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1.
Int J Radiat Oncol Biol Phys ; 118(3): 616-625, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-37742773

ABSTRACT

PURPOSE: There is currently no gold standard for the management of acute radiation enteritis. We compared the efficacy and safety of Racecadotril, an anti-hypersecretory drug, versus Loperamide, an anti-motility agent, in acute radiation enteritis. METHODS AND MATERIALS: We conducted a randomized, double-masked, non-inferiority trial at a single research institute. Patients receiving curative radiation for pelvic malignancies, who developed grade 2 or 3 diarrhea (as per Common Terminology Criteria for Adverse Events, v 4.0) were included in the study. Patients in the intervention arm received Racecadotril and placebo. Patients in the control arm received Loperamide and placebo. The primary outcome was the resolution of diarrhea, 48 hours after the start of treatment. RESULTS: 162 patients were randomized between 2019 and 2022. On intention-to-treat analysis, 68/81 patients, 84%, (95% CI, 74.1%-91.2%) in the Racecadotril arm and 70/81, 86.4%, (95% CI, 77.0%-93.0%) in the Loperamide arm improved from grade 2 or 3 diarrhea to grade 1 or 0, (P= .66, χ2 test). The difference in proportion was 2.4% (95% CI: -8.5% to 13.4%). Since the upper boundary of the 95% CI crossed our non-inferiority margin of 10% (13.4%) we could not prove the non-inferiority of Racecadotril over Loperamide. Rebound constipation was more in the Loperamide arm compared to Racecadotril (17.3% vs 6.2%; P = .028) CONCLUSIONS: The non-inferiority of Racecadotril to Loperamide in acute radiation enteritis could not be demonstrated. However, Racecadotril can be the preferred drug of choice in acute radiation enteritis because Racecadotril does not affect bowel motility, achieved a high clinical success rate similar to that of Loperamide, and was associated with lesser side effects.


Subject(s)
Acute Radiation Syndrome , Enteritis , Thiorphan , Humans , Acute Disease , Acute Radiation Syndrome/drug therapy , Antidiarrheals/adverse effects , Diarrhea/drug therapy , Diarrhea/etiology , Double-Blind Method , Enteritis/etiology , Enteritis/chemically induced , Loperamide/adverse effects , Thiorphan/analogs & derivatives
2.
Fundam Clin Pharmacol ; 37(4): 753-768, 2023 Aug.
Article in English | MEDLINE | ID: mdl-36868872

ABSTRACT

The combined angiotensin receptor neprilysin inhibitor is a promising cardioprotective pharmacological agent. This study investigated the beneficial effects of thiorphan (TH)/irbesartan (IRB), in myocardial ischemia-reperfusion (IR) injury, compared to each of nitroglycerin and carvedilol. Male Wistar rats were divided into five groups (10 rats/group): Sham, untreated I/R, TH/IRB + IR (0.1/10 mg/kg), nitroglycerin + IR (0.2 mg/kg), and carvedilol + IR (10 mg/kg). Mean arterial blood pressure, cardiac functions and arrhythmia incidence, duration and score were assessed. Cardiac levels of creatine kinase-MB (CK-MB), oxidative stress, endothelin-1, ATP, Na+ /K+ ATPase pump activity and mitochondria complexes activities were measured. Histopathological examination, Bcl/Bax immunohistochemistry studies and electron microscopy examination of left ventricle were performed. TH/IRB preserved the cardiac functions and mitochondrial complexes activities, mitigated cardiac damage, reduced oxidative stress and arrhythmia severity, improved the histopathological changes and decreased cardiac apoptosis. TH/IRB showed a comparable effect to each of nitroglycerin and carvedilol in alleviating the IR injury consequences. TH/IRB showed significant preservation of mitochondrial complexes activity I and II compared to nitroglycerin. TH/IRB significantly increased LVdP/dtmax and decreased oxidative stress, cardiac damage and endothelin-1 along with increasing the ATP content, Na+ /K+ ATPase pump activity and mitochondrial complexes activity when compared to carvedilol. TH/IRB showed a cardioprotective effect in reducing IR injury that is comparable to each of nitroglycerin and carvedilol that could be explained in part by its ability to preserve mitochondrial function, increase ATP, decrease oxidative stress as well as endothelin 1.


Subject(s)
Myocardial Reperfusion Injury , Rats , Male , Animals , Myocardial Reperfusion Injury/pathology , Carvedilol/pharmacology , Irbesartan , Thiorphan/pharmacology , Nitrates , Neprilysin , Receptors, Angiotensin , Nitroglycerin , Endothelin-1 , Rats, Wistar , Cardiotonic Agents/pharmacology , Antihypertensive Agents/therapeutic use , Adenosine Triphosphatases , Adenosine Triphosphate
3.
Endocrinology ; 164(5)2023 03 13.
Article in English | MEDLINE | ID: mdl-36964914

