Chronic kidney disease

Prevalence of kidney disease in patients with different types of cancer or hematological malignancies: a cross-sectional study

PURPOSE

This study investigated the prevalence and risk factors of acute kidney injury (AKI) and chronic kidney disease (CKD) in cancer patients with the aim of providing guidance for clinical treatment of cancer patients.

METHODS

A retrospective study was conducted on all cancer and hematological malignancy patients admitted to Xuanwu Hospital, Capital Medical University, from January 2018 to July 2023. The study population included patients aged 18-80 years with a confirmed cancer or malignancy diagnosis. Chi-square tests, Spearman's correlation, and logistic regression were used to evaluate the relationships between demographic factors, comorbidities, cancer types, antitumor drugs and the prevalence of AKI/CKD.

RESULTS

Among the 2438 participants, the prevalence rates of AKI and CKD were 3.69% and 7.88%, respectively. Patients with diabetes had higher prevalence of AKI/CKD than those without diabetes (OR = 1.66, 95% CI 1.01-2.68, p = 0.040; OR = 1.60, 95% CI 1.10-2.31, p = 0.012, respectively). In addition, a higher prevalence of CKD was observed in patients with hypertension (OR = 3.49, 95% CI 2.43-5.06, p < 0.001). Underweight patients were more likely to develop AKI (OR = 2.66, 95% CI 1.03-6.08, p = 0.029). Anthracyclines may contribute to a higher risk of AKI, and antimetabolites and immunomodulators may be associated with the development of CKD. Overall, patients with hematological malignancies had significantly higher rates of AKI/CKD than those with solid tumors. Among solid tumor patients, the prevalence of AKI/CKD was low in patients with lung and breast cancer.

CONCLUSIONS

AKI and CKD prevalence varies across cancer types, influenced by factors, such as diabetes, hypertension, body weight, and antitumor drugs. Tailored treatment plans are essential for improving cancer patient outcomes.

Insomnia and sleep duration for kidney function: Mendelian randomization study

OBJECTIVES

Extensive researches highlight the detrimental impact of sleep disorders such as insomnia and insufficient sleep duration on kidney function. However, establishing a clear causal relationship between insomnia, sleep duration, and kidney function remains challenging. This study aims to estimate this relationship using Mendelian randomization (MR).

METHODS

Independent genetic variants strongly associated with insomnia (N = 462,341) and sleep duration (N = 460,099) were selected as instrumental variables from corresponding genome-wide association studies (GWAS). Kidney function parameters, including serum creatinine, estimated glomerular filtration rate by cystatin C (eGFRcys), acute renal failure (ARF), chronic renal failure (CRF), kidney injury molecule-1, neutrophil gelatinase associated lipocalin, microalbuminuria, cystatin C, and β2 microglobulin, were derived from GWAS databases. A two-sample MR study was conducted to assess the causal relationship between sleep disorders and kidney function, and multivariable MR was used to identify potential mediators. The inverse-variance weighted was used as the primary estimate.

RESULTS

MR analysis found robust evidence indicating that insomnia and short sleep duration were associated with an increased risk of elevated serum creatinine, regardless of adjusting for obesity. Causal links between sleep duration and eGFRcys or cystatin C were also identified. While genetically predicted insomnia and sleep duration were found to potentially impact ARF, CRF, microalbuminuria, and β2 microglobulin, the p-values in multivariable MR analysis became nonsignificant. No pleiotropy was detected.

CONCLUSIONS

This study demonstrates a causal impact of insomnia on the risk of elevated serum creatinine and a positive effect of sleep duration on serum creatinine, eGFRcys, and cystatin C. Our findings also suggest their potential indirect effects on ARF, CRF, microalbuminuria, and β2 microglobulin mediated by obesity.

Exploring the relationship between creatine supplementation and renal function: insights from Mendelian randomization analysis

BACKGROUND

Creatine supplementation is ubiquitously consumed by fitness enthusiasts due to its perceived advantages in enhancing athletic performance. Although there is an increasing concern within this demographic regarding its possible impact on renal function, there is still a lack of rigorous scientific investigations into this alleged association.

METHODS

Data were collected through an online survey on the participants' demographics, creatine usage and concerns related to renal function. The reliability and validity of the survey were assessed using SPSS software. A total of 1129 participants responded to the survey, and chi-square tests were utilized for data analysis. To explore the potential association between creatine levels (as the exposure) and renal function (as the outcome), we utilized open-access genetic databases, and Mendelian randomization (MR) techniques were used to confirm this correlation.

RESULTS

Chi-square analysis revealed no significant association between creatine usage and renal function among the participants. Our MR analysis further supported this finding, demonstrating no significant association between creatine levels and six indicators assessing renal function (IVW, all with p values exceeding 0.05). Similar p values were consistently observed across other MR methods, confirming the absence of a statistical correlation.

CONCLUSIONS

This MR study offers compelling evidence indicating that creatine levels are not statistically associated with renal function, suggesting the potential to alleviate concerns within the fitness community and emphasizing the significance of evidence-based decision-making when considering nutritional supplementation.

Identification of serum biomarkers for chronic kidney disease using serum metabolomics

This study aimed to identify biomarkers for chronic kidney disease (CKD) by studying serum metabolomics. Serum samples were collected from 194 non-dialysis CKD patients and 317 healthy controls (HC). Using ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS), untargeted metabolomics analysis was conducted. A random forest model was developed and validated in separate sets of HC and CKD patients. The serum metabolomic profiles of patients with chronic kidney disease (CKD) exhibited significant differences compared to healthy controls (HC). A total of 314 metabolites were identified as significantly different, with 179 being upregulated and 135 being downregulated in CKD patients. KEGG enrichment analysis revealed several key pathways, including arginine biosynthesis, phenylalanine metabolism, linoleic acid metabolism, and purine metabolism. The diagnostic efficacy of the classifier was high, with an area under the curve of 1 in the training and validation sets and 0.9435 in the cross-validation set. This study provides comprehensive insights into serum metabolism in non-dialysis CKD patients, highlighting the potential involvement of abnormal biological metabolism in CKD pathogenesis. Exploring metabolites may offer new possibilities for the management of CKD.

Effectiveness and safety of finerenone in Chinese CKD patients without diabetes: a retrospective, real-world study

BACKGROUND

Finerenone, a non-steroidal mineralocorticoid receptor antagonist, has previously demonstrated its efficacy and safety in chronic kidney disease (CKD) associated with diabetes mellitus. Given its therapeutic potential, finerenone has been preliminarily explored in clinical practice for non-diabetic CKD patients. The effectiveness and safety in this population require further investigation in a real-world setting.

METHODS

This retrospective, real-world analysis included non-diabetic CKD patients receiving finerenone. The main clinical outcomes assessed were changes in urinary albumin-to-creatinine ratio (UACR) and estimated glomerular filtration rate (eGFR). Serum potassium (sK+) levels were also monitored. Data were collected at baseline, and then at 1 month and 3 months following treatment initiation.

RESULTS

Totally, 16 patients were included. There was a notable decrease in UACR from 1-month post-treatment, with a further reduction at 3 months, resulting in a median reduction of 200.41 mg/g (IQR, 84.04-1057.10 mg/g; P = 0.028; percent change, 44.52% [IQR, 31.79-65.42%]). The average eGFR at baseline was 80.16 ml/min/1.73m2, with no significant change after 1 month (80.72 ml/min/1.73m2, P = 0.594) and a slight numerical increase to 83.45 ml/min/1.73m2 (P = 0.484) after 3 months. During the 3-month follow-up, sK+ levels showed only minor fluctuations, with no significant differences compared to baseline, and remained within the normal range throughout the treatment period. No treatment discontinuation or hospitalization due to hyperkalemia was observed.

CONCLUSION

In non-diabetic CKD patients, finerenone showed good effectiveness and safety within a 3-month follow-up period. This study provides valuable real-world evidence supporting the use of finerenone in non-diabetic CKD and highlights the need for future large-scale prospective research to further validate its efficacy.

Efficacy and safety of dapagliflozin in children with kidney disease: real-world data

BACKGROUND

Dapagliflozin, a sodium-glucose cotransporter-2 inhibitor, has shown results in slowing estimated glomerular filtration rate (eGFR) decline and reducing proteinuria in adult patients with chronic kidney disease. This retrospective study examines dapagliflozin's effects in 22 children with kidney disease and proteinuria.

METHODS

Children with a median age of 15.6 years were treated with dapagliflozin for > 3 months between July 2022 and December 2023. All children had been treated with either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker for at least 1 month before starting dapagliflozin.

RESULTS

The most common kidney disease diagnoses in this study included Alport syndrome (n = 7) and medication-resistant nephrotic syndrome or focal segmental glomerulosclerosis (n = 7). After 6.1 months of treatment, dapagliflozin treatment did not result in significant changes in eGFR or proteinuria. However, at the latest follow-up, a statistically significant decrease in eGFR was noted (65.5 compared to the baseline 71.1 mL/min/1.73 m2, P = 0.003). Proteinuria remained stable between baseline and the last follow-up (final spot urine protein/creatinine ratio (uPCR) 0.7 vs. baseline uPCR 0.6 mg/mg, P = 0.489). In the subgroup analysis of children treated for > 8 months, the eGFR decline post-treatment changed from - 0.5 to - 0.2 ml/min/1.73 m2 per month (P = 0.634). Only two children discontinued dapagliflozin due to suspected adverse events.

CONCLUSIONS

Dapagliflozin has not been associated with serious side effects. Further prospective clinical trials are needed to confirm the efficacy and safety of dapagliflozin in children with kidney disease.

