Publications by authors named "Marcin Talar"

19 Publications

  • Page 1 of 1

Expression of FFAR3 and FFAR4 Is Increased in Gastroesophageal Reflux Disease.

J Clin Med 2020 Dec 20;9(12). Epub 2020 Dec 20.

Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, 92-215 Lodz, Poland.

Background: The negative impact of a high-fat diet on the course of gastroesophageal reflux disease (GERD) has been previously reported. Free fatty acid receptors (FFARs) may be mediators of this phenomenon. The aim of this study was to characterize the role of FFARs in the course of nonerosive (NERD) and erosive (ERD) reflux disease.

Methods: Collectively, 73 patients (62 with GERD and 11 healthy controls (HCs)) were recruited to the study. Esophageal biopsies were drawn from the lower third of the esophagus and kept for further experiments. Quantitative, real-time polymerase chain reaction was used to assess the expression of FFAR1, FFAR2, FFAR3, and FFAR4 in biopsies. Histological evaluation of dilated intracellular spaces (DISs) was also performed.

Results: FFAR3 exhibited the highest expression, and FFAR4 exhibited the lowest expression in all esophageal samples. Higher relative expression of FFAR1 and FFAR2 and significantly higher expression of FFAR3 ( = 0.04) was noted in patients with GERD compared to respective HCs. Patients with nonerosive GERD (NERD) presented higher expression of all FFARs compared to patients with erosive GERD (ERD) and respective HCs. Interestingly, in patients with ERD, the expression of FFAR3 was lower than in HCs. Significant, weak, positive correlation was found for FFAR3 and FFAR4 expression and DIS scores (r = 0.36, < 0.05 for FFAR 3, and r = 0.39, < 0.05 for FFAR4).

Conclusions: In this study, we show that FFARs may play a role in GERD pathogenesis, particularly in the NERD type. It may be assumed that FFARs, in particular FFAR3 and FFAR4, may have diagnostic and therapeutic potential in GERD.
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http://dx.doi.org/10.3390/jcm9124111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7766740PMC
December 2020

Intravital Assessment of Blood Platelet Function. A Review of the Methodological Approaches with Examples of Studies of Selected Aspects of Blood Platelet Function.

Int J Mol Sci 2020 Nov 6;21(21). Epub 2020 Nov 6.

Department of Haemostasis and Haemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, 92-215 Lodz, Poland.

Platelet biology owes to intravital studies not only a better understanding of platelets' role in primary hemostasis but also findings that platelets are important factors in inflammation and atherosclerosis. Researchers who enter the field of intravital platelet studies may be confused by the heterogeneity of experimental protocols utilized. On the one hand, there are a variety of stimuli used to activate platelet response, and on the other hand there are several approaches to measure the outcome of the activation. A number of possible combinations of activation factors with measurement approaches result in the aforementioned heterogeneity. The aim of this review is to present the most often used protocols in a systematic way depending on the stimulus used to activate platelets. By providing examples of studies performed with each of the protocols, we attempt to explain why a particular combination of stimuli and measurement method was applied to study a given aspect of platelet biology.
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http://dx.doi.org/10.3390/ijms21218334DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7664321PMC
November 2020

The Impact of Virtual Reality Training on the Quality of Real Antromastoidectomy Performance.

J Clin Med 2020 Oct 2;9(10). Epub 2020 Oct 2.

Department of Otolaryngology and Laryngological Oncology, Poznań University of Medical Sciences, 60-355 Poznań, Poland.

Background: The aim of this paper is to analyze the results of virtual reality (VR) antromastoidectomy simulation training and the transferability of the obtained skills to real temporal bone surgery.

Methods: The study was conducted prospectively on a group of 10 physicians, and was composed of five VR simulation training sessions followed by live temporal bone surgery. The quality of performance was evaluated with a Task-Based Checklist (TBC) prepared by John Hopkins Hospital. Additionally, during every VR session, the number and type of mistakes (complications) were noted.

Results: The quality of performance measured by the TBC increased significantly during consecutive VR sessions. The mean scores for the first and fifth sessions were 1.84 and 4.27, respectively ( 0.001). Furthermore, the number of mistakes in consecutive VR sessions was gradually reduced from 11 to 0. During supervised surgery, all the participants were able to perform at least part of an antromastoidectomy, and the mean TBC score was 3.57. There was a significant strong positive correlation between the individual results of the fifth VR session and the individual results of supervised surgery in the operating room (r = 0.89, 0.001).

