Beneficial effects of intermittent fasting on steatosis and inflammation of the liver in mice fed a high-fat or a high-fructose diet

Intermittent fasting associated with coconut oil (Cocos nucifera L.) alters gut-liver axis parameters in diet-induced obese rats

OBJECTIVE

The aim of this article is to investigate the effect of intermittent fasting, associated or not with coconut oil intake, on the gut-liver axis of obese rats.

METHODS

A total of 50 rats were divided into five groups: control, obese, obese with intermittent fasting, obese with intermittent fasting plus coconut oil, and obese with caloric restriction. The rats were induced to obesity with a high-sugar diet for 17 wk. The respective interventions were carried out in the last 4 wk.

RESULTS

The groups with intermittent fasting protocols had reduced total cholesterol (on average 54.31%), low-density lipoprotein (on average 53.39%), and triacylglycerols (on average 23.94%) versus the obese group; and the obese with intermittent fasting plus coconut oil group had the highest high-density lipoprotein compared with all groups. The obese with intermittent fasting plus coconut oil and obese with caloric restriction groups had lower metabolic load compared with the other groups. The obese group had high citric and succinic acid concentrations, which affected the hepatic tricarboxylic acid cycle, while all the interventions had reduced concentrations of these acids. No histologic changes were observed in the intestine or liver of the groups.

CONCLUSION

Intermittent fasting, especially when associated with coconut oil, had effects comparable with caloric restriction in modulating the parameters of the gut-liver axis.

The Relationship between Pathogenesis and Possible Treatments for the MASLD-Cirrhosis Spectrum

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a term that entails a broad spectrum of conditions that vary in severity. Its development is influenced by multiple factors such as environment, microbiome, comorbidities, and genetic factors. MASLD is closely related to metabolic syndrome as it is caused by an alteration in the metabolism of fatty acids due to the accumulation of lipids because of an imbalance between its absorption and elimination in the liver. Its progression to fibrosis is due to a constant flow of fatty acids through the mitochondria and the inability of the liver to slow down this metabolic load, which generates oxidative stress and lipid peroxidation, triggering cell death. The development and progression of MASLD are closely related to unhealthy lifestyle habits, and nutritional epigenetic and genetic mechanisms have also been implicated. Currently, lifestyle modification is the first-line treatment for MASLD and nonalcoholic steatohepatitis; weight loss of ≥10% produces resolution of steatohepatitis and fibrosis regression. In many patients, body weight reduction cannot be achieved; therefore, pharmacological treatment should be offered in particular populations.

Intermittent fasting protects β-cell identity and function in a type-2 diabetes model

Type 2 diabetes (T2DM) is caused by the interaction of multiple genes and environmental factors. T2DM is characterized by hyperglycemia, insulin secretion deficiency and insulin resistance. Chronic hyperglycemia induces β-cell dysfunction, loss of β-cell mass/identity and β-cell dedifferentiation. Intermittent fasting (IF) a commonly used dietary regimen for weight-loss, also induces metabolic benefits including reduced blood glucose, improved insulin sensitivity, reduced adiposity, inflammation, oxidative-stress and increased fatty-acid oxidation; however, the mechanisms underlying these effects in pancreatic β-cells remain elusive. KK and KKAy, mouse models of polygenic T2DM spontaneously develop hyperglycemia, glucose intolerance, glucosuria, impaired insulin secretion and insulin resistance. To determine the long-term effects of IF on T2DM, 6-weeks old KK and KKAy mice were subjected to IF for 16 weeks. While KKAy mice fed ad-libitum demonstrated severe hyperglycemia (460 mg/dL) at 6 weeks of age, KK mice showed blood glucose levels of 230 mg/dL, but progressively became severely diabetic by 22-weeks. Strikingly, both KK and KKAy mice subjected to IF showed reduced blood glucose and plasma insulin levels, decreased body weight gain, reduced plasma triglycerides and cholesterol, and improved insulin sensitivity. They also demonstrated enhanced expression of the β-cell transcription factors NKX6.1, MAFA and PDX1, and decreased expression of ALDH1a3 suggesting protection from loss of β-cell identity by IF. IF normalized glucose stimulated insulin secretion in islets from KK and KKAy mice, demonstrating improved β-cell function. In addition, hepatic steatosis, gluconeogenesis and inflammation was decreased particularly in KKAy-IF mice, indicating peripheral benefits of IF. These results have important implications as an optional intervention for preservation of β-cell identity and function in T2DM.

Ramadan fasting model exerts hepatoprotective, anti-obesity, and anti-hyperlipidemic effects in an experimentally-induced nonalcoholic fatty liver in rats

BACKGROUND

The epidemic of nonalcoholic fatty liver disease (NAFLD) and its metabolic effects present a serious public health concern. We hypothesized that the Ramadan fasting model (RFM), which involves fasting from dawn to dusk for a month, could provide potential therapeutic benefits and mitigate NAFLD. Accordingly, we aimed to validate this hypothesis using obese male rats.

METHODS

Rats were split into two groups (n = 24 per group), and they were given either a standard (S) or high-fat diet (HFD) for 12 weeks. During the last four weeks of the study period, both S- and HFD-fed rats were subdivided into eight groups to assess the effect of RFM with/without training (T) or glucose administration (G) on the lipid profile, liver enzymes, and liver structure (n = 6/group).

RESULTS

The HFD+RFM group exhibited a significantly lower final body weight than that in the HFDC group. Serum cholesterol, low-density lipoprotein, and triglyceride levels were significantly lower in the HFD+RFM, HFD+RFM+T, and HFD+RFM+G groups than those in the HFDC group. Compared with the HFDC group, all groups had improved serum high-density lipoprotein levels. Furthermore, HFD groups subjected to RFM had reduced serum levels of aspartate transaminase and alanine transaminase compared with those of the HFD-fed group. Moreover, the liver histology improved in rats subjected to RFM compared with that of HFD-fed rats, which exhibited macro- and micro-fat droplet accumulation.

CONCLUSION

RFM can induce positive metabolic changes and improve alterations associated with NAFLD, including weight gain, lipid profile, liver enzymes, and hepatic steatosis.

Effects of alternate-day fasting and time-restricted feeding in obese middle-aged female rats

OBJECTIVES

Obesity is a multifactorial condition associated with metabolic alterations that can be aggravated during female aging. Calorie restriction via intermittent fasting (IF) diets may reduce body weight and therefore have the potential to decrease obesity and associated comorbidities, such as insulin resistance. This study investigated the effects of two IF protocols, alternate-day fasting (ADF) and time-restricted feeding (TRF) in middle-aged obese female rats.

