The diagnosis of Parkinson’s disease (PD) and atypical parkinsonian syndromes is difficult due to the lack of reliable, easily accessible biomarkers. Multiple system atrophy (MSA) is a synucleinopathy whose symptoms often overlap with PD. Exosomes isolated from blood by immunoprecipitation using CNS markers provide a window into the brain’s biochemistry and may assist in distinguishing between PD and MSA. Thus, we asked whether α-synuclein (α-syn) in such exosomes could distinguish among healthy individuals, patients with PD, and patients with MSA. We isolated exosomes from the serum or plasma of these three groups by immunoprecipitation using neuronal and oligodendroglial markers in two independent cohorts and measured α-syn in these exosomes using an electrochemiluminescence ELISA. In both cohorts, α-syn concentrations were significantly lower in the control group and significantly higher in the MSA group compared to the PD group. The ratio between α-syn concentrations in putative oligodendroglial exosomes compared to putative neuronal exosomes was a particularly sensitive biomarker for distinguishing between PD and MSA. Combining this ratio with the α-syn concentration itself and the total exosome concentration, a multinomial logistic model trained on the discovery cohort separated PD from MSA with an AUC = 0.902, corresponding to 89.8% sensitivity and 86.0% specificity when applied to the independent validation cohort. The data demonstrate that a minimally invasive blood test measuring α-syn in blood exosomes immunoprecipitated using CNS markers can distinguish between patients with PD and patients with MSA with high sensitivity and specificity. Future optimization and validation of the data by other groups would allow this strategy to become a viable diagnostic test for synucleinopathies.

Basic fibroblast growth factor (bFGF) plays a crucial role in diverse cellular functions from wound healing to bone regeneration. However, a major obstacle to the widespread application of bFGF is its inherent instability during storage and delivery. Herein, we describe stabilization of bFGF by covalent conjugation of a heparin-mimicking polymer, a copolymer consisting of styrene sulfonate units and methyl methacrylate units bearing poly(ethylene glycol) side chains. The bFGF conjugate of this polymer retained bioactivity after synthesis and was stable to a variety of environmentally and therapeutically relevant stressors such as heat, mild and harsh acidic conditions, storage, and proteolytic degradation, compared to native bFGF. After applied stress, the conjugate was also significantly more active than the control conjugate system where the styrene sulfonate units were omitted from the polymer structure. This research has important implications for the clinical use of bFGF and for stabilization of heparin-binding growth factors in general.

Here we present a photodegradable hydrogel as a biocompatible, nonfouling photoresist capable of presenting positive and negative features through single-photon and two-photon degradation. An ortho-nitrobenzylether (o-NBE) moiety is used as a polymerizable cap for poly(ethylene glycol) chains to create a photodegradable macromer. Positive and negative features can be patterned into/onto a hydrogel over a broad range of length scales (∼10−7 to 10−2 m (nm−cm)) in single- and two-photon photolysis. Phase contrast micrographs and profilometry data show that a partially degradable hydrogel network undergoes swelling to produce positive features with varying size (10−100 μm). Conjugation of a coumarin fluorophore to the o-NBE macromer enhances the sensitivity of the hydrogel to two-photon degradation, simultaneously incorporating fluorescence visualization with no added dye.

Biomaterial scaffold architecture has not been investigated as a tunable source of influence on spinal cord regeneration. This study compared regeneration in a transected spinal cord within various designed-macro-architecture scaffolds to determine if these architectures alone could enhance regeneration. Three-dimensional (3-D) designs were created and molds were built on a 3-D printer. Salt-leached porous poly(epsilon-caprolactone) was cast in five different macro-architectures: cylinder, tube, channel, open-path with core, and open-path without core. The two open-path designs were created in this experiment to compare different supportive aspects of architecture provided by scaffolds and their influence on regeneration. Rats received T8 transections and implanted scaffolds for 1 and 3 months. Overall morphology and orientation of sections were characterized by H&E, luxol fast blue, and cresyl violet staining. Borders between intact gray matter and non-regenerated defect were observed from GFAP immunolabeling. Nerve fibers and regenerating axons were identified with Tuj-1 immunolabeling. The open-path designs allowed extension of myelinated fibers along the length of the defect both exterior to and inside the scaffolds and maintained their original defect length up to 3 months. In contrast, the cylinder, tube, and channel implants had a doubling of defect length from secondary damage and large scar and cyst formation with no neural tissue bridging. The open-path scaffold architectures enhanced spinal cord regeneration compared to the three other designs without the use of biological factors.

