Inducible nitric oxide synthase promoter polymorphism affords protection against cognitive dysfunction after carotid endarterectomy

Association of ATP8B3 gene polymorphisms with aspirin-exacerbated respiratory disease in asthmatics

BACKGROUND

Aspirin-exacerbated respiratory disease (AERD), an asthma phenotype, often presents with severe manifestations and it remains widely underdiagnosed because of insufficient awareness of the relationship between the ingestion of nonsteroidal anti-inflammatory drugs, including acetylsalicylic acid (ASA), and asthma exacerbation. Our previous genome-wide association study demonstrated an association between a single nucleotide polymorphism (SNP) of the ATP8B3 gene and the risk of AERD. This study examined AERD-related SNPs of the ATP8B3 gene in a large population.

METHODS

Twenty-five SNPs of ATP8B3 were genotyped with the GoldenGate assay using VeraCode microbeads in 141 asthmatics with AERD and 995 Aspirin-tolerant asthma (ATA). The genotype distribution was analyzed using logistic regression models. The declines in forced expiratory volume in 1 second (FEV1)following an ASA challenge were compared among the genotypes and haplotypes using a type III generalized linear model.

RESULTS

The minor allele frequencies (MAFs) of rs10421558 A>G in the 5'UTR and rs10403288 G>A in the intron were significantly lower in the AERD than the ATA [34.0% vs. 43.8%, OR = 0.66 (0.62-0.92), Pcorr = 0.03 and 28.4% vs. 35.4%, OR = 0.62 (0.59-0.89), Pcorr = 0.016, respectively]. BL1ht5 was significantly higher in the AERD [7.6% vs. 1.6%, OR = 12.23 (0.2-0.51), P = 4.7 × 10 -4 , Pcorr = 0.001]. Among them, rs10421558 A>G and BL1ht5 were associated with the percent decline in FEV1 on the oral ASA challenge test.

CONCLUSION

The minor allele of rs10421558 A>G in the 5'UTR may protect against the development of AERD via the increased production of ATP8B3.

Neurocognitive Function after Cardiac Surgery: From Phenotypes to Mechanisms

For half a century, it has been known that some patients experience neurocognitive dysfunction after cardiac surgery; however, defining its incidence, course, and causes remains challenging and controversial. Various terms have been used to describe neurocognitive dysfunction at different times after cardiac surgery, ranging from "postoperative delirium" to "postoperative cognitive dysfunction or decline." Delirium is a clinical diagnosis included in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Postoperative cognitive dysfunction is not included in the DSM-5 and has been heterogeneously defined, though a recent international nomenclature effort has proposed standardized definitions for it. Here, the authors discuss pathophysiologic mechanisms that may underlie these complications, review the literature on methods to prevent them, and discuss novel approaches to understand their etiology that may lead to novel treatment strategies. Future studies should measure both delirium and postoperative cognitive dysfunction to help clarify the relationship between these important postoperative complications.

Genetic Variants in the Transcriptional Regulatory Region of the ALOX5AP gene and Susceptibility to Ischemic Stroke in Chinese Populations

No coding sequence variants of the ALOX5AP gene that lead to amino acid substitutions have been identified. A two-stage study design was used to explore the relationship between variants in the transcriptional regulatory region of ALOX5AP gene and ischemic stroke (IS) risk in Chinese populations. IS was determined using CT and/or MRI. First, 18 SNPs, located in the upstream promoter region of ALOX5AP gene, were genotyped in 200 IS patients and 200 controls. And one potential associated SNP (rs17222919) was identified (P = 0.005,OR = 0.623, 95% CI: 0.448~0.866). Next, another independent case-control cohort comprising 810 IS patients and 825 matched controls was recruited to investigate the role of rs17222919, rs9579646 polymorphisms and their haplotypes in IS risk. The G allele frequency of rs17222919 in the IS group was significantly lower than that in control group (P = 0.007, OR = 0.792, 95% CI: 0.669~0.937). T-A and G-A haplotypes were associated with IS (P = 0.001,OR = 1.282, 95% CI:1.100~1.495; P = 0.0001, OR = 0.712, 95% CI: 0.598~0.848; respectively). Our study providesevidence that rs17222919 is a potential genetic protective factor against IS. Furthermore, the T-A haplotype is a risk factor and the G-A haplotype is a protective factor against IS in Chinese population.

