Transfer of a cyanobacterial neurotoxin within a temperate aquatic ecosystem suggests pathways for human exposure.

beta-methylamino-L-alanine (BMAA), a neurotoxic nonprotein amino acid produced by most cyanobacteria, has been proposed to be the causative agent of devastating neurodegenerative diseases on the island of Guam in the Pacific Ocean. Because cyanobacteria are widespread globally, we hypothesized that BMAA might occur and bioaccumulate in other ecosystems. Here we demonstrate, based on a recently developed extraction and HPLC-MS/MS method and long-term monitoring of BMAA in cyanobacterial populations of a temperate aquatic ecosystem (Baltic Sea, 2007-2008), that BMAA is biosynthesized by cyanobacterial genera dominating the massive surface blooms of this water body. BMAA also was found at higher concentrations in organisms of higher trophic levels that directly or indirectly feed on cyanobacteria, such as zooplankton and various vertebrates (fish) and invertebrates (mussels, oysters). Pelagic and benthic fish species used for human consumption were included. The highest BMAA levels were detected in the muscle and brain of bottom-dwelling fishes. The discovery of regular biosynthesis of the neurotoxin BMAA in a large temperate aquatic ecosystem combined with its possible transfer and bioaccumulation within major food webs, some ending in human consumption, is alarming and requires attention.

The Swedish motor neuron disease quality registry.

OBJECTIVE: We set up the Swedish Motor Neuron Disease (MND) Quality Registry to assure early diagnosis and high-quality health care for all MND patients (mainly amyotrophic lateral sclerosis, ALS), and to create a research base by prospectively following the entire MND population in Sweden. METHODS: Since 2015, the MND Quality Registry continuously collects information about a wide range of clinical measures, biological samples, and quality of life outcomes from all MND patients recruited at the time of MND diagnosis in Sweden and followed at each clinic visit approximately every 12 weeks. The Registry includes an Internet based patient own reporting portal that involves patients in the registration of their current symptoms and health status. RESULTS: As of 20th January 2017, the MND Quality Registry included 99% of the MND patients of the Stockholm area (N = 194), consisting mostly of ALS patients (N = 153, 78.9%), followed by patients labeled as MND due to a neurophysiology finding but not fulfilling the criteria for ALS (N = 20, 10.3%), primary lateral sclerosis (N = 13, 6.7%), and progressive spinal muscular atrophy patients (N = 8, 4.1%). A higher proportion of these patients were women (N = 100, 52%), and women and men had a similar age at symptoms onset (59 years). CONCLUSIONS: Main strengths of the MND Quality Registry are its clinical, quantitative, qualitative, and prospective nature, providing the researchers potential means of identifying appropriate candidates for clinical trials and other research projects, as well as assuring to the patients an effective and adequate time spent on-site with the healthcare professionals.

Amyotrophic lateral sclerosis and cancer: a register-based study in Sweden.

Comorbidity of cancer with ALS has been studied previously. Detailed description of the temporal relationship between cancer and ALS is, however, lacking. We conducted a nested case-control study of ALS in Sweden during 1987-2009, including 5481 cases of ALS identified from the Swedish Patient Register and 27,405 controls randomly selected from the general Swedish population. Odds ratios (ORs) for association of ALS with previous cancer diagnosis and incidence rate ratios (IRRs) of cancer after diagnosis were calculated to compare ALS patients with ALS-free individuals. Overall, a previous cancer diagnosis was not associated with subsequent risk of ALS (OR 1.00; 95% CI 0.91-1.10). No overall association was observed for any specific cancer type. An increased risk of ALS was observed during the first year after cancer diagnosis (OR 1.50; 95% CI 1.17-1.92). In contrast, a lower risk of cancer was observed in ALS patients after diagnosis compared with ALS-free individuals (IRR 0.84; 95% CI 0.69-1.02). The risk reduction was seen primarily two or more years after ALS diagnosis (IRR 0.64; 95% CI 0.45-0.88). Our results provide no evidence for comorbidity of cancer and ALS overall. Surveillance biases seem the most likely explanation for the limited associations detected.

Infection of the central nervous system, sepsis and amyotrophic lateral sclerosis.

BACKGROUND: Severe infections may lead to chronic inflammation in the central nervous system (CNS) which may in turn play a role in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). The relentless progression and invasive supportive treatments of ALS may on the other hand induce severe infections among ALS patients. METHODOLOGY AND PRINCIPAL FINDINGS: The present study included 4,004 ALS patients identified from the Swedish Patient Register during 1991-2007 and 20,020 age and sex matched general population controls. Conditional logistic regression was used to estimate the odds ratios (ORs) of ALS given a previous hospitalization for CNS infection or sepsis. Cox models were used to estimate the hazard ratios (HRs) of hospitalization for CNS infection or sepsis after ALS diagnosis. Overall, previous CNS infection (OR: 1.3, 95% confidence interval [CI]: 0.8, 2.4) or sepsis (OR: 1.2, 95% CI: 0.9, 1.6) was not associated with ALS risk. However, compared to ALS free individuals, ALS cases were more likely to be hospitalized for sepsis after diagnosis (HR: 2.6, 95% CI: 1.9, 3.5). We did not observe a higher risk of CNS infection after ALS diagnosis. CONCLUSIONS/SIGNIFICANCE: Our results suggest that acute and severe infections unlikely contribute to the development of ALS; however, ALS patients are at a higher risk of sepsis after diagnosis, compared to ALS free individuals.

Amyotrophic lateral sclerosis in Sweden, 1991-2005.

OBJECTIVES: To investigate the temporal trend of amyotrophic lateral sclerosis (ALS) incidence in Sweden between January 1, 1991, and December 31, 2005, and to explore incidence variations according to major demographic factors. DESIGN: Population-based study. SETTING: Academic research. PARTICIPANTS: All incident cases of ALS identified through the Swedish Inpatient Register between January 1, 1991, and December 31, 2005. MAIN OUTCOME MEASURE: Age-standardized incidence rates were calculated by applying the observed age-specific incidence rates to the age distribution of the Swedish population in 1991. A linear regression model was used to assess the potential trend of the incidence during calendar years. We also followed up the entire population registered in the 1990 Population and Housing Census for incidence of ALS. Relative risk and 95% confidence interval of ALS associated with demographic variables were estimated using Poisson regression models. RESULTS: The age-standardized incidence rates increased from 2.32 per 100,000 person-years in 1991-1993 to 2.98 per 100,000 person-years in 2003-2005, representing an annual increase of approximately 2% during the 15 years (P value for trend, .002). The age-specific incidence rates increased in all age groups except those younger than 50 years. The observed increase remained significant when restricting the analysis to individuals born in Sweden (P value for trend, <.001). Compared with individuals born from April through June, those born from October through December were at 11% increased risk of ALS (95% confidence interval, 1.01-1.23). CONCLUSIONS: The incidence of ALS has been increasing during the last 15 years in Sweden. Further studies are warranted to explore the underlying reasons for this observed trend.