What happens to the heart in chronic kidney disease?

Cardiac Magnetic Resonance Imaging Findings in Patients With Chronic Kidney Disease and End-Stage Kidney Disease: A Systematic Review and Meta-Analysis

In this systematic review and meta-analysis, we explored the utilization of cardiac magnetic resonance imaging (CMR) to detect fibrotic changes secondary to uremic cardiomyopathy during the early stages of chronic kidney disease (CKD) and in patients with end-stage kidney disease (ESKD). Uremic myocardial fibrosis can lead to arrhythmia and heart failure, and it is important to detect these changes. CMR offers a noninvasive way to characterize the severity of cardiac remodeling. A comprehensive search of multiple electronic databases was conducted. Studies were divided according to scanner field strength (1.5 or 3 Tesla). The random effects model was used to calculate the pooled mean, 95% confidence interval (CI), standard error, and standardized mean difference (SMD). The I2 statistic was used to assess the heterogeneity between study-specific estimates. The search retrieved 779 studies. From these, 20 studies met the inclusion criteria and had 642 CKD patients (mean age of 56.8 years; 65.2% males; mean estimated glomerular filtration rate (eGFR) of 33 mL/min/1.73 m2) and 658 ESKD patients on dialysis (mean age of 55.6 years; 63.3% males; mean dialysis duration of 3.47 years). CKD patients had an increased left ventricular mass index (LVMi) compared to controls, with an SMD of 0.37 (95% CI: 0.20-0.54; I2 0%; p-value <0.05). ESKD patients also had increased LVMi compared to controls, SMD 0.88 (95% CI: 0.35-1.41; I2 79.1%; p-value 0.001). Myocardial fibrosis assessment using T1 mapping showed elevated values; the SMD of native septal T1 values between CKD and controls was 1.099 (95% CI: 0.73-1.46; I2 33.6%; p-value <0.05), and the SMD of native septal T1 values between ESKD patients and controls was 1.12 (95% CI: 0.85-1.38; I2 33.69%; p-value <0.05). In conclusion, patients with CKD and ESKD with preserved left ventricular ejection fraction (LVEF) have higher LVMi and T1 values, indicating increased mass and fibrosis. T1 mapping can be used for the early detection of cardiomyopathy and as a risk stratification tool. Large, randomized trials are needed to confirm these findings and determine the effect of long-term dialysis on cardiac fibrosis.

Defining Biventricular Abnormalities by Cardiac Magnetic Resonance in Pre-Dialysis Patients with Chronic Kidney Disease

Introduction

The aim of the study was to investigate biventricular structural and functional abnormalities in pre-dialysis patients across stages of chronic kidney disease (CKD) by cardiac magnetic resonance (CMR).

Methods

Fifty-one CKD patients with CMR exams were retrospectively analyzed. Patients were divided into three groups according to estimated glomerular filtration rate (eGFR): CKD 1 group (patients with normal eGFR≥90 mL/min/1.73 m2, n = 20), CKD 2-3 group (patients with eGFR< 90 to ≥30 mL/min/1.73 m2, n = 14), and CKD 4-5 group (patients with eGFR<30 mL/min/1.73 m2, n = 17). Twenty-one age- and sex-matched healthy controls (HC) were recruited. CMR-derived left ventricular (LV) and right ventricular (RV) structural and functional measures were compared. Association between CMR parameters and clinical measures was assessed.

Results

There was an increasing trend in RV mass index (RVMi) and LV mass index (LVMi) with the occurrence and development of CKD from HC group to CKD 4-5 group although no significant difference was observed between CKD 1 group and HC group. LV global radial strain and LV global circumferential strain dropped and native T1 value elevated significantly in CKD 4-5 group compared with the other three groups (all p < 0.05), while RV strain measures, RV ejection fraction, and LV ejection fraction showed no significant difference among 4 groups (all p > 0.05). Elevated LV end-diastolic volume index (β = 0.356, p = 0.016) and RV end-systolic volume index (β = 0.488, p = 0.001) were independently associated with RVMi. Increased systolic blood pressure (β = 0.309, p = 0.004), LV end-systolic volume index (β = 0.633, p < 0.001), and uric acid (β = 0.261, p = 0.013) were independently associated with LVMi. Meanwhile, serum phosphorus (β = 0.519, p = 0.001) was independently associated with native T1 value.

