Urinary CD4 + T Cells Predict Renal Relapse in ANCA-Associated Vasculitis

SIGNIFICANCE STATEMENT

Early identification of patients at risk of renal flares in ANCA vasculitis is crucial. However, current clinical parameters have limitations in predicting renal relapse accurately. This study investigated the use of urinary CD4 + T lymphocytes as a predictive biomarker for renal flares in ANCA vasculitis. This study, including urine samples from 102 patients, found that the presence of urinary CD4 + T cells was a robust predictor of renal relapse within a 6-month time frame, with a sensitivity of 60% and a specificity of 97.8%. The diagnostic accuracy of urinary CD4 + T cells exceeded that of ANCA titers, proteinuria, and hematuria. Monitoring urinary CD4 + T lymphocytes could help assess the risk of future renal relapse, enabling early preventive measures and tailored treatment strategies.

BACKGROUND

In ANCA-associated vasculitis, there is a lack of biomarkers for predicting renal relapse. Urinary T cells have been shown to differentiate active GN from remission in ANCA-associated vasculitis, but their predictive value for renal flares remains unknown.

METHODS

The PRE-FLARED study was a prospective multicenter biomarker study including 102 individuals with ANCA-associated vasculitis in remission aimed to predict renal relapse by quantifying urinary CD4 + T-cell subsets using flow cytometry at baseline and monitoring clinical outcomes over a 6-month follow-up.

RESULTS

Among the participants, ten experienced renal relapses, two had non-renal flares, and 90 remained in stable remission. The median baseline urinary CD4 + T-cell count was significantly higher in patients who relapsed compared with those in remission. Receiver operating characteristic curve analysis of urinary CD4 + T-cell counts showed an area under the curve value of 0.88 for predicting renal flares, outperforming ANCA titers, hematuria, and proteinuria. Using a cutoff of 490 CD4 + T cells per 100 ml urine, the sensitivity and specificity in identifying patients with future renal flares were 60% and 97.8%, respectively. In a post hoc analysis, combining urinary CD4 + T-cell counts with proteinase-3 ANCA levels suggested improved predictive performance in the PR3 + subgroup. In addition, the number of urinary CD4 + T cells showed a limited correlation with a decline in GFR and an increase in proteinuria over the follow-up period.

CONCLUSIONS

This study concluded that urinary CD4 + T-cell counts could identify patients with ANCA-associated vasculitis at a substantial risk of renal relapse within 6 months. Combining these counts with ANCA levels further improved the prediction of relapse.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

Urinary T Lymphocytes Predict Renal Flares in Patients With Inactive ANCA-associated Glomerulonephritis (PRE-FLARED), NCT04428398 .

UNC93B1 variants underlie TLR7-dependent autoimmunity

UNC93B1 is critical for trafficking and function of nucleic acid-sensing Toll-like receptors (TLRs) TLR3, TLR7, TLR8, and TLR9, which are essential for antiviral immunity. Overactive TLR7 signaling induced by recognition of self-nucleic acids has been implicated in systemic lupus erythematosus (SLE). Here, we report UNC93B1 variants (E92G and R336L) in four patients with early-onset SLE. Patient cells or mouse macrophages carrying the UNC93B1 variants produced high amounts of TNF-α and IL-6 and upon stimulation with TLR7/TLR8 agonist, but not with TLR3 or TLR9 agonists. E92G causes UNC93B1 protein instability and reduced interaction with TLR7, leading to selective TLR7 hyperactivation with constitutive type I IFN signaling. Thus, UNC93B1 regulates TLR subtype-specific mechanisms of ligand recognition. Our findings establish a pivotal role for UNC93B1 in TLR7-dependent autoimmunity and highlight the therapeutic potential of targeting TLR7 in SLE.

Impact of first-line use of caplacizumab on treatment outcomes in immune thrombotic thrombocytopenic purpura

BACKGROUND

The von Willebrand factor-directed nanobody caplacizumab has greatly changed the treatment of immune thrombotic thrombocytopenic purpura (iTTP) in recent years. Data from randomized controlled trials established efficacy and safety.

OBJECTIVES

This study aims to address open questions regarding patient selection, tailoring of therapy duration, obstacles in prescribing caplacizumab in iTTP, effect on adjunct treatment, and outcomes in the real-world setting.

