Racial differences in P2Y12 inhibitor responsiveness in patients undergoing neuro-endovascular procedures: A cohort from the Middle East

BACKGROUND

Data on P2Y12 inhibitors responsiveness from the middle east is scarce. We sought to investigate patient responsiveness to P2Y12 inhibitors within a cohort of major races that characterize the UAE population. The secondary objective was to assess risk factors for hyper and hypo-responsiveness in this population.

METHODS

We conducted a cross-sectional study on adults who received either clopidogrel or ticagrelor treatments and had platelet responsiveness testing before undergoing neuro-endovascular interventions at our quaternary care hospital between March 2015 and April 2019.

RESULTS

During the study period, 249 subjects met the inclusion criteria. Overall, 17.3 % were hyper-responsive and 25.7 % were hypo-responsive to P2Y12 inhibitors. When comparing between the P2Y12 inhibitors, rates of hyper-responsiveness were significantly higher to ticagrelor when compared to clopidogrel (11 versus 6 %, p = 0.02 respectively). Contrarily, hypo-responsiveness rates were significantly higher in clopidogrel treated patients compared to their ticagrelor treated counterparts (23 versus 2 %, p < .001 respectively). Patients of Middle-Eastern origin showed a significantly higher rate of hypo-responsiveness to both clopidogrel and ticagrelor when compared to other races (41.1 % and 26.7 %, P < 0.001 respectively). Asians showed the highest rates of hyper-responsiveness for both agents. Multivariate logistic regression analysis showed that proton pump inhibitors and statin combination, (OR: 6.39, 95 %CI [1.60, 25.392]), and Middle East vs. Indian subcontinent patients (OR: 4.67, 95 %CI [1.79-12.14]) were independent predictors of hypo-responsiveness to both P2Y12 inhibitors.

CONCLUSION

This study demonstrated a high rate of hypo-responsiveness to P2Y12 inhibitors in a UAE cohort of patients undergoing neuro-endovascular procedures. In addition, therapeutic responsiveness to P2Y12 inhibitors varied markedly based on the racial background. Future larger studies are needed to evaluate genetic variations that may contribute to this rate of hypo-responsiveness in our population.

Hyper-responsiveness to warfarin in a young patient with the VKORC1 -1639GA/CYP2C9*1*46 genotype: a case report

BACKGROUND

Warfarin is the most widely used oral anticoagulant; nevertheless, dosing of warfarin is problematic for clinicians worldwide. Inter-individual variability in response to warfarin is attributed to genetic as well as non-genetic factors. Pharmacogenomics studies have identified variants in CYP2C9 and VKORC1 genes as significant predictors of warfarin dose, however, phenotypes of rare variants are not well characterized.

CASE PRESENTATION

We report a case of hyper-responsiveness to warfarin in a 22-year-old outpatient with Crohn's disease who presented with a swollen, red, and painful left calf. Deep venous thrombosis (DVT) in the left lower extremity was confirmed via ultrasonography, and hence, anticoagulation therapy of heparin and concomitant warfarin was initiated. Warfarin dose of 7.5 mg/day was estimated by the physician based on clinical factors. Higher than the expected international normalized ratio (INR) value of 4.5 necessitated the reduction of the warfarin dose to 5 and eventually to 2.5 mg/day to reach a therapeutic INR value of 2.6. Pharmacogenetic profiling of the VKORC1 -1639G > A and CYP2C9 *2, *3, *4, *5, *8, *14, *20, *24, *26, *33, *40, *41, *42, *43, *45, *46, *55, *62, *63, *66, *68, *72, *73 and *78 revealed a VKORC1-1639GA/CYP2C9*1*46 genotype. The lower catalytic activity of the CYP2C9*46 (A149T) variant was previously reported in in vitro settings.

CONCLUSIONS

This is the first report on a case of warfarin hyper-responsive phenotype of a patient with the heterozygous CYP2C9*1*46 polymorphism.