Contralateral renal change in a unilateral ureteral obstruction rat model using intravoxel incoherent motion diffusion-weighted imaging

OBJECTIVES

Most functional magnetic resonance research has primarily examined alterations in the affected kidney, often neglecting the contralateral kidney. Our study aims to investigate whether imaging parameters accurately depict changes in both the renal cortex and medulla in a unilateral ureteral obstruction rat model, thereby showcasing the utility of intravoxel incoherent motion (IVIM) in evaluating contralateral renal changes.

METHODS

Six rats underwent MR scans and were subsequently sacrificed for baseline histological examination. Following the induction of left ureteral obstruction, 48 rats were scanned, and the histopathological examinations were conducted on days 3, 7, 10, 14, 21, 28, 35, and 42. The apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudodiffusion (D*), and perfusion fraction (f) values were measured using IVIM.

RESULTS

On the 10th day of obstruction, both cortical and medullary ADC values differed significantly between the UUO10 group and the sham group (p < 0.01). The cortical D values showed statistically significant differences between UUO3 group and sham group (p < 0.01) but not among UUO groups at other time point. Additionally, the cortical and medullary f values were statistically significant between the UUO21 group and the sham group (p < 0.01). Especially, the cortical f values exhibited significant differences between the UUO21 group and the UUO groups with shorter obstruction time (at time point of 3, 7, 10, 14 day) (p < 0.01).

CONCLUSIONS

Significant hemodynamic alterations were observed in the contralateral kidney following renal obstruction. IVIM accurately captures changes in the unobstructed kidney. Particularly, the cortical f value exhibits the highest potential for assessing contralateral renal modifications.

Therapeutic effects of acupuncture therapy for kidney function and common symptoms in patients with chronic kidney disease: a systematic review and meta-analysis

Purpose: The number of clinical reports of acupuncture therapy in chronic kidney disease (CKD) is gradually increasing. This systematic review and meta-analysis aim to examine the therapeutic role of acupuncture therapy in kidney function and common symptoms in CKD patients.Methods: We searched Embase, PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, WanFang, and WeiPu for randomized controlled trials comparing acupuncture treatment with control or placebo groups. We assessed the effect of acupuncture therapy in CKD patients using a meta-analysis with the hartung-knapp-sidik-jonkman random effects model. In addition, we visualized keyword co-occurrence overlay visualization with the help of VOSviewer software to describe the research hotspots of acupuncture therapy and CKD.Results: A total of 24 studies involving 1494 participants were included. Compared to the control group, acupuncture therapy reduced serum creatinine levels (standardized mean difference [SMD]: -0.57; 95% CI -1.05 to -0.09) and relieved pruritus (SMD: -2.20; 95% CI -3.84, -0.57) in patients with CKD, while the TSA showed that the included sample size did not exceed the required information size. The included studies did not report acupuncture-related adverse events.Conclusions: Acupuncture is an effective and safe treatment for improving kidney function and relieving pruritic symptoms in patients with CKD, but the very low evidence may limit this conclusion. The TSA suggests that high-quality trials are needed to validate the efficacy of acupuncture therapy.

Ultrasound viscoelastic imaging in the noninvasive quantitative assessment of chronic kidney disease

BACKGROUND

This study aims to evaluate the clinical application value of ultrasound viscoelastic imaging in noninvasive quantitative assessment of chronic kidney disease (CKD).

METHODS

A total of 332 patients with CKD and 190 healthy adults as a control group were prospectively enrolled. Before kidney biopsy, ultrasound viscoelastic imaging was performed to measure the mean stiffness value (Emean), mean viscosity coefficient (Vmean), and mean dispersion coefficient (Dmean) of the renal. CKD patients were divided into three groups based on estimated glomerular filtration rate. The differences in clinic, pathology, ultrasound image parameters between the control and patient groups, or among different CKD groups were compared. The correlation between viscoelastic parameters and pathology were analyzed.

RESULTS

Emean, Vmean, and Dmean in the control group were less than the CKD group (p < 0.05). In the identification of CKD from control groups, the area under curve of Vmean, Dmean, Emean, and combining the three parameters is 0.90, 0.79, 0.69, 0.91, respectively. Dmean and Vmean were increased with the decline of renal function (p < 0.05). Vmean and Dmean were positively correlated with white blood cell, urea, serum creatinine, and uric acid (p < 0.05). Vmean is positively correlated with interstitial fibrosis and inflammatory cell infiltration grades (p < 0.001).

CONCLUSIONS

Ultrasound viscoelastic imaging has advantages in noninvasive quantitative identification and evaluating renal function of CKD. Emean > 6.61 kPa, Vmean > 1.86 Pa·s, or Dmean > 7.51 m/s/kHz may suggest renal dysfunction. Combining Vmean, Dmean, and Emean can improve the efficiency of identifying CKD.

Nitrogen doped carbon dots and gold nanoparticles mediated FRET for the detection of creatinine in human urine samples

Serum creatinine (CR) is regarded as one of the most sought out prognostic biomarkers in medical evaluation of chronic kidney disease (CKD). In light of the diagnostic significance of CR, the utility of a fluorescence biosensor for its detection in human urine specimens has been explored based on Förster resonance energy transfer (FRET) across nitrogen-doped carbon dots (N-CDs) and gold nanoparticles (GNPs). A straightforward microwave-assisted synthesis procedure has been adopted to prepare N-CDs (λexcitation = 400 nm, λemission = 540 ± 5 nm) with bright green emissions. On addition of pre-synthesized GNPs, the radiative emanation of the N-CDs is completely suppressed on account of FRET across the N-CDs and the GNPs. About 77 % of their fluorescence intensity is recovered after adding CR to GNPs@N-CDs nanocomposite. The limit of detection for CR sensing is estimated as 0.02 µg•mL-1. This biosensor is selective enough to recognize CR in the existence of potential interfering substances (e.g., ascorbic acid, glucose, glutathione, urea, and electrolytes). Its practical utility for CR detection has been validated further on the basis of satisfactory correlation with the benchmark Jaffe method, as observed in artificial/human urine specimens. Consequently, this manuscript marks a pioneering report on employing CDs and GNPs-based FRET for identifying CR in urine specimens of CKD patients.

TRIM65 deficiency alleviates renal fibrosis through NUDT21-mediated alternative polyadenylation

Chronic kidney disease (CKD) is a major global health concern and the third leading cause of premature death. Renal fibrosis is the primary process driving the progression of CKD, but the mechanisms behind it are not fully understood, making treatment options limited. Here, we find that the E3 ligase TRIM65 is a positive regulator of renal fibrosis. Deletion of TRIM65 results in a reduction of pathological lesions and renal fibrosis in mouse models of kidney fibrosis induced by unilateral ureteral obstruction (UUO)- and folic acid. Through screening with a yeast-hybrid system, we identify a new interactor of TRIM65, the mammalian cleavage factor I subunit CFIm25 (NUDT21), which plays a crucial role in fibrosis through alternative polyadenylation (APA). TRIM65 interacts with NUDT21 to induce K48-linked polyubiquitination of lysine 56 and proteasomal degradation, leading to the inhibition of TGF-β1-mediated SMAD and ERK1/2 signaling pathways. The degradation of NUDT21 subsequently altered the length and sequence content of the 3'UTR (3'UTR-APA) of several pro-fibrotic genes including Col1a1, Fn-1, Tgfbr1, Wnt5a, and Fzd2. Furthermore, reducing NUDT21 expression via hydrodynamic renal pelvis injection of adeno-associated virus 9 (AAV9) exacerbated UUO-induced renal fibrosis in the normal mouse kidneys and blocked the protective effect of TRIM65 deletion. These findings suggest that TRIM65 promotes renal fibrosis by regulating NUDT21-mediated APA and highlight TRIM65 as a potential target for reducing renal fibrosis in CKD patients.

Lupus nephritis-related chronic kidney disease

Lupus nephritis is a common complication of systemic lupus erythematosus (SLE) and a determinant of overall morbidity and mortality, as lupus nephritis-related chronic kidney disease (CKD) drives cardiovascular disease and secondary immunodeficiency. Two lines of action are required to prevent the progression of lupus nephritis-related CKD: suppression of autoimmune SLE activity, which is a risk factor for immunopathology-related irreversible kidney injury, and management of non-immune risk factors that contribute to CKD progression. As each episode or relapse of active lupus nephritis implicates CKD progression, preventing flares of lupus nephritis is a key treatment target. Non-immune risk factors of CKD mostly include causes of nephron hyperfiltration, such as obesity, hypertension, sodium- or protein-rich diets and type 2 diabetes mellitus, as well as pregnancy. Nephrotoxic agents and smoking also drive kidney cell loss. Intrinsic risk factors for CKD progression include poor nephron endowment because of prematurity at birth, nephropathic genetic variants, ageing, male sex and previous or concomitant kidney diseases. Care for lupus nephritis involves the control of all modifiable risk factors of CKD progression. In addition, remnant nephron overload can be reduced using early dual therapy with inhibitors of the renin-angiotensin system and sodium-glucose transporter-2, whereas further renoprotective drug interventions are underway. As patients with lupus nephritis are at risk of CKD progression, they would all benefit from interdisciplinary care to minimize the risk of kidney failure, cardiovascular disease and infections.

Nuclear receptor 4A1 ameliorates UUO-induced renal fibrosis by inhibiting the PI3K/AKT pathway

As an ultra-early response gene, Nuclear receptor 4A1 (NR4A1) has been reported to be involved in the development of various diseases through various pathological pathways, but its specific mechanism in chronic kidney disease (CKD) is unknown currently. Our study showed that the expression of NR4A1 was reduced in unilateral ureteral obstruction (UUO) mice and it could exacerbate UUO-induced renal pathological injury when knocked down NR4A1 in UUO mice. We found that the knockdown of NR4A1 could promote angiogenesis, renal inflammation, and cell apoptosis to aggravate renal fibrosis induced by UUO. As an agonist of NR4A1, Cytosporone B (Csn-B) could inhibit the renal fibrosis by attenuating angiogenesis, renal inflammation and cell apoptosis. In addition, the PI3K/AKT pathway was activated with NR4A1 knockdown in vivo and in vitro experiments. In conclusion, our study demonstrates that NR4A1 can ameliorate renal fibrosis. Furthermore, we speculate that its underlying mechanism may be related to the activation of PI3K/AKT pathway according to our present results.

