Alteration of gene expression in rat colon mucosa after exercise

Effects of Aerobic Treadmill Training on Oxidative Stress Parameters, Metabolic Enzymes, and Histomorphometric Changes in Colon of Rats with Experimentally Induced Hyperhomocysteinemia

The aim of this study was to investigate the effects of aerobic treadmill training regimen of four weeks duration on oxidative stress parameters, metabolic enzymes, and histomorphometric changes in the colon of hyperhomocysteinemic rats. Male Wistar albino rats were divided into four groups (n = 10, per group): C, 0.9% NaCl 0.2 mL/day subcutaneous injection (s.c.) 2x/day; H, homocysteine 0.45 µmol/g b.w./day s.c. 2x/day; CPA, saline (0.9% NaCl 0.2 mL/day s.c. 2x/day) and an aerobic treadmill training program; and HPA, homocysteine (0.45 µmol/g b.w./day s.c. 2x/day) and an aerobic treadmill training program. The HPA group had an increased level of malondialdehyde (5.568 ± 0.872 μmol/mg protein, p = 0.0128 vs. CPA (3.080 ± 0.887 μmol/mg protein)), catalase activity (3.195 ± 0.533 U/mg protein, p < 0.0001 vs. C (1.467 ± 0.501 U/mg protein), p = 0.0012 vs. H (1.955 ± 0.293 U/mg protein), and p = 0.0003 vs. CPA (1.789 ± 0.256 U/mg protein)), and total superoxide dismutase activity (9.857 ± 1.566 U/mg protein, p < 0.0001 vs. C (6.738 ± 0.339 U/mg protein), p < 0.0001 vs. H (6.015 ± 0.424 U/mg protein), and p < 0.0001 vs. CPA (5.172 ± 0.284 U/mg protein)) were detected in the rat colon. In the HPA group, higher activities of lactate dehydrogenase (2.675 ± 1.364 mU/mg protein) were detected in comparison to the CPA group (1.198 ± 0.217 mU/mg protein, p = 0.0234) and higher activities of malate dehydrogenase (9.962 (5.752-10.220) mU/mg protein) were detected in comparison to the CPA group (4.727 (4.562-5.299) mU/mg protein, p = 0.0385). Subchronic treadmill training in the rats with hyperhomocysteinemia triggers the colon tissue antioxidant response (by increasing the activities of superoxide dismutase and catalase) and elicits an increase in metabolic enzyme activities (lactate dehydrogenase and malate dehydrogenase). This study offers a comprehensive assessment of the effects of aerobic exercise on colonic tissues in a rat model of hyperhomocysteinemia, evaluating a range of biological indicators including antioxidant enzyme activity, metabolic enzyme activity, and morphometric parameters, which suggested that exercise may confer protective effects at both the physiological and morphological levels.

Influence of an Exergaming Training Program on Reducing the Expression of IL-10 and TGF-β in Cancer Patients

Objective: To evaluate the effect of exergaming in the plasma levels of adipokines (interleukin [IL]-1β, IL-6, IL-8, and tumor necrosis factor-alpha [TNF-α]), Th1 (IL-2, IL-12, and interferon gamma [IFN-γ]), Th2 (IL-4 and IL-33), Th17 (IL-17 and IL-23), and regulatory T (Treg) (IL-10 and transforming growth factor-beta [TGF-β]) in cancer patients undergoing treatment. Materials and Methods: We conducted a quasi-experimental control clinical trial using exergaming in all groups through the Xbox 360 Kinect™. The game used in this study was called Your Shape Fitness Evolved 2012. The volunteer participants played the game two to three times per week, for a total of 20 sessions. Forty-five volunteer participants were divided into 3 groups: cancer patients undergoing chemotherapy and/or radiotherapy treatment (chemotherapy and/or radiotherapy group CRG; n = 15); cancer patients who finished chemotherapy and/or radiotherapy treatment (cancer accompaniment group CAG; n = 15); and the control group (volunteers without a cancer diagnosis CG; n = 15). In the pre- and post-training period, all volunteers submitted to blood collection procedures using the enzyme-linked immunosorbent assay (ELISA). This test was used to obtain the levels of adipokines expression (IL-1β, IL-6, IL-8, and TNF-α) and the cytokine profiles Th1 (IL-2, IL-12, and IFN-γ), Th2 (IL-4 and IL-33), Th17 (IL-17 and IL-23), and Treg (IL-10 and TGF-β). Results: After exergaming, the CRG showed significant reductions in proinflammatory cytokines (IL-6: P < 0.05; IL-10: P = 0.038; TGF-β: P = 0.049) and for CAG (IL-10: P = 0.034), as well as a reduction in the expression of cytokines related to the action of T lymphocytes. Conclusion: Exergaming promoted changes in the expression of cytokine profiles IL-6, IL-10, and TGF-β, which correlated with the action profiles of CD4⁺ T lymphocytes.

