Inflammation Alters Relationship Between High-Density Lipoprotein Cholesterol and Cardiovascular Risk in Patients With Chronic Kidney Disease: Results From KNOW-CKD

Targeting Pharmacotherapies for Inflammatory and Cardiorenal Endpoints in Kidney Disease

ABSTRACT

Inflammation is an important contributor to excess cardiovascular risk and progressive renal injury in people with chronic kidney disease (CKD). Dysregulation of the innate and adaptive immune system is accelerated by CKD and results in increased systemic inflammation, a heightened local vascular inflammatory response leading to accelerated atherosclerosis, and dysfunction of the cardiac and renal endothelium and microcirculation. Understanding and addressing the dysregulated immune system is a promising approach to modifying cardiorenal outcomes in people with CKD. However, targeted pharmacotherapies adopted from trials of non-CKD and cardiorheumatology populations are only beginning to be developed and tested in human clinical trials. Pharmacotherapies that inhibit the activation of the NOD-like receptor protein 3 inflammasome and the downstream cytokines interleukin-1 and interleukin-6 are the most well-studied. However, most of the available evidence for efficacy is from small clinical trials with inflammatory and cardiorenal biomarker endpoints, rather than cardiovascular event endpoints, or from small CKD subgroups in larger clinical trials. Other pharmacotherapies that have proven beneficial for cardiorenal endpoints in people with CKD have been found to have pleiotropic anti-inflammatory benefits including statins, mineralocorticoid receptor antagonists, sodium-glucose cotransporter 2 inhibitors, and glucagon-like peptide-1 agonists. Finally, emerging therapies in CKD such as interleukin-6 inhibition, small-interfering RNA against lipoproteins, aryl hydrocarbon receptor inhibitors, and therapies adopted from the renal transplant population including mammalian target of rapamycin inhibitors and T regulatory cell promoters may have benefits for cardiorenal and inflammatory endpoints but require further investigation in clinical trials.

The 2021 KDIGO blood pressure target and the progression of chronic kidney disease: Findings from KNOW-CKD

BACKGROUND

The 2021 Kidney Disease: Improving Global Outcomes (KDIGO) clinical practice guideline for the management of blood pressure (BP) in chronic kidney disease (CKD) recommends a target systolic BP of <120 mmHg as this target can provide cardiovascular benefits. However, it remains unclear whether implementing the new BP target could improve kidney outcomes.

METHODS

The association between the 2021 KDIGO BP target and CKD progression was examined and compared with the 2012 KDIGO BP target among 1724 participants included in the KoreaN Cohort Study for Outcomes in Patients With CKD. The main exposure was the BP status categorized according to the 2012 or 2021 KDIGO guideline: (1) controlled within the 2021 target, (2) controlled within the 2012 target only, and (3) above both targets. The primary outcome was a composite kidney outcome of ≥50% decline in the estimated glomerular filtration rate from baseline or the initiation of kidney replacement therapy during the follow-up period.

RESULTS

Composite kidney outcomes occurred in 650 (37.7%) participants during the 8078 person-years of follow-up (median, 4.9 years). The incidence rates of this outcome were 55, 66.5, and 116.4 per 1000 person-years in BP controlled within the 2021 and 2012 KDIGO targets, and BP above both targets, respectively. In the multivariable cause-specific hazard model, hazard ratios for the composite outcome were 0.76 (95% confidence interval (CI), 0.60-0.95) for BP controlled within the 2021 target and 1.36 (95% CI, 1.13-1.64) for BP above both targets, compared with BP controlled within 2012 target only.

CONCLUSION

The newly lowered BP target by the 2021 KDIGO guideline was associated with improved kidney outcome compared with BP target by the 2012 KDIGO guideline.

Dyslipidemia in Patients with Chronic Kidney Disease: An Updated Overview

Dyslipidemia is a potentially modifiable cardiovascular risk factor. Whereas the recommendations for the treatment target of dyslipidemia in the general population are being more and more rigorous, the 2013 Kidney Disease: Improving Global Outcomes clinical practice guideline for lipid management in chronic kidney disease (CKD) presented a relatively conservative approach with respect to the indication of lipid lowering therapy and therapeutic monitoring among the patients with CKD. This may be largely attributed to the lack of high-quality evidence derived from CKD population, among whom the overall feature of dyslipidemia is considerably distinctive to that of general population. In this review article, we cover the characteristic features of dyslipidemia and impact of dyslipidemia on cardiovascular outcomes in patients with CKD. We also review the current evidence on lipid lowering therapy to modify the risk of cardiovascular events in this population. We finally discuss the association between dyslipidemia and CKD progression and the potential strategy to delay the progression of CKD in relation to lipid lowering therapy.

