Angiotensin converting enzyme inhibitors suppress production of tumor necrosis factor-alpha in vitro and in vivo

Correlation between serum angiotensin-converting enzyme (ACE) levels and intervertebral disc degeneration

Studies have shown that the renin-angiotensin system (RAS) might play an essential role in intervertebral disc degeneration (IDD). The study aimed to investigate the relationship between serum angiotensin-converting enzyme (ACE) concentration and IDD and its predictive value for severe disc degeneration. 245 patients who came to our hospital for low back pain were recruited, and blood samples were collected for routine examination. Descriptive data and demographic parameters were collected. The cumulative grade 1 was calculated by summing up the Pfirrmann grade of all lumbar discs. ACE concentration grouping was determined via tertile split. Correlation analysis and multivariable linear regression analysis were performed to determine the relationship between ACE and IDD. The receiver's degree of disc degeneration (ROC) curve determined the ACE's predictive value. Results indicated that there was no significant difference in demographic parameters among groups. Correlation analysis and multivariate linear analysis showed that ACE was an independent risk factor for IDD. The cumulative grade 1 increased significantly with the increase in ACE concentration, which was consistent with the correlation analysis. Average Pfirrmann grade < 4 indicates mild to moderate degeneration, and grade ≥ 4 indicates severe degeneration in terms of an individual disc. From L1/2 to L5/S1, the mean plasma ACE concentration was significantly higher in the severe degeneration group than in the mild to moderate degeneration group. According to the ROC curve, the cut-off value of ACE levels was 22.5. patients with ACE > 22.5 had severe degeneration. The sensitivity and specificity were 0.762 and 0.521, respectively.

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.

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.

Anti-Inflammatory Activities of Captopril and Diuretics on Macrophage Activity in Mouse Humoral Immune Response

Hypertension is accompanied by the over-activation of macrophages. Diuretics administered alone or in combination with hypotensive drugs may have immunomodulatory effects. Thus, the influence of tested drugs on mouse macrophage-mediated humoral immunity was investigated. Mice were treated intraperitoneally with captopril (5 mg/kg) with or without hydrochlorothiazide (10 mg/kg) or furosemide (5 mg/kg) by 8 days. Mineral oil-induced peritoneal macrophages were harvested to assess the generation of cytokines in ELISA, and the expression of surface markers was analyzed cytometrically. Macrophages were also pulsed with sheep red blood cells (SRBC) and transferred to naive mice for evaluation of their ability to induce a humoral immune response. Tested drugs increase the expression of surface markers important for the antigen phagocytosis and presentation. SRBC-pulsed macrophages from mice treated with captopril combined with diuretics increased the secretion of antigen-specific antibodies by recipient B cells, while macrophages of mice treated with hydrochlorothiazide or furosemide with captopril increased the number of antigen-specific B cells. Tested drugs alter the macrophage secretory profile in favor of anti-inflammatory cytokines. Our results showed that diuretics with or without captopril modulate the humoral response by affecting the function of macrophages, which has significant translational potential in assessing the safety of antihypertensive therapy.

Renin-angiotensin system in intestinal inflammation-Angiotensin inhibitors to treat inflammatory bowel diseases?

Inflammatory bowel diseases (IBDs) are chronic disorders of the gastrointestinal tract, which manifest in recurring gastrointestinal inflammation. The current treatment options of IBD are not curative and are lacking in aspects like prevention of fibrosis. New treatment options are needed to fulfil the unmet needs and provide alternatives to drugs with resistances and side effects. Drugs targeting the renin-angiotensin system (RAS), besides being antihypertensive, also possess anti-inflammatory and antifibrotic properties and could offer an inexpensive alternative to control inflammation and fibrosis in the gut. RAS inhibitors have been effective in preventing and alleviating colitis in preclinical studies, but available human data are still sparse. This review outlines the pathophysiological functions of RAS in the gut and summarizes preclinical studies utilizing pharmacological RAS inhibitors in the treatment of experimental colitis. We discuss the alterations in intestinal RAS and the available evidence of the benefits of RAS inhibitors for IBD patients. Retrospective studies comparing IBD patients using ACE inhibitors or angiotensin II receptor blockers have provided optimistic results regarding a milder disease course and fewer hospitalizations and corticosteroid use in patients using RAS inhibitors. Prospective studies are needed to evaluate the effectiveness of these promising medications in the treatment of IBD.

The potential similarities of COVID-19 and autoimmune disease pathogenesis and therapeutic options: new insights approach

Abstract

Cytokine pathways and their signaling disorders can be the cause of onset and pathogenesis of many diseases such as autoimmune diseases and COVID-19 infection. Autoimmune patients may be at higher risk of developing infection due to the impaired immune responses, the use of immunosuppressive drugs, and damage to various organs. Increased secretion of inflammatory cytokines and intolerance of the patient’s immune system to COVID-19 infection are the leading causes of hospitalization of these patients. The content used in this paper has been taken from English language articles (2005–2020) retrieved from the PubMed database and Google Scholar search engine using “COVID-19,” “Autoimmune disease,” “Therapeutic,” “Pathogenesis,” and “Pathway” keywords. The emergence of COVID-19 and its association with autoimmune disorders is a major challenge in the management of these diseases. The results showed that the use of corticosteroids in the treatment of autoimmune diseases can make diagnosis and treatment of COVID-19 more challenging by preventing the fever. Due to the common pathogenesis of COVID-19 and autoimmune diseases, the use of autoimmune drugs as a possible treatment option could help control the virus.

Key Points

• Inflammatory cytokines play an essential role in the pathogenesis of COVID-19

• ACE2 dysfunctions are related to the with COVID-19 and autoimmune diseases

• The use autoimmune diseases drugs can be useful in treating COVID-19

ACE2 as a Therapeutic Target for COVID-19; its Role in Infectious Processes and Regulation by Modulators of the RAAS System

Angiotensin converting enzyme 2 (ACE2) is the recognized host cell receptor responsiblefor mediating infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). ACE2bound to tissue facilitates infectivity of SARS-CoV-2; thus, one could argue that decreasing ACE2tissue expression would be beneficial. However, ACE2 catalytic activity towards angiotensin I (AngI) and II (Ang II) mitigates deleterious effects associated with activation of the renin-angiotensinaldosteronesystem (RAAS) on several organs, including a pro-inflammatory status. At the tissuelevel, SARS-CoV-2 (a) binds to ACE2, leading to its internalization, and (b) favors ACE2 cleavage toform soluble ACE2: these actions result in decreased ACE2 tissue levels. Preserving tissue ACE2activity while preventing ACE2 shredding is expected to circumvent unrestrained inflammatoryresponse. Concerns have been raised around RAAS modulators and their effects on ACE2expression or catalytic activity. Various cellular and animal models report conflicting results invarious tissues. However, recent data from observational and meta-analysis studies in SARS-CoV-2-infected patients have concluded that RAAS modulators do not increase plasma ACE2 levels orsusceptibility to infection and are not associated with more severe diseases. This review presentsour current but evolving knowledge of the complex interplay between SARS-CoV-2 infection, ACE2levels, modulators of RAAS activity and the effects of RAAS modulators on ACE2 expression.