Conclusions: Virtual reality for temporal bone training makes it possible to acquire surgical skills in a safe environment before performing supervised surgery. Furthermore, the individual final score of virtual antromastoidectomy training allows a prediction of the quality of performance in real surgery.
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http://dx.doi.org/10.3390/jcm9103197DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7600885PMC
October 2020

data: treatment with the F11R/JAM-A peptide 4D decreases mortality and reduces the generation of atherosclerotic plaques in ApoE-deficient mice.

Data Brief 2020 Jun 23;30:105516. Epub 2020 Apr 23.

Department of Medicine, State University of New York, Downstate Medical Center, Brooklyn, New York 11203, USA.

The data in this article focus on the F11 Receptor (F11R/JAM-A; Junctional Adhesion Molecule-A; JAM-A, F11R), a cell adhesion protein constitutively expressed on the membrane surface of circulating platelets and localized within the tight junctions of healthy endothelial cells (ECs). Previous reports have shown that F11R/JAM-A plays a critical role in the adhesion of platelets to an inflamed endothelium due to its' pathological expression on the luminal surface of the cytokine-inflamed endothelium. Since platelet adhesion to an inflamed endothelium is an early step in the development of atherosclerotic plaque formation, and with time, resulting in heart attacks and stroke, we conducted a long-term, study utilizing the atherosclerosis-prone ApoE mice to attempt a blockade of the formation of atherosclerotic plaques by preventing the adhesion of platelets to the inflamed vasculature . Utilizing a nonhydrolyzable peptide derived from an amino acid sequence of F11R/JAM-A, peptide 4D, we have shown that the adhesion of platelets to the inflamed endothelial cells could be blocked by peptide 4D. The present data demonstrate the positive health benefits of chronic peptide 4D administration to the atherosclerosis-prone ApoE mice, and provides new information for potential use of this F11R derived peptide in the prevention of atherosclerosis. The data presented in this article provide further experimental support for the study presented in Babinska et al., Atherosclerosis 284 (2019) 92-101.
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http://dx.doi.org/10.1016/j.dib.2020.105516DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7206208PMC
June 2020

A peptide antagonist of F11R/JAM-A reduces plaque formation and prolongs survival in an animal model of atherosclerosis.

Atherosclerosis 2019 05 22;284:92-101. Epub 2019 Feb 22.

Department of Medicine, State University of New York, Downstate Medical Center, Brooklyn, NY, 11203, USA.

Background And Aims: The F11 Receptor (F11R), AKA Junctional Adhesion Molecule-A (JAM-A) (F11R/JAM-A), is an adhesion protein constitutively expressed on the membrane surface of circulating platelets and the luminal surface of inflamed endothelial cells (EC). Platelet adhesion to an inflamed endothelium is one of the early steps of atherosclerotic plaque formation. Our previous studies, conducted with cultured EC in vitro, have demonstrated the expression of F11R/JAM-A on the luminal surface of inflamed EC, platelet adhesion to inflamed EC through F11R/JAM-A interactions, and inhibition of this interaction by the presence of F11R/JAM-A antagonistic peptide (F11Rpeptide 4D). In the present study, we examined in vivo the overall health-benefits and cardiovascular effects of long-term treatment of animals prone to atherosclerosis, ApoE mice, with F11R-peptide 4D.

Methods: Twenty ApoE mice were assigned to daily treatment with peptide 4D and compared to their counterparts control untreated mice. Mice were observed for wellness and survival. Plaque size in the aorta and heart was measured using histological analysis. Effects of peptide 4D (or scramble control) on platelet adhesion to inflamed endothelium were measured using intravital microscopy.

Results: Significant reductions in atherosclerotic plaques number and size, an overall robust health with longer survival were found in the peptide 4D treated group of ApoE mice. Intravital microscopic studies conducted in exposed vessels of ApoE mice demonstrated significant inhibition by peptide 4D of platelet adhesion to the cytokine-inflamed endothelium.

Conclusions: Our results demonstrate that peptide 4D significantly reduces atherosclerotic plaque formation in ApoE mice and inhibits platelet adhesion to the inflamed arterial endothelium.
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http://dx.doi.org/10.1016/j.atherosclerosis.2019.02.014DOI Listing
May 2019

Effects of three-month streptozotocin-induced diabetes in mice on blood platelet reactivity, COX-1 expression and adhesion potential.

Int J Exp Pathol 2019 02 27;100(1):41-48. Epub 2019 Feb 27.

Department of Haemostatic Disorders, Chair of Biomedical Sciences, Faculty of Health Sciences, Medical University of Lodz, Lodz, Poland.

