Treatment of rats with spinal cord injury using human bone marrow-derived stromal cells prepared by negative selection

Improved Efficacy of Delayed Treatment with Human Bone Marrow-Derived Stromal Cells Evaluated in Rats with Spinal Cord Injury

The treatment of spinal cord injury (SCI) with uncultivated human bone marrow-derived stromal cells (bmSCs) prepared by negative selection has been proposed to be therapeutically superior to treatment with stem cells that were expanded in vitro. To explore their use in clinical trials, we studied the functional effects of delayed application at 7 days after SCI by testing different doses of bmSCs. Spinal cord contusion injury was induced in adult male Wistar rats at the thoracic level T9. Human bmSCs were prepared by negative selection without expansion in vitro (NeuroCellsTM). Treatment consisted of one 150 µL injection into the cisterna magna containing 0.5 or 2.5 million fresh bmSCs or 2.5 million bmSCs. The recovery of motor functions was evaluated during a surveillance period of six weeks (6 W), during which spinal cords were assessed histologically. Treatment resulted in a significant, dose-dependent therapeutic effect on the recovery of motor performance. The histological analysis revealed a lower degree of axonal degeneration and better survival of neurons and oligodendrocytes in bmSCs treated rats. Our results support delayed intrathecal application of bmSCs prepared by negative selection without expansion in vitro as a treatment of SCI.

Krishnan L, Abelson KSP. Refinement of the motorised laminectomy-assisted rat spinal cord injury model by analgesic treatment

Usage and reporting of analgesia in animal models of spinal cord injury (SCI) have been sparse and requires proper attention. The majority of experimental SCI research uses rats as an animal model. This study aimed to probe into the effects of some commonly used regimens with NSAIDs and opioids on well-being of the rats as well as on the functional outcome of the model. This eight-week study used forty-two female Wistar rats (Crl: WI), randomly and equally divided into 6 treatment groups, viz. I) tramadol (5mg/kg) and buprenorphine (0.05mg/kg); II) carprofen (5mg/kg) and buprenorphine (0.05mg/kg); III) carprofen (5mg/kg); IV) meloxicam (1mg/kg) and buprenorphine (0.05mg/kg); V) meloxicam (1mg/kg); and VI) no analgesia (0.5 ml sterile saline). Buprenorphine was administered twice daily whereas other treatments were given once daily for five days post-operatively. Injections were given subcutaneously. All animals underwent dental burr-assisted laminectomy at the T10-T11 vertebra level. A custom-built calibrated spring-loaded 200 kilodynes force deliverer was used to induce severe SCI. Weekly body weight scores, Rat Grimace Scale (RGS), and dark-phase home cage activity were used as markers for well-being. Weekly Basso Beattie and Bresnahan (BBB) scores served as markers for functionality together with Novel Object Recognition test (NOR) at week 8 and terminal histopathology using area of vacuolisation and live neuronal count from the ventral horns of spinal cord. It was concluded that the usage of analgesia improved animal wellbeing while having no effects on the functional aspects of the animal model in comparison to the animals that received no analgesics.

Stem cells and pain

Pain can be defined as an unpleasant sensory and emotional experience caused by either actual or potential tissue damage or even resemble that unpleasant experience. For years, science has sought to find treatment alternatives, with minimal side effects, to relieve pain. However, the currently available pharmacological options on the market show significant adverse events. Therefore, the search for a safer and highly efficient analgesic treatment has become a priority. Stem cells (SCs) are non-specialized cells with a high capacity for replication, self-renewal, and a wide range of differentiation possibilities. In this review, we provide evidence that the immune and neuromodulatory properties of SCs can be a valuable tool in the search for ideal treatment strategies for different types of pain. With the advantage of multiple administration routes and dosages, therapies based on SCs for pain relief have demonstrated meaningful results with few downsides. Nonetheless, there are still more questions than answers when it comes to the mechanisms and pathways of pain targeted by SCs. Thus, this is an evolving field that merits further investigation towards the development of SC-based analgesic therapies, and this review will approach all of these aspects.

