Intervertebral disc degeneration (IDD) is largely attributed to impaired endogenous repair. Nucleus pulposus-derived stem cells (NPSCs) senescence leads to endogenous repair failure. Small extracellular vesicles/exosomes derived from mesenchymal stem cells (mExo) have shown great therapeutic potential in IDD, while whether mExo could alleviate NPSCs senescence and its mechanisms remained unknown. We established a compression-induced NPSCs senescence model and rat IDD models to evaluate the therapeutic efficiency of mExo and investigate the mechanisms. We found that mExo significantly alleviated NPSCs senescence and promoted disc regeneration while knocking down thioredoxin (TXN) impaired the protective effects of mExo. TXN was bound to various endosomal sorting complex required for transport (ESCRT) proteins. Autocrine motility factor receptor (AMFR) mediated TXN K63 ubiquitination to promote the binding of TXN on ESCRT proteins and sorting of TXN into mExo. Knocking down exosomal TXN inhibited the transcriptional activity of nuclear factor erythroid 2-related factor 2 (NRF2) and activator protein 1 (AP-1). NRF2 and AP-1 inhibition reduced endogenous TXN production that was promoted by exosomal TXN. Inhibition of NRF2 in vivo diminished the anti-senescence and regenerative effects of mExo. Conclusively, AMFR-mediated TXN ubiquitination promoted the sorting of TXN into mExo, allowing exosomal TXN to promote endogenous TXN production in NPSCs via TXN/NRF2/AP-1 feed-forward circuit to alleviate NPSCs senescence and disc degeneration.

Objectives:To investigate the effect of fat suppression (FS) T 2WI on the interobserver agreement and diagnostic performance of clear cell likelihood score version 2.0 (ccLS v2.0) for clear cell renal cell carcinoma (ccRCC). Methods:In this retrospective study, the MR images of 111 patients with pathologically confirmed small renal masses (SRM) from January to December 2021 were analyzed in the First Medical Centre, Chinese PLA General Hospital. Of the 111 SRM, 82 cases were ccRCC and 29 cases were non-ccRCC. Two radiologists independently assessed ccLS scores based on T 2WI signal intensity (hypointense, isointense, hyperintense) and other MRI features (ccLS-T 2WI). After a one-month interval, the ccLS scores were independently evaluated utilizing the frequency-selective saturation FS-T 2WI and other MRI features (ccLS-FS-T 2WI). Fisher′s exact test was used to compare the difference in SRM signal intensity on T 2WI and FS-T 2WI. The weighted Kappa test was performed to assess the interobserver agreement of the two radiologists, and differences in the weighted Kappa coefficients were compared using the Gwet consistency coefficient. Receiver operating characteristic curves were drawn to evaluate the diagnostic performance of ccLS-T 2WI and ccLS-FS-T 2WI in diagnosing ccRCC, and the area under the curve (AUC) was compared utilizing the DeLong test. Results:The signal intensity of 111 SRM on T 2WI and FS-T 2WI had statistically significant difference (χ 2=126.33, P<0.001), consistent in 88 cases (79.3%) and varied in 23 cases (20.7%). The weighted Kappa coefficient of ccLS-T 2WI was 0.57 (95%CI 0.45-0.69) between the two radiologists, and the weighted Kappa coefficient of ccLS-FS-T 2WI was 0.55 (95%CI 0.42-0.67), and the difference was not statistically significant ( t=-0.65, P=0.520). The AUC of ccLS-T 2WI for ccRCC diagnosis was 0.92 (95%CI 0.86-0.97), while the AUC of ccLS-FS-T 2WI for ccRCC diagnosis was 0.91 (95%CI 0.85-0.96), and the difference was not statistically significant ( Z=1.50, P=0.133). Conclusions:The interobserver agreement and diagnostic performance of ccLS v2.0 based on T 2WI and FS-T 2WI sequences for ccRCC are comparable, and FS-T 2WI is applicable for the clinical application of ccLS v2.0.

Community health institutions have entered a new development stage of featured specialty construction. After 12 years of development, rehabilitation medicine now is the featured specialty of Fenglin Community Health Service Center. This article presents the train of thought and key points of specialty construction in primary care institutions based on the Fenglin′s experience. The positioning of featured specialty should be based on the community. The construction process should include 7 elements, namely, the standard operation procedure(SOP)of service system construction, the detailed publicity and implementation of the collaboration of specialists, prevention and control knowledge promotion for general practitioners, prevention and control knowledge education for community residents, service list, clinical efficacy evaluation, and clinical database. In the later iterations, the head of the department should always focus on the service system construction SOP and clinical database construction, and the rest parts can be assigned to the relevant team members.