Genetic variation in UGT1A1 is not associated with altered liver biochemical parameters in healthy volunteers participating in bioequivalence trials

Introduction: Bioequivalence clinical trials are conducted in healthy volunteers whose blood tests should be within normal limits; individuals with Gilbert syndrome (GS) are excluded from these studies on suspicion of any liver disease, even if the change is clinically insignificant. GS is a benign genetic disorder characterized by elevated bilirubin levels, the primary cause of which is the presence of polymorphisms in UGT1A1 gene. In this work, subjects with UGT1A1 intermediate (IM) or poor (PM) metabolizer genotype-informed phenotypes were investigated to determine whether they have a higher incidence of liver disease or other biochemical parameters. Methods: The study population comprised 773 healthy volunteers who underwent biochemical analysis at baseline and at the end of the study which were genotyped for UGT1A1*80 (rs887829), as an indicator of UGT1A1*80+*28 (rs887829 and rs3064744), and UGT1A1*6 (rs4148323). Results: Bilirubin levels were higher in subjects IMs and PMs compared to normal metabolizers (NMs). Decreased uric acid levels was observed in PMs compared to NMs. No associations were observed in liver enzyme levels according to UGT1A1 phenotype. Discussion: Considering that there is no hepatic toxicity in subjects with UGT1A1 IM or PM phenotype, who are more likely to develop GS, this study suggests that they could be included in bioequivalence clinical trials as their biochemical parameters are not affected outside normal ranges.

Effects of SARS-COVID-19 lockdown on menstrual patterns: A transversal large sample survey

OBJECTIVE

To elucidate the presence, importance, and characteristics of menstrual changes related to stressful circumstances during the COVID-19 lockdown in Spain.

STUDY DESIGN

An online survey was administered in Spain to menstruating women aged 15-55 who had not contracted COVID-19. It collected information on activities during the lockdown, sexual activity, perceptions of emotional status, any changes in menstrual characteristics, and impact on quality of life. The analysis of menstrual changes was limited to responders who did not use hormonal contraception.

RESULTS

A total of 6449 women answered the survey, and 4989 surveys were valid for the final analysis. 92.3% of women had at least one menstruation period during the lockdown, while 7.7% had amenorrhea. Quality of life (QoL) associated with menstruation worsened in 19% of women, did not change in 71.7%, and improved in 1.6%. For 50.1% of the women, global QoL worsened during the lockdown; 41.3% remained about the same and 8.7% reported improvement. Sexual activity during the lockdown decreased in 49.8% of the respondents, remained unchanged in 40.7%, and increased in 9.5%. As far the menstrual changes are concerned, there were no statistically significant differences in amenorrhea incidence, regularity of the menstrual cycle, or the amount or duration of menstrual bleeding in non-hormonal contraceptive users when evaluated by the length and characteristics of isolation, the perception of exposure to COVID-19 and the economic or employment situation. Conversely, we found statistically significant differences according to the intensity of changes in emotional status due to lockdown stressors and changes in regularity, duration, and heaviness of menstruation.

CONCLUSION

Changes in emotional status, but not the length and intensity of the isolation or exposure to the disease, significantly influenced menstrual disturbances during the COVID-19 lockdown.

Pharmacogenetic biomarkers for secukinumab response in psoriasis patients in real-life clinical practice

BACKGROUND

Prediction of the response to a biological treatment in psoriasis patients would allow efficient treatment allocation.

OBJECTIVE

To identify polymorphisms associated with secukinumab response in psoriasis patients in a daily practice setting.

METHODS

We studied 180 SNPs in patients with moderate-to-severe plaque psoriasis recruited from 15 Spanish hospitals. Treatment effectiveness was evaluated by absolute PASI ≤3 and ≤1 at 6 and 12 months. Individuals were genotyped using a custom Taqman array. Multiple logistic regression models were generated. Sensitivity, specificity and area under the curve (AUC) were analysed.

RESULTS

A total of 173 patients were studied at 6 months, (67% achieved absolute PASI ≤ 3 and 65% PASI ≤ 1) and 162 at 12 months (75% achieved absolute PASI ≤ 3 and 64% PASI ≤ 1). Multivariable analysis showed the association of different sets of SNPs with the response to secukinumab. The model of absolute PASI≤3 at 6 months showed best values of sensitivity and specificity. Four SNPs were associated with the capability of achieving absolute PASI ≤ 3 at 6 months. rs1801274 (FCGR2A), rs2431697 (miR-146a) and rs10484554 (HLCw6) were identified as risk factors for failure to achieve absolute PASI≤3, while rs1051738 (PDE4A) was protective. AUC including these genotypes, weight of patients and history of biological therapy was 0.88 (95% CI 0.83-0.94), with a sensitivity of 48.6% and specificity of 95.7% to discriminate between both phenotypes.

CONCLUSION

We have identified a series of polymorphisms associated with the response to secukinumab capable of predicting the potential response/non-response to this drug in patients with plaque psoriasis.

Preemptive TPMT Genotyping and Adherence to Genotype-Based Therapeutic Recommendations Reduces the Healthcare Cost in Patients Receiving Azathioprine or 6-Mercaptopurine for Autoimmune Diseases

A cost analysis of thiopurine treatment was carried out in 257 patients, with 153 preemptively genotyped for TPMT and 104 retrospectively genotyped in a Spanish setting. The healthcare cost was significantly higher in patients retrospectively genotyped compared to those who were preemptively genotyped (p < 0.001). TPMT intermediate metabolizers (IMs) (n = 23) showed a 3.3-fold higher healthcare cost when compared to normal metabolizers (NMs) (p < 0.001). The healthcare cost in patients with a TPMT IM phenotype whose physician adhered to the genotype-informed recommendation was similar than the cost in TPMT NMs and was significantly lower than IMs whose physician did not adhere to the therapeutic recommendation (3.8-fold, p = 0.016). Myelotoxicity occurrence was significantly lower in patients preemptively vs. retrospectively genotyped (2.0% and 21.2%, respectively, p < 0.001). Patients who developed myelotoxicity showed a significantly higher healthcare cost than those who did not (4.10-fold, p < 0.001). Overall, 87% of patients whose dose was not adjusted despite being TPMT IMs suffered myelotoxicity, while only one of the eight patients (13%) whose dose was adjusted suffered myelotoxicity (p < 0.001). In conclusion, TPMT preemptive genotyping and physician adherence to genotype-informed therapeutic recommendations prevents myelotoxicity and significantly reduces the healthcare cost, and it is therefore essential for the sustainability of the Spanish healthcare system.