ABSTRACT

The peptidase neprilysin modulates glucose homeostasis by cleaving and inactivating insulinotropic peptides, including some produced in the intestine such as glucagon-like peptide-1 (GLP-1). Under diabetic conditions, systemic or islet-selective inhibition of neprilysin enhances beta-cell function through GLP-1 receptor (GLP-1R) signaling. While neprilysin is expressed in intestine, its local contribution to modulation of beta-cell function remains unknown. We sought to determine whether acute selective pharmacological inhibition of intestinal neprilysin enhanced glucose-stimulated insulin secretion under physiological conditions, and whether this effect was mediated through GLP-1R. Lean chow-fed Glp1r+/+ and Glp1r-/- mice received a single oral low dose of the neprilysin inhibitor thiorphan or vehicle. To confirm selective intestinal neprilysin inhibition, neprilysin activity in plasma and intestine (ileum and colon) was assessed 40 minutes after thiorphan or vehicle administration. In a separate cohort of mice, an oral glucose tolerance test was performed 30 minutes after thiorphan or vehicle administration to assess glucose-stimulated insulin secretion. Systemic active GLP-1 levels were measured in plasma collected 10 minutes after glucose administration. In both Glp1r+/+ and Glp1r-/- mice, thiorphan inhibited neprilysin activity in ileum and colon without altering plasma neprilysin activity or active GLP-1 levels. Further, thiorphan significantly increased insulin secretion in Glp1r+/+ mice, whereas it did not change insulin secretion in Glp1r-/- mice. In conclusion, under physiological conditions, acute pharmacological inhibition of intestinal neprilysin increases glucose-stimulated insulin secretion in a GLP-1R-dependent manner. Since intestinal neprilysin modulates beta-cell function, strategies to inhibit its activity specifically in the intestine may improve beta-cell dysfunction in type 2 diabetes.


Subject(s)
Glucagon-Like Peptide-1 Receptor , Insulin Secretion , Neprilysin , Animals , Male , Mice , Diabetes Mellitus, Type 2 , Glucagon-Like Peptide 1 , Glucagon-Like Peptide-1 Receptor/metabolism , Glucose , Insulin/metabolism , Intestines , Mice, Inbred C57BL , Neprilysin/genetics , Neprilysin/metabolism , Thiorphan/pharmacology
4.
Fundam Clin Pharmacol ; 37(1): 31-43, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35830481

ABSTRACT

Mitochondria-mediated apoptosis plays a critical role in myocardial ischemia reperfusion (IR) injury and causes a negative impact on cardiac efficiency and function. The combined angiotensin receptor-neprilysin inhibitor (ARNI) is a promising cardioprotective pharmacological agent that could rescue the heart from IR injury. This study investigated the cardioprotective effect of thiorphan (TH) in combination with three different doses of irbesartan (IRB) on myocardial IR injury and detected the most effective dose combination. Male Wistar rats were used and divided into five groups (10 rats/group): (I) Sham, (II) ischemia-reperfusion I/R, (III) TH/IRB + IR (0.1/5 mg/kg), (IV) TH/IRB + IR (0.1/10 mg/kg), and (V) TH/IRB + IR (0.1/15 mg/kg) groups. Thiorphan and irbesartan were injected intraperitoneally 15 min before IR induction. Mean arterial blood pressure, left ventricular end diastolic pressure (LVEDP), left ventricular maximum rate of pressure (LVdp/dtmax ), and cardiac levels of creatine kinase-MB, malondialdehyde, superoxide dismutase, and endothelin-1 were measured. Cardiac mitochondria complexes activities, histopathological examination of myocardial tissues, immunohistochemistry studies for myocardial apoptosis (Bax and Bcl-2), and electron microscopy examination of left ventricle were performed. TH/IRB combination preserved cardiac functions and mitochondria complex activities and mitigated cardiac damage, oxidative stress, and apoptosis following IR. Also, there was an evident improvement in histopathological changes and electron microscopy examination of left ventricle compared with I/R group. TH/IRB in a dose of 0.1/10 mg/kg showed significant improvement compared with the other treated groups. Thiorphan/irbesartan improved cardiac functions following IR injury. This could be explained by the reported improvement of mitochondria complex activities and reduction of oxidative stress, endothelin-1, and apoptosis.


Subject(s)
Myocardial Reperfusion Injury , Rats , Animals , Male , Myocardial Reperfusion Injury/pathology , Irbesartan/pharmacology , Irbesartan/therapeutic use , Thiorphan/therapeutic use , Neprilysin , Receptors, Angiotensin/therapeutic use , Rats, Wistar , Endothelin-1/therapeutic use , Myocardium/pathology , Cardiotonic Agents/pharmacology
5.
Int J Mol Sci ; 23(24)2022 Dec 16.
Article in English | MEDLINE | ID: mdl-36555726

ABSTRACT

Antibiotic resistance has been becoming more and more critical due to bacteria's evolving hydrolysis enzymes. The NDM-1 enzyme could hydrolyze not only carbapenems but also most of ß-lactam's antibiotics and inhibitors. In fact, variant strains could impose a high impact on the resistance of bacteria producing NDM-1. Although previous studies showed the effect of some variants toward antibiotics and inhibitors binding, there has been no research systematically evaluating the effects of alternative one-point mutations on the hydrolysis capacity of NDM-1. This study aims to identify which mutants could increase or decrease the effectiveness of antibiotics and ß-lactamase inhibitors toward bacteria. Firstly, 35 different variants with a high probability of emergence based on the PAM-1 matrix were constructed and then docked with 5 ligands, namely d-captopril, l-captopril, thiorphan, imipenem, and meropenem. The selected complexes underwent molecular dynamics simulation and free energy binding estimation, with the results showing that the substitutions at residues 122 and 124 most influenced the binding ability of NDM-1 toward inhibitors and antibiotics. The H122R mutant decreases the binding ability between d-captopril and NDM-1 and diminishes the effectiveness of this antibiotic toward Enterobacteriaceae. However, the H122R mutant has a contrary impact on thiorphan, which should be tested in vitro and in vivo in further experiments.