Diabetes is associated with an increased risk of cardiovascular disease. This is partially attributed to an altered activation status of blood platelets in this disease. Previously, alterations have been shown in COX-1 and protease activated receptor (PAR)-3 receptor expression in platelets in two animal models of diabetes, there have not been studies which address expression of these proteins in mice with long-term streptozotocin (STZ)-induced diabetes. We have also addressed the effect of diabetes on platelet adhesion under flow conditions. With the use of flow cytometry, we have shown that certain markers of platelet basal activation, such as active form of α β and of CD40L were increased in STZ-induced diabetic mice. Platelets from STZ-induced diabetic mice were also more reactive when stimulated with PAR-4 activating peptide as revealed by higher expression of active form of α β , membrane-bound on vWillebrand Factor and binding of exogenous fluorescein isothyanate-labelled fibrinogen. Expression of COX-1 and production of thromboxane A in platelets of STZ-induced diabetic mice were higher than in control animals. We observed no effect of diabetes on ability of platelets to form stable adhesions with fibrinogen in flow conditions. We conclude that although certain similarities exist between patterns of activation of platelets in animal models of diabetes, the differences should also be taken into account.
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http://dx.doi.org/10.1111/iep.12298DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6463392PMC
February 2019

Comparison of different microscopy approaches to quantification of inhibitory effect on thrombus formation under flow conditions by the example of adenosine receptor agonist HE-NECA.

J Pharmacol Toxicol Methods 2018 Nov - Dec;94(Pt 1):94-104. Epub 2018 Jul 19.

Department of Haemostatic Disorders, Chair of Biomedical Sciences, Faculty of Health Sciences, Medical University of Lodz, 6/8 Mazowiecka Street, 92-235 Lodz, Poland.

Introduction: Thrombus formation in vitro in flow conditions and its visualization and quantification with the use of microscopy are widely utilized to evaluate activity of compounds with a potential antithrombotic activity. Visualization and quantification of thrombi can be performed with the use of wide-field or confocal microscopy. Acquiring reliable numerical data from wide-field microscopy images of objects which have a complex three-dimensional structure is strongly influenced by the methods used for image analysis. This can be a possible source of inaccuracy in assessment of antithrombotic activity of a tested substance. We aimed to verify how different approaches to the quantification of wide-field images can affect the evaluation of an antiplatelet effect of a tested substance.

Methods: We compared three algorithms of image analysis to evaluate an effect of 2-hexynyl-5'-ethylcarboxamidoadenosine (HE-NECA), a compound of a moderate antiplatelet activity on thrombus formation, and of abciximab - a potent antiplatelet compound. Also, we studied how the results obtained in a wide-field imaging correspond to those obtained by means of confocal imaging.

Results: Three algorithms for analysis of wide-field images showed antiplatelet effect of HE-NECA or abciximab. Absolute values of thrombus area and outcomes of the evaluation of inhibition efficacy of HE-NECA were significantly different between the algorithms. Analysis of volumes and heights of thrombi obtained by confocal imaging confirmed inhibitory effect of HE-NECA, but the evaluated levels of inhibition were significantly different from that obtained by wide-field imaging.

Discussion: We conclude that wide-field imaging provides reliable qualitative data on an inhibitory effect on thrombus formation, despite differences which can emerge from various approaches to image analysis. However, quantitative evaluation and comparison of the efficacy of inhibitors on the basis of total area occupied by thrombi obtained by wide-field microscopy should be made with caution. To obtain a reliable quantitative assessment of the effect of a tested compound on thrombus structure the use of confocal microscopy is inevitable.
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http://dx.doi.org/10.1016/j.vascn.2018.07.003DOI Listing
December 2018

Enhanced adhesion of blood platelets to intact endothelium of mesenteric vascular bed in mice with streptozotocin-induced diabetes is mediated by an up-regulated endothelial surface deposition of VWF - In vivo study.

Platelets 2018 Jul 26;29(5):476-485. Epub 2017 Jul 26.

a Department of Haemostasis and Haemostatic Disorders , Medical University of Lodz , Lodz , Poland.

