Aerobic exercise attenuates high-fat diet-induced renal injury through kidney metabolite modulation in mice

PURPOSE

To investigate the preventive effect of aerobic exercise on renal damage caused by obesity.

METHODS

The mice in the Control (Con) and Control + Exercise (Con + Ex) groups received a standard chow diet for the 21-week duration of the study, while the High-fat diet (HFD) group and High-fat diet + Exercise (HFD + Ex) group were fed an HFD. Mice were acclimated to the laboratory for 1 week, given 12 weeks of being on their respective diets, and then the Con + Ex and HFD + Ex groups were subjected to moderate intensity aerobic treadmill running 45 min/day, 5 days/week for 8 weeks.

RESULTS

We found that HFD-induced obesity mainly impacts kidney glycerin phospholipids, glycerides, and fatty acyls, and aerobic exercise mainly impacts kidney glycerides, amino acids and organic acids as well as their derivatives. We identified 18 metabolites with significantly altered levels that appear to be involved in aerobic exercise mediated prevention of HFD-induced obesity and renal damage, half of which were amino acids and organic acids and their derivatives.

CONCLUSION

Aerobic exercise rewires kidney metabolites to reduce high-fat diet-induced obesity and renal injury.

Gadolinium Retention and Nephrotoxicity in a Mouse Model of Acute Ischemic Stroke: Linear Versus Macrocyclic Agents

BACKGROUND

Gadolinium (Gd)-based contrast agents (GBCAs) have been widely used for acute ischemic stroke (AIS) patients. GBCAs or AIS alone may cause the adverse effects on kidney tissue, respectively. However, whether GBCAs and AIS would generate a synergistic negative effect remains undefined.

PURPOSE

To evaluate synergistic negative effects of AIS and GBCAs on renal tissues in a mouse model of AIS, and to compare the differences of these negative effects between linear and macrocyclic GBCAs.

STUDY TYPE

Animal study.

ANIMAL MODEL

Seventy-two healthy mice underwent transient middle cerebral artery occlusion (tMCAO) and sham operation to establish AIS and sham model (N = 36/model). 5.0 mmol/kg GBCAs (gadopentetate or gadobutrol) or 250 μL saline were performed at 4.5 hours and 1 day after model establishing (N = 12/group).

ASSESSMENT

Inductively coupled plasma mass spectrometry (ICP-MS) was performed to detect Gd concentrations. Serum biochemical analyzer was performed to measure the serum creatinine (Scr), uric acid (UA), and blood urea nitrogen (BUN). Pathological staining was performed to observe tubular injury, cell apoptosis, mesangial hyperplasia, and interstitial fibrosis.

STATISTICAL TESTS

Two-way analysis of variances with post hoc Sidak's tests and independent-samples t-tests were performed. A P-value <0.05 was considered statistically significant.

RESULTS

AIS groups showed higher Gd concentration than sham group on day 1 p.i. regardless of gadopentetate or gadobutrol used. Increased total Gd concentration was also found in AIS + gadopentetate group compared with the sham group on day 28 p.i. Significantly higher rates for renal dysfunction, higher tubular injury scores, and higher numbers of apoptotic cells on days 1 or 28 p.i. were found for AIS mice injected with GBCA. AIS + gadopentetate group displayed more severe renal damage than the AIS + gadobutrol group.

DATA CONCLUSION

AIS and GBCAs may cause increased total Gd accumulation and nephrotoxicity in a mouse, especially linear GBCAs were used.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 4.

Resveratrol Improves Hyperuricemia and Ameliorates Renal Injury by Modulating the Gut Microbiota

Resveratrol (RES) has been reported to prevent hyperuricemia (HUA); however, its effect on intestinal uric acid metabolism remains unclear. This study evaluated the impact of RES on intestinal uric acid metabolism in mice with HUA induced by a high-fat diet (HFD). Moreover, we revealed the underlying mechanism through metagenomics, fecal microbiota transplantation (FMT), and 16S ribosomal RNA analysis. We demonstrated that RES reduced the serum uric acid, creatinine, urea nitrogen, and urinary protein levels, and improved the glomerular atrophy, unclear renal tubule structure, fibrosis, and renal inflammation. The results also showed that RES increased intestinal uric acid degradation. RES significantly changed the intestinal flora composition of HFD-fed mice by enriching the beneficial bacteria that degrade uric acid, reducing harmful bacteria that promote inflammation, and improving microbial function via the upregulation of purine metabolism. The FMT results further showed that the intestinal microbiota is essential for the effect of RES on HUA, and that Lactobacillus may play a key role in this process. The present study demonstrated that RES alleviates HFD-induced HUA and renal injury by regulating the gut microbiota composition and the metabolism of uric acid.

Effect of Focal Zone Size on Treatment Outcomes and Renal Injury Following Extracorporeal Shockwave Lithotripsy of Renal Calculi: A Prospective Randomized Study

Background: The narrower focal zone (FZ) size of modern lithotripter was considered as one of the factors that resulted in suboptimal treatment result of extracorporeal shockwave lithotripsy (SWL). Therefore, we investigate the efficacy and safety of standard narrow or extended (FZ) sizes in SWL for patients with renal stones. Materials and Methods: In this prospective study conducted between April 2018 and October 2022, patients with renal stones were randomized to receive SWL with either standard or extended FZ. Treatment was delivered using a Modulith SLX-F2 lithotripter with a maximum of 3000 shocks at 1.5 Hz. The primary outcome was treatment success 12 weeks after a single SWL session, defined as the absence of a stone or stone fragment <4 mm on computed tomography. Secondary outcomes included the incidence of perinephric hematoma, stone-free rate (SFR), and changes in the urinary levels of acute renal injury markers. Results: A total of 320 patients were recruited, and 276 patients were randomized into the two groups. The two groups had similar baseline parameters. The treatment success rate was significantly better for standard FZ (74.3%) than the extended FZ group (59.3%) (p = 0.009). Standard FZ also had a significantly better SFR (Grade-A, 36.8% vs 23.0%, p = 0.013) and less pain after treatment. Both groups had similar perinephric hematoma formation rates, unplanned hospital admission rates, and changes in urinary acute renal injury markers. Conclusions: The standard narrow FZ has better treatment efficacy and similar safety compared with the extended FZ during SWL for renal stones. This clinical trial has been registered in the public domain (CCRBCTR) under trial number CUHK_CCRB00510.

Impact of circadian clock protein Bmal1 on experimentally-induced periodontitis-associated renal injury

OBJECTIVES

To investigate the mechanism of circadian clock protein Bmal1 (Bmal1) on renal injury with chronic periodontitis, we established an experimental rat periodontitis model.

METHODS

Twelve male Wistar rats were randomly divided into control and periodontitis groups (n=6, each group). The first maxillary molars on both sides of the upper jaw of rats with periodontitis were ligated by using orthodontic ligature wires, whereas the control group received no intervention measures. After 8 weeks, clinical periodontal parameters, including probing depth, bleeding index, and tooth mobility, were evaluated in both groups. Micro-CT scanning and three-dimensional image reconstruction were performed on the maxillary bones of the rats for the assessment of alveolar bone resorption. Histopatholo-gical observations of periodontal and renal tissues were conducted using hematoxylin-eosin (HE) and periodic acid-Schiff (PAS) staining. Renal function indicators, such as creatinine, albumin, and blood urea nitrogen levels, and oxidative stress markers, including superoxide dismutase, glutathione, and malondialdehyde levels, were measured using biochemical assay kits. MitoSOX red staining was used to detect reactive oxygen species (ROS) content in the kidneys. The gene and protein expression levels of Bmal1, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in rat renal tissues were assessed using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemical staining.

RESULTS

Micro-CT and HE staining results showed significant bone resorption and attachment loss in the maxillary first molar region of the periodontitis group. Histological examination through HE and PAS staining revealed substantial histopathological damage to the renal tissues of the rats in the periodontitis group. The findings of the assessment of renal function and oxidative stress markers indicated that the periodontitis group exhibited abnormal levels of oxidative stress, whereas the renal function levels showed abnormalities without statistical significance. MitoSOX Red staining results showed that the content of ROS in the renal tissue of the periodontitis group was significantly higher than that of the control group, and RT-qPCR and immunohistochemistry results showed that the expression levels of Bmal1, Nrf2, and HO-1 in the renal tissues of the rats in the periodontitis group showed a decreasing trend.

CONCLUSIONS

Circadian clock protein Bmal1 plays an important role in the oxidative damage process involved in the renal of rats with periodontitis.

