The Efficacy of Nitrates for Bone Health: A Systematic Review and Meta-Analysis of Observational and Randomized Controlled Studies

BACKGROUND

Although some studies have found that nitrates were beneficial for bone health, the findings are inconsistent. To assess the efficacy of nitrates for bone health, we conducted a meta-analysis.

METHODS

PubMed, EMBASE databases, Cochrane Library for relevant articles published before December 2021 were searched. All observational and randomized controlled studies that reporting bone mineral density (BMD), fractures with nitrates use were included. A meta-analysis was performed to calculate risk ratios (RRs) for fractures, change differences for bone mineral density.

RESULTS

Four cohort studies and two case-control studies examining the association between nitrates use and fractures were identified. The nitrates use was not associated with any fracture risk (RR = 0.97; 95% CI, 0.94-1.01; I² = 31.5%) and hip fracture (RR = 0.88; 95% CI, 0.76-1.02; I² = 74.5%). Subgroup analyses revealed no differences in fracture risk, whereas two cohort studies revealed a reduced risk of hip fracture (RR = 0.71, 95% CI, 0.58-0.86, I² = 0.0%). There were no statistically significant differences in BMD percent changes at lumbar spine (WMD = -0.07, 95% CI,-0.78-0.65; I² = 0.0%), total hip (WMD = -0.42, 95% CI,-0.88-0.04; I² = 0.0%), femoral neck (WMD = -0.38, 95% CI,-1.02-0.25; I² = 0.0%), or total body (WMD = -0.17, 95% CI,-0.51-0.17; I² = 0.0%) in two randomized controlled trials (RCTs) compared with a placebo. Another two RCTs compared nitrates with alendronate. Nitrates were comparable to alendronate in increasing bone mineral density at lumbar spine (WMD = 0.00, 95% CI,-0.01-0.02; I² = 0.0%). Besides, the most common adverse effect was headache, contributing to low adherence to therapy.

CONCLUSION

Our meta-analysis showed no association between nitrates use and fractures in observational studies. The results of RCTs on the usage of nitrates and their effects on BMD were inconsistent. High-quality, long-term studies are needed to clarify the efficacy of nitrates for bone health.

In silico prediction of bioequivalence of Isosorbide Mononitrate tablets with different dissolution profiles using PBPK modeling and simulation

AIM

The waiver of bioequivalence (BE) studies is well accepted for Biopharmaceutics Classification System (BCS) class I drugs in form of immediate-release solid oral products. This study aimed to assess whether the rapid dissolution profiles (≥85% in 30 min) was crucial to guarantee bioequivalence of isosorbide mononitrate (ISMN) and then established a clinically relevant dissolution specification (CRDS) for screening BE or non-BE batches.

METHOD

A physiologically based pharmacokinetic (PBPK) model was constructed by integrating clinical and non-clinical data by B²O simulator. The model was verified by an actual clinical study (NMPA registration number: CTR20191360) with 28 healthy Chinese subjects. Then a virtual BE study was simulated to evaluate the bioequivalence of 7 virtual batches of ISMN tablets with different dissolution profiles, and the CRDS was established by integrating the results.

RESULT

The simulated PK behavior of ISMN was comparable to the observed. Even though the batches with slower dissolution were not equivalent to a rapid dissolution profile (≥85% in 30 min), it was demonstrated these batches would exhibit the similar in vivo performance. Meanwhile, the in vitro dissolution specification time point and the percentage of drug release (75% in 45 min) proved to have clinical relevance.

CONCLUSION

The virtual BE simulation by integrating in vitro dissolution profiles into the PBPK model provided a powerful tool for screening formulations, contributing to gaining time and reducing costs in BE evaluations.

High-dose nitrate therapy recovers the expression of subtypes α1 and β-adrenoceptors and Ang II receptors of the renal cortex in rats with myocardial infarction-induced heart failures

BACKGROUND

Few studies examined the effect of long-acting nitrates on renal function in chronic heart failure (CHF). Thus, we aimed to investigate the effect of long-acting nitrate on the expression of adrenoceptors (AR) and angiotensin II receptor (ATR) subtypes of the renal cortex, in rats with myocardial infarction-induced CHF.

METHODS

Rats were randomly divided into the following groups: control, sham-operated, CHF, low- and high-dose nitrate, positive drug control (olmesartan), and high-dose of long-acting nitrate + olmesartan. Ultrasound echocardiography markers were compared, and the levels of AR subtypes, AT1R, and AT2R were measured using reverse transcription-polymerase chain reaction and western blot analysis. Histopathology of the kidney was determined on hematoxylin and eosin-stained sections.

RESULTS

CHF significantly increased plasma renin activity (PRA) and angiotensin II levels, upregulated AT1R expression and downregulated α1A-, β1-, β2-AR, and AT2R expression compared to the sham control. High-dose nitrate or olmesartan alone, and especially in combination, decreased the levels of PRA and angiotensin II and downregulated the CHF-induced expression of AT1R, α1A-, β1-, and β2-AR, and AT2R. CHF resulted in significant impairment of the renal tissue, including inflammatory cells infiltration to the tubular interstitium and surrounding the renal glomerulus, and tubular necrosis, which was alleviated in all treatment groups to different degrees.

CONCLUSIONS

Long-acting nitrates could reverse CHF-induced changes in AR and ATR subtypes in the kidney, and improve cardiac function to protect renal function. Compared with monotherapy, the combination of nitrates and olmesartan shows more significant benefits in regulating AR and ATR subtypes.

Permeation-enhancing effects and mechanisms of O-acylterpineol on isosorbide dinitrate: mechanistic insights based on ATR-FTIR spectroscopy, molecular modeling, and CLSM images

The present study aimed to evaluate the penetration activity of O-acylterpineol derivatives both in vitro and in vivo, and to investigate the enhancing mechanism of O-acylterpineol derivatives which were synthesized by α-terpineol and fatty acid. The promoting activities on the isosorbide dinitrate patch were tested across full thickness rabbit skin both in vitro and in vivo. In order to elucidate the permeation mechanism, attenuated total reflection Fourier transform infrared spectroscopy, molecular modeling, and confocal laser scanning microscopy were introduced to investigate the regulation of enhancers in the skin permeability and biophysical properties. With in vitro cytotoxicity test and in vivo erythema model, the skin irritation of enhancers was also evaluated. Permeation studies showed 2-(4-methylcyclohex-3-en-l-yl) propan-2-yl tetradecanoate produced the obvious enhancement activity for ISDN both in vitro and in vivo from patches. These results were supported by ATR-FTIR, molecular modeling, and CLSM studies which revealed that O-acylterpineol could decrease the order of the alkyl chains in the skin lipids. Additionally, it was found that TER-C14 produced a relatively low skin irritation, compared with the TER which was assumed to be a safe compound. The present research suggested that some newly designed acylterpineol derivatives are shown to be suitable permeation enhancers for transdermal drug delivery, and the chain length of C14 seem to be safe and more favorable for the penetration of ISDN from DIA patches.

