The mistery of stroke: the role of calcium and magnesium in the penumbra neurons' death

Penumbra zone is localized on the border of ischaemic focus. Low cerebral blood flow allows the neurons to survive but it is insufficient for normal processes. Calcium ions play a significant role in the development of apoptosis within the neurons in penumbra. Intracellular calcium "swiches on" releasing cytochrom c from mitochondria - which is an important component of apoptosis. Extracellular calcium binds to the specific receptor localized on the cell membrane and activates antiapoptotic pathway which helps the cell to survive. Magnesium, in contrast to calcium ions, also excerts an antiapoptotic effect in the intracellular localization. Inhibition of glutamate (aminoacid which takes part in excitotoxicy) had brought the hope that magnesium could have been used in the stroke treatment. Unfortunately huge clinical trial with magnesium early administration in the acute ischemic stroke did not show the significant benefits of magnesium treatment. Future studies should be focused on recognition of molecular mechanism of magnesium and calcium ions acting in the excitotoxicy and apoptosis of the penumbra neurons

Matrix Metalloproteinases as a Pleiotropic Biomarker in Medicine and Biology

The group of matrix metalloproteinases (MMPs), calcium- and zinc-dependent proteolytic enzymes, is responsible for extracellular protein degradation. Acting together, supported by intracellular processes they are able to digest any phys- iological extracellular protein. However, the biochemistry of extracellular matrix (ECM) is very complex, and prote- olytic enzymes located in this compartment exert numerous pleiotropic e ects beyond the characteristic for the degrada- tion of structural elements. erefore, MMPs are involved into several physiological and pathological processe

Antioxidant Potential of Propolis, Bee Pollen, and Royal Jelly: Possible Medical Application

Honeybees products comprise of numerous substances, including propolis, bee pollen, and royal jelly, which have long been known for their medicinal and health-promoting properties. Their wide biological effects have been known and used since antiquity. Bee products are considered to be a potential source of natural antioxidants such as flavonoids, phenolic acids, or terpenoids. Nowadays, the still growing concern in natural substances capable of counteracting the effects of oxidative stress underlying the pathogenesis of numerous diseases, such as neurodegenerative disorders, cancer, diabetes, and atherosclerosis, as well as negative effects of different harmful factors and drugs, is being observed. Having regarded the importance of acquiring drugs from natural sources, this review is aimed at updating the current state of knowledge of antioxidant capacity of selected bee products, namely, propolis, bee pollen, and royal jelly, and of their potential antioxidant-related therapeutic applications. Moreover, the particular attention has been attributed to the understanding of the mechanisms underlying antioxidant properties of bee products. The influence of bee species, plant origin, geographic location, and seasonality as well as type of extraction solutions on the composition of bee products extracts were also discussed

The influence of silver nanoparticles on the process of epithelial transition in the context of cancer metastases

Background Exposure to nanoparticles (NPs) can occur in a variety of occupational situations. Ultrafine particles of natural and anthropological origin toxicity has been described in epidemiological studies. Meanwhile, the risks associated with NPs exposure are not comprehensively assessed. A wide spectrum of NPs toxicity has been demonstrated, mainly through the induction of oxidative stress and inflammatory mediators. Among the newly described mechanisms of NPs toxicity is the induction of fibrosis via the epithelial-mesenchymal transition (EMT), which is also a key mechanism of cancer metastasis. The effect of NPs on EMT in the context of metastasis has not been sufficiently described so far, and the results of studies do not allow for the formulation of unambiguous conclusions. Therefore, the aim of the work was to determine the biological activity of silver NPs against MDA-MB-436 triple-negative breast cancer cells. Material and Methods Exposure to nanoparticles (NPs) can occur in a variety of occupational situations. Ultrafine particles of natural and anthropological origin toxicity has been described in epidemiological studies. Meanwhile, the risks associated with NPs exposure are not comprehensively assessed. A wide spectrum of NPs toxicity has been demonstrated, mainly through the induction of oxidative stress and inflammatory mediators. Among the newly described mechanisms of NPs toxicity is the induction of fibrosis via the epithelial-mesenchymal transition (EMT), which is also a key mechanism of cancer metastasis. The effect of NPs on EMT in the context of metastasis has not been sufficiently described so far, and the results of studies do not allow for the formulation of unambiguous conclusions. Therefore, the aim of the work was to determine the biological activity of silver NPs against MDA-MB-436 triple-negative breast cancer cells. Results Silver nanoparticles (AgNPs) cause a statistically significant increase in relative expression of all tested mesenchymal EMT markers – cadherin 2, vimentin, matrix metalloproteinase 2 and matrix metalloproteinase 9. At the same time, reduction of epithelial cadherin 1 expression was observed. The level of MDA-MB-436 migration and TGF-beta 1 secretion was slighty increased in AgNPs-treated cells, with no influence on invasion potential. Conclusions Potentially prometastatic effect of AgNPs encourages further work on the safety of nanomaterials. Med Pr Work Health Saf. 2023;74(6):541–8