Protective role of ACE2 and its downregulation in SARS-CoV-2 infection leading to Macrophage Activation Syndrome: Therapeutic implications

In light of the outbreak of the 2019 novel coronavirus disease (COVID-19), the international scientific community has joined forces to develop effective treatment strategies. The Angiotensin-Converting Enzyme (ACE) 2, is an essential receptor for cell fusion and engulfs the SARS coronavirus infections. ACE2 plays an important physiological role, practically in all the organs and systems. Also, ACE2 exerts protective functions in various models of pathologies with acute and chronic inflammation. While ACE2 downregulation by SARS-CoV-2 spike protein leads to an overactivation of Angiotensin (Ang) II/AT1R axis and the deleterious effects of Ang II may explain the multiorgan dysfunction seen in patients. Specifically, the role of Ang II leading to the appearance of Macrophage Activation Syndrome (MAS) and the cytokine storm in COVID-19 is discussed below. In this review, we summarized the latest research progress in the strategies of treatments that mainly focus on reducing the Ang II-induced deleterious effects rather than attenuating the virus replication.

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Protective role of ACE2 in the organs and system

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Downregulation of ACE2 expression by SARS-CoV-2 leads to Ang II-induced organ damage.

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The appearance of MAS in COVID-19 patient

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Suggested treatment to diminish the deleterious effect of Ang II or appearance of MAS

Impact of Angiotensin II Signaling Blockade on Clinical Outcomes in Patients with Inflammatory Bowel Disease

BACKGROUND

Preclinical data demonstrate that activation of the renin-angiotensin system (RAS) contributes to mucosal inflammation, and RAS inhibition by angiotensin-converting-enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) improves colitis in animal models. Less is known regarding the effects of RAS inhibition on clinical outcomes in inflammatory bowel disease (IBD) patients.

AIM

Evaluate the impact of ACEI and ARB on clinical outcomes in IBD.

METHODS

Rates of IBD-related hospitalizations, operations, and corticosteroid use were evaluated retrospectively in two groups. First, 111 IBD patients taking an ACEI or ARB were compared to nonusers matched 1:1 based on sex, age, diagnosis, disease location, and hypertension diagnosis. Second, outcomes in a cohort of 130 IBD patients were compared prior to and during ACEI/ARB exposure.

RESULTS

Compared to matched controls, all IBD patients together with ACEI/ARB exposure had fewer hospitalizations (OR 0.26, p < 0.01), operations (OR 0.08, p = 0.02), and corticosteroid prescriptions (OR 0.5, p = 0.01). Comparing outcomes before and during ACEI/ARB use, there were no differences in hospitalizations, operations, or corticosteroid use for all IBD patients together, but patients with UC had increased hospitalizations (0.08 pre- vs. 0.16 during ACEI/ARB exposure, p = 0.03) and decreased corticosteroid use (0.24 pre-ACEI/ARB vs. 0.12 during ACEI/ARB exposure, p < 0.01) during ACEI/ARB use.

CONCLUSIONS

IBD patients with ACEI/ARB exposure had fewer hospitalizations, operations, and corticosteroid use compared to matched controls. No differences in outcomes were observed in individuals on ACEI/ARB therapy when compared to a period of time prior to medication exposure.

Captopril attenuates TAC-induced heart failure via inhibiting Wnt3a/β-catenin and Jak2/Stat3 pathways

Captopril (Cap) as angiotensin-converting enzyme inhibitor (ACEi) is commonly used to treat hypertension and some types of congestive heart failure. However, few studies reported on whether Cap exerts a protective effect on myocardial apoptosis induced by transverse aortic constriction (TAC). This study aimed at investigating the possible mechanism of Cap on myocardial apoptosis induced by pressure overload. Results showed that Cap significantly decreased heart-to-body weight ratios (HBWR). Cap markedly improved cardiac function, and reduced inner diameter of ascending aorta (Asc Ao) in TAC mice as shown by echocardiography. Enzyme-linked immunosorbent assay (ELISA) results demonstrated that Cap treatment also markedly decreased the level of N-terminal pro-B-type natriuretic peptide (NT-proBNP), atrial natriuretic peptide (ANP), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Cardiac pathological changes and fibrosis have been improved after Cap treatment as shown by hematoxylin-eosin (H&E) staining and Masson's trichrome staining. Moreover, Terminal deoxynucleotidyl transferase-mediated dexoxyuridine triphosphate nick-end labeling (TUNEL) staining result indicated Cap treatment also significantly inhibited cardiac apoptosis. Western Blot results showed that Cap obviously decreased the expression of cleaved capase-3, Bax, phosphorylated Jak2 (p-Jak2), phosphorylated Stat3 (p-Stat3), Wnt3a and β-catenin proteins, as well as increased Bcl-2 expression. In conclusion, Cap showed a protective effect on TAC-induced cardiac apoptosis, which could be attributed to the inhibition of Wnt3a/β-catenin signaling pathway. Cap also attenuated myocardial hypertrophy induced by TAC via suppression of Jak2/Stat3 pathway.

Angiotensins and rheumatoid arthritis

At present, the role of the renin-angiotensin system (RAS) in regulating the cardiovascular system and maintaining water and electrolyte homeostasis has been well studied. However, over the past decades, new components of the RAS have been identified, suggesting a wider range of its potential effects on the body. It is of fundamentally importance for rheumatologists to affect inflammation, including rheumatoid inflammation, through blockade of angiotensin (AT) II formation via the effects of AT 1–7 and angiotensin-converting enzyme inhibitors, as well as through suppression of angiogenesis, primarily by reducing the production of endothelial growth factor. The organ-protective and antiinflammatory potential of drugs that reduce the production of AT, which has been proven in in vitro and in vivo experiments, allows us to consider them as first-line angiotropic agents in patients with rheumatoid arthritis, especially in the presence of concomitant hypertension and/or nephropathy.

Malnutrition, inflamation and atherosclerosis (MIA syndrome) in patients with end stage renal disease on maintenance hemodialysis (a single centre experience)

BACKGROUND

Inflammation and malnutrition play an important role in endothelial dysfunction, atherosclerosis and excessive cardiovascular morbidity and mortality in ESRD patients AIM OF THE STUDY: The primary objective is to determine the prevalence of inflammation, malnutrition and atherosclerosis in patients on maintenance haemodialysis. Secondary objective was to determine the association for atherosclerosis with inflammation and malnutrition.

PATIENT AND METHODS

One hundred and one adult patients with end stage renal disease on maintenance haemodialysis who are met with the exclusion criteria were enrolled in this cross sectional study from haemodialysis unit of Baghdad teaching hospital over the period of July/2015 - June 2016. All patients were thoroughly examined and many variables were evaluated (age, gender, blood pressure, diabetes mellitus, serum lipid profile, smoking habits, serum albumin, CRP, calcium, Phosphate, Parathyroid hormone and haemoglobin measurements). All patients underwent a carotid Doppler ultrasound study.

RESULTS

Atherosclerosis was present in 65.3%: 58.4% of patients had malnutrition and 43.6% had inflammation. The association for atherosclerosis and high CRP and low serum albumin is strong and independent of other atherosclerosis risk factors. There is significant inverse and independent correlation between CRP and albumin.

CONCLUSION

Inflammation (high serum CRP) and malnutrition (low serum albumin) in patients on haemodialysis are significantly associated with carotid atherosclerosis. Inflammation was more prevalent in the malnourished patients than in those with normal nutritional status.

