[Targeted therapy for pulmonary arterial hypertension in patients without comorbidities]. / Gezielte medikamentöse Therapie der pulmonalarteriellen Hypertonie bei Patient*innen ohne Komorbiditäten.

The 2022 guidelines on pulmonary hypertension from the European Society of Cardiology (ESC) and the European Respiratory Society (ERS) provide therapeutic strategies that account for the variability in the clinical presentation of newly diagnosed patients. We summarize treatment recommendations for pulmonary arterial hypertension (PAH) in patients without significant comorbidities, particularly for idiopathic, hereditary, drug/toxin-induced, or connective tissue disease-associated PAH. In this group of patients, multidimensional assessments for short-term mortality risk guide initial treatment decisions and treatment decisions during follow-up. Upfront dual combination therapy (phosphodiesterase type-5 inhibitor and endothelin receptor antagonist) is recommended for low- and intermediate-risk patients, and triple therapy including a parenteral prostacyclin should be considered in high- or intermediate-high-risk patients. If a low or intermediate-low-risk profile cannot be achieved during therapy, sequential add-on therapy escalation with parenteral prostacyclin or a prostacyclin receptor agonist should be considered, and switching from a phosphodiesterase type-5 inhibitor to a guanylate cyclase stimulator may also be considered.

Management of Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a rare pulmonary vascular disease characterized by progressive pulmonary arterial remodeling, increased pulmonary vascular resistance, right ventricular dysfunction, and reduced survival. Effective therapies have been developed that target three pathobiologic pathways in PAH: nitric oxide, endothelin-1, and prostacyclin. Approved therapies for PAH include phosphodiesterase type-5 inhibitors, soluble guanylate cyclase stimulators, endothelin receptor antagonists, prostacyclin analogs, and prostacyclin receptor agonists. Management of PAH in the modern era incorporates multidimensional risk assessment to guide the use of these medications. For patients with PAH and without significant comorbidities, current guidelines recommend two oral medications (phosphodiesterase type-5 inhibitor and endothelin receptor antagonist) for low- and intermediate-risk patients, with triple therapy including a parenteral prostacyclin to be considered in those at high or intermediate-high risk. Combination therapy may be poorly tolerated and less effective in patients with PAH and cardiopulmonary comorbidities. Thus, a single-agent approach with individualized decisions to add-on other PAH therapies is recommended in older patients and those with significant comorbid conditions. Management of PAH is best performed in multidisciplinary teams located in experienced centers. Other core pillars of PAH management include supportive and adjunctive treatments including oxygen, diuretics, rehabilitation, and anticoagulation in certain patients. Patients with PAH who progress despite optimal treatment or who are refractory to best medical care should be referred for lung transplantation, if eligible. Despite considerable progress, PAH is often fatal and new therapies that reverse the disease and improve outcomes are desperately needed.

Ensifentrine, a Novel Phosphodiesterase 3 and 4 Inhibitor for the Treatment of Chronic Obstructive Pulmonary Disease: Randomized, Double-Blind, Placebo-controlled, Multicenter Phase III Trials (the ENHANCE Trials).

Rationale: Ensifentrine is a novel, selective, dual phosphodiesterase (PDE)3 and PDE4 inhibitor with bronchodilator and antiinflammatory effects. Replicate phase III trials of nebulized ensifentrine were conducted (ENHANCE-1 and ENHANCE-2) to assess these effects in patients with chronic obstructive pulmonary disease (COPD). Objectives: To evaluate the efficacy of ensifentrine compared with placebo for lung function, symptoms, quality of life, and exacerbations in patients with COPD. Methods: These phase III, multicenter, randomized, double-blind, parallel-group, placebo-controlled trials were conducted between September 2020 and December 2022 at 250 research centers and pulmonology practices in 17 countries. Patients aged 40-80 years with moderate to severe symptomatic COPD were enrolled. Measurements and Main Results: Totals of 760 (ENHANCE-1) and 789 (ENHANCE-2) patients were randomized and treated, with 69% and 55% receiving concomitant long-acting muscarinic antagonists or long-acting ß2-agonists, respectively. Post-bronchodilator FEV1 percentage predicted values were 52% and 51% of predicted normal. Ensifentrine treatment significantly improved average FEV1 area under the curve at 0-12 hours versus placebo (ENHANCE-1, 87 ml [95% confidence interval, 55, 119]; ENHANCE-2, 94 ml [65, 124]; both P < 0.001). Ensifentrine treatment significantly improved symptoms (Evaluating Respiratory Symptoms) and quality of life (St. George's Respiratory Questionnaire) versus placebo at Week 24 in ENHANCE-1 but not in ENHANCE-2. Ensifentrine treatment reduced the rate of moderate or severe exacerbations versus placebo over 24 weeks (ENHANCE-1, rate ratio, 0.64 [0.40, 1.00]; P = 0.050; ENHANCE-2, rate ratio, 0.57 [0.38, 0.87]; P = 0.009) and increased time to first exacerbation (ENHANCE-1, hazard ratio, 0.62 [0.39, 0.97]; P = 0.038; ENHANCE-2, hazard ratio, 0.58 [0.38, 0.87]; P = 0.009). Adverse event rates were similar to those for placebo. Conclusions: Ensifentrine significantly improved lung function in both trials, with results supporting exacerbation rate and risk reduction in a broad COPD population and in addition to other classes of maintenance therapies. Clinical trial registered with www. CLINICALTRIALS: gov and EudraCT (ENHANCE-1, www. CLINICALTRIALS: gov identifier NCT04535986, EudraCT identifier 2020-002086-34; ENHANCE-2, www. CLINICALTRIALS: gov identifier NCT04542057, EudraCT identifier 2020-002069-32).

