CKD Prevalence Varies across the European General Population

How Do I Manage Hypertension in Patients with Advanced Chronic Kidney Disease Not on Dialysis? Perspectives from Clinical Practice

In the general population, the prevalence of moderate and severe chronic kidney disease (CKD) is usually below 5% but this figure is often higher in specific groups of patients such as those with type 2 diabetes. Patients with advanced CKD (CKD stage 3b and 4) are at high or very high cardiovascular risk, and their risk of progressing towards end-stage kidney disease (CKD stage 5) and the need of renal replacement therapy are elevated. Hypertension is a major cause of poor cardiovascular and renal outcomes in severe CKD. Therefore, an adequate control of blood pressure (BP) is mandatory. However, normalizing BP is often challenging in these patients because the clinical management of hypertension in advanced CKD is not well defined and rarely supported by large randomized controlled trials. In the present review, we discuss the characteristics of hypertension in advanced CKD, excluding dialysis, and its management integrating data from recent clinical studies and a pragmatic approach enriched by a long-standing clinical experience.

Cortical perfusion as assessed with contrast-enhanced ultrasound is lower in patients with chronic kidney disease than in healthy subjects but increases under low salt conditions

Background

Disturbances in renal microcirculation play an important role in the pathophysiology of chronic kidney disease (CKD), but the lack of easy accessible techniques hampers our understanding of the regulation of the renal microcirculation in humans. We assessed whether contrast-enhanced ultrasound (CEUS) can identify differences in cortical perfusion and alterations induced by different dietary salt intakes in CKD patients and controls.

Methods

Participants underwent CEUS twice: once after 5 days of high-salt (HS) intake, and again after 5 days of low salt (LS) diet. Sonovue® (0.015 mL/kg/min) was perfused as contrast agent and four consecutive destruction–reperfusion sequences were analysed per visit. The primary outcome measure was the (change in) mean perfusion index (PI) of the renal cortex.

Results

Forty healthy volunteers (mean age ± standard deviation 50 ± 8 years) and 18 CKD Stages 2–4 patients [aged 55 ± 11 years, estimated glomerular filtration rate (eGFR) 54 ± 28 mL/min/1.73 m2] were included and underwent CEUS without side effects. Under HS conditions, cortical PI was significantly lower in CKD patients [1618 ± 1352 versus 3176 ± 2278 arbitrary units (a.u) in controls, P = 0.034]. Under LS, renal PI increased in CKD patients (with +1098 to 2716 ± 1540 a.u., P = 0.048), whereas PI remained stable in controls. In the continuous analysis, PI correlated with eGFR (Spearman’s r = 0.54, P = 0.005) but not with age, sex, blood pressure or aldosterone levels.

Conclusions

CEUS identified important reductions in cortical micro-perfusion in patients with moderate CKD. Lowering salt intake increased perfusion in CKD patients, but not in controls, underlining the benefits of an LS diet in CKD patients. Whether a low PI is an early sign of kidney damage and predicts renal function decline needs further study.

Supplemented ERA-EDTA Registry data evaluated the frequency of dialysis, kidney transplantation, and comprehensive conservative management for patients with kidney failure in Europe

The aims of this study were to determine the frequency of dialysis and kidney transplantation and to estimate the regularity of comprehensive conservative management (CCM) for patients with kidney failure in Europe. This study uses data from the ERA-EDTA Registry. Additionally, our study included supplemental data from Armenia, Germany, Hungary, Ireland, Kosovo, Luxembourg, Malta, Moldova, Montenegro, Slovenia and additional data from Israel, Italy, Slovakia using other information sources. Through an online survey, responding nephrologists estimated the frequency of CCM (i.e. planned holistic care instead of kidney replacement therapy) in 33 countries. In 2016, the overall incidence of replacement therapy for kidney failure was 132 per million population (pmp), varying from 29 (Ukraine) to 251 pmp (Greece). On 31 December 2016, the overall prevalence of kidney replacement therapy was 985 pmp, ranging from 188 (Ukraine) to 1906 pmp (Portugal). The prevalence of peritoneal dialysis (114 pmp) and home hemodialysis (28 pmp) was highest in Cyprus and Denmark respectively. The kidney transplantation rate was nearly zero in some countries and highest in Spain (64 pmp). In 28 countries with five or more responding nephrologists, the median percentage of candidates for kidney replacement therapy who were offered CCM in 2018 varied between none (Slovakia and Slovenia) and 20% (Finland) whereas the median prevalence of CCM varied between none (Slovenia) and 15% (Hungary). Thus, the substantial differences across Europe in the frequency of kidney replacement therapy and CCM indicate the need for improvement in access to various treatment options for patients with kidney failure.

Protective Effects of Eicosapentaenoic Acid on the Glomerular Endothelium via Inhibition of EndMT in Diabetes

Diabetes-induced endothelial pathologies are hypothesized to lead to the progression of diabetic kidney disease (DKD). The endothelial to mesenchymal transition (EndMT) possibly induces fibrosis, leading to glomerulosclerosis in the kidney. Furthermore, this could lead to albuminuria in diabetic nephropathy due to glomerular endothelial dysfunction. Eicosapentaenoic acid (EPA), purified from fish oil, decreases inflammatory cytokine levels in glomerulonephritis. Here, we aimed at finding whether ethyl eicosapentaenoate (EPA-E) exerts renal protective effects via EndMT inhibition. To find out whether EPA inhibits EndMT in vitro, the changes in CD31 expression were studied in cultured mouse endothelial cells. The addition of the conditioned medium from the adipocyte culture significantly decreased the protein levels of CD31, while the addition of EPA-E partially reversed this inhibition. Further, EndMT inhibition by EPA-E treatment might occur via the inhibition of the protein kinase Cβ (PKCβ)/transforming growth factor-β (TGF-β)/plasminogen activator inhibitor-1 (PAI-1) signaling and not via microRNAs. Streptozotocin-induced diabetic mice fed a high-fat diet (60% from fat) exhibited mesangial expansion and albuminuria. Induction of EPA-E ameliorated the mesangial expansion and decreased albuminuria without affecting blood pressure, triglyceride and free fatty acid levels, and intraperitoneal glucose. These findings suggest that EPA-E exerts renal protective effects on endothelial cells, by normalizing EndMT followed by the PKCβ/TGF-β/PAI-1 signaling. Thus, EPA-E has the potential for imparting renal protection by regulating EndMT in DKD.

Chronic Kidney Disease: Current State of the Problem

Chronic kidney disease (CKD) is characterized by increasing prevalence, catalyzing properties in relation to cardiovascular and general mortality, and, in most cases, is asymptomatic, which means late diagnostic verifiability. The global average prevalence of CKD is 13.4%, and CKD C3-5 is 10.6%. The main causes of CKD C5 are diabetes mellitus (DM, 46.9%), hypertension (28.8%) and to a lesser extent, glomerulonephritis (7.1%) and polycystic diseases (2.8%), while other causes account for a total of 14.4%. Despite the simple diagnosis of CKD, one of the key problems of modern therapeutic and pediatric clinics is its low detection rate at the early stages, which, according to some data, reaches 96.6%. This review provides data on the criteria for the diagnosis of CKD, as well as more detailed consideration of the course of CKD in patients with DM, hypertension, and heart failure. Attention is paid to the medicinal origin of CKD, as well as to the development of anxiety and depressive disorders in CKD. General issues of treatment of patients with CKD are considered in detail. Lifestyle changes are an important part of the fight against the development and progression of CKD. Currently, Smoking, alcohol, and physical inactivity have been shown to have a harmful effect on the risk of developing and progressing CKD. Diet plays a certain preventive role. The main drugs with nephroprotective properties are angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists. Both classes of drugs are effective in proteinuric forms of nephropathies and in combination/association of CKD with diabetes or hypertension. The review also provides data on the nephroprotective properties of mineralocorticoid receptor antagonists, endothelin receptor antagonists, and sodium-glucose co-transporter-2 inhibitors. Given the high importance of identifying and effectively treating patients with CKD, it is necessary to focus on early detection of CKD, especially in high-risk groups. It is necessary to raise public awareness by creating and implementing programs for primary prevention of CKD, as well as awareness of patients, motivating them to follow the doctor's recommendations for a long time, including as part of the implementation of a non-drug strategy to combat CKD. It is important to use the full range of methods of drug therapy for CKD, including measures of universal nephroprotection. It should be remembered that the cost of late diagnosis of CKD is a reduction in life expectancy, primarily due to high rates of cardiovascular mortality, disability, and high-cost medication and kidney replacement therapy.

Familial Aggregation of CKD and Heritability of Kidney Biomarkers in the General Population: The Lifelines Cohort Study

RATIONALE & OBJECTIVE

Chronic kidney disease (CKD) has a heritable component. We aimed to quantify familial aggregation of CKD in the general population and assess the extent to which kidney traits could be explained by genetic and environmental factors.

STUDY DESIGN

Cross-sectional 3-generation family study.

SETTING & PARTICIPANTS

Data were collected at entry into the Lifelines Cohort Study from a sample of the general population of the northern Netherlands, composed predominantly of individuals of European ancestry.

EXPOSURE

Family history of CKD.

OUTCOMES

The primary outcome was CKD, defined as estimated glomerular filtration rate (eGFR)<60mL/min/1.73m², where GFR was estimated using the CKD Epidemiology Collaboration creatinine equation. Among a subsample for which urinary albumin concentration was available (n=59,943), urinary albumin excretion was expressed as the rate of urinary albumin excretion (UAE) per 24 hours or urinary albumin-creatinine ratio (UACR).

