Background and purpose: Organic anion transporting polypeptide 1B3 (OATP1B3)(SLCO1B3) mediates the uptake of endogenous substrates (e.g. estrone-3-sulphate) and drugs (e.g. pravastatin) from blood into hepatocytes. Structure-based modelling of OATP1B3 suggested that a pore with a positive electrostatic potential contributes to the transport mechanism. Therefore, we investigated the role of conserved positively charged amino acids for OATP1B3-mediated uptake of sulphobromophthalein (BSP) and pravastatin. Experimental approach: Residues Lys28, Lys41 and Arg580 in OATP1B3 were substituted by alanine, arginine, glutamine, glycine or lysine. Using immunofluorescence, immunoblot analysis and cellular uptake assays, the effect of these mutations on protein expression and transport activity was investigated. Key results: Immunofluorescence revealed that all mutants were localized in the plasma membrane with partial intracellular retention of the Arg580>Ala and Arg580>Lys mutants. Lys41>Ala, Lys41>Gln, Lys41>Gly, Arg580>Gly and Arg580>Lys showed significantly reduced transport for BSP and pravastatin. Kinetic analyses of BSP transport revealed a significant reduction of V(max) normalized to cell surface protein expression for Lys41>Ala (wild type: 190 +/- 8, Lys41>Ala:16 +/- 4 pmol (mg protein)(-1) min(-1), P < 0.001), whereas V(max) of Lys41>Arg and Arg580>Lys (103 +/- 8 and 123 +/- 14 pmol (mg protein)(-1) min(-1), P > 0.05) did not change significantly. This suggests that the positive charges at positions 41 and 580 are important for transport activity of BSP. Structural modelling indicated that the positively charged side chain of Lys41 is flexible within the pore. The orientation of Arg580 is defined by adjacent residues Glu74 and Asn77, which was confirmed by kinetic analysis of Glu74>Ala. Conclusions and implications: We demonstrated that the conserved positively charged amino acids Lys41 and Arg580 are pivotal to the transport activity of OATP1B3.

Uptake transporters in the basolateral membrane of hepatocytes are important for the hepatobiliary elimination of drugs. Further, since drug-metabolizing enzymes are located intracellularly, uptake into hepatocytes is a prerequisite for their subsequent metabolism. Therefore, alteration of uptake transporter function (e.g., by concomitantly administered drugs or due to functional consequences of genetic variations, leading to reduced transport function) may result in a change in drug pharmacokinetics. In this review, we focus on the hepatocellularly expressed members of the OATP and OCT family, their impact on transport-mediated drug-drug interactions, and on the functional consequences of variations in genes encoding these transporters.

BACKGROUND: Suicidal ideation is common in patients suffering from depression, but it often remains undetected. General practitioners play an important role in the management of depression and suicidality. The aim of this study was to identify predictors for suicidal ideation in patients with major depression in primary health care. METHOD: We conducted a cross-sectional study. Patients were recruited from 74 primary care practices in Germany. Data was collected between April 2005 and July 2006. We calculated a binary logistic regression model to evaluate whether depression severity (Patient Health Questionnaire, PHQ-9), physical pain (SF-36 Physical Pain Scale), physical comorbidity, intake of antidepressant medication, sex and age were predictors of suicidal ideation. RESULTS: We enrolled 626 patients, aged 18 to 80 with major depression. Depression severity (OR 1.16 per unit PHQ-9 score, 95% CI 1.09-1.22, p<0.001) and male sex (OR 1.71, 95% CI 1.13-2.58, p=0.012) were associated with suicidal ideation, while absence of pain (OR 0.99 per unit SF-36 Physical Pain Scale, 95% CI 0.98-1.00, p=0.004) and older age (>60) compared to the reference group aged 40 to 60 (OR 0.55, 95% CI 0.35-0.86, p=0.009) were protective factors. LIMITATIONS: This cross-sectional study allows the generation of hypotheses. CONCLUSIONS: Depression severity is a predictor for suicidal ideation in primary care patients with major depression. In addition, physical pain appears to be a predictor. Results should be confirmed using a prospective study design.

