Modification Of Plasma Proteins Research Articles

Modification of plasma protein for bioprinting via photopolymerization

Bioprinting is emerging as an advanced tool in tissue engineering. However, there is still a lack of bioinks able to form hydrogels with desirable bioactivities that support positive cell behaviors. In this study, modified plasma proteins capable of forming hydrogels with multiple biological functions are developed as bioinks for digital light processing (DLP) printing. The Plasma-MA (BM) was synthesized via a one-pot method through the reaction between the fresh frozen plasma and methacrylic anhydride. The methacrylated levels were observed to influence the physical properties of BM hydrogels including mechanical properties, swelling, and degradation. The photo-crosslinked BM hydrogels can sustainedly release vascular endothelial growth factor (VEGF) and exhibit positive biological effects on cell adhesion and proliferation, and cell functionality such as tube formation of human umbilical vein endothelial cells (HUVECs), and neurite elongation of rat pheochromocytoma cells (PC12). Meanwhile, BM hydrogels can also induce cell infiltration, modulate immune response, and promote angiogenesis in vivo. Moreover, the plasma bioinks can be used to fabricate customized scaffolds with complex structures through a DLP printing process. These findings implicate that the modified plasma with growth factor release is a promising candidate for bioprinting in autologous and personalized tissue engineering.

Increased Oxidative Stress in Acute Myeloid Leukemia Patients after Red Blood Cell Transfusion, but Not Platelet Transfusion, Results Mainly from the Oxidative/Nitrative Protein Damage: An Exploratory Study.

Chronic oxidative stress (OS) can be an important factor of acute myeloid leukemia (AML) progression; however, there are no data on the extent/consequence of OS after transfusion of packed red blood cells (pRBCs) and platelet concentrates (PCs), which are commonly used in the treatment of leukemia-associated anemia and thrombocytopenia. We aimed to investigate the effects of pRBC/PC transfusion on the OS markers, i.e., thiol and carbonyl (CO) groups, 3-nitrotyrosine (3-NT), thiobarbituric acid reactive substances (TBARS), advanced glycation end products (AGE), total antioxidant capacity (TAC), SOD, GST, and LDH, in the blood plasma of AML patients, before and 24 h post-transfusion. In this exploratory study, 52 patients were examined, of which 27 were transfused with pRBCs and 25 with PCs. Age-matched healthy subjects were also enrolled as controls. Our results showed the oxidation of thiols, increased 3-NT, AGE levels, and decreased TAC in AML groups versus controls. After pRBC transfusion, CO groups, AGE, and 3-NT significantly increased (by approximately 30, 23, and 35%; p < 0.05, p < 0.05, and p < 0.01, respectively) while thiols reduced (by 18%; p < 0.05). The PC transfusion resulted in the raise of TBARS and AGE (by 45%; p < 0.01 and 31%; p < 0.001), respectively). Other variables showed no significant post-transfusion changes. In conclusion, transfusion of both pRBCs and PCs was associated with an increased OS; however, transfusing the former may have more severe consequences, since it is associated with the irreversible oxidative/nitrative modifications of plasma proteins.

Роль анионного компонента в проявлении эффектов органических солей лития на окислительную модификацию белков и липидов крови больных депрессивными расстройствами

