Bridging Systems Medicine and Patient Needs.

While there is widespread consensus on the need both to change the prevailing research and development (R&D) paradigm and provide the community with an efficient way to personalize medicine, ecosystem stakeholders grapple with divergent conceptions about which quantitative approach should be preferred. The primary purpose of this position paper is to contrast these approaches. The second objective is to introduce a framework to bridge simulation outputs and patient outcomes, thus empowering the implementation of systems medicine.

System L amino acid transporter LAT1 accumulates O-(2-fluoroethyl)-L-tyrosine (FET).

O-(2-fluoroethyl)-L-tyrosine (FET) labeled with fluorine-18 is an important and specific tracer for diagnostics of glioblastoma via positron emission tomography (PET). However, the mechanism of its quite specific accumulation in tumor tissue has not been understood so far. In this work we demonstrate that [(3)H]L-tyrosine is primarily transported by the system L transporter LAT1 in human LN229 glioblastoma cells. FET reduced tyrosine transport, suggesting that it shares the same uptake pathway. More importantly, accumulation of FET was significantly reduced after siRNA-mediated downregulation of LAT1. Xenopus laevis oocytes expressing human LAT1 together with the glycoprotein 4F2hc (necessary to pull LAT-1 to the plasma membrane) exhibited a similar accumulation of FET as observed in glioblastoma cells. In contrast, no accumulation was observed in control oocytes, not overexpressing an exogenous transporter. Because LAT1 works exclusively as an exchanger of amino acids, substrates at one side of the membrane stimulate exchange against substrates at the other side. Extracellular FET stimulated the efflux of intracellular [(3)H]L-leucine, demonstrating that FET is indeed an influx substrate for LAT1. However, FET injected into oocytes was not able to stimulate uptake of extracellular [(3)H]L-leucine, indicating that FET is not a good efflux substrate. Our data, therefore, suggest that FET is trapped within cells due to the asymmetry of its intra- and extracellular recognition by LAT1. If also found for other transporters in tumor cells, asymmetric substrate recognition may be further exploited for tumor-specific accumulation of PET-tracers and/or other tumor-related drugs.

Rationale for carbon ion therapy in high-grade glioma based on a review and a meta-analysis of neutron beam trials.

PURPOSE: The standard treatment of high-grade glioma is still unsatisfactory: the 2-year survival after radiotherapy being only 10-25%. A high linear energy transfer (LET) ionising radiotherapy has been used to overcome tumour radioresistance. An overview of the field is needed to justify future prospective controlled studies on carbon ion therapy. MATERIALS AND METHODS: A meta-analysis of clinical trials on neutron beam therapy and a literature review of clinical investigations on light ion use in high-grade glioma were carried out. RESULTS: Four randomised controlled trials on neutron beam therapy were retained. The meta-analysis showed a non-significant 6% increase of two-year mortality (Relative risk [RR]=1.06 [0.97-1.15]) in comparison with photon therapy. Two phase I/II trials on carbon and neon ion therapy reported for glioblastoma 10% and 31% two-year overall survivals and 13.9 and 19.0 months median survivals, respectively. CONCLUSION: This meta-analysis suggests that neutron beam therapy does not improve the survival of high-grade glioma patients while there is no definitive conclusion yet regarding carbon therapy. The ballistic accuracy and the improved biological efficacy of carbon ions renew the interest in prospective clinical trials on particle beam radiotherapy of glioma and let us expect favourable effects of dose escalation on patients' survival.

A numerical study of the blocking of migraine by Rolando sulcus.

Migraine with aura is a complex phenomena, which remains still not completely understood. A striking fact is that its clinical manifestations may change from one patient to another. Migraine with aura may only consist in visual hallucinations, but may as well go on to temporary aphasy. However, for all the patients it always stops before it goes from area 3 to area 4, thus just before crossing Rolando sulcus. In this paper, we give arguments showing that the detailed geometry of Rolando sulcus in human cortex may by itself explain that migraine attack never crosses Rolando sulcus.

A global phenomenological model of ischemic stroke with stress on spreading depressions.

