Research progress on genetic variants of PDE4D and susceptibility to stroke in Chinese population / 中华医学遗传学杂志

The pathogenesis of stroke is complex, with genetic risk factors as one of the main factors. The genetic variants of phosphodiesterase 4D (PDE4D) was significantly associated with the susceptibility to ischemic stroke (IS) in Caucasian population, but its association with the susceptibility to stroke in Chinese population is unclear. This article is intended to review the research on the association between PDE4D genetic variants and stroke susceptibility in Chinese population, aiming to further optimize the relevant research programs and provide reference for the prevention and treatment of stroke in China.

Pharmacotherapy for chronic obstructive pulmonary disease

The goals of management of stable chronic obstructive pulmonary disease (COPD) are to reduce both current symptoms and future risks with minimal side effects from treatment. Identification and reduction of exposure to risk factors are important in the treatment and prevention of COPD. Appropriate pharmacologic therapy can reduce symptoms and exacerbations, and improve health status and exercise tolerance. To date, none of the existing medications for COPD has been shown to modify disease progression or reduce mortality. The classes of medication are bronchodilators including beta2-agonist, anticholinergics and anti-inflammatory drug including inhaled corticosteroid and phosphodiesterase-4 inhibitor such as roflumilast. Each treatment regimen needs to be individualized as the relationship between severity of symptoms, airflow limitation and severity of exacerbation can differ between patients.

The Phosphodiesterase 4 Inhibitor Roflumilast Protects against Cigarette Smoke Extract-Induced Mitophagy-Dependent Cell Death in Epithelial Cells / 결핵및호흡기질환

BACKGROUND: Recent studies show that mitophagy, the autophagy-dependent turnover of mitochondria, mediates pulmonary epithelial cell death in response to cigarette smoke extract (CSE) exposure and contributes to the development of emphysema in vivo during chronic cigarette smoke (CS) exposure, although the underlying mechanisms remain unclear. METHODS: In this study, we investigated the role of mitophagy in the regulation of CSE-exposed lung bronchial epithelial cell (Beas-2B) death. We also investigated the role of a phosphodiesterase 4 inhibitor, roflumilast, in CSE-induced mitophagy-dependent cell death. RESULTS: Our results demonstrated that CSE induces mitophagy in Beas-2B cells through mitochondrial dysfunction and increased the expression levels of the mitophagy regulator protein, PTEN-induced putative kinase-1 (PINK1), and the mitochondrial fission protein, dynamin-1-like protein (DRP1). CSE-induced epithelial cell death was significantly increased in Beas-2B cells exposed to CSE but was decreased by small interfering RNA-dependent knockdown of DRP1. Treatment with roflumilast in Beas-2B cells inhibited CSE-induced mitochondrial dysfunction and mitophagy by inhibiting the expression of phospho-DRP1 and -PINK1. Roflumilast protected against cell death and increased cell viability, as determined by the lactate dehydrogenase release test and the MTT assay, respectively, in Beas-2B cells exposed to CSE. CONCLUSION: These findings suggest that roflumilast plays a protective role in CS-induced mitophagy-dependent cell death.

Incidence of Adverse Effects and Discontinuation Rate between Patients Receiving 250 Micrograms and 500 Micrograms of Roflumilast: A Comparative Study / 결핵및호흡기질환