Therapy with intermittent pulse cyclophosphamide for pulmonary hypertension associated with systemic lupus erythematosus

The aim of this study was to compare the efficacy of intravenouscyclophosphamide(IVCYC) versus oral enalapril in mild or moderate pulmonary hypertension (PH) in systemic lupus erythematosus (SLE). Thirty-four patients with SLE who had systolic pulmonary artery pressure (SPAP) > 30mmHg by Doppler echocardiography were randomized to receive IVCYC (0.5g/mt2 body surface area, monthly), or oral enalapril (10mg/day) for six months. The primary outcome was the significant decrease in SPAP. An additional outcome measure included the improvement in the heart functional class (NYHA). Sixteen patients received cyclophosphamide and 18 enalapril. IVCYC decreased the median values of SPAP from 41 to 28mmHg (P < 0.001), and enalapril from 35 to 27mmHg (P 0.02). IVCYC reduced more than twice as much SPAP than enalapril (P 0.04). In those patients with SPAP ≥35mmHg, cyclophosphamidedecreased from 43 to 27mmHg (P 0.003), but enalapril was not effective (P 0.14). The NYHA functional class improved only in those with cyclophosphamide (P 0.021). Also IVCYC had a higher frequency of side effects including infections (RR 1.6; 95% CI, 1.001-2.47), and gastrointestinal side effects (RR 14.6; 95% CI,2.15-99.68). We concluded that IVCYC was effective in mild and moderate PH associated with SLE. Further research is needed to evaluate its long-term efficacy.

Angiotensin II in inflammation, immunity and rheumatoid arthritis

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that is characterized by increased cardiovascular morbidity and mortality, independent of the traditional risk factors for cardiovascular disease. Although classically known for its role in the regulation of circulatory homeostasis, angiotensin II (Ang II) is recognized to act as a powerful proinflammatory mediator. Some research has showed that Ang II plays important roles in autoimmune diseases, including RA, systemic lupus erythematosus and multiple sclerosis. Ang II blockers prove effective in reducing inflammation and autoimmunity in rheumatic diseases and their relative safety, together with their effects for reducing the cardiovascular disease risk, suggest that Ang II blockers may at least act as effective adjunctive therapy for disease control in patients with RA. The present review focuses systematically on the potential impact of Ang II and its receptors on inflammation and immunomodulation in patients with RA.

Kaposi's sarcoma: etiology and pathogenesis, inducing factors, causal associations, and treatments: facts and controversies

Kaposi's sarcoma (KS), an angioproliferative disorder, has a viral etiology and a multifactorial pathogenesis hinged on an immune dysfunction. The disease is multifocal, with a course ranging from indolent, with only skin manifestations to fulminant, with extensive visceral involvement. In the current view, all forms of KS have a common etiology in human herpesvirus (HHV)-8 infection, and the differences among them are due to the involvement of various cofactors. In fact, HHV-8 infection can be considered a necessary but not sufficient condition for the development of KS, because further factors (genetic, immunologic, and environmental) are required. The role of cofactors can be attributed to their ability to interact with HHV-8, to affect the immune system, or to act as vasoactive agents. In this contribution, a survey of the current state of knowledge on many and various factors involved in KS pathogenesis is carried out, in particular by highlighting the facts and controversies about the role of some drugs (quinine analogues and angiotensin-converting enzyme inhibitors) in the onset of the disease. Based on these assessments, it is possible to hypothesize that the role of cofactors in KS pathogenesis can move toward an effect either favoring or inhibiting the onset of the disease, depending on the presence of other agents modulating the pathogenesis itself, such as genetic predisposition, environmental factors, drug intake, or lymph flow disorders. It is possible that the same agents may act as either stimulating or inhibiting cofactors according to the patient’s genetic background and variable interactions.

Treatment guidelines for each form of KS are outlined, because a unique standard therapy for all of them cannot be considered due to KS heterogeneity. In most cases, therapeutic options, both local and systemic, should be tailored to the patient’s peculiar clinical conditions.

Angiotensin-converting enzyme and the tumor microenvironment: mechanisms beyond angiogenesis

The renin angiotensin system (RAS) is a network of enzymes and peptides that coalesce primarily on the angiotensin II type 1 receptor (AT1R) to induce cell proliferation, angiogenesis, fibrosis, and blood pressure control. Angiotensin-converting enzyme (ACE), the key peptidase of the RAS, is promiscuous in that it cleaves other substrates such as substance P and bradykinin. Accumulating evidence implicates ACE in the pathophysiology of carcinogenesis. While the role of ACE and its peptide network in modulating angiogenesis via the AT1R is well documented, its involvement in shaping other aspects of the tumor microenvironment remains largely unknown. Here, we review the role of ACE in modulating the immune compartment of the tumor microenvironment, which encompasses the immunosuppressive, cancer-promoting myeloid-derived suppressor cells, alternatively activated tumor-associated macrophages, and T regulatory cells. We also discuss the potential roles of peptides that accumulate in the setting of chronic ACE inhibitor use, such as bradykinin, substance P, and N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), and how they may undercut the gains of anti-angiogenesis from ACE inhibition. These emerging mechanisms may harmonize the often-conflicting results on the role of ACE inhibitors and ACE polymorphisms in various cancers and call for further investigations into the potential benefit of ACE inhibitors in some neoplasms.

Role of tissue factor in atherothrombosis

Tissue factor (TF) is abundantly present in atherosclerotic plaques and it is the primary source of TF that triggers the rapid activation of the coagulation cascade after plaque rupture. While much of this TF is associated with monocyte/macrophages and vascular smooth muscle cells, recent studies suggests TF-positive microparticles (MPs) are the most abundant source in plaques. Further, while intravascular TF is largely absent in healthy patients, cardiovascular disease patients have increased TF expression in circulating monocytes, which can result in increased levels of TF-positive MPs. This brief review describes how TF is the primary initiator of atherothrombosis and how TF-positive MPs may serve as a biomarker to identify patients at greater risk of forming an occlusive thrombus. In addition, currently used therapeutics, such as statins and inhibitors of the renin angiotensin system, may have additional benefits by reducing TF expression and subsequent thrombosis.

Chemical compositions and properties of Schinus areira L. essential oil on airway inflammation and cardiovascular system of mice and rabbits

The main purpose was to investigate the effects of essential plant-oil of Schinus areira L. on hemodynamic functions in rabbits, as well as myocardial contractile strength and airways inflammation associated to bacterial endotoxin lipopolysaccharide (LPS) in mice. This study shows the important properties of the essential oil (EO) of S. areira studied and these actions on lung with significant inhibition associated to LPS, all of which was assessed in mice bronchoalveolar lavage fluid and evidenced by stability of the percentage of alveolar macrophages, infiltration of polymorphonuclear leukocytes and tumor necrosis factor-α concentration, and without pathway modifications in conjugated dienes activity. Clinical status (morbidity or mortality), macroscopic morphology and lung/body weight index were unaffected by the administration of the EO S. areira. Furthermore, the ex vivo analysis of isolated hearts demonstrated the negative inotropic action of the EO of S. areira in a mice model, and in rabbits changes in the hemodynamic parameters, such as a reduction of systolic blood pressure. We conclude that EO S. areira could be responsible for modifications on the cardiovascular and/or airway parameters.

