Appetite-suppressant drugs and the risk of primary pulmonary hypertension. International Primary Pulmonary Hypertension Study Group

Cardiovascular safety of low-dose fenfluramine in Dravet syndrome: a review of its benefit-risk profile in a new patient population

OBJECTIVE

Dravet syndrome (DS) is a rare, treatment-resistant epilepsy syndrome for which current treatment regimens are often ineffective. Fenfluramine is currently in development for treatment of DS, based on reports in the 1980s and 1990s of its anti-epileptic activity in pediatric patients with intractable epilepsy. However, fenfluramine was withdrawn from global markets in 1997 following reports of its association with pulmonary hypertension and heart valve disease in adult patients treated for obesity. This review was conducted to assess cardiac safety of fenfluramine when used at lower doses for treatment of DS.

METHODS

Pubmed was searched for clinical studies of fenfluramine in obese adults who reported incidence of heart valve disease. These data were reviewed against published results from Belgian patients with DS who have been treated with low-dose fenfluramine for up to 28 years.

RESULTS

Nine controlled studies of fenfluramine and related compounds (dexfenfluramine and/or phentermine) which assessed incidence and severity of cardiac valve disease in 3,268 treated patients and 2,017 control subjects have been reported. Mild or greater aortic valve regurgitation was found in 9.6% of treated patients compared with 3.9% of control subjects, and moderate or greater mitral valve regurgitation was found in 3.1% of treated patients and 2.5% of control subjects. Nineteen DS patients have been treated for up to 28 years with 10-20 mg/day fenfluramine, with no clinical signs or symptoms of cardiac valve disease or pulmonary hypertension. Slight and clinically unimportant changes in valve structure have been seen on echocardiography in five patients at some time during the observation period.

CONCLUSIONS

A different benefit-risk relationship appears to be emerging when fenfluramine is used at low doses for extended periods in young patients with DS. Continued cardiac assessments during ongoing Phase 3 clinical trials will provide additional safety information for this potential new and effective treatment.

Current and emerging pharmacotherapies for obesity in Australia

BACKGROUND

Obesity is a major issue in Australia and globally. Many individuals struggle to maintain weight loss with lifestyle modification, and adjunctive pharmacotherapy may help. Historically, there have been limited pharmacotherapies for managing obesity. In addition, previous treatments such as phentermine-fenfluramine, rimonabant and sibutramine were withdrawn due to safety issues, resulting in lingering safety concerns.

METHODS

This is a narrative review of published data examining four new pharmacotherapy options for weight management in Australia. Of four new therapeutic options, three may be approved in Australia shortly and one - liraglutide 3.0mg - was approved in December 2015. Liraglutide is a glucagon-like peptide-1 receptor agonist that appears to act by increasing satiety and reducing food intake. Lorcaserin is a selective agonist of the serotonin_2C receptor, which mediates anorectic activity. The naltrexone/bupropion extended release (ER) combination utilises synergistic effects of the two component drugs, mediated via neurons in the hypothalamus, to reduce energy intake. Phentermine/topiramate ER combines the appetite suppressant phentermine with topiramate, an anti-epileptic with appetite-suppressant effects. All can result in meaningful improvements in obesity-related diseases, including diabetes and cardiovascular disorders) in large phase 3 trials, with efficacy demonstrated over 3 years for liraglutide 3.0 mg and 1-2 years for the rest.

CONCLUSIONS

The landscape of obesity treatment is changing rapidly. Of the new therapeutic options presented, all options have associated adverse events requiring long-term safety data, but the availability of new options is a welcome development.

S-phenylpiracetam, a selective DAT inhibitor, reduces body weight gain without influencing locomotor activity

S-phenylpiracetam is an optical isomer of phenotropil, which is a clinically used nootropic drug that improves physical condition and cognition. Recently, it was shown that S-phenylpiracetam is a selective dopamine transporter (DAT) inhibitor that does not influence norepinephrine (NE) or serotonin (5-HT) receptors. The aim of the present study was to study the effects of S-phenylpiracetam treatment on body weight gain, blood glucose and leptin levels, and locomotor activity. Western diet (WD)-fed mice and obese Zucker rats were treated daily with peroral administration of S-phenylpiracetam for 8 and 12weeks, respectively. Weight gain and plasma metabolites reflecting glucose metabolism were measured. Locomotor activity was detected in an open-field test. S-phenylpiracetam treatment significantly decreased body weight gain and fat mass increase in the obese Zucker rats and in the WD-fed mice. In addition, S-phenylpiracetam reduced the plasma glucose and leptin concentration and lowered hyperglycemia in a glucose tolerance test in both the mice and the rats. S-phenylpiracetam did not influence locomotor activity in the obese Zucker rats or in the WD-fed mice. The results demonstrate that S-phenylpiracetam reduces body weight gain and improves adaptation to hyperglycemia without stimulating locomotor activity. Our findings suggest that selective DAT inhibitors, such as S-phenylpiracetam, could be potentially useful for treating obesity in patients with metabolic syndrome with fewer adverse health consequences compared to other anorectic agents.