Введение. Литиевые соли широко используются в психиатрии. Изучение новых свойств солей лития с различными анионными компонентами является важной задачей. Цель исследования - изучение in vitro эффектов солей лития, содержащих разные органические анионные компоненты, на модификацию белков и липидов плазмы крови пациентов с депрессивными расстройствами (ДР). Методика. Инкубацию крови пациентов ДР с солями лития (аскорбат лития, сукцинат лития и пируват лития) проводили в течение 1 ч при 37 °С. В качестве окислительного агента использовали 0,5% этанол. Конечная концентрация в пробах ионов лития составляла 1,2 мМ. В плазме крови определяли количество окисленных белков по уровню карбонилированных белков (КБ) с использованием 2,4-динитрофенилгидразина, продукты перекисного окисления липидов - по содержанию продуктов, взаимодействующих с тиобарбитуровой кислотой (ТБК-реактивных продуктов, ТБК-РП). Результаты. У пациентов с ДР уровень КБ повышался по сравнению с контролем (здоровые лица), а концентрация ТБК-РП не отличалась от нормы. Инкубация крови здоровых лиц с 0,5%-ным этанолом приводила к увеличению содержания КБ и ТБК-РП плазмы, на уровень окисленных белков и липидов плазмы крови пациентов ДР в тех же условиях этанол влияния не оказывал. Аскорбат лития и пируват лития в присутствии этанола увеличивал уровень КБ в плазме крови пациентов ДР, сукцинат лития в этих условиях на КБ значимого эффекта не оказывал. На уровень ТБК-РП плазмы крови пациентов ДР все исследуемые соединения влияния не оказывали. В крови здоровых доноров соли лития проявляли антиоксидантный эффект, повышая устойчивость макромолекул плазмы к токсическому (окислительному) действию этанола. Заключение. Исследуемые соли лития в условиях эксперимента с применением в качестве окислительного агента этанола оказывали антиоксидантное действие на белки и липиды плазмы крови здоровых лиц. Соли лития, имеющие в своем составе анионы аскорбата или пирувата, проявляли прооксидантный эффект в образцах крови пациентов с депрессивными расстройствами, усиливая окислительное действие этанола на белки, но не на липиды плазмы. Таким образом, соли лития оказывают различное действие на окислительную модификацию белков и липидов крови здоровых лиц и пациентов депрессивными расстройствами in vitro, при этом анионный компонент соли играет важную роль в проявлении эффектов соединений. Introduction. Lithium salts are widely used in psychiatry. Studying new properties of lithium salts with various anionic components is important. The aim of this study was to compare in vitro effects of lithium salts containing different organic anionic components on oxidative modification of plasma proteins and lipids in patients with depressive disorders (DD). Methods. Blood of DD patients was incubated with lithium salts (lithium ascorbate, lithium succinate, and lithium pyruvate) at 37 °C for 1 hour. Ethanol was used as an oxidizing agent. Final concentrations of lithium ions and ethanol in a sample were 1.2 mM and 0.5%, respectively. Plasma content of oxidized proteins was determined by the content of carbonylated proteins (CP) using 2,4-dinitrophenylhydrazine. Lipid peroxidation products were determined by the content of thiobarbituric acid-reactive products (TBA-RP). Results. In DD patients, concentration of CP was increased compared to the control (healthy subjects) whereas concentration of TBA-RP did not differ from the control. Incubation of blood from healthy individuals with 0.5% ethanol resulted in increases in both the CP and TBA-RP whereas ethanol did not exert any effect on concentrations of oxidized proteins and TBA-RP in DD patients in the same conditions. Lithium ascorbate and lithium pyruvate in the presence of ethanol increased the CP concentration in blood from DD patients; lithium succinate left unchanged the CP concentration in these conditions. None of the studied compounds had any effect on TBA-RP in plasma of DD patients. In blood of healthy donors, lithium salts exerted an antioxidant effect increasing the resistance of plasma macromolecules to the toxic (oxidative) action of ethanol. Conclusion. The studied lithium salts produced an antioxidant effect in vitro on ethanol-induced oxidative modification of proteins and lipids in blood from healthy individuals. In blood samples from DD patients, lithium salts containing ascorbate or pyruvate anions showed pro-oxidant properties by potentiating the oxidative effect of ethanol on plasma proteins but not lipids. Therefore, lithium salts differently influence in vitro oxidative modification of proteins and lipids in blood of healthy people and DD patients with the anionic component of lithium salt playing an important role in manifestation of effects of these compounds.

Adrenergic alpha-2 receptor antagonists cease augmented oxidation of plasma proteins and anxiety of rats caused by chronic noise exposure.

Background:Noise is one of the environmental factors, which is considered as a powerful stressor for the organism. Generally, the acoustic stress affects the behavior and physiological state of humans and animals.Aims:The goal of this study is to investigate the relationship between chronic noise exposure and the effects of adrenergic alpha-2 receptor antagonists, beditin and mesedin, on the anxiety and oxidation of plasma proteins and fibrinogen in rats.Methods:The experiments were carried out on non-linear albino male rats, divided into four groups (six animals in each): 1. Healthy controls 2. Exposed to noise of a level 91 dB(A), eight hours daily, during 7, 30 and 60 days; 3. Injected with 2 mg/kg of beditin (2-(2-amino-4-thiazolyl)-1,4-benzodioxane hydrochloride)); 4. Injected with 10 mg/kg mesedin (2-(2-methyl-amino-thiozolyl)-1,4-benzodioxane hydrochloride). For evaluating the cognitive impairment, the Any-maze test was applied. The level of carbonylation of proteins was assessed by reaction with 2,4-dinitrophenylhydrazine, spectrophotometrically.Results:Chronic noise decreased locomotor activity and increased anxiety and oxidation of plasma protein and fibrinogen. Intensity of these changes were dependent on the duration of noise exposure.Conclusion:The Alpha 2 adrenoblockers alleviate oxidative modification of plasma proteins and reduce the cognitive impairment caused by chronic exposure to noise.

