The repair of articular cartilage defects is still challenging in the fields of orthopedics and maxillofacial surgery due to the avascular structure of articular cartilage and the limited regenerative capacity of mature chondrocytes. To provide viable treatment options, tremendous efforts have been made to develop various chondrogenically-functionalized biomaterials for cartilage tissue engineering. Peptides that are derived from and mimic the functions of chondroconductive cartilage extracellular matrix and chondroinductive growth factors, represent a unique group of bioactive agents for chondrogenic functionalization. Since they can be chemically synthesized, peptides bear better reproducibility, more stable efficacy, higher modifiability and yielding efficiency in comparison with naturally derived biomaterials and recombinant growth factors. In this review, we summarize the current knowledge in the designs of the chondroinductive/chondroconductive peptides, the underlying molecular mechanisms and their-functionalized biomaterials for cartilage tissue engineering. We also systematically compare their in-vitro and in-vivo efficacies in inducing chondrogenesis. Our vision is to stimulate the development of novel peptides and their-functionalized biomaterials for cartilage tissue engineering.

Introduction A series of retrospectively recorded patients with cleft lip and palate was uniquely investigated to demonstrate and analyze the complications after cleft repairing operations in a selected Chinese population. Material and Methods From January 2005 to January 2012, a selected group of 2100 patients with cleft lip and/or palate who have complete records were chosen from a large sample in the units. Complete data were retrieved, including sex, age, clinical classification, surgical modality, complications, and follow-up results. The complications were classified into 2 categories: early and long-term complications. After surgery, most patients with cleft lip remained in the hospital for 7 days and cleft palate repairs for 10 days. A standard regimen of antibiotics was administered for 3 to 5 days clinically. Results Of the 2100 patients, there were 1360 males and 760 females who had congenital cleft deformity with complete clinical records in the department of oral and maxillofacial surgery. The age distribution was as follows: 1600 patients in the group of 3 months to 2 years, 320 patients in the group of 2 to 10 years, 130 patients in the group of 11 to 19 years, and 50 patients in the group of older than 20 years. As to the treatment modality, cleft lips were repaired by rotation advancement method with various minor modifications or Tennison modality. The cleft palates were closed using the von Langenbeck, Veau/Wardill/Kilner, or Furlow technique. The overall complication rate was 16.8% of the patients. Of the early complications, there were 6 cases of asphyxia, 17 cases of pyrexia, 5 cases of edema of the respiratory tract, 8 cases of upper respiratory tract infection, 6 cases of bronchiolitis, 7 cases of pneumonia, 9 cases of diarrhea and vomiting, 6 cases of hemorrhage, 5 patients of odontoptosis, 11 cases of erosion of the corner of mouth, 5 cases of drowsiness, 11 cases of incision dehiscence, 9 cases of wound infection, 6 cases of palatal dehiscence/fistula, 3 cases of nostril floor breakdown, 7 cases of conjunctivitis, as well as 3 cases of mortality. The long-term complications included 30 cases of secondary lip/nasal deformity, 10 cases of dehiscence of lip, 14 cases of palatal fistula/decencies, 18 cases of hearing problem/otitis media, 21 cases of poor ventilation/snoring, 66 cases of velopharyngeal incompetence, and 58 cases of voice disorder. Conclusions Complications after cleft surgery are unavoidable clinically. More attention should be paid to the etiologic factors to minimize the prevalence of complications. Mortality can be found in patients with cleft, which is a deadly complication. Problems of respiratory tract and hemorrhage should be emphasized and treated seriously.

Changes in oxygen concentration may influence various innate characteristics of stem cells. The effects of varying oxygen concentration on human periodontal ligament stem cells (HPDLSCs) has not been explored, particularly under hypoxia-related conditions. First, HPDLSCs were cultured from the periodontium of human teeth using the outgrowth method. STRO-1 and CD146 expression of HPDLSCs was investigated by flow cytometry. To detect the multilineage differentiation capacities of HPDLSCs, osteogenic-like and adipogenic-like states were induced in cells. Next, HPDLSCs (passage 3) were exposed to normal oxygen (21% O2) or hypoxia (2% O2) conditions for 7 days and cell proliferation was evaluated. After culture in osteogenic medium for 7 days, osteoblastic differentiation was evaluated by semi-quantitative reverse transcription-polymerase chain reaction analysis to detect 3 osteoblastic markers: core-binding factor a 1/runt-related transcription factor 2, osteocalcin, and osteopontin. In addition, each cell group was incubated with a hydroxyapatite/tricalcium phosphate carrier and transplanted subcutaneously into the back of immunocompromised mice to investigate transplantation differences in vivo. HPDLSCs were isolated, cultured, and successfully identified. After exposure of HPDLSCs to hypoxia for 7 days, the proliferation rate was increased and showed higher osteogenic differentiation potential compared to control cells. After 12 weeks of transplantation, hypoxia-treated HPDLSCs differentiated into osteoblast-like cells that formed bone-like structures. These results suggest that oxygen concentrations affect various aspects of HPDLSC physiology and that hypoxia enhances osteogenic differentiation both in vivo and in vitro. Oxygen concentration may be a critical parameter for HPDLSCs during expansion and differentiation.

Among C₂S-induced differentially expressed circRNAs, circ_1983 is involved in osteogenesisviacirc_1983–miR-6931–Gas7 ceRNA interaction-mediated Runx2 upregulation.