Growth-related micromorphological characteristics of the porcine femoral artery.

BACKGROUND: In cardiovascular research small pigs breeds like Göttingen® minipigs (GM) are established animal models, but systematic data about the micromorphology of the GM vasculature at different ages are scarce. OBJECTIVE: The study was aimed at gaining knowledge about the micromorphology of the femoral artery (FA) from German Landrace pigs (DL) and GM during the period of growth over a body weight range of 10-40 kg. METHODS: FA samples from DL aged two or three months were compared to GM ones, aged 18 or 40 months using transmitted light microscopy. RESULTS: All FA samples showed typical characteristics of muscular arteries. Growth was associated with increased vessel wall thickness. In the GM this resulted in a slight decrease of the luminal diameter (LD), while in the DL pigs, an increase of the LD and smooth muscle cell content (10%) with decreased elastic fiber content (10%) has been detected. In contrast, within the 22 months lasting growth period of the GM, the tunica media content of smooth muscle cells and elastic fibers remained stable. CONCLUSIONS: FA maturation strongly depends on the pig breed and age. It can be different from what is described in humans.

Telemonitoring to improve nutritional status in community-dwelling elderly: design and methods for process and effect evaluation of a non-randomized controlled trial.

BACKGROUND: A good nutritional status is key for maintaining health and quality of life in older adults. In the Netherlands, 11 to 35% of the community-dwelling elderly are undernourished. Undernutrition or the risk of it should be signalled as soon as possible to be able to intervene at an early stage. However, in the context of an ageing population health care resources are scarce, evoking interest in health enabling technologies such as telemonitoring. This article describes the design of an intervention study focussing at telemonitoring and improving nutritional status of community-dwelling elderly. METHODS: The PhysioDom Home Dietary Intake Monitoring intervention was evaluated using a parallel arm pre-test post-test design including 215 Dutch community-dwelling elderly aged > 65 years. The six-month intervention included nutritional telemonitoring, television messages, and dietary advice by a nurse or a dietician. The control group received usual care. Measurements were performed at baseline, after 4.5 months, and at the end of the study, and included the primary outcome nutritional status and secondary outcomes behavioural determinants, diet quality, appetite, body weight, physical activity, physical functioning, and quality of life. Furthermore, a process evaluation was conducted to provide insight into intervention delivery, feasibility, and acceptability. DISCUSSION: This study will improve insight into feasibility and effectiveness of telemonitoring of nutritional parameters in community-dwelling elderly. This will provide relevant insights for health care professionals, researchers, and policy makers. TRIAL REGISTRATION: The study was retrospectively registered at Clinical-Trials.gov (identifier NCT03240094 ) since August 3, 2017.

Determinants of lifestyle behavior change to prevent type 2 diabetes in high-risk individuals.

BACKGROUND: Although there are many effective lifestyle interventions for type 2 diabetes (T2DM) prevention, insight into effective intervention pathways, especially of long-term interventions, is often lacking. This study aims to provide insight into the effective intervention pathways of the SLIMMER diabetes prevention intervention using mediation analyses. METHODS: In total, 240 participants at increased risk of T2DM were included in the analyses over 18 months. The intervention was a combined lifestyle intervention with a dietary and a physical activity (PA) component. The primary and secondary outcomes were change in fasting insulin (pmol/L) and change in body weight (kg) after 18 months, respectively. Firstly, in a multiple mediator model, we investigated whether significant changes in these outcomes were mediated by changes in dietary and PA behavior. Secondly, in multiple single mediator models, we investigated whether changes in dietary and PA behavior were mediated by changes in behavioral determinants and the participants' psychological profile. The mediation analyses used linear regression models, where significance of indirect effects was calculated with bootstrapping. RESULTS: The effect of the intervention on decreased fasting insulin was 40% mediated by change in dietary and PA behavior, where dietary behavior was an independent mediator of the association (34%). The effect of the intervention on decreased body weight was 20% mediated by change in dietary and PA behavior, where PA behavior was an independent mediator (17%). The intervention significantly changed intake of fruit, fat from bread spread, and fiber from bread. Change in fruit intake was mediated by change in action control (combination of consciousness, self-control, and effort), motivation, self-efficacy, intention, and skills. Change in fat intake was mediated by change in action control and psychological profile. No mediators could be identified for change in fiber intake. The change in PA behavior was mediated by change in action control, motivation, and psychological profile. CONCLUSION: The effect of the SLIMMER intervention on fasting insulin and body weight was mediated by changes in dietary and PA behavior, in distinct ways. These results indicate that changing dietary as well as PA behavior is important in T2DM prevention.

