Association between phosphodiesterase 4D gene and ischaemic stroke

Phosphodiesterase 4 inhibition as a novel treatment for stroke

The incidence of stroke ranks third among the leading causes of mortality worldwide. It has the characteristics of high morbidity, high disability rate and high recurrence rate. The current risk associated with stroke surgery is exceedingly high. It may potentially outweigh the benefits and fail to ameliorate the cerebral tissue damage following ischemia. Therefore, pharmacological intervention assumes paramount importance. The use of thrombolytic drugs is most common in the treatment of stroke; however, its efficacy is limited due to its time-sensitive nature and propensity for increased bleeding. Over the past few years, the treatment of stroke has witnessed a surge in interest towards neuroprotective drugs that possess the potential to enhance neurological function. The PDE4D gene has been demonstrated to have a positive correlation with the risk of ischemic stroke. Additionally, the utilization of phosphodiesterase 4 inhibitors can enhance synaptic plasticity within the neural circuitry, regulate cellular metabolism, and prevent secondary brain injury caused by impaired blood flow. These mechanisms collectively facilitate the recovery of functional neurons, thereby serving as potential therapeutic interventions. Therefore, the comprehensive investigation of phosphodiesterase 4 as an innovative pharmacological target for stroke injury provides valuable insights into the development of therapeutic interventions in stroke treatment. This review is intended for, but not limited to, pharmacological researchers, drug target researchers, neurologists, neuromedical researchers, and behavioral scientists.

Single-nucleotide polymorphism rs2910829 in PDE4D is related to stroke susceptibility in Chinese populations: The results of a meta-analysis

Stroke is a debilitating condition that often leads to disability and death. The increasing prevalence of stroke has drawn worldwide attention. Extensive evidence indicates a crucial role of genetic determinants in the occurrence and perpetuation of stroke. An Icelandic study identified a significant correlation of the phosphodiesterase 4D (PDE4D) single-nucleotide polymorphism (SNP) rs2910829 with stroke susceptibility. However, subsequent studies reported in Chinese populations were contradictory. We implemented a meta-analysis to inspect whether SNP rs2910829 is related to stroke susceptibility in Chinese populations and subsequently performed an in silico analysis to predict its potential functions. Finally, we analysed data from 24 studies comprising 7,484 Chinese stroke patients and 7,962 control individuals. Compared with the CC genotype, the TT genotype was associated with increased susceptibility to stroke (pooled odds ratio [OR] 1.28, 95% confidence interval [CI] 1.13-1.46, P < 0.001), whereas the CT genotype was not. Correspondingly, a significant association was detected under the recessive model (TT vs CT + CC: OR 1.30, 95% CI 1.15-1.47, P < 0.001). Similar results were obtained in large artery atherosclerosis (LAA) stroke but not in small vessel stroke. Bioinformatics analysis also revealed that SNP rs2910829 and its linked SNPs might be implicated in transcriptional regulation. This meta-analysis reveals significant relationships between the PDE4D SNP rs2910829 and susceptibility to stroke and subtype-LAA stroke in Chinese individuals, and further investigations are warranted to evaluate this effect.

Phosphodiesterase 4 D (PDE4D) gene polymorphisms and risk of ischemic stroke: A systematic review and meta-analysis

BACKGROUND AND PURPOSE

Studies on the relationship between Phosphodiesterase 4 D (PDE4D) gene polymorphism with the risk of ischemic stroke (IS) have shown discordant results. The present meta-analysis was aimed to clarify the relationship between PDE4D gene polymorphism with the risk of IS by estimating pooled analysis of published epidemiological studies.

METHODS

A comprehensive literature search for all the published articles was performed in various electronic databases, including PubMed, EMbase, Cochrane Library, Trip Database, Worldwide Science, CINAHL, and Google Scholar up to 22nd December 2021. Pooled Odds ratios (ORs) with 95% Confidence Intervals (CIs) under dominant, recessive, and allelic models were calculated. Subgroup analysis based on ethnicity (Caucasian vs. Asian) was performed to examine the reliability of these findings. Sensitivity analysis was also performed to detect the heterogeneity between studies. Finally, Begg's funnel plot was used to assess the potential for publication bias.

RESULTS

In our meta-analysis, we identified a total of 47 case-control studies with 20,644 ischemic stroke (IS) cases and 23,201 control subjects, including 17 studies of Caucasian descent and 30 studies of Asian descent. Our findings suggest that there was a significant relationship between SNP45 gene polymorphism and risk of IS (Recessive model: OR = 2.06, 95% CI 1.31-3.23), SNP83 overall (allelic model: OR = 1.22, 95% CI 1.04-1.42), Asian (allelic model: OR = 1.20, 95% CI 1.05-1.37), and SNP89 Asian (Dominant model: OR = 1.43, 95% CI 1.29-1.59, recessive model: OR = 1.42, 95% CI 1.28-1.58) respectively. However, no significant relationship was found between SNP32, SNP41, SNP26, SNP56, and SNP87 gene polymorphisms and risk of IS.

CONCLUSION

Findings of this meta-analysis conclude that SNP45, SNP83, and SNP89 polymorphism could be capable of increasing stroke susceptibility in Asians but not in the Caucasian population. Genotyping of SNP 45, 83, 89 polymorphisms may be used as a predictor for the occurrence of IS.

Association between PDE4D rs966221 and the Risk of Ischemic Stroke in Regional Chinese Populations

In published research that includes genome-wide association studies and meta-analyses, the phosphodiesterase 4D (PDE4D) rs966221 variant has been identified as a risk factor in ischemic stroke (IS) in the Caucasian population. Several studies have investigated the relationship between rs966221 and IS susceptibility in Chinese populations over the years but have not provided consistently conclusive results. Therefore, our team performed a new meta-analysis of 5973 IS patients and 6204 controls from qualified studies. We observed no significant link between the PDE4D rs966221 variant and IS in any of the regional Chinese populations. Thus, we performed a subgroup analysis by the geographical distribution of China. Notably, significant associations were observed between rs96622 and the susceptibility of IS in the Northeast Chinese populations (p = 1.00 × 10^-4, odds ratio = 1.28, and 95% confidence interval = 1.13-1.44, I² = 0%). However, rs966221 was not found to be correlated with IS risk in the populations of North, Central, South, and East China. Our meta-analysis demonstrated that the PDE4D rs966221 variant is significantly associated with IS risk in some regional Chinese populations.

Association of plaque enhancement on vessel wall MRI and the phosphodiesterase 4D variant with stroke recurrence in patients with symptomatic intracranial atherosclerosis

PURPOSE

Vessel wall MRI (VW-MRI) can be used to evaluate the nature of intracranial atherosclerosis (ICAS) plaque in vivo. Phosphodiesterase 4D (PDE4D) participates in stroke development. This study aims to explore the value of VW-MRI findings and the PDE4D gene variant in predicting stroke recurrence in patients with ICAS.

