Aysel Pekel

The bisphosphonate zoledronic acid induces cytotoxicity in human myeloma cell lines with enhancing effects of dexamethasone and thalidomide.

Bisphosphonates have recently been introduced in the therapeutic armamentarium for long-term treatment of patients with multiple myeloma. These pyrophosphate analogs not only reduce the occurrence of skeletal events but also provide clinical benefit to patients and improve the survival of some of them. The existence of these capabilities raises the possibility that these compounds may have a direct antiproliferative effect on tumor cells. To investigate whether these drugs exert a direct antitumor effect, we exposed human myeloma cell lines ARH-77 and RPMI-8226 to increasing concentrations of zoledronic acid (ZOL) in vitro. A concentration- but not time-dependent cytotoxic effect was detected with drug treatment of ARH-77 and RPMI-8226 cell lines (30% and 60% at 48 hours and 38% and 62% at 72 hours, respectively, for 50µM of ZOL). Cytotoxicity was not due to ZOL-induced chelation of extracellular calcium as shown by control experiments with the calcium chelator ethylene glycol-bis(β-aminoethylether)-N,N,N’,N’-tetraacetic acid. Addition of the competitive inhibitor of the nitric oxide synthase Nω-nitro-L-arginine methyl ester did not modulate ZOL-induced cytotoxicity. However, a decrease in the number of apoptotic cells was detected when protein kinase C was inhibited by addition of staurosporine to ZOL-containing cultures. Cytotoxicity also was increased by addition of dexamethasone (Dex) and thalidomide (Thal) to ARH-77 and RPMI-8226 cultures. We demonstrated that exposing myeloma cell lines ARH-77 and RPMI-8226 to ZOL inhibits cell growth in a dose-dependent but not a time-dependent manner and that combination of Dex and Thal with ZOL induces apoptotic cell death, providing a rationale for potential applications in vivo.

Serum interleukin-18 levels in patients with Behçet’s disease. Is its expression associated with disease activity or clinical presentations?

Interleukin (IL)-18 is a proinflammatory cytokine which plays a crucial role in T helper (Th)1 type immune response. The aim of this study is to investigate the relationship of serum levels of IL-18 with disease activity and clinical presentations in patients with Behcet’s disease (BD). Sixty patients with BD and 20 healthy controls were included in the study. Patients were grouped as having active or inactive disease according to the Leeds activity score. They were also separated as a systemic involvement or mucocutaneous symptoms only. Patients with systemic involvement were further grouped according to the presence of ocular, articular and vascular involvement. IL-18 levels were significantly higher in all patient subgroups as compared to healthy controls and found to be correlated with the activity score in patients having active disease. In conclusion, this cytokine participates in the pathogenesis of BD and its levels are correlated with the disease activity. Detection of increased levels of IL-18 in patients with inactive disease implies that Th1 activation and subclinical inflammation persist during the inactive period of the disease.

Synovial proinflammatory cytokines and their correlation with matrix metalloproteinase-3 expression in Behçet’s disease. Does interleukin-1β play a major role in Behçet’s synovitis?

The objective of this study has been the well established fact that proinflammatory cytokines and metalloproteinases play a crucial role in the pathogenesis of chronic arthritis as well as the development of pannus, with the eventual erosive changes. Among the proinflammatory cytokines, interleukin-18 (IL-18) has been shown to contribute to the pathogenesis of chronic synovitis by increasing the secretion of interleukin-1beta (IL-1β) and the tumor necrosis factor-alpha (TNF-α) and also stimulating angiogenesis. The aim of this study is to investigate the synovial IL-18, IL-1β, TNF-α and matrix metalloproteinase-3 (MMP-3) levels in patients with Behçet’s disease (BD), and compare them with the levels of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). 30 patients with BD, 20 with RA, and 20 with OA were included in the study. The synovial levels of IL-18, IL-1β, TNF-α and MMP-3 were detected using the two-step sandwich ELISA method. The synovial IL-18, TNF-α and MMP-3 levels were significantly higher in RA patients than patients with BD (P=0.004, 0.019, 0.025, respectively) and with OA (P=0.004, 0.045, 0.032, respectively). There were no differences, with respect to the cytokine levels, when patients with BD were compared with those with OA. Patients with RA and BD had higher IL-1β levels than patients with OA (P=0.017, 0.013, respectively). However, no such difference was found for IL-1β between BD and RA patients. Among patients with RA, positive correlations were found between TNF-α and MMP-3 (r=0.683, P=0.001). Our results showed that MMP-3 and proinflammatory cytokines, except IL-1β, were expressed in relatively small quantities in Behçet’s synovitis. Detection of the lower levels of these cytokines and metalloproteinases might explain the non-erosive character of Behçet’s arthritis. We suggest that IL-1β may be involved in the pathogenesis of Behçet’s synovitis.