BACKGROUND: Roflumilast is the only approved oral phosphodiesterase-4 inhibitor for the treatment of severe chronic obstructive pulmonary disease (COPD) in patients with chronic bronchitis and a history of frequent exacerbations. The purpose of this study was to examine the incidence of adverse effects associated with roflumilast treatment in a real-world setting. Further, we compared the incidence of adverse effects and the discontinuation rate among patients receiving different doses. METHODS: We identified all outpatients diagnosed with COPD at Seoul St. Mary's Hospital between May 2011 and September 2016 and retrospectively reviewed their medical records. Roflumilast was prescribed to patients in doses of 500 µg and 250 µg. RESULTS: A total of 269 COPD patients were prescribed roflumilast in our hospital during the study period. Among them, 178 patients were treated with 500 µg and 91 patients were treated with 250 µg. The incidence of adverse effects was 38.2% in the 500 µg group and 25.3% in the 250 µg group (p=0.034). The discontinuation rate of roflumilast was 41.6% (n=74) in the 500 µg group and 23.1% (n=21) in the 250 µg group (p=0.003). When adjusted by age, sex, smoking status, and lung function, 500 µg dose was significantly associated with the discontinuation of roflumilast (odds ratio, 2.87; p < 0.001). CONCLUSION: There was a lower incidence of adverse effects and discontinuation among patients treated with 250 µg compared with 500 µg dose. Further studies regarding the optimal dose of roflumilast are required.

Relaxant and anti-inflammatory effect of two thalidomide analogs as PDE-4 inhibitors in pregnant rat uterus

The aim of this study was to evaluate the relaxant and anti-inflammatory effects of two thalidomide analogs as phosphodiesterase-4 (PDE-4) inhibitors in pregnant rat uterus. Uteri from Wistar female rats were isolated at 19 day of pregnancy. Uterine samples were used in functional studies to evaluate the inhibitory effects of the thalidomide analogs, methyl 3-(4-nitrophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4NO2PDPMe) and methyl 3-(4-aminophthalimido)-3-(3,4-dimethoxyphenyl)-propanoate (4APDPMe), on prostaglandin-F2α (PGF2α)-induced phasic, K⁺-induced tonic, and Ca²⁺-induced contractions. Accumulation of cAMP was quantified in uterine homogenates by ELISA. Anti-inflammatory effect was assessed by using ELISA for determination of the pro-inflammatory cytokines tumor necrosis factor-α (TNFα) and interleukin (IL)-1β, and anti-inflammatory IL-10, from uterine explants stimulated with lipopolysaccharide (LPS). Nifedipine, forskolin and rolipram were used as positive controls where required. Both thalidomide analogs induced a significant inhibition of the uterine contractions induced by the pharmaco- and electro-mechanic stimuli. Nifedipine and forskolin were more potent than the analogs to inhibit the uterine contractility, but these were more potent than rolipram, and 4APDPMe was equieffective to nifedipine. Thalidomide analogs increased uterine cAMP-levels in a concentration-dependent manner. The LPS-induced TNFα and IL-1β uterine secretion was diminished in a concentration-dependent fashion by both analogs, whereas IL-10 secretion was increased significantly. The thalidomide analogs induced utero-relaxant and anti-inflammatory effects, which were associated with the increased cAMP levels as PDE-4 inhibitors in the pregnant rat uterus. Such properties place these thalidomide analogs as potentially safe and effective tocolytic agents in a field that urgently needs improved pharmacological treatments, as in cases of preterm labor.

Specific Expression of Aplysia Phosphodiesterase 4 in Bag Cells Revealed by in situ Hybridization Analysis

Phosphodiesterases (PDEs) play a key role in the regulation of cyclic adenosine monophosphate (cAMP), which in turn mediates various cellular functions including learning and memory. We previously cloned and characterized three PDE4 isoforms (ApPDE4) from Aplysia kurodai. Using reverse transcription polymerase chain reaction (RT-PCR), we found that ApPDE4 isoforms are primarily expressed in the central nervous system. However, the detailed distribution of ApPDE4 mRNA in Aplysia individual ganglions was not evident. In this study, to determine the distribution of ApPDE4 mRNAs in Aplysia ganglions, we performed in situ hybridization (ISH) using a probe targeting ApPDE4, including the PDE catalytic domain. Interestingly, we found the strongest ISH-positive signals in the symmetrical bag cell clusters of the abdominal ganglion. The R2, R14, L7, L2 and L11 neurons in the abdominal ganglion, LP1 neuron in pleural ganglion, and metacerebral (MCC) neurons were ISH-positive. Mechanosensory neurons of the sensory cluster were also stained on the ventral aspect of the right and left pleural ganglia. Taken together, we found the detailed distribution of ApPDE4 mRNA in Aplysia ganglion and support their roles in serotonin (5-HT)-induced synaptic facilitation of Aplysia mechanosensory neurons.

