Radiosensitisation by olaparib through focused ultrasound delivery in a diffuse midline glioma model.

BACKGROUND AND PURPOSE: Diffuse midline glioma H3K27-altered (DMG) is an aggressive, inoperable, predominantly paediatric brain tumour. Treatment strategies are limited, resulting in a median survival of only 11 months. Currently, radiotherapy (RT), often combined with temozolomide, is considered the standard of care but remains palliative, highlighting the urgency for new therapies. Radiosensitisation by olaparib, an inhibitor of PARP1 and subsequently PAR-synthesis, is a promising treatment option. We assessed whether PARP1 inhibition enhances radiosensitivity in vitro and in vivo following focused ultrasound mediated blood-brain barrier opening (FUS-BBBO). METHODS: Effects of PARP1 inhibition were evaluated in vitro using viability, clonogenic, and neurosphere assays. In vivo olaparib extravasation and pharmacokinetic profiling following FUS-BBBO was measured by LC-MS/MS. Survival benefit of FUS-BBBO combined with olaparib and RT was assessed using a patient-derived xenograft (PDX) DMG mouse model. RESULTS: Treatment with olaparib in combination with radiation delayed tumour cell proliferation in vitro through the reduction of PAR. Prolonged exposure of low olaparib concentration was more efficient in delaying cell growth than short exposure of high concentration. FUS-BBBO increased olaparib bioavailability in the pons by 5.36-fold without observable adverse effects. A Cmax of 54.09 µM in blood and 1.39 µM in the pontine region was achieved following administration of 100 mg/kg olaparib. Although RT combined with FUS-BBBO mediated olaparib extravasation delayed local tumour growth, survival benefits were not observed in an in vivo DMG PDX model. CONCLUSIONS: Olaparib effectively radiosensitises DMG cells in vitro and reduces primary tumour growth in vivo when combined with RT. Further studies are needed to investigate the therapeutic benefit of olaparib in suitable preclinical PDX models.

[Driving with Alzheimer's disease]. / Autorijden met de ziekte van Alzheimer.

OBJECTIVE: To summarise the available literature on driving with Alzheimer's disease (AD) and to investigate the relationship between driving and cognitive functioning. DESIGN: Literature review. METHOD: A systematic search of the electronic databases PubMed/MEDLINE was conducted to select the relevant literature on the driving competence of patients with Alzheimer's disease. RESULTS: A total of 31 studies were selected that investigated driving competence in AD using either an on-road driving assessment or a driving simulator. The driving competence of patients with AD was less accurate compared with controls. The most commonly made errors included errors in staying in lane, lane changing, slower reaction times, and more fluctuations in speed. Cognitive functioning was more predictive of driving competence than a diagnosis of AD alone. CONCLUSION: Based on the available literature it is difficult to determine when patients with AD should be restricted in their driving. In addition, there is currently no consensus on which neuropsychological tests are useful in clinical practice to predict driving competence. Specific practical guidelines that can be implemented in daily practice are still lacking.