Nanowired Delivery of Growth Hormone Attenuates Pathophysiology of Spinal Cord Injury and Enhances Insulin-Like Growth Factor-1 Concentration in the Plasma and the Spinal Cord

Spinal cord injury induced exacerbation of Alzheimer's disease like pathophysiology is reduced by topical application of nanowired cerebrolysin with monoclonal antibodies to amyloid beta peptide, p-tau and tumor necrosis factor alpha

Hallmark of Alzheimer's disease include amyloid beta peptide and phosphorylated tau deposition in brain that could be aggravated following traumatic of concussive head injury. However, amyloid beta peptide or p-tau in spinal cord following injury is not well known. In this investigation we measured amyloid beta peptide and p-tau together with tumor necrosis factor-alpha (TNF-α) in spinal cord and brain following 48 h after spinal cord injury in relation to the blood-spinal cord and blood-brain barrier, edema formation, blood flow changes and cell injury in perifocal regions of the spinal cord and brain areas. A focal spinal cord injury was inflicted over the right dorsal horn of the T10-11 segment (4 mm long and 2 mm deep) and amyloid beta peptide and p-tau was measured in perifocal rostral (T9) and caudal (T12) spinal cord segments as well as in the brain areas. Our observations showed a significant increase in amyloid beta peptide in the T9 and T12 segments as well as in remote areas of brain and spinal cord after 24 and 48 h injury. This is associated with breakdown of the blood-spinal cord (BSCB) and brain barriers (BBB), edema formation, reduction in blood flow and cell injury. After 48 h of spinal cord injury elevation of amyloid beta peptide, phosphorylated tau (p-tau) and tumor necrosis factor-alpha (TNF-α) was seen in T9 and T12 segments of spinal cord in cerebral cortex, hippocampus and brain stem regions associated with microglial activation as seen by upregulation of Iba1 and CD86. Repeated nanowired delivery of cerebrolysin topically over the traumatized segment repeatedly together with monoclonal antibodies (mAb) to amyloid beta peptide (AβP), p-tau and TNF-α significantly attenuated amyloid beta peptide, p-tau deposition and reduces Iba1, CD68 and TNF-α levels in the brain and spinal cord along with blockade of BBB and BSCB, reduction in blood flow, edema formation and cell injury. These observations are the first to show that spinal cord injury induces Alzheimer's disease like symptoms in the CNS, not reported earlier.

Sleep deprivation enhances amyloid beta peptide, p-tau and serotonin in the brain: Neuroprotective effects of nanowired delivery of cerebrolysin with monoclonal antibodies to amyloid beta peptide, p-tau and serotonin

Sleep deprivation is quite frequent in military during combat, intelligence gathering or peacekeeping operations. Even one night of sleep deprivation leads to accumulation of amyloid beta peptide burden that would lead to precipitation of Alzheimer's disease over the years. Thus, efforts are needed to slow down or neutralize accumulation of amyloid beta peptide (AβP) and associated Alzheimer's disease brain pathology including phosphorylated tau (p-tau) within the brain fluid environment. Sleep deprivation also alters serotonin (5-hydroxytryptamine) metabolism in the brain microenvironment and impair upregulation of several neurotrophic factors. Thus, blockade or neutralization of AβP, p-tau and serotonin in sleep deprivation may attenuate brain pathology. In this investigation this hypothesis is examined using nanodelivery of cerebrolysin- a balanced composition of several neurotrophic factors and active peptide fragments together with monoclonal antibodies against AβP, p-tau and serotonin (5-hydroxytryptamine, 5-HT). Our observations suggest that sleep deprivation induced pathophysiology is significantly reduced following nanodelivery of cerebrolysin together with monoclonal antibodies to AβP, p-tau and 5-HT, not reported earlier.

