RIPK4 promotes oxidative stress and ferroptotic death through the downregulation of ACSM1.

One of the most critical axes for cell fate determination is how cells respond to excessive reactive oxygen species (ROS)-oxidative stress. Extensive lipid peroxidation commits cells to death via a distinct cell death paradigm termed ferroptosis. However, the molecular mechanism regulating cellular fates to distinct ROS remains incompletely understood. Through siRNA against human receptor-interacting protein kinase (RIPK) family members, we found that RIPK4 is crucial for oxidative stress and ferroptotic death. Upon ROS induction, RIPK4 is rapidly activated, and the kinase activity of RIPK4 is indispensable to induce cell death. Specific ablation of RIPK4 in kidney proximal tubules protects mice from acute kidney injury induced by cisplatin and renal ischemia/reperfusion. RNA sequencing revealed the dramatically decreased expression of acyl-CoA synthetase medium-chain (ACSM) family members induced by cisplatin treatment which is compromised in RIPK4-deficient mice. Among these ACSM family members, suppression of ACSM1 strongly augments oxidative stress and ferroptotic cell death with induced expression of ACS long-chain family member 4, an important component for ferroptosis execution. Our lipidome analysis revealed that overexpression of ACSM1 leads to the accumulation of monounsaturated fatty acids, attenuation of polyunsaturated fatty acid (PUFAs) production, and thereby cellular resistance to ferroptosis. Hence, knockdown of ACSM1 resensitizes RIPK4 KO cells to oxidative stress and ferroptotic death. In conclusion, RIPK4 is a key player involved in oxidative stress and ferroptotic death, which is potentially important for a broad spectrum of human pathologies. The link between the RIPK4-ASCM1 axis to PUFAs and ferroptosis reveals a unique mechanism to oxidative stress-induced necrosis and ferroptosis.

To target cellular senescence in diabetic kidney disease: the known and the unknown.

Cellular senescence represents a condition of irreversible cell cycle arrest, characterized by heightened senescence-associated beta-galactosidase (SA-ß-Gal) activity, senescence-associated secretory phenotype (SASP), and activation of the DNA damage response (DDR). Diabetic kidney disease (DKD) is a significant contributor to end-stage renal disease (ESRD) globally, with ongoing unmet needs in terms of current treatments. The role of senescence in the pathogenesis of DKD has attracted substantial attention with evidence of premature senescence in this condition. The process of cellular senescence in DKD appears to be associated with mitochondrial redox pathways, autophagy, and endoplasmic reticulum (ER) stress. Increasing accumulation of senescent cells in the diabetic kidney not only leads to an impaired capacity for repair of renal injury, but also the secretion of pro-inflammatory and profibrotic cytokines and growth factors causing inflammation and fibrosis. Current treatments for diabetes exhibit varying degrees of renoprotection, potentially via mitigation of senescence in the diabetic kidney. Targeting senescent cell clearance through pharmaceutical interventions could emerge as a promising strategy for preventing and treating DKD. In this paper, we review the current understanding of senescence in DKD and summarize the possible therapeutic interventions relevant to senescence in this field.

Podocyte Pathogenic Bone Morphogenetic Protein-2 Pathway and Immune Cell Behaviors in Primary Membranous Nephropathy.

Primary membranous nephropathy (PMN) is one of the leading causes of end-stage renal disease, and the most frequent cause of massive proteinuria in nondiabetic adults, resulting in fatal complications. However, the underlying pathomechanisms of PMN remain largely unclear. Here, single-cell RNA sequencing is employed to analyze kidney biopsies from eleven PMN patients and seven healthy subjects. Profiling 44 060 cells from patients allowed us to characterize the cellular composition and cell-type-specific gene expression in the PMN kidney. The complement-induced BMP2/pSMAD1/COL4 pathway is identified as the pathogenic pathway in podocytes, bridging two key events, i.e., complement system activation and glomerular basement membrane thickening in PMN. Augmented infiltration and activation of myeloid leukocytes and B lymphocytes are found, profiling delicate crosstalk of immune cells in PMN kidneys. Overall, these results provide valuable insights into the roles of podocytes and immune cells in PMN, and comprehensive resources toward the complete understanding of PMN pathophysiology.

