Development and Assessment of a Multi-Purpose Knowledge-Based Planning Model (RapidPlan) for Prostate Radiation

PURPOSE/OBJECTIVE(S)

RapidPlan (RP) is a knowledge-based planning (KBP) tool to improve plan quality, planning speed, and reduce inter-patient plan variability. For small to medium institutions, it is difficult to find sufficient patient numbers to configure a reliable KBP-RP model. This study aimed to build a multi-purpose KBP-RP model for prostate cancers.

MATERIALS/METHODS

A total of 124 prostate plans from 2018-2022 at our institution were selected to configure the initial RP model. After model training, outliers were removed. 77 patients were used for the final RP model. Three fine-tuned RP sub-models with different optimized constraints corresponding to prostate bed, prostate + seminal vesicles (SV), and prostate boost plans were generated. RP models were validated by comparing plan quality with the original manually optimized plans (MP). 54 independent plans were selected to validate the RP models. Validation included: dose to 99% and 2% of PTV (D99%, D2%), PTV conformity index (CI); for organs at risk (OARs), volume receiving >70Gy and >60Gy (V70Gy, V60Gy) to bladder and rectum, maximum dose (Dmax) to femur heads (FHs) and small bowel. Statistical t-test analysis was performed with a significance of p<0.05.

RESULTS

A total of 48/54 model-based plans were clinically approved after single RP optimization. 6/54 failed plans were prostate bed plans and were deemed acceptable after additional minor constraint adjustments. For PTV, D99%, D2%, and CI were comparable (p>0.05) to MP. Bladder and rectum V70Gy were comparable (p>0.05), and V60Gy were significantly lower to MP (p<0.05), with an average Dmean of 23.21±14.58Gy and 16.41±10.63Gy vs 26.36±16.89Gy and 18.24±12.81Gy for RP and MP. RP significantly reduced Dmax to FHs and small bowel (p<0.05), with average Dmax of 34.95±6.06Gy and 35.62±18.99Gy vs 36.81±7.05Gy and 38.14±17.81Gy, respectively.

CONCLUSION

Multi-purpose prostate RP model was configured and approved plans were generated after single optimization. Prostate RP plans had equivalent PTV coverage with better or comparable OAR constraints.

Unraveling the mechanisms of cardiolipin function: The role of oxidative polymerization of unsaturated acyl chains

Cardiolipin is a unique phospholipid of the inner mitochondrial membrane (IMM) as well as in bacteria. It performs several vital functions such as resisting osmotic rupture and stabilizing the supramolecular structure of large membrane proteins, like ATP synthases and respirasomes. The process of cardiolipin biosynthesis results in the production of immature cardiolipin. A subsequent step is required for its maturation when its acyl groups are replaced with unsaturated acyl chains, primarily linoleic acid. Linoleic acid is the major fatty acid of cardiolipin across all organs and tissues, except for the brain. Linoleic acid is not synthesized by mammalian cells. It has the unique ability to undergo oxidative polymerization at a moderately accelerated rate compared to other unsaturated fatty acids. This property can enable cardiolipin to form covalently bonded net-like structures essential for maintaining the complex geometry of the IMM and gluing the quaternary structure of large IMM protein complexes. Unlike triglycerides, phospholipids possess only two covalently linked acyl chains, which constrain their capacity to develop robust and complicated structures through oxidative polymerization of unsaturated acyl chains. Cardiolipin, on the other hand, has four fatty acids at its disposal to form covalently bonded polymer structures. Despite its significance, the oxidative polymerization of cardiolipin has been overlooked due to the negative perception surrounding biological oxidation and methodological difficulties. Here, we discuss an intriguing hypothesis that oxidative polymerization of cardiolipin is essential for the structure and function of cardiolipin in the IMM in physiological conditions. In addition, we highlight current challenges associated with the identification and characterization of oxidative polymerization of cardiolipin in vivo. Altogether, the study provides a better understanding of the structural and functional role of cardiolipin in mitochondria.

