Use of Methylene Blue to Treat Hypovolemic Shock Followed by Ischemia-Reperfusion Injury in the Postoperative Orthotopic Liver Transplant Patient: A Case Report

Vasopressor-Sparing Action of Methylene Blue in Severe Sepsis and Shock: A Narrative Review

Shock is a serious acute circulatory failure leading to inadequate oxygen delivery to the cells. Its treatment is mainly based on circulating fluid optimization, and vasopressors to provide an adequate mean arterial pressure and microcirculatory flow. Norepinephrine is the drug of choice, but high dosages may be responsible for several side effects, including increased myocardial oxygen consumption, dysrhythmias, and peripheral and organ ischemia. Moreover, some patients are “non-responders” to first-line norepinephrine treatment. Hence, other drugs have been proposed to reach and maintain the hemodynamic target. In general, they are described as catecholamine-sparing agents. Among others, the most used are vasopressin, corticosteroids, and angiotensin II. Methylene blue (MB) represents a further option, even though its use is still a topic of controversy. This review article tries to summarize what is known and unknown about the actions of MB in patients in shock. It reduces excessive production of nitric oxide via blockade of guanylate cyclase in shock states. At present, it appears the MB provides positive results in septic shock, if administered early. Further randomized controlled trials are warranted regarding its use to provide more precise indications to physicians involved in the treatment of such patients.

N6-methyladenosine (m6A) methylation in ischemia-reperfusion injury

Ischemia-reperfusion (I/R) injury is common during surgery and often results in organ dysfunction. The mechanisms of I/R injury are complex, diverse, and not well understood. RNA methylation is a novel epigenetic modification that is involved in the regulation of various biological processes, such as immunity, response to DNA damage, tumorigenesis, metastasis, stem cell renewal, fat differentiation, circadian rhythms, cell development and differentiation, and cell division. Research on RNA modifications, specifically N6-methyladenosine (m6A), have confirmed that they are involved in the regulation of organ I/R injury. In this review, we summarized current understanding of the regulatory roles and significance of m6A RNA methylation in I/R injury in different organs.

Ischemia/Reperfusion Injury Revisited: An Overview of the Latest Pharmacological Strategies

Ischemia/reperfusion injury (IRI) permeates a variety of diseases and is a ubiquitous concern in every transplantation proceeding, from whole organs to modest grafts. Given its significance, efforts to evade the damaging effects of both ischemia and reperfusion are abundant in the literature and they consist of several strategies, such as applying pre-ischemic conditioning protocols, improving protection from preservation solutions, thus providing extended cold ischemia time and so on. In this review, we describe many of the latest pharmacological approaches that have been proven effective against IRI, while also revisiting well-established concepts and presenting recent pathophysiological findings in this ever-expanding field. A plethora of promising protocols has emerged in the last few years. They have been showing exciting results regarding protection against IRI by employing drugs that engage several strategies, such as modulating cell-surviving pathways, evading oxidative damage, physically protecting cell membrane integrity, and enhancing cell energetics.