Oxidatively-induced DNA base damage and base excision repair abnormalities in siblings of individuals with bipolar disorder DNA damage and repair in bipolar disorder.

Previous evidence suggests elevated levels of oxidatively-induced DNA damage, particularly 8-hydroxy-2'-deoxyguanosine (8-OH-dG), and abnormalities in the repair of 8-OH-dG by the base excision repair (BER) in bipolar disorder (BD). However, the genetic disposition of these abnormalities remains unknown. In this study, we aimed to investigate the levels of oxidatively-induced DNA damage and BER mechanisms in individuals with BD and their siblings, as compared to healthy controls (HCs). 46 individuals with BD, 41 siblings of individuals with BD, and 51 HCs were included in the study. Liquid chromatography-tandem mass spectrometry was employed to evaluate the levels of 8-OH-dG in urine, which were then normalized based on urine creatinine levels. The real-time-polymerase chain reaction was used to measure the expression levels of 8-oxoguanine DNA glycosylase 1 (OGG1), apurinic/apyrimidinic endonuclease 1 (APE1), poly ADP-ribose polymerase 1 (PARP1), and DNA polymerase beta (POLß). The levels of 8-OH-dG were found to be elevated in both individuals with BD and their siblings when compared to the HCs. The OGG1 and APE1 expressions were downregulated, while POLß expressions were upregulated in both the patient and sibling groups compared to the HCs. Age, smoking status, and the number of depressive episodes had an impact on APE1 expression levels in the patient group while body mass index, smoking status, and past psychiatric history had an impact on 8-OH-dG levels in siblings. Both individuals with BD and unaffected siblings presented similar abnormalities regarding oxidatively-induced DNA damage and BER, suggesting a link between abnormalities in DNA damage/BER mechanisms and familial susceptibility to BD. Our findings suggest that targeting the oxidatively-induced DNA damage and BER pathway could offer promising therapeutic strategies for reducing the risk of age-related diseases and comorbidities in individuals with a genetic predisposition to BD.

Development and validation of an LC-MS/MS method for D- and L-2-hydroxyglutaric acid measurement in cerebrospinal fluid, urine and plasma: application to glioma.

Aim: IDH mutations have been identified as frequent molecular lesions in several tumor types, particularly in gliomas. As a putative marker of IDH mutations, elevated D-2-HG has been reported in glioma, acute myeloid leukemia and intrahepatic cholangiocarcinoma. Excessive production of L-2-HG has also been described in renal cell carcinoma and 2-hydroxyaciduria. Materials & methods: The authors present a fully optimized stable isotope dilution multiple reaction monitoring method for quantification of D-/L-2-HG using LC-MS/MS. This is the first method validation study performed on cerebrospinal fluid, plasma and urine demonstrating clinical applicability with samples from glioma patients. Results & conclusion: This method validation study showed high accuracy and precision with low limit of detection and limit of quantification values. The authors believe that the presented approach is highly applicable for basic and clinical research on related pathologies.

Minimally Invasive Detection of IDH1 Mutation With Cell-Free Circulating Tumor DNA and D-2-Hydroxyglutarate, D/L-2-Hydroxyglutarate Ratio in Gliomas.

Isocitrate dehydrogenase-1 (IDH1) mutation is accepted as one of the earliest events in tumorigenesis in gliomas. This mutation causes preferential accumulation of D- relative to L-enantiomer of 2-hydroxyglutarate (2-HG). Minimally invasive techniques to detect IDH1 mutation may prove useful for clinical practice. We adopted 2 different diagnostic approaches to detect IDH1 mutation status in glioma patients: Evaluation of D- and L-2-HG levels in cerebrospinal fluid (CSF), urine, and plasma, and identification of IDH1 mutation using cell-free circulating tumor DNA (ctDNA) in CSF and plasma. Forty-nine glioma patients in different stages were included. Levels of D- and L-2-HG were determined using liquid chromatography-tandem mass spectrometry; IDH1 R132H mutation was determined by digital-PCR. D-2-HG levels and D/L-2-HG ratio (rDL) in CSF and rDL in plasma were significantly higher in the mutant group than in the wild-type group (p = 0.029, 0.032, 0.001, respectively). The IDH1 mutation detection rates in CSF- and plasma-ctDNA were 63.2% and 25.0%, respectively. These data indicate that D-2-HG values in CSF and rDL in plasma and CSF can be considered as significant contributors to the identification of IDH1 mutation status. In addition, detection of IDH1 mutation in CSF-ctDNA from glioma patients provides a basis for future use of ctDNA for minimally invasive clinical assessment of gliomas.

Association between early oxidative DNA damage and iron status in women with gestational diabetes mellitus.

This study aims to assess the relationship between oxidative DNA damage and iron status in women with gestational diabetes mellitus (GDM) compared to those with normal glucose tolerance in the first and the second trimesters of pregnancy. Maternal serum and urine samples were collected in the 11th-14th weeks and the 24th-28th weeks of gestation. In addition to oral glucose tolerance test in the second trimester, fasting blood glucose, HbA1c, ferritin and hemoglobin levels were measured in blood samples. Urinary levels of oxidative DNA damage products 8-hydroxy-2'-deoxyguanosine (8-OH-dG) and 8,5'-cyclo-2'-deoxyadenosines (S-cdA, R-cdA) were determined using liquid chromatography-tandem mass spectrometry with isotope-dilution. In the first trimester, urinary 8-OH-dG levels were found higher in the GDM group (n = 33) than in the control group (n = 84) (p = 0.006). R-cdA and S-cdA levels were not significantly different between the two groups (p = 0.794 and p = 0.792 respectively). When the cases were stratified according to their first trimester ferritin levels, women with ≥50th centile (≥130 ng/mL) demonstrated higher levels of 8-OH-dG and R-cdA than those under <50th centile (p = 0.034, p = 0.009). In the GDM group, there was a positive correlation between the second trimester 8-OH-dG and ferritin and 1st-hour glucose levels (p = 0.014, p = 0.020). This is the first study where oxidative DNA damage is evaluated in both early and late periods of pregnancy. Our findings reveal an association between GDM and iron status and oxidative DNA damage.