Faculty Bibliography

Venous thromboembolism (VTE), comprised of deep vein thrombosis and pulmonary embolism, is a common health problem both in the United States and worldwide, with significant associated morbidity and mortality. Despite multiple known genetic and situational risk factors, an estimated 30% of all events remain classified as idiopathic, demonstrating a significant knowledge gap in the pathophysiology VTE. While platelets are well established as an essential contributor to thrombus formation and there has been recent interest in the role of neutrophil extracellular traps, specific cell types and pathways involved in the pathogenesis of VTE remain uncertain. In this study, our primary aims were to define a unique transcriptional signature for VTE and to identify the types of cells and specific pathways involved in development of VTE. Whole blood was collected in PAX gene tubes and RNA sequencing for coding mRNA was performed in an unbiased manner in 201 patients with prevalent VTE as well as 43 healthy controls. We used a bioinformatics approach to develop a unique signature for VTE by identifying differentially expressed genes, developing cell-type modules, and ascertaining pathways driving differentially expressed transcripts. We performed additional analyses on subgroups of patients with idiopathic VTE, patients with incident VTE, and VTE patients matched to healthy controls by age and sex. We went on to use machine learning methods to learn models that best differentiate VTE patients from healthy controls and validated it on a left out test set within our VTE population. Genes specific to neutrophils, erythrocytes, and platelets, in that order, were most significantly upregulated in patients with VTE compared to healthy controls. Genes related to T-cells were downregulated. Pathway analysis revealed upregulated neutrophil activation and degranulation, erythrocyte differentiation and homeostasis, and platelet degranulation. A gene signature of 217 transcripts was outstanding at differentiating patients with VTE versus healthy controls (AUC 0.94). Following adjustment for age, sex, and race/ethnicity our genetic signature remained significantly robust at differentiating patients with VTE versus controls (AUC 0.83). Our expression signature remained stable across patients with idiopathic VTE (AUC 0.93), and in patients who went on to develop future VTE events (AUC 0.95). In summary, we have demonstrated a whole blood transcriptional signature for prevalent and incident VTE. Genes related to neutrophils, erythrocytes, and platelets are upregulated in patients with VTE and genes related to T-cells were downregulated. These findings suggest an active role of cell types once thought to be passively entrapped within thrombus and provide new areas of study to establish the pathophysiology of VTE

Background/Purpose: Psoriatic arthritis (PsA) and Psoriasis (PsO) are chronic inflammatory diseases associated with vascular inflammation and increased CVD risk. Few studies have examined vascular inflammatory differences between PsO and PsA and how these differences may impart a different CVD risk profile. We directly investigated the vascular endothelium of patients with PsA, PsO and compared to controls to better understand the inflammatory mechanism(s) that predispose psoriatic patients to CVD risk.
Method(s): Twenty patients with psoriatic disease (PD) (mean age 45 years, 55% male, 11.2 +/- 19% body surface area (BSA) involvement) were first compared to 10 matched controls. Next, comparisons were made between PsO (n = 14, average age 50 years, 57% male, 11 +/- 22% BSA) and active PsA (n = 6, average age 36 years, 50% male, 11 +/- 10% BSA, average 2 - 3 tender/swollen joints per individual). To measure vascular endothelial health, venous endothelial cells were collected from the brachial vein using guidewires inserted through an angiocatheter and isolated with CD146-conjugated magnetic beads. Following collection, endothelial mRNA was isolated, converted to cDNA and inflammatory gene profiling performed by RT-qPCR with Taqman probes and primers. Transcripts were chosen based on in vitro gene arrays of human aortic endothelial cells co-stimulated with IL-17 and TNF-alpha.
Result(s): PD patients compared to controls showed a trend towards higher levels of hs-CRP (2.4 +/- 4 mg/dl vs. 0.8 +/- 2 mg/ dl, p = 0.08) with no overall difference noted between PsA and PsO patients (2.8 +/- 2 mg/dl vs. 2.7 +/- 4 mg/dl, p = 0.24). Transcriptomic profiling of venous endothelial cells comparing PD (PsO and PsA) to controls revealed upregulation of inflammatory cytokine- and chemokine- associated transcripts (lymphotoxin beta [4 - fold], CCL3 [11 - fold], CXCL10 [16 - fold], IL-8 [10 - fold] and IL-1beta [4 - fold], P < 0.05 for all) and transcripts related to intracellular adhesion (ICAM1 [2.4 - fold] and inflammation COX-2 [3 - fold], P < 0.05). Increased expression of the chemokine fractalkine (CX3CL1 [2.8 - fold], p < 0.05) and lymphotoxin beta [2 - fold, p = 0.10] were found in patients with active PsA compared to PsO. No differences in CCL3, CXCL10, IL-8, IL-1B, ICAM1 and COX-2 where seen between PsA and PsO patients.
Conclusion(s): Endothelial cell pro-inflammatory transcripts are upregulated in patients with active PD compared with controls. Levels of lymphotoxin beta and fractalkine, a chemokine present in inflamed arthritic synovial tissue, are greater in endothelial cells of patients with PsA than PsO. These findings may underlie increased CVD risk in patients with PD and highlight the inflammatory vascular differences between PsO and PsA