In vivo quantification of human aqueous veins by enhanced depth imaging optical coherence tomography and optical coherence tomography angiography images.

AIM: To investigate the aqueous vein in vivo by using enhanced depth imaging optical coherence tomography (EDI-OCT) and optical coherence tomography angiography (OCTA). METHODS: In this cross-sectional comparative study, 30 healthy participants were enrolled. Images of the aqueous and conjunctival veins were captured by EDI-OCT and OCTA before and after water loading. The area, height, width, location depth and blood flow of the aqueous vein and conjunctival vein were measured by Image J software. RESULTS: In the static state, the area of the aqueous vein was 8166.7±3272.7 µm2, which was smaller than that of the conjunctival vein (13 690±7457 µm2, P<0.001). The mean blood flow density of the aqueous vein was 35.3%±12.6%, which was significantly less than that of the conjunctival vein (51.5%±10.6%, P<0.001). After water loading, the area of the aqueous vein decreased significantly from 8725.8±779.4 µm2 (baseline) to 7005.2±566.2 µm2 at 45min but rose to 7863.0±703.2 µm2 at 60min (P=0.032). The blood flow density of the aqueous vein decreased significantly from 41.2%±4.5% (baseline) to 35.4%±3.2% at 30min but returned to 45.6%±3.6% at 60min (P=0.021). CONCLUSION: The structure and blood flow density of the aqueous vein can be effectively evaluated by OCT and OCTA. These may become biological indicators to evaluate aqueous vein changes and aqueous outflow resistance under different interventions in glaucoma patients.

Analogs of microgravity: the function of Schlemm's canal, intraocular pressure and autonomic nervous during the head-down tilt test in healthy subjects.

AIM: To evaluate the ocular outcomes and to elucidate possible mechanisms underlying intraocular pressure (IOP) change following the head-down tilt (HDT) test. METHODS: The study included 21 participants at the Department of Ophthalmology of Tongji Hospital. Subjects received the test of I-care tonometry, enhanced depth imaging optical coherence tomography and heart rate variability (HRV) analysis before and after 15min HDT test. The lumen area of Schlemm's canal (SCAR), IOP, HRV were calculated. RESULTS: IOP increased significantly after 20° head down position from 14.0±3.0 to 17.0±3.3 mm Hg (P<0.001). SCAR decreased from 13449.0±5454.9 µm2 at sitting condition to 9576.6±4130.9 µm2 post 15min HDT test. High frequency (HF) indices increased significantly from 1462±865 Hz at baseline to 2128±824 Hz. Heart rate (HR) decreased significantly from 76±11.48 to 70±11.52 bpm after the HDT. The linear regression analysis showed that the difference of HF and SCAR significantly correlated with each other during the HDT (R2 =20%, P=0.04). CONCLUSION: These outcomes perform the first evidence of the activation of autonomic nervous system of HDT may cause the collapse of Schlemm's canal lumen, which in turn leading to the increased IOP.

Leukemia stem cells in drug resistance and metastasis.

OBJECTIVE: To review the central role of leukemia stem cells (LSCs) in drug resistance and metastasis, aiming to provide key insights into leukemogenic pathology and developing novel therapeutic strategies against the relapse of leukemia. DATA SOURCES: The data used in this review were obtained mainly from the studies reported in PubMed using the key terms "tumor-initiating cells", "leukemia stem cells", "drug resistance" and "metastasis". STUDY SELECTION: Relevant articles on studies of leukemia stem cells were selected. RESULTS: Increasing numbers of studies have suggested the importance of cancer stem cells (CSCs) in the initiation and maintenance of cancer, especially in leukemia. This review has summarized the origin, characteristics, isolation and identification of LSCs. It highlights the crucial role of LSCs in drug resistance and metastasis of leukemia by illustrating possible mechanisms and aims to provide novel therapeutic strategies for LSCs-targeted treatment. CONCLUSION: LSCs play a crucial role in drug resistance and metastasis of leukemia and new promising LSCs-targeted therapies warrant investigation in both experimental models and clinical practice.