HDL abnormalities in nephrotic syndrome and chronic kidney disease

The association between monocyte to high-density lipoprotein cholesterol ratio and chronic kidney disease in a Chinese adult population: a cross-sectional study

BACKGROUND

Monocyte to high-density lipoprotein cholesterol ratio (MHR) was confirmed as a novel inflammatory marker and strongly associated with the risk of several diseases. This study aimed to investigate the relationship between MHR and chronic kidney disease (CKD) in a Chinese adult population.

METHODS

In this cross-sectional study, 232,775 community-dwelling adults in Binhai who completed health checkups in 2021 were enrolled. Participants were categorized based on the MHR quartiles. Clinical characteristics of participants across different groups were compared using one-way ANOVA, Kruskal-Wallis h-test, and Chi-squared test as appropriate. Univariate and multivariable logistic regression analyses were taken to assess the relationship between MHR and the presence of CKD, as well as its association with low estimated glomerular filtration rate (eGFR) and proteinuria. Subgroup analyses were further executed to confirm the reliability of this relationship.

RESULTS

A total of 21,014 (9.0%) individuals were diagnosed with CKD. Characteristic indicators including waist circumference, body mass index (BMI), blood pressure (BP), serum uric acid (SUA), triglyceride, and fasting blood glucose (FBG) showed a gradual increase with higher MHR quartiles, whereas parameters such as age, total cholesterol, high-density lipoprotein cholesterol (HDL-C), and eGFR decreased (p < .001). In the multivariable logistic regression analysis, we observed independent associations between MHR (per 1 SD increase) and CKD, as well as low eGFR and proteinuria, with odds ratio (ORs) and 95% confidence intervals (95%CIs) of 1.206 (1.186-1.225), 1.289 (1.260-1.319), and 1.150 (1.129-1.171), respectively (p < .001). Similar conclusions were confirmed in subgroup analysis stratified by gender, age, BMI, central obesity, hypertension, and diabetes mellitus, after justification for confounding factors.

CONCLUSION

Elevated MHR level was independently associated with the presence of CKD, suggesting that it might serve as a useful clinical tool for risk stratification, offering valuable insights to inform preventive and therapeutic approaches for clinicians in their routine medical practice.

Life's Essential 8 and heart failure among patients with chronic kidney disease: the Kailuan Cohort Study

AIMS

Patients with chronic kidney disease (CKD) are at an increased risk of developing heart failure. The American Heart Association recently released a new metric, Life's Essential 8 (LE8), for health promotion. However, evidence regarding associations between LE8 and heart failure risk among patients with CKD is scarce.

METHODS AND RESULTS

A total of 16 190 patients with CKD (mean age 55.9 years), free of cardiovascular disease at recruitment from the Kailuan Study, were included. Cardiovascular health was assessed using the LE8 score. Incident heart failure events were ascertained via linkage of electronic health record data. Cox proportional hazards regression models were used to compute hazard ratios (HRs) and 95% confidence intervals (CIs). There were 814 (5.0%) patients in the high LE8 criteria, with 13 180 (81.4%) in the moderate, and 2196 (13.6%) in the low LE8 category, respectively. During a median follow-up of 13.7 years, 724 incident heart failure cases were documented. Compared with the low LE8 category, the HRs (95% CIs) for heart failure were 0.58 (0.48, 0.71) for the moderate LE8 category and 0.32 (0.19, 0.54) for the high LE8 category (P for trend <0.001). In addition, the association was stronger in patients aged ≤65 years compared with their older counterparts (P for interaction = 0.01).

CONCLUSION

Our data showed a strong graded inverse association between the LE8-defined cardiovascular health and the risk of heart failure among patients with CKD. Our findings support the importance of adopting the LE8 among patients with CKD to prevent heart failure.

Multi-molecular hyperspectral PRM-SRS microscopy

Lipids play crucial roles in many biological processes. Mapping spatial distributions and examining the metabolic dynamics of different lipid subtypes in cells and tissues are critical to better understanding their roles in aging and diseases. Commonly used imaging methods (such as mass spectrometry-based, fluorescence labeling, conventional optical imaging) can disrupt the native environment of cells/tissues, have limited spatial or spectral resolution, or cannot distinguish different lipid subtypes. Here we present a hyperspectral imaging platform that integrates a Penalized Reference Matching algorithm with Stimulated Raman Scattering (PRM-SRS) microscopy. Using this platform, we visualize and identify high density lipoprotein particles in human kidney, a high cholesterol to phosphatidylethanolamine ratio inside granule cells of mouse hippocampus, and subcellular distributions of sphingosine and cardiolipin in human brain. Our PRM-SRS displays unique advantages of enhanced chemical specificity, subcellular resolution, and fast data processing in distinguishing lipid subtypes in different organs and species.

The causal effect of triglyceride and high blood pressure on IgA nephropathy: a Mendelian randomization study

Background

It has been reported that high blood pressure (HBP) and triglyceride (TG) are considered risk factors in immunoglobulin A nephropathy (IgAN). This study aimed to explore the causalities between HBP and TG, and IgAN on the basis of Mendelian randomization (MR) analysis.

Methods

Firstly, the genome-wide association study (GWAS) summary data of IgAN (GCST90018866) and two exposure factors, TG (ukb-d-30870_raw) and HBP (ukb-a-437), were sourced from the GWAS Catalog and Integrative Epidemiology Unit (IEU) OpenGWAS databases, respectively. In this study, five methods were utilized to perform MR analysis after picking out single nucleotide polymorphisms (SNPs) as instrumental variables, including MR-Egger, weighted median, simple mode, weighted mode, and inverse variance weighted (IVW), followed by the sensitivity analysis containing the heterogeneity, horizontal pleiotropy test and leave-one-out (LOO) analysis. Finally, the enrichment analysis and interaction network construction of genes corresponding to SNPs of HBP and TG were performed.

Results

The univariate MR results revealed that HBP and TG regarded as risk factors were causally related to IgAN [TG: p = 0.046, odds ratio (OR) = 1.065, 95% confidence interval (CI) = 1.001-1.133; HBP: p = 7.09 × 10-7, OR = 1.970, 95% CI = 1.507-2.575] based on random-effect IVM method, of which TG had a weaker impact. The reliability of these univariate MR results was certified by the sensitivity analysis, in which there was no horizontal pleiotropy and exaggerated influence of each SNP. Furthermore, HBP was markedly causally related to IgAN (p = 0.000512) with the help of multivariate MR analysis, rather than TG (p = 0.332). Therefore, when HBP and TG occur simultaneously, HBP is a direct influencing factor on IgAN. Ultimately, a total of 208 and 153 genes separately corresponding to SNPs of TG and HBP were included in enrichment analysis, and thereinto, genes relevant to TG were mainly enriched in lipid homeostasis and cholesterol metabolism, while genes concerned with HBP played their roles in regulation of cell growth, aldosterone synthesis and secretion and so forth.

Conclusion

TG and HBP as risk factors were causally connected with IgAN, of which HBP was strongly related to the onset of IgAN, providing more reliable evidence for further exploring the relationship between TG and HBP and IgAN.

Defining the threshold: triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio's non-linear impact on tubular atrophy in primary membranous nephropathy

Background

Hyperlipidemia is common in primary membranous nephropathy (PMN) patients, and tubular atrophy (TA) is an unfavorable prognostic factor. However, the correlation between the triglyceride to high-density lipoprotein cholesterol (TG/HDL-C) ratio and TA is controversial. Therefore, our study aimed to investigate the association between the TG/HDL-C ratio and TA in PMN patients.

Methods

We conducted a cross-sectional study and collected data from 363 PMN patients at Shenzhen Second People's Hospital from January 2008 to April 2023. The primary objective was to evaluate the independent correlation between the TG/HDL-C ratio and TA using binary logistic regression model. We used a generalized additive model along with smooth curve fitting and multiple sensitivity analyses to explore the relationship between these variables. Additionally, subgroup analyses were conducted to delve deeper into the results.

Results

Of the 363 PMN patients, 75 had TA (20.66%). The study population had a mean age of 46.598 ± 14.462 years, with 217 (59.78%) being male. After adjusting for sex, age, BMI, hypertension, history of diabetes, smoking, alcohol consumption, UPRO, eGFR, HB, FPG, and ALB, we found that the TG/HDL-C ratio was an independent risk factor for TA in PMN patients (OR=1.29, 95% CI: 1.04, 1.61, P=0.0213). A non-linear correlation was observed between the TG/HDL-C ratio and TA, with an inflection point at 4.25. The odds ratios (OR) on the left and right sides of this inflection point were 1.56 (95% CI: 1.17, 2.07) and 0.25 (95% CI: 0.04, 1.54), respectively. Sensitivity analysis confirmed these results. Subgroup analysis showed a consistent association between the TG/HDL-C ratio and TA, implying that factors such as gender, BMI, age, UPRO, ALB, hypertension and severe nephrotic syndrome had negligible effects on the link between the TG/HDL-C ratio and TA.

Conclusion

Our study demonstrates a non-linear positive correlation between the TG/HDL-C ratio and the risk of TA in PMN patients, independent of other factors. Specifically, the association is more pronounced when the ratio falls below 4.25. Based on our findings, it would be advisable to decrease the TG/HDL-C ratio below the inflection point in PMN patients as part of treatment strategies.

