Oxidative stress responses in biofilms.

Oxidizing agents are low-molecular-weight molecules that oxidize other substances by accepting electrons from them. They include reactive oxygen species (ROS), such as superoxide anions (O2-), hydrogen peroxide (H2O2), and hydroxyl radicals (HO-), and reactive chlorine species (RCS) including sodium hypochlorite (NaOCl) and its active ingredient hypochlorous acid (HOCl), and chloramines. Bacteria encounter oxidizing agents in many different environments and from diverse sources. Among them, they can be produced endogenously by aerobic respiration or exogenously by the use of disinfectants and cleaning agents, as well as by the mammalian immune system. Furthermore, human activities like industrial effluent pollution, agricultural runoff, and environmental activities like volcanic eruptions and photosynthesis are also sources of oxidants. Despite their antimicrobial effects, bacteria have developed many mechanisms to resist the damage caused by these toxic molecules. Previous research has demonstrated that growing as a biofilm particularly enhances bacterial survival against oxidizing agents. This review aims to summarize the current knowledge on the resistance mechanisms employed by bacterial biofilms against ROS and RCS, focussing on the most important mechanisms, including the formation of biofilms in response to oxidative stressors, the biofilm matrix as a protective barrier, the importance of detoxifying enzymes, and increased protection within multi-species biofilm communities. Understanding the complexity of bacterial responses against oxidative stress will provide valuable insights for potential therapeutic interventions and biofilm control strategies in diverse bacterial species.

Low Utilization of Synchronous Telemedicine in Pediatric Critical Care Interfacility Transport: Barriers and Lessons.

OBJECTIVE: The use of telemedicine has increased and may enhance the care of children during medical transport. We aimed to evaluate the feasibility of synchronous telemedicine connectivity before interfacility transport of critically ill children by a pediatric transport team. METHODS: We performed a prospective, observational feasibility study of the introduction of synchronous telemedicine into an established pediatric transport team from 2019 to 2020. The outcomes examined included connectivity, physician workload, transport team satisfaction, and patient care outcomes. RESULTS: Among 118 eligible transports, telemedicine was considered in 23 transports (19%), including 11 transports in which an attempt to connect was sought and 12 in which telemedicine activation was offered but not attempted. The median connection time was 2.9 minutes (interquartile range, 1.7-4.4 minutes), and clinical care was altered in 1 case. Connection failed in 2 cases (18.2%). In 50% of cases, concurrent medical control physician workload prevented activation. There were no perceived benefits in 41.7% of cases. Team members indicated the desire for future telemedicine use in only 54.6% of cases. CONCLUSIONS: We found low utilization of synchronous telemedicine in interfacility pediatric transport. The identified barriers included reliable connectivity, physician workload, and low perceived benefit. Lessons learned and future research suggestions are presented to mitigate these barriers.

Prevalence of insomnia and insomnia symptoms following mild-traumatic brain injury: A systematic review and meta-analysis.

Sleep is commonly disrupted following mild traumatic brain injury (mTBI), however there is a lack of consensus in the existing literature regarding the prevalence of insomnia/insomnia symptoms after injury. The aim of this review was to conduct a systematic review and meta-analysis of insomnia and insomnia symptoms' prevalence following mTBI. Full-text articles published in English in peer-reviewed journals, including adults with a clinical or self-reported mild traumatic brain injury diagnosis, were eligible for inclusion. Studies that assessed insomnia/insomnia symptoms after injury were included. Of the 2091 records identified, 20 studies were included in the review. 19 of these were meta-analysed (n = 95,195), indicating high heterogeneity among studies. Subgroup analyses indicated pooled prevalence estimates of post-mTBI insomnia disorder of 27.0% (95% CI 6.49-54.68) and insomnia symptoms of 71.7% (95% CI 60.31-81.85). The prevalence of insomnia is significantly higher in individuals who have sustained mild traumatic brain injury compared to prevalence estimates reported in the general population but high heterogeneity and methodological differences among studies make it difficult to provide reliable prevalence estimates. Future research should continue to advance our understanding of the onset, progression and impact of post-mild traumatic brain injury insomnia to promote the recovery and wellbeing of affected individuals. PROSPERO registration CRD42020168563.

