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ABSTRACT: Data published during the last decade are suggestive of a role for mitochondrial dysfunction in the pathogenesis of schizophrenia, bipolar disorder and other psychiatric diseases. In order to determine if the mitochondrial deficits reported in the literature are caused by abnormalities in the mitochondrial DNA of psychiatric patients, we quantified mitochondrial DNA (mtDNA) levels and the 5 kb common mitochondrial deletion (CD) in postmortem frontal cortex tissue. The mitochondrial CD and mtDNA levels were measured in tissue obtained from the frontal cortex (Brodmann Area 46) of 144 individuals (45 patients with schizophrenia, 40 patients with bipolar disorder, 44 controls, and 15 patients with major depression). These variables were measured using newly developed SYBR green and TaqMan real time PCR assays. Both the TaqMan and the SYBR green assays gave similar results. There was no statistically significant difference for the quantity of the common mitochondrial deletion between controls and patients. We also did not detect a difference in the mtDNA levels amongst the diagnosis groups. There were statistically significant differences for the evaluated parameters for smokers, schizophrenic patients on antipsychotic drugs at time of death, and bipolar patients with antidepressant use and alcohol abuse. Based on this study and other reports, we conclude that neither the common mitochondrial deletion nor changes in mitochondrial DNA levels are likely to account for the mitochondrial changes associated with bipolar disorder or schizophrenia. The effect of premortem agonal factors and medication on mitochondrial dysfunction still needs further elucidation.
Acta Neurovegetativa 02/2007; 114(5):665-74. · 2.73 Impact Factor
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ABSTRACT: The purpose of this study was to investigate the potential effects of 2-methoxyestradiol, a natural mammalian steroid, in glioma cells, since antiproliferative effects of this compound had been shown earlier in several leukemia and carcinoma cell lines. The effects of 0.2, 2 and 20 microM concentrations of 2-methoxyestradiol were measured in three malignant human glioma cell lines (U87MG, U138MG, LN405) and one malignant rat glioma cell line (RG-2) using a microtiter-tetrazolium (MTT) assay. In all cell lines, a significant reduction of the viable cell number by more then 75% occurred ( P < 0.05) for concentrations of 2 and 20 microM 2-methoxyestradiol after 6 days. A concentration of 0.2 microM had smaller effects (10-40% cell reduction), which were significant in two of the cell lines tested. The apoptotic nature of cell death was further analyzed in U87MG and RG-2 cells. Caspase-3 activity was significantly induced to levels between 3.4- and 23-fold after 4 days for the two higher 2-methoxyestradiol concentrations (P < 0.05). In the cell line RG-2 nuclear fragmentation was visible in many nuclei, following stains with Hoechst H33258. A round cell morphology occurred in most treated cells, which was not accompanied by a complete destruction of the microtubule network, as it can be observed with other microtubule targeting drugs.
Journal of Neuro-Oncology 03/2005; 72(1):11-6. · 3.21 Impact Factor
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ABSTRACT: The aim of this study was a clonal analysis of gliomatosis cerebri (GC), a rare disease characterized by diffuse, extensively infiltrating glial tumors of the central nervous system. Two females of the series were not informative in assays for X-chromosomal inactivation, and a polycytosine tract of the mitochondrial DNA (mtDNA) was tested as a clonal marker. Following fluorescent PCR, a fraction of human individuals shows several electrophoretic bands in normal tissues, some of which can be lost in corresponding glial tumors. Two male patients of our series fulfilled this prerequisite and were thus informative. In patient 1, four tumor samples from the left temporal and occipital cortex, histologically corresponding to WHO grades III and IV, showed an identical loss of bands, which was not observed in tumor-free brain and in tumors from the left cerebellum, from fornix and corpus callosum, and from the right occipital cortex, corresponding to WHO grades III and IV. Since this patient exhibited a TP53 mutation in exon 7, we sequenced this exon in all tissue samples of this individual. The mutation was found selectively in the tumor samples with a loss of mtDNA bands. In patient 2, all tumors (histologically corresponding to WHO grade II) from putamen, thalamus, midbrain and right parietal cortex exhibited an identical loss of bands in the mtDNA analysis. Taken together, these results support that even distant tumors in a patient with GC can share a common clonal origin. They demonstrate the extraordinary mobility and infiltrative power of these tumor cells.
Journal of Neuro-Oncology 02/2003; 61(1):1-5. · 3.21 Impact Factor
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ABSTRACT: To identify somatic mutations in the mitochondrial DNA of glioblastomas, in a previous study the displacement loops of 17 glioblastomas and corresponding blood samples were sequenced and instabilities in repeats or transitions were detected in seven tumours. This study was extended by sequencing 10 DNA samples of diffuse astrocytomas (World Health Organisation grade II) and corresponding blood samples.