Subject(s)
Carbapenems , beta-Lactamase Inhibitors , Carbapenems/pharmacology , Carbapenems/chemistry , beta-Lactamase Inhibitors/pharmacology , beta-Lactamase Inhibitors/chemistry , Point Mutation , Captopril , Thiorphan , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , beta-Lactamases/metabolism , Bacteria/metabolism , Microbial Sensitivity Tests
6.
J Vet Pharmacol Ther ; 45(5): 426-431, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35706330

ABSTRACT

This study was aimed to determine the pharmacokinetics of antisecretory-acting racecadotril, used in the treatment of diarrhea in humans and dogs, following oral administration in both neonatal calves with healthy and neonatal calves with infectious diarrhea. The study was carried out on a total of 24 Holstein calves (2-20 days), of which 6 were healthy and 18 were infectious diarrhea. Calves with infectious diarrhea were divided into 3 groups according to the infectious agent (Escherichia coli, Cryptosporidium parvum, and rotavirus/coronavirus). Racecadotril was administered orally at 2.5 mg/kg dose to calves. The plasma concentrations of racecadotril and its main active metabolite (thiorphan) were determined using HPLC-UV. The pharmacokinetic parameters were analyzed using the non-compartmental method. In healthy calves, the t1/2ʎz , Cmax , Tmax, and AUC0-12 of racecadotril were determined 4.70 h, 377 ng/ml, 0.75 h, and 1674 h × ng/ml, respectively. In the plasma of calves with infectious diarrhea, racecadotril and thiorphan were only detected at the sampling time from 0.25 to 1.5 h. As in calves with infectious diarrhea, thiorphan in plasma was only detected in healthy calves from 0.25 to 1.5 h. Racecadotril showed a large distribution volume, rapid elimination, and low metabolism to thiorphan in healthy calves.


Subject(s)
Cattle Diseases , Cryptosporidiosis , Cryptosporidium , Animals , Antidiarrheals/therapeutic use , Cattle , Cattle Diseases/drug therapy , Cryptosporidiosis/drug therapy , Diarrhea/drug therapy , Diarrhea/veterinary , Thiorphan/analogs & derivatives , Thiorphan/therapeutic use
8.
J Med Econ ; 25(1): 274-281, 2022.
Article in English | MEDLINE | ID: mdl-35125049

ABSTRACT

AIM: To evaluate the cost utility of adjunct racecadotril and oral rehydration solution (R + ORS) versus oral rehydration solution (ORS) alone for the treatment of diarrhoea in children under five years with acute watery diarrhoea in four low-middle income countries. METHOD: A cost utility model, previously developed and independently validated, has been adapted to Egypt, Morocco, Philippines and Vietnam. The model is a decision tree, cohort model programmed in Microsoft Excel. The model structure represents the country-specific clinical pathways. The target population is children under the age of five years presenting with symptoms of acute watery diarrhea to an outpatient clinic or general physician practice. A healthcare payer perspective has been analysed with the model parameterised with local data, where available. Most recent cost data has been used to inform the drug, outpatient and inpatient costs. Uncertainty has been explored with univariate deterministic sensitivity. RESULTS: According to the base case models, R + ORS is dominant (cost-saving, more effective) versus ORS alone in Egypt, Morocco, Philippines and Vietnam. The incremental cost-effectiveness ratios in each country fall in the southeast (cost-saving, more effective) quadrant and represent a cost savings of -304,152 EGP per QALY gain in Egypt; -6,561 MAD per QALY gain in Morocco; -428,612 PHP per QALY gain in Philippines and -113,985,734 VND per QALY gain in Vietnam. Univariate deterministic sensitivity analysis shows that the three most influential parameters across all country adaptations are the utility of children without diarrhea; the utility of inpatient children with diarrhea and the cost of one night of inpatient care. CONCLUSION: In keeping with similar findings in upper-middle and high-income countries, the cost utility of R + ORS versus ORS is favourable in low-middle income countries for the treatment of children under five with acute watery diarrhoea.


PLAIN LANGUAGE SUMMARYDecision-makers rely on cost utility models to inform decisions about whether to publicly fund treatments as part of Universal Health Care. In low-middle income countries, the capacity to prepare cost utility models may be limited and using existing validated models is a practical solution to assist decision making. This study uses a cost utility model developed and independently validated for the United Kingdom, and adapts it to Philippines, Egypt, Morocco and Vietnam. The model evaluates the clinical benefit and economic impact of using racecadotril in addition to rehydration solution to treat diarrhoea in children. The results show that racecadotril is cost-saving and improves the quality of life for children in Philippines, Egypt, Morocco and Vietnam.


