Establishment of a myelinating co-culture system with a motor neuron-like cell line NSC-34 and an adult rat Schwann cell line IFRS1.

Co-culture models of neurons and Schwann cells have been utilized for the study of myelination and demyelination in the peripheral nervous system; in most of the previous studies, however, these cells were obtained by primary culture with embryonic or neonatal animals. A spontaneously immortalized Schwann cell line IFRS1 from long-term cultures of adult Fischer rat peripheral nerves has been shown to retain fundamental ability to myelinate neurites in co-cultures with adult rat dorsal root ganglion neurons and nerve growth factor-primed PC12 cells. Our current investigation focuses on the establishment of stable co-culture system with IFRS1 cells and NSC-34 motor neuron-like cells. NSC-34 cells were seeded at a low density (2 × 103/cm2) and maintained for 5-7 days in serum-containing medium supplemented with non-essential amino acids and brain-derived neurotrophic factor (BDNF; 10 ng/mL). Upon observation of neurite outgrowth under a phase-contrast microscope, the NSC-34 cells were exposed to an anti-mitotic agent mitomycin C (1 µg/mL) for 12-16 h, then co-cultured with IFRS1 cells (2 × 104/cm2), and maintained in serum-containing medium supplemented with ascorbic acid (50 µg/mL), BDNF (10 ng/mL), and ciliary neurotrophic factor (10 ng/mL). Double immunofluorescence staining carried out at day 28 of the co-culture showed myelin protein (P0 or PMP22)-immunoreactive IFRS1 cells surrounding the ßIII tubulin-immunoreactive neurites. This co-culture system can be a beneficial tool to study the pathogenesis of motor neuron diseases (e.g., amyotrophic lateral sclerosis, Charcot-Marie-Tooth diseases, and immune-mediated demyelinating neuropathies) and novel therapeutic approaches against them.

The number of microvascular complications is associated with an increased risk for severity of periodontitis in type 2 diabetes patients: Results of a multicenter hospital-based cross-sectional study.

AIMS/INTRODUCTION: To explore the relationships between periodontitis and microvascular complications as well as glycemic control in type 2 diabetes patients. MATERIALS AND METHODS: This multicenter, hospital-based, cross-sectional study included 620 patients with type 2 diabetes. We compared the prevalence and severity of periodontitis between patients with ≥1 microvascular complication and those without microvascular complications. We also compared the prevalence and severity of periodontitis among patients with different degrees of glycemic control. RESULTS: After adjusting for confounding factors, multiple logistic regression analysis showed that the severity of periodontitis was significantly associated with the number of microvascular complications (odds ratio 1.3, 95% confidence interval 1.1-1.6), glycated hemoglobin ≥8.0% (64 mmol/mol; odds ratio 1.6; 95% confidence interval 1.1-2.3), and older age (≥50 years; odds ratio 1.7; 95% confidence interval 1.1-2.6). However, the prevalence of periodontitis was not significantly associated with the number of microvascular complications, but was associated with male sex, high glycated hemoglobin (≥8.0% [64 mmol/mol]), older age (≥40 years), longer duration of diabetes (≥15 years) and fewer teeth (≤25). Furthermore, propensity score matching for age, sex, diabetes duration and glycated hemoglobin showed that the incidence of severe periodontitis was significantly higher among patients with microvascular complications than among those without microvascular complications (P < 0.05). CONCLUSIONS: The number of microvascular complications is a risk factor for more severe periodontitis in patients with type 2 diabetes, whereas poor glycemic control is a risk factor for increased prevalence and severity of periodontitis.