Christina Baun

Characterization of spontaneous air space enlargement in mice lacking microfibrillar-associated protein 4

Microfibrillar-associated protein 4 (MFAP4) is localized to elastic fibers in blood vessels and the interalveolar septa of the lungs and is further present in bronchoalveolar lavage. Mfap4 has been previously suggested to be involved in elastogenesis in the lung. We tested this prediction and aimed to characterize the pulmonary function changes and emphysematous changes that occur in Mfap4-deficient (Mfap4(-/-)) mice. Significant changes included increases in total lung capacity and compliance, which were evident in Mfap4(-/-) mice at 6 and 8 mo but not at 3 mo of age. Using in vivo breath-hold gated microcomputed tomography (micro-CT) in 8-mo-old Mfap4(-/-) mice, we found that the mean density of the lung parenchyma was decreased, and the low-attenuation area (LAA) was significantly increased by 14% compared with Mfap4(+/+) mice. Transmission electron microscopy (TEM) did not reveal differences in the organization of elastic fibers, and there was no difference in elastin content, but a borderline significant increase in elastin mRNA expression in 3-mo-old mice. Stereological analysis showed that alveolar surface density in relation to the lung parenchyma and total alveolar surface area inside of the lung were both significantly decreased in Mfap4(-/-) mice by 25 and 15%, respectively. The data did not support an essential role of MFAP4 in pulmonary elastic fiber organization or content but indicated increased turnover in young Mfap4(-/-) mice. However, Mfap4(-/-) mice developed a spontaneous loss of lung function, which was evident at 6 mo of age, and moderate air space enlargement, with emphysema-like changes.

[18F]Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET)/Computed Tomography (CT) in Suspected Recurrent Breast Cancer: A Prospective Comparative Study of Dual-Time-Point FDG-PET/CT, Contrast-Enhanced CT, and Bone Scintigraphy

PURPOSE To prospectively investigate the diagnostic accuracy of [(18)F]fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) with dual-time-point imaging, contrast-enhanced CT (ceCT), and bone scintigraphy (BS) in patients with suspected breast cancer recurrence. PATIENTS AND METHODS One hundred women with suspected recurrence of breast cancer underwent 1-hour and 3-hour FDG-PET/CT, ceCT, and BS within approximately 10 days. The study was powered to estimate the precision of the individual imaging tests. Images were visually interpreted using a four-point assessment scale, and readers were blinded to other test results. The reference standard was biopsy along with treatment decisions and clinical follow-up (median, 17 months). RESULTS FDG-PET/CT resulted in no false negatives and fewer false positives than the other imaging techniques. Accuracy of results were similar for 1-hour and 3-hour FDG-PET/CT. For distant recurrence, the area under the receiver operating curve was 0.99 (95% CI, 0.97 to 1) for FDG-PET/CT, 0.84 (95% CI, 0.73 to 0.94) for ceCT, and 0.86 (95% CI, 0.77 to 0.94) for the combined ceCT+BS. Of 100 patients, 22 (22%) were verified with distant recurrence, and 18 of these had bone involvement. Nineteen patients (19%) had local recurrence only. In exploratory analyses, diagnostic accuracy of FDG-PET/CT was better than ceCT alone or ceCT combined with BS in diagnosing distant, bone, and local recurrence, shown by a greater area under the receiver operating curve and higher sensitivity, specificity, and superior likelihood ratios. CONCLUSION FDG-PET/CT was accurate in diagnosing recurrence in breast cancer patients. It allowed for distant recurrence to be correctly ruled out and resulted in only a small number of false-positive cases. Exploratory findings suggest that FDG-PET/CT has greater accuracy than conventional imaging technologies in this patient group.

