Mice held at an environmental photic cycle oscillating at their tau-like period length do not show the high-fat diet-induced obesity that develops under the 24-hour photic cycle

Sepiolite-Chitosan-Acetic Acid Biocomposite Attenuates the Development of Obesity and Nonalcoholic Fatty Liver Disease in Mice Fed a High-Fat Diet

Background; obesity and nonalcoholic fatty liver disease (NAFLD) reduce life expectancy; nonoperative interventions show poor results. Individually, chitosan (1% w/w), acetic acid (AA 0.3-6.5% w/w), and sepiolite clay (5% w/w) attenuate high-fat-diet-induced obesity (DIO) via reduced energy digestibility and increased energy expenditure. Objectives; therefore, we hypothesized that a chitosan-sepiolite biocomposite suspended in AA would attenuate DIO and NAFLD to a greater extent than AA alone via its more substantial adsorption of nonpolar molecules. Methods; we tested this dietary supplement in C57BL/6J mice fed a high-fat diet (HFD) compared to an unsupplemented HFD and an HFD supplemented with a bile acid sequestrant (cholestyramine) or standalone AA. Results; biocomposite supplementation reduced DIO gain by 60% and abolished hepatic liver accumulation, whereas standalone AA showed mild attenuation of DIO gain and did not prevent HFD-induced hepatic fat accumulation. The biocomposite intake was accompanied by a lower digestibility (-4 point %) counterbalanced by increased intake; hence, it did not affect energy absorption. Therefore, DIO attenuation was suggested to be related to higher energy expenditure, a phenomenon not found with AA alone, as supported by calculated energy expenditure using the energy balance method. Conclusions; these results support further investigation of the biocomposite's efficacy in attenuating obesity and NAFLD, specifically when applied with a restricted diet. Future studies are needed to determine this biocomposite's safety, mechanism of action, and efficacy compared to its components given separately or combined with other ingredients.

Eating Around the Clock: Circadian Rhythms of Eating and Metabolism

The time of day that we eat is increasingly recognized as contributing as importantly to overall health as the amount or quality of the food we eat. The endogenous circadian clock has evolved to promote intake at optimal times when an organism is intended to be awake and active, but electric lights and abundant food allow eating around the clock with deleterious health outcomes. In this review, we highlight literature pertaining to the effects of food timing on health, beginning with animal models and then translation into human experiments. We emphasize the pitfalls and opportunities that technological advances bring in bettering understanding of eating behaviors and their association with health and disease. There is great promise for restricting the timing of food intake both in clinical interventions and in public health campaigns for improving health via nonpharmacological therapies.

The REV-ERB Nuclear Receptors: Timekeepers for the Core Clock Period and Metabolism

REV-ERB nuclear receptors are potent transcriptional repressors that play an important role in the core mammalian molecular clock and metabolism. Deletion of both REV-ERBα and its largely redundant isoform REV-ERBβ in a murine tissue-specific manner have shed light on their specific functions in clock mechanisms and circadian metabolism. This review highlights recent findings that establish REV-ERBs as crucial circadian timekeepers in a variety of tissues, regulating overlapping and distinct processes that maintain normal physiology and protect from metabolic dysfunction.

REV-ERB nuclear receptors in the suprachiasmatic nucleus control circadian period and restrict diet-induced obesity

Circadian disruption, as occurs in shift work, is associated with metabolic diseases often attributed to a discordance between internal clocks and environmental timekeepers. REV-ERB nuclear receptors are key components of the molecular clock, but their specific role in the SCN master clock is unknown. We report here that mice lacking circadian REV-ERB nuclear receptors in the SCN maintain free-running locomotor and metabolic rhythms, but these rhythms are notably shortened by 3 hours. When housed under a 24-hour light:dark cycle and fed an obesogenic diet, these mice gained excess weight and accrued more liver fat than controls. These metabolic disturbances were corrected by matching environmental lighting to the shortened endogenous 21-hour clock period, which decreased food consumption. Thus, SCN REV-ERBs are not required for rhythmicity but determine the free-running period length. Moreover, these results support the concept that dissonance between environmental conditions and endogenous time periods causes metabolic disruption.