The effect of chronic kidney disease on lipid metabolism

Combined UPLC-QqQ-MS/MS and AP-MALDI Mass Spectrometry Imaging Method for Phospholipidomics in Obese Mouse Kidneys: Alleviation by Feeding Sea Cucumber Phospholipids

Sea cucumber phospholipids have ameliorative effects on various diseases related to lipid metabolism. However, it is unclear whether it can ameliorate obesity-associated glomerulopathy (ORG) induced by a high-fat diet (HFD). The present study applied UPLC-QqQ-MS/MS and atmospheric pressure matrix-assisted laser desorption ionization mass spectrometry imaging (AP-MALDI MSI) to investigate the effects of sea cucumber phospholipids, including plasmalogen PlsEtn and plasmanylcholine PakCho, on phospholipid profiles in the HFD-induced ORG mouse kidney. Quantitative analysis of 135 phospholipids revealed that PlsEtn and PakCho significantly modulated phospholipid levels. Notably, PlsEtn modulated kidney overall phospholipids better than PakCho. Imaging the "space-content" of 9 phospholipids indicated that HFD significantly increased phospholipid content within the renal cortex. Furthermore, PlsEtn and PakCho significantly decreased the expression of transport-related proteins CD36, while elevating the expression of fatty acid β-oxidation-related protein PPAR-α in the renal cortex. In conclusion, sea cucumber phospholipids reduced renal lipid accumulation, ameliorated renal damage, effectively regulated the content and distribution of renal phospholipids, and improved phospholipid homeostasis, exerting an anti-OGR effect.

Sodium-Glucose Cotransporter Inhibitors: Cellular Mechanisms Involved in the Lipid Metabolism and the Treatment of Chronic Kidney Disease Associated with Metabolic Syndrome

Metabolic syndrome (MetS) is a multifactorial condition that significantly increases the risk of cardiovascular disease and chronic kidney disease (CKD). Recent studies have emphasized the role of lipid dysregulation in activating cellular mechanisms that contribute to CKD progression in the context of MetS. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have demonstrated efficacy in improving various components of MetS, including obesity, dyslipidemia, and insulin resistance. While SGLT2i have shown cardioprotective benefits, the underlying cellular mechanisms in MetS and CKD remain poorly studied. Therefore, this review aims to elucidate the cellular mechanisms by which SGLT2i modulate lipid metabolism and their impact on insulin resistance, mitochondrial dysfunction, oxidative stress, and CKD progression. We also explore the potential benefits of combining SGLT2i with other antidiabetic drugs. By examining the beneficial effects, molecular targets, and cytoprotective mechanisms of both natural and synthetic SGLT2i, this review provides a comprehensive understanding of their therapeutic potential in managing MetS-induced CKD. The information presented here highlights the significance of SGLT2i in addressing the complex interplay between metabolic dysregulation, lipid metabolism dysfunction, and renal impairment, offering clinicians and researchers a valuable resource for developing improved treatment strategies and personalized approaches for patients with MetS and CKD.

Rheumatoid arthritis and the risk of chronic kidney diseases: a Mendelian randomization study

Background

The extra-articular lesions of rheumatoid arthritis (RA) are reported to involve multiple organs and systems throughout the body, including the heart, kidneys, liver, and lungs. This study assessed the potential causal relationship between RA and the risk of chronic kidney diseases (CKDs) using the Mendelian randomization (MR) analysis.

Method

Independent genetic instruments related to RA and CKD or CKD subtypes at the genome-wide significant level were chosen from the publicly shared summary-level data of genome-wide association studies (GWAS). Then, we obtained some single-nucleotide polymorphisms (SNPs) as instrumental variables (IVs), which are associated with RA in individuals of European origin, and had genome-wide statistical significance (p5 × 10-8). The inverse-variance weighted (IVW) method was the main analysis method in MR analysis. The other methods, such as weighted median, MR-Egger, simple mode, and weighted mode were used as supplementary sensitivity analyses. Furthermore, the levels of pleiotropy and heterogeneity were assessed using Cochran's Q test and leave-one-out analysis. Furthermore, the relevant datasets were obtained from the Open GWAS database.

Results

Using the IVW method, the main method in MR analysis, the results showed that genetically determined RA was associated with higher risks of CKD [odds ratio (OR): 1.22, 95% confidence interval (CI) 1.13-1.31; p < 0.001], glomerulonephritis (OR: 1.23, 95% CI 1.15-1.31; p < 0.000), amyloidosis (OR = 1.43, 95% CI 1.10-1.88, p < 0.001), and renal failure (OR = 1.18, 95% CI 1.00-1.38, p < 0.001). Then, using multiple MR methods, it was confirmed that the associations persisted in sensitivity analyses, and no pleiotropy was detected.

Conclusion

The findings revealed a causal relationship between RA and CKD, including glomerulonephritis, amyloidosis, and renal failure. Therefore, RA patients should pay more attention to monitoring their kidney function, thus providing the opportunity for earlier intervention and lower the risk of progression to CKDs.

Farnesoid X receptor activation protects against renal fibrosis via modulation of β-catenin signaling

OBJECTIVE

Activation of farnesoid X receptor (FXR), a bile acid nuclear receptor, may be implicated in the pathophysiology of diabetic nephropathy. We explored a possible role for FXR activation in preventing renal fibrosis in high fat diet (HFD)-fed mice.

