The effects of ozone application on genotoxic damage and wound healing in bisphosphonate-applied human gingival fibroblast cells.

OBJECTIVES: Medication-related osteonecrosis of the jaws (MRONJ) is an extremely therapy-resistant disease involving the jaws especially following bisphosphonate treatment. Bisphosphonates accumulate in bone in concentrations sufficient to be directly toxic to the oral epithelium. Current therapeutic options are inadequate for the prevention and treatment of MRONJ. The aim of this study was to investigate effects of ozone gas plasma therapy on wound healing in bisphosphonate-applied human fibroblasts. MATERIAL AND METHODS: Human primary gingival fibroblasts were cultured. Cytotoxic concentrations (IC50) of bisphosphonates (pamidronate (PAM), alendronate (ALN), and zoledronate (ZOL)) were determined by MTT test. A 60 µg/µl for 30 s of ozone gas plasma application was performed to all experimental culture flasks after drug treatment at 24-h intervals as 3 s/cm2. Genotoxic damages were evaluated by comet assay and wound healing was determined by in vitro scratch assay. RESULTS: PAM, ALN, and ZOL applications caused genotoxic damage on primary human gingival fibroblast DNA. Ozone gas plasma therapy significantly decreased the genotoxic damage (p < 0.05), and this application provided 25, 29, and 27% less genotoxic damage in order of ALN, PAM, and ZOL groups. Ozone gas plasma therapy significantly increased wound healing rates both in postsurgical 24th and 48th hours for all doses of experimental drug groups (p < 0.05). CONCLUSION: The ozone gas plasma application decreased genotoxic damage effect of bisphosphonate usage while improved the wound closure rate on human gingival fibroblasts. CLINICAL RELEVANCE: Ozone gas plasma therapy may be helpful in prevention of gingival healing delay in MRONJ pathogenesis especially when applied simultaneously with surgical intervention.

Effects of alendronate and pamidronate on apoptosis and cell proliferation in cultured primary human gingival fibroblasts.

Data arising from the recent literature directed the researchers to study on the degree and extent of bisphosphonate toxicity on oral mucosa in further detail. The aim of this study is to determine the half maximal inhibitory concentration of pamidronate (PAM) and alendronate (ALN) on human gingival fibroblasts in vitro using 3-[4.5-thiazol-2-yl]-2.5-diphenyltetrazolium bromide (MTT) assay and to evaluate the effects of both agents on the proliferation and apoptotic indices. Cells used in the study were generated from human gingival specimens and divided into alendronate (n = 240), PAM (n = 240), and control groups (n = 60). Based on the MTT assay results, 10(-4), 10(-5), 10(-6), and 10(-7) M concentrations of both drugs were administered and the effects were evaluated for 6, 12, 24, 48, or 72 h periods. An indirect immunofluorescence technique was used to evaluate apoptotic (anti-caspase 3) and proliferation (anti-Ki67) indices. Toxicity of both PAM and ALN was found to be the most potent at 10(-4)-10(-5) M range. The apoptotic index of PAM group was found to be significantly higher than ALN group for all concentrations especially at 24 h incubation time (p < 0.05). The decrease in the proliferation index was found similar in first 48 h for both drugs; however, after 72 h of incubation decrease in proliferation index in PAM group was found to be significantly higher (p < 0.05). Micromolar concentrations of not only PAM but also ALN rapidly affect cells generated from human oral gingival tissue by inducing apoptosis together with inhibition of proliferation. Cytotoxic effects of both ALN and PAM on primary human gingival fibroblasts, which cause significant changes in apoptotic and proliferative indices as shown in this in vitro study, suggests that the defective epithelialization of oral mucosa is possibly a major factor on the onset of bisphosphonate-related osteonecrosis of the jaw cases.

Genotoxic and cytotoxic effects of doxorubicin and silymarin on human hepatocellular carcinoma cells.

The aim of this study was to investigate genotoxic and cytotoxic effects of doxorubicin, silymarin, or in combination on HepG2 cells for 24 and 48 h. Both doxorubicin and silymarin caused dose-dependent inhibition of cell proliferation. After 48 h of treatment, doxorubicin application caused dramatically increased ratio of apoptotic cells. Both 24 and 48 h of silymarin and doxorubicin-silymarin combination caused significant increases in the rate of apoptotic cells. Applications of doxorubicin and silymarin separately for 24 h led to deoxyribonucleic acid (DNA) damages. After 48 h of incubation, doxorubicin-induced genotoxic damage was 2-fold higher than the silymarin-induced damage. After 24 and 48 h, DNA damage in response to combined applications of doxorubicin and silymarin was indifferent from silymarin- and doxorubicin-induced damage respectively. There was not any difference in genotoxicity levels between incubation periods in combined applications of doxorubicin and silymarin. Lipid peroxidation levels increased in all applications. Biopharmacotherapy with chemotherapeutic agents are of interest in the issue of adjuvant therapy. Here, we demonstrate in vitro potential genotoxic and cytotoxic antitumor effect of silymarin on HepG2 cells at achievable plasma level concentrations.

