Gene Therapy: A Possible Alternative to CFTR Modulators?

Cystic fibrosis (CF) is a rare genetic disease that affects several organs, but lung disease is the major cause of morbidity and mortality. The gene responsible for CF, the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene, has been discovered in 1989. Since then, gene therapy i.e., defective gene replacement by a functional one, remained the ultimate goal but unfortunately, it has not yet been achieved. However, patients care and symptomatic treatments considerably increased CF patients' life expectancy ranging from 5 years old in the 1960s to 40 today. In the last decade, research works on CFTR protein structure and activity led to the development of new drugs which, by readdressing CFTR to the plasma membrane (correctors) or by enhancing its transport activity (potentiators), allow, alone or in combination, an improvement of CF patients' lung function and quality of life. While expected, it is not yet known whether taking these drugs from an early age and for years will improve the quality of life of CF patients in the long term and further increase their life expectancy. Besides, these molecules are not available (specific variants of CFTR) or accessible (national health policies) for all patients and there is still no curative treatment. Another alternative that could benefit from new technologies, such as gene therapy, is therefore still attractive, although it is not yet offered to patients. Faced with the development of new CFTR correctors and potentiators, the question arises as to whether there is still a place for gene therapy and this is discussed in this perspective.

[SLC6A14, a modifier gene in cystic fibrosis]. / SLC6A14, un gène modificateur dans la mucoviscidose.

Although cystic fibrosis is a monogenic disease, a considerable clinical phenotypic variability is observed in patients with the same CFTR mutations. Thanks to the development of new and powerful tools for carrying out genetic studies, several genes called "modifier genes" have been identified as being associated with the severity of the lung function disorder in cystic fibrosis patients. Among these genes, SLC6A14 may modulate the anti-infective response and epithelial integrity of the airways, thus providing a potential therapeutic target to improve the patient's lung function.

Disparate results between proliferation rates of surgically excised prostate tumors and an in vitro bioassay using sera from a positive randomized controlled trial.

In vitro bioassay has been used extensively to test the effects of culturing cancer cells in sera from humans participating in dietary interventions, i.e, studies of modified intake of nutrients for the purpose of reducing cancer risk or progression. It has been hypothesized that cell proliferation rates determined by the in vitro bioassay indicate whether modification of dietary intake could decrease cancer cell growth in vivo. It has been suggested, however, that the in vitro bioassay may not correlate with tumor cell proliferation rates in prostate cancer. We investigated the concordance of cell proliferation rates from surgically excised prostate tumor tissue with the in vitro bioassay using sera from matched patients. We used samples from an earlier randomized clinical trial that showed that supplementation with flaxseed significantly inhibited prostate cancer cell proliferation rates in vivo as indicated by Ki67 staining in tumor specimens. Proliferation rates of LNCaP, DU145 and PC3 cell lines cultured in 10% human sera from participants in the flaxseed trial were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Spearman's Rho correlation coefficients (ρ) indicated no association between Ki67 staining in prostate tumors and the in vitro bioassay for the three cell lines. These disparate findings suggest that the in vitro bioassay may not provide an accurate assessment of the environment in vivo.

Repurposing the open access malaria box to discover potent inhibitors of Toxoplasma gondii and Entamoeba histolytica.

Toxoplasmosis and amebiasis are important public health concerns worldwide. The drugs currently available to control these diseases have proven limitations. Therefore, innovative approaches should be adopted to identify and develop new leads from novel scaffolds exhibiting novel modes of action. In this paper, we describe results from the screening of compounds in the Medicines for Malaria Venture (MMV) open access Malaria Box in a search for new anti-Toxoplasma and anti-Entamoeba agents. Standard in vitro phenotypic screening procedures were adopted to assess their biological activities. Seven anti-Toxoplasma compounds with a 50% inhibitory concentration (IC50) of <5 µM and selectivity indexes (SI) of >6 were identified. The most interesting compound was MMV007791, a piperazine acetamide, which has an IC50 of 0.19 µM and a selectivity index of >157. Also, we identified two compounds, MMV666600 and MMV006861, with modest activities against Entamoeba histolytica, with IC50s of 10.66 µM and 15.58 µM, respectively. The anti-Toxoplasma compounds identified in this study belong to scaffold types different from those of currently used drugs, underscoring their novelty and potential as starting points for the development of new antitoxoplasmosis drugs with novel modes of action.

