Peripheral nerve injury results in loss of motor and sensory function distal to the nerve injury and is often permanent in nerve gaps longer than 5 cm. Autologous nerve grafts (nerve autografts) ...utilize patients' own nerve tissue from another part of their body to repair the defect and are the gold standard in care. However, there is a limited autologous tissue supply, size mismatch between donor nerve and injured nerve, and morbidity at the site of nerve donation. Decellularized cadaveric nerve tissue alleviates some of these limitations and has demonstrated success clinically. We previously developed an alternative apoptosis-assisted decellularization process for nerve tissue. This new process may result in an ideal scaffold for peripheral nerve regeneration by gently removing cells and antigens while preserving delicate topographical cues. In addition, the apoptosis-assisted process requires less active processing time and is inexpensive. This study examines the utility of apoptosis-decellularized peripheral nerve scaffolds compared to detergent-decellularized peripheral nerve scaffolds and isograft controls in a rat nerve gap model. Results indicate that, at 8 weeks post-injury, apoptosis-decellularized peripheral nerve scaffolds perform similarly to detergent-decellularized and isograft controls in both functional (muscle weight recovery, gait analysis) and histological measures (neurofilament staining, macrophage infiltration). These new apoptosis-decellularized scaffolds hold great promise to provide a less expensive scaffold for nerve injury repair, with the potential to improve nerve regeneration and functional outcomes compared to current detergent-decellularized scaffolds.
Locomotive changes are often associated with disease or injury, and these changes can be quantified through gait analysis. Gait analysis has been applied to preclinical studies, providing ...quantitative behavioural assessment with a reasonable clinical analogue. However, available gait analysis technology for small animals is somewhat limited. Furthermore, technological and analytical challenges can limit the effectiveness of preclinical gait analysis. The Gait Analysis Instrumentation and Technology Optimized for Rodents (GAITOR) Suite is designed to increase the accessibility of preclinical gait analysis to researchers, facilitating hardware and software customization for broad applications. Here, the GAITOR Suite's utility is demonstrated in 4 models: a monoiodoacetate (MIA) injection model of joint pain, a sciatic nerve injury model, an elbow joint contracture model, and a spinal cord injury model. The GAITOR Suite identified unique compensatory gait patterns in each model, demonstrating the software's utility for detecting gait changes in rodent models of highly disparate injuries and diseases. Robust gait analysis may improve preclinical model selection, disease sequelae assessment, and evaluation of potential therapeutics. Our group has provided the GAITOR Suite as an open resource to the research community at www.GAITOR.org , aiming to promote and improve the implementation of gait analysis in preclinical rodent models.
Chronic low back pain is a global socioeconomic crisis and treatments are lacking in part due to inadequate models. Etiological research suggests that the predominant pathology associated with ...chronic low back pain is intervertebral disc degeneration. Various research teams have created rat models of disc degeneration, but the clinical translatability of these models has been limited by an absence of robust chronic pain‐like behavior. To address this deficit, disc degeneration was induced via an artificial annular tear in female Sprague Dawley rats. The subsequent degeneration, which was allowed to progress for 18‐weeks, caused a drastic reduction in disc volume. Furthermore, from week 10 till study conclusion, injured animals exhibited significant axial hypersensitivity. At study end, intervertebral discs were assessed for important characteristics of human degenerated discs: extracellular matrix breakdown, hypocellularity, inflammation, and nerve sprouting. All these aspects were significantly increased in injured animals compared to sham controls. Also of note, 20 significant correlations were detected between selected outcomes including a moderate and highly significant correlation (R = 0.59, p < 0.0004) between axial hypersensitivity and disc nerve sprouting. These data support this model as a rigorous platform to explore the pathobiology of disc‐associated low back pain and to screen treatments.
This work delineates a novel model of disc degeneration with disc‐associated pain‐like behavior in female Sprague Dawley rats. The data herein provides valuable information for basic science researchers concerning the pathobiology underpinning disc‐associated nociception and constitutes a platform for evaluating therapeutics.
Introduction
Oxidative stress due to excess reactive oxygen species (ROS) is related to many chronic illnesses including degenerative disc disease and osteoarthritis. MnTnBuOE-2-PyP
5+
(BuOE), a ...manganese porphyrin analog, is a synthetic superoxide dismutase mimetic that scavenges ROS and has established good treatment efficacy at preventing radiation-induced oxidative damage in healthy cells. BuOE has not been studied in degenerative disc disease applications and only few studies have loaded BuOE into drug delivery systems. The goal of this work is to engineer BuOE microparticles (MPs) as an injectable therapeutic for long-term ROS scavenging.
Methods
Methacrylated chondroitin sulfate-A MPs (vehicle) and BuOE MPs were synthesized
via
water-in-oil polymerization and the size, surface morphology, encapsulation efficiency and release profile were characterized. To assess long term ROS scavenging of BuOE MPs, superoxide scavenging activity was evaluated over an 84-day time course.