Reduced carboxylesterase 1 is associated with endothelial injury in methamphetamine-induced pulmonary arterial hypertension

Pulmonary arterial hypertension is a complication of methamphetamine use (METH-PAH), but the pathogenic mechanisms are unknown. Given that cytochrome P450 2D6 (CYP2D6) and carboxylesterase 1 (CES1) are involved in metabolism of METH and other amphetamine-like compounds, we postulated that loss of function variants could contribute to METH-PAH. Although no difference in CYP2D6 expression was seen by lung immunofluorescence, CES1 expression was significantly reduced in endothelium of METH-PAH microvessels. Mass spectrometry analysis showed that healthy pulmonary microvascular endothelial cells (PMVECs) have the capacity to both internalize and metabolize METH. Furthermore, whole exome sequencing data from 18 METH-PAH patients revealed that 94.4% of METH-PAH patients were heterozygous carriers of a single nucleotide variant (SNV; rs115629050) predicted to reduce CES1 activity. PMVECs transfected with this CES1 variant demonstrated significantly higher rates of METH-induced apoptosis. METH exposure results in increased formation of reactive oxygen species (ROS) and a compensatory autophagy response. Compared with healthy cells, CES1-deficient PMVECs lack a robust autophagy response despite higher ROS, which correlates with increased apoptosis. We propose that reduced CES1 expression/activity could promote development of METH-PAH by increasing PMVEC apoptosis and small vessel loss.

Mazindol: a risk factor for pulmonary arterial hypertension?

Mazindol is an imidazo-isoindole derivative, a tricyclic compound and a non-amphetamine central nervous system stimulant that blocks dopamine and norepinephrine reuptake. Mazindol was withdrawn from the US and European markets in 1999 for reasons unrelated to its efficacy or safety around a time when other anorexic drugs were found to be associated with the development of pulmonary arterial hypertension (PAH). Despite the use of mazindol for decades, reports of PAH due to mazindol intake have been extremely rare. Recent interest on mazindol has emerged for the treatment of narcolepsy and attention-deficit/hyperactivity disorder. Therefore, an updated understanding of the potential benefits and risks of mazindol in these patient populations is warranted.

In vitro and in vivo evaluation of dasatinib and imatinib on physiological parameters of pulmonary arterial hypertension

PURPOSE

Pulmonary arterial hypertension (PAH) results from occlusion or vasoconstriction of pulmonary vessels, leading to progressive right ventricular failure. Dasatinib, a BCR-ABL1 tyrosine kinase inhibitor (TKI) approved for the treatment of chronic myelogenous leukemia, has been associated with PAH. In contrast, the BCR-ABL1 TKI imatinib has demonstrated anti-vasoproliferative properties and has been investigated as a potential treatment for PAH. Here we describe studies evaluating the effects of dasatinib and imatinib on cardiovascular and pulmonary functions to understand the reported differential consequences of the two TKIs in a clinical setting.

METHODS

The direct effects of dasatinib and imatinib were explored in vivo to investigate possible mechanisms of dasatinib-induced PAH. In addition, effects of dasatinib and imatinib on PAH-related mediators were evaluated in vitro.

RESULTS

In rats, both TKIs increased plasma nitric oxide (NO), did not induce PAH-related structural or molecular changes in PA or lungs, and did not alter hemodynamic lung function compared with positive controls. Similarly, in the pulmonary artery endothelial cells and smooth muscle cells co-culture model, imatinib and dasatinib increased NO and decreased endothelin-1 protein and mRNA.

CONCLUSIONS

The results of these studies indicated that dasatinib did not induce physiological changes or molecular signatures consistent with PAH when compared to positive controls. Instead, dasatinib induced changes consistent with imatinib. Both dasatinib and imatinib induced biochemical and structural changes consistent with a protective effect for PAH. These data suggest that other factors of unclear etiology contributed to the development of PAH in patients treated with dasatinib.

Progress report on new antiepileptic drugs: A summary of the Thirteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIII)

The Thirteenth Eilat Conference on New Antiepileptic Drugs and Devices (EILAT XIII) took place in Madrid, Spain, on June 26-29, 2016, and was attended by >200 delegates from 31 countries. The present Progress Report provides an update on experimental and clinical results for drugs presented at the Conference. Compounds for which summary data are presented include an AED approved in 2016 (brivaracetam), 12 drugs in phase I-III clinical development (adenosine, allopregnanolone, bumetanide, cannabidiol, cannabidivarin, 2-deoxy-d-glucose, everolimus, fenfluramine, huperzine A, minocycline, SAGE-217, and valnoctamide) and 6 compounds or classes of compounds for which only preclinical data are available (bumetanide derivatives, sec-butylpropylacetamide, FV-082, 1OP-2198, NAX 810-2, and SAGE-689). Overall, the results presented at the Conference show that considerable efforts are ongoing into discovery and development of AEDs with potentially improved therapeutic profiles compared with existing agents. Many of the drugs discussed in this report show innovative mechanisms of action and many have shown promising results in patients with pharmacoresistant epilepsies, including previously neglected rare and severe epilepsy syndromes.

Pulmonary arterial hypertension associated with interferon therapy: a population-based study

BACKGROUND

Isolated cases of pulmonary arterial hypertension (PAH) with interferon α or β therapy have been reported, but no population-based estimates of the incidence of the disease after interferon exposure are available. The aim of this study was to determine the incidence of PAH after initiation of interferon therapy, using a large commercial insurance database.

