Dietary antioxidant lack, impaired hepatic glutathione reserve, and cholesterol gallstones

Relationship between Abnormal Lipid Metabolism and Gallstone Formation

Cholelithiasis is a common biliary system disease with a high incidence worldwide. Abnormal lipid metabolism has been shown to play a key role in the mechanism of gallstones. Therefore, recent research literature on the genes, proteins, and molecular substances involved in lipid metabolism during the pathogenesis of gallstones has been conducted. This study aimed to determine the role of lipid metabolism in the pathogenesis of gallstones and provide insights for future studies using previous research in genomics, metabolomics, transcriptomics, and other fields.

Attenuation of Experimental Cholesterol Gallstone Formation by Manganese Chloride in Mice: Role of NF-κβ Pathways

Manganese (Mn), a trace element, has been documented to exert an important role in the metabolism of cholesterol. Cholesterol gallstone (CG) pathogenesis is directly linked to biliary cholesterol imbalance which could be due to diabetes complications or mismanagement. NF-κβ pathway, an inflammatory regulator, has been implicated in metabolic disease especially in the context of diabetes and gallstone formation. However, the management of cholesterol gallstones due to diabetes with trace elements is vague. This study investigates the probable role of manganese during CG formation due to diabetes complications. Eighty female Swiss mice were grouped: I (control), II (untreated CG), III and IV (normal mice treated 0.37 mg/kg and 0.74 mg/kg Mn, respectively), V and VI (CG treated 0.37 mg/kg and 0.74 mg/kg Mn, respectively), and VII and VIII (CG treated 75 mg/7 kg and 350 mg/kg aspirin, respectively). Experimental CG was induced with cholesterol-rich diets after alloxan-induced diabetes. On sacrifice, blood collected was evaluated for complete hematological analysis and biochemistry while the excised liver was assayed for biochemical variables. Results were subjected to one-way ANOVA values were expressed as Mean ± SEM and significant at p ≤ 0.05. Manganese treatment significantly increased packed cell volume, RBC count, and hemoglobin with decreased platelet and leukocyte counts, liver enzymes (AST, ALT, and ALP), BUN, and creatinine levels in CG groups compared with untreated CG. Blood glucose, plasma low-density lipoproteins, and liver malodialdehyde levels were significantly reduced while liver nitric-oxide, sulfhydryl, and glutathione levels increased significantly in manganese-treated groups compared with untreated CG. Manganese significantly increased fecal iron contents in normal mice by the 2nd week. Hepatocytes and gallbladder histology appear normal in manganese-treated groups. Liver NF-Kβ immunoreactivity was downregulated in manganese-treated CG groups. Manganese attenuated experimental hyperglycemia-induced cholesterol gallstone by ameliorating liver oxidative stress and NF-Kβ inflammatory pathway.

Characterizing the relationships between dietary indices, gallstone prevalence and the need for gallbladder surgery in the general US population

Background

The dietary inflammatory index (DII) and composite dietary antioxidant index (CDAI) were developed as tools for use when seeking to assess the potential inflammatory and antioxidant activity of a given diet, respectively. The associations between these indices and gallstone incidence remain largely unexplored.

Objective

The present study sought to clarify how both the DII and the CDAI are related to gallstone incidence and age at first gallbladder surgery among adults in the USA.

Methods

Cross-sectional data from the 2017-2020 cycles of the National Health and Nutrition Examination Survey (NHANES) pertaining to 12,426 individuals were used to conduct the present study. Data from 2 days with 24-h dietary recall were employed when calculating DII and CDAI scores. Relationships between dietary indices and the incidence of gallstones were assessed through logistic regression analyses, while linear regression analyses were employed to characterize how these indices are associated with the age at first gallbladder surgery.

Results

Higher DII scores and lower CDAI scores, which, respectively, denote diets with greater inflammatory potential and reduced antioxidant potential, were found to be associated with higher gallstone incidence even following adjustment for potential confounding factors. Smooth curve fitting suggested that the association between DII and gallstones was nearly linear, whereas that between CDAI and gallstone incidence was nonlinear. Higher DII values were also related to first gallbladder surgery at an earlier age (β = -0.64, 95% CI: -1.26, -0.02).