Co-Administration of Nanowired Monoclonal Antibodies to Inducible Nitric Oxide Synthase and Tumor Necrosis Factor Alpha Together with Antioxidant H-290/51 Reduces SiO2 Nanoparticles-Induced Exacerbation of Pathophysiology of Spinal Cord Trauma

Military personnel are often exposed to silica dust during combat operations across the globe. Exposure to silica dust in US military or service personnel could cause Desert Strom Pneumonitis also referred to as Al Eskan disease causing several organs damage and precipitate autoimmune dysfunction. However, the effects of microfine particles of sand inhalation-induced brain damage on the pathophysiology of traumatic brain or spinal cord injury are not explored. Previously intoxication of silica nanoparticles (50-60 nm size) is shown to exacerbates spinal cord injury induces blood-spinal cord barrier breakdown, edema formation and cellular changes. However, the mechanism of silica nanoparticles-induced cord pathology is still not well known. Spinal cord injury is well known to alter serotonin (5-hydroxytryptamine) metabolism and induce oxidative stress including upregulation of nitric oxide synthase and tumor necrosis factor alpha. This suggests that these agents are involved in the pathophysiology of spinal cord injury. In this review, we examined the effects of combined nanowired delivery of monoclonal antibodies to neuronal nitric oxide synthase (nNOS) together with tumor necrosis factor alpha (TNF-α) antibodies and a potent antioxidant H-290/51 to induce neuroprotection in spinal cord injury associated with silica nanoparticles intoxication. Our results for the first time show that co-administration of nanowired delivery of antibodies to nNOS and TNF-α with H-290/51 significantly attenuated silica nanoparticles-induced exacerbation of spinal cord pathology, not reported earlier.

The multiple roles of GH in neural ageing and injury

Advanced age is typically associated with a decrease in cognitive function including impairment in the formation and retention of new memories. The hippocampus is critical for learning and memory, especially spatial learning, and is particularly affected by ageing. With advanced age, multiple neural components can be detrimentally affected including a reduction in the number of neural stem and precursor cells, a decrease in the formation of adult born neurons (neurogenesis), and deficits in neural circuitry, all of which ultimately contribute to impaired cognitive function. Importantly, physical exercise has been shown to ameliorate many of these impairments and is able to improve learning and memory. Relevantly, growth hormone (GH) is an important protein hormone that decreases with ageing and increases following physical exercise. Originally described due to its role in longitudinal growth, GH has now been identified to play several additional key roles, especially in relation to the brain. Indeed, the regular decrease in GH levels following puberty is one of the most well documented components of neuroendocrine ageing. Growth hormone deficiency (GHD) has been described to have adverse effects on brain function, which can be ameliorated via GH replacement therapy. Physical exercise has been shown to increase circulating GH levels. Furthermore, we recently demonstrated the increase in exercise-mediated GH is critical for improved cognitive function in the aged mouse. Here we examine the multiple roles that GH plays, particularly in the aged brain and following trauma, irradiation and stroke, and how increasing GH levels can ameliorate deficits in cognition.

Human Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Attenuate Blood-Spinal Cord Barrier Disruption via the TIMP2/MMP Pathway After Acute Spinal Cord Injury

After spinal cord injury (SCI), destruction of the blood-spinal cord barrier (BSCB) results in infiltration of blood cells, such as neutrophils and macrophages, leading to permanent neurological dysfunction. Previous studies have shown that human bone marrow mesenchymal stem cell (BMSC)-derived exosomes have a beneficial neuroprotective effect in SCI models. However, whether BMSC-Exos contribute to the integrity of the BSCB has not been clarified. The purpose of this study was to investigate the mechanism of BMSC-Exo-induced changes in the permeability of the BSCB after SCI. Here, we first used BMSC-Exos to treat an SCI rat model, showing that BMSC-Exos can inhibit BSCB permeability damage and improve spontaneous repair. Next, we found that tissue inhibitors of matrix metalloproteinase 2 (TIMP2) have been shown to play an important role in the function of BMSC-Exos by inhibiting the matrix metalloproteinase (MMP) pathway, thereby reducing the reduction of cell junction proteins. Therefore, we constructed siTIMP2 to knock out TIMP2 in BMSC-Exos, which caused the activity of BMSC-Exos to be significantly weakened. Finally, we constructed an in vitro model of BSCB with HBMECs and verified that TIMP2 in BMSC-Exos in vitro can also alleviate BSCB damage. This proof-of-principle study demonstrates that BMSC-Exos can preserve the integrity of the BSCB and improve functional recovery after SCI through the TIMP2/MMP signaling pathway.