METHODS

We report retrospective, observational cohorts of 113 iTTP episodes treated with caplacizumab and 119 historical control episodes treated without caplacizumab. We aggregated data from the caplacizumab phase II/III trials and real-world data from France, the United Kingdom, Germany, and Austria (846 episodes, 396 treated with caplacizumab, and 450 historical controls).

RESULTS

Caplacizumab was efficacious in iTTP, independent of the timing of therapy initiation, but curtailed the time of active iTTP only when used in the first-line therapy within 72 hours after diagnosis and until at least partial ADAMTS13-activity remission. Aggregated data from multiple study populations showed that caplacizumab use resulted in significant absolute risk reduction of 2.87% for iTTP-related mortality (number needed to treat 35) and a relative risk reduction of 59%.

CONCLUSION

Caplacizumab should be used in first line and until ADAMTS13-remission, lowers iTTP-related mortality and refractoriness, and decreases the number of daily plasma exchange and hospital stay. This trial is registered at www.

CLINICALTRIALS

gov as #NCT04985318.

Urinary T Cells Identify Renal ANCA-Associated Vasculitis and Predict Prognosis: a proof of concept study

Introduction

Necrotizing crescentic glomerulonephritis is a major contributor to morbidity and mortality in Antineutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV). Because therapy relies on immunosuppressive agents with potentially severe adverse effects, a reliable noninvasive biomarker of disease activity is needed to guide treatment.

Methods

We used flow cytometry to quantify T cell subsets in blood and urine samples from 95 patients with AAV and 8 controls to evaluate their biomarker characteristics. These were compared to soluble markers, monocyte chemoattractant protein-1 (MCP-1), soluble CD163 (sCD163), soluble CD25 (sCD25), and complement C5a (C5a), measured using multiplex analysis. Available kidney biopsies (n = 21) were classified according to Berden.

Results

Patients with active renal AAV (rAAV) showed significantly higher urinary cell counts than those in remission, or those with extrarenal manifestation, or healthy controls. Urinary T cells showed robust discrimination of disease activity with superior performance compared to MCP-1 and sCD163. Patients whose kidney biopsies had been classified as "crescentic" according to Berden classification showed higher urinary T cell counts. Discordant regulatory T cells (T_reg) proportions and CD4⁺/CD8⁺ ratio in blood and urine suggested that urinary cells reflect tissue migration rather than mere micro-bleeding. Furthermore, urinary T_reg and T helper cells (T_H17) patterns were associated with clinical response and risk of renal relapse.

Conclusion

Urinary T cells reflect the renal inflammatory milieu in AAV and provide further insights into the pathogenesis of this chronic condition. Their promising potential as noninvasive diagnostic and prognostic biomarkers deserves further exploitation.

Protective alpha1-antitrypsin effects in autoimmune vasculitis are compromised by methionine oxidation

BACKGROUND

Anti-neutrophil cytoplasmic autoantibody (ANCA)-associated vasculitidies (AAV) are life-threatening systemic autoimmune conditions. ANCA directed against proteinase 3 (PR3) or myeloperoxidase (MPO) bind their cell surface-presented antigen, activate neutrophils and cause vasculitis. An imbalance between PR3 and its major inhibitor α1-antitrypsin (AAT) was proposed to underlie PR3- but not MPO-AAV. We measured AAT and PR3 in healthies and AAV patients and studied protective AAT effects pertaining to PR3- and MPO-ANCA.

METHODS

Plasma and blood neutrophils were assessed for PR3 and AAT. Wild-type, mutant, and oxidation-resistant AAT species were produced to characterize AAT-PR3 interactions by flow cytometry, immunoblotting, FRET assays, and surface plasmon resonance measurements. Neutrophil activation was measured using the ferricytochrome C assay and AAT methionine-oxidation by Parallel Reaction Monitoring.

RESULTS

We found significantly increased PR3 and AAT pools in both PR3- and MPO-AAV patients, however, only in PR3-AAV did the PR3 pool correlate with ANCA titer, inflammatory response and disease severity. Mechanistically, AAT prevented PR3 from binding to CD177, thereby reducing neutrophil surface antigen for ligation by PR3-ANCA. Active PR3-AAV patients showed critical methionine-oxidation in plasma AAT that was recapitulated by ANCA-activated neutrophils. The protective PR3-related AAT effects were compromised by methionine-oxidation in the AAT reactive center loop but preserved when two critical methionines were substituted by valine and leucine.