Association between CYP2C19 and CYP2B6 phenotypes and the pharmacokinetics and safety of diazepam

Diazepam is a benzodiazepine (BZD) used worldwide for a variety of conditions. Long-term use of diazepam increases the risk for developing tolerance and dependence and for the occurrence of adverse drug reactions (ADRs). CYP3A4 and CYP2C19 mainly metabolize diazepam and are therefore the primary pharmacogenetic candidate biomarkers. In this work, we aimed to explore the impact of CYP3A4 and CYP2C19 phenotypes and of 99 additional variants in other 31 pharmacogenes (including other CYP, UGT, NAT2 and CES enzymes, ABC and SLC transporters) on diazepam pharmacokinetic variability and safety. 30 healthy volunteers that had participated in a single-dose bioequivalence clinical trial of two diazepam formulations were enrolled in the present candidate gene pharmacogenetic study. CYP2C19 poor metabolizers (PMs) showed an almost 2-fold increase in AUC_0-∞/DW compared to rapid (RMs) or normal (NM) metabolizers, and a 1.46-fold increase compared to intermediate metabolizers (IMs). CYP2B6 PMs showed a 2,74-fold higher AUC_0-∞/DW compared to RMs, and 2.10-fold compared to NMs (p < 0.007). A dose reduction of 25-50 % may be appropriate for CYP2C19 or CYP2B6 PMs to avoid ADRs, dependence and tolerance. Combined CYP2C19 +CYP2B6 PMs may not use diazepam or sharper dose adjustments (e.g., a dose reduction of 50-70 %) may be advisable. To our knowledge, this is the first work to report a strong relationship between CYP2B6 phenotype and diazepam pharmacokinetics. Additional nominal associations (i.e., 0.007 <p < 0.05) between ABCG2, ABCB1, NAT2 and UGT1A4 polymorphisms and pharmacokinetic variability were observed; further research should elaborate on the clinical relevance of the described associations.

Patients’ Perceptions of Pharmacogenetic Testing and Access to Their Results: State of the Art in Spain and Systematic Review

The process of clinical pharmacogenetics implementation depends on patients’ and general population’s perceptions. To date, no study has been published addressing Spanish patients’ opinions on pharmacogenetic testing, the availability of the results, and the need for signing informed consent. In this work, we contacted 146 patients that had been previously genotyped at our laboratory and 46 healthy volunteers that had participated in a bioequivalence clinical trial at the Clinical Pharmacology Department of Hospital Universitario de La Princesa and consented to pharmacogenetic testing for research purposes. From the latter, 108 and 34, respectively, responded to the questionnaire (i.e., a response rate of 74%); Participants were scheduled for a face-to-face, telephone, or videoconference interview and were asked a total of 27 questions in Spanish. Great or almost complete acceptance of pharmacogenetic testing was observed (99.3%), age and university education level being the main predictors of acceptance rates and understanding (multivariate analysis, p = 0.004, R2 = 0.17, age being inversely proportional to acceptance rates and understanding and university level being related to higher acceptance rates and understanding compared to other education levels). Mixed perceptions were observed on the requirement of written informed consent (55.6% in favor); therefore, it seems recommendable to continue requesting it for the upcoming years until more perceptions are collected. The majority of participants (95.8%) preferred storing pharmacogenetic results in medical records rather than in electronic sources (55.6%) and highly agreed with the possibility of carrying their results on a portable card (91.5%). Patients agreed to broad genetic testing, including biomarkers unrelated to their disease (93.7%) or with little clinically relevant evidence (94.4%). Patients apparently rely on clinician’s or pharmacogeneticist’s interpretation and seem, therefore, open to the generation of ethically challenging information. Finally, although most patients (68.3%) agreed with universal population testing, some were reluctant, probably due to the related costs and sustainability of the Spanish Health System. This was especially evident in the group of patients who were older and with a likely higher proportion of pensioners.

Effect on quality of life of switching to combined oral contraception based on natural estrogen: an observational, multicentre, prospective phase IV study (ZOCAL Study)

OBJECTIVES

This observational, multicentre, prospective phase IV study examined change in health-related quality of life (QOL) from baseline to 6 months in women initiating combined oral contraception (COC) based on natural estrogen.

METHODS

Eligible women attending a baseline and 6-month gynaecology appointment belonged to one of three groups: group 1 used barrier contraception (condoms) and elected to continue this method; group 2 used condoms and elected to switch to COC based on natural estrogen; group 3 used COC based on ethinylestradiol and elected to switch to COC based on natural estrogen. The Spanish Society of Contraception (SEC)-QOL scale assessed health-related QOL. Secondary outcomes included symptoms of premenstrual syndrome, intermenstrual bleeding, duration and intensity of menstrual bleeding, contraception continuation rate, and tolerability.

RESULTS

A total of 857 women were enrolled and 785 completed the study. Group 2 (n = 224 completed) had significantly lower SEC-QOL global and dimension scores at baseline and significantly greater increases in SEC-QOL from baseline to 6 months compared with groups 1 (n = 72) and 3 (n = 489). Group 3 reported a similar SEC-QOL score to that of group 1 at baseline but showed significantly greater improvement in SEC-QOL global and psychological scores from baseline to 6 months. Among women receiving COC based on natural estrogen, the contraception continuation rate was 713/780 (91.4%); treatment-related adverse events were reported by 13/780 (1.7%).

CONCLUSIONS

Improved SEC-QOL after 6 months was found in women who were dissatisfied with their current contraception at baseline and chose to switch to COC based on natural estrogen.

Effect of polymorphisms on the pharmacokinetics, pharmacodynamics, and safety of risperidone in healthy volunteers

OBJECTIVE

To identify genetic markers capable of predicting the pharmacokinetics, pharmacodynamics, and adverse effects of risperidone.

