Serum Beta-Defensin-2 is a biomarker for psoriasis but not subclinical atherosclerosis: Role of IL17a, PI-3 kinase and Rac1

Background

Beta-defensins (BDs) are antimicrobial peptides secreted upon epithelial injury. Both chemotactic and antimicrobial properties of BDs function as initial steps in host defense and prime the adaptive immune system in the body. Psoriasis, a chronic immune-mediated inflammatory disease, has both visible cutaneous manifestations as well as known associations with higher incidence of cardiometabolic complications and vascular inflammation.

Objectives

We aimed to investigate the circulating expression of beta-defensin-2 (BD2) in psoriasis at baseline compared to control subjects, along with changes in BD2 levels following biologic treatment at one-year. The contribution of BD2 to subclinical atherosclerosis is also assessed. In addition, we have sought to unravel signaling mechanisms linking inflammation with BD2 expression.

Methods

Multimodality imaging as well inflammatory biomarker assays were performed in biologic naïve psoriasis (n=71) and non-psoriasis (n=53) subjects. A subset of psoriasis patients were followed for one-year after biological intervention (anti-Tumor Necrosis Factor-α (TNFα), n=30; anti-Interleukin17A (IL17A), n=21). Measurements of circulating BD2 were completed by Enzyme-Linked Immunosorbent Assay (ELISA). Using HaCaT transformed keratinocytes, expression of BD2 upon cytokine treatment was assessed by quantitative polymerase chain reaction (qPCR) and ELISA.

Results

Herein, we confirm that human circulating BD2 levels associate with psoriasis, which attenuate upon biologic interventions (anti-TNFα, anti-IL-17A). A link between circulating BD2 and sub-clinical atherosclerosis markers was not observed. Furthermore, we demonstrate that IL-17A-driven BD2 expression occurs in a Phosphatidylinositol 3-kinase (PI3-kinase) and Rac1 GTPase-dependent manner.

Conclusions

Our findings expand on the potential role of BD2 as a tractable biomarker in psoriasis patients and describes the role of an IL-17A-PI3-kinase/Rac signaling axis in regulating BD2 levels in keratinocytes.

Application of machine learning to identify top determinants of fibrofatty plaque burden by CCTA in humans with psoriasis

Introduction

Fibrofatty plaque burden (FFB) is a high-risk, vulnerable plaque feature comprised of an atheromatous core and fibrous cap with increased risk of coronary artery disease (CAD) [1]. Psoriasis (PSO) is a chronic inflammatory disease linked with atherosclerotic risk and premature cardiovascular disease, driven in part by vulnerable plaque rupture [2,3]. Machine learning (ML) previously showed the prognostic value of FFB in predicting 5-year risk of cardiac-related mortality in patients with CAD [4]. Whether ML can predict FFB in psoriasis is understudied.

Purpose

To use ML to identify top determinants of FFB by CCTA in PSO.

Methods

320 consecutive participants with psoriasis were recruited as part of an ongoing cohort study, of whom 307 had FFB analyzed with coronary computed tomography angiography (CCTA) and quantified by QAngio CT (Medis, The Netherlands). 140 out of 182 potential determinants were subjected to ML algorithms analyzed by random forest and validated by 5-fold cross validation to select the top determinants based on R-square criteria. Lipid concentration and size were measured by nuclear magnetic resonance (NMR) and sdLDL-C was calculated by Sampson's formula.

Results

The top 21 determinants of FFB at baseline were grouped into 3 categories: cardiometabolic risk factors (BMI, sex, DBP, mean arterial pressure, exercise, heart rate, glucose, anxiety, psoriasis disease duration), clinical measurements (basophils, platelets, hemoglobin, RBC, alkaline phosphatase, ALT, creatinine, neutrophil-to-lymphocyte ratio), and lipoproteins (LDL particle size, apolipoprotein A1, apolipoprotein B-to-A1 ratio, calculated sdLDL-C).

Conclusion

ML confirmed that FFB strongly correlates with cardiometabolic risk factors, clinical measurements, and lipoproteins. Further investigations into these top determinants of FFB over time may provide insight into potential therapeutic interventions that decrease cardiovascular risk in patients with chronic inflammatory diseases and should be validated in larger studies.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): This study was supported by the National Heart, Lung and Blood Institute (NHLBI) IntramuralResearch Program (ZIA-HL-06193). This research was made possible through the NIH MedicalResearch Scholars Program, a public-private partnership supported jointly by the NIH andcontributions to the Foundation for the NIH from the Doris Duke Charitable Foundation,Genentech, the American Association for Dental Research, the Colgate-Palmolive Company, andother private donors.

Bone marrow and splenic metabolic activity by 18F-FDG PET/CT are associated with noncalcified coronary burden and lipid-rich necrotic core in psoriasis

Background/Introduction

Psoriasis is an immune-mediated inflammatory skin condition with an increased risk of myocardial infarction (MI). Elevated bone marrow (BM) and splenic hematopoiesis occurs after MI. In stable patients without chronic inflammation, higher splenic hematopoiesis predicts major adverse cardiovascular events (MACE). Nevertheless, studies in humans investigating these relationships in states of chronic inflammation on coronary artery disease features associated with MACE are limited.