The Effects of Amyloid-β on Metabolomic Profiles of Cardiomyocytes and Coronary Endothelial Cells

BACKGROUND

An increasing number of experimental and clinical studies show a link between Alzheimer's disease and heart diseases such as heart failure, ischemic heart disease, and atrial fibrillation. However, the mechanisms underlying the potential role of amyloid-β (Aβ) in the pathogenesis of cardiac dysfunction in Alzheimer's disease remain unknown. We have recently shown the effects of Aβ 1 - 40 and Aβ 1 - 42 on cell viability and mitochondrial function in cardiomyocytes and coronary artery endothelial cells.

OBJECTIVE

In this study, we investigated the effects of Aβ 1 - 40 and Aβ 1 - 42 on the metabolism of cardiomyocytes and coronary artery endothelial cells.

METHODS

Gas chromatography-mass spectrometry was used to analyze metabolomic profiles of cardiomyocytes and coronary artery endothelial cells treated with Aβ 1 - 40 and Aβ 1 - 42. In addition, we determined mitochondrial respiration and lipid peroxidation in these cells.

RESULTS

We found that the metabolism of different amino acids was affected by Aβ 1 - 42 in each cell type, whereas the fatty acid metabolism is consistently disrupted in both types of cells. Lipid peroxidation was significantly increased, whereas mitochondrial respiration was reduced in both cell types in response to Aβ 1 - 42.

CONCLUSION

This study revealed the disruptive effects of Aβ on lipid metabolism and mitochondria function in cardiac cells.

Effects of Ferroptosis on the Metabolome in Cardiac Cells: The Role of Glutaminolysis

Ferroptosis is a novel iron-dependent regulated cell death mechanism that affects cell metabolism; however, a detailed metabolomic analysis of ferroptotic cells is not yet available. Here, we elucidated the metabolome of H9c2 cardioblasts by gas chromatography-mass spectrometry during ferroptosis induced by RSL3, a GPX4 inhibitor, in the presence of ferrostatin-1 (a ferroptosis inhibitor), XJB-5-131 (a mitochondrial-targeted ROS scavenger), or TSM-1005-44 (a newly developed cellular ROS scavenger). Results demonstrated that RSL3 decreased the levels of amino acids involved in glutathione synthesis more than two-fold. In contrast, saturated fatty acids levels were markedly increased in RSL3-challenged cells, with no effects on unsaturated fatty acids. RSL3 significantly altered the levels of mitochondrial tricarboxylic acid cycle intermediates; isocitrate and 2-oxoglutarate were found to increase, whereas succinate was significantly decreased in RSL3-challenged cells. Ferrostatin-1, XJB-5-131, and TSM-1005-44 prevented RSL3-induced cell death and conserved the metabolomic profile of the cells. Since 2-oxoglutarate is involved in the regulation of ferroptosis, particularly through glutamine metabolism, we further assessed the role of glutaminolysis in ferroptosis in H9c2 cardioblasts. Genetic silencing of GLS1, which encodes the K-type mitochondrial glutaminase (glutaminase C), protected against ferroptosis in the early stage. In conclusion, our study demonstrates that RSL3-induced ferroptosis impairs the metabolome of H9c2 cardioblasts.

Beta-Amyloid Instigates Dysfunction of Mitochondria in Cardiac Cells

Alzheimer’s disease (AD) includes the formation of extracellular deposits comprising aggregated β-amyloid (Aβ) fibers associated with oxidative stress, inflammation, mitochondrial abnormalities, and neuronal loss. There is an associative link between AD and cardiac diseases; however, the mechanisms underlying the potential role of AD, particularly Aβ in cardiac cells, remain unknown. Here, we investigated the role of mitochondria in mediating the effects of Aβ_1-40 and Aβ_1-42 in cultured cardiomyocytes and primary coronary endothelial cells. Our results demonstrated that Aβ_1-40 and Aβ_1-42 are differently accumulated in cardiomyocytes and coronary endothelial cells. Aβ_1-42 had more adverse effects than Aβ_1-40 on cell viability and mitochondrial function in both types of cells. Mitochondrial and cellular ROS were significantly increased, whereas mitochondrial membrane potential and calcium retention capacity decreased in both types of cells in response to Aβ_1-42. Mitochondrial dysfunction induced by Aβ was associated with apoptosis of the cells. The effects of Aβ_1-42 on mitochondria and cell death were more evident in coronary endothelial cells. In addition, Aβ_1-40 and Aβ_1-42 significantly increased Ca²⁺ -induced swelling in mitochondria isolated from the intact rat hearts. In conclusion, this study demonstrates the toxic effects of Aβ on cell survival and mitochondria function in cardiac cells.

