Elżbieta Iłendo

Levetiracetam protects hippocampal neurons in culture against hypoxia-induced injury

Many experimental studies indicate that some antiepileptic drugs possess neuroprotective properties in varied models of neuronal injury. Levetiracetam is a second-generation antiepileptic drug with a novel mechanism of action. In the present study, we evaluated the putative neuroprotective effect of levetiracetam on primary hippocampal cultures at seven day in vitro. Cell death was induced by incubation of neural cultures in hypoxic conditions over 24 hours. Neuronal injury was assessed by morphometric investigation of death/total ratio of neurons in light microscopy using Trypan blue staining and by evaluation of lactate dehydrogenase (LDH) release in the culture medium. Our results indicate that pre-conditioning of hippocampal cultures with high concentrations of levetiracetam (100 μM and 300 μM) protects neurons against hypoxia-induced death. Two-fold higher number of neurons remained viable as compared to control cultures without drug. Lack of neuroprotective action of the drug on hippocampal neural cultures was observed, when a low concentration (10 μM) of levetiracetam was used.

Study of the protective effect of calcium channel blockers against neuronal damage induced by glutamate in cultured hippocampal neurons

BACKGROUND The aim of this study was to examine the putative protective effect of calcium channel blockers on hippocampal neurons in the experimental model of excitotoxic damage. METHODS Seven-day old primary dissociated cultures of rat hippocampal neural cells containing one of the following calcium channel blockers: cinnarizine, flunarizine or nimodipine were exposed to glutamate-induced injury. Quantitative assessments of neuronal injury were accomplished by measuring lactate dehydrogenase (LDH) activity in the media 24 h after exposure to glutamate and by counting and establishing the apoptotic and necrotic cells in flow cytometry with Annexin V-FITC/PI staining. RESULTS In our experiment, glutamate induced a 339% elevation of apoptotic cells and a 289% increase of necrotic cells in hippocampal neurons as compared to control cultures without drugs. In cultures containing flunarizine, glutamate-induced cell apoptosis was suppressed by 62% while necrosis showed no significant alternation. Cinnarizine exerted no anti-apoptotic effects on glutamate-injured cultured hippocampal neurons, while nimodipine intensified the apoptotic pathway of cell death and promoted an increase in the number of apoptotic neurons by 26%. When cinnarizine or nimodipine were used, the percentage of necrotic cells was significantly lower when compared with glutamate-injured cultures and it amounted to 44% and 24% for cinnarizine and nimodipine, respectively. CONCLUSIONS The obtained results suggest the beneficial anti-apoptotic potential of flunarizine and the anti-necrotic potential of cinnarizine against glutamate-induced death of cultured hippocampal neurons. Nimodipine can protect neurons against necrosis, but has an intensified adverse pro-apoptotic effect on cultured neurons in the experimental model of excitotoxic injury.

Profile of Exoglycosidases in Synovial Cell Cultures Derived from Human Synovial Membrane

Objective Determining the activity of lysosomal exoglycosidases in tissue cultures of synoviocytes derived from the knee joints of patients with injured anterior cruciate ligaments (ACL), juvenile idiopathic arthritis (JIA), and rheumatoid arthritis (RA). Methods The following exoglycosidases in cultured synoviocytes were analyzed with p-nitrophenyl derivatives of appropriate sugars as substrates: hexosaminidase (HEX) and its isoenzyme A (HEX-A), β-glucuronidase (GluA), β-galactosidase (GAL), α-mannosidase (MAN), and α-fucosidase (FUC). Results In our cell cultures, fibroblast-like synovial cells (FLS) dominated. In the group of patients with ACL-injuries, and in the groups of patients with JIA and RA, the activity of the investigated exoglycosidases was significantly higher in the intra- rather than in the extracellular compartment. Hexosaminidase was the predominant exoglycosidase. Stimulation of synoviocytes by IL-1β in cell cultures significantly increased the activity of HEX, HEX-A, and GluA in both compartments, as well as of GAL, MAN, and FUC in the intracellular compartment. Stimulation by IL-1β rheumatoidal synoviocytes increased by 128–201% the activity of HEX and HEX A in intracellular compartments and 33–72% in extracellular compartment. Conclusions The profile of lysosomal exoglycosidases in a cell culture of human synoviocytes is similar, but not identical, to those in the knee joint. Hexosaminidase is the dominant glycosidase in cultured unstimulated and IL-1β-stimulated human synoviocytes. The HEX inhibitors may be new drugs for the treatment of inflamed knee joints.

