Acute kidney injury and chronic kidney disease as interconnected syndromes

Multifunctional Nanosystem Based on Ultrasmall Carbon Dots for the Treatment of Acute Kidney Injury

Acute kidney injury (AKI) is a critical medical condition characterized by high morbidity and mortality rates. The pathogenesis of AKI potentially involves bursts of reactive oxygen species (ROS) bursts and elevated levels of inflammatory mediators. Developing nanoparticles (NPs) that downregulate ROS and inflammatory mediators is a promising approach to treat AKI. However, such NPs would be affected by the glomerular filtration barrier (GFB). Typically, NPs are too large to penetrate the glomerular system and reach the renal tubules─the primary site of AKI injury. Herein, we report the development of ultrasmall carbon dots-gallic acid (CDs-GA) NPs (∼5 nm). These NPs exhibited outstanding biocompatibility and were shown not only to efficiently eliminate ROS and alleviate oxidative stress but also to suppress the activation of the NF-κB signaling pathway, leading to a reduction in the release of inflammatory factors. Importantly, CDs-GA NPs were shown to be able to rapidly accumulate rapidly in the renal tissues without the need for intricate targeting strategies. In vivo studies demonstrated that CDs-GA NPs significantly reduced the incidence of cisplatin (CDDP)-induced AKI in mice, surpassing the efficacy of the small molecular drug, N-acetylcysteine. This research provides an innovative strategy for the treatment of AKI.

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

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

Epigenetic reprogramming driving successful and failed repair in acute kidney injury

Acute kidney injury (AKI) causes epithelial damage followed by subsequent repair. While successful repair restores kidney function, this process is often incomplete and can lead to chronic kidney disease (CKD) in a process called failed repair. To better understand the epigenetic reprogramming driving this AKI-to-CKD transition, we generated a single-nucleus multiomic atlas for the full mouse AKI time course, consisting of ~280,000 single-nucleus transcriptomes and epigenomes. We reveal cell-specific dynamic alterations in gene regulatory landscapes reflecting, especially, activation of proinflammatory pathways. We further generated single-nucleus multiomic data from four human AKI samples including validation by genome-wide identification of nuclear factor κB binding sites. A regularized regression analysis identifies key regulators involved in both successful and failed repair cell fate, identifying the transcription factor CREB5 as a regulator of both successful and failed tubular repair that also drives proximal tubular cell proliferation after injury. Our interspecies multiomic approach provides a foundation to comprehensively understand cell states in AKI.

Persistent acute kidney injury biomarkers: A systematic review and meta-analysis

BACKGROUND

Various biomarkers reportedly predict persistent acute kidney injury (AKI) despite their varying predictive performance across clinical trials. This study aims to compare the accuracy of various biomarkers in predicting persistent AKI in different populations and regions.

METHODS

In this meta-analysis, we searched for urinary C-C motif chemokine ligand 14 (CCL14), Tissue inhibitor of metalloproteinase-2&insulin-like growth factor-binding protein-7 (TIMP-2&IGFBP7), Neutrophil Gelatinase-Associated Lipocalin (NGAL), plasma Cystatin C (pCysC), Soluble urokinase plasminogen activator receptor (suPAR), Proenkephalin (PenK) and urinary dickkopf-3:urinary creatinine (uDKK3:uCr) from various databases including Medline, PubMed, Embase, and Cochrane. This was geared towards predicting persistent AKI in adults (>18 years). Hierarchically summarized subject work characteristic curves (HSROC) and diagnostic odds ratio (DOR) values were used to summarize the diagnostic accuracy of the biomarkers. Further, meta-regression and subgroup analyses were carried out to identify sources of heterogeneity as well as evaluate the best predictive biomarkers in different populations and regions.

RESULTS

We screened 31 studies from 2,356 studies and assessed the diagnostic value of 7 biomarkers for persistent AKI. Overall, CCL14 had the best diagnostic efficacy with an AUC of 0.79 (95% CI 0.75-0.82), whereas TIMP-2 & IGFBP7, NGAL, and pCysC had diagnostic efficacy of 0.75 (95% CI 0.71-0.79), 0.71 (95% CI 0.67-0.75), and 0.7007, respectively. Due to a limited number of studies, PenK, uDKK3:uCr, and suPAR were not subjected to meta-analysis; however, relevant literature reported diagnostic efficacy above 0.70. Subgroup analyses based on population, region, biomarker detection time, AKI onset time, and AKI duration revealed that in the intensive care unit (ICU) population, the AUC of CCL14 was 0.8070, the AUC of TIMP-2 & IGFBP7 was 0.726, the AUC of pCysC was 0.72, and the AUC of NGAL was 0.7344; in the sepsis population, the AUC of CCL14 was 0.85, the AUC of TIMP-2&IGFBP7 was 0.7438, and the AUC of NGAL was 0.544; in the post-operative population, the AUC of CCL14 was 0.83-0.93, the AUC of TIMP-2&IGFBP7 was 0.71, and the AUC of pCysC was 0.683. Regional differences were observed in biomarker prediction of persistent kidney injury, with AUCs of 0.8558 for CCL14, 0.7563 for TIMP-2 & IGFBP7, and 0.7116 for NGAL in the Eurasian American population. In the sub-African population, TIMP-2 & IGFBP7 had AUCs of 0.7945, 0.7418 for CCL14, 0.7097 for NGAL, and 0.7007 for pCysC. for TIMP-2 & IGFBP7 was 0.7945, AUC for CCL14 was 0.7418, AUC for NGAL was 0.7097, and AUC for pCysC was 0.7007 in the sub-African population. Duration of biomarker detection, AKI onset, and AKI did not influence the optimal predictive performance of CCL14. Subgroup analysis and meta-regression of CCL14-related studies revealed that CCL14 is the most appropriate biomarker for predicting persistent stage 2-3 AKI, with heterogeneity stemming from sample size and AKI staging.

CONCLUSION

This meta-analysis discovered CCL14 as the best biomarker to predict persistent AKI, specifically persistent stage 2-3 AKI.

Lymphocytes and innate immune cells in acute kidney injury and repair

Acute kidney injury (AKI) is a common and serious disease entity that affects native kidneys and allografts but for which no specific treatments exist. Complex intrarenal inflammatory processes driven by lymphocytes and innate immune cells have key roles in the development and progression of AKI. Many studies have focused on prevention of early injury in AKI. However, most patients with AKI present after injury is already established. Increasing research is therefore focusing on mechanisms of renal repair following AKI and prevention of progression from AKI to chronic kidney disease. CD4+ and CD8+ T cells, B cells and neutrophils are probably involved in the development and progression of AKI, whereas regulatory T cells, double-negative T cells and type 2 innate lymphoid cells have protective roles. Several immune cells, such as macrophages and natural killer T cells, can have both deleterious and protective effects, depending on their subtype and/or the stage of AKI. The immune system not only participates in injury and repair processes during AKI but also has a role in mediating AKI-induced distant organ dysfunction. Targeted manipulation of immune cells is a promising therapeutic strategy to improve AKI outcomes.

Biomarkers of acute kidney injury: From discovery to the future of clinical practice

Purpose of this review Acute kidney injury (AKI) is a complex syndrome whose development is associated with an increased morbidity and mortality. Recent studies show that this syndrome is a common complication in critically ill and surgical patients the trajectory of which may differ. As AKI can be induced by different triggers, it is complex and therefore challenging to manage patients with AKI. This review strives to provide a brief historical perspective on AKI, elucidate recent developments in diagnosing and managing AKI, and show the current usage of novel biomarkers in both clinical routine and research. In addition, we provide a perspective on potential future developments and their impact of AKI understanding and management. Recent findings/developments Recent studies show the merits of stress and damage biomarkers, highlighting limitations of the current KDIGO definition that only uses the functional biomarkers serum creatinine and urine output. The use of novel biomarkers led to the introduction of the concept of "subclinical AKI". This new classification may allow a more distinct management of affected or at risk patients. Ongoing studies, such as BigpAK-2 and PrevProgAKI, investigate the implementation of biomarker-guided interventions in clinical practice and may demonstrate an improvement in patients' outcome. Summary The ongoing scientific efforts surrounding AKI have deepened our understanding of the syndrome prompting an expansion of existing concepts. A future integration of stress and damage biomarkers in AKI management, may lead to an individualized therapy in this area.

Genome-wide association study of hospitalized patients and acute kidney injury

Acute kidney injury (AKI) is a common and devastating complication of hospitalization. Here, we identified genetic loci associated with AKI in patients hospitalized between 2002-2019 in the Million Veteran Program and data from Vanderbilt University Medical Center's BioVU. AKI was defined as meeting a modified KDIGO Stage 1 or more for two or more consecutive days or kidney replacement therapy. Control individuals were required to have one or more qualifying hospitalizations without AKI and no evidence of AKI during any other observed hospitalizations. Genome-wide association studies (GWAS), stratified by race, adjusting for sex, age, baseline estimated glomerular filtration rate (eGFR), and the top ten principal components of ancestry were conducted. Results were meta-analyzed using fixed effects models. In total, there were 54,488 patients with AKI and 138,051 non-AKI individuals included in the study. Two novel loci reached genome-wide significance in the meta-analysis: rs11642015 near the FTO locus on chromosome 16 (obesity traits) (odds ratio 1.07 (95% confidence interval, 1.05-1.09)) and rs4859682 near the SHROOM3 locus on chromosome 4 (glomerular filtration barrier integrity) (odds ratio 0.95 (95% confidence interval, 0.93-0.96)). These loci colocalized with previous studies of kidney function, and genetic correlation indicated significant shared genetic architecture between AKI and eGFR. Notably, the association at the FTO locus was attenuated after adjustment for BMI and diabetes, suggesting that this association may be partially driven by obesity. Both FTO and the SHROOM3 loci showed nominal evidence of replication from diagnostic-code-based summary statistics from UK Biobank, FinnGen, and Biobank Japan. Thus, our large GWA meta-analysis found two loci significantly associated with AKI suggesting genetics may explain some risk for AKI.