Pasireotide versus octreotide in acromegaly: a head-to-head superiority study.

CONTEXT: Biochemical control reduces morbidity and increases life expectancy in patients with acromegaly. With current medical therapies, including the gold standard octreotide long-acting-release (LAR), many patients do not achieve biochemical control. OBJECTIVE: Our objective was to demonstrate the superiority of pasireotide LAR over octreotide LAR in medically naive patients with acromegaly. DESIGN AND SETTING: We conducted a prospective, randomized, double-blind study at 84 sites in 27 countries. PATIENTS: A total of 358 patients with medically naive acromegaly (GH >5 µg/L or GH nadir ≥1 µg/L after an oral glucose tolerance test (OGTT) and IGF-1 above the upper limit of normal) were enrolled. Patients either had previous pituitary surgery but no medical treatment or were de novo with a visible pituitary adenoma on magnetic resonance imaging. INTERVENTIONS: Patients received pasireotide LAR 40 mg/28 days (n = 176) or octreotide LAR 20 mg/28 days (n = 182) for 12 months. At months 3 and 7, titration to pasireotide LAR 60 mg or octreotide LAR 30 mg was permitted, but not mandatory, if GH ≥2.5µg/L and/or IGF-1 was above the upper limit of normal. MAIN OUTCOME MEASURE: The main outcome measure was the proportion of patients in each treatment arm with biochemical control (GH <2.5 µg/L and normal IGF-1) at month 12. RESULTS: Biochemical control was achieved by significantly more pasireotide LAR patients than octreotide LAR patients (31.3% vs 19.2%; P = .007; 35.8% vs 20.9% when including patients with IGF-1 below the lower normal limit). In pasireotide LAR and octreotide LAR patients, respectively, 38.6% and 23.6% (P = .002) achieved normal IGF-1, and 48.3% and 51.6% achieved GH <2.5 µg/L. 31.0% of pasireotide LAR and 22.2% of octreotide LAR patients who did not achieve biochemical control did not receive the recommended dose increase. Hyperglycemia-related adverse events were more common with pasireotide LAR (57.3% vs 21.7%). CONCLUSIONS: Pasireotide LAR demonstrated superior efficacy over octreotide LAR and is a viable new treatment option for acromegaly.

Development of exchange lists for Mediterranean and Healthy Eating diets: implementation in an intervention trial.

BACKGROUND: There has been little research published on the adaptation of diabetic exchange list diet approaches for the design of intervention diets in health research despite their clinical utility. The exchange list approach can provide clear and precise guidance on multiple dietary changes simultaneously. The present study aimed to develop exchange list diets for Mediterranean and Healthy Eating, and to evaluate adherence, dietary intakes and markers of health risks with each counselling approach in 120 subjects at increased risk for developing colon cancer. METHODS: A randomised clinical trial was implemented in the USA involving telephone counselling. The Mediterranean diet had 10 dietary goals targeting increases in mono-unsaturated fats, n-3 fats, whole grains and the amount and variety of fruits and vegetables. The Healthy Eating diet had five dietary goals that were based on the US Healthy People 2010 recommendations. RESULTS: Dietary compliance was similar in both diet arms, with 82-88% of goals being met at 6 months, although subjects took more time to achieve the Mediterranean goals than the Healthy Eating goals. The relatively modest fruit and vegetable goals in the Healthy Eating arm were exceeded, resulting in fruit and vegetable intakes of approximately eight servings per day in each arm after 6 months. A significant (P < 0.05) weight loss and a decrease in serum C-reactive protein concentrations were observed in the overweight/obese subgroup of subjects in the Mediterranean arm in the absence of weight loss goals. CONCLUSIONS: Counselling for the Mediterranean diet may be useful for both improving diet quality and for achieving a modest weight loss in overweight or obese individuals.

