Antidiabetics, statins and the risk of amyotrophic lateral sclerosis.

BACKGROUND: Medications that are used for treatment of metabolic disorders have been suggested to be associated with the development of amyotrophic lateral sclerosis (ALS). METHODS: To examine the associations of antidiabetics and statins with the subsequent risk of ALS we conducted a population-based nested case-control study of 2475 Swedish residents diagnosed with ALS during July 2006 to December 2013 and 12 375 population controls (five for each ALS case). We extracted information on filled prescriptions of antidiabetics and statins for both cases and controls from the Swedish Prescribed Drug Register during the years before ALS diagnosis. Conditional logistic regression was used to calculate odds ratios (ORs) for the associations of these medications with ALS risk. RESULTS: Patients with ALS were less likely to have been prescribed with antidiabetics compared with controls [OR, 0.76; 95% confidence intervals (CI), 0.65-0.90]. Conversely, statins were not associated with ALS risk overall (OR, 1.08; 95% CI, 0.98-1.19), although a positive association was noted among women (OR, 1.28; 95% CI, 1.10-1.48). The latter association was mostly explained by ALS cases being more likely to have a first prescription of statins during the year before diagnosis compared with controls (OR, 2.54; 95% CI, 1.84-3.49). CONCLUSIONS: The inverse association of antidiabetics with ALS is consistent with the previously reported inverse association between type 2 diabetes and ALS risk. The increase in prescription of statins during the year before ALS diagnosis deserves attention because it might reflect an acceleration of the course of ALS due to statin use.

Detection of BMAA in the human central nervous system.

Amyotrophic lateral sclerosis (ALS) is an extremely devastating neurodegenerative disease with an obscure etiology. The amino acid ß-N-methylamino-l-alanine (BMAA) produced by globally widespread phytoplankton has been implicated in the etiology of human motor neuron diseases [corrected]. BMAA was recently proven to be present in Baltic Sea food webs, ranging from plankton to larger Baltic Sea organisms, some serving as important food items (fish) for humans. To test whether exposure to BMAA in a Baltic Sea setting is reflected in humans, blood and cerebrospinal fluid (CSF) from individuals suffering from ALS were analyzed, together with sex- and age-matched individuals not inflicted with ALS. Ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and multiple reaction monitoring (MRM), in conjunction with diagnostic transitions revealed BMAA in three (12%) of the totally 25 Swedish individuals tested, with no preference for those suffering from ALS. The three BMAA-positive samples were all retrieved from the CSF, while BMAA was not detected in the blood. The data show that BMAA, potentially originating from Baltic Sea phytoplankton, may reach the human central nervous system, but does not lend support to the notion that BMAA is resident specifically in ALS-patients. However, while dietary exposure to BMAA may be intermittent and, if so, difficult to detect, our data provide the first demonstration of BMAA in the central nervous system of human individuals ante mortem quantified with UHPLC-MS/MS, and therefore calls for extended research efforts.

Multiple founder effects in spinal and bulbar muscular atrophy (SBMA, Kennedy disease) around the world.

SBMA (spinal and bulbar muscular atrophy), also called Kennedy disease, is an X-chromosomal recessive adult-onset neurodegenerative disorder caused by death of the spinal and bulbar motor neurones and dorsal root ganglia. Patients may also show signs of partial androgen insensitivity. SBMA is caused by a CAG repeat expansion in the first exon of the androgen receptor (AR) gene on the X-chromosome. Our previous study suggested that all the Nordic patients with SBMA originated from an ancient Nordic founder mutation, but the new intragenic SNP marker ARd12 revealed that the Danish patients derive their disease chromosome from another ancestor. In search of relationships between patients from different countries, we haplotyped altogether 123 SBMA families from different parts of the world for two intragenic markers and 16 microsatellites spanning 25 cM around the AR gene. The fact that different SBMA founder haplotypes were found in patients from around the world implies that the CAG repeat expansion mutation has not been a unique event. No expansion-prone haplotype could be detected. Trinucleotide diseases often show correlation between the repeat length and the severity and earlier onset of the disease. The longer the repeat, the more severe the symptoms are and the onset of the disease is earlier. A negative correlation between the CAG repeat length and the age of onset was found in the 95 SBMA patients with defined ages at onset.

Founder effect in spinal and bulbar muscular atrophy (SBMA) in Scandinavia.

