Calcium, magnesium, and free fatty acids in the formation of gallstones: a nested case-control study

Human bile as a rich source of biomarkers for hepatopancreatobiliary cancers

Metabolic profiling of biofluids is emerging as an important area with a promising number of applications in clinical medicine, including early diagnosis of numerous diseases that normally remain silent until late in the progress of disease. While blood and urine are more often used to explore biomarkers that distinguish he healthy from disease conditions, human bile is emerging as a rich source of biomarkers specifically for the cancers of the liver (hepatocellular carcinoma), bile ducts (cholangiocarcinoma), gallbladder and pancreas. This is owing to the fact that metabolites linked to the pathways of tumor cell metabolism are rich in bile by virtue of its association or proximity to the pathological source. Recent methodological developments have enabled the identification of a number of bile metabolites that have links with hepatopancreatobiliary diseases. Investigations of human bile are also considered to help the biomarker discovery process in vitro and provide avenues for translational research in detecting and following dynamic variations of biomarkers in clinical settings using noninvasive approaches, such as in vivo magnetic resonance spectroscopy. This article reviews the current status and potential applications of human bile as a source of biomarkers, with emphasis on metabolites, for early detection of cancers associated with the hepatopancreatobiliary system.

Stones from cancerous and benign gallbladders are different: A proton nuclear magnetic resonance spectroscopy study

AIM

Gallbladder cancer (GBC) is frequently associated with gallstones (GS). At the same time, however, a very small number of patients with GS develop GBC. Cholesterol and metal salts are the common constituents of all GS. To understand their role in the etiopathogenesis of GBC, cholesterol, calcium, and magnesium composition in GS is compared in cancerous and benign gallbladders.

METHODS

GS from patients with GBC (n = 11), chronic cholecystitis (CC; n = 23), and xanthogranulomatous cholecystitis (XGC; n = 11) undergoing cholecystectomy were analyzed using proton nuclear magnetic resonance spectroscopy. The diagnosis of the gallbladder disease was based on histopathological examinations. Cholesterol, calcium, and magnesium in the GS of GBC, XGC, and CC were analyzed, compared, and correlated using statistical methods.

RESULTS

The quantity of cholesterol was significantly less in the GS of GBC than in benign gallbladder diseases (CC or XGC, P < 0.0001 for both). Both calcium and magnesium were significantly higher in GBC than in benign disease (calcium: P < 0.0005 and magnesium: P < 0.0001 for GBC vs CC; calcium: P < 0.02 and magnesium: P < 0.04 for GBC vs XGC). In all the GS, calcium was higher than magnesium. Calcium and magnesium were positively correlated in GBC (R = 0.69) and XGC (R = 0.75), and cholesterol and calcium were negatively correlated in CC (R =-0.61).

CONCLUSION

Differences in the GS composition between malignant and benign gallbladder patients may provide useful clues to the etiopathogenesis of GBC. These clues could lead to the identification of patients with GS in vivo who are at high risk of developing GBC, and advocate prophylactic cholecystectomy to prevent GBC.

Long-term effect of magnesium consumption on the risk of symptomatic gallstone disease among men

BACKGROUND

Magnesium deficiency can cause dyslipidemia and insulin hypersecretion, which may facilitate gallstone formation. However, the effect of long-term consumption of magnesium on the risk of gallstone disease is unknown.

METHODS

We prospectively studied magnesium consumption and risk of gallstone disease in a cohort of 42,705 U.S. men from 1986 to 2002. Magnesium consumption was assessed using a validated semiquantitative food frequency questionnaire. Newly diagnosed gallstone disease was ascertained biennially.

RESULTS

We documented 2,195 incident cases of symptomatic gallstones during 560,810 person-years of follow-up. The age-adjusted relative risks (RRs) for men with total magnesium intake and dietary magnesium, when the highest and lowest quintiles were compared, were 0.67 (95% confidence interval [CI] 0.59-0.77, P for trend <0.0001) and 0.67 (CI 0.59-0.76, P for trend <0.0001), respectively. After adjusting for multiple potential confounding variables, when extreme quintiles were compared, the multivariate RR of total magnesium intake (RR 0.72, CI 0.61-0.86, P for trend = 0.006) and dietary magnesium (RR 0.68, CI 0.57-0.82, P for trend = 0.0006) remained significant with a dose-response relationship.

CONCLUSIONS

Our findings suggest a protective role of magnesium consumption in the prevention of symptomatic gallstone disease among men.

Higher incidence of cholelithiasis in chronic renal failure patients with secondary hyperparathyroidism undergoing peritoneal dialysis

BACKGROUND

In this study, we endeavored to determine whether the incidence of cholelithiasis (CL) was increased in chronic renal failure (CRF) patients with secondary hyperparathyroidism on a peritoneal dialysis (PD) program. We also evaluated the factors that might have some influence on the development of CL.

METHODS

A total of 59 CRF patients undergoing PD were included in the study. We studied the following groups to determine whether parathyroid hormone (PTH) levels were increased in CRF-PD patients: twenty patients with secondary hyperparathyroidism (group 1) and 39 patients with normal PTH levels (group 2). PTH levels were maintained at three times the upper limit of normal. Biochemical parameters were obtained for each CRF-PD patient. All patients underwent abdominal ultrasonography to screen for the presence of cholelithiasis. For statistical analysis, chi2, t test, and logistic regression analysis were used; p < 0.05 was considered as significant.