Adrenergic Receptors in Individual Ventricular Myocytes: The Beta-1 and Alpha-1B Are in All Cells, the Alpha-1A Is in a Subpopulation, and the Beta-2 and Beta-3 Are Mostly Absent.

RATIONALE: It is unknown whether every ventricular myocyte expresses all 5 of the cardiac adrenergic receptors (ARs), ß1, ß2, ß3, α1A, and α1B. The ß1 and ß2 are thought to be the dominant myocyte ARs. OBJECTIVE: Quantify the 5 cardiac ARs in individual ventricular myocytes. METHODS AND RESULTS: We studied ventricular myocytes from wild-type mice, mice with α1A and α1B knockin reporters, and ß1 and ß2 knockout mice. Using individual isolated cells, we measured knockin reporters, mRNAs, signaling (phosphorylation of extracellular signal-regulated kinase and phospholamban), and contraction. We found that the ß1 and α1B were present in all myocytes. The α1A was present in 60%, with high levels in 20%. The ß2 and ß3 were detected in only ≈5% of myocytes, mostly in different cells. In intact heart, 30% of total ß-ARs were ß2 and 20% were ß3, both mainly in nonmyocytes. CONCLUSION: The dominant ventricular myocyte ARs present in all cells are the ß1 and α1B. The ß2 and ß3 are mostly absent in myocytes but are abundant in nonmyocytes. The α1A is in just over half of cells, but only 20% have high levels. Four distinct myocyte AR phenotypes are defined: 30% of cells with ß1 and α1B only; 60% that also have the α1A; and 5% each that also have the ß2 or ß3. The results raise cautions in experimental design, such as receptor overexpression in myocytes that do not express the AR normally. The data suggest new paradigms in cardiac adrenergic signaling mechanisms.

An Alpha-1A Adrenergic Receptor Agonist Prevents Acute Doxorubicin Cardiomyopathy in Male Mice.

Alpha-1 adrenergic receptors mediate adaptive effects in the heart and cardiac myocytes, and a myocyte survival pathway involving the alpha-1A receptor subtype and ERK activation exists in vitro. However, data in vivo are limited. Here we tested A61603 (N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl]methanesulfonamide), a selective imidazoline agonist for the alpha-1A. A61603 was the most potent alpha-1-agonist in activating ERK in neonatal rat ventricular myocytes. A61603 activated ERK in adult mouse ventricular myocytes and protected the cells from death caused by the anthracycline doxorubicin. A low dose of A61603 (10 ng/kg/d) activated ERK in the mouse heart in vivo, but did not change blood pressure. In male mice, concurrent subcutaneous A61603 infusion at 10 ng/kg/d for 7 days after a single intraperitoneal dose of doxorubicin (25 mg/kg) increased survival, improved cardiac function, heart rate, and cardiac output by echocardiography, and reduced cardiac cell necrosis and apoptosis and myocardial fibrosis. All protective effects were lost in alpha-1A-knockout mice. In female mice, doxorubicin at doses higher than in males (35-40 mg/kg) caused less cardiac toxicity than in males. We conclude that the alpha-1A-selective agonist A61603, via the alpha-1A adrenergic receptor, prevents doxorubicin cardiomyopathy in male mice, supporting the theory that alpha-1A adrenergic receptor agonists have potential as novel heart failure therapies.

A Myocardial Slice Culture Model Reveals Alpha-1A-Adrenergic Receptor Signaling in the Human Heart.

