Phosphodiesterase Inhibitor Research Articles

Placenta-anchored tadalafil liposomes rescues intrauterine growth restriction through continuous placental blood perfusion improvement

Physiological or pathological hypoperfusion of the placenta is one of the main causes of intrauterine growth restriction (IUGR) which poses a significant risk to the health of the fetus and newborn. Tadalafil, a 5-type phosphodiesterase inhibitor, has previously been found to improve the symptoms of IUGR in various clinical studies. Unfortunately, its clinical utility is hindered by its limited water solubility, rapid metabolism, and lack of specific distribution in target tissues rendering tadalafil unable to maintain long-term placental perfusion. In this study, iRGD-modified tadalafil-loaded liposomes (iRGD-lipo@Tad) featuring a size of approximately 480 nm were designed to rectify the shortcomings of tadalafil. The prepared iRGD-lipo@Tad exhibited superior stability, sustained drug release capacity, and low cytotoxicity. The fluorescence study, tissue slice study, and drug biodistribution study together demonstrated the placenta-anchored ability of iRGD-modified liposomes. This was achieved by a dual approach consisting of the iRGD-mediated placenta-targeting effect and special particle size-mediated placenta resident effect. The pharmacokinetic study revealed a significant improvement in the in vivo process of tadalafil encapsulated by the iRGD-modified liposomes. In comparison to the tadalafil solution, the peak plasma concentration of iRGD-lipo@Tad was significantly increased, and the area under the curve was increased by about 7.88 times. In the pharmacodynamic study, iRGD-lipo@Tad achieved a continuous and efficient improvement of placental blood perfusion. This was achieved by decreasing the ratio of plasma soluble fms-like tyrosine kinase to placental growth factor and increasing the levels of cyclic guanosine monophosphate and nitric oxide. Consequently, iRGD-lipo@Tad resulted in a significant increase in embryo weight and a reduction in the miscarriage rate of N-Nitro-L-arginine methyl ester-induced IUGR pregnant mice without detectable toxicity. In summary, the nanotechnology-assisted therapy strategy presented here not only overcomes the limitations of tadalafil in the clinical treatment of IUGR but also offers new avenues to address the treatment of other placenta-originated diseases.

(029) Safety and Efficacy of Botulinum Neurotoxin in the Treatment of Erectile Dysfunction Refractory to Phosphodiesterase Inhibitors: Results of a Randomized Controlled Trial

Abstract Introduction There has been recent interest in the use of botulinum neurotoxin (BoNT) in the field of Andrology, whereby it has been investigated in the treatment of penile retraction and premature ejaculation. Objective To evaluate the safety and efficacy of intracavernosal BoNT-A injection in the treatment of patients with erectile dysfunction (ED) refractory to oral phosphodiesterase inhibitors (PDE5Is). Methods A double-blind randomized placebo-controlled prospective comparative study conducted at one center and involved 70 patients with ED refractory to PDE5Is. At baseline, the following data were collected: erection hardness score (EHS), peak systolic velocity (PSV), end diastolic velocity (EDV), sexual health inventory for men (SHIM), and the sexual encounter profile 2&3 (SEP-2&3) questionnaires. Treatment group (n = 35) received a single ICI of 100 units of BoNT-A in 2 ml of saline and control group (n = 35) received a single ICI of 2 ml of saline. EHS, PSV, and EDV were assessed at 2 weeks post treatment. SHIM, SEP-2, SEP-3, and global assessment questionnaire (GAQ-Q1&Q2) were completed at 2-, 6-, and 12-weeks post treatment. Results Two weeks post treatment, the treatment group showed a statistically significant improvement in the mean EHS, PSV, EDV, and GAQ-Q1 positive responders (p < 0.001) compared to the control group. At 6- and 12-weeks post treatment, the treatment group showed a statistically significant improvement in the SHIM scores, SEP-2, and GAQ-Q1&Q2 positive responders compared to the control group. At 6 weeks, where there was a 5-point improvement in the mean SHIM score of the treatment group (10±5.9 from 5.4±1.7 at baseline) versus no improvement in the placebo group, 18 patients in the treatment group (53%) were able to have an erection hard enough for vaginal penetration versus only one patient in the control group. Conclusions BoNT-A is safe and effective as a potential treatment for ED refractory to PDE5I therapy. Disclosure No.