High-Density Lipoprotein Particles and Torque Teno Virus in Stable Outpatient Kidney Transplant Recipients

Torque teno virus (TTV) is emerging as a potential marker for monitoring immune status. In transplant recipients who are immunosuppressed, higher TTV DNA loads are observed than in healthy individuals. TTV load measurement may aid in optimizing immunosuppressive medication dosing in solid organ transplant recipients. Additionally, there is a growing interest in the role of HDL particles in immune function; therefore, assessment of both HDL concentrations and TTV load may be of interest in transplant recipients. The objective of this study was to analyze TTV loads and HDL parameters in serum samples collected at least one year post-transplantation from 656 stable outpatient kidney transplant recipients (KTRs), enrolled in the TransplantLines Food and Nutrition Cohort (Groningen, the Netherlands). Plasma HDL particles and subfractions were measured using nuclear magnetic resonance spectroscopy. Serum TTV load was measured using a quantitative real-time polymerase chain reaction. Associations between HDL parameters and TTV load were examined using univariable and multivariable linear regression. The median age was 54.6 [IQR: 44.6 to 63.1] years, 43.3% were female, the mean eGFR was 52.5 (±20.6) mL/min/1.73 m2 and the median allograft vintage was 5.4 [IQR: 2.0 to 12.0] years. A total of 539 participants (82.2%) had a detectable TTV load with a mean TTV load of 3.04 (±1.53) log10 copies/mL, the mean total HDL particle concentration was 19.7 (±3.4) μmol/L, and the mean HDL size was 9.1 (±0.5) nm. The univariable linear regression revealed a negative association between total HDL particle concentration and TTV load (st.β = -0.17, 95% CI st.β: -0.26 to -0.09, p < 0.001). An effect modification of smoking behavior influencing the association between HDL particle concentration and TTV load was observed (Pinteraction = 0.024). After adjustment for age, sex, alcohol intake, hemoglobin, eGFR, donor age, allograft vintage and the use of calcineurin inhibitors, the negative association between HDL particle concentration and TTV load remained statistically significant in the non-smoking population (st.β = -0.14, 95% CI st.β: -0.23 to -0.04, p = 0.006). Furthermore, an association between small HDL particle concentration and TTV load was found (st.β = -0.12, 95% CI st.β: -0.22 to -0.02, p = 0.017). Higher HDL particle concentrations were associated with a lower TTV load in kidney transplant recipients, potentially indicative of a higher immune function. Interventional studies are needed to provide causal evidence on the effects of HDL on the immune system.

Relation between interleukin-13 and annexin-V levels and carotid intima-media thickness in nephrotic syndrome

Background and aim

The aim of the current study is to assess the relation between carotid intima-media thickness (CIMT) measurements, renal Doppler resistive index (RI) and serum levels of interleukin-13 (IL-13) and annexin-V (An-V) in children with idiopathic nephrotic syndrome (INS).

Materials and methods

The present case-control study was conducted on 60 children with INS and 60 age- and sex-matched healthy children. All participants were subjected to evaluation of serum levels of IL-13 and An-V and ultrasound Doppler measurement of CIMT and renal RI.

Results

Patients expressed significantly higher An-V (5.9 ± 2.6 vs. 2.1 ± 0.8 ng/mL, p<0.001) and IL-13 (19.2 ± 7.6 vs. 3.4 ± 1.4 ng/L) levels when compared with healthy counterparts. Moreover, it was shown that patients had significantly higher CIMT (0.49 ± 0.06 vs. 0.35 ± 0.03, p<0.001) as compared to controls. No significant differences were noted between the studied groups regarding right or left RIs. Correlation analysis identified significant direct correlation between serum An-V levels and albumin/creatinine ratio (ACR) (r = 0.55), cholesterol (r = 0.48), triglycerides (r = 0.36), IL-13 (r = 0.92) and CIMT (r = 0.53). Similar correlations could be found between serum IL-13 levels and CIMT measurements and the corresponding parameters.

Conclusions

The present study suggests an association between higher early atherosclerosis expressed as elevated CIMT measurements in children with INS and elevated serum levels of An-V and IL-13.

Total Outflow of High-Density Lipoprotein-Cholesteryl Esters from Plasma Is Decreased in a Model of 3/4 Renal Mass Reduction

(1) Background: Previous studies have enriched high-density lipoproteins (HDL) using cholesteryl esters in rabbits with a three-quarter reduction in functional renal mass, suggesting that the kidneys participate in the cholesterol homeostasis of these lipoproteins. However, the possible role of the kidneys in lipoprotein metabolism is still controversial. To understand the role of the kidneys in regulating the HDL lipid content, we determined the turnover of HDL-cholesteryl esters in rabbits with a three-quarter renal mass reduction. (2) Methods: HDL subclass characterization was conducted, and the kinetics of plasma HDL-cholesteryl esters, labeled with tritium, were studied in rabbits with a 75% reduction in functional renal mass (Ntx). (3) Results: The reduced renal mass triggered the enrichment of cholesterol, specifically cholesteryl esters, in HDL subclasses. The exchange of cholesteryl esters between HDL and apo B-containing lipoproteins (VLDL/LDL) was not significantly modified in Ntx rabbits. Moreover, the cholesteryl esters of HDL and VLDL/LDL fluxes from the plasmatic compartment tended to decrease, but they only reached statistical significance when both fluxes were added to the Nxt group. Accordingly, the fractional catabolic rate (FCR) of the HDL-cholesteryl esters was lower in Ntx rabbits, concomitantly with its accumulation in HDL subclasses, probably because of the reduced mass of renal cells requiring this lipid from lipoproteins.

Technique failure in peritoneal dialysis-related peritonitis: risk factors and patient survival

OBJECTIVE

This study aimed to investigate the association between patient clinical characteristics and technique failure in peritoneal dialysis-related peritonitis (PDRP). The effect of peritonitis-associated technique failure on patient survival was also assessed.

METHODS

Patients diagnosed with PDRP from January 1, 2010 to June 30, 2022 were retrospectively reviewed and analyzed. Relevant demographic, biochemical, and clinical data were collected. Univariate and multivariate logistic regression analyses were used to determine the predictors of peritonitis-associated technique failure in PD. Patients were divided into technique failure (F group) and nontechnique failure (NF group) groups. Patients were followed until death or until the date of Oct 1, 2022. Kaplan-Meier survival curves and landmark analysis were used to assess the survival of the PDRP cohort. Cox regression models were used to assess the association between potential risk factors and mortality.

RESULTS

A total of 376 patients with 648 cases of PDRP were included in this study. Multivariate logistic regression analysis demonstrated that peritoneal dialysis (PD) duration (OR = 1.12 [1.03, 1.21], p = 0.005), dialysate WBC count on Day 3 after antibiotic therapy (OR = 1.41 [1.22, 1.64], p = 0.001), blood neutrophil-to-lymphocyte ratio (NLR) (OR = 1.83 [1.25, 2.70], p = 0.002), and serum lactate dehydrogenase (LDH) (OR = 4.13 [1.69, 10.11], p = 0.002) were independent predictors for technique failure in PDRP. Furthermore, serum high-density lipoprotein (HDL) (OR = 0.28 [0.13, 0.64], p = 0.002) was a protective factor against technique failure. According to the Kaplan-Meier analysis, patients experiencing peritonitis-associated technique failure had lower postperitonitis survival (log-rank = 4.326, p = 0.038). According to the landmark analysis, patients with a history of peritonitis-associated technical failures had a higher 8-year mortality after peritoneal dialysis. A Cox model adjusted for plausible predetermined confounders showed that technique failure was independently associated with all-cause mortality.

CONCLUSIONS

Dialysate WBC count on Day 3, PD duration, NLR, and LDH were independent risk factors for technique failure, whereas HDL was a protective factor. Peritonitis-associated technique failure had a higher risk of mortality and adverse effects on postperitonitis survival.

Delayed diagnosis and exacerbation of hyperlipidemia in idiopathic nephrotic syndrome in children during the COVID-19 pandemic

BACKGROUND

During the coronavirus disease-2019 (COVID-19) pandemic, there was a lack of access to outpatient facilities for other diseases. Conversely, few studies have reported changes in clinical features of idiopathic nephrotic syndrome (INS) in children before and after the COVID-19 pandemic.

METHODS

Thirty-two children with primary INS, who were admitted to four Showa University-affiliated hospitals between January 2017 and December 2022, were enrolled in this retrospective study. Children were divided according to the onset of INS into a post-COVID-19 group (onset in 2020-2022, n = 25) and a pre-COVID-19 group (onset in 2017-2019, n = 32). We compared the clinical characteristics and features of initial INS between two groups.

RESULTS

In the post-COVID-19 group, these patients had interval between noticing symptoms of INS, such as edema and INS diagnosis was significantly longer (7 days versus 3.5 days; p = 0.0047), and had significantly raised serum LDL cholesterol levels at the time of INS diagnosis than in the pre-COVID-19 group (314 mg/dL versus 260 mg/dL; p = 0.028). Likewise, steroid-resistant nephrotic syndrome was significantly more common in the post-COVID-19 group [32% (n = 8) versus 6% (n = 2); p = 0.016]. A correlation analysis revealed a moderate positive correlation between the interval from symptom to diagnosis and LDL cholesterol (r = 0.460015, p = 0.0003).

CONCLUSIONS

Children with INS after the COVID-19 pandemic showed a longer time between noticing symptoms of INS and diagnosis, increased serum LDL cholesterol and more steroid resistance than before the pandemic.

High-sulfated derivative of polysaccharide from Ulva pertusa improves Adriamycin-induced nephrotic syndrome by suppressing oxidative stress

Nephrotic syndrome (NS) is characterized by proteinuria, hyperlipidemia, and hypoalbuminemia. Ulva pertusa, a green seaweed, is a nutritional supplement. In this study, the high-sulfated derivative of Ulva pertusa polysaccharide (HU) was prepared by combining U pertusa polysaccharide with chlorosulfonic acid. The NS rat model was established by tail vein single injection of Adriamycin (6.0 mg kg-1). Normal rats were used as the control group. NS rat models were treated with HU or U (173 mg kg-1 day-1). After treatment for 6 weeks, we assessed urine protein, renal function, and blood lipids, and observed morphology and histologic injury of the kidney and glomerular microstructure. Furthermore, we detected antioxidant enzyme activity and expression level of the Keap1/Nrf2 signaling pathway to explore the potential mechanism of HU. Results showed that HU not only alleviated hyperlipidemia and hypoalbuminemia, but also reduced urine protein by inhibiting podocyte detachment, thickening of the glomerular basement membrane, and expression of kidney fibrosis markers (collagens I and IV). In addition, HU enhanced antioxidant enzyme activity (GSH-Px, CAT, SOD) in both serum and the kidney, which may be due to upregulating the expression of Nrf2 and downregulating the expression of Keap1. In conclusion, HU appears to be effective in attenuating NS in rats through suppressing oxidative stress by regulating the Keap1/Nrf2 signaling pathway.