We haplotyped 13 Finnish, 10 Swedish, 12 Danish and 2 Norwegian SBMA (spinal and bulbar muscular atrophy, Kennedy disease) families with a total of 45 patients and 7 carriers for 17 microsatellite markers spanning a 25.2 cM region around the androgen receptor gene on chromosome Xq11-q12 in search of a genetic founder effect. In addition, the haplotypes of 50 Finnish, 20 Danish and 22 Swedish control males were examined. All the Scandinavian SBMA families shared the same 18 repeat allele for the intragenic GGC repeat, which was present in only 24% of the controls. Linkage disequilibrium was also seen for the closest microsatellite markers. In addition, extended haplotypes of the Finnish, Swedish and Danish SBMA families revealed country-specific common founder haplotypes, which over time became gradually shortened by recombinations. No common haplotype was found among the controls. The data suggest that the SBMA mutation was introduced into western Finland 20 generations ago. Haplotype analysis implies a common ancestor for the majority of Scandinavian SBMA patients.

Phenotypic heterogeneity in motor neuron disease patients with CuZn-superoxide dismutase mutations in Scandinavia.

Four-hundred and fifty-one blood samples from Scandinavian patients with motor neuron disease were analysed for mutations in the CuZn-superoxide dismutase gene. Forty-one (9.6%) of the 427 patients with the amyotrophic lateral sclerosis (ALS) form of the disease were found to have a disease-associated mutation, and 14 of these patients were apparently sporadic cases. A mutation was found in 12 of the 51 families with recognized familial ALS. The five different mutations found (Ala4Val, Val14Gly, Asp76Tyr, Asp90Ala, Gly127insTGGG) have different genetic characteristics and are associated with very variable phenotypes spanning from rapidly progressing disease with only lower motor neuron signs to very slowly progressing disease with both the upper and lower motor neuron systems affected. The patients showed different sites of onset, though the progressive bulbar palsy form of the disease appears to be rare among patients with a CuZn-superoxide dismutase mutation. The progression of motor signs and symptoms followed the same basic pattern in patients with different mutations. Extra-motor system symptoms were frequent among patients with a CuZn-superoxide dismutase mutation. The results suggest that patients with mutations in the CuZn-superoxide dismutase gene constitute one disease entity. The Val14Gly and Asp76Tyr mutations have not been reported before, and the latter is the first mutation to be found in exon 3 of the CuZn-superoxide dismutase gene.

[Improved knowledge resulted in better care of ALS]. / Kunskapslyft har medfört bättre vård vid ALS.

An example of the substantial advances in the management and treatment of patients with amyotrophic lateral sclerosis (ALS) in recent years is the introduction in 1996 of Riluzole, the first drug with verified effect on the disease course. The article consists in a review of recent advances in our knowledge of the pathogenic mechanisms, diagnosis, management and treatment of ALS.

Pitfalls in the evaluation of isometric strength (TQNE) data in ALS.

The phase of rapid reduction of isometric strength in single muscle groups was identified and its slope was calculated in patients studied with the TQNE method. This parameter was studied in the extremities and in respiration in 4 ALS patients and 4 PMA (progressive spinal muscle atrophy) patients. The slopes of the strength reduction in these muscle groups and their mean values exceeded the slopes of the corresponding megascores; this difference was larger in the extremities than in respiration. It is concluded that repeated spirometry gives a good expression of reduction of muscle strength ir ALS, and is well suited for monitoring treatment effects.

Further studies on the occurrence of serum autoantibodies against a membrane bound AChE fraction in ALS/MND patients and controls.

Autoantibodies of the IgG and IgA types against a membrane bound AChE fraction were studied in the serum of ALS/MND patients, controls with neurological or autoimmune diseases, and normal controls. About 70% of ALS and progressive spinal muscle atrophy (PMA) patients had antibodies of both Ig types (titre > 1/81), compared to about 12% of neurologically diseased controls and about 8% of the other controls. A higher proportion of individuals having autoantibodies was found in the older age group in both patients and controls.

Selective vulnerability of alpha motor neurons in ALS: relation to autoantibodies toward acetylcholinesterase (AChE) in ALS patients.

