IntroductionA 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 functional evaluation of nerve regeneration and simultaneously add to better interstudy comparability.MethodsThe aims of the present paper are threefold: (1) to describe the functional method of CatWalk gait analysis, (2) to characterize different parameters acquired by CatWalk gait analysis, and to find the most frequently used parameters as well as (3) to compare their reliability and validity throughout the different studies.ResultsIn the reviewed articles, the most frequently used parameters were Swing Duration (30), Print Size (27), Stride Length (26), and Max Contact Area (24). Swing Duration was not only frequently used but was also the most reliable and valid parameter. Therefore, we hypothesize that Swing Duration constitutes an important parameter to be chosen for future studies, as it has the highest level of reliability and validity.ConclusionIn conclusion, CatWalk can be used as a complementary approach to other behavioral testing paradigms to assess clinically relevant behavioral benefits, with the main advantage that this system demonstrates both static and dynamic gait parameters at the same time. Due to limited reliability and validity of certain parameters, we recommend that only the most frequently assessed parameters should be used in the future.
Tissue engineering is a popular topic in peripheral nerve repair. Combining a nerve conduit with supporting adipose-derived cells could offer an opportunity to prevent time-consuming Schwann cell culture or the use of an autograft with its donor site morbidity and eventually improve clinical outcome. The aim of this study was to provide a broad overview over promising transplantable cells under equal experimental conditions over a long-term period. A 10-mm gap in the sciatic nerve of female Sprague-Dawley rats (7 groups of 7 animals, 8 weeks old) was bridged through a biodegradable fibrin conduit filled with rat adipose-derived stem cells (rASCs), differentiated rASCs (drASCs), human (h)ASCs from the superficial and deep abdominal layer, human stromal vascular fraction (SVF), or rat Schwann cells, respectively. As a control, we resutured a nerve segment as an autograft. Long-term evaluation was carried out after 12 weeks comprising walking track, morphometric, and MRI analyses. The sciatic functional index was calculated. Cross sections of the nerve, proximal, distal, and in between the two sutures, were analyzed for re-/myelination and axon count. Gastrocnemius muscle weights were compared. MRI proved biodegradation of the conduit. Differentiated rat ASCs performed significantly better than undifferentiated rASCs with less muscle atrophy and superior functional results. Superficial hASCs supported regeneration better than deep hASCs, in line with published in vitro data. The best regeneration potential was achieved by the drASC group when compared with other adipose tissue-derived cells. Considering the ease of procedure from harvesting to transplanting, we conclude that comparison of promising cells for nerve regeneration revealed that particularly differentiated ASCs could be a clinically translatable route toward new methods to enhance peripheral nerve repair.
Traumatic nerve injuries are a major clinical challenge. Tissue engineering using a combination of nerve conduits and cell-based therapies represents a promising approach to nerve repair. The aim of this study was to examine the regeneration potential of human adipose-derived stem cells (hASCs) after transplantation in a nonautogenous setting and to compare them with autogenous rat ASCs (rASCs) for early peripheral nerve regeneration. Furthermore, the use of MRI to assess the continuous process of nerve regeneration was elaborated. The sciatic nerve injury model in female Sprague-Dawley rats was applied, and a 10-mm gap created by using a fibrin conduit seeded with the following cell types: rASCs, Schwann cell (SC)-like cells from rASC, rat SCs (rSCs), hASCs from the superficial and deep abdominal layer, as well as human stromal vascular fraction (1 × 10(6) cells). As a negative control group, culture medium only was used. After 2 weeks, nerve regeneration was assessed by immunocytochemistry. Furthermore, MRI was performed after 2 and 4 weeks to monitor nerve regeneration. Autogenous ASCs and SC-like cells led to accelerated peripheral nerve regeneration, whereas the human stem cell groups displayed inferior results. Nevertheless, positive trends could be observed for hASCs from the deep abdominal layer. By using a clinical 3T MRI scanner, we were able to visualize the graft as a small black outline and small hyperintensity indicating the regenerating axon front. Furthermore, a strong correlation was found between the length of the regenerating axon front measured by MRI and the length measured by immunocytochemistry (r = 0.74, p = 0.09). We successfully transplanted and compared human and autologous stem cells for peripheral nerve regeneration in a rat sciatic nerve injury model. Furthermore, we were able to implement the clinical 3T MRI scanner to monitor the efficacy of cellular therapy over time.