CONCLUSION

Pathogenic differences between PR3- and MPO-AAV are related to AAT regulation of membrane-PR3, attenuating neutrophil activation by PR3- rather than MPO-ANCA. Oxidation-resistant AAT could serve as adjunctive therapy in PR3-AAV.

CSF2-dependent monocyte education in the pathogenesis of ANCA-induced glomerulonephritis

Objectives

Myeloid cell activation by antineutrophil cytoplasmic antibody (ANCA) is pivotal for necrotising vasculitis, including necrotising crescentic glomerulonephritis (NCGN). In contrast to neutrophils, the contribution of classical monocyte (CM) and non-classical monocyte (NCM) remains poorly defined. We tested the hypothesis that CMs contribute to antineutrophil cytoplasmic antibody-associated vasculitis (AAV) and that colony-stimulating factor-2 (CSF2, granulocyte-macrophage colony-stimulating factor (GM-CSF)) is an important monocyte-directed disease modifier.

Methods

Myeloperoxidase (MPO)-immunised MPO^−/− mice were transplanted with haematopoietic cells from wild-type (WT) mice, C–C chemokine receptor 2 (CCR2)^−/− mice to abrogate CM, or transcription factor CCAAT–enhancer-binding protein beta (C/EBPβ)^−/− mice to reduce NCM, respectively. Monocytes were stimulated with CSF2, and CSF2 receptor subunit beta (CSF2rb)-deficient mice were used. Urinary monocytes and CSF2 were quantified and kidney Csf2 expression was analysed. CSF2-blocking antibody was used in the nephrotoxic nephritis (NTN) model.

Results

Compared with WT mice, CCR2^−/− chimeric mice showed reduced circulating CM and were protected from NCGN. C/EBPβ^−/− chimeric mice lacked NCM but developed NCGN similar to WT chimeric mice. Kidney and urinary CSF2 were upregulated in AAV mice. CSF2 increased the ability of ANCA-stimulated monocytes to generate interleukin-1β and to promote T_H17 effector cell polarisation. CSF2rb^−/− chimeric mice harboured reduced numbers of kidney T_H17 cells and were protected from NCGN. CSF2 neutralisation reduced renal damage in the NTN model. Finally, patients with active AAV displayed increased urinary CM numbers, CSF2 levels and expression of GM-CSF in infiltrating renal cells.

Conclusions

CMs but not NCMs are important for inducing kidney damage in AAV. CSF2 is a crucial pathological factor by modulating monocyte proinflammatory functions and thereby T_H17 cell polarisation.

Alternate-day dosing of caplacizumab for immune-mediated thrombotic thrombocytopenic purpura

BACKGROUND

The anti-von Willebrand factor (VWF) nanobody caplacizumab directly prevents the fatal microthrombi formation in immune-mediated thrombotic thrombocytopenic purpura (iTTP), thereby adding a new therapeutic principle to the treatment of this disorder. However, real-world treatment modalities beyond clinical trials remain heterogeneous.

METHODS

Here, we describe the risks and benefits of an alternate-day dosing regimen for caplacizumab by thoroughly analyzing the timing and outcome of this approach in a retrospective cohort of 25 iTTP patients treated with caplacizumab at seven different medical centers in Austria and Germany between 2018 and 2021.

RESULTS

Alternate-day dosing of caplacizumab appeared feasible and led to persisting normal platelet counts in most patients. Five patients experienced iTTP exacerbations or relapses that led to the resumption of daily caplacizumab application. VWF activity was repeatedly measured in 16 of 25 patients and documented sufficient suppression by caplacizumab after 24 and 48 h in line with published pharmacodynamics.

CONCLUSION

Extension of caplacizumab application intervals from daily to alternate-day dosing may be safely considered in selected patients after 3 to 4 weeks of daily treatment. Earlier modifications may be discussed in low-risk patients but require close monitoring for clinical and laboratory features of thrombotic microangiopathy.

THU0321 URINARY T CELLS IDENTIFY ACTIVE RENAL ANCA ASSOCIATED VASCULITIS

Background:

ANCA-associated vasculitis (AAV) causes necrotizing crescentic glomerulonephritis (NCGN) which is a major contributor to morbidity and mortality in AAV. Since therapy relies on cytotoxic agents with potentially severe adverse effects, a reliable non-invasive biomarker of disease activity is needed to determine the right balance between over- and undertreatment. Using the urine space as a window into the local inflammatory milieu of the kidney, quantification of urinary leukocytes using flow cytometry has become an upcoming marker of various other inflammatory kidney diseases. As recent studies have illuminated the emerging role of T regulatory (Treg) and Th17 cells in the pathogenesis of AAV, these could represent a viable non-invasive biomarker more closely displaying the underlying pathogenic processes than metabolites or epiphenomena of inflammation.