Oxidative Stress and Hemostatic Parameters in Patients With Nephrolithiasis Before and After Ureteroscopic Lithotripsy.

PurposeIn patients with nephrolithiasis, oxidative stress, especially lipid peroxidation is observed. Moreover, various invasive methods [including extracorporeal shock wave lithotripsy (ESWL)] for treatment of nephrolithiasis may induce not only the oxidative stress, but they may modulate hemostasis. The study was aimed to evaluate the oxidative damages of lipids and proteins in patients with nephrolithiasis (before and after ureteroscopic lithotripsy – URSL). The aim of the present study was also determine selected parameters of hemostasis in these patients.Methods56 patients with nephrolithiasis and 49 healthy participants were included: 30 men and 26 women (for patient group); 27 men and 22 women (for healthy group). We measured the level of selected typical two biomarkers of oxidative modification of lipids [such as the production of thiobarbituric acid reactive substances (TBARS) and isoprostane concentration (8-isoPGF2α)] and two biomarkers of oxidative damages of proteins (carbonylation and the level of thiol groups) in patients with nephrolithiasis (before and after URSL). The following parameters of hemostasis were measured: blood platelet count, the level of fibrinogen and D-dimer, and coagulation times (the activated partial thromboplastin time (APTT), prothrombin time (PT), and thrombin time (TT) of plasma).ResultsDifferent levels of plasma lipid peroxidation were observed in patients with nephrolithiasis before URSL and after URSL. However, no such difference in the level of oxidative damage to plasma proteins was observed. In addition, the tested hemostasis parameters were not influenced by the presence of nephrolithiasis, nor by treatment with URSL.ConclusionWe suggest URSL does not induce the oxidative modifications of plasma proteins and does not change hemostatic parameters in patients with nephrolithiasis.

Free Radical Activity as Diagnostic and Prognostic Criteria in Solid Tumors and Their Therapy

Blood plasma of 39 cancer patients who had not previously undergone anti-tumor treatment, and 21 patients with recurrent epithelial tissues cancer before treatment and after the first course of chemotherapy were investigated. The treatment effectiveness of patients with relapse was evaluated throughout the year. The control group was the blood plasma of 14 healthy people. Free radical activity and oxidative modification of proteins were assessed in blood plasma. In malignant neoplasms of epithelial tissues, free radical activity and oxidative modification of plasma proteins are significantly higher. At the initial stages of carcinogenesis, the oxidative modification level of plasma proteins increases both due to aldehyde and ketone carbonyl derivatives. In the terminal stage of malignant tumors, an increase in the oxidative modification of proteins occurs due to aliphatic ketone dinitrophenyl hydrazones, which are the markers of protein aggregation characteristic of the late stages of oxidative stress. In case of an objective response to polychemotherapy, there is a significant decrease in free radical plasma activity after the first course of therapy and a significant increase in carbonyl derivatives recorded at a wavelength of 230 nm, which can serve as a marker of its effectiveness.

Application and interpretation of functional data analysis techniques to differential scanning calorimetry data from lupus patients.

