Colectomy in patients with liver disease: albumin-bilirubin score accurately predicts outcomes.

BACKGROUND: Patients with liver disease undergoing colectomy have higher rates of complications and mortality. The Albumin-Bilirubin score is a recently developed system, established to predict outcomes after hepatectomy, that accounts for liver dysfunction. METHODS: All patients undergoing colectomy were identified in the 2015-2018 American College of Surgeons National Surgical Quality Improvement Program colectomy-targeted database. Demographics and outcomes were compared between patients with Albumin-Bilirubin Grade 1 vs. 2/3. Multivariable regression was performed for outcomes including colorectal-specific complications. Areas under the receiver operative characteristic curves were calculated to determine accuracy of the Albumin-Bilirubin score. RESULTS: Of 86,273 patients identified, 48% (N = 41,624) were Albumin-Bilirubin Grade 1, 45% (N = 38,370) Grade 2 and 7% (N = 6,279) Grade 3. Patents with Grade 2/3 compared to Grade 1 had significantly increased mortality (7.2% vs. 0.9%, p < 0.001) and serious morbidity (31% vs. 12%, p < 0.001). Colorectal-specific complications including anastomotic leak (3.7% vs. 2.8%, p < 0.001) and prolonged ileus (26% vs. 14%, p < 0.001) were higher in patients with Grade 2/3. Grade 2/3 had increased risk of mortality (odds ratio 3.07, p < 0.001) and serious morbidity (1.78, p < 0.001). Albumin-Bilirubin had excellent accuracy in predicting mortality (area under the curve 0.81, p < 0.001) and serious morbidity (0.70, p < 0.001). CONCLUSION: Albumin-Bilirubin is easily calculated using only serum albumin and total bilirubin values. Grade 2/3 is associated with increased rates of mortality and morbidity following colectomy. Albumin-Bilirubin can be applied to risk-stratify patients prior to colectomy.

Measuring Respiration in Isolated Murine Brain Mitochondria: Implications for Mechanistic Stroke Studies.

Measuring mitochondrial respiration in brain tissue is very critical in understanding the physiology and pathology of the central nervous system. Particularly, measurement of respiration in isolated mitochondria provides the advantage over the whole cells or tissues as the changes in respiratory function are intrinsic to mitochondrial structures rather than the cellular signaling that regulates mitochondria. Moreover, a high-throughput technique for measuring mitochondrial respiration minimizes the experimental time and the sample-to-sample variation. Here, we provide a detailed protocol for measuring respiration in isolated brain non-synaptosomal mitochondria using Agilent Seahorse XFe24 Analyzer. We optimized the protocol for the amount of mitochondria and concentrations of ADP, oligomycin, and trifluoromethoxy carbonylcyanide phenylhydrazone (FCCP) for measuring respiratory parameters for complex I-mediated respiration. In addition, we measured complex II-mediated respiratory parameters. We observed that 10 µg of mitochondrial protein per well, ADP concentrations ranging between 2.5 and 10 mmol/L along with 5 µmol/L of oligomycin, and 5 µmol/L of FCCP are ideal for measuring the complex I-mediated respiration in isolated mouse brain mitochondria. Furthermore, we determined that 2.5 µg of mitochondrial protein per well is ideal for measuring complex II-mediated respiration. Notably, we provide a discussion of logical analysis of data and how the assay could be utilized to design mechanistic studies for experimental stroke. In conclusion, we provide detailed experimental design for measurement of various respiratory parameters in isolated brain mitochondria utilizing a novel high-throughput technique along with interpretation and analysis of data.

Measurement of respiratory function in isolated cardiac mitochondria using Seahorse XFe24 Analyzer: applications for aging research.

Mitochondria play a critical role in the cardiomyocyte physiology by generating majority of the ATP required for the contraction/relaxation through oxidative phosphorylation (OXPHOS). Aging is a major risk factor for cardiovascular diseases (CVD) and mitochondrial dysfunction has been proposed as potential cause of aging. Recent technological innovations in Seahorse XFe24 Analyzer enhanced the detection sensitivity of oxygen consumption rate and proton flux to advance our ability study mitochondrial function. Studies of the respiratory function tests in the isolated mitochondria have the advantages to detect specific defects in the mitochondrial protein function and evaluate the direct mitochondrial effects of therapeutic/pharmacological agents. Here, we provide the protocols for studying the respiratory function of isolated murine cardiac mitochondria by measuring oxygen consumption rate using Seahorse XFe24 Analyzer. In addition, we provide details about experimental design, measurement of various respiratory parameters along with interpretation and analysis of data.

Depolarization of mitochondria in neurons promotes activation of nitric oxide synthase and generation of nitric oxide.

The diverse signaling events following mitochondrial depolarization in neurons are not clear. We examined for the first time the effects of mitochondrial depolarization on mitochondrial function, intracellular calcium, neuronal nitric oxide synthase (nNOS) activation, and nitric oxide (NO) production in cultured neurons and perivascular nerves. Cultured rat primary cortical neurons were studied on 7-10 days in vitro, and endothelium-denuded cerebral arteries of adult Sprague-Dawley rats were studied ex vivo. Diazoxide and BMS-191095 (BMS), activators of mitochondrial KATP channels, depolarized mitochondria in cultured neurons and increased cytosolic calcium levels. However, the mitochondrial oxygen consumption rate was unaffected by mitochondrial depolarization. In addition, diazoxide and BMS not only increased the nNOS phosphorylation at positive regulatory serine 1417 but also decreased nNOS phosphorylation at negative regulatory serine 847. Furthermore, diazoxide and BMS increased NO production in cultured neurons measured with both fluorescence microscopy and electron spin resonance spectroscopy, which was sensitive to inhibition by the selective nNOS inhibitor 7-nitroindazole (7-NI). Diazoxide also protected cultured neurons against oxygen-glucose deprivation, which was blocked by NOS inhibition and rescued by NO donors. Finally, BMS induced vasodilation of endothelium denuded, freshly isolated cerebral arteries that was diminished by 7-NI and tetrodotoxin. Thus pharmacological depolarization of mitochondria promotes activation of nNOS leading to generation of NO in cultured neurons and endothelium-denuded arteries. Mitochondrial-induced NO production leads to increased cellular resistance to lethal stress by cultured neurons and to vasodilation of denuded cerebral arteries.