Alcoholic polyneuropathy. Clinical forms and pathogenetically based approaches to therapy

The number of cases of alcoholism in Russia is gradually decreasing, but still significantly affects the overall health indicators of the population. One of its frequent complications is alcoholic polyneuropathy. The article deals with the pathogenetic mechanisms of the occurrence and development of the disease, its forms, classification, and clinical picture. The damage to the nervous system in patients with alcoholism depends on the frequency of alcohol consumption, the dose, the type of drinks that were consumed, malnutrition, genetic predisposition and individual characteristics that determine the level of alcohol dehydrogenase and aldehyde dehydrogenase. In the clinical picture, a toxic form of alcoholic polyneuropathy is currently distinguished, associated with the direct effect of toxic alcohol metabolites on somatic and autonomic nerve fibers, thiamine deficiency, resulting from a deficiency of B vitamins, and mixed forms. According to the rate of development of clinical manifestations, there are acute forms of alcoholic polyneuropathy (thiamine deficiency) and chronic forms (toxic). The article discusses the possibilities of diagnostics using modern instrumental and laboratory methods of research, primarily electroneuromyography. With the help of this method of investigation, in alcoholic polyneuropathy, signs of axonal damage are most often detected, and in the thiamine-deficient form, it is possible to determine signs of secondary demyelination. The authors emphasize the importance of differential diagnosis with other pathologies. The article highlights the current understanding of the main therapeutic strategies, treatment options for patients with alcoholic polyneuropathy. Therapy of patients suffering from alcoholic polyneuropathy includes refusal of alcohol abuse, normalization of nutrition, medication. For drug therapy, B vitamins and antioxidants are used. The drug with a recognized antioxidant effect is alpha-lipoic acid. A clinical case was analyzed on the basis of our own clinical observation of a mixed form of alcoholic polyneuropathy.

White Matter Pathology as a Barrier to Gangliosidosis Gene Therapy

The gangliosidoses are a family of neurodegenerative lysosomal storage diseases that have recently seen promising advances in gene therapy. White matter deficits are well established components of gangliosidosis pathology that are now receiving more attention because they are partially refractory to correction by gene therapy. After a brief synopsis of normal myelinogenesis, this review outlines current viewpoints on the origin of white matter deficits in the gangliosidoses and potential obstacles to treating them effectively by gene therapy. Dysmyelinogenesis (failure of myelin sheaths to form properly) is proposed as the predominant contributor to white matter pathology, but precise mechanistic details are not well understood. The involvement of neuronal storage deficits may extend beyond secondary demyelination (destruction of myelin due to axonal loss) and contribute to dysmyelinogenesis. Preclinical studies in animal models of the gangliosidoses have substantially improved lifespan and quality of life, leading to the initiation of several clinical trials. However, improvement of white matter pathology has lagged behind other metrics and few evidence-based explanations have been proposed to date. Research groups in the field are encouraged to include myelin-specific investigations in future gene therapy work to address this gap in knowledge.

Central vein sign for differential diagnosis of demyelinating diseases of CNS

The search for highly sensitive and highly specific biomarkers of MS, including neuroimaging biomarkers, continues. One of such biomarkers is the central vein sign detectable on SW and T2-weighted MR images. The sensitivity and specificity of methods used for central vein sign detection vary. This article describes two clinical cases of patients with similar neurological symptoms which required making differential diagnosis between multiple sclerosis and secondary demyelination in the presence of a systemic disorder (systemic lupus erythematosus). In addition to routine MR sequences, we used SWI generated by a 3T scanner. The lesions with the central vein sign were counted; the proportion of perivenular lesions was determined. In the multiple sclerosis case, all the lesions were perivenular; the proportion of lesions with the central vein sign in the patient with secondary demyelination in the presence of systemic lupus erythematosus was 16.7%. The use of SW images improved the informative value of the analysis.

