TY - JOUR A1 - Göring, Lukas A1 - Schumann, Sarah A1 - Müller, Jessica A1 - Buck, Andreas K. A1 - Port, Matthias A1 - Lassmann, Michael A1 - Scherthan, Harry A1 - Eberlein, Uta T1 - Repair of a-particle-induced DNA damage in peripheral blood mononuclear cells after internal ex vivo irradiation with \(^{223}\)Ra JF - European Journal of Nuclear Medicine and Molecular Imaging N2 - Purpose As α-emitters for radiopharmaceutical therapies are administered systemically by intravenous injection, blood will be irradiated by α-particles that induce clustered DNA double-strand breaks (DSBs). Here, we investigated the induction and repair of DSB damage in peripheral blood mononuclear cells (PBMCs) as a function of the absorbed dose to the blood following internal ex vivo irradiation with [\(^{223}\)Ra]RaCl2. Methods Blood samples of ten volunteers were irradiated by adding [\(^{223}\)Ra]RaCl2 solution with different activity concentrations resulting in absorbed doses to the blood of 3 mGy, 25 mGy, 50 mGy and 100 mGy. PBMCs were isolated, divided in three parts and either fixed directly (d-samples) or after 4 h or 24 h culture. After immunostaining, the induced γ-H2AX α-tracks were counted. The time-dependent decrease in α-track frequency was described with a model assuming a repair rate R and a fraction of non-repairable damage Q. Results For 25 mGy, 50 mGy and 100 mGy, the numbers of α-tracks were significantly increased compared to baseline at all time points. Compared to the corresponding d-samples, the α-track frequency decreased significantly after 4 h and after 24 h. The repair rates R were (0.24 ± 0.05) h−1 for 25 mGy, (0.16 ± 0.04) h−1 for 50 mGy and (0.13 ± 0.02) h−1 for 100 mGy, suggesting faster repair at lower absorbed doses, while Q-values were similar. Conclusion The results obtained suggest that induction and repair of the DSB damage depend on the absorbed dose to the blood. Repair rates were similar to what has been observed for irradiation with low linear energy transfer. KW - DSB damage KW - irradiation KW - α-Particle KW - γ-H2AX KW - repair Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-324557 VL - 49 IS - 12 ER - TY - JOUR A1 - Schumann, S. A1 - Eberlein, U. A1 - Lapa, C. A1 - Müller, J. A1 - Serfling, S. A1 - Lassmann, M. A1 - Scherthan, H. T1 - α-Particle-induced DNA damage tracks in peripheral blood mononuclear cells of [\(^{223}\)Ra]RaCl\(_{2}\)-treated prostate cancer patients JF - European Journal of Nuclear Medicine and Molecular Imaging N2 - Purpose One therapy option for prostate cancer patients with bone metastases is the use of [\(^{223}\)Ra]RaCl\(_{2}\). The α-emitter \(^{223}\)Ra creates DNA damage tracks along α-particle trajectories (α-tracks) in exposed cells that can be revealed by immunofluorescent staining of γ-H2AX+53BP1 DNA double-strand break markers. We investigated the time- and absorbed dose-dependency of the number of α-tracks in peripheral blood mononuclear cells (PBMCs) of patients undergoing their first therapy with [\(^{223}\)Ra]RaCl\(_{2}\). Methods Multiple blood samples from nine prostate cancer patients were collected before and after administration of [\(^{223}\)Ra]RaCl\(_{2}\), up to 4 weeks after treatment. γ-H2AX- and 53BP1-positive α-tracks were microscopically quantified in isolated and immuno-stained PBMCs. Results The absorbed doses to the blood were less than 6 mGy up to 4 h after administration and maximally 16 mGy in total. Up to 4 h after administration, the α-track frequency was significantly increased relative to baseline and correlated with the absorbed dose to the blood in the dose range < 3 mGy. In most of the late samples (24 h - 4 weeks after administration), the α-track frequency remained elevated. Conclusion The γ-H2AX+53BP1 assay is a potent method for detection of α-particle-induced DNA damages during treatment with or after accidental incorporation of radionuclides even at low absorbed doses. It may serve as a biomarker discriminating α- from β-emitters based on damage geometry. KW - γ-H2AX KW - DNA damage KW - nuclear medicine KW - dosimetry KW - α-Emitter KW - biokinetics KW - prostate cancer KW - [\(^{223}\)Ra]RaCl\(_{2}\) KW - 53BP1 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265462 SN - 1619-7089 VL - 48 IS - 9 ER - TY - THES A1 - Kreutzmann, Moritz Paul T1 - Untersuchung von Markern für oxidativen Stress und DNA-Schäden bei arterieller Hypertonie T1 - Investigation of markers for oxidative stress and DNA damage in arterial hypertension N2 - Patienten mit arterieller Hypertonie haben ein erhöhtes Risiko eine Tumorerkrankung, insbesondere Nierenzellkarzinome, zu entwickeln. Die arterielle Hypertonie ist