In this paper, we establish a new global phenomenological model of ischemic stroke. It takes into account local ischemia, energy reduction, propagation of spreading depressions (SD), damages to the cells and cellular death by apoptosis or necrosis. The spatial diffusion of the ions in the extracellular space which triggers the propagation of SD is a central point here. First we expose the various biological hypotheses that we have made in this model, and then we explain how to determine the parameters and solve the system of equations that we obtain. Next we present some results of this model: we simulate a KCl injection and then a local ischemia. Finally we discuss results and propose some improvements for this model.

[Non-inferiority trial used in venous thromboembolic disease. A warily interpretation is necessary!]. / Essais de non-infériorité dans la maladie thromboembolique veineuse. Une lecture critique est nécessaire!

INTRODUCTION: Equivalence trials are actually frequently used to prove non-inferiority in anticoagulant therapy. Equivalence trials consist to demonstrate that two treatments are not too much different. This difference has to be under a margin previously determined. The margin corresponds to an efficacy loss that is defined to be acceptable, in accordance to the advantages due to the new treatment. The aim of this work is to explore the equivalence trial published in the thromboembolic disease by focus on the non-inferiority margin used. METHODS: We identified published equivalence trials in the venous thromboembolic disease, by a systematic search in Medline. We calculated the efficacy loss by reference with the value of the smallest effect size of the standard treatment compared to placebo. RESULTS: We found 9 equivalence trials used in venous thromboembolic disease. The mean value of the efficacy loss was 434%, and the median value was 357%. Eighty-five percent of the values of the efficacy loss were above 100%. DISCUSSION: Eighty-five percent of the equivalence trials conclude to equivalence despite a complete efficacy loss of the effect of the standard treatment compared to placebo. The results of equivalence trials should be interpreted warily. The corresponding non-inferiority margin should be chosen more rigorously and by reference with the value of the smallest effect size of the standard treatment compared to placebo.

A multiscale mathematical model of avascular tumor growth to investigate the therapeutic benefit of anti-invasive agents.

With the aim of inhibiting cancer growth and reducing the risk of metastasis, pharmaceutical companies in the early 1990s developed anti-metastatic agents called inhibitors of metalloproteinases (MMPi). Despite the promising results obtained in pre-clinical studies, results of Phase III trials have been somewhat disappointing for late stage cancer patients. With the aim of mathematically investigating this therapeutic failure, we developed a mechanistically based model which integrates cell cycle regulation and macroscopic tumor dynamics. By simulating the model, we evaluated the efficacy of MMPi therapy. Simulation results predict the lack of efficacy of MMPi in advanced cancer patients. The theoretical model may aid in evaluating the efficacy of anti-metastatic therapies, thus benefiting the design of prospective clinical trials.

Low protein diets for chronic kidney disease in non diabetic adults.

BACKGROUND: For more than fifty years, low protein diets have been proposed to patients with kidney failure. However, the effects of these diets in preventing severe renal failure and the need for maintenance dialysis have not been resolved. OBJECTIVES: To determine the efficacy of low protein diets in delaying the need to start maintenance dialysis. SEARCH STRATEGY: Cochrane Renal Group trials register, the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE. Congress abstracts (American Society of Nephrology since 1990, European Dialysis Transplant Association since 1985, International Society of Nephrology since 1987). Direct contacts with investigators. Date of most recent search: December 2004. SELECTION CRITERIA: Randomised trials comparing two different levels of protein intake in adult patients suffering from moderate to severe renal failure, followed for at least one year. DATA COLLECTION AND ANALYSIS: Two reviewers independently selected studies and extracted data. Statistical analyses were performed using the random effects model and the results expressed as relative risk (RR) for dichotomous outcomes with 95% confidence intervals (CI). Collection of the number of "renal deaths" defined as the need for starting dialysis, the death of a patient or a kidney transplant during the trial. MAIN RESULTS: Eight trials were identified from over 40 studies. A total of 1524 patients were analysed, 763 had received reduced protein intake and 761 a higher protein intake. Two hundred and fifty one renal deaths were recorded, 103 in the low protein diet and 148 in the higher protein diet group (RR 0.69, 95% CI 0.56 to 0.86, P = 0.0007). To avoid one renal death, 2 to 56 patients need to be treated with a low protein diet during one year. AUTHORS' CONCLUSIONS: Reducing protein intake in patients with chronic kidney disease reduces the occurrence of renal death by 31% as compared with higher or unrestricted protein intake. The optimal level of protein intake cannot be confirmed from these studies.

