It is now widely accepted that white adipose tissue (WAT) is not merely a fuel storage organ, but also a key component of metabolic homoeostatic mechanisms. Apart from its major role in lipid and ...glucose metabolism, adipose tissue is also involved in a wide array of other biological processes. The hormones and adipokines, as well as other biologically active agents released from fat cells, affect many physiological and pathological processes. WAT is neither uniform nor inflexible because it undergoes constant remodelling, adapting the size and number of adipocytes to changes in nutrients’ availability and hormonal milieu. Fat depots from different areas of the body display distinct structural and functional properties and have disparate roles in pathology. The two major types of WAT are visceral fat, localized within the abdominal cavity and mediastinum, and subcutaneous fat in the hypodermis. Visceral obesity correlates with increased risk of insulin resistance and cardiovascular diseases, while increase of subcutaneous fat is associated with favourable plasma lipid profiles. Visceral adipocytes show higher lipogenic and lipolytic activities and produce more pro‐inflammatory cytokines, while subcutaneous adipocytes are the main source of leptin and adiponectin. Moreover, adipose tissue associated with skeletal muscles (intramyocellular and intermuscular fat) and with the epicardium is believed to provide fuels for skeletal and cardiac muscle contraction. However, increased mass of either epicardial or intermuscular adipose tissue correlates with cardiovascular risk, while the presence of the intramyocellular fat is a risk factor for the development of insulin resistance. This review summarizes results of mainly human studies related to the differential characteristics of various WAT depots.
The concept of biomaterials has evolved from one of inert mechanical supports with a long‐term, biologically inactive role in the body into complex matrices that exhibit selective cell binding, ...promote proliferation and matrix production, and may ultimately become replaced by newly generated tissues in vivo. Functionalization of material surfaces with biomolecules is critical to their ability to evade immunorecognition, interact productively with surrounding tissues and extracellular matrix, and avoid bacterial colonization. Antibody molecules and their derived fragments are commonly immobilized on materials to mediate coating with specific cell types in fields such as stent endothelialization and drug delivery. The incorporation of growth factors into biomaterials has found application in promoting and accelerating bone formation in osteogenerative and related applications. Peptides and extracellular matrix proteins can impart biomolecule‐ and cell‐specificities to materials while antimicrobial peptides have found roles in preventing biofilm formation on devices and implants. In this progress report, we detail developments in the use of diverse proteins and peptides to modify the surfaces of hard biomaterials in vivo and in vitro. Chemical approaches to immobilizing active biomolecules are presented, as well as platform technologies for isolation or generation of natural or synthetic molecules suitable for biomaterial functionalization.
Functionalization of material surfaces with biomolecules is critical to evade immunorecognition, interact with surrounding tissues and avoid bacterial colonization. The use of antibody molecules, growth factors, extracellular matrix proteins and peptides to promote endothelialization, mediate osteogeneration, impart cell‐binding or prevent biofilm formation on materials is described. Recombinant protein production and chemical strategies are also discussed.
Cardiovascular disease (CVD) is a major cause of morbidity and mortality worldwide. Innovative, more stringent diagnostic and prognostic biomarkers and effective treatment options are needed to ...lessen its burden. In recent years, microRNAs have emerged as master regulators of gene expression – they bind to complementary sequences within the mRNAs of their target genes and inhibit their expression by either mRNA degradation or translational repression. microRNAs have been implicated in all major cellular processes, including cell cycle, differentiation and metabolism. Their unique mode of action, fine‐tuning gene expression rather than turning genes on/off, and their ability to simultaneously regulate multiple elements of relevant pathways makes them enticing potential biomarkers and therapeutic targets. Indeed, cardiovascular patients have specific patterns of circulating microRNA levels, often early in the disease process. This article provides a systematic overview of the role of microRNAs in the pathophysiology, diagnosis and treatment of CVD.
The aim of this study was to examine the effects of the hypolipemic drug fenofibrate (FF) and aging on the expression of factors/enzymes involved in brown adipose tissue (BAT) function and browning ...of white adipose tissue epididymal (eWAT) and subcutaneous (sWAT) depots. Young-adult and old male Wistar rats were fed standard chow (control) or supplemented with 0.1% or 0.5% FF for 30 days. Tissue samples were analysed for gene expression and protein content, and stained with Oil Red O or hematoxylin and eosin. In BAT of young rats, 0.5% FF increased only Cbp/p300 interacting transactivator with Glu/Asp rich carboxy-terminal domain 1 (CITED1) protein content and Fgf21 and Gpr109A mRNA expression. The expression of oxidative metabolism related genes (Pgc1α, Cpt1b, Mcad) decreased after 0.5% FF. In BAT of old rats, FF did not affect UCP1 and CITED1 content and had little effect on gene expression. Oil Red O staining of BAT revealed no changes in lipid droplet area upon treatment in either age group. In eWAT of young rats, 0.1FF elevated UCP1 protein content and Ucp1, Pgc-1α, and Mcad expression, whereas 0.5% FF increased PPARα content and Pgc-1α, Cpt1b, Mcad, and Gpr109A levels. In eWAT of old rats, only 0.1FF increased Pgc1α and Mcad expression. In both age groups median cell area of eWAT adipocytes was reduced after 0.5% FF. In sWAT Ucp1 gene expression was very low and UCP1 protein was undetectable. FF upregulated Ucp1, Cited1, Eva1, and Cpt1b expression in sWAT of young rats, with diminished effects in old rats. In both age groups 0.5% FF increased Fgf21 expression in sWAT. Median cell area of sWAT adipocytes decreased only in young rats treated with 0.5% FF. Our results reveal that fenofibrate differentially affects gene expression in BAT, with diminished effects in old compared to young rats. In WAT of young rats FF modestly stimulates the expression of factors/enzymes involved in lipid oxidative metabolism and browning. Aging reduces both these effects. Gpr109A may present a novel gene target upregulated by FF in BAT and eWAT.