Generation of Functional T-Regulatory Cells in Children with Metabolic Syndrome

Recent research implies a role of decreased number and/or function of T-regulatory cells (Tregs) in low-grade inflammation associated with obesity and atherosclerosis. The enhancement of atheroprotective immunity by the expansion of Tregs could serve as a therapeutic strategy in obesity-related immunological disturbances. The aim of our study was an attempt to generate Treg cells in children with risk factors for the development of cardiovascular disease and to compare the results to those obtained in healthy subjects. The study group consisted of 30 children with metabolic syndrome (MS) and 30 controls. Conventional CD4+CD25− cells separated from the peripheral blood were converted into Treg cells with the use of CD3/CD28 antibodies and interleukin (IL)-2/transforming growth factor (TGF)-β stimulation. The expression of critical Treg molecules and cytokines was assessed at mRNA and protein levels. The percentages of Treg cells in the peripheral blood were significantly lower in the children with MS compared to the healthy subjects. After the culture with CD3/CD28 and IL-2/TGF-β we detected a significant increase in the expression of Tregs marker transcription factor FoxP3. The Tregs induced from the children with MS varied from the ones obtained in the controls in the expression of some molecules at mRNA level (e.g. IL-27, LGAL, KLF10 and NRP1) yet not in proliferation studies. For the first time, we have demonstrated the possibility of generating functional Treg cells in children with MS. The results of our study could be used in the design of therapeutic interventions in obesity associated immunologic disturbances.

Upregulation of antigen-processing machinery components at mRNA level in acute lymphoblastic leukemia cells after CD40 stimulation

The development of immunotherapy in hematologic malignancies has been observed in the last few years. One of the approaches is the use of cancer vaccines based on leukemia-derived dendritic cells (DC). Recent studies from our laboratory and other laboratories have shown that CD40 stimulation improves leukemia cells immunogenicity and generates an antitumor immune response. The design of future cancer vaccines requires the knowledge concerning the function of dendritic cells including antigen processing. The aim of our present study was the assessment of antigen-processing machinery (APM) components in acute lymphoblastic leukemia (ALL) cells before and after CD40 stimulation at messenger RNA (mRNA) level. Twenty-five children with ALL were enrolled into the study. Leukemic cells were stimulated (or not) with CD40L and IL-4. Elements of the antigen-processing machinery (MB1, LMP2, LMP7, LMP10, TAP1, TAP2, calnexin, calreticulin, tapasin, ERp57, zeta, delta) were determined by real-time PCR technique. The expression of important costimulatory and adhesion molecules considered as DC markers (CD40, CD54, CD80, CD83, CD86) were determined at the mRNA (PCR) and protein (flow cytometry) levels. The following are the results of our study: (1) We noted an upregulation of all costimulatory and adhesion molecules at the mRNA and protein levels in ALL cells after the culture; (2) the significant rise in expression of nearly all APM components after CD40 stimulation was observed. This confirms specific stimulation of the antigen-processing system in ALL cells by CD40L. Future work should focus on the clinical significance of these findings for immunotherapy in leukemias.

The mRNA expression of pro- and anti-inflammatory cytokines in T regulatory cells in children with type 1 diabetes

Type 1 diabetes mellitus (T1DM) is caused by the autoimmune-mediated destruction of insulin-producing beta cells in the pancreas. T regulatory cells (Tregs) represent an active mechanism of suppressing autoreactive T cells that escape central tolerance. The aim of our study was to test the hypothesis that T regulatory cells express pro- and anti-inflammatory cytokines, elements of cytotoxicity and OX40/4-1BB molecules. The examined group consisted of 50 children with T1DM. Fifty two healthy individuals (control group) were enrolled into the study. A flow cytometric analysis of T-cell subpopulations was performed using the following markers: anti-CD3, anti-CD4, anti-CD25, anti-CD127, anti-CD134 and anti-CD137. Concurrently with the flow cytometric assessment of Tregs we separated CD4+CD25+CD127dim/- cells for further mRNA analysis. mRNA levels for transcription factor FoxP3, pro- and anti-inflammatory cytokines (interferon gamma, interleukin-2, interleukin-4, interleukin-10, transforming growth factor beta1 and tumor necrosis factor alpha), activatory molecules (OX40, 4-1BB) and elements of cytotoxicity (granzyme B, perforin 1) were determined by real-time PCR technique. We found no alterations in the frequency of CD4+CD25highCD127low cells between diabetic and control children. Treg cells expressed mRNA for pro- and anti-inflammatory cytokines. Lower OX40 and higher 4-1BB mRNA but not protein levels in Treg cells in diabetic patients compared to the healthy children were noted. Our observations confirm the presence of mRNA for pro- and anti-inflammatory cytokines in CD4+CD25+CD127dim/- cells in the peripheral blood of children with T1DM. Further studies with the goal of developing new strategies to potentiate Treg function in autoimmune diseases are warranted.