Structure and function of cationic amino acid transporters (CATs).

The CAT proteins (CAT for cationic amino acid transporter) are amongst the first mammalian amino acid transporters identified on the molecular level and seem to be the major entry path for cationic amino acids in most cells. However, CAT proteins mediate also efflux of their substrates and thus may also deplete cells from cationic amino acids under certain circumstances. The CAT proteins form a subfamily of the solute carrier family 7 (SLC7) that consists of four confirmed transport proteins for cationic amino acids: CAT-1 (SLC7A1), CAT-2A (SLC7A2A), CAT-2B (SLC7A2B), and CAT-3 (SLC7A3). SLC7A4 and SLC7A14 are two related proteins with yet unknown function. One focus of this review lies on structural and functional differences between the different CAT isoforms. The expression of the CAT proteins is highly regulated on the level of transcription, mRNA stability, translation and subcellular localization. Recent advances toward a better understanding of these mechanisms provide a second focus of this review.

Phosphodiesterase III inhibitors for heart failure.

BACKGROUND: In the treatment of chronic heart failure, vasodilating agents, ACE inhibitors and beta-blockers have shown an increase of life expectancy. Another strategy is to increase the inotropic state of the myocardium : phosphodiesterase inhibitors (PDIs) act by increasing intra-cellular cyclic AMP, thereby increasing the concentration of intracellular calcium, and lead to a positive inotropic effect. OBJECTIVES: This overview on summarised data aims to review the data from all randomised controlled trials of PDIs III versus placebo in symptomatic patients with chronic heart failure. The primary endpoint is total mortality. Secondary endpoints are considered such as cause-specific mortality, worsening of heart failure (requiring intervention), myocardial infarction, arrhythmias and vertigos. We also examine whether the therapeutic effect is consistent in the subgroups based on the use of concomitant vasodilators, the severity of heart failure, and the type of PDI derivative and/or molecule. This overview updates our previous meta-analysis published in 1994. SEARCH STRATEGY: Randomised trials of PDIs versus placebo in heart failure were searched using MEDLINE (1966 to 2004 January), EMBASE (1980 to 2003 December), Cochrane CENTRAL trials (The Cochrane Library Issue 1, 2004) and McMaster CVD trials registries, and through an exhaustive handsearching of international abstracting publications (abstracts published in the last 22 years in the "European Heart Journal", the "Journal of the American College of Cardiology" and "Circulation"). SELECTION CRITERIA: All randomised controlled trials of PDIs versus placebo with a follow-up duration of more than three months. DATA COLLECTION AND ANALYSIS: 21 trials (8408 patients) were eligible for inclusion in the review. 4 specific PDI derivatives and 8 molecules of PDIs have been considered. MAIN RESULTS: As compared with placebo, treatment with PDIs was found to be associated with a significant 17% increased mortality rate (The relative risk was 1.17 (95% confidence interval 1.06 to 1.30; p<0.001). In addition, PDIs significantly increase cardiac death, sudden death, arrhythmias and vertigos. Considering mortality from all causes, the deleterious effect of PDIs appears homogeneous whatever the concomitant use (or non-use) of vasodilating agents, the severity of heart failure, the derivative or the molecule of PDI used. AUTHORS' CONCLUSIONS: Our results confirm that PDIs are responsible for an increase in mortality rate compared with placebo in patients suffering from chronic heart failure. Currently available results do not support the hypothesis that the increased mortality rate is due to additional vasodilator treatment. Consequently, the chronic use of PDIs should be avoided in heart failure patients.

Planning of clinical trials.