Effect and maintenance of the SLIMMER diabetes prevention lifestyle intervention in Dutch primary healthcare: a randomised controlled trial.

BACKGROUND/OBJECTIVES: To assess the effectiveness of the SLIMMER combined dietary and physical activity lifestyle intervention on clinical and metabolic risk factors, dietary intake, physical activity, and quality of life after 12 months, and to investigate whether effects sustained six months after the active intervention period ended. SUBJECTS/METHODS: SLIMMER was a randomised controlled intervention, implemented in Dutch primary healthcare. In total, 316 subjects aged 40-70 years with increased risk of type 2 diabetes were randomly allocated to the intervention group (10-month dietary and physical activity programme) or the control group (usual healthcare). All subjects underwent an oral glucose tolerance test and physical examination, and filled in questionnaires. Identical examinations were performed at baseline and after 12 and 18 months. Primary outcome was fasting insulin. RESULTS: The intervention group showed significantly greater improvements in anthropometry and glucose metabolism. After 12 and 18 months, differences between intervention and control group were -2.7 kg (95% confidence interval (CI): -3.7; -1.7) and -2.5 kg (95% CI: -3.6; -1.4) for weight, and -12.1 pmol l-1 (95% CI: -19.6; -4.6) and -8.0 pmol l-1 (95% CI: -14.7; -0.53) for fasting insulin. Furthermore, dietary intake, physical activity, and quality of life improved significantly more in the intervention group than in the control group. CONCLUSIONS: The Dutch SLIMMER lifestyle intervention is effective in the short and long term in improving clinical and metabolic risk factors, dietary intake, physical activity, and quality of life in subjects at high risk of diabetes.

Variability in hepatic expression of organic anion transporter 7/SLC22A9, a novel pravastatin uptake transporter: impact of genetic and regulatory factors.

Human organic anion transporter 7 (OAT7, SLC22A9) is a hepatic transport protein poorly characterized so far. We therefore sought to identify novel OAT7 substrates and factors contributing to variable hepatic OAT7 expression. Using OAT7-expressing cells, pravastatin was identified as a substrate. Hepatic SLC22A9/OAT7 mRNA and protein expression varied 28-fold and 15-fold, respectively, in 126 Caucasian liver samples. Twenty-four variants in SLC22A9 were genotyped, including three rare missense variants (rs377211288, rs61742518, rs146027075), which occurred only heterozygously. No variant significantly affected hepatic SLC22A9/OAT7 expression. The three missense variants, however, showed functional consequences when expressed in vitro. Hepatic nuclear factor 4-alpha (HNF4α) emerged as a major transcriptional regulator of SLC22A9 by a series of in silico and in vitro analyses. In conclusion, pravastatin is the first identified OAT7 drug substrate. Substantial inter-individual variability in hepatic OAT7 expression, majorly driven by HNF4α, may contribute to pravastatin drug disposition and might affect response.The Pharmacogenomics Journal advance online publication, 4 August 2015; doi:10.1038/tpj.2015.55.

Functional characterization of common protein variants in the efflux transporter ABCC11 and identification of T546M as functionally damaging variant.

