Endothelial function and its implications for cardiovascular and renal disease in systemic lupus erythematosus

Diverse vascular lesions in systemic lupus erythematosus and clinical implications

PURPOSE OF REVIEW

Vascular injury is one of the typical symptoms of systemic lupus erythematosus (SLE), and may play a key role in the choice of treatment strategy and prediction of prognosis. In this review, diverse vascular lesions in SLE and their clinical significance are discussed.

RECENT FINDINGS

The clinical features of vascular disease in SLE differ from organ to organ, and may be extreme with regard to renal vascular lesions. Vascular lesions in SLE may be of inflammatory or thrombotic origin, and immune system dysfunction is considered to be a predominant feature. Numerous lines of evidence suggest that the activation and injury of endothelial cells might play a key role in the pathogenesis.

SUMMARY

Vascular lesions in SLE are mediated by a complex interaction between the immune system and other contributing factors. Different therapies developed for vascular lesions, both immunosuppressive and nonimmunosuppressive, should be selected based on the different clinical and pathological characteristics, and our future understanding of the different mechanisms involved.

Inclusion of renal vascular lesions in the 2003 ISN/RPS system for classifying lupus nephritis improves renal outcome predictions

The 2003 International Society of Nephrology/Renal Pathology Society (ISN/RPS) pathological classification system of lupus nephritis specified the importance of vascular damage and indicated this should be included in the diagnostic summary. Few pathological studies of lupus nephritis, however, focus on the patterns of renal vascular involvement. Here we assessed renal vascular lesions in lupus nephritis based on the 2003 ISN/RPS classification system and evaluated their association with clinical and pathological data in a large cohort from a single center in China. Among 341 patients with lupus nephritis, 279 were diagnosed with single or multiple renal vascular lesions that included 253 with vascular immune complex deposits, 82 with atherosclerosis, 60 with thrombotic microangiopathy, 13 with noninflammatory necrotizing vasculopathy, and 2 with true renal vasculitis. Patients with thrombotic microangiopathy had the poorest renal outcome. In multivariate Cox hazard analysis after inclusion of renal vascular lesions, the new chronicity index score became a significantly better independent risk factor for renal outcome (hazard ratio 2.32). Thus, renal vascular lesions are common in lupus nephritis and closely correlate with clinical disease activity and renal outcome. Inclusion of a detailed description of renal vascular lesions in the ISN/RPS classification of lupus nephritis may strengthen its predictive value for renal outcome.

Dysregulation of the microvasculature in nonlesional non-sun-exposed skin of patients with lupus nephritis

OBJECTIVE

Membrane endothelial protein C receptor (mEPCR) is highly expressed in peritubular capillaries of kidneys from patients with active and poorly responsive lupus nephritis (LN). We investigated the hypothesis that changes in the microvasculature are widespread with extension to the dermal vasculature.

METHODS

Skin biopsies from uninvolved skin (buttocks) were performed in 27 patients with LN and 5 healthy controls. Sections were stained with specific antibodies reactive with mEPCR, adiponectin, intercellular adhesion molecule-1 (ICAM-1), and CD31; then assessed by enumeration of stained blood vessels (percentage positive blood vessels) blinded to knowledge of clinical information.

RESULTS

There was a significant increase in the prevalence of blood vessels that stained for mEPCR and ICAM-1 in patients compared to controls [94% vs 59% (p = 0.045) and 81% vs 67% (p = 0.037), respectively]. Adiponectin staining and CD31 staining were similar between the groups (45% vs 43% and 98% vs 92%). Dermal staining for mEPCR was greater in patients with proliferative glomerulonephritis than in those with membranous disease (96% vs 60%; p = 0.029). A composite of poor prognostic renal markers and death was significantly associated with greater expression of mEPCR staining.

CONCLUSION

These data are consistent with the notion that in patients with LN, activation of the microvasculature extends beyond the clinically targeted organ. The insidious expression of this widespread vasculopathy may be a contributor to longterm comorbidities.

The interplay of inflammation and cardiovascular disease in systemic lupus erythematosus

Patients with systemic lupus erythematosus have up to a 50-fold increased risk of developing atherosclerotic cardiovascular disease. Recent advances in the etiology of vascular damage in this disease stress the interplay of lupus-specific inflammatory factors with traditional cardiac risk factors, leading to increased endothelial damage. This review analyzes the putative role that immune dysregulation and lupus-specific factors may play in the pathogenesis of premature vascular damage in this disease. The potential role of various cytokines, in particular type I interferons, in the development of accelerated atherosclerosis is examined. Potential therapeutic targets are discussed.