Osteoarthritic human chondrocytes proliferate in 3D co‐culture with mesenchymal stem cells in suspension bioreactors

Osteoarthritis (OA) is a painful disease, characterized by progressive surface erosion of articular cartilage. The use of human articular chondrocytes (hACs) sourced from OA patients has been proposed as a potential therapy for cartilage repair, but this approach is limited by the lack of scalable methods to produce clinically relevant quantities of cartilage‐generating cells. Previous studies in static culture have shown that hACs co‐cultured with human mesenchymal stem cells (hMSCs) as 3D pellets can upregulate proliferation and generate neocartilage with enhanced functional matrix formation relative to that produced from either cell type alone. However, because static culture flasks are not readily amenable to scale up, scalable suspension bioreactors were investigated to determine if they could support the co‐culture of hMSCs and OA hACs under serum‐free conditions to facilitate clinical translation of this approach. When hACs and hMSCs (1:3 ratio) were inoculated at 20,000 cells/ml into 125‐ml suspension bioreactors and fed weekly, they spontaneously formed 3D aggregates and proliferated, resulting in a 4.75‐fold increase over 16 days. Whereas the apparent growth rate was lower than that achieved during co‐culture as a 2D monolayer in static culture flasks, bioreactor co‐culture as 3D aggregates resulted in a significantly lower collagen I to II mRNA expression ratio and more than double the glycosaminoglycan/DNA content (5.8 vs. 2.5 μg/μg). The proliferation of hMSCs and hACs as 3D aggregates in serum‐free suspension culture demonstrates that scalable bioreactors represent an accessible platform capable of supporting the generation of clinical quantities of cells for use in cell‐based cartilage repair.     

Inhibition of growth and induction of apoptosis by all-trans retinoic acid in lymphoid cell lines transfected with the PML/RARα fusion gene

The interaction of an exogenous PML/RARα fusion gene associated with acute promyelocytic leukaemia, with all- trans retinoic acid (ATRA) was examined in two lymphoid cell lines. L1210 and MOLT-4 cells were transfected with PML/RARα cDNA in the expression vector pGD and stable transformants (L1210 PML/RAR α and MOLT-4 PML/RAR α) were selected with G418. ATRA inhibited the growth of these stable transformants, as assessed by [³H]thymidine incorporation, in a dose-dependent manner, but had no effect on the growth of control cells stably transformed with neomycin resistant gene alone. ATRA also induced apoptosis, as assessed by fragmentation of genomic DNA, in L1210 PML/RAR α and MOLT-4 PML/RAR α cells but not in control cells. The exogenous PML/RARα fusion gene therefore probably mediates the effects of ATRA on cell growth and apoptosis in these cell lines.     

Innate lymphocytes: pathogenesis and therapeutic targets of liver diseases and cancer

The liver is a lymphoid organ with unique immunological properties, particularly, its predominant innate immune system. The balance between immune tolerance and immune activity is critical to liver physiological functions and is responsible for the sensitivity of this organ to numerous diseases, including hepatotropic virus infection, alcoholic liver disease, nonalcoholic fatty liver disease, autoimmune liver disease, and liver cancer, which are major health problems globally. In the past decade, with the discovery of liver-resident natural killer cells, the importance of innate lymphocytes with tissue residency has gradually become the focus of research. In this review, we address the current knowledge regarding hepatic innate lymphocytes with unique characteristics, including NK cells, ILC1/2/3s, NKT cells, γδ T cells, and MAIT cells, and their potential roles in liver homeostasis maintenance and the progression of liver diseases and cancer. A better understanding of the immunopathogenesis of hepatic innate lymphocytes will be helpful for proposing effective treatments for liver diseases and cancer.     

A Case Report of Non-Hodgkin Low-grade B-cell Mucosa-associated Lymphoid Tissue Lymphoma Presenting as a Suspected Endodontic Lesion

Extranodal mucosa-associated lymphoid tissue lymphoma is a rare oral disease. This case report describes a 71-year-old woman who presented for endodontic evaluation and treatment for swelling on the right posterior palatal. The case details the evaluation and diagnostic processes and treatment course. The case report draws attention to the importance of performing a biopsy, having proper sampling, and the additional steps sometimes required to arrive at a definitive diagnosis. This case report is the first to document a definitive low-grade B-cell mucosa-associated lymphoid tissue lymphoma mimicking endodontic pathology. The case shows the importance of proper examination, clinical imaging, and pathologic testing to arrive at a definitive diagnosis. It highlights that collaboration with other medical and dental specialties is essential for appropriate diagnosis and treatment and describes the “buttonhole” diagnostic strategy.     

Long-term Success and Survival of Endodontic Microsurgery

IntroductionHealed rates of endodontic microsurgery (EMS) may decrease over time, but research on the long-term outcomes is scarce. The aims of this retrospective cohort study were to evaluate the 5- to 9-year healed and survival rates of EMS, to identify associations between prognostic factors and healing status, and to compare the short-term (1- to 2-year) with long-term (5- to 9-year) outcomes.MethodsOne hundred fifty-one eligible patients (166 teeth) who underwent EMS in 2007–2010 were invited for a follow-up examination. Eighty-three patients (94 teeth) participated in the study. Survival status and reasons for extraction of all teeth were determined, and survival rates were calculated by Kaplan-Meier analyses. Outcomes were determined on the basis of clinical and radiographic findings and associated with potential prognostic variables via multivariate Cox regression analyses.ResultsThirty-two teeth were extracted: 6 because of endodontic failure, 20 for unrelated reasons, and 6 for unknown reasons. Outcomes were categorized as healed and not healed. Multivariate analysis revealed that adjusted hazard ratio for failure was 5.95 times higher (95% confidence interval, 1.54–22.91) for teeth treated with intermediate restorative material than with mineral trioxide aggregate and 3.38 times higher (95% confidence interval, 1.05–10.9) for teeth with no known history of nonsurgical retreatment. Teeth classified as healed in the 1- to 2-year review mostly remained healed at 5- to 9-year review (45/48 teeth); those with uncertain healing had varied outcomes at long-term review.ConclusionsEMS results in high long-term healed (78.3%, 72/92 teeth) and survival (95.2%) rates. Root-end filling material and nonsurgical retreatment before EMS may influence the long-term outcome.