METHODS

We investigated the effects of HFD on mouse kidney and renal tubular epithelial cells both in vivo and in vitro, and observed the changes of FXR and β-catenin pathway. FXR agonist was also used to alleviate this HFD-induced effect, and the interaction between FXR and β-catenin was further verified.

RESULTS

Mice were fed by a 60% kcal fat diet for 20 weeks developed the typical traits of metabolic syndrome with subsequent renal lipid accumulation and renal injury. Treatment with the FXR agonist CDCA or GW4064 decreased body weight, renal lipid accumulation, as well as renal injury. Moreover, renal β-catenin signaling was activated and improved with FXR-agonist treatment in HFD-fed mice. To examine whether FXR affected β-catenin signaling, and was involved in tubulo-interstitial fibrosis, we explored the FXR expression and function in ox-LDL induced-renal tubular injury. In rat proximal tubular epithelial cells (NRK-52E) stimulated by ox-LDL, FXR protein was decreased compared to control group, and phosphorylated (Ser675) β-catenin was activated by ox-LDL in a dose- and time-dependent manner. Ox-LDL enhanced α-SMA and fibronectin expressions and reduced E-cadherin levels, whereas FXR agonism or FXR overexpression inhibited fibronectin and α-SMA expressions and restored E-cadherin. Moreover, FXR agonist treatment also decreased phosphorylated (Ser675) β-catenin, nuclear translocation and β-catenin-mediated transcription induced by ox-LDL in NRK-52E cells. We showed that FXR could bind with β-catenin via the AF1 domain, and disrupt the assembly of the core β-catenin/TCF4 complex.

CONCLUSION

These experimental data suggest that FXR activation, via modulating β-catenin signaling, may contribute to attenuating the development of lipid-mediated tubulo-interstitial fibrosis.

Effects of turmeric extract supplementation on the lipid and lipoprotein subfraction profile in hemodialysis patients: A randomised, double-blind, crossover and controlled trial

Dyslipidemia is common in patients with chronic kidney disease. Curcumin, a bioactive polyphenol from Curcuma longa, can improve lipid profile. This study aims to analyze the effects of Curcuma Longa extract supplementation on lipid profile and lipoprotein subfractions in hemodialysis (HD) patients. This is a longitudinal, double-blind, washout-period randomized clinical trial. The patients were randomized into two groups: the curcumin group (n = 10) (orange and carrot juice with 2.5 g of Curcuma Longa extract) and the control group (n = 11) (juice without curcumin) 3x/w during HD sessions for 3 months. After the washout period, patients continued the supplementation as a crossover for the same period. The lipid profile was measured using enzymatic assays. The high-density lipoprotein and low-density lipoprotein subfractions analyses were performed using LipoprintTM. In the curcumin group, the triglyceride values tended to decrease with a different triglyceride variation between the pre and post-intervention for the control and curcumin groups of 38.5 (19.8) mg/dL (p = 0.06). There was no statistical difference in the others parameters. In conclusion, Curcuma longa extract may be a good nutritional strategy to reduce triglyceride plasma levels in hemodialysis patients, but it seems ineffective for the other parameter.

Safety Issues Associated With the Clinical Application of PCSK9 Inhibitors: Current Findings

Reduction in low-density lipoprotein cholesterol levels is the cornerstone of treatment and prevention of atherosclerotic cardiovascular diseases. Currently, high-intensity statins are being used as the first-line therapy to lower low-density lipoprotein cholesterol levels, as they improve the prognosis of patients with atherosclerotic cardiovascular disease and those in high-risk groups. However, in some patients, the expected reduction in cholesterol is not achieved despite aggressive treatment with statins. Moreover, some patients cannot tolerate the dosage or show poor response or compliance to statins. Therefore, combination therapies with statins and other medications should be considered. Recently, several clinical trials have shown that the use of proprotein convertase subtilisin/kexin type 9 inhibitors with or without statins and/or other lipid-lowering drugs can significantly reduce low-density lipoprotein cholesterol levels, sometimes to extremely low levels. Therefore, to facilitate appropriate prescription of these new lipid-lowering drugs, we systemically evaluated the safety issues associated with these inhibitors and extremely low low-density lipoprotein cholesterol levels.

Causal relationship between polycystic ovary syndrome and chronic kidney disease: A Mendelian randomization study

Objective

Polycystic ovary syndrome is one of the most common endocrine disorders among women of childbearing age. The relationship between polycystic ovary syndrome and chronic kidney disease remains unclear and controversial. In this study, we investigated the causal role of polycystic ovary syndrome in the development of chronic kidney disease using the two-sample Mendelian randomization method.

Methods

Public shared summary-level data was acquired from European-ancestry genome wide association studies. We finally obtained 12 single nucleotide polymorphisms as instrumental variables, which were associated with polycystic ovary syndrome in European at genome-wide significance (P < 5 × 10-8). Inverse-variance weighted method was employed in the Mendelian randomization analysis and multiple sensitivity analyses were implemented. Outcome data were obtained from the Open GWAS database.

