Calcium Reduces Liver Injury in Mice on a High-Fat Diet: Alterations in Microbial and Bile Acid Profiles

Progress of linking gut microbiota and musculoskeletal health: casualty, mechanisms, and translational values

The musculoskeletal system is important for balancing metabolic activity and maintaining health. Recent studies have shown that distortions in homeostasis of the intestinal microbiota are correlated with or may even contribute to abnormalities in musculoskeletal system function. Research has also shown that the intestinal flora and its secondary metabolites can impact the musculoskeletal system by regulating various phenomena, such as inflammation and immune and metabolic activities. Most of the existing literature supports that reasonable nutritional intervention helps to improve and maintain the homeostasis of intestinal microbiota, and may have a positive impact on musculoskeletal health. The purpose of organizing, summarizing and discussing the existing literature is to explore whether the intervention methods, including nutritional supplement and moderate exercise, can affect the muscle and bone health by regulating the microecology of the intestinal flora. More in-depth efficacy verification experiments will be helpful for clinical applications.

Relationship between dietary intake components and hepatic fibrosis in those with obesity before and 1 year after bariatric surgery

OBJECTIVES

Non-alcoholic fatty liver disease is highly prevalent in the bariatric population but not all patients develop liver fibrosis. Considering that fibrosis may affect clinical outcomes, it is important to assess and treat contributing factors. In this population, it is not clear whether dietary intake is a contributor. The objective was to determine the relationship between dietary intake components and liver fibrosis before and 1 y after Roux-en-Y gastric bypass (RYGB).

METHODS

This was a prospective cross-sectional (n = 133) study conducted between 2013 and 2022. In addition, a subgroup of 44 patients were followed for 1 y post-RYGB. Anthropometrics, biochemical measurements, and 3-d food records and liver biopsies were obtained presurgery and, in a subgroup of patients, as for the cohort, 1 y post-RYGB.

RESULTS

In the cross-sectional study, 78.2% were female, with a median age of 48 y and body mass index of 46.8 kg/m2; 33.8% had type 2 diabetes mellitus and 57.1% had metabolic syndrome. In a multivariate analysis, age (odds ratio; 95% CI) (1.076; 1.014-1.141), alanine transaminase (1.068; 1.025-1.112), calorie intake (1.001; 1.000-1.002), and dietary copper (0.127; 0.022-0.752) were independently associated with fibrosis (<0.05). At 1 y post-RYGB, no independent risk factors were associated with persistent fibrosis.

CONCLUSIONS

In bariatric patients before surgery, higher age, alanine transaminase, and total calorie and lower copper intakes were independent risk factors associated with liver fibrosis. These relationships were no longer observed after RYGB, likely due to the effect of surgery on weight and similar postsurgery diet among patients.

Apigenin Alleviated High-Fat-Diet-Induced Hepatic Pyroptosis by Mitophagy-ROS-CTSB-NLRP3 Pathway in Mice and AML12 Cells

Apigenin is considered the most-known natural flavonoid and is abundant in a wide variety of fruits and vegetables. A high fat diet (HFD) can induce liver injury and hepatocyte death in multiple ways. Pyroptosis is an innovative type of programmed cell death. Moreover, excessive pyroptosis of hepatocytes leads to liver injury. We used HFD to induce liver cell pyroptosis in C57BL/6J mice in this work. After gavage of apigenin, apigenin can significantly reduce the level of lactate dehydrogenase (LDH) in liver tissue ignited by HFD and reduce the levels of NLRP3 (NOD-like receptor family pyrin domain containing 3), the N-terminal domain of GSDMD (GSDMD-N), cleaved-caspase 1, cathepsin B (CTSB), interleukin-1β (IL-1β) and interleukin-18 (IL-18) protein expression and the colocalization of NLRP3 and CTSB and increase the level of lysosomal associated membrane protein-1 (LAMP-1) protein expression, thus alleviating cell pyroptosis. In a further in vitro mechanism study, we find that palmitic acid (PA) can induce pyroptosis in AML12 cells. After adding apigenin, apigenin can clear the damaged mitochondria through mitophagy and reduce the generation of intracellular reactive oxygen species (ROS), thus alleviating CTSB release caused by lysosomal membrane permeabilization (LMP), reducing the LDH release caused by PA and reducing the levels of NLRP3, GSDMD-N, cleaved-caspase 1, CTSB, IL-1β, and IL-18 protein expression. By adding the mitophagy inhibitor cyclosporin A (CsA), LC3-siRNA, the CTSB inhibitor CA-074 methyl ester (CA-074 Me), and the NLRP3 inhibitor MCC950, the aforementioned results were further confirmed. Therefore, our results show that HFD-fed and PA can damage mitochondria, promote the production of intracellular ROS, enhance the lysosomal membrane permeabilization (LMP), and cause the leakage of CTSB, thus activating the NLRP3 inflammatory body and inducing pyroptosis in C57BL/6J mice and AML12 cells, while apigenin alleviates this phenomenon through the mitophagy-ROS-CTSB-NLRP3 pathway.