BackgroundDSC is used to determine thermally-induced conformational changes of biomolecules within a blood plasma sample. Recent research has indicated that DSC curves (or thermograms) may have different characteristics based on disease status and, thus, may be useful as a monitoring and diagnostic tool for some diseases. Since thermograms are curves measured over a range of temperature values, they are considered functional data. In this paper we apply functional data analysis techniques to analyze differential scanning calorimetry (DSC) data from individuals from the Lupus Family Registry and Repository (LFRR). The aim was to assess the effect of lupus disease status as well as additional covariates on the thermogram profiles, and use FD analysis methods to create models for classifying lupus vs. control patients on the basis of the thermogram curves.MethodsThermograms were collected for 300 lupus patients and 300 controls without lupus who were matched with diseased individuals based on sex, race, and age. First, functional regression with a functional response (DSC) and categorical predictor (disease status) was used to determine how thermogram curve structure varied according to disease status and other covariates including sex, race, and year of birth. Next, functional logistic regression with disease status as the response and functional principal component analysis (FPCA) scores as the predictors was used to model the effect of thermogram structure on disease status prediction. The prediction accuracy for patients with Osteoarthritis and Rheumatoid Arthritis but without Lupus was also calculated to determine the ability of the classifier to differentiate between Lupus and other diseases. Data were divided 1000 times into separate 2/3 training and 1/3 test data for evaluation of predictions. Finally, derivatives of thermogram curves were included in the models to determine whether they aided in prediction of disease status.ResultsFunctional regression with thermogram as a functional response and disease status as predictor showed a clear separation in thermogram curve structure between cases and controls. The logistic regression model with FPCA scores as the predictors gave the most accurate results with a mean 79.22% correct classification rate with a mean sensitivity = 79.70%, and specificity = 81.48%. The model correctly classified OA and RA patients without Lupus as controls at a rate of 75.92% on average with a mean sensitivity = 79.70% and specificity = 77.6%. Regression models including FPCA scores for derivative curves did not perform as well, nor did regression models including covariates.ConclusionChanges in thermograms observed in the disease state likely reflect covalent modifications of plasma proteins or changes in large protein-protein interacting networks resulting in the stabilization of plasma proteins towards thermal denaturation. By relating functional principal components from thermograms to disease status, our Functional Principal Component Analysis model provides results that are more easily interpretable compared to prior studies. Further, the model could also potentially be coupled with other biomarkers to improve diagnostic classification for lupus.

Increased serotransferrin and ceruloplasmin turnover in diet-controlled patients with type 2 diabetes

Type 2 diabetes mellitus (T2DM) is associated with oxidative stress and perturbed iron metabolism. Serotransferrin (Trf) and ceruloplasmin (Cp) are two key proteins involved in iron metabolism and anti-oxidant defense. Non-enzymatic glycation and oxidative modification of plasma proteins are known to occur under hyperglycemia and oxidative stress. In this study, shotgun proteomics and 2H2O-based metabolic labeling were used to characterize post-translational modifications and assess the kinetics of Trf and Cp in T2DM patients and matched controls in vivo. Six early lysine (Amadori) and one advanced arginine glycation were detected in Trf. No glycation, but five asparagine deamidations, were found in Cp. T2DM patients had increased fractional catabolic rates of both Trf and Cp that correlated with HbA1c (p < 0.05). The glycated Trf population was subject to an even faster degradation compared to the total Trf pool, suggesting that hyperglycemia contributed to an increased Trf degradation in T2DM patients. Enhanced production of Trf and Cp kept their levels stable. The changes in Trf and Cp turnover were associated with increased systemic oxidative stress without any alteration in iron status in T2DM. These findings can help better understand the potential role of altered Trf and Cp metabolism in the pathogenesis of T2DM and other diseases.

Assessment of oxidative/nitrative modifications of plasma proteins, selected ROTEM parameters and kinetics of fibrinogen polymerization in patients with multiple myeloma at diagnosis.

Patients with multiple myeloma (MM) are at increased risk of thrombosis. Growing evidence indicates that oxidative and nitrative modifications of proteins, including fibrinogen, may lead to changes in hemostasis. The study compares samples from patients with MM at diagnosis and healthy volunteers with regard to the oxidative/nitrative modifications of proteins, ROTEM and thrombin-catalyzed fibrin polymerization. The content of carbonyl groups in plasma proteins of patients with MM was significantly higher than in controls (2.981 vs. 1.807nmol/mg of protein, p=0.005), while no differences were seen in the concentrations of nitrated proteins. Maximum clot firmness readings were significantly higher in the samples of patients than in controls according to FIBTEM test (23.5 vs. 15mm, p=0.006). The lag time of the fibrin polymerization process and the velocity of clot lysis (V Lys) were found to be significantly higher in the group of MM patients than controls. In contrast, no marked differences were identified between studied groups in reference to maximal velocity of fibrin polymerization process (V max), maximal absorbance (A max) and plasmin amidolytic activity values. In conclusion, our study demonstrates that at the time of diagnosis, patients with MM demonstrated greater oxidative stress than healthy volunteers, which is reflected in a higher amount of carbonylated proteins. Some prothrombotic features found in ROTEM tests in MM patients were not confirmed by turbidimetry.