Enriched environment on the intestinal mucosal barrier and brain-gut axis in rats with colorectal cancer

An enriched environment (EE) is an animal housing technique in which animals are given increased amounts of space, physical activity, and social interaction. Currently, researchers studying EE focus mainly on its effects within the context of neurological diseases. However, little is known about how EE affects the intestinal mucosal barrier. This study assessed the effects of EE on the intestinal mucosal barrier in rats with colorectal cancer. A rat model of 1,2-dimethylhydrazine (DMH)-induced colorectal cancer was used. The rats were housed in eight conditions for eight weeks: EE, large cages containing eight rats with stimulating objects; enlarged space and socially enriched conditions (ES), large cages containing eight rats; enlarged space and cognition enriched conditions (EC), large cages containing one rat with stimulating objects; enlarged space enriched conditions (E), large cages containing one rat; cognition and socially enriched conditions (CS), four to five rats housed in standard cages containing stimulating objects; cognition enriched conditions (C), rats housed individually in small-size cages containing stimulating objects; socially enriched conditions (S), standard cages containing four rats; and normal conditions (blank group, B). We determined the weight of each rat, measured the intestinal mucosa and plasma levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), interleukin 10 (IL-10), ghrelin, corticotropin-releasing factor (CRF), occludin, bacterial translocation (BT), and secretory immunoglobulin A (SIgA), and assessed the morphology of the intestinal mucosa. On the whole, the combination of cognitive stimulus and social support was better than the combination of three factors in maintenance of the intestinal mucosal immune barrier and brain–gut peptide. The combination of all three factors and combination of cognitive training and social support were more effective than any single factor. Future studies are needed to study the effects of an EE on body weight, brain–gut peptide, and the intestinal mucosa biological barrier.

Impact statement

An enriched environment (EE) is an animal housing technique where animals are given increased amounts of space, physical activity, and social interaction. Presently, researchers studying EEs focus mainly on their effects within the context of neurological diseases. However, little is known about how EEs affect the intestinal mucosal barrier. This study assessed the effects of an EE on the intestinal mucosal barrier in rats with colorectal cancer.

Epidemiology and biology of physical activity and cancer recurrence

Physical activity is emerging from epidemiologic research as a lifestyle factor that may improve survival from colorectal, breast, and prostate cancers. However, there is considerably less evidence relating physical activity to cancer recurrence and the biologic mechanisms underlying this association remain unclear. Cancer patients are surviving longer than ever before, and fear of cancer recurrence is an important concern. Herein, we provide an overview of the current epidemiologic evidence relating physical activity to cancer recurrence. We review the biologic mechanisms most commonly researched in the context of physical activity and cancer outcomes, and, using the example of colorectal cancer, we explore hypothesized mechanisms through which physical activity might intervene in the colorectal recurrence pathway. Our review highlights the importance of considering pre-diagnosis and post-diagnosis activity, as well as cancer stage and timing of recurrence, in epidemiologic studies. In addition, more epidemiologic research is needed with cancer recurrence as a consistently defined outcome studied separately from survival. Future mechanistic research using randomized controlled trials, specifically those demonstrating the exercise responsiveness of hypothesized mechanisms in early stages of carcinogenesis, are needed to inform recommendations about when to exercise and to anticipate additive or synergistic effects with other preventive behaviors or treatments.

Bone marrow-derived dendritic cells under influence of experimental breast cancer and physical activity

Immune cells are required in the immune response against tumours, although sometimes without success. The present study aimed to investigate dendritic cell (DC) maturation in animals with induced immunosuppression that were subjected to physical activity (PA). Immunosuppression was induced using 7,12-dimethyl-benzanthracene (DMBA). A total of 56 Balb/c mice were divided into four groups, including the control group, non-DMBA administered/PA group (GII), DMBA administered/non-PA group (GIII) and the DMBA administered/PA group (GIV). Bone marrow was removed from the leg bones following sacrifice. Bone marrow-derived DCs were stimulated to differentiate by granulocyte-macrophage colony-stimulating factor, interleukin (IL)-4 and tumour necrosis factor-α, after which the phenotype was assessed by flow cytometry and the cytokine profile was assessed using ELISAs. PA significantly increased the percentage of DCs in GII (55.38±2.63%) and GIV (50.1±3.1%) mice, as compared with GI (34.61±1.28%) and GIII (36.25±1.85%) mice (P<0.05). In addition, GIV mice showed a significantly higher level of cluster of differentiation (CD) 80⁺/CD86⁺ DCs (76.38±6.31%), as compared with GI (54.03±6.52%) and GIII (52.07±5.74%) mice (P<0.05). Furthermore, GIV mice showed a significantly higher level of CD80⁺/major histocompatibility complex class II double labelling (P<0.05), as compared with GIV (95.35±1.22%) and GIII (76.15±5.53%) mice. The expression of interferon-γ was significantly increased in GIV mice [5.89 (5.2-7.12)], as compared with GIII mice [2.75 (1.33-4.4)] (P<0.05). Similarly, the expression of IL-12 was markedly increased in GIV mice [1.27 (0.26-2.57)] compared with GIII mice [0.73 (0.44-1.47)], although the difference was not significant (P=0.063). The results of the present study suggested that PA was able to promote the maturation of DCs and their secretion of anti-tumour cytokines. Therefore, PA may emerge as a tool in immunotherapy.