Multidrug resistance protein 8 (ABCC11) is an efflux transporter for anionic lipophilic compounds, conferring resistance to antiviral and anticancer agents like 5-fluorouracil (5-FU). ABCC11 missense variants may contribute to variability in drug response but functional consequences, except for the 'earwax variant' c.538G>A, are unknown. Using the 'Screen and Insert' technology, we generated human embryonic kidney 293 cells stably expressing ABCC11 missense variants frequently occurring in different ethnic populations: c.57G>A, c.538G>A, c.950C>A, c.1637C>T, c.1942G>A, c.4032A>G. A series of in silico prediction analyses and in vitro plasma membrane vesicle uptake, immunoblotting and immunolocalization experiments were undertaken to investigate functional consequences. We identified c.1637C>T (T546M), previously associated with 5-FU-related toxicity, as a novel functionally damaging ABCC11 variant exhibiting markedly reduced transport function of 5-FdUMP, the active cytotoxic metabolite of 5-FU. Detailed analysis of 14 subpopulations revealed highest allele frequencies of c.1637C>T in Europeans and Americans (up to 11%) compared with Africans and Asians (up to 3%).

Stratified medicine for the use of antidiabetic medication in treatment of type II diabetes and cancer: where do we go from here?

At present, the global diabetes epidemic is affecting 347 million individuals, 90% of whom are diagnosed with type II diabetes mellitus (T2DM). T2DM is commonly treated with more than one type of therapy, including oral antidiabetic drugs (OADs) and agents used in the treatment of diabetic complications. Several pharmacological classes of OADs are currently available for the treatment of T2DM, of which insulin secretagogues (i.e. sulphonylureas and meglitinides), insulin sensitizers [thiazolidinediones (TZDs)] and biguanides are the most commonly prescribed. Although many of these OADs have been used for more than half a century in the treatment of T2DM, the pharmacogenomic characteristics of these compounds have only recently been investigated, primarily in retrospective studies. Recent advances in pharmacogenomics have led to the identification of polymorphisms that affect the expression and function of drug-metabolizing enzymes and drug transporters, as well as drug targets and receptors. These polymorphisms have been shown to affect the therapeutic response to and side effects associated with OADs. The aim of this review was to provide an up-to-date summary of some of the pharmacogenomic data obtained from studies of T2DM treatment, with a focus on polymorphisms in genes affecting pharmacokinetics, pharmacodynamics and treatment outcome of the most commonly prescribed OADs. In addition, the implications of pharmacogenomics in the use of the OAD metformin in cancer will be briefly discussed. Finally, we will focus on recent advances in novel 'omics' technologies and discuss how these might aid in the personalized management of T2DM.

Human pregnane X receptor genotype of the donor but not of the recipient is a risk factor for delayed graft function after renal transplantation.

Delayed graft function (DGF) is an important complication in renal transplantation, contributing significantly to decrease in long-term allograft survival. In addition to donor- and recipient-related risk factors such as immunosuppression, altered renal excretion of xenobiotics by membrane transporters may influence DGF. Using DNA samples from recipients and donors, we assessed the impact on DGF of genetic variants in P-glycoprotein (ABCB1), multidrug resistance protein 2 (ABCC2), and the nuclear pregnane X receptor (PXR/NR1I2), which regulates the transcription of enzymes and transporters. In our local cohort of renal transplant recipients (n = 178), DGF occurred in 27.5%. The PXR 8055TT genotype of the donor only (not of the recipient) was significantly associated with an increased risk for DGF. This finding emerged from univariate as well as multivariate logistic regression analysis including 16 nongenetic factors and held true after correction for multiple testing. Our findings provide the first evidence that PXR may be associated with risk of DGF, independent of previously identified risk factors.

Serum micronutrient concentrations and childhood asthma: the PIAMA birth cohort study.