The therapeutic potential of adult stem cells may become a relevant option in clinical care in the future. In hand and plastic surgery, cell therapy might be used to enhance nerve regeneration and help surgeons and clinicians to repair debilitating nerve injuries. Adipose-derived stem cells (ASCs) are found in abundant quantities and can be harvested with a low morbidity. In order to define the optimal fat harvest location and detect any potential differences in ASC proliferation properties, we compared biopsies from different anatomical sites (inguinal, flank, pericardiac, omentum, neck) in Sprague-Dawley rats. ASCs were expanded from each biopsy and a proliferation assay using different mitogenic factors, basic fibroblast growth factor (bFGF) and platelet-derived growth factor (PDGF) was performed. Our results show that when compared with the pericardiac region, cells isolated from the inguinal, flank, omental and neck regions grow significantly better in growth medium alone. bFGF significantly enhanced the growth rate of ASCs isolated from all regions except the omentum. PDGF had minimal effect on ASC proliferation rate but increases the growth of ASCs from the neck region. Analysis of all the data suggests that ASCs from the neck region may be the ideal stem cell sources for tissue engineering approaches for the regeneration of nervous tissue.
The nervous system plays a key role in controlling the dynamic functions of multicellular complex organisms. Although peripheral nerves are supposed to play a pivotal role in tumor growth and dissemination, little experimental evidence exists to date. We assessed the effect of denervation on breast cancer growth by magnetic resonance imaging (MRI) in rats. Human breast cancer cells were implanted into adipofascial flaps with intact or surgically excised supplying nerve. Tumor volumes were measured 2 and 8 weeks after implantation by in vivo MRI. Results were validated by histology. Postoperative tumor volumes at 2 and 8 weeks were reduced by 76% (95% CI: 22-93%) in the denervated groups. Tumor area as determined histologically was reduced by 70% (95% CI: 60-78%). Thus, peripheral denervation may be an effective surgical approach for the palliative treatment of locally progressing or uncontrollable breast cancer.
If utilized on an intact nerve, intramuscular injection may lead to inferior results. If the nerve was cut or treated with BTX; however, intramuscular injection tends to be superior. These findings may prove interesting for future studies and eventual clinical application.
BackgroundThe aim was to evaluate the regenerative effect of epineural injection of rat ASCs (rASCs) in three different settings of acute and chronic compression in a rat sciatic nerve model.MethodsAcute compression (60 s) with a vessel clamp over a distance of 1 mm (group 1) or 10 mm (group 2), as well as chronic compression with a permanent remaining, nonabsorbable polymeric clip over a distance of 1 mm (group 3) was performed. Depending on the group, either 5 × 106 rASCs or the same volume (25 μl) of culture medium (CM) was injected with a 30G needle in the epineurium at the time of compression. Outcome measures were functional gait evaluations, imaging analysis, histomorphometric analyses, and muscle weight.ResultsThe rats in group 2 had a better function than those with group 1 at one and especially at 2 weeks. After 4 weeks however, almost all rats were close to a normal function. There was a similar Muscle Weight Ratio (MWR) after 2 weeks in all groups, whereas after 4 weeks, the MWR in group 3 was lower compared with group 1 and 2. Histomorphometric analysis showed a better myelination in group 1 & 2 compared to group 3 after 4 weeks. ASCs have a beneficial effect on myelin thickness (G‐Ratio).ConclusionsWe successfully evaluated the regenerative effect of epineural injection of rASCs in three different settings of acute and chronic compression. However, there were no significant differences in outcomes between the ASC‐treated groups and control groups.
confirmed. The patient's vision loss and eye movements improved after the operation (Fig. 1C). In the examination, the light reflex was completely natural. DISCUSSIONOnodi cell, which is a type of ethmoid cells, is seen in routine radiological imaging at 8% to 14% and in cadaver studies up to 60%. 8,9 Its close proximity to the orbital apex increases the clinical importance of the lesions of this area. Onodi cell mucocele has been shown extremely rarely in the literature. Mucocele actually arises with decreased sinus drainage. It is a slow growing, mucus containing cystic lesion in benign nature. Clinically, it is generally asymptomatic but it may present with various compression findings depending on the location. 6,10 Direct mass compression effect was shown primarily in the pathogenesis of optic neuropathy for onodi cell mucocele. Apart from this, superinfection and ischemia, which develop as a result of compression of the vasa nervorum, are among other causes. Response to treatment is good even in patients without infection and inflammation.Radiological imaging methods play an important role in the diagnosis of mucocele, since the lesion has no specific clinical and laboratory findings. This importance increases even more in patients presenting with compression symptoms. With imaging, the diagnosis of mucocele is easily made and it is a guide for the necessary surgical procedure. The onodi cell mucocele shows the cystic enlargement structure typically found in the upper lateral of the sphenoid sinus. It can be monitored at different intensity and density due to the amount of protein in the mucus content and secondary infections. Although post-contrast imaging shows peripheral minimal enhancement, it is not usually contrasted. While CT is good at showing the expansion in the bony structure, MR clearly reveals the relationship with neighboring structures. The treatment is surgical resection with an endoscopic approach. 7,11 In conclusion, as we have shown in our case, onodi cell mucocele is a rare cause of sudden vision loss. Imaging methods are essential for early diagnosis and promptly treatment, so patients' symptoms can be reversible.
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