METHODS

Wistar rats (age 15 mo) were fed with standard chow or high-fat diet for 8 wk and then separated into the following groups (n = 5-8 each) for another 8 wk: control (received standard chow), obese (received high-fat diet), obese + ADF (24-h fasting protocol), and obese + TRF (14 h daily).

RESULTS

At the end of the study, both IF protocols were able to reduce body weight and body mass index compared with the obese group. However, no changes were observed in adiposity and glucose homeostasis. We also found an increase in total leukocytes, lymphocytes, and monocytes in the TRF group and a higher number of platelets in the ADF group. Blood lipid profiles, including triglycerides and high-density lipoprotein, as well as liver stress responses, such as heat shock protein 70 and malondialdehyde, were not changed by IF.

CONCLUSIONS

Although ADF and TRF protocols resulted in a reduction of body weight and body mass index, these dietary interventions did not promote health benefits, such as reducing blood lipid profile, adiposity, and insulin resistance. In addition, ADF and TRF increased inflammatory biomarkers, which may increase the risk of obesity-associated comorbidities.

Mitigation of aircraft noise-induced vascular dysfunction and oxidative stress by exercise, fasting, and pharmacological α1AMPK activation: molecular proof of a protective key role of endothelial α1AMPK against environmental noise exposure

AIMS

Environmental stressors such as traffic noise represent a global threat, accounting for 1.6 million healthy life years lost annually in Western Europe. Therefore, the noise-associated health side effects must be effectively prevented or mitigated. Non-pharmacological interventions such as physical activity or a balanced healthy diet are effective due to the activation of the adenosine monophosphate-activated protein kinase (α1AMPK). Here, we investigated for the first time in a murine model of aircraft noise-induced vascular dysfunction the potential protective role of α1AMPK activated via exercise, intermittent fasting, and pharmacological treatment.

METHODS AND RESULTS

Wild-type (B6.Cg-Tg(Cdh5-cre)7Mlia/J) mice were exposed to aircraft noise [maximum sound pressure level of 85 dB(A), average sound pressure level of 72 dB(A)] for the last 4 days. The α1AMPK was stimulated by different protocols, including 5-aminoimidazole-4-carboxamide riboside application, voluntary exercise, and intermittent fasting. Four days of aircraft noise exposure produced significant endothelial dysfunction in wild-type mice aorta, mesenteric arteries, and retinal arterioles. This was associated with increased vascular oxidative stress and asymmetric dimethylarginine formation. The α1AMPK activation with all three approaches prevented endothelial dysfunction and vascular oxidative stress development, which was supported by RNA sequencing data. Endothelium-specific α1AMPK knockout markedly aggravated noise-induced vascular damage and caused a loss of mitigation effects by exercise or intermittent fasting.

CONCLUSION

Our results demonstrate that endothelial-specific α1AMPK activation by pharmacological stimulation, exercise, and intermittent fasting effectively mitigates noise-induced cardiovascular damage. Future population-based studies need to clinically prove the concept of exercise/fasting-mediated mitigation of transportation noise-associated disease.

Timing of energy intake and the therapeutic potential of intermittent fasting and time-restricted eating in NAFLD

Non-alcoholic fatty liver disease (NAFLD) represents a major public health concern and is associated with a substantial global burden of liver-related and cardiovascular-related morbidity and mortality. High total energy intake coupled with unhealthy consumption of ultra-processed foods and saturated fats have long been regarded as major dietary drivers of NAFLD. However, there is an accumulating body of evidence demonstrating that the timing of energy intake across a the day is also an important determinant of individual risk for NAFLD and associated metabolic conditions. This review summarises the available observational and epidemiological data describing associations between eating patterns and metabolic disease, including the negative effects of irregular meal patterns, skipping breakfast and night-time eating on liver health. We suggest that that these harmful behaviours deserve greater consideration in the risk stratification and management of patients with NAFLD particularly in a 24-hour society with continuous availability of food and with up to 20% of the population now engaged in shiftwork with mistimed eating patterns. We also draw on studies reporting the liver-specific impact of Ramadan, which represents a unique real-world opportunity to explore the physiological impact of fasting. By highlighting data from preclinical and pilot human studies, we present a further biological rationale for manipulating timing of energy intake to improve metabolic health and discuss how this may be mediated through restoration of natural circadian rhythms. Lastly, we comprehensively review the landscape of human trials of intermittent fasting and time-restricted eating in metabolic disease and offer a look to the future about how these dietary strategies may benefit patients with NAFLD and non-alcoholic steatohepatitis.

Effects of time-restricted feeding (16/8) combined with a low-sugar diet on the management of non-alcoholic fatty liver disease: A randomized controlled trial

OBJECTIVES

Emerging studies have employed time-restricted feeding (TRF) and a low-sugar diet alone in the management of non-alcoholic fatty liver disease (NAFLD), but their combination has not been tested. The aim of this study was to investigate the effects of TRF combined with a low-sugar diet on NAFLD parameters, cardiometabolic and inflammatory biomarkers, and body composition in patients with NAFLD.

METHODS

A 12-wk randomized controlled trial was performed to compare the effects of TRF (16 h fasting/8 h feeding daily [16/8]) plus a low-sugar diet versus a control diet based on traditional meal distribution in patients with NAFLD. Changes in body composition, anthropometric indices, and liver and cardiometabolic markers were investigated.

RESULTS

TRF 16/8 with a low-sugar diet reduced body fat (26.7 ± 5.4 to 24.2 ± 4.9 kg), body weight (83.8 ± 12.7 to 80.5 ± 12.1 kg), waist circumference (104.59 ± 10.47 to 101.91 ± 7.42 cm), and body mass index (29.1 ± 2.6 to 28 ± 2.7 kg/m²), as well as circulating levels of fasting blood glucose and liver (alanine aminotransferase, 34 ± 13.9 to 21.2 ± 5.4 U/L; aspartate aminotransferase, 26.3 ± 6.2 to 20.50 ± 4 U/L; γ-glutamyl transpeptidase, 33 ± 15 to 23.2 ± 11.1 U/L; fibrosis score, 6.3 ± 1 to 5.2 ± 1.2 kPa; and controlled attenuation parameter, 322.9 ± 34.9 to 270.9 ± 36.2 dB/m), lipids (triacylglycerols, 201.5 ± 35.3 to 133.3 ± 48.7 mg/dL; total cholesterol, 190 ± 36.6 to 157.8 ± 33.6 mg/dL; and low-density lipoprotein cholesterol, 104.6 ± 27.3 to 84 ± 26.3 mg/dL), and inflammatory markers (high-sensitivity C-reactive protein, 3.1 ± 1.1 to 2 ± 0.9 mg/L; and cytokeratin-18, 1.35 ± 0.03 to 1.16 ± 0.03 ng/mL). These results were statistically significant (P < 0.05) compared with the control group.

