Nicotine Impairs Smooth Muscle cAMP Signaling and Vascular Reactivity.

OBJECTIVE: This study aimed to determine nicotine's impact on receptor-mediated cyclic adenosine monophosphate (cAMP) synthesis in vascular smooth muscle (VSM). We hypothesize that nicotine impairs ß adrenergic-mediated cAMP signaling in VSM, leading to altered vascular reactivity. METHODS: The effects of nicotine on cAMP signaling and vascular function were systematically tested in aortic VSM cells and acutely isolated aortas from mice expressing the cAMP sensor TEpacVV (Camper), specifically in VSM (e.g., CamperSM). RESULTS: Isoproterenol (ISO)-induced ß-adrenergic production of cAMP in VSM was significantly reduced in cells from second-hand smoke (SHS)-exposed mice and cultured wild-type VSM treated with nicotine. The decrease in cAMP synthesis caused by nicotine was verified in freshly isolated arteries from a mouse that had cAMP sensor expression in VSM (e.g., CamperSM mouse). Functionally, the changes in cAMP signaling in response to nicotine hindered ISO-induced vasodilation, but this was reversed by immediate PDE3 inhibition. CONCLUSIONS: These results imply that nicotine alters VSM ß adrenergic-mediated cAMP signaling and vasodilation, which may contribute to the dysregulation of vascular reactivity and the development of vascular complications for nicotine-containing product users.

Cardiovascular responses of adult male Sprague-Dawley rats following acute organophosphate intoxication and post-exposure treatment with midazolam with or without allopregnanolone.

Recent experimental evidence suggests combined treatment with midazolam and allopregnanolone is more effective than midazolam alone in terminating seizures triggered by acute organophosphate (OP) intoxication. However, there are concerns that combined midazolam and allopregnanolone increases risk of adverse cardiovascular events. To address this, we used telemetry devices to record cardiovascular responses in adult male Sprague-Dawley rats acutely intoxicated with diisopropylfluorophosphate (DFP). Animals were administered DFP (4 mg/kg, sc), followed immediately by atropine (2 mg/kg, i.m.) and 2-PAM (25 mg/kg, i.m.). At 40 min post-exposure, a subset of animals received midazolam (0.65 mg/kg, im); at 50 min, these rats received a second dose of midazolam or allopregnanolone (12 mg/kg, im). DFP significantly increased blood pressure by ~ 80 mmHg and pulse pressure by ~ 34 mmHg that peaked within 12 min. DFP also increased core temperature by ~ 3.5 °C and heart rate by ~ 250 bpm that peaked at ~ 2 h. Heart rate variability (HRV), an index of autonomic function, was reduced by ~ 80%. All acute (within 15 min of exposure) and two-thirds of delayed (hours after exposure) mortalities were associated with non-ventricular cardiac events within 10 min of cardiovascular collapse, suggesting that non-ventricular events should be closely monitored in OP-poisoned patients. Compared to rats that survived DFP intoxication without treatment, midazolam significantly improved recovery of cardiovascular parameters and HRV, an effect enhanced by allopregnanolone. These data demonstrate that midazolam improved recovery of cardiovascular and autonomic function and that the combination of midazolam and allopregnanolone may be a better therapeutic strategy than midazolam alone.

The Novel GlycoPEGylated FGF21 Analog Pegozafermin Activates Human FGF Receptors and Improves Metabolic and Liver Outcomes in Diabetic Monkeys and Healthy Human Volunteers.

Pegozafermin (also known as BIO89-100) is a glycoPEGylated analog of fibroblast growth factor 21 (FGF21) under development to treat nonalcoholic steatohepatitis (NASH) and severe hypertriglyceridemia (SHTG). In cell-based assays, pegozafermin had a similar receptor engagement profile as recombinant FGF21, with approximately eightfold higher potency at fibroblast growth factor receptor 1c (FGFR1c). In diabetic monkeys, once-weekly and once-every-2-weeks regimens of subcutaneous pegozafermin provided rapid and robust benefits for an array of metabolic biomarkers, including triglycerides, cholesterol, fasting glucose, glycated hemoglobin, adiponectin, alanine aminotransferase, food intake, and body weight. In a single ascending dose study in healthy volunteers, subcutaneously administered pegozafermin was associated with statistically significant improvements in triglycerides, low- and high-density lipoprotein-cholesterol, and adiponectin, an insulin-sensitizing and anti-inflammatory adipokine. Pharmacokinetic half-lives ranged from 55 to 100 hours over the clinically relevant dose range, consistent with the expected half-life extension by glycoPEGylation. These findings provide evidence that pegozafermin is a promising candidate molecule for the treatment of patients with NASH or SHTG. SIGNIFICANCE STATEMENT: Fibroblast growth factor 21 (FGF21) is a stress-inducible hormone that has important roles in regulating energy balance and glucose and lipid homeostasis. Studies presented here demonstrate that a novel long-acting FGF21 analog, pegozafermin, has similar pharmacologic properties as FGF21 and that repeated, subcutaneous dosing of pegozafermin in diabetic monkeys and healthy humans improves lipid metabolism, glucose metabolism, weight, and liver transaminases. These results support future development of pegozafermin for the treatment of metabolic diseases, including nonalcoholic steatohepatitis and severe hypertriglyceridemia.