METHODS

Using National Drug Codes (NDCs) and Healthcare Common Procedure Coding System (HCPCS) codes, we utilized the Clinformatics™ Data Mart (CDM) database to identify subjects between 20 and 65 years old who received α or β interferon therapy between April 2001 and December 2012. Patients were followed from one year prior to the first medication claim for interferon to the first diagnosis of pulmonary hypertension using ICD-9-CM codes 416.0 and 416.8, or disenrollment. In those subjects diagnosed with pulmonary hypertension, a prescription for PAH-specific medications was used as a surrogate endpoint.

RESULTS

We identified 20,113 subjects who received interferon therapy during the study period. The median follow-up was 20 months. Pulmonary hypertension occurred in 71 subjects, and PAH-specific medications were prescribed to 7 of these subjects.

CONCLUSION

Although our analysis showed that the development of PAH is a rare event with interferon therapy, the risk of developing the disease is several fold higher than that for the general population.

Drug-Induced Pulmonary Hypertension: The First 50 Years

Drug-induced pulmonary arterial hypertension (D-PAH) is a form of World Health Organization Group 1 pulmonary hypertension (PH) characterized by severe small vessel loss and obstructive vasculopathy, which leads to progressive right heart failure and death. To date, 16 different compounds have been associated with D-PAH, including anorexinogens, recreational stimulants, and more recently, several Food and Drug Administration-approved medications. While the clinical manifestations, pathology, and hemodynamic profile of D-PAH are indistinguishable from other forms of PAH, its clinical course can be unpredictable and largely dependent on removal of the offending agent. Since only a subset of individuals develop D-PAH, it is likely that genetic susceptibility plays a role in pathogenesis, but characterization of the genetic factors responsible for disease susceptibility remains incomplete. Besides aggressive treatment with PH-specific therapies, the major challenge in the management of D-PAH remains the early identification of compounds capable of injuring the pulmonary circulation in susceptible individuals. Institution of pharmacovigilance, precision medicine strategies, and global warning systems will help facilitate identification of high-risk drugs and institute regulation strategies to prevent further outbreaks of D-PAH.

Adverse Drug Reactions in the Intensive Care Unit

Adverse drug reactions (ADRs) are undesirable effects of medications used in normal doses [1]. ADRs can occur during treatment in an intensive care unit (ICU) or result in ICU admissions. A meta-analysis of 4139 studies suggests the incidence of ADRs among hospitalized patients is 17% [2]. Because of underreporting and misdiagnosis, the incidence of ADRs may be much higher and has been reported to be as high as 36% [3]. Critically ill patients are at especially high risk because of medical complexity, numerous high-alert medications, complex and often challenging drug dosing and medication regimens, and opportunity for error related to the distractions of the ICU environment [4]. Table 1 summarizes the ADRs included in this chapter.

Low-dose fenfluramine significantly reduces seizure frequency in Dravet syndrome: a prospective study of a new cohort of patients

Background and purpose

Dravet syndrome (DS) is a severe, drug‐resistant epilepsy. Fenfluramine has been reported to have a long‐term clinically meaningful anticonvulsive effect in patients with DS.

Methods

This prospective, open‐label study assessed the safety and effectiveness of low‐dose fenfluramine in a new cohort of patients with DS. Following a 3‐month baseline period, fenfluramine was added to each patient's current antiepileptic drug regimen at a dose of 0.25–1.0 mg/kg/day (max. 20 mg/day). The incidence of major motor seizures (tonic, clonic, tonic–clonic, atonic and myoclonic seizures lasting >30 s) in both the baseline and treatment periods was assessed via a seizure diary. Periodic echocardiographic examinations during the treatment period were used to assess cardiovascular safety.

Results

Nine patients (aged 1.2–29.8 years) enrolled in the study and were treated with fenfluramine for a median duration of 1.5 (range, 0.3–5.1) years. Median frequency of major motor seizures was 15.0/month in the baseline period. All patients demonstrated a reduction in seizure frequency during the treatment period with a median reduction of 75% (range, 28–100%). Seven patients (78%) experienced a ≥50% reduction in major motor seizure frequency. The most common adverse events were somnolence (n = 5) and anorexia (n = 4). No evidence of cardiac valvulopathy or pulmonary hypertension was observed.

Conclusions

The effectiveness and safety of low‐dose fenfluramine as an add‐on therapy for DS in this new prospective cohort supports previous findings.

Can we win the war on obesity with pharmacotherapy?

INTRODUCTION

Obesity is a major health concern for several countries. The United States (U.S.) has arguably led the world in the percentage of overweight and/or obese per capita for several decades. As a result, numerous FDA-approved pharmacotherapeutic options are available for the long-term treatment of obesity. Although most of these medications have been on the U.S. market for a few years and have demonstrated efficacy for long-term weight loss in clinical trials, the impact of these medications on obesity in the U.S. has yet to be realized. Areas covered: We will review and evaluate why pharmacotherapy for obesity has not produced a meaningful reduction in the number of overweight and obese adults in the U.S. Expert commentary: Several obstacles, such as adverse drug effects, poor insurance coverage, not treating obesity as a chronic disease, and availability of other weight loss alternatives, has resulted in poor performance of pharmacotherapy for obesity in the U.S. market.