Conclusion

These results emphasize the benefits of anti-inflammatory diets rich in antioxidants, which may help reduce gallstone incidence among adults in the USA. Higher DII scores may also predict the need for gallbladder surgery at a younger age.

Insight into the mechanism of gallstone disease by proteomic and metaproteomic characterization of human bile

Introduction

Cholesterol gallstone disease is a prevalent condition that has a significant economic impact. However, the role of the bile microbiome in its development and the host's responses to it remain poorly understood.

Methods

In this study, we conducted a comprehensive analysis of microbial and human bile proteins in 40 individuals with either gallstone disease or gallbladder polyps. We employed a combined proteomic and metaproteomic approach, as well as meta-taxonomic analysis, functional pathway enrichment, and Western blot analyses.

Results

Our metaproteomic analysis, utilizing the lowest common ancestor algorithm, identified 158 microbial taxa in the bile samples. We discovered microbial taxa that may contribute to gallstone formation, including β-glucuronidase-producing bacteria such as Streptococcus, Staphylococcus, and Clostridium, as well as those involved in biofilm formation like Helicobacter, Cyanobacteria, Pseudomonas, Escherichia coli, and Clostridium. Furthermore, we identified 2,749 human proteins and 87 microbial proteins with a protein false discovery rate (FDR) of 1% and at least 2 distinct peptides. Among these proteins, we found microbial proteins crucial to biofilm formation, such as QDR3, ompA, ndk, pstS, nanA, pfIB, and dnaK. Notably, QDR3 showed a gradual upregulation from chronic to acute cholesterol gallstone disease when compared to polyp samples. Additionally, we discovered other microbial proteins that enhance bacterial virulence and gallstone formation by counteracting host oxidative stress, including sodB, katG, rbr, htrA, and ahpC. We also identified microbial proteins like lepA, rtxA, pckA, tuf, and tpiA that are linked to bacterial virulence and potential gallstone formation, with lepA being upregulated in gallstone bile compared to polyp bile. Furthermore, our analysis of the host proteome in gallstone bile revealed enhanced inflammatory molecular profiles, including innate immune molecules against microbial infections. Gallstone bile exhibited overrepresented pathways related to blood coagulation, folate metabolism, and the IL-17 pathway. However, we observed suppressed metabolic activities, particularly catabolic metabolism and transport activities, in gallstone bile compared to polyp bile. Notably, acute cholelithiasis bile demonstrated significantly impaired metabolic activities compared to chronic cholelithiasis bile.

Conclusion

Our study provides a comprehensive metaproteomic analysis of bile samples related to gallstone disease, offering new insights into the microbiome-host interaction and gallstone formation mechanism.

Glutaredoxin 1 regulates cholesterol metabolism and gallstone formation by influencing protein S-glutathionylation

OBJECTIVE

Cholesterol gallstone disease (CGD) is closely related to cholesterol metabolic disorder. Glutaredoxin-1 (Glrx1) and Glrx1-related protein S-glutathionylation are increasingly being observed to drive various physiological and pathological processes, especially in metabolic diseases such as diabetes, obesity and fatty liver. However, Glrx1 has been minimally explored in cholesterol metabolism and gallstone disease.

METHODS

We first investigated whether Glrx1 plays a role in gallstone formation in lithogenic diet-fed mice using immunoblotting and quantitative real-time PCR. Then a whole-body Glrx1-deficient (Glrx1^-/-) mice and hepatic-specific Glrx1-overexpressing (AAV8-TBG-Glrx1) mice were generated, in which we analyzed the effects of Glrx1 on lipid metabolism upon LGD feeding. Quantitative proteomic analysis and immunoprecipitation (IP) of glutathionylated proteins were performed.

