Directing the organization of cells into a tissue with defined architectures is one use of biomaterials for regenerative medicine. To this end, hydrogels are widely investigated as they have mechanical properties similar to native soft tissues and can be formed in situ to conform to a defect. Herein, we describe the development of porous hydrogel tubes fabricated through a two-step polymerization process with an intermediate microsphere phase that provides macroscale porosity (66.5%) for cell infiltration. These tubes were investigated in a spinal cord injury model, with the tubes assembled to conform to the injury and to provide an orientation that guides axons through the injury. Implanted tubes had good apposition and were integrated with the host tissue due to cell infiltration, with a transient increase in immune cell infiltration at 1 week that resolved by 2 weeks post injury compared to a gelfoam control. The glial scar was significantly reduced relative to control, which enabled robust axon growth along the inner and outer surface of the tubes. Axon density within the hydrogel tubes (1744 axons/mm2) was significantly increased more than 3-fold compared to the control (456 axons/mm2), with approximately 30% of axons within the tube myelinated. Furthermore, implantation of hydrogel tubes enhanced functional recovery relative to control. This modular assembly of porous tubes to fill a defect and directionally orient tissue growth could be extended beyond spinal cord injury to other tissues, such as vascular or musculoskeletal tissue. STATEMENT OF SIGNIFICANCE: Tissue engineering approaches that mimic the native architecture of healthy tissue are needed following injury. Traditionally, pre-molded scaffolds have been implemented but require a priori knowledge of wound geometries. Conversely, hydrogels can conform to any injury, but do not guide bi-directional regeneration. In this work, we investigate the feasibility of a system of modular hydrogel tubes to promote bi-directional regeneration after spinal cord injury. This system allows for tubes to be cut to size during surgery and implanted one-by-one to fill any injury, while providing bi-directional guidance. Moreover, this system of tubes can be broadly applied to tissue engineering approaches that require a modular guidance system, such as repair to vascular or musculoskeletal tissues.
- MeSH
- axony účinky léků patologie MeSH
- hydrogely farmakologie MeSH
- jizva patologie MeSH
- lokomoce účinky léků MeSH
- maleimidy chemie MeSH
- mikrosféry MeSH
- myelinová pochva účinky léků metabolismus MeSH
- myši inbrední C57BL MeSH
- neuroglie patologie MeSH
- polyethylenglykoly chemie MeSH
- polymerizace MeSH
- poranění míchy patologie patofyziologie MeSH
- poréznost MeSH
- reagencia zkříženě vázaná chemie MeSH
- regenerace nervu účinky léků MeSH
- tkáňové podpůrné struktury chemie MeSH
- zadní končetina účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, N.I.H., Extramural MeSH
PURPOSE: To study the dynamics and clinical determinants of chronic retinal nerve fiber layer thickness (RNFL) loss after methanol-induced optic neuropathy. DESIGN: Prospective cohort study. METHODS: All patients underwent complete ophthalmic evaluation including spectral-domain optical coherence tomography 3 times during 4 years of observation: 4.9 (±0.6), 25.0 (±0.6), and 49.9 (±0.5) months after discharge. PARTICIPANTS: Eighty-four eyes of 42 survivors of methanol poisoning, mean age (standard deviation) of 45.7 (±4.4) years; and 82 eyes of 41 controls, mean age 44.0 (±4.2) years. MAIN OUTCOME MEASURES: Global and temporal RNFL loss. RESULTS: Abnormal RNFL thickness was registered in 13 of 42 (31%) survivors of methanol poisoning and chronic axonal loss in 10 of 42 (24%) patients. Significant decrease of global/temporal RNFL thickness during the observation period was found in the study population compared to the controls (P < .001). The risk estimate of chronic global RNFL loss for arterial blood pH < 7.3 at admission was 11.65 (95% confidence interval 1.91-71.12) after adjusting for age and sex. The patients with chronic axonal degeneration demonstrated progressive visual loss in 7 of 10 cases. The patients with abnormal RNFL thickness had magnetic resonance signs of brain damage in 10 of 13 vs 8 of 29 cases with normal RNFL thickness (P = .003). Signs of brain hemorrhages were present in 7 of 13 patients with abnormal RNFL thickness vs 5 of 29 cases with normal RNFL thickness (P = .015). CONCLUSIONS: Methanol-induced optic neuropathy may lead to chronic retinal axonal loss during the following years. Arterial blood pH on admission is the strongest predictor of chronic RNFL thickness decrease. Chronic retinal neurodegeneration is associated with the progressive loss of visual functions and necrotic brain lesions.