Gene × environment interaction by a longitudinal epigenome-wide association study (LEWAS) overcomes limitations of genome-wide association study (GWAS)

The goal of genome-wide association studies is to identify SNPs unique to disease. It usually involves a single sampling from subjects' lifetimes. While primary DNA sequence variation influences gene-expression levels, expression is also influenced by epigenetics, including the 'somatic epitype' (G(SE)), an epigenotype acquired postnatally. While genes are inherited, and novel polymorphisms do not routinely appear, G(SE) is fluid. Furthermore, G(SE) could respond to environmental factors (such as heavy metals) and to differences in exercise, maternal care and dietary supplements - all of which postnatally modify oxidation or methylation of DNA, leading to altered gene expression. Change in epigenetic status may be critical for the development of many diseases. We propose a 'longitudinal epigenome-wide association study', wherein G(SE) are measured at multiple time points along with subjects' histories. This Longitudinal epigenome-wide association study, based on the 'dynamic' somatic epitype over the 'static' genotype, merits further investigation.

High fat mixed lipid diet modifies protective effects of exercise on 1,2 dimethylhydrazine induced colon cancer in rats

The aim of the present study was to evaluate the effect of long-term swimming exercise in conjunction with a high fat mixed lipid (HFML) diet on colon cancer (CC) development and lipid peroxidation in the large bowel. We used forty male Wistar rats, which were randomly divided into one control group and four cancer groups: sedentary and swimming groups fed a standard diet (LFCO) and sedentary and swimming groups fed an HFML diet. Corticosterone was determined during the experiment. After 6 months of swimming, the rats were sacrificed and blood, heart, liver, muscle and large bowel were taken for determining the activity of serum enzymes, antioxidant capacity and CC development. The results demonstrate that exercise has a protective role in CC development. Attenuated development of CC and increased levels of malondialdehyde (MDA) in the large bowel of exercised rats show that one of the protective effects of exercise on developing CC is induction of oxidative stress. However, in terms of the combined effects of dietary fat and exercise, our results indicate that the protective role of exercise on CC development is significantly depressed by an HFML diet. An HFML diet significantly reduced the protective influence of exercise on colon carcinogenesis in rats and affected the degree of peroxidation in the large bowel during exercise, as well as concentrations of serum enzymes (LDH, α-HBDH, CK, ALT and AST). Our results indicate that an HFML diet, which reflects the composition of a Western style diet, is a significant modifier of the protective effects of exercise on CC development in rats.

The "LEARn" (Latent Early-life Associated Regulation) model integrates environmental risk factors and the developmental basis of Alzheimer's disease, and proposes remedial steps

The neurodegenerative disorder Alzheimer's disease (AD) is the 6th leading cause of death in the USA. In addition to neurological and psychiatric symptoms, AD is characterized by deficiencies in S-adenylmethionine (SAM), vitamin B12, and folate. Deficiency in these nutrients has been shown to result in gene promoter methylation with upregulation of AD-associated genes. While some cases of AD are due to specific mutations in genes such as presenilin 1 (PSEN) and the amyloid-beta peptide precursor protein (APP), these familial AD (FAD) cases account for a minority of cases. The majority of genetic contribution consists of risk factors with incomplete penetrance. Several environmental risk factors, such as cholesterol and diet, head trauma, and reduced levels of exercise, have also been determined for AD. Nevertheless, the majority of risk for AD appears to be established early in life. We propose to explain this via the LEARn (Latent Early-life Associated Regulation) model. LEARn-AD (LAD) would be a "two-hit" disorder, wherein the first hit would occur due to environmental stress within the regulatory sequences of AD-associated genes, maintained by epigenetic changes such as in DNA methylation. This hit would most likely come in early childhood. The second hit could consist of further stress, such as head trauma, poor mid-life diet, or even general changes in expression of genes that occur later in life independent of any pathogenesis. Given that the primary risk for LAD would be maintained by DNA (hypo)methylation, we propose that long-term nutritional remediation based on the LEARn model, or LEARn-based nutritional gain (LEARnING), beginning early in life, would significantly reduce risk for AD late in life.