BACKGROUND: Translation of preclinical findings could benefit from a simple, reproducible, high throughput human model to study myocardial signaling. Alpha-1A-adrenergic receptors (ARs) are expressed at very low levels in the human heart, and it is unknown if they function. OBJECTIVES: To develop a high throughput human myocardial slice culture model, and to test the hypothesis that alpha-1A- ARs are functional in the human heart. METHODS: Cores of LV free wall 8 mm diameter were taken from 52 hearts (18 failing and 34 nonfailing). Slices 250 µm thick were cut with a Krumdieck apparatus and cultured using a rotating incubation unit. RESULTS: About 60 slices were cut from each LV core, and a typical study could use 96 slices. Myocyte morphology was maintained, and diffusion into the slice center was rapid. Slice viability was stable for at least 3 days in culture by ATP and MTT assays. The beta-AR agonist isoproterenol stimulated phospholamban phosphorylation, and the alpha-1A-AR agonist A61603 stimulated ERK phosphorylation, with nanomolar EC50 values in slices from both failing and nonfailing hearts. Strips cut from the slices were used to quantify activation of contraction by isoproterenol, A61603, and phenylephrine. The slices supported transduction by adenovirus. CONCLUSIONS: We have developed a simple, high throughput LV myocardial slice culture model to study signaling in the human heart. This model can be useful for translational studies, and we show for the first time that the alpha-1A-AR is functional in signaling and contraction in the human heart.

The alpha-1A adrenergic receptor agonist A61603 reduces cardiac polyunsaturated fatty acid and endocannabinoid metabolites associated with inflammation in vivo.

INTRODUCTION: Alpha-1-adrenergic receptors (α1-ARs) are G-protein coupled receptors (GPCRs) with three highly homologous subtypes (α1A, α1B, and α1D). Of these three subtypes, only the α1A and α1B are expressed in the heart. Multiple pre-clinical models of heart injury demonstrate cardioprotective roles for the α1A. Non-selective α1-AR activation promotes glycolysis in the heart, but the functional α1-AR subtype and broader metabolic effects have not been studied. OBJECTIVES: Given the high metabolic demands of the heart and previous evidence indicating benefit from α1A activation, we chose to investigate the effects of α1A activation on the cardiac metabolome in vivo. METHODS: Mice were treated for one week with a low, subpressor dose of A61603, a highly selective and potent α1A agonist. Cardiac tissue and serum were analyzed using a non-targeted metabolomics approach. RESULTS: We identified previously unrecognized metabolic responses to α1A activation, most notably broad reduction in the abundance of polyunsaturated fatty acids (PUFAs) and endocannabinoids (ECs). CONCLUSION: Given the well characterized roles of PUFAs and ECs in inflammatory pathways, these findings suggest a possible role for cardiac α1A-ARs in the regulation of inflammation and may offer novel insight into the mechanisms underlying the cardioprotective benefit of selective pharmacologic α1A activation.

Single-Blind, Randomized, Controlled Clinical Trial of Exercise in Ambulatory Spinal Muscular Atrophy: Why are the Results Negative?

BACKGROUND: The benefits of exercise on long-term health and well-being are well established. The possible benefits of exercise in Spinal Muscular Atrophy (SMA) have not been explored in a controlled clinical trial format. OBJECTIVE: To assess the effects of exercise on measures of function, strength, and exercise capacity in ambulatory SMA patients. METHODS: Fourteen participants, ages 10-48 years, were randomized to control and exercise cohorts after a 1 month lead-in period. The exercise group received 6 months of intervention. Thereafter, both groups received the intervention for the remaining 12 months. Participants were monitored for a total of 19 months. Exercise included individualized home-based cycling and strengthening. The primary outcome measure was distance walked during the six-minute walk test (6MWT). Secondary outcomes included strength, function, exercise capacity, quality of life and fatigue. RESULTS: Twelve participants completed the first 7 months of the study, and 9 completed all 19 months. At baseline, the groups were similar on all clinical variables. There were no group changes at any time point in the 6MWT, fatigue, or function. Percent-predicted VO2 max improved 4.9% in all participants in 6 months (p = 0.036) (n = 10). CONCLUSION: Daily exercise is safe in ambulatory SMA and should be encouraged. We did not uncover any deleterious effects on strength, function, or fatigue. Our study documented a reduction in oxidative capacity and a blunted conditioning response to exercise possibly representing an important insight into underlying pathophysiological mechanisms. These findings also may be linked causally to mitochondrial depletion in SMA and warrant further study.

Observational study of spinal muscular atrophy type I and implications for clinical trials.