Analysis of Mitochondrial Calcium Retention Capacity in Cultured Cells: Permeabilized Cells Versus Isolated Mitochondria

In response to various pathological stimuli, such as oxidative and energy stress accompanied by high Ca²⁺, mitochondria undergo permeability transition (PT) leading to the opening of the non-selective PT pores (PTP) in the inner mitochondrial membrane. Opening of the pores at high conductance allows the passage of ions and solutes <1.5 kD across the membrane, that increases colloid osmotic pressure in the matrix leading to excessive mitochondrial swelling. Calcium retention capacity (CRC) reflects maximum Ca²⁺ overload of mitochondria that occurs just before PTP opening. Quantification of CRC is important for elucidating the effects of different pathological stimuli and the efficacy of pharmacological agents on the mitochondria. Here, we performed a comparative analysis of CRC in mitochondria isolated from H9c2 cardioblasts, and in permeabilized H9c2 cells in situ to highlight the strengths and weaknesses of the CRC technique in isolated cell mitochondria vs. permeabilized cells. The cells were permeabilized by digitonin or saponin, and the Ca²⁺-sensitive fluorescence probe Calcium Green-5N was used in both preparations. Results demonstrated the interference of dye-associated fluorescence signals with saponin and the adverse effects of digitonin on mitochondria at high concentrations. Analysis of the CRC in permeabilized cells revealed a higher CRC in the saponin-permeabilized cells in comparison with the digitonin-permeabilized cells. In addition, the mitochondrial CRC in saponin-permeabilized cells was higher than in isolated mitochondria. Altogether, these data demonstrate that the quantification of the mitochondrial CRC in cultured cells permeabilized by saponin has more advantages compared to the isolated mitochondria.

Measurement of axial phase difference of density fluctuations owing to spontaneously excited waves by using microwave reflectometer on GAMMA 10/PDX

In the GAMMA 10/PDX tandem mirror, plasma with strong ion-temperature anisotropy is produced by using the ion cyclotron range of frequency waves. This anisotropy of ion temperature causes several Alfvén-Ion-Cyclotron (AIC) waves to spontaneously excite in the frequency range just below the ion cyclotron frequency. In addition, difference-frequency (DF) waves are excited in the radial inner region of the plasma by wave-wave coupling among the AIC waves. The radial density profiles were measured at multi-axial positions using a frequency-modulation reflectometer with an axial array of microwave antennas, and an axial variation of the density was found to be significant. In addition, a relative phase difference of the DF wave between axially separated two points was first obtained by finely choosing the probing frequency of the reflectometers with a maximum coherence used as a measure, indicating that the DF wave is a propagating wave, while the pump AIC waves are standing waves in the axial region of measurement.

Incidence of subsequent osteoporotic fractures after distal radius fractures and mortality of the subsequent distal radius fractures: a retrospective analysis of claims data of the Korea National Health Insurance Service

A better understanding of the features of subsequent fractures after distal radius fracture (DRF) is important for the prevention of further osteoporotic fractures. This study found that the cumulative incidence of subsequent osteoporotic fractures in South Korea increased over time and that the mortality rates of subsequent DRFs were lower than those of first-time DRFs.

INTRODUCTION

We examined the incidence of osteoporotic fractures following distal radius fractures (DRFs) and the mortality rate after subsequent DRFs using claims data from the Korea National Health Insurance (KNHI) Service.

METHODS

We identified records for 41,417 patients with first-time DRFs in 2012. The occurrence of osteoporotic fractures of the spine, hip, wrist, and humerus at least 6 months after the index DRF was tracked through 2016. All fractures were identified by specific diagnosis and procedure codes. One-year mortality rates and standardized mortality ratios (SMRs) for initial and subsequent DRFs were calculated for all patients.