Induction of epigenetic alterations by dietary and other environmental factors

Dietary and other environmental factors induce epigenetic alterations which may have important consequences for cancer development. This chapter summarizes current knowledge of the impact of dietary, lifestyle, and environmental determinants of cancer risk and proposes that effects of these exposures might be mediated, at least in part, via epigenetic mechanisms. Evidence is presented to support the hypothesis that all recognized epigenetic marks (including DNA methylation, histone modification, and microRNA (miRNA) expression) are influenced by environmental exposures, including diet, tobacco, alcohol, physical activity, stress, environmental carcinogens, genetic factors, and infectious agents which play important roles in the etiology of cancer. Some of these epigenetic modifications change the expression of tumor suppressor genes and oncogenes and, therefore, may be causal for tumorigenesis. Further work is required to understand the mechanisms through which specific environmental factors produce epigenetic changes and to identify those changes which are likely to be causal in the pathogenesis of cancer and those which are secondary, or bystander, effects. Given the plasticity of epigenetic marks in response to cancer-related exposures, such epigenetic marks are attractive candidates for the development of surrogate endpoints which could be used in dietary or lifestyle intervention studies for cancer prevention. Future research should focus on identifying epigenetic marks which are (i) validated as biomarkers for the cancer under study; (ii) readily measured in easily accessible tissues, for example, blood, buccal cells, or stool; and (iii) altered in response to dietary or lifestyle interventions for which there is convincing evidence for a relationship with cancer risk.

The LEARn model: an epigenetic explanation for idiopathic neurobiological diseases

Neurobiological disorders have diverse manifestations and symptomology. Neurodegenerative disorders, such as Alzheimer's disease, manifest late in life and are characterized by, among other symptoms, progressive loss of synaptic markers. Developmental disorders, such as autism spectrum, appear in childhood. Neuropsychiatric and affective disorders, such as schizophrenia and major depressive disorder, respectively, have broad ranges of age of onset and symptoms. However, all share uncertain etiologies, with opaque relationships between genes and environment. We propose a 'Latent Early-life Associated Regulation' (LEARn) model, positing latent changes in expression of specific genes initially primed at the developmental stage of life. In this model, environmental agents epigenetically disturb gene regulation in a long-term manner, beginning at early developmental stages, but these perturbations might not have pathological results until significantly later in life. The LEARn model operates through the regulatory region (promoter) of the gene, specifically through changes in methylation and oxidation status within the promoter of specific genes. The LEARn model combines genetic and environmental risk factors in an epigenetic pathway to explain the etiology of the most common, that is, sporadic, forms of neurobiological disorders.

Physical activity in the prevention and treatment of colorectal carcinoma

BACKGROUND

Colorectal carcinoma is the most common type of tumor in Western countries. The risk of developing colorectal carcinoma depends both on genetic factors (familial predisposition) and on lifestyle-related factors such as body-mass index, level of physical activity, and nutritional behavior. Regular physical activity is important in primary prevention, and there is also evidence that the prognosis after treatment of a colorectal carcinoma can be improved by exercise.

METHODS

The PubMed database was searched for relevant articles that appeared in the last 10 years, and selected articles were evaluated.

RESULTS

Cross-sectional studies have shown that regular physical activity (ca. 7 hours of brisk walking per week) lowers the risk of colon carcinoma by 40%. Physical activity also improves the outcome of patients already diagnosed with colorectal carcinoma: for example, patients with advanced disease (UICC stage II or III) have been found to survive significantly longer if they perform 4 hours of brisk walking per week, or the equivalent degree of physical exercise.

CONCLUSIONS

Cross-sectional studies show that physically active persons are less likely to develop colorectal carcinoma than physically inactive persons, and that they have better outcomes in the event that they do develop the disease. The positive findings with respect to secondary prevention still need to be confirmed in interventional trials, but in primary prevention, at least, physical activity should be actively promoted, along with other beneficial lifestyle habits and screening measures.

Early-life events may trigger biochemical pathways for Alzheimer's disease: the "LEARn" model

Alzheimer's disease (AD), the most common form of dementia among the elderly, manifests mostly late in adult life. However, it is presently unclear when the disease process starts and how long the pathobiochemical processes take to develop. Our goal is to address the timing and nature of triggers that lead to AD. To explain the etiology of AD, we have recently proposed a "Latent Early-life Associated Regulation" (LEARn) model, which postulates a latent expression of specific genes triggered at the developmental stage. This model integrates both the neuropathological features (e.g., amyloid-loaded plaques and tau-laden tangles) and environmental factors (e.g., diet, metal exposure, and hormones) associated with the disease. Environmental agents perturb gene regulation in a long-term fashion, beginning at early developmental stages, but these perturbations do not have pathological results until significantly later in life. The LEARn model operates through the regulatory region (promoter) of the gene and by affecting the methylation status within the promoter of specific genes.