Disrupted Circadian Rest-Activity Cycles in Inflammatory Bowel Disease Are Associated With Aggressive Disease Phenotype, Subclinical Inflammation, and Dysbiosis

Morning light treatment for inflammatory bowel disease: a clinical trial

BACKGROUND

Inflammatory bowel disease (IBD) affects over 3 million Americans and has a relapsing and remitting course with up to 30% of patients experiencing exacerbations each year despite the availability of immune targeted therapies. An urgent need exists to develop adjunctive treatment approaches to better manage IBD symptoms and disease activity. Circadian disruption is associated with increased disease activity and may be an important modifiable treatment target for IBD. Morning light treatment, which advances and stabilizes circadian timing, may have the potential to improve IBD symptoms and disease activity, but no studies have explored these potential therapeutic benefits in IBD. Therefore, in this study, we aim to test the effectiveness of morning light treatment for patients with IBD.

METHODS

We will recruit sixty-eight individuals with biopsy-proven IBD and clinical symptoms and randomize them to 4-weeks of morning light treatment or 4-weeks of treatment as usual (TAU), with equivalent study contact. Patient-reported outcomes (IBD-related quality of life, mood, sleep), clinician-rated disease severity, and a biomarker of gastrointestinal inflammation (fecal calprotectin) will be assessed before and after treatment. Our primary objective will be to test the effect of morning light treatment versus TAU on IBD-related quality of life and our secondary objectives will be to test the effects on clinician-rated disease activity, depression, and sleep quality. We will also explore the effect of morning light treatment versus TAU on a biomarker of gastrointestinal inflammation (fecal calprotectin), and the potential moderating effects of steroid use, restless leg syndrome, and biological sex.

DISCUSSION

Morning light treatment may be an acceptable, feasible, and effective adjunctive treatment for individuals with active IBD suffering from impaired health-related quality of life.

TRIAL REGISTRATION

The study protocol was registered on ClinicalTrials.gov as NCT06094608 on October 23, 2023, before recruitment began on February 1, 2024.

Circadian immunity from bench to bedside: a practical guide

The immune system is built to counteract unpredictable threats, yet it relies on predictable cycles of activity to function properly. Daily rhythms in immune function are an expanding area of study, and many originate from a genetically based timekeeping mechanism known as the circadian clock. The challenge is how to harness these biological rhythms to improve medical interventions. Here, we review recent literature documenting how circadian clocks organize fundamental innate and adaptive immune activities, the immunologic consequences of circadian rhythm and sleep disruption, and persisting knowledge gaps in the field. We then consider the evidence linking circadian rhythms to vaccination, an important clinical realization of immune function. Finally, we discuss practical steps to translate circadian immunity to the patient's bedside.

Circadian rhythms in colonic function

A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.

Circadian rhythms, gut microbiota, and diet: Possible implications for health

AIMS

Over the past years, interest in chrono-nutrition has grown enormously as the fundamental role of circadian rhythms in regulating most physiological and metabolic processes has become clearer. Recently, the influence of circadian rhythms on the gut microbiota (GM) composition has also emerged, as more than half of the total microbial composition fluctuates rhythmically throughout the day. At the same time, other studies have observed that the GM itself synchronises the host's circadian biological clock through signals of a different nature. Therefore, it has been hypothesised that there is a two-way communication between the circadian rhythms of the host and the GM, but researchers have only just begun to identify some of its action mechanisms. The manuscript aim is, therefore, to gather and combine the latest evidence in the field of chrono-nutrition with the more recent research on the GM, in order to investigate their relationship and their potential impact on human health.

DATA SYNTHESIS

Considering current evidence, a desynchronization of circadian rhythms is closely associated with an alteration in the abundance and functionality of the gut microbiota with consequent deleterious effects on health, such as increased risk of numerous pathologies, including cardiovascular disease, cancer, irritable bowel disease, and depression. A key role in maintaining the balance between circadian rhythms and GM seems to be attributed to meal-timing and diet quality, as well as to certain microbial metabolites, in particular short-chain fatty acids.