Cardiac Rhythms and Variation in Hibernating Arctic Ground Squirrels.

AbstractThe dramatic decrease in heart rate (HR) during entrance into hibernation is not a mere response to the lowering of core body temperature (Tb) but a highly regulated fall, as the decrease in HR precedes the drop in Tb. This regulated fall in HR is thought to be mediated by increased cardiac parasympathetic activity. Conversely, the sympathetic nervous system is thought to drive the increase of HR during arousal. Despite this general understanding, we lack temporal information on cardiac parasympathetic regulation throughout a complete hibernation bout. The goal of this study was to fill this gap in knowledge by using Arctic ground squirrels implanted with electrocardiogram/temperature telemetry transmitters. Short-term HR variability (root mean square of successive differences [RMSSD]), an indirect measure of cardiac parasympathetic regulation, was calculated in 11 Arctic ground squirrels. RMSSD, normalized as RMSSD/RR interval (RRI), increased fourfold during early entrance (from 0.2±0.1 to 0.8±0.2, P<0.05). RMSSD/RRI peaked after HR dropped by over 90% and Tb fell by 70%. Late entrance was delineated by a decline in RMSSD/RRI while Tb continued to decrease. During arousal, HR started to increase 2 h before Tb, with a concurrent decrease in RMSSD/RRI to a new minimum. As Tb increased to a maximum during interbout arousal, HR declined, and RMSSD/RRI increased. These data suggest that activation of the parasympathetic nervous system initiates and regulates the HR decrease during entrance into hibernation and that withdrawal of parasympathetic activation initiates arousal. We conclude that cardiac parasympathetic regulation persists throughout all phases of a hibernation bout-a feature of the autonomic nervous system's regulation of hibernation that was not appreciated previously.

Effects of chronic secondhand smoke exposure on cardiovascular regulation and the role of soluble epoxide hydrolase in mice.

Background: Secondhand smoke (SHS) is a significant risk factor for cardiovascular morbidity and mortality with an estimated 80% of SHS-related deaths attributed to cardiovascular causes. Public health measures and smoking bans have been successful both in reducing SHS exposure and improving cardiovascular outcomes in non-smokers. Soluble epoxide hydrolase (sEH) inhibitors have been shown to attenuate tobacco exposure-induced lung inflammatory responses, making them a promising target for mitigating SHS exposure-induced cardiovascular outcomes. Objectives: The objectives of this study were to determine 1) effects of environmentally relevant SHS exposure on cardiac autonomic function and blood pressure (BP) regulation and 2) whether prophylactic administration of an sEH inhibitor (TPPU) can reduce the adverse cardiovascular effects of SHS exposure. Methods: Male C57BL/6J mice (11 weeks old) implanted with BP/electrocardiogram (ECG) telemetry devices were exposed to filtered air or 3 mg/m3 of SHS (6 hr/d, 5 d/wk) for 12 weeks, followed by 4 weeks of recovery in filtered air. Some mice received TPPU in drinking water (15 mg/L) throughout SHS exposure. BP, heart rate (HR), HR variability (HRV), baroreflex sensitivity (BRS), and BP variability were determined monthly. Results: SHS exposure significantly decreased 1) short-term HRV by ∼20% (p < 0.05) within 4 weeks; 2) overall HRV with maximum effect at 12 weeks (-15%, p < 0.05); 3) pulse pressure (-8%, p < 0.05) as early as week 4; and 4) BRS with maximum effect at 12 weeks (-11%, p < 0.05). Four weeks of recovery following 12 weeks of SHS ameliorated all SHS-induced cardiovascular detriments. Importantly, mice exposed to TPPU in drinking water during SHS-related exposure were protected from SHS cardiovascular consequences. Discussion: The data suggest that 1) environmental relevant SHS exposure significantly alters cardiac autonomic function and BP regulation; 2) cardiovascular consequences from SHS can be reversed by discontinuing SHS exposure; and 3) inhibiting sEH can prevent SHS-induced cardiovascular consequences.

Opportunities and barriers to translating the hibernation phenotype for neurocritical care.