Analysis of Risk Factors for Death from Melanoma and Genitourinary Diseases in Male Patients with Cutaneous Melanoma: A Cohort Propensity Score Matching Study

Objective

To analyze the influencing factors of male cutaneous melanoma (CM) patients dying from genitourinary diseases (GUD).

Methods

We searched the surveillance, epidemiology, and end results (SEER) database and extracted data on male CM patients according to the inclusion and exclusion criteria, including male patients whose cause of death was CM (cohort A) or GUD (cohort B). Comparisons between the two cohorts were performed before and after propensity score matching (PSM). An interaction analysis between age and year of diagnosis was also conducted. Cox regression analysis were performed to find the risk factors for death from GUD.

Results

Seven thousand seventy-eight CM patients were included, including 6415 (90.6%) in cohort A and 663 (9.4%) in cohort B. Compared with cohort A, cohort B patients were older (median age 74 ys. vs 65 ys.) and were more under the localized stage and had longer survival time no matter before or after PSM (all p<0.001). The stage was an inhibitory factor for cohort B (p <0.001). After PSM, only age and year of diagnosis were found to be cohort B's promoting factors (p<0.001). The interaction analysis showed that older patients diagnosed in later years (2009-2020) had a higher risk of dying from GUD compared to those diagnosed earlier (p<0.05). Patients with a later year of diagnosis (2009-2020) had a lower median survival time than patients with an earlier year of diagnosis (2000-2008) (p<0.001). When the patient's year of diagnosis was earlier (2000-2008), older patients (>75 ys.) had a higher risk of dying from GUD than younger patients (≤75 ys.) (p<0.001).

Conclusion

We first reported a significant interaction between age and year of diagnosis in male CM patients dying from GUD, highlighting the increased risk in older patients diagnosed more recently. We may pay attention to the possibility of dying from genitourinary diseases for CM patients.

Dual blockade of endothelin A and angiotensin II type 1 receptors with sparsentan as a novel treatment strategy to alleviate IgA nephropathy

INTRODUCTION

Although immunoglobulin A nephropathy (IgAN) had been discovered more than 50 years ago, 30-40% of IgAN patients still have primary glomerular disease that progresses to end-stage renal disease. However, various treatment strategies for IgAN have rapidly expanded in recent years to include endothelin (ET) receptor antagonists.

AREAS COVERED

In this review, we discuss the role of the ET-1/ETA receptor axis in the development of IgAN, especially focusing on the potential of sparsentan, a dual ET and angiotensin receptor antagonist as a novel therapy for IgAN.

EXPERT OPINION

Evaluation of the MEST-C score at the time of renal biopsy in IgAN is important in determining treatment strategies. If lesions are mainly in the acute phase, such as crescents, steroid therapy should be continued. However, if lesions are mainly in the chronic phase, such as glomerulosclerosis, sparsentan rather than steroid or angiotensin II receptor blocker alone may improve renal outcomes. Although further clinical studies are needed to back up these assumptions, appropriate combination of new drugs containing sparsentan and conventional drugs for IgAN treatment at the appropriate disease stage is expected to further inhibit the progression of renal damage.

Renal microRNA-144-3p is associated with transforming growth factor-β1-induced oxidative stress and fibrosis by suppressing the NRF2 pathway in hypertensive diabetic kidney disease

Chronic kidney disease (CKD) is a global health problem characterized by progressive renal fibrosis and excessive extracellular matrix deposition. Oxidative stress and epigenetic regulation, particularly through microRNAs (miRNAs), play crucial roles in the pathogenesis of CKD. In this study, we investigated the role of urinary miR-144-3p, which is upregulated in rats with CKD induced by diabetes and hypertension, in renal fibrosis progression, particularly its regulation of the nuclear factor erythroid-2-related factor 2 (NRF2) pathway. Our findings revealed elevated miR-144-3p levels and reduced NRF2 and target gene levels in kidney tissues of streptozotocin-treated spontaneously hypertensive rats. In vitro experiments demonstrated that miR-144-3p directly binds to the 3'-untranslated region of nrf2, suppressing the NRF2 pathway in renal tubular epithelial cells. Additionally, the profibrogenic factor transforming growth factor (TGF)-β1 increased miR-144-3p expression. TGF-β1-induced NRF2 suppression and reactive oxygen species elevation were found to be mediated through miR-144-3p upregulation. In vivo, cilostazol, an antiplatelet drug with an NRF2-activating effect, ameliorated renal injury in diabetic hypertensive rats by decreasing TGF-β1 and miR-144-3p levels while increasing NRF2 and its target gene levels in the kidneys. These findings highlight the potential therapeutic value of targeting the miR-144-3p/NRF2 pathway to attenuate CKD progression in hypertensive diabetic conditions.

Systemic Implications of Bullous Pemphigoid: Bridging Dermatology and Internal Medicine

Background: Bullous pemphigoid is an autoimmune bullous disease that frequently affects a large skin surface area, but it can also present in localized areas. It has been hypothesized that bullous pemphigoid affects the systemic functioning of different organs because inflammatory cells and cytokines circulate throughout numerous organs. Results: Recent clinical and experimental studies have revealed an association between bullous pemphigoid and systemic organ disorders. To avoid the emergence of systemic organ diseases, the significance of systemic treatment in cases of severe bullous pemphigoid should be emphasized. Conclusions: Here, we discuss the specific molecular processes underlying typical systemic organ inflammatory diseases associated with bullous pemphigoids.

Resistance physical exercise modulates metabolic adipokines, decreases body weight, and improves glomerular filtration in patients with chronic kidney disease in hemodialysis

Chronic kidney disease (CKD) is a condition characterized by abnormalities in kidney structure and function that persist for more than 3 months. It is estimated that more than 800 million people in the world have a diagnosis of CKD. To remove the harmful metabolic substances from the body, people with CKD need to perform hemodialysis. Due to their beneficial effects against a wide range of clinical conditions, physical exercise is considered a non-pharmacological therapy. This study aimed to evaluate the beneficial effects of resistance exercise during hemodialysis on metabolic adipokines, myokines, body weight, and glomerular filtration rate in patients living with CKD. Briefly, the blood samples were collected in two moments: immediately before the start of the resistance exercise protocol and 1 week after the end of the protocol. Resistance exercise protocol was performed thrice a week for 12 weeks and applied during hemodialysis sessions. Here, resistance exercise increases the circulating irisin (14.56%; p = 0.0112), handgrip strength (5.70%; p = 0.0036), glomerular filtration rate (25.9%; p = 0.022) and significantly decreases adiponectin (- 55.7%; p = 0.0044), body weight (- 3.7%; p = 0.0001), glucose (- 22%; p = 0.009), and albumin levels (- 9.55%; p = 0.0001). Conversely, leptin levels (- 10.9%; p = 0.38), iron (3.05%; p = 0.705), ferritin (3.24%; p = 0.880), hemoglobin (- 0.52%; p = 0.75), total cholesterol (7.9%; p = 0.19), LDL (- 9.99%; p = 0.15) and HDL (- 4.8%; p = 0.45), did not change after resistance exercise. Interestingly, 1,25 hydroxyvitamin D levels were significantly increased (14.5%; p = 0.01) following resistance exercise. Considering the effect of sex (males vs. females), we found that irisin levels increased in females but not in males after the resistance exercise protocol. Furthermore, handgrip strength and body weight were different, indicating that males had the highest strength and weight. We demonstrated that both males and females had lower albumin levels after the resistance exercise protocol. In conclusion, we suggest that resistance exercise has beneficial effects in the CKD population by modulating adipokines and metabolic myokines and therefore can be used as a non-pharmacological adjunctive therapy in CKD patients undergoing HD.

The contribution of the sphingosine 1-phosphate signaling pathway to chronic kidney diseases: recent findings and new perspectives

Chronic kidney disease (CKD) is a multifactorial condition with diverse etiologies, such as diabetes mellitus, hypertension, and genetic disorders, often culminating in end-stage renal disease (ESRD). A hallmark of CKD progression is kidney fibrosis, characterized by the excessive accumulation of extracellular matrix components, for which there is currently no effective anti-fibrotic therapy. Recent literature highlights the critical role of sphingosine 1-phosphate (S1P) signaling in CKD pathogenesis and renal fibrosis. This review provides an in-depth analysis of the latest findings on S1P metabolism and signaling in renal fibrosis and in specific CKDs, including diabetic nephropathy (DN), lupus nephritis (LN), focal segmental glomerulosclerosis (FSGS), Fabry disease (FD), and IgA nephropathy (IgAN). Emerging studies underscore the therapeutic potential of modulating S1P signaling with receptor modulators and inhibitors, such as fingolimod (FTY720) and more selective agents like ozanimod and cenerimod. Additionally, the current knowledge about the effects of established kidney protective therapies such as glucocorticoids and SGLT2 and ACE inhibitors on S1P signaling will be summarized. Furthermore, the review highlights the potential role of S1P as a biomarker for disease progression in CKD models, particularly in Fabry disease and diabetic nephropathy. Advanced technologies, including spatial transcriptomics, are further refining our understanding of S1P's role within specific kidney compartments. Collectively, these insights emphasize the need for continued research into S1P signaling pathways as promising targets for CKD treatment strategies.

