The Effects of Gum Acacia on the Composition of the Gut Microbiome and Plasma Levels of Short-Chain Fatty Acids in a Rat Model of Chronic Kidney Disease

The protective role of phlorizin against lipopolysaccharide-induced acute orchitis in mice associated with changes in gut microbiota composition

Objective

Orchitis is a common reproductive disease of male animals, which has serious implications to human and animal reproduction. Additionally, phlorizin (PHN), a common polyphenol in apples and strawberries, has a variety of biological activities, including antioxidant, anti-inflammatory, anti-diabetic, and anti-aging activities. We aimed to determine the protective effects and potential mechanisms of PHN in lipopolysaccharide (LPS)-induced acute orchitis in mice.

Method

After 21 days of PHN pretreatment, mice were injected with LPS to induce testicular inflammation, and then the changes of testicular tissue structure, expression of inflammatory factors, testosterone level, expression of testosterone-related genes, adhesion gene and protein expression were detected, and the structural changes in the intestinal flora after PHN treatment were further detected by 16SRNA.

Result

Our results demonstrated that PHN treatment reduced LPS-induced testicular injury and body and testicular weight losses. The mRNA expression levels of pro-inflammatory cytokines-related genes and antioxidant enzyme activity were also decreased and elevated, respectively, by PHN administration; however, PHN treatment also reduced the LPS-induced decrease in testosterone levels in the testes. Additionally, further studies found that PHN increased the expression of marker proteins zonula occludens-1 (ZO-1) and occludin associated with the blood testosterone barrier compared with that in LPS treatment groups. To further examine the potential mechanisms of the protective effect of PHN on LPS-induced testicular injury, we compared the differences of gut microbiota compositions between the 100 mg/kg PHN treatment group and the control group using 16SRNA. Metagenomic analyses indicated that the abundances of Bacteroidetes, Muribaculaceae, Lactobacillaceae, uncultured bacterium f Muribaculaceae, and Lactobacillus in the PHN treatment group improved, while potential microbes that can induce intestinal diseases, including Verrucomicrobia, Epsilonbacteraeota, Akkermansiaceae, and Akkermansia decreased in the PHN treatment group.

Conclusion

Our results indicate that PHN pretreatment might alleviate orchitis by altering the composition of gut microflora, which may provide a reference for reducing the occurrence of acute orchitis in male animals.

Gum acacia dietary fiber: Significance in immunomodulation, inflammatory diseases, and cancer

Gum arabic/acacia (GA), derived from Acacia trees, is a versatile natural product offering a broad spectrum of applications. Its rich content of soluble dietary fibers, coupled with a low caloric profile, renders GA a valuable dietary component associated with numerous health benefits. Furthermore, its fermentation by gut microbiota yields short-chain fatty acids, renowned for their positive impact on health. Immunomodulation, a crucially regulated mechanism in the body, serves to fend off pathogenic infections by releasing pro-inflammatory cytokines. However, prolonged synthesis of these cytokines can lead to chronic inflammation, tissue damage, and potentially contribute to the development of autoimmune diseases and cancer. Hence, there is an urgent need to identify plant-based biomolecules that can effectively reduce inflammation and inhibit inflammation-induced complications or disorders. In this context, edible biomolecules like GA are gaining prominence for their noteworthy immunomodulatory properties. Therefore, in the present review we have explored the role of GA in immunomodulation, inflammation, and inflammation-associated metabolic diseases, and cancer.

Pharmacological benefits of Acacia against metabolic diseases: intestinal-level bioactivities and favorable modulation of gut microbiota

CONTEXT

Obesity-associated chronic metabolic disease is a leading contributor to mortality globally. Plants belonging to the genera Acacia are routinely used for the treatment of diverse metabolic diseases under different ethnomedicinal practices around the globe.

OBJECTIVE

The current review centres around the pharmacological evidence of intestinal-level mechanisms for metabolic health benefits by Acacia spp.