Fraxetin pretreatment alleviates cisplatin-induced kidney injury by antagonizing autophagy and apoptosis via mTORC1 activation

Cisplatin-induced kidney injury (CKI) is a common complication of chemotherapy. Fraxetin, derived from Fraxinus bungeana A. DC. bark, has antioxidant, anti-inflammatory, and anti-fibrotic effects. This study aims to investigate fraxetin's effects on CKI and its underlying mechanism in vivo and in vitro. Tubular epithelial cells (TECs) and mice were exposed to cisplatin with and without fraxetin preconditioning assess fraxetin's role in CKI. TECs autophagy was observed using transmission electron microscopy. Apoptosis levels in animal tissues were measured using TUNEL staining. The protective mechanism of fraxetin was explored through pharmacological and genetic regulation of mTORC1. Molecular docking was used to identify potential binding sites between fraxetin and mTORC1. The results indicated that fraxetin pretreatment reduced cisplatin-induced kidney injury in a time- and concentration-dependent way. Fraxetin also decreased autophagy in TECs, as observed through electron microscopy. Tissue staining confirmed that fraxetin pretreatment significantly reduced cisplatin-induced apoptosis. Inhibition of mTORC1 using rapamycin or siRNA reversed the protective effects of fraxetin on apoptosis and autophagy in cisplatin-treated TECs, while activation of mTORC1 enhanced fraxetin's protective effect. Molecular docking analysis revealed that fraxetin can bind to HEAT-repeats binding site on mTORC1 protein. In  summary, fraxetin pretreatment alleviates CKI by antagonizing autophagy and apoptosis via mTORC1 activation. This provides evidence for the potential therapeutic application of fraxetin in CKI.

Ameliorative impacts of sinapic acid against mercuric chloride-induced renal toxicity: role of antioxidants and inflammatory cytokines

Because of their beneficial properties, natural products, especially medicinal plants, are becoming increasingly popular worldwide and play a significant role in research. This study was aimed to evaluate the nephroprotective effect of sinapic acid against mercuric chloride-induced renal toxicity in mice. The mice were allocated to four groups named a normal group (G1), model group (G2; received HgCl2, 1 mg/kg bw), treatments groups (G3 and G4: received 50 and 100 mg/kg bw of sinapic acid together with HgCl2). Mice received HgCl2 remarkably showed alteration in all examined biochemical biomarkers (urea, creatinine, and bilirubin), and induced alteration in blood cell picture and anemia. HgCl2 intoxication decreased both systemic and renal antioxidant activity and induced over all oxidative stress as indicated by alteration in inflammation and oxidative stress associated markers. HgCl2 affected renal histology with leukocytic and inflammatory cell infiltration, fibrosis and tubular necrosis. Administration of sinapic acid (50 and 100 mg/kg bw) markedly restored the HgCl2-induced oxidative stress (serum and renal: MDA, GSH, CAT, SOD, and T-AOC), proinflammatory cytokines (serum and renal: TNF-α, IL-6, IL-1β, and PGE2) and restored the changes on biochemical markers, and hematological parameters (hemoglobin, erythrocytes, platelets, and leukocytes). Taken together, the results of the present study disclose that sinapic acid has the potential to attenuate HgCl2-induced renal toxicity and may be an ideal choice against mercury poisoning.

Integrating Network Pharmacology and Experimental Validation to Reveal the Mechanism of Vine Grape Tea Polyphenols on Hyperuricemia-Induced Renal Injury in Mice

Hyperuricemia (HUA) is a metabolic disease and contributes to renal injury (RI). Vine grape tea polyphenols (VGTP) have been widely used to treat HUA and RI. However, the potential mechanism of VGTP activity remains unclear. To explore the underlying mechanism of VGTP treatment for HUA-induced RI based on network pharmacology that is confirmed by an in vivo study. All ingredients of VGTP were retrieved using a Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform and Comparative Toxicogenomics Database systems. The related targets of HUA and RI were obtained from GeneCards and National Center for Biotechnology Information (NCBI) databases. Some ingredients and targets were selected for molecular docking verification. One hour after administering potassium oxonate (300 mg/kg), VGTP (50, 100, and 200 mg/kg/d) was orally administered to HUA mice for 4 weeks. Histopathology and western blotting were performed in renal tissue. Our results showed that VGTP significantly reduced blood urea nitrogen, creatinine, uric acid, and significantly improved the RI and fibrosis of HUA mice. There were 54 active ingredients and 62 targets of HUA-induced RI. Further studies showed that VGTP decreased the expression of Bax, cleaved caspase 3, transforming growth factor-β (TGF-β1), CHOP, p-STAT3, and P53, and increased Bcl-2 expression in renal tissue. The related signaling pathways have apoptosis, TGF-β1, P53 and STAT, and endoplasmic reticulum stress (ERS). In this study, VGTP exerted antihyperuricemic and anti fibrosis effects by regulating the apoptosis and ERS signaling pathways. VGTP is expected to become a drug for combating HUA and RI.

Perioperative acetaminophen is associated with reduced acute kidney injury after cardiac surgery

BACKGROUND

Cardiac surgery-associated acute kidney injury (AKI) is associated with increased postoperative morbidity and mortality. Evidence suggests an association between perioperative acetaminophen administration and decreased incidence of postoperative AKI in pediatric cardiac surgery patients; however, an effect in adults is unknown.

METHODS

All patients (n = 6192) undergoing coronary and/or valve surgery with a recorded Society of Thoracic Surgeons (STS) risk score at our institution between 2010 and 2018 were stratified by acetaminophen exposure on the day of surgery using institutional pharmacy records. AKI was determined using the Kidney Disease: Improving Global Outcomes (KDIGO) staging criteria. Logistic regression was used to analyze the association between perioperative acetaminophen and postoperative kidney injury or STS major morbidity. A sensitivity analysis using propensity score matching on the STS predicted risk of renal failure and cardiopulmonary bypass time was performed to account for time bias.

RESULTS

Perioperative acetaminophen exposure was associated with lower odds of stage 1 to 3 acute kidney injury (odds ratio [OR], 0.68; 95% CI, 0.56-0.83; P < .001) and decreased prolonged postoperative ventilation (OR, 0.53; 95% CI, 0.37-0.76; P < .001). A sensitivity analysis provided well-balanced (standard mean difference <0.10) groups of 401 pairs, in which acetaminophen was associated with a decreased incidence of postoperative AKI (OR, 0.7; 95% CI, 0.52-0.94; P = .016).

CONCLUSIONS

Exposure to acetaminophen on the day of surgery was associated with a decreased incidence of AKI in our patients undergoing cardiac surgery. These data serve as a measure of effect size to further explore the therapeutic potential of acetaminophen to reduce postoperative AKI after cardiac surgery and to elucidate the mechanisms involved.

Selenium prevented renal tissue damage in lipopolysaccharide-treated rats

OBJECTIVES

Kidney diseases are one of the common diseases, which are one of the main causes of death in society and impose costs on the health system of the society. A growing body of evidence has well documented that inflammatory responses and oxidative damage play a significant role in the progress of various kidney diseases.

METHODS

This study examined whether selenium (Sel) could prevent the detrimental influences of lipopolysaccharide (LPS) in rats. Four groups of Wistar rats were considered: control, LPS (1 mg/kg, i.p., for 14 days), LPS-Sel 1 (0.1 mg/kg, i.p., for 14 days), and LPS-Sel 2 (0.2 mg/kg, i.p., for 14 days).

RESULTS

Sel treatment markedly attenuated oxidative stress damage in the kidney tissue in LPS-induced renal toxicity. Generally, the administration of Sel resulted in improved antioxidant indicators such as catalase (CAT) and superoxide dismutase (SOD) activities, or total thiol content, and decreased malondialdehyde (MDA) in the kidney tissue. It also decreased interleukin-6 in kidney homogenates. Furthermore, Se treatment significantly inhibited the elevation of serum biochemical markers of kidney function including serum, BUN, and creatinine.

CONCLUSIONS

Based on the findings of the current study, it seems that the administration of Sel to LPS-treated rats improves renal function by reducing oxidative damage and inflammation in kidney tissue. However, more research is needed to reveal the accurate mechanisms for the effect of Sel on renal outcomes of LPS in human subjects.

The effect of proactive versus reactive treatment of hypotension on postoperative disability and outcome in surgical patients under anaesthesia (PRETREAT): clinical trial protocol and considerations

Background

Intraoperative hypotension has been extensively studied for its association with adverse outcomes. However, small sample sizes and methodological issues limit the causal inference that can be drawn.

Methods

In this multicentre, adaptive, randomised controlled trial, we will include 5000 adult inpatients scheduled for elective non-cardiac surgery under general or central neuraxial anaesthesia. Patients will be either randomly allocated to the intervention or care-as-usual group using computer-generated blocks of four, six, or eight, with an allocation ratio of 1:1. In the intervention arm patients will be divided into low-, intermediate-, and high-risk groups based on their likelihood to experience intraoperative hypotension, with resulting mean blood pressure targets of 70, 80, and 90 mm Hg, respectively. Anaesthesia teams will be provided with a clinical guideline on how to keep patients at their target blood pressure. During the first 6 months of the trial the intervention strategy will be evaluated and further revised in adaptation cycles of 3 weeks if necessary, to improve successful impact on the clinical process. The primary outcome is postoperative disability after 6 months measured with the World Health Organization Disability Assessment Score (WHODAS) 2.0 questionnaire.

Ethics and dissemination

This study protocol has been approved by the Medical Ethics Committee of the University Medical Centre Utrecht (20-749) and all protocol amendments will be communicated to the Medical Ethics Committee. The study protocol is in adherence with the Declaration of Helsinki and the guideline of Good Clinical Practice. Dissemination plans include publication in a peer-reviewed journal.

Clinical trial registration

The Dutch Trial Register, NL9391. Registered on 22 March 2021.

