Treatment of intracardiac thrombi using ultra-slow low-dose thrombolytic therapy: A case report

A 57-year-old male with previously known severe primary mitral regurgitation was admitted to the intensive care unit (ICU) due to massive venous thromboembolism, associated with right ventricular dysfunction and two large mobile right atrial thrombi. Due to deterioration in his clinical condition despite standard treatment with unfractionated heparin, it was decided to use an ultra-slow low-dose thrombolysis protocol, which consisted of a 24-hour infusion of 24 mg of alteplase at a rate of 1 mg per hour, without initial bolus. The treatment was continued for 48 consecutive hours, with clinical improvement and resolution of the intracardiac thrombi and no complications. One month after ICU admission, successful mitral valve repair surgery was conducted. This case demonstrates that ultra-slow low-dose thrombolysis is a valid bailout treatment option in patients with large intracardiac thrombi refractory to the standard approach.

Weaning from mechanical ventilation in intensive care units across 50 countries (WEAN SAFE): a multicentre, prospective, observational cohort study

BACKGROUND

Current management practices and outcomes in weaning from invasive mechanical ventilation are poorly understood. We aimed to describe the epidemiology, management, timings, risk for failure, and outcomes of weaning in patients requiring at least 2 days of invasive mechanical ventilation.

METHODS

WEAN SAFE was an international, multicentre, prospective, observational cohort study done in 481 intensive care units in 50 countries. Eligible participants were older than 16 years, admitted to a participating intensive care unit, and receiving mechanical ventilation for 2 calendar days or longer. We defined weaning initiation as the first attempt to separate a patient from the ventilator, successful weaning as no reintubation or death within 7 days of extubation, and weaning eligibility criteria based on positive end-expiratory pressure, fractional concentration of oxygen in inspired air, and vasopressors. The primary outcome was the proportion of patients successfully weaned at 90 days. Key secondary outcomes included weaning duration, timing of weaning events, factors associated with weaning delay and weaning failure, and hospital outcomes. This study is registered with ClinicalTrials.gov, NCT03255109.

FINDINGS

Between Oct 4, 2017, and June 25, 2018, 10 232 patients were screened for eligibility, of whom 5869 were enrolled. 4523 (77·1%) patients underwent at least one separation attempt and 3817 (65·0%) patients were successfully weaned from ventilation at day 90. 237 (4·0%) patients were transferred before any separation attempt, 153 (2·6%) were transferred after at least one separation attempt and not successfully weaned, and 1662 (28·3%) died while invasively ventilated. The median time from fulfilling weaning eligibility criteria to first separation attempt was 1 day (IQR 0-4), and 1013 (22·4%) patients had a delay in initiating first separation of 5 or more days. Of the 4523 (77·1%) patients with separation attempts, 2927 (64·7%) had a short wean (≤1 day), 457 (10·1%) had intermediate weaning (2-6 days), 433 (9·6%) required prolonged weaning (≥7 days), and 706 (15·6%) had weaning failure. Higher sedation scores were independently associated with delayed initiation of weaning. Delayed initiation of weaning and higher sedation scores were independently associated with weaning failure. 1742 (31·8%) of 5479 patients died in the intensive care unit and 2095 (38·3%) of 5465 patients died in hospital.

INTERPRETATION

In critically ill patients receiving at least 2 days of invasive mechanical ventilation, only 65% were weaned at 90 days. A better understanding of factors that delay the weaning process, such as delays in weaning initiation or excessive sedation levels, might improve weaning success rates.

FUNDING

European Society of Intensive Care Medicine, European Respiratory Society.

Neurocognitive and psychological comorbidities in patients with self-limited centrotemporal spike epilepsy. A case-control study

INTRODUCTION

Self-limited epilepsy with centrotemporal spikes (SeLECTS) is the most frequent self-limited focal epilepsy. This study aimed to assess the cognitive, behavioral, and other neuropsychological aspects of children with SeLECTS, and compare them with a control group.