METHODS

We prospectively recruited 324 symptomatic ICAS patients. VW-MRI was performed to determine luminal and wall changes. PDE4D gene single-nucleotide polymorphisms (SNPs)-namely, SNP32, SNP83, and SNP87-were determined by direct sequencing. The risk factors of stroke recurrence were analyzed using the multivariate Cox proportional hazards model.

RESULTS

Of the 324 subjects, 97 (29.9%) experienced recurrent ischemic stroke during the follow-up period. A total of 254 patients (78.4%) showed plaque enhancement; 87 of these patients experienced stroke recurrence. The CT/CC genotype frequencies of PDE4D83 were significantly higher in participants with recurrent stroke than in patients without stroke recurrence (p = 0.019 and p < 0.001, respectively). However, the PDE4D32 and PDE4D87 variants were not correlated with recurrent stroke. Multivariate analysis showed that plaque enhancement from VW-MRI (HR 4.52, 95% CI 2.35-8.73, p < 0.001) and the PDE4D83 variant (HR 7.43, 95% CI 1.75-31.87, p = 0.005) were independently correlated with stroke recurrence. Kaplan-Meier curves showed significant differences in stroke recurrence rates between the plaque-enhanced group and the non-enhanced group (p < 0.001) and between the PDE4D83 variant carriers and noncarriers (p = 0.002).

CONCLUSION

Plaque enhancement on VW-MRI and the presence of the PDE4D83 variant are associated with ischemic stroke recurrence in subjects with symptomatic ICAS.

PDE4DIP in health and diseases

Cyclic-AMP (cAMP), the first second messenger to be identified, is synthesized, and is universally utilized as a second messenger, and plays important roles in integrity, and function of organs, including heart. Through its coupling with other intracellular messengers, cAMP facilitates excitation-contraction coupling, increases heart rate and conduction velocity. It is degraded by a class of enzymes called cAMP-dependent phosphodiesterase (PDE), with PDE3 and PDE4 being the predominant isoforms in the heart. This highly diverse class of enzymes degrade cAMP and through anchoring proteins generates dynamic microdomains to target specific proteins and control specific cell functions in response to various stimuli. The impaired function of the anchoring protein either by inherited genetic mutations or acquired injuries results in altered intracellular targeting, and blunted responsiveness to stimulating pathways and contributes to pathological cardiac remodeling, cardiac arrhythmias and reduced cell survival. Recent genetic studies provide compelling evidence for an association between the variants in the anchoring protein PDE4DIP and atrial fibrillation, stroke, and heart failure.

Genetics of platelet traits in ischaemic stroke: focus on mean platelet volume and platelet count

Purpose/Aim of the study: The aim of this review is to summarize the role of genetic variants affecting mean platelet volume (MPV) and platelet count (PLT) leading to higher platelet reactivity and in turn to thrombotic events like stroke and cardiovascular diseases.

MATERIALS AND METHODS

A search was conducted in PUBMED, MEDLINE, EMBASE, PROQUEST, Science Direct, Cochrane Library, and Google Scholar related to the studies focussing on genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis that have been employed to identify the genetic variants influencing MPV and PLT.

RESULTS

Antiplatelet agents underscore the crucial role of platelets in the pathogenesis of stroke. Higher platelet reactivity in terms of mean platelet volume (MPV) and platelet count (PLT) contributes significantly to the interindividual variation in platelet reaction at the site of vessel wall injury. Some individuals encounter thrombotic events as platelets get occluded at the site of vessel wall injury whereas others heal the injury without occluding the circulation. Evidence suggests that MPV and PLT have a strong genetic component. High throughput techniques including genome-wide association studies (GWAS), whole exome sequencing (WES), whole genome sequencing (WGS), phenome-wide association studies (PheWAS) and multi-omic analysis have identified different genetic variants influencing MPV and PLT.

CONCLUSIONS

Identification of complex genetic cross talks affecting PLT and MPV might help to develop novel treatment strategies in treating neurovascular diseases like stroke.

Association between PDE4D rs966221 polymorphism and risk of ischemic stroke: a systematic review and meta-analysis

PDE4D polymorphism (SNP83/rs966221) was reported to be associated with the susceptibility to ischemic stroke (IS), however, the results were inconclusive. An electronic search of Embase, PubMed, CNKI and Wan Fang Date was performed to identify relevant studies published throughout April 2017. A total of 26 studies were enrolled in the analysis. No significant association between the rs9662221 polymorphism and IS was observed in the overall analysis. Nevertheless, in the subgroup analysis, our results showed a significant association between the SNP83 polymorphism and IS in CC+ CT vs. TT (OR = 1.19, 95% CI: 1.02-1.38), CT vs.TT (OR = 1.14, 95% CI: 1.01-1.29) and C vs. T (OR = 1.25, 95% CI: 1.06-1.48) in Asian population. But we did not found any association in CC vs. CT + TT (OR = 1.2, 95% CI: 0.9-1.61) and CC vs. TT (OR = 1.26, 95% CI: 0.91-1.75) in the Asian populations. Meantime, no significant correlations were observed under the five genetic model in Caucasian population (p > 0.05). In conclusion, our meta-analysis demonstrated that the SNP83 polymorphism in the PDE4D gene might contribute to IS susceptibility especially in Asian populations. Whereas the relationship of the polymorphism to the disease in Caucasian population was still in controversial. In future, additional well designed studies with larger sample sizes are still required to further elucidate this association.

Relationship of phosphodiesterase 4D (PDE4D) gene polymorphisms with risk of ischemic stroke: a hospital based case-control study

BACKGROUND

Stroke remains a leading cause of death and disability worldwide. Ischemic stroke (IS) accounts for around 80-85% of total stroke and is a complex polygenic multi-factorial disorder which is affected by a complex combination of vascular, environmental, and genetic factors.

OBJECTIVE

The study was conducted with an aim to examine the relationship of single nucleotide polymorphisms (SNPs) of PDE4D (T83C, C87T, and C45T) gene with increasing risk of IS in patients in North Indian population.

METHODS

In this hospital-based case-control study, 250 IS subjects and 250 age-and sex-matched control subjects were enrolled from the Neurosciences Centre, A.I.I.M.S., New Delhi, India. Deoxyribonucleic acids (DNAs) were extracted using the conventional Phenol-Chloroform isolation method. Different genotypes were determined by Polymerase chain reaction- Restriction fragment length polymorphism method. Odds ratio (OR) and 95% Confidence Interval (CI) of relationship of polymorphisms with risk of IS were calculated by conditional multivariable regression analysis.

