Assessing kidney function--measured and estimated glomerular filtration rate

Reference standard analysis of multiple new and old plasma clearance models and renal clearance with special attention to measurement of reduced glomerular filtration rate

Nine models were evaluated as candidate glomerular filtration rate (GFR) reference standards in three datasets using [51Cr(EDTA)]- or [169Yb(DTPA)]2- anions in 98 studies. Noncompartmental methods formed an upper limit for estimating mass excreted and voluntary urine collection formed a lower limit. For current models and methods, reduced GFR in adults resulted in inflated clearance estimates. Two different logarithmic models with exponential tails were created and may have underestimated reduced clearance. The logarithmic formulae can be used with only two plasma samples, and fit 13 multiple time-samples from 5 min to 24 h with an 8% standard deviation of residuals compared to 20% error for monoexponentials. For shorter times (4 or 5 h) the fit errors decreased but the ratio of errors remained at circa 2.5 times lesser for the logarithmic versus monoexponential models. Adaptively regularised gamma variate, Tk-GV, models that are well documented, but not in common use, were largely contained within the reference extreme values, were unbiased for different levels of clearance and were the only models to be uncorrelated to volume of distribution from mean residence time divided by weight. Using Tk-GV as a candidate reference standard, potentially better methods for routine clinical usage were discussed. Prospective clinical testing, and metabolic scaling of decreased renal function is advised for potential changes to patient triage.

Exploration of Metabolomic Markers Associated With Declining Kidney Function in People With Type 2 Diabetes Mellitus

Background

Metabolomics, the study of small molecules in biological systems, can provide valuable insights into kidney dysfunction in people with type 2 diabetes mellitus (T2DM), but prospective studies are scarce. We investigated the association between metabolites and kidney function decline in people with T2DM.

Methods

The Edinburgh Type 2 Diabetes Study, a population-based cohort of 1066 men and women aged 60 to 75 years with T2DM. We measured 149 serum metabolites at baseline and investigated individual associations with baseline estimated glomerular filtration rate (eGFR), incident chronic kidney disease [CKD; eGFR <60 mL/min/(1.73 m)2], and decliner status (5% eGFR decline per year).

Results

At baseline, mean eGFR was 77.5 mL/min/(1.73 m)2 (n = 1058), and 216 individuals had evidence of CKD. Of those without CKD, 155 developed CKD over a median 7-year follow-up. Eighty-eight metabolites were significantly associated with baseline eGFR (β range -4.08 to 3.92; PFDR < 0.001). Very low density lipoproteins, triglycerides, amino acids (AAs), glycoprotein acetyls, and fatty acids showed inverse associations, while cholesterol and phospholipids in high-density lipoproteins exhibited positive associations. AA isoleucine, apolipoprotein A1, and total cholines were not only associated with baseline kidney measures (PFDR < 0.05) but also showed stable, nominally significant association with incident CKD and decline.

Conclusion

Our study revealed widespread changes within the metabolomic profile of CKD, particularly in lipoproteins and their lipid compounds. We identified a smaller number of individual metabolites that are specifically associated with kidney function decline. Replication studies are needed to confirm the longitudinal findings and explore if metabolic signals at baseline can predict kidney decline.

Obesity, Hyperfiltration, and Early Kidney Damage: A New Formula for the Estimation of Creatinine Clearance

CONTEXT

Glomerular hyperfiltration may represent a direct pathogenetic link between obesity and kidney disease. The most widely used methods to estimate creatine clearance such as Cockroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) have not been validated in subjects with obesity.

OBJECTIVE

The performance of prediction formulas was compared with measured creatinine clearance (mCrCl) in subjects with obesity.

METHODS

The study population included 342 patients with obesity (mean BMI 47.6 kg/m2) without primary kidney disease. A urine collection was performed over 24 hours for measurement of CrCl.

RESULTS

mCrCl increased with body weight. The CG formula showed an overestimation at high CrCl, whereas an underestimation resulted from CKD-EPI and MDRD. To improve the accuracy of estimated CrCl (eCrCl), a new CG-based formula was developed:53+0.7×(140-Age)×Weight/(96xSCr)×(0.85iffemale)A cut-off point for BMI of 32 kg/m2 was identified, at which the new formula may be applied to improve eCrCl.

CONCLUSION

In patients with obesity the glomerular filtration rate increases with body weight, and it is associated with the presence of albuminuria, suggesting an early kidney injury. We propose a novel formula that improves the accuracy of eCrCl to avoid missed diagnoses of hyperfiltration in patients with obesity.

A Brief Review of Diagnostic Techniques and Clinical Management in Chronic Kidney Disease

Given its increasing incidence and detrimental effects on life expectancy and quality of life, chronic kidney disease (CKD) is a significant worldwide health concern. This review article provides a complete summary of current information on the diagnosis and management of CKD, focusing on recent advances and innovative approaches. The article discusses the most current findings on CKD risk assessment, emphasizing the need for early diagnosis utilizing better biomarkers and predictive models. A rigorous examination of diagnostic tools such as albumin-to-creatinine ratio (ACR) in urine and glomerular filtration rate (GFR) highlights their importance in determining CKD phases and etiologies. In terms of therapy, the study explores evidence-based techniques to reduce the development of CKD, such as enhanced blood pressure control, glycemic management in diabetic patients, dietary changes, and renin-angiotensin-aldosterone system (RAAS) blocking. Novel therapeutic approaches, including antifibrotic and precision medicine, are evaluated regarding their potential to revolutionize CKD treatment. The study also underlines the need for multidisciplinary therapy and patient education to achieve the best possible CKD patient outcomes. It also highlights the financial and social effects of CKD, highlighting the importance of early treatment to lower medical expenses and enhance the patient's standard of living. Finally, this review article provides a comprehensive update on CKD diagnosis and treatment, highlighting present successes alongside future potential. It is a valuable resource for healthcare professionals, academics, and policymakers who want to improve CKD treatment methods and patient outcomes.

Diagnostic challenges of diabetic kidney disease

Diabetic kidney disease (DKD) is one of the most common microvascular complications of both type 1 and type 2 diabetes and the most common cause of the end-stage renal disease (ESRD). It has been evidenced that targeted interventions at an early stage of DKD can efficiently prevent or delay the progression of kidney failure and improve patient outcomes. Therefore, regular screening for DKD has become one of the fundamental principles of diabetes care. Long-established biomarkers such as serum-creatinine-based estimates of glomerular filtration rate and albuminuria are currently the cornerstone of diagnosis and risk stratification in routine clinical practice. However, their immanent biological limitations and analytical variations may influence the clinical interpretation of the results. Recently proposed new predictive equations without the variable of race, together with the evidence on better accuracy of combined serum creatinine and cystatin C equations, and both race- and sex-free cystatin C-based equation, have enabled an improvement in the detection of DKD, but also require the harmonization of the recommended laboratory tests, wider availability of cystatin C testing and specific approach in various populations. Considering the complex pathophysiology of DKD, particularly in type 2 diabetes, a panel of biomarkers is needed to classify patients in terms of the rate of disease progression and/or response to specific interventions. With a personalized approach to diagnosis and treatment, in the future, it will be possible to respond to DKD better and enable improved outcomes for numerous patients worldwide.

Short and Long-Term Prognostic Significance of Galectin-3 in Patients with ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

This study evaluated the short and long-term prognostic value of galectin-3 in patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI). Patients (n = 143) were admitted with STEMI and followed up for 2 years. The study population was divided into high and low galectin-3 groups based on the admission median value of serum galectin-3. Primary clinical outcomes consisted of cardiovascular (CV) mortality, non-fatal reinfarction, stroke, and target vessel revascularization (TVR). CV events were recorded in hospital and at 1 and 2 years. The primary clinical outcomes (in-hospital, 1 year and 2 year) were significantly higher in the high galectin-3 group. (P = .008, P = .004, P = .002, respectively). High galectin-3 levels were also associated with heart failure development and re-hospitalization at both 1 year (P = .029, P = .009, respectively) and 2 years (P = .019, P = .036, respectively). According to Cox multivariate analysis, left ventricular ejection fraction (LVEF) was an independent predictor of 2-year cardiovascular mortality (P = .009), whereas galectin-3 was not (P = .291). Although high galectin-3 levels were not independent predictors of long-term CV mortality in patients with acute STEMI who underwent primary PCI, it was associated with short-term and long-term development of adverse CV events, heart failure, and re-hospitalization.

Underweight status and development of end-stage kidney disease: A nationwide population-based study

BACKGROUND

Underweight status increases the risk of cardiovascular disease and mortality in the general population. However, whether underweight status is associated with an increased risk of developing end-stage kidney disease is unknown.

METHODS

A total of 9 845 420 participants aged ≥20 years who underwent health checkups were identified from the Korean National Health Insurance Service database and analysed. Individuals with underweight (body mass index [BMI] < 18.5 kg/m2 ) and obesity (BMI ≥ 25 kg/m2 ) were categorized according to the World Health Organization recommendations for Asian populations.

RESULTS

During a mean follow-up period of 9.2 ± 1.1 years, 26 406 participants were diagnosed with end-stage kidney disease. After fully adjusting for other potential predictors, the moderate to severe underweight group (<17 kg/m2 ) had a significantly higher risk of end-stage kidney disease than that of the reference (normal) weight group (adjusted hazard ratio, 1.563; 95% confidence interval, 1.337-1.828), and competing risk analysis to address the competing risk of death also showed the similar results (adjusted hazard ratio, 1.228; 95% confidence interval, 1.042-1.448). Compared with that of the reference BMI group (24-25 kg/m2 ), the adjusted hazard ratios for end-stage kidney disease increased as the BMI decreased by 1 kg/m2 . In the sensitivity analysis, sustained underweight status or progression to underweight status over two repeated health checkups, when compared with normal weight status, had a higher hazard ratio for end-stage kidney disease.

CONCLUSIONS

Underweight status is associated with an increased risk of end-stage kidney disease, and this association gradually strengthens as BMI decreases.