Impact of Cognitive Dysfunction on Survival in Patients With and Without Statin Use Following Carotid Endarterectomy

BACKGROUND:

Early cognitive dysfunction (eCD) is a subtle form of neurological injury observed in ∼25% of carotid endarterectomy (CEA) patients. Statin use is associated with a lower incidence of eCD in asymptomatic patients having CEA.

OBJECTIVE:

To determine whether eCD status is associated with worse long-term survival in patients taking and not taking statins.

METHODS:

This is a post hoc analysis of a prospective observational study of 585 CEA patients. Patients were evaluated with a battery of neuropsychometric tests before and after surgery. Survival was compared for patients with and without eCD stratifying by statin use. At enrollment, 366 patients were on statins and 219 were not. Survival was assessed by using Kaplan-Meier methods and multivariable Cox proportional hazards models.

RESULTS:

Age ≥75 years (P = .003), diabetes mellitus (P < .001), cardiac disease (P = .02), and statin use (P = .014) are significantly associated with survival univariately (P < .05) by use of the log-rank test. By Cox proportional hazards model, eCD status and survival adjusting for univariate factors within statin and nonstatin use groups suggested a significant effect by association of eCD on survival within patients not taking statin (hazard ratio, 1.61; 95% confidence interval, 1.09–2.40; P = .018), and no significant effect of eCD on survival within patients taking statin (hazard ratio, 0.98; 95% confidence interval, 0.59–1.66; P = .95).

CONCLUSION:

eCD is associated with shorter survival in patients not taking statins. This finding validates eCD as an important neurological outcome and suggests that eCD is a surrogate measure for overall health, comorbidity, and vulnerability to neurological insult.

A promoter polymorphism (rs17222919, -1316T/G) of ALOX5AP gene is associated with decreased risk of ischemic stroke in two independent Chinese populations

No coding sequence variants of the gene encoding 5-lipoxygenase-activating protein (ALOX5AP) leading to amino acid substitutions have been identified. Therefore, variants in the ALOX5AP promoter region have received attention recently. The purpose of this study was to explore whether the promoter polymorphism rs17222919 is involved in the etiology of ischemic stroke (IS) in the Chinese Han population. We investigated the rs17222919 polymorphism by TaqMan genotyping in two independent Chinese Han samples: the first comprised 910 IS patients and 925 healthy inhabitants from the northern Henan Province, while the second included 1003 IS patients and 889 healthy controls from the southern Henan Province. Functional characterization of rs17222919 was performed by an in vitro luciferase assay. After adjusting for conventional risk factors, the G allele frequencies in the IS groups were significantly lower than that in the control groups of the two independent Chinese cohorts (19.0% vs. 22.9%, P = 0.004, odds ratio (OR) = 0.792, 95% confidence interval (CI) = 0.675-0.929; 18.8% vs. 22.9%, P = 0.002, OR = 0.782, 95% CI = 0.668-0.915, respectively). This was also observed in the large-artery atherosclerosis (LAA) and stroke of other undetermined etiology (SUE) subtypes (P = 0.019, OR = 0.815, 95% CI = 0.687-0.967; P = 0.021, OR = 0.815, 95% CI = 0.685-0.970, respectively). Additionally, the TG genotype and G allele frequencies were significantly lower in the IS compared with the control group in two female cohorts (P<0.05). Finally, the in vitro luciferase assay demonstrated that the G allele has a significantly lower transcription activity than the T allele (P = 0.031). Our study provides evidence that the promoter single nucleotide polymorphism (SNP) rs17222919 is a potential genetic protective factor for IS in the Chinese Han population.

