Liver copper content in patients with inflammatory bowel disease and associated liver disorders

Copper impairs the intestinal barrier integrity in Wilson disease

In Wilson disease (WD), liver copper (Cu) excess, caused by mutations in the ATPase Cu transporting beta (ATP7B), has been extensively studied. In contrast, in the gastrointestinal tract, responsible for dietary Cu uptake, ATP7B malfunction is poorly explored. We therefore investigated gut biopsies from WD patients and compared intestines from two rodent WD models and from human ATP7B knock-out intestinal cells to their respective wild-type controls. We observed gastrointestinal (GI) inflammation in patients, rats and mice lacking ATP7B. Mitochondrial alterations and increased intestinal leakage were observed in WD rats, Atp7b-/- mice and human ATP7B KO Caco-2 cells. Proteome analyses of intestinal WD homogenates revealed profound alterations of energy and lipid metabolism. The intestinal damage in WD animals and human ATP7B KO cells did not correlate with absolute Cu elevations, but likely reflects intracellular Cu mislocalization. Importantly, Cu depletion by the high-affinity Cu chelator methanobactin (MB) restored enterocyte mitochondria, epithelial integrity, and resolved gut inflammation in WD rats and human WD enterocytes, plausibly via autophagy-related mechanisms. Thus, we report here before largely unrecognized intestinal damage in WD, occurring early on and comprising metabolic and structural tissue damage, mitochondrial dysfunction, and compromised intestinal barrier integrity and inflammation, that can be resolved by high-affinity Cu chelation treatment.

Identification of cuproptosis-associated subtypes and signature genes for diagnosis and risk prediction of Ulcerative colitis based on machine learning

Background

Ulcerative colitis (UC) is a chronic and debilitating inflammatory bowel disease that impairs quality of life. Cuproptosis, a recently discovered form of cell death, has been linked to many inflammatory diseases, including UC. This study aimed to examine the biological and clinical significance of cuproptosis-related genes in UC.

Methods

Three gene expression profiles of UC were obtained from the Gene Expression Omnibus (GEO) database to form the combined dataset. Differential analysis was performed based on the combined dataset to identify differentially expressed genes, which were intersected with cuproptosis-related genes to obtain differentially expressed cuproptosis-related genes (DECRGs). Machine learning was conducted based on DECRGs to identify signature genes. The prediction model of UC was established using signature genes, and the molecular subtypes related to cuproptosis of UC were identified. Functional enrichment analysis and immune infiltration analysis were used to evaluate the biological characteristics and immune infiltration landscape of signature genes and molecular subtypes.

Results

Seven signature genes (ABCB1, AQP1, BACE1, CA3, COX5A, DAPK2, and LDHD) were identified through the machine learning algorithms, and the nomogram built from these genes had excellent predictive performance. The 298 UC samples were divided into two subtypes through consensus cluster analysis. The results of the functional enrichment analysis and immune infiltration analysis revealed significant differences in gene expression patterns, biological functions, and enrichment pathways between the cuproptosis-related molecular subtypes of UC. The immune infiltration analysis also showed that the immune cell infiltration in cluster A was significantly higher than that of cluster B, and six of the characteristic genes (excluding BACE1) had higher expression levels in subtype B than in subtype A.

Conclusions

This study identified several promising signature genes and developed a nomogram with strong predictive capabilities. The identification of distinct subtypes of UC enhances our current understanding of UC's underlying pathogenesis and provides a foundation for personalized diagnosis and treatment in the future.

Comprehensive analysis of cuproptosis-related genes in immune infiltration and diagnosis in ulcerative colitis

Objectives

Cuproptosis is a recently discovered form of programmed cell death; however, its role in ulcerative colitis (UC) remains a void.

Methods

Three gene expression profiles were acquired from the GEO database. Subsequently, the single sample gene set enrichment analysis (ssGSEA) was performed to identify the immune infiltration characteristics of UC. Correlation analysis between cuproptosis and immune infiltration was further conducted, and the cuproptosis-related genes were applied to construct a UC diagnostic model. Subsequently, analysis results of microarray data were experimentally validated by DSS-induced colitis in mice. Finally, therapeutic agents for the cuproptosis-related genes were screened owing to the gaping field of therapeutic agents on cuproptosis.

Results

Three gene expression profiles with 343 samples (290 UC and 53 healthy samples) were included. Immune infiltration revealed that UC patients had a higher level of DCs, B cells, CD8⁺ T cells, iDCs, Macrophages, neutrophils, pDCs, T helper cells, Tfh, Th1 cells, Th2 cells, TIL and Treg than normal subjects. Moreover, almost all cuproptosis-related genes were significantly negatively associated with immune infiltration in UC patients. The risk prediction model based on cuproptosis-related genes showed an excellent discrimination for UC. Animal experiments revealed significant alterations in genes essential for cuproptosis between DSS-induced colitis mice and healthy controls, providing experimental validation for the analysis results of microarray data. Further analysis revealed that latamoxef, vitinoin, clomipramine, chlorzoxazone, glibenclamide, pyruvic acid, clindamycin, medrysone, caspan, and flavin adenine dinucleotide might be the target agents for cuproptosis-related genes.

