Translational research of boron neutron capture therapy for spinal cord gliomas using rat model

Boron neutron capture therapy (BNCT) is a type of targeted particle radiation therapy with potential applications at the cellular level. Spinal cord gliomas (SCGs) present a substantial challenge owing to their poor prognosis and the lack of effective postoperative treatments. This study evaluated the efficacy of BNCT in a rat SCGs model employing the Basso, Beattie, and Bresnahan (BBB) scale to assess postoperative locomotor activity. We confirmed the presence of adequate in vitro boron concentrations in F98 rat glioma and 9L rat gliosarcoma cells exposed to boronophenylalanine (BPA) and in vivo tumor boron concentration 2.5 h after intravenous BPA administration. In vivo neutron irradiation significantly enhanced survival in the BNCT group when compared with that in the untreated group, with a minimal BBB scale reduction in all sham-operated groups. These findings highlight the potential of BNCT as a promising treatment option for SCGs.

Nonclinical pharmacodynamics of boron neutron capture therapy using direct intratumoral administration of a folate receptor targeting novel boron carrier

Background

Boron neutron capture therapy (BNCT) is a precise particle radiation therapy known for its unique cellular targeting ability. The development of innovative boron carriers is crucial for the advancement of BNCT technologies. Our previous study demonstrated the potential of PBC-IP administered via convection-enhanced delivery (CED) in an F98 rat glioma model. This approach significantly extended rat survival in neutron irradiation experiments, with half achieving long-term survival, akin to a cure, in a rat brain tumor model. Our commitment to clinical applicability has spurred additional nonclinical pharmacodynamic research, including an investigation into the effects of cannula position and the time elapsed post-CED administration.

Methods

In comprehensive in vivo experiments conducted on an F98 rat brain tumor model, we meticulously examined the boron distribution and neutron irradiation experiments at various sites and multiple time intervals following CED administration.

Results

The PBC-IP showed substantial efficacy for BNCT, revealing minimal differences in tumor boron concentration between central and peripheral CED administration, although a gradual decline in intratumoral boron concentration post-administration was observed. Therapeutic efficacy remained robust, particularly when employing cannula insertion at the tumor margin, compared to central injections. Even delayed neutron irradiation showed notable effectiveness, albeit with a slightly reduced survival period. These findings underscore the robust clinical potential of CED-administered PBC-IP in the treatment of malignant gliomas, offering adaptability across an array of treatment protocols.

Conclusions

This study represents a significant leap forward in the quest to enhance BNCT for the management of malignant gliomas, opening promising avenues for clinical translation.

ET-4 BASIC RESEARCH OF BORON NEUTRON CAPTURE THERAPY USING A NOVEL BORON COMPOUND TARGETED TO INTEGRIN

Background

Boron neutron capture therapy (BNCT) is a particle radiation modality capable of selectively destroying tumor cells. The most commonly used boron compound for BNCT is boronphenylalanine (BPA). BPA is taken up into the tumor cell via the L-type aminoacid transporter (LAT-1). However, there are some BPA-refractory situations. Therefore, a novel boron compound is expected to improve the therapeutic performance of BNCT. We focused on integrinαvβ3, which is overexpressed in malignant gliomas as in many cancer cells, and have developed cRGD-MID-AC, a conjugate of cyclic RGD (cRGD), which selectively inhibited integrinαvβ3, and MID-AC, which we have already reported as effective on BNCT as BPA as a boron compound in F98 rat glioma models. We evaluated the efficacy of BNCT using this novel compound.Methods: F98 glioma cells were exposed to BPA, cRGD-MID-AC, and cRGD-MID for cellular uptake and neutron irradiation experiment. Intracellular boron concentrations and compound biological effectiveness (CBE) for each boron compound was calculated. After intravenous administration (i.v.) of cRGD-MID-AC or BPA, the biodistribution of boron compounds was measured and neutron irradiation experiment were performed in F98 rat glioma models.

Results

Intracellular boron concentrations of BPA and cRGD-MID-AC were increased gradually at all exposed time, and CBE for cRGD-MID-AC was comparable to that for BPA. In cRGD-MID-AC, the boron concentration in the tumor was the highest at 8 h after i.v. and tended to be retained longer at 24h. In vivo neutron irradiation experiment, long-term survival was observed only in the group irradiated 8 h after cRGD-MID-AC i.v.. These experiments suggest that cRGD-MID-AC has sufficient cell-killing effect and may be more effective in vivo.

Conclusion

cRGD-MID-AC has a tumor accumulation mechanism different from that of BPA, and could be an effective boron carrier in BNCT for malignant gliomas.

Intra-Aneurysmal Coil Embolization of a Ruptured Distal Posterior Inferior Temporal Artery Aneurysm: A Case Report

Objective

We report a case of a ruptured aneurysm at the posterior inferior temporal artery (PITA) of the posterior cerebral artery (PCA) treated by intra-aneurysmal coil embolization.

Case Presentation

A 93-year-old man presented with disturbance of consciousness. Angiography revealed a 3-mm aneurysm in the distal PITA of the left PCA. He was diagnosed with subarachnoid hemorrhage and intracerebral hemorrhage due to a ruptured aneurysm. This aneurysm was occluded by intra-aneurysmal coil embolization with preservation of the PITA.

Conclusion

Distal PITA aneurysm of the PCA is rare. Complete occlusion and preservation of the parent artery were achieved by intra-aneurysmal coil embolization, which may be an effective therapeutic option for such aneurysms.