Physical Activity, Quality of Life, and Biomarkers in Atrial Fibrillation and Heart Failure With Preserved Ejection Fraction (from the NEAT-HFpEF Trial)

Although atrial fibrillation/atrial flutter (AF/AFL) and heart failure with preserved ejection fraction (HFpEF) frequently coexist, the influence of AF/AFL on physical activity, N-terminal pro-B-type natriuretic peptide (NT-proBNP), and quality of life in HFpEF is unclear and could have relevance to HFpEF trial design. We evaluated the association between AF/AFL and volitional physical activity, functional performance, NT-proBNP, and quality of life in patients with HFpEF in the Nitrate's Effect on Activity Tolerance (NEAT)-HFpEF trial. Of 99 patients with accelerometer data, 35 (35%) had AF/AFL. There were no differences between AF/AFL versus no AF/AFL in baseline average daily accelerometer units (ADAUs; 9.06 ± 0.54 vs 9.06 ± 0.48, p = 0.75), hours active per day (9.7 ± 2.3 vs 9.2 ± 2.2, p = 0.86), or 6-minute walk distance (6MWD; 307 ± 136m vs 321 ± 110m, p = 0.85). AF/AFL status was associated with higher baseline NT-proBNP (586 [25th to 75th percentile: 291 to 1254] pg/ml vs 154 [25th to 75th percentile: 92 to 288] pg/ml, p <0.001) and Kansas City Cardiomyopathy Questionnaire scores (69 [25th to 75th percentile: 46 to 88] vs 48 [25th to 75th percentile: 37 to 70], p = 0.01). Although treatment responses to isosorbide mononitrate measured by change in ADAUs, hours active per day, or 6MWD did not vary by AF/AFL status (interaction p >0.05 for all), AF/AFL patients had greater reductions in NT-proBNP after isosorbide mononitrate than patients without AF/AFL (interaction p <0.001), possibly due to regression to the mean. In conclusion, baseline measures and treatment-related changes in volitional physical activity (ADAUs) and functional performance (6MWD) did not differ by AF/AFL in NEAT-HFpEF, whereas NT-proBNP did. In HFpEF-where AF/AFL prevalence is high-functional measures may be superior to natriuretic peptides as trial endpoints.

Nitric oxide donors increase the pregnancy rate in patients with unexplained infertility undergoing clomiphene citrate stimulation and intrauterine insemination: a randomized controlled pilot study

This study evaluated the effects of nitric oxide donor's treatment on the pregnancy rate and uterine blood flow in patients with unexplained infertility undergoing clomiphene citrate stimulation and intrauterine insemination. A total of 120 patients were randomly allocated to a control group who received 100 mg clomiphene citrate daily from day 5 to 9 of cycle plus placebo vaginal tablets, and a study group received clomiphene citrate plus isosorbide mononitrate 10 mg vaginal tablets. Vaginal ultrasound was done before treatment and every other day starting from day 12 of cycle to count mature follicles and ovulation was triggered by IM injection of 10 000 IU hCG when one follicle measured 18 ≥ mm followed by intrauterine insemination after 36 h. The endometrial thickness, uterine arteries resistance and pulsation indices, and endometrial vascular flow and vascular flow indices were measured before treatment and at day of hCG injection. Results were analyzed after one cycle treatment using the Mean ± SD, the Student t test and the Fisher Exact test. Significant result was considered at p values <0.05. The study group had significant higher pregnancy rate/cycle, higher endometrial and lower uterine artery blood flow indices (p < 0.05).

Comparison between Flurbiprofen and its Nitric Oxide-Releasing Derivatives HCT-1026 and NCX-2216 on Aβ(1-42)-Induced Brain Inflammation and Neuronal Damage in the Rat

Brain inflammation is an underlying factor in the pathogenesis of Alzheimer's disease (AD) and epidemiological studies indicate that a sustained use of non-steroidal anti-inflammatory drugs (NSAIDs) has a protective effect on the disease. We investigated, in vivo, whether differences exist in the antiinflammatory and neuroprotective actions of flurbiprofen and its two nitric oxide-donor derivatives, HCT-1026 and NCX-2216, and the ability of these two derivatives to release nitric oxide in the brain. In adult rats injected into the nucleus basalis with preaggregated Aβ(1-42) we investigated by immunohistochemical methods glia reaction, the induction of inducible nitric oxide synthase (iNOS), the activation of p38 mitogen-activated protein kinase (p38MAPK) pathway and the number of choline acetyltransferase (ChAT)-positive neurons and, in naïve rats we investigated, by microdialysis, cortical extracellular levels of nitrite. Injection of Aβ(1-42) induced iNOS at the injection site, activated p38MAPK 7 days after injection and brought about an intense microglia and astrocyte reaction along with a marked reduction in the number of ChAT-positive neurones, persisting up to at least up to 21 days. Flurbiprofen, HCT-1026 and NCX-2216 (15 mg/kg) significantly attenuated the Aβ(1-42)-induced glia reaction, iNOS induction and p38MAPK activation 7 days after treatment and astrocytes reaction 21 days after treatment. On an equimolar basis, HCT-1026 resulted the most active agent in reducing the Aβ(1-42)-induced microglia reaction. The cholinergic cell loss was also significantly reduced by 21 days of HCT-1026 treatment. No differences in the body weight were found between the animals treated for 21 days with 15 mg/kg of either HCT-1026 or NCX-2216 and the controls. An oral administration of HCT-1026 (15 mg/kg) or NCX-2216 (100 mg/kg) to naiïve rats was followed by significant and long long -lasting increases in cortical nitrite levels. These findings indicate that the addition of a nitric oxide donor potentiates the anti-inflammatory activity of flurbiprofen in a model of brain inflammation.

Isosorbide Mononitrate in Heart Failure with Preserved Ejection Fraction

BACKGROUND

Nitrates are commonly prescribed to enhance activity tolerance in patients with heart failure and a preserved ejection fraction. We compared the effect of isosorbide mononitrate or placebo on daily activity in such patients.

METHODS

In this multicenter, double-blind, crossover study, 110 patients with heart failure and a preserved ejection fraction were randomly assigned to a 6-week dose-escalation regimen of isosorbide mononitrate (from 30 mg to 60 mg to 120 mg once daily) or placebo, with subsequent crossover to the other group for 6 weeks. The primary end point was the daily activity level, quantified as the average daily accelerometer units during the 120-mg phase, as assessed by patient-worn accelerometers. Secondary end points included hours of activity per day during the 120-mg phase, daily accelerometer units during all three dose regimens, quality-of-life scores, 6-minute walk distance, and levels of N-terminal pro-brain natriuretic peptide (NT-proBNP).

RESULTS

In the group receiving the 120-mg dose of isosorbide mononitrate, as compared with the placebo group, there was a nonsignificant trend toward lower daily activity (-381 accelerometer units; 95% confidence interval [CI], -780 to 17; P=0.06) and a significant decrease in hours of activity per day (-0.30 hours; 95% CI, -0.55 to -0.05; P=0.02). During all dose regimens, activity in the isosorbide mononitrate group was lower than that in the placebo group (-439 accelerometer units; 95% CI, -792 to -86; P=0.02). Activity levels decreased progressively and significantly with increased doses of isosorbide mononitrate (but not placebo). There were no significant between-group differences in the 6-minute walk distance, quality-of-life scores, or NT-proBNP levels.

CONCLUSIONS

Patients with heart failure and a preserved ejection fraction who received isosorbide mononitrate were less active and did not have better quality of life or submaximal exercise capacity than did patients who received placebo. (Funded by the National Heart, Lung, and Blood Institute; ClinicalTrials.gov number, NCT02053493.).

Investigation of the Hepato-Protective Effects of Imdur in a Rat Model of Chronic Mountain Sickness

BACKGROUND

The objective of this study was to determine if the clinical nitrate, Imdur, has a hepato-protective effect in chronic mountain sickness (CMS).

METHODS

A total of 60 SD rats were included in the study. Fifty rats were used to model CMS and were randomly divided into the following groups (10 rats per group): 1) plateau, 2) nifedipine, 3) low dose imdur, 4) moderate dose imdur, and 5) high dose imdur. The remaining 10 rats were used for the control group. Thirty days after the CMS model was established, according to the appropriate body weight of the rats, intragastric administration of the treatment groups commenced. After 15 days, changes in pulmonary artery pressure (PAP) and pathology of liver tissues were observed. Homocysteine (Hcy), interleukin-6 (IL-6), C-reactive protein (CRP), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione peroxidase (GSH-PX) levels were also measured.