Diagnostic Utility of Anti-Cyclic Citrullinated Peptide and Anti-Modified Citrullinated Vimentin Antibodies in Rheumatoid Arthritis

Several autoantibodies found in RA are directed to epitopes in citrullinated proteins. One of them is anti modified citrullinated vimentin (Anti-MCV). We tested the value a newly developed ELISA for the detection of antibodies against a genetically modified citrullinated vimentin (anti-MCV) in comparison with an anti-CCP based ELISA system for the diagnosis of RA. Thirty-five patients with RA (mean age; 42.6 +/- 10.87 years, mean disease duration; 9.37 +/- 3.98 years) were enrolled in this study. Twenty -five ankylosing spondylitis (mean age; 35.88 +/- 6.64 years, mean disease duration; 10.25 +/- 4.61 years), and 19 healthy subjects (mean age; 40.26 +/- 5.11 years) served as controls. Anti-CCP antibodies and Anti-MCV antibodies were measured using ELISA. In all RA patients, mean anti- CCP level was 69.07 +/- 90.43 U/ml and anti-MCV level was 665.77 +/- 1040.19 U/ml. In patients with AS, the mean anti-CCP level was 10.7 +/- 5.22 U/ml and anti-MCV level was 40.54 +/- 20.15 U/ml. In healthy controls, the mean anti-CCP level was 11.11 +/- 7.65 U/ml, anti-MCV level was 23.12 +/- 12.04 U/ml. In patients with active RA, the mean serum anti-CCP level was 100.54 +/- 98.07 U/ml and anti-MCV level was 998.74 +/- 1154.93 U/ml. In patients with inactive RA, the mean serum anti-CCP level was 8.77 +/- 1.55 U/ml and anti-MCV level was 27.59 +/- 23.10 U/ml. According to these results; In patients with RA, the mean serum anti-MCV and anti-CCP levels were significantly high compared to patients with AS and healthy controls (p=0.002, p=0.001, p=0.002, p=0.001 respectively). The mean serum anti-MCV and anti- CCP levels were significantly higher in active patients with RA than in inactive patients with RA patients (p=0.001 and p=0.001 respectively). In inactive patients with RA, the mean serum anti-MCV and anti-CCP levels were similar in patients with AS and patients (p=0.484, p=0.308, p=0.09 and p=0.222 respectively). The mean serum anti-MCV levels were correlated with DAS 28 (r=0.531, p=0.001), VAS score (r=0.332, p=0.01), ESR (r=0.458, p=0.001), serum CRP levels (r=0.568, p=0.01), serum RF levels (r=0.529, p=0.001), swollen joints number (r=0.525, p=0.001) and tender joints number (r=0.638, p=0.001). As a result; measurement of serum anti-MCV levels is useful for diagnosis of RA and combined use of anti-MCV and RF may be more useful prognostic factor than either method alone, RF and anti-CCP.

Tissue levels of adiponectin, tumour necrosis factor-alpha, soluble intercellular adhesion molecule-1 and heart-type fatty acid-binding protein in human coronary atherosclerotic plaques

Background  There is little information available about any link between the levels of adiponectin, intercellular adhesion molecule‐1 (ICAM‐1), tumour necrosis factor‐α (TNF‐α) and heart‐type fatty acid‐binding protein (H‐FABP) in coronary atherosclerotic plaque specimens.

Different ELR (+) angiogenic CXC chemokine profiles in synovial fluid of patients with Behçet’s disease, familial Mediterranean fever, rheumatoid arthritis, and osteoarthritis

The aim of the present study was to determine synovial levels of ELR (+) CXC chemokines, known to attract mainly neutrophils to inflamed tissues by binding the neutrophil chemokine receptors CXCR1 and CXCR2 and promoting neovascularization in patients with various inflammatory disorders. The study group consisted of 14 patients with Behçet’s disease and nine with familial Mediterranean fever. Fourteen patients with rheumatoid arthritis and 16 with osteoarthritis served as controls. Synovial chemokine levels were measured by two-step sandwich enzyme-linked immunosorbent assay, and significant differences were found in the various chemokines studied. In addition to its angiogenic properties, increased synovial levels of interleukin-8 by attraction of more neutrophils to synovial fluids might also be responsible for the acute synovitis in patients with Behçet’s disease. However, the absence of chronic changes with the eventual development of pannus and erosions might result from relatively lower expression of interleukin-8 and the transient, short-lived nature of the arthritis observed in these patients.

Platelet-derived microparticle levels in women with recurrent spontaneous abortion

To investigate the significance of platelet‐derived microparticles (PMPs) in women with recurrent spontaneous abortion.