RESULTS

High blood pressure, low socioeconomic status, dyslipidemia, diabetes, and family history of stroke were observed to be statistically significant risk factors for IS. Multivariable adjusted analysis demonstrated a statistically significant relationship between SNP 83 of PDE4D gene polymorphism and increasing odds of IS under the dominant model of inheritance (OR, 1.59; 95% CI, 1.02 to 2.50; p value = 0.04) after adjustment of potential confounding variables. Stratified analysis on the basis of TOAST classification demonstrated a statistically significant association for increasing 2.73 times odds for developing large vessel disease stroke as compared to controls (OR, 2.73; 95% CI, 1.16 to 0.02; p value = 0.02). We did not find any significant association of SNPs (C87T and C45T) of the PDE4D gene with the risk of IS.

CONCLUSION

SNP 83 of PDE4D gene may increase the risk for developing IS whereas SNP 87 and SNP45 of PDE4D may not be associated with the risk of IS in the North Indian population. Prospective cohort studies are required to corroborate these findings.

Impact of the PDE4D gene polymorphism and additional SNP-SNP and gene-smoking interaction on ischemic stroke risk in Chinese Han population

AIMS

To investigate the association between phosphodiesterase 4D gene (PDE4D) gene single nucleotide polymorphisms (SNPs) and ischemic stroke (IS) risk, and impact of additional SNP- SNP and gene- smoking interaction on IS risk in Chinese population.

METHODS

A total of 1228 subjects (666 males, 562 females) were selected, including 610 IS patients and 618 control subjects. Logistic regression model was used to examine the association between SNPs in PDE4D gene and IS risk. Generalized multifactor dimensionality reduction (GMDR) was employed to analyze the SNP- SNP and gene- smoking interaction.

RESULTS

IS risks were significantly higher in carriers of A allele of rs12188950 polymorphism than those with GG genotype (GA + AA vs. GG), adjusted OR (95%CI) = 1.61 (1.26-2.19), and also significantly higher in carriers of T allele of rs966221 polymorphism than those with CC (CT + TT vs. CC), adjusted OR (95%CI) = 1.82 (1.39-2.23). We found that there was a significant SNP- SNP interaction between rs966221 and rs12188950. Subjects with CT or TT of rs966221 and GA or AA of rs12188950 genotype have the highest IS risk, compared to subjects with CC of rs966221 and GG of rs12188950 genotype, OR (95%CI) was 3.52 (2.68-4.69). We also found a significant gene-environment interaction between rs966221 and smoking. Smokers with CT or TT of rs966221 genotype have the highest IS risk, compared to never smokers with CC of rs966221 genotype, OR (95%CI) was 3.97 (2.25-5.71).

CONCLUSIONS

Our results support an important association of rs966221 and rs12188950 minor allele and its interaction with increased risk of IS risk, and additional interaction between rs966221 and smoking.

The SG13S114 polymorphism of the ALOX5AP gene is associated with ischemic stroke in Europeans: a meta-analysis of 8062 subjects

The association between ALOX5AP SG13S114 polymorphism and ischemic stroke (IS) susceptibility has extensively been investigated, especially in white populations; however, the results were inconclusive. Here, we perform a meta-analysis to clarify the effect of SG13S114 variant on the IS risk in Europeans. The Web of Science, PubMed, EMBASE, and Medline were searched up to August 1st, 2016. Data were extracted and the odd ratios (ORs) and 95% confidence intervals (CIs) were calculated by a fixed-effects or random-effects model. In total, 8 case control studies involved 8062 subjects were finally included in this meta-analysis. We observed a significantly decreased IS risk in persons carrying an A allele at the SG13S114 polymorphism compared with those with a T allele (A vs T, OR = 0.856, 95% CI = 0.797-0.919, p < 0.001). In addition, the results of sensitivity and cumulative meta-analysis indicated the robustness of our results. In addition, the publication bias was not detected using the funnel plot and Egger's tests. In summary, the present meta-analysis suggested that the A allele at the ALOX5AP SG13S114 polymorphism is a protective factor for the IS in the Europeans. In addition, further studies with large sample size are needed to validate the association, as well as in other ethnic groups.

Genetic Understanding of Stroke Treatment: Potential Role for Phosphodiesterase Inhibitors

Phosphodiesterase (PDE) gene family is a large family having at least 21 genes and multiple versions (isoforms) of the phosphodiesterase enzymes. These enzymes catalyze the inactivation of intracellular mediators of signal transduction such as cAMP and cGMP and therefore, play a pivotal role in various cellular functions. PDE inhibitors (PDEI) are drugs that block one or more of the five subtypes of the PDE family and thereby prevent inactivation of the intracellular cAMP and cGMP by the respective PDE-subtypes. The first clinical use of PDEI was reported almost three decades ago. Studies later found the ability of these compounds to increase the levels of ubiquitous secondary messenger molecules that can cause changes in vascular tone, cardiac function and other cellular events and thus these findings paved the way for their use in various medical emergencies. PDEs are found to be distributed in many tissues including brain. Therefore, new therapeutic agents in the form of PDEI are being explored in neurodegenerative diseases including stroke. Although studies have revealed their use in cerebral infarction prevention, their full-fledged application in times of neurological emergency or stroke in specific has been very limited so far. Nevertheless, recent investigations suggest PDE4 and PDE5 inhibitors to play a vital role in mitigating stroke symptoms by modulating signaling mechanisms in PDE pathway. Further, extensive research in terms of their pharmacological properties like dosing, drug specific activities, use of simultaneous medications, ancillary properties of these compounds and studies on adverse drug reactions needs to be carried out to set them as standard drugs of use in stroke.

No Association Between Single-Nucleotide Polymorphism 56 (SNP56) in Phosphodiesterase 4D (PDE4D) Gene and Susceptibility to Ischemic Stroke: A Meta-Analysis of 15 Studies

Background

Recent studies demonstrated that polymorphisms in the PDE4D gene were associated with several processes involved in the occurrence of ischemic stroke (IS). The association between specific PDE4D single-nucleotide polymorphism 56 (SNP56) and IS risk was initially identified via genome-wide association studies (GWAS), although the GWAS in different populations produced inconclusive results. Thus, we performed a meta-analysis to better explain the association between PDE4D SNP56 and IS risk.

Material/Methods

A literature search was conducted using PubMed, Embase, and Web of Science up to June 1, 2015. A fixed-effects or random-effects model was used to calculate the pooled odds ratios (ORs) based on the results from the heterogeneity tests.