CONCLUSIONS

TRF plus a low-sugar diet can reduce adiposity and improve liver, lipid, and inflammatory markers in patients with NAFLD.

Intermittent fasting attenuates lipopolysaccharide-induced acute lung injury in mice by modulating macrophage polarization

Acute lung injury (ALI) is a spectrum of acute and life-threatening pulmonary inflammatory conditions. Treatment of ALI remains a clinical challenge. Recently, intermittent fasting (IF) has been shown to improve health and alleviate many diseases. In this study, we tested whether IF attenuated ALI and investigated the mechanism underlying this process. In vivo, the effects of IF on ALI were evaluated in a lipopolysaccharide (LPS)-induced murine ALI model. We found that two times of 24-h fasting in a week before ALI efficiently ameliorated LPS-induced lung injury in mice, characterized by alleviated lung lesions, wet-to-dry weight ratio, myeloperoxidase activity, malondialdehyde content, and lower levels of tumor necrosis factor-α, interleukin-6, and interleukin-1β. In vitro, functional assays were conducted to assess IF on the inflammatory response and macrophage polarization of bone marrow-derived macrophages (BMDMs) treated with LPS or IL-4. And PPARγ antagonist GW9662 and AMPK siRNA were used to test the role of PPARγ and AMPK in the IF-mediated improvement of ALI. The results showed that IF (serum deprivation) suppressed macrophage M1 activation and promoted M2 activation in LPS-treated BMDMs. While, IF also augmented macrophage M2 polarization in IL-4-treated BMDMs. Further mechanistic studies showed that the promotive effect of IF on M2 polarization was related to the activation of the PPARγ and AMPK pathways. In conclusion, this study suggests that IF enhances M2 polarization by activating the AMPK and PPARγ pathways, thus facilitating anti-inflammatory response and ameliorating ALI.

Intermittent Fasting—A Healthy Dietary Pattern for Diabetic Nephropathy

Diabetic nephropathy (DN), a metabolic disease, is characterized by severe systemic metabolic disorders. A unique dietary pattern, such as intermittent fasting (IF) has shown promising protective effects on various metabolic diseases, such as diabetes and cardiovascular and nervous system diseases. However, its role in regulating kidney disease, especially in DN, is still being investigated. Here, we summarize the current research progress, highlighting the relationship between IF and the risk factors for the progression of DN, and discuss the potential mechanisms by which IF improves renal injury in DN. Finally, we propose IF as a potential strategy to prevent and delay DN progression. Abbreviation: DN: Diabetic nephropathy; IF: Intermittent fasting; CPT1A: Carnitine palmitoyltransferase 1A; L-FABP: Liver-type fatty acid-binding protein; STZ: Streptozotocin; LDL: Low-density lipoproteins; HIIT: High-intensity interval training; CKD: Chronic kidney disease; ACEI: Angiotensin-converting enzyme inhibitors; ARB: Angiotensin receptor blockers; MDA: Malondialdehyde; mtDNA: Mitochondrial DNA; UCP3: Uncoupling protein-3; MAM: Mitochondria-associated endoplasmic reticulum membrane; PBMCs: Peripheral blood mononuclear cells; ERK1/2: Extracellular signal-regulated kinase 1/2; DRP1: Dynamin-related protein 1; β-HB: β-Hydroxybutyrate; AcAc: Acetoacetate; GEO: Gene Expression Omnibus; NCBI: National Center for Biotechnology Information; mTORC1: Mechanistic target of rapamycin complex 1; HMGCS2: 3-Hydroxy-3-methylglutaryl-CoA synthase 2; GSK3β: Glycogen synthase kinase 3β; AKI: Acute kidney injury; CMA: Chaperone-mediated autophagy; FGF21: Fibroblast growth factor 21.

Dietary Risk Factors and Eating Behaviors in Peripheral Arterial Disease (PAD)

Dietary risk factors play a fundamental role in the prevention and progression of atherosclerosis and PAD (Peripheral Arterial Disease). The impact of nutrition, however, defined as the process of taking in food and using it for growth, metabolism and repair, remains undefined with regard to PAD. This article describes the interplay between nutrition and the development/progression of PAD. We reviewed 688 articles, including key articles, narrative and systematic reviews, meta-analyses and clinical studies. We analyzed the interaction between nutrition and PAD predictors, and subsequently created four descriptive tables to summarize the relationship between PAD, dietary risk factors and outcomes. We comprehensively reviewed the role of well-studied diets (Mediterranean, vegetarian/vegan, low-carbohydrate ketogenic and intermittent fasting diet) and prevalent eating behaviors (emotional and binge eating, night eating and sleeping disorders, anorexia, bulimia, skipping meals, home cooking and fast/ultra-processed food consumption) on the traditional risk factors of PAD. Moreover, we analyzed the interplay between PAD and nutritional status, nutrients, dietary patterns and eating habits. Dietary patterns and eating disorders affect the development and progression of PAD, as well as its disabling complications including major adverse cardiovascular events (MACE) and major adverse limb events (MALE). Nutrition and dietary risk factor modification are important targets to reduce the risk of PAD as well as the subsequent development of MACE and MALE.

ANGPTL8 accelerates liver fibrosis mediated by HFD-induced inflammatory activity via LILRB2/ERK signaling pathways

INTRODUCTION

High calorie intake is known to induce nonalcoholic fatty liver disease (NAFLD) by promoting chronic inflammation. However, the mechanisms are poorly understood.

OBJECTIVES

This study examined the roles of ANGPTL8 in the regulation of NAFLD-associated liver fibrosis progression induced by high fat diet (HFD)-mediated inflammation.

METHODS

The ANGPTL8 concentration was measured in serum samples from liver cancer and liver cirrhosis patients. ANGPTL8 knockout mice were used to induce disease models (HFD, HFHC and CCL4) followed by pathological staining, western blot and immunohistochemistry. Hydrodynamic injection of an adeno-associated virus 8 (AAV8) was used to establish a model for restoring ANGPTL8 expression specifically in ANGPTL8 KO mice livers. RNA-sequencing, protein array, Co-IP, etc. were used to study ANGPTL8's mechanisms in regulating liver fibrosis progression, and drug screening was used to identify an effective inhibitor of ANGPTL8 expression.

