Immune response of heterologous versus homologous prime-boost regimens with adenoviral vectored and mRNA COVID-19 vaccines in immunocompromised patients

Due to rare but major adverse reactions to the AstraZeneca adenoviral ChAdOx1-S-nCoV-19 vaccine (ChAd), German health authorities recommended adults under 60 who received one dose of ChAd, to receive a second dose of the BioNTech mRNA BNT162b2 vaccine (BNT) as a booster. Studies in the general population suggest an enhanced efficacy of the heterologous (ChAd-BNT) compared to the homologous (BNT-BNT) vaccination regimen. However, an analysis of the efficacy in patient populations with a high risk of severe COVID-19 due to acquired immunodeficiency is still missing. We therefore compared both vaccination regimens in healthy controls, patients with gynecological tumors after chemotherapy, patients on dialysis and patients with rheumatic diseases concerning the humoral and cellular immune response. The humoral and cellular immune response differed substantially in healthy controls compared to patients with acquired immunodeficiency. Overall, the most significant differences between the two immunization regimens were found in neutralizing antibodies. These were always higher after a heterologous immunization. Healthy controls responded well to both vaccination regimens. However, the formation of neutralizing antibodies was more pronounced after a heterologous immunization. Dialysis patients, on the other hand, only developed an adequate humoral and particularly cellular immune response after a heterologous immunization. Tumor and rheumatic patients also - to a weaker extent compared to dialysis patients - benefited from a heterologous immunization. In conclusion, the heterologous COVID-19 vaccination regimens (ChAd-BNT) seem to have an advantage over the homologous vaccination regimens, especially in immunocompromised patients such as patients with end-stage kidney disease treated with hemodialysis.

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.

Impact of hypertension on long-term humoral and cellular response to SARS-CoV-2 infection

It was shown that hypertension delays SARS CoV-2 viral clearance and exacerbates airway hyperinflammation in the respiratory tract. However, it is unknown whether hypertension determines the long-term cellular and humoral response to SARS Cov2. Health care workers (HCWs) after an outbreak of SARS Cov-2 infections were analyzed. Infected HCWs were not vaccinated before blood collection. 5-14 months (median 7 months) after detection of SARS CoV-2 infection, blood was taken to analyze humoral response (S1 IgG and SARS CoV-2 neutralizing antibodies) and cellular (T cell responses to SARS-CoV-2 with Lymphocyte Transformation Test). To identify clinical factors that determine the immune response, a multivariate regression analysis was done considering age, BMI, sex, diabetes, hypertension, smoking, COPD, asthma and time between PCR positivity and blood collection as confounding factors. Infected hypertensive HCWs more often needed to be hospitalized than non-hypertensive HCWs, but were less likely to develop anosmia and myalgia. The long-term humoral and cellular immune response was significantly strengthened in hypertensive versus normotensive infected HCWs. Multivariate regression analysis revealed that hypertension was independently associated with the humoral response to SARS CoV-2 infection. Multivariate regression analysis using same confounding factors for the humoral response showed a clear trend for an association with the cellular response to SARS CoV-2 infection as well. In conclusion, SARS CoV-2 infection strengthened immune response to SARS CoV-2 infection in hypertensive HCWs independent of other risk factors.

Head-to-head comparison of two SGLT-2 inhibitors on AKI outcomes in a rat ischemia-reperfusion model

The CREDENCE trial testing canagliflozin and the EMPA-REG OUTCOME trial testing empagliflozin suggest different effects on acute kidney injury (AKI). AKI diagnosis was mainly made based on changes of serum creatinine (sCr) although this also reflect mode of action of SGLT-2 inhibitors. We analyzed both compounds in a rat AKI model. The renal ischemia-reperfusion injury (I/R) model was used. Four groups were analyzed: sham, I/R+placebo, I/R+canagliflozin (30 mg/kg/day), I/R+ empagliflozin (10 mg/kg/day). Glucose excretion was comparable in both treatment groups indicating comparable SGLT-2 inhibition. Comparing GFR surrogate markers after I/R (sCr and blood urea nitrogen (BUN)), sCr peaked 24 h after I/R, BUN after 48 h, respectively, in the placebo treated I/R group. At all investigated time points after I/R sCr and BUN was higher in the I/R + canagliflozin group as compared to placebo treated rats, whereas the empagliflozin group did not differ from the placebo group. I/R led to tubular dilatation and necrosis. Empagliflozin was able to reduce that finding whereas canagliflozin had no effect. Treatment with empagliflozin also resulted in a significant reduction in an improved inflammatory score (p = 0.006). Renal expression of kidney injury molecule-1 (KIM-1) increased after I/R and empagliflozin but not canagliflozin significantly alleviated KIM-1 expression. I/R reduced urinary miR-26a excretion. Empagliflozin but not canagliflozin was able to restore normal levels of urinary miR-26a. This study in an AKI model confirmed safety data in the EMPA-REG OUTCOME trial suggesting that empagliflozin might reduce AKI risk. The empagliflozin effects on KIM-1 and miR-26a might indicate beneficial regulation of inflammation. These data should stimulate clinical studies with AKI risk as primary endpoint.

