Cardiovascular diseases are conditions pertaining to the heart /vessels that carry blood. According to the WHO, around 30,000 individuals die every day because of cardiovascular disease (CVD). In 2016, CVD was the reason for almost 15. 2 million mortalities globally [1], [2]. People all around the world became more attentive about how to reduce heart diseases and other illnesses that cannot be passed from one person to another [3], [4]. Regardless of significant improvements in identifying and treating cardiovascular diseases, these still continue to be the main reason for people dying worldwide [5].

miR-155 is a small piece of nc RNA that is made up of about 20 building blocks and is produced by B-cell group stimulating gene. It can be found in many different types of blood cells [6]. There is more and more indications showing that miR-155 is a significant controller of cell balance and has many functions. It can affect different pathways in the body, including those related to heart problems and other health issues [7], [8]. Furthermore, the amounts of miR-155 in the blood were about four times higher in people who died due to heart condition within a year after leaving the hospital, in comparison to those who did not have heart problems [9].

Exosomes are tiny envelopes that are released from different cells and can be found in many bodily liquids [10]. Exosomes have lots of tiny molecules from one cell that can be transferred to another cell. These molecules can include small bits of genetic material, proteins, or even organelles [11], [12]. A lot of research has been done on how tiny particles called EVs and the genetic material they carry (microRNA), can help detect and recognize heart disease [13], [14]. Moreover, it was shown that exosomes containing microRNA-155, which come from macrophages, are able to control the characteristics of fibroblasts while the heart is damaged [15]. Herein the role of miR-155 and its exosomal form in Heart diseases are summarized.