Results

Finally, we performed a meta-analysis of 15 studies, involving 8731 IS patients and 10,756 controls. The results showed nonsignificant association between PDE4D SNP56 and IS risk (T vs. A: OR=1.01, 95%CI=0.88–1.15, P=0.90). Similarly, in the subgroup analysis by ethnicity, no significant association was observed in Asian (T vs. A: OR=1.08, 95%CI=0.80–1.44, P=0.62) or European (T vs. A: OR=0.96, 95%CI=0.86–1.08, P=0.54) population. Moreover, funnel plots and Egger regression testing showed no evidence of publication bias.

Conclusions

In summary, current evidence suggested that PDE4D SNP56 might not be associated with an increased susceptibility to IS. However, this conclusion needs further validation by well-designed studies with large sample sizes.

MEK Inhibitors Reverse cAMP-Mediated Anxiety in Zebrafish

Altered phosphodiesterase (PDE)-cyclic AMP (cAMP) activity is frequently associated with anxiety disorders, but current therapies act by reducing neuronal excitability rather than targeting PDE-cAMP-mediated signaling pathways. Here, we report the novel repositioning of anti-cancer MEK inhibitors as anxiolytics in a zebrafish model of anxiety-like behaviors. PDE inhibitors or activators of adenylate cyclase cause behaviors consistent with anxiety in larvae and adult zebrafish. Small-molecule screening identifies MEK inhibitors as potent suppressors of cAMP anxiety behaviors in both larvae and adult zebrafish, while causing no anxiolytic behavioral effects on their own. The mechanism underlying cAMP-induced anxiety is via crosstalk to activation of the RAS-MAPK signaling pathway. We propose that targeting crosstalk signaling pathways can be an effective strategy for mental health disorders, and advance the repositioning of MEK inhibitors as behavior stabilizers in the context of increased cAMP.

Rare and Coding Region Genetic Variants Associated With Risk of Ischemic Stroke: The NHLBI Exome Sequence Project

IMPORTANCE

Stroke is the second leading cause of death and the third leading cause of years of life lost. Genetic factors contribute to stroke prevalence, and candidate gene and genome-wide association studies (GWAS) have identified variants associated with ischemic stroke risk. These variants often have small effects without obvious biological significance. Exome sequencing may discover predicted protein-altering variants with a potentially large effect on ischemic stroke risk.

OBJECTIVE

To investigate the contribution of rare and common genetic variants to ischemic stroke risk by targeting the protein-coding regions of the human genome.

DESIGN, SETTING, AND PARTICIPANTS

The National Heart, Lung, and Blood Institute (NHLBI) Exome Sequencing Project (ESP) analyzed approximately 6000 participants from numerous cohorts of European and African ancestry. For discovery, 365 cases of ischemic stroke (small-vessel and large-vessel subtypes) and 809 European ancestry controls were sequenced; for replication, 47 affected sibpairs concordant for stroke subtype and an African American case-control series were sequenced, with 1672 cases and 4509 European ancestry controls genotyped. The ESP's exome sequencing and genotyping started on January 1, 2010, and continued through June 30, 2012. Analyses were conducted on the full data set between July 12, 2012, and July 13, 2013.

MAIN OUTCOMES AND MEASURES

Discovery of new variants or genes contributing to ischemic stroke risk and subtype (primary analysis) and determination of support for protein-coding variants contributing to risk in previously published candidate genes (secondary analysis).

RESULTS

We identified 2 novel genes associated with an increased risk of ischemic stroke: a protein-coding variant in PDE4DIP (rs1778155; odds ratio, 2.15; P = 2.63 × 10(-8)) with an intracellular signal transduction mechanism and in ACOT4 (rs35724886; odds ratio, 2.04; P = 1.24 × 10(-7)) with a fatty acid metabolism; confirmation of PDE4DIP was observed in affected sibpair families with large-vessel stroke subtype and in African Americans. Replication of protein-coding variants in candidate genes was observed for 2 previously reported GWAS associations: ZFHX3 (cardioembolic stroke) and ABCA1 (large-vessel stroke).

CONCLUSIONS AND RELEVANCE

Exome sequencing discovered 2 novel genes and mechanisms, PDE4DIP and ACOT4, associated with increased risk for ischemic stroke. In addition, ZFHX3 and ABCA1 were discovered to have protein-coding variants associated with ischemic stroke. These results suggest that genetic variation in novel pathways contributes to ischemic stroke risk and serves as a target for prediction, prevention, and therapy.

Association between phosphodiesterase 4D (PDE4D) SNP 87 and ischemic stroke: a meta-analysis

BACKGROUND AND PURPOSE

Data on the association between PDE4D SNP 87 and the risk of ischemic stroke are contentious and debatable. The present meta-analysis was undertaken to systematically summarize the possible association.

METHODS

Based on comprehensive search of PubMed, Embase, and CNKI databases, we identified 18 eligible articles examining the relationship between PDE4D SNP 87 and ischemic stroke risk. We evaluated the strength of relationship using odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

In the overall analysis, PDE4D SNP 87 was not found to have effects on the risk of ischemic stroke. The null association persisted in the subgroup analyses according to ethnicity and sample size.

CONCLUSIONS

Our meta-analysis suggests that PDE4D SNP 87 may not represent an independent risk factor for ischemic stroke development.

Phosphodiesterase 4D single-nucleotide polymorphism 83 and cognitive dysfunction in carotid endarterectomy patients

BACKGROUND

Phosphodiesterase 4D (PDE4D), through the regulation of cyclic AMP, modulates inflammation and other processes that affect atherosclerosis and stroke. A PDE4D polymorphism, single-nucleotide polymorphism (SNP) 83 (rs966221), is associated with ischemic stroke. The association of SNP 83 with postoperative cognitive dysfunction has never been investigated.

OBJECTIVE

To determine whether SNP 83 is associated with cognitive dysfunction 1 day and 1 month following carotid endarterectomy (CEA).

METHODS

Three hundred fourteen patients with high-grade carotid stenosis scheduled for CEA consented to participate in this single-center cohort study of cognitive dysfunction.

RESULTS

Patients with the C/C genotype of SNP 83 exhibited significantly more cognitive dysfunction at 1 day (29.7%) than the C/T (15.8%, P = .008) and T/T (12.7%, P = .01) genotypes. In a multivariate logistic regression model, C/T and T/T genotypes were both associated with significantly decreased odds of cognitive dysfunction compared with the C/C genotype (odds ratio, 0.45 [0.24-0.83], P = .01 and odds ratio, 0.33 [0.12-0.77], P = .02). There were no significant associations at 1 month.

CONCLUSION

The C/C genotype of SNP 83 is significantly associated with the highest incidence of cognitive dysfunction 1 day following CEA in comparison with the C/T and T/T genotypes. This PDE4D genotype may lead to accelerated cyclic AMP degradation and subsequently elevated inflammation 1 day after CEA. These observations, in conjunction with previous studies, suggest that elevated inflammatory states may be partially responsible for the development of cognitive dysfunction after CEA, but more investigation is required.