Results

A positive causal association was observed between polycystic ovary syndrome and chronic kidney disease (odds ratio [OR]=1.180, 95% confidence interval [CI]: 1.038-1.342; P=0.010). Further analyses clarified that causal relationship exist between polycystic ovary syndrome and some serological indicators of chronic kidney disease (fibroblast growth factor 23: OR= 1.205, 95% CI: 1.031-1.409, P=0.019; creatinine: OR= 1.012, 95% CI: 1.001-1.023, P=0.035; cystatin C: OR= 1.024, 95% CI: 1.006-1.042, P=0.009). However, there was no causal association of polycystic ovary syndrome with other factors in the data sources we employed.

Conclusions

Our results indicate an important role of polycystic ovary syndrome in the development of chronic kidney disease. This study suggests that regular follow-up of renal function in patients with polycystic ovary syndrome is necessary for the early treatment of chronic kidney disease.

Rapid Molecular Evaluation of Human Kidney Tissue Sections by In Situ Mass Spectrometry and Machine Learning to Classify the Nephrotic Syndrome

Nephrotic syndrome (NS) is classified based on morphological changes of glomeruli in biopsied kidney tissues evaluated by time-consuming microscopy methods. In contrast, we employed desorption electrospray ionization mass spectrometry (DESI-MS) directly on renal biopsy specimens obtained from 37 NS patients to rapidly differentiate lipid profiles of three prevalent forms of NS: IgA nephropathy (n = 9), membranous glomerulonephritis (n = 7), and lupus nephritis (n = 8), along with other types of glomerular diseases (n = 13). As we noted molecular heterogeneity in regularly spaced renal tissue regions, multiple sections from each biopsy specimen were collected, providing a total of 973 samples for investigation. Using multivariate analysis, we report differential expressions of glycerophospholipids, sphingolipids, and glycerolipids among the above four classes of NS kidneys, which were otherwise overlooked in several past studies correlating lipid abnormalities with glomerular diseases. We developed machine learning (ML) models with the top 100 features using the support vector machine, which enabled us to discriminate the concerned glomerular diseases with 100% overall accuracy in the training, validation, and holdout test set. This DESI-MS/ML-based tissue analysis can be completed in a few minutes, in sharp contrast to a daylong procedure followed in the conventional histopathology of NS.

Altered serum metabolome associated with vascular calcification developed from CKD and the critical pathways

Introduction

Vascular calcification (VC) is more likely to be detected in the chronic kidney disease (CKD) population. The mechanism of VC development from CKD is different from that for simple VC and has always been a major research area. The aim of this study was to detect alterations in the metabolome during development of VC in CKD and to identify the critical metabolic pathways and metabolites involved in its pathogenesis.

Methods

Rats in the model group were given an adenine gavage combined with a high-phosphorus diet to imitate VC in CKD. The aorta calcium content was measured and used to divide the model group into a VC group and non-vascular calcification group (non-VC group). The control group was fed a normal rat diet and given a saline gavage. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was used to determine the altered serum metabolome in the control, VC, and non-VC groups. The identified metabolites were mapped into the Kyoto Encyclopedia of Genes and Genomes (KEGG) database (https://www.genome.jp/kegg/) for pathway and network analyses.

Result

There were 14 metabolites that changed significantly in the VC group, with three metabolic pathways playing critical roles in the pathogenesis of VC in CKD: steroid hormone biosynthesis; valine, leucine and isoleucine biosynthesis; and pantothenate and CoA biosynthesis.

Conclusion

Our results indicated changes in the expression of steroid sulfatase and estrogen sulfotransferase, and down-regulation of the in situ synthesis of estrogens in the VC group. In conclusion, the serum metabolome alters significantly during the pathogenesis of VC in CKD. The key pathways, metabolites, and enzymes we identified are worth further study and may become a promising therapeutic target for the treatment of VC in CKD.

Lipid Parameters and the Development of Chronic Kidney Disease: A Prospective Cohort Study in Middle-Aged and Elderly Chinese Individuals

Epidemiological evidence suggests that lipid parameters are related to the progression of chronic kidney disease (CKD). Nevertheless, prospective studies that comprehensively assess the effect of routinely available lipid measures on the development of CKD are lacking. The aim of this study was to longitudinally assess the influence of lipid metabolism indicators on the presence of CKD in a large community-based population. We conducted a prospective cohort study at Sun Yat-sen Memorial Hospital, China, with 5345 patients of 40 years or older. Cox regression models were conducted, and hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to assess lipid parameters and their relationship with the incidence of CKD. During the follow-up period, 340 (6.4%) subjects developed CKD. The incidence of CKD increased progressively with quartile values of triglyceride (TG), the ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (non-HDL-C/HDL-C) and the ratio of TG to HDL-C, but decreased with HDL-C quartiles (p < 0.0001 for all trends). Pearson’s correlation analysis and multiple regression analyses indicated that these parameters were also associated with various indicators of kidney function. Moreover, we found that among all the lipid parameters, TG/HDL-C emerged as the most effective predictor of CKD. In conclusion, our findings suggest that TG/HDL-C better predicts the incidence of CKD in middle-aged and elderly Chinese individuals than other lipid parameters tested in the study.