RESULTS

ANGPTL8 level is associated with liver fibrogenesis in both cirrhosis and hepatocellular carcinoma patients. Mouse studies demonstrated that ANGPTL8 deficiency suppresses HFD-stimulated inflammatory activity, hepatic steatosis and liver fibrosis. The AAV-mediated restoration of liver ANGPTL8 expression indicated that liver-derived ANGPTL8 accelerates HFD-induced liver fibrosis. Liver-derived ANGPTL8, as a proinflammatory factor, activates HSCs (hepatic stellate cells) by interacting with the LILRB2 receptor to induce ERK signaling and increase the expression of genes that promote liver fibrosis. The FDA-approved drug metformin, an ANGPTL8 inhibitor, inhibited HFD-induced liver fibrosis in vivo.

CONCLUSIONS

Our data support that ANGPTL8 is a proinflammatory factor that accelerates NAFLD-associated liver fibrosis induced by HFD. The serum ANGPTL8 level may be a potential and specific diagnostic marker for liver fibrosis, and targeting ANGPTL8 holds great promise for developing innovative therapies to treat NAFLD-associated liver fibrosis.

SIRT1 mediates nutritional regulation of SREBP-1c-driven hepatic PNPLA3 transcription via modulation of H3k9 acetylation

Background

Patatin-like phospholipase domain containing 3 (PNPLA3) is the main nonalcoholic fatty liver disease (NAFLD) susceptibility. Its expression is regulated tightly by nutritional and energy status, but the mechanism of epigenetic regulation of PNPLA3 gene by nutritional dietary factors has not been reported. Here, we investigated the effect and mechanism of Sirtuin 1 (SIRT1) regulated H3K9 deacetylation on PNPLA3 transcriptional expression in vivo and in vitro.

Methods

Mouse models of fasting/re-feeding transition and nonalcoholic fatty liver induced by high Sucrose diet were constructed; and HepG2 cells were treated with serum- and glucose-free medium or exposed to high glucose and high insulin, to generate fasting and high-glucose-induced lipid deposition cell states. Enrichment levels of histone H3K9 acetylation and sterol responsive element binding protein-1c (SREBP-1c) at the PNPLA3 promoter were observed by ChIP-qPCR. PNPLA3 gene expression was detected by real-time PCR; SIRT1 protein expression was detected by western blot. And lipid deposition was detected by Oil Red O.

Results

H3K9ac levels at SRE regions of PNPLA3 promoter were found to be decreased in mice during fasting and increase during refeeding, and increased in mice with NAFLD induced by high-sucrose diet. The change pattern of PNPLA3 promoter H3K9Ac physiologically (fasting/refeeding) and pathologically was consistent with that of PNPLA3 gene expression, but opposite to that of SIRT1 protein expression. In HepG2 cells, overexpression of SIRT1 inhibited high-glucose induced hyper-acetylation of H3K9 at PNPLA3 promoter, and silent expression of SIRT1 suppressed fasting-induced hypo-acetylation of H3K9. Overexpression of SIRT1 prevented basal and SREBP-1c-driven PNPLA3 gene expression and also prevented the endogenous binding of SREBP-1c to PNPLA3.

Conclusions

We first preliminarily revealed SIRT1 may regulate PNPLA3 gene expression by affecting SREBP-1-driven transcription via acetylation modification of H3K9.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41021-022-00246-1.

Benefits, mechanisms, and risks of intermittent fasting in metabolic syndrome and type 2 diabetes

One of the emergent nutritional strategies for improving multiple features of cardiometabolic diseases is the practice of intermittent fasting (IF), which consists of alternating periods of eating and fasting. IF can reduce circulating glucose and insulin levels, fat mass, and the risk of developing age-related pathologies. IF appears to upregulate evolution-conserved adaptive cellular responses, such as stress-response pathways, autophagy, and mitochondrial function. IF was also observed to modulate the circadian rhythms of hormones like insulin or leptin, among others, which levels change in conditions of food abundance and deficit. However, some contradictory results regarding the duration of the interventions and the anterior metabolic status of the participants suggest that more and longer studies are needed in order to draw conclusions. This review summarizes the current knowledge regarding the role of IF in the modulation of mechanisms involved in type 2 diabetes, as well as the risks.

Intermittent Fasting before Laparotomy: Effects on Glucose Control and Histopathologic Findings in Diabetic Rats

(1) Background: Intermittent fasting is a nutrition practice in which individuals fast for several hours in a day, mainly with feeding time during the daylight hours. They seek to improve metabolic performance and cellular resistance to stress. In this study, we tested the fasting protocol to investigate the glycemic effect in a laparotomy perioperative period in diabetic rats and histopathologic findings. (2) Methods: The animals were diabetic-induced with alloxan. Two groups were set according to the feeding protocol: free food and intermittent fasting, whose rats could only eat 8 h in the daylight. Both groups were anesthetized, and a laparotomy was performed. We evaluated the glucose levels during the perioperative period, and we accessed organ histology seeking damage of kidney, bowel and liver after surgical trauma, and we evaluated the wound healing process. (3) Results: Glycemic levels were improved in the intermittent fasting group, especially in the post-operative period after laparotomy. Comparing both groups' tubular damage showed interdependency with mice with worse glycemic level (Z = 2.3; p = 0.0215) and wound-healing parameters showed interdependency with rats with better glycemic status for neovascularization (Z = 2.2; p = 0.0273) and the presence of sebaceous and sweat gland in the healing process (Z = 2.30; p = 0.0215). (4) Conclusions: Intermittent fasting before surgery can be a tool to improve glycemic levels in diabetic rats, with improvement especially in the post-operative period.