Stem Cell Therapy in Spinal Cord Injury-Induced Neurogenic Lower Urinary Tract Dysfunction

Spinal cord injury (SCI) is a devastating condition that enormously affects an individual's health and quality of life. Neurogenic lower urinary tract dysfunction (NLUTD) is one of the most important sequelae induced by SCI, causing complications including urinary tract infection, renal function deterioration, urinary incontinence, and voiding dysfunction. Current therapeutic methods for SCI-induced NLUTD mainly target on the urinary bladder, but the outcomes are still far from satisfactory. Stem cell therapy has gained increasing attention for years for its ability to rescue the injured spinal cord directly. Stem cell differentiation and their paracrine effects, including exosomes, are the proposed mechanisms to enhance the recovery from SCI. Several animal studies have demonstrated improvement in bladder function using mesenchymal stem cells (MSCs) and neural stem cells (NSCs). Human clinical trials also provide promising results in urodynamic parameters after MSC therapy. However, there is still uncertainty about the ideal treatment window and application protocol for stem cell therapy. Besides, data on the therapeutic effects regarding NSCs and stem cell-derived exosomes in SCI-related NLUTD are scarce. Therefore, there is a pressing need for further well-designed human clinical trials to translate the stem cell therapy into a formal therapeutic option for SCI-induced NLUTD.

Mechanisms and Treatments of Peripheral Nerve Injury

ABSTRACT

Peripheral nerve injury is a common injury disease. Understanding of the mechanisms of periphery nerve repair and regeneration after injury is an essential prerequisite for treating related diseases. Although the biological mechanisms of peripheral nerve injury and regeneration have been studied comprehensively, the clinical treatment methods are still limited. The bottlenecks of the treatments are the shortage of donor nerves and the limited surgical precision. Apart from the knowledge regarding the fundamental characteristics and physical processes of peripheral nerve injury, numerous studies have found that Schwann cells, growth factors, and extracellular matrix are main factors affecting the repair and regeneration process of injured nerves. At present, the therapeutical methods of the disease include microsurgery, autologous nerve transplantation, allograft nerve transplantation and tissue engineering technology. Tissue engineering technology, which combines seed cells, neurotrophic factors, and scaffold materials together, is promising for treating the patients with long-gapped and large nerve damage. With the development of neuron science and technology, the treatment of peripheral nerve injury diseases will continue being improved.

Tauroursodeoxycholic Acid Reduces Neuroinflammation but Does Not Support Long Term Functional Recovery of Rats with Spinal Cord Injury

The bile acid tauroursodeoxycholic acid (TUDCA) reduces cell death under oxidative stress and inflammation. Implants of bone marrow-derived stromal cells (bmSC) are currently under investigation in clinical trials of spinal cord injury (SCI). Since cell death of injected bmSC limits the efficacy of this treatment, the cytoprotective effect of TUDCA may enhance its benefit. We therefore studied the therapeutic effect of TUDCA and its use as a combinatorial treatment with human bmSC in a rat model of SCI. A spinal cord contusion injury was induced at thoracic level T9. Treatment consisted of i.p. injections of TUDCA alone or in combination with one injection of human bmSC into the cisterna magna. The recovery of motor functions was assessed during a surveillance period of six weeks. Biochemical and histological analysis of spinal cord tissue confirmed the anti-inflammatory activity of TUDCA. Treatment improved the recovery of autonomic bladder control and had a positive effect on motor functions in the subacute phase, however, benefits were only transient, such that no significant differences between vehicle and TUDCA-treated animals were observed 1–6 weeks after the lesion. Combinatorial treatment with TUDCA and bmSC failed to have an additional effect compared to treatment with bmSC only. Our data do not support the use of TUDCA as a treatment of SCI.

Thrombin acts as inducer of proinflammatory macrophage migration inhibitory factor in astrocytes following rat spinal cord injury

BACKGROUND

The danger-associated molecular patterns (DAMPs) are critical contributors to the progressive neuropathology and thereafter affect the functional outcomes following spinal cord injury (SCI). Up to now, the regulatory mechanisms on their inducible production from the living cells remain elusive, aside from their passive release from the necrotic cells. Thrombin is immediately activated by the damaged or stressed central nervous system (CNS), which potently mediates inflammatory astrocytic responses through proteolytic cleavage of protease-activated receptors (PARs). Therefore, SCI-activated thrombin is conceived to induce the production of DAMPs from astrocytes at lesion site.

METHODS

Rat SCI model was established by the cord contusion at T8-T10. The expression of thrombin and macrophage migration inhibitory factor (MIF) was determined by ELISA and Western blot. The PAR1, PAR3, and PAR4 receptors of thrombin were examined by PCR and immunohistochemistry. Primary astrocytes were isolated and purified from the spinal cord, followed by stimulation with different concentrations of thrombin either for transcriptome sequencing or for analysis of thrombin-mediated expression of MIF and related signal pathways in the presence or absence of various inhibitors. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale.