Objectives:

To quantify urinary T cells in active renal AAV and asses their biomarker characteristics.

Methods:

Using flow cytometry, T-lymphocytes and their subsets were quantified in peripheral blood and urine samples from patients with active AAV with or without NCGN, in stable remission with previous NCGN and healthy controls. Concentrations of urinary soluble metabolites and cytokines (Monocyte-attracting protein 1 (MCP-1), sCD163, sCD25 and C5a) were measured using Multiplex analysis. Results were verified in a separate validation cohort.

Results:

Patients with renal active AAV (n = 30) showed significantly higher urinary cell counts of total T cells, CD4+, CD8+, Treg and Th17 subsets than disease (n = 21) and healthy controls (n = 8). Patients with active renal AAV also showed a significantly higher percentage of Tregs in urine than in blood. While Tregs allowed a robust discrimination between active renal AAV and disease controls (receiver operator characteristics (ROC): area under the curve (AUC) 0.93, sensitivity 79%, specificity 95%) quantification of all T cells proved to be slightly more accurate (ROC: AUC 0.95, sensitivity 92%, specificity 95%). Soluble markers showed a slightly inferior discrimination (MCP-1 ROC: AUC 0.90, sensitivity 60%, specificity 100%, sCD163 ROC: AUC 0.92, sensitivity 96%, specificity 85%) while sCD25 and C5a were far less accurate.

Conclusion:

Urinary T cells are significantly elevated in active renal AAV and the increased frequency of Tregs in urine suggests active migration into inflamed glomeruli and thereby the urine rather than mere bleeding of ruptured capillaries. These cells show great potential for a non-invasive biomarker close to the local inflammatory milieu. Particularly the total count of urinary T cells showed slightly superior biomarker characteristics than previously established soluble markers. Further studies are needed to confirm these results and show potential prognostic value of these cellular markers.

Disclosure of Interests:

None declared

A patient with chronic kidney disease, primary biliary cirrhosis and metabolic acidosis

Autoimmune disorders such as rheumatoid arthritis or Sjögren's syndrome can be associated with impaired renal acid excretion. Only few cases of patients with primary biliary cirrhosis (PBC) and distal renal tubular acidosis (dRTA) have been described. Here, we present the case of a 60-year-old woman with PBC and dRTA. Her kidney biopsy showed an absence of markers of acid-secretory Type A intercalated cells (A-ICs) and expression of aquaporin-2, a marker of principal cells, in all cells lining the collecting duct. Moreover, the serum of the patient contained antibodies directed against a subset of cells of the collecting duct. Thus, PBC-related autoantibodies may target acid-secretory A-ICs and thereby impair urinary acidification.

Kaliopenic nephropathy revisited

In the ‘older’ literature, a definitive renal pathology was described in patients with long-standing hypokalaemia and depletion of the body's potassium reserves. The topic is relevant because possibly a quite cheaply reversible element in the course of chronic kidney disease progression could be addressed. Earlier, pathologists drew attention to vacuolar changes in renal tubular epithelium accompanied by inflammatory interstitial changes in patients with potassium losses. The diagnostic term ‘kaliopenic nephropathy’ was coined to describe such patients. Kaliopenic nephropathy now receives less emphasis than in earlier times. However, with eating disorders, laxative abuse and other potential causes, we suggest that the syndrome should be resurrected.

A cardiorenal-pulmonary-cutaneous-muscle syndrome

Anti-synthetase syndrome is a relatively recently described auto-immune disease characterized by auto-antibodies to enzymes that acetylate transfer RNA (tRNA). Interstitial pulmonary disease and inflammatory myopathy are regular findings. Our patient also exhibited a lupus-like glomerulonephritis. An important clue was the presence of ‘mechanics’ hands. Nephrologists need to be aware of this syndrome.

