Agnieszka Piwowar

Cell oxidant stress delivery and cell dysfunction onset in type 2 diabetes

Most known pathways of diabetic complications involve oxidative stress. The mitochondria electron transport chain is a significant source of reactive oxygen species (ROS) in insulin secretory cells, insulin peripheral sensitive cells and endothelial cells. Elevated intracellular glucose level induces tricarboxylic acid cycle electron donor overproduction and mitochondrial proton gradient increase leading to an increase in electron transporter lifetime. Subsequently, the electrons leaked combine with respiratory oxygen (O(2)) resulting in superoxide anion ((•)O(2)(-)) production. Advanced glycation end products derive ROS via interaction with their receptors. Elevated diacylglycerol and ROS activate the protein kinase C pathway which, in turn, activates NADPH oxidases. A vicious circle of pathway derived ROS installs. Pathologic pathways induced ROS are activated and persistent though glycemia returns to normal due to hyperglycemia memory. Endothelial nitric oxide synthase may produce both superoxide anion ((•)O(2)(-)) and nitric oxide (NO) leading to peroxynitrite ((•)ONOO(-)) generation. Homocysteine is also implicated in oxidative stress pathogenesis. In this paper we have highlighted the pathologic mechanisms of ROS on atherosclerosis, renal dysfunction, retina dysfunction and nerve dysfunction in type 2 diabetes. Cell oxidant stress delivery have pivotal role in cell dysfunction onset and progression of angiopathies but an early introduction of good glycemic control may protect cells more efficiently than antioxidants.

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.

Proteins from the 18 glycosyl hydrolase family are associated with kidney dysfunction in patients with diabetes type 2

Abstract Objectives: To investigate chitotriosidase (CHIT1) activity and chitinase-3-like protein 1 (YKL-40) concentration in plasma of type 2 diabetic patients and evaluate their relationship with kidney dysfunction. Materials and methods: 94 diabetic subjects and 33 controls were enrolled in the study. Plasma CHIT1 activity and YKL-40 concentration were measured along with routine laboratory parameters. Results: Levels of CHIT1 and YKL-40 in plasma of type 2 diabetic patients increased progressively with the degree of albuminuria. CHIT1 discriminated normoalbuminuric subjects from those with abnormal albuminuria better than YKL-40. Conclusions: CHIT1represent a supportive biomarker connected with development of diabetic vascular complications, especially kidney dysfunction.

Neutrophils as a Source of Chitinases and Chitinase-Like Proteins in Type 2 Diabetes

Purpose The pathophysiological role of human chitinases and chitinase-like proteins (CLPs) is not fully understood. We aimed to determine the levels of neutrophil-derived chitotriosidase (CHIT1), acidic mammalian chitinase (AMCase) and chitinase 3-like protein 1 (YKL-40) in patients with type 2 diabetes (T2D) and verify their association with metabolic and clinical conditions of these patients. Methods Neutrophils were obtained from the whole blood by gradient density centrifugation from 94 T2D patients and 40 control subjects. The activities of CHIT1 and AMCase as well as leukocyte elastase (LE) were measured fluorometrically and concentration of YKL-40 immunoenzymatically. Also, routine laboratory parameters in serum/plasma were determined by standard methods. Results The levels of all three examined proteins were about 2-times higher in diabetic patients in comparison to control subjects. They were significantly correlated with the activity of LE and increased progressively across tertiles of LE activity. Moreover, the activities of CHIT1 and AMCase were significantly correlated with each other. Metabolic compensation of diabetes did not influence the levels of these proteins. In the subgroup of patients with inflammatory evidence only YKL-40 concentration was significantly higher compared to those without inflammation. The highest levels of all three proteins were observed in patients with macroangiopathies. Insulin therapy was associated with lower levels of examined proteins. Conclusions We revealed that neutrophils may be an important source of the increased levels of chitinases and CLPs in T2D, and these proteins may participate in inflammatory mechanisms in the course of the disease and consequent development of diabetic angiopathies.

Changes in glycosylation of human blood plasma chitotriosidase in patients with type 2 diabetes