METHODS

Genotyping was performed in 70 healthy volunteers receiving a single 1mg oral dose of risperidone. Risperidone and hydroxyrisperidone plasma levels were measured using high-performance liquid chromatography combined with tandem mass spectrometry.Prolactin concentration was quantified by direct chemiluminescence.

RESULTS

Poor CYP2D6 metabolizers showed higher risperidone Cmax, area under the curve (AUC), and t1/2, as well as lower clearance. They also showed lower Cmax and AUC and higher t1/2 for hydroxyrisperidone. Furthermore, individuals with a mutant VKORC1 genotype had a lower risperidone AUC and t1/2 and higher clearance. The hydroxyrisperidone AUC was lower in individuals with the COMT mutant genotype. Risperidone increased prolactin levels (iAUC and iCmax), which were higher in women than in men. The most frequent reactions were somnolence (47.1%), headache (21.4%), and dizziness (17.1%). Women had neurological effects and headache more frequently than men. The incidence of headache was associated with polymorphisms in the AGTR1 and NAT2; neurological effects were associated with CYP2C19.

CONCLUSIONS

Differences in the pharmacokinetics of risperidone are due to polymorphisms in CYP2D6, COMT, and VKORC1. Differences in adverse reactions can be explained by gender and polymorphisms in CYP2C19, AGTR1, and NAT2.

Polymorphisms in CYP2D6 have a greater effect on variability of risperidone pharmacokinetics than gender

Within-subject coefficient of variation (CVw ) plays a decisive role in the determination of sample size in bioequivalence clinical trials. Highly variable drugs may require the participation of a large number of subjects. The aim of this study was to investigate whether gender and polymorphisms in CYP2D6 affect the CVw of risperidone. Two single-dose, two-period crossover studies of risperidone (n = 70) were reanalysed to calculate CVw for AUCt and Cmax . Subjects were classified into four different CYP2D6 phenotype groups [poor metabolizers (PM), intermediate metabolizers (IM), extensive metabolizers (EM) and ultrarapid metabolizers (UM)]. The effect of gender was evaluated in EM and IM. CVw was lower in PM (13.3% for AUCt and 10.9% for Cmax ) and UM (17.4% and 8.7%) than in EM (28.7% and 34.7%) and IM (33.2% and 27.3%). Variability was slightly lower in women (27.9% for AUCt and 25.7% for Cmax ) than in men (33.3% and 37.2%, respectively). Genetic polymorphisms affect within-subject variability more than gender and could considerably affect sample size calculation. Therefore, subjects participating in bioequivalence trials should be genotyped.

Nanomolar ouabain elicits apoptosis through a direct action on HeLa cell mitochondria

The steroid Na(+)/K(+) ATPase (NKA) blocker ouabain has been shown to exhibit pro-apoptotic effects in various cell systems; however, the mechanism involved in those effects is unclear. Here, we have demonstrated that incubation of HeLa cells during 24h with nanomolar concentrations of ouabain or digoxin causes apoptotic death of 30-50% of the cells. Ouabain caused the activation of caspases-3/7 and -9; however, caspase-8 was unaffected. The fact that compound Z-LEHD-FMK reduced both apoptosis and caspase-9 activation elicited by ouabain, suggest a mitochondrially-mediated pathway. This was strengthened by the fact that ouabain caused ATP depletion and the release of mitochondrial cytochrome c into the cytosol. Furthermore, upon ouabain treatment mitochondrial disruption and redistribution into the cytosol were observed. A mitochondrial site of action for ouabain was further corroborated by tight co-localisation of fluorescent ouabain with mitochondria. Finally, in ouabain-treated cells the histamine-elicited elevation of cytosolic Ca(2+) concentration ([Ca(2+)]c) suggests an additional effect on the endoplasmic reticulum (ER) leading to Ca(2+) store depletion. We conclude that fluorescent ouabain is taken up and tightly co-localises with mitochondria of HeLa cells. This indicates that apoptosis may be triggered by a direct action of ouabain on mitochondria.

Pharmacodynamic genetic variants related to antipsychotic adverse reactions in healthy volunteers

Aim: Clinical trials with healthy volunteers are a useful model for evaluating safety and tolerability, without the interference of concomitant diseases and drugs. The present study aims to improve our understanding of antipsychotic-related adverse reactions (ARs) and their possible association with common genetic variants of pharmacodynamic proteins such as neurotransmitter receptors/transporters. Materials & methods: A total of eight polymorphisms located in seven pharmacodynamic-related genes (SCL6A4, MDR1, 5HT2A, DRD2, DRD3, COMT and GRIN2B) were genotyped in a cohort of 211 healthy volunteers who received a single dose of risperidone (1 mg), olanzapine (5 mg) or quetiapine (25 mg). Results: Interestingly, a significant association was found between the incidence of neurological ARs and specific polymorphisms in key genes (DRD2 and SCL6A4). Conclusion: Genetic variants in pharmacodynamic genes could represent valuable markers of AR risk and antipsychotic safety.

Original submitted 7 February 2013; Revision submitted 3 June 2013

Polymorphisms influencing olanzapine metabolism and adverse effects in healthy subjects

OBJECTIVE

The pharmacokinetics of olanzapine and response to treatment could be affected by polymorphisms in genes coding for drug-metabolizing enzymes, transporters, or receptors. The aim of this study was to identify genetic markers predictive of pharmacokinetics, pharmacodynamics, and adverse effects of olanzapine.

METHODS

Sixty-three healthy volunteers receiving a single 5-mg oral dose of olanzapine were genotyped for 39 genetic variants that could be related to the response to olanzapine. All genetic variants were analyzed by PharmaChip, but DRD2 Taq1A polymorphism was determined by real-time polymerase chain reaction. Olanzapine was measured using high-performance liquid chromatography combined with tandem mass spectrometry. The relationship of gender and polymorphisms with olanzapine pharmacokinetics, the change in prolactin levels, and the incidence of adverse effects were evaluated by multiple regression analysis.

RESULTS

The pharmacokinetics of olanzapine was influenced by polymorphisms in CYP3A5, GSTM3, and GRIN2B. Prolactin levels were affected by gender and polymorphisms in DRD2 and 5-HTR2A. Polymorphisms in CYP2C9, TPMT, UGT1A1, MDR1, and 5-HTR2A were related to some adverse effects of olanzapine.

