Potential mechanistic pathways underlying intestinal and hepatic effects of kefir in high-fructose-fed rats

The Counteracting Effect of Chrysin on Dietary Fructose-Induced Metabolic-Associated Fatty Liver Disease (MAFLD) in Rats with a Focus on Glucose and Lipid Metabolism

The prevalence of metabolic syndrome has been exponentially increasing in recent decades. Thus, there is an increasing need for affordable and natural interventions for this disorder. We explored the effect of chrysin, a dietary polyphenol, on hepatic lipid and glycogen accumulation, metabolic dysfunction-associated fatty liver disease (MAFLD) activity score and oxidative stress and on hepatic and adipose tissue metabolism in rats presenting metabolic syndrome-associated conditions. Rats fed a chow diet were separated into four groups: Control (tap water), Fructose (tap water with 10% fructose), Chrysin (tap water+ chrysin (100 mg/kg body weight/d)), and Fructose + Chrysin (tap water with 10% fructose + chrysin (100 mg/kg body weight/d, daily)) (for 18 weeks). When associated with the chow diet, chrysin reduced hepatic lipid and glycogen storage, increased the hepatic antioxidant potential of glutathione and reduced de novo lipogenesis in the adipose tissue. When associated with the high fructose-diet, chrysin attenuated the increase in lipid and glycogen hepatic storage, improved the MAFLD activity score, decreased hepatic lipid peroxidation, increased the antioxidant potential of glutathione, and improved lipid and glucose metabolic markers in the liver and adipose tissue. In conclusion, our results suggest that chrysin is a beneficial addition to a daily diet for improvement of hepatic metabolic health, particularly for individuals suffering from metabolic syndrome.

Fructose catabolism and its metabolic effects: Exploring host-microbiota interactions and the impact of ethnicity

Important health disparities are observed in the prevalence of obesity and associated non-communicable diseases (NCDs), including type 2 diabetes (T2D) and metabolic dysfunction-associated steatotic liver disease (MASLD) among ethnic groups. Yet, the underlying factors accounting for these disparities remain poorly understood. Fructose has been widely proposed as a potential mediator of these NCDs, given that hepatic fructose catabolism can result in deleterious metabolic effects, including insulin resistance and hepatic steatosis. Moreover, the fermentation of fructose by the gut microbiota can produce metabolites such as ethanol and acetate, both which serve as potential substrates for de novo lipogenesis (DNL) and could therefore contribute to the development of these metabolic conditions. Significant inter-ethnic differences in gut microbiota composition have been observed. Moreover, fructose consumption varies across ethnic groups, and fructose intake has been demonstrated to significantly alter gut microbiota composition, which can influence its fermenting properties and metabolic effects. Therefore, ethnic differences in gut microbiota composition, which may be influenced by variations in fructose consumption, could contribute to the observed health disparities. This review provides an overview of the complex interactions between host and microbial fructose catabolism, the role of ethnicity in shaping these metabolic processes and their impact on host health. Understanding these interactions could provide insights into the mechanisms driving ethnic health disparities to improve personalized nutrition strategies. KEY POINTS: Dietary fructose consumption has increased substantially over recent decades, which has been associated with the rising prevalence of obesity and non-communicable diseases (NCDs) such as type 2 diabetes and metabolic dysfunction-associated steatotic liver disease. Pronounced disparities among different ethnic groups in NCD prevalence and dietary fructose consumption underscore the need to elucidate the underlying mechanisms of fructose catabolism and its health effects. Together with the well-known toxic effects of hepatic fructose catabolism, emerging evidence highlights a role for the small intestinal microbiota in fermenting sugars like fructose into various bacterial products with potential deleterious metabolic effects. There are significant ethnic differences in gut microbiota composition that, combined with varying fructose consumption, could mediate the observed health disparities. To comprehensively understand the role of the gut microbiota in mediating fructose-induced adverse metabolic effects, future research should focus on the small intestinal microbiota. Future research on fructose - microbiota - host interactions should account for ethnic differences in dietary habits and microbial composition to elucidate the potential role of the gut microbiota in driving the mentioned health disparities.

