Firearm-Related Violence in the Pediatric Population.

Children, particularly adolescents, are dying from firearm-related injuries. Screening for firearms, early recognition of firearm-related concerns, appropriate referrals, and follow-up are crucial to the safety of our patients and their families. Clinicians are strongly encouraged to address firearm-related violence during clinical encounters. Risk reduction, advocacy, and policy implementation are key in mitigating the long-term negative sequelae of firearm violence in youth. The epidemiology of firearm-related death, mass shootings, school firearm violence, adolescent health, prevention, injury patterns, postinjury care, policy, and resources are all discussed in this article. [Pediatr Ann. 2024;53(1):e28-e33.].

Judgment Errors in Surgical Care.

BACKGROUND: Human error is impossible to eliminate, particularly in systems as complex as healthcare. The extent to which judgment errors in particular impact surgical patient care or lead to harm is unclear. STUDY DESIGN: The American College of Surgeons NSQIP (2018) procedures from a single institution with 30-day morbidity or mortality were examined. Medical records were reviewed and evaluated for judgment errors. Preoperative variables associated with judgment errors were examined using logistic regression. RESULTS: Of the surgical patients who experienced a morbidity or mortality, 18% (31 of 170) experienced an error in judgment during their hospitalization. Patients with hepatobiliary procedure (odds ratio [OR] 5.4 [95% CI 1.23 to 32.75], p = 0.002), insulin-dependent diabetes (OR 4.8 [95% CI 1.2 to 18.8], p = 0.025), severe COPD (OR 6.0 [95% CI 1.6 to 22.1], p = 0.007), or with infected wounds (OR 8.2 [95% CI 2.6 to 25.8], p < 0.001) were at increased risk for judgment errors. CONCLUSIONS: Specific procedure types and patients with certain preoperative variables had higher risk for judgment errors during their hospitalization. Errors in judgment adversely impacted the outcomes of surgical patients who experienced morbidity or mortality in this cohort. Preventing or mitigating errors and closely monitoring patients after an error in judgment is prudent and may improve surgical safety.

Impact of Medicaid Expansion on Abdominal Surgery Morbidity, Mortality, and Hospital Readmission.

INTRODUCTION: Medicaid expansion's (ME) impact on postoperative outcomes after abdominal surgery remains poorly defined. We aimed to evaluate ME's effect on surgical morbidity, mortality, and readmissions in a state that expanded Medicaid (Virginia) compared to a state that did not (Tennessee) over the same time period. METHODS: Virginia Surgical Quality Collaborative (VSQC) American College of Surgeons National Surgical Quality Improvement Program data for Medicaid, uninsured, and private insurance patients undergoing abdominal procedures before Virginia's ME (3/22/18-12/31/18) were compared with post-ME (1/1/19-12/31/19), as were corresponding non-ME state Tennessee Surgical Quality Collaborative (TSQC) data for the same 2018 and 2019 time periods. Postexpansion odds ratios for 30-d morbidity, 30-d mortality, and 30-d unplanned readmission were estimated using propensity score-adjusted logistic regression models. RESULTS: In Virginia, 4753 abdominal procedures, 2097 pre-ME were compared to 2656 post-ME. In Tennessee, 5956 procedures, 2484 in 2018 were compared to 3472 in 2019. VSQC's proportion of Medicaid population increased following ME (8.9% versus 18.8%, P < 0.001) while uninsured patients decreased (20.4% versus 6.4%, P < 0.001). Post-ME VSQC had fewer 30-d readmissions (12.2% versus 6.0%, P = 0.013). Post-ME VSQC Medicaid patients had significantly lower probability of morbidity (-8.18, 95% confidence interval: -15.52 ∼ -0.84, P = 0.029) and readmission (-6.92, 95% confidence interval: -12.56 ∼ -1.27, P = 0.016) compared to pre-ME. There were no differences in probability of morbidity or readmission in the TSQC Medicaid population between study periods (both P > 0.05); there were no differences in mortality between study periods in VSQC and TSQC patient populations (both P > 0.05). CONCLUSIONS: ME was associated with decreased 30-d morbidity and unplanned readmissions in the VSQC. Data-driven policies accounting for ME benefits should be considered.