The Associations between Multiple Essential Metal(loid)s and Gut Microbiota in Chinese Community-Dwelling Older Adults

Several experimental studies have suggested that individual essential metal(loid)s (EMs) could regulate the gut microbiota. However, human studies assessing the associations between EMs and gut microbiota are limited. This study aimed to examine the associations of individual and multiple EMs with the compositions of the gut microbiota in older adults. A total of 270 Chinese community-dwelling people over 60 years old were included in this study. Urinary concentrations of selected EMs, including vanadium (V), cobalt (Co), selenium (Se), strontium (Sr), magnesium (Mg), calcium (Ca), and molybdenum (Mo), were examined by inductively coupled plasma mass spectrometry. The gut microbiome was assessed using the 16S rRNA gene sequencing analysis. The zero-inflated probabilistic principal components analysis PCA (ZIPPCA) model was performed to denoise substantial noise in microbiome data. Linear regression and the Bayesian Kernel Machine Regression (BKMR) models were utilized to determine the associations between urine EMs and gut microbiota. No significant association between urine EMs and gut microbiota was found in the total sample, whereas some significant associations were found in subgroup analyses: Co was negatively associated with the microbial Shannon (β = -0.072, p < 0.05) and the inverse-Simpson (β = -0.045, p < 0.05) indices among urban older adults; Ca (R² = 0.035) and Sr (R² = 0.023) exhibited significant associations with the altercations of beta diversity in females, while V (R² = 0.095) showed a significant association with altercations of beta diversity in those who often drank. Furthermore, the associations between partial EMs and specific bacterial taxa were also found: the negative and linear associations of Mo with Tenericutes, Sr with Bacteroidales, and Ca with Enterobacteriaceae and Lachnospiraceae, and a positive and linear association of Sr with Bifidobacteriales were found. Our findings suggested that EMs may play an important role in maintaining the steady status of gut microbiota. Prospective studies are needed to replicate these findings.

Inferring Bacterial Community Interactions and Functionalities Associated with Osteopenia and Osteoporosis in Taiwanese Postmenopausal Women

Growing evidence suggests that the gut microbiota and their metabolites are associated with bone homeostasis and fragility. However, this association is limited to microbial taxonomic differences. This study aimed to explore whether gut bacterial community associations, composition, and functions are associated with osteopenia and osteoporosis. We compared the gut bacterial community composition and interactions of healthy postmenopausal women with normal bone density (n = 8) with those of postmenopausal women with osteopenia (n = 18) and osteoporosis (n = 21) through 16S rRNA sequencing coupled with network biology and statistical analyses. The results of this study showed reduced alpha diversity in patients with osteoporosis, followed by that in patients with osteopenia, then in healthy controls. Taxonomic analysis revealed that significantly enriched bacterial genera with higher abundance was observed in patients with osteoporosis and osteopenia than in healthy subjects. Additionally, a co-occurrence network revealed that, compared to healthy controls, bacterial interactions were higher in patients with osteoporosis, followed by those with osteopenia. Further, NetShift analysis showed that a higher number of bacteria drove changes in the microbial community structure of patients with osteoporosis than osteopenia. Correlation analysis revealed that most of these driver bacteria had a significant positive relationship with several significant metabolic pathways. Further, ordination analysis revealed that height and T-score were the primary variables influencing the gut microbial community structure. Taken together, this study evaluated that microbial community interaction is more important than the taxonomic differences in knowing the critical role of gut microbiota in postmenopausal women associated with osteopenia and osteoporosis. Additionally, the significantly enriched bacteria and functional pathways might be potential biomarkers for the prognosis and treatment of postmenopausal women with osteopenia and osteoporosis.

