Combined microstructural and mineralogical phase characterization of gallstones in a patient-based study in SW Spain - Implications for environmental contamination in their formation

Serum arsenic augments gallstone risk in Henan rural cohort with multiple metal exposure

BACKGROUND

People are exposed to metals in various ways during their daily lives. However, the association between metal exposure and gallstones remains unclear.

OBJECTIVES

To investigate the relationship between serum elemental concentrations and the risk of gallstones.

METHODS

Participants (n = 4204) were drawn from the Henan Rural Cohort. Gallstone diagnosis was based on abdominal ultrasound reports during follow-up. Baseline serum elemental concentrations were measured using inductively coupled plasma mass spectrometry. The relationship between serum elemental levels and gallstones was evaluated using robust Poisson regression, restricted cubic spline (RCS), quantile g-computation (Qgcomp), grouped weighted quantile sum (GWQS) and Bayesian kernel machine regression (BKMR).

RESULTS

121 individuals were diagnosed with gallstone (incidence rate of 2.88 %). In robust Poisson regression, after adjusting for confounding factors, the highest quartile of arsenic concentration compared to the lowest quartile had a 1.90 times higher relative risk (RR) [95 % confidence interval (CI): 1.05, 3.44]. Conversely, the highest quartile of zinc concentration compared to the lowest quartile had a 0.50 times lower RR (95 % CI: 0.28, 0.89). RCS showed an approximately "S"-shaped nonlinear relationship between serum arsenic levels and gallstones, with increasing arsenic concentration leading to a higher risk of gallstones; however, the risk plateaued when arsenic concentration exceeded 0.62 μg/L. Both the Qgcomp and GWQS indicated that arsenic plays a significant role in increasing the risk of gallstones, whereas zinc plays a significant role in reducing the risk of gallstones. BKMR showed that raising arsenic exposure from the 25th to the 75th percentile increased the risk of gallstones, while raising serum zinc concentration reduced it.

CONCLUSIONS

Higher serum arsenic concentration increases the risk of gallstones, whereas higher zinc concentration may reduce the risk. Effective prevention of gallstones may require further reduction of arsenic exposure and appropriate increases in zinc intake.

Quantitative phase analysis and molecular structure of human gallstones using synchrotron radiation X-ray diffraction and FTIR spectroscopy

Human gallstones are the most common disorder in the biliary system, affecting up to 20 % of the adult population. The formation of gallstones is primarily due to the supersaturating of cholesterol in bile. In order to comprehend gallstone disease in detail, it is necessary to have accurate information about phase identification and molecular structure. Different types of gallstone samples were collected from the Middle East area after surgical operations including; cholesterol, pigment, and mixed gallstones. To estimate the basic information about the stone formation and the pathophysiology of cholelithiasis as well as to classify the collected human gallstones, attenuated total reflection Fourier transform Infrared spectrometry (ATR-FTIR) was used to analyze the different gallstone structures in the wavenumber range from 400 to 4000 cm-1. Calcium bilirubinate was specified by the bands at 1662 cm-1, 1626 cm-1, and 1572 cm-1, while cholesterol rings were designated by the bands at 1464, 1438, 1055, and 1022 cm-1. It can be assumed that all samples consist of mixed gallstones based on the doublets at 1375 cm-1 and 1365 cm-1. The levels of calcium bilirubin and various minerals varied among the analyzed samples, indicating the heterogeneity in their composition and suggesting potential implications for gallstone formation. Based on the quantitative phase analysis using synchrotron radiation X-ray diffraction (SR-XRD), two phases of anhydrous cholesterol as a major content and one phase of monohydrate cholesterols as trace content represent the main components of most of the gallstones. Additional phases of calcium carbonate in the form of calcite, vaterite, aragonite, and bilirubinate were also quantified. According to the outcomes of the FTIR and the SR-XRD measurements, there exists a statistical correlation between the different types of chemical constituents of the gallstones.

