Placebo in Surgical Research: A Case-Based Ethical Analysis and Practical Consequences.

Placebo is a form of simulated medical treatment intended to deceive the patient/subject who believes that he/she received an active therapy. In clinical medicine, the use of placebo is allowed in particular circumstances to assure a patient that he is taken care of and that he/she receives an active drug, even if this is not the case. In clinical research placebo is widely used, as it allows a baseline comparison for the active intervention. If the use of placebo is highly regulated in pharmacological trials, surgery studies have a series of particularities that make its use extremely problematic and regarded less favorably. The purpose of this paper is to present three famous cases of placebo use in surgical trials and to perform an ethical analysis of their acceptability using the Declaration of Helsinki as a main regulatory source.

Molecular signatures of cardiac stem cells.

The discovery of cardiac stem cells (CSCs) able to renew the pool of cardiomyocyte raised the question of how these cells can be recognized and directed towards cardiac reconstruction after severe ischemic injury. The functional studies demonstrated that the differentiation of adult cardiac stem cells reproduce the stages observed in the embryonic development. Each stage is characterized by a complex molecular signature, which can be used for identification and molecular targeting. Three major markers have been used to isolate CSCs: c-kit, Sca-1, and Isl1 and different progenitor populations have been described: side-population (SP), cardiosphere-derived, epicardial-derived. Combinations between the main three markers and other transcription factors, cell surface proteins and regulatory RNAs may delimit even further the cardiac precursors. Accumulation of data leads to the idea that a single, yet unidentified unique cardiac stem cell is at the origin of those observed variants. In this review, we intended to summarize the actual knowledge about the main molecular markers of cardiac stem cells.