Subject(s)
Antidiarrheals , Developing Countries , Diarrhea , Rehydration Solutions , Thiorphan , Antidiarrheals/economics , Antidiarrheals/therapeutic use , Child , Child, Preschool , Diarrhea/drug therapy , Diarrhea/economics , Egypt/epidemiology , Fluid Therapy , Humans , Infant , Morocco , Philippines , Rehydration Solutions/economics , Rehydration Solutions/therapeutic use , Thiorphan/analogs & derivatives , Thiorphan/economics , Thiorphan/therapeutic use , Vietnam
9.
Molecules ; 28(1)2022 Dec 22.
Article in English | MEDLINE | ID: mdl-36615293

ABSTRACT

Since natural substances are widely explored as epigenetic modulators of gene expression and epigenetic abnormalities are important causes of cancerogenesis, factors with pro-tumor activities subjected to epigenetic control, e.g., neutral endopeptidase (NEP, neprilysin), are promising anticancer targets for potential therapies acting via epigenetic regulation of gene expression. Alpha-ketoglutarate (AKG) is a naturally occurring co-substrate for enzymes involved in histone and DNA demethylation with suggested anti-cancer activity. Hence, we investigated a potential effect of AKG on the NEP expression in cells derived from various cancers (cervical, colon, osteosarcoma) and normal epithelial cells and osteoblasts. Moreover, the overall methylation status of histone H3 was explored to establish the molecular target of AKG activity. Additionally, it was investigated whether AKG in combination with thiorphan (NEP specific inhibitor) exhibited enhanced anticancer activity. The results revealed that AKG downregulated the expression of NEP at the protein level only in highly aggressive osteosarcoma HOS cells (flow cytometry and fluorometric assays), and this protease was found to be involved in AKG-induced growth inhibition in osteosarcoma cells (siRNA NEP silencing, BrdU assay, flow cytometry). Unexpectedly, AKG-induced hypermethylation of H3K27 in HOS cells, which was partially dependent on EZH2 activity. However, this effect was not implicated in the AKG-induced NEP downregulation (flow cytometry). Finally, the combined treatment with AKG and thiorphan was shown to significantly enhance the growth inhibitory potential of each one towards HOS cells (BrdU assay). These preliminary studies have shown for the first time that the downregulation of NEP expression is a promising target in therapies of NEP-implicating HOS cells. Moreover, this therapeutic goal can be achieved via AKG-induced downregulation of NEP and synergistic activity of AKG with thiorphan, i.e., a NEP specific inhibitor. Furthermore, this study has reported for the first time that exogenous AKG can influence the activity of histone methyltransferase, EZH2. However, this issue needs further investigation to elucidate the mechanisms of this phenomenon.


Subject(s)
Osteosarcoma , Thiorphan , Humans , Thiorphan/metabolism , Neprilysin , Ketoglutaric Acids/pharmacology , Epigenesis, Genetic , Bromodeoxyuridine , Histones/metabolism , Osteosarcoma/drug therapy , Osteosarcoma/genetics
10.
Int J Mol Sci ; 22(15)2021 Jul 30.
Article in English | MEDLINE | ID: mdl-34360996

ABSTRACT

ß-Casomorphin-7 (BCM) is a degradation product of ß-casein, a milk component, and has been suggested to affect the immune system. However, its effect on mucosal immunity, especially anti-tumor immunity, in cancer-bearing individuals is not clear. We investigated the effects of BCM on lymphocytes using an in vitro system comprising mouse splenocytes, a mouse colorectal carcinogenesis model, and a mouse orthotopic colorectal cancer model. Treatment of mouse splenocytes with BCM in vitro reduced numbers of cluster of differentiation (CD) 20+ B cells, CD4+ T cells, and regulatory T cells (Tregs), and increased CD8+ T cells. Administration of BCM and the CD10 inhibitor thiorphan (TOP) to mice resulted in similar alterations in the lymphocyte subsets in the spleen and intestinal mucosa. BCM was degraded in a concentration- and time-dependent manner by the neutral endopeptidase CD10, and the formed BCM degradation product did not affect the lymphocyte counts. Furthermore, degradation was completely suppressed by TOP. In the azoxymethane mouse colorectal carcinogenesis model, the incidence of aberrant crypt foci, adenoma, and adenocarcinoma was reduced by co-treatment with BCM and TOP. Furthermore, when CT26 mouse colon cancer cells were inoculated into the cecum of syngeneic BALB/c mice and concurrently treated with BCM and TOP, infiltration of CD8+ T cells was promoted, and tumor growth and liver metastasis were suppressed. These results suggest that by suppressing the BCM degradation system, the anti-tumor effect of BCM is enhanced and it can suppress the development and progression of colorectal cancer.


Subject(s)
Adenocarcinoma/drug therapy , Colorectal Neoplasms/drug therapy , Endorphins/therapeutic use , Lymphocytes/immunology , Peptide Fragments/therapeutic use , Adenocarcinoma/immunology , Adenocarcinoma/pathology , Animals , Cell Line, Tumor , Cells, Cultured , Colorectal Neoplasms/immunology , Colorectal Neoplasms/pathology , Endorphins/pharmacology , Intestinal Mucosa/cytology , Intestinal Mucosa/immunology , Lymphocytes/drug effects , Male , Mice , Mice, Inbred BALB C , Neoplasm Metastasis , Peptide Fragments/pharmacology , Protease Inhibitors/pharmacology , Spleen/cytology , Spleen/immunology , Thiorphan/pharmacology
11.
AAPS PharmSciTech ; 22(1): 15, 2021 Jan 03.
Article in English | MEDLINE | ID: mdl-33389269

