Comparative effects of angiotensin-converting enzyme inhibition and angiotensin-receptor blockade on inflammation during hemodialysis

Effect of angiotensin-converting enzyme inhibitors versus that of angiotensin receptor blockers on survival in patients undergoing hemodialysis: a nationwide observational cohort study

BACKGROUND

This study aimed to evaluate the patient survival rates based on the use of angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor blocker (ARB) in a large cohort of patients undergoing maintenance hemodialysis (HD).

METHODS

Data from a national HD quality assessment program were used in this retrospective study. The patients were classified into four groups based on the use of renin-angiotensin system blockers (RASBs) as follows: No group, patients without a prescription of any anti-hypertensive drugs including RASBs; Other group, patients with a prescription of anti-hypertensive drugs excluding RASBs; ACEI group, patients with a prescription of an ACEI; and ARB group, patients with a prescription of an ARB.

RESULTS

The 5-year survival rates in the no, other, ACEI, and ARB groups were 68.6%, 67.8%, 70.6%, and 69.2%, respectively. The ACEI group had the best patient survival trend among the four groups. In multivariable Cox regression analyses, no differences were observed between the ACEI and ARB groups. Among young patients and patients without diabetes or heart disease, the ACEI group had the best patient survival among the four groups. However, among patients with DM or heart disease, the ARB group had the best patient survival.

CONCLUSIONS

Our study found that patients receiving ACEI and ARB had comparable survival. However, patients receiving ARB had better survival in the subgroups of patients with DM or heart disease, and patients receiving ACEI had better survival in the subgroup of young patients or patients without diabetes or heart disease.

Modulation of TNF-α, interleukin-6, and interleukin-10 by nebivolol-valsartan and nebivolol-lisinopril polytherapy in SHR rats

Antihypertensive drug therapies have demonstrated their capacity to modulate the inflammatory processes associated with hypertension, leading to improvements in disease progression. Given the prevalent use of polytherapy in treating most hypertensive patients, comprehending the time-dependent effects of combination treatments on inflammation becomes imperative. In this study, spontaneously hypertensive rats (SHR) were divided into seven groups (n = 6): (i) SHR + vehicle, (ii) SHR + nebivolol, (iii) SHR + valsartan, (iv) SHR + lisinopril, (v) SHR + nebivolol-valsartan, (vi) SHR + nebivolol-lisinopril, and (vii) WKY + vehicle. Blood pressure was measured using the tail-cuff method. Temporal alterations in inflammatory cytokines TNF-α, IL-6, and IL-10 were assessed in serum through ELISA and mRNA expression in aortic tissue via qPCR after 1, 2, and 4 weeks of treatment with nebivolol, lisinopril, valsartan, and their respective combinations. Histological alterations in the aorta were assessed. The findings indicated that combined treatments reduced systolic and diastolic blood pressure in SHR. The nebivolol and lisinopril combination demonstrated a significant decrease in IL-6 serum and mRNA expression at both 1 week and 4 weeks into the treatment. Additionally, TNF-α mRNA expression also showed a reduction with this combination at the same time points. Particularly, nebivolol-valsartan significantly decreased TNF-α serum and mRNA expression after one and four weeks of treatment. Furthermore, an elevation in serum IL-10 levels was observed with both combination treatments starting from the second week onwards. This study provides compelling evidence that concurrent administration of nebivolol with lisinopril or valsartan exerts time-dependent effects, reducing proinflammatory cytokines TNF-α and IL-6 while modifying IL-10 levels in an experimental hypertensive model.

Inflammation Resolution in the Cardiovascular System: Arterial Hypertension, Atherosclerosis, and Ischemic Heart Disease

Significance: Chronic inflammation has emerged as a major underlying cause of many prevalent conditions in the Western world, including cardiovascular diseases. Although targeting inflammation has emerged as a promising avenue by which to treat cardiovascular disease, it is also associated with increased risk of infection. Recent Advances: Though previously assumed to be passive, resolution has now been identified as an active process, mediated by unique immunoresolving mediators and mechanisms designed to terminate acute inflammation and promote tissue repair. Recent work has determined that failures of resolution contribute to chronic inflammation and the progression of human disease. Specifically, failure to produce pro-resolving mediators and the impaired clearance of dead cells from inflamed tissue have been identified as major mechanisms by which resolution fails in disease. Critical Issues: Drawing from a rapidly expanding body of experimental and clinical studies, we review here what is known about the role of inflammation resolution in arterial hypertension, atherosclerosis, myocardial infarction, and ischemic heart disease. For each, we discuss the involvement of specialized pro-resolving mediators and pro-reparative cell types, including T regulatory cells, myeloid-derived suppressor cells, and macrophages. Future Directions: Pro-resolving therapies offer the promise of limiting chronic inflammation without impairing host defense. Therefore, it is imperative to better understand the mechanisms underlying resolution to identify therapeutic targets. Antioxid. Redox Signal. 40, 292-316.

Effects of Niaoduqing granules on inflammatory response of diabetic kidney disease: A meta‑analysis

Diabetic kidney disease (DKD) is one of the most severe chronic microvascular complications of diabetes and the leading cause of end-stage kidney disease worldwide. The mechanism of inflammation underlying DKD has been attracting attention over recent years, but effective therapeutic strategies have remained elusive. Niaoduqing (NDQ) granules are one of the most commonly used drugs for the treatment of DKD in China, and it has therapeutic effects against inflammation in DKD. Therefore, the aim of the present analysis was to evaluate the inflammatory response outcomes and safety of NDQ granules for the treatment of DKD. The following databases were searched from their inception to 31st of May 2023 to obtain published accounts of relevant randomized controlled trials: China National Knowledge Infrastructure, China Science and Technology Journal, Wanfang, The Chinese Biomedicine, PubMed, Web of Science and Cochrane Library. The 'risk of bias' evaluation tool produced by the Cochrane Collaboration Handbook was used for evaluating the quality, whereas Revman software (version 5.3) was used for meta-analysis. In total, 16 studies were included into the present study according to criteria, with a total of 1,526 patients. Compared with those in the control group, the results of the meta-analysis revealed that the combination of conventional treatment and NDQ granules may further decrease C-reactive protein [standardized mean difference (SMD), -1.33; 95% confidence interval (CI), -1.76, -0.91; P<0.00001], TNF-α (SMD, -1.90; 95% CI, -2.35,-1.45; P<0.00001) and IL-6 (SMD, -1.72; 95% CI, -2.52,-0.91; P<0.0001) levels, whilst increasing the clinical effective rate (risk ratio, 1.22; 95% CI, 1.14,1.29; P<0.00001), in patients with DKD. In terms of safety, a total of 34 and 39 patients included in the intervention and in the control group, respectively, developed adverse reactions. Results from the present analysis suggest that NDQ granules may be beneficial in suppressing inflammation caused by DKD when used in combination with conventional treatment, potentially guiding future directions in clinical practice. However, further high-quality studies are needed to confirm the anti-inflammation response in the future.

Bradykinin B2 receptor blockade and intradialytic hypotension

INTRODUCTION

Intradialytic hypotension (IDH) is a common clinical complication and is associated with increased morbidity and mortality in patients undergoing maintenance hemodialysis (MHD). The pathogenesis of IDH has been attributed to the rapid reduction of plasma volume during hemodialysis and the inadequate compensatory mechanisms in response to hypovolemia, such as the lack of vasoconstriction. This may be due to the increased production of vasodilators, such as bradykinin. In this study we test the hypothesis that bradykinin B2 receptor blockade prevents intradialytic hypotension.

