Proteomic Correlates and Prognostic Significance of Kidney Injury in Heart Failure With Preserved Ejection Fraction.

BACKGROUND: Kidney disease is common in heart failure with preserved ejection fraction (HFpEF). However, the biologic correlates and prognostic significance of kidney injury (KI), in HFpEF, beyond the estimated glomerular filtration rate (eGFR), are unclear. METHODS AND RESULTS: Using baseline plasma samples from the TOPCAT (Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist) trial, we measured the following KI biomarkers: cystatin-C, fatty acid-binding protein-3, Beta-2 microglobulin, neutrophil gelatinase-associated lipocalin, and kidney-injury molecule-1. Factor analysis was used to extract the common variability underlying these biomarkers. We assessed the relationship between the KI-factor score and the risk of death or HF-related hospital admission in models adjusted for the Meta-Analysis Global Group in Chronic Heart Failure risk score and eGFR. We also assessed the relationship between the KI factor score and ~5000 plasma proteins, followed by pathway analysis. We validated our findings among HFpEF participants in the Penn Heart Failure Study. KI was associated with the risk of death or HF-related hospital admission independent of the Meta-Analysis Global Group in Chronic Heart Failure risk score and eGFR. Both the risk score and eGFR were no longer associated with death or HF-related hospital admission after adjusting for the KI factor score. KI was predominantly associated with proteins and biologic pathways related to complement activation, inflammation, fibrosis, and cholesterol homeostasis. KI was associated with 140 proteins, which reproduced across cohorts. Findings regarding biologic associations and the prognostic significance of KI were also reproduced in the validation cohort. CONCLUSIONS: KI is associated with adverse outcomes in HFpEF independent of baseline eGFR. Patients with HFpEF and KI exhibit a plasma proteomic signature indicative of complement activation, inflammation, fibrosis, and impaired cholesterol homeostasis.

Serum and urinary monocyte chemoattractant protein-1 as markers of inflammation and renal damage in dogs with naturally occurring leishmaniosis.

BACKGROUND: Renal disease in canine leishmaniosis is of great importance owing to increased risk of mortality. In human visceral leishmaniosis, monocyte chemoattractant protein-1 (MCP-1) has been used as a marker of renal damage and inflammation. The purpose of this study was first to determine the serum MCP-1 and urinary MCP-1-to-creatinine ratio (uMCP-1/Cr) in healthy dogs and dogs with leishmaniosis at diagnosis, and second to determine whether these markers can differentiate disease severity at diagnosis. METHODS: In total, 19 healthy seronegative dogs and 38 dogs with leishmaniosis were included in the study. Dogs with leishmaniosis were classified as LeishVet clinical staging and as International Renal Interest Society (IRIS) staging. Serum and urinary MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. A receiver operating characteristic (ROC) curve determined disease severity at diagnosis between two LeishVet groups (Stage II versus stage III and IV). RESULTS: Dogs in Leishvet stages IIb, III, and IV had a median serum MCP-1 and uMCP-1/Cr concentration higher than healthy dogs (P < 0.0001). No statistical differences were found in serum MCP-1 and uMCP-1/Cr between dogs in LeishVet stage IIa and healthy dogs. The dogs in LeishVet stage IV had significantly higher serum MCP-1 and uMCP-1/Cr compared with the dogs in LeishVet stage IIa (P < 0.0001). Serum MCP-1 and uMCP-1 were significantly higher in dogs in IRIS stage I and II + III + IV compared with healthy dogs. Dogs stage II + III + IV of IRIS had a significantly higher serum MCP-1 compared with dogs in IRIS stage I (P < 0.0001). The area under the ROC curve for serum MCP-1 was 0.78 [95% confidence interval (CI) 0.64-0.93] and for uMCP-1/Cr it was 0.86 (95% CI, 0.74-0.99). The optimal cutoff value for serum MCP-1 and uMCP-1/Cr was 336.85 pg/ml (sensitivity of 79% and specificity of 68%) and 6.89 × 10-7 (sensitivity of 84% and specificity of 79%), respectively. CONCLUSIONS: Serum MCP-1 and uMCP-1/Cr are increased in dogs with leishmaniosis compared with healthy dogs, suggesting the presence of inflammation and renal injury. Serum MCP-1 and uMCP-1/Cr were more elevated in the advanced stages of the disease compared with the moderate stages and, therefore, can be markers of the severity of the disease process.