Structural and magnetic modulations in CaCu(x)Mn(7 - x)O(12)

Low temperature atomic position modulations and magnetic moment modulations are reported for CaCu(x)Mn(7 - x)O(12) (x = 0.0, 0.1 and 0.23) using neutron powder diffraction. Both modulations are described with propagation vectors (0, 0, q) parallel to the c-axis in the hexagonal setting. The present neutron diffraction studies confirm the quantitative model describing the atomic position modulations in CaCu(x)Mn(7 - x)O(12) (x = 0.0 and 0.1) as derived from synchrotron based powder x-ray diffraction studies (Sławiński et al 2009 Acta Crystallogr. B 65 535). Neutron diffraction studies confirm the relation between the atomic position modulation length L(p) and the magnetic modulation length L(m) = 2L(p) between 50 K and the Néel temperature T(N). CaCu(x)Mn(7 - x)O(12) (x = 0.1 and 0.23) shows a magnetic phase transition near 50 K associated with considerable changes of the magnetic modulation length and the magnetic coherence length, similar to that observed in the parent CaMn(7)O(12).

Modulation of atomic positions in CaCuxMn(7-x)O12 (x < or = 0.1)

The modulation of atomic positions in CaCu(x)Mn(7-x)O12 (x = 0 and 0.1) was studied using synchrotron radiation powder diffraction below 250 and 220 K, respectively. The copper-rich member CaCu(x)Mn(7-x)O12 (x = 0.23) does not show any modulation of the atomic positions at temperatures as low as 10 K. Using low-temperature neutron powder diffraction the modulation of the magnetic moments of Mn ions in CaCu(x)Mn(7-x)O12 (x = 0, 0.1 and 0.23) has been investigated. Long-range modulated magnetic ordering in CaCu(x)Mn(7-x)O12 (x = 0, 0.1 and 0.23) is observed below 90.4, 89.2 and 78.1 K. (0,0,q(p)) and (0,0,q(m)) are the propagation vectors describing the modulations of the atomic positions and the magnetic moments. For CaCu(x)Mn(7-x)O12 (x = 0 and 0.1) the magnetic modulation and atomic modulation lengths are related by a factor of 2 satisfying the relation (1-q(p)) = 2(1-q(m)).

The hydride anion in an extended transition metal oxide array: LaSrCoO3H0.7

We present the synthesis and structural characterization of a transition metal oxide hydride, LaSrCoO3H0.7, which adopts an unprecedented structure in which oxide chains are bridged by hydride anions to form a two-dimensional extended network. The metal centers are strongly coupled by their bonding with both oxide and hydride ligands to produce magnetic ordering at temperatures up to at least 350 kelvin. The synthetic route is sufficiently general to allow the prediction of a new class of transition metal--containing electronic and magnetic materials.

Amelioration of angiotensin II-induced cardiac injury by a 3-hydroxy-3-methylglutaryl coenzyme a reductase inhibitor

BACKGROUND

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have effects that extend beyond cholesterol reduction. We used an angiotensin (Ang) II-dependent model to test the hypothesis that cerivastatin ameliorates cardiac injury.

METHODS AND RESULTS

We treated rats transgenic for human renin and angiotensinogen (dTGR) chronically from weeks 4 to 7 with cerivastatin (0.5 mg/kg by gavage). We used immunohistochemistry, electrophoretic mobility shift assays, and reverse transcription-polymerase chain reaction techniques. Compared with control dTGR, dTGR treated with cerivastatin had reduced mortality, blood pressure, cardiac hypertrophy, macrophage infiltration, and collagen I, laminin, and fibronectin deposition. Basic fibroblast growth factor mRNA and protein expression were markedly reduced, as was interleukin-6 expression. The transcription factors NF-kappaB and AP-1 were substantially less activated, although plasma cholesterol was not decreased.

CONCLUSIONS

These results suggest that statins ameliorate Ang II-induced hypertension, cardiac hypertrophy, fibrosis, and remodeling independently of cholesterol reduction. Although the clinical significance remains uncertain, the results suggest that statins interfere with Ang II-induced signaling and transcription factor activation, thereby ameliorating end-organ damage.