Liver Protein Expression in NASH Mice on a High-Fat Diet: Response to Multi-Mineral Intervention

Male MS-NASH mice were maintained on a high-fat diet for 16 weeks with and without red algae-derived minerals. Obeticholic acid (OCA) was used as a comparator in the same strain and diet. C57BL/6 mice maintained on a standard (low-fat) rodent chow diet were used as a control. At the end of the in-life portion of the study, body weight, liver weight, liver enzyme levels and liver histology were assessed. Samples obtained from individual livers were subjected to Tandem Mass Tag labeling / mass spectroscopy for protein profile determination. As compared to mice maintained on the low-fat diet, all high-fat-fed mice had increased whole-body and liver weight, increased liver enzyme (aminotransferases) levels and widespread steatosis / ballooning hepatocyte degeneration. Histological evidence for liver inflammation and collagen deposition was also present, but changes were to a lesser extent. A moderate reduction in ballooning degeneration and collagen deposition was observed with mineral supplementation. Control mice on the high-fat diet alone demonstrated multiple protein changes associated with dysregulated fat and carbohydrate metabolism, lipotoxicity and oxidative stress. Cholesterol metabolism and bile acid formation were especially sensitive to diet. In mice receiving multi-mineral supplementation along with the high-fat diet, there was reduced liver toxicity as evidenced by a decrease in levels of several cytochrome P450 enzymes and other oxidant-generating moieties. Additionally, elevated expression of several keratins was also detected in mineral-supplemented mice. The protein changes observed with mineral supplementation were not seen with OCA. Our previous studies have shown that mice maintained on a high-fat diet for up to 18 months develop end-stage liver injury including hepatocellular carcinoma. Mineral-supplemented mice were substantially protected against tumor formation and other end-state consequences of high-fat feeding. The present study identifies early (16-week) protein changes occurring in the livers of the high-fat diet-fed mice, and how the expression of these proteins is influenced by mineral supplementation. These findings help elucidate early protein changes that contribute to end-stage liver injury and potential mechanisms by which dietary minerals may mitigate such damage.

The association between Dietary Diversity Score and odds of nonalcoholic fatty liver disease: a case-control study

OBJECTIVE

There is no previous study that investigated the association between Dietary Diversity Score (DSS) and odds of nonalcoholic fatty liver disease (NAFLD). The present study aimed to examine the association between DDS and its components and NAFLD among Iranian adults.

METHODS

In the case-control study, we enrolled 121 newly diagnosed cases of NAFLD and 122 with age, BMI and sex-matched controls. All NAFLD patients were diagnosed through ultrasonography methods by gastroenterologists. Anthropometric parameters of participants including weight, height, hip circumference and waist circumference were measured. A validated 147-item semi-quantitative food frequency questionnaire was applied to assess the usual dietary intakes of participants. Binary logistic regression was conducted to estimate the risk of NAFLD in relation to DDS and its components, including refined grains, vegetables, fruits, dairy and meats.

RESULTS

The mean age of study participants was 42.7 years of them 53.1% were male. Higher adherence to DDS [odds ratio (OR) = 0.48; 95% confidence interval (CI), 0.25-0.95] and vegetable group (OR = 0.34; 95% CI, 0.16-0.71) were remarkably associated with lower risk of NAFLD, after adjusting for several confounders including age, BMI, physical activity, energy intake, job, education, and antihypertensive drugs usage. Contrastingly, greater adherence to the refined grain (OR = 3.36; 95% CI, 1.44-7.87) and meat group (OR = 3.27; 95% CI, 1.25-6.90) was significantly associated with increased risk of NAFLD.

CONCLUSION

High DDS is inversely correlated with the risk of NAFLD. Hence, increasing the diversity score of diet by emphasizing the higher diversity scores for vegetables and less for meat and refined grains may be profitable for the management of NAFLD.

Gut Microbiota and Bone Diseases: A Growing Partnership

Gut microbiota is key to human health and disease. Convincing studies have demonstrated that dysbiosis in the commensal gut microbiota is associated with intestinal and extra-intestinal diseases. Recent explorations have significantly contributed to the understanding of the relationship between gut microbiota and bone diseases (osteoporosis, osteoarthritis, rheumatoid arthritis, and bone cancer). Gut microbiota and its metabolites may become associated with the development and progression of bone disorders owing to their critical role in nutrient absorption, immunomodulation, and the gut–brain–bone axis (regulation hormones). In this work, we review the recent developments addressing the effect of gut microbiota modulation on skeletal diseases and explore a feasible preventive approach and therapy for bone diseases.