Bibliometric visualization analysis of gut-kidney axis from 2003 to 2022

Background: The gut-kidney axis refers to the interaction between the gastrointestinal tract and the kidneys, and its disorders have become increasingly important in the development of kidney diseases. The aim of this study is to identify current research hotspots in the field of the gut-kidney axis from 2003 to 2022 and provide guidance for future research in this field. Methods: We collected relevant literature on the gut-kidney axis from the Web of Science Core Collection (WoSCC) database and conducted bibliometric and visualization analyses using biblioshiny in R-Studio and VOSviewer (version 1.6.16). Results: A total of 3,900 documents were retrieved from the WoSCC database. The publications have shown rapid expansion since 2011, with the greatest research hotspot emerging due to the concept of the "intestinal-renal syndrome," first proposed by Meijers. The most relevant journals were in the field of diet and metabolism, such as Nutrients. The United States and China were the most influential countries, and the most active institute was the University of California San Diego. Author analysis revealed that Denise Mafra, Nosratola D. Vaziri, Fouque, and Denis made great contributions in different aspects of the field. Clustering analysis of the keywords found that important research priorities were "immunity," "inflammation," "metabolism," and "urinary toxin," reflecting the basis of research in the field. Current research frontiers in the field include "hyperuricemia," "gut microbiota," "diabetes," "trimethylamine n-oxide," "iga nephropathy," "acute kidney injury," "chronic kidney disease," "inflammation," all of which necessitate further investigation. Conclusion: This study presents a comprehensive bibliometric analysis and offers an up-to-date outlook on the research related to the gut-kidney axis, with a specific emphasis on the present state of intercommunication between gut microbiota and kidney diseases in this field. This perspective may assist researchers in selecting appropriate journals and partners, and help to gain a deeper understanding of the field's hotspots and frontiers, thereby promoting future research.

Intestinal Lymphatic Dysfunction in Kidney Disease

Kidney disease is associated with adverse consequences in many organs beyond the kidney, including the heart, lungs, brain, and intestines. The kidney-intestinal cross talk involves intestinal epithelial damage, dysbiosis, and generation of uremic toxins. Recent studies reveal that kidney injury expands the intestinal lymphatics, increases lymphatic flow, and alters the composition of mesenteric lymph. The intestinal lymphatics, like blood vessels, are a route for transporting potentially harmful substances generated by the intestines. The lymphatic architecture and actions are uniquely suited to take up and transport large macromolecules, functions that differentiate them from blood vessels, allowing them to play a distinct role in a variety of physiological and pathological processes. Here, we focus on the mechanisms by which kidney diseases result in deleterious changes in intestinal lymphatics and consider a novel paradigm of a vicious cycle of detrimental organ cross talk. This concept involves kidney injury-induced modulation of intestinal lymphatics that promotes production and distribution of harmful factors, which in turn contributes to disease progression in distant organ systems.

The causal effects of lipid traits on kidney function in Africans: bidirectional and multivariable Mendelian-randomization study

BACKGROUND

Observational studies have investigated the effect of serum lipids on kidney function, but these findings are limited by confounding, reverse causation and have reported conflicting results. Mendelian randomization (MR) studies address this confounding problem. However, they have been conducted mostly in European ancestry individuals. We, therefore, set out to investigate the effect of lipid traits on the estimated glomerular filtration rate (eGFR) based on serum creatinine in individuals of African ancestry.

METHODS

We used the two-sample and multivariable Mendelian randomization (MVMR) approaches; in which instrument variables (IV's) for the predictor (lipid traits) were derived from summary-level data of a meta-analyzed African lipid GWAS (MALG, n = 24,215) from the African Partnership for Chronic Disease Research (APCDR) (n = 13,612) & the Africa Wits-IN-DEPTH partnership for Genomics studies (AWI-Gen) dataset (n = 10,603). The outcome IV's were computed from the eGFR summary-level data of African-ancestry individuals within the Million Veteran Program (n = 57,336). A random-effects inverse variance method was used in our primary analysis, and pleiotropy was adjusted for using robust and penalized sensitivity testing. The lipid predictors for the MVMR were high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides (TG).

FINDINGS

We found a significant causal association between genetically predicted low-density lipoprotein (LDL) cholesterol and eGFR in African ancestry individuals β = 1.1 (95% CI [0.411-1.788]; p = 0.002). Similarly, total cholesterol (TC) showed a significant causal effect on eGFR β = 1.619 (95% CI [0.412-2.826]; p = 0.009). However, the IVW estimate showed that genetically predicted HDL-C β = -0.164, (95% CI = [-1.329 to 1.00]; p = 0.782), and TG β = -0.934 (CI = [-2.815 to 0.947]; p = 0.33) were not significantly causally associated with the risk of eGFR. In the multivariable analysis inverse-variance weighted (MVIVW) method, there was evidence for a causal association between LDL and eGFR β = 1.228 (CI = [0.477-1.979]; p = 0.001). A significant causal effect of Triglycerides (TG) on eGFR in the MVIVW analysis β = -1.3 ([-2.533 to -0.067]; p = 0.039) was observed as well. All the causal estimates reported reflect a unit change in the outcome per a 1 SD increase in the exposure. HDL showed no evidence of a significant causal association with eGFR in the MVIVW method (β = -0.117 (95% CI [-1.252 to 0.018]; p = 0.840)). We found no evidence of a reverse causal impact of eGFR on serum lipids. All our sensitivity analyses indicated no strong evidence of pleiotropy or heterogeneity between our instrumental variables for both the forward and reverse MR analysis.

INTERPRETATION

In this African ancestry population, genetically predicted higher LDL-C and TC are causally associated with higher eGFR levels, which may suggest that the relationship between LDL, TC and kidney function may be U-shaped. And as such, lowering LDL_C does not necessarily improve risk of kidney disease. This may also imply the reason why LDL_C is seen to be a poorer predictor of kidney function compared to HDL. In addition, this further supports that more work is warranted to confirm the potential association between lipid traits and risk of kidney disease in individuals of African Ancestry.

FUNDING

Wellcome (220740/Z/20/Z).

Data-driven subgroups of prediabetes and the associations with outcomes in Chinese adults

Prediabetes and its pathophysiology remain important issues. We aimed to examine the cluster characteristics of prediabetes and explore their associations with developing diabetes and its complications based on 12 variables representing body fat, glycemic measures, pancreatic β cell function, insulin resistance, blood lipids, and liver enzymes. A total of 55,777 individuals with prediabetes from the China Cardiometabolic Disease and Cancer Cohort (4C) were classified at baseline into six clusters. During a median of 3.1 years of follow-up, significant differences in the risks of diabetes and its complications between clusters were observed. The odds ratios of diabetes stepwisely increase from cluster 1 to cluster 6. Clusters 1, 4, and 6 have increased chronic kidney diseases risks, while the prediabetes in cluster 4, characterized by obesity and insulin resistance, confers higher risks of cardiovascular diseases compared with others. This subcategorization has potential value in developing more precise strategies for targeted prediabetes prevention and treatment.

Long-term visit-to-visit variability in low-density lipoprotein cholesterol is associated with poor cardiovascular and kidney outcomes in patients with primary nephrotic syndrome

PURPOSE

It is unclear whether long-term variability in low-density lipoprotein cholesterol (LDL-C) is associated with clinical outcomes in patients with nephrotic syndrome (NS).

METHODS

A large cohort of 1100 patients with primary NS underwent treatment and regular follow-up. Long-term variability in LDL-C was assessed by calculating its weighted standard deviation (w-SD). The primary endpoints of this study were the occurrence of arteriosclerotic cardiovascular disease (ASCVD) or kidney dysfunction. Factors associated with the w-SD of LDL-C were evaluated by linear regression. Associations of the w-SD of LDL-C with clinical outcomes were evaluated by Cox proportional hazards regression.

RESULTS

Over a median follow-up of 44.8 (interquartile range, 26.8, 70.1) months, 198 patients developed ASCVD (45.9 cases per 1,000 patient-years), and 84 patients developed kidney dysfunction (17.6 cases per 1,000 patient-years). The incidence rates of the primary outcomes increased across the quartiles of the w-SD of LDL-C (log-rank, P < 0.001). Multivariate Cox regression analysis showed that higher LDL-C variability was associated with an increased risk of ASCVD [hazard ratio (HR), 2.236; 95% confidence interval (CI), 1.684-2.969, P < 0.001] and an increased risk of kidney dysfunction (HR, 3.047; 95% CI 2.240-4.144, P < 0.001). The results were similar after adjusting the w-SD of LDL-C by its related parameters (baseline and mean LDL-C as well as mean total cholesterol), although the mean LDL-C was also an independent risk factor for ASCVD and kidney dysfunction.

CONCLUSION

Long-term variability in LDL-C was independently associated with the risk of ASCVD and kidney dysfunction in NS patients.

Effect of high density lipoprotein cholesterol (HDL-C) on renal outcome in patients with nephrotic syndrome complicated with steroid-induced diabetes mellitus(SIDM)

OBJECTIVE

We aimed to investigate the renal prognosis of patients with idiopathic nephrotic syndrome (INS) complicated with steroid-induced diabetes mellitus (SIDM), the association of high-density lipoprotein cholesterol (HDL-C) before glucocorticoid treatment with renal prognosis, and the risk for persistent diabetes among patients with INS who had withdrawn from steroid therapy.

MATERIALS AND METHODS

We retrospectively analyzed 239 patients with INS complicated with SIDM at the National Clinical Research Center of Kidney Diseases, Jinling Hospital, from January 2008 to December 2019. The primary endpoint was the composite renal outcome defined as the development of end-stage renal disease (ESRD) or a 50% decrease in estimated glomerular filtration rate (eGFR) for more than 24 months after glucocorticoid withdrawal. The secondary endpoint was persistent diabetes, defined as fulfilling the criteria for diagnosing diabetes or using antidiabetic medications for at least 24 months after glucocorticoid withdrawal.