über die Entstehung von oxidativem Stress mit der Entwicklung von DNA-Schäden verknüpft, wobei ein hochreguliertes Renin-Angiotensin-Aldosteron-System (RAAS) eine entscheidende Rolle einnimmt. Das Ziel dieser Arbeit war es zum einen Hypertoniker (HypAll) und gesunde Kontrollen und zum anderen gut (HypGut) und schlecht (HypSch) eingestellte Hypertoniker unter Berücksichtigung der eingenommenen Antihypertensiva bezüglich ihrer Level an oxidativem Stress und DNA-Schäden zu vergleichen. Zusätzlich erfolgte im Rahmen einer Längsschnittanalyse der intraindividuelle Vergleich unter den Hypertonikern. Hierfür erfolgte die Bestimmung von SHp, D-ROM und 3-Nitrotyrosin als Marker für oxidativen Stress im Plasma, von 8-oxodG, 15-F2t-Isoprostan und Malondialdehyd als Marker für oxidativen Stress im Urin und von γ-H2AX und Mikrokernen als Marker für DNA-Schäden in Lymphozyten. Dabei konnte ein erhöhter oxidativer Stress in der HypAll-Gruppe verglichen zu den Kontrollen anhand aller Marker für oxidativen Stress mit Ausnahme von Malondialdehyd festgestellt werden. Nach Altersadjustierung zeigte sich dieser Gruppenunterschied nur noch für die Proteinstressmarker SHp und 3-Nitrotyrosin signifikant. Bezüglich der Marker für DNA-Schäden ergab sich kein Unterschied zwischen HypAll und Kontrollen. Ebenso zeigte sich kein signifikanter Unterschied in den Leveln für oxidativen Stress und DNA-Schäden zwischen der HypGut- und HypSch-Gruppe. Zuletzt konnte im Rahmen der Längsschnittstudie ein positiver Zusammenhang zwischen der Entwicklung des Blutdrucks und des oxidativen Stresses anhand der Veränderung von D-ROM und des systolischen Blutdrucks beobachtet werden. Die teils nicht-signifikanten und teils mangelnden Unterschiede zwischen HypAll und Kontrollen sowie zwischen HypGut und HypSch sind am ehesten durch das besondere Patientengut, welches sich auch grundlegend von dem anderer vergleichbarer Studien unterscheidet, erklärbar. Die Patienten mit therapieresistenter Hypertonie (TRH) zeichnen sich durch eine langjährige Einnahme zahlreicher Antihypertensiva aus. Diese, insbesondere die RAAS-wirksamen, besitzen eine über die reine Blutdrucksenkung hinausgehende antioxidative und antigenotoxische Wirkung, welche vermutlich zu einer Angleichung der Level für oxidativen Stress und DNA-Schäden geführt hat. Um die Dynamik der Biomarker und den Einfluss der Antihypertensiva auf oxidativen Stress und DNA-Schäden besser zu verstehen, sind weitere Studien über einen längeren Beobachtungszeitraum sowie mit zusätzlich therapienaiven Hypertonikern sinnvoll. Die weitere Erforschung von Biomarkern, um sie im klinischen Alltag zur Verbesserung der Patientenbehandlung einsetzen zu können, ist notwendig. N2 - Patients with arterial hypertension are at an increased risk of developing tumors, especially renal cell carcinoma. Arterial hypertension is linked to the development of DNA damage through the development of oxidative stress, with an upregulated renin-angiotensin-aldosterone system (RAAS) playing a decisive role. The aim of this work was to compare 1. hypertensive patients (HypAll) and healthy controls and 2. hypertensive patients with good (HypGut) and poorly (HypSch) adjusted hypertension with regard to their level of oxidative stress and DNA damage. For this purpose, SHp, D-ROM and 3-nitrotyrosine were determined as markers for oxidative stress in plasma, 8-oxodG, 15-F2t-isoprostane and malondialdehyde as markers for oxidative stress in urine and γ-H2AX and micronuclei as markers for DNA damage in lymphocytes. An increased oxidative stress was found in the HypAll group compared to the controls as measured by all markers for oxidative stress with the exception of malondialdehyde. After adjusting for age, this group difference was only significant for the protein stress markers SHp and 3-nitrotyrosine. With regard to the markers for DNA damage, there was no difference between HypAll and controls. Also there was no significant difference in the levels of oxidative stress and DNA damage between the HypGut and HypSch groups. The partly insignificant and partly lacking differences between HypAll and controls as well as between HypGut and HypSch can best be explained by the special patient population, which is also fundamentally different from that of other comparable studies. The patients with therapy-resistant hypertension are characterized by long-term use of numerous antihypertensive drugs. These, especially the RAAS-effective ones, have an antioxidant and antigenotoxic effect that goes beyond the pure lowering of blood pressure. This has presumably led to an equalization of the levels for oxidative stress and DNA damage. In order