Diego Robles Mazzotti

Prevalence and correlates for sleep complaints in older adults in low and middle income countries: a 10/66 Dementia Research Group study.

BACKGROUND Although it is well recognized that the prevalence of sleep complaints increases with age, estimates in developing countries are still unknown. The present study aims to estimate the prevalence and prevalence ratios of the correlates of sleep complaints in a large population of older adults from low and middle income countries (LAMICs). METHODS A cross-sectional survey was performed in 16,680 65 year-old or older residents in catchment areas of Cuba, the Dominican Republic, Peru, Venezuela, Mexico, China, India, and Puerto Rico (10/66 Dementia Research Group study). Information about socio-demographic factors, lifestyle, health, and sleep complaints was obtained. Results were standardized by age, sex, household clustering, and residence site (urban or rural). Prevalence ratios were derived for each country and fixed effects meta-analyses were used to combine them. RESULTS The standardized prevalence of sleep complaints varied from 9.1% (China) to 37.7% (India). The meta-analysis showed that female gender, urban residence, low educational level, low physical activity status, high pain scores, poor health, higher memory impairment score, presence of major depression, mild cognitive impairment, and high number of co-morbidities were associated with sleep complaints. CONCLUSIONS This study robustly characterized the prevalence of sleep complaints in large samples of the elderly in LAMICs and identified potential risk factors that may be specific to these populations. This approach can help to direct health-care efforts related to sleep disturbances in these countries.

Adenosine Deaminase Polymorphism Affects Sleep EEG Spectral Power in a Large Epidemiological Sample

Slow wave oscillations in the electroencephalogram (EEG) during sleep may reflect both sleep need and intensity, which are implied in homeostatic regulation. Adenosine is strongly implicated in sleep homeostasis, and a single nucleotide polymorphism in the adenosine deaminase gene (ADA G22A) has been associated with deeper and more efficient sleep. The present study verified the association between the ADA G22A polymorphism and changes in sleep EEG spectral power (from C3-A2, C4-A1, O1-A2, and O2-A1 derivations) in the Epidemiologic Sleep Study (EPISONO) sample from São Paulo, Brazil. Eight-hundred individuals were subjected to full-night polysomnography and ADA G22A genotyping. Spectral analysis of the EEG was carried out in all individuals using fast Fourier transformation of the signals from each EEG electrode. The genotype groups were compared in the whole sample and in a subsample of 120 individuals matched according to ADA genotype for age, gender, body mass index, caffeine intake status, presence of sleep disturbance, and sleep-disturbing medication. When compared with homozygous GG genotype carriers, A allele carriers showed higher delta spectral power in Stage 1 and Stages 3+4 of sleep, and increased theta spectral power in Stages 1, 2 and REM sleep. These changes were seen both in the whole sample and in the matched subset. The higher EEG spectral power indicates that the sleep of individuals carrying the A allele may be more intense. Therefore, this polymorphism may be an important source of variation in sleep homeostasis in humans, through modulation of specific components of the sleep EEG.

Association Between Uric Acid Levels and Obstructive Sleep Apnea Syndrome in a Large Epidemiological Sample

Introduction Recurrent hypoxia, which is associated with obstructive sleep apnea syndrome (OSAS), leads to an increase in the degradation of adenosine triphosphatase into xanthine, which in turn increases uric acid concentrations. Objective The current study aimed to determine whether an association exists between OSAS and uric acid levels in the peripheral blood from a representative population of Sao Paulo (Brazil). Methods A population-based survey adopting a probabilistic 3-stage cluster sample of Sao Paulo was used to represent the population according to gender, age, and socioeconomic class. A total of 1,042 volunteers underwent polysomnography recordings for OSAS diagnosis, blood pressure assessment, and biochemical blood analysis, and answered questionnaires. Results Uric acid levels were correlated with most important risk factors for OSAS, such as AHI, desaturation time and index, minimum oxyhemoglobin saturation (SpO2), blood pressure, cholesterol, BMI, triglycerides and arousal, and with OSAS itself. Also, uric acid was increased in OSAS volunteers even after controlling for all confounders. Hyperuricemic volunteers presented lower mean and minimum SpO2 and increased desaturation index. Importantly, minimum SpO2 was a significant predictor of uric acid levels, which in turn was considered an independent predictor for OSAS in the binary logistic model. However, a ROC curve analysis for establishing cut-off points for uric acid levels as a biomarker of OSAS revealed moderate sensitivity and specificity. Conclusion A strong association was found between uric acid levels and OSAS in a representative sample of the population of Sao Paulo. Although they do not qualify for a biomarker alone, uric acid levels may be involved in OSAS severity and should be considered in sleep apnea management in the future.

