A comparison between the abdominal and femoral adipose tissue proteome of overweight and obese women.

Body fat distribution is an important determinant of cardiometabolic health. Lower-body adipose tissue (AT) has protective characteristics as compared to upper-body fat, but the underlying depot-differences remain to be elucidated. Here, we compared the proteome and morphology of abdominal and femoral AT. Paired biopsies from abdominal and femoral subcutaneous AT were taken from eight overweight/obese (BMI ≥ 28 kg/m2) women with impaired glucose metabolism after an overnight fast. Proteins were isolated and quantified using liquid chromatography-mass spectrometry, and protein expression in abdominal and femoral subcutaneous AT was compared. Moreover, correlations between fat cell size and the proteome of both AT depots were determined. In total, 651 proteins were identified, of which 22 proteins tended to be differentially expressed between abdominal and femoral AT after removal of blood protein signals (p < 0.05). Proteins involved in cell structure organization and energy metabolism were differently expressed between AT depots. Fat cell size, which was higher in femoral AT, was significantly correlated with ADH1B, POSTN and LCP1. These findings suggest that there are only slight differences in protein expression between abdominal and femoral subcutaneous AT. It remains to be determined whether these differences, as well as differences in protein activity, contribute to functional and/or morphological differences between these fat depots.

Gonadal function and pubertal development in patients with Silver-Russell syndrome.

STUDY QUESTION: Is gonadal function affected in males and females with Silver-Russell Syndrome (SRS)? SUMMARY ANSWER: Sertoli cell dysfunction is more common in males with SRS, with 11p15 LOM, but gonadal function seems to be unaffected in females with SRS. WHAT IS KNOWN ALREADY: Males with SRS have an increased risk for genital abnormalities such as cryptorchidism and hypospadias, which could be associated with reproductive problems in later life. In SRS females, an association has been described with Mayer-Rokitansky-Küster-Hauser syndrome, which might compromise their reproductive function. STUDY DESIGN, SIZE, DURATION: Longitudinal follow-up study, involving 154 subjects, over a time period of 20 years. PARTICIPANTS/MATERIALS, SETTING, METHODS: Thirty-one SRS patients (14 males) and 123 non-SRS patients born at same gestational age (SGA; 65 males). All received growth hormone and 27.3% received additional gonadotropin-releasing hormone analog treatment (GnRHa). MAIN RESULTS AND THE ROLE OF CHANCE: Mean age at onset of puberty was 11.5 years in SRS males versus 11.6 years in non-SRS males (P = 0.51), and 10.5 years in SRS females versus 10.7 years in non-SRS females (P = 0.50). Four of the 14 SRS males had a post-pubertal inhibin-B level below the fifth percentile compared to healthy controls, and two of them an FSH above the 95th percentile, indicating Sertoli cell dysfunction. One of them had a history of bilateral cryptorchidism and orchiopexy. All SRS females had AMH, LH and FSH levels within the reference range. Pubertal duration to Tanner stage five was similar in SRS and non-SRS. Pubertal height gain was better in SRS patients who additionally received GnRHa (P < 0.01). Mean age at menarche was 13.1 years in SRS versus 13.3 years in non-SRS (P = 0.62). One SRS female had primary amenorrhea due to Müllerian agenesis. LIMITATIONS, REASONS FOR CAUTION: As this is a rare syndrome, the SRS group had a small size. WIDER IMPLICATIONS OF THE FINDINGS: As gonadal function is not affected in females with SRS, it is likely that reproductive function is also not affected. Sertoli cell dysfunction in males with SRS could cause impaired reproductive function and should be assessed during pubertal development. STUDY FUNDING/COMPETING INTEREST(S): No external funding was used for the study. The authors have no conflicts of interest.

[The effects of pharmacological and psychotherapeutic treatment of comorbid anxiety disorders in patients with bipolar disorder]. / De effectiviteit van medicamenteuze en psychotherapeutische behandeling van comorbide angststoornissen bij patiënten met bipolaire stoornis.

