Estradiol as the Trigger of Sirtuin-1-Dependent Cell Signaling with a Potential Utility in Anti-Aging Therapies

Aging entails the inevitable loss of the structural and functional integrity of cells and tissues during the lifetime. It is a highly hormone-dependent process; although, the exact mechanism of hormone involvement, including sex hormones, is unclear. The marked suppression of estradiol synthesis during menopause suggests that the hormone may be crucial in maintaining cell lifespan and viability in women. Recent studies also indicate that the same may be true for men. Similar anti-aging features are attributed to sirtuin 1 (SIRT1), which may possibly be linked at the molecular level with estradiol. This finding may be valuable for understanding the aging process, its regulation, and possible prevention against unhealthy aging. The following article summarizes the initial studies published in this field with a focus on age-associated diseases, like cancer, cardiovascular disease and atherogenic metabolic shift, osteoarthritis, osteoporosis, and muscle damage, as well as neurodegenerative and neuropsychiatric diseases

Inhibition of glutamate receptors reduces the homocysteine-induced whole blood platelet aggregation but does not affect superoxide anion generation or platelet membrane fluidization

Homocysteine (Hcy) is an excitotoxic amino acid. It is potentially possible to prevent Hcy-induced toxicity, including haemostatic impairments, by antagonizing glutaminergic receptors. Using impedance aggregometry with arachidonate and collagen as platelet agonists, we tested whether the blockade of platelet NMDA (N-methyl-D-aspartate), AMPA (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) and kainate receptors with their inhibitors: MK-801 (dizocilpine hydrogen maleate, [5R,10S]-[+]-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine), CNQX (7-nitro-2,3-dioxo-1,4-dihydroquinoxaline-6-carbonitrile) and UBP-302 (2-{[3-[(2S)-2-amino-2-carboxyethyl]-2,6-dioxo-3,6-dihydropyrimidin 1(2H)-yl]methyl}benzoic acid) may hamper Hcy-dependent platelet aggregation. All the tested compounds significantly inhibited Hcy-augmented aggregation of blood platelets stimulated either with arachidonate or collagen. Hcy stimulated the generation of superoxide anion in whole blood samples in a concentration-dependent manner; however, this process appeared as independent on ionotropic glutamate receptors, as well as on NADPH oxidase and protein kinase C, and was not apparently associated with the extent of either arachidonate- or collagen-dependent platelet aggregation. Moreover, Hcy acted as a significant fluidizer of surface (more hydrophilic) and inner (more hydrophobic) regions of platelet membrane lipid bilayer, when used at the concentration range from 10 to 50 µmol/l. However, this effect was independent on the Hcy action through glutamate ionotropic receptors, since there was no effects of MK-801, CNQX or UBP-302 on Hcy-mediated membrane fluidization. In conclusion, Hcy-induced changes in whole blood platelet aggregation are mediated through the ionotopic excitotoxic receptors, although the detailed mechanisms underlying such interactions remain to be elucidated

