Impairment of heme synthesis in myelin as potential trigger of multiple sclerosis

Exploring the Therapeutic Potential: Bioactive Molecules and Dietary Interventions in Multiple Sclerosis Management

Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease of the central nervous system, the etiology of which is still unclear. Its hallmarks are inflammation and axonal damage. As a disease primarily impacting younger individuals, the social cost of MS is high. It has been proposed that environmental factors, smoking, and dietary habits acting on a genetic susceptibility play a role in MS. Recent studies indicate that diet can significantly influence the onset and progression of MS. This review delves into the impact of natural bioactive molecules on MS development and explores the dietary interventions that hold promise in managing the disease. Dietary patterns, including ketogenic and Mediterranean diets, are discussed. Theories about the potential mechanistic associations beneath the noted effects are also proposed. Several dietary components and patterns demonstrated the potential for a significant impact on MS. However, extensive prospective clinical trials are necessary to fully understand the role of natural bioactive molecules as disease modifiers in MS.

A genome-wide association study provides insights into the genetic etiology of 57 essential and non-essential trace elements in humans

Trace elements are important for human health but may exert toxic or adverse effects. Mechanisms of uptake, distribution, metabolism, and excretion are partly under genetic control but have not yet been extensively mapped. Here we report a comprehensive multi-element genome-wide association study of 57 essential and non-essential trace elements. We perform genome-wide association meta-analyses of 14 trace elements in up to 6564 Scandinavian whole blood samples, and genome-wide association studies of 43 trace elements in up to 2819 samples measured only in the Trøndelag Health Study (HUNT). We identify 11 novel genetic loci associated with blood concentrations of arsenic, cadmium, manganese, selenium, and zinc in genome-wide association meta-analyses. In HUNT, several genome-wide significant loci are also indicated for other trace elements. Using two-sample Mendelian randomization, we find several indications of weak to moderate effects on health outcomes, the most precise being a weak harmful effect of increased zinc on prostate cancer. However, independent validation is needed. Our current understanding of trace element-associated genetic variants may help establish consequences of trace elements on human health.

Neuron Protection by EDTA May Explain the Successful Outcomes of Toxic Metal Chelation Therapy in Neurodegenerative Diseases

Many mechanisms have been related to the etiopathogenesis of neurodegenerative diseases (NDs) such as multiple sclerosis, amyotrophic lateral sclerosis, Parkinson’s disease, and Alzheimer’s disease. In this context, the detrimental role of environmental agents has also been highlighted. Studies focused on the role of toxic metals in the pathogenesis of ND demonstrate the efficacy of treatment with the chelating agent calcium disodium ethylenediaminetetraacetic acid (EDTA) in eliminating toxic metal burden in all ND patients, improving their symptoms. Lead, cadmium, aluminum, nickel, and mercury were the most important toxic metals detected in these patients. Here, I provide an updated review on the damage to neurons promoted by toxic metals and on the impact of EDTA chelation therapy in ND patients, along with the clinical description of a representative case.

Effects of endocrine disrupting chemicals on myelin development and diseases

In the central and peripheral nervous systems, myelin is essential for efficient conduction of action potentials. During development, oligodendrocytes and Schwann cells differentiate and ensure axon myelination, and disruption of these processes can contribute to neurodevelopmental disorders. In adults, demyelination can lead to important disabilities, and recovery capacities by remyelination often decrease with disease progression. Among environmental chemical pollutants, endocrine disrupting chemicals (EDCs) are of major concern for human health and are notably suspected to participate in neurodevelopmental and neurodegenerative diseases. In this review, we have combined the current knowledge on EDCs impacts on myelin including several persistent organic pollutants, bisphenol A, triclosan, heavy metals, pesticides, and nicotine. Besides, we presented several other endocrine modulators, including pharmaceuticals and the phytoestrogen genistein, some of which are candidates for treating demyelinating conditions but could also be deleterious as contaminants. The direct impacts of EDCs on myelinating cells were considered as well as their indirect consequences on myelin, particularly on immune mechanisms associated with demyelinating conditions. More studies are needed to describe the effects of these compounds and to further understand the underlying mechanisms in relation to the potential for endocrine disruption.

