Loreto Massardo
Pontifical Catholic University of Chile
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Loreto Massardo.
Journal of Experimental Medicine | 2007
Soledad Matus; Patricia V. Burgos; Marcela Bravo-Zehnder; Regine Kraft; Omar H. Porras; Paula Farías; L. Felipe Barros; Fernando Torrealba; Loreto Massardo; Sergio Jacobelli; Alfonso González
The interesting observation was made 20 years ago that psychotic manifestations in patients with systemic lupus erythematosus are associated with the production of antiribosomal-P protein (anti-P) autoantibodies. Since then, the pathogenic role of anti-P antibodies has attracted considerable attention, giving rise to long-term controversies as evidence has either contradicted or confirmed their clinical association with lupus psychosis. Furthermore, a plausible mechanism supporting an anti-P–mediated neuronal dysfunction is still lacking. We show that anti-P antibodies recognize a new integral membrane protein of the neuronal cell surface. In the brain, this neuronal surface P antigen (NSPA) is preferentially distributed in areas involved in memory, cognition, and emotion. When added to brain cellular cultures, anti-P antibodies caused a rapid and sustained increase in calcium influx in neurons, resulting in apoptotic cell death. In contrast, astrocytes, which do not express NSPA, were not affected. Injection of anti-P antibodies into the brain of living rats also triggered neuronal death by apoptosis. These results demonstrate a neuropathogenic potential of anti-P antibodies and contribute a mechanistic basis for psychiatric lupus. They also provide a molecular target for future exploration of this and other psychiatric diseases.
Arthritis & Rheumatism | 2010
Samuel Katsuyuki Shinjo; Eloisa Bonfa; Daniel Wojdyla; Eduardo Ferreira Borba; Luis Alberto Ramírez; Hugo R. Scherbarth; João Carlos Tavares Brenol; Rosa Chacón-Diaz; Oscar Neira; Guillermo A. Berbotto; Ignacio García-De La Torre; Eduardo M. Acevedo-Vázquez; Loreto Massardo; Leonor Barile-Fabris; Francisco Caeiro; Luis H. Silveira; Emilia Inoue Sato; Sandra Buliubasich; Graciela S. Alarcón; Bernardo A. Pons-Estel
OBJECTIVE To evaluate the beneficial effect of antimalarial treatment on lupus survival in a large, multiethnic, international longitudinal inception cohort. METHODS Socioeconomic and demographic characteristics, clinical manifestations, classification criteria, laboratory findings, and treatment variables were examined in patients with systemic lupus erythematosus (SLE) from the Grupo Latino Americano de Estudio del Lupus Eritematoso (GLADEL) cohort. The diagnosis of SLE, according to the American College of Rheumatology criteria, was assessed within 2 years of cohort entry. Cause of death was classified as active disease, infection, cardiovascular complications, thrombosis, malignancy, or other cause. Patients were subdivided by antimalarial use, grouped according to those who had received antimalarial drugs for at least 6 consecutive months (user) and those who had received antimalarial drugs for <6 consecutive months or who had never received antimalarial drugs (nonuser). RESULTS Of the 1,480 patients included in the GLADEL cohort, 1,141 (77%) were considered antimalarial users, with a mean duration of drug exposure of 48.5 months (range 6-98 months). Death occurred in 89 patients (6.0%). A lower mortality rate was observed in antimalarial users compared with nonusers (4.4% versus 11.5%; P< 0.001). Seventy patients (6.1%) had received antimalarial drugs for 6-11 months, 146 (12.8%) for 1-2 years, and 925 (81.1%) for >2 years. Mortality rates among users by duration of antimalarial treatment (per 1,000 person-months of followup) were 3.85 (95% confidence interval [95% CI] 1.41-8.37), 2.7 (95% CI 1.41-4.76), and 0.54 (95% CI 0.37-0.77), respectively, while for nonusers, the mortality rate was 3.07 (95% CI 2.18-4.20) (P for trend < 0.001). After adjustment for potential confounders in a Cox regression model, antimalarial use was associated with a 38% reduction in the mortality rate (hazard ratio 0.62, 95% CI 0.39-0.99). CONCLUSION Antimalarial drugs were shown to have a protective effect, possibly in a time-dependent manner, on SLE survival. These results suggest that the use of antimalarial treatment should be recommended for patients with lupus.