RESULTS

After glucocorticoid withdrawal for over 24 months, 35 (14.6%) patients reached the composite renal endpoint: end-stage renal disease (n = 14) or a 50% decrease in eGFR (n = 21). Before glucocorticoid therapy, a level of HDL-C greater than 1.45 mmol/L worsened renal survival in patients with INS complicated with SIDM. The log₁₀ the level of HDL-C before glucocorticoid treatment was an independent risk factor for the renal outcome. A prediction model was generated: Hazard ratio (renal outcome) = 0.94 * hypertension before glucocorticoid therapy + 2.29 * log₁₀ level of HDL-C before glucocorticoid treatment + 0.90 * the grade of interstitial tubule injury (AUROC, 0.75; 95% CI, 0.63 to 0.87; P < 0.01). Meanwhile, a level of fasting plasma glucose (FPG) before glucocorticoid treatment greater than 5.2 mmol/L enhanced the likelihood of persistent diabetes for at least 24 months after glucocorticoid withdrawal.

CONCLUSIONS

Increased level of HDL-C before glucocorticoid therapy was independently associated with a higher risk for renal outcome and thus may be useful in the renal prognosis of patients with INS complicated with SIDM.

A rare case of nephrotic syndrome and Tangier disease

Rarely, disorders of lipid metabolism cause nephrotic syndrome with progressive kidney disease. Tangier disease is a rare condition belonging to this family of lipid disorders; however, it is not associated with kidney disease. We report a patient presenting with nephrotic syndrome, leading to the unmasking of Tangier disease. A 34-year-old man presented with ankle oedema, nephrotic-range proteinuria and hypoalbuminaemia. Kidney biopsy demonstrated membranous nephropathy with features of immunoperoxidase staining, suggesting a secondary aetiology. Acute serology was negative. Imaging showed lymphadenopathy with splenomegaly suggestive of lymphoproliferative disorder. Bone marrow biopsy revealed foamy macrophages with widespread lipid deposition. Genomic sequencing revealed a pathological homozygous variant for ATP-binding cassette subfamily A member 1 (ABCA1) c.1510-1G > A, consistent with Tangier disease. Review of the ultrastructural kidney biopsy features demonstrated, in addition to membranous subepithelial and intramembranous usual-type electron-dense deposits, intramembranous osmiophilic lipid deposits similar to those in LCAT deficiency. The patient's renal function gradually declined (serum creatinine 133 µmol/L); therefore, he was started on rituximab. Metabolic disorders causing nephrotic syndrome are rare and even more so their association with membranous nephropathy. These should be considered in cases with unexplained persistent nephrotic syndrome with progressive kidney disease and lipid deposits on renal biopsy.

Dicarbonyl-modified lipoproteins contribute to proteinuric kidney injury

Lipoprotein modification by reactive dicarbonyls, including isolevuglandin (IsoLG), produces dysfunctional particles. Kidneys participate in lipoprotein metabolism, including tubular uptake. However, the process beyond the proximal tubule is unclear, as is the effect of kidney injury on this pathway. We found that patients and animals with proteinuric injury have increased urinary apolipoprotein AI (apoAI), IsoLG, and IsoLG adduct enrichment of the urinary apoAI fraction compared with other proteins. Proteinuric mice, induced by podocyte-specific injury, showed more tubular absorption of IsoLG-apoAI and increased expression of lipoprotein transporters in proximal tubular cells compared with uninjured animals. Renal lymph reflects composition of the interstitial compartment and showed increased apoAI and IsoLG in proteinuric animals, supporting a tubular cell-interstitium-lymph pathway for renal handling of lipoproteins. IsoLG-modified apoAI was not only a marker of renal injury but also directly damaged renal cells. IsoLG-apoAI increased inflammatory cytokines in cultured tubular epithelial cells (TECs), activated lymphatic endothelial cells (LECs), and caused greater contractility of renal lymphatic vessels than unmodified apoAI. In vivo, inhibition of IsoLG by a dicarbonyl scavenger reduced both albuminuria and urinary apoAI and decreased TEC and LEC injury, lymphangiogenesis, and interstitial fibrosis. Our results indicate that IsoLG-modified apoAI is, to our knowledge, a novel pathogenic mediator and therapeutic target in kidney disease.

Kidney and lipids: novel potential therapeutic targets for dyslipidemia in kidney disease?

INTRODUCTION

Altered lipid distribution and metabolism may lead to the development and/or progression of chronic kidney disease (CKD). Dyslipidemia is a major risk factor for CKD and increases the risk of cardiovascular events and mortality. Therefore, lipid-lowering treatments may decrease cardiovascular risk and prevent death.

AREAS COVERED

Key players involved in regulating lipid accumulation in the kidney; contribution of lipids to CKD progression, lipotoxicity, and mitochondrial dysfunction in kidney disease; recent therapeutic approaches for dyslipidemia.

EXPERT OPINION

The precise mechanisms for regulating lipid metabolism, particularly in kidney disease, are poorly understood. Guidelines for lipid-lowering therapy for CKD are controversial. Several hypolipemic therapies are available, but compared to others, statin therapy is the most common. No clinical trial has evaluated the efficacy of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) in preventing cardiovascular events or improving kidney function among patients with CKD or kidney transplant recipients. Attractive alternatives, such as PCSK9-small interfering RNA (siRNA) molecules or evinacumab are available. Additionally, several promising agents, such as cyclodextrins and the FXR/TGR5 dual agonist, INT-767, can improve renal lipid metabolism disorders and delay CKD progression. Drugs targeting mitochondrial dysfunction could be an option for the treatment of dyslipidemia and lipotoxicity, particularly in renal diseases.

Non-High-Density Lipoprotein Cholesterol and Cardiovascular Outcomes in Chronic Kidney Disease: Results from KNOW-CKD Study

As non-high-density lipoprotein cholesterol (non-HDL-C) levels account for all atherogenic lipoproteins, serum non-HDL-C level has been suggested to be a marker for cardiovascular (CV) risk stratification. Therefore, to unveil the association of serum non-HDL-C levels with CV outcomes in patients with non-dialysis chronic kidney disease (ND-CKD), the patients at stages 1 to 5 (n = 2152) from the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD) were prospectively analyzed. The subjects were divided into quintiles by serum non-HDL-C level. The primary outcome was a composite of all-cause death or non-fatal CV events. The median duration of follow-up was 6.940 years. The analysis using the Cox proportional hazard model unveiled that the composite CV event was significantly increased in the 5th quintile (adjusted hazard ratio 2.162, 95% confidence interval 1.174 to 3.981), compared to that of the 3rd quintile. A fully adjusted cubic spline model depicted a non-linear, J-shaped association between non-HDL-C and the risk of a composite CV event. The association remained robust in a series of sensitivity analyses, including the analysis of a cause-specific hazard model. Subgroup analyses reveled that the association is not significantly altered by clinical conditions, including age, gender, body mass index, estimated glomerular filtration rate, and albuminuria. In conclusion, high serum non-HDL-C level increased the risk of adverse CV outcomes among the patients with ND-CKD. Further studies are warranted to define the optimal target range of non-HDL-C levels in this population.

Triglycerides as Biomarker for Predicting Systemic Lupus Erythematosus Related Kidney Injury of Negative Proteinuria

Fewer biomarkers can be used to predict systemic lupus erythematosus (SLE) related kidney injury. This paper presents an apriori algorithm of association rules to mine the predictive biomarkers for SLE-related kidney injury of negative proteinuria. An apriori algorithm of association rules was employed to identify biomarkers, and logistic regression analysis and spearman correlation analysis were used to evaluate the correlation between triglycerides and SLE-related kidney injury of negative proteinuria. Triglycerides were mined out by the apriori algorithm of association rules. The level of triglycerides was significantly higher, and it was an independent risk factor for SLE-related kidney injury. In the high-triglycerides group, the number of patients with SLE-related kidney injury, SLEDAI-2K, urine P-CAST, the level of blood urea nitrogen, serum creatinine, and proteinuria were increased. Triglycerides level was positively correlated with proteinuria and P-CAST and negatively correlated with albumin and IgG. The area under the ROC curve of triglycerides and triglycerides combined proteinuria was 0.72 and 0.82, respectively. Significantly, 50% of SLE-related kidney injuries of negative proteinuria could be identified by high triglycerides levels. High triglycerides level was found at the time of onset of kidney injury, and it was opposite to glomerular filtration rate. Triglycerides may be a potential marker for predicting SLE-related kidney injury, especially in SLE-related kidney injury of negative proteinuria. Triglycerides combined proteinuria could predict SLE-related kidney injury effectively.

Prognostic Value of Triglyceride to High-Density Lipoprotein Cholesterol Ratio (TG/HDL-C) in IgA Nephropathy Patients

Background

The triglycerides to high-density lipoprotein cholesterol (TG/HDL-C) ratio is an easy-to-use atherogenic and prognostic marker which has attracted increasing attention these days. However, whether TG/HDL-C correlate with outcomes in IgA nephropathy (IgAN) patients remains unknown. To clarify these issues, we conducted this study.

Methods

A total of 1146 patients from West China Hospital of Sichuan University were retrospectively analysed between 2008 and 2018.The demographic, clinical and pathological data of all patients at the time of biopsy were collected. Then, patients were divided into the high TG/HDL group (TG/HDL ≥ 1.495, N=382) and the low TG/HDL group (TG/HDL-C < 1.495, N=764) based on the optimal cut-off value of the TG/HDL-C using receive operating curve. Cox proportional hazard models and Kaplan-Meier curves were used to evaluate the renal outcomes of IgAN.

