Molecular imaging of cancer microenvironment / Imagen molecular del microentorno del cáncer

In the last decades, researchers have been focusing on cancer cells looking for novel targets, however, tumours grow in a host environment that either contribute to or inhibit tumour expansion and metastatization. Several efforts have been focused on cancer microenvironment for diagnostic and therapeutic purposes. Nuclear medicine can contribute to understand the complexity and role of tumour microenvironment by imaging several of its components (chemokine receptors, immune cells, stromal antigens, vascular factors, etc). In a tumour, each microenvironment component offers many potential targets for several drugs or radiopharmaceuticals. Cancer may be studied using different strategies from different viewpoints: imaging tumour markers or differentiating markers for diagnostic purposes in order to plan personalized therapies (receptor agonists or superagonists); imaging tumour stroma and vascularization to monitor cell adhesion, metastases, angiogenesis and hypoxia; imaging the host response of cancer cells to monitor efficacy of immunotherapeutic strategies

En las últimas décadas los investigadores han centrado su atención en la observación de las células cancerosas, en búsqueda de nuevos sitios blanco. Sin embargo, el crecimiento del tumor se produce en un entorno que, o inhibe, o contribuye a la expansión del tumor y su metástasis. Varios esfuerzos han estado enfocados al estudio del microentorno del cáncer, con propósitos diagnósticos o terapéuticos. La Medicina Nuclear puede contribuir a la comprensión de la complejidad y del papel que juega el microentorno del tumor, mediante la obtención de las imágenes de varios de sus componentes (receptores de quimioquinas, células inmunes, antígenos del estroma, factores vasculares, etc.). En un tumor, cada componente del microentorno ofrece muchos blancos potenciales para varias drogas o radiofármacos. El cáncer puede ser estudiado mediante diferentes estrategias y enfoques: mediante la imagen de marcadores tumorales, o la diferenciación de estos, con propósitos diagnósticos a fin de planificar terapias personalizadas (receptores agonistas o superagonistas); mediante la imagen del estroma del tumor y la vascularización, para monitorear la adhesión celular, la metástasis, la angiogénesis y la hipoxia; mediante la imagen de la respuesta del huésped de las células cancerosas, con el objetivo de monitorear la eficacia de las estrategias inmunoterapéuticas

Radiopharmaceuticals for imaging chronic lymphocytic inflammation

In the last few decades, a number of radiopharmaceuticals for imaging inflammation have been proposed that differ in their specificity and mechanism of uptake in inflamed foci as compared to the traditional inflammation imaging agents. Radiolabelled cytokines represent a reliable tool for the preclinical diagnosis of chronic inflammatory processes, even before anatomical and functional changes occur in affected tissues. Moreover, the introduction of radiolabelled monoclonal antibodies and sophisticated technique like PET/CT now make the field of inflammation imaging highly specific and accurate. In this review, different approaches of the established and experimental radiopharmaceuticals for imaging of chronic inflammation are discussed.

Nas últimas décadas, foram propostos vários radiofármacos para obtenção de imagens de sítios de inflamação, diferindo em suas especificidades e mecanismos de captação quando comparados aos tradicionais agentes utilizados para essa finalidade. Citocinas radiomarcadas representam uma ferramenta confiável para o diagnóstico pré-clinico precoce de processos inflamatórios crônicos, anterior às alterações anatômicas e funcionais, em tecidos afetados. Além disso, a introdução de anticorpos monoclonais radiomarcados e técnicas sofisticadas, como PET/CT, tornaram a obtenção de imagens de focos de inflamação altamente específica e apurada. Nesta revisão, diferentes abordagens com radiofármacos já bem estabelecidos e com outros em nível experimental para a obtenção de imagens de sítios de inflamação crônica são discutidas.

Radiolabelled cytokines for imaging chronic inflammation

Diagnosis and particularly follow-up of chronic inflammatory disorders could be often difficult in clinical practice. Indeed, traditional radiological techniques reveal only structural tissue alterations and are not able to monitor functional changes occurring in tissues affected by chronic inflammation. The continuous advances in the knowledge of the pathophysioloy of chronic disorders, combined with the progress of radiochemistry, led to the development of new specific radiolabelled agents for the imaging of chronic diseases. In this scenario, cytokines, due to their pivotal role in such diseases, represent good candidates as radiopharmaceuticals