RESULTS

We found that protein S-glutathionylation was markedly decreased and the deglutathionylating enzyme Glrx1 was greatly increased in the liver of lithogenic diet-fed mice. Glrx1^-/- mice were protected from gallstone disease induced by a lithogenic diet because their biliary cholesterol and cholesterol saturation index (CSI) were reduced. Conversely, AAV8-TBG-Glrx1 mice showed greater gallstone progression with increased cholesterol secretion and CSI. Further studies showed that Glrx1-overexpressing greatly induced bile acid levels and/or composition to increase intestinal cholesterol absorption by upregulating Cyp8b1. In addition, liquid chromatography-mass spectrometry and IP analysis revealed that Glrx1 also affected the function of asialoglycoprotein receptor 1 (ASGR1) by mediating its deglutathionylation, thereby altering the expression of LXRα and controlling cholesterol secretion.

CONCLUSION

Our findings present novel roles of Glrx1 and Glrx1-regulated protein S-glutathionylation in gallstone formation through the targeting of cholesterol metabolism. Our data advises Glrx1 significantly increased gallstone formation by simultaneously increase bile-acid-dependent cholesterol absorption and ASGR1- LXRα-dependent cholesterol efflux. Our work suggests the potential effects of inhibiting Glrx1 activity to treat cholelithiasis.

Dietary Total Antioxidant Capacity and Risk of Gall Stone: A Case-Control Study

Background

Since the relation between dietary total antioxidant capacity (DTAC) and the occurrence of gallstone disease (GSD) remains unclear, we conducted, for the first time, a case-control study to clarify this association in the Iranian population.

Methods

In the present case-control study, convenience Sampling was performed. A total of 600 participants (300 case and 300 control) were included. Anthropometric, demographic, physical activity, and nutrient intakes data were obtained from each subject. DTAC was calculated using the US Department of Agriculture's database. The odds ratio (OR) and 95% confidence intervals were assessed using unconditional logistic regression.

Results

The participants in the highest quartile of DTAC had a significantly lower OR for gallstone than the lowest quartile, which remained significant after further adjustment for age, sex, and education (model 2: OR, 0.34; 95% CI, 0.16-0.71). In addition, after adjustment for age, sex, education, BMI, physical activity, and energy, the results revealed that participants with the highest quartile of DTAC had 71% lower odds of gallstone than those with the lowest quartile (model 3: OR, 0.29; 95% CI, 0.11-0.78).

Conclusions

The results of the present study demonstrated that the DTAC had an inverse association with GSD incident. However, interventional approaches are needed to confirm the relation between DTAC and GSD prevention.

The Effect of Diet On Gallstones Formation in Turkish Patients: A Case-Control Study

Aim: There are many defined risk factors for the formation of gallstones and nutrition is one of them. We have investigated if there is a relationship between diet and gallstone formation in Turkish gallstone patients. Methods: This prospective case-control study were performed between July 2018- March 2019. A food consumption survey was performed to the gallstone patients and control group. The results of demographic and food consumption data of gallstone patients were compared. Results: There were 110 patients with gallbladder stones and 115 controls with no gallbladder stones. There was no significant difference between the two groups in terms of demographic data; but body mass index was higher and regular physical activity was lower in case group. Although case group eat more eggs than the controls, there were no statistically significant difference. In case group, the consumption of snack and cheese, energy intake, more daily fat consumption, more saturated fatty acids, and cholesterol uptake was higher, whereas red meat consumption was lower. Conclusion: A significant association between the gallstone and the nutrition especially in particular nutritional elements supports the fact that, diet is an important risk factor for gallbladder stone formation. Keywords: gallstones, nutrition, cholesterol, diet

Bile Metabolism and Lithogenesis: An Update

Bile is composed of multiple macromolecules, including bile acids, free cholesterol, phospholipids, bilirubin, and inorganic ions that aid in digestion, nutrient absorption, and disposal of the insoluble products of heme catabolism. The synthesis and release of bile acids is tightly controlled and dependent on feedback mechanisms that regulate enterohepatic circulation. Alterations in bile composition, impaired gallbladder relaxation, and accelerated nucleation are the principal mechanisms leading to biliary stone formation. Various physiologic conditions and disease states alter bile composition and metabolism, thus increasing the risk of developing gallstones.