Engineering Cyanine- and Hemicyanine-Based Probes for Optical Imaging of Kidney Diseases

Molecular optical probes play pivotal roles in in vivo imaging of biomarkers associated to kidney diseases. Relying on structural tunability and high fluorescence quantum yields, versatile optical probes have been constructed on cyanine or hemicyanine-based scaffold in recent years. This review summaries the recent progress on the development of optical probes for imaging of kidney diseases, particularly through near-infrared fluorescence, chemiluminescence and photoacoustic imaging modalities. The chemical design and sensing mechanisms are discussed along with applications in the detection of renal cell carcinoma and acute kidney injury. This progress provides insights and directions for the development of next generation kidney-targeted probes and for pushing their further applications in preclinical and clinical research.

Non-steroidal anti-inflammatory drugs, renin-angiotensin system blockade or diuretics and risk of acute kidney injury: A case-crossover study

BACKGROUND

Aging-related physiological changes, such as decline in renal function, not only exacerbates pre-existing comorbidities but also escalate the susceptibility to adverse events. Previous studies have shown that non-steroidal anti-inflammatory drugs (NSAIDs) are associated with an increased risk of acute kidney injury (AKI), and the concomitant use of renin-angiotensin system blockade or diuretics may further potentiate the risk. However, studies evaluating the risk of AKI associated with NSAIDs (including routes, concomitant use of different NSAIDs, categories (traditional NSAIDs or COX-2 inhibitors), and cumulative doses of NSAIDs) are limited, particularly the risk of AKI associated with the dual or triple combination of NSAIDs with renin-angiotensin system blockade (RAS blockades) and/or diuretics.

METHODS

A case-crossover study utilized two sets of longitudinal data from Taiwan's National Health Insurance Research Database (NHIRD). Newly admitted patients with a primary AKI diagnosis were included, with the index date defined as the first admission date. The 1-7 days and 181-187 days prior to the index date served as the case and control periods. Exposure to NSAIDs and co-exposures of RAS blockade and/or diuretics were assessed in both periods. Multivariable conditional logistic regression models, adjusting for potential confounders, estimated adjusted odds ratios (aORs) and 95 % confidence intervals (CIs) for AKI associated with NSAIDs, dual, or triple combinations. Sensitivity analyses explored result robustness by varying case and control period lengths.

RESULTS

The study included 1,284 newly diagnosed AKI patients. NSAIDs showed a 3.55-fold increased risk of AKI (aOR: 3.55; 95 % CI 2.70-4.65), with similar risks for traditional NSAIDs and COX-2 inhibitors. Use of multiple NSAIDs, parenteral dosage forms, and higher cumulative doses increased AKI risk. Dual combination with either RAS blockade or diuretics resulted in a 2.90-fold (aOR: 2.90; 95 %CI 1.47-5.70) and 12.68-fold (aOR: 12.68; 95 %CI 6.15-26.12) risk, respectively. The highest risk occurred with triple combination (aOR: 29.22; 95 %CI 12.82-66.64).

CONCLUSIONS

NSAIDs, including both non-selective NSAIDs and COX2 inhibitors, elevate the risk of AKI. Increased AKI risk is linked to using multiple NSAIDs, the parenteral dosage form, and higher cumulative doses. Dual combination of RAS blockade with NSAIDs or diuretics with NSAIDs, as well as triple therapy, heightens the risk, with the latter associated with the highest risk of AKI.

Impact of spinal or epidural anaesthesia on perioperative outcomes in adult noncardiac surgery: a narrative review of recent evidence

Spinal and epidural anaesthesia and analgesia are important anaesthetic techniques, familiar to all anaesthetists and applied to patients undergoing a range of surgical procedures. Although the immediate effects of a well-conducted neuraxial technique on nociceptive and sympathetic pathways are readily observable in clinical practice, the impact of such techniques on patient-centred perioperative outcomes remains an area of uncertainty and active research. The aim of this review is to present a narrative synthesis of contemporary clinical science on this topic from the most recent 5-year period and summarise the foundational scholarship upon which this research was based. We searched electronic databases for primary research, secondary research, opinion pieces, and guidelines reporting the relationship between neuraxial procedures and standardised perioperative outcomes over the period 2018-2023. Returned citation lists were examined seeking additional studies to contextualise our narrative synthesis of results. Articles were retrieved encompassing the following outcome domains: patient comfort, renal, sepsis and infection, postoperative cancer, cardiovascular, and pulmonary and mortality outcomes. Convincing evidence of the beneficial effect of epidural analgesia on patient comfort after major open thoracoabdominal surgery outcomes was identified. Recent evidence of benefit in the prevention of pulmonary complications and mortality was identified. Despite mechanistic plausibility and supportive observational evidence, there is less certain experimental evidence to support a role for neuraxial techniques impacting on other outcome domains. Evidence of positive impact of neuraxial techniques is best established for the domains of patient comfort, pulmonary complications, and mortality, particularly in the setting of major open thoracoabdominal surgery. Recent evidence does not strongly support a significant impact of neuraxial techniques on cancer, renal, infection, or cardiovascular outcomes after noncardiac surgery in most patient groups.

Renal Complications in Portal Hypertension

Acute kidney injury (AKI) is a common complication among patients with decompensated cirrhosis and its development is associated with worse prognosis in terms of survival. Patients with decompensated cirrhosis may develop a unique type of AKI, known as hepatorenal syndrome (HRS-AKI), characterized by marked impairment of kidney function due to haemodynamic changes that occur in late stages of liver cirrhosis. Besides, patients with cirrhosis also may develop chronic alterations of kidney function (chronic kidney disease, CKD), the incidence of which is increasing markedly and may be associated with clinical complications. The aim of this review is to provide the reader with an update of the most relevant aspects of alterations of kidney function in patients with cirrhossi that may be useful for theri clinical practice.

Evaluating the incidence and risk factors for developing acute tubular necrosis after percutaneous coronary intervention in the management of coronary artery dissection

BACKGROUND

Coronary artery dissection is managed primarily conservatively with serial imaging or percutaneous coronary intervention (PCI). Exposure to contrast in either modality could potentially result in acute tubular necrosis (ATN). However, no data compares ATN incidence in these management strategies. This study compares the incidence of ATN and associated mortality of PCI and conservative management of coronary artery dissection.

METHODS

A retrospective analysis was performed using data from the National Inpatient Sample database, including patients with coronary artery dissection between 2016 through 2020. We analyzed the incidence of ATN and associated mortality of PCI and conservative management of coronary artery dissection.

RESULTS

We found that the odds of developing ATN were 22% lower in patients managed with PCI than those managed conservatively. There was no difference in the in-hospital mortality or hospital length of stay between the two groups but the mortality rate in patients with ATN was double that of those who did not develop ATN in both PCI and conservatively managed groups.

CONCLUSIONS

The higher incidents of ATN in patients with coronary dissection being managed with conservative measures compared to PCI suggest that the use of CTA may be harmful. Additionally, persons who developed ATN may have higher mortality. Therefore, more studies in the management of coronary artery dissection need to be done which would allow further steps to be taken to reduce this harm.

Nephron-Specific Lin28A Overexpression Triggers Severe Inflammatory Response and Kidney Damage

The RNA-binding proteins LIN28A and LIN28B contribute to a variety of developmental biological processes. Dysregulation of Lin28A and Lin28B expression is associated with numerous types of tumors. This study demonstrates that Lin28A overexpression in the mouse nephrons leads to severe inflammation and kidney damage rather than to tumorigenesis. Notably, Lin28A overexpression causes inflammation only when expressed in nephrons, but not in the stromal cells of the kidneys, highlighting its cell context-dependent nature. The nephron-specific Lin28A-induced inflammatory response differs from previously described Lin28B-mediated inflammatory feedback loops as it is IL-6 independent. Instead, it is associated with the rapid upregulation of cytokines like Cxcl1 and Ccl2. These findings suggest that the pathophysiological effects of Lin28A overexpression extend beyond cell transformation. Our transgenic mouse model offers a valuable tool for advancing our understanding of the pathophysiology of acute kidney injury, where inflammation is a key factor.

Renoprotective effects of apocynin and/or umbelliferone against acrylamide-induced acute kidney injury in rats: role of the NLRP3 inflammasome and Nrf-2/HO-1 signaling pathways

Acrylamide (ACR) is a toxic, probably carcinogenic compound commonly found in fried foods and used in the production of many industrial consumer products. ACR-induced acute kidney injury is mediated through several signals. In this research, we investigated, for the first time, the therapeutic effects of phytochemicals apocynin (APO) and/or umbelliferone (UMB) against ACR-induced nephrotoxicity in rats and emphasized the underlying molecular mechanism. To achieve this goal, five groups of rats were randomly assigned: the control group received vehicle (0.5% CMC; 1 ml/rat), ACR (40 mg/kg, i.p.), ACR + APO (100 mg/kg, P.O.), ACR + UMB (50 mg/kg, P.O.), and combination group for 10 days. In ACR-intoxicated rats, there was a significant reduction in weight gain while the levels of blood urea, uric acid, creatinine, and Kim-1 were elevated, indicating renal injury. Histopathological injury was also observed in the kidneys of ACR-intoxicated rats, confirming the biochemical data. Moreover, MDA, TNF-α, and IL-1β levels were raised; and GSH and SOD levels were decreased. In contrast, treatment with APO, UMB, and their combination significantly reduced the kidney function biomarkers, prevented tissue damage, and decreased inflammatory cytokines and MDA. Mechanistically, it suppressed the expression of NLRP-3, ASC, GSDMD, caspase-1, and IL-1β, while it upregulated Nrf-2 and HO-1 in the kidneys of ACR-intoxicated rats. In conclusion, APO, UMB, and their combination prevented ACR-induced nephrotoxicity in rats by attenuating oxidative injury and inflammation, suppressing NLRP-3 inflammasome signaling, enhancing antioxidants, and upregulating Nrf-2 and HO-1 in the kidneys of ACR-induced rats.