Efficacy and safety of Yiqi Peiyuan granules for improving the short-term prognosis of patients with acute kidney injury: A multicenter, double-blind, placebo-controlled, randomized trial.

BACKGROUND: Yiqi Peiyuan (YQPY) prescription, a composite prescription of traditional Chinese medicine, has been used to prevent or delay the continued deterioration of renal function after acute kidney injury (AKI) in some institutions and has shown considerable efficacy. OBJECTIVE: This is the first randomized controlled trial to assess efficacy and safety of YQPY for improving short-term prognosis in adult patients with AKI. DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS: This is a prospective, double-blind, multicenter, randomized, and placebo-controlled clinical trial. A total of 144 enrolled participants were randomly allocated to two groups according to a randomization schedule. Participants, caregivers and investigators assessing the outcomes were blinded to group assignment. Patients in the YQPY group received 36 g YQPY granules twice a day for 28 days. Patients in the placebo group received a placebo in the same dose as the YQPY granules. MAIN OUTCOME MEASURES: The primary outcome was the change in the estimated glomerular filtration rate (eGFR) between baseline and after 4 and 24 weeks of treatment. The secondary outcomes were the change of serum creatinine (Scr) level between baseline and after treatment, and the incidence of endpoint events, defined as eGFR increasing by more than 25% above baseline, eGFR >75 mL/min per 1.73 m2 or the composite endpoint, which was defined as the sum of patients meeting either of the above criteria. RESULTS: Data from a total of 114 patients (59 in the YQPY group and 55 in the control group) were analyzed. The mean changes in eGFR and Scr in weeks 4 and 24 had no difference between the two groups. In further subgroup analysis (22 in the YQPY group and 31 in the control group), the mean change in eGFR after treatment for 4 weeks was 27.39 mL/min per 1.73 m2 in the YQPY group and 5.78 mL/min per 1.73 m2 in the placebo group, and the mean difference between groups was 21.61 mL/min per 1.73 m2 (P < 0.001). Thirteen (59.1%) patients in the YQPY group and 5 (16.1%) in the placebo group reached the composite endpoints (P = 0.002). During the intervention, 2 and 4 severe adverse events were reported in the YQPY and placebo groups, respectively. CONCLUSION: The YQPY granules can effectively improve the renal function of patients 4 weeks after the onset of AKI, indicating that it has good efficacy for improving short-term renal outcomes in patients with AKI. The YQPY granules may be a promising therapy for adults with AKI. TRIAL REGISTRATION: Chinese Clinical Trial Registry ChiCTR2100051723. Please cite this article as: Wu JJ, Zhang TY, Qi YH, Zhu MY, Fang Y, Qi CJ, Cao LO, Lu JF, Lu BH, Tang LM, Shen JX, Mou S. Efficacy and safety of Yiqi Peiyuan granules for improving the short-term prognosis of patients with acute kidney injury: a multicenter, double-blind, placebo-controlled, randomized trial. J Integr Med. 2024; 22(3): 279-285.

HINT2 protects against pressure overload-induced cardiac remodelling through mitochondrial pathways.