OBJECTIVES: Prospective cohort study to characterize the clinical features and course of spinal muscular atrophy type I (SMA-I). METHODS: Patients were enrolled at 3 study sites and followed for up to 36 months with serial clinical, motor function, laboratory, and electrophysiologic outcome assessments. Intervention was determined by published standard of care guidelines. Palliative care options were offered. RESULTS: Thirty-four of 54 eligible subjects with SMA-I (63%) enrolled and 50% of these completed at least 12 months of follow-up. The median age at reaching the combined endpoint of death or requiring at least 16 hours/day of ventilation support was 13.5 months (interquartile range 8.1-22.0 months). Requirement for nutritional support preceded that for ventilation support. The distribution of age at reaching the combined endpoint was similar for subjects with SMA-I who had symptom onset before 3 months and after 3 months of age (p=0.58). Having 2 SMN2 copies was associated with greater morbidity and mortality than having 3 copies. Baseline electrophysiologic measures indicated substantial motor neuron loss. By comparison, subjects with SMA-II who lost sitting ability (n=10) had higher motor function, motor unit number estimate and compound motor action potential, longer survival, and later age when feeding or ventilation support was required. The mean rate of decline in The Children's Hospital of Philadelphia Infant Test for Neuromuscular Disorders motor function scale was 1.27 points/year (95% confidence interval 0.21-2.33, p=0.02). CONCLUSIONS: Infants with SMA-I can be effectively enrolled and retained in a 12-month natural history study until a majority reach the combined endpoint. These outcome data can be used for clinical trial design.

A Randomized, Controlled Clinical Trial of Exercise in Patients with Spinal Muscular Atrophy: Methods and Baseline Characteristics.

BACKGROUND: Spinal Muscular Atrophy (SMA) is a recessively-inherited neuromuscular disease characterized by weakness and muscle atrophy. Although anecdotal benefits from exercise have been noted, and despite promising pre-clinical and pilot reports, the effect of exercise has not been addressed in a controlled trial in SMA. OBJECTIVE: To assess the effects of exercise on measures of function, strength, and exercise capacity in ambulatory SMA patients. METHODS/DESIGN: An evaluator-blinded, randomized, controlled trial of aerobic and strengthening exercise in 14 ambulatory SMA patients aged 8-50 years. Patients will be randomized to either the exercise or control arm after the 1 month lead in period. During the first 6-months, the exercise group will receive the intervention while the other group serves as a control. After those 6 months, both groups will receive the intervention. The last 6-months of the study are designed to mimic real-world conditions where all participants are encouraged to continue on their own. Participants will be monitored throughout this 19 month study and will have in-person visits every three months. The primary outcome measure is the change in the total distance walked over 6-months on the six minute walk test (6MWT). Secondary outcome measures include maximal oxygen uptake (VO2 max), functional and strength assessments, pulmonary function, fatigue, and quality of life. DISCUSSION: The result of this prospective, single blinded, randomized and controlled clinical trial of exercise on an established functional outcome measure will have impact on clinical practice by providing important guidance to clinical management of SMA patients.

Prospective cohort study of spinal muscular atrophy types 2 and 3.

OBJECTIVE: To characterize the natural history of spinal muscular atrophy type 2 and type 3 (SMA 2/3) beyond 1 year and to report data on clinical and biological outcomes for use in trial planning. METHODS: We conducted a prospective observational cohort study of 79 children and young adults with SMA 2/3 who participated in evaluations for up to 48 months. Clinically, we evaluated motor and pulmonary function, quality of life, and muscle strength. We also measured SMN2 copy number, hematologic and biochemical profiles, muscle mass by dual x-ray absorptiometry (DXA), and the compound motor action potential (CMAP) in a hand muscle. Data were analyzed for associations between clinical and biological/laboratory characteristics cross-sectionally, and for change over time in outcomes using all available data. RESULTS: In cross-sectional analyses, certain biological measures (specifically, CMAP, DXA fat-free mass index, and SMN2 copy number) and muscle strength measures were associated with motor function. Motor and pulmonary function declined over time, particularly at time points beyond 12 months of follow-up. CONCLUSION: The intermediate and mild phenotypes of SMA show slow functional declines when observation periods exceed 1 year. Whole body muscle mass, hand muscle compound motor action potentials, and muscle strength are associated with clinical measures of motor function. The data from this study will be useful for clinical trial planning and suggest that CMAP and DXA warrant further evaluation as potential biomarkers.