Association of nNOS gene polymorphism with ischemic stroke in Han Chinese of North China

Nitric oxide (NO) is an important messenger molecule and effector molecule. This study aimed to investigate the relation of neuronal nitric oxide synthase (nNOS) gene polymorphism with ischemic stroke in Han Chinese of North China. This was a case-control study. A total of 413 patients with ischemic stroke were recruited from Han Chinese of North China. There were 201 males and 212 females. In addition, 477 healthy subjects served as controls including 224 males and 253 females. Multiplex SNaPshot was employed to detect nNOS gene polymorphism (rs2293050, rs2139733, rs7308402, and rs1483757). Results showed that the rs1483757, rs2139733, and rs2293050 genotypes and allele frequencies were comparable between patients and controls. However, ischemic stroke patients had significantly reduced AG genotype and A allele frequency when compared with controls (P = 0.037, P = 0.041). After adjusting confounding factors (gender, age, smoking, history of drinking, hypertension, and diabetes), AG genotype and A allele were still related to ischemic stroke (OR = 0.572, 95% CI: 0.335–0.978, P = 0.041; OR = 0.611, 95% C: 0.378–0.985, and P = 0.041) and both were found to be protective factors. Our results showed that rs7308402 gene polymorphism of nNOS is related to ischemic stroke in Han Chinese of North China.

Genetic polymorphism in PDE4D gene and risk of ischemic stroke in Chinese population: a meta-analysis

Background

Stroke is the second most common cause of death and major cause of disability worldwide. The SNP 83 in PDE4D gene has been suggested as a risk factor in ischemic stroke, but direct evidence from genetic association studies remains inconclusive even in Chinese population.

Methods

Meta-analysis of case-control studies on the relationship between SNP 83 in PDE4D gene and susceptibility to ischemic stroke in Chinese population published domestically and abroad from January 2003 to September 2012.

Results

9 case-control studies were selected. Meta-analysis results showed that the significant association between SNP 83 and ischemic stroke was found under the dominant model (OR = 1.34, 95% CI: 1.20–1.49) and recessive model (OR = 1.45, 95% CI: 1.19–1.76) in Chinese population. In subgroup meta-analysis, SNP 83 and atherothrombotic stroke, rather than lacunar stroke, showed the significant association under the dominant model (OR = 1.69, 95% CI: 1.41–2.01) and recessive model (OR = 1.47, 95% CI: 1.04–2.06).

Conclusions

The results suggest that SNP 83 in PDE4D gene is significantly associated with susceptibility to ischemic stroke in Chinese population.

Association of inflammatory response gene polymorphism with atherothrombotic stroke in Northern Han Chinese

Atherosclerosis is an important pathophysiological basis of atherothrombotic stroke (ATS), and inflammation plays a significant role in atherosclerosis formation. In this study, single-nucleotide polymorphisms (SNPs) in three key inflammation-related genes, 5-lipoxygenase activating protein (ALOX5AP), phosphodiesterase 4D (PDE4D), and interleukin-1α (IL-1α), were investigated to determine their association with ATS in Northern Han Chinese. Six-hundred and eighty-two ATS patients and 598 unrelated controls were recruited. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism and matrix-assisted laser desorption ionization time-of-flight mass spectrometry primer extension. The genotype and allele frequencies of each SNP were statistically analyzed. Risk of ATS was found for the ALOX5AP SG13S114A/T AA genotype (P = 0.040) and A allele (P = 0.033), PDE4D SNP83C/T TT genotype (P = 0.010) and T allele (P = 0.008) and SNP219A/G GG genotype (P = 0.025) and G allele (P = 0.022), and the IL-1α-889C/T T allele (P = 0.035). The differences still remained significant after adjustment. The ALOX5AP HapA haplotype was not correlated with ATS (P = 0.834), but GCGA represented an at-risk haplotype (P = 0.008). Furthermore, the PDE4D AA haplotype at SNP219-220 might be an at-risk haplotype (P = 0.013), while GA might be a protective haplotype (P = 0.005). The ALOX5AP (SG13S114A/T), PDE4D (SNP83C/T, 219A/G), and IL-1α (-889C/T) SNPs were associated with an increased risk of ATS in Northern Han Chinese.

Association of SNP41, SNP56 and a novel SNP in PDE4D gene with stroke and its subtypes

An association between phosphodiesterase 4D (PDE4D) gene and risk of stroke has been suggested by deCODE group in an Icelandic population. In the present case-control study we investigated the association of SNP41 (rs12153798) and SNP56 (rs702553) with ischemic stroke and stroke subtypes. Five hundred and sixteen ischemic stroke patients and 513 healthy age and sex matched controls were included in the study. The genotypes were determined by subjecting the PCR products to sequencing. Both the SNPs 56 and 41 associated significantly with stroke [adjusted OR=1.97; 95% CI (1.262-3.082); p=0.003: adjusted OR=5.42; 95% CI (3.45-8.5); p<0.001 respectively]. In addition to this, a novel SNP at position 59736747 T>G was found while sequencing the PCR products including SNP56. This novel SNP was found in patients as well as controls but did not show a significant association with the disease. We found significant association of SNPs 56 and 41 with large artery atherosclerosis, lacunar and cardioembolic stroke. In conclusion PDE4D gene plays a key part in the pathogenesis of ischemic stroke in the South Indian population from Andhra Pradesh.

A large-sample assessment of possible association between ischaemic stroke and rs12188950 in the PDE4D gene

Previous reports have shown ambiguous findings regarding the possible associations between ischaemic stroke (IS) and single nucleotide polymorphisms (SNPs) in the phosphodiesterase 4D (PDE4D) gene region. The SNP rs12188950 (or SNP45) has often been studied in this context. We performed a multi-centre study involving a large sample of 2599 IS patients and 2093 control subjects from the south and west regions of Sweden to replicate previous studies regarding IS risk and rs12188950. Subjects from Lund Stroke Register (LSR), Malmö Diet and Cancer Study (MDC) and Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS) were enroled. Subgroups of participants with hypertension and participants <55 years of age, as well as the TOAST subgroups large vessel disease, small vessel disease and cardioembolism, were also assessed. Univariate odds ratios (ORs) and ORs controlling for hypertension, diabetes and current smoking were calculated. We additionally performed a meta-analysis including 10,500 patients and 10,102 control subjects from 17 publications (including the present study). When assessing pooled data from LSR, MDC and SAHLSIS we obtained no association between IS and rs12188950 for all participants (OR=0.93; 95% confidence interval (CI): 0.83-1.05). Significant associations were not found for hypertensive participants or participants with age <55, or when separately evaluating patients from the three different TOAST subgroups. The meta-analysis showed no significant overall estimate (OR=0.96; 95% CI: 0.89-1.04) with significant heterogeneity for random effect (P=0.042). No effect from rs12188950 on IS was found from either our pooled multi-centre data or the performed meta-analysis. We did not find any association between the examined subgroups and rs12188950 either.