RESULTS

MIF protein levels were significantly elevated in parallel with those of thrombin induced by SCI. Immunostaining demonstrated that PAR1 receptor, together with MIF, was abundantly expressed in astrocytes. By transcriptome sequencing and bioinformatical analysis of thrombin-stimulated primary astrocytes, MIF was identified to be dynamically regulated by the serine protease. Investigation of the underlying mechanism using various inhibitors revealed that thrombin-activated PAR1 was responsible for the MIF production of astrocytes through modulation of JNK/NFκB pathway. Administration of PAR1 inhibitor at lesion sites following SCI significantly reduced the protein levels of MIF and ameliorated functional deficits of rat locomotion.

CONCLUSION

SCI-activated thrombin is a robust inducer of MIF production from astrocytes. Exploring the roles of thrombin in promoting the production of DAMPs from astrocytes at lesion site will provide an alternative strategy for the clinical therapy of CNS inflammation.

Stem cell treatment trials of spinal cord injuries in animals

BACKGROUND

Spinal cord injury (SCI) is a serious neurological spinal cord damage that resulted in the loss of temporary or permanent function. However, there are even now no effective therapies for it. So, a new medical promising therapeutic hotspot over the previous decades appeared which was (Stem cell (SC) cure of SCI). Otherwise, animal models are considered in preclinical research as a model for humans to trial a potential new treatment.

METHODOLOGY

Following articles were saved from different databases (PubMed, Google scholar, Egyptian knowledge bank, Elsevier, Medline, Embase, ProQuest, BMC) on the last two decades, and data were obtained then analyzed.

RESULTS

This review discusses the type and grading of SCI. As well as different types of stem cells therapy for SCI, including mesenchymal stem cells (MSCs), neural stem cells (NSCs), hematopoietic stem cells (HSCs), induced pluripotent stem cells (iPSCs), and embryonic stem cells (ESCs). The review focuses on the transplantation pathways, clinical evaluation, and clinical signs of different types of SC on different animal models which are summarized in tables to give an easy to reach.

CONCLUSION

Pharmacological and physiotherapy have limited regenerative power in comparison with stem cells medication in the treatment of SCI. Among several sources of cell therapies, mesenchymal stromal/stem cell (MSC) one is being progressively developed as a trusted important energetic way to repair and regenerate. Finally, a wide-ranged animal models have been condensed that helped in human clinical trial therapies.

Bile acids attenuate PKM2 pathway activation in proinflammatory microglia

Glycolysis is the metabolic pathway that converts glucose into pyruvate. Central nervous system (CNS) pathologies, such as spinal cord injury (SCI) and ischemia, are accompanied by an increase of the glycolytic pathway in the damaged areas as part of the inflammatory response. Pyruvate kinase is a key glycolytic enzyme that converts phosphoenolpyruvate and ADP to pyruvate and ATP. The protein has two isoforms, PKM1 and PKM2, originated from the same gene. As a homodimer, PKM2 loses the pyruvate kinase activity and acts as a transcription factor that regulates the expression of target genes involved in glycolysis and inflammation. After SCI, resident microglia and hematogenous macrophages are key inducers of the inflammatory response with deleterious effects. Activation of the bile acid receptor TGR5 inhibits the pro-inflammatory NFκB pathway in microglia and macrophages. In the present study we have investigated whether bile acids affect the expression of glycolytic enzymes and their regulation by PKM2. Bacterial lipopolysaccharide (LPS) induced the expression of PKM1, PKM2 and its target genes in primary cultures of microglial and Raw264.7 macrophage cells. SCI caused an increase of PKM2 immunoreactivity in macrophages after SCI. Pretreatment with tauroursodeoxycholic acid (TUDCA) or taurolithocholic acid (TLCA) reduced the expression of PKM2 and its target genes in cell cultures. Similarly, after SCI, TUDCA treatment reduced the expression of PKM2 in the lesion center. These results confirm the importance of PKM2 in the inflammatory response in CNS pathologies and indicate a new mechanism of bile acids as regulators of PKM2 pathway.

Enhancing Functional Recovery Through Intralesional Application of Extracellular Vesicles in a Rat Model of Traumatic Spinal Cord Injury

Local inflammation plays a pivotal role in the process of secondary damage after spinal cord injury. We recently reported that acute intravenous application of extracellular vesicles (EVs) secreted by human umbilical cord mesenchymal stromal cells dampens the induction of inflammatory processes following traumatic spinal cord injury. However, systemic application of EVs is associated with delayed delivery to the site of injury and the necessity for high doses to reach therapeutic levels locally. To resolve these two constraints, we injected EVs directly at the lesion site acutely after spinal cord injury. We report here that intralesional application of EVs resulted in a more robust improvement of motor recovery, assessed with the BBB score and sub-score, as compared to the intravenous delivery. Moreover, the intralesional application was more potent in reducing inflammation and scarring after spinal cord injury than intravenous administration. Hence, the development of EV-based therapy for spinal cord injury should aim at an early application of vesicles close to the lesion.