Conditional ablation of myeloid TNF increases lesion volume after experimental stroke in mice, possibly via altered ERK1/2 signaling

Microglia are activated following cerebral ischemia and increase their production of the neuro- and immunomodulatory cytokine tumor necrosis factor (TNF). To address the function of TNF from this cellular source in focal cerebral ischemia we used TNF conditional knock out mice (LysMcreTNFfl/fl) in which the TNF gene was deleted in cells of the myeloid lineage, including microglia. The deletion reduced secreted TNF levels in lipopolysaccharide-stimulated cultured primary microglia by ~93%. Furthermore, phosphorylated-ERK/ERK ratios were significantly decreased in naïve LysMcreTNFfl/fl mice demonstrating altered ERK signal transduction. Micro-PET using 18[F]-fluorodeoxyglucose immediately after focal cerebral ischemia showed increased glucose uptake in LysMcreTNFfl/fl mice, representing significant metabolic changes, that translated into increased infarct volumes at 24 hours and 5 days compared to littermates (TNFfl/fl). In naïve LysMcreTNFfl/fl mice cytokine levels were low and comparable to littermates. At 6 hours, TNF producing microglia were reduced by 56% in the ischemic cortex in LysMcreTNFfl/fl mice compared to littermate mice, whereas no TNF+ leukocytes were detected. At 24 hours, pro-inflammatory cytokine (TNF, IL-1β, IL-6, IL-5 and CXCL1) levels were significantly lower in LysMcreTNFfl/fl mice, despite comparable infiltrating leukocyte populations. Our results identify microglial TNF as beneficial and neuroprotective in the acute phase and as a modulator of neuroinflammation at later time points after experimental ischemia, which may contribute to regenerative recovery.

Persistent scarring and dilated cardiomyopathy suggest incomplete regeneration of the apex resected neonatal mouse myocardium--A 180 days follow up study.

Heart damage in mammals is generally considered to result in scar formation, whereas zebrafish completely regenerate their hearts following an intermediate and reversible state of fibrosis after apex resection (AR). Recently, using the AR procedure, one-day-old mice were suggested to have full capacity for cardiac regeneration as well. In contrast, using the same mouse model others have shown that the regeneration process is incomplete and that scarring still remains 21 days after AR. The present study tested the hypothesis that like in zebrafish, fibrosis in neonatal mammals could be an intermediate response before the onset of complete heart regeneration. Myocardial damage was performed by AR in postnatal day 1 C57BL/6 mice, and myocardial function and scarring assessed at day 180 using F-18-fluorodeoxyglucose positron emission tomography (FDG-PET) and histology, respectively. AR mice exhibited decreased ejection fraction and wall motion with increased end-diastolic and systolic volumes compared to sham-operated mice. Scarring with collagen accumulation was still substantial, with increased heart size, while cardiomyocyte size was unaffected. In conclusion, these data thus show that apex resection in mice results in irreversible fibrosis and dilated cardiomyopathy suggesting that cardiac regeneration is limited in neonatal mammals and thus distinct from the regenerative capacity seen in zebrafish.

Cardiac injury of the newborn mammalian heart accelerates cardiomyocyte terminal differentiation

After birth cardiomyocytes undergo terminal differentiation, characterized by binucleation and centrosome disassembly, rendering the heart unable to regenerate. Yet, it has been suggested that newborn mammals regenerate their hearts after apical resection by cardiomyocyte proliferation. Thus, we tested the hypothesis that apical resection either inhibits, delays, or reverses cardiomyocyte centrosome disassembly and binucleation. Our data show that apical resection rather transiently accelerates centrosome disassembly as well as the rate of binucleation. Consistent with the nearly 2-fold increased rate of binucleation there was a nearly 2-fold increase in the number of cardiomyocytes in mitosis indicating that the majority of injury-induced cardiomyocyte cell cycle activity results in binucleation, not proliferation. Concurrently, cardiomyocytes undergoing cytokinesis from embryonic hearts exhibited midbody formation consistent with successful abscission, whereas those from 3 day-old cardiomyocytes after apical resection exhibited midbody formation consistent with abscission failure. Lastly, injured hearts failed to fully regenerate as evidenced by persistent scarring and reduced wall motion. Collectively, these data suggest that should a regenerative program exist in the newborn mammalian heart, it is quickly curtailed by developmental mechanisms that render cardiomyocytes post-mitotic.