Results

The median age of the patients was 33 (26-42) years, and 44.5% were men. By correlation analysis, we found that the TG/HDL-C ratio was negatively correlated with the eGFR (r = 0.250, P < 0.001) but positively correlated with proteinuria (r = 0.230, P< 0.001), BMI (r=0.380, P<0.001) and serum uric (r =0.308, P< 0.001). Patients with a higher TG/HDL-C ratio tended to have hypertension [odds ratio (OR), 1.987; 95% CI, 1.527-2.587; P<0.001] and more severe pathologic lesions with tubular atrophy/interstitial fibrosis (OR, 1.610; 95% CI, 1.203-2.154; P=0.001). During a median follow-up period of 54.1 (35.6-73.2) months, a high TG/HDL ratio was strongly associated with worse renal survival in IgAN patients (log-rank: P <0.001). Multivariate Cox analysis demonstrated that a high TG/HDL-C ratio (HR 1.775, 95% CI 1.056-2.798; P=0.029) was an independent predictive marker to ESRD.

Conclusion

In this study, we addressed the importance of TG/HDL-C ratio as a predictive marker for IgAN progression.

Signaling pathways of chronic kidney diseases, implications for therapeutics

Chronic kidney disease (CKD) is a chronic renal dysfunction syndrome that is characterized by nephron loss, inflammation, myofibroblasts activation, and extracellular matrix (ECM) deposition. Lipotoxicity and oxidative stress are the driving force for the loss of nephron including tubules, glomerulus, and endothelium. NLRP3 inflammasome signaling, MAPK signaling, PI3K/Akt signaling, and RAAS signaling involves in lipotoxicity. The upregulated Nox expression and the decreased Nrf2 expression result in oxidative stress directly. The injured renal resident cells release proinflammatory cytokines and chemokines to recruit immune cells such as macrophages from bone marrow. NF-κB signaling, NLRP3 inflammasome signaling, JAK-STAT signaling, Toll-like receptor signaling, and cGAS-STING signaling are major signaling pathways that mediate inflammation in inflammatory cells including immune cells and injured renal resident cells. The inflammatory cells produce and secret a great number of profibrotic cytokines such as TGF-β1, Wnt ligands, and angiotensin II. TGF-β signaling, Wnt signaling, RAAS signaling, and Notch signaling evoke the activation of myofibroblasts and promote the generation of ECM. The potential therapies targeted to these signaling pathways are also introduced here. In this review, we update the key signaling pathways of lipotoxicity, oxidative stress, inflammation, and myofibroblasts activation in kidneys with chronic injury, and the targeted drugs based on the latest studies. Unifying these pathways and the targeted therapies will be instrumental to advance further basic and clinical investigation in CKD.

HDL and Kidney Diseases

Serum lipid profiles, as well as HDL can be altered in patients with kidney diseases. There are various types of kidney diseases, including nephrotic syndrome and chronic kidney disease. In patients with nephrotic syndrome, plasma levels of HDL cholesterol and ApoA-I were within or below the normal limits. The HDL cholesterol: total cholesterol ratio decreased compared to healthy individuals. In patients with chronic kidney disease (CKD), reverse cholesterol transport function of HDL is impaired, and CKD also affects the composition and function of HDL. Cardiovascular disease (CVD) is the severe complication of CKD. Furthermore, HDL might also be a potential target for the prevention of cardiovascular complications associated with CKD.

Neutrophil to high-density lipoprotein ratio associates with higher all-cause mortality and new onset cardiovascular events in peritoneal dialysis patients

BACKGROUND

Neutrophil to high-density lipoprotein ratio (NHR), a new inflammatory marker, is associated with poor clinical prognosis. However, the correlation of NHR and adverse outcomes in peritoneal dialysis (PD) patients remains unclear.

METHODS

In this retrospective cohort study, a total of 1051 PD patients were recruited from three centers during Jan 1, 2009 to Dec 31, 2017. Eligible patients were distributed according to quartiles of the NHR. Kaplan-Meier cumulative incidence curves, multivariate COX regression, competitive risk analysis and restricted cubic spline (RCS) were applied to analyze the relationship between NHR and all-cause mortality as well as cardiovascular events (CVE). In addition, forest plots were used to calculate the interaction between different subgroups.

RESULTS

During follow-up, a total of 240 all-cause mortality and 157 new-onset CVE were recorded. The all-cause mortality in the highest quartile of NHR (> 5.43) were higher than those in the other groups. RCS showed a non-linear relationship between NHR and adverse outcomes. Multivariate COX regression indicated elevated NHR was an independent risk factor for all-cause mortality. Compared to the highest quartile, hazard ratio (HR) of new-onset CVE equals to 0.522 (95% CI 0.321-0.849) in the secondary quartile (2.43 < NHR ≤ 3.57), and the HR of all-cause mortality analysis is 0.551 (95% CI 0.378-0.803) in the third quartile (3.57 < NHR ≤ 5.43). Kaplan-Meier analysis suggested there were significant differences in all-cause mortality and new-onset CVE among four NHR groups.

CONCLUSIONS

NHR was a new independent risk factor for all-cause mortality in PD patients.

Association between lipid profile and residual renal function in incident peritoneal dialysis patients

INTRODUCTION

Residual renal function (RRF) is one of the most crucial factor in the management of peritoneal dialysis (PD). The aim of this study was to evaluate the association between lipid profile and preservation of RRF among incident PD patients.

METHODS

This retrospective cohort study investigated 113 patients (male, 72%; age, 59±14 years) who initiated PD between 2006 and 2017. We investigated the relationships between high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) at PD initiation and change in renal Kt/V during the first year after PD initiation.

RESULTS

Alterations in renal Kt/V during the first year after PD initiation correlated negatively with HDL-C at PD initiation, but not with LDL-C. On multivariate analysis, HDL-C at PD initiation was independently associated with change in renal Kt/V during the first year after PD initiation.

CONCLUSION

These results suggests importance of lipid management among incident PD patients for preservation of RRF.

Prognostic value of metabolic syndrome in renal structural changes in type 2 diabetes

PURPOSE

To investigate the prognostic value of metabolic syndrome (MetS) and its relationship with renal structure changes in patients with type 2 diabetes and associated diabetic nephropathy (DN).

METHODS

411 Chinese patients with type 2 diabetes and biopsy-confirmed DN were enrolled in this retrospective study. MetS was defined according to the modified criteria of the 2005 International Diabetes Federation. Baseline demographics and clinical information at the time of renal biopsy were extracted from the hospital's electronic medical records system. Renal pathological findings were assessed according to Renal Pathology Society system. Univariate and multivariate logistic regression analyses were performed to define the pathological covariates associated with MetS. A competing risk model, with death as the competing risk, was used to estimate the sub-distribution hazard ratio (SHR) of MetS for end-stage kidney disease (ESKD).

RESULTS

224 (55%) patients had MetS. Patients with MetS had poor renal function and more severe interstitial fibrosis tubular atrophy scores (IFTA) than those without MetS. Multivariate logistic regression analysis revealed that IFTA was significantly associated with MetS (odds ratio per score increase 1.45, 95% confidence interval [CI] 1.02-2.05). Of the patients with DN at risk, 40% of patients progressed to ESKD. After adjusting for renal function and pathological parameters, the presence of MetS was an independent predictor for progression to ESKD (SHR 1.93, 95% CI 1.34-2.79). The SHRs for progression to ESKD also increased as the number of MetS components increased. Additionally, adding the IFTA scores improved the prognostic power of a model that only contained MetS and clinical covariates for predicting future ESKD.

CONCLUSION

MetS is an independent prognostic predictor of ESKD in patients with T2D and DN, while adding the IFTA scores increased the prognostic value of MetS for renal outcome.

Cholesterol Metabolism in Chronic Kidney Disease: Physiology, Pathologic Mechanisms, and Treatment

High plasma levels of lipids and/or lipoproteins are risk factors for atherosclerosis, nonalcoholic fatty liver disease (NAFLD), obesity, and diabetes. These four conditions have also been identified as risk factors leading to the development of chronic kidney disease (CKD). Although many pathways that generate high plasma levels of these factors have been identified, most clinical and physiologic dysfunction results from aberrant assembly and secretion of lipoproteins. The results of several published studies suggest that elevated levels of low-density lipoprotein (LDL)-cholesterol are a risk factor for atherosclerosis, myocardial infarction, coronary artery calcification associated with type 2 diabetes, and NAFLD. Cholesterol metabolism has also been identified as an important pathway contributing to the development of CKD; clinical treatments designed to alter various steps of the cholesterol synthesis and metabolism pathway are currently under study. Cholesterol synthesis and catabolism contribute to a multistep process with pathways that are regulated at the cellular level in renal tissue. Cholesterol metabolism may also be regulated by the balance between the influx and efflux of cholesterol molecules that are capable of crossing the membrane of renal proximal tubular epithelial cells and podocytes. Cellular accumulation of cholesterol can result in lipotoxicity and ultimately kidney dysfunction and failure. Thus, further research focused on cholesterol metabolism pathways will be necessary to improve our understanding of the impact of cholesterol restriction, which is currently a primary intervention recommended for patients with dyslipidemia.

High-Fat Diet-Induced Renal Proximal Tubular Inflammatory Injury: Emerging Risk Factor of Chronic Kidney Disease

Nowadays, with the improvements in living standards and changes in living habits, high-fat diet (HFD) has become much more common in the populations worldwide. Recent studies have shown that HFD could induce lipid accumulation, and structural and functional abnormalities, accompanied by the release of large amounts of pro-inflammatory cytokines, in proximal tubular epithelial cells (PTECs). These findings indicate that, as an emerging risk factor, PTEC injury-induced by HFD may be closely related to inflammation; however, the potential mechanisms underlying this phenomenon is still not well-known, but may involve the several inflammatory pathways, including oxidative stress-related signaling pathways, mitochondrial dysfunction, the myeloid differentiation factor 2/Toll like receptor 4 (MD2/TLR4) signaling pathway, the ERK1/2-kidney injury molecule 1 (KIM-1)-related pathway, and nuclear factor-κB (NF-κB) activation, etc., and the detailed molecular mechanisms underlying these pathways still need further investigated in the future. Based on lipid abnormalities-induced inflammation is closely related to the development and progression of chronic kidney disease (CKD), to summarize the potential mechanisms underlying HFD-induced renal proximal tubular inflammatory injury, may provide novel approaches for CKD treatment.