BACKGROUND: Research suggests an influence of micronutrients on childhood asthma. So far, evidence mainly originates from cross-sectional studies using nutrient intake data, which is not an accurate measure of nutrient status. This study aimed to investigate the cross-sectional and prospective associations between serum concentrations of magnesium, vitamin D, selenium, and zinc and prevalence of (severe) asthma, atopy, and bronchial hyperresponsiveness (BHR) in childhood. METHODS: In the Prevention and Incidence of Asthma and Mite Allergy birth cohort study, serum nutrient concentrations were available for a 4-yr-old subgroup (n = 372) and for a different 8-yr-old subgroup (n = 328). Yearly questionnaires inquired about asthma prevalence until 8 yr of age. Allergic sensitization was measured at 4 and 8 yr of age; BHR was measured at 8 yr of age. Data were analyzed with logistic regression and generalized estimating equations models. RESULTS: There was a consistent (non-significant) inverse association between serum magnesium concentrations and asthma prevalence. Serum vitamin D concentrations measured at age 4 were inversely associated with asthma at ages 4-8 [e.g., cross-sectional association between vitamin D tertile 3 vs. 1 and severe asthma: odds ratio (OR): 0.49, 95% confidence interval (CI): 0.25-0.95], whereas vitamin D measured at age 8 was positively associated with asthma at age 8 (e.g., cross-sectional association between vitamin D tertile 3 vs. 1 and severe asthma: OR: 2.14, 95% CI: 0.67-6.82). CONCLUSIONS: Our study contributes to the evidence that children with higher serum magnesium concentrations are less likely to have asthma. The associations between serum vitamin D concentrations and asthma were age-dependent.

Positive and negative experiences of social support and long-term mortality among middle-aged Dutch people.

This study investigated the relation between positive and negative experiences of social support and mortality in a population-based sample. Data were derived from Dutch men and women aged 20-59 years who participated in the Doetinchem Cohort Study in 1987-1991. Social support was measured at baseline and after 5 years of follow-up by using the Social Experiences Checklist indicating positive (n = 11,163) and negative (n = 11,161) experiences of support. Mortality data were obtained from 1987 until 2008. Cox proportional hazards regression models, adjusted for age and sex, showed that low positive experiences of support at baseline were associated with an increased mortality risk after, on average, 19 years of follow-up (hazard ratio = 1.26, 95% confidence interval: 1.04, 1.52). Even after additional adjustment for socioeconomic factors, lifestyle factors, and indicators of health status, the increased mortality risk remained statistically significant (hazard ratio = 1.23, 95% confidence interval: 1.01, 1.49). For participants with repeated measurements of social support at 5-year intervals, a stable low level of positive experiences of social support was associated with a stronger increase in age- and sex-adjusted mortality risk (hazard ratio = 1.57, 95% confidence interval: 1.03, 2.39). Negative experiences of social support were not related to mortality.

Characterization of different groups of elderly according to social engagement activity patterns.

OBJECTIVE: The aim of this research was to segment older people in subgroups with similar social engagement activity patterns in order to better target public health interventions. DESIGN: Cross-sectional data, collected in 2005 by Dutch community health services (response 79%), from 22026 independently living elderly aged 65 or older were used. Cluster analysis was performed to derive subgroups with common social engagement activity patterns, which were compared for their self-perceived health, mental health, physical health, and loneliness. RESULTS: Among the independently living older people, five subgroups were identified with different patterns of social engagement activities: less social engaged elderly, less social engaged caregivers, social engaged caregivers, leisure engaged elderly, and productive engaged elderly. The subgroups differed significantly in social engagement activities, socio-demographics, and health (p < 0.001). The groups with the highest relative numbers of older people who were frequently engaged in leisure and productive-related activities, also included relatively more elderly with a good self-perceived health (85.8% versus 58.8%), mental health (91.3% versus 74.6%), physical health (97.7% versus 73.0%), and elderly who were not lonely (70.0% versus 52.0%) when compared to the least healthy subgroup. CONCLUSION: Older people could be segmented in subgroups based on similar social engagement patterns. Groups with elderly who were less socially engaged demonstrate to be possible target groups for public health interventions, given the relatively high shares of unhealthy older people among them.

Skipping breakfast, alcohol consumption and physical inactivity as risk factors for overweight and obesity in adolescents: results of the E-MOVO project.

