Renal function trajectory over time and adverse clinical outcomes

The Role of Oxidative Stress as a Mechanism in the Pathogenesis of Acute Heart Failure in Acute Kidney Injury

Despite a large amount of research on synchronous and mutually induced kidney and heart damage, the basis of the disease is still not fully clarified. Healthy mitochondria are essential for normal kidney and heart function. Mitochondrial dysfunction occurs when the clearance or process of generation and fragmentation of mitochondria is disturbed. The kidney is the second organ after the heart in terms of the number of mitochondria. Kidney tubules are rich in mitochondria due to the high energy requirements for absorption of large amounts of ultrafiltrate and dissolved substances. The place of action of oxidative stress is the influence on the balance in the production and breakdown of the mitochondrial reactive oxygen species. A more precise determination of the place and role of key factors that play a role in the onset of the disease is necessary for understanding the nature of the onset of the disease and the creation of therapy in the future. This underscores the urgent need for further research. The narrative review integrates results found in previously performed studies that have evaluated oxidative stress participation in cardiorenal syndrome type 3.

Renoprotective Effect of Chrysanthemum coronarium L. Extract on Adenine-Induced Chronic Kidney Disease in Mice

Chronic kidney disease (CKD) gradually leads to loss of renal function and is associated with inflammation and fibrosis. Chrysanthemum coronarium L., a leafy vegetable, possesses various beneficial properties, including anti-oxidative, anti-inflammatory, and antiproliferative effects. In this study, we investigated the renoprotective effect of Chrysanthemum coronarium L. extract (CC) on adenine (AD)-induced CKD in mice. CKD was induced by feeding mice with an AD diet (0.25% w/w) for 4 weeks. Changes in renal function, histopathology, inflammation, and renal interstitial fibrosis were analyzed. The adenine-fed mice were characterized by increased blood urea nitrogen, serum creatinine, and histological changes, including inflammation and fibrosis; however, these changes were significantly restored by treatment with CC. Additionally, CC inhibited the expression of the inflammatory markers, monocyte chemoattractant protein-1, interleukins-6 and -1β, intercellular adhesion molecule-1, and cyclooxygenase 2. Moreover, CC suppressed the expression of the fibrotic markers, type IV collagen, and fibronectin. Furthermore, CC attenuated the expression of profibrotic genes (tumor growth factor-β and α-smooth muscle actin) in AD-induced renal injury mice. Thus, our results suggest that CC has the potential to attenuate AD-induced renal injury and might offer a new option as a renoprotective agent or functional food supplement to manage CKD.

Polyphenol-rich açaí seed extract exhibits reno-protective and anti-fibrotic activities in renal tubular cells and mice with kidney failure

The main goal of this study was to evaluate the reno-protective effects of a phenolic-rich Açaí seed extract (ASE) in mice with kidney failure. Kidney failure was induced chemically with an adenine-rich diet (0.25% w/w for 4 weeks) in male CD1 Swiss mice. Mice were then provided daily with ASE (at a dose of ~ 350 mg/kg/day) in drinking water for 4 weeks. Adenine mice exhibited renal dysfunction evidenced by increased proteinuria, increased uremia, extensive tubular atrophy and kidney fibrosis associated with overexpression of pro-fibrotic genes (collagen 1a1, transforming growth factor β1, TGF-β1) and markers of tubular injury (such as Kidney injury molecule-1, KIM-1). ASE was able to beneficially counteract all these effects. ASE improved oxidative damage and fibrosis by decreasing carbonylated protein and MDA concentrations, as well as collagen deposition in renal tissue. ASE decreased the expression of TGF-β1 gene and the abundance of protein TGF-β1 in kidneys. It further decreased both expression and urinary excretion of tubular injury biomarkers, e.g., KIM-1 and Neutrophil gelatinase-associated lipocalin. CKD ASE-treated mice exhibited higher polyphenol content and total antioxidant capacity compared to control mice. ASE further prevented the expression of profibrotic genes in HK2 human tubular cells exposed to uremic toxins. Taken together, these findings suggest that ASE exerted potent reno-protective and anti-fibrotic effects through its antioxidant activity and the modulation of the TGF-β1 pathway.