Chelation, formulation, encapsulation, retention, and in vivo biodistribution of hydrophobic nanoparticles labelled with 57Co-porphyrin: Oleylamine ensures stable chelation of cobalt in nanoparticles that accumulate in tumors

Background and motivation: While small molecules can be used in cancer diagnosis there is a need for imageable diagnostic NanoParticles (NPs) that act as surrogates for the therapeutic NPs. Many NPs are composed of hydrophobic materials so the challenge is to formulate hydrophobic imaging agents. To develop individualized medical treatments based on NP, a first step should be the selection of patients who are likely responders to the treatment as judged by imaging tumor accumulation of NPs. This requires NPs with the same size and structure as the subsequent therapeutic NPs but labelled with a long‐lived radionuclide. Cobalt isotopes are good candidates for NP labelling since 55Co has half‐life of 17.5h and positron energy of 570keV while 57Co (t1/2 271.6 d) is an isotope suited for preclinical single photon emission tomography (SPECT) to visualize biodistribution and pharmacokinetics of NPs. We used the hydrophobic octaethyl porphyrin (OEP) to chelate cobalt and to encapsulate it inside hydrophobic liquid NPs (LNPs). We hypothesized that at least two additional hydrophobic axial ligands (oleylamine, OA) must be provided to the OEP‐Co complex in order to encapsulate and retain Co inside LNP. Results: 1. Cobalt chelation by OEP and OA. The association constant of cobalt to OEP was 2.49×105 M−1 and the formation of the hexacoordinate complex OEP‐Co‐4OA was measured by spectroscopy. 2. NP formulation and characterization: LNPs were prepared by the fast ethanol injection method and were composed of a liquid core (triolein) surrounded by a lipid monolayer (DSPC:Cholesterol:DSPE‐PEG2000). The size of the LNPs loaded with the cobalt complex was 40±5nm, 3. Encapsulation of OEP‐Co‐OA: The loading capacity of OEP‐Co‐OA in LNP was 5mol%. 4. Retention of OEP‐57Co‐4OA complex in the LNPs: the positive effect of the OA ligands was demonstrated on the stability of the OEP‐57Co‐4OA complex, providing a half‐life for retention in PBS of 170h (7days) while in the absence of the axial OA ligands was only 22h. 5 Biodistribution Study: the in vivo biodistribution of LNP was studied in AR42J pancreatic tumor‐bearing mice. The estimated half‐life of LNPs in blood was about 7.2h. Remarkably, the accumulation of LNPs in the tumor was as high as 9.4% ID/g 24h after injection with a doubling time for tumor accumulation of 3.22h. The most important result was that the nanoparticles could indeed accumulate in the AR42J tumors up to levels greater than those of other NPs previously measured in the same tumor model, and at about half the values reported for the molecular agent 57Co‐DOTATATE. Conclusions: The additional hydrophobic chelator OA was indeed needed to obtain a stable octahedral OEP‐Co‐4OA. Cobalt was actually well‐retained inside LNP in the OEP‐Co‐4OA complex. The method described in the present work for the core‐labelling of LNPs with cobalt is now ready for labeling of NPs with 55Co, or indeed other hexadentate radionuclides of interest for preclinical in vivo PET‐imaging and radio‐therapeutics.

Formulation and in vivo biodistribution of 57Co-porphyrin-labelled hydrophobic liquid nanoparticles

European Journal of Nuclear Medicine and Molecular Imaging Volume 44, Supplement 2 10.1007/s00259-017-3822-1 This supplement was not sponsored by outside commercial interests. It was funded entirely by the association’s own resources DOI 10.1007/s00259-017-3822-1 S119 Eur J Nucl Med Mol Imaging (2017) 44 (Suppl 2):S119–S956

Diagnosing recurrent breast cancer: Accuracy and inter-rater agreement of FDG-PET/CT and bone scintigraphy

