Melanocortin peptides, the collective term for α-, β-, and γ-melanocyte-stimulating hormone (α-, β-, γ-MSH) and adrenocorticotropic hormone (ACTH), are elements of an ancient modulatory system. Natural melanocortins derive from the common precursor pro-opiomelanocortin (POMC). Five receptor subtypes for melanocortins (MC1-MC5) are widely distributed in brain regions and in peripheral cells. Melanocortin receptor activation by natural or synthetic ligands exerts marked anti-inflammatory and immunomodulatory effects. The anticytokine action and the inhibitory influences on inflammatory cell migration make melanocortins potential new drugs for treatment of inflammatory disorders. Effectiveness in treatment of acute, chronic, and systemic inflammatory disorders is well documented in preclinical studies. Further, melanocortins are promising compounds in neuroprotection. This review examines the main signaling circuits in anti-inflammatory and immunomodulatory actions of melanocortins, and the potential therapeutic use of these molecules.
In Italy, 20 minutes of a continuous flat line on an electrocardiogram are required for declaration of death. In the setting of donation after circulatory death (DCD), prolonged warm ischemia time prompted the introduction of abdominal normothermic regional perfusion (NRP) followed by postprocurement ex situ machine perfusion (MP). This is a retrospective review of DCD liver transplantations (LTs) performed at 2 centers using sequential NRP and ex situ MP. From January 2018 to April 2019, 34 DCD donors were evaluated. Three (8.8%) were discarded before NRP, and 11 (32.4%) were discarded based on NRP parameters (n = 1, 3.0%), liver macroscopic appearance at procurement and/or biopsy results (n = 9, 26.5%), or severe macroangiopathy at back‐table evaluation (n = 1, 3.0%). A total of 20 grafts (58.8%; 11 uncontrolled DCDs, 9 controlled DCDs) were considered eligible for LT, procured and perfused ex situ (9 normothermic and 11 dual hypothermic MPs). In total, 18 (52.9%; 11 uncontrolled) livers were eventually transplanted. Median (interquartile range) no‐flow time was 32.5 (30‐39) minutes, whereas median functional warm ischemia time was 52.5 (47‐74) minutes (controlled DCD), and median low‐flow time was 112 minutes (105‐129 minutes; uncontrolled DCD). There was no primary nonfunction, while postreperfusion syndrome occurred in 8 (44%) recipients. Early allograft dysfunction happened in 5 (28%) patients, while acute kidney injury occurred in 5 (28%). After a median follow‐up of 15.1 (9.5‐22.3) months, 1 case of ischemic‐type biliary lesions and 1 patient death were reported. DCD LT is feasible even with the 20‐minute no‐touch rule. Strict NRP and ex situ MP selection criteria are needed to optimize postoperative results.
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