BACKGROUND: The co-occurrence of bipolar disorder and anxiety disorder is associated with a worse prognosis. Clinical guidelines do not give clear therapeutic recommendations on this subject.
AIM: To review the evidence on the effectiveness of both psychotherapy and pharmacotherapy for anxiety disorders in patients with a bipolar disorder.
METHOD: A systematic search in PubMed, Embase, Cochrane en Psycinfo and subsequent screening of potential studies resulted in 11 included studies.
RESULTS: Five studies examined the effect of pharmacotherapy on treatment of comorbid anxiety disorders. One of these studies showed that both olanzapine and lamotrigine provided positive results in treating the anxiety disorders, with olanzapine being the more effective of the two. Conflicting results were found for quetiapine and valproic acid. The conclusion of one study was that risperidone was not effective. No studies were found researching the effect of psychotherapy on treatment of comorbid anxiety disorders. However, two case studies and four studies that included patients with mixed diagnoses, including bipolar disorder, proposed evidence that behavioral and cognitive behavioral therapy (cbt) had a positive effect on treatment of the comorbid anxiety disorder.
CONCLUSION: There is little evidence on the treatment of comorbid anxiety disorders in people with bipolar disorder. Psychotherapy is preferred due to the uncertainty of the effects of pharmacotherapy and the associated risk of causing side effects. Pharmacotherapy can be considered in cases where this is insufficiently effective.

Long-Term Results of GH Treatment in Silver-Russell Syndrome (SRS): Do They Benefit the Same as Non-SRS Short-SGA?

CONTEXT: Silver-Russell syndrome (SRS) is a genetically heterogeneous syndrome characterized by low birth weight, severe short stature, and variable dysmorphic features. GH treatment is a registered growth-promoting therapy for short children born small for gestational age, including SRS, but there are limited data on the GH response in SRS children and on differences in response among the (epi)genetic SRS subtypes (11p15 aberrations, maternal uniparental disomy of chromosome 7 [mUPD7], and idiopathic SRS). OBJECTIVES: To compare growth and adult height between GH-treated small for gestational age children with and without SRS (non-SRS), and to analyze the difference in GH response among SRS genotypes. DESIGN AND SETTING: A longitudinal study. PARTICIPANTS: Sixty-two SRS and 227 non-SRS subjects. INTERVENTION: All subjects received GH treatment (1 mg/m(2)/d). MAIN OUTCOME MEASURES: Adult height and total height gain. RESULTS: The SRS group consisted of 31 children with 11p15 aberrations, 11 children with mUPD7, and 20 children with idiopathic SRS. At the start of GH treatment, mean (SD) height standard deviation score [SDS] was significantly lower in SRS (-3.67 [1.0]) than in non-SRS (-2.92 [0.6]; P < .001). Adult height SDS was lower in SRS (-2.17 [0.8]) than in non-SRS (-1.65 [0.8]; P = .002), but the total height gain SDS was similar. There was a trend toward a greater height gain in mUPD7 than in 11p15 (P = .12). CONCLUSION: Children with SRS have a similar height gain during GH treatment as non-SRS subjects. All (epi)genetic SRS subtypes benefit from GH treatment, with a trend toward mUPD7 and idiopathic SRS having the greatest height gain.

IGF-1 Levels, Complex Formation, and IGF Bioactivity in Growth Hormone-Treated Children With Prader-Willi Syndrome.

CONTEXT: Children with Prader-Willi syndrome (PWS) attain high-serum immunoreactive IGF-1 levels during a standard-dose GH treatment, which leads to concern, but lowering the dose deteriorates their body composition. OBJECTIVE: The objective of the study was to evaluate serum IGF-1, IGF binding protein (IGFBP)-3, and acid-labile subunit (ALS) levels, complex formation, and IGF bioactivity in GH-treated PWS children. DESIGN: This was a cross-sectional study. SETTING: The setting of the study was a Dutch PWS cohort. PARTICIPANTS: Forty GH-treated PWS children compared with 41 age- and sex-matched healthy controls participated in the study. INTERVENTIONS: Interventions included GH treatment (1.0 mg/m(2) · d = ∼0.035 mg/kg · d). MAIN OUTCOME MEASURES: Serum IGF-1, IGFBP-3, and ALS levels, complex formation, and IGF bioactivity by IGF-1 receptor kinase activation assay were measured. RESULTS: Serum IGF-1, IGFBP-3, and ALS levels and IGF-1 to IGFBP-3 ratio were significantly higher in GH-treated PWS children than in healthy controls. The 150-kDa ternary complex formation was, however, also significantly higher than in controls, indicating that most of serum IGF-1 is sequestered in the ternary 150-kDa complex with ALS and IGFBP-3. Young GH-treated PWS children [median (interquartile range) aged 5.2 (4.3-7.2) y] exhibited higher serum IGF bioactivity than controls, but no difference was observed in IGF bioactivity between older GH-treated PWS children, aged 14.9 (13.8-16.2) years, and controls. The proportion of IGF bioactivity of total serum IGF-1 was, however, lower in GH-treated PWS children than in controls. Serum immunoreactive IGF-1 levels did not correlate with IGF bioactivity in GH-treated children with PWS, in contrast to a strong positive correlation in healthy controls. CONCLUSIONS: In GH-treated PWS children, most serum IGF-1 is sequestered in the 150-kDa complex. Higher IGF bioactivity was found only in young GH-treated PWS children and not in the older ones. IGF bioactivity during GH showed a wide variation, and there was a disrupted correlation with immunoreactive IGF-1 levels, which makes immunoreactive IGF-1 levels an inappropriate indicator for GH dosing in PWS children.