Diminished nuclear-localized β-adrenoceptor signalling activates YAP to promote kidney fibrosis in diabetic nephropathy

BACKGROUND AND PURPOSE

Diabetic nephropathy (DN) is a leading cause of chronic kidney disease (CKD), which is characterized by mesangial matrix expansion that involves dysfunctional mesangial cells (MCs). However, the underlying mechanisms remain unclear. This study aims to delineate the spatiotemporal contribution of adrenergic signalling in diabetic kidney fibrosis to reveal potential therapeutic targets.

EXPERIMENTAL APPROACH

A model of diabetic nephropathy was induced by in db/db mice. Gene expression in kidneys was profiled by RNA-seq analyses, western blot and immunostaining. Subcellular-localized fluorescence resonance energy transfer (FRET) biosensors determined adrenergic signalling microdomains in MCs. Effects of oral rolipram, a phosphodiesterase 4 (PDE4) inhibitor, on the model were measured.

KEY RESULTS

Our model exhibited impaired kidney function with elevated expression of adrenergic and fibrotic genes, including Adrb1, PDEs, Acta2 and Tgfβ. RNA-seq analysis revealed that MCs with dysregulated YAP pathway were crucial to the extracellular matrix secretion in kidneys from diabetic nephropathy patients. In cultured MCs, TGF-β promoted profibrotic gene transcription, which was regulated by nuclear-localized β-adrenoceptor signalling. Mechanistically, TGF-β treatment diminished nuclear-specific cAMP signalling in MCs and reduced PKA-dependent phosphorylation of YAP, leading to its activation. In parallel, db/db mouse kidneys showed increased expressions of PDE4B and PDE4D. Treatment with oral rolipram alleviated kidney fibrosis in db/db mice.

CONCLUSION AND IMPLICATIONS

Diabetic nephropathy impaired nuclear-localized β1-adrenoceptor-cAMP signalling microdomain through upregulating PDE4 expression, promoting fibrosis in MCs via PKA dephosphorylation-dependent YAP activation. Our results suggest PDE4 inhibition as a promising strategy for alleviating kidney fibrosis in diabetic nephropathy.

Risk of renal impairment in atypical antipsychotics: a systematic review and meta-analysis

PURPOSE

Atypical antipsychotics are associated with several adverse effects including metabolic syndrome, weight gain, QTc interval prolongation, and extrapyramidal effects. This study aims to investigate the risk of renal impairment in patients receiving atypical antipsychotics.

METHODS

A systematic literature search was conducted via PubMed and Ovid SP and Web of Science to retrieve studies reporting the risk of renal impairment in patients receiving atypical antipsychotic treatment. The pooled risk ratio (RR) of renal impairment and the subgroup analysis was calculated using the random-effects generic inverse variance method in Cochrane Review Manager.

RESULTS

A total of 4 studies involving 514,710 patients (221, 873 patients on atypical antipsychotics/CKD and 292, 837 controls) were included in this meta-analysis. Patients on atypical antipsychotics exhibited an increased risk of renal impairment, with a pooled risk ratio of 1.34 (95%CI 1.23-1.47). Subgroup analysis demonstrated that atypical antipsychotic use was associated with an increased risk of both acute kidney injury (AKI) (RR 1.51, 95%CI 1.34-1.71) and chronic kidney disease (CKD) (RR: 1.23, 95%CI 1.12-1.35).

CONCLUSION

Patients receiving atypical antipsychotics have an increased risk of renal impairment. Quetiapine carries the highest risk of renal impairment encompassing both AKI and CKD.

Evaluation of cardiac remodeling in pediatric chronic kidney disease by cardiovascular magnetic resonance

BACKGROUND

Children with chronic kidney disease (CKD) are at high risk of cardiovascular disease. Cardiovascular magnetic resonance (CMR) is the reference method for assessing cardiac remodeling. To our knowledge, no study has reported a comprehensive analysis of left ventricular(LV) cardiac remodeling using CMR in different stages of pediatric CKD. This prospective case-control study aimed to investigate cardiac remodeling in pediatric CKD, using CMR, and determine its relationship with risk factors.

METHOD

CMR was performed in 124 children with CKD and 50 controls. The cardiac remodeling parameters included left ventricular mass index (LVMI), LV remodeling index (LVRI), and LV wall thickness. Univariable and multivariable analyses were performed to assess the cardiac remodeling risk factors.

RESULTS

Cardiac remodeling was observed in 35.5% (44/124) of children with CKD. The LVMI, LVRI, and LV wall thickness were higher in advanced stages of CKD (P < 0.05). In the CKD stage 1-2 group, a lower in the estimated glomerular filtration rate was an independent determinant of impaired LVMI (β = -0.425, P = 0.019) and LVRI (β = -0.319, P = 0.044). A higher protein to creatinine ratio(PCR) was independently associated with impaired LVRI (β = 0.429, P = 0.022). In the CKD stage 3-5 group, higher in systolic blood pressure (SBP) (β = 0.464, P = 0.005) and PCR (β = 0.852, P = 0.031) were independent determinants of impaired LVMI. Additionally, higher SBP was positively correlated with impaired LVRI(r = 0.599, P < 0.001). There was a trend toward more abnormal cardiac remodeling in the CKD stage 3-5 group with hypertension than those without.

CONCLUSION

Cardiac remodeling is prevalent in children with CKD, from an early stage. kidney markers are independently associated with cardiac remodeling. Hypertension increases the risk of cardiac remodeling in CKD stages 3-5. Strict BP control may help reverse or prevent remodeling.

Nuclear receptor 4A1 ameliorates renal fibrosis by inhibiting vascular endothelial growth factor A induced angiogenesis in UUO rats

INTRODUCTION

Angiogenesis is closely related to renal fibrosis; however, its basic mechanism remains unclear. In our study, we found that nuclear receptor 4A1 (NR4A1) inhibits vascular endothelial growth factor A (VEGFA)-induced angiogenesis, ameliorating renal fibrosis.

METHODS

We prepared a renal fibrosis animal model with unilateral ureteral obstruction (UUO) and NR4A1 knockdown UUO mice model, Using Human umbilical vein endothelial cells (HUVECs) to conduct all in vitro experiments. We then detected and analyzed the expression levels of NR4A1 and other genes related to angiogenesis and fibrosis.

RESULTS

The angiogenesis related genes, such as VEGFA, vascular endothelial growth factor receptor-2 (VEGFR-2), endoglin (CD105), as well as the expression of fibrosis related genes that included, α-smooth muscle actin (α-SMA), Vimentin, and Collagen I are all significantly increased in the UUO rat model. In addition, the expression of NR4A1 of the kidney tissue of UUO rats was significantly reduced. Therefore, according to the above results, we speculated that angiogenesis may exacerbate renal fibrosis and NR4A1 may repress renal fibrosis by inhibiting angiogenesis. To further verify the above results, we used VEGFA to stimulate HUVECs with (or without) overexpression or knockdown of NR4A1. The results showed that with prolonged stimulation using VEGFA, the expression of NR4A1 decreases. Overexpression of NR4A1 significantly inhibits the expression of related indicators of angiogenesis and renal fibrosis. Furthermore, knockdown of NR4A1 induces endothelial cell proliferation and migration; therefore, exacerbating angiogenesis and fibrosis. Finally, the results of NR4A1 knockdown UUO mice showed that knockdown of NR4A1 can aggravating kidney damage and induce the expression of angiogenesis and renal fibrosis related indicators, while UUO can significantly induce kidney damage, angiogenesis and renal fibrosis. When knockdown of NR4A1, renal kidney damage, angiogenesis and fibrosis becomes more severe than UUO. Thus, all of these results indicate that NR4A1 can ameliorate renal fibrosis by inhibiting angiogenesis.

CONCLUSIONS

NR4A1 can inhibit angiogenesis to ameliorate renal fibrosis.

Tissue-specific activation of insulin signaling as a potential target for obesity-related metabolic disorders

The incidence of obesity is rapidly increasing worldwide. Obesity-associated insulin resistance has long been established as a significant risk factor for obesity-related disorders such as type 2 diabetes and atherosclerosis. Insulin plays a key role in systemic glucose metabolism, with the liver, skeletal muscle, and adipose tissue as the major acting tissues. Insulin receptors and the downstream insulin signaling-related molecules are expressed in various tissues, including vascular endothelial cells, vascular smooth muscle cells, and monocytes/macrophages. In obesity, decreased insulin action is considered a driver for associated disorders. However, whether insulin action has a positive or negative effect on obesity-related disorders depends on the tissue in which it acts. While an enhancement of insulin signaling in the liver increases hepatic fat accumulation and exacerbates dyslipidemia, enhancement of insulin signaling in adipose tissue protects against obesity-related dysfunction of various organs by increasing the capacity for fat accumulation in the adipose tissue and inhibiting ectopic fat accumulation. Thus, this "healthy adipose tissue expansion" by enhancing insulin sensitivity in adipose tissue, but not in the liver, may be an effective therapeutic strategy for obesity-related disorders. To effectively address obesity-related metabolic disorders, the mechanisms of insulin resistance in various tissues of obese patients must be understood and drugs that enhance insulin action must be developed. In this article, we review the potential of interventions that enhance insulin signaling as a therapeutic strategy for obesity-related disorders, focusing on the molecular mechanisms of insulin action in each tissue.

Distinct profiles of bile acid metabolism caused by gut microbiota in kidney transplantation recipients revealed by 16S rRNA gene sequencing

The present study sought to characterise the gut microbiota of subjects with kidney transplantation and healthy control to identify the distinct gut microbiota and analyse their potential function. We found that gut microbiota abundance had significant differences in subjects between the two groups. Line Discriminant Analysis (LDA) Effect Size (LEfSe) analysis showed that the bacterial taxa were differentially represented between the two groups, and the potential biomarkers at different taxonomic levels in kidney transplant recipients were Streptococcus, Enterococcaceae, and Ruminococcus. Phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) Functional Inference analyses suggested that the difference in gut microbiota between the two groups was correlated with bile acid metabolism. In conclusion, gut microbiota abundance is different between the two groups, which is related to bile acid metabolism, and may influence the metabolic homeostasis of allograft recipients.