Targeted temperature management (TTM) is standard of care for neonatal hypoxic ischemic encephalopathy (HIE). Prevention of fever, not excluding cooling core body temperature to 33°C, is standard of care for brain injury post cardiac arrest. Although TTM is beneficial, HIE and cardiac arrest still carry significant risk of death and severe disability. Mammalian hibernation is a gold standard of neuroprotective metabolic suppression, that if better understood might make TTM more accessible, improve efficacy of TTM and identify adjunctive therapies to protect and regenerate neurons after hypoxic ischemia brain injury. Hibernating species tolerate cerebral ischemia/reperfusion better than humans and better than other models of cerebral ischemia tolerance. Such tolerance limits risk of transitions into and out of hibernation torpor and suggests that a barrier to translate hibernation torpor may be human vulnerability to these transitions. At the same time, understanding how hibernating mammals protect their brains is an opportunity to identify adjunctive therapies for TTM. Here we summarize what is known about the hemodynamics of hibernation and how the hibernating brain resists injury to identify opportunities to translate these mechanisms for neurocritical care.

Safety, pharmacokinetics, and pharmacodynamics of pegozafermin in patients with non-alcoholic steatohepatitis: a randomised, double-blind, placebo-controlled, phase 1b/2a multiple-ascending-dose study.

BACKGROUND: Management strategies for non-alcoholic steatohepatitis (NASH) are based predominantly on lifestyle modification, with no approved disease-modifying drugs yet available. We aimed to evaluate the safety, pharmacokinetics, and pharmacodynamics of pegozafermin (BIO89-100), a glycoPEGylated FGF21 analogue, in participants with NASH. METHODS: This randomised, double-blind, placebo-controlled, phase 1b/2a multiple-ascending-dose study enrolled adults (aged 21-75 years) who had NASH with stage F1-F3 fibrosis, or non-alcoholic fatty liver disease and a high risk of NASH (referred to in this study as phenotypic NASH) due to central obesity with type 2 diabetes, or central obesity with increased alanine aminotransferase (ALT) or a Fibroscan score of 7 kPa or greater, across 12 specialist centres and clinics in the USA. Patients were centrally randomised by use of an interactive web response system to receive subcutaneously administered pegozafermin (3, 9, 18, or 27 mg once weekly; 18 or 36 mg once every 2 weeks) or placebo for 12 weeks. The primary endpoints were the safety, tolerability, and pharmacokinetics of pegozafermin. This trial is registered with ClinicalTrials.gov (NCT04048135). FINDINGS: Between July 29, 2019, and Aug 3, 2020, 275 participants were screened and 81 (15 [19%] with biopsy-confirmed NASH) were randomly assigned: 62 to pegozafermin (six to 3 mg once weekly, 12 to 9 mg once weekly, 11 to 18 mg once weekly, ten to 27 mg once weekly, 14 to 18 mg once every 2 weeks, and nine to 36 mg once every 2 weeks) and 19 to placebo; 63 received pegozafermin and 18 received placebo, as one participant in the placebo group inadvertently received 3 mg pegozafermin once weekly. Adverse events were reported in eight (44%) of 18 participants in the pooled placebo group, six (86%) of seven in the 3 mg once weekly pegozafermin group, four (33%) of 12 in the 9 mg once weekly group, seven (64%) of 11 in the 18 mg once weekly group, seven (70%) of ten in the 27 mg once weekly group, eight (57%) of 14 in the 18 mg once every 2 weeks group, and eight (89%) of nine in the 36 mg once every 2 weeks group. The most common treatment-related adverse event was mild increased appetite (in ten [16%] of 63 participants in the pooled pegozafermin group vs none of 18 in the pooled placebo group), which was not associated with bodyweight gain. Two patients discontinued treatment due to an adverse event (one each in the 27 mg once weekly and 18 mg once every 2 weeks groups). No treatment-related serious adverse events or deaths occurred. Dose-proportional pharmacokinetics were observed. Anti-drug antibodies were detected in 41 (65%) of 63 participants treated with pegozafermin. By week 13, pegozafermin significantly reduced the least squares mean (LSM) absolute differences in hepatic fat fraction versus pooled placebo (-8·9% [95% CI -14·8 to -3·1; p=0·0032] for 3 mg once weekly, -11·5% [-16·1 to -6·9; p<0·0001] for 9 mg once weekly, -8·9% [-13·7 to -4·2; p=0·0004] for 18 mg once weekly, -14·9% [-20·1 to -9·7; p<0·0001] for 27 mg once weekly, -10·4% [-14·7 to -6·1; p<0·0001] for 18 mg once every 2 weeks, and -11·1% [-16·2 to -6·0; p<0·0001] for 36 mg once every 2 weeks). At week 13, significant LSM relative reductions versus pooled placebo in ALT were observed for pegozafermin 9 mg once weekly, 18 mg once weekly, 27 mg once weekly, and 36 mg once every 2 weeks. At week 13, significant LSM relative reductions versus pooled placebo in aspartate aminotransferase were observed for pegozafermin 3 mg once weekly, 27 mg once weekly, and 36 mg once every 2 weeks. Significant improvements were also observed with pegozafermin treatment for triglycerides (9 mg once weekly, 27 mg once weekly, and 18 mg once every 2 weeks), LDL-C (9 mg once weekly and 27 mg once weekly), HDL-C (3 mg once weekly and 18 mg once every 2 weeks), non-HDL-C (9 mg once weekly and 27 mg once weekly), adiponectin (all doses except for 36 mg once every 2 weeks), PRO-C3 (27 mg once weekly), and bodyweight (27 mg once weekly). Changes in insulin resistance and HbA1c were not significant. INTERPRETATION: Pegozafermin was generally well tolerated and associated with clinically meaningful reductions in liver fat, measures of liver function, and circulating lipids. Further evaluation of pegozafermin in individuals with NASH is warranted. FUNDING: 89bio.