Let-7i-5p Mediates the Therapeutic Effects of Exosomes from Human Placenta Choriodecidual Membrane-Derived Mesenchymal Stem Cells on Mitigating Endotoxin-Induced Mortality and Liver Injury in High-Fat Diet-Induced Obese Mice

Obesity complicates sepsis and increases the mortality of sepsis. We examined the effects of exosomes (from human placenta choriodecidual membrane-derived mesenchymal stem cells, pcMSCs) on preventing sepsis in obesity and the mitigating role of hsa-let-7i-5p microRNA. Obese mice (adult male C57BL/6J mice fed a high-fat diet for 12 weeks) received normal saline (HFD), endotoxin (10 mg/kg, intraperitoneal (ip); HFDLPS), endotoxin with exosomes (1 × 10⁸ particles/mouse, ip; HLE), or endotoxin with let-7i-5p microRNA inhibitor-pretreated exosomes (1 × 10⁸ particles/mouse, ip; HLEi). Our data demonstrated that the 48-h survival rate in the HLE (100%) group was significantly higher than in the HFDLPS (50%) and HLEi (58.3%) groups (both p < 0.05). In the surviving mice, by contrast, levels of liver injury (injury score, plasma aspartate transaminase and alanine transaminase concentrations, tissue water content, and leukocyte infiltration in liver tissues; all p < 0.05), inflammation (nuclear factor-κB activation, hypoxia-inducible factor-1α activation, macrophage activation, and concentrations of tumor necrosis factor-α, interleukin-6, and leptin in liver tissues; all p < 0.05), and oxidation (malondialdehyde in liver tissues, with p < 0.001) in the HLE group were significantly lower than in the HFDLPS group. Levels of mitochondrial injury/dysfunction and apoptosis in liver tissues in the HLE group were also significantly lower than in the HFDLPS group (all p < 0.05). Inhibition of let-7i-5p microRNA offset the effects of the exosomes, with most of the aforementioned measurements in the HLEi group being significantly higher than in the HLE group (all p < 0.05). In conclusion, exosomes mitigated endotoxin-induced mortality and liver injury in obese mice, and these effects were mediated by let-7i-5p microRNA.

Ru360 and Mitoxantrone inhibit MCU channel to relieve liver steatosis induced by high-fat diet

BACKGROUND AND PURPOSE

Nonalcoholic fatty liver disease (NAFLD) affects over 25% of the general population and lacks an effective treatment. Recent evidence implicates disrupted mitochondrial calcium homeostasis in the pathogenesis of hepatic steatosis.

EXPERIMENTAL APPROACH

In this study, mitochondrial calcium uniporter (MCU) was inhibited through classical genetic approaches, viral vectors or small molecule inhibitors in vivo to study its role in hepatic steatosis induced by HFD. In vitro, MCU was overexpressed or inhibited to change mitochondrial calcium homeostasis; endoplasmic reticulum-mitochondrial linker was adopted to increase mitochondria-associated membranes (MAM); and MICU1-EF hand mutant was used to decrease the sensitivity of mitochondrial calcium uptake 1 (MICU1) to calcium and block MCU channel.

KEY RESULTS

Here we found that inhibition of liver MCU by AAV virus and classical genetic approaches can alleviate HFD-induced liver steatosis. MCU regulates mitochondrial calcium homeostasis and affects lipid accumulation in liver cells. In addition, a HFD in mice enlarged the MAM. The high calcium environment produced by MAM invalidated the function of MICU1 and led to persistent open of MCU channels. Therefore, it caused mitochondrial calcium overload and liver fat deposition. Inhibition of MAM and MCU alleviated HFD-induced hepatic steatosis. MCU inhibitors (Ru360 and mitoxantrone) can block MCU channels and reduce mitochondrial calcium levels. Intraperitoneal injection of MCU inhibitors (0.01 μM/kg bodyweight) can alleviate HFD-induced hepatic steatosis.

CONCLUSION AND IMPLICATIONS

These findings provide molecular insights into the way HFD disrupts mitochondrial calcium homeostasis and identified MCU as a promising drug target for the treatment of hepatic steatosis.