A proof of concept phase II study with the PDE-4 inhibitor roflumilast in patients with mild cognitive impairment or mild Alzheimer’s disease dementia (ROMEMA): study protocol of a double-blind, randomized, placebo-controlled, between-subjects trial

BackgroundResearch into the neurobiological underpinnings of learning and memory has demonstrated the cognitive-enhancing effects associated with diverse classes of phosphodiesterase (PDE) inhibitors. Specific PDE inhibitors have been identified to improve neuronal communication through selective inhibition of PDE activity. Roflumilast, a PDE4 inhibitor, has demonstrated efficacy in enhancing episodic memory in healthy adults and elderly participants with pronounced memory impairment, indicative of amnestic mild cognitive impairment (aMCI). In alignment with these findings, the present protocol aims to provide a proof of concept phase II of the potential of roflumilast to aid patients diagnosed with (a)MCI or mild Alzheimer’s disease (AD) dementia.MethodsThe study will be conducted according to a double-blind, randomized placebo-controlled, between-subjects design. Participants with (a)MCI and mild AD dementia will be recruited through the Memory Clinic at the Maastricht University Medical Centre + (MUMC +) in Maastricht, the Netherlands, alongside outreach through regional hospitals, and social media. The study will have three arms: placebo, 50 μg roflumilast, and 100 μg roflumilast, with a treatment duration of 24 weeks. The primary outcome measure will focus on the assessment of episodic memory, as evaluated through participants’ performance on the 15-word Verbal Learning Task (VLT). Our secondary objectives are multifaceted, including an exploration of various cognitive domains. In addition, insights into the well-being and daily functioning of participants will be investigated through interviews with both the participants and their (informal) caregivers, we are interested in the well-being and daily functioning of the participants.DiscussionThe outcomes of the present study aim to elucidate the significance of the PDE4 inhibition mechanism as a prospective therapeutic target for enhancing cognitive function in individuals with (a)MCI and mild AD dementia. Identifying positive effects within these patient cohorts could extend the relevance of this treatment to encompass a broader spectrum of neurological disorders.Trial registrationThe Medical Ethics Committee of MUMC + granted ethics approval for the 4th version of the protocol on September 10th, 2020. The trial was registered at the European Drug Regulatory Affairs Clinical Trials (EudraCT) registered on the 19th of December 2019 (https://www.clinicaltrialsregister.eu/ctr-search/trial/2019-004959-36/NL) and ClinicalTrial.gov (NCT04658654, https://clinicaltrials.gov/study/NCT04658654?intr=roflumilast&cond=mci&rank=1) on the 8th of December 2020. The Central Committee on Research Involving Human Subjects (CCMO) granted approval on the 30th of September 2020.

Retraction: Abdallah MS, Mosalam EM, Hassan A, etal. Pentoxifylline as an adjunctive in treatment of negative symptoms in chronic schizophrenia: A double-blind, randomized, placebo-controlled trial. CNS Neurosci. Ther. 2023;29:354-364 (https://doi.org/10.1111/cns.14010).

Retraction: Abdallah MS, Ramadan AN, Omara-Reda H, etal. Double-blind, randomized, placebo-controlled pilot study of the phosphodiesterase-3 inhibitor cilostazol as an adjunctive to antidepressants in patients with major depressive disorder. CNS Neurosci. Ther. 2021;27:1540-1548 (https://doi.org/10.1111/cns.13731) The above article, published online on September 21, 2021 in Wiley Online Library (wileyonlinelibrary.com) has been retracted by agreement between the journal's Editor-in-Chief, Xiaoming Hu, and John Wiley and Sons Ltd. Following publication, multiple concerns were raised by a third party about the integrity of the clinical trial. An investigation revealed significant issues regarding the reliability of the reported data. As a result, the Editor-in-Chief no longer has confidence in the validity of the results presented in this article.

Cilostazol for peripheral arterial disease - a position paper from the Italian Society for Angiology and Vascular Medicine.

Cilostazol is a quinolinone-derivative selective phosphodiesterase inhibitor and is a platelet-aggregation inhibitor and arterial vasodilator for the symptomatic treatment of intermittent claudication (IC). Cilostazol has been shown to improve walking distance for patients with moderate to severe disabling intermittent claudication who do not respond to exercise therapy and who are not candidates for vascular surgical or endovascular procedures. Several studies evaluated the pharmacological effects of cilostazol for restenosis prevention and indicated a possible effect on re-endothelialization mediated by hepatocyte growth factor and endothelial precursor cells, as well as inhibiting smooth muscle cell proliferation and leukocyte adhesion to endothelium, thereby exerting an anti-inflammatory effect. These effects may suggest a potential effectiveness of cilostazol in preventing restenosis and promoting the long-term outcome of revascularization interventions. This review aimed to point out the role of cilostazol in treating patients with peripheral arterial disease, particularly with IC, and to explore its possible role in restenosis after lower limb revascularization.