Purpose

To investigate the relationships between bone marrow and splenic metabolic activity by [18]-fluorodeoxyglucose (FDG) PET/CT and subclinical cardiovascular disease in psoriasis.

Methods

Healthy participants (N=30) and psoriasis participants (N=210) were age and sex matched. All participants underwent 18FDG PET/CT and CT angiography (Toshiba 320 slice). Coronary artery plaque characteristics were assessed using QAngio CT (Medis, The Netherlands) and lipid rich necrotic core (LRNC) was assessed using vascuCAP (Elucid Bioimaging, Boston, MA). For tissue metabolic activities target-to-background ratio (TBR) was calculated as the ratio of arterial and venous standardized uptake values (SUV).

Results

The psoriasis cohort was middle aged 49.2 (±SD 11.9) years and predominantly male (64%). Those with psoriasis vs. healthy participants had higher BM (1.58 (IQR 1.35–1.89) vs. 1.23 (IQR 1.14–1.35); p<0.001) and splenic (1.40 (IQR 1.21–1.66) vs.1.17 (IQR 1.11–1.26); p<0.001) metabolic activity. After adjustment for cardiovascular risk factors bone marrow metabolic activity was associated with total burden, non-calcified burden (NCB) and LRNC (β=0.36, β=0.39, β=0.26; all p<0.001) respectively. Similar findings were observed for splenic activity (β=0.33, β=0.36, β=0.36; all p<0.001). In ROC analysis, when comparing area under the curve, BM activity better incrementally predicted non-calcified burden and lipid rich necrotic core compared to splenic activity (Figure).

Conclusions

BM and splenic metabolic activity are increased in psoriasis. Both are associated with coronary artery disease but there was a slightly stronger association with BM activity compared to splenic activity, These findings warrant further study to understand immune mechanisms underlying these observations.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Heart, Lung and Blood Institute Intramural Research Program in Bethesda, Maryland Figure 1. Median values of NCB and LRNC were used to convert these continuous variables into dichotomous variables such that values ≤ median were designated as 0 and values >median were designated 1. Bone marrow model compared to base model and splenic model added incremental value in predicting NCB (p<0.0001) and LRNC (p=0.0003). Base model: Framingham risk score, lipid treatment, biologic therapy, homeostasis model assessment as an index of insulin resistance (HOMA-IR), low density lipoprotein (LDL).

MP11: COMORBID DEPRESSION OR ANXIETY IS ASSOCIATED WITH AORTIC VASCULAR INFLAMMATION AND CORONARY HEART DISEASE BEYOND TRADITIONAL CARDIOVASCULAR RISK FACTORS IN PSORIASIS

Purpose of Study

Psoriasis is a chronic inflammatory disorder associated with vascular inflammation (VI), measured by 18-fluorodeoxyglucose positron emission tomography/computed tomography (18-FDG PET/CT), and increased risk of MI. Patients with psoriasis are more likely to have comorbid depression and anxiety. Whether these comorbidities accelerate the development of CVD in psoriasis is unclear. We hypothesized that aortic VI and coronary plaque burden would be increased in patients with psoriasis who have depression and/or anxiety compared to those with psoriasis who do not.

Methods Used

Patients were prospectively enrolled. Those who reported a history of depression and/or anxiety (n=40) on survey and age- and gender-matched patients who reported no history of psychiatric illness (n=40) were selected. Target-to-Background ratio from 18FDG PET/CT was used to assess aortic VI, and coronary CT angiography scans were analyzed for coronary plaque composition.

Summary of Results

Both aortic VI and coronary plaque burden were higher in psoriasis patients with comorbid depression or anxiety compared to those without (table 1). After adjustment for Framingham Risk Score, body mass index, and statin use; VI (β=0.24, p=0.02), total plaque burden (β=0.13, p=0.04), and non-calcified burden (β=0.13, p=0.04) were associated with comorbid depression and/or anxiety.

Conclusions

Patients with psoriasis who have comorbid depression or anxiety have increased aortic VI and coronary plaque burden, suggesting that identification of psychiatric diagnoses in psoriasis may be warranted for future CV risk reduction in this high risk population.

Abstract MP11 Figure 1

21: DETERMINANTS OF VASCULAR INFLAMMATION BY 18-FLUORODEOXYGLUCOSE PET/MRI: FINDINGS FROM THE PSORIASIS, ATHEROSCLEROSIS AND CARDIOMETABOLIC DISEASE INITIATIVE

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased CV risk, provides a clinical human model to study inflammatory atherogenesis. We aimed to assess the major determinants of vascular inflammation (VI) measured by 18FDG PET-MRI in a well-phenotyped PSO cohort.