Histidine triad nucleotide-binding protein 2 (HINT2) is an enzyme found in mitochondria that functions as a nucleotide hydrolase and transferase. Prior studies have demonstrated that HINT2 plays a crucial role in ischemic heart disease, but its importance in cardiac remodelling remains unknown. Therefore, the current study intends to determine the role of HINT2 in cardiac remodelling. HINT2 expression levels were found to be lower in failing hearts and hypertrophy cardiomyocytes. The mice that overexpressed HINT2 exhibited reduced myocyte hypertrophy and cardiac dysfunction in response to stress. In contrast, the deficiency of HINT2 in the heart of mice resulted in a worsening hypertrophic phenotype. Further analysis indicated that upregulated genes were predominantly associated with the oxidative phosphorylation and mitochondrial complex I pathways in HINT2-overexpressed mice after aortic banding (AB) treatment. This suggests that HINT2 increases the expression of NADH dehydrogenase (ubiquinone) flavoprotein (NDUF) genes. In cellular studies, rotenone was used to disrupt mitochondrial complex I, and the protective effect of HINT2 overexpression was nullified. Lastly, we predicted that thyroid hormone receptor beta might regulate HINT2 transcriptional activity. To conclusion, the current study showcased that HINT2 alleviates pressure overload-induced cardiac remodelling by influencing the activity and assembly of mitochondrial complex I. Thus, targeting HINT2 could be a novel therapeutic strategy for reducing cardiac remodelling.

Unlocking the Potential of Pterostilbene: A Pharmaceutical Element for Aptamer-Based Nanomedicine.

Natural compounds like pterostilbene (PTE) have gained recognition for their various biological activities and potential health benefits. However, challenges related to bioavailability and limited clinical efficacy have prompted efforts to strengthen their therapeutic potential. To meet these challenges, we herein rationally designed and successfully synthesized a pharmaceutical phosphoramidite that allows for the programmable incorporation of PTE into oligonucleotides. The resultant aptamer-PTE conjugate can selectively bind to cancer cells, leading to a specific internalization and drug release. Moreover, compared with free PTE, the conjugate exhibits superior cytotoxicity in cancer cells. Specifically, in a zebrafish xenograft model, the nanomedicine effectively inhibits tumor growth and neovascularization, highlighting its potential for targeted antitumor therapy. This approach presents a promising avenue for harnessing the therapeutic potential of natural compounds via a nanomedicine solution.

Integrative ATAC-seq and RNA-seq analysis associated with diabetic nephropathy and identification of novel targets for treatment by dapagliflozin.

Dapagliflozin (DAPA) are clinically effective in improving diabetic nephropathy (DN). However, whether and how chromatin accessibility changed by DN responds to DAPA treatment is unclear. Therefore, we performed ATAC-seq, RNA-seq, and weighted gene correlation network analysis to identify the chromatin accessibility, the messenger RNA (mRNA) expression, and the correlation between clinical phenotypes and mRNA expression using kidney from three mouse groups: db/m mice (Controls), db/db mice (case group), and those treated with DAPA (treatment group). RNA-Seq and ATAC-seq conjoint analysis revealed many overlapping pathways and networks suggesting that the transcriptional changes of DN and DAPA intervention largely occured dependently on chromatin remodeling. Specifically, the results showed that some key signal transduction pathways, such as immune dysfunction, glucolipid metabolism, oxidative stress and xenobiotic and endobiotic metabolism, were repeatedly enriched in the analysis of the RNA-seq data alone, as well as combined analysis with ATAC-seq data. Furthermore, we identified some candidate genes (UDP glucuronosyltransferase 1 family, Dock2, Tbc1d10c, etc.) and transcriptional regulators (KLF6 and GFI1) that might be associated with DN and DAPA restoration. These reversed genes and regulators confirmed that pathways related to immune response and metabolism pathways were critically involved in DN progression.

Fractal Analysis of Left Ventricular Trabeculae in Patients with End-Stage Renal Disease: A Random Survival Tree Analysis.