A theoretical model of inflammation- and mechanotransduction-driven asthmatic airway remodelling

Inflammation, airway hyper-responsiveness and airway remodelling are well-established hallmarks of asthma, but their inter-relationships remain elusive. In order to obtain a better understanding of their inter-dependence, we develop a mechanochemical morphoelastic model of the airway wall accounting for local volume changes in airway smooth muscle (ASM) and extracellular matrix in response to transient inflammatory or contractile agonist challenges. We use constrained mixture theory, together with a multiplicative decomposition of growth from the elastic deformation, to model the airway wall as a nonlinear fibre-reinforced elastic cylinder. Local contractile agonist drives ASM cell contraction, generating mechanical stresses in the tissue that drive further release of mitogenic mediators and contractile agonists via underlying mechanotransductive signalling pathways. Our model predictions are consistent with previously described inflammation-induced remodelling within an axisymmetric airway geometry. Additionally, our simulations reveal novel mechanotransductive feedback by which hyper-responsive airways exhibit increased remodelling, for example, via stress-induced release of pro-mitogenic and pro-contractile cytokines. Simulation results also reveal emergence of a persistent contractile tone observed in asthmatics, via either a pathological mechanotransductive feedback loop, a failure to clear agonists from the tissue, or a combination of both. Furthermore, we identify various parameter combinations that may contribute to the existence of different asthma phenotypes, and we illustrate a combination of factors which may predispose severe asthmatics to fatal bronchospasms.

Relationship between serum IgA level and allergy/asthma

BACKGROUND/AIMS

Mucosal immunoglobulin A (IgA) may prevent the entrance of allergens. This study examined the relationship between serum IgA levels (within the normal range) and sensitization to house dust mites (HDM) or airway hyper-responsiveness (AHR).

METHODS

The clinical records of 1,136 adult patients with suspected asthma, for whom test data for serum IgA level and methacholine-AHR were available, were reviewed retrospectively. The AHR/allergy indices were compared among patient groups with low (<140 mg/dL, group I), intermediate (140 to 280 mg/dL, group II), or high (≥280 mg/dL, group III) IgA levels in serum.

RESULTS

The HDM skin sensitization rate progressively decreased from 30.0% in group I (n = 139) to 26.8% and 18.5% in groups II (n = 684) and III (n = 313), respectively (p = 0.003). Although both the HDM sensitization degree and the IgA level were significantly related to age, the adjusted odds ratio (OR) of association of a high IgA level (≥ 280 mg/dL) with HDM sensitization was significant (0.617; 95% confidence interval [CI], 0.415 to 0.916; p = 0.017). Among younger subjects (≤ 45 years of age) with AHR, the prevalence of moderate/severe AHR progressively decreased (70.6%, 52.3%, and 47.1% in groups I, II, and III [n = 34, 149, and 51]), respectively (p = 0.045). The IgA < 140 mg/dL was a significant risk factor for moderate/severe AHR (OR, 2.306; 95% CI, 1.049 to 5.071; p = 0.038).

CONCLUSIONS

Sensitization to HDM and methacholine-AHR were significantly associated with serum IgA levels in suspected asthmatics, even when those levels were normal.

Autism and peripheral hearing loss: a systematic review

OBJECTIVE

To systematically review the literature describing the relationship between autism spectrum disorder (ASD) and peripheral hearing loss including literature recommendations for audiological assessment and auditory habilitation in cases where peripheral hearing loss and ASD coexist.

DATA SOURCES

Published studies indexed in MEDLINE (1948-2011).

REVIEW METHODS

The search strategy identified 595 potential studies. After a review of the titles, 115 abstracts were reviewed and 39 articles were retrieved and assessed independently by at least two authors for possible inclusion. 22 articles pertained to children with ASD and peripheral hearing loss, hearing assessment in children with ASD, audiological habilitation for children with ASD or hyper-responsiveness in children with ASD. 17 further studies were garnered from the reference section of the 22 papers.

RESULTS

Controversy exists in the literature regarding prevalence of hearing impairment among individuals with ASD. In cases where ASD and hearing impairment co-exist, diagnosis of one condition often leads to a delay in diagnosing the other. Audiological assessment can be difficult in children with ASD and test-retest reliability of behavioural thresholds can be poor. In cases where hearing impairment exists and hearing aids or cochlear implantation are recommended, devices are often fit with special considerations for the child with ASD. Hyper-responsiveness to auditory stimuli may be displayed by individuals with ASD. Evidence or the suspicion of hyper-responsiveness may be taken into consideration when fitting amplification and planning behavioural intervention.

CONCLUSIONS

Prevalence rates of hearing impairment among individuals with ASD continue to be debated. At present there is no conclusive evidence that children with ASD are at increased risk of peripheral hearing loss. A complete audiological assessment is recommended in all cases where ASD is suspected so as not to delay the diagnosis of hearing impairment in the event that hearing loss and ASD co-exist. Objective assessment measures should be used to confirm behavioural testing in order to ensure reliability of audiological test results. Fitting of hearing aids or cochlear implantation are not contraindicated when hearing loss is present in children with ASD; however, success with these devices can be variable.