Lupus | 2011
E Jarpa; M Babul; J Calderón; M González; Me Martínez; M Bravo-Zehnder; C Henríquez; Sergio Jacobelli; Alfonso González; Loreto Massardo
Psychiatric diagnosis in patients with systemic lupus erythematosus (SLE) is controversial: variations have been reported in frequency, diagnostic assays, associations with disease activity, autoantibodies, and contributing social factors. Eighty-three consecutive non-selected Chilean patients with SLE were evaluated for: (i) 26 common mental disorders according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), using the Mini-International Neuropsychiatric Interview (MINI-plus); (ii) psychological suffering measured by Hospital Anxiety and Depression Scale (HADS); (iii) ACR 1999 neuropsychiatric (NP)SLE criteria; (iv) SLE disease activity (SLEDAI-2K); (v) cumulative damage (SLICC/ACR); and (vi) anti-ribosomal P antibodies by enzyme-linked immunoassay and immunoblot. Psychiatric diagnoses occurred in 44.6% of patients; the most frequent (21.7%) was major depressive episode (MDE). No association with lupus activity was observed in patients with a DSM-IV diagnosis or MDE or psychological suffering. ACR 1999 NPSLE criteria were present in 42.2% of patients, the majority corresponding to mood (28.9%) or anxiety disorders (15.6%). Suicidal risk was present in 9.6% of patients. Anti-ribosomal P antibodies (13.3%) were not associated with DSM-IV diagnosis. Severe psychiatric disorders in SLE are common and not associated with disease activity.
Arthritis Care and Research | 2012
Loreto Massardo; Bernardo A. Pons-Estel; Daniel Wojdyla; Mario H. Cardiel; Claudio Galarza-Maldonado; Mónica P. Sacnun; Enrique R. Soriano; Ieda Maria Magalhães Laurindo; Eduardo M. Acevedo-Vásquez; Carlo V. Caballero-Uribe; Oslando Padilla; Zoila M. Guibert‐Toledano; Licia Maria Henrique da Mota; Rubén Montúfar; Leticia Lino-Pérez; José Francisco Díaz-Coto; Angel F. Achurra‐Castillo; Jaime Hernández; María H Esteva-Spinetti; Luis Alberto Ramírez; Carlos Pineda; Daniel E. Furst
To determine the influence of socioeconomic factors on disease activity in a Latin American (LA) early rheumatoid arthritis (RA) multinational inception cohort at baseline.
Lupus | 2002
Loreto Massardo; P Burgos; M E Martínez; R Pérez; M Calvo; J Barros; A González; Sergio Jacobelli
The objective of this work was to determine the frequency and clinical associations of antiribosomal P protein antibodies (Anti-P) in a cohort of Chilean patients with systemic lupus erythematosus (SLE). Between 1996 and 1998, 141 consecutive patients with SLE were examined prospectivelyaccording with a standard protocol. Disease activity was measured by MEX-SLEDAI in 138 patients. Anti-P positivity was determined by double immune diffusion or Western blot and ELISA. Anti-P was found in 21 (15%) patients. In the Anti-P positive patients recent onset SLE (disease duration of 1 year or less) was more frequent (P=0.018). Anti-P was found in 23% of 83 patients with active SLE vs 4% of the 55 patients with inactive SLE (Yates corrected P=0.00479). An association with anti-dsDNA antibodies by Farr assay was observed. Anti-P positive patients had a median Farr of 65 IU/ml (1.4–1240) and Anti-P negative of 12 IU/ml (1.4–992; P-value=0.0084). During the study only two patients had lupus psychosis and they were Anti-P positive. No association was found with liver disease (six patients, two with Anti-P antibodies) or active glomerulonephritis(22 patients, four with Anti-P). Our data shows that the presence of Anti-P antibodies supports the clinical diagnosis of lupus psychosis.