Single-dose Tadalafil Reduces Opening Urethral Pressure: A Randomized, Double-blind, Placebo-controlled, Crossover Trial in Healthy Women

Introduction and HypothesisPhosphodiesterase enzymes are widely distributed in female urogenital tissues. Yet, the understanding of their physiological roles and the impact of phosphodiesterase inhibitors on lower urinary tract symptoms in women remains limited. Current hypotheses are conflicting: one suggests that vasodilation might expand the periurethral vascular plexus, leading to increased urethral pressure, whereas the other proposes a relaxation of urethral musculature, resulting in decreased pressure. To further clarify this, we investigated the effect of tadalafil on the opening urethral pressure and voiding function in healthy women.MethodsWe conducted a randomized, double-blind, placebo-controlled crossover trial involving 24 healthy women. Participants were randomly assigned to receive a single dose of tadalafil (40 mg) or placebo during their initial visit and then switched to the alternative treatment during their second visit. Opening urethral pressure was measured with urethral pressure reflectometry during both resting and squeezing conditions of the pelvic floor. Subsequently, voiding parameters were recorded.ResultsCompared with placebo, a single dose of tadalafil significantly reduced opening urethral pressure during both resting (-6.8 cmH20; 95% confidence interval [CI], -11.8 to -1.9; p = 0.009) and squeezing conditions (-8.8 cmH20; 95% CI, -14.6 to -3.1; p = 0.005). Voiding parameters did not show significant differences (average flow rate: -0.8 ml/s [95% CI, -2.0 to 0.4; p = 0.2]; maximum flow rate: -1.7 ml/s [95% CI, -4.8 to 1.5; p = 0.3]).ConclusionsA single dose of 40 mg tadalafil moderately reduced urethral pressure in healthy women, without affecting voiding parameters. The clinical implications of this are yet to be determined.

Circulating Monocytes Are Predictive and Responsive in Moderate-to-Severe Plaque Psoriasis Subjects Treated with Apremilast

Monocytes play a critical role in the inflammation associated with psoriasis, and their abnormalities have been reported as biomarkers of cardiovascular event risk, a psoriasis comorbidity. Monocytic cells in chronic inflammatory disorders express elevated levels of cAMP phosphodiesterase. Restoring cAMP levels using the oral cAMP phosphodiesterase-4 inhibitor, apremilast, improves clinical outcomes for a subset of patients with psoriasis. We asked whether aberrant monocyte subsets or transcriptomic pathways can function as biomarkers of psoriasis endotypes that can predict enhanced clinical responses to cAMP phosphodiesterase inhibition. A 16-week open-label study of 22 patients with monocyte flow cytometric and transcriptomic analysis was performed. Subjects with elevated hyperadhesive monocyte doublets at baseline were more likely to be responders to apremilast (P < .0001); 82% of subjects with elevated hyperadhesive monocyte doublets achieved 50% reduction in PASI compared with 46% in those without elevated doublets. We observed a significant reduction in hyperadhesive monocyte-containing doublets and monocyte-platelet aggregates, suggesting an effect of apremilast on the adhesiveness of blood monocytes during chronic inflammation. Monocyte differentially expressed gene transcripts predictive of clinical response uncovered pharmacoendotypes with distinct patterns of nucleotide metabolism, energetics, and differentiation. Further study to understand the basis of drug responsiveness and to develop an apremilast psoriasis treatment algorithm using monocyte-refined gene expression is required to validate and become practical in clinical use, offering patients a test that personalizes their likelihood of clinical response.

A conserved trypanosomatid differentiation regulator controls substrate attachment and morphological development in Trypanosoma congolense.

