Intrathecal triamcinolone acetonide exerts anti-inflammatory effects on Lewis rat experimental autoimmune neuritis and direct anti-oxidative effects on Schwann cells

Prophylactic effect of chronic immunosuppression in a mouse model of CSF-1 receptor-related leukoencephalopathy

Mutations leading to colony-stimulating factor-1 receptor (CSF-1R) loss-of-function or haploinsufficiency cause CSF1R-related leukoencephalopathy (CRL), an adult-onset disease characterized by loss of myelin and neurodegeneration, for which there is no effective therapy. Symptom onset usually occurs in the fourth decade of life and the penetrance of disease in carriers is high. However, familial studies have identified a few carriers of pathogenic CSF1R mutations that remain asymptomatic even in their seventh decade of life, raising the possibility that the development and severity of disease might be influenced by environmental factors. Here we report new cases in which long-term glucocorticoid treatment is associated with asymptomatic status in elder carriers of pathogenic CSF-1R mutations. The main objective of the present study was to investigate the link between chronic immunosuppression initiated pre-symptomatically and resistance to the development of symptomatic CRL, in the Csf1r+/- mouse model. We show that chronic prednisone administration prevents the development of memory, motor coordination and social interaction deficits, as well as the demyelination, neurodegeneration and microgliosis associated with these deficits. These findings are in agreement with the preliminary clinical observations and support the concept that pre-symptomatic immunosuppression is protective in patients carrying pathogenic CSF1R variants associated with CRL. Proteomic analysis of microglia and oligodendrocytes indicates that prednisone suppresses processes involved in microglial activation and alleviates senescence and improves fitness of oligodendrocytes. This analysis also identifies new potential targets for therapeutic intervention.

Development and validation of a simple method for the determination of triamcinolone acetonide in nasal spray

A rapid, convenient, and sensitive analytical technique for quantitative analysis of triamcinolone acetonide (TAC) in pharmaceutical nasal spray dosage form using the blue tetrazolium colorimetric reaction and UV spectrophotometric method was developed and validated. Beer's law of the developed method was proven in the concentration range of 10-40 µg/mL and showed a specific linear relationship with coefficient value R2 = 0.998. The LOQ level was 9.99 µg/mL, with (RSD = 0.26%). From precision assay, RSD values have been obtained for the repeatability and intermediate precision, which were found to be (RSD = 1.65%) and (RSD = 2.01%), respectively, indicating that the method is reproducible. Recovery studies showed mean recoveries in the range of (100.08-103.65 %), meeting the acceptance criteria for accuracy. In addition, we compared the results of the developed method UV-Vis spectrophotometric procedure with those of a well-established official USP analytical procedure (HPLC), and the results showed good agreement. The proposed UV method represents a potential alternative to the official USP analytical assay procedure (HPLC) for estimating TAC in nasal spray forms. Furthermore, it has the potential to be implemented in routine use for rapid qualitative and quantitative determinations for TAC.

Propionate exerts neuroprotective and neuroregenerative effects in the peripheral nervous system

In inflammatory neuropathies, oxidative stress results in neuronal and Schwann cell (SC) death promoting early neurodegeneration and clinical disability. Treatment with the short-chain fatty acid propionate showed a significant immunoregulatory and neuroprotective effect in multiple sclerosis patients. Similar effects have been described for patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Therefore, Schwann cell's survival and dorsal root ganglia (DRG) outgrowth were evaluated in vitro after propionate treatment and application of H2O2 or S-nitroso-N-acetyl-D-L-penicillamine (SNAP) to evaluate neuroprotection. In addition, DRG resistance was evaluated by the application of oxidative stress by SNAP ex vivo after in vivo propionate treatment. Propionate treatment secondary to SNAP application on DRG served as a neuroregeneration model. Histone acetylation as well as expression of the free fatty acid receptor (FFAR) 2 and 3, histone deacetylases, neuroregeneration markers, and antioxidative mediators were investigated. β-hydroxybutyrate was used as a second FFAR3 ligand, and pertussis toxin was used as an FFAR3 antagonist. FFAR3, but not FFAR2, expression was evident on SC and DRG. Propionate-mediated activation of FFAR3 and histone 3 hyperacetylation resulted in increased catalase expression and increased resistance to oxidative stress. In addition, propionate treatment resulted in enhanced neuroregeneration with concomitant growth-associated protein 43 expression. We were able to demonstrate an antioxidative and neuroregenerative effect of propionate on SC and DRG mediated by FFAR3-induced histone acetylases expression. Our results describe a pathway to achieve neuroprotection/neuroregeneration relevant for patients with immune-mediated neuropathies.