Association of the phosphodiesterase 4D (PDE4D) gene and cardioembolic stroke in an Australian cohort

BACKGROUND

Large-scale epidemiological studies support an important role for susceptibility genes in the pathogenesis of ischemic stroke, with phosphodiesterase 4D identified as the first gene predisposing to ischemic stroke. Several single nucleotide polymorphisms within the phosphodiesterase 4D gene have been implicated in the pathogenesis of stroke. Aim Undertake a multivariate analysis of six single nucleotide polymorphisms within the phosphodiesterase 4D gene in a previously defined Australian stroke cohort, to determine whether these single nucleotide polymorphisms have an association with ischemic stroke.

METHODS

This case-control study was performed using an existing genetic database of 180 ischemic stroke patients and 301 community controls, evaluated previously for cerebrovascular risk factors (hypertension, hypercholesterolemia, diabetes, paroxysmal atrial fibrillation, smoking and history of stroke in a first-degree relative). Based on previously reported associations with large vessel disease, ischemic stroke, cardioembolic stroke or a mixture of these, six single nucleotide polymorphisms in the phosphodiesterase 4D gene were selected for study, these being single nucleotide polymorphisms 13, 19, rs152312, 45, 83 and 87, based on previously utilized DeCODE nomenclature. Single nucleotide polymorphisms were genotyped using a sequence-specific polymerase chain reaction method and gel electrophoresis. Logistic regression was undertaken to determine the relevance of each polymorphism to stroke. Further analysis was undertaken to determine the risk of stroke following stratification for stroke sub-type and etiology.

RESULTS

Significant odds ratios were found to be associated with cardioembolic strokes in two single nucleotide polymorphisms: rs152312 and SNP 45 (P < 0 · 05).

CONCLUSIONS

Our findings demonstrated an association between cardioembolic stroke and phosphodiesterase 4D single nucleotide polymorphisms rs152312 and 45. No significant association was found for the other four single nucleotide polymorphisms investigated within the phosphodiesterase 4D gene. We propose that the results from this Australian population support the concept that a large prospective international study is required to investigate the role of phosphodiesterase 4D in the cardiogenic cause of ischemic stroke.

Meta-analysis of homogeneous subgroups reveals association between PDE4D gene variants and ischemic stroke

BACKGROUND

An Icelandic study showed a significant positive association between phosphodiesterase 4D (PDE4D) gene variants and stroke. However, subsequent studies reported conflicting results, possibly due to small sample sizes and the heterogeneity of the studies.

METHOD

We performed a meta-analysis on 6 SNPs of the PDE4D gene to investigate the association between this gene and ischemic stroke by integrating the results of previous studies, comprising 11,834 cases and 15,233 controls. A pooled genotypic odds ratio (OR) for each SNP was determined under 3 genetic models (i.e. dominant, recessive, and codominant) using both fixed- and random-effects models with consideration for heterogeneity and publication bias across studies.

RESULTS

Among the SNPs included in this study, SNP56 (rs702553) showed the most significant association with ischemic stroke in a meta-analysis comprised of 7 homogenous studies. The overall OR of the TT genotype compared to the AA genotype was 1.29 (95% CI 1.03-1.61; p = 0.022). For SNP83 (rs966221), a protective effect of the ancestral allele T was observed only in Asian populations (ORTT 0.79, 95% CI 0.69-0.90; p = 0.0005). This meta-analysis revealed a significant association of PDE4D gene variants with the risk of ischemic stroke, and further investigations are warranted to evaluate possible ethnic-specific effects.

Lentiviral-Mediated shRNA Silencing of PDE4D Gene Inhibits Platelet-Derived Growth Factor-Induced Proliferation and Migration of Rat Aortic Smooth Muscle Cells

Phosphodiesterase 4D (PDE4D) is a member of the large superfamily of phosphodiesterases. PDE4D polymorphisms have been found to associate with ischemic stroke. Proliferation and migration of vascular smooth muscle cells (VSMCs) play a critical role in the pathogenesis of atherosclerosis. In this study, infection of VSMCs with lentivrius particles carrying shRNA direct against PDE4D significantly inhibited platelet-derived growth factor-induced VSMC proliferation and migration, and the inhibitory effects were not associated with global intracellular cAMP level. Our results implicate that PDE4D has an important role in VSMC proliferation and migration which may explain its genetic susceptibility to ischemic stroke.

Bio-Repository of DNA in stroke (BRAINS): a study protocol

Background

Stroke is one of the commonest causes of mortality in the world and anticipated to be an increasing burden to the developing world. Stroke has a genetic basis and identifying those genes may not only help us define the mechanisms that cause stroke but also identify novel therapeutic targets. However, large scale highly phenotyped DNA repositories are required in order for this to be achieved.

Methods

The proposed Bio-Repository of DNA in Stroke (BRAINS) will recruit all subtypes of stroke as well as controls from two different continents, Europe and Asia. Subjects recruited from the UK will include stroke patients of European ancestry as well as British South Asians. Stroke subjects from South Asia will be recruited from India and Sri Lanka. South Asian cases will also have control subjects recruited.

Discussion

We describe a study protocol to establish a large and highly characterized stroke biobank in those of European and South Asian descent. With different ethnic populations being recruited, BRAINS has the ability to compare and contrast genetic risk factors between those of differing ancestral descent as well as those who migrate into different environments.

Concerted regulation of cGMP and cAMP phosphodiesterases in early cardiac hypertrophy induced by angiotensin II

Left ventricular hypertrophy leads to heart failure and represents a high risk leading to premature death. Cyclic nucleotides (cAMP and cGMP) play a major role in heart contractility and cyclic nucleotide phosphodiesterases (PDEs) are involved in different stages of advanced cardiac diseases. We have investigated their contributions in the very initial stages of left ventricular hypertrophy development. Wistar male rats were treated over two weeks by chronic infusion of angiotensin II using osmotic mini-pumps. Left cardiac ventricles were used as total homogenates for analysis. PDE1 to PDE5 specific activities and protein and mRNA expressions were explored.