CONCLUSIONS

Several polymorphisms can explain differences in the pharmacokinetics, pharmacodynamics, and safety of olanzapine in healthy subjects. Whether these genetic factors influence the risk of therapeutic failure or tolerability in patients remains to be established.

Validation of a genotyping method for analysis of TPMT polymorphisms

BACKGROUND

Thiopurine methyltransferase (TPMT) catalyzes the methylation of thiopurine drugs such as azathioprine and 6-mercaptopurine. Several mutations in the TPMT gene correlate with low enzyme activity and adverse effects such as myelotoxicity. Hence, genotyping TPMT makes it possible to identify patients at high risk for drug toxicity.

OBJECTIVE

The aim of this study was to validate a TPMT genotyping method by comparing it with a conventional polymerase chain reaction (PCR) approach.

METHODS

LightSNiP is a real-time PCR method for the detection of TPMT*2, *3B, and *3C without a sequencing step. We evaluated the frequencies of 3 TPMT alleles in 111 white adult patients by comparing genotyping by LightSNiP with conventional PCR (sequencing).

RESULTS

No differences were observed between conventional genotyping with sequencing and LightSNiP for *2, *3B, and *3C, suggesting the validity of this method.

CONCLUSIONS

Compared with the conventional PCR sequencing method, the data suggest that LightSNiP correctly detected the TPMT *2, *3B, and *3C in this select population.

Influence of CYP2C8 and CYP2C9 polymorphisms on pharmacokinetic and pharmacodynamic parameters of racemic and enantiomeric forms of ibuprofen in healthy volunteers

OBJECTIVES

(i) To define the incidence of alleles CYP2C8*1 to *5 in a Spanish population; (ii) to test the impact of such alleles, and those of CYP2C9, on the metabolism of racemic ibuprofen, R-ibuprofen and S-ibuprofen; and (iii) to discern whether those metabolic alterations have safety implications.

METHODS

Data from three phase I clinical trials with 69 healthy volunteers taken ibuprofen were analyzed. Genotyping were performed by PCR. Pharmacokinetic parameters were determined in studies 1 and 2 by non-compartmental analysis. Levels of COX-1, COX-2, eNOS and iNOS were determined by Western Blots in gastric biopsies of study 3.

RESULTS

Allelic frequencies were 0.80, 0.02, 0.11, 0.07 and 0 for CYP2C8*1, *2, *3, *4 and *5. CYP2C9*3 allele had a decreased racemic ibuprofen metabolism, leading to a 30% augmentation of AUC(0-infinity) and a 30% reduction of clearance compared to CYP2C9*1 (p < 0.05). CYP2C8*3 had a 20% augmentation of clearance compared to CYP2C8*1 (p < 0.05) of R-ibuprofen. CYP2C9*3 had a 45% reduction of clearance, as well as a 87% and 47% augmentation of AUC(0-infinity) and t(1/2) with respect to CYP2C9*1 of S-ibuprofen and a 30% reduction of clearance of R-ibuprofen. A decreased iNOS expression was found in CYP2C8*3 compared to wild type (p < 0.05). Adverse events in CYP2C8*3 (20%) and *4 (20%) were fewer than in CYP2C8*1 (77%).

CONCLUSIONS

This study suggest an impaired metabolism of racemic, S-ibuprofen and R-ibuprofen in CYP2C9*3; an increased R-ibuprofen metabolism in CYP2C8*3; and fewer adverse events in CYP2C8*3 volunteers; that correlates with a decreased expression of iNOS.

Lithium and venlafaxine interaction: a case of serotonin syndrome

Serotonin syndrome, which occurs as a result of enhanced serotonin concentration in the central nervous system, is a well-known adverse effect of serotonin-active medications. The concomitant use of antidepressant drugs associated with lithium as a co-adjuvant seems to increase the risk of this adverse reaction. We report a case of the serotonin syndrome during treatment with lithium and venlafaxine, an antidepressant with a dual selective re-uptake inhibition mechanism, and review the literature for similar cases. A 71-year-old woman developed serotonin syndrome while receiving treatment with moderate doses of lithium and venlafaxine for refractory depression. She had been taking higher doses of venlafaxine during the previous months with no significant secondary effects. Use of the Naranjo adverse drug reaction probability algorithm indicated a probable relationship between serotonin syndrome and treatment with lithium and venlafaxine.

An eutomer/distomer ratio near unity does not justify non-enantiospecific assay methods in bioequivalence studies

The aim of the present investigation was to compare the pharmacokinetics of two tablet formulations of 600 mg of racemic ibuprofen obtained using enantiospecific and non-enantiospecific assays, in order to explore if chiral assays should be employed in bioequivalence studies of chiral active substances. The stereoselective assay showed that, for both formulations, there was an initial phase where (R)-ibuprofen was the predominant enantiomer followed by a final phase where (S)-ibuprofen was the predominant one. Results from both analytical methods proved that the two formulations were bioequivalent. However, the chiral bioanalytical method detected a larger difference in the eutomer than that showed by the nonchiral bioanalytical method. In conclusion, although the exposure ratios of enantiomers are near unity, the measurement of unresolved ibuprofen alone is not an adequate measure of bioequivalence since it may mask the actual difference in the eutomer exposure among formulations.