METHODS

We performed a post-hoc analysis of a double-blind, placebo-controlled, randomized, 2 × 2 crossover clinical trial comparing the continuous infusion of icatibant, a bradykinin B2 receptor blocker, and placebo during hemodialysis. Icatibant or placebo was infused for 30 min before and during hemodialysis in 11 patients on MHD.

RESULTS

Seven of the patients had IDH, defined as a reduction of systolic blood pressure equal to or greater than 20 mmHg during hemodialysis. Stratified analysis, based on the presence of IDH, revealed that icatibant prevented the decrease in blood pressure compared to placebo in patients with IDH [blood pressure at average nadir (2.5 h after hemodialysis): Placebo,114.3 ± 8.9 vs. icatibant, 125.6 ± 9.1 mmHg, mean ± S.E.M]. Icatibant did not affect blood pressure in the group of patients without IDH.

CONCLUSION

Bradykinin B2 receptor blocker may prevent the occurrence of IDH. Further studies should evaluate the hemodynamic effects of icatibant during hemodialysis and the symptomatology associated with IDH.

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.

The effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in critically ill patients with acute kidney injury: An observational study using the MIMIC database

Background: The safety of prescribing angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) during acute kidney injury (AKI) remains unclear. We aimed to investigate the associations of ACEI/ARB therapy in AKI with the risk of mortality, acute kidney disease (AKD), and hyperkalemia.

Methods: We conducted a retrospective monocentric study, which included patients in Massachusetts between 2008 and 2019 from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Propensity score matching was performed for the endpoint analysis. The association between ACEI/ARB therapy and mortality was assessed using Cox proportional hazards regression models. Logistic regression was used to assess the risk of AKD and hyperkalemia.

Results: Among the 19,074 individuals with AKI admitted to the intensive care unit (ICU), 3,244 (17.0%) received ACEI/ARBs, while 15,830 (83.0%) did not. In the propensity score-matched sample of 6,358 individuals, we found a decreased risk of mortality in those who received ACEI/ARBs compared to those who did not (hazard ratio [HR] for ICU mortality: 0.34, 95% confidence interval [CI]: 0.27–0.42); HR for in-hospital mortality: 0.47, 95% CI: 0.39–0.56; HR for 30-day mortality: 0.47, 95% CI: 0.40–0.56; HR for 180-day mortality: 0.53, 95% CI: 0.45–0.62). However, the use of ACEI/ARBs was associated with a higher risk of AKD (risk ratio [RR]: 1.81; 95% CI: 1.55–2.12). There was no significant association between ACEI/ARBs and an increased risk of hyperkalemia (RR: 1.21; 95% CI: 0.96–1.51).

Conclusions: ACEI/ARB treatment during an episode of AKI may decrease all-cause mortality, but increases the risk of AKD. Future randomized controlled trials are warranted to validate these findings.

Effects of Ramipril on Biomarkers of Endothelial Dysfunction and Inflammation in Hypertensive Children on Maintenance Hemodialysis: the SEARCH Randomized Placebo-Controlled Trial

BACKGROUND

Hypertension, endothelial dysfunction, and inflammation are associated with increased cardiovascular mortality in end-stage kidney disease. We evaluated the effects of ACE (angiotensin-converting enzyme) inhibition on biomarkers of endothelial dysfunction and inflammation in hypertensive children with end-stage kidney disease on maintenance hemodialysis.

METHODS

In a randomized, double-blind, placebo-controlled trial, 135 (72 males/63 females) children and adolescents (age 7-15 years) were randomly assigned to treatment with either 2.5 mg once daily ramipril (n=68) or placebo (n=67) for 16 weeks. Primary outcome were the serum concentrations of asymmetrical dimethylarginine, a marker of endothelial dysfunction and hs-CRP (high-sensitivity C-reactive protein), a marker of inflammation. Changes in IL-6 (interleukin-6), TNF-α (tumor necrosis factor-alpha), systolic (S), and diastolic (D) blood pressure were secondary outcomes. Change in potassium levels and incidence of hyperkalemia were among the safety parameters.

RESULTS

Ramipril, but not placebo, significantly reduced serum levels of asymmetrical dimethylarginine (-79.6%; P<0.001), hs-CRP (-46.5%; P<0.001), IL-6 (-27.1%; P<0.001), and TNF-α (-51.7%; P<0.001). Systolic blood pressure and diastolic blood pressure were significantly lowered in both groups with a greater reduction in children receiving ramipril (median between-group differences -12.0 [95% CI -18.0 to -9.5] and -9.0 [95% CI -12.0 to -4.5]; P<0.001, respectively). Changes in asymmetrical dimethylarginine, hs-CRP, IL-6, or TNF-α in the ramipril group did not significantly correlate with blood pressure reductions. No severe cases of hyperkalemia or other serious treatment-associated adverse events were observed.

CONCLUSIONS

Ramipril improves biomarkers of endothelial dysfunction and inflammation in hypertensive children on maintenance hemodialysis in addition to its efficacious and safe potential to lower blood pressure.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04582097.

Should Renal Inflammation Be Targeted While Treating Hypertension?

Despite extensive research and a plethora of therapeutic options, hypertension continues to be a global burden. Understanding of the pathological roles of known and underexplored cellular and molecular pathways in the development and maintenance of hypertension is critical to advance the field. Immune system overactivation and inflammation in the kidneys are proposed alternative mechanisms of hypertension, and resistant hypertension. Consideration of the pathophysiology of hypertension in chronic inflammatory conditions such as autoimmune diseases, in which patients present with autoimmune-mediated kidney inflammation as well as hypertension, may reveal possible contributors and novel therapeutic targets. In this review, we 1) summarize current therapies used to control blood pressure and their known effects on inflammation; 2) provide evidence on the need to target renal inflammation, specifically, and especially when first-line and combinatory treatment efforts fail; and 3) discuss the efficacy of therapies used to treat autoimmune diseases with a hypertension/renal component. We aim to elucidate the potential of targeting renal inflammation in certain subsets of patients resistant to current therapies.

Insulinotropic Effects of Neprilysin and/or Angiotensin Receptor Inhibition in Mice

Treatment of heart failure with the angiotensin receptor-neprilysin inhibitor sacubitril/valsartan improved glycemic control in individuals with type 2 diabetes. The relative contribution of neprilysin inhibition versus angiotensin II receptor antagonism to this glycemic benefit remains unknown. Thus, we sought to determine the relative effects of the neprilysin inhibitor sacubitril versus the angiotensin II receptor blocker valsartan on beta-cell function and glucose homeostasis in a mouse model of reduced first-phase insulin secretion, and whether any beneficial effects are additive/synergistic when combined in sacubitril/valsartan. High fat-fed C57BL/6J mice treated with low-dose streptozotocin (or vehicle) were followed for eight weeks on high fat diet alone or supplemented with sacubitril, valsartan or sacubitril/valsartan. Body weight and fed glucose levels were assessed weekly. At the end of the treatment period, insulin release in response to intravenous glucose, insulin sensitivity, and beta-cell mass were determined. Sacubitril and valsartan, but not sacubitril/valsartan, lowered fasting and fed glucose levels and increased insulin release in diabetic mice. None of the drugs altered insulin sensitivity or beta-cell mass, but all reduced body weight gain. Effects of the drugs on insulin release were reproduced in angiotensin II-treated islets from lean C57BL/6J mice, suggesting the insulin response to each of the drugs is due to a direct effect on islets and mechanisms therein. In summary, sacubitril and valsartan each exert beneficial insulinotropic, glycemic and weight-reducing effects in obese and/or diabetic mice when administered alone; however, when combined, mechanisms within the islet contribute to their inability to enhance insulin release.