The global status of nursing research on hemodialysis: A bibliometric and visualized analysis

BACKGROUND

Hemodialysis (HD)-related nursing research has been growing over the past 2 decades, providing critical insights into improving patient care and outcomes. This study aimed to visualize the hotspots and emerging frontiers in HD-related nursing research, offering valuable references for future studies.

METHODS

A bibliometric analysis was conducted on publications related to HD nursing research from the Web of Science Core Collection database, spanning the years 2002 to 2023, and the characteristics of literature such as authors, co-cited authors, countries, research institutions, journal distribution, keywords, and cited literature were visually analyzed using CiteSpace and VOSviewer.

RESULTS

A total of 1019 publications were included in this study. The major contributors to this field were the United States, China, and Australia. The University of Sao Paulo emerged as the most prolific institution. The principal contributors were the Nephrology Nursing Journal, followed by Journal of Renal Care and Journal of Clinical Nursing. The top 5 co-occurrence keywords included HD, quality of life, dialysis, chronic kidney disease, and end-stage renal disease. The burst detection of keywords showed that current research frontier trends were pain and validation. The top 5 largest clusters of cited references included research on systematic review research, nurse-led disease management program, family caregiver, end-stage renal disease, and self-care intervention.

CONCLUSION

This study reveals productive authors, countries and institutions, research hotspots, and trends of HD-related nursing research over the past 2 decades, offering a comprehensive overview of this field worldwide.

Does the Composition of Gut Microbiota Affect Chronic Kidney Disease? Molecular Mechanisms Contributed to Decreasing Glomerular Filtration Rate

Chronic kidney disease (CKD) is a very prevalent and insidious disease, particularly with initially poorly manifested symptoms that progressively culminate in the manifestation of an advanced stage of the condition. The gradual impairment of kidney function, particularly decreased filtration capacity, results in the retention of uremic toxins and affects numerous molecular mechanisms within the body. The dysbiotic intestinal microbiome plays a crucial role in the accumulation of protein-bound uremic toxins such as p-cresol (pC), indoxyl sulfate (IS), and p-cresyl sulfate (p-CS) through the ongoing fermentation process. The described phenomenon leads to an elevated level of oxidative stress and inflammation, subsequently resulting in tissue damage and complications, particularly an increase in cardiovascular risk, representing the predominant cause of mortality in chronic kidney disease (CKD). Therefore, exploring methods to reduce uremic toxins is currently a pivotal therapeutic strategy aimed at reducing the risk of organ damage in patients with chronic kidney disease (CKD). This review aims to summarize recent discoveries on modifying the composition of the intestinal microbiota through the introduction of special probiotic and synbiotic supplements for CKD therapy. The potential to connect the gut microbiota with CKD opens the possibility for further extensive research in this area, which could lead to the incorporation of synbiotics and probiotics into the fundamental treatment and prevention of CKD.

Kidney Injury Evoked by Fine Particulate Matter: Risk Factor, Causation, Mechanism and Intervention Study

Fine particulate matter (PM2.5) is suggested to pose a severe risk to the kidneys by inducing functional degradation and chronic kidney diseases (CKD). This study aims to explore the nephrotoxicity of PM2.5 exposure and the underlying mechanism. Herein, based on the UK Biobank, it is found that per interquartile range (IQR) increase in PM2.5 is associated with a 6% (95% CI: 1%-11%), 7% (95% CI: 3%-11%), 9% (95% CI: 4%-13%), 11% (95% CI: 9%-13%), and 10% (95% CI: 8%-12%) increase in the risk of nephritis, hydronephrosis, kidney stone, acute renal failure, and CKD, respectively. In experimental study, noticeable kidney injury, which is the initiation of kidney diseases, is observed with PM2.5 exposure in C57BL/6N mice (n = 8), accompanied with oxidative stress, autophagy and pyroptosis. In vitro, HK-2 cells with PM2.5-stimulation exhibit tubulopathy, increased reactive oxygen species (ROS) generation and activated pyroptosis and autophagy. All changes are abolished by ROS scavenger of N-acetyl-L-cysteine (NAC) both in vivo and in vitro. In conclusion, the study provides evidence showing that PM2.5 exposure is associated with 5 kinds of kidney diseases by directly inducing nephrotoxicity, in which ROS may be the potential target by triggering autophagy and pyroptosis.

Radix Astragali and Its Representative Extracts for Diabetic Nephropathy: Efficacy and Molecular Mechanism

Diabetic nephropathy (DN) is a common microvascular complication of diabetes mellitus (DM). Radix Astragali (RA), a frequently used Chinese herbal medicine in the Leguminosae family, Astragalus genus, with its extracts, has been proven to be effective in DN treatment both in clinical practice and experimental studies. RA and its extracts can reduce proteinuria and improve renal function. They can improve histopathology changes including thickening of the glomerular basement membrane, mesangial cell proliferation, and injury of endothelial cells, podocytes, and renal tubule cells. The mechanisms mainly benefited from antioxidative stress which involves Nrf2/ARE signaling and the PPARγ-Klotho-FoxO1 axis; antiendoplasmic reticulum stress which involves PERK-ATF4-CHOP, PERK/eIF2α, and IRE1/XBP1 pathways; regulating autophagy which involves SIRT1/NF-κB signaling and AMPK signaling; anti-inflammation which involves IL33/ST2 and NF-κB signaling; and antifibrosis which involves TGF-β1/Smads, MAPK (ERK), p38/MAPK, JNK/MAPK, Wnt/β-catenin, and PI3K/AKT/mTOR signaling pathways. This review focuses on the clinical efficacy and the pharmacological mechanism of RA and its representative extracts on DN, and we further document the traditional uses of RA and probe into the TCM theoretical basis for its application in DN.

Association of triglyceride-glucose-body mass index with all-cause and cardiovascular mortality among individuals with chronic kidney disease

There is still a paucity of research on the relationship between triglyceride-glucose-body mass index (TyG-BMI) and long-term all-cause and cardiovascular disease (CVD) mortality in patients with chronic kidney disease (CKD). The objective of this study was to explore the relationship between the TyG-BMI index and mortality rate and to determine valuable predictive factors for the survival status of this population. Data were obtained from the National Health and Nutrition Examination Survey (NHANES 2001-2018) and the National Death Index (NDI). We used multivariate Cox regression and restricted cubic spline (RCS) to analyze the link between the TyG-BMI index and all-cause and CVD mortality. Subgroup analysis was conducted according to age, gender, race, education and poverty. In addition, receiver operating characteristic (ROC) curves were utilized to assess the differentiation of the TyG-BMI index in predicting mortality. A total of 3089 individuals were enrolled. Over a median follow-up period of 81 months, 1097 individuals passed away. The RCS analysis revealed a U-shaped link between the TyG-BMI index and all-cause and CVD mortality. The ROC curve indicated that the TyG-BMI index has a stronger diagnostic effect than the TyG index. Subgroup analysis results demonstrated that the TyG-BMI index was more significantly correlated with all-cause and CVD mortality rates in elderly patients. In the American population, a U-shaped association was discovered between the baseline TyG-BMI index and all-cause and cardiovascular mortality rates in CKD patients. The thresholds for all-cause and CVD mortality were found to be 299.31 and 294.85, respectively.

Counteracting TGM2 by a Fibroin peptide ameliorated Adriamycin-induced nephropathy via regulation of lipid metabolism through PANX1-PPAR α/PANK1 pathway

Peptide drug discovery for the treatment of chronic kidney disease (CKD) has attracted much attention in recent years due to the urge to find novel drugs and mechanisms to delay the progression of the disease. In this study, we identified a novel short peptide (named YR-7, primary sequence 'YEVEDYR') from the natural Fibroin protein, and demonstrated that it significantly alleviated pathological renal changes in ADR-induced nephropathy. PANX1 was identified as the most notably upregulated component by RNA-sequencing. Further analysis showed that YR-7 alleviated the accumulation of lipid droplets via regulation of the lipid metabolism-related proteins PPAR α and PANK1. Using chemical proteomics, fluorescence polarization, microscale thermophoresis, surface plasmon resonance, and molecular docking, YR-7 was proven to directly bind to β-barrel domains of TGM2 protein to inhibit lipid accumulation. TGM2 knockdown in vivo increased the protein levels of PPAR α and PANK1 while decreased the levels of fibrotic-related proteins to alleviate nephropathy. In vitro, overexpression TGM2 reversed the protective effects of YR-7. Co-immunoprecipitation indicated that TGM2 interacted with PANX1 to promote lipid deposition, and pharmacological inhibition or knockdown of PANX1 decreased the levels of PPAR α and PANK1 induced by ADR. Taken together, our findings revealed that TGM2-PANX1 interaction in promoting lipid deposition may be a new signaling in promoting ADR-induced nephropathy. And a novel natural peptide could ameliorate renal fibrosis through TGM2-PANX1-PPAR α/PANK1 pathway, which highlight the potential of it in the treatment of CKD.

Validation of a Clinical Scale for Early Detection of Infections at the Exit Site of Central Venous Catheters for Hemodialysis

Introduction

Exit-site infections (ESI) of central venous catheters for hemodialysis (CVC-HD) has been associated with early catheter removal and an increased risk of CVC-HD related bacteremia. No specific clinical scales to predict ESI have previously been validated.