OBJECTIVE/BACKGROUND: To investigate the association between skipping breakfast, alcohol consumption and physical inactivity with overweight and obesity in adolescents. The design comprises cross-sectional electronic health survey (E-MOVO). SUBJECTS/METHODS: Over 35 000 Dutch adolescents in grade 2 (13-14 years of age) and grade 4 (15-16 years of age) of secondary educational schools were recruited by seven community health services. Analyses were performed on 25 176 adolescents. Body mass index was calculated from self-reported body weight and height. Frequency of skipping breakfast per week, amount of alcoholic drinks consumed per occasion, and numbers of physical active days per week were considered as determinants for overweight and obesity. RESULTS: In grade 2, adjusted odds ratios for the association with overweight were 2.17 (95% CI: 1.66-2.85) for skipping breakfast, 1.86 (1.36-2.55) for alcohol consumption and 1.73 (1.19-2.51) for physical inactivity. Statistically significant associations with overweight were also found in grade 4. In grade 2, dose-response relations (P for trend <0.05) were present between all risk factors and overweight. In a multivariate model containing all risk factors, breakfast skipping showed the strongest relation with overweight (OR 1.68, 95% CI 1.43-1.97 for grade 2, OR 1.32 95% CI 1.14-1.54 for grade 4) and obesity. CONCLUSIONS: Skipping breakfast, alcohol consumption and physical inactivity were associated with overweight in second and fourth grade adolescents. The associations were strongest for younger adolescents. The most important risk factor for overweight and obesity was skipping breakfast.

Human multidrug resistance protein 8 (MRP8/ABCC11), an apical efflux pump for steroid sulfates, is an axonal protein of the CNS and peripheral nervous system.

Dehydroepiandrosterone 3-sulfate and other neurosteroids are synthesized in the CNS and peripheral nervous system where they may modulate neuronal excitability by interacting with ligand-gated ion channels. For this modulatory activity, neurosteroids have to be locally released from either neurons or glial cells. We here identify the integral membrane protein ABCC11 (multidrug resistance protein 8) as an ATP-dependent efflux pump for steroid sulfates, including dehydroepiandrosterone 3-sulfate, and localize it to axons of the human CNS and peripheral nervous system. ABCC11 mRNA was detected in human brain by real-time polymerase chain reaction. Antibodies raised against ABCC11 served to detect the protein in brain by immunoblotting and immunofluorescence microscopy. ABCC11 was preferentially found in the white matter of the brain and co-localized with neurofilaments indicating that it is an axonal protein. Additionally, ABCC11 was localized to axons of the peripheral nervous system. For functional studies, ABCC11 was expressed in polarized Madin-Darby canine kidney cells where it was sorted to the apical membrane. This apical sorting is in accordance with the localization of ABCC11 to the axonal membrane of neurons. Inside-out plasma membrane vesicles containing recombinant ABCC11 mediated ATP-dependent transport of dehydroepiandrosterone 3-sulfate with a Km value of 21 microM. This transport function together with the localization of the ABCC11 protein in vicinity to GABAA receptors is consistent with a role of ABCC11 in dehydroepiandrosterone 3-sulfate release from neurons to sites of dehydroepiandrosterone 3-sulfate-mediated receptor modulation. Our findings may provide a basis for the characterization of mutations in the human ABCC11 gene and their linkage with neurological disorders.

Expression and immunolocalization of the multidrug resistance proteins, MRP1-MRP6 (ABCC1-ABCC6), in human brain.