Whole blood genome-wide gene expression profile in males after prolonged wakefulness and sleep recovery

Although the specific functions of sleep have not been completely elucidated, the literature has suggested that sleep is essential for proper homeostasis. Sleep loss is associated with changes in behavioral, neurochemical, cellular, and metabolic function as well as impaired immune response. Using high-resolution microarrays we evaluated the gene expression profiles of healthy male volunteers who underwent 60 h of prolonged wakefulness (PW) followed by 12 h of sleep recovery (SR). Peripheral whole blood was collected at 8 am in the morning before the initiation of PW (Baseline), after the second night of PW, and one night after SR. We identified over 500 genes that were differentially expressed. Notably, these genes were related to DNA damage and repair and stress response, as well as diverse immune system responses, such as natural killer pathways including killer cell lectin-like receptors family, as well as granzymes and T-cell receptors, which play important roles in host defense. These results support the idea that sleep loss can lead to alterations in molecular processes that result in perturbation of cellular immunity, induction of inflammatory responses, and homeostatic imbalance. Moreover, expression of multiple genes was downregulated following PW and upregulated after SR compared with PW, suggesting an attempt of the body to re-establish internal homeostasis. In silico validation of alterations in the expression of CETN3, DNAJC, and CEACAM genes confirmed previous findings related to the molecular effects of sleep deprivation. Thus, the present findings confirm that the effects of sleep loss are not restricted to the brain and can occur intensely in peripheral tissues.

The role inflammatory response genes in obstructive sleep apnea syndrome: a review.

BackgroundObstructive sleep apnea syndrome (OSAS) has a negative impact on health and behavior of millions of individuals worldwide. The pathogenesis of this disorder is a multifactorial process related to a variety of mechanisms, including selective activation of inflammatory response pathways. A number of inflammatory factors, such as IL-6, IL-8, and TNF-α, can be found in high concentrations in subjects with OSAS and may serve as biological markers of this disease. The concentration of these cytokines contributes to weight gain in patients with OSAS and can also modify the risk of obesity-related metabolic disorders, especially insulin resistance. Nevertheless, the mechanisms by which specific genes are associated with these processes are still poorly known. In addition to gene expression studies, investigations aiming at the identification of epigenetic factors associated with OSAS are still scarce in the literature. The documented data support the hypothesis that the molecular changes that mediate inflammatory response are important mechanisms in the pathogenesis of OSAS, sleepiness, insulin resistance, visceral obesity, and cardiovascular disease, perhaps by leading to a more severe OSAS. Often, systemic changes may not be detected in mild OSA; however, molecular changes, which are much more sensitive to the mechanisms of intermittent hypoxia and oxidative stress, may be present.Purpose This review aimed to show an updated view on the studies evaluating the genetic basis of inflammatory response in many aspects of OSAS and to highlight potential research areas not fully explored to date in this field.

Association of PPARα gene polymorphisms and lipid serum levels in a Brazilian elderly population

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a nuclear transcription factor strictly involved in lipid and lipoprotein metabolisms. Thus, PPARalpha gene polymorphisms have been investigated as cardiovascular risk factors. We aimed to investigate associations of L162V and intron 7G>C polymorphisms with common morbidities affecting a Brazilian elderly cohort as well as with lipid and protein serum levels. Genotyping was performed by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP), and allele frequencies were determined. In addition, we performed the linkage disequilibrium analysis. Descriptive statistics, logistic regression analysis, and Students t-test were used. Rare alleles for L162V and intron 7 G>C polymorphisms showed frequencies of 0.047 and 0.199, respectively. Our data showed that these polymorphisms were in linkage disequilibrium (p=0.0002). Intron 7 G>C polymorphism presented a tendency of association with neoplasia (p=0.053), and C allele was associated with higher HDL (p=0.010), lower triglycerides (p=0.001), and VLDL levels (p=0.003) compared to G allele. These data might suggest a protective role of intron 7 G>C polymorphism in the development of cardiovascular diseases and will help to clarify the importance of PPARalpha polymorphisms as key modulators of lipid metabolism in Brazilian population.