T-cell proliferation assay for the detection of SARS-CoV-2-specific T-cells

Both infection with and vaccination against SARS-CoV-2 trigger a complex B-cell and T-cell response. Methods for the analysis of the B-cell response are now well established. However, reliable methods for measuring the T-cell response are less well established and their usefulness in clinical settings still needs to be proven. Here, we have developed and validated a T-cell proliferation assay based on 3H thymidine incorporation. The assay is using SARS-CoV-2 derived peptide pools that cover the spike (S), the nucleocapsid (N) and the membrane (M) protein for stimulation. We have compared this novel SARS-CoV-2 lymphocyte transformation test (SARS-CoV-2 LTT) to an established ELISA assay detecting Immunoglobulin G (IgG) antibodies to the S1 subunit of the SARS-CoV-2 spike protein. The study was carried out using blood samples from both vaccinated and infected health care workers as well as from a non-infected control group. Our novel SARS-CoV-2 LTT shows excellent discrimination of infected and/or vaccinated individuals versus unexposed controls, with the ROC analysis showing an area under the curve (AUC) of > 0.95. No false positives were recorded as all unexposed controls had a negative LTT result. When using peptide pools not only representing the S protein (found in all currently approved vaccines) but also the N and M proteins (not contained in the vast majority of vaccines), the novel SARS-CoV-2 LTT can also discriminate T-cell responses resulting from vaccination against those induced by infection.

Urinary Neutrophil Gelatinase-Associated Lipocalin/Hepcidin-25 Ratio for Early Identification of Patients at Risk for Renal Replacement Therapy After Cardiac Surgery: A Substudy of the BICARBONATE Trial

BACKGROUND

Acute kidney injury requiring renal replacement therapy (AKI-RRT) is strongly associated with mortality after cardiac surgery; however, options for early identification of patients at high risk for AKI-RRT are extremely limited. Early after cardiac surgery, the predictive ability for AKI-RRT even of one of the most extensively evaluated novel urinary biomarkers, neutrophil gelatinase-associated lipocalin (NGAL), appears to be only moderate. We aimed to determine whether the NGAL/hepcidin-25 ratio (urinary concentrations of NGAL divided by that of hepcidin-25) early after surgery may compare favorably to NGAL for identification of high-risk patients after cardiac surgery.

METHODS

This is a prospective substudy of the BICARBONATE trial, a multicenter parallel-randomized controlled trial comparing perioperative bicarbonate infusion for AKI prevention to usual patient care. At a tertiary referral center, 198 patients at increased kidney risk undergoing cardiac surgery with cardiopulmonary bypass were included into the present study. The primary outcome measure was defined as AKI-RRT. Secondary outcomes were in-hospital mortality and long-term mortality. We compared area under the curve of the receiver operating characteristic (AUC-ROC) of urinary NGAL with that of the urinary NGAL/hepcidin-25 ratio within 60 minutes after end of surgery. We compared adjusted AUC and performed cross-validated reclassification statistics of the (logarithmic) urinary NGAL/hepcidin-25 ratio adjusted to Cleveland risk score/EuroScore, cross-clamp time, age, volume of packed red blood cells, and (logarithmic) urinary NGAL concentration. The association of the NGAL/hepcidin-25 ratio with long-term patient survival was assessed using Cox proportional hazard regression analysis adjusting for EuroScore, aortic cross-clamp time, packed red blood cells and urinary NGAL.

RESULTS

Patients with AKI-RRT (n = 13) had 13.7-times higher NGAL and 3.3-times lower hepcidin-25 concentrations resulting in 46.9-times higher NGAL/hepcidin-25 ratio early after surgery compared to patients without AKI-RRT. The NGAL/hepcidin-25 ratio had higher AUC-ROC compared with NGAL for risk of AKI-RRT and in-hospital mortality (unadjusted AUC-ROC difference 0.087, 95% confidence interval [CI], 0.036-0.138, P < .001; 0.082, 95% CI, 0.018-0.146, P = .012). For AKI-RRT, the NGAL/hepcidin-25 ratio increased adjusted category-free net reclassification improvement (cfNRI; 0.952, 95% CI, 0.437-1.468; P < .001) and integrated discrimination improvement (IDI; 0.040, 95% CI, 0.008-0.073; P = .016) but not AUC difference. For in-hospital mortality, the ratio improved AUC of the reference model (AUC difference 0.056, 95% CI, 0.003-0.108; P = .037) and cfNRI but not IDI. The urinary NGAL/hepcidin-25 ratio remained significantly associated with long-term mortality after adjusting for the model covariates.

CONCLUSIONS

The urinary NGAL/hepcidin-25 ratio appears to early identify high-risk patients and outperform NGAL after cardiac surgery. Confirmation of our findings in other cardiac surgery centers is now needed.

Urinary biomarkers to predict severe fluid overload after cardiac surgery: a pilot study

Aim: To assess the predictive ability of urinary and plasma biomarkers and clinical routine parameters for subsequent severe fluid overload. Patients & methods: In a pilot study, we studied 100 adult patients after cardiac surgery. On intensive care unit admission, we measured biomarkers in urine (midkine, IL-6, neutrophil gelatinase-associated lipocalin [NGAL], hepcidin-25) and plasma (creatinine, urea, B-type natriuretic peptide, lactate, C-reactive protein, leukocytes, IL-6, NGAL, hepcidin-25) to predict postoperative severe fluid overload. Results: Urinary midkine, IL-6, NGAL and hepcidin-25 (all AUCs ≥0.79) predicted postoperative severe fluid overload (n = 5 patients). Urinary NGAL/hepcidin-25 ratio (AUC 0.867) predicted postoperative severe fluid overload after adjustment to EuroScore and need for norepinephrine on surgery day (odds ratio: 2.4). Conclusion: Urinary biomarkers on intensive care unit admission might be helpful to predict subsequent severe fluid overload after cardiac surgery.

Predictive Value of Plasma NGAL:Hepcidin-25 for Major Adverse Kidney Events After Cardiac Surgery with Cardiopulmonary Bypass: A Pilot Study

Background

Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin-25 are involved in catalytic iron-related kidney injury after cardiac surgery with cardiopulmonary bypass. We explored the predictive value of plasma NGAL, plasma hepcidin-25, and the plasma NGAL:hepcidin-25 ratio for major adverse kidney events (MAKE) after cardiac surgery.