Dietary blue pigments derived from genipin, attenuate inflammation by inhibiting LPS-induced iNOS and COX-2 expression via the NF-κB inactivation

BACKGROUND AND PURPOSE

The edible blue pigments produced by gardenia fruits have been used as value-added colorants for foods in East Asia for 20 years. However, the biological activity of the blue pigments derived from genipin has not been reported.

METHODOLOGY/PRINCIPAL FINDINGS

The anti-inflammatory effect of blue pigments was studied in lipopolysaccharide (LPS) stimulated RAW 264.7 macrophage in vitro. The secretions of nitric oxide (NO) and prostaglandin E(2) (PGE(2)) were inhibited in concentration-dependent manner by blue pigments. Real-time reverse-transcription polymerase chain reaction (Real-time RT-PCR) analyses demonstrated that the mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin (IL)-6, and tumor necrosis factor alpha (TNF-α) was inhibited, moreover, ELISA results showed that the productions of IL-6 and TNF-α were inhibited. Cell-based ELISA revealed the COX-2 protein expression was inhibited. The proteome profiler array showed that 12 cytokines and chemokines involved in the inflammatory process were down-regulated by blue pigments. Blue pigments inhibited the nuclear transcription factor kappa-B (NF-κB) activation induced by LPS, and this was associated with decreasing the DNA-binding activity of p65 and p50. Furthermore, blue pigments suppressed the degradation of inhibitor of κB (IκB) α, Inhibitor of NF-κB Kinase (IKK) α, IKK-β, and phosphorylation of IκB-α. The anti-inflammatory effect of blue pigments in vivo was studied in carrageenan-induced paw edema and LPS-injecting ICR mice. Finally, blue pigments significantly inhibited paw swelling and reduced plasma TNF-α and IL-6 production in vivo.

CONCLUSIONS AND IMPLICATIONS

These results suggest that the anti-inflammatory properties of blue pigments might be the results from the inhibition of iNOS, COX-2, IL-6, IL-1β, and TNF-α expression through the down-regulation of NF-κB activation, which will provide strong scientific evidence for the edible blue pigments to be developed as a new health-enhancing nutritional food for the prevention and treatment of inflammatory diseases.

Drug therapy of heart failure: an immunologic view

Heart failure (HF) is a clinical syndrome manifested by signs and symptoms of low cardiac output, pulmonary, and/or systemic congestion. Immunologically, HF is defined as a state of immune activation and persistent inflammation, especially the circulatory levels of inflammatory cytokines have been found to increase. Traditional drugs used in HF have expressed immunomodulatory and/or anticytokine activities that may participate in their therapeutic efficacy in the disease. The angiotensin-converting enzyme inhibitors like captopril and enalapril as well as the angiotensin II receptor antagonist losartan indicated in HF exerted reducing effects on the inflammatory cytokines such as tumor necrosis factor-alpha and interleukin-6 at experimental and clinical levels. Aldosterone antagonists like spironolactone when administered concomitantly with losartan can attenuate angiotensin II-enhanced cytokine production in HF. Carvedilol beta-adrenergic blockers showed a wider spectrum of anti-inflammatory/anticytokine activity that proved to be associated with improvement of cardiac function and ejection fraction in patients with HF. The poor prognosis in HF despite the long experience with its treatment necessitated thinking about new drugs to be added to the traditional ones. Methotrexate and statins are examples of these drugs, especially because they exert immunologic effects. A low dose of methotrexate has been considered as a hopeful adjunct therapy in chronic HF, but large long-term clinical trials are required. Statins showed conflicting results, although they might be useful early after acute ischemic events associated with left ventricular dysfunction or failure, especially in younger patients with less advanced HF.

Therapeutic effect of captopril, pentoxifylline, and cordyceps sinensis in pre-hepatic portal hypertensive rats

BACKGROUND/AIM

Portal hypertension is an important and potentially fatal complication of liver disease whereby cellular and fibrotic alterations manifest to increase portal venous pressure. The aim of this study is to investigate the effect of captopril, pentoxifylline (PTX), and cordyceps sinensis in pre-hepatic portal hypertensive rats.

SETTINGS AND DESIGN

Wistar male rats were divided at random into 3 main groups: the first group: control rats. The second group: sham-operated rats and the third group: prehepatic portal hypertensive rats (PHPHT) induced by regulated pre-hepatic portal vein ligation. After 14 days, Group 3 was subdivided into 5 subgroups. Subgroup (1): portal vein-ligated (PVL) was killed at once; Subgroup (2): received distilled water for 30 days (untreated PVL group); subgroups 3-5 were treated with captopril (60 mg/kg, orally); PTX (100 mg/kg, orally); and C. sinensis (200 mg/kg, orally), respectively, as a single daily dose for 30 days.

PATIENTS AND METHODS

Portal pressure, nitric oxide (NO), antioxidant enzymes, Liver enzymes, and creatinine levels were measured to evaluate the status of the liver state.

RESULTS

Portal vein ligation produced significant increments in liver enzymes, NO, creatinine and portal pressure concomitant with significant decrements in glutathione content and superoxide dismutase activity. Treatment with captopril, PTX, and C. sinensis resulted in a significant reduction in liver enzymes, NO, creatinine and portal pressure and observable increase in antioxidant enzymes.

CONCLUSIONS

captopril, PTX, and C. sinensis have promising effect in controlling PHPHT and reducing hyperdynamic circulatory state through reduction of portal pressure and NO level.

In vitro and in vivo anti-inflammatory activity of 17-O-acetylacuminolide through the inhibition of cytokines, NF-κB translocation and IKKβ activity

BACKGROUND AND PURPOSE

17-O-acetylacuminolide (AA), a diterpenoid labdane, was isolated for the first time from the plant species Neouvaria foetida. The anti-inflammatory effects of this compound were studied both in vitro and in vivo.

EXPERIMENTAL APPROACH

Plant extracts were initially tested against LPS-stimulated release of tumor necrosis factor alpha (TNF-α) from murine macrophages (RAW264.7 cells). Based on bioassay-guided fractionation, the active compound was identified as AA. AA was tested for its ability to reduce nitric oxide (NO) production, and the inducible nitric oxide synthase (iNOS) expression. The inhibition of a panel of inflammatory cytokines (TNF, IL-1β, IL-6, KC, and GM-CSF) by AA was assessed at the expression and the mRNA levels. Moreover, the effect of AA on the translocation of the transcription factor nuclear factor kappa B (NF-κB) was evaluated in LPS-stimulated RAW264.7 cells and in TNF-stimulated L929 cells. Subsequently, AA was tested in the inhibitor of NF-κB kinase beta (IKKβ) activity assay. Lastly, the anti-inflammatory activity of AA in vivo was evaluated by testing TNF production in LPS-stimulated Balb/c mice.

KEY RESULTS

AA effectively inhibited TNF-α release with an IC(50) of 2.7 µg/mL. Moreover, AA significantly inhibited both NO production and iNOS expression. It significantly and dose-dependently inhibited TNF and IL-1β proteins and mRNA expression; as well as IL-6 and KC proteins. Additionally, AA prevented the translocation of NF-κB in both cell lines; suggesting that it is acting at a post receptor level. This was confirmed by AA's ability to inhibit IKKβ activity, a kinase responsible for activating NF-κB, hence providing an insight on AA's mechanism of action. Finally, AA significantly reduced TNF production in vivo.