Trypanosomatid parasites undergo developmental regulation to adapt to the different environments encountered during their life cycle. In Trypanosoma brucei, a genome wide selectional screen previously identified a regulator of the protein family ESAG9, which is highly expressed in stumpy forms, a morphologically distinct bloodstream stage adapted for tsetse transmission. This regulator, TbREG9.1, has an orthologue in Trypanosoma congolense, despite the absence of a stumpy morphotype in that parasite species, which is an important cause of livestock trypanosomosis. RNAi mediated gene silencing of TcREG9.1 in Trypanosoma congolense caused a loss of attachment of the parasites to a surface substrate in vitro, a key feature of the biology of these parasites that is distinct from T. brucei. This detachment was phenocopied by treatment of the parasites with a phosphodiesterase inhibitor, which also promotes detachment in the insect trypanosomatid Crithidia fasciculata. RNAseq analysis revealed that TcREG9.1 silencing caused the upregulation of mRNAs for several classes of surface molecules, including transferrin receptor-like molecules, immunoreactive proteins in experimental bovine infections, and molecules related to those associated with stumpy development in T. brucei. Depletion of TcREG9.1 in vivo also generated an enhanced level of parasites in the blood circulation consistent with reduced parasite attachment to the microvasculature. The morphological progression to insect forms of the parasite was also perturbed. We propose a model whereby TcREG9.1 acts as a regulator of attachment and development, with detached parasites being adapted for transmission.

The Role of Cilostazol, a Phosphodiesterase-3 Inhibitor, in the Development of Atherosclerosis and Vascular Biology: A Review with Meta-Analysis.

Atherosclerotic cardiovascular disease (ASCVD) stands as the leading global cause of mortality. Addressing this vital and pervasive condition requires a multifaceted approach, in which antiplatelet intervention plays a pivotal role, together with antihypertensive, antidiabetic, and lipid-lowering therapies. Among the antiplatelet agents available currently, cilostazol, a phosphodiesterase-3 inhibitor, offers a spectrum of pharmacological effects. These encompass vasodilation, the impediment of platelet activation and aggregation, thrombosis inhibition, limb blood flow augmentation, lipid profile enhancement through triglyceride reduction and high-density lipoprotein cholesterol elevation, and the suppression of vascular smooth muscle cell proliferation. However, the role of cilostazol has not been clearly documented in many guidelines for ASCVD. We comprehensively reviewed the cardiovascular effects of cilostazol within randomized clinical trials that compared it to control or active agents and involved individuals with previous coronary artery disease or stroke, as well as those with no previous history of such conditions. Our approach demonstrated that the administration of cilostazol effectively reduced adverse cardiovascular events, although there was less evidence regarding its impact on myocardial infarction. Most studies have consistently reported its favorable effects in reducing intermittent claudication and enhancing ambulatory capacity in patients with peripheral arterial disease. Furthermore, cilostazol has shown promise in mitigating restenosis following coronary stent implantation in patients with acute coronary syndrome. While research from more diverse regions is still needed, our findings shed light on the broader implications of cilostazol in the context of atherosclerosis and vascular biology, particularly for individuals at high risk of ASCVD.

The role of Doppler ultrasound in the evaluation of penile haemodynamics—A sonographer's guide to the documentation of vasculogenic erectile dysfunction

AbstractVasculogenic erectile dysfunction (ED) is the most common form of ED affecting the male population. Once the first line investigation for erectile dysfunction, penile Doppler ultrasound examinations have reduced in number following the introduction of oral phosphodiesterase inhibitors as a treatment method. As such, skilled professionals versed in the performance of these examinations are dwindling. This skill deficit is compounded by the lack of standardisation that exists in the performance and interpretation of penile haemodynamics relative to impotence of vascular origin. Despite the success of pharmacological agents in the treatment of vasculogenic dysfunction, penile Doppler examinations are still relevant in the assessment of ED in non‐responders, and those patients in which pelvic surgery or trauma has altered the normal erectile mechanism. Growing evidence in the literature also suggests that vasculogenic ED may be an early indicator of systemic vascular disease and therefore prognostic of future cardiovascular events. Considering this, the relevance of Doppler assessment of penile haemodynamics with ultrasound should not be underestimated. This article will introduce the sonographer to advanced vascular anatomy of the penis, pathophysiology of erectile function and the principles of normal and pathological penile haemodynamic patterns. It also aims to suggest a standardised protocol for the performance of penile Doppler ultrasound relative to primary vasculogenic ED and reduce the amount of variability that exits between operators. As such the sonographer can make a significant contribution to patient management pathways.