BACKGROUND: The complexity of left ventricular (LV) trabeculae is related to the prognosis of several cardiovascular diseases. PURPOSE: To evaluate the prognostic value of LV trabecular complexity in patients with end-stage renal disease (ESRD). STUDY TYPE: Prospective outcome study. POPULATION: 207 participants on maintenance dialysis, divided into development (160 patients from 2 centers) and external validation (47 patients from a third center) cohorts, and 72 healthy controls. FIELD STRENGTH: 3.0T, steady-state free precession (SSFP) and modified Look-Locker imaging sequences. ASSESSMENT: All participants had their trabecular complexity quantified by fractal analysis using cine SSFP images. Patients were followed up every 2 weeks until April 2023, or endpoint events happened. Random Forest (RF) and Cox regression models including age, diabetes, LV mass index, mean basal fractal dimension (FD), and left atrial volume index, were developed to predict major adverse cardiac events (MACE). Patients were divided into low- and high-risk groups based on scores derived from the RF model and survival compared. STATISTICAL TESTS: Receiver operating characteristic curve analysis; Kaplan-Meier survival analysis with log rank tests; Harrel's C-index to assess model performance. A P value <0.05 was considered statistically significant. RESULTS: Fifty-five patients (26.57%) experienced MACE during a median follow-up time of 21.83 months. An increased mean basal FD (≥1.324) was associated with a significantly higher risk of MACE. The RF model (C-index: 0.81) had significantly better discrimination than the Cox regression model (C-index: 0.74). Participants of the external validation dataset classified into the high-risk group had a hazard of experiencing MACE increased by 12.29 times compared to those in the low-risk group. DATA CONCLUSION: LV basal FD was an independent predictor for MACE in patients with ESRD. Reliable risk stratification models could be generated based on LV basal FD and other MRI variables using RF analysis. LEVEL OF EVIDENCE: 2 TECHNICAL EFFICACY: Stage 2.

Single cell multi-omics of fibrotic kidney reveal epigenetic regulation of antioxidation and apoptosis within proximal tubule.

BACKGROUND: Until now, there has been no particularly effective treatment for chronic kidney disease (CKD). Fibrosis is a common pathological change that exist in CKD. METHODS: To better understand the transcriptional dynamics in fibrotic kidney, we make use of single-nucleus assay for transposase-accessible chromatin sequencing (snATAC-seq) and single-cell RNA sequencing (scRNA-seq) from GEO datasets and perform scRNA-seq of human biopsy to seek possible transcription factors (TFs) regulating target genes in the progress of kidney fibrosis across mouse and human kidneys. RESULTS: Our analysis has displayed chromatin accessibility, gene expression pattern and cell-cell communications at single-cell level in kidneys suffering from unilateral ureteral obstruction (UUO) or chronic interstitial nephritis (CIN). Using multimodal data, there exists epigenetic regulation producing less Sod1 and Sod2 mRNA within the proximal tubule which is hard to withstand oxidative stress during fibrosis. Meanwhile, a transcription factor Nfix promoting the apoptosis-related gene Ifi27 expression found by multimodal data was validated by an in vitro study. And the gene Ifi27 upregulated by in situ AAV injection within the kidney cortex aggravates kidney fibrosis. CONCLUSIONS: In conclusion, as we know oxidation and apoptosis are traumatic factors during fibrosis, thus enhancing antioxidation and inhibiting the Nfix-Ifi27 pathway to inhibit apoptosis could be a potential treatment for kidney fibrosis.

DDRGK1-mediated ER-phagy attenuates acute kidney injury through ER-stress and apoptosis.

Acute kidney injury (AKI) constitutes a prevalent clinical syndrome characterized by elevated morbidity and mortality rates, emerging as a significant public health issue. This study investigates the interplay between endoplasmic reticulum (ER) stress, unfolded protein response (UPR), and ER-associated degradation (ER-phagy) in the pathogenesis of AKI. We employed four distinct murine models of AKI-induced by contrast media, ischemia-reperfusion injury, cisplatin, and folic acid-to elucidate the relationship between ER-phagy, ER stress, and apoptosis. Our findings reveal a marked decrease in ER-phagy coinciding with an accumulation of damaged ER, elevated ER stress, and increased apoptosis across all AKI models. Importantly, overexpression of DDRGK1 in HK-2 cells enhanced ER-phagy levels, ameliorating contrast-induced ER stress and apoptosis. These findings unveil a novel protective mechanism in AKI, wherein DDRGK1-UFL1-mediated ER-phagy mitigates ER stress and apoptosis in renal tubular epithelial cells. Our results thereby contribute to understanding the molecular underpinnings of AKI and offer potential therapeutic targets for its treatment.