Evaluation of glomerular filtration rate estimation equations based on serum creatinine in healthy Chinese children and adolescents: a nationwide cross-sectional study

BACKGROUND

Several equations for glomerular filtration rate (GFR) estimation based on serum creatinine (SCr) have been proposed for children, but most were developed among patients with kidney disease. The association between SCr and GFR may be distorted by kidney dysfunction and thus not applicable to healthy children. This study aimed to evaluate the applicability of existing SCr-based GFR estimation equations in healthy Chinese children.

METHODS

GFR estimation equations that developed in healthy children were mainly analysed, including the Flanders Metadata (FM), simple height-independent (Simple), full age spectrum (FAS) and FAS-height equations. The FM equation assumed that GFR is proportional to the ratio of height to SCr. The Simple, FAS and FAS-height equations assumed that the ratio of GFR to population mean is equal to the reciprocal ratio of SCr to population mean (denoted by Q). Estimated GFR were calculated using data of SCr, age, sex and height collected from 12 208 healthy Chinese children aged 3 months to <20 years. The performance of GFR estimation equations was evaluated by the sex and age distribution of the estimated GFR and the deviation from the measured GFR reported by other literatures.

RESULTS

The FM and Simple equations performed well in their applicable age of 1 month to 14 years, but presented undesirable sex difference after adolescence. The FAS and FAS-height equations showed reasonable development trend of estimated GFR throughout childhood, and the FAS equation had higher consistency than the FAS-height equation compared with measured GFR in healthy children. The GFR estimated by the FAS equation increased with age before 2 years, and reached the adult level thereafter without important sex difference.

CONCLUSIONS

The FAS equation is applicable to healthy Chinese children.

Crystalluria in adolescent and adult patients with congenital heart disease

INTRODUCTION

Crystalluria is a frequent finding in normal individuals and in patients suffering from urolithiasis. As nephrolithiasis has been associated with cardiovascular risk factors and most congenital heart disease (CHD) patients reach adulthood, the objective of this study is to determine the presence of crystalluria and if it influences their cardiovascular outcome.

METHODS

Case-control and observational prospective study design of patients with CHD older than 14 years with a stable CHD verified with imaging tests and a control population.

RESULTS

214 patients with CHD [median age 21 (17-35) years and 41 (19%) males] and 345 controls were studied and followed up. None of them had symptoms of renal calculi. Nine (4%) patients with CHD and 24 (7%) patients in the control group showed crystalluria (p = 0.180), all of them composed of calcium oxalate. No significant differences were seen in age, sex, body mass index, CHD complexity, cardiovascular risk factors, NYHA functional class, cyanosis, and medical treatment between CHD patients with and without crystalluria. In relation to survival, 18 patients with CHD had a major acute cardiovascular event (MACE) (3 strokes, 2 myocardial infarction, 9 cardiovascular death and 4 non cardiovascular mortality) during the follow up time [7.3 (4.4-8.5) years] without significant differences in the Kaplan-Meier analysis (p = 0.358) between patients with and without crystalluria.

CONCLUSION

No significant differences were found between CHD and control patients in relation to crystalluria and it had no impact on the occurrence of cardiovascular events in the medium term follow up of patients with CHD.

Admission serum creatinine in non-hemodialysis-dependent patients with spontaneous supratentorial intracerebral hemorrhage: Is it a prognosticator?

INTRODUCTION

Spontaneous intracerebral hemorrhage (ICH) carries a high mortality rate, with end-stage renal disease (ESRD) and hemodialysis being risk factors for early mortality. However, the role of admission serum creatinine in ICH prognosis remains unclear. This study aimed to analyze the correlation between admission serum creatinine levels and short-term ICH prognosis in non-hemodialysis-dependent patients.

METHODS

This retrospective study analyzed 296 adult patients admitted with spontaneous supratentorial ICH. Demographic, clinical, and radiographic data were collected, including admission serum creatinine levels. The primary outcomes were mortality and unfavorable outcomes, defined as Modified Rankin Scale scores of 4-6. Univariate or multivariate analysis was performed to examine the association between admission serum creatinine levels and ICH prognosis, with and without the inclusion of maintenance hemodialysis patients.

RESULTS

Among all patients, elevated admission serum creatinine levels were significantly associated with increased mortality (OR = 1.39, 95% CI: 1.21-1.59, P < 0.01). However, this association disappeared when excluding patients undergoing maintenance hemodialysis (OR = 0.95, 95% CI: 0.53-1.69, P = 0.86). No significant association was found between admission serum creatinine levels and unfavorable outcomes. Other well-established prognostic factors, such as age and admission GCS, demonstrated significant associations with both mortality and unfavorable outcomes in multivariate analysis.

CONCLUSION

Admission serum creatinine appears to have limited prognostic value in non-hemodialysis-dependent patients with spontaneous supratentorial ICH. Our findings suggest that the relationship between renal function and ICH prognosis is complex and may be influenced by factors such as comorbidities and maintenance hemodialysis.

Research progress in functional magnetic resonance imaging assessment of lupus nephritis kidney injury

Lupus nephritis is one of the most common and severe complications of systemic lupus erythematosus and is also a major predictor of poor prognosis and mortality. Lupus nephritis has the characteristics of insidious onset, complex pathological types, rapid progression of organ damage, and easy recurrence. Currently, kidney damage in lupus nephritis is usually assessed based on urine analysis, renal biopsy, and glomerular filtration rates. However, they all have certain limitations, making it difficult to diagnose lupus nephritis early and assess its severity and progression. With the rapid development of functional magnetic resonance, multiple functional imaging techniques are expected to provide more useful information for the pathophysiological development, early diagnosis, progression, prognosis, and renal function evaluation of lupus nephritis. This article reviews the principle of multiple functional magnetic resonance imaging and the research status of evaluating renal function in lupus nephritis.

The Association Between Metabolic Syndrome, Hyperfiltration, and Long-Term GFR Decline in the General Population

Introduction

One-quarter of adults worldwide meet the criteria of metabolic syndrome (MetS). MetS increases the risk of diabetes, chronic kidney disease (CKD), and cardiovascular disease. However, the association between MetS, hyperfiltration, and long-term glomerular filtration rate (GFR) decline in the general population is unknown.

Methods

In the Renal Iohexol Clearance Survey (RENIS), we investigated 1551 people aged 50 to 63 years; representative of the general population without diabetes, cardiovascular disease, or kidney disease. The GFR was measured using iohexol clearance at baseline and twice during 11 years of follow-up. Hyperfiltration at baseline was defined as an absolute GFR (ml/min) above the 90th percentile adjusted for sex, age, and height, because these variables correlate with nephron number. MetS was defined as increased waist circumference and 2 risk factors among hypertension, hyperglycemia, elevated triglycerides, and low high density lipoprotein (HDL)-cholesterol levels. The GFR decline rate was calculated using linear mixed models.

Results

MetS was associated with hyperfiltration at baseline (odds ratio [OR] 2.4; 95% CI: 1.7-3.5, P < 0.001) and a steeper GFR decline rate during follow-up (-0.30 [-0.43 to -0.16] ml/min per 1.73 m2/yr). Compared to those without MetS, GFR decline was -0.83 (95% CI: -1.13 to -0.53) ml/min per 1.73 m2/yr in those with MetS and baseline hyperfiltration and -0.15 (-0.30 to 0.00) in those MetS without hyperfiltration, P = 0.2 for interaction.

Conclusions

In the nondiabetic general population, those with MetS had an increased OR of hyperfiltration and steeper long-term GFR decline. Randomized controlled trials are needed to explore whether treatment of hyperfiltration can prevent loss of GFR in persons with MetS.

Discrepancies between Cystatin C-Based and Creatinine-Based eGFR

BACKGROUND

Recent guidance suggests clinicians increase use of cystatin C for the estimation of GFR. Discrepant levels of creatinine- versus cystatin C-based eGFR (eGFRcr versus eGFRcys) can occur and might signify inaccurate estimation of GFR using creatinine alone. This study sought to enhance the knowledge of the risk factors and clinical implications of having a large eGFR discrepancy.

METHODS

Participants in the Atherosclerosis Risk in Communities Study, a prospective cohort study of US adults, were followed over 25 years. eGFR discrepancy was measured at five clinical visits and defined as eGFRcys either 30% lower or higher than eGFRcr, the current clinical standard of care. The associations between eGFR discrepancies and kidney-related laboratory parameters were assessed using linear and logistic regression and long-term adverse outcomes, including kidney failure, AKI, heart failure, and death, using Cox proportional hazards models.

RESULTS

Among 13,197 individuals (mean age 57 [SD 6] years, 56% women, 25% Black race), 7% had eGFRcys 30% lower than eGFRcr at visit 2 (1990-1992), and this proportion increased over time to 23% by visit 6 (2016-2017). By contrast, the percent with eGFRcys 30% higher than eGFRcr was relatively stable (3%-1%). Independent risk factors for having eGFRcys 30% lower than eGFRcr included older age, female sex, non-Black race, higher eGFRcr, higher body mass index, weight loss, and current smoking. Those with eGFRcys 30% lower than eGFRcr had more anemia and higher uric acid, fibroblast growth factor 23, and phosphate levels as well as higher risk of subsequent mortality, kidney failure, AKI, and heart failure compared with those with similar eGFRcr and eGFRcys values.

CONCLUSIONS

Having eGFRcys lower than eGFRcr was associated with worse kidney-related laboratory derangements and a higher risk of adverse health outcomes.

PODCAST

This article contains a podcast at https://dts.podtrac.com/redirect.mp3/www.asn-online.org/media/podcast/CJASN/2023_09_08_CJN0000000000000217.mp3.

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), β2-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 β2-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 β2-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.

Comparison of the performance of currently used estimated glomerular filtration rate equations with 24-hour urine creatinine clearance: sample analysis of randomised controlled trial participants

OBJECTIVE

There are several equations for estimating the glomerular filtration rate (GFR), and each method has its limitations. We compared various estimated GFR (eGFR) equations with 24 hours urine creatinine clearance (24u-CCr).

DESIGN

Sample analysis of randomised controlled trial participants.

