Increased angiotensin II type 1 receptor expression in temporal arteries from patients with giant cell arteritis

Angiotensin receptor blockade is associated with increased risk of giant cell arteritis

OBJECTIVES

Angiotensin II is implicated in GCA pathology. We examined whether the use of angiotensin receptor blockers (ARBs) is associated with GCA risk compared with angiotensin-converting enzyme inhibitors (ACEis) or other antihypertensives.

METHODS

We performed a matched cohort study including adults who were initiators of antihypertensives in UK primary care data between 1995 and 2019. Treatment-naïve individuals without prior GCA or PMR were categorized into three groups-ARB initiators, ACEi initiators, or other antihypertensive initiators (beta-blockers, calcium channel blockers, diuretics or alpha-adrenoceptor blockers)-and followed for up to 5 years. Incident GCA was defined using validated Read codes, with age of onset ≥50 years and two or more glucocorticoid prescriptions. Inverse probability-weighted Cox models were used to model outcome risk, adjusting for lifestyle parameters, comorbidities and comedications.

RESULTS

Among >1 million new starters of antihypertensives (81 780 ARBs, 422 940 ACEis and 873 066 other antihypertensives), the incidence rate of GCA per 10 000 patient-years was 2.73 (95% CI 2.12, 3.50) in the ARB group, 1.76 (95% CI 1.25, 2.39) in the ACEi group and 1.90 (95% CI 1.37, 2.56) in the other antihypertensives group. The hazard of GCA was higher in ARB initiators [hazard ratio (HR) 1.55; 95% CI 1.16, 2.06] than initiators of ACEis, but similar between initiators of other antihypertensives and ACEis (HR 1.08; 95% CI 0.87, 1.35).

CONCLUSIONS

Initiation of ARBs is associated with a higher risk of GCA compared with ACEis or other antihypertensives. Mechanistic studies of angiotensin receptor biology will provide further clarity for our findings.

Angiotensin II Type 1 Receptor Antibodies Are Higher in Lupus Nephritis and Vasculitis than Other Glomerulonephritis Patients

Angiotensin II type 1 receptor (AT1R) antibodies are considered non-HLA (human leukocyte antigen) antibodies connected with humoral rejection after kidney transplantation. The role of AT1R antibodies in the pathogenesis of glomerular diseases and systemic vasculitis is unknown. We assessed the level of AT1R antibodies in 136 patients with different types of glomerulonephritis and systemic vasculitis and we observed kidney function and proteinuria, serum albumin and total protein levels for 2 years. The mean levels of AT1R antibodies were the following: 6.00 ± 1.31 U/ml in patients with membranous nephropathy (n = 18), 5.67 ± 1.31 U/ml with focal and segmental glomerulosclerosis (n = 25), 6.26 ± 2.25 U/ml with lupus nephropathy (n = 17), 10.60 ± 6.72 U/ml with IgA nephropathy (n = 14), 6.69 ± 2.52 U/ml with mesangial proliferative (non IgA) glomerulonephritis (n = 6), 6.63 ± 1.38 U/ml with systemic vasculitis (n = 56), including c-ANCA (anti-neutrophil cytoplasmic antibodies) vasculitis: 11.22 ± 10.78 U/ml (n = 40) and p-ANCA vasculitis: 12.65 ± 14.59 U/ml (n = 16). The mean AT1R antibodies level was higher in patients with lupus nephropathy and systemic vasculitis compared to glomerulonephritis groups. An inverse statistically significant correlation between AT1R antibodies and serum albumin (r =  − 0.51) in membranous nephropathy group was also found. Prospective analysis of creatinine levels indicated an increase of creatinine levels during time among patients with higher AT1R antibodies levels in p-ANCA vasculitis. Lupus nephropathy and systemic vasculitis patients may have high levels of AT1R antibodies. AT1R antibodies may be associated with the severity of membranous nephropathy and the course of p-ANCA vasculitis, although influence of concomitant factors is difficult to exclude.