Extracellular vesicles derived from CD73 modified human umbilical cord mesenchymal stem cells ameliorate inflammation after spinal cord injury

BACKGROUND

Spinal cord injury (SCI) is an inflammatory condition, and excessive adenosine triphosphate (ATP) is released into the extracellular space, which can be catabolized into adenosine by CD73. Extracellular vesicles have been designed as nano drug carriers in many diseases. However, their impacts on delivery of CD73 after SCI are not yet known. We aimed to construct CD73 modified extracellular vesicles and explore the anti-inflammatory effects after SCI.

METHODS

CD73 engineered extracellular vesicles (CD73+ hucMSC-EVs) were firstly established, which were derived from human umbilical cord mesenchymal stem cells (hucMSCs) transduced by lentiviral vectors to upregulate the expression of CD73. Effects of CD73+ hucMSC-EVs on hydrolyzing ATP into adenosine were detected. The polarization of M2/M1 was verified by immunofluorescence. Furthermore, A2aR and A_2bR inhibitors and A2bR knockdown cells were used to investigate the activated adenosine receptor. Biomarkers of microglia and levels of cAMP/PKA were also detected. Repetitively in vivo study, morphology staining, flow cytometry, cytokine analysis, and ELISA assay, were also applied for verifications.

RESULTS

CD73+ hucMSC-EVs reduced concentration of ATP and promoted the level of adenosine. In vitro experiments, CD73+ hucMSC-EVs increased macrophages/microglia M2:M1 polarization, activated adenosine 2b receptor (A2bR), and then promoted cAMP/PKA signaling pathway. In mice using model of thoracic spinal cord contusion injury, CD73+ hucMSC-EVs improved the functional recovery after SCI through decreasing the content of ATP in cerebrospinal fluid and improving the polarization from M1 to M2 phenotype. Thus, the cascaded pro-inflammatory cytokines were downregulated, such as TNF-α, IL-1β, and IL-6, while the anti-inflammatory cytokines were upregulated, such as IL-10 and IL-4.

CONCLUSIONS

CD73+ hucMSC-EVs ameliorated inflammation after spinal cord injury by reducing extracellular ATP, promoting A2bR/cAMP/PKA pathway and M2/M1 polarization. CD73+ hucMSC-EVs might be promising nano drugs for clinical application in SCI therapy.

Exosomes secreted from sonic hedgehog-modified bone mesenchymal stem cells facilitate the repair of rat spinal cord injuries

BACKGROUND

Spinal cord injuries (SCIs) can cause a loss of neurons and associated sensory and motor functionality below the injured site. No approaches to treating SCIs in humans have been developed to date. Exosomes are extracellular vesicles that hold promise as a potential therapeutic modality when treating such injuries. The present study was thus designed to determine whether sonic hedgehog (Shh)-overexpressing bone mesenchymal stem cell (BMSC)-derived exosomes were protective in the context of SCIs.

METHODS

Exosomes were extracted from control or Shh lentivirus-transduced BMSCs, yielding respective BMSC-Exo and BMSC-Shh-Exo preparations which were intravenously injected into SCI model rats. Shh expression in spinal cord tissues in these animals was then assessed via immunohistochemical staining, while Basso-Beattie-Bresnahan (BBB) scores were utilized to measure high limb motor function. Neuronal damage and regeneration within the spinal cord were additionally evaluated via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), Nissl, hematoxylin and eosin, and immunofluorescent staining.

RESULTS

Both BMSC-Exo and BMSC-Shh-Exo preparations significantly increased Shh expression in the spinal cord of SCI model rats and improved BBB scores in these treated animals, while also increasing the frequencies of Nissl- and NeuN-positive neurons are reducing the numbers of apoptotic and GFAP-positive neurons. While both treatments yielded some degree of benefit to treated animals relative to untreated controls, BMSC-Shh-Exos were more beneficial than were control BMSC-Exos.

CONCLUSIONS

Shh-overexpressing BMSC-derived exosomes represent an effective treatment that can facilitate SCI repair in rats.