Multidrug resistance proteins (MRPs, symbol ABCC) are membrane glycoproteins that mediate the ATP-dependent export of organic anions, including cytotoxic and antiviral drugs, from cells. To identify MRP family members possibly involved in the intrinsic resistance of human brain to cytotoxic and antiviral drugs, we analyzed the expression and localization of MRP1-MRP6 in rapidly frozen perilesional samples of several regions of adult human brain obtained during neurosurgery. Quantitative polymerase chain reaction analysis showed expression of MRP1, MRP2, MRP3, MRP4, and MRP5 mRNA, whereas MRP6 mRNA was below detectability. However, immunofluorescence microscopy of cryosections from human brain showed no reactivity for the MRP2 or MRP3 proteins. The proteins MRP1, MRP4, and MRP5 were clearly localized by confocal laser scanning microscopy to the luminal side of brain capillary endothelial cells. The MRP4 and MRP5 proteins were also detected in astrocytes of the subcortical white matter. Notably, MRP5 protein was present in pyramidal neurons. MRP proteins may, thus, contribute to the cellular efflux of endogenous anionic glutathione or glucuronate conjugates (substrates for MRP1), cyclic nucleotides (substrates for MRP4 and MRP5), or glutathione (co-substrate for MRP1 and MRP4); in addition, they may play an important role in the resistance of the brain to several cytotoxic and antiviral drugs.

Gender, cohort and geographical differences in 10-year mortality in elderly people living in 12 European towns.

BACKGROUND: In 1988/89, 2586 randomly selected elderly of both sexes born between 1913 and 1918 and living in 19 centres of 12 European countries participated in the SENECA Study on Nutrition and the Elderly in Europe. Differences in nutritional and health status as well in lifestyle factors, namely dietary habits, between the elderly living in the several centres were observed. OBJECTIVE: To study gender, cohort and geographical differences in 10-year mortality in elderly people from the SENECA Study. DESIGN: Longitudinal study. Information on vital status of the elderly people who participated in the baseline study performed in 1988/89 was obtained by standardized procedures in 1999, until 30 April. RESULTS: In all centres, men had higher mortality rates than women. A cohort effect in mortality is observed, particularly in men. A geographical pattern in mortality also more evident in men is shown. In fact, elderly men living in Eastern Europe, represented by the Polish centre, had the highest average hazard rate, 108, while those living in Southern Europe, including the French, the Swiss, the Italian, the Spanish and the Portuguese centres, had the lowest average hazard rates, ranging from 52 in Betanzos/Spain to 67 in the two French towns. Finally, those living in Northern Europe, represented by the Danish, the Dutch and the Belgian centres had intermediate values, from 68 in Roskilde/ Denmark to 85 in Culemborg/the Netherlands. Kaplan-Meier survival curves confirmed the gender, cohort and geographical differences in survival (log-rank test P 0.0001). CONCLUSION: The gender and geographical differences in mortality observed in elderly people living in different regions of Europe put in evidence the potential for increasing the life expectancy in Europe through intervention programs tackling the lifestyle and socio-economic factors behind those differences.

Expression of the multidrug resistance proteins MRP2 and MRP3 in human hepatocellular carcinoma.

Treatment of hepatocellular carcinoma (HCC) by chemotherapy is often impeded by the intrinsic multidrug resistance (MDR) of this frequent primary cancer of the liver. The MDR phenotype can be caused by ATP-dependent export of chemotherapeutic drugs across the plasma membrane being mediated by transporters of the MDR P-glycoprotein family or of the multidrug resistance protein (MRP) family. To elucidate the role of MRP family members in HCC, we analyzed the expression and subcellular localization of MRP1 (ABCC1), MRP2 (ABCC2) and MRP3 (ABCC3); all 3 isoforms have been shown to confer resistance to chemotherapeutic drugs. Semiquantitative RT-PCR demonstrated that MRP2 and MRP3 mRNA expression in HCC was at least 10-fold higher than MRP1 mRNA expression. MRP2 immunostaining was observed in 87% (33/38) of HCC samples. MRP2 was localized in the plasma membrane in a polarized fashion, either in trabecular structures resembling the canalicular membrane or in the luminal membrane when cells had a pseudoglandular arrangement. MRP3 was detected in all samples examined (9/9) by RT-PCR and by immunofluorescence microscopy. MRP3 was localized to the basolateral membrane of carcinoma cells. Double-label immunofluorescence microscopy with antibodies specific for MRP2 or MRP3 indicated that carcinoma cells expressed both MRP isoforms simultaneously. When MRP1 was detected by immunofluorescence microscopy, it was localized on the intracellular membranes of carcinoma cells. Thus, plasma membrane expression of MRP2 and MRP3, but not of MRP1, can contribute to the MDR phenotype of HCC.