SUBJECTS AND METHODS

A case-control study was carried out between January and May 2022. Patients with SeLECTS, aged between 6 and 18 years, and followed-up at our hospital were selected for inclusion in the study. For each case, two age-matched controls were opportunistically recruited. All the participants performed the EpiTrack Junior® test, and their parents filled out the Child Behavior Checklist (CBCL).

RESULTS

Eighteen patients were included (mean age: 8.7 ± 1.7 years). At SeLECTS' diagnosis, 83% of cases had adequate psychomotor development, and 17% had a neurodevelopmental disorder. The EpiTrack-Junior® and the Total Problems CBCL scores were not influenced by the laterality of the epileptic focus nor by the number of seizures. 61% of cases showed mild or significant impairment in the EpiTrack-Junior® test versus 44% of controls (p = 0.712), and 39% of cases vs. 14% of controls had 'clinically significant' scores on the Total Problems CBCL scale (p = 0.087).

CONCLUSIONS

Although this study did not find statistically significant differences between cases and controls, it should be noted that most patients with SeLECTS had a mild or significant disability in executive functions. A considerable percentage of cases were in the pathological range regarding emotional/behavioral problems. This study highlights the importance of screening the cognitive, behavioral, and emotional problems in all patients with SeLECTS.

Xanthones for melanogenesis inhibition: Molecular docking and QSAR studies to understand their anti-tyrosinase activity

The human skin is constantly exposed to external factors that affect its integrity, UV radiation being one of the main stress factors. The repeated exposure to this radiation leads to increased production of Reactive Oxygen Species (ROS) which activate a series of processes involved in photoaging. Excessive UV exposure also exacerbates melanin production leading to a variety of pigmentation disorders. Xanthones are reported to exhibit properties that prevent deleterious effects of UV exposure and high levels of ROS in the organism, so in this work a wide library of xanthones with different patterns of substitution was synthesized and tested for their inhibitory activity against the skin enzymes tyrosinase, elastase, collagenase and hyaluronidase, many of which were evaluated for the first time. Most of the compounds were tyrosinase inhibitors, with the best one (xanthone 27) presenting an IC₅₀ of 1.9 µM, which is approximately 6 times lower than the IC₅₀ of the positive control kojic acid. Concerning the other enzymes, only one compound presented IC₅₀ lower than 150 µM in elastase inhibition (xanthone 14 = 91.8 µM) and none in collagenase and hyaluronidase inhibition. A QSAR model for tyrosinase inhibitory activity was built using six molecular descriptors, with a partial negative surface area descriptor and the relative number of oxygen atoms being positively contributing to the tyrosinase inhibitory activity. Docking using AutoDock Vina shows that all the tested compounds have more affinity to mushroom tyrosinase than kojic acid. Docking results implied that the tyrosinase inhibitory mechanisms of xanthonic derivatives are attributed to an allosteric interaction. Taken together, these data suggest that xanthones might be useful scaffolds for the development of new and promising candidates for the treatment of pigmentation-related disorders and for skin whitening cosmetic products.

1115 Ultra-slow low-dose thrombolytic therapy as an option of treatment in intracardiac thrombus: a case report

We present a case of a 57-year-old male with previously known primary severe mitral regurgitation, who was admitted to the ICU due to massive venous thromboembolism with associated right ventricle dysfunction and with two large mobile right atrial thrombi (2.4 x 1.5 cm and 3.6 x 3.7 cm). Despite of five days with a therapeutic aPTT achieved with unfractionated heparin (UFH), a TTE showed deterioration of the right ventricle systolic function, persistence of the right atrial masses with similar dimensions together with new mobile thrombi on the coronary sinus and on the right pulmonary artery. Due to deterioration of his clinical condition and given the refractoriness to the classical treatment with UFH, it was decided to administer an ultra-slow low-dose thrombolysis protocol, which consisted in a 24-hour infusion of 24 mg of alteplase at a rate of 1 mg per hour, without bolus. The treatment was continued by 48 consecutive hours, with clinical improvement and important reduction of the right atrial masses with resolution of the coronary sinus and right pulmonary artery thrombi. The patient started hypocoagulation with warfarin bridging with low molecular weight heparin (LMWH). Seven days after alteplase discontinuation there was complete resolution of the intracardiac thrombi. One month after ICU admission a successful mitral valve replacement surgery was conducted. Three months after discharge, the patient is in functional New York Heart Association (NYHA) class I with no cardiovascular events or hospitalizations. This case demonstrates that ultra-slow low-dose thrombolysis is a valid bailout treatment option in patients with large intracardiac thrombi refractory to anticoagulation.