Cardiovascular drug treatment, statins and biopsy-confirmed giant cell arteritis: a population-based case-control study

Objective

To determine whether exposure to cardiovascular medications and statins is associated with increased risk of giant cell arteritis (GCA).

Design

The population-based case–control study comprised a cohort of patients with biopsy-confirmed GCA linked to the Swedish Prescribed Drug Register to identify all exposure to drugs prior to diagnosis of GCA. Ten controls per GCA case, matched for age, sex and residential area, were included. Using corresponding Anatomical Therapeutic Chemical codes, ACE inhibitors, angiotensin II receptor blockers, beta-blocking agents, calcium antagonists, diuretics, statins and cardiac therapy drugs were investigated from July 1, 2005 to the diagnosis/index date. A conditional logistic regression model was fitted adjusted for income, education level and marital status. We repeated the analyses including only new drug users excluding those with any prescription during the year from July 1, 2005 to July 1, 2006.

Results

574 cases (29% men) of diagnosed GCA and 5740 controls (29% men) were included. The mean age at diagnosis is 75 years (SD 8). Of the GCA cases, 71% had at least one dispensation of a cardiovascular drug prior to the index date, compared to 74% of controls. The ORs for the association of target drug exposure with GCA were <1 for most drugs, but close to 1 in the analysis of new users. Statins were consistently associated with lower risk of GCA, OR 0.74 (95% CI 0.61 to 0.90).

Conclusion

Statins may be associated with lower risk of incident biopsy-confirmed GCA. No association was evident for other studied drugs.

Impact of diabetes, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker use, and statin use on presentation and outcomes in patients with giant cell arteritis

AIM

Few, separate, small retrospective studies in giant cell arteritis (GCA) reported that patients: (a) with diabetes mellitus had less positive temporal artery biopsies (TAB); (b) on angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin II receptor blockers (ARB) experienced fewer relapses; and (c) on statins experienced the same frequency of clinical complications and relapses as non-exposed patients. This retrospective chart review study simultaneously investigated the impact of these 3 factors on a cohort of patients followed in 2 large Canadian centers (Hamilton and Toronto, ON).

METHODS

One hundred and thirty-seven patients diagnosed with GCA between 1993 and 2015 were included in the study. Presenting symptoms, TAB results, disease complications and outcomes (relapses, duration of glucocorticoid use) were compared between exposed (diabetes/ACE/ARB/statin) and non-exposed patients, with adjustment for main potential confounding variables.

RESULTS

Temporal artery biopsies was less often positive in patients with pre-existing diabetes (relative risk 0.24; 95% CI: 0.069-0.81). Patients who developed diabetes after diagnosis had a lower relapse-free survival (adjusted hazards ratio [HR] 0.28; 95% CI: 0.095-0.84). Patients taking ARBs prior to diagnosis were more likely to successfully discontinue glucocorticoids without a flare in the following 3 months (adjusted HR 2.46; 95% CI: 1.2-5.3). Clinical complications and relapse rates did not differ between patients on statin therapy or not.

CONCLUSION

Diabetic patients with GCA were less likely to have a positive TAB, and more likely to relapse. ARB therapy prior to diagnosis showed an association with success at discontinuing glucocorticoids. Statin therapy did not alter the clinical presentation or course of GCA.