Long term employment following heart transplantation in the United States.

BACKGROUND: Employment is an important metric of post-transplant functional status and the quality of life yet remains poorly described after heart transplant. We sought to characterize the prevalence of employment following heart transplantation and identify patients at risk for post-transplant unemployment. METHODS: Adults undergoing single-organ heart transplantation (2007-2016) were evaluated using the UNOS database. Univariable analysis was performed after stratifying by employment status at 1-year post-transplant. Fine-Gray competing risk regression was used for risk adjustment. Cox regression evaluated employment status at 1 year with mortality. RESULTS: Of 10,132 heart transplant recipients who survived to 1 year and had follow-up, 22.0% were employed 1-year post-transplant. Employment rate of survivors increased to 32.9% by year 2. Employed individuals were more likely white (70.8% vs 60.4%, p < 0.01), male (79.6% vs 70.7% p < 0.01), held a job at listing/transplant (37.6% vs 7.6%, p < 0.01), and had private insurance (79.1% vs 49.5%, p < 0.01). Several characteristics were independently associated with employment including age, employment status at time of listing or transplant, race and ethnicity, gender, insurance status, education, and postoperative complications. Of 1,657 (14.0%) patients employed pretransplant, 58% were working at 1-year. Employment at 1year was independently associated with mortality with employed individuals having a 26% decreased risk of mortality. CONCLUSION: Over 20% of heart transplant patients were employed at 1 year and over 30% at 2 years, while 58% of those working pretransplant had returned to work by 1-year. While the major predictor of post-transplant employment is preoperative employment status, our study highlights the impact of social determinants of health.

Hydroxychloroquine Attenuates Myocardial Ischemic and Post-Ischemic Reperfusion Injury by Inhibiting the Toll-Like Receptor 9 - Type I Interferon Pathway.

Background: We hypothesized that hydroxychloroquine (HCQ) attenuates myocardial ischemia/reperfusion injury (IRI) via TLR9 - type I interferon (IFN-I) pathway inhibition. Methods: The left coronary artery of wild-type (WT) C57BL/6 and congenic TLR9-/- mice was occluded for 40 minutes, with or without 60 minutes of reperfusion (40'/0' or 40'/60'). Either ODN-2088 or HCQ (TLR9 inhibitors), or ODN-1826 (TLR9 agonist) was administered to determine effect on infarct size (IS). After 40'/0', cardiac perfusate (CP) was collected from harvested hearts and administered to either intact WT mice after 20 minutes of ischemia or isolated splenocytes. Type-I interferon (IFNα and IFNß) levels were measured in plasma and splenocyte culture supernatant, and levels of damage associated molecular patterns HMGB1 and cell-free DNA (cfDNA) were measured in CP. Results: After 40'/60', WT mice treated with HCQ or ODN-2088 had significantly reduced IS. TLR9-/- mice and HCQ-treated WT mice undergoing 40'/0' and 40'/60' similarly attenuated IS, with significantly lower IFN-Is in CP after 40'/0' and in plasma after 40'/60'. IS was significantly increased in 40'/0' CP-treated and ODN-1826-treated 20'/60' WT mice. CP-treated WT splenocytes produced significantly higher IFN-I in culture supernatant, which was significantly reduced with HCQ. Conclusions: The TLR9-IFN-I-mediated inflammatory response contributes significantly to both ischemic and post-ischemic myocardial ischemia-reperfusion injury. HMGB1 and cfDNA released from ischemic myocardium activated the intra-myocardial TLR9 - IFN-I inflammatory pathway during ischemia and the extra-myocardial TLR9 - IFN-I inflammatory pathway during reperfusion. Hydroxychloroquine reduces production of IFN-I and attenuates myocardial IRI, likely by inhibiting the TLR9-IFN-I pathway.

Errors in Surgery: A Case Control Study.