New insights into factors influencing adult height in short SGA children: Results of a large multicentre growth hormone trial.

BACKGROUND: Growth hormone (GH) treatment is effective in improving adult height (AH) in short children born SGA. However, there is a wide variation in height gain, even after adjustment for predictive variables. It is therefore important to investigate new factors which can influence the response to GH. OBJECTIVE: To investigate the efficacy of GH treatment (1 mg/m(2/) day) in short SGA children on AH. To assess the relation between spontaneous catch-up growth after birth and growth during puberty on the total height gain SDS to AH. PATIENTS: Longitudinal GH trial in 170 children. RESULTS: Median age at start of GH was 7·1 years and height -3·0 SDS. AH was -1·8 SDS (TH-corrected AH -1·1 SDS) in boys and -1·9 SDS (TH-corrected AH -1·3 SDS) in girls. Spontaneous catch-up growth after birth was ≥0·5 SDS in 42% of children. In contrast to expectation, spontaneous catch-up growth was negatively correlated with total height gain SDS during GH (P = 0·009). During puberty, height SDS declined (-0·4 SDS in boys and -0·5 SDS in girls) resulting in a lower total height gain SDS than expected. Pubertal height gain was 25·5 cm in boys and 15·3 cm in girls, significantly lower compared to AGA children (P < 0·001). At onset of puberty, BA for boys and girls was moderately advanced (P = 0·02 and P < 0·001, respectively). Growth velocity was comparable to AGA children during the first two years of puberty, but thereafter significantly lower until reaching AH (P < 0·001). CONCLUSION: In contrast to our hypothesis, children with greater spontaneous catch-up growth after birth show a lower total height gain SDS during GH. Height SDS declines from mid-puberty, due to a marked early deceleration of growth velocity.

Ternary complex formation and IGFBP-3 proteolytic activity during childhood: age-dependent changes.

BACKGROUND: IGF-I is mainly sequestered in a 150-kDa ternary complex with IGF binding protein (IGFBP)-3 and the acid-labile subunit. Data on complex formation and factors influencing formation have not been established. Dissociation of IGF-I from the ternary complex is in part regulated by proteolysis of IGFBP-3, which reduces its affinity for IGF-I. Short small for gestational age (SGA) children have lower IGF-I and IGFBP-3 levels compared with healthy peers. OBJECTIVE: The objective of the study was to determine complex formation in healthy normal-statured children and assess variables influencing complex formation. Second, we determined complex formation in short SGA children. DESIGN/METHODS: Complex formation was assessed using (125)I-hIGF-I column chromatography in 70 controls (40 boys), median age 10.6 years, and 40 short SGA children (25 boys), median age 8.6 years. IGFBP-3 was determined by Western immunoblotting. RESULTS: (125)I-hIGF-I complex formation showed an age-specific pattern in healthy controls. Variables positively influencing ternary complex formation were higher serum IGF-I levels compared with IGFBP-3 levels (P < .001) and lower serum IGF-II (P < .001) and IGFBP-1 levels (P < .001). In addition, a higher presence of proteolyzed IGFBP-3 negatively influenced 150-kDa complex formation (P = .006). At a young age, healthy children showed considerable IGFBP-3 proteolytic activity, which declined with aging (P < .001). IGFBP-3 proteolytic activity was negatively correlated with IGF-I levels (P < .001). Compared with healthy controls, short SGA children showed reduced IGF-I levels (-1.3 vs 0.1 SD score) and increased proteolyzed IGFBP-3 (35.1% vs 12.2%). CONCLUSION: Age-specific normative values for (125)I-hIGF-I 150-kDa ternary complex formation are presented. A decrease in IGF-I and an increase in IGF-II, IGFBP-1, and IGFBP-3 proteolytic activity associate with reduced (125)I-hIGF-I ternary complex formation. Our results suggest that in conditions in which IGF-I levels are low, such as young age and in short SGA children, IGFBP-3 proteolytic activity is increased to ensure IGF-I bioavailability.