SETTING AND PARTICIPANTS

We compared the mean 24u-CCr values measured 2-3 times for 211 patients with eGFR values calculated using the following equations: isotope dilution mass spectrometry-Modification of Diet in Renal Disease (IDMS-MDRD) equation, Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation, equations for Koreans (KOR-IDMS-MDRD and KOR-CKD-EPI) and full age spectrum equation.

OUTCOME MEASURES

Performance of various creatinine-based eGFR equations, including those with Korean coefficients, compared with the results of the 24u-CCr.

RESULTS

IDMS-MDRD showed the best overall correlation with the 24u-CCr (R=0.949, p<0.001), and KOR-CKD-EPI showed the best agreement in terms of the intraclass correlation coefficient (ICC, 0.969, 95% CI 0.959 to 0.976, p<0.001). In subgroup analysis, IDMS-MDRD-GFR showed the highest ICCs in CKD stages 1 and 3 (ICC 0.872 in stage 1 and 0.927 in CKD stage 3, all p<0.001). KOR-CKD-EPI showed the highest ICC in CKD stage 2 (ICC 0.854, p<0.001). Overall, the accuracy of CKD-EPI (2021) was the highest at P15 (15%) and P30 (30%) (P15: 65.4 and P30: 97.6). In addition, CKD-EPI (2021) showed the highest P30 accuracy in CKD stage 1 (98.7), whereas KOR-IDMS-MDRD showed the highest P30 accuracy in CKD stages 2 and 3 (98.8 and 98.2, respectively).

CONCLUSIONS

The IDMS-MDRD equation showed the best correlation and overall good agreement with the 24u-CCr; however, the accuracy was low. The most accurate measurements were obtained using the CKD-EPI (2021) equation in CKD stage 1 and the KOR-IDMS-MDRD equation in CKD stages 2-3; nevertheless, the CKD-EPI (2021) equation showed the best overall accuracy.

TRIAL REGISTRATION NUMBER

NCT01552954.

Kidney function, albuminuria, and their modification by genetic factors and risk of incident dementia in UK Biobank

BACKGROUND

Associations between kidney function and dementia risk are inconclusive. Chronic kidney disease (CKD) severity is determined by levels of both estimated glomerular filtration rate (eGFR) and the urine albumin to creatinine ratio (ACR). However, whether there is a graded increase in dementia risk for worse eGFR in each ACR category is unclear. Also, whether genetic risk for dementia impacts the associations is unknown. The current study aims to investigate the associations between eGFR and albuminuria with dementia risk both individually and jointly, whether the associations vary by different follow-up periods, and whether genetic factors modified the associations.

METHODS

In 202,702 participants aged ≥ 60 years from the UK Biobank, Cox proportional-hazards models were used to examine the associations between eGFR and urine albumin creatinine ratio (ACR) with risk of incident dementia. GFR was estimated based on serum creatinine, cystatin C, or both. The models were restricted to different follow-up periods (< 5 years, 5-10 years, and ≥ 10 years) to investigate potential reverse causation.

RESULTS

Over 15 years of follow-up, 6,042 participants developed dementia. Decreased kidney function (eGFR < 60 ml/min/1.73m2) was associated with an increased risk of dementia (Hazard Ratio [HR] = 1.42, 95% Confidence Interval [CI] 1.28-1.58), compared to normal kidney function (≥ 90 ml/min/1.73m2). The strength of the association remained consistent when the models were restricted to different periods of follow-up. The HRs for incident dementia were 1.16 (95% CI 1.07-1.26) and 2.24 (95% CI 1.79-2.80) for moderate (3-30 mg/mmol) and severely increased ACR (≥ 30 mg/mmol) compared to normal ACR (< 3 mg/mmol). Dose-response associations were observed when combining eGFR and ACR, with those in the severest eGFR and ACR group having the greatest risk of dementia (HR = 4.70, 95% CI 2.34-9.43). APOE status significantly modified the association (p = 0.04), with stronger associations observed among participants with a lower genetic risk of dementia. There was no evidence of an interaction between kidney function and non-APOE polygenic risk of dementia with dementia risk (p = 0.42).

CONCLUSIONS

Kidney dysfunction and albuminuria were individually and jointly associated with higher dementia risk. The associations were greater amongst participants with a lower genetic risk of dementia based on APOE, but not non-APOE polygenic risk.

Cystatin C is glucocorticoid responsive, directs recruitment of Trem2+ macrophages, and predicts failure of cancer immunotherapy

Cystatin C (CyC), a secreted cysteine protease inhibitor, has unclear biological functions. Many patients exhibit elevated plasma CyC levels, particularly during glucocorticoid (GC) treatment. This study links GCs with CyC's systemic regulation by utilizing genome-wide association and structural equation modeling to determine CyC production genetics in the UK Biobank. Both CyC production and a polygenic score (PGS) capturing predisposition to CyC production were associated with increased all-cause and cancer-specific mortality. We found that the GC receptor directly targets CyC, leading to GC-responsive CyC secretion in macrophages and cancer cells. CyC-knockout tumors displayed significantly reduced growth and diminished recruitment of TREM2+ macrophages, which have been connected to cancer immunotherapy failure. Furthermore, the CyC-production PGS predicted checkpoint immunotherapy failure in 685 patients with metastatic cancer from combined clinical trial cohorts. In conclusion, CyC may act as a GC effector pathway via TREM2+ macrophage recruitment and may be a potential target for combination cancer immunotherapy.

Pharmacological Nephroprotection in Non-Diabetic Chronic Kidney Disease-Clinical Practice Position Statement of the Polish Society of Nephrology

Chronic kidney disease (CKD) is a modern epidemic worldwide. Introducing renin-angiotensin system (RAS) inhibitors (i.e., ACEi or ARB) not only as blood-pressure-lowering agents, but also as nephroprotective drugs with antiproteinuric potential was a milestone in the therapy of CKD. For decades, this treatment remained the only proven strategy to slow down CKD progression. This situation changed some years ago primarily due to the introduction of drugs designed to treat diabetes that turned into nephroprotective strategies not only in diabetic kidney disease, but also in CKD unrelated to diabetes. In addition, several drugs emerged that precisely target the pathogenetic mechanisms of particular kidney diseases. Finally, the role of metabolic acidosis in CKD progression (and not only the sequelae of CKD) came to light. In this review, we aim to comprehensively discuss all relevant therapies that slow down the progression of non-diabetic kidney disease, including the lowering of blood pressure, through the nephroprotective effects of ACEi/ARB and spironolactone independent from BP lowering, as well as the role of sodium-glucose co-transporter type 2 inhibitors, acidosis correction and disease-specific treatment strategies. We also briefly address the therapies that attempt to slow down the progression of CKD, which did not confirm this effect. We are convinced that our in-depth review with practical statements on multiple aspects of treatment offered to non-diabetic CKD fills the existing gap in the available literature. We believe that it may help clinicians who take care of CKD patients in their practice. Finally, we propose the strategy that should be implemented in most non-diabetic CKD patients to prevent disease progression.

Assessment of Renal Function of Bodybuilders Using Anabolic Androgenic Steroids and Diet Supplements

Introduction Anabolic androgenic steroids (AAS) and diet supplements (DS) are frequently used by bodybuilders. In this specific group, increased muscle mass, the acute effects of exercise, and the use of creatine may affect the creatinine-based estimated glomerular filtration rate (eGFRcr), potentially leading to an underestimation of the GFR. Cystatin C equations offer a more accurate prediction of GFR that is independent of muscle mass. We aimed to assess the renal functions of bodybuilders who use both AAS+DS, as well as those who only use DS, by calculating the GFR based on cystatin C (eGFRcys) and also using a combination of cystatin C and creatinine (eGFRcys/cr). Methods The study included 12 bodybuilders using AAS+DS and 12 bodybuilders using DS. In both groups, serum cystatin C levels, eGFRcys, eGFRcys/cr, urine albumin excretion rates, urine protein excretion rates, and routine tests were examined. Results In AAS+DS users, the average duration of AAS use was 3.08±2.02 years, while for DS users, the duration of supplement use was 3.67±2.49 years. The spot urine albumin/creatinine and protein/creatinine ratios were higher in AAS+DS users (p<0.001 and p=0.006, respectively). Although eGFRcr was found to be similar in the AAS+DS and DS groups (119.67 ± 24.12 ml/min and 122.08 ± 18.03 ml/min, respectively; p=0.426), eGFRcys and the eGFRcys/cr ratio were significantly lower in the AAS+DS group compared to the DS group (eGFRcys: 120.67 ± 19.48 ml/min vs. 122.08 ± 18.03 ml/min, p=0.039; eGFRcys/cr: 121.83 ± 20.62 ml/min vs. 126.33 ± 21.163 ml/min, p= 0.036, respectively). Conclusion Cystatin-based GFR values were found to be significantly lower in AAS+DS users, and urinary albumin and protein excretion were considerably higher compared to DS users. Although these findings suggest a potential link between early kidney damage and the direct use of AAS, the topic requires further investigation.

Concordance between glomerular filtration rate estimation equations and 4-hour urinary creatinine clearance in critically ill patients with severe trauma

BACKGROUND AND OBJECTIVE

There is a growing body of evidence that the equations used to estimate the glomerular filtration rate (GFR) are not suitable in critically ill patients, a population whose GFR fluctuates continuously. Glomerular filtration is usually estimated by measuring urine creatinine clearance (CrCl) at various time points. The aim of our study was to evaluate the performance of the most widely used GFR calculators in the subpopulation of critically ill patients admitted for severe trauma, and to compare the results against determinations of CrCl in urine collected over a 4-h period (4h-CrCl).

MATERIAL AND METHODS

Observational study in patients hospitalized for severe trauma. We measured the 4h-CrCl and estimated GFR using the Cockcroft-Gault, modified Jelliffe, MDRD, t-MDRD, and CKD-EPI equations, adjusting the results for body surface area (BSA) (ml/min/1.73m2). Data were analysed using R version 4.0.4.