Long-term ambient air pollution exposure and renal function and biomarkers of renal disease.

BACKGROUND: Despite accumulating evidence of an association between air pollution and renal disease, studies on the association between long-term exposure to air pollution and renal function are still contradictory. This study aimed to investigate this association in a large population with relatively low exposure and with improved estimation of renal function as well as renal injury biomarkers. METHODS: We performed a cross-sectional analysis in the middle-aged general population participating in the Swedish CardioPulmonary bioImaging Study (SCAPIS; n = 30 154). Individual 10-year exposure to total and locally emitted fine particulate matter (PM2.5), inhalable particulate matter (PM10), and nitrogen oxides (NOx) were modelled using high-resolution dispersion models. Linear regression models were used to estimate associations between exposures and estimated glomerular filtration rate (eGFR, combined creatinine and cystatin C) and serum levels of renal injury biomarkers (KIM-1, MCP-1, IL-6, IL-18, MMP-2, MMP-7, MMP-9, FGF-23, and uric acid), with consideration of potential confounders. RESULTS: Median long-term PM2.5 exposure was 6.2 µg/m3. Almost all participants had a normal renal function and median eGFR was 99.2 mL/min/1.73 m2. PM2.5 exposure was associated with 1.3% (95% CI 0.6, 2.0) higher eGFR per 2.03 µg/m3 (interquartile range, IQR). PM2.5 exposure was also associated with elevated serum matrix metalloproteinase 2 (MMP-2) concentration, with 7.2% (95% CI 1.9, 12.8) higher MMP-2 per 2.03 µg/m3. There was a tendency towards an association between PM10 and higher levels of uric acid, but no associations were found with the other biomarkers. Associations with other air pollutants were null or inconsistent. CONCLUSION: In this large general population sample at low exposure levels, we found a surprising association between PM2.5 exposure and a higher renal filtration. It seems unlikely that particle function would improve renal function. However, increased filtration is an early sign of renal injury and may be related to the relatively healthy population at comparatively low exposure levels. Furthermore, PM2.5 exposure was associated with higher serum concentrations of MMP-2, an early indicator of renal and cardiovascular pathology.

Association between the triglyceride glucose-body mass index and future cardiovascular disease risk in a population with Cardiovascular-Kidney-Metabolic syndrome stage 0-3: a nationwide prospective cohort study.

BACKGROUND: The American Heart Association (AHA) has recently introduced the concept of Cardiovascular-Kidney-Metabolic (CKM) syndrome, which is the result of an increasing emphasis on the interplay of metabolic, renal and cardiovascular diseases (CVD). Furthermore, there is substantial evidence of a correlation between the triglyceride glucose-body mass index (TyG-BMI ) and CVD as an assessment of insulin resistance (IR). However, it remains unknown whether this correlation exists in population with CKM syndrome. METHODS: All data for this study were obtained from the China Health and Retirement Longitudinal Study (CHARLS). The exposure was the participants' TyG-BMI at baseline, which was calculated using a combination of triglycerides (TG), fasting blood glucose (FBG) and body mass index (BMI). The primary outcome was CVD, which were determined by the use of a standardised questionnaire during follow-up. To examine the relationship between TyG-BMI and CVD incidence in population with CKM syndrome, both Cox regression analyses and restricted cubic spline (RCS) regression analyses were performed. RESULTS: A total of 7376 participants were included in the final analysis. Of these, 1139, 1515, 1839, and 2883 were in CKM syndrome stages 0, 1, 2, and 3, respectively, at baseline. The gender distribution was 52.62% female, and the mean age was 59.17 ± 9.28 (years). The results of the fully adjusted COX regression analyses indicated that there was a 6.5% increase in the risk of developing CVD for each 10-unit increase in TyG-BMI,95% confidence interval (CI):1.041-1.090. The RCS regression analyses demonstrated a positive linear association between TyG-BMI and the incidence of CVD in the CKM syndrome population (P for overall < 0.001, P for nonlinear = 0.355). CONCLUSIONS: This cohort study demonstrated a positive linear association between TyG-BMI index and increased CVD incidence in a population with CKM syndrome stage 0-3. This finding suggests that enhanced assessment of TyG-BMI index may provide a more convenient and effective tool for individuals at risk for CVD in CKM syndrome stage 0-3.