Lipidomic and Metabolomic Signature of Progression of Chronic Kidney Disease in Patients with Severe Obesity

Severe obesity is a major risk for chronic kidney disease (CKD). Early detection and careful monitoring of renal function are critical for the prevention of CKD during obesity, since biopsies are not performed in patients with CKD and diagnosis is dependent on the assessment of clinical parameters. To explore whether distinct lipid and metabolic signatures in obesity may signify early stages of pathogenesis toward CKD, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-high resolution accurate mass-mass spectrometry (GC-HRAM-MS) analyses were performed in the serum and the urine of severely obese patients with and without CKD. Moreover, the impact of bariatric surgery (BS) in lipid and metabolic signature was also studied, through LC-MS and GC-HRAM-MS analyses in the serum and urine of patients with severe obesity and CKD before and after undergoing BS. Regarding patients with severe obesity and CKD compared to severely obese patients without CKD, serum lipidome analysis revealed significant differences in lipid signature. Furthermore, serum metabolomics profile revealed significant changes in specific amino acids, with isoleucine and tyrosine, increased in CKD patients compared with patients without CKD. LC-MS and GC-HRAM-MS analysis in serum of patients with severe obesity and CKD after BS showed downregulation of levels of triglycerides (TGs) and diglycerides (DGs) as well as a decrease in branched-chain amino acid (BCAA), lysine, threonine, proline, and serine. In addition, BS removed most of the correlations in CKD patients against biochemical parameters related to kidney dysfunction. Concerning urine analysis, hippuric acid, valine and glutamine were significantly decreased in urine from CKD patients after surgery. Interestingly, bariatric surgery did not restore all the lipid species, some of them decreased, hence drawing attention to them as potential targets for early diagnosis or therapeutic intervention. Results obtained in this study would justify the use of comprehensive mass spectrometry-based lipidomics to measure other lipids aside from conventional lipid profiles and to validate possible early markers of risk of CKD in patients with severe obesity.

Spectrally and Time-Resolved Fluorescence Imaging of 22-NBD-Cholesterol in Human Peripheral Blood Mononuclear Cells in Chronic Kidney Disease Patients

The interaction of the fluorescent probe 22-NBD-cholesterol with membranes of human peripheral blood mononuclear cells (PBMC) was tested by time- and spectrally resolved fluorescence imaging to monitor the disturbance of lipid metabolism in chronic kidney disease (CKD) and its treatment with statins. Blood samples from healthy volunteers (HV) and CKD patients, either treated or untreated with statins, were compared. Spectral imaging was done using confocal microscopy at 16 spectral channels in response to 458 nm excitation. Time-resolved imaging was achieved by time-correlated single photon counting (TCSPC) following excitation at 475 nm. The fluorescence of 22-NBD-cholesterol was mostly integrated into plasmatic membrane and/or intracellular membrane but was missing from the nuclear region. The presence of two distinct spectral forms of 22-NBD-cholesterol was uncovered, with significant variations between studied groups. In addition, two fluorescence lifetime components were unmasked, changing in CKD patients treated with statins. The gathered results indicate that 22-NBD-cholesterol may serve as a tool to study changes in the lipid metabolism of patients with CKD to monitor the effect of statin treatment.

Lipoprotein Glomerulopathy-Like Lesions in Atherosclerotic Mice Defected With HDL Receptor SR-B1

High-density lipoprotein (HDL) homeostasis is important in maintaining both cardiovascular and renal health. Scavenger receptor class B type 1 (SR-B1), the major HDL receptor in mammals, plays a crucial role in reverse cholesterol transport and HDL metabolism. Evidence from mouse study has well demonstrated that HDL disorders caused by Srb1 inactivation accelerate atherosclerosis and even induce lethal cardiovascular diseases. However, the renal consequences of Srb1 dysfunction are still unknown. Here we explored this issue in both Srb1 knockout (Srb1-/-) mice and atherosclerotic low-density lipoprotein receptor knockout (Ldlr-/-) mice with Srb1 deletion. Our data showed that no apparent renal damage was observed in 5-month-old Srb1-/- mice fed on standard rodent chow diet as well as Srb1-/- mice fed on a high-fat diet (HFD) for 12 weeks. However, 5-month-old Srb1/Ldlr-/- mice fed on rodent chow had increased urinary albumin excretion and developed spontaneous intraglomerular Oil-red O (ORO)-positive lipoprotein deposition that is similar to lesions observed in human lipoprotein glomerulopathy (LPG). HFD feeding accelerated LPG-like lesions in Srb1/Ldlr-/- mice, inducing severe proteinuria and significantly promoting intraglomerular ORO-positive lipoprotein deposition. Interestingly, probucol reversed HFD-induced HDL disorders and almost fully abrogated LPG-like lesions in Srb1/Ldlr-/- mice. In conclusion, the present study demonstrates that SR-B1 dysfunction leads to LPG-like lesions in atherosclerotic mice, which could be rescued by probucol. SR-B1 loss-of-function mutant carriers therefore might be susceptible to developing metabolic nephropathy in addition to cardiovascular diseases, and probucol might be a potential therapeutics.

Dyslipidemia in Chronic Kidney Disease: Contemporary Concepts and Future Therapeutic Perspectives

BACKGROUND

Chronic kidney disease (CKD) is an increasingly prevalent disease state met with great morbidity and mortality primarily resulting from the high incidence of adverse cardiovascular outcomes. Therapeutic strategies in this patient population aim at controlling modifiable cardiovascular risk factors, including dyslipidemia.

SUMMARY

In this review article, we first provide the latest pathophysiologic evidence regarding the altered dyslipidemia pattern in CKD, followed by its contemporary management according to the latest guidelines. Moreover, we present the current progress regarding the emerging therapeutic strategies. Key Messages: The presence of renal impairment leads to alterations in cholesterol structure, metabolism, and reverse transport paired with increased oxidative stress. Statins remain the cornerstone of dyslipidemia management in patients with kidney dysfunction who are at risk for cardiovascular events. However, their efficacy is debatable in end-stage renal disease under renal replacement therapy. Therefore, novel treatment approaches aiming at hypertriglyceridemia, proprotein convertase subtilisin/kexin type 9, and lipoprotein(a) are under rigorous investigation while the research of gut microbiome might provide additional mechanistic and therapeutic insight.

Inflammation Alters Relationship Between High-Density Lipoprotein Cholesterol and Cardiovascular Risk in Patients With Chronic Kidney Disease: Results From KNOW-CKD

Background

The function of high‐density lipoprotein can change from protective to proatherosclerotic under inflammatory conditions. Herein, we studied whether inflammation could modify the relationship between high‐density lipoprotein level and risk of adverse outcomes in patients with chronic kidney disease .

Methods and Results

In total, 1864 patients from the prospective KNOW‐CKD (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) were enrolled. The main predictor was high‐density lipoprotein cholesterol (HDL‐C) level. Presence of inflammation was defined by hs‐CRP (high‐sensitivity C‐reactive protein) level of ≥1.0 mg/L. The primary outcome was extended major adverse cardiovascular events. During 9231.2 person‐years of follow‐up, overall incidence of the primary outcome was 15.8 per 1000 person‐years. In multivariable Cox analysis after adjusting for confounders, HDL‐C level was not associated with the primary outcome. There was a significant interaction between the inflammatory status and HDL‐C for risk of extended major adverse cardiovascular events (P=0.003). In patients without inflammation, the hazard ratios (HRs) (95% CIs) for HDL‐C levels <40, 50 to 59, and ≥60 mg/dL were 1.10 (0.50–1.82), 0.95 (0.50–1.82), and 0.42 (0.19–0.95), respectively, compared with HDL‐C of 40 to 49 mg/dL. However, the significant association for HDL‐C ≥60 mg/dL was not seen after Bonferroni correction. In patients with inflammation, we observed a trend toward increased risk of extended major adverse cardiovascular events in higher HDL‐C groups (HRs [95% CIs], 0.73 [0.37–1.43], 1.24 [0.59–2.61], and 1.56 [0.71–3.45], respectively), but without statistical significance.

Conclusions

The association between HDL‐C level and adverse cardiovascular outcomes showed reverse trends based on inflammation status in Korean patients with chronic kidney disease.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT01630486.

High-Density Lipoproteins in Kidney Disease

Decades of epidemiological studies have established the strong inverse relationship between high-density lipoprotein (HDL)-cholesterol concentration and cardiovascular disease. Recent evidence suggests that HDL particle functions, including anti-inflammatory and antioxidant functions, and cholesterol efflux capacity may be more strongly associated with cardiovascular disease protection than HDL cholesterol concentration. These HDL functions are also relevant in non-cardiovascular diseases, including acute and chronic kidney disease. This review examines our current understanding of the kidneys’ role in HDL metabolism and homeostasis, and the effect of kidney disease on HDL composition and functionality. Additionally, the roles of HDL particles, proteins, and small RNA cargo on kidney cell function and on the development and progression of both acute and chronic kidney disease are examined. The effect of HDL protein modification by reactive dicarbonyls, including malondialdehyde and isolevuglandin, which form adducts with apolipoprotein A-I and impair proper HDL function in kidney disease, is also explored. Finally, the potential to develop targeted therapies that increase HDL concentration or functionality to improve acute or chronic kidney disease outcomes is discussed.

Association between monocyte count to high-density lipoprotein cholesterol ratio and mortality in patients undergoing peritoneal dialysis

BACKGROUND AND AIMS

Previous studies had demonstrated that elevated monocyte count to high-density lipoprotein cholesterol ratio (MHR), a novel marker of inflammation, was associated with higher cardiovascular events and mortality in patients with pre-dialysis chronic kidney disease, diabetes, and coronary heart disease. However, the association between MHR and mortality in patients undergoing peritoneal dialysis (PD) has received little attention. The aim of this study was to investigate the association between MHR and all-cause and cardiovascular mortality in PD patients.