Gut-kidney axis in IgA nephropathy: Role on mesangial cell metabolism and inflammation

IgA Nephropathy (IgAN) is the commonest primary glomerular disease around the world and represents a significant cause of end-stage renal disease. IgAN is characterized by mesangial deposition of IgA-immune complexes and mesangial expansion. The pathophysiological process includes an abnormally glycosylated IgA1, which is an antigenic target. Autoantibodies specifically recognize galactose-deficient IgA1 forming immune complexes that are amplified in size by the soluble IgA Fc receptor CD89 leading to deposition in the mesangium through interaction with non-classical IgA receptors. The local production of cytokines promotes local inflammation and complement system activation, besides the stimulation of mesangial proliferation. The spectrum of clinical manifestations is quite variable from asymptomatic microscopic hematuria to rapidly progressive glomerulonephritis. Despite all the advances, the pathophysiology of the disease is still not fully elucidated. The mucosal immune system is quoted to be a factor in triggering IgAN and a "gut-kidney axis" is proposed in its development. Furthermore, many recent studies have demonstrated that food intake interferes directly with disease prognosis. In this review, we will discuss how mucosal immunity, microbiota, and nutritional status could be interfering directly with the activation of intrinsic pathways of the mesangial cells, directly resulting in changes in their function, inflammation and development of IgAN.

Chronic Kidney Disease and Its Clinical Correlates in a Rural Community in Southwestern Nigeria

Chronic kidney disease (CKD) is a burgeoning problem globally, and more than a billion adults were affected as of 2016, with 1.2 million people dying from renal failure in 2017. To arrest the seemingly relentless progression of CKD to renal failure, there is a need to detect CKD early in the community. A community-based study was carried out to look at the prevalence and risk factors of CKD. Anthropometric and other clinical variables were measured. Blood samples were taken for determining creatinine, uric acid, urea, and lipids. CKD was defined as an estimated glomerular filtration rate of ≤60 mL/min/1.73 m2. Electrocardiograms and renal ultrasound scans were performed. In total, 201 people were recruited. Those with CKD had a male:female ratio of 1:3.9 and were older. The prevalence of autosomal-dominant polycystic kidney disease and CKD was 531.9 persons/100,000 population and 46.3%, respectively. Systolic blood pressure, pulse pressure, total cholesterol, triglycerides, high-density lipoprotein (HDL), uric acid, QTc interval, and electrocardiographic left ventricular hypertrophy were higher in those with CKD. Age, female sex, and HDL were independently associated with CKD. There was a steep rise in CKD at the community level. Increased awareness of CKD and prompt interventions are therefore imperative.

Individualized prediction of chronic kidney disease for the elderly in longevity areas in China: Machine learning approaches

Background

Chronic kidney disease (CKD) has become a major public health problem worldwide and has caused a huge social and economic burden, especially in developing countries. No previous study has used machine learning (ML) methods combined with longitudinal data to predict the risk of CKD development in 2 years amongst the elderly in China.

Methods

This study was based on the panel data of 925 elderly individuals in the 2012 baseline survey and 2014 follow-up survey of the Healthy Aging and Biomarkers Cohort Study (HABCS) database. Six ML models, logistic regression (LR), lasso regression, random forests (RF), gradient-boosted decision tree (GBDT), support vector machine (SVM), and deep neural network (DNN), were developed to predict the probability of CKD amongst the elderly in 2 years (the year of 2014). The decision curve analysis (DCA) provided a range of threshold probability of the outcome and the net benefit of each ML model.

Results

Amongst the 925 elderly in the HABCS 2014 survey, 289 (18.8%) had CKD. Compared with the other models, LR, lasso regression, RF, GBDT, and DNN had no statistical significance of the area under the receiver operating curve (AUC) value (>0.7), and SVM exhibited the lowest predictive performance (AUC = 0.633, p-value = 0.057). DNN had the highest positive predictive value (PPV) (0.328), whereas LR had the lowest (0.287). DCA results indicated that within the threshold ranges of ~0-0.03 and 0.37-0.40, the net benefit of GBDT was the largest. Within the threshold ranges of ~0.03-0.10 and 0.26-0.30, the net benefit of RF was the largest. Age was the most important predictor variable in the RF and GBDT models. Blood urea nitrogen, serum albumin, uric acid, body mass index (BMI), marital status, activities of daily living (ADL)/instrumental activities of daily living (IADL) and gender were crucial in predicting CKD in the elderly.

Conclusion

The ML model could successfully capture the linear and nonlinear relationships of risk factors for CKD in the elderly. The decision support system based on the predictive model in this research can help medical staff detect and intervene in the health of the elderly early.

A promising tool: triglyceride-glucose index to stratify the risk of cardiovascular events in chronic kidney disease

Lipid profile management is one of the crucial components to optimize outcomes in patients with chronic kidney disease (CKD). CKD is associated with poor cardiovascular outcomes due to both a direct cardiovascular impact of CKD and the presence of metabolic comorbidities. Low-density lipoprotein cholesterol is the main target of current lipid-lowering drugs. However, the derangement of lipid metabolism in CKD is more complex. The recently described triglyceride-glucose index (TyG) is associated with cardiovascular outcomes in the general population. In recent studies, the TyG was associated with CKD progression in CKD patients and with cardiovascular death in patients on peritoneal dialysis. Quiroga et al. now show that the TyG is associated with the occurrence of major cardiovascular events in individuals free from diabetes with non-dialysis-dependent CKD.

