Maria Warwas

Ischemia-modified albumin level in type 2 diabetes mellitus - Preliminary report.

Aim: The main goal of the present study was the evaluation of ischemia-modified albumin (IMA) in patients with type 2 diabetes mellitus and estimation of its connection with vascular complications, glycemic control, hypertension, dyslipidemia and obesity. Methods: In 76 diabetic patients and 25 control subjects, a plasma level of IMA by manually performed, spectrophotometric Co(II)-albumin binding assay was determined. Other parameters such as glucose, fructosamine, HbA1c, total cholesterol and its fractions (HDL, LDL), triglicerydes were estimated by routine methods. Results: Diabetic patients had significantly higher level of IMA in comparison with control subjects. There were not significant differences between groups with various states of vascular complications although the lowest concentration of IMA was observed in patients with microangiopathy. Patients with poor glycemic control had higher IMA level in comparison with these with good glycemic control. Significant correlation was observed between IMA and HbA1c. Among the risk factors, only blood pressure and LDL showed a weak relationship with IMA level. Conclusions: Our results revealed, for the first time, higher level of IMA in diabetic patients which confirms that it may be of non-cardiac origin. We can suggest that the albumin molecule in plasma of diabetic patients is modified in the chronic hypoxia conditions provoked mainly by hyperglycemia and oxidative stress in diabetes.

Concentration of leukocyte elastase in plasma and polymorphonuclear neutrophil extracts in type 2 diabetes.

Abstract The concentration of leukocyte elastase/α1-proteinase inhibitor complexes in plasma and polymorphonuclear neutrophil extracts, and plasma trypsin inhibitory capacity were determined in 88 patients with type 2 diabetes and 47 control subjects. Higher values of these variables were found in patients as compared to controls (p < 0.001). The concentration of elastase was higher in obese patients than in lean ones (p < 0.05 for plasma, p < 0.01 for polymorphonuclear leukocytes). Only leukocyte elastase levels were significantly higher in the group with both micro- and macroangiopathy in comparison to the group with microangiopathy (p < 0.01) or macroangiopathy (p < 0.05) alone. Poor short-term glycaemic control was associated with higher elastase concentration in plasma and neutrophils (p < 0.05). The present study demonstrates that measurements of plasma polymorphonuclear neutrophil elastase level can be considered as a marker of development of diabetic angiopathy.

Plasma glycooxidation protein products in type 2 diabetic patients with nephropathy

In diabetes mellitus, hyperglycaemia accelerates non‐enzymatic glycation and oxidative stress leading to damage of macromolecules, among others proteins. This manifests in the increased levels of advanced glycation end products (AGE) and advanced oxidation protein products (AOPP).

Markers of oxidative protein damage in plasma and urine of type 2 diabetic patients

Abstract This study aims to measure selected markers of oxidative protein damage (OPD) in patients with type 2 diabetes mellitus (T2DM) in order to estimate their utility as indicators of oxidative stress (OS) and to search for possible associations between them. The concentrations of advanced oxidation protein products (AOPP) and total sulphydryl (TSH) and reactive carbonyl (RCO) groups are measured in the plasma (P) and urine (U) of 60 patients and 22 controls using spectrophotometric methods. Significantly higher plasma concentrations of AOPP (P<0.001), RCO groups (P<0.01) and their P/U indexes (P<0.001) as well as urinary levels of the RCO and TSH groups (P<0.001) were observed in the diabetic patients compared with the controls. In contrast, the plasma levels and P/U index of the TSH groups were significantly lower (P<0.001). A progressive increase in AOPP (plasma, urine and P/U index) in the course of albuminuria was noted, but significant differences among the subgroups of patients (with normoalbuminuria, microalbuminuria and macroalbuminuria) were found only in plasma. Plasma levels of all the measured parameters of OPD showed significant changes in T2DM patients compared with the control group. The largest increase was observed for AOPP. As the urinary AOPP concentration was not significantly different to that of the controls, it cannot be recommended as a marker of oxidative stress for monitoring the development of diabetic nephropathy. The P/U indexes did not provide any more information than the plasma concentrations of the studied markers.

Urinary cystatin C as a biomarker of renal tubular injury

Cystatin C (cysC) is an endogenous cysteine peptidase (proteinase) inhibitor that has been intensively investigated as a biomarker of kidney function for many years. It is freely filtered at the kidney glomerulus because of its small size and lack of cysC binding protein. A very small amount of cysC appears in the urine because of its total reabsorption in the proximal tubule and lack of secretion. Since 1985 cystatin C has been studied mainly in serum/plasma as an alternative biomarker to serum creatinine to estimate GFR. In this review we present the recent discoveries concerning urinary cystatin C determination as a tubular injury biomarker.