Risk assessment for perfluorooctanoic acid (PFOA) in air, blood serum and water: mortality from liver and kidney disease.

BACKGROUND: Cancer and non-cancer associations have been observed with PFAS (perfluoroalkyl and polyfluoroalkyl) substances in the general population, in populations from locally contaminated environments and in exposed workers. METHODS: A quantitative risk assessment on the PFAS substance perfluorooctanoic acid (PFOA) was conducted for six outcomes using two occupational mortality studies that reported sufficient data to estimate exposure-relationships in relation to serum PFOA levels. Excess lifetime mortality risks were calculated using a life table procedure that applies an exposure response to time-dependent PFOA serum levels for a surviving hypothetical population from ages 20 to 85. Both occupational and general population exposures were described as serum levels, and as air and drinking water concentrations. RESULTS: The estimated occupational inhalation concentrations conferring the benchmark one-per-thousand lifetime risk were 0.21 µg/m3 for chronic kidney disease, 1.0 µg/m3 for kidney cancer and (from the two studies) 0.67 and 1.97 µg/m3 for chronic liver disease. Specific excess lifetime risks estimated in the general population at current PFOA serum levels (~ 1 ng/mL) range 1.5-32 per 100 000 which corresponds to drinking water concentrations of less than 10 ppt. CONCLUSION: Over eight outcome risk estimates, the serum PFOA concentrations conferring 1/1000 occupational lifetime risk ranged 44 to 416 ng/mL corresponding to air concentrations ranging 0.21 to 1.99 µg/m3. The analyses provide a preliminary PFOA quantitative risk assessment for liver and kidney disease mortality which, together with reported assessments for several other end-points, would inform policy on PFAS.

Mendelian Randomization Analysis of Systemic Iron Status and Risk of Different Types of Kidney Disease.

With rapid increases in incidence, diverse subtypes, and complicated etiologies, kidney disease remains a global public health problem. Iron, as an essential trace element, has pleiotropic effects on renal function and the progression of kidney diseases. A two-sample Mendelian randomization (MR) analysis was implemented to determine the potential causal effects between systemic iron status on different kidney diseases. Systemic iron status was represented by four iron-related biomarkers: serum iron, ferritin, transferrin saturation (TfSat), and total iron binding capacity (TIBC). For systemic iron status, 163,511, 246,139, 131,471, and 135,430 individuals were included in the genome-wide association study (GWAS) of serum iron, ferritin, TfSat, and TIBC, respectively. For kidney diseases, 653,143 individuals (15,658 cases and 637,485 controls), 657,076 individuals (8160 cases and 648,916 controls), and 659,320 individuals (10,404 cases and 648,916 controls) were included for immunoglobulin A nephropathy (IgAN), acute kidney disease (AKD), and chronic kidney disease (CKD), respectively. Our MR results showed that increased serum iron [odds ratio (OR): 1.10; 95% confidence interval (95% CI): 1.04, 1.16; p < 0.0042], ferritin (OR: 1.30; 95% CI: 1.14, 1.48; p < 0.0042), and TfSat (OR: 1.07; 95% CI: 1.04, 1.11; p < 0.0042)] and decreased TIBC (OR: 0.92; 95% CI: 0.88, 0.97; p < 0.0042) were associated with elevated IgAN risk. However, no significant associations were found between systemic iron status and AKD or CKD. In our MR study, the genetic evidence supports elevated systemic iron status as a causal effect on IgAN, which suggests a potential protective effect of iron chelation on IgAN patients.

Investigation of symmetric dimethylarginine as a serologic marker for kidney function in striped skunks (Mephitis mephitis).