Age at disease onset predicts likelihood and rapidity of growth failure among infants and young children with spinal muscular atrophy types 1 and 2.

Growth failure is nearly universal in spinal muscular atrophy type 1 and common in type 2, although acuity is often underappreciated at initial diagnosis. We reviewed 44 consecutive spinal muscular atrophy patients (28 type 1, 16 type 2) under 3 years at initial presentation. Growth failure was conventionally defined: weight below the fifth percentile or dropping 2 major percentiles over 6 months. Growth failure differed among subjects stratified by age at disease onset using the Kaplan-Meier method (P = 0.011). Median time to growth failure among subjects with onset between 0 to 3 months of age was 5 months; Only 1 of 22 avoided failure by 22 months of age. Median time to failure with disease onset between 4 to 6 months was 15 months. Most late onset (> 6 months) subjects avoided growth failure. Early clinical symptoms predict feeding dysfunction and growth failure. Immediate, proactive nutritional intervention is indicated for patients with early symptom onset.

Spinal muscular atrophy type III: trying to understand subtle functional change over time--a case report.

Spinal muscular atrophy is a relatively stable chronic disease. Patients may gradually experience declines in muscle strength and motor function over time. However, functional progression is difficult to document, and the mechanism remains poorly understood. An 11-year-old girl was diagnosed at 19 months and took a few steps without assistance at 25 months. She was evaluated for 54 months in a prospective multicenter natural history study. Outcome measures were performed serially. From 6 to 7.5 years, motor function improved. From 7.5 to 11 years, motor function declined with increasing growth. Manual muscle testing scores minimally decreased. Motor unit number estimation studies gradually increased over 4.5 years. Compared to the published natural history of spinal muscular atrophy type III, our patient lost motor function over time. However, she walked with assistance 2 years longer than expected. Our report highlights possible precipitating factors that could affect the natural history of spinal muscular atrophy type III.

ß-myosin heavy chain is induced by pressure overload in a minor subpopulation of smaller mouse cardiac myocytes.

RATIONALE: Induction of the fetal hypertrophic marker gene ß-myosin heavy chain (ß-MyHC) is a signature feature of pressure overload hypertrophy in rodents. ß-MyHC is assumed present in all or most enlarged myocytes. OBJECTIVE: To quantify the number and size of myocytes expressing endogenous ß-MyHC by a flow cytometry approach. METHODS AND RESULTS: Myocytes were isolated from the left ventricle of male C57BL/6J mice after transverse aortic constriction (TAC), and the fraction of cells expressing endogenous ß-MyHC was quantified by flow cytometry on 10,000 to 20,000 myocytes with use of a validated ß-MyHC antibody. Side scatter by flow cytometry in the same cells was validated as an index of myocyte size. ß-MyHC-positive myocytes constituted 3 ± 1% of myocytes in control hearts (n=12), increasing to 25 ± 10% at 3 days to 6 weeks after TAC (n=24, P<0.01). ß-MyHC-positive myocytes did not enlarge with TAC and were smaller at all times than myocytes without ß-MyHC (≈70% as large, P<0.001). ß-MyHC-positive myocytes arose by addition of ß-MyHC to α-MyHC and had more total MyHC after TAC than did the hypertrophied myocytes that had α-MyHC only. Myocytes positive for ß-MyHC were found in discrete regions of the left ventricle in 3 patterns: perivascular, in areas with fibrosis, and in apparently normal myocardium. CONCLUSIONS: ß-MyHC protein is induced by pressure overload in a minor subpopulation of smaller cardiac myocytes. The hypertrophied myocytes after TAC have α-MyHC only. These data challenge the current paradigm of the fetal hypertrophic gene program and identify a new subpopulation of smaller working ventricular myocytes with more myosin.