Methods

A multicenter prospective cohort study was performed to validate the proposed scale, which is based on the following 5 signs and symptoms: (i) pain at exit site during interdialytic period; (ii) hyperemia or erythema ≥2 cm from exit site; (iii) inflammation, induration, or swelling at exit site; (iv) fever ≥38 °C not attributable to other causes, and (v) obvious abscess or purulent exudate at the exit site. Adult patients with a tunneled CVC-HD for at least 1 month after insertion has been included. During each hemodialysis session, the exit site was assessed with the proposed scale by nurses. If any item was present, a pericatheter skin swab culture was collected: positive results were gold standard. The scale was validated using receiver operating characteristic (ROC) curves and logistic regression analysis. For this purpose, the logit function was applied, and the ESI probability calculated, as elogit ESI/1 + elogit ESI.

Results

Three hundred thirty-seven CVC-HDs from 310 patients were analyzed, producing 515 cultures (117 infected and 398 healthy). The final version of the scale includes the following 3 signs and symptoms, which present the greatest predictive capacity: (i) pain at exit site during interdialytic period, (ii) hyperemia or erythema ≥2 cm from exit site, and (iii) abscess or purulent exudate at the exit site. The final version generated an area under the ROC curve (AUC) of 88.3% (95% confidence interval [CI]: 85.2%-91%; P < 0.001), Youden index 0.7557 ≈ 1, sensitivity 80.34% (95% CI: 71.36%-87.71%) and specificity 95.23% (95% CI: 92.73%-97%).

Conclusions

The validation shows that the scale has good predictive properties, detecting approximately 90% of ESI with very acceptable validity parameters.

The added value of superb microvascular imaging for renal cortical thickness measurement in chronic kidney disease

PURPOSE

The aim of this study was to evaluate renal parenchymal thickness and renal cortical thickness measurements on brightness mode ultrasound (B-mode US) and B-mode US + Superb Microvascular Imaging (SMI) technique, comparing with computed tomography (CT) or magnetic resonance imaging (MRI) serving as a reference standard.

METHODS

Renal parenchymal thickness and renal cortical thickness measurements were obtained from B-mode US, B-mode US + SMI, and CT/MRI in a group of healthy subjects and a group of patients with chronic kidney disease (CKD). The mean differences and correlations of renal parenchymal thickness and renal cortical thickness were analyzed using dependent pair t-test and Pearson's correlation, respectively.

RESULTS

The mean difference in renal cortical thickness measurements between B-mode US + SMI and CT/MRI was lower than the mean difference between B-mode US alone and CT/MRI. Additionally, renal cortical thickness measured using B-mode US + SMI showed a stronger correlation with values obtained from CT/MRI than values measured using standard B-mode US alone.

CONCLUSION

The measurement of renal cortical thickness by B-mode US + SMI is more accurate than that by B-mode US alone.

Oral Health in Children with Chronic Kidney Disease, Hemodialysis, and Renal Transplantation: A Comprehensive Narrative Review of the Oral Manifestations and Dental Implications

Chronic kidney disease (CKD) in children presents multifaceted challenges, impacting various aspects of health, including oral health. This narrative review provides a comprehensive synthesis of literature focusing on the oral health status of pediatric CKD patients, encompassing oral manifestations, dental considerations, and management challenges associated with hemodialysis and kidney transplantation. A comprehensive search strategy was employed, utilizing databases such as PubMed, Scopus, Web of Science, and Google Scholar, to identify relevant literature on oral manifestations in children with CKD, including those undergoing hemodialysis or renal transplantation. Search terms were carefully selected to capture studies examining enamel hypoplasia, dental caries, delayed tooth eruption, gingival diseases, periodontal diseases, radiographic alterations, craniofacial development, dry mouth, and changes in the oral mucosa. Our narrative review meticulously selected articles through a systematic process. Ultimately, 12 studies meeting the inclusion criteria were included in the review. Relevant data from each included study were independently extracted and synthesized, focusing on oral manifestations and their implications in pediatric CKD patients. The synthesized findings were organized and presented in a structured manner within the review article, considering their clinical implications and informing recommendations for dental management of children with CKD. This article highlights the importance of a coordinated effort between nephrologists, dentists, and other healthcare professionals in providing holistic care for pediatric CKD patients. A comprehensive understanding of the oral health status of these children, along with proactive dental management strategies, contributes to improved overall health outcomes and a better quality of life. This review aims to serve as a valuable resource for the oral healthcare providers involved in the care of pediatric CKD patients.

Enzymes in Addressing Hypoxia for Biomaterials Engineering

Oxygen is essential for normal cellular functions. Hypoxia impacts various cellular processes, such as metabolism, growth, proliferation, angiogenesis, metastasis, tumorigenesis, microbial infection, and immune response, mediated by hypoxia-inducible factors (HIFs). Hypoxia contributes to the progression and development of cancer, cardiovascular diseases, metabolic disorders, kidney diseases, and infections. The potential alleviation of hypoxia has been explored through the enzymatic in situ decomposition of hydrogen peroxide, leading to the generation of oxygen. However, challenges such as limited stability restrict the effectiveness of enzymes such as catalase in biomedical and in vivo applications. To overcome these limitations, targeted delivery of the enzymes has been proposed. This review offers a critical comparison of i) current approaches to enhance the in vivo stability of catalase; and ii) the structure, mechanism of action, and kinetics of catalase and catalase-like nanozymes.

The role of intercellular communication in diabetic nephropathy

Diabetic nephropathy, a common and severe complication of diabetes, is the leading cause of end-stage renal disease, ultimately leading to renal failure and significantly affecting the prognosis and lives of diabetics worldwide. However, the complexity of its developmental mechanisms makes treating diabetic nephropathy a challenging task, necessitating the search for improved therapeutic targets. Intercellular communication underlies the direct and indirect influence and interaction among various cells within a tissue. Recently, studies have shown that beyond traditional communication methods, tunnel nanotubes, exosomes, filopodial tip vesicles, and the fibrogenic niche can influence pathophysiological changes in diabetic nephropathy by disrupting intercellular communication. Therefore, this paper aims to review the varied roles of intercellular communication in diabetic nephropathy, focusing on recent advances in this area.

Higher Circulating Neutrophil Counts Is Associated with Increased Risk of All-Cause Mortality and Cardiovascular Disease in Patients with Diabetic Kidney Disease

BACKGROUND

Accumulating evidence has suggested the pathogenic roles of chronic inflammation and neutrophils in diabetic kidney disease (DKD). This study investigated the relationship between neutrophils, all-cause, and cardiovascular disease (CVD) mortality in type 2 diabetes mellitus (T2DM) patients with DKD.

METHODS

We used data from the National Health and Nutrition Examination Surveys (NHANES) from 2005 to 2020 to investigate the relationship between circulating neutrophils counts, kidney function indices, all-cause, and CVD mortality in adult T2DM patients with DKD. Clinical predictive models and risk scores for long-term mortality were constructed.

RESULTS

44,332 patients [8034 with T2DM and 36,323 without T2DM] were included. Two thousand two hundred twenty patients had DKD, and 775 died (31.5% related to CVD) during a follow-up of 6.18 (range: 5.94-6.42) years. Higher neutrophil counts (Quartile 4, Q4) were associated with increased all-cause and CVD mortality [HR 1.73 (95% CI 1.34-2.25) and 1.81 (95% CI 1.14-2.89), respectively, p < 0.0001 and 0.01]. Neutrophil counts in Q4 showed a positive correlation with urine albumin-creatinine ratio (UACR) but a negative association with eGFR (p < 0.01 for all). Clinical predictive models incorporating neutrophil counts showed satisfactory performance in forecasting 5-year and 10-year CVD mortality-free survival (ROC AUC 0.824 and 0.842, respectively), and the nomogram-predicted survival demonstrated good concordance with observed survival.

CONCLUSIONS

Higher levels of circulating neutrophil counts show a significant correlation with renal abnormalities and higher all-cause and CVD mortality in T2DM patients with DKD. The novel clinical predictive models and risk scores incorporating neutrophil counts may facilitate stratification and, hence, risk factor management in DKD patients.

Reduction in Renal Interstitial Fibrosis in Aged Male Mice by Intestinal Microbiota Rejuvenation

INTRODUCTION

Renal interstitial fibrosis is an important pathological basis for kidney ageing and the progression of ageing nephropathy. In the present research, we established an aged mouse model of faecal microbiota transplantation (FMT), identified the rejuvenation features of the kidney in aged male mice, and preliminarily analysed the possible mechanism by which the rejuvenation of the intestinal microbiota reduces renal interstitial fibrosis and delays senescence in aged male mice.

METHODS

We established an aged male mice model that was treated with FMT (FMT-Old) and a normal aged male mice control group (Old). Differentially expressed cytokines were identified using a cytokine array, and changes in protein expression related to signal transduction pathways in renal tissues were detected using a signalling pathway array. Senescence-associated β-galactosidase and Masson staining were performed to observe the degrees of renal senescence and tubule interstitial fibrosis. Immunohistochemistry was utilized to detect changes in the expression of the ageing markers p53 and p21 and the inflammation-related protein nuclear factor (NF-κB) subunit (RelA/p65).

RESULTS

The pathological features of renal senescence in the FMT-Old group were significantly alleviated, and the levels of the ageing indicators p53 and p21 were decreased (p < 0.05). Ingenuity Pathway Analysis revealed that six differentially expressed cytokines, MIP-3β (CCL-19), E-selectin (SELE), Fas ligand (Fas L/FASLG), CXCL-11 (I-TAC), CXCL-1 and CCL-3 (MIP-1α) were related to a common upstream regulatory protein, RelA/p65, and the expression of this protein was significantly different between groups according to the signalling pathway array.

CONCLUSION

Our findings suggest that the intestinal microbiota regulates the renal microenvironment by reducing immune inflammatory responses through the inhibition of the NF-κB signalling pathway, thereby delaying renal senescence in aged male mice.