ANALYTICAL APPROACH

Familial aggregation of CKD was assessed by calculating the recurrence risk ratio (RRR), using adapted Cox proportional hazards models. Heritability of continuous kidney-related traits was estimated using linear mixed models and defined as the ratio of the additive genetic variance to total phenotypic variance. All models were adjusted for age, sex, and known risk factors for kidney disease.

RESULTS

Among 155,911 participants with available eGFR data, the prevalence of CKD was 1.19% (1,862 cases per 155,911). The risk of CKD in those with an affected first-degree relative was 3 timeshigher than the risk in the total sample (RRR, 3.04 [95% CI, 2.26-4.09). In those with an affected spouse, risk of CKD was also higher (RRR, 1.56 [95% CI, 1.20-1.96]), indicative of shared environmental factors and/or assortative mating. Heritability estimates of eGFR, UAE, and UACR were 44%, 20%, and 18%, respectively. For serum urea, creatinine, and uric acid, estimates were 31%, 37%, and 48%, respectively, whereas estimates for serum electrolytes ranged from 22% to 28%.

LIMITATIONS

Use of estimated rather than measured GFR. UAE data only available in a subsample.

CONCLUSIONS

In this large population-based family study, a positive family history was strongly associated with increased risk of CKD. We observed moderate to high heritability of kidney traits and related biomarkers. These results indicate an important role of genetic factors in CKD risk.

Review of the structural and functional brain changes associated with chronic kidney disease

Chronic kidney disease (CKD) leads to profound metabolic and hemodynamic changes, which damage other organs, such as heart and brain. The brain abnormalities and cognitive deficit progress with the severity of the CKD and are mostly expressed among hemodialysis patients. They have great socio-economic impact. In this review, we present the current knowledge of involved mechanisms.

Micronucleus frequency in chronic kidney disease patients: A review

BACKGROUND

Chronic kidney disease (CKD) is defined as a gradual loss of renal function progressing from very mild damage, with no obvious symptoms in stage one, to complete kidney failure in stage five, which ultimately requires kidney replacement therapy by organ transplantation or dialysis. Cancer incidence and other health problems, mainly diabetes and hypertension, are elevated in CKD, ultimately leading to elevated mortality.

METHODS

A literature search on the induction of micronuclei (MN) as endpoint for genomic damage in white blood cells and buccal mucosa cells of CKD patients was conducted. Possible associations with disease stage, treatment modalities, and vitamin or antioxidant supplementations were analyzed.

RESULTS

In total, 26 studies were enclosed in the data analysis. Patient groups in the predialysis or hemodialysis state of the disease exhibit higher levels of genomic damage, measured as micronucleus frequency in peripheral blood lymphocytes and buccal mucosa cells, than healthy control groups. Genomic damage seems to increase with the disease stage during the predialysis phase. The association with dialysis regimens or with years on dialysis is less clear, but there are indications that efficient removal of uremic toxins is beneficial. Patients with CKD receive a variety of medications, some of which could modulate genomic damage levels and thus contribute to the observed heterogeneity. In addition, supplementation with vitamins or antioxidants may in some cases lower the genomic damage. Meta-Analysis confirmed the high and significant levels of genomic damage present in CKD patients compared to matched healthy controls.

CONCLUSION

Genomic damage, as measured by the MN frequency, is elevated in CKD patients. Different strategies, including supplementation with antioxidants and optimizing dialysis processes, can reduce the levels of genomic damage and the different associated pathologies. Whether MN frequency can in the future also be used to assist in certain therapeutic decisions in CKD will have to be investigated further in larger studies.

Worldwide Disparity in the Relation Between CKD Prevalence and Kidney Failure Risk

Introduction

The incidence of kidney replacement therapy (KRT) for kidney failure varies internationally much more than chronic kidney disease (CKD) prevalence. This ecologic study investigated the relation of CKD prevalence to KRT and mortality risks by world region.

Methods

We used data from Global Burden of Disease and KRT registries worldwide with linear models to estimate the percentages of variance in KRT incidence and all-cause mortality explained by age-adjusted prevalence of CKD stages 3 to 5, overall and by gender, in 61 countries classified in 3 regions: high income (n = 28), Eastern and Central Europe (n = 15), and other (n = 18).

Results

The incidence of KRT ranged from 89 to 378 per million population in high-income regions, 32 to 222 per million population in Central and Eastern Europe, and 22 to 493 per million population in the other region; age-adjusted CKD prevalence ranged from 5.5% to 10.4%, 7.6% to 13.7%, and 7.4% to 13.1%, respectively. The relation between these indicators was positive in high-income countries, negative in Central and Eastern Europe, and null in the other region. Age-adjusted CKD prevalence explained 40% of the variance in KRT incidence (P < 0.001) in high-income countries. The explained variance of age-adjusted mortality was close to 0 in high-income countries and positive at 19% (P = 0.10) in Central and Eastern Europe and at 11% (P = 0.17) in the other region. Results were consistent by gender.

Conclusion

This study raises awareness on the significant part of the gaps in KRT incidence across countries not explained by the number of individuals with CKD, even in high-income countries where access to KRT is not limited.

The Crosstalk between Calcium Ions and Aldosterone Contributes to Inflammation, Apoptosis, and Calcification of VSMC via the AIF-1/NF-κB Pathway in Uremia

Vascular calcification is a major complication of maintenance hemodialysis patients. Studies have confirmed that calcification mainly occurs in the vascular smooth muscle cells (VSMC) of the vascular media. However, the exact pathogenesis of VSMC calcification is still unknown. This study shows that the crosstalk between calcium and aldosterone via the allograft inflammatory factor 1 (AIF-1) pathway contributes to calcium homeostasis and VSMC calcification, which is a novel mechanism of vascular calcification in uremia. In vivo results showed that the level of aldosterone and inflammatory factors increased in calcified arteries, whereas no significant changes were observed in peripheral blood. However, the expression of inflammatory factors markedly increased in the peripheral blood of uremic rats without aortic calcification and gradually returned to normal levels with aggravation of aortic calcification. In vitro results showed that there was an interaction between calcium ions and aldosterone in macrophages or VSMC. Calcium induced aldosterone synthesis, and in turn, aldosterone also triggered intracellular calcium content upregulation in macrophages or VSMC. Furthermore, activated macrophages induced inflammation, apoptosis, and calcification of VSMC. Activated VSMC also imparted a similar effect on untreated VSMC. Finally, AIF-1 enhanced aldosterone- or calcium-induced VSMC calcification, and NF-κB inhibitors inhibited the effect of AIF-1 on VSMC. These in vivo and in vitro results suggest that the crosstalk between calcium ions and aldosterone plays an important role in VSMC calcification in uremia via the AIF-1/NF-κB pathway. Local calcified VSMC induced the same pathological process in surrounding VSMC, thereby contributing to calcium homeostasis and accelerating vascular calcification.

Chronic kidney disease in Spain: analysis of patient characteristics, incidence and direct medical costs (2011-2017)

OBJECTIVES

To review the characteristics of patients with chronic kidney disease (CKD) who attended primary and specialized care centers in Spain, and to analyze patients' use of medical resources and direct medical costs of specialized care.

METHODS

Records of patients with CKD admitted to primary and specialized healthcare centers in Spain between 2011 and 2017 from two national discharge databases were analyzed in a retrospective multicenter observational study. Records were classified into one-to-five CKD stages plus a 5b stage, indicating end-stage renal disease.

RESULTS

Most of the patients registered in hospital settings were in stage 5. Registered secondary conditions included hypertensive chronic kidney, diabetes, anemia, hypercholesterolemia, and hypertension. The number of cases registered in primary care settings increased over time, whereas in specialized care centers incidence decreased; hospital incidence of CKD in 2017 was 10.72 per 10,000 persons. Mean in-hospital mortality was 5.90%, which remained stable during the study period. Mortality was associated with respiratory and heart failure. Mean length of hospital stay was 8.19 days, decreasing over the study period, whilst increasing with CKD progression. Mean annual direct medical cost of specialized care was €10,436 per patient. Complications of a transplant and bacterial infections were responsible for major increases in medical costs, that otherwise decreased over the study period.

CONCLUSIONS

The costs of specialized care decreased with the length of hospital stay reduction. Cardiovascular risk factors were crucial in in-hospital mortality. This study provides population-based data to assist decision-makers at the national level and to contribute to worldwide evaluations and disease surveillance.

Sexual Dimorphism of Coronavirus 19 Morbidity and Lethality

The recent coronavirus disease 2019 (COVID-19) pandemic showed a different severity in the disease between males and females. Men have been becoming severely ill at a higher rate than women. These data along with an age-dependent disease susceptibility and mortality in the elderly suggest that sex hormones are the main factors in determining the clinical course of the infection. The differences in aging males versus females and the role of sex hormones in key phenotypes of COVID-19 infection are described in this review. Recommendations based on a dimorphic approach for males and females suggest a sex-specific management the disease.

Statin treatment reduces the risk of death among elderly frail patients: evidence from a large population-based cohort

AIMS

To assess the protective effect of statins in a large and unselected cohort of frail elderly subjects.

METHODS AND RESULTS

The 460 460 Lombardy residents (Italy), aged ≥65 years, who received ≥3 consecutive prescriptions of a statin during 2011-2012 were identified. A case-control study was performed, the cases being the cohort members who died during 2011-2018. Logistic regression was used to model the outcome risk associated with statin adherence. Adherence to drug therapy was measured by the proportion of the follow-up covered by prescriptions. The analysis was stratified according to four clinical categories (good, medium, poor, and very poor clinical status), based on different life expectancies, as assessed by a prognostic score which had been found to sensitively predict the risk of death. The 7-year death probability increased from 11% (good) to 52% (very poor clinical status). In each clinical status, there was a significant reduction of all-cause mortality as adherence to statin treatment increased. The reduction in the adjusted risk of mortality from the lowest to the highest adherence level was greatest among patients with a good clinical status (-56%) and progressively less among other cohort members, i.e. -48%, -44% and -47% in medium, poor, and very poor groups, respectively. Similar findings were obtained for the risk of cardiovascular mortality.