Untargeted Metabolomic Plasma Profiling of Emirati Dialysis Patients with Diabetes versus Non-Diabetic: A Pilot Study

Diabetic kidney disease (DKD) is a severe irreversible complication of diabetes mellitus that further disturbs glucose metabolism. Identifying metabolic changes in the blood may provide early insight into DKD pathogenesis. This study aims to determine blood biomarkers differentiating DKD from non-diabetic kidney disease in the Emirati population utilizing the LC-MS/MS platform. Blood samples were collected from hemodialysis subjects with and without diabetes to detect indicators of pathological changes using an untargeted metabolomics approach. Metabolic profiles were analyzed based on clinically confirmed diabetic status and current HbA1c values. Five differentially significant metabolites were identified based on the clinically confirmed diabetic status, including hydroxyprogesterone and 3,4-Dihydroxymandelic acid. Similarly, we identified seven metabolites with apparent differences between Dialysis Diabetic (DD) and Dialysis non-Diabetic (DND) groups, including isovalerylglycine based on HbA1c values. Likewise, the top three metabolic pathways, including Tyrosine metabolism, were identified following the clinically confirmed diabetic status. As a result, nine different metabolites were enriched in the identified metabolic pathways, such as 3,4-Dihydroxymandelic acid. As a result, eleven different metabolites were enriched, including Glycerol. This study provides an insight into blood metabolic changes related to DKD that may lead to more effective management strategies.

A comprehensive insight into the molecular and cellular mechanisms of the effects of Propolis on preserving renal function: a systematic review

BACKGROUND

The present systematic review is conducted, focusing on the existing evidence of Propolis's effects due to its various health benefits, mainly antioxidant and anti-inflammatory properties on preserving renal function.

METHODS

A systematic search of PubMed, Scopus, Embase, ProQuest, and Google Scholar was undertaken for relevant papers published from the start until January 2021.

RESULTS

This review revealed that Propolis affects fasting blood sugar (FBS), postprandial blood glucose, advanced glycation end products (AGEs) concentrations, malondialdehyde (MDA) levels, urinary concentrations of reactive oxygen metabolites (Tbars), total oxidant status (TOS), oxidative stress index (OSI), and 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation favorably. The findings on hemoglobin A1C (HbA1C), insulin, homeostasis model assessment of insulin resistance (HOMA-IR), β-cell function (HOMA-β), quantitative insulin sensitivity check index (QUICKI), and lipid profile were controversial. Moreover, a significant reduction in renal nuclear factor kappa B (NF-κB), serum immunoglobulins, renal ED-1+ cells, and urinary monocyte chemoattractant protein-1 (MCP-1) following Propolis supplementation has been reported, while the results on interleukin-6 (IL-6), tumor necrosis factor α (TNF-α), nitric oxide (NO), nitric oxide synthetase (NOS), and high sensitivity C-reactive protein (hs-CRP) were controversial. Furthermore, included studies showed its anti- proteinuria and kidney restoring effects.

CONCLUSION

In this review, both human and animal studies provide us evidences that Propolis could potentially improve the glycemic status, oxidative stress, renal tissue damage, and renal function. Further studies are needed to determine the underlying mechanisms.

Higher Serum Total Cholesterol to High-Density Lipoprotein Cholesterol Ratio Is Associated with Increased Mortality among Incident Peritoneal Dialysis Patients

This study evaluated the association of the serum total cholesterol to high-density lipoprotein cholesterol ratio (TC/HDL-C) with mortality in incident peritoneal dialysis (PD) patients. We performed a multi-center, prospective cohort study of 630 incident PD patients from 2008 to 2015 in Korea. Participants were stratified into quintiles according to baseline TC, HDL-C, LDL-C and TC/HDL-C. The association between mortality and each lipid profile was evaluated using multivariate Cox regression analysis. During a median follow-up period of 70.3 ± 25.2 months, 185 deaths were recorded. The highest TC/HDL-C group had the highest body mass index, percentage of diabetes and serum albumin level. Multivariate analysis demonstrated that the highest quintile of TC/HDL-C was associated with increased risk of all-cause mortality (hazard ratio 1.69, 95% confidence interval 1.04-2.76; p = 0.036), whereas TC, HDL-C and LDL-C were not associated with mortality. Linear regression analysis showed a positive correlation between TC/HDL-C and body mass index. Increased serum TC/HDL-C was an independent risk factor for mortality in the subgroup of old age, female, cardiovascular disease and low HDL-C. The single lipid marker of TC or HDL-C was not able to predict mortality in PD patients. However, increased serum TC/HDL-C was independently associated with all-cause mortality in PD patients.

Molecular Mapping of Neutral Lipids Using Silicon Nanopost Arrays and TIMS Imaging Mass Spectrometry

We demonstrate the utility of combining silicon nanopost arrays (NAPA) and trapped ion mobility imaging mass spectrometry (TIMS IMS) for high spatial resolution and specificity mapping of neutral lipid classes in tissue. Ionization of neutral lipid species such as triglycerides (TGs), cholestryl esters (CEs), and hexosylceramides (HexCers) from biological tissues has remained a challenge for imaging applications. NAPA, a matrix-free laser desorption ionization substrate, provides enhanced ionization efficiency for the above-mentioned neutral lipid species, providing complementary lipid coverage to matrix-assisted laser desorption ionization (MALDI). The combination of NAPA and TIMS IMS enables imaging of neutral lipid species at 20 μm spatial resolution while also increasing molecular coverage greater than 2-fold using gas-phase ion mobility separations. This is a significant improvement with respect to sensitivity, specificity, and spatial resolution compared to previously reported imaging studies using NAPA alone. Improved specificity for neutral lipid analysis using TIMS IMS was shown using rat kidney tissue to separate TGs, CEs, HexCers, and phospholipids into distinct ion mobility trendlines. Further, this technology allowed for the separation of isomeric species, including mobility resolved isomers of Cer(d42:2) (m/z 686.585) with distinct spatial localizations measured in rat kidney tissue section.