Effect of a Dose-Escalation Regimen for Improving Adherence to Roflumilast in Patients with Chronic Obstructive Pulmonary Disease / 결핵및호흡기질환

BACKGROUND: The adverse effects of the phosphodiesterase-4 inhibitor roflumilast, appear to be more frequent in clinical practice than what was observed in chronic obstructive pulmonary disease (COPD) clinical trials. Thus, we designed this study to determine whether adverse effects could be reduced by starting roflumilast at half the dose, and then increasing a few weeks later to 500 microg daily. METHODS: We retrospectively investigated 85 patients with COPD who had taken either 500 microg roflumilast, or a starting dose of 250 microg and then increased to 500 microg. We analyzed all adverse events and assessed differences between patients who continued taking the drug after dose escalation and those who had stopped. RESULTS: Adverse events were reported by 22 of the 85 patients (25.9%). The most common adverse event was diarrhea (10.6%). Of the 52 patients who had increased from a starting dose of 250 microg roflumilast to 500 microg, 43 (82.7%) successfully maintained the 500 microg roflumilast dose. No difference in factors likely to affect the risk of adverse effects, was detected between the dose-escalated and the discontinued groups. Of the 26 patients who started with the 500 microg roflumilast regimen, seven (26.9%) discontinued because of adverse effects. There was no statistically significant difference in discontinuation rate between the dose-escalated and the control groups (p=0.22). CONCLUSION: Escalating the roflumilast dose may reduce treatment-related adverse effects and improve tolerance to the full dose. This study suggests that the dose-escalated regimen reduced the rate of discontinuation. However, longer-term and larger-scale studies are needed to support the full benefit of a dose escalation strategy.

Sex-dependent association of phosphodiesterase 4D gene polymorphisms with ischemic stroke in Henan Han population / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recent evidence has implicated the gene for phosphodiesterase 4D (PDE4D) as susceptibility gene for ischemic stroke (IS) in Icelandic population. However, there are few reports on the associations between PDE4D gene polymorphisms and IS in Chinese individuals. The present study aimed to investigate the possible association of genetic polymorphisms in PDE4D gene with IS in Henan Han population.</p><p><b>METHODS</b>A total of 400 patients with IS and 400 matched controls were examined using a case-control design. Two single nucleotide polymorphism (SNPs) (rs918592 and rs2910829) in PDE4D gene were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated to test the association between the genetic factors and IS. Genetic parameter and association studies were carried out with SPSS 16.0.</p><p><b>RESULTS</b>Among the two SNPs tested, the rs918592 was significantly associated with IS (OR: 1.351, 95%CI: 1.110 - 1.645), especially in male patients (OR: 1.427, 95%CI: 1.105 - 1.844). Haplotype analysis showed that A-T was associated with an increased risk of the IS (OR: 2.114, 95%CI: 2.005 - 2.230) while G-T was associated with decreased risk of IS (OR: 0.419, 95%CI: 0.302 - 0.583). Protecting effect of haplotype G-T was also significant in males (OR: 0.264, 95%CI: 0.162 - 0.431).</p><p><b>CONCLUSIONS</b>The present study demonstrated a strong association of rs918592 with IS. Haplotype A-T increased the risk of IS while haplotype G-T had a protective effect in Henan Han population. The association was sex-dependent with male patients showing stronger effect.</p>

Electrophysiological and Behavioral Changes by Phosphodiesterase 4 Inhibitor in a Rat Model of Alcoholic Neuropathy