Plasma Lead Concentration and Risk of Late Kidney Allograft Failure: Findings From the TransplantLines Biobank and Cohort Studies

RATIONALE & OBJECTIVE

Heavy metals are known to induce kidney damage, and recent studies have linked minor exposures to cadmium and arsenic with increased risk of kidney allograft failure, yet the potential association of lead with late graft failure in kidney transplant recipients (KTRs) remains unknown.

STUDY DESIGN

Prospective cohort study in The Netherlands.

SETTING & PARTICIPANTS

We studied outpatient KTRs (n = 670) with a functioning graft for ≥1 year recruited at a university setting (2008-2011) and followed for a median of 4.9 (interquartile range, 3.4-5.5) years. Additionally, patients with chronic kidney disease (n = 46) enrolled in the ongoing TransplantLines Cohort and Biobank Study (2016-2017, ClinicalTrials.gov identifier NCT03272841) were studied at admission for transplant and at 3, 6, 12, and 24 months after transplant.

EXPOSURE

Plasma lead concentration was log₂-transformed to estimate the association with outcomes per doubling of plasma lead concentration and also considered categorically as tertiles of lead distribution.

OUTCOME

Kidney graft failure (restart of dialysis or repeat transplant) with the competing event of death with a functioning graft.

ANALYTICAL APPROACH

Multivariable-adjusted cause-specific hazards models in which follow-up of KTRs who died with a functioning graft was censored.

RESULTS

Median baseline plasma lead concentration was 0.31 (interquartile range, 0.22-0.45) μg/L among all KTRs. During follow-up, 78 (12%) KTRs experienced graft failure. Higher plasma lead concentration was associated with increased risk of graft failure (hazard ratio, 1.59 [95% CI, 1.14-2.21] per doubling; P = 0.006) independent of age, sex, transplant characteristics, estimated glomerular filtration rate, proteinuria, smoking status, alcohol intake, and plasma concentrations of cadmium and arsenic. These findings remained materially unchanged after additional adjustment for dietary intake and were consistent with those of analyses examining lead categorically. In serial measurements, plasma lead concentration was significantly higher at admission for transplant than at 3 months after transplant (P = 0.001), after which it remained stable over 2 years of follow-up (P = 0.2).

LIMITATIONS

Observational study design.

CONCLUSIONS

Pretransplant plasma lead concentrations, which decrease after transplant, are associated with increased risk of late kidney allograft failure. These findings warrant further studies to evaluate whether preventive or therapeutic interventions to decrease plasma lead concentration may represent novel risk-management strategies to decrease the rate of kidney allograft failure.

Acute kidney injury and risk of cardiovascular outcomes: A nationwide cohort study

BACKGROUND

Acute kidney injury (AKI) has been associated with cardiovascular disease, but this is sparsely studied in non-selected populations and with little attention to the effect in age and renal function. Using nationwide administrative data, we investigated the hypothesis of increased one-year risk of cardiovascular event or death associated with AKI.

METHODS

In a cohort study, we identified all admissions in Denmark between 2008 and 2018. AKI was defined as ≥1.5 times increase from baseline to peak creatinine during admission, or dialysis. We excluded patients with age <50 years, estimated glomerular filtration rate (eGFR) <15ml/min/1.73m², renal transplantation, index-admission due to cardiovascular disease or death during index-admission. The primary outcome was cardiovascular risk within one year from discharge, which was a composite of the secondary outcomes ischemic heart disease, heart failure or stroke. To estimate risks, we applied multiple logistic regression fitted by inverse probability of censoring weighting and stratified estimations by eGFR and age. We adjusted for proteinuria in the subcohort with measurements available.

RESULTS

Among 565,056 hospital admissions, 39,569 (7.0%) cases of AKI were present. In total, 18,642 patients sustained a cardiovascular outcome. AKI was significantly associated with cardiovascular outcome with an adjusted OR [CI] of 1.33 [1.16-1.53], 1.43 [1.33-1.54], 1.23 [1.14-1.34], 1.38 [1.18-1.62] for eGFR ≥90, 60-89, 30-59 and 15-29ml/min/1.73m², respectively. When omitting the outcome heart failure, these results were 1.24 [1.06-1.45], 1.22 [1.11-1.33], 1.05 [0.95-1.16], 1.25 [1.02-1.54]. Results did not change substantially in strata of age groups, in AKI stages and in the subcohort adjusted for proteinuria.

