Involvement of Histamine 2 Receptor in Alpha 1 Adrenoceptor Mediated Cardiac Hypertrophy and Oxidative Stress in H9c2 Cardio Myoblasts.

Despite the involvement of ɑ1adrenergic (ɑ1AR) and Histamine 2 receptors (H2R) in cardiac hypertrophy (CH), their relationship is yet to be studied. Our study investigated interrelationship between them using in vitro CH model. H9c2 cardiomyoblasts were exposed to phenylephrine (ɑ1AR agonist-50 µM) in the presence, the absence of famotidine (H2R antagonist-10 µM) and BAY 11-7082 (NF-kB inhibitor-10 µM). The impact of ɑ1AR stimulation on H2R expression and oxidative stress was assessed. Hypertrophic indices were assessed from activities of enzymatic mediators of cardiac hypertrophy, total protein content, BNP levels and cell volume. Additionally, the inverse agonistic property of famotidine and NFkB activity was also studied. ɑ1AR-induced H2R expression, oxidative stress and hypertrophic indices were significantly abolished by famotidine and pharmacological inhibitor of NFkB. Increase in constitutive activity of H2R was noticed correlating with increased receptor population. These results suggest involvement of NFkB-mediated upregulation of H2R in ɑ1AR-mediated CH.

Beta 1 adrenoceptor blockade promotes angiogenesis in hypertrophied myocardium of transverse aortic constricted mice.

Left ventricular hypertrophy (LVH) is an adaptive structural remodelling consequent to uncontrolled blood pressure. Impaired angiogenesis plays a vital role in transiting LVH into cardiac failure. Catecholamines modulate myocardial function through beta adrenoceptors, and their blockers (ß-AR) reduce cardiovascular morbidity and mortality by decelerating the LVH progression. Nonetheless, the effect of ß-AR blockers on myocardial vascular bed remains largely obscure. Hence, this study is focussed on analysing the possible outcomes of ß-AR blockers on myocardial vascular remodelling using a surgically induced LVH mice model. Transverse aortic constricted mice and sham-operated mice were administered with metoprolol at a dose of 30 mg/kg/d for 60 days and myocardial vascular endothelial growth factor (VEGF) alpha levels, GSH/GSSG ratio, myocardial protein carbonyl content, hypertrophy index and global myocardial function, trans-aortic fluid dynamics and expression pattern of angiopoietin-1 and VEGF alpha were assessed. These findings were further confirmed by histochemical analysis for myocardial capillary density, perivascular fibrosis ratio and intimal thickening. Sub- chronic ß-AR blockade reduced the oxidative stress, hypertrophic index, intimal thickening and perivascular fibrosis ratio. A marked increase in myocardial VEGF, angiopoietin 1, global myocardial function and myocardial capillary density was also observed. There was a reduction in the LVH and upregulation of myocardial angiogenesis concluding that ß-AR blockers prevent adverse vascular remodelling which might underlie its concealed mechanism of action.

Association of histamine with hypertension-induced cardiac remodeling and reduction of hypertrophy with the histamine-2-receptor antagonist famotidine compared with the beta-blocker metoprolol.

The association of histamine with adverse cardiac remodeling in chronic pressure overload has not received much attention. A pilot study in spontaneously hypertensive rats (SHRs) indicated a reduction of left ventricular hypertrophy (LVH) with a histamine-2-receptor (H2R) antagonist (famotidine). This finding prompted a detailed investigation of temporal variation in myocardial histamine and H2R expression and the cardiovascular response to H2R antagonism compared with that of the conventional beta-blocker metoprolol. Reduction of LVH is known to reduce the risk of adverse cardiovascular events. The myocardial histamine content and H2R expression increased with age in SHRs but not in normotensive Wistar rats. The cardiovascular response to famotidine (30 mg kg-1) was compared with that of metoprolol (50 mg kg-1) in 6-month-old male SHRs treated for 60 days. The decrease in diastolic blood pressure and improvement in cardiac function induced by famotidine and metoprolol were comparable. Both treatments caused the regression of LVH as assessed from the hypertrophy index, histomorphometry, B type natriuretic peptide (BNP), pro-collagen 1, and hydroxyproline levels. Calcineurin-A expression (marker of pathological remodeling) decreased, and Peroxiredoxin-3 expression (mitochondrial antioxidant) increased in response to the treatments. The myocardial histamine levels decreased with the treatments. The age-dependent increase in myocardial histamine and H2R in the SHRs signifies their association with progressive cardiac remodeling. The regression of LVH and improvement in cardiac function by famotidine further demonstrates the role of histamine in cardiac remodeling. Hypertrophy of cultured cardiac cells upon exposure to histamine and the H2R agonist amthamine substantiates the role of histamine in cardiac remodeling. The cardiovascular response to famotidine is comparable to that of metoprolol, suggesting repurposing of H2R antagonists for the management of hypertensive heart disease.

