Oral cavity-derived stem cells and preclinical models of jaw-bone defects for bone tissue engineering.

BACKGROUND: Jaw-bone defects caused by various diseases lead to aesthetic and functional complications, which can seriously affect the life quality of patients. Current treatments cannot fully meet the needs of reconstruction of jaw-bone defects. Thus, the research and application of bone tissue engineering are a "hot topic." As seed cells for engineering of jaw-bone tissue, oral cavity-derived stem cells have been explored and used widely. Models of jaw-bone defect are excellent tools for the study of bone defect repair in vivo. Different types of bone defect repair require different stem cells and bone defect models. This review aimed to better understand the research status of oral and maxillofacial bone regeneration. MAIN TEXT: Data were gathered from PubMed searches and references from relevant studies using the search phrases "bone" AND ("PDLSC" OR "DPSC" OR "SCAP" OR "GMSC" OR "SHED" OR "DFSC" OR "ABMSC" OR "TGPC"); ("jaw" OR "alveolar") AND "bone defect." We screened studies that focus on "bone formation of oral cavity-derived stem cells" and "jaw bone defect models," and reviewed the advantages and disadvantages of oral cavity-derived stem cells and preclinical model of jaw-bone defect models. CONCLUSION: The type of cell and animal model should be selected according to the specific research purpose and disease type. This review can provide a foundation for the selection of oral cavity-derived stem cells and defect models in tissue engineering of the jaw bone.

Phase I study of postoperative radiotherapy concurrent with S-1 in patients with gastric cancer.

Postoperative chemoradiotherapy (CRT) with concurrent 5-fluorouracil is the standard care for gastric cancer patients after curative surgery. The previous studies revealed that the subgroup of patients with high recurrence risk would benefit most from adjuvant CRT. S-1, a novel oral fluorouracil, has showed very effective in metastatic gastric cancer and became the standard option for gastric cancer with D2 dissection. The safety and dosage of S-1 combined with postoperative radiotherapy have not yet been evaluated. This study is to determine the maximum tolerate dose (MTD) and dose-limiting toxicity (DLT) of S-1 given concurrently with postoperative high-dose radiotherapy in gastric cancer. Patients with more advanced stage (pT4 and/or pN+) after R0 resection were recruited. Eligible patients received one cycle standard SOX (S-1 plus oxaliplatin) chemotherapy, then S-1 monotherapy with concurrent radiotherapy for 6 weeks, followed by additional three cycles of SOX. During the concurrent CRT, S-1 was administered on every radiotherapy treatment day according to a predefined dose-escalation schedule. Radiotherapy (3D-RT or IMRT) was given to a total dose of 50.4 Gy in 28 fractions. DLT was defined as grade 3 or 4 hematologic and non-hematologic toxicity. From March 2011 to October 2012, 21 patients were enrolled at five dose levels: 40 (n = 3), 50 (n = 3), 60 (n = 6), 70 (n = 6) and 80 mg/m(2)/day (n = 3). D2-dissection was performed in 18 patients (85.7 %) and 15 patients (71.4 %) had stage III disease. The most common dose-related toxicity was anorexia, nausea and vomiting, fatigue and leucopenia. DLT was occurred in one patient at 60 mg/m(2)/day (grade 3 fatigue), one patient at 70 mg/m(2)/day (grade 3 vomiting and anorexia), two patients at 80 mg/m(2)/day (one with grade 3 vomiting and anorexia; another with grade 3 febrile leucopenia). Four patients did not complete CRT as planned. Overall, this phase I study demonstrated that postoperative CRT with daily S-1 was feasible in gastric cancer and the MTD of S-1 concurrent with radiotherapy was 70 mg/m(2)/day. This S-1-based postoperative CRT will be investigated in a multicenter phase III study in West China.