Brain stem and spinal cord demyelination due to acute carbon monoxide poisoning

Demyelination throughout the brain stem and spinal cord caused by acute carbon monoxide (CO) poisoning has not been previously reported. Magnetic resonance imaging (MRI) has revealed that acute CO poisoning primarily affects the subcortical white matter of the bilateral cerebral hemispheres and basal ganglia. Here we report the case of a patient with delayed neuropsychological sequelae (DNS) due to acute CO poisoning. A 28-year-old man was admitted to our department following a suicide attempt by acute CO poisoning. After a six-month pseudo-recovery period, he was diagnosed with DNS, with MRI evidence of demyelinating change of the bilateral cerebral peduncles. Demyelination was identified throughout the brain stem, expanding from the bilateral cerebral peduncles to the medulla oblongata, occurring approximately six months after poisoning. One and a half years after acute CO poisoning, demyelination of the cervical and thoracic spine was observed, most notable in the lateral and posterior cords. It is evident that previously published research on this topic is extremely limited. Perhaps in severe cases of acute CO poisoning the fatality rate is higher, leading to fewer surviving cases for possible study. This may be because a more severe case of acute CO poisoning would result in the higher likelihood of secondary demyelination. This research indicates that clinicians should be aware of the risk of secondary demyelination and take increased precautions such as vitamin B supplementation and administration of low-dose corticosteroids for an extended period of time in order to reduce the extent and severity of demyelination.

Chronic inflammatory demyelinating polyradiculoneuropathy induced by paclitaxel

Background: Peripheral neuropathies in cancer are most often due to neurotoxic chemotherapeutic agents. Approximately 30% of patients receiving neurotoxic chemotherapy (CTX) will suffer from chemotherapy-induced peripheral neuropathy (CIPN). Paclitaxel is an extremely effective chemotherapeutic agent for the treatment of breast, ovarian, and lung cancer. However, paclitaxel-induced peripheral neuropathy occurs in 59-87% of patients who receive this drug. Paclitaxel is an anti-tubulin drug that causes microtubule stabilization, resulting in distal axonal degeneration, secondary demyelination and nerve fiber loss. Case: We present a case of a 68-year-old female patient with history of breast cancer who presented sensorial ataxia and progressive muscle weakness two months after starting CTX with paclitaxel. The physical examination showed tetraparesis with proximal predominance, areflexia, severe hypopalesthesia and postural instability. Electroneuromyography showed the existence of asymmetric demyelinating polyradiculoneuropathy, with conduction block and temporal dispersion in practically all evaluated nerves. The cerebrospinal fluid confirmed the albumin-cytological dissociation. Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) was confirmed and patient underwent monthly treatment with methylprednisolone with good response. Discussion: Evidences has implicated neuroinflammation in the development of PIPN. While most CTX drugs do not cross the blood-brain-barrier, they readily penetrate the blood-nerve-barrier and bind to and accumulate in dorsal root ganglia and peripheral axons. CTX can induce neuroinflammation through activation of immune and immune- like glial cells. In fact, immune cells (e.g., macrophages, lymphocytes) and glial cells (e.g., Schwann cells) in the peripheral nervous system play important role in the induction and maintenance of neuropathy. Conclusion: CIDP should be included in the spectrum of CIPN.

Inhibition of neutral sphingomyelinase 2 promotes remyelination

Myelination requires a highly organized synthesis of multiple lipid species that regulate myelin curvature and compaction. For reasons that are not understood, central nervous system remyelinated axons often have thin myelin sheaths with a disorganized structure susceptible to secondary demyelination. We found that expression of the sphingomyelin hydrolase neutral sphingomyelinase 2 (nSMase2) during the differentiation of oligodendrocyte progenitor cells (OPCs) to myelinating oligodendrocytes changes their response to inflammatory cytokines. OPCs do not express nSMase2 and exhibit a protective/regenerative response to tumor necrosis factor–α and interleukin-1β. Oligodendrocytes express nSMase2 and exhibit a stress response to cytokine challenge that includes an overproduction of ceramide, a sphingolipid that forms negative curvatures in membranes. Pharmacological inhibition or genetic deletion of nSMase2 in myelinating oligodendrocytes normalized the ceramide content of remyelinated fibers and increased thickness and compaction. These results suggest that inhibition of nSMase2 could improve the quality of myelin and stabilize structure.