Conclusion

In pre-dialysis CKD patients, left and right ventricular remolding has occurred. RVMi and LVMi were the first changed CMR indexes in the development of CKD when eGFR began to drop. Because fluid volume overload was the independent risk factor for RVMi and LVMi increase, reasonable controlling fluid volume overload may slow down the progression of biventricular remolding and may reduce related cardiovascular disease risk.

Drug Testing for Chronic Kidney Disease and Diabetes in Animals versus Humans: A Comparative Analysis of Study Designs and Reporting Qualities

INTRODUCTION

Diabetes is a highly prevalent accelerator or even cause of chronic kidney disease imposing a large unmet medical need at the global scale. Massive research activities continue to be in search of a cure but the yield of the classical bench-to-bedside research approach has been low. We speculated that a significant mismatch in design and quality of animal and clinical studies in this domain is a hurdle for translation.

METHODS

We performed a meta-analysis of matched pairs of animal and human studies that tested the efficacy of distinct drug interventions for diabetic kidney disease (DKD). We reviewed study designs and reporting quality of such studies over the last decade according to the standards listed in the CONSORT and ARRIVE recommendations, respectively.

RESULTS

We noted a wide diversity in the study designs of animal studies in terms of diabetes induction. Major mismatches with the respective human studies referred to age and sex distribution, comorbidities, stage of the kidney disease, and selection of primary endpoints. Usually, treatment was initiated before onset of kidney disease without any standard of care as a background therapy. The reporting quality of animal studies was poor for randomization procedures, blinding, sample size calculation for a prespecified primary endpoint or the safety analysis. Reporting quality of clinical studies had deficits in trial design-, recruitment-, allocation-, and outcome-related aspects.

CONCLUSION

Bench-to-bedside translation in the domain of DKD suffers from major deficits in the design of experimental studies in view of the projected clinical trials as well as from significant deficits in the reporting quality in preclinical and clinical studies.

Myocardial Cytoskeletal Adaptations in Advanced Kidney Disease

Background The myocardial cytoskeleton functions as the fundamental framework critical for organelle function, bioenergetics and myocardial remodeling. To date, impairment of the myocardial cytoskeleton occurring in the failing heart in patients with advanced chronic kidney disease has been largely undescribed. Methods and Results We conducted a 3-arm cross-sectional cohort study of explanted human heart tissues from patients who are dependent on hemodialysis (n=19), hypertension (n=10) with preserved renal function, and healthy controls (n=21). Left ventricular tissues were subjected to pathologic examination and next-generation RNA sequencing. Mechanistic and interference RNA studies utilizing in vitro human cardiac fibroblast models were performed. Left ventricular tissues from patients undergoing hemodialysis exhibited increased myocardial wall thickness and significantly greater fibrosis compared with hypertension patients (P<0.05) and control (P<0.01). Transcriptomic analysis revealed that the focal adhesion pathway was significantly enriched in hearts from patients undergoing hemodialysis. Hearts from patients undergoing hemodialysis exhibited dysregulated components of the focal adhesion pathway including reduced β-actin (P<0.01), β-tubulin (P<0.01), vimentin (P<0.05), and increased expression of vinculin (P<0.05) compared with controls. Cytoskeletal adaptations in hearts from the hemodialysis group were associated with impaired mitochondrial bioenergetics, including dysregulated mitochondrial dynamics and fusion, and loss of cell survival pathways. Mechanistic studies revealed that cytoskeletal changes can be driven by uremic and metabolic abnormalities of chronic kidney disease, in vitro. Furthermore, focal adhesion kinase silencing via interference RNA suppressed major cytoskeletal proteins synergistically with mineral stressors found in chronic kidney disease in vitro. Conclusions Myocardial failure in advanced chronic kidney disease is characterized by impairment of the cytoskeleton involving disruption of the focal adhesion pathway, mitochondrial failure, and loss of cell survival pathways.

