The 4G/4G plasminogen activator inhibitor-1 genotype is associated with frequent recurrence of acute otitis media

The association between plasminogen activator inhibitor type-1 and clinical outcome in paediatric sepsis

: Acute phase protein plasminogen activator inhibitor type-1 (PAI-1) is a key element in fibrinolysis inhibition in sepsis-induced disseminated intravascular coagulation (DIC). Elevated PAI-1 level is related to worse outcome in sepsis. The aim of this study was to investigate the relationship between plasma PAI-1 level and clinical outcome in children with sepsis. A total of 35 children with sepsis were enrolled into this prospective study. Plasma PAI-1 was measured on day-1 and day-4. Systemic coagulation profile was measured on day-4. Individuals were followed up until 28 days. The mean PAI-1 from day-1 to day-4 in overt DIC children was not statistically significant. Contrarily, among nonovert DIC individuals, there was a significant difference (P ≤ 0.001) in PAI-1 levels on day-1 compared with day-4 were 95.25 ± 46.57 vs. 60.36 ± 37.31 ng/ml, respectively. Among survivors, mean PAI-1 level on day-1 was statistically higher than PAI-1 level on day-4 (82.47 ± 44.43 vs. 58.39 ± 32.98 ng/ml), P = 0.021. There was no significant difference between PAI-1 levels on day-1 compared with day-4 in nonsurvivors. PAI-1 was correlated to DIC score with r = 0.606 (P ≤ 0.001). PAI-1 levels significantly decreased on day-4 compared with day-1 among nonovert DIC individuals, and not in overt DIC individuals. Changes in PAI-1 levels in nonsurvivors did not differ. PAI-1 level was positively correlated with DIC score.

The transcriptome of a complete episode of acute otitis media

BACKGROUND

Otitis media is the most common disease of childhood, and represents an important health challenge to the 10-15% of children who experience chronic/recurrent middle ear infections. The middle ear undergoes extensive modifications during otitis media, potentially involving changes in the expression of many genes. Expression profiling offers an opportunity to discover novel genes and pathways involved in this common childhood disease. The middle ears of 320 WBxB6 F1 hybrid mice were inoculated with non-typeable Haemophilus influenzae (NTHi) or PBS (sham control). Two independent samples were generated for each time point and condition, from initiation of infection to resolution. RNA was profiled on Affymetrix mouse 430 2.0 whole-genome microarrays.

RESULTS

Approximately 8% of the sampled transcripts defined the signature of acute NTHi-induced otitis media across time. Hierarchical clustering of signal intensities revealed several temporal gene clusters. Network and pathway enrichment analysis of these clusters identified sets of genes involved in activation of the innate immune response, negative regulation of immune response, changes in epithelial and stromal cell markers, and the recruitment/function of neutrophils and macrophages. We also identified key transcriptional regulators related to events in otitis media, which likely determine the expression of these gene clusters. A list of otitis media susceptibility genes, derived from genome-wide association and candidate gene studies, was significantly enriched during the early induction phase and the middle re-modeling phase of otitis but not in the resolution phase. Our results further indicate that positive versus negative regulation of inflammatory processes occur with highly similar kinetics during otitis media, underscoring the importance of anti-inflammatory responses in controlling pathogenesis.

CONCLUSIONS

The results characterize the global gene response during otitis media and identify key signaling and transcription factor networks that control the defense of the middle ear against infection. These networks deserve further attention, as dysregulated immune defense and inflammatory responses may contribute to recurrent or chronic otitis in children.

Immunity genes and susceptibility to otitis media: a comprehensive review

Otitis media (OM) is a middle ear infection associated with inflammation and pain. This disease frequently afflicts humans and is the major cause of hearing loss worldwide. OM continues to be one of the most challenging diseases in the medical field due to its diverse host targets and wide range of clinical manifestations. Substantial morbidity associated with OM is further exacerbated by high frequency of recurrent infections leading to chronic suppurative otitis media (CSOM). Children have greater susceptibility to, and thus, suffer most frequently from OM, which can cause significant deterioration in quality of life. Genetic factors have been demonstrated, in large part by twin and family studies, to be key determinants of OM susceptibility. In this review, we summarize the current knowledge on immunity genes and selected variants that have been associated with predisposition to OM. In particular, polymorphisms in innate immunity and cytokine genes have been strongly linked with the risk of developing OM. Future studies employing state-of-the-art technologies, including next-generation sequencing (NGS), will aid in the identification of novel genes associated with susceptibility to OM. This, in turn, will open up avenues for identifying high-risk individuals and designing novel therapeutic strategies based on precise targeting of these genes.

Current knowledge of the genetics of otitis media

Otitis media is one of the most common childhood infections leading to doctor's visits and a leading cause of antibiotic prescriptions in children. Twin and family studies have confirmed that the predisposition of developing a bacterial middle ear infection is genetically determined. Several case-control studies have been performed to analyze genes involved in inflammatory processes in search of potential associations. Modern genome-wide association approaches that require no prior assumptions of the involvement of a given gene locus in the risk of otitis media are currently being used to identify otitis media genes, and will hopefully give more detailed information on the pathogenesis of childhood otitis media. That information could be used in finding the high-risk patient, in the prevention of the disease, and in the design of new treatments.