Hemostasis and oxidative stress in chronic kidney disease in children and adolescents

Chronic kidney disease (CKD) can be defined as the progressive loss of renal function, characterized by decreased glomerular filtration rate (GFR). The etiology of CKD in childhood is mainly associated with congenital anomalies of the kidneys and urinary tract (CAKUT) and to glomerular diseases. The goal of this study was to investigate the hemostasis and oxidative stress in pediatric CKD of different etiologies. 54 CKD children and adolescents and 52 controls were enrolled in this study. The evaluation of hemostasis was carried out by determination of D-Dimer (D-Di) and plasminogen activator inhibitor (PAI-1) plasma levels, while oxidative stress by thiobarbituric acid reactive substances (TBARS) levels, protein carbonyl content, plasma antioxidant capacity (MTT) and ascorbate. The D-Di was increased in CAKUT stage 3 or 4 patients compared to those with glomerular disease. PAI-1 was increased in patients with glomerular disease compared to CAKUT. Carbonyl protein content was higher in the control group compared to glomerular disease stage 3 or 4 patients. Our findings showed that the reduction in GFR is associated with a state of hypercoagulability. The analysis of integrated networks showed an expansion of connections among hemostatic and oxidative stress markers in CKD children and adolescents comparing to controls.

Angiotensin II Receptor Blocker Associated With Less Outcome Risk in Patients With Acute Kidney Disease

Objective: The aim of this study was to explore the respective use of angiotensin-converting-enzyme inhibitors (ACEis) or angiotensin receptor blockers (ARBs) on the outcomes of patients who could be weaned from dialysis-requiring acute kidney injury (AKI-D). Methods: This case-control study enrolled 41,731 patients who were weaned from AKI-D for at least 7 days from Taiwan's National Health Insurance Administration. We further grouped AKI-D patients according to ACEi and ARB use to evaluate subsequent risks of all-cause mortality and re-dialysis. The outcomes included the all-cause mortality and new-onset of end-stage kidney disease (ESKD; re-dialysis) following withdraw from AKI-D. Results: A total of 17,141 (41.1%) patients surviving AKI-D could be weaned from dialysis for at least 7 days. The overall events of mortality were 366 (48.9%) in ACEi users, 659 (52.1%) in ARB users, and 6,261 (41.3%) in ACEi/ARB nonusers, during a mean follow-up period of 1.01 years after weaning from AKI-D. In regard to all-cause of mortality, pre-dialysis ARB users had lower incidence than ACEi users [hazard ratio (HR 0.82), p = 0.017]. Compared with ACEi/ARB nonusers, continuing ARB users had a significantly low risk of long-term all-cause mortality (adjusted hazard ratio 0.51, p = 0.013) after propensity score matching. However, new users of ACEi at the acute kidney disease (AKD) period had a higher risk of re-dialysis after weaning than ACEi/ARB nonusers (aHR 1.82, p < 0.001), whereas neither ACEi nor ARB users confronted significantly increased risks of hyperkalemia after weaning. Conclusions: Compared with patients without ACEi/ARB, those continuing to use ARB before the event and after weaning had low all-cause mortality, while new users of ACEi at AKD had increased risk of re-dialysis. AKI-D patients continuing to use ACEi or ARB did not have higher risk of hyperkalemia. Future prospective randomized trials are expected to confirm these findings.

Immunomodulatory Activity of the Most Commonly Used Antihypertensive Drugs-Angiotensin Converting Enzyme Inhibitors and Angiotensin II Receptor Blockers

This review article is focused on antihypertensive drugs, namely angiotensin converting enzyme inhibitors (ACEI) and angiotensin II receptor blockers (ARB), and their immunomodulatory properties reported in hypertensive patients as well as in experimental settings involving studies on animal models and cell lines. The immune regulatory action of ACEI and ARB is mainly connected with the inhibition of proinflammatory cytokine secretion, diminished expression of adhesion molecules, and normalization of CRP concentration in the blood plasma. The topic has significant importance in future medical practice in the therapy of patients with comorbidities with underlying chronic inflammatory responses. Thus, this additional effect of immune regulatory action of ACEI and ARB may also benefit the treatment of patients with metabolic syndrome, allergies, or autoimmune disorders.

Therapeutic potential of pro-resolving mediators in diabetic kidney disease

Renal microvascular disease associated with diabetes [Diabetic kidney disease - DKD] is the leading cause of chronic kidney disease. In DKD, glomerular basement membrane thickening, mesangial expansion, endothelial dysfunction, podocyte cell loss and renal tubule injury contribute to progressive glomerulosclerosis and tubulointerstitial fibrosis. Chronic inflammation is recognized as a major pathogenic mechanism for DKD, with resident and circulating immune cells interacting with local kidney cell populations to provoke an inflammatory response. The onset of inflammation is driven by the release of well described proinflammatory mediators, and this is typically followed by a resolution phase. Inflammation resolution is achieved through the bioactions of endogenous specialized pro-resolving lipid mediators (SPMs). As our understanding of SPMs advances 'resolution pharmacology' based approaches using these molecules are being explored in DKD.

Effect of Kidney Transplantation on Accelerated Immunosenescence and Vascular Changes Induced by Chronic Kidney Disease

Kidney transplantation is the best option for patients with end-stage renal disease. Despite the improvement in cardiovascular burden (leading cause of mortality among patients with chronic kidney disease), cardiovascular adverse outcomes related to the inflammatory process remain a problem. Thus, the aim of the present study was to characterize the immune profile and microvesicles of patients who underwent transplantation. We investigated the lymphocyte phenotype (CD3, CD4, CD8, CD19, and CD56) and monocyte phenotype (CD14, CD16, CD86, and CD54) in peripheral blood, and endothelium-derived microvesicles (annexin V+CD31+CD41–) in plasma of patients with advanced chronic kidney disease (n = 40), patients with transplantation (n = 40), and healthy subjects (n = 18) recruited from the University Hospital “12 de Octubre” (Madrid, Spain). Patients with kidney transplantation had B-cell lymphopenia, an impairment in co-stimulatory (CD86) and adhesion (CD54) molecules in monocytes, and a reduction in endothelium-derived microvesicles in plasma. The correlations between those parameters explained the modifications in the expression of co-stimulatory and adhesion molecules in monocytes caused by changes in lymphocyte populations, as well as the increase in the levels of endothelial-derived microvesicles in plasma caused by changes in lymphocyte and monocytes populations. Immunosuppressive treatment could directly or indirectly induce those changes. Nevertheless, the particular characteristics of these cells may partly explain the persistence of cardiovascular and renal alterations in patients who underwent transplantation, along with the decrease in arteriosclerotic events compared with advanced chronic kidney disease. In conclusion, the expression of adhesion molecules by monocytes and endothelial-derived microvesicles is related to lymphocyte alterations in patients with kidney transplantation.

Confounders in Identification and Analysis of Inflammatory Biomarkers in Cardiovascular Diseases

Proinflammatory biomarkers have been increasingly used in epidemiologic and intervention studies over the past decades to evaluate and identify an association of systemic inflammation with cardiovascular diseases. Although there is a strong correlation between the elevated level of inflammatory biomarkers and the pathology of various cardiovascular diseases, the mechanisms of the underlying cause are unclear. Identification of pro-inflammatory biomarkers such as cytokines, chemokines, acute phase proteins, and other soluble immune factors can help in the early diagnosis of disease. The presence of certain confounding factors such as variations in age, sex, socio-economic status, body mass index, medication and other substance use, and medical illness, as well as inconsistencies in methodological practices such as sample collection, assaying, and data cleaning and transformation, may contribute to variations in results. The purpose of the review is to identify and summarize the effect of demographic factors, epidemiological factors, medication use, and analytical and pre-analytical factors with a panel of inflammatory biomarkers CRP, IL-1b, IL-6, TNFa, and the soluble TNF receptors on the concentration of these inflammatory biomarkers in serum.