CGI1746 targets σ1R to modulate ferroptosis through mitochondria-associated membranes.

Ferroptosis is iron-dependent oxidative cell death. Labile iron and polyunsaturated fatty acid (PUFA)-containing lipids are two critical factors for ferroptosis execution. Many processes regulating iron homeostasis and lipid synthesis are critically involved in ferroptosis. However, it remains unclear whether biological processes other than iron homeostasis and lipid synthesis are associated with ferroptosis. Using kinase inhibitor library screening, we discovered a small molecule named CGI1746 that potently blocks ferroptosis. Further studies demonstrate that CGI1746 acts through sigma-1 receptor (σ1R), a chaperone primarily located at mitochondria-associated membranes (MAMs), to inhibit ferroptosis. Suppression of σ1R protects mice from cisplatin-induced acute kidney injury hallmarked by ferroptosis. Mechanistically, CGI1746 treatment or genetic disruption of MAMs leads to defective Ca2+ transfer, mitochondrial reactive oxygen species (ROS) production and PUFA-containing triacylglycerol accumulation. Therefore, we propose a critical role for MAMs in ferroptosis execution.

Left Ventricular Vertical Run-Length Nonuniformity MRI Adds Prognostic Value to MACE in Patients with End-Stage Renal Disease.

BACKGROUND: Vertical run-length nonuniformity (VRLN) is a texture feature representing heterogeneity within native T1 images and reflects the extent of cardiac fibrosis. In uremic cardiomyopathy, interstitial fibrosis was the major histological alteration. The prognostic value of VRLN in patients with end-stage renal disease (ESRD) remains unclear. PURPOSE: To evaluate the prognostic value of VRLN MRI in patients with ESRD. STUDY TYPE: Prospective. POPULATION: A total of 127 ESRD patients (30 participants in the major adverse cardiac events, MACE group). FIELD STRENGTH/SEQUENCE: 3.0 T/steady-state free precession sequence, modified Look-Locker imaging. ASSESSMENT: MRI image qualities were assessed by three independent radiologists. VRLN values were measured in the myocardium on the mid-ventricular short-axis slice of T1 mapping. Left ventricular (LV) mass, LV end-diastolic and end-systolic volume, as well as LV global strain cardiac parameters were measured. STATISTICAL TESTS: The primary endpoint was the incident of MACE from enrollment time to January 2023. MACE is a composite endpoint consisting of all-cause mortality, acute myocardial infarction, stroke, heart failure hospitalization, and life-threatening arrhythmia. Cox proportional-hazards regression was performed to test whether VRLN independently correlated with MACE. The intraclass correlation coefficients of VRLN were calculated to evaluate intraobserver and interobserver reproducibility. The C-index was computed to examine the prognostic value of VRLN. P-value <0.05 were considered statistically significant. RESULTS: Participants were followed for a median of 26 months. VRLN, age, LV end-systolic volume index, and global longitudinal strain remained significantly associated with MACE in the multivariable model. Adding VRLN to a baseline model containing clinical and conventional cardiac MRI parameters significantly improved the accuracy of the predictive model (C-index of the baseline model: 0.781 vs. the model added VRLN: 0.814). DATA CONCLUSION: VRLN is a novel marker for risk stratification toward MACE in patients with ESRD, superior to native T1 mapping and LV ejection fraction. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY STAGE: 2.

Metabolic Risk Profile and Graft Function Deterioration 2 Years After Kidney Transplant.