OBJECTIVE: Alcoholic neuropathy is characterized by allodynia (a discomfort evoked by normally innocuous stimuli), hyperalgesia (an exaggerated pain in response to painful stimuli) and spontaneous burning pain. The aim of the present study is to investigate the effect of rolipram, a phosphodiesterase 4 inhibitor, against alcohol-induced neuropathy in rats. METHODS: Allodynia was induced by administering 35% v/v ethanol (10 g/kg; oral gavage) to Spraue-Dawley rats for 8 weeks. Rolipram and saline (vehicle) were administered intraperitoneally. Mechanical allodynia was measured by using von Frey filaments. Somatosensory evoked potential (SEP) was proposed as complementary measure to assess the integrity of nerve pathway. RESULTS: The ethanol-induced mechanical allodynia began to manifest from 3 week, and then peaked within 1 week. Beginning from 3 week, latency significantly started to increased in control group. In rolipram treated rats, the shorter latency was sustained until 8 weeks (p<0.05). The mechanical allodynia, which began to manifest on the 3 weeks, intraperitoneal injections of rolipram sustained statistical difference until 8 weeks, the final week of the study (p<0.05). CONCLUSION: This study suggests that rolipram might alleviate mechanical allodynia induced by alcohol in rats, which clearly has clinical implication.

The Effect of Phosphodiesterase-4-Specific Inhibitor in the Rat Model of Spinal Nerve Ligation

OBJECTIVE: Peripheral neuropathy is characterized by hyperalgesia, spontaneous burning pain, and allodynia. The purpose of this study was to investigate the effect of rolipram, a phosphodiesterase-4-specific inhibitor, in a segmental spinal nerve ligation model in rats. METHODS: Both the L5 and L6 spinal nerves of the left side of the rats were ligated. Phosphodiesterase-4 inhibitor (rolipram) and saline (vehicle) were administered intraperitoneally. We measured mechanical allodynia using von Frey filaments and a nerve conduction study. RESULTS: The mechanical allodynia, which began to manifest on the first day, peaked within 2 days. Multiple intraperitoneal injections of rolipram ameliorated the mechanical allodynia. Furthermore, an intraperitoneal administration of rolipram improved the development of pain behavior and nerve conduction velocity. CONCLUSION: This study suggests that the phosphodiesterase-4 inhibitor, rolipram, alleviates mechanical allodynia induced by segmental spinal nerve ligation in rats. This finding may have clinical implications.

Phosphodiesterase 4D Gene and Risk of Noncardiogenic Ischemic Stroke in a Korean Population

Recently published studies from different populations provide apparently conflicting evidence on the association between the phosphodiesterase 4D (PDE4D) gene and ischemic stroke. The relationship between a representative PDE4D genotype and ischemic stroke was explored in a case-control study of 205 consecutive Korean patients with noncardiogenic ischemic stroke and 103 healthy controls who were neurologically and radiologically proven to be stroke-free. We selected and genotyped a PDE4D single nucleotide polymorphism (SNP 41, rs152312) as a candidate marker for susceptibility to ischemic stroke because SNP 41 has shown the most significant association with stroke in both a meta-analysis and the original Icelandic study of the PDE4D gene. No significant difference was observed between the cases and controls in the distribution of the PDE4D SNP 41 genotypes. The results from the adjusted conditional logistic regression analysis (adjusted for age, hypertension, diabetes and smoking status) showed no significant association between PDE4D SNP 41 genotypes and an increased risk of noncardiogenic ischemic stroke. The PDE4D gene is not a major risk factor for noncardiogenic ischemic stroke in a Korean population, which supports the recent evidence suggesting that the causative genetic variants of ischemic stroke may differ across populations.