to better understand the dynamics of the biomarkers and the influence of antihypertensive drugs on oxidative stress and DNA damage, further studies over a longer observation period and with additional therapy-naive hypertensive patients are useful. Further research into biomarkers is necessary so that they can be used in everyday clinical practice to improve patient treatment. KW - Oxidativer Stress KW - DNS-Schädigung KW - Biomarker KW - Hypertonie KW - Mikrokern KW - γ-H2AX Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-243380 ER - TY - JOUR A1 - Schumann, Sarah A1 - Scherthan, Harry A1 - Frank, Torsten A1 - Lapa, Constantin A1 - Müller, Jessica A1 - Seifert, Simone A1 - Lassmann, Michael A1 - Eberlein, Uta T1 - DNA Damage in Blood Leukocytes of Prostate Cancer Patients Undergoing PET/CT Examinations with [\(^{68}\)Ga]Ga-PSMA I&T JF - Cancers N2 - The aim was to investigate the induction and repair of radiation-induced DNA double-strand breaks (DSBs) as a function of the absorbed dose to the blood of patients undergoing PET/CT examinations with [68Ga]Ga-PSMA. Blood samples were collected from 15 patients before and at four time points after [68Ga]Ga-PSMA administration, both before and after the PET/CT scan. Absorbed doses to the blood were calculated. In addition, blood samples with/without contrast agent from five volunteers were irradiated ex vivo by CT while measuring the absorbed dose. Leukocytes were isolated, fixed, and stained for co-localizing γ-H2AX+53BP1 DSB foci that were enumerated manually. In vivo, a significant increase in γ-H2AX+53BP1 foci compared to baseline was observed at all time points after administration, although the absorbed dose to the blood by 68Ga was below 4 mGy. Ex vivo, the increase in radiation-induced foci depended on the absorbed dose and the presence of contrast agent, which could have caused a dose enhancement. The CT-dose contribution for the patients was estimated at about 12 mGy using the ex vivo calibration. The additional number of DSB foci induced by CT, however, was comparable to the one induced by 68Ga. The significantly increased foci numbers after [68Ga]Ga-PSMA administration may suggest a possible low-dose hypersensitivity. KW - DNA double-strand breaks KW - γ-H2AX KW - 53BP1 KW - nuclear medicine KW - dosimetry KW - Ga-68 KW - PSMA KW - PET/CT KW - contrast agent KW - prostate cancer Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-200585 SN - 2072-6694 VL - 12 IS - 2 ER - TY - JOUR A1 - Schuhmann, Sarah A1 - Eberlein, Uta A1 - Müller, Jessica A1 - Scherthan, Harry A1 - Lassmann, Michael T1 - Correlation of the absorbed dose to the blood and DNA damage in leukocytes after internal ex-vivo irradiation of blood samples with Ra-224 JF - EJNMMI Research N2 - Background: Irradiation with α-particles creates densely packed damage tracks along particle trajectories in exposed cells, including complex DNA damage and closely spaced double-strand breaks (DSBs) in hit nuclei. Here, we investigated the correlation of the absorbed dose to the blood and the number of α-induced DNA damage tracks elicited in human blood leukocytes after ex-vivo in-solution exposure with Ra-224. The aim was to compare the data to previously published data on Ra-223 and to investigate differences in DNA damage induction between the two radium isotopes. Results: Blood samples from three healthy volunteers were exposed ex-vivo to six different concentrations of Ra-224 dichloride. Absorbed doses to the blood were calculated assuming local energy deposition of all α- and β-particles of the Ra-224 decay chain, ranging from 0 to 127 mGy. γ-H2AX + 53BP1 DNA damage co-staining and analysis was performed on ethanol-fixed leukocytes isolated from the irradiated blood samples. For damage quantification, α-induced DNA damage tracks and small γ-H2AX + 53BP1 DSB foci were enumerated in the exposed leukocytes. This revealed a linear relationship between the frequency of α-induced γ-H2AX damage tracks and the absorbed dose to the blood, while the frequency of small γ-H2AX + 53BP1 DSB foci indicative of β-irradiation was similar to baseline values. Conclusions: Our data provide a first estimation of the DNA damage induced by Ra-224 in peripheral blood mononuclear cells. A comparison with our previously published Ra-223 data suggests that there is no difference in the induction of radiation-induced DNA damage between the two radium isotopes due to their similar decay properties. KW - 53BP1 KW - DNA damage KW - γ-H2AX KW - biological dosimetry KW - absorbed dose to the blood KW - α-emitter KW - Ra-224 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-176593 VL - 8 IS - 77 ER -