Rats developed arterial hypertension associated with a slight cardiac hypertrophy (+24%). cAMP-PDE4 activity was specifically increased while cGMP-PDE activities were broadly increased (+130% for PDE1; +76% for PDE2; +113% for PDE5) and associated with increased expressions for PDE1A, PDE1C and PDE5A. The cGMP-PDE1 activation by Ca²⁺/CaM was reduced. BNP expression was increased by 3.5-fold, while NOX2 expression was reduced by 66% and AMP kinase activation was increased by 64%. In early cardiac hypertrophy induced by angiotensin II, all specific PDE activities in left cardiac ventricles were increased, favoring an increase in cGMP hydrolysis by PDE1, PDE2 and PDE5. Increased cAMP hydrolysis was related to PDE4. We observed the establishment of two cardioprotective mechanisms and we suggest that these mechanisms could lead to increase intracellular cGMP: i) increased expression of BNP could increase “particulate” cGMP pool; ii) increased activation of AMPK, subsequent to increase in PDE4 activity and 5′AMP generation, could elevate “soluble” cGMP pool by enhancing NO bioavailability through NOX2 down-regulation. More studies are needed to support these assumptions. Nevertheless, our results suggest a potential link between PDE4 and AMPK/NOX2 and they point out that cGMP-PDEs, especially PDE1 and PDE2, may be interesting therapeutic targets in preventing cardiac hypertrophy.

Sex-differential genetic effect of phosphodiesterase 4D (PDE4D) on carotid atherosclerosis

BACKGROUND

The phosphodiesterase 4D (PDE4D) gene was reported as a susceptibility gene to stroke. The genetic effect might be attributed to its role in modulating the atherogenic process in the carotid arteries. Using carotid intima-media thickness (IMT) and plaque index as phenotypes, the present study sought to determine the influence of this gene on subclinical atherosclerosis.

METHODS

Carotid ultrasonography was performed on 1013 stroke-free subjects who participated in the health screening programs (age 52.6 +/- 12.2; 47.6% men). Genotype distribution was compared among the high-risk (plaque index > or = 4), low-risk (index = 1-3), and reference (index = 0) groups. We analyzed continuous IMT data and further dichotomized IMT data using mean plus one standard deviation as the cutoff level. Because the plaque prevalence and IMT values displayed a notable difference between men and women, we carried out sex-specific analyses in addition to analyzing the overall data. Rs702553 at the PDE4D gene was selected because it conferred a risk for young stroke in our previous report. Previous young stroke data (190 cases and 211 controls) with an additional 532 control subjects without ultrasonic data were shown as a cross-validation for the genetic effect.

RESULTS

In the overall analyses, the rare homozygote of rs702553 led to an OR of 3.1 (p = 0.034) for a plaque index > or = 4. When subjects were stratified by sex, the genetic effect was only evident in men but not in women. Comparing male subjects with plaque index > or = 4 and those with plaque index = 0, the TT genotype was over-represented (27.6% vs. 13.4%, p = 0.008). For dichotomized IMT data in men, the TT genotype had an OR of 2.1 (p = 0.032) for a thicker IMT at the common carotid artery compared with the (AA + AT) genotypes. In women, neither IMT nor plaque index was associated with rs702553. Similarly, SNP rs702553 was only significant in young stroke men (OR = 1.8, p = 0.025) but not in women (p = 0.27).

CONCLUSIONS

The present study demonstrates a sex-differential effect of PDE4D on IMT, plaque index and stroke, which highlights its influence on various aspects of atherogenesis.

CYP4F2 gene V433M polymorphism is associated with ischemic stroke in the male Northern Chinese Han population

BACKGROUND

CYP4F2 is a member of the cytochrome P450 enzymes and is responsible for metabolizing arachidonic acid to 20-hydroxyeicosatetraenoic acid (20-HETE); 20-HETE plays a role in the regulation of vascular tone in the cerebral, coronary, and renal circulation. The present study aimed to evaluate whether or not the CYP4F2 gene polymorphism V433M (rs2108622) is involved in ischemic stroke in the Northern Chinese Han population.

METHODS

In a case-control study, the participants included 302 (193 males and 109 females) patients with ischemic stroke and 350 (212 males and 138 females) healthy subjects. The V433M polymorphism of the CYP4F2 gene was analyzed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) with the restriction enzyme PvuII.

RESULTS

The frequencies of the GG genotype and the G allele were higher in participants with ischemic stroke than in the control group (P=0.018). Multiple logistic regression analysis revealed the significance of the rs2108622 in males after adjustment for confounding factors. No difference was found in all participants and females.

CONCLUSION

The GG genotype and G allele were associated with ischemic stroke in the male Northern Chinese Han population.

Association of PDE4D and IL-1 gene polymorphism with ischemic stroke in a Han Chinese population

BACKGROUND

The single-nucleotide polymorphisms (SNPs) of the phosphodiesterase 4D (PDE4D) and interleukin-1 (IL-1) genes are associated with increased risk for the development of ischemic stroke (IS) in whites. However, little is known about whether this association could also occur in Han Chinese.

METHOD

A total of 371 patients with IS and unrelated healthy controls were recruited and the SNPs of the PDE4D (83T/C), (87T/C), IL-1 (-889C/T) and IL-1 (-511C/T) were characterized, respectively, by polymerase chain reactions-restriction fragment length polymorphism (PCR-RFLP). The genotype and allele frequencies of these SNPs in this population were statistically analyzed.

RESULTS

The genotype and allele frequencies of the PDE4D (87T/C) and IL-1 (-511C/T) were similar between IS patients and controls. In contrast, the frequencies of CC genotype and C allele of the PDE4D (83T/C) and the T allele frequency of IL-1 (-889C/T) in IS patients were significantly higher than that in healthy controls (p=0.001, p=0.003 and p=0.02, respectively), independent of the conventional risk factors. The values of odds ratio (OR) reached at OR=1.603; 95%CI=1.032-2.489; p=0.036 for the CC genotype of the PDE4D (83T/C) and OR=1.913; 95%CI=1.621-2.375; p=0.034 for the TT genotype of the IL-1 (-889C/T), respectively.

CONCLUSIONS

the SNPs of the PDE4D (83T/C) and IL-1 (-889C/T) were associated with increased risk for the development of IS in Northern Han Chinese.

The genetics of ischaemic stroke

In this review, we discuss the genetic factors in both the aetiology and treatment of ischaemic stroke. We discuss candidate gene association studies, family linkage studies and the more recent whole genome association studies and whole genome expression studies. We also briefly discuss genetic testing for stroke risk and genetic analysis of treatment complications.

