The aging brain: sleep, the circadian clock and exercise.

Aging is a multifactorial process likely stemming from damage accumulation and/or a decline in maintenance and repair mechanisms in the organisms that eventually determine their lifespan. In our review, we focus on the morphological and functional alterations that the aging brain undergoes affecting sleep and the circadian clock in both human and rodent models. Although both species share mammalian features, differences have been identified on several experimental levels, which we outline in this review. Additionally, we delineate some challenges on the preferred analysis and we suggest that a uniform route is followed so that findings can be smoothly compared. We conclude by discussing potential interventions and highlight the influence of physical exercise as a beneficial lifestyle intervention, and its effect on healthy aging and longevity. We emphasize that even moderate age-matched exercise is able to ameliorate several aging characteristics as far as sleep and circadian rhythms are concerned, independent of the species studied.

Effects of Chronic Dim-light-at-night Exposure on Sleep in Young and Aged Mice.

Dim-light-at-night (DLAN) exposure is associated with health problems, such as metabolic disruptions, immunological modulations, oxidative stress, sleep problems, and altered circadian timing. Neurophysiological parameters, including sleep patterns, are altered in the course of aging in a similar way. Here, we investigated the effect of chronic (three months) DLAN exposure (12 L:12 Dim-light, 75:5 lux) on sleep and the sleep electroencephalogram (EEG), and rest-activity behavior in young (6-month-old, n = 9) and aged (18- n = 8, 24-month-old, n = 6) C57BL/6J mice and compared with age-matched controls (n = 11, n = 9 and n = 8, respectively). We recorded the EEG and electromyogram continuously for 48-h and conducted a 6-h sleep-deprivation. A delay in the phase angle of entrainment of locomotor activity and daily vigilance state rhythms was apparent in mice following DLAN exposure, throughout the whole age spectrum, rendering sleep characteristics similar among the three age DLAN groups and significantly different from the age-matched controls. Notably, slow-wave-activity in NREM sleep (SWA, EEG power density in 0.5-4.0 Hz) was differentially altered in young and aged DLAN mice. Particularly, SWA increased as a function of age, which was further accentuated following DLAN exposure. However, this was not found in the young DLAN animals, which were characterized by the lowest SWA levels. Concluding, long-term DLAN exposure induced more pronounced alterations in the sleep architecture of young mice, towards an aging phenotype, while it enhanced age-associated sleep changes in the older groups. Our data suggest that irrespective of age, chronic DLAN exposure deteriorates sleep behavior and may consequently impact general health.

Chronic high-caloric diet accentuates age-induced sleep alterations in mice.

Obesity and sleep disturbances comprise major health problems which are likely interrelated. Diet-induced obesity in young mice has been demonstrated to lead towards an altered sleep homeostasis. In the current study, we investigated the effect of chronic (12 weeks) high-caloric diet (HCD, 45% fat) consumption on sleep and the sleep electroencephalogram (EEG) in young and older mice (6-month-old, n = 9; 18-month-old, n = 8 and 24-month-old, n = 4) and compared with age-matched controls on normal chow (n = 11, n = 9 and n = 9 respectively). Half of the 24-month-old mice did not cope well with HCD, therefore this group has a lower n and limited statistical power. We recorded EEG and the electromyogram for continuous 48-h and performed a 6-h sleep deprivation during the second day. In aged HCD fed mice (18 months old) compared to young, an aging effect was still evident, characterized by decreased waking and increased NREM sleep in the dark period, decreased REM sleep during the light period, as well as increased slow-wave-activity (SWA, EEG power in NREM sleep in 0.5-4.0 Hz). Additionally, aged HCD treated mice showed increased NREM sleep and decreased waking, compared to age-matched controls, denoting an enhanced aging phenotype in the sleep architecture. Notably, an overall increase was found in the slow component of SWA (0.5-2.5 Hz) in aged HCD fed mice compared to age-matched controls. Our data suggest that the effect of aging is the dominant variable irrespective of diet. However, a synergistic effect of aging and diet is noted indicating that chronic HCD consumption exacerbates age-associated sleep alterations.

Conventional vs. daylight photodynamic therapy for patients with actinic keratosis on face and scalp: 12-month follow-up results of a randomized, intra-individual comparative analysis.

INTRODUCTION: Daylight PDT (DLPDT) is a new PDT procedure. Several trials demonstrate that DLPDT achieves similar response rates with conventional PDT (CPDT) in the treatment of non-hyperkeratotic actinic keratoses (AKs) in a nearly painless way. It seems that DLPDT represents a more convenient and equally effective treatment modality. Data on long-term efficacy of DLPDT are limited. OBJECTIVE: To compare short- and long-term efficacy, safety and tolerability of DLPDT with that of CPDT in face and scalp AKs. METHODS: The study, an intra-individual right-left comparison study, was conducted in three centres in North, Center and South Greece. Eligible patients received either DLPDT or CPDT randomly allocated to alternate sides of face or scalp. Patients were evaluated at baseline, 3 and 12 months after treatment. Assessments included lesion response at 3 and 12 months, PDT-associated pain during PDT session, local skin reactions 3 days after treatment as well as patients' preference 3 months after treatment. RESULTS: A total of 46 patients completed the study. Three months after treatment, the overall lesion complete response rate was 78% for DLPDT and 80.6% for CPDT. At the 12-month follow-up, response rate decreased to 71.8% and 73.7% for DLPDT and CPDT accordingly. Regarding response based on lesion grade, response rates obtained in grade-I lesions were higher with DLPDT, while treatment with CPDT resulted to higher rates of cured grade-II lesions at both follow-up visits. Results were not supported by statistical significance. DLPDT was associated with significantly lower pain and reduced severity of local skin reactions. Patients' preference favoured DLPDT. CONCLUSIONS: Our study demonstrated that DLPDT is similar to CPDT in terms of long-term efficacy and recurrence rates in the treatment of face and scalp AKs. DLPDT demonstrated a better tolerability profile as it was associated with lower pain and less severe adverse events.

Saving space for less invasive direct-vision, mitral valve surgery with altered cannulation protocol.

Saving vital space in less invasive cardiac surgery is of great importance, especially in mitral valve surgery which is sometimes difficult, even with the full sternotomy approach. We present a modification of the venous cannulation protocol we use in less invasive, direct-vision mitral valve surgery through a half-lower partial sternotomy. The superior vena cava is drained with a right jugular vein cannula. For inferior vena cava drainage we use an oval venous cannula which is exteriorized through another small skin incision. These modifications, together with the use of a smaller diameter aortic cannula, provide vital space for surgical maneuvers through a small (810 cm) skin incision.