Pro-resolving lipid mediators: regulators of inflammation, metabolism and kidney function

Obesity, diabetes mellitus, hypertension and cardiovascular disease are risk factors for chronic kidney disease (CKD) and kidney failure. Chronic, low-grade inflammation is recognized as a major pathogenic mechanism that underlies the association between CKD and obesity, impaired glucose tolerance, insulin resistance and diabetes, through interaction between resident and/or circulating immune cells with parenchymal cells. Thus, considerable interest exists in approaches that target inflammation as a strategy to manage CKD. The initial phase of the inflammatory response to injury or metabolic dysfunction reflects the release of pro-inflammatory mediators including peptides, lipids and cytokines, and the recruitment of leukocytes. In self-limiting inflammation, the evolving inflammatory response is coupled to distinct processes that promote the resolution of inflammation and restore homeostasis. The discovery of endogenously generated lipid mediators - specialized pro-resolving lipid mediators and branched fatty acid esters of hydroxy fatty acids - which promote the resolution of inflammation and attenuate the microvascular and macrovascular complications of obesity and diabetes mellitus highlights novel opportunities for potential therapeutic intervention through the targeting of pro-resolution, rather than anti-inflammatory pathways.

CD40/CD40L Signaling as a Promising Therapeutic Target for the Treatment of Renal Disease

The cluster of differentiation 40 (CD40) is activated by the CD40 ligand (CD40L) in a variety of diverse cells types and regulates important processes associated with kidney disease. The CD40/CD40L signaling cascade has been comprehensively studied for its roles in immune functions, whereas the signaling axis involved in local kidney injury has only drawn attention in recent years. Clinical studies have revealed that circulating levels of soluble CD40L (sCD40L) are associated with renal function in the setting of kidney disease. Levels of the circulating CD40 receptor (sCD40), sCD40L, and local CD40 expression are tightly related to renal injury in different types of kidney disease. Additionally, various kidney cell types have been identified as non-professional antigen-presenting cells (APCs) that express CD40 on the cell membrane, which contributes to the interactions between immune cells and local kidney cells during the development of kidney injury. Although the potential for adverse CD40 signaling in kidney cells has been reported in several studies, a summary of those studies focusing on the role of CD40 signaling in the development of kidney disease is lacking. In this review, we describe the outcomes of recent studies and summarize the potential therapeutic methods for kidney disease which target CD40.

New therapeutic targets in chronic kidney disease progression and renal fibrosis

INTRODUCTION

The current therapeutic armamentarium to prevent chronic kidney disease (CKD) progression is limited to the control of blood pressure and in diabetic patients, the strict control of glucose levels. Current research is primarily focused on the reduction of inflammation and fibrosis at different levels.

AREAS COVERED

This article examines the latest progress in this field and places an emphasis on inflammation, oxidative stress, and fibrosis. New therapeutic targets are described and evidence from experimental and clinical studies is summarized. We performed a search in Medline for articles published over the last 10 years.

EXPERT OPINION

The search for therapeutic targets of renal inflammation is hindered by an incomplete understanding of the pathophysiology. The determination of the specific inducers of inflammation in the kidney is an area of heightened potential. Prevention of the progression of renal fibrosis by blocking TGF-β signaling has been unsuccessful, but the investigation of signaling pathways involved in late stages of fibrosis progression could yield improved results. Preventive strategies such as the modification of microbiota-inducers of uremic toxins involved in CKD progression is a promising field because of the interaction between the gut microbiota and the renal system.

Angiotensin-converting enzyme inhibitor treatment early after myocardial infarction attenuates acute cardiac and neuroinflammation without effect on chronic neuroinflammation

Purpose

Myocardial infarction (MI) triggers a local inflammatory response which orchestrates cardiac repair and contributes to concurrent neuroinflammation. Angiotensin-converting enzyme (ACE) inhibitor therapy not only attenuates cardiac remodeling by interfering with the neurohumoral system, but also influences acute leukocyte mobilization from hematopoietic reservoirs. Here, we seek to dissect the anti-inflammatory and anti-remodeling contributions of ACE inhibitors to the benefit of heart and brain outcomes after MI.

Methods

C57BL/6 mice underwent permanent coronary artery ligation (n = 41) or sham surgery (n = 9). Subgroups received ACE inhibitor enalapril (20 mg/kg, oral) either early (anti-inflammatory strategy; 10 days treatment beginning 3 days prior to surgery; n = 9) or delayed (anti-remodeling; continuous from 7 days post-MI; n = 16), or no therapy (n = 16). Cardiac and neuroinflammation were serially investigated using whole-body macrophage- and microglia-targeted translocator protein (TSPO) PET at 3 days, 7 days, and 8 weeks. In vivo PET signal was validated by autoradiography and histopathology.

Results

Myocardial infarction evoked higher TSPO signal in the infarct region at 3 days and 7 days compared with sham (p < 0.001), with concurrent elevation in brain TSPO signal (+ 18%, p = 0.005). At 8 weeks after MI, remote myocardium TSPO signal was increased, consistent with mitochondrial stress, and corresponding to recurrent neuroinflammation. Early enalapril treatment lowered the acute TSPO signal in the heart and brain by 55% (p < 0.001) and 14% (p = 0.045), respectively. The acute infarct signal predicted late functional outcome (r = 0.418, p = 0.038). Delayed enalapril treatment reduced chronic myocardial TSPO signal, consistent with alleviated mitochondrial stress. Early enalapril therapy tended to lower TSPO signal in the failing myocardium at 8 weeks after MI (p = 0.090) without an effect on chronic neuroinflammation.

Conclusions

Whole-body TSPO PET identifies myocardial macrophage infiltration and neuroinflammation after MI, and altered cardiomyocyte mitochondrial density in chronic heart failure. Improved chronic cardiac outcome by enalapril treatment derives partially from acute anti-inflammatory activity with complementary benefits in later stages. Whereas early ACE inhibitor therapy lowers acute neuroinflammation, chronic alleviation is not achieved by early or delayed ACE inhibitor therapy, suggesting a more complex mechanism underlying recurrent neuroinflammation in ischemic heart failure.

Electronic supplementary material

The online version of this article (10.1007/s00259-020-04736-8) contains supplementary material, which is available to authorized users.

Chronic inflammation in end-stage renal disease and dialysis

Under normal conditions, inflammation is a protective and physiological response to various harmful stimuli. However, in several chronic debilitating disorders, such as chronic kidney disease, inflammation becomes maladaptive, uncontrolled and persistent. Systemic persistent inflammation has, for almost 20 years, been recognized as a major contributor to the uraemic phenotype (such as cardiovascular disease, protein energy wasting, depression, osteoporosis and frailty), and a predictor of cardiovascular and total mortality. Since inflammation is mechanistically related to several ageing processes (inflammageing), it may be a major driver of a progeric phenotype in the uraemic milieu. Inflammation is likely the consequence of a multifactorial aetiology and interacts with a number of factors that emerge when uraemic toxins accumulate. Beside interventions aiming to decrease the production of inflammatory molecules in the uraemic milieu, novel strategies to increase the removal of large middle molecules, such as expanded haemodialysis, may be an opportunity to decrease the inflammatory allostatic load associated with retention of middle molecular weight uraemic toxins.

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.