RESULTS

The 4-year cumulative incidence of all subsequent osteoporotic fractures was 14.74% (6105/41,417; 9.47% in men, 15.9% in women). The number of associated subsequent fractures was 2850 for the spine (46.68%), 2271 for the wrist (37.2%), 708 for the hip (11.6%), and 276 for the humerus (4.52%). The cumulative mortality rate 1 year after the first-time and subsequent DRF was 1.47% and 0.71%, respectively, and the overall SMR was 1.48 (95% CI: 1.37-1.61) and 0.71 (95% CI: 0.42-1.21), respectively.

CONCLUSION

The cumulative incidence of osteoporotic fractures following DRFs increased over the study period and was higher among women. The cumulative mortality rates and SMRs of subsequent DRFs were lower than those of first-time DRFs at the 1-year follow-up. Given the increasing incidence rate of DRFs, the incidence of subsequent osteoporotic fractures may also increase.

Cardiometabolic risk prediction algorithms for young people with psychosis: a systematic review and exploratory analysis

OBJECTIVE

Cardiometabolic risk prediction algorithms are common in clinical practice. Young people with psychosis are at high risk for developing cardiometabolic disorders. We aimed to examine whether existing cardiometabolic risk prediction algorithms are suitable for young people with psychosis.

METHODS

We conducted a systematic review and narrative synthesis of studies reporting the development and validation of cardiometabolic risk prediction algorithms for general or psychiatric populations. Furthermore, we used data from 505 participants with or at risk of psychosis at age 18 years in the ALSPAC birth cohort, to explore the performance of three algorithms (QDiabetes, QRISK3 and PRIMROSE) highlighted as potentially suitable. We repeated analyses after artificially increasing participant age to the mean age of the original algorithm studies to examine the impact of age on predictive performance.

RESULTS

We screened 7820 results, including 110 studies. All algorithms were developed in relatively older participants, and most were at high risk of bias. Three studies (QDiabetes, QRISK3 and PRIMROSE) featured psychiatric predictors. Age was more strongly weighted than other risk factors in each algorithm. In our exploratory analysis, calibration plots for all three algorithms implied a consistent systematic underprediction of cardiometabolic risk in the younger sample. After increasing participant age, calibration plots were markedly improved.

CONCLUSION

Existing cardiometabolic risk prediction algorithms cannot be recommended for young people with or at risk of psychosis. Existing algorithms may underpredict risk in young people, even in the face of other high-risk features. Recalibration of existing algorithms or a new tailored algorithm for the population is required.

CAPABILITIES OF THE ARADOS-WG03 REGIONAL NETWORK FOR LARGE-SCALE RADIOLOGICAL AND NUCLEAR EMERGENCY SITUATIONS IN ASIA

In 2015, the Asian Radiation Dosimetry Group established a regional network of biological dosimetry laboratories known as the ARADOS-WG03 (Working Group 03; Biological Dosimetry). A survey was conducted in 2017 to evaluate the capabilities and capacities of the participating laboratories for emergency preparedness and responses in large-scale nuclear and/or radiological incidents. The results of this survey were identified and assessed. The data provide important information on the current state of emergency cytogenetic biological dosimetry capabilities in the Asian region.

Social capital and students’ health: results of the splash study

Background

Universities around the world are challenged with rising rates of mental health problems among their students. Cumulative evidence demonstrated that aspects of the social environment, including social capital, play an important role in mental health. This study aimed to determine the prevalence of depressive symptoms among university students from across the globe and to investigate whether social capital was associated with depressive symptoms in university students.

Methods

A cross-sectional study was conducted in Albania, Brazil, Germany, Italy, Malaysia Oman, South Korea, Switzerland, Taiwan and the USA in 2018/2019. Data were obtained through self-administered questionnaire, including questions on sociodemographic characteristics and depressive symptoms. The BDI-S was used to assess the presence of depressive symptoms. Multilevel analyses were conducted to assess the relationship between social capital and depressive, adjusting for individual covariates (e.g. perceived stress and health behaviours) and country-level characteristics (e.g. democracy type).