Clearance of chicken cystatin from the rat circulation

Chicken cystatin (mixed form) was prepared from egg white. Radioactively labeled preparations were administered intravenously to rats. 125I-cystatin disappeared from the rat circulation with a half-life of approximately 73 min. The radiolabeled inhibitor was rapidly taken up by the kidneys. Percoll density gradient analysis showed that it was incorporated into lysosomes. Within 24 hr after the injection of 125I-cystatin, 25% of the administered radioactivity was recovered in the urine, but only 2% was in the protein-bound form.

Activities of Neutrophil Membrane-bound Proteases in Type 2 Diabetic Patients

BACKGROUND AND AIMS Hyperglycemia and oxidative stress in type 2 diabetes (T2DM) provoke neutrophil overstimulation and the release and/or translocation of proteases from granules to the cell surface. Although the expression of neutrophil membrane-bound elastase (MLE) is well documented, the presence of the membrane-bound form of cathepsin B (MCB) is unknown. The aim of our study was to evaluate the neutrophil MLE and MCB activities in T2DM patients and their associations with the metabolic and clinical parameters of the disease. METHODS Neutrophils were obtained from 47 T2DM patients and 20 control subjects. The activities of MLE and MCB and the intracellular activities of the examined proteases (ILE and ICB, respectively) were measured using fluorometric substrates. Additionally, the percentage equivalents of the activities, namely, MLEtot/ILEtot and MCBtot/ICBtot, were calculated. The susceptibility to inhibitors of both forms of the studied proteases was also determined. RESULTS A significant increase in the activities of MLE, MCB, ILE, and ICB was found in neutrophils from T2DM patients compared with the control group. The percentage equivalent (contribution of the total membrane-bound activities to the total intracellular activities) was also higher. A partial resistance of the membrane-bound forms toward their inhibitors was revealed. Higher activities of both the membrane-bound and the intracellular proteases were also observed in patients with poor glycemic and metabolic control. The differences between subgroups with different therapeutic schemes were also revealed. CONCLUSIONS The pathophysiological implications of the neutrophil membrane-bound forms of leukocyte elastase and cathepsin B are of great importance in the development of T2DM and its complications.

Influence of aminoglycoside antibiotics on chicken cystatin binding to renal brush-border membranes.

Drug‐induced kidney injury is a serious adverse event which needs to be monitored during aminoglycoside therapy. Urine cystatin C is considered an early and sensitive marker of nephrotoxicity. Cystatin C, a low‐molecular‐weight serum protein, and basic drugs have a common transport system expressed in the apical membrane of renal proximal tubular cells. The aim of this study was to investigate whether aminoglycoside antibiotics influenced cystatin C binding to the renal brush‐border membrane.

Picolinic Acid in Patients with Chronic Hepatitis C Infection: A Preliminary Report

Macrophage activation seems to be a feature of chronic liver diseases. Picolinic acid (PA) as a macrophage secondary signal causes the activation of interferon-gamma- (IFN-γ-) prime macrophage and triggers cytokine-driven inflammatory reactions. The rationale for seeking increased PA formation in chronic viral hepatitis is based on the involvement of activated macrophages in chronic viral hepatitis-associated inflammation. The aim of this study was to determine serum PA levels in patients with chronic hepatitis C infection, taking into account the presence of diabetes. We assessed PA and high-sensitivity C-reactive protein (hsCRP) as a marker of inflammation in 51 patients with chronic hepatitis C infection (CHC), both with and without diabetes and 40 controls. Compared with the controls, the patients with CHC showed a significant increase in plasma concentrations of PA and hsCRP (P < 0.01 and P < 0.05, resp.). The values of PA and hsCRP were more elevated in patients with diabetes than without diabetes (both P < 0.01). The positive relationships were between PA and hsCRP levels (P < 0.05) and the presence of diabetes (P < 0.001). We documented that significant elevation in serum PA levels is associated with diabetes prevalence and increased inflammatory response reflected in hsCRP levels in CHC patients.

Glycated albumin as a marker of glycemia in diabetes and its vascular complications

Effective glycemic control is very important to prevent the onset and the progression of chronic complications in diabetic patients. It is known that glycation of various proteins is increased in diabetic patients compared with non-diabetics. Among these glycated proteins, glycated hemoglobin (HbA1c) is commonly used as a gold standard index of glycemic control in the clinical setting. However, it can be unreliable in conditions affecting the lifespan of erythrocytes (120 days) as well as in the clinical state in which glycemic control alleviates or deteriorates in a short period. By overcoming the shortcomings of HbA1c, glycated albumin (GA) has gained interest as a useful index for an intermediate glycation period (2 weeks) and pathogenic protein. After giving a brief overview of the key role of HbA1c as a long-term glycemic marker, this review focuses on (a) glycation of human albumin and its main properties, (b) methods of GA determination, (c) the recent clinical status of GA as a glycemic index in diabetic patients and its association with vascular complications. Finally, conditions with a possible inaccurate GA level are also mentioned.