Methods

We compared the predictive value of plasma NGAL, hepcidin-25, and plasma NGAL:hepcidin-25 with that of serum creatinine (Cr) and urinary output and protein for primary-endpoint MAKE (acute kidney injury [AKI] stages 2 and 3, persistent AKI >48 hours, acute dialysis, and in-hospital mortality) and secondary-endpoint AKI in 100 cardiac surgery patients at intensive care unit (ICU) admission. We performed ROC curve, logistic regression, and reclassification analyses.

Results

At ICU admission, plasma NGAL, plasma NGAL:hepcidin-25, plasma interleukin-6, and Cr predicted MAKE (area under the ROC curve [AUC]: 0.77, 0.79, 0.74, and 0.74, respectively) and AKI (0.73, 0.89, 0.70, and 0.69). For AKI prediction, plasma NGAL:hepcidin-25 had a higher discriminatory power than Cr (AUC difference 0.26 [95% CI 0.00-0.53]). Urinary output and protein, plasma lactate, C-reactive protein, creatine kinase myocardial band, and brain natriuretic peptide did not predict MAKE or AKI (AUC <0.70). Only plasma NGAL:hepcidin-25 correctly reclassified patients according to their MAKE and AKI status (category-free net reclassification improvement: 0.82 [95% CI 0.12-1.52], 1.03 [0.29-1.77]). After adjustment to the Cleveland risk score, plasma NGAL:hepcidin-25 ≥0.9 independently predicted MAKE (adjusted odds ratio 16.34 [95% CI 1.77-150.49], P=0.014).

Conclusions

Plasma NGAL:hepcidin-25 is a promising marker for predicting postoperative MAKE.

MO1049PROGRESSION OF CHRONIC KIDNEY DISEASE AND LONG-TERM MORTALITY IN PATIENTS HOSPITALIZED WITH TRICUSPID REGURGITATION

Background and Aims

Uremic toxins negatively affect the cardiovascular system resulting in significant morbidity and mortality. However, independent risk factors for chronic kidney disease (CKD) and that of worsening CKD have not been studied in patients with tricuspid regurgitation (TR), yet. Accordingly, in this study, we aimed to assess independent risk factors for the development of progressive CKD in patients with TR. Also, the impact of progressive CKD on long-term mortality was evaluated.

Method

This retrospective, single-center study comprised 444 consecutive patients with TR who were hospitalized between January 2010 and June 2017. We excluded patients with CKD stage 5. Demographic data, comorbidities, type of admission, medication, echocardiographic and laboratory parameters, and survival status were obtained from patient medical record from index hospital admission through discharge. For at least three years, serum creatinine concentrations and survival status were collected from outpatient medical record. We identified independent risk factors for CKD progression. Also, we assessed the impact of CKD progression and other variables on 3-year mortality using multivariable logistic regression analysis. For analysis of 3-year mortality, we grouped patients according to different combinations of their TR grade and presence or absence of CKD progression.

Results

Stage of CKD at hospital admission (odds ratio 0.34 [95% confidence interval 0.24-0.50], p &lt; 0.001), baseline hemoglobin concentration (OR 0.72 [95% CI 0.57-0.92], p=0.006) and presence of diabetes type 2 (OR 1.81 [95% CI 1.08-3.03], p=0.024) were identified as independent risk factors for CKD progression. Progression of CKD during follow-up (OR 2.16 [95% CI 1.31-3.57], p=0.003), grade of TR and mitral regurgitation during index hospital stay and hemoglobin concentration at baseline were independent risk factors for 3-year mortality. Combination of TR grade and status of CKD progression showed a stepwise pattern for 3-year mortality (Figure 1). Patients with TR 1 and CKD progression had a similar 3-year mortality as patients with TR 2 or 3 but no CKD progression. In patients with TR 1, risk for 3-year mortality doubled if CKD progression occurred (OR 2.49 [95% CI 1.38-4.47], p=0.002).

Conclusion

Although retrospective studies cannot imply causal relationship, based on study findings, kidney follow-up especially in patients with mild TR may be advisable. If CKD progression can be prevented in patients with TR and if such kidney protection may reduce long-term mortality may be objective of future studies.

FC 051PREDICTIVE VALUE OF PLASMA NGAL:HEPCIDIN-25 FOR MAJOR ADVERSE KIDNEY EVENTS AFTER CARDIAC SURGERY WITH CARDIOPULMONARY BYPASS: A PILOT STUDY

Background and Aims

Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin-25 appear to be involved in catalytic iron-related kidney injury after cardiac surgery with cardiopulmonary bypass. We aimed to explore the predictive value of plasma NGAL, plasma hepcidin-25, and the plasma NGAL:hepcidin-25 ratio for major adverse kidney events after cardiac surgery.

Method

We compared the predictive value of plasma NGAL, hepcidin-25, and NGAL:hepcidin-25 with those of serum creatinine (Cr), and urinary output and urinary protein for primary endpoint major adverse kidney events (MAKE; acute kidney injury [AKI] stages 2 and 3, persistent AKI &gt; 48 hrs, acute dialysis, and in-hospital mortality) and secondary-endpoint AKI in 100 cardiac surgery patients at intensive care unit (ICU) admission. We performed ROC curve, logistic regression, and reclassification analyses.

Results

At ICU admission, plasma NGAL, plasma NGAL:hepcidin-25, and Cr predicted MAKE (area under the ROC curve [AUC]: 0.77 [95% confidence interval (CI) 0.60–0.94], 0.79 [0.63–0.95], 0.74 [0.51–0.97]) and AKI (0.73 [0.53–0.93], 0.89 [0.81–0.98], 0.70 [0.48–0.93]). For AKI prediction, NGAL:hepcidin-25 had a higher discriminatory power than Cr (AUC difference 0.26 [95% CI 0.00–0.53]). Urinary output and protein, plasma lactate, C-reactive protein, creatine kinase myocardial band, and brain natriuretic peptide did not predict MAKE or AKI (AUC &lt; 0.70). Only plasma NGAL:hepcidin-25 correctly reclassified patients for MAKE or AKI (category-free net reclassification improvement: 0.82 [95% CI 0.12–1.52], 1.03 [0.29–1.77]). After adjustment to the Cleveland risk score, plasma NGAL:hepcidin-25 ≥ 0.9 independently predicted MAKE (adjusted odds ratio 16.34 [95% CI 1.77–150.49], P = 0.014), whereas Cr did not.

