Thomas Lars Andresen

Brachytherapy (BT) is routinely used in the treatment of various cancers. Current BT relies on the placement of large sources of radioactivity at the tumor site, requiring applicators that may cause local traumas and lesions. Further, they suffer from inflexibility in where they can be placed and some sources reside permanently in the body, causing potential long-term discomfort. These issues can be circumvented through injectable sources, prepared as biodegradable materials containing radionuclides that form solid seeds after administration. The level of radioactivity contained in such seeds must be sufficient to achieve substantial local irradiation. In this report, we investigate two different strategies for biodegradable BT seeds. The first strategy entails injectable seeds based on 103Pd-labeled palladium-gold alloy nanoparticles ([103Pd]PdAuNPs). These were prepared by combining [103Pd]PdH2Cl4 and AuHCl4, followed by lipophilic surface coating and dispersed in lactose octaisobutyrate and ethanol (LOIB:EtOH), in overall radiochemical yield (RCY) of 83%. With the second strategy, [103Pd]Pd-SSIB was prepared by conjugating the [16]aneS4 chelator with lipophilic sucrose septaisobutyrate (SSIB) followed by complexation with [103Pd]PdH2Cl4 (RCY = 99%) and mixed with LOIB:EtOH. [103Pd]Pd-SSIB was likewise formulated as injectable liquid forming seeds by mixing with LOIB. Both formulations reached activities of 1.0–1.5 GBq/mL and negligible release of radioactivity after injection of 100 µL (100–150 MBq) into aqueous buffer or mouse serum of less than 1% over one month. Both strategies for forming injectable BT seeds containing high 103Pd activity resulted in high radiolabeling yields, high activity per seed, and high activity retention. We consider both strategies suitable for BT, with the preferable strategy using a [16]aneS4 chelator due to its higher biodegradability.

Background and objectives: Brain capillary endothelial cells (BCECs) express transferrin receptor 1 (TfR1) to ensure sufficient iron transport into the brain across the blood-brain barrier (BBB). Our main objective was to examine adult mice subjected to dietary iron deficiency (ID) for possible changes in the content of TfR1 in BCECs and the influence thereof on the uptake and transport of high-affinity anti-transferrin receptor IgG1 antibodies (clone Ri7217). Material and methods: We subjected adult, female mice to dietary ID for 8 weeks. Iron and copper were measured using inductively coupled plasma mass spectrometry (ICP-MS) in various tissues, including total brain and isolated brain capillaries. Possible effects of ID on cerebral angioarchitecture were estimated using 3D confocal microscopy of optically cleared brain samples with endothelium labelled using intravenous injection of wheat germ agglutinin with subsequent machine learning-based segmentation and vascular tracing. TfR1 was quantified using ELISA. Ri7217 antibodies were conjugated with 1 nm nanogold and brain uptake quantified using ICP-MS. Results: ID significantly reduced the iron content in isolated brain capillaries, liver, spleen, kidney, heart and skeletal muscles. ID increased the copper content in the brain. Analysis of cerebral cortex angioarchitecture revealed no changes following dietary ID except for a minor increase in tortuosity of small-caliber vessels. TfR1 protein was unchanged in the total brain and isolated brain capillaries. In contrast, uptake of nanogold-conjugated Ri7217 increased in the total brain, the supernatant fraction of isolated brain capillaries representing the post-vascular compartment, liver, spleen, and dissected retinae. Conclusions: Targeting TfR1 in ID revealed increased uptake and transport across the BBB of Ri7217 antibodies. Possibly the elevated transport of transferrin receptors through BCECs is due to the increased trafficking of transferrin receptor-containing vesicles in ID, which appeared to have no major effects on the brain angioarchitecture.

Diseases caused by S. pneumoniae are the leading cause of child mortality. As antibiotic resistance of S. pneumoniae is rising, vaccination remains the most recommended solution. However, the existing pneumococcal polysaccharides vaccine (Pneumovax^® 23) proved only to induce T-independent immunity, and strict cold chain dependence of the protein conjugate vaccine impedes its promotion in developing countries, where infections are most problematic. Affordable and efficient vaccines against pneumococcus are therefore in high demand. Here, we present an intranasal vaccine Lipo⁺CPS12F&αGC, containing the capsular polysaccharides of S. pneumoniae 12F and the iNKT agonist α-galactosylceramide in cationic liposomes. In BALB/cJRj mice, the vaccine effectively activates iNKT cells and promotes B cells maturation, stimulates affinity-matured IgA and IgG production in both the respiratory tract and systemic blood, and displays sufficient protection both in vivo and in vitro. The designed vaccine is a promising, cost-effective solution against pneumococcus, which can be expanded to cover more serotypes and pathogens.

Cancer curing immune responses against heterogeneous solid cancers require that a coordinated immune activation is initiated in the antigen avid but immunosuppressive tumor microenvironment (TME). The plastic TME, and the poor systemic tolerability of immune activating drugs are, however, fundamental barriers to generating curative anticancer immune responses. Here, we introduce the CarboCell technology to overcome these barriers by forming an intratumoral sustained drug release depot that provides high payloads of immune stimulatory drugs selectively within the TME. The CarboCell thereby induces a hot spot for immune cell training and polarization and further drives and maintains the tumor-draining lymph nodes in an anticancer and immune activated state. Mechanistically, this transforms cancerous tissues, consequently generating systemic anticancer immunoreactivity. CarboCell can be injected through standard thin-needle technologies and has inherent imaging contrast which secure accurate intratumoral positioning. In particular, here we report the therapeutic performance for a dual-drug CarboCell providing sustained release of a Toll-like receptor 7/8 agonist and a transforming growth factor-β inhibitor in preclinical tumor models in female mice.