Future Perspectives in Spinal Cord Repair: Brain as Saviour? TSCI with Concurrent TBI: Pathophysiological Interaction and Impact on MSC Treatment

Traumatic spinal cord injury (TSCI), commonly caused by high energy trauma in young active patients, is frequently accompanied by traumatic brain injury (TBI). Although combined trauma results in inferior clinical outcomes and a higher mortality rate, the understanding of the pathophysiological interaction of co-occurring TSCI and TBI remains limited. This review provides a detailed overview of the local and systemic alterations due to TSCI and TBI, which severely affect the autonomic and sensory nervous system, immune response, the blood-brain and spinal cord barrier, local perfusion, endocrine homeostasis, posttraumatic metabolism, and circadian rhythm. Because currently developed mesenchymal stem cell (MSC)-based therapeutic strategies for TSCI provide only mild benefit, this review raises awareness of the impact of TSCI-TBI interaction on TSCI pathophysiology and MSC treatment. Therefore, we propose that unravelling the underlying pathophysiology of TSCI with concomitant TBI will reveal promising pharmacological targets and therapeutic strategies for regenerative therapies, further improving MSC therapy.

Insulin-like growth factor 1 promotes neurological functional recovery after spinal cord injury through inhibition of autophagy via the PI3K/Akt/mTOR signaling pathway

Spinal cord injury (SCI) is a serious trauma; however, the mechanisms underlying the role of insulin-like growth factor 1 (IGF-1) in autophagy following SCI remain to be elucidated. The present study aimed to investigate the therapeutic effect of IGF-1 on SCI and to determine whether IGF-1 regulates autophagy via the PI3K/Akt/mTOR signaling pathway. SH-SY5Y neuroblastoma cells were assigned to the H₂O₂, IGF-1 and control groups to investigate subsequent neuron injury in vitro. An MTT assay was performed to evaluate cell survival. In addition, Sprague-Dawley rats were randomly assigned to SCI, SCI + IGF-1 and sham groups, and Basso-Beatlie-Bresnahan scores were assessed to determine rat neurological function. Western blotting was used to analyze the autophagy level and the activation of the PI3K/Akt/mTOR signaling pathway. Cell survival was increased significantly in the IGF-1 group compared with the control group in vitro (P<0.05). Furthermore, neurological function was improved in the SCI + IGF-1 group compared with the control group in vivo (P<0.05). The western blotting results further demonstrated that LC3II/LC3I expression was increased in the IGF-1 group compared with the sham group in vivo and compared with the control group in vitro (both P<0.05). In the SCI + IGF-1 group, the expression levels of PI3K, phosphorylated (p)-Akt and p-mTOR were higher compared with those in the sham and SCI groups in vivo (P<0.05). Moreover, in the IGF-1 group, the expression levels of p-Akt and p-mTOR were higher compared with the control and the H₂O₂ groups in vitro (P<0.05). Collectively, the results of the present study suggested that IGF-1 promoted functional recovery in rats following SCI through neuroprotective effects. Furthermore, the underlying mechanism may involve activation of the PI3K/Akt/mTOR signaling pathway, followed by inhibition of autophagy. However, further investigation into the association between IGF-1-regulated autophagy and the activation of different subtypes of PI3K is required.

Therapeutic targets and nanomaterial-based therapies for mitigation of secondary injury after spinal cord injury

Spinal cord injury (SCI) and the resulting neurological trauma commonly result in complete or incomplete neurological dysfunction and there are few effective treatments for primary SCI. However, the following secondary SCI, including the changes of microvasculature, inflammatory response and oxidative stress around the injury site, may provide promising therapeutic targets. The advances of nanomaterials hold promise for delivering therapeutics to alleviate secondary SCI and promote functional recovery. In this review, we highlight recent achievements of nanomaterial-based therapy, specifically targeting blood-spinal cord barrier disruption, mitigation of the inflammatory response and lightening of oxidative stress after spinal cord injury.

Neuroprotective effects of insulin like growth factor-1 on engineered metal nanoparticles Ag, Cu and Al induced blood-brain barrier breakdown, edema formation, oxidative stress, upregulation of neuronal nitric oxide synthase and brain pathology