(402) Peyronie's Disease Treatment- Active Vs. Stable Phase- Retrospective Review of Cases

Abstract Introduction Peyronie's disease (PD) may be treated with collagenase clostridium histolyticum (CCH) during the stable phase. However, the effectiveness and safety of this treatment during the active phase remain unclear. To address this, we investigated and compared the outcomes of patients receiving treatment in the active phase versus the stable phase of PD. Objective To assess the effectiveness and safety of CCH treatment in patients diagnosed with PD during the active phase. Methods A retrospective review was conducted on men who underwent at least one cycle of CCH injections for PD with a single fellowship-trained urologist between 2017 and 2023. Active PD was defined as occurring within one year from the onset of symptoms. The severity of penile curvature was measured at the point of maximal curvature and assessed at baseline and after each CCH cycle. In addition to the CCH treatment, patients were prescribed daily phosphodiesterase inhibitors (PDEi) and coenzyme-Q10 (CoQ-10). The treatment response was defined as any improvement in curvature from baseline to the final assessment. The characteristics and outcomes of patients were compared between those with active and stable PD. Results Of 107 patients who underwent CCH treatment, 75 were diagnosed with stable PD and 32 with active PD. There were no significant differences observed between the two groups in terms of age (58.1 vs. 57.9 years, p = 0.89), baseline curvature (58.4 vs. 60.5 degrees, p = 0.60), or the number of CCH cycles received (6.6 vs. 6.3 cycles, p = 0.57). Among the active PD patients, 26 (81.2%) experienced an improvement in curvature, which was comparable to the stable PD group (58 (77.3%), p = 0.85). There were no significant differences in the degree of curvature improvement (14.4 vs. 14.0 degrees, p = 0.91) or the percentage of improvement from baseline (22.67% vs. 24.05%, p = 0.86) between the active and stable PD patients. In the subset of patients who showed an improvement in curvature angle, there was no notable distinction in the percentage of improvement from baseline between the stable and active phases (37.4% vs 34.8%, p=0.63). Among the treated patients, we observed two cases of potential penile fractures in the stable phase. All adverse events were conservatively managed. Conclusions Patients treated with CCH during the active phase achieved comparable outcomes to those in the stable phase. There were no additional adverse events in the active phase treatment group. These data suggest that early active phase treatment yields similar effectiveness as treatment administered during the stable phase. Treatment during the active phase could be a disease modifier and may change the course of progression. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Endo, Roman Health.

(287) A Patient's Journey with Erectile Dysfunction: Prediction Progression to Penile Implant

Abstract Introduction Inflatable penile prosthesis (IPP) is seen as the gold standard for surgical treatment for ED, specifically for patients that are not amenable to lifestyle changes or oral medications. Objective This study aims to explore which patients progress to seeking treatment with an IPP along their journey with erectile dysfunction. Methods This retrospective study identified patients with ED as a chief complaint during the primary visit or follow-up from 2009-2022. If patients eventually progressed to treatment with IPP, data was collected to find common features and analyzed. Results Of our cohort of 361 men presenting with erectile dysfunction (ED), 21 men progressed to the placement of an inflatable penile prosthesis (IPP). 20 men classified as non-Hispanic, with 13 white, 6 African American/black, and 1 Asian males. Only 1 man was Hispanic. 5 men had either hypertension (n = 11), hyperlipidemia (n = 10), or DM (n = 3), with 6 having both hypertension and hyperlipemia, 1 with hypertension and diabetes, and 1 with hypertension, hyperlipidemia, and diabetes. Median age of the group at surgery was 76 years (IQR: 71 – 82), with median time from initial presentation to surgery of 12 (IQR = 11.5-27.5) months. N = 10 men had trialed oral phosphodiesterase inhibitor type 5 (PDE-5i) therapy, and 7 men failed intracavernosal injection (ICI) therapy. 8 men had been treated for hypogonadal symptoms with testosterone replacement therapy (TRT). Of patients who had data available on their reason for IPP placement, indications included were Peyronie’s disease inhibiting intercourse (8/21), longstanding ED refractory to medical therapy (4/21), post-prostatectomy ED (4/21), history of priapism requiring surgical intervention (1/21), and history of spinal cord tumor (1/21). Among those treated with IPP, the median patient waited almost 1 year from initial presentation following failure with PDE5i, ICI, and TRT. 17/21 men reported satisfaction after IPP treatment. In those who progressed to IPP, the majority of indications were organic forms of ED (Peyronie’s disease, neurogenic, surgery). Conclusions Only 5.8% of men in this cohort went on to proceed with an IPP. In summary, our results indicate that IPP is best suited for those presenting with organic ED who have failed more conservative management techniques. Further studies are needed to assess why so few men go on to proceed with an IPP and wait an average of 2 years. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Consultant for AbbVie, Marius, Tolmar, Endo, Petros, Boston Scientific, Coloplast Investor: Sprout.

