Intestinal tumours, colonic butyrate and sleep in exercised Min mice. Br J Nutr. 2010;104:355-363. [PMID: 20334709 DOI: 10.1017/s0007114510000528]

What is the gut feeling telling us about physical activity in colorectal carcinogenesis?

In the last decades, more efforts are focused on the prevention and treatment of malignant diseases, given the increase in all cancers incidence A lifestyle change, including healthy eating habits and regular physical activity, has significantly impacted colorectal cancer prevention. The effect of dose-dependent physical activity on mortality and recurrence rates of colorectal carcinoma has been unequivocally demonstrated in observational studies. However, clear recommendations are not available on the frequency, duration, and intensity of exercise in patients with colorectal cancer due to the lack of evidence in randomized clinical trials. Regarding pathophysiological mechanisms, the most plausible explanation appears to be the influence of physical activity on reducing chronic inflammation and insulin resistance with a consequent positive effect on insulin growth factor 1 signaling pathways.

Fecal microbiota transplantation confers beneficial metabolic effects of diet and exercise on diet-induced obese mice

Diet and exercise are conventional methods for controlling body weight and are linked to alterations in gut microbiota. However, the associations of diet, exercise, and gut microbiota in the control of obesity remain largely unknown. In the present study, using 16S rRNA amplicon sequencing and fecal microbiota transplantation (FMT), normal fat diet (NFD), exercise and their combination resulted in improved metabolic profiles in comparison to sedentary lifestyle with high fat diet (HFD). Moreover, diet exerted more influence than exercise in shaping the gut microbiota. HFD-fed mice receiving FMT from NFD-exercised donors not only showed remarkably reduced food efficacy, but also mitigated metabolic profiles (p < 0.05). The transmissible beneficial effects of FMT were associated with bacterial genera Helicobacter, Odoribacter and AF12 and overrepresentation of oxidative phosphorylation and glycolysis genes. Our findings demonstrate that the beneficial effects of diet and exercise are transmissible via FMT, suggesting a potential therapeutic treatment for obesity.

Influence of Exercise on Inflammation in Cancer: Direct Effect or Innocent Bystander?

We propose the hypothesis that the benefits of exercise on inflammation in cancer are a result of a direct effect on inflammatory cytokines, including interleukin-6, tumor necrosis factor-α, and monocyte chemoattractant protein 1, that are critical for cancer growth as well as a bystander effect of the established relationship between exercise and cancer.

Insights into the role of the microbiome in obesity and type 2 diabetes

The worldwide prevalence of obesity and type 2 diabetes mellitus (T2DM) continues to rise at an alarming pace. Recently the potential role of the gut microbiome in these metabolic disorders has been identified. Obesity is associated with changes in the composition of the intestinal microbiota, and the obese microbiome seems to be more efficient in harvesting energy from the diet. Lean male donor fecal microbiota transplantation (FMT) in males with metabolic syndrome resulted in a significant improvement in insulin sensitivity in conjunction with an increased intestinal microbial diversity, including a distinct increase in butyrate-producing bacterial strains. Such differences in gut microbiota composition might function as early diagnostic markers for the development of T2DM in high-risk patients. Products of intestinal microbes such as butyrate may induce beneficial metabolic effects through enhancement of mitochondrial activity, prevention of metabolic endotoxemia, and activation of intestinal gluconeogenesis via different routes of gene expression and hormone regulation. Future research should focus on whether bacterial products (like butyrate) have the same effects as the intestinal bacteria that produce it, in order to ultimately pave the way for more successful interventions for obesity and T2DM. The rapid development of the currently available techniques, including use of fecal transplantations, has already shown promising results, so there is hope for novel therapies based on the microbiota in the future.