Effect of vinpocetine alone and in combination with enalapril in experimental model of diabetic cardiomyopathy in rats: possible involvement of PDE-1/TGF-ß/ Smad 2/3 signalling pathways.

OBJECTIVE: Diabetic cardiomyopathy (DC) is one of the severe secondary complications of diabetes mellitus in humans. Vinpocetine is an alkaloid having pleiotropic pharmacological effects. The present study is designed to investigate the effect of vinpocetine in DC in rats. METHODS: Rats were fed a high-fat diet for nine weeks along with single dose of streptozotocin after the second week to induce DC. The haemodynamic evaluation was performed to assess the functional status of rats using the Biopac system. Cardiac echocardiography, biochemical, oxidative stress parameters and inflammatory cytokine level were analysed in addition to haematoxylin-eosin and Masson's trichome staining to study histological changes, cardiomyocyte diameter and fibrosis, respectively. Phosphodiesterase-1 (PDE-1), transforming growth factor-ß (TGF-ß) and p-Smad 2/3 expression in cardiac tissues were quantified using western blot/RT-PCR. KEY FINDING: Vinpocetine treatment and its combination with enalapril decreased the glucose levels compared to diabetic rats. Vinpocetine improved the echocardiographic parameters and cardiac functional status of rats. Vinpocetine decreased the cardiac biochemical parameters, oxidative stress, inflammatory cytokine levels, cardiomyocyte diameter and fibrosis in rats. Interestingly, expressions of PDE-1, TGF-ß and p-Smad 2/3 were ameliorated by vinpocetine alone and in combination with enalapril. CONCLUSIONS: Vinpocetine is a well-known inhibitor of PDE-1 and the protective effect of vinpocetine in DC is exerted by inhibition of PDE-1 and subsequent inhibition of the expression of TGF-ß/Smad 2/3.

Augmentation of Natriuretic Peptide Bioactivity via Combined Inhibition of Neprilysin and Phosphodiesterase-9 in Heart Failure.

BACKGROUND: The natriuretic peptides (NPs) are potent natriuretic/diuretic and vasodilatory factors, and augmentation of their levels or signaling via inhibition of the enzymes neprilysin (NEP) and phosphodiesterase 9 (PDE9), respectively, has beneficial actions in heart failure (HF). OBJECTIVES: The authors investigated dual enhancement of NP bioactivity by combining PDE9 inhibition and NEP inhibition in HF using an ovine model. METHODS: Eight sheep with pacing-induced HF received on 4 separate days intravenous PDE9 inhibition (PF-04749982), NEP inhibition (SCH-32615), PDE9 inhibition + NEP inhibition (PI+NI), and vehicle control treatment. RESULTS: Compared with the control treatment, NEP inhibition significantly increased plasma NP concentrations with a corresponding rise in second messenger cyclic guanosine monophosphate (cGMP), whereas PDE9 inhibition increased circulating cGMP with a negligible effect on NP levels. Combined PI+NI elevated plasma NPs to an extent comparable to that seen with NEP inhibition alone but further increased cGMP, resulting in a rise in the cGMP-to-NP ratio. All active treatments reduced mean arterial pressure, left atrial pressure, pulmonary arterial pressure, and peripheral resistance, with combined PI+NI further reducing mean arterial pressure and left atrial pressure relative to either inhibitor separately. Active treatments increased urine volume and sodium, potassium and creatinine excretion, and creatinine clearance, in association with rises in urine cGMP levels. PI+NI induced a significantly greater natriuresis and increase in urinary cGMP relative to either inhibitor singly. CONCLUSIONS: The present study demonstrates for the first time that combined PI+NI has additional beneficial hemodynamic and renal effects when compared with either PDE9 inhibition or NEP inhibition alone. The superior efficacy of this 2-pronged augmentation of NP bioactivity supports PI+NI as a potential therapeutic strategy for HF.

