Epigenetic alterations-The silent indicator for early aging and age-associated health-risks.

Aging is the process of gradual physiological deterioration till death and this process perpetually reduce the functionality of an individual. To address the rationale and provide geriatric care, the constant target of geroscience is to identify reliable biomarkers for aging. Over the past decades, diversified advancements in epigenetic studies crescively support the fact that the accumulation of epigenetic changes accompanies the process of aging. A growing number of studies have suggested that alterations occur through three fundamental mechanisms like methylation of DNA, histone protein modification, and production of non-coding microRNAs. Each of these changes occurs silently and provokes alterations in the circumstantial expression of genetic material without altering the underlying gene sequences. The changes in gene expression due to epigenetic alterations are suggested to be the cause of early aging and the onset of age-related health risks. This review would attempt to give an integrated overview of epigenetic changes related to aging and age-associated health risks. This review also discussed epigenomes influencing early aging and factors modulating it. Since epigenetic changes are reversible, early identification of epigenetic markers can be a hope for future geriatric medicine. Finally, this review emphasizes the identification of blood-based epigenetic biomarkers in order to enlighten the future scope for therapeutic intervention to slow down the aging process.

Evaluation of sympathetic sudomotor responses to auditory stimuli in children with autism spectrum disorders.

AIM AND OBJECTIVE: Autism spectrum disorder (ASD) being a complex neurological and developmental disorder is also associated with autonomic nervous system dysfunction. Sudomotor nerve function is one highly sensitive index of sympathetic cholinergic activity and can be evaluated by measuring sympathetic skin response (SSR) to various stimuli. Studies reporting SSR to auditory stimulus among ASDs are limited and to the extent of our knowledge not assessed in the Indian scenario. The objective of the study was to assess and compare sympathetic sudomotor activity by evaluating SSR to auditory stimuli in children with and without ASDs. MATERIALS AND METHODS: A total of eighty individuals were enrolled in the study, including forty children with ASD and forty typically developing (TD) children. SSR to auditory stimulus was assessed using a digitized data acquisition unit in a soundproof room, maintained at 23°C. SSR indices such as latent period (s), amplitude (mv), and habituation were analyzed and compared using appropriate statistical tests between the groups. P < 0.05 was considered statistically significant. RESULTS: Habituation for SSR was statistically significantly lower (P < 0.001) in children with ASD (0.43 [0.21, 0.61]) compared to TD children (0.78 [0.65, 0.95]). Latent period was also statistically significantly higher in children with ASD (1.67 [1.37, 2.02]) compared to TD children (1.41 [1.2, 1.72]). However, there was no significant difference in amplitude values between the groups. CONCLUSIONS: Children with ASDs exhibited slower habituation of SSR to auditory stimuli compared to healthy controls. This slower habituation process might be due to the persistent predominant state of sympathetic nerves, which, in turn, contributes to the atypical emotional and behavioral traits prevailing in ASDs.

Comparison of Physiological and Biochemical Autonomic Indices in Children with and without Autism Spectrum Disorders.

Background and objectives: Autism Spectrum Disorder (ASD) is a complex neuro-developmental disorder and it has been suggested that symptoms of ASD are associated with neural networks that regulate the Autonomic Nervous System (ANS). However, the nature of autonomic atypicalities in ASDs remain largely unknown. Measures like Heart Rate Variability (HRV) and urinary Vanillylmandelic Acid (VMA) estimation are sensitive and non-invasive physiological and biochemical indicators of autonomic nervous activity. This study aimed to compare the physiological and biochemical autonomic indices in children with and without ASD. Materials and Methods: In this case-control study, 40 children with autism and 40 Typically Developing (TD) children were recruited. Measures of physiological autonomic index were assessed by the analysis of short term HRV, and the urinary levels of VMA estimation was used as a biochemical autonomic index. Results: Cardiac sympathetic activity assessed by Low Frequency (nu) of HRV was significantly higher in the ASD group in comparison with the TD group (p = 0.006). On the contrary, both the High Frequency (abs) and (nu) of HRV were found to be significantly lower in autistic children (p = 0.034 and p = 0.000) than controls. Autistic children also exhibited a significantly higher level (p = 0.049) of VMA concentration compared to TD children. Conclusion: The study concludes that children with ASD exhibit lower cardio-vagal activity as measured by HRV and increased sympathetic activity as assessed by urinary VMA compared to that of TD children. The core autistic symptoms exhibited by children with ASD could be due to the differences in baseline arousal or stress which might be associated with autonomic dysfunction. Further studies are needed to examine the association of this autonomic dysregulation with ASD symptoms and comorbidities.

Comparison of cardiac autonomic activity between pre and post menopausal women using heart rate variability.

Ageing is associated with a decline in short-term indexes of heart rate variability (HRV). But there is little evidence regarding the extent to which age-related changes in HRV depend on simultaneous changes in levels of estrogen and body composition as it occurs from pre menopausal state to postmenopausal state. The purpose of this study was (i) to compare HRV between pre and postmenopausal women, (ii) to determine whether difference in age, estrogen level and body composition could account for the difference in HRV between these two groups. HRV was assessed using spectral analysis and estrogen level was estimated using radioimmunoassay technique. The body composition, in terms of percent fat, was assessed using measurement of skin fold thickness. Data was analyzed both before and after adjusting for age, estrogen level and body composition. It was found that the total power, high frequency (HF) and the low frequency (LF) power spectrum of HRV in absolute units were significantly lower (P < 0.001) in postmenopausal women compared to that of premenopausal women. Postmenopausal women had significantly lower HF (P < 0.01) and higher LF (P < 0.01) when expressed in normalized units. The ratio of LF/HF, the index of sympathovagal balance was significantly higher (P < 0.01) among postmenopausal women. Analysis after adjusting for age, revealed that age was one of the important confounder, responsible for the differences in all the components of power spectrum between the two study groups. Difference in estrogen level contributed for the difference in relative values of HF and LF components of HRV. Difference in body composition did not explain the difference in HRV between the groups. The study concludes that both ageing and declined estrogen levels are associated with the autonomic alterations seen among postmenopausal women.