Pancreatic islet cells disarray, apoptosis, and proliferation in obese mice. The role of Semaglutide treatment

There are significant injuries of pancreatic islets due to obesity and insulin resistance. Therefore, GLP-1 receptor agonists like Semaglutide might benefit the islet structural remodeling and its endocrine function in diet-induced obese mice. One-month-old male C57BL/6 mice were allotted into two dietary groups (n = 60/group) and fed for 16 weeks a control diet (C) or a high‒fat diet (HF). Then, for an additional four weeks, the main groups were resampled to include treatment (Semaglutide, S, 40 μg/kg), or paired feed with the treated group (PF), totaling six groups (n = 20/group): C, CS, CPF, HF, HFS, HFPF. Biochemistry, stereology, immunohistochemistry/immunofluorescence, confocal microscopy, and RT-qPCR were used in the study. The mouse model reproduced metabolism and bodily changes due to diet-induced obesity. Pancreatic islet hypertrophy was observed with alpha- and beta-cell remodeling, cell disarray, and apoptosis. Semaglutide increased islet cell proliferation and recovered islet size and alpha- and beta-cell masses. The changes include recovery of glucose and hormone levels, reduction of pro-inflammatory markers, improvement of pancreatic duodenal homeobox 1 (PDX-1), glucose transporter 2 (GLUT-2), v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MAF-A), and peroxisome proliferator-activated receptors (PPAR) -gamma. In conclusion, damage to the pancreatic islet caused by insulin resistance and the attempt to adapt the islet of obese mice involved different pathways, especially the pro-inflammatory pathway, PDX1, and PPAR-alpha and gamma. Semaglutide showed beneficial effects on these pathways, reducing the lesion on the islet. However, the weight loss influence of Semaglutide was of little relevance in the pancreatic islet.

Anemarrhena saponins attenuate insulin resistance in rats with high-fat diet-induced obesity via the IRS-1/PI3K/AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Anemarrhena asphodeloides is the dry rhizome of Anemarrhena asphodeloides Bge. Anemarrhena Saponins isolated from Anemarrhena asphodeloides are one of the pharmacologically active components of this plant and have blood lipid reduction and blood glucose reduction properties. These facts suggest that these saponins might be helpful in the treatment of insulin resistance.

AIM OF THE STUDY

To determine the therapeutic effect of anemarrhena saponins on insulin resistance and the probable underlying mechanism.

MATERIALS AND METHODS

Insulin-resistant rats were used as the experimental subject, to observe the therapeutic effect of anemarrhena saponins. The blood glucose and blood lipid parameters were determined using the relevant kits. We used hematoxylin and eosin (H&E) staining to observe the protective effect of anemarrhena saponins on the livers of insulin-resistant rats and reverser transcripition polymerase chain reaction (RT-PCR) to analyze the mRNA expressions patterns of genes related to glucose metabolism and inflammatory factors. The toxicity of anemarrhena saponins to HepG2 cells was calculated using the MTT assay. Further, we conducted in vivo and in vitro experiments, and Western-blot analysis to study the effects of anemarrhena saponins on the IRS-1/PI3K/AKT pathway.

RESULTS

Anemarrhena saponins were found to improve dyslipidemia, reduce obesity and inflammation, and alleviate liver injury in insulin-resistant rats. Anemarrhena saponins also reduced the mRNA expression of gluconeogenesis-related genes sunch as G6pase, PEPCK, and GSK3β in the liver. Moreover, anemarrhena saponins up-regulated the phosphorylation levels of IRS-1, PI3K and AKT, promoted insulin signal transduction, and reduced liver injury induced by insulin resistance.

CONCLUSIONS

These findings suggest that anemarrhena saponins could promote insulin signal transduction through the IRS-1/PI3K/AKT pathway, thereby reducing the damage caused by insulin resistance.

Obese mice weight loss role on nonalcoholic fatty liver disease and endoplasmic reticulum stress treated by a GLP-1 receptor agonist

BACKGROUND/OBJECTIVES

The weight loss following Semaglutide treatment, a GLP-1 receptor agonist, might be responsible for some effects observed on the nonalcoholic fatty liver disease of obese mice.

SUBJECTS/METHODS

Two groups of C57BL/6 male mice (n = 30/group) were fed the diets Control (C) or high-fat (HF) for 16 weeks. Then, separated into six new groups for an additional four weeks (n = 10/group) and treated with Semaglutide (S, 40 µg/kg) or paired feeding (PF) with S groups (C; C-S; C-PF; HF; HF-S; HF-PF).

RESULTS

Semaglutide reduced energy consumption leading to weight loss. Simultaneously it improved glucose intolerance, glycated hemoglobin, insulin resistance/sensitivity, plasma lipids, and gastric inhibitory polypeptide. Semaglutide and paired feeding mitigated liver steatosis and adipose differentiation-related protein (Plin2) expression. Semaglutide also improved hormones and adipokines, reduced lipogenesis and inflammation, and increased beta-oxidation. Semaglutide lessened liver glucose uptake and endoplasmic reticulum (ER) stress. Among the 14 genes analyzed, 13 were modified by Semaglutide (93 %, six genes were changed exclusively by Semaglutide, and seven other genes were affected by the combination of Semaglutide and paired feeding). In seven genes, the paired diet showed no effect (50% of the genes tested). No marker was affected exclusively by paired feeding.

CONCLUSIONS

Semaglutide and the consequent weight loss reduced obese mice liver inflammation, insulin resistance, and ER stress. However, weight loss alone did show few or no action on some significant study findings, like liver steatosis, leptin, insulin, resistin, and amylin. Furthermore, hepatic inflammation mediated by MCP-1 and partially by TNF-alpha and IL6 were also not reduced by weight loss. Furthermore, weight loss alone did not lessen hepatic lipogenesis as determined by the findings of SREBP-1c, CHREBP, PPAR-alpha, and SIRT1. Semaglutide was implicated in improving glucose uptake and lessening ER stress by reducing GADD45, independent of weight loss.

Consequences of Paternal Nutrition on Offspring Health and Disease

It is well established that the maternal diet during the periconceptional period affects the progeny’s health. A growing body of evidence suggests that the paternal diet also influences disease onset in offspring. For many years, sperm was considered only to contribute half of the progeny’s genome. It now appears that it also plays a crucial role in health and disease in offspring’s adult life. The nutritional status and environmental exposure of fathers during their childhood and/or the periconceptional period have significant transgenerational consequences. This review aims to describe the effects of various human and rodent paternal feeding patterns on progeny’s metabolism and health, including fasting or intermittent fasting, low-protein and folic acid deficient food, and overnutrition in high-fat and high-sugar diets. The impact on pregnancy outcome, metabolic pathways, and chronic disease onset will be described. The biological and epigenetic mechanisms underlying the transmission from fathers to their progeny will be discussed. All these data provide evidence of the impact of paternal nutrition on progeny health which could lead to preventive diet recommendations for future fathers.

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.

