Alan Gorn
University of California, Los Angeles
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Alan Gorn.
Arthritis & Rheumatism | 2009
Maureen McMahon; Jennifer M. Grossman; Brian J. Skaggs; John FitzGerald; Lori Sahakian; Nagesh Ragavendra; Christina Charles-Schoeman; Karol E. Watson; Weng Kee Wong; Elizabeth R. Volkmann; Weiling Chen; Alan Gorn; George Karpouzas; Michael H. Weisman; Daniel J. Wallace; Bevra H. Hahn
OBJECTIVE Women with systemic lupus erythematosus (SLE) have an increased risk of atherosclerosis. Identification of at-risk patients and the etiology underlying atherosclerosis in SLE remain elusive. The antioxidant capacity of normal high-density lipoproteins (HDLs) is lost during inflammation, and these dysfunctional HDLs might predispose individuals to atherosclerosis. The aim of this study was to determine whether dysfunctional proinflammatory HDL (piHDL) is associated with subclinical atherosclerosis in SLE. METHODS Carotid artery ultrasound was performed in 276 women with SLE to identify carotid plaques and measure intima-media thickness (IMT). The antioxidant function of HDL was measured as the change in oxidation of low-density lipoprotein after the addition of HDL cholesterol. Two antiinflammatory HDL components, paraoxonase 1 and apolipoprotein A-I, were also measured. RESULTS Among the SLE patients, 48.2% were determined to have piHDL on carotid ultrasound, while 86.7% of patients with plaque had piHDL compared with 40.7% of those without plaque (P<0.001). Patients with piHDL also had a higher IMT (P<0.001). After multivariate analysis, the only factors found to be significantly associated with plaque were the presence of piHDL (odds ratio [OR] 16.1, P<0.001), older age (OR 1.2, P<0.001), hypertension (OR 3.0, P=0.04), dyslipidemia (OR 3.4, P=0.04), and mixed racial background (OR 8.3, P=0.04). Factors associated with IMT measurements in the highest quartile were the presence of piHDL (OR 2.5, P=0.02), older age (OR 1.1, P<0.001), a higher body mass index (OR 1.07, P=0.04), a cumulative lifetime prednisone dose>or=20 gm (OR 2.9, P=0.04), and African American race (OR 8.3, P=0.001). CONCLUSION Dysfunctional piHDL greatly increases the risk of developing subclinical atherosclerosis in SLE. The presence of piHDL was associated with an increased prevalence of carotid plaque and with a higher IMT. Therefore, determination of piHDL may help identify patients at risk for atherosclerosis.
Annals of the Rheumatic Diseases | 2011
Maureen McMahon; Brian J. Skaggs; Lori Sahakian; Jennifer Grossman; John P. Fitzgerald; Nagesh Ragavendra; Christina Charles-Schoeman; Marissa Chernishof; Alan Gorn; Joseph L. Witztum; Weng Kee Wong; Michael H. Weisman; Daniel J. Wallace; Antonio La Cava; Bevra H. Hahn
Background Patients with systemic lupus erythematosus (SLE) are at increased risk of atherosclerosis, even after accounting for traditional risk factors. High levels of leptin and low levels of adiponectin are associated with both atherosclerosis and immunomodulatory functions in the general population. Objective To examine the association between these adipokines and subclinical atherosclerosis in SLE, and also with other known inflammatory biomarkers of atherosclerosis. Methods Carotid ultrasonography was performed in 250 women with SLE and 122 controls. Plasma leptin and adiponectin levels were measured. Lipoprotein a (Lp(a)), oxidised phospholipids on apoB100 (OxPL/apoB100), paraoxonase, apoA-1 and inflammatory high-density lipoprotein (HDL) function were also assessed. Results Leptin levels were significantly higher in patients with SLE than in controls (23.7±28.0 vs 13.3±12.9 ng/ml, p<0.001). Leptin was also higher in the 43 patients with SLE with plaque than without plaque (36.4±32.3 vs 20.9±26.4 ng/ml, p=0.002). After multivariate analysis, the only significant factors associated with plaque in SLE were leptin levels in the highest quartile (≥29.5 ng/ml) (OR=2.8, p=0.03), proinflammatory HDL (piHDL) (OR=12.8, p<0.001), age (OR=1.1, p<0.001), tobacco use (OR=7.7, p=0.03) and hypertension (OR=3.0, p=0.01). Adiponectin levels were not significantly associated with plaque in our cohort. A significant correlation between leptin and piHDL function (p<0.001), Lp(a) (p=0.01) and OxPL/apoB100 (p=0.02) was also present. Conclusions High leptin levels greatly increase the risk of subclinical atherosclerosis in SLE, and are also associated with an increase in inflammatory biomarkers of atherosclerosis such as piHDL, Lp(a) and OxPL/apoB100. High leptin levels may help to identify patients with SLE at risk of atherosclerosis.
