Is systemic inflammation of hemodialysis patients improved with the use of enalapril? Results of a randomized, double-blinded, placebo-controlled clinical trial

Randomized, double-blinded, controlled clinical trial of the effect of captopril, telmisartan and their combination on systemic inflammation of patients on hemodialysis

To evaluate individual and combined effect of captopril and telmisartan on systemic inflammation markers of hemodialysis (HD) patients. Randomized, double-blinded, controlled clinical trial. Patients on HD at least 2 months, with arteriovenous fistula, were randomly allocated to groups: (1) captopril/placebo (N 13); (2) telmisartan/placebo (N 13); (3) captopril + telmisartan (N 12); or (4) placebo/placebo (N 12). During 3 months, patients received oral drugs as follows: captopril 50 mg/day, telmisartan 80 mg/day or placebo. Patients excluded if they had conditions or were on drugs potentially influencing on inflammation. Clinical and biochemical evaluations were performed monthly. Serum tumor necrosis factor alpha (TNFα), interleukin 6 (IL-6), and C-reactive protein (CRP) were measured at 0, 1 and 3 months. Baseline, demographic, clinical and biochemical variables were comparable between groups. Baseline versus final inflammatory markers were: captopril/placebo TNFα, 2.47 (0.1-4.5) versus 1.73 (0.3-3.8) pg/ml; IL-6, 17.03 (7.2-23) versus 7.90 (0.7-19) pg/ml; CRP, 4.21 (1.6-18) versus 5.9 (3.0-28) mg/l; telmisartan/placebo TNFα, 3.03 (2.3-4.6) versus 1.70 (1.2-2.0) pg/ml; IL-6, 14.10 (5.5-23) versus 9.85 (6.2-13) pg/ml; CRP, 5.74 (2.1-13) versus 10.60 (1.5-27) mg/l; captopril + telmisartan TNFα, 1.43 (0.7-5.4) versus 0.40 (0.1-2.1) pg/ml; IL-6, 10.05 (4.9-23) versus 4.00 (0.7-7.7) pg/ml (p < 0.05); CRP, 3.26 (0.7-12) versus 2.83 (0.6-6.5) mg/l; placebo/placebo TNFα, 3.13 (1.6-5.6) versus 1.64 (1.6-2.3) pg/ml; IL-6, 8.12 (5.4-16) versus 7.60 (2.4-15) pg/ml; CRP, 5.23 (1.9-16) versus 3.13 (1.5-18) mg/l. Monotherapy with captopril or telmisartan display a trend, but their combined treatment significantly decreased serum levels of IL-6. No remarkable changes on TNFα and CRP were observed.

Effect of the Renin-Angiotensin System Inhibitors on Inflammatory Markers: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To synthesize more conclusive evidence on the anti-inflammatory effects of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs).

METHODS

PubMed, Scopus, and Embase were searched from inception until March 1, 2021. We included randomized controlled trials (RCTs) that assessed the effect of ACEIs or ARBs, compared with placebo, on any of the following markers: C-reactive protein (CRP), interleukin 6 (IL-6), or tumor necrosis factor α (TNF-α). Mean changes in the levels of these markers were pooled as a weighted mean difference (WMD) with a 95% CI.

RESULTS

Thirty-two RCTs (n=3489 patients) were included in the final analysis. Overall pooled analysis suggested that ACEIs significantly reduced plasma levels of CRP (WMD, -0.54 [95% CI, -0.88 to -0.21]; P=.002; I²=96%), IL-6 (WMD, -0.84 [95% CI, -1.03 to -0.64]; P<.001; I²=0%), and TNF-α (WMD, -12.75 [95% CI, -17.20 to -8.29]; P<.001; I²=99%). Moreover, ARBs showed a significant reduction only in IL-6 (WMD, -1.34 [95% CI, -2.65 to -0.04]; P=.04; I²=85%) and did not significantly affect CRP (P=.15) or TNF-α (P=.97) levels. The lowering effect of ACEIs on CRP levels remained significant with enalapril (P=.006) and perindopril (P=.01) as well as with a treatment duration of less than 24 weeks (WMD, -0.67 [95% CI, -1.07 to -0.27]; P=.001; I²=94%) and in patients with coronary artery disease (WMD, -0.75 [95% CI, -1.17 to -0.33]; P<.001; I²=96%).

CONCLUSION

Based on this meta-analysis, ACEIs showed a beneficial lowering effect on CRP, IL-6, and TNF-α, whereas ARBs were effective as a class in reduction of IL-6 only.