Expression and oxidative modifications of plasma proteins in autism spectrum disorders: Interplay between inflammatory response and lipid peroxidation.

A role for inflammation and oxidative stress is reported in autism spectrum disorders (ASDs). Here, we tested possible changes in expression and/or oxidative status for plasma proteins in subjects with ASDs. To evaluate protein expression and protein adducts of lipid peroxidation-derived aldehyde, analysis of plasma proteins was performed in 30 subjects with ASDs and compared with 30 healthy controls with typical development, using a proteomic approach. Significant changes were evidenced for a total of 12 proteins. Of these, ten were identified as proteins involved in the acute inflammatory response including alpha-2-macroglobulin, alpha-1-antitrypsin, haptoglobin, fibrinogen, serum transferrin, prealbumin, apolipoprotein A-I apolipoprotein A-IV, apolipoprotein J, and serum albumin. In addition, significant changes occurred for two immunoglobulins alpha and gamma chains. Our present data indicate that an inflammatory response, coupled with increased lipid peroxidation, is present in subjects with ASDs. This information can provide new insight into the identification of potential plasma protein biomarkers in autism.

Effect of a calorically restricted dietary regime on oxidative post-translational modifications of plasma proteins in mice and rats

Effect of a calorically restricted dietary regime on oxidative post-translational modifications of plasma proteins in mice and rats

Investigation of the antioxidant activity and cardioprotective effect of reamberin and cytoflavin in newborn rats exposed to chronic hemic hypoxia

The authors analyzed the antioxidant activity of reamberin and cytoflavin and evaluated their cardioprotective effect, by investigating lipid peroxidation and oxidative modification of plasma proteins, as well as the ultrastructure of newborn rat cardiomyocytes under chronic hemic hypoxia induced by sodium nitrite. Reamberin and cytoflavin can reduce the manifestations of mitochondrial dysfunction and the degree of cardiomyocyte damage in the neonatal rats due to the antioxidant and membrane-protective properties of the drugs. Succinic acid in combination with the metabolic components of the drugs significantly inhibits lipid peroxidation, by improving the structure of membranes and the mitochondrial function of cardiomyocytes.

Consumption of Purple Sweet Potato Affects Post-Translational Modification of Plasma Proteins in Hamsters

A high level of intake of vegetables is strongly associated with the prevention of chronic diseases. Because post-translational modifications (PTMs) have been shown to be the important biomarkers of the change in physiological functions, this study aimed to explore the changes in PTMs of plasma proteins when purple sweet potato (PSP), a root vegetable, was incorporated into the daily diet. Male Syrian hamsters were maintained on a rice diet (50% rice) or PSP diet (25% rice and 25% PSP) for 12 weeks. Plasma proteins were fractionated by electrophoresis, digested by trypsin, and then separated by nano-liquid chromatography and tandem mass spectrometry. The TurboSequest algorithm was used to identify peptide sequence against the hamster database in Universal Proteins Resource Knowledgebase, and in-house PTM finder programs were used for identification and quantification of PTMs. The results indicated that 95 plasma proteins were identified and 28 PTM sites on 26 of these 95 proteins were affected by consumption of PSP (p < 0.05). Methylation accounted for the largest percentage of affected modifications (35.71%). This study also showed that incorporation of purple sweet potato into the diet significantly lowered blood and liver lipids (p < 0.05). The results of this study provide a basis for prospective studies evaluating the effects of dietary intervention on modifications of proteins.

Neutrophils Turn Plasma Proteins into Weapons against HIV-1

As a consequence of innate immune activation granulocytes and macrophages produce hypochlorite/hypochlorous acid (HOCl) via secretion of myeloperoxidase (MPO) to the outside of the cells, where HOCl immediately reacts with proteins. Most proteins that become altered by this system do not belong to the invading microorganism but to the host. While there is no doubt that the myeloperoxidase system is capable of directly inactivating HIV-1, we hypothesized that it may have an additional indirect mode of action. We show in this article that HOCl is able to chemically alter proteins and thus turn them into Idea-Ps (Idea-P = immune defence-altered protein), potent amyloid-like and SH-groups capturing antiviral weapons against HIV-1. HOCl-altered plasma proteins (Idea-PP) have the capacity to bind efficiently and with high affinity to the HIV-1 envelope protein gp120, and to its receptor CD4 as well as to the protein disulfide isomerase (PDI). Idea-PP was able to inhibit viral infection and replication in a cell culture system as shown by reduced number of infected cells and of syncytia, resulting in reduction of viral capsid protein p24 in the culture supernatant. The unmodified plasma protein fraction had no effect. HOCl-altered isolated proteins antithrombin III and human serum albumin, taken as representative examples of the whole pool of plasma proteins, were both able to exert the same activity of binding to gp120 and inhibition of viral proliferation. These data offer an opportunity to improve the understanding of the intricacies of host-pathogen interactions and allow the generation of the following hypothetical scheme: natural immune defense mechanisms generate by posttranslational modification of plasma proteins a potent virucidal weapon that immobilizes the virus as well as inhibits viral fusion and thus entry into the host cells. Furthermore simulation of this mechanism in vitro might provide an interesting new therapeutic approach against microorganisms.

