Complications of cochlear implants: a MAUDE database study.

OBJECTIVE: A retrospective cross-sectional analysis was conducted of the US Food and Drug Administration's MAUDE (Manufacturer and User Facility Device Experience) database, to evaluate the complication profile of cochlear implantation according to manufacturer. METHODS: A review of the MAUDE database was conducted from 1 January 2010 to 31 December 2020. Complications, including infection, extrusion, facial nerve stimulation, meningitis and cerebrospinal fluid leak, were identified using key word searches. The categorised data were analysed using a chi-square test to determine a difference in global complication incidence between three major cochlear implant manufacturers: manufacturer A (Cochlear Limited), manufacturer B (Med-El) and manufacturer C (Advanced Bionics). RESULTS: A total of 31 857 adverse events were analysed. Implants of manufacturer C were associated with a statistically higher rate of infection (0.97 per cent), cerebrospinal fluid leak (0.07 per cent), extrusion (0.44 per cent) and facial nerve stimulation (0.11 per cent). Implants of manufacturer B were associated with a statistically higher rate of meningitis (0.07 per cent). CONCLUSION: Consideration of patient risk factors along with cochlear implant manufacturers can heighten awareness of cochlear implant complications pre-operatively, intra-operatively and post-operatively.

Lysosomal dysfunction in osteoarthritis and aged cartilage triggers apoptosis in chondrocytes through BAX mediated release of Cytochrome c.

OBJECTIVE: Lysosomes are the major catabolic organelle of the cell and regulate the macromolecular and organelle turnover and programmed cell death. Here, we investigated the lysosome dysfunction in cartilage and its role in chondrocytes apoptosis and the associated mechanism. DESIGN: Lysosomal acidification in Osteoarthritis (OA) and aged cartilage was determined by LysoSensor staining. Lysosomal function in chondrocytes was blocked by siRNA mediated depletion of Lysosomal Associated Membrane Protein 2 (LAMP2) or with lysosome inhibitors. Chondrocyte apoptosis was determined by LDH release, Caspase-3/7 activation, TUNEL and PI uptake assays. Loss of mitochondrial membrane potential (MMP/ΔΨM) and mitochondrial superoxide level was determined by JC-1 and MitoSOX staining, respectively. Colocalization of mitochondria with BCL2 associated X (BAX) and Cytochrome c was determined by immunostaining. Destabilization of medial meniscus (DMM) was performed to induce OA in mice. RESULTS: Lysosomal acidification was found to be significantly decreased in aged mouse and human and mouse OA cartilage which also showed increased chondrocyte apoptosis. Inhibition of lysosomal function resulted in increased oxidative stress, accumulation of dysfunctional mitochondria and apoptosis in chondrocytes in monolayer and in cartilage explant cultures. Depletion of LAMP2 expression or treatment of chondrocytes with lysosomal function inhibitors increased the expression and mitochondrial translocation of BAX leading to Cytochrome c release. Lysosomal dysfunction-induced apoptosis in chondrocytes was not blocked by antioxidants MitoTempo or Diphenyleneiodonium (DPI) but was abrogated by inhibiting BAX. CONCLUSION: Lysosomal dysfunction induce apoptosis in chondrocytes through BAX-mediated mitochondrial damage and release of Cytochrome c. Our data points to lysosomal function restoration and/or BAX inhibition in chondrocytes as a therapeutic approach for OA.