Crocin attenuates cyclophosphamide induced testicular toxicity by preserving glutathione redox system.

Chemotherapy induced testicular toxicity is an emerging reason for azoospermia and impotency in males. Cyclophosphamide (CP) is a widely used chemotherapeutic agent to manage neoplastic and non-neoplastic autoimmune diseases. Testicular toxicity along with bladder and hepatotoxicity are its widely reported adverse effects. Crocin (CR) is the digentiobiosyl ester of crocetin, found in the fruits of gardenia (Gardenia jasminoides E.) and dried stigmas of saffron (Crocus sativus L.) possess antioxidant, anti-depressant, anti-tumor and aphrodisiac properties. In the light of these reports, the present study aimed to investigate protective effect of CR administration (10 mg/kg and 20 mg/kg per day for eight weeks) on CP induced (15 mg/kg per week for eight weeks) testicular toxicity in male Sprague dawley rats by analysing the Glutathione redox cycle, Sperm quality, spermatogenic and steroidogenesis hormonal axis, caspase 3 activity and histological investigations. Administration of CR preserved the glutathione redox cycle, sperm quality, hormonal mediators associated with sperm production. It also decreased testicular apoptosis as evident from the reduction of caspase 3 activity. These biochemical findings were well reflected on the histo-pathological investigation. Conclusively, the results of this study indicate that administration of CR can dose dependently attenuate the toxic effects of CP on testis.

Histamine 2 receptor antagonism elicits protection against doxorubicin-induced cardiotoxicity in rodent model.

Doxorubicin (DOX), an anthracycline-based antibiotic, is regularly used in the management of carcinomas, and haematological malignancies have been downplayed in chemotherapy because of its ability to induce dilated cardiomyopathy (DCM). Dexrazoxane is approved to combat the cardiotoxicity, but limited by its adverse effects. Redox imbalance and reactive oxygen species generation plays major role in DOX-induced cardiotoxicity. Histamine, known to mediate various cardiovascular effects, but nevertheless the role of histamine or its receptors in DOX-induced DCM is remained obscure. Hence, this study is aimed to examine the effect of Famotidine (FAM), a H2 receptor antagonist on DOX-induced DCM in Wistar rats. Myocardial antioxidant status, stress and apoptosis markers, myocardial morphology and function were evaluated as the end points. Treatment with FAM has alleviated DOX doxorubicin-induced cardiotoxicity by reducing oxidative and nitrosative stress evident from lipid peroxidation and total nitrate-to-nitrite ratio, and enhanced the activity of super oxide dismutase. Cardiac stress markers like LDH and Na+-K+ATPase activities as well as CK-MB and Cardiac troponin levels were reduced by FAM treatment. It also normalised the myocardial function as assessed by 2D echocardiography and myocardial index. Treatment imparted anti-apoptotic effect as evident from decrease in myocardial caspase 3 and 9 activity and cleaved PARP expression. Effect of FAM is found to be comparable to the standard ACE inhibitor Captopril (CAP). The results from this study collectively suggest H2 receptor antagonism as a novel therapeutic strategy to impart biochemical, structural and functional improvement indicating its cardio-protective activity.

Pharmacokinetics and brain uptake study of novel AMPA receptor antagonist perampanel in SD rats using a validated UHPLC-QTOF-MS method.