Seminars in Arthritis and Rheumatism | 1995
Loreto Massardo; Verónica Aguirre; M. Eugenia García; Vinicio Cervilla; Sandra Nicovani; Alfonso González; Santiago Rivero; Sergio Jacobelli
In populations such as Northern Europeans in which the HLA-DR4 subtypes DW14 and Dw4 show strong association with rheumatoid arthritis (RA), these alleles and the double allelic dose of the shared epitope are considered severity markers. The clinical expression of RA varies in different populations, which may be determined by variation in the prevalence of these markers. In the present study we analyzed the expression of RA in 112 consecutive Chilean patients and its relation to the prevalence of genetic factors, prompted by our previous observation that DR4 is weakly associated to RA in this population. Mean age was 50 +/- 14 years; 90% were seropositive and 87% were female, with a disease duration of 10 +/- 8 years. Extra-articular manifestations were found in 38% of patients, rheumatoid nodules in 27%, vasculitis in 8%, and Sjogrens syndrome in 29%. Functional capacity (ACR, 1991) I or II: 82%.15% of patients stopped working. Hand radiographs scored according to Steinbrocker in 89 patients: I, 21%; II, 15%; III, 43%; IV, 21%. In this series, patients with less formal education seemed to have more benign arthritis. In 97 controls and in 65 (56%) RA patients the presence of DRB1 alleles corresponding to DR1 and DR4 serotypes, to DR4-Dw subtypes, and homozygocity, were determined by polymerase chain reaction followed by specific oligonucleotide hybridization. The shared epitope was present in 53% of RA patients and in 30% of controls (P = .0048, odds ratio [OR] = 2.64). A double allelic dose of the epitope was present in 15% of RA patients compared with 4% of controls (P = .026, OR = 4.23). In a subgroup of 31 erosive RA patients we did not find a significant association of disease severity with the shared epitope in a single or double allelic dose. None of the DR4 subtypes that associate with RA in other populations was found significantly more prevalent in our patients. The severity of RA in our study compared with published series was intermediate between British patients with severe RA and Greek patients with milder disease. This may be due to the high prevalence of Dwl3*0403 in our population.
Arthritis & Rheumatism | 2015
Marcela Bravo-Zehnder; Enrique M. Toledo; Fabián Segovia-Miranda; Felipe G. Serrano; Maria J. Benito; Claudia Metz; Claudio Retamal; Alejandra R. Alvarez; Loreto Massardo; Nibaldo C. Inestrosa; Alfonso González
To define whether anti‐ribosomal P (anti‐P) autoantibodies from patients with neuropsychiatric systemic lupus erythematosus (NPSLE) impair the function of hippocampal neurons that express the neuronal surface P antigen (NSPA) when accessing the brain via circulating blood.
Journal of Biological Chemistry | 2009
Andrés Norambuena; Claudia Metz; Lucas Vicuña; Antonia Silva; Evelyn Pardo; Claudia Oyanadel; Loreto Massardo; Alfonso González; Andrea Soza
Galectins have been implicated in T cell homeostasis playing complementary pro-apoptotic roles. Here we show that galectin-8 (Gal-8) is a potent pro-apoptotic agent in Jurkat T cells inducing a complex phospholipase D/phosphatidic acid signaling pathway that has not been reported for any galectin before. Gal-8 increases phosphatidic signaling, which enhances the activity of both ERK1/2 and type 4 phosphodiesterases (PDE4), with a subsequent decrease in basal protein kinase A activity. Strikingly, rolipram inhibition of PDE4 decreases ERK1/2 activity. Thus Gal-8-induced PDE4 activation releases a negative influence of cAMP/protein kinase A on ERK1/2. The resulting strong ERK1/2 activation leads to expression of the death factor Fas ligand and caspase-mediated apoptosis. Several conditions that decrease ERK1/2 activity also decrease apoptosis, such as anti-Fas ligand blocking antibodies. In addition, experiments with freshly isolated human peripheral blood mononuclear cells, previously stimulated with anti-CD3 and anti-CD28, show that Gal-8 is pro-apoptotic on activated T cells, most likely on a subpopulation of them. Anti-Gal-8 autoantibodies from patients with systemic lupus erythematosus block the apoptotic effect of Gal-8. These results implicate Gal-8 as a novel T cell suppressive factor, which can be counterbalanced by function-blocking autoantibodies in autoimmunity.
