Over the past decades, a number of bone tissue engineering (BTE) approaches have been developed to address substantial challenges in the management of critical size bone defects. Although the majority of BTE strategies developed in the laboratory have been limited due to lack of clinical relevance in translation, primary prerequisites for the construction of vascularized functional bone grafts have gained confidence owing to the accumulated knowledge of the osteogenic, osteoinductive, and osteoconductive properties of mesenchymal stem cells and bone-relevant biomaterials that reflect bone-healing mechanisms. In this review, we summarize the current knowledge of bone-healing mechanisms focusing on the details that should be embodied in the development of vascularized BTE, and discuss promising strategies based on 3D-bioprinting technologies that efficiently coalesce the abovementioned main features in bone-healing systems, which comprehensively interact during the bone regeneration processes.

The pathogenesis of primary acquired nasolacrimal duct obstruction (PANDO) remains unclear, with several factors implicated, including anatomical structures, hormones, and tear components. This study explored tear proteins to better understand PANDO etiology by comparing protein expression in tears from patients with PANDO and healthy controls. Tear samples were collected from 22 patients with PANDO (mucous and membranous types) and 8 controls using Weck-Cel sponges. Protein analysis was conducted using LC-MS/MS to identify and quantify tear proteins. Female patients with PANDO had higher numbers of differentially expressed proteins (DEPs) compared with males. Certain DEPs associated with inflammatory pathways or the lacrimal duct epithelium, including SERPINB1, SERPINA3, CTSG, SLPI, and EZR, were identified in male patients. Although this is a preliminary study, our results offer insights into the pathogenesis of PANDO, with potential to distinguish between mucous and membranous subtypes. The potential biomarkers identified in this study could enhance early diagnosis and treatment, shedding light on inflammatory and immune processes in PANDO.