Endothelial Progenitor Cells inhibit jaw osteonecrosis in a rat model: A major adverse effect of bisphosphonate therapy.

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse effect of antiresorptive and antiangiogenic therapies. MRONJ is identified by chronic wounds in the oral mucosa associated with exposed necrotic bone. We hypothesized that zoledronic acid (ZOL) impairs keratinocyte and fibroblast function and reduces soft tissue vascularization; therefore, treating MRONJ with proangiogenic cells may benefit MRONJ patients. The effect of ZOL and dexamethasone (DEX) on gingival fibroblasts and keratinocytes was investigated. In-vitro, ZOL inhibited fibroblast and keratinocyte proliferation, delaying scratch healing. In-vivo, exposed bone was detected at tooth extraction sites, mainly in ZOL(+)/DEX(+) rats; and was associated with significantly decreased soft tissue vascularization, serum-VEGF, and tissue-VEGF. Local injection of early and late endothelial progenitor cells (EPCs) healed 13 of 14 MRONJ lesions compared with 2/7 lesions in the mesenchymal stem cells, and 2/6, in culture-medium group. The EPCs reduced necrotic bone area, increased serum and tissue VEGF levels. EPCs engraftment was minimal, suggesting their paracrine role in MRONJ healing. The EPC-conditioned medium improved scratch healing of keratinocytes and fibroblasts via VEGF pathway and elevated mRNA of VEGFA and collagen1A1. In conclusion, a novel MRONJ treatment with EPCs, increased vascularization and improved epithelial and fibroblast functions as well as cured the lesion.

Clinicopathologic analysis of verrucous hyperplasia, verrucous carcinoma and squamous cell carcinoma as part of the clinicopathologic spectrum of oral proliferative verrucous leukoplakia: A literature review and analysis.

OBJECTIVE: Proliferative verrucous leukoplakia is classified as a potentially malignant disorder because of its high rate of malignant transformation. PVL progresses in a series of clinical stages where the early stage represents multiple, multifocal leukoplakias with a high recurrence rate. The intermediate and late stages are clinically exophytic lesion, diagnosed microscopically as verrucous hyperplasia that often progresses into verrucous carcinoma and/or squamous cell carcinoma. There is no single histologic definition and the diagnosis is retrospective following observed progression of the disorder. The goal of the current study was to conduct a literature review and analysis of PVL in the later stages to gain further knowledge on their clinicopathologic features. DATA SOURCES: Medline's PubMed and Google Scholar were searched for adequately documented cases from 1985 to 2018. References of published articles were searched for additional cases. REVIEW METHODS: Overall, 57 manuscripts were analyzed. 35/57 manuscripts provided adequate data on the clinicopathologic features in the premalignant and malignant stages. RESULTS: Malignant transformation rate was 50% (average of 57 months). Gingiva, palate and buccal mucosa were the most common locations. Clinicopathologic features included; well differentiated carcinoma (78%), perineural invasion (3%), lymph node metastasis (4%); distant metastasis (0%), average duration of illness (65 months), DOD-dead of disease (44%). Moderate dysplasia, severe dysplasia and carcinoma in situ were exceptionally uncommon in the premalignant stages (0.8%). CONCLUSION: Prognostic factors such as perineural invasion, lymph node metastasis and distant metastasis were uncommon occurrences which may have practical implications on treatment. Further studies are needed to substantiate our findings.