Acid-labile subunit levels and the association with response to growth hormone treatment in short children born small for gestational age.

AIMS: To determine acid-labile subunit (ALS) levels in short small for gestational age (SGA) children and to assess the relationship between ALS levels and several clinical and laboratory characteristics. Also, to assess whether adding ALS levels to a growth prediction model might improve the long-term growth prediction. DESIGN/METHODS: ALS levels were measured in 312 short SGA children at the start of growth hormone (GH) treatment. RESULTS: Median (interquartile range) ALS of all subjects was -0.5 SDS, significantly below the 0 SDS (p < 0.001). In 34 children (11%), ALS levels were ≤-2 SDS. ALS SDS correlated significantly with height SDS (r = 0.24, p < 0.001), weight SDS (r = 0.30, p < 0.001), BMI SDS (r = 0.20, p = 0.001), IGF-I SDS (r = 0.56, p < 0.001) and IGFBP-3 SDS (r = 0.67, p < 0.001). ALS SDS was also positively correlated with fasting insulin (r = 0.41, p < 0.001) and glucose levels (r = 0.33, p < 0.001), and HOMA-IR (r = 0.35, p < 0.001). Baseline ALS levels contributed to the long-term growth prediction of GH treatment (5%, p < 0.001). CONCLUSION: Short SGA children tend to have lower ALS levels compared to controls, albeit less reduced than IGF-I and IGFBP-3 levels. Our data suggest that ALS may be involved in glucose homeostasis. Determination of ALS levels before the start of GH treatment in short SGA children contributes moderately to a more accurate prediction of the growth response to GH treatment.

[Forcing patients with bipolar disorder to make a financial contribution to secondary psychiatric care may make them forsake care completely]. / Vraaguitval bij poliklinische patiënten met een bipolaire stoornis als gevolg van de eigen bijdrage in de tweedelijns-ggz.

BACKGROUND: In 2012 patients were required to make a personal financial contribution for secondary mental health care over and above their standard insurance fee. According to current guidelines, the majority of patients with bipolar disorder must be treated as outpatients at psychiatric clinics. It was to be expected that some patients would decide to discontinue their outpatient treatment on account of the newly imposed personal financial contribution. AIM: To obtain insight into the size and characteristics of the group of patients with bipolar disorder who were thinking about giving up treatment or had already decided to give it up because of the imposition of the personal financial contribution; also to find out which factors influenced patients' decisions and to discover how patients perceived the role of the GP as the provider of subsequent psychiatric care. METHOD: We conducted an exploratory study by sending a survey to all outpatients receiving treatment at three clinics specialising in the treatment of bipolar disorder. RESULTS: 640 patients responded to the survey (55% response); 15% of these patients were thinking about giving up treatment or had already decided to stop their treatment. They were influenced primarily by financial considerations. Two-thirds of the respondents did not consider that the GP was as a suitable alternative to outpatient care at a clinic. Even patients with moderate to serious symptoms were considering leaving secondary care. CONCLUSION: The obligatory financial contribution for secondary mental health care could have considerable consequences for a small number of patients with severe mood disorder who are currently treated as outpatients in secondary facilities. The increase in the compulsory & squo;own risk' insurance fee as from 2013 could have similar consequences.

Anti-Mullerian hormone in short girls born small for gestational age and the effect of growth hormone treatment.

Background Fetal growth restriction is thought to negatively influence reproductive function in later life. Serum anti-Müllerian hormone (AMH) is a marker of the primordial follicle pool. The objectives of this study were to evaluate the effect of being born small for gestational age (SGA) on serum AMH levels and to investigate the effect of growth hormone (GH) treatment on serum AMH levels in short SGA girls. METHODS Serum AMH levels were investigated in 246 prepubertal girls aged 3-10 years: 119 untreated short SGA and 127 healthy controls. Associations between AMH levels and clinical characteristics were analysed using multiple regression analyses. In addition, we investigated the effect of GH treatment on serum AMH levels in short SGA girls. RESULTS Serum AMH levels were similar in short SGA and healthy control girls (P= 0.95). In short SGA girls, AMH levels were not significantly influenced by birth weight standard deviation score (SDS), birth length SDS and gestational age, even after adjustment for age, height SDS and body mass index (BMI) SDS at sampling, socio-economic status and maternal smoking during gestation. Serum AMH levels did not change during 4 years of GH treatment in short SGA girls (P= 0.43). ConclusionS Serum AMH levels in prepubertal short SGA girls are similar to healthy controls, indicating that the follicle pool is not compromised due to SGA birth. GH treatment has no effect on AMH levels in short SGA girls.

