IntroductionStudies have demonstrated that mesenchymal stromal cells (MSCs) could reverse acute and chronic kidney injury by a paracrine or endocrine mechanism, and microvesicles (MVs) have been regarded as a crucial means of intercellular communication. In the current study, we focused on the therapeutic effects of human Wharton-Jelly MSCs derived microvesicles (hWJMSC-MVs) in renal ischemia/reperfusion injury and its potential mechanisms.MethodsMVs isolated from conditioned medium were injected intravenously in rats immediately after ischemia of the left kidney for 60 minutes. The animals were sacrificed at 24 hours, 48 hours and 2 weeks after reperfusion. The infiltration of inflammatory cells was identified by the immunostaining of CD68+ cells. ELISA was employed to determine the inflammatory factors in the kidney and serum von Willebrand Factor (VWF). Tubular cell proliferation and apoptosis were identified by immunostaining. Renal fibrosis was assessed by Masson’s tri-chrome straining and alpha-smooth muscle actin (α-SMA) staining. The CX3CL1 expression in the kidney was measured by immunostaining and Western blot, respectively. In vitro, human umbilical vein endothelial cells were treated with or without MVs for 24 or 48 hours under hypoxia injury to test the CX3CL1 by immunostaining and Western blot.ResultsAfter administration of hWJMSC-MVs in acute kidney injury (AKI) rats, renal cell apoptosis was mitigated and proliferation was enhanced, inflammation was also alleviated in the first 48 hours. MVs also could suppress the expression of CX3CL1 and decrease the number of CD68+ macrophages in the kidney. In the late period, improvement of renal function and abrogation of renal fibrosis were observed. In vitro, MVs could down-regulate the expression of CX3CL1 in human umbilical vein endothelial cells under hypoxia injury at 24 or 48 hours.ConclusionsA single administration of MVs immediately after ischemic AKI could ameliorate renal injury in both the acute and chronic stage, and the anti-inflammatory property of MVs through suppression of CX3CL1 may be a potential mechanism. This establishes a substantial foundation for future research and treatment.

Oxidative stress is known as one of the main contributors in renal ischemia/reperfusion injury (IRI). Here we hypothesized that Micro-vesicles (MVs) derived from human Wharton Jelly mesenchymal stromal cells (hWJMSCs) could protect kidney against IRI through mitigating oxidative stress. MVs isolated from hWJMSCs conditioned medium were injected intravenously in rats immediately after unilateral kidney ischemia for 60 min. The animals were sacrificed at 24h, 48h and 2 weeks respectively after reperfusion. Our results show that the expression of NOX2 and reactive oxygen species (ROS) in injured kidney tissues was declined and the oxidative stress was alleviated in MVs group at 24h and 48h in parallel with the reduced apoptosis and enhanced proliferation of cells. IRI-initiated fibrosis was abrogated by MVs coincident with renal function amelioration at 2 weeks. NOX2 was also found down-regulated by MVs both in human umbilical vein endothelial cells (HUVEC) and NRK-52E cell line under hypoxia injury model in vitro. In conclusion, a single administration of hWJMSC-MVs might protect the kidney by alleviation of the oxidative stress in the early stage of kidney IRI through suppressing NOX2 expression. Moreover, it could reduce the fibrosis and improved renal function.

Background/Aims: Anti-oxidation is an effective strategy for curing acute kidney injury (AKI). Herein, we suggest that extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) might play an anti-oxidative role by enhancing Nrf2/ARE activation in AKI. Methods: EVs isolated from the conditioned medium of human Wharton's Jelly mesenchymal stromal cells and human foreskin fibroblast were intravenously injected in rats immediately after 45 min of unilateral kidney ischemia. Animals were sacrificed 24 h after injury. Results: Results showed that renal tubular injury was alleviated and renal function was improved by MSC-EVs. Cell apoptosis and sNGAL levels, which reflect kidney cell injury, were reduced. Moreover, MSC-EVs decreased oxidative stress in injured kidney tissues and NRK-52E cells under hypoxia injury. Nrf2/antioxidant response element (ARE) enhancement and HO-1 up-regulation were further observed after MSC-EV treatment both in vivo and in vitro. Conclusions: MSC-EVs may protect against AKI possibly through anti-oxidation by enhancing Nrf2/ARE activation.