The Effect of Dextrose Hypotonic vs Saline Hydration on Methotrexate-Induced Nephrotoxicity in Male and Female Rats

Background

High-dose methotrexate (HDMTX) as a cytotoxic agent might cause various side effects. Hyperhydration has been implemented as the major strategy to decrease the potential risk of toxicities induced by HDMTX. This study aims to assess the renoprotective effect of hydration with dextrose water (DW) 5% versus normal saline (N/S) 0.9% against methotrexate (MTX) induced nephrotoxicity.

Materials and Methods

This experimental animal study has been conducted on 36 Wistar rats (200-250 g) categorized into six groups, including male (n = 6) and female (n = 6) rats receiving sodium chloride 0.9% saline plus MTX, DW 5% plus MTX, or MTX alone. By the fifth day after the MTX injection, biochemical indexes were measured. The rats were also sacrificed and renal specimens were evaluated microscopically to determine kidney tissue damage (KTD).

Results

The groups were not significantly different with regard to blood urea nitrogen (BUN) (P = 0.5), creatinine (Cr) (P = 0.24), kidney weight (P = 0.34), and urine flow (UF) (P = 0.5), while KTD score was remarkably less in the hydrated groups (P < 0.001). Weight loss in DW-treated rats was significantly more than N/S-treated ones, and creatinine clearance (CrCl) and urine load (UL) of Cr were statistically similar between males and females in the control group, but significantly lower among the DW5% treated males.

Conclusion

Based on the findings of this study, hydration with N/S was superior to DW5% for the prevention from HDMTX-induced nephrotoxicity. Besides, we found insignificant differences between male versus female rats in response to the hydration for HDMTX-induced renoprotection; however, females probably benefit more.

Prostacyclin Mitigates Renal Fibrosis by Activating Fibroblast Prostaglandin I 2 Receptor

SIGNIFICANCE STATEMENT

Renal fibrosis is a common pathologic process of progressive CKD. We have provided strong evidence that PGI 2 is an important component in the kidney injury/repairing process by reducing fibrosis and protecting renal function from declining. In our study, administration of a PGI 2 analog or selective PTGIR agonist after the acute injury ameliorated renal fibrosis. Our findings provide new insights into the role of PGI 2 in kidney biology and suggest that targeting PGI 2 /PTGIR may be a potential therapeutic strategy for CKD.

BACKGROUND

Prostanoids have been demonstrated to be important modulators to maintain tissue homeostasis in response to physiologic or pathophysiologic stress. Prostacyclin (PGI 2 ) is a member of prostanoids. While limited studies have shown that PGI 2 is involved in the tissue injury/repairing process, its role in renal fibrosis and CKD progression requires further investigation.

METHODS

Prostacyclin synthase ( Ptgis )-deficient mice, prostaglandin I 2 receptor ( Ptgir )-deficient mice, and an oral PGI 2 analog and selective PTGIR agonist were used to examine the role of PGI 2 in renal fibrosis in mouse models. We also analyzed the single-cell RNA-Seq data to examine the PTGIR -expressing cells in the kidneys of patients with CKD.

RESULTS

Increased PTGIS expression has been observed in fibrotic kidneys in both humans and mice. Deletion of the PTGIS gene aggravated renal fibrosis and decline of renal function in murine models. A PGI 2 analog or PTGIR agonist that was administered after the acute injury ameliorated renal fibrosis. PTGIR, the PGI 2 receptor, deficiency blunted the protective effect of the PGI 2 analog. Fibroblasts and myofibroblasts were the major cell types expressing PTGIR in the kidneys of patients with CKD. Deletion of PTGIR in collagen-producing fibroblastic cells aggravated renal fibrosis. The protective effect of PGI 2 was associated with the inhibition of fibroblast activation through PTGIR-mediated signaling.

CONCLUSIONS

PGI 2 is an important component in the kidney injury/repairing process by preventing the overactivation of fibroblasts during the repairing process and protecting the kidney from fibrosis and decline of renal function. Our findings suggest that PGI 2 /PTGIR is a potential therapeutic target for CKD.

Analysis of Thyroid Function in ANCA-Associated Vasculitis Patients with Renal Injury

BACKGROUND

Previous studies indicated common thyroid dysfunction in various kidney diseases. This study aimed to investigate the thyroid function in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV) with renal injury.

METHODS

Briefly, 174 patients diagnosed as having AAV with renal injury and without previous thyroid disease history were included in the retrospective and prospective study. The clinical parameters were collected and compared between different groups.

RESULTS

Of the patients included, 24 exhibited normal thyroid function, while 150 had thyroid dysfunction, including 55 (36.67%) with hypothyroidism. Those AAV patients with thyroid dysfunction showed different clinical parameters from those with normal thyroid function. The patients were followed up for a median of 68.6 (64.3; 72.8) months. Those with thyroid dysfunction were more prone to progressing to dialysis dependence compared to the group with normal thyroid function. Logistic regression analysis showed advanced age and decreased albumin as independent risk factors for thyroid dysfunction in patients with AAV. Survival analysis and multivariate Cox regression analysis showed that thyroid dysfunction was a risk factor for AAV patients with renal injury to progress to the endpoint of dialysis dependence.

CONCLUSION

Thyroid dysfunction, predominantly hypothyroidism, was commonly complicated in AAV patients with renal injury. AAV patients with thyroid dysfunction were presented with different clinical parameters and more prone to progressing to dialysis dependence compared to those with normal thyroid function.

Downregulating miR-184 relieves calcium oxalate crystal-mediated renal cell damage via activating the Rap1 signaling pathway

BACKGROUND

Renal calculi are a very prevalent disease with a high incidence. Calcium oxalate (CaOx) is a primary constituent of kidney stones. Our paper probes the regulatory function and mechanism of miR-184 in CaOx-mediated renal cell damage.

METHODS

CaOx was used to treat HK2 cells and human podocytes (HPCs) to simulate kidney cell damage. The qRT-PCR technique checked the profiles of miR-184 and IGF1R. The examination of cell proliferation was conducted employing CCK8. TUNEL staining was used to monitor cell apoptosis. Western blot analysis was used to determine the protein profiles of apoptosis-concerned related proteins (including Mcl1, Bcl-XL, and Caspase-3), the NF-κB, Nrf2/HO-1, and Rap1 signaling pathways. ELISA confirmed the levels of the inflammatory factors IL-6, TNF-α, MCP1, and ICAM1. The targeting relationship between miR-184 and IGF1R was validated by dual luciferase assay and RNA immunoprecipitation assay.

RESULTS

Glyoxylate-induced rat kidney stones model and HK2 and HPC cells treated with CaOx demonstrated an increase in the miR-184 profile. Inhibiting miR-184 relieved CaOx-mediated renal cell inflammation, apoptosis and oxidative stress and activated the Rap1 pathway. IGF1R was targeted by miR-184. IGF1R activation by IGF1 attenuated the effects of miR-184 on renal cell damage, and Hippo pathway suppression reversed the inhibitory effect of miR-184 knockdown on renal cell impairment.

CONCLUSIONS

miR-184 downregulation activates the Rap1 signaling pathway to ameliorate renal cell damage mediated by CaOx.

Immune thrombotic thrombocytopenic purpura in patients over 60 years of age: Diagnostic pitfalls and treatment strategy

Real-world registry studies of older patients with iTTP highlight diagnostic difficulties in comparison to patients less than 60 years of age with greater risk of renal injury, atypical neurological features and less profound cytopenia, which can result in diagnostic delays. However, there is no clear signal of significantly increased toxicity from full active treatment. Commentary on: Gómez-Seguí et al. Immune thrombotic thrombocytopenic purpura in older patients: results from the Spanish TTP Registry (REPTT). Br J Haematol 2023;203:860-871.

Identification of a circRNA-miRNA-mRNA network to explore the effects of circRNAs on renal injury in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. At present, the mechanism of non-coding RNA in renal injury in SLE patients is still unclear. A total of 64 DEcircRNAs, 75 DEmiRNAs, and 249 DEmRNAs were identified. We integrated 10 circRNAs, 10 miRNAs, and 88 target mRNAs into a circRNA-miRNA-mRNA network and obtained 9 hub genes (circ-0000006, miR-766-3p, miR-409-3p, miR-339-3p, miR-331-3p, miR-140-3p, miR-186-5p, miR-149-5p, PSME3). The ROC curve results showed that the diagnostic efficiency of 6 hub miRNA was higher than that of has_circ_0000006 and PSEME3. SsGSEA analysis revealed immune cell composition in SLE and control renal tissues, including 3 types of immune cells up-regulated (gamma delta T cell, effector memory CD4 T cell, central memory CD8 T cell) and 4 types down-regulated (memory B cell, mast cell, macrophage, immature dendritic cell, eosinophil) in SLE patients. In addition, PSME3 was negatively correlated with 3 up-regulated immune cells and positively correlated with 4 down-regulated immune cells in SLE patients. Our study provides a deeper understanding of the circRNA-related competing endogenous RNA regulatory mechanism in the renal injury of systemic lupus erythematosus.