Evaluation of dietary quality in relationship to nutritional and lifestyle factors in elderly people of the US Framingham Heart Study and the European SENECA study.

OBJECTIVE: To evaluate dietary quality of European and American elderly subjects using different derivatives of dietary patterns (dietary scores and clusters) and to investigate the relationship of these approaches to nutritional and lifestyle factors. DESIGN: Data from the cross-sectional SENECA baseline study and Framingham Heart Study (original cohort and offspring) were used for data analysis. Food intake data were summarised into dietary clusters and into dietary scores (Healthy Diet Indicator and Mediterranean Diet Score). These measures of dietary quality were then tested for associations with lifestyle factors and measures of nutritional status. SUBJECTS/SETTING: The study population, aged 70-77 y, consisted of 828 subjects from Framingham, MA (USA) and 1282 subjects from the following European centres: Hamme, Belgium; Roskilde, Denmark; Padua, Italy; Culemborg, The Netherlands; Vila Franca de Xira, Portugal; Betanzos, Spain; and Yverdon, Burgdorf and Bellinzona, Switzerland. RESULTS: Dietary intake varied widely across the European and American research centres. In general, Southern European centres and Framingham had higher mean diet scores, indicating a higher dietary quality, than Northern European centres (MD-scores: 4.2-4.4 vs 2.7-3.5). Cluster analysis identified the following five dietary patterns characterised by: (1) sugar and sugar products; (2) fish and grain; (3) meat, eggs and fat; (4) milk and fruit; and (5) alcohol intake. The meat, eggs and fat pattern had significantly lower average dietary quality, as measured with all three diet scores than all other groups except the alcohol group. The fish and grain group had significantly better Mediterranean diet scores than all other groups. CONCLUSIONS: Dietary scores and dietary clusters are complementary measures to classify dietary quality. The associations with nutritional and lifestyle factors indicate the adequate categorisation into dietary quality groups. SPONSORSHIP: European Union, US Department of Agriculture, Agriculture Research Service, under agreement (58-1950-9-001), Haak Bastiaanse-Kuneman Foundation.

Impaired protein maturation of the conjugate export pump multidrug resistance protein 2 as a consequence of a deletion mutation in Dubin-Johnson syndrome.

The Dubin-Johnson syndrome is an inherited disorder characterized by conjugated hyperbilirubinemia. The deficient hepatobiliary transport of anionic conjugates is caused by the absence of a functional multidrug-resistance protein 2 (MRP2, symbol ABCC2) from the apical (canalicular) membrane of hepatocytes. Mechanisms underlying this deficiency may include rapid degradation of mutated MRP2 messenger RNA (mRNA) or impaired MRP2 protein maturation and trafficking. We investigated the consequences of the mutation MRP2Delta(R,M), which leads to the loss of 2 amino acids from the second ATP-binding domain of MRP2. The MRP2Delta(R,M) mutation is associated with the absence of the MRP2 glycoprotein from the apical membrane of hepatocytes. Transfection of mutated MRP2 complementary DNA (cDNA) led to an MRP2Delta(R,M) protein that was only core glycosylated, sensitive to endoglycosidase H digestion, and located in the endoplasmic reticulum (ER) of transfected HEK293 and HepG2 cells. This indicated that deletion of Arg1392 and Met1393 leads to impaired maturation and trafficking of the protein from the ER to the Golgi complex. Inhibition of proteasome function resulted in a paranuclear accumulation of the MRP2Delta(R,M) protein, suggesting that proteasomes are involved in the degradation of the mutant protein. This is the first mutation in Dubin-Johnson syndrome shown to cause deficient MRP2 maturation and impaired sorting of this glycoprotein to the apical membrane.