Soluble Triggering Receptor on Myeloid Cell-1 and its Predictive Factors in Patients With End-Stage Kidney Disease on Hemodialysis

Triggering receptor expressed on myeloid cells (TREM)-1 is a potent and early amplifier of the inflammatory response expressed on neutrophils and monocytes/macrophages. TREM-1, and its soluble form (sTREM-1), are increased in sepsis and other noninfectious inflammatory conditions. However, virtually no data are available in kidney disease. To determine serum sTREM-1 and its associated variables in patients on hemodialysis (HD), cross-sectional study including 264 HD patients and 148 controls. sTREM-1 was measured by quantitative sandwich enzyme immunoassay; soluble tumor necrosis factor receptor-1 (sTNF-R1), interleukin-6 (IL-6), and C-reactive protein (CRP) were also measured. All inflammation markers were significantly higher in HD patients than controls. Median (IQR) sTREM-1 was 1,006 (613-1,650) pg/mL but undetectable in controls. Considering only HD patients, sTREM-1 was positively correlated with IL-6 (r = 0.19, p = 0.008), and its levels were significantly higher in patients with arteriovenous fistula than in those with temporary catheter (1,226 vs. 743 pg/mL), in patients with 3 HD sessions/week than in those with 2 sessions/week (1,150 vs. 646 pg/mL), and in patients with >1 year on HD than in those with ≤1 year (1,100 vs. 948 pg/mL), whereas they were not different regarding age or presence of infection. Serum sTREM-1, sTNF-R1, IL-6, and CRP were higher in HD patients compared to controls. In HD patients, sTREM-1 displayed higher levels in individuals with arteriovenous fistula, 3 sessions/week and longer vintage, but not in those with infection or older age; in multivariate analysis, only the first two variables significantly predicted higher sTREM-1 levels.

Inflammation in Renal Diseases: New and Old Players

Inflammation, a process intimately linked to renal disease, can be defined as a complex network of interactions between renal parenchymal cells and resident immune cells, such as macrophages and dendritic cells, coupled with recruitment of circulating monocytes, lymphocytes, and neutrophils. Once stimulated, these cells activate specialized structures such as Toll-like receptor and Nod-like receptor (NLR). By detecting danger-associated molecules, these receptors can set in motion major innate immunity pathways such as nuclear factor ĸB (NF-ĸB) and NLRP3 inflammasome, causing metabolic reprogramming and phenotype changes of immune and parenchymal cells and triggering the secretion of a number of inflammatory mediators that can cause irreversible tissue damage and functional loss. Growing evidence suggests that this response can be deeply impacted by the crosstalk between the kidneys and other organs, such as the gut. Changes in the composition and/or metabolite production of the gut microbiota can influence inflammation, oxidative stress, and fibrosis, thus offering opportunities to positively manipulate the composition and/or functionality of gut microbiota and, consequentially, ameliorate deleterious consequences of renal diseases. In this review, we summarize the most recent evidence that renal inflammation can be ameliorated by interfering with the gut microbiota through the administration of probiotics, prebiotics, and postbiotics. In addition to these innovative approaches, we address the recent discovery of new targets for drugs long in use in clinical practice. Angiotensin II receptor antagonists, NF-ĸB inhibitors, thiazide diuretics, and antimetabolic drugs can reduce renal macrophage infiltration and slow down the progression of renal disease by mechanisms independent of those usually attributed to these compounds. Allopurinol, an inhibitor of uric acid production, has been shown to decrease renal inflammation by limiting activation of the NLRP3 inflammasome. So far, these protective effects have been shown in experimental studies only. Clinical studies will establish whether these novel strategies can be incorporated into the arsenal of treatments intended to prevent the progression of human disease.

Long-term effects of angiotensin II blockade with irbesartan on inflammatory markers in hemodialysis patients: A randomized double blind placebo controlled trial (SAFIR study)

INTRODUCTION

Low-grade chronic inflammation is common in hemodialysis (HD) patients. Previous studies suggest an anti-inflammatory effect of angiotensin II receptor blocker (ARB) treatment. The aim of this study was to compare the effect of ARB vs. placebo on plasma concentrations of inflammatory markers in HD patients.

METHODS

Adult HD patients were randomized for double-blind treatment with the ARB irbesartan 150-300 mg/day or placebo. At baseline, 1 week, 3, 6, 9, and 12 months plasma high sensitivity C-reactive protein (hsCRP), interleukin (IL)-1β, IL-6, IL-8, IL-18, and transforming growth factor-β (TGF-β) were measured using Luminex and enzyme-linked immunosorbent assay (ELISA) technology.