The Relationship between Selective Digestive Decontamination and Nosocomial Infections in Patients Receiving Continuous Renal Replacement Therapy in ICUs: A Multicenter Study

Background: Nosocomial infections are a worldwide healthcare issue, especially in intensive care units (ICUs), and they had a prevalence of 21.1% in 2023 in Spain. Numerous predisposing risk factors have been identified, with the most relevant being invasive techniques, including renal replacement therapies (RRTs). Several outstanding strategies have been published that prevent or reduce their incidence, including the nationwide ZERO in Spain, which consists of structured guidelines to be implemented to tackle this problem. One of these strategies, which is defined as 'highly recommended' in these projects, is selective digestive decontamination (SDD). The main aim of this study is to compare the incidences of ICU-acquired infections, including those due to multidrug-resistant bacteria (MDRB), in two cohorts of RRT with or without SDD. Methods: We conducted a multicenter, prospective, observational study at two tertiary hospitals in Spain. In total, 140 patients treated with RRT were recruited based on their exposure to SDD. Surveillance microbiological samples and nosocomial infection risk factors were obtained. Infection rates per 1000 days of exposure and the MDRB incidence density ratio were determined. Results: SDD statistically significantly reduced RRT-associated nosocomial infections (OR: 0.10, 95% CI: (0.04-0.26)) and the MDRB incidence density ratio (IDR: 0.156, 95% CI = 0.048-0.506). However, mechanical ventilation (OR: 7.91, 95% CI: (2.54-24.66)) and peripheral vascular disease (OR: 3.17, 95% CI: (1.33-7.56)) were significantly associated with increases in infections. Conclusions: Our results favor the use of SDD in ICU patients with renal failure undergoing CRRT as a tool for infection control.

The novel potential therapeutic target PSMP/MSMP promotes acute kidney injury via CCR2

Acute kidney injury (AKI) is a major worldwide health concern that currently lacks effective medical treatments. PSMP is a damage-induced chemotactic cytokine that acts as a ligand of CCR2 and has an unknown role in AKI. We have observed a significant increase in PSMP levels in the renal tissue, urine, and plasma of patients with AKI. PSMP deficiency improved kidney function and decreased tubular damage and inflammation in AKI mouse models induced by kidney ischemia-reperfusion injury, glycerol, and cisplatin. Single-cell RNA sequencing analysis revealed that Ly6Chi or F4/80lo infiltrated macrophages (IMs) were a major group of proinflammatory macrophages with strong CCR2 expression in AKI. We observed that PSMP deficiency decreased CCR2+Ly6Chi or F4/80lo IMs and inhibited M1 polarization in the AKI mouse model. Moreover, overexpressed human PSMP in the mouse kidney could reverse the attenuation of kidney injury in a CCR2-dependent manner, and this effect could be achieved without CCL2 involvement. Extracellular PSMP played a crucial role, and treatment with a PSMP-neutralizing antibody significantly reduced kidney injury in vivo. Therefore, PSMP might be a therapeutic target for AKI, and its antibody is a promising therapeutic drug for the treatment of AKI.

Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Heterogeneity in the definition of major adverse kidney events: a scoping review

Acute kidney injury (AKI) is associated with persistent renal dysfunction, the receipt of dialysis, dialysis dependence, and mortality. Accordingly, the concept of major adverse kidney events (MAKE) has been adopted as an endpoint for assessing the impact of AKI. However, applied criteria or observation periods for operationalizing MAKE appear to vary across studies. To evaluate this heterogeneity for MAKE evaluation, we performed a systematic scoping review of studies that employed MAKE as an AKI endpoint. Four major academic databases were searched, and we identified 122 studies with increasing numbers over time. We found marked heterogeneity in applied criteria and observation periods for MAKE across these studies, with some even lacking a description of criteria. Moreover, 13 different observation periods were employed, with 30 days and 90 days as the most common. Persistent renal dysfunction was evaluated by estimated glomerular filtration rate (34%) or serum creatinine concentration (48%); however, 37 different definitions for this component were employed in terms of parameters, cut-off criteria, and assessment periods. The definition for the dialysis component also showed significant heterogeneity regarding assessment periods and duration of dialysis requirement (chronic vs temporary). Finally, MAKE rates could vary by 7% [interquartile range: 1.7-16.7%] with different observation periods or by 36.4% with different dialysis component definitions. Our findings revealed marked heterogeneity in MAKE definitions, particularly regarding component assessment and observation periods. Dedicated discussion is needed to establish uniform and acceptable standards to operationalize MAKE in terms of selection and applied criteria of components, observation period, and reporting criteria for future trials on AKI and related conditions.

Ultrasmall Polyphenol-NAD+ Nanoparticle-Mediated Renal Delivery for Mitochondrial Repair and Anti-Inflammatory Treatment of AKI-to-CKD Progression

As a central metabolic molecule, nicotinamide adenine dinucleotide (NAD+) can potentially treat acute kidney injury (AKI) and chronic kidney disease (CKD); however, its bioavailability is poor due to short half-life, instability, the deficiency of targeting, and difficulties in transmembrane transport. Here a physiologically adaptive gallic acid-NAD+ nanoparticle is designed, which has ultrasmall size and pH-responsiveness, passes through the glomerular filtration membrane to reach injured renal tubules, and efficiently delivers NAD+ into the kidneys. With an effective accumulation in the kidneys, it restores renal function, immune microenvironment homeostasis, and mitochondrial homeostasis of AKI mice via the NAD+-Sirtuin-1 axis, and exerts strong antifibrotic effects on the AKI-to-CKD transition by inhibiting TGF-β signaling. It also exhibits excellent stability, biodegradable, and biocompatible properties, ensuring its long-term safety, practicality, and clinical translational feasibility. The present study shows a potential modality of mitochondrial repair and immunomodulation through nanoagents for the efficient and safe treatment of AKI and CKD.

Hyperuricemia - consequences of not initiating therapy. Benefits and drawbacks of treatment

Hyperuricemia, characterized by elevated levels of uric acid in the body, is associated with several health risks, including gout, urolithiasis and cardiovascular disease. Although treatment options are available, they can lead to hypersensitivity reactions, particularly with allopurinol therapy. This paper provides a comprehensive review of the consequences of hyperuricemia, the need for treatment and the potential adverse effects of allopurinol, illustrated by a case study. The study highlights the importance of careful consideration before initiating therapy, particularly in patients with comorbidities and concomitant medication. It emphasizes the need for vigilant monitoring and individualized treatment approaches to reduce adverse effects. In addition, genetic factors, particularly HLA-B*5801, play an important role in determining susceptibility to allopurinol hypersensitivity reactions. This paper highlights the importance of informed decision making in the management of hyperuricemia to optimize patient outcomes while minimizing the risks associated with treatment.

The correlation between serum angiopoietin-2 levels and acute kidney injury (AKI): a meta-analysis

INTRODUCTION

The correlation between serum angiopoietin-2 levels and acute kidney injury (AKI) is a topic of significant clinical interest. This meta-analysis aims to provide a comprehensive evaluation of this relationship.

CONTENT

A systematic search was conducted in PubMed, Embase, Web of Science, and Cochrane databases up to October 11, 2023. The included studies were evaluated using the Newcastle-Ottawa Scale (NOS) and Methodological Index for Non-Randomized Studies (MINORS). Weighted mean differences (WMD) and odds ratios (OR) were calculated using random-effects models. Sensitivity analysis, funnel plots, and Egger's test were used to assess the robustness and publication bias of the findings. Subgroup analyses were performed to explore potential variations between adults and children.

SUMMARY

Eighteen studies encompassing a total of 7,453 participants were included. The analysis revealed a significant elevation in serum angiopoietin-2 levels in patients with AKI compared to those without (WMD: 4.85; 95 % CI: 0.75 to 0.27; I²=93.2 %, p<0.001). Subgroup analysis indicated significantly higher angiopoietin-2 levels in adults with AKI (WMD: 5.17; 95 % CI: 3.51 to 6.83; I²=82.6 %, p<0.001), but not in children. Additionally, high serum angiopoietin-2 levels were associated with an increased risk of AKI (OR: 1.58; 95 % CI: 1.39 to 1.8; I²=89.1 %, p<0.001). Sensitivity analysis validated the robustness of these results, showing no substantial change in the overall effect size upon the exclusion of individual studies.

OUTLOOK

This meta-analysis supports a significant association between elevated serum angiopoietin-2 levels and increased risk of AKI. The observed differential association between adults and children highlights the need for further targeted research to understand these age-specific variations.

Personalized prediction of mortality in patients with acute ischemic stroke using explainable artificial intelligence

BACKGROUND

Research into the acute kidney disease (AKD) after acute ischemic stroke (AIS) is rare, and how clinical features influence its prognosis remain unknown. We aim to employ interpretable machine learning (ML) models to study AIS and clarify its decision-making process in identifying the risk of mortality.