Mineralocorticoid receptor affects AP-1 and nuclear factor-kappab activation in angiotensin II-induced cardiac injury

Aldosterone is implicated in cardiac hypertrophy and fibrosis. We tested the role of the mineralocorticoid receptor in a model of angiotensin II-induced cardiac injury. We administered spironolactone (SPIRO; 20 mg. kg(-1). d(-1)), valsartan (VAL; 10 mg. kg(-1). d(-1)), or vehicle to rats double transgenic for the human renin and angiotensinogen genes (dTGR). We investigated basic fibroblast growth factor (bFGF), platelet-derived growth factor, transforming growth factor-beta(1), and the transcription factors AP-1 and nuclear factor (NF)-kappaB. We used immunohistochemistry, electrophoretic mobility shift assays, and TaqMan RT-PCR. Untreated dTGR developed hypertension, cardiac hypertrophy, vasculopathy, and fibrosis with a 50% mortality rates at 7 weeks. SPIRO and VAL prevented death and reversed cardiac hypertrophy, while only VAL normalized blood pressure. Both drugs prevented vasculopathy. bFGF was markedly upregulated in dTGR, whereas platelet-derived growth factor-B and transforming growth factor-beta(1) were little changed. VAL and SPIRO suppressed this upregulation. Both AP-1 and NF-kappaB were activated in dTGR compared with controls. VAL and SPIRO reduced both transcription factors and reduced bFGF, collagen I, fibronectin, and laminin in the interstitium. These findings show that aldosterone promotes hypertrophy, cardiac remodeling, and fibrosis, independent of blood pressure. The effects involve AP-1, NF-kappaB, and bFGF. Mineralocorticoid receptor blockade downregulates these effectors and reduces angiotensin II-induced cardiac damage.

Dexamethasone Inhibits Nf-κB, P22phox, and Protects Against Angiotensin Ii-Induced Renal Damage

P167

We recently reported that NF-κB activation promotes inflammation in rats harboring both human renin and angiotensinogen genes (dTGR). We now tested the hypothesis that dexamethasone (DEX) inhibits NF-κB and ameliorates renal and cardiac end-organ damage. The dTGR feature moderate hypertension, severe renal, and cardiac damage, as well as over 50% mortality at 7 weeks. Immunohistochemical analysis shows increased infiltration of monocytes and T-cells. Electrophoretic mobility shift assay showed increased NF-κB DNA binding activity in heart and kidney of dTGR. One-week treatment with DEX (1 mg/kg/d i.p.) initially increased blood pressure at week 5, compared to dTGR (191±2 vs.152±6 mm Hg, p<0.01), whereas blood pressure was not different at week 7 (193±15 vs. 182±8 mm Hg, p=0.8). However, DEX reduced 24 h albuminuria by 85 % (2.7±0.5 vs. 18.0±3.4 mg/d, p<0.001) and prevented mortality completely. Vasculopathy was ameliorated in kidney and heart and perivascular fibrosis was reduced. DEX inhibited NF-κB DNA-binding activity and also the NF-κB-regulated adhesion molecule ICAM-1. We also studied localization of NADPH subunit p22phox. Immunostaining of p22phox was detected in the endothelium and also colocalized with monocytes. DEX reduced both infiltration of cells and p22phox expression. Thus, these results demonstrate that DEX suppresses NF-κB binding activity, p22phox expression of infiltrated cells, inflammation, and protects against angiotensin II-induced end-organ damage, all without blood pressure reduction.

Cerivastatin prevents angiotensin II-induced renal injury independent of blood pressure- and cholesterol-lowering effects

BACKGROUND

Statins are effective in prevention of end-organ damage; however, the benefits cannot be fully explained on the basis of cholesterol reduction. We used an angiotensin II (Ang II)-dependent model to test the hypothesis that cerivastatin prevents leukocyte adhesion and infiltration, induction of inducible nitric oxide synthase (iNOS), and ameliorates end-organ damage.

METHODS

We analyzed intracellular targets, such as mitogen-activated protein kinase and transcription factor (nuclear factor-kappaB and activator protein-1) activation. We used immunohistochemistry, immunocytochemistry, electrophoretic mobility shift assays, and enzyme-linked immunosorbent assay techniques. We treated rats transgenic for human renin and angiotensinogen (dTGR) chronically from week 4 to 7 with cerivastatin (0.5 mg/kg by gavage).

RESULTS

Untreated dTGR developed hypertension, cardiac hypertrophy, and renal damage, with a 100-fold increased albuminuria and focal cortical necrosis. dTGR mortality at the age of seven weeks was 45%. Immunohistochemistry showed increased iNOS expression in the endothelium and media of small vessels, infiltrating cells, afferent arterioles, and glomeruli of dTGR, which was greater in cortex than medulla. Phosphorylated extracellular signal regulated kinase (p-ERK) was increased in dTGR; nuclear factor-kappaB and activator protein-1 were both activated. Cerivastatin decreased systolic blood pressure compared with untreated dTGR (147 +/- 14 vs. 201 +/- 6 mm Hg, P < 0.001). Albuminuria was reduced by 60% (P = 0.001), and creatinine was lowered (0.45 +/- 0.01 vs. 0.68 +/- 0.05 mg/dL, P = 0. 003); however, cholesterol was not reduced. Intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression was diminished, while neutrophil and monocyte infiltration in the kidney was markedly reduced. ERK phosphorylation and transcription factor activation were reduced. In addition, in vitro incubation of vascular smooth muscle cells with cerivastatin (0.5 micromol/L) almost completely prevented the Ang II-induced ERK phosphorylation.