Near-Infrared Forearm Vascular Width Calculation Using Radius Estimation of Tangent Circle

In response to the analysis of the functional status of forearm blood vessels, this paper fully considers the orientation of the vascular skeleton and the geometric characteristics of blood vessels and proposes a blood vessel width calculation algorithm based on the radius estimation of the tangent circle (RETC) in forearm near-infrared images. First, the initial infrared image obtained by the infrared camera is preprocessed by image cropping, contrast stretching, denoising, enhancement, and initial segmentation. Second, the Zhang-Suen refinement algorithm is used to extract the vascular skeleton. Third, the Canny edge detection method is used to perform vascular edge detection. Finally, a RETC algorithm is developed to calculate the vessel width. This paper evaluates the accuracy of the proposed RETC algorithm, and experimental results show that the mean absolute error between the vessel width obtained by our algorithm and the reference vessel width is as low as 0.36, with a variance of only 0.10, which can be significantly reduced compared to traditional calculation measurements.

Glucosylceramide synthase modulation ameliorates murine renal pathologies and promotes macrophage effector function in vitro

While significant advances have been made in understanding renal pathophysiology, less is known about the role of glycosphingolipid (GSL) metabolism in driving organ dysfunction. Here, we used a small molecule inhibitor of glucosylceramide synthase to modulate GSL levels in three mouse models of distinct renal pathologies: Alport syndrome (Col4a3 KO), polycystic kidney disease (Nek8jck), and steroid-resistant nephrotic syndrome (Nphs2 cKO). At the tissue level, we identified a core immune-enriched transcriptional signature that was shared across models and enriched in human polycystic kidney disease. Single nuclei analysis identified robust transcriptional changes across multiple kidney cell types, including epithelial and immune lineages. To further explore the role of GSL modulation in macrophage biology, we performed in vitro studies with homeostatic and inflammatory bone marrow-derived macrophages. Cumulatively, this study provides a comprehensive overview of renal dysfunction and the effect of GSL modulation on kidney-derived cells in the setting of renal dysfunction.

Multiomic profiling of new-onset kidney function decline: insights from the STANISLAS study cohort with a 20-year follow-up

Background

Identifying the biomarkers associated with new-onset glomerular filtration rate (GFR) decrease in an initially healthy population could offer a better understanding of kidney function decline and help improving patient management.

Methods

Here we described the proteomic and transcriptomic footprints associated with new-onset kidney function decline in an initially healthy and well-characterized population with a 20-year follow-up. This study was based on 1087 individuals from the familial longitudinal Suivi Temporaire Annuel Non-Invasif de la Santé des Lorrains Assurés Sociaux (STANISLAS) cohort who attended both visit 1 (from 1993 to 1995) and visit 4 (from 2011 to 2016). New-onset kidney function decline was approached both in quantitative (GFR slope for each individual) and qualitative (defined as a decrease in GFR of >15 ml/min/1.7 m2) ways. We analysed associations of 445 proteins measured both at visit 1 and visit 4 using Olink Proseek® panels and 119 765 genes expressions measured at visit 4 with GFR decline. Associations were assessed using multivariable models. The Bonferroni correction was applied.

Results

We found several proteins (including PLC, placental growth factor (PGF), members of the tumour necrosis factor receptor superfamily), genes (including CCL18, SESN3), and a newly discovered miRNA-mRNA pair (MIR1205-DNAJC6) to be independently associated with new-onset kidney function decline. Complex network analysis highlighted both extracellular matrix and cardiovascular remodelling (since visit 1) as well as inflammation (at visit 4) as key features of early GFR decrease.

Conclusions

These findings lay the foundation to further assess whether the proteins and genes herein identified may represent potential biomarkers or therapeutic targets to prevent renal function impairment.

Acute kidney injury during autologous stem cell transplantation in light chain amyloidosis with kidney involvement and their impact on prognosis

Acute kidney injury (AKI) is a complication related to important organ dysfunction during autologous stem cell transplantation (ASCT) in light chain (AL) amyloidosis. This study aims to validate the risk factors of AKI during different periods of ASCT and the impact of AKI on long-term outcomes. 302 patients with AL amyloidosis and kidney involvement who underwent ASCT were included. The procedures from stem cell mobilization to 30 days after transplantation were categorized into four periods: Period 0 (stem cell mobilization and harvest), Period 1 (preparation), Period 2 (conditioning and transplantation), and Period 3 (engraftment). The incidence of AKI during ASCT was 27.15% (0.66% in Period 0, 6.62% in Period 1, 15.23% in Period 2, and 6.95% in Period 3). The major causes of AKI were capillary leak syndrome in Period 0, ganciclovir or sulfamethoxazole/trimethoprim in Period 1, high-dose melphalan in Period 2, and engraftment syndrome in Period 3. AKI in different periods had distinct risk factors and predictive models. AKI was a risk factor for both kidney survival and overall survival (OS). Even recovered AKI reduced 10-year kidney survival from 91.7% to 68.4% (p = 0.002) and 10-year OS from 91.1% to 77.7% (p = 0.005).

Membranous translocation of murine double minute 2 promotes the increased renal tubular immunogenicity in ischemia-reperfusion-induced acute kidney injury

Kidneys from donors with prolonged warm and cold ischemia are prone to posttransplant T cell-mediated rejection (TCMR) due to ischemia-reperfusion injury (IRI). However, the precise mechanisms still remain obscure. Renal tubular epithelial cells (TECs) are the main target during IRI. Meanwhile, we have previously reported that murine double minute 2 (MDM2) actively participates in TEC homeostasis during IRI. In this study, we established a murine model of renal IRI and a cell model of hypoxia-reoxygenation by culturing immortalized rat renal proximal tubule cells (NRK-52E) in a hypoxic environment for different time points followed by 24 h of reoxygenation and incubating NRK-52E cells in a chemical anoxia-recovery environment. We found that during renal IRI MDM2 expression increased on the membrane of TECs and aggregated mainly on the basolateral side. This process was accompanied by a reduction of a transmembrane protein, programmed death ligand 1 (PD-L1), a coinhibitory second signal for T cells in TECs. Using mutant plasmids of MDM2 to anchor MDM2 on the cell membrane or nuclei, we found that the upregulation of membrane MDM2 could promote the ubiquitination of PD-L1 and lead to its ubiquitination-proteasome degradation. Finally, we set up a coculture system of TECs and CD4+ T cells in vitro; our results revealed that the immunogenicity of TECs was enhanced during IRI. In conclusion, our findings suggest that the increased immunogenicity of TECs during IRI may be related to ubiquitinated degradation of PD-L1 by increased MDM2 on the cell membrane, which consequently results in T-cell activation and TCMR.NEW & NOTEWORTHY Ischemic acute kidney injury (AKI) donors can effectively shorten the waiting time for kidney transplantation but increase immune rejection, especially T cell-mediated rejection (TCMR), the mechanism of which remains to be elucidated. Our study demonstrates that during ischemia-reperfusion injury (IRI), the translocation of tubular murine double minute 2 leads to basolateral programmed death ligand 1 degradation, which ultimately results in the occurrence of TCMR, which may provide a new therapeutic strategy for preventing AKI donor-associated TCMR.

Diffusion tensor MRI is sensitive to fibrotic injury in a mouse model of oxalate-induced chronic kidney disease

Chronic kidney disease (CKD) is characterized by inflammation and fibrosis in the kidney. Renal biopsies and estimated glomerular filtration rate (eGFR) remain the standard of care, but these endpoints have limitations in detecting the stage, progression, and spatial distribution of fibrotic pathology in the kidney. MRI diffusion tensor imaging (DTI) has emerged as a promising noninvasive technology to evaluate renal fibrosis in vivo both in clinical and preclinical studies. However, these imaging studies have not systematically identified fibrosis particularly deeper in the kidney where biopsy sampling is limited, or completed an extensive analysis of whole organ histology, blood biomarkers, and gene expression to evaluate the relative strengths and weaknesses of MRI for evaluating renal fibrosis. In this study, we performed DTI in the sodium oxalate mouse model of CKD. The DTI parameters fractional anisotropy, apparent diffusion coefficient, and axial diffusivity were compared between the control and oxalate groups with region of interest (ROI) analysis to determine changes in the cortex and medulla. In addition, voxel-based analysis (VBA) was implemented to systematically identify local regions of injury over the whole kidney. DTI parameters were found to be significantly different in the medulla by both ROI analysis and VBA, which also spatially matched with collagen III immunohistochemistry (IHC). The DTI parameters in this medullary region exhibited moderate to strong correlations with histology, blood biomarkers, hydroxyproline, and gene expression. Our results thus highlight the sensitivity of DTI to the heterogeneity of renal fibrosis and importance of whole kidney noninvasive imaging.NEW & NOTEWORTHY Chronic kidney disease (CKD) can be characterized by inflammation and fibrosis of the kidney. Although standard of care methods have been limited in scope, safety, and spatial distribution, MRI diffusion tensor imaging (DTI) has emerged as a promising noninvasive technology to evaluate renal fibrosis in vivo. In this study, we performed DTI in an oxalate mouse model of CKD to systematically identify local kidney injury. DTI parameters strongly correlated with histology, blood biomarkers, hydroxyproline, and gene expression.