Exploring the role of urinary extracellular vesicles in kidney physiology, aging, and disease progression

Extracellular vesicles (EVs), membranous vesicles present in all body fluids, are considered important messengers, carrying their information over long distance and modulating the gene expression profile of recipient cells. EVs collected in urine (uEVs) are mainly originated from the apical part of urogenital tract, following the urine flow. Moreover, bacterial-derived EVs are present within urine and may reflect the composition of microbiota. Consolidated evidence has established the involvement of uEVs in renal physiology, being responsible for glomerular and tubular cross talk and among different tubular segments. uEVs may also be involved in other physiological functions such as modulation of innate immunity, coagulation, or metabolic activities. Furthermore, it has been recently remonstrated that age, sex, endurance excise, and lifestyle may influence uEV composition and release, modifying their cargo. On the other hand, uEVs appear modulators of different urogenital pathological conditions, triggering disease progression. uEVs sustain fibrosis and inflammation processes, both involved in acute and chronic kidney diseases, aging, and stone formation. The molecular signature of uEVs collected from diseased patients can be of interest for understanding kidney physiopathology and for identifying diagnostic and prognostic biomarkers.

Occupational Heat Stress Recommendation Compliance Attenuates AKI Risk Compared with a Work-Rest Ratio-Matched, Positive Control Scenario

Occupational heat stress recommendations attenuate AKI risk compared with a work–rest ratio–matched positive control scenario. Heat-induced AKI risk is strongly related to peak core temperature. The peak change in serum creatinine largely paralleled peak changes in urinary [insulin-like growth factor-binding protein 7·tissue inhibitor metalloproteinase 2].

Investigation of the effects of ellagic, vanillic and rosmarinic acid on reperfusion-induced renal injury

INTRODUCTION

The aim of this study was to investigate the effects of ellagic, vanillic and rosmarinic acid on reperfusion-related kidney damage, developed in an experimental lower-extremity ischaemia/reperfusion (I/R) model.

METHODS

Forty-eight female Sprague-Dawley rats were divided into six groups. A median laparotomy and dissection were performed. In the I/R group, 60 minutes of ischaemia followed by 120 minutes of reperfusion was achieved. In addition one group was given 100 mg/kg ellagic acid, one group was given 12 mg/kg vanillic acid, one group was given 50 mg/kg rosmarinic acid and one group was given all three drugs 15 minutes before clamp removal. Bilateral kidney and blood samples were taken in all groups.

RESULTS

Tubular epithelial degeneration, necrosis of the tubule epithelium and vessel wall thickening were significantly higher in the I/R group. Some parameters in the groups that were given drugs were found to be lower than in the I/R group and close to that of the control group. Total oxidant status (TOS) and oxidative stress index (OSI) were significantly higher and total antioxidant status (TAS) was significantly lower in the I/R group. Although not statistically significant in the groups given drugs, TAS was higher, and TOS and OSI were lower than in the I/R group.

CONCLUSION

The antioxidant effect of ellagic, vanillic and rosmarinic acid administration may have beneficial effects on renal damage after reperfusion in acute lower-extremity ischaemia. This study is expected to provide information for future clinical trials.

ELABELA protects against diabetic kidney disease by activating high glucose-inhibited renal tubular autophagy

ELABELA (ELA), an endogenous ligand of the apelin receptor (also known as apelin peptide jejunum [APJ]), has been shown to decrease in the plasma of patients with diabetic kidney disease (DKD). In the current study, we explored the potential function as well as the underlying mechanisms of ELA in DKD. We first found that the ELA levels were decreased in the kidneys of DKD mice. Then, we found that ELA administration mitigated renal damage and downregulated the expression of fibronectin, collagen Ⅳ, and transforming growth factor-β1 in the db/db mice and the high glucose cultured HK-2 cells. Furthermore, the autophagy markers, Beclin-1 and LC3-Ⅱ/LC3-Ⅰ ratio, were significantly impaired in DKD, but the ELA treatment reversed these alterations. Mechanistically, the inhibitory effects of ELA on the secretion of fibrosis-associated proteins in high glucose conditions were blocked by pretreatment with 3-methyladenine (an autophagy inhibitor). In summary, these in vivo and in vitro results demonstrate that ELA effectively protects against DKD by activating high glucose-inhibited renal tubular autophagy, potentially serving as a novel therapeutic candidate for DKD.

Protective effects of royal jelly and Echinacea against moxifloxacin-induced renal and hepatic injury in rats

Antibiotic use, especially fluoroquinolones, has been linked to extensive renal and hepatic injury thus inflicts a considerable health problem. Fifty rats were allocated into five groups (n = 10). Group 1 represented the normal-control group. Group 2 received moxifloxacin only (MOX; 8 mg/kg/day, i.p.) for seven days and represented the MOX-control group. Groups 3, 4, and 5 received MOX for seven days accompanied by royal jelly (RJ; 100 mg/kg/day, p.o.), Echinacea (ECH; 40 mg/kg/day, p.o.), and a combination of both at the aforementioned doses respectively for 30 days. All groups were investigated for renal and hepatic function tests. Renal tissue content of kidney injury molecule-1 (KIM-1) along with renal and hepatic tissue contents of reduced glutathione (GSH) and malondialdehyde (MDA) were assessed for all groups. Histopathological examination was performed followed by immunohistochemical staining for caspase-3 in renal and hepatic tissues. MOX administration resulted in significant renal and hepatic damage. RJ and ECH significantly improved the serum parameters of renal and hepatic functions along with increasing GSH and decreasing MDA in renal and hepatic tissues. Renal contents of KIM-1 were also reduced. Moreover, RJ, ECH, and their combination amended MOX-induced histopathological changes and significantly reduced caspase-3 immunohistochemical staining in both renal and hepatic tissues. The current study is the first to elucidate the effect of RJ, ECH, and their combination against MOX-induced renal and hepatic injury in rats. The study suggests that these protective effects are mainly via the reduction of oxidative stress induced by MOX administration.

Super-Resolution Ultrasound Imaging of Renal Vascular Alterations in Zucker Diabetic Fatty Rats during the Development of Diabetic Kidney Disease

Individuals with diabetes at risk of developing diabetic kidney disease (DKD) are challenging to identify using currently available clinical methods. Prognostic accuracy and initiation of treatment could be improved by a quantification of the renal microvascular rarefaction and the increased vascular tortuosity during the development of DKD. Super-resolution ultrasound (SRUS) imaging is an in vivo technique capable of visualizing blood vessels at sizes below 75 µm. This preclinical study aimed to investigate the alterations in renal blood vessels' density and tortuosity in a type 2 diabetes rat model, Zucker diabetic fatty (ZDF) rats, as a prediction of DKD. Lean age-matched Zucker rats were used as controls. A total of 36 rats were studied, subdivided into ages of 12, 22, and 40 weeks. Measured albuminuria indicated the early stage of DKD, and the SRUS was compared with the ex vivo micro-computed tomography (µCT) of the same kidneys. Assessed using the SRUS imaging, a significantly decreased cortical vascular density was detected in the ZDF rats from 22 weeks of age compared to the healthy controls, concomitant with a significantly increased albuminuria. Already by week 12, a trend towards a decreased cortical vascular density was found prior to the increased albuminuria. The quantified vascular density in µCT corresponded with the in vivo SRUS imaging, presenting a consistently lower vascular density in the ZDF rats. Regarding vessel tortuosity, an overall trend towards an increased tortuosity was present in the ZDF rats. SRUS shows promise for becoming an additional tool for monitoring and prognosing DKD. In the future, large-scale animal studies and human trials are needed for confirmation.

Isoliensinine Attenuates Renal Fibrosis and Inhibits TGF-β1/Smad2/3 Signaling Pathway in Spontaneously Hypertensive Rats

Purpose

This study aimed to investigate the molecular mechanisms of isoliensinine, a kind of bibenzyl isoquinoline alkaloid which isolated from a TCM named Lotus Plumule (Nelumbo nucifera Gaertn), in treating renal interstitial fibrosis (RIF) by using RNA sequencing, KEGG analysis and in vivo experimental approaches.

Methods

Spontaneous hypertension rats (SHRs) were randomly assigned into five groups, consisting of SHR, SHR+Isoliensinine-L (2.5 mg/kg/day), SHR+Isoliensinine-M (5 mg/kg/day), SHR+Isoliensinine-H (10 mg/kg/day), and SHR+Valsartan (10 mg/kg/day) groups (n = 6 for each group). A control group of Wistar Kyoto rats (n = 6) was also included. Rats were treated intragastrically with isoliensinine, valsartan, or double-distilled water of equal volume for 10 weeks. To examine the therapeutic impact on hypertensive renal injury, fibrosis, and its underlying mechanisms, multiple techniques were employed, including hematoxylin and eosin staining, Masson trichrome staining, RNA sequencing, gene ontology (GO) function and pathway enrichment analysis and immunohistochemistry.

Results

Resultantly, the use of isoliensinine at different concentrations or valsartan showed significant improvement in renal pathological injury in SHRs. RNA sequencing and KEGG analysis uncovered 583 differentially expressed transcripts and pathways enriched in collagen formation and ECM-receptor interaction after treatment with isoliensinine. There was also a reduction in the increase of collagen and upregulation of collagen I & III, TGF-β1, p-Smad2, and p-Smad3 in the renal tissue of SHRs. Thus, isoliensinine ameliorated renal injury and collagen deposition in hypertensive rats, and inhibiting the activation of the TGF-β1/Smad2/3 pathway might be one of the underlying mechanisms.

Conclusion

This study showed that treatment with isoliensinine effectively reduced the renal injury and fibrosis in SHRs. In addition, isoliensinine inhibited the TGF-β1/Smad2/3 signaling in-vivo. These findings provided strong evidence for the therapeutic benefits of isoliensinine in combating renal injury and fibrosis.