Telomere length as a marker of sleep loss and sleep disturbances: a potential link between sleep and cellular senescence

The identification of biological markers that allow the early diagnosis, or even the prevention of age-related diseases, is an important goal that is being actively pursued in the research community. Sleep is one of the physiological processes that is most affected by aging, and there is a strong relationship between age-related sleep alterations and diseases. Changes in cellular senescence and the linked changes in telomere length might be potential markers of age-related sleep changes. In this review, we present some of the most recent evidence showing that telomere length has been associated with sleep loss and sleep disturbances in cross-sectional and case-control studies. We also present insights into the cellular senescence mechanisms relating to changes in telomere length, and we suggest that this field lacks basic and clinical research studies, especially long-term longitudinal studies, which may bring opportunities to sleep researchers to investigate this relationship in more depth.

Association of APOE, GCPII and MMP9 polymorphisms with common diseases and lipid levels in an older adult/elderly cohort.

BACKGROUND AND AIMS The characterization of candidate gene polymorphisms in elderly populations is an important tool for the identification of risk factors for age-related diseases and conditions. We aimed to genotype the APOE polymorphisms (rs429358 and rs7412), rs61886492 (1561C>T) and rs202720 of GCPII gene and rs3918242 (-1562C>T) of MMP9 gene in an older-adult/elderly cohort from Cuiabá city, Mato Grosso Brazil as well as to characterize risk factors for morbidities and conditions affecting this cohort. METHODS The studied population consisted of 570 subjects from Cuiabá city, Brazil, who were subjected to clinical interviews and blood collection for laboratory examinations and DNA extraction. Restriction Fragment Length Polymorphism Polymerase Chain Reaction (RFLP-PCR), sequence-specific primer PCR (SSP-PCR) and TaqMan® allelic discrimination assay were used for genotyping. RESULTS The frequencies of APOE ε2 and ε4 were 6.6% and 14.8%, respectively, and the frequencies of GCPII rs61886492 T allele, GCPII rs202720 C allele and MMP9 rs3918242 T allele were, respectively, 3.0%, 26.6% and 10.1%. Significant associations between APOE ε2 allele with lower total cholesterol and LDL-cholesterol were found. In addition, MMP9 rs3918242 T allele was associated with higher LDL-cholesterol levels, suggesting a link between lipid metabolism alteration and cardiovascular disease. CONCLUSIONS The present findings contributed to characterize risk factors specific for the studied population and to better understand the molecular physiopathology of common morbidities and conditions affecting older-adult/elderly people.

Association of interleukin 1β polymorphisms and haplotypes with Alzheimer's disease

Our study aimed to associate IL-1β and IL-1RN polymorphisms with AD disease in comparison with elderly control group from São Paulo - Brazil. We genotyped 199 Alzheimers disease (AD) patients, 165 elderly control and 122 young control samples, concerning VNTR (IL-1RN) and -511C>T and -31T>C (IL-1β) polymorphisms. Our findings revealed that -511C/-31T/2-repetitions VNTR haplotype had a protective effect for AD when compared to EC (p=0.005), whereas -511C/-31C/1-repetition VNTR haplotype was associated as a risk factor for AD (p=0.021). Taken together, we may suggest that there is a relevant role of IL-1 genes cluster in AD pathogenesis in this Brazilian population.

Brain-derived neurotrophic factor gene polymorphism predicts interindividual variation in the sleep electroencephalogram.

Previous studies have suggested that brain‐derived neurotrophic factor (BDNF) participates in the homeostatic regulation of sleep. The objective of this study was to investigate the influence of the Val66Met functional polymorphism of the BDNF gene on sleep and sleep EEG parameters in a large population‐based sample. In total 337 individuals participating in the São Paulo Epidemiologic Sleep Study were selected for analysis. None of the participants had indications of a sleep disorder, as measured by full‐night polysomnography and questionnaire. Spectral analysis of the EEG was carried out in all individuals using fast Fourier transformation of the oscillatory signals for each EEG electrode. Sleep and sleep EEG parameters in individuals with the Val/Val genotype were compared with those in Met carriers (Val/Met and Met/Met genotypes). After correction for multiple comparisons and for potential confounding factors, Met carriers showed decreased spectral power in the alpha band in stage one and decreased theta power in stages two and three of nonrapid‐eye‐movement sleep, at the central recording electrode. No significant influence on sleep macrostructure was observed among the genotype groups. Thus, the Val66Met polymorphism seems to modulate the electrical activity of the brain, predicting interindividual variation of sleep EEG parameters. Further studies of this and other polymorphic variants in potential candidate genes will help the characterization of the molecular basis of sleep.