Sleep, immunity and inflammation in gastrointestinal disorders

Sleep disorders have become a global issue, and discovering their causes and consequences are the focus of many research endeavors. An estimated 70 million Americans suffer from some form of sleep disorder. Certain sleep disorders have been shown to cause neurocognitive impairment such as decreased cognitive ability, slower response times and performance detriments. Recent research suggests that individuals with sleep abnormalities are also at greater risk of serious adverse health, economic consequences, and most importantly increased all-cause mortality. Several research studies support the associations among sleep, immune function and inflammation. Here, we review the current research linking sleep, immune function, and gastrointestinal diseases and discuss the interdependent relationship between sleep and these gastrointestinal disorders. Different physiologic processes including immune system and inflammatory cytokines help regulate the sleep. The inflammatory cytokines such as tumor necrosis factor, interleukin-1 (IL-1), and IL-6 have been shown to be a significant contributor of sleep disturbances. On the other hand, sleep disturbances such as sleep deprivation have been shown to up regulate these inflammatory cytokines. Alterations in these cytokine levels have been demonstrated in certain gastrointestinal diseases such as inflammatory bowel disease, gastro-esophageal reflux, liver disorders and colorectal cancer. In turn, abnormal sleep brought on by these diseases is shown to contribute to the severity of these same gastrointestinal diseases. Knowledge of these relationships will allow gastroenterologists a great opportunity to enhance the care of their patients.

Identifying molecular targets of lifestyle modifications in colon cancer prevention

One in four deaths in the United States is cancer-related, and colorectal cancer (CRC) is the second leading cause of cancer-associated deaths. Screening strategies are utilized but have not reduced disease incidence or mortality. In this regard, there is an interest in cancer preventive strategies focusing on lifestyle intervention, where specific etiologic factors involved in cancer initiation, promotion, and progression could be targeted. For example, exposure to dietary carcinogens, such as nitrosamines and polycyclic aromatic hydrocarbons influences colon carcinogenesis. Furthermore, dietary deficiencies could alter sensitivity to genetic damage and influence carcinogen metabolism contributing to CRC. High alcohol consumption increases the risk of mutations including the fact that acetaldehyde, an ethanol metabolite, is classified as a group 1 carcinogen. Tobacco smoke exposure is also a risk factor for cancer development; approximately 20% of CRCs are associated with smoking. Additionally, obese patients have a higher risk of cancer development, which is further supported by the fact that physical activity decreases CRC risk by 55%. Similarly, chronic inflammatory conditions also increase the risk of CRC development. Moreover, the circadian clock alters digestion and regulates other biochemical, physiological, and behavioral processes that could influence CRC. Taken together, colon carcinogenesis involves a number of etiological factors, and therefore, to create effective preventive strategies, molecular targets need to be identified and beleaguered prior to disease progression. With this in mind, the following is a comprehensive review identifying downstream target proteins of the above lifestyle risk factors, which are modulated during colon carcinogenesis and could be targeted for CRC prevention by novel agents including phytochemicals.

Sleep duration and incidence of colorectal cancer in postmenopausal women

Background:

Sleep duration is dependent on circadian rhythm that controls a variety of key cellular functions. Circadian disruption has been implicated in colorectal tumorigenesis in experimental studies. We prospectively examined the association between sleep duration and risk of colorectal cancer (CRC).

Methods:

In the Women’s Health Initiative Observational Study, 75 828 postmenopausal women reported habitual sleep duration at baseline 1993–1998. We used Cox proportional hazards regression model to estimate the hazard ratio (HR) of CRC and its associated 95% confidence interval (CI).

Results:

We ascertained 851 incident cases of CRC through 2010, with an average 11.3 years of follow-up. Compared with 7 h of sleep, the HRs were 1.36 (95% CI 1.06–1.74) and 1.47 (95% CI 1.10–1.96) for short (⩽5 h) and long (⩾9 h) sleep duration, respectively, after adjusting for age, ethnicity, fatigue, hormone replacement therapy (HRT), physical activity, and waist to hip ratio. The association was modified by the use of HRT (P-interaction=0.03).

Conclusion:

Both extreme short and long sleep durations were associated with a moderate increase in the risk of CRC in postmenopausal women. Sleep duration may be a novel, independent, and potentially modifiable risk factor for CRC.