Patient-Specific Pharmacokinetics and Dasatinib Nephrotoxicity

BACKGROUND

Dasatinib has been associated with nephrotoxicity. We sought to examine the incidence of proteinuria on dasatinib and determine potential risk factors that may increase dasatinib-associated glomerular injury.

METHODS

We examined glomerular injury through urine albumin-creatinine ratio (UACR) in 82 patients with chronic myelogenous leukemia who were on tyrosine-kinase inhibitor therapy for at least 90 days. t tests were used to compare mean differences in UACR, while regression analysis was used to assess the effects of drug parameters on proteinuria development while on dasatinib. We assayed plasma dasatinib pharmacokinetics using tandem mass spectroscopy and further described a case study of a patient who experienced nephrotic-range proteinuria while on dasatinib.

RESULTS

Participants treated with dasatinib ( n =32) had significantly higher UACR levels (median 28.0 mg/g; interquartile range, 11.5-119.5) than participants treated with other tyrosine-kinase inhibitors ( n =50; median 15.0 mg/g; interquartile range, 8.0-35.0; P < 0.001). In total, 10% of dasatinib users exhibited severely increased albuminuria (UACR >300 mg/g) versus zero in other tyrosine-kinase inhibitors. Average steady-state concentrations of dasatinib were positively correlated with UACR ( ρ =0.54, P = 0.03) and duration of treatment ( P = 0.003). There were no associations with elevated BP or other confounding factors. In the case study, kidney biopsy revealed global glomerular damage with diffuse foot process effacement that recovered on termination of dasatinib treatment.

CONCLUSIONS

Exposure to dasatinib was associated with a significant chance of developing proteinuria compared with other similar tyrosine-kinase inhibitors. Dasatinib plasma concentration significantly correlated with higher risk of developing proteinuria while receiving dasatinib.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_09_08_CJN0000000000000219.mp3.

Quercetin and Ferroptosis

Quercetin is a flavonoid present in apples, onions, tea, red wines, and berries, and it has shown different beneficial effects, such as providing cardiovascular protection, possessing anti-inflammatory properties, and demonstrating anticancer activity, among others. These diseases are related to oxidizing molecules such as ROS because these species react and induce the oxidation of cellular biomolecules, such as proteins, lipids, DNA, or carbohydrates, which alters cellular homeostasis. Regarding lipids, the oxidation of these molecules induces lipid hydroperoxides which, if not decreased, particularly by GPX4, produce highly reactive aldehydes such as 4HNE and MDA. These oxidative conditions induce ferroptosis, a type of cell death associated with oxidation that differs from other types of cell death, such as apoptosis, necrosis, or autophagy. The induction of ferroptosis is desired in some diseases, such as cancer, but in others, such as cardiovascular diseases, this type of cell death is not wanted. The possible effects of quercetin associated with reducing or inducing ferroptosis have not been reviewed. Thus, this review focuses on the ability of quercetin to produce ferroptosis in diseases such as cancer as a treatment option and, conversely, on its role in deactivating ferroptosis to alleviate diseases such as cardiovascular diseases.

Associations of Biomarkers of Kidney Tubule Health, Injury, and Inflammation with Left Ventricular Hypertrophy in Children with CKD

Key Points

Higher plasma and urine kidney injury molecule-1, urine monocyte chemoattractant protein-1, and lower urine alpha-1-microglobulin were associated with left ventricular hypertrophy, even after adjustment for confounders. Biomarkers of tubular injury, dysfunction, and inflammation may indicate the severity of kidney pathology and are associated with left ventricular hypertrophy.

Background

Left ventricular hypertrophy (LVH) is common in children with CKD and is associated with an increased risk of cardiovascular disease and mortality. We have shown that several plasma and urine biomarkers are associated with increased risk of CKD progression. As CKD is associated with LVH, we sought to investigate the association between the biomarkers and LVH.

Methods

In the CKD in Children Cohort Study, children aged 6 months to 16 years with an eGFR of 30–90 ml/min per 1.73 m2 were enrolled at 54 centers in the United States and Canada. We measured plasma biomarkers kidney injury molecule-1 (KIM-1), tumor necrosis factor receptor-1, tumor necrosis factor receptor-2, soluble urokinase-type plasminogen activator receptor and urine KIM-1, monocyte chemoattractant protein-1 (MCP-1), YKL-40, alpha-1-microglobulin (alpha-1m), and epidermal growth factor in stored plasma and urine collected 5 months after enrollment. Echocardiograms were performed 1 year after enrollment. We assessed the cross-sectional association between the log2 biomarker levels and LVH (left ventricular mass index greater than or equal to the 95th percentile) using a Poisson regression model, adjusted for age, sex, race, body mass index, hypertension, glomerular diagnosis, urine protein-to-creatinine ratio, and eGFR at study entry.

Results

Among the 504 children, LVH prevalence was 12% (n =59) 1 year after enrollment. In a multivariable-adjusted model, higher plasma and urine KIM-1 and urine MCP-1 concentrations were associated with a higher prevalence of LVH (plasma KIM-1 prevalence ratio [PR] per log2: 1.27, 95% confidence interval [CI], 1.02 to 1.58; urine KIM-1 PR: 1.21, 95% CI, 1.11 to 1.48; and urine MCP-1 PR: 1.18, 95% CI, 1.04 to 1.34). After multivariable adjustment for covariates, lower urine alpha-1m was also associated with a higher prevalence of LVH (PR: 0.90, 95% CI, 0.82 to 0.99).

Conclusions

Higher plasma and urine KIM-1, urine MCP-1, and lower urine alpha-1m were each associated with LVH prevalence in children with CKD. These biomarkers may better inform risk and help elucidate the pathophysiology of LVH in pediatric CKD.

Association between AGTR1 (c.1166 A>C) Polymorphisms and Kidney Injury in Hypertension

BACKGROUND

High blood pressure is the main cause of cardiovascular diseases. Kidney damage is one of the most common organ secondary damage to hypertension. The study of hypertension gene polymorphisms is an important means of precision treatment of primary hypertension.

OBJECTIVES

The objective of this study was to explore the relationship between AGTR1 (c.1166 A>C) gene polymorphisms and hypertension combined with kidney damage, while exploring the relationship between codominant, dominant and recessive gene model and hypertension with kidney injury and the susceptibility of different genotypes to hypertension with kidney injury.

METHODS

The distribution of AGTR1 polymorphism in the AGTR1 in hypertensive patients (hypertension group, 292 patients) and hypertension with kidney injury patients (44 patients) were detected and compared by PCR-melting curve method.

RESULTS

The genotype distribution of hypertension and combined groups met Hardy-Weinberg equilibrium (p > 0.05); the distribution difference between the three genotypes was statistically significant (p < 0.05), the codominant, dominant and recessive distribution frequency of genotypes (p < 0.05), and no difference between A allele and C allele (p > 0.05).

CONCLUSIONS

Our study identified the relationship of AGTRA (c.1166 A>C) with hypertension combined with renal injury, and compared the susceptibility of different genetic models, which may provide novel targets for precision gene therapy of hypertension.

CLINICAL TRIAL REGISTRATION

URL: https://www.chictr.org.cn/indexEN.html; Unique identifier: ChiCTR2100051472.

Protective Action Mechanisms of Launaea mucronata Extract and Its Nano-Formulation against Nephrotoxicity in Rats as Revealed via Biochemical, Histopathological, and UPLC-QTOF-MS/MS Analyses

Plants belonging to the Launaea genus have been extensively utilized ethnopharmacologically to treat a variety of diseases, including kidney disorders. Chromium is a common industrial pollutant that has been linked to kidney disease. The present work was designed for the investigation of the UPLC-QTOF-MS/MS metabolite profile of the L. mucronate ethanolic extract (LME), along with assessing the mechanistic protective actions of LME and its nano-silver formulation (LMNS) against K₂Cr₂O₇-induced nephrotoxicity in rats. LMNE was successfully biosynthesized and confirmed using UV-Visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM). The nephroprotective effects of LME and LMNE was assessed in rats exposed to potassium dichromate (K₂Cr₂O₇, 15 mg/kg BW) to cause nephrotoxicity. LME and LMNS, separately, were administered twice daily for 14 days at doses of 200 and 400 mg/kg BW, respectively. The kidney function, catalase, UGT, Nrf2, PGE2, Cox-2, ERK, and MAPK levels in renal tissue were all assessed, along with histopathological examinations for exploring their ameliorative effects. Forty-five bioactive metabolites were annotated belonging to flavonoids, phenolic and organic acids, coumarins, and fatty acids. Metabolite profiling revealed that chlorogenic acid, apigenin, and luteolin glycosides were the main phenolics, with chlorogenic acid-O-hexoside reported for the first time in LME. The findings revealed that the serum kidney function indicators (urea and creatinine) were markedly elevated in K₂Cr₂O₇-intoxicated rats. Furthermore, inflammatory indicators (COX-2 and PGE2), MAPK, and ERK were all markedly elevated in kidney tissue, whereas catalase, UGT, and Nrf2 levels were downregulated. Histological and immunohistochemical assays confirmed the toxic effects of K₂Cr₂O₇ in the kidneys. In contrast, the administration of LME and LMNS prior to K₂Cr₂O₇ considerably improved the architecture of the renal tissue, while also restoring levels of most biochemical markers. Functioning via the inhibition of the MAPK/ERK pathway, activating Nrf2, and modifying the antioxidant and metabolic enzymes, LME and LMNS exerted their nephroprotective effects against K₂Cr₂O₇-induced toxicity.