RESULTS

A total of 85 patients were included. Median age was 51 years, and 68 were men (78.82%). The mean BSA-adjusted 4h-CrCl (4h-ClCr/1.73m2) was 84.5 ml/min/1.73m2. We found that GFR estimated using the t-MDRD equation correlated significantly with 4h-CrCl/1.73m2. The Cockcroft-Gault equation correlated significantly with 4h-CrCl/1.73m2 when GFR was greater than 130ml/min/m2.

CONCLUSIONS

In ICU patients, glomerular filtration can be reliably estimated by determining urine CrCl, but GFR calculators are not accurate in this population.

Evolution of estimated glomerular filtration rate in HIV/HCV-coinfected patients who received direct-acting antivirals: A multicenter retrospective study

BACKGROUND

The short-term impact of sofosbuvir (SOF)-based direct-acting antivirals (DAAs) combined with antiretroviral therapy (ART) on renal function in patients with HIV/HCV-coinfection remains controversial.

METHODS

This multicenter, retrospective study aimed to sequentially record the estimated glomerular filtration rate (eGFR) at baseline, end of therapy (EOT), 12 weeks off-treatment (SVR12), and at time points after SVR12 (post-SVR12) and to identify the factors associated with an eGFR decline to <60 ml/min/1.73 m2 in HIV/HCV-coinfected patients receiving DAAs. The evolution of mean eGFRs between different ART and DAAs combinations among patients of different HIV transmission routes were compared using a generalized linear mixed effects model. The periods between baseline and EOT, between EOT and post-SVR12, and between baseline and post-SVR12 were defined as the on-treatment, post-treatment, and all-course periods, respectively. Acute kidney disease (AKD) was defined as a decline of eGFR to <60 ml/min/1.73 m2.

RESULT

A total of 445 patients with baseline eGFRs >60 ml/min/1.73 m2 were included. We found that eGFRs declined during the on-treatment period in the tenofovir-containing ART and SOF-based DAA groups. There were no differences in the slope coefficient during the on-treatment and post-treatment periods among all risk groups except for people who inject drug. Increasing age and plasma HIV RNA >20 copies/ml before DAA treatment were factors independently associated with AKD during the on-treatment period while increasing age was independently associated with AKD during the all-course period.

CONCLUSION

Only increasing age was an independent factor associated with AKD among HIV/HCV-coinfected patients during and after DAA treatments.

Validation of eGFR for Detecting Associations Between Serum Protein Biomarkers and Subsequent GFR Decline

SIGNIFICANCE STATEMENT

eGFR from creatinine, cystatin C, or both has been primarily used in search of biomarkers for GFR decline. Whether the relationships between biomarkers and eGFR decline are similar to associations with measured GFR (mGFR) decline has not been investigated. This study revealed that some biomarkers showed statistically significant different associations with eGFR decline compared with mGFR decline, particularly for eGFR from cystatin C. The findings indicate that non-GFR-related factors, such as age, sex, and body mass index, influence the relationship between biomarkers and eGFR decline. Therefore, the results of biomarker studies using eGFR, particularly eGFRcys, should be interpreted with caution and perhaps validated with mGFR.

BACKGROUND

Several serum protein biomarkers have been proposed as risk factors for GFR decline using eGFR from creatinine or cystatin C. We investigated whether eGFR can be used as a surrogate end point for measured GFR (mGFR) when searching for biomarkers associated with GFR decline.

METHODS

In the Renal Iohexol Clearance Survey, GFR was measured with plasma iohexol clearance in 1627 individuals without diabetes, kidney, or cardiovascular disease at baseline. After 11 years of follow-up, 1409 participants had one or more follow-up GFR measurements. Using logistic regression and interval-censored Cox regression, we analyzed the association between baseline levels of 12 serum protein biomarkers with the risk of accelerated GFR decline and incident CKD for both mGFR and eGFR.

RESULTS

Several biomarkers exhibited different associations with eGFR decline compared with their association with mGFR decline. More biomarkers showed different associations with eGFRcys decline than with eGFRcre decline. Most of the different associations of eGFR decline versus mGFR decline remained statistically significant after adjustment for age, sex, and body mass index, but several were attenuated and not significant after adjusting for the corresponding baseline mGFR or eGFR.

CONCLUSIONS

In studies of some serum protein biomarkers, eGFR decline may not be an appropriate surrogate outcome for mGFR decline. Although the differences from mGFR decline are attenuated by adjustment for confounding factors in most cases, some persist. Therefore, proposed biomarkers from studies using eGFR should preferably be validated with mGFR.

Association between enhanced carbonyl stress and decreased apparent axonal density in schizophrenia by multimodal white matter imaging

Carbonyl stress is a condition featuring increased rich reactive carbonyl compounds, which facilitate the formation of advanced glycation end products including pentosidine. We previously reported the relationship between enhanced carbonyl stress and disrupted white matter integrity in schizophrenia, although which microstructural component is disrupted remained unclear. In this study, 32 patients with schizophrenia (SCZ) and 45 age- and gender-matched healthy volunteers (HC) were recruited. We obtained blood samples for carbonyl stress markers (plasma pentosidine and serum pyridoxal) and multi-modal magnetic resonance imaging measures of white matter microstructures including apparent axonal density (intra-cellular volume fraction (ICVF)) and orientation (orientation dispersion index (ODI)), and inflammation (free water (FW)). In SCZ, the plasma pentosidine level was significantly increased. Group comparison revealed that mean white matter values were decreased for ICVF, and increased for FW. We found a significant negative correlation between the plasma pentosidine level and mean ICVF values in SCZ, and a significant negative correlation between the serum pyridoxal level and mean ODI value in HC, regardless of age. Our results suggest an association between enhanced carbonyl stress and axonal abnormality in SCZ.

Population pharmacokinetics of amikacin in suspected cases of neonatal sepsis

AIMS

This study aimed to characterize the population pharmacokinetic parameters of intravenously administered amikacin in newborns and assess the effect of sepsis in amikacin exposure.

METHODS

Newborns aged ≥3 days who received at least 1 dose of amikacin during their hospitalization period were eligible for the study. Amikacin was administered intravenously during a 60-min infusion period. Three venous blood samples were taken from each patient during the first 48 h. Population pharmacokinetic parameter estimates were obtained using a population approach with the programme NONMEM.

RESULTS

Data from 329 drug assay samples were obtained from 116 newborn patients (postmenstrual age [PMA] 38.3, range 32-42.4 weeks; weight 2.8, range 1.6-3.8 kg). Measured amikacin concentrations ranged from 0.8 to 56.4 mg/L. A 2-compartment model with linear elimination produced a good fit of the data. Estimated parameters for a typical subject (2.8 kg, 38.3 weeks) were clearance (Cl = 0.16 L/h), intercompartmental clearance (Q = 0.15 L/h), volume of distribution of the central compartment (Vc = 0.98 L) and peripheral volume of distribution (Vp = 1.23 L). Total bodyweight, PMA and the presence of sepsis positively influenced Cl. Plasma creatinine concentration and circulatory instability (shock) negatively influenced Cl.

CONCLUSION

Our main results confirm previous findings showing that weight, PMA and renal function are relevant factors influencing newborn amikacin pharmacokinetics. In addition, current results showed that pathophysiological states of critically ill neonates, such as sepsis and shock, were associated with opposite effects in amikacin clearance and should be considered in dose adjustments.

Diagnosis of Chronic Kidney Disease and Assessing Glomerular Filtration Rate

Chronic kidney disease (CKD) is a silent progressive disease. It is diagnosed by assessing filtration and markers of kidney damage such as albuminuria. The diagnosis of CKD should include not only assessing the glomerular filtration rate (GFR) and albuminuria but also the cause. The CKD care plan should include documentation of the trajectory and prognosis. The use of a combination of serum cystatin C and creatinine concentration offers a more accurate estimation of GFR. Social determinants of health are important to address as part of the diagnosis because they contribute to CKD disparities.

Risk for Chronic Kidney Disease Progression After Acute Kidney Injury: Findings From the Chronic Renal Insufficiency Cohort Study

BACKGROUND

Prior studies associating acute kidney injury (AKI) with more rapid subsequent loss of kidney function had methodological limitations, including inadequate control for differences between patients who had AKI and those who did not.

OBJECTIVE

To determine whether AKI is independently associated with subsequent kidney function trajectory among patients with chronic kidney disease (CKD).

DESIGN

Multicenter prospective cohort study.

SETTING

United States.

PARTICIPANTS

Patients with CKD (n = 3150).

MEASUREMENTS

Hospitalized AKI was defined by a 50% or greater increase in inpatient serum creatinine (SCr) level from nadir to peak. Kidney function trajectory was assessed using estimated glomerular filtration rate (eGFR) based on SCr level (eGFRcr) or cystatin C level (eGFRcys) measured at annual study visits.

RESULTS

During a median follow-up of 3.9 years, 433 participants had at least 1 AKI episode. Most episodes (92%) had stage 1 or 2 severity. There were decreases in eGFRcr (-2.30 [95% CI, -3.70 to -0.86] mL/min/1.73 m2) and eGFRcys (-3.61 [CI, -6.39 to -0.82] mL/min/1.73 m2) after AKI. However, in fully adjusted models, the decreases were attenuated to -0.38 (CI, -1.35 to 0.59) mL/min/1.73 m2 for eGFRcr and -0.15 (CI, -2.16 to 1.86) mL/min/1.73 m2 for eGFRcys, and the CI bounds included the possibility of no effect. Estimates of changes in eGFR slope after AKI determined by either SCr level (0.04 [CI, -0.30 to 0.38] mL/min/1.73 m2 per year) or cystatin C level (-0.56 [CI, -1.28 to 0.17] mL/min/1.73 m2 per year) also had CI bounds that included the possibility of no effect.

LIMITATIONS

Few cases of severe AKI, no adjudication of AKI cause, and lack of information about nephrotoxic exposures after hospital discharge.

CONCLUSION

After pre-AKI eGFR, proteinuria, and other covariables were accounted for, the association between mild to moderate AKI and worsening subsequent kidney function in patients with CKD was small.

PRIMARY FUNDING SOURCE

National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health.