Methods Used

124 consecutive patients with PSO underwent 18FDG PET-MRI scans. We used target-to-background ratio to quantify VI 120 minutes post FDG injection. Homeostatic model assessment of insulin resistance (HOMA-IR) was measured, along with cholesterol efflux capacity (CEC) and HDL particle concentration by NMR (Liposcience) fasting.

Summary of Results

Our cohort was middle aged (mean 49±13.3 years) with mild to moderate PSO, and low CV risk (median Framingham Risk Score (FRS) 2, IQR 2–6). PSO was associated with increased VI (β=0.27, p<0.005), compared to healthy controls. VI was associated with HOMA-IR (β=0.26, p<0.001), CEC (β=−0.12, p=0.04) and HDL particle concentration (β=−0.19, p=0.003) beyond traditional CV risk factors (age, gender, FRS and BMI). Among these, HOMA-IR provided maximum incremental value in predicting VI beyond traditional risk factors (χ2=39.36, p<0.001).

Conclusions

VI by FDG PET MRI is associated with traditional CV risk factors and cardiometabolic parameters. Insulin resistance and CEC were most strongly associated with VI by 18FDG PET-MRI beyond traditional CV risk factors and BMI in PSO suggesting that cardiometabolic disease increases CV risk in PSO.

Abstract 21 Figure 1

23: VASCULAR INFLAMMATION AND AORTIC WALL CHARACTERISTICS MODULATE FOLLOWING LIFESTYLE CHANGES IN PSORIASIS PATIENTS AT 1 YEAR FOLLOW UP

Purpose of Study

Psoriasis (PSO), a chronic inflammatory skin disease, is associated with increased CV risk and vascular inflammation (VI). However, the effect of therapeutic lifestyle changes (TLC) including exercise on VI over time is unknown. We hypothesized that TLC would lead to an improvement in VI at 1 year accompanied by improvements in aortic wall characteristics.

Methods Used

65 PSO patients, recruited consecutively, underwent FDG PET/CT, phase contrast MRI scans and clinical visits for evaluation of VI, wall characteristics and exercise frequency, at baseline and 1 year follow-up. VI was measured as Target-to-background ratio (TBR), and aortic distensibility (AD) and wall thickness were assessed by commercial software on phase contrast MRI scans. Clinical parameters were ascertained by both survey and provider.

Summary of Results

VI decreased at 1 year (6.5% decrease in TBR; p<0.0001), and was inversely associated with exercise frequency beyond adjustment for CV risk factors (β=−0.27; p=0.001). Furthermore, this decrease in VI was associated with improvement in AD (40% increase; p<0.001) and aortic wall thickness (8.5% decrease; p<0.001).

Conclusions

Our findings suggest that VI improves with TLC. This 6.5% decrease in VI could lead to ∼30% reduction in future adverse events, based on a recent large prospective study. This VI reduction is also associated with improved aortic wall characteristics suggesting that targeting VI as a surrogate marker holds promise to understand the effects of TLC on CV disease.

Abstract 23 Figure 1

18: IMPROVEMENT IN PSORIASIS SKIN DISEASE SEVERITY IS ASSOCIATED WITH REDUCTION OF CORONARY PLAQUE BURDEN

Purpose of Study

Psoriasis (PSO), a chronic inflammatory disease associated with increased cardiovascular (CV) risk, provides a clinical human model to study inflammatory atherogenesis. While PSO severity is associated with both in vivo vascular disease and future CV risk, the longitudinal impact of PSO severity on coronary disease progression is unknown. We hypothesized that an improvement in PSO severity may lead to a reduction in coronary plaque burden by coronary CT angiography (CCTA).

Methods Used

Consecutively recruited PSO patients (N=50) underwent CCTA (320 detector row, Toshiba) and cardiometabolic profiling at baseline and 1-year follow-up. Total (TB) and non-calcified (NCB) coronary plaque burden were quantified using QAngio (Medis, Netherlands). PSO severity was measured as the psoriasis area severity index (PASI). The longitudinal change in coronary plaque burden was analyzed with unadjusted and adjusted regression.

Summary of Results

The cohort had a low Framingham Risk Score and mild to moderate PSO. Patients whose PSO severity improved (ΔPASI −27%; p<0.001) (N=33) had significant improvement in TB (β=0.40, p=0.003) and NCB (β=0.49, p<0.001) (table 1), beyond adjustment for traditional CV risk factors, BMI, statin use, & systemic/biologic PSO therapy.

Conclusions

Improvement in PSO severity was associated with improvement in coronary plaque burden by CCTA. Our study suggests that a reduction in skin inflammation may reduce the progression of early, non-calcified coronary plaque. Larger studies are needed to confirm these findings.

Abstract 18 Figure 1

*P-value is calculated by comparing baseline and 1-year follow-up values for variables using paired t-test for continuous variables, and Pearson's chi-squared test for categorical variables. All values are expressed as Mean±SD, unless specified otherwise. PASI: Psoriasis Area Severity Index.