Effect of intravitreal anti-vascular endothelial growth factor on corneal endothelial cell count and central corneal thickness in Indian population

Purpose

To evaluate the effect of intravitreal anti-VEGF on corneal endothelial cell count and central corneal thickness as well as to compare these in phakic and pseudophakic eyes.

Material and Methods

The study was conducted in 102 eyes selected, as per selection criteria, over a time period of 18 months. At