METHODS

We conducted a retrospective cohort study involving AIS patients from January 2020 to June 2021. Patient data were randomly divided into training and test sets. Eight ML algorithms were employed to construct predictive models for mortality. The performance of the best model was evaluated using various metrics. Furthermore, we created an artificial intelligence (AI)-driven web application that leveraged the top ten most crucial features for mortality prediction.

RESULTS

The study cohort consisted of 1633 AIS patients, among whom 257 (15.74%) developed subacute AKD, 173 (10.59%) experienced AKI recovery, and 65 (3.98%) met criteria for both AKI and AKD. The mortality rate stood at 4.84%. The LightGBM model displayed superior performance, boasting an AUROC of 0.96 for mortality prediction. The top five features linked to mortality were ACEI/ARE, renal function trajectories, neutrophil count, diuretics, and serum creatinine. Moreover, we designed a web application using the LightGBM model to estimate mortality risk.

CONCLUSIONS

Complete renal function trajectories, including AKI and AKD, are vital for fitting mortality in AIS patients. An interpretable ML model effectively clarified its decision-making process for identifying AIS patients at risk of mortality. The AI-driven web application has the potential to contribute to the development of personalized early mortality prevention.

SIRT1 alleviates Cd nephrotoxicity through NF-κB/p65 deacetylation-mediated pyroptosis in rat renal tubular epithelial cells

Cadmium (Cd) is a widely distributed environmental pollutant, primarily causing nephrotoxicity through renal proximal tubular cell impairment. Pyroptosis is an inflammation-related nucleotide-binding oligomerization segment-like receptor family 3 (NLRP3)-dependent pathway for programmed cell death. We previously reported that inappropriate inflammation caused by Cd is a major contributor to kidney injury. Therefore, research on Cd-induced inflammatory response and pyroptosis may clarify the mechanisms underlying Cd-induced nephrotoxicity. In this study, we observed that Cd-induced nephrotoxicity is associated with NLRP3 inflammasome activation, leading to an increase in proinflammatory cytokine expression and secretion, as well as pyroptosis-related gene upregulation, both in primary rat proximal tubular (rPT) cells and kidney tissue from Cd-treated rats. In vitro, these effects were significantly abrogated through siRNA-based Nlrp3 silencing; thus, Cd may trigger pyroptosis through an NLRP3 inflammasome-dependent pathway. Moreover, Cd exposure considerably elevated reactive oxygen species (ROS) content. N-acetyl-l-cysteine, an ROS scavenger, mitigated Cd-induced NLRP3 inflammasome activation and subsequent pyroptosis. Mechanistically, Cd hindered the expression and deacetylase activity of SIRT1, eventually leading to a decline in SIRT1-p65 interactions, followed by an elevation in acetylated p65 levels. The administration of resveratrol (a SIRT1 agonist) or overexpression of Sirt1 counteracted Cd-induced RELA/p65/NLRP3 pathway activation considerably, leading to pyroptosis. This is the first study to reveal significant contributions of SIRT1-triggered p65 deacetylation to pyroptosis and its protective effects against Cd-induced chronic kidney injury. Our results may aid in developing potential therapeutic strategies for preventing Cd-induced pyroptosis through SIRT1-mediated p65 deacetylation.

Acute Kidney Injury in Neonatal Intensive Care Unit: Epidemiology, Diagnosis and Risk Factors

Acute kidney injury (AKI) is associated with long-term consequences and poor outcomes in the neonatal intensive care unit. Its precocious diagnosis represents one of the hardest challenges in clinical practice due to the lack of sensitive and specific biomarkers. Currently, neonatal AKI is defined with urinary markers and serum creatinine (sCr), with limitations in early detection and individual treatment. Biomarkers and risk factor scores were studied to predict neonatal AKI, to early identify the stage of injury and not the damage and to anticipate late increases in sCr levels, which occurred when the renal function already began to decline. Sepsis is the leading cause of AKI, and sepsis-related AKI is one of the main causes of high mortality. Moreover, preterm neonates, as well as patients with post-neonatal asphyxia or after cardiac surgery, are at a high risk for AKI. Critical patients are frequently exposed to nephrotoxic medications, representing a potentially preventable cause of AKI. This review highlights the definition of neonatal AKI, its diagnosis and new biomarkers available in clinical practice and in the near future. We analyze the risk factors involving patients with AKI, their outcomes and the risk for the transition from acute damage to chronic kidney disease.

Association between Serum Magnesium Levels and Risk of Acute Kidney Injury in Patients with Traumatic Brain Injury: A Retrospective Cohort Study from the MIMIC-IV Database

INTRODUCTION

The occurrence of acute kidney injury (AKI) is associated with a higher risk of mortality in patients with traumatic brain injury (TBI). This study aimed to explore the relationship between serum magnesium levels and the risk of AKI in patients with TBI.

METHODS

Patients with TBI were identified from the Medical Information Mart Intensive Care IV (MIMIC-IV) 2008-2019. The relationship between serum magnesium levels at admission and magnesium coefficient of variation (CV) during hospitalization and the risk of AKI was analyzed using multivariable logistic regression analysis and expressed as odds ratio (OR) and 95% confidence interval (CI). Subgroup analyses were performed according to Glasgow Coma Scale (GCS) score (<14, ≥14), sepsis (no, yes), and estimated glomerular filtration rate (eGFR; <60, ≥60).

RESULTS

Of the 991 patients included, 140 (14.13%) developed AKI during hospitalization. Patients with magnesium levels ≤1.7 mg/dL (tertile 1) (OR = 1.68, 95% CI: 1.01-2.81) were associated with a higher risk of AKI compared to those with magnesium levels of 1.7-2.0 mg/dL (tertile 2), but no association was found in those with magnesium levels >2.0 mg/dL (tertile 3) (p = 0.479). For magnesium CV, patients with magnesium CV >10% (tertile 3) (OR = 2.26, 95% CI: 1.16-4.41) were linked to an increased risk of AKI compared to those with magnesium CV ≤4% (tertile 1), but there may be a slight association between magnesium CV of 4%-10% (tertile 2) and AKI risk (OR = 1.86, 95% CI: 0.99-3.48; p = 0.053). Subgroup analyses showed that lower magnesium levels (≤1.7 mg/dL) or greater magnesium CV (>10%) were associated with a higher risk of AKI only in patients with a GCS score ≥14, non-sepsis, or eGFR ≥60 mL/min/1.73 m2 (p < 0.05).

CONCLUSION

Lower serum magnesium levels at admission or greater magnesium CV during hospitalization were associated with a higher risk of AKI in patients with TBI.

Systematic Review of Kidney Injury Biomarkers for the Evaluation of CKD of Uncertain Etiology

Introduction

Chronic kidney disease of uncertain etiology (CKDu) is an incompletely defined phenotype of chronic kidney disease (CKD) affecting young individuals mostly in agricultural communities in Central America and South Asia. CKDu is a diagnosis of exclusion made in individuals from endemic regions.

Methods

We conducted a systematic review of the primary literature on urinary and plasma kidney injury biomarkers measured in the setting of CKDu (through February 2023). The literature was identified via a Web of Science search and hand search of the references of previously identified literature. Search terms included "CKDu," "Mesoamerican Nephropathy," "CKD of unknown etiology," "Chronic Interstitial Nephritis in Agricultural Communities," "biomarker," "urin∗," and/or "plasma."

Results

A total of 25 papers were included. The 2 most frequently measured biomarkers were urinary kidney injury molecule-1 (KIM-1) and urinary neutrophil gelatinase-associated lipocalin (NGAL). There was substantial variability in study design, laboratory assay methods, and statistical methodology, which prohibited meta-analysis.

Conclusion

Biomarkers that identify tubulointerstitial disease early and accurately may substantially accelerate progress in the study of CKDu and facilitate public health approaches that eventually lead to its prevention and elimination. To date, the literature is limited by relatively small sample sizes and methodological limitations which should be addressed in future studies.

Effects of inpatient creatinine testing frequency on acute kidney injury identification and staging: a historical cohort study

BACKGROUND

Acute kidney injury (AKI) is a multifactorial condition often induced by drugs commonly used in hospitals. Identifying and staging AKI necessitates frequent monitoring of renal function.

AIM

To assess the impact of real-world hospital practices regarding serum creatinine (SCr) testing on the identification and staging of AKI, and its implications for adjusting drug doses.

METHOD

A historical cohort study utilizing hospital records from all adult patients admitted between 01/06/2018 and 31/12/2020 was conducted. Patients with no SCr assessment during their stay or those with an SCr at admission ≥ 2 mg/dL were excluded. AKI was determined using two criteria, namely AKIN and KDIGO, considering the time intervals between two SCr tests as outlined in the criteria. Additionally, patients with SCr increases exceeding AKI limits, regardless the time interval, were also identified. The estimated glomerular filtration rate (eGFR) and kinetic eGFR (KeGFR) were calculated.

RESULTS

During the study period, 17,269 hospitalizations and 62,255 SCr tests were recorded. Among the 17,032 hospitalizations with a length of stay > 48 h, 46.8% experienced periods with no SCr tests performed for more than 48 h. Any stage of AKI was identified in 7.0% of patients and in 9.1% using AKI and KDIGO criteria, respectively. Ignoring time limits in both criteria revealed potential AKI in 1942 patients (11.2%), indicating a potential underdiagnosis of AKI by 37.5% or 19.1%, depending on the criteria used. A total of 76 drugs requiring dose adjustment in patients with eGFR ≤ 50 ml/min were prescribed in 78.5% admissions. These drugs were prescribed in 87.9% of patients potentially underdiagnosed with AKIN and in 88.9% with KDIGO.

CONCLUSION

There is a need for changes in the established hospital procedures to ensure more frequent testing of SCr levels. Implementing an advanced scope of practice for clinical pharmacists could support these changes.