Systemic aging fuels heart failure: Molecular mechanisms and therapeutic avenues

Systemic aging influences various physiological processes and contributes to structural and functional decline in cardiac tissue. These alterations include an increased incidence of left ventricular hypertrophy, a decline in left ventricular diastolic function, left atrial dilation, atrial fibrillation, myocardial fibrosis and cardiac amyloidosis, elevating susceptibility to chronic heart failure (HF) in the elderly. Age-related cardiac dysfunction stems from prolonged exposure to genomic, epigenetic, oxidative, autophagic, inflammatory and regenerative stresses, along with the accumulation of senescent cells. Concurrently, age-related structural and functional changes in the vascular system, attributed to endothelial dysfunction, arterial stiffness, impaired angiogenesis, oxidative stress and inflammation, impose additional strain on the heart. Dysregulated mechanosignalling and impaired nitric oxide signalling play critical roles in the age-related vascular dysfunction associated with HF. Metabolic aging drives intricate shifts in glucose and lipid metabolism, leading to insulin resistance, mitochondrial dysfunction and lipid accumulation within cardiomyocytes. These alterations contribute to cardiac hypertrophy, fibrosis and impaired contractility, ultimately propelling HF. Systemic low-grade chronic inflammation, in conjunction with the senescence-associated secretory phenotype, aggravates cardiac dysfunction with age by promoting immune cell infiltration into the myocardium, fostering HF. This is further exacerbated by age-related comorbidities like coronary artery disease (CAD), atherosclerosis, hypertension, obesity, diabetes and chronic kidney disease (CKD). CAD and atherosclerosis induce myocardial ischaemia and adverse remodelling, while hypertension contributes to cardiac hypertrophy and fibrosis. Obesity-associated insulin resistance, inflammation and dyslipidaemia create a profibrotic cardiac environment, whereas diabetes-related metabolic disturbances further impair cardiac function. CKD-related fluid overload, electrolyte imbalances and uraemic toxins exacerbate HF through systemic inflammation and neurohormonal renin-angiotensin-aldosterone system (RAAS) activation. Recognizing aging as a modifiable process has opened avenues to target systemic aging in HF through both lifestyle interventions and therapeutics. Exercise, known for its antioxidant effects, can partly reverse pathological cardiac remodelling in the elderly by countering processes linked to age-related chronic HF, such as mitochondrial dysfunction, inflammation, senescence and declining cardiomyocyte regeneration. Dietary interventions such as plant-based and ketogenic diets, caloric restriction and macronutrient supplementation are instrumental in maintaining energy balance, reducing adiposity and addressing micronutrient and macronutrient imbalances associated with age-related HF. Therapeutic advancements targeting systemic aging in HF are underway. Key approaches include senomorphics and senolytics to limit senescence, antioxidants targeting mitochondrial stress, anti-inflammatory drugs like interleukin (IL)-1β inhibitors, metabolic rejuvenators such as nicotinamide riboside, resveratrol and sirtuin (SIRT) activators and autophagy enhancers like metformin and sodium-glucose cotransporter 2 (SGLT2) inhibitors, all of which offer potential for preserving cardiac function and alleviating the age-related HF burden.

A Comprehensive Physiologically Based Pharmacokinetic Model for Predicting Vildagliptin Pharmacokinetics: Insights into Dosing in Renal Impairment

Physiologically based pharmacokinetic (PBPK) modeling is of great importance in the field of medicine. This study aims to construct a PBPK model, which can provide reliable drug pharmacokinetic (PK) predictions in both healthy and chronic kidney disease (CKD) subjects. To do so, firstly a review of the literature was thoroughly conducted and the PK information of vildagliptin was collected. PBPK modeling software, PK-Sim®, was then used to build and assess the IV, oral, and drug-specific models. Next, the average fold error, visual predictive checks, and predicted/observed ratios were used for the assessment of the robustness of the model for all the essential PK parameters. This evaluation demonstrated that all PK parameters were within an acceptable limit of error, i.e., 2 fold. Also to display the influence of CKD on the total and unbound AUC (the area under the plasma concentration-time curve) and to make modifications in dose, the analysis results of the model on this aspect were further examined. This PBPK model has successfully depicted the variations of PK of vildagliptin in healthy subjects and patients with CKD, which can be useful for medical practitioners in dosage optimization in renal disease patients.

Machine Learning for Predicting Chronic Renal Disease Progression in COVID-19 Patients with Acute Renal Injury: A Feasibility Study

This study aimed to determine the feasibility of applying machine-learning methods to assess the progression of chronic kidney disease (CKD) in patients with coronavirus disease (COVID-19) and acute renal injury (AKI). The study was conducted on patients aged 18 years or older who were diagnosed with COVID-19 and AKI between April 2020 and March 2021, and admitted to a second-level hospital in Mérida, Yucatán, México. Of the admitted patients, 47.92% died and 52.06% were discharged. Among the discharged patients, 176 developed AKI during hospitalization, and 131 agreed to participate in the study. The study's results indicated that the area under the receiver operating characteristic curve (AUC-ROC) for the four models was 0.826 for the support vector machine (SVM), 0.828 for the random forest, 0.840 for the logistic regression, and 0.841 for the boosting model. Variable selection methods were utilized to enhance the performance of the classifier, with the SVM model demonstrating the best overall performance, achieving a classification rate of 99.8% ± 0.1 in the training set and 98.43% ± 1.79 in the validation set in AUC-ROC values. These findings have the potential to aid in the early detection and management of CKD, a complication of AKI resulting from COVID-19. Further research is required to confirm these results.

Dietary inflammatory index and lower glomerular filtration rate in Mexican adults

We hypothesized that higher scores on the dietary inflammatory index (DII) would be associated with a lower glomerular filtration rate (GFR). This cross-sectional study included 2098 participants from Mexican Teachers Cohort Study, the Health Workers Cohort Study, and the Comitán Study belonging to the RenMex consortium. Energy-adjusted DII scores were estimated using a semi-quantitative food frequency questionnaire (FFQ). eGFR was estimated by the CKD Epidemiology Collaboration equation. Quantile regression models and ordered regression models were estimated to assess the associations of interest. Median age of study participants was 47 years, median eGFR was 102.9 mL/min/1.73m2, and the median energy-adjusted DII was 0.89 (range, -2.25, +4.86). The median eGFR was lower in participants in the highest percentile of DII compared to those in the lowest percentile (103.8 vs 101.4). We found that continuous and categorical energy-adjusted DII scores were associated with lower eGFR, especially at the lower percentiles. In adjusted ordered logistic regression, we found that the highest DII category was associated with 1.80 times the odds of belonging to the mildly decreased eGFR category or moderately decreased eGFR category compared lowest DII category (OR: 1.80, 95%CI 1.35, 2.40). A high DII score was associated with a lower eGFR among the Mexican population. Additional studies are crucial to validate these findings and explore potential strategies to reduce the consumption of pro-inflammatory foods as a preventive approach for chronic kidney disease (CKD).

Intermittent protein restriction before but not after the onset of diabetic kidney disease attenuates disease progression in mice

Background

High dietary protein intake exacerbates proteinuria in individuals with diabetic kidney disease (DKD). However, studies on the impacts of low protein diet (LPD) on DKD have yielded conflicting results. Furthermore, patient compliance to continuous protein restriction is challenging.

Objective

The current study aims to investigate the effects of intermittent protein restriction (IPR) on disease progression of DKD.

Methods

Diabetic KK-Ay mice were used in this study. For the IPR treatment, three consecutive days of LPD were followed by four consecutive days of normal protein diet (NPD) within each week. For early intervention, mice received IPR before DKD onset. For late intervention, mice received IPR after DKD onset. In both experiments, age-matched mice fed continuous NPD served as the control group. Kidney morphology, structure and function of mice in different groups were examined.

Results

Intermittent protein restriction before DKD onset ameliorated pathological changes in kidney, including nephromegaly, glomerular hyperfiltration, tubular injuries and proteinuria, without improving glycemic control. Meanwhile, IPR initiated after DKD onset showed no renoprotective effects despite improved glucose homeostasis.

Conclusion

Intermittent protein restriction before rather than after DKD onset protects kidneys, and the impacts of IPR on the kidneys are independent of glycemic control. IPR shows promise as an effective strategy for managing DKD and improving patient compliance.

Metabolic MRI With Hyperpolarized 13 C-Pyruvate for Early Detection of Fibrogenic Kidney Metabolism

OBJECTIVES

Fibrosis is the final common pathway for chronic kidney disease and the best predictor for disease progression. Besides invasive biopsies, biomarkers for its detection are lacking. To address this, we used hyperpolarized 13 C-pyruvate MRI to detect the metabolic changes associated with fibrogenic activity of myofibroblasts.

MATERIALS AND METHODS

Hyperpolarized 13 C-pyruvate MRI was performed in 2 pig models of kidney fibrosis (unilateral ureteral obstruction and ischemia-reperfusion injury). The imaging data were correlated with histology, biochemical, and genetic measures of metabolism and fibrosis. The porcine experiments were supplemented with cell-line experiments to inform the origins of metabolic changes in fibrogenesis. Lastly, healthy and fibrotic human kidneys were analyzed for the metabolic alterations accessible with hyperpolarized 13 C-pyruvate MRI.

RESULTS

In the 2 large animal models of kidney fibrosis, metabolic imaging revealed alterations in amino acid metabolism and glycolysis. Conversion from hyperpolarized 13 C-pyruvate to 13 C-alanine decreased, whereas conversion to 13 C-lactate increased. These changes were shown to reflect profibrotic activity in cultured epithelial cells, macrophages, and fibroblasts, which are important precursors of myofibroblasts. Importantly, metabolic MRI using hyperpolarized 13 C-pyruvate was able to detect these changes earlier than fibrosis-sensitive structural imaging. Lastly, we found that the same metabolic profile is present in fibrotic tissue from human kidneys. This affirms the translational potential of metabolic MRI as an early indicator of fibrogenesis associated metabolism.

CONCLUSIONS

Our findings demonstrate the promise of hyperpolarized 13 C-pyruvate MRI for noninvasive detection of fibrosis development, which could enable earlier diagnosis and intervention for patients at risk of kidney fibrosis.