Human blood plasma chitotriosidase (CHIT1) is a glycoprotein with chitinolytic activity with not fully elucidated biological function. Its increased level is observed in type 2 diabetes mellitus (T2DM) and is associated with development of diabetic complications. The CHIT1 glycosylation profile and degree is still poorly studied and never investigated in T2DM. Therefore the aim of the present study was to examine the association between glycosylation profile and degree and diabetes with accompanying nephropathy. In blood plasma of 28 patients with T2DM and 11 healthy subjects the CHIT1 concentration and specific activity were examined. The profile and degree of CHIT1 glycosylation were determined by lectin-ELISA using lectins specific to O-glycans (Jacalin, MPL, VVL) and sialo-specific SNA and MAA. We revealed that both concentration and specific activity of CHIT1 significantly increased in T2DM, especially in nephropathy with elevated albuminuria. The relative reactivities with lectins, except Jacalin, decreased progressively with T2DM occurrence and albuminuria progression. The most significant differences were observed between control vs. albuminuric group (Micro and Macro). It is also possible that the observed differences in immunoblotting pattern in molecular masses of CHIT1 bands between T2DM patients and healthy subjects may be caused by the differences in degree of CHIT1 glycosylation. The analysis of CHIT1 glycosylation status and the determination of CHIT1 concentration together with its enzymatic activity in blood plasma might constitute additional valuable diagnosis tools for the evaluation the T2DM patients with accompanying nephropathy. Extension of the lectin panel specific to O-glycans occurs useful for the further research using microarray formats, which are expected to accelerate “lectin-based glycan profiling” of glycoproteins.

Biochemical and clinical aspects of advanced oxidation protein products in kidney diseases and metabolic disturbances

Intensified oxidative modification of proteins and increased concentration of advanced oxidation protein products (AOPPs) are confirmed by many experimental investigations in different pathological states, especially these with well-known participation of oxidative stress (OS) in etiopathogenesis but also these with not well recognized its role. Presented data indicate that AOPPs play a significant role in many disorders with chronic background, because of they reflect both intensification of OS and the degree of pathological changes connected with OS in these diseases. This review sets out the clinical and diagnostic aspects of AOPPs in these diseases such as: renal diseases with different etiology, cardiovascular diseases, as well as connected with metabolic disturbances - e.g. diabetes, atherosclerosis or metabolic syndrome. Moreover results of investigation about utility of AOPPs measurement, mainly in plasma/serum, in these diseases are presented. The review and evaluation of application of AOPPs as useful marker in diagnosis, prognosis and monitoring the course of these diseases were performed. This paper also describes the suggested mechanisms of their action which contribute to biochemical and clinic changes undergoing in the condition of increased OS. Diagnostic or prognostic utility of AOPPs are especially indicated in the course of diabetes and its complications (diabetic nephropahy) and cardiovascular diseases.

Decreased melatonin levels and increased levels of advanced oxidation protein products in the seminal plasma are related to male infertility

Melatonin, an indolamine secreted by the pineal gland, is known as a powerful free-radical scavenger and wide-spectrum antioxidant. Therefore, the aim of this study was to correlate markers of oxidative protein damage (advanced oxidation protein products, AOPPs) and the total antioxidant capacity (TAC) with melatonin levels in the seminal plasma of men with azoospermia (n=37), theratozoospermia (n=29) and fertile controls (normozoospermia, n=37). Melatonin concentration was measured by radioimmunoassay. The levels of AOPP as well as TAC efficiency (determined by the ferric reducing antioxidant power, FRAP) were estimated by spectrophotometric methods. The concentration of melatonin and AOPP significantly differed in azoospermic (P<0.0001) and theratozoospermic (P<0.0001) patients versus fertile men, and correlated negatively (r=-0.33, P=0.0016). The TAC levels were significantly higher in azoospermia than in theratozoospermia (P=0.0022) and the control group (P=0.00016). In azoospermia, the AOPP concentration was also significantly higher than that observed in theratozoospermia (P=0.00029). Decreased levels of melatonin together with elevated AOPP altered the oxidative-antioxidative balance in the ejaculate, thereby reducing fertility. Therefore, melatonin and AOPP levels may serve as additional diagnostic markers of semen quality and male reproductive potential.

The advanced oxidation protein products as potential diagnostic and prognostic factor in diseases of the indicated participation of oxidative stress

The possibility of diagnostic and/or prognostic use of measuring the concentration of advanced oxidation protein products (AOPPs) in chronic diseases with well-documented involvement of oxidative stress (OS) in their pathogenesis were the subject of numerous studies. In the present study discussed the pathological conditions and disorders, in which the role of OS and oxidative damage of proteins is also indicated as one of the factors in their etiopathogenesis. The presented data concerned clinical and diagnostic aspects of AOPPs as well as biochemical mechanisms of disturbances in the infection and autoimmune diseases, cancers, genetic and neurological diseases. Participation of AOPPs in disturbances connected with fertility, pregnancy delivery and prematurity are also shown. Moreover the single literature data concerning other pathological states, in which AOPPs are also becoming the object of intensive investigations are presented. The review and application possibilities of AOPPs measurement as useful marker for diagnosis, prognosis and monitoring the course of these diseases were performed. Diagnostic or prognostic utility of AOPPs are especially indicated in the course of rheumatoid arthritis, development of pregnancy complication both in mother and child, and dementia. However, AOPPs measurement seems to be most promising in plasma or urine in course of cancer diseases.