Gangliosides and neurological diseases

Pathogenic role of ganglioside metabolism in neurodegenerative diseases

Ganglioside metabolism is altered in several neurodegenerative diseases, and this may participate in several events related to the pathogenesis of these diseases. Most changes occur in specific areas of the brain and their distinct membrane microdomains or lipid rafts. Antiganglioside antibodies may be involved in dysfunction of the blood-brain barrier and disease progression in these diseases. In lipid rafts, interactions of glycosphingolipids, including ganglioside, with proteins may be responsible for the misfolding events that cause the fibril and/or aggregate processing of disease-specific proteins, such as α-synuclein, in Parkinson's disease, huntingtin protein in Huntington's disease, and copper-zinc superoxide dismutase in amyotrophic lateral sclerosis. Targeting ganglioside metabolism may represent an underexploited opportunity to design novel therapeutic strategies for neurodegeneration in these diseases.

Is there a decrease in Guillain-Barré syndrome incidence after bovine ganglioside withdrawal in Italy? A population-based study in the Local Health District of Ferrara, Italy

There have been many reports of cases of Guillain-Barré syndrome (GBS) after therapeutic injection of bovine ganglioside preparations with the result that they were withdrawn in Italy in December 1993. As the relationship between bovine gangliosides and GBS has not yet been established, a further epidemiological investigation in the Local Health District (LHD) of Ferrara, Italy, was carried out in the years 1994-2001 to verify whether the incidence of GBS had changed after ganglioside withdrawal. The other aim of this investigation was to update the incidence of GBS in this area since the two previous investigations we carried out showed an increase in incidence from the years 1981-1987 to the years 1988-1993. The cases of GBS were identified prospectively. To guarantee completeness of case ascertainment, an intensive retrospective survey of all possible sources of cases for the entire study period was performed. The mean annual crude incidence rate in the years 1994-2001 (based on 26 new cases) was 1.97 per 100,000 population (95% CI 1.29-2.89), whereas it had been 1.87 per 100,000 population (95% CI 1.35-2.52) in the years 1981-1993 (based on 43 cases) when gangliosides were available. The age-adjusted rates were almost identical (1.66 and 1.65 per 100,000 population, respectively). Although ganglioside administration could have triggered, on the basis of an individual susceptibility, an immunologic reaction which produced GBS, the incidence of GBS in the study area did not change after ganglioside withdrawal. In the whole period 1981-2001, a temporal pattern of incidence was reported with an increase towards a peak in 1990-1992 and a progressive decline thereafter. This temporal pattern did not seem related to ganglioside withdrawal, and no definite explanation for it was found which could imply that the disease incidence is less stable than it was deemed.

Role of gangliosides in tumour progression: a molecular target for cancer therapy?

In a number of patients with tumours of either neuroectodermal or epithelial origin, polysialylated gangliosides (e.g. GD3) are over-expressed. The mechanism of ganglioside over-expression may be different for the two classes of tumour and could represent distinct secondary genetic mutations or epigenetic changes affecting the enzymes (transferases and/or hydrolases) controlling the metabolic interconversions of these gangliosides. Tumour cells of neuroectodermal origin (e.g. melanomas and brain tumours) are known to produce and shed polysialylated gangliosides, whereas paracrine signal(s) from tumour cells of epithelial origin (e.g. carcinomas of cervix, lung, prostate, breast, head and neck, colon and ovary) may stimulate over-expression and shedding from tumour infiltrating mesenchymal cells (e.g. macrophages and/or fibroblasts). This cellular membrane over-expression and shedding of acidic glycosphingolipids into the interstitial spaces and blood of cancer patients may play a central role in increased tumour cell growth, lack of immune cell recognition and neovascularization and could represent a molecular target for cancer therapy.

Gangliosides and Guillain-Barré syndrome

Cases of Guillain-Barré syndrome (GBS) associated with parenteral use of gangliosides have been reported in several European countries. To evaluate the hypothesis of association between ganglioside exposure and occurrence of GBS, a case-control study was conducted. GBS cases discharged during 1989 from public and private hospitals in three Italian provinces were identified: 42 GBS cases and 420 controls matched on age and gender were enrolled. Data of onset of symptoms of GBS was taken from clinical records. Exposure status of subjects was ascertained through the regional computerized drug prescription monitoring system. The odds ratio of association between ganglioside use, in the 30 days prior to onset of symptoms, and GBS was 9.1 (95% confidence interval 2.8-29.4). Although there are formidable difficulties in distinguishing prodromal therapy of GBS from drug causation, the association with ganglioside therapy is strong and supportive of the hypothesis of a role of ganglioside preparations in the occurrence of GBS.

Gangliosides. Their role in clinical neurology

Gangliosides are normal constituent of mammalian vertebrate cell membranes and are particularly abundant in the central and peripheral nervous systems. The biological effects of exogenously administered gangliosides have been extensively investigated in vitro and in experimental animal models where they have neuronotrophic and neuritogenic properties. Despite these findings there is still little evidence that treatment with parenteral gangliosides in humans can be effective in peripheral neuropathies or other neuromuscular diseases. The initial preliminary reports on the positive effects of GM1 in cerebrovascular diseases and spinal cord injury need to be confirmed in larger controlled trials. At the same time the occasional development of an acute motor neuropathy clinically presenting as the Guillain-Barré syndrome and associated with high titres of anti-ganglioside antibodies highlights the risks of their widespread use before more consistent data on their efficacy become available.

The Therapeutic Role of Gangliosides in Neurological Disorders

Numerous in vitro and in vivo experimental animal studies have demonstrated that gangliosides, particularly GMI ganglioside (siagoside), may stimulate or accelerate the repair of peripheral and central nervous system neurons after various types of damage. Clinical studies of GMl in peripheral neuropathies and stroke, disorders in which the effects of GM 1 have been studied most extensively, have yielded inconsistent results. Problems of inadequate study design, inclusion of heterogenous clinical popUlations and variations in dosage, duration of treatment and timing of initial administration make it difficult to compare results from individual studies and to conclusively assess efficacy of GMl treatment. Therefore, further clinical studies of gangliosides seem warranted.Despite efforts to link gangliosides with the development of Guillain-Barre syndrome, there are no valid data to support such an association. Gangliosides, in particular GM I, are well tolerated after repeated administration to humans and do not appear to be immunogenic.GM1 may be a useful therapeutic agent if administered to particular patients with a specific spectrum of symptoms and disease severity. In addition, to be effective the agents need to be administered in appropriate dosages and at an appropriate time after neuronal injury. Human clinical trials of gangliosides should continue cautiously and with restraint.

[Brain gangliosides and memory formation]

It is generally accepted that the process of molecular facilitation (= Bahnung) of neuronal circuits by means of stabilization of synaptic contacts represents the structural basis for memory formation. On the basis of physiological, electron microscopic, biochemical, and physicochemical data, a concept is presented speaking in favor of the idea that interactions between brain gangliosides (= amphiphilic sialic acid-containing glycosphingolipids with peculiar physicochemical properties), calcium, and functional membraneous proteins (ion channels, ion pumps, receptors, kinases) play a crucial modulatory role in the transmission and storage of information.