Secondhand Smoke Decreased Excitability and Altered Action Potential Characteristics of Cardiac Vagal Neurons in Mice.

Background: Secondhand smoke (SHS), a major indoor pollutant, is a significant risk factor for cardiovascular morbidity and mortality including arrhythmias and sudden cardiac death. Exposure to SHS can produce autonomic imbalance, as evidenced by reduced heart rate variability (HRV)-a clinical metric of cardiac vagal regulation. Currently, the mechanisms through which SHS changes the vagal preganglionic neuronal inputs to the heart to produce this remains unknown. Objectives: To characterize the effect of SHS on both the excitability and action potential (AP) characteristics of anatomically identified cardiac vagal neurons (CVNs) in the nucleus ambiguus and examine whether SHS alters small conductance calcium-activated potassium (SK) channel activity of these CVNs. Methods: Adult male mice were exposed to four weeks of filtered air or SHS (3 mg/m3) 6 h/day, 5 day/week. Using patch-clamp recordings on identified CVNs in brainstem slices, we determined neuronal excitability and AP characteristics with depolarizing step- and ramp-current injections. Results: Four weeks of SHS exposure reduced spiking responses to depolarizing current injections and increased AP voltage threshold in CVNs. Perfusion with apamin (20 nM) magnified these SHS-induced effects, suggesting reduced SK channel activity may serve to minimize the SHS-induced decreases in CVNs excitability. Medium afterhyperpolarization (a measurement of SK channel activity) was smaller in the SHS group, further supporting a lower SK channel activity. AP amplitude, rise rate, fast afterhyperpolarization amplitude (a measurement of voltage-gated channel activity), and decay rate were higher in the SHS group at membrane voltages more positive to 0 mV, suggesting altered inactivation properties of voltage-dependent channels underlying APs. Discussion: SHS exposure reduced neuronal excitability of CVNs with compensatory attenuation of SK channel activity and altered AP characteristics. Neuroplasticity of CVNs could blunt regulatory cardiac vagal signaling and contribute to the cardiovascular consequences associated with SHS exposure, including reduced HRV.

Secondhand Smoke Exposure Impairs Ion Channel Function and Contractility of Mesenteric Arteries.

Cigarette smoke, including secondhand smoke (SHS), has significant detrimental vascular effects, but its effects on myogenic tone of small resistance arteries and the underlying mechanisms are understudied. Although it is apparent that SHS contributes to endothelial dysfunction, much less is known about how this toxicant alters arterial myocyte contraction, leading to alterations in myogenic tone. The study's goal is to determine the effects of SHS on mesenteric arterial myocyte contractility and excitability. C57BL/6J male mice were randomly assigned to either filtered air (FA) or SHS (6 h/d, 5 d/wk) exposed groups for a 4, 8, or 12-weeks period. Third and fourth-order mesenteric arteries and arterial myocytes were acutely isolated and evaluated with pressure myography and patch clamp electrophysiology, respectively. Myogenic tone was found to be elevated in mesenteric arteries from mice exposed to SHS for 12 wk but not for 4 or 8 wk. These results were correlated with an increase in L-type Ca2+ channel activity in mesenteric arterial myocytes after 12 wk of SHS exposure. Moreover, 12 wk SHS exposed arterial myocytes have reduced total potassium channel current density, which correlates with a depolarized membrane potential (Vm). These results suggest that SHS exposure induces alterations in key ionic conductances that modulate arterial myocyte contractility and myogenic tone. Thus, chronic exposure to an environmentally relevant concentration of SHS impairs mesenteric arterial myocyte electrophysiology and myogenic tone, which may contribute to increased blood pressure and risks of developing vascular complications due to passive exposure to cigarette smoke.