Association of Circulating Vitamin E (α- and γ-Tocopherol) Levels with Gallstone Disease

In addition to well-established risk factors like older age, female gender, and adiposity, oxidative stress may play a role in the pathophysiology of gallstone disease. Since vitamin E exerts important anti-oxidative functions, we hypothesized that circulating vitamin E levels might be inversely associated with prevalence of gallstone disease. In a cross-sectional study, we measured plasma levels of α- and γ-tocopherol using high performance liquid chromatography in a community-based sample (582 individuals; median age 62 years; 38.5% women). Gallstone disease status was assessed by ultrasound. Multivariable-adjusted logistic regression models were used to estimate the association of circulating α- and γ-tocopherol/cholesterol ratio levels with prevalent gallstone disease. Lower probabilities of having gallstone disease were observed in the top (compared to the bottom) tertile of the plasma α-tocopherol/cholesterol ratio in multivariable-adjusted models (OR (Odds Ratio): 0.31; 95% CI (Confidence Interval): 0.13–0.76). A lower probability of having gallstone disease was also observed for the γ-tocopherol/cholesterol ratio, though the association did not reach statistical significance (OR: 0.77; 95% CI: 0.35–1.69 for 3rd vs 1st tertile). In conclusion, our observations are consistent with the concept that higher vitamin E levels might protect from gallstone disease, a premise that needs to be further addressed in longitudinal studies.

Role of the Free Radicals in Mechanisms of Gallstone Formation: An EPR Study

The mechanism of gallstone formation is not well understood. Abnormal regulation of hepatic cholesterol, bile acid synthesis or esterification, deposition of cholesterol monohydrate crystals and gall bladder dysfunction are thought to be the principal metabolic aberrations that may cause gallstone formation. One plausible mechanism leading to these abnormalities is the role of free radicals, whose presence can be investigated using Electron Paramagnetic Resonance (EPR). Surgically removed gall bladder stones were used to obtain purified bilirubin, which was irradiated in vitro with visible light and measured with EPR in the presence of and without oxygen. EPR detected oxidized bilirubin free radical (BFR) (g = 2.003, ΔH = 1.0 mTl) in the gallstones. In vitro exposure of bilirubin to visible light in the presence of oxygen induced BFR formation; its intensity was radiation time dependent and decreased under the influence of β-carotene; irradiation in a vacuum did not generate BFRs. These results indicate the important role of oxidative processes (oxidation of bilirubin) in the gallstone formation. In oxidative stress, bilirubin acting as a second type photosensitizer undergoes rapid oxidation and free radical polymerization that plays an important role in the nucleation and deposition of gallstones.

Evaluation of paraoxonase, malondialdehyde, and lipoprotein levels in patients with asymptomatic cholelithiasis

BACKGROUND/AIM

To compare lipoprotein and malondialdehyde levels and paraoxonase-1 activity between subjects with asymptomatic cholelithiasis and controls.

PATIENTS AND METHODS

Eighty subjects with asymptomatic cholelithiasis (55 women, 25 men, mean age: 51, SD 14 years) and 40 control subjects without cholelithiasis (25 women, 25 men, mean age: 51, SD 12 years) were enrolled to the study. Serum paraoxonase activity, lipoproteins, and malondialdehyde were measured.

RESULTS

In the cholelithiasis group, serum total cholesterol, low-density lipoprotein cholesterol, and malondialdehyde were significantly higher and high-density lipoprotein cholesterol (HDL-C) and paraoxonase-1 were significantly lower than the controls. In cholelithiasis patients with serum glucose level>100 mg/dL, body mass index, serum total cholesterol, triglyceride (TG), and malondialdehyde levels were significantly higher than cholelithiasis patients with serum glucose level<100 mg/dL. Paraoxonase-1 activity was significantly lower in patients with serum glucose level>100 mg/dL. In cholelithiasis patients with TG>150 mg/dL, mean age, body mass index, glucose, total cholesterol, and malondialdehyde were significantly higher than in cholelithiasis patients with TG<150 mg/dL. In cholelithiasis subgroup with TG>150 mg/dL, HDL-C level and paraoxonase-1 activity were lower than in the cholelithiasis subgroup with TG<150 mg/dL. All of the above comparisons were statistically significant (P<0.05).