IMPORTANCE: Kidney disease is prevalent among veterinary species, including zoo animals; however, investigations into this condition in striped skunks (Mephitis mephitis) are scarce. Diagnostic tools for kidney diseases in this species also remain limited. OBJECTIVE: This study aimed to assess the utility of symmetric dimethylarginine as a biomarker for kidney disease in captive striped skunks in Korea. METHODS: This retrospective study analysed 11 striped skunks housed at the Everland Zoo between 2017 and 2021. Blood samples were collected during health checks. Kidney function was assessed through blood analysis and diagnostic ultrasound, with necropsies conducted on deceased animals. Symmetric dimethylarginine levels were measured in 27 plasma samples collected from 11 skunks. RESULTS: Over the study period, seven skunks were diagnosed with kidney disease. Analysis of 27 blood samples revealed a concurrent increase in SDMA levels with concentrations of blood urea nitrogen and blood creatinine. In 3 of the 7 skunks with kidney disease, symmetric dimethylarginine exceeded 14 µg/dL prior to the elevation of blood urea nitrogen and blood creatinine above the upper reference limit. CONCLUSIONS AND RELEVANCE: To our knowledge, this is the first study investigating symmetric dimethylarginine in captive striped skunks in Korea. Our findings suggest that symmetric dimethylarginine may serve as an early and consistent biomarker for renal dysfunction in striped skunks. Further studies with larger clinical sample size from striped skunks are needed to validate the clinical utility of blood symmetric dimethylarginine concentration.

[Estimating glomerular filtration rate]. / Het schatten van de glomerulaire filtratiesnelheid.

Almost all laboratories in The Netherlands report an estimated glomerular filtration rate (eGFR) whenever a value for plasma creatinine is requested. This formula is based on gender and age, besides the plasma creatinine concentration, and sometimes also a correction for race is applied. While this GFR reporting improved the recognition of chronic kidney disease, the formulas used have intrinsic limitations. Moreover, recently a novel formula that obviates the need for a correction factor for race has been proposed. In this article the strengths and weaknesses of plasma creatinine and formulas based on that are discussed, following ten frequently asked questions.

The potential Role of CYP2D6*10(c.100 C>T) Gene Polymorphism in Kidney Injury of Patients with Hypertension Complicated with Non-Elevated Cystatin C.

This study aims to investigate the potential role of CYP2D6*10 (c.100 C>T) gene polymorphism in renal function injury among hypertensive patients without elevated cystatin C. A cohort of hypertensive patients without elevated cystatin C was enrolled between 2021 and 2024 in the Fourth Affiliated Hospital of Soochow University, and their peripheral venous blood was used for total RNA extraction and CYP2D6*10 genotype analysis. Based on kidney injury status, patients were categorized into two groups, hypertensive patients with kidney injury (n = 94) and those without (n = 893). General characteristics such as age, gender and hyperlipemia were compared between the two groups. Multiple genotype models were investigated between the two groups, including allele models, dominant models, recessive models, co-dominant models, and super-dominant models. The results revealed that in the co-dominant gene model (CC vs. CT vs. TT), the risk of hypertension combined with renal injury was lower with the CT genotype compared to the CC genotype (Odds Ratio (OR) = 0.55, 95% Confidence Interval (CI) = 0.32-0.93, p = 0.02). In the overdominance model (CC + TT vs. CT), the risk of hypertension and renal injury in CC and CT genotypes was 0.42 times lower than that in the CT genotype (OR = 0.42, 95% CI = 0.27-0.64, p < 0.001). This study proposes CYP2D610 gene polymorphism as a potential predictor of renal function injury in hypertensive patients with normal cystatin C levels.

TYG Index as a Novel Predictor of Clinical Outcomes in Advanced Chronic Heart Failure with Renal Dysfunction Patients.