Radiographic absence of the posterior communicating arteries and the prediction of cognitive dysfunction after carotid endarterectomy

OBJECT

Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD.

METHODS

Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA.

RESULTS

Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43-64.92, p = 0.02).

CONCLUSIONS

The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 ( http://www.clinicaltrials.gov ).

Neurocognitive functioning after carotid revascularization: a systematic review

BACKGROUND

The objective of this study was to review the recent literature regarding the neurocognitive consequences of carotid endarterectomy (CEA) and carotid stenting (CAS).

METHODS AND RESULTS

A PubMed and Web of Science search was conducted using the key words 'carotid' in combination with 'cognitive', 'cognition', 'neurocognition', 'neurocognitive', 'neuropsychology', and 'neuropsychological'. Bibliographies of relevant articles were cross-referenced. We included 37 studies published since 2007 of which 18 examined CEA, 12 CAS, and 7 compared CEA to CAS. There is a wide variability in the reported neurocognitive outcome following CEA and CAS. Nonetheless, none of the included studies unveiled significant differences between CEA and CAS on postoperative neurocognitive functioning. Postoperative changes observed for CEA and CAS separately seem limited to a small percentage (around 10-15%) of patients and can either present as an improvement or impairment.

KEY MESSAGES

The available data seem to suggest that no obvious cognitive differences between CAS and CEA can be observed after intervention. Both improvement and deterioration in cognitive functioning can be observed following CAS or CEA. Methodological differences such as patient heterogeneity, implementation and type of control groups, type of psychometric tests used, statistical analyses, or timing of the assessments play an important role in explaining the sometimes divergent results of the included studies. Large-scale and methodologically solid studies comparing CEA and CAS on neurocognitive outcome remain warranted. Future studies should implement adequate control groups to correct for practice effects in the target groups.

Hereditary vulnerabilities to post-operative cognitive dysfunction and dementia

In view of multiple prospective investigations reporting an incidence of 10% or greater in elderly patients after cardiac and non-cardiac procedures, it is surprising that no families, twins or even individual cases have been reported with persistent post-operative cognitive dysfunction (POCD) or post-operative dementia (POD) that is otherwise unexplained. As POCD and POD research has shifted in recent years from surgical and anesthetic variables to predictors of intrinsic, patient-specific susceptibility, a number of markers based on DNA sequence variation have been investigated. Nevertheless, no heritable, genomic indices of persistent POCD or post-operative dementia lasting 3 months or longer after surgery have been identified to date. The present manuscript surveys challenges confronting the search for markers of heritable vulnerability to POCD and POD, and proposes steps forward to be taken now, including the addition of surgical and anesthetic descriptors to ongoing longitudinal dementia protocols and randomized clinical trials (RCTs) comprising serial psychometric testing, and a fresh focus on phenotypes and genotypes shared between outliers with "extreme" POCD and POD traits.

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.

Complement polymorphisms and cognitive dysfunction after carotid endarterectomy

OBJECT

The role of genetic polymorphisms in the neurological outcome of patients after carotid endarterectomy (CEA) remains unclear. There are single nucleotide polymorphisms (SNPs) that predispose patients to postoperative cognitive dysfunction (CD). We aim to assess the predictability of three complement cascade-related SNPs for CD in patients having CEAs.

METHODS

In 252 patients undergoing CEA, genotyping was performed for the following polymorphisms: complement component 5 (C5) rs17611, mannose-binding lectin 2 (MBL2) rs7096206, and complement factor H (CFH) rs1061170. Differences among genotypes were analyzed via the chi-square test. Patients were evaluated with a neuropsychometric battery for CD 1 day and 1 month after CEA. A multiple logistic regression model was created. All variables with univariate p < 0.20 were included in the final model.