RESULTS

Compared with the control group, the levels of PAP, Hcy, IL-6, CRP, and MDA of the rats in the plateau model group, nifedipine group, and imdur groups were elevated. The levels of SOD and GSH-PX in these groups decreased relative to the control group. The injured rat livers were observed under the light microscope, revealing that hypoxia had caused tissue damage. Compared with that of the plateau model group, the levels of PAP, Hcy, IL-6, CRP, and MDA of the rats in the high dose imdur group were decreased (p < 0.05), and the levels of SOD and GSH-PX were increased (p < 0.05). Except for IL-6, the other parameters were comparable to normal values and better than those of the nifedipine group. Liver tissue from the high dose imdur group demonstrated less tissue damage from pathological sections.

CONCLUSIONS

High dose imdur has hepato-protective effects in CMS rat models.

Cervical ripening before first trimester surgical evacuation for non-viable pregnancy

BACKGROUND

Medications or mechanical dilators are often used to soften and dilate the cervix prior to surgical evacuation of the uterus for non-viable pregnancy, or miscarriage. The majority of miscarriages occur in the first trimester. The aim of cervical ripening is to reduce the possibility of injury to the uterus and cervix and improve the surgical ease of the procedure. Cervical ripening agents can have adverse effects and it is uncertain as to whether these risks outweigh the benefits of their use.

OBJECTIVES

To systematically review the benefits and harms of using cervical ripening agents prior to surgical evacuation of non-viable pregnancy prior to 14 weeks' gestation.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 April 2015) and reference lists of retrieved papers.

SELECTION CRITERIA

Randomised controlled trials (published in full-text form, or as abstracts only), which assessed the use of pharmacological or mechanical agents to ripen the cervix in women undergoing dilation and curettage or vacuum aspiration for non-viable pregnancy at less than 14 weeks' gestation were eligible for inclusion. Cluster-randomised controlled trials and trials using a cross-over design were not eligible for inclusion.Unpublished randomised controlled trials and quasi-randomised trials would have been eligible for inclusion but none were identified.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. Data were checked for accuracy.

MAIN RESULTS

We included nine trials with 469 women. A diverse set of medications and regimens were studied in these trials, making the comparisons available for meta-analysis limited. The comparisons draw data from six trials with 383 participants. All trials were relatively small and had several aspects of unclear risk of bias with few of this review's outcomes reported. Due to this, no data from three trials were able to be used despite them meeting inclusion criteria.We carried out four comparisons: isosorbide mononitrate or dinitrate compared with misoprostol; misoprostol compared with placebo; chemical dilation (use of medications) compared with mechanical dilation; and any cervical preparation compared with placebo.None of the included studies reported data on the review's primary outcome: cervical or uterine injury (perforation, laceration, creation of a false passage).No clear difference was shown between isosorbide compounds and misoprostol for the outcome need for manual cervical dilation (average risk ratio (RR) 0.76, 95% confidence interval (CI) 0.10 to 5.64; three trials, 150 women; Tau² = 2.11; I² = 69%), however the data were heterogenous. In terms of adverse effects, misoprostol was associated with more vomiting (RR 0.11, 95% CI 0.01 to 0.85; two trials, 120 women), however there were no clear differences between isosorbide compounds and misoprostol in relation to other reported adverse effects (headache, nausea or hypotension). The dosing regimens differed in terms of dose, number of administrations and route of administration in the different trials. Mechanical (Dilapan-S hygroscopic) dilators performed similarly to chemical dilators in a single trial (65 women) that measured difficulty in cervical dilation, excessive bleeding and adverse effects.Misoprostol was shown to be more effective than placebo for cervical ripening (reduced need for manual cervical dilation) (RR 0.14, 95% CI 0.08 to 0.26; one trial, 120 women), and surgical time was reduced when misoprostol was used (mean difference (MD) -3.15, 95% CI -3.59 to -2.70; one trial, 120 women). However, compared to placebo, misoprostol, was associated with more abdominal pain (RR 29.00, 95% CI 1.77 to 475.35; one trial, 120 women), although no clear differences in the risk of other adverse effects (nausea, vomiting, headache or fever) were observed between groups.There was no clear differences between chemical dilation and mechanical dilators for the outcomes: difficulty in cervical dilation, excessive bleeding or adverse effects.Compared with placebo, any cervical preparation reduced the need for manual cervical dilatation (average RR 0.25, 95% CI 0.07 to 0.89; two trials, 168 women; Tau² = 0.67; I² = 81%), and reduced surgical time (MD -2.55, 95% CI -3.67 to -1.43, two trials, 168 women; Tau² = 0.63; I² = 96%).None of the included trials reported on the review's other secondary outcomes, including: injury to bladder or bowel, miscarriage/preterm birth in a subsequent pregnancy, analgesia use after administration of ripening agent but before surgery, or analgesia use after surgery.

AUTHORS' CONCLUSIONS

This review found no evidence to evaluate cervical ripening prior to first trimester surgical evacuation for miscarriage for reducing the rate of cervical or uterine injury, however, this may be because these outcomes are very rare. Cervical preparation was shown to reduce the need for manual cervical dilatation compared with placebo.Misoprostol and isosorbide mononitrate and dinitrate were similarly effective in ripening the cervix, however there was more vomiting with misoprostol. Mechanical (Dilapan-S hygroscopic) dilators performed similarly to chemical dilators.The nine studies included in this review were small and the methodological quality of the trials was mixed, and for the most part, not well-described; thus any conclusions drawn from the data included in this review must be treated with caution. Consequently, large, high-quality trials are required to determine whether the benefits of this treatment outweigh the risks. Further research should be powered to assess the rate of cervical and uterine injury between interventions. Future research should also guide clinicians in deciding whether the benefits of reduced manual cervical dilatation outweigh the risks of adverse effects associated with these agents (nausea, vomiting, headache, fever, diarrhoea and pain). Women's satisfaction and outcomes of future pregnancies should also be assessed.

[Comparative Assessment of Effects of Isosorbide Dinitrate, Isosorbide-5-Mononitrate and Nicorandil on the Frequency of Angina Attacks and Vasoregulating Endothelial Function in Patients With Ischemic Heart Disease]

to compare effects of isosorbide dinitrate, isosorbide-5-mononitrate and nicorandil on frequency of angina attacks and vasoregulating endothelial function in patients with ischemic heart disease (IHD). MATERIAL AND METHODS. In 117 patients with stable II-III functional class angina we analyzed frequency of angina attacks, exercise tolerance, data of 24-hour Holter ECG monitoring and brachial artery Doppler study. RESULTS. Patients with IHD had impaired endothelium-dependent vasodilation in the form of reduced endothelial response to increase of "shear stress" during test with reactive hyperemia. Long-term therapy with isosorbide dinitrate, isosorbide-5-mononitrate, and nicorandil was associated with normalization of endothelium-dependent vasodilation of the brachial artery. This effect was more pronounced during therapy with nicorandil.

Relationship between Nitrate-Induced Headache and Coronary Artery Lesion Complexity

OBJECTIVE

The aim of the present study was to investigate the association between nitrate-induced headache (NIH) and the complexity of coronary artery lesions in patients with stable coronary artery disease (CAD).

SUBJECTS AND METHODS

Two hundred and seventy-five patients with anginal chest pain who underwent coronary angiography were enrolled in the present study. NIH was defined as the presence of headache due to nitrate treatment (isosorbide mononitrate 40 mg) after excluding confounding factors. Coronary artery lesion complexity was assessed by the SYNTAX score (SXscore) using a dedicated computer software system.

RESULTS

The mean SXscore was lower in the patients with NIH than in patients without NIH (7.3 ± 5.2 vs. 14.4 ± 8.5, respectively; p < 0.001). Additionally, patients with NIH had a lower rate of multivessel disease compared with those without NIH (the mean number of diseased vessels was 1.5 ± 0.7 and 2.0 ± 07, respectively; p < 0.001). In multivariate analysis, increasing age (p = 0.02) and headache (p = 0.001) were found to be independent determinants of SXscore.