Military personnel are vulnerable to environmental or industrial exposure of engineered nanoparticles (NPs) from metals. Long-term exposure of NPs from various sources affect sensory-motor or cognitive brain functions. Thus, a possibility exists that chronic exposure of NPs affect blood-brain barrier (BBB) breakdown and brain pathology by inducing oxidative stress and/or nitric oxide production. This hypothesis was examined in the rat intoxicated with Ag, Cu or Al (50-60nm) nanoparticles (50mg/kg, i.p. once daily) for 7 days. In these NPs treated rats the BBB permeability, brain edema, neuronal nitric oxide synthase (nNOS) immunoreactivity and brain oxidants levels, e.g., myeloperoxidase (MP), malondialdehyde (MD) and glutathione (GT) was examined on the 8th day. Cu and Ag but not Al nanoparticles increased the MP and MD levels by twofold in the brain although, GT showed 50% decline. At this time increase in brain water content and BBB breakdown to protein tracers were seen in areas exhibiting nNOS positive neurons and cell injuries. Pretreatment with insulin like growth factor-1 (IGF-1) in high doses (1μg/kg, i.v. but not 0.5μg/kg daily for 7 days) together with NPs significantly reduced the oxidative stress, nNOS upregulation, BBB breakdown, edema formation and cell injuries. These novel observations demonstrate that (i) NPs depending on their metal constituent (Cu, Ag but not Al) induce oxidative stress and nNOS expression leading to BBB disruption, brain edema and cell damage, and (ii) IGF-1 depending on doses exerts powerful neuroprotection against nanoneurotoxicity, not reported earlier.

Phase II/III placebo-controlled randomized trial of safety and efficacy of growth hormone treatment in incomplete chronic traumatic spinal cord injury

STUDY DESIGN

This is a double blind phase II/III placebo-controlled randomized trial of the safety and efficacy of GH treatment in incomplete chronic traumatic spinal cord injury.

OBJECTIVE

The aim of this study was to investigate the possibility to use exogenous GH administration for motor recovery in chronic traumatic incomplete human SCI. The objectives were to establish safety and efficacy of a combined treatment of subcutaneous GH (or placebo) and rehabilitation in this population.

SETTING

Hospital Nacional de Parapléjicos METHODS: The pharmacological treatment was a subcutaneous daily dose of growth hormone (GH, Genotonorm 0.4 mg, Pfizer Pharmaceuticals) or placebo for one year. The pharmacological treatment was performed, during the first six months under hospitalization and supervised rehabilitation.

RESULTS

The main findings were that the combined treatment of GH plus rehabilitation treatment is feasible and safe, and that GH but not placebo increases the ISNCSCI motor score. On the other hand, the motor-score increment was marginal (after one-year combined treatment, the mean increment of the motor-score was around 2.5 points). Moreover, we found that intensive and long-lasting rehabilitation program per se increases the functional outcome of SCI individuals (measured using SCIM III and WISCI II).

CONCLUSIONS

It is important to highlight that our aim was to propose GH as a possible treatment to improve motor functions in incomplete SCI individuals. At least with the doses we used, we think that the therapeutic effects of this approach are not clinically relevant in most subjects with SCI.

Initiation of PI3K/AKT pathway by IGF-1 decreases spinal cord injury-induced endothelial apoptosis and microvascular damage

AIM

Apoptosis of endothelial cells (ECs) is a crucial factor in blood-spinal cord barrier (BSCB) disruption post spinal cord injury (SCI). Insulin-like growth factor-1 (IGF-1) is a protective cytokine that plays an important role in multiple diseases, whereas the distinct role in SCI-induced remains critical questions to address. Here we designed to explore the role and underlying mechanism of IGF-1 in endothelial damage after SCI.

MAIN METHODS

In the current study, we established mouse microvascular endothelial cells (MVECs) injury model via LPS and cDNA of IGF-1 was transfected into MVECs. In vivo SCI mice, overexpression of IGF-1 (SCI-IGF-1) and its corresponding empty vehicle (SCI-NC) were conducted using lentivirus, then apoptosis degree, component of tight junction, and inflammatory damage were evaluated.

KEY FINDINGS

IGF-1 treatment in MVECs displayed a milder apoptosis and cell damage under LPS insult. IGF-1 increased the level of PI3K/AKT pathway, which impeded the procedure of apoptosis. Blocking of PI3K/AKT pathway markedly neutralized the effect of IGF-1 treatment. Transfection of excess IGF-1 into SCI mice significantly corrected microenvironment of neural tissue repair, reduced area of injured core and improved functional recovery with greater activation of PI3K/AKT pathway.

SIGNIFICANCE

The results above argue that the promising roles played by IGF-1 is potentially vital for developing effective future therapies in SCI.

