Cyclic Deposition of Calcium Salts During Growth of Cholesterol Gallstones

Some cholesterol gallstones contain darkly pigmented centers or peripheral concentric pigmented bands. We examined the cross-sectional surface of three cholesterol gallstones which contained both central and peripheral pigmented areas with electron-probe microanalysis (EPM) and energy dispersive x-ray microanalysis (EDXA) to determine the elemental composition of the pigmented regions. Linear EPM across the cross-sectional surface of the stones demonstrated that most of the pigmented regions of all three stones had high Ca and P signals; the nonpigmented intervening areas had markedly lower or no detectable Ca and P signals. In two of the three stones, high O signals coincided with the high Ca and P signals suggesting that both calcium bilirubinate and calcium phosphate were present in these pigmented areas. EDXA of the central and peripheral pigmented areas of each stone confirmed the presence of a high Ca signal. Our results demonstrate that in some cholesterol gallstones there is cyclic deposition of calcium bilirubinate and other calcium salts

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2–4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Studies on the Pathogenesis of Pigment Gallstones in Hemolytic Anemia: DESCRIPTION AND CHARACTERISTICS OF A MOUSE MODEL

The pathogenesis of hemolysis-induced gallstones was studied in mice with a hereditary hemolytic disease called normoblastic anemia (genotype nb/nb) and in their normal controls (genotype +/+). Infrared spectroscopy demonstrated that spontaneously formed gallstones from nb/nb mice were nearly identical to stones from patients with chronic hemolysis as the result of sickle cell disease, and both mouse and human stones strikingly resembled synthetic calcium bilirubinate. 57% of 115 nb/nb mice, but none of 109 control mice, developed calcium bilirubinate pigment gallstones (P < 0.001). The incidence of luminal gallstones in nb/nb mice was both sex and age dependent. Female nb/nb mice formed stones twice as frequently as male nb/nb mice (P < 0.001). Before 6 mo of age neither sex developed stones, but thereafter the incidence of stones increased with age. Neither hematocrit, reticulocyte count, nor total plasma bilirubin values, were useful in distinguishing between nb/nb mice with or without gallstones. In gallbladder bile, nb/nb mice with gallstones had higher concentrations of hydrogen ion, total bilirubin, calcium, and bile acids than nb/nb mice without stones. Although total unconjugated bilirubin was similar in both nb/nb groups, the ionized fraction of unconjugated bilirubin was higher in bile from nb/nb mice without stones than those with stones. In nb/nb mice, neutral mucin plugs and pigment concentrations were observed histologically in the glandular crypts of the gallbladder in 33% of nb/nb mice without stones and in 80% of nb/nb mice with luminal stones. This suggested that luminal pigment stone disease in mice with hemolysis may be preceded by microscopic precipitation of calcium bilirubinate in the glandular crypts of the gallbladder. These precipitates may then migrate into the lumen and grow by accretion

Interaction of hemolytic anemia and genotype on hemolysis-induced gallstone formation in mice.

We previously reported that nb/nb mice with hereditary hemolytic anemia spontaneously developed calcium bilirubinate pigment gallstones. To assess the extent to which gallstone formation and bile composition is gene dependent, we transferred the hemolytic process by transplanting bone marrow from nb/nb mice into a nonhemolytic, but histocompatible genotype, W/Wv mice. Hematologic parameters of transplanted W/Wv mice were nearly identical to those of nb/nb mice. Like nb/nb mice, the percentage of transplanted mice with gallstones increased with the duration of the hemolysis and occurred twice as often in female mice as in male mice (37% vs. 19%; p less than 0.05). However, the rate of gallstone formation in transplanted mice was one-third less than that in nb/nb mice (3.6% per month vs. 5.5%; p less than 0.05). Analysis of hepatic bile revealed that (a) marrow-transplanted mice had higher concentrations of unconjugated bilirubin due to hemolysis (p less than 0.05) and of total bile acids determined by the W/Wv genotype (p less than 0.001) than their respective nb/nb counterparts and (b) transplanted mice with stones had a significantly lower proportion of cholic acid (p less than 0.005) and higher proportion of keto-bile acids (p less than 0.005) than transplanted mice without stones, suggesting that the cholic acid concentration may retard stone formation. These data indicate that the hemolytic process is the primary determinant of pigment gallstone formation in these mice and is influenced by the following factors: (a) duration of the hemolytic process, (b) gender, and (c) the genotype that regulates the composition of biliary components like bile acids