Numerous in vitro experiments have confirmed that a dysfunctional endothelium is characterized by, inter alia, a higher affinity for binding of platelets and leukocytes. However, there is still no direct evidence for greater interaction between platelets and intact endothelium in in vivo animal models of diabetes. Therefore, the present study examines the pro-adhesive properties of endothelium change in vivo as an effect of streptozotocin (STZ)-induced diabetes and the role of two key platelet receptors: GPIb-IX-V and GPIIb/IIIa. Mice of C57BL strain with streptozotocin-induced diabetes were used in the study. Flow cytometry was used to assess basal activation and reactivity of platelets. Adhesion of platelets to the vascular wall was visualized with the use of intravital microscopy in mesentery. The contribution of GPIIb/IIIa and GPIb-IX-V was evaluated by the injection of Fab fragments of respective antibodies. The integrity of the endothelium and vWf expression were evaluated histochemically. Basal activation and reactivity of platelets in streptozotocin-diabetic mice were elevated. Blood platelets adhered more often to the vascular wall of diabetic mice than nondiabetic animals: 11.9 (6.4; 32.8) plt/min/mm (median [IQR]) vs 2.7 (1.3; 6.4) plt/min/mm. The injection of anti-GPIbα antibodies decreased the number of adhering platelets from 89.5 (34.0; 113.1) plt/min/mm (median [IQR]) in mice treated with isotype antibodies to 3.1 (1.7; 5.6) plt/min/mm in mice treated with blocking antibodies. The effect of GPIIb/IIIa blockage was not significant. Immunohistochemistry revealed a higher expression of vWF in the endothelium of STZ mice, but no substantial changes in endothelial morphology were detected. To conclude, the study shows that the platelets interact more frequently with the mesenteric vascular bed in mice with 1-month STZ-induced diabetes than in healthy mice. These interactions are mediated via platelet GPIb-IX-V and are driven by increased expression of vWF in endothelial cells.
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http://dx.doi.org/10.1080/09537104.2017.1332365DOI Listing
July 2018

Flow cytometry analysis reveals different activation profiles of thrombin- or TRAP-stimulated platelets in db/db mice. The regulatory role of PAR-3.

Blood Cells Mol Dis 2017 06 22;65:16-22. Epub 2017 Mar 22.

Department of Haemostasis and Haemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, 6/8 Mazowiecka str., 92-215 Lodz, Poland.

Introduction: Recent studies have shown that it may be the concentration of thrombin, which is discriminative in determining of the mechanism of platelet activation via protease activated receptors (PARs). Whether the observed phenomenon of differentiated responses of mouse platelets to various thrombin concentrations in non-diabetic db/+ and diabetic db/db mice depends upon the concerted action of various PARs, remains to be established.

Results: We found elevated reactivity of platelets, as well as the enhanced PAR-3 expression in response to both the used concentrations of AYPGKF in db/db mice, as compared to db/+ heterozygotes. At low concentration of thrombin platelets from diabetic mice demonstrated hyperreactivity, reflected by higher expression of PAR-3. For higher thrombin concentration, blood platelets from db/db mice appeared hyporeactive, compared to db/+ animals, while no significant differences in PAR-3 expression were observed between diabetic and non-diabetic mice.

Conclusions: The novel and previously unreported finding resulting from our study is that the increased expression of PAR-3 in response to either TRAP for PAR-4 or low thrombin (when PAR-4 is not the efficient thrombin receptor) may be one of the key events contributing to higher reactivity of platelets in db/db mice.
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http://dx.doi.org/10.1016/j.bcmd.2017.03.011DOI Listing
June 2017

Pentoxifylline Inhibits WNT Signalling in β-Cateninhigh Patient-Derived Melanoma Cell Populations.

PLoS One 2016 28;11(6):e0158275. Epub 2016 Jun 28.

Department of Molecular Biology of Cancer, Medical University of Lodz, Lodz, Poland.

Background: The heterogeneity of melanoma needs to be addressed and combination therapies seem to be necessary to overcome intrinsic and acquired resistance to newly developed immunotherapies and targeted therapies. Although the role of WNT/β-catenin pathway in melanoma was early demonstrated, its contribution to the lack of the melanoma patient response to treatment was only recently recognized. Using patient-derived melanoma cell populations, we investigated the influence of pentoxifylline on melanoma cells with either high or low expression of β-catenin.

Findings: Our results indicate that pentoxifylline inhibits the activity of the canonical WNT pathway in melanoma cell populations with high basal activity of this signalling. This is supported by lowered overall activity of transcription factors TCF/LEF and reduced nuclear localisation of active β-catenin. Moreover, treatment of β-cateninhigh melanoma cell populations with pentoxifylline induces downregulation of genes that are targets of the WNT/β-catenin pathway including connective tissue growth factor (CTGF) and microphthalmia-associated transcription factor (MITF-M), a melanocyte- and melanoma cell-specific regulator.