Association Between Prosthetic Knee Effusions and Phosphodiesterase Type-5 Enzyme Inhibitor Use After Total Knee Arthroplasty: A Case Report.

CASE: Phosphodiesterase type-5 enzyme (PDE5) inhibitors are well tolerated and used to treat erectile dysfunction. We report a case of prosthetic knee effusions associated with PDE5 inhibitor use in a 65-year-old man after total knee arthroplasty (TKA). PDE5 inhibitor treatment was stopped, and the patient had no further episodes of painful effusions. CONCLUSION: This report describes a previously unknown adverse effect of PDE5 inhibitor use in a prosthetic joint after TKA. We hope to encourage physicians managing patients after joint replacement to be aware of the association between PDE5 inhibitor use and recurrent joint effusions to improve postoperative outcomes.

Update on Oxytocin, Phosphodiesterase, Neurokinin, Glycine as a Therapeutic Approach in the Treatment of Schizophrenia.

BACKGROUND: Schizophrenia is a chronic psychiatric disorder characterized by disrupted thoughts, perception, mood, and behavior. It has a heterogeneous genetic and neurobiological background and affects about 0.5-1% of the adult population worldwide. Herein, we review the current approaches and advances in schizophrenia. The potential therapeutic compounds for the treatment of schizophrenia act on the oxytocin receptor, phosphodiesterase system, neurokinin receptor, and glycine transport 1 receptor. Therefore, this article provides an update on the pharmacology of different receptors in addition to the dopaminergic system. These findings would guide the readers on novel targets for schizophrenia with the potential to be therapeutic agents in the future. OBJECTIVE: To provide the researchers an update on the emerging role of oxytocin, phosphodiesterase, neurokinin, and glycine which can be explored as potential pharmacotherapeutic targets in the treatment of schizophrenia. METHODS: An extensive literature search was conducted using PubMed, Science Direct, and NCBI with the following keywords: schizophrenia, novel receptors, oxytocin, phosphodiesterase, neurokinin, and glycine. Furthermore, to provide insights into newer drug treatments for Schizophrenia, Furthermore, Clinicaltrials.gov website was searched for newer receptor-based drugs. RESULTS: Current literature supported by preclinical and clinical provides substantial evidence that oxytocin, phosphodiesterase, neurokinin, and glycine play a crucial role in Schizophrenia. CONCLUSION: Our findings indicate that though multiple antipsychotic drugs are prescribed to treat schizophrenia, novel approaches and/or mechanisms are plausible. Moreover, sensitive and specific diagnostic tools and safe and effective interventions, including novel therapeutic agents, are required to yield substantially improved future outcomes.

An insight into reactivity and bioactivity properties of quorum sensing peptides against PDE10A: a computational peptidology approach.

Peptides are currently the most promising lead molecules. Quorum sensing peptides have a variety of structural features and are regularly exposed to post-translational modifications. Antiparkinsonian drugs lose their efficacy after a long period of use, and patients develop motor problems such as drug-induced dyskinesia (DIDs). The interaction between PDE10A and cAMP is necessary for dopamine neurotransmission and may play a role in Parkinson's disease pathogenesis. cAMP and cGMP are cyclic nucleotides that act as secondary messengers in the signal transduction pathway, influencing a range of CNS activities. PDE enzymes hydrolyze phosphodiester bonds to break down cAMP and cGMP, allowing them to control intracellular levels of these second messengers effectively. PDE expression, and hence cyclic nucleotide levels and their downstream targets, may change with age and in numerous age-related illnesses, including Parkinson's disease, according to mounting evidence. At the peak of dyskinesias, cyclic nucleotide levels were lower, and using phosphodiesterase inhibitors before antiparkinsonian medicines reduced the severity of dyskinesias. In a recent study, PapRIV was found to have the ability to activate BV-2 microglia cells, indicating that this quorum sensing peptide may play a role in gut-brain contact. As a result of the current in silico work, mainly focused on QSPs as a lead molecule for inhibiting PDE10A, the SRNAT QSP sequence has been a potent molecule in molecular docking and molecular dynamics simulations. Furthermore, we can test the efficiency of therapeutic components in vitro and in vivo utilizing this computational approach against PDE10A.

