{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T13:43:33Z","timestamp":1790343813692,"version":"4.1.0"},"reference-count":48,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2020,11,27]],"date-time":"2020-11-27T00:00:00Z","timestamp":1606435200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Med."],"abstract":"<jats:p><jats:bold>Introduction:<\/jats:bold> Sepsis is a dysregulated host response to infection with macro- and microhemodynamic deterioration. Kynurenic acid (KYNA) is a metabolite of the kynurenine pathway of tryptophan catabolism with pleiotropic cell-protective effects under pro-inflammatory conditions. Our aim was to investigate whether exogenously administered KYNA or the synthetic analog SZR-72 affects the microcirculation and mitochondrial function in a clinically relevant rodent model of intraabdominal sepsis.<\/jats:p><jats:p><jats:bold>Methods:<\/jats:bold> Male Sprague\u2013Dawley rats (<jats:italic>n<\/jats:italic> = 8\/group) were subjected to fecal peritonitis (0.6 g kg<jats:sup>\u22121<\/jats:sup> feces ip) or a sham operation. Septic animals were treated with sterile saline or received ip KYNA or SZR-72 (160 \u03bcmol kg<jats:sup>\u22121<\/jats:sup> each) 16 and 22 h after induction. Invasive monitoring was performed on anesthetized animals to evaluate respiratory, cardiovascular, renal, hepatic and metabolic dysfunctions (PaO<jats:sub>2<\/jats:sub>\/FiO<jats:sub>2<\/jats:sub> ratio, mean arterial pressure, urea, AST\/ALT ratio and lactate levels, respectively) based on the Rat Organ Failure Assessment (ROFA) score. The ratio of perfused vessels (PPV) of the ileal serosa was quantified with the intravital imaging technique. Complex I- and II-linked (CI; CII) oxidative phosphorylation capacities (OXPHOS) and mitochondrial membrane potential (\u0394\u03a8mt) were evaluated by High-Resolution FluoRespirometry (O2k, Oroboros, Austria) in liver biopsies. Plasma endothelin-1 (ET-1), IL-6, intestinal nitrotyrosine (NT) and xanthine oxidoreductase (XOR) activities were measured as inflammatory markers.<\/jats:p><jats:p><jats:bold>Results:<\/jats:bold> Sepsis was characterized by an increased ROFA score (5.3 \u00b1 1.3 vs. 1.3 \u00b1 0.7), increased ET-1, IL-6, NT and XOR levels, and decreased serosal PPV (65 \u00b1 12% vs. 87 \u00b1 7%), \u0394\u03a8mt and CI\u2013CII-linked OXPHOS (73 \u00b1 16 vs. 158 \u00b1 14, and 189 \u00b1 67 vs. 328 \u00b1 81, respectively) as compared to controls. Both KYNA and SZR-72 reduced systemic inflammatory activation; KYNA treatment decreased serosal perfusion heterogeneity, restored PPV (85 \u00b1 11%) and complex II-linked OXPHOS (307 \u00b1 38), whereas SZR-72 improved both CI- and CII-linked OXPHOS (CI: 117 \u00b1 18; CII: 445 \u00b1 107) without effects on PPV 24 h after sepsis induction.<\/jats:p><jats:p><jats:bold>Conclusion:<\/jats:bold> Treatment with SZR-72 directly modulates mitochondrial respiration, leading to improved conversion of ADP to ATP, while administration of KYNA restores microcirculatory dysfunction. The results suggest that microcirculatory and mitochondrial resuscitation with KYNA or the synthetic analog SZR-72 might be an appropriate supportive tool in sepsis therapy.<\/jats:p>","DOI":"10.3389\/fmed.2020.566582","type":"journal-article","created":{"date-parts":[[2020,11,27]],"date-time":"2020-11-27T06:23:28Z","timestamp":1606458208000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":17,"title":["Divergent Effects of the N-Methyl-D-Aspartate Receptor Antagonist Kynurenic Acid and the Synthetic Analog SZR-72 on Microcirculatory and Mitochondrial Dysfunction in Experimental 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