Arthritis Care and Research | 2010
Elizabeth R. Volkmann; Jennifer M. Grossman; Lori Sahakian; Brian J. Skaggs; John FitzGerald; Nagesh Ragavendra; Christina Charles-Schoeman; Weiling Chen; Alan Gorn; George Karpouzas; Michael H. Weisman; Daniel J. Wallace; Bevra H. Hahn; Maureen McMahon
To investigate the association between physical activity, functional activity of high‐density lipoprotein (HDL), and subclinical cardiovascular disease in patients with systemic lupus erythematosus (SLE).
Arthritis & Rheumatism | 2010
Rajeev Saggar; Dinesh Khanna; Daniel E. Furst; Shelley Shapiro; Paul Maranian; John A. Belperio; Neeraj Chauhan; Philip J. Clements; Alan Gorn; S. Sam Weigt; David J. Ross; Joseph P. Lynch; Rajan Saggar
OBJECTIVE Exercise-induced pulmonary hypertension (PH) may represent an early but clinically relevant phase in the spectrum of pulmonary vascular disease. There are limited data on the prevalence of exercise-induced PH determined by right heart catheterization in scleroderma spectrum disorders. We undertook this study to describe the hemodynamic response to exercise in a homogeneous population of patients with scleroderma spectrum disorders at risk of developing pulmonary vascular disease. METHODS Patients with normal resting hemodynamics underwent supine lower extremity exercise testing. A classification and regression tree (CART) analysis was used to assess combinations of variables collected during resting right heart catheterization that best predicted abnormal exercise physiology, applicable to each individual subject. RESULTS Fifty-seven patients who had normal resting hemodynamics underwent subsequent exercise right heart catheterization. Four distinct hemodynamic groups were identified during exercise: a normal group, an exercise-induced pulmonary venous hypertension (ePVH) group, an exercise out of proportion PH (eoPH) group, and an exercise-induced PH (ePH) group. The eoPH and ePVH groups had higher pulmonary capillary wedge pressure (PCWP) than the ePH group (P < 0.05). The normal and ePH groups had exercise PCWP ≤18 mm Hg, which was lower than that in the ePVH and eoPH groups (P < 0.05). During submaximal exercise, the transpulmonary gradient and pulmonary vascular resistance (PVR) were elevated in the ePH and eoPH groups as compared with the normal and ePVH groups (P < 0.05). CART analysis suggested that resting mean pulmonary artery pressure (mPAP) ≥14 mm Hg and PVR ≥160 dynes/seconds/cm(-5) were associated with eoPH and ePH (positive predictive value 89% for mPAP 14-20 mm Hg and 100% for mPAP >20 mm Hg). CONCLUSION We characterized the exercise hemodynamic response in at-risk patients with scleroderma spectrum disorders who did not have resting PH. Four distinct hemodynamic groups were identified during exercise. These groups may have potentially different prognoses and treatment options.
Arthritis & Rheumatism | 2014
Maureen McMahon; Brian J. Skaggs; Jennifer M. Grossman; Lori Sahakian; John FitzGerald; Weng Kee Wong; Elaine V. Lourenço; Nagesh Ragavendra; Christina Charles-Schoeman; Alan Gorn; George Karpouzas; Mihaela Taylor; Karol E. Watson; Michael H. Weisman; Daniel J. Wallace; Bevra H. Hahn
An increased frequency of atherosclerosis (ATH) in systemic lupus erythematosus (SLE) is well‐documented but not fully explained by the presence of traditional cardiac risk factors. Several nontraditional biomarkers, including proinflammatory high‐density lipoprotein (piHDL) and leptin, have been individually associated with subclinical ATH in SLE. The aim of this study was to examine whether these and other biomarkers can be combined into a risk profile, the Predictors of Risk for Elevated Flares, Damage Progression, and Increased Cardiovascular Disease in Patients with SLE (PREDICTS), that could be used to better predict future progression of ATH.
