The effects of serum cholesterol, LDL, and HDL levels on gallstone cholesterol concentration

Can Lipid-Lowering Drugs Reduce the Risk of Cholelithiasis? A Mendelian Randomization Study

Background and Aims

Cholelithiasis etiology intricately involves lipid metabolism. We sought to investigate the plausible causal link between genetically proxied lipid-lowering medications-specifically HMGCR inhibitors, PCSK9 inhibitors, and NPC1L1 inhibitors-and cholelithiasis risk.

Methods

Our study utilized two genetic instruments for exposure to lipid-lowering drugs. These instruments encompassed genetic variants linked to low-density lipoprotein (LDL) cholesterol within or in proximity to drug target genes, along with loci governing gene expression traits of these targets. Effect estimates were derived through Inverse-variance-weighted MR (IVW-MR) and summary-data-based MR (SMR) methods.

Results

Higher HMGCR-mediated LDL cholesterol levels (IVW-MR, OR = 2.15, 95% CI = 1.58-2.94; P = 0.000) and increased HMGCR expression (SMR, OR = 1.19, 95% CI = 1.04-1.37; P = 0.014) are linked to elevated cholelithiasis risk, suggesting potential benefits of HMGCR inhibition. In contrast, higher PCSK9-mediated LDL cholesterol levels (IVW-MR, OR = 0.72, 95% CI = 0.56-0.94; P = 0.015) and increased PCSK9 expression (SMR, OR = 0.90, 95% CI = 0.82-0.99; P = 0.035) both correlate with lower cholelithiasis risk, indicating that PCSK9 inhibition may elevate this risk. Nevertheless, no substantial link emerged between NPC1L1-mediated LDL cholesterol or NPC1L1 expression and cholelithiasis in both IVW-MR and SMR analyses.

Conclusion

This MR investigation affirms the causal link between the utilization of HMGCR inhibitors and a diminished risk of cholelithiasis. Additionally, it indicates a causal link between PCSK9 inhibitors use and increased cholelithiasis risk. However, no significant correlation was found between NPC1L1 inhibitors use and cholelithiasis risk.

Causal associations between changes in lipid profiles and risk of gallstone disease: a two-sample Mendelian randomization study

Background

Nonalcoholic fatty liver disease (NAFLD) has been linked to gallstone disease (GSD) in observational studies; however, the relationships between certain lipid profiles and GSD remain unclear.

Methods

We adopted a two-sample Mendelian randomization (MR) framework by applying different statistical methods to assess causalities between lipid profiles and GSD. We identified single-nucleotide polymorphisms (SNPs) for blood lipids and NAFLD from separate previous genome-wide association studies (GWASs).

Results

We retrieved GSD SNPs attributed to 10,520 cases and 361,194 controls and validated our estimates using GWAS summary data from UK Biobank. We also performed sex-stratified analyses. Based on the summary estimates of 41, 59, 35, and 2 SNPs for low-density lipoprotein cholesterol (LDLC), high-density lipoprotein cholesterol (HDLC), triglycerides (TGs), and NAFLD, respectively, we found no evidence of a causal relationship between genetically-predicted lipid profiles and GSD. The odds ratios were 0.995 for LDLC [95% confidence interval (CI): 0.994-0.998] per 0.98 mmol/L, 0.999 for HDLC (95% CI: 0.996-1.003) per 0.41 mmol/L, 0.997 for TGs (95% CI: 0.994-1.001) per 1 mmol/L, and 0.993 for NAFLD (95% CI: 0.984-1.003). No evidence of associations between lipid profile s and GSD in validation MR analyses or the sex-stratification analyses was noted.

Conclusions

Genetically predicted hyperlipidemia or NAFLD is not causally associated with GSD.

Insights into modifiable risk factors of cholelithiasis: A Mendelian randomization study

BACKGROUND AND AIMS

The risk factors of cholelithiasis have not been clearly identified, especially for total cholesterol. Here, we try to identify these causal risk factors.

