Role of complement in xenotransplantation

Synthesis of 3H-spiro[benzofuran-2,1′-cyclohexane] derivatives from naturally occurring filifolinol and their classical complement pathway inhibitory activity

Six 3H-spiro[benzofuran-2,1'-cyclohexane] derivatives were synthesized from naturally occurring filifolinol, and their classical complement pathway inhibitory activity was determined. IC(50) values of the most potent compounds were comparable to the activity of the natural complement inhibitor K76-COOH and some synthetic tricyclic analogs of it.

Prevalence of porcine endogenous retrovirus in Chinese pig breeds and in patients treated with a porcine liver cell-based bioreactor

AIM: To determine the prevalence of porcine endogenous retrovirus (PERV) in various pig breeds raised in China including Chinese experimental mini-pigs by PERV-reverse transcriptase (PERV-RT enzyme). Moreover, the potential for infection of PERV was investigated in patients treated with a bioreactor based on porcine liver cells (n = 3).

METHODS: Pig serum, liver and muscle cell-free supernatants were collected from various Chinese pig breeds. Porcine hepatocytes were isolated with a two-step perfusion method. Three patients with acute or chronic liver failure were treated with a bioartificial liver support system (BALSS) for 8-12 h and serum samples were collected from the patients before, immediately after and 30 d after treatment.

RESULTS: The activities of PERV-RT enzyme in pig liver and muscle cell-free supernatants were higher than in normal human controls. PERV-TR enzyme activity did not increase in patients before and after 1 mo of treatment. PERV-RT activities were not significantly different when compared with pre-treatment group (1.544 ± 0.155576), the post-treatment groups (1.501 ± 0.053507, 1.461 ± 0.033808 and 1.6006667 ± 0.01963 for 0, 14 and 30 d post-treatment, respectively, P > 0.05), and normal control group (1.440 ± 1.0641, P > 0.05). RT enzyme activity in Chinese experimental mini-pigs was higher than in normal human control group (1.440 ± 1.0641 U/mL, P < 0.05), and not significantly different (P > 0.05) when compared with the pig breeds except in the muscle supernatants. All the samples including muscle and liver cell supernatants from the Chinese mini-experimental pigs and the four domestic Chinese pig breeds contained PERVs.

CONCLUSION: These results suggest that the risk of PERV infection through BALSS containing porcine liver cells without immunosuppressants may be quite low. Although there were PERVs in Chinese experimental mini-pigs and porcine liver cell culture suspensions, we did not find any evidence of persistent PERV infection in patients treated with this porcine hepatocyte-based bioartificial liver.