hypoxia showed decreased senescence, increased apoptosis and no significant change in proliferation when compared to the same conditions at P8. CONCLUSION: These results indicate that stress factors had distinct effects on the biological processes of MSCs at different passages, and suggest that senescence may be a protective mechanism for MSCs to survive under stress conditions at higher passage numbers.

The synthetic cannabinoids menace: a review of health risks and toxicity.

Synthetic cannabinoids (SCs) are chemically classified as psychoactive substances that target the endocannabinoid system in many body organs. SCs can initiate pathophysiological changes in many tissues which can be severe enough to damage the normal functionality of our body systems. The majority of SCs-related side effects are mediated by activating Cannabinoid Receptor 1 (CB1R) and Cannabinoid Receptor 2 (CB2R). The activation of these receptors can enkindle many downstream signalling pathways, including oxidative stress, inflammation, and apoptosis that ultimately can produce deleterious changes in many organs. Besides activating the cannabinoid receptors, SCs can act on non-cannabinoid targets, such as the orphan G protein receptors GPR55 and GPR18, the Peroxisome Proliferator-activated Receptors (PPARs), and the Transient receptor potential vanilloid 1 (TRPV1), which are broadly expressed in the brain and the heart and their activation mediates many pharmacological effects of SCs. In this review, we shed light on the multisystem complications found in SCs abusers, particularly discussing their neurologic, cardiovascular, renal, and hepatic effects, as well as highlighting the mechanisms that intermediate SCs-related pharmacological and toxicological consequences to provide comprehensive understanding of their short and long-term systemic effects.

The potential protective role of vitamin D and calcium supplements in reducing cardiovascular disease risk among elderly patients with osteopenia.

BACKGROUND: Cardiovascular disease and low bone mineral density are major health problems in the elderly. These two conditions are considered independent of each other and age-related diseases. The aim of this study is to investigate the association between low bone mineral density (BMD) and cardiovascular disease (CVD) incidents, and the effect of vitamin D and calcium supplement on the incidence of CVD in patients with low BMD. METHODS: A total of 1047 patients (597 females/450 males) with the age of 65 years and more were diagnosed with osteopenia for 13 years or more. The study also included 220 patients (107 females/113 males) with osteopenia who already took calcium and vitamin D continually since their diagnosis. BMD was measured by dual-energy X-ray absorptiometry. The incidence of any cardiovascular diseases in the study patients and the presence of corresponding risk factors were collected and analyzed. RESULTS: In both elderly Arab females and males, there was an association between total hip and femoral neck BMD and the possibility to have CVD. On the other hand, the results showed that patients who use calcium and vitamin D supplements showed a significant reduction in the incidence of CVD comparing to the non-treated patients. CONCLUSION: Low total hip and femoral neck BMD were associated with a higher chance to have CVD incidents in both elderly Arab males and females; moreover, calcium and vitamin D supplements have a possible protective role in reducing cardiovascular disease in elderly patients with osteopenia.

Delineating the molecular mechanisms of hippocampal neurotoxicity induced by chronic administration of synthetic cannabinoid AB-FUBINACA in mice.

Chronic use of synthetic cannabinoids (SCs) has been associated with cognitive and behavioural deficits and an increased risk of neuropsychiatric disorders. The underlying molecular and cellular mechanisms of the neurotoxic effects of long-term use of SCs have not been well investigated in the literature. Herein, we evaluated the in vivo effects of chronic administration of AB-FUBINACA on the hippocampus in mice. Our results revealed that the administration of AB-FUBINACA induced a significant impairment in recognition memory associated with histopathological changes in the hippocampus. These findings were found to be correlated with increased level of oxidative stress, neuroinflammation, and apoptosis markers, and reduced expression of brain-derived neurotrophic factor (BDNF), which plays an essential role in modulating synaptic plasticity integral for promoting learning and memory in the hippocampus. Additionally, we showed that AB-FUBINACA significantly decreased the expression of NR1, an important functional subunit of glutamate/NMDA receptors and closely implicated in the development of toxic psychosis. These findings shed light on the long-term neurotoxic effects of SCs on hippocampus and the underlying mechanisms of these effects. This study provided new targets for possible medical interventions to improve the treatment guidelines for SCs addiction.

The impact of chronic fentanyl administration on the cerebral cortex in mice: Molecular and histological effects.

PURPOSE: Fentanyl, a fully synthetic opioid, is widely used for severe pain management and has a huge abuse potential for its psychostimulant effects. Unlike other opioids, the neurotoxic effects of chronic fentanyl administration are still unclear. In particular, little is known about its effect on the cerebral cortex. The current study aims to test the chronic toxicity of fentanyl in the mice model. METHODS: Adult male Balb/c mice were chronically treated with low (0.05 mg/kg, i.p) and high (0.1 mg/kg, i.p) doses of fentanyl for 5 consecutive weeks, and various neurotoxic parameters, including apoptosis, oxidative stress, and neuroinflammatory response were assessed in the cortex. Potential histological as well as neurochemical changes were also evaluated. RESULTS: The results of this study show that chronic fentanyl administration induced intense levels of apoptosis, oxidative stress, and neuroinflammation in the cerebral cortex. These findings were found to be correlated with histopathological characteristics of neural degeneration and white matter injury. Moreover, fentanyl administration was found to reduce the expression of both NMDA receptor subunits and dopamine receptors and elevate the level of epidermal growth factor (EGF). CONCLUSION: Fentanyl administration induced neurotoxic effects in the mouse cerebral cortex that could be primarily mediated by the evoked oxidative-inflammatory response. The altered expression of NMDA receptors, dopamine receptors, and EGF suggests the pernicious effects of fentanyl addiction that may end in the development of toxic psychosis.

Mechanisms of analgesic effect of mesenchymal stem cells in osteoarthritis pain.

Osteoarthritis (OA) is the most common musculoskeletal disease, and it is a major cause of pain, disability and health burden. Pain is the most common and bothersome presentation of OA, but its treatment is still suboptimal, due to the short-term action of employed analgesics and their poor adverse effect profile. Due to their regenerative and anti-inflammatory properties, mesenchymal stem cells (MSCs) have been extensively investigated as a potential therapy for OA, and numerous preclinical and clinical studies found a significant improvement in joint pathology and function, pain scores and/or quality of life after administration of MSCs. Only a limited number of studies, however, addressed pain control as the primary end-point or investigated the potential mechanisms of analgesia induced by MSCs. In this paper, we review the evidence reported in literature that support the analgesic action of MSCs in OA, and we summarize the potential mechanisms of these antinociceptive effects.