Selection of an Appropriate In Vitro Susceptibility Test for Assessing Anti-Pythium insidiosum Activity of Potassium Iodide, Triamcinolone Acetonide, Dimethyl Sulfoxide, and Ethanol

The orphan but highly virulent pathogen Pythium insidiosum causes pythiosis in humans and animals. Surgery is a primary treatment aiming to cure but trading off losing affected organs. Antimicrobial drugs show limited efficacy in treating pythiosis. Alternative drugs effective against the pathogen are needed. In-house drug susceptibility tests (i.e., broth dilution, disc diffusion, and radial growth assays) have been established, some of which adapted the standard protocols (i.e., CLSI M38-A2 and CLSI M51) designed for fungi. Hyphal plug, hyphal suspension, and zoospore are inocula commonly used in the drug susceptibility assessment for P. insidiosum. A side-by-side comparison demonstrated that each method had advantages and limitations. Minimum inhibitory and cidal concentrations of a drug varied depending on the selected method. Material availability, user experience, and organism and drug quantities determined which susceptibility assay should be used. We employed the hyphal plug and a combination of broth dilution and radial growth methods to screen and validate the anti-P. insidiosum activities of several previously reported chemicals, including potassium iodide, triamcinolone acetonide, dimethyl sulfoxide, and ethanol, in which data on their anti-P. insidiosum efficacy are limited. We tested each chemical against 29 genetically diverse isolates of P. insidiosum. These chemicals possessed direct antimicrobial effects on the growth of the pathogen in a dose- and time-dependent manner, suggesting their potential application in pythiosis treatment. Future attempts should focus on standardizing these drug susceptibility methods, such as determining susceptibility/resistant breakpoints, so healthcare workers can confidently interpret a result and select an effective drug against P. insidiosum.

Expression and Clinical Correlation Analysis Between Repulsive Guidance Molecule a and Neuromyelitis Optica Spectrum Disorders

Objectives

This study sought to explore the expression patterns of repulsive guidance molecules a (RGMa) in neuromyelitis optica spectrum disorders (NMOSD) and to explore the correlation between RGMa and the clinical features of NMOSD.

Methods

A total of 83 NMOSD patients and 22 age-matched healthy controls (HCs) were enrolled in the study from October 2017 to November 2021. Clinical parameters, including Expanded Disability Status Scale (EDSS) score, degree of MRI enhancement, and AQP4 titer were collected. The expression of serum RGMa was measured by enzyme-linked immunosorbent assay (ELISA) and compared across the four patient groups. The correlation between serum RGMa levels and different clinical parameters was also assessed.

Results

The average serum expression of RGMa in the NMOSD group was significantly higher than that in the HC group (p < 0.001). Among the patient groups, the acute phase group exhibited significantly higher serum RGMa levels than did the remission group (p < 0.001). A multivariate analysis revealed a significant positive correlation between RGMa expression and EDSS score at admission, degree of MRI enhancement, and segmental length of spinal cord lesions. There was a significant negative correlation between the expression of RGMa in NMOSD and the time from attack to sampling or delta EDSS.

Conclusions

The current study suggests that RGMa may be considered a potential biomarker predicting the severity, disability, and clinical features of NMOSD.

