Long-term absence of porcine endogenous retrovirus infection in chronically immunosuppressed patients after treatment with the porcine cell-based Academic Medical Center bioartificial liver.

BACKGROUND: Clinical use of porcine cell-based bioartificial liver (BAL) support in acute liver failure as bridging therapy for liver transplantation exposes the patient to the risk of transmission of porcine endogenous retroviruses (PERVs) to human. This risk may be enhanced when patients receive liver transplant and are subsequently immunosuppressed. As further follow-up of previously reported patients (Di Nicuolo et al. 2005), an assessment of PERV infection was made in the same patient population pharmacologically immunosuppressed for several years after BAL treatment and in healthcare workers (HCWs) involved in the clinical trial at that time. METHODS: Plasma and peripheral blood mononuclear cells (PBMCs) from eight patients treated with the Academic Medical Center-BAL (AMC-BAL), who survived to transplant, and 13 HCWs, who were involved in the trial, were assessed to detect PERV infection. A novel quantitative real-time polymerase chain reaction assay has been used. RESULTS: Eight patients who received a liver transplant after AMC-BAL treatment are still alive under long-term pharmacological immunosuppression. The current clinical follow-up ranges from 5.6 to 8.7 yr after BAL treatment. A new q-real-time PCR assay has been developed and validated to detect PERV infection. The limit of quantification of PERV DNA was ≥ 5 copies per 1 × 10(5) PBMCs. The linear dynamic range was from 5 × 10(0) to 5 × 10(6) copies. In both patients and HCWs, neither PERV DNA in PBMCs nor PERV RNA in plasma and PBMC samples have been found. CONCLUSION: Up to 8.7 yr after exposure to treatment with porcine liver cell-based BAL, no PERV infection has been found in long-term immunosuppressed patients and in HCWs by a new highly sensitive and specific q-real-time PCR assay.

Wide gene expression profiling of ischemia-reperfusion injury in human liver transplantation.

Ischemia-reperfusion injury (IRI) causes up to 10% of early liver failures in humans and can lead to a higher incidence of acute and chronic rejection. So far, very few studies have investigated wide gene expression profiles associated with the IRI process. The discovery of novel genes activated by IRI might lead to the identification of potential target genes for the prevention or treatment of the injury. In our study, we compared gene expression levels in reperfused livers (RL group) vs. the basal values before retrieval from the donor (basal liver [BL] group) using oligonucleotide array technology. We examined 10 biopsies from 5 livers, analyzing approximately 33,000 genes represented on the Affymetrix HG-U133APlus 2.0 oligonucleotide arrays (Affymetrix, Santa Clara, CA). About 13,000 individual genes were considered expressed in at least 1 condition. A total of 795 genes whose expression is significantly modified by ischemia-reperfusion in human liver transplantation were identified in this study. Some of them are likely to be completely activated by IRI, as they are not expressed in basal livers. The supervised gene expression analysis revealed that at least 12% of the genes involved in the apoptotic process, 12.5% of the genes involved in inflammatory processes, and 22.5% of the genes encoding for heat shock proteins are differentially expressed in RL samples vs. BL samples. Furthermore, IRI induces the upregulation of some genes' coding for adhesion molecules and integrins. In conclusion, we have identified a relevant amount of early genes regulated in the human liver after 7-9 hours of cold ischemia and 2 hours from reperfusion, many of them not having been described before in this process. Their analyses may help us to better understand the pathophysiology of IRI and to characterize potential target genes for the prevention or treatment of the liver injury in order to increase the number of patients that successfully undergo transplantation.

3-Nitropropionic acid increases frataxin expression in human lymphoblasts and in transgenic rat PC12 cells.

Friedreich ataxia (FRDA) is the most common recessive ataxia caused by reduced expression of frataxin, a nuclear encoded mitochondrial protein. In this study we examined the effects of 3-nitropropionic acid (3-NP) on frataxin expression in FRDA patient and control lymphoblasts and in rat pheochromocytoma cell line (PC12) overexpressing human frataxin. Our studies showed an up-regulation of frataxin expression in both FRDA and control lymphoblasts following exposure to 3-NP. In addition, in transgenic frataxin overexpressing cells 3-NP caused an increase of frataxin protein.

Scanning for mutations of the ryanodine receptor (RYR1) gene by denaturing HPLC: detection of three novel malignant hyperthermia alleles.

BACKGROUND: Malignant hyperthermia (MH) is a fatal autosomal dominant pharmacogenetic disorder characterized by skeletal muscle hypertonicity that causes a sudden increase in body temperature after exposure to common anesthetic agents. The disease is genetically heterogeneous, with mutations in the gene encoding the skeletal muscle ryanodine receptor (RYR1) at 19q13.1 accounting for up to 80% of the cases. To date, at least 42 RYR1 mutations have been described that cause MH and/or central core disease. Because the RYR1 gene is huge, containing 106 exons, molecular tests have focused on the regions that are more frequently mutated. Thus the causative defect has been identified in only a fraction of families as linked to chromosome 19q, whereas in others it remains undetected. METHODS: We used denaturing HPLC (DHPLC) to analyze the RYR1 gene. We set up conditions to scan the 27 exons to identify both known and unknown mutations in critical regions of the protein. For each exon, we analyzed members from 52 families with positive in vitro contracture test results, but without preliminary selection by linkage analysis. RESULTS: We identified seven different mutations in 11 MH families. Among them, three were novel MH alleles: Arg44Cys, Arg533Cys, and Val2117Leu. CONCLUSION: Because of its sensitivity and speed, DHPLC could be the method of choice for the detection of unknown mutations in the RYR1 gene.

Identification of a novel transcript of X25, the human gene involved in Friedreich ataxia.

Friedreich ataxia (FRDA) is caused by a GAA triplet expansion in the first intron of the X25 gene. The X25 gene encodes a 210-amino acid protein, frataxin (A isoform). Here, we report the identification of a new transcript of the X25 gene generated by alternative splicing by the use of a second donor splice site in the intron 4. Full-length cDNA transcript sequence revealed an insertion of 8 bp between 4 and 5a exon sequence. This event leads to a frameshift in the mRNA reading frame and introduces a new stop codon at position 589. Therefore, this X25 transcript variant may encode a 196-amino acid protein, the A1 isoform, that structurally differs from the main A isoform of 210 amino acids after residue 160. In all human tissues analyzed, reverse transcription-polymerase chain reaction experiments demonstrated that the A1 isoform was expressed at low levels compared with the predominant A isoform. No difference in A and A1 isoform expression rate was detected between FRDA patients and normal controls. We did not find an A1 like splice variant in rodents.