John A. Reynolds

25-Hydroxyvitamin D deficiency is associated with increased aortic stiffness in patients with systemic lupus erythematosus

Objective. To determine the relationship between serum vitamin D and markers of subclinical cardiovascular disease (CVD) in patients with SLE. Methods. We recruited SLE patients (≥4 ACR 1997 criteria) from outpatient clinics between January 2007 and January 2009. Vitamin D deficiency was defined as serum 25(OH)D <20 ng/ml measured by ELISA. Disease activity was measured using the SLEDAI-2K score. Aortic pulse wave velocity (aPWV) was measured using PulseTrace 3600 (Micromedical) and carotid plaque (CP) and intima–media thickness (IMT) assessed using B-mode Doppler US. Results. Seventy-five women with SLE were recruited with a median (interquartile range) disease duration of 16 (8–27) years. Patients with vitamin D deficiency had higher BMI (P = 0.014) and insulin resistance (P = 0.023) than those with 25(OH)D >20 ng/ml. Subjects with SLEDAI-2K ≥4 had lower 25(OH)D than those with SLEDAI-2K <4 (median 12.9 vs 20.3 ng/ml, P = 0.031). Aortic stiffness was significantly associated with serum 25(OH)D [log(aPWV) β (95% CI) −0.0217 (−0.038, −0.005), P = 0.010] independently of BMI, CVD risk factors and serum insulin. Adjustment for disease activity reduced the strength of the association. There was no association between 25(OH)D and CP or IMT. Conclusions. Vitamin D deficiency is associated with increased aortic stiffness in SLE, independent of CVD risk factors and insulin. Increased inflammatory disease activity may be the mechanism by which vitamin D deficiency mediates vascular stiffness in this patient group.

Age-related impairment of endothelial progenitor cell migration correlates with structural alterations of heparan sulfate proteoglycans.

Aging poses one of the largest risk factors for the development of cardiovascular disease. The increased propensity toward vascular pathology with advancing age maybe explained, in part, by a reduction in the ability of circulating endothelial progenitor cells to contribute to vascular repair and regeneration. Although there is evidence to suggest that colony forming unit‐Hill cells and circulating angiogenic cells are subject to age‐associated changes that impair their function, the impact of aging on human outgrowth endothelial cell (OEC) function has been less studied. We demonstrate that OECs isolated from cord blood or peripheral blood samples from young and old individuals exhibit different characteristics in terms of their migratory capacity. In addition, age‐related structural changes were discovered in OEC heparan sulfate (HS), a glycocalyx component that is essential in many signalling pathways. An age‐associated decline in the migratory response of OECs toward a gradient of VEGF significantly correlated with a reduction in the relative percentage of the trisulfated disaccharide, 2‐O‐sulfated‐uronic acid, N, 6‐O‐sulfated‐glucosamine (UA[2S]‐GlcNS[6S]), within OEC cell surface HS polysaccharide chains. Furthermore, disruption of cell surface HS reduced the migratory response of peripheral blood‐derived OECs isolated from young subjects to levels similar to that observed for OECs from older individuals. Together these findings suggest that aging is associated with alterations in the fine structure of HS on the cell surface of OECs. Such changes may modulate the migration, homing, and engraftment capacity of these repair cells, thereby contributing to the progression of endothelial dysfunction and age‐related vascular pathologies.

Vitamin D improves endothelial dysfunction and restores myeloid angiogenic cell function via reduced CXCL-10 expression in systemic lupus erythematosus.