In vitro
cytocompatibility and cellular uptake were assessed on human intervertebral disc cells.
Results
BuOE MPs were successfully encapsulated in MACS-A MPs and exhibited a slow-release profile over 84 days. BuOE maintained high potency in superoxide scavenging after encapsulation and after 84 days of incubation at 37 °C as compared to naked BuOE. Vehicle and BuOE MPs (100
µ
g/mL) were non-cytotoxic on nucleus pulposus cells and MPs up to 23
µ
m were endocytosed.
Conclusions
BuOE MPs can be successfully fabricated and maintain potent superoxide scavenging capabilities up to 84-days.
In vitro
assessment reveals the vehicle and BuOE MPs are not cytotoxic and can be taken up by cells.
Background
Chronic low back pain (LBP) is a leading cause of disability, but treatments for LBP are limited. Degeneration of the intervertebral disc due to loss of neuroinhibitory sulfated ...glycosaminoglycans (sGAGs) allows nerves from dorsal root ganglia to grow into the core of the disc. Treatment with a decellularized tissue hydrogel that contains sGAGs may inhibit nerve growth and prevent disc‐associated LBP.
Methods
A protocol to decellularize porcine nucleus pulposus (NP) was adapted from previous methods. DNA, sGAG, α‐gal antigen, and collagen content were analyzed before and after decellularization. The decellularized tissue was then enzymatically modified to be injectable and form a gel at 37°C. Following this, the mechanical properties, microstructure, cytotoxicity, and neuroinhibitory properties were analyzed.
Results
The decellularization process removed 99% of DNA and maintained 74% of sGAGs and 154% of collagen compared to the controls NPs. Rheology demonstrated that regelled NP exhibited properties similar to but slightly lower than collagen‐matched controls. Culture of NP cells in the regelled NP demonstrated an increase in metabolic activity and DNA content over 7 days. The collagen content of the regelled NP stayed relatively constant over 7 days. Analysis of the neuroinhibitory properties demonstrated regelled NP significantly inhibited neuronal growth compared to collagen controls.
Conclusions
The decellularization process developed here for porcine NP tissue was able to remove the antigenic material while maintaining the sGAG and collagen. This decellularized tissue was then able to be modified into a thermally forming gel that maintained the viability of cells and demonstrated robust neuroinhibitory properties in vitro. This biomaterial holds promise as an NP supplement to prevent nerve growth into the native disc and NP in vivo.
A whole porcine nucleus pulposus decellularization method was optimized. The decellularized tissue was used to create a thermally forming gel that maintained nucleus pulposus cell viability and inhibited dorsal root ganglion neurite growth.
Chronic low back pain (LBP) is a global socioeconomic crisis. Etiological research suggests the predominant pathology associated with chronic LBP is disc degeneration. The disc is a composed of a ...cartilaginous end plate, nucleus pulposus, and annulus fibrosus. The disc is predominantly avascular and aneural, predisposing it to degeneration. Disc degeneration in humans can be diagnosed using X-ray imaging and quantified using a measurement known as disc height index (DHI). DHI is also the current gold standard for evaluating disc degeneration in animal models. Unfortunately, X-ray imaging suffers poor spatial resolution, limiting the precision of DHI in rodents. Further, the application of disc height as a surrogate for degeneration involves subjective choices by experimenters, decreasing reliability. Microcomputed tomography (µCT) generates 3D reconstructions with profound spatial resolution. µCT has been used to measure disc degeneration, however, this work used costly contrast agents that increase procedure time. The objective of this work was to create a novel method for using µCT to assess disc degeneration in real-time, non-invasively and without contrast agents. Herein we describe a method for quantifying disc volume in vivo using µCT and the data suggest that this metric is precise, reliable, and sensitive to disc degeneration.
Congenital heart disease (CHD) affects almost one percent of all live births. Despite diagnostic and surgical reparative advances, the causes and mechanisms of CHD are still primarily unknown. The ...extracellular matrix plays a large role in cell communication, function, and differentiation, and therefore likely plays a role in disease development and pathophysiology. Cell adhesion and gap junction proteins, such as integrins and connexins, are also essential to cellular communication and behavior, and could interact directly (integrins) or indirectly (connexins) with the extracellular matrix. In this work, we explore disparities in the expression and spatial patterning of extracellular matrix, adhesion, and gap junction proteins between wild type and
mutant mice. Decellularization and proteomic analysis, Western blotting, histology, immunostaining, and mechanical assessment of embryonic and neonatal wild type and
mutant mouse hearts were performed. An increased abundance of collagen IV, fibronectin, and integrin β-1 was found in
mutant neonatal mouse hearts, as well as increased expression of connexin 43 in embryonic mutant hearts. Furthermore, a ventricular noncompaction phenotype was observed in both embryonic and neonatal mutant hearts, as well as spatial disorganization of ECM proteins collagen IV and laminin in mutant hearts. Characterizing such properties in a mutant mouse model provides valuable information that can be applied to better understanding the mechanisms of congenital heart disease.
PDF