Vitamin C injection improves antioxidant stress capacity through regulating blood metabolism in post-transit yak

Transportation stress is one of the most serious issues in the management of yak. Previous studies have demonstrated that transport stress is caused by a pro-oxidant state in the animal resulting from an imbalance between pro-oxidant and antioxidant status. In this context, vitamin C has the ability to regulate reactive oxygen species (ROS) synthesis and alleviate oxidative stress. Although this effect of vitamin C is useful in pigs, goats and cattle, the effect of vitamin C on the mitigation of transport stress in yaks is still unclear. The purpose of this study was to better assess the metabolic changes induced by the action of vitamin C in yaks under transportation stress, and whether these changes can influence antioxidant status. After the yaks arrived at the farm, control or baseline blood samples were collected immediately through the jugular vein (VC_CON). Then, 100 mg/kg VC was injected intramuscularly, and blood samples were collected on the 10th day before feeding in the morning (VC). Relative to the control group, the VC injection group had higher levels of VC. Compared with VC_CON, VC injection significantly (P < 0.05) decreased the blood concentrations of ALT, AST, T-Bil, D-Bil, IDBIL, UREA, CRP and LDH. However, VC injection led to greater (P < 0.05) AST/ALT and CREA-S relative to VC_CON. There was no difference (P > 0.05) in GGT, ALP, TBA, TP, ALBII, GLO, A/G, TC, TG, HDL-C, LDL-C, GLU and L-lactate between VC_CON and VC. The injection of VC led to greater (P < 0.05) concentration of MDA, but did not alter (P > 0.05) the serum concentrations of LPO and ROS. The injection of VC led to greater (P < 0.05) serum concentrations of POD, CAT and GSH-PX. In contrast, lower (P < 0.05) serum concentrations of SOD, POD and TPX were observed in VC relative to VC_CON. No difference (P > 0.05) in GSH, GSH-ST and GR was observed between VC_CON and VC. Compared with the control group, metabolomics using liquid chromatography tandem-mass spectrometry identified 156 differential metabolites with P < 0.05 and a variable importance in projection (VIP) score > 1.5 in the VC injection group. The injection of VC resulted in significant changes to the intracellular amino acid metabolism of glutathione, glutamate, cysteine, methionine, glycine, phenylalanine, tyrosine, tryptophan, alanine and aspartate. Overall, our study indicated that VC injections were able to modulate antioxidant levels by affecting metabolism to resist oxidative stress generated during transport.

Protective Action Mechanisms of Launaea mucronata Extract and Its Nano-Formulation against Nephrotoxicity in Rats as Revealed via Biochemical, Histopathological, and UPLC-QTOF-MS/MS Analyses

Plants belonging to the Launaea genus have been extensively utilized ethnopharmacologically to treat a variety of diseases, including kidney disorders. Chromium is a common industrial pollutant that has been linked to kidney disease. The present work was designed for the investigation of the UPLC-QTOF-MS/MS metabolite profile of the L. mucronate ethanolic extract (LME), along with assessing the mechanistic protective actions of LME and its nano-silver formulation (LMNS) against K₂Cr₂O₇-induced nephrotoxicity in rats. LMNE was successfully biosynthesized and confirmed using UV-Visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM). The nephroprotective effects of LME and LMNE was assessed in rats exposed to potassium dichromate (K₂Cr₂O₇, 15 mg/kg BW) to cause nephrotoxicity. LME and LMNS, separately, were administered twice daily for 14 days at doses of 200 and 400 mg/kg BW, respectively. The kidney function, catalase, UGT, Nrf2, PGE2, Cox-2, ERK, and MAPK levels in renal tissue were all assessed, along with histopathological examinations for exploring their ameliorative effects. Forty-five bioactive metabolites were annotated belonging to flavonoids, phenolic and organic acids, coumarins, and fatty acids. Metabolite profiling revealed that chlorogenic acid, apigenin, and luteolin glycosides were the main phenolics, with chlorogenic acid-O-hexoside reported for the first time in LME. The findings revealed that the serum kidney function indicators (urea and creatinine) were markedly elevated in K₂Cr₂O₇-intoxicated rats. Furthermore, inflammatory indicators (COX-2 and PGE2), MAPK, and ERK were all markedly elevated in kidney tissue, whereas catalase, UGT, and Nrf2 levels were downregulated. Histological and immunohistochemical assays confirmed the toxic effects of K₂Cr₂O₇ in the kidneys. In contrast, the administration of LME and LMNS prior to K₂Cr₂O₇ considerably improved the architecture of the renal tissue, while also restoring levels of most biochemical markers. Functioning via the inhibition of the MAPK/ERK pathway, activating Nrf2, and modifying the antioxidant and metabolic enzymes, LME and LMNS exerted their nephroprotective effects against K₂Cr₂O₇-induced toxicity.

Predicting AKI in patients with AMI: Development and assessment of a new predictive nomogram

Acute kidney injury (AKI) is a common complication of acute myocardial infarction (AMI) and is associated with both long- and short-term consequences. This study aimed to investigate relevant risk variables and create a nomogram that predicts the probability of AKI in patients with AMI, so that prophylaxis could be initiated as early as possible. Data were gathered from the medical information mart for the intensive care IV database. We included 1520 patients with AMI who were admitted to the coronary care unit or the cardiac vascular intensive care unit. The primary outcome was AKI during hospitalization. Independent risk factors for AKI were identified by applying least absolute shrinkage and selection operator regression models and multivariate logistic regression analyses. A multivariate logistic regression analysis was used to build a predictive model. The discrimination, calibration, and clinical usefulness of the prediction model were assessed using C-index, calibration plot, and decision curve analysis. Internal validation was assessed using bootstrapping validation. Of 1520 patients, 731 (48.09%) developed AKI during hospitalization. Hemoglobin, estimated glomerular filtration rate, sodium, bicarbonate, total bilirubin, age, heart failure, and diabetes were identified as predictive factors for the nomogram construction (P < .01). The model displayed good discrimination, with a C-index of 0.857 (95% CI:0.807-0.907), and good calibration. A high C-index value of 0.847 could still be reached during interval validation. Decision curve analysis showed that the AKI nomogram was clinically useful when the intervention was determined at an AKI possibility threshold of 10%. The nomogram constructed herein can successfully predict the risk of AKI in patients with AMI early and provide critical information that can facilitate prompt and efficient interventions.

Comparison of Three Glomerular Filtration Rate Estimating Equations with 24-Hour Urine Creatinine Clearance Measurement in Potential Living Kidney Donors

Background

The accuracy of the measurement of renal function in potential living kidney donors (PLKD) is essential. The direct measurement of glomerular filtration rate (mGFR) has been considered the "gold standard." The estimated GFR (eGFR) with 24-hour urinary creatinine clearance (CrCl) is frequently used because of its availability. We aim to evaluate the correlation and agreement of eGFR using serum-based creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI) and the eGFR based on 24-hour urinary CrCl to evaluate kidney function in PLKD.

Methods

We evaluated the kidney function in 799 PLKD using 24-hour urinary CrCl method and compared the correlation and agreement with the eGFR based on creatinine formulas (Cockcroft-Gault, MDRD, and CKD-EPI). We calculated the mean bias (difference), precision (SD of this difference), accuracy, and performed Bland-Altman plots.

Results

A total of 799 PLKD were analyzed. The age of the PLKD ranged from 18 to 73 years. Weak to mild correlation was observed between 24-hour urinary CrCl and all formulas (ranged from 0.31 to 0.49). The three equations underestimated the GFR. Using the Bland-Altman graphic, we observed that the CKD-EPI was the least scattered and most precise; however, mean bias and the interval range (limits of agreement) of all formulas were too big to assume equivalence between 24-hour urinary CrCl method and eGFR based on creatinine. Results of mean bias were similar when comparing the three equations in patients with CrCl GFR <60. However, the accuracy of all formulas was better for the female group and the youngest individuals (≤40 years old).

Conclusion

In this PLKD cohort, of all the three equations, the CKD-EPI was the least scattered and most precise. However, the correlation and the level of agreement between the three equations and 24-hour urinary CrCl were too low to assume the equivalence.

Validation of the European Kidney Function Consortium Equation in Chinese Adult Population: An Equation Standing on the Shoulders of Predecessors

BACKGROUND

Equations based on serum creatinine (SCr) have been extensively applied to estimate glomerular filtration rate (GFR), but their performance is debatable. In 2021, the European Kidney Function Consortium (EKFC) published one novel SCr-based formula, which combined the feature of Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and full age spectrum (FAS) equations, but its potential applications remain unknown. We seek to assess the appropriateness of the three equations in Chinese adults.

METHODS

A total of 3,692 participants (median age, 54 years) were included. Reference GFR (rGFR) was measured by the 99mTc-DTPA renal dynamic imaging method. Estimated GFR (eGFR) was calculated by the CKD-EPI, FAS, and EKFC equations. Correlation coefficients and Bland-Altman analysis were adopted to evaluate their validity. The performance was assessed in subgroups according to age, sex, rGFR, and SCr, considering the bias, accuracy, and precision.

RESULTS

The average rGFR was 74.2 mL/min/1.73 m2. eGFR by EKFC showed a relatively stronger correlation with rGFR (R = 0.749) and a larger area under the receiver operating characteristic curve (0.902). EKFC was significantly less biased and exhibited the highest P30 in the entire population (bias = 3.61, P30 = 73.3%). It also performed well in all analyzed subgroups, especially in participants with normal or slightly impaired renal function (rGFR≥60 mL/min/1.73 m2), and low SCr.

CONCLUSIONS

Compared to the other two SCr-based formulas, EKFC performed better in the Chinese. Thus, it might serve as a good alternative, until a more suitable formula is developed for the Chinese population.