Detecting methylation patterns of p16, MGMT, DAPK and E-cadherin genes in multiple myeloma patients.

Multiple myeloma (MM) is a B-cell neoplasia characterized by the clonal proliferation of plasma cells. Besides known genetic abnormalities, epigenetic changes are also known to effect MM pathogenesis. DNA methylation is an epigenetic mechanism that silences genes by adding methyl groups to cytosine-guanine dinucleotides at the promoter regions. In this study, the methylation status of four genes; p16, O6-methyl guanine DNA methyl transferase (MGMT), death-associated protein kinase (DAPK) and E-cadherin (ECAD); at the time of diagnosis was investigated using methylation-specific polymerase chain reaction (MS-PCR). In the 20 cases studied; methylation of the promoter regions of p16, MGMT, DAPK and ECAD genes was detected in 10%, 40%, 10% and 45% of the cases, respectively. In 65% (13/20) of cases, at least one of the genes studied had promoter methylation; while 35% of cases (7/20) had methylated promoters of more than one gene. There was a significant correlation between promoter hypermethylation of MGMT and the presence of extramedullary involvement; but for the other genes no correlation was found regarding disease properties like age, disease stage, clinical course and the presence of lytic bone lesions. Determining the methylation profiles of genes in MM, could lead to a new understanding of the disease pathogenesis and guide the assessment of treatment options.

Calpain 10 gene single-nucleotide 44 polymorphism may have an influence on clinical and metabolic features in patients with polycystic ovary syndrome.

AIM: This study was designed in order to examine the relationship between Calpain 10 [single-nucleotide polymorphism (SNP) 19,43,44,63] gene polymorphisms and clinical and hormonal characteristics in women with polycystic ovary syndrome (PCOS). MATERIALS AND METHODS: One hundred and seven patients with PCOS and 114 healthy subjects were included in this study. Serum levels of sex steroids were measured for each individual. Insulin resistance (IR) was evaluated by the homeostasis model assessment (HOMA) and quantitative insulin-sensitivity check index (QUICKI) methods. Insulin and glucose responses to the oral glucose tolerance test (OGTT) were analyzed by calculating the areas under the curve for insulin (AUCI) and glucose by the trapezoidal methods.We used PCR and restriction fragment length polymorphism technique to examine Calpain 10 SNP 19, 43, 44, and 63 polymorphisms. RESULTS: Allele distribution of Calpain 10 SNP 44 gene polymorphism was observed as significantly different between the groups. Calpain 10 SNP 44 TC genotype was found to be increased in PCOS subjects (69.15%) compared to the control subjects (50%). However, when compared to control subjects, patients with PCOS had similar Calpain 10 SNP 19, Calpain 10 SNP 43, and SNP 63 gene polymorphisms. When compared with normal Calpain 10 gene SNP 44 allele in PCOS subjects, subjects with PCOS having Calpain 10 gene SNP 44 allele polymorphism had higher free testosterone, androstenedione, DHEA-S, and fasting insulin levels. Also, PCOS women with Calpain 10 gene SNP 44 allele polymorphism had high Ferriman-Gallwey (F-G) score, acne, prevalence of menstrual disturbances, waist-hip ratio, HOMA-IR, AUCI levels and low QUICKI levels. CONCLUSION: The findings show that Calpain 10 gene SNP 44 allele polymorphism may have a role in PCOS pathogenesis. However, larger-scale studies are needed in this field.

Apoptosis in raloxifene-treated postmenopausal women.

As raloxifene is a mixed estrogen receptor agonist and antagonist, it exerts different effects on apoptosis in different tissues. In this study, we aimed to evaluate apoptosis in the peripheral lymphocytes of postmenopausal women treated with raloxifene and compare it with untreated control subjects. In this way, we expected to deduce some results about the effect of raloxifene on the immune system and to serve as a guide for future studies on this newly proposed effect of a well-known agent. Twenty osteoporotic postmenopausal women treated with raloxifene for 12 months were included in this study. Another 20 osteoporotic postmenopausal women matched for age and postmenopausal years, but without any medication, were chosen as the control group. Apoptosis was evaluated using a morphological and DNA fragmentation assay, in the peripheral lymphocytes of these women. Our results revealed a decrease in the apoptosis percentages of the patients treated with raloxifene (14.6%) with respect to the control subjects (15.8%), but the difference was not statistically significant (p=0.467). This study indicated that raloxifene treatment had no apoptotic effect on peripheral human lymphocytes compared to controls.