CONCLUSIONS AND IMPLICATIONS

This study presents the potential utilization of this compound, as a lead for the development of an anti-inflammatory drug.

Intestinal intraepithelial lymphocyte derived angiotensin converting enzyme modulates epithelial cell apoptosis

BACKGROUND & AIMS

Intestinal adaptation in short bowel syndrome (SBS) consists of increased epithelial cell (EC) proliferation as well as apoptosis. Previous microarray analyses of intraepithelial lymphocytes (IEL) gene expression after SBS showed an increased expression of angiotensin converting enzyme (ACE). Because ACE has been shown to promote alveolar EC apoptosis, we examined if IEL-derived ACE plays a role in intestinal EC apoptosis.

METHODS

Mice underwent either a 70% mid-intestinal resection (SBS group) or a transection (Sham group) and were studied at 7 days. ACE expression was measured, and ACE inhibition (ACE-I, enalaprilat) was used to assess ACE function.

RESULTS

IEL-derived ACE was significantly elevated in SBS mice. The addition of an ACE-I to SBS mice resulted in a significant decline in EC apoptosis. To address a possible mechanism, tumor necrosis factor alpha (TNF-alpha) mRNA expression was measured. TNF-alpha was significantly increased in SBS mice, and decreased with ACE-I. Interestingly, ACE-I was not able to decrease EC apoptosis in TNF-alpha knockout mice.

CONCLUSIONS

This study shows a previously undescribed expression of ACE by IEL. SBS was associated with an increase in IEL-derived ACE. ACE appears to be associated with an up-regulation of intestinal EC apoptosis. ACE-I significantly decreased EC apoptosis.

Effect of angiotensin-converting enzyme inhibition and angiotensin II type 1 receptor blockade on apoptotic changes in contralateral testis following unilateral testicular torsion

OBJECTIVES

In this experimental study, our aim was to determine whether angiotensin-converting enzyme (ACE) inhibition and angiotensin II type 1 (AT1) receptor blockade affect the apoptotic changes in contralateral testis following unilateral testicular torsion (UTT).

METHODS

Study groups consisted of 30 adult male Wistar rats. The rats were randomly separated into five groups. Group 1 was maintained as control without manipulation. Group 2 underwent the sham operation. Torsion was created by rotating the left testis 720 degrees clockwise for 4 h and maintained by fixing the testis to the scrotum in the other groups. Group 3 underwent torsion and detorsion, with saline administration after detorsion. In group 4, the same surgical procedure was done as in the detorsion group, but AT1 receptor blocker (losartan 30 mg/kg) was injected intraperitoneally for 60 min before detorsion. In group 5, the same surgical procedure was done as in the detorsion group, but ACE inhibitor (lisinopril 50 mg/kg) was injected intraperitoneally for 60 min before detorsion. Bilateral testes were removed from each rat 24 h after surgery. Apoptosis was assessed in paraffin-embedded sections stained for TUNEL method. Reticulum staining was performed to evaluate the extracellular changes semiquantitatively. Testicular biopsy score counts were performed on these sections according to Johnsen.

RESULTS

The mean apoptotic scores of group 1, group 2 and group 3 were significantly higher than that of the other groups. There was no difference between the apoptotic scores of groups 1, 2, 4 and 5. Reticulum stain was increased in group 3 as compared to other groups. The mean Johnsen biopsy score of group 3 was significantly lower than that of the other groups.

CONCLUSION

ACE inhibition and AT1 receptor blockade reduced the tubular damage and apoptosis in the contralateral testes after UTT. The beneficial effect of these drugs may arise from inhibition of ischemic process resulting from increased sympathetic activity and elimination of insults subsequent to dysregulation of RAS. These results suggest that ACE inhibitors and AT1 receptor blockers may be of potential value in patients with UTT.

Anti-inflammatory effect of angiotensin type 1 receptor antagonist on endotoxin-induced uveitis in rats

BACKGROUND

Angiotensin II type 1 (AT1) receptor-antagonists are widely used for treatment of hypertension. Recent studies have demonstrated a protective effect of renin angiotensin system (RAS) antagonism against immune-mediated inflammatory diseases such as myocarditis, chronic allograft rejection, antiglomerular basement membrane nephritis, colitis, and arthritis. However, only a few reports have demonstrated the effect of RAS in ocular inflammatory conditions. The purpose of this study was to investigate the anti-inflammatory effect of a selective AT1 receptor antagonist, losartan, on endotoxin-induced uveitis (EIU) and compare the effect on experimental autoimmune uveoretinitis (EAU).

METHODS

To induce EIU, 7-week-old Lewis rats were injected subcutaneously with 200 microg lipopolysaccharide (LPS). Losartan was administered intravenously at the same time. The aqueous humor was collected from eyes 24 h after LPS injection. The number of infiltrating cells, protein concentration, and levels of tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein-1 (MCP-1) in the aqueous humor were determined. The collected eyes were immunohistochemically stained with monoclonal antibody for activated nuclear factor (NF)-kappaB. To induce EAU, C57BL/6 mice (6-8 weeks old) were immunized with human interphotoreceptor retinoid binding protein (hIRBP)-derived peptide emulsified in complete Freund's adjuvant (CFA) and concomitantly injected with purified Bordetella pertussis toxin (PTX). Clinical severity of EAU and T cell proliferative response were analyzed.

RESULTS

Losartan significantly suppressed the development of EIU. Numbers of aqueous cells of control EIU rats, those from EIU rats treated with 1 or 10 mg/kg of losartan were 75.3+/-45.6 x 10(5), 27.9+/-8.1 x 10(5), or 41.3+/-30.9 x 10(5) cells/ml respectively (p<0.01 vs control). Aqueous protein, TNF-alpha, and MCP-1 levels were also significantly decreased in a manner dependent on the amount of losartan administered (p<0.01). Treatment of EIU rats with losartan suppressed activation of NF-kappaB at the iris ciliary body. Thus, the suppressive effect of losartan on ocular inflammation in EIU appeared to result from down-regulation of NF-kappaB activation and reduction of inflammatory cytokine production. On the other hand, in the EAU model, neither the clinical score nor the antigen-specific T cell proliferative response was significantly influenced by the treatment with losartan.

CONCLUSIONS

The present findings indicate that RAS may be involved in the acute inflammation of the eye, but not in T cell-dependent ocular autoimmunity. Antagonism of the RAS may be a potential prophylactic strategy for treatment of the human acute ocular inflammation.

Effects of angiotensin II blockade on the development of autoimmune thyroiditis in nonobese diabetic mice

We evaluated the effects of angiotensin II (Ang II) blockers, losartan, an Ang II receptor blocker, and enalapril, an angiotensin converting enzyme inhibitor, on the development of autoimmune thyroiditis in nonobese diabetic (NOD) mice, an animal model of Hashimoto's thyroiditis (HT). Mice were assigned into three groups, untreated, losartan-treated (30 mg/kg/day), and enalapril-treated (10 mg/kg/day) groups. Thyroiditis was induced by iodide ingestion (experiment 1) or mouse thyroglobulin (Tg) immunization (experiment 2). Both procedures effectively induced thyroiditis. While iodide ingestion failed to induce anti-mouse Tg antibody (TgAb) production, Tg immunization resulted in a significant increase in serum TgAb levels. In both experiments, neither losartan nor enalapril interfered with the development of thyroiditis and TgAb production. These results suggest that Ang II may not be associated with the development of autoimmune thyroiditis in NOD mice. Thus, the Ang II blockade may not have therapeutic potential in HT.