Genetics of ischemic stroke

Stroke is the third leading cause of death and a major cause of disability worldwide. Most cases of ischemic stroke are attributable to hypertension and other risk factors, but in over 20% of cases, the cause is unknown. Recent research has implicated some novel genes in the etiology of ischemic stroke, including genes for soluble epoxide hydrolase [sHE], 5-lipoxygenase activating protein [FLAP] and phosphodiesterase 4D [PDE4D]. Moreover, thrombophilic states such as prothrombin G20210A mutation and factor V Leiden are now known to cause arterial stroke as well as venous thrombosis. Meanwhile, the recent availability of enzyme replacement therapy for Fabry disease and the proven benefits of regular blood transfusion in certain patients with sickle cell disease have greatly altered the outlook of these devastating inherited disorders. Thus, our understanding of the role of genetic factors in stroke raises the prospects for accurate assessment of future stroke risk among susceptible individuals, in whom early preventive measures may be life-saving. Further research into the genetics of stroke will clearly compliment ongoing national and international efforts to reduce the global burden of stroke

Association between mRNA level of Pde4d and Alox5ap and hypertensive stroke as well as hypertension in rats / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To evaluate whether mRNA levels of Pde4d and Alox5ap were associated with hypertensive stroke and hypertension in stroke-prone renovascular hypertensive rats (RHRSP) which could simulate human being's hypertensive cerebral stroke.</p><p><b>METHODS</b>Five groups were established: normotensive group, gradient hypertensive groups I, II and III(with contractive pressure of 140-159 mmHg, 160-179 mmHg and 180-199 mmHg respectively) and spontaneous stroke group. RNA from leukocytes in peripheral blood of each rat underwent real time PCR after reversed.</p><p><b>RESULTS</b>The mRNA levels of Pde4d and Alox5ap of spontaneous stroke group were statistically higher than that of the other groups. Expression of Pde4d of hypertensive group I was a bit higher than that of normotensive group and hypertensive groups II and III; as for Alox5ap, there was no statistical difference between normotensive group and all gradient hypertensive groups.</p><p><b>CONCLUSION</b>Animal experiments come to conclusions that over-expression of Pde4d and Alox5ap are associated with hypertensive stroke but not with hypertension. Therefore, the two genes confer the risk of hypertensive stroke independent of traditional risk factors. It is speculated that over-expression of Pde4d and Alox5ap can motivate onset of hypertensive cerebral stroke by participating in inflammation of arterial walls.</p>

Cyclic nucleotide phosphodiesterase IV expression, activity and targeting in cells of cardiovascular system / 药学学报

Cyclic nucleotide second messages (cAMP and cGMP) play a central role in signal transduction and regulation of physiologic responses. The only way to inactivate them is to degrade them through the action of phosphodiesterases (PDEs). Recent advances show that PDE4, a cAMP specific phosphodiesterase, has specific functions in regulating the activities of the cardiovascular system. PDE4 is expressed in the cells of cardiovascular systems including cardiomyocytes, vascular smooth muscle cells, and vascular endothelial cells. The expression level of PDE4 is shown to be downregulated in the failure hearts, while it is upregulated in hypertrophied hearts. And PDE4 deficiency in mice is associated with a cardiac phenotype comprised of a progressive, age-related cardiomyopathy, accelerated heart failure after myocardial infarction and exercise-induced arrhythmias. Local levels of cAMP regulate the precise opening of the ryanodine receptor complex (RyR2) which releases calcium at the start of a heartbeat. Loss or inhibition of PDE4 activity increases calcium flow through RyR2, and causes leakiness and heart failure in mice. These finding may show us a new target for treating cardiovascular diseases.

