RESUMO
Oral mucositis (OM) is a severe complication of cancer therapies caused by off-target cytotoxicity. Palifermin, which is recombinant human keratinocyte growth factor (KGF), is currently the only mitigating treatment available to a subset of OM patients. This study used a previously established model of oral mucositis on a chip (OM-OC) comprised of a confluent human gingival keratinocytes (GIE) layer attached to a basement membrane-lined subepithelial layer consisting of human gingival fibroblasts (HGF) and human dermal microvascular endothelial cells (HMEC) on a stable collagen I gel. Cisplatin, radiation, and combined treatments are followed by a recovery period in the OM-OC to determine possible cellular and molecular mechanisms of OM under effects of KGF. Cancer treatments affected the keratinocyte layer, causing death and epithelial barrier loss. Both keratinocytes and subepithelial cells died rapidly, as evidenced by propidium iodide staining. In response to radiation exposure, cell death occurred in the apical epithelial layer, predominantly, within 24h. Cisplatin exposure predominantly promoted death of basal epithelial cells within 32-36h. Presence of KGF in OM-OC protected tissues from damage caused by cancer treatments in a dose-dependent manner, being more effective at 10 ng/mL. As verified by F-actin staining and the Alamar Blue assay, KGF contributed to epithelial survival and induced proliferation of GIE and HGF as well as HMEC within 120h. When the expression of eighty inflammatory cytokines is evaluated at OM induction (Day 12) and resolution (Day 18) stages in OM-OC, some cytokines are identified as potential novel therapeutic targets. In comparison with chemoradiation exposure, KGF treatment showed a trend to decrease IL-8 and TNF-a expression at Day 12 and 18, and TGF-ß1 at Day 18 in OM-OC. Taken together, these findings support the utility of OM-OC as a platform to model epithelial damage and evaluate molecular mechanisms following OM treatment.
RESUMO
BACKGROUND: Neurologic impairments are a significant concern for survivors after pediatric cardiac surgery with cardiopulmonary bypass (CPB). We have previously shown that mesenchymal stromal cell (MSC) delivery through CPB has the potential to mitigate the effects of CPB on neural stem/progenitor cells. This study assessed the dose effects of MSCs. METHODS: Piglets (n = 20) were randomly assigned to 1 of 4 groups: control, CPB, or CPB followed by MSC administration with low and high doses (10 × 106 and 100 × 106 cells per kilogram). We assessed acute dose effect on cell distribution, multiorgan functions, systemic inflammation, microglia activation, and neural stem/progenitor cell activities. RESULTS: By magnetic resonance imaging, approximately 10 times more MSCs were detected within the entire brain after high-dose delivery than after low-dose delivery. No adverse events affecting hemodynamics, various biomarkers, and neuroimaging were detected after high-dose MSC delivery. High-dose MSCs significantly increased circulating levels of interleukin 4 after CPB. Both MSC groups normalized microglia activation after CPB, demonstrating MSC-induced reduction in cerebral inflammation. There was a significant increase in neuroblasts in the subventricular zone in both treatment groups. The thickness of the most active neurogenic area within the subventricular zone was significantly increased after high-dose treatment compared with CPB and low-dose MSCs, suggesting dose-dependent effects on the neurogenic niche. CONCLUSIONS: MSC delivery through CPB is feasible up to 100 × 106 cells per kilogram. MSC treatment during cardiac surgery has the potential to reduce systemic and cerebral inflammation and to modulate responses of an active neurogenic niche to CPB. Further investigation is necessary to assess the long-term effects and to develop a more complete dose-response curve.