Dietary Influences on Gut Microbiota and Their Role in Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major contributor to liver-related morbidity, cardiovascular disease, and metabolic complications. Lifestyle interventions, including diet and exercise, are first line in treating MASLD. Dietary approaches such as the low-glycemic-index Mediterranean diet, the ketogenic diet, intermittent fasting, and high fiber diets have demonstrated potential in addressing the metabolic dysfunction underlying this condition. The development and progression of MASLD are closely associated with taxonomic shifts in gut microbial communities, a relationship well-documented in the literature. Given the importance of diet as a primary treatment for MASLD, it is important to understand how gut microbiota and their metabolic byproducts mediate favorable outcomes induced by healthy dietary patterns. Conversely, microbiota changes conferred by unhealthy dietary patterns such as the Western diet may induce dysbiosis and influence steatotic liver disease through promoting hepatic inflammation, up-regulating lipogenesis, dysregulating bile acid metabolism, increasing insulin resistance, and causing oxidative damage in hepatocytes. Although emerging evidence has identified links between diet, microbiota, and development of MASLD, significant gaps remain in understanding specific microbial roles, metabolite pathways, host interactions, and causal relationships. Therefore, this review aims to provide mechanistic insights into the role of microbiota-mediated processes through the analysis of both healthy and unhealthy dietary patterns and their contribution to MASLD pathophysiology. By better elucidating the interplay between dietary nutrients, microbiota-mediated processes, and the onset and progression of steatotic liver disease, this work aims to identify new opportunities for targeted dietary interventions to treat MASLD efficiently.

The Role of Diet, Additives, and Antibiotics in Metabolic Endotoxemia and Chronic Diseases

Background/Objectives: Dietary patterns, including high-fat and high-carbohydrate diets (HFDs and HCDs), as well as non-dietary factors such as food additives and antibiotics, are strongly linked to metabolic endotoxemia, a critical driver of low-grade chronic inflammation. This review explores the mechanisms through which these factors impair intestinal permeability, disrupt gut microbial balance, and facilitate lipopolysaccharide (LPS) translocation into the bloodstream, contributing to metabolic disorders such as obesity, type 2 diabetes mellitus, and inflammatory bowel disease. Methods: The analysis integrates findings from recent studies on the effects of dietary components and gut microbiota interactions on intestinal barrier function and systemic inflammation. Focus is given to experimental designs assessing gut permeability using biochemical and histological methods, alongside microbiota profiling in both human and animal models. Results: HFDs and HCDs were shown to increase intestinal permeability and systemic LPS levels, inducing gut dysbiosis and compromising barrier integrity. The resulting endotoxemia promoted a state of chronic inflammation, disrupting metabolic regulation and contributing to the pathogenesis of various metabolic diseases. Food additives and antibiotics further exacerbated these effects by altering microbial composition and increasing gut permeability. Conclusions: Diet-induced alterations in gut microbiota and barrier dysfunction emerge as key mediators of metabolic endotoxemia and related disorders. Addressing dietary patterns and their impact on gut health is crucial for developing targeted interventions. Further research is warranted to standardize methodologies and elucidate mechanisms for translating these findings into clinical applications.

Impact of high-fructose diet and metformin on histomorphological and molecular parameters of reproductive organs and vaginal microbiota of female rat

There are limited data on the effects of a high-fructose diet on the female reproductive system. Although metformin has some functional effects on female fertility, its reproductive outcome on high fructose diet-induced metabolic syndrome is unclear. The aim of the present study is to evaluate the impact of a high fructose diet on histomorphological and molecular parameters of the reproductive organs and vaginal microbiota as well as the treatment potential of metformin. Wistar albino rats were used in the study. The metabolic syndrome model was induced by a high-fructose diet in rats for 15 weeks. Metformin was orally administered once a day for the last 6 weeks. The high-fructose diet increased blood glucose, triglycerides, insulin, and ovarian testosterone levels; however, it reduced ovarian aromatase levels and follicle numbers and caused uterine inflammation. The high-fructose diet-induced molecular abnormalities on ovarian tissue were demonstrated by the downregulation of ovarian insulin signaling pathway proteins and dysregulation of ovarian mitogenic and apoptotic pathway proteins. A high-fructose diet caused vaginal dysbiosis, metformin increased probiotic bacteria in the vaginal microbiota. Our results revealed that metformin improves ovarian impairments by modulating hormonal balance, insulin level, mapk, and apoptotic signaling molecules, as well as regulating the vaginal microbiota.