Abstract 1115 Figure. TTE showing right atrial masses

Naphthoquinoxaline metabolite of mitoxantrone is less cardiotoxic than the parent compound and it can be a more cardiosafe drug in anticancer therapy

Mitoxantrone (MTX) is an antineoplastic agent used to treat several types of cancers and on multiple sclerosis, which shows a high incidence of cardiotoxicity. Still, the underlying mechanisms of MTX cardiotoxicity are poorly understood and the potential toxicity of its metabolites scarcely investigated. Therefore, this work aimed to synthesize the MTX-naphthoquinoxaline metabolite (NAPHT) and to compare its cytotoxicity to the parent compound in 7-day differentiated H9c2 cells using pharmacological relevant concentrations (0.01-5 µM). MTX was more toxic in equivalent concentrations in all cytotoxicity tests performed [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction, neutral red uptake, and lactate dehydrogenase release assays] and times tested (24 and 48 h). Both MTX and NAPHT significantly decreased mitochondrial membrane potential in 7-day differentiated H9c2 cells after a 12-h incubation. However, energetic pathways were affected in a different manner after MTX or NAPHT incubation. ATP increased and lactate levels decreased after a 24-h incubation with MTX, whereas for the same incubation time and concentrations, NAPHT did not cause any significant effect. The increased activity of ATP synthase seems responsible for MTX-induced increases in ATP levels, as oligomycin (an inhibitor of ATP synthase) abrogated this effect on 5 µM MTX-incubated cells. 3-Methyladenine (an autophagy inhibitor) was the only molecule to give a partial protection against the cytotoxicity produced by MTX or NAPHT. To the best of our knowledge, this was the first broad study on NAPHT cardiotoxicity, and it revealed that the parent drug, MTX, caused a higher disruption in the energetic pathways in a cardiac model in vitro, whereas autophagy is involved in the toxicity of both compounds. In conclusion, NAPHT is claimed to largely contribute to MTX-anticancer properties; therefore, this metabolite should be regarded as a good option for a safer anticancer therapy since it is less cardiotoxic than MTX.

Can behavioural differences in Platypus cylindrus (Coleoptera: Platypodinae) from Portugal and Tunisia be explained by genetic and morphological traits?

Platypus cylindrus is an important wood borer of cork oak trees (Quercus suber) in the Mediterranean region, namely Portugal, Morocco and Algeria where its presence has drastically increased in the past few decades. On the contrary, the insect is not a relevant pest in Tunisia. The aim of this work is to analyze morphological and genetic differences among Tunisian and Portuguese populations in order to understand their role in the diverse population dynamics (e.g., aggressiveness) of the insect. The information could be used as a novel tool to implement protective measures. Insects were collected from cork oak stands in Tunisia (Ain Beya, Babouch and Mzara) and Portugal (Chamusca and Crato). Morphological traits of female and male mycangial pits were determined, using scanning electron microscopy but no significant differences were found. Genetic differences were analyzed using nuclear (internal simple sequence repeat polymerase chain reaction) and mitochondrial (cytochrome oxidase I (COI)) molecular markers. The results showed a very low level of intraspecific polymorphism and genetic diversity. The alignment of COI sequences showed high percentage of identical sites (99%) indicating a very low variation in nucleotide composition. Other variables related with the ecology of the insect and its associated fungi must be studied for a better understanding of the differences in the insect population's dynamic in Mediterranean countries.