- MeSH
- akutní nemoc MeSH
- axony účinky léků patologie MeSH
- časové faktory MeSH
- chronická nemoc MeSH
- discus nervi optici účinky léků patologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- magnetická rezonanční tomografie MeSH
- methanol otrava MeSH
- mozek patologie MeSH
- následné studie MeSH
- nemoci zrakového nervu chemicky indukované diagnóza patofyziologie MeSH
- neurony sítnice účinky léků patologie MeSH
- optická koherentní tomografie metody MeSH
- počítačová rentgenová tomografie MeSH
- progrese nemoci MeSH
- prospektivní studie MeSH
- retinální gangliové buňky účinky léků patologie MeSH
- rozpouštědla otrava MeSH
- zraková ostrost MeSH
- zraková pole MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Spinal cord injury (SCI) is a debilitating condition which is characterized by an extended secondary injury due to the presence of inflammatory local milieu. Epigallocatechin gallate (EGCG) appears to possess strong neuroprotective properties. Here, we evaluated the beneficial effect of EGCG on recovery from SCI. Male Wistar rats were given either EGCG or saline directly to the injured spinal cord and thereafter a daily IP injection. Behavior recovery was monitored by BBB, plantar, rotarod and flat-beam tests. The levels of inflammatory cytokines were determined on days 1, 3, 7, 10 and 14 after SCI. Additionally, NF-κB pathway activity was evaluated. The results demonstrated that EGCG-treated rats displayed a superior behavioral performance in a flat beam test, higher axonal sprouting and positive remodelation of glial scar. Cytokine analysis revealed a reduction in IL-6, IL2, MIP1α and RANTES levels on days 1 and 3, and an upregulation of IL-4, IL-12p70 and TNFα 1 day following SCI in EGCG-treated rats. Treatment with EGCG was effective in decreasing the nuclear translocation of subunit p65 (RelA) of the NF-κB dimer, and therefore canonical NF-κB pathway attenuation. A significant increase in the gene expression of growth factors (FGF2 and VEGF), was noted in the spinal cord of EGCG-treated rats. Further, EGCG influenced expression of M1 and M2 macrophage markers. Our results have demonstrated a therapeutic value of EGCG in SCI, as observed by better behavioral performance measured by flat beam test, modulation of inflammatory cytokines and induction of higher axonal sprouting.
- MeSH
- axony účinky léků MeSH
- čaj chemie MeSH
- chování zvířat účinky léků MeSH
- cytokiny metabolismus MeSH
- katechin aplikace a dávkování analogy a deriváty MeSH
- mediátory zánětu metabolismus MeSH
- myelitida komplikace metabolismus MeSH
- neuroprotektivní látky aplikace a dávkování MeSH
- NF-kappa B metabolismus MeSH
- poranění míchy komplikace metabolismus patologie prevence a kontrola MeSH
- potkani Wistar MeSH
- regenerace nervu účinky léků MeSH
- signální transdukce účinky léků MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Currently, there is no effective strategy for the treatment of spinal cord injury (SCI). A suitable combination of modern hydrogel materials, modified to effectively bridge the lesion cavity, combined with appropriate stem cell therapy seems to be a promising approach to repair spinal cord damage. We demonstrate the synergic effect of porosity and surface modification of hydrogels on mesenchymal stem cell (MSC) adhesiveness in vitro and their in vivo survival in an experimental model of SCI. MSCs were seeded on four different hydrogels: hydroxypropylmethacrylate-RGD prepared by heterophase separation (HPMA-HS-RGD) and three other hydrogels polymerized in the presence of a solid porogen: HPMA-SP, HPMA-SP-RGD, and hydroxy ethyl methacrylate [2-(methacryloyloxy)ethyl] trimethylammonium chloride (HEMA-MOETACl). Their adhesion capability and cell survival were evaluated at 1, 7, and 14 days after the seeding of MSCs on the hydrogel scaffolds. The cell-polymer scaffolds were then implanted into hemisected rat spinal cord, and MSC survival in vivo and the ingrowth of endogenous tissue elements were evaluated 1 month after implantation. In vitro data demonstrated that HEMA-MOETACl and HPMA-SP-RGD hydrogels were superior in the number of cells attached. In vivo, the highest cell survival was found in the HEMA-MOETACl hydrogels; however, only a small ingrowth of blood vessels and axons was observed. Both HPMA-SP and HPMA-SP-RGD hydrogels showed better survival of MSCs compared with the HPMA-HS-RGD hydrogel. The RGD sequence attached to both types of HPMA hydrogels significantly influenced the number of blood vessels inside the implanted hydrogels. Further, the porous structure of HPMA-SP hydrogels promoted a statistically significant greater ingrowth of axons and less connective tissue elements into the implant. Our results demonstrate that the physical and chemical properties of the HPMA-SP-RGD hydrogel show the best combination for bridging a spinal cord lesion, while the HEMA-MOETACl hydrogel serves as the best carrier of MSCs.