C-terminal peptide of preproorexin enhances brain-derived neurotrophic factor expression in rat cerebrocortical cells and recognition memory in mice

During the production of orexin A and B from preproorexin, a common precursor protein, in hypothalamic orexin neurons, C-terminal peptide (herein called preproorexin C-peptide) is concomitantly produced via post-translational processing. The predicted three-dimensional structure of preproorexin C-peptide is similar among mammalian species, suggestive of a conserved function in the mammalian brain. However, C-peptide has long been regarded as a non-functional peptide. We herein examined the effects of rat and/or mouse preproorexin C-peptide on gene expression and cell viability in cultured rat cerebrocortical cells and on memory behavior in C57BL/6J mice. Rat and mouse C-peptides both increased brain-derived neurotrophic factor (Bdnf) mRNA levels. Moreover, C-peptide enhanced high K+-, glutamate-, and BDNF-induced increases in Bdnf mRNA levels without affecting forskolin-induced Bdnf expression. H-89, a protein kinase A inhibitor, blocked C-peptide-induced Bdnf expression, whereas rolipram, a phosphodiesterase inhibitor, enhanced this effect. Intracellular cyclic AMP concentrations were elevated by C-peptide. These results demonstrate that preproorexin C-peptide promoted Bdnf mRNA expression by a cyclic AMP-dependent mechanism. Eleven amino acids at the N terminus of rat preproorexin C-peptide exerted similar effects on Bdnf expression as full-length preproorexin C-peptide. Preproorexin C-peptide also exerted protective effects against CoCl2-induced neuronal cell death. An intracerebroventricular injection of mouse preproorexin C-peptide induced c-fos and Bdnf expression in the cerebral cortex and hippocampus and enhanced novel object recognition memory in mice. Collectively, the present results show that preproorexin C-peptide is a functional substance, at least in some pharmacological and neuronal settings.

Abstract WP194: Quantified Effects of Intra-Arterial Vasodilatory Therapy for Cerebral Vasospasm

Introduction: Cerebral vasospasm is a major cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (aSAH). Though used routinely in clinical practice, objective metrics to evaluate effectiveness of intra-arterial vasodilatory treatment (IAT) have not been identified. To quantify effects of IAT on flow dynamics in cerebral vasospasm, we retrospectively compared Lindegaard ratios (LR) of aSAH patients pre-and post-IAT. Methods: Subjects included 24 aSAH patients undergoing IAT in the bilateral middle cerebral arteries (MCA) for cerebral vasospasm, diagnosed by standard clinical and radiographic criteria. Subjects were excluded if balloon angioplasty was performed prior to/within 2 days of the index procedure. All subjects received 10 mg IA milrinone, a non-catecholamine phosphodiesterase inhibitor drug, per MCA. Transcranial doppler (TCD) ultrasound was measured pre-IAT (D0) and at D+1 and D+2 post-IAT. LR was calculated as the ratio of mean flow velocities in the middle cerebral artery (MCA) to the ipsilateral extracranial internal carotid artery. Standard threshold for vasospasm is defined as LR&gt;3. Results: Right and left LR were aggregated, total N=48. Average pre-IAT LR was 2.96 (R 2.67/L 3.25±1.29). Post-IA LR were 2.72±1.12 and 3.15±1.55 at D+1 and D+2, respectively. Subjects with pre-IA LR&gt;3 showed an average LR decrease of 21% post-IAT D+1 (p=0.01) and an 8% decrease at D+2 (p=0.16) [Fig.1A]. Subjects with pre-IAT&lt;3 experienced an average LR increase of 28% by D+2 (p=0.02) [Fig 1B]. Conclusion: Subjects with TCD confirmed vasospasm (LR&gt;3) at D0 showed a significant improvement in cerebral blood flow one day after therapy. Subjects who did not meet TCD threshold for vasospasm (LR&lt;3) showed little change one day post-IAT but worsening cerebral blood flow by day two post-IAT. Further study is needed to determine whether LR can be used to predict benefit or objectively assess effectiveness of IAT in aSAH patients with cerebral vasospasm.

Emerging phosphodiesterase inhibitors for treatment of neurodegenerative diseases.

