P648 Right heart volume overload after surgical correction of atrial septal defect sinus venosus type with partial anomalous pulmonary veins drainage

Discussion

PAPVD is a congenital heart disease characterized by the drainage of one or several pulmonary veins –but not all of them- into the right atrium or systemic veins, which leads to left-to-right shunting. The estimated incidence of this disease ranges between 0.1 and 0.2% of the general population. The right superior pulmonary vein is the most frequently involved and is commonly associated to ASD sinus venosus type. Bilateral anomalous drainage, as occurred in this case, is exceptional.

Furhermore, this case highlights the importance of long-term follow-up in patients with congenital heart disease due to the fact that, even when the disease is considered to be cured, long term complications could appear compromising the prognosis of the patient.

Abstract P648 Figure. Unusual PAPVD

Recurrent noncoding U1 snRNA mutations drive cryptic splicing in SHH medulloblastoma

Recurrent somatic single nucleotide variants (SNVs) in cancer are largely confined to protein coding genes, and are rare in most pediatric cancers^1–3. We report highly recurrent hotspot mutations of U1 spliceosomal small nuclear RNAs (snRNAs) in ~50% of Sonic Hedgehog medulloblastomas (Shh-MB), which were not present across other medulloblastoma subgroups. This U1-snRNA hotspot mutation (r.3a>g), was identified in <0.1% of 2,442 cancers across 36 other tumor types. Largely absent from infant Shh-MB, the mutation occurs in 97% of adults (Shhδ), and 25% of adolescents (Shhα). The U1-snRNA mutation occurs in the 5′ splice site binding region, and snRNA mutant tumors have significantly disrupted RNA splicing with an excess of 5′ cryptic splicing events. Mutant U1-snRNA mediated alternative splicing inactivates tumor suppressor genes (PTCH1), and activates oncogenes (GLI2, CCND2), represents a novel target for therapy, and constitutes a highly recurrent and tissue-specific mutation of a non-protein coding gene in cancer.

Human beta-defensin-1 and -2 and matrix metalloproteinase-25 and -26 expression in chronic and aggressive periodontitis and in peri-implantitis

OBJECTIVE

Aberrant matrix metalloproteinase (MMP) and human beta-defensin (HBD) functions have been found in inflammatory diseases. The objectives of this study were to investigate the immunolocalisation, mRNA expression and molecular forms of MMP-25, MMP-26, HBD-1 and HBD-2 in chronic and aggressive periodontitis and in peri-implantitis. The expression of MMP-25 by cultured human plasmacytoma cells and macrophages, and the effects of MMP-26 and Porphyromonas gingivalis trypsin-like proteinase on HBD-1 and -2 were also studied.

DESIGN

Immunohistochemistry, immunofluorescent analysis, reverse transcriptase polymerase chain reaction and immunoblotting were used to assess localisation, mRNA expression and molecular forms of MMP-25, MMP-26, HBD-1 and HBD-2. HBD degradation by MMP-26 and P. gingivalis proteinase was studied by sodium dodecyl sulphate-polyacrylamide gel electrophoresis.

RESULTS

MMP-25 was present in plasma cells and polymorphonuclear leucocytes, and MMP-26 was present in oral and sulcular basement membrane zones. HBD-1 was distributed perivasculary in gingival connective tissue and in oral and sulcular epithelium, and HBD-2 was found to a lesser extent in the perivascular space. Low MMP-25, MMP-26, HBD-1 and HBD-2 mRNA expression was found. Immunoblot revealed 29-57-kDa MMP-25 in myeloma cell lysates, but not in macrophages, and partly activated MMP-25 and -26 in diseased gingival crevicular fluid and peri-implant sulcular fluid. P. gingivalis trypsin-like proteinase degraded HBD-1 and -2.

CONCLUSIONS

Both MMP-25 and -26 were expressed more strongly in extensively inflamed gingiva compared with healthy gingiva. The expression of HBD-1 was stronger than that of HBD-2 in periodontitis and peri-implantitis. De-novo expression of MMP-25 and -26 is associated with periodontal and peri-implant inflammation. Furthermore, P. gingivalis trypsin-like proteinase, but not MMP-26, can degrade HBD-1 and -2, which could lead to a weakened innate immune response.

Collagenase-2 (MMP-8) and matrilysin-2 (MMP-26) expression in human wounds of different etiologies

Wound healing involves highly controlled events including reepithelialization, neoangiogenesis, and reformation of the stromal compartment. Matrix metalloproteinases (MMPs) are a family of neutral zinc-dependent endopeptidases known to be essential for the wound-healing process. MMP-8 (collagenase-2) is a neutrophil-derived highly effective type I collagenase, recently indicated to be important for acute wound healing. MMP-26 is a more recent and less well-studied member of the MMP family. Our aim was to study the expression of MMP-8 and MMP-26 in human cutaneous wound repair and chronic wounds using histological methods and cell culture. MMP-8 expression was associated with epithelial cells, neutrophils, and other inflammatory cells in chronic human wounds. MMP-26 was prominently expressed in the extracellular compartment of most chronic wounds in close vicinity to the basement membrane area. MMP-26 was also expressed in acute day 1 wounds with declining expression thereafter. In vitro wound experiments showed that both MMP-8 and MMP-26 were expressed by migrating human mucosal keratinocytes. Inhibiting MMP-26 resulted in aberrant keratinocyte migration and proliferation. We conclude that MMP-8 and MMP-26 are differentially expressed in acute and chronic wounds.

Interleukin-6-induced plasminogen gene expression in murine hepatocytes is mediated by transcription factor CCAAT/enhancer binding protein beta (C/EBPbeta)

An emerging area of research has demonstrated that plasminogen functions in the acute-phase response to tissue injury, neoplastic growth or infection. We have previously shown that the acute-phase mediator, interleukin (IL)-6, increases circulating plasminogen levels via upregulation of plasminogen promoter activity. We also identified a putative IL-6 responsive element (nt -791 to -783; IL6-RE) in the plasminogen gene that is required for maximal stimulation of promoter activity by IL-6. For the present study, we investigated the transcription factors and signaling pathway mediating the response of the plasminogen gene to IL-6. In electrophoretic mobility shift assays (EMSAs), a radiolabeled oligonucleotide IL6-RE probe formed specific complexes with nuclear proteins from untreated hepatocytic cells. The extent of complex formation was markedly increased using nuclear proteins from IL-6-treated cells. Complex formation was abolished by an oligonucleotide with the consensus CCAAT/enhancer binding protein (C/EBP) sequence. Furthermore, complexes were supershifted by antibodies to C/EBPbeta. Treatment of Hepa 1-6 cells with the mitogen-activated protein kinase (MAPK) inhibitor, PD-98059, inhibited IL-6-stimulated plasminogen promoter activity. These results suggest that transcription factor C/EBPbeta and the MAPK pathway play key roles in the response of the plasminogen gene to IL-6, thus elucidating a major mechanism by which the plasminogen system is upregulated to perform its crucial functions in the acute-phase response.