A novel rat model of cerebral small vessel disease and evaluation by super-resolution ultrasound imaging.

Cerebral small vessel disease (CSVD), which causes cognitive, functional and emotional decline, is related to stroke events, and it is a major cause of Alzheimer's disease. In the social context of an aging population, the incidence of CSVD is on the rise yearly, and the exact pathogenesis is still controversial and remains unclear. Exploring the pathological mechanism of CSVD on the histological level using animal models is important for the investigation of new clinical diagnostic methods and treatment options. The existing surgical CSVD model preparation methods are difficult to operate and cannot control the injury location or degree. This study used ultrasound combined with microbubbles (MBs) to induce an easy-to-operate and non-invasive animal model of CSVD with controllable location and degree. The rat model was evaluated from the perspective of histology, ethology, and imageology, respectively. In addition, we utilized super-resolution ultrasound imaging (SR-US) technology to directly observe the microvessels of the model. The histological results showed that the modeling was successful in the preset position, and neurology deficits were observed in 62.5% of 8 rats. The SR-US results of one rat showed that compared with the non-sonication region, the number of cerebral small blood vessels discovered in the sonication area was reduced (43 vs 11), the blood flow speed decreased significantly (p 0.001), and blood flow volume decreased (144.7 vs 11.7 µL/s) because of vasoconstriction. This study provides a new modeling method with controllable damage location and degree for the study of CSVD, and SR-US is found to be an effective evaluation method, which can directly assess the hemodynamic changes of CSVD in vivo.

Specific diagnosis of lymph node micrometastasis in breast cancer by targeting activatable near-infrared fluorescence imaging.

Axillary lymph node metastasis has always been defined as the most important prognostic factor in the treatment of early breast cancer. Ultrasound and MRI can detect only 10% of lymph node micrometastases in early breast cancer. Therefore, it is crucial to detect early breast cancer with lymph node metastasis, however, there is no current examination method for accurate diagnosis. When breast cancer presents a malignant tendency, colony stimulating factor-1 and chemokine CCL-2 absorb mononuclear cells from the surrounding environment and differentiate into M2 Tumor associated macrophages (TAM), which increase the invasion of tumor cells and further promote the development of tumors. Mannose, as a simple natural ligand, can selectively bind to TAM surface CD206 (macrophage mannose receptor, MMR). In this study, mannose was connected with near infrared dye (NIR) IR780 via disulfide bond to obtain Mannose-IR780 conjugate (MR780), which was further self-assembled into near infrared nanoprobe (MR780 NPs) with quenched fluorescence. When selectively targeting CD206 highly expressed on the surface of TAM, disulfide bond was cleaved by the glutathione enriched in the microenvironment, resulting in fluorescence recovery, thus achieving NIR fluorescence molecular imaging of TAM and diagnosis of tumor lymph node metastasis in mouse models. Our findings suggest that targeted imaging of TAM enable noninvasive and sensitive detection of metastatic lymph nodes in vivo, which is instructive for tumor therapy.

Treating tumors with minimally invasive therapy: A review.

With high level of morbidity and mortality, tumor is one of the deadliest diseases worldwide. Aiming to tackle tumor, researchers have developed a lot of strategies. Among these strategies, the minimally invasive therapy (MIT) is very promising, for its capability of targeting tumor cells and resulting in a small incision or no incisions. In this review, we will first illustrate some mechanisms and characteristics of tumor metastasis from the primary tumor to the secondary tumor foci. Then, we will briefly introduce the history, characteristics, and advantages of some of the MITs. Finally, emphasis will be, respectively, focused on an overview of the state-of-the-art of the HIFU-, PDT-, PTT-and SDT-based anti-tumor strategies on each stage of tumor metastasis.