Conclusions: These results suggest that pentoxifylline, a drug approved by the FDA in the treatment of peripheral arterial disease, might be tested in a subset of melanoma patients with elevated activity of β-catenin. This pharmaceutical might be tested as an adjuvant drug in combination therapies when the response to immunotherapy is prevented by high activity of the WNT/β-catenin pathway.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158275PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4924839PMC
July 2017

Non-enzymatic modifications of prostaglandin H synthase 1 affect bifunctional enzyme activity - Implications for the sensitivity of blood platelets to acetylsalicylic acid.

Chem Biol Interact 2016 Jun 12;253:78-92. Epub 2016 Apr 12.

Department of Haemostasis and Haemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, 6/8 Mazowiecka str., 92-215, Lodz, Poland. Electronic address:

Due to its ability to inhibit the blood platelet PGHS-1, acetylsalicylic acid (ASA, Aspirin(®)) is widely used as a preventive agent in atherothrombotic diseases. However, its beneficial effects seem to be lower in diabetic patients, suggesting that protein glycation may impair effective ASA-mediated acetylation process. On the other hand, it is proposed that ASA can prevent some of the late complications of diabetes by lowering the extent of glycation at protein free amino groups. The aim of this work was to evaluate the extents of non-enzymatic N-glycosylation (glycation) and acetylation of blood platelet PGHS-1 (COX-1) and the competition between glycation and acetylation was investigated in order to demonstrate how these two reactions may compete against platelet PGHS-1. When PGHS-1 was incubated with glycating/acetylating agents (glucose, Glu; 1,6-bisphosphofructose, 1,6-BPF; methylglyoxal, MGO, acetylsalicylic acid, ASA), the enzyme was modified in 13.4 ± 1.6, 5.3 ± 0.5, 10.7 ± 1.2 and 6.4 ± 1.1 mol/mol protein, respectively, and its activity was significantly reduced. The prior glycation/carbonylation of PGHS-1 with Glu, 1,6-BPF or MGO decreased the extent of acetylation from 6.4 ± 1.1 down to 2.5 ± 0.2, 3.6 ± 0.3 and 5.2 ± 0.2 mol/mol protein, respectively, but the enzyme still remained susceptible to the subsequent inhibition of its activity with ASA. When PGHS-1 was first acetylated with ASA and then incubated with glycating/carbonylating agents, we observed the following reductions in the enzyme modifications: from 13.4 ± 1.6 to 8.7 ± 0.6 mol/mol protein for Glu, from 5.3 ± 0.5 to 3.9 ± 0.3 mol/mol protein for 1,6-BPF and from 10.7 ± 1.2 to 7.5 ± 0.5 mol/mol protein for MGO, however subsequent glycation/carbonylation did not significantly affect PGHS-1 function. Overall, our outcomes allow to better understand the structural aspects of the chemical competition between glycation and acetylation of PGHS-1.
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http://dx.doi.org/10.1016/j.cbi.2016.04.021DOI Listing
June 2016

Higher mitochondrial potential and elevated mitochondrial respiration are associated with excessive activation of blood platelets in diabetic rats.

Life Sci 2016 Mar 9;148:293-304. Epub 2016 Feb 9.

Department of Haemostasis and Haemostatic Disorders, Medical University of Lodz, Mazowiecka 6/8, 92-215 Lodz, Poland.

Aims: The high glucose concentration observed in diabetic patients is a recognized factor of mitochondrial damage in various cell types. Its impact on mitochondrial bioenergetics in blood platelets remains largely vague. The aim of the study was to determine how the metabolism of carbohydrates, which has been impaired by streptozotocin-induced diabetes may affect the functioning of platelet mitochondria.

Materials And Methods: Diabetes was induced in Sprague Dawley rats by intraperitoneal injection of streptozotocin. Platelet mitochondrial respiratory capacity was monitored as oxygen consumption (high-resolution respirometry). Mitochondrial membrane potential was assessed using a fluorescent probe, JC-1. Activation of circulating platelets was monitored by flow cytometry measuring of the expressions of CD61 and CD62P on a blood platelet surface. To determine mitochondrial protein density in platelets, Western Blot technique was used.

Key Findings: The results indicate significantly elevated mitochondria mass, increased mitochondrial membrane potential (ΔΨm) and enhanced respiration in STZ-diabetic animals, although the respiration control ratios appear to remain unchanged. Higher ΔΨm and elevated mitochondrial respiration were closely related to the excessive activation of circulating platelets in diabetic animals.