Growth hormone (GH) and synaptogenesis

Growth hormone (GH) is known to exert several roles during development and function of the nervous system. Initially, GH was exclusively considered a pituitary hormone that regulates body growth and metabolism, but now its alternative extrapituitary production and pleiotropic functions are widely accepted. Through excess and deficit models, the critical role of GH in nervous system development and adult brain function has been extensively demonstrated. Moreover, neurotrophic actions of GH in neural tissues include pro-survival effects, neuroprotection, axonal growth, synaptogenesis, neurogenesis and neuroregeneration. The positive effects of GH upon memory, behavior, mood, sensorimotor function and quality of life, clearly implicate a beneficial action in synaptic physiology. Experimental and clinical evidence about GH actions in synaptic function modulation, protection and restoration are revised in this chapter.

Protein Degradome of Spinal Cord Injury: Biomarkers and Potential Therapeutic Targets

Degradomics is a proteomics sub-discipline whose goal is to identify and characterize protease-substrate repertoires. With the aim of deciphering and characterizing key signature breakdown products, degradomics emerged to define encryptic biomarker neoproteins specific to certain disease processes. Remarkable improvements in structural and analytical experimental methodologies as evident in research investigating cellular behavior in neuroscience and cancer have allowed the identification of specific degradomes, increasing our knowledge about proteases and their regulators and substrates along with their implications in health and disease. A physiologic balance between protein synthesis and degradation is sought with the activation of proteolytic enzymes such as calpains, caspases, cathepsins, and matrix metalloproteinases. Proteolysis is essential for development, growth, and regeneration; however, inappropriate and uncontrolled activation of the proteolytic system renders the diseased tissue susceptible to further neurotoxic processes. In this article, we aim to review the protease-substrate repertoires as well as emerging therapeutic interventions in spinal cord injury at the degradomic level. Several protease substrates and their breakdown products, essential for the neuronal structural integrity and functional capacity, have been characterized in neurotrauma including cytoskeletal proteins, neuronal extracellular matrix glycoproteins, cell junction proteins, and ion channels. Therefore, targeting exaggerated protease activity provides a potentially effective therapeutic approach in the management of protease-mediated neurotoxicity in reducing the extent of damage secondary to spinal cord injury.

TiO2-Nanowired Delivery of DL-3-n-butylphthalide (DL-NBP) Attenuates Blood-Brain Barrier Disruption, Brain Edema Formation, and Neuronal Damages Following Concussive Head Injury

DL-3-n-butylphthalide (DL-NBP) is one of the constituents of Chinese celery extract that is used to treat stroke, dementia, and ischemic diseases. However, its role in traumatic brain injury is less well known. In this investigation, neuroprotective effects of DL-NBP in concussive head injury (CHI) on brain pathology were explored in a rat model. CHI was inflicted in anesthetized rats by dropping a weight of 114.6 g from a height of 20 cm through a guide tube on the exposed right parietal bone inducing an impact of 0.224 N and allowed them to survive 4 to 24 h after the primary insult. DL-NBP was administered (40 or 60 mg/kg, i.p.) 2 and 4 h after injury in 8-h survival group and 8 and 12 h after trauma in 24-h survival group. In addition, TiO₂-nanowired delivery of DL-NBP (20 or 40 mg/kg, i.p.) in 8 and 24 h CHI rats was also examined. Untreated CHI showed a progressive increase in blood-brain barrier (BBB) breakdown to Evans blue albumin (EBA) and radioiodine (^[131]-I), edema formation, and neuronal injuries. The magnitude and intensity of these pathological changes were most marked in the left hemisphere. Treatment with DL-NBP significantly reduced brain pathology in CHI following 8 to 12 h at 40-mg dose. However, 60-mg dose is needed to thwart brain pathology at 24 h following CHI. On the other hand, TiO₂-DL-NBP was effective in reducing brain damage up to 8 or 12 h using a 20-mg dose and only 40-mg dose was needed for neuroprotection in CHI at 24 h. These observations are the first to suggest that (i) DL-NBP is quite effective in reducing brain pathology and (ii) nanodelivery of DL-NBP has far more superior effects in CHI, not reported earlier.