ABSTRACT

The present study endeavored to develop orodispersible films (ODFs) containing 30 mg racecadotril for pediatric use, which focuses on improving the compliance of pediatric patients and reducing risk of choking. The challenge of this study is to prepare high drug loading ODFs with successful mechanical and physicochemical properties. Compatibilities between drug and different polymers (hydroxypropyl methylcellulose, HPMC; polyvinyl alcohol, PVA; low-substituted hydroxypropyl cellulose, L-HPC; pullulan, PU) were investigated to select stable and safe film-forming polymers. Afterwards, the study explored the maximum amount of racecadotril incorporated into PVA films and PU films. Subsequently, disintegrant (Lycoat RS720, 4-10%, w/w) and plasticizers (glycerol, 2-6%, w/w) were investigated to reduce disintegration time of PVA films and enhance the flexibility of PU films, respectively. Formulation characteristics (appearance, tensile strength, percent elongation, disintegration time, drug content, weight, thickness, pH value, moisture content, moisture uptake, and Q5min) of prepared ODFs were examined to obtain the optimal compositions of racecadotril ODFs. Differential scanning calorimetry (DSC) study, powder X-ray diffraction (XRD) study, Fourier transform infrared (FTIR) study, comparative in vitro dissolution study, and pharmacokinetic study in Beagle dogs of optimized racecadotril ODFs were then conducted. Eventually, ODFs containing 50% racecadotril, 38% PVA, 7% Lycoat RS720, 2% sucralose, 2% apricot, and 1% titanium dioxide could achieve desirable mechanical properties, disintegrating within a few seconds and releasing more than 85% drug within 5 min in four dissolution media. An in vivo study showed optimized racecadotril ODF and Hidrasec were bioequivalent in Beagle dogs. In summary, ODFs containing 30 mg racecadotril were successfully prepared by solvent casting method, and it was suitable for the administration to the pediatric patients.


Subject(s)
Antidiarrheals/pharmacology , Thiorphan/analogs & derivatives , Acrylic Resins/chemistry , Administration, Oral , Antidiarrheals/administration & dosage , Calorimetry, Differential Scanning , Cellulose/analogs & derivatives , Child , Dosage Forms , Excipients/chemistry , Humans , Hypromellose Derivatives/chemistry , In Vitro Techniques , Pediatrics , Polyvinyl Alcohol/chemistry , Powders , Solubility , Solvents/chemistry , Thiorphan/administration & dosage , Thiorphan/pharmacology , X-Ray Diffraction
12.
Mol Pharmacol ; 98(4): 454-461, 2020 10.
Article in English | MEDLINE | ID: mdl-32606204

ABSTRACT

Endogenous opioid peptides in the amygdala regulate many of our behaviors and emotional responses. In particular, the endogenous opioid enkephalin plays a significant role in regulating amygdala activity, but its action is strongly limited by peptidases, which degrade enkephalin into inactive fragments. Inhibiting peptidases may be an attractive method to enhance endogenous opioid signaling; however, we do not know which specific peptidase(s) to target. Using inhibition of glutamate release onto the intercalated cells of the amygdala as an assay for enkephalin activity, we applied specific peptidase inhibitors to determine which peptidase(s) regulate enkephalin signaling in this region. Thiorphan (10 µM), captopril (1 µM), or bestatin (10 µM) were used to inhibit the activity of neprilysin, angiotensin-converting enzyme, or aminopeptidase N, respectively. In rat brain slices containing the intercalated cells, we found that inhibition of glutamate release by a submaximal concentration of enkephalin was doubled by application of all three peptidase inhibitors combined. Then, we tested inhibitors individually and found that inhibition of neprilysin alone could enhance enkephalin responses to the same extent as inhibitors of all three peptidases combined. This indicates neprilysin is the predominant peptidase responsible for degrading enkephalins in the intercalated cells of the amygdala. This differs from the striatum, locus coeruleus, and spinal cord, where multiple peptidases metabolize enkephalin. These data highlight the importance of knowing which specific peptidase(s) control opioid actions in the relevant neural circuit and how they change in disease states to allow rational choices of drugs targeting the specific peptidase of interest. SIGNIFICANCE STATEMENT: Endogenous opioids modulate many of our emotional and behavioral responses. In the amygdala, they modulate our pain, fear, and addictive behaviors. Their actions are terminated when they are catabolized into inactive fragments by at least three different peptidases. In this study, we found that neprilysin selectively controls endogenous opioid concentrations at synapses in the intercalated cells of the amygdala. This peptidase may be a target for regulation of endogenous opioid modulation of amygdala-mediated emotional and behavioral responses.


Subject(s)
Amygdala/metabolism , Enkephalins/metabolism , Neprilysin/metabolism , Protease Inhibitors/pharmacology , Animals , Captopril/pharmacology , Electrical Synapses/drug effects , Electrical Synapses/metabolism , Glutamic Acid/metabolism , Leucine/analogs & derivatives , Leucine/pharmacology , Male , Neprilysin/antagonists & inhibitors , Proteolysis/drug effects , Rats , Rats, Sprague-Dawley , Signal Transduction/drug effects , Thiorphan/pharmacology
13.
Eur J Pharmacol ; 882: 173295, 2020 Sep 05.
Article in English | MEDLINE | ID: mdl-32593664

