Josep M. Grau

Rhabdomyolysis and Acute Kidney Injury

The causes of acute rhabdomyolysis include trauma, drugs, toxins, and certain infections. Acute kidney injury is a dangerous complication of severe rhabdomyolysis. This review summarizes current views on the pathogenesis of myoglobin-induced kidney injury as well as on its prevention and treatment.

Association between strong inflammatory response and low risk of developing visual loss and other cranial ischemic complications in giant cell (temporal) arteritis

OBJECTIVE To identify clinical and biochemical parameters that have good predictive value for identifying giant cell (temporal) arteritis (GCA) patients who are at high or low risk of developing cranial ischemic events. METHODS In this multicenter study, records of patients at 3 university hospitals in Barcelona were reviewed retrospectively. Two hundred consecutive patients with biopsy-proven GCA were studied. RESULTS Thirty-two patients developed irreversible cranial ischemic complications. The duration of clinical symptoms before diagnosis was similar in patients with and those without ischemic events. Patients with ischemic complications less frequently had fever (18.8% versus 56.9%) and weight loss (21.9% versus 62%) and more frequently had amaurosis fugax (32.3% versus 6%) and transient diplopia (15.6% versus 3.6%). Patients with ischemic events had lower erythrocyte sedimentation rates (ESR) (82.7 mm/hour versus 104.4 mm/hour) and higher concentrations of hemoglobin (12.2 gm/dl versus 10.9 gm/dl) and albumin (37.4 gm/liter versus 32.7 gm/liter). Clinical inflammatory status and biologic inflammatory status were defined empirically (clinical: fever and weight loss; biologic: ESR > or =85 mm/hour and hemoglobin < 11.0 gm/dl). Patients not showing a clinical and biologic inflammatory response were at high risk of developing ischemic events (odds ratio [OR] 5, 95% confidence interval [95% CI] 2.05-12.2). The risk was greatly reduced among patients with either a clinical (OR 0.177, 95% CI 0.052-0.605) or a biologic (OR 0.226, 95% CI 0.076-0.675) inflammatory reaction. No patient with both a clinical and a biologic response developed ischemic events. CONCLUSION The presence of a strong acute-phase response defines a subgroup of patients at very low risk of developing cranial ischemic complications. Our findings provide a rationale for testing less aggressive treatment schedules in these individuals. Conversely, a low inflammatory response and the presence of transient cranial ischemic events provide a high risk of developing irreversible ischemic complications and require a prompt therapeutic intervention.

Large vessel involvement in biopsy-proven giant cell arteritis: prospective study in 40 newly diagnosed patients using CT angiography

Background Necroscopic and surgical studies have suggested that giant cell arteritis (GCA) may target the aorta and its main branches. Imaging techniques are able to detect large vessel vasculitis (LVV) non-invasively in patients, but the prevalence of LVV in GCA has not been clearly established. Objective To assess prospectively the prevalence, characteristics and topography of LVV in patients with newly diagnosed GCA and to determine the associated clinical and laboratory features. Methods CT angiography (CTA) was performed in 40 consecutive patients with newly diagnosed biopsy-proven GCA. Patients were treatment-naïve or had been treated with corticosteroids for <3 days. Vessel wall thickness and vessel diameter (dilation or stenoses) at four aortic segments (ascending aorta, aortic arch, descending thoracic and abdominal aorta) and at the main aortic branches were evaluated. Results LVV was detected in 27 patients (67.5%). The vessels involved were as follows: aorta (26 patients, 65%), brachiocephalic trunk (19 patients, 47.5%), carotid arteries (14 patients, 35%), subclavian arteries (17 patients, 42.5%), axillary arteries (7 patients, 17.5%), splanchnic arteries (9 patients, 22.5%), renal arteries (3 patients, 7.5%), iliac arteries (6 patients, 15%) and femoral arteries (11 patients, 30%). Dilation of the thoracic aorta was already present in 6 patients (15%). Cranial ischaemic events were significantly less frequent in patients with LVV (p=0.029). Treatment-naïve patients had a higher frequency of LVV (77% vs 29%, p=0.005). Conclusions CTA-defined LVV occurs in two-thirds of patients with GCA at the time of diagnosis and aortic dilation is already present in 15%. Previous corticosteroid treatment may decrease CTA-detected LVV.

Elevated Production of Interleukin-6 Is Associated With a Lower Incidence of Disease-Related Ischemic Events in Patients With Giant-Cell Arteritis. Angiogenic Activity of Interleukin-6 as a Potential Protective Mechanism

