Adhesive hydrogels in osteoarthritis: from design to application

Osteoarthritis (OA) is the most common type of degenerative joint disease which affects 7% of the global population and more than 500 million people worldwide. One research frontier is the development of hydrogels for OA treatment, which operate either as functional scaffolds of tissue engineering or as delivery vehicles of functional additives. Both approaches address the big challenge: establishing stable integration of such delivery systems or implants. Adhesive hydrogels provide possible solutions to this challenge. However, few studies have described the current advances in using adhesive hydrogel for OA treatment. This review summarizes the commonly used hydrogels with their adhesion mechanisms and components. Additionally, recognizing that OA is a complex disease involving different biological mechanisms, the bioactive therapeutic strategies are also presented. By presenting the adhesive hydrogels in an interdisciplinary way, including both the fields of chemistry and biology, this review will attempt to provide a comprehensive insight for designing novel bioadhesive systems for OA therapy.

[Clinical characteristics and diagnosis and treatment strategies of patients with severe traumatic aortic injury]

Objective: To investigate the clinical characteristics and diagnosis and treatment strategies of patients with severe traumatic aortic injury (TAI). Methods: A total of 25 patients with TAI, who hospitalized in our hospital between August 2005 to March 2021 and underwent thoracic aortic endovascular repair (TEVAR), were included in this retrospective study. According to the time from admission to TEVAR, the patients were divided into emergency TEVAR group (14 cases, TEVAR within 24 h of admission) and elective TEVAR group (11 cases, patients underwent surgery or fracture reduction and fixation first for serious injuries and then underwent TEVAR more than 24 h after admission). The general clinical data of patients, injury severity score (ISS), time from admission to intervention, total hospital stay, the proportion of closed chest drainage and the proportion of abdominal organ repair were obtained and compared. Clinical follow-up and 1-year postoperative aortic computed tomography angiography (CTA) were performed on the patients. Death, the occurrence of aortic adverse events and injury recovery were followed up and recorded. Results: The mean age of these 25 TAI patients was (41.4±14.4) years, 20 patients were males (80.0%). 21 patients (84.0%) had persistent chest and back pain, 17 (68.0%) had pleural effusion and 5 (20.0%) had mediastinal hematoma. The injury severity score (ISS) was significantly higher in the elective TEVAR group than in the emergency TEVAR group (24.9±14.4 vs. 35.5±9.3, P=0.044). The time from admission to intervention ((1.0±0.0) d vs. (3.4±0.9) d, P<0.001], the time from admission to TEVAR ((1.0±0.0) d vs. (11.5±13.8) d, P=0.030) and total hospital stay ((6.1±2.3) d vs. (26.8±7.7) d, P<0.001) were significantly longer in elective TEVAR group than in emergency TEVAR group. The proportion of thoracic closed drainage was significantly lower in the elective TEVAR group than in the emergency TEVAR group (9 (64.3%) vs. 2 (18.2%), P=0.042). The proportion of abdominal organ repair was significantly higher than in the emergency TEVAR group (0 vs. 4 (36.4%), P=0.026). All of 25 patients were discharged alive and followed up for (84.0±30.5) months. All patients survived and completed 1-year postoperation CTA. There were no aortic adverse events occurred, and no complications after surgery, and the fractures and organ injuries healed well. Conclusions: The clinical characteristics of severe TAI are acute multi-injuries combined with persistent chest and/or back pain, pleural effusion, and mediastinal hematoma. Timely diagnosis and treatment are important factors for the outcome. The treatment strategy for multi-injuries should give priority to dealing with life-threatening injuries. TEVAR is the primary treatment strategy for severe TAI and is related to satisfactory outcomes.

Quercetin and daidzein β-apo-14'-carotenoic acid esters as membrane antioxidants

Esterification by β-apo-14'-carotenoic acid was found to have opposite effects on antioxidant activity of quercetin (at B4', B3' hydroxyl) as of daidzein (at A7 hydroxyl) in phosphatidylcholine liposomes. The daidzein ester had increased activity, while quercetin had a significant decreased activity. Quantum mechanical calculations using density function theory (DFT) indicate a modest decrease in bond dissociation enthalpy, BDE, for (weakest) hydrogen-oxygen phenolic bond in daidzein from 368.4 kJ · mol(- 1) to 367.7 kJ · mol(- 1) compared to a significant increase in quercetin from 329.5 kJ · mol(- 1) to 356.6 kJ · mol(- 1) upon derivatization. These opposite changes in tendency for hydrogen atom transfer from phenolic groups to lipid radicals combined with an increase in A-to-B dihedral angle from 0.0° to 36.4° and in dipole moment from 0.40 D to 6.01 D for quercetin upon derivatization, while less significant for daidzein (36.4°-36.7° and 3.26 D-7.87 D, respectively), together provide a rationale for the opposite effect of esterification on antioxidation.

Chain length effects in isoflavonoid daidzein alkoxy derivatives as antioxidants: a quantum mechanical approach

Daidzein, an isoflavonoid with known prooxidative effects in heterogeneous lipid/water systems, changes to an antioxidant for 7-n-alkoxy derivatives of daidzein. For an alkyl length increasing from 4 to 8, 12, and 16 carbons, the oxidation potential decreases gradually from 1.09 V (vs NHE) for daidzein (D) to 0.94 V for D16 in tetrahydrofuran as determined by cyclic voltammetry at 25 °C. The prooxidative effects transform into antioxidative effects from D8 with a maximal effect for D12 for aqueous phase initiation of lipid oxidation in liposomes despite a gradual decrease in Trolox equivalent antioxidant capacity (TEAC) with increasing alkyl chain length. Quantum mechanical calculations using density functional theory (DFT) showed that the bond dissociation energy of the O-H bond of the 4'-phenol is constant along the homologue series in contrast to Δμ, the change in dipole moment upon hydrogen atom donation, which increases for increasing chain length. The frontier orbital energy gap goes through a maximum for D12. The change in the A-to-B dihedral angle upon hydrogen atom donation further shows a maximum for D12 of 6.45°. The importance of these microscopic properties for antioxidative activity was confirmed by a change in liposome fluorescence anisotropy using a fluorescent probe showing maximal penetration into the lipid bilayer for D12 along the homologue series.