Identification of a Novel ECM Remodeling Macrophage Subset in AKI to CKD Transition by Integrative Spatial and Single-Cell Analysis.

The transition from acute kidney injury (AKI) to chronic kidney disease (CKD) is a critical clinical issue. Although previous studies have suggested macrophages as a key player in promoting inflammation and fibrosis during this transition, the heterogeneity and dynamic characterization of macrophages are still poorly understood. Here, we used integrated single-cell RNA sequencing and spatial transcriptomic to characterize the spatiotemporal heterogeneity of macrophages in murine AKI-to-CKD model of unilateral ischemia-reperfusion injury. A marked increase in macrophage infiltration at day 1 was followed by a second peak at day 14 post AKI. Spatiotemporal profiling revealed that injured tubules and macrophages co-localized early after AKI, whereas in late chronic stages had spatial proximity to fibroblasts. Further pseudotime analysis revealed two distinct lineages of macrophages in this transition: renal resident macrophages differentiated into the pro-repair subsets, whereas infiltrating monocyte-derived macrophages contributed to chronic inflammation and fibrosis. A novel macrophage subset, extracellular matrix remodeling-associated macrophages (EAMs) originating from monocytes, linked to renal fibrogenesis and communicated with fibroblasts via insulin-like growth factors (IGF) signalling. In sum, our study identified the spatiotemporal dynamics of macrophage heterogeneity with a unique subset of EAMs in AKI-to-CKD transition, which could be a potential therapeutic target for preventing CKD development.

SAP130 released by damaged tubule drives necroinflammation via miRNA-219c/Mincle signaling in acute kidney injury.

Tubules injury and immune cell activation are the common pathogenic mechanisms in acute kidney injury (AKI). However, the exact modes of immune cell activation following tubule damage are not fully understood. Here we uncovered that the release of cytoplasmic spliceosome associated protein 130 (SAP130) from the damaged tubular cells mediated necroinflammation by triggering macrophage activation via miRNA-219c(miR-219c)/Mincle-dependent mechanism in unilateral ureteral obstruction (UUO) and cisplatin-induced AKI mouse models, and in patients with acute tubule necrosis (ATN). In the AKI kidneys, we found that Mincle expression was tightly correlated to the necrotic tubular epithelial cells (TECs) with higher expression of SAP130, a damaged associated molecule pattern (DAMP), suggesting that SAP130 released from damaged tubular cells may trigger macrophage activation and necroinflammation. This was confirmed in vivo in which administration of SAP130-rich supernatant from dead TECs or recombinant SAP130 promoted Mincle expression and macrophage accumulation which became worsen with profound tubulointerstitial inflammation in LPS-primed Mincle WT mice but not in Mincle deficient mice. Further studies identified that Mincle was negatively regulated via miR-219c-3p in macrophages as miR-219c-3p bound Mincle 3'-UTR to inhibit Mincle translation. Besides, lentivirus-mediated renal miR-219c-3p overexpression blunted Mincle and proinflammatory cytokine expression as well as macrophage infiltration in the inflamed kidney of UUO mice. In conclusion, SAP130 is released by damaged tubules which elicit Mincle activation on macrophages and renal necroinflammation via the miR-219c-3p-dependent mechanism. Results from this study suggest that targeting miR-219c-3p/Mincle signaling may represent a novel therapy for AKI.

Kim-1 Targeted Extracellular Vesicles: A New Therapeutic Platform for RNAi to Treat AKI.

BACKGROUND: AKI is a significant public health problem with high morbidity and mortality. Unfortunately, no definitive treatment is available for AKI. RNA interference (RNAi) provides a new and potent method for gene therapy to tackle this issue. METHODS: We engineered red blood cell-derived extracellular vesicles (REVs) with targeting peptides and therapeutic siRNAs to treat experimental AKI in a mouse model after renal ischemia/reperfusion (I/R) injury and unilateral ureteral obstruction (UUO). Phage display identified peptides that bind to the kidney injury molecule-1 (Kim-1). RNA-sequencing (RNA-seq) characterized the transcriptome of ischemic kidney to explore potential therapeutic targets. RESULTS: REVs targeted with Kim-1-binding LTH peptide (REVLTH) efficiently homed to and accumulated at the injured tubules in kidney after I/R injury. We identified transcription factors P65 and Snai1 that drive inflammation and fibrosis as potential therapeutic targets. Taking advantage of the established REVLTH, siRNAs targeting P65 and Snai1 were efficiently delivered to ischemic kidney and consequently blocked the expression of P-p65 and Snai1 in tubules. Moreover, dual suppression of P65 and Snai1 significantly improved I/R- and UUO-induced kidney injury by alleviating tubulointerstitial inflammation and fibrosis, and potently abrogated the transition to CKD. CONCLUSIONS: A red blood cell-derived extracellular vesicle platform targeted Kim-1 in acutely injured mouse kidney and delivered siRNAs for transcription factors P65 and Snai1, alleviating inflammation and fibrosis in the tubules.