Targeting inflammation in perivascular cells and neuroimmune interactions for treating kidney disease

Inflammation plays a crucial role in the pathophysiology of various kidney diseases. Kidney perivascular cells (pericytes/fibroblasts) are responsible for producing proinflammatory molecules, promoting immune cell infiltration, and enhancing inflammation. Vascular adhesion protein-1, expressed in kidney perivascular cells, is an ectoenzyme that catalyzes the oxidative deamination of primary amines with the production of hydrogen peroxide in the extracellular space. Our study demonstrated that blocking this enzyme suppressed hydrogen peroxide production and neutrophil infiltration, thereby reducing renal ischemia-reperfusion injury. Sphingosine 1-phosphate (S1P) signaling was also observed to play an essential role in the regulation of perivascular inflammation. S1P, which is produced in kidney perivascular cells, is transported into the extracellular space via spinster homolog 2, and then binds to S1P receptor-1 expressed in perivascular cells. Upon injury, inflammatory signaling in perivascular cells is enhanced by this pathway, thereby promoting immune cell infiltration and subsequent fibrosis. Furthermore, inhibition of S1P transport by spinster homolog 2 reduces kidney fibrosis. Hypoxia-inducible factor-prolyl hydroxylase inhibitors can restore the capacity for erythropoietin production in kidney perivascular cells. Animal data suggested that these drugs could also alleviate kidney and lipid inflammation although the precise mechanism is still unknown. Neuroimmune interactions have been attracting significant attention due to their potential to benefit patients with inflammatory diseases. Vagus nerve stimulation is one of the most promising strategies for harnessing neuroimmune interactions and attenuating inflammation associated with various diseases, including kidney disease. Using cutting-edge tools, the vagal afferents-C1 neurons-sympathetic nervous system-splenic nerve-spleen-kidney axis responsible for kidney protection induced by vagus nerve stimulation was identified in our study. Further research is required to decipher other crucial systems that control kidney inflammation and to determine whether these novel strategies can be applied to patients with kidney disease.

Double-negative T cells have a reparative role after experimental severe ischemic acute kidney injury

T cells mediate organ injury and repair. A proportion of unconventional kidney T cells called double-negative (DN) T cells (TCR+ CD4- CD8-), with anti-inflammatory properties, were previously demonstrated to protect from early injury in moderate experimental acute kidney injury (AKI). However, their role in repair after AKI has not been studied. We hypothesized that DN T cells mediate repair after severe AKI. C57B6 mice underwent severe (40 min) unilateral ischemia-reperfusion injury (IRI). Kidney DN T cells were studied by flow cytometry and compared with gold-standard anti-inflammatory CD4+ regulatory T cells (Tregs). In vitro effects of DN T cells and Tregs on renal tubular epithelial cell (RTEC) repair after injury were quantified with live-cell analysis. DN T cells, Tregs, CD4, or vehicle were adoptively transferred after severe AKI. Glomerular filtration rate (GFR) was measured using fluorescein isothiocyanate (FITC)-sinistrin. Fibrosis was assessed with Masson's trichrome staining. Profibrotic genes were measured with qRT-PCR. Percentages and the numbers of DN T cells substantially decreased during repair phase after severe AKI, as well as their activation and proliferation. Both DN T cells and Tregs accelerated RTEC cell repair in vitro. Post-AKI transfer of DN T cells reduced kidney fibrosis and improved GFR, as did Treg transfer. DN T cell transfer lowered transforming growth factor (TGF)β1 and α-smooth muscle actin (αSMA) expression. DN T cells reduced effector-memory CD4+ T cells and IL-17 expression. DN T cells undergo quantitative and phenotypical changes after severe AKI, accelerate RTEC repair in vitro as well as improve GFR and renal fibrosis in vivo. DN T cells have potential as immunotherapy to accelerate repair after AKI.NEW & NOTEWORTHY Double-negative (DN) T cells (CD4- CD8-) are unconventional kidney T cells with regulatory abilities. Their role in repair from acute kidney injury (AKI) is unknown. Kidney DN T cell population decreased during repair after ischemic AKI, in contrast to regulatory T cells (Tregs) which increased. DN T cell administration accelerated tubular repair in vitro, while after severe in vivo ischemic injury reduced kidney fibrosis and increased glomerular filtration rate (GFR). DN T cell infusion is a potential therapeutic agent to improve outcome from severe AKI.

Renal arterial resistive index versus novel biomarkers for the early prediction of sepsis-associated acute kidney injury

Acute kidney injury (AKI) is a critical complication of sepsis. There is a continuous need to identify and validate biomarkers for early detection. Serum and urinary biomarkers have been investigated, such as neutrophil gelatinase associated lipocalin (NGAL) and cystatin C (Cys C), but their reliability in the intensive care unit (ICU) remains unknown. Renal hemodynamics can be investigated by measuring the renal resistive index (RRI). This study aimed to compare the performance of RRI, serum NGAL (sNGAL), urinary NGAL (uNGAL), and serum Cys C levels as early predictors of the diagnosis and persistence of sepsis-associated AKI. A total of 166 adult patients with sepsis syndrome were enrolled immediately after ICU admission. Biomarkers were measured directly (T1) and on day 3 (T3). RRI was measured directly (T1) and 24 h later (T2). Patients were categorized (according to the occurrence and persistence of AKI within the first 7 days) into three groups: no AKI, transient AKI, and persistent AKI. The incidence rate of sepsis-associated AKI was 60.2%. Sixty-six patients were categorized as in the no AKI group, while another 61 were in transient AKI and only 39 were in persistent AKI. The RRI value (T1 ≥ 0.72) was the best tool for predicting AKI diagnosis (area under the receiver operating characteristic curve, AUROC = 0.905). Cys C (T1 ≥ 15.1 mg/l) was the best tool to predict the persistence of AKI (AUROC = 0.977). RRI (T1) was the best predictive tool for sepsis-associated AKI, while Cys C was the best predictor of its persistence and 28-day mortality.

Advanced chronic kidney disease after surgery and the contribution of acute kidney disease: a national observational cohort study

BACKGROUND

Limited knowledge exists regarding long-term renal outcomes after noncardiac surgery. This study investigated the incidence of, and risk factors for, developing advanced chronic kidney disease (CKD) and major adverse kidney events within 1 yr of surgery in a nationwide cohort.

METHODS

Adults without renal dysfunction before noncardiac surgery in Sweden were included between 2007 and 2013 in this observational multicentre cohort study. We analysed data from a national surgical database linked to several national and quality outcome registries. Associations of perioperative risk factors with advanced CKD (estimated glomerular filtration rate [eGFR] <30 ml min-1 1.73 m-2) and major adverse kidney events within 1 yr (MAKE365, comprising eGFR <30 ml min-1 1.73 m-2, chronic dialysis, death) were quantified.

RESULTS

Of 237,124 patients, 1597 (0.67%) developed advanced CKD and 16,789 (7.1%) developed MAKE365. Risk factors for advanced CKD included higher ASA physical status, urological surgery, extended surgical duration, prolonged postoperative hospital stay, repeated surgery, and postoperative use of renin-angiotensin-aldosterone system blockers. Advanced acute kidney disease (AKD) (eGFR <30 ml min-1 1.73 m-2 within 90 postoperative days) occurred in 1661 (0.70%) patients and was associated with advanced CKD (subdistribution hazard ratio [SHR] 44.5, 95% confidence interval [CI] 38.7-51.1) and MAKE365 (hazard ratio [HR] 6.60, 95% CI 6.07-7.17). Among patients with advanced AKD after surgery 36% developed advanced CKD at 1 yr after surgery and 51% developed MAKE365.

CONCLUSIONS

Advanced CKD within 1 yr after surgery is uncommon but clinically important in patients without preoperative renal dysfunction. Advanced AKD after surgery constitutes a major risk factor for advanced CKD and MAKE365.

Butyrate promotes kidney resilience through a coordinated kidney protective response in tubular cells

Acute kidney injury (AKI) is common in hospitalized patients and increases short-term and long-term mortality. Treatment options for AKI are limited. Gut microbiota products such as the short-chain fatty acid butyrate have anti-inflammatory actions that may protect tissues, including the kidney, from injury. However, the molecular mechanisms of tissue protection by butyrate are poorly understood. Treatment with oral butyrate for two weeks prior to folic acid-induced AKI and during AKI improved kidney function and decreased tubular injury and kidney inflammation while stopping butyrate before AKI was not protective. Continuous butyrate preserved the expression of kidney protective factors such as Klotho, PGC-1α and Nlrp6 which were otherwise downregulated. In cultured tubular cells, butyrate blunted the maladaptive tubular cell response to a proinflammatory milieu, preserving the expression of kidney protective factors. Kidney protection afforded by this continuous butyrate schedule was confirmed in a second model of nephrotoxic AKI, cisplatin nephrotoxicity, where the expression of kidney protective factors was also preserved. To assess the contribution of preservation of kidney protective factors to kidney resilience, recombinant Klotho was administered to mice with cisplatin-AKI and shown to preserve the expression of PGC-1α and Nlrp6, decrease kidney inflammation and protect from AKI. In conclusion, butyrate promotes kidney resilience to AKI and decreases inflammation by preventing the downregulation of kidney protective genes such as Klotho. This information may be relevant to optimize antibiotic management during hospitalization.

