Changed Profile of Serum Transferrin Isoforms in Liver Diseases

Chemokines in Primary Liver Cancer

The liver is responsible for extremely important functions in the human body. In the liver’s structure, we distinguish between connective tissue (stroma) and parenchyma, the latter of which is formed from the basic structural and functional units of the liver—hepatocytes. There are many factors, that negatively affect the liver cells, contributing to their damage. This may lead to fibrosis, liver failure and, in consequence, primary liver cancer, which is the sixth most commonly diagnosed malignancy and the fourth leading cause of cancer death worldwide. Chemokines are a large family of secreted proteins. Their main role is to direct the recruitment and migration of cells to sites of inflammation or injury. Some authors suggest that these proteins might play a potential role in the development of many malignancies, including primary liver cancer. The aim of this study was to evaluate and summarize the knowledge regarding liver diseases, especially primary liver cancer (HCC) and the participation of chemokines in the development of this malignancy. Chemokines involved in the initiation of this type of tumor belong mainly to the CC and CXC chemokines. Their significant role in the course of hepatocellular carcinoma proves their usefulness in detecting and monitoring the course and treatment in patients with this disease.

The Serum Profile of Transferrin Isoforms in Pancreatitis

Total transferrin concentration changes in acute-phase reactions. Additionally, the alteration of transferrin glycosylation in inflammations can occur. The aim of this study is to evaluate the effect of pancreatitis on the serum profile of transferrin isoforms. The tested groups consisted of 84 patients with acute pancreatitis and 42 patients with chronic hepatitis. Transferrin isoforms were analyzed by capillary electrophoresis on a MINICAP electrophoretic system (Sebia, France). There was a significant decrease in the concentration of pentasialotransferrin in both acute and chronic pancreatitis, and a significant increase in tetrasialotransferrin in the acute pancreatitis group when compared to the control group. There were no significant changes in transferrin isoforms between the acute and chronic pancreatitis groups, and between the edematous and necrotizing forms of the disease. Considering the etiology of acute pancreatitis, we noticed higher values of bile acids and γ-glutamyltransferase in acute pancreatitis of alcoholic etiology than that in pancreatitis of other etiologies. In conclusion, the alterations in transferrin isoform profile in acute and chronic pancreatitis are not organ specific. Because similar changes were observed in hepatitis, we can conclude that the serum profile of transferrin isoforms is involved in the pathogenesis of the disease.

Changed Profile of Serum Transferrin Isoforms in Primary Biliary Cholangitis

Liver damage affects the synthesis of proteins and glycoproteins, and alters their posttranslational modification, such as glycosylation changing the serum profile of glycoprotein isoforms. The retention of hydrophobic bile acids in the course of cholestatic liver diseases is a major cause of liver damage in primary biliary cholangitis (PBC). The study objective was to determine the serum profile of transferrin isoforms in primary biliary cholangitis and compare it to transferrin isoforms profile in extrahepatic cholestasis. The study was carried out in 76 patients with PBC and 40 healthy blood donors. Transferrin isoforms were analyzed by the capillary electrophoresis method. The mean relative concentrations of disialotransferrin and trisialotransferrin in PBC were significantly lower than those in the healthy subjects (p < 0.001, p = 0.011; respectively). None of the transferrin isoforms changed according to the disease severity evaluated by the Ludwig scoring system. However, the disease stage affected the activity of alkaline phosphatase (ALP) and γ-glutamyl transferase (GGT), and albumin level (p = 0.002; p = 0.013 and p = 0.005, respectively). Our results indicate that serum profile of transferrin isoforms alters primary biliary cholangitis and differs in comparison to transferrin isoforms profile in extrahepatic cholestasis. The decreased concentrations of lower sialylated isoforms of transferrin (low percentage share in total transferrin level) are not associated with the histological stage of disease.

Pediatric Liver Disease Patients and Secondary Glycosylation Abnormalities

Background: Isoelectric focusing (IEF) of serum transferrin (Tf) is still the method of choice for diagnosis of congenital disorders of glycosylation (CDG). An abnormal glycosylation is also a known phenomenon in adult liver disease patients. The aim of this study was to characterize glycosylation disturbances in pediatric patients with primary liver disease. However, there are no reports of this phenomenon in children. Materials and Methods: Between 1995 and 2019, circa 2,000 serum Tf isoform analyses have been performed in children with primary liver diseases; some of them underwent subsequent analyses. We enrolled in this study 19 patients who developed an acute liver injury (ALI)/failure (ALF) or exhibited a chronic liver disease (CLD) and were evaluated and listed for liver transplantation (LTx) or had just undergone this procedure, and secondary abnormal serum Tf isoform profile. Results: Among 12 patients with ALI/ALF, 10 had an increased percentage of asialo-, monosialo-, and disialo-Tf isoforms. All patients with CLD had an increased percentage of asialo- and monosialo-Tf isoform. Two patients diagnosed with recurrent ALF had very specific serum Tf profile with a huge increase in the asialo- and monosialo-Tf isoform. On follow-up analyses (available in some patients), serum Tf IEF profile normalized in parallel to normalization of liver function tests, spontaneously or during treatment, including glucocorticosteroids in AIH, LTx in CLD. Conclusions: All pediatric patients with primary liver disease had increased asialo-Tf as well as monosialo-Tf isoforms. None of them had elevated percentage of trisialo-Tf isoform.