European Journal of Nuclear Medicine and Molecular Imaging Volume 44, Supplement 2 10.1007/s00259-017-3822-1 This supplement was not sponsored by outside commercial interests. It was funded entirely by the association’s own resources DOI 10.1007/s00259-017-3822-1 S119 Eur J Nucl Med Mol Imaging (2017) 44 (Suppl 2):S119–S956

Does an automatic PET infusion system actually deliver the prescribed dose

Hypothesis: We assessed in in vitro and in vivo models of ovarian cancer the therapeutic efficacy of 16F12 mAbs directed against Mullerian Inhibiting Substance type II receptor (MISRII) radiolabeled with 213Bi Methods: In vitro, both direct and bystander cytotoxic effects were measured using clonogenic assay and standard medium transfer protocol. Typically, Clonogenic survival was assessed in SK-OV-3 donor cells expressing MISRII and exposed for 90 min to 0.06-0.5MBq/mL of 16F12 213Bi-mAbs. Bystander cytotoxicity was measured in recipient cells grown in non-radioactive culture medium preconditioned for 2 hours in the presence of donor cells. DNA double strand breaks (DSBs) were measured in both donor and recipients cells using immunofluorescent detection of gamma-H2AX and of 53BP1. In vivo we explored in athymic nude mice bearing intraperitoneal (IP) MISRII-expressing AN3CA tumor the therapeutic efficacy of brief-intraperitoneal radioimmunotherapy (BIP-RIT, 12.95 37 MBq; 37MBq/mg) or of intraperitoneal RIT (IP-RIT; 2.96-12.95 MBq; 37MBq/mg) using 213Bi-16F12. BIP-RIT mimics hyperthermic intraperitoneal chemotherapy as used in clinic. It consists of intraperitoneal injection of high activities of radiolabeled mAbs followed 30 min later by wash of the peritoneal cavity with saline solution to remove unbound radioactivity. The biodistribution of radiolabeled antibodies following IP-RIT (12.95 MBq; 37MBq/mg) or BIP-RIT (37 MBq; 37MBq/mg) was assessed. Results: In vitro we showed in donor cells a strong direct cytotoxicity of 16F12 213Bi-mAbs. A significant bystander cytotoxicity was also measured in recipient cells. Genotoxic effects were also demonstrated as measured by the formation of DNA DSBs in both donor and recipient cells. In vivo, results of biodistribution indicated that tumour uptake of 213Bi-16F12 during BIP RIT was higher than after IP RIT. The tumour-to-blood uptake ratio was 9 versus 3, respectively, one hour post RIT while it decreased down to 3 and 1, respectively, three hours post-RIT. Finally, a similar delay in tumor growth was observed in mice treated with 12.95 MBq of 213Bi-16F12 following IP-RIT or treated with 37 MBq using BIP-RIT. Conclusions: We confirmed in vitro the therapeutic efficacy of newly developed 16F12 213Bi-mAbs. in vivo results indicate that similar therapeutic efficacy and lower toxicity could be obtained with BIP-RIT compared with IP-RIT. BIP-RIT could be a new tool in the therapy of peritoneal carcinomatosis. URI: Authors: LADJOHOUNLOU Riad PICHARD Alexandre DEHAYES E BOUDOUSQ Vincent BRUCHERTSEIFER Frank MORGENSTERN Alfred NAVARRO-TEULON