Jcr-journal of Clinical Rheumatology | 2009
Loreto Massardo; María E. Suárez-Almazor; Mario H. Cardiel; Arnulfo Nava; Roger A. Levy; Ieda Maria Magalhães Laurindo; Enrique R. Soriano; Eduardo Acevedo-Vázquez; Alberto Millán; Carlos Pineda-Villaseñor; Claudio Galarza-Maldonado; Carlo V. Caballero-Uribe; Rolando Espinosa-Morales; Bernardo A. Pons-Estel
Objective:A consensus meeting of representatives of 18 Latin-American and Caribbean countries gathered in Reñaca, Chile, for 2 days to identify problems and provide recommendations for the care of patients with rheumatoid arthritis (RA) in Latin America, a region where poverty and other health priorities make the efforts to provide effective and high quality care difficult. This report includes recommendations for health professionals, patients, and health authorities in Latin America, with an emphasis on education and therapeutic issues. Methods:Fifty-one rheumatologists (list available only online on the JCR website) from 18 Latin-American and Caribbean countries with a special interest in RA participated in the consensus meeting. Participants were experts identified and appointed by the National Societies of Rheumatology affiliated with the Pan-American League of Associations for Rheumatology (PANLAR) and by the Grupo Latino Americano De Estudio de Artritis Reumatoide (GLADAR)—an independent group of Latin American rheumatologist researchers were also invited to the meeting. Eight topics were identified as priorities: patient, community and allied health professional education, health policy and decision making, programs for early detection and appropriate treatment of RA, role of classic disease modifying antirheumatic drugs (DMARDs), role of biologic therapy, and drug safety surveillance. To reach consensus, a survey with questions relevant to the topic of interest was sent to all participants before the meeting. During a 2 day meeting, the answers of the survey were reviewed and discussed by each group, with final recommendations on action items. Results:The specific topic of the survey was answered by 86% of the participants and 68% of them answered the entire survey. It was agreed that RA and rheumatic diseases which are currently not but should be public health priorities in Latin America, because of their prevalence and impact on quality of life. Conclusions:Strategic areas identified as priorities for our region included: early diagnosis and access to care by multidisciplinary teams, creation of databases to identify infections with the use of biologic agents in RA which are relevant to Latin America, and overall efforts to improve the care of RA patients in accordance with international standards. Implementation of educational programs aimed to improve self-management for patients with RA was also considered crucial.
Annals of the Rheumatic Diseases | 1997
Alfonso González; Sandra Nicovani; Loreto Massardo; Verónica Aguirre; Vinicio Cervilla; Jerry S Lanchbury; Sergio Jacobelli
OBJECTIVE To analyse the influence of shared epitope positive HLA-DRB1 alleles (QKRAA or QRRAA) ) on rheumatoid arthritis (RA) susceptibility and severity in Chileans, a population that exhibits a weak association with HLA-DR4. METHODS Prevalence of alleles DRB1*01 and DRB1*04 alleles was determined by polymerase chain reaction amplification and sequence specific oligonucleotide hybridisation in 129 RA patients with defined clinical features and in 97 healthy controls. RESULTS The shared epitope was found in 70 (54%) of the RA patients and in 29 (30%) of controls (odds ratio (OR) =3; 95% confidence intervals (CI) = 1.5, 5.1; p = 0.0004), and was present in a double dose in 20% of patients versus 4% of controls (OR = 6; 95% CI = 2, 21; p = 0.0009). HLA-DRB1*0403 was the most prevalent DR4 subtype in controls (19%). HLA-DRB1*0404 or *0408 were the alleles most prominently associated with RA, 19% versus 6 % in controls (OR=3; 95% CI = 1.3, 10; p = 0.01). The risk of RA in those carrying a double dose of the shared epitope was 7.5 times that seen in patients lacking the epitope. Disease severity was moderate: 33% had extra-articular manifestations. The double dose was associated with an increased risk of vasculitis or extra-articular manifestations. However, 59 patients (46%) did not carry the shared epitope and 18 of them (31%) had extra-articular manifestations. CONCLUSIONS The weak association of RA with DR4 in Chileans seems to relate to a relatively high frequency of the DRB1*0403 allele among DR4 subtypes. As in other populations, the shared epitope in double dose is associated with RA development, especially in its more severe forms. However, both development and expression of severe forms of the disease were independent of the shared epitope in a high proportion of patients, thus emphasising the genetic heterogeneity of the disease and the possible involvement of other genetic elements.