Terapia génica: los ácidos nucleicos como fármacos: mecanismos de acción y vías de entrega a la célula / Gene therapy: nucleic acids as drugs: action mechanisms and delivery into the cell

La terapia génica involucra la transferencia de material genético a una célula para conseguir un beneficio terapéutico, por lo que ofrece una nueva opción para el tratamiento de muchas patologías. En este artículo se presentan algunos de los nuevos fármacos a base de ácidos nucleicos, como plásmidos, aptámeros, oligonucleótidos, ribozimas y pequeños ácidos ribonucleicos de interferencia. Se comenta el mecanismo y nivel de acción de estos agentes terapéuticos y se discuten sus varias vías de administración, como liposomas, polímeros catiónicos, transferencia directa de ácidos nucleicos y vectores virales.

Gene therapy involves the transference of new genetic material to the cell in order to obtain a therapeutic benefit, offering a new option for the treatment of various diseases. In this article, some of these nucleic acid-based drugs, such asplasmids, aptamers, oligonucleotides, ribozymes and small interfering ribonucleic acid, are presented. Their mechanism and level of action iscommented and several delivery systems, such as liposomes, cationic polymers, direct nucleic acid transfer and viral vectors, are also discussed.

Current and future treatment of hepatitis C.

Hepatitis C virus infection is a major health burden affecting an estimated 200 million people worldwide. Chronic hepatitis C is one of the leading causes of cirrhosis and end-stage liver cirrhosis; thus effective therapies are required. For many years interferon-alpha has been the treatment of choice for patients with chronic hepatitis C infection. However, in only 10%-15% of patients is interferon-alpha monotherapy successful, leading to sustained virological response. A combination of interferon-alpha and ribavirin significantly enhanced sustained virological response rates to 40%. Strategies to further improve response rates include modification of the interferon dosing schedule with induction dosing and daily interferon, new interferons such as consensus interferon, or interferon with longer half-life and more favorable pharmacokinetics such as pegylated interferons. Recent trials showed that a combination of pegylated interferons and ribavirin leads to sustained response rates of about 50% with an acceptable safety profile. Hopefully, new treatment modalities will be available in the near future. Helicase, protease and the RNA polymerase are potential targets to suppress HCV replication and several immunotherapeutic approaches are explored.