Anti-inflammatory pathways of kefir in murine model: a systematic review

CONTEXT

Kefir consumption has been associated with immune response modulation, antioxidant, and anti-inflammatory effects.

OBJECTIVE

The objective of this systematic review was to investigate the role of kefir against inflammation and the main response mechanisms involved in this process in a murine model.

DATA SOURCES

The searches were searched in the PubMed, Science Direct, and LILACS databases. Only murine model studies, according to PRISMA guidelines, published in the past 10 years were included.

STUDY SELECTION

Only articles about original and placebo-controlled experiments in murine models used to investigate the anti-inflammatory mechanisms of kefir were considered. Of the articles found, 349 were excluded according to the following criteria: duplicate articles (n = 99), off-topic title and abstract (n = 157), reviews (n = 47), studies in vitro (n = 29), and studies with humans (n = 17). In total, 23 studies were included in this review.

DATA EXTRACTION

Two independently working authors assessed the risk of bias and extracted data from the included studies.

RESULTS

Kefir consumption had positive effects on inflammation modulation. The main mechanisms involved were the reduction of pro-inflammatory and molecular markers; reduction in inflammatory infiltrate in tissues, serum biomarkers, risk factors for chronic diseases, and parasitic infection; composition and metabolic activity change of intestinal microbiota and mycobiota; activation of humoral and cellular immunity; and modulation of oxidative stress.

CONCLUSIONS

Kefir modulates the immune system in different experimental models, among other secondary outcomes, to improve overall health. The beverage reduces inflammation through the alternation between innate, Th1, and Th2 responses, reducing levels of pro-inflammatory cytokines while increasing those of anti-inflammatory ones. In addition, it also mediates immunomodulatory and protective effects through the numerous molecular biomarkers and organic acids produced and secreted by kefir in the intestinal microbiota. The health-promoting effects attributed to kefir may help in the different treatments of inflammatory, chronic, and infectious diseases in the population.

The impact of dietary fructose on gut permeability, microbiota, abdominal adiposity, insulin signaling and reproductive function

The excessive intake of fructose in the regular human diet could be related to global increases in metabolic disorders. Sugar-sweetened soft drinks, mostly consumed by children, adolescents, and young adults, are the main source of added fructose. Dietary high-fructose can increase intestinal permeability and circulatory endotoxin by changing the gut barrier function and microbial composition. Excess fructose transports to the liver and then triggers inflammation as well as de novo lipogenesis leading to hepatic steatosis. Fructose also induces fat deposition in adipose tissue by stimulating the expression of lipogenic genes, thus causing abdominal adiposity. Activation of the inflammatory pathway by fructose in target tissues is thought to contribute to the suppression of the insulin signaling pathway producing systemic insulin resistance. Moreover, there is some evidence that high intake of fructose negatively affects both male and female reproductive systems and may lead to infertility. This review addresses dietary high-fructose-induced deteriorations that are obvious, especially in gut permeability, microbiota, abdominal fat accumulation, insulin signaling, and reproductive function. The recognition of the detrimental effects of fructose and the development of relevant new public health policies are necessary in order to prevent diet-related metabolic disorders.

In vitro antifungal and antibiofilm activities of novel sulfonyl hydrazone derivatives against Candida spp

BACKGROUND

The aim of this study was to investigate the antifungal and antibiofilm activity of the new sulfonyl hydrazones compound derived from sulphonamides.

METHODS

In this study, new sulfonyl hydrazone series were synthesized via a green chemistry method. The structures of the synthesized compounds were characterized by elemental analyses and spectroscopic methods. The antifungal activities of the Anaf compounds against Candida strains under planktonic conditions were tested. The biofilm-forming ability of Candida strains was determined and the inhibitory effects of Anaf compounds on Candida biofilms compared with fluconazole were measured by MTT assay. Expression analysis of biofilm-related genes was investigated with qRT-PCR. The statistical analysis was performed using a one-way ANOVA test. CANDIDA: strains was determined and the inhibitory effects of Anaf compounds on Candida biofilms compared with fluconazole were measured by MTT assay. Expression analysis of biofilm-related genes was investigated with qRT-PCR. The statistical analysis was performed using a one-way ANOVA test.