Conclusion

NGAL:hepcidin-25 is a promising plasma marker for predicting postoperative MAKE.

NGAL/hepcidin-25 ratio and AKI subtypes in patients following cardiac surgery: a prospective observational study

Background

Acute kidney injury (AKI) subtypes combining kidney functional parameters and injury biomarkers may have prognostic value. We aimed to determine whether neutrophil gelatinase-associated lipocalin (NGAL)/hepcidin-25 ratio (urinary concentrations of NGAL divided by that of hepcidin-25) defined subtypes are of prognostic relevance in cardiac surgery patients.

Methods

We studied 198 higher-risk cardiac surgery patients. We allocated patients to four groups: Kidney Disease Improving Global Outcomes (KDIGO)-AKI-negative and NGAL/hepcidin-25 ratio-negative (no AKI), KDIGO AKI-negative and NGAL/hepcidin-25 ratio-positive (subclinical AKI), KDIGO AKI-positive and NGAL/hepcidin-25 ratio-negative (clinical AKI), KDIGO AKI-positive and NGAL/hepcidin-25 ratio-positive (combined AKI). Outcomes included in-hospital mortality (primary) and long-term mortality (secondary).

Results

We identified 127 (61.6%) patients with no AKI, 13 (6.6%) with subclinical, 40 (20.2%) with clinical and 18 (9.1%) with combined AKI. Subclinical AKI patients had a 23-fold greater in-hospital mortality than no AKI patients. For combined AKI vs. no AKI or clinical AKI, findings were stronger (odds ratios (ORs): 126 and 39, respectively). After adjusting for EuroScore, volume of intraoperative packed red blood cells, and aortic cross-clamp time, subclinical and combined AKI remained associated with greater in-hospital mortality than no AKI and clinical AKI (adjusted ORs: 28.118, 95% CI 1.465–539.703; 3.737, 95% CI 1.746–7.998). Cox proportional hazard models found a significant association of biomarker-informed AKI subtypes with long-term survival compared with no AKI (adjusted ORs: pooled subclinical and clinical AKI: 1.885, 95% CI 1.003–3.542; combined AKI: 1.792, 95% CI 1.367–2.350).

Conclusions

In the presence or absence of KDIGO clinical criteria for AKI, the urinary NGAL/hepcidin-25-ratio appears to detect prognostically relevant AKI subtypes.

Trial registration number

NCT00672334, clinicaltrials.gov, date of registration: 6th May 2008, https://clinicaltrials.gov/ct2/show/NCT00672334.

Graphic abstract

Definition of AKI subtypes: subclinical AKI (KDIGO negative AND Ratio-positive), clinical AKI (KDIGO positive AND Ratio-negative) and combined AKI (KDIGO positive AND Ratio-positive) with urinary NGAL/hepcidin-25 ratio-positive cut-off at 85% specificity for in-hospital death. AKI, acute kidney injury. AUC, area under the curve. NGAL, neutrophil gelatinase-associated lipocalin. KDIGO, Kidney Disease Improving Global Outcomes Initiative AKI definition.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40620-021-01063-5.

C-terminal and intact FGF23 in kidney transplant recipients and their associations with overall graft survival

Background

Increased fibroblast growth factor 23 (FGF23) is a risk factor for mortality, cardiovascular disease, and progression of chronic kidney disease. Limited data exist comparing the association of either c-terminal FGF23 (cFGF23) or intact FGF23 (iFGF23) in kidney transplant recipients (KTRs) with overall (all-cause) graft loss.

Methods

We conducted a prospective observational cohort study in 562 stable kidney transplant recipients. Patients were followed for graft loss and all-cause mortality for a median follow-up of 48 months.

Results

During a median follow-up of 48 months, 94 patients had overall graft loss (primary graft loss or death with functioning graft). Both cFGF23 and iFGF23 concentrations were significantly higher in patients with overall graft loss than those without (24.59 [11.43–87.82] versus 10.67 [5.99–22.73] pg/ml; p < 0.0001 and 45.24 [18.63–159.00] versus 29.04 [15.23–60.65] pg/ml; p = 0.002 for cFGF23 and iFGF23, respectively). Time-dependent ROC analysis showed that cFGF23 concentrations had a better discriminatory ability than iFGF23 concentrations in predicting overall (all-cause) graft loss. Cox regression analyses adjusted for risk factors showed that cFGF23 (HR for one unit increase of log transformed cFGF23: 1.35; 95% CI, 1.01–1.79; p = 0.043) but not iFGF23 (HR for one unit increase of log transformed iFGF23: 0.97; 95% CI, 0.75–1.25; p = 0.794) was associated with the overall graft loss.

Conclusion

Elevated cFGF23 concentrations at baseline are independently associated with an increased risk of overall graft loss. iFGF23 measurements were not independently associated with overall graft loss. The cFGF23 ELISA might detect bioactive FGF23 fragments that are not detected by the iFGF23 ELISA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02329-7.

Inferior vena cava-syndrome

Inferior vena cava syndrome (IVCS) is caused by agenesis, compression, invasion, or thrombosis of the IVC, or may be associated with Budd-Chiari syndrome. Its incidence and prevalence are unknown. Benign IVCS is separated from malignant IVCS. Both cover a wide clinical spectrum reaching from asymptomatic to highly symptomatic cases correlated to the underlying cause, the acuity, the extent of the venous obstruction, and the recruitment and development of venous collateral circuits. Imaging is necessary to determine the underlying cause of IVCS and to guide clinical decisions. Interventional therapy has changed the therapeutic approach in symptomatic patients. This article provides an overview over IVCS and focuses on interventional therapeutic methods and results.