Modelling of bioassay data from a Pu wound treated by repeated DTPA perfusions: biokinetics and dosimetric approaches.

The aim of this study is to model plutonium (Pu) excretion from the analysis of a well-documented Pu wound case involving repeated diethylene-triamine-penta-acetic acid (DTPA) perfusions up to 390 d and monitoring up to 3109 d. Three modelling approaches were simultaneously applied involving: (1) release of soluble Pu from the wound, estimated with the ICRP66 dissolution model, (2) systemic behaviour of Pu by using ICRP67 model, but also two new models recently reported and (3) additional 'Pu-DTPA' compartments which transfer Pu directly to urinary compartment from blood, interstitial fluids and liver. The best fit of simulations to biological data was obtained by using the new Leggett's systemic model and assuming the presence of three DTPA compartments. Calculations have shown that DTPA treatments have contributed to a 3-fold reduction of the effective dose. Thus, reduction of doses associated with the DTPA treatments can be estimated by modelling which is useful to improve the efficacy of a DTPA treatment schedule based on a diminution of risk.

High vegetable and fruit diet intervention in premenopausal women with cervical intraepithelial neoplasia.

OBJECTIVE: To examine whether diet intervention can promote increased vegetable and fruit intake, as reflected in increased plasma carotenoid and decreased plasma total homocysteine concentrations, in premenopausal women with cervical intraepithelial neoplasia, a precancerous condition. DESIGN: Randomized controlled diet intervention study. SUBJECTS: Fifty-three free-living premenopausal women who had been diagnosed with cervical intraepithelial neoplasia, were randomly assigned to an intervention (n = 27) or a control (n = 26) group. INTERVENTION: Individualized dietary counseling to increase vegetable and fruit intake. MAIN OUTCOME MEASURES: Diet was assessed by food frequency questionnaire. Plasma carotenoids and total homocysteine were measured at enrollment and at 6 months follow up. ANALYSIS: Associations between baseline plasma concentrations of carotenoids and homocysteine and influencing factors were examined with multiple regression analysis. Repeated measures analysis of variance was used to test for group by time effects in these plasma concentrations. Plasma carotenoids at baseline and 6 months in the study groups, and differences in homocysteine concentrations from baseline to 6 months, were compared with independent sample t tests. RESULTS: Repeated measures analysis of variance showed significant group by time effects (P<.01) in plasma carotenoid and homocysteine concentrations. In the intervention group, total plasma carotenoids increased by an average of 91%, from 2.04+/-0.13 (mean+/-standard error of the mean) to 3.90+/-0.56 micromol/L and plasma total homocysteine was reduced by 11%, from 9.01+/-0.40 to 8.10+/-0.44 micromol/L (P<.003). Neither changed significantly in the control group. APPLICATIONS: Individualized dietary counseling can effectively promote increased vegetable and fruit intake in premenopausal women. This dietary pattern may reduce risk for cancer and other chronic diseases and also promote an improvement in folate status.

Do antioxidants still have a role in the prevention of human cancer?

Antioxidants are components of diet that are involved in DNA and cell maintenance and repair. Dietary antioxidants include carotenoids, vitamin C, vitamin E, and selenium. Across a variety of cancers, the observational studies have inconsistent results with respect to the relationship shown of specific dietary intake or serum levels of antioxidants and risk of certain cancers. The results of the micronutrient supplement trials clearly do not support a reductionist approach to promoting regression of precancerous lesions or prevention of new cancer, except in a few cancers and specific populations. The ability of the antioxidant micronutrients to influence the risk for tissue injury and for cancer, mediated by their antioxidant activities, remains hypothetical.