Absence of an adipogenic effect of rosiglitazone on mature 3T3-L1 adipocytes: increase of lipid catabolism and reduction of adipokine expression.

AIMS/HYPOTHESIS: The thiazolidinedione (TZD) rosiglitazone is a peroxisome proliferator-activated receptor-gamma agonist that induces adipocyte differentiation and, hence, lipid accumulation. This is in apparent contrast to the long-term glucose-lowering, insulin-sensitising effect of rosiglitazone. We tested whether the action of rosiglitazone involves specific effects on mature adipocytes, which are different from those on preadipocytes. MATERIALS AND METHODS: Differentiated mature 3T3-L1 adipocytes were used as an in vitro model. Transcriptomics, proteomics and assays of metabolism were applied to assess the effect of rosiglitazone in different insulin and glucose conditions. RESULTS: Rosiglitazone does not induce an increase, but rather a decrease in the lipid content of mature adipocytes. Analysis of transcriptome data, confirmed by quantitative RT-PCR and measurements of lipolysis, indicates that an altered energy metabolism may underlie this change. The pathway analysis shows a consistent picture dominated by lipid catabolism. In addition, we confirmed at both mRNA level and protein level that rosiglitazone represses adipokine expression and production, except for genes encoding adiponectin and apolipoprotein E. Moreover, transcriptome changes indicate that a general repression of genes encoding secreted proteins occurs. CONCLUSIONS/INTERPRETATION: Our findings suggest that the change of adiposity as seen in vivo reflects a shift in balance between the different effects of TZDs on preadipocytes and on mature adipocytes, while the changes in circulating adipokine levels primarily result from an effect on mature adipocytes.

Insulin modulates the secretion of proteins from mature 3T3-L1 adipocytes: a role for transcriptional regulation of processing.

AIMS/HYPOTHESIS: Under conditions of insulin resistance and type 2 diabetes, fat cells are subjected to increased levels of insulin, which may have a major impact on the secretion of adipokines. MATERIALS AND METHODS: Using transcriptomics and proteomics, we investigated how insulin affects the transcription and protein secretion profile of mature 3T3-L1 adipocytes. RESULTS: We found that insulin has a significant impact on protein secretion of 3T3-L1 adipocytes. However, transcription is not the major regulation point for these secreted proteins. For extracellular matrix components, our data suggest that the mRNA level of processing enzymes, but not of target proteins, is the regulating point at which insulin stimulates secretion and function of the relevant proteins. Among these enzymes, we report a novel finding, namely that sulfatase 2 gene is regulated by insulin, which may induce a functional change in cultured adipocytes. CONCLUSIONS/INTERPRETATION: We propose that enhancement of protein processing and secretion rather than transcription of the secreted protein genes is part of the strategic role of insulin in the induction of cellular responses.

Unconditional security of a three state quantum key distribution protocol.

Quantum key distribution (QKD) protocols are cryptographic techniques with security based only on the laws of quantum mechanics. Two prominent QKD schemes are the Bennett-Brassard 1984 and Bennett 1992 protocols that use four and two quantum states, respectively. In 2000, Phoenix et al. proposed a new family of three-state protocols that offers advantages over the previous schemes. Until now, an error rate threshold for security of the symmetric trine spherical code QKD protocol has been shown only for the trivial intercept-resend eavesdropping strategy. In this Letter, we prove the unconditional security of the trine spherical code QKD protocol, demonstrating its security up to a bit error rate of 9.81%. We also discuss how this proof applies to a version of the trine spherical code QKD protocol where the error rate is evaluated from the number of inconclusive events.

Protein profiling of 3T3-L1 adipocyte differentiation and (tumor necrosis factor alpha-mediated) starvation.