METHODS AND RESULTS

In this single center retrospective cohort study, PD patients who had catheter insertion in our PD center from January 1, 2006 to December 31, 2016 were enrolled. All patients were divided into three groups according to the tertiles of baseline MHR levels and followed up until December 31, 2018. The associations of MHR levels with all-cause and cardiovascular mortality were assessed by using Cox proportional hazards models. Of 1584 patients, mean age was 46.02 ± 14.65 years, 60.1% were male, and 24.2% had diabetes. The mean MHR level was 0.39 ± 0.23. During a median follow up time of 45.6 (24.6-71.8) months, 349 patients died, and 181 deaths were caused by cardiovascular disease. After adjusting for confounders, the highest MHR tertile was significantly associated with all-cause and cardiovascular mortality with a hazard ratio of 1.43 (95%CI = 1.06-1.93, P = 0.019), 1.54 (95%CI = 1.01-2.35, P = 0.046), respectively.

CONCLUSION

Higher MHR level was an independent risk factor for all-cause and cardiovascular mortality in PD patients.

New Pandemic: Obesity and Associated Nephropathy

Incidence of obesity related renal disorders have increased 10-folds in recent years. One of the consequences of obesity is an increased glomerular filtration rate (GFR) that leads to the enlargement of the renal glomerulus, i.e., glomerulomegaly. This heightened hyper-filtration in the setting of type 2 diabetes irreparably damages the kidney and leads to progression of end stage renal disease (ESRD). The patients suffering from type 2 diabetes have progressive proteinuria, and eventually one third of them develop chronic kidney disease (CKD) and ESRD. For ameliorating the progression of CKD, inhibitors of renin angiotensin aldosterone system (RAAS) seemed to be effective, but on a short-term basis only. Long term and stable treatment strategies like weight loss via restricted or hypo-caloric diet or bariatric surgery have yielded better promising results in terms of amelioration of proteinuria and maintenance of normal GFR. Body mass index (BMI) is considered as a traditional marker for the onset of obesity, but apparently, it is not a reliable indicator, and thus there is a need for more precise evaluation of regional fat distribution and amount of muscle mass. With respect to the pathogenesis, recent investigations have suggested perturbation in fatty acid and cholesterol metabolism as the critical mediators in ectopic renal lipid accumulation associated with inflammation, increased generation of ROS, RAAS activation and consequential tubulo-interstitial injury. This review summarizes the renewed approaches for the obesity assessment and evaluation of the pathogenesis of CKD, altered renal hemodynamics and potential therapeutic targets.

Multifaced Roles of HDL in Sepsis and SARS-CoV-2 Infection: Renal Implications

High-density lipoproteins (HDLs) are a class of blood particles, principally involved in mediating reverse cholesterol transport from peripheral tissue to liver. Omics approaches have identified crucial mediators in the HDL proteomic and lipidomic profile, which are involved in distinct pleiotropic functions. Besides their role as cholesterol transporter, HDLs display anti-inflammatory, anti-apoptotic, anti-thrombotic, and anti-infection properties. Experimental and clinical studies have unveiled significant changes in both HDL serum amount and composition that lead to dysregulated host immune response and endothelial dysfunction in the course of sepsis. Most SARS-Coronavirus-2-infected patients admitted to the intensive care unit showed common features of sepsis disease, such as the overwhelmed systemic inflammatory response and the alterations in serum lipid profile. Despite relevant advances, episodes of mild to moderate acute kidney injury (AKI), occurring during systemic inflammatory diseases, are associated with long-term complications, and high risk of mortality. The multi-faceted relationship of kidney dysfunction with dyslipidemia and inflammation encourages to deepen the clarification of the mechanisms connecting these elements. This review analyzes the multifaced roles of HDL in inflammatory diseases, the renal involvement in lipid metabolism, and the novel potential HDL-based therapies.

Association Between Renal Dysfunction and Low HDL Cholesterol Among the Elderly in China

Objective: Chronic kidney disease (CKD) and cardiovascular disease (CVD) have a high morbidity and mortality among the elderly. Low levels of high-density lipoprotein cholesterol (HDL-C), a traditional risk marker for CVD, are common in CKD patients. Little is known about the association of low HDL-C with renal dysfunction in the community dwelling population. Methods: This was a population-based cross-sectional study included 4,753 participants enrolled in a prospective study, the Shanghai Elderly Cardiovascular Health (SHECH) study. Estimated glomerular filtration rate (eGFR), calculated by the Chinese Modification of Diet in Renal Disease (C-MDRD equation), was used to assess renal dysfunction. Associations between renal dysfunction and low HDL-C were evaluated using multiple logistic regression models and restricted cubic splines. Results: Of 4,649 individuals who met inclusion criteria, 620 (13.34%) had low HDL-C at <40 mg/dl. In the fully adjusted model, lower eGFR of <60 ml/min/1.73 m² (OR, 2.03; 95% CI, 1.21-3.43) and marginal eGFR of 60 to 90 ml/min/1.73 m² (OR, 1.26; 95% CI, 1.01-1.58) were significantly associated with low HDL-C, compared with normal eGFR of ≥90 ml/min/1.73 m². Moreover, consistent findings were obtained in subsidiary analyses using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. Fully adjusted cubic spline models indicated a significant dose-response relationship between eGFR and low HDL-C (P for non-linearity, 0.356). Conclusion: In this general elderly population, renal dysfunction was independently and significantly associated with low HDL-C, and the prevalence of low HDL-C increased with decreasing eGFR, such that even slight changes in renal function may be associated with altered lipid levels.

Serum and urine ANGPTL8 expression levels are associated with hyperlipidemia and proteinuria in primary nephrotic syndrome

Background

This study aimed to investigate the expression characteristics of ANGPTL8 in patients with primary nephrotic syndrome and its possible correlation with hyperlipidemia and proteinuria.

Methods

ANGPTL8 levels were determined using an enzyme-linked immunosorbent assay in 133 subjects with PNS and 60 healthy controls.

Results

Compared with healthy controls, subjects with primary nephrotic syndrome had higher levels of serum and urine ANGPTL8 (P < 0.001). In primary nephrotic syndrome patients, serum ANGPTL8 was positively correlated with cholesterol (r = 0.209, P < 0.05) and triglycerides (r = 0.412, P < 0.001), while there was no correlation with 24 hUTP. Urine ANGPTL8 was positively correlated with high-density lipoprotein cholesterol (r = 0.181, P < 0.05) and was significantly negatively correlated with creatinine (r = − 0.323, P < 0.001), eGFR (r = − 0, P < 0.001) and 24 hUTP (r = − 0.268, P = 0.002). Interestingly, the urine ANGPTL8 concentrations in membranous nephropathy and mesangial proliferative glomerulonephritis pathological types were different.

Conclusions

Serum and urine ANGPTL8 levels in primary nephrotic syndrome patients were correlated with blood lipid levels and proteinuria, respectively, suggesting that ANGPTL8 may play a role in the development of primary nephrotic syndrome hyperlipidemia and proteinuria.

Lipoprotein Abnormalities in Chronic Kidney Disease and Renal Transplantation

Chronic kidney disease (CKD) is one of the most important risk factors for cardiovascular disease (CVD). Despite the kidney having no direct implications for lipoproteins metabolism, advanced CKD dyslipidemia is usually present in patients with CKD, and the frequent lipid and lipoprotein alterations occurring in these patients play a role of primary importance in the development of CVD. Although hypertriglyceridemia is the main disorder, a number of lipoprotein abnormalities occur in these patients. Different enzymes pathways and proteins involved in lipoprotein metabolism are impaired in CKD. In addition, treatment of uremia may modify the expression of lipoprotein pattern as well as determine acute changes. In renal transplantation recipients, the main lipid alteration is hypercholesterolemia, while hypertriglyceridemia is less pronounced. In this review we have analyzed lipid and lipoprotein disturbances in CKD and also their relationship with progression of renal disease. Hypolipidemic treatments may also change the natural history of CVD in CKD patients and may represent important strategies in the management of CKD patients.

Novel Predictors and Risk Score of Treatment Failure in Peritoneal Dialysis-Related Peritonitis

Objective: Peritonitis is a severe complication in peritoneal dialysis (PD). This study was performed to identify predictors and establish a risk score for treatment failure in peritonitis patients.

Methods: A single-center, retrospective observational study was conducted. The basic demographic characteristics, clinical and laboratory data of all patients with peritonitis during the study period were documented and analyzed. Multivariate logistic regression was applied to examine independent predictors of treatment failure, and a risk prediction score was established.

Results: Three hundred fourteen episodes experienced by 241 patients were included in the final analysis. Logistic regression analysis indicated that PD duration (OR 1.017; P 0.005), fibrinogen (OR 1.327; P 0.021), high-density lipoprotein (OR 0.443; P 0.032), fungal infection (OR 63.413; P < 0.001), intestinal obstruction (OR 5.186, P 0.007), and diabetes mellitus (OR 2.451; P 0.018), hemodialysis history (OR 2.804, P 0.006) were independent predictors of treatment failure. The risk prediction score system showed a good calibration (P > 0.05) and discrimination (AUROC 0.80, P < 0.001).

Conclusions: Fibrinogen, PD duration, fungal infection, hemodialysis history, concurrent intestinal obstruction, or diabetes mellitus were independent risk factors for a poor peritonitis outcome, while the high-density lipoprotein was a protective factor. This novel risk prediction score system may be used to predict a high risk of treatment failure effectively.

Correlation between plasma proprotein convertase subtilisin/kexin type 9 and blood lipids in patients with newly diagnosed primary nephrotic syndrome

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a major post-transcriptional regulator of low-density lipoprotein receptor degradation. Recently, PCSK9 was shown to be overexpressed by liver cells in rats with proteinuria. However, the levels of PCSK9 in newly diagnosed primary nephrotic syndrome (PNS) patients and correlations involving PCSK9 and blood lipids are not clearly understood.