Spinal cord injury repair using mesenchymal stem cells derived from bone marrow in mice: A stereological study

Transplantation of bone marrow stem cells (BMSCs) has shown to have a vital role in promoting nerve regeneration after SCI. The aim of this study was to investigate the effect of BMSCs transplantation in healing of spinal cord injury (SCI) in mice based on morphologic parameters. Forty two male mice were randomly divided into 3 groups of control with no intervention, experimental SCI without treatment, and experimental SCI transplanted with 2 × 10⁵ BMSCs intravenously. To induce SCI bilaterally, T10 was compressed for 2 min. The animals were sacrificed 3 and 5 weeks after SCI and T7-T11 segments of spinal cord were removed and stained by Giemsa and H&E methods. Stereological assessment estimated the gray and white matter volume, the number of neurons and neuroglia and diameter of central canal. The average amount of gray matter in SCI injury group was significantly lower than control group. An increase in the number of neurons was noted after cell transplantation. The number of neurons in SCI injury group significantly decreased in comparison to the control group. In cell transplantation group, a significant increase in the number of neurons was visible when compared to SCI injury group. The increase in the number of neurons after cell transplantation denotes to the regenerative potential of BMSCs in SCI. These findings can be added to the literature and open a new window when targeting treatment of SCI.

Stem Cells in the Treatment of Neuropathic Pain: Research Progress of Mechanism

Neuropathic pain (NP) is pain caused by somatosensory nervous system injury or disease. Its prominent symptoms are spontaneous pain, hyperalgesia, and allodynia, and the sense of pain is extremely strong. Owing to the complex mechanism, conventional painkillers lack effectiveness. Recently, research on the treatment of NP by stem cells is increasing and promising results have been achieved in preclinical research. In this review, we briefly introduce the neuropathic pain, the current treatment strategy, and the development of stem cell therapy, and we collected the experimental and clinical trial articles of many kinds of stem cells in the treatment of neuropathic pain from the past ten years. We analyzed and summarized the general efficacy and mechanism of stem cells in the treatment of neuropathic pain. We found that the multiple-mechanism approach was different from the single mechanism of routine clinical drugs; stem cells play a role in peripheral mechanism, central mechanism, and disinhibition of spinal cord level that lead to neuropathic pain, so they are more effective in analgesia and treatment of neuropathic pain.

Why do anti-inflammatory signals of bone marrow-derived stromal cells improve neurodegenerative conditions where anti-inflammatory drugs fail?

Neurodegenerative disorders share the final degenerative pathway, the inflammation-induced apoptosis and/or necrosis, irrespective of their etiology, be it of acute and chronic traumatic, vascular and idiopathic origin. Although disease-modifying strategies are an unmet need in these disorders, lately, (pre)clinical studies suggested favorable effects after an intervention with bone marrow-derived stromal cells (bm-SC). Recent interventions with intrathecal transplantation of these cells in preclinical rodent models improved the functional outcome and reduced the inflammation, but not anti-inflammatory drugs. The benefit of bm-SCs was demonstrated in rats with an acute (traumatic spinal cord injury, tSCI) and in mice with a chronic [amyotrophic lateral sclerosis (ALS)-like FUS 1-358 or SOD1-G93-A mutation] neurodegenerative process. Bm-SCs, were found to modify underlying disease processes, to reduce final clinical SCI-related outcome, and to slow down ALS-like clinical progression. After double-blind interventions with bm-SC transplantations, Vehicle (placebo), and (non)steroidal anti-inflammatory drugs (Methylprednisolone, Riluzole, Celecoxib), clinical, histological and histochemical findings, serum/spinal cytokines, markers for spinal microglial activation inclusive, evidenced the cell-to-cell action of bm-SCs in both otherwise healthy and immune-deficient tSCI-rats, as well as wild-type and FUS/SOD1-transgenic ALS-like mice. The multi-pathway hypothesis of the cell-to-cell action of bmSCs, presumably using extracellular vesicles (EVs) as carriers of messages in the form of RNAs, DNA, proteins, and lipids rather than influencing a single inflammatory pathway, could be justified by the reported differences of cytokines and other chemokines in the serum and spinal tissue. The mode of action of bm-SCs is hypothesized to be associated with its dedicated adjustment of the pro-apoptotic glycogen synthase kinase-3β level towards an anti-apoptotic level whereas their multi-pathway hypothesis seems to be confirmed by the decreased levels of the pro-inflammatory interleukin (IL)-1β and tumor necrosis factor (TNF) as well as the level of the marker of activated microglia, ionized calcium binding adapter (Iba)-1 level.