Microstructural and Geochemical Characterization of Gallstones: Implication for Biomineralization

Stone formation in the gallbladder is one of the growing health issues reported throughout the world. However, studies on the characteristics of gallstone in the Sri Lankan community are very limited. Detail investigation of gallstone is important for identifying the causative factors and understanding the formation process. The present study aimed to investigate the compositional and microstructural characteristics of gallstone in Sri Lankan patients. Twenty-three patients who were admitted for cholecystectomies were selected for the study. The socio-demographic information was collected from patients using a structured questionnaire. Stones that were removed from surgeries were analyzed by their microstructural and compositional features using Fourier Transformed Infra-Red Spectrometer (FT-IR) and Inductively Coupled Plasma Mass spectroscopy (ICP-MS), Scanning Electron Microscope (SEM), and polarizing microscope. 44% of stones were the mixed type that comprised mainly cholesterol and bilirubinate and followed by pigment type (30%) that mainly contained bilirubinate. The pure cholesterol stones which comprise only cholesterol are the least abundant type of stones. Calcium is the major element found in stones followed by Cu, Mn, Fe, Mg, Zn, and Ni. Higher content of these elements was found in pigment stones compared to the other types. The core and crust regions of stones were enriched with Ca compared to the middle part. Concentric layers that comprise alternating dark and light color bands were observed in the crust, reflecting the compositional variation in bile during the formation of gallstones. The electron microscope images confirmed lightly stacked cholesterol with plate- and needle-like crystals and irregularly arranged clumps of bilirubinate. The Ca-rich core of gallstone confirmed that the Ca-salt precipitation possibly provided a nucleus for the stone formation.

Different Surface Appearances Caused by Unbalanced Mn2+ Accumulation in Gallstones Consisting of Cholesterol and CaCO3 Obtained from a Patient After Cholecystectomy

Gallstones were examined for 58 patients in Jilin, Jilin. It was found that gallstones from only one who suffered from cholecystectomy were composed of 20 spheroidal stones and they rarely exhibited three different types of surface appearances. Six representative powder samples were analyzed for gallstones compositions and Mn²⁺ using X-ray diffraction (XRD)/Infrared (IR) and electron spin resonance (ESR), respectively. The results suggested that all gallstones from this patient were identified by XRD to be gallstones consisting mainly of cholesterol and CaCO₃ (GCCC). They rarely exhibited three different kinds of surface appearances corresponding to different concentration of trace Mn²⁺ in calcite (C_Mn²⁺/C_Cal): 18 dark/light brown spheres with smooth surfaces and C_Mn²⁺/C_Cal = 0-6 μg/g/%, a yellowish-brown huge sphere with a rougher surface and C_Mn²⁺/C_Cal = 30 μg/g/%, and an ashy sphere composed of tens of microspheres with the roughest surface and C_Mn²⁺/C_Cal = 60 μg/g/%. The difference in surface appearance showed significant association with C_Mn²⁺/C_Cal, and its increase made the gallstone's surface change from smooth to rough and to fade in color. The unbalanced and competitive Mn²⁺ accumulation could occur occasionally in individual stones owing to different affinities to Mn²⁺, resulting in the formation of a huge stone and an ashy sphere. These two aberrations caused by higher C_Mn²⁺/C_Cal played an important role in suppressing the crystalline growth of the majority of dark/light brown spheres. GCCC from a patient might have a prominent Mn²⁺ partitioning feature corresponding to different surface appearances.

Preliminary study on the correlation between the trace Mn2+ and the calcite polymorph in gallstones containing calcium carbonate from the northeast China via electron spin resonance

Gallstones containing calcium carbonate (GCCC) from the northeast China were analyzed using X-ray diffraction (XRD), infrared spectroscopy (IR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and electron spin resonance (ESR). The sextet signal arising from the allowed transitions of the trace Mn²⁺ ions in GCCC was found to be ESR-detectable and strong. The XRD technique revealed the crystal habit of calcite in GCCC. Of the three polymorphs of calcium carbonate, no calcite was present as a solitary crystallization form, accompanied by aragonite or vaterite or both. The sextet ESR signal and the (104) main XRD peak at 2θ = ∼29.4° were employed as two probes to explore the relationship between trace Mn²⁺ and calcite. The Mn content can be considered as an indicator of the amount of calcite in GCCC because of the existence of a correlation between Mn²⁺ and calcite. The correlation between Mn²⁺ and calcite, the relation between the levels of Mn²⁺ and the type of gallstones, the structural preference of Mn²⁺ to the calcite polymorph, and the influence of dietary habits on calcite in calcium carbonate gallstones are discussed.