Albumin prevents mitochondrial depolarization and apoptosis elicited by endoplasmic reticulum calcium depletion of neuroblastoma cells

Serum albumin protects against cell death elicited by various cytotoxic agents; however, conflicting views on the protective mechanism still remain. Hence, we have studied the ability of serum albumin to prevent apoptosis of human neuroblastoma SH-SY 5 Y cells elicited by four compounds known to release Ca(2+) from the endoplasmic reticulum, i.e. dotarizine, flunarizine, thapsigargin and cyclopiazonic acid. Spontaneous basal apoptosis, after 24 h incubation in Dulbecco's Modified Eagle Medium (DMEM) containing 10% serum, was 5%. Dotarizine (30--50 microM) enhanced basal apoptosis to 18--43%, flunarizine (30--50 microM) to 15%, thapsigargin (1--10 microM) to 21--35%, and cyclopiazonic acid (100 microM) to 10%. Serum deprivation augmented basal apoptosis to 20%. Under serum-free medium, 30 microM dotarizine or flunarizine drastically enhanced apoptosis to 63% and 68%, respectively; the increase was milder with 1 microM thapsigargin (37%) and 30 microM cyclopiazonic acid (27%). In serum-free medium, albumin (29 or 49 mg/ml) fully prevented the apoptotic effects of dotarizine, flunarizine and cyclopiazonic acid. The four compounds increased the cytosolic Ca(2+) concentration ([Ca(2+)](c)) in fluo-4 loaded cells; such increase developed slowly to reach a plateau after several minutes, followed by a slow decline. Albumin did not modify the kinetic parameters of such increase. In the absence of serum, dotarizine, flunarizine, thapsigargin, and cyclopiazonic acid caused mitochondrial depolarization in tetramethylrhodamine ethyl ester (TMRE)-loaded cells; depolarization was inhibited by cytoprotective concentrations of albumin. These results suggest that albumin protects cells from entering into apoptosis by preventing mitochondrial depolarization. They also suggest that inhibition of mitochondrial depolarization might become a target to develop new anti-apoptotic compounds with therapeutic neuroprotective potential in stroke, Alzheimer's disease, and other neurodegenerative diseases.

Assessment of sex differences in pharmacokinetics and pharmacodynamics of amlodipine in a bioequivalence study

AIMS

This study was conducted to assess the bioequivalence between two 10-mg amlodipine tablet formulations. As secondary objectives, sex-related differences and tolerability profile were evaluated.

METHODS

Thirty-six healthy volunteers (18 males and 18 females; age 20-32 years, weight 49.5-98.0 kg) were included in a randomised crossover study. Subjects were administered a single 10-mg oral dose of each formulation separated by a 14-day washout period. Plasma amlodipine levels were determined by a high performance liquid chromatographic method with tandem mass spectrometry detection.

RESULTS

All subjects completed the study and 90% confidence intervals for relevant pharmacokinetic parameters were within the ranges defined by European and US Regulatory Authorities: the geometric mean and the 90% confidence interval test/reference ratios calculated from log-transformed values were 104.54 (101.46-107.72%) for AUC(0-infinity) and 100.32 (97.41-103.33%) for Cmax. There were no serious or severe adverse events. The tolerability profile appeared to be comparable for the two products. On average, bioavailability of amlodipine was slightly higher in females than in males, but these differences could be explained by the lower body weight of women. There were no sex-related differences in drug clearance. Bioequivalence was also demonstrated within each gender group. Amlodipine treatment produced a slight decrease of systolic blood pressure and an increased in heart rate, which were more pronounced in women. The incidence of adverse events was similar in men and women.

CONCLUSIONS

The two formulations were considered bioequivalent. Although there were no relevant gender-related differences in the pharmacokinetics of amlodipine, women reached higher amlodipine concentrations most likely because of their lower body weight, and therefore, the reported pharmacodynamic effects were higher within this gender group.

Gender differences in angiotensin-converting enzyme (ACE) activity and inhibition by enalaprilat in healthy volunteers

This bioequivalence study was supported by Laboratorios Vita S.A (Barcelona). To study the existence of differences between sexes in the pharmacokinetic and pharmacodynamic of enalapril. A bioequivalence phase 1 clinical trial to compare two formulations of enalapril was carried out in twenty-four healthy volunteers (12 men and 12 women). Enalaprilat concentrations, plasma activity of ACE, and systolic and diastolic arterial pressure were determined. Basal activity of ACE and the maximum ACE inhibition were significantly smaller in women. No significant differences in the drug concentration required to produce 50% of Emax were observed. Women had lower systolic arterial pressures and ACE activities than men at any time, even when the maximum inhibition of the ACE activity was attained. Women at the follicular phase had a minimum activity of ACE significantly inferior than men. Healthy women had lower systolic arterial pressures and ACE activities than men.

Effect of ibuprofen on cyclooxygenase and nitric oxide synthase of gastric mucosa: correlation with endoscopic lesions and adverse reactions

The aim of this study was to evaluate the effect of ibuprofen on gastric mucosa and enzymes involved in gastroprotection in healthy volunteers. Twenty-four Helicobacter pylori-negative subjects were randomized to treatment with ibuprofen or ibuprofen-arginate (each 600 mg/6 hr during 3 days). Endoscopies were performed 1 week before and after treatment. Biopsies were taken from the gastric antrum and corpus for determination of prostaglandin E2 (PGE2) by ELISA and cyclooxygenase (COX-1 and COX-2) and nitric oxide synthase (eNOS and iNOS) by western blot. All subjects had at least one gastric lesion except for two individuals taking ibuprofen-arginate. Ibuprofen-arginate caused a lower rate of clinical adverse reactions than ibuprofen. Subjects with gastric lesions or adverse reactions had lower PGE2 levels. COX-1, COX-2, eNOS, and iNOS were detectable in all subjects. The constitutive enzymes (COX-1 and eNOS) did not change after treatment. COX-2 was higher in corpus than antrum and it increased after ibuprofen treatment. iNOS tended to increase mildly in the corpus in subjects with adverse reactions or endoscopic lesions. There were no significant differences between ibuprofen and ibuprofen-arginate in PGE2, or enzymes.

The comparative hemodynamic effects of intravenous IQB-9302 and bupivacaine in anesthetized rats

BACKGROUND

The new local anesthetic IQB-9302 is an amide derivative bearing a cyclopropyl group, with remarkable long duration of action and relative low toxicity. In trying to characterize further its safety profile, the current study compared the hemodynamic effects of different concentrations of bupivacaine and IQB-9302 with saline.

METHODS

Two groups of eight anesthetized Sprague-Dawley rats were given 0.1, 0.3, 1, 3, and 10 mg/kg of intravenous (i.v.) IQB-9302 or bupivacaine at 20-min intervals; control animals received saline only. Arterial blood pressure and heart rate were monitored during the following 20 min.