CONCLUSION

Cerivastatin reduced inflammation, cell proliferation, and iNOS induction, which led to a reduction in cellular damage. Our findings suggest that 3-hydroxy-3-methylglutaryl coenzyme (HMG-CoA) reductase inhibition ameliorates Ang II-induced end-organ damage. We suggest that these effects were independent of cholesterol.

Cardiac Protective Effect of Aldosterone Blockade Is Mediated Through Ap-1 and Nf-κB Suppression in Angiotensin Ii-Induced Cardiac Damage

77

Aldosterone is a multifunctional mineralocorticoid affecting homeostasis of water and electrolytes, sympathetic activity, and tissue fibrosis. Aldosterone synthesis is induced by activation of the renin-angiotensin system. We tested whether or not the inhibition of aldosterone signaling can prevent fibrotic tissue remodeling in vivo. In a transgenic rat model overexpressing the human renin and angiotensinogen gens (dTGR), we investigated the effect of spironolactone (SPIRO 20 mg/kg/d) and the AT1 receptor blocker valsartan (VAL; 10 mg/kg/d) on growth factors and transcription factors leading chronic inflammation and tissue fibrosis. Untreated dTGR develop severe hypertension, cardiac hypertrophy, vasculopathy, and perivascular fibrosis. The hearts also show chronic inflammation and the animals have a 50% mortality at 7 weeks. VAL completely reversed these pathological features. SPIRO and VAL both prevented mortality, while only VAL normalized systolic blood pressure (VAL 121±9, SPIRO 161±11, dTGR 182±8, SD 109±2 mm Hg). Both reduced cardiac hypertrophy (SPIRO 4.2±0.1, VAL 3.6±0.1, dTGR 5.7±0.2, SD 3.6±0.1 mg/g) and reduced vasculopathy. Quantitative bFGF RT-PCR showed a complete mRNA reduction in the left ventricle in both treatment groups (SPIRO 11±4, VAL 5±1 dTGR 43±4, SD 4±1 arbitrary units). In contrast, RT-PCR of TGF beta and PDGF showed no upregulation in dTGR compared to non-transgenic hearts. Gel shift assay of the heart demonstrated a suppression of AP-1 and NF-κB DNA binding activity after SPIRO and VAL treatment. Immunohistology revealed reduced bFGF expression and less collagen I, fibronectin, and laminin in the interstitium of SPIRO and VAL-treated rats. These findings show that aldosterone promotes hypertrophy, cardiac remodeling, and fibrosis. In dTGR hearts this effect is at least partly mediated through the transcription factors AP-1 and NF-κB as well as bFGF. Blocking the aldosterone receptor downregulates these effector molecules and reduces angiotensin II-induced cardiac damage.

Spironolactone Ameliorates Angiotensin Ii-Induced Renal Damage Via the Inhibition of Ap-1 and Nf-κB

P168

Recently, clinical trials have demonstrated the efficacy of spironolactone (SPIRO) in men. Nevertheless the molecular mechanism of action not completely understood. Locally generated angiotensin II (ANG II) stimulates aldosterone. Therefore, we have tested the hypothesis that SPIRO ameliorates ANG II-induced renal damage. Furthermore, we investigated the effect of SPIRO on the transcription factors AP-1 and NF-κB. We treated transgenic rats overexpressing the human renin and angiotensinogen genes (dTGR) from week 5 to 7 with SPIRO (20 mg/kg/d). Plasma aldosterone was significantly increased in dTGR vs. SPIRO treated and non-transgenic (SD) rats (p<0.05). Untreated dTGR showed high systolic blood pressure (182±8 mm Hg), severe renal damage with 150-fold increased albuminuria, vasculopathy and perivascular and interstitial fibrosis. Chronic SPIRO treatment reduced mortality and vasculopathy completely, despite blood pressure levels of 161±11. 24-hour albuminuria was reduced from 59±15 in dTGR to 3.5±2 mg/d; p<0.01). Electrophoretic mobility gel shift analysis demonstrated a reduction of renal AP-1 and NF-κB DNA binding activity after SPIRO treatment. Immunohistological analysis showed that SPIRO also prevented the expression of AP-1 and/or NF-kB regulated matrix molecules fibronectin and laminin. The reno-protective effect of SPIRO was accompanied with a reduction of monocyte/macrophage infiltration. These findings show that blockade of aldosterone signaling ameliorates ANG II-induced renal damage. SPIRO action was at least partially mediated via AP-1 and NF-κB.