High-density lipoprotein cholesterol modifies the association between blood lead and uric acid: results from NHANES 2005-2016

BACKGROUND

The association between blood lead (PbB) and uric acid (SUA) remains unclear in US adults without a high level of lead exposure. Additionally, the effects of high-density lipoprotein cholesterol (HDL-C) modifying this association are still unclear. Therefore, this study aims to assess the effect of modification of high-density lipoprotein cholesterol on the association between PbB and SUA.

METHOD

This research analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2016. Through several screenings, 18,578 participants over the age of 20 were eligible for the analysis. Multivariable linear regression was used to evaluate the association between PbB and SUA. By having stratified participants based on the HDL-C intake category (low HDL-C intake < 50 mg/dl; high HDL-C intake ≥ 50 mg/dl), effect modification by HDL-C was assessed through a likelihood ratio test between PbB and SUA.

RESULT

Multivariable linear regression indicated that PbB positively affects SUA (β = 0.19, 95% CI 0.16-0.22). The relationship between PbB and SUA was different in the low and high HDL-C intake group (β 0.12 95% Cl 0.08-0.16 vs. β 0.26 95% Cl 0.22 ~ - 0.30). Furthermore, high-density lipoprotein cholesterol significantly modified the relationship between PbB and SUA in all models which indicates that the interaction of lead exposure and HDL-C is more dangerous than the sum of the individual effects.

CONCLUSIONS

Our study shows that high-density lipoprotein cholesterol and blood lead have an interactive effect on increasing uric acid, which may have great importance for clinical medication.

Serum triglycerides level is independently associated with renal outcomes in patients with non-dialysis chronic kidney disease: Results from KNOW-CKD study

To investigate whether high serum triglycerides (TG) level is associated with adverse renal outcomes in patients with non-dialysis chronic kidney disease (CKD), a total of 2,158 subjects from a prospective cohort study (Korean Cohort Study for Outcome in Patients With Chronic Kidney Disease) were divided into the quartile by serum TG level. The primary outcomes were composite renal events, which is defined as a composite of decline of kidney function (the first occurrence of > 50% decline of estimated glomerular filtration rate or doubling of serum creatinine from the baseline) or onset of end-stage renal disease (initiation of dialysis or kidney transplantation). During the median follow-up of 6.940 years, the cumulative incidence of composite renal event was significantly differed by serum TG level in Kaplan-Meier curve analysis (P < 0.001, by Log-rank test). Cox regression analysis demonstrated that, compared to that of the 1st quartile, the risk of composite renal event was significantly higher in the 4th quartile (adjusted hazard ratio 1.433, 95% confidence interval 1.046 to 1.964). The association between high serum TG level and adverse renal outcome remained consistent in the cause-specific hazard model. Subgroup analyses revealed that the association is modified by age, estimated glomerular filtration rate, and spot urine albumin-to-creatinine ratio. In conclusion, high serum TG level is independently associated with adverse renal outcomes in patients with non-dialysis CKD. Interventional studies are warranted to determine whether lowering serum TG levels may alter the natural course of CKD.

Non-High-Density Lipoprotein Cholesterol and Progression of Chronic Kidney Disease: Results from the KNOW-CKD Study

As the relation between serum non-high-density lipoprotein cholesterol (nHDL) level and renal outcomes has never been investigated in patients with non-dialysis chronic kidney disease (CKD) yet, we here aimed to unveil the association of nHDL with CKD progression. A total of 2152 patients with non-dialysis CKD at stages 1 to 5 from the KNOW-CKD study were categorized into the tertile (i.e., 1st (T1), 2nd (T2), and 3rd (T3) tertiles) by nHDL, and were prospectively analyzed. The primary outcome was the composite renal event, defined as a composite of decline of kidney function or onset of end-stage renal disease. Kaplan–Meier survival curves analysis demonstrated that the cumulative incidence of the composite renal event was significantly increased in T1 and T3, compared to T2 (p = 0.028, by Log-rank test). Cox regression analysis revealed that both T1 (adjusted hazard ratio 1.309, 95% confidence interval 1.074–1.595) and T3 (adjusted hazard ratio 1.272, 95% confidence interval 1.040–1.556) are associated with significantly increased risk of a composite renal event, compared to T2. The restricted cubic spline plot demonstrated a non-linear, U-shaped association between nHDL and the risk of a composite renal event. In conclusion, both low and high serum nHDL levels are associated with increased risk of CKD progression.