RESULTS

Acacia spp. increase the proportions of gut commensals (Bifidobacterium and Lactobacillus) and reduces the population of opportunistic pathobionts (Escherichia coli and Clostridium). Acacia gum that is rich in fibre, can also be a source of prebiotics to improve gut health. The intestinal-level anti-inflammatory activities of Acacia are likely to contribute to improvements in gut barrier function that would prevent gut-to-systemic endotoxin translocation and limit "low-grade" inflammation associated with metabolic diseases.

CONCLUSION

This comprehensive review for the first time has emphasised the intestinal-level benefits of Acacia spp. which could be instrumental in limiting the burden of metabolic disease.

The impact of common pharmaceutical excipients on the gut microbiota

INTRODUCTION

Increasing attention is being afforded to understanding the bidirectional relationships that exist between oral medications and the gut microbiota, in an attempt to optimize pharmacokinetic performance and mitigate unwanted side effects. While a wealth of research has investigated the direct impact of active pharmaceutical ingredients (APIs) on the gut microbiota, the interactions between inactive pharmaceutical ingredients (i.e. excipients) and the gut microbiota are commonly overlooked, despite excipients typically representing over 90% of the final dosage form.

AREAS COVERED

Known excipient-gut microbiota interactions for various classes of inactive pharmaceutical ingredients, including solubilizing agents, binders, fillers, sweeteners, and color additives, are reviewed in detail.

EXPERT OPINION

Clear evidence indicates that orally administered pharmaceutical excipients directly interact with gut microbes and can either positively or negatively impact gut microbiota diversity and composition. However, these relationships and mechanisms are commonly overlooked during drug formulation, despite the potential for excipient-microbiota interactions to alter drug pharmacokinetics and interfere with host metabolic health. The insights derived from this review will inform pharmaceutical scientists with the necessary design considerations for mitigating potential adverse pharmacomicrobiomic interactions when formulating oral dosage forms, ultimately providing clear avenues for improving therapeutic safety and efficacy.

Gut Dysbiosis in Experimental Kidney Disease: A Meta-Analysis of Rodent Repository Data

SIGNIFICANCE STATEMENT

Alterations in gut microbiota contribute to the pathophysiology of a diverse range of diseases, leading to suggestions that chronic uremia may cause intestinal dysbiosis that contributes to the pathophysiology of CKD. Various small, single-cohort rodent studies have supported this hypothesis. In this meta-analysis of publicly available repository data from studies of models of kidney disease in rodents, cohort variation far outweighed any effect of experimental kidney disease on the gut microbiota. No reproducible changes in animals with kidney disease were seen across all cohorts, although a few trends observed in most experiments may be attributable to kidney disease. The findings suggest that rodent studies do not provide evidence for the existence of "uremic dysbiosis" and that single-cohort studies are unsuitable for producing generalizable results in microbiome research.

BACKGROUND

Rodent studies have popularized the notion that uremia may induce pathological changes in the gut microbiota that contribute to kidney disease progression. Although single-cohort rodent studies have yielded insights into host-microbiota relationships in various disease processes, their relevance is limited by cohort and other effects. We previously reported finding metabolomic evidence that batch-to-batch variations in the microbiome of experimental animals are significant confounders in an experimental study.

METHODS

To attempt to identify common microbial signatures that transcend batch variability and that may be attributed to the effect of kidney disease, we downloaded all data describing the molecular characterization of the gut microbiota in rodents with and without experimental kidney disease from two online repositories comprising 127 rodents across ten experimental cohorts. We reanalyzed these data using the DADA2 and Phyloseq packages in R, a statistical computing and graphics system, and analyzed data both in a combined dataset of all samples and at the level of individual experimental cohorts.

RESULTS

Cohort effects accounted for 69% of total sample variance ( P <0.001), substantially outweighing the effect of kidney disease (1.9% of variance, P =0.026). We found no universal trends in microbial population dynamics in animals with kidney disease, but observed some differences (increased alpha diversity, a measure of within-sample bacterial diversity; relative decreases in Lachnospiraceae and Lactobacillus ; and increases in some Clostridia and opportunistic taxa) in many cohorts that might represent effects of kidney disease on the gut microbiota .