Neurodegenerative diseases (NDs) cause progressive loss of neuron structure and ultimately lead to neuronal cell death. Since the available drugs show only limited symptomatic relief, NDs are currently considered as incurable. This review will illustrate the principal roles of the signaling systems of cyclic adenosine and guanosine 3',5'-monophosphates (cAMP and cGMP) in the neuronal functions, and summarize expression/activity changes of the associated enzymes in the ND patients, including cyclases, protein kinases, and phosphodiesterases (PDEs). As the sole enzymes hydrolyzing cAMP and cGMP, PDEs are logical targets for modification of neurodegeneration. We will focus on PDE inhibitors and their potentials as disease-modifying therapeutics for the treatment of Alzheimer's disease, Parkinson's disease, and Huntington's disease. For the overlapped but distinct contributions of cAMP and cGMP to NDs, we hypothesize that dual PDE inhibitors, which simultaneously regulate both cAMP and cGMP signaling pathways, may have complementary and synergistic effects on modifying neurodegeneration and thus represent a new direction on the discovery of ND drugs.

New Dual Inhibitors of Tyrosyl-DNA Phosphodiesterase 1 and 2 Based on Deoxycholic Acid: Design, Synthesis, Cytotoxicity, and Molecular Modeling.

Deoxycholic acid derivatives containing various heterocyclic functional groups at C-3 on the steroid scaffold were designed and synthesized as promising dual tyrosyl-DNA phosphodiesterase 1 and 2 (TDP1 and TDP2) inhibitors, which are potential targets to potentiate topoisomerase poison antitumor therapy. The methyl esters of DCA derivatives with benzothiazole or benzimidazole moieties at C-3 demonstrated promising inhibitory activity in vitro against TDP1 with IC50 values in the submicromolar range. Furthermore, methyl esters 4d-e, as well as their acid counterparts 3d-e, inhibited the phosphodiesterase activity of both TDP1 and TDP2. The combinations of compounds 3d-e and 4d-e with low-toxic concentrations of antitumor drugs topotecan and etoposide showed significantly greater cytotoxicity than the compounds alone. The docking of the derivatives into the binding sites of TDP1 and TDP2 predicted plausible binding modes of the DCA derivatives.

The mechanism of 25-hydroxycholesterol-mediated suppression of atrial β1-adrenergic responses.

25-Hydroxycholesterol (25HC) is a biologically active oxysterol, whose production greatly increases during inflammation by macrophages and dendritic cells. The inflammatory reactions are frequently accompanied by changes in heart regulation, such as blunting of the cardiac β-adrenergic receptor (AR) signaling. Here, the mechanism of 25HC-dependent modulation of responses to β-AR activation was studied in the atria of mice. 25HC at the submicromolar levels decreased the β-AR-mediated positive inotropic effect and enhancement of the Ca2+ transient amplitude, without changing NO production. Positive inotropic responses to β1-AR (but not β2-AR) activation were markedly attenuated by 25HC. The depressant action of 25HC on the β1-AR-mediated responses was prevented by selective β3-AR antagonists as well as inhibitors of Gi protein, Gβγ, G protein-coupled receptor kinase 2/3, or β-arrestin. Simultaneously, blockers of protein kinase D and C as well as a phosphodiesterase inhibitor did not preclude the negative action of 25HC on the inotropic response to β-AR activation. Thus, 25HC can suppress the β1-AR-dependent effects via engaging β3-AR, Gi protein, Gβγ, G protein-coupled receptor kinase, and β-arrestin. This 25HC-dependent mechanism can contribute to the inflammatory-related alterations in the atrial β-adrenergic signaling.

Phosphodiesterases Mediate the Augmentation of Myogenic Constriction by Inhibitory G Protein Signaling and is Negatively Modulated by the Dual Action of RGS2 and 5.

G protein regulation by regulators of G protein signaling (RGS) proteins play a key role in vascular tone maintenance. The loss of Gi/o and Gq/11 regulation by RGS2 and RGS5 in non-pregnant mice is implicated in augmented vascular tone and decreased uterine blood flow (UBF). RGS2 and 5 are closely related and co-expressed in uterine arteries (UA). However, whether and how RGS2 and 5 coordinate their regulatory activities to finetune G protein signaling and regulate vascular tone are unclear. Here, we determined how the integrated activity of RGS2 and 5 modulates vascular tone to promote UBF. Using ultrasonography and pressure myography, we examined uterine hemodynamics and myogenic tone (MT) of UA of wild type (WT), Rgs2-/-, Rgs5-/-, and Rgs2/5 dbKO mice. We found that MT was reduced in Rgs5-/- relative to WT or Rgs2-/- UA. Activating Gi/o with dopamine increased, whereas exogenous cAMP decreased MT in Rgs5-/- UA to levels in WT UA. Dual deletion of Rgs2 and 5 abolished the reduced MT due to the absence of Rgs5 and enhanced dopamine-induced Gi/o effects in Rgs2/5 dbKO UA. Conversely, and as in WT UA, Gi/o inhibition with pertussis toxin or exogenous cAMP decreased MT in Rgs2/5 dbKO to levels in Rgs5-/- UA. Inhibition of phosphodiesterases (PDE) concentration-dependently decreased and normalized MT in all genotypes, and blocked dopamine-induced MT augmentation in Rgs2-/-, Rgs5-/-, and Rgs2/5 dbKO UA. We conclude that Gi/o augments UA MT in the absence of RGS2 by a novel mechanism involving PDE-mediated inhibition of cAMP-dependent vasodilatation..

