Molecular Patterns of MEFV Gene Mutations in Egyptian Patients with Familial Mediterranean Fever: A Retrospective Cohort Study.

BACKGROUND: Familial Mediterranean Fever (FMF) is a hereditary autosomal recessive disease which is mainly seen in the Turks, Armenians, Arabs, and Jews. It is characterized by recurrent episodes of fever, polyserositis, and rash. MEFV gene, encoding pyrin protein, is located on the short arm of chromosome 16. FMF is associated with a broad mutational spectrum in this gene. Certain mutations are more common in particular ethnic groups. To date, different mutations of MEFV were observed in studies carried out in different regions worldwide. However, most of these studies did not extensively investigate the Egyptian population, in spite of the high prevalence of FMF in this geographical region. AIM: To identify the frequency of MEFV gene mutations among the patients who presented with FMF like symptoms and, to characterize the different genetic mutations and their association with increased Amyloid A among Egyptian patients. METHODS: FMF Strip Assay (Vienna Lab Diagnostics, Vienna, Austria) was used. This test is based on reverse hybridization of biotinylated PCR products on immobilized oligonucleotides for mutations and controls in a parallel array of allele-specific oligonucleotides. RESULTS: Among the 1387 patients presenting with signs and symptoms suggestive of FMF, 793 (57.2%) were of undefined mutations, whereas 594 had MEFV gene mutations. 363 patients (26.2%) were heterozygous mutants, 175 patients (12.6%) were compound heterozygous mutants, and 56 patients (4%) were homozygous mutants. The most commonly encountered gene mutations in heterozygous and homozygous groups were E148Q (38.6%), M694I (18.1%), and V726A (15.8%). The most commonly encountered gene mutations in the compound heterozygous groups were E148Q+M694I observed in 20.6% of the patients, followed by M694I+V726A and M6801+V726A found in 18.9% and 11.4 %, respectively. The most commonly encountered gene mutation associated with abdominal pain, fever, and high serum Amyloid A was E148Q allele (37.5%). CONCLUSIONS: Unlike all previous publications, E148Q allele was found to be the most frequent in the studied patients. Moreover, this allele was associated with increased Amyloid A. 793 patients were free of the 12 studied Mediterranean mutations, which implies the necessity to perform future sequencing studies to reveal other mutations.

Cyclic AMP prevents retraction of axon terminals in photoreceptors prepared for transplantation: an in vitro study.

PURPOSE: Cell transplantation has emerged as a possible remedy for degeneration and injury in the central nervous system (CNS). In the retina, photoreceptor transplantation is a potential treatment for retinal degenerative disease. Graft survival has been well documented, but evidence of functional recovery is lacking. A major obstacle to recovery of vision is lack of synapse formation between grafted photoreceptors and host bipolar and horizontal cells. A prior study demonstrated that photoreceptors prepared for transplantation undergo rapid morphologic changes, including retraction of axon terminals toward their cell bodies, away from potential synaptic partners, a phenomenon that may interfere with graft-host synaptic interaction after transplantation. In this study, prevention of retraction of photoreceptor axon terminals was possible by pharmacological intervention. METHODS: Photoreceptor sheets, prepared by vibratome sectioning, and full-thickness retinas, harvested from adult porcine eyes, were maintained in culture and treated with either the cyclic adenosine monophosphate analogue 8-(4-chlorophenylthio)-cyclic 3',5'-adenosine monophosphate (CPT-cAMP), or forskolin, an adenylyl cyclase stimulant, for up to 48 hours. RESULTS: Both CPT-cAMP and forskolin treatments successfully blocked retraction of photoreceptor axon terminals. This effect was not due to cell toxicity and was reversed after removal of treatment, indicating its specificity. CONCLUSIONS: Pharmacological manipulation of photoreceptor axonal plasticity may improve graft-host synaptic interaction after subretinal photoreceptor cell transplantation.

Synaptic plasticity in mammalian photoreceptors prepared as sheets for retinal transplantation.

PURPOSE: To investigate systematically the early morphologic changes in axon terminals of adult mammalian rod and cone photoreceptors prepared as a sheet for subretinal transplantation. METHODS: An in vitro system was designed to maintain adult porcine retinas for up to 48 hours. Photoreceptor sheets, prepared by vibratome sectioning, and full-thickness retinas were cultured at temperatures similar to those in pretransplantation storage (4 degrees C) and after transplantation (37 degrees C). Changes in the outer nuclear and outer plexiform layers were analyzed, using immunohistochemistry, laser scanning confocal microscopy, and image analysis. RESULTS: Morphologic changes were observed in photoreceptor sheets as early as 10 minutes after incubation. The most significant change was the retraction of photoreceptor axons and terminals toward their cell bodies. Retraction was temperature dependent, being exacerbated at 37 degrees C compared with 4 degrees C, at its maximum by 24 hours of culture, and present in sheets obtained from both superior and inferior retina. The cause of this movement was not preparation techniques associated with vibratome sectioning or gelatin removal. Retraction was also present in full-thickness neural retina incubated at 37 degrees C. Reduction in outer nuclear layer cell counts and thickness were also evident in these preparations, primarily in photoreceptor sheets. CONCLUSIONS: Adult photoreceptor sheets, a potential graft preparation for retinal transplantation, show a rapid retraction of axon terminals toward the cell bodies during culture. Although retraction may impede synaptic integration after transplantation, this intrinsic plasticity could be redirected to stimulate graft-host interaction.