Oxidative modification of patient's plasma proteins and its role in pathogenesis of multiple sclerosis

BackgroundOxidative stress plays an important role in multiple sclerosis (MS). Objective and methodsThe present study was designed to evaluate the modifications of plasma proteins by estimation markers of oxidative/nitrosative stress: carbonyl groups and 3-nitrotyrosines (3-NT) levels in relapsing-remitting (RR) (n=10) and secondary progressive (SP) (n=10) clinical course of multiple sclerosis. Moreover, we estimated the level of uric acid (UA) in plasma of MS patients. ResultsCompared to controls (n=10), the levels of carbonyl groups in plasma proteins were elevated (P<0.0001) as well in RRMS as in SPMS. The highest concentration of 3-NT was observed in plasma proteins obtained from SPMS patients (P<0.0005). The level of uric acid in plasma was significantly lower in RRMS (P<0.0001) than SPMS. ConclusionThis is the first report which presented differences between SPMS and RRMS patients in 3-NT and protein carbonyl groups in plasma proteins.

Plasma nitroproteome of kidney disease patients

3'-Nitrotyrosine (3NT) is a post-translational modification (PTM) of body fluids and tissues that is sustained by chronic inflammation and oxidative stress, two main clinical traits of chronic kidney disease (CKD). Despite this background, protein targets and their differential susceptibility to in vivo nitration remain almost completely unexplored in CKD. This study reports a first investigation of plasma nitroproteome in these patients, carried out by both immunorecognition and LC-MS/MS techniques. Plasma proteins of chronic and end-stage KD patients showed a higher burden of nitration than in healthy controls, but main nitration targets appeared to be the same in these populations. Immunoblotting data showed that uremic albumin is largely represented in the uremic nitroproteome together with fibrinogen chains (A, B and C), transferrin, α1-antitrypsin, complement factor D, haptoglobin, and IgG light and heavy chains. However, immunopurification and affinity chromatography experiments demonstrated that the relative content of 3NT on the albumin molecule was very low when compared with that of the remaining plasma proteins. The uremic nitroproteome was investigated using also plasma proteins obtained by in vivo ultrafiltration from patients treated with protein leaking or standard high-flux hemodialyzers. The study of these samples revealed the possibility to selectively remove protein nitration products during hemodialysis. Identification of intramolecular sites of nitration was preliminarily obtained in IgG chains isolated by 2D PAGE and assessed by bidimensional tandem mass spectrometry after chemoselective tagging. Further studies are needed to confirm at the molecular level the presence of nitrated Tyr residues in other proteins tentatively identified as nitration targets in this study and to explore the biological meaning of such a selective modification of plasma proteins by reactive nitrogen species in uremia and dialysis patients.

Apolipoprotein, C-Reactive Protein and Oxidative Stress Parameters in Dyslipidemic Type 2 Diabetic Patients Treated or Not with Simvastatin