The 10 DNA samples of diffuse astrocytomas and corresponding blood samples were amplified and sequenced using fluorescent nucleotides.
No sequence differences were detected, with the exception of a quantitative shift between two genotypes heteroplasmic within the hypervariable region 2, which can be interpreted as mitotic drift. In the glioblastoma series, any particular somatic mutation was usually found in only one tumour. The only frequent alteration was coupled to a mitochondrial germline polymorphism under-represented in the low grade astrocytoma group. Moreover, a single mutation in two patients with secondary glioblastomas had already been detected in diffuse astrocytomas of these individuals.
A lower percentage of mitochondrial DNA mutations in low grade tumours cannot be deduced from these data.
Molecular Pathology 07/2002; 55(3):204-6.
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ABSTRACT: Gliomatosis cerebri (GC) is a rare tumor of the central nervous system (CNS) characterized by widespread diffuse infiltration of the brain and spinal cord by neoplastic glial cells. We report the case of a 17-year-old boy with a bioptically diagnosed fibrillary astrocytoma. The administration of thalidomide, which was suggested to be beneficial in the treatment of human cancers, had no substantial clinical effect on our patient. Autopsy studies revealed a diffuse infiltration of the frontal and temporal lobes of the right hemisphere, brainstem, and the leptomeninges covering the whole spinal cord by an astrocytic tumor, which showed features both of low-grade astrocytoma and glioblastoma multiforme. No mutations in the p53 and PTEN tumor suppressor genes were found; immunoreactivities for p53, PTEN, and EGFR could not be detected.
Journal of Neuro-Oncology 11/2001; 55(1):11-7. · 3.21 Impact Factor
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ABSTRACT: In an earlier study, we showed that heteroplasmy in the mitochondrial genome of gliomas sometimes occurs in a D-loop polycytosine tract. We extended this study by pairwise comparisons between glioma samples and adjacent brain tissue of 55 patients (50 glioblastomas, 1 astrocytoma WHO grade III, 4 astrocytomas WHO grade II). We used a combination of laser microdissection and PCR to detect and quantify variations in the polycytosine tract. New length variants undetectable in the adjacent brain tissue were observed in 5 glioblastomas (9%). In 2 of these cases, samples from a lower tumor stage (WHO grade II) could be analyzed and revealed the early occurrence of these mutations in both cases. Since the mitochondrial D-loop contains additional repeats and highly polymorphic non-coding sequences, we compared 17 glioblastomas with the corresponding blood samples of the same patients by direct sequencing of the complete D-loop. In 6 of these tumors (35%), instability was detected in 1 or 2 of 3 repeat regions; in 1 of these repeats, the instability was linked to a germline T-to-C transition. Furthermore, of 2 tumors (12%) 1 carried 1 and the other 9 additional transitions. In the latter patient, 6.7 kb of the protein coding mtDNA sequence were analyzed. Six silent transitions and 2 missense mutations (transitions) were found. All base substitutions appeared to be homoplasmic upon sequencing, and 89% occurred at known polymorphic sites in humans. Our data suggest that the same mechanisms that generate inherited mtDNA polymorphisms are strongly enhanced in gliomas and produce somatic mutations.
International Journal of Cancer 09/2001; 93(4):534-8. · 5.44 Impact Factor
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ABSTRACT: Several maternally inherited point mutations of the mitochondrial genome cause mitochondrial disorders, but the correlation between genotype and phenotype remains obscure in many cases. The same mutation may cause various diseases, probably because of a different tissue distribution.
To assess the role of random somatic segregation in generating interperson differences by analysis of an apparently neutral polymorphism.
Screening of 81 brain samples from subjects without mitochondrial disorders and selection of five necropsy cases showing a high level of heteroplasmy for the polymorphism.
A proportion of various distinct genotypes in the mtDNA pool of the tissues, identified by fluorescent PCR products, representing a short polycytosine tract of variable length in the mitochondrial displacement loop.
Differences were found between organs or groups of organs within subjects, pointing towards somatic segregation of mtDNA. In addition, marked differences of this organ distribution occurred between subjects, which cannot be explained by tissue specific selection.
The observed interperson differences can be explained by somatic segregation, which occurs randomly at various developmental stages. Besides tissue specific selection, this process might participate in the distribution of pathogenic mtDNA mutations.
Journal of Medical Genetics 06/2001; 38(5):312-7. · 6.36 Impact Factor