Anti-inflammatory actions of quinapril

OBJECTIVE

The role of angiotensin II (Ang-II) in inflammation and the mechanisms through which it exerts this role are explored. Signaling through angiotensin stimulation of inflammatory cells often amplifies inflammation. Formation of Ang-II from tissue angiotensin-converting enzyme (ACE) has been shown to be of greater importance in the development and progression of inflammatory diseases than plasma ACE.

CONCLUSION

Quinapril, which is a potent and selective inhibitor of both plasma and tissue ACE, has demonstrated anti-inflammatory properties in many disease states such as atherosclerosis, nephritis, scleroderma, diabetes and arthritis, and, thus, offers new therapeutic possibilities for disease treatment.

Captopril suppresses inflammation in endotoxin-induced uveitis in rats

Captopril is an inhibitor of angiotensin-converting enzyme (ACE) that is largely used in the treatment of cardiovascular diseases. Several previous studies have demonstrated that captopril exhibits a wide variety of biological activities, including an anti-inflammatory action, on which we focused our attention. The aim of the present study was to investigate the efficacy of captopril on endotoxin induced uveitis (EIU) in rats. We investigated its effect upon cellular infiltration and protein leakage, as well as on the concentration of tumor necrosis factor-alpha (TNF-alpha), nitric oxide (NO), prostaglandin E2 (PGE2), monocyte chemoattractant protein-1 (MCP-1) in the anterior chamber. In addition, we checked its effect on activation of nuclear factor kappa B (NF-kappaB) in iris and ciliary body (ICB) cells in vivo. EIU was induced in male Lewis rats by a footpad injection of lipopolysaccharide (LPS). One hour after the LPS inoculation, either 1mg/kg, 10mg/kg or 100mg/kg captopril were injected intravenously. 24h later, the aqueous humor was collected from both eyes, and the number of infiltrating cells and protein concentration in the aqueous humor were determined. Levels of TNF-alpha, PGE2, NO and MCP-1 were determined by enzyme-linked immunosorbent assay. On some eyes, after enucleation, immunohistochemical staining with a monoclonal antibody against activated NF-kappaB was performed. Captopril treatment significantly decreased the inflammatory cells infiltration, the level of protein, concentrations of TNF-alpha, PGE2, NO and MCP-1 in the aqueous humor. The number of activated NF-kappaB-positive cells was lower in ICB of the rats treated with captopril 3h after the LPS injection. The present results indicate that captopril suppresses the inflammation in EIU by inhibiting the NF-kappaB-dependent pathway and the subsequent production of pro-inflammatory mediators.

Psoriatic erythroderma associated with enalapril

A 59-year-old man with a 35-year personal and positive family history of psoriasis was admitted to our department for treatment of psoriatic erythroderma. The patient had commenced therapy with enalapril 10 mg b.i.d. for the treatment of hypertension approximately 6 weeks before hospitalization. Five weeks after the initiation of enalapril, his psoriasis began to flare, and for a period of about 1 week it reached the extent of erythroderma. The patient did not associate the psoriatic flare with other factors such as infections, trauma, or stress. The patient presented with diffuse erythema and pronounced desquamation covering his entire trunk, scalp, and extremities (Figure). Nearly 100% of the body surface area was involved. The palms and soles were also affected, displaying erythema, hyperkeratosis, and painful fissures. The nails showed pits, oil spots, and subungual hyperkeratosis. The patient also had psoriatic arthritis affecting the interphalangeal joints of his fingers. Laboratory tests revealed an elevated erythrocyte sedimentation rate, an elevated creatinine level of 180 mmol/L, a blood urea nitrogen level of 10.8 mmol/L, and a uric acid level of 716 mmol/L. Urinalysis showed proteinuria of 1.5 g/24 h. The patient's renal condition was diagnosed as chronic tubulointerstitial nephritis, most probably related to his dermatologic disease. Allopurinol and dietary measures were recommended. Following treatment with methotrexate and replacement of enalapril therapy, the erythema and scaling gradually subsided and became confined to his pre-eruptive chronic plaques (approximately 5% of body surface area). Rechallenge with enalapril was not performed.

Disease modification and cardiovascular risk reduction: two sides of the same coin?

Inflammatory rheumatic diseases are associated with a substantial increase in accelerated atherosclerosis, with complex interactions between traditional and disease-related risk factors. Therefore, cardiovascular risk reduction should be considered as integral to the control of disease activity in the care plans of patients with RA, SLE and, arguably any chronic inflammatory disease. Shared care structures, already established for the monitoring of DMARDs, could be adapted to communicate and monitor cardiovascular risk reduction objectives. We review the evidence for the efficacy of a range of therapeutic strategies, the majority of which impact on both disease activity and cardiovascular risk. The algorithm proposed here attempts to distil the latest advice from specialist panels at the National Cholesterol Education Program and the British Hypertension Society, as well as incorporating the existing data on SLE and RA patients. The algorithm is structured to minimize clinic time and resources necessary to stratify patients into groups for ROUTINE, SUBSTANTIAL or INTENSIVE risk management; the associated table summarizes optimal therapeutic objectives in each of these groups. The implication of this algorithm is that management of cardiovascular risk should be much more aggressive than is currently the norm in patients with chronic inflammatory diseases, such as RA and SLE. Long-term studies of such interventions are needed to further clarify the benefits of intensive cardiovascular risk management in these patients.

AT1 receptor blocker added to ACE inhibitor provides benefits at advanced stage of hypertensive diastolic heart failure

Diastolic heart failure (DHF) has become a social burden; however, evidences leading to its therapeutic strategy are lacking. This study investigated effects of addition of angiotensin II type 1 receptor blocker (ARB) to angiotensin-converting enzyme inhibitor (ACEI) at advanced stage of DHF in hypertensive rats. Dahl salt-sensitive rats fed 8% NaCl diet from age 7 weeks served as DHF model, and those fed a normal chow served as control. The DHF model rats were arbitrarily assigned to 3 treatment regimens at age 17 weeks: ACEI (temocapril 0.4 mg/kg per day), combination of ACEI (temocapril 0.2 mg/kg per day) with ARB (olmesartan 0.3 mg/kg per day), or placebo. At age 17 weeks, this model represents progressive ventricular hypertrophy and fibrosis, relaxation abnormality, and myocardial stiffening. Data were collected at age 20 weeks. As compared with the monotherapy with ACEI, the addition of ARB induced more prominent suppression of ventricular hypertrophy and fibrosis, leading to suppression of myocardial stiffening, improvement of relaxation, and inhibition of hemodynamic deterioration. Such benefits were associated with greater decreases in reactive oxygen species (ROS) generation, macrophage infiltration, and gene expression of transforming growth factor (TGF)-beta(1) and interleukin (IL)-1beta, but not with changes in gene expression of monocyte chemoattractant protein (MCP)-1 and tumor necrosis factor (TNF)-alpha. Thus, ARB added to ACEI provides more benefits as compared with ACEI alone in DHF when initiated at an advanced stage. The additive effects are likely provided through more prominent suppression of ROS generation and inflammatory changes without effects on expression of MCP-1 and TNF-alpha.