CONCLUSION

In a real-life setting, adherence to statin treatment reduced the death risk also in frail elderly patients. However, in these patients, the benefit of statin treatment may be lower than in those in good clinical conditions.

Contribution of cystatin C- and creatinine-based definitions of chronic kidney disease to cardiovascular risk assessment in 20 population-based and 3 disease cohorts: the BiomarCaRE project

BACKGROUND

Chronic kidney disease has emerged as a strong cardiovascular risk factor, and in many current guidelines, it is already considered as a coronary heart disease (CHD) equivalent. Routinely, creatinine has been used as the main marker of renal function, but recently, cystatin C emerged as a more promising marker. The aim of this study was to assess the comparative cardiovascular and mortality risk of chronic kidney disease (CKD) using cystatin C-based and creatinine-based equations of the estimated glomerular filtration rate (eGFR) in participants of population-based and disease cohorts.

METHODS

The present study has been conducted within the BiomarCaRE project, with harmonized data from 20 population-based cohorts (n = 76,954) from 6 European countries and 3 cardiovascular disease (CVD) cohorts (n = 4982) from Germany. Cox proportional hazards models were used to assess hazard ratios (HRs) for the various CKD definitions with adverse outcomes and mortality after adjustment for the Systematic COronary Risk Evaluation (SCORE) variables and study center. Main outcome measures were cardiovascular diseases, cardiovascular death, and all-cause mortality.

RESULTS

The overall prevalence of CKD stage 3-5 by creatinine- and cystatin C-based eGFR, respectively, was 3.3% and 7.4% in the population-based cohorts and 13.9% and 14.4% in the disease cohorts. CKD was an important independent risk factor for subsequent CVD events and mortality. For example, in the population-based cohorts, the HR for CVD mortality was 1.72 (95% CI 1.53 to 1.92) with creatinine-based CKD and it was 2.14 (95% CI 1.90 to 2.40) based on cystatin-based CKD compared to participants without CKD. In general, the HRs were higher for cystatin C-based CKD compared to creatinine-based CKD, for all three outcomes and risk increased clearly below the conventional threshold for CKD, also in older adults. Net reclassification indices were larger for a cystatin-C based CKD definition. Differences in HRs (between the two CKD measures) in the disease cohorts were less pronounced than in the population-based cohorts.

CONCLUSION

CKD is an important risk factor for subsequent CVD events and total mortality. However, point estimates of creatinine- and cystatin C-based CKD differed considerably between low- and high-risk populations. Especially in low-risk settings, the use of cystatin C-based CKD may result in more accurate risk estimates and have better prognostic value.

How to interpret an estimated glomerular filtration rate (eGFR) in 2020?

Chronic kidney disease (CKD) is defined as abnormalities of kidney structure and function proven to be chronic. The prevalence of CKD in the majority of studies is 10%-16%, neglecting the chronicity character. Jonsson et al., in a nationwide study defining CKD adhering strictly to Kidney Disease: Improving Global Outcomes (KDIGO) criteria, found a clearly lower prevalence of CKD (6%). This indicated that to obtain a correct CKD prevalence, one should start by correctly applying the KDIGO guidelines.

Mid-term survival of patients with chronic kidney disease after extracorporeal membrane oxygenation

OBJECTIVES

Chronic kidney disease (CKD) impairs the elimination of fluids, electrolytes and metabolic wastes, which can affect the outcomes of extracorporeal membrane oxygenation (ECMO) treatment. This study aimed to elucidate the impact of CKD on in-hospital mortality and mid-term survival of adult patients who received ECMO treatment.

METHODS

Patients who received first-time ECMO treatment between 1 January 2003 and 31 December 2013 were included. Those with CKD were identified and matched to patients without CKD using a 1:2 ratio and were followed for 3 years. The study outcomes included in-hospital outcomes and the 3-year mortality rate. A subgroup analysis was conducted by comparing the dialytic patients with the non-dialytic CKD patients.

RESULTS

The study comprised 1008 CKD patients and 2016 non-CKD patients after propensity score matching. The CKD patients had higher in-hospital mortality rates [69.5% vs 62.2%; adjusted odds ratio 1.41; 95% confidence interval (CI) 1.15-1.72] than the non-CKD patients. The 3-year mortality rate was 80.4% in the CKD group and 68% in the non-CKD group (adjusted hazard ratio 1.17; 95% CI 1.06-1.28). The subgroup analysis showed that the 3-year mortality rates were 84.5% and 78.4% in the dialytic and non-dialytic patients, respectively. No difference in the 3-year mortality rate was noted between the 2 CKD subgroups (P = 0.111).

CONCLUSIONS

CKD was associated with increased risks of in-hospital and mid-term mortalities in patients who received ECMO treatment. Furthermore, no difference in survival was observed between the patients with end-stage renal disease and non-dialytic CKD patients.

The Management of Non-Dialysis-Dependent Chronic Kidney Disease in Primary Care

BACKGROUND

Approximately 10% of adults in Germany have chronic kidney disease (CKD). The prevalence of CKD among patients being cared for by general practitioners is approximately 30%, and its prevalence in nursing homes is over 50%. An S3 guideline has been developed for the management of CKD in primary care.

METHODS

The guideline is based on publications retrieved by a systematic search of the literature for international guidelines published in the period 2013-2017, and additional searches on specific questions. It was created by the German College of General Practitioners and Family Physicians (Deutsche Gesellschaft für Allgemeinmedizin und Familienmedizin, DEGAM) and consented with the German Societies of Nephrology and Internal Medicine (DGfN, DGIM) and patient representation.

RESULTS

Upon the initial diagnosis of CKD (glomerular filtration rate [GFR] <60 mL/ min), the patient's blood pressure and urinary albumin-to-creatinine ratio (ACR) should be measured, and the urine should be examined for hematuria. Monitoring intervals are determined on an individual basis depending on the stage of disease and the patient's general state of health and personal preferences. Nephrological consultation should be obtained if the GFR is less than 30 mL/min, if CKD is initially diagnosed (GFR 30-59 mL/min) in the presence of persistent hematuria without any urological explanation or of albinuria in stage A2 or higher, if the patient has refractory hypertension requiring three or more antihypertensive drugs, or if the renal disease is rapidly progressive. The threshold for referring a patient should be kept low for persons under age 50; persons over age 70 should be referred only if warranted in consideration of their comorbidities and individual health goals.

CONCLUSION

The main elements of the treatment of CKD are the treatment of hypertension and diabetes and the modification of lifestyle factors. An innovation from the primary care practioner's perspective is the assessment of albuminuria with the albumin-to-creatinine ratio.

Ticagrelor monotherapy in patients with concomitant diabetes mellitus and chronic kidney disease: a post hoc analysis of the GLOBAL LEADERS trial

Background

Patients with both diabetes mellitus (DM) and chronic kidney disease (CKD) are a subpopulation characterized by ultrahigh ischemic and bleeding risk after percutaneous coronary intervention. There are limited data on the impact of ticagrelor monotherapy among these patients.

Methods

In this post hoc analysis of the GLOBAL-LEADERS trial, the treatment effects of the experimental (one-month dual-antiplatelet therapy [DAPT] followed by 23-month ticagrelor monotherapy) versus the reference regimen (12-month DAPT followed by 12-month aspirin alone) were analyzed according to DM/CKD status. The primary endpoint was a composite endpoint of all-cause death or new Q-wave myocardial infarction at 2-years. The patient-oriented composite endpoint (POCE) was defined as the composite of all-cause death, any stroke, site-reported MI and any revascularization, whereas net adverse clinical events (NACE) combined POCE with BARC type 3 or 5 bleeding events.

Results

At 2 years, the DM + /CKD + patients had significantly higher incidences of the primary endpoint (9.5% versus 3.1%, adjusted HR 2.16; 95% CI [1.66–2.80], p < 0.001), BARC type 3 or 5 bleeding events, stroke, site-reported myocardial infraction, all revascularization, POCE, and NACE, compared with the DM-/CKD- patients. Among the DM + /CKD + patients, after adjustment, there were no significant differences in the primary endpoints between the experimental and reference regimen; however, the experimental regimen was associated with lower rates of POCE (20.6% versus 25.9%, HR 0.74; 95% CI [0.55–0.99], p = 0.043, p_interaction = 0.155) and NACE (22.7% versus 28.3%, HR 0.75; 95% CI [0.56–0.99], p = 0.044, p_interaction = 0.310), which was mainly driven by a lower rate of all revascularization, as compared with the reference regimen. The landmark analysis showed that while the experimental and reference regimen had similar rates of all the clinical endpoints during the first year, the experimental regimen was associated with significantly lower rates of POCE (5.8% versus 11.0%, HR 0.49; 95% CI [0.29–0.82], p = 0.007, p_interaction = 0.040) and NACE (5.8% versus 11.2%, HR 0.48; 95% CI [0.29–0.82], p = 0.007, p_interaction = 0.013) in the second year.

Conclusion

Among patients with both DM and CKD, ticagrelor monotherapy was not associated with lower rates of all-cause death or new Q-wave, or major bleeding complications; however, it was associated with lower rates of POCE and NACE. These findings should be interpreted as hypothesis-generating.

Clinical Trial Registration: ClinicalTrials.gov (NCT01813435).