Patients with systemic lupus erythematosus (SLE) have accelerated cardiovascular disease and dysfunctional endothelial repair mechanisms. Myeloid angiogenic cells (MACs), derived from circulating monocytes, augment vascular repair by paracrine secretion of pro-angiogenic factors. We observed that SLE MACs are dysfunctional and secrete pro-inflammatory cytokines. We also found that the vitamin D receptor was transiently expressed during MAC differentiation and that in vitro, calcitriol increased differentiation of monocytes into MACs in both SLE and in a model using the prototypic SLE cytokine, interferon-alpha. The active form of vitamin D (calcitriol) restored the SLE MAC phenotype towards that of healthy subjects with reduced IL-6 secretion, and normalised surface marker expression. Calcitriol also augmented the angiogenic capacity of MACs via the down-regulation of CXCL-10. In SLE patients treated with cholecalciferol for 12 weeks, the improvement in endothelial function correlated with increase in serum 25(OH)D concentrations independently of disease activity. We also show that MACs were able to positively modulate eNOS expression in human endothelial cells in vitro, an effect further enhanced by calcitriol treatment of SLE MACs. The results demonstrate that vitamin D can positively modify endothelial repair mechanisms and thus endothelial function in a population with significant cardiovascular risk.

Improving cardiovascular outcomes in rheumatic diseases: therapeutic potential of circulating endothelial progenitor cells.

Patients with Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) have a significantly increased risk of cardiovascular disease (CVD). The reason for this is unclear but may be due, at least in part, to the failure of endothelial repair mechanisms. Over the last 15 years there has been much interest in the mechanisms of endothelial renewal and its potential as a therapy for CVD. In the circulation there are two distinct populations of cells; myeloid angiogenic cells (MACs) which augment repair by the paracrine secretion of angiogenic factors, and outgrowth endothelial cells (OECs) which are true endothelial progenitor cells (EPCs) and promote vasculogenesis by differentiating into mature endothelium. There are marked abnormalities in the number and function of these cells in patients with RA and SLE. Inflammatory cytokines including interferon-alpha (IFNα) and tumour-necrosis factor alpha (TNFα) both impair MAC and OEC function ex vivo and may therefore contribute to the CVD risk in these patients. Whilst administration of mononuclear cells, MACs and other progenitors has improved cardiovascular outcomes in the acute setting, this is not a viable option in chronic disease. The pharmacological manipulation of MAC/OEC function in vivo however has the potential to significantly improve endothelial repair and thus reduce CVD in this high risk population.

Brief Report: Endothelial Progenitor Cell Phenotype and Function Are Impaired in Childhood-Onset Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is characterized by increased cardiovascular risk in adult‐onset and childhood‐onset SLE. Type I interferons (IFNs) appear to play a prominent role in premature vascular damage in adult‐onset SLE, at least in part, by inducing impairments in the phenotype and function of endothelial progenitor cells (EPCs), thereby hampering vascular repair. It is not clear whether EPC dysfunction is present in childhood‐onset SLE in association with a type I IFN signature.

Vitamin D treatment for connective tissue diseases: hope beyond the hype?

The prevalence of vitamin D deficiency is increased among patients with CTDs. The active form of vitamin D (calcitriol) is a potent regulator of the immune system and may suppress inflammatory responses. This has led to claims that vitamin D may be a safe treatment, or a treatment adjunct, to reduce systemic inflammation in this patient population. It is important to note, however, that there is insufficient evidence from robust clinical trials to support these novel uses for vitamin D. In this review we examine the potential role of vitamin D as a treatment adjunct for CTDs. We will discuss how vitamin D may modulate the immune response and review the current evidence for using vitamin D to treat CTDs and their associated co-morbidities. We conclude that while there is much excitement about vitamin D in this context, further well-designed trials are needed to demonstrate its efficacy in the treatment of patients with CTDs.

Endothelial progenitor cell phenotype and function are impaired in childhood-onset systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by increased cardiovascular risk in adult‐onset and childhood‐onset SLE. Type I interferons (IFNs) appear to play a prominent role in premature vascular damage in adult‐onset SLE, at least in part, by inducing impairments in the phenotype and function of endothelial progenitor cells (EPCs), thereby hampering vascular repair. It is not clear whether EPC dysfunction is present in childhood‐onset SLE in association with a type I IFN signature.