A double-blind, randomized, placebo-controlled proof of concept study of the efficacy and safety of Lu AF11167 for persistent negative symptoms in people with schizophrenia.

Lu AF11167 is a selective, high-affinity inhibitor of PDE10A that modulates dopamine D1 and D2 receptor-mediated intraneuronal signalling without binding to these receptors. This randomized, double-blind, parallel-group, placebo-controlled study (NCT03793712) with open-label extension (NCT03929497) evaluated the efficacy of two fixed-flexible doses (1-2mg/day and 3-4mg/day) of Lu AF11167 in stable, non-acute patients with schizophrenia and persistent prominent negative symptoms. The studies were discontinued following a futility analysis of the double-blind study, and we report data collected up to study termination. Of the 210 patients screened, 162 were randomized, 111 completed the double-blind study and 96 entered the open-label study before early termination. The withdrawal rate due to impending relapse was low and comparable across treatment groups (n = 2-4 per group in the double-blind study and n = 1 in the open-label extension). Double-blind treatment with Lu AF11167 3-4mg was not superior to placebo in the reduction of Brief Negative Symptom Scale (BNSS) total scores from Baseline to Week 12 (primary endpoint); adjusted mean changes were -6.8 with placebo, -5.7 with Lu AF11167 1-2 mg group and -6.0 with Lu AF11167 3-4mg. Treatment with Lu AF11167 1-2mg also failed to separate from placebo on the primary endpoint. Neither dose group showed significant improvements versus placebo on any of the secondary efficacy measures exploring effect of treatment on overall symptomology, negative symptoms, positive symptoms, or functioning. Administration of Lu AF11167 was safe and well tolerated and adverse events were not a major reason for withdrawal from the study.

The clinical relevance of Raynaud's phenomenon symptom characteristics in systemic sclerosis.

Raynaud's phenomenon (RP) is a cardinal feature of systemic sclerosis (SSc) and manifests with pain, digital colour change, sensory symptoms, and impaired function. SSc-RP is exacerbated by cold exposure (RP 'attacks') but many patients report persistent symptoms of background digital ischaemia. The aim of our study was to examine the significance of RP with digital colour change with or without symptoms, and persistent colour change in between attacks. Patients with SSc responses were obtained from the Patient Survey of experiences of Raynaud's Phenomenon (PASRAP). We enquired about symptoms associated with Raynaud's attacks, and persistent symptoms in between attacks. Data were analysed as descriptive statistics with appropriate parametric/non-parametric testing. Relevant PASRAP survey question data from 747 evaluable SSc patients from across three continents were analysed. Isolated colour change was rare (29/484, 6%). Digital ulcers were more common in SSc-RP associated with other sensory symptoms (42.1% vs. 24.1%, P=0.057) and more readily treated with phosphodiesterase-type 5 inhibitors (22.5% vs. 10.3%%, P=0.124). Over one-third of patients (n=92/239, 38%) reported persistent colour change in between Raynaud's attacks. Patients with persistent colour change were more likely to have pulmonary arterial hypertension (15.2% vs. 7.5%, P=0.057) and be treated with calcium channel blockers (54.3% vs. 39.0%, P=0.021). SSc-RP with colour change and other symptoms and/or or persistent decolourisation in between attacks were more likely to have vascular complications of SSc and be treated with vascular therapies. Future research should explore the judicious use of vascular therapies as a potential form of disease modification in SSc. Key Points • Isolated colour change without other symptoms is rare in SSc patients. • SSc patients often identify persistent symptoms in between attacks of RP. • SSc-RP with colour change and other symptoms, or persistent decolourisation, may have greater disease severity and be treated with vascular therapies.