Background—Patients with giant-cell arteritis (GCA) who develop a strong acute-phase response are at low risk of disease-related ischemic events. Methods and Results—To assess the potential protective role of proinflammatory cytokines in the development of ischemic events in GCA, we measured tissue expression (66 individuals) and/or circulating levels (80 individuals) of interleukin (IL)-1&bgr;, tumor necrosis factor-&agr; (TNF-&agr;), and IL-6 in patients with biopsy-proven GCA. Tissue expression was determined by quantitative real-time polymerase chain reaction and immunohistochemistry. Circulating cytokines were determined by enzyme-linked immunoassay. We found that patients with disease-related ischemic events had lower IL-6 mRNA levels (5.9±2.1 versus 27.6±7.8 relative units, P =0.013), lower IL-6 immunohistochemical expression scores (1.5±0.9 versus 2.7±1, P =0.001), and lower circulating levels of IL-6 (13.6±2.1 versus 24±2.4 pg/mL, P =0.002) than patients without ischemic complications. No significant differences were found for either IL-1&bgr; or TNF-&agr;. We subsequently investigated direct effects of IL-6 on vessel wall components. We found that IL-6 stimulates endothelial cell proliferation and differentiation into capillary-like structures and induces full angiogenic activity in both ex vivo (aortic ring) and in vivo (chick chorioallantoic membrane) assays. Conclusions—GCA patients with ischemic complications have lower tissue expression and circulating levels of IL-6 than patients with no ischemic events. IL-6 has relevant direct effects on vascular wall components that might be protective: IL-6 activates a functional program related to angiogenesis that may compensate for ischemia in patients with GCA.

Cell adhesion molecules in the development of inflammatory infiltrates in giant cell arteritis: Inflammation-induced angiogenesis as the preferential site of leukocyte–endothelial cell interactions

OBJECTIVE To investigate the expression pattern of adhesion molecules involved in leukocyte-endothelial cell interactions in giant cell arteritis (GCA). METHODS Immunohistochemical analysis was performed on frozen temporal artery sections from 32 patients with biopsy-proven GCA and from 12 control patients with other diseases. Adhesion molecules identified were intercellular adhesion molecule 1 (ICAM-1), ICAM-2, ICAM-3, vascular cell adhesion molecule 1 (VCAM-1), platelet endothelial cell adhesion molecule 1 (PECAM-1), E-selectin, P-selectin, L-selectin, lymphocyte function-associated antigen 1 (LFA-1), very late activation antigen 4 (VLA-4), Mac-1 (CD18/CD11b), and gp 150,95 (CD18/CD11c). Clinical and biochemical parameters of inflammation in the patients, as well as the duration of previous corticosteroid treatment, were prospectively recorded. RESULTS Constitutive (PECAM-1, ICAM-1, ICAM-2, and P-selectin) and inducible (E-selectin and VCAM-1) endothelial adhesion molecules for leukocytes were mainly expressed by adventitial microvessels and neovessels within inflammatory infiltrates. Concurrent analysis of leukocyte receptors indicated a preferential use of VLA-4/VCAM-1 and LFA-1/ICAM-1 at the adventitia and Mac-1/ICAM-1 at the intima-media junction. The intensity of inducible endothelial adhesion molecule expression (E-selectin and VCAM-1) correlated with the intensity of the systemic inflammatory response. Previous corticosteroid treatment reduced, but did not completely abrogate, the expression of the inducible endothelial adhesion molecules E-selectin and VCAM-1. CONCLUSION Inflammation-induced angiogenesis is the main site of leukocyte-endothelial cell interactions leading to the development of inflammatory infiltrates in GCA. The distribution of leukocyte-endothelial cell ligand pairs suggests a heterogeneity in leukocyte-endothelial cell interactions used by different functional cell subsets at distinct areas of the temporal artery.

Tissue and Serum Angiogenic Activity Is Associated With Low Prevalence of Ischemic Complications in Patients With Giant-Cell Arteritis

Background—Vascular inflammatory lesions from patients with giant-cell arteritis show a remarkable amount of neovascularization, but its clinical implications have never been investigated. Methods and Results—To assess the clinical relevance of neovascularization in giant-cell arteritis, angiogenesis was measured in temporal artery sections from 31 patients with biopsy-proven giant-cell arteritis by staining endothelial cells with Ulex europaeus lectin. Angiogenesis was highly variable among these patients. Patients without ischemic complications had higher tissue angiogenesis scores than patients with ischemic events (5.69±0.6 versus 2.91±0.6, P =0.003). Angiogenesis was also more prominent in patients with a strong acute phase response (score: 5.31±0.6) compared with those with a weak systemic inflammatory reaction (2.30±0.44;P =0.0007). Serum angiogenic activity was studied in an additional series of 38 biopsy-proven patients. Sera from patients without ischemic events tended to be more active in stimulating human umbilical vein endothelial cell growth (optical density ×1000, 270±15 versus 192±14, P =0.065) and differentiation into capillary-like structures (107±5 versus 84±8 relative units, P =0.0058) than patients with ischemic complications. Sera from patients without ischemic events had more in vivo full angiogenic activity tested in the chick chorioallantoic membrane than sera from patients with ischemic complications. Conclusion—Inflammation-induced angiogenic activity may play a compensatory role for ischemia in patients with giant-cell arteritis.