OBJECTIVE: While errors can harm patients they remain poorly studied. This study characterized errors in the care of surgical patients and examined the association of errors with morbidity and mortality. BACKGROUND: Errors have been reported to cause <10% or >60% of adverse events. Such discordant results underscore the need for further exploration of the relationship between error and adverse events. METHODS: Patients with operations performed at a single institution and abstracted into the American College of Surgeons National Surgical Quality Improvement Program from January 1, 2018, to December 31, 2018 were examined. This matched case control study comprised cases who experienced a postoperative morbidity or mortality. Controls included patients without morbidity or mortality, matched 2:1 using age (±10 years), sex, and Current Procedural Terminology (CPT) group. Two faculty surgeons independently reviewed records for each case and control patient to identify diagnostic, technical, judgment, medication, system, or omission errors. A conditional multivariable logistic regression model examined the association between error and morbidity. RESULTS: Of 1899 patients, 170 were defined as cases who experienced a morbidity or mortality. The majority of cases (n=93; 55%) had at least 1 error; of the 329 matched control patients, 112 had at least 1 error (34%). Technical errors occurred most often among both cases (40%) and controls (23%). Logistic regression demonstrated a strong independent relationship between error and morbidity (odds ratio=2.67, 95% confidence interval: 1.64-4.35, P <0.001). CONCLUSION: Errors in surgical care were associated with postoperative morbidity. Reducing errors requires measurement of errors.

Topical Neck Cooling Without Systemic Hypothermia Attenuates Myocardial Ischemic Injury and Post-ischemic Reperfusion Injury.

Background: Following acute myocardial infarction (MI), irreversible damage to the myocardium can only be reduced by shortening the duration between symptom onset and revascularization. While systemic hypothermia has shown promising results in slowing pre-revascularization myocardial damage, it is resource intensive and not conducive to prehospital initiation. We hypothesized that topical neck cooling (NC), an easily implemented therapy for en route transfer to definitive therapy, could similarly attenuate myocardial ischemia-reperfusion injury (IRI). Methods: Using an in vivo mouse model of myocardial IRI, moderate systemic hypothermia or NC was applied following left coronary artery (LCA) occlusion and subsequent reperfusion, at early, late, and post-reperfusion intervals. Vagotomy was performed after late NC in an additional group. Hearts were harvested to measure infarct size. Results: Both hypothermia treatments equally attenuated myocardial infarct size by 60% compared to control. The infarct-sparing effect of NC was temperature-dependent and timing-dependent. Vagotomy at the gastroesophageal junction abolished the infarct-sparing effect of late NC. Cardiac perfusate isolated following ischemia had significantly reduced cardiac troponin T, HMGB1, cell-free DNA, and interferon α and ß levels after NC. Conclusions: Topical neck cooling attenuates myocardial IRI in a vagus nerve-dependent manner, with an effect comparable to that of systemic hypothermia. NC attenuated infarct size when applied during ischemia, with earlier initiation resulting in superior infarct sparing. This novel therapy exerts a cardioprotective effect without requiring significant change in core temperature and may be a promising practical strategy to attenuate myocardial damage while patients await definitive revascularization.

Subcostal lymph nodes: An unusual sentinel lymph node basin in cutaneous melanoma.

BACKGROUND AND OBJECTIVES: Lymphatic drainage from subcostal nodes, along the costal groove, have not previously been characterized as sites for melanoma drainage and metastasis. This study reports a series of patients with subcostal nodes draining primary melanomas, with characterization of the sites of primary melanomas that drain to these nodes. METHODS: Patients who presented to our institution between 2005 and 2020 with documented cutaneous melanoma and sentinel lymph node biopsy of a subcostal node (sentinel = S), or metastases to subcostal nodes later in clinical management (recurrent = R) were included. Patient demographics, melanoma pathology, nodal features, imaging information, surgical approaches, and outcomes data were collected. RESULTS: Six patients had subcostal sentinel nodes (SNs). Primary sites included the posterior trunk and lateral chest wall. Subcostal nodes were found under ribs 10-12. Subcostal SNs had at least one dimension measuring 3 mm or less. There were no surgical complications related to removing the subcostal SN. CONCLUSIONS: Melanoma can metastasize to subcostal lymph nodes and be found at the time of SN biopsy or identified at recurrence. These small nodes are fed by lymphatic channels that run in the neurovascular bundle under the ribs. When lymphatic mapping identifies a subcostal SN, it should be excised.

A Novel Fascial Flap Technique After Inguinal Complete Lymph Node Dissection for Melanoma.