Results

A total 3894 students participated. Out of all participants almost 47% presented clinically relevant depressive symptoms. The prevalence of depressive symptoms was highest among students identifying as other than male or female (48.7%), among students with low socioeconomic status (59.5%) and among students with low levels of cognitive (65.3%) and behavioural social capital (57.0%). Even after adjustment in multilevel logistic regression analyses, depressive symptoms remained significantly associated with low levels of cognitive social capital (OR = 1.49, 95% CI: 1.06 to 2.10) and low level of behavioural social capital (OR = 1.36, 95% CI: 1.08 to 1.71).

Conclusions

Social capital may play an important role in mental health problems in the university setting. The study identified significant opportunities for future research and health promotion strategies among students.

Key messages

Key factors associated with depressive symptoms among university students were low levels of behavioural and cognitive social capital. Health promotion programs targeting young persons with depressive symptoms should include effective components of social epidemiology such as social capital.

Impacts of climate change on snow accumulation and melting processes over mountainous regions in Northern California during the 21st century

A point-location-based analysis of future climate change impacts on snow accumulation and melting processes was conducted over three study watersheds in Northern California during a 90-year future period by means of snow regime projections. The snow regime projections were obtained by means of a physically-based snow model with dynamically downscaled future climate projections. Then, atmospheric and snow-related variables, and their interrelations during the 21st century were investigated to reveal future climate change impacts on snow accumulation and melting processes. The analysis shows large reductions in snow water equivalent (SWE), snowfall to precipitation (S/P) ratio, and snowmelt through the 21st century. Timing of the peak of the SWE and snowmelt will also change in the future. Meanwhile, the analysis in this study shows that air temperature rise will affect, but will not dominate the future change in snowmelt over the study watersheds. This result implies the importance of considering atmospheric variables other than air temperature, such as precipitation, shortwave radiation, relative humidity, and wind speed even if these variables will not clearly change during the 21st century.

Abstract 854: The Role of Mitochondrial Permeability Transition in the Regulation of ETC Supercomplexes Assembly by OPA1

Optic atrophy type 1 (OPA1), a dynamin-related GTPase is the inner mitochondrial membrane (IMM) protein, which, in addition to mitochondrial fusion, participates in maintaining the structural integrity of the IMM. The function and topography of the IMM is also regulated by changes in the matrix volume. Opening of the mitochondrial permeability transition pores (PTP) is the leading cause of mitochondrial matrix swelling. However, the cause-and-effect relationship between OPA1 proteolytic cleavage and PTP induction remains unknown. Here, we elucidated the role of PTP in OPA1-mediated regulation of electron transport chain (ETC) supercomplexes (SCs) assembly. First, intact mitochondria isolated from the rat heart were used to analyze the effect of PTP induction on the cleavage of long (L)-OPA1. Calcium-induced mitochondrial swelling increased L-OPA1 cleavage (66%, P<0.001) associated with accumulation of short (S)-OPA1. Inhibition of swelling by sanglifehrin A (a PTP inhibitor) prevented L-OPA cleavage whereas tert-butyl hydroperoxide (TBH) had no effect on L-OPA levels. Second, OPA1 knockdown (KD) by siRNA in HEK cells resulted in a 74% decrease (P<0.001) in OPA1 protein expression but did not change the proportion of L-OPA1 to total OPA. Mitochondria isolated from OPA1 KD cells showed reduced calcium-stimulated swelling with no changes in protein levels of cyclophilin D, a major PTP regulator. OPA1 KD cells demonstrated a 20% increase (P<0.05) in calcium-induced ROS generation. Analysis of individual ETC complexes revealed significant reduction of protein levels of the complexes I, III, and IV in OPA1 KD cells. Likewise, activities of complexes I and IV were reduced (48% and 37%, respectively, P<0.01 for both). OPA1 KD cells contained 38% (P<0.05) less ATP whereas the citrate synthase activity reflecting mitochondria mass was not affected. Blue native PAGE analysis demonstrated a 35% decrease (P<0.01) of high molecular weight proteins (>100 kDa) and a 24% decrease (P<0.05) of the respirasome, the main SC, levels in OPA1 KD mitochondria. We conclude that mitochondrial swelling by PTP opening stimulates OPA1 cleavage, and reduced OPA1 levels result in cristae malformation including reduced respirasome levels and the ETC complexes activity.