Paradoxical Effect of Prostacyclin Infusion in a Patient with Primary Pulmonary Hypertension

Prostacyclin treatment successfully delays the need for lung transplantation in many patients with progressive primary pulmonary hypertension by vasodilating pulmonary arteries. However, the treatment of pulmonary hypertension with prostacyclin may cause a paradoxical increase in pulmonary artery pressure, as shown in this case.

Clinical Presentation, Differential Diagnosis, and Vasodilator Testing of Pulmonary Hypertension

Clinicians should be cognizant of the symptoms and risk factors associated with pulmonary hypertension (PH). While known PH poses significant therapeutic challenges, occult PH carries the added potential for unanticipated complications when treating concurrent medical illnesses. PH may occur with underlying medical conditions and risk factors or may occur de novo as idiopathic pulmonary arterial hypertension (IPAH). Symptoms of PH are frequently attributed to more common conditions, and their nonspecific nature and insidious onset may lead to delay in presentation, evaluation, and diagnosis. Initial symptoms are dyspnea, fatigue, chest pain, and palpitations. Lower extremity edema, presyncope, and syncope are symptoms of more advanced disease. Thorough evaluation of symptoms and identification of patients with risk factors for PH are critical in making a timely diagnosis. History and physical examination can identify patients with suspected PH. Further testing is necessary for definitive diagnosis, classification, assessment of severity, and guiding therapeutic decisions.

Lisdexamfetamine in the treatment of moderate-to-severe binge eating disorder in adults: systematic review and exploratory meta-analysis of publicly available placebo-controlled, randomized clinical trials

BACKGROUND

Preliminary placebo-controlled evidence paved the ground to the US Food and Drug Administration approval extension of lisdexamfetamine for the treatment of moderate-to-severe binge eating disorder (BED) in adults.

OBJECTIVES

To provide a preliminary qualitative and quantitative synthesis of the placebo-controlled, randomized clinical trials (RCTs) considering the efficacy and tolerability of lisdexamfetamine in the acute and/or maintenance treatment of moderate-to-severe BED in adults.

METHODS

A preliminary, yet comprehensive, systematic review was performed by accessing a broad range of resources providing publicly available data about lisdexamfetamine at the time of inquiry (March 2016). Study eligibility criteria, participants, and interventions were considered focusing on major clinical and functional outcomes of either efficacy or tolerability of lisdexamfetamine in the treatment of moderate-to-severe BED in adults.

RESULTS

Meta-analysis of data pooled from three acute RCTs significantly favored lisdexamfetamine over placebo in the reduction of binge eating days/week, Yale-Brown Obsessive Compulsive Scale Modified for Binge Eating total score, weight, response, and remission rates (all, P≤0.01). In contrast, discontinuation rates due to treatment-emergent adverse events were significantly higher among patients in receipt of lisdexamfetamine (relative risk 2.19, P=0.04) versus placebo.

LIMITATIONS

Publication, selection, performance, attrition, reporting, sponsorship, and "diagnostic shift" biases. Lack of inclusion of adverse event effects other than those requiring discontinuation of the trial(s), as well as lack of information about clinically relevant psychiatric or other medical comorbidities, limits the overall generalizability of pooled results.

CONCLUSION

Across the included acute phase RCTs, lisdexamfetamine (at 30, 50, or 70 mg/day) led to significant reduction in a number of clinically relevant outcomes compared to placebo. Moreover, safety concerns related to adverse events, high discontinuation rates, and the need for additional long-term maintenance of RCTs solicit careful monitoring of the drug in terms of overall safety and tolerability by further RCTs.

Drugs That May Cause or Exacerbate Heart Failure: A Scientific Statement From the American Heart Association

Heart failure is a common, costly, and debilitating syndrome that is associated with a highly complex drug regimen, a large number of comorbidities, and a large and often disparate number of healthcare providers. All of these factors conspire to increase the risk of heart failure exacerbation by direct myocardial toxicity, drug-drug interactions, or both. This scientific statement is designed to serve as a comprehensive and accessible source of drugs that may cause or exacerbate heart failure to assist healthcare providers in improving the quality of care for these patients.

Five-year extended follow-up status of 10 patients with Dravet syndrome treated with fenfluramine

Dravet syndrome (DS) is a rare and therapy-resistant epilepsy syndrome. A retrospective analysis of add-on fenfluramine treatment in 12 patients with DS was published in 2012 and provided evidence of a meaningful long-term response. Herein we present the results of a subsequent 5-year prospective observation of this original cohort. Ten patients with a mean current age of 24 years were followed prospectively from 2010 until 2014. The mean current dose of fenfluramine was 0.27 mg/kg/day, with a mean treatment duration of 16.1 years. Seizure frequency was derived from a seizure diary. Cardiac examinations and assessments of clinical effectiveness and adverse events were performed at least annually. Three patients were seizure-free for the entire 5 years, and an additional four patients experienced seizure-free intervals of at least 2 years. Fenfluramine was generally well-tolerated. Two patients had mild (stable) valve thickening on the last echocardiography that was deemed clinically insignificant. No patient had any clinical or echocardiographic signs of pulmonary hypertension. These findings support the long-term control of convulsive seizures by low-dose fenfluramine while being well tolerated in this cohort of patients with DS. After up to 27 years of treatment, no patient has developed any clinical signs or symptoms of cardiac valvulopathy or pulmonary hypertension.