Significance: Long-term diabetes can result in increased mitochondrial mass and may lead to hyperpolarization of blood platelet mitochondrial membrane. These alterations may be a potential underlying cause of abnormal platelet functioning in diabetes mellitus and hence, a potential target for antiplatelet therapies in diabetes.
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http://dx.doi.org/10.1016/j.lfs.2016.02.030DOI Listing
March 2016

Quantification of the Blood Platelet Reactivity in the ADP-Induced Model of Non-Lethal Pulmonary Thromboembolism in Mice with the Use of Laser Doppler Flowmetry.

PLoS One 2016 11;11(1):e0146346. Epub 2016 Jan 11.

Department of Haemostasis and Haemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, Lodz, Poland.

Introduction: The paper describes an alternative method for quantification of in vivo ADP-induced thromboembolism. The aim of the studies was to develop a method of quantification which would not require either extravasation or labelling of platelets. Our proposed approach is based on the monitoring of changes of blood flow with the use of laser Doppler flowmetry.

Materials And Methods: Mice of C57Bl strain were used in the study. ADP was injected to the vena cava and blood flow was monitored with the use of a laser Doppler flowmeter in the mesentery. Measurements in platelet-depleted mice, mice pretreated with cangrelor, an ADP receptor antagonist, and eptifibatide, a blocker of fibrinogen binding to GPIIbIIIa, were conducted as the proof-of-concept in the performed experiments. Intravital microscopy and ex vivo imaging of organs was performed to identify the sites of aggregate formation resulting from ADP injection.

Results: The injection of ADP resulted in a dose-dependent reduction of the blood flow in the mesentery. These responses were fully attributable to blood platelet aggregation, as shown by the lack of the effect in platelet-depleted mice, and significantly reduced responses in mice pretreated with cangrelor and eptifibatide. No platelet aggregate formation in mesenteric vessels was revealed by intravital microscopy, while ex vivo imaging showed accumulation of fluorescent labelled platelets in the lung.

Conclusions: Injection of ADP to the venous system results in the formation of platelet aggregates predominantly in the lung. This results in reversible blood flow cessation in peripheral blood vessels. The measurement of this blood flow cessation in the mesentery allows indirect measurement of ADP-induced pulmonary thromboembolism. We suggest that this approach can be useful for in vivo screening for antiplatelet drug candidates.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0146346PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4713441PMC
July 2016

Long-term untreated streptozotocin-diabetes leads to increased expression and elevated activity of prostaglandin H2 synthase in blood platelets.

Platelets 2016 1;27(3):203-11. Epub 2015 Sep 1.

a Department of Haemostasis and Haemostatic Disorders , Chair of Biomedical Sciences, Medical University of Lodz , Lodz , Poland and.

In diabetes-related states of chronic hyperglycaemia elevated concentrations of glucose may alter the functioning of platelet enzymes involved in arachidonic acid metabolism, including prostaglandin H2 synthase (cyclooxygenase) (PGHS, COX). Therefore, the principal aim of this study was to assess the effects of experimental chronic hyperglycaemia on platelet PGHS-1 (COX-1) expression and activity. Blood platelet activation and reactivity were assessed in Sprague-Dawley rats with the 5-month streptozotocin (STZ) diabetes. The PGHS-1 abundance in platelets was evaluated with flow cytometry and Western blotting, while its activity monitored using a high resolution respirometry and the peroxidase fluorescent assay. The production of prostaglandin E2 (PGE2) and thromboxane B2 (TXB2) in platelets were assayed immunoenzymatically. Circulating platelets from diabetic were characterised by increased size, elevated 'priming' and altered reactivity, compared to non-diabetic animals. Both Western blot analysis and flow cytometry revealed significantly elevated expressions of platelet PGHS-1 in STZ-diabetic rats (p < 0.05). We also observed significantly elevated platelet PGHS-1-related arachidonic acid metabolism in diabetic vs. non-diabetic animals, with the use of polarographic (p < 0.05) and total activity assay (p < 0.001). Such increases were accompanied by the elevated production of PGE2 (p < 0.001) and TXB2 (p < 0.05) in diabetic animals. The increased PGHS-1-dependent oxygen consumption and the total activity of PGHS-1 in diabetic animals remained very significant (p < 0.001) also upon adjusting for blood platelet PGHS-1 abundance. Therefore, our results further contribute to the explanation of the increased metabolism of arachidonic acid observed in diabetes.
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http://dx.doi.org/10.3109/09537104.2015.1075492DOI Listing
December 2016

How do the full-generation poly(amido)amine (PAMAM) dendrimers activate blood platelets? Activation of circulating platelets and formation of "fibrinogen aggregates" in the presence of polycations.