Relationship Between Vitamin D and Hormones Important for Human Fertility in Reproductive-Aged Women

Vitamin D deficiency is very common in women of reproductive age. Studies in animals suggests a link between vitamin D and reproductive hormone biosynthesis. A systematic analysis of the correlation of reproductive hormones in reproductive-aged women with both total and free vitamin D was, however, not done so far. This cross-sectional study was performed in 351 healthy reproductive age Caucasian women (median age, 28.0 years; interquartile ranges, 24.7-31.0 years). We measured serum levels of both total and free 25(OH)D, endocrinological, hematological and biochemical parameters. Spearman's rank correlations were performed to assess the correlation between 25(OH)D metabolites and selected parameters. Total vitamin D and free vitamin D measurements correlated well (rho=0.912, p < 0.0001). Both total 25(OH)D and free 25(OH)D showed significant negative correlation with FAI (rho=-0.229, p<0.0001 and rho=-0.195, p<0.0001 for total and free 25(OH)D, respectively); LH (rho=-0.177, p=0.001 and rho=-0.114, p=0.04 for total and free 25(OH)D, respectively), testosterone (rho=-0.174, p=0.001 and rho=-0.190, p<0.0001 for total and free 25(OH)D, respectively) and AMH (rho=-0.130, p=0.015 and rho=-0.107, p=0.047 for total and free 25(OH)D, respectively). Our study showed comparable correlations of both total and free 25(OH)D with endocrinological parameters, i.e. inverse correlations with free androgen index, luteinizing hormone, testosterone, LH/FSH ratio, androstenedione and anti-Müllerian hormone, and also with hematological and biochemical parameters, i.e. inverse correlations with erythrocytes, hsCRP and leukocytes count, and positive correlation with transferrin saturation, mean corpuscular hemoglobin and mean corpuscular volume in healthy reproductive age women.

Superior vena cava syndrome

The superior vena cava syndrome (SVCS) is caused by compression, invasion, and/or thrombosis of the superior vena cava and/or the brachiocephalic veins. Benign SVCS is separated from malignant SVCS. SVCS comprises a broad clinical spectrum reaching from asymptomatic cases to rare life-threatening emergencies with upper airway obstruction and increased intracranial pressure. Symptoms are correlated to the acuity and extent of the venous obstruction and inversely correlated to the development of the venous collateral circuits. Imaging is necessary to determine the exact underlying cause and to guide further interventions. Interventional therapy has widely changed the therapeutic approach in symptomatic patients. This article provides an overview over this complex syndrome and focuses on interventional therapeutic methods and results.

The Effects of Intensive Versus Routine Treatment in Patients with Acute Kidney Injury

BACKGROUND

In patients with acute kidney injury (AKI), specialized treatment-initiated in response to an early-warning system- may be beneficial compared with routine treatment.

METHOD

To explore effect estimators in a pilot trial (DRKS00010530), patients with AKI on regular wards of a university hospital were treated either in the usual way (control group) or more intensively (intervention group). The subjects were allotted randomly to the two treatment groups. The more intensive treatment consisted of an early warning system for a rise in the serum creatinine concentration, immediate consultation of a specialist, and the issuance of a patient kidney passport. The primary endpoint was recovery of renal function after AKI during the index hospitalization. Renal complications and process indicators were the secondary endpoints.

RESULTS

The proportion of patients whose renal function returned to baseline after AKI was 50% in the intervention group (N = 26) and 42% in the control group (N = 26) (odds ratio 1.4, 95% confidence interval [0.5; 4.0], p = 0.58). The calculated glomerular filtration rate went down, from hospital admission to discharge, by 3 mL/min/1.73 m2 (1st-3rd quartile: [6; -20]) in the intervention group and by 13 mL/min/1.73 m2 in the control group (1st-3rd quartile: [0; -25]; p = 0.09). Complications of AKI such as hyperkalemia, pulmonary edema, and renal acidosis were rarer in the intervention group (15% versus 39%; p = 0.03). In the intervention group, compared with the control group, the cause of AKI was identified more frequently (27% versus 4%; p = 0.05); drugs with relevance to the kidney were discontinued more frequently (65% versus 31%; p = 0.01); and the diagnosis of AKI was more frequently documented in the patient's chart (58% versus 37%; p = 0.03).

CONCLUSION

Specialized consultations supported by an early warning system for AKI seem to be beneficial for patients. The findings of this pilot trial should be verified in larger-scale randomized controlled trials.

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

Impact of maternal smoking associated lyso-phosphatidylcholine 20:3 on offspring brain development

Maternal smoking during pregnancy affects fetal neurological development. Metabolomic studies in the general population suggest that smoking is associated with characteristic metabolic alterations. We investigated the association between the maternal smoking status, the fetal metabolome and head circumference at birth, as a surrogate parameter of brain development. 320 mother/newborn pairs of the Berlin Birth Cohort were investigated. Anthropometric parameters, including head circumference, of newborns of smoking mothers, former smoking mothers, and never smoking mothers were compared to assess the impact of maternal smoking behavior. Associations between maternal smoking behavior and 163 cord blood metabolites and associations between newborn head circumference and concentrations of smoking behavior related metabolites were analysed. Male newborns of smoking mothers had a reduced head circumference when compared with newborns from former smoking and never smoking mothers (p < 0.05). Using linear regression models corrected for established confounding factors, maternal smoking during pregnancy showed an independent association with head circumference (95% CI: -0.75～-0.41 cm, p = 2.45×10^-11). In a stepwise linear regression model corrected for known confounding factors of brain growth lyso-phosphatidylcholine 20:3 (95% CI: 6.68～39.88 cm, p = 4.62×10^-4) was associated with head circumference in male offspring only. None of the metabolites were associated with head circumference of female newborns. In conclusion, maternal smoking during pregnancy impacted on male offspring's development including brain development. The smoking related metabolite lyso-phosphatidylcholine 20:3 was associated with head circumference of male offspring.