Effects of intermittent fasting on liver physiology and metabolism in mice

A broad spectrum of health benefits from intermittent fasting have been reported in studies on animal models and human subjects. However, the underlying mechanisms of these beneficial effects remain largely elusive. The present study aimed to explore the effects and potential mode of action of intermittent fasting in mouse models with a focus on the liver. C57BL/6 mice were subjected to intermittent fasting or ad libitum feeding as controls. It was determined that 12 h of daily intermittent fasting for 30 days significantly reduced the cumulative food intake compared with that in mice with ad libitum feeding. Fasting resulted in a significantly reduced liver mass but only had a minimal effect on bodyweight. The effects on the liver by 30 days of fasting were not reversed by subsequent ad libitum refeeding for 30 days. Among the measured blood biochemical parameters, the levels of blood glucose were decreased, while the levels of alkaline phosphatase were increased in fasting mice. Of note, targeted metabolic profiling revealed global elevation of metabolites in the livers of fasting mice. These metabolic molecules included adenosine triphosphate, nicotinamide adenine dinucleotide phosphate (NADP), reduced NADP and succinate, which are essentially involved in the citric acid cycle and oxidative phosphorylation. Thus, it was concluded that daily 12 h of intermittent fasting for one month significantly reduced the liver weight of mice, which is associated with enhanced liver metabolism.

Reversion to regular diet with alternate day fasting can cure grade-I non-alcoholic fatty liver disease (NAFLD) in high-fructose-intake-associated metabolic syndrome

Background

Non-alcoholic fatty liver disease (NAFLD) is an emerging global health problem that accompanied the obesity epidemic and is considered as the hepatic component of metabolic syndrome (MetS). Modification of lifestyle of MetS patients remains the focus to reverse and prevent progression of hepatic steatosis to NAFLD and its worsening to severe forms. The present study investigates the possible curability of metabolic syndrome -associated grade-1 NAFLD merely by alternate day fasting with or without reversion to regular diet in adult male rats. The present study was performed on 66 local strain male rats aged (6–10 m.) distributed randomly into C group (n = 12), on regular rat diet; and M group (n = 54) on high fructose- intake. On the 8th week, then rats were subjected to measurement of BW, BMI, WC, FBG, IPGTT, HDL-C, TGs, and liver histopathology, to include MetS rats randomly into four experimental groups for 4 weeks as follows: MS (n = 14); MSRD (n = 12); MSF (n = 13); and MSRDF (n = 12). On the 12th week, all rats were subjected to measurements of BW, BMI, WC, LW, LW/BW, VFW, VFW/BW, FBG, IPGTT, Ins., HOMA-IR, HbA1C, TGs, TC, LDL-C, HDL-C, CRP, Alb., bilirubin, ALT, L-MDA, and liver histopathology.

Results

On the 8th week, M group developed MerS and grade-I NAFLD with score-4 hepatosteatosis (69%). On the 12th week, MS group had grade-1 NAFLD with score-4 hepatosteatosis (82%) with significantly increased Ins., HOMA-IR, HDL-C, LW, LW/BW, L-MDA, ALT, CRP, and significantly decreased Alb. than C rats. Both MSRD and MSF groups had grade-1 NAFLD with score-3 hepatosteatosis (42%) with significantly decreased Ins., HOMA-IR, TC, LDL-C, LW, LW/BW, L-MDA, ALT, CRP, and significantly increased HDL-C and Alb. than MS group. MSRDF rats showed cure of grade-1 NAFLD and significantly decreased LW than other groups and normalized HOMA-IR, HbA1C TC, LDL-C, ALT, and CRP.

Conclusion

One month of alternate-day fasting and regular rat diet could cure grade-I NAFLD associated with Mets due to high fructose intake possibly by attenuating metabolic disorders. These two interventions might be recommended in the management of MetS patients with grade 1-NAFLD disease.

A rise in Proteobacteria is an indicator of gut-liver axis-mediated nonalcoholic fatty liver disease in high-fructose-fed adult mice

Current evidence suggests that high fructose intake results in gut dysbiosis, leading to endotoxemia and NAFLD onset. Thus, the hypothesis of the study was that an enhanced Proteobacteria proportion in the cecal microbiota could be the most prominent trigger of NAFLD through enhanced endotoxin (LPS) in adult high-fructose-fed C57BL/6 mice. Male C57BL/6 mice received a control diet (n = 10, C: 76% of energy as carbohydrates, 0% as fructose) or high-fructose diet (n = 10, HFRU: 76% of energy as carbohydrate, 50% as fructose) for 12 weeks. Outcomes included biochemical analyses, 16S rDNA PCR amplification, hepatic stereology, and RT-qPCR. The groups showed similar body masses during the whole experiment. However, the HFRU group showed greater water intake and blood pressure than the C group. The HFRU group showed a significantly lower amount of Bacteroidetes and a predominant rise in Proteobacteria, implying increased LPS. The HFRU group also showed enhanced de novo lipogenesis (Chrebp expression), while beta-oxidation was decreased (Ppar-alpha expression). These results agree with the deposition of fat droplets within hepatocytes and the enhanced hepatic triacylglycerol concentrations, as observed in the photomicrographs, where the HFRU group had a higher volume density of steatosis than the C group. Thus, we confirmed that a rise in the Proteobacteria phylum proportion was the most prominent alteration in gut-liver axis-induced hepatic steatosis in HFRU-fed C57BL/6 mice. Gut dysbiosis and fatty liver were observed even in the absence of overweight in this dietary adult mouse model.

Is there any role of intermittent fasting in the prevention and improving clinical outcomes of COVID-19?: intersection between inflammation, mTOR pathway, autophagy and calorie restriction

The coronavirus disease 2019 (COVID-19) pandemic is provoking a global public health crisis. Even though the academic world is intensively pursuing new therapies, there is still no “game changer” in the management of COVID 19. The Mammalian Target of Rapamycin (mTOR) is an ancient signaling system that has been proposed as a molecular tool used by coronaviruses and other RNA and DNA viruses in order to replicate and persist in the host cell. In recent years, Intermittent Fasting (IF), a practice consisting on a strict calorie restriction during a prolonged period of time during the day, has gained popularity due to its potential benefits in multiple health systems and in regulating inflammation. IF inhibits the mTOR pathway which is similar to the effects of Rapamycin in some animal models. mTOR inhibition and promotion of autophagy could potentially be the link between the possible direct benefits of IF in COVID-19 due to the interruption of the viral cycle (protein synthesis). Besides, IF has shown to be a strong anti-inflammatory in multiple prior studies, and may play a role in attenuating COVID -19 severity. This review hypothesizes the possible intersection between viral, immunological, and metabolic pathways related to mTOR and the potential mechanisms through which IF may improve clinical outcomes. Future prospective randomized controlled clinical trials to evaluate intermittent fasting (IF) regimens in order to prevent and treat moderate to severe forms of COVID-19 in humans are needed.