Multi-analyses of gallstones and correlation between their properties with the laboratory results

This study explores the morpho-structure of gallstones (GSs) removed from 36 patients in NW Romania and correlate it with the laboratory results of the patients. GSs were analyzed by SEM-EDS, X-ray diffraction and IR, UV-Vis and X-ray photoelectron spectroscopy. The laboratory studies consisted in hematological, coagulation, biochemistry, immunological and tumor markers tests. The morphological and structural investigations allowed to classify the GS in five different types and to establish their mechanism of formation. Only macroscopic evaluation, SEM microscopy, FTIR and UV-Vis spectroscopy give different easily noticeable information for each GS type. EDS, XPS and XRD diffraction are recommended to distinguish pigment and carbonate stones from the other GS types and a carefully examination is needed to establish the differences between the pure cholesterol, the mixed cholesterol and the composite cholesterol stones, due to the high similarities. The variation of specific markers cannot differentiate the patients with pure cholesterol GS from those with mixed cholesterol and pigment GS and those with mixed cholesterol from those with composite cholesterol stones. Seven laboratory parameters (RDW-CV, MPV, PCT, GLUC-HK, WBC, PT, GPT) are the key indicators for the GS disease and trend to present generally higher values than normal.

Lichens as a spatial record of metal air pollution in the industrialized city of Huelva (SW Spain)

Huelva is a highly industrialized city in SW Spain hosting, among others, a Cu smelter, a phosphate fertilizer plant, a power plant, and oil refineries. This study aims to evaluate metal concentrations in lichens as bioindicators of atmospheric pollution in the impacted urban areas. Xanthoria parietina species from Huelva and nearby villages, as well as reference samples from remote, non-contaminated urban areas, were analyzed for trace elements (V, Cr, Mn, Co, Ni, Cu, Zn, Sr, As, Cd, Sb, Cs, Ba, La, Ce, Pr, Nd, Sm, Er, Tm, Yb, Lu, Pb, Th, U) using Inductively Coupled Plasma-Mass Spectrometry; and for major elements (Ca, K, Mg, P, and S) by Inductively Coupled Plasma-Optical Emission Spectrometry after acid digestion. The metal composition of X. parietina exhibits spatial distribution patterns with extremely elevated concentrations (Co, Ni, Cu, Zn, As, Cd, Sb, Ba, Pb, U, and S) in the surroundings of the industrial estates to <1 km distance. Mean concentrations were significantly lower in the urban areas >1 km from the pollution sources. However, air pollution persists in the urban areas up to 4 km away, as the mean concentrations of Cu, Zn, As, Cd, Sb and S remained considerably elevated in comparison to the reference samples. Though rigorous source apportionment analysis was not the aim of this study, a good positive correlation of our results with metal abundances in ambient particulate matter and in pollution sources points to the Cu smelter as the main source of pollution. Hence, the severe air pollution affecting Huelva and nearby urban areas may be considered a serious health risk to local residents.

Unraveling the impact of chronic exposure to metal pollution through human gallstones