APPROACH AND RESULTS

We obtained genetic variants associated with the exposures at the genome-wide significance (p < 5 × 10^-8 ) level from corresponding genome-wide association studies. Summary-level statistical data for cholelithiasis were obtained from FinnGen and UK Biobank (UKB) consortia. Both univariable and multivariable Mendelian randomization (MR) analyses were conducted to identify causal risk factors of cholelithiasis. Results from FinnGen and UKB were combined using the fixed-effect model. In FinnGen, the odds of cholelithiasis increased per 1-SD increase of body mass index (BMI) (OR = 1.631, p = 2.16 × 10^-7 ), together with body fat percentage (OR = 2.108, p = 4.56 × 10^-3 ) and fasting insulin (OR = 2.340, p = 9.09 × 10^-3 ). The odds of cholelithiasis would also increase with lowering of total cholesterol (OR = 0.789, p = 8.34 × 10^-5 ) and low-density lipoprotein-cholesterol (LDL-C) (OR = 0.792, p = 2.45 × 10^-4 ). However, LDL-C was not significant in multivariable MR. In UKB, the results of BMI, body fat percentage, total cholesterol, and LDL-C were replicated. In meta-analysis, the liability to type 2 diabetes mellitus and smoking could also increase the risk of cholelithiasis. Moreover, there were no associations with other predominant risk factors.

CONCLUSIONS

Our MR study corroborated the risk factors of cholelithiasis from previous MR studies. Furthermore, lower total cholesterol level could be an independent risk factor.

Cholesterol crystals activate NLRP3 inflammasomes and promote gallstone formation by increasing mucin secretion

Cholesterol crystals participate in cholesterol nucleation; however, the role of cholesterol crystals in gallstone development is unknown. Mucin secretion contributes to increased size of gallstones. Cholesterol crystals activate inflammasomes and participate in many sterile inflammation related human diseases. We investigated the role of cholesterol crystals and mucins in sterile inflammation and gallstone enlargement. We found that expression of mucin 5AC (MUC5AC), NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) and interleukin-1b (IL-1b) was increased significantly in tissues adjacent to gallstones. Experiments in vitro showed that cholesterol crystals promote MUC5AC secretion; they also increase expression of NLRP3, NLR family CARD domain-containing 4 (NLRC4), apoptosis-associated speck-like protein containing caspase recruitment domain (ASC), and cleaved caspase-1 in biliary epithelial cells. Inhibition of Inflammasomes by NLRP3, ASC or caspase-1 small interfering RNAs reduced MUC5AC secretion. Also, the IL-1 receptor antagonist, IL1RA, and caspase-1 inhibitor, Ac-YVAD, both inhibited MUC5AC secretion induced by cholesterol crystals. We found that inflammasome activation participates in cholesterol crystal induced mucin secretion and gallstone development.

Environmental and Lifestyle Risk Factors in the Carcinogenesis of Gallbladder Cancer

Gallbladder cancer (GBC) is an aggressive neoplasm that in an early stage is generally asymptomatic and, in most cases, is diagnosed in advanced stages with a very low life expectancy because there is no curative treatment. Therefore, understanding the early carcinogenic mechanisms of this pathology is crucial to proposing preventive strategies for this cancer. The main risk factor is the presence of gallstones, which are associated with some environmental factors such as a sedentary lifestyle and a high-fat diet. Other risk factors such as autoimmune disorders and bacterial, parasitic and fungal infections have also been described. All these factors can generate a long-term inflammatory state characterized by the persistent activation of the immune system, the frequent release of pro-inflammatory cytokines, and the constant production of reactive oxygen species that result in a chronic damage/repair cycle, subsequently inducing the loss of the normal architecture of the gallbladder mucosa that leads to the development of GBC. This review addresses how the different risk factors could promote a chronic inflammatory state essential to the development of gallbladder carcinogenesis, which will make it possible to define some strategies such as anti-inflammatory drugs or public health proposals in the prevention of GBC.

Association between metabolic syndrome and incidence of cholelithiasis in the Korean population

BACKGROUND AND AIM

Cholelithiasis is one of the most common gastrointestinal diseases worldwide. The metabolic syndrome (MetS), a combination of various metabolic abnormalities, is also common with a continually increasing prevalence. These diseases are associated with several risk factors. However, data on the association between MetS components and cholelithiasis are insufficient. This study aimed to analyze the association of MetS and its components with the incidence of cholelithiasis using national data from the Korean population.

METHODS

Data were obtained from the National Health Insurance Corporation of Korea, and 207 850 individuals without cholelithiasis in 2009 were enrolled and followed up until 2013. A multivariate Cox proportional hazard model was used to calculate the adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of cholelithiasis according to the presence of MetS and the number of MetS components. Furthermore, the risk of cholelithiasis was evaluated in individuals with a single metabolic component.

RESULTS

The multivariate adjusted HRs and 95% CIs for incident cholelithiasis according to 1, 2, 3, and 4-5 MetS components were 1.08 (0.93-1.24), 1.22 (1.06-1.41), 1.35 (1.17-1.57), and 1.35 (1.15-1.57), respectively (P < 0.001). This increasing trend was observed in both sexes. Compared with participants with no metabolic components, those with low high-density lipoprotein (HDL) cholesterol had a significantly increased risk for cholelithiasis (adjusted HR, 1.39 [95% CI, 1.05-1.85]).