Novel Model of Oxalate Diet-Induced Chronic Kidney Disease in Dahl-Salt-Sensitive Rats

Diet-induced models of chronic kidney disease (CKD) offer several advantages, including clinical relevance and animal welfare, compared with surgical models. Oxalate is a plant-based, terminal toxic metabolite that is eliminated by the kidneys through glomerular filtration and tubular secretion. An increased load of dietary oxalate leads to supersaturation, calcium oxalate crystal formation, renal tubular obstruction, and eventually CKD. Dahl-Salt-Sensitive (SS) rats are a common strain used to study hypertensive renal disease; however, the characterization of other diet-induced models on this background would allow for comparative studies of CKD within the same strain. In the present study, we hypothesized that SS rats on a low-salt, oxalate rich diet would have increased renal injury and serve as novel, clinically relevant and reproducible CKD rat models. Ten-week-old male SS rats were fed either 0.2% salt normal chow (SS-NC) or a 0.2% salt diet containing 0.67% sodium oxalate (SS-OX) for five weeks.Real-time PCR demonstrated an increased expression of inflammatory marker interleukin-6 (IL-6) (p < 0.0001) and fibrotic marker Timp-1 metalloproteinase (p < 0.0001) in the renal cortex of SS-OX rat kidneys compared with SS-NC. The immunohistochemistry of kidney tissue demonstrated an increase in CD-68 levels, a marker of macrophage infiltration in SS-OX rats (p < 0.001). In addition, SS-OX rats displayed increased 24 h urinary protein excretion (UPE) (p < 0.01) as well as significant elevations in plasma Cystatin C (p < 0.01). Furthermore, the oxalate diet induced hypertension (p < 0.05). A renin-angiotensin-aldosterone system (RAAS) profiling (via liquid chromatography-mass spectrometry; LC-MS) in the SS-OX plasma showed significant (p < 0.05) increases in multiple RAAS metabolites including angiotensin (1-5), angiotensin (1-7), and aldosterone. The oxalate diet induces significant renal inflammation, fibrosis, and renal dysfunction as well as RAAS activation and hypertension in SS rats compared with a normal chow diet. This study introduces a novel diet-induced model to study hypertension and CKD that is more clinically translatable and reproducible than the currently available models.

Prevalence of Augmented Renal Clearance (ARC), Utility of Augmented Renal Clearance Scoring System (ARC score) and Augmented Renal Clearance in Trauma Intensive Care Scoring System (ARCTIC score) in Predicting ARC in the Intensive Care Unit: Proactive Study

Objectives

We aimed to study the prevalence of augmented renal clearance (ARC) and validate the utility of ARC and ARCTIC scores. We also aimed to assess the correlation and agreement between estimated GFR (eGFR-EPI) and 8-hour measured creatinine clearance (8 hr-mCL_cr).

Study design and methodology

This was a prospective, observational study done in the mixed medical-surgical intensive care unit (ICU) and 90 patients were recruited. 8 hr-mCL_cr, ARC, and ARCTIC scores and eGFR-EPI were calculated for all patients. ARC was said to be present if 8 hr-mCLcr was ≥ 130 mL/min.

Results

Four patients were excluded from the analysis. The prevalence of ARC was 31.4%. The sensitivity, specificity, and positive and negative predictive values of ARC and ARCTIC scores were found to be 55.6, 84.7, 62.5, 80.6, and 85.2, 67.8, 54.8, and 90.9 respectively. AUROC for ARC and ARCTIC scores were 0.802 and 0.765 respectively. A strong positive correlation and poor agreement were observed between eGFR-EPI and 8 hr-mCL_cr.

Conclusion

The prevalence of ARC was significant and the ARCTIC score showed good potential as a screening tool to predict ARC. Lowering the cut-off of ARC score to ≥5 improved its utility in predicting ARC. Despite its poor agreement with 8 hr-mCL_cr, eGFR-EPI with a cut-off ≥114 mL/min showed utility in predicting ARC.

How to cite this article

Kanna G, Patodia S, Annigeri RA, Ramakrishnan N, Venkataraman R. Prevalence of Augmented Renal Clearance (ARC), Utility of Augmented Renal Clearance Scoring System (ARC score) and Augmented Renal Clearance in Trauma Intensive Care Scoring System (ARCTIC score) in Predicting ARC in the Intensive Care Unit: Proactive Study. Indian J Crit Care Med 2023;27(6):433-443.

Estimated glomerular filtration rate based on creatinine, cystatin C, β-trace protein and β2 microglobulin in patients undergoing nontraumatic lower extremity amputation

AIMS

The study's aim is to compare current and new equations for estimating glomerular filtration rate (GFR) based on creatinine, cystatin C, β-trace protein (BTP) and β2 microglobulin (B2M) among patients undergoing major amputation.

METHODS

This is a secondary analysis of data from a prospective cohort study investigating patients undergoing nontraumatic lower extremity amputation. Estimated GFR (eGFR) was calculated using equations based on creatinine (eGFRcre[2009] and eGFRcre[2021]), cystatin C (eGFRcys), the combination of creatinine and cystatin C (eGFRcomb[2012] and eGFRcomb[2021]) or a panel of all 4 filtration markers (eGFRpanel). Primary outcome was changed in eGFR across amputation according to each equation. Two case studies of prior amputation with GFR measured by 99mTc-DTPA clearance are described to illustrate the relative accuracies of each eGFR equation.

RESULTS

Analysis of the primary outcome included 29 patients (median age 75 years, 31% female). Amputation was associated with a significant decrease in creatinine concentration (-0.09 mg/dL, P = 0.004), corresponding to a significant increase in eGFRcre[2009] (+6.1 mL/min, P = 0.006) and eGFRcre[2021] (+6.3 mL/min, P = 0.006). Change across amputation was not significant for cystatin C, BTP, B2M or equations incorporating these markers (all P > 0.05). In both case studies, eGFRcre[2021] yielded the largest positive bias, eGFRcys yielded the largest negative bias and eGFRcomb[2012] and eGFRcomb[2021] yielded the smallest absolute bias.

CONCLUSION

Creatinine-based estimates were substantially higher than cystatin C-based estimates before amputation and significantly increased across amputation. Estimates combining creatinine and cystatin were stable across amputation, while the addition of BTP and B2M is unlikely to be clinically relevant.

Inactive matrix Gla protein in relation to diabetic retinopathy in type 2 diabetes

Background and Aims

The contribution of inactive Matrix Gla protein (MGP) to ectopic vascular calcification associated with type 2 diabetes mellitus (T2DM) is well recognized. However, its role in diabetic microvascular complications remains unknown. The study aim was to identify any association between inactive MGP and diabetic retinopathy (DR). Its relation to insulin resistance was also explored.

Methods

The study included 90 participants, 65 Type 2 diabetic patients (25 without DR and 40 with DR) and 25 healthy controls. Serum inactive MGP was measured using ELISA. HOMA-IR was also assessed.

Results

Inactive MGP was significantly higher in both diabetic groups compared to controls (P < 0.001), as well as in Type 2 diabetic patients with retinopathy compared to Type 2 diabetes without retinopathy (P = 0.002). Inactive MGP was positively correlated with HbA1c, HOMA-IR, LDL-C and triglycerides (P < 0.001), and negatively correlated with HDL-C (P = 0.008) and eGFR (P < 0.001). Logistic Regression Analysis showed that inactive MGP was one of the most associated factors with DR.

Conclusions

Inactive MGP was found to be related to DR, insulin resistance and other dysmetabolic risk factors. These findings highlight that inactive MGP may be a significant contributor to the pathogenesis, evolution, and progression of DR.

Controlling nutritional status score predicts 2-year outcomes in elderly patients admitted for acute heart failure

BACKGROUND

Heart failure (HF) is a major cause of death among the elderly. Its prevalence increases dramatically with age. The prevalence of malnourished subjects is high in hospitalized elderly patients. We aimed to investigate the prognostic role of malnutrition, assessed by controlling nutritional status (CONUT) score, on adverse clinical outcomes in the elderly admitted for acute HF.

METHODS

We enrolled 293 patients (mean age 84 years; 48% men) consecutively admitted for acute HF to the Internal Medicine or Geriatrics Divisions at the 'IRCCS Sacro Cuore-Don Calabria' Hospital of Negrar (Verona, Italy) from 2013 to 2015. We predicted the risk of all-cause death, re-hospitalizations for HF and non-HF causes, and the composite of all-cause death or hospitalizations over 2-year follow-up. Patients were divided into four groups according to CONUT score: normal-CONUT (0-1; n = 30); mild-CONUT (2-3; n = 56); moderate-CONUT (4-7; n = 171); and severe-CONUT (≥ 8; n = 36).

RESULTS

Higher CONUT scores were associated with older age and lower entry blood pressures. No difference in hemodynamics was noted at the discharge. Kaplan-Meier curves showed a significant association between worsening CONUT scores and risk of all-cause death (p < 0.01), re-hospitalizations (p < 0.01), or both (p < 0.001). Cox regression analysis revealed these significant associations persisted after adjustment for age, sex, pre-existing cardiovascular disease, diabetes, chronic kidney disease, heart rate, systolic blood pressure, and plasma brain natriuretic peptide levels at discharge (all-cause mortality HR = 1.29 (1.00-1.66), p = 0.049; hospitalization for HF HR = 1.36 (1.03-1.81), p = 0.033; hospitalization for non-HF HR = 1.38 (1.03-1.86), p = 0.034; composite outcome HR = 1.33 (1.07-1.64), p = 0.01).

CONCLUSIONS

Malnutrition, assessed by the CONUT score, is common among elderly patients admitted for acute HF and is strongly related to increased long-term risk of all-cause death and re-hospitalizations.

Associations between alcohol and cigarette use and type 1 and 2 myocardial infarction among people with HIV

OBJECTIVES

People with HIV have a higher risk of myocardial infarction (MI) than the general population, with a greater proportion of type 2 MI (T2MI) due to oxygen demand-supply mismatch compared with type 1 (T1MI) resulting from atherothrombotic plaque disruption. People living with HIV report a greater prevalence of cigarette and alcohol use than do the general population. Alcohol use and smoking as risk factors for MI by type are not well studied among people living with HIV. We examined longitudinal associations between smoking and alcohol use patterns and MI by type among people living with HIV.

DESIGN AND METHODS

Using longitudinal data from the Centers for AIDS Research Network of Integrated Clinical Systems cohort, we conducted time-updated Cox proportional hazards models to determine the impact of smoking and alcohol consumption on adjudicated T1MI and T2MI.