Sphingolipid imbalance and inflammatory effects induced by uremic toxins in heart and kidney cells are reversed by dihydroceramide desaturase 1 inhibition

Non-dialysable protein-bound uremic toxins (PBUTs) contribute to the development of cardiovascular disease (CVD) in chronic kidney disease (CKD) and vice versa. PBUTs have been shown to alter sphingolipid imbalance. Dihydroceramide desaturase 1 (Des1) is an important gatekeeper enzyme which controls the non-reversible conversion of sphingolipids, dihydroceramide, into ceramide. The present study assessed the effect of Des1 inhibition on PBUT-induced cardiac and renal effects in vitro, using a selective Des1 inhibitor (CIN038). Des1 inhibition attenuated hypertrophy in neonatal rat cardiac myocytes and collagen synthesis in neonatal rat cardiac fibroblasts and renal mesangial cells induced by the PBUTs, indoxyl sulfate and p-cresol sulfate. This is at least attributable to modulation of NF-κB signalling and reductions in β-MHC, Collagen I and TNF-α gene expression. Lipidomic analyses revealed Des1 inhibition restored C16-dihydroceramide levels reduced by indoxyl sulfate. In conclusion, PBUTs play a critical role in mediating sphingolipid imbalance and inflammatory responses in heart and kidney cells, and these effects were attenuated by Des1 inhibition. Therefore, sphingolipid modifying agents may have therapeutic potential for the treatment of CVD and CKD and warrant further investigation.

Dissecting Efficacy and Metabolic Characteristic Mechanism of Taxifolin on Renal Fibrosis by Multivariate Approach and Ultra-Performance Liquid Chromatography Coupled With Mass Spectrometry-Based Metabolomics Strategy

Taxifolin (TFN) is an important natural compound with antifibrotic activity; however, its pharmacological mechanism is not clear. In this study, our aim is to gain insight into the effects of TFN and its potential mechanisms in unilateral ureteral obstruction (UUO) animal model using metabolomics approach to identify the metabolic biomarkers and perturbed pathways. Serum metabolomics analysis by UPLC-Q-TOF/MS was carried out to discover the changes in the metabolic profile. It showed that TFN has a significant protective effect on UUO-induced renal fibrosis and a total of 32 potential biomarkers were identified and related to RF progression. Of note, 27 biomarkers were regulated by TFN treatment, which participate in eight metabolic pathways, including phenylalanine, tyrosine and tryptophan biosynthesis, and phenylalanine metabolism. It also showed that metabolomics was a promising strategy to better dissect metabolic characteristics and pharmacological mechanisms of natural compounds by multivariate approach and ultra-performance liquid chromatography coupled with mass spectrometry.

Plasma metabolites associated with chronic kidney disease and renal function in adults from the Baltimore Longitudinal Study of Aging

INTRODUCTION

Chronic kidney disease (CKD) is an important cause of disability and death, but its pathogenesis is poorly understood. Plasma metabolites can provide insights into underlying processes associated with CKD.

OBJECTIVES

To clarify the relationship of plasma metabolites with CKD and renal function in human.

METHODS

We used a targeted metabolomics approach to characterize the relationship of 450 plasma metabolites with CKD and estimated glomerular filtration rate (eGFR) in 616 adults, aged 38-94 years, who participated in the Baltimore Longitudinal Study of Aging.

RESULTS

There were 74 (12.0%) adults with CKD. Carnitine, acetylcarnitine, propionylcarnitine, butyrylcarnitine, trigonelline, trimethylamine N-oxide (TMAO), 1-methylhistidine, citrulline, homoarginine, homocysteine, sarcosine, symmetric dimethylarginine, aspartate, phenylalanine, taurodeoxycholic acid, 3-indolepropionic acid, phosphatidylcholines (PC).aa.C40:2, PC.aa.C40:3, PC.ae.C40:6, triglycerides (TG) 20:4/36:3, TG 20:4/36:4, and choline were associated with higher odds of CKD in multivariable analyses adjusting for potential confounders and using a false discovery rate (FDR) to address multiple testing. Six acylcarnitines, trigonelline, TMAO, 18 amino acids and biogenic amines, taurodeoxycholic acid, hexoses, cholesteryl esters 22:6, dehydroepiandrosterone sulfate, 3-indolepropionic acid, 2 PCs, 17 TGs, and choline were negatively associated with eGFR, and hippuric acid was positively associated with eGFR in multivariable analyses adjusting for potential confounders and using a FDR approach.

CONCLUSION

The metabolites associated with CKD and reduced eGFR suggest that several pathways, such as the urea cycle, the arginine-nitric oxide pathway, the polyamine pathway, and short chain acylcarnitine metabolism are altered in adults with CKD and impaired renal function.

