Inter-Subject Variability in OCT1 Activity in 27 Batches of Cryopreserved Human Hepatocytes and Association with OCT1 mRNA Expression and Genotype

Purpose

OCT1/3 (Organic Cation Transporter-1 and -3; SLC22A1/3) are transmembrane proteins localized at the basolateral membrane of hepatocytes. They mediate the uptake of cationic endogenous compounds and/or xenobiotics. The present study was set up to verify whether the previously observed variability in OCT activity in hepatocytes may be explained by inter-individual differences in OCT1/3 mRNA levels or OCT1 genotype.

Methods

Twenty-seven batches of cryopreserved human hepatocytes (male and female, age 24–88 y) were characterized for OCT activity, normalized OCT1/3 mRNA expression, and OCT1 genetic mutation. ASP⁺ (4-[4-(dimethylamino)styryl]-N-methylpyridinium iodide) was used as probe substrate.

Results

ASP⁺ uptake ranged between 75 ± 61 and 2531 ± 202 pmol/(min × million cells). The relative OCT1 and OCT3 mRNA expression ranged between 0.007–0.46 and 0.0002–0.005, respectively. The presence of one or two nonfunctional SLC22A1 alleles was observed in 13 batches and these exhibited significant (p = 0.04) association with OCT1 and OCT3 mRNA expression. However, direct association between genotype and OCT activity could not be established.

Conclusion

mRNA levels and genotype of OCT only partially explain inter-individual variability in OCT-mediated transport. Our findings illustrate the necessity of in vitro transporter activity profiling for better understanding of inter-individual drug disposition behavior.

     

Tissue collection, transport and isolation procedures required to optimize human hepatocyte isolation from waste liver surgical resections. A multilaboratory study.

BACKGROUND: The European Center for Validation of Alternative Methods (ECVAM) has funded a prevalidation study in three laboratories (France, USA and UK) on the use of human hepatocyte cultures to predict cytochrome P-450 induction. AIMS AND METHODS: As first stage of this prevalidation study, the purpose of the present work was to set criteria for optimization and harmonization of hepatocyte isolation from human tissue among laboratories to establish a routine procedure. This was achieved by combining and/or comparing the data generated by the two independent European laboratories (France and UK). RESULTS: The results confirmed that surgical waste material is a valuable source for obtaining high quality hepatocytes under certain pre-, intra- and post-operative conditions: cell yield of viable hepatocytes was not significantly affected by age and sex of patients, nor indications for resection, steatosis or cholestasis. Cold ischeamia up to 5 hours did not influence viable cell yield allowing transport of material. CONCLUSION: The use of biopsy sizes between 50-100 g, cannulation with 2-4 cannulae, digestion with collagenase-containing digestion medium at a flow rate of 25 ml/cannula for 20 minutes, with cut surface being glued in order to reform Glisson's capsule, should optimize the total yield of viable human hepatocytes obtained per preparation of waste liver surgical resections.     

Type 2N von Willebrand disease due to compound heterozygosity for R854Q and a novel R763G mutation at the cleavage site of von Willebrand factor propeptide

Type 2N von Willebrand disease (VWD) is characterized by a markedly decreased affinity of von Willebrand factor (VWF) for factorVIII (FVIII) and is caused by mutations in the D' or D3 domain of mature VWF. We now report a French patient with an atypical 2N VWD phenotype associating FVIII deficiency with plasmaVWF unable to bind FVIII (undetectableVWF:FVIIIB) but with an abnormal multimeric profile. This patient is heterozygous for both the frequent R854Q type 2NVWD mutation and a novel R763G mutation at the cleavage site between VWF propeptide and mature VWF. Four children of the patient displayed moderately decreased VWF:FVIIIB of plasma VWF and were heterozygous for either the R763G or the R854Q mutation. Children with the R763G mutation displayed the same abnormal multimeric profile as their father. Recombinant VWF (rVWF) expression studies performed in COS-7 cells showed that the R763G mutation subtly affects its multimeric profile and dramatically impairs its FVIII binding function. Furthermore, the characteristics of hybrid G763/Q854 rVWF resulting from cotransfection experiments were in agreement with the type 2N VWD diagnosis of the patient. We conclude that R763G is a new type 2N VWD mutation located in the VWF propeptide which alters the proteolytic processing of VWF and consequently its binding to FVIII.     

Role of FOLFIRINOX and chemoradiotherapy in locally advanced and borderline resectable pancreatic adenocarcinoma: update of the AGEO cohort

Background FOLFIRINOX has shown promising results in locally advanced (LAPA) or borderline resectable (BRPA) pancreatic adenocarcinoma. We report here a cohort of patients treated with this regimen from the AGEO group.Methods This is a retrospective multicentre study. We included all consecutive patients with non-pre-treated LAPA or BRPA treated with FOLFIRINOX.Results We included 330 patients (57.9% male, 65.4% <65 years, 96.4% PS <2). Disease was classified as BRPA in 31.1% or LAPA in 68.9%. Objective response rate with FOLFIRINOX was 29.5% and stable disease 51%. Subsequent CRT was performed in 46.4% of patients and 23.9% had curative intent surgery. Resection rates were 42.1% for BRPA and 15.5% for LAPA. Main G3/4 toxicities were fatigue (15%), neutropenia (12%) and neuropathy (G2/3 35%). After a median follow-up of 26.7 months, median OS (mOS) and PFS were 21.4 and 12.4 months, respectively. For patients treated by FOLFIRINOX alone, or FOLFIRINOX followed by CRT, or FOLFIRINOX + /− CRT + surgery, mOS was 16.8 months, 21.8 months and not reached, respectively (p < 0.0001).Conclusions FOLFIRINOX for LAPA and BRPA seems to be effective with a manageable toxicity profile. These promising results in “real-life” patients now have to be confirmed in a Phase 3 randomised trial.Subject terms: Pancreatic cancer, Pancreatic cancer     

Effects of long-term dietary intake of magnesium on oxidative stress, apoptosis and ageing in rat liver

In the present study, we investigated the effect of long-term dietary Mg intake on the rate of oxidative stress, apoptosis and ageing in rat livers. To address this issue, rats were fed diets containing either a moderately deficient (0.15 g Mg/kg diet), a standard (0.8 g Mg/kg diet) or a high (3.2 g Mg/kg diet) Mg dose for two years. It is noteworthy that a higher percentage of animal mortality was observed in the lowest Mg diet, as compared to the other groups. Oxidative stress and antioxidant status were evaluated by measuring different enzyme activities, among which glutathione peroxidase activity was significantly reduced when Mg content was decreased in the diet. Moreover, we obtained an activation of caspase-3 and a higher lipid peroxidation in the Mg-deficient group, as compared to the Mg standard group, while no changes in Mg-supplemented group were observed, in accordance with our previously published data in primary cultures of rat hepatocytes (Martin et al., J Nutr 2003). Telomere shortening was measured in rat livers, as a marker of ageing. We found that telomere length was decreased in old animals, as compared to young animals confirming that telomere shortening correlated well with ageing events. Moreover, in old animals, we obtained a decrease of telomere length in the Mg-deficient group, as compared to the other groups. Taken together, our results show that a long-term chronic Mg deficiency led to oxidative stress, apoptosis and an acceleration of ageing in rat livers.