CONCLUSIONS

Patients with asymptomatic cholelithiasis have evidence of increased lipid peroxidation and decreased antioxidant capacity. Patients with asymptomatic cholelithiasis with components of the metabolic syndrome have more lipid peroxidation and less antioxidant capacity than patients with asymptomatic cholelithiasis but without the components of the metabolic syndrome.

Raphanus sativus L. var niger as a source of phytochemicals for the prevention of cholesterol gallstones

Raphanus sativus L. var niger (black radish) is a plant of the cruciferous family with important ethnobotanical uses for the treatment of gallstones in Mexican traditional medicine. It has been established that the juice of black radish decreases cholesterol levels in plasma and dissolves gallstones in mice. Glucosinolates, the main secondary metabolites of black radish, can hydrolyze into its respective isothiocyanates and have already demonstrated antioxidant properties as well as their ability to diminish hepatic cholesterol levels; such therapeutic effects can prevent the formation of cholesterol gallstones. This disease is considered a current problem of public health. In the present review, we analyze and discuss the therapeutic effects of the main glucosinolates of black radish, as well as the effects that this plant has on cholesterol gallstones disease.

Hyperhomocysteinemia from trimethylation of hepatic phosphatidylethanolamine during cholesterol cholelithogenesis in inbred mice

Because hyperhomocysteinemia can occur in cholesterol gallstone disease, we hypothesized that this may result from trimethylation of phosphatidylethanolamine (PE), which partakes in biliary phosphatidylcholine (PC) hypersecretion during cholesterol cholelithogenesis. We fed murine strains C57L/J, C57BL/6J, SWR/J, AKR/J, PE N-methyltransferase (PEMT) knockout (KO), PEMT heterozygous (HET), and wildtype (WT) mice a cholesterol/cholic acid lithogenic diet (LD) for up to 56 days and documented biliary lipid phase transitions and secretion rates. We quantified plasma total homocysteine (tHcy), folate, and vitamin B12 in plasma and liver, as well as biliary tHcy and cysteine secretion rates. Rate-limiting enzyme activities of PC synthesis, PEMT and cytidine triphosphate: phosphocholine cytidylyltransferase (PCT), S-adenosylmethionine (SAM), and S-adenosylhomocysteine (SAH) were measured in liver homogenates. Other potential sources of plasma tHcy, glycine N-methyltransferase (GNMT) and guanidinoacetate N-methyltransferase (GAMT), were assayed by gene expression. Plasma tHcy and PEMT activities became elevated during cholelithogenesis in gallstone-susceptible C57L, C57BL/6, and SWR mice but not in the gallstone-resistant AKR mice. Persisting in C57L mice, which exhibit the greatest Lith gene burden, these increases were accompanied by elevated hepatic SAM/SAH ratios and augmented biliary tHcy secretion rates. Counter-regulation included remethylation of Hcy to methionine concurrent with decreased folate and vitamin B12 levels and Hcy transsulfuration to cysteine. Concomitantly, methylenetetrahydrofolate reductase (Mthfr), betaine-homocysteine methyltransferase (Bhmt), and cystathionine-β-synthase (Cbs) were up-regulated, but Gnmt and Gamt genes were down-regulated. PEMT KO and HET mice displayed biliary lipid secretion rates and high gallstone prevalence rates similar to WT mice without any elevation in plasma tHcy levels.

CONCLUSION

This work implicates up-regulation of PC synthesis by the PEMT pathway as a source of elevated plasma and bile tHcy during cholesterol cholelithogenesis.