The increased incidence of obesity and related disorders in Western societies requires a thorough understanding of the adipogenic process. Data at the protein level of this process are scarce. Therefore we performed a proteome analysis of differentiating and starving 3T3-L1 cells using two-dimensional gel electrophoresis combined with mass spectrometry. Effects of different starvation conditions were examined by subjecting 3T3-L1 adipocytes to caloric restriction, either in the absence or the presence of the lipolysis inducer tumor necrosis factor-alpha. Ninety-three differentially expressed proteins were found during differentiation and starvation of 3T3-L1 cells, 50 of which were identified. GenMAPP/MAPP-finder software revealed a non-reciprocal regulation of the glycolytic pathway during 3T3-L1 differentiation followed by starvation. Furthermore, proteins involved in growth regulation, cytoskeletal rearrangements and protein modification, 16 of which have not been described before in 3T3-L1 cells, were identified. In conclusion, our data provide valuable information for further understanding of the adipogenic process.

Profiling of the secreted proteins during 3T3-L1 adipocyte differentiation leads to the identification of novel adipokines.

Adipose tissue is an endocrine organ capable of secreting a number of adipokines with a role in the regulation of adipose tissue and whole-body metabolism. We used two-dimensional gel electrophoresis combined with mass spectrometry to profile the secreted proteins from (pre)adipocytes. The culture medium of 3T3-L1 cells during adipocyte differentiation was screened, and 41 proteins that responded to blocking of secretion by 20 degrees C treatment and/or brefeldin A treatment were identified. Prohibitin, stress-70 protein, and adhesion-regulating molecule 1 are reported for the first time as secreted proteins. In addition, procollagen C-proteinase enhancer protein, galectin-1, cyclophilin A and C, and SF20/IL-25 are newly identified as adipocyte secreted factors. Secretion profiles indicated a dynamic environment including an actively remodeling extracellular matrix and several factors involved in growth regulation.

[Apathy syndrome: a clinical entity?]. / Apathiesyndroom: een klinische entiteit?

Apathy is defined as a disorder of motivation that expresses itself at an emotional, cognitive and behavioural level. Apathy can occur as a symptom and a syndrome. In the recent years diagnostic criteria and a number of scales for measuring apathy in elderly with psychiatric or neurological disorders have been introduced. Two scales are specifically developed to measure apathy, the Apathy Evaluation Scale (AES) from Marin and the Apathy Scale (AS) from Starkstein. Both scales have been translated into Dutch. The AS is more convenient. The AS in addition can be used when applying the criteria for the apathy syndrome which has been introduced in 2001 by Starkstein. In addition, the Neuropsychiatric Inventory (NPI) and the 'Gedragsobservatieschaal voor de Intramurale Psychogeniatrie' (GIP) (a scale in Dutch) have an apathy domain. Conceptual problems surrounding apathy have only partly been resolved. The criteria for the apathy syndrome can only be used for assessing the extent of the problem. Apathy and depression are strongly correlated. Studies show that apathy as a syndrome can occur without concomitant depression in the elderly, but regularly occurs besides a depressive disorder, in percentages varying between 9% and 53% of the population under study. Especially the varying validity of an apathy syndrome in relation to late life depression needs further clarification.

[Manic state during the addition of lithium in the case of depression resistant to imipramine]. / Ontremming tijdens toevoeging van lithium bij depressie resistent tegen imipramine.

Two women, aged 65 and 43 years, who were suffering from tricyclic-resistant depressions, developed a (hypo)manic state after a few days of lithium addition. In both cases the lithium plasma level was fairly low. For the first woman an increase in the lithium dosage combined with a substitution of the antidepressant resulted in a complete recovery and for the second woman, an increase in the lithium dosage combined with the continued use of the same antidepressant resulted in a recovery to a large extent. In animal experiments lithium addition resulted in a rapid increase in serotonergic neurotransmission, due to an increase in serotonin synthesis and release. This may explain a rapid amelioration of depression as well as the development of (hypo)manic symptoms. Depending on the severity and the persistence of hypomanic symptoms, the antidepressant can be either continued or withdrawn but the lithium dose must be adjusted in order to reach an adequate plasma level of lithium.

Multidrug resistance protein MRP1 protects against the toxicity of the major lipid peroxidation product 4-hydroxynonenal.