Progress of research on dyslipidemia accompanied by nephrotic syndrome

Nephrotic syndrome is a relatively common clinical disease. Associated dyslipidemia is a risk factor for the occurrence and development of cardiovascular and renal diseases that might gradually develop into atherosclerosis, glomerulosclerosis or tubulointerstitial injury. It also confers an elevated risk of complications such as thromboembolism. If not properly controlled over the long term, dyslipidemia will become a key factor in a poor prognosis. Furthermore, dyslipidemia correlates with an increase in hepatic compensatory synthetic lipoprotein levels and a decrease in lipoprotein clearance, which can be sourced to the downregulation of hepatic and lipoprotein lipase activities in endothelial cells, muscle, and adipose tissue, and clinically characterized as hypertriglyceridemia or hypercholesterolemia. However, further investigations into the mechanism(s) of dyslipidemia are needed, with the resultant detailed perspectives and analyses substantially aiding the further development of treatment guidelines. Currently, statins represent the most popular type of pharmaceutical intervention because they lower hepatic cholesterol production and promote the absorption of low-density lipoprotein-cholesterol from the bloodstream, followed by second-line and other potential therapies to regulate the expression of specific receptors.

Remedial role of exercise training to deep-fried oil-induced metabolic and histological changes in Wistar rats

Exercise training is a well-known lifestyle to maintain good health. The present study was conducted to explore the effect of regular exercise training (for 15 min) on biochemical, physiological, and histological changes in fried oil intake (5 g/kg body weight, for 5 weeks) with or without raw oil supplementation. Liver disease and heart muscle injury were accounted for by significant (p < .05) increase in liver and heart biomarker enzymes in serum. Creatinine and urea level were also significantly increased in the fried oil-fed group as a sign of kidney injury. But all the biological markers including triglycerides, low-density lipoprotein cholesterol (LDL-C) was decreased significantly (p < .05) in the exercise-trained rat group. These metabolic changes were substantiated by the histological study of respective organs. Therefore, people should avoid repeatedly deep-fried oil consumption rather than fresh ones though regular exercise training has been found to resolve these metabolic abnormalities. PRACTICAL APPLICATIONS: Exercise training is a common practice to reduce the onset of some metabolic abnormalities for example cardiovascular disease, non-alcoholic fatty liver disease, chronic kidney disease, and also prevents various cell and tissue damages. Repeated frying of vegetable oil not only reduces its nutritional value but also produce free fatty acids and other toxic compounds. The present study revealed that repeatedly heated vegetable oil consumption causes injuries in the heart, liver, kidney, and small intestine by the oxidative products. As a result, the level of biomarkers of these responsive organs was found to be elevated. But regular exercise training ameliorated these detrimental effects. So, in terms of public health concern, regular exercise is one of the best ways to keep the body fit especially those who are consuming deep-fried oil.

Cardiorenal syndrome: Multi-organ dysfunction involving the heart, kidney and vasculature

Cardiorenal syndrome (CRS) is a multi-organ disease, encompassing heart, kidney and vascular system dysfunction. CRS is a worldwide problem, with high morbidity, mortality, and inflicts a significant burden on the health care system. The pathophysiology is complex, involving interactions between neurohormones, inflammatory processes, oxidative stress and metabolic derangements. Therapies remain inadequate, mainly comprising symptomatic care with minimal prospect of full recovery. Challenges include limiting the contradictory effects of multi-organ targeted drug prescriptions and continuous monitoring of volume overload. Novel strategies such as multi-organ transplantation and innovative dialysis modalities have been considered but lack evidence in the CRS context. The adjunct use of pharmaceuticals targeting alternative pathways showing positive results in preclinical models also warrants further validation in the clinic. In recent years, studies have identified the involvement of gut dysbiosis, uraemic toxin accumulation, sphingolipid imbalance and other unconventional contributors, which has encouraged a shift in the paradigm of CRS therapy.

Effects of Statins on Lipid Profile of Kidney Transplant Recipients: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

To assess the benefits of statins on lipid profile in kidney transplant recipients via a meta-analysis.

METHODS

We systematically identified peer-reviewed clinical trials, review articles, and treatment guidelines from PubMed, Embase, the Cochrane Library, Wanfang, Chinese National Knowledge Infrastructure (CNKI), SinoMed (CBM), and Chongqing VIP databases from inception to April 2019. In the analysis, only randomized controlled clinical trials performed in human were included.

RESULTS

Eight articles were included in the analysis, involving 335 kidney transplant recipients who received statins and 350 kidney transplant patients as the control group. Results revealed that statins improved the lipid profile of kidney transplant recipients. Specifically, statin therapy significantly reduced total cholesterol and low-density lipoprotein cholesterol. However, it had no effects on high-density lipoprotein cholesterol and triglyceride levels.

CONCLUSIONS

The present study provides valuable knowledge on the potential benefits of statins in kidney transplant recipients. This meta-analysis shows that statin therapy modifies the lipid profile in this patient population.

PNPLA3 rs738409 is associated with renal glomerular and tubular injury in NAFLD patients with persistently normal ALT levels

BACKGROUND & AIMS

Patatin-like phospholipase domain-containing protein 3 (PNPLA3) rs738409 polymorphism is associated with NAFLD severity and the PNPLA3 gene is expressed in the kidneys, but whether PNPLA3 rs738409 polymorphism is also associated with renal tubular injury (RTI) is uncertain. We assessed the effect of PNPLA3 genotypes on biomarkers of RTI and glomerular function in subjects with NAFLD who had either normal (nALT) or abnormal (abnALT) alanine aminotransaminase levels.