INTRODUCTION: Inguinal complete lymph node dissection (CLND) for metastatic melanoma exposes the femoral vein and artery. To protect femoral vessels while preserving the sartorius muscle, we developed a novel sartorius and adductor fascial flap (SAFF) technique for coverage. METHODS: The SAFF technique includes dissection of fascia off sartorius and/or adductor muscles, rotation over femoral vasculature, and suturing into place. Patients who underwent inguinal CLND with SAFF for melanoma at our institution were identified retrospectively from a prospectively-collected database. Patient characteristics and post-operative outcomes were obtained. Multivariate logistic regression assessed associations of palpable and non-palpable disease with wound complications. RESULTS: From 2008 to 2019, 51 patients underwent CLND with SAFF. Median age was 62 years, and 59% were female. Thirty-one (61%) patients were presented with palpable disease and 20 (39%) had non-palpable disease. Fifty-five percent (95% confidence interval CI: 40%-69%) experienced at least one wound complication: wound infection was most common (45%; 95% CI: 31%-60%), while bleeding was the least (2%; 95% CI: 0.05%-11%). Complications were similar, with and without palpable disease. CONCLUSIONS: The SAFF procedure covers femoral vessels, minimizes bleeding, preserves the sartorius muscle, and uses standard surgical techniques easily adoptable by surgeons who perform inguinal CLND.

Asymmetric walking on an incline affects aspects of positive mechanical work asymmetrically.

The purpose of this study was to determine the extent to which we could use a split-belt experimental paradigm to increase limb or joint work. Split-belt treadmill walking was combined with uphill walking at 0°, 5° and 10° in young, healthy individuals to assess whether we could specifically target increased force output between and within limbs. Thirteen healthy, young adults participated in this study. Participants performed walking trials with the left belt at 1.0 m/s and the right belt at 0.5 m/s. Repeated measures ANOVAs assessed the effects of speed of the treadmill belt and incline on total and joint specific positive extensor work as well as relative work. Mechanical work varied because of the speed and incline of the treadmill belt at the level of the total limb and across joints. Positive lower extremity relative joint work varied as a result of treadmill belt speed and treadmill incline. Positive mechanical work was greater on the limb that was on the faster treadmill belt, regardless of incline. Increases in relative knee but not hip joint work increased as incline increased. The current investigation shows that the nervous system can shift mechanical work production both between and within limbs to safely walk in a novel split-belt environment. This work extends previous research by demonstrating that researchers/clinicians can also use increasing treadmill incline (or some other means to add increased resistive forces) during split-belt treadmill walking to encourage increased mechanical output at particular limbs and/or joints which may have rehabilitation implications.

A dual-institutional study on first-year practice outcomes of pediatric surgeons who trained in the era of work hour restrictions.

BACKGROUND: In July 2003, an 80-h work week restriction for residencies was mandated. This was met with skepticism regarding its potential impact on operative training. We hypothesized no difference in outcomes for pediatric surgeons who trained under duty hour restrictions compared to historical complication rates. METHODS: Dual-institutional review of pediatric patients who underwent five of the most common operations (2013-2018) by first-year pediatric surgeons who trained under duty hour restrictions was performed. Tests of proportions were used to compare complication rates to published rates on data collected prior to 2003. RESULTS: Patient mean age was 10.1 years. No significant differences (p values > 0.05) were found in laparoscopic appendectomy rates of infection, bleeding or intra-abdominal abscess compared to previously published rates. Pyloromyotomy rates of infection or duodenal perforation were not different. No differences were detected in rates of infection, recurrence or testicular atrophy for inguinal hernia repair. Umbilical hernia rates of infection, bleeding, and recurrence were also not different. There was no difference in CVC rates of hemopneumothoraces; significantly more bleeding events were detected (1.2% vs. 0.1%; p value = 0.04). CONCLUSION: In this study, first-year complication rates of pediatric surgeons who trained under duty hour restrictions were not significantly different when compared to published rates.

Pediatric surgical errors: A systematic scoping review.