Background: The triglyceride-glucose (TYG) index is a novel and reliable marker reflecting insulin resistance. Its predictive ability for cardiovascular disease onset and prognosis has been confirmed. However, for advanced chronic heart failure (acHF) patients, the prognostic value of TYG is challenged due to the often accompanying renal dysfunction (RD). Therefore, this study focuses on patients with aHF accompanied by RD to investigate the predictive value of the TYG index for their prognosis. Methods and Results: 717 acHF with RD patients were included. The acHF diagnosis was based on the 2021 ESC criteria for acHF. RD was defined as the eGFR < 90 mL/(min/1.73 m2). Patients were divided into two groups based on their TYG index values. The primary endpoint was major adverse cardiovascular events (MACEs), and the secondary endpoints is all-cause mortality (ACM). The follow-up duration was 21.58 (17.98-25.39) months. The optimal cutoff values for predicting MACEs and ACM were determined using ROC curves. Hazard factors for MACEs and ACM were revealed through univariate and multivariate COX regression analyses. According to the univariate COX regression analysis, high TyG index was identified as a risk factor for MACEs (hazard ratio = 5.198; 95% confidence interval [CI], 3.702-7.298; P < 0.001) and ACM (hazard ratio = 4.461; 95% CI, 2.962-6.718; P < 0.001). The multivariate COX regression analysis showed that patients in the high TyG group experienced 440.2% MACEs risk increase (95% CI, 3.771-7.739; P < 0.001) and 406.2% ACM risk increase (95% CI, 3.268-7.839; P < 0.001). Kaplan-Meier survival analysis revealed that patients with high TyG index levels had an elevated risk of experiencing MACEs and ACM within 30 months. Conclusion: This study found that patients with high TYG index had an increased risk of MACEs and ACM, and the TYG index can serve as an independent predictor for prognosis.

Effect of Statins on Serum Levels of TNF-alpha and Interleukin-6 in Patients with Kidney Disease: A Meta-analysis of Randomized Clinical Trials.

BACKGROUND AND OBJECTIVES: Some clinical trials have indicated the beneficial effects of statins in patients with kidney disease, while others have reported no positive effect of statins in these patients. We conducted this meta-analysis to identify the effects of statins on serum levels of interleukin-6 (IL-6) and Tumor Necrosis Factor Alpha (TNF-α) in patients with kidney disease. DESIGNS AND METHODS: A systematic literature search was performed using PubMed, Scopus, and Web of Science databases to identify all studies published from inception to August, 2022. The major outcome variable was the Weighted Mean Difference (WMD). Eligible studies were stratified based on target population, intervention duration, dosage and type of statins, and solubility of statins. RESULTS: Meta-analysis performed on seven publications (8 studies), including 213 patients with kidney disease and 188 control individuals, indicated that the concentration of IL-6 was marginally decreased in patients with kidney disease following statin therapy disease (WMD = -1.15 pg/mL; 95% CI = -2.33 to 0.04, P = 0.05, I2 = 68.5%). The findings of subgroup analysis based on the dosage of statins showed that neither highintensity nor moderate/low-intensity statin treatment could significantly influence the serum level of IL-6. Lipophilic statins were more effective than hydrophilic statins, and they marginally decreased the levels of IL-6 (WMD = -1.21 pg/mL; 95% CI = -2.43 to 0, P = 0.05, I2 = 55.7%). Meta-analysis of four publications (five studies) with 157 patients with kidney disease and 132 control subjects showed that statins reduced the serum levels of TNF-α in patients with kidney disease when compared with control individuals (WMD= -2.66 pg/mL; 95% CI = -4.26 to -1.06, P < 0.001, I2 = 63%). CONCLUSION: Statins only marginally decreased the concentration of IL-6 in patients with kidney disease, but neither high-intensity nor moderate/low-intensity statin treatment could significantly influence the level of IL-6. However, statins reduced serum levels of TNF-α in patients with kidney disease.

A Systematic Literature Review on the Use of Dried Biofluid Microsampling in Patients With Kidney Disease.