CONCLUSIONS

These findings suggest that current evidence that kidney disease causes reproducible patterns of dysbiosis is inadequate. We advocate meta-analysis of repository data as a way of identifying broad themes that transcend experimental variation.

Natural products from plants and microorganisms: Novel therapeutics for chronic kidney disease via gut microbiota regulation

Dysbiosis of gut microbiota plays a fundamental role in the pathogenesis and development of chronic kidney disease (CKD) and its complications. Natural products from plants and microorganisms can achieve recognizable improvement in renal function and serve as an alternative treatment for chronic kidney disease patients with a long history, yet less is known on its beneficial effects on kidney injury by targeting the intestinal microbiota. In this review, we summarize studies on the effects of natural products from plants and microorganisms, including herbal medicines and their bioactive extracts, polysaccharides from plants and microorganisms, and phytochemicals, on the prevention and treatment of chronic kidney disease through targeting gut microflora. We describe the strategies of these anti-CKD effects in animal experiments including remodulation of gut microbiota structure, reduction of uremic toxins, enhancement of short-chain fatty acid (SCFA) production, regulation of intestinal inflammatory signaling, and improvement in intestinal integrity. Meanwhile, the clinical trials of different natural products in chronic kidney disease clinical practice were also analyzed and discussed. These provide information to enable a better understanding of the renoprotective effects of these effective natural products from plants and microorganisms in the treatment of chronic kidney disease. Finally, we propose the steps to prove the causal role of the intestinal microflora in the treatment of chronic kidney disease by natural products from plants and microorganisms. We also assess the future perspective that natural active products from plants and microorganisms can beneficially delay the onset and progression of kidney disease by targeting the gut flora and highlight the remaining challenges in this area. With the continuous deepening of studies in recent years, it has been proved that gut microbiota is a potential target of natural active products derived from plants and microorganisms for chronic kidney disease treatment. Fully understanding the functions and mechanisms of gut microbiota in these natural active products from plants and microorganisms is conducive to their application as an alternative therapeutic in the treatment of chronic kidney disease.

Causal Effects of Specific Gut Microbiota on Chronic Kidney Diseases and Renal Function-A Two-Sample Mendelian Randomization Study

BACKGROUND

Targeting the gut microbiota may become a new therapeutic to prevent and delay the progression of chronic kidney disease (CKD). Nonetheless, the causal relationship between specific intestinal flora and CKD is still unclear.

MATERIALS AND METHOD

To identify genetically predicted microbiota, we used summary data from genome-wide association studies on gut microbiota in 18340 participants from 24 cohorts. Furthermore, we genetically predicted the causal relationship between 211 gut microbiotas and six phenotypes (outcomes) (CKD, estimated glomerular filtration rate (eGFR), urine albumin to creatinine ratio (UACR), dialysis, rapid progress to CKD, and rapid decline of eGFR). Four Mendelian randomization (MR) methods, including inverse variance weighted (IVW), MR-Egger, weighted median, and weighted mode were used to investigate the casual relationship between gut microbiotas and various outcomes. The result of IVW was deemed as the primary result. Then, Cochrane's Q test, MR-Egger, and MR-PRESSO Global test were used to detect heterogeneity and pleiotropy. The leave-one method was used for testing the stability of MR results and Bonferroni-corrected was used to test the strength of the causal relationship between exposure and outcome.

RESULTS

Through the MR analysis of 211 microbiotas and six clinical phenotypes, a total of 36 intestinal microflora were found to be associated with various outcomes. Among them, Class Bacteroidia (=-0.005, 95% CI: -0.001 to -0.008, p = 0.002) has a strong causality with lower eGFR after the Bonferroni-corrected test, whereas phylum Actinobacteria (OR = 1.0009, 95%CI: 1.0003-1.0015, p = 0.0024) has a strong causal relationship with dialysis. The Cochrane's Q test reveals that there is no significant heterogeneity between various single nucleotide polymorphisms. In addition, no significant level of pleiotropy was found according to MR-Egger and MR-PRESSO Global tests.

