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Blood-Brain Barrier and Exercise – a Short Review

100%

Nierwińska K., Malecka E., Chalimoniuk M., Żebrowska A., Langfort J.

Journal of Human Kinetics

2008

vol. 19

83-92

Blood-brain barier (BBB) segregates central nervous system (CNS) from the circulating blood. BBB is formed by the brain capillary endothelial cells with complex tight junctions between them as well as by astrocytes and pericytes. BBB is responsible for transport of selected chemicals into and out of the CNS as well as for its protection from fluctuations in plasma composition following meals, during exercise and from circulating agents such as neurotransmitters, xenobiotics and other potentially harmful substances capable to disturb neural function. BBB may be compromised during CNS injury, infection, fever and in some nerodegenerative diseases. The increase of BBB permeability was observed also during exercise as documented by changes of plasma S-100 protein levels, used as a peripheral marker of BBB integrity. Marked change in BBB integrity during exercise may disturb normal brain function and contribute to the development of central fatigue. Moreover, serum S-100β may indicate level of injury in individuals suffering brain injuries during sports. There are also data suggesting that acute effect of physical exercise on serum S100β levels may not be related with CNS injury. Further studies to establish whether training and which type of it may modulate BBB permeability are needed.

Fluorometric assay of oleate-activated phospholipase D isoenzyme in membranes of rat nervous tissue and human platelets

75%

Krzystanek M., Trzeciak H. I., Krzystanek E., Małecki A.

2010

vol. 57

issue 3

369-372

Phospholipase D plays a key role in the biosynthesis of phosphatidic acid, a second messenger involved in essential cellular processes. Oleate-activated phospholipase D was the first mammalian phospholipase D isoform to be discovered but is the least known. The study was aimed to test a fluorometric method of assessment of oleate-activated phospholipase D activity in different biological materials. The brain cortex of male Wistar rats, cultured rat brain astrocytes, and human platelets were processed to yield plasmatic membranes for experiments. To assess phospholipase D activity the modified fluorometric method was used. Previously, the method was used only to determine H2O2. In this enzyme-coupled assay phospholipase D activity is monitored indirectly using 10-acetyl-3,7-dihydroxyphenoxazine. First, phospholipase D cleaves exogenous phosphatidylcholine to yield choline and phosphatidic acid. Second, choline is oxidized by choline oxidase to betaine and H2O2. Finally, in the presence of horseradish peroxidase, H2O2 reacts with 10-acetyl-3,7-dihydroxyphenoxazine to generate the highly fluorescent product, resorufin. The concentration of resorufin was measured using excitation and emission at 560 nm and 590 nm, respectively. The proposed optimal parameters of the tested assay are 25 µg of rat brain cortex protein, 50 µg of rat brain astrocyte protein, and 50 µg of human platelet protein in a reaction volume of 200 µL, and 2 min enzymatic reaction at 37°C. The fluorometric method may be applied to assay phospholipase D in different biological materials.

Czy potrzebny jest nowy model neuropoezy?

63%

Rieske P.

Aktualności Neurologiczne

2006

vol. 6

issue 3

164-168

Models of neuropoiesis make it possible to determine at what stage of differentiation are neuronal cells. These models reflect our current knowledge about neuropoiesis, but they have also practical significance. In vitro determination whether neuronal stem cells differentiate to neuronal, astrocytic or oligodendrocytic progenitors is of utmost importance for cellular transplantologists. It seems that the use of progenitor cells and not fully differentiated cells or stem cells provides transplantologists with the greatest chance for therapeutic success: stem cells may choose a differentiation pathway other than planned by transplantologist, while mature cell, e.g. neurons, are quite sensitive to environmental changes. Determination of the progenitor type currently requires screening of expression of markers recognized as specific for particular cell type. Studies conducted for several years indicate that in the case of many markers this strategy is not appropriate. For example, the GFAP protein considered until recently a specific marker of astrocytes is also expressed in some neuronal stem cells. This discovery has led to a considerable chaos in the way cells are being defined. Furthermore, results of studies of the team where the author of this publication belongs indicate that stem cells may show coexpression of glial and neuronal markers. For the neuropoiesis model constructed upon this kind of data, a name “model of suppression of discordant phenotypes'’ has been proposed.

Modele neuropoezy pozwalają określać, na jakim etapie różnicowania znajdują się komórki neuralne. Modele te oddają stan naszej wiedzy o neuropoezie, niemniej mają również znaczenie praktyczne. Stwierdzenie w warunkach in vitro, czy neuralne komórki macierzyste różnicują się do progenitorów neuronalnych, astrocytarnych czy oligodendrocytarnych, jest bardzo ważne dla transplantologów komórkowych. Wydaje się bowiem, że stosowanie właśnie progenitorów, a nie komórek w pełni zróżnicowanych czy komórek macierzystych, daje transplantologom największe szanse na sukces terapeutyczny – komórki macierzyste mogą wybrać szlak różnicowania inny niż planowany przez transplantologa, natomiast komórki dojrzałe, takie jak np. neurony, nie są odporne na zmiany środowiska. Ustalenie, z jakim progenitorem mamy do czynienia, wymaga obecnie określenia ekspresji markerów uznawanych za specyficzne dla danych komórek. Badania prowadzone od kilku lat pokazują jednak, iż w przypadku wielu markerów taka strategia nie jest właściwa. Dla przykładu, białko GFAP uznawane do niedawna za marker astrocytów ulega ekspresji także w niektórych nerwowych komórkach macierzystych. Odkrycie to prowadzi do poważnego zamętu w sposobie definiowania komórek. Ponadto wyniki badań zespołu, do którego należy autor niniejszej publikacji, wskazują, że komórki macierzyste mogą wykazywać koekspresję markerów komórek glejowych i neuronalnych. Dla modelu neuropoezy skonstruowanego w oparciu o tego typu wyniki zaproponowano nazwę: „model supresji niespójnych fenotypów”.

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1 Acta Biochimica Polonica

1 Aktualności Neurologiczne

1 Journal of Human Kinetics

1 2010

1 2008

1 2006

1 Chalimoniuk M.

1 Krzystanek E.

1 Krzystanek M.

1 Langfort J.

1 Malecka E.

1 Małecki A.

1 Nierwińska K.

1 Rieske P.

1 Trzeciak H. I.

1 Żebrowska A.

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Blood-Brain Barrier and Exercise – a Short Review

Fluorometric assay of oleate-activated phospholipase D isoenzyme in membranes of rat nervous tissue and human platelets

Czy potrzebny jest nowy model neuropoezy?