CONCLUSION

The present study demonstrated an independent inverse association between NIH and SXscore. The NIH could provide important predictive information about coronary artery lesion complexity in patients with stable CAD.

The effect of peroxynitrite decomposition catalyst MnTBAP on aldehyde dehydrogenase-2 nitration by organic nitrates: role in nitrate tolerance

Bioconversion of glyceryl trinitrate (GTN) into nitric oxide (NO) by aldehyde dehydrogenase-2 (ALDH-2) is a crucial mechanism which drives vasodilatory and antiplatelet effect of organic nitrates in vitro and in vivo. Oxidative stress generated by overproduction of free radical species, mostly superoxide anions and NO-derived peroxynitrite, has been suggested to play a pivotal role in the development of nitrate tolerance, though the mechanism still remains unclear. Here we studied the free radical-dependent impairment of ALDH-2 in platelets as well as vascular tissues undergoing organic nitrate ester tolerance and potential benefit when using the selective peroxynitrite decomposition catalyst Mn(III) tetrakis (4-Benzoic acid) porphyrin (MnTBAP). Washed human platelets were made tolerant to nitrates via incubation with GTN for 4h. This was expressed by attenuation of platelet aggregation induced by thrombin (40U/mL), an effect accompanied by GTN-related induction of cGMP levels in platelets undergoing thrombin-induced aggregation. Both effects were associated to attenuated GTN-induced nitrite formation in platelets supernatants and to prominent nitration of ALDH-2, the GTN to NO metabolizing enzyme, suggesting that GTN tolerance was associated to reduced NO formation via impairment of ALDH-2. These effects were all antagonized by co-incubation of platelets with MnTBAP, which restored GTN-induced responses in tolerant platelets. Comparable effect was found under in in vivo settings. Indeed, MnTBAP (10mg/kg, i.p.) significantly restored the hypotensive effect of bolus injection of GTN in rats made tolerants to organic nitrates via chronic administration of isosorbide-5-mononitrate (IS-5-MN), thus confirming the role of peroxynitrite overproduction in the development of tolerance to vascular responses induced by organic nitrates. In conclusion, oxidative stress subsequent to prolonged use of organic nitrates, which occurs via nitration of ALDH-2, represents a key event in GTN tolerance, an effect counteracted both in vitro and in vivo by novel peroxynitrite decomposition catalyst.

Liposome-encapsulated ISMN: a novel nitric oxide-based therapeutic agent against Staphylococcus aureus biofilms

Background

Staphylococcus aureus in its biofilm form has been associated with recalcitrant chronic rhinosinusitis with significant resistance to conventional therapies. This study aims to determine if liposomal-encapsulation of a precursor of the naturally occurring antimicrobial nitric oxide (NO) enhances its desired anti-biofilm effects against S. aureus, in the hope that improving its efficacy can provide an effective topical agent for future clinical use.

Methodology

S. aureus ATCC 25923 biofilms were grown in-vitro using the Minimum Biofilm Eradication Concentration (MBEC) device and exposed to 3 and 60 mg/mL of the NO donor isosorbide mononitrate (ISMN) encapsulated into different anionic liposomal formulations based on particle size (unilamellar ULV, multilamellar MLV) and lipid content (5 and 25 mM) at 24 h and 5 min exposure times. Biofilms were viewed using Live-Dead Baclight stain and confocal scanning laser microscopy and quantified using the software COMSTAT2.

Results

At 3 and 60 mg/mL, ISMN-ULV liposomes had comparable and significant anti-biofilm effects compared to untreated control at 24 h exposure (p = 0.012 and 0.02 respectively). ULV blanks also had significant anti-biofilm effects at both 24 h and 5 min exposure (p = 0.02 and 0.047 respectively). At 5 min exposure, 60 mg/mL ISMN-MLV liposomes appeared to have greater anti-biofilm effects compared to pure ISMN or ULV particles. Increasing liposomal lipid content improved the anti-biofilm efficacy of both MLV and ULVs at 5 min exposure.

Conclusion

Liposome-encapsulated “nitric oxide” is highly effective in eradicating S. aureus biofilms in-vitro, giving great promise for use in the clinical setting to treat this burdensome infection. Further studies however are needed to assess its safety and efficacy in-vivo before clinical translation is attempted.

Combined therapies versus monotherapies for the first variceal bleeding in patients with high-risk varices: a meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The effect of combined therapies (among non-selected beta-blockers [NSBB], endoscopic therapy, and other treatments) on the first variceal bleeding has been evaluated in several randomized controlled trials previously, and the results were controversial. We performed this meta-analysis to assess the effect of combined therapies in patients with high-risk varices without previous variceal bleeding.

METHODS

The Cochrane Library, The Cochrane Hepato-Biliary Group Controlled Trials Register, MEDLINE, and EMBASE were searched for eligible trials. Manual searches were also performed for additional studies. Upper gastrointestinal bleeding, variceal bleeding, mortality, and adverse events were evaluated as end-points by meta-analysis.

RESULTS

Twelve randomized controlled trials with 1571 patients were included. Compared with the NSBB (propranolol or nadolol) or endoscopic therapy alone, all of the combined therapies did not demonstrate significant improvements in variceal bleeding, total upper gastrointestinal bleeding, and mortality. Only the combinations of isosorbide-mononitrate or spironolactone with NSBB tended to decrease the risk of variceal bleeding when compared with the use of NSBB alone (isosorbide-mononitrate plus NSBB vs NSBB: odds ratio = 0.67, 95% confidence interval 0.40-1.13, P = 0.13; spironolactone plus NSBB vs NSBB: odds ratio = 0.41, 95% confidence interval 0.10-1.69, P = 0.22). Adverse events were more frequently observed in the combined therapy groups.

CONCLUSIONS

Based on the available evidences, no combined therapy can be recommended as the first-line treatment for the primary prevention of variceal bleeding currently. Further studies with large sample sizes and long-term follow up are warranted.

Evaluation of novel immediate-/controlled-release tablets of isosorbide-5-mononitrate (5-ISMN): in vitro-in vivo correlation

The aim of the present study was to develop the novel immediate-controlled release (ICR) tablets of isosorbide-5-mononitrate (5-ISMN) composed of an osmotic pump tablet core coated with an immediate-release layer. The novel ICR tablets of 5-ISMN could release drug quickly and continuously through a semi-permeable membrane (SPM) composed of ethylcellulose (EC)/polyethylene glycol (PEG) 4000 and cellulose acetate (CA)/PEG4000. Release tended to decrease with storage time. However, the drug release rates changed little for the SPM composed of EC/PVP K30. The weight loss test also confirmed these results. The major release mechanism was diffusion according to the Higuchi equation. The relative bioavailability of the ICR tablets compared to the reference formulation in the single and multiple dose regiments were 90.9 and 111.2%, respectively. They were both bioequivalent to the reference formulation. In vitro-in vivo correlation (IVIVC) studies demonstrated that the dissolution in vitro simulated the absorption in vivo well. In general, 5-ISMN ICR tablets composed of an osmotic pump tablet core and an immediate-release layer may be promising in providing immediate and constant drug delivery with minimum fluctuations during long storage time.

