Milos Kostic

Multiple sclerosis and glutamate excitotoxicity

Abstract The previous understanding of multiple sclerosis was solely related to neuroinflammation and its harmful effects; however, countless data indicate the importance of some inflammation-independent, neurodegenerative mechanisms associated with mitochondria malfunction, iron deposition and oxidative stress. Recently, it has been postulated that glutamate excitotoxicity, a phenomenon that takes place when an excessive amount of glutamate overactivates its cellular receptors and induces cell death, could be a missing link between inflammatory and neurodegenerative processes evident in multiple sclerosis. Glutamate is the major excitatory neurotransmitter of the central nervous system, which has been proven to have a central role in a complex communication network established between all residential brain cells, including neurons, astrocytes, oligodendrocytes and microglia. Thus, the disturbance of glutamate homeostasis could affect practically all physiological functions and interactions of brain cells, leading to heterogeneity of pathological events. The understanding of glutamate excitotoxicity as a valid mechanism of central nervous system damage in multiple sclerosis, requires the revision of the current knowledge about a source of elevated extracellular glutamate, glutamate receptor alterations, alterations of glutamate transporters and metabolizing enzymes, as well as molecular mechanism of excitotoxic damage.

IL-17 and glutamate excitotoxicity in the pathogenesis of multiple sclerosis.

Immunoinflammatory‐mediated demyelination, the main pathological feature of multiple sclerosis (MS), is regularly accompanied by neurodegenerative processes, mostly in the form of axonal degeneration, which could be initiated by glutamate excitotoxicity. In the current study, the relationship between Th17‐mediated inflammatory and excitotoxic events was investigated during an active phase of MS. Cerebrospinal fluid (CSF) of patients with MS and control subjects was collected, and IL‐17A and glutamate levels were determined. IL‐17A level was significantly higher in patients with MS; whereas no statistically significant changes in glutamate concentrations were found. There was a direct correlation between IL‐17A and glutamate levels; IL‐17A levels were also associated with the neutrophil expansion in CSF and blood–brain barrier disruption. However, IL‐17A level and the number of neutrophils tended to fall with disease duration. The results suggest that Th17 cells might enhance and use glutamate excitotoxicity as an effector mechanism in the MS pathogenesis. Furthermore, Th17 immune response, as well as neutrophils, could be more important for MS onset rather than further disease development and progression, what could explain why some MS clinical trials, targeting Th17 cells in the later stage of the disease, failed to provide any clinical benefit.

The role of glutamate and its receptors in multiple sclerosis

Abstract Glutamate is an excitatory neurotransmitter of the central nervous system, which has a central role in a complex communication network established between neurons, astrocytes, oligodendrocytes, and microglia. Multiple abnormal triggers such as energy deficiency, oxidative stress, mitochondrial dysfunction, and calcium overload can lead to abnormalities in glutamate signaling. Thus, the disturbance of glutamate homeostasis could affect practically all physiological functions and interactions of brain cells, leading to excitotoxicity. Excitotoxicity is the pathological process by which nerve cells are damaged or killed by excessive stimulation by glutamate. Although neuron degeneration and death are the ultimate consequences of multiple sclerosis (MS), it is now widely accepted that alterations in the function of surrounding glial cells are key features in the progression of the disease. The present knowledge raise the possibility that the modulation of glutamate release and transport, as well as receptors blockade or glutamate metabolism modulation, might be relevant targets for the development of future therapeutic interventions in MS.

Deleterious versus protective autoimmunity in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disorder of central nervous system, in which myelin specific CD4(+) T cells have a central role in orchestrating pathological events involved in disease pathogenesis. There is compelling evidence that Th1, Th9 and Th17 cells, separately or in cooperation, could mediate deleterious autoimmune response in MS. However, the phenotype differences between Th cell subpopulations initially employed in MS pathogenesis are mainly reflected in the different patterns of inflammation introduction, which results in the development of characteristic pathological features (blood-brain barrier disruption, demyelination and neurodegeneration), clinically presented with MS symptoms. Although, autoimmunity was traditionally seen as deleterious, some studies indicated that autoimmunity mediated by Th2 cells and T regulatory cells could be protective by nature. The concept of protective autoimmunity in MS pathogenesis is still poorly understood, but could be of great importance in better understanding of MS immunology and therefore, creating better therapeutic strategies.