C4A deficiency in children and adolescents with recurrent respiratory infections

Increased susceptibility to recurrent viral and bacterial respiratory infections in children and young adults is not well understood. To evaluate the role of complement factor C4 in the defense against respiratory infections, we studied complement factor C4 allotypes C4A and C4B and copy numbers of C4A and C4B genes in 84 children and young adults with recurrent acute otitis media, sinusitis, or pneumonia and in 74 healthy controls. The occurrence of C4A gene deficiency was significantly higher in patients compared with controls (26% vs 14%, p = 0.048). Girls predominated in the group of patients with C4A deficiency (73% girls and 27% boys, p = 0.004). The lectin pathway of complement was more often functionally impaired in patients with C4A deficiency than in patients with no C4A deficiency (41% vs 13%, p = 0.033). Classical and alternative pathways were normal in individuals with C4 null alleles. C4A deficiency is 1 of the minor defects of the innate immunity that may predispose children and young adults to recurrent respiratory infections. C4 gene testing should be added to the list of investigations when the cause for recurrent acute otitis media, maxillary sinusitis, or pneumonia in children and young adults is sought.

Unraveling the genetics of otitis media: from mouse to human and back again

Otitis media (OM) is among the most common illnesses of early childhood, characterised by the presence of inflammation in the middle ear cavity. Acute OM and chronic OM with effusion (COME) affect the majority of children by school age and have heritability estimates of 40-70%. However, the majority of genes underlying this susceptibility are, as yet, unidentified. One method of identifying genes and pathways that may contribute to OM susceptibility is to look at mouse mutants displaying a comparable phenotype. Single-gene mouse mutants with OM have identified a number of genes, namely, Eya4, Tlr4, p73, MyD88, Fas, E2f4, Plg, Fbxo11, and Evi1, as potential and biologically relevant candidates for human disease. Recent studies suggest that this "mouse-to-human" approach is likely to yield relevant data, with significant associations reported between polymorphisms at the FBXO11, TLR4, and PAI1 genes and disease in humans. An association between TP73 and chronic rhinosinusitis has also been reported. In addition, the biobanks of available mouse mutants provide a powerful resource for functional studies of loci identified by future genome-wide association studies of OM in humans. Mouse models of OM therefore are an important component of current approaches attempting to understand the complex genetic susceptibility to OM in humans, and which aim to facilitate the development of preventative and therapeutic interventions for this important and common disease.

Mouse models for human otitis media

Otitis media (OM) remains the most common childhood disease and its annual costs exceed $5 billion. Its potential for permanent hearing impairment also emphasizes the need to better understand and manage this disease. The pathogenesis of OM is multifactorial and includes infectious pathogens, anatomy, immunologic status, genetic predisposition, and environment. Recent progress in mouse model development is helping to elucidate the respective roles of these factors and to significantly contribute toward efforts of OM prevention and control. Genetic predisposition is recognized as an important factor in OM and increasing numbers of mouse models are helping to uncover the potential genetic bases for human OM. Furthermore, the completion of the mouse genome sequence has offered a powerful set of tools for investigating gene function and is generating a rich resource of mouse mutants for studying the genetic factors underlying OM.

Cytokine polymorphisms predict the frequency of otitis media as a complication of rhinovirus and RSV infections in children

Previous studies suggested that the otitis media (OM) complication rate of viral upper respiratory infection (vURI) is conditioned by genes affecting cytokine production. Two hundred and thirty children (114 male; 187 White, 25 Black; aged 1–9.3 years, average = 3.6 ± 1.6 years) were prospectively followed over the typical cold season for cold-like illness and OM. Nasopharyngeal secretion samples collected during cold-like illness and OM were assayed for upper respiratory viruses and buccal samples were assayed for TNFα (−308), IL-10(−1082, −819, −592), IL-6 (−174) and IFN-γ (+874) polymorphisms. Logistic regression was used to identify genotypes that predict OM coincident with RSV and rhinovirus (RV) infection. Of the 157 children with RV detection (79 male; 132 White, 13 Black, 12 Other; aged 3.6 ± 1.5 years), simple logistic regression identified age (B = −0.34, Z = −2.8, P < 0.01, OR = 0.71), IL-6 (B = −0.76, Z = −3.3, P < 0.01, OR = 0.47) and IL-10 (B = 0.49, Z = 2.0, P = 0.05, OR = 1.6) as significant predictors of OM coincidence. A more complex logistic regression model for RV detection that included selected OM risk factors identified these factors as well as the TNFα genotype, OM history, breastfeeding history and daily environment as significant predictors of OM coincidence. Of the 43 children with RSV detection (21 male; 35 White, 5 Black, 3 Other, aged 3.9 ± 1.7 years), logistic regression identified IL-10 (B = 1.05, Z = 2.0, P = 0.05, OR = 2.9) as a significant predictor of OM coincidence. New OM episodes coincident with evidence of RSV and RV infection were significantly more frequent in children with high production IL-10 phenotypes. The low production IL-6 and high production TNFα phenotypes also contributed to OM risk during RV detection. Cytokine polymorphisms may be one of an expectedly large number of genetic factors contributing to the known heritability of OM.