RESULTS

Among 13 506 people living with HIV, with a median 4 years of follow-up, we observed 177 T1MI and 141 T2MI. Current smoking was associated with a 60% increase in risk of both T1MI and T2MI. In addition, every cigarette smoked per day was associated with a 4% increase in risk of T1MI, with a suggestive, but not significant, 2% increase for T2MI. Cigarette use had a greater impact on T1MI for men than for women and on T2MI for women than for men. Increasing alcohol use was associated with a lower risk of T1MI but not T2MI. Frequency of heavy episodic alcohol use was not associated with MI.

CONCLUSIONS

Our findings reinforce the prioritization of smoking reduction, even without cessation, and cessation among people living with HIV for MI prevention and highlight the different impacts on MI type by gender.

Interdisciplinary Telehealth Team Positively Impacts Difficult-to-Control Hypertension in CKD

Key Points

A collaborative nephrologist–pharmacist telehealth clinic significantly improved difficult-to-control hypertension in patients with CKD. Reduction in systolic BP was achieved without significant and widespread worsening of renal function or change in electrolytes.

Background

Hypertension (HTN) is the most common chronic health condition worldwide and affects patients with CKD at increasing rates as kidney function falls. Uncontrolled BP can have a significant effect on cardiovascular disease, kidney disease progression, and mortality. We implemented an interdisciplinary team to assess the impact a fully virtual management system, on top of usual nephrology care, could have on HTN control among Veterans Administration patients with difficult to manage HTN.

Methods

Patients with difficult-to-control HTN were referred to a collaborative nephrology telemedicine clinic for care by a nephrologist and a clinical pharmacist. BP was managed through telephone visits conducted by the pharmacist every four to 12 weeks. Patients were sent a home BP monitor, provided education about its use, and were instructed to monitor home BP regularly. Those with at least three phone visits who had objective home BP measurements at each visit were included in the pragmatic analysis. Change in systolic BP from baseline was the primary outcome variable.

Results

Of the 55 patients meeting inclusion criteria, a mean reduction of 16±14 mm Hg in systolic BP and 6±7 mm Hg in diastolic BP was shown. In 12±7 months, 44% of patients achieved goal BP (<130/80) and 31% were discharged back to primary care management in an average of 8±5 months with apparent sustained effect.

Conclusions

An interdisciplinary team of a pharmacist and nephrologist using a virtual care model is an effective method for managing difficult-to-control HTN in this pragmatic assessment.

V2 vasopressin receptor mutations: future personalized therapy based on individual molecular biology

The diluting and concentrating function of the kidney plays a crucial role in regulating the water homeostasis of the body. This function is regulated by the antidiuretic hormone, arginine vasopressin through the type 2 vasopressin receptor (V2R), allowing the body to adapt to periods of water load or water restriction. Loss-of-function mutations of the V2R cause X-linked nephrogenic diabetes insipidus (XNDI), which is characterized by polyuria, polydipsia, and hyposthenuria. Gain-of-function mutations of the V2R lead to nephrogenic syndrome of inappropriate antidiuresis disease (NSIAD), which results in hyponatremia. Various mechanisms may be responsible for the impaired receptor functions, and this review provides an overview of recent findings about the potential therapeutic interventions in the light of the current experimental data.

Comparison of CG, CKD-EPI[AS] and CKD-EPI[ASR] equations to estimate glomerular filtration rate and predict mortality in treatment naïve people living with HIV in Zimbabwe

BACKGROUND

Renal impairment in people living with HIV (PWH) in Sub-Saharan Africa is common and associated with increased morbidity and mortality. The ideal equation to estimate glomerular filtration rate (eGFR) in this population remains unclear. That which best predicts clinical risk may be the most appropriate while validation studies are awaited. Here we compare the Cockcroft-Gault (CG), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI[ASR]) and the CKD-EPI equation with the race coefficient removed (CKD-EPI[AS]), in a population of anti-retroviral therapy (ART) naïve PWH in Zimbabwe to assess which equation best predicts mortality.

METHODS

A retrospective cohort study of treatment naïve PWH at the Newlands Clinic in Harare, Zimbabwe was completed. The study included all patients commencing ART between 2007 and 2019. Predictors of mortality were assessed by multivariable logistic regression.

RESULTS

A total of 2991 patients were followed-up for a median of 4.6 years. The cohort was 62.1% female, with 26.1% of patients having at least one comorbidity. The CG equation identified 21.6% of patients as having renal impairment compared with 17.6% with CKD-EPI[AS] and 9.3% with CKD-EPI[ASR]. There was a mortality rate of 9.1% across the study period. The highest mortality risk was seen in those with renal impairment as determined by the CKD-EPI[ASR] equation for both eGFR < 90 and eGFR < 60 with OR 2.97 (95%CI 1.86-4.76) and OR 10.6 (95%CI 3.15-18.04) respectively.

CONCLUSION

In treatment naïve PWH in Zimbabwe, the CKD-EPI[ASR] equation identifies patients at highest risk of mortality when compared to the CKD-EPI[AS] and CG equations.

Association of the triglyceride-glucose index with subclinical left ventricular dysfunction in type 2 diabetes mellitus patients: A retrospective cross-sectional study

AIMS/INTRODUCTION

The triglyceride-glucose (TyG) index is a simple and reliable indicator of insulin resistance, and is associated with the development and poor outcomes of cardiovascular disease. Subclinical left ventricular dysfunction (SLVD) is frequently detected in approximately one-third of diabetes patients, but it has not been established whether the TyG index correlates with SLVD. We carried out this research to evaluate the relationship between the TyG index and SLVD in type 2 diabetes mellitus patients.

MATERIALS AND METHODS

This was a cross-sectional and observational study of 183 type 2 diabetes mellitus inpatients at Nanjing Drum Tower Hospital, Nanjing, China. The TyG index and homeostasis model assessment 2 estimates for insulin resistance (HOMA2-IR) were calculated from biochemical measurements, and speckle-tracking echocardiography was carried out. According to global longitudinal strain (GLS) by echocardiography, participants were categorized into the SLVD (GLS <18%) group or the non-SLVD (GLS ≥18%) group.

RESULTS

In comparison with non-SLVD participants, SLVD participants had higher insulin resistance, as reflected by elevated TyG and HOMA2-IR indices, as well as a higher body mass index, waist circumference and triglyceride level (P < 0.05 for each). When grouped by TyG index tertiles, an elevated TyG index was correlated with other cardiometabolic risk factors, as well as a decrease in GLS. In the multivariate logistic regression analyses, the TyG index was an independent risk factor for SLVD in type 2 diabetes mellitus patients (odds ratio 2.047, 95% confidence interval 1.07-3.914, P  = 0.03), whereas HOMA2-IR was not.

CONCLUSIONS

The TyG index is independently associated with SLVD in type 2 diabetes mellitus patients and is a more reliable indicator of SLVD than HOMA2-IR.

Accuracy of the New Creatinine-based Equations for Estimating Glomerular Filtration Rate in Koreans

Background

New creatinine-based estimated glomerular filtration rate (eGFR) equations, including the 2021 Chronic Kidney Disease Epidemiology Collaboration (2021 CKD-EPI) and European Kidney Function Consortium (EKFC) equations, have been introduced recently. We assessed the performance of the 2021 CKD-EPI and EKFC equations in the Korean population.

Methods

We analyzed 1,654 Korean patients aged ≥18 years who underwent chromium-51-ethylenediamine tetraacetic acid GFR measurements (mGFR). Bias (eGFR-mGFR), root mean square error (RMSE), and proportion of eGFR within 30% of mGFR (P30) of the 2009 CKD-EPI, 2021 CKD-EPI, and EFKC equations were compared. The concordance rate between eGFR and mGFR categories was evaluated. Both eGFR and mGFR categories were classified into six groups: ≥90, 89-60, 59-45, 44-30, 29-15, and <15 mL/min/1.73 m2.

Results

The median bias (mL/min/1.73 m2) was 1.8 for the 2009 CKD-EPI equation, 4.8 for the 2021 CKD-EPI equation, and -0.3 for the EKFC equation. The P30 and RMSE were 78.2% and 17.0 for the 2009 CKD-EPI equation, 75.6% and 17.4 for the 2021 CKD-EPI equation, and 80.0% and 16.7 for the EKFC equation, respectively. The overall GFR category concordance rate between eGFR and mGFR was 63.4% for the 2009 CKD-EPI equation, 60.5% for the 2021 CKD-EPI equation, and 61.0% for the EKFC equation.

Conclusions

Among the three eGFR equations, the EKFC equation had the smallest bias and highest P30 in Koreans. The 2009 CKD-EPI equation had a lower bias than the 2021 CKD-EPI equation.

Detection and analysis of chiral molecules as disease biomarkers

The chirality of small metabolic molecules is important in controlling physiological processes and indicating the health status of humans. Abnormal enantiomeric ratios of chiral molecules in biofluids and tissues occur in many diseases, including cancers and kidney and brain diseases. Thus, chiral small molecules are promising biomarkers for disease diagnosis, prognosis, adverse drug-effect monitoring, pharmacodynamic studies and personalized medicine. However, it remains difficult to achieve cost-effective and reliable analysis of small chiral molecules in clinical procedures, in part owing to their large variety and low concentration. In this Review, we describe current and emerging techniques that detect and quantify small-molecule enantiomers and their biological importance.