Synthesis of mesoporous triple-metal nanosorbent from layered double hydroxide as an efficient new sorbent for removal of dye from water and wastewater

In this study, co-precipitation synthesis of the mesoporous triple-metal nanosorbent from Fe, Cu, Ni layered double hydroxide (FeCuNi-LDH), on the basis of the data obtained from the TG analysis was carried out. The FTIR spectroscopy and XRD results confirm the formation of CuO, NiO and Fe2O3 nanoparticles, while the EDX analysis does not show significant variations on the surface in elemental composition. BET analysis shows that FeCuNi-280 (FeCuNi-LDH calcinated at 280 °C) with mesoporous structure, has larger surface area compared to FeCuNi-LDH and FeCuNi-550 (FeCuNi-LDH calcinated at 550 °C). The value of pHPZC of FeCuNi-280 is found to be 8.66. Obtained FeCuNi-280 material showed the ability for efficient removal of dye Reactive Blue 19 (RB19) from water, with a very high sorption capacity of 480.79 mg/g at optimal conditions: the sorbent dose of 0.6 g/dm3, stirring speed of 280 rpm and pH 2. The kinetics results of the sorption process were well fitted by pseudo-second order and Chrastil model, and the sorption isotherm was well described by Sips, Langmuir and Brouers-Sotolongo model. FeCuNi-280 was easily regenerated with aqueous solution of NaOH, and reutilization was successfully done in five sorption cycles. The present study show that easy-to-prepare, relatively inexpensive nanosorbent FeCuNi-280 is among the best sorbents for the removal of RB19 dye from water solution and wastewater from textile industry in wide range of pH.

IL-17 signalling in astrocytes promotes glutamate excitotoxicity: Indications for the link between inflammatory and neurodegenerative events in multiple sclerosis

OBJECTIVE Th-17 cells have been exclusively referred to inflammatory events in multiple sclerosis (MS), while their importance in the development of glutamate excitotoxicity and the consequent neurodegeneration has been a completely unexplored concept. Accordingly, the objective of our study was to assess IL-17A effect on astrocyte ability to metabolize and release glutamate, considering that astrocytes had the central role in glutamate homeostasis. METHODS By using primary rat astrocyte cultures, astrocyte ability to uptake glutamate was estimated by the alterations of glutamate transporters (GLAST and GLT-1) expression, whereas changes in glutamine synthetase expression were used to estimate the ability to metabolize glutamate. Gene expression was determined by real time polymerase chain reaction (rtPCR). IL-17A effect on astrocyte ability to produce glutamate was investigated directly, by measuring the level of released glutamate using high performance liquid chromatography (HPLC). RESULTS Lower concentrations of IL-17A reduced the expressions of both glutamate transporters and glutamine synthetase; however, this effect was lost when IL-17A was applied in a higher dose. IL-17A did not significantly modify glutamate release from astrocyte in basal conditions, but following Ca2+ stimulation, as well as Ca2+ removal from the culture medium, IL-17A stimulated glutamate release in dose-dependent manner. CONCLUSION Together, these results support that IL-17A could promote glutamate excitotoxicity by decreasing astrocyte ability to uptake and convert glutamate to non-toxic glutamine, but also by stimulating Ca2+ dependent glutamate release. Such interactions between IL-17A and glutamate excitotoxicity implicate the potential link between inflammation and neurodegeneration during MS pathogenesis, and identify astrocytes as a potential target in achieving neuroprotective effects in MS.

Efficient simulation of thin anisotropic conductive materials by using digital filter-based TLM method

In this paper, a digital filter technique is used for an efficient modelling of thin anisotropic conductive materials. Appropriate digital filter is developed to incorporate the scattering parameters of an anisotropic conductive panel allowing to include its presence without the need to model the panel thickness. The filter is implemented in the Z-TLM method. The example of carbon fibre composite material with frequency independent anisotropic electric conductivity is used to verify the accuracy and efficiency of the presented approach.