Endostatin Is an Independent Risk Factor of Graft Loss after Kidney Transplant

BACKGROUND

Endostatin is a 20-kDa C-terminal fragment of collagen XVIII, known for its ability to inhibit the proliferation of capillary endothelial cells. Previous studies suggested that circulating endostatin independently predicts incident chronic kidney disease. However, the impact of endostatin on graft loss level in kidney transplant recipients (KTRs) remains unknown.

METHODS

We conducted a prospective observational cohort study in 574 maintenance KTRs. Patients were followed for kidney graft loss and all-cause mortality during a median follow-up of 48 months. Serum-, and urine-samples and clinical data were collected at baseline. Serum Endostatin concentration was analyzed by an ELISA.

RESULTS

Among 574 patients, 37 patients had graft loss and 62 patients died. For graft loss, the optimal cut-off value based on receiver operating characteristics analysis (area under the curve 0.79, 95% CI 0.71-0.86, p < 0.001) of endostatin was 147.3 pmol/L. Kaplan-Meier curves revealed that higher serum endostatin concentrations positively correlated with graft loss (p < 0.001). Multivariable Cox regression analyses showed that baseline endostatin concentrations were significantly associated with graft loss after adjusting for graft loss risk factors (adjusted hazard ratio [HR] 8.34; 95% CI 2.19-31.72; p = 0.002). The adjusted HRs for classical graft loss risk factors such as baseline estimated glomerular filtration rate and urinary protein excretion were lower (1.91 and 5.44, respectively). In contrast to graft loss, baseline endostatin concentrations were not associated with all-cause mortality.

CONCLUSION

Increased serum endostatin at baseline is independently associated with the risk of graft loss in KTRs.

[Treatment, clinical course, and cross-sectoral information transmission in patients with acute-on-chronic kidney injury]

BACKGROUND

Delayed diagnosis and undertherapy of acute-on-chronic kidney injury (AKI-on-CKD) may trigger multiple organ injury and worsen clinical outcome.

OBJECTIVES

This study focused on description of in-hospital care and cross-sectoral information transmission of patients with AKI-on-CKD including subgroup analyses (under surgical vs. non-surgical and nephrology vs. non-nephrology care).

MATERIALS AND METHODS

At a university clinic, we analysed clinical measures and documentation in patients with AKI-on-CKD. Cox regression was performed to identify independent risk factors for in-hospital-mortality and 180-day mortality.

RESULTS

In 38 (25.3%) of 150 patients, progressing AKI-on-CKD was found. Nineteen patients (12.7%) received acute dialysis. Thirty patients (20.0%) died in hospital. Systemic hypotension (n = 76, 50.7%) and nephrotoxins (n = 26, 17.3%), both considered as causes for AKI-on-CKD, were treated in 36.8 and 19.2%, respectively, of affected patients. Fluid balance was documented in one third of patients. Nephrology referral was requested in 38 (25.3%) of patients (median 24.0 h after AKI-on-CKD start). Acute renal complications (n = 74, 49.3%) were an independent risk factor for in-hospital mortality (ExpB 6.5, p = 0.022) or 180-day mortality (ExpB 3.3, p = 0.034). Rarely, outpatient physicians were informed about AKI-on-CKD (n = 42, 28.0%) or renal function follow-up was recommended (n = 14, 11.7% of surviving patients).

CONCLUSIONS

Care gaps in therapy and cross-sectoral information transmission in patients with AKI-on-CKD were identified.

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.

Free 25-Vitamin D Is Correlated with Cardiovascular Events in Prevalent Hemodialysis Patients but Not with Markers of Renal Mineral Bone Disease

Free vitamin D is the biologically active form of vitamin D. Vitamin D deficiency is associated with cardiovascular disease, the most common cause of mortality in hemodialysis patients. The goal of our current study was to investigate the relation between blood concentrations of free 25-hydroxyvitamin D with cardiovascular events in end-stage chronic kidney disease patients on hemodialysis, because this is unknown so far. We measured free vitamin D levels in 117 stable consecutive prevalent patients in September as a surrogate of vitamin D exposure during the past 6 months, and recorded the number of cardiovascular events during the previous 6 months defined as hospitalization due to heart failure, episodes of acute coronary syndrome, and stroke. Fourteen events occurred during the observation period. In patients without any cardiovascular events the free vitamin D levels were significantly higher as compared to those with cardiovascular events (patients without events: 5.68 [4.37–9.27] pg/mL; patients with events: 4.74 [3.46–5.37] pg/mL, p = 0.015). This finding remained stable after multiple regression analysis considering confounding factors such as age, time on dialysis, preexisting diabetes, hypertension, and coronary heart disease. In conclusion, our study shows that free vitamin D serum concentrations are independently associated with major cardiovascular events in chronic kidney disease patients on dialysis.

Correction: Does NGAL reduce costs? A cost analysis of urine NGAL (uNGAL) & serum creatinine (sCr) for acute kidney injury (AKI) diagnosis

[This corrects the article DOI: 10.1371/journal.pone.0178091.].

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.

