Stiffness-tuned and ROS-sensitive hydrogel incorporating complement C5a receptor antagonist modulates antibacterial activity of macrophages for periodontitis treatment

Periodontitis is admittedly a microbe-driven intractable infectious disease,in which Porphyromonas gingivalis(Pg)plays a keystone role.Pg can selectively impair the antimicrobial responses of periodontal resident macrophages including their phagocytic and bactericidal activity without interfering their proinflammatory activity,which leads to microflora disturbance,destructive periodontal inflammation and alveolar bone loss eventually.Here,an injectable ROS-sensitive hydrogel is developed for releasing active bone marrow-derived macrophages(named ex-situ macrophages hereafter)and a complement C5a receptor antagonist(C5A)to the gingival crevice.Through appropriately tuning the hydrogel stiffness,the phagocytic activity of these macrophages is greatly enhanced,reaching an optimal performance at the elastic modulus of 106 kPa.Meanwhile,C5A avoids undesired C5a receptor activation by Pg to ensure the bacterial killing activity of both the ex-situ and in-situ macrophages.Besides,the ROS-sensitive hydrogels show another distinct feature of decreasing the ROS level in periodontal niche,which contributes to the alleviated periodontal inflammation and attenuated bone loss as well.This study highlights the potential of utilizing hydrogels with tailored biomechanical properties to remodel the functions of therapeutic cells,which is expected to find wide applications even beyond periodontitis treatment.

儿童错[牙合]畸形早期矫治的研究进展

儿童错[牙合]畸形的早期矫治是当今正畸乃至整个口腔医学领域中的热门话题,同时也颇具争议。大部分的口腔正畸临床医生提倡对儿童错[牙合]畸形进行早期干预,及时去除影响口颌系统发育的不良因素,阻断颌面部异常的生长趋势,以缩短后续正畸时间和降低治疗难度。然而,也有部分学者认为早期矫治收益不大。本文从错[牙合]畸形的病因出发,通过回顾文献并结合临床经验,分析各类错[牙合]畸形的特点,讨论各类错[牙合]早期矫治的必要性与理想矫治时机,并就早期矫治的经典研究与最新研究进展进行简要概述。