[The effects and its mechanism of N-arginine chitosan as transdermal enhancer]

The purpose of this study is to investigate the penetration effects and mechanism of N-arginine chitosan (ACS). This novel transdermal enhancer with a mimetic structure of cell-penetration peptides was synthesized by introducing hydrophilic arginine groups to the amino-group on chitosan's side chain. The structure of ACS was confirmed by FT-IR, 1H NMR and element analysis. In addition, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used to study the protein conformation and the water content of stratum corneum, and the result suggested that ACS can change the orderly arrangement of the molecules in the stratum corneum, making the stack structure of keratin become loose. And ACS can increase the water content of the stratum corneurn. Inverted fluorescence microscope and flow cytometry were used to examine penetration effect of ACS on Hacat cell. The result confirmed that the uptake of ACS was enhanced with increased substitution degree of arginine by 4-8 folds compared to chitosan. In vitro penetration studies on three electrical types of drugs were carried out using three model drugs of negatively charged aspirin, positively charged terazosin and neutral drug isosorbide mononitrate by the method of Franz diffusion cells. The results showed that ACS has obviously penetration of the negatively charged drug aspirin, and certain penetration of neutral drug issorbide mononitrate, but inhibition of positively charged terazosin. In vivo imaging technology research results show that the ACS can significantly enhance the fluorescence intensity of morin, which is the auto-fluorescence anionic drug. These obtained results suggested that ACS, as a promising transdermal enhancer, can change the structure of the keratinocytes and analog penetrating peptides promote absorption, but have certain selectivity for the drug.

Effects of propranolol or propranolol plus isosorbide-5-mononitrate on variceal pressure in schistosomiasis

AIM: To compare the effects of propranolol (PR) to that of PR plus isosorbide-5-mononitrate (ISMN) on variceal pressure in patients with schistosomiasis.

METHODS: Forty-eight patients with schistosomiasis who had no previous variceal bleeding were treated with PR alone or PR plus ISMN. Seven patients refused variceal pressure manometry (3 receiving PR and 4 receiving PR plus ISMN). One patient withdrew from the trial due to headache after taking ISMN. At the time of termination, twenty patients were randomly assigned to treatment with PR plus ISMN or PR alone. The dose of PR was adjusted until the resting heart rate had been reduced by 25% or was less than 55 bpm. In the PR plus ISMN group, after PR was titrated to the same target, the dose of ISMN was increased up to 20 mg orally twice a day. Variceal pressure was measured using a noninvasive endoscopic balloon technique at the end of the 6-mo treatment period.

RESULTS: In 40 patients (20 in the PR group and 20 in the PR plus ISMN group), variceal pressure was measured before treatment and at the end of the 6-mo treatment period. PR or PR plus ISMN treatment caused a significant reduction in variceal pressure (PR group: from 24.15 ± 6.05 mmHg to 22.68 ± 5.70 mmHg, P = 0.001; PR plus ISMN group: from 25.69 ± 5.26 mmHg to 20.48 ± 5.43 mmHg; P < 0.001). The percentage decrease in variceal pressure was significant after PR plus ISMN compared with that after PR alone (15.93% ± 8.37% vs 6.05% ± 3.67%, P = 0.01). One patient in the PR plus ISMN group and two patients in the PR group had variceal bleeding during follow-up. There were no significant differences between the two groups regarding the incidence of variceal bleeding. In the PR plus ISMN group, three patients had headache and hypotension. The headache was mild and transient and promptly disappeared after continuation of the relevant drug in two patients. Only one patient withdrew from the trial due to severe and lasting headache after taking ISMN. No side effects occurred in the PR group.

CONCLUSION: PR plus ISMN therapy may be an alternative treatment for patients with schistosomiasis who have a high risk of bleeding.

Organic nitrates favor regression of left ventricular hypertrophy in hypertensive patients on chronic peritoneal dialysis

The aim of the study was to evaluate the effect of nitrates on left ventricular hypertrophy (LVH) in hypertensive patients on chronic peritoneal dialysis (PD). Sixty-four PD patients with hypertension were enrolled in this study. All patients accepted antihypertensive drugs at baseline. Thirty-two patients (nitrate group) took isosorbide mononitrate for 24 weeks. The remaining 32 patients (non-nitrate group) took other antihypertensive drugs. Blood pressure (BP), left ventricular mass index (LVMI) and plasma asymmetric dimethylarginine (ADMA) were monitored. Subjects with normal renal function were included as the control group (n = 30). At baseline, plasma ADMA levels in PD patients were significantly higher than the control group, but there was no significant difference in plasma ADMA levels between the two groups. At the end of the 24-week period, BP, LVMI, LVH prevalence and plasma ADMA levels in the nitrate group were significantly lower than those in the non-nitrate group. BP did not show a significant difference between 12 and 24 weeks in the nitrate group with a reduced need for other medication. Logistic regression analysis showed that nitrate supplementation and SBP reduction were independent risk factors of LVMI change in PD patients after adjusting for age, gender, diabetes history and CCB supplementation. It was concluded that organic nitrates favor regression of LVH in hypertensive patients on chronic peritoneal dialysis, and nitrates may be considered for use before employing the five other antihypertensive agents other than nitrates.

[Autonomous pharmacodynamics of organic nitrates in patients with unstable angina]

The pharmacological test with the use of high-resolution rhythmocardiography for the analysis of cardiac rhythm variability associated with peripheral vegetative regulation of the synoatrial node was applied to study effects of a single dose of organic nitrates (nitroglycerin and mononitrate isosorbide) in 41 patients with unstable angina. Rhythmocardiograms were obtained before and after a morning sublingual dose of nitrates preceding intake of basal drugs. The results suggest negative action of nitrates on peripheral vegetative regulation of pacemaker activity of the synoatrial node.

In vitro dissolution and in vivo bioequivalence evaluation of two brands of isosorbide 5-mononitrate sustained release tablets

The purpose of the present study was to test a sustained release-tablet newly formulated with synthetic paraffin and compare its bioequivalence to that of the Imdur® Long-Acting tablet, based on the guidelines of the Korean Food and Drug Administration.Dissolution test was performed in 4 different dissolution media. A LC/MS/MS method of isosorbide 5-mononitrate in human plasma was validated. In vivo bioequivalence tests of the 2 isosorbide 5-mononitrate tablets were performed in both preprandial and postprandial states.A comparative dissolution test gave similar results for both tablets in all dissolution media tested: 40% dissolution in pH 1.2 at 2 h and 80% dissolution in pH 4.0, pH 6.8, or water at 10 h. In a bioequivalence study to compare 2 tablets, the mean total area under the curve (AUCt) and peak concentration (Cmax) in the fasted state were 8 476.0 ng · h/mL and 540.4 ng/mL, respectively, for the Imdur® Long Acting Tablet 60 mg, and 8 701.4 ng · h/mL and 564.2 ng/mL, respectively, for the test tablet. The mean AUCt and Cmax in the fed state were 8 793.5 ng · h/mL and 559.9 ng/mL, respectively, for the Imdur® Long-Acting tablet 60 mg, and 8 639.8 ng · h/mL and 617.9 ng/mL, respectively, for the test tablet. The 90% confidence intervals using log transformed data were within the acceptable range of 0.8 - 1.25.Based on these statistical analyses, we conclude that the test tablet is bioequivalent to the Imdur® Long-Acting tablet 60 mg in both the preprandial and postprandial states.

A randomized phase II study of irinotecan plus cisplatin versus irinotecan plus capecitabine with or without isosorbide-5-mononitrate in advanced non-small-cell lung cancer

BACKGROUND

We investigated the efficacy of irinotecan/cisplatin (IP) versus irinotecan/capecitabine (IX) with or without isosorbide-5-mononitrate (ISMN) in chemo-naïve advanced non-small-cell lung cancer.

PATIENTS AND METHODS

Initially, 74 patients were randomly assigned to either IP or IX. Given the potential benefits of ISMN on chemotherapy, the protocol was amended during the study. Subsequently, 72 patients were randomly assigned to either IP + ISMN or IX + ISMN. Patients were treated with predefined second-line therapies (docetaxel/capecitabine for IP or IP + ISMN, docetaxel/cisplatin for IX or IX + ISMN) when disease progressed.