Restructuring the Gut Microbiota by Intermittent Fasting Lowers Blood Pressure

[Figure: see text].

The effect of calorie intake, fasting, and dietary composition on metabolic health and gut microbiota in mice

Background

Calorie restriction (CR) and intermittent fasting (IF) can promote metabolic health through a process that is partially mediated by gut microbiota modulation. To compare the effects of CR and IF with different dietary structures on metabolic health and the gut microbiota, we performed an experiment in which mice were subjected to a CR or IF regimen and an additional IF control (IF^Ctrl) group whose total energy intake was not different from that of the CR group was included. Each regimen was included for normal chow and high-fat diet.

Results

We showed that in normal-chow mice, the IF^Ctrl regimen had similar positive effects on glucose and lipid metabolism as the CR regimen, but the IF regimen showed almost no influence compared to the outcomes observed in the ad libitum group. IF also resulted in improvements, but the effects were less marked than those associate with CR and IF^Ctrl when the mice were fed a high-fat diet. Moreover, CR created a stable and unique gut microbial community, while the gut microbiota shaped by IF exhibited dynamic changes in fasting-refeeding cycles. At the end of each cycle, the gut microbiota of the IF^Ctrl mice was similar to that of the CR mice, and the gut microbiota of the IF mice was similar to that of the ad libitum group. When the abundance of Lactobacillus murinus OTU2 was high, the corresponding metabolic phenotype was improved regardless of eating pattern and dietary structure, which might be one of the key bacterial groups in the gut microbiota that is positively correlated with metabolic amelioration.

Conclusion

There are interactions among the amount of food intake, the diet structure, and the fasting time on metabolic health. The structure and composition of gut microbiota modified by dietary regimens might contribute to the beneficial effects on the host metabolism.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-021-00987-5.

Fructose Consumption Affects Glucocorticoid Signaling in the Liver of Young Female Rats

The effects of early-life fructose consumption on hepatic signaling pathways and their relation to the development of metabolic disorders in later life are not fully understood. To investigate whether fructose overconsumption at a young age induces alterations in glucocorticoid signaling that might contribute to development of metabolic disturbances, we analysed glucocorticoid receptor hormone-binding parameters and expression of its target genes involved in gluconeogenesis (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) and lipid metabolism (lipin-1), as well as redox and inflammatory status in the liver of female rats subjected to a fructose-rich diet immediately after weaning. The fructose diet increased hepatic corticosterone concentration, 11β-hydroxysteroid dehydrogenase type 1 level, glucocorticoid receptor protein level and hormone-binding activity, as well as lipin-1 level. The expression of glucose-6-phosphatase was reduced in fructose-fed rats, while phosphoenolpyruvate carboxykinase remained unaltered. The fructose-rich diet increased the level of fructose transporter GLUT2, while the expression of fructolytic enzymes fructokinase and aldolase B remained unaltered. The diet also affected pro-inflammatory pathways, but had no effect on the antioxidant defence system. In conclusion, a fructose-rich diet applied immediately after weaning promoted lipogenesis and enhanced hepatic glucocorticoid signaling, possibly to protect against inflammatory damage, but without an effect on gluconeogenesis and antioxidant enzymes. Yet, prolonged treatment might ultimately lead to more pronounced metabolic disturbances.

Understanding Dietary Intervention-Mediated Epigenetic Modifications in Metabolic Diseases

The global prevalence of metabolic disorders, such as obesity, diabetes and fatty liver disease, is dramatically increasing. Both genetic and environmental factors are well-known contributors to the development of these diseases and therefore, the study of epigenetics can provide additional mechanistic insight. Dietary interventions, including caloric restriction, intermittent fasting or time-restricted feeding, have shown promising improvements in patients' overall metabolic profiles (i.e., reduced body weight, improved glucose homeostasis), and an increasing number of studies have associated these beneficial effects with epigenetic alterations. In this article, we review epigenetic changes involved in both metabolic diseases and dietary interventions in primary metabolic tissues (i.e., adipose, liver, and pancreas) in hopes of elucidating potential biomarkers and therapeutic targets for disease prevention and treatment.

Browning of the subcutaneous adipocytes in diet-induced obese mouse submitted to intermittent fasting

PURPOSE

We studied subcutaneous white adipose tissue (sWAT) of obese mice submitted to intermittent fasting (IF).

METHODS

Twelve-week-old C57BL/6 male mice received the diets Control (C) or high-fat (HF) for eight weeks (n = 20/each). Then, part of each group performed IF (24 h feeding/24 h fasting) for four weeks: C, C-IF, HF, and HF-IF (n = 10/each).

RESULTS

Food intake did not show a difference in feeding and fasting days, but HF groups had a high energy intake. IF led to multilocular adipocytes in sWAT (browning), and improved respiratory quotient on the fed day. IF decreased gene expression of Leptin, but increased Adiponectin, β3ar (beta3 adrenoreceptor), and Ucp1 (uncoupling protein). IF enhanced immunostaining of Caspase 3, Pcna (proliferating cell nuclear antigen), and UCP1 in sWAT. IF attenuated pro-inflammatory markers and pro-apoptotic markers in sWAT.

CONCLUSIONS

IF in obese mice led to browning in sWAT adipocytes, enhanced thermogenesis, an improved adipose tissue pro-inflammatory profile.

NAFLD and cardiovascular diseases: a clinical review

Non-alcoholic fatty liver DISEASE (NAFLD) is the most common chronic liver disease in Western countries and affects approximately 25% of the adult population. Since NAFLD is frequently associated with further metabolic comorbidities such as obesity, type 2 diabetes mellitus, or dyslipidemia, it is generally considered as the hepatic manifestation of the metabolic syndrome. In addition to its potential to cause liver-related morbidity and mortality, NAFLD is also associated with subclinical and clinical cardiovascular disease (CVD). Growing evidence indicates that patients with NAFLD are at substantial risk for the development of hypertension, coronary heart disease, cardiomyopathy, and cardiac arrhythmias, which clinically result in increased cardiovascular morbidity and mortality. The natural history of NAFLD is variable and the vast majority of patients will not progress from simple steatosis to fibrosis and end stage liver disease. However, patients with progressive forms of NAFLD, including non-alcoholic steatohepatitis (NASH) and/or advanced fibrosis, as well as NAFLD patients with concomitant types 2 diabetes are at highest risk for CVD. This review describes the underlying pathophysiological mechanisms linking NAFLD and CVD, discusses the role of NAFLD as a metabolic dysfunction associated cardiovascular risk factor, and focuses on common cardiovascular manifestations in NAFLD patients.