Exosomal miR-125b-5p deriving from mesenchymal stem cells promotes tubular repair by suppression of p53 in ischemic acute kidney injury.

Mesenchymal stem cells-derived exosomes (MSC-exos) have attracted great interest as a cell-free therapy for acute kidney injury (AKI). However, the in vivo biodistribution of MSC-exos in ischemic AKI has not been established. The potential of MSC-exos in promoting tubular repair and the underlying mechanisms remain largely unknown. Methods: Transmission electron microscopy, nanoparticle tracking analysis, and western blotting were used to characterize the properties of human umbilical cord mesenchymal stem cells (hucMSCs) derived exosomes. The biodistribution of MSC-exos in murine ischemia/reperfusion (I/R) induced AKI was imaged by the IVIS spectrum imaging system. The therapeutic efficacy of MSC-exos was investigated in renal I/R injury. The cell cycle arrest, proliferation and apoptosis of tubular epithelial cells (TECs) were evaluated in vivo and in HK-2 cells. The exosomal miRNAs of MSC-exos were profiled by high-throughput miRNA sequencing. One of the most enriched miRNA in MSC-exos was knockdown by transfecting miRNA inhibitor to hucMSCs. Then we investigated whether this candidate miRNA was involved in MSC-exos-mediated tubular repair. Results:Ex vivo imaging showed that MSC-exos was efficiently homing to the ischemic kidney and predominantly accumulated in proximal tubules by virtue of the VLA-4 and LFA-1 on MSC-exos surface. MSC-exos alleviated murine ischemic AKI and decreased the renal tubules injury in a dose-dependent manner. Furthermore, MSC-exos significantly attenuated the cell cycle arrest and apoptosis of TECs both in vivo and in vitro. Mechanistically, miR-125b-5p, which was highly enriched in MSC-exos, repressed the protein expression of p53 in TECs, leading to not only the up-regulation of CDK1 and Cyclin B1 to rescue G2/M arrest, but also the modulation of Bcl-2 and Bax to inhibit TEC apoptosis. Finally, inhibiting miR-125b-5p could mitigate the protective effects of MSC-exos in I/R mice. Conclusion: MSC-exos exhibit preferential tropism to injured kidney and localize to proximal tubules in ischemic AKI. We demonstrate that MSC-exos ameliorate ischemic AKI and promote tubular repair by targeting the cell cycle arrest and apoptosis of TECs through miR-125b-5p/p53 pathway. This study provides a novel insight into the role of MSC-exos in renal tubule repair and highlights the potential of MSC-exos as a promising therapeutic strategy for AKI.

Bone marrow mesenchymal stem cells stimulated with low-intensity pulsed ultrasound: Better choice of transplantation treatment for spinal cord injury: Treatment for SCI by LIPUS-BMSCs transplantation.

Stem cell transplantation, especially treatment with bone marrow mesenchymal stem cells (BMSCs), has been considered a promising therapy for the locomotor and neurological recovery of spinal cord injury (SCI) patients. However, the clinical benefits of BMSCs transplantation remain limited because of the considerably low viability and inhibitory microenvironment. In our research, low-intensity pulsed ultrasound (LIPUS), which has been widely applied to clinical applications and fundamental research, was employed to improve the properties of BMSCs. The most suitable intensity of LIPUS stimulation was determined. Furthermore, the optimized BMSCs were transplanted into the epicenter of injured spinal cord in rats, which were randomized into four groups: (a) Sham group (n = 10), rats received laminectomy only and the spinal cord remained intact. (b) Injury group (n = 10), rats with contused spinal cord subjected to the microinjection of PBS solution. (c) BMSCs transplantation group (n = 10), rats with contused spinal cord were injected with BMSCs without any priming. (d) LIPUS-BMSCs transplantation group (n = 10), BMSCs stimulated with LIPUS were injected at the injured epicenter after contusion. Rats were then subjected to behavioral tests, immunohistochemistry, and histological observation. It was found that BMSCs stimulated with LIPUS obtained higher cell viability, migration, and neurotrophic factors expression in vitro. The rate of apoptosis remained constant. After transplantation of BMSCs and LIPUS-BMSCs postinjury, locomotor function was significantly improved in LIPUS-BMSCs transplantation group with higher level of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in the epicenter, and the expression of neurotrophic receptor was also enhanced. Histological observation demonstrated reduced cavity formation in LIPUS-BMSCs transplantation group when comparing with other groups. The results suggested LIPUS can improve BMSCs viability and neurotrophic factors expression in vitro, and transplantation of LIPUS-BMSCs could promote better functional recovery, indicating possible clinical application for the treatment of SCI.