Oxidative stress is considered an important factor in the development of diabetic complications that causes a variety of changes such as oxidative modification of membrane lipids, nucleic acids and cellular proteins. Dyslipidemia is frequently associated with diabetes and cardiovascular disease. In this context, the objective of this study was to evaluate oxidative modifications of plasma proteins and lipids in non dyslipidemic type 2 diabetic (T2D) patients, in dyslipidemic T2D patients treated or not with simvastatin and in healthy subjects to investigate whether treatment with low doses of simvastatin plays a protective role on the lipid and protein oxidative damage in these patients. We determined oxidative damage of plasma proteins by carbonyl assay and total thiol group determination. We also characterized the membrane damage in terms of lipid peroxidation by measuring malonaldehyde (MDA) in nondyslipidemic T2D patients, dyslipidemic T2D patients treated with simvastatin (20 mg/day), dyslipidemic T2D patients not treated with simvastatin and in healthy age-matched control subjects. Our results showed that dyslipidemic T2D patients not treated with simvastatin had significantly higher plasma protein carbonyl groups and MDA when compared to dyslipidemic T2D patients treated with simvastatin and control group. Thiol concentrations from dyslipidemic T2D patients not treated with simvastatin were significantly lower than treated patients and controls. It was verified that the thiols groups were inversely correlated with apolipoprotein B and positively correlated with apolipoprotein A-I. These results demonstrated that treatment with low doses of simvastatin can minimize the protein and lipid oxidative damage in dyslipidemic T2D patients.

Chapter 11 - Redox State of Human Serum Albumin in Terms of Cysteine-34 in Health and Disease

Albumin, the main protein in plasma, is prone to different mechanisms of oxidative modification since extracellular fluids contain only small amounts of antioxidant enzymes. The redox state of cysteine-34 of human albumin defines three fractions which allow to monitor albumin oxidation: mercaptalbumin with a free thiol group, nonmercaptalbumin1 containing a disulfide, and nonmercaptalbumin2 with a sulfinic or sulfonic acid group. These fractions can be separated by HPLC and detected with UV or fluorescence detection. The method is very rugged and only simple sample preparation is needed. It has been used to demonstrate albumin oxidation during exercise, aging, and pathologies like diabetes, liver disease, or renal disease. Problems may arise when high endogenous concentrations of bilirubin or certain drugs are present. The redox state of albumin shows high variability and is hence a valuable tool for the investigation of reversible and irreversible modification of plasma protein.

Oxidative modification of proteins and blood antioxidant activity of ground squirrels during induced awakening from hibernation

The intensity of oxidative modification of plasma proteins and activity of the antioxidative system of the blood of the ground squirrels during awakening from hibernation is studied. During waking of animals, processes of oxidative modification of proteins in the blood plasma intensify. While the body temperature rises, the antioxidative activity of hydrophylic components of the blood plasma grows essentially, and erythrocyte superoxide dismutase too. Activity of erythrocyte catalase at all stages of waking is definitely higher than in the control. The received results evidence that the high activity of various links of antioxidative blood protection provides stability to oxidative stress during waking of animals from deep sleep.

Oxidative/Nitrative Modifications of Plasma Proteins and Thiols from Patients with Schizophrenia

Objective: The level of various specific biomarkers of oxidative stress in plasma from schizophrenic patients, as well as biomarkers (the level of isoprostanes) in urine in schizophrenic patients was described. The aim of our present study was to evaluate biomarkers of oxidative stress by oxidative/nitrative modifications of plasma proteins (by measuring the level of carbonyl groups and 3-nitrotyrosine in proteins) from patients with schizophrenic disorders and from control group. We also investigated the level of low-molecular-weight thiols [glutathione (GSH), cysteine (CSH), cysteinylglycine (CGSH) and homocysteine] in plasma obtained from schizophrenic patients and from healthy volunteers. Patients hospitalized in the 1st and 2nd Psychiatric Department of the Medical University in Lodz, Poland were interviewed with a special questionnaire (treatment, course of diseases, dyskinesis and other extrapyramidal syndromes). According to DSM-IV criteria, all patients had a diagnosis of paranoid type. They were treated with antipsychotic drugs (clozapine, risperidone, olanzapine). The mean duration of schizophrenia was about 5 years. Methods: Levels of carbonyl groups and 3-nitrotyrosine residues in plasma proteins were measured by ELISA and a competition ELISA, respectively. High-performance liquid chromatography was used to analyze free thiols in plasma. Results: We observed a statistically increased level of biomarkers of oxidative/nitrative stress such as carbonyl groups or 3-nitrotyrosine in plasma proteins from schizophrenic patients. In schizophrenic patients the amount of homocysteine in plasma was higher compared with the control group; the level of GSH, CSH and CGSH was decreased. This indicates that reactive oxygen species and reactive nitrogen species may stimulate oxidative/nitrative modifications of plasma proteins in schizophrenic patients. Conclusion: Considering the data presented in this study, we suggest that the amount of carbonyl groups and 3-nitrotyrosine in plasma proteins may be important indicators of protein damage in vivo in schizophrenia.