- MeSH
- axony účinky léků fyziologie MeSH
- buněčná adheze MeSH
- cholin analogy a deriváty chemie farmakologie MeSH
- fyziologická neovaskularizace MeSH
- hydrogely chemie farmakologie MeSH
- kmenové buňky cytologie účinky léků fyziologie MeSH
- krysa rodu rattus MeSH
- methakryláty chemie farmakologie MeSH
- mícha krevní zásobení účinky léků růst a vývoj patologie MeSH
- oligopeptidy chemie farmakologie MeSH
- poranění míchy terapie MeSH
- poréznost MeSH
- potkani Wistar MeSH
- regenerace nervu účinky léků MeSH
- tkáňové podpůrné struktury MeSH
- transplantace kmenových buněk MeSH
- viabilita buněk MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- MeSH
- atrofie MeSH
- axony účinky léků MeSH
- bílá hmota patologie účinky léků MeSH
- cílená molekulární terapie MeSH
- kongresy jako téma MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- myši MeSH
- randomizované kontrolované studie jako téma MeSH
- roztroušená skleróza * farmakoterapie patofyziologie MeSH
- šedá hmota patologie účinky léků MeSH
- výsledek terapie MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- Publikační typ
- novinové články MeSH
OBJECTIVES: Our previous experiments proved that methylprednisolone (MP) can significantly reduce axonal impairment accompanying extracellular oedema induced by the osmotic challenge (load) on the blood-brain barrier (BBB). The aim of the present work was to identify whether MP can affect myelin impairment accompanying intracellular oedema induced by water intoxication. METHODS: For induction of cellular brain oedema, the standard model of water intoxication was chosen. Animals received distilled water in amount corresponding to 15% of the animal's body weight. The volume was divided into three parts and administered intraperitoneally in 8 hours interval. Axonal changes were recognized as signs of myelin disintegration (oedematous distensions, axonal swelling, vesicles, varicosities) at histological sections stained with Black Gold and classified into four grades of myelin degradation. Hippocampal CA1 and CA3 areas and the dentate gyrus were selected for the study. Methylprednisolone was administered either intraperitoneally or intracarotically. Its effect was studied in two different time intervals: in the acute group (30 minutes after hyperhydration and MP application) and in chronic one (1 week after hyperhydration and MP application). Results: In both the acute and chronic groups, cellular oedema induced by water intoxication brought about apparent damage of myelin (compared to control animals p<0.0001). Intracarotic injection of MP was not able to influence myelin integrity changes either in the acute or in chronic group. However, intraperitoneal administration of MP increased the level of myelin deterioration in the acute group (p 0.05), but improved myelin changes in the chronic group (p<0.005). Conclusion: The effect of MP on axonal impairment during cellular brain oedema induced by water intoxication differs from that during the extracellular osmotic oedema. In the extracellular oedema, cellular metabolism is not significantly affected and myelin changes can be influenced by the neuroprotective effect of MP. The primary cause of cellular oedema is a disorder of cellular metabolism and myelin impairment is one of the structural consequences of such disorder. That is why the myelin changes are not affected by MP administration in a consistent and specific manner.
