Chitin conduits modified with DNA-peptide coating promote the peripheral nerve regeneration

2021 ◽  
Author(s):  
Songyang Liu ◽  
Liping Zhou ◽  
Ci Li ◽  
Tiantian Min ◽  
Changfeng Lu ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Amide Bond ◽  
Primary Amines ◽  
Direct Reaction ◽  
Ct Dna ◽  
Peptide Coating

Abstract Peripheral nerve injury (PNI) is one of the common clinical injuries which needs to be addressed. Previous studies demonstrated the effectiveness of using biodegradable chitin (CT) conduits small gap tubulization technology as a substitute for traditional epineurial neurorrhaphy. Aiming to improve the effectiveness of CT conduits in repairing PNI, we modified their surface with a DNA-peptide coating. The coating consisted of single strand DNA (ssDNA) and its complementary DNA’-peptide mimics. First, we immobilize ssDNA (DNA1+2) on CT conduits by EDC/NHS method to construct CT/DNA conduits. EDC/NHS was used to activate carboxyl groups of modified ssDNA for direct reaction with primary amines on the chitin via amide bond formation. Then, DNA1’-BDNF+DNA2’-VEGF mimic peptide （RGI+KLT）were bonded to CT/DNA conduits by complementary base pairing principle at room temperature to form CT/RGI+KLT conduits. When the surrounding environment rose to a certain point (37℃), the CT/RGI+KLT conduits achieved sustainable release of DNA’-peptide. In vitro, the CT conduits modified with the DNA-peptide coating promoted the proliferation and secretion of Schwann cells by maintaining their repair state. It also promoted the proliferation of HUVECs and axon outgrowth of DRG explants. In vivo, CT/RGI+KLT conduits promoted regeneration of injured nerves and functional recovery of target muscles, which was facilitated by the synergistic contribution of angiogenesis and neurogenesis. Our research brings DNA and DNA-peptide hybrids into the realm of tissue engineering to repair peripheral nerve injury.

scholarly journals Macrophage-specific RhoA knockout delays Wallerian degeneration after peripheral nerve injury in mice

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jiawei Xu ◽  
Jinkun Wen ◽  
Lanya Fu ◽  
Liqiang Liao ◽  
Ying Zou ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Axonal Regeneration ◽  
Wallerian Degeneration ◽  
Future Application ◽  
Injured Nerve

Abstract Background Plenty of macrophages are recruited to the injured nerve to play key roles in the immunoreaction and engulf the debris of degenerated axons and myelin during Wallerian degeneration, thus creating a conducive microenvironment for nerve regeneration. Recently, drugs targeting the RhoA pathway have been widely used to promote peripheral axonal regeneration. However, the role of RhoA in macrophage during Wallerian degeneration and nerve regeneration after peripheral nerve injury is still unknown. Herein, we come up with the hypothesis that RhoA might influence Wallerian degeneration and nerve regeneration by affecting the migration and phagocytosis of macrophages after peripheral nerve injury. Methods Immunohistochemistry, Western blotting, H&E staining, and electrophysiology were performed to access the Wallerian degeneration and axonal regeneration after sciatic nerve transection and crush injury in the LyzCre+/−; RhoAflox/flox (cKO) mice or Lyz2Cre+/− (Cre) mice, regardless of sex. Macrophages’ migration and phagocytosis were detected in the injured nerves and the cultured macrophages. Moreover, the expression and potential roles of ROCK and MLCK were also evaluated in the cultured macrophages. Results 1. RhoA was specifically knocked out in macrophages of the cKO mice; 2. The segmentation of axons and myelin, the axonal regeneration, and nerve conduction in the injured nerve were significantly impeded while the myoatrophy was more severe in the cKO mice compared with those in Cre mice; 3. RhoA knockout attenuated the migration and phagocytosis of macrophages in vivo and in vitro; 4. ROCK and MLCK were downregulated in the cKO macrophages while inhibition of ROCK and MLCK could weaken the migration and phagocytosis of macrophages. Conclusions Our findings suggest that RhoA depletion in macrophages exerts a detrimental effect on Wallerian degeneration and nerve regeneration, which is most likely due to the impaired migration and phagocytosis of macrophages resulted from disrupted RhoA/ROCK/MLCK pathway. Since previous research has proved RhoA inhibition in neurons was favoring for axonal regeneration, the present study reminds us of that the cellular specificity of RhoA-targeted drugs is needed to be considered in the future application for treating peripheral nerve injury.

scholarly journals Exosomes from Human Gingiva-Derived Mesenchymal Stem Cells Combined with Biodegradable Chitin Conduits Promote Rat Sciatic Nerve Regeneration

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Rao ◽  
Dianying Zhang ◽  
Tengjiaozi Fang ◽  
Changfeng Lu ◽  
Bo Wang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Peripheral Nerve Regeneration