Colonic mucosal prostaglandin E2 and cyclooxygenase expression before and after low aspirin doses in subjects at high risk or at normal risk for colorectal cancer.

UNLABELLED: Development of potential cancer chemopreventive drugs involves the systematic evaluation of these drugs in preliminary Phase I and II studies in human beings to identify the optimal drug dose, drug toxicity, and surrogate end point biomarker modulation. OBJECTIVES: We tested the hypothesis that aspirin, at a single, once-daily 81-mg dose, will reduce colonic mucosal concentration of prostaglandin estradiol (E2) in individuals at high risk for colorectal cancer development similar to our prior observations in a young normal-risk population. METHODS: Aspirin was administered at a dose of 81 mg once daily for 28 days in a cohort of 92 matched high-risk and normal-risk colorectal cancer subjects. Prostaglandin E2 and cyclooxygenase expression were assayed from distal sigmoid biopsies from all of the subjects before and after treatment. RESULTS: The mean prostaglandin E2 for normal-risk subjects before aspirin treatment was 11.3 +/- 1.7 pg/microg (mean +/- SE) tissue protein and after aspirin treatment was 4.9 +/- 0.91 pg/microg tissue protein (P < 0.0001). In high-risk subjects, mean pretreatment prostaglandin E2 was 14.4 +/- 1.7 pg/microg tissue protein and after aspirin treatment was 4.7 +/- 0.70 pg/microg tissue protein (P < 0.0001). Aspirin treatment did not alter cyclooxygenase-1 protein expression. CONCLUSIONS: Aspirin treatment at a dose of 81 mg reduces colorectal mucosal prostaglandin E2 concentration after 28 daily doses. Risk for colorectal carcinoma did not modify colorectal mucosal baseline or post-aspirin prostaglandin E2, or cyclooxygenase expression. Colorectal mucosal prostaglandin concentration may be used as a "drug-effect surrogate biomarker," that is, a surrogate to assess sufficient delivery and tissue effect of a chemopreventive agent.

Intracerebroventricular injection of murine leptin enhances the postprandial metabolic rate in the rat.

Energy balance is achieved by means of a concomitant control of both food intake and energy expenditure. Leptin, synthesized in the adipose tissue, acts on brain structures and lowers body weight by inhibiting food intake and in parallel by enhancing energy expenditure i.e. metabolism or one of its components. Recording distinctly these components allowed us to assess the effect of an acute intracerebroventricular injection of leptin on both feeding pattern and background metabolism (i.e. energy expenditure free from the part of locomotor activity), respiratory quotient, feeding-related metabolism and locomotor activity-related metabolism. Leptin injection to Sprague-Dawley male rats induced an inhibition of feeding that began 90 min after the treatment and lasted 1 h before to return to the control feeding pattern level. Considering this late behavioral effect, it appeared that leptin may act during the postprandial period so that we recorded the different metabolic parameters following a 3 g calibrated meal itself preceded by leptin vs. artificial cerebrospinal fluid injection. Postprandial respiratory quotient was rapidly lowered in leptin-treated animals and subsequent background metabolism increased for 6 h. Thus it appeared that leptin increased the duration of the postprandial metabolic rate via the recruitment of endogenous fat stores. Enhancement in the thermic effect of food may be the reason for feeding behavior inhibition to be delayed.

Prevention of cervix cancer.

Cervix carcinoma is an important health problem world-wide, being the second most common cancer among women, ranking first in many developing countries. A number of important epidemiological risk factors have been identified as contributing to the development of CIN and invasive cervix carcinoma. Of key importance is infection with human papillomavirus (HPV), which is the primary risk factor. There are evolving primary and secondary preventive strategies that could further reduce the burden from cervical carcinoma. The possible primary preventive strategies include risk reduction, diet or dietary supplements, HPV vaccines, and other chemopreventive agents. The possible advances in secondary preventive strategies include new technologies for Pap smears, HPV typing triage, and other adjuvant screening procedures. The impact of these strategies will depend upon evidence to support their use along with the characteristics of the population and environment in which they are used.