RESULTS

Both bupivacaine and IQB-9302 reduced heart rate: for bupivacaine, -73.8 beats per min (bpm) (SD: 103.8) and -132.5 bpm (SD: 140.7) at 1 and 3 mg/kg, respectively; for IQB-9302, the reduction amounted to -40.8 bpm (SD: 14.2) and -113.5 bpm (SD: 94.2) at 1 and 3 mg/kg, respectively (baseline range, 318.7-438.2 bpm). The two drugs also produced a comparable increase in the mean arterial blood pressure; bupivacaine increased it by 8.7 mmHg (SD: 6.6) and 12.6 mmHg (SD: 15.4) at 1 and 3 mg/kg, respectively, and IQB-9302, 18.7 mmHg (SD: 21.1) and 20.7 mmHg (SD: 20.5) at 1 and 3 mg/kg, respectively (baseline range, 47.4-134.1 mmHg). All rats treated with 10 mg/kg of either drug died after a drop in heart rate and mean arterial blood pressure.

CONCLUSION

IQB-9302 had hemodynamic effects similar to those of bupivacaine in anesthetized rats. The clinical relevance of these effects warrants further investigation.

[Meta-analysis of clarithromycin compared to other antibiotics for the treatment of lower respiratory tract infections]

Clarithromycin is a macrolide antibiotic commonly used for the treatment of respiratory infections. The aim of this study was to assess its effectiveness for the treatment of lower respiratory tract infections. A number of meta-analyses of clinical trials comparing clarithromycin to the antibiotics most frequently used in the treatment of lower respiratory tract infections, such as cephalosporins, amoxicillin-clavulanic acid, erythromycin and azithromycin, have been performed. Clarithromycin's effectiveness for the treatment of lower respiratory tract infections was better than that for cephalosporins (OR = 1.43; 95% CI = 1.09-1.86) and, although not to the same extent, that for amoxicillin-clavulanic acid (OR = 1.58; 95% CI = 0.92-2.70); however, the efficacy was only similar to that shown for azithromycin (OR = 0.57; 95% CI = 0.19-1.68). The fourth meta-analysis compared the effectiveness of clarithromycin to that of erythromycin for the treatment of pneumonia and showed a superior odds ratio in favor of clarithromycin (OR = 1.46; 95% CI = 0.97-2.2). Meta-analyses comparing clarithromycin's safety to that of the same drugs in the same conditions used in the assessment of effectiveness showed a similar incidence of adverse events compared to amoxicillin-clavulanic acid, and azithromycin, a slightly lower incidence compared to erythromycin, and a slightly higher incidence compared to cephalosporins. In conclusion, these meta-analyses show that clarithromycin is an effective and safe antibiotic for the treatment of lower respiratory tract infections. Furthermore, a new once-daily dose formulation with a positive impact on therapeutic compliance is currently available, making clarithromycin a first-line treatment for lower respiratory tract infections.

[Meta-analysis of clarithromycin compared with other antimicrobial drugs in the treatment of upper respiratory tract infections]

The goal of this meta-analysis was to evaluate the effectiveness of clarithromycin versus most commonly used treatments for upper respiratory infections. We performed a systematic review of comparative clinical trials found in the literature. Regarding effectiveness, no significant differences were found in comparisons between clarithromycin and amoxicillin-clavulanic acid for upper respiratory infections, nor for cephalosporins, amoxicillin or amoxicillin-clavulanic acid for otitis media, nor oral penicillin for classic streptococcal tonsillitis. Clarithromycin was more effective than betalactam antibiotics for sinusitis (OR: 1.27, 95% CI: 1.01-1.61 in intent-to-treat analysis). The effectiveness of clarithromycin was better than that for azithromycin, but only reached statistical significance in the per-protocol analysis. The global analysis including all 33 clinical trials showed a small benefit for clarithromycin reaching statistical significance in the fixed-effects model (OR: 1.12, 95% CI: 1.01-1.25). Regarding safety, the incidence of adverse events was significantly lower for clarithromycin compared to amoxicillin and amoxicillin-clavulanic acid. No differences were found when comparing adverse events due to cephalosporins, azithromycin and betalactam antibiotics, but the incidence of adverse events for clarithromycin was higher compared to that of oral penicillin for streptococcal tonsillitis treatment. Overall, all the compared drugs were well tolerated; discontinuations due to adverse events were very low: 2.2% for clarithromycin treatment and 2.5% for the other antibiotics. It was concluded that clarithromycin is an effective and safe treatment for upper respiratory infection, and its new formulation in a single daily dose may improve therapeutic compliance.

[Regulation of bronchial tone in chronic obstructive pulmonary disease (COPD): role of muscarinic receptors]

Anticholinergic agents have proved to be of particular value in the treatment of COPD, as vagal cholinergic tone appears to be the only reversible component of airway narrowing, opposite to what happens in asthma. Anticholinergics block muscarinic receptors on airway smooth muscle an submucosal gland cells. Three subtypes of muscarinic receptors have been demonstrated in human airways. M1 receptors in parasympathetic ganglia facilitate cholinergic neurotransmission. M3 receptors on airway smooth muscle cells and glands mediate bronchoconstriction and mucus secretion. M2 receptors at cholinergic nerve endings inhibit the release of acetylcholine and therefore act as feedback inhibitory receptors (autoreceptors). Ipratropium bromide is a non-selective muscarinic antagonist and therefore blocks M1, M2 and M3 receptors. Tiotropium is a novel, potent, and long-lasting muscarinic antagonist that has a kinetic selectivity for M1 and M3 receptors because it dissociated very quickly from M2 receptors. Once-daily inhaled tiotropium is a safe and effective bronchodilator useful as a first-line maintenance therapy in COPD.

Pharmacokinetics and pharmacodynamics of a single bolus of propofol 2% in healthy volunteers

This study was undertaken to assess the bioequivalence between a new formulation of propofol 2% and the commercially available product Diprivan. Secondary objectives were to compare the times to onset of and emergence from hypnosis, the hemodynamic effects, and the safety profiles. Twelve healthy male volunteers were included in a randomized crossover study. Subjects were administered a 2-mg/kg single bolus injection of each formulation separated by a 7- to 10-day washout period. Plasma propofol was determined by reversed-phase liquid chromatography with fluorescence detection. Eleven subjects completed the study, and both formulations were considered bioequivalent. There were no serious or severe adverse events. The concentration-time profiles of all the subjects could adequately be described using a three-compartment model. The mean times to cessation of counting out loud (17 vs. 18 s) and to eye opening (245 vs. 244 s) were not statistically different between treatment groups. Moreover, they seem to show some degree of pharmacodynamic bioequivalence, although a higher number of subjects are necessary to unequivocally demonstrate it.

