Search results for "Nerve regeneration"
showing 10 items of 49 documents
Functions of histone modifications and histone modifiers in Schwann cells.
2019
Schwann cells (SCs) are the main glial cells present in the peripheral nervous system (PNS). Their primary functions are to insulate peripheral axons to protect them from the environment and to enable fast conduction of electric signals along big caliber axons by enwrapping them in a thick myelin sheath rich in lipids. In addition, SCs have the peculiar ability to foster axonal regrowth after a lesion by demyelinating and converting into repair cells that secrete neurotrophic factors and guide axons back to their former target to finally remyelinate regenerated axons. The different steps of SC development and their role in the maintenance of PNS integrity and regeneration after lesion are c…
Taking Advantage of Nature’s Gift: Can Endogenous Neural Stem Cells Improve Myelin Regeneration?
2016
Irreversible functional deficits in multiple sclerosis (MS) are directly correlated to axonal damage and loss. Neurodegeneration results from immune-mediated destruction of myelin sheaths and subsequent axonal demyelination. Importantly, oligodendrocytes, the myelinating glial cells of the central nervous system, can be replaced to some extent to generate new myelin sheaths. This endogenous regeneration capacity has so far mainly been attributed to the activation and recruitment of resident oligodendroglial precursor cells. As this self-repair process is limited and increasingly fails while MS progresses, much interest has evolved regarding the development of remyelination-promoting strateg…
Profilin 1 delivery tunes cytoskeletal dynamics toward CNS axon regeneration
2020
After trauma, regeneration of adult CNS axons is abortive, causing devastating neurologic deficits. Despite progress in rehabilitative care, there is no effective treatment that stimulates axonal growth following injury. Using models with different regenerative capacities, followed by gain- and loss-of-function analysis, we identified profilin 1 (Pfn1) as a coordinator of actin and microtubules (MTs), powering axonal growth and regeneration. In growth cones, Pfn1 increased actin retrograde flow, MT growth speed, and invasion of filopodia by MTs, orchestrating cytoskeletal dynamics toward axonal growth. In vitro, active Pfn1 promoted MT growth in a formin-dependent manner, whereas localizati…
Irreversible changes occurring in long-term denervated Schwann cells affect delayed nerve repair.
2017
OBJECTIVEMultiple factors may affect functional recovery after peripheral nerve injury, among them the lesion site and the interval between the injury and the surgical repair. When the nerve segment distal to the lesion site undergoes chronic degeneration, the ensuing regeneration (when allowed) is often poor. The aims of the current study were as follows: 1) to examine the expression changes of the neuregulin 1/ErbB system during long-term nerve degeneration; and 2) to investigate whether a chronically denervated distal nerve stump can sustain nerve regeneration of freshly axotomized axons.METHODSThis study used a rat surgical model of delayed nerve repair consisting of a cross suture betw…
A predominantly glial origin of axonal ribosomes after nerve injury
2017
Axonal mRNA transport and local protein synthesis are crucial for peripheral axon regeneration. To date, it remains unclear how ribosomes localize to axons. They may be co-transported with mRNAs or, as suggested by recent studies, transferred from Schwann cells (SC). Here, we generated transgenic "RiboTracker" mice expressing tdTomato-tagged ribosomal protein L4 in specific cell types when crossed with Cre lines. Two neuronal RiboTracker-Cre lines displayed extremely low levels of axonal L4-tdTomato-positive ribosomes. In contrast, two glial RiboTracker-Cre lines revealed tagged ribosomes in sciatic nerve (SN) axons with increasing amounts after injury. Furthermore, non-RiboTracker dorsal r…
Validity and reliability of the CatWalk system as a static and dynamic gait analysis tool for the assessment of functional nerve recovery in small an…
2017
Introduction: A range of behavioral testing paradigms have been developed for the research of central and peripheral nerve injuries with the help of small animal models. Following any nerve repair strategy, improved functional outcome may be the most important evidence of axon regeneration. A novel automated gait analysis system, the CatWalk™, can measure dynamic as well as static gait patterns of small animals. Of most interest in detecting functional recovery are in particular dynamic gait parameters, coordination measures, and the intensity of the animals paw prints. This article is designed to lead to a more efficient choice of CatWalk parameters in future studies concerning the functio…
Seeding nerve sutures with minced nerve-graft (MINE-G): a simple method to improve nerve regeneration in rats
2017
Background: The aim of this study was to assess the effect of seeding the distal nerve suture with nerve fragments in rats. Methods: On 20 rats, a 15 mm sciatic nerve defect was reconstructed with a nerve autograft. In the Study Group (10 rats), a minced 1 mm nerve segment was seeded around the nerve suture. In the Control Group (10 rats), a nerve graft alone was used. At 4 and 12 weeks, a walking track analysis with open field test (WTA), hystomorphometry (number of myelinated fibers (n), fiber density (FD) and fiber area (FA) and soleus and gastrocnemius muscle weight ratios (MWR) were evaluated. The Student t-test was used for statistical analysis. Results: At 4 and 12 weeks the Study Gr…
In Vivo Reprogramming for Brain and Spinal Cord Repair.
2015
AbstractCell reprogramming technologies have enabled the generation of various specific cell types including neurons from readily accessible patient cells, such as skin fibroblasts, providing an intriguing novel cell source for autologous cell transplantation. However, cell transplantation faces several difficult hurdles such as cell production and purification, long-term survival, and functional integration after transplantation. Recently,in vivoreprogramming, which makes use of endogenous cells for regeneration purpose, emerged as a new approach to circumvent cell transplantation. There has been evidence forin vivoreprogramming in the mouse pancreas, heart, and brain and spinal cord with …
CONSISTENT BONE MARROW-DERIVED CELL MOBILIZATION FOLLOWING REPEATED SHORT COURSES OF GRANULOCYTE-COLONY-STIMULATING FACTOR IN PATIENTS WITH AMYOTROPH…
2009
Background and aims. The aim of this study was to evaluate and characterize the feasibility and safety of bone marrow-derived cell (BMC) mobilization following repeated courses of granulocyte-colony stimulating factor (G-CSF) in patients with amyotrophic lateral sclerosis (ALS). Methods. Between January 2006 and March 2007, 26 ALS patients entered a multicenter trial that included four courses of BMC mobilization at 3-month intervals. In each course, G-CSF (5 mu g/kg b.i.d.) was administered for four consecutive days; 18% mannitol was also given. Mobilization was monitored by flow cytometry analysis of circulating CD34(+) cells and by in vitro colony assay for clonogenic progenitors. Co-exp…
Effects of botulinum toxin type A on vibration induced facilitation of motor evoked potentials in spasmodic torticollis.
2004
It has not been clarified if botulinum toxin (BTX) injection leads to muscle spindle dysfunction in man. This study aimed to test the hypothesis that BTX application reduces the facilitation of a magnetic evoked response (MEP).We used the vibration induced facilitation of an MEP of the sternocleidomastoid muscle (SCM) as a surrogate marker for muscle spindle function in 20 healthy subjects and 10 patients with idiopathic rotational torticollis in whom BTX was injected unilaterally.The increase in the amplitude and area of the MEPs in the clinically not affected and untreated SCM of the patients did not differ significantly from the controls. At baseline, the vibration induced increase in th…