Potential Protective Role of Blood Pressure-Lowering Drugs on the Balance between Hemostasis and Fibrinolysis in Hypertensive Patients at Rest and During Exercise

In patients with hypertension, the triad represented by endothelial dysfunction, platelet hyperactivity, and altered fibrinolytic function disturbs the equilibrium between hemostasis and fibrinolysis and translates into a hypercoagulable state, which underlies the risk of thrombotic complications. This article reviews the scientific evidence regarding some biological effects of antihypertensive drugs, which can protect patients from the adverse consequences of hypertensive disease, improving endothelial function, enhancing antioxidant activity, and restoring equilibrium between hemostatic and fibrinolytic factors. These protective effects appear not to be mediated through blood pressure reduction and are not shared by all molecules of the same pharmacological class.

Novel PAradigm to improve Inflammatory burden in end stage Renal disease (rePAIR): study protocol for a randomized controlled trial

Background

Given the importance of inflammation as a predictor of poor outcomes in End Stage Renal Disease (ESRD), reductions in inflammatory biomarkers have been proposed as a critical target in this population. This study targets chronic periodontitis, an oral inflammatory disease of microbial etiology causing persistent inflammation in ESRD. Unlike the previously reported episodic periodontal interventions, we propose to control periodontal inflammation with a continuous maintenance and oral health behavior modifications. We hypothesize that this strategy will improve systemic inflammation and oxidative stress, oral health and quality of life within the 6-month observation period.

Methods

The rePAIR (novel PAradigm to improve Inflammatory burden in ESRD) study is a pilot and feasibility, parallel-arm, and randomized controlled clinical trial that will recruit 72 ESRD subjects with periodontitis in a model of computerized block randomization. This trial aims to compare the effect of standard-of-care vs. repeated non-surgical periodontal therapy on systemic and oral inflammatory burden. This trial will recruit ESRD adult patients with periodontitis older than 21 years old with a minimum of 12 teeth and no history of periodontal treatment within a year. The trial will examine serum C-reactive protein (CRP) (primary outcome) as a biomarker of inflammation as well as interleukin-6 (IL-6), F2 isofurans and F2 isoprostanes (secondary outcomes) and compare their difference between groups from baseline to 6 months. The trial will also compare the difference between groups in patient-centered and clinical oral outcomes from baseline to 6 months.

Discussion

The trial follows a rigorous and transparent study design capturing elements such as pre-specified eligibility criteria, pre-specified primary and secondary outcomes, detailed intervention description to allow replication, intervention random allocation and concealment, blinding in outcome assessment, appropriate sample size calculations, explanation of interim analysis, as per CONSORT Guidelines. Further, gender diversity is secured not only at recruitment but also throughout the trial and during the analysis. Therefore, treatment response outcomes will be examined per gender category. In order to manage anticipated problems, the protocol has included alternative approaches.

Trial registration

ClinicalTrials.gov, NCT03241511. Registered on 7 August 2017.

Electronic supplementary material

The online version of this article (10.1186/s13063-018-2760-y) contains supplementary material, which is available to authorized users.

Strategies to decrease oxidative stress biomarker levels in human medical conditions: A meta-analysis on 8-iso-prostaglandin F2α

The widespread detection of elevated oxidative stress levels in many medical conditions has led to numerous efforts to design interventions to reduce its effects. Efforts have been wide-ranging, from dietary changes to administration of antioxidants, supplements, e.g., omega-3-fatty acids, and many medications. However, there is still no systemic assessment of the efficacy of treatments for oxidative stress reduction across a variety of medical conditions. The goal of this meta-analysis is, by combining multiple studies, to quantitate the change in the levels of the popular oxidative stress biomarker 8-iso-prostaglandin F2α (8-iso-PGF2α) after a variety of treatment strategies in human populations. Nearly 350 unique publications with 180 distinct strategies were included in the analysis. For each strategy, the difference between pre- or placebo and post-treatment levels calculated using Hedges' g value of effect. In general, administration of antibiotics, antihyperlipidemic agents, or changes in lifestyle (g = - 0.63, - 0.54, and 0.56) had the largest effect. Administration of supplements, antioxidants, or changes in diet (g = - 0.09, - 0.28, - 0.12) had small quantitative effects. To fully interpret the effectiveness of these treatments, comparisons to the increase in g value for each medical condition is required. For example, antioxidants in populations with coronary artery disease (CAD) reduce the 8-iso-PGF2α levels by g = - 0.34 ± 0.1, which is quantitatively considered a small effect. However, CAD populations, in comparison to healthy populations, have an increase in 8-iso-PGF2α levels by g = 0.38 ± 0.04; therefore, the overall reduction of 8-iso-PGF2α levels is ≈ 90% by this treatment in this specific medical condition. In conclusion, 8-iso-PGF2α levels can be reduced not only by antioxidants but by many other strategies. Not all strategies are equally effective at reducing 8-iso-PGF2α levels. In addition, the effectiveness of any strategy can be assessed only in relation to the medical condition investigated.

The binding of captopril to angiotensin I-converting enzyme triggers activation of signaling pathways

Hypertension is a global health problem, and angiotensin I (ANG I)-converting enzyme (ACE) inhibitors are largely used to control this pathology. Recently, it has been shown that ACE can also act as a transducer signal molecule when its inhibitors or substrates bind to it. This new role of ACE could contribute to understanding some of the effects not explained by its catalytic activity only. In this study, we investigated signaling pathway activation in Chinese hamster ovary (CHO) cells stably expressing ACE (CHO-ACE) under different conditions. We also investigated gene modulation after 4 h and 24 h of captopril treatment. Our results demonstrated that CHO-ACE cells when stimulated with ANG I, ramipril, or captopril led to JNK and ERK1/2 phosphorylation. To verify any physiological role at the endogenous level, we made use of primary cultures of mesangial cells from spontaneously hypertensive rats (SHR) and Wistar rats. Our results showed that ERK1/2 activation occurred mainly in primary cultures of mesangial cells from SHR rats upon captopril stimulation, suggesting that this signaling pathway could be differentially regulated during hypertension. Our results also showed that captopril treatment leads to a decrease of cyclooxygenase 2, interleukin-1β, and β-arrestin2 and a significant increase of AP2 gene expression levels. Our findings strengthen the fact that, in addition to the blockage of enzymatic activity, ACE inhibitors also trigger signaling pathway activation, and this may contribute to their beneficial effects in the treatment of hypertension and other pathologies.

Angiotensin receptor blocker vs ACE inhibitor effects on HDL functionality in patients on maintenance hemodialysis

BACKGROUND AND AIMS

Angiotensin receptor blockers (ARB) and angiotensin converting enzyme inhibitors (ACEI) reduce cardiovascular events in the general population. Maintenance hemodialysis (MHD) patients are at high cardiovascular risk but few studies have directly addressed the comparative efficacy of these drugs. MHD disrupts the normally atheroprotective actions of high density lipoprotein (HDL), therefore, we compared ACEI or ARB treatment on HDL functions in MHD.

METHODS AND RESULTS

HDL was isolated at the starting point (pre) and 3-6 months later (post) in 30 MHD randomly assigned to placebo, ramipril or valsartan. Outcomes included cholesterol efflux, inflammatory cytokine response, effects on Toll-like receptors (TLR), superoxide production, methylarginine and serum amyloid A (SAA) levels. HDL from ARB- or ACEI-treated subjects was more effective in maintaining efflux than HDL of placebo. HDL from ARB- or ACEI-treated subjects but not placebo lessened cellular superoxide production. In contrast, neither ARB nor ACEI improved HDL anti-inflammatory effect. Indeed, HDL of ACEI-treated subjects potentiated the cytokine responses in association with activation of TLR but did not alter the HDL content of methylarginines or SAA.