INZ-701, a recombinant ENPP1 enzyme, prevents ectopic calcification in an Abcc6-/- mouse model of pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE), a heritable multisystem ectopic calcification disorder, is predominantly caused by inactivating mutations in ABCC6. The encoded protein, ABCC6, is a hepatic efflux transporter and a key regulator of extracellular inorganic pyrophosphate (PPi). Recent studies demonstrated that deficiency of plasma PPi, a potent endogenous calcification inhibitor, is the underlying cause of PXE. This study examined whether restoring plasma PPi levels by INZ-701, a recombinant human ENPP1 protein, the principal PPi-generating enzyme, prevents ectopic calcification in an Abcc6-/- mouse model of PXE. Abcc6-/- mice, at 6 weeks of age, the time of earliest stages of ectopic calcification, were injected subcutaneously with INZ-701 at 2 or 10 mg/kg for 2 or 8 weeks. INZ-701 at both doses increased steady-state plasma ENPP1 activity and PPi levels. In the 8-week treatment study, histopathologic examination and quantification of the calcium content in INZ-701-treated Abcc6-/- mice revealed significantly reduced calcification in the muzzle skin containing vibrissae, a biomarker of the calcification process in these mice. The extent of calcification corresponds to the local expression of two calcification inhibitors, osteopontin and fetuin-A. These results suggest that INZ-701 might provide a therapeutic approach for PXE, a disease with high unmet needs and no approved treatment.

Longitudinal assessment of vascular calcification in generalized arterial calcification of infancy.

BACKGROUND: Generalized arterial calcification of infancy (GACI), also known as idiopathic infantile arterial calcification, is a very uncommon genetic disorder characterized by calcifications and stenoses of large- and medium-size arteries that can lead to end-organ damage. OBJECTIVE: To describe changes in imaging findings in 10 children with GACI at a single institution from 2010 to 2021. MATERIALS AND METHODS: In this retrospective study we reviewed initial and follow-up body imaging in children with genetic confirmation of GACI at our hospital. All initial images were analyzed for the presence and distribution of arterial calcifications, stenoses and wall thickening/irregularity within the chest, abdomen and pelvis. We compared available follow-up studies to the initial imaging findings. We extracted clinical information including prenatal and postnatal treatment from the children's medical records. RESULTS: We evaluated 10 children (five boys) with a diagnosis of GACI. Median age at first body imaging was 8 days (range: 1 day to 5 years). Six children were identified prenatally and four postnatally. Postnatal presentation included cardiac failure, seizures and hypertension. Images in newborns (n = 8) most commonly showed diffuse arterial calcifications (6/8; 75%), while stenoses were less common (2/8; 25%) during this period. Two children were diagnosed after the neonatal period - one in infancy and one during childhood. In total, half the children (5/10; 50%) had arterial stenoses - three cases visualized at first imaging and two identified on follow-up images during infancy. Stenoses had completely resolved in one child (1/5; 20%) at last follow-up. Eight children received prenatal or postnatal treatment or both. All children who received both prenatal and postnatal treatment (n = 4) had completely resolved calcifications at last follow-up. CONCLUSION: Children with GACI might have characteristic vascular calcifications at birth that raise the suspicion of this disease. Arterial calcifications decrease or disappear spontaneously or after treatment, but arterial stenoses usually persist. Calcifications and arterial stenoses can be easily identified and followed with non-contrast CT and CT angiography.

Compounds enhancing human sperm motility identified using a high-throughput phenotypic screening platform.

STUDY QUESTION: Can a high-throughput screening (HTS) platform facilitate male fertility drug discovery? SUMMARY ANSWER: An HTS platform identified a large number of compounds that enhanced sperm motility. WHAT IS KNOWN ALREADY: Several efforts to find small molecules modulating sperm function have been performed but none have used high-throughput technology. STUDY DESIGN, SIZE, DURATION: Healthy donor semen samples were used and samples were pooled (3-5 donors per pool). Primary screening was performed singly; dose-response screening was performed in duplicate (using independent donor pools). PARTICIPANTS/MATERIALS, SETTING, METHODS: Spermatozoa isolated from healthy donors were prepared by density gradient centrifugation and incubated in 384-well plates with compounds (6.25 µM) to identify those compounds with enhancing effects on motility. Approximately 17 000 compounds from the libraries, ReFRAME, Prestwick, Tocris, LOPAC, CLOUD and MMV Pathogen Box, were screened. Dose-response experiments of screening hits were performed to confirm the enhancing effect on sperm motility. Experiments were performed in a university setting. MAIN RESULTS AND THE ROLE OF CHANCE: From our primary single concentration screening, 105 compounds elicited an enhancing effect on sperm motility compared to dimethylsulphoxide-treated wells. Confirmed enhancing compounds were grouped based on their annotated targets/target classes. A major target class, phosphodiesterase inhibitors, were identified, in particular PDE10A inhibitors as well as number of compounds not previously known to enhance human sperm motility, such as those related to GABA signalling. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Although this approach provides data about the activity of the compound, it is only a starting point. For example, further substantive experiments are necessary to provide a more comprehensive picture of each compound's activity, the effect on the kinetics of the cell populations and subpopulations, and their potential mechanisms of action. Compounds have been tested with prepared donor spermatozoa, incubated under non-capacitating conditions, and only incubated with compounds for a relatively short period of time. Therefore, the effect of compounds under different conditions, for example in whole semen, for longer incubation times, or using samples from patient groups, may be different and require further study. All experiments were performed in vitro. WIDER IMPLICATIONS OF THE FINDINGS: This phenotypic screening assay identified a large number of compounds that increased sperm motility. In addition to furthering our understanding of human sperm function, for example identifying new avenues for discovery, we highlight potential compounds as promising start-point for a medicinal chemistry programme for potential enhancement of male fertility. Moreover, with disclosure of the results of screening, we present a substantial resource to inform further work in the field. STUDY FUNDING/COMPETING INTEREST(S): This study was supported by the Bill and Melinda Gates Foundation, Scottish Funding Council and Scottish Universities Life Science Alliance. C.L.R.B. is Editor for RBMO. C.L.R.B. receives funding from Chief Scientists Office (Scotland), ESHRE and Genus PLC, consulting fees from Exscientia and lecture fees from Cooper Surgical and Ferring. S.M.d.S. is an Associate Editor of Human Reproduction, and an Associate Editor of Reproduction and Fertility. S.M.d.S. receives funding from Cooper Surgical and British Dietetic Society. No other authors declared a COI.

