Amelioration of Both Central and Peripheral Neuropathy in Mouse Models of Type 1 and Type 2 Diabetes by the Neurogenic Molecule NSI-189.

While peripheral neuropathy is the most common complication of long-term diabetes, cognitive deficits associated with encephalopathy and myelopathy also occur. Diabetes is a risk factor for Alzheimer disease (AD) and increases the risk of progression from mild cognitive impairment to AD. The only current recommendation for preventing or slowing the progression of peripheral neuropathy is to maintain close glycemic control, while there is no recommendation for central nervous system disorders.

Survival of syngeneic and allogeneic iPSC-derived neural precursors after spinal grafting in minipigs.

The use of autologous (or syngeneic) cells derived from induced pluripotent stem cells (iPSCs) holds great promise for future clinical use in a wide range of diseases and injuries. It is expected that cell replacement therapies using autologous cells would forego the need for immunosuppression, otherwise required in allogeneic transplantations. However, recent studies have shown the unexpected immune rejection of undifferentiated autologous mouse iPSCs after transplantation.

Remediation of Radiation-Induced Cognitive Dysfunction through Oral Administration of the Neuroprotective Compound NSI-189.

Clinical management of primary and secondary central nervous system (CNS) malignancies frequently includes radiotherapy to forestall tumor growth and recurrence after surgical resection. While cranial radiotherapy remains beneficial, adult and pediatric brain tumor survivors suffer from a wide range of debilitating and progressive cognitive deficits. Although this has been recognized as a significant problem for decades, there remains no clinical recourse for the unintended neurocognitive sequelae associated with these types of cancer treatments.

Amelioration of Penetrating Ballistic-Like Brain Injury Induced Cognitive Deficits after Neuronal Differentiation of Transplanted Human Neural Stem Cells.

Penetrating traumatic brain injury (PTBI) is one of the major cause of death and disability worldwide. Previous studies with penetrating ballistic-like brain injury (PBBI), a PTBI rat model revealed widespread perilesional neurodegeneration, similar to that seen in humans following gunshot wound to the head, which is unmitigated by any available therapies to date. Therefore, we evaluated human neural stem cell (hNSC) engraftment to putatively exploit the potential of cell therapy that has been seen in other central nervous system injury models.

Differential distribution of PI3K isoforms in spinal cord and dorsal root ganglia: potential roles in acute inflammatory pain.

PI3-kinases (PI3Ks) participate in nociception within spinal cord, dorsal root ganglion (DRG), and peripheral nerves. To extend our knowledge, we immunohistochemically stained for each of the 4 class I PI3K isoforms along with several cell-specific markers within the lumbar spinal cord, DRG, and sciatic nerve of naive rats. Intrathecal and intraplantar isoform specific antagonists were given as pretreatments before intraplantar carrageenan; pain behavior was then assessed over time.

Pig models of neurodegenerative disorders: Utilization in cell replacement-based preclinical safety and efficacy studies.

An important component for successful translation of cell replacement-based therapies into clinical practice is the utilization of large animal models to conduct efficacy and/or safety cell dosing studies. Over the past few decades, several large animal models (dog, cat, nonhuman primate) were developed and employed in cell replacement studies; however, none of these models appears to provide a readily available platform to conduct effective and large-scale preclinical studies. In recent years, numerous pig models of neurodegenerative disorders were developed using both a transgenic approach as well as invasive surgical techniques.

Effective long-term immunosuppression in rats by subcutaneously implanted sustained-release tacrolimus pellet: effect on spinally grafted human neural precursor survival.

Achievement of effective, safe and long-term immunosuppression represents one of the challenges in experimental allogeneic and xenogeneic cell and organ transplantation. The goal of the present study was to develop a reliable, long-term immunosuppression protocol in Sprague-Dawley (SD) rats by: 1) comparing the pharmacokinetics of four different subcutaneously delivered/implanted tacrolimus (TAC) formulations, including: i) caster oil/saline solution, ii) unilamellar or multilamellar liposomes, iii) biodegradable microspheres, and iv) biodegradable 3-month lasting pellets; and 2) defining the survival and immune response in animals receiving spinal injections of human neural precursors at 6 weeks to 3 months after cell grafting. In animals implanted with TAC pellets (3.

Human neural stem cell replacement therapy for amyotrophic lateral sclerosis by spinal transplantation.

Background: Mutation in the ubiquitously expressed cytoplasmic superoxide dismutase (SOD1) causes an inherited form of Amyotrophic Lateral Sclerosis (ALS). Mutant synthesis in motor neurons drives disease onset and early disease progression. Previous experimental studies have shown that spinal grafting of human fetal spinal neural stem cells (hNSCs) into the lumbar spinal cord of SOD1(G93A) rats leads to a moderate therapeutical effect as evidenced by local α-motoneuron sparing and extension of lifespan.