GH deficiency in patients with spinal cord injury: efficacy/safety of GH replacement, a pilot study

Objective Growth hormone (GH) was shown to stimulate proliferation, migration and survival of neural cells in animal models. GH deficiency (GHD) was reported following traumatic brain lesions; however, there are not available data in spinal cord injury (SCI) patients. The aim of the study was to evaluate (1) the frequency of GHD in chronic SCI population; (2) the efficacy/safety of GH replacement in patients with SCI and suboptimal GH secretion. Design and methods Nineteen consecutive patients with chronic thoracic complete SCI (AIS-A) were studied. Patients with low GH secretion were randomized in a double-blind, placebo-controlled study to receive either subcutaneous placebo injections or GH combined with physical therapy, for 6 months. Baseline cranial MRI, AIS motor and sensory scale, quality of life (spinal cord impact measurement) and modified Ashworth spasticity scale, quantitative sensory testing and neurophysiological exploration were assessed at baseline, 1, 3 and 6 months following treatment. Results Thirteen had GH deficiency. Seven received GH, five placebo and one dropped out. Both groups were similar according to clinical and demographical data at baseline, except for greater GH deficiency in the GH treatment group. At 6th month, patients treated with GH showed a significant improvement in SCIM-III score and in electrical perception threshold up to the 5th level below SCI, on both sides compared to baseline. Conclusions GHD seems to be frequent in traumatic SCI and GH replacement is safe without side effects. GH combined with physical therapy can improve quality of life of SCI patients and, strikingly, the sensory perception below lesion level.

Novel multi-drug delivery hydrogel using scar-homing liposomes improves spinal cord injury repair

Proper selection and effective delivery of combination drugs targeting multiple pathophysiological pathways key to spinal cord injury (SCI) hold promise to address the thus far scarce clinical therapeutics for improving recovery after SCI. In this study, we aim to develop a clinically feasible way for targeted delivery of multiple drugs with different physiochemical properties to the SCI site, detail the underlying mechanism of neural recovery, and detect any synergistic effect related to combination therapy.

Methods: Liposomes (LIP) modified with a scar-targeted tetrapeptide (cysteine-alanine-glutamine-lysine, CAQK) were first constructed to simultaneously encapsulate docetaxel (DTX) and brain-derived neurotrophic factor (BDNF) and then were further added into a thermosensitive heparin-modified poloxamer hydrogel (HP) with affinity-bound acidic fibroblast growth factor (aFGF-HP) for local administration into the SCI site (CAQK-LIP-GFs/DTX@HP) in a rat model. In vivo fluorescence imaging was used to examine the specificity of CAQK-LIP-GFs/DTX binding to the injured site. Multiple comprehensive evaluations including biotin dextran amine anterograde tracing and magnetic resonance imaging were used to detect any synergistic effects and the underlying mechanisms of CAQK-LIP-GFs/DTX@HP both in vivo (rat SCI model) and in vitro (primary neuron).

Results: The multiple drugs were effectively delivered to the injured site. The combined application of GFs and DTX supported neuro-regeneration by improving neuronal survival and plasticity, rendering a more permissive extracellular matrix environment with improved regeneration potential. In addition, our combination therapy promoted axonal regeneration via moderation of microtubule function and mitochondrial transport along the regenerating axon.

Conclusion: This novel multifunctional therapeutic strategy with a scar-homing delivery system may offer promising translational prospects for the clinical treatment of SCI.

Growth Hormone (GH) and Gonadotropin-Releasing Hormone (GnRH) in the Central Nervous System: A Potential Neurological Combinatory Therapy?

This brief review of the neurological effects of growth hormone (GH) and gonadotropin-releasing hormone (GnRH) in the brain, particularly in the cerebral cortex, hypothalamus, hippocampus, cerebellum, spinal cord, neural retina, and brain tumors, summarizes recent information about their therapeutic potential as treatments for different neuropathologies and neurodegenerative processes. The effect of GH and GnRH (by independent administration) has been associated with beneficial impacts in patients with brain trauma and spinal cord injuries. Both GH and GnRH have demonstrated potent neurotrophic, neuroprotective, and neuroregenerative action. Positive behavioral and cognitive effects are also associated with GH and GnRH administration. Increasing evidence suggests the possibility of a multifactorial therapy that includes both GH and GnRH.