Oral supplementation of inorganic pyrophosphate in pseudoxanthoma elasticum.

Pseudoxanthoma elasticum (PXE; OMIM 264800) is a rare heritable multisystem disorder, characterized by ectopic mineralization affecting elastic fibres in the skin, eyes and the cardiovascular system. Skin findings often lead to early diagnosis of PXE, but currently, no specific treatment exists to counteract the progression of symptoms. PXE belongs to a group of Mendelian calcification disorders linked to pyrophosphate metabolism, which also includes generalized arterial calcification of infancy (GACI) and arterial calcification due to CD73 deficiency (ACDC). Inactivating mutations in ABCC6, ENPP1 and NT5E are the genetic cause of these diseases, respectively, and all of them result in reduced inorganic pyrophosphate (PPi ) concentration in the circulation. Although PPi is a strong inhibitor of ectopic calcification, oral supplementation therapy was initially not considered because of its low bioavailability. Our earlier work however demonstrated that orally administered pyrophosphate inhibits ectopic calcification in the animal models of PXE and GACI, and that orally given Na4 P2 O7 is absorbed in humans. Here, we report that gelatin-encapsulated Na2 H2 P2 O7  has similar absorption properties in healthy volunteers and people affected by PXE. The sodium-free K2 H2 P2 O7 form resulted in similar uptake in healthy volunteers and inhibited calcification in Abcc6-/- mice as effectively as its sodium counterpart. Novel pyrophosphate compounds showing higher bioavailability in mice were also identified. Our results provide an important step towards testing oral PPi in clinical trials in PXE, or potentially any condition accompanied by ectopic calcification including diabetes, chronic kidney disease or ageing.

Inhaled Dual Phosphodiesterase 3/4 Inhibitors for the Treatment of Patients with COPD: A Short Review.

Current pharmacological treatments for chronic obstructive pulmonary disease (COPD) are mostly limited to inhaled bronchodilators and corticosteroids. Azithromycin can contribute to exacerbation prevention. Roflumilast, a phosphodiesterase (PDE) 4 inhibitor administered orally, also prevents exacerbations in selected patients with chronic bronchitis, recurrent exacerbations, severe airflow limitation and concomitant therapy with long-acting inhaled bronchodilators. This outcome likely results from anti-inflammatory effects since PDE4 is expressed by all inflammatory cell types involved in COPD. The use of this agent is, however, limited by side-effects, particularly nausea and diarrhea. To address remaining unmet needs and enrich therapeutic options for patients with COPD, inhaled dual PDE3/4 inhibitors have been developed, with the aim of enhancing bronchodilation through PDE3 inhibition and modulating inflammation and mucus production though PDE4 inhibition, thus producing a potentially synergistic effect on airway calibre. Experimental preclinical data confirmed these effects in vitro and in animal models. At present, RPL554/ensifentrine is the only agent of this family in clinical development. It decreases sputum markers of both neutrophilic and eosinophilic inflammation in patients with COPD. Clinical Phase II trials confirmed its bronchodilator effect and demonstrated clinically meaningful symptom relief and quality of life improvements in these patients. The safety profile appears satisfactory, with less effects on heart rate and blood pressure than salbutamol and no other side effect. Altogether, these data suggest that ensifentrine could have a role in COPD management, especially in addition to inhaled long-acting bronchodilators with or without corticosteroids since experimental studies suggest potentiation of ensifentrine effects by these agents. However, results from ongoing and future Phase III studies are needed to confirm both beneficial effects and favourable safety profile on a larger scale and assess other outcomes including exacerbations, lung function decline, comorbidities and mortality.