Importance: Studies exploring the association of body weight and metabolic status with graft function deterioration (GFD) after kidney transplantation have produced inconsistent findings. Few studies have examined whether metabolically healthy overweight or obesity (MHO) may contribute to GFD. Objective: To evaluate associations of overweight or obesity and metabolic disorders with GFD in recipients of kidney transplant. Design, Setting, and Participants: This multicenter retrospective cohort study was conducted from January 1, 2020, through June 30, 2021, with a follow-up period of 2 years after kidney transplantation. Participants included adult recipients of cadaveric kidney transplant in 4 transplantation centers in China. Participants were classified as 4 metabolic phenotypes according to their BMI and metabolic status. Data were analyzed from July to August 2023. Exposures: Overweight and obesity were characterized by body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) of 24 or greater. Metabolic disorder was identified by existence of a minimum of 2 of 4 conditions: hypertension, hyperglycemia, increased triglyceride, and decreased high-density lipoprotein cholesterol. Main Outcome and Measures: The main outcome was GFD, defined as a decrease in estimated glomerular filtration rate of at least 25% within 6 months to 2 years after transplant. Results: A total of 1260 adult recipients of cadaveric kidney transplant (mean [SD] age, 43.97 [11.51] years; 755 [59.92%] male) were included in the study, and 127 (10.08%) participants experienced the primary outcome of GFD during follow-up. After accounting for confounding factors in multivariable analyses, overweight or obesity (odds ratio [OR], 1.64; 95% CI, 1.10-2.44; P = .02) and metabolic disorder (OR, 1.71; 95% CI, 1.12-2.63; P = .01) were associated with increased risk of GFD. The MHO subgroup exhibited a greater risk for GFD (OR, 2.37; 95% CI, 1.01-5.57; P = .048) compared with participants who did not have overweight or obesity or metabolic disorder. All components of metabolic disorder, with the exception of elevated triglyceride, were associated with GFD. There was a dose-response association of number of metabolic disorder components (OR per 1 additional condition, 1.40; 95% CI, 1.20-1.63; P < .001) and BMI (OR per 1-unit increase, 1.90; 95% CI, 1.03-1.15; P = .002) with increased risk for GFD. A nonlinear association was observed between BMI and risk of GFD. Conclusions and Relevance: In this cohort study of recipients of cadaveric kidney transplant, individuals with overweight or obesity or metabolic disorder had a significantly higher risk of experiencing GFD. Individuals with MHO had an elevated risk for graft function deterioration. Additional studies with larger sample size and longer follow-up are necessary to validate our findings.

Dapagliflozin alleviates renal inflammation and protects against diabetic kidney diseases, both dependent and independent of blood glucose levels.

Introduction: Diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease worldwide. Therefore, efforts to understand DKD pathophysiology and prevent its development at the early phase are highly warranted. Methods: Here, we analyzed kidneys from healthy mice, diabetic mice, and diabetic mice treated with the sodium-glucose cotransporter 2 inhibitor dapagliflozin using ATAC and RNA sequencing. The findings were verified at the protein levels and in cultured cells. Results: Our combined method of ATAC and RNA sequencing revealed Csf2rb, Btla, and Isg15 as the key candidate genes associated with hyperglycemia, azotemia, and albuminuria. Their protein levels were altered together with multiple other inflammatory cytokines in the diabetic kidney, which was alleviated by dapagliflozin treatment. Cell culture of immortalized renal tubular cells and macrophages unraveled that dapagliflozin could directly effect on these cells in vitro as an anti-inflammatory agent independent of glucose concentrations. We further proved that dapagliflozin attenuated ischemia/reperfusion-induced chronic kidney injury and renal inflammation in mice. Discussion: Overall, our data emphasize the importance of inflammatory factors to the pathogenesis of DKD, and provide valuable mechanistic insights into the renoprotective role of dapagliflozin.

Fractal analysis: Left ventricular trabecular complexity cardiac MRI adds independent risks for heart failure with preserved ejection fraction in participants with end-stage renal disease.