4-Hydroxynonenal (4HNE) is the most prevalent toxic lipid peroxidation product formed during oxidative stress. It exerts its cytotoxicity mainly by the modification of intracellular proteins. The detection of 4HNE-modified proteins in several degenerative disorders suggests a role for 4HNE in the onset of these diseases. Efficient protection mechanisms are required to prevent the intracellular accumulation of 4HNE. The toxicity of 4HNE was tested with the small cell lung cancer cell lines GLC(4) and the multidrug-resistance-protein (MRP1)-overexpressing counterpart GLC(4)/Adr. In the presence of the MRP1 inhibitor MK571 or the GSH-depleting agent buthionine sulphoximine, both cell lines became more sensitive and showed decreased survival. Transport experiments were performed with the (3)H-labelled glutathione S-conjugate of 4HNE ([(3)H]GS-4HNE) with membrane vesicles from GLC(4)-derived cell lines with different expression levels of MRP1. [(3)H]GS-4HNE was taken up in an ATP-dependent manner and the transport rate was dependent on the amount of MRP1. The MRP1 inhibitor MK571 decreased [(3)H]GS-4HNE uptake. MRP1-specific [(3)H]GS-4HNE transport was demonstrated with membrane vesicles from High Five insect cells overexpressing recombinant MRP1. Kinetic experiments showed an apparent K(m) of 1.6+/-0.21 microM (mean+/-S.D.) for MRP1-mediated [(3)H]GS-4HNE transport. In conclusion, MRP1 has a role in the protection against 4HNE toxicity and GS-4HNE is a novel MRP1 substrate. MRP1, together with GSH, is hypothesized to have a role in the defence against oxidative stress.

ATP- and glutathione-dependent transport of chemotherapeutic drugs by the multidrug resistance protein MRP1.

The present study was performed to investigate the ability of the multidrug resistance protein (MRPI) to transport different cationic substrates in comparison with MDR1-P-glycoprotein (MDR1). Transport studies were performed with isolated membrane vesicles from in vitro selected multidrug resistant cell lines overexpressing MDR1 (A2780AD) or MRP1 (GLC4/Adr) and a MRP1-transfected cell line (S1(MRP)). As substrates we used 3H-labelled derivatives of the hydrophilic monoquaternary cation N-(4',4'-azo-in-pentyl)-21-deoxy-ajmalinium (APDA), the basic drug vincristine and the more hydrophobic basic drug daunorubicin. All three are known MDR1-substrates. MRP1 did not mediate transport of these substrates per se. In the presence of reduced glutathione (GSH), there was an ATP-dependent uptake of vincristine and daunorubicin, but not of APDA, into GLC4/Adr and S1(MRP) membrane vesicles which could be inhibited by the MRP1-inhibitor MK571. ATP- and GSH-dependent transport of daunorubicin and vincristine into GLC4/Adr membrane vesicles was inhibited by the MRP1-specific monoclonal antibody QCRL-3. MRP1-mediated daunorubicin transport rates were dependent on the concentration of GSH and were maximal at concentrations > or = 10 mM. The apparent KM value for GSH was 2.7 mM. Transport of daunorubicin in the presence of 10 mM GSH was inhibited by MK571 with an IC50 of 0.4 microM. In conclusion, these results demonstrate that MRP1 transports vincristine and daunorubicin in an ATP- and GSH-dependent manner. APDA is not a substrate for MRP1.

Transport of glutathione conjugates into secretory vesicles is mediated by the multidrug-resistance protein 1.

Intracellular glutathione-conjugate transport was evaluated in the human small cell lung carcinoma cell line GLC4 with low multidrug resistance protein (MRP1) expression and its 300x doxorubicin-resistant, MRP1-over-expressing, GLC4-Adr subline. Transport of non-toxic concentrations of monochlorobimane and 5-chloro-methyl fluorescein diacetate was evaluated using fluorescence microscopy. After exposure to these compounds, fluorescence was observed especially in intracellular vesicles in GLC4-Adr. Immunotransmission electron microscopy showed that MRP1 was present in the vesicle membranes and plasma membrane, while inside the vesicles the glutathione conjugate of 1-chloro-2,4-dinitrobenzene could be detected. Experiments with brefeldin A, which induces arrest in vesicle release from the Golgi complex, indicated that these vesicles may originate from the trans-Golgi network. In GLC4-Adr cells, doxorubicin also was transported in vesicles, with an arrest in vesicle release from the Golgi complex. Our results indicate that MRP1 functions as a glutathione-conjugate transporter not only at the plasma membrane but also in intracellular secretory vesicles.