Review of the Ongoing Story of Appetite Suppressants, Serotonin Pathway, and Pulmonary Vascular Disease

Obesity is pandemic in the Western Hemisphere, especially in the United States (US) and is associated with morbidity and mortality. Recent data show that a large proportion of the US population is at least overweight and almost 2 in 5 Americans are obese. This ongoing trend of increasing obesity rates has led to a thriving market for anorexigens. Despite the health benefits of weight loss, several anorexigens had devastating side effects including pulmonary vascular disease which manifests as the clinical syndrome of pulmonary arterial hypertension (PAH). PAH is an incurable and fatal disease and is characterized by vascular constriction, hypertrophy, and proliferation that over time lead to right-sided cardiac failure. Over the past few decades, several weight loss medications have been associated with the development of PAH, possibly caused by an increase in systemic serotonin levels, resulting in vasoconstriction of the pulmonary arteries and initiating a cascade of pathologic vascular remodeling leading to vascular fibrosis. Once sufficient evidence for the association of these drugs with PAH or other related pathologies was found, many were removed from the market. However, there are other appetite suppressants still currently on the market (whether Food and Drug Administration-approved or "dietary supplements") that have to some extent similar mechanisms of action to those associated with PAH but lack robust enough data to prove or disprove an association. The serotonin pathway seems to be repeatedly implicated. In conclusion, given that PAH is a progressive and debilitating disease, it is important to highlight possible risk factors that could be avoided.

The serotonin transporter promotes a pathological estrogen metabolic pathway in pulmonary hypertension via cytochrome P450 1B1

Pulmonary arterial hypertension (PAH) is a devastating vasculopathy that predominates in women and has been associated with dysregulated estrogen and serotonin signaling. Overexpression of the serotonin transporter (SERT(+)) in mice results in an estrogen-dependent development of pulmonary hypertension (PH). Estrogen metabolism by cytochrome P450 1B1 (CYP1B1) contributes to the pathogenesis of PAH, and serotonin can increase CYP1B1 expression in human pulmonary arterial smooth muscle cells (hPASMCs). We hypothesized that an increase in intracellular serotonin via increased SERT expression may dysregulate estrogen metabolism via CYP1B1 to facilitate PAH. Consistent with this hypothesis, we found elevated lung CYP1B1 protein expression in female SERT(+) mice accompanied by PH, which was attenuated by the CYP1B1 inhibitor 2,3',4,5'-tetramethoxystilbene (TMS). Lungs from female SERT(+) mice demonstrated an increase in oxidative stress that was marked by the expression of 8-hydroxyguanosine; however, this was unaffected by CYP1B1 inhibition. SERT expression was increased in monocrotaline-induced PH in female rats; however, TMS did not reverse PH in monocrotaline-treated rats but prolonged survival. Stimulation of hPASMCs with the CYP1B1 metabolite 16α-hydroxyestrone increased cellular proliferation, which was attenuated by an inhibitor (MPP) of estrogen receptor alpha (ERα) and a specific ERα antibody. Thus, increased intracellular serotonin caused by increased SERT expression may contribute to PAH pathobiology by dysregulation of estrogen metabolic pathways via increased CYP1B1 activity. This promotes PASMC proliferation by the formation of pathogenic metabolites of estrogen that mediate their effects via ERα. Our studies indicate that targeting this pathway in PAH may provide a promising antiproliferative therapeutic strategy.

Pulmonary hypertension in the elderly: a different disease?

Pulmonary hypertension (PH) is a haemodynamic syndrome defined by a mean pulmonary arterial pressure (mPAP) >25 mmHg determined by right heart catheterisation (RHC) [1, 2]. A lot of ­diseases fulfil this definition, but they differ widely between each other in respect to their pathophysiology, their haemodynamic characteristics, their clinical presentation, their natural prognosis and their potential therapeutic strategies. The current guidelines on PH diagnosis and management make the distinction between five groups of more than 200 causes of PH [2], but these diseases are very different from one another. In the current classification, the first group (group 1) represents a progressive vasculopathy leading to pre-capillary PH called pulmonary arterial hypertension (PAH), characterised by a characteristic small-calibre pulmonary artery remodelling, as a result of proliferation of endothelial and smooth muscle cells as well as medial hypertrophy. So, if we compare PAH (for example idiopathic PAH) from PH due to valvular disease like mitral insufficiency (group 2.3) it is easy to understand that apart from the fact that mean pulmonary arterial pressure (mPAP) exceeds 25 mmHg in both cases, these two entities have very different pathophysiological pathways. In the first case, there is a true pulmonary vasculopathy. In the second, PH is mainly related to the consequences of an increased hydrostatic pressure in the left atrium ­transmitted to the venous compartment of the pulmonary circulation and then back through the capillary bed. If the pathophysiology of these entities is different, the targets of their treatments are too. The main goal of PAH treatment consists in reducing pulmonary vascular resistance (PVR) with specific medication and, when appropriate, with specific treatment of the underlying disease as it is the case for associated-PAH (group 1.4). Alternatively, the management of PH related to a mitral regurgitation would be to improve the ventricular preload, diminish the ventricular afterload and, if necessary, to correct the anatomical anomaly.