ABSTRACT

Ventricular arrhythmias are considered as a major risk of sudden cardiac death. This study was designed to investigate the potential effects of angiotensin receptor neprilysin inhibitor; thiorphan/irbesartan (TH/IRB) combination therapy on myocardial ischemic-reperfusion (I/R)-induced arrhythmia. Fifty male Wistar rats were divided into 5 groups; (I, II): Sham, I/R both received DMSO intraperitoneally before the procedure. (III, IV, V): TH/IRB + IR (0.1/5 mg/kg, 0.1/10 mg/kg and 0.1/15 mg/kg). The drugs were injected intraperitoneally 15 min before I/R induction. Electrocardiograms changes, mean arterial blood pressure, incidence of ventricular tachycardia (VT), incidence of ventricular fibrillation (VF) and arrhythmia score were assessed. Cardiac levels of creatinine kinase-MB (CK-MB), Malondialdehyde (MDA), superoxide dismutase (SOD), endothelin-1 (ET-1), ATP content, and Na+/K+-ATPase pump activity were measured. TH (0.1 mg/kg) in combination with IRB (5, 10 and 15 mg/kg) produced significant decrease in QTc interval duration, ST height, incidence of VT and VF, duration of VT + VF, and arrhythmia score compared to I/R group. All treated groups showed significant decrease in the cardiac levels of: CK-MB, MDA and ET-1 and significant increase in SOD, ATP content, and Na+/K+-ATPase pump activity compared to I/R. TH/IRB + IR (0.1/10 mg/kg) group produced significant decrease in CK-MB, MDA and ET-1 and a significant increase in SOD, ATP content, and Na+/K+-ATPase pump activity compared to other treated groups. In conclusion, angiotensin receptor neprilysin inhibitor (thiorphan/irbesartan) decreased arrhythmia score and decreased cardiac damage. These could be explained in part by its ability to decrease oxidative stress and ET-1, increase ATP, and Na+/K+-ATPase pump activity in this rat model of I/R-induced arrhythmia.


Subject(s)
Angiotensin Receptor Antagonists/therapeutic use , Irbesartan/therapeutic use , Myocardial Reperfusion Injury/drug therapy , Neprilysin/antagonists & inhibitors , Tachycardia, Ventricular/drug therapy , Thiorphan/therapeutic use , Adenosine Triphosphate/metabolism , Animals , Irbesartan/pharmacology , Male , Malondialdehyde/metabolism , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/physiopathology , Myocardium/metabolism , Rats, Wistar , Receptors, Angiotensin/physiology , Sodium-Potassium-Exchanging ATPase/metabolism , Superoxide Dismutase/metabolism , Tachycardia, Ventricular/metabolism , Tachycardia, Ventricular/physiopathology , Thiorphan/pharmacology
14.
Int J Clin Pharmacol Ther ; 58(7): 408-414, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32352368

ABSTRACT

OBJECTIVE: The objective of this study was to use LC-MS/MS to compare the pharmacodynamic properties and bioequivalence of two 200-mg formulations of racecadotril: suspension formulation (test) and granule formulation (reference) in healthy Chinese subjects. MATERIALS AND METHODS: A single-dose, randomized, two-period crossover study was conducted in fasted healthy Chinese subjects, who received a single oral dose of the test or reference formulation, followed by a 7-day washout period and administration of the alternate formulation. RESULTS: The rapid and highly sensitive LC-MS/MS method exhibited a reasonable linearity range (2.324 - 952.000 ng/mL) and high sensitivity (LLOQ of 2.324 ng/mL). The within- and between-run precision, accuracy, and stability results were within the acceptable limits, and no matrix effect was observed. The 90% CI of the ratio of geometric means for AUC0-t, AUC0-∞, and Cmax were 88.1 - 102.3%, 87.9 - 101.5% and 99.5 - 113%, respectively, which met the regulatory criteria for bioequivalence. CONCLUSION: The method is suitable for quantification of thiorphan in human plasma. In addition, the results indicated that the test and reference formulations were bioequivalent in terms of both rate and extent of absorption.


Subject(s)
Protease Inhibitors , Tandem Mass Spectrometry , Thiorphan/analogs & derivatives , Area Under Curve , Biological Availability , Chromatography, Liquid , Cross-Over Studies , Humans , Protease Inhibitors/blood , Tablets , Therapeutic Equivalency , Thiorphan/blood
15.
J Pediatr Gastroenterol Nutr ; 70(2): 162-164, 2020 02.
Article in English | MEDLINE | ID: mdl-31978009

ABSTRACT

Acute diarrhoea is a leading cause of morbidity and mortality in the paediatric population. Racecadotril is an antisecretory drug recommended as an adjuvant antidiarrhoeal treatment.In the small bowel, the enzyme neutral endopeptidase (NEP) inhibits the action of enkephalins, which prevent water and electrolyte hypersecretion. By inhibiting NEP, racecadotril allows enkephalins to exhibit their antisecretory effects. Consequently, racecadotril reduces the secretion of water and electrolytes in the small intestine, without having an effect on intestinal motility. No serious adverse events related to racecadotril have been reported.Racecadotril has proven its efficacy as an adjuvant antidiarrhoeal drug with a good safety profile. Its addition to oral rehydration solution (ORS) appears clinically beneficial and potentially leads to health care savings.