RESULTS

A total of 16 (45.7%) out of 35 Candida isolates were determined as strong biofilm producers in this study. C. albicans was the most biofilm producer, followed by C. krusei and C. lusitaniae. The Anaf compounds had a broad spectrum of activity with MIC values ranging from 4 μg/ml to 64 μg/ml. Our data indicated that the Anaf compound had a significant effect on inhibiting biofilm formation in both fluconazole-susceptible and -resistant strains. The expression levels of hypha-specific genes als3, hwp1, ece1 and sap5 were downregulated by Anaf compounds.

CONCLUSIONS

Our study revealed that the Anaf compounds had antifungal activity and inhibited fungal biofilms, which may be related to the suppression of C. albicans adherence and hyphal formation. These results suggest that Anaf compounds may have therapeutic potential for the treatment and prevention of biofilm-associated Candida infections.

Effect of chronic administration of 17β-estradiol on the vasopressor responses induced by the sympathetic nervous system in insulin resistance rats

Several studies have demonstrated that the underlying mechanism of insulin resistance (IR) is linked with developing diseases like diabetes mellitus, hypertension, metabolic syndrome, and polycystic ovary syndrome. In turn, the dysfunction of female gonadal hormones (especially 17β-estradiol) may be related to the development of IR complications since different studies have shown that 17β-estradiol has a cardioprotector and vasorelaxant effect. This study aimed was to determine the effect of the 17β-estradiol administration in insulin-resistant rats and its effects on cardiovascular responses in pithed rats. Thus, the vasopressor responses are induced by sympathetic stimulation or i.v. bolus injections of noradrenaline (α_1/2), methoxamine (α₁), and UK 14,304 (α₂) adrenergic agonist were determined in female pithed rats with fructose-induced insulin resistance or control rats treated with: 1) 17β-estradiol or 2) its vehicle (oil) for 5 weeks. Thus, 17β-estradiol decreased heart rate, prevented the increase of blood pressure induced by ovariectomy, but with the opposite effect on sham-operated rats; and decreased vasopressor responses induced by i.v. bolus injections of noradrenaline on sham-operated (control and fructose group) and ovariectomized (control) rats, and those induced by i.v. bolus injections of methoxamine (α₁ adrenergic agonist). Overall, these results suggest 17β-estradiol has a cardioprotective effect, and its effect on vasopressor responses could be mediated mainly by the α1 adrenergic receptor. In contrast, IR with ovariectomy 17β-estradiol decreases or loses its cardioprotector effect, this could suggest a possible link between the adrenergic receptors and the insulin pathway.

Microbial Communities in Home-Made and Commercial Kefir and Their Hypoglycemic Properties

Kefir is a popular traditional fermented dairy product in many countries. It has a complex and symbiotic culture made up of species of the genera Leuconostoc, Lactococcus, and Acetobacter, as well as Lactobacilluskefiranofaciens and Lentilactobacillus kefiri. Though kefir has been commercialized in some countries, people are still traditionally preparing kefir at the household level. Kefir is known to have many nutritious values, where its consistent microbiota has been identified as the main valuable components of the product. Type 2 diabetes mellitus (T2DM) is a common diet-related disease and has been one of the main concerns in the world’s growing population. Kefir has been shown to have promising activities in T2DM, mostly via hypoglycemic properties. This review aims to explain the microbial composition of commercial and home-made kefir and its possible effects on T2DM. Some studies on animal models and human clinical trials have been reviewed to validate the hypoglycemic properties of kefir. Based on animal and human studies, it has been shown that consumption of kefir reduces blood glucose, improves insulin signaling, controls oxidative stress, and decreases progression of diabetic nephropathy. Moreover, probiotic bacteria such as lactic-acid bacteria and Bifidobacterium spp. and their end-metabolites in turn directly or indirectly help in controlling many gut disorders, which are also the main biomarkers in the T2DM condition and its possible treatment.

Nicotinamide riboside ameliorates high-fructose-induced lipid metabolism disorder in mice via improving FGF21 resistance in the liver and white adipose tissue

NR supplementation could ameliorate high-fructose-induced lipid metabolism disorder by improving FGF21 resistance in the liver and WAT, which may be related to the inflammation state mediated by SIRT1/NF-κB signaling pathway.

