Abnormalities of lipid metabolism, gallstone disease and gallbladder function

Targeted LC-MS/MS Profiling of Bile Acids in Various Animal Tissues

Bile acids are being increasingly investigated in humans and laboratory animals as markers for various diseases in addition to their important functions, such as promoting the emulsification in fat digestion and preventing gallstone formation. In humans and animals, primary bile acids are formed from cholesterol in the liver, converted in the intestine into various secondary bile acids by the intestinal microbiota and reabsorbed in the terminal ileum, and partially returned to the liver. A universal high-throughput workflow, including a simple workup, was applied as a tool for bile acid analysis in animal studies. The complex bile acid profiles in various tissues, organs, and body fluids from different animals were mapped using a newly developed comprehensive liquid chromatography-tandem mass spectrometry method. The method can also be used in screening food to obtain information about the nutritional content of bile acids. This could be relevant to investigations on various animal diseases and on the bioavailability of bile acids that pass through the gastric tract.

Cholecystectomy - a potential selection bias in studies assessing the metabolic effects of bariatric surgeries

Bile acids (BAs) are key mediators of the glycemic control after bariatric surgeries. Cholecystectomy modifies the kinetics of BAs, and whether this procedure influences the BAs pool and its metabolic response to bariatric surgeries is not known. We used targeted and untargeted metabolomics to assess whether cholecystectomy influenced plasma and fecal BAs fluctuations and the systemic metabolomic profile after Roux-en-Y gastric bypass (RYGB). Women with obesity and type 2 diabetes were included. Sample collections and clinical evaluations were performed before and 3 months after RYGB. RYGB influenced 9 fecal and 3 plasma BAs in patients with cholecystectomy (p ≤ 0.05). Comparisons between patients with and without cholecystectomy revealed different concentrations of 4 fecal and 5 plasma BAs (p ≤ 0.05). Cholecystectomy impacted the global metabolomics responses to RYGB, and patients who underwent the gallbladder removal also lacked some significant improvements in clinical markers, primarily the lipid profile. By affecting the BAs concentrations, cholecystectomy seems to alter the systemic metabolic response to RYGB. Therefore, cholecystectomy may act as a bias in assessments of the metabolic effects of bariatric surgeries and their relationships with clinical outcomes.

Etiologies of Long-Term Postcholecystectomy Symptoms: A Systematic Review

Background

Cholecystectomy does not relieve abdominal symptoms in up to 40% of patients. With 700,000 cholecystectomies performed in the US, annually, about 280,000 patients are left with symptoms, making this a serious problem. We performed a systematic review to determine the different etiologies of long-term postcholecystectomy symptoms with the aim to provide guidance for clinicians treating these patients.

Methods

A systematic search of the literature was performed using MEDLINE, EMBASE, and Web of Science. Articles describing at least one possible etiology of long-term symptoms after a laparoscopic cholecystectomy were included in this review. Long-term symptoms were defined as abdominal symptoms that were present at least four weeks after cholecystectomy, either persistent or incident. The etiologies of persistent and incident symptoms after LC and the mechanism or hypothesis behind the etiologies are provided. If available, the prevalence of the discussed etiology is provided.

Results

The search strategy identified 3320 articles of which 130 articles were included. Etiologies for persistent symptoms were residual and newly formed gallstones (41 studies, prevalence ranged from 0.2 to 23%), coexistent diseases (64 studies, prevalence 1-65%), and psychological distress (13 studies, no prevalence provided). Etiologies for incident symptoms were surgical complications (21 studies, prevalence 1-3%) and physiological changes (39 studies, prevalence 16-58%). Sphincter of Oddi dysfunction (SOD) was reported as an etiology for both persistent and incident symptoms (21 studies, prevalence 3-40%).

Conclusion

Long-term postcholecystectomy symptoms vary amongst patients, arise from different etiologies, and require specific diagnostic and treatment strategies. Most symptoms after cholecystectomy seem to be caused by coexistent diseases and physiological changes due to cholecystectomy. The outcome of this research is summarized in a decision tree to give clinical guidance on the treatment of patients with symptoms after cholecystectomy.

Effect of cholecystectomy on hepatic fat accumulation and insulin resistance in non-obese Hispanic patients: a pilot study

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is highly prevalent worldwide. Experimental studies have shown that cholecystectomy (XGB) increases hepatic fat content in mice and appears associated to NAFLD in large retrospective population-based studies. The aim of this study was to prospectively assess the effects of XGB on hepatic fat content (HFC) and insulin resistance (IR) in non-obese, middle aged Hispanic subjects.

METHODS

Twenty-six gallstone patients undergoing elective XGB and 16 control subjects with normal livers and gallbladders at ultrasonography were prospectively followed 24 months for changes in HFC and IR. Clinical, biochemical determinations and hepatic imaging were performed at baseline and 24 months after surgery. MRI technique quantified HFC in four hepatic segments. IR was assessed by the Homeostasis Model Assessment (HOMA_-IR) index.

RESULTS

Initial body mass index (BMI) was 25.6 ± 0.4 and 24.3 ± 1.0 in the control and XGB groups of subjects, respectively. Serum insulin level increased from 8.1 ± 0.7 to 10.0 ± 1.9 (μU/ml) 24 months after surgery in XGB patients (p < 0.05); no significant changes were detected in control individuals. Median HOMA_-IR index increased from 1.31 (interquartile range, 1.01-1.68) to 2.20 (interquartile range, 1.57 - 2.60) 24 months after XGB, (p < 0.003). Median HOMA_-IR index of control subjects remained unchanged at the end of the study. Serum apoB concentration increased from 61.5 ± 3.4 to 79.0 ± 7.8 (μg/ml) in XGB patients (p < 0.03). Serum apoB levels remained within normal ranges in both periods of the study in control subjects. HFC significantly increased in 2 of the 4 segments 24 months after XGB: right posterior hepatic lobe (from 5.3 ± 0.2% to 6.0 ± 0.2%, p > 0.04) and right anterior hepatic lobe (from 5.8 ± 0.2% to 6.6 ± 0.3%, p < 0.02). The average HFC of the four hepatic segments studied slightly increased from 5.4 ± 0.2 to 5.8 ± 0.3 2 years after XGB (p < 0.03). No significant changes were found in HFC in the control subjects at the end of the study.

CONCLUSIONS

Elective XGB increases HFC, HOMA_-IR index and serum apoB concentration. These results support the notion that XGB is a risk factor non-alcoholic fatty liver disease and other IR - associated disease conditions.