Intermittent fasting prompted recovery from dextran sulfate sodium-induced colitis in mice

Intermittent fasting alleviates IMQ-induced psoriasis-like dermatitis via reduced γδT17 and monocytes in mice

Psoriasis is a chronic immune mediated inflammatory skin disease with systemic manifestations. It has been reported that caloric restriction could improve severity of psoriasis patients. However, the mechanism of intermittent fasting effects on psoriasis has not been investigated. Caloric restriction is known to reduce the number of circulating inflammatory monocytes in a CCL2-dependent manner. However, it is still unknown whether caloric restriction can improve psoriasis by regulating monocytes through CCL2. In this study, we used imiquimod (IMQ)-induced psoriasis-like mouse model to explore the effects and the mechanisms of intermittent fasting on psoriasis-like dermatitis. We found that intermittent fasting could significantly improve IMQ-induced psoriasis-like dermatitis, and reduce the number of γδT17 cells and IL-17 production in draining lymph nodes and psoriatic lesion via inhibiting proliferation and increasing death of γδT17 cells. Furthermore, intermittent fasting could significantly decrease monocytes in blood, and this was associated with decreased monocytes, macrophages and DC in psoriasis-like skin inflammation. Reduced monocytes in circulation and increased monocytes in BM of fasting IMQ-induced psoriasis-like mice is through reducing the production of CCL2 from BM to inhibit monocyte egress to the periphery. Our above data shads light on the mechanisms of intermittent fasting on psoriasis.

Silibinin, a potential fasting mimetic, inhibits hepatocellular carcinoma by triggering extrinsic apoptosis

Fasting, without inducing malnutrition, has been shown to have various beneficial effects, including the inhibition of tumor initiation and progression. However, prolonged fasting poses challenges for many cancer patients, particularly those in intermediate and terminal stages. Thus, there is an urgent need for the development of fasting mimetics which harness the protective effects of fasting but more suitable for patients. In this study, we first highlighted the pivotal role of silibinin in AMP-activated protein kinase (AMPK) pathway and may serve, as a potential fasting mimetic via screening hepatoprotective drugs. Further metabolic analysis showed that silibinin inhibited the adenosine triphosphate (ATP) levels, glucose uptake and diminished glycolysis process, which further confirmed that silibinin served as a fasting mimetic. In addition, fasting synergized with silibinin, or used independently, to suppress the growth of hepatocellular carcinoma (HCC) in vivo. Mechanistically, silibinin upregulated death receptor 5 (DR5) through AMPK activation, and thus promoting extrinsic apoptosis and inhibiting HCC growth both in vitro and in vivo. Inhibition of AMPK using small interfering RNA (siRNA) or compound C, an AMPK inhibitor, significantly attenuated the upregulation of DR5 and the apoptotic response induced by silibinin. These findings suggest that silibinin holds promise as a fasting mimetic and may serve as an adjuvant drug for HCC treatment.

Restrictive diets have a beneficial impact on dextran sodium sulfate-induced colitis in male mice

BACKGROUND

Previously, we assessed the impact of restrictive diets, including caloric restriction (CR), intermittent fasting (IF), or fasting-mimicking diet (FMD), on a healthy gastrointestinal tract. We revealed that each of the diets shows anti-inflammatory outcomes.

OBJECTIVE

The current study aimed to verify the diets' applicability in treating colitis.

METHODS

We exposed a mouse model with mild chronic dextran sodium sulfate (DSS)-induced colitis to ad libitum control feeding, CR, IF, or FMD. The collected samples were analyzed for markers of inflammation.

RESULTS

The diets reduced DSS-triggered increases in spleen weight and myeloperoxidase (MPO) activity. Diet intervention also influenced occludin levels, small intestine morphology, as well as cytokine and inflammatory gene expression, mainly in the mucosa of the proximal colon. The diets did not reverse DSS-enhanced gut permeability and thickening of the colon muscularis externa. Concerning inflammatory gene expression, the impact of DSS and the dietary intervention was limited to the colon as we did not measure major changes in the jejunum mucosa, Peyer's patches, and mesenteric lymph nodes. Further, rather modest changes in the concentration of intestinal bile acids were observed in response to the diets, whereas taurine and its conjugates levels were strongly affected.

CONCLUSIONS

Despite the differences in the dietary protocol, the tested diets showed very similar impacts and, therefore, may be interchangeable when aiming to reduce inflammation in the colon. However, FMD showed the most consistent beneficial impact.