Left ventricular mass regression, all-cause and cardiovascular mortality in chronic kidney disease: a meta-analysis

Background

Cardiovascular disease is an important driver of the increased mortality associated with chronic kidney disease (CKD). Higher left ventricular mass (LVM) predicts increased risk of adverse cardiovascular outcomes and total mortality, but previous reviews have shown no clear association between intervention-induced LVM change and all-cause or cardiovascular mortality in CKD.

Methods

The primary objective of this meta-analysis was to investigate whether treatment-induced reductions in LVM over periods ≥12 months were associated with all-cause mortality in patients with CKD. Cardiovascular mortality was investigated as a secondary outcome. Measures of association in the form of relative risks (RRs) with associated variability and precision (95% confidence intervals [CIs]) were extracted directly from each study, when reported, or were calculated based on the published data, if possible, and pooled RR estimates were determined.

Results

The meta-analysis included 42 trials with duration ≥12 months: 6 of erythropoietin stimulating agents treating to higher vs. lower hemoglobin targets, 10 of renin-angiotensin-aldosterone system inhibitors vs. placebo or another blood pressure lowering agent, 14 of modified hemodialysis regimens, and 12 of other types of interventions. All-cause mortality was reported in 121/2584 (4.86%) subjects in intervention groups and 168/2606 (6.45%) subjects in control groups. The pooled RR estimate of the 27 trials ≥12 months with ≥1 event in ≥1 group was 0.72 (95% CI 0.57 to 0.90, p = 0.005), with little heterogeneity across studies. Directionalities of the associations in intervention subgroups were the same. Sensitivity analyses of ≥6 months (34 trials), ≥9 months (29 trials), and >12 months (10 trials), and including studies with no events in either group, demonstrated similar risk reductions to the primary analysis. The point estimate for cardiovascular mortality was similar to all-cause mortality, but not statistically significant: RR 0.67, 95% CI 0.39 to 1.16.

Conclusions

These results suggest that LVM regression may be a useful surrogate marker for benefits of interventions intended to reduce mortality risk in patients with CKD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02666-1.

Clinical and dialysis-related characteristics of extremely long-term hemodialysis survivors: Three case reports

More than 40-year hemodialysis survivors are living evidence of the achievements of hemodialysis therapy. We present the case reports of three patients treated by chronic hemodialysis for 47 (Patient 1), 43 (Patient 2), and 42 years (Patient 3) from a single center. These patients possess characteristics that were already shown to be associated with improved long-term survival: initiation of hemodialysis at a young age, absence of diabetes, and a relatively low and stable body weight with good nutritional status. Although all of them underwent complications of long-term hemodialysis treatment, they lived (Patient 3), or are still living (Patients 1 and 2), an independent and full life. Their hemodialysis prescriptions included long sessions with a moderate blood flow rate, state-of-the-art hemodialysis technology, vascular access surgeries and care provided by nephrologists, good overall management of chronic kidney disease, and preventive measures and/or immediate action in case of cardiovascular disease.

Polymorphisms in the 5’-UTR region of IL-10RA gene are associated with chronic kidney disease

Chronic kidney disease (CKD), characterized by the progressive, irreversible loss of kidney function, has been a significant socioeconomic burden. Thus, identifying potential treatment targets and incipient biological risk indicators for CKD prediction is crucial. Recently several studies revealed that IL-10, IL-10RA, and IL-10RB genes were involved in the development of vascular complications in hypertension and stroke. The purpose of this study was to evaluate the association between CKD and IL-10, IL-10RA, and IL-10RB gene polymorphisms in the Korean population. Ninety-two CKD patients and 312 control subjects participated in the study. Blood samples were drawn for biochemical measurements and genetic polymorphism analysis. To analyze the genotypes of each single nucleotide polymorphism (SNP), PCR products were sequenced by a DNA analyzer. The four SNPs of the IL-10RA gene showed significant associations between CKD and the control group in the codominant1 (rs2228054, rs2228055, and rs9610, OR = 0.48, 95% CI = 0.28–0.82, p = 0.007; rs2256111, OR = 0.49, 95% CI = 0.29–0.83, p = 0.008, respectively), dominant (rs2228054, rs2228055, and rs9610, OR = 0.59, 95% CI = 0.36–0.95, p = 0.028; rs2256111, OR = 0.60, 95% CI = 0.38–0.97, p = 0.037, respectively), and over-dominant model (rs2228054 and rs2228055, OR = 0.47, 95% CI = 0.28–0.79, p = 0.0034; rs9610, OR = 0.48, 95% CI = 0.29–0.80, p = 0.0037; rs2256111, OR = 0.49, 95% CI = 0.29–0.80, p = 0.0039). The four SNPs of IL-10 showed significant associations with the estimated glomerular filtration rate (eGFR) and C-reactive protein (CRP), with the minor homozygote genotype of each SNP associated with lower eGFRs and decreased CRP levels ( p < 0.05, p = 0.001, respectively). The two SNPs of IL-10RA showed significant associations with the CRP levels ( p < 0.05). The two SNPs of IL-10RB were significantly associated with the eGFR, with the minor homozygote genotype of each SNP associated with lower eGFRs ( p < 0.01). Our results show that IL-10RA gene variants are associated with CKD development. Additionally, this study suggests that SNPs of IL-10RA were associated with CRP levels in CKD.