Non-High-Density Lipoprotein Cholesterol and Cardiovascular Outcomes in Chronic Kidney Disease: Results from KNOW-CKD Study

As non-high-density lipoprotein cholesterol (non-HDL-C) levels account for all atherogenic lipoproteins, serum non-HDL-C level has been suggested to be a marker for cardiovascular (CV) risk stratification. Therefore, to unveil the association of serum non-HDL-C levels with CV outcomes in patients with non-dialysis chronic kidney disease (ND-CKD), the patients at stages 1 to 5 (n = 2152) from the Korean Cohort Study for Outcomes in Patients with Chronic Kidney Disease (KNOW-CKD) were prospectively analyzed. The subjects were divided into quintiles by serum non-HDL-C level. The primary outcome was a composite of all-cause death or non-fatal CV events. The median duration of follow-up was 6.940 years. The analysis using the Cox proportional hazard model unveiled that the composite CV event was significantly increased in the 5th quintile (adjusted hazard ratio 2.162, 95% confidence interval 1.174 to 3.981), compared to that of the 3rd quintile. A fully adjusted cubic spline model depicted a non-linear, J-shaped association between non-HDL-C and the risk of a composite CV event. The association remained robust in a series of sensitivity analyses, including the analysis of a cause-specific hazard model. Subgroup analyses reveled that the association is not significantly altered by clinical conditions, including age, gender, body mass index, estimated glomerular filtration rate, and albuminuria. In conclusion, high serum non-HDL-C level increased the risk of adverse CV outcomes among the patients with ND-CKD. Further studies are warranted to define the optimal target range of non-HDL-C levels in this population.

OUP accepted manuscript

Introduction

Inflammation and oxidative stress contribute to the disproportionate burden of cardiovascular disease (CVD) in chronic kidney disease (CKD). Disordered catabolism of tryptophan via the kynurenine and indole pathways is linked to CVD in both CKD and dialysis patients. However, the association between specific kynurenine and indole metabolites with subclinical CVD and time to new cardiovascular (CV) events in CKD has not been studied.

Methods

We measured kynurenine and indole pathway metabolites using targeted mass spectrometry in a cohort of 325 patients with moderate to severe CKD and a median follow-up of 2 years. Multiple linear regression and Cox regression analyses were used to assess the relationship between these tryptophan metabolites and subclinical CVD, including calcium scores, carotid intima-media thickness and time to new cardiovascular (CV) events.

Results

Elevated quinolinic and anthranilic acids were independently associated with reduced time to new CVD [hazard ratio (HR) 1.28, P = .01 and HR 1.02, P = .02, respectively). Low tryptophan levels were associated with reduced time to new CV events when adjusting for demographics and CVD history (HR 0.30, P = .03). Low tryptophan levels were also associated with aortic calcification in a fully adjusted linear regression model (β = −1983, P = .006). Similarly, high levels of several kynurenine pathway metabolites predicted increased coronary, aortic and composite calcification scores.

Conclusions

We demonstrate the association of kynurenine pathway metabolites, and not indole derivatives, with subclinical and new CV events in an advanced CKD cohort. Our findings support a possible role for altered tryptophan immune metabolism in the pathogenesis of CKD-associated atherosclerosis.

Dyslipidemia, Diabetes and Atherosclerosis: Role of Inflammation and ROS-Redox-Sensitive Factors

The prevalence of diabetes is growing at an alarming rate with increased disability, morbidity, and often premature mortality because of the various complications of this disorder. Chronic hyperglycemia, dyslipidemia, and other metabolic alterations lead to the development and progression of macro- and microvascular complications of diabetes including cardiovascular, retinal and kidney disease. Despite advances in glucose and lipid lowering treatments, a large number of diabetic individuals develop one or more types of these complications, ultimately leading to end-organ damage over the time. Atherosclerosis is the major macro-vascular complications of diabetes and the primary underlying cause of cardiovascular disease (CVD) posing heavy burden on the health care system. In this review, we discuss the involvement of dyslipidemia in the progression of atherosclerosis by activating the pro-inflammatory cytokines and oxidative stress-related factors. In addition, we also provide information on various pharmacological agents that provides protection against diabetic atherosclerosis by reducing inflammation and oxidative stress.