Abstract 541: Uncovering the Physiological Role of Mitochondrial Respiratory Supercomplexes in the Heart

The assembly of mitochondrial electron transport chain (ETC) supercomplexes (SCs), particularly the respirasome containing complexes I, III, and IV have been shown to participate in facilitating electron transport, reducing ROS production and maintaining the structural integrity of individual ETC complexes. However, the physiological role of SCs in high energy demanding tissues such as the heart remains unknown. Here, we elucidated whether disassembly of SCs affects the cardiac function. Hearts isolated from adult male Sprague Dawley rats were perfused using a Langendorff-mode perfusion with Krebs-Henseleit solution (KHS) for the first 20 min (equilibration period) followed by perfusion in the following groups: (i) 40-min perfusion with KHS (n=4), (ii, iii) 20-min perfusion with rotenone (an inducer of SC dissociation) or vehicle (ethanol, n=8 for both), and (iv, v) 20-min perfusion with rotenone or vehicle followed by a 20-min perfusion with KHS without rotenone or vehicle (n=6 for both). Cardiac function was monitored throughout the entire perfusion period. At the end of each protocol, the mitochondria were isolated for analysis of SCs, permeability transition, respiration rates, and ROS production. We found that cardiac function between rats perfused with KHS (i) and ethanol (i, iii) had no significant difference, though rotenone perfused rats (ii and iv) had a significant reduction (<40%) in cardiac function associated with reduced oxygen consumption rates in these groups. Furthermore, a significant increase in ROS production (ii) and permeability transition pore opening (iv) was observed when the hearts were perfused with rotenone with and without subsequent washout, respectively. Analysis of SCs by blue native PAGE displayed a significant reduction in SC levels in both ethanol (iii and v) and rotenone (ii and iv) perfused rats. Surprisingly, there were no differences in SC levels between the ethanol (iii and v) and rotenone (ii and iv) perfused groups. In addition, incubation of isolated intact mitochondria with ethanol and acetaldehyde did not demonstrate any direct effects of these compounds on ETC SC assembly. In conclusion, our data demonstrate a lack of an associative link between mitochondrial ETC SCs and cardiac function in rats.

Elucidating the contribution of ETC complexes I and II to the respirasome formation in cardiac mitochondria

Mitochondrial electron transport chain (ETC) plays a central role in ATP synthesis, and its dysfunction is associated with human diseases. Recent studies revealed that individual ETC complexes are assembled into supercomplexes. The main supercomplex, respirasome composed of complexes I, III, and IV has been suggested to improve electron channeling and control ROS production, maintain the structural integrity of ETC complexes and prevent protein aggregation in the inner mitochondrial membrane. However, many questions related to the structural organization of the respirasome, particularly, a possible role of complexes I and II in respirasome formation remain unclear. Here, we investigated whether genetic and pharmacological inhibition of complexes I and II affect respirasome assembly in cardioblast cells and isolated cardiac mitochondria. Pharmacological inhibition of the enzymatic activity of complexes I and II stimulated disruption of the respirasome. Likewise, knockdown of the complex I subunit NDUFA11 stimulated dissociation of respirasome and reduced the activity of complexes I, III, and IV. However, silencing of the membrane-anchored SDHC subunit of complex II had no effect on the respirasome assembly but reduced the activity of complexes II and IV. Downregulation of NDUFA11 or SDHC reduced ATP production and increased mitochondrial ROS production. Overall, these studies, for the first time, provide biochemical evidence that the complex I activity, and the NDUFA11 subunit are important for assembly and stability of the respirasome. The SDHC subunit of complex II is not involved in the respirasome however the complex may play a regulatory role in respirasome formation.