The Treatment of Giant Cell Arteritis

OPINION STATEMENT

Giant cell arteritis (GCA) is a systemic inflammatory vasculitis affecting medium and large vessels with potentially sight and life-threatening complications. Early diagnosis and prompt treatment are imperative in order to prevent vision loss and progression of the disease. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are inflammatory markers which are elevated in the majority of patients and support the diagnosis of GCA among patients who present with typical symptoms. GCA is confirmed with superficial temporal artery biopsy which demonstrates characteristic pathological findings. Treatment of suspected ophthalmic involvement must be initiated urgently, even when diagnostic studies are pending. High dose corticosteroid therapy is the mainstay of treatment and is administered either intravenously or orally to prevent further vision loss and treat systemic vasculitis. Oral corticosteroid therapy is required for months to years with careful follow-up and periodic laboratory evaluations with ESR and CRP. Corticosteroids are tapered gradually over months and may be associated with complications such as hypertension, diabetes mellitus, osteoporosis, psychosis, peptic ulcer disease, and infection. Supplementation with calcium, vitamin D, bisphosphonate therapy, antimicrobial prophylaxis, and initiation of a proton pump inhibitor or Histamine H2-receptor antagonist should be considered. Recurrence of inflammation is common in GCA and necessitates an escalation of corticosteroid dose. Adjunctive immunomodulatory therapy may be considered in patients experiencing relapsing inflammation despite high doses of corticosteroids or those with corticosteroid-induced complications. Emerging evidence for adjunctive therapy with tocilizumab, methotrexate, aspirin, angiotensin receptor blockers, and statins is encouraging and may lead to a more mainstream role for these therapies among patients with GCA.

MicroRNA markers of inflammation and remodelling in temporal arteries from patients with giant cell arteritis

OBJECTIVES

There is increasing evidence that microRNAs (miRNAs) are deregulated in autoimmune and cardiovascular diseases. The present study aimed to identify if miRNAs are deregulated in giant cell arteritis (GCA), a vasculitis affecting large-sized and medium-sized arteries, and to determine if miRNA levels might allow to discriminate between patients with GCA and those without.

METHODS

58 patients who had temporal artery biopsy (TAB) for suspected GCA were included in the study and divided into three groups: patients with TAB-positive GCA showing a transmural inflammation (n=27), patients with TAB-negative GCA (n=8) and TAB-negative non-GCA patients with a final diagnosis different from GCA (n=23). To identify candidate miRNAs deregulated in GCA, we profiled the expression of 1209 miRNAs in inflamed TABs and normal TABs. Selected miRNAs were then validated by real-time PCRs and in situ hybridisation (ISH).

RESULTS

MiR-146b-5p, -146a, -155, -150, -21 and -299-5p were significantly more expressed in inflamed TABs from patients with GCA. miRNAs were mainly deregulated at the tissue level because peripheral blood mononuclear cells and polymorphonuclear cells from the three groups of patients and age-matched healthy controls had similar levels of miRNAs. ISH showed that miR-21 was mainly expressed by cells in the medial and intimal layers of inflamed TABs. Patients with TAB-negative GCA had a miRNA profile similar to TAB-negative non-GCA patients.

CONCLUSIONS

MiR-146b-5p, -146a, -21, -150, -155, -299-5p are overexpressed in the presence of inflammation in TABs from patients with GCA.

Treatment with angiotensin II receptor blockers is associated with prolonged relapse-free survival, lower relapse rate, and corticosteroid-sparing effect in patients with giant cell arteritis

OBJECTIVE

To determine whether concomitant treatment with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) is associated with changes in the outcome of patients with giant cell arteritis (GCA).

METHODS

A study cohort of 106 patients with biopsy-proven GCA was longitudinally followed up for 7.8 ± 3.3 years. Patients were stratified according to their treatment with ACEI, ARB, or no ACEI/ARB. Time to first relapse, number of flares, time to achieve a stable prednisone dose <10mg/day and <5mg/day with no relapses, time required to completely discontinue prednisone, cumulative dose of prednisone received during the first year, and concentrations of acute-phase reactants at pre-defined time points (baseline, 6, 12, 18, and 24 months) were compared among the 3 groups. Cox proportional hazards models were performed to adjust for potential confounders.