Time-restricted feeding ameliorates dextran sulfate sodium-induced colitis via reducing intestinal inflammation

Time-restricted feeding (TRF) is an emerging dietary intervention that improves metabolic disorders such as obesity, insulin resistance and dyslipidemia. Inflammatory bowel disease (IBD) is a chronic inflammatory disorder affecting the gastrointestinal tract, where nutrition plays an important role in its pathogenesis. Although numerous strategies of nutritional intervention have been reported, whether TRF can improve IBD has been elusive. In this study, we investigated the effect of two cycles of 7-day TRF intervention in a dextran sulfate sodium-induced IBD mouse model. We found that TRF was able to reduce the disease activity index and ameliorate the IBD-associated symptoms, as well as increase the number of colonic crypts and decrease the histological score in the colon. Furthermore, TRF lowered the percentage of CD4⁺ T cells in the peripheral blood and mesenteric lymph node, and increased the number of CD4⁺CD25⁺ T cells in the mesenteric lymph nodes. Additionally, TRF reduced the infiltration of leukocytes and macrophages around the crypt base in the colon. However, unlike the intermittent caloric restriction with fasting-mimicking diet, TRF was not able to increase the markers of progenitor and cell proliferation in the colon. Collectively, these results demonstrated that TRF is able to improve IBD in mice via reduction in intestinal inflammation.

Intermittent Fasting Alleviates Risk Markers in a Murine Model of Ulcerative Colitis by Modulating the Gut Microbiome and Metabolome

Clinical trials have demonstrated the health benefits of intermittent fasting (IF). However, the potential mechanism of IF in alleviating dextran sulfate sodium (DSS)-induced colitis is not fully understood. The present study was mainly designed to explore the dynamic changes in the gut microbiota and metabolome after short-term (2 weeks) or long-term (20 weeks) IF and therefore clarify the potential mechanisms by which IF ameliorates DSS-induced colitis in a murine model. Thirty-two C57BL/6 male mice were equally divided into four groups and underwent IF intervention for 2 weeks (SIF group, n = 8), 20 weeks (LIF group, n = 8), or were allowed free access to food for 2 weeks (SAL group, n = 8) or 20 weeks (LAL group, n = 8). The thirty-two C57BL/6 male mice were accepted for the diet intervention of 2 weeks of IF or fed ad libitum. Colitis was induced by drinking 2% DSS for 7 days. Our findings showed that short-term IF prominently elevates the abundance of Bacteroides, Muibaculum and Akkermansia (p < 0.001, p < 0.001, p < 0.001, respectively), and decreased the abundance of Ruminiclostridium (p < 0.05). Long-term IF, however, decreased the abundance of Akkermansia and obviously increased the abundance of Lactobacillus (p < 0.05, p < 0.001, respectively). Metabolites mainly associated with nucleoside, carbohydrate, amino acid, bile acid, fatty acid, polyol, steroid and amine metabolism were identified in the faeces using untargeted GC/MS. In particular, inosine was extremely enriched after short-term IF and long-term IF (p < 0.01, p < 0.01, respectively); butyrate, 2-methyl butyric acid and valeric acid were significantly decreased after short-term IF (p < 0.001, p < 0.001, p < 0.01, respectively); and 2-methyl butyric acid was significantly increased after long-term IF (p < 0.001). The abundance of lithocholic acid (LCA), one of the secondary bile acids, increased significantly after short-term and long-term IF based on UPLC−MS/MS (p < 0.001, p < 0.5, respectively). Of note, IF markedly mitigated DSS-induced acute colitis symptoms and down-regulated pro-inflammatory cytokines IL-1α, IL-6, keratinocyte-derived chemokine (KC) and G-CSF levels in the serum (p < 0.01, p < 0.001, p < 0.05, p < 0.001, respectively). Furthermore, a correlation analysis indicated that the disease activity index (DAI) score and serum levels of IL-1α, IL-6, KC, and G-CSF were negatively correlated with the relative abundance of Akkermansia and the faecal metabolites LCA and inosine. This study confirmed that IF altered microbiota and reprogramed metabolism, which was a promising development in the attempt to prevent DSS-induced colitis. Moreover, our findings provide new insights regarding the correlations among the mucosal barrier dysfunction, metabolome, and microbiome.

A Comparison of the Impact of Restrictive Diets on the Gastrointestinal Tract of Mice

The rate of gut inflammatory diseases is growing in modern society. Previously, we showed that caloric restriction (CR) shapes gut microbiota composition and diminishes the expression of inflammatory factors along the gastrointestinal (GI) tract. The current project aimed to assess whether prominent dietary restrictive approaches, including intermittent fasting (IF), fasting-mimicking diet (FMD), and ketogenic diet (KD) have a similar effect as CR. We sought to verify which of the restrictive dietary approaches is the most potent and if the molecular pathways responsible for the impact of the diets overlap. We characterized the impact of the diets in the context of several dietary restriction-related parameters, including immune status in the GI tract; microbiota and its metabolites; bile acids (BAs); gut morphology; as well as autophagy-, mitochondria-, and energy restriction-related parameters. The effects of the various diets are very similar, particularly between CR, IF, and FMD. The occurrence of a 50 kDa truncated form of occludin, the composition of the microbiota, and BAs distinguished KD from the other diets. Based on the results, we were able to provide a comprehensive picture of the impact of restrictive diets on the gut, indicating that restrictive protocols aimed at improving gut health may be interchangeable.