Amelioration of Angiotensin Ii-Induced Cardiac Injury by Hmg-Coa Reductase Inhibition

32

HMG-CoA reductase inhibitors have effects that extend beyond cholesterol reduction. We used an angiotensin (Ang) II-dependent model to test the hypothesis that cerivastatin ameliorates cardiac injury. We treated rats transgenic for human renin and angiotensinogen (dTGR) chronically from week 4 to 7 with cerivastatin (0.5 mg/kg/d by gavage). We used immunohistochemistry, electrophoretic mobility shift assays, and RT-PCR techniques. Compared to control dTGR, dTGR treated with cerivastatin had reduced mortality, blood pressure, cardiac hypertrophy, macrophage infiltration, and collagen I and IV deposition. Total plasma cholesterol was not different between the groups. Immunohistochemical analysis showed increased expression of basic fibroblast growth factor (b-FGF), IL-6, and the NF-κB subunit p65 in the media of dTGR, which was markedly reduced by cerivastatin. b-FGF mRNA in the left ventricle was also significantly reduced. The transcription factors NF-κB and AP-1 were substantially less activated in the left ventricle. These results suggest that statins ameliorate Ang II-induced hypertension, cardiac hypertrophy, and remodeling, independent of cholesterol reduction. They suggest that statins interfere with Ang II-induced signaling and transcription factor activation, thereby ameliorating end-organ damage.

Cyclosporin A protects against angiotensin II-induced end-organ damage in double transgenic rats harboring human renin and angiotensinogen genes

Leukocyte infiltration and adhesion molecule activation play a central role in the pathogenesis of angiotensin II (Ang II)-induced end-organ damage in double transgenic rats (dTGR) harboring human renin and angiotensinogen genes. We tested the hypothesis that the immunosuppressive agent cyclosporine (CsA) protects against the Ang II-induced myocardial and renal damage in dTGR. Furthermore, we investigated the influence of CsA on interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) expression and the DNA binding activity of transcription factor necrosis factor-kappaB (NF-kappaB). The 4-week-old rats were divided into 4 groups: (1) control dTGR (n=20), (2) dTGR plus CsA (5 mg/kg SC for 3 weeks, n=15), (3) normotensive Sprague-Dawley (SD) rats (n=10), and (4) SD rats plus CsA (n=8). In dTGR, CsA completely prevented cardiovascular death (0 of 15 versus 9 of 20), decreased 24-hour albuminuria by 90% and systolic blood pressure by 35 mm Hg, and protected against the development of cardiac hypertrophy. Whole blood CsA concentrations 24 hours after the last drug treatment were 850+/-15 ng/mL. Semiquantitative ED-1 and Ki-67 (a nuclear cell proliferation-associated antigen) scoring showed that CsA prevented perivascular monocyte/macrophage infiltration and prevented cell proliferation in the kidneys and hearts of dTGR, respectively. The beneficial effects of CsA were, at least in part, mediated by the suppression of IL-6 and iNOS expression. Electrophoretic mobility shift assay revealed that CsA regulated inflammatory response in part through the NF-kappaB transcriptional pathway. In contrast to dTGR, CsA increased blood pressure in normotensive SD rats by 10 mm Hg and had no effect on cardiac mass or 24-hour urinary albumin excretion. Perivascular monocyte/macrophage infiltration, IL-6, and iNOS expression or cell proliferation were not affected by CsA in SD rats. Our findings indicate that CsA protects against Ang II-induced end-organ damage and underscore the central role of vascular inflammatory response in the pathogenesis of myocardial and renal damage in dTGR. The beneficial effects of CsA in the kidney and heart are mediated, at least in part, by suppression of IL-6 and iNOS expression via NF-kappaB transcriptional pathway.