Mitochondrial Oxidative Metabolism: An Emerging Therapeutic Target to Improve CKD Outcomes

Chronic kidney disease (CKD) predisposes one toward end-stage renal disease (ESRD) and its associated morbidity and mortality. Significant metabolic perturbations in conjunction with alterations in redox status during CKD may induce increased production of reactive oxygen species (ROS), including superoxide (O₂^●-) and hydrogen peroxide (H₂O₂). Increased O₂^●- and H₂O₂ may contribute to the overall progression of renal injury as well as catalyze the onset of comorbidities. In this review, we discuss the role of mitochondrial oxidative metabolism in the pathology of CKD and the recent developments in treating CKD progression specifically targeted to the mitochondria. Recently published results from a Phase 2b clinical trial by our group as well as recently released data from a ROMAN: Phase 3 trial (NCT03689712) suggest avasopasem manganese (AVA) may protect kidneys from cisplatin-induced CKD. Several antioxidants are under investigation to protect normal tissues from cancer-therapy-associated injury. Although many of these antioxidants demonstrate efficacy in pre-clinical models, clinically relevant novel compounds that reduce the severity of AKI and delay the progression to CKD are needed to reduce the burden of kidney disease. In this review, we focus on the various metabolic pathways in the kidney, discuss the role of mitochondrial metabolism in kidney disease, and the general involvement of mitochondrial oxidative metabolism in CKD progression. Furthermore, we present up-to-date literature on utilizing targets of mitochondrial metabolism to delay the pathology of CKD in pre-clinical and clinical models. Finally, we discuss the current clinical trials that target the mitochondria that could potentially be instrumental in advancing the clinical exploration and prevention of CKD.

Association of psoriasis with chronic kidney disease and end-stage renal disease: a systematic review and meta-analysis

Background and objective

Previous studies have shown that patients with psoriasis are at higher risk of developing chronic kidney disease (CKD) and end-stage renal disease (ESRD) compared with general population; however, data on the differences in the occurrence of CKD and ESRD between patients with psoriasis and non-psoriatic controls are limited and inconsistent. The aim of this study was to carry out a comparison of the probability of suffering CKD and ESRD in patients with or without psoriasis by conducting a meta-analysis of cohort studies.

Methods

Cohort studies on PubMed, Web of Science, Embase and Cochrane Library by March, 2023 were searched for. The studies were screened according to pre-established inclusion criteria. Hazard ratios (HRs) and a 95% confidence intervals (CIs) for the renal outcomes among patients with psoriasis were calculated using the random-effect, generic inverse variance method. Subgroup analysis was related to the severity of psoriasis.

Results

A total of seven retrospective cohort studies were included, including 738,104 psoriasis patients and 3,443,438 non-psoriasis subjects, published from 2013 to 2020. Compared to controls without psoriasis, patients with psoriasis had an increased risk of CKD and ESRD, with pooled hazard ratios of 1.65 (95% CI, 1.29-2.12) and 1.37 (95% CI, 1.14-1.64), respectively. Besides, the incidence of CKD and ESRD is positively correlated with the severity of psoriasis.

Conclusion

This study showed that compared to patients without psoriasis, patients with psoriasis, especially those with severe psoriasis, had a significantly increased risk of developing CKD and ESRD. Considering the limitations of this meta-analysis, more high-quality and well-designed studies are needed in the future to validate our findings.

Targeting immunometabolism during cardiorenal injury: roles of conventional and alternative macrophage metabolic fuels

Macrophages play critical roles in mediating and resolving tissue injury as well as tissue remodeling during cardiorenal disease. Altered immunometabolism, particularly macrophage metabolism, is a critical underlying mechanism of immune dysfunction and inflammation, particularly in individuals with underlying metabolic abnormalities. In this review, we discuss the critical roles of macrophages in cardiac and renal injury and disease. We also highlight the roles of macrophage metabolism and discuss metabolic abnormalities, such as obesity and diabetes, which may impair normal macrophage metabolism and thus predispose individuals to cardiorenal inflammation and injury. As the roles of macrophage glucose and fatty acid metabolism have been extensively discussed elsewhere, we focus on the roles of alternative fuels, such as lactate and ketones, which play underappreciated roles during cardiac and renal injury and heavily influence macrophage phenotypes.

Metalloporphyrins as Tools for Deciphering the Role of Heme Oxygenase in Renal Immune Injury

Renal immune injury is a frequent cause of end-stage renal disease, and, despite the progress made in understanding underlying pathogenetic mechanisms, current treatments to preserve renal function continue to be based mainly on systemic immunosuppression. Small molecules, naturally occurring biologic agents, show considerable promise in acting as disease modifiers and may provide novel therapeutic leads. Certain naturally occurring or synthetic Metalloporphyrins (Mps) can act as disease modifiers by increasing heme oxygenase (HO) enzymatic activity and/or synthesis of the inducible HO isoform (HO-1). Depending on the metal moiety of the Mp employed, these effects may occur in tandem or can be discordant (increased HO-1 synthesis but inhibition of enzyme activity). This review discusses effects of Mps, with varying redox-active transitional metals and cyclic porphyrin cores, on mechanisms underlying pathogenesis and outcomes of renal immune injury.

Evaluation of aristolochic acid Ι nephrotoxicity in mice via 1H NMR quantitative metabolomics and network pharmacology approaches

Background

Although many studies have shown that herbs containing aristolochic acids can treat various human diseases, AAΙ in particular has been implicated as a nephrotoxic agent.

Methods and results

Here, we detail the nephrotoxic effect of AAΙ via an approach that integrated 1H NMR-based metabonomics and network pharmacology. Our findings revealed renal injury in mice after the administration of AAΙ. Metabolomic data confirmed significant differences among the renal metabolic profiles of control and model groups, with significant reductions in 12 differential metabolites relevant to 23 metabolic pathways. Among them, there were seven important metabolic pathways: arginine and proline metabolism; glycine, serine, and threonine metabolism; taurine and hypotaurine metabolism; ascorbate and aldehyde glycolate metabolism; pentose and glucosinolate interconversion; alanine, aspartate, and glutamate metabolism; and glyoxylate and dicarboxylic acid metabolism. Relevant genes, namely, nitric oxide synthase 1 (NOS1), pyrroline-5-carboxylate reductase 1 (PYCR1), nitric oxide synthase 3 (NOS3) and glutamic oxaloacetic transaminase 2 (GOT2), were highlighted via network pharmacology and molecular docking techniques. Quantitative real-time PCR findings revealed that AAI administration significantly downregulated GOT2 and NOS3 and significantly upregulated NOS1 and PYCR1 expression and thus influenced the metabolism of arginine and proline.

Conclusion

This work provides a meaningful insight for the mechanism of AAΙ renal injury.

Elevated soluble urokinase plasminogen activator receptor is associated with renal dysfunction in a Chlorocebus atheiops COVID-19 model

Increases of soluble urokinase plasminogen activator receptor (suPAR) were measured in both urine and plasma of a Chlorocebus aethiops (African green monkey; AGM) mucosal infected with SARS-CoV-2. The data indicate that elevated suPAR may be associated with renal dysfunction and pathology in the context of COVID-19.

Ophiopogonin D attenuates the progression of murine systemic lupus erythematosus by reducing B cell numbers

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by immune abnormalities leading to multi-organ damage. The activation of autoreactive B cell differentiation will lead to the production of pathogenic autoantibodies, contributing to the development of SLE. However, the effects of Ophiopogonin D (OP-D) on B cell activation and autoantibody production as well as renal injury in the pathogenesis of SLE remain unclear. MRL/lpr mice, one of the most commonly used animal models of SLE, were intragastrically administered with 5 mg/kg/d OP-D at 17 weeks of age for 3 weeks. The survival rates of mice in each group were monitored for 6 weeks until 23 weeks of age. Proteinuria and serum creatinine levels were measured. Serum levels of immunoglobulin (Ig)G, IgM, and anti-dsDNA autoantibodies were detected by enzyme-linked immunosorbent assay. Numbers of CD19⁺ B cells in the blood, spleen and bone marrow and numbers of splenic germinal center (GC) B cells were calculated by using flow cytometry. OP-D treatment prolonged survival in MRL/lpr mice. OP-D treatment reduced proteinuria and serum creatinine levels as well as mitigated renal pathological alternation in MRL/lpr mice. Furthermore, serum levels of IgG, IgM, and anti-dsDNA autoantibodies were reduced by OP-D treatment. OP-D lessened not only CD19⁺ B cells in the spleen and bone marrow but also plasma cells that secreted anti-dsDNA autoantibodies, IgG and IgM in the spleen and bone marrow. OP-D ameliorated the progression of SLE by inhibiting the secretion of autoantibodies though reducing B cell numbers.

