近期主題 Current Topic
Ultrasound in tumor immunotherapy
Immunotherapy has considerable potential in eliminating cancers by activating the host's own immune system, while the thermal and mechanical effects of ultrasound have various applications in tumor therapy. Hyperthermia, ablation, histotripsy, and microbubble stable/inertial cavitation can alter the tumor microenvironment to enhance immunoactivation to inhibit tumor growth. Microbubble cavitation can increase vessel permeability and thereby improve the delivery of immune cells, cytokines, antigens, and antibodies to tumors. Violent microbubble cavitation can disrupt tumor cells and efficiently expose them to numerous antigens so as to promote the maturity of antigen-presenting cells and subsequent adaptive immune-cell activation.
Tumor vascular normalization
The dysfunctional tumor vasculature limits the efficiency of oxygenation and drug delivery to reduce treatment outcome. A concept of tumor vascular normalization (VN) inhibits angiogenesis to improve vessel maturity, blood perfusion, and oxygenation. The efficiency of drug delivery and penetration is increased by enhancing perfusion and reducing interstitial fluid pressure during the time window of VN. To repair tumor vessels without altering vessel density, we proposed to induce tumor VN by local oxygen release via oxygen microbubbles with ultrasound. The enhanced tumor oxygenation inhibited HIF-1α/VEGF pathway to improve the morphology and function of tumor vasculature for drug penetration.
Stroke-reperfusion injury
Ischemic stroke-reperfusion (S/R) injury is a crucial issue in the protection of brain function after thrombolysis. The vasodilation induced by ultrasound (US)-stimulated microbubble cavitation has been applied to reduce S/R injury through sonoperfusion. The present study uses oxygen-loaded microbubbles (OMBs) with US stimulation to provide sonoperfusion and local oxygen therapy with the aim of enhancing microcirculation and cell repair for the reduction of brain infarct size and neuroprotection after S/R.
Combinding radiotherapy
Hypoxia-induced tumor radioresistance is a critical concern in radiotherapy. However, the tumor's hypoxic microenvironment reduces the production of reactive oxygen species (ROS) , inhibiting the effectiveness of radiotherapy and increasing the risk of tumor recurrence. Therefore, this project aims to combine oxygen-loaded microbubbles (OMBs) with radiotherapy, which can locally release oxygen within tumors to increase the production of ROS, resulting in the enhancement of the radiotherapeutic effect. Additionally, the correlation between oxygen, the production of different types of ROS, and tumor cell apoptosis would be evaluated. It is expected that in the future, microbubbles can be engineered to carry various gases or drugs, allowing for precise control of specific ROS production, thereby enhancing the efficiency of radiotherapy in inhibiting tumor growth.
