New Insights into Molecular Mechanisms of Chronic Kidney Disease

Advances in kidney disease: pathogenesis and therapeutic targets

Chronic kidney disease (CKD) is a global public health issue characterized by progressive loss of kidney function, of which end-stage kidney disease (ESKD) is the last stage. The global increase in the prevalence of CKD is linked to the increasing prevalence of traditional risk factors, including obesity, hypertension, and diabetes mellitus, as well as metabolic factors, particularly insulin resistance, dyslipidemia, and hyperuricemia. Mortality and comorbidities, such as cardiovascular complications, rise steadily as kidney function deteriorates. Patients who progress to ESKD require long-term kidney replacement therapy, such as transplantation or hemodialysis/peritoneal dialysis. It is currently understood that a crucial aspect of CKD involves persistent, low-grade inflammation. In addition, increased oxidative and metabolic stress, endothelial dysfunction, vascular calcification from poor calcium and phosphate metabolism, and difficulties with coagulation are some of the complex molecular pathways underlying CKD-related and ESKD-related issues. Novel mechanisms, such as microbiome dysbiosis and apolipoprotein L1 gene mutation, have improved our understanding of kidney disease mechanisms. High kidney disease risk of Africa has been linked to APOL1 high-risk alleles. The 3-fold increased risk of ESKD in African Americans compared to European Americans is currently mainly attributed to variants in the APOL1 gene in the chromosome 22q12 locus. Additionally, the role of new therapies such as SGLT2 inhibitors, mineralocorticoid receptor antagonists, and APOL1 channel function inhibitors offers new therapeutic targets in slowing down the progression of chronic kidney disease. This review describes recent molecular mechanisms underlying CKD and emerging therapeutic targets.

Psychiatric disorders and following risk of chronic kidney disease: a prospective cohort study from UK Biobank

BACKGROUND

Psychiatric disorders have been reported to influence many health outcomes, but evidence about their impact on chronic kidney disease (CKD) has not been fully explored, as well as possible mechanisms implicated are still unclear.

METHODS

Four hundred forty-one thousand eight hundred ninety-three participants from UK Biobank were included in this study. To assess the association between psychiatric disorders mainly including depression, anxiety, stress-related disorders, substance misuse as well as psychotic disorder, and CKD, a Cox regression model using age as the underlying time scale was employed. This approach considers the age progression of participants from the beginning to the end of the study as the elapsed time. Flexible nonparametric smoothing model was conducted to illustrate the temporal patterns. Subgroup analyses were performed by stratification of gender, genetic susceptibility to CKD, age at entry or exit the cohort, follow-up duration, and the number of psychiatric disorders at baseline. Mediation analysis was implemented to evaluate the roles of body mass index (BMI), hypertension, and diabetes.

RESULTS

Compared with individuals without psychiatric disorders, an increased risk of CKD was observed in patients with psychiatric disorders (hazard ratios (HR) = 1.52, 95% confidence intervals (CI): 1.40-1.65, p-value < 0.001). The hazard ratio among psychiatric patients gradually increased, and became significant after about 10 years follow-ups. The HR for patients followed up for 10-12 years was 1.60 (95% CI: 1.34-1.91, p-value < 0.001), and the HR was 1.66 (95% CI: 1.29-2.13, p-value < 0.001) for patients followed up for 12-13 years. Five distinct psychiatric disorders were found to be significantly associated with an increased risk of developing CKD. The highest HR was observed between stress-related disorder and CKD (HR = 1.95, 95%CI: 1.28-2.97, p-value = 0.002). When adjusting genetic susceptibility to CKD, the HR for the association between stress-related disorders and CKD became 1.86 (95%CI: 1.14-3.04, p-value = 0.013). Although these associations were nominally significant, they did not reach statistical significance after applying the Bonferroni multiple corrections, potentially due to the limited sample size. Subgroup analysis revealed that psychiatric patients who are under age 60, with multiple psychiatric morbidities or having been diagnosed with psychiatric disorders for over 10 years may be high-risk populations. Hypertension, BMI and diabetes mediated 49.13% (95% CI: 37.60%-67.08%), 12.11% (95% CI: 8.49%-17.24%) and 3.78% (95% CI: 1.58%-6.52%) of the total effect, respectively.

CONCLUSIONS

Psychiatric disorders were associated with a delayed onset of an elevated risk for CKD, this association was only observed in patients with psychiatric disorders for more than 10 years. Our study highlights the significance of lifestyle interventions, routine monitoring of kidney function, early screening for CKD, and personalized management strategies for psychiatric patients as potential approaches to the precise prevention of CKD.