Methods

One hundred and sixteen patients who were newly diagnosed with PNS were enrolled in this study.

Results

Plasma PCSK9 levels in PNS patients were significantly higher than those in healthy controls [310.86 (250.87, 390.25) ng/ml vs 255.67 (202.26, 320.26) ng/ml, p = 0.002]. Plasma PCSK9 in PNS patients was positively correlated with total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) (γ = 0.246, p = 0.008, and γ = 0.183, p = 0.049). When plasma PCSK9 was >267.60 ng/ml, the risk of developing hypercholesterolemia significantly increased in PNS patients (OR = 6.40, 95% CI 2.06–19.87, p = 0.001). When plasma PCSK9 was >255.05 ng/ml, the risk of developing higher levels of LDL-C significantly increased in PNS patients (OR = 3.83, 95%CI 1.25–11.68, p = 0.018).

Conclusions

Plasma PCSK9 levels in newly diagnosed PNS patients were markedly increased, and elevated PCSK9 abundance was positively correlated with elevated serum TC and LDL-C levels, suggesting that PCSK9 may emerge as a novel therapeutic target in NS-associated hypercholesterolemia.

Causal effect between total cholesterol and HDL cholesterol as risk factors for chronic kidney disease: a mendelian randomization study

Background

While observational studies show an association between serum lipid levels and cardiovascular disease (CVD), intervention studies that examine the preventive effects of serum lipid levels on the development of CKD are lacking.

Methods

To estimate the role of serum lipid levels in the etiology of CKD, we conducted a two-sample mendelian randomization (MR) study on serum lipid levels. Single nucleotide polymorphisms (SNPs), which were significantly associated genome-wide with serum lipid levels from the GLGC and CKDGen consortium genome-wide association study (GWAS), including total cholesterol (TC, n = 187,365), triglyceride (TG, n = 177,861), HDL cholesterol (HDL-C, n = 187,167), LDL cholesterol (LDL-C, n = 173,082), apolipoprotein A1 (ApoA1, n = 20,687), apolipoprotein B (ApoB, n = 20,690) and CKD (n = 117,165), were used as instrumental variables. None of the lipid-related SNPs was associated with CKD (all P > 0.05).

Results

MR analysis genetically predicted the causal effect between TC/HDL-C and CKD. The odds ratio (OR) and 95% confidence interval (CI) of TC within CKD was 0.756 (0.579 to 0.933) (P = 0.002), and HDL-C was 0.85 (0.687 to 1.012) (P = 0.049). No causal effects between TG, LDL-C- ApoA1, ApoB and CKD were observed. Sensitivity analyses confirmed that TC and HDL-C were significantly associated with CKD.

Conclusions

The findings from this MR study indicate causal effects between TC, HDL-C and CKD. Decreased TC and elevated HDL-C may reduce the incidence of CKD but need to be further confirmed by using a genetic and environmental approach.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-020-02228-3.

Protein convertase subtilisin/kexin type 9 biology in nephrotic syndrome: implications for use as therapy

Low-density lipoprotein cholesterol (LDL-C) levels almost constantly increased in patients with nephrotic syndrome (NS). Protein convertase subtilisin/kexin type 9 (PCSK9) [accelerates LDL-receptor (LDL-R) degradation] is overexpressed by liver cells in NS. Their levels, correlated inversely to LDL-R expression and directly to LDL-C, seem to play a central role in hypercholesterolaemia in NS. Hypersynthesis resulting from sterol regulatory element-binding protein dysfunction, hyperactivity induced by c-inhibitor of apoptosis protein expressed in response to stimulation by tumour necrosis factor-α produced by damaged podocytes and hypo-clearance are the main possible mechanisms. Increased LDL-C may damage all kidney cell populations (podocytes, mesangial and tubular cells) in a similar manner. Intracellular cholesterol accumulation produces oxidative stress, foam cell formation and apoptosis, all favoured by local inflammation. The cumulative effect of cellular lesions is worsened proteinuria and kidney function loss. Accordingly, NS patients should be considered high risk and treated by lowering LDL-C. However, there is still not enough evidence determining whether lipid-lowering agents are helpful in managing dyslipidaemia in NS. Based on good efficacy and safety proved in the general population, therapeutic modulation of PCSK9 via antibody therapy might be a reasonable solution. This article explores the established and forthcoming evidence implicating PCSK9 in LDL-C dysregulation in NS.

RNA Interference Targeting Liver Angiopoietin-Like Protein 3 Protects from Nephrotic Syndrome in a Rat Model Via Amelioration of Pathologic Hypertriglyceridemia

Nephrotic syndrome (NS) is associated with metabolic perturbances including profound dyslipidemia characterized by hypercholesterolemia and hypertriglyceridemia. A major underlying mechanism of hypertriglyceridemia in NS is lipoprotein lipase (LPL) deficiency and dysfunction. There is emerging evidence that elevated angiopoietin-like protein 3 (ANGPTL3), an LPL inhibitor that is primarily expressed and secreted by hepatocytes, may be in part responsible for these findings. Furthermore, there is evidence pointing to the contribution of ANGPTL3 to the pathogenesis of proteinuria in NS. Therefore, we hypothesized that inhibition of hepatic ANGPTL3 by RNA interference will ameliorate dyslipidemia and other symptoms of NS and pave the way for a new therapeutic strategy. To this end, we used a subcutaneously delivered, GalNAc (N-Acetylgalactosamine)-conjugated small interfering RNA (siRNA) to selectively target and suppress liver Angptl3 in rats with puromycin-induced NS, which exhibits clinical features of NS including proteinuria, hypoalbuminemia, hyperlipidemia, and renal histologic abnormalities. The study demonstrated that siRNA-mediated knockdown of the liver Angptl3 relieved its inhibitory effect on LPL and significantly reduced hypertriglyceridemia in nephrotic rats. This was accompanied by diminished proteinuria and hypoalbuminemia, which are the hallmarks of NS, and significant attenuation of renal tissue inflammation and oxidative stress. Taken together, this study confirmed the hypothesis that suppression of Angptl3 is protective in NS and points to the possibility that the use of RNA interference to suppress hepatic Angptl3 can serve as a novel therapeutic strategy for NS. SIGNIFICANCE STATEMENT: The current standard of care for mitigating nephrotic dyslipidemia in nephrotic syndrome is statins therapy. However, the efficacy of statins and its safety in the context of impaired kidney function is not well established. Here, we present an alternate therapeutic approach by using siRNA targeting Angptl3 expressed in hepatocytes. As the liver is the major source of circulating Angptl3, siRNA treatment reduced the profound hypertriglyceridemia in a rat model of nephrotic syndrome and was also effective in improving kidney and cardiac function.

Berberine alleviates palmitic acid‑induced podocyte apoptosis by reducing reactive oxygen species‑mediated endoplasmic reticulum stress

Lipid accumulation in podocytes can lead to the destruction of cellular morphology, in addition to cell dysfunction and apoptosis, which is a key factor in the progression of chronic kidney disease (CKD). Berberine (BBR) is an isoquinoline alkaloid extracted from medicinal plants such as Coptis chinensis, which has been reported to have a lipid-lowering effect and prevent CKD progression. Therefore, the present study aimed to investigate the effect of BBR on palmitic acid (PA)-induced podocyte apoptosis and its specific mechanism using an in vitro model. Cell death was measured using the Cell Counting Kit-8 colorimetric assay. Cell apoptotic rate was assessed by flow cytometry. The expression of endoplasmic reticulum (ER) stress- and apoptosis-related proteins was detected by western blotting or immunofluorescence. Reactive oxygen species (ROS) were evaluated by 2′,7′-dichlorofluorescein diacetate fluorescence staining. The results of the present study revealed that BBR treatment decreased PA-induced podocyte apoptosis. In addition, 4-phenylbutyric acid significantly reduced PA-induced cell apoptosis and the expression of ER stress-related proteins, which indicated that ER stress was involved in PA-induced podocyte apoptosis. In addition, N-acetylcysteine inhibited PA-induced excessive ROS production, ER stress and cell apoptosis of podocytes. BBR also significantly reduced PA-induced ROS production and ER stress in podocytes. These results suggested that PA mediated podocyte apoptosis through enhancing ER stress and the production of ROS. In conclusion, BBR may protect against PA-induced podocyte apoptosis, and suppression of ROS-dependent ER stress may be the key mechanism underlying the protective effects of BBR.

Dyslipidemia and cardiovascular health in childhood nephrotic syndrome

Children with steroid-resistant nephrotic syndrome (SRNS) are exposed to multiple cardiovascular risk factors predisposing them to accelerated atherosclerosis. This risk is negligible in steroid-sensitive nephrotic syndrome, but a substantial proportion of children with SRNS progress to chronic kidney disease, exacerbating the already existing cardiovascular risk. While dyslipidemia is an established modifiable risk factor for cardiovascular disease in adults with NS, it is uncertain to what extent analogous risks exist for children. There is increasing evidence of accelerated atherosclerosis in children with persistently high lipid levels, especially in refractory NS. Abnormalities of lipid metabolism in NS include hypertriglyceridemia and hypercholesterolemia due to elevated apolipoprotein B-containing lipoproteins, decreased lipoprotein lipase and hepatic lipase activity, increased hepatic PCSK9 levels, and reduced hepatic uptake of high-density lipoprotein. Existing guidelines for the management of dyslipidemia in children may be adapted to target lower lipid levels in children with NS, but they will most likely require both lifestyle modifications and pharmacological therapy. While there is a lack of data from randomized controlled trials in children with NS demonstrating the benefit of lipid-lowering drugs, therapies including statins, bile acid sequestrants, fibrates, ezetimibe, and LDL apheresis have all been suggested and/or utilized. However, concerns with the use of lipid-lowering drugs in children include unclear side effect profiles and unknown long-term impacts on neurological development and puberty. The recent introduction of anti-PCSK9 monoclonal antibodies and other therapies targeted to the molecular mechanisms of lipid transport disrupted in NS holds promise for the future treatment of dyslipidemia in NS.