Epothilone B impairs functional recovery after spinal cord injury by increasing secretion of macrophage colony-stimulating factor

The microtubule-stabilizing drug epothilone B (epoB) has shown potential value in the treatment of spinal cord injury (SCI) through diverse mechanisms. However, it remains elusive why a limited overall effect was observed. We aim to investigate the limiting factors underlying functional recovery promoted by epoB. The same SCI model treated by epoB was established as discussed previously. We used a cerebrospinal fluid (CSF) sample to assess the changes in cytokines in milieu of the SCI lesion site after epoB treatment. We then analyzed the source of cytokines, the state of microglia/macrophages/monocytes (M/Ms), and the recruitment of neutrophil in the lesion site by using the results of antibody array. Following these findings, we further evaluated the motor functional recovery caused by the reshaped microenvironment. Systemic administration of epoB significantly increased levels of several cytokines in the CSF of the rat SCI model; macrophage colony-stimulating factor (M-CSF) secreted by intact central nervous system (CNS) cells was one of the cytokines with increased levels. Along with epoB and other cytokines, M-CSF reshapes the SCI milieu by activating the microglias, killing bone marrow-derived macrophages, polarizing the M/M to M1 phenotype, and activating downstream cytokines to exacerbate the SCI injury, but it also increases the expression of neurotrophic factors. Anti-inflammatory therapy using a neutralizing antibody mix shows encouraging results. Using in vivo experiments, our findings indicate that epoB inhibits the SCI functional recovery in many ways by reshaping the milieu, which counteracts the therapeutic efficacy that led to the limited overall effectiveness.

Growth Hormone (GH) and Rehabilitation Promoted Distal Innervation in a Child Affected by Caudal Regression Syndrome

Caudal regression syndrome (CRS) is a malformation occurring during the fetal period and mainly characterized by an incomplete development of the spinal cord (SC), which is often accompanied by other developmental anomalies. We studied a 9-month old child with CRS who presented interruption of the SC at the L2–L3 level, sacral agenesis, a lack of innervation of the inferior limbs (flaccid paraplegia), and neurogenic bladder and bowel. Given the known positive effects of growth hormone (GH) on neural stem cells (NSCs), we treated him with GH and rehabilitation, trying to induce recovery from the aforementioned sequelae. The Gross Motor Function Test (GMFM)-88 test score was 12.31%. After a blood analysis, GH treatment (0.3 mg/day, 5 days/week, during 3 months and then 15 days without GH) and rehabilitation commenced. This protocol was followed for 5 years, the last GH dose being 1 mg/day. Blood analysis and physical exams were performed every 3 months initially and then every 6 months. Six months after commencing the treatment the GMFM-88 score increased to 39.48%. Responses to sensitive stimuli appeared in most of the territories explored; 18 months later sensitive innervation was complete and the patient moved all muscles over the knees and controlled his sphincters. Three years later he began to walk with crutches, there was plantar flexion, and the GMFM-88 score was 78.48%. In summary, GH plus rehabilitation may be useful for innervating distal areas below the level of the incomplete spinal cord in CRS. It is likely that GH acted on the ependymal SC NSCs, as the hormone does in the neurogenic niches of the brain, and rehabilitation helped to achieve practically full functionality.

Epidermal growth factor attenuates blood-spinal cord barrier disruption via PI3K/Akt/Rac1 pathway after acute spinal cord injury

After spinal cord injury (SCI), disruption of blood–spinal cord barrier (BSCB) elicits blood cell infiltration such as neutrophils and macrophages, contributing to permanent neurological disability. Previous studies show that epidermal growth factor (EGF) produces potent neuroprotective effects in SCI models. However, little is known that whether EGF contributes to the integrity of BSCB. The present study is performed to explore the mechanism of BSCB permeability changes which are induced by EGF treatment after SCI in rats. In this study, we demonstrate that EGF administration inhibits the disruption of BSCB permeability and improves the locomotor activity in SCI model rats. Inhibition of the PI3K/Akt pathways by a specific inhibitor, LY294002, suppresses EGF‐induced Rac1 activation as well as tight junction (TJ) and adherens junction (AJ) expression. Furthermore, the protective effect of EGF on BSCB is related to the activation of Rac1 both in vivo and in vitro. Blockade of Rac1 activation with Rac1 siRNA downregulates EGF‐induced TJ and AJ proteins expression in endothelial cells. Taken together, our results indicate that EGF treatment preserves BSCB integrity and improves functional recovery after SCI via PI3K‐Akt‐Rac1 signalling pathway.