PURPOSE: To measure left ventricular (LV) trabecular complexity by fractal dimension (FD) in patients with end-stage renal disease (ESRD), and assess whether FD was an independent risk factor for heart failure with preserved ejection fraction (HFpEF), or a significant predictor for adverse outcome in this population. METHODS: The study retrospectively enrolled 104 participants with ESRD who underwent 3.0 T cardiac magnetic resonance imaging (MRI) from June 2018 to November 2020. LV trabeculation was quantified with fractal analysis of short-axis cine slices to estimate the FD. Logistic regression analyses were used to evaluate FD and cardiac MRI parameters and to find independent risk predictors. Cox proportional hazard regression was used to investigate the association between FD and MACE. RESULTS: LV FD was higher in in the HFpEF group than those in the non-HFpEF group, with the greatest difference near the base of the ventricle. Age, minimum left atrial volume index, and LV mean basal FD were independent predictors for HFpEF in patients with ESRD. Combining the mean basal FD with typical predictive factors resulted in a C-index (0.902 vs 0.921), which was not significantly higher. Same improvements were found for net reclassification improvement [0.642; 95% confidence interval (CI), 0.254-1.029] and integrated discrimination index (0.026; 95% CI, 0.008-0.061). Participants with a LV global FD above the cutoff value (1.278) had higher risks of MACE in ESRD patients. CONCLUSIONS: LV trabecular complexity measured by FD was an independent risk factor for HFpEF, and a significant predictor for MACE among patients with ESRD.

Assessment of the Prognostic Value of MRI Left Ventricular Global Function Index (LVGFI) in Patients With End-Stage Renal Disease Under Maintenance Dialysis.

BACKGROUND: Left ventricular global function index (LVGFI) integrates LV volumetric and functional parameters. In patients with end-stage renal disease (ESRD), cardiac injury manifests as LV hypertrophy and dysfunction. However, the prognostic value of LVGFI in this population remains unclear. PURPOSE: To investigate the association of LVGFI with major adverse cardiac events (MACE) in patients with ESRD. STUDY TYPE: Prospective. POPULATION: One hundred fifty-eight ESRD patients (mean age: 54.1 ± 14.4 years; 105 male) on maintenance dialysis. FILED STRENGTH/SEQUENCE: 3.0 T, balanced steady-state free precession (bSSFP) cine and modified Look-Locker inversion recovery (MOLLI) sequences. ASSESSMENT: LV volumetric and functional parameters were determined from bSSFP images. LVGFI was calculated as the ratio of stroke volume to global volume and native T1 was determined from MOLLI T1 maps. MACE was recorded on follow up. Models were developed to predict MACE from conventional risk factors combined with LVGFI, GLS, native T1, and LV mass index (LVMI), respectively. Subgroup analyses were further performed in participants with LVEF above median. STATISTICAL TESTS: Cox proportional hazard regression and log-rank test were used to investigate the association between LVGFI and MACE. The predictive models were evaluated and compared using Harrell's C-statistics and DeLong tests. A P value <0.05 was considered statistically significant. RESULTS: Thirty-four MACE occurred during the median follow-up period of 26 months. The hazard of MACE increased by 114% for each 10% decrease in LVGFI in univariable analysis. The predictive model consisting of LVGFI (C-statistic: 0.724) had significantly better predictive performance than the others (all P < 0.001). These results were consistent in patients (N = 79) with LVEF > median (63.54%). DATA CONCLUSION: LVGFI is a novel marker for MACE risk stratification in patients with ESRD and was better able to predict MACE than native T1 mapping and GLS. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 3.

AMPK activation coupling SENP1-Sirt3 axis protects against acute kidney injury.