Risk of herpes zoster among patients with predialysis chronic kidney disease in a cohort study in Taiwan

BACKGROUND/OBJECTIVE

Patients on chronic dialysis are at risk of developing herpes zoster, but little systematic research focuses on the association between predialysis chronic kidney disease and herpes zoster. The objective of the study was to explore the association between predialysis chronic kidney disease and herpes zoster in Taiwan.

METHODS

A nation-based retrospective cohort study was performed using the 2005-2012 database of the Taiwan National Health Insurance Program. There were 16 655 subjects aged 20-84 years with newly diagnosed predialysis chronic kidney disease as the study group and 33 310 randomly selected subjects without chronic kidney disease as the comparison group. Both groups were matched with sex, age, comorbidities and the year of the index date. The incidence rates of herpes zoster in both groups were calculated. The multivariable Cox proportional hazards regression model was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for herpes zoster associated with predialysis chronic kidney disease.

RESULTS

The overall incidence rate of herpes zoster was 1.4-fold higher in the predialysis chronic kidney disease group than that in the non-chronic kidney disease group (8.76 vs 6.27 per 1000 person-years, 95% CI 1.27-1.54; P < .001). After controlling for co-variables, the adjusted HR of herpes zoster was 1.38 (95% CI 1.25-1.53; P < .001) for subjects with predialysis chronic kidney disease compared with non-chronic kidney disease subjects. The adjusted HR increased to 1.65 for subjects with predialysis chronic kidney disease and with any comorbidity (95% CI 1.42-1.92; P < .001).

CONCLUSIONS

Patients with predialysis chronic kidney disease correlate with approximately 1.4-fold increased hazard of developing herpes zoster.

Heart failure and chronic kidney disease manifestation and mortality risk associations in type 2 diabetes: A large multinational cohort study

AIMS

To examine the manifestation of cardiovascular or renal disease (CVRD) in patients with type 2 diabetes (T2D) initially free from CVRD as well as the mortality risks associated with these diseases.

METHODS

Patients free from CVRD were identified from healthcare records in England, Germany, Japan, the Netherlands, Norway and Sweden at a fixed date. CVRD manifestation was defined by first diagnosis of cardiorenal disease, or a stroke, myocardial infarction (MI) or peripheral artery disease (PAD) event. The mortality risk associated with single CVRD history of heart failure (HF), chronic kidney disease (CKD), MI, stroke or PAD was compared with that associated with CVRD-free status.

RESULTS

Of 1 177 896 patients with T2D, 772 336 (66%) were CVRD-free and followed for a mean of 4.5 years. A total of 137 081 patients (18%) developed a first CVRD manifestation, represented by CKD (36%), HF (24%), stroke (16%), MI (14%) and PAD (10%). HF or CKD was associated with increased cardiovascular and all-cause mortality risk: hazard ratio (HR) 2.02 (95% confidence interval [CI] 1.75-2.33) and HR 2.05 (95% CI 1.82-2.32), respectively. HF and CKD were separately associated with significantly increased mortality risks, and the combination was associated with the highest cardiovascular and all-cause mortality risk: HRs 3.91 (95% CI 3.02-5.07) and 3.14 (95% CI 2.90-3.40), respectively.

CONCLUSION

In a large multinational study of >750 000 CVRD-free patients with T2D, HF and CKD were consistently the most frequent first cardiovascular disease manifestations and were also associated with increased mortality risks. These novel findings show these cardiorenal diseases to be important and serious complications requiring improved preventive strategies.

RENA Study: Cross-Sectional Study to Evaluate CKD Prevalence in Portugal

INTRODUCTION

Chronic kidney disease (CKD) is a major global public health problem associated with increased risk of cardiovascular morbidity, premature mortality, and decreased quality of life. In Portugal, the PREVADIAB study showed a prevalence of CKD stages 3-5 of 6.1%. To overcome the limitations of the PREVADIAB study, the RENA study aimed to provide an estimate of the prevalence of CKD at a national level and to characterize CKD patients.

METHODS

This was a cross-sectional study including users of Primary Health Care Units aged 18 or more. After obtaining written informed consent, sociodemographic and clinical data were recorded through a structured questionnaire, anthropometric measurements were taken, and blood and urine samples were collected. All participants initially meeting the criteria for CKD were contacted at least 3 months after the initial assessment for confirmation of the analytical results.

RESULTS

A total of 3,135 individuals were included, 65.4% were female, and the mean age was 56.7 ± 15.9 years. The prevalence of hypertension, dyslipidemia, and diabetes was 38, 32, and 16%, respectively, and 31% were obese. After data adjustment by gender, age group, and geographical region, the global prevalence of CKD was 20.9% (95% CI: 6.5-35.3%), with no differences between genders and a significant increase with the advance of the age groups.

CONCLUSION

Our study showed a CKD prevalence above the worldwide and Europe average. Despite the study limitations, it has become clear that it is urgent to identify CKD patients earlier and to develop awareness and educational programs to prevent CKD and its associated diseases.

Rhubarb Enema Improved Colon Mucosal Barrier Injury in 5/6 Nephrectomy Rats May Associate With Gut Microbiota Modification

Chronic kidney disease (CKD) is often accompanied with colon mucosal barrier damage and gut microbiota disturbance, which strongly associate with up-regulated inflammation and kidney tubulointerstitial fibrosis. However, few interventions could protect the damaged barrier effectively. Rheum palmatum L or rhubarb is a common herbal medicine which is widely used to protect the colon mucosal barrier. In previous studies, we found that rhubarb intervention may reduce renal inflammation and tubulointerstitial fibrosis, via gut microbiota modification. However, whether intestinal barrier function could be improved by rhubarb intervention and the relationship with intestinal flora are still unknown. Therefore, we investigated the effects of rhubarb enema on intestinal barrier, and further analyzed the relationship with gut microbiota in 5/6 nephrectomy rats. Results indicated that rhubarb enema improved the intestinal barrier, regulated gut microbiota dysbiosis, suppressed systemic inflammation, and alleviated renal fibrosis. More specifically, rhubarb enema treatment inhibited the overgrowth of conditional pathogenic gut bacteria, including Akkermansia, Methanosphaera, and Clostridiaceae in CKD. The modification of gut microbiota with rhubarb intervention displayed significant correlation to intestinal barrier markers, TLR4–MyD88–NF-κB inflammatory response, and systemic inflammation. These results revealed that rhubarb enema could restore intestinal barrier by modifying several functional enteric bacteria, which may further explain the renal protection mechanism of the rhubarb enema.

Impact of Diabetes Mellitus and Chronic Kidney Disease on Cardiovascular Outcomes and Platelet P2Y12 Receptor Antagonist Effects in Patients With Acute Coronary Syndromes: Insights From the PLATO Trial

Background

There are limited data on how the combination of diabetes mellitus (DM) and chronic kidney disease (CKD) affects cardiovascular outcomes as well as response to different P2Y₁₂ receptor antagonists, which represented the aim of the present investigation.

Methods and Results

In this post hoc analysis of the PLATO (Platelet Inhibition and Patient Outcomes) trial, which randomized acute coronary syndrome patients to ticagrelor versus clopidogrel, patients (n=15 108) with available DM and CKD status were classified into 4 groups: DM+/CKD+ (n=1058), DM+/CKD− (n=2748), DM−/CKD+ (n=2160), and DM−/CKD− (n=9142). The primary efficacy end point was a composite of cardiovascular death, myocardial infarction, or stroke at 12 months. The primary safety end point was PLATO major bleeding. DM+/CKD+ patients had a higher incidence of the primary end point compared with DM−/CKD− patients (23.3% versus 7.1%; adjusted hazard ratio 2.22; 95% CI 1.88–2.63; P<0.001). Patients with DM+/CKD− and DM−/CKD+ had an intermediate risk profile. The same trend was shown for the individual components of the primary end point and for major bleeding. Compared with clopidogrel, ticagrelor reduced the incidence of the primary end point consistently across subgroups (P‐interaction=0.264), but with an increased absolute risk reduction in DM+/CKD+. The effects on major bleeding were also consistent across subgroups (P‐interaction=0.288).

Conclusions

In acute coronary syndrome patients, a gradient of risk was observed according to the presence or absence of DM and CKD, with patients having both risk factors at the highest risk. Although the ischemic benefit of ticagrelor over clopidogrel was consistent in all subgroups, the absolute risk reduction was greatest in patients with both DM and CKD.

Clinical Trial Registration

URL: http://www.clinicatrials.gov. Unique identifier: NCT00391872.

A Pilot Study of a Natural Food Supplement as New Possible Therapeutic Approach in Chronic Kidney Disease Patients

The identification of natural bioactive compounds, able to counteract the abnormal increase of oxidative stress and inflammatory status in chronic degenerative non-communicable diseases is useful for the clinical management of these conditions. We tested an oral food supplement (OFS), chemically characterized and evaluated for in vitro and in vivo activity. Vitamin C, analyzed by High Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD), was 0.19 mg/g in rosehip dry extract and 15.74 mg/capsule in the OFS. The identification of polyphenols was performed by HPLC-DAD; the total antioxidant capacity was assessed by Folin-Ciocalteu test. Total polyphenols were 14.73 mg/g gallic acid equivalents (GAE) for rosehip extract and 1.93 mg/g GAE for OFS. A total of 21 chronic kidney disease (CKD) patients and 10 healthy volunteers were recruited. The evaluation of routine laboratory and inflammatory parameters, erythrocyte glutathione transferase (e-GST), human oxidized serum albumin (HSAox), and assessment of body composition were performed at two different times, at baseline and after 5 weeks of OFS assumption. In the study, we highlighted a significant decrease of traditional inflammatory biomarkers (such as C-reactive protein, erythrocyte sedimentation rate, platelet to lymphocyte ratio) and other laboratory parameters like e-GST, azotaemia, and albuminuria after OFS treatment in CKD patients. Moreover, we demonstrated a lipid profile improvement in CKD patients after OFS supplementation.

