Mitochondrial proteomics on human fibroblasts for identification of metabolic imbalance and cellular stress

<p>Abstract</p> <p>Background</p> <p>Mitochondrial proteins are central to various metabolic activities and are key regulators of apoptosis. Disturbance of mitochondrial proteins is therefore often associated with disease. Large scale protein data are required to capture the mitochondrial protein levels and mass spectrometry based proteomics is suitable for generating such data. To study the relative quantities of mitochondrial proteins in cells from cultivated human skin fibroblasts we applied a proteomic method based on nanoLC-MS/MS analysis of iTRAQ-labeled peptides.</p> <p>Results</p> <p>When fibroblast cultures were exposed to mild metabolic stress – by cultivation in galactose medium- the amount of mitochondria appeared to be maintained whereas the levels of individual proteins were altered. Proteins of respiratory chain complex I and IV were increased together with NAD⁺-dependent isocitrate dehydrogenase of the citric acid cycle illustrating cellular strategies to cope with altered energy metabolism. Furthermore, quantitative protein data, with a median standard error below 6%, were obtained for the following mitochondrial pathways: fatty acid oxidation, citric acid cycle, respiratory chain, antioxidant systems, amino acid metabolism, mitochondrial translation, protein quality control, mitochondrial morphology and apoptosis.</p> <p>Conclusion</p> <p>The robust analytical platform in combination with a well-defined compendium of mitochondrial proteins allowed quantification of single proteins as well as mapping of entire pathways. This enabled characterization of the interplay between metabolism and stress response in human cells exposed to mild stress.</p

Explaining Myanmar's Regime Transition: The Periphery is Central

In 2010, Myanmar (Burma) held its first elections after 22 years of direct military rule. Few compelling explanations for this regime transition have emerged. This article critiques popular accounts and potential explanations generated by theories of authoritarian ‘regime breakdown’ and ‘regime maintenance’. It returns instead to the classical literature on military intervention and withdrawal. Military regimes, when not terminated by internal factionalism or external unrest, typically liberalise once they feel they have sufficiently addressed the crises that prompted their seizure of power. This was the case in Myanmar. The military intervened for fear that political unrest and ethnic-minority separatist insurgencies would destroy Myanmar’s always-fragile territorial integrity and sovereignty. Far from suddenly liberalising in 2010, the regime sought to create a ‘disciplined democracy’ to safeguard its preferred social and political order twice before, but was thwarted by societal opposition. Its success in 2010 stemmed from a strategy of coercive state-building and economic incorporation via ‘ceasefire capitalism’, which weakened and co-opted much of the opposition. Having altered the balance of forces in its favour, the regime felt sufficiently confident to impose its preferred settlement. However, the transition neither reflected total ‘victory’ for the military nor secured a genuine or lasting peace

Increased 5-year risk of stroke, atrial fibrillation, acute coronary syndrome, and heart failure in out-of-hospital cardiac arrest survivors compared with population controls:A nationwide registry-based study

AimLong-term risks of stroke, atrial fibrillation, or flutter (AF), acute coronary syndrome (ACS), and heart failure (HF) among survivors of out-of-hospital cardiac arrest (OHCA) are unknown. We aimed to examine 5-year risks of these outcomes among 30-day survivors of OHCA.MethodsThirty-day survivors of OHCA without a prior (or within 30 days after cardiac arrest) history of stroke, AF, ACS, or HF and population controls without a prior history of these conditions were identified using Danish nationwide registries. Five-year risks of stroke, AF, ACS, and HF standardized to the distributions of age, sex, and comorbidities among OHCA survivors and controls were obtained using multivariable regression.ResultsOf 4,362 30-day OHCA-survivors, 1,051 were stroke-, AF-, ACS-, and HF-naïve and matched with controls using age, sex, and time of OHCA event. Absolute five-year risks for OHCA survivors vs. controls were for stroke: 6.3% [95% confidence interval (CI) 4.1-8.5] vs. 2.0% [1.6-2.5], AF: 7.9% [5.7-10.2] vs. 2.6% [2.1-3.1], ACS: 5.0% [3.2-6.8] vs. 1.5% [1.1-1.9], and HF: 12.7% [10.1-15.4] vs. 1.2% [0.9-1.6], respectively. Corresponding relative risks were 3.18 [95% CI 1.76-4.61] for stroke, 3.03 [1.93-4.14] for AF, 3.23 [1.69-4.77] for ACS, and 10.40 [6.57-14.13] for HF.ConclusionWhen compared with population controls, OHCA survivors had significantly increased five-year risks of incident stroke, AF, ACS, and HF

Ischemic Stroke Severity and Mortality in Patients With and Without Atrial Fibrillation

Background Our objective was to investigate stroke severity and subsequent rate of mortality among patients with and without atrial fibrillation (AF). Contemporary data on stroke severity and prognosis in patients with AF are lacking. Methods and Results First‐time ischemic stroke patients from the Danish Stroke Registry (January 2005–December 2016) were included in an observational study. Patients with AF were matched 1:1 by sex, age, calendar year, and CHA2DS2‐VASc score with patients without AF. Stroke severity was determined by the Scandinavian Stroke Scale (0–58 points). The rate of death was estimated by Kaplan‐Meier plots and multivariable Cox regression. Among 86 458 identified patients with stroke, 17 205 had AF. After matching, 14 662 patients with AF and 14 662 patients without AF were included (51.8% women; median age, 79.6 years [25th–75th percentile, 71.8–86.0]). More patients with AF had very severe stroke (0–14 points) than patients without AF (13.7% versus 7.9%, P<0.01). The absolute rates of 30‐day and 1‐year mortality were significantly higher for patients with AF (12.1% and 28.4%, respectively) versus patients without AF (8.7% and 21.8%, respectively). This held true in adjusted models for 30‐day mortality (hazard ratio [HR], 1.40 [95% CI, 1.30–1.51]). However, this association became nonsignificant when additionally adjusting for stroke severity (HR, 1.10 [95% CI, 1.00–1.23]). AF was associated with a higher rate of 1‐year mortality (HR, 1.39 [95% CI, 1.32–1.46]), although it was mediated by stroke severity (HR, 1.15 [95% CI, 1.09–1.23], model including stroke severity). Conclusions In a contemporary nationwide cohort of patients with ischemic stroke, patients with AF had more severe strokes and higher mortality than patients without AF. The difference in mortality was mainly driven by stroke severity