Survey of oral hydrocortisone utilization in Madrid (Spain)

A progressive 69% increase in sales of hydrocortisone tablets was observed in Spain from 1988 to 1995. But there were no data suggesting an increase in the number of adrenal insufficiency cases. We aimed to assess the hydrocortisone prescription habits of physicians in 1996 in Madrid (Spain). An anonymous mail questionnaire was sent to 6130 randomly selected physicians (3345 generalists and 2785 specialists) of Madrid. Five hundred and forty-six questionnaires (8.8%) were returned. Three hundred and eighteen physicians (58.2%) sometimes prescribed oral hydrocortisone. 70.8% of these physicians prescribed hydrocortisone for chronic adrenal insufficiency, 17.3% for acute adrenal insufficiency, 7.9% for congenital adrenal hyperplasia, and 30.2% for inflammatory diseases (asthma, allergic diseases, urticaria, rheumatic diseases, ulcerative colitis). Prescription for inflammatory diseases was more frequent in male physicians, physicians older than 40 years, and general practitioners. We can conclude that the main indication for hydrocortisone prescription was chronic adrenal insufficiency but there was a significant number of physicians that used the drug in inflammatory diseases. As a drastic increase in prevalence of adrenal insufficiency seems unlikely, the augmentation in sales of hydrocortisone could be explained by its prescription for other pathologies.

Ulnar nerve block induced by the new local anesthetic IQB-9302 in healthy volunteers: a comparison with bupivacaine

We evaluated the duration of sensory anesthesia after blockade of the ulnar nerve of IQB-9302, a new local amide anesthetic, compared with bupivacaine. A double-blinded, randomized, cross-over study in 12 healthy volunteers aged 18 to 35 yr was performed. Three milliliters of 0.25% IQB-9302 was administered in one wrist and bupivacaine in the other. A week later, the blocks were repeated with a concentration of 0.5%. These concentrations were chosen because they seemed to be equipotent in previous studies. The duration of sensory anesthesia was the main variable measured; secondary outcomes were motor block, time to onset, and time to recovery from block. The duration of sensory block was similar for IQB-9302 and bupivacaine at a concentration of 0.25%; median and range: 409 min (0-800 min) for IQB-9302 and 258 min (0-665 min) for bupivacaine (95% confidence interval for the difference from -47 to 545, P = 0.82, Wilcoxon's test). The results with 0.5% were: 525 min (440-735 min) and 690 min (365-1098 min), respectively (P = 0.026). There were no significant differences in the other variables measured. No important adverse reactions were seen. We conclude that IQB-9302 is an effective new local anesthetic for blockade of ulnar nerve at the concentrations tested.

IMPLICATIONS

IQB-9302 is a new local anesthetic that has shown a long duration of action and low cardiovascular toxicity in preclinical studies. We report the results of a phase I clinical trial to compare this new drug with bupivacaine for ulnar nerve block.

Altered regulation of calcium channels and exocytosis in single human pheochromocytoma cells

We established primary cultures of human pheochromocytoma chromaffin cells. We then tried to find what mechanism of their secretory apparatus could be altered to produce the massive release of catecholamines into the circulation and the subsequent hypertensive crisis observed in patients suffering this type of tumor. Their whole-cell Ca2+ channel currents could be pharmacologically separated into components similar to those found in normal human adrenal chromaffin cells: 20% L-type, 30% N-type, and 50% P/Q-type Ca2+ channels. However, modulation of the channels by exogenous or endogenous ATP and opioids, via a G-protein membrane-delimited pathway, was deeply altered; some cells having no modulation or very little modulation alternated with others having normal modulation. This may be the cause of the uncontrolled secretory response, measured amperometrically at the single-cell level. Some cells secreted for long time periods and were insensitive to nifedipine (L-type channel blocker) or to omega-conotoxin MVIIC (N/P/Q-type channel blocker), while others were highly sensitive to nifedipine and partially sensitive to omega-conotoxin MVIIC. Alteration of the autocrine/paracrine modulation of Ca2+ channels may lead to indiscriminate Ca2+ entry and exacerbate catecholamine release responses in human pheochromocytoma cells.

[The current state of citicholine in cerebral ischemia]

INTRODUCTION

Citicoline has a neuroprotector effect since it reduces the lesions of nerve membranes, by increase in the synthesis of phospholipids, and reduces the levels of free fatty acids. In this study we review the existing data on the efficacy of citicoline in the treatment of acute ischemic cerebrovascular disease and its sequelae, both in animals and in clinical trials involving patients.

DEVELOPMENT

In various animal models citicoline reduces the volume of cerebral infarction and neurological sequelae and also potentiates the effects of other neuroprotector drugs. On analysis of the literature, we found six randomised clinical trials, double-blind and placebo-controlled in which the effect of citicoline was evaluated in patients who had acute ischemic cerebrovascular accidents. In all of these it was found that citicoline reduced the neurological sequelae. The finding of a broad therapeutic window (24-48 hours) gives this an advantage over the fibrinolytic agents, which have to be given within the first three to six hours. In further controlled trials carried out in patients with sequelae of cerebrovascular disease different degrees of neurological improvement were found, although studies of greater duration are required to see improvement in a longer term.

CONCLUSIONS

With the data available, we may affirm that citicoline is a safe, effective drug, although clinical trials are still underway in larger populations of patients. In these trials not only the neurological state but also the area of infarction are assessed to confirm their efficacy.

L-Type calcium channels in enterochromaffin cells from guinea pig and human duodenal crypts: an in situ study

BACKGROUND & AIMS

This study has investigated stimulus-secretion coupling of enterochromaffin cells by studying the cellular location and function of voltage-gated Ca(2+) channels within small intestinal crypts.

METHODS

Digital fluorescence imaging and electrochemical detection were used to measure intracellular Ca(2+) responses and serotonin (5-hydroxytryptamine [5-HT]) secretion in intact crypts isolated from guinea pig and human duodenum.