Acute kidney injury (AKI) is a critical clinical condition that causes kidney fibrosis, and it currently lacks specific treatment options. In this research, we investigate the role of the SENP1-Sirt3 signaling pathway and its correlation with mitochondrial dysfunction in proximal tubular epithelial cells (PTECs) using folic acid (FA) and ischemia-reperfusion-induced (IRI) AKI models. Our findings reveal that Sirt3 SUMOylation site mutation (Sirt3 KR) or pharmacological stimulation (metformin) protected mice against AKI and subsequent kidney inflammation and fibrosis by decreasing the acetylation level of mitochondrial SOD2, reducing mitochondrial reactive oxygen species (mtROS), and subsequently restoring mitochondrial ATP level, reversing mitochondrial morphology and alleviating cell apoptosis. In addition, AKI in mice was similarly alleviated by reducing mtROS levels using N-acetyl-L-cysteine (NAC) or MitoQ. Metabolomics analysis further demonstrated an increase in antioxidants and metabolic shifts in Sirt3 KR mice during AKI, compared with Sirt3 wild-type (WT) mice. Activation of the AMPK pathway using metformin promoted the SENP1-Sirt3 axis and protected PTECs from apoptosis. Hence, the augmented deSUMOylation of Sirt3 in mitochondria, activated through the metabolism-related AMPK pathway, protects against AKI and subsequently mitigated renal inflammation and fibrosis through Sirt3-SOD2-mtROS, which represents a potential therapeutic target for AKI.

Shear wave elastography parameters adds prognostic value to adverse outcome in kidney transplantation recipients.

INTRODUCTION: The tissue stiffness of donor kidneys in transplantation may increase due to pathological changes such as glomerulosclerosis and interstitial fibrosis, and those changes associate worse outcomes in kidney transplantation recipients. Ultrasound elastography is a noninvasive imaging examination with the ability to quantitatively reflect tissue stiffness. Aim of this study was to evaluate the prognostic value of ultrasound elastography for adverse kidney outcome in kidney transplantation recipients. METHODS: Shear wave elastography (SWE) examinations were performed by two independent operators in kidney transplantation recipients. The primary outcome was a composite of kidney graft deterioration, all-cause re-hospitalization, and all-cause mortality. Survival analysis was calculated by Kaplan-Meier curves with the log-rank test and Cox regression analysis. RESULTS: A total of 161 patients (mean age 46 years, 63.4% men) were followed for a median of 20.1 months. 27 patients (16.77%) reached the primary endpoint. The mean and median tissue stiffness at the medulla (hazard ratio: 1.265 and 1.229, respectively), estimated glomerular filtration rate (eGFR), and serum albumin level were associated with the primary outcome in univariate Cox regression. Adding mean or median medulla SWE to a baseline model containing eGFR and albumin significantly improved its discrimination (C-statistics: 0.736 for the baseline, 0.766 and 0.772 for the model added mean and median medulla SWE, respectively). CONCLUSION: The medullary tissue stiffness of kidney allograft measured by shear wave elastography may provide incremental prognostic value to adverse outcomes in kidney transplantation recipients. Including SWE parameters in kidney transplantation recipients management could be considered to improve risk stratification.

Reconfigurable Magnetic Liquid Building Blocks for Constructing Artificial Spinal Column Tissues.

All-liquid molding can be used to transform a liquid into free-form solid constructs, while maintaining internal fluidity. Traditional biological scaffolds, such as cured pre-gels, are normally processed in solid state, sacrificing flowability and permeability. However, it is essential to maintain the fluidity of the scaffold to truly mimic the complexity and heterogeneity of natural human tissues. Here, this work molds an aqueous biomaterial ink into liquid building blocks with rigid shapes while preserving internal fluidity. The molded ink blocks for bone-like vertebrae and cartilaginous-intervertebral-disc shapes, are magnetically manipulated to assemble into hierarchical structures as a scaffold for subsequent spinal column tissue growth. It is also possible to join separate ink blocks by interfacial coalescence, different from bridging solid blocks by interfacial fixation. Generally, aqueous biomaterial inks are molded into shapes with high fidelity by the interfacial jamming of alginate surfactants. The molded liquid blocks can be reconfigured using induced magnetic dipoles, that dictated the magnetic assembly behavior of liquid blocks. The implanted spinal column tissue exhibits a biocompatibility based on in vitro seeding and in vivo cultivating results, showing potential physiological function such as bending of the spinal column.