Sensing Dying Cells in Health and Disease: The Importance of Kidney Injury Molecule-1

Kidney injury molecule-1 (KIM-1), also known as T-cell Ig and mucin domain-1 (TIM-1), is a widely recognized biomarker for AKI, but its biological function is less appreciated. KIM-1/TIM-1 belongs to the T-cell Ig and mucin domain family of conserved transmembrane proteins, which bear the characteristic six-cysteine Ig-like variable domain. The latter enables binding of KIM-1/TIM-1 to its natural ligand, phosphatidylserine, expressed on the surface of apoptotic cells and necrotic cells. KIM-1/TIM-1 is expressed in a variety of tissues and plays fundamental roles in regulating sterile inflammation and adaptive immune responses. In the kidney, KIM-1 is upregulated on injured renal proximal tubule cells, which transforms them into phagocytes for clearance of dying cells and helps to dampen sterile inflammation. TIM-1, expressed in T cells, B cells, and natural killer T cells, is essential for cell activation and immune regulatory functions in the host. Functional polymorphisms in the gene for KIM-1/TIM-1, HAVCR1 , have been associated with susceptibility to immunoinflammatory conditions and hepatitis A virus-induced liver failure, which is thought to be due to a differential ability of KIM-1/TIM-1 variants to bind phosphatidylserine. This review will summarize the role of KIM-1/TIM-1 in health and disease and its potential clinical applications as a biomarker and therapeutic target in humans.

Acute Kidney Injury and Subsequent Kidney Failure With Replacement Therapy Incidence in Older Adults With Advanced CKD: A Cohort Study of US Veterans

Rationale & Objective

Advanced age is a major risk factor for chronic kidney disease (CKD) development, which has high heterogeneity in disease progression. Acute kidney injury (AKI) hospitalization rates are increasing, especially among older adults. Previous AKI epidemiologic analyses have focused on hospitalized populations, which may bias results toward sicker populations. This study examined the association between AKI and incident kidney failure with replacement therapy (KFRT) while evaluating age as an effect modifier of this relationship.

Study Design

Retrospective cohort study.

Setting & Participants

24,133 Veterans at least 65 years old with incident CKD stage 4 from 2011 to 2013.

Exposures

AKI, AKI severity, and age.

Outcomes

KFRT and death.

Analytical Approach

The Fine-Gray competing risk regression was used to model AKI and incident KFRT with death as a competing risk. A Cox regression was used to model AKI severity and death.

Results

Despite a nonsignificant age interaction between AKI and KFRT, a clinically relevant combined effect of AKI and age on incident KFRT was observed. Compared with our oldest age group without AKI, those aged 65-74 years with AKI had the highest risk of KFRT (subdistribution HR [sHR], 14.9; 95% CI, 12.7-17.4), whereas those at least 85 years old with AKI had the lowest (sHR, 1.71; 95% CI, 1.22-2.39). Once Veterans underwent KFRT, their risk of death increased by 44%. A 2-fold increased risk of KFRT was observed across all AKI severity stages. However, the risk of death increased with worsening AKI severity.

Limitations

Our study lacked generalizability, was restricted to ever use of medications, and used inpatient serum creatinine laboratory results to define AKI and AKI severity.

Conclusions

In this national cohort, advanced age was protective against incident KFRT but not death. This is likely explained by the high frequency of deaths observed in this population (51.1%). Nonetheless, AKI and younger age are substantial risk factors for incident KFRT.

Antibiotic-induced intestinal microbiota depletion can attenuate the acute kidney injury to chronic kidney disease transition via NADPH oxidase 2 and trimethylamine-N-oxide inhibition

Intestinal microbiota and their metabolites affect systemic inflammation and kidney disease outcomes. Here, we investigated the key metabolites associated with the acute kidney injury (AKI)-to chronic kidney disease (CKD) transition and the effect of antibiotic-induced microbiota depletion (AIMD) on this transition. In 61 patients with AKI, 59 plasma metabolites were assessed to determine the risk of AKI-to-CKD transition. An AKI-to-CKD transition murine model was established four weeks after unilateral ischemia-reperfusion injury (IRI) to determine the effects of AIMD on the gut microbiome, metabolites, and pathological responses related to CKD transition. Human proximal tubular epithelial cells were challenged with CKD transition-related metabolites, and inhibitory effects of NADPH oxidase 2 (NOX2) signals were tested. Based on clinical metabolomics, plasma trimethylamine N-oxide (TMAO) was associated with a significantly increased risk for AKI-to-CKD transition [adjusted odds ratio 4.389 (95% confidence interval 1.106-17.416)]. In vivo, AIMD inhibited a unilateral IRI-induced increase in TMAO, along with a decrease in apoptosis, inflammation, and fibrosis. The expression of NOX2 and oxidative stress decreased after AIMD. In vitro, TMAO induced fibrosis with NOX2 activation and oxidative stress. NOX2 inhibition successfully attenuated apoptosis, inflammation, and fibrosis with suppression of G2/M arrest. NOX2 inhibition (in vivo) showed improvement in pathological changes with a decrease in oxidative stress without changes in TMAO levels. Thus, TMAO is a key metabolite associated with the AKI-to-CKD transition, and NOX2 activation was identified as a key regulator of TMAO-related AKI-to-CKD transition both in vivo and in vitro.

Statistical analysis plan for the biomarker-guided intervention to prevent acute kidney injury after major surgery (BigpAK-2) study: An international randomised controlled multicentre trial

Objective

This article describes the statistical analysis plan for the Biomarker-guided intervention to prevent AKI after major surgery (BigpAK-2) trial.

Design

Adaptive trial design with an interim analysis after enrolment of 618 evaluable patients.

Setting

The BigpAK.-2 trial is an international, prospective, randomised controlled multicentre study.

Participants

The BigpAK-2 study enrols patients after major surgery who are admitted to the intensive care or high dependency unit and are at high-risk for postoperative AKI as identified by urinary biomarkers (tissue inhibitor of metalloproteinases-2 and insulin-like growth factor binding protein 7 ([TIMP-2]∗[IGFBP7]) will be enrolled.

Intervention

Patients are randomly and evenly allocated to standard of care (control) group or the implementation of a nephroprotective care bundle (intervention group), as recommended by the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. The KDIGO care bundle recommends discontinuation of nephrotoxic agents if possible, ensuring adequate volume status and perfusion pressure, considering functional haemodynamic monitoring, regular monitoring of serum creatinine and urine output, avoiding hyperglycemia, and considering alternatives to radiocontrast procedures when possible.

Results

The BigpAK-2 study investigates whether the biomarker-gudied implementation of the KDIGO care bundle reduces the incidence of moderate or severe AKI (stage 2 or 3), according to the KDIGO 2012 criteria, within 72 h after surgery.

Conclusion

AKI is a common and often severe complication after major surgery. As no specific treatments exist, prevention of AKI is of high importance. The BigpAK-2 study investigates a promising approach to prevent AKI after major surgery.

Trial registration

The trial was registered prior to start at clinicaltrials.gov; NCT04647396.

MondoA and AKI and AKI-to-CKD Transition

Key Points

Background

Elderly individuals and patients with CKD are at a higher risk of AKI. The transcription factor MondoA is downregulated in the kidneys of aged individuals or patients with AKI; however, its roles in AKI development and the AKI-to-CKD transition remain unknown.

Methods

We investigated the expression of MondoA in human kidney biopsy samples, ischemia-reperfusion–injured (IRI) mouse kidneys, and cultured proximal tubular epithelial cells under hypoxia/reoxygenation. The role of MondoA during the initial and recovery phases after IRI was evaluated using proximal tubule–specific MondoA knockout mice and MondoA-deficient proximal tubular epithelial cells. Furthermore, we explored the involvement of Rubicon and transcription factor EB (TFEB), both of which are downstream factors of MondoA.

Results

MONDOA expression was decreased in the renal tubules of patients with CKD. In mouse kidneys, MondoA expression was decreased under ischemia, whereas its expression was increased during reperfusion. Genetic ablation of MondoA in proximal tubular epithelial cells inhibited autophagy and increased vulnerability to AKI through increased expression of Rubicon. Ablation of Rubicon in MondoA-deficient IRI kidneys activated autophagy and protected mitochondrial function. MondoA ablation during the recovery phase after ischemia-reperfusion aggravated kidney injury through downregulation of the TFEB-peroxisome proliferator-activated receptor-γ coactivator-1α axis. Pharmacological upregulation of TFEB contributed to maintaining mitochondrial biogenesis and increased peroxisome proliferator-activated receptor-γ coactivator-1α transcription.

Conclusions

Our findings demonstrate that MondoA protected against vulnerability to AKI by maintaining autophagy and subsequently supporting mitochondrial function to prevent progression to CKD.

Effects of cell-free DNA on kidney disease and intervention strategies

Kidney disease has become a global public health problem. Patients with end-stage kidney disease must rely on dialysis or undergo renal transplantation, placing heavy burdens on their families and society. Therefore, it is important to develop new therapeutic targets and intervention strategies during early stages of chronic kidney disease. The widespread application of liquid biopsy has led to an increasing number of studies concerning the roles of cell-free DNA (cfDNA) in kidney disease. In this review, we summarize relevant studies concerning the roles of cfDNA in kidney disease and describe various strategies for targeted removal of cfDNA, with the goal of establishing novel therapeutic approaches for kidney disease.