RESULTS

A total of 146 received treatment. Response rate (RR), median progression-free survival (PFS) and overall survival (OS) were 49%, 5.5 months, 14.5 months in IP; 33%, 3.3 months, 13.0 months in IP + ISMN; 30%, 4.3 months, 16.1 months in IX; and 25%, 3.4 months, 13.6 months in IX + ISMN, respectively. While IP arm showed a trend toward higher RR and longer PFS than IX arm, IX arm showed a trend toward longer OS than IP arm. No significant differences were observed between IP + ISMN and IX + ISMN.

CONCLUSION

IP showed better RR and PFS but no OS benefit when compared with IX. The addition of ISMN to IP or IX chemotherapy did not seem to improve the treatment outcome.

In vitro and in vivo evaluation of novel osmotic pump tablets of isosorbide-5-mononitrate containing polyvinyl pyrrolidone (PVP) for controlled release

A novel osmotic pump tablet with ethyl cellulose (EC) and polyvinyl pyrrolidone (PVP) as the semipermeable membrane and isosorbide-5-mononitrate (5-ISMN) as the model drug was formulated in this study. Zero order release kinetics were attained by avoiding aging during storage. Drug release increased with an increase in the percentage of PVP K30 in the semipermeable membrane. However, drug release decreased with increased coating weight. Drug release rates decreased continuously for tablets coated with EC/PEG4000 and cellulose acetate (CA)/PEG4000. This tendency was more marked with longer storage time. However, there was little change in drug release rates for tablets with a semipermeable membrane of EC/PVP K30 at 6, 12 or 24 months. The weight loss test also validated the results mentioned above. The relative bioavailability of the osmotic-pump tablets against the reference formulation in single and multiple dose regimens was 116.7 and 106.5, respectively. This means that the bioavailability of osmotic pump tablets using PVP as the plasticiser was equal to that of the reference formulation. In general, 5-ISMN osmotic pump tablets with a semipermeable membrane composed of EC/PVP K30 may be useful in providing constant drug delivery with minimum fluctuations during longer storage time.

Comparative evaluation of isosorbide mononitrate and alendronate in management of postmenopausal osteoporosis

BACKGROUND

Osteoporosis, a skeletal disorder that adversely affects bone strength , is common among postmenopausal women primarily due to reduced ovarian estrogens.

PURPOSE

The present study was taken up to evaluate the role of isosorbide mononitrate (IMN) in the management of postmenopausal osteoporosis and to compare its efficacy with that of alendronate.

METHODS

This prospective systematic randomized study was conducted on 90 postmenopausal women with lumbar spine BMD >2.5 SD below the young adult reference range. The participants received either Tab Alendronate 70 mg orally, once weekly (Group I) or Tab IMN 40 mg orally once daily (Group II) for 9 months, in addition to 500 mg of oral calcium daily. The BMD of the lumbar spine was measured using DEXA scan at enrolment and after 9 months. The data was analyzed by Student's t test and Chi-square test.

RESULTS

The mean baseline BMD was 0.67 + 0.097 and 0.68 + 0.067 g/cm(2) in Group I and II, respectively. An increase of 11.94% in the mean BMD was noted after 9 months of treatment with alendronate as against 8.82% with IMN. Headache, flushing and palpitations in Group II and nausea, epigastric pain and heart burn in Group I were the most common adverse effects.

CONCLUSION

IMN has a beneficial effect on bone turnover in cases of postmenopausal osteoporosis and that the effect is comparable to that of alendronate. IMN is a promising and safe alternative to alendronate for the management of postmenopausal osteoporosis.

Interruption of a study of cervical ripening with isosorbide mononitrate due to adverse effects

PURPOSE OF INVESTIGATION

The objective of this study was to evaluate cervix length and the presence of cervical gland area (CGA) in ultrasounds performed before and after the administration of vaginal isosorbide mononitrate (IMN) for cervical ripening.

METHODS

We performed an observational, descriptive, and longitudinal study of pregnant patients indicated for labor induction and with a Modified Bishop Score (MBS) lower than six. For cervical ripening, 40 mg of vaginal IMN was administered at 0, 16, and 24 hours after the initiation of cervix preparation.

RESULTS

After enrolling 11 patients, the study had to be discontinued due to adverse effects. Three patients requested that they be withdrawn. Headaches were reported by all patients. Nausea, dizziness, dyspnea, and vomiting were also reported. The average cervical lengths at 0, 16, 24 and 36 hours were 27.6, 27.7, 25.9, and 23.0 mm, respectively. CGA disappeared in one of seven patients.

CONCLUSIONS

The use of IMN appears to increase the MBS, slightly reducing cervical length without altering the appearance of CGA. Considering the importance of maternal wellbeing during labor, the routine use of IMN cannot be recommended for cervical ripening in the third trimester due to the frequency and intensity of side-effects.

Vascular dysfunction in experimental diabetes is improved by pentaerithrityl tetranitrate but not isosorbide-5-mononitrate therapy

OBJECTIVE

Diabetes is associated with vascular oxidative stress, activation of NADPH oxidase, and uncoupling of nitric oxide (NO) synthase (endothelial NO synthase [eNOS]). Pentaerithrityl tetranitrate (PETN) is an organic nitrate with potent antioxidant properties via induction of heme oxygenase-1 (HO-1). We tested whether treatment with PETN improves vascular dysfunction in the setting of experimental diabetes.

RESEARCH DESIGN AND METHODS

After induction of hyperglycemia by streptozotocin (STZ) injection (60 mg/kg i.v.), PETN (15 mg/kg/day p.o.) or isosorbide-5-mononitrate (ISMN; 75 mg/kg/day p.o.) was fed to Wistar rats for 7 weeks. Oxidative stress was assessed by optical methods and oxidative protein modifications, vascular function was determined by isometric tension recordings, protein expression was measured by Western blotting, RNA expression was assessed by quantitative RT-PCR, and HO-1 promoter activity in stable transfected cells was determined by luciferase assays.

RESULTS

PETN, but not ISMN, improved endothelial dysfunction. NADPH oxidase and serum xanthine oxidase activities were significantly reduced by PETN but not by ISMN. Both organic nitrates had minor effects on the expression of NADPH oxidase subunits, eNOS and dihydrofolate reductase (Western blotting). PETN, but not ISMN, normalized the expression of GTP cyclohydrolase-1, extracellular superoxide dismutase, and S-glutathionylation of eNOS, thereby preventing eNOS uncoupling. The expression of the antioxidant enzyme, HO-1, was increased by STZ treatment and further upregulated by PETN, but not ISMN, via activation of the transcription factor NRF2.

CONCLUSIONS

In contrast to ISMN, the organic nitrate, PETN, improves endothelial dysfunction in diabetes by preventing eNOS uncoupling and NADPH oxidase activation, thereby reducing oxidative stress. Thus, PETN therapy may be suited to treat patients with cardiovascular complications of diabetes.

Treatment with LA-419 prevents monocrotaline-induced pulmonary hypertension and lung injury in the rat

We evaluated the therapeutic potential of LA-419, a hybrid organic nitrate that donates nitric oxide and thiol groups, to improve pulmonary arterial hypertension in an experimental model induced by monocrotaline in the rat. Treatment with LA-419 from the first day after monocrotaline administration prevented the increase in pulmonary pressure as well as the increases in ventricle/body weight and pulmonary artery wall thickness. Administration of LA-419 after establishment of hypertensive status also resulted in an improvement of these parameters. Both preventive and therapeutic treatments reduced mortality. The antioxidant effect of LA-419 was comparable to that achieved with a-tocopherol. Pulmonary remodeling accomplished by LA-419 could be attributed to a balanced antioxidant effect associated with its nitric oxide/SH donor capability. Thus, LA-419 might represent a new therapeutic approach in severe pulmonary hypertension in humans.

The role of nitric oxide in the expression of renal aquaporin 2 in a cirrhotic rat model: does an AVP-independent mechanism exist for the regulation of AQP2 expression?