At present, repair methods for peripheral nerve injury often fail to get satisfactory result. Although various strategies have been adopted to investigate the microenvironment after peripheral nerve injury, the underlying molecular mechanisms of neurite outgrowth remain unclear. In this study, we evaluate the effects of exosomes from gingival mesenchymal stem cells (GMSCs) combined with biodegradable chitin conduits on peripheral nerve regeneration. GMSCs were isolated from human gingival tissue and characterized by surface antigen analysis and in vitro multipotent differentiation. The cell supernatant was collected to isolate the exosomes. The exosomes were characterized by transmission electron microscopy, Western blot, and size distribution analysis. The effects of exosomes on peripheral nerve regeneration in vitro were evaluated by coculture with Schwann cells and DRGs. The chitin conduit was prepared and combined with the exosomes to repair rat sciatic nerve defect. Histology, electrophysiology, and gait analysis were used to test the effects of exosomes on sciatic nerve function recovery in vivo. We have successfully cultured GMSCs and isolated exosomes. The exosomes from GMSCs could significantly promote Schwann cell proliferation and DRG axon growth. The in vivo studies showed that chitin conduit combined with exosomes from GMSCs could significantly increase the number and diameter of nerve fibers and promote myelin formation. In addition, muscle function, nerve conduction function, and motor function were also obviously recovered. In summary, this study suggests that GMSC-derived exosomes combined with biodegradable chitin conduits are a useful and novel therapeutic intervention in peripheral nerve repair.

scholarly journals Approaches to Peripheral Nerve Repair: Generations of Biomaterial Conduits Yielding to Replacing Autologous Nerve Grafts in Craniomaxillofacial Surgery

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Robert Gaudin ◽  
Christian Knipfer ◽  
Anders Henningsen ◽  
Ralf Smeets ◽  
Max Heiland ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Nerve Repair ◽  
Treatment Options ◽  
Donor Site ◽  
Nerve Reconstruction ◽  
Craniomaxillofacial Surgery

Peripheral nerve injury is a common clinical entity, which may arise due to traumatic, tumorous, or even iatrogenic injury in craniomaxillofacial surgery. Despite advances in biomaterials and techniques over the past several decades, reconstruction of nerve gaps remains a challenge. Autografts are the gold standard for nerve reconstruction. Using autografts, there is donor site morbidity, subsequent sensory deficit, and potential for neuroma development and infection. Moreover, the need for a second surgical site and limited availability of donor nerves remain a challenge. Thus, increasing efforts have been directed to develop artificial nerve guidance conduits (ANCs) as new methods to replace autografts in the future. Various synthetic conduit materials have been testedin vitroandin vivo,and several first- and second-generation conduits are FDA approved and available for purchase, while third-generation conduits still remain in experimental stages. This paper reviews the current treatment options, summarizes the published literature, and assesses future prospects for the repair of peripheral nerve injury in craniomaxillofacial surgery with a particular focus on facial nerve regeneration.

scholarly journals Pleiotrophin Cellular Localization in Nerve Regeneration after Peripheral Nerve Injury

2005 ◽  
Vol 53 (8) ◽  
pp. 971-977 ◽  
Author(s):  
Brigitte Blondet ◽  
Gilles Carpentier ◽  
Fouad Lafdil ◽  
Jose Courty
Keyword(s):  
Endothelial Cells ◽  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Schwann Cells ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Cellular Localization ◽  
Heparin Binding

Pleiotrophin (PTN) is a member of the family of heparin-binding growth factors that displays mitogenic activities and promotes neurite outgrowth in vitro. In vivo, PTN is widely expressed along pathways of developing axons during the late embryonic and early postnatal period. Although the level of PTN gene expression is very low during adulthood, activation of the gene may occur during recovery from injury and seems to play an important role in tissue regeneration processes. In this study, we investigated whether PTN was involved in the regenerative process of injured peripheral nerves. To refer localization of the fluorescent markers to myelinated axons, we developed a specific computer tool for colocalization of fluorescence images with phase contrast images. Immunohistochemical analysis showed PTN in different types of nonneural cells in distal nerve segments, including Schwann cells, macrophages, and endothelial cells, but not in axons. Schwann cells exhibited PTN immunoreactivity as early as 2 days after injury, whereas PTN-positive macrophages were found 1 week later. Strong PTN immunoreactivity was noted in endothelial cells at all time points. These findings support the idea that PTN participates in the adaptive response to peripheral nerve injury. A better understanding of its contribution may suggest new strategies for enhancing peripheral nerve regeneration.

scholarly journals Localized and Sustained Delivery of Erythropoietin from PLGA Microspheres Promotes Functional Recovery and Nerve Regeneration in Peripheral Nerve Injury