Int J Pharm 2016 Apr 28;503(1-2):247-61. Epub 2015 Aug 28.

University of Lodz, Faculty of Biology and Environmental Protection, Department of Thermobiology, Pomorska 141/143, 90-236 Lodz, Poland.

Direct use of poly(amido)amine (PAMAM) dendrimers as drugs may be limited, due to uncertain (cyto)toxicity. Peripheral blood components, which constitute the first line of a contact with administered pharmaceuticals, may become vastly affected by PAMAM dendrimers. The aim of this study was to explore how PAMAMs' polycationicity might affect blood platelet activation and reactivity, and thus trigger various haemostatic events. We monitored blood platelet reactivity in rats with experimental diabetes upon a long-term administration of the unmodified PAMAM dendrimers. In parallel, the effects on blood flow in a systemic circulation was recorded intravitally in mice administered with PAMAM G2, G3 or G4. Compounding was the in vitro approach to monitor the impact of PAMAM dendrimers on blood platelet activation and reactivity and on selected haemostatic and protein conformation parameters. We demonstrated the activating effects of polycations on blood platelets. Some diversity of the revealed outcomes considerably depended on the used approach and the particular technique employed to monitor blood platelet function. We discovered undesirable impact of plain PAMAM dendrimers on primary haemostasis and their prothrombotic influence. We emphasize the need of a more profound verifying of all the promising findings collected for PAMAMs with the use of well-designed in vivo preclinical studies.
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http://dx.doi.org/10.1016/j.ijpharm.2015.08.073DOI Listing
April 2016

Inhibition of cyclooxygenase-2 causes a decrease in coronary flow in diabetic mice. The possible role of PGE2 and dysfunctional vasodilation mediated by prostacyclin receptor.

J Physiol Biochem 2015 Sep 5;71(3):351-8. Epub 2015 May 5.

Department of Haemostasis and Haemostatic Disorders, Chair of Biomedical Sciences, Medical University of Lodz, Lodz, 92-215, Poland,

Several lines of evidence suggest that cyclooxygenase-2 (COX-2) activity can have a beneficial role in the maintenance of vascular tone of the blood vessels in diabetes. Specifically, the increased production of prostacyclin (PGI2) and prostaglandin E2 (PGE2), mediated by COX-2, has been suggested to compensate for decreased synthesis of nitric oxide (NO). The study investigates whether inhibition of COX-2 may reduce the coronary flow in diabetic animals and may also lead to decreased synthesis of prostaglandins. Mice aged 18-20 weeks were used for the study: those with leptin receptor deficiency (db/db) served as a model of diabetes while heterozygous (db/+) mice served as controls. Coronary flow was measured by the Langendorff method, and prostaglandin synthesis by myocardia was assayed in heart perfusates. COX-2 inhibition was found to reduce basal coronary flow in db/db mice but had no effect in db/+ mice. Secretion of PGE2 was found to be higher in db/db mice, while prostacyclin synthesis did not differ. COX-2 inhibition decreased production of both prostaglandins to similar levels in both groups. The use of ONO-1301, a specific agonist for the prostacyclin receptor revealed that vasodilating responses mediated by the receptor were impaired in db/db mice. The expression levels of the receptor in cardiac tissue did not differ between the groups. It is concluded that the increased COX-2 contribution to vasodilation in diabetic animals appears to be partially a result of increased COX-2-dependent synthesis of PGE2 and also may be caused by impaired vasodilation mediated by the prostacyclin receptor.
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http://dx.doi.org/10.1007/s13105-015-0415-yDOI Listing
September 2015

[The assessment of hearing impairment in patients over 60 years of age using hearing aids].

Otolaryngol Pol 2014 Jan-Feb;68(1):25-9. Epub 2013 Jul 5.

Medicus Aparatura i Instrumenty Medyczne Sp. Z o.o. S.K.A.

Objective: To assess the hearing impairment in people over 60 years old using hearing aids. This was a single-center study, but it is planned to extend it further to the whole country.

Materials And Methods: The study was focused on patients with hearing aids. During the assessment 57 people were included in the observation in order to control the status of their hearing loss and benefit from traditional hearing aids as well as the possibility to apply the auditory implants in case of a little benefit from hearing aids. The otoscopy and pure tone audiometry were performed as well as the questionnaires on demographic and epidemiological data of patients were collected as well as the quality of their life with hearing aids was subjectively assessed.