METHODS

Two hundred and seventeen patients with histologically proven NAFLD of which 75 had persistently nALT (below upper limit of normal for 3 months) were included. Multivariable regression analyses were undertaken to test associations between PNPLA3 genotype and biomarkers of kidney dysfunction.

RESULTS

The nALT patient group had higher urinary neutrophil gelatinase-associated lipocalin levels (u-NGAL, a biomarker of RTI) (P < .001), higher albuminuria (P = .039) and greater prevalence of chronic kidney disease (CKD; P = .046) than the abnALT group. The association between PNPLA3 GG genotype and risk of CKD and abnormal albuminuria remained significant after adjustment for kidney risk factors and severity of NAFLD histology, mostly in the nALT group. Similarly, PNPLA3 GG genotype was associated with higher u-NGAL levels in the nALT group, even after adjustment for the aforementioned risk factors and glomerular filtration-based markers (β-coefficient: 22.29, 95% CI: 0.99-43.60, P = .041).

CONCLUSION

Patients with NAFLD and persistently nALT, who carry the PNPLA3 rs738409 G allele, are at higher risk of early glomerular and tubular damage. We suggest PNPLA3 genotyping may help identify patients with NAFLD at higher risk of RTI.

A journey from microenvironment to macroenvironment: the role of metaflammation and epigenetic changes in cardiorenal disease

Chronic non-communicable diseases have become a pandemic public problem in the 21st century, causing enormous burden on the economy, health and quality of life of societies. The role of a chronic inflammatory state in the pathogenesis of chronic disease has been more comprehensively recognized by recent findings. The new paradigm ‘metaflammation’ focuses on metabolism-induced (high fat or fructose-based diet or excessive calorie intake) chronic inflammation. There is a close correlation between the increased incidence of chronic kidney disease (CKD) and chronic heart failure with both increased inflammatory marker levels and western-type diet. In this review we describe the concept of metaflammation, its role in the development of CKD and chronic heart disease, the molecular and signalling pathways involved and the therapeutic consequences.

Atherosclerosis in Chronic Kidney Disease: More, Less, or Just Different?

Patients with chronic kidney disease (CKD) are at an increased risk of premature mortality, mainly from cardiovascular causes. The association between CKD on hemodialysis and accelerated atherosclerosis was described >40 years ago. However, more recently, it has been suggested that the increase in atherosclerosis risk is actually observed in early CKD stages, remaining stable thereafter. In this regard, interventions targeting the pathogenesis of atherosclerosis, such as statins, successful in the general population, have failed to benefit patients with very advanced CKD. This raises the issue of the relative contribution of atherosclerosis versus other forms of cardiovascular injury such as arteriosclerosis or myocardial injury to the increased cardiovascular risk in CKD. In this review, the pathophysiogical contributors to atherosclerosis in CKD that are shared with the general population, or specific to CKD, are discussed. The NEFRONA study (Observatorio Nacional de Atherosclerosis en NEFrologia) prospectively assessed the prevalence and progression of subclinical atherosclerosis (plaque in vascular ultrasound), confirming an increased prevalence of atherosclerosis in patients with moderate CKD. However, the adjusted odds ratio for subclinical atherosclerosis increased with CKD stage, suggesting a contribution of CKD itself to subclinical atherosclerosis. Progression of atherosclerosis was closely related to CKD progression as well as to the baseline presence of atheroma plaque, and to higher phosphate, uric acid, and ferritin and lower 25(OH) vitamin D levels. These insights may help design future clinical trials of stratified personalized medicine targeting atherosclerosis in patients with CKD. Future primary prevention trials should enroll patients with evidence of subclinical atherosclerosis and should provide a comprehensive control of all known risk factors in addition to testing any additional intervention or placebo.

Proprotein convertase subtilisin/kexin type 9 in kidney disease

Chronic kidney disease (CKD) is associated with a substantially increased risk for the development of atherosclerotic cardiovascular (CV) disease. Accordingly, CV mortality is increased even in the earliest stages of CKD. In the general population and in CKD patients, high plasma levels of low-density lipoprotein cholesterol (LDL-C) are crucially involved in the initiation and progression of atherosclerotic vascular lesions. Lowering LDL-C by use of statins and/or ezetimibe represents the gold standard of lipid-lowering therapy, with a great body of evidence from several large clinical trials. Statin therapy reduces CV events in patients with normal and impaired kidney function alike, while the evidence for patients on maintenance haemodialysis is weaker. The inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) serine protease represents a novel lipid-lowering tool. Currently the monoclonal antibodies evolocumab and alirocumab are the approved PCSK9 inhibitors. Despite maximum-tolerated statin therapy, they efficiently further reduce LDL-C plasma levels without any major adverse effects. Moreover, in large clinical outcome trials, both antibodies have been proven to lower CV events. Notably, the LDL-lowering capacity was independent of baseline kidney function and also efficient in patients with moderate CKD. However, patients with severely impaired kidney function, that is, the population at the highest CV risk, have been excluded from those trials. The relevance of the LDL-independent effects of PCSK9 inhibitors, such as lowering lipoprotein(a) or ameliorating dyslipidaemia in patients with nephrotic syndrome, has to be determined. Therefore further specific studies assessing the effects and outcomes of PCSK9-inhibiting treatment in CKD patients are warranted.