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Wei Zhang ◽  
Yuan Gao ◽  
Yan Zhou ◽  
Jianheng Liu ◽  
Licheng Zhang ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Intraperitoneal Injection ◽  
Sustained Delivery ◽  
Plga Microspheres ◽  
Neuroprotective Effects ◽  
Injury Recovery ◽  
Daily Intraperitoneal Injection

Erythropoietin (EPO) has been demonstrated to exert neuroprotective effects on peripheral nerve injury recovery. Though daily intraperitoneal injection of EPO during a long period of time was effective, it was a tedious procedure. In addition, only limited amount of EPO could reach the injury sites by general administration, and free EPO is easily degradedin vivo. In this study, we encapsulated EPO in poly(lactide-co-glycolide) (PLGA) microspheres. Bothin vitroandin vivorelease assays showed that the EPO-PLGA microspheres allowed sustained release of EPO within a period of two weeks. After administration of such EPO-PLGA microspheres, the peripheral nerve injured rats had significantly better recovery compared with those which received daily intraperitoneal injection of EPO, empty PLGA microspheres, or saline treatments. This was supported by the functional, electrophysiological, and histological evaluations of the recovery done at week 8 postoperatively. We conclude that sustained delivery of EPO could be achieved by using EPO-PLGA microspheres, and such delivery method could further enhance the recovery function of EPO in nerve injury recovery.

scholarly journals Nerve Suture Combined With ADSCs Injection Under Real-Time and Dynamic NIR-II Fluorescence Imaging in Peripheral Nerve Regeneration in vivo

2021 ◽  
Vol 9 ◽  
Author(s):  
Shixian Dong ◽  
Sijia Feng ◽  
Yuzhou Chen ◽  
Mo Chen ◽  
Yimeng Yang ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Real Time ◽  
Fluorescence Imaging ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Peripheral Nerve Regeneration ◽  
Post Injection ◽  
Nerve Suture

Peripheral nerve injury gives rise to devastating conditions including neural dysfunction, unbearable pain and even paralysis. The therapeutic effect of current treatment for peripheral nerve injury is unsatisfactory, resulting in slow nerve regeneration and incomplete recovery of neural function. In this study, nerve suture combined with ADSCs injection was adopted in rat model of sciatic nerve injury. Under real-time visualization of the injected cells with the guidance of NIR-II fluorescence imaging in vivo, a spatio-temporal map displaying cell migration from the proximal injection site (0 day post-injection) of the nerve to the sutured site (7 days post-injection), and then to the distal section (14 days post-injection) was demonstrated. Furthermore, the results of electromyography and mechanical pain threshold indicated nerve regeneration and functional recovery after the combined therapy. Therefore, in the current study, the observed ADSCs migration in vivo, electrophysiological examination results and pathological changes all provided robust evidence for the efficacy of the applied treatment. Our approach of nerve suture combined with ADSCs injection in treating peripheral nerve injury under real-time NIR-II imaging monitoring in vivo added novel insights into the treatment for peripheral nerve injury, thus further enhancing in-depth understanding of peripheral nerve regeneration and the mechanism behind.

scholarly journals SIRT6 inhibition delays peripheral nerve recovery by suppressing migration, phagocytosis and M2-polarization of macrophages

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ying Zou ◽  
Jiaqi Zhang ◽  
Jiawei Xu ◽  
Lanya Fu ◽  
Yizhou Xu ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Macrophage Polarization ◽  
Nerve Degeneration ◽  
M2 Polarization ◽  
M1 Macrophage ◽  
Nerve Recovery

Abstract Background Silent information regulator 6 (SIRT6) is a mammalian homolog of the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase sirtuin family. Prior evidences suggested that the anti-inflammatory function of SIRT6 after spinal cord and brain injury, and it plays a crucial role in macrophages polarization of adipose tissue and skin. However, the role of SIRT6 in macrophages involved peripheral nerve injury is still unknown. Given the prominent role of macrophages in peripheral nerve recovery, we aim to investigate the role of SIRT6 in the regulation of phenotypes shift and functions in macrophages after peripheral nerve injury. Results In the present study, we first identified a significant increase of SIRT6 expression during nerve degeneration and macrophages phagocytosis. Next, we found nerve recovery was delayed after SIRT6 silencing by injected shRNA lentivirus into the crushed sciatic nerve, which exhibited a reduced expression of myelin-related proteins (e.g., MAG and MBP), severer myoatrophy of target muscles, and inferior nerve conduction compared to the shRNA control injected mice. In vitro, we found that SIRT6 inhibition by being treated with a selective inhibitor OSS_128167 or lentivirus transfection impairs migration and phagocytosis capacity of bone marrow-derived macrophages (BMDM). In addition, SIRT6 expression was discovered to be reduced after M1 polarization, but SIRT6 was enhanced after M2 polarization in the monocyte-macrophage cell line RAW264.7 and BMDM. Moreover, SIRT6 inhibition increased M1 macrophage polarization with a concomitant decrease in M2 polarization both in RAW264.7 and BMDM via activating NF-κB and TNF-α expression, and SIRT6 activation by UBCS039 treatment could shift the macrophages from M1 to M2 phenotype. Conclusion Our findings indicate that SIRT6 inhibition impairs peripheral nerve repair through suppressing the migration, phagocytosis, and M2 polarization of macrophages. Therefore, SIRT6 may become a favorable therapeutic target for peripheral nerve injury.

