A microscope-assisted endoscopic transcanal transpromontorial approach for vestibular schwannoma resection: a preliminary report.

OBJECTIVE: To evaluate the feasibility of a microscope-assisted endoscopic transcanal transpromontorial approach (METTA) for the removal of small vestibular schwannomas (VS) limited to the internal auditory canal (IAC), and introduce a modification without external auditory canal (EAC) closure. METHODS: Between August 2018 and February 2019, seven patients with intrameatal VS underwent surgery in our center, endoscopic transcanal transpromontorial approach was applied in the first 2 patients and the rest 5 patients were operated via METTA. Treatment outcomes including efficacy of tumor resection, facial nerve outcome, operation time and post-operative course were recorded and analyzed. RESULTS: All seven patients were pathologically confirmed to have intrameatal VS. Total tumor removal was achieved in all cases. Two patients experienced cerebrospinal fluid leakage which resolved spontaneously within 5 days. The average operation time was 161.41 ± 18.42 min. All patients presented normal facial nerve function 1 month after surgery. CONCLUSION: The METTA was effective in the removal of intrameatal VS. It can be an alternative surgical option for intrameatal VS with no serviceable hearing.

Immunological effects of the intraparenchymal administration of allogeneic and autologous adipose-derived mesenchymal stem cells after the acute phase of middle cerebral artery occlusion in rats.

BACKGROUND: Adipose-derived mesenchymal stem cell (ADMSC) therapy can promote recovery from cerebral ischemia; however, more information regarding appropriate sources of ADMSCs is required. This study was aimed at analyzing the immunogenicity of rat ADMSCs by comparing the immunological effects of intraparenchymal administration of allogeneic ADMSCs (allo-ADMSCs) and autologous ADMSCs (auto-ADMSCs) after the acute phase of middle cerebral artery occlusion (MCAO) in rats. METHODS: Allo- or auto-ADMSCs from rats (1 × 106 cells) were transplanted into Lewis rats 8 days post MCAO. The immunogenicity of ADMSCs was analyzed using coculture with T lymphocytes. The in vivo immune response induced by rat ADMSCs and the viability, migration, and differentiation of transplanted ADMSCs were detected using immunohistochemistry. Apoptosis within the populations of transplanted cells were detected using a TUNEL assay. Infarct volume was detected by 2,3,5-triphenyltetrazolium chloride staining. Post-treatment neurological function was evaluated using a modified neurological severity score and rotarod test. Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Compared with allo-ADMSCs, auto-ADMSCs showed lower immunogenicity and evoked weaker immunological responses. Allo-ADMSCs evoked significantly stronger protein expression of interleukin-2 and interferon-gamma, as well as the local accumulation of CD4+ T lymphocytes, CD8+ T lymphocytes, and microglial cells. This indicates that auto-ADMSCs may contribute to higher survival rates, longer survival time, wider migratory scope, and fewer apoptotic cells. In addition, a small number of transplanted auto-ADMSCs expressed astrocyte-like and neuron-like markers 28 days after transplantation. We did not observe surviving transplanted allo-ADMSCs at this time point. We also found that auto-ADMSCs induced a greater degree of functional recovery and a greater reduction in infarct volume than allo-ADMSCs 28 days after transplantation. CONCLUSIONS: Auto-ADMSCs were more effective than allo-ADMSCs in promoting recovery and reducing the infarct volume of MCAO rats. This could be associated with better viability, migratory ability, and differentiation potential, as well as a lower rate of apoptosis. Confirmation of the superiority of auto-ADMSCs and clarification of the underlying mechanisms will provide a theoretical basis for the improved clinical treatment of cerebral infarction.

Development of methods for detecting the fate of mesenchymal stem cells regulated by bone bioactive materials.

The fate of mesenchymal stem cells (MSCs) is regulated by biological, physical and chemical signals. Developments in biotechnology and materials science promoted the occurrence of bioactive materials which can provide physical and chemical signals for MSCs to regulate their fate. In order to design and synthesize materials that can precisely regulate the fate of MSCs, the relationship between the properties of materials and the fate of mesenchymal stem cells need to be clarified, in which the detection of the fate of mesenchymal stem cells plays an important role. In the past 30 years, a series of detection technologies have been developed to detect the fate of MSCs regulated by bioactive materials, among which high-throughput technology has shown great advantages due to its ability to detect large amounts of data at one time. In this review, the latest research progresses of detecting the fate of MSCs regulated by bone bioactive materials (BBMs) are systematically reviewed from traditional technology to high-throughput technology which is emphasized especially. Moreover, current problems and the future development direction of detection technologies of the MSCs fate regulated by BBMs are prospected. The aim of this review is to provide a detection technical framework for researchers to establish the relationship between the properties of BMMs and the fate of MSCs, so as to help researchers to design and synthesize BBMs better which can precisely regulate the fate of MSCs.