Survival and differentiation of human embryonic stem cell-derived neural precursors grafted spinally in spinal ischemia-injured rats or in naive immunosuppressed minipigs: a qualitative and quantitative study.

In previous studies, we have demonstrated that spinal grafting of human or rat fetal spinal neural precursors leads to amelioration of spasticity and improvement in ambulatory function in rats with spinal ischemic injury. In the current study, we characterize the survival and maturation of three different human embryonic stem (ES) cell line-derived neural precursors (hNPCs) once grafted into ischemia-injured lumbar spinal cord in rats or in naive immunosuppressed minipigs. Proliferating HUES-2, HUES-7, or HUES-9 colonies were induced to form embryoid bodies.

In vivo gene knockdown in rat dorsal root ganglia mediated by self-complementary adeno-associated virus serotype 5 following intrathecal delivery.

We report here in adult rat viral vector mediate-gene knockdown in the primary sensory neurons and the associated cellular and behavior consequences. Self-complementary adeno-associated virus serotype 5 (AAV5) was constructed to express green fluorescent protein (GFP) and a small interfering RNA (siRNA) targeting mammalian target of rapamycin (mTOR). The AAV vectors were injected via an intrathecal catheter.

Combinational spinal GAD65 gene delivery and systemic GABA-mimetic treatment for modulation of spasticity.

Background: Loss of GABA-mediated pre-synaptic inhibition after spinal injury plays a key role in the progressive increase in spinal reflexes and the appearance of spasticity. Clinical studies show that the use of baclofen (GABA(B) receptor agonist), while effective in modulating spasticity is associated with major side effects such as general sedation and progressive tolerance development. The goal of the present study was to assess if a combined therapy composed of spinal segment-specific upregulation of GAD65 (glutamate decarboxylase) gene once combined with systemic treatment with tiagabine (GABA uptake inhibitor) will lead to an antispasticity effect and whether such an effect will only be present in GAD65 gene over-expressing spinal segments.

Probing sporadic and familial Alzheimer's disease using induced pluripotent stem cells.

Our understanding of Alzheimer's disease pathogenesis is currently limited by difficulties in obtaining live neurons from patients and the inability to model the sporadic form of the disease. It may be possible to overcome these challenges by reprogramming primary cells from patients into induced pluripotent stem cells (iPSCs). Here we reprogrammed primary fibroblasts from two patients with familial Alzheimer's disease, both caused by a duplication of the amyloid-β precursor protein gene (APP; termed APP(Dp)), two with sporadic Alzheimer's disease (termed sAD1, sAD2) and two non-demented control individuals into iPSC lines.

Potent suppression of stretch reflex activity after systemic or spinal delivery of tizanidine in rats with spinal ischemia-induced chronic spastic paraplegia.

Background: Spasticity and rigidity are serious complications associated with spinal traumatic or ischemic injury. Clinical studies show that tizanidine (Tiz) is an effective antispasticity agent; however, the mechanism of this effect is still not clear. Tiz binds not only to α2-adrenoreceptors (AR) but also to imidazoline (I) receptors.

Transplantation of rat synapsin-EGFP-labeled embryonic neurons into the intact and ischemic CA1 hippocampal region: distribution, phenotype, and axodendritic sprouting.

A major limitation of neural transplantation studies is assessing the degree of host-graft interaction. In the present study, rat hippocampal/cortical embryonic neurons (E18) were infected with a lentivirus encoding enhanced green fluorescent protein (GFP) under control of the neuron-specific synapsin promoter, thus permitting robust identification of labeled neurons after in vivo grafting. Two weeks after transient forebrain ischemia or sham-surgery, GFP-expressing neurons were transplanted into CA1 hippocampal regions in immunosuppressed adult Wistar rats.

Optimization of immunosuppressive therapy for spinal grafting of human spinal stem cells in a rat model of ALS.

Previous rodent studies employing monotherapy or combined immunosuppressive regimens have demonstrated a variable degree of spinal xenograft survival in several spinal neurodegenerative models including spinal ischemia, trauma, or amyotrophic lateral sclerosis (ALS). Accordingly, the characterization of optimal immunosuppressive protocols for the specific neurodegenerative model is critical to ensure reliable assessment of potential long-term therapeutic effects associated with cell replacement. In the present study we characterized the survival of human spinal stem cells when grafted into the lumbar spinal cords of a rodent model of ALS, SOD1 (G93A) male and female rats (60-67 days old).

Cell-surface marker signatures for the isolation of neural stem cells, glia and neurons derived from human pluripotent stem cells.

Background: Neural induction of human pluripotent stem cells often yields heterogeneous cell populations that can hamper quantitative and comparative analyses. There is a need for improved differentiation and enrichment procedures that generate highly pure populations of neural stem cells (NSC), glia and neurons. One way to address this problem is to identify cell-surface signatures that enable the isolation of these cell types from heterogeneous cell populations by fluorescence activated cell sorting (FACS).

Suppression of stretch reflex activity after spinal or systemic treatment with AMPA receptor antagonist NGX424 in rats with developed baclofen tolerance.

