Multiple sclerosis - the remarkable story of a baffling disease

Role of fenofibrate in multiple sclerosis

Multiple sclerosis (MS) is the most frequent inflammatory and demyelinating disease of the central nervous system (CNS). The underlying pathophysiology of MS is the destruction of myelin sheath by immune cells. The formation of myelin plaques, inflammation, and injury of neuronal myelin sheath characterizes its neuropathology. MS plaques are multiple focal regions of demyelination disseminated in the brain's white matter, spinal cords, deep grey matter, and cerebral cortex. Fenofibrate is a peroxisome proliferative activated receptor alpha (PPAR-α) that attenuates the inflammatory reactions in MS. Fenofibrate inhibits differentiation of Th17 by inhibiting the expression of pro-inflammatory signaling. According to these findings, this review intended to illuminate the mechanistic immunoinflammatory role of fenofibrate in mitigating MS neuropathology. In conclusion, fenofibrate can attenuate MS neuropathology by modulating different pathways, including oxidative stress, autophagy, mitochondrial dysfunction, inflammatory-signaling pathways, and neuroinflammation.

Roles of Adenosine Receptor (subtypes A1 and A2A) in Cuprizone-Induced Hippocampal Demyelination

Hippocampal demyelination in multiple sclerosis (MS) has been linked with cognitive deficits, however, patients could benefit from treatment that induces oligodendroglial cell function and promotes remyelination. We investigated the role of A1 and A2A adenosine receptors (AR) in regulating oligodendrocyte precursor cells (OPCs) and myelinating oligodendrocyte (OL) in the demyelinated hippocampus using the cuprizone model of MS. Spatial learning and memory were assessed in wild type C57BL/6 mice (WT) or C57BL/6 mice with global deletion of A1 (A1AR-/-) or A2A AR (A2AAR-/-) fed standard or cuprizone diet (CD) for four weeks. Histology, immunofluorescence, Western blot and TUNEL assays were performed to evaluate the extent of demyelination and apoptosis in the hippocampus. Deletion of A1 and A2A AR alters spatial learning and memory. In A1AR-/- mice, cuprizone feeding led to severe hippocampal demyelination, A2AAR-/- mice had a significant increase in myelin whereas WT mice had intermediate demyelination. The A1AR-/- CD-fed mice displayed significant astrocytosis and decreased expression of NeuN and MBP, whereas these proteins were increased in the A2AAR-/- CD mice. Furthermore, Olig2 was upregulated in A1AR-/- CD-fed mice compared to WT mice fed the standard diet. TUNEL staining of brain sections revealed a fivefold increase in the hippocampus of A1AR-/- CD-fed mice. Also, WT mice fed CD showed a significant decrease expression of A1 AR. A1 and A2A AR are involved in OPC/OL functions with opposing roles in myelin regulation in the hippocampus. Thus, the neuropathological findings seen in MS may be connected to the depletion of A1 AR.

Immune Regulatory Functions of Macrophages and Microglia in Central Nervous System Diseases

Macrophages can be characterized as a very multifunctional cell type with a spectrum of phenotypes and functions being observed spatially and temporally in various disease states. Ample studies have now demonstrated a possible causal link between macrophage activation and the development of autoimmune disorders. How these cells may be contributing to the adaptive immune response and potentially perpetuating the progression of neurodegenerative diseases and neural injuries is not fully understood. Within this review, we hope to illustrate the role that macrophages and microglia play as initiators of adaptive immune response in various CNS diseases by offering evidence of: (1) the types of immune responses and the processes of antigen presentation in each disease, (2) receptors involved in macrophage/microglial phagocytosis of disease-related cell debris or molecules, and, finally, (3) the implications of macrophages/microglia on the pathogenesis of the diseases.