Relationship of Iron Metabolism and Short-Term Cuprizone Treatment of C57BL/6 Mice

One of the models to investigate the distinct mechanisms contributing to neurodegeneration in multiple sclerosis is based on cuprizone (CZ) intoxication. CZ is toxic to mature oligodendrocytes and produces demyelination within the central nervous system but does not cause direct neuronal damage. The CZ model is suitable for better understanding the molecular mechanism of de- and remyelination processes of oligodendrocytes. CZ is a copper chelating agent and it also affects the iron metabolism in brain and liver tissues. To determine the early effect of CZ treatment on iron homeostasis regulation, cytosolic and mitochondrial iron storage, as well as some lipid metabolism genes, we investigated the expression of respective iron homeostasis and lipid metabolism genes of the corpus callosum (CC) and the liver after short-term CZ administration. In the present study C57BL/6 male mice aged four weeks were fed with standard rodent food premixed with 0.2 w/w% CZ for two or eight days. The major findings of our experiments are that short-term CZ treatment causes significant changes in iron metabolism regulation as well as in the expression of myelin and lipid synthesis-related genes, even before apparent demyelination occurs. Both in the CC and the liver the iron uptake, utilization and storage are modified, though not always the same way or to the same extent in the two organs. Understanding the role of iron in short-term and long-term CZ intoxication could provide a partial explanation of the discrepant signs of acute and chronic MS. These could contribute to understanding the development of multiple sclerosis and might provide a possible drug target.

Effects of aging on the myelination of the optic nerve in rats

AIM OF THE STUDY

Cognitive decline due to aging is most probably the result of changes in the white matter in the central nervous system (CNS) and/or demyelination.

MATERIAL AND METHODS

We used electron microscopic analysis of the morphological changes in aging rats' optic nerves as an easily accessible part of the CNS.

RESULTS

Several age changes were observed in aging rats (36 months) vs. young adult rats (6 months), namely degeneration of axons, decreased packing density and morphological alterations of myelination, including the ballooning of some myelin sheaths, separation of myelin lamellae and degenerative changes in the oligodendrocytes population.

CONCLUSION

Cognitive decline related to aging may occur in part due to the disturbed myelination of axons in CNS white matter.

Myelin proteomics: the past, the unexpected and the future

Myelin proteomics has been the subject of intense research over the last decade, and its profiling has achieved good results by both in-gel and mass spectrometry-based techniques. 1280 proteins have been identified, a number expected to increase. Some of the identified proteins are as yet not established as true components of myelin. There appears to be a limit in our ability to discover markers of myelin biogenesis, function and disease. Myelin can be easily isolated free of contaminants, thanks to its lipidic nature, which however necessitates pretreatment with detergents before mass spectrometry analysis. Here, the key issue of solubilization of myelin proteins for mass spectrometry measurements is addressed. An in-depth characterization of the myelin proteome would have a profound impact on our knowledge of its pathology and physiology. Future quantitative proteomic studies of the low-abundance myelin protein complement, likely representing key regulatory components, may in future provide molecular description of the dysmyelinating/demyelinating diseases.

New immunological approaches in treating and diagnosing CNS diseases

The immune system evolved to launch effective and specific responses against pathogens. A key feature of this defense mechanism is its ability to differentiate between self and nonself. However, in autoimmune diseases, the host's immune system fails to discriminate self versus foreign. The CNS is further protected by the blood-brain barrier. In spite of its 'immune privilege,' the brain is not protected from autoimmunity; perhaps paradoxically xenoantibodies can be used to treat neurological diseases. We describe patents covering treatment methods for CNS diseases with suspected or demonstrated autoimmune etiology. These include multiple sclerosis and, Alzheimer's and Parkinson's disease. The goal is to less invasively, yet efficiently, treat neurological diseases. Although autoimmune responses are often detrimental, recent studies have begun to harness, boost and induce immune responses as a mechanism of treatment. The patents discussed herein highlight new treatments for Alzheimer's and Parkinson's disease, multiple sclerosis, and seizure disorders.

Is a hypothetical melanoma-like neuromelanin the underlying factor essential for the aetiopathogenesis and clinical manifestations of multiple sclerosis?

Background

Multiple sclerosis (MS) has undergone a significant increase in incidence in the industrialised nations over the last 130 years. Changing environmental factors, possibly infections or a lack of or altered timing of them, determine the prevalence of the disease. Although a plethora of aetiological factors, clearly evident in a group of children with MS, appear relevant, there may nevertheless be a single factor essential for the aetiopathogenesis and clinical manifestation of MS.

Description and discussion

This hitherto unknown factor is postulated to be a ‘melanoma-like neuromelanin’ (MLN) dependent on the activation of a gene for syncytin-1. An involvement of MLN could explain the diverse findings in the epidemiology, immunology and pathology of MS, requiring a consideration of a complex infectious background, the human leucocyte antigens, as well as cosmic radiation causing geomagnetic disturbances, vitamin D deficiency, smoking, and lower levels of uric acid.

Summary

In principle, the MLN-based concept is a unifying one, capable of explaining a number of characteristics of the disease. To date, MLN has not been addressed in studies on MS and future work will need to be done on human patients, as there is little or no neuromelanin (the precursor of MLN) in the animals used as experimental models in the study of MS.