A Dose-Ranging Study of the Novel Inhaled Dual PDE 3 and 4 Inhibitor Ensifentrine in Patients with COPD Receiving Maintenance Tiotropium Therapy.

PURPOSE: Ensifentrine is an inhaled dual inhibitor of phosphodiesterase (PDE) 3 and 4 that has shown bronchodilatory effects and symptom improvement in clinical studies in patients with chronic obstructive pulmonary disease (COPD), and anti-inflammatory effects in healthy volunteers in a model of COPD-like inflammation. This manuscript reports on the results of the clinical study examining if ensifentrine provides meaningful improvements in lung function when added on to tiotropium over 4 weeks in patients with COPD who have impaired lung function and symptoms despite treatment with tiotropium. PATIENTS AND METHODS: This randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study recruited patients with moderate-to-severe COPD. Patients were randomized to open-label tiotropium once daily (QD) plus (+) blinded escalating doses of ensifentrine or placebo twice daily (BID). Effects on lung function, symptoms and quality of life (QoL) were assessed over 4 weeks. RESULTS: A total of 416 COPD patients were randomized and 413 received at least one dose of blinded study medication + tiotropium. All ensifentrine doses produced a significant and dose-dependent increase in peak forced expiratory volume in 1 second (FEV1) from baseline to Week 4, with placebo-corrected differences of 77.5 mL when added to tiotropium (0.375 mg; 95% CI: 4.8, 150.1 mL; p=0.037) to 124.2 mL (3 mg; 95% CI: 51.0, 196.8 mL; p<0.001). A significant increase in average FEV1 (0-12h) was shown at Week 4 with the 3 mg dose (87.3 mL; 95% CI: 20.0, 154.5 mL; p=0.011). Clinically meaningful and statistically significant improvements in the St. George's Respiratory Questionnaire - COPD (SGRQ-C) additive to tiotropium were observed at Week 4, exceeding the minimally clinically important difference of 4 units with the 1.5 and 3 mg doses. Adverse events were similar in frequency between the ensifentrine and placebo arms. CONCLUSION: This clinical study demonstrated that nebulized ensifentrine added on to tiotropium produced clinically important improvements in lung function and QoL over 4 weeks in COPD patients receiving tiotropium who demonstrated symptoms and lung function impairment, with a safety profile similar to placebo.

Role of lysophosphatidic acid and its receptors in health and disease: novel therapeutic strategies.

Lysophosphatidic acid (LPA) is an abundant bioactive phospholipid, with multiple functions both in development and in pathological conditions. Here, we review the literature about the differential signaling of LPA through its specific receptors, which makes this lipid a versatile signaling molecule. This differential signaling is important for understanding how this molecule can have such diverse effects during central nervous system development and angiogenesis; and also, how it can act as a powerful mediator of pathological conditions, such as neuropathic pain, neurodegenerative diseases, and cancer progression. Ultimately, we review the preclinical and clinical uses of Autotaxin, LPA, and its receptors as therapeutic targets, approaching the most recent data of promising molecules modulating both LPA production and signaling. This review aims to summarize the most update knowledge about the mechanisms of LPA production and signaling in order to understand its biological functions in the central nervous system both in health and disease.

Improving the Pharmacodynamics and In Vivo Activity of ENPP1-Fc Through Protein and Glycosylation Engineering.