The metabolic effects of short-term calorie restriction (SCR) and subsequent refeeding were compared in different white adipose tissue (WAT) depots of young (5-month old) and old (24-month) male ...Wistar rats. The animals were subjected to a 40% calorie restricted diet (i.e. 40% lower food supply than of control rats) for 30 days, and then re-fed for 0, 2, or 4 days. WAT samples from perirenal (pWAT), epididymal (eWAT), and subcutaneous (sWAT) depots were analysed for the enzymatic activities of ATP-citrate lyase (ACL), fatty acid synthase (FAS), and glucose-6-phosphate dehydrogenase (G6PD). The total WAT mass almost doubled in old rats, however, aging did not alter the relative proportions of the major regional fat depots. Serum leptin concentration was prominently higher in old rats, in which SCR resulted in less suppression of leptin level than in young animals, whereas refeeding increased leptin concentration in young, but not old, rats. In young rats refeeding elevated leptin gene expression only in pWAT, while in old rats the expression was induced first in eWAT, and later in pWAT. A prominent age-related decrease of ACL and FAS activities, but not of G6PD activity, was found in all the studied WAT depots. In young control rats, ACL activity was highest in pWAT, FAS activity was similar in all WAT depots, and G6PD activity was lowest in eWAT. In old rats, the enzymatic activities were lower in eWAT than in the other depots. The patterns of response to SCR and refeeding varied by age and WAT location. SCR stimulated ACL activity in pWAT but not in other depots of young rats, while FAS activity in pWAT and sWAT did not change in young and decreased in the old animals. Among the studied depots, pWAT was most responsive to refeeding in both age groups. In conclusion, SCR in old rats, as compared to the young, may be accompanied by reduced 'rebound effect' upon returning to unrestricted diet.
Proton exchange membrane fuel cells (PEMFCs) are numbered among low-temperature cells. Their operating temperature reaches 120°C, whereas their efficiency amounts to ca. 40%. These cells are most ...often used for the batteries for portable devices, low and high power generators, stationary power plants and car drives. The PEMFCs are composed of the membrane, electrodes at both sides and bipolar plates, also termed interconnectors. The main aim of the present study was to investigate the sintered stainless steels in simulated environments of a PEM fuel cells for bipolar plates. The ferritic (434L) and austenitic (316L) stainless steels were examined. The corrosion properties were examined in 0.1 mol dm
Na
SO
ppmF-(pH= 1; 3; 5) at 80°C.
Ogniwa paliwowe z membrana protonowymienna sa jednym, z niskotemperaturowych ogniw. Ich temperatura pracy wynosi 120°C, a sprawnosc dochodzi do 40%. Tego typu ogniwa sa najczesciej uzywane jako generatory do urzadzen przenosnych, małych i srednich stacjonarnych elektrowni i do napedu samochodowego. Ogniwa PEMFC (Proton Exchange Membrane Fuel Cell) składaja sie z membrany, elektrod po obu jej stronach oraz okładek, nazywanych tez interkonektorami. Głównym celem niniejszej pracy było zbadanie spiekanych stali nierdzewnych przeznaczonych na okładki, w symulowanych srodowiskach ogniw paliwowych PEMFC. Badano stal ferrytyczna (434L) oraz austenityczna (316L). Odpornosc korozyjna stali badano w 0.1 mol dm
Na
SO
+2 ppmF- (pH= 1; 3; 5) w temperaturze 80°C.
A two-axis gimbal system can be used for stabilizing platform equipped with observation system like cameras or different measurement units. The most important advantageous of using a gimbal ...stabilization is a possibility to provide not disturbed information or data from a measurement unit. This disturbance can proceed from external working conditions. The described stabilization algorithm of a gimbal system bases on a regulator with a feedback loop. Steering parameters are calculated from quaternion transformation angular velocities received from gyroscopes. This data are fed into the input of Proportional Integral Derivative (PID) controller. Their input signal is compared with earned value in the feedback loop. The paper presents the way of increasing the position’s accuracy by getting it in the feedback loop. The data fusion from a positioning sensor and a gyroscope results in much better accuracy of stabilization.
In degenerative disorders of the CNS an immune system involvement in the pathological process is postulated. The MPTP model of Parkinson's disease seem to be a good model for studying an inflammation ...following toxic neurodegeneration. In this model, microglial and astroglial reactions were previously found around impaired neurons. In the present work we showed an immune reaction, including lymphocytic infiltration of CD4+ and CD8+ T cells in the substantia nigra and striatum and elevated MHC class I and II antigens expression on microglia. Many activated lymphocytes were present, showing increased LFA-1 and CD44 antigen expression. We found also that ICAM-1 expression increased on the endothelium and appeared on microglia in the injured regions. Treatment with dexamethasone inhibited T-cell infiltration and MHC class II expression, lessened the glial reaction, and also diminished neuronal impairment. These findings suggest that an immune mechanism may contribute to the neuronal damage following MPTP administration.
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