Building a framework to transform health care.

Advances in information technology are helping clinicians to realize the promise of evidence-based medicine, which includes benchmarking, outcomes monitoring, predictive modeling, and clinical pathways. By integrating individual clinical expertise and the best available research, physicians can apply the disciplines and techniques of clinical research to their practice of medicine, one patient at a time. Evidence-based medicine also allows organizations to move forward with continuous clinical quality improvement programs. Standards, open systems, data warehouses, and evidence-based medicine help a health care delivery system obtain the technical infrastructure, decision-making processes, analytical skills, clinical databases, predictive models, and clinical pathways. With this information technology (1) physicians can practice evidence-based medicine and (2) the delivery system can profile clinicians' practice habits for managed care contracting and continuous clinical quality improvement.

Recruiting subjects in cancer prevention and control studies.

Recruitment of subjects is a critical aspect of prevention trials that is often overlooked by investigators. As a consequence, accrual time is often extended, workloads may become heavy, and resource utilization is increased in an effort to complete projects. Recruitment of healthy subjects in cancer prevention and control studies presents unique issues that need to be considered. The barriers to recruitment include participant issues, physician variables, features of the study design, and characteristics of the health care system in the United States. The authors provide their experience in overcoming these difficulties.

Predictors of screening for breast, cervical, colorectal, and prostatic cancer among community-based primary care practices.

BACKGROUND: As we enter the year 2000, it is worth looking at whether primary care practices are reaching the goals established in Healthy People 2000 for breast, cervical, colorectal, and prostatic cancer screening. The objectives of this study were (1) to determine the current rates of cancer screening; and (2) to determine which factors predict completion of a single screening test, of all tests for each cancer, and of all procedures for age and sex. METHODS: Medical records of 200 eligible patients (100 men and 100 women) from each of 24 community-based primary care practices were abstracted for cancer-screening events. RESULTS: We audited 5125 charts. A Papanicolaou smear was documented for 63.8% of women with an intact cervix within 3 years of the audit.. We found that 46.8% of women had documentation of ever having a discussion of breast self-examination. For breast cancer screening, 41.8% of the women had a clinical breast examination within 1 year, 48.2% aged 40 to 49 years had a mammogram within 2 years, and 38.5% aged 50 years and older had a mammogram within 1 year. Only 29% of women aged 40 to 49 years and 17% of women 50 years and older were current for all breast cancer-screening tests. Among patients 50 years and older, 33% of men and 38% of women had a digital rectal examination within 1 year, 26% of men and 28% of women had a fecal occult blood test within 1 year, and 22% of men and 16.8% of women had a flexible sigmoidoscopy within 5 years. Of all men 28.7% had a prostate-specific antigen test within 1 year. Completion of all tests relevant for age and sex were documented for 8.6% of women aged 40 to 49 years, 3% of women 50 years and older, and 5% of men 50 years and older. The single most significant predictor of documented cancer screening was a health maintenance visit. CONCLUSIONS: This sample of primary care clinicians has not reached the goals set in Healthy People 2000 for cancer screening. Interventions aimed at increasing the percentage of patients who schedule a health maintenance visit could serve to increase cancer screening and help us reach goals set for the year 2010.

Genetic taste markers and preferences for vegetables and fruit of female breast care patients.