Enzyme replacement with ectonucleotide pyrophosphatase phospodiesterase-1 (ENPP1) eliminates mortality in a murine model of the lethal calcification disorder generalized arterial calcification of infancy. We used protein engineering, glycan optimization, and a novel biomanufacturing platform to enhance potency by using a three-prong strategy. First, we added new N-glycans to ENPP1; second, we optimized pH-dependent cellular recycling by protein engineering of the Fc neonatal receptor; finally, we used a two-step process to improve sialylation by first producing ENPP1-Fc in cells stably transfected with human α-2,6-sialyltransferase (ST6) and further enhanced terminal sialylation by supplementing production with 1,3,4-O-Bu3 ManNAc. These steps sequentially increased the half-life of the parent compound in rodents from 37 hours to ~ 67 hours with an added N-glycan, to ~ 96 hours with optimized pH-dependent Fc recycling, to ~ 204 hours when the therapeutic was produced in ST6-overexpressing cells with 1,3,4-O-Bu3 ManNAc supplementation. The alterations were demonstrated to increase drug potency by maintaining efficacious levels of plasma phosphoanhydride pyrophosphate in ENPP1-deficient mice when the optimized biologic was administered at a 10-fold lower mass dose less frequently than the parent compound-once every 10 days vs. 3 times a week. We believe these improvements represent a general strategy to rationally optimize protein therapeutics.

Symptom Improvement Following Treatment with the Inhaled Dual Phosphodiesterase 3 and 4 Inhibitor Ensifentrine in Patients with Moderate to Severe COPD - A Detailed Analysis.

Introduction: Ensifentrine is an inhaled first-in-class dual inhibitor of phosphodiesterase (PDE) 3 and 4. In a four-week randomized, double-blind, placebo-controlled, parallel-group study in patients with chronic obstructive pulmonary disease (COPD), nebulized ensifentrine 0.75 to 6mg twice daily significantly improved bronchodilation and symptoms, with all doses being well tolerated. Here, we report data for a number of prespecified exploratory and post hoc endpoints from this study that help to further profile the effect of ensifentrine on symptoms. Methods: Eligible patients were males or females aged 40-75 years with COPD, post-bronchodilator forced expiratory volume in 1 second 40-80% predicted. Other than being clinically stable for at least four weeks prior to entry, there were no symptomatic inclusion or exclusion criteria. The outcome measures reported in this manuscript are the Evaluating Respiratory Symptoms [E-RS™:COPD] questionnaire total score and subscales (breathlessness, cough/sputum and chest symptoms) at Weeks 1-4, Transition Dyspnea Index (TDI) focal score at Weeks 2 and 4, and St George's Respiratory Questionnaire - COPD Specific (SGRQ-C) total score and domain data (symptoms, activity and impacts) at Week 4. Results: There was a gradual improvement versus placebo with all ensifentrine doses for all three E-RS™:COPD subscales from Week 1 to Week 4, with the greatest ensifentrine effect on the breathlessness subscale, and all four doses superior to placebo from Week 2 onwards (p<0.05). For TDI focal score, all ensifentrine doses were superior to placebo at Weeks 2 and 4 (p<0.05). In the individual SGRQ-C domains at Week 4, ensifentrine had the greatest effect on the symptoms domain, with ensifentrine 6mg superior to placebo (p<0.05). Conclusion: In these analyses, ensifentrine demonstrated a notable early and meaningful effect on dyspnea, with this effect observed across two different assessment tools.

Autotaxin inhibition attenuates endothelial permeability after ischemia-reperfusion injury.

BACKGROUND: Autotaxin (ATX-secretory lysophospholipase D) is the primary lysophosphatidic acid (LPA) producing enzyme. LPA promotes endothelial hyper-permeability and microvascular dysfunction following cellular stress. OBJECTIVE: We sought to assess whether ATX inhibition would attenuate endothelial monolayer permeability after anoxia-reoxygenation (A-R) in vitro and attenuate the increase in hydraulic permeability observed after ischemia-reperfusion injury (IRI) in vivo. METHODS: A permeability assay assessed bovine endothelial monolayer permeability during anoxia-reoxygenation with/without administration of pipedimic acid, a specific inhibitor of ATX, administered either pre-anoxia or post-anoxia. Hydraulic permeability (Lp) of rat mesenteric post-capillary venules was evaluated after IRI, with and without ATX inhibition. Lastly, Lp was evaluated after the administration of ATX alone. RESULTS: Anoxia-reoxygenation increased monolayer permeability 4-fold (p < 0.01). Monolayer permeability was reduced to baseline similarly in both the pre-anoxia and post-anoxia ATX inhibition groups (each p < 0.01, respectively). Lp was attenuated by 24% with ATX inhibition (p < 0.01). ATX increased Lp from baseline in a dose dependent manner (p < 0.05). CONCLUSIONS: Autotaxin inhibition attenuated increases in endothelial monolayer permeability during A-R in vitro and hydraulic permeability during IRI in vivo. Targeting ATX may be especially beneficial by limiting its downstream mediators that contribute to mechanisms associated with endothelial permeability. ATX inhibitors may therefore have potential for pharmacotherapy during IRI.