The Profile of Serum Transferrin Isoforms in Rheumatoid Arthritis

INTRODUCTION

Transferrin, a microheterogeneous iron-transporting N-glycoprotein, is an optimal model for the analysis of the glycosylation profile in rheumatoid arthritis (RA). The aim of this study was to assess the transferrin isoforms profile in RA patients at the time of diagnosis and then look into their associations with disease activity.

METHODS

Serum samples were collected from 48 patients with RA. The patients were males (6) and females (42) (age range: 33-85 years). Control group consisted of 30 healthy volunteers. Transferrin isoforms were analysed by capillary electrophoresis on MINICAP electrophoretic system.

RESULTS

There was a significant decrease in the relative concentrations of trisialo- (mean ± SD; 2.130 ± 1.112) and pentasialotransferrin (13.562 ± 3.088), and significant increase in tetrasialotransferrin (83.640 ± 3.165) in RA patients when compared to the control group (3.615 ± 1.156; 76.840 ± 5.621; 18.610 ± 6.027, respectively) (U Mann-Whitney test: p < 0.001 for all comparisons). There were no significant changes in the disialotransferrin concentrations in RA patients. Trisialotransferrin concentration correlated with RA activity expressed as DAS 28 in RA patients (p < 0.001). The low trisialotransferrin concentration was also associated with high platelet count and high ESR (p < 0.001 for both). Disialo-, tetrasialo- and pentasialotransferrin concentrations did not correlate with DAS 28.

CONCLUSIONS

In patients with RA the serum profile of transferrin isoforms is altered. We predict that the levels of trisialylated isoforms of transferrin will serve as a useful biochemical marker of the RA activity.

Low-molecular-mass iron complexes in blood plasma of iron-deficient pigs do not originate directly from nutrient iron

Nutrient iron entering the blood binds transferrin (TFN)d, which delivers iron to cells in the body. In healthy individuals, ∼30% of TFN is iron-bound while the remainder is unbound (apo-TFN). TFN saturates the plasma of individuals with iron-overload diseases such as hereditary hemochromatosis, prompting release of a poorly-defined low-molecular-mass (LMM) iron species called non-transferrin-bound iron (NTBI). An experiment was devised to directly detect NTBI in plasma of iron-deficient pigs and to assess the role of the liver which is known to bind NTBI. Catheters were surgically installed in the portal vein (PV) and either the caudal vena cava or the cranial vena cava. After the animals recovered, 57Fe II ascorbate was injected into the stomach via a feeding tube. Blood was removed through the catheters before and after injection; plasma became 57Fe-enriched after injection. 57Fe-enriched plasma was passed through a 10 kDa cutoff membrane and the flow-through solution (FTS) was subjected to size-exclusion liquid chromatography (LC). The eluent flowed into an ICP-MS where 56Fe and 57Fe were detected. Low-intensity iron peaks with masses of 400-1600 Da were observed, but none became enriched in 57Fe after injection. Rather, the injected 57Fe bound to apo-TFN. Viewed naively, this implies that nutrient-derived 57Fe in healthy mammals passes from the intestines to apo-TFN without first entering the blood as a LMM intermediate. In this case, nutrient iron exported from intestinal enterocytes of healthy individuals may quickly bind apo-TFN such that LMM iron species do not accumulate in blood plasma. Some 57Fe from the FTS may have adsorbed onto the column. In any event, the LMM iron species in plasma that eluted from the column must have originated from iron stored within the body, perhaps in macrophages - not directly from nutrient iron absorption. The liver absorbed and released LMM iron species, but the effect was modest, consistent with its role as a dynamic iron buffer. Passage through the liver also altered the distribution of different forms of TFN present in the PV.

Serum profile of transferrin isoforms in rheumatoid arthritis treated with biological drugs

BACKGROUND

In the chronic inflammation process in the course of rheumatoid arthritis (RA), many alterations in the expression of plasma proteins, as well as their posttranslational modifications (including glycosylation) can occur. Taking into account the disturbances in protein glycosylation and the emerging new treatment regimens, the aim of this study was to assess the serum profile of transferrin isoforms in RA patients treated with biological drugs.

METHODS

The study included 20 patients (16 females and 4 males; mean age: 53.4 years; range: 24-67) with rheumatoid arthritis treated with rituximab. Serum samples were taken 3 times: before and 3 and 6 months during treatment. The isoforms of transferrin were separated by capillary electrophoresis (MINICAP electrophoretic system, Sebia, France) into five major fractions: asialo-, disialo-, trisialo-, tetrasialo- and pentasialotransferrin. The results were calculated as relative concentrations of each fraction.

RESULTS

The median trisialotransferrin relative concentrations after 3 and 6 months treatment (4.40% and 4.10%, respectively) were significantly higher (p = 0.013, p = 0.009, respectively) than before treatment (3.50%). The levels of serum pentasialotransferrin were also increased 3 and 6 months following treatment (16.5% and 17.7%, p = 0.005 and p = 0.006, respectively) as compared to those before therapy (14.5%), while tetrasialotransferrin concentrations were lower (80.3% and 78.4%, p = 0.009 and p = 0.008, respectively) than before treatment (81.5%). Trisialotransferrin relative concentration correlated with Hb (p = 0.019), whereas pentasialotransferrin with PLT (p = 0.036) after treatment.

CONCLUSIONS

This study indicates that treatment with rituximab of RA patients alters the serum profile of transferrin isoforms. Tri-, tetra- and pentasialotransferrin relative concentrations measurements can be a useful tool to monitor therapy.