Bypass Grafting vs Endovascular Therapy in Patients With Non-Dialysis-Dependent Chronic Kidney Disease and Chronic Limb-Threatening Ischemia (CRITISCH Registry)

Purpose: To report the outcomes of bypass grafting (BG) vs endovascular therapy (EVT) in patients with non-dialysis-dependent chronic kidney disease (CKD) and chronic limb-threatening ischemia (CLTI). Materials and Methods: The CRITISCH Registry is a prospective, national, interdisciplinary, multicenter registry evaluating the current practice of all available treatment options in 1200 consecutive CLTI patients. For the purposes of this analysis, only the 337 patients with non-dialysis-dependent CKD treated by either BG (n=86; median 78 years, 48 men) or EVT (n=251; median age 80 years, 135 men) were analyzed. The primary composite outcome was amputation-free survival (AFS); secondary outcomes were overall survival (OS) and amputation-free time (AFT). All outcomes were evaluated in Cox proportional hazards models; the results are reported as the hazard ratio (HR) and 95% confidence interval (CI). Results: The Cox regression analysis revealed a significantly greater hazard of amputation or death after BG (HR 1.78, 95% CI 1.05 to 3.03, p=0.028). The models for AFT and overall survival also suggested a higher hazard for BG, but the differences were not significant (AFT: HR 1.66, 95% CI 0.78 to 3.53, p=0.188; OS: HR 1.41, 95% CI 0.80 to 2.47, p=0.348). The absence of runoff vessels (HR 1.73, 95% CI 1.15 to 2.60, p=0.008) was associated with a decreased AFS. The likelihood of amputation was higher in male patients (HR 2.21, 95% CI 1.10 to 4.45, p=0.027) and was associated with a lack of runoff vessels (HR 1.95, 95% CI 0.96 to 3.95, p=0.065) and myocardial infarction (HR 3.74, 95% CI 1.23 to 11.35, p=0.020). Death was more likely in patients without runoff vessels (HR 1.76, 95% CI 1.11 to 2.80, p=0.016) and those with a higher risk score (HR 1.73, 95% CI 1.03 to 2.91, p=0.038). Conclusion: This analysis suggested that BG was associated with poorer AFS than EVT in patients with non-dialysis-dependent CKD and CLTI. Male sex, previous myocardial infarction, and the absence of runoff vessels were additionally identified as predictors of poorer outcomes.

The prevalence of chronic kidney disease in Iceland according to KDIGO criteria and age-adapted estimated glomerular filtration rate thresholds

Most epidemiological studies on chronic kidney disease (CKD) are based solely on estimated glomerular filtration rate (eGFR). Few studies have included proteinuria, while the chronicity criterion is usually omitted. To explore this, we examined the prevalence of CKD stages 1-5 in Iceland based on multiple markers of kidney damage. All serum creatinine values, urine protein measurements and diagnostic codes for kidney diseases and comorbid conditions for people aged 18 years and older were obtained from electronic medical records of all healthcare institutions in Iceland in 2008-2016. CKD was defined according to the Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline using diagnoses indicative of a chronic kidney disease, proteinuria and/or an eGFR under 60 mL/min/1.73 m² for over three months. Mean annual age-standardized prevalence of CKD stages 1-5 was calculated based on the KDIGO criteria and age-adapted eGFR thresholds from 2,120,147 creatinine values for 218,437 individuals, 306,531 proteinuria measurements for 86,364 individuals and 6973 individuals carrying a kidney disease diagnosis. Median age was 63 years (range, 18-106) and 47% were male. The mean annual age standardized CKD prevalence was 5.13% for men and 6.75% for women using the KDIGO criteria but by age-adapted eGFR cut-offs, the prevalence was 3.27% for men and 4.01% for women. Thus, our nationwide study, defining CKD in Iceland with strict adherence to the KDIGO criteria, demonstrates a lower prevalence of CKD than anticipated from most previous studies.

Evidence-based medicine-When observational studies are better than randomized controlled trials

In evidence-based medicine, clinical research questions may be addressed by different study designs. This article describes when randomized controlled trials (RCT) are needed and when observational studies are more suitable. According to the Centre for Evidence-Based Medicine, study designs can be divided into analytic and non-analytic (descriptive) study designs. Analytic studies aim to quantify the association of an intervention (eg, treatment) or a naturally occurring exposure with an outcome. They can be subdivided into experimental (ie, RCT) and observational studies. The RCT is the best study design to evaluate the intended effect of an intervention, because the randomization procedure breaks the link between the allocation of the intervention and patient prognosis. If the randomization of the intervention or exposure is not possible, one needs to depend on observational analytic studies, but these studies usually suffer from bias and confounding. If the study focuses on unintended effects of interventions (ie, effects of an intervention that are not intended or foreseen), observational analytic studies are the most suitable study designs, provided that there is no link between the allocation of the intervention and the unintended effect. Furthermore, non-analytic studies (ie, descriptive studies) also rely on observational study designs. In summary, RCTs and observational study designs are inherently different, and depending on the study aim, they each have their own strengths and weaknesses.

Cost-Effectiveness Analysis of Patiromer in Combination with Renin-Angiotensin-Aldosterone System Inhibitors for Chronic Kidney Disease in Sweden

OBJECTIVES

Patients with chronic kidney disease (CKD) are commonly treated with renin-angiotensin-aldosterone system inhibitors (RAASi) in order to delay progression of renal disease. However, research has shown that RAASi in CKD patients increases hyperkalaemia (HK) prevalence, which leads to RAASi discontinuation or dose reduction with the loss of benefits on the kidney. Patiromer is a novel therapy for HK treatment and may enable patients to remain on their RAASi regimen. This study aimed to assess the cost-effectiveness of patiromer from a Swedish healthcare perspective.

METHODS

A Markov model was developed to evaluate the economic outcomes of patiromer versus no patiromer in HK patients with stage 3-4 CKD taking RAASi. The model consisted of six health states reflecting disease progression and hospitalisations. The analysis mainly considered clinical data from the OPAL-HK trial and national costs. The main outcomes of interest were incremental costs (euro [EUR] 2016) and quality-adjusted life years (QALYs), discounted at 3%, and the incremental cost-effectiveness ratio (ICER). Extensive uncertainty analyses were performed.

RESULTS

In comparison to no patiromer, a patiromer patient gained 0.14 QALYs and an incremental cost of EUR 6109 (Swedish krona [SEK] 57,850), yielding an ICER of EUR 43,307 (SEK 410,072)/QALY gained. The results were robust to a range of sensitivity analyses. At a willingness-to-pay threshold of EUR 52,804 (SEK 500,000)/QALY, patiromer had a 50% chance of being cost-effective.

CONCLUSIONS

The results indicate that patiromer may demonstrate value for money in Swedish patients with stage 3-4 CKD, by enabling RAASi treatment. However, there is a considerable degree of uncertainty.

From obesity through gut microbiota to cardiovascular diseases: a dangerous journey

The co-existence of humans and gut microbiota started millions of years ago. Until now, a balance gradually developed between gut bacteria and their hosts. It is now recognized that gut microbiota are key to form adequate immune and metabolic functions and, more in general, for the maintenance of good health. Gut microbiota are established before birth under the influence of maternal nutrition and metabolic status, which can impact the future metabolic risk of the offspring in terms of obesity, diabetes, and cardiometabolic disorders during the lifespan. Obesity and diabetes are prone to disrupt the gut microbiota and alter the gut barrier permeability, leading to metabolic endotoxaemia with its detrimental consequences on health. Specific bacterial sequences are now viewed as peculiar signatures of the metabolic syndrome across life stages in each individual, and are linked to pathogenesis of cardiovascular diseases (CVDs) via metabolic products (metabolites) and immune modulation. These mechanisms have been linked, in association with abnormalities in microbial richness and diversity, to an increased risk of developing arterial hypertension, systemic inflammation, nonalcoholic fatty liver disease, coronary artery disease, chronic kidney disease, and heart failure. Emerging strategies for the manipulation of intestinal microbiota represent a promising therapeutic option for the prevention and treatment of CVD especially in individuals prone to CV events.

Wnt signaling pathway in aging-related tissue fibrosis and therapies

Fibrosis is the final hallmark of pathological remodeling, which is a major contributor to the pathogenesis of various chronic diseases and aging-related organ failure to fully control chronic wound-healing and restoring tissue function. The process of fibrosis is involved in the pathogenesis of the kidney, lung, liver, heart and other tissue disorders. Wnt is a highly conserved signaling in the aberrant wound repair and fibrogenesis, and sustained Wnt activation is correlated with the pathogenesis of fibrosis. In particular, mounting evidence has revealed that Wnt signaling played important roles in cell fate determination, proliferation and cell polarity establishment. The expression and distribution of Wnt signaling in different tissues vary with age, and these changes have key effects on maintaining tissue homeostasis. In this review, we first describe the major constituents of the Wnt signaling and their regulation functions. Subsequently, we summarize the dysregulation of Wnt signaling in aging-related fibrotic tissues such as kidney, liver, lung and cardiac fibrosis, followed by a detailed discussion of its involvement in organ fibrosis. In addition, the crosstalk between Wnt signaling and other pathways has the potential to profoundly add to the complexity of organ fibrosis. Increasing studies have demonstrated that a number of Wnt inhibitors had the potential role against tissue fibrosis, specifically in kidney fibrosis and the implications of Wnt signaling in aging-related diseases. Therefore, targeting Wnt signaling might be a novel and promising therapeutic strategy against aging-related tissue fibrosis.