Fructose-mediated effects on gene expression and epigenetic mechanisms associated with NAFLD pathogenesis

Nonalcoholic fatty liver disease (NAFLD) is a chronic, frequently progressive condition that develops in response to excessive hepatocyte fat accumulation (i.e., steatosis) in the absence of significant alcohol consumption. Liver steatosis develops as a result of imbalanced lipid metabolism, driven largely by increased rates of de novo lipogenesis and hepatic fatty acid uptake and reduced fatty acid oxidation and/or disposal to the circulation. Fructose is a naturally occurring simple sugar, which is most commonly consumed in modern diets in the form of sucrose, a disaccharide comprised of one molecule of fructose covalently bonded with one molecule of glucose. A number of observational and experimental studies have demonstrated detrimental effects of dietary fructose consumption not only on diverse metabolic outcomes such as insulin resistance and obesity, but also on hepatic steatosis and NAFLD-related fibrosis. Despite the compelling evidence that excessive fructose consumption is associated with the presence of NAFLD and may even promote the development and progression of NAFLD to more clinically severe phenotypes, the molecular mechanisms by which fructose elicits effects on dysregulated liver metabolism remain unclear. Emerging data suggest that dietary fructose may directly alter the expression of genes involved in lipid metabolism, including those that increase hepatic fat accumulation or reduce hepatic fat removal. The aim of this review is to summarize the current research supporting a role for dietary fructose intake in the modulation of transcriptomic and epigenetic mechanisms underlying the pathogenesis of NAFLD.

Association between Non-Alcoholic Fatty Liver Disease and Dietary Habits, Stress, and Health-Related Quality of Life in Korean Adults

Considering the increasing prevalence of non-alcoholic fatty liver disease (NAFLD), this study aimed to evaluate the association between NAFLD and dietary habits, stress, and health-related quality of life (HRQoL) in Korean individuals by using data from the Korea National Health and Nutrition Examination Survey (KNHANES) VI 2013-2015. NAFLD was defined in individuals with a hepatic steatosis index (HSI) value ≥36. Eating habits were assessed based on the frequencies of eating and eating out; stress was assessed through the stress perception rate; and the EuroQol-5D (EQ-5D) questionnaire was used to assess the HRQoL. We performed a complex sample logistic regression analysis and estimated the odds ratios by adjusting for significant factors to evaluate associations between NAFLD and dietary habits, stress, and HRQoL. Occurrence of NAFLD was not significantly associated with meal frequencies over one week. With an increase in stress, based on the stress perception rate, the risk of NAFLD increased 1.316-fold (95% confidence interval (CI): 1.175-1.469, p < 0.05). Additionally, a decrease in the EQ-5D score by 1 increased the risk of NAFLD 3.38-fold (95% CI: 1.893-4.844, p < 0.05). Thus, NAFLD treatment should include stress management, and underlying HRQoL should be considered during treatment.

Intermittent fasting, adipokines, insulin sensitivity, and hypothalamic neuropeptides in a dietary overload with high-fat or high-fructose diet in mice

The intermittent fasting (IF) might have benefits on metabolism and food intake. Twelve-week old C57BL/6 J mice were fed a control diet (C, 10% kcal fat), a high-fat diet (HF, 50% kcal fat) or a high-fructose diet (HFru, 50% kcal fructose) for 8 weeks, then half of the animals in each group underwent IF (24 h fed, 24 h fasting) for an additional 4 weeks. Although food intake on the fed day remained the same for all groups, all fasting groups showed a reduction in body mass compared to their counterparts. IF reduced total cholesterol, triacylglycerol, fasting glucose, fasting insulin resistance index, and plasma leptin, but increased plasma adiponectin. IF reduced Leptin gene expression in the HF-IF group, but increased proinflammatory markers in the hypothalamus, also in the C-IF group. Both groups HFru-IF and C-IF, showed alterations in the leptin signaling pathway (Leptin, OBRb, and SOCS3), mainly in the HFru-IF group, suggesting leptin resistance. NPY and POMC neuropeptides labeled the neurons of the hypothalamus by immunofluorescence, corroborating qualitatively other quantitative findings of the study. In conclusion, current results are convincing in demonstrating the IF effect on central regulation of food intake control, as shown by NPY and POMC neuropeptide expressions, resulting in a lower weight gain. Besides, IF improves glycemia, lipid metabolism, and consequently insulin and leptin resistance. However, there is increased expression of inflammatory markers in mouse hypothalamus challenged by the HF and HFru diets, which in the long term may induce adverse effects.

Intermittent fasting benefits on alpha- and beta-cell arrangement in diet-induced obese mice pancreatic islet

AIMS

There is a pancreatic islet adaptation in obese subjects, resulting in insulin resistance and diabetes type 2. We studied the effect of intermittent fasting (IntF) on the islet structure of diet-induced obese (DIO) mice.

METHODS

Three-month-old male mice fed a control diet (C, 10% Kcal fat) or a high-fat diet (HF, 50% Kcal fat) for two months (n = 20 each group). Then, half of each group did IntF (alternating 24 h fed/24 h fast), continuing in their diets four more weeks: C, C-IntF, HF, HF-IntF. Islets were prepared to microscopy or isolated for molecular analysis.

RESULTS

HF group (vs. C group) showed hyperglycemia, hyperinsulinemia, hyperleptinemia, hypoadiponectinemia, glucose intolerance, insulin resistance, and islet hypertrophy with a consequent higher both the alpha-cell and beta-cell masses. In the HF group (vs. C), there was low PDX1 (pancreatic and duodenal homeobox 1), and IntF did not alter PDX1. There was a low p-AKT/AKT ratio (protein kinase B), and IntF enhanced it. Also, tumor suppressor p53 was increased, and IntF decreased it. IL (interleukin) -6 was higher in the HF group (vs. C), and HF-IntF (vs. C-IntF). Any significant change in NFkB was seen among groups.

CONCLUSIONS

IntF improves pancreatic islet structure in DIO mice, even with continued HF diet intake, primarily considering on the alpha- and beta-cell masses regulation, then improving insulin signaling and decreasing cell apoptosis. Future research should explore whether the shortening of the IntF extend could maintain the benefits observed in the long term.