CONCLUSIONS

Future studies are needed to decipher the link between the circadian rhythms and specific microbial patterns in relation to different disease frameworks.

Protective and therapeutic potential of melatonin against intestinal diseases: updated review of current data based on molecular mechanisms

INTRODUCTION

Intestinal diseases, a leading global cause of mortality and morbidity, carry a substantial socioeconomic burden. Small and large intestines play pivotal roles in gastrointestinal physiology and food digestion. Pathological conditions, such as gut dysbiosis, inflammation, cancer, therapy-related complications, ulcers, and ischemia, necessitate the urgent exploration of safe and effective complementary therapeutic strategies for optimal intestinal health.

AREAS COVERED

This article evaluates the potential therapeutic effects of melatonin, a molecule with a wide range of physiological actions, on intestinal diseases including inflammatory bowel disease, irritable bowel syndrome, colon cancer, gastric/duodenal ulcers and other intestinal disorders.

EXPERT OPINION

Due to anti-inflammatory and antioxidant properties as well as various biological actions, melatonin could be a therapeutic option for improving digestive disorders. However, more researches are needed to fully understand the potential benefits and risks of using melatonin for digestive disorders.

BMAL1/FOXA2-induced rhythmic fluctuations in IL-6 contribute to nocturnal asthma attacks

The circadian clock is closely associated with inflammatory reactions. Increased inflammatory cytokine levels have been detected in the airways of nocturnal asthma. However, the mechanisms that contribute to the nocturnal increase in inflammatory responses and the relationship with circadian clock remain unknown.

Methods

Inflammatory cytokine levels were measured in asthma patients with and without nocturnal symptoms. Allergic airway disease was induced in mice by ovalbumin (OVA), and different periods of light/dark cycles were used to induce circadian rhythm disorders. Serum shock was used to stimulate the rhythmic expression in human bronchial epidermal cells (16HBE). The expression and oscillation of circadian clock genes and inflammatory cytokines in 16HBE cells subjected to brain and muscle ARNT-like protein-1 (BMAL1) and Forkhead Box A2 (FOXA2) knockdown and treatment with a FOXA2 overexpression plasmid were assessed.

Results

Serum IL-6 was found to be significantly higher in asthmatic patients with nocturnal symptoms than those without nocturnal symptoms. The OVA-induced asthma model with a circadian rhythm disorder and 16HBE cells treated with serum shock showed an increase in IL-6 levels and a negative correlation with BMAL1 and FOXA2. The knockdown of BMAL1 resulted in a lower correlation between IL-6 and other rhythm clock genes. Furthermore, knockdown of the BMAL1 and FOXA2 in 16HBE cells reduced the expression and rhythmic fluctuations of IL-6.

Conclusions

Our findings suggest that there are increased IL-6 levels in nocturnal asthma resulting from inhibition of the BMAL1/FOXA2 signalling pathway in airway epithelial cells.

Circadian regulation of digestive and metabolic tissues

The circadian clock is a self-sustained molecular timekeeper that drives 24-h (circadian) rhythms in animals. The clock governs important aspects of behavior and physiology including wake/sleep activity cycles that regulate the activity of metabolic and digestive systems. Light/dark cycles (photoperiod) and cycles in the time of feeding synchronize the circadian clock to the surrounding environment, providing an anticipatory benefit that promotes digestive health. The availability of animal models targeting the genetic components of the circadian clock has made it possible to investigate the circadian clock's role in cellular functions. Circadian clock genes have been shown to regulate the physiological function of hepatocytes, gastrointestinal cells, and adipocytes; disruption of the circadian clock leads to the exacerbation of liver diseases and liver cancer, inflammatory bowel disease and colorectal cancer, and obesity. Previous findings provide strong evidence that the circadian clock plays an integral role in digestive/metabolic disease pathogenesis, hence, the circadian clock is a necessary component in metabolic and digestive health and homeostasis. Circadian rhythms and circadian clock function provide an opportunity to improve the prevention and treatment of digestive and metabolic diseases by aligning digestive system tissue with the 24-h day.