Women in the field of multiple sclerosis: How they contributed to paradigm shifts

History is full of women who made enormous contributions to science. While there is little to no imbalance at the early career stage, a decreasing proportion of women is found as seniority increases. In the multiple sclerosis (MS) field, 44% of first authors and only 35% of senior authors were female. So, in this review, we highlight ground-breaking research done by women in the field of MS, focusing mostly on their work as principal investigators. MS is an autoimmune disorder of the central nervous system (CNS), with evident paradigm shifts in the understating of its pathophysiology. It is known that the immune system becomes overactivated and attacks myelin sheath surrounding axons. The resulting demyelination disrupts the communication signals to and from the CNS, which causes unpredictable symptoms, depending on the neurons that are affected. Classically, MS was reported to cause mostly physical and motor disabilities. However, it is now recognized that cognitive impairment affects more than 50% of the MS patients. Another shifting paradigm was the involvement of gray matter in MS pathology, formerly considered to be a white matter disease. Additionally, the identification of different T cell immune subsets and the mechanisms underlying the involvement of B cells and peripheral macrophages provided a better understanding of the immunopathophysiological processes present in MS. Relevantly, the gut-brain axis, recognized as a bi-directional communication system between the CNS and the gut, was found to be crucial in MS. Indeed, gut microbiota influences not only different susceptibilities to MS pathology, but it can also be modulated in order to positively act in MS course. Also, after the identification of the first microRNA in 1993, the role of microRNAs has been investigated in MS, either as potential biomarkers or therapeutic agents. Finally, concerning MS therapeutical approaches, remyelination-based studies have arisen on the spotlight aiming to repair myelin loss/neuronal connectivity. Altogether, here we emphasize the new insights of remarkable women that have voiced the impact of cognitive impairment, white and gray matter pathology, immune response, and that of the CNS-peripheral interplay on MS diagnosis, progression, and/or therapy efficacy, leading to huge breakthroughs in the MS field.

Bile acids and neurological disease

This review will focus on how bile acids are being used in clinical trials to treat neurological diseases due to their central involvement with the gut-liver-brain axis and their physiological and pathophysiological roles in both normal brain function and multiple neurological diseases. The synthesis of primary and secondary bile acids species and how the regulation of the bile acid pool may differ between the gut and brain is discussed. The expression of several bile acid receptors in brain and their currently known functions along with the tools available to manipulate them pharmacologically are examined, together with discussion of the interaction of bile acids with the gut microbiome and their lesser-known effects upon brain glucose and lipid metabolism. How dysregulation of the gut microbiome, aging and sex differences may lead to disruption of bile acid signalling and possible causal roles in a number of neurological disorders are also considered. Finally, we discuss how pharmacological treatments targeting bile acid receptors are currently being tested in an array of clinical trials for several different neurodegenerative diseases.

Epidemiology and Pathophysiology of Multiple Sclerosis

PURPOSE OF REVIEW

This article provides an overview of genetic, environmental, and lifestyle risk factors affecting the disease course of multiple sclerosis (MS) and reviews the pathophysiologic characteristics of both relapsing and progressive MS.

RECENT FINDINGS

The prevalence of MS has increased in recent decades, and costs of care for patients with MS have risen dramatically. Black, Asian, and Hispanic individuals may be at risk for more severe MS-related disability. Multiple genetic MS risk factors have been identified. Factors such as low vitamin D levels and a history of Epstein-Barr virus, smoking, and obesity, especially during childhood, also influence MS risk. Traditionally thought to be a T-cell-mediated disease, recent research has highlighted the additional roles of B cells and microglia in both relapsing and progressive MS.

SUMMARY

Complex interactions between genetic, environmental, and lifestyle factors affect the risk for MS as well as the disease course. People of color have historically been underrepresented in both MS clinical trials and literature, but current research is attempting to better clarify unique considerations in these groups. MS pathology consists of the focal inflammatory lesions that have been well characterized in relapsing MS, as well as a more widespread neurodegenerative component that is posited to drive progressive disease. Recent advances in characterization of both the inflammatory and neurodegenerative aspects of MS pathophysiology have yielded potential targets for future therapeutic options.

Alzheimer's disease drug development pipeline: 2022

Introduction

Alzheimer's disease (AD) represents a global health crisis. Treatments are needed to prevent, delay the onset, slow the progression, improve cognition, and reduce behavioral disturbances of AD. We review the current clinical trials and drugs in development for the treatment of AD.