CONCLUSIONS

Through the two-sample MR analysis, we identified the specific intestinal flora that has a causal relationship with the incidence and progression of CKD at the level of gene prediction, which may provide helpful biomarkers for early disease diagnosis and potential therapeutic targets for CKD.

Gut–Kidney Axis Investigations in Animal Models of Chronic Kidney Disease

Chronic kidney disease (CKD) is an incurable disease in which renal function gradually declines, resulting in no noticeable symptoms during the early stages and a life-threatening disorder in the latest stage. The changes that accompany renal failure are likely to influence the gut microbiota, or the ecosystem of micro-organisms resident in the intestine. Altered gut microbiota can display metabolic changes and become harmful to the host. To study the gut–kidney axis in vivo, animal models should ideally reproduce the disorders affecting both the host and the gut microbiota. Murine models of CKD, but not dog, manifest slowed gut transit, similarly to patient. Animal models of CKD also reproduce altered intestinal barrier function, as well as the resulting leaky gut syndrome and bacterial translocation. CKD animal models replicate metabolic but not compositional changes in the gut microbiota. Researchers investigating the gut–kidney axis should pay attention to the selection of the animal model (disease induction method, species) and the setting of the experimental design (control group, sterilization method, individually ventilated cages) that have been shown to influence gut microbiota.

Evaluation of gum Arabic (Acacia Senegal) as a natural prebiotic to improve growth performance and health status of broiler chickens

Gum Arabic (GA) is a natural product containing soluble fiber that is indigestible in the gastrointestinal tract and has been used as a traditional medicine to treat many diseases such as intestinal inflammation, kidney disease, and liver disorders, which may be reflected in the improved performance of broiler chickens when used. Therefore, the main objective of the current study was to evaluate the effects of GA on the performance, immune system, visceral organs, functional tests, and histological changes of the ileum, liver, and kidneys of broilers. A total of 432 1-day-old male broilers were allocated to six dietary treatments (0.0, 0.12, 0.25, 0.5, 0.75, and 1.0% GA) for 35 days. Performance, internal organs, and blood biochemical indices were measured. Morphology and histometry of the intestine were also performed. Meanwhile, tissues of the ileum, liver, and kidney were examined and evaluated microscopically to observe histological changes. All levels of GA (0.12 to 1.0%) had a positive effect on growth performance and feed conversion ratio. In addition, GA had no effect on the relative weight of lymphoid and visceral organs, except for a linear response in the bursa and liver. The levels of GA (0.12 and 0.25%) showed the potential to decrease serum uric acid, creatinine, and alanine aminotransferase. The remarkable increase in small intestinal morphology of chickens fed GA and an increase in all histometric values of the ileum. All histological changes in the intestine, liver, and kidneys improved in chickens fed the basal diet containing 0.12 to 0.50% GA. These results provide useful evidence for the potential use of GA powder (Acacia senegal) as a natural prebiotic to improve performance and intestinal, liver, and kidney health in broiler chickens.

Recent advances of gut microbiota in chronic kidney disease patients

Chronic kidney disease (CKD) is a worldwide public health issue and has ultimately progressed to an end-stage renal disease that requires life-long dialysis or renal transplantation. However, the underlying molecular mechanism of these pathological development and progression remains to be fully understood. The human gut microbiota is made up of approximately 100 trillion microbial cells including anaerobic and aerobic species. In recent years, more and more evidence has indicated a clear association between dysbiosis of gut microbiota and CKD including immunoglobulin A (IgA) nephropathy, diabetic kidney disease, membranous nephropathy, chronic renal failure and end-stage renal disease. The current review describes gut microbial dysbiosis and metabolites in patients with CKD thus helping to understand human disease. Treatment with prebiotics, probiotics and natural products can attenuate CKD through improving dysbiosis of gut microbiota, indicating a novel intervention strategy in patients with CKD. This review also discusses therapeutic options, such as prebiotics, probiotics and natural products, for targeting dysbiosis of gut microbiota in patients to provide more specific concept-driven therapy strategy for CKD treatment.