Dietary management and major clinical events in patients with long-chain fatty acid oxidation disorders enrolled in a phase 2 triheptanoin study.

BACKGROUND & AIMS: Long-chain fatty acid oxidation disorders (LC-FAOD) are rare, life-threatening, autosomal recessive disorders that lead to energy depletion and major clinical events (MCEs), such as acute metabolic crises of hypoglycemia, cardiomyopathy, and rhabdomyolysis. The aim of this study was to report a post hoc analysis of diet diary data from the phase 2 UX007-CL201 study (NCT01886378). METHODS: In the single-arm, open-label, phase 2 UX007-CL201 study, the safety and efficacy of 78 weeks of treatment with triheptanoin, an odd-carbon, medium-chain triglyceride consisting of three 7-carbon fatty acids on a glycerol backbone, was investigated in subjects with LC-FAOD versus a retrospective 78-week period when subjects were optimally managed under published dietary guidelines. Subject dietary reports were collected to analyze the relationship between diet, triheptanoin treatment, and MCEs. Referring metabolic physicians completed a survey on patient management and clinical outcomes before and after initiation of triheptanoin. Before initiating triheptanoin, subjects received a mean daily caloric intake (DCI) of 17.4% from medium-chain triglycerides (MCT). During the study, subjects received a mean of 27.5% DCI from triheptanoin. Protein (13.7% vs 14.5% DCI), long-chain fat (13.1% vs 10.5% DCI), and carbohydrate (55.3% vs 47.1% DCI) intake were consistent between the pre-triheptanoin and triheptanoin treatment periods, respectively. RESULTS: Following 78 weeks of treatment, mean annualized MCE rate decreased by 48.1% (p = 0.021) and mean annualized MCE event-day rate decreased by 50.3% (p = 0.028). A weak association existed between improvement in annualized MCE rate and change in percent DCI from MCT (Spearman rank correlation: r = -0.38; 95% CI: -0.675, 0.016). However, there was large variability in the association and no specific pattern of change for larger or smaller changes in dose. Seventy-two percent of physicians reported that triheptanoin had a clinically meaningful benefit on medical management of their patients. CONCLUSIONS: Treatment with triheptanoin at the protocol-specified dose decreased the rate of MCEs in patients with LC-FAOD independently from other dietary changes between the pre-triheptanoin and triheptanoin treatment periods. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01886378.

CRL5-dependent regulation of the small GTPases ARL4C and ARF6 controls hippocampal morphogenesis.

The small GTPase ARL4C participates in the regulation of cell migration, cytoskeletal rearrangements, and vesicular trafficking in epithelial cells. The ARL4C signaling cascade starts by the recruitment of the ARF-GEF cytohesins to the plasma membrane, which, in turn, bind and activate the small GTPase ARF6. However, the role of ARL4C-cytohesin-ARF6 signaling during hippocampal development remains elusive. Here, we report that the E3 ubiquitin ligase Cullin 5/RBX2 (CRL5) controls the stability of ARL4C and its signaling effectors to regulate hippocampal morphogenesis. Both RBX2 knockout and Cullin 5 knockdown cause hippocampal pyramidal neuron mislocalization and development of multiple apical dendrites. We used quantitative mass spectrometry to show that ARL4C, Cytohesin-1/3, and ARF6 accumulate in the RBX2 mutant telencephalon. Furthermore, we show that depletion of ARL4C rescues the phenotypes caused by Cullin 5 knockdown, whereas depletion of CYTH1 or ARF6 exacerbates overmigration. Finally, we show that ARL4C, CYTH1, and ARF6 are necessary for the dendritic outgrowth of pyramidal neurons to the superficial strata of the hippocampus. Overall, we identified CRL5 as a key regulator of hippocampal development and uncovered ARL4C, CYTH1, and ARF6 as CRL5-regulated signaling effectors that control pyramidal neuron migration and dendritogenesis.

Growth Curves for Children with X-linked Hypophosphatemia.