RESULTS

Patients receiving ARB presented a significantly longer relapse-free survival than patients treated with ACEI or patients not receiving ACEI/ARB (p = 0.02). The adjusted hazard ratio for relapses in patients treated with ARB was 0.32 (95% CI: 0.12-0.81, p = 0.017). In addition, patients who received ARB achieved a prednisone maintenance dose <10mg/day faster than all other patients (p = 0.0002). No significant differences were observed among groups in acute-phase reactant levels during follow-up. However, patients not receiving ACEI/ARB had significantly higher C-reactive protein and haptoglobin concentrations than those receiving ACEI or ARB at various time points.

CONCLUSIONS

Addition of ARB to glucocorticoids is associated with lower relapse rate and more prolonged disease-free survival in patients with GCA.

Reduced expression of angiotensin II and angiotensin receptor type 1 and type 2 in resistance arteries from nasal lesions in granulomatosis with polyangiitis (Wegener's granulomatosis)

OBJECTIVES

Angiotensin II (ANGII) is involved in vessel inflammation and is important in the development of cardiovascular disorders such as atherosclerosis. During active disease, patients with granulomatosis with polyangiitis (GPA; Wegener's granulomatosis) have accelerated atherosclerosis and ANGII inhibitors are recommended to these patients to reduce atherosclerosis. We assessed the hypothesis that the expression of ANGII and its receptors in arteries in granulomatous lesions change in GPA.

METHODS

ANGII and angiotensin receptors were quantified in vessels from granulomatous lesions from patients with GPA using immunohistochemistry. Anti- ANGI type 1 (AT1) and type 2 (AT2) antibodies were applied on formalin-fixed and paraffin-embedded biopsies from nasal mucous membranes from eight patients with GPA and eight controls.

RESULTS

ANGII expression was localized to the endothelial cells (ECs) in arteries and sparsely to vascular smooth muscle cells (VSMCs) in nasal biopsies. AT1 receptor (AT1R) staining was intense and located in the VSMCs in the medial layer of the control arteries. AT2 receptor (AT2R) immunostaining was faint and was located only in the ECs. Patients with GPA showed marked down-regulation of positively immunostained ECs for ANGII or AT2R, and a reduced number of AT1R in VSMCs. ANGII, AT1R, and AT2R staining was persistent on infiltrating leucocytes.

CONCLUSIONS

These results suggest down-regulation of the angiotensin system in arteries in granulomatous nasal lesions in GPA. Inhibition of the angiotensin system may prove less efficient in inhibiting the vascular inflammation process in GPA.

Flow cytometric analysis of circulating microparticles in plasma

Microparticles, which include exosomes, micro-vesicles, apoptotic bodies and apoptotic microparticles, are small (0.05 - 3 mum in diameter), membranous vesicles that can contain DNA, RNA, miRNA, intracellular proteins and express extracellular surface markers from the parental cells. They can be secreted from intracellular multivesicular bodies or released from the surface of blebbing membranes. Circulating microparticles are abundant in the plasma of normal individuals and can be derived from circulating blood cells such as platelets, red blood cells and leukocytes as well as from tissue sources, such as endothelial and placental tissues. Elevated levels of microparticles are associated with various diseases such as thrombosis (platelet microparticles), congestive heart failure (endothelial microparticles), breast cancer patients (leukocyte microparticles) and women with preeclampsia (syncytiotrophoblast microparticles). Although microparticles can be detected by microscopy, enzyme-linked immunoassays and functional assays, flow cytometry is the preferred method because of the ability to quantitate (fluorescent bead- or flow rate-based method) and because of polychromatic capabilities. However, standardization of pre-analytical and analytical modus operandi for isolating, enumerating and fluorescent labeling of microparticles remains a challenge. The primary focus of this article is to review the preliminary steps required to optimally study circulating in vivo microparticles which include: 1) centrifugation speed used, 2) quantitation of microparticles before antibody labeling, 3) levels of fluorescence intensity of antibody-labeled microparticles, 4) polychromatic flow cytometric analysis of microparticle sub-populations and 5) use of polyclonal antibodies designed for Western blotting for flow cytometry. These studies determine a roadmap to develop microparticles as biomarkers for a variety of conditions.