A systematic review and meta-analysis of the risk of death and patency after application of paclitaxel-coated balloons in the hemodialysis access

OBJECTIVE

The comparison between paclitaxel-coated balloon (PCB) angioplasty and plain balloon angioplasty (PBA) for hemodialysis (HD) access stenosis or occlusion has not been well investigated. The objectives of this systematic review and meta-analysis were to compare all-cause mortality, HD access primary patency, and circuit primary patency after endovascular maintenance procedures using PCB angioplasty vs PBA.

METHODS

MEDLINE, Embase, and Cochrane Databases were systematically searched to identify all the relevant studies on paclitaxel-coated devices for stenosis or thrombosis of HD access. A random effects model was applied to pool the effect measures. Dichotomous data were presented using an odds ratio (OR). Effect data were presented using pooled hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

A total of 16 studies were included in this meta-analysis, 12 randomized controlled trials and 4 cohort studies involving 1086 patients who underwent endovascular treatment for HD access stenosis or occlusion. All-cause mortality rates at 6, 12, and 24 months after intervention were similar between the PCB and PBA groups (6 months: OR, 1.06 [95% CI, 0.38-2.96; P = .907; I² = 19.2%]; 12 months: OR, 1.20 [95% CI, 0.66-2.16; P = .554; I² = 0%]; 24 months: OR, 1.43 [95% CI, 0.83-2.45; P = .195; I² = 0%]). There was a significant improvement of primary patency in the PCB group compared with the PBA group (HR, 0.47; 95% CI, 0.33-0.69; P < .001; I² = 67.3%). This benefit was consistent with the analysis of randomized controlled trials, whereas cohort studies were excluded. Further subgroup analysis of target lesions demonstrated that primary patency was significantly higher in the PCB group than in the PBA group, not only for arteriovenous fistula (HR, 0.54; 95% CI, 0.30-0.98; P = .041; I² = 76.8%) but also for central venous stenosis (HR, 0.39; 95% CI, 0.22-0.71; P = .002; I² = 0%). The PCB group was associated with higher 6-month (OR, 0.40; 95% CI, 0.27-0.59; P < .001) and 24-month lesion primary patency (OR, 0.28; 95% CI, 0.11-0.72; P = .009) than PBA and was marginally associated with 12-month lesion primary patency (OR, 0.52; 95% CI, 0.26-1.03; P = .06). Circuit primary patency analysis showed a marginal trend toward better outcome in the PCB group (HR, 0.63; 95% CI, 0.40-1.00) but no statistical significance (P = .052).

CONCLUSIONS

This systematic review and meta-analysis demonstrated that PCB angioplasty is associated with significantly improved primary patency of arteriovenous fistula and central venous stenosis for HD access maintenance, with no evidence of increasing all-cause mortality based on short-term and midterm follow-up. Further large cohort study is needed to investigate long-term mortality.

Prevalence and Risk Factors of CKD in South Kivu, Democratic Republic of Congo: A Large-Scale Population Study

Background

The prevalence of chronic kidney disease (CKD) in African American individuals is high but whether this applies to native populations in sub-Saharan Africa is unclear.

Methods

In a cross-sectional study, we assessed the prevalence and risk factors of CKD in rural and urban adults in South Kivu, Democratic Republic of Congo. Glomerular filtration rate (GFR) was estimated using the CKD–Epidemiology Collaboration (CKD-EPI) equations based on serum creatinine (eGFRcr), cystatin C (eGFRcys), or both markers (eGFRcr-cys), without ethnic correction factor. CKD was defined as an eGFR <60 ml/min per 1.73 m² and/or albuminuria (albumin-to-creatinine ratio ≥30 mg/g).

Results

A total of 1317 participants aged 41.1 ± 17.1 years (730 rural, 587 urban) were enrolled. The prevalence of hypertension (20.2%; 95% confidence interval [CI], 18–22.3), diabetes mellitus (4.3%; 95% CI, 3.2–5.4) and obesity (8.9%; 95% CI, 7.4–10.5) was higher in urban than rural participants (all P < 0.05). HIV infection prevalence was 0.41% (95% CI, 0.05–0.78). The prevalence of eGFRcr <60 ml/min per 1.73 m² was 5.4% (95% CI, 4.2–6.7). The prevalence of albuminuria was 6.6% (95 % CI, 5.1–8.1). The overall prevalence of CKD was 12.2% (95% CI, 10.2–14.2) according to CKD-EPIcr. Factors independently associated with CKD-EPIcr were older age (adjusted odds ratio [aOR], 1.05 [1.04–1.07]), urban residence (aOR 1.86 [1.18–2.95]), female sex (aOR 1.66 [1.04–2.66]), hypertension (aOR 1.90 [1.15–3.12]), diabetes (aOR 2.03 [1.02–4.06]), and HIV infection (10.21 [2.75–37.85]). The results based on eGFRcys or eGFRcr-cys were largely consistent with the preceding.

Conclusion

Overall, the burden of CKD is substantial (>11%), predominantly in the urban area, and largely driven by classic risk factors (gender, aging, HIV, hypertension, and diabetes).

GFR in Healthy Aging: an Individual Participant Data Meta-Analysis of Iohexol Clearance in European Population-Based Cohorts

BACKGROUND

Population mean GFR is lower in older age, but it is unknown whether healthy aging is associated with preserved rather than lower GFR in some individuals.

METHODS

We investigated the cross-sectional association between measured GFR, age, and health in persons aged 50-97 years in the general population through a meta-analysis of iohexol clearance measurements in three large European population-based cohorts. We defined a healthy person as having no major chronic disease or risk factors for CKD and all others as unhealthy. We used a generalized additive model to study GFR distribution by age according to health status.

RESULTS

There were 935 (22%) GFR measurements in persons who were healthy and 3274 (78%) in persons who were unhealthy. The mean GFR was lower in older age by -0.72 ml/min per 1.73 m² per year (95% confidence interval [95% CI], -0.96 to -0.48) for men who were healthy versus -1.03 ml/min per 1.73 m² per year (95% CI, -1.25 to -0.80) for men who were unhealthy, and by -0.92 ml/min per 1.73 m² per year (95% CI, -1.14 to -0.70) for women who were healthy versus -1.22 ml/min per 1.73 m² per year (95% CI, -1.43 to -1.02) for women who were unhealthy. For healthy and unhealthy people of both sexes, both the 97.5th and 2.5th GFR percentiles exhibited a negative linear association with age.

CONCLUSIONS

Healthy aging is associated with a higher mean GFR compared with unhealthy aging. However, both the mean and 97.5 percentiles of the GFR distribution are lower in older persons who are healthy than in middle-aged persons who are healthy. This suggests that healthy aging is not associated with preserved GFR in old age.

Longitudinal trends in the prevalence of hyperuricaemia and chronic kidney disease in hypertensive and normotensive adults

The purpose: To evaluate longitudinal trends in the prevalence of hyperuricaemia and chronic kidney disease (CKD) in Czech adults with and without arterial hypertension (HT).Materials and methods: Two independent cross-sectional surveys were performed in 2006-2009 and 2015-2018, each screening involving 1% population random sample of the general population of nine districts of the Czech Republic aged 25-64 years, stratified by age and gender. Hyperuricaemia was defined as serum uric acid ≥ 420 μmol/l in men, and ≥ 360 μmol/l in women. CKD was defined as estimated glomerular filtration rate < 60 ml/min/1.73 m² and/or albumin/creatinine ratio ≥ 3 mg/mmol.Results: Final analyses included 3504 individuals examined in 2006-2009, and 2309 in 2015-2018. The overall prevalence of hyperuricaemia increased from 16.4% to 25.2% in men (p < 0.001), and from 7.6% to 10.9% in women (p < 0.001), whereas the overall prevalence of CKD declined from 6.8% to 3.6% in men (p = 0.001), and from 7.6% to 4.8% in women (p < 0.001). There was no interaction between HT and hyperuricaemia in either gender; the increase in hyperuricaemia prevalence was observed both in hypertensive and normotensive adults and was accompanied by the increased prevalence of abdominal obesity. Contrarily, there was an interaction between HT and CKD in both men (p < 0.001) and women (p = 0.011); the CKD prevalence declined only in hypertensive individuals, specifically in those using antihypertensive medication and was accompanied by the increased use of renin-angiotensin-aldosterone system (RAS) inhibitors and calcium channel blockers (CCBs).Conclusions: Over the period of 10 years, the overall prevalence of hyperuricaemia increased, while the prevalence of CKD decreased. An increase in the prevalence of hyperuricaemia was observed both in hypertensive and normotensive individuals and was accompanied by an increase in the prevalence of abdominal obesity. A decline in the prevalence of CKD was only observed in hypertensive individuals and was accompanied by the increased use of RAS inhibitors and CCBs.

Longitudinal Changes in Kidney Function Estimated from Cystatin C and Its Association with Mortality in Elderly Women

BACKGROUND/AIMS

Prospective data on age-related changes in kidney function are required, especially since the current Kidney Disease Improving Global Outcomes (KDIGO) definition has been suggested to classify a large number of elderly people with CKD.

OBJECTIVE

This study, a complement to our previous Cr-based study in the same cohort, is aimed at evaluating cystatin C (cysC)-based changes in kidney function during aging in older women and analyzing the association between CKD and mortality through 10 years of follow-up.