CONTEXT: We characterized linear growth in infants and children with X-linked hypophosphatemia (XLH). OBJECTIVE: Provide linear growth curves for children with XLH from birth to early adolescence. DESIGN: Data from 4 prior studies of XLH were pooled to construct growth curves. UX023-CL002 was an observational, retrospective chart review. Pretreatment data were collected from 3 interventional trials: two phase 2 trials (UX023-CL201, UX023-CL205) and a phase 3 trial (UX023-CL301). SETTING: Medical centers with expertise in treating XLH. PATIENTS: Children with XLH, 1-14 years of age. INTERVENTION: None. MAIN OUTCOME MEASURE: Height-for-age linear growth curves, including values for the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles for children with XLH compared to population norms. RESULTS: A total of 228 patients (132 girls, 96 boys) with 2381 height measurements were included. Nearly all subjects (> 99%) reported prior management with supplementation therapy. Compared to the Center for Disease Control and Prevention growth curves, boys at age 3 months, 6 months, 9 months, 1 year, and 2 years had median height percentiles of 46%, 37%, 26%, 18%, and 5%, respectively; for girls the median height percentiles were 52%, 37%, 25%, 18%, and 7%, respectively. Annual growth in children with XLH fell below that of healthy children near 1 year of age and progressively declined during early childhood, with all median height percentiles < 8% between 2 and 12 years old. CONCLUSION: Children with XLH show decreased height gain by 1 year of age and remain below population norms thereafter. These data will help evaluate therapeutic interventions on linear growth for pediatric XLH.

Device profile of the MobiusHD EVBA system for the treatment of resistant hypertension: overview of its mechanism of action, safety and efficacy.

INTRODUCTION: Early promising results of renal nerve denervation awakened interest in developing medical device alternatives for patients with resistant hypertension. The subsequent sham-controlled renal nerve denervation randomized trials were disappointing leading researchers and innovators to explore alternative device and trial designs to address this significant unmet need. We describe the innovation process leading to the first endovascular carotid baroreflex amplification device currently undergoing clinical trials in the United States and Europe. AREAS COVERED: We provide a brief overview of carotid baroreceptor physiology and then couple this knowledge with the fundamental principles of strain pattern changes that led to the proposed innovation. The mechanism of blood pressure reduction via enhancing innate physiologic carotid sinus baroreceptor signaling through changes in pulsatile focal carotid bulb strain is described alongside preclinical testing and early clinical results. EXPERT OPINION: The collective data to date suggest endovascular carotid baroreflex amplification may be an innovative alternative for resistant hypertension patients. However, well-controlled studies will be needed to assess efficacy, safety, durability, and risk: benefit of this permanent intravascular carotid implant. SUBJECT CODES: high blood pressure, hypertension, treatment, physiology.

Cardiopulmonary Health Effects of Airborne Particulate Matter: Correlating Animal Toxicology to Human Epidemiology.

The effects of particulate matter (PM) on cardiopulmonary health have been studied extensively over the past three decades. Particulate matter is the primary criteria air pollutant most commonly associated with adverse health effects on the cardiovascular and respiratory systems. The mechanisms by which PM exerts its effects are thought to be due to a variety of factors which may include, but are not limited to, concentration, duration of exposure, and age of exposed persons. Adverse effects of PM are strongly driven by their physicochemical properties, sites of deposition, and interactions with cells of the respiratory and cardiovascular systems. The direct translocation of particles, as well as neural and local inflammatory events, are primary drivers for the observed cardiopulmonary health effects. In this review, toxicological studies in animals, and clinical and epidemiological studies in humans are examined to demonstrate the importance of using all three approaches to better define potential mechanisms driving health outcomes upon exposure to airborne PM of diverse physicochemical compositions.

Individual heat map assessments demonstrate vestronidase alfa treatment response in a highly heterogeneous mucopolysaccharidosis VII study population.

Mucopolysaccharidosis (MPS) VII is an ultra-rare, progressively debilitating, life-threatening lysosomal disease caused by deficiency of the enzyme, ß-glucuronidase. Vestronidase alfa is an approved enzyme replacement therapy for MPS VII. UX003-CL301 was a phase 3, randomized, placebo-controlled, blind-start study examining the efficacy and safety of vestronidase alfa 4 mg/kg intravenously administered every 2 weeks to 12 patients with MPS VII. Due to the rarity of disease, broad eligibility criteria resulted in a highly heterogeneous population with variable symptoms. For an integrated view of the diverse data, the changes from baseline (or randomization for the placebo period) in clinical endpoints were grouped into three functional domains (mobility, fatigue, and fine motor + self-care) and analyzed post-hoc as subject-level heat maps. Mobility assessments included the 6-minute walk test, 3-minute stair climb test, Bruininks-Oseretsky test (BOT-2) gross motor function subtests, and patient-reported outcome assessments (PROs) related to movement, pain, and ambulation. Fatigue assessments included the Pediatric Quality of Life Multidimensional Fatigue Scale and other fatigue-related PROs. Fine motor + self-care assessments included BOT-2 fine motor function subtests and PROs for eating, dressing, hygiene, and caregiver assistance. Most subjects showed improvement in at least one domain. Two subjects improved in two or more domains and two subjects did not show clear improvement in any domain. Both severely and mildly affected subjects improved with vestronidase alfa in clinical assessments, PRO results, or both. Heat map analysis demonstrates how subjects responded to treatment across multiple domains, providing a useful visual tool for studying rare diseases with variable symptoms.