Calorie Restriction as a New Treatment of Inflammatory Diseases

Immoderate calorie intake coupled with a sedentary lifestyle are major determinants of health issues and inflammatory diseases in modern society. The balance between energy consumption and energy expenditure is critical for longevity. Excessive energy intake and adiposity cause systemic inflammation, whereas calorie restriction (CR) without malnutrition, exerts a potent anti-inflammatory effect. The objective of this review was to provide an overview of different strategies used to reduce calorie intake, discuss physiological mechanisms by which CR might lead to improved health outcomes, and summarize the present knowledge about inflammatory diseases. We discuss emerging data of observational studies and randomized clinical trials on CR that have been shown to reduce inflammation and improve human health.

An appraisal of the gut health modulatory effects of a calf faecal-origin probiotic Lactobacillus salivarius CPN60 using Wistar rats with dextran sulfate sodium-induced colitis

BACKGROUND

Probiotics of varied origins are being developed for augmenting the gut health of human and animals. The present study aimed to evaluate the effect of a calf-origin probiotic supplement on the gut health of Wistar rats for both healthy and colitis conditions.

RESULTS

Forty-eight rats were randomly distributed into four equal groups. The 42-day study involved feeding basal diet alone (CON) or diet supplemented with the calf-origin Lactobacillus salivarius strain CPN60 (PRO). The third (CONc) and fourth (PROc) groups of rats also received the same dietary treatments (CON and PRO, respectively) but were subjected to dextran sulfate sodium (DSS)-induced colitis after 32 days of feeding. The results of a digestion trial conducted after 5 days of DSS administration revealed no influence of probiotic on the digestibility of nutrients. However, the reduced digestibility of protein and fat seen in the CONc rats was improved in the PROc group. The concentrations of lactate and acetate, propionate and butyrate, as well as total short-chain fatty acids (SCFA), were increased (P < 0.05) in the caecal and colonic digesta upon probiotic supplementation, together with significantly reduced colonic ammonia levels. Furthermore, there were reductions (P < 0.05) in acetate, butyrate and total SCFA levels in the caecal contents as a result of colitis. Probiotic supplementation increased (P < 0.05) lactobacilli and bifidobacteria counts in the colon, whereas clostridia and coliform counts were reduced (P < 0.05). These were reversed by the probiotic supplementation.

CONCLUSION

Dietary supplementation of L. salivarius CPN60 had a positive effect with respect to improving the overall gut health of healthy rats, as well as that of rats exposed to experimental colitis. © 2020 Society of Chemical Industry.

Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity

Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.

Effects of alternate-day fasting, time-restricted fasting and intermittent energy restriction DSS-induced on colitis and behavioral disorders

Intermittent fasting (IF) has been reported to have beneficial effects on improving gut function via lowering gut inflammation and altering the gut microbiome diversity. In this study, we aimed to investigate the differential effects of three different common IF treatments, alternate day fasting (ADF), time-restricted fasting (TRF), and intermittent energy restriction (IER), on a dextran sodium sulfate (DSS)-induced colitis mouse model. The results indicated that TRF and IER, but not ADF improved the survival rates of the colitis mice. TRF and IER, but not ADF, reversed the colitis pathological development by improving the gut barrier integrity and colon length. Importantly, TRF and IER suppressed the inflammatory responses and oxidative stress in colon tissues. Interestingly, TRF and IER also attenuated colitis-related anxiety-like and obsessive-compulsive disorder behavior and alleviated the neuroinflammation and oxidative stress. TRF and IER also altered the gut microbiota composition, including the decrease of the enrichments of colitis-related microbes such as Shigella and Escherichia Coli, and increase of the enrichments of anti-inflammatory-related microbes. TRF and IER also improved the short chain fatty acid formation in colitis mice. In conclusion, the TRF and IER but not ADF exhibited the protective effects against colitis and related behavioral disorders, which could be partly explained by improving the gut microbiome compositions and preventing gut leak, and consequently suppressing the inflammation and oxidative damages in both colon and brain. The current research indicates that proper IF regimens could be effective strategies for nutritional intervention for the prevention and treatment of colitis.

Fasting-Mimicking Diet Modulates Microbiota and Promotes Intestinal Regeneration to Reduce Inflammatory Bowel Disease Pathology

Dietary interventions are potentially effective therapies for inflammatory bowel diseases (IBDs). We tested the effect of 4-day fasting-mimicking diet (FMD) cycles on a chronic dextran sodium sulfate (DSS)-induced murine model resulting in symptoms and pathology associated with IBD. These FMD cycles reduced intestinal inflammation, increased stem cell number, stimulated protective gut microbiota, and reversed intestinal pathology caused by DSS, whereas water-only fasting increased regenerative and reduced inflammatory markers without reversing pathology. Transplants of Lactobacillus or fecal microbiota from DSS- and FMD-treated mice reversed DSS-induced colon shortening, reduced inflammation, and increased colonic stem cells. In a clinical trial, three FMD cycles reduced markers associated with systemic inflammation. The effect of FMD cycles on microbiota composition, immune cell profile, intestinal stem cell levels and the reversal of pathology associated with IBD in mice, and the anti-inflammatory effects demonstrated in a clinical trial show promise for FMD cycles to ameliorate IBD-associated inflammation in humans.