HLA alleles and HLA-B27 haplotypes associated with susceptibility and severity of ankylosing spondylitis in a Portuguese population

Human leukocyte antigen (HLA)-B27 is the mostly known major histocompatibility complex (MHC) gene associated with ankylosing spondylitis (AS). Nonetheless, there is substantial evidence that other MHC genes appear to be associated with the disease, although it has not yet been established whether these associations are driven by direct associations or by linkage disequilibrium (LD) mechanisms. We aimed to investigate the contributions of HLA class I and II alleles and B27-haplotypes for AS in a case-control study. A total of 188 HLA-B27 AS cases and 189 HLA-B27 healthy controls were selected and typed for HLA class I and II by the Luminex polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSOP) method. Allelic and haplotypic distributions were estimated by maximum likelihood method using Arlequin v3.11 and statistical analysis were performed by Stata10.1. No associations were found between non-HLA-B27 loci and AS susceptibility, but several associations were observed for phenotypic features of the disease. DRB1*08 was identified as a risk factor for uveitis and DQB1*04 seems to provide protection for AS severity (functional, metrological and radiological indexes). A*02/B27/C*02/DRB1*01/DQB1*05 [P<0.0001; odds ratio (OR) = 39.06; 95% confidence interval (CI) (2.34-651)] is the only haplotype that seems to confer susceptibility to AS. Moreover, the haplotype A*02/B27/C*01/DRB1*08/DQB1*04 seems to provide protection for disease functional and radiological repercussions. Our findings are compatible with the hypothesis that other genes within the HLA region besides HLA-B27 might play some role in AS susceptibility and severity.

A century of thioxanthones: through synthesis and biological applications

The interest in the synthesis and applications of thioxanthones, dibenzo-gamma-thiopyrones, started in the beginning of the 20th century. Thioxanthones are traditionally synthesized via benzophenone, diarylthioether or diarylthioester intermediates. In recent years, more efficient and cleaner synthetic methodologies are being applied to obtain thioxanthone derivatives, especially for photochemical applications. Considering biological activities, the first thioxanthone introduced in therapy in 1945 was Miracil D, as an antischistosomal agent. Since then, the variety of studies of biological/ pharmacological activities of thioxanthones led to the discovery of new agents and to the disclosure of their mechanisms of action. Moreover, the ability to sensitize cancer cells suggested new and promising applications in chemotherapy. New antitumor derivatives are being developed by molecular modifications such as isosterism (aza-thioxanthones and aminoethylthioxanthones) or hybridation (psorospermine and acronycin analogues). The last generation of antitumor thioxanthones rendered a derivative, SR271425, with an excellent preclinical antitumor efficacy. The last decade has been excited in the research of thioxanthones with important achievements in both synthesis and biochemical applications, especially in order to dissociate the antitumor activity from the toxicity of drug candidates. Recently, thioxanthones emerged as dual inhibitors of P-glycoprotein and tumor cell growth. It is expected that in the following years new analogues with the thioxanthone scaffold emerge in the field of anticancer therapy, with enhanced antitumor activity and without serious side effects.

Enoxacin inhibits growth of prostate cancer cells and effectively restores microRNA processing

Prostate cancer (PCa) is one of the most incident malignancies worldwide. Although efficient therapy is available for early-stage PCa, treatment of advanced disease is mainly ineffective and remains a clinical challenge. microRNA (miRNA) dysregulation is associated with PCa development and progression. In fact, several studies have reported a widespread downregulation of miRNAs in PCa, which highlights the importance of studying compounds capable of restoring the global miRNA expression. The main aim of this study was to define the usefulness of enoxacin as an anti-tumoral agent in PCa, due to its ability to induce miRNA biogenesis in a TRBP-mediated manner. Using a panel of five PCa cell lines, we observed that all of them were wild type for the TARBP2 gene and expressed TRBP protein. Furthermore, primary prostate carcinomas displayed normal levels of TRBP protein. Remarkably, enoxacin was able to decrease cell viability, induce apoptosis, cause cell cycle arrest, and inhibit the invasiveness of cell lines. Enoxacin was also effective in restoring the global expression of miRNAs. This study is the first to show that PCa cells are highly responsive to the anti-tumoral effects of enoxacin. Therefore, enoxacin constitutes a promising therapeutic agent for PCa.

