Behaviour of von Willebrand factor antigen in follow-up of polymyalgia rheumatica/giant cell arteritis

A genomic and epigenomic atlas of prostate cancer in Asian populations

Prostate cancer is the second most common cancer in men worldwide¹. Over the past decade, large-scale integrative genomics efforts have enhanced our understanding of this disease by characterizing its genetic and epigenetic landscape in thousands of patients^2,3. However, most tumours profiled in these studies were obtained from patients from Western populations. Here we produced and analysed whole-genome, whole-transcriptome and DNA methylation data for 208 pairs of tumour tissue samples and matched healthy control tissue from Chinese patients with primary prostate cancer. Systematic comparison with published data from 2,554 prostate tumours revealed that the genomic alteration signatures in Chinese patients were markedly distinct from those of Western cohorts: specifically, 41% of tumours contained mutations in FOXA1 and 18% each had deletions in ZNF292 and CHD1. Alterations of the genome and epigenome were correlated and were predictive of disease phenotype and progression. Coding and noncoding mutations, as well as epimutations, converged on pathways that are important for prostate cancer, providing insights into this devastating disease. These discoveries underscore the importance of including population context in constructing comprehensive genomic maps for disease.

Mechanisms in endocrinology: The spectrum of haemostatic abnormalities in glucocorticoid excess and defect

Glucocorticoids (GCs) target several components of the integrated system that preserves vascular integrity and free blood flow. Cohort studies on Cushing's syndrome (CS) have revealed increased thromboembolism, but the pathogenesis remains unclear. Lessons from epidemiological data and post-treatment normalisation time suggest a bimodal action with a rapid and reversible effect on coagulation factors and an indirect sustained effect on the vessel wall. The redundancy of the steps that are potentially involved requires a systematic comparison of data from patients with endogenous or exogenous hypercortisolism in the context of either inflammatory or non-inflammatory disorders. A predominant alteration in the intrinsic pathway that includes a remarkable rise in factor VIII and von Willebrand factor (vWF) levels and a reduction in activated partial thromboplastin time appears in the majority of studies on endogenous CS. There may also be a rise in platelets, thromboxane B2, thrombin-antithrombin complexes and fibrinogen (FBG) levels and, above all, impaired fibrinolytic capacity. The increased activation of coagulation inhibitors seems to be compensatory in order to counteract disseminated coagulation, but there remains a net change towards an increased risk of venous thromboembolism (VTE). Conversely, GC administered in the presence of inflammation lowers vWF and FBG, but fibrinolytic activity is also reduced. As a result, the overall risk of VTE is increased in long-term users. Finally, no studies have assessed haemostatic abnormalities in patients with Addison's disease, although these may present as a consequence of bilateral adrenal haemorrhage, especially in the presence of antiphospholipid antibodies or anticoagulant treatments. The present review aimed to provide a comprehensive overview of the complex alterations produced by GCs in order to develop better screening and prevention strategies against bleeding and thrombosis.

Systematic review on the effect of glucocorticoid use on procoagulant, anti-coagulant and fibrinolytic factors

BACKGROUND

Whether glucocorticoid use contributes to a hypercoagulable state, and thereby enhances the thrombotic risk, is controversial.

OBJECTIVE

We aimed to examine the effects of glucocorticoid use on coagulation and fibrinolysis.

METHODS

MEDLINE and EMBASE databases were searched to identify published studies comparing glucocorticoid treatment with a glucocorticoid-free control situation. Subjects could be either patients or healthy volunteers. Two investigators independently performed study selection and data extraction. Results were expressed as standardized mean difference, if possible; data were pooled with a random-effects model.

RESULTS

Of the 1967 identified publications, 36 papers were included. In healthy volunteers, a clear rise in factor (F)VII, VIII and XI activity was observed after glucocorticoid treatment, but these data alone provided insufficient evidence to support hypercoagulability. However, during active inflammation, glucocorticoids significantly increased levels of plasminogen activator inhibitor-1 (PAI-1), whereas levels of von Willebrand factor (VWF) and fibrinogen decreased. Peri-operative use of glucocorticoids inhibited the increase in tissue-type plasminogen activator induced by surgery.

CONCLUSIONS

The present study showed differential effects of glucocorticoids depending on the clinical situation in which it is given, most likely as a result of their disease modifying properties. Clinical outcome studies are needed to adequately assess the risk-benefit of glucocorticoid use per population when thrombotic complication is the focus.