Isabelle POUGET Jean-Pierre Publication Year: 2016 Science Areas: Health and consumer protection [1]European Journal of Nuclear Medicine and Molecular Imaging Volume 43, Supplement 1 10.1007/s00259-016-3484-4 This supplement was not sponsored by outside commercial interests. It was funded entirely by the association’s own resources. ABSTRACT DOI 10.1007/s00259-016-3484-4 Eur J Nucl Med Mol Imaging (2016) 43 (Suppl 1):S1–S734Background: In the context of the EORTC LungTech trial, a QA procedure including a PET/CT credentialing has been developed. This procedure will ultimately allow us to pool data from 23 institutions with the overall goal of investigating the impact of tumour motion on quantification. As no standardized procedure exists under respiratory conditions, we investigated the variability of 14 SUV metrics to assess their robustness over respiratory noise. Methods: The customized CIRS-008A phantom was scanned at 13 institutions. This phantom consists of a 18 cm long body, a rod attached to a motion actuator, and a sphere of either 1.5 or 2.5cm diameters. Body, rods and spheres were filled with homogeneous 18FDG solutions representative of activity concentrations in mediastinum, lung and tumour for a 70kg patient. Three respiratory patterns with peak-to-peak amplitudes and periods of 15mm/3sec, 15mm/6sec and 25mm/4sec were tested. Prior to scanning in respiratory condition, a 3D static PET/CT was acquired as reference. During motion, images were acquired using 3D or 4D gated PET(average image) according to institutional settings. 14 SUV(mean) metrics were obtained per acquisition varying VOI/ ROI shape and location. Three ROIs and three VOIs with respective radii of 0.5, 0.6 and 0.8cm were investigated. These ROIs/VOIs were first centred on the maximum activity voxel; a second analysis was made changing the location from the voxel to the region (ROI5voxels) or the volume (VOI7voxels) with the maximum value. Two additional VOIs were defined as 3D isocontours respectively at 70% and 50% of the maximum voxel value. The SUV metrics were normalized by the corresponding 3D static SUV. Converting to recovery coefficients (RC) allowed us to pool data from all institutions, while maintaining focus solely on motion. For each RC from each motion setting we calculated the mean over institutions, we then looked at the standard deviation (Sd) and spread of each averaged RC over each motion setting (formula [1], [2], Figure1). Results: For the institutions visited we found that RCVOI70% and RCVOI50%, yielded over the 14 metrics the lowest variability to motion with Sd of 0.04 and 0.03 respectively. The RCs based on ROIs/VOIs centered on a single voxel were less impacted by motion (Sd: 0.08) compared to region RCs (Sd: 0.14). The averaged Sd over the RCs based on VOIs and ROIs was 0.12 and 0.11 respectively. Conclusion: Quantification over breathing types depends on ROI/VOI definition. Variables based on SUV max thresholds were found the most robust against respiratory noise.