RESULTS

The C5 genotypes A/G (OR 0.26, 95% CI 0.11-0.60, p = 0.002) and G/G (OR 0.22, 95% CI 0.09-0.52, p < 0.001) were significantly associated with lower odds of exhibiting CD at 1 day after CEA compared with A/A. The CFH genotypes C/T (OR 3.37, 95% CI 1.69-6.92, p < 0.001) and C/C (OR 3.67, 95% CI 1.30-10.06, p = 0.012) were significantly associated with higher odds of exhibiting CD at 1 day after CEA compared with T/T. Statin use was also significantly associated with lower odds of exhibiting CD at 1 day after CEA (OR 0.43, 95% CI 0.22-0.84, p = 0.01). No SNPs were significantly associated with CD at 1 month after CEA.

CONCLUSIONS

The presence of a deleterious allele in the C5 and CFH SNPs may predispose patients to exhibit CD after CEA. This finding supports previous data demonstrating that the complement cascade system may play an important role in the development of CD. These findings warrant further investigation.

Polymorphisms in complement component 3 (C3F) and complement factor H (Y402H) increase the risk of postoperative neurocognitive dysfunction following carotid endarterectomy

BACKGROUND

Up to 28% of patients undergoing carotid endarterectomy (CEA) are estimated to experience neurocognitive dysfunction following surgery. The complement cascade plays a central role in ischaemia-reperfusion injury. The authors investigated the effect of common polymorphisms in the complement component 3 (C3F) and complement factor H (CFH Y402H) genes on incidence of neurocognitive dysfunction post-CEA.

METHODS

This study examined a nested cohort of prospectively recruited patients receiving elective CEA, who were genotyped for the C3F or Y402H polymorphisms. Each patient underwent a standard battery of eight neuropsychometric tests before, and 1 day and 30 days after, surgery.

RESULTS

57 of 142 (40%) CEA patients had at least one copy of the C3F allele (C3F+), and 17 of 137 (12%) patients had two copies of the CFH Y402H allele (Y402H++). At postoperative day 1, patients were three times (OR 3.05, p=0.045) or six times (OR 6.41, p=0.006) more likely to experience moderate-to-severe neurocognitive dysfunction if they carried the C3F+ or Y402H++ genotype, respectively. Patients with both risk genotypes had an almost eightfold risk of dysfunction (OR 7.67, p=0.046). Right-hand-dominant C3F+ subjects undergoing right-side CEA performed significantly worse on tests of visuospatial function than C3F- subjects. At day 30, C3F+ and Y402H++ genotypes trended towards significance as predictors of dysfunction (p=0.07 and p=0.22, respectively).

CONCLUSION

The C3F and Y402H polymorphisms are strong independent predictors of moderate-to-severe neurocognitive dysfunction at 1 day following CEA. Furthermore, patients undergoing right-sided CEA are predisposed to deficits associated with cortex ipsilateral to the operative carotid artery.

Regulation of the expression of inducible nitric oxide synthase

Nitric oxide (NO) generated by the inducible isoform of nitric oxide synthase (iNOS) is involved in complex immunomodulatory and antitumoral mechanisms and has been described to have multiple beneficial microbicidal, antiviral and antiparasital effects. However, dysfunctional induction of iNOS expression seems to be involved in the pathophysiology of several human diseases. Therefore iNOS has to be regulated very tightly. Modulation of expression, on both the transcriptional and post-transcriptional level, is the major regulation mechanism for iNOS. Pathways resulting in the induction of iNOS expression vary in different cells or species. Activation of the transcription factors NF-kappaB and STAT-1alpha and thereby activation of the iNOS promoter seems to be an essential step for the iNOS induction in most human cells. However, at least in the human system, also post-transcriptional mechanisms involving a complex network of RNA-binding proteins build up by AUF1, HuR, KSRP, PTB and TTP is critically involved in the regulation of iNOS expression. Recent data also implicate regulation of iNOS expression by non-coding RNAs (ncRNAs).