Mechanism of action of cytostatic drugs used in neurology

The aim of this review is the presentation of molecular mechanisms of action of cytostatic drugs used in the therapy of neurological disorders, mostly of multiple sclerosis (MS). From many years cytostatics like mitoxantrone, cyclophosphamide, cladribine and methotrexate were used in the MS clinical trials. So far only mitoxantrone has been approved by FDA for the treatment of progressive MS. The other cytostatics are still studied in clinical trials, the main problem with their approval for human therapy are their numerous side effects. So far those drugs are mostly used in oncology and haematology where the usage of this type of drugs is better justified. Now there are many studies leading to better understanding of mechanisms of action of cytostatics at the cellular and subcellular level. Mitoxantrone induces apoptosis and reduce the population of inflammatory egzocells capable to initiate demyelination in the central nervous system (CNS). At the molecular level mitoxantrone damages genome of inflammatory cells by inhibition of activity of topoisomerase II (TOP II) or direct interaction with DNA structure. Cyclophosphamide is a cytostatic acting mainly on dividing cells, in which it alkylates DNA and interferes with replication and cell apoptosis. Methotrexate inhibits activity of dehydrofolate reductase what leads to disturbance of replication and blocks phase S of the cell cycle in leukocytes. Cladribine is an antagonist of transcription. The detailed analysis of these mechanisms may lead to diminishing of the level of their side effects and to increase of their therapeutic potential, also in neurological therapy.Celem niniejszej pracy jest przedstawienie molekularnych mechanizmów działania cytostatyków stosowanych w próbach terapii niektórych chorób neurologicznych, głównie stwardnienia rozsianego (SM). Od wielu lat w terapii tego schorzenia próbuje się wykorzystywać takie cytostatyki, jak mitoksantron, cyklofosfamid, metotreksat i kladrybina. W chwili obecnej jedynym lekiem z tej grupy zatwierdzonym przez FDA do leczenia postępującego SM jest mitoksantron. Pozostałe cytostatyki wciąż poddawane są badaniom, a główny problem we wprowadzeniu ich do terapii neurologicznej stanowią liczne efekty uboczne. Leki te wykorzystywane są głównie w onkologii i hematologii, gdzie stosowanie tego typu leków jest bardziej uzasadnione. W chwili obecnej prowadzone są liczne badania zmierzające do lepszego poznania mechanizmów działania cytostatyków na poziomach komórkowym i subkomórkowym. Przyjmuje się, że mitoksantron indukuje apoptozę, co zmniejsza pulę komórek zapalnych zdolnych do wywoływania demielinizacji w obrębie ośrodkowego układu nerwowego (OUN). Na poziomie molekularnym mechanizm jego działania polega na uszkodzeniu genomu tych komórek poprzez hamowanie aktywności topoizomerazy II (TOPII) lub bezpośrednie wbudowywanie się w strukturę ich DNA. Cyklofosfamid jest cytostatykiem działającym w głównej mierze na komórki dzielące się, w których alkiluje on DNA, co indukuje zaburzenia replikacji oraz apoptozę tych komórek. Działanie lecznicze metotreksatu wynika ze zdolności do hamowania aktywności reduktazy dehydrofolianowej. W ten sposób zaburzony zostaje metabolizm zasad azotowych prowadzący do zaburzeń replikacji i bloku fazy S cyklu komórkowego leukocytów. Kladrybina działa jako antagonista procesu transkrypcji. Dokładne poznanie mechanizmów działania prezentowanych leków może doprowadzić do zmniejszenia nasilenia ich efektów ubocznych oraz do zwiększenia ich potencjału leczniczego, również w terapii neurologicznej

INFLUENCE OF THE PATH TYPE ON SELECTED TECHNOLOGICAL EFFECTS IN THE TROCHOIDAL MILLING

Article presents basic informations about machining materials in hardened state – especially it describes method so called hard milling. Paper talk about strategies and methods in hard milling, describes trochoidal milling, its advantages and disadvantages. Also presents research methodology and effects which concerned determination of tool path impact on selected technological effects after trochoidal milling of the groove

The Association of Oxidative and Antioxidant Potential with Cardiometabolic Risk Profile in the Group of 60- to 65-Year-Old Seniors from Central Poland

Pathogenesis of cardiovascular diseases is caused by, inter alia, oxidative stress. On the other hand, cardiovascular risk factors may cause redox imbalance. The pathological pathways between those components are to be determined. In the group comprised of 300 sex-matched subjects, we evaluated a number of cardiovascular risk factors: blood pressure, body mass, lipids, glucose, homocysteine, uric acid, von Willebrand factor (vWF), VCAM-1 and ICAM-1. The presence of cardiovascular diseases and drugs for their treatment were examined. Secondly, we assessed total antioxidative status (TAS), total oxidative status (TOS) and other markers of oxidative stress. TAS was inversely related to LDL cholesterol. TOS was positively associated with BMI and female sex, but negatively associated with the use of angiotensin II receptor antagonists. Plasma lipid peroxides concentration was positively related to ICAM-1 and presence of stroke, whereas platelet lipid peroxides were positively associated with vWF. Platelets proteins thiol groups were in a positive relationship with vWF, but in a negative relationship with uric acid and diagnosed lipid disorders. Both free thiol and amino groups were positively associated with plasma glucose. Platelets free amino groups were related to platelets count. Superoxide generation by blood platelets (both with and without homocysteine) was positively connected to glucose level. Among women, oxidative markers appear to be more related to glucose level, whereas among men they are related to body mass indices. TAS, TOS and oxidative markers are largely related to modifiable cardiovascular risk factors such as body mass, and intake of drugs such as angiotensin II receptor blockers. Plasma and platelet oxidation markers appear to be especially associated with glucose concentration. The presented analyses unanimously indicate strong connections between cardiovascular risk factors and redox potential and specify how cardiometabolic interventions may counter-balance oxidative stress