BIODOSIMETRY AND BIODOSIMETRY NETWORKS FOR MANAGING RADIATION EMERGENCY

Biological dosimetry enables individual dose reconstruction in the case of unclear or inconsistent radiation exposure situations, especially when a direct measurement of ionizing radiation is not or is no longer possible. To be prepared for large-scale radiological incidents, networking between well-trained laboratories has been identified as a useful approach for provision of the fast and trustworthy dose assessments needed in such circumstances. To this end, various biodosimetry laboratories worldwide have joined forces and set up regional and/or nationwide networks either on a formal or informal basis. Many of these laboratories are also a part of global networks such as those organized by World Health Organization, International Atomic Energy Agency or Global Health Security Initiative. In the present report, biodosimetry networks from different parts of the world are presented, and the partners, activities and cooperation actions are detailed. Moreover, guidance for situational application of tools used for individual dosimetry is given.

Abstract 412: The Role of ETC Complexes I and II in the Respirasome Assembly in Heart Mitochondria

Mitochondrial electron transport chain (ETC) plays an important role in ATP synthesis and its dysfunction is associated with human diseases. Recent cryo-electron microscopy studies revealed that individual ETC complexes are assembled into supercomplexes (SCs). Structural organization and physiological role as well as mechanisms of assembling and maintenance of the SCs are yet not completely understood. ETC complexes contribute unequally to structural organization of SCs, particularly the respirasome, the main SC which contains complexes I, III, and IV in various stoichiometries. However, many questions related to structural organization of the respirasome, particularly, a possible role of complexes I and II in respirasome formation remain unclear. Here, we focus on the role of complexes I and II in structural organization of SCs using both genetic and chemical inhibition of complex I and complex II in H9c2 cardiac myoblast cells and isolated cardiac mitochondria. Respiratory SCs were analyzed by blue native polyacrylamide gel electrophoresis. Pharmacological inhibition of complex I by rotenone and complex II by malonate stimulated dissociation of respirasome. Rotenone inhibited whereas malonate had no effect on calcium-induced mitochondrial swelling, a marker of permeability transition. On the other hand, the rate of mitochondrial ROS production was remarkably (>5 fold) stimulated by rotenone but not by malonate. Knockdown of the complex I subunit NDUFA11, which according to cryo-electron microscopy studies interacts with complex III in respirasome formation, stimulated dissociation of respirasome and reduced the activity of complexes I, III, and IV but not complex II. Downregulation of the SDHC subunit of complex II had no effect on the respirasome assembly but reduced the activity of complexes II and IV. In addition, knockdown of NDUFA11 or SDHC significantly reduced ATP levels in the cells. Overall, these studies for the first time provide biochemical evidence that NDUFA11 subunit of complex I is important for structural integrity of respirasome whereas complex II is less likely contribute to the integrity of respirasome.

Inpatient burden of esophageal cancer and analysis of factors affecting in-hospital mortality and length of stay

Esophageal cancer (EC) continues to be a major source of morbidity and mortality in the United States. However, there has been a relative dearth of research into hospital utilization in patients with EC. This study examines temporal trends in hospital admissions, length of stay (LOS), mortality, and costs associated with EC. In addition, we also analyzed factors associated with inpatient mortality and LOS. We interrogated National Inpatient Sample (NIS), a large registry of inpatient data, to retrieve information about various demographic and factors associated with hospital stay in patients who were admitted for EC between the years 1998 and 2013 in the United States. After examining trends over time, multivariate analysis was performed to identify factors associated with LOS and mortality. During 1998-2013, 538,776 hospital stays with principal diagnosis of EC were reviewed. Number of hospital stays and inpatient charges increased by 397 per year (±67.8; P < 0.0001) and $3,033 per patient per year (±135; <0.0001) respectively. Mortality and LOS decreased by 0.23% per year (±0.03; P < 0.0001) and 0.07 days per year (±0.006; P < 0.0001) respectively. Multiple factors associated with LOS and mortality were outlined. Despite overall increase in hospital utilization with respect to number of admissions and inpatient charges, inpatient mortality and LOS associated with EC declined. Factors associated with inpatient mortality and LOS may help drive clinical decision-making and influence healthcare or hospital policy.