Arthritis & Rheumatism | 2013
Christina Charles-Schoeman; Yuen Yin Lee; Ani Shahbazian; Alan Gorn; John FitzGerald; Veena K. Ranganath; Mihaela Taylor; Nagesh Ragavendra; Maureen McMahon; David Elashoff; Srinivasa T. Reddy
OBJECTIVE To investigate the relationship of genetic and biochemical determinants of paraoxonase 1 activity to carotid plaque as a surrogate marker of cardiovascular (CV) risk in patients with rheumatoid arthritis (RA). METHODS The relationships between paraoxonase 1 activity, PON1 genotype (for the functional polymorphism at position 192), and carotid plaque presence were determined in 168 RA patients. After an overnight fast, blood was collected for lipoprotein analysis, and paraoxonase 1 activity was measured using paraoxon as the substrate. The PON1 Q192R genotype was determined for all patients. Lipoprotein cholesterol levels, traditional CV risk factors, medication use, and RA disease characteristics were assessed for all patients. RESULTS Paraoxonase 1 activity values in the RA patients were highest for the RR genotype, intermediate for the QR genotype, and lowest for the QQ genotype (P < 0.0001). Compared to patients with either the QQ genotype or the QR genotype, patients with the RR genotype demonstrated decreased risk of carotid plaque on multivariate analysis, controlling for traditional CV risk factors, high-sensitivity C-reactive protein levels, prednisone use, and cholesterol-lowering medication use (P < 0.05). Additional multivariate logistic regression analysis controlling for the above factors also revealed a significant association of plasma paraoxonase 1 activity with carotid plaque in RA patients. Lower plasma paraoxonase 1 activity was associated with increased risk of carotid plaque (P < 0.05). CONCLUSION The current findings suggest a relationship of the genetic determinants and activity of paraoxonase 1 to CV risk in RA patients, as assessed by the presence or absence of carotid plaque. Further CV outcome studies are warranted to validate the utility of paraoxonase 1 as a biomarker of CV risk in patients with RA.
Arthritis & Rheumatism | 2016
Elizabeth R. Volkmann; Yu-Ling Chang; Nashla Barroso; Daniel E. Furst; Philip J. Clements; Alan Gorn; Bennett E. Roth; Jeffrey L. Conklin; Terri Getzug; James Borneman; Dermot P. McGovern; Maomeng Tong; Jonathan P. Jacobs; Jonathan Braun
To compare colonic microbial composition in systemic sclerosis (SSc) patients and healthy controls and to determine whether certain microbial genera are associated with gastrointestinal (GI) tract symptoms in patients with SSc.
Arthritis & Rheumatism | 2016
Elizabeth R. Volkmann; Yu-Ling Chang; Nashla Barroso; Daniel E. Furst; Philip P. Clements; Alan Gorn; Bennett E. Roth; Jeffrey L. Conklin; Terri Getzug; James Borneman; Dermot P. McGovern; Maomeng Tong; Jonathan P. Jacobs; Jonathan Braun
To compare colonic microbial composition in systemic sclerosis (SSc) patients and healthy controls and to determine whether certain microbial genera are associated with gastrointestinal (GI) tract symptoms in patients with SSc.
Arthritis & Rheumatism | 2006
Xuebing Feng; Hui Wu; Jennifer M. Grossman; Punchong Hanvivadhanakul; John FitzGerald; Grace S. Park; Xin Dong; Weiling Chen; Michelle H. Kim; Haoling H. Weng; Daniel E. Furst; Alan Gorn; Maureen McMahon; Mihaela Taylor; Ernest Brahn; Bevra H. Hahn; Betty P. Tsao
Jcr-journal of Clinical Rheumatology | 2004
Kathy Karamlou; Alan Gorn