Methods

We searched the governmental website clinicaltrials.gov where are all clinical trials conducted in the United States must be registered. We used artificial intelligence (AI) and machine learning (ML) approaches to ensure comprehensive detection and characterization of trials and drugs in development. We use the Common Alzheimer's Disease Research Ontology (CADRO) to classify drug targets and mechanisms of action of drugs in the pipeline.

Results

As of January 25, 2022 (index date for this study) there were 143 agents in 172 clinical trials for AD. The pipeline included 31 agents in 47 trials in Phase 3, 82 agents in 94 trials in Phase 2, and 30 agents in 31 trials in Phase 1. Disease-modifying therapies represent 83.2% of the total number of agents in trials; symptomatic cognitive enhancing treatments represent 9.8% of agents in trials; and drugs for the treatment of neuropsychiatric symptoms comprise 6.9%. There is a diverse array of drug targets represented by agents in trials including nearly all CADRO categories. Thirty-seven percent of the candidate agents in the pipeline are repurposed drugs approved for other indications. A total of 50,575 participants are needed to fulfill recruitment requirements for all currently active clinical trials.

Discussion

The AD drug development pipeline has agents representing a substantial array of treatment mechanisms and targets. Advances in drug design, outcome measures, use of biomarkers, and trial conduct promise to accelerate the delivery of new and better treatments for patients with AD.

Highlights

There are 143 drugs in the current Alzheimer's disease (AD) drug development pipeline.Disease-modifying therapies represent 83.2% of the candidate treatments.Current trials require 50,575 participants who will donate 3,878,843 participant-weeks to clinical trials.The biopharmaceutical industry sponsors 50% of all clinical trials including 68% of Phase 3 trials.Sixty-three percent of Phase 3 trials and 46% of Phase 2 trials include non-North American clinical trial site locations indicating the global ecosystem required for AD drug development.

[Inflammatory diseases of the central nervous system]

Autoimmune inflammatory diseases of the central nervous system (CNS) can be a diagnostic challenge despite advanced imaging techniques. Diagnostic errors can have fatal consequences (e. g. tumefactive lesions) as inappropriate treatment can exacerbate the symptoms of the patients. The aim of this article is to provide help in decision making for selected autoimmune inflammatory diseases of the CNS, in order not to fall into diagnostic traps. The primary focus is on lesions in the neurocranium as inflammatory diseases of the spinal cord were already extensively discussed in a previous article.

Translational Block in Stroke: A Constructive and "Out-of-the-Box" Reappraisal

Why can we still not translate preclinical research to clinical treatments for acute strokes? Despite > 1000 successful preclinical studies, drugs, and concepts for acute stroke, only two have reached clinical translation. This is the translational block. Yet, we continue to routinely model strokes using almost the same concepts we have used for over 30 years. Methodological improvements and criteria from the last decade have shed some light but have not solved the problem. In this conceptual analysis, we review the current status and reappraise it by thinking "out-of-the-box" and over the edges. As such, we query why other scientific fields have also faced the same translational failures, to find common denominators. In parallel, we query how migraine, multiple sclerosis, and hypothermia in hypoxic encephalopathy have achieved significant translation successes. Should we view ischemic stroke as a "chronic, relapsing, vascular" disease, then secondary prevention strategies are also a successful translation. Finally, based on the lessons learned, we propose how stroke should be modeled, and how preclinical and clinical scientists, editors, grant reviewers, and industry should reconsider their routine way of conducting research. Translational success for stroke treatments may eventually require a bold change with solutions that are outside of the box.

Nutraceuticals and diet in human health and disease. The special issue at a glance

This first Special Issue collects fifteen original research and up-to-date review articles addressing the beneficial properties of herbal products, nutrient supplements, dietary regimens, and functional food for the complementary therapy of human pathologies. In these articles, renowned scholars present and discuss the curative effects and the molecular mechanisms of action of nutraceuticals, medicinal herbs, and dietary regimens that have been proven effective in the treatment of cancers, metabolic syndrome, fatty liver disease, hearth arrythmia and neurodegenerative disorders.