The Nasopharyngeal, Ruminal, and Vaginal Microbiota and the Core Taxa Shared across These Microbiomes in Virgin Yearling Heifers Exposed to Divergent In Utero Nutrition during Their First Trimester of Gestation and in Pregnant Beef Heifers in Response to Mineral Supplementation

In the present study, we evaluated whether the nasopharyngeal, ruminal, and vaginal microbiota would diverge (1) in virgin yearling beef heifers (9 months old) due to the maternal restricted gain during the first trimester of gestation; and (2) in pregnant beef heifers in response to the vitamin and mineral (VTM) supplementation during the first 6 months of pregnancy. As a secondary objective, using the microbiota data obtained from these two cohorts of beef heifers managed at the same location and sampled at the same time, we performed a holistic assessment of the microbial ecology residing within the respiratory, gastrointestinal, and reproductive tract of cattle. Our 16S rRNA gene sequencing results revealed that both α and β-diversity of the nasopharyngeal, ruminal and vaginal microbiota did not differ between virgin heifers raised from dams exposed to either a low gain (targeted average daily gain of 0.28 kg/d, n = 22) or a moderate gain treatment (0.79 kg/d, n = 23) during the first 84 days of gestation. Only in the vaginal microbiota were there relatively abundant genera that were affected by maternal rate of gain during early gestation. Whilst there was no significant difference in community structure and diversity in any of the three microbiota between pregnant heifers received no VTM (n = 15) and VTM supplemented (n = 17) diets, the VTM supplementation resulted in subtle compositional alterations in the nasopharyngeal and ruminal microbiota. Although the nasopharyngeal, ruminal, and vaginal microbiota were clearly distinct, a total of 41 OTUs, including methanogenic archaea, were identified as core taxa shared across the respiratory, gastrointestinal, and reproductive tracts of both virgin and pregnant heifers.

Calcium supplementation relieves high-fat diet-induced liver steatosis by reducing energy metabolism and promoting lipolysis

Nonalcoholic fatty liver disease (NAFLD) is a chronic disease affecting the health of many people worldwide. Previous studies have shown that dietary calcium supplementation may alleviate NAFLD, but the underlying mechanism is not clear. In this study investigating the effect of calcium on hepatic lipid metabolism, 8-week-old male C57BL/6J mice were divided into four groups (n = 6): (1) mice given a normal chow containing 0.5% calcium (CN0.5), (2) mice given a normal chow containing 1.2% calcium (CN1.2), (3) mice given a high-fat diet (HFD) containing 0.5% calcium (HFD0.5), and (4) mice fed a HFD containing 1.2% calcium (HFD1.2). To understand the underlying mechanism, cells were treated with oleic acid and palmitic acid to mimic the HFD conditions in vitro. The results showed that calcium alleviated the increase in triglyceride accumulation induced by oleic acid and/or palmitic acid in HepG2, AML12, and primary hepatocyte cells. Our data demonstrated that calcium supplementation alleviated HFD-induced hepatic steatosis through increased liver lipase activity, proving calcium is involved in the regulation of hepatic lipid metabolism. Moreover, calcium also increased the level of glycogen in the liver, and at the same time had the effect of reducing glycolysis and promoting glucose absorption. Calcium addition increased calcium levels in the mitochondria and cytoplasm. Taken together, we concluded that calcium supplementation could relieve HFD-induced hepatic steatosis by changing energy metabolism and lipase activity.

The Gut Microbiome: a New Frontier in Musculoskeletal Research

PURPOSE OF THE REVIEW

The human gut harbors a complex community of microbes that influence many processes regulating musculoskeletal development and homeostasis. This review gives an update on the current knowledge surrounding the impact of the gut microbiota on musculoskeletal health, with an emphasis on research conducted over the last three years.

RECENT FINDINGS

The gut microbiota and their metabolites are associated with sarcopenia, osteoporosis, osteoarthritis, and rheumatoid arthritis. The field is moving fast from describing simple correlations to pursue establishing causation through clinical trials. The gut microbiota and their microbial-synthesized metabolites hold promise for offering new potential alternatives for the prevention and treatment of musculoskeletal diseases given its malleability and response to environmental stimuli.

Relationship between gut microbiota and host-metabolism: Emphasis on hormones related to reproductive function

It has been well recognized that interactions between the gut microbiota and host-metabolism have a proven effect on health. The gut lumen is known for harboring different bacterial communities. Microbial by-products and structural components, which are derived through the gut microbiota, generate a signaling response to maintain homeostasis. Gut microbiota is not only involved in metabolic disorders, but also participates in the regulation of reproductive hormonal function. Bacterial phyla, which are localized in the gut, allow for the metabolization of steroid hormones through the stimulation of different enzymes. Reproductive hormones such as progesterone, estrogen and testosterone play a pivotal role in the successful completion of reproductive events. Disruption in this mechanism may lead to reproductive disorders. Environmental bacteria can affect the metabolism, and degrade steroid hormones and their relevant compounds. This behavior of the bacteria can safely be implemented to eliminate steroidal compounds from a polluted environment. In this review, we summarize the metabolism of steroid hormones on the regulation of gut microbiota and vice-versa, and also examined the significant influence this process has on various events of reproductive function. Altogether, the evidence suggests that steroid hormones and gut microbiota exert a central role in the modification of host bacterial action and impact the reproductive efficiency of animals and humans.

