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Background: Angiogenesis is defined as a new blood vessel sprouting from pre-existing vessels, and the sprouting angiogenesis is the start phase of angiogenesis, which is critical for both physiological and pathological processes, such as embryonic development, organ growth, wound healing, tumor growth, diabetic retinopathy and age-related macular degeneration. Better understanding of the mechanisms of sprout angiogenesis will provide a rationale for the treatments of these angiogenesis related diseases.Methods: mT/mG tool mice are crossed with Apln-CreERT mice to generate Apln-CreERT: mT/mG mice, then we used neonatal retinal angiogenesis model to observe the angiogenic pattern of Apln-CreERT:mT/mG mice compared with Cdh5-CreERT:mT/mG mice. FACS analysis was used to sort eGFP and tdTomato endothelial cells (ECs) for measuring Apelin and Cdh5 expression. Retinal sprouting angiogenesis pattern was also observed at different neonatal time when induced by tamoxifen and at hypoxia condition, as well as in vivo tumor in real-time angiogenesis in a dorsal skinfold window chamber in Apln-CreERT:mT/mG mice.Results: Apln-CreERT:mT/mG mice exhibited eGFP signal only in the sprouting angiogenesis, with less eGFP expression in the retinal "optic nerve" area than in that of Cdh5-CreERT: mT/mG mice, which might be due to relative mature vessels in the "optic nerve" area. The ECs sorted by FACS confirmed that the Apelin expression level was higher in eGFP ECs than tdTomato ECs of "optic nerve" area. Further we found that GFP-labeled sprouting angiogenesis decreased gradually following tamoxifen administration from P5-P7, but increased significantly during hypoxia in Apln-CreERT:mT/mG mice. At last, using Apln-CreERT:mT/mG mice we found tumor sprouting angiogenesis in dorsal skinfold, but not in the normal skinfold tissue.Conclusions: Apln-CreERT:mT/mG mouse line is a useful tool to differentiate sprouting angiogenesis from whole blood vessels in the investigation of retinal and tumor sprouting angiogenesis in vivo. [ABSTRACT FROM AUTHOR]

The pathogenesis of temporomandibular joint osteoarthritis (TMJOA) is closely associated with mechanical friction, which leads to the up-regulation of inflammatory mediators and the degradation of articular cartilage. Injectable drug-loaded microparticles have attracted widespread interest in intra-articular treatment of TMJOA by providing lubrication and facilitating localized drug delivery. Herein, a hyaluronic acid-based microparticle is developed with excellent lubrication properties, drug loading capacity, antioxidant activity, and anti-inflammatory effect for the treatment of TMJOA. The microparticles are facilely prepared by the self-assembly of 3-aminophenylboronic acid-modified hyaluronic acid (HP) through hydrophobic interaction in an aqueous solution, which can further encapsulate diol-containing drugs through dynamic boronate ester bonds. The resulting microparticles demonstrate excellent injectability, lubrication properties, radical scavenging efficiency, and antibacterial activity. Additionally, the drug-loaded microparticles exhibit a favorable cytoprotective effect on chondrocyte cells in vitro under an oxidative stress microenvironment. In vivo experiments validate that intra-articular injection of drug-loaded microparticles effectively alleviates osteoporosis-like damage, suppresses inflammatory response, and facilitates matrix regeneration in the treatment of TMJOA. The HP microparticles demonstrate excellent injectability and encapsulation capacity for diol-containing drugs, highlighting its potential as a versatile drug delivery vehicle in the intra-articular treatment of TMJOA., Competing Interests: Competing interests: The authors declare that they have no competing interests., (Copyright © 2024 Lei Liu et al.)

Background: Angiogenesis is defined as a new blood vessel sprouting from pre-existing vessels, and the sprouting angiogenesis is the start phase of angiogenesis, which is critical for both physiological and pathological processes, such as embryonic development, organ growth, wound healing, tumor growth, diabetic retinopathy and age-related macular degeneration. Better understanding of the mechanisms of sprout angiogenesis will provide a rationale for the treatments of these angiogenesis related diseases., Methods: mT/mG tool mice are crossed with Apln-CreERT mice to generate Apln-CreERT: mT/mG mice, then we used neonatal retinal angiogenesis model to observe the angiogenic pattern of Apln-CreERT:mT/mG mice compared with Cdh5-CreERT:mT/mG mice. FACS analysis was used to sort eGFP and tdTomato endothelial cells (ECs) for measuring Apelin and Cdh5 expression. Retinal sprouting angiogenesis pattern was also observed at different neonatal time when induced by tamoxifen and at hypoxia condition, as well as in vivo tumor in real-time angiogenesis in a dorsal skinfold window chamber in Apln-CreERT:mT/mG mice., Results: Apln-CreERT:mT/mG mice exhibited eGFP signal only in the sprouting angiogenesis, with less eGFP expression in the retinal "optic nerve" area than in that of Cdh5-CreERT: mT/mG mice, which might be due to relative mature vessels in the "optic nerve" area. The ECs sorted by FACS confirmed that the Apelin expression level was higher in eGFP ECs than tdTomato ECs of "optic nerve" area. Further we found that GFP-labeled sprouting angiogenesis decreased gradually following tamoxifen administration from P5-P7, but increased significantly during hypoxia in Apln-CreERT:mT/mG mice. At last, using Apln-CreERT:mT/mG mice we found tumor sprouting angiogenesis in dorsal skinfold, but not in the normal skinfold tissue., Conclusions: Apln-CreERT:mT/mG mouse line is a useful tool to differentiate sprouting angiogenesis from whole blood vessels in the investigation of retinal and tumor sprouting angiogenesis in vivo.