PURPOSE. Latanoprost, a prostaglandin F(2alpha) analogue, has become one of the most widely used medications for treatment of glaucoma. We hypothesized that organic anion transporting polypeptides (OATPs) are responsible for the uptake of latanoprost into ocular tissues and hence that they contribute to the interindividual differences in drug concentrations and effects. METHODS. Expression of prostaglandin (PG) transporters (OATP2A1, OATP2B1) in human ocular tissues were determined using real-time RT-PCR and immunofluorescence. The inhibitory interactions between latanoprost and its active metabolite (the free acid), and uptake of prototypical substrates (PGE(2) and bromosulfophthalein, BSP) were tested in stably transfected Human Embryonic Kidney cells overexpressing either OATP2A1 or OATP2B1. These cells were also used to investigate whether latanoprost and latanoprost acid are substrates of OATP2A1 or OATP2B1. RESULTS. OATP2A1 and OATP2B1 mRNA expression was highest in the choroid/retinal pigment epithelium (RPE) complex and ciliary body. OATP2A1 protein expression was most prominent in the RPE as well as in epithelial and endothelial cell layers of anterior segment tissues, such as cornea, conjunctiva, iris, and ciliary body, whereas OATP2B1 protein was additionally expressed in trabecular meshwork, Schlemm canal, and choroidal vasculature. Latanoprost and latanoprost acid significantly inhibited both OATP2A1 and OATP2B1. Uptake experiments demonstrated that latanoprost acid is effectively transported by OATP2A1 [affinity constant (K(m))= 5.4 muM, maximum uptake rate (V(max))= 21.5 pmol/mg protein/min] and less effectively by OATP2B1. CONCLUSIONS. The results presented herein suggest that at least OATP2A1 plays a role in the intraocular disposition of the therapeutically used prostanoid latanoprost.

Signaling output of bone morphogenetic proteins (BMPs) is determined by two sets of opposing interactions, one with heterotetrameric complexes of cell surface receptors, the other with secreted antagonists that act as ligand traps. We identified two mutations (N445K,T) in patients with multiple synostosis syndrome (SYM1) in the BMP-related ligand GDF5. Functional studies of both mutants in chicken micromass culture demonstrated a gain of function caused by a resistance to the BMP-inhibitor NOGGIN and an altered signaling effect. Residue N445, situated within overlapping receptor and antagonist interfaces, is highly conserved among the BMP family with the exception of BMP9 and BMP10, in which it is substituted with lysine. Like the mutant GDF5, both BMPs are insensitive to NOGGIN and show a high chondrogenic activity. Ectopic expression of BMP9 or the GDF5 mutants resulted in massive induction of cartilage in an in vivo chick model presumably by bypassing the feedback inhibition imposed by endogenous NOGGIN. Swapping residues at the mutation site alone was not sufficient to render Bmp9 NOG-sensitive; however, successive introduction of two additional substitutions imparted high to total sensitivity on customized variants of Bmp9. In conclusion, we show a new mechanism for abnormal joint development that interferes with a naturally occurring regulatory mechanism of BMP signaling.

Signals from pharmacovigilance studies indicate that women are at higher risk for adverse drug reactions (ADRs) due to diuretics. Despite the long-term use of torasemide, there are few studies investigating gender differences of torasemide pharmacokinetics in the hospital setting. Therefore, torasemide pharmacokinetics were investigated in 90 patients (45 women, 45 men) during steady-state conditions. Torasemide elimination was significantly reduced in women compared with men (eg, body-weight-normalized area under the concentration-time curve: 42.1 +/-20.4 vs 30.9 +/-10.3 kg*h/L; P <.001). Among the investigated genetic factors [SLC22A11(OAT4), SLCO1B1(OATP1B1), CYP2C9], only the SLCO1B1c.521T>C polymorphism had a significant influence on torasemide pharmacokinetics. Using cell lines expressing OATP1B1, the authors identified torasemide as OATP1B1 substrate (Km = 6.2 microM) with a significant reduction of uptake by the 521C-variant. Taken together, gender differences in torasemide pharmacokinetics are likely to contribute to a higher rate of ADRs in women, which has, for example, been observed in a German Pharmacovigilance Project with 66% of hospitalizations due to torasemide ADRs occurring in women.

OBJECTIVE:: Aiming at avoidance of futile surgery, we have tested whether radiofrequency ablation (RFA) may be used as first-line treatment in patients with colorectal metastases (CRLM) occurring within the first year after colorectal surgery. SUMMARY BACKGROUND DATA:: Surgical resection is the standard treatment in patients with CRLM. Major retrospective analyses have identified the interval between colorectal surgery and the occurrence of CRLM to be of prognostic importance. So far, it is unknown whether survival of the respective patients is hampered if RFA is used as first-line treatment. METHODS:: According to a clinical pathway, we have treated patients with CRLM detected within the first year after colorectal surgery preferentially by RFA (n = 28). Resection (n = 82) was performed in patients who were deemed not amenable to RFA due to number, size, or location of metastatic lesions. The diameter of lesions differed between the groups. All other characteristics of patients and lesions were comparable. Local recurrence and new hepatic lesions were treated with repeated RFA or surgery whenever possible. RESULTS:: Local recurrence at the site of ablation or resection occurred in 32% and 4%(P < 0.001), new metastases apart from the site of previous treatment in 50% and 34%(P = 0.179), and systemic recurrence in 32% and 37%(P = 0.820) of the patients after RFA and surgery, respectively. Time to progression was significantly shorter in patients primarily treated with RFA (203 vs. 416 days; P = 0.017). After primary treatment, 9 RFA patients and 8 surgery patients were amenable to repeated RFA or repeated surgery resulting in identical rates of disease-free patients and identical 3-year overall survival in both treatment groups: 67% and 60%, respectively; P = 0.93. CONCLUSIONS:: Despite striking differences in local tumor recurrence and shorter time to progression, survival in patients with early CRLM does not depend on the mode of primary hepatic treatment.