BACKGROUND: Kidney disease is fairly unique due to the lack of symptoms associated with disease activity, and it is therefore dependent on biological monitoring. Dried biofluids, particularly dried capillary blood spots, are an accessible, easy-to-use technology that have seen increased utility in basic science research over the past decade. However, their use is yet to reach the kidney patient population clinically or in large-scale discovery science initiatives. The aim of this study was to systematically evaluate the existing literature surrounding the use of dried biofluids in kidney research. METHODS: A systematic literature review was conducted using three search engines and a predefined search term strategy. Results were summarised according to the collection method, type of biofluid, application to kidney disease, cost, sample stability and patient acceptability. RESULTS: In total, 404 studies were identified and 67 were eligible. In total, 34,739 patients were recruited to these studies with a skew towards male participants (> 73%). The majority of samples were blood, which was used either for monitoring anti-rejection immunosuppressive drug concentrations or for kidney function. Dried biofluids offered significant cost savings to the patient and healthcare service. The majority of patients preferred home microsampling when compared to conventional monitoring. CONCLUSION: There is an unmet need in bringing dried microsampling technology to advance kidney disease despite its advantages. This technology provides an opportunity to upscale patient recruitment and longitudinal sampling, enhance vein preservation and overcome participation bias in research.

Blood-urea-nitrogen-to-serum-albumin ratio in predicting the value of patients with contrast-induced nephropathy for coronary heart disease.

BACKGROUND: The blood-urea-nitrogen (BUN)-to-serum-albumin (ALB) ratio (BAR) has been identified as a novel indicator of both inflammatory and nutritional status, exhibiting a correlation with adverse cardiovascular outcomes. This study aims to investigate the potential predictive value of BAR levels at admission for the development of CIN in patients undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI). METHODS: Retrospective data were collected from patients who were admitted and underwent CAG or PCI between January 2018 and December 2022 at the Cardiac Medical Center of Union Hospital of Fujian Medical University, and the patients were divided into CIN and non-CIN groups. The BAR was computed by dividing the BUN count by the ALB count. Using multiple variable logistic regression, risk variables associated with the development of CIN were found. RESULTS: A total of 156 patients developed CIN (7.78%). The development of CIN was predicted by a BAR ratio > 4.340 with a sensitivity of 84.0% and a specificity of 70.2%, according to receiver operating characteristic (ROC) analysis. BAR, female gender, diuretic use, and statin medication use were found to be independent predictors of CIN using multifactorial analysis. CONCLUSIONS: When patients are receiving CAG/PCI, BAR is a simple-to-use marker that can be used independently to predict the presence of CIN.

Serum soluble LYVE1 is a promising non-invasive biomarker of renal fibrosis: a population-based retrospective cross-sectional study.

Diagnosis of renal fibrosis can only be verified by kidney biopsy, but biomarkers for non-invasive evaluation remain unsatisfactory. Patients with fibrosis often have abnormalities of the lymphatic vascular system and associated immune function. We describe here a lymphatic marker as a candidate biomarker for fibrosis. After assessing and grading the fibrosis scores, testing serum soluble lymphatic vessel endothelial hyaluronan receptor1 (sLYVE1) level, and collecting clinical information, the association between sLYVE1 and renal fibrosis was analyzed. Logistic regression analysis was used to screen variables. Diagnosis models with or without sLYVE1 were built, and nomograms were plotted. Calibration curve, C-index, and DCA were performed to assess the models. A total of 298 patients were enrolled in the study, of which 199 were included in the training cohort and 99 patients in the validation cohort. Serum sLYVE1 levels markedly elevated with increasing fibrosis grade (p<0.05). ROC analysis of sLYVE1 showed an AUC of 0.791 and 0.846 with optimal cut-off value of 405.25 ng/mL and 498.55 ng/mL for the prediction of moderate-to-severe renal fibrosis (MSF) and severe renal fibrosis (SF), respectively. The diagnostic nomogram model without sLYVE1 (model 1) included traditional clinical determinants (C-index: 0.658 for MSF; 0.603 for SF). A combination of model 1 and sLYVE1 (model 2) improved predictive performance (C-index: 0.847 for MSF; 0.856 for SF). Calibration curve and DCA demonstrated a better consistency accuracy and clinical benefit of model 2 than model 1. Serum sLYVE1 may be identified as a potential biomarker of renal fibrosis. Models incorporating sLYVE1 may be beneficial for a more accurate non-invasive diagnosis of renal fibrosis.