Three decades of P-gp inhibitors: skimming through several generations and scaffolds

Many tumor cells become resistant to commonly used cytotoxic drugs due to the overexpression of ATP-binding cassette (ABC) transporters, namely P-glycoprotein (P-gp). The discovery of the reversal of multidrug resistance (MDR) by verapamil occured in 1981, and in 1968 MDR Chinese hamster cell lines were isolated for the first time. Since then, P-gp inhibitors have been intensively studied as potential MDR reversers. Initially, drugs to reverse MDR were not specifically developed for inhibiting P-gp; in fact, they had other pharmacological properties, as well as a relatively low affinity for MDR transporters. An example of this first generation P-gp inhibitors is verapamil. The second generation included more specific with less side-effect inhibitors, such as dexverapamil or dexniguldipine. A third generation of P-gp inhibitors comprised compounds such as tariquidar, with high affinity to P-gp at nanomolar concentrations. These generations of inhibitors of P-gp have been examined in preclinical and clinical studies; however, these trials have largely failed to demonstrate an improvement in therapeutic efficacy. Therefore, new and innovative strategies, such as the fallback to natural products, the design of peptidomimetics and dual activity ligands emerged as a fourth generation of P-gp inhibitors. The chemistry of P-gp inhibitors, as well as their in vitro, in vivo and clinical trials are discussed, and the most recent advances concerning Pgp modulators are reviewed.

[The 2009 pandemic influenza A (H1N1) virus infection: experience of a paediatric service at a third-level hospital in Lisbon, Portugal]

INTRODUCTION

The 2009 pandemic influenza A (H1N1) (i.e., Pandemic Influenza) is an acute, infectious illness caused by the influenza A (H1N1) 2009 virus. This disease involves respiratory, gastrointestinal and systemic symptoms along with a high incidence occurring at a paediatric age.

OBJECTIVE

To study the epidemiology, approach and complications of Pandemic Influenza in the paediatric population of a third-level hospital in Lisbon, Portugal, between September and December 2009.

MATERIALS AND METHODS

A retrospective study of children who had received the influenza A (H1N1) 2009 virus test by real time reverse transcriptase-polymerase chain reaction (RT-PCR) were included. The following parameters were analysed: number of tests, days of illness, sex, outcome, age, symptoms, hospitalisation and reason for testing. The distribution and test results were compared with the Pandemic Influenza activity in Portugal. Moreover, among the confirmed cases of infection, the need for hospitalisation, risk factors, severity, chest radiography, treatment and complications were also examined.

RESULTS

A total of 351 tests were performed, on average, 2.6 days after initial symptoms, which included 71.8% outpatients and 30% children younger than three years of age. Overall, 54.4% of the tests were positive for the influenza A (H1N1) 2009 virus and the main comorbidities were respiratory and cardiovascular in nature. One hundred ninety-one cases were confirmed by laboratory studies, and 13.6% required hospitalisation, which lasted an average of 2.7 days. In 82.2% of the cases, the severity was mild, with fever and cough as the most frequent symptoms at 91.9% and 93.7%, respectively. Therapy with the antiviral drug, oseltamivir, was implemented in 35.6% of the cases. Additionally, oseltamivir was used in twelve infants younger than one year in age, including a one-month-old infant with no observed side effects.

DISCUSSION

The epidemiological data obtained are consistent with the published national and international studies. The scientific information available and the recommendations of the irectorate-General for Health contributed to the uniformity of the approaches and the successful outcome.