CONCLUSION

Non-selected patients aged 50 years or above with AKI during admission had significantly higher one-year risk of cardiovascular event or death, especially, but not only due to heart failure, independent of age and eGFR.

Acute kidney injury and risk of cardiovascular outcomes: A nationwide cohort study

BACKGROUND

Acute kidney injury (AKI) has been associated with cardiovascular disease, but this is sparsely studied in non-selected populations and with little attention to the effect in age and renal function. Using nationwide administrative data, we investigated the hypothesis of increased one-year risk of cardiovascular event or death associated with AKI.

METHODS

In a cohort study, we identified all admissions in Denmark between 2008 and 2018. AKI was defined as ≥1.5 times increase from baseline to peak creatinine during admission, or dialysis. We excluded patients with age <50 years, estimated glomerular filtration rate (eGFR) <15ml/min/1.73m2, renal transplantation, index-admission due to cardiovascular disease or death during index-admission. The primary outcome was cardiovascular risk within one year from discharge, which was a composite of the secondary outcomes ischemic heart disease, heart failure or stroke. To estimate risks, we applied multiple logistic regression fitted by inverse probability of censoring weighting and stratified estimations by eGFR and age. We adjusted for proteinuria in the subcohort with measurements available.

RESULTS

Among 565,056 hospital admissions, 39,569 (7.0%) cases of AKI were present. In total, 18,642 patients sustained a cardiovascular outcome. AKI was significantly associated with cardiovascular outcome with an adjusted OR [CI] of 1.33 [1.16-1.53], 1.43 [1.33-1.54], 1.23 [1.14-1.34], 1.38 [1.18-1.62] for eGFR ≥90, 60-89, 30-59 and 15-29ml/min/1.73m2, respectively. When omitting the outcome heart failure, these results were 1.24 [1.06-1.45], 1.22 [1.11-1.33], 1.05 [0.95-1.16], 1.25 [1.02-1.54]. Results did not change substantially in strata of age groups, in AKI stages and in the subcohort adjusted for proteinuria.

CONCLUSION

Non-selected patients aged 50 years or above with AKI during admission had significantly higher one-year risk of cardiovascular event or death, especially, but not only due to heart failure, independent of age and eGFR.

Impact of variability in estimated glomerular filtration rate on major clinical outcomes: A nationwide population-based study

BACKGROUND

The estimated glomerular filtration rate (eGFR), commonly estimated using the serum creatinine value, often fluctuates throughout the serial measurement. The clinical significance of GFR variation among the general population with normal renal function has not yet been demonstrated. Thus, we explored the impact of GFR variability on adverse clinical outcomes.

METHODS

A nationwide retrospective cohort study using the Korean National Health Insurance System database was performed. National health screening examinees who underwent creatinine measurement ≥3 times between 2012 and 2016 were considered. Those with eGFR under 60 mL/min/m2 were excluded. The fluctuation of eGFR was represented with variability independent of the mean (VIM) index; which was calculated by the standard deviation divided by the exponent of the regression coefficient of the mean. Then, the risks of myocardial infarction (MI), stroke and death were assessed according to the quartiles of the VIM.

RESULTS

Of total 3,538,500 participants, 0.29% of myocardial infarction (MI), 0.14% of stroke, 0.36% of deaths were observed during the median follow up of 3.27 years. Participants with the highest VIM index, which represents the highest eGFR variability, were significantly associated with an increased risk of MI (hazard ratio [HR]; 1.10, 95% confidence interval [95% CI]; 1.04-1.16), stroke (HR: 1.16; 95% CI 1.09-1.23), and death (HR: 1.18; 95% CI 1.12-1.24). The elevated risk of adverse events was consistent after the multivariate adjustment with potential confounding factors, except the risk of MI (HR 1.06; 95% 1.00-1.06).

CONCLUSIONS

Increased eGFR variability exhibited an association with major clinical outcomes, indicating that monitoring eGFR variability might be a useful parameter for predicting the adverse outcomes.

