Pancreatic acinar and islet cell infection by low-dose SV40 administration.

OBJECTIVES: Viral vector uptake into the pancreas is rare. The few viral vectors reported to transduce in vivo pancreatic islets after systemic injection required additional physical measures, such as direct pancreatic injection or hepatic vessel clamping. Because pancreatic islet uptake of the human polyomavirus family member BK virus was previously reported in hamsters after systemic administration, we hypothesized that SV40, a polyomavirus member remarkably similar to BK virus, may also infect the pancreas. METHODS: We injected intravenously a low dose of SV40, unaided by any other physical or chemical means, and evaluated viral uptake by pancreatic islets and pancreatic exocrine tissue via polymerase chain reaction, Western blot, electron microscopy, immunofluorescent microscopy, and protein A-gold immunocytochemistry. RESULTS: Pancreatic uptake of SV40 was comparable to other major organs (ie, liver and spleen). SV40 viral particles were detected in both pancreatic islets and acini. In pancreatic islets, all islet cell types were infected by SV40, albeit the infection rate of glucagon-producing alpha cells surpassed beta- and delta-islet cells. Low-dose SV40 administration was not sufficient to induce heterologous gene expression in the pancreas. CONCLUSIONS: Our study shows that pancreatic islet and acinar cell uptake of SV40 is feasible with a single, low-dose intravenous injection. However, this dose did not result in gene delivery into the murine pancreas.

2756GG genotype of methionine synthase reductase gene is more prevalent in rheumatoid arthritis patients treated with methotrexate and is associated with methotrexate-induced nodulosis.

OBJECTIVE: To investigate the distribution of the A2756G polymorphism of the methionine synthase reductase (MTR) gene in patients with rheumatoid arthritis (RA) treated with methotrexate (MTX) compared with a healthy control group; and to examine the relationships among the A2756G polymorphism, plasma total homocysteine (tHcy), serum folate and vitamin B12 levels, disease activity, and MTX toxicity in patients with RA. METHODS: A cross-sectional study was performed on 86 MTX-treated RA patients, consisting of a clinical interview and physical examination to determine disease activity and MTX-related adverse reactions. Genotype analysis of the MTR gene was performed. Fasting plasma tHcy, serum folate, and vitamin B12 levels were measured. Allele and genotype distributions were compared to a healthy control group. RESULTS: The frequency of the 2756GG genotype (16.3%) in the RA study group was higher than that expected in the general population (3.6%; p < 0.000001). This genotype was associated with MTX-induced accelerated rheumatoid nodulosis (MIARN). No association of disease activity variables or plasma homocysteine with MTR A2756G polymorphisms was observed. The MTR 2756GG genotype, low plasma vitamin B12 levels, and the presence of rheumatoid nodules predicted MIARN. No association of nodulosis with any other indicator of disease activity or medical treatment was found. CONCLUSION: In our population of MTX-treated RA patients the 2756GG genotype of the MTR gene was more common than expected and was associated with MIARN.