Subject(s)
Gastrointestinal Diseases , Pharmaceutical Preparations , Antidiarrheals/therapeutic use , Child , Diarrhea/drug therapy , Gastrointestinal Diseases/drug therapy , Humans , Thiorphan/analogs & derivatives , Thiorphan/therapeutic use
16.
Cochrane Database Syst Rev ; 12: CD009359, 2019 12 19.
Article in English | MEDLINE | ID: mdl-31858591

ABSTRACT

BACKGROUND: Acute diarrhoea is a leading cause of death for children under five years of age. Most deaths are caused by excessive fluid and electrolyte losses. Racecadotril is an anti-secretory drug that has been used for acute diarrhoea in children as an adjunct to oral rehydration therapy. OBJECTIVES: To assess the efficacy and safety of racecadotril for treating acute diarrhoea in children under five years of age. SEARCH METHODS: We searched the Cochrane Infectious Diseases Group Specialized Register; the Cochrane Central Register of Controlled Trials (CENTRAL, published in the Cochrane Library Issue 3, March 2019); MEDLINE; Embase; LILACS; ClinicalTrials.gov; and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP), up to 4 March 2019, for clinical trials regardless of publication language or status. SELECTION CRITERIA: Randomized controlled trials (RCTs) that compared racecadotril to placebo or no intervention in addition to standard care (oral rehydration therapy) in children under five with acute diarrhoea. The primary outcomes were failure of oral rehydration, duration of diarrhoea, and number of stools. The secondary outcomes were stool output, length of the hospital stay, and adverse events. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial eligibility, extracted the data and assessed risk of bias. We presented dichotomous data with risk ratios (RR) and continuous data with mean difference (MD) or standardized mean difference (SMD). Where appropriate, we combined trials with meta-analysis and used a random-effects model if there was significant heterogeneity (I² ≥ 50%). We assessed the certainty of the evidence using the GRADE approach. MAIN RESULTS: Seven RCTs with a total of 1140 participants met the inclusion criteria. The trials were carried out on children aged three months to five years, in outpatient and inpatient facilities from France, Spain, Peru, India, Kenya, and Ecuador. The efficacy and safety of racecadotril were compared to placebo or no treatment. Racecadotril may reduce the risk of rehydration failure (RR 0.41, 95% CI 0.13 to 1.23; 2 RCTs, 192 participants; low-certainty evidence). Data on duration of diarrhoea, number of stools in the first 48 hours are insufficient to reach a conclusion; stool output in the first 48 hours appears to be lower in the two trials measuring this, although the data is not combinable. Length of hospital stay was similar in two studies measuring this, and overall there was no evidence that racecadotril increased overall rate of adverse events (RR 0.90, 95% CI 0.66 to 1.22; 5 RCTs, 688 participants; low-certainty evidence). Most adverse events in the racecadotril group were mild or moderate. AUTHORS' CONCLUSIONS: Racecadotril seems to be a safe drug but has little benefit in improving acute diarrhoea in children under five years of age. Current evidence does not support routine use of racecadotril in management of acute diarrhoea in children under five outside of the context of placebo controlled RCTs. 18 December 2019 Up to date All studies incorporated from most recent search All studies identified during the most recent search (4 Mar, 2019) have been incorporated in the review, and no ongoing studies identified.


Subject(s)
Diarrhea/drug therapy , Thiorphan/analogs & derivatives , Child, Preschool , Fluid Therapy , Humans , Infant , Length of Stay , Randomized Controlled Trials as Topic , Thiorphan/therapeutic use , Treatment Outcome
17.
Pharmacol Rep ; 71(5): 958-967, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31470292

ABSTRACT

BACKGROUND: Neprilysin inhibitors (NEPi) are assisting the renin-angiotensin system (RAS) inhibitors in halting diabetic cardiomyopathy (DCM). Away from conventional tactic, a recent report revealed the renoprotective potential of NEPi and angiotensin-converting enzyme (ACE2) activator combination therapy against diabetic nephropathy. However, this combination so far not evaluated against DCM, thus the present investigation aiming the same. METHODS: Streptozotocin-induced (55 mg/kg, ip) type 1 diabetic (T1D) male Wistar rats were treated with either monotherapy of thiorphan (0.1 mg/kg/day, po) or diminazene aceturate (5 mg/kg/day, po), or their combination therapy, for four weeks. After hemodynamic measurements, all the rats' heart and plasma were collected for biochemistry, ELISA, histopathology, and immunoblotting. RESULTS: Metabolic perturbations and failing cardiac functions associated with diabetes were markedly attenuated by combination therapy. Besides, unfavourable alterations in RAS and natriuretic peptides system (NPS) were corrected by combination therapy. Interestingly, combination therapy significantly increased plasma and heart cGMP levels compared to T1D and monotherapy receiving rats. Moreover, rats receiving combination therapy exhibited significant inhibition of activated NF-κB, TGF-ß and apoptotic signalling, and a notable reduction in cardiac fibrosis when compared to T1D rats. Expressions of posttranslational histone modifications markers; H3K4Me2 and its methyltransferases (SET7/9 and RBBP5) were significantly enhanced in T1D hearts, which were significantly reduced by combination therapy. CONCLUSIONS: The NEPi and ACE2 activator combination therapy effectively prevented DCM by normalising RAS and NPS activities, increasing cGMP, inhibiting inflammatory, pro-fibrotic and apoptotic signalling, and reversing H3K4Me2 and its methyl transferases expressions.