Light is a non-invasive tool that is widely used in a range of biomedical applications. Techniques such as photopolymerization, photodegradation, and photouncaging can be used to alter the chemical and physical properties of biomaterials in the presence of live cells. Long-wave UV light (315 nm–400 nm) is an easily accessible and commonly used energy source for triggering biomaterial changes. Although exposure to low doses of long-wave UV light is generally accepted as biocompatible, most studies employing this wavelength only establish cell viability, ignoring other possible (non-toxic) effects. Since light exposure of wavelengths longer than 315 nm may potentially induce changes in cell behavior, we examined changes in gene expression of human mesenchymal stem cells exposed to light under both 2D and 3D culture conditions, including two different hydrogel fabrication techniques, decoupling UV exposure and radical generation. While exposure to long-wave UV light did not induce significant changes in gene expression regardless of culture conditions, significant changes were observed due to scaffold fabrication chemistry and between cells plated in 2D versus encapsulated in 3D scaffolds. In order to facilitate others in searching for more specific changes between the many conditions, the full data set is available on Gene Expression Omnibus for querying.

This study evaluated the response of rat brain to 2 degradable polymers (poly (L-lactic-co-glycolic acid) (PLGA), and poly(epsilon-caprolactone) (PCL)), two common materials in tissue engineering. PLGA has been extensively studied in the brain for controlled drug release as injectable microspheres and is generally accepted as biocompatible in that capacity. Biocompatibility in other forms and for different functions in the brain has not been widely studied. PCL was chosen as an alternative to PLGA for its slower degradation and less-acidic pH upon degradation. Porous scaffolds were made from both polymers and implanted into rat cerebral cortex for 1 and 4 weeks. Morphology, defect size, activation of microglia (OX-42) and astrocytes (glial fibrillary acidic protein (GFAP)), infiltration of activated macrophages (major histocompatibility complex (MHC)-II), and ingrowth of neurons (beta-tubulin type III (Tuj-1)) and progenitor cells (nestin) were analyzed using hematoxylin and eosin staining and immunofluorescence. PCL induced a lower inflammatory response than PLGA, as demonstrated by lower MHC-II and GFAP expression and greater ingrowth. Both polymers alleviated astrocytic activation and prevented enlargement of the defect. Tuj-1-, nestin-, and GFAP-positive cells were observed growing on both polymers at the peripheries of the sponge implants, demonstrating their permissiveness to neural ingrowth. These findings suggest that both polymers attenuate secondary death and scarring and that PCL might have advantages over PLGA.

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ObjectiveWe evaluated the prevalence of pathogenic repeat expansions in replication factor C subunit 1 (RFC1) and disabled adaptor protein 1 (DAB1) in an undiagnosed ataxia cohort from North America.MethodsA cohort of 596 predominantly adult-onset patients with undiagnosed familial or sporadic cerebellar ataxia was evaluated at a tertiary referral ataxia center and excluded for common genetic causes of cerebellar ataxia. Patients were then screened for the presence of pathogenic repeat expansions in RFC1 (AAGGG) and DAB1 (ATTTC) using fluorescent repeat-primed PCR (RP-PCR). Two additional undiagnosed ataxia cohorts from different centers, totaling 302 and 13 patients, respectively, were subsequently screened for RFC1, resulting in a combined 911 subjects tested.ResultsIn the initial cohort, 41 samples were identified with 1 expanded allele in the RFC1 gene (6.9%), and 9 had 2 expanded alleles (1.5%). For the additional cohorts, we found 20 heterozygous samples (6.6%) and 17 biallelic samples (5.6%) in the larger cohort and 1 heterozygous sample (7.7%) and 3 biallelic samples (23%) in the second. In total, 29 patients were identified with biallelic repeat expansions in RFC1 (3.2%). Of these 29 patients, 8 (28%) had a clinical diagnosis of cerebellar ataxia, neuropathy, and vestibular areflexia syndrome (CANVAS), 14 had cerebellar ataxia with neuropathy (48%), 4 had pure cerebellar ataxia (14%), and 3 had spinocerebellar ataxia (10%). No patients were identified with expansions in the DAB1 gene (spinocerebellar ataxia type 37).ConclusionsIn a large undiagnosed ataxia cohort from North America, biallelic pathogenic repeat expansion in RFC1 was observed in 3.2%. Testing should be strongly considered in patients with ataxia, especially those with CANVAS or neuropathy.