The aquaporin (AQP) water channel is expected to play a decisive role of hyponatremia and water retention in cirrhotic patients. Despite the importance of the water channel, however, previous findings vary widely when it concerns AQP2 of the kidneys in subjects with cirrhosis. The purpose of this study was to investigate the expression of AQP2 in the distal renal tubule in cirrhosis, and the presence of the nitric oxide-AQP2 signaling pathway as a possible vasopressin-aquaporin-independent pathway. Sixty male Wister rats were assigned to six groups: (1) control; (2) TAA (thioacetamide); (3) TAA with nitric oxide donor; (4) TAA with nitric oxide inhibitor; (5) TAA with HMG CoA reductase inhibitor; (6) TAA with tetrahydrobiopterin. Immunohistochemical staining for AQP2, real-time polymerase chain reaction (PCR) for AQP2 and 3, citrulline assay, and renal cGMP concentration were measured. The AQP2-positivity of cirrhotic rats were higher than the controls (P < 0.05). The AQP2-positivity decreased in the nitric oxide donor group, but the proportion rose back up when the subjects were injected with the nitric oxide inhibitor (P < 0.05). The expression of AQP2 and AQP3 mRNA was also found to show an increase in the cirrhotic group as compared with the normal controls (P < 0.05). The cirrhotic group administered with nitric oxide donor showed a significant decline in the expression of the mRNA. The control group's cGMP concentration was lower than that of the cirrhotic group (P < 0.05), but a comparison of the two groups injected with nitric oxide modulators, such as statin and BH4, did not show significant differences in the cGMP concentration level. The expression of AQP2 of the kidneys increased in the cirrhotic rats. AQP2 had relations to the activity changes of nitric oxide synthetase.

Use of organic nitrates and the risk of hip fracture: a population-based case-control study

CONTEXT

Use of organic nitrates has been associated with increased bone mineral density. Moreover, a large Danish case-control study reported a decreased fracture risk. However, the association with duration of nitrate use, dose frequency, and impact of discontinuation has not been extensively studied.

OBJECTIVE

Our objective was to evaluate the association between organic nitrates and hip fracture risk.

METHODS

A case-control study was conducted using the Dutch PHARMO Record Linkage System (1991-2002, n = 6,763 hip fracture cases and 26,341 controls). Cases had their first admission for hip fracture, whereas controls had not sustained any fracture after enrollment. Current users of organic nitrates were patients who had received a prescription within 90 d before the index date. The analyses were adjusted for disease and drug history.

RESULTS

Current use of nitrates was not associated with a decreased risk of hip fracture [adjusted odds ratio (OR) = 0.93; 95% confidence interval (CI) = 0.83-1.04]. Those who used as-needed medication only had a lower risk of hip fracture (adjusted OR = 0.83; 95% CI = 0.63-1.08) compared with users of maintenance medication only (adjusted OR = 1.17; 95% CI = 0.97-1.40). No association was found between duration of nitrate use and fracture risk.

CONCLUSIONS

Our overall analyses showed that risk of a hip fracture was significantly lower among users of as-needed organic nitrates, when compared with users of maintenance medication. Our analyses of hip fracture risks with duration of use did not further support a beneficial effect of organic nitrates on hip fracture, although residual confounding may have masked beneficial effects.

Outpatient induction -- how safe

There is a world-wide interest in outpatient care. Induction of labor is commonly offered to women with prolonged pregnancy, and evidence from randomized controlled studies suggest that inpatient and outpatient induction achieve comparative maternal and fetal outcomes. However, safety data are very limited. Careful selections of appropriate patients as well as standardized monitoring protocols are essential before outpatient induction can be initiated. Uterine hyperstimulation with fetal heart rate deceleration and other maternal or fetal adverse events are rare but unpredictable. Unrecognized fetal hypoxia due to uterine contractions remains an unsolved problem after discharge from the hospital. The ideal method for outpatient cervical ripening is controversial. The local application of nitric oxide donors prior to induction might be a promising approach. Larger studies are necessary before widespread use of outpatient cervical ripening by prostaglandins or other cervical ripening agents can be advocated.

[Cardiotoxicity induced by 5-fluorouracil or capecitabine]

5-fluorouracil and capecitabine have significant antineoplastic activity towards various solid tumors. Cardiotoxicity causing angina, arrhythmia and infarction are serious adverse events associated with these agents. The pathogenesis is discussed and symptoms of cardiotoxicity, intervention with nitroglycerine and risk factors as cardiac comorbidity are described. Following cardiotoxicity, lack of alternative active agents may provide grounds to rechallenge with 5-FU. In this situation, dose-modified 5-FU-based chemotherapy supported by medical antiangina prevention is feasible.

Anti-anginal efficacy of a controlled-release formulation of isosorbide-5-mononitrate once daily in angina patients on chronic beta-blockade

The anti-anginal effect of a controlled-release (Durules) formulation of isosorbide-5-mononitrate (5-ISMN) 60 mg, Imdur, once daily was evaluated in a randomised double-blind, placebo-controlled, crossover study with a placebo run-in period. Each period lasted for 2 weeks. A total of 70 patients (58 men and 12 women) with stable exertional angina pectoris on beta-blockade, mean age 59 years (range 39-71), were included. Exercise testing was performed on a bicycle ergometer 3 hours after the dose at the end of each period. Anginal attacks and intake of sublingual nitroglycerin tablets were noted. Imdur in combination with a beta-blocker significantly increased the total exercise capacity, the time and total work until the onset of chest pain and at 1 mm ST-depression compared with beta-blockade alone. The attack rate and the nitroglycerin consumption were significantly decreased. Headache was the only significant side-effect. In conclusion, the addition of Imdur once daily to beta-blockade significantly increased the anti-anginal effect.

Early identification of haemodynamic response to pharmacotherapy is essential for primary prophylaxis of variceal bleeding in patients with 'high-risk' varices

BACKGROUND

A beta-blocker is recommended for primary prophylaxis of variceal bleeding; however, only one-third have hepatic venous pressure gradient (HVPG) response. The role of addition of isosorbide-5-mononitrate (ISMN) to beta-blocker and benefits of HVPG-guided 'a la carte' approach remain unclear.

AIM

To determine the benefits of HVPG-guided pharmacotherapy in primary prophylaxis of variceal bleeding using beta-blocker and ISMN.

PATIENTS AND METHODS

Consecutive patients of cirrhosis, with high-risk varices, with no previous variceal bleeding were included. After baseline HVPG, patients received incremental propranolol to achieve HR of 55/min. After one-month, HVPG was repeated to determine response (<12 mmHg or >or=20% reduction). ISMN was added in nonresponders and HVPG repeated. Patients were followed up for 24 months.

RESULTS

Of 56 patients (age 47 +/- 13, males 79%) from 89 eligible patients, 21 (38%) responded to beta-blocker alone. Six additional patients responded to combination. Thus, overall 48% (27/56) patients responded. Variceal bleeding occurred in seven of 56 (13%) patients [one of 27 (4%) responder, five of 23 (22%) nonresponders and one of six (17%) with unknown response; P = N.S.]. The actuarial probability of variceal bleeding at median 24 months was 4% in responders and 22% in nonresponders (P < 0.05). Ten (18%) patients developed adverse effects to propranolol and six of 35 (17%) to nitrates requiring dose reduction. Risk factors of variceal bleed were grade IV varices and haemodynamic nonresponse.

CONCLUSIONS

For primary prophylaxis, a beta-blocker is effective in 38% and addition of ISMN raises the response rate to about half of patients. The HVPG-guided 'a la carte' approach may be considered for these patients.