FINDINGS

Eighty-two patients were randomized (placebo/ARB: 41/41). The groups did not differ in initial levels of any of the inflammatory markers (placebo/ARB median(range)): hsCRP 3.3(0.2-23.4)/2.7(0.2-29.6) μg/mL; IL-1β 1.1(0.0-45.9)/1.1(0.0-7.2) pg/mL; IL-6 10(1-90)/12(1-84) pg/mL; IL-8 31(9-134)/34(5-192) pg/mL; IL-18 364(188-1343)/377(213-832) pg/mL; TGF-β 3.2(0.8-13.9)/3.6(1.3-3.8) ng/mL. Overall, there was no significant difference in hsCRP, IL-6, IL-8, and TGF-β between placebo and ARB-treated patients during the study period, and hsCRP, IL-6, IL-8, and TGF-β were relatively stable during the study period (P ≥ 0.18 in all tests for parallel curves, equal levels, and constant levels). The IL-1β level was slightly different in the two groups over time, but not significantly (P = 0.09 in test for parallel curves) and it was also relatively stable during the study period (P ≥ 0.49 in tests for equal levels and constant level). IL-18 was the only inflammatory marker which was not constant during the study period (P = 0.001 in test for constant level), but there was no significant difference between placebo and ARB-treated (P ≥ 0.51 in tests for parallel curves and equal levels).

DISCUSSION

Inflammatory biomarkers were neither acutely, nor in the long-term significantly affected by the ARB irbesartan. Our findings suggest that ARB treatment in HD patients does not offer protective anti-inflammatory effects.

Pentoxifylline decreases serum levels of tumor necrosis factor alpha, interleukin 6 and C-reactive protein in hemodialysis patients: results of a randomized double-blind, controlled clinical trial

AIM

The aim of this study was to compare the effect of pentoxifylline versus placebo on serum concentrations of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6) and C-reactive protein (CRP) of hemodialysis (HD) patients.

METHODS

This is a randomized double-blind, controlled clinical trial. HD patients without infection or drugs with anti-inflammatory effect were randomly allocated to a study (n = 18, pentoxifylline 400 mg/day) or control (n = 18, placebo) group; all patients had arteriovenous fistula. Besides clinical and laboratory monthly assessments, serum TNF-α and IL-6 (ELISA) and CRP (nephelometry) were measured at 0, 2 and 4 months.

RESULTS

All the inflammation markers significantly (P < 0.05) decreased in the pentoxifylline group: TNF-α [baseline 0.4 (0-2) versus final 0 (0-0) pg/mL], IL-6 [baseline 9.4 (5-14) versus final 2.9 (2-5) pg/mL] and CRP [baseline 7.1 (3-20) versus final 2.6 (1-8) mg/L], whereas no significant changes were observed in the placebo group: TNF-α [baseline 0 (0-0) versus final 1.2 (0-4) pg/mL], IL-6 [baseline 8.0 (5-11) versus final 8.7 (4-11) pg/mL] and CRP [baseline 4.5 (2-9) versus final 3.8 (3-23) mg/L].

CONCLUSIONS

Pentoxifylline significantly decreased serum concentrations of TNF-α, IL-6 and CRP compared to placebo. Pentoxifylline could be a promising and useful strategy to reduce the systemic inflammation frequently observed in patients on HD.

Inhibition of NF-κB-induced inflammatory responses by angiotensin II antagonists in aged rat kidney

In this study, we explored the mechanisms by which the angiotensin converting enzyme inhibitor (ACEI), enalapril, and the Ang II receptor blocker (ARB), losartan suppress oxidative stress and NF-κB activation-induced inflammatory responses in aged rat kidney. The experimentations were carried out utilizing aged (24-month-old) Brown Norway×Fischer 344 (F1) male rats which were randomized into 3 groups and administered enalapril (40 mg/kg), losartan (30 mg/kg) or placebo for 6 months (daily p.o.). The level of reactive species (RS), peroxynitrite (ONOO(-)), GSH/GSSG and lipid peroxidation were measured. The activity of the pro-inflammatory transcription factor NF-κB, and gene expression of proteins in upstream signaling cascades were measured by electro-mobility shift assay (EMSA) and Western blotting. Enalapril and losartan differentially attenuated redox imbalance and the redox-sensitive transcription factor, the NF-κB pathway. Furthermore, stimulation of the NF-κB activation pathway by phosphorylation of p65 was attenuated by both compounds. Moreover, mediation of phosphorylation of p65 by phosphorylation of IκB kinase αβ (IKKαβ) and mitogen- and stress-activated protein kinase-1 (MSK-1), were also inhibited by enalapril and losartan. Finally, both compounds also lowered expression of NF-κB-dependent inflammatory genes, such as cyclooxygenase-2 (COX-2), and inducible NO synthase (iNOS). Only losartan lowered levels of 5-lipoxygenase (5-LOX). These findings indicate that enalapril and losartan differentially suppress inflammatory responses via inhibition of oxidative stress-induced NF-κB activation in aged rat kidney.