The Use of Percent Change in RR Interval for Data Exclusion in Analyzing 24-h Time Domain Heart Rate Variability in Rodents.

While epidemiological data support the link between reduced heart rate variability (HRV) and a multitude of pathologies, the mechanisms underlying changes in HRV and disease progression are poorly understood. Even though we have numerous rodent models of disease for mechanistic studies, not being able to reliably measure HRV in conscious, freely moving rodents has hindered our ability to extrapolate the role of HRV in the progression from normal physiology to pathology. The sheer number of heart beats per day (>800,000 in mice) makes data exclusion both time consuming and daunting. We sought to evaluate an RR interval exclusion method based on percent (%) change of adjacent RR intervals. Two approaches were evaluated: % change from "either" and "both" adjacent RR intervals. The data exclusion method based on standard deviation (SD) was also evaluated for comparison. Receiver operating characteristic (ROC) curves were generated to determine the performance of each method. Results showed that exclusion based on % change from "either" adjacent RR intervals was the most accurate method in identifying normal and abnormal RR intervals, with an overall accuracy of 0.92-0.99. As the exclusion value increased (% change or SD), the sensitivity (correctly including normal RR intervals) increased exponentially while the specificity (correctly rejecting abnormal RR intervals) decreased linearly. Compared to the SD method, the "either" approach had a steeper rise in sensitivity and a more gradual decrease in specificity. The intersection of sensitivity and specificity where the exclusion criterion had the same accuracy in identifying normal and abnormal RR intervals was 10-20% change for the "either" approach and ∼ 1 SD for the SD-based exclusion method. Graphically (tachogram and Lorenz plot), 20% change from either adjacent RR interval resembled the data after manual exclusion. Finally, overall (SDNN) and short-term (rMSSD) indices of HRV generated using 20% change from "either" adjacent RR intervals as the exclusion criterion were closer to the manual exclusion method with lower subject-to-subject variability than those generated using the 2 SD exclusion criterion. Thus, 20% change from "either" adjacent RR intervals is a good criterion for data exclusion for reliable 24-h time domain HRV analysis in rodents.

Burosumab versus conventional therapy in children with X-linked hypophosphataemia: a randomised, active-controlled, open-label, phase 3 trial.

BACKGROUND: X-linked hypophosphataemia in children is characterised by elevated serum concentrations of fibroblast growth factor 23 (FGF23), hypophosphataemia, rickets, lower extremity bowing, and growth impairment. We compared the efficacy and safety of continuing conventional therapy, consisting of oral phosphate and active vitamin D, versus switching to burosumab, a fully human monoclonal antibody against FGF23, in paediatric X-linked hypophosphataemia. METHODS: In this randomised, active-controlled, open-label, phase 3 trial at 16 clinical sites, we enrolled children with X-linked hypophosphataemia aged 1-12 years. Key eligibility criteria were a total Thacher rickets severity score of at least 2·0, fasting serum phosphorus lower than 0·97 mmol/L (3·0 mg/dL), confirmed PHEX (phosphate-regulating endopeptidase homolog, X-linked) mutation or variant of unknown significance in the patient or a family member with appropriate X-linked dominant inheritance, and receipt of conventional therapy for at least 6 consecutive months for children younger than 3 years or at least 12 consecutive months for children older than 3 years. Eligible patients were randomly assigned (1:1) to receive either subcutaneous burosumab starting at 0·8 mg/kg every 2 weeks (burosumab group) or conventional therapy prescribed by investigators (conventional therapy group). Both interventions lasted 64 weeks. The primary endpoint was change in rickets severity at week 40, assessed by the Radiographic Global Impression of Change global score. All patients who received at least one dose of treatment were included in the primary and safety analyses. The trial is registered with ClinicalTrials.gov, number NCT02915705. FINDINGS: Recruitment took place between Aug 3, 2016, and May 8, 2017. Of 122 patients assessed, 61 were enrolled. Of these, 32 (18 girls, 14 boys) were randomly assigned to continue receiving conventional therapy and 29 (16 girls, 13 boys) to receive burosumab. For the primary endpoint at week 40, patients in the burosumab group had significantly greater improvement in Radiographic Global Impression of Change global score than did patients in the conventional therapy group (least squares mean +1·9 [SE 0·1] with burosumab vs +0·8 [0·1] with conventional therapy; difference 1·1, 95% CI 0·8-1·5; p<0·0001). Treatment-emergent adverse events considered possibly, probably, or definitely related to treatment by the investigator occurred more frequently with burosumab (17 [59%] of 29 patients in the burosumab group vs seven [22%] of 32 patients in the conventional therapy group). Three serious adverse events occurred in each group, all considered unrelated to treatment and resolved. INTERPRETATION: Significantly greater clinical improvements were shown in rickets severity, growth, and biochemistries among children with X-linked hypophosphataemia treated with burosumab compared with those continuing conventional therapy. FUNDING: Ultragenyx Pharmaceutical and Kyowa Kirin International.

