Olfactory ensheathing cells from the nasal mucosa and olfactory bulb have distinct membrane properties

The Anti-inflammation Property of Olfactory Ensheathing Cells in Neural Regeneration After Spinal Cord Injury

Neural regeneration has troubled investigators worldwide in the past decades. Currently, cell transplantation emerged as a breakthrough targeted therapy for spinal cord injury (SCI) in the neurotrauma field, which provides a promising strategy in neural regeneration. Olfactory ensheathing cells (OECs), a specialized type of glial cells, is considered as the excellent candidate due to its unique variable and intrinsic regeneration-supportive properties. In fact, OECs could support olfactory receptor neuron turnover and axonal extension, which is essential to maintain the function of olfactory nervous system. Hitherto, an increasing number of literatures demonstrate that transplantation of OECs exerts vital roles in neural regeneration and functional recovery after neural injury, including central and peripheral nervous system. It is common knowledge that the deteriorating microenvironment (ischemia, hypoxia, scar, acute and chronic inflammation, etc.) resulting from injured nervous system is adverse for neural regeneration. Interestingly, recent studies indicated that OECs could promote neural repair through improvement of the disastrous microenvironments, especially to the overwhelmed inflammatory responses. Although OECs possess unusual advantages over other cells for neural repair, particularly in SCI, the mechanisms of OEC-mediated neural repair are still controversial with regard to anti-inflammation. Therefore, it is significant to summarize the anti-inflammation property of OECs, which is helpful to understand the biological characteristics of OECs and drive future studies. Here, we mainly focus on the anti-inflammatory role of OECs to make systematic review and discuss OEC-based therapy for CNS injury.

Gene and protein expression profiles of olfactory ensheathing cells from olfactory bulb versus olfactory mucosa

Olfactory ensheathing cells (OECs) from the olfactory bulb (OB) and the olfactory mucosa (OM) have the capacity to repair nerve injury. However, the difference in the therapeutic effect between OB-derived OECs and OM-derived OECs remains unclear. In this study, we extracted OECs from OB and OM and compared the gene and protein expression profiles of the cells using transcriptomics and non-quantitative proteomics techniques. The results revealed that both OB-derived OECs and OM-derived OECs highly expressed genes and proteins that regulate cell growth, proliferation, apoptosis and vascular endothelial cell regeneration. The differentially expressed genes and proteins of OB-derived OECs play a key role in regulation of nerve regeneration and axon regeneration and extension, transmission of nerve impulses and response to axon injury. The differentially expressed genes and proteins of OM-derived OECs mainly participate in the positive regulation of inflammatory response, defense response, cytokine binding, cell migration and wound healing. These findings suggest that differentially expressed genes and proteins may explain why OB-derived OECs and OM-derived OECs exhibit different therapeutic roles. This study was approved by the Animal Ethics Committee of the General Hospital of Ningxia Medical University (approval No. 2017-073) on February 13, 2017.

Olfactory and taste dysfunction among mild-to-moderate symptomatic COVID-19 positive health care workers: An international survey

OBJECTIVES

To determine the prevalence of olfactory and taste dysfunction (OD; TD) among COVID-19 positive health care workers (HCWs), their associated risk factors and prognosis.

METHODS

Between May and June 2020, a longitudinal multicenter study was conducted on symptomatic COVID-19 PCR confirmed HCWs (COVID-19 positive) in London and Padua.

RESULTS

Hundred and fourteen COVID-19 positive HCWs were surveyed with a response rate of 70.6% over a median follow-up period of 52 days. UK prevalence of OD and TD was 73.1% and 69.2%, respectively. There was a male to female ratio of 1:3 with 81.6% being white, 43.7% being nurses/health care assistants (HCAs), and 39.3% being doctors. In addition, 53.2% of them worked on COVID-19 wards. Complete recovery was reported in 31.8% for OD and 47.1% for TD with a 52 days follow-up. The job role of doctors and nurses negatively influenced smell (P = .04 and P = .02) and taste recovery (P = .02 and P = .01). Ethnicity (being white) showed to positively influence only taste recovery (P = .04). Sex (being female) negatively influenced OD and TD recovery only in Paduan HCWs (P = .02 and P = .011, respectively). Working on a COVID-19 ward did not influence prognosis.

CONCLUSIONS

The prevalence of OD and TD was considerably higher in HCWs. The prognosis for OD and TD recovery was worse for nurses/HCAs and doctors but working on a COVID-19 ward did not influence prognosis. Sixty-eight percent of surveyed HCWs at 52 days continued to experience OD or TD requiring additional future medical management capacity.

LEVEL OF EVIDENCE

4.

Divergent membrane properties of mouse cochlear glial cells around hearing onset

Spiral ganglion neurons (SGNs) are the primary afferent neurons of the auditory system, and together with their attendant glia, form the auditory nerve. Within the cochlea, satellite glial cells (SGCs) encapsulate the cell body of SGNs, whereas Schwann cells (SCs) wrap their peripherally- and centrally-directed neurites. Despite their likely importance in auditory nerve function and homeostasis, the physiological properties of auditory glial cells have evaded description. Here, we characterized the voltage-activated membrane currents of glial cells from the mouse cochlea. We identified a prominent weak inwardly rectifying current in SGCs within cochlear slice preparations (postnatal day P5-P6), which was also present in presumptive SGCs within dissociated cultures prepared from the cochleae of hearing mice (P14-P15). Pharmacological block by Ba²⁺ and desipramine suggested that channels belonging to the Kir4 family mediated the weak inwardly rectifying current, and post hoc immunofluorescence implicated the involvement of Kir4.1 subunits. Additional electrophysiological profiles were identified for glial cells within dissociated cultures, suggesting that glial subtypes may have specific membrane properties to support distinct physiological roles. Immunofluorescence using fixed cochlear sections revealed that although Kir4.1 is restricted to SGCs after the onset of hearing, these channels are more widely distributed within the glial population earlier in postnatal development (i.e., within both SGCs and SCs). The decrease in Kir4.1 immunofluorescence during SC maturation was coincident with a reduction of Sox2 expression and advancing neurite myelination. The data suggest a diversification of glial properties occurs in preparation for sound-driven activity in the auditory nerve.

Cell therapy assisted autotransplantation of olfactory tract into the optic nerve: A potential treatment for optic neuropathy

Optic neuropathy is an invaliding pathology with diverse clinical manifestation and varying causes. Current understanding of etiopathological aspects of optical neuropathy does not provide an effective treatment protocol. In this article we discuss existing treatment methods, and their effectiveness, evaluated depending on disease etiology. The olfactory tract is a source of olfactory ensheating cells, whose unique properties can have treatment potential in correction of nerve degeneration. Transplantation of an olfactory tract graft into the damaged optic nerve is a technically achievable intervention, though anatomical limitations exist in the proposed surgical access. Optic nerve defects can also be potentially treated with axon growth stimulating therapy (Zymosan and CTP-cAMP). Optic neuropathy can be potentially cured by autotransplantation of a portion of the olfactory tract. Neuroanatomical and histomorphological aspects of olfactory tract autotransplantation into the damaged optic nerve are provided. Feasibility, technical and anatomical features, potential setbacks and limitations are discussed. Anatomical limitations exist, but with current neurosurgical technology can be overcome. Regenerative potential of olfactory tract glial cells plays an important role in nerve restoration and can play a crucial role in further understanding of nerve degeneration treatment.