Conclusions

In conclusion, cuproptosis was significantly associated with immune infiltration in UC, and the cuproptosis-related genes showed an excellent discrimination for UC.

Serum copper, ceruloplasmin and 24-h urine copper evaluations in celiac patients

The aim of the study is to evaluate the serum copper, ceruloplasmin and 24-h urine copper levels in celiac patients. Serum copper, ceruloplasmin and 24-h urine measurements were evaluated in patients with celiac (n = 32), Crohn's (n = 25), Wilson's (n = 11) and in a healthy group (n = 35). Serum and 24-h urine zinc levels, AST, ALT, BUN, creatinine, iron, hemoglobin, hematocrit, lymphocyte, sedimentation and CRP levels were also measured. Results were evaluated statistically and significance was accepted as meaningful if P < 0.05. In celiacs, levels of urine copper were high (52 +/- 29 microg/day, P < 0.000) but serum copper was the same as in controls (105 +/- 16 microg/dl, P < 0.158). High urinary copper of celiacs were coming out in women (56 +/- 30 microg/day) and in man (33 +/- 17 microg/day, P < 0.115). Most celiacs were female (P < 0.001). Serum copper and ceruloplasmin levels in all groups were higher in women than in men and this was meaningful for serum copper in the control group (P < 0.045) and for ceruloplasmin in Crohn's (P < 0.055) and control groups (P < 0.031). Serum (70 +/- 14 microg/dl, P < 0.000) and urine zinc levels (25 +/- 15 microg/dl, P < 0.039) of celiacs were low. Ceruloplasmin levels were higher in celiacs (337 +/- 64 U/1) and Crohn's patients (366 +/- 47 U/l, P < 0.000). Correlations observed in the groups of celiac (P < 0.029) and Crohn's (P < 0.024), celiac and Wilson's (P < 0.001) and Crohn's and Wilson's (P < 0.001) between the ceruloplasmin and 24-h urine copper parameters. AST and ALT levels were higher in celiac and Wilson's patients than in Crohn's patients and controls. Mean CRP levels were significantly higher in Crohn's than others. Lymphocyte counts were meaningfully higher in celiacs. Statistically, while mean iron, hemoglobulin and hematocrit levels of celiac and Crohn groups were meaningfully lower than the normal and Wilson's group, it was similar in Wilson's and the control group. Serum copper (85 +/- 26 microg/dl, P < 0.158) and ceruloplasmin (219 +/- 83 U/l, P < 0.001) levels were low and 24-h urine copper levels were high (415 +/- 346 microg/day) in Wilson's group. Increased urinary loss may be another cause of copper deficiency in female celiacs besides malabsorption and this topic needs more investigation. Increased urinary copper levels in celiac women should not always be regarded as a diagnosis of Wilson's disease.

Early biochemical and histological changes in rats exposed to a single injection of thioacetamide

Liver injury was induced by one subcutaneous administration of thioacetamide (200 mg/kg b.wt.) and studied 24 and 48 hrs later. Levels of aspartate aminotransferase (ASAT) and alanine aminotransferase (ALAT) increased after 24 and 48 hrs. The lysosomal enzymes beta-hexosaminidase (beta-NAG) and beta-glucuronidase (beta-GLU) increased significantly after 24 hrs, while the level of beta-GLU returned to normal after 48 hrs, but the activity of beta-NAG remained significantly high even after 48 hrs. Histopathological examination showed necrotic hepatocytes around the central vein with infiltration of macrophages, neutrophils and eosinophils. The plasma zinc level decreased after 24 hrs and returned to normal after 48 hrs. Liver zinc content increased simultaneously at 24 hrs, returning to normal after 48 hrs. No alterations of plasma copper were observed after 24 and 48 hrs. Copper content of the liver increased significantly after 24 and 48 hrs. The present study thus shows that one dose of thioacetamide results in profound liver injury and supplementation of zinc prior to and simultaneously with thioacetamide normalized plasma zinc, increased liver zinc content and reduced the increase of beta-NAG, but did not influence the histological changes.