During acute kidney injury (AKI), tubular cell dedifferentiation initiates cell regeneration; hepatocyte growth factor (HGF) is involved in modulating cell dedifferentiation. Mesenchymal stem cell (MSC)-derived microvesicles (MVs) deliver RNA into injured tubular cells and alter their gene expression, thus regenerating these cells. We boldly speculated that MVs might induce HGF synthesis via RNA transfer, thereby facilitating tubular cell dedifferentiation and regeneration. In a rat model of unilateral AKI, the administration of MVs promoted kidney recovery. One of the mechanisms of action is the acceleration of tubular cell dedifferentiation and growth. Both in vivo and in vitro, rat HGF expression in damaged rat tubular cells was greatly enhanced by MV treatment. In addition, human HGF mRNA present in MVs was delivered into rat tubular cells and translated into the HGF protein as another mechanism of HGF induction. RNase treatment abrogated all MV effects. In the in vitro experimental setting, the conditioned medium of MV-treated injured tubular cells, which contains a higher concentration of HGF, strongly stimulated cell dedifferentiation and growth, as well as Erk1/2 signaling activation. Intriguingly, these effects were completely abrogated by either c-Met inhibitor or MEK inhibitor, suggesting that HGF induction is a crucial contributor to the acceleration of cell dedifferentiation and growth. All these findings indicate that MV-induced HGF synthesis in damaged tubular cells via RNA transfer facilitates cell dedifferentiation and growth, which are important regenerative mechanisms.

ObjectivesEmergence delirium (ED) is a common neurologic complication that can not only distress children and their families in the early postanesthetic period, but can also have adverse effects on children in the long-term. This study aimed to investigate the effects of single-dose dexmedetomidine on ED in children with sevoflurane anesthesia and to observe postoperative behavioral changes through long-term follow-up.MethodsPatients aged 2–7 years, American Society of Anesthesiologists class (ASA) I or II, scheduled for tonsillectomy with and without adenoidectomy were randomized to receive dexmedetomidine 0.5 μg/kg (Group D) or volume-matched normal saline (Group C) over 10 minutes after induction of anesthesia. The primary outcome was the incidence of ED within 30 minutes after extubation. Other outcomes were the incidence of pain, extubation time, post-anesthesia care unit (PACU) length of stay after extubation, adverse events, and the incidence of negative postoperative behavioral changes (NPOBCs).ResultsNinety children completed the study. Compared with the control group (Group C), dexmedetomidine decreased the incidence of ED (31.1% vs 53.3%; P=0.033) and pain (28.9% vs 57.8%; P=0.006), but it prolonged extubation time (P⩽0.001). PACU length of stay after extubation and the percentage of adverse events were similar between groups. The incidence of NPOBCs in Group D was significantly lower at 1 and 7 days after discharge (33.3% vs 60.0%; P=0.011% and 24.4% vs 46.7%; P=0.028, respectively) than it was in Group C, but no significant difference was found at the 30th day.ConclusionDexmedetomidine 0.5 μg/kg reduced the incidence of ED after sevoflurane anesthesia and might be used to prevent NPOBCs.Clinical trials registrationChiCTR1800016828.

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In our previous study, microvesicles (MVs) released from human Wharton's jelly mesenchymal stem cells (hWJ-MSCs) retard the growth of bladder cancer cells. We would like to know if MVs have a similar effect on human renal cell carcinoma (RCC). By use of cell culture and the BALB/c nu/nu mice xeno-graft model, the influence of MVs upon the growth and aggressiveness of RCC (786-0) was assessed. Cell counting kit-8 (CCK-8) assay, incidence of tumor, tumor size, Ki-67 or TUNEL staining was used to evaluate tumor cell growth in vitro or in vivo. Flow cytometry assay (in vitro) or examination of cyclin D1 expression (in vivo) was carried out to determine the alteration of cell cycle. The aggressiveness was analyzed by Wound Healing Assay (in vitro) or MMP-2 and MMP-9 expression (in vivo). AKT/p-AKT, ERK1/2/p-ERK1/2 or HGF/c-MET expression was detected by real-time PCR or western blot. Our data demonstrated that MVs promote the growth and aggressiveness of RCC both in vitro and in vivo. In addition, MVs facilitated the progression of cell cycle from G0/1 to S. HGF expression in RCC was greatly induced by MVs, associated with activation of AKT and ERK1/2 signaling pathways. RNase pre-treatment abrogated all effects of MVs. In summary, induction of HGF synthesis via RNA transferred by MVs activating AKT and ERK1/2 signaling is one of crucial contributors to the pro-tumor effect.

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