Exploring the mechanism of Paotianxiong polysaccharide in the treatment of chronic kidney disease combining metabolomics and microbiomics technologies

A close relationship between the pathogenesis of chronic kidney disease (CKD) and abnormalities in the gut-kidney axis. Paotianxiong polysaccharides (PTXP) that have demonstrated therapeutic effects on CKD. However, the specific mechanism by which PTXP ameliorates CKD through the gut-kidney axis remains to be explored. In this study, the microbiomes and metabolomics were combined to investigate the impact of PTXP on intestinal flora structure and metabolism, further unveiling the relationship through correlation analysis. The results showed that PTXP intervention significantly modulated renal function abnormalities in CKD rats and significantly modulates gut microbial disorders, evidenced by an increased abundance of Lactobacillus murinus, Bacteroides fragilis, and a decreased abundance of Bifidobacterium pseudolongum. Furthermore, PTXP reversed the changes in intestinal metabolites, such as linoleic acid and docosahexaenoic acid, induced by CKD and identified unsaturated fatty acid metabolism as a key metabolic pathway. Correlation analyses also revealed associations among gut microorganisms, metabolites, and renal function indexes, confirming that PTXP alleviated CKD through the gut-kidney axis. Moreover, the above conclusions were verified by fecal bacteria transplantation experiments. These findings provide insights into the mechanism of PTXP for the treatment of CKD and provide new targets for the treatment of CKD.

The role of interleukin-20 and vascular endothelial growth factor-A biomarkers in the detection of renal impairment in patients with multiple myeloma

BACKGROUND

Multiple myeloma (MM) is a malignant incurable disease characterized by monoclonal plasma cell increase associated with renal impairment. Evaluation of neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), hemoglobin/red cell distribution width (HB/RDW), interleukin-20 (IL-20), and vascular endothelial growth factor-A (VEGFA) in patients with MM (with or without renal impairment) as prognostic and severity indicators.

RESEARCH DESIGN AND METHODS

A cross-sectional study was conducted on sixty MM patients with renal impairment, sixty MM patients without renal impairment, and sixty subjects (control group). Complete blood count, IL-20 immunoassay, and gene expression of IL-20, and VEGFA were evaluated.

RESULTS

Higher levels of NLR, MLR, and IL-20, and moreover lower levels of PLR, HB/RDW, as well as upregulation of IL-20, and VEGFA gene expression were detected in MM patients, especially those with renal impairment. Receiver operating characteristic curves analysis of NLR, MLR, PLR, and IL-20 showed high sensitivity and specificity in the diagnosis of MM and disease stages.

CONCLUSIONS

NLR, MLR, PLR, HB/RDW, IL-20, and VEGFA may be implicated in the inflammatory process of MM and renal impairment pathogenesis. NLR, MLR, and IL-20 can be used as prognostic markers in MM stages.

The association between patterns of exposure to adverse life events and the risk of chronic kidney disease: a prospective cohort study of 140,997 individuals

Exposure to adverse life events is linked to somatic disorders. The study aims to evaluate the association between adverse events at varying life stages and the risk of chronic kidney disease (CKD), a condition affecting about 10% population worldwide. This prospective cohort study included 140,997 participants from the UK Biobank. Using survey items related to childhood maltreatment, adulthood adversity and catastrophic trauma, we performed latent class analysis to summarize five distinct patterns of exposure to adverse life events, namely "low-level exposure", "childhood exposure", "adulthood exposure", "sexual abuse" and "child-to-adulthood exposure". We used Cox proportional hazard regression to evaluate the association of patterns of exposure to adverse life events with CKD, regression-based mediation analysis to decompose the total effect, and gene-environment-wide interaction study (GEWIS) to identify interactions between genetic loci and adverse life events. During a median follow-up of 5.98 years, 2734 cases of incident CKD were identified. Compared with the "low-level exposure" pattern, "child-to-adulthood exposure" was associated with increased risk of CKD (hazard ratio 1.37, 95% CI 1.14 to 1.65). BMI, smoking and hypertension mediated 11.45%, 9.79%, and 4.50% of this total effect, respectively. Other patterns did not show significant results. GEWIS and subsequent analyses indicated that the magnitude of the association between adverse life events and CKD differed according to genetic polymorphisms, and identified potential underlying pathways (e.g., interleukin 1 receptor activity). These findings underscore the importance of incorporating an individual's psychological encounters and genetic profiles into the precision prevention of CKD.

Absolute Stenosis Measures of Renal Artery Independently Influence Kidney Perfusion in Contrast-Enhanced Multidetector Computed Tomography

Background: A renal artery lumen reduction of ≥60% indicates hemodynamically significant stenosis and is one of the main criteria for invasive revascularization. We hypothesize that direct parameters describing renal artery stenosis (RAS) could better correlate with renal blood flow and improve the criterion for revascularization. This study aimed to investigate RAS parameters independently associated with renal blood flow estimated in contrast-enhanced multidetector computed tomography (CE-MDCT). Methods: Ultrasound Doppler dynamic renal cortical perfusion (dRCP), CE-MDCT with cortical blood flow (CBF), and RAS assessment in the form of cross-sectional area reduction (CSAR), maximal diameter reduction (MaxDR), mean diameter (MeD), and minimal diameter (MinD) were investigated. Results: CBF correlated with CSAR (r = -0.422, p = 0.003), MeD (r = 0.344, p = 0.005) and MinD (r = 0.348, p= 0.005), whereas RCP correlated only with MeD (r = 0.357, p = 0.005) and MinD (r = 0.427, p< 0.001). In multivariable regression, only MeD was independently associated with CBF (R2 = 0.179; p < 0.001), and MeD < 3.5 mm substantially indicated CBF < 175 mL/100 g/min in ROC analysis. Conclusions: The directly measured mean diameter of RAS is independently associated with renal cortex blood flow and is probably a more appropriate parameter for the invasive RAS treatment criterion.