The carcinogenicity of alendronate in patients with osteoporosis: evidence from cohort studies.

CONTEXT: Alendronate may relate to the incidence of cancers, especially esophageal and colon cancer. But the results are inconsistent in different studies. OBJECTIVE: To quantify the association between the use of alendronate and the occurrence of different types of cancer. DATA SOURCES: We searched Embase, Pubmed, CENTRAL, SIGLE and clinicaltrials.gov, up to 2014 June. STUDY SELECTION: Cohort studies reporting association between alendronate or bisphosphonate therapy including alendronate in patients with osteoporosis and risk of cancer were selected by two authors. DATA EXTRACTION: Two authors independently extracted the data. The Chi-square test and the I-square test were used for testing heterogeneity between studies. DATA SYNTHESIS: Eight cohort studies were included in the meta-analysis. Meta-analysis result manifested that alendronate significantly increased the incidence of lung cancer (HR 1.23, 95%CI 1.03 to 1.47, P value = 0.03), nevertheless, there was no significant difference after we excluded either Lee's 2012 study (HR 1.17, 95%CI 0.95 to 1.44, P value = 0.13) or Chiang's 2012 study (HR 1.47, 95%CI 1 to 2.17, P value = 0.05). For the incidence of colorectal cancer, no significant difference occurred (HR 0.91, 95%CI 0.74 to 1.13, P value = 0.39), but there was a positive relationship when we used fixed model (HR 0.85, 95%CI 0.78 to 0.93, P value = 0.004). For the incidence of liver cancer, there was no significant difference (HR 1.36, 95%CI 0.9 to 2.04, P value = 0.14), however, the result changed after we excluded Chiang's 2012 study (HR 1.69, 95%CI 1.03 to 2.77, P value = 0.04). There was no significant difference in other types of cancer. CONCLUSION: Based on current evidences, alendronate therapy may be associated with a high risk of lung cancer, may with an excess risk of liver cancer, a low risk of colorectal and no related risk of other cancers.

No difference in clinical outcome between fixed- and mobile-bearing TKA: a meta-analysis.

PURPOSE: To compare the clinical and radiographic results of fixed-bearing and mobile-bearing total knee arthroplasty (TKA). METHODS: We searched the PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar databases from 1966 to January 2012. No language restriction was applied. Reference lists of all the selected articles were hand-searched for any additional trials. Trial quality was assessed using the modified Jadad scale. Two authors independently extracted data from all eligible studies, including study design, participants, interventions, and outcomes (Knee Society Score, range of movement, radiolucent line, patient preference, walking support, pain score, and complications). The data were using fixed-effects or random-effects models with mean differences and risk ratios for continuous and dichotomous variables, respectively. RESULTS: A total of 24 studies involving 2,799 patients were identified in this analysis. Meta-analysis showed lower pain score (OR, 0.66, 95% CI 0.46, 0.94) in mobile-bearing TKA than fixed-bearing TKA. There was no significant difference between the two treatment groups regarding Knee Society Score (SMD, -0.17, 95% CI: -0.60, 0.26), range of movement (SMD, -0.05, 95% CI: -0.63, 0.53), radiolucent line (OR, 1.03, 95% CI 0.74, 1.44), patient preference (OR, 1.15, 95% CI 0.82, 1.61), walking support (OR, 1.07, 95% CI 0.68, 1.70), and complications (OR, 0.85, 95% CI 0.59, 1.21). CONCLUSIONS: The available evidence suggested that there was no significant difference between clinical and radiographic results of fixed-bearing and mobile-bearing TKA except for pain score. Regarding clinical relevance, the less incidence of pain could be the advantage for selecting mobile-bearing TKA. LEVEL OF EVIDENCE: II.