The distinction between PH in the elderly and normal ageing might make diagnosis difficulthttp://ow.ly/YYF1Q

Challenges and Current Efforts in the Development of Biomarkers for Chronic Inflammatory and Remodeling Conditions of the Lungs

This review discusses biomarkers that are being researched for their usefulness to phenotype chronic inflammatory lung diseases that cause remodeling of the lung's architecture. The review focuses on asthma, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension. Bio-markers of environmental exposure and specific classes of biomarkers (noncoding RNA, metabolism, vitamin, coagulation, and microbiome related) are also discussed. Examples of biomarkers that are in clinical use, biomarkers that are under development, and biomarkers that are still in the research phase are discussed. We chose to present examples of the research in biomarker development by diseases, because asthma, COPD, and pulmonary hypertension are distinct entities, although they clearly share processes of inflammation and remodeling.

Serotonin 2B Receptor Antagonism Prevents Heritable Pulmonary Arterial Hypertension

Serotonergic anorexigens are the primary pharmacologic risk factor associated with pulmonary arterial hypertension (PAH), and the resulting PAH is clinically indistinguishable from the heritable form of disease, associated with BMPR2 mutations. Both BMPR2 mutation and agonists to the serotonin receptor HTR2B have been shown to cause activation of SRC tyrosine kinase; conversely, antagonists to HTR2B inhibit SRC trafficking and downstream function. To test the hypothesis that a HTR2B antagonist can prevent BMRP2 mutation induced PAH by restricting aberrant SRC trafficking and downstream activity, we exposed BMPR2 mutant mice, which spontaneously develop PAH, to a HTR2B antagonist, SB204741, to block the SRC activation caused by BMPR2 mutation. SB204741 prevented the development of PAH in BMPR2 mutant mice, reduced recruitment of inflammatory cells to their lungs, and reduced muscularization of their blood vessels. By atomic force microscopy, we determined that BMPR2 mutant mice normally had a doubling of vessel stiffness, which was substantially normalized by HTR2B inhibition. SB204741 reduced SRC phosphorylation and downstream activity in BMPR2 mutant mice. Gene expression arrays indicate that the primary changes were in cytoskeletal and muscle contractility genes. These results were confirmed by gel contraction assays showing that HTR2B inhibition nearly normalizes the 400% increase in gel contraction normally seen in BMPR2 mutant smooth muscle cells. Heritable PAH results from increased SRC activation, cellular contraction, and vascular resistance, but antagonism of HTR2B prevents SRC phosphorylation, downstream activity, and PAH in BMPR2 mutant mice.

Low-dose fenfluramine in the treatment of neurologic disorders: experience in Dravet syndrome

In this paper, we review the experience with fenfluramine in epileptic and other paroxysmal disorders. Since the best available data are from the treatment of Dravet syndrome, we will focus primarily on this condition. Originally fenfluramine was launched as an anorectic agent. As early as 1985, seizure reduction in children could be demonstrated in a few cases with photosensitive, self-induced epilepsy. Hereafter, a small study was launched in patients with self-induced epilepsy. Results showed a significant seizure reduction, and review of the patient data showed that 5 of the 12 patients had Dravet syndrome. During that observation period, fenfluramine was withdrawn from the market because of cardiovascular side effects associated with prescribing higher doses in combination with phentermine for weight loss. In March 2002, a Belgian Royal Decree was issued permitting further study of fenfluramine in pediatric patients with intractable epilepsy. In 2011 under the Royal Decree, a prospective study of patients with Dravet syndrome treated with low-dose fenfluramine was initiated and is currently ongoing. The initial results are promising in terms of reduction of seizure frequency and overall tolerability.

Clinical features of pulmonary arterial hypertension in patients receiving dasatinib

The prognosis of most leukemia patients treated with BCR-ABL tyrosine kinase inhibitors (TKIs) is favorable, and a more precise understanding of serious and potentially irreversible treatment-related toxicities is essential to properly inform treatment choice. Few cases of pulmonary arterial hypertension (PAH) have been reported in patients with leukemia treated with dasatinib, a second-generation BCR-ABL TKI. To better understand characteristics and outcomes of dasatinib-treated patients with PAH, all clinical cases of PAH confirmed by right-heart catheterization in the Bristol-Myers Squibb pharmacovigilance database (N = 41), including 22 previously unpublished cases, were examined for previous treatments for leukemia, patient characteristics, time to PAH onset, and outcomes. Our analysis shows that compared with PAH due to other etiologies, dasatinib-related PAH is atypical, in that it is associated with partial to complete reversibility upon treatment discontinuation. The incidence of dasatinib-related PAH appears to be low. Most PAH cases were observed in patients who had received prior treatments for leukemia. No specific patient attributes appear to be associated with an increased risk of developing PAH while receiving dasatinib. Symptoms of PAH in dasatinib-treated leukemia patients should prompt a thorough workup, including consideration of confirmatory right-heart catheterization. In cases of confirmed PAH, dasatinib should be discontinued.