A Novel Progress: Glial Cells and Inflammatory Pain

Inflammatory pain is the perception of noxious stimuli that occurs during inflammation or an immune response. Glial cells are widespread in the central and peripheral nervous systems, supporting and guiding the migration of neurons, participating in the immune response, forming the myelin sheath and blood-brain barrier, and maintaining the concentration of potassium ions outside nerve cells. Recent studies have shown that glial cells have a significant connection with the production and development of inflammatory pain. This article reviews the relationship, mechanisms, therapeutic targets between five types of glial cells and inflammatory pain, and the medicine composition that can effectively inhibit inflammatory pain. It expands the study on the mechanism of glial cells regulating pain and provides new ideas for the therapy of inflammatory pain.

Injectable polymeric nanoparticle hydrogel system for long-term anti-inflammatory effect to treat osteoarthritis

Treatment of osteoarthritis (OA) by administration of corticosteroids is a commonly used method in clinics using anti-inflammatory medicine. Oral administration or intra-articular injection of corticosteroids can reduce the pain and progress of cartilage degeneration, but they are usually insufficient to show local and long-term anti-inflammatory effects because of their fast clearance in the body. In this study, we suggest an injectable anti-OA drug depot system for sustained drug release that provides long-term effective therapeutic advantages. Amphiphilic poly(organophosphazene), which has temperature-dependent nanoparticle forming and sol-gel transition behaviors when dissolved in aqueous solution, was synthesized for triamcinolone acetonide (TCA) delivery. Because hydrophobic parts of the polymer can interact with hydrophobic parts of the TCA, the TCA was encapsulated into the self-assembled polymeric nanoparticles. The TCA-encapsulated polymeric nanoparticles (TePNs) were well dispersed in an aqueous solution below room temperature so that they can be easily injected as a sol state into an intra-articular region. However, the TePNs solution transforms immediately to a viscose 3D hydrogel like a synovial fluid in the intra-articular region via the conducted body temperature. An in vitro TCA release study showed sustained TCA release for six weeks. One-time injection of the TePN hydrogel system in an early stage of OA-induced rat model showed a great inhibition effect against further OA progression. The OA-induced knees completely recovered as a healthy cartilage without any abnormal symptoms.

Repulsive Guidance Molecule-a and Central Nervous System Diseases

Repulsive guidance molecule-a (RGMa) is a member of glycosylphosphatidylinositol- (GPI-) anchored protein family, which has axon guidance function and is widely involved in the development and pathological processes of the central nervous system (CNS). On the one hand, the binding of RGMa and its receptor Neogenin can regulate axonal guidance, differentiation of neural stem cells into neurons, and the survival of these cells; on the other hand, RGMa can inhibit functional recovery of CNS by inhibiting axonal growth. A number of studies have shown that RGMa may be involved in the pathogenesis of CNS diseases, such as multiple sclerosis, neuromyelitis optica spectrum diseases, cerebral infarction, spinal cord injury, Parkinson's disease, and epilepsy. Targeting RGMa can enhance the functional recovery of CNS, so it may become a promising target for the treatment of CNS diseases. This article will comprehensively review the research progression of RGMa in various CNS diseases up to date.

Pathological spontaneous activity as a prognostic marker in chronic inflammatory demyelinating polyneuropathy

BACKGROUND AND PURPOSE

Monitoring of the disease course of patients with chronic inflammatory demyelinating polyneuropathy (CIDP) remains challenging because nerve conduction studies do not adequately correlate with functional disability. The prognostic value of pathological spontaneous activity (PSA) in needle electromyography (EMG) in different CIDP subgroups in a longitudinal context has, to date, not been analysed. We aimed to determine whether PSA was a prognostic marker or a marker of disease activity in a cohort of patients with CIDP.

METHODS

A total of 127 patients with CIDP spectrum disorder were retrospectively analysed over 57 ± 47 months regarding the occurrence of PSA (fibrillations and positive sharp waves). The presence of PSA at diagnosis, newly occurring PSA, and continuously present PSA were longitudinally correlated with clinical disability using the Inflammatory Neuropathy Cause and Treatment Overall Disability Sum Score (INCAT-ODSS) and CIDP subtype.