RESULTS

We found an almost ten times higher incidence (25% vs. 2.6%) of CL in group 1 patients with statistical significance (p = 0.007). When the incidence of CL according to sex, creatinine, and PTH levels were considered, female gender, creatinine, and PTH levels were higher in group 1, which was also significant statistically. No significant relationship was detected between gallbladder stone formation and the other analyzed biochemical parameters.

CONCLUSIONS

We found that the incidence of CL in CRF-PD patients with secondary hyperparathyroidism was higher than CRF-PD patients with normal PTH levels. It was also detected that female gender, high creatinine levels, and elevated PTH levels might influence the development of CL in CRF-PD patients.

Association of bowel movement frequency and use of laxatives with the occurrence of symptomatic gallstone disease in a prospective study of women

OBJECTIVES

The authors prospectively examined the association between bowel movement frequency (used as a proxy for intestinal transit), laxative use, and the risk of symptomatic gallstone disease.

METHODS

A total of 79,829 women, aged 36-61 yr, without a history of symptomatic gallstone disease and free of cancer, responded to a mailed questionnaire in 1982 that assessed bowel movement frequency and use of laxatives. Between 1984 and 1996, 4,443 incident cases of symptomatic gallstone disease were documented. Relative risks (RRs) of symptomatic gallstone disease and 95% confidence intervals (CIs) were calculated using logistic regression.

RESULTS

After controlling for age and established risk factors, the multivariate RRs were, compared to women with daily bowel movements, 0.97 (95% CI 0.86-1.08) for women with bowel movements every third day or less, and 1.00 (95% CI 0.91-11.1) for women with bowel movement more than once daily. No trend was evident. As compared to women who never used laxatives in 1982, a significant modest inverse association was seen for monthly laxative use, with a multivariate RR of 0.84 (95% CI 0.72-0.98), and weekly to daily laxative use was associated with a RR of 0.88 (95% CI 0.78-1.02).

CONCLUSIONS

These findings do not support an association between infrequent bowel movements and risk of symptomatic gallstone disease in women, and indicate that simple questions directed at bowel movement frequency are unlikely to enhance our ability to predict risk of symptomatic gallstone disease. The slightly inverse association between use of laxatives and risk of symptomatic gallstone disease may be due to a mechanism that is not related to bowel movement frequency.

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) relax cholecystokinin-induced tension in guinea pig gallbladder strips

Parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) have been shown to relax various types of smooth muscle, e.g. vascular, uterine and gastric. This study demonstrates that PTH and PTHrP both relaxed cholecystokinin octapeptide (CCK)-induced tension in guinea pig gallbladder strips. This relaxation was concentration-dependent. The use of PTHrP (7-34) blocked the relaxant effect of both agents. This suggested PTH and PTHrP were acting through the same receptor. The use of Rp-cAMPs, an inhibitor of cAMP activation of protein kinase A, and H-89, a selective inhibitor of protein kinase A, suggested that cAMP mediated the relaxant action of PTH and PTHrP. The use of iberiotoxin indicated that the high conductance Ca(2+)-activated potassium channels also mediated the actions of PTH/PTHrP. The use of KT5823, a selective blocker of protein kinase G, also decreased the amount of relaxation induced by PTH/PTHrP. This suggested that crosstalk between the two second messenger (cAMP and cGMP) systems occurred.

Lack of relationship between serum and gallbladder bile calcium in patients with gallstone disease

BACKGROUND

Recent studies suggest that alternation in serum calcium influences the level of gallbladder bile ionized calcium (Ca2+). Theoretically, this could increase the risk of calcium precipitation in the gallbladder.

METHODS

We therefore measured serum and gallbladder bile minerals in patients with gallstones (n = 27) and without (n = 10, controls). The serum samples were taken just prior to induction of anaesthesia and gallbladder bile was aspirated before any manipulation of the gallbladder.

RESULTS

The active molality of Ca2+ in gallbladder bile was not statistically significant different between cases and controls (0.44 +/- 0.16 vs. 0.40 +/- 0.10 mmol/kg), whereas pH was significantly lower (6.94 +/- 0.31 vs. 7.36 +/- 0.28, p < 0.0001) and cholesterol higher (4.37 +/- 2.70 vs. 1.79 +/- 1.33 mmol/l; p < 0.01) in gallbladder bile obtained from cases. Serum Ca2+ at actual pH, magnesium and phosphate were significantly higher among cases than in controls. Gallbladder bile active molality of Ca2+ was significantly correlated with bile total calcium in both groups (r = 0.72; p < 0.001 and r = 0.91; p < 0.001, respectively). In controls only, we observed a positive relationship between serum Ca2+ at actual pH and the active molality of Ca2+ in bile (r = 0.61; p < 0.05).

CONCLUSION

Our study demonstrates that Ca2+ in gallbladder bile does not differ between cases and controls. The lack of correlation between serum and gallbladder bile constituents in cases compared to controls suggests that changes in calcium equilibration between bile and serum in patients with gallstone disease might be of importance for the formation of gallstones.