CONCLUSIONS

Metabolic syndrome is a potential risk factor for cholelithiasis. Low HDL cholesterol level is the most relevant factor among MetS components for incident cholelithiasis.

Hepatic expression of cholesterol regulating genes favour increased circulating low-density lipoprotein in HIV infected patients with gallstone disease: a preliminary study

BACKGROUND

HIV endemic populations are displaying higher incidence of metabolic disorders. HIV and the standard treatment are both associated with altered lipid and cholesterol metabolism, however gallstone disease (a cholesterol related disorder) in Sub-Saharan African populations is rarely investigated.

METHODS

This study sought to evaluate hepatic expression of key genes in cholesterol metabolism (LDLr, HMGCR, ABCA1) and transcriptional regulators of these genes (microRNA-148a, SREBP2) in HIV positive patients on antiretroviral therapy presenting with gallstones. Liver biopsies from HIV positive patients (cases: n = 5) and HIV negative patients (controls: n = 5) were analysed for miR-148a and mRNA expression using quantitative PCR.

RESULTS

Circulating total cholesterol was elevated in the HIV positive group with significantly elevated LDL-c levels(3.16 ± 0.64 mmol/L) relative to uninfected controls (2.10 ± 0.74 mmol/L; p = 0.04). A scavenging receptor for LDL-c, LDLr was significantly decreased (0.18-fold) in this group, possibly contributing to higher LDL-c levels. Transcriptional regulator of LDLr, SREBP2 was also significantly lower (0.13-fold) in HIV positive patients. Regulatory microRNA, miR-148a-3p, was reduced in HIV positive patients (0.39-fold) with a concomitant increase in target ABCA1 (1.5-fold), which regulates cholesterol efflux.

CONCLUSIONS

Collectively these results show that HIV patients on antiretroviral therapy display altered hepatic regulation of cholesterol metabolizing genes, reducing cholesterol scavenging, and increasing cholesterol efflux.

Effect and related mechanism of Yinchenhao decoction on mice with lithogenic diet-induced cholelithiasis

The aim of the present study was to investigate the effects and the underlying mechanisms of Yinchenhao Decoction (YCHD), a traditional Chinese medicine formulation, on C57BL/6 mice with lithogenic diet (LD)-induced cholelithiasis. The condition of cholelithiasis was evaluated using a six-level criteria. Levels of alanine aminotransferase (ALT), alkaline phosphatase (ALP), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) in the serum and liver tissue were measured using enzyme colorimetry. Concentrations of TC, phospholipids (PL) and total bile acids (TBA) in the bile were measured to calculate the cholesterol saturation index. Liver histopathology was microscopically observed and mRNA expression levels of ABCG5, ABCG8, SRBI, ABCB4, ABCB11 and NPC1L1 involved in cholesterol metabolism were measured using reverse transcription-quantitative PCR. The results showed that feeding mice the LD induced cholelithiasis, along with abnormal serum biochemical indices and imbalances in biliary cholesterol homeostasis. Increased ALT and ALP levels in the serum and ALT, ALP, TC and LDL-C levels in the serum and liver indicated the existence of hepatocyte injury, which were consistent with the pathological changes. YCHD treatment ameliorated the serum and hepatic biochemical abnormalities and adjusted the biliary imbalance. In addition, elevated expression of ATP-binding cassette subfamily G member 5/8, scavenger receptor class B type I and Niemann-Pick C1 Like 1 in the liver and small intestine were observed at the onset of cholelithiasis but were reversed by YCHD. Taken together, results from the present study suggest that YCHD ameliorated LD-induced cholelithiasis mice, which may be caused by improvements in biliary cholesterol supersaturation and regulation of cholesterol metabolism.

Relationship Between Gallstone Disease and Cardiometabolic Risk Factors in Elderly People with Non-Alcoholic Fatty Liver Disease

BACKGROUND

The prevalence of gallstone disease (GSD) increases with age, and the elderly have a much higher mortality risk and incidence of surgical comorbidities. The aim of this study was to explore the relationship between GSD and cardiometabolic risk factors in elderly people with non-alcoholic fatty liver disease (NAFLD).

METHODS

In this cross-sectional study, we analyzed the data of elderly people who underwent annual health check-ups at a Northern Taiwan health examination center. These data were collected from physical examination, blood tests, abdominal ultrasonography, and medical histories. We excluded those with hepatitis B or C infections, heavy alcohol consumption, or cholecystectomy.