Early renal impairment affects hormonal regulators of calcium and bone metabolism and Wnt signalling and the response to vitamin D supplementation in healthy older adults

Bone and renal metabolism are regulated by common factors and there is extensive cross-talk between these organs (the 'renal-bone-axis'). Ageing is associated with physiological changes including reduced bone mass, renal function and tissue sensitivity to regulatory hormones, impacting the renal-bone axis. We aimed to investigate the influence of estimated Glomerular Filtration Rate (eGFR) on plasma concentrations of vitamin D metabolites, Wnt signalling and bone metabolism in a dose ranging vitamin D₃ RCT (12,000 IU, 24,000 IU, 48,000 IU/month for 1 year; n = 379, >70 y) with a baseline eGFR > 30 mL/min/1.73 m². Participants were categorised on basis of eGFR (≥60 or mL/min/1.73 m²) based on 5 commonly used algorithms for eGFR. Differences between eGFR categories were tested with ANCOVA. Before supplementation commenced, a lower eGFR was associated with significantly higher concentrations of c-terminal and intact Fibroblast Growth Factor-23 (cFGF23; iFGF23), intact Parathyroid Hormone (iPTH) and Sclerostin (SOST) and lower Klotho, 1,25-dihydroxy Vitamin D (1,25(OH)₂D) and Dickkopf-related Protein 1 (DKK1) concentrations. Differences between eGFR groups in 25-hydroxy Vitamin D (25(OH)D), 24,25-dihydroxy Vitamin D (24,25(OH)₂D) and iPTH were only detected with eGFR based on Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Modification in Diet for Renal Disease (MDRD-4) algorithms. Differences in Bone Mineral Density and Content (BMD; BMC) and bone turnover markers were detected only with Cockcroft-Gault (CG). Pre- and post- supplementation comparisons showed differences in the response to supplementation by eGFR group. Plasma 25(OH)D, 24,25(OH)₂D, 1,25(OH)₂D and DKK1 increased and iPTH and C-terminal telopeptide (CTX) decreased in both groups. Plasma iFGF23, bone specific alkaline phosphatase (BAP) and Procollagen 1 intact N-terminal Propeptide (PINP) increased and phosphate decreased only in the group with eGFR ≥ 60 mL/min/1.73 m². Findings were largely consistent across all eGFR algorithms. Post-supplementation, cFGF23, iFGF23, iPTH and SOST remained significantly higher in the lower eGFR group. Plasma 1,25(OH)₂D and Klotho did no longer differ between eGFR groups. This was found for all eGFR algorithms, with the exception of iPTH and iFGF23, which were not significantly different with eGFR based on CG. Differences in BMD and BMC were detected with CKD-EPI-creatinine and MDRD-4 but not GC. This study showed that even a moderate decline in eGFR is associated with alterations in vitamin D metabolism, Wnt signalling and bone turnover markers. Renal function influenced the response to vitamin D supplementation. Supplementation increased Vitamin D metabolites in the group with moderate renal impairment to concentrations comparable to those found in the group with normal renal function. However, although CTX decreased, an increase in bone formation markers was not found in the group with eGFR 60 mL/min/1.73 m². In conclusion, vitamin D supplementation had beneficial effects on markers of the renal-bone axis in older people with both normal and impaired renal function.

Update on state-of-the-art for arterial spin labeling (ASL) human perfusion imaging outside of the brain

This review article provides an overview of developments for arterial spin labeling (ASL) perfusion imaging in the body (i.e., outside of the brain). It is part of a series of review/recommendation papers from the International Society for Magnetic Resonance in Medicine (ISMRM) Perfusion Study Group. In this review, we focus on specific challenges and developments tailored for ASL in a variety of body locations. After presenting common challenges, organ-specific reviews of challenges and developments are presented, including kidneys, lungs, heart (myocardium), placenta, eye (retina), liver, pancreas, and muscle, which are regions that have seen the most developments outside of the brain. Summaries and recommendations of acquisition parameters (when appropriate) are provided for each organ. We then explore the possibilities for wider adoption of body ASL based on large standardization efforts, as well as the potential opportunities based on recent advances in high/low-field systems and machine-learning. This review seeks to provide an overview of the current state-of-the-art of ASL for applications in the body, highlighting ongoing challenges and solutions that aim to enable more widespread use of the technique in clinical practice.

The association of lead exposure with blood pressure and hypertension: a mediation analyses of estimated glomerular filtration rate

The link between lead and blood pressure was debatable, and whether it was mediated by renal function was unknown. The purpose was to investigate the relationship between blood lead concentrations and blood pressure and hypertension, as well as the mediating role of estimated glomerular filtration rate (eGFR) in this relationship. Participants aged 18 were recruited from the National Health and Nutrition Examination Survey (1999-2014) and provided with lead and blood pressure data. Multivariate linear and logistic regression, stratification, interaction tests, and a restricted cubic spline curve were used to assess the association of blood lead with systolic/diastolic blood pressure (SBP/DBP) and hypertension, and mediation effect analysis was used to investigate the role of eGFR in this relationship. A total of 20,073 subjects were enrolled, and among them, 9837 (49.01%) were male and 7800 (38.86%) were hypertensive patients. Multivariate linear and logistic regression analysis showed that blood lead levels were significantly associated with SBP (β = 3.14, 95%CI: 2.03, 4.25; P < 0.001), DBP (β = 3.50, 95%CI: 2.69, 4.30; P < 0.001), and hypertension (OR = 1.29, 95%CI: 1.09, 1.52; P = 0.0026). In comparison to the lowest blood lead quartile, the highest lead group was significantly associated with SBP (= 2.55, 95%CI: 1.66, 3.44; P = 0.0001), DBP (= 2.60, 95%CI: 1.95, 3.24; P = 0.0001), and hypertension (OR = 1.26, 95%CI: 1.10, 1.45; P = 0.0007). Mediation analysis showed that the proportion of blood lead mediated for SBP, DBP, and hypertension was 3.56% (95%CI: 0.42%, 7.96%; P = 0.0320), 6.21% (95%CI: 4.02%, 9.32%; P < 0.0001), and 17.39% (95%CI: 9.34%, 42.71%; P < 0.0001), respectively. Adjusted restricted cubic spline curves presented a non-linear correlation of blood lead levels with DBP (P-non-linearity < 0.001), linear with SBP (P-non-linearity = 0.203), and hypertension (P-non-linearity = 0.763). Our findings demonstrated that blood lead levels were non-linear with DBP, but linear with SBP and hypertension, and this relationship was mediated by eGFR.

Sex-Specific Associations of Urinary Metals with Renal Function: a Cross-sectional Study in China

BACKGROUND

Extensive studies have revealed the link between heavy metals and CKD. Compared to single meta-elements, mixture of metals reflect real-life metals exposure scenarios and are of interest. However, the mechanism of action of metal mixture on renal function is unclear.

METHODS

This study aimed to explore the potential relationship between urinary arsenic (As), cadmium (Cd), lead (Pb), manganese (Mn), and chromium (Cr) contents with estimated glomerular filtration rate (eGFR) levels in 2775 participants. The levels of metals in urine were determined by inductively coupled plasma-mass spectrometry. We used linear regression models and the Bayesian kernel machine regression (BKMR) to evaluate the association between metals and eGFR levels.

RESULTS

In linear regression analysis, urinary As (β = 2.723, 95%CI: 0.29, 5.157) and Pb (β = 3.081, 95%CI: 1.725, 4.438) were positively associated with eGFR in the total population. In the BKMR model, a mixture of the five metals had a positive joint effect on eGFR levels, while Pb (PIP = 0.996) contributed the most to eGFR levels. Pb was positively associated with eGFR levels in the total participants and women. As was positively correlated with eGFR levels in women. Pb and eGFR levels were positively correlated when the other metals were set at 25th, 50th, and 75th percentiles.

CONCLUSIONS

To the best of our knowledge, all five metals mixed exposure was positively associated with eGFR. Pb showed more important effects than the other four metals in the mixture, especially in women.

Serum proteome and metabolome uncover novel biomarkers for the assessment of disease activity and diagnosing of systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting thousands of people. There are still no effective biomarkers for SLE diagnosis and disease activity assessment. We performed proteomics and metabolomics analyses of serum from 121 SLE patients and 106 healthy individuals, and identified 90 proteins and 76 metabolites significantly changed. Several apolipoproteins and the metabolite arachidonic acid were significantly associated with disease activity. Apolipoprotein A-IV (APOA4), LysoPC(16:0), punicic acid and stearidonic acid were correlated with renal function. Random forest model using the significantly changed molecules identified 3 proteins including ATRN, THBS1 and SERPINC1, and 5 metabolites including cholesterol, palmitoleoylethanolamide, octadecanamide, palmitamide and linoleoylethanolamide, as potential biomarkers for SLE diagnosis. Those biomarkers were further validated in an independent cohort with high accuracy (AUC = 0.862 and 0.898 for protein and metabolite biomarkers respectively). This unbiased screening has led to the discovery of novel molecules for SLE disease activity assessment and SLE classification.

Hypertension as Cardiovascular Risk Factor in Chronic Kidney Disease

Hypertension is the leading modifiable cause of premature death and hence one of the global targets of World Health Organization for prevention. Hypertension also affects the great majority of patients with chronic kidney disease (CKD). Both hypertension and CKD are intrinsically related, as hypertension is a strong determinant of worse renal and cardiovascular outcomes and renal function decline aggravates hypertension. This bidirectional relationship is well documented by the high prevalence of hypertension across CKD stages and the dual benefits of effective antihypertensive treatments on renal and cardiovascular risk reduction. Achieving an optimal blood pressure (BP) target is mandatory and requires several pharmacological and lifestyle measures. However, it also requires a correct diagnosis based on reliable BP measurements (eg, 24-hour ambulatory BP monitoring, home BP), especially for populations like patients with CKD where reduced or reverse dipping patterns or masked and resistant hypertension are frequent and associated with a poor cardiovascular and renal prognosis. Even after achieving BP targets, which remain debated in CKD, the residual cardiovascular risk remains high. Current antihypertensive options have been enriched with novel agents that enable to lower the existing renal and cardiovascular risks, such as SGLT2 (sodium-glucose cotransporter-2) inhibitors and novel nonsteroidal mineralocorticoid receptor antagonists. Although their beneficial effects may be driven mostly from actions beyond BP control, recent evidence underline potential improvements on abnormal 24-hour BP phenotypes such as nondipping. Other promising novelties are still to come for the management of hypertension in CKD. In the present review, we shall discuss the existing evidence of hypertension as a cardiovascular risk factor in CKD, the importance of identifying hypertension phenotypes among patients with CKD, and the traditional and novel aspects of the management of hypertensives with CKD.