Faecal Microbiota Transplantation and Chronic Kidney Disease

Faecal microbiota transplantation (FMT) has attracted increasing attention as an intervention in many clinical conditions, including autoimmune, enteroendocrine, gastroenterological, and neurological diseases. For years, FMT has been an effective second-line treatment for Clostridium difficile infection (CDI) with beneficial outcomes. FMT is also promising in improving bowel diseases, such as ulcerative colitis (UC). Pre-clinical and clinical studies suggest that this microbiota-based intervention may influence the development and progression of chronic kidney disease (CKD) via modifying a dysregulated gut–kidney axis. Despite the high morbidity and mortality due to CKD, there are limited options for treatment until end-stage kidney disease occurs, which results in death, dialysis, or kidney transplantation. This imposes a significant financial and health burden on the individual, their families and careers, and the health system. Recent studies have suggested that strategies to reverse gut dysbiosis using FMT are a promising therapy in CKD. This review summarises the preclinical and clinical evidence and postulates the potential therapeutic effect of FMT in the management of CKD.

Tongbixiao Pills Improve Gout by Reducing Uric Acid Levels and Inhibiting Inflammation

Gout is a chronic disease. Gout symptoms are often experienced in the middle of the night. The onset of gout in the middle of the night is closely related to abnormal liver and gallbladder meridian. The purpose of this study was to investigate the clinical efficacy and possible mechanism of action of Tongbixiao pills in the treatment of hyperuricemia and gouty arthritis. The Tongbixiao pills we used included several traditional Chinese medicines, most of which tonify the spleen; strengthen the liver; benefit the kidney; and reduce heat, dampness, and blood stasis. In this randomized clinical study of 105 patients, we found that Tongbixiao pills can reduce uric acid levels in hyperuricemia patients. Additionally, the efficacy was similar to that of allopurinol and the level of uric acid did not increase significantly at eight weeks after withdrawal. In the absence of notable adverse reactions, Tongbixiao pills can also increase uric acid excretion, reduce serum creatinine and lipid levels, and reduce inflammation and relieve gout symptoms. In addition, we used SD rats to simulate gout and arthritis and divided them into five groups: normal group, model group, low-dose group, medium-dose group, and high-dose group. The inflammatory indices of the 40 SD rats were observed. After seven days, ankle swelling in rats in the treatment group was significantly reduced. The indices of uric acid, creatinine, and urea nitrogen in the treatment group were significantly lower than those in the model group, which proved that Tongbixiao pills could inhibit hyperuricemia in rats, thus treating gout. This study demonstrates that Tongbixiao pills can treat gout, provide more treatment options for gouty arthritis, and improve the quality of life of patients.

Gum Arabic Supplementation Suppresses Colonic Fibrosis After Acute Colitis by Reducing Transforming Growth Factor β1 Expression

Ulcerative colitis is a chronic inflammation of the colonic mucosa. Gum Arabic (GA) has been reported to exert anti-inflammatory and antifibrotic activity. This study aimed to evaluate the effect of GA on disease activity in an experimental model of colitis. Dextran sodium sulfate (DSS) was used to induce colitis in C57BL/6 mice and the animals were then switched to normal drinking water to monitor recovery. Mice received 140 g/L GA before (pre-GA group) or after (post-GA group) induction of colitis. Disease activity and recovery were assessed by changes in body weight, disease activity index (DAI), and histological assessment. Gene expression of proinflammatory, anti-inflammatory, and fibrotic markers was measured in colonic tissues. Mice in the pre-GA group showed an increase in body weight, with no differences in DAI scores, during the recovery phase and had lower histological colitis scores than mice in the post-GA group, which showed higher DAI and histological scores during the recovery phase. During the recovery phase, mice in the pre-GA group showed increased expression of proinflammatory markers, while gene expression of the fibrotic markers, transforming growth factor β1 (TGFβ1) and procollagen I, was reduced. The reduced fibrotic marker expression was associated with reduced collagen staining and increased epithelial cell proliferation. Administration of GA had protective and alleviative effects on the severity of DSS-induced colitis, with a reduction in colonic fibrosis and TGFβ1 expression. These data warrant further in vitro and in vivo investigations on the effect of GA on fibroblast activity.