Experimental rat model for acute tubular injury induced by high water hardness and high water fluoride: efficacy of primary preventive intervention by distilled water administration

Background

High water hardness associated with high water fluoride and the geographical distribution of Chronic Kidney Disease of unknown etiology (CKDu) in Sri Lanka are well correlated. We undertook this study to observe the effects of high water hardness with high fluoride on kidney and liver in rats and efficacy of distilled water in reducing the effects.

Methods

Test water sample with high water hardness and high fluoride was collected from Mihinthale region and normal water samples were collected from Kandy region. Twenty-four rats were randomly divided into 8 groups and water samples were introduced as follows as daily water supply. Four groups received normal water for 60 (N1) and 90 (N2) days and test water for 60 (T1) and 90 (T2) days. Other four groups received normal (N3) and test (T3) water for 60 days and followed by distilled water for additional 60 days and normal (N4) and test (T4) water for 90 days followed by distilled water for another 90 days. The rats were sacrificed following treatment. Serum samples were subjected to biochemical tests; serum creatinine, urea, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP) and elemental analysis. Histopathological examinations were carried out using kidney and liver samples.

Results

Test water treated groups were associated with acute tubular injury with loss of brush border and test water followed with distilled water treated groups maintained a better morphology with minimal loss of brush border. Serum creatinine levels in T1 and T2 groups and urea level in T2 group were significantly (p < 0.05) increased compared to control groups. After administration of distilled water, both parameters were significantly reduced in T4 group (p < 0.05) compared to T2. Serum AST activity was increased in T4 group (p < 0.05) compared to control group with no histopathological changes in liver tissues. The serum sodium levels were found to be much higher compared to the other electrolytes in test groups.

Conclusion

Hard water with high fluoride content resulted in acute tubular injury with a significant increase in serum levels of creatinine, urea and AST activity. These alterations were minimized by administering distilled water.

Molecular Mechanisms: Connections between Nonalcoholic Fatty Liver Disease, Steatohepatitis and Hepatocellular Carcinoma

Nonalcoholic fatty liver disease (NAFLD), including nonalcoholic steatohepatitis (NASH), causes hepatic fibrosis, cirrhosis and hepatocellular carcinoma (HCC). The patatin-like phospholipase-3 (PNPLA3) I148M sequence variant is one of the strongest genetic determinants of NAFLD/NASH. PNPLA3 is an independent risk factor for HCC among patients with NASH. The obesity epidemic is closely associated with the rising prevalence and severity of NAFLD/NASH. Furthermore, metabolic syndrome exacerbates the course of NAFLD/NASH. These factors are able to induce apoptosis and activate immune and inflammatory pathways, resulting in the development of hepatic fibrosis and NASH, leading to progression toward HCC. Small intestinal bacterial overgrowth (SIBO), destruction of the intestinal mucosa barrier function and a high-fat diet all seem to exacerbate the development of hepatic fibrosis and NASH, leading to HCC in patients with NAFLD/NASH. Thus, the intestinal microbiota may play a role in the development of NAFLD/NASH. In this review, we describe recent advances in our knowledge of the molecular mechanisms contributing to the development of hepatic fibrosis and HCC in patients with NAFLD/NASH.

Role of Dietary Nutrients in the Modulation of Gut Microbiota: A Narrative Review

Understanding how dietary nutrients modulate the gut microbiome is of great interest for the development of food products and eating patterns for combatting the global burden of non-communicable diseases. In this narrative review we assess scientific studies published from 2005 to 2019 that evaluated the effect of micro- and macro-nutrients on the composition of the gut microbiome using in vitro and in vivo models, and human clinical trials. The clinical evidence for micronutrients is less clear and generally lacking. However, preclinical evidence suggests that red wine- and tea-derived polyphenols and vitamin D can modulate potentially beneficial bacteria. Current research shows consistent clinical evidence that dietary fibers, including arabinoxylans, galacto-oligosaccharides, inulin, and oligofructose, promote a range of beneficial bacteria and suppress potentially detrimental species. The preclinical evidence suggests that both the quantity and type of fat modulate both beneficial and potentially detrimental microbes, as well as the Firmicutes/Bacteroides ratio in the gut. Clinical and preclinical studies suggest that the type and amount of proteins in the diet has substantial and differential effects on the gut microbiota. Further clinical investigation of the effect of micronutrients and macronutrients on the microbiome and metabolome is warranted, along with understanding how this influences host health.