RESULTS

In fluo-3-loaded crypts, electrical depolarization with high K(+) solution increased cytosolic free [Ca(2+)] only in single cells subsequently identified by immunocytochemistry as enterochromaffin cells. In guinea pig enterochromaffin cells, the L-type Ca(2+) channel agonist FPL 64176 (3 micromol/L) did not change resting intracellular [Ca(2+)] but potentiated the depolarization-evoked increase in [Ca(2+)] (298 +/- 72 nmol/L) by 19 +/- 3-fold. In the majority of human enterochromaffin cells, FPL 64176 alone increased resting [Ca(2+)] by 423 +/- 171 nmol/L. Secretion studies in guinea pig crypts showed that high K(+) and FPL 64176 caused a 12-fold increase in 5-HT release. Noradrenaline caused increases in both enterochromaffin cell [Ca(2+)] and 5-HT release.

CONCLUSIONS

Using this approach, we have found that in duodenal crypts, enterochromaffin cells, but not other epithelial cells, contain L-type voltage-gated Ca(2+) channels involved in regulating 5-HT secretion. These data have implications for the pharmacological control of intestinal disorders involving enterochromaffin cell dysfunction.

A rapid method for the evaluation of compounds with mitochondria-protective properties

Mitochondrial dysfunction has been implicated in a number of neurodegenerative diseases, such as ischemia and Parkinson's disease. We present here a method that allows the rapid quantification of interventions, aimed at inhibiting the effect of mitochondrial membrane potential uncouplers, based on the ratioing properties of the fluorescent probe 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide (JC-1), by using currently available 96-well fluorescent plate readers. A method is presented for evaluation of cross-talk between the two excitation/emission channels. Further characterization of the probe shows that the effect of plasma membrane potential changes on JC-1 fluorescence ratio are negligible, but that the signal is very sensitive to pH. One of the most exciting applications is the possibility to perform end-point measurements, thanks to the ratioing properties of the probe. The system is tested in different culture types with different mitochondrial uncouplers. As an example of a quantitative evaluation, we show that flunarizine is able to inhibit, dose-dependently, FCCP mediated JC-1 signal increase. The procedure is simple and allows for the fast screening of mitochondria-protective compounds.

Novel antimigraineur dotarizine releases Ca2+ from caffeine-sensitive Ca2+ stores of chromaffin cells

1. The novel antimigraineur, dotarizine (30 microM), increased cytosolic Ca2+ concentration, [Ca2+]c, in fura-2-loaded bovine adrenal chromaffin cells. This increase was transient, reached a peak in about 2 - 5 min (0.53+/-0.07 microM; n=19) and then declined to basal levels over a further 5 min period. 2. This transient rise of [Ca2+]c was mimicked by 1 microM thapsigargin and by 30 microM cyclopiazonic acid (CPA), but not by 30 microM flunarizine. Both thapsigargin and CPA occluded the effects of dotarizine and vice versa. 3. All three compounds suppressed the transient [Ca2+]c rises induced by caffeine (10 mM, 10 s); blockade induced by thapsigargin was irreversible and that induced by CPA and dotarizine was reversible. 4. Of the three compounds, only dotarizine blocked reversibly the [Ca2+]c spikes induced by short pulses of high K+ (70 mM, 5 s), suggesting that dotarizine blocks voltage-dependent Ca2+ channels but CPA and thapsigargin do not. 5. Dotarizine caused a gradual and reversible depletion of endoplasmic reticulum (ER) Ca2+ in chromaffin cells transfected with ER-targeted aequorin. CPA had a similar effect. 6. These data show that dotarizine shares with thapsigargin and CPA the ability to deplete Ca2+ in the ER; this novel action of dotarizine could be relevant to its prophylactic effects in migraine. Unlike thapsigargin and CPA, however, dotarizine additionally and reversibly blocks Ca2+ entry through voltage-dependent Ca2+ channels.

Effects of dotarizine and flunarizine on chromaffin cell viability and cytosolic Ca2+

Dotarizine (a novel piperazine derivative with antimigraine properties) and flunarizine (a Ca2+ channel antagonist) were compared concerning: first, their ability to cause chromaffin cell damage in vitro; second, the possible correlation of their octanol/water partition coefficients and those of another 28 compounds (i.e., Ca2+ channel antagonists, blockers of histamine H1 receptors, antimycotics, beta-adrenoceptor antagonists, neuroleptics), with their ability to cause cell damage; third, their capacity to protect the cells against the damaging effects of veratridine; and fourth, their capabilities to enhance the basal cytosolic Ca2+ concentration in fura-2-loaded single chromaffin cells, or to modify the pattern of [Ca2+]i oscillations elicited by veratridine. After 24-h exposure to 1-30 microM dotarizine, the viability of bovine adrenal chromaffin cells (measured under phase contrast or as lactate dehydrogenase, released into the medium) was similar to that of control, untreated cells; at 100 microM, 80% lactate dehydrogenase release was produced. At 1-3 microM flunarizine caused no cell damage; however 10 microM caused 20% lactate dehydrogenase release and 30 and 100 microM over 90% lactate dehydrogenase release. The time course of cell damage was considerably faster for flunarizine, in comparison to dotarizine. Out of 30 molecules tested (at 10 microM), having different octanol/water partition coefficients (log P), dotarizine was among the molecules causing no cell damage; flunarizine caused 20% cell loss, lidoflazine and verapamil over 50% cell loss, and penfluridol, draflazine, astemizole or nifedipine over 80% cell loss. No correlation was found between log P and cytotoxicity. Both dotarizine (10-30 microM) and flunarizine (3-10 microM) provided protection against veratridine-induced cell death; however, at 30 microM dotarizine afforded a pronounced protection while flunarizine enhanced the cytotoxic effects of veratridine. Dotarizine (30 microM) (but not flunarizine) caused a prompt transient elevation of the basal [Ca2+]i. Both compounds abolished the K+-induced increases of [Ca2+]i as well as the oscillations of [Ca2+]i induced by veratridine. The blocking effects of dotarizine were readily reversed after washout, while those of flunarizine were long-lasting. These differences might be relevant to the clinical use of dotarizine as an antimigraine drug.