BACKGROUND: Standard treatment of patients with breast cancer decreases with age and older persons are mostly excluded from clinical trials. We hypothesized that non-adherence to treatment guidelines occurs for women aged >/=70 years and changes overall survival (OAS) and disease-free survival (DFS). PATIENTS AND METHODS: We enrolled 1922 women aged >/=50 years with histologically confirmed invasive breast cancer treated at the University of Ulm from 1992 to 2005. Adherence to guidelines and effects on OAS and DFS for women aged >/=70 years was compared with that for younger women (50-69 years). RESULTS: Women >70 years less often received recommended breast-conserving therapy (70-79 years: 74%-83%;>79 years: 54%) than women aged </=69 years (93%). Non-adherence to the guidelines on radiotherapy (<70 years: 9%; 70-79 years: 14%-27%;>79 years: 60%) and chemotherapy (<70 years: 33%; 70-79 years: 54%-77%;> 79 years: 98%) increased with age. Omission of radiotherapy significantly decreased OAS [</=69 years: hazard ratio (HR)= 3.29; P <0.0001;>/=70 years: HR = 1.89; P = 0.0005] and DFS (</=69 years: HR = 3.45; P <0.0001;>/=70 years: HR = 2.14; P <0.0001). OAS and DFS did not differ significantly for adherence to surgery, chemotherapy, or endocrine therapy. CONCLUSION: Our study confirms that substandard treatment increases considerably with age. Omission of radiotherapy had the greatest impact on OAS and DFS in the elderly population.

BACKGROUND: Case management by health care assistants in small primary care practices provides unclear benefit for improving depression symptoms. OBJECTIVE: To determine whether case management provided by health care assistants in small primary care practices is more effective than usual care in improving depression symptoms and process of care for patients with major depression. DESIGN: Cluster randomized, controlled trial. A central automated system generated the randomization scheme, which was stratified by urban and rural practices; allocation sequence was concealed until groups were assigned. SETTING: 74 small primary care practices in Germany from April 2005 to September 2007. PATIENTS: 626 patients age 18 to 80 years with major depression. INTERVENTION: Structured telephone interview to monitor depression symptoms and support for adherence to medication, with feedback to the family physician. MEASUREMENTS: Depression symptoms at 12 months, as measured by the Patient Health Questionnaire-9 (PHQ-9); secondary outcomes were patient assessment of chronic illness care, adherence to medication, and quality of life. RESULTS: A total of 310 patients were randomly assigned to case management and 316 to usual care. At 12 months, 249 intervention recipients and 278 control patients were assessed; 555 patients were included in a modified intention-to-treat-analysis (267 intervention recipients vs. 288 control patients). Compared with control patients, intervention recipients had lower mean PHQ-9 values in depression symptoms (-1.41 [95% CI,-2.49 to -0.33]; P = 0.014), more favorable assessments of care (3.41 vs. 3.11; P = 0.011), and increased treatment adherence (2.70 vs. 2.53; P = 0.042). Quality-of-life scores did not differ between groups. LIMITATION: Patients, health care assistants, family physicians, and researchers were not blinded to group assignment, and 12-month follow-up of patients was incomplete. CONCLUSION: Case management provided by primary care practice-based health care assistants may reduce depression symptoms and improve process of care for patients with major depression more than usual care. PRIMARY FUNDING SOURCE: German Ministry of Education and Research.

Aim: The uptake of drugs from the blood into the renal tubular cells is a key determinant for renal secretion and may influence their systemic plasma concentrations and extrarenal effects. Metformin, used for treatment of type 2 diabetes, is taken up into renal tubular cells by the organic cation transporter 2 (OCT2). Because many patients with type 2 diabetes receiving metformin are concomitantly treated with beta-blockers, we tested whether beta-blockers can inhibit OCT2-mediated drug transport. Method: Using Madin-Darby canine kidney II cells stably expressing the uptake transporter OCT2, we analysed whether the beta-blockers bisoprolol, carvedilol, metoprolol and propranolol inhibit the transport of OCT2 substrates 1-methyl-4-phenylpyridinium (MPP(+)) and metformin. Results: Neither bisoprolol nor metoprolol significantly inhibited the uptake of MPP(+), whereas a significant inhibition was observed for carvedilol und propranolol (half maximal inhibitory concentration IC(50): 26.3 and 67.5 muM) respectively. Moreover, all beta-blockers significantly inhibited OCT2-mediated metformin uptake (IC(50) for bisoprolol: 2.4 muM, IC(50) for carvedilol: 2.3 muM, IC(50) for metoprolol: 50.2 muM and IC(50) for propranolol: 8.3 muM). Conclusion: These in vitro results demonstrate that alterations of uptake transporter function by beta-blockers have to be considered as potential mechanisms underlying drug-drug interactions in the kidney.