Disturbances in some Gene Expression in T Regulatory Cells Separated from Children with Metabolic Syndrome

The metabolic syndrome (MS) is defined as a cluster of risk factors, including abdominal obesity, dyslipidaemia, glucose intolerance and hypertension, which increase the risk for coronary heart disease. The immunological aspects of obesity and MS, including the role of T regulatory cells, have been intensively investigated. The aim of this study was to determine whether there is any disturbance in T regulatory cells number and/or function in children with MS. The percentages of T regulatory cells in the peripheral blood of children fulfilling the International Diabetes Federation criteria of the disease (n = 47) were assessed. Treg cells were also separated for further analysis of multiple genes important in their function with the use of real‐time RT‐PCR. We did not observe any difference in Treg percentages between study and control group but there was lower expression of some molecules including transforming growth factor‐β and interleukin‐12 family members in Treg cells separated from children with MS compared to the healthy subjects. Our study is the first to report significant disturbances in some gene expression in T regulatory cells separated from children with MS. The results should be useful for further research in this field, including immunotherapeutic interventions.

Production of cytokines by mononuclear cells of hypertrophic adenoids in children with otitis media with effusion

Hypertrophic adenoids with otitis media with effusion is a common infectious disease and present a serious otological problem in children. Cytokines, potent inflammatory mediators, play important role in the initiation of immunological response in otitis media. Adenoids excised due to hypertrophy with or without chronic otitis media with effusion were used to isolate mononuclear cells. Secretion of cytokines by non-stimulated and PHA-stimulated cells was determined by specific ELISAs. We found a significant increase in the production of IL-5 and TNF-a secreted by adenoidal cells of children with otitis media with effusion compared to group with hypertrophic adenoids. No differences were found in the secretion of IL-8, IL-6, and IL-10 between these two groups of patients. Our results suggest a difference between the immunological responses in the course of hypertrophic adenoids with otitis media as compared to hypertrophic adenoids.

Generation of T regulatory cells in children with newly diagnosed type 1 diabetes mellitus.

UNLABELLED There is increasing evidence that T-regulatory (Treg) cells could be used to prevent or cure autoimmune diseases including type 1 diabetes mellitus (T1DM). The aim of the present study was to verify the hypothesis that functional Treg cells can be generated from conventional T-cells separated from a small amount of peripheral blood of children with newly diagnosed T1DM (N=25). METHODS CD4(+)CD25(-) cells were cultured with Treg expander (CD3/CD28) and IL-2 for generating de novo Treg cells. The assessment of the expression of selected genes and proteins critical to Treg function and the proliferation assays were performed with the use of real-time RT-PCR and flow cytometry. RESULTS After a 4-week stimulation with Treg expander and IL-2, the percentage of T-regulatory cells was significantly higher compared to the cells treated with medium alone (with no difference between diabetic and control children). However, we found some disturbances in the gene expression at mRNA level for molecules crucial for T-reg function. The induced Tregs from diabetic and control children were fully functional as assessed in proliferation assays. IN SUMMARY Despite some disturbances at mRNA level in the critical gene expression, the suppressive properties of induced Treg cells from diabetic and control children were effective.

Acute lymphoblastic leukaemia cells express CCR7 but not higher amounts of IL-10 after CD40 ligation.

Objective. Production of cytokines that support T‐cell activation and proliferation and migration to lymph nodes is one of the most important terms of cancer vaccine development. In previous studies we and others used CD40 ligation to obtain higher expression of co‐stimulatory and adhesion molecules on leukaemic cells from children with acute lymphoblastic leukaemia (ALL). This time we assess the cytokine and chemokine gene expression profile in CD40‐stimulated ALL cells. Material and methods. Malignant cells from 25 children with BCP‐ALL were stimulated (or not) with huCD40LT and rIL‐4 for 96 h. Eleven different molecule, cytokine and chemokine mRNAs levels (CCR7, IL‐23, TGF‐β‐IP, IFN‐γ, IL‐10, CD1a, CD40, CD54, CD80, CD83, CD86) were determined using the real‐time PCR technique with TaqMan chemistry using ready‐to‐use low‐density arrays for gene expression by Applied Biosystems. Results. 1) Increases in mRNA levels for CD40, CD54 and CD80 after CD40L and IL‐4 stimulation were observed, 2) CCR7 mRNA expression was higher after CD40 ligation than before the culture (p = 0.002), 3) IL‐10 mRNA expression was higher after the culture with medium than before the culture (p = 0.01). Conclusions. The results show that leukaemia‐derived dendritic cells obtained with CD40 ligation express CCR7 – chemokine is involved in migration to lymph nodes and does not produce higher amounts of IL‐10, a potent immunosuppressive cytokine. Our preclinical findings could be used in the design of immunotherapy trials for the treatment of children with ALL.