RESULTS

The analysis included 3,037 participants with a mean age of 73.6±6.0 years. Over 70% were overweight or obese, and the overall prevalence of GSD was 17.7%. In our univariate analysis, GSD was positively correlated with age, body mass index, metabolic syndrome, diabetes mellitus (DM), hypertension (HTN), and various metabolic factors (fasting plasma glucose [FPG], triglyceride, uric acid, and high-density lipoprotein cholesterol [HDL-C] levels). After adjustment for age, gender, and body mass index, metabolic syndrome showed a positive association with GSD (odds ratio [OR] 1.31 [95% confidence interval [CI], 1.05-1.64]; P=0.020). Specific components of metabolic syndrome that increased the risk for GSD in NAFLD elderly include lower levels of HDL-C (OR 1.35 [95% CI, 1.10-1.66]; P<0.001) and elevated FPG (OR 1.36 [95% CI, 1.10-1.69]; P<0.001).

CONCLUSION

Our study concluded that GSD is significantly associated with metabolic syndrome in elderly people with NAFLD. Reduced HDL-C and elevated FPG both heighten the risk of developing GSD. Therefore, to lower the risk of GSD in NAFLD patients, their FPG levels and HDL-C levels must be regularly followed-up, and these patients should be educated about the symptoms of GSD if they meet the criteria for metabolic syndrome.

Plant-Based Diet, Cholesterol, and Risk of Gallstone Disease: A Prospective Study

Vegetarian diets may lower symptomatic gallstone disease via cholesterol lowering. This study aimed to examine the risk of symptomatic gallstone disease (GSD) in Taiwanese vegetarians vs. nonvegetarians in a prospective cohort and to explore if this association is related to cholesterol concentration. We prospectively followed 4839 participants, and in the 29,295 person-years of follow-up, 104 new incident GSD cases were confirmed. Diet was assessed through a validated food frequency questionnaire. Symptomatic GSD was ascertained through linkage to the Taiwan National Health Insurance Research Database. Blood cholesterol profiles were measured at recruitment. Cox regression was applied to assess the effect of diet on symptomatic GSD, adjusting for age, education, smoking, alcohol, physical activities, diabetes, kidney diseases, body mass index, lipid-lowering medication, and hypercholesterolemia. Vegetarian diet was associated with a decreased risk of symptomatic GSD compared with nonvegetarian diet in women (hazard ratio [HR], 0.52; 95% confidence interval [CI], 0.28⁻0.96) but not in men. In women, nonvegetarians with hypercholesterolemia had 3.8 times the risk of GSD compared with vegetarians with normal cholesterol (HR, 3.81, 95% CI, 1.61⁻9.01). A vegetarian diet may therefore protect against GSD independent of baseline hypercholesterolemia. A nonvegetarian diet and hypercholesterolemia may have an additive effect in increasing GSD risk in women.

COMPARATIVE ANALYSIS OF IMMUNOLOGICAL PROFILES IN WOMEN UNDERGOING CONVENTIONAL AND SINGLE-PORT LAPAROSCOPIC CHOLECYSTECTOMY

Background

Surgical trauma triggers an important postoperative stress response characterized by significantly elevated levels of cytokines, an event that can favor the emergence of immune disorders which lead to disturbances in the patient's body defense. The magnitude of postoperative stress is related to the degree of surgical trauma.

Aim

To evaluate the expression of pro-inflammatory (TNF-α, IFN-γ, IL-1β, and IL-17) and anti-inflammatory (IL-4) cytokines in patients submitted to conventional and single-port laparoscopic cholecystectomy before and 24 h after surgery.

Methods

Forty women with symptomatic cholelithiasis, ranging in age from 18 to 70 years, participated in the study. The patients were divided into two groups: 21 submitted to conventional laparoscopic cholecystectomy and 19 to single-port laparoscopic cholecystectomy.

Results

Evaluation of the immune response showed no significant difference in IFN-γ and IL-1β levels between the groups or time points analyzed. With respect to TNF-α and IL-4, serum levels below the detection limit (10 pg/ml) were observed in the two groups and at the time points analyzed. Significantly higher postoperative expression of IL-17A was detected in patients submitted to single-port laparoscopic cholecystectomy when compared to preoperative levels (p=0.0094).

Conclusions

Significant postoperative expression of IL-17 was observed in the group submitted to single-port laparoscopic cholecystectomy when compared to preoperative levels, indicating that surgical stress in this group was higher compared to the conventional laparoscopic cholecystectomy.