LA-419, a nitric-oxide donor for the treatment of cardiovascular disorders

LA-419, currently being developed by Lacer SA, is a thiol-containing analog of isosorbide mononitrate that is undergoing assessment in clinical trials for the treatment of chronic ischemic cardiovascular disorders. The compound was originally designed to have a reduced tendency toward tolerance sensitivity - a major limitation of established organic nitrate compounds. The rationale behind the drug design was to include an antioxidant moiety in the drug structure to combat the contribution of oxidative stress in tolerance induction. The compound is at an early stage of development, but has already provided some surprising data. First, LA-419 does not appear to require the nitroxy ester moiety for activity and its actions might not be mediated only by nitric oxide release. Second, unlike conventional nitrates, LA-419 is active in platelets, suggesting a potential role as an antithrombotic agent. Third, LA-419 has a profound impact on left ventricular hypertrophy, making the drug a plausible candidate for several additional potential therapeutic opportunities. In addition, LA-419 has demonstrated potential in the treatment of glaucoma and intestinal disorders. At the time of publication, LA-419 was in phase II clinical trials in patients with chronic ischemic cardiovascular disorders.

[Synthesis and cardioprotective effect of a novel anti-ischemic/reperfused injury compound]

The aim of present study is to investigate the cardioprotective effect of a new compound acetyl ferulaic isosorbide (AFI), composed of ferulaic acid (FA) and isosorbide mononitrate (ISMN) by esterification in myocardial ischemia/reperfusion (MI/R). Male Sprague-Dawley rats, subjected to 30 minutes of myocardial ischemia and 3 hours of reperfusion, randomly received one of the following treatments separately: SHAM, I/R (MI/R + solvent), SF (MI/R+SF, 40 mg x kg(-1), ig), ISMN (MI/R + ISMN, 30 mg x kg(-1), ig), SF + ISMN (MI/R + SF + ISMN, 40 mg x kg(-1) + 30 mg x kg(-1), ig) and AFI (MI/R + AFI, 10 mg x kg(-1), ig). Left ventricle developed pressures (LVDP) and the maximal first derivative of developed pressure ( +/-dP / dtmax) were monitored throughout the experiments. Myocardial infarction size, serum creatine kinase (CK) activity, lactate dehydrogenase (LDH) activity, superoxide dismutase (SOD) activity, hydrogen peroxide (H2O2), malondialdehyde (MDA) and nitric oxide (NO) production were determined at the end of reperfusion. Compared with SF, ISMN or SF + ISMN treatment groups, AFI treatment decreased infarction size (n=8, P < 0.01), improved cardiac function as evidenced by increased LVDP and +/- dP/dtmax (n=8, P < 0.05), increased serum SOD activity, reduced serum CK and LDH activities, H2O2 and MDA production (n=8, P < 0.05). The new compound AFI showed a stronger cardioprotective effect against MI/R injury than SF, ISMN or their combined administration did.

Isosorbide mononitrate versus alendronate for postmenopausal osteoporosis

OBJECTIVE

To compare the effectiveness, safety, and affordability of isosorbide mononitrate with alendronate for postmenopausal osteoporosis.

METHODS

A randomized controlled trial of 60 postmenopausal women with osteoporosis. Participants were randomly assigned to receive either 20 mg daily of isosorbide mononitrate or 70 mg weekly of alendronate for 12 months. Bone mineral density (BMD) was measured using dual X-ray absorptiometry (DXA) at baseline and after 12 months.

RESULTS

Both groups showed significant improvement in BMD. Isosorbide mononitrate yielded a comparable effect to alendronate for BMD and T-score at the end of the follow-up period. For BMD and T score the mean differences between the 2 groups were -0.005 (95% CI, -0.02 to 0.03) and 0.31 (95% CI, -0.03 to 0.64), respectively. A 10.8% and 12.1% change in BMD after 12 months was seen for isosorbide mononitrate and alendronate, respectively.

CONCLUSION

Isosorbide mononitrate is comparable to alendronate. Nitric oxide donors may be an effective and affordable therapy to improve bone mineral density.

[Studies on preparation of isosorbide-5-mononitrate pulsatile controlled-release pellets and various influence factors]

We prepared the isosorbide-5-mononitrate pulsatile controlled-release pellets (PCRP) and studied the influencing factors in vitro. The isosorbide-5-mononitrate (5-ISMN) pellets prepared by extrusion-spheronization technology were coated with swelling material as the inner coating swelling layer, and with ethylcellulose aqueous dispersion as the outer coating controlled layer. The influences of the coating materials of the swelling layer, the coating levels of the swelling layer and controlled layer,and the pH values of the media on the release of 5-ISMN from PCRP were investigated. The drug release from the pellets was pulsatile. The ISMN-5-PCRP, with a lag time of 5 h and more than 80% released within the following 1.5 h,were prepared by using the low-substituted hydroxypropyl cellulose as the inner swelling layer with 15% (weight) in coating thickness, and the ethylcellulose aqueous dispersion as the outer controlling layer with 13% (weight) in coating thickness.

[Endothelium and nitric oxide]

Studied nature of the "blood vessels relaxing factor" derived from endothelium that was identified as nitric oxide caused intensive scientific research on nitric oxide regarding some aspects of its impact on human physiological and pathological processes. The objective of this short review is to discuss widely used (in the clinical practice) direct and indirect donors of nitric oxide and/or other agents, increasing nitric oxide concentration in human body, and their beneficial role for the prevention of atherosclerosis. Under physiological conditions, endothelium regulates the tone of blood vessels, homeostasis of which is maintained by endothelium-generated vasoconstrictors and vasodilators. The most important vasodilator and the main substance produced by the endothelium is nitric oxide. The failure of synthesis and/or the lost of nitric oxide bioavailability is the major feature of endothelial dysfunction and key factor initiating progression of atherosclerosis. The endothelial dysfunction initiates the series of events, which stimulate and aggravate the course of atherosclerosis by increasing endothelial permeability, platelet aggregation, and leukocyte adhesion, and cytokine expression. Further, the review deals with the mechanisms of action of statins, angiotensin-converting enzyme inhibitors, L-arginine, direct nitric oxide donors (nitroglycerin, isosorbide mononitrate and isosorbide dinitrate), and indirect nitric oxide donors (phosphodiesterase-V inhibitors, K(ATP) openers).

Isosorbide mononitrate vaginal gel versus misoprostol vaginal gel versus Dilapan-S for cervical ripening before first trimester curettage

OBJECTIVE

To compare the efficacy and safety of vaginal applications of three different principles of cervical priming prior to first trimester curettage, isosorbide mononitrate (ISMN), misoprostol and Dilapan-S, a hygroscopical cervical dilator.

STUDY DESIGN

Pregnant women with missed abortion between 6 and 12 gestational weeks were included and randomly assigned to receive either 80 mg ISMN vaginal gel (group 1) or 200 microg of misoprostol vaginal gel (group 2) or Dilapan-S, a hygroscopical cervical dilator (group 3), for cervical ripening before curettage. Outcome parameters were cervical dilation at the time of operation and maximum dilation reached with Hegar's dilator and the degree of difficulty in mechanical dilation as well as safety and side effects of the preparations.

RESULTS

Sixty-five pregnant women with missed abortion were included and assigned to the three study groups (n=22 for group 1, n=22 for group 2, n=21 for group 3). Misoprostol vaginal gel and Dilapan-S were significantly more effective than ISMN vaginal gel in cervical dilation reached with priming (p<0.005 and p<0.005) and in the degree of difficulty in cervical dilation assessed by the surgeon (p<0.001 and p<0.01). Mild discomfort was indicated by all patients after Dilapan insertion, whereas no patient complained about discomfort after misoprostol or ISMN insertion (p<0001). Three patients suffered from mild hypotension and headache after ISMN treatment, and two had increased vaginal bleeding due to uterine atony during surgery (p<0.05).

CONCLUSION

A vaginal gel of ISMN is less effective for cervical ripening prior to first trimester curettage compared to misoprostol vaginal gel or Dilapan-S. The latter could be an effective and safe alternative to prostaglandin priming avoiding preoperative contractions caused by prostaglandin preparations.