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Aging is a complex process with an impact on essentially all organs. Declined cellular repair causes increased damage at genomic and proteomic levels upon aging. This can lead to systemic changes in metabolism and pro-inflammatory cytokine production, resulting in low-grade inflammation, or 'inflammaging'. Tissue macrophages, gatekeepers of parenchymal homeostasis and integrity, are prime inflammatory cytokine producers, as well as initiators and regulators of inflammation. In this opinion piece, we summarize intrinsic alterations in macrophage phenotype and function with age. We propose that alternatively activated macrophages (M2-like), which are yet pro-inflammatory, can accumulate in tissues and promote inflammaging. Age-related increases in endoplasmic reticulum stress and mitochondrial dysfunction might be cell-intrinsic forces driving this unusual phenotype. Highlights Aging is associated at the cellular level with several adaptations, fueled by increasing damage and reduced capacity for repair. This generates a condition of low-grade inflammation, called 'inflammaging'. Macrophages are prime cells in initiation and regulation of inflammatory processes and may thus play major roles in inflammaging. Macrophage polarization and activation, induced by intrinsic or extrinsic conditions, are reflected in and regulated by the cells' metabolic and epigenetic profiles. Age-induced changes in macrophages are diverse and, in general, may represent pro-inflammatory activation of cells with an alternatively activated (M2-like) phenotype. [ABSTRACT FROM AUTHOR]

Background In situ hypothermic perfusion during liver resection performed under vascular inflow occlusion decreases hepatic ischemia-reperfusion injury, but technical limitations have restricted its widespread use. In situ hypothermic perfusion with retrograde outflow circumvents these impediments and thus could extend the applicability of in situ hypothermic perfusion. The safety and feasibility of in situ hypothermic perfusion with retrograde outflow were analyzed in selected patients undergoing right (extended) hepatectomy and compared to intermittent vascular inflow occlusion, the gold standard method, in this randomized pilot study. Methods Patients were first screened for parenchymal liver disease (exclusion criteria: steatosis ≥30%, cirrhosis, or cholestasis). Study participants were randomized intraoperatively to undergo in situ hypothermic perfusion with retrograde outflow ( n = 9) or intermittent vascular inflow occlusion ( n = 9). The target liver core temperature during in situ hypothermic perfusion with retrograde outflow was 28°C. The primary end point was ischemia-reperfusion injury (expressed by peak postoperative transaminase levels). Secondary outcomes included functional liver regeneration (assessed by hepatobiliary scintigraphy) and clinical outcomes. Results Peak transaminase levels, total bilirubin, and the international normalized ratio were similar between both groups, although a trend toward more rapid normalization of bilirubin levels was noted for the in situ hypothermic perfusion with retrograde outflow group. Functional liver regeneration as evaluated by hepatobiliary scintigraphy was improved on postoperative day 3 fafter in situ hypothermic perfusion with retrograde outflow but not after intermittent vascular inflow occlusion. Furthermore, in situ hypothermic perfusion with retrograde outflow (requiring continuous ischemia) was comparable to intermittent vascular inflow occlusion for all clinical outcomes, including postoperative complications and hospital stay. Conclusion The use of in situ hypothermic perfusion with retrograde outflow appears to be safe and feasible in selected patients with healthy liver parenchyma and may benefit early functional liver regeneration. Future applications of in situ hypothermic perfusion with retrograde outflow include patients with damaged liver parenchyma who would require major hepatic resection with a prolonged vascular inflow occlusion duration. [ABSTRACT FROM AUTHOR]

Background Hepatic ischemia/reperfusion (I/R) injury is characterized by hepatocellular damage, sterile inflammation, and compromised postoperative liver function. Generally used mouse I/R models are too severe and poorly reflect the clinical injury profile. The aim was to establish a mouse I/R model with better translatability using hepatocellular injury, liver function, and innate immune parameters as endpoints. Methods Mice (C57Bl/6J) were subjected to sham surgery, 30 min, or 60 min of partial hepatic ischemia. Liver function was measured after 24 h using intravital microscopy and spectroscopy. Innate immune activity was assessed at 6 and 24 h of reperfusion using mRNA and cytokine arrays. Liver inflammation and function were profiled in two patient cohorts subjected to I/R during liver resection to validate the preclinical results. Results In mice, plasma ALT levels and the degree of hepatic necrosis were strongly correlated. Liver function was bound by a narrow damage threshold and was severely impaired following 60 min of ischemia. Severe ischemia (60 min) evoked a neutrophil-dominant immune response, whereas mild ischemia (30 min) triggered a monocyte-driven response. Clinical liver I/R did not compromise liver function and displayed a cytokine profile similar to the mild I/R injury model. Conclusions Mouse models using ≤ 30 min of ischemia best reflect the clinical liver I/R injury profile in terms of liver function dynamics and type of immune response. General significance This short duration of ischemia therefore has most translational value and should be used to increase the prospects of developing effective interventions for hepatic I/R. [ABSTRACT FROM AUTHOR]