RESULTS

Pathological spontaneous activity occurred in 49.6% of all CIDP patients at first diagnosis. More frequent evidence of PSA was significantly associated with a higher INCAT-ODSS at the last follow-up. Continuous and new occurrence of PSA were associated with higher degree of disability at the last follow-up. The majority of patients with sustained evidence of PSA were characterized by an atypical phenotype, higher degree of disability, and the need for escalation of treatment.

CONCLUSIONS

Pathological spontaneous activity was associated with a higher degree of disability and occurred more frequently in atypical CIDP variants according to the longitudinal data of a large cohort of patients with CIDP. Our results showed that EMG examination was an adequate marker for disease progression and should be evaluated during the disease course.

Immunomodulatory and anti-oxidative effect of the direct TRPV1 receptor agonist capsaicin on Schwann cells

Background

Only few studies describe the impact of nutritive factors on chronic inflammatory demyelinating polyneuropathy (CIDP), an inflammatory disease of the peripheral nervous system. The active component of chili pepper, capsaicin, is the direct agonist of the transient receptor potential channel vanilloid subfamily member 1. Its anti-inflammatory effect in the animal model experimental autoimmune neuritis (EAN) has been previously demonstrated.

Methods

In the present study, we describe the anti-inflammatory and anti-oxidative influence of capsaicin on Schwann cells (SCs) in an in vitro setting. Hereby, we analyze the effect of capsaicin on Schwann cells’ gene expression pattern, major histocompatibility complex class II (MHC-II) presentation, and H₂O₂-induced oxidative stress. Furthermore, the effect of capsaicin on myelination was examined in a SC-dorsal root ganglia (DRG) coculture by myelin basic protein staining. Finally, in order to investigate the isolated effect of capsaicin on SCs in EAN pathology, we transplant naïve and capsaicin pre-treated SCs intrathecally in EAN immunized rats and analyzed clinical presentation, electrophysiological parameters, and cytokine expression in the sciatic nerve.

Results

In SC monoculture, incubation with capsaicin significantly reduces interferon gamma-induced MHC-II production as well as toll-like receptor 4 and intercellular adhesion molecule 1 mRNA expression. Calcitonin gene-related peptide mRNA production is significantly upregulated after capsaicin treatment. Capsaicin reduces H₂O₂-induced oxidative stress in SC in a preventive, but not therapeutic setting. In a SC-DRG coculture, capsaicin does not affect myelination rate. After intrathecal transplantation of naïve and capsaicin pre-treated SCs in EAN-immunized rats, naïve, but not capsaicin pre-treated intrathecal SCs, ameliorated EAN pathology in rats.

Conclusions

In conclusion, we were able to demonstrate a direct immunomodulatory and anti-oxidative effect of capsaicin in a SC culture by reduced antigen presentation and expression of an anti-inflammatory profile. Furthermore, capsaicin increases the resistance of SCs against oxidative stress. A primary effect of capsaicin on myelination was not proven. These results are in concordance with previous data showing an anti-inflammatory effect of capsaicin, which might be highly relevant for CIDP patients.

Neural microphysiological systems for in vitro modeling of peripheral nervous system disorders

PNS disease pathology is diverse and underappreciated. Peripheral neuropathy may result in sensory, motor or autonomic nerve dysfunction and can be induced by metabolic dysfunction, inflammatory dysfunction, cytotoxic pharmaceuticals, rare hereditary disorders or may be idiopathic. Current preclinical PNS disease research relies heavily on the use of rodent models. In vivo methods are effective but too time-consuming and expensive for high-throughput experimentation. Conventional in vitro methods can be performed with high throughput but lack the biological complexity necessary to directly model in vivo nerve structure and function. In this review, we survey in vitro PNS model systems and propose that 3D-bioengineered microphysiological nerve tissue can improve in vitro–in vivo extrapolation and expand the capabilities of in vitro PNS disease modeling.