Despite the interaction between bone marrow mesenchymal stem cells (BMSCs) and macrophages has been found to play a critical role in repairing bone defects, it remains a challenge to develop a desirable tissue engineering scaffold for synchronous regulation of osteogenic differentiation and macrophage polarization. Herein, this study proposed a novel strategy to treat bone defects based on three-dimensional Gelatin Methacryloyl Inverted Colloidal Crystal (3D GelMA ICC) scaffold and an active 15-hydroxyprostaglandin dehydrogenase (15-PGDH) inhibitor SW033291. Specifically, the 3D GelMA ICC scaffolds were firstly prepared by colloidal templating method, which displayed good cell attachment and promoted intercellular interaction among macrophage and BMSCs due to its uniform pore interconnectivity. By combined use of SW033291, the release of Prostaglandin E2 (PGE2) from BMSCs on the GelMA ICC scaffold was significantly upregulated and macrophages M2 polarization was markedly increased. In turn, BMSCs proliferation and osteogenic differentiation was further enhanced by paracrine regulation of M2 macrophage, and thus finally caused more in vivo new bone formation by shaping up a pro-regenerative local immune microenvironment surrounding GelMA ICC scaffold. Our findings demonstrate the potential of 3D GelMA ICC scaffolds combined with SW033291 to become an effective tissue engineering strategy for bone regeneration.

Backgrounds: The primary controversy surrounding the treatment of anterior disc displacement (ADD) of temporomandibular joints (TMJ) stems from the unclear relationship between disc position and condylar adaptation. The long-term impact of varying disc position on condylar bone remodeling remains poorly understood. Methods: A randomized controlled clinical trial was conducted to evaluate the effects of different disc positions on condylar bone modeling/remodeling at baseline (T0) and after an 18-month follow-up (T1). Patients under 25 years of age diagnosed with TMJ ADD without reduction (ADDwoR) were enrolled and randomly allocated in a 1:1 ratio to either the disc displaced (DD) group or the disc reposited (DR) group. Participants in the DR group underwent arthroscopic disc repositioning surgery, whereas those in the DD group received no occlusal or surgical intervention. CT scans were obtained at T0 and T1, and three-dimensional condylar reconstructions were generated using Mimics 21.0 software. Seven anatomical points were defined on the condylar surface to represent distinct regions. The condylar volume and vertical height of 7 points were measured for the analysis. Results: This study included 60 patients with ADDwoR. At T1, the DR group demonstrated a significant increase in total condylar volume of 279.6 mm ³ per patient, compared to a slight 29.5 mm ³ increase in the DD group ( P < 0.0001). Differential height changes were observed between groups, particularly at the posterolateral and lateral condylar surfaces ( P < 0.05). Besides, anterolaterally displaced discs were associated with bone resorption at the posteromedial condyle, in contrast to anteromedially displaced discs at T0 ( P < 0.01). Conclusions: This study provides compelling evidence that ADDwoR restricts condylar bone growth in adolescents and young adults. Furthermore, disc position directly determines patterns of condylar bone modeling and remodeling in this population.

Background: Most of the current tracheotomy-related recommendations centers on indications, evaluations and post-treatment care, while on an educational standpoint, little knowledge of the pre-tracheal anatomies/variations can be found, which may play an important role in avoiding tracheotomy-related complications. This study aims to assess the anatomical relationship and age-related variability of the anatomies in the pre-tracheal space in older adult patients with head and neck cancers and to guide tracheotomy with clinical evidence for either planned or improvised procedures. Methods: From January 2019 to February 2022, hospitalized head and neck cancer patients aged over 65 years (127 cases) and under 65 years (74 cases) were enrolled in this study as the observation and the control groups, respectively. All these patients received contrast-enhanced computed tomography (CECT) scans, ablative operations and tracheotomies for primary head and neck cancers. The radiographic reconstructions of vascular morphologies were compared, focusing on three target vessels: anterior jugular veins (AJVs), innominate arteries (IAs) and inferior thyroid vascular plexus (ITVPs). The upper locations of the isthmus, and the largest diameters of thyroid glands were compared as well. In addition, surgical exposure of those vessels was recorded during tracheostomies to verify these radiologic findings. The tracheotomy procedure-related complications were also compared. Results: A total number of 201 patients (115 males and 86 females) were identified in this study. The mean age of the older adult group reached 72.0 years (range, 65–87 years), most (86/127, 67.7%) were with oral cancer. The ratio of single-branch type AJVs in the older-adult group (15/126, 11.9%) was higher than that in the non-older adult counterpart (6/73, 8.2%), though no statistical difference was found (P=0.701). Radiologically speaking, the IAs were mainly categorized as the low-bifurcation (104/201, 51.7%), high-bifurcation (37/201, 18.4%), high-platform (27/201, 13.4%), low-platform (30/201, 14.9%), and variant types (3/201, 1.5%). Age-related changes of IA types were found between the older and the non-older adult groups (P<0.01), especially for the platform IAs types, which might interfere with intraoperative tracheal exposure. This phenomenon was also closely related to our intraoperative tracheotomy findings (r_n=0.59, P<0.01). Besides, for the ITVPs, the common-trunk subtypes were mostly found in the older adult group (50/125, 40%). Conclusions: Considering the age-related changes, the evaluation of the pre-tracheal anatomies based on radiographic evidence can facilitate safer tracheotomies in older adult patients. Besides, educational implications for impromptu tracheotomies may also be drawn with knowledge of these variable anatomies.