Results: The results show that 91% of patients have sensorineural hearing loss (SHL), the remaining 9%--severe mixed hearing loss. Severe SHL was found in 22 patients, the moderate hearing loss was observed in 37%, and the profound SHL was the case in 5 patients. Minimal SHL was observed in 7% of patients (n=4). More than 73% of the study subjects were male (n=38). The average age of the patients who completed the survey was 74 years old. Thirty-five patients used their hearing aid over 3 years and less than 70% of them used it every day all day. Hearing aid was not actively used by 10 patients. Over the last year 51.92% of the patients underwent a hearing examination.

Conclusions: The bone anchored hearing aid was suggested to 2% of subjects and the cochlear implant was offered to 10 patients. The data analysis shows the need to educate and inform the elderly about alternative methods of hearing loss treatment.
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http://dx.doi.org/10.1016/j.otpol.2013.07.001DOI Listing
November 2015

COX-2-derived prostaglandins do not contribute to coronary flow regulation in diabetic rats: distinct secretion patterns of PGI2 and PGE2.

Eur J Pharmacol 2013 Jan 28;700(1-3):86-92. Epub 2012 Dec 28.

Department of Haemostasis and Haemostatic Disorders, Chair of Laboratory Diagnostics, Medical University of Lodz, Central Veterans' Hospital, Lodz, Poland.

The role of cyclooxygenase-2 (COX-2) in restoring the functions of impaired endothelium is attracting considerable attention, notably the function of COX-2-derived vasodilatory prostaglandins is disputed in the context of the regulation function in the impaired vascular beds. We have examined the hypothesis that COX-2 activity contributes more to vasodilation in hyperglycemic animals than in healthy counterparts, and that COX-2 derived vasodilatory prostaglandins (PGI(2) and PGE(2)) are responsible for this effect. Using the Langendorff heart perfusion system, the effects of COX-2 inhibition were monitored on both basal and bradykinin-induced coronary flows in Sprague-Dawley rats given 8-week streptozotocin-induced diabetes and in age-matched controls (n=15). Secretions of PGI(2) and PGE(2), both total and the COX-2 dependent pools, have also been compared. The selective COX-2 inhibitor, N-[2-(cyclohexyloxy)-4-nitrophenyl]-methanesulfonamide (NS-398), had no effect on coronary flow in the diabetic group of animals. Thus, the compensatory role of COX-2 in regulation of vascular tone in experimental diabetes found in other experimental models was not confirmed. However, COX-2 activity significantly contributed to PGI(2) synthesis in healthy rats, with prostacyclin secretion being two-fold decreased by NS-398. Contrary to our hypothesis, neither prostacyclin nor PGE(2) production differed between the experimental groups under the basal conditions. Bradykinin had no effect on the secretion of PGI(2) in either group, but increased PGE(2) synthesis in healthy animals, although not in the streptozotocin group. PGE(2) production in response to bradykinin was COX-2-dependent in control animals. We conclude that, in rats with 8-week streptozotocin-induced diabetes, the activity of COX-2 in coronary vasculature is not significantly enhanced.
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http://dx.doi.org/10.1016/j.ejphar.2012.12.026DOI Listing
January 2013

[Nitroxides as antioxidants - possibilities of their application in chemoprevention and radioprotection].

Postepy Hig Med Dosw (Online) 2011 Feb 2;65:46-54. Epub 2011 Feb 2.

Zakład Badań Struktur Biopolimerów, Katedra Biofizyki Molekularnej, Uniwersytet Łódzki.

Nitroxides as stabile organic radicals were used initially as spin labels in spectroscopy of electron paramagnetic resonance (EPR) with respect to parameters such as pH of an intercellular environment, oxygenation of cells and tissues, fluidity of biological membranes, conformational state and topography of proteins. Nitroxides have also been used in biology and medicine as contrast agents in magnetic resonance imaging (MRI). When their antioxidant activities were discovered, an era of research on the potential utility of these agents began. Nitroxides can modulate the redox state of the cell by participation in oxidation/reduction reactions. Therefore, they are extensively examined in various models of oxidative stress. The antioxidant effect of nitroxides is a result of their ability to catalyze dismutation of superoxide radical (superoxide dismutase-like activity), inhibit lipid peroxidation, prevent Fenton and Haber-Weiss reactions by oxidation of transition metal ions to a higher oxidative state, and confer catalase-like activity on heme proteins. In the present paper the antioxidative mechanisms of nitroxides are presented. The relation between structure, function and the rate of nitroxide reduction inside cells and tissues is also presented. The application of nitroxides in chemoprevention and radioprotection is discussed.
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http://dx.doi.org/10.5604/17322693.932256DOI Listing
February 2011