Attenuation of virus-induced myocardial injury by inhibition of the angiotensin II type 1 receptor signal and decreased nuclear factor-kappa B activation in knockout mice

OBJECTIVES

This study examined the role of angiotensin II (Ang-II) in a murine model of viral myocarditis.

BACKGROUND

Ang-II plays an important role in the pathophysiology of various cardiovascular disorders. However, the role of Ang-II in inflammatory heart diseases is not known.

METHODS

Four-week-old wild-type (WT) and Ang-II type 1 receptor (AT(1)R) knockout (KO) mice were inoculated with the encephalomyocarditis virus (EMCV). Survival, histopathology, expression of proinflammatory cytokines, and activity of nuclear factor-kappa B (NF-kB) in the heart were examined.

RESULTS

The 14-day survival was significantly increased in KO compared with WT mice. Histopathologic scores for myocardial necrosis (0.86 +/- 0.69 vs. 2.44 +/- 0.88, p < 0.01) and cellular infiltration (0.86 +/- 0.38 vs. 2.33 +/- 0.50, p < 0.01) were lower in KO than in WT mice. The expression of tumor necrosis factor-alpha (TNF-alpha) was increased 43.2-fold, that of interleukin-1-beta (IL-1-beta) 45.8-fold, and the activity of NF-kB 2.24-fold by EMCV inoculation in WT mice (each p < 0.01), but not in KO mice (5.9-fold, 6.3-fold, and 1.12-fold, respectively, each p = NS). The AT(1)R blocker also significantly attenuated the expression of proinflammatory cytokines and the activation of NF-kB in virus-inoculated WT mice. Intravenous Ang-II injection enhanced the activation of NF-kB (2.28-fold, p < 0.01) and increased the expression of TNF-alpha (2.31-fold, p < 0.01) and IL-1-beta (2.45-fold, p < 0.01) in heart tissue of WT but not KO mice.

CONCLUSIONS

These results indicate that the AT(1)R signal is obligatory for the development of virus-induced myocardial injury through the proinflammatory action of Ang-II via the NF-kB/cytokine pathway.

Captopril prevents experimental autoimmune myocarditis

Captopril, an angiotensin-converting enzyme inhibitor, is widely used in the treatment of a variety of cardiomyopathies, but its effect on autoimmune myocarditis has not been addressed experimentally. We investigated the effect of captopril on myosin-induced experimental autoimmune myocarditis. A/J mice, immunized with syngeneic cardiac myosin, were given 75 mg/L of captopril in their drinking water. Captopril dramatically reduced the incidence and severity of myocarditis, which was accompanied by a reduction in heart weight to body weight ratio and heart weight. Captopril specifically interfered with cell-mediated immunity as myosin delayed-type hypersensitivity (DTH) was reduced, while anti-myosin Ab production was not affected. Captopril-treated, OVA-immunized mice also exhibited a decrease in OVA DTH. In myosin-immunized, untreated mice, injection of captopril directly into the test site also suppressed myosin DTH. Interestingly, captopril did not directly affect Ag-specific T cell responsiveness because neither in vivo nor in vitro captopril treatment affected the proliferation, IFN-gamma secretion, or IL-2 secretion by Ag-stimulated cultured splenocytes. These results indicate that captopril ameliorates experimental autoimmune myocarditis and may act, at least in part, by interfering with the recruitment of cells to sites of inflammation and the local inflammatory environment.

Minireview: adiposity, inflammation, and atherogenesis

Adipose tissue is a dynamic endocrine organ that secretes a number of factors that are increasingly recognized to contribute to systemic and vascular inflammation. Several of these factors, collectively referred to as adipokines, have now been shown regulate, directly or indirectly, a number of the processes that contribute to the development of atherosclerosis, including hypertension, endothelial dysfunction, insulin resistance, and vascular remodeling. Several adipokines are preferentially expressed in visceral adipose tissue, and the secretion of proinflammatory adipokines is elevated with increasing adiposity. Not surprisingly, approaches that reduce adipose tissue depots, including surgical fat removal, exercise, and reduced caloric intake, improve proinflammatory adipokine levels and reduce the severity of their resultant pathologies. Systemic adipokine levels can also be favorably altered by treatment with several of the existing drug classes used to treat insulin resistance, hypertension, and hypercholesterolemia. Greater understanding of adipokine regulation, however, should result in the design of improved treatment strategies to control disease states associated with increase adiposity, an important outcome in view of the growing worldwide epidemic of obesity.

Inflammation, arteriosclerosis, and cardiovascular therapy in hemodialysis patients

BACKGROUND

Aortic stiffness and left ventricular hypertrophy (LVH) are predictors of mortality in hemodialysis (HD) patients. Attenuation of arterial stiffness and regression of LVH had a favorable effect on survival in these patients, but this favorable effect was observed in less than 50% of patients, the rest being resistant to therapeutical interventions. The aim of this study was to analyze the factors associated with this resistance to treatment.

METHODS

138 patients on HD were studied during a follow-up survey. From entry until the end of follow up, the changes of aortic pulse wave velocity (PWV) and of LV mass were measured in response to treatment with antihypertensive drugs and erythropoietin, together with measurements of blood chemistry, including high-sensitive C-reactive protein (CRP). Patients with decreased aortic PWV were considered to be responders (N = 68), the others to be nonresponders (N = 70).

RESULTS

Nonresponders were older (P < 0.05) and had persistently higher systolic blood pressure (BP) and pulse pressure. Responders were treated more frequently with an ACE inhibitor (P < 0.001), and had lower serum CRP (P < 0.01). The baseline PWV, as well as the changes of PWV and LV mass during the follow-up were significantly and independently correlated with serum CRP level (P < 0.001). According to logistic regression after adjustment for age, gender, diabetes, history of CVD, and the nonspecific cardiovascular risk factors, the improvement of aortic stiffness and LV hypertrophy was positively associated with prescription of ACE inhibitor (P < 0.0001), and negatively with the serum CRP level (P < 0.01).

CONCLUSION

These results indicate that in HD patients, the presence of low-grade inflammation decreases the efficiency of cardiovascular therapeutic interventions and participates in the persistence of cardiovascular hemodynamic overload.

Cellular targets for angiotensin II fragments: pharmacological and molecular evidence

Although angiotensin II has long been considered to represent the end product of the renin-angiotensin system (RAS), there is accumulating evidence that it encompasses additional effector peptides with diverse functions. In this respect, angiotensin IV (Ang IV) formed by deletion of the two N terminal amino acids, has sparked great interest because of its wide range of physiological effects. Among those, its facilitatory role in memory acquisition and retrieval is of special therapeutic relevance. High affinity binding sites for this peptide have been denoted as AT(4)- receptors and, very recently, they have been proposed to correspond to the membrane-associated OTase/ IRAP aminopeptidase. This offers new opportunities for examining physiological roles of Ang IV in the fields of cognition, cardiovascular and renal metabolism and pathophysiological conditions like diabetes and hypertension. Still new recognition sites may be unveiled for this and other angiotensin fragments. Recognition sites for Ang-(1-7) (deletion of the C terminal amino acid) are still elusive and some of the actions of angiotensin III (deletion of the N terminal amino acid) in the CNS are hard to explain on the basis of their interaction with AT(1)-receptors only. A more thorough cross-talk between in vitro investigations on native and transfected cell lines and in vivo investigations on healthy, diseased and transgenic animals may prove to be essential to further unravel the molecular basis of the physiological actions of these small endogenous angiotensin fragments.