Influence of the Trochoidal Tool Path on Quality Surface of Groove Walls

The article presents the results of machining materials in hardened state. In the paper, different trochoidal tool paths are compared with each other and with the conventional milling. The results of measurements show the relationship between tool path, roughness and waviness of grooves wall. The paper also presents pictures of grooves which were made. These results provide comparative material useful in the choice of the best milling strategy to the cutting process

Platelet and Red Blood Cell Counts, as well as the Concentrations of Uric Acid, but Not Homocysteinaemia or Oxidative Stress, Contribute Mostly to Platelet Reactivity in Older Adults

Purpose. The goal of this study was to estimate the hierarchical contribution of the most commonly recognized cardiovascular risk factors associated with atherogenesis to activation and reactivity of blood platelets in a group of men and women at ages 60-65. Methods. Socioeconomic and anthropometric data were taken from questionnaires. Blood morphology and biochemistry were measured with standard diagnostic methods. Plasma serum homocysteine was measured by immunochemical method. Plasma concentrations of VCAM, ICAM, total antioxidant status, and total oxidant status were estimated with commercial ELISA kits. Markers of oxidative stress of plasma and platelet proteins (concentrations of protein free thiol and amino groups) and lipids (concentrations of lipid peroxides) and generation of superoxide anion by platelets were measured with colorimetric methods. Platelet reactivity was estimated by impedance aggregometry with arachidonate, collagen, and ADP as agonists. Expression of selectin-P and GPIIb/IIIa on blood platelets was tested by flow cytometry. Results. Platelet aggregation associated significantly negatively with HGB and age and significantly positively with PLT, MPV, PCT, PDW, and P-LCR. When platelet reactivity (“cumulative platelet reactivity_aggregation”) was analyzed in a cumulated manner, the negative association with serum concentration of uric acid (Rs=−0.169, p=0.003) was confirmed. Multivariate analysis revealed that amongst blood morphological parameters, platelet count, plateletcrit, and number of large platelets and uric acid are the most predictive variables for platelet reactivity. Conclusions. The most significant contributors to platelet reactivity in older subjects are platelet morphology, plasma uricaemia, and erythrocyte morphology

Protein disulfide isomerase-A1 regulates intraplatelet reactive oxygen speciesthromboxane A<SUB>2</SUB>-dependent pathway in human platelets

BACKGROUND: Platelet‐derived protein disulfide isomerase 1 (PDIA1) regulates thrombus formation, but its role in the regulation of platelet function is not fully understood. AIMS: The aim of this study was to characterize the role of PDIA1 in human platelets. METHODS: Proteomic analysis of PDI isoforms in platelets was performed using liquid chromatography tandem mass spectometry, and the expression of PDIs on platelets in response to collagen, TRAP‐14, or ADP was measured with flow cytometry. The effects of bepristat, a selective PDIA1 inhibitor, on platelet aggregation, expression of platelet surface activation markers, thromboxane A(2) (TxA(2)), and reactive oxygen species (ROS) generation were evaluated by optical aggregometry, flow cytometry, ELISA, and dihydrodichlorofluorescein diacetate‐based fluorescent assay, respectively. RESULTS: PDIA1 was less abundant compared with PDIA3 in resting platelets and platelets stimulated with TRAP‐14, collagen, or ADP. Collagen, but not ADP, induced a significant increase in PDIA1 expression. Bepristat potently inhibited the aggregation of washed platelets induced by collagen or convulxin, but only weakly inhibited platelet aggregation induced by TRAP‐14 or thrombin, and had the negligible effect on platelet aggregation induced by arachidonic acid. Inhibition of PDIA1 by bepristat resulted in the reduction of TxA(2) and ROS production in collagen‐ or thrombin‐stimulated platelets. Furthermore, bepristat reduced the activation of αIIbβ3 integrin and expression of P‐selectin. CONCLUSIONS: PDIA1 acts as an intraplatelet regulator of the ROS‐TxA(2) pathway in collagen‐GP VI receptor‐mediated platelet activation that is a mechanistically distinct pathway from extracellular regulation of αIIbβ3 integrin by PDIA3