[Physiopathological data of Horton's syndrome]

GREAT PROGRESS: The understanding of the physiopathology of Horton's syndrome has been made in view of the prevalence of the disease, the access to affected tissue and new molecular biology techniques. And it is now possible to specify the intricacy between the genetic, immunological and vascular components. HORTON'S SYNDROME, A GENETIC DISEASE: The preferential association of the disease with some alleles pf the HLA DR4 group has helped to emphasize the fundamental role of a few amino acids of the second hypervariable area of the HLA-DR molecule. An immunogenetic predisposition appears favourable, or even necessary, for the development of the disease. HORTON'S SYNDROME, AN IMMUNOLOGICAL DISEASE: The temporal arteries of patients presenting with Horton's syndrome are infiltrated by polymorphous inflammatory cells, fundamentally including CD4 T-cell lymphocytes, macrophages, and a few giant cells. Some CD4 lymphocytes have undergone clonal proliferation and show signs of recent antigenic recognition. A fraction of them secrete interferon gamma, which plays a crucial role in the onset, maintenance and orientation of the immunological response. The macrophages play multiple roles notably in maintaining the inflammatory reaction, but also in the destruction of certain structures of the arterial wall. HORTON'S SYNDROME, A VASCULAR DISEASE: The destruction of the arterial wall at the acute stage of the disease appears responsible, sometimes later on, for aneurismal dilatations observed on the aorta of certain patients. Moreover, intimal hyperplasia (mediated by the PDGF (platelet derived growth factor) A and B) and thrombosis (related to the inflammation) join up in reducing the arterial flow and enhancing the risk of ischemic complications during the acute stage. PATHOGENESIS, HYPOTHESES: Various candidate-antigens have been incriminated in the onset of the inflammatory reaction during Horton's syndrome. Some epidemiological and molecular studies are in favour of an exogenous antigen, possibly infectious, but no evidence has been demonstrated in the studies published. A parietal, endogenous antigen might also be at the origin of the cascade of events described during this disease.

Von Willebrand factor antigen in assessment of vasculitis in patients with connective tissue diseases

Von Willebrand factor antigen (vWF:Ag) is synthesized and secreted by endothelial cells. In the present study we tried to assess the relationship between plasma level of vWF:Ag and vascular damage in patients with vasculitis. The study was carried out on 59 patients with connective tissue diseases. Vasculitis was diagnosed by biopsies of the skin. The patients with vasculitis had a significantly elevated level of vWF:Ag; however, no significant correlation between the amount of plasma vWF:Ag and the degree of vasculitis was found. The obtained results show that the plasma level of vWF:Ag may reflect the presence of vascular, especially endothelial, damage in patients with connective tissue diseases.

Endothelium damage and von Willebrand factor antigen

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D-penicillamine and rheumatoid factor

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Plasminogen activator inhibitor and von Willebrand factor in polymyalgia rheumatica

Endothelial cell products, plasminogen activator inhibitor (PAI) and von Willebrand factor (vWF), were assayed in 25 patients with newly-diagnosed and untreated polymyalgia rheumatica (PMR), before and after three and 12 months of corticosteroid treatment. The mean values of PAI and vWF, and also the levels of acute phase reactants (erythrocyte sedimentation rate, fibrinogen, haptoglobin, orosomucoid, C-reactive protein) and platelet counts, were elevated in the active untreated disease. In contrast to the acute phase proteins, both PAI and vWF remained increased after three and 12 months of glucocorticoid treatment. This suggested an active vasculitis, despite a clinically-inactive disease. Particularly high levels of vWF both before and after glucocorticoid therapy were found in two patients who subsequently developed vascular complications during the follow-up period.

Plasma and serum von Willebrand factor antigen concentrations in connective tissue disorders

Concentrations of serum and plasma von Willebrand factor antigen were measured in over 200 patients with a variety of connective tissue diseases, and in control samples from over 200 asymptomatic individuals. This comprehensive study found the highest concentrations of von Willebrand factor antigen in patients with vasculitis, Sjögren's syndrome, Felty's syndrome, giant cell arteritis and polyarteritis nodosum. Raised values were also found in rheumatoid arthritis, systemic lupus erythematosus, polymyalgia rheumatica, systemic sclerosis, Raynaud's syndrome, Takayasu's arteritis and Wegener's granulomatosis, but not in oesteoarthritis. It is possible that the difference in von Willebrand factor antigen concentrations in two sub-groups of systemic necrotising arteritis (Wegener's granulomatosis and polyarteritis nodosum) may imply different disease processes. The large numbers involved have allowed us to confirm or question smaller studies of the role of this molecule in connective tissue disease.

Laboratory investigations including liver in polymyalgia rheumatica/giant cell arteritis

The most useful investigation in supporting the clinical diagnosis of PMR/GCA is elevation of the ESR or viscosity. Acute phase proteins, particularly C-reactive protein, are also elevated but in most cases are not more helpful than the ESR in either diagnosis or follow-up. The definitive investigation is the demonstration of giant cell arteritis histologically, usually from temporal artery biopsy. The classical changes are internal elastic lamina fragmentation and destruction, with marked intimal thickening and an inflammatory infiltrate in the vessel wall with giant cells. Changes of healed arteritis can be distinguished from ageing changes and can therefore confirm the diagnosis. Positive biopsies are found in about 70% of patients with clinical GCA but are unlikely to be helpful in pure PMR. Elevation of alkaline phosphatase of liver origin is seen in one-third to half of patients with both PMR and GCA. Abnormal tracer uptake has been reported in radionuclide scans with a variety of non-specific abnormalities on liver biopsy. Promising developments include measurement of CD8+ lymphocytes and interleukins.