Inhibition of neutral sphingomyelinase-2 facilitates remyelination

For reasons that are not completely understood, remyelination is often incomplete, producing thin myelin sheaths with disorganized structure. We investigated the cellular basis for this altered myelin structure, and found that the response of oligodendrocyte progenitor cells (OPCs), and mature oligodendrocytes to TNFα and IL-1β is modified by the expression of the sphingomyelin hydrolase nSMase2. OPCs do not express nSMase2, and exhibit a protective response to these cytokines manifest by decreased ceramide, increased sphingosine 1-phosphate, and increased cell motility. Mature oligodendrocytes express nSMase2, and respond to TNFα and IL-1β with a stress phenotype, evidenced by increased ceramide, decreased sphingosine, and active caspase 3. Pharmacological inhibition or a targeted genetic deletion of nSMase2in vivoincreased myelin thickness, and enhanced myelin compaction. These results suggest that inhibition of nSMase2 improves the quality of new myelin by protecting maturing/myelinating oligodendrocytes. Pharmacological inhibition of nSMase2 following a demyelinating event could stabilize the structure of these newly formed myelin sheaths and protect them from secondary demyelination.

Combination Treatment of C16 Peptide and Angiopoietin-1 Alleviates Neuromyelitis Optica in an Experimental Model

Neuromyelitis optica (NMO) is an autoimmune inflammatory demyelinating disease that mainly affects the spinal cord and optic nerve, causing blindness and paralysis in some individuals. Moreover, NMO may cause secondary complement-dependent cytotoxicity (CDC), leading to oligodendrocyte and neuronal damage. In this study, a rodent NMO model, showing typical NMO pathogenesis, was induced with NMO-IgG from patient serum and human complement. We then tested whether the combination of C16, an αvβ3 integrin-binding peptide, and angiopoietin-1 (Ang1), a member of the endothelial growth factor family, could alleviate NMO in the model. Our results demonstrated that this combination therapy significantly decreased disease severity, inflammatory cell infiltration, secondary demyelination, and axonal loss, thus reducing neural death. In conclusion, our study suggests a possible treatment that can relieve progressive blindness and paralysis in an animal model of NMO through improvement of the inflammatory milieu.

Visual evoked potentials in diagnostics of optic neuropathy associated with renal failure

Chronic renal failure is associated with many neurological complications. Due to accumulation of uremic neurotoxins axonal degeneration with its secondary demyelination occurs, which results in development of polineuropathy in 60-100% of patients with chronic renal failure. One of the most severe peripheral neuropathy is optic neuropathy. It is associated with visual deterioration and reduction in quality of life. Symptoms of the optic neuropathy may appear either before or after dialysis therapy. They often worsen after renal transplant, probably due to immunosuppressive regimen. Early diagnostics of the optic neuropathy became possible by using visual evoked potentials (VEP). This reliable, sensitive and noninvasive technique provides a direct measure of subclinical impairment of visual pathways. Among hemodialysed or immunosupressed patients one can observe abnormal VEP parameters – especially prolonged latency of the P100 component, less often fluctuation of its amplitude. These alterations are pronounced even if clinical examination reveals no abnormalities. This review presents a summary of current use of visual evoked potentials in monitoring of patients with chronic renal failure.

Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica (NMO) is an inflammatory demyelinating central nervous system disease. It has been classically defined as a monophasic, isolated co-occurrence of optic neuritis and transverse myelitis with uncertain relationship to multiple sclerosis. In the past decade, however, NMO has emerged as a distinct disorder associated with serum antibodies that target the astrocyte water channel aquaporin-4, distinguishing it from multiple sclerosis. The specificity of aquaporin-4 antibodies has led to appreciation of a wider spectrum of clinical and neuroimaging features, termed NMO spectrum disorders (NMOSD), than was encompassed by the classic NMO definition. Moreover, immunopathological studies have demonstrated that aquaporin-4 antibodies have pathogenic potential and that the disorder is a primary astrocytopathy with secondary demyelination. This chapter discusses the clinical definition and diagnosis of NMOSD and approaches to management, many informed by rapid advances in the understanding of NMO pathobiology.