The risk of solid organ tumors in patients with chronic kidney disease: A narrative review of literature

Chronic kidney disease (CKD) has been correlated with certain pathological conditions such as cardiovascular diseases and other renal-related dysfunctions. Some other reports suggested an association between CKD and the development of certain solid cancers. Therefore, we aimed to generate this narrative review to present the available literature on the risk of solid cancer development in CKD patient populations. We explored the associations between CKD, organ transplantation, and the development of specific solid organ tumors such as kidney, thyroid, lung, breast, bladder, gastric, and prostate cancers. In conclusion, the previous reports showed an increase in the risk of certain solid cancers such as kidney, lung, bladder, and possibly breast cancer in CKD patients and transplant recipients. On the other hand, thyroid, gastric, and prostate cancers showed unclear association with CKD. Despite the suggested impact of smoking and immunosuppression on the development of cancers in CKD patients, more studies are needed to elucidate the mechanism and the risk factors that might be related to the development of cancer in CKD patients.

Editorial for the Special Issue: Pathophysiology of Chronic Kidney Disease and Its Complications

Chronic kidney disease (CKD) is a risk factor for end-stage kidney disease, requiring renal replacement therapy [...].

Inspiring Tactics with the Improvement of Mitophagy and Redox Balance for the Development of Innovative Treatment against Polycystic Kidney Disease

Polycystic kidney disease (PKD) is the most common genetic form of chronic kidney disease (CKD), and it involves the development of multiple kidney cysts. Not enough medical breakthroughs have been made against PKD, a condition which features regional hypoxia and activation of the hypoxia-inducible factor (HIF) pathway. The following pathology of CKD can severely instigate kidney damage and/or renal failure. Significant evidence verifies an imperative role for mitophagy in normal kidney physiology and the pathology of CKD and/or PKD. Mitophagy serves as important component of mitochondrial quality control by removing impaired/dysfunctional mitochondria from the cell to warrant redox homeostasis and sustain cell viability. Interestingly, treatment with the peroxisome proliferator-activated receptor-α (PPAR-α) agonist could reduce the pathology of PDK and might improve the renal function of the disease via the modulation of mitophagy, as well as the condition of gut microbiome. Suitable modulation of mitophagy might be a favorable tactic for the prevention and/or treatment of kidney diseases such as PKD and CKD.

Administration of Bevacizumab and the Risk of Chronic Kidney Disease Development in Taiwan Residents: A Population-Based Retrospective Cohort Study

Vascular endothelial growth factor (VEGF) plays a significant role as a pro-angiogenic and pro-permeability factor within the kidney. Bevacizumab is a pharmaceutical monoclonal anti-VEGF antibody that inhibits the growth of new blood vessels, which blocks blood supply and thereby restricts tumor growth. Thus, we conducted a nationwide study to explore the risk of chronic kidney disease (CKD) development in Taiwan residents after bevacizumab therapy. We drew data from the extensive National Health Insurance Research Database (NHIRD), which encompasses data from >99% of Taiwan's population from 1995 onwards. Individuals who received bevacizumab between 2012-2018 were identified as the bevacizumab cohort, with the index date set at the first usage. We randomly selected dates within the study period for the control group to serve as index dates. We excluded patients with a history of CKD prior to the index date or those <20 years old. In both cohorts, patients' propensity scores matched in a 1:1 ratio based on sex, age, index year, income, urbanization level, comorbidities, and medications. We found patients treated with bevacizumab had a significantly higher risk of contracting CKD than patients without bevacizumab (adjusted hazard ratio = 1.35, 95% confidence interval = 1.35-1.73). The risk of CKD was 1.35-fold higher in participants with bevacizumab treatment than those in the control group. These findings suggest that close monitoring of CKD development after bevacizumab administration is needed.

Biomarkers of the End-Stage Renal Disease Progression: Beyond the GFR

Chronic kidney disease can progress to the end-stage renal disease (ESRD) characterized by a high risk of morbidity and mortality. ESRD requires immediate therapy or even dialysis or kidney transplantation, therefore, its timely diagnostics is critical for many patients. ESRD is associated with pathological changes, such as inflammation, fibrosis, endocrine disorders, and epigenetic changes in various cells, which could serve as ESRD markers. The review summarizes information on conventional and new ESRD biomarkers that can be assessed in kidney tissue, blood, and urine. Some biomarkers are specific to a particular pathology, while others are more universal. Here, we suggest several universal inflammatory, fibrotic, hormonal, and epigenetic markers indicative of severe deterioration of renal function and ESRD progression for improvement of ESRD diagnostics.