Association Between Serum GDF15 Concentration and Total Mortality in Community-Dwelling Japanese Older Populations: The Involvement of Renal Dysfunction.

BACKGROUND: Serum growth differentiation factor 15 (GDF15) is associated with age-related adverse outcomes. However, renal function has not been thoroughly evaluated in studies addressing the association between GDF15 and mortality. We aimed to clarify whether GDF15 is associated with total mortality after carefully controlling renal function markers. METHODS: We divided 1 801 community-dwelling Japanese older adults into quartiles according to their serum GDF15 concentrations. The correlation of GDF15 with renal function and inflammation markers was assessed by calculating Spearman correlation coefficients. Cumulative survival rates of the quartiles were estimated. In a Cox regression analysis adjusted for confounders, the association between GDF15 and mortality was evaluated. The discriminative capacity of GDF15 for the prediction of mortality was assessed with receiver-operating characteristic analysis. RESULTS: GDF15 was correlated with cystatin C (r = 0.394), ß2-microglobulin (r = 0.382), C-reactive protein (r = 0.124), and interleukin-6 (r = 0.166). The highest GDF15 quartile showed poor survival compared to the others. Older adults with higher GDF15 were associated with an increased mortality risk, independent of demographics and clinically relevant variables (hazard ratio [95% confidence interval]: 1.98 [1.09-3.59]). This significant association disappeared when additionally adjusted for cystatin C (1.65 [0.89-3.05]) or ß2-microglobulin (1.69 [0.91-3.12]). The ability to predict mortality was approximately comparable between GDF15 (area under the curve: 0.667), cystatin C (0.691), and ß2-microglobulin (0.715). CONCLUSIONS: Serum GDF15 is associated with total mortality in older Japanese after adjustment for major confounders. The increased mortality risk in older adults with higher GDF15 may be partly attributed to decreased renal function.

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 ß = 1.1 (95% CI [0.411-1.788]; p = 0.002). Similarly, total cholesterol (TC) showed a significant causal effect on eGFR ß = 1.619 (95% CI [0.412-2.826]; p = 0.009). However, the IVW estimate showed that genetically predicted HDL-C ß = -0.164, (95% CI = [-1.329 to 1.00]; p = 0.782), and TG ß = -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 ß = 1.228 (CI = [0.477-1.979]; p = 0.001). A significant causal effect of Triglycerides (TG) on eGFR in the MVIVW analysis ß = -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 (ß = -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).

Effect of Severe Renal Dysfunction on the Plasma Levels of DNA-Reactive Platinum after Oxaliplatin Administration.

Higher amounts of circulating ultrafilterable platinum (fPt) are found in patients with renal dysfunction receiving a constant dose of oxaliplatin. However, the increased systemic fPt levels do not increase oxaliplatin-induced toxicities. We hypothesized that renal dysfunction has minimal effect on the elimination rate of reactive fPt, and that the DNA-binding capacity is one of the properties of reactive Pt species. This study aimed to quantify DNA-reactive fPt in plasma and to evaluate the impact of severe renal dysfunction on its pharmacokinetics. The pharmacokinetics of oxaliplatin was assessed in rats with bilateral nephrectomy (BNx) and in a hemodialysis patient who received mFOLFOX7 therapy for advanced metastatic gastric cancer. The platinum concentrations were determined using inductively coupled plasma-mass spectrometry. The amount of DNA-reactive fPt in the plasma was evaluated by the reaction between plasma and calf thymus DNA. Compared to the sham group in rats, the BNx group had significantly higher plasma total fPt concentrations at 24 h after drug administration. However, there was no significant difference in the plasma levels of DNA-reactive fPt between the two groups. In a hemodialysis patient, the plasma levels of total fPt decreased to 35.9 and 7.3% at 2 and 14 d after treatment, respectively. The plasma level of DNA-reactive fPt also decreased to 1.9 and 0.6%, respectively, on these days. This study showed that severe renal dysfunction has a limited effect on the plasma levels of DNA-reactive fPt after oxaliplatin administration.