EET-dependent potentiation of pulmonary arterial pressure: sex-different regulation of soluble epoxide hydrolase

We tested the hypothesis that suppression of epoxyeicosatrienoic acid (EET) metabolism via genetic knockout of the gene for soluble epoxide hydrolase (sEH-KO), or female-specific downregulation of sEH expression, plays a role in the potentiation of pulmonary hypertension. We used male (M) and female (F) wild-type (WT) and sEH-KO mice; the latter have high pulmonary EETs. Right ventricular systolic pressure (RVSP) and mean arterial blood pressure (MABP) in control and in response to in vivo administration of U46619 (thromboxane analog), 14,15-EET, and 14,15-EEZE [14,15-epoxyeicosa-5(z)-enoic acid; antagonist of EETs] were recorded. Basal RVSP was comparable among all groups of mice, whereas MABP was significantly lower in F-WT than M-WT mice and further reduced predominantly in F-KO compared with M-KO mice. U46619 dose dependently increased RVSP and MABP in all groups of mice. The increase in RVSP was significantly greater and coincided with smaller increases in MABP in M-KO and F-WT mice compared with M-WT mice. In F-KO mice, the elevation of RVSP by U46619 was even higher than in M-KO and F-WT mice, associated with the least increase in MABP. 14,15-EEZE prevented the augmentation of U46619-induced elevation of RVSP in sEH-KO mice, whereas 14,15-EET-induced pulmonary vasoconstriction was comparable in all groups of mice. sEH expression in the lungs was reduced, paralleled with higher levels of EETs in F-WT compared with M-WT mice. In summary, EETs initiate pulmonary vasoconstriction but act as vasodilators systemically. High pulmonary EETs, as a function of downregulation or deletion of sEH, potentiate U46619-induced increases in RVSP in a female-susceptible manner.

Potassium channels in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating cardiopulmonary disorder with various origins. All forms of PAH share a common pulmonary arteriopathy characterised by vasoconstriction, remodelling of the pre-capillary pulmonary vessel wall, and in situ thrombosis. Although the pathogenesis of PAH is recognised as a complex and multifactorial process, there is growing evidence that potassium channels dysfunction in pulmonary artery smooth muscle cells is a hallmark of PAH. Besides regulating many physiological functions, reduced potassium channels expression and/or activity have significant effects on PAH establishment and progression. This review describes the molecular mechanisms and physiological consequences of potassium channel modulation. Special emphasis is placed on KCNA5 (Kv1.5) and KCNK3 (TASK1), which are considered to play a central role in determining pulmonary vascular tone and may represent attractive therapeutic targets in the treatment of PAH.

Characteristics of patients with pulmonary venoocclusive disease awaiting transplantation

RATIONALE

Pulmonary venoocclusive disease (PVOD) is an uncommon cause of pulmonary arterial hypertension (PAH). However, unlike PAH, treatment options for PVOD are usually quite limited. The impact of the lung allocation score on access to transplantation for patients with PVOD and the clinical course of these patients have not been well-described.

OBJECTIVES

To examine the association between the diagnosis of PVOD and lung transplantation for patients on the transplant waiting list.

METHODS

Patients with a diagnosis of PVOD and PAH registered on the United Network for Organ Sharing wait list for transplantation from May 4, 2005 to May 3, 2013 were included. Lung transplantation was the primary outcome measure. Multivariable analyses were performed to determine the odds of dying or receiving a lung transplant after listing. Survival was compared using Kaplan-Meier and competing risks methods.

RESULTS

Of 12,251 patients listed for lung transplantation, 49 with PVOD and 647 with PAH were identified. There were no significant differences in the lung allocation score between patients with PVOD and PAH at listing, transplant, or wait list removal for death/too sick for transplant. By 6 months, 22.6% of patients with PVOD had been removed from the wait list due to death, compared with 11.0% of patients with PAH (Chi-square P = 0.03). Patients with PVOD who died or were considered too sick for transplant were removed from the waiting list sooner after listing (22 vs. 105 d, P = 0.08). There was no difference in the proportion of patients with PVOD and PAH transplanted (50.0 vs. 47.6%, P = 0.60).

CONCLUSIONS

In the lung allocation score era, patients with PVOD may be at higher risk for death while on the transplant waiting list. After wait list registration, close monitoring for disease progression is advised.

Role of Pharmacovigilance in India: An overview

Pharmacovigilance (PV) plays a key role in the healthcare system through assessment, monitoring and discovery of interactions amongst drugs and their effects in human. Pharmaceutical and biotechnological medicines are designed to cure, prevent or treat diseases; however, there are also risks particularly adverse drug reactions (ADRs) can cause serious harm to patients. Thus, for safety medication ADRs monitoring required for each medicine throughout its life cycle, during development of drug such as pre-marketing including early stages of drug design, clinical trials, and post-marketing surveillance. PV is concerns with the detection, assessment, understanding and prevention of ADRs. Pharmacogenetics and pharmacogenomics are an indispensable part of the clinical research. Variation in the human genome is a cause of variable response to drugs and susceptibility to diseases are determined, which is important for early drug discovery to PV. Moreover, PV has traditionally involved in mining spontaneous reports submitted to national surveillance systems. The research focus is shifting toward the use of data generated from platforms outside the conventional framework such as electronic medical records, biomedical literature, and patient-reported data in health forums. The emerging trend in PV is to link premarketing data with human safety information observed in the post-marketing phase. The PV system team obtains valuable additional information, building up the scientific data contained in the original report and making it more informative. This necessitates an utmost requirement for effective regulations of the drug approval process and conscious pre and post approval vigilance of the undesired effects, especially in India. Adverse events reported by PV system potentially benefit to the community due to their proximity to both population and public health practitioners, in terms of language and knowledge, enables easy contact with reporters by electronically. Hence, PV helps to the patients get well and to manage optimally or ideally, avoid illness is a collective responsibility of industry, drug regulators, clinicians and other healthcare professionals to enhance their contribution to public health. This review summarized objectives and methodologies used in PV with critical overview of existing PV in India, challenges to overcome and future prospects with respect to Indian context.