Results from a 78-week, single-arm, open-label phase 2 study to evaluate UX007 in pediatric and adult patients with severe long-chain fatty acid oxidation disorders (LC-FAOD).

Long-chain fatty acid oxidation disorders (LC-FAOD) are rare disorders characterized by acute crises of energy metabolism and severe energy deficiency that may present with cardiomyopathy, hypoglycemia, and/or rhabdomyolysis, which can lead to frequent hospitalizations and early death. An open-label Phase 2 study evaluated the efficacy of UX007, an investigational odd-carbon medium-chain triglyceride, in 29 subjects with severe LC-FAOD. UX007 was administered over 78 weeks at a target dose of 25-35% total daily caloric intake (mean 27.5%). The frequency and duration of major clinical events (hospitalizations, emergency room visits, and emergency home interventions due to rhabdomyolysis, hypoglycemia, and cardiomyopathy) occurring during 78 weeks of UX007 treatment was compared with the frequency and duration of events captured retrospectively from medical records for 78 weeks before UX007 initiation. The mean annualized event rates decreased from 1.69 to 0.88 events/year following UX007 initiation (p = 0.021; 48.1% reduction). The mean annualized duration rate decreased from 5.96 to 2.96 days/year (p = 0.028; 50.3% reduction). Hospitalizations due to rhabdomyolysis, the most common event, decreased from 1.03 to 0.63 events/year (p = 0.104; 38.7% reduction). Initiation of UX007 eliminated hypoglycemia events leading to hospitalization (from 11 pre-UX007 hospitalizations, 0.30 events/year vs. 0; p = 0.067) and intensive care unit (ICU) care (from 2 pre-UX007 ICU admissions, 0.05 events/year vs. 0; p = 0.161) and reduced cardiomyopathy events (3 events vs. 1 event; 0.07 to 0.02 events/year; 69.7% decrease). The majority of treatment-related adverse events (AEs) were mild to moderate gastrointestinal symptoms, including diarrhea, vomiting, and abdominal or gastrointestinal pain, which can be managed with smaller, frequent doses mixed with food.

Rickets severity predicts clinical outcomes in children with X-linked hypophosphatemia: Utility of the radiographic Rickets Severity Score.

The Rickets Severity Score (RSS) was used to evaluate X-linked hypophosphatemic rickets (XLH), a genetic disorder mediated by increased circulating FGF23. The reliability of the RSS was assessed using data from a randomized, phase 2 clinical trial that evaluated the effects of burosumab, a fully human anti-FGF23 monoclonal antibody, in 52 children with XLH ages 5 to 12 years. Bilateral knee and wrist radiographs were obtained at baseline, week 40, and week 64. We evaluated the relationships of the RSS to the Radiographic Global Impression of Change (RGI-C), serum alkaline phosphatase (ALP), height Z-score, 6-minute walk test (6MWT) percent predicted, and the Pediatric Orthopedic Society of North America Pediatric Outcomes Data Collection Instrument (POSNA-PODCI). The RSS showed moderate-to-substantial inter-rater reliability (weighted kappa, 0.45-0.65; Pearson correlation coefficient (r), 0.83-0.89) and substantial intra-rater reliability (weighted Kappa, 0.66; r = 0.91). Baseline RSS correlated with serum ALP (r = 0.47). Baseline RSS identified two subgroups (higher [RSS ≥1.5] and lower RSS [RSS <1.5]) that discriminated between subjects with greater and lesser rachitic disease. Higher RSS was associated with more severe clinical features, including impaired growth (Z-score, -2.12 vs -1.44) and walking ability (6MWT percent predicted, 77% vs 86%), more severe self-reported pain (29.9 [more severe] vs 45.3 [less severe]) and less physical function (29.6 [more severe] vs 40.9 [less severe]). During burosumab treatment, greater reductions in RSS corresponded to higher RGI-C global scores (r = -0.65). Improvements in RSS correlated with decreased serum ALP (r = 0.47). These results show the reliability of the RSS in XLH, and demonstrate that higher RSS values are associated with greater biochemical, clinical, and functional impairments in children with XLH.