BACKGROUND: Medical errors were largely concealed prior to the landmark report "To Err Is Human". The purpose of this systematic scoping review was to determine the extent pediatric surgery defines and studies errors, and to explore themes among papers focused on errors in pediatric surgery. METHODS: The methodological framework used to conduct this scoping study has been outlined by Arksey and O'Malley. In January 2020, PubMed, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched. Oxford Level of Evidence was assigned to each study; only studies rated Level 3 or higher were included. RESULTS: Of 3,064 initial studies, 12 were included in the final analysis: 4 cohort studies, and 8 outcome/audit studies. This data represented 5,442,000 aggregate patients and 8,893 errors. There were 6 different error definitions and 5 study methods. Common themes amongst the studies included a systems-focused approach, an increase in errors seen with increased complexity, and studies exploring the relationship between error and adverse events. CONCLUSIONS: This study revealed multiple error definitions, multiple error study methods, and common themes described in the pediatric surgical literature. Opportunities exist to improve the safety of surgical care of children by reducing errors. Original Scientific Research Type of Study: Systematic Scoping Review Level of Evidence Rating: 1.

Defining and Studying Errors in Surgical Care: A Systematic Review.

OBJECTIVE: Our objective was to determine the extent surgical disciplines categorize, define, and study errors, then use this information to provide recommendations for both current practice and future study. SUMMARY OF BACKGROUND DATA: The report "To Err is Human" brought the ubiquity of medical errors to public attention. Variability in subsequent literature suggests the true prevalence of error remains unknown. METHODS: In January 2020, PubMed, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials were searched. Only studies with Oxford Level of Evidence Level 3 or higher were included. RESULTS: Of 3064 studies, 92 met inclusion criteria: 6 randomized controlled trials, 4 systematic reviews, 24 cohort, 10 before-after, 35 outcome/audit, 5 cross sectional and 8 case-control studies. Over 15,933,430 patients and 162,113 errors were represented. There were 6 broad error categories, 13 different definitions of error, and 14 study methods. CONCLUSIONS: Reported prevalence of error varied widely due to a lack of standardized categorization, definitions, and study methods. Future research should focus on immediately recognizing errors to minimize harm.

How Total Performance Scores of Medicare Value-Based Purchasing Program Hospitals Change Over Time.

BACKGROUND AND PURPOSE: The Medicare Value-Based Purchasing (VBP) program established performance-based financial incentives for hospitals. We hypothesized that total performance scores (TPS) would vary by hospital type. METHODS: Value-Based Purchasing reports were collected from 2015 to 2017 and merged with the Centers for Medicare and Medicaid Services (CMS) Impact File data. A total of 3,005 hospitals were grouped into physician-owned surgical hospitals (POSH), accountable care organizations (ACO), Kaiser, Vizient, and General hospitals. Longitudinal linear mixed-effects models compared temporal differences of TPS and secondary composite outcome, process, patient satisfaction, safety, and cost efficiency measures between hospital types. RESULTS: Total performance scores decreased across all hospital types (p < .001). Physician-owned surgical hospitals had the highest TPS (59.9), followed by Kaiser (49.2), ACO (36.7), General (34.8), and Vizient (30.7) (p < .001). Hospital types differed significantly in size, geography, mean case-mix index, Medicare patient discharges, percent Medicare days to inpatient days, Disproportionate Share Hospital payments, and uncompensated care per claim. Scores improved in 84% of POSH and 14.6% of Kaiser hospitals using score reallocations. CONCLUSION: In comparison with General hospitals, the TPS was higher for POSH and Kaiser and lower for Vizient in part due to weighting reallocation and individual domain scores. IMPLICATIONS: Centers for Medicare and Medicaid Services scoring system changes have not addressed the methodological biases favoring certain hospital types.

Topical Neck Cooling Prolongs Survival of Rats with Intra-Abdominal Feculent Sepsis by Activation of the Vagus Nerve.