The degenerative process in amyotrophic lateral sclerosis (ALS) concerns primarily alpha motor neurons in the spinal cord and brain stem, and neurons forming descending pathways to the cord, especially in the pyramidal tract. Some degeneration of large peripheral sensory nerve fibers often occurs too, but preganglionic autonomic neurons and gamma motor neurons are most often spared in the disease. The vulnerability of alpha motor neurons compared to other types of neurons in ALS is discussed in relation to retrograde axoplasmic transport from peripheral blood of foreign noxious macromolecules, interneuronal transport of such molecules, and neuronal surface structure properties relevant to uptake for retrograde axoplasmic transport. Certain differences in these aspects between alpha motor neurons and other neuronal types exist. Some differences concern the neuronal turnover of acetylcholinesterase (AChE), which could be of special interest in view of the recent demonstration of regular occurrence of autoantibodies towards this enzyme in ALS patients.

Immunoglobulin-mediated activity against red blood cells in the saliva of amyotrophic lateral sclerosis (ALS) patients.

Immunoglobulin (Ig)-mediated activity in plasma directed towards normal blood type matched red blood cells (RBC) inducing haemolysis in vitro has earlier been demonstrated to be a characteristic feature in ALS-patients. In this study, saliva of ALS-patients, normal and diseased controls was tested with the same in vitro test. An increased degree of haemolysis was induced by the ALS-patient as compared with control samples. The activity thus found in saliva had the same basic characteristics as that earlier described for plasma; it reacted similarly to serial dilution and was retained in salivary Ig. The effect on red blood cells of saliva from patients with bulbar paralysis was larger than that of saliva from ALS-patients lacking bulbar symptoms. It is discussed whether cytotoxic Ig in saliva could be pathophysiologically active in bulbar paralysis by means of passage through the oral mucosa and local action on motor end plates in perioral muscles.

Myelin breakdown in the posterior funiculus of the kitten after dorsal rhizotomy. A qualitative and quantitative light and electron microscopic study.

Morphological aspects of myelin breakdown in the posterior funiculus during Wallerian degeneration were studied in kittens subjected to lumbosacral dorsal rhizotomies 6-8 days after birth. The first sign of myelin breakdown was characterized by swollen or shrunken nerve fibers. Shortly thereafter there was an increased occurrence of collapsed myelin sheaths and later of rounded myelin bodies. Myelin was clearly seen in microglial cells. Correlative observations on Marchi-stained material indicted the simultaneous and frequent appearance of Marchi-positive bodies (MPB:s) and myelin bodies. Due to the rapidity of the degeneration process in the kitten, the increase in the occurrence of Marchi-positive granules (MPG:s) seemed to start concomitantly with increased occurrence of MPB:s. However, the frequent occurrence of MPG:s outlasted that for MPB:s. The findings indicate that the MPB:s may be the counterpart to myelin bodies and the MPG:s to lipid droplets. Microglial cells may be responsible for the primary uptake of degenerating myelin and the subsequent transformation of myelin bodies to lipid droplets. The much faster breakdown of myelin and elimination of lipid material in the degenerating posterior funiculus of the kitten, as compared to the adult, seemed to be due not only to the lower myelin content in the kitten, but also to a higher density of microglial and a greater efficiency in the myelin breakdown process in the degenerating posterior funiculus of the kitten.

Immunoglobulins from patients with amyotrophic lateral sclerosis affect human erythrocyte acetylcholinesterase.

Human erythrocyte acetylcholinesterase (AChE) solubilized with Triton X-100 and obtained as a complex with micelles containing Triton and membrane phospholipids was incubated with immunoglobulins (Igs) from patients with amyotrophic lateral sclerosis (ALS) and from normal individuals. The temperature dependence of the AChE activity was determined. Biphasic (broken) Arrhenius plots were obtained with control Igs with the break point at 32.8 +/- 0.3 degrees C (SD, n = 18) indicating that the enzyme changes its conformation at this temperature. With ALS-Igs monophasic (linear) plots were observed in 14 cases and a biphasic in one case. ALS-Igs prevent the conformational change occurring at the break point temperature. The activation energy at physiological temperature increased by 60% from 2.4 to 3.8 kcal/mol (10.0-15.9 kJ/mol) which implies that ALS-Igs inhibit AChE. Thus, ALS-patients have autoantibodies that change the normal behaviour of erythrocyte AChE and which bind to the enzyme molecule or/and to phospholipids associated with the enzyme. At least part of the autoantibodies should be directed against the enzyme molecule, since a change in the Arrhenius plot was also observed in a control experiment with AChE which probably had micelles without any phospholipids. This enzyme was isolated by affinity chromatography and was washed with a buffer containing Triton X-100 before desorption from the affinity column, a treatment known to remove all phospholipids from erythrocyte AChE.