Menopause: a review on the role of oxygen stress and favorable effects of dietary antioxidants

Menopause is often accompanied by hot flashes and degenerative processes such as arteriosclerosis and atrophic changes of the skin that suggest an acceleration of aging triggered by estrogen lack. Therefore, hormone replacement therapy (HRT) has been considered the most suitable treatment for the above symptoms and processes. However, because of the possible serious side effects of HRT (especially the increased risk of thrombo-embolic accidents and breast cancer) there is a growing demand for alternative treatments of the symptoms and pathological processes associated with menopause. In agreement with the above, we review research that supports the concept that oxygen stress contributes to menopause and that some of its physiopathological effects may be prevented and/or treated improving the antioxidant defense of menopausic and postmenopausic women. Accordingly, a selection of micronutrients may be useful as a dietary supplement for protection against the decline of physiological functions caused by age-related oxygen stress. Since aging is accompanied by a progressive oxidation of the physiological sulfur pool, we emphasize the role of the vitamins B that help to maintain the GSH/GSSG ratio in its normal reduced state. Nutritional supplements should also include the key antioxidant vitamins C and E, as well as beta-carotene and the mineral micronutrients found in the oxygen radical-detoxifying enzymes glutathione peroxidase and superoxide dismutase. Moreover, the reviewed data suport the concept that other antioxidants such as lipoic acid and the precursors of glutathione thioproline (TP) and l-2-oxothiazolidine-4-carboxylic acid (OTC), as well as the soy isoflavones and the "coantioxidants" of an hydroalcoholic extract of Curcuma longa may help to prevent antioxidant deficiency with resulting protection of mitochondria against premature oxidative damage with loss of ATP synthesis and especialized cellular functions. Therefore, the administration under medical advice of synergistic combinations of some of the above mentioned antioxidants in the diet as well as topically (for skin protection) may have favorable effects on the health and quality of life of women, especially of those who cannot be treated with HR, suffer high levels of oxygen stress, and do not consume a healthy diet that includes five daily rations of fresh fruit and vegetables.

Gallstone disease: Epidemiology of gallbladder stone disease

Gallstone disease is common: >700,000 cholecystectomies and costs of approximately 6.5 billion dollars annually in the U.S. The burden of disease is epidemic in American Indians (60-70%); a corresponding decrease occurs in Hispanics of mixed Indian origin. Ten to fifteen per cent of white adults in developed countries harbour gallstones. Frequency is further reduced in Black Americans, East Asia and sub-Saharan Africa. In developed countries, cholesterol gallstones predominate; 15% are black pigment. East Asians develop brown pigment stones in bile ducts, associated with biliary infection or parasites, or in intrahepatic ducts (hepatolithiasis). Certain risk factors for gallstones are immutable: female gender, increasing age and ethnicity/family (genetic traits). Others are modifiable: obesity, the metabolic syndrome, rapid weight loss, certain diseases (cirrhosis, Crohn's disease) and gallbladder stasis (from spinal cord injury or drugs like somatostatin). The only established dietary risk is a high caloric intake. Protective factors include diets containing fibre, vegetable protein, nuts, calcium, vitamin C, coffee and alcohol, plus physical activity.

Plasma total homocysteine and gallstone in middle-aged Japanese men

BACKGROUND

We wished to determine whether selected coronary risk factors correlated with the presence of gallstone (GS) in middle-aged Japanese men.

METHODS

We carried out a cross-sectional study of 974 male Self-Defense officials. The odds ratio of a 1-SD increment in levels of coronary risk factors for the presence of GS was calculated in a logistic regression analysis.

RESULTS

Nine subjects had undergone cholecystectomy. Gallstone was detected in 39 subjects and not in 926 subjects. The presence of GS was associated with total homocysteine (tHcy), but not with total cholesterol, triglyceride, gamma-glutamyl transferase, glucose, or folate. The odds ratio of a 2.8-micromol/l increase (1 SD) in tHcy levels for the presence of GS was 1.34 (95% confidence interval [CI], 1.05-1.69; P = 0.017), and the ratio was 1.33 (95% CI, 1.04-1.70; P = 0.025) after being adjusted for lifestyle factors, including cigarette smoking, vegetable intake, physical activity, and abstention from alcohol.

CONCLUSIONS

Plasma tHcy, but not the other coronary risk factors, correlated with the presence of GS in middle-aged Japanese men. This association may partly explain the reported high prevalence rate of coronary heart disease in subjects with GS.