This article focuses on steps of planning clinical trials most relevant to the question the clinician asks and how this question is properly transformed in a design and a protocol. All steps are important for the data quality or the validity of the results. A clinical trial is an experiment aimed at testing an hypothesis regarding the efficacy of a given intervention on an event, symptom or impaired quality of life in patients with a defined condition and a particular profile. As such, it should meet the fundamentals of scientific discovery that guarantee causality between the observed difference and the intervention. All the planning components are thought according to these fundamentals.

Level of evidence as a future gold standard for the content quality of health resources on the internet.

OBJECTIVE: An assessment of the quality of health information on the Internet is an absolute necessity. In this study 'sensitive' information was defined as information found in documents published on the Internet, which could be used in a medical decision. For sensitive information, the main criterion chosen for the quality of the information was an indication of the level of evidence. A survey was conducted using the CISMeF health catalogue to assess how often a score of the level of evidence is mentioned in the information accessible on the Internet in French-language health resources. METHODS: Since 1999, members of the CISMeF team have systematically been searching for all documents containing 'sensitive' information and verifying whether the level of evidence was explicitly indicated as a score at least once in the document. RESULTS: As of June 2001, 10,190 resources were included in CISMeF; including 2964 textual 'sensitive' resources (29.1%). Out of all these resources, only 4.7% (95% confidence interval: 4.0 - 5.5%) indicated the level of evidence. A statistically significant difference in the prevalence of indicating the level of evidence according to resource types (e.g., 18.1% for guidelines compared to 0.0% for teaching material), year of publication (almost three times greater in 1997-2001 compared with 1990-1996) and publishers was observed. CONCLUSION: As the number of people accessing the growing amount of information on the Internet is increasing daily, publishers have an ethical obligation to inform their readers about the validity of 'sensitive' information their sites contain. However, the vast majority of the French language Internet resources that were surveyed do not mention a score of the level of evidence for their sensitive information.

[Identification, during development, of a methodology targeted at determining the positioning of new drugs for therapeutic strategies: examples of rheumatoid arthritis and cardiac insufficiency]. / Identification, lors du développement, d'une méthodologie pour déterminer la place des nouveaux médicaments dans les stratégies thérapeutiques: exemples de la polyarthrite rhumatoïde et de l'insuffisance cardiaque.

The Marketing Authorization (MA) granted to a new molecular entity does not allow for proper anticipation of its future positioning within the therapeutic strategy. A specific methodology should be devised as early as during the pre-MA development phase that could result in an initial positioning that should be subjected to further reappraisal with regard to scientific advances, the arrival of new treatments and further developments with this molecule. A methodology is thus proposed, based on early optimisation of the development plan, the granting of subsequent MAs, and reappraisal of the positioning within the strategy, based on analysis of all available data. It should be possible to take into account the economic context, within an agreed system with pre-defined medico-economic criteria. This may in turn raise the issue of the role of the various parties involved in this assessment, as well as how to understand the respective opinions of stakeholders: authorities, sponsors, prescribers and patients, each of whom has a specific view of the definition of the strategic objective that should apply to the disease concerned.

Persistent asthma: disease control, resource utilisation and direct costs.

Despite evidence that adverse outcomes are less frequent when asthma management is optimised, the link between the level of control, disease severity and medical resource utilisation (MRU) is poorly documented. This relationship was investigated in a group of patients suffering from persistent asthma (Global Initiative for Asthma (GINA) > or = 2) in France. In 1998 a computerised family practice database was used to identify asthma patients aged 17-50 yrs. Information from the database was complemented by a patient survey to retrospectively assess the level of asthma control and hospital contacts. Costs of MRU over a 12-month study period were related to demographics, medical history, asthma control, and doses of inhaled corticosteroids prescribed during the prestudy period. A review of the computerised medical database identified 1,038 adult patients with persistent asthma, who completed the survey questionnaire. Over a 12-month period, the mean cost of MRU was 549.8 euros for well-controlled patients, 746.3 euros per patient with moderate control, and 1,451.3 euros per patient with poor control. Costs also increased significantly with age, access to free asthma care, comorbid conditions, asthma symptoms in the past year and whether inhaled corticosteroids had been prescribed before the study period. In patients with persistent asthma, large differences were observed in the use of medical resources according to control and severity. Therefore, if patients appropriately use prescribed control therapy, their use of medical resources may be reduced.

