Figure 4 shows a collaborative network diagram of authors with more than four publications, divided into five clusters overall, with Prof. Faiez Zannad at the center, working closely with 25 co-authors, including Patrick Rossignol and Bertram Pitt as his closest collaborators. Figure 4 highlights that the research group led by Prof. Patrick Rossignol has extensively studied the effects of spironolactone and other inhibitors of the renin-angiotensin-aldosterone system on heart failure patients over the past decade. The gene discussed is REN; the disease is heart failure.