Selected 2022 Highlights in Congenital Cardiac Anesthesia

This article is a review of the highlights of pertinent literature of interest to the congenital cardiac anesthesiologist, and was published in 2022. After a search of the United States National Library of Medicine PubMed database, several topics emerged in which significant contributions were made in 2022. The authors of this manuscript considered the following topics noteworthy to be included in this review-intensive care unit admission after congenital cardiac catheterization interventions, antifibrinolytics in pediatric cardiac surgery, the current status of the pediatric cardiac anesthesia workforce in the United States, and kidney injury and renal protection during congenital heart surgery.

[CD5L is elevated in the serum of patients with candidemia and promotes disease progression in mouse models]

OBJECTIVE

To investigate the changes of CD5L levels in patients with candidemia and explore the role of CD5L in progression of candidemia.

METHODS

Twenty healthy control individuals, 27 patients with bacteremia and 35 patients with candidemia were examined for serum CD5L levels using ELISA, and the correlations of CD5L level with other serological indicators were analyzed. A C57BL/6 mouse model of candidemia induced by intravenous injection of Candida albicans were treated with intraperitoneal injection of recombinant CD5L protein, and renal histopathological and serological changes were analyzed to assess renal injures. The effects of CD5L treatment on general condition, fungal burden, of survival of the mice were observed, and the changes in serum IL-6 and IL-8 levels of the mice were detected using ELISA.

RESULTS

CD5L levels were significantly elevated in patients with candidemia and positively correlated with WBC, BDG, Scr and PCT levels. The mouse model of candidemia also showed significantly increased serum and renal CD5L levels, and CD5L treatment significantly increased fungal burden in the renal tissue, elevated IL-6 and IL-8 levels in the serum and kidney, aggravated renal tissue damage, and reduced survival rate of candidemia mice.

CONCLUSION

Serum CD5L levels are increased in patients with candidemia, and treatment with CD5L aggravates candidemia in mouse models.

Modulatory Role of Autophagy in Metformin Therapeutic Activity toward Doxorubicin-Induced Nephrotoxicity

Doxorubicin (DOX) is a frequent chemotherapeutic drug used to treat various malignant tumors. One of the key factors that diminish its therapeutic importance is DOX-induced nephrotoxicity. The first-line oral antidiabetic drug is metformin (Met), which also has antioxidant properties. The purpose of our study was to investigate the underlying molecular mechanisms for the potential protective effects of Met on DOX-triggered nephrotoxicity. Four animal groups were assigned as follows; animals received vehicle (control group), 200 mg/kg Met (Met group), DOX 15 mg/kg DOX (DOX group), and a combination of DOX and Met (DOX/Met group). Our results demonstrated that DOX administration caused marked histological alterations of widespread inflammation and tubular degeneration. Notably, the DOX-induced dramatic up-regulation of the nuclear factor-kappa B/P65 (NF-κB/P65), microtubule-associated protein light chain 3B (LC3B), neutrophil gelatinase-associated lipocalin (NGAL), interleukin-1beta (IL-1β), 8-hydroxy-2' -deoxyguanosine (8-OHdG), and Beclin-1 in renal tissue. A marked increase in the malondialdehyde (MDA) tissue level and a decrease in the total antioxidant capacity (TAC) were also recorded in DOX-exposed animals. Interestingly, Met could minimize all histopathological changes as well as the disruptions caused by DOX in the aforementioned measures. Thus, Met provided a workable method for suppressing the nephrotoxicity that occurred during the DOX regimen via the deactivation of the Beclin-1/LC3B pathway.

TRPV4 functional status in cystic cells regulates cystogenesis in autosomal recessive polycystic kidney disease during variations in dietary potassium

Mechanosensitive TRPV4 channel plays a dominant role in maintaining [Ca2+ ]i homeostasis and flow-sensitive [Ca2+ ]i signaling in the renal tubule. Polycystic kidney disease (PKD) manifests as progressive cyst growth due to cAMP-dependent fluid secretion along with deficient mechanosensitivity and impaired TRPV4 activity. Here, we tested how regulation of renal TRPV4 function by dietary K+ intake modulates the rate of cystogenesis and mechanosensitive [Ca2+ ]i signaling in cystic cells of PCK453 rats, a homologous model of human autosomal recessive PKD (ARPKD). One month treatment with both high KCl (5% K+ ) and KB/C (5% K+ with bicarbonate/citrate) diets significantly increased TRPV4 levels when compared to control (0.9% K+ ). High KCl diet caused an increased TRPV4-dependent Ca2+ influx, and partial restoration of mechanosensitivity in freshly isolated monolayers of cystic cells. Unexpectedly, high KB/C diet induced an opposite effect by reducing TRPV4 activity and worsening [Ca2+ ]i homeostasis. Importantly, high KCl diet decreased cAMP, whereas high KB/C diet further increased cAMP levels in cystic cells (assessed as AQP2 distribution). At the systemic level, high KCl diet fed PCK453 rats had significantly lower kidney-to-bodyweight ratio and reduced cystic area. These beneficial effects were negated by a concomitant administration of an orally active TRPV4 antagonist, GSK2193874, resulting in greater kidney weight, accelerated cystogenesis, and augmented renal injury. High KB/C diet also exacerbated renal manifestations of ARPKD, consistent with deficient TRPV4 activity in cystic cells. Overall, we demonstrate that TRPV4 channel activity negatively regulates cAMP levels in cystic cells thus attenuating (high activity) or accelerating (low activity) ARPKD progression.

Efficacy and safety of pemafibrate in patients with chronic kidney disease: A retrospective study

Hypertriglyceridemia and chronic kidney disease (CKD) are known risk factors for cardiovascular disease. However, treatment with statins, which control low-density lipoprotein cholesterol levels, increases the risk of estimated glomerular filtration rate (eGFR) reduction. Although conventional fibrates, such as bezafibrate (Beza-F) and fenofibrate (Feno-F), are the mainstay for hypertriglyceridemia treatment, they may be associated with a risk of increased serum creatinine level and renal dysfunction. Pemafibrate (Pema) is pharmacologically defined as a selective peroxisomal proliferator-activated receptor α modulator which is excreted in bile and not likely to cause renal dysfunction. We evaluated the efficacy and safety of switching from Beza-F or Feno-F to Pema in CKD patients with hypertriglyceridemia. We recruited 47 CKD patients with hypertriglyceridemia who were receiving Beza-F, Feno-F, or eicosapentaenoic acid (EPA) but were switched to Pema from 2018 to 2021. A retrospective analysis of renal function and lipid profiles was performed before and 24 weeks after switching. CKD patients switching from EPA to Pema were used as study control. The effect of Pema on hypertriglyceridemia was equivalent to that of Beza-F or Feno-F. However, after switching to Pema, eGFR showed a marked average improvement of 10.2 mL/min/1.73 m2 (P < .001). Improvement in eGFR and levels of n-acetyl-β-d-glucosaminidase and β-2-microglobulin was observed only in cases of switching from Beza-F or Feno-F but not from EPA. Although Beza-F and Feno-F are useful medications for the treatment of hypertriglyceridemia, these are associated with a high risk of renal dysfunction. We also found that the deterioration in eGFR due to Beza-F or Feno-F is reversible with drug withdrawal and may not increase the risk for long-term renal dysfunction. We suggest that Pema may be an effective and safe treatment for hypertriglyceridemia in CKD patients.

Changes of antioxidant enzymes in the kidney after cardiac arrest in the rat model

Globally, cardiac arrest (CA) is a leading cause of death and disability. Asphyxial CA (ACA)-induced kidney damage is a crucial factor in reducing the survival rate. The purpose of this study was to investigate the role of antioxidant enzymes in histopathological renal damage in an ACA rat model at different time points. A total of 88 rats were divided into five groups and exposed to ACA except for the sham group. To evaluate glomerular function and oxidative stress, serum levels of blood urea nitrogen (BUN) and creatinine (Crtn) and malondialdehyde (MDA) levels in renal tissues were measured. To determine histopathological damage, hematoxylin and eosin staining, periodic acid-Schiff staining, and Masson's trichrome staining were performed. Expression levels of antioxidant enzymes including superoxide dismutase-1 (SOD-1), superoxide dismutase-2 (SOD-2), catalase (CAT), and glutathione peroxidase (GPx) were measured by immunohistochemistry (IHC). Survival rate of the experimental rats was reduced to 80% at 6 h, 55% at 12 h, 42.9% at 1 day, and 33% at 2 days after return of spontaneous circulation. Levels of BUN, Crtn, and MDA started to increase significantly in the early period of CA induction. Renal histopathological damage increased markedly from 6 h until two days post-CA. Additionally, expression levels of antioxidant enzymes were significantly decreased at 6 h, 12 h, 1 day, and 2 days after CA. CA-induced oxidative stress and decreased levels of antioxidant enzymes (SOD-1, SOD-2, CAT, GPx) from 6 h to two days could be possible mediators of severe renal tissue damage and increased mortality rate.

Succinate-SUCNR1 induces renal tubular cell apoptosis

Succinate has long been known to be only an intermediate product of the tricarboxylic acid cycle until identified as a natural ligand for SUCNR1 in 2004. SUCNR1 is widely expressed throughout the body, especially in the kidney. Abnormally elevated succinate is associated with many diseases, including obesity, type 2 diabetes, nonalcoholic fatty liver disease, and ischemia injury, but it is not known whether succinate can cause kidney damage. This study showed that succinate induced apparent renal injury after treatment for 12 wk, characterized by a reduction in 24 h urine and the significant detachment of the brush border of proximal tubular epithelial cells, tubular dilation, cast formation, and vacuolar degeneration of tubular cells in succinate-treated mice. Besides, succinate caused tubular epithelial cell apoptosis in kidneys and HK-2 cells. Mechanistically, succinate triggered cell apoptosis via SUCNR1 activation. In addition, succinate upregulated ERK by binding to SUCNR1, and inhibition of ERK using PD98059 abolished the proapoptotic effects of succinate in HK-2 cells. In summary, our study provides the first evidence that succinate acts as a risk factor and contributes to renal injury, and further research is required to discern the pathological effects of succinate on renal functions.

