Orbit deformities in craniofacial neurofibromatosis type 1.

BACKGROUND AND PURPOSE: The possible relationship of orbit deformities in neurofibromatosis type 1 (NF1) to plexiform neurofibromas (PNFs) have not been fully elucidated. Our purpose was to review orbital changes in patients with craniofacial NF1. METHODS: We retrospectively reviewed CT and MR imaging abnormalities of the orbit in 31 patients (18 male, 13 female; mean age, 14 years; age range 1-40 years) with craniofacial NF1. RESULTS: Orbital abnormalities were documented in 24 patients. Six had optic nerve gliomas with enlarged optic canals. Twenty had PNFs in the orbit or contiguous to the anterior skull. The posterior orbit was distorted by encroachment from an expanded middle cranial fossa in 13 patients, and 18 had enlargement of the orbital rim. Other changes included focal decalcification or remodeling of orbital walls adjacent to PNFs in 18 patients and enlargement of cranial foramina resulting from tumor infiltration of sensory nerves in 16. These orbital deformities were sometimes progressive and always associated with orbital infiltration by PNFs. CONCLUSION: In our patients with craniofacial neurofibromatosis, bony orbital deformity occurred frequently and always with an optic nerve glioma or orbital PNF. PNFs were associated with orbital-bone changes in four patterns: expansion of the middle cranial fossa into the posterior orbit, enlargement of the orbital rim, bone erosion and decalcification by contiguous tumor, and enlargement of the cranial foramina. Orbital changes support the concept of secondary dysplasia, in which interaction of PNFs with the developing skull is a major component of the multifaceted craniofacial changes possible with NF1.

Inhibition by eicosapentaenoic acid of IL-1beta-induced PGHS-2 expression in human microvascular endothelial cells: involvement of lipoxygenase-derived metabolites and p38 MAPK pathway.

Prostaglandin H synthase 2 (PGHS-2), a highly inducible isoenzyme, is responsible for overproduction of the prostaglandins (PGs) in inflammatory sites. We established that among fish oil polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA), but not docosahexaenoic acid (DHA), greatly decreased interleukin-1beta (IL-1beta)-induced PGHS-2 expression in human pulmonary microvascular endothelial cells (HPMECs). Lipoxygenase products 12 (S)-hydroperoxyeicosapentaenoic acid ((S)-HpEPE), 15 (S)-HpEPE and leukotriene (LT) D5 reproduced similar inhibitory effect, suggesting that they may be the intermediate metabolites responsible for PGHS-2 down-regulation by EPA. Accordingly, the EPA effect is prevented by nordihydroguaiaretic acid (NDGA) and by REV 5901, nonspecific and specific 5-lipoxygenase inhibitors, respectively. Besides, inhibition of cyclooxygenase activity by ibuprofen, indomethacin or aspirin was not able to prevent this effect. Moreover, cyclooxygenase metabolites of EPA (PGs D3, E3 and I3) markedly potentiate IL-1beta-induced PGHS-2 expression, probably by increasing intracellular cAMP levels. Peroxisome proliferator-activated receptors (PPARs) are known to be activated by fatty acids (FAs) such as EPA. We found here that HPMECs express only weak amounts of PPARalpha and PPARgamma whose activation by synthetic agonists, Wy-14,643 and ciglitazone, does not cause any inhibition of IL-1beta-induced PGHS-2 expression. This finding ruled out the involvement of PPARs in the EPA inhibitory effect. In addition, we established that EPA, which failed to inhibit nuclear factor-kappaB (NF-kappaB) activation, suppressed p38 mitogen-activated protein kinase (MAPK) phosphorylation in stimulated HPMECs. Our data demonstrate that EPA, unlike DHA, down-regulates PGHS-2 expression in HPMECs probably through its 5-lipoxygenase-dependent metabolites and advocates a beneficial role for this FA in limiting inflammatory response.

TNF-alpha, inefficient by itself, potentiates IL-1beta-induced PGHS-2 expression in human pulmonary microvascular endothelial cells: requirement of NF-kappaB and p38 MAPK pathways.