Continuous direct intraarterial treatment of meningitis-induced vasospasm in a pediatric patient: illustrative case.

Bacterial meningitis-induced ischemic stroke continues to cause significant long-term complications in pediatric patients. The authors present a case of severe right internal carotid artery terminus and M1 segment vasospasm in a 9-year-old with an infected cholesteatoma, which was refractory to multiple intraarterial treatments with verapamil and milrinone. This is the first report of continuous intraarterial antispasmodic treatment in a pediatric patient as well as the first report of continuous treatment in an awake and extubated patient. Arterial narrowing was successfully treated by continuous direct intraarterial administration of both a calcium channel blocker (verapamil) and a phosphodiesterase-3 inhibitor (milrinone). The patient recovered remarkably well and was discharged home with no neurological deficit (National Institutes of Health Stroke Scale score 0) and ambulatory without assistance after 22 days. The authors report a promising outcome of this technique performed in a pediatric patient. This represents a novel treatment option for the prevention of stroke in pediatric bacterial meningitis. Continuous, direct intraarterial administration of antispasmodic medications can successfully prevent long-term neurological deficit in pediatric meningitis-associated vasospasm. The described method has the potential to significantly improve outcomes in severe pediatric meningitis-associated vasospasm.

Effect of Extender Supplementation With Caffeine on Arabian Stallion’s Semen Quality After Freezing

In the current study, we aimed to investigate the effect of adding different levels of caffeine to the diluent on the Arabian stallion&amp;rsquo;s sperm quality post cryopreservation. Semen cryopreservation is an essential part of artificial insemination in Arabian horses. In most of cases, the stallion selection is based on desirable phenotypic and physical traits rather than on fertility. This approach may have resulted in the propagation of low-fertility genotypes that are unable to withstand the various stresses associated with cryopreservation such as freezing-thawing stress, oxidative stress, and osmotic stress. Caffeine has been shown to act as a phosphodiesterase inhibitor which may increase the level of cAMP in sperm and subsequently, increase the formation of adenosine triphosphate, which is important for sperm motility. Because it contains xanthine and theobromine, caffeine has antioxidant properties that increase sperm motility and their fertilizability. Five healthy stallions aged 4 to 10 years have been used for semen collection. Semen collections has been done twice weekly by artificial vagina. The ejaculates were evaluated for general progressive motility and sperm concentration. Sperm concentration and motility were determined using the CASA system (ISAS program, Prosser R+D, Paterna, Valencia, Spain). Samples with a minimum concentration of 200 &amp;times; 106 sperm/ml and motility &amp;gt; 60% used for this study. The filtered semen of each ejaculate was diluted (1:1) and divided into 4 aliquots. The aliquots were centrifuged at 800 g for 10 minutes, the seminal plasma was removed, and each sample was re-suspended with FH-20 (0) without any supplementation as a control or with caffeine at a concentration of 0.5 mM, 1 mM, 3 mM or 5 mM. The final semen concentration after dilution was 200 &amp;times; 106 sperm/ml. All samples were assessed before freezing in liquid nitrogen. The frozen thawed semen was assessed for general and progressive motility and then evaluated using the ISAS program and assessed for plasma membrane integrity, morphology defects, acrosome integrity, and viability. Descriptive analyses were determined for the evaluated variables. Statistical comparisons between groups were performed with one-way analysis of variance (ANOVA) (p &amp;lt; 0.05). The addition of 1 mM caffeine to the extender gave better results in total motility (TM), progressive motility (PM) and vitality. However, all studied caffeine concentrations had good effects on straight line velocity (VSL), straightness (STR), linearity (LIN), wobble (WOB) and HOST with no effects on acrosome integrity. It could be concluded that caffeine has a beneficial effect on Arabian stallion semen cryopreservation when added at a concentration of 1 mM to the extender.