Clinical effects of phosphodiesterase 3A mutations in inherited hypertension with brachydactyly

Autosomal-dominant hypertension with brachydactyly is a salt-independent Mendelian syndrome caused by activating mutations in the gene encoding phosphodiesterase 3A. These mutations increase the protein kinase A-mediated phosphorylation of phosphodiesterase 3A resulting in enhanced cAMP-hydrolytic affinity and accelerated cell proliferation. The phosphorylated vasodilator-stimulated phosphoprotein is diminished, and parathyroid hormone-related peptide is dysregulated, potentially accounting for all phenotypic features. Untreated patients die prematurely of stroke; however, hypertension-induced target-organ damage is otherwise hardly apparent. We conducted clinical studies of vascular function, cardiac functional imaging, platelet function in affected and nonaffected persons, and cell-based assays. Large-vessel and cardiac functions indeed seem to be preserved. The platelet studies showed normal platelet function. Cell-based studies demonstrated that available phosphodiesterase 3A inhibitors suppress the mutant isoforms. However, increasing cGMP to indirectly inhibit the enzyme seemed to have particular use. Our results shed more light on phosphodiesterase 3A activation and could be relevant to the treatment of severe hypertension in the general population.

G-protein coupled receptor auto-antibodies in thromboangiitis obliterans (Buerger's disease) and their removal by immunoadsorption

BACKGROUND

Immunhistopathological and serological data favors an immunopathogenesis of thromboangiitis onliterans (TAO, Buerger's disease). Auto antbodies seem to play a major role. Immunoadsorption (IA) proved to be therapeutically effective. We focused on agonistic autoantibodies (agAAB) directed against G-protein coupled receptors (GPCR) and proved the hypothesis, that these agAAB might be present in TAO and that a five day course of IA might be able to eliminate these agAAB effectively.

PATIENTS AND METHODS

Between December 2012 and May 2014 11 TAO-patients were treated by IA in a five day course. AgAAB-analysis was performed using specific ELISA techniques.

RESULTS

AgAAB were detected in 9 out of 11 patients (81.8 %).Multiple agAAB were present in 7 patients (63.6 %). A clustering of agAAB directed against loop1 of the adrenergic α1-receptor and the endothelin-A-(ETA)receptor was identified, representing 72.7 % resp. 54.5 % of the patients. AgAAB directed against the angiotensin-1 (AT-1) epitope 1 or 2 were detected in 3 patients and agAAB directed against protease-activated receptor (PAR) loop1/2 were seen in 2 patients. AgAAB directed against ETA-receptor loop1 never appeared without agAAB directed against α1-receptor loop1. Immediately after a five day-course of IA agAAB were absent in 81.8 % of the total study group and in 77.8 % of all cases tested positive for agAAB before IA.

CONCLUSIONS

AgAAB directed against GPCR were identified in TAO patients with a clustering of agAAB directed against α-1-adrenergic receptor loop1 and ETA-receptor loop1. AgAA were eliminated by IA in the majority of cases. We suggest that these agAA play an important role in the pathogenesis of TAO and that their elimination might be responsible for the positive therapeutic effects reported in patients treated with IA.

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.

Chronic hypokalaemia in a hypertensive patient

Hypokalaemia in hypertensive patients is a ‘red flag’ bringing to mind various classic secondary and genetic causes related to both hypokalaemia and hypertension. We encountered a patient who had an unusual cause for his disturbance that, to our knowledge, has not been described in hypertensive patients.

Diagnostic and prognostic stratification in the emergency department using urinary biomarkers of nephron damage: a multicenter prospective cohort study

OBJECTIVES

This study aimed to determine the diagnostic and prognostic value of urinary biomarkers of intrinsic acute kidney injury (AKI) when patients were triaged in the emergency department.

BACKGROUND

Intrinsic AKI is associated with nephron injury and results in poor clinical outcomes. Several urinary biomarkers have been proposed to detect and measure intrinsic AKI.

METHODS

In a multicenter prospective cohort study, 5 urinary biomarkers (urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, urinary liver-type fatty acid binding protein, urinary interleukin-18, and cystatin C) were measured in 1,635 unselected emergency department patients at the time of hospital admission. We determined whether the biomarkers diagnosed intrinsic AKI and predicted adverse outcomes during hospitalization.

RESULTS

All biomarkers were elevated in intrinsic AKI, but urinary neutrophil gelatinase-associated lipocalin was most useful (81% specificity, 68% sensitivity at a 104-ng/ml cutoff) and predictive of the severity and duration of AKI. Intrinsic AKI was strongly associated with adverse in-hospital outcomes. Urinary neutrophil gelatinase-associated lipocalin and urinary kidney injury molecule 1 predicted a composite outcome of dialysis initiation or death during hospitalization, and both improved the net risk classification compared with conventional assessments. These biomarkers also identified a substantial subpopulation with low serum creatinine at hospital admission, but who were at risk of adverse events.

CONCLUSIONS

Urinary biomarkers of nephron damage enable prospective diagnostic and prognostic stratification in the emergency department.

Regulatory T cells ameliorate angiotensin II-induced cardiac damage

BACKGROUND

Hypertensive target organ damage, especially cardiac hypertrophy with heart failure and arrhythmia, is a major source of morbidity and mortality. Angiotensin II, a major mediator of hypertension and cardiac damage, has proinflammatory properties. Inflammation and activation of the immune system play a pivotal role in pathogenesis of hypertensive target organ damage. However, the role of immunosuppressive CD4+CD25+ regulatory T (Treg) cells in the pathogenesis of hypertensive target organ damage is unexplored.

METHODS AND RESULTS

We conducted adoptive transfer of Treg cells into angiotensin II-infused hypertensive mice. Treg cell recipients exhibited improved cardiac hypertrophy and less cardiac fibrosis despite sustained hypertension. Amelioration of cardiac morphology was accompanied by an improvement in arrhythmogenic electric remodeling, indicating the functional significance of the enhanced cardiac morphology. Delocalization of the connexin 43 gap junction protein is one of the major pathomechanisms in electric remodeling. Pronounced connexin 43 immunoreactivity was found at the lateral borders of cardiomyocytes in angiotensin II-treated mice. In contrast, connexin 43 was restricted to the intercalated disk regions in sham controls. Surprisingly, angiotensin II+Treg-treated mice showed normal connexin 43 gap junction protein localization. Adoptive Treg cell transfer resulted in a marked reduction in cardiac CD4+, CD8+, and CD69+ cell and macrophage infiltration.