CONCLUSION

Both ACEI and ARB stabilized HDL cholesterol acceptor function and sustained cellular anti-oxidative effects but not anti-inflammatory effects, and ACEI-treatment instead amplified the HDL inflammatory response. The findings reveal possible utility of antagonizing angiotensin actions in MDH and suggest a possible mechanism for superiority of ARB vs ACEI in the setting of advanced kidney disease.

Primary prevention of myocardial infarction with angiotensin-converting enzyme inhibitors and angiotensin receptor blockers in hypertensive patients with rheumatoid arthritis-A nationwide cohort study

Background

Rheumatoid arthritis (RA) is regarded as a high risk factor for myocardial infarction. Hypertension is a major modifiable risk factor contributing to increased risk of myocardial infarction (MI). Dual blood pressure (BP)-lowering and anti-inflammatory effect of renin-angiotensin-system (RAS) inhibitors may possess protective effect from MI in RA population. However, treatment of hypertension with RAS inhibitors and MI in RA population remains unclear.

Methods

We investigated whether RAS blockade could decrease risk of incident MI in hypertensive patients with RA. We identified patients with RA and hypertension from the Registry for Catastrophic Illness, a nation-wide database encompassing almost all of the RA patients in Taiwan from 1995 to 2008. The primary endpoint was MI and the median duration of follow up was 2,986 days. Propensity score weighting and Cox proportional hazards regression models were used to estimate hazard ratios for MI.

Results

Among 27,335 subjects, 9.9% received angiotensin-converting enzyme inhibitors (ACEIs), 25.9% received angiotensin II receptor blockers (ARBs) and 20.0% received ACEIs or ARBs alternatively. The incidence of MI significantly decreased in patients treated with ACEIs (hazard ratio 0.707; 95% confidence interval 0.595–0.840), ARBs (0.641; 0.550–0.747) and ACEIs/ARBs (0.631; 0.539–0.739). The protective effect of ACEI or ARB therapy was significantly better in patients taking longer duration. The effect remained robust in subgroup analyses.

Conclusions

Therapy of ACEIs or ARBs is associated with a lower risk of MI among patients with RA. Hence, hypertension in patients with RA could comprise a compelling indication for RAS inhibitors.

Angiotensin receptor blockers are associated with lower mortality than ACE inhibitors in predialytic stage 5 chronic kidney disease: A nationwide study of therapy with renin-angiotensin system blockade

Dual renin angiotensin system (RAS) blockade using angiotensin-receptor blockers (ARBs) in combination with angiotensin converting enzyme inhibitors (ACEIs) is reported to improve proteinuria in both diabetic and non-diabetic patients. However, its renoprotective effect and safety remain uncertain in patients with advanced chronic kidney disease (CKD). From January 1, 2000 through June 30, 2009, we enrolled 14,117 pre-dialytic stage 5 CKD patients with serum creatinine >6mg/dL and hematocrit <28% under the treatment with erythropoiesis stimulating agents and RAS blockade. We used Cox proportional hazards regression models to estimate the hazard ratios (HRs) against the commencement of long-term dialysis and all-cause mortality for ACEI/ARB users. Over a median follow-up of 7 months, 9,867 patients (69.9%) required long-term dialysis and 2,805 (19.9%) died before progression to end-stage renal disease requiring dialysis. In comparison with the ARB-only users, dual blockade with ACEIs and ARBs was associated with a significantly higher risk of (1) death in all CKD patients (HR = 1.49, [95%CI, 1.30-1.71]; P = 0.02) and in diabetic subgroup (HR = 1.58, [95%CI, 1.34-1.86]; P = 0.02); (2) composite endpoint of long-term dialysis or death in diabetic subgroup (HR = 1.10, [95%CI, 1.01-1.20]; P = 0.04); (3) hyperkalemia-associated hospitalization in non-diabetic subgroup (HR, 2.74, [95%CI, 1.05-7.15]; P = 0.04). However, ACEIs users were associated with higher mortality than ARBs users in all CKD patients (HR = 1.17, [95%CI, 1.07-1.27]; P = 0.03) and in diabetic subgroup (HR = 1.32, [95%CI, 1.18-1.48]; P = 0.03). Monotherapy of RAS blockade, especially ARB, is more effective and safer than dual RAS blockade in pre-dialytic stage 5 CKD patients.

New insights into the non-hemostatic role of von Willebrand factor in endothelial protection

During exposure to ischemia-reperfusion (I/R) insult, angiotensin II (AngII)-induced endothelin-1 (ET-1) upregulation in endothelial cells progressively impairs nitric oxide (NO) bioavailability while increasing levels of superoxide anion (O₂^-) and leading to the onset of endothelial dysfunction. Moreover, the overexpression of ET-1 increases the endothelial and circulating levels of von Willebrand factor (vWF), a glycoprotein with a crucial role in arterial thrombus formation. Nowadays, the non-hemostatic role of endothelial vWF is emerging, although we do not yet know whether its increased expression is cause or consequence of endothelial dysfunction. Notably, the vWF blockade or depletion leads to endothelial protection in cultured cells, animal models of vascular injury, and patients as well. Despite the recent efforts to develop an effective pharmacological strategy, the onset of endothelial dysfunction is still difficult to prevent and remains closely related to adverse clinical outcome. Unraveling the non-hemostatic role of endothelial vWF in the onset of endothelial dysfunction could provide new avenues for protection against vascular injury mediated by AngII.

Protocol of randomized control trial for effectiveness of angiotensin receptor blockers on blood pressure control among euvolemic hypertensive hemodialysis patients

INTRODUCTION

Volume overload and the renin-aldosterone-angiotensin system (RAAS) are 2 major factors contributing to hypertension (HTN) among hemodialysis (HD) patients. Although volume-dependent components of HTN can be corrected by appropriate volume removal, a proportion of HD patients experience elevated blood pressure (BP) despite achieving euvolemic and ideal dry weight.

METHOD AND ANALYSIS

A single center, prospective, randomized, parallel design, single-blind trial will be conducted in the Malaysian state of Kelantan among postdialysis euvolemic hypertensive patients that are on regular dialysis at least 3 times a week. The primary outcome of the trial will be to note the effectiveness of losartan (RAAS inhibitor) in reducing systolic BP < 140 mm Hg compared to standard non-RAAS-inhibitor antihypertensive therapy. The secondary outcome will be to look at all causes of mortality. A body composition monitor (BCM) will be used to assess postdialysis volume and dry weight. Postdialysis euvolemic patients that have systolic BP > 140 mm Hg will be randomized using Covariate Adaptive Randomization to standard or treatment arm. Participants in the treatment arm will be given 50 mg of losartan once daily except on dialysis days, whereas the standard arm patients will be prescribed non-RAAS antihypertensive agents. The study participants will be followed for a period of 12 months. A Wilcoxon statistical test will be performed to note the difference in BP from baseline up to 12 months using Statistical Package for the Social Sciences (SPSS) 20.

ETHICAL AND TRIAL REGISTRATION

The study protocols are approved from the Ethical and Research Committee of the Universiti Sains Malaysia (USM/JEPeM/15050173). The trial is registered under the Australia New Zealand Clinical Trial Registry (ACTRN12615001322527). The trial was registered on 2/12/2015 and the 1st patient was enrolled on 10/12/2015. The trial was formally initiated on 16/02/2016.

CONCLUSION

Management of HTN among HD patients requires understanding the primary cause of HTN and treating accordingly. The current trial is an attempt to reduce BP among postdialysis euvolemic but hypertensive patients.