Terbinafine in fungal infections of the nails: a meta-analysis of randomized clinical trials.

BACKGROUND: Historically, there has been a general resistance to treating onychomycosis on the basis that such treatments were protracted and of uncertain outcome. However, modern treatments act more promptly and reliably. OBJECTIVES: To carry out a meta-analysis to evaluate the efficacy and safety of terbinafine in comparison with placebo, itraconazole and griseofulvin. METHODS: The analysis used data from published trials, supplemented where necessary by reference to the original trial reports. RESULTS: Three trials were included in which terbinafine was compared with placebo. From four trials comparing terbinafine with itraconazole, a statistically significant advantage in favour of terbinafine was observed for negative culture and microscopy at the end of the trials. Furthermore, both patients and physicians reported terbinafine to be better tolerated than itraconazole. From two trials comparing terbinafine with griseofulvin, a significantly higher rate of negative microscopy and culture was observed with terbinafine. CONCLUSIONS: A significant advantage in favour of treatment with terbinafine was observed.

Involvement of PKC and NF-kappaB in nitric oxide induced apoptosis in human coronary artery smooth muscle cells.

Apoptosis of vascular smooth muscle cells is critically involved in progression of atherosclerosis and may prevent intimal hyperplasia in restenosis and vascular remodeling. Nitric oxide (NO) is known to induce apoptosis, but the signaling pathways still remain unclear. We investigated p53 accumulation, protein kinase C (PKC) activation and nuclear transcription factor (NF-kappaB) binding activity as possible signaling mechanisms of NO-induced apoptosis. Apoptosis was induced dose-dependently with the NO-donors sodiumnitroprusside (SNP: 232+/-48%) and SIN-1 (241+/-90% of actinomycin D induced apoptosis; means +/- SEM, *p< or =0.05 vs. control) in HSMC. Inhibition of PKC significantly attenuated NO-induced apoptosis. Staurosporine reduced SIN-1/SNP-mediated DNA fragmentation by 55.3+/-13.8% and 38.3+/-13.9% respectively. Comparable results were obtained for calphostin C. However, NO-mediated induction of apoptosis was not preceded by p53 accumulation. SNP decreased NF-kappaB binding activity in HSMC. These results suggest that induction of apoptosis by exogenous NO in HSMC is not dependent on p53 accumulation but involves protein kinase C signaling and regulation of NF-kappaB binding activity. This opens a new therapeutical approach in preventing restenosis after angioplasty.

Human cationic amino acid transporter hCAT-3 is preferentially expressed in peripheral tissues.

At least five distinct carrier proteins form the family of mammalian cationic amino acid transporters (CATs). We have cloned a cDNA containing the complete coding region of human CAT-3. hCAT-3 is glycosylated and localized to the plasma membrane. Transport studies in Xenopus laevis oocytes revealed that hCAT-3 is selective for cationic L-amino acids and exhibits a maximal transport activity similar to other CAT proteins. The apparent substrate affinity and sensitivity to trans-stimulation of hCAT-3 resembles most closely hCAT-2B. This is in contrast to rat and murine CAT-3 proteins that have been reported to display a very low activity and to be inhibited by neutral and anionic L-amino acids as well as D-arginine (Hosokawa, H., et al. (1997) J. Biol. Chem. 272, 8717-8722; Ito, K., and Groudine, M. (1997) J. Biol. Chem. 272, 26780-26786). Also, in adult rat and mouse, CAT-3 has been found exclusively in central neurons. Human CAT-3 expression is not restricted to the brain, in fact, by far the highest expression was found in thymus. Also in other peripheral tissues, hCAT-3 expression was equal to or higher than in most brain regions, suggesting that hCAT-3 is not a neuron-specific transporter.