18F-Fluorodeoxymannose (FDM) is a Potential New Tracer for Inflammatory Bowel Disease

Hypothesis: We assessed in in vitro and in vivo models of ovarian cancer the therapeutic efficacy of 16F12 mAbs directed against Mullerian Inhibiting Substance type II receptor (MISRII) radiolabeled with 213Bi Methods: In vitro, both direct and bystander cytotoxic effects were measured using clonogenic assay and standard medium transfer protocol. Typically, Clonogenic survival was assessed in SK-OV-3 donor cells expressing MISRII and exposed for 90 min to 0.06-0.5MBq/mL of 16F12 213Bi-mAbs. Bystander cytotoxicity was measured in recipient cells grown in non-radioactive culture medium preconditioned for 2 hours in the presence of donor cells. DNA double strand breaks (DSBs) were measured in both donor and recipients cells using immunofluorescent detection of gamma-H2AX and of 53BP1. In vivo we explored in athymic nude mice bearing intraperitoneal (IP) MISRII-expressing AN3CA tumor the therapeutic efficacy of brief-intraperitoneal radioimmunotherapy (BIP-RIT, 12.95 37 MBq; 37MBq/mg) or of intraperitoneal RIT (IP-RIT; 2.96-12.95 MBq; 37MBq/mg) using 213Bi-16F12. BIP-RIT mimics hyperthermic intraperitoneal chemotherapy as used in clinic. It consists of intraperitoneal injection of high activities of radiolabeled mAbs followed 30 min later by wash of the peritoneal cavity with saline solution to remove unbound radioactivity. The biodistribution of radiolabeled antibodies following IP-RIT (12.95 MBq; 37MBq/mg) or BIP-RIT (37 MBq; 37MBq/mg) was assessed. Results: In vitro we showed in donor cells a strong direct cytotoxicity of 16F12 213Bi-mAbs. A significant bystander cytotoxicity was also measured in recipient cells. Genotoxic effects were also demonstrated as measured by the formation of DNA DSBs in both donor and recipient cells. In vivo, results of biodistribution indicated that tumour uptake of 213Bi-16F12 during BIP RIT was higher than after IP RIT. The tumour-to-blood uptake ratio was 9 versus 3, respectively, one hour post RIT while it decreased down to 3 and 1, respectively, three hours post-RIT. Finally, a similar delay in tumor growth was observed in mice treated with 12.95 MBq of 213Bi-16F12 following IP-RIT or treated with 37 MBq using BIP-RIT. Conclusions: We confirmed in vitro the therapeutic efficacy of newly developed 16F12 213Bi-mAbs. in vivo results indicate that similar therapeutic efficacy and lower toxicity could be obtained with BIP-RIT compared with IP-RIT. BIP-RIT could be a new tool in the therapy of peritoneal carcinomatosis. URI: Authors: LADJOHOUNLOU Riad PICHARD Alexandre DEHAYES E BOUDOUSQ Vincent BRUCHERTSEIFER Frank MORGENSTERN Alfred NAVARRO-TEULON Isabelle POUGET Jean-Pierre Publication Year: 2016 Science Areas: Health and consumer protection [1]European Journal of Nuclear Medicine and Molecular Imaging Volume 43, Supplement 1 10.1007/s00259-016-3484-4 This supplement was not sponsored by outside commercial interests. It was funded entirely by the association’s own resources. ABSTRACT DOI 10.1007/s00259-016-3484-4 Eur J Nucl Med Mol Imaging (2016) 43 (Suppl 1):S1–S734Background: In the context of the EORTC LungTech trial, a QA procedure including a PET/CT credentialing has been developed. This procedure will ultimately allow us to pool data from 23 institutions with the overall goal of investigating the impact of tumour motion on quantification. As no standardized procedure exists under respiratory conditions, we investigated the variability of 14 SUV metrics to assess their robustness over respiratory noise. Methods: The customized CIRS-008A phantom was scanned at 13 institutions. This phantom consists of a 18 cm long body, a rod attached to a motion actuator, and a sphere of either 1.5 or 2.5cm diameters. Body, rods and spheres were filled with homogeneous 18FDG solutions representative of activity concentrations in mediastinum, lung and tumour for a 70kg patient. Three respiratory patterns with peak-to-peak amplitudes and periods of 15mm/3sec, 15mm/6sec and 25mm/4sec were tested. Prior to scanning in respiratory condition, a 3D static PET/CT was acquired as reference. During motion, images were acquired using 3D or 4D gated PET(average image) according to institutional settings. 14 SUV(mean) metrics were obtained per acquisition varying VOI/ ROI shape and location. Three ROIs and three VOIs with respective radii of 0.5, 0.6 and 0.8cm were investigated. These ROIs/VOIs were first centred on the maximum activity voxel; a second analysis was made changing the location from the voxel to the region (ROI5voxels) or the volume (VOI7voxels) with the maximum value. Two additional VOIs were defined as 3D isocontours respectively at 70% and 50% of the maximum voxel value. The SUV metrics were normalized by the corresponding 3D static SUV. Converting to recovery coefficients (RC) allowed us to pool data from all institutions, while maintaining focus solely on motion. For each RC from each motion setting we calculated the mean over institutions, we then looked at the standard deviation (Sd) and spread of each averaged RC over each motion setting (formula [1], [2], Figure1). Results: For the institutions visited we found that RCVOI70% and RCVOI50%, yielded over the 14 metrics the lowest variability to motion with Sd of 0.04 and 0.03 respectively. The RCs based on ROIs/VOIs centered on a single voxel were less impacted by motion (Sd: 0.08) compared to region RCs (Sd: 0.14). The averaged Sd over the RCs based on VOIs and ROIs was 0.12 and 0.11 respectively. Conclusion: Quantification over breathing types depends on ROI/VOI definition. Variables based on SUV max thresholds were found the most robust against respiratory noise.