Immunologic Effects of the Renin-Angiotensin System

Inappropriate activation of the renin-angiotensin system (RAS) exacerbates renal and vascular injury. Accordingly, treatment with global RAS antagonists attenuates cardiovascular risk and slows the progression of proteinuric kidney disease. By reducing BP, RAS inhibitors limit secondary immune activation responding to hemodynamic injury in the target organ. However, RAS activation in hematopoietic cells has immunologic effects that diverge from those of RAS stimulation in the kidney and vasculature. In preclinical studies, activating type 1 angiotensin (AT₁) receptors in T lymphocytes and myeloid cells blunts the polarization of these cells toward proinflammatory phenotypes, protecting the kidney from hypertensive injury and fibrosis. These endogenous functions of immune AT₁ receptors temper the pathogenic actions of renal and vascular AT₁ receptors during hypertension. By counteracting the effects of AT₁ receptor stimulation in the target organ, exogenous administration of AT₂ receptor agonists or angiotensin 1-7 analogs may similarly limit inflammatory injury to the heart and kidney. Moreover, although angiotensin II is the classic effector molecule of the RAS, several RAS enzymes affect immune homeostasis independently of canonic angiotensin II generation. Thus, as reviewed here, multiple components of the RAS signaling cascade influence inflammatory cell phenotype and function with unpredictable and context-specific effects on innate and adaptive immunity.

Comparative Effectiveness of Renin-Angiotensin System Antagonists in Maintenance Dialysis Patients

BACKGROUND/AIMS

Whether angiotensin converting enzyme inhibitors (ACE) and angiotensin receptor blockers (ARB) are differentially associated with reductions in cardiovascular events and mortality in patients receiving maintenance dialysis is uncertain. We compared outcomes between ACE and ARB users among hypertensive, maintenance dialysis patients.

METHODS

National retrospective cohort study of hypertensive, Medicare-Medicaid eligible patients initiating chronic dialysis between 1/1/2000 to 12/31/2005. The exposure of interest was new use of either an ACEI or ARB. Outcomes were all-cause mortality (ACM) and combined cardiovascular hospitalization or death (CV-endpoint). Cox proportion hazards models were used to compare the effect of ACEI vs ARB use on ACM and, separately, CV-endpoint.

RESULTS

ACM models were based on 3,555 ACEI and 1,442 ARB new users, while CV-endpoint models included 3,289 ACEI and 1,346 ARB new users. After statistical adjustments, ACEI users had higher hazard ratios for ACM (AHR = 1.22, 99% CI 1.05-1.42) and CV-endpoint (AHR = 1.12, 99% CI 0.99-1.27).

CONCLUSIONS

Patients initiating maintenance dialysis who received an ACEI faced an increased risk for mortality and a trend towards an increased risk for CV-endpoints when compared to patients who received an ARB. Validation of these results in a rigorous clinical trial is warranted.

Gene silencing of endothelial von Willebrand Factor attenuates angiotensin II-induced endothelin-1 expression in porcine aortic endothelial cells

Expression of endothelin (ET)-1 is increased in endothelial cells exposed to angiotensin II (Ang II), leading to endothelial dysfunction and cardiovascular disorders. Since von Willebrand Factor (vWF) blockade improves endothelial function in coronary patients, we hypothesized that targeting endothelial vWF with short interference RNA (siRNA) prevents Ang II-induced ET-1 upregulation. Nearly 65 ± 2% silencing of vWF in porcine aortic endothelial cells (PAOECs) was achieved with vWF-specific siRNA without affecting cell viability and growth. While showing ET-1 similar to wild type cells at rest, vWF-silenced cells did not present ET-1 upregulation during exposure to Ang II (100 nM/24 h), preserving levels of endothelial nitric oxide synthase activity similar to wild type. vWF silencing prevented AngII-induced increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity and superoxide anion (O2-) levels, known triggers of ET-1 expression. Moreover, no increase in O2- or ET-1 levels was found in silenced cells treated with AngII or NOX-agonist phorbol ester (PMA 5 nM/48 h). Finally, vWF was required for overexpression of NOX4 and NOX2 in response to AngII and PMA. In conclusion, endothelial vWF knockdown prevented Ang II-induced ET-1 upregulation through attenuation of NOX-mediated O2- production. Our findings reveal a new role of vWF in preventing of Ang II-induced endothelial dysfunction.

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.

Association between Von Willebrand factor, disintegrin and metalloproteinase with thrombospondin type 1 motif member 13, d-Dimer and cystatin C levels with retinopathy in type 1 diabetes mellitus

BACKGROUND

We evaluated the association between plasma levels of VWF, ADAMTS13 and d-Dimer, which consist on endothelial dysfunction and hypercoagulability biomarkers, and cystatin C with retinopathy in type 1 diabetic patients.

METHODS

Patients were classified according to presence (n=55) or absence (n=70) of retinopathy. Plasma levels of VWF, ADAMTS13, d-Dimer and cystatin C were evaluated by ELISA and ADAMTS13 activity was evaluated by FRET.

RESULTS

Plasma levels of VWF (p=0.033), ADAMTS13 activity (p=0.014), d-Dimer (p=0.002) and cystatin C (p<0.001) were elevated in diabetic patients with retinopathy compared to those without this complication. The multivariate logistic regression analysis showed that ADAMTS13 activity (p=0.031) d-Dimer (p=0.015) and cystatin C (p=0.001) remained associated with retinopathy after adjustment for age, diabetes duration, use of statin, use of ACEi or angiotensin antagonist, use of acetylsalicylic acid and glomerular filtration rate.

CONCLUSION

ADAMTS13 activity, d-Dimer and cystatin C are associated with retinopathy in type 1 diabetic patients and are promising biomarkers for the diagnosis and monitoring of diabetic retinopathy.

Therapeutics targeting persistent inflammation in chronic kidney disease

Systemic inflammation is a condition intrinsically linked to chronic kidney disease (CKD) and its other typical sequelae, such as acquired immune dysfunction, protein-energy wasting (PEW), and accelerated vascular aging that promote premature cardiovascular disease (CVD) and infections, the two leading causes of death in CKD patients. Inflammation is a major contributor to complications in CKD, and inflammatory markers, such as C-reactive protein and pro- and anti-inflammatory cytokines, correlate with underlying causes and consequences of the inflamed uremic phenotype, such as oxidative stress, endothelial dysfunction, CVD, PEW, and infections, and are sensitive and independent predictors of outcome in CKD. Therefore, inflammation appears to be a logical target for potential preventive and therapeutic interventions in patients with CKD. Putative anti-inflammatory therapy strategies aiming at preventing complications and improving outcomes in CKD span over several areas: (1) dealing with the source of inflammation (such as cardiovascular, gastrointestinal or periodontal disease and depression); (2) providing nonspecific immune modulatory effects by promoting healthy dietary habits and other lifestyle changes; (3) promoting increased use of recognized pharmacologic interventions that have pleiotropic effects; and, (4) introducing novel targeted anticytokine interventions. This review provides a brief update on inflammatory biomarkers and possible therapeutic approaches targeting inflammation and the uremic inflammatory milieu in patients with CKD.

Add-on Protective Effect of Pentoxifylline in Advanced Chronic Kidney Disease Treated with Renin-Angiotensin-Aldosterone System Blockade - A Nationwide Database Analysis

A combination therapy of pentoxifylline with an angiotensin converting enzyme inhibitor (ACEI) or an angiotensin II receptor blocker (ARB) decreased proteinuria or glomerular filtration rate decline in early chronic kidney disease (CKD). Whether adding pentoxifylline to ACEI/ARB provides additional benefits on outcome is unclear in CKD stage 5 patients who have not yet received dialysis (CKD 5 ND). A prospective cohort study was conducted based on the Taiwan National Health Insurance Research Database. From January 1, 2000 to June 30, 2009, we enrolled 14,117 CKD 5 ND with serum creatinine levels >6 mg/dL and hematocrit levels <28% and who have been treated with ACEI/ARB. All patients were divided into pentoxifylline users and nonusers. Patient follow-up took place until dialysis, death before initiation of dialysis or December 31, 2009. Finally, 9,867 patients (69.9%) required long-term dialysis and 2,805 (19.9%) died before dialysis. After propensity score-matching, use of pentoxifylline was associated with a lower risk for long-term dialysis or death in ACEI/ARB users (HR, 0.94; 95% CI, 0.90–0.99) or ARB users (HR, 0.91; 95% CI, 0.85–0.97). In conclusion, pentoxifylline exhibited a protective effect in reducing the risk for the composite outcome of long-term dialysis or death in ACEI/ARB treated CKD 5 ND.