Background And Purpose: Baclofen (a GABA(B) receptor agonist) is the most commonly used anti-spasticity agent in clinical practice. While effective when administered spinally or systemically, the development of progressive tolerance represents a serious limitation for its long-term use. The goal of the present study was to characterize the treatment potency after intrathecal or systemic treatment with the selective AMPA receptor antagonist NGX424 on stretch reflex activity (SRA) and background muscle activity (BMA) in rats with developed baclofen tolerance.

The ROCK inhibitor Y-27632 improves recovery of human embryonic stem cells after fluorescence-activated cell sorting with multiple cell surface markers.

Background: Due to the inherent sensitivity of human embryonic stem cells (hESCs) to manipulations, the recovery and survival of hESCs after fluorescence-activated cell sorting (FACS) can be low. Additionally, a well characterized and robust methodology for performing FACS on hESCs using multiple-cell surface markers has not been described. The p160-Rho-associated coiled kinase (ROCK) inhibitor, Y-27632, previously has been identified as enhancing survival of hESCs upon single-cell dissociation, as well as enhancing recovery from cryopreservation.

Analysis of dosing regimen and reproducibility of intraspinal grafting of human spinal stem cells in immunosuppressed minipigs.

In recent studies using a rat aortic balloon occlusion model, we have demonstrated that spinal grafting of rat or human neuronal precursors or human postmitotic hNT neurons leads to progressive amelioration of spasticity and rigidity and corresponding improvement in ambulatory function. In the present study, we characterized the optimal dosing regimen and safety profile of human spinal stem cells (HSSC) when grafted into the lumbar spinal cord segments of naive immunosuppressed minipigs. Gottingen-Minnesota minipigs (18-23 kg) were anesthetized with halothane, mounted into a spine-immobilization apparatus, and received five bilateral injections of HSSC delivered in 2, 4, 6, 8, or 10 μl of media targeted into L2-L5 central gray matter (lamina VII).

The pleotrophic effects of insulin-like growth factor-I on human spinal cord neural progenitor cells.

Most stem cell therapies involve direct, intraparachymal placement of neural progenitor cells. These cells provide physical support to the endogenous neuronal population and may be engineered to provide in situ growth factor support. Insulin-like growth factor-I (IGF-I) has potent neurotrophic and neuroprotective properties and is expressed by human neural stem cells (hNSCs).

Stem cells: comprehensive treatments for amyotrophic lateral sclerosis in conjunction with growth factor delivery.

Amyotrophic lateral sclerosis (ALS) is characterized by loss of both upper and lower motor neurons. ALS progression is complex and likely due to cellular dysfunction at multiple levels, including mitochondrial dysfunction, glutamate excitotoxicity, oxidative stress, axonal dysfunction, reactive astrocytosis, and mutant superoxide dismutase expression, therefore, treatment must provide neuronal protection from multiple insults. A significant amount of ALS research focuses on growth factor-based therapies.

The Rheb-mTOR pathway is upregulated in reactive astrocytes of the injured spinal cord.

Astrocytes in the CNS respond to tissue damage by becoming reactive. They migrate, undergo hypertrophy, and form a glial scar that inhibits axon regeneration. Therefore, limiting astrocytic responses represents a potential therapeutic strategy to improve functional recovery.

Spinal p38 mitogen-activated protein kinase mediates allodynia induced by first-degree burn in the rat.

Activation of p38 mitogen-activated protein kinase (MAPK) in the spinal cord has been implicated in the development and maintenance of pain states. In this study, we tested whether p38 MAPK is involved in the response to first-degree burn of the hind paw. This injury induces central sensitization leading to tactile allodynia and is mediated by activation of Ca(2+) permeable AMPA/kainate receptors through PKC and PKA.

Inhibition of spinal cytosolic phospholipase A(2) expression by an antisense oligonucleotide attenuates tissue injury-induced hyperalgesia.

Activation of the spinal phospholipase A(2) (PLA(2)) -cyclooxygenase (COX) -prostaglandin signaling pathway is widely implicated in nociceptive processing. Although the role of spinal COX isoforms in pain signal transmission has been extensively characterized, our knowledge of PLA(2) enzymes in this cascade is limited. Among all PLA(2) groups, cytosolic calcium-dependent PLA(2) group IVA (cPLA(2)IVA) appears to be the predominant PLA(2) enzyme in the spinal cord.

Spinal astrocyte glutamate receptor 1 overexpression after ischemic insult facilitates behavioral signs of spasticity and rigidity.

Using a rat model of ischemic paraplegia, we examined the expression of spinal AMPA receptors and their role in mediating spasticity and rigidity. Spinal ischemia was induced by transient occlusion of the descending aorta combined with systemic hypotension. Spasticity/rigidity were identified by simultaneous measurements of peripheral muscle resistance (PMR) and electromyography (EMG) before and during ankle flexion.