Nature and properties of cytotoxic plasma activity in amyotrophic lateral sclerosis.

Cytotoxic activity of plasma towards normal red blood cells in patients with amyotrophic lateral sclerosis (ALS) has been studied as a function of progressive plasma dilution and compared with plasma from patients with Charcot-Marie-Tooth's disease (CMT). At progressive dilution the hemolysis by ALS-plasma showed a specific pattern that differed qualitatively and quantitatively from that of normal plasma as well as CMT and persisted up to a dilution of 1:6561. Differences in dilution pattern were found when comparing different clinical types of ALS. There was evidence for a partial complement dependency of the reaction that brings about the hemolysis provoked by ALS plasma. Experiments with plasma fractionated by gel filtration and with isolated immunoglobulins produced evidence for cytotoxic properties of IgA and IgG from ALS plasma. The observations speak in favor of a consistency between the observations of plasma cytotoxicity in ALS and earlier observations on immunological abnormalities in the disease.

Cytotoxic activity in the plasma of amyotrophic lateral sclerosis (ALS) patients against normal erythrocytes. Quantitative determinations.

Erythrocytes from healthy controls were incubated during 5.5 h under physiological conditions in own plasma, and plasma from blood type-matched ALS patients and diseased controls. Free haemoglobin (Hb) was repeatedly measured spectrophotometrically as a measure of haemolysis. Using a standardized procedure, the interexperimental variation in Hb release during incubation in own control plasma was kept very low in a large series of incubations (n = 77). This indicated that the condition of the erythrocytes had been constant. Parallel incubations in plasma from ALS patients (n = 20) rendered a clear-cut increase in Hb release, which in all cases exceeded the confidence interval of the controls. There was no correlation between Hb release in the ALS group and age, sex, type of disease or duration of symptoms. The cytotoxic effect of ALS plasma was abolished by heating to 56 degrees C. In a material of incubations in plasma of diseased controls (traumatic spinal cord disease, Guillain-Barré syndrome), the haemolysis was slightly larger than in control plasma, but in all cases smaller than in ALS plasma.

Myelin breakdown and elimination in the posterior funiculus of the adult cat after dorsal rhizotomy: a light and electron microscopic qualitative and quantitative study.

Adult cats were subjected to unilateral dorsal L6, L7, and S1 rhizotomy. After survival times of 1-1,552 days the degeneration of axons and myelin sheaths and the elimination of degenerating myelin was studied qualitatively and quantitatively with light and electron microscopy and in Marchi-stained sections in the posterior funiculus in T12-L2. Degeneration was first observed as swollen or shrunken nerve fibers. Somewhat later there was an increased occurrence of collapsed myelin sheaths. The latter lost their myelin periods and appeared to be transformed into myelin bodies. The occurrence of myelin bodies coincided temporally with the presence of many Marchi-positive bodies. Later, an increasing number of intracellularly located lipid droplets occurred, paralleled by the occurrence of a great number of Marchi-positive granules and crystalline structures. Profiles of collapsed myelin sheaths, myelin bodies, and lipid droplets were frequently seen in the cytoplasm of microglial cells. Later, astrocytes and perivascular cells became filled with numerous lipid droplets. The findings suggest that microglial cells take up collapsed myelin sheaths and within these cells the sheaths become transformed into myelin bodies and subsequently into lipid droplets. These two products of myelin disintegration appear to correspond to the Marchi-positive structures seen during the degeneration process. The lipid droplets appear to be transported to astrocytes and perivascular cells.

Increased fragility of erythrocytes from amyotrophic lateral sclerosis (ALS) patients provoked by mechanical stress.

Erythrocytes from patients with amyotrophic lateral sclerosis (ALS) and controls were suspended in an electrolyte-substrate medium and subjected to mechanical stress by centrifugation under standardized conditions. Subsequent spectrophotometric analysis of the medium disclosed a significantly higher degree of haemolysis in samples from ALS-patients than from controls. The observation gives further evidence for the existence of an abnormality of the red cells in the disease. The nature and possible significance of this abnormality in relation to the pathogenesis of ALS is as yet unknown, but notably there was no significant correlation between the degree of cell abnormality as manifested by haemolysis and the duration of the disease in the individual patient.