Granulocyte-macrophage colony-stimulating factor as a mediator of autoimmunity in multiple sclerosis

Autoreactive, myelin-specific, CD4+ T cells have a central role in multiple sclerosis (MS) pathogenesis; however the exact phenotype characteristics of these cells remain elusive. Recently, granulocyte-macrophage colony-stimulating factor (GM-CSF) expression has emerged as the main pathological signature of the encephalogenicity in both T and B cell compartment. In this review we have summarized the current data supporting GM-CSF relevance in MS pathophysiology, in the context of both immunomodulatory and neuroinflammatory processes; as well as the potential cellular sources of this stimulating factor, including different T and B cell subsets.

Immunohistochemical and karyometric similarities and differences of salivary gland tumors between pleomorphic adenoma, basal cell adenoma and polymorphous low grade adenocarcinoma

Uvod: Tumori pljuvačnih žlezda su veoma retke neoplazme. S obzirom na njihovu patohistološku sliku, ovi tumori predstavljaju veoma veliki dijagnostički izazov. Cilj: istaživanja je diferencijacija ova tri tipa tumora primenom imunohistohemijske i morfometrijske analize, kao i određivanje visine Ki67 proliferativnog indeksa. Materijal i metode: Istraživanje je obuhvatilo 44 tumora, 20 pleomorfnih adenoma, 12 adenoma bazalnih ćelija i 12 polimorfnih adenokarcinoma niskog gradusa. Analizirana je ekspresija Ki67, p53 i HER-2 antigena, kao markera proliferacije. U sklopu diferencijalne dijagnostike, analizirana je ekspresija CEA, EMA, GFAP, p63, vimentina, CK14, α-SMA, S-100 protein i WT1 antigena. Morfometrijska analiza vršena je u softverskom paketu „ImageJ” verzija 1.43u. Rezultati: Neoplastične ćelije u pleomorfnom adenomu su pokazale jaku ekspresiju GFAP, p63, WT1, vimentin i S100. U grupi od dvanaest polimorfnih adenokarcinoma niskog gradusa prisutna je difuzna ekspresija CK14, S100, vimentin i EMA su bili apsolutno eksprimirani, dok je αSMA bio negativan. Adenom bazalnih ćelija pokazuje pozitivnost na S-100, CEA, p63 i vimentin. Analizom vrednosti proliferativnog Ki67 indeksa ustanovljena je statistički značajna razlika u grupi pleomorfnog adenoma, što se dovodi u vezu sa čestim recidiviranjem. Morfometrijskom analizom se uočavaju veće vrednosti u grupi polimorfnog adenokarcinoma niskog gradusa, ali su statistički značajne razlike nađene samo za Feretov dijametar i integrisanu optičku gustinu u odnosu na pleomorfni adenom (p<0,05). U grupi adenoma bazalnih ćelija tumorske ćelije su pokazale statistički veće vrednosti za integrisanu optičku gustinu u odnosu na pleomorfni adenom (p<0,001). Zaključak: Za diferencijalnu dijagnozu tumora pljuvačnih žlezda, pored osnovne mikromorfološke, neophodna je i imunohistohemijska i morfometrijska analiza.

Tumor-Infiltrating Lymphocytes and Breast Cancer: Are Immune Checkpoint Inhibitors Ready for Prime Time in Breast Cancer?

Summary In recent years, results obtained from different studies with large cohorts have revealed a bond between the presence of extensive lymphocytic infiltration and favourable prognostic associations in the early-stage of breast cancer (BC) and high response rates to neoadjuvant chemotherapy. Examiners used tumors from large cohorts of patients who took part in randomized neoadjuvant and adjuvant clinical trials. The importance of tumor infiltrating lymphocytes (TILs) appears to be subtype-specific and varies depending on the histological characteristics of the tumor. TILs have proven to be a good prognostic marker, but only in highly proliferative breast tumors such as triple negative breast tumors (TNBC) or HER 2 positive BC. In the era when standard, well-known, prognostic and predictive biomarkers are ever changing and the use of molecular profiling analyses are increasing, we are looking for techniques to improve our understanding of tumor biology and improve patient outcome. The relevance of TILs cannot be ignored but needs to be properly evaluated in larger prospective studies which must encompass the parameters set out in previous studies. The use of TILs as prognostic biomarkers in early breast cancer may represent a new dawn, and use of immunotherapy, especially immune checkpoint inhibitors, probably is the future for the breast cancer but it is not yet ready for prime time.