Cardiovascular Functional Changes in Chronic Kidney Disease: Integrative Physiology, Pathophysiology and Applications of Cardiopulmonary Exercise Testing

The development of cardiovascular disease during renal impairment involves striking multi-tiered, multi-dimensional complex alterations encompassing the entire oxygen transport system. Complex interactions between target organ systems involving alterations of the heart, vascular, musculoskeletal and respiratory systems occur in Chronic Kidney Disease (CKD) and collectively contribute to impairment of cardiovascular function. These systemic changes have challenged our diagnostic and therapeutic efforts, particularly given that imaging cardiac structure at rest, rather than ascertainment under the stress of exercise, may not accurately reflect the risk of premature death in CKD. The multi-systemic nature of cardiovascular disease in CKD patients provides strong rationale for an integrated approach to the assessment of cardiovascular alterations in this population. State-of-the-art cardiopulmonary exercise testing (CPET) is a powerful, dynamic technology that enables the global assessment of cardiovascular functional alterations and reflects the integrative exercise response and complex machinery that form the oxygen transport system. CPET provides a wealth of data from a single assessment with mechanistic, physiological and prognostic utility. It is an underutilized technology in the care of patients with kidney disease with the potential to help advance the field of cardio-nephrology. This article reviews the integrative physiology and pathophysiology of cardio-renal impairment, critical new insights derived from CPET technology, and contemporary evidence for potential applications of CPET technology in patients with kidney disease.

AMY1 diploid copy number among end-stage renal disease patients

PURPOSE

The salivary amylase gene (AMY1) copy number variation (CNV) is increased as a human adaptation to starch-enriched nutritional patterns. The purpose of this study was to evaluate the relationship between AMY1 CNV, dietary starch consumption, and anthropometric indices among a known population with elevated cardiovascular risk, being end-stage renal disease (ESRD) patients.

METHODS

A total of 43 ESRD patients were recruited based on the following inclusion criteria: being (1) adults, (2) on hemodialysis for more than 3 months, (3) able to communicate effectively, and (4) willing to participate. Anthropometric measurements were performed, dietary intake was recorded via food-frequency questionnaires, and AMY1 CNV was quantified in blood samples DNA via real-time PCR.

RESULTS

Median AMY1 CNV was 4.0 (2.0-17.0). A total of 21 patients had an even, and 22 had an odd AMY1 copy number (CN). Independent samples t tests revealed that AMY1-odd diploid CN is associated with increased body weight, waist and hip circumferences, and fat mass compared to the respective even diploid CN carrier group. No differences were observed for BMI or nutritional intake. Multiple regression analysis revealed that AMY1-odd diploid CN was positively associated with increased hip circumference (ß = 7.87, 95% CI = 0.34 to 15.39) and absolute fat mass (ß = 6.66, 95% CI = 0.98 to 12.34); however, after applying the Bonferroni correction for multiplicity, all regression analyses lost their significance.

CONCLUSIONS

AMY1-odd diploid CN appears to be associated with selected adiposity variables among hemodialysis patients. However, more research is needed to verify this finding in this population with known increased cardiovascular risk.