Combined lifestyle factors and risk of incident colorectal cancer in a Chinese population

A body of research links dietary intake, alcohol consumption, smoking, physical activity, body mass index (BMI), and possibly sleep patterns with colorectal cancer risk. However, little research has examined the association of the combination of these lifestyle factors with incidence of colorectal cancer, especially in non-Western populations. A protective lifestyle factor index of these six aforementioned factors was created and examined in relation to risk of developing colorectal cancer. This study is a prospective observational study of 50,466 Chinese men and women in Singapore ages 45 to 74 years during enrollment in the Singapore Chinese Health Study in 1993-1998 and followed up through 2007. The main outcome measures were standardized rates and HRs of incident colorectal cancer. The protective levels of each lifestyle factor were independently associated with reduced age- and sex-standardized incidence rates of colon cancer. When all the factors were combined into a single protective lifestyle factor index, there was a strong, monotonic decrease in incidence rate of colon cancer with an increasing score. Relative to participants with an index score of 0 to 3, the HRs (95% confidence intervals) of colon cancer for an index score of 4, 5, 6, 7, 8, and 9/10 were 0.58 (0.35-0.95), 0.56 (0.36-0.86), 0.50 (0.33-0.76), 0.43 (0.28-0.66), 0.39 (0.25-0.63), and 0.25 (0.12-0.54; P(trend) < 0.0001). The results were consistent by sex. Conversely, there was no association with rectal cancer risk. An increasing protective lifestyle factor index score is associated with a marked decreased risk of developing colon cancer in Chinese men and women.

Gut bacteria in health and disease: a survey on the interface between intestinal microbiology and colorectal cancer

A healthy human body contains at least tenfold more bacterial cells than human cells and the most abundant and diverse microbial community resides in the intestinal tract. Intestinal health is not only maintained by the human intestine itself and by dietary factors, but is also largely supported by this resident microbial community. Conversely, however, a large body of evidence supports a relationship between bacteria, bacterial activities and human colorectal cancer. Symbiosis in this multifaceted organ is thus crucial to maintain a healthy balance within the host-diet-microbiota triangle and accordingly, changes in any of these three factors may drive a healthy situation into a state of disease. In this review, the factors that sustain health or drive this complex intestinal system into dysbiosis are discussed. Emphasis is on the role of the intestinal microbiota and related mechanisms that can drive the initiation and progression of sporadic colorectal cancer (CRC). These mechanisms comprise the induction of pro-inflammatory and pro-carcinogenic pathways in epithelial cells as well as the production of (geno)toxins and the conversion of pro-carcinogenic dietary factors into carcinogens. A thorough understanding of these processes will provide leads for future research and may ultimately aid in development of new strategies for CRC diagnosis and prevention.

Effects of physical activity on cancer prevention

Results of most epidemiological and laboratory studies suggest an inverse relationship between regular exercise and the risk of certain malignancies, such as intestinal, colon, pancreatic, breast, lung, skin, mammary, endometrial, and prostate cancer. However, physical activity can have different influence on carcinogenesis, depending on energy supply and the age of the subject as well as strength, frequency, and length of exercise. The biochemical and molecular basis of the interaction between aerobic physical activity and tumorigenic processes remains poorly understood. Physical activity may generate reactive oxygen species (ROS) to a different extent. Mild oxidative stress caused by moderate physical activity can activate cellular stress response signaling and potentiate cellular antioxidant defense capacity. However, accumulation of relatively large amounts of ROS as a consequence of exhaustive exercise can either directly damage DNA, causing mutation, or promote tumorigenesis by activating proinflammatory signaling. This review highlights the effects of physical activity on various malignancies in the context of redox status modulated during exercise.

Head and neck manifestations of neurofibromatosis

Neurofibromatosis is a neurocutaneous systemic disease that occurs in 1:2500 to 3300 live births. Prevalence figures have shown it to be as common as cystic fibrosis or Down's syndrome and more than twice as common as muscular dystrophy. In this study, our experience with 257 cases of neurofibromatosis seen since 1972 is reviewed. Intracranial, bony, and extracranial anomalies are described in the 223 patients (87%) who presented with, or ultimately developed, head and neck manifestations of the disease. The most common intracranial tumor was optic glioma, found in 35 patients (14%), 19 younger than 10 years of age. Acoustic neuromas were diagnosed in eight individuals (3%) and were bilateral in three. The most common skull anomaly was macrocephaly, noted 78 times (30%). Absence of the sphenoid wing occurred in 11 patients (4%) and 19 others (7%) had facial asymmetry due to other skull abnormalities. Extracranial manifestations included neurofibromas of the plexiform and nonplexiform type, Lisch nodules, and cafe-au-lait spots.