- MeSH
- axony účinky léků metabolismus patologie MeSH
- edém mozku farmakoterapie metabolismus patologie MeSH
- glukokortikoidy farmakologie MeSH
- hematoencefalická bariéra účinky léků metabolismus patologie MeSH
- intoxikace vodou farmakoterapie metabolismus patologie MeSH
- krysa rodu rattus MeSH
- methylprednisolon farmakologie MeSH
- myelinová pochva účinky léků metabolismus patologie MeSH
- nervová vlákna myelinizovaná účinky léků metabolismus patologie MeSH
- neuroprotektivní látky farmakologie MeSH
- osmotický tlak účinky léků MeSH
- potkani Wistar MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
BACKGROUND: It is difficult to repair nerve if proximal stump is unavailable or autogenous nerve grafts are insufficient for reconstructing extensive nerve damage. Therefore, alternative methods have been developed, including lateral anastomosis based on axons' ability to send out collateral sprouts into denervated nerve. The different capacity of a sensory or motor axon to send a sprout is controversial and may be controlled by cytokines and/or neurotrophic factors like ciliary neurotrophic factor (CNTF). The aim of the present study was to quantitatively assess collateral sprouts sent out by intact motor and sensory axons in the end-to-side neurorrhaphy model following intrathecal administration of CNTF in comparison with phosphate buffered saline (vehiculum) and Cerebrolysin. The distal stump of rat transected musculocutaneous nerve (MCN) was attached in an end-to-side fashion with ulnar nerve. CNTF, Cerebrolysin and vehiculum were administered intrathecally for 2 weeks, and all animals were allowed to survive for 2 months from operation. Numbers of spinal motor and dorsal root ganglia neurons were estimated following their retrograde labeling by Fluoro-Ruby and Fluoro-Emerald applied to ulnar and musculocutaneous nerve, respectively. Reinnervation of biceps brachii muscles was assessed by electromyography, behavioral test, and diameter and myelin sheath thickness of regenerated axons. RESULTS: Vehiculum or Cerebrolysin administration resulted in significantly higher numbers of myelinated axons regenerated into the MCN stumps compared with CNTF treatment. By contrast, the mean diameter of the myelinated axons and their myelin sheath thickness in the cases of Cerebrolysin- or CNTF-treated animals were larger than were those for rats treated with vehiculum. CNTF treatment significantly increased the percentage of motoneurons contributing to reinnervation of the MCN stumps (to 17.1%) when compared with vehiculum or Cerebrolysin treatments (at 9.9 or 9.6%, respectively). Reduced numbers of myelinated axons and simultaneously increased numbers of motoneurons contributing to reinnervation of the MCN improved functional reinnervation of the biceps brachii muscle after CNTF treatment. CONCLUSION: The present experimental study confirms end-to-side neurorrhaphy as an alternative method for reconstructing severed peripheral nerves. CNTF promotes motor reinnervation of the MCN stump after its end-to-side neurorrhaphy with ulnar nerve and improves functional recovery of the biceps brachii muscle.
- MeSH
- axony účinky léků MeSH
- ciliární neurotrofický faktor aplikace a dávkování MeSH
- krysa rodu rattus MeSH
- motorické neurony účinky léků MeSH
- nervový transfer metody MeSH
- nervus musculocutaneus účinky léků zranění patofyziologie MeSH
- poranění periferního nervu patofyziologie terapie MeSH
- potkani Wistar MeSH
- regenerace nervu účinky léků fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- axony fyziologie účinky léků MeSH
- batrachotoxiny diagnostické užití MeSH
- buněčná membrána fyziologie účinky léků MeSH
- financování organizované MeSH
- gating iontového kanálu fyziologie MeSH
- lidé MeSH
- sodíkové kanály účinky léků MeSH
- statistické modely MeSH
- teoretické modely MeSH
- Check Tag
- lidé MeSH
- MeSH
- akční potenciály účinky léků MeSH
- axony fyziologie účinky léků MeSH
- indoly farmakologie MeSH
- kovy škodlivé účinky MeSH
- krysa rodu rattus MeSH
- oxidační stres MeSH
- periferní nervy MeSH
- reaktivní formy kyslíku škodlivé účinky MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