Changes of gut microbiota during silybin-mediated treatment of high-fat diet-induced non-alcoholic fatty liver disease in mice

AIM

Gut microbiota are involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Silybin (Sil), a naturally occurring hepatoprotective agent, is widely used for treating NAFLD. Whether Sil affects gut microbiota during its actions in treating NAFLD is unknown. We aimed to examine the effect of Sil on intestinal flora dysbiosis induced by a high-fat diet (HFD).

METHODS

After 10 weeks of feeding normal chow diet or HFD, mice were given a daily gavage for 8 weeks. Cecal contents were harvested for study of short-chain fatty acids, bile acids, and gut microbiota alteration.

RESULTS

Sil showed protective effects against dietary-induced obesity and liver steatosis; accordingly, gut microbiota composition changed. At the phylum level, compared with the HFD group, mice in the Sil-treated group had significantly lower levels of Firmicutes, and the ratio of Firmicutes-to-Bacteroidetes was lower (P < 0.05). At the genus level, the Sil-treated group have significantly lower levels of Lachnoclostridium, Lachnospiraceae_UCG-006, and Mollicutes_RF9, which were reported to be potentially related to diet-induced obesity, and increased levels of Blautia (P < 0.05), Akkermansia (P < 0.05), and Bacteroides (P < 0.05), which are known to have a beneficial effect on improving NAFLD. Sil also showed an inhibitory effect on well-known beneficial bacteria, such as Alloprevotella and Lactobacillus. Furthermore, the production of acetate, propionate, and butyrate increased, whereas the generation of formate and conversion of cytotoxic secondary metabolites (lithocholic acid and deoxy-cholic acid) decreased in mice treated with Sil.

CONCLUSIONS

Sil might have beneficial effects on ameliorating NAFLD and mediating HFD-induced change of gut microbiota composition, followed by major changes in secondary metabolites, such as short-chain fatty acids and bile acids.

A Calcium-Rich Multimineral Intervention to Modulate Colonic Microbial Communities and Metabolomic Profiles in Humans: Results from a 90-Day Trial

Aquamin is a calcium-, magnesium-, and multiple trace element-rich natural product with colon polyp prevention efficacy based on preclinical studies. The goal of this study was to determine the effects of Aquamin on colonic microbial community and attendant metabolomic profile. Thirty healthy human participants were enrolled in a 90-day trial in which Aquamin (delivering 800 mg of calcium per day) was compared with calcium alone or placebo. Before and after the intervention, colonic biopsies and stool specimens were obtained. All 30 participants completed the study without serious adverse event or change in liver and renal function markers. Compared with pretreatment values, intervention with Aquamin led to a reduction in total bacterial DNA (P = 0.0001) and a shift in the microbial community measured by thetaYC (θYC; P = 0.0087). Treatment with calcium also produced a decline in total bacteria, but smaller than seen with Aquamin, whereas no reduction was observed with placebo in the colon. In parallel with microbial changes, a reduction in total bile acid levels (P = 0.0375) and a slight increase in the level of the short-chain fatty acid (SCFA) acetate in stool specimens (P < 0.0001) from Aquamin-treated participants were noted. No change in bile acids or SCFAs was observed with calcium or placebo. We conclude that Aquamin is safe and tolerable in healthy human participants and may produce beneficial alterations in the colonic microbial community and the attendant metabolomic profile. Because the number of participants was small, the findings should be considered preliminary.

Compositional alterations of gut microbiota in children with primary nephrotic syndrome after initial therapy

Background

Primary nephrotic syndrome (PNS) is a common glomerular disease in children. T cell dysfunction plays a crucial role in the pathogenesis of PNS. Moreover, dysbiosis of gut microbiota contributes to immunological disorders. Whether the initial therapy of PNS affects gut microbiota remains an important question. Our study investigated compositional changes of gut microbiota after initial therapy.