1: Prostaglandin H synthase-2 (PGHS-2), is an inducible enzyme involved in various inflammatory responses. We established here that interleukin-1beta (IL-1beta) but not tumour necrosis factor-alpha (TNF-alpha) increased its expression in human pulmonary microvascular endothelial cells (HPMEC). However, associated with IL-1beta, TNF-alpha greatly potentiated this enzyme induction. 2: Although unable to induce PGHS-2 expression by itself, TNF-alpha promoted a similar transcription nuclear factor-kappaB (NF-kappaB) activation to IL-1beta. This effect was more pronounced when cells were co-exposed to both cytokines. HPMEC pre-treatment with MG-132, a proteasome inhibitor, prevented NF-kappaB activation as well as more distal signalling response, indicating that NF-kappaB activation is required but not sufficient for PGHS-2 expression. 3: Both IL-1beta and TNF-alpha failed to activate c-Jun NH2-terminal kinase (JNK). In addition, PD98059, a p42/44 mitogen-activated protein kinase (MAPK) phosphorylation inhibitor, did not decrease PGHS-2 expression. However, SB 203580, a p38 MAPK inhibitor, suppressed PGHS-2 induction by IL-1beta alone or combined with TNF-alpha, demonstrating that p38 MAPK but not p42/44 MAPK or JNK cascades are required for PGHS-2 up-regulation. 4: Finally, TNF-alpha, unlike IL-1beta, was unable to promote p38 MAPK phosphorylation, indicating that the failure of TNF-alpha to induce PGHS-2 expression is linked, at least in part, to its inability to activate p38 MAPK signalling pathway. Altogether, these data enhanced our understanding of PGHS-2 regulation in HPMEC and emphasize the heterogeneity of cellular responses to proinflammatory cytokines.

Reassessment of sphenoid dysplasia associated with neurofibromatosis type 1.

BACKGROUND AND PURPOSE: Sphenoid dysplasia associated with neurofibromatosis type 1 is classically thought to be primarily related to abnormal development of the sphenoid bone. We investigated the possibility that these changes may be progressive. METHODS: We conducted a retrospective review of sphenoid bone changes in all patients with craniofacial neurofibromatosis type 1 who had undergone CT (31 patients) and MR imaging (seven patients) at our facility. A review of repeat images of 20 patients permitted analysis of progressive sphenoid bone changes. RESULTS: Eighteen patients had abnormalities of the sphenoid wings, 13 of whom also had enlargement of the middle cranial fossa compatible with descriptions of classic sphenoid dysplasia. All the patients with sphenoid dysplasia had neurofibromas in the ipsilateral superficial temporal fossa that were often contiguous with a radiologically abnormal temporo-squamosal suture. All except one had tumor infiltration in the deep orbit, contiguous with the sphenoid wings. Four patients had radiologic evidence of progressive sphenoid bone changes over time. CONCLUSION: The origin of sphenoid bone changes may be multifactorial. A modified concept of sphenoid dysplasia is proposed that emphasizes interaction between neurofibromas and sphenoid bone during skull development.

Mycobacterium of an unknown strain causing a primary tumoral process of the orbital roof.

PURPOSE. To report an unidentified species of atypical Mycobacterium as the causative agent of a primary orbital roof infection. METHOD. Review of a case from the King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. RESULTS. The patient had a negative history for eye trauma. Computed tomography (CT) of the brain and right orbit confirmed the presence of soft tissue swelling and erosive changes in the orbital roof bone, with intact globe and external ocular muscles. Biopsy of the lesion showed non-caseating, granulomatous osteomyelitis. Various stains of the sample were negative. Since our institution could not identify the causative organism, a biopsy sample was sent to Bioscientia Laboratory in Germany; the culture grew an atypical Mycobacterium of unknown species. Their sensitivity study showed the organism to be resistant to pyrazinamide, isoniazide and streptomycin, but sensitive to rifampicin, ethambutol, and prothionamide. Systemic checkup and investigation ruled out any other systemic involvement. CONCLUSION. A new species of atypical Mycobacterium was recovered from a primary orbital infection. The infection responded to combined antituberculous therapy.