Angiotensin converting enzyme inhibition increases ADMA concentration in patients on maintenance hemodialysis--a randomized cross-over study

Background

Endothelial dysfunction occurs in patients with end-stage renal disease (ESRD) and is associated with increased cardiovascular morbidity and mortality. Asymmetric dimethylarginine (ADMA) contributes to endothelial dysfunction in ESRD. In the general population, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) decrease ADMA levels, but no study has compared the effect of these drugs in patients with ESRD on maintenance hemodialysis (MHD).

Methods

We evaluated the effect of 1-week treatment with ramipril (5 mg/d), valsartan (160 mg/d), and placebo on ADMA levels in 15 patients on MHD in a double-blind, placebo-controlled, three x three cross-over study.

Results

We found that ADMA levels were increased at baseline and throughout the dialysis session during ramipril treatment (p < 0.001 compared to both, placebo and valsartan). Ramipril did not increase ADMA levels in a study of patients without ESRD, suggesting that factors related to ESRD or hemodialysis contribute to the ACE inhibitor-induced increase in ADMA. We have previously shown that ACE inhibition increases bradykinin (BK) levels during hemodialysis. We therefore evaluated the effect of bradykinin on ADMA production in A549 cells; a cell line that expresses BK receptors. Incubation with BK increased intracellular ADMA concentration through BK B2-receptor stimulation.

Conclusion

These data indicate that short-term ACE inhibition increases ADMA in patients on MHD whereas ARBs do not. In vitro studies further suggest that this may occur through BK-mediated increase in ADMA production during ACE inhibition.

Trial registration

Clinicaltrials.gov NCT00732069 August 6 2008 and NCT00607672 February 4 2008

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0162-x) contains supplementary material, which is available to authorized users.

C-reactive Protein: Repeated Measurements will Improve Dialysis Patient Care

Systemic inflammation is a common feature in the uremic phenotype and associates with poor outcomes. The awareness regarding the importance of inflammation assessment in chronic kidney disease (CKD) patients has risen in recent years, and despite the development of novel biomarkers, C-reactive protein (CRP) is still the most measured inflammatory parameter. Notwithstanding, the possible weak points of CRP determination, this biomarker has demonstrated being useful both for guidance in clinical practice and for risk estimation. In addition, regular determination of CRP among dialysis patients has been associated with better outcomes in different dialysis facilities. Because persistent inflammation may be a silent reflection of various pathophysiologic alterations in CKD, it is crucial that inflammatory markers are regularly monitored and therapeutic attempts be made to target this inflammation.

Correlation of Inflammation and Lipoprotein (a) with Hypercoagulability in Hemodialysis Patients

Background:

Inflammatory and procoagulant markers are potential mediators for the cardiovascular risk in hemodialysis patients. Lipoprotein (a) [Lp(a)], is another important risk factor with inflammatory and procoagulant effects.

Materials and methods:

In 78 hemodialysis patients and 40 controls, C-reactive protein (CRP), Interleukin-6 (IL-6), lipoprotein (a) [Lp (a)], fibrinogen, D-dimer, von Wilebrand factor (vWF) and serum albumin were determined.

Results:

CRP, IL-6, Lp(a), fibrinogen, D-dimer and vWF, were significantly higher, and serum albumin was significantly lower in patients compared to controls (24.40 mg/L vs. 6.39 mg/L, p<0.001; 1.92 pg/ml vs. 0.35 pg/ml, 28.05 mg/dL vs.16.25 mg/dL, p<0.001; 3.44 g/L vs. 2.55 g/L, p<0.01; 1.81 µgFEU /ml vs. 0.50 µgFEU /ml, p<0.01; 152.9 % vs. 85.6 %, p<0.001; 32.1 g/L vs. 40.50 g/L, p<0.001). The patients were divided into two groups: 40 patients with CRP levels over than 10 mg/L and 38 with CRP levels in normal range. These parameters showed significant differences between patients with elevated CRP and patients with normal CRP levels. CRP and IL-6 correlated positively with Lp(a), (r = 0.62, p < 0.001; r=0.54, p<0.001), fibrinogen, (r = 0.63, p < 0.001; r = 0.49, p<0.01) D dimer (r = 0.72, p<0.001; r = 0.55, p<0.01), vWF (r = 0.76, p<0.01; r = 0.63, p<0.001) and negatively with serum albumin (r = -0.80, p<0.01; r = -0.60, p<0.001), in patients with elevated CRP, but not in patients with normal CRP levels and controls.

Conclusion:

According to the results hemodialysis patients with increased inflammatory markers, have the elevated Lp(a) and procoagulant markers and the greater risk for atherosclerotic cardiovascular disease.

Preserving residual renal function in dialysis: what we know

Residual renal function confers a survival benefit among dialysis patients thought to be related to greater volume removal and solute clearance. Whether the presence of residual renal function is protective or merely a marker for better health is not clear. The basic mechanisms governing the decline or persistence of residual renal function are poorly understood and few studies have examined the role of medical therapy in its preservation. Dialysis modality, inflammatory processes often associated with comorbid diseases (including diabetes mellitus and obesity), volume dysregulation, and vitamin D deficiency are predictive of residual renal function decline. We review potential mechanisms for preservation of remaining glomerular filtration rate among chronic dialysis patients.

Paricalcitol reduces oxidative stress and inflammation in hemodialysis patients

BACKGROUND

Treatment with selective vitamin D receptor activators such as paricalcitol have been shown to exert an anti-inflammatory effect in patients on hemodialysis, in addition to their action on mineral metabolism and independently of parathyroid hormone (PTH) levels. The objective of this study was to evaluate the additional antioxidant capacity of paricalcitol in a clinical setting.

METHODS

The study included 19 patients with renal disease on hemodialysis, of whom peripheral blood was obtained for analysis at baseline and three months after starting intravenous paricalcitol treatment. The following oxidizing and inflammatory markers were quantified: malondialdehyde (MDA), nitrites and carbonyl groups, indoleamine 2,3-dioxygenase (IDO), tumor necrosis factor alfa (TNF-α), interleukin-6 (IL-6), interleukin-18 (IL-18) and C-reactive protein (CRP). Of the antioxidants and anti-inflammatory markers, superoxide dismutase (SOD), catalase, reduced glutathione (GSH), thioredoxin, and interleukin-10 (IL-10) levels were obtained.

RESULTS

Baseline levels of oxidation markers MDA, nitric oxide and protein carbonyl groups significantly decreased after three months on paricalcitol treatment, while levels of GSH, thioredoxin, catalase and SOD activity significantly increased. After paricalcitol treatment, levels of the inflammatory markers CRP, TNF-α, IL-6 and IL-18 were significantly reduced in serum and the level of anti-inflammatory cytokine IL-10 was increased.

CONCLUSIONS

In renal patients undergoing hemodialysis, paricalcitol treatment significantly reduces oxidative stress and inflammation, two well known factors leading to cardiovascular damage.