Methods

Fecal samples of 20 children with PNS were collected before and after 4-week initial therapy. Total bacteria DNA were extracted and the V3-V4 regions of bacteria 16S ribosomal RNA gene were sequenced. The composition of gut microbiota before and after initial therapy was analyzed by bioinformatics methods. The function of altered gut microbiota was predicted with PICRUSt method.

Results

The richness and diversity of gut microbiota were similar before and after 4-week initial therapy. Gut microbiota at the phylum level was dominated by four phyla including Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria, but the increased relative abundance after initial therapy was found in Deinococcus-Thermus and Acidobacteria. At the genus level, the increased abundance of gut microbiota after initial therapy was observed in short chain fat acids (SCFA)-producing bacteria including Romboutsia, Stomatobaculum and Cloacibacillus (p < 0.05). Moreover, the predicted functional profile of gut microbiota showed that selenocompound metabolism, isoflavonoid biosynthesis and phosphatidylinositol signaling system weakened after initial therapy of PNS.

Conclusions

Initial therapy of PNS increased SCFA-producing gut microbiota, but might diminish selenocompound metabolism, isoflavonoid biosynthesis and phosphatidylinositol signaling system in children.

Abnormality in Maternal Dietary Calcium Intake During Pregnancy and Lactation Promotes Body Weight Gain by Affecting the Gut Microbiota in Mouse Offspring

SCOPE

To investigate the effects of calcium status in early life on adult body weight and the underlying mechanisms involved in gut microbiota and related lipid metabolism.

METHODS AND RESULTS

Three to four-week-old C57BL/6J female mice were fed diets with normal, insufficient, and excessive calcium respectively throughout pregnancy and lactation. The weaning male pups were fed with a high-fat diet for 16 weeks, with a normal-fat diet to the normal calcium group as control. The offspring fecal microbiota was analyzed by 16S rRNA high-throughput sequencing, and mRNA expressions of genes were determined by the real-time RT-PCR. Maternal insufficient or excessive calcium intake exacerbated offspring obesity, with expressional changes in the Fasn, Acc1, LPL, Fiaf, and PPAR-α genes in the liver or fat. The dysbiosis in gut microbiota in obese offspring was exacerbated by maternal imbalanced calcium intake, with increased Firmicutes and decreased Bacteroidetes in calcium insufficiency, and decreased Verrucomicrobia in calcium excess. Several genera, including Bacteroides, were reduced, and Lachnospiraceae and Lactobacillus were increased by maternal insufficient or excessive calcium intake.

CONCLUSION

Imbalance in maternal calcium intake promotes body weight gain in offspring, which may be mediated by calcium's modulation on the gut microbiota and lipid metabolism.

Qualitative and Quantitative Evaluation of Dietary Intake in Patients with Non-Alcoholic Steatohepatitis

There are very few reports about the intake of nutrients for the development or progression of non-alcoholic steatohepatitis (NASH). The aim of this study was to identify the dietary habits and the nutrient intake in patients with NASH, in comparison to chronic hepatitis C (HCV)-related patients. We prospectively evaluated the intake of macronutrients and micronutrients in 124 NAFLD and 162 HCV patients, compared to 2326 subjects as a control group. We noticed major differences in macro- and micronutrients intakes in NASH and HCV patients compared to controls. Proteins, carbohydrate (glucose, fructose, sucrose, maltose and amide), saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), folic acid, vitamin A and C (p < 0.0001), and thiamine (p < 0.0003) ingestion was found to be higher in patients with NASH, while total lipids, polyunsaturated fatty acid (PUFA), riboflavin and vitamin B6 daily intake were lower compared to controls (p < 0.0001). Similarly, NASH patients had significantly reduced carbohydrate intake (p < 0.0001) and an increased intake of calcium (p < 0.0001) compared to HCV positive patients. Finally, we showed in NASH males an increase in the intake of SFA, PUFA, soluble carbohydrates (p < 0.0001) and a decrease in the amount of fiber (p < 0.0001) compared to control males. In NASH female population, we showed an increase of daily total calories, SFA, MUFA, soluble carbohydrates, starch and vitamin D ingested (p < 0.0001) with a reduction of fibers and calcium (p < 0.0001) compared to control females. This study showed how NASH patients’ diets, in both male and females, is affected by a profound alteration in macro- and micronutrients intake.

Correction: Calcium Reduces Liver Injury in Mice on a High-Fat Diet: Alterations in Microbial and Bile Acid Profiles

[This corrects the article DOI: 10.1371/journal.pone.0166178.].