CONCLUSIONS

Immunosuppressive effects of transferred Treg cells ameliorated cardiac damage and accounted for the improved electric remodeling independently of blood pressure-lowering effects. Our results provide new insights into the pathogenesis of hypertensive cardiac damage and could therefore lead to new therapeutic approaches that involve manipulation of the immune system.

Lactate in a laubenpieper

Acid-base disorders seldom kill; however, the mechanisms and associated complications certainly do. We recently encountered a patient with a mysterious lactic acidosis. The patient proved to be a most capable teacher of important lessons.

Cyclic arginine-glycine-aspartic acid peptide inhibits macrophage infiltration of the kidney and carotid artery lesions in apo-E-deficient mice

Interactions of leukocytes with the vascular endothelium culminating in their diapedesis represent not only a crucial event in immune surveillance and defense but are also critically involved in the pathogenesis of many inflammatory diseases, including atherosclerosis. Our previous in vitro studies using atomic force microscopy measurement of monocyte-endothelial cell interaction have demonstrated that a cyclic arginine-glycine-aspartic acid peptide (cRGD) inhibited their adhesion through very late antigen (alpha4beta1-integrin; VLA4)-vascular cell adhesion molecule-1 by 60% with the IC50 = 100 nM. To elucidate the potential efficacy of this peptide in vivo in preventing atherogenesis, experiments were performed in apolipoprotein E (ApoE)-deficient (-/-) mice fed a Western diet and receiving chronic treatment with cRGD peptide for 2-4 wk. In addition, some animals were subjected to a temporary carotid artery ligation while receiving the above treatment. Formation of fatty streaks and infiltration of the vascular wall with macrophages were not affected by cRGD treatment. Infiltration of the carotid artery postligation was significantly reduced in the cRGD-treated animals, as was the lipid accumulation. Furthermore, cRGD-treated ApoE-/- mice exhibited significantly lesser macrophage infiltration and lipid accumulation in the kidneys, the site of the highest expression of VLA4. These data demonstrated that cRGD peptide is a potent inhibitor of monocyte/macrophage infiltration of the injured macrovasculature and of the renal microvasculature, where it results in the attenuation of lipid accumulation. Formation of fatty streaks in the aortic root was not inhibitable by this treatment.

Nephropathy in Zucker diabetic fat rat is associated with oxidative and nitrosative stress: prevention by chronic therapy with a peroxynitrite scavenger ebselen

Zucker diabetic fat (ZDF) rats with the metabolic syndrome and hyperlipidemia develop focal and segmental sclerosis. The role of oxidative and nitrosative stress in the nephropathy in ZDF was studied. Renal histology, function, and immunohistologic and biochemical parameters of oxidative and nitrosative stress were evaluated at 8 and 22 wk of age in ZDF and Zucker lean (ZL) rats and after chronic treatment with ebselen, an antioxidant and peroxinitrite scavenger. At 8 wk, ZDF rats showed hyperglycemia, no proteinuria or nephropathy, but higher levels of dihydrobiopterin and 3-nitrotyrosine (3-NT)-modified proteins compared with age-matched ZL rats. At 22 wk, ZDF rats developed focal and segmental sclerosis, proteinuria, decreased creatinine clearance, and renal tissue levels of glutathione and tetrahydrobiopterin with further elevation in dihydrobiopterin and 3-NT-modified proteins, in contrast to age-matched ZL rats. Renal immunohistologic expression of lipid peroxidation products and 3-NT-modified proteins also increased in 22-wk-old ZDF but not in ZL rats. Chronic ebselen treatment of ZDF rats restored renal tissue levels of glutathione and tetrahydrobiopterin; prevented significant accumulation of dihydrobiopterin, lipid peroxidation products, and 3-NT-modified proteins; and ameliorated focal and segmental sclerosis, proteinuria, and fall in creatinine clearance without affecting mean BP, body weight, and blood glucose, compared with the untreated ZDF rats. Chronic ebselen therapy also ameliorated vasculopathy with lipid deposits and tubulointerstitial scarring, inflammation, and upregulated alpha-smooth muscle actin expression. These findings suggest that ZDF rats develop a progressive nephropathy with glomerular, vascular, and tubulointerstitial pathology. Oxidative and nitrosative stress predates the nephropathy, which is improved by peroxinitrite scavenger ebselen, and thus considered its cause and not consequence.

Pulmonary fibrosis and chronic lung inflammation in ET-1 transgenic mice

The pulmonary endothelin (ET) system has been implicated in the pathogenesis of chronic lung diseases such as pulmonary hypertension, asthma, chronic obstructive lung disease, idiopathic pulmonary fibrosis, and bronchiolitis obliterans. However, the etiologic role of ET-1 in these diseases has not yet been established. We recently demonstrated that ET-1 transgenic mice, generated using the human prepro-ET-1 expression cassette including the cis-acting transcriptional regulatory elements, had predominant transgene expression in lung, brain, and kidney. We used these mice in the present study to analyze the pathophysiologic consequences of long-term pulmonary overexpression of ET-1. We found that ET-1 overexpression in the lungs did not result in significant pulmonary hypertension, but did result in development of a progressive pulmonary fibrosis and recruitment of inflammatory cells (predominantly CD4-positive cells). Our study provides evidence that a long-term activated pulmonary ET system, without any other stimuli, produces chronic lymphocytic inflammation and lung fibrosis. This suggests that overexpression of ET-1 may be a central event in the pathogenesis of lung diseases associated with fibrosis and chronic inflammation, such as pulmonary fibrosis and bronchiolitis.