Positron emission tomography assessment of large vessel inflammation in patients with newly diagnosed, biopsy-proven giant cell arteritis: a prospective, case–control study

Background Positron emission tomography (PET) scan is emerging as a promising imaging technique to detect large-vessel inflammation in giant cell arteritis (GCA). However, the lack of a standardised definition of arteritis based on 18fluorodeoxyglucose (FDG) uptake is an important limitation to the use of PET scan for diagnostic purposes. Objective To prospectively assess the intensity and distribution of FDG uptake at different vascular territories in patients with newly diagnosed GCA compared with controls. Methods 32 consecutive, biopsy-proven, GCA patients treated with glucocorticoids for ≤3 days were included. The control group consisted of 20 individuals, who underwent PET/CT for cancer staging. Maximal standardised uptake value (SUVm) was calculated at four aortic segments, supraaortic branches and iliac-femoral territory. Sensitivity and specificity was calculated by receiver–operator characteristic curves (ROC) analysis. Results Mean SUVm was significantly higher in patients than in controls in all vessels explored and correlated with acute-phase reactants and serum IL-6. Mean of the SUVm at all the vascular territories had an area under the curve (AUC) of 0.830, and a cut-off of 1.89 yielded a sensitivity of 80% and a specificity of 79% for GCA diagnosis. There were no significant differences in AUC among the vascular beds examined. Conclusions FDG uptake by large vessels has a substantial sensitivity and specificity for GCA diagnosis.

Large vessel vasculitides.

During the past few years remarkable progress has been achieved in the understanding of the pathogenic mechanisms leading to vascular inflammation and injury in giant cell (temporal) arteritis. T lymphocytes are activated by specific recognition of a putative antigen residing in the arterial wall and, subsequently, activate macrophages that undergo a functional differentiation and contribute to vessel damage through various pathways. Vascular response to inflammation amplifies the inflammatory response through neovascularization and adhesion molecule expression. We are beginning to appreciate that products released by infiltrating inflammatory cells may play an important role in vessel occlusion and resulting ischemic complications. Concomitantly, synovitis underlying polymyalgia rheumatica musculoskeletal symptoms has been immunopathologically characterized and the nature of its relationship to giant cell arteritis is discussed. Although some components of the disease are highly corticosteroid responsive, other underlying pathogenic mechanisms may remain active. Long-term outcome is heterogeneous in patients with giant cell arteritis. Much less is known about the pathogenesis of Takayasus arteritis. Recent work supports its association with HLA class I antigens, which may differ in different geographic areas or ethnic groups. Because Takayasus disease expression may vary in different ethnic settings, this possibility has led to the proposal of new diagnostic criteria. Finally, the role of new imaging techniques in diagnosis and assessment of disease activity is discussed.

The geoepidemiology of autoimmune muscle disease.

Dermatomyositis (DM), polymyositis (PM), and sporadic inclusion-body myositis (sIBM) constitute a heterogeneous group of subacute or chronic acquired skeletal muscle diseases. Known as idiopathic inflammatory myopathies (IIM), they all share the presence of considerable weakness due to muscle inflammation and necrosis. Diagnosis is based on clinical findings, confirmed by laboratory examinations (serum muscle enzyme concentrations, autoantibodies against nuclear or cytoplasmatic antigens, electromyography, and muscle biopsy). Environmental exposures leading to immune activation in genetically susceptible individuals seem to be a probable pathogenic mechanism. Infectious agents, drugs, and ultraviolet radiation have been identified as a cause of the onset, exacerbation, or acceleration of these myopathies. Several case reports and population studies have been reported to support the relationship between inflammatory myopathy and the environment. Moreover, seasonal patterns of the onset of IIM have frequently been reported.

Small‐vessel vasculitis surrounding a spared temporal artery: Clinical and pathologic findings in a series of twenty‐eight patients

OBJECTIVE Occasionally, a temporal artery biopsy reveals small-vessel vasculitis (SVV) surrounding a spared temporal artery, the significance of which is unclear. We analyzed the final diagnosis in a series of patients with this condition and tried to identify histopathologic features with potential usefulness in predicting the ultimate diagnosis. METHODS We performed a clinical and histopathologic review of 28 patients in whom SVV surrounding a spared temporal artery was the first histologic finding that led to the diagnosis of vasculitis. For comparison purposes, we analyzed the pattern of small vessel involvement in 30 patients with biopsy-proven giant cell arteritis (GCA). RESULTS GCA was considered the most likely diagnosis in 12 patients, based on the absence of clinical evidence of additional organ involvement and normal findings on muscle biopsy and electrophysiologic study. Three patients had systemic necrotizing vasculitis (SNV), based on the demonstration of typical lesions on subsequent muscle, nerve, or kidney biopsy. After extensive evaluation, 4 patients remained unclassifiable. Nine patients were incompletely studied. Fibrinoid necrosis was significantly more frequent in patients with SNV (P = 0.0022), whereas involvement of vasa vasorum was more frequent in patients classified as having GCA (P = 0.022). No differences in the pattern of small vessel involvement were found in patients with SVV surrounding a spared temporal artery who were classified as having GCA compared with patients with biopsy-proven GCA. Granulocytes were observed at similar frequency in all conditions. CONCLUSION SVV may be the only abnormal feature in a temporal artery biopsy and the only histologic evidence of vasculitis. The diagnosis of GCA can be reasonably established in most of these patients when there is no apparent evidence of additional organ involvement. However, when fibrinoid necrosis is observed or the temporal artery vasa vasorum are not involved, SNV must be extensively excluded.