METHODS

cysC was available in 981 women from the Osteoporosis Prospective Risk Assessment (OPRA) cohort, all aged 75 years on entry. Reinvestigations were made after 5 (n = 685) and 10 years (n = 365). Kidney function was estimated (estimated glomerular filtration rate [eGFR]) using Chronic Kidney Disease Epidemiology Collaboration cysC and Caucasian, Asian, Pediatric, and Adult cysC equations and the change in function calculated. Women were staged equivalent to CKD stage 1, 2, 3a, or 3b-5 according to the KDIGO classification. Mortality risk was estimated for 5-year or 10-year follow-up time using Cox proportional hazard analyses (reference category, CKD stages 1 and 2).

RESULTS

Mortality risk for women with the worst kidney function (CKD stages 3b-5) increased during both 5-year follow-up times compared to that for women in stages 1 and 2 (age 75-80 years: adjusted Hazard Ratio [HRadj] 3.9, 95% confidence interval [CI] 2.3-6.5; age 80-85 years: HRadj 1.7, 95% CI 1.0-2.7). In contrast, women in stage 3a had increased risk only in the first 5-year follow-up (HRadj 1.7, 95% CI 1.0-3.0, age 75-80 years). Change in kidney function amounted to a loss of 1.9 (±1.4) mL/min/1.73 m2 per year during the 10-year follow-up, and at age 85 years, 4 of every 5 women had an eGFR equivalent to CKD.

CONCLUSION

In the future, an age-adapted definition of CKD, lowering the threshold for CKD in the elderly, may be beneficial to avoid overdiagnosis of CKD.

Association between lifestyle factors and decreased kidney function in older adults: a community-based cross-sectional analysis of the Taipei City elderly health examination database

BACKGROUND

Impaired kidney function is the hallmark of chronic kidney disease (CKD), and is associated with increased risk of all-cause mortality in the elderly. In the present cross-sectional population-based study, we aimed to evaluate the associations between lifestyle factors (exercise habit, alcohol consumption, smoking history, and betel nut chewing) and decreased kidney function.

METHODS

The data from the Taipei City Elderly Health Examination Database (2006 to 2012) were extracted. Associations between risk factors and reduced estimated Glomerular filtration rate (eGFR) were evaluated by regression and stratification analyses.

RESULTS

A total of 297,603 participants were included in the final analysis, and 29.7% of them had reduced eGFR. Smoking was significantly associated with an elevated risk of reduced eGFR. While, physical exercise conferred to a significantly decreased adjusted odds ratio (aOR) in reduced eGFR (regular exercise, aOR = 0.79; occasional exercise, aOR = 0.87). Furthermore, the protective effect of exercise habit against reduced eGFR was not affected by comorbid conditions, such as hypertension, diabetes, obesity, and cardiovascular disease.

CONCLUSIONS

Engaging in physical exercise was beneficially associated with reduced eGFR in older individuals. Longitudinal or prospective studies are warranted for confirmation and extrapolation of the current findings.

Trimethylamine N-Oxide in Relation to Cardiometabolic Health-Cause or Effect?

Trimethylamine-N-oxide (TMAO) is generated in a microbial-mammalian co-metabolic pathway mainly from the digestion of meat-containing food and dietary quaternary amines such as phosphatidylcholine, choline, betaine, or L-carnitine. Fish intake provides a direct significant source of TMAO. Human observational studies previously reported a positive relationship between plasma TMAO concentrations and cardiometabolic diseases. Discrepancies and inconsistencies of recent investigations and previous studies questioned the role of TMAO in these diseases. Several animal studies reported neutral or even beneficial effects of TMAO or its precursors in cardiovascular disease model systems, supporting the clinically proven beneficial effects of its precursor, L-carnitine, or a sea-food rich diet (naturally containing TMAO) on cardiometabolic health. In this review, we summarize recent preclinical and epidemiological evidence on the effects of TMAO, in order to shed some light on the role of TMAO in cardiometabolic diseases, particularly as related to the microbiome.

Developing quality indicators for Chronic Kidney Disease in primary care, extractable from the Electronic Medical Record. A Rand-modified Delphi method

BACKGROUND

Chronic kidney disease (CKD) is a common chronic condition and a rising public health issue with increased morbidity and mortality, even at an early stage. Primary care has a pivotal role in the early detection and in the integrated management of CKD which should be of high quality. The quality of care for CKD can be assessed using quality indicators (QIs) and if these QIs are extractable from the electronic medical record (EMR) of the general physician, the number of patients whose quality of care can be evaluated, could increase vastly. Therefore the aim of this study is to develop QIs which are evidence based, EMR extractable and which can be used as a framework to automate quality assessment.

METHODS

We used a Rand-modified Delphi method to develop QIs for CKD in primary care. A questionnaire was designed by extracting recommendations from international guidelines based on the SMART principle and the EMR extractability. A multidisciplinary expert panel, including patients, individually scored the recommendations for measuring high quality care on a 9-point Likert scale. The results were analyzed based on the median Likert score, prioritization and agreement. Subsequently, the recommendations were discussed in a consensus meeting for their in- or exclusion. After a final appraisal by the panel members this resulted in a core set of recommendations, which were then transformed into QIs.

RESULTS

A questionnaire composed of 99 recommendations was extracted from 10 international guidelines. The consensus meeting resulted in a core set of 36 recommendations that were translated into 36 QIs. This final set consists of QIs concerning definition & classification, screening, diagnosis, management consisting of follow up, treatment & vaccination, medication & patient safety and referral to a specialist. It were mostly the patients participating in the panel who stressed the importance of the QIs concerning medication & patient safety and a timely referral to a specialist.

CONCLUSION

This study provides a set of 36 EMR extractable QIs for measuring the quality of primary care for CKD. These QIs can be used as a framework to automate quality assessment for CKD in primary care.

Chronic Kidney Disease Management in General Practice: A Focus on Inappropriate Drugs Prescriptions

Nephrotoxic drugs prescriptions are often prescribed inappropriately by general practitioners (GPs), increasing the risk of chronic kidney disease (CKD). The aim of this study was to detect inappropriate prescriptions in patients with CKD and to identify their predictive factors. A retrospective study on patients with creatinine values recorded in the period 2014-2016 followed by 10 GPs was performed. The estimated glomerular filtration rate (eGFR) was used to identify CKD patients. The demographic and clinical characteristics and drugs prescriptions were collected. A descriptive analysis was conducted to compare the characteristics and logistic regression models to estimate the predictive factors of inappropriate prescriptions. Of 4098 patients with creatinine values recorded, 21.9% had an eGFR <60 mL/min/1.73m². Further, 56.8% received inappropriate prescriptions, with a significantly lower probability in subjects with at least a nephrologist visit (Adj OR 0.54 (95% CI 0.36-0.81)) and a greater probability in patients treated with more active substances (1.10 (1.08-1.12)), affected by more comorbidities (1.14 (1.06-1.230)), or with serious CKD (G4/G5 21.28 (7.36-61.57)). Nonsteroidal anti-inflammatory drugs (NSAIDs) were the most used contraindicated drugs (48.5%), while acetylsalicylic acid was the most inappropriately prescribed (39.5%). Our results highlight the inappropriate prescriptions for CKD authorized by GPs and underline the need of strategies to improve prescribing patterns.

Chronic kidney disease progression and mortality risk profiles in Germany: results from the Chronic Kidney Disease Outcomes and Practice Patterns Study

BACKGROUND

Chronic kidney disease (CKD) progression among German patients in a representative setting has not been described previously. The Verband Deutsche Nierenzentren and Chronic Kidney Disease Outcomes and Practice Patterns Study established a longitudinal observational cohort among German CKD patients to research variations in patient care and outcomes in real-world nephrology practices.

METHODS

A cohort of CKD Stages 3 (25%) and 4 (75%) patients was established from German nephrologist-run CKD clinics in 2013-16. Linear models were used to determine the estimated glomerular filtration rate (eGFR) slope during follow-up and Cox models were used to assess outcomes of end-stage kidney disease (ESKD) and death.

RESULTS

A total of 1834 patients (median age 75 years, 58% male, 42% diabetics, median baseline eGFR 25 mL/min/1.73 m2) were followed for a median of 29 months. More than 50% had slow or no decline and 17% declined ≥5 mL/min/1.73 m2/year. After 4.5 years, the incidence of ESKD was 8% and of deaths without ESKD 16% among patients with eGFR ≥30 mL/min/1.73 m2 and 37% and 19% for eGFR <30 mL/min/1.73 m2. Adjusted models showed higher risks of ESKD or death for patients with worse kidney function at baseline, male sex, diabetes and higher blood pressure; a higher risk of ESKD with higher albuminuria; and a higher risk of death with older age or cardiovascular comorbidity.

CONCLUSIONS

Routine nephrology care of patients in Germany comprises mostly elderly patients, many with slow CKD progression. Identification of risk factors for CKD progression and mortality may help guide resources by closer follow-up of high-risk patients.

Association of Serum Uromodulin with Death, Cardiovascular Events, and Kidney Failure in CKD

BACKGROUND AND OBJECTIVES

Uromodulin is exclusively produced by tubular epithelial cells and released into urine and serum. Higher serum uromodulin has been associated with lower risk for kidney failure in Chinese patients with CKD and with lower risk for mortality in the elderly and in patients undergoing coronary angiography. We hypothesized that lower serum uromodulin is associated with mortality, cardiovascular events, and kidney failure in white patients with CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured serum uromodulin in 5143 participants enrolled in the German CKD (GCKD) study. The associations of baseline serum uromodulin with all-cause mortality, major adverse cardiovascular events (MACE; a composite of cardiovascular mortality, nonfatal myocardial infarction or stroke, or incident peripheral vascular disease), and kidney failure (dialysis or transplantation) were evaluated using multivariable Cox proportional hazard regression analyses in a cohort study design, adjusting for demographics, eGFR, albuminuria, cardiovascular risk factors, and medication.