In vitro, In vivo and Ex vivo Models for Peripheral Nerve Injury and Regeneration

2021 ◽  
Vol 19 ◽  
Author(s):  
Andrew Li ◽  
Clifford Pereira ◽  
Elise Eleanor Hill ◽  
Olivia Vukcevich ◽  
Aijun Wang
Keyword(s):  
Peripheral Nerve ◽  
Peripheral Nerve Injury ◽  
Ex Vivo ◽  
Peripheral Nerve Regeneration ◽  
Therapeutic Interventions ◽  
Peripheral Nerve Injuries ◽  
Traumatic Injuries ◽  
And Function

: Peripheral nerve injuries (PNI) frequently occur secondary to traumatic injuries. Recovery from these injuries can be expectedly poor, especially in proximal injuries. In order to study and improve peripheral nerve regeneration, scientists rely on peripheral nerve models to identify and test therapeutic interventions. In this review, we discuss the best described and most commonly used peripheral nerve models that scientists have and continue to use to study peripheral nerve physiology and function.

scholarly journals In Vivo Nerve-Macrophage Interactions Following Peripheral Nerve Injury

2012 ◽  
Vol 32 (11) ◽  
pp. 3898-3909 ◽  
Author(s):  
A. F. Rosenberg ◽  
M. A. Wolman ◽  
C. Franzini-Armstrong ◽  
M. Granato
Keyword(s):  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury

scholarly journals Presence and activation of pro-inflammatory macrophages are associated with CRYAB expression in vitro and after peripheral nerve injury

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Erin-Mai F. Lim ◽  
Vahid Hoghooghi ◽  
Kathleen M. Hagen ◽  
Kunal Kapoor ◽  
Ariana Frederick ◽  
...  
Keyword(s):  
Sciatic Nerve ◽  
Peripheral Nerve ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Sciatic Nerve Crush ◽  
Nerve Crush ◽  
Cytokines And Chemokines ◽  
Inflammatory Macrophages ◽  
Nerve Crush Injury

Abstract Background Inflammation constitutes both positive and negative aspects to recovery following peripheral nerve injury. Following damage to the peripheral nervous system (PNS), immune cells such as macrophages play a beneficial role in creating a supportive environment for regrowing axons by phagocytosing myelin and axonal debris. However, a prolonged inflammatory response after peripheral nerve injury has been implicated in the pathogenesis of negative symptoms like neuropathic pain. Therefore, the post-injury inflammation must be carefully controlled to prevent secondary damage while allowing for regeneration. CRYAB (also known as alphaB-crystallin/HSPB5) is a small heat shock protein that has many protective functions including an immunomodulatory role in mouse models of multiple sclerosis, spinal cord injury, and stroke. Because its expression wanes and rebounds in the early and late periods respectively after PNS damage, and CRYAB null mice with sciatic nerve crush injury display symptoms of pain, we investigated whether CRYAB is involved in the immune response following PNS injury. Methods Sciatic nerve crush injuries were performed in age-matched Cryab knockout (Cryab−/−) and wildtype (WT) female mice. Nerve segments distal to the injury site were processed by immunohistochemistry for macrophages and myelin while protein lysates of the nerves were analyzed for cytokines and chemokines using Luminex and enzyme-linked immunosorbent assay (ELISA). Peritoneal macrophages from the two genotypes were also cultured and polarized into pro-inflammatory or anti-inflammatory phenotypes where their supernatants were analyzed for cytokines and chemokines by ELISA and protein lysates for macrophage antigen presenting markers using western blotting. Results We report that (1) more pro-inflammatory CD16/32+ macrophages are present in the nerves of Cryab−/− mice at days 14 and 21 after sciatic nerve crush-injury compared to WT counterparts, and (2) CRYAB has an immunosuppressive effect on cytokine secretion [interleukin (IL)-β, IL-6, IL-12p40, tumor necrosis factor (TNF)-α] from pro-inflammatory macrophages in vitro. Conclusions CRYAB may play a role in curbing the potentially detrimental pro-inflammatory macrophage response during the late stages of peripheral nerve regeneration.

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