Global hypothermia prolongs survival in rats with intraabdominal feculent sepsis by inhibiting inflammatory responses. We hypothesized that topical neck cooling (TNC) has similar benefits. Septic shock was induced by cecal ligation and incision (CLI) in Sprague Dawley rats. Rats were randomized to sham laparotomy, control with CLI, CLI with TNC, or vagotomy at the gastroesophageal junction before CLI and TNC. Two more groups underwent peritoneal washout with and without TNC two hours after CLI. TNC significantly lowered neck skin temperature (16.7 ± 1.4 vs. 30.5 ± 0.6 °C, p < 0.05) while maintaining core body normothermia. TNC rats recovered from anesthesia 70 min earlier than the control (p < 0.05). Three hours following CLI, the control and vagotomy with TNC groups had significantly more splenic contraction, fewer circulating leukocytes and higher plasma IL-1ß, IL-10 and TNF-α levels than TNC rats (p < 0.05). TNC prolonged survival duration after CLI by a median of four hours vs. control (p < 0.05), but no benefit was seen if vagotomy preceded TNC. Peritoneal washout alone increased survival by 3 h (9.2 (7.8-10.5) h). Survival duration increased dramatically with TNC preceding washout, to a 56% survival rate (>10 days). TNC significantly prolonged the survival of rats with severe intraabdominal sepsis by inhibiting systemic proinflammatory responses by activating vagal anti-inflammatory pathways.

Intracellular Hepatitis C Virus Modeling Predicts Infection Dynamics and Viral Protein Mechanisms.

Hepatitis C virus (HCV) infection is a global health problem, with nearly 2 million new infections occurring every year and up to 85% of these infections becoming chronic infections that pose serious long-term health risks. To effectively reduce the prevalence of HCV infection and associated diseases, it is important to understand the intracellular dynamics of the viral life cycle. Here, we present a detailed mathematical model that represents the full hepatitis C virus life cycle. It is the first full HCV model to be fit to acute intracellular infection data and the first to explore the functions of distinct viral proteins, probing multiple hypotheses of cis- and trans-acting mechanisms to provide insights for drug targeting. Model parameters were derived from the literature, experiments, and fitting to experimental intracellular viral RNA, extracellular viral titer, and HCV core and NS3 protein kinetic data from viral inoculation to steady state. Our model predicts higher rates for protein translation and polyprotein cleavage than previous replicon models and demonstrates that the processes of translation and synthesis of viral RNA have the most influence on the levels of the species we tracked in experiments. Overall, our experimental data and the resulting mathematical infection model reveal information about the regulation of core protein during infection, produce specific insights into the roles of the viral core, NS5A, and NS5B proteins, and demonstrate the sensitivities of viral proteins and RNA to distinct reactions within the life cycle.IMPORTANCE We have designed a model for the full life cycle of hepatitis C virus. Past efforts have largely focused on modeling hepatitis C virus replicon systems, in which transfected subgenomic HCV RNA maintains autonomous replication in the absence of virion production or spread. We started with the general structure of these previous replicon models and expanded it to create a model that incorporates the full virus life cycle as well as additional intracellular mechanistic detail. We compared several different hypotheses that have been proposed for different parts of the life cycle and applied the corresponding model variations to infection data to determine which hypotheses are most consistent with the empirical kinetic data. Because the infection data we have collected for this study are a more physiologically relevant representation of a viral life cycle than data obtained from a replicon system, our model can make more accurate predictions about clinical hepatitis C virus infections.

Chronic Myocardial Ischemia Leads to Loss of Maximal Oxygen Consumption and Complex I Dysfunction.

BACKGROUND: Cardiomyocytes rely heavily on mitochondrial energy production through oxidative phosphorylation. Chronic myocardial ischemia may cause mitochondrial dysfunction and affect ATP formation. Metabolic changes due to ischemia alters cardiac bioenergetics and hence myocardial function and overall bioenergetic state. Here, we evaluate differences in functional status of respiratory complexes in mitochondrial isolates extracted from left atrial appendage tissue (LAA) from patients undergoing cardiac surgery, with and without chronic ischemia. METHODS: Mitochondrial isolates were extracted from LAA in ischemic coronary artery bypass grafting patients (n = 8) and non-ischemic control patients (n = 6) undergoing other cardiac surgery (valve repair/replacement). Coupling and electron transport chain assays were performed using Seahorse XFe 96 (Agilent Technologies, Santa Clara, CA) analyzer. Oxygen consumption rates were measured to calculate respiration states. RESULTS: Respiratory control rate (RCR) in ischemic patients was significantly lower than control patients (6.17 ± 0.27 vs 7.11 ± 0.31, respectively; p < 0.05). This is the result of minimal, non-significant state 3ADP and state 4O changes in chronic ischemia. Complex I respiration is diminished in ischemic tissue (99.1 ± 14.9 vs 257.8 ± 65.2 in control; p < 0.01). Maximal complex I/II respiration ratio was significantly lower in ischemic patients (58.9% ± 5.5% vs 90.9% ± 8.8%; p < 0.05), a difference that was also seen in complex I/IV ratios (p < 0.05). There was no significant difference in complex II/IV ratios between groups. CONCLUSIONS: Ischemic patients have aberrant mitochondrial function, highlighted by a lowered RCR. All ratios involving complex I were affected, suggesting that the insufficient ATP formation is predominantly due to complex I dysfunction. Complex II and IV respiration may be impaired as well, but to a lesser extent.