RESULTS

The mean age of participants was 60±12 years, 60% were male. Mean serum uromodulin concentration was 98±60 ng/ml, eGFR was 49±18 ml/min per 1.73 m², and 78% had eGFR <60 ml/min per 1.73 m². Participants in lower serum uromodulin quartiles had lower eGFR and higher albuminuria, prevalence of diabetes, hypertension, coronary artery disease, and more frequent history of stroke at baseline. During a follow-up of 4 years, 335 participants died, 417 developed MACE, and 229 developed kidney failure. In multivariable analysis, the highest serum uromodulin quartile was associated with lower hazard for mortality (hazard ratio [HR], 0.57; 95% CI, 0.38 to 0.87), MACE (HR, 0.63; 95% CI, 0.45 to 0.90), and kidney failure (HR, 0.24; 95% CI, 0.10 to 0.55) compared with the lowest quartile.

CONCLUSIONS

Higher serum uromodulin is independently associated with lower risk for mortality, cardiovascular events, and kidney failure in white patients with CKD.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Deutsches Register für Klinische Studien (DRKS; German national database of clinical studies), DRKS00003971.

Clinical Potential of Targeting Fibroblast Growth Factor-23 and αKlotho in the Treatment of Uremic Cardiomyopathy

Chronic kidney disease is highly prevalent, affecting 10% to 15% of the adult population worldwide and is associated with increased cardiovascular morbidity and mortality. As chronic kidney disease worsens, a unique cardiovascular phenotype develops characterized by heart muscle disease, increased arterial stiffness, atherosclerosis, and hypertension. Cardiovascular risk is multifaceted, but most cardiovascular deaths in patients with advanced chronic kidney disease are caused by heart failure and sudden cardiac death. While the exact drivers of these deaths are unknown, they are believed to be caused by uremic cardiomyopathy: a specific pattern of myocardial hypertrophy, fibrosis, with both diastolic and systolic dysfunction. Although the pathogenesis of uremic cardiomyopathy is likely to be multifactorial, accumulating evidence suggests increased production of fibroblast growth factor-23 and αKlotho deficiency as potential major drivers of cardiac remodeling in patients with uremic cardiomyopathy. In this article we review the increasing understanding of the physiology and clinical aspects of uremic cardiomyopathy and the rapidly increasing knowledge of the biology of both fibroblast growth factor-23 and αKlotho. Finally, we discuss how dissection of these pathological processes is aiding the development of therapeutic options, including small molecules and antibodies, directly aimed at improving the cardiovascular outcomes of patients with chronic kidney disease and end-stage renal disease.

NAFLD as a driver of chronic kidney disease

Non-alcoholic fatty liver disease (NAFLD) and chronic kidney disease (CKD) are worldwide public health problems, affecting up to 25-30% (NAFLD), and up to 10-15% (CKD) of the general population. Recently, it has also been established that there is a strong association between NAFLD and CKD, regardless of the presence of potential confounding diseases such as obesity, hypertension and type 2 diabetes. Since NAFLD and CKD are both common diseases that often occur alongside other metabolic conditions, such as type 2 diabetes or metabolic syndrome, elucidating the relative impact of NAFLD on the risk of incident CKD presents a substantial challenge for investigators working in this research field. A growing body of epidemiological evidence suggests that NAFLD is an independent risk factor for CKD and recent evidence also suggests that associated factors such as metabolic syndrome, dysbiosis, unhealthy diets, platelet activation and processes associated with ageing could also contribute mechanisms linking NAFLD and CKD. This narrative review provides an overview of the literature on: a) the evidence for an association and causal link between NAFLD and CKD and b) the underlying mechanisms by which NAFLD (and factors strongly linked with NAFLD) may increase the risk of developing CKD.

The renal range of the κ/λ sFLC ratio: best strategy to evaluate multiple myeloma in patients with chronic kidney disease

Background

Monoclonal serum free light chains (sFLC) are a well-known cause of renal impairment (RI) in patients with multiple myeloma (MM). As an indicator of monoclonality, sFLC ratio has acquired a key role in the diagnosis and monitorization of the disease. However, its interpretation is altered in patients with chronic kidney disease (CKD). This study aims to evaluate the modification of the sFLC ratio reference range in patients with CKD, and propose an optimal range for patients with CKD.

Methods

Serum FLC κ/λ ratio and estimated glomerular filtration rate (eGFR) were retrospectively analyzed in 113 control patients (without hematologic disease), 63 patients with MM in complete remission and 347 patients with active MM. The three groups included patients with CKD (eGFR < 90).

Results

In the group of patients without active MM (n = 176), the sFLC ratio increased at different stages of CKD without pathological significance, with an increase in the number of false positives specially when eGFR is ≤55 ml/min. An optimal range was established for patients with eGFR ≤55 ml/min/1.73 m2: 0.82–3,6 with maximum sensitivity + specificity for that group with an improvement in the Area under the curve (AUC), 0.91 (0.84–0.97) compared with the current ranges proposed by Katzmann and Hutchinson.

Conclusions

This study confirms the influence of eGFR on the interpretation of the sFLC ratio, showing a decreasing specificity in progressive CKD stages when using the reference sFLC range (Katzmann), especially in patients with eFGR ≤55. According to our results, we suggest a modified optimal range (0.82–3,6) for eGFR ≤55 ml/min/1.73 m2. It is necessary to validate this modified range in larger and prospective studies.

Prevalence of chronic kidney disease in the community using data from OxRen: a UK population-based cohort study

Background

Chronic kidney disease (CKD) is a largely asymptomatic condition of diminished renal function, which may not be detected until advanced stages without screening.

Aim

To establish undiagnosed and overall CKD prevalence using a cross-sectional analysis.

Design and setting

Longitudinal cohort study in UK primary care.

Method

Participants aged ≥60 years were invited to attend CKD screening visits to determine whether they had reduced renal function (estimated glomerular filtration rate [eGFR] <60 ml/min/1.73 m² or albumin:creatinine ratio ≥3 mg/mmol). Those with existing CKD, low eGFR, evidence of albuminuria, or two positive screening tests attended a baseline assessment (CKD cohort).

Results

A total of 3207 participants were recruited and 861 attended the baseline assessment. The CKD cohort consisted of 327 people with existing CKD, 257 people with CKD diagnosed through screening (CKD prevalence of 18.2%, 95% confidence interval [CI] = 16.9 to 19.6), and 277 with borderline/transient decreased renal function. In the CKD cohort, 54.4% were female, mean standard deviation (SD) age was 74.0 (SD 6.9) years, and mean eGFR was 58.0 (SD 18.4) ml/min/1.73 m². Of the 584 with confirmed CKD, 44.0% were diagnosed through screening. Over half of the CKD cohort (51.9%, 447/861) fell into CKD stages 3–5 at their baseline assessment, giving an overall prevalence of CKD stages 3–5 of 13.9% (95% CI = 12.8 to 15.1). More people had reduced eGFR using the Modification of Diet in Renal Disease (MDRD) equation than with CKD Epidemiology Collaboration (CKD-EPI) equation in the 60–75-year age group and more had reduced eGFR using CKD-EPI in the ≥80-year age group.

Conclusion

This study found that around 44.0% of people living with CKD are undiagnosed without screening, and prevalence of CKD stages 1–5 was 18.2% in participants aged >60 years. Follow-up will provide data on annual incidence, rate of CKD progression, determinants of rapid progression, and predictors of cardiovascular events.

Hypoxia-preconditioned mesenchymal stem cells prevent renal fibrosis and inflammation in ischemia-reperfusion rats

Background

Mesenchymal stem cells (MSCs) have been reported to promote the regeneration of injured tissue via their paracrine abilities, which are enhanced by hypoxic preconditioning. In this study, we examined the therapeutic efficacy of hypoxia-preconditioned MSCs on renal fibrosis and inflammation in rats with ischemia-reperfusion injury (IRI).

Methods

MSCs derived from rats and humans were incubated in 1% O₂ conditions (1%O₂ MSCs) for 24 h. After IRI, 1%O₂ MSCs or MSCs cultured under normoxic conditions (21%O₂ MSCs) were injected through the abdominal aorta. At 7 or 21 days post-injection, the rats were sacrificed and their kidneys were analyzed. In in vitro experiments, we examined whether 1%O₂ MSCs enhanced the ability to produce anti-fibrotic humoral factors using transforming growth factor (TGF)-β1-stimulated HK-2 cells incubated with conditioned medium from MSCs.

Results

Administration of rat 1%O₂ MSCs (1%O₂ rMSCs) attenuated renal fibrosis and inflammation more significantly than rat 21%O₂ MSCs. Notably, human 1%O₂ MSCs (1%O₂ hMSCs) also attenuated renal fibrosis to the same extent as 1%O₂ rMSCs. Flow cytometry showed that 1%O₂ hMSCs did not change human leukocyte antigen expression. Further in vitro experiments revealed that conditioned medium from 1%O₂ MSCs further suppressed TGF-β1-induced fibrotic changes in HK-2 cells compared with 21%O₂ MSCs. Hypoxic preconditioning enhanced vascular endothelial growth factor (VEGF) and hepatocyte growth factor (HGF) secretion. Interestingly, VEGF knockdown in 1%O₂ MSCs attenuated HGF secretion and the inhibition of TGF-β1-induced fibrotic changes in HK-2 cells. In addition, VEGF knockdown in 1%O₂ hMSCs reduced the anti-fibrotic effect in IRI rats.

Conclusions

Our results indicate that hypoxia-preconditioned MSCs are useful as an allogeneic transplantation cell therapy to prevent renal fibrosis and inflammation.