This study aims to explore the impact of chronic metal exposure derived from persistent pollution from mining activity using human gallstones as proxies. The samples were obtained from patients residing in geologically and environmentally contrasting areas in the Province of Huelva, SW Spain, allowing for the evaluation of the regional effect of metal pollution. The study group resides in the Iberian Pyrite Belt characterized by natural and anthropogenic metal pollution from mining activities, whereas the control group resides in the Ossa Morena Zone famous for its natural parks. A total of 68 gallstones were first classified based on their phase composition and structure and subsequently their chemical composition was studied using solution Inductively Coupled Plasma-Mass Spectrometry. The metal concentrations increased in the cholesterol-rich gallstones from pure, to mixed and composite cholesterol stones along with the increasing amount of minor phases, such as bilirubinate, carbonate, and phosphate. These cholesterol stones did not show an evident enrichment tendency. On the contrary, pigment stones, composed of bilirubinate, carbonate, and phosphate phases, were rich in a variety of elements and the regional comparison showed that the pigment stones from the study area were enriched in sulfide-associated metal(loid)s, Mn, Fe, Cu, Zn, Sr, As, Ag, Sb, and Pb with respect to the control group. Inhalation of polluted airborne particulate matter is considered as one of the main exposure routes among the residents of the study area. Additionally, consumption of local water and locally produced food products such as fruit and vegetables and dermal contact may be possible sources of exposure, but no direct connection was observed.

Recent advances in understanding and managing cholesterol gallstones

The high prevalence of cholesterol gallstones, the availability of new information about pathogenesis, and the relevant health costs due to the management of cholelithiasis in both children and adults contribute to a growing interest in this disease. From an epidemiologic point of view, the risk of gallstones has been associated with higher risk of incident ischemic heart disease, total mortality, and disease-specific mortality (including cancer) independently from the presence of traditional risk factors such as body weight, lifestyle, diabetes, and dyslipidemia. This evidence points to the existence of complex pathogenic pathways linking the occurrence of gallstones to altered systemic homeostasis involving multiple organs and dynamics. In fact, the formation of gallstones is secondary to local factors strictly dependent on the gallbladder (that is, impaired smooth muscle function, wall inflammation, and intraluminal mucin accumulation) and bile (that is, supersaturation in cholesterol and precipitation of solid crystals) but also to "extra-gallbladder" features such as gene polymorphism, epigenetic factors, expression and activity of nuclear receptors, hormonal factors (in particular, insulin resistance), multi-level alterations in cholesterol metabolism, altered intestinal motility, and variations in gut microbiota. Of note, the majority of these factors are potentially manageable. Thus, cholelithiasis appears as the expression of systemic unbalances that, besides the classic therapeutic approaches to patients with clinical evidence of symptomatic disease or complications (surgery and, in a small subgroup of subjects, oral litholysis with bile acids), could be managed with tools oriented to primary prevention (changes in diet and lifestyle and pharmacologic prevention in subgroups at high risk), and there could be relevant implications in reducing both prevalence and health costs.

New insights into the metal partitioning in different microphases of human gallstones

Chronic metal exposure, e.g. from metal mining, may cause accumulation of metals in soft and hard tissues, and in developing biomineralizations in the human body. Gallstones are biomineralizations formed in the gallbladder which are able to trap trace elements from the bile. Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) was used to analyze gallstone cross-sections to trace the elemental abundances and correlate them with the principal phases constituting gallstones, namely cholesterol, Ca bilirubinate salts, Ca carbonate, and Ca phosphate. Five different types of gallstones (pure, mixed, and composite cholesterol stones, pigment stone, and carbonate stone) were chosen according to a previous classification based on phase characterization by different spectroscopic and microscopic techniques. These data were combined with bulk solution ICP-MS/OES analyses for total elemental concentrations. The results indicated that cholesterol has a zero capacity to retain elements except for Ca. Hence, pure cholesterol stones contained the lowest bulk metal concentrations, and the metals were found in the scarce carbonate and phosphate phases in these calculi. Calcium and trace element concentrations increased in other types of gallstones along with increasing amount of bilirubinate, carbonates and phosphates; pigment stones being the most enriched in metals. Phosphates were the principal carriers of Ca, P, Na, Mg, Mn, Fe, Pb, and Cd, whereas carbonate phases were enriched in Ca, Mg, Na, and Mn in order of decreasing abundance. Bilirubinate on the other hand was enriched in Ca, Cu, Ag, and Ni. The higher trace metal affinities of bilirubinate and phosphate explain the elevated metal concentrations observed in the pigment stones. These results give new insight to the trace metal behavior in the gallstone formation and the metal accumulation in the human body, validating the possible use of these biomineralizations as a proxy for exposure to metal pollution.