Role of vitamin D in endothelial function and endothelial repair in clinically stable systemic lupus erythematosus

BACKGROUND Patients with systemic lupus erythematosus (SLE) have endothelial dysfunction and increased risk of cardiovascular disease. Endothelium-dependent dilatation (ED) is abnormal in patients with SLE, and endothelial repair mechanisms are also impaired. Myeloid angiogenic cells (MACs) promote angiogenesis to restore damaged vessels. Vitamin D deficiency is associated with cardiovascular disease in the general population and is prevalent in SLE. We aimed to assess the effect of vitamin D on endothelial repair and function. METHODS Vitamin D deficient (<20 ng/mL) patients with SLE were treated with cholecalciferol by their physician. Vitamin D replete patients (>30 ng/mL) and healthy controls (>20 ng/mL) were also recruited. Endothelial function was determined by the ratio of ED to independent dilatation (EI). MACs from patients were cultured with and without 10 nM calcitriol, and function determined by migration and angiogenesis assays. Endothelial nitric oxide synthase (eNOS) expression was studied in human aortic endothelial cells treated with tumour necrosis factor α (TNFα) and MAC-conditioned media. FINDINGS We studied 22 vitamin D deficient and 18 replete patients. Vitamin D deficient patients had an increased number of MACs compared with controls (p=0·04) but impaired migratory capacity (p=0·001) and reduced angiogenic capacity, although this was not statistically significant (p=0·13). Media from calcitriol-treated MACs significantly increased angiogenesis compared with untreated MACs (p=0·01). Calcitriol reduced IP-10 expression by MACs (p<0·0006), and blockade of IP-10 restored the angiogenic capacity of MACs from patients with SLE. In cholecalciferol-treated patients, change in 25-hydroxyvitamin D was strongly correlated with change in ED:EI (r=0·650, p=0·006) after adjustment for age (odds ratio 1·12, 95% CI 1·02-1·24; p=0·02). Media from calcitriol-treated MACs more strongly attenuated TNFα-mediated downregulation of eNOS in human aortic endothelial cells than did untreated MACs from patients with SLE (p=0·01). INTERPRETATION In this small experimental study, calcitriol improved endothelial function in patients with stable SLE. This improvement was associated with an increase in MAC number and function. The improved angiogenic capacity in MACs might be mediated via downregulation of IP-10 and changes in ED:EI by MAC regulation of eNOS in endothelial cells. The findings suggest that vitamin D could be a novel therapy to reduce cardiovascular disease in this patient group. FUNDING North West England Medical Research Council Fellowship Scheme in Clinical Pharmacology and Therapeutics (funding from UK Medical Research Council (grant number G1000417/94909), ICON, Astra Zeneca, GlaxoSmithKline, Medicines Evaluation Unit).

Brief Report: Vitamin D Deficiency Is Associated With Endothelial Dysfunction and Increases Type I Interferon Gene Expression in a Murine Model of Systemic Lupus Erythematosus

Patients with systemic lupus erythematosus (SLE) have an increased risk of cardiovascular disease (CVD) and impaired endothelial repair. Although vitamin D deficiency is associated with increased CVD risk in the general population, a causal relationship has not been demonstrated. We aimed to determine whether vitamin D deficiency directly modulates endothelial dysfunction and immune responses in a murine model of SLE.

Association Between Genetic Variation in FOXO3 and Reductions in Inflammation and Disease Activity in Inflammatory Polyarthritis

Genetic variation in FOXO3 (tagged by rs12212067) has been associated with a milder course of rheumatoid arthritis (RA) and shown to limit monocyte‐driven inflammation through a transforming growth factor β1–dependent pathway. This genetic association, however, has not been consistently observed in other RA cohorts. We sought to clarify the contribution of FOXO3 to prognosis in RA by combining detailed analysis of nonradiographic disease severity measures with an in vivo model of arthritis.