Osteoinductive micro-nano guided bone regeneration membrane for in situ bone defect repair.

BACKGROUND: Biomaterials used in bone tissue engineering must fulfill the requirements of osteoconduction, osteoinduction, and osseointegration. However, biomaterials with good osteoconductive properties face several challenges, including inadequate vascularization, limited osteoinduction and barrier ability, as well as the potential to trigger immune and inflammatory responses. Therefore, there is an urgent need to develop guided bone regeneration membranes as a crucial component of tissue engineering strategies for repairing bone defects. METHODS: The mZIF-8/PLA membrane was prepared using electrospinning technology and simulated body fluid external mineralization method. Its ability to induce biomimetic mineralization was evaluated through TEM, EDS, XRD, FT-IR, zeta potential, and wettability techniques. The biocompatibility, osteoinduction properties, and osteo-immunomodulatory effects of the mZIF-8/PLA membrane were comprehensively evaluated by examining cell behaviors of surface-seeded BMSCs and macrophages, as well as the regulation of cellular genes and protein levels using PCR and WB. In vivo, the mZIF-8/PLA membrane's potential to promote bone regeneration and angiogenesis was assessed through Micro-CT and immunohistochemical staining. RESULTS: The mineralized deposition enhances hydrophilicity and cell compatibility of mZIF-8/PLA membrane. mZIF-8/PLA membrane promotes up-regulation of osteogenesis and angiogenesis related factors in BMSCs. Moreover, it induces the polarization of macrophages towards the M2 phenotype and modulates the local immune microenvironment. After 4-weeks of implantation, the mZIF-8/PLA membrane successfully bridges critical bone defects and almost completely repairs the defect area after 12-weeks, while significantly improving the strength and vascularization of new bone. CONCLUSIONS: The mZIF-8/PLA membrane with dual osteoconductive and immunomodulatory abilities could pave new research paths for bone tissue engineering.

[Analysis of the complications following the periareolar reduction mammaplasty using polypropylene mesh as suspension device].

OBJECTIVE: To investigate the cause and the prophylactic measures for the complication following the periareolar reduction mammaplasty using polypropylene mesh as suspension device. METHODS: From Dec. 1999 to Dec. 2005, 78 patients who underwent periareolar reduction mammaplasty using polypropylene mesh as suspension device were analysed. Among them, 47 cases were followed-up for 6 months to 5 years, and their long-term effect was evaluated. RESULTS: Early after operation, complications included seroma (3 cases), infection (3 cases), delayed wound healing (3 cases), and paraesthesia of nipple-areolar complex (1 case). The 47 followed-up patients presented abnormal wave-like skin appearance in superior polar of breast (7 cases), palpable cord-like mammary content in peripheral region of breast (3 cases), widening of periareolar scar and secondary ptosis (2 cases) and paraesthesia of nipple-areolar complex (1 case). All other patients acquired good appearance and felt satisfactory. 2 patients could lactate after operation. 5 patients underwent mammary X-ray radiography after operation. No mesh shadow or calcification was revealed. CONCLUSIONS: Although polypropylene mesh is a good suspension device in reduction mammaplasty, the long-term complication is relatively high because of the hardness of the tissue. More soft tissue is necessary as alternative device for clinical application.

[3-Dimensional reconstruction of MRI in patients with polyacrylamide hydrogel injection for augmentation mammoplasty].

OBJECTIVE: To investigate the effective diagnostic method for the patients with polyacrylamide hydrogen injection for augmentation mammaplasty. METHODS: MRI scanning (layer thickness 1mm, t2 _ ps3d_ cor alignment) was performed on 23 patients with polyacrylamide hydrogen injection for augmentation mammaplasty. The data were imported into computer and processed. 3D reconstruction and analysis modules were run subsequently to do the volume reconstruction and surface reconstruction to obtain stereoscopic images of the gel and adjacent structures in virtual reality, and to calculate the volume of the hydrogel. RESULTS: Among the 23 patients (46 breasts), the injected hydrogel with integrity capsule existed in retromammary space with no malposition in 5 cases (10 breasts). The capsule was not integrally formed and hydrogel was separately distributed with irregular edge in 6 patients (12 breasts). The pectoris major space, subcutaneous and gland invasion was found in 11 patients (22 breasts). Small amount of hydrogel sparsely distributed in mammary gland and degenerative muscular tissue in 1 patient (2 breasts) who had received extracting surgery before. The volume of hydrogel ranged from 220.309 ml to 372.371 ml (mean: 306.328 ml) in 22 untreated patients (44 breasts). CONCLUSIONS: The volume and distribution of hydrogel can be known clearly by 3D MRI reconstruction technique. This feasible technique is helpful in removing the hydrogel completely.

[Analysis and treatment of complications induced by polyacrylamide hydrogel injection].

OBJECTIVE: To explore the reasons for the complications of polyacrylamide hydrogel injection. METHODS: 39 patients were included in this study, who had complications after polyacrylamide hydrogel injection in the breasts, nose, temproal area or depressed locus. The clinical manifestations of the complications were analyzed. RESULTS: Postoperative infection occurred in 5 cases, induration in 23, pain in 25, ulceration of the puncture points in 9, displacement in 6, galactostasis in 1, skin necrosis in 1, breast deformation in 3, bilateral asymmetry in 4, aseptic inflammation in 10, and skin-acne-like changes on the face in 4. CONCLUSION: Some complications were caused mainly by incorrect manipulation and others were relative to the injected material. The applications of polyacrylamide hydrogel as a clinical implant material need further investigations. Polyacrylamide hydrogel injection should be cautiously used.