Plasma cadmium is associated with increased risk of long-term kidney graft failure

The kidney is one of the most sensitive organs to cadmium-induced toxicity, particularly in conditions of long-term oxidative stress. We hypothesized that, in kidney transplant recipients, nephrotoxic exposure to cadmium represents an overlooked hazard for optimal graft function. To test this, we performed a prospective cohort study and included 672 outpatient kidney transplant recipients with a functioning graft of beyond one year. The median plasma cadmium was 58 ng/L. During a median 4.9 years of follow-up, 78 kidney transplant recipients developed graft failure with a significantly different distribution across tertiles of plasma cadmium (13, 26, and 39 events, respectively). Plasma cadmium was associated with an increased risk of graft failure (hazard ratio 1.96, 95% confidence interval 1.56‒2.47 per log₂ ng/L). Similarly, a dose-response relationship was observed over increasing tertiles of plasma cadmium, after adjustments for potential confounders (donor, recipient, transplant and lifestyle characteristics), robust in both competing risk and sensitivity analyses. These findings were also consistent for kidney function decline (graft failure or doubling of serum creatinine). Thus, plasma cadmium is independently associated with an increased risk of long-term kidney graft failure and decline in kidney function. Further studies are needed to investigate whether exposure to cadmium represents an otherwise overlooked modifiable risk factor for adverse long-term graft outcomes in different populations.

Creatinine increase following initiation of antihypertensives is associated with cardiovascular risk: a nationwide cohort study

OBJECTIVE

Abrupt decline in renal function following initiation of renin-angiotensin system inhibitor is associated with increased risk of cardiovascular disease, but studies of other antihypertensive drugs are sparse. We investigated the risk of cardiovascular event associated with increased plasma creatinine after initiating first-line antihypertensive treatment.

METHODS

In a nationwide cohort study, we identified adult Danish primary care patients initiating either renin-angiotensin system inhibitor, calcium channel blocker or thiazide, between 2008 and mid-2018. Patients with prior end-stage renal disease, renal transplantation, or cardiovascular disease were excluded. Percentual plasma creatinine increase was calculated between the nearest creatinine measurement up to 1 year before redeeming the prescription (baseline), and the nearest measurement 90 days or less after (index). Multiple logistic regression and restricted cubic splines were applied to estimate the 6-month absolute risk of cardiovascular event (ischemic heart disease, heart failure or stroke) associated with this creatinine increase.

RESULTS

We included 20 789 patients. Within the first 6 months of follow-up, 283 (1.4%) cardiovascular events and 93 (0.4%) all-cause deaths were registered. With a creatinine increase of 0 and 30%, 6-month absolute risk [CI] of cardiovascular event was 1.4% [1.1-1.9] and 3.5% [2.4-5.2], respectively (in men aged 50-79 years with estimated glomerular filtration rate at least 60 ml/min per 1.73 m and no diabetes). Higher age and reduced renal function, but not the type of antihypertensive treatment, were associated with higher cardiovascular risk.

CONCLUSION

In primary care, patients initiating first-line antihypertensive treatment, an increase in plasma creatinine above 30% was associated with increased absolute 6-month risk of cardiovascular event.

Change of Kidney Function Is Associated With All-Cause Mortality and Cardiovascular Diseases: Results From the Kailuan Study

Background

Current evaluation about the relationship of sequential change in estimated glomerular filtration rate (eGFR) and clinical outcomes are still inconsistent. We aimed to investigate the association between the change in kidney function over time and the risk of all‐cause mortality and cardiovascular disease.

Methods and Results

This prospective cohort including 37 691 participants aged ≥45 years used data from the Kailuan Health Registry. The relationship of the annual percentage and absolute change in eGFR and outcomes were analyzed with Cox proportional regression. The participants were stratified according to the quintiles distribution of the percentage annual change in eGFR (Q1–Q5). After adjusting for baseline covariates including initial eGFR, participants with annual eGFR decline were at significantly greater risk for all‐cause mortality (Q1: hazard ratio, 1.22 [95% confidence interval, 1.04–1.43]; Q2: 1.19 [1.01–1.40]) than noted for patients in Q3. Cardiovascular disease risk was also significantly higher in participants with annual eGFR decline (Q1 and Q2). No significantly increased risk of adverse outcomes was noted for patients with annual eGFR increased groups (Q4 and Q5). When considering the absolute eGFR annual change rate (no/mild/rapid decline), we obtained similar results in chronic kidney disease participants, whereas non–chronic kidney disease participants had less pronounced association of eGFR decline with cardiovascular disease, though not with mortality.