Subject(s)
Diabetes Mellitus, Experimental/drug therapy , Diabetes Mellitus, Type 1/drug therapy , Diabetic Cardiomyopathies/prevention & control , Neprilysin/antagonists & inhibitors , Peptidyl-Dipeptidase A/metabolism , Angiotensin-Converting Enzyme 2 , Animals , Diabetes Mellitus, Experimental/metabolism , Diabetes Mellitus, Type 1/metabolism , Diabetic Cardiomyopathies/metabolism , Diminazene/administration & dosage , Diminazene/analogs & derivatives , Diminazene/therapeutic use , Drug Therapy, Combination , Enzyme Activation/drug effects , Male , Rats, Wistar , Streptozocin , Thiorphan/administration & dosage , Thiorphan/therapeutic use
18.
Acta Crystallogr F Struct Biol Commun ; 75(Pt 6): 405-411, 2019 Jun 01.
Article in English | MEDLINE | ID: mdl-31204686

ABSTRACT

Neutral endopeptidase (neprilysin; NEP) is a proteinase that cleaves a wide variety of peptides and has been implicated in Alzheimer's disease, cardiovascular conditions, arthritis and other inflammatory diseases. The structure of the soluble extracellular domain (residues 55-750) of rabbit neprilysin was solved both in its native form at 2.1 Šresolution, and bound to the inhibitors phosphoramidon and thiorphan at 2.8 and 3.0 Šresolution, respectively. Consistent with the extracellular domain of human neprilysin, the structure reveals a large central cavity which contains the active site and the location for inhibitor binding.


Subject(s)
Glycopeptides/metabolism , Models, Molecular , Neprilysin/chemistry , Neprilysin/metabolism , Protease Inhibitors/metabolism , Thiorphan/metabolism , Amino Acid Sequence , Animals , Crystallography, X-Ray , Glycopeptides/chemistry , Protease Inhibitors/chemistry , Protein Conformation , Rabbits , Substrate Specificity , Thiorphan/chemistry
19.
Molecules ; 24(12)2019 Jun 18.
Article in English | MEDLINE | ID: mdl-31216628

ABSTRACT

A stereoselective synthetic strategy for the preparation of trifluoromethylamine mimics of retro-thiorphan, involving a diastereoselective, metal-free catalytic step, has been studied in batch and afforded the target molecule in good yields and high diastereoselectivity. A crucial point of the synthetic sequence was the catalytic reduction of a fluorinated enamine with trichlorosilane as reducing agent in the presence of a chiral Lewis base. The absolute configuration of the key intermediate was unambiguously assigned by X-ray analysis. The synthesis was also investigated exploiting continuous flow reactions; that is, an advanced intermediate of the target molecule was synthesized in only two in-flow synthetic modules, avoiding isolation and purifications of intermediates, leading to the isolation of the target chiral fluorinated amine in up to an 87:13 diastereoisomeric ratio.


Subject(s)
Thiorphan/analogs & derivatives , Catalysis , Halogenation , Models, Molecular , Molecular Structure , Oxidation-Reduction , Stereoisomerism , Thiorphan/chemistry , Thiorphan/metabolism
20.
Chem Biol Interact ; 307: 105-115, 2019 Jul 01.
Article in English | MEDLINE | ID: mdl-31054283

ABSTRACT

Neutral endopeptidase (NEP) is an enzyme implicated in development of different tumors, e.g. colorectal cancer (CRC). In this study, the anti-cancer effects of NEP inhibitors, thiorphan (synthetic compound) and sialorphin (naturally occurring pentapeptide) on CRC cells were investigated. Moreover, we synthesized some derivatives of sialorphin (alanine scan analogues: AHNPR, QANPR, QHAPR, QHNAR; N-acetylated sialorphin; C-amidated sialorphin, and C-amidated alanine scan analogues) to examine the biological activity of these inhibitors on CRC cells. The cytotoxic activity of the NEP inhibitors against CRC cell lines (SW620 and LS180) and normal human fibroblasts (HSF) was evaluated. Additionally, the influence of NEP inhibitors on proliferation, cell cycle progression, induction of apoptosis, and the level of phosphorylation of MAP kinases and mTORC1 signaling pathway proteins in CRC cells were examined. The NEP inhibitors were non-cytotoxic to HSF cells; however, most of them slightly decreased the viability and inhibited proliferation of CRC cells. The N-acetylation or C-amidation of sialorphin or its alanine scan analogues resulted in decreased or abolished anti-proliferative activity of the NEP inhibitors towards the CRC cells. Additionally, thiorphan and sialorphin enhanced the anti-proliferative activity of other CRC-cell growth inhibitors (atrial natriuretic peptide-ANP and melphalan-MEL). The mechanisms involved in the anti-proliferative effects of the tested inhibitors were mediated via NEP and associated with induction of cell cycle arrest in the G0/G1 phase, increased activity of ERK1/2, and a reduced level of phosphorylation of mTOR (Ser2448), 4E-BP1, and p70S6K. However, the NEP inhibitors did not induce apoptosis in the CRC cells. These results have indicated that thiorphan and sialorphin or its derivatives AHNPR, QANPR, QHAPR, and QHNAR have the potential to be used as agents in treatment of patients with CRC.


Subject(s)
Cell Proliferation/drug effects , Endopeptidases/metabolism , Peptides/pharmacology , Protease Inhibitors/pharmacology , Thiorphan/pharmacology , Adaptor Proteins, Signal Transducing/metabolism , Apoptosis/drug effects , Cell Cycle Proteins , Cell Line, Tumor , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Endopeptidases/chemistry , Endopeptidases/genetics , G1 Phase Cell Cycle Checkpoints/drug effects , Humans , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/metabolism , Peptides/chemical synthesis , Peptides/chemistry , Phosphoproteins/metabolism , Phosphorylation/drug effects , Protease Inhibitors/chemistry , RNA Interference , RNA, Small Interfering/metabolism , TOR Serine-Threonine Kinases/metabolism , Thiorphan/chemistry
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