Thigh muscle volume measured by magnetic resonance imaging is stable over a 6-month interval in spinal muscular atrophy.

Changes in thigh muscle volume over 6 months were assessed using magnetic resonance imaging in 11 subjects aged 6 to 47 years with spinal muscular atrophy (4 type 2 and 7 type 3; 4 ambulatory and 3 nonambulatory). Muscle volume with normal and abnormal signal was measured using blinded, semiautomated analysis of reconstructed data. Volumes at baseline and 6 months were correlated with clinical function at each epoch. There was minimal increase in normal (0.3 ± 1.4 mL/cm) and total (0.1 ± 1.3 mL/cm) muscle. Muscle volume correlated closely with clinical function. Minimal interval change in muscle volume is consistent with the established clinical history of minimal disease progression over intervals shorter than 1 year. Relative constancy of muscle volume estimation and correlation with established functional measures suggest a role for segmental magnetic resonance imaging as a biomarker of treatment effect in future therapeutic trials.

Fatigue leads to gait changes in spinal muscular atrophy.

INTRODUCTION: Impaired mobility and fatigue are common in ambulatory spinal muscular atrophy (SMA) patients. The 6-minute walk test (6MWT) is a reliable measure of fatigue in SMA patients. To further evaluate fatigue, we used quantitative gait analysis during the 6MWT. METHODS: Nine subjects with SMA and 9 age- and gender-matched, healthy controls were evaluated. Gait parameters of speed and dynamic balance were correlated with 6MWT distance. Performance during the first and last 25 meters of the 6MWT was compared. RESULTS: Speed-related gait parameters and support base correlated with 6MWT distance. Walking performance was worse for SMA patients. The deterioration in stride length during the 6MWT was greater in SMA patients than in controls. CONCLUSIONS: Gait analysis detects fatigue, and the decrement in stride length may reflect selective muscle involvement in SMA. Further understanding of the mechanisms underlying fatigue may suggest additional targets for future therapeutic interventions.

Observational study of spinal muscular atrophy type 2 and 3: functional outcomes over 1 year.

OBJECTIVE: To characterize the short-term course of spinal muscular atrophy (SMA) in a genetically and clinically well-defined cohort of patients with SMA. DESIGN: A comprehensive multicenter, longitudinal, observational study. SETTING: The Pediatric Neuromuscular Clinical Research Network for SMA, a consortium of clinical investigators at 3 clinical sites. PARTICIPANTS: Sixty-five participants with SMA types 2 and 3, aged 20 months to 45 years, were prospectively evaluated. INTERVENTION: We collected demographic and medical history information and determined the SMN 2 copy number. MAIN OUTCOME MEASURES: Clinical outcomes included measures of motor function (Gross Motor Function Measure and expanded Hammersmith Functional Motor Scale), pulmonary function (forced vital capacity), and muscle strength (myometry). Participants were evaluated every 2 months for the initial 6 months and every 3 months for the subsequent 6 months. We evaluated change over 12 months for all clinical outcomes and examined potential correlates of change over time including age, sex, SMA type, ambulatory status, SMN2 copy number, medication use, and baseline function. RESULTS: There were no significant changes over 12 months in motor function, pulmonary function, and muscle strength measures. There was evidence of motor function gain in ambulatory patients, especially in those children younger than 5 years. Scoliosis surgery during the observation period led to a subsequent decline in motor function. CONCLUSIONS: Our results confirm previous clinical reports suggesting that SMA types 2 and 3 represent chronic phenotypes that have relatively stable clinical courses. We did not detect any measurable clinical disease progression in SMA types 2 and 3 over 12 months, suggesting that clinical trials will have to be designed to measure improvement rather than stabilization of disease progression.

Muscle volume estimation by magnetic resonance imaging in spinal muscular atrophy.