OBJECTIVE: To explore links between genetic responsiveness to the bitter taste of 6-n-propylthiouracil (PROP) and self-reported preferences for vegetables and fruit of female breast care patients. METHODS: PROP tasting was defined by detection thresholds and by perceived bitterness and hedonic ratings for PROP solutions. Nontasters, medium tasters, and supertasters were identified by their PROP thresholds and by the ratio of perceived bitterness of PROP to the perceived saltiness of sodium chloride solutions. Subjects rated preferences for vegetables and fruit using 9-point category scales. SUBJECTS/SETTING: A clinical sample of 170 patients with newly diagnosed breast cancer and 156 cancer-free control subjects were recruited from the University of Michigan Breast Care Center. STATISTICAL ANALYSES: Principal components factor analysis, one-way analyses of variance, and Pearson correlations and chi 2 tests were used to analyze taste and food preference data. RESULTS: Genetic responsiveness to PROP was associated with lower acceptance of cruciferous and selected green and raw vegetables (P < .05). Women who reported disliking such foods were medium tasters or supertasters of PROP. Preference ratings for fruit were unrelated to PROP taster status. APPLICATIONS/CONCLUSIONS: Women who are PROP tasters may be less likely to comply with dietary strategies for cancer prevention that emphasize consumption of cruciferous vegetables and bitter salad greens. Alternatively, PROP-sensitive women may seek to reduce bitter taste by adding fat, sugar, or salt.

Electrical stimulation of the ventromedial hypothalamus enhances both fat utilization and metabolic rate that precede and parallel the inhibition of feeding behavior.

The effects of ventromedial hypothalamic (VMH) stimulation on various metabolic parameters in freely moving animals were measured using a specific indirect calorimetric chamber associated with a quantitative measurement of locomotor activity, which allows the separate measurement of locomotor energy expenditure from that of background metabolism, BM (free from expenses due to locomotion). To obtain circumscribed VMH stimulation, a slight-intensity (20-25 microA) bipolar, constant current was applied for 15 min at the beginning of the dark phase on ad libitum fed rats. The VMH stimulation suppressed feeding for 40 min, then animals progressively recovered within the subsequent 60 min as shown by comparison with the control group. On different days, the same stimulation parameters were applied while food was unavailable, and metabolic parameters were recorded. An increase in BM lasting 30 min was observed. This increase in metabolic rate was sustained by means of a recruitment of lipid stores as indicated by a concomitant drop in respiratory quotient. These observations indicate that the VMH is part of the sympathetic nervous system, capable of inducing lipolysis. The sequence of metabolic and feeding events may then in part be due to VMH-induced lipolysis that provides more fuel to the metabolic economy, raising the BM, which in turn decreases hunger.

The psychosexual impact of human papillomavirus cervical infections.

BACKGROUND: Occult human papillomavirus (HPV) infection, present in approximately 20% of women in the United States, is usually sexually transmitted, associated with substantial health risks, and unpredictable in its resolution. The potential for adverse psychosexual alterations due to HPV infection in women considered at low risk for bacterial sexually transmitted diseases is substantial, but data is lacking. METHODS: This cross-sectional study was conducted with sexually active women aged 18 to 60 years who had been enrolled at community-based offices in the University of Michigan Vaginitis Study. Women found to have occult HPV infection of the cervix were notified, received physician consultation, and were encouraged to have colposcopy performed to assess lesion status. Responses to a follow-up written questionnaire for differences in psychosexual functioning and attitudes following diagnosis were compared among these women and those without HPV infection. RESULTS: The women enrolled were primarily white and had a current sexual partner at the time of enrollment. They had few sexually transmitted infections and few risk factors, yet 20% had unsuspected HPV infection. Psychosexual characteristics at baseline and at follow-up, as well as perceived changes in these characteristics by the women, did not differ between women with HPV infection and those without. Stratification by potential confounders, including the presence of a vaginal infection at the time of study enrollment, household income level, ethnic background, age, marital status, and sexual history, did not alter these results. CONCLUSIONS: Women at low risk for sexually transmitted diseases, but who had a cervical HPV infection, were similar to those not infected in reported psychosexual characteristics and functioning. Adverse changes in these characteristics between the time of the diagnosis and subsequent follow-up were no more likely in those with the diagnosis than in those without.