Abnormalities in tests of copper metabolism in primary sclerosing cholangitis

Primary sclerosing cholangitis is a chronic, cholestatic syndrome characterized by fibrosing inflammation of the bile ducts that may lead to cirrhosis and death from liver failure. Previous reports have suggested abnormal hepatic copper metabolism in this disease. Therefore, in 70 patients, we prospectively determined the levels of hepatic copper, serum copper, and serum ceruloplasmin, and the rate of urinary copper excretion to assess the diagnostic and prognostic usefulness of these tests. Virtually all patients had at least one abnormal copper test. Hepatic copper levels were elevated in 87% of patients [292 +/- 38 micrograms/g dry wt (mean +/- SE)] and 24-h urinary copper levels in 64% of patients [135 +/- 15 micrograms/24 h (mean +/- SE)] to values comparable to those seen in Wilson's disease or primary biliary cirrhosis. In advanced histologic stages of primary sclerosing cholangitis, progressively higher mean levels of hepatic and urinary copper were found. In the liver, mean copper content (in micrograms per gram dry weight) in disease stages I and II was 147 +/- 36 (mean +/- SE); in stage III (fibrosis), 302 +/- 68; and in stage IV (cirrhosis), 379 +/- 69. In the urine, mean copper excretion (in micrograms per 24 h) in stages I and II was 72 +/- 14 (mean +/- SE); in stage III, 100 +/- 14; and in stage IV, 207 +/- 30. Higher hepatic and urinary copper levels at initial evaluation were associated with decreased survival during a median follow-up period of 2.6 yr: patients with hepatic copper greater than 250 micrograms/g dry wt and urinary copper excretion greater than 200 micrograms/24 h at initial evaluation had an 18-mo survival of less than 60%. We conclude that abnormal copper metabolism is a universal feature of primary sclerosing cholangitis, that hepatic copper accumulates and urinary copper excretion increases as the disease progresses, and that the hepatic copper concentration and the 24-h urinary copper determination are useful prognostic indicators in this disease.

Serum selenium levels in liver diseases

A possible pathogenetic role of selenium deficiency in alcoholic cirrhosis of the liver has previously been discussed. In the present study serum selenium was analyzed in 5 groups of liver diseases. The method used for selenium determination was electrothermal atomic absorption, after thermal stabilization of selenium compounds by addition of nickel nitrate. The selenium level of a reference group of healthy Norwegian adults (n = 40) was 1.53 +/- 0.25 mumol/l. The serum concentrations of selenium in patients suffering from alcoholic cirrhosis, chronic active hepatitis and chronic persistent hepatitis were lowered to 40-80 per cent of those of the reference group. In alcoholic cirrhosis and chronic active hepatitis the decreased serum selenium concentrations were significantly correlated to decreased levels of albumin and prealbumin.

Liver attenuation values at computed tomography related to liver copper content

Forty-three patients were examined with computed tomography of the liver and liver biopsies with measurement of hepatic copper content. All recorded liver attenuation values were within normal range, even in patients with markedly elevated hepatic copper content. No statistically significant correlation between the liver attenuation values and the copper concentrations in liver tissue was demonstrated. At present, therefore, computed tomography has no place in monitoring the development of copper accumulation.

Morphologic features of chronic hepatitis associated with primary sclerosing cholangitis and chronic ulcerative colitis

Histologic, ultrastructural, chemical, and statistical methods were used to study liver biopsy and autopsy specimens from 43 patients who had primary sclerosing cholangitis (PSC), with or without chronic ulcerative colitis (CUC), and from 19 patients who had CUC without PSC. In all study groups, essentially the same abnormalities were found in the hepatic parenchyma outside the major bile ducts, although nondiagnostic tissue samples were observed also. Specimens from patients with extrahepatic PSC were indistinguishable from those patients with combined extra- and intrahepatic PSC. Common findings included periductal fibrosis and inflammation, portal edema and fibrosis, focal proliferation of bile ducts and ductules, focal bile duct obliteration and loss of bile ducts, copper deposition, and cholestasis. Proliferation of bile ducts in some portal tracts and obliteration or absence of bile duct in others were the most characteristic changes. In most specimens, inflammatory changes appeared mild, yet biliary cirrhosis had developed in 34% of the patients. Specimens from patients with PSC, with or without CUC, more often contained bile and strikingly increased stainable copper (Grades 2 and 3) than did specimens from patients with CUC without PSC. Hepatic copper contents, measured by atomic absorption spectrophotometry, also were higher in specimens from patients with PSC. Study of PCS specimens by transmission electron microscopy and by energy-dispersive X-ray microanalysis revealed that most copper was sequestered in lipolysosomes. The recognition of strikingly similar morphologic features in many liver specimens from patients with either PSC or CUC or both suggests that the causes of these conditions are closely related.

Sclerosing cholangitis in ulcerative colitis

In a 5-year period 48 (14%) of 336 patients with ulcerative colitis were found to have hepatobiliary disease. The bile ducts were examined in 35 of these patients, and optimal visualization of both intra- and extra-hepatic bile ducts was obtained in 26. Duct changes compatible with sclerosing cholangitis were found in 14 patients. This finding of sclerosing cholangitis in 4% of all patients admitted with ulcerative colitis by far exceeds previous estimations on the incidence of sclerosing cholangitis in ulcerative colitis. The entire colon was usually affected, and the symptoms of the bowel disease were most often mild or moderate. The age at the onset of the colitis was usually below 20 years in patients with combined ulcerative colitis and hepatobiliary disease. In most patients the hepatobiliary disease gave no symptoms. Biochemical data and the histological findings in the liver biopsies did not distinguish between patients with hepatobiliary disease with and without sclerosing cholangitis. Our follow-up study has so far shown that most patients with sclerosing cholangitis remain asymptomatic for a considerable period of time.