Chronodisruption and cardiovascular disease

Reestablishment of ad libitum feeding following partial food deprivation: Impact on locomotor activity, visceral fat, food intake, and circadian glycemic curve

Food deprivation has been associated with the development of metabolic pathologies. Few studies have explored the repercussions of a partial food deprivation following the reestablishment of an ad libitum diet. This study investigates the impact of a partial food deprivation (an 8-hour food intake restriction coupled with a 4-hour feeding window during the active phase) and the subsequent return to ad libitum feeding on the glycemic curve, food intake, and locomotor behavior. Wistar rats aged 45 days were subjected to 6 weeks of a partial food deprivation followed by 6 weeks of ad libitum feeding. Body weight, visceral fat, food intake, circadian glycemia, oral glucose tolerance, and locomotor activity were evaluated. It was found that the partial food deprivation resulted in the reduction of both the body weight and food intake; however, it increased visceral fat by 60%. Circadian glycemic values were altered at all intervals during the light phase, and glucose sensitivity improved at 60 minutes in the oral glucose tolerance test (OGTT). In the food-deprived group, the locomotor activity rhythm was reduced, with an observed delay in the peak of activity, reduction in total activity, and a decrease in the rhythmicity percentage. After the reestablishment of the ad libitum feeding, there was recovery of body weight, no difference in visceral fat, normalization of the food intake pattern, circadian glycemia, and oral glucose tolerance. Additionally, the return to ad libitum feeding restored locomotor activity, although the duration required for its complete recovery warrants further investigation. In conclusion, partial food deprivation induces physio-metabolic changes in rats, most of which are reversed after reestablishing ad libitum feeding.

Obesogenic environments as major determinants of a disease: It is time to re-shape our cities

Obesity rates are increasing in almost all high- and low-income countries, and population-based approaches are necessary to reverse this trend. The current global efforts are focused on identifying the root causes of obesity and developing effective methods for early diagnosis, screening, treatment, and long-term management, both at an individual and health system level. However, there is a relative lack of effective options for early diagnosis, treatment, and long-term management, which means that population-based strategies are also needed. These strategies involve conceptual shifts towards community- and environment-focused approaches. This review aimed to provide evidence on how environmental factors contribute to the risk of obesity and how reshaping cities can help slow down obesity prevalence rates and improve long-term management.

Brain washing and neural health: role of age, sleep, and the cerebrospinal fluid melatonin rhythm

The brain lacks a classic lymphatic drainage system. How it is cleansed of damaged proteins, cellular debris, and molecular by-products has remained a mystery for decades. Recent discoveries have identified a hybrid system that includes cerebrospinal fluid (CSF)-filled perivascular spaces and classic lymph vessels in the dural covering of the brain and spinal cord that functionally cooperate to remove toxic and non-functional trash from the brain. These two components functioning together are referred to as the glymphatic system. We propose that the high levels of melatonin secreted by the pineal gland directly into the CSF play a role in flushing pathological molecules such as amyloid-β peptide (Aβ) from the brain via this network. Melatonin is a sleep-promoting agent, with waste clearance from the CNS being highest especially during slow wave sleep. Melatonin is also a potent and versatile antioxidant that prevents neural accumulation of oxidatively-damaged molecules which contribute to neurological decline. Due to its feedback actions on the suprachiasmatic nucleus, CSF melatonin rhythm functions to maintain optimal circadian rhythmicity, which is also critical for preserving neurocognitive health. Melatonin levels drop dramatically in the frail aged, potentially contributing to neurological failure and dementia. Melatonin supplementation in animal models of Alzheimer's disease (AD) defers Aβ accumulation, enhances its clearance from the CNS, and prolongs animal survival. In AD patients, preliminary data show that melatonin use reduces neurobehavioral signs such as sundowning. Finally, melatonin controls the mitotic activity of neural stem cells in the subventricular zone, suggesting its involvement in neuronal renewal.