Lungs at high-altitude: genomic insights into hypoxic responses

Hypobaric hypoxia at high altitude (HA) results in reduced blood arterial oxygen saturation, perfusion of organs with hypoxemic blood, and direct hypoxia of lung tissues. The pulmonary complications in the cells of the pulmonary arterioles due to hypobaric hypoxia are the basis of the pathophysiological mechanisms of high-altitude pulmonary edema (HAPE). Some populations that have dwelled at HA for thousands of years have evolutionarily adapted to this environmental stress; unadapted populations may react with excessive physiological responses that impair health. Individual variations in response to hypoxia and the mechanisms of HA adaptation provide insight into physiological responses. Adaptive and maladaptive responses include alterations in pathways such as oxygen sensing, hypoxia signaling, K+- and Ca2+-gated channels, redox balance, and the renin-angiotensin-aldosterone system. Physiological imbalances are linked with genetic susceptibilities, and nonhomeostatic responses in gene regulation that occur by small RNAs, histone modification, and DNA methylation predispose susceptible humans to these HA illnesses. Elucidation of the interaction of these factors will lead to a more comprehensive understanding of HA adaptations and maladaptations and will lead to new therapeutics for HA disorders related to hypoxic lungs.

4,4'-Methylenedianiline Alters Serotonergic Transport in a Novel, Sex-Specific Model of Pulmonary Arterial Hypertension in Rats

Pulmonary arterial hypertension (PAH) is a cardiovascular disorder characterized by elevated pulmonary artery pressure as a result of arterial wall thickening. Patients are 3-4 times more likely to be women than men. This gender discrepancy demonstrates a need for an animal model with similar sex differences. 4,4'-Methylenedianiline (DAPM) is an aromatic amine used industrially in the synthesis of polyurethanes. Chronic, intermittent treatment of male and female rats with DAPM resulted in medial hyperplasia of pulmonary arterioles, exclusively in females, coupled to increases in pulmonary arterial pressures. Significant increases in plasma levels of endothelin-1 (ET-1) and serotonin, but decreases in nitrite [Formula: see text], were observed in females treated with DAPM. A decrease was observed in the serum ratio of the estrogen metabolites 2-hydroxyestradiol (2-OHE1)/16α-hydroxyestrogen (16α-OHE1). In females, ET-1,[Formula: see text] , and 2-OHE1/16α-OHE1 were significantly correlated with peak pressure gradient, an indirect measure of pulmonary arterial pressure. Expression of the serotonin transport protein (SERT) was significantly higher in the arteries of DAPM-treated females. In vitro, DAPM induced human pulmonary vascular smooth muscle cell proliferation and serotonin uptake, both of which were inhibited by treatment with the estrogen receptor antagonist ICI 182,780 or the selective serotonin reuptake inhibitor fluoxetine. DAPM also induced the release of serotonin from human pulmonary endothelial cells in culture, which is blocked by ICI 182,780. Taken together, this suggests that DAPM-mediated dysregulation of serotonin transport is estrogen-receptor dependent. Thus, DAPM-induced PAH pathology may be a new tool to clarify the sex selectivity of PAH disease pathogenesis.

5-HT2B receptor antagonists inhibit fibrosis and protect from RV heart failure

Objective. The serotonin (5-HT) pathway was shown to play a role in pulmonary hypertension (PH), but its functions in right ventricular failure (RVF) remain poorly understood. The aim of the current study was to investigate the effects of Terguride (5-HT2A and 2B receptor antagonist) or SB204741 (5-HT2B receptor antagonist) on right heart function and structure upon pulmonary artery banding (PAB) in mice. Methods. Seven days after PAB, mice were treated for 14 days with Terguride (0.2 mg/kg bid) or SB204741 (5 mg/kg day). Right heart function and remodeling were assessed by right heart catheterization, magnetic resonance imaging (MRI), and histomorphometric methods. Total secreted collagen content was determined in mouse cardiac fibroblasts isolated from RV tissues. Results. Chronic treatment with Terguride or SB204741 reduced right ventricular fibrosis and showed improved heart function in mice after PAB. Moreover, 5-HT2B receptor antagonists diminished TGF-beta1 induced collagen synthesis of RV cardiac fibroblasts in vitro. Conclusion. 5-HT2B receptor antagonists reduce collagen deposition, thereby inhibiting right ventricular fibrosis. Chronic treatment prevented the development and progression of pressure overload-induced RVF in mice. Thus, 5-HT2B receptor antagonists represent a valuable novel therapeutic approach for RVF.