Perampanel (PER) is a novel AMPA receptor antagonist for antiepileptic therapy and is prospective for the treatment of other neurological disorders. A highly sensitive and rapid UHPLC-QTOF-MS method was developed for the quantification of PER in plasma/brain homogenate of SD rat with alogliptin as an internal standard (IS). Chromatographic separation was carried out on an Acquity UPLC HSS Cyano column (100mm×2.1mm, 1.8µm) using gradient mobile phase consisting of 0.1% formic acid and acetonitrile at a flow rate of 0. 4mL/min. Sample preparation was carried out by a simple protein precipitation method. The mass spectrometric analysis of target ions at [M+H]+m/z 350.1288 for PER and m/z 340.1779 for IS was monitored with extracted ion chromatography. The developed analytical method meets the US-FDA and EMA bioanalytical guidelines and was found to be precise, accurate, selective and rugged. It exhibited good sensitivity (0.4ng/mL) and linearity over a range of 0.4-400ng/mL in both the bio-matrices. The method was successfully applied to pharmacokinetics and brain uptake study of PER after oral administration to SD rats. The study results showed PER has penetrated the blood-brain barrier, brain to plasma ratio (Kp) was found to be 0.62±0.05 and its rapidly eliminated from the brain.

A validated UHPLC-QTOF-MS method for quantification of metformin and teneligliptin in rat plasma: Application to pharmacokinetic interaction study.

In this study a sensitive UHPLC-QTOF-MS method was developed and validated for the quantitation of the metformin (MET) and teneligliptin (TEN) in rat plasma using dapagliflozin as an internal standard (IS). Chromatographic separation were carried out on a Acquity UPLC HSS Cyano column (100mm x 2.1mm, 1.8µm) using gradient mobile phase system consisting of 0.1% formic acid and acetonitrile at a flow rate of 0.4mL/min, within a run time of 6min. Protein precipitation method was used as sample preparation approach. Detection of target ions [M+H]+ at m/z 130.1085 for MET, m/z 427.2277 for TEN and m/z 409.1623 for IS was performed at positive ion electrospray ionization mode. Linearity was assessed in the range of 0.98-1000ng/mL for both MET and TEN. The developed assay was validated as per US-FDA and EMA bioanalytical guidelines and successfully applied to pharmacokinetic interaction study in SD rats. A 1.1 fold increment in the AUC levels of MET and TEN was observed when co-administered together in rats.

LC-ESI-MS/MS evaluation of forced degradation behaviour of silodosin: In vitro anti cancer activity evaluation of silodosin and major degradation products.

Silodosin (SLD) a novel α1-adrenoceptor antagonist was subjected to forced degradation involving hydrolysis (acidic, alkaline and neutral), oxidative, photolysis and thermal stress, as per ICH specified conditions. The drug underwent significant degradation under hydrolytic (acidic, alkaline and neutral) and oxidative stress conditions whereas, it was found to be stable under other stress conditions. A rapid, precise, accurate and robust chromatographic method for the separation of the drug and its degradation products (DPs) was developed on a Fortis C18 analytical column (150×4.6mm, 5µm) using 0.1% formic acid and acetonitrile as a mobile phase in gradient elution mode at a flow rate of 1.0mL/min. A total of 5 (DP 1 to DP 5) hitherto unknown DPs were identified by LC-ESI-TOF-MS/MS experiments and accurate mass measurements. The most probable mechanisms for the formation of DPs have been proposed based on a comparison of the fragmentation of the [M+H]+ ions of silodosin and its DPs. The major DPs (DP 1 and DP 2) were isolated and evaluated for anticancer activity using PC3 (human prostate cancer) cell lines by MTT assay. The results revealed that silodosin, DP 1 and DP 2 have potential anticancer activity with IC50 values (µM) 72.74 (±4.51), 25.21 (±2.36), and, 114.07 (±11.90) respectively.

Synthesis and biological evaluation of oxindole linked indolyl-pyrimidine derivatives as potential cytotoxic agents.

In our endeavor towards the development of effective cytotoxic agents, a series of oxindole linked indolyl-pyrimidine derivatives were synthesized and characterized by IR, (1)H NMR, (13)C NMR and Mass spectral analysis. All the newly synthesized target compounds were assessed against PA-1 (ovarian), U-87MG (glioblastoma), LnCaP (prostate), and MCF-7 (Breast) cancer cell lines for their cytotoxic potential, with majority of them showing inhibitory activity at low micro-molar concentrations. Significantly, compound 8e was found to be most potent amongst all the tested compounds with an IC50 value of (2.43±0.29µM) on PA-1 cells. The influence of the most active cytotoxic compound 8e on the cell cycle distribution was assessed on the PA-1 cell line, exhibiting a cell cycle arrest at the G2/M phase. Moreover, acridine orange/ethidium bromide staining and annexin V binding assay confirmed that compound 8e can induce cell apoptosis in PA-1 cells. These preliminary results persuade further investigation on the synthesized compounds aiming to the development of potential cytotoxic agents.