Association between the PDE4D gene and ischaemic stroke in the Chinese Han population

Recent findings suggests that PDE4D (gene encoding phosphodiesterase 4D) is a stroke-related gene in the Icelandic population, but it is still very controversial as to whether it is a susceptible gene for stroke in other populations. In the present study, we attempted to explore the role of the gene in the pathogenesis of stroke in the Chinese Han population of eastern China. A total of 649 ischaemic stroke patients and 761 unrelated control individuals with no history of stroke or transient ischaemic attack were examined in a case-control study. Four SNPs (single nucleotide polymorphisms) rs152312 (C/T), SNP56 (A/T), SNP83 (C/T) and SNP87 (C/T) with a minor allele frequency over 5% were genotyped and the corresponding haplotypes were constructed. In an analysis of the combined cardiogenic and carotid stroke group, both the allele (P=0.0060) and genotype (P=0.0160) frequencies between cases and controls at SNP83 showed significant differences. However, no difference in haplotype frequencies was observed between cases and controls at rs152312 and SNP56. In the analysis of the small-artery-occlusive stroke group, no difference in allele or genotype frequencies was observed at any marker between cases and controls; the global haplotype frequency in rs152312 and SNP56 had a significant difference between cases and controls (P=0.0162); the frequency of haplotype C-A was higher in cases than in controls (P=0.0122). In conclusion, our present findings show that polymorphisms in the PDE4D gene are associated with an increased risk of ischaemic stroke in the Chinese Han population. The present study adds further support to the role of PDE4D in stroke.

Phosphodiesterase 4D and 5-lipoxygenase activating protein genes and risk of ischemic stroke in Sardinians

Genetic factors contribute to the risk of ischemic stroke (IS). The phosphodiesterase-4D (PDE4D) and the 5-lipoxygenase activating protein (ALOX5AP) genes were identified as contributors to stroke in an Icelandic population. In an attempt to better define the contributory role of PDE4D and ALOX5AP genes to the risk of IS in humans, we carried out the present association study in a well-characterized, earlier published, genetically homogenous population from the island of Sardinia, Italy. In this cohort, including 294 cases and 235 controls, age, hypertension, hypercholesterolemia, and atrial fibrillation represent risk factors for IS. The PDE4D gene was evaluated by four single nucleotide polymorphisms (SNP32, SNP45, SNP83, SNP87) and by the microsatellite AC008818-1; the ALOX5AP gene was characterized by three SNPs (SG13S32, SG13S89, ALO2A). The results of our study provide no evidence of association between any single PDE4D and ALOX5AP gene variant with the risk of IS in the Sardinian cohort. Haplotype analysis, including that constructed with allele 0 of microsatellite AC008818-1 and SNP45 of the PDE4D gene, was also negative. In conclusion, we found no evidence of association between PDE4D and ALOX5AP genes and the risk of IS in a genetically homogenous population from Sardinia.

Multilocus Bayesian meta-analysis of gene-disease associations

Meta-analysis is a vital tool in genetic epidemiology. However, meta-analyses to identify gene-disease associations are compromised when contributing studies have typed partially overlapping sets of markers. Currently, only marginal analyses are possible, and these are restricted to the subset of studies typing that marker. This does not allow full use of available data and leads to the confounding of marker effects by closely associated markers. We present a Bayesian approach that exploits prior information on underlying haplotypes to allow multi-marker analysis incorporating data from all relevant studies of a gene or region, irrespective of the markers typed. We present results from application of our approach to data on a possible association between PDE4D and ischemic stroke.

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.

Lack of association between variations of PDE4D and ischemic stroke in the Japanese population

BACKGROUND AND PURPOSE

After the first genomewide association study of ischemic stroke identified PDE4D as a susceptible gene, many replication studies have been conducted. However, the validity of the association has remained controversial because of the heterogeneity of both genetic markers and phenotypes.

METHODS

We investigated the association between variations of PDE4D and ischemic stroke by 3 methods: single-marker, haplotype, and tag-single nucleotide polymorphism (SNP) analyses. In the single-marker analysis, we evaluated the association using 2 large case-control samples (1112 cases and 1112 control subjects in a sample obtained from Kyushu, Japan, and 1711 cases and 1786 control subjects in BioBank Japan) and a prospective cohort with 14 years of follow-up. These samples were analyzed both separately and pooled. Haplotype and tag-SNP analyses were performed using the 2 case-control samples together.

RESULTS

In single-marker association tests, we found no significant association in the same direction among the 6 SNP reported in the initial study and ischemic stroke subtypes. Haplotype analysis revealed no significant association between the region around the 5'-end of the gene and combined atherothrombotic and cardioembolic infarction. Rs7730070, a SNP located around the 3'-end of PDE4D, showed the lowest nominal probability value by tag-SNP analysis but was not significant after adjustment for multiple testing (adjusted probability value =0.36).

CONCLUSIONS

These results suggest that variations in PDE4D are not associated with ischemic stroke risk in the Japanese population.

Stroke genetics--focus on PDE4D gene

Stroke is a complex disease comprising of a heterogenous group of disorders with multiple risk factors. Genetic predisposition to stroke does occur and has been documented in both animal models and human beings. However, a precise definition of genetic factors responsible for stroke is still lacking because research into the genetic basis of stroke presents some unique challenges. More commonly it seems to be a multifactorial polygenic disorder. Mutations in some candidate genes are likely to predispose or give protection against stroke. Several mutations in various genes have been found to be associated with stroke. However, we have a long way to go before we can accurately pinpoint the genes responsible for multifactorial stroke. Recently, the deCODE group has suggested an association between the phosphodiesterase 4D (PDE4D) gene and the risk of stroke in Icelanders. PDE4D is the first putative gene associated with common polygenic stroke. Specific variants of this gene have been shown to present risk for ischemic stroke in Icelanders. Replication studies in non-Icelanders have yielded variable results. There may be obvious racial differences in the prevalence of these mutations but still many questions remain unsolved regarding the role of PDE4D in stroke development.

Genetic polymorphisms for the study of multifactorial stroke

Single-gene disorders explain only a minority of stroke cases. Stroke represents a complex trait, which is usually assumed to be polygenic. On this topic, the role of a wide number of candidate genes has been investigated in stroke through association studies, with controversial results. Therefore, it is difficult for the clinician to establish the validity and the level of clinical applicability of the previously reported associations between genetic factors and stroke. This review is an update and an extensive analysis of the more recent association studies conducted in stroke. We evaluated a number of studies on several candidate genes (including F5, F2, FGA/FGB/FGG, F7, F13A1, vWF, F12, SERPINE1, ITGB3/PLA1/PLA2/ITGA2B, ITGA2, GP1BA, ACE, AGT, NOS3, APOE, LPL, PON1, PDE4D, ALOX5AP, MTHFR, MTR, and CBS), providing a final panel of genes and molecular variants. We categorized this panel in relation to the degree of association with stroke, supported by the results of meta-analyses and case-control studies. Our findings could represent a useful tool to address further molecular investigations and to realize more detailed meta-analyses.