CoReumaPt protocol: the Portuguese cohort of rheumatic diseases

INTRODUCTION

Rheumatic diseases (RD) are conditions with a variety of clinical manifestations and prognosis influenced by several factors. Cohorts and registries have been already established in some countries and have contributed to important knowledge about the disease course and the long-term outcomes of RD. This paper introduces the CoReumaPt project and sets the first step towards the creation of a prospective cohort study including the main RD occurring in the Portuguese population. CoReumaPt will allow outcomes research of chronic RD and the assessment of factors influencing the development and progression of RD. It will also allow to further evaluate the economic impact and the burden of RD in Portugal. CoReumaPt will be linked to Reuma.pt, the National Register of Rheumatic Diseases from the Portuguese Society of Rheumatology.

METHODS

An open cohort will be created, initially composed by the randomly selected population of the crosssectional National Epidemiological Rheumatic Diseases study (EpiReumaPt) and afterwards by other sources, namely through self- and physician's referral. Follow-up with annual self-administered questionnaires will be performed, in order to systematically collect and analyze outcomes of interest, mainly patient-reported outcomes. Data concerning less frequent assessments, such as radiographs and biomarkers, will also be assembled.

CONCLUSIONS

CoReumaPt will be a valuable resource for scientific research and will deliver pivotal information to improve public health policies concerning the prevention and the management of RD in Portugal.

Portuguese guidelines for the use of biological agents in rheumatoid arthritis - October 2011 update

The authors present the revised version of the Portuguese Society of Rheumatology (SPR) guidelines for the treatment of Rheumatoid Arthritis (RA) with biological therapies. In these guidelines the criteria for introduction and maintenance of biological agents are discussed as well as the contraindications and procedures in the case of nonresponders. Biological treatment (with a tumour necrosis factor antagonist, abatacept or tocilizumab) should be considered in RA patients with a disease activity score 28 (DAS 28) equal to or greater than 3.2 despite treatment with at least 20mg-weekly-dose of methotrexate (MTX) for at least 3 months or, if such treatment is not possible, after 3 months of other conventional disease modifying drug or combination therapy. A DAS 28 score between 2.6 and 3.2 with a significant functional or radiological deterioration under treatment with conventional regimens could also constitute an indication for biological treatment. The treatment goal should be remission or, if that is not achievable, at least a low disease activity, defined by a DAS28 lower than 3.2, without significative functional or radiological worsening. The response criteria, at the end of the first 3 months of treatment, are a decrease of at least 0.6 in the DAS28 score. After 6 months of treatment res­ponse criteria is defined as a decrease greater than 1.2 in the DAS28 score. Non-responders, in accordance to the Rheumatologist’s clinical opinion, should try a switch to another biological agent (tumour necrosis factor antagonist, abatacept, rituximab or tocilizumab).

Systemic sclerosis, a rare case

Systemic sclerosis (SS) is a rare severe autoimmune disease involving the connective tissue. The pathophysiology is not clearly understood. It is characterized by a remarkable clinical heterogeneity, and virtually all organs can be affected. Concerning diagnosis, the presence of antinuclear antibodies (ANA) can be found in more than 90% of patients, but the diagnosis is made gathering clinical manifestations, autoimmune panel, nailfold capillaroscopy and in some cases biopsy of the organ involved. The disease course is also weakly understood, although some serological patterns can be distinguished. Current therapeutic options target few aspects of pathologic mechanism and clinical management remains a challenge.The authors presented a rare case of a SS ANA negative, which demonstrates the diagnostic challenge of this disease.

[Practical guide for the use of biological agents in rheumatoid arthritis - December 2011 update]

The authors review the practical aspects of biological therapy use for rheumatoid arthritis patients, commenting safety issues before and after treatment initiation and the best treatment strategies to optimize efficacy.