Metabolic Impact of Rapamycin (Sirolimus) and B-Estradiol Using Mouse Embryonic Fibroblasts as a Model for Lymphangioleiomyomatosis.

INTRODUCTION: Lymphangioleiomyomatosis (LAM) is a rare, progressive cystic lung disease that predominantly affects women of childbearing age. Exogenous rapamycin (sirolimus) has been shown to improve clinical outcomes and was recently approved to treat LAM, whereas estrogen (E2) is implicated in disease progression. No consistent metabolic model currently exists for LAM, therefore wild-type mouse embryonic fibroblasts (MEF +/+) and TSC2 knockout cells (MEF -/-) were used in this study as a model for LAM. METHODS: Oxygen consumption rates (OCR) and redox potential were measured to determine metabolic state across control cells, MEF +/+ and -/- cells treated with rapamycin (Rapa), and MEF +/+ and -/- cells treated with E2. An XF96 extracellular flux analyzer from Seahorse Bioscience® was used to measure OCR, and a RedoxSYS™ ORP was used to measure redox potential. RESULTS: OCR of MEF -/- cells treated with rapamycin (MEF -/- Rapa) versus MEF -/- control were significantly lower across all conditions. The static oxidation reduction potential of the MEF -/- Rapa group was also lower, approaching significance. The coupling efficiency and ratio of ATP-linked respiration to maximum respiration were statistically lower in MEF -/- Rapa compared to MEF +/+ Rapa. There were no significant metabolic findings across any of the MEF cells treated with E2. MEF -/- control cells versus MEF +/+ control cells were not found to significantly differ. CONCLUSION: MEF cells are thought to be a feasible metabolic model for LAM, which has implications for future pharmacologic and biologic testing.

Novel vs clinical organ preservation solutions: improved cardiac mitochondrial protection.

BACKGROUND: Heart transplantation remains the gold standard for end-stage heart failure, with current ex vivo organ storage times limited to 4 to 6 h before critical tissue damage occurs. Many preservation solutions exist in an attempt to limit both ischemic and reperfusion damage. In order to compare the effects of various storage solutions, mitochondrial function can be used to provide a sensitive analysis of cellular metabolic function. METHODS: Experimental plates were seeded with cardiac myoblasts and kept in suspended animation for either 4 or 8 h at either 4o or 21 °C, in Celsior®, Perfadex®, or Somah storage solutions. Cells were then reanimated for 1 h at 37 °C to simulate a reperfusion or clinical transplant scenario. Cellular bioenergetics were measured immediately thereafter to examine biochemical differences between preservation solutions and their effectiveness on preserving metabolic function. RESULTS: The oxygen consumption rates of Somah solution were significantly higher than Celsior® and Perfadex® at 4 °C, with the exception of Perfadex® at 4o for 4 h. This effect was sustained up to 8 h. At 21 °C, oxygen consumption rates of Somah solution are significantly higher than Celsior® and Perfadex® at basal conditions after 4 h, but this effect is not sustained after 8 h. CONCLUSIONS: The purpose of this experiment was to study the efficacy of various preservation solutions on a mitochondrial level. The significantly higher oxygen consumption rates of Somah at 4 °C suggests that Somah solution may have the ability to protect cellular mitochondrial integrity, improve transplanted organ function by reducing ischemic-reperfusion injury, and thereby improve transplant outcomes. Given that Somah offers benefits over Celsior® and Perfadex® at 4 °C, it should be a target in future organ preservation solution research.