Electrophilic PPAR[gamma] ligands inhibit corneal fibroblast to myofibroblast differentiation in vitro: A potentially novel therapy for corneal scarring

A critical component of corneal scarring is the TGF[beta]-induced differentiation of corneal keratocytes into myofibroblasts. Inhibitors of this differentiation are potentially therapeutic for corneal scarring. In this study, we tested the relative effectiveness and mechanisms of action of two electrophilic peroxisome proliferator-activated receptor gamma (PPAR[gamma]) ligands: cyano-3,12-dioxolean-1,9-dien-28-oic acid-methyl ester (CDDO-Me) and 15-deoxy-[DELTA].sup.-12,14-prostaglandin J.sub.2 (15d-PGJ.sub.2) for inhibiting TGF[beta]-induced myofibroblast differentiation in vitro. TGF[beta] was used to induce myofibroblast differentiation in cultured, primary human corneal fibroblasts. CDDO-Me and 15d-PGJ.sub.2 were added to cultures to test their ability to inhibit this process. Myofibroblast differentiation was assessed by measuring the expression of myofibroblast-specific proteins ([alpha]SMA, collagen I, and fibronectin) and mRNA ([alpha]SMA and collagen III). The role of PPAR[gamma] in the inhibition of myofibroblast differentiation by these agents was tested in genetically and pharmacologically manipulated cells. Finally, we assayed the importance of electrophilicity in the actions of these agents on TGF[beta]-induced [alpha]SMA expression via Western blotting and immunofluorescence. Both electrophilic PPAR[gamma] ligands (CDDO-Me and 15d-PGJ.sub.2) potently inhibited TGF[beta]-induced myofibroblast differentiation, but PPAR[gamma] was only partially required for inhibition of myofibroblast differentiation by either agent. Electrophilic PPAR[gamma] ligands were able to inhibit myofibroblast differentiation more potently than non-electrophilic PPAR[gamma] ligands, suggesting an important role of electrophilicity in this process. CDDO-Me and 15d-PGJ.sub.2 are strong inhibitors of TGF[beta]-induced corneal fibroblast to myofibroblast differentiation in vitro, suggesting this class of agents as potential novel therapies for corneal scarring warranting further study in pre-clinical animal models.Academi

Electrophilic PPARγ ligands inhibit corneal fibroblast to myofibroblast differentiation in vitro: A potentially novel therapy for corneal scarring

A critical component of corneal scarring is the TGFβ-induced differentiation of corneal keratocytes into myofibroblasts. Inhibitors of this differentiation are potentially therapeutic for corneal scarring. In this study, we tested the relative effectiveness and mechanisms of action of two electrophilic peroxisome proliferator-activated receptor gamma (PPARγ) ligands: cyano-3,12-dioxolean-1,9-dien-28-oic acid-metheyl ester (CDDO-Me) and 15-deoxy-Δ-12,14-prostaglandin J(2) (15d-PGJ(2)) for inhibiting TGFβ-induced myofibroblast differentiation in vitro. TGFβ was used to induce myofibroblast differentiation in cultured, primary human corneal fibroblasts. CDDO-Me and 15d-PGJ(2) were added to cultures to test their ability to inhibit this process. Myofibroblast differentiation was assessed by measuring the expression of myofibroblast-specific proteins (αSMA, collagen I, and fibronectin) and mRNA (αSMA and collagen III). The role of PPARγ in the inhibition of myofibroblast differentiation by these agents was tested in genetically and pharmacologically manipulated cells. Finally, we assayed the importance of electrophilicity in the actions of these agents on TGFβ-induced αSMA expression via Western blotting and immunofluorescence. Both electrophilic PPARγ ligands (CDDO-Me and 15d-PGJ(2)) potently inhibited TGFβ-induced myofibroblast differentiation, but PPARγ was only partially required for inhibition of myofibroblast differentiation by either agent. Electrophilic PPARγ ligands were able to inhibit myofibroblast differentiation more potently than non-electrophilic PPARγ ligands, suggesting an important role of electrophilicity in this process. CDDO-Me and 15d-PGJ(2) are strong inhibitors of TGFβ-induced corneal fibroblast to myofibroblast differentiation in vitro, suggesting this class of agents as potential novel therapies for corneal scarring warranting further study in pre-clinical animal models

Hepatitis C viral load does not predict disease outcome: going beyond numbers A carga viral do vírus da hepatite C não prediz a evolução: indo além dos números

The analysis of 58 patients with chronic hepatitis C without cirrhosis and treated with interferon-alpha demonstrated that hepatitis C viral (HCV) load does not correlate with the histological evolution of the disease (p = 0.6559 for architectural alterations and p = 0.6271 for the histological activity index). Therefore, the use of viral RNA quantification as an evolutive predictor or determinant of the severity of hepatitis C is incorrect and of relative value. A review of the literature provided fundamental and interdependent HCV (genotype, heterogeneity and mutants, specific proteins), host (sex, age, weight, etc) and treatment variables (dosage, time of treatment, type of interferon) within the broader context of viral kinetics, interferon-mediated immunological response (in addition to natural immunity against HCV) and the role of interferon as a modulator of fibrogenesis. Therefore, viral load implies much more than numbers and the correct interpretation of these data should consider a broader context depending on multiple factors that are more complex than the simple value obtained upon quantification.<br>Através da análise de 58 pacientes tratados com Interferon Alfa em função de hepatite C crônica e sem cirrose, demonstramos que a carga viral do Vírus da Hepatite C (VHC) não se correlacionou com a evolução histológica da doença (p = 0,6559 para alterações arquiteturais e p = 0,6271 para o Índice de Atividade Histológica-IAH). Assim a utilização da quantificação do RNA viral como preditor evolutivo ou determinante da gravidade da hepatite C é incorreto e de valor relativo. Revisando o tema encontramos variáveis do VHC (genótipo, heterogeneidade e mutantes, proteínas específicas), do hospedeiro (sexo, idade, peso, etc) e dos medicamentos (posologia, tempo de tratamento, tipo de Interferon) fundamentais e interdependentes, inseridas no contexto mais amplo da cinética viral, da resposta imunológica mediada pelo Interferon (além da imunidade natural em resposta ao VHC) e do papel do Interferon como modulador da fibrogênese. Assim, há muito mais que números por trás da Carga Viral e sua correta interpretação deve ser feita considerando-se um horizonte mais amplo dependente de múltiplos fatores mais complexos que o simples valor obtido na quantificaçã