Conclusions

A decline in eGFR over time is associated with higher risk for all‐cause mortality and cardiovascular disease independent of initial eGFR and other known risk factors at baseline. Our data support the serial evaluation of change in kidney function as a better prognostic indicator than single eGFR assessments.

Creatinine- and cystatin C-based estimated glomerular filtration rate slopes for the prediction of kidney outcome: a comparative retrospective study

BACKGROUND

Many studies have evaluated the usefulness of creatinine- (eGFRcr) and cystatin C-based estimated glomerular filtration rate (eGFRcys) at specific time points in predicting renal outcome. This study compared the performance of both eGFR changing slopes in identifying patients at high risk of end-stage renal disease (ESRD).

METHODS

From 2012 to 2017, patients with more than three simultaneous measurements of serum creatinine and cystatin C for 1 year were identified. Rapid progression was defined as eGFR slope < - 5 mL/min/1.73 m²/year. The primary outcome was progression to ESRD.

RESULTS

Overall, 1323 patients were included. The baseline eGFRcr and eGFRcys were 39 (27-48) and 38 (27-50) mL/min/1.73 m², respectively. Over 2.9 years (range, 2.0-3.8 years) of follow-up, 134 subjects (10%) progressed to ESRD. Both the eGFRcr and eGFRcys slopes were associated with a higher risk of ESRD, independently of baseline eGFR (hazard ratio [HR] = 0.986 [0.982-0.991] and HR = 0.988 [0.983-0.993], respectively; all p <  0.001). The creatinine- and cystatin C-based rapid progressions were associated with increased risk of ESRD (HR = 2.22 [1.57-3.13], HR = 2.03 [1.44-2.86], respectively; all p <  0.001). In the subgroup analyses, the rapid progression group, defined on the basis of creatinine levels (n = 503), showed no association between the eGFRcys slope and ESRD risk (p = 0.31), whereas the eGFRcr slope contributed to further discriminating higher ESRD risk in the subjects with rapid progression based on eGFRcys slopes (n = 463; p = 0.003).

CONCLUSIONS

Both eGFR slopes were associated with future ESRD risk. The eGFRcr slope was comparable with the eGFRcys slope in predicting kidney outcome.

Competing risk of death and end-stage renal disease in incident chronic kidney disease (stages 3 to 5): the EPIRAN community-based study

BACKGROUND

Although chronic kidney disease (CKD) affects a growing number of people, epidemiologic data on incident CKD in the general population are scarce. Screening strategies to increase early CKD detection have been developed.

METHODS

From a community-based sample of 4,409 individuals residing in a well-defined geographical area, we determined the number of patients having a first serum creatinine value ≥1.7 mg/dL and present for at least 3 months that allowed us to calculate an annual incidence rate of CKD (stages 3 to 5). CKD (stages 3 to 5) was defined by estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. We also described the primary care, outcomes and risk factors associated with outcomes using competing risks analyses for these CKD patients.

RESULTS

A total of 631 incident CKD patients (stages 3 to 5) were followed-up until the occurrence of death and dialysis initiation for more than 3 years. The annual incidence rate of CKD (stages 3 to 5) was estimated at 977.7 per million inhabitants. Analyses were performed on 514 patients with available medical data. During the study, 155 patients (30.2 %) were referred to a nephrologist, 193 (37.5 %) died and 58 (11.3 %) reached end-stage renal disease and initiated dialysis. A total of 139 patients (27.6 %) had a fast decline of their renal function, 92 (18.3 %) a moderate decline and the 272 remaining patients had a physiological decline (21.1 %) or a small improvement of their renal function (33.0 %). Predictors of death found in both Cox and Fine-Gray multivariable regression models included age at diagnosis, anemia, active neoplasia and chronic heart failure, but not a low glomerular filtration rate (GFR). Age at diagnosis, anemia and a low GFR were independently associated with dialysis initiation in Cox model, but anemia was not found to be a risk factor for dialysis initiation in Fine-Gray model.

CONCLUSIONS

This large cohort study provided useful epidemiological data on incident CKD (stages 3 to 5) and stressed the need to improve the hands-on implementation of clinical practice guidelines for the evaluation and the management of CKD in primary care.