Tourniquet used in anterior cruciate ligament reconstruction: a system review.

PURPOSE: To identify whether routine use of a tourniquet is a better choice for anterior cruciate ligament reconstruction. METHOD: We searched Amed, British Nursing Index, Embase, Pubmed, Scopus, Cochrane Library and Google Scholar. We used revised Jadad score to evaluate the trial quality. Each reference list was viewed for any ignored studies. Two reviews independently extracted data from all eligible trials, including study design, patients' characteristics, interventions and outcomes. The available data were using random effects models with mean differences for continuous variables. RESULTS: The only meta-analysis indicated there was no significant difference in operative time between the tourniquet and non-tourniquet groups (mean differences -5.71, 95 % CI -12.40, 0.99). The remaining outcomes had variations in the outcome measures, so it was not possible to perform meta-analysis. CONCLUSIONS: There was insufficient evidence to support the hypothesis that patients would benefit from routinely applying a tourniquet. More high-quality randomized controlled trials were needed to test the result.

Evidence-based computer-navigated total hip arthroplasty: an updated analysis of randomized controlled trials.

BACKGROUND: Total hip arthroplasty (THA) has evolved over the years to be a reliable, reproducible, and successful orthopedic procedure. Nowadays, THA is increasingly performed on patients using less invasive, tissue-preserving techniques. Accordingly, the use of computer navigation in total joint arthroplasty has become more prevalent. However, there is still lack of high-quality evidence to verify the most effective technique for THA. METHODS: A search was conducted in PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar databases. Clinical trials published from 1966 to Feb 2012 that assess conventional techniques THA or computer-navigated techniques THA for placing the acetabular component. The main outcome measures included abduction angles, anteversion angles, percentage of acetabular outliers, operation time, decrease in Hb/24 h, and wound secretion/48 h. RESULTS: The pooled analysis across all studies showed a significant difference in anteversion angles and acetabular outliers (difference -0.22, 95% CI -0.67, 0.24; p = 0.346, I (2) = 71.9%) and (difference 8.34, 95% CI 4.15, 16.74; p = 0.000, I (2) = 0.0%). However, no significant difference in abduction angle and decrease in Hb/24 h (difference -0.22, 95% CI -0.67, 0.24; p = 0.346, I (2) = 71.9%) and (difference 0.03, 95% CI -0.36, 0.41; p = 0.888, I (2) = 0.0%). For the operation time, computer-navigated THA was longer (difference -0.73, 95% CI -1.32, -0.15; p = 0.014, I (2) = 74.4%). CONCLUSIONS: This meta-analysis demonstrated computer-navigated THA was a more favorable method for placing the acetabular component and decreased the number of acetabular cups implanted outside the desired range of alignment. More high-quality RCTs were needed to support the evidence.

Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures: an updated meta-analysis.

OBJECTIVES: To compare the outcomes of cemented and uncemented hemiarthroplasty for treating displaced femoral neck fractures. METHOD: We searched the PubMed, Medline, Embase, Cochrane Central Register of Controlled Trials, and Google Scholar databases from 1966 to Mar 2012. No language restriction was applied. Reference lists of all the selected articles were hand-searched for any additional trials. Trial quality was assessed using the modified Jadad Scale. Two authors independently extracted data from all eligible studies, including study design, participants, interventions, and outcomes (mortality, hospital stay, blood loss, operation time, residual pain, and complications). The data were using fixed-effects and random-effects models with mean differences and risk ratios for continuous and dichotomous variables, respectively. RESULTS: A total of 12 studies involving 1805 patients were identified in this analysis. Meta-analysis showed longer operation time (SMD, -0.43, 95 % CI -0.56, -0.30) in cemented versus uncemented hemiarthroplasty. There was no significant difference between the two treatment groups regarding mortality (OR, 1.08, 95 % CI 0.88, 1.34), hospital stay (SMD, -1.21, 95 % CI -2.24, -0.18), blood loss (SMD, -0.12, 95 % CI -0.33, 0.10), operation time (SMD, -0.43, 95 % CI -0.56, -0.30), residual pain (OR, 1.42, 95 % CI 0.99, 2.03), and complications (OR, 0.82, 95 % CI 0.63, 1.08). CONCLUSIONS: The available evidence suggested there was no significant difference between uncemented and cemented hemiarthroplasty in treating displaced femoral neck fractures.