Effect of zinc and melatonin supplementation on cellular immunity in rats with toxoplasmosis

The effects of zinc (Zn) and/or melatonin supplementation on cellular immunity were investigated in rats infested with Toxoplasma gondii. Fifty Sprague-Dawley male rats were used for this study. All animals were fed a normal diet, ad libitum, containing 97 mg Zn/kg. They were divided into five experimental groups, as follows. Group I (n=10) received intraperitoneal injections of zinc sulfate at a dose of 3 mg/kg/d for 3 wk. Group II (n=10) received intraperitoneal injections of melatonin at a dose of 3 mg/kg/d for 3 wk. Group III (n=10) received intraperitoneal injections of zinc sulfate (3 mg/kg/d) and melatonin (3 mg/kg/d) for 3 wk. Group IV (n=10) was infested controls. Group V (n=10) was healthy controls. There were no differences in the percentage of CD3+ lymphocytes among all groups. For groups I–III, the CD4+ and CD8+ ratios were higher than those of the groups IV and V controls (p<0.01). Similarly, the total lymphocyte ratios in groups I–III were higher than those of infested and healthy controls (p<0.01). The total lymphocyte ratios in group III were significantly higher than those of groups I and II (p<0.01). The plasma Zn levels in the supplemented groups were significantly higher than those of control groups IV and V (p<0.01). These results suggest that melatonin and/or Zn supplementation may activate cellular immunity by stimulating CD4+ and CD8+ production in infected rats with T. gondii.

Proteasome inhibitor bortezomib increases radiation sensitivity in androgen independent human prostate cancer cells.

OBJECTIVES To investigate the effects of a strong proteasome inhibitor, bortezomib alone or in combination with radiotherapy on androgen-independent DU145 human prostate cancer cells. Proteasomes play important roles in cell cycle, proliferation, apoptosis, angiogenesis, and cellular resistance to chemotherapy and radiotherapy. METHODS Increasing concentrations of bortezomib alone or in combination with radiation were applied to DU145 cells and IC(50) values that inhibited cell growth by 50% were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium-bromide assay. Apoptosis was determined using annexin V staining by flow cytometry. mRNA levels of proapoptotic caspase-3 and antiapoptotic Bcl-2 genes were examined by reverse transcriptase polymerase chain reaction. RESULTS The IC(50) value of bortezomib was found to be 28 microm although 400- and 800-cGy radiation decreased the cell proliferation by 14% and 28%, respectively. In 400- and 800-cGy radiation applied DU145 cells, IC(50) value of bortezomib decreased to 23- and 12 microm, respectively. Exposure to 5 microm bortezomib for 48 hours caused apoptosis in 35% of the population whereas 800-cGy radiation resulted apoptosis in 14% of cells. However, 42% of DU145 cells that were exposed to 800 cGy and 5 microm bortezomib underwent apoptosis. Reverse transcriptase polymerase chain reaction results showed a significant decrease in mRNA levels of antiapoptotic Bcl-2 gene and an increase in proapoptotic caspase-3 gene expression in the combination group compared to control group. CONCLUSIONS Bortezomib increases radiation sensitivity in androgen-independent human DU145 prostate cancer cells through inhibition of Bcl-2 and induction of caspase-3 genes.

Effects of zinc deficiency and pinealectomy on cellular immunity in rats infected with Toxoplasma gondii

The effects of zinc and/or melatonin deficiencies on cellular immunity were investigated in rats infected with Toxoplasma gondii. A total of 50 adult male Sprague-Dawley rats were divided into 5 groups of 10 rats each. In group I, the rats were infected with T. gondii and fed a zinc-deficient diet; in group II, the rats were infected and their pineal gland was surgically removed. Group III included rats that were infected, pinealectomized, and fed a zinc-deficient diet. Group IV consisted of T. gondii-infested rats that received no treatment of any kind, and group V were normal controls. After 3 wk of treatment, all rats were sacrificed and the percentages of CD3, CD4, and CD8 lymphocytes, zinc, and melatonin levels in plasma and the percentage of lymphocyte in blood smears were analyzed. The CD3 ratios of groups I–III were significantly lower than those of groups IV and V (p<0.01). The CD4 lymphocytes were significantly higher in group IV than that in all other groups (p<0.05). In group IV, the CD8 lymphocytes were higher than in groups I–III (p<0.01) and those in group V were higher than for groups I and III (p<0.01). Lymphocyte incidence in group IV was higher than in the other four groups (p<0.01). The plasma zinc and plasma melatonin levels in groups I–III were significantly lower than those in the controls (p<0.01, both cases). These results suggest that zinc and/or melatonin deficiency have a negative influence on cellular immunity in rats with toxoplasmosis.