From a neutrophilic synovial tissue infiltrate to a challenging case of rheumatoid arthritis

The herein report illustrates how a synovial tissue heavily infiltrated by neutrophils in the first weeks of arthritis, can evolve in few months to a synovial infiltration by lymphocytes with a characteristic pattern of rheumatoid arthritis (RA). This observation suggests a critical initial role of neutrophils in RA onset, which is eventually surpassed by the activation of the adaptive immune system. In addition, this patient, despite the absence of rheumatoid factors and anti-cyclic citrullinated peptide antibodies, progressed to a highly destructive and disabling disease, that was only controlled adequately with rituximab, due to the lack of response to methotrexate and serious adverse effects with TNF blockers therapy.

Alterations on peripheral blood B-cell subpopulations in very early arthritis patients

OBJECTIVE

To characterize circulating B-cell subpopulations of arthritis patients with <6 weeks of disease duration.

METHODS

Peripheral blood samples were collected from very early untreated polyarthritis patients, with <6 weeks of disease duration, for flow cytometric evaluation of B-cell subpopulations. Samples from patients who were later diagnosed as RA [very early RA (VERA)] were also collected 4-6 weeks after starting a low dose of prednisone (5-10 mg) and 4 months after reaching the minimum effective dose of MTX. A matched healthy group was used as a control.

RESULTS

VERA patients have a lower percentage of total peripheral blood memory B cells (CD19(+)CD27(+)) and a significant decrease in the frequency of circulating pre-switch memory B cells (CD19(+)IgD(+)CD27(+)) as compared with controls. Therapy with corticosteroids or MTX was unable to restore the normal frequencies of these B-cell subpopulations. A significant decrease in peripheral pre-switch memory B cells is equally observed in other early arthritis patients. Furthermore, no significant differences are found in the frequencies of CD4(+) and CD8(+) T cells in all patient groups.

CONCLUSIONS

In very early polyarthritis patients, there is a reduction in circulating pre-switch memory B cells. The reasons that may account for this effect are still unknown. Short-term corticosteroids and MTX do not seem to have a direct effect on circulating B-cell subpopulations in VERA patients.

Association of IL23R and ERAP1 genes with ankylosing spondylitis in a Portuguese population

OBJECTIVE

Association between ankylosing spondylitis (AS) and two genes, ERAP1 and IL23R, has recently been reported in North American and British populations. The population attributable risk fraction for ERAP1 in this study was 25%, and for IL23R, 9%. Confirmation of these findings to ERAP1 in other ethnic groups has not yet been demonstrated. We sought to test the association between single nucleotide polymorphisms (SNPs) in these genes and susceptibility to AS among a Portuguese population. We also investigated the role of these genes in clinical manifestations of AS, including age of symptom onset, the Bath Ankylosing Spondylitis Disease Activity, Metrology and Functional Indices, and the modified Stoke Ankylosing Spondylitis Spinal Score.

METHODS

The study was conducted on 358 AS cases and 285 ethnically matched Portuguese healthy controls. AS was defined according to the modified New York Criteria. Genotyping of IL23R and ERAP1 allelic variants was carried out with TaqMan allelic discrimination assays. Association analysis was performed using the Cochrane-Armitage and linear regression tests of genotypes as implemented in PLINK for dichotomous and quantitative variables respectively. A meta-analysis for Portuguese and previously published Spanish IL23R data was performed using the StatsDirect Statistical tools, by fixed and random effects models.

RESULTS

A total of 14 nsSNPs markers (8 for IL23R, 5 for ERAP1, 1 for LN-PEP) were analysed. Three markers (2 for IL23R and 1 for ERAP1) showed significant single-locus disease associations, confirming that the association of these genes with AS in the Portuguese population. The strongest associated SNP in IL23R was rs1004819 (OR=1.4, p=0.0049), and in ERAP1 was rs30187 (OR=1.26, p=0.035). The population attributable risk fractions in the Portuguese population for these SNPs are 11% and 9.7% respectively. No association was seen with any SNP in LN-PEP, which flanks ERAP1 and was associated with AS in the British population. No association was seen with clinical manifestations of AS.

CONCLUSION

These results show that IL23R and ERAP1 genes are also associated with susceptibility to AS in the Portuguese population, and that they contribute a significant proportion of the population risk for this disease.