Chronic heart failure and the immune system

Several lines of evidence support a role of immune mechanisms in the pathogenesis of chronic heart failure (CHF). Proinflammatory cytokines (interleukin-1, -2, -6, and tumor necrosis factor) and chemokines are involved in cardiac depression and in the progression of heart failure. Other components believed to be relevant to the pathogenesis of CHF are adhesion molecules, autoantibodies, nitric oxide (NO), and endothelin-1. The origin of the immune activation in patients with CHF is still unknown, however two hypotheses have been proposed on the basis of experimental and clinical data. One suggests that the bowel wall edema leads to bacterial translocation with subsequent endotoxin release and immune activation. The second suggests that the heart in CHF is the main source of cytokines, as is shown by the fact that TNF alpha is produced by the failing myocardium but not by a normal one. No single source of cytokine production (gut or heart) seems sufficient to fully explain the multiple organ involvement and the systemic inflammation of CHF, which is probably related to systemic hypoxia, a potent stimulus for activation of the immune system and for cytokine production. The effort of define the immune system's role has opened new perspectives of therapeutic strategies, such as anti-cytokine drugs, to treat CHF.

Angiotensin II regulates the synthesis of proinflammatory cytokines and chemokines in the kidney

BACKGROUND

Emerging evidence suggests that angiotensin II (Ang II) is not only a vasoactive peptide, but also a true cytokine that regulates cell growth, inflammation and fibrosis. Many studies have demonstrated that this peptide plays an active role in the progression of renal injury. Some of Ang II-induced effects are mediated by the production of a large array of growth factors. The aim of this study was to investigate whether Ang II could regulate the expression of cytokines and chemokines in the kidney and its correlation with the Ang II-induced renal damage.

METHODS

The model of Ang II-induced renal damage was done by systemic Ang II infusion into normal rats (50 ng/kg/min; subcutaneous osmotic minipumps). In addition, the implication of Ang II was investigated in a model of immune complex nephritis in rats treated with the angiotensin converting enzyme (ACE) inhibitor quinapril. The mRNA expression was analyzed by RT-PCR and/or Northern blot, and protein levels by Western blot and/or immunohistochemistry.

RESULTS

Rats infused with Ang II for 3 days caused elevated renal expression of tumor necrosis factor-alpha (TNF-alpha; gene and protein levels). TNF-alpha positive cells were observed in glomeruli (mainly in endothelial cells), tubules and vessels. In rats with immune complex nephritis, the renal overexpression of TNF-alpha was diminished by the ACE inhibitor quinapril. Systemic infusion of Ang II also increased renal synthesis of cytokines (interleukin-6, IL-6) and chemokines (monocyte chemoattractant protein-1; MCP-1) that were associated with elevated tissue levels of activated nuclear factor-kappaB (NF-kappaB) and the presence of inflammatory cell infiltration.

CONCLUSIONS

Ang II in vivo increases TNF-alpha production in the kidney. Ang II also up-regulates other proinflammatory mediators, including IL-6, MCP-1 and NF-kappaB, coincidentally associated to the presence of glomerular and interstitial inflammatory cells in the kidney. All these data further strengthen the idea that Ang II plays an active role in the inflammatory response in renal diseases.

Inflammation in end-stage renal disease: sources, consequences, and therapy

Cardiovascular disease (CVD) remains the main cause of morbidity and mortality in patients with end-stage renal disease (ESRD). Although traditional risk factors are common in ESRD patients, they alone may not be sufficient to account for the high prevalence of CVD in this condition. Recent evidence demonstrates that chronic inflammation, a nontraditional risk factor which is commonly observed in ESRD patients, may cause malnutrition and progressive atherosclerotic CVD by several pathogenetic mechanisms. The causes of inflammation in ESRD are multifactorial and, while it may reflect underlying CVD, an acute-phase reaction may also be a direct cause of vascular injury by several pathogenetic mechanisms. Available data suggest that proinflammatory cytokines play a central role in the genesis of both malnutrition and CVD in ESRD. Thus it could be speculated that suppression of the vicious cycle of malnutrition, inflammation, and atherosclerosis (MIA syndrome) would improve survival in dialysis patients. Recent evidence has demonstrated strong associations between inflammation and both increased oxidative stress and endothelial dysfunction in ESRD patients. As there is not yet any recognized, or even proposed, treatment for ESRD patients with chronic inflammation, it would be of obvious interest to study the long-term effect of various anti-inflammatory treatment strategies on the nutritional and cardiovascular status as well as outcome in these patients.

Activation and suppression of renin-angiotensin system in human dendritic cells

We previously identified the gene expression of renin-angiotensin system in human monocyte-derived dendritic cells (DCs). This study was conducted to examine the mechanisms by which angiotensin II and captopril, the inhibitor of the angiotensin-converting enzyme (ACE), affect human DCs. In DCs, lipopolysaccharide (LPS)-induced production of tumor necrosis factor-alpha (TNF-alpha), interleukin-(IL)-1alpha, IL-10, IL-12, and IL-18 was significantly inhibited by captopril. In contrast, angiotensin II treatment resulted in a significant increase in TNF-alpha and IL-6 protein biosynthesis by DCs. In addition, we have studied the global expression of 2400 genes in DCs from two donors. Here, we demonstrated the specific down-regulation of the ACE gene expression in captopril-treated DCs. Our finding indicates the possible activation of NF-kappaB through the up-regulation of expressions of MEFV gene (encoding PYRIN protein) and heterogeneous nuclear ribonucleoprotein R in DCs. This is the first study on the modulation of cytokine and gene expression by angiotensin II and captopril in DCs.

Captopril-impaired production of tumor necrosis factor-alpha-induced interleukin-1beta in human monocytes is associated with altered intracellular distribution of nuclear factor-kappaB

We evaluated the effects of the angiotensin-converting enzyme (ACE) inhibitor captopril on pathways for monocyte production of interleukin (IL)-1beta in vitro. Human monocytes were treated with captopril and stimulated with tumor necrosis factor (TNF)-alpha or lipopolysaccharide. Captopril caused a dose-dependent reduction of TNF-alpha induced IL-1beta. LPS-induced IL-1beta generation was not reduced by the ACE inhibitor. Pro-IL-1beta concentrations followed the same pattern as that for mature IL-1beta when monocytes were preincubated with captopril. Also, IL-1beta mRNA concentrations were reduced by captopril pretreatment in parallel with IL-1beta. We sought to determine whether captopril affected the nuclear factor (NF)-kappaB complex in monocytic cells. We found that the translocation of the p-65 component of NF-kappaB to the nucleus was inhibited by captopril. Thus captopril reduced TNF-alpha-induced IL-1beta and IL-1betamRNA synthesis in monocytes, in vitro, probably through interference with NF-kappaB activation of the IL-1beta gene. These results support the hypothesis that captopril has immunomodulating properties.