Reactive oxygen/nitrogen species scavenging and inflammatory regulation by renal-targeted bio-inspired rhodium nanozymes for acute kidney injury theranostics

Acute kidney injury (AKI) results from the rapid deterioration of renal function, which is mainly treated by transplantation and dialysis, and has a high mortality rate. Inflammation induced by excess reactive oxygen/nitrogen species (RONS) plays a crucial role in AKI. Although small molecule antioxidants have been utilized to alleviate AKI, low bioavailability and side-effect of these drugs tremendously limit their clinical use. Hence, we successfully construct ultra-small (2-4 nm) rhodium nanoparticles modified with l-serine (denoted as Rh-Ser). Our results show that Rh-Ser with multiple enzyme-mimicking activities, allows remove various RONS to protect damaged kidney cells. Additionally, the ultrasmall size of Rh-Ser is conducive to enrichment in the renal tubules, and the modification of l-serine enables Rh-Ser to bind to kidney injury molecule-1, which is highly expressed on the surface of damaged renal cells, thereby targeting the damaged kidney and increasing the retention time. Moreover, Rh-Ser allows the production of oxygen at the inflammatory site, thus further improving hypoxia and inhibiting pro-inflammatory macrophages to relieve inflammation, and increasing the survival rate of AKI mice from 0 to 80%, which exhibits a better therapeutic effect than that of small molecule drug. Photoacoustic and fluorescence imaging can effectively monitor and evaluate the enrichment and therapeutic effect of Rh-Ser. Our study provides a promising strategy for the targeted treatment of AKI via RONS scavenging and inflammatory regulation.

Exploiting urine-derived induced pluripotent stem cells for advancing precision medicine in cell therapy, disease modeling, and drug testing

The field of regenerative medicine has witnessed remarkable advancements with the emergence of induced pluripotent stem cells (iPSCs) derived from a variety of sources. Among these, urine-derived induced pluripotent stem cells (u-iPSCs) have garnered substantial attention due to their non-invasive and patient-friendly acquisition method. This review manuscript delves into the potential and application of u-iPSCs in advancing precision medicine, particularly in the realms of drug testing, disease modeling, and cell therapy. U-iPSCs are generated through the reprogramming of somatic cells found in urine samples, offering a unique and renewable source of patient-specific pluripotent cells. Their utility in drug testing has revolutionized the pharmaceutical industry by providing personalized platforms for drug screening, toxicity assessment, and efficacy evaluation. The availability of u-iPSCs with diverse genetic backgrounds facilitates the development of tailored therapeutic approaches, minimizing adverse effects and optimizing treatment outcomes. Furthermore, u-iPSCs have demonstrated remarkable efficacy in disease modeling, allowing researchers to recapitulate patient-specific pathologies in vitro. This not only enhances our understanding of disease mechanisms but also serves as a valuable tool for drug discovery and development. In addition, u-iPSC-based disease models offer a platform for studying rare and genetically complex diseases, often underserved by traditional research methods. The versatility of u-iPSCs extends to cell therapy applications, where they hold immense promise for regenerative medicine. Their potential to differentiate into various cell types, including neurons, cardiomyocytes, and hepatocytes, enables the development of patient-specific cell replacement therapies. This personalized approach can revolutionize the treatment of degenerative diseases, organ failure, and tissue damage by minimizing immune rejection and optimizing therapeutic outcomes. However, several challenges and considerations, such as standardization of reprogramming protocols, genomic stability, and scalability, must be addressed to fully exploit u-iPSCs' potential in precision medicine. In conclusion, this review underscores the transformative impact of u-iPSCs on advancing precision medicine and highlights the future prospects and challenges in harnessing this innovative technology for improved healthcare outcomes.

Risk Prediction Models for Renal Function Decline After Cardiac Surgery Within Different Preoperative Glomerular Filtration Rate Strata

BACKGROUND

Our goal was to create a simple risk-prediction model for renal function decline after cardiac surgery to help focus renal follow-up efforts on patients most likely to benefit.

METHODS AND RESULTS

This single-center retrospective cohort study enrolled 24 904 patients who underwent cardiac surgery from 2012 to 2019 at Fuwai Hospital, Beijing, China. An estimated glomerular filtration rate (eGFR) reduction of ≥30% 3 months after surgery was considered evidence of renal function decline. Relative to patients with eGFR 60 to 89 mL/min per 1.73 m2 (4.5% [531/11733]), those with eGFR ≥90 mL/min per 1.73 m2 (10.9% [1200/11042]) had a higher risk of renal function decline, whereas those with eGFR ≤59 mL/min per 1.73 m2 (5.8% [124/2129]) did not. Each eGFR stratum had a different strongest contributor to renal function decline: increased baseline eGFR levels for patients with eGFR ≥90 mL/min per 1.73 m2, transfusion of any blood type for patients with eGFR 60 to 89 mL/min per 1.73 m2, and no recovery of renal function at discharge for patients with eGFR ≤59 mL/min per 1.73 m2. Different nomograms were established for the different eGFR strata, which yielded a corrected C-index value of 0.752 for eGFR ≥90 mL/min per 1.73 m2, 0.725 for eGFR 60-89 mL/min per 1.73 m2 and 0.791 for eGFR ≤59 mL/min per 1.73 m2.

CONCLUSIONS

Predictors of renal function decline over the follow-up showed marked differences across the eGFR strata. The nomograms incorporated a small number of variables that are readily available in the routine cardiac surgical setting and can be used to predict renal function decline in patients stratified by baseline eGFR.

TNIK depletion induces inflammation and apoptosis in injured renal proximal tubule epithelial cells

In the aftermath of acute kidney injury (AKI), surviving proximal tubule epithelia repopulate injured tubules to promote repair. However, a portion of cells fail to repair [termed failed-repair proximal tubule cells (FR-PTCs)] and exert ongoing proinflammatory and profibrotic effects. To better understand the molecular drivers of the FR-PTC state, we reanalyzed a mouse ischemia-reperfusion injury single-nucleus RNA-sequencing (snRNA-seq) atlas to identify Traf2 and Nck interacting kinase (Tnik) to be exclusively expressed in FR-PTCs but not in healthy or acutely injured proximal tubules after AKI (2 and 6 wk) in mice. We confirmed expression of Tnik protein in injured mouse and human tissues by immunofluorescence. Then, to determine the functional role of Tnik in FR-PTCs, we depleted TNIK with siRNA in two human renal proximal tubule epithelial cell lines (primary and immortalized hRPTECs) and analyzed each by bulk RNA-sequencing. Pathway analysis revealed significant upregulation of inflammatory signaling pathways, whereas pathways associated with differentiated proximal tubules such as organic acid transport were significantly downregulated. TNIK gene knockdown drove reduced cell viability and increased apoptosis, including differentially expressed poly(ADP-ribose) polymerase (PARP) family members, cleaved PARP-1 fragments, and increased annexin V binding to phosphatidylserine. Together, these results indicate that Tnik upregulation in FR-PTCs acts in a compensatory fashion to suppress inflammation and promote proximal tubule epithelial cell survival after injury. Modulating TNIK activity may represent a prorepair therapeutic strategy after AKI.NEW & NOTEWORTHY The molecular drivers of successful and failed repair in the proximal tubule after acute kidney injury (AKI) are incompletely understood. We identified Traf2 and Nck interacting kinase (Tnik) to be exclusively expressed in failed-repair proximal tubule cells after AKI. We tested the effect of siTNIK depletion in two proximal tubule cell lines followed by bulk RNA-sequencing analysis. Our results indicate that TNIK acts to suppress inflammatory signaling and apoptosis in injured renal proximal tubule epithelial cells to promote cell survival.

Serotonin regulation of mitochondria in kidney diseases

Serotonin, while conventionally recognized as a neurotransmitter in the CNS, has recently gained attention for its role in the kidney. Specifically, serotonin is not only synthesized in the kidney, but it also regulates glomerular function, vascular resistance, and mitochondrial homeostasis. Because of serotonin's importance to mitochondrial health, this review is focused on the role of serotonin and its receptors in mitochondrial function in the context of acute kidney injury, chronic kidney disease, and diabetic kidney disease, all of which are characterized by mitochondrial dysfunction and none of which has approved pharmacological treatments. Evidence indicates that activation of certain serotonin receptors can stimulate mitochondrial biogenesis (MB) and restore mitochondrial homeostasis, resulting in improved renal function. Serotonin receptor agonists that induce MB are therefore of interest as potential therapeutic strategies for renal injury and disease. SIGNIFICANCE STATEMENT: Mitochondrial dysfunction is associated with many human renal diseases such as acute kidney injury, chronic kidney disease, and diabetic kidney disease, which are associated with increased morbidity and mortality. Unfortunately, none of these pathologies has an FDA-approved pharmacological intervention, underscoring the urgency of identifying new therapeutics for such disorders. Studies show that induction of mitochondrial biogenesis via serotonin (5-hydroxytryptamine, 5-HT) receptors reduces kidney injury markers, restores mitochondrial and renal function after kidney injury, and decreases mortality, suggesting that targeting 5-HT receptors may be a promising therapeutic avenue for mitochondrial dysfunction in kidney diseases. While numerous reviews describe the importance of mitochondria and mitochondrial quality control mechanisms in kidney disease, the relevance of 5-HT receptor-mediated mitochondrial metabolic modulation in the kidney has yet to be thoroughly explored.

Adolescent Kidney Outcomes after Extremely Preterm Birth and Neonatal Acute Kidney Injury: There May be More to the Story

OBJECTIVE

 Among children born extremely preterm (EP), the antecedents of chronic kidney disease (CKD), including neonatal acute kidney injury (nAKI), are not well characterized.

STUDY DESIGN

 This was a retrospective cohort pilot study. Participants (n = 36) were adolescents born before 28 weeks of gestation enrolled at birth into the extremely low gestational age newborn study, between 2002 and 2004, at the University of North Carolina. Participants were stratified by the primary exposure to nAKI, defined using the modified Kidney Disease Improving Global Outcomes nAKI criteria. Baseline serum creatinine (SCr) was defined as the lowest SCr after 48 to 72 postnatal hours. The primary outcome was an abnormal kidney profile during adolescence, defined as having one or more of these outcomes: elevated blood pressure (>120/80 mm Hg), microalbuminuria (urine microalbumin/creatinine >30 µg/g), or an abnormal kidney volume measured by ultrasound (total kidney volume corrected for body surface area <10th%ile for age).