Glycyrrhizic acid improves tacrolimus-induced renal injury by regulating autophagy

Tacrolimus (TAC)-induced renal injury is detrimental to long-term kidney function, but a treatment medication is not available. Glycyrrhizic acid (GA) is an active ingredient in licorice widely used to treat kidney disease. Thus, this study explored the mechanisms of renoprotection by GA on TAC-induced renal injury. C57BL/6 mice were subjected daily to TAC or a combination of TAC and GA for 4 weeks, and then renal function, histopathology, and autophagy were assessed to examine the effect of GA on a renal injury. Next, Human kidney proximal tubular epithelial (HK-2) cells were pretreated with GA for 2 h and then treated with TAC for 24 h. The effect of GA on TAC-induced HK-2 cell injury was assessed by measuring cell viability, apoptosis, autophagy, and lysosomes. Mice exposed to TAC and treated with GA had significantly greater improvements in renal function and tubulointerstitial fibrosis in comparison to mice not treated with GA. In addition, fibrosis-related protein expression, including α-smooth muscle actin and fibronectin, decreased after GA treatment. GA treatment also relieved autophagic clearance in TAC-induced renal injury. Several in vitro studies found that TAC inhibited cell viability, autophagy, lysosomal acidification, and promoted apoptosis. However, these results were less pronounced with GA pretreatment. In addition, bafilomycin A1 (which inhibits lysosomal function) reduced the protective effect of GA, indicating that lysosomal function plays an important role in this effect. Our data suggest that GA improves lysosomal function and regulates autophagy to protect against TAC-induced renal injury.

Renoprotective Effect of Taxifolin in Paracetamol-Induced Nephrotoxicity: Emerging Evidence from an Animal Model

BACKGROUND

Taxifolin (TXF) is a flavonoid found abundantly in citrus/onion. Encouraging results on its renoprotective effect have been reported in a limited number of drug-induced nephrotoxicity animal models. The present study aimed to evaluate for the first time the potential renoprotective effects of TXF in a paracetamol (PAR)-induced nephrotoxicity rat model.

METHODS

Rats were divided into three equal groups (n = 6 animals per group). Group 1 (PAR group, PARG) received PAR diluted in normal saline by gavage (1000 mg/kg). Group 2 (TXF group, TXFG) received TXF diluted in normal saline by gavage (50 mg/kg) one hour after PAR administration. Group 3 (control group, CG) received normal saline. Twenty-four hours after PAR administration, all animals were sacrificed using high-dose anesthesia. Blood samples were collected and kidneys were removed.

RESULTS

The serum blood urea nitrogen, creatinine levels and serum malondialdehyde levels were significantly increased in the PARG. The serum glutathione peroxidase, glutathione reductase and total glutathione levels were significantly higher in the TXFG. At the same time, the kidneys of the PARG animals demonstrated tubular epithelium swelling, distension and severe vacuolar degeneration. The kidneys of the TXFG animals showed mildly dilated/congested blood vessels.

CONCLUSIONS

The TXF renoprotective effects are promising in preventing PAR-induced nephrotoxicity, mainly through antioxidant activity, and warrant further testing in future studies.

Lycopene Attenuates Di(2-ethylhexyl) Phthalate-Induced Mitochondrial Damage and Inflammation in Kidney via cGAS-STING Signaling

Di(2-ethylhexyl) phthalate (DEHP) is a highly harmful and persistent environmental pollutant. Due to its unique chemical composition, it frequently dissolves and enters the environment to endanger human and animal health. Lycopene is a natural bioactive component that can potentially reduce the risk of environmental factor-induced chronic diseases. The present study sought to explore the role and underlying mechanism of lycopene (LYC) on DEHP-induced renal inflammatory response and apoptosis. In this study, mice were orally treated with LYC (5 mg/kg BW/day) and/or DEHP (500 or 1000 mg/kg BW/day) for 28 days. Our results indicated that LYC prevented DEHP-induced histopathological alterations and ultrastructural injuries, including decreased mitochondrial membrane potential (ΔΨm), PINK1/Parkin pathway-mediated mitophagy, and mitochondrial energetic deficit. When damaged mitochondria release mitochondrial DNA (mtDNA) into cytosol, LYC can alleviate inflammation and apoptosis caused by DEHP exposure by activating the cyclic GMP-AMP synthase-stimulator of interferon gene (cGAS-STING) signal pathway. Collectively, our data demonstrate that LYC can reduce mitophagy caused by DEHP exposure by activating the PINK1/Parkin pathway and then reduce renal inflammation and apoptosis through the cGAS-STING pathway.

Amelioration of Cyclosporine A-Induced Acute Nephrotoxicity by Cordyceps cicadae Mycelia via Mg+2 Reabsorption and the Inhibition of GRP78-IRE1-CHOP Pathway: In Vivo and In Vitro

Fruiting bodies of Cordyceps cicadae (CC) have been reported to have a therapeutic effect in chronic kidney disease. Due to the rare and expensive resources from natural habitats, artificially cultivated mycelia using submerged liquid cultivation of CC (CCM) have been recently developed as an alternative to scarce sources of CC. However, little is known regarding potential protective effects of CCM against cyclosporine A (CsA)-induced acute nephrotoxicity in vivo and in vitro. In this study, male Sprague-Dawley rats were divided into six groups: control, CCM (40 mg and 400 mg/kg, orally), CsA (10 mg/kg, oral gavage), and CsA + CCM (40 mg and 400 mg/kg, orally). At the end of the study on day 8, all rats were sacrificed, and the blood and kidneys retrieved. CsA-induced acute nephrotoxicity was evident by increased levels of blood urea nitrogen (BUN). Levels of the endoplasmic reticulum (ER) resident chaperone glucose regulated protein 78 (GRP 78) were increased significantly in rats with acute nephrotoxicity. BUN and GRP 78 were significantly ameliorated in synchronous oral groups of CCM (40 or 400 mg/kg) plus CsA. Examination of hematoxylin and eosin stained kidney tissues revealed that the combined treatment of CCM slightly improved vacuolization in renal tubules upon CsA-induced damage. CsA-induced down-regulation of protein expression of magnesium ion channel proteins and transient receptor potential melastatin 6 and 7 were abolished by the combined treatment of CCM. CCM has the potential to protect the kidney against CsA-induced nephrotoxicity by reducing magnesium ion wasting, tubular cell damage, and ER stress demonstrated further by human renal proximal tubular epithelial cell line HK-2. Our results contribute to the in-depth understanding of the role of polysaccharides and nucleobases as the main secondary metabolites of CCM in the defense system of renal functions in CsA-induced acute nephrotoxicity.

Intraoperative Urine Oxygen in Cardiac Surgery and 12-Month Outcomes

Low intraoperative urinary oxygen during cardiac surgery is associated with increased risk of poor 12-month outcomes. With decreasing urinary oxygen thresholds, the risk of poor 12-month outcomes increases.

Identification of new immune subtypes of renal injury associated with anti-neutrophil cytoplasmic antibody-associated vasculitis based on integrated bioinformatics analysis

Background: Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a systemic autoimmune disease that may lead to end-stage renal disease. However, few specifific biomarkers are available for AAV-related renal injury. The aim of this study was to identify important biomarkers and explore new immune subtypes of AAV-related renal injury. Methods: In this study, messenger RNA expression profiles for antibody-associated vasculitis and AAV-associated kidney injury were downloaded from the Gene Expression Omnibus database. Weighted gene co-expression network analysis (WGCNA) was performed to identify the most relevant module genes to AAV. Key module genes from WGCNA were then intersected with AAV- and nephropathy-related genes from the Genecards database to identify key genes for AAV-associated kidney injury. Subsequently, the expression of key genes was validated in independent datasets and the correlation of genes with clinical traits of kidney injury was verified by the Nephroseq database. Finally, non-negative matrix factorization (NMF) clustering was performed to identify the immune subtypes associated with the key genes. Results: Eight co-key genes (AGTR2, ANPTL2, BDKRB1, CSF2, FGA, IL1RAPL2, PCDH11Y, and PGR) were identifified, and validated the expression levels independent datasets. Receiver operating characteristic curve analysis revealed that these eight genes have major diagnostic value as potential biomarkers of AAV-related renal injury. Through our comprehensive gene enrichment analyses, we found that they are associated with immune-related pathways. NMF clustering of key genes identified two and three immune-related molecular subtypes in the glomerular and tubular data, respectively. A correlation analysis with prognostic data from the Nephroseq database indicated that the expression of co-key genes was positively co-related with the glomerular filtration rate. Discussion: Altogether, we identifified 8 valuable biomarkers that firmly correlate with the diagnosis and prognosis of AAV-related renal injury. These markers may help identify new immune subtypes for AAV-related renal injury.