Effects of phosphodiesterase 4 inhibitor on cough response in guinea pigs sensitized and challenged with ovalbumin / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>There is currently considerable interest in the potential value of selective inhibitors of cyclic nucleotide phosphodiesterase 4 in the treatment of asthma. However, whether they influence eosinophilic airway inflammation-associated cough remains unclear. The objective of this study was to investigate the effects of selective phosphodiesterase 4 inhibitor SB207499 on cough response and airway inflammation in guinea pigs sensitized and challenged with ovalbumin.</p><p><b>METHODS</b>Forty sensitized guinea pigs were randomly divided into four groups: control (n = 10), challenge (n = 10), SB207499 (n = 10) and aminophylline (n = 10), then challenged with aerosol of 1% ovalbumin or saline. Two hours later, animals were intraperitoneally injected with either saline, 25 mg/kg of SB207499 or aminophylline. At the 24th hour, the injection was repeated with 2.5 mg/kg and 25 mg/kg SB207499 or aminophylline, then cough response to inhaled capsaicin and airway responsiveness to methacholine inducing a 150% of the peak airway pressure to the baseline (PC150) was measured. Finally, total cell number and differentials in bronchoalveolar lavage fluid were analysed.</p><p><b>RESULTS</b>The cough frequency per 3 minutes and PC150 in the challenge group were (22 +/- 4) times/3 minutes and (198 +/- 54) microg/ml, which were significantly different from (6 +/- 2) times/3 minutes and (691 +/- 81) microg/ml in the control group (P < 0.05, respectively). The injection of 25 mg/kg SB207499 significantly inhibited the increased cough response and airway hyperresponsiveness, the cough frequency and PC150 in guinea pigs were (13 +/- 2) times/3 minutes and (680 +/- 81) microg/ml (P < 0.05), which differed significantly from (18 +/- 2) times/3 minutes and (400 +/- 86) microg/ml after the administration of the same dose of aminophylline (P < 0.05). The inhibition of SB207499 on cough response was dose-dependent. Similarly, SB207499 decreased the total cell number and percentage of eosinophils in bronchoalveolar lavage fluid to (2.1 +/- 0.5) x 10(6)/ml and (20 +/- 5)% respectively, which were significantly different from (3.2 +/- 0.5) x 10(6)/ml and (29 +/- 5)% in the aminophylline group (P < 0.05, respectively) or (4.2 +/- 0.7) x 10(6)/ml and (35 +/- 4)% in the challenge group (P < 0.05, respectively).</p><p><b>CONCLUSION</b>Phosphodiesterase 4 inhibitor may be more useful than aminophylline for cough associated with eosinophilic airway inflammation via inhibiting airway inflammation and airway hyperresponsiveness.</p>

The Modulation of IL-12 by Phosphodiesterase IV Inhibitor and Subsequent Changes of Th-1, Th-2 Cytokines in Human Endometrial Tissue / 대한산부인과학회잡지

OBJECTIVE: To assess the capability of phosphodiesterase type IV inhibitor (rolipram) to suppress IL-12 in human decidua and the subsequent changes of Th-2 cytokine (IL-10) and Th-1 cytokine (TNF-alpha). METHODS: Decidual tissues of 10 first-trimester pregnant women and 10 first-trimester pregnant women diagnosed as missed abortion were collected by dilatation and currettage. The decidual tissues were treated with rolipram for 6 hours. Protein and mRNA expression in the tissues were analysed by western blotting, immunohistochemistry and reverse transcription-polymerase chain reaction. RESULTS: Rolipram, in the concentration above 1 microgram/ml, could decrease the expression of IL-12p35 (control: 46.37+/-7.38, rolipram: 24.34+/-8.46) and IL-12p40 mRNA (control: 31.7+/-5.8, rolipram: 14.9+/-4.6) and protein (control: 52.4+/-8.9, rolipram: 40.9+/-12.1). However, the expression of IL-10 and TNF-alpha mRNA and protein did not changed by rolipram. There was no difference in the cytokine expression pattern between the decidual tissues of normal pregnancy and missed abortion. CONCLUSION: Rolipram, the phosphodiesterase type IV inhibitor, could induce the decrease of IL-12 in human decidua. In human decidual tissue, unlike other human tissues, the decrease of IL-12 by rolipram did not modulate other Th-1/Th-2 cytokines. Inability of IL-12 to modulate other Th-1/Th-2 cytokines might be related with unique cytokine network in human decidua rather than its small extent of decrease.