RESULTS

 Half of the participants had a history of nAKI. Thirteen had stage 1 nAKI, four had stage 2, and one had stage 3 nAKI. At 15 years of age, 50% were overweight/obese, 31% had elevated blood pressure (BP), 11% had abnormal kidney volumes, and 17% had microalbuminuria. The relative risk for having an abnormal kidney profile during adolescence among participants with a history of nAKI was 0.63 (95% confidence interval: 0.3-1.3, p = 0.2).

CONCLUSION

 In this sample of adolescents born EP, a history of nAKI was not associated with elevated BP, microalbuminuria, or abnormal kidney volume. Future studies are needed in larger samples to better characterize the relationship between nAKI and CKD in EP-born children.

KEY POINTS

· Extremely preterm birth is associated with acute kidney injury.. · Extremely preterm birth is associated with chronic kidney disease.. · Neonatal acute kidney injury after extremely preterm birth was not associated with kidney outcomes..

Recent Update on Acute Kidney Injury-to-Chronic Kidney Disease Transition

Acute kidney injury (AKI) is characterized by an abrupt decline of excretory kidney function. The incidence of AKI has increased in the past decades. Patients diagnosed with AKI often undergo diverse clinical trajectories, such as early or late recovery, relapses, and even a potential transition from AKI to chronic kidney disease (CKD). Although recent clinical studies have demonstrated a strong association between AKI and progression of CKD, our understanding of the complex relationship between AKI and CKD is still evolving. No cohort study has succeeded in painting a comprehensive picture of these multi-faceted pathways. To address this lack of understanding, the idea of acute kidney disease (AKD) has recently been proposed. This presents a new perspective to pinpoint a period of heightened vulnerability following AKI, during which a patient could witness a substantial decline in glomerular filtration rate, ultimately leading to CKD transition. Although AKI is included in a range of kidney conditions collectively known as AKD, spanning from mild and self-limiting to severe and persistent, AKD can also occur without a rapid onset usually seen in AKI, such as when kidney dysfunction slowly evolves. In the present review, we summarize the most recent findings about AKD, explore the current state of biomarker discovery related to AKD, discuss the latest insights into pathophysiological underpinnings of AKI to CKD transition, and reflect on therapeutic challenges and opportunities that lie ahead.

BET inhibitor nanotherapy halts kidney damage and reduces chronic kidney disease progression after ischemia-reperfusion injury

Targeting epigenetic mechanisms has emerged as a potential therapeutic approach for the treatment of kidney diseases. Specifically, inhibiting the bromodomain and extra-terminal (BET) domain proteins using the small molecule inhibitor JQ1 has shown promise in preclinical models of acute kidney injury (AKI) and chronic kidney disease (CKD). However, its clinical translation faces challenges due to issues with poor pharmacokinetics and side effects. Here, we developed engineered liposomes loaded with JQ1 with the aim of enhancing kidney drug delivery and reducing the required minimum effective dose by leveraging cargo protection. These liposomes efficiently encapsulated JQ1 in both the membrane and core, demonstrating superior therapeutic efficacy compared to freely delivered JQ1 in a mouse model of kidney ischemia-reperfusion injury. JQ1-loaded liposomes (JQ1-NPs) effectively targeted the kidneys and only one administration, one-hour after injury, was enough to decrease the immune cell (neutrophils and monocytes) infiltration to the kidney-an early and pivotal step to prevent damage progression. By inhibiting BRD4, JQ1-NPs suppress the transcription of pro-inflammatory genes, such as cytokines (il-6) and chemokines (ccl2, ccl5). This success not only improved early the kidney function, as evidenced by decreased serum levels of BUN and creatinine in JQ1-NPs-treated mice, along with reduced tissue expression of the damage marker, NGAL, but also halted the production of extracellular matrix proteins (Fsp-1, Fn-1, α-SMA and Col1a1) and the fibrosis development. In summary, this work presents a promising nanotherapeutic strategy for AKI treatment and its progression and provides new insights into renal drug delivery.

Local Renal Treatments for Acute Kidney Injury: A Review of Current Progress and Future Translational Opportunities

Acute kidney injury (AKI) constitutes a significant public health concern, with limited therapeutic options to mitigate injury or expedite recovery. A novel therapeutic approach, local renal treatment, encompassing pharmacotherapy and surgical interventions, has exhibited positive outcomes in AKI management. Peri-renal administration, employing various delivery routes, such as the renal artery, intrarenal, and subcapsular sites, has demonstrated superiority over peripheral intravenous infusion. This review evaluates different drug delivery methods, analyzing their benefits and limitations, and proposes potential improvements. Renal decapsulation, particularly with the availability of minimally invasive techniques, emerges as an effective procedure warranting renewed consideration for AKI treatment. The potential synergistic effects of combined drug delivery and renal decapsulation could further advance AKI therapies. Clinical studies have already begun to leverage the benefits of local renal treatments, and with ongoing technological advancements, these modalities are expected to increasingly outperform systemic intravenous therapy.

Terpenes in the management of chronic kidney disease

Chronic kidney disease (CKD) is a chronic and progressive systemic condition that characterizes irreversible alterations in the kidneys' function and structure over an extended period, spanning months to years. CKD is the one of the major causes of mortality worldwide. However, very limited treatment options are available in the market for management of the CKD. Diabetes and hypertension are the key risk factors for the progression of CKD. It is majorly characterised by glomerulosclerosis, tubular atrophy, and interstitial fibrosis. Plants are considered safe and effective in treating various chronic conditions. A diverse group of phytoconstituents, including polyphenols, flavonoids, alkaloids, tannins, saponins, and terpenes, have found significant benefits in managing chronic ailments. Terpenes constitute a diverse group of plant compounds with various therapeutic benefits. Evidence-based pharmacological studies underscore the crucial role played by terpenes in preventing and managing CKD. These substances demonstrate the capacity to hinder detrimental pathways, such as oxidative stress, inflammation and fibrosis, thereby demonstrating benefit in renal dysfunction. This review offers a comprehensive overview of the roles and positive attributes of commonly occurring terpenes in managing the causes and risk factors of CKD and the associated conditions.

The copper transporter, SLC31A1, transcriptionally activated by ELF3, imbalances copper homeostasis to exacerbate cisplatin-induced acute kidney injury through mitochondrial dysfunction

Acute kidney injury (AKI) is a common complication of cisplatin chemotherapy, which greatly limits its clinical effect and application. This study explored the function of solute Carrier Family 31 Member 1 (SLC31A1) in cisplatin-induced AKI and its possible mechanism. Mice and HK-2 cells were exposed to cisplatin to establish the in vivo and in vitro AKI models. Cell viability was detected by CCK-8. Mitochondrial and oxidative damage was determined by Mito-Tracker Green staining, mtROS level, ATP production, mitochondrial membrane potential, MDA content and CAT activity. AKI was evaluated by renal function and histopathological changes. Apoptosis was detected by TUNEL and caspase-3 expression. Molecule expression was measured by RT-qPCR, Western blotting, and immunohistochemistry. Molecular mechanism was studied by luciferase reporter assay and ChIP. SLC31A1 level was predominantly increased by cisplatin exposure in AKI models. Notably, copper ion (Cu+) level was enhanced by cisplatin challenge. Moreover, Cu+ supplementation intensified cisplatin-induced cell death, mitochondrial dysfunction, and oxidative stress in HK-2 cells, indicating the involvement of cuproptosis in cisplatin-induced AKI, whereas these changes were partially counteracted by SLC31A1 knockdown. E74 like ETS transcription factor 3 (ELF3) could directly bind to SLC31A1 promoter and promote its transcription. ELF3 was up-regulated and positively correlated with SLC31A1 expression upon cisplatin-induced AKI. SLC31A1 silencing restored renal function, alleviated mitochondrial dysfunction, and apoptosis in cisplatin-induced AKI mice. ELF3 transcriptionally activated SLC31A1 to trigger cuproptosis that drove cisplatin-induced AKI through mitochondrial dysfunction, indicating that SLC31A1 might be a promising therapeutic target to mitigate AKI during cisplatin chemotherapy.

Purification-free synthesis of bright lactoglobulin@dye nanoprobe for second near-infrared fluorescence imaging of kidney dysfunction in vivo

Kidney disease is currently prevalent worldwide but only shows insidious symptoms in the early stages. The second near-infrared window (NIR-II) fluorescence imaging has become a widely used preclinical technology for evaluating renal dysfunction due to its high resolution and sensitivity. However, bright renal clearable NIR-II fluorescence nanoprobes with a simple synthesis process are still lacking. Herein, we develop a lactoglobulin (LG)@dye nanoprobe for NIR-II fluorescence imaging of kidney dysfunction in vivo based on a purification-free method. The nanoprobe was synthesized by simply mixing LG and IR820 in aqueous solutions at 70 °C for 2 h based on the covalent interaction between the meso-Cl in IR820 and LG. The synthesized LG@IR820 nanoprobe has bright and stable NIR-II fluorescence, ultra-small size (<5 nm), low toxicity, and renal-clearable ability. The high reaction efficiency and pure aqueous reaction media make the synthesis method purification-free. In a unilateral ureteral obstruction mouse model, incipient renal dysfunction assessment was achieved by LG@IR820 nanoprobe, which couldn't be diagnosed with conventional kidney function indicators. This study provides a bright and purification-free NIR-II LG@IR820 nanoprobe to visualize kidney dysfunction at the early stage.