Kefir alters craniomandibular bone development in rats fed excess dose of high fructose corn syrup

INTRODUCTION

Dietary high fructose corn syrup (HFCS) is involved in the pathogenesis of oral diseases as well as metabolic diseases. The aim of this study was to investigate the effects of HFCS-feeding on the craniomandibular bone development at an early age and also the potential of milk kefir for preventive treatment.

MATERIALS AND METHODS

In this study, Control, Kefir, HFCS, and HFCS plus Kefir groups were formed; kefir was given by gastric gavage, while HFCS (20% beverages) was given in drinking water; for 8 weeks.

RESULTS

Based on morphological evaluations, immunohistochemical, and gene expression results, it was clearly determined that excess dose of HFCS consumption decreased osteoblastic activity in craniomandibular bones while increasing osteoclastic activity. However, it has been determined that the intake of kefir with the HFCS-feeding greatly suppresses the effects of HFCS on bone tissues.

CONCLUSION

In conclusion, dietary the excess dose of HFCS at an early age has been observed to pose a risk for cranial and mandible bone development. The healing effects of kefir may be a new approach to the treatment via kefir consumption in young's.

Potential protective mechanism of Tibetan kefir underlying gut-derived liver injury induced by ochratoxin A

Tibetan kefir against Ochratoxin A-induced liver injury by maintaining the intestinal barrier and modulating the gut microbiota and metabolites.

Dietary high-fructose reduces barrier proteins and activates mitogenic signalling in the testis of a rat model: Regulatory effects of kefir supplementation

There are limited data on the influence of fructose rich diet on the male reproductive system. Kefir may have health beneficial effects, but its mechanism of action remains mostly unclear. Herein, we investigated the impact of dietary high fructose on tight junction proteins and mitogenic pathways in rat testis as well as their modulation by kefir supplementation. Twenty-two male Wistar rats (4 weeks old) were divided into the following three groups: Control; Fructose; Fructose + Kefir. Fructose was added to drinking water at concentration of 20% and administered to the rats for 15 weeks and kefir was supplemented by gavage once a day during final 6 weeks. Dietary fructose-induced testicular degeneration was associated with the downregulation of the blood-testis barrier proteins, claudin-11 and N-cadherin as well as SIRT1 expression in testicular tissue of rats. However, p38MAPK, p-p38MAPK and p-ERK1/2 levels were increased in testis of fructose-fed rats. Interestingly, JNK1 and p-JNK1 protein levels were decreased following this dietary intervention. Raf1, ERK1/2, and caspase 3 and TUNEL staining of the testis reveal the activation of apoptosis due to fructose intake. Kefir supplementation markedly promoted the expression of claudin-11, SIRT1, JNK1 and p-JNK1 but suppressed testicular mitogenic and apoptotic factors in fructose-fed rats.

The Contribution of Dietary Fructose to Non-alcoholic Fatty Liver Disease

Fructose, especially industrial fructose (sucrose and high fructose corn syrup) is commonly used in all kinds of beverages and processed foods. Liver is the primary organ for fructose metabolism, recent studies suggest that excessive fructose intake is a driving force in non-alcoholic fatty liver disease (NAFLD). Dietary fructose metabolism begins at the intestine, along with its metabolites, may influence gut barrier and microbiota community, and contribute to increased nutrient absorption and lipogenic substrates overflow to the liver. Overwhelming fructose and the gut microbiota-derived fructose metabolites (e.g., acetate, butyric acid, butyrate and propionate) trigger the de novo lipogenesis in the liver, and result in lipid accumulation and hepatic steatosis. Fructose also reprograms the metabolic phenotype of liver cells (hepatocytes, macrophages, NK cells, etc.), and induces the occurrence of inflammation in the liver. Besides, there is endogenous fructose production that expands the fructose pool. Considering the close association of fructose metabolism and NAFLD, the drug development that focuses on blocking the absorption and metabolism of fructose might be promising strategies for NAFLD. Here we provide a systematic discussion of the underlying mechanisms of dietary fructose in contributing to the development and progression of NAFLD, and suggest the possible targets to prevent the pathogenetic process.