Chromatin Alterations in Leukocytes of First-episode Schizophrenic Patients

Abstract

Studies of peripheral blood leukocytes of schizophrenic patients have shown in electron microscopy (EM) that decondensation of the chromatin constitutes a biological marker indicating increased genomic expression. Since this increase depends on chromatin relaxation by dissociation of lysine-rich histone H1 from nucleosomes, with exposure of arginine residues of core histones, the ratio of arginine to lysine residues in each nucleus represents a reliable measure of activation. Lysine- and arginine-rich proteins are demonstrable in light microscopy (LM), differentially, as yellow and black, respectively, with the ammoniacal silver reaction (ASR). Application of ASR on leukocyte pellets before they are dehydrated and embedded in epoxy resins gives reliable results in semithin sections. In thin sections the ASR method localizes only the amino acid arginine by forming deposits of electron-opaque particles, visualized in the EM. Leukocytes of 12 first-episode schizophrenic patients and 5 controls were used. Light micrographs of the semithin sections were inserted in a personal computer. The percentage of lysine and arginine was measured in 300 nuclei per subject. Morphometry showed that lymphocytes of schizophrenic patients have increased ratios of arginine to lysine, compared to controls, indicating activation; neutrophils of the patients have even a higher ratio, indicating an abnormal condition of the genome. Chromatin conformational changes are also evident by phosphotungstic acid hematoxylin (PTAH) block staining, which reveals condensed chromatin as an electron-lucent area in the nuclei, and decondensed chromatin as an electron-dense area. Because decondensed chromatin is a biological marker of schizophrenia, the efficacy of these methods to demonstrate this particular state offers a tool for early diagnosis, since first-episode schizophrenic patients have a better prognosis when treatment is started promptly, at the beginning of the disease.

1Q12 Loci Movement in the Interphase Nucleus Under the Action of ROS Is an Important Component of the Mechanism That Determines Copy Number Variation of Satellite III (1q12) in Health and Schizophrenia

“…Small-sized 1q12 domains translocated to the central nucleus area; the nucleoli occupied a large area and approached the 1q12 region. SZ patients' lymphocytes activation has been repeatedly described in a number of papers (Hirata-Hibi et al, 1982;Kloukina-Pantazidou et al, 2010;Uranova et al, 2017). Some authors have described the nucleolus increase (Uranova et al, 2017).…”

Blood Chromatin as a Biosensor of the Epigenetic Milieu: A Tool for Studies in Living Psychiatric Patients

“…Measurements of H3K9ac revealed that schizophrenia subjects are less efficient in ‘opening up’ their chromatin given the same blood levels of the HDAC inhibitor valproic acid [5]. Another recent study has measured the extent of decondensation of the genome in PMBCs from living schizophrenia patients as measured by the level of exposed arginine residues in the core histones [48]. This investigation reports a higher ratio of arginines:lysines, indicating a more reactive genome in patients with a new onset of schizophrenia.…”