Thigh muscle volume was assessed using magnetic resonance imaging in 16 subjects with spinal muscular atrophy. Scans were successful for 14 of 16 subjects (1 type 1, 6 type 2, and 7 type 3) as young as 5.7 years. Muscle volume with normal and abnormal signal was measured using blinded, semiautomated analysis of reconstructed data. Results were compared with segmental lean mass estimated by dual-energy X-ray absorptiometry and correlated with clinical and electrophysiological measures of disease severity. Muscle volume was reduced with abnormal signal quality. Test-retest reliability (r = .99) and correlation with dual-energy X-ray absorptiometry (r = .91) were excellent. Type 2 subjects had lower volume (3.5 ± 1.6 vs 6.3 ± 2.8 mL/cm height; P = .06) and higher percentage of muscle with abnormal signal (68% ± 20% vs 47% ± 27%; P = .14) than type 3. Reproducibility, tolerability, and strong correlation with clinical measures make magnetic resonance imaging a candidate biomarker for clinical research.

Functional alpha-1B adrenergic receptors on human epicardial coronary artery endothelial cells.

Alpha-1-adrenergic receptors (α1-ARs) regulate coronary arterial blood flow by binding catecholamines, norepinephrine (NE), and epinephrine (EPI), causing vasoconstriction when the endothelium is disrupted. Among the three α1-AR subtypes (α1A, α1B, and α1D), the α1D subtype predominates in human epicardial coronary arteries and is functional in human coronary smooth muscle cells (SMCs). However, the presence or function of α1-ARs on human coronary endothelial cells (ECs) is unknown. Here we tested the hypothesis that human epicardial coronary ECs express functional α1-ARs. Cultured human epicardial coronary artery ECs were studied using quantitative real-time reverse transcription polymerase chain reaction, radioligand binding, immunoblot, and (3)H-thymidine incorporation. The α1B-subtype messenger ribonucleic acid (mRNA) was predominant in cultured human epicardial coronary ECs (90-95% of total α1-AR mRNA), and total α1-AR binding density in ECs was twice that in coronary SMCs. Functionally, NE and EPI through the α1B subtype activated extracellular signal-regulated kinase (ERK) in ECs, stimulated phosphorylation of EC endothelial nitric oxide synthase (eNOS), and increased deoxyribonucleic acid (DNA) synthesis. These results are the first to demonstrate α1-ARs on human coronary ECs and indicate that the α1B subtype is predominant. Our findings provide another potential mechanism for adverse cardiac effects of drug antagonists that nonselectively inhibit all three α1-AR subtypes.

Adiposity is increased among high-functioning, non-ambulatory patients with spinal muscular atrophy.

The relationship between body composition and function in spinal muscular atrophy (SMA) is poorly understood. 53 subjects with SMA were stratified by type and Hammersmith functional motor scale, expanded score into three cohorts: low-functioning non-ambulatory (type 2 with Hammersmith score < 12, n=19), high-functioning non-ambulatory (type 2 with Hammersmith score > or = 12 or non-ambulatory type 3, n=17), and Ambulatory (n=17). Lean and fat mass was estimated using dual-energy X-ray absorptiometry. Anthropometric data was incorporated to measure fat-free (lean mass in kg/stature in m(2)) and fat (fat mass in kg/stature in m(2)) mass indices, the latter compared to published age and sex norms. Feeding dysfunction among type 2 subjects was assessed by questionnaire. Fat mass index was increased in the high-functioning non-ambulatory cohort (10.4+/-4.5) compared with both the ambulatory (7.2+/-2.1, P=0.013) and low-functioning non-ambulatory (7.6+/-3.1, P=0.040) cohorts. 12 of 17 subjects (71%) in the high-functioning non-ambulatory cohort had fat mass index > 85th percentile for age and gender (connoting "at risk of overweight") versus 9 of 19 subjects (47%) in the low-functioning non-ambulatory cohort and 8 of 17 ambulatory subjects (47%). Despite differences in clinical function, a similar proportion of low functioning (7/18, 39%) and high functioning (2/7, 29%) type 2 subjects reported swallowing or feeding dysfunction. Non-ambulatory patients with relatively high clinical function may be at particular risk of excess adiposity, perhaps reflecting access to excess calories despite relative immobility, emphasizing the importance of individualized nutritional management in SMA.