Sleep disturbances in elderly subjects: an epidemiological survey in an Italian district.

OBJECTIVES: Disturbed sleep is common in elderly people and has been related to comorbidities. The aim of this study was to evaluate the prevalence of sleep problems and their relationship with chronic disease in an elderly population. MATERIALS AND METHODS: The whole population of subjects aged more than 65 years, in the municipality of Vecchiano, Pisa was considered as eligible and underwent a clinical interview and a questionnaire about insomnia, sleepiness, snoring and sleep apnea. A model of logistic regression was applied to the data. RESULTS: The participation rate was 60.3% (1427 subjects). Insomnia was observed in 44.2% of our population, while sleepiness in 31.3%, snoring in 47.2% and sleep apnea in 9.0%. The most common diseases associated with sleep symptoms were depression, cognitive decline and diabetes. CONCLUSIONS: Our results confirm that sleep problems are very common in elderly subjects and closely related to medical and psychiatric illnesses.

Diagnostic approach to mitochondrial disorders: the need for a reliable biomarker.

Mitochondrial diseases (MD) are disorders caused by impairment of the mitochondrial electron transport chain (ETC). Phenotypes are polymorphous and may range from pure myopathy to multisystemic disorders. The genetic defect can be located on mitochondrial or nuclear DNA. The ETC is needed for oxidative phosphorylation (which provides the cell with the most efficient energetic outcome in terms of ATP production), and consists of five multimeric protein complexes located in the inner mitochondrial membrane. The ETC also requires cytochrome c and a small electron carrier, coenzyme Q10. One of the pathogenic mechanisms of ETC disorders is excessive accumulation of reactive oxygen species (ROS). Mitochondrial dysfunction and oxidative stress appear to have a strong impact also on the pathogenesis of neurodegenerative diseases. At present, diagnosis of MD requires a complex approach: measurement of serum lactate, exercise testing, electromyography, magnetic resonance spectroscopy, muscle histology and enzymology, and genetic analysis. Biomarkers are molecules associated with biological processes or regulatory mechanisms. A reliable biomarker for the screening or diagnosis of MD is still needed. In this paper we review the diagnostic approach to MD, from serum lactate to other blood and urinary markers, from muscular biopsy to imaging studies, and we highlight some potentially interesting perspectives in this field.

Mitochondria, cognitive impairment, and Alzheimer's disease.

To date, the beta amyloid (Abeta) cascade hypothesis remains the main pathogenetic model of Alzheimer's disease (AD), but its role in the majority of sporadic AD cases is unclear. The "mitochondrial cascade hypothesis" could explain many of the biochemical, genetic, and pathological features of sporadic AD. Somatic mutations in mitochondrial DNA (mtDNA) could cause energy failure, increased oxidative stress, and accumulation of Abeta, which in a vicious cycle reinforce the mtDNA damage and the oxidative stress. Despite the evidence of mitochondrial dysfunction in AD, no causative mutations in the mtDNA have been detected so far. Indeed, results of studies on the role of mtDNA haplogroups in AD are controversial. In this review we discuss the role of the mitochondria, and especially of the mtDNA, in the cascade of events leading to neurodegeneration, dementia, and AD.

Lack of association between mtDNA haplogroups and Alzheimer's disease in Tuscany.

Mitochondrial DNA (mtDNA) haplogroup-specific polymorphisms were previously related to several neurodegenerative diseases, including Alzheimer's disease (AD). However, the precise role of mtDNA haplogroups in the neurodegenerative cascade leading to AD is still unclear. In this work we have genotyped predefined European mtDNA haplogroups in 209 patients with AD and 191 matched controls. In order to minimise the risk of "genetic contamination", which could lead to false associations between gene markers and disease, we were careful to enrol in the study only patients and controls of clear Tuscan origin (with at least three generations of Tuscanborn relatives). The frequency of the haplogroups did not differ between the two groups, and no correlation with gender, ApoE genotype, age of onset or disease status was observed. Further studies will be required to define the contribution of mtDNA haplogroups, if any, to the pathogenesis of AD. A correct population selection, in order to minimise the risk of genetic contamination, is essential in these studies.

Epilepsy and limb girdle muscular dystrophy type 2A: double trouble, serendipitous finding or new phenotype?

Autosomal recessive limb girdle muscular dystrophies (LGMD) type 2A are a group of disorders characterised by progressive involvement of proximal limb girdle muscles and caused by changes in the CAPN3 gene. Involvement of tissues other than the skeletal muscle has not been reported so far. Here we describe the unusual association of LGMD2A and idiopathic generalised epilepsy in a 14-year-old girl.