Laquinimod has no effects on brain volume or cellular CNS composition in the F1 3xTg-AD/C3H mouse model of Alzheimer's disease

Diclofenac reduces the risk of Alzheimer's disease: a pilot analysis of NSAIDs in two US veteran populations

Background:

Our aim was to determine whether specific nonsteroidal anti-inflammatory (NSAID) agents are associated with a decreased frequency of Alzheimer’s disease (AD).

Materials and methods:

Days of drug exposure were determined for diclofenac, etodolac, and naproxen using US Department of Veterans Affairs (VA) pharmacy transaction records, combined from two separate VA sites. AD diagnosis was established by the International Classification of Diseases, ninth revision (ICD-9)/ICD-10 diagnostic codes and the use of AD medications. Cox regression survival analysis was used to evaluate the association between AD frequency and NSAID exposure over time. Age at the end of the study and the medication-based disease burden index (a comorbidity index) were used as covariates.

Results:

Frequency of AD was significantly lower in the diclofenac group (4/1431, 0.28%) compared with etodolac (328/14,646, 2.24%), and naproxen (202/12,203, 1.66%). For regression analyses, naproxen was chosen as the comparator drug, since it has been shown to have no effect on the development of AD. Compared with naproxen, etodolac had no effect on the development of AD, hazard ratio (HR) 1.00 [95% confidence interval (CI): 0.84–1.20, p = 0.95]. In contrast, diclofenac had a significantly lower HR of AD compared with naproxen, HR 0.25 (95% CI: 0.09–0.68, p <0.01). After site effects were controlled for, age at end of the study (HR = 1.08, 95% CI: 1.07–1.09, p <0.001) was also found to influence the development of AD, and the medication-based disease burden index was a strong predictor for AD, HR 5.17 (95% CI: 4.60–5.81) indicating that as comorbidities increase, the risk for AD increases very significantly.

Conclusion:

Diclofenac, which has been shown to have active transport into the central nervous system, and which has been shown to lower amyloid beta and interleukin 1 beta, is associated with a significantly lower frequency of AD compared with etodolac and naproxen. These results are compelling, and parallel animal studies of the closely related fenamate NSAID drug class.

Progression of Alzheimer's disease and effect of scFv-h3D6 immunotherapy in the 3xTg-AD mouse model: An in vivo longitudinal study using Magnetic Resonance Imaging and Spectroscopy

Alzheimer's disease (AD) is an incurable disease that affects most of the 47 million people estimated as living with dementia worldwide. The main histopathological hallmarks of AD are extracellular β-amyloid (Aβ) plaques and intracellular neurofibrillary tangles (NFTs) composed of hyperphosphorylated tau protein. In recent years, Aβ-immunotherapy has been revealed as a potential tool in AD treatment. One strategy consists of using single-chain variable fragments (scFvs), which avoids the fragment crystallizable (Fc) effects that are supposed to trigger a microglial response, leading to microhemorrhages and vasogenic edemas, as evidenced in clinical trials with bapineuzumab. The scFv-h3D6 generated by our research group derives from this monoclonal antibody, which targets the N-terminal of the Aβ peptide and recognizes monomers, oligomers and fibrils. In this study, 3xTg-AD mice were intraperitoneally and monthly treated with 100 μg of scFv-h3D6 (a dose of ~3.3 mg/kg) or PBS, from 5 to 12 months of age (-mo), the age at which the mice were sacrificed and samples collected for histological and biochemical analyses. During treatments, four monitoring sessions using magnetic resonance imaging and spectroscopy (MRI/MRS) were performed at 5, 7, 9, and 12 months of age. MRI/MRS techniques are widely used in both human and mouse research, allowing to draw an in vivo picture of concrete aspects of the pathology in a non-invasive manner and allowing to monitor its development across time. Compared with the genetic background, 3xTg-AD mice presented a smaller volume in almost all cerebral regions and ages examined, an increase in both the intra and extracellular Aβ_1-42 at 12-mo, and an inflammation process at this age, in both the hippocampus (IL-6 and mIns) and cortex (IL-6). In addition, treatment with scFv-h3D6 partially recovered the values in brain volume, and Aβ, IL-6, and mIns concentrations, among others, encouraging further studies with this antibody fragment.

Laquinimod Supports Remyelination in Non-Supportive Environments

Inflammatory demyelination, which is a characteristic of multiple sclerosis lesions, leads to acute functional deficits and, in the long term, to progressive axonal degeneration. While remyelination is believed to protect axons, the endogenous-regenerative processes are often incomplete or even completely fail in many multiple sclerosis patients. Although it is currently unknown why remyelination fails, recurrent demyelination of previously demyelinated white matter areas is one contributing factor. In this study, we investigated whether laquinimod, which has demonstrated protective effects in active multiple sclerosis patients, protects against recurrent demyelination. To address this, male mice were intoxicated with cuprizone for up to eight weeks and treated with either a vehicle solution or laquinimod at the beginning of week 5, where remyelination was ongoing. The brains were harvested and analyzed by immunohistochemistry. At the time-point of laquinimod treatment initiation, oligodendrocyte progenitor cells proliferated and maturated despite ongoing demyelination activity. In the following weeks, myelination recovered in the laquinimod- but not vehicle-treated mice, despite continued cuprizone intoxication. Myelin recovery was paralleled by less severe microgliosis and acute axonal injury. In this study, we were able to demonstrate that laquinimod, which has previously been shown to protect against cuprizone-induced oligodendrocyte degeneration, exerts protective effects during oligodendrocyte progenitor differentiation as well. By this mechanism, laquinimod allows remyelination in non-supportive environments. These results should encourage further clinical studies in progressive multiple sclerosis patients.

Activation of the miR-34a-Mediated SIRT1/mTOR Signaling Pathway by Urolithin A Attenuates D-Galactose-Induced Brain Aging in Mice

Despite tremendous advances in modern medicine, effective prevention or therapeutic strategies for age-related neurodegenerative diseases such as Alzheimer's disease (AD) remain limited. Currently, accumulating evidence has demonstrated that microRNAs (miRNAs) are increasingly associated with age-related diseases and are emerging as promising therapeutic targets. Urolithin A, a metabolite compound resulting from the transformation of ellagitannins by gut bacteria, has been reported to have anti-oxidant, anti-inflammatory, and anti-apoptotic properties. The present study primarily focused on the ameliorative effect of urolithin A on aging mice and on the exploration of the potential mechanisms of such an ameliorative effect on cognitive impairment and brain aging. In this study, we first tested the neuroprotective effect of urolithin A using an in vitro H2O2-induced PC12 cell oxidative damage model. The in vivoD-gal-induced brain aging model showed that urolithin A significantly suppressed the upregulation of miR-34a induced by D-gal. Moreover, target genes associated with miR-34a were also examined. Urolithin A supplementation ameliorated apoptosis induced by D-gal and rescued miR-34a overexpression-induced impaired autophagy in brain aging mice after a 2-month administration. Furthermore, urolithin A activated autophagy by upregulating the SIRT1 signaling pathway and downregulating the mTOR signaling pathway. In conclusion, urolithin A may exert neuroprotective effects and may aid in preventing D-gal-induced brain aging through activation of the miR-34a-mediated SIRT1/mTOR signaling pathway.

Defining standard enzymatic dissociation methods for individual brains and spinal cords in EAE

Objective

To determine the capacity, effectiveness, efficiency, and reliability of select tissue dissociation methods to isolate mononuclear cells from the CNS of mice with experimental autoimmune encephalomyelitis (EAE).

Methods

As part of an assay qualification, we tested the isolation method Percoll PLUS vs a commercially available enzymatic Neural Tissue Dissociation Kit (Kit), and the enzymes accutase and papain in C57BL/6 mice with active EAE. In a stepwise approach, we applied the following 4 criteria to each dissociation method: (1) mononuclear cell viability post-processing was required to be ≥80% per brain or spinal cord sample, (2) absolute live mononuclear cell numbers was required to be ≥5 × 10⁵ per brain or spinal cord sample of mice with clinical EAE, (3) test-retest reliability had to be verified, and (4) the absolute mononuclear cell numbers in brain and spinal cord had to correlate with the EAE disease course.

Results

Enzymatic dissociations allowed for greatly increased cell yield and specifically allowed for downstream assays from individual brains and spinal cords in C57BL/6 mice with EAE. All enzymatic dissociations provided a more efficient and effective method for isolating mononuclear cells from brains and spinal cord. Only the Kit assay provided a significant correlation between absolute mononuclear cell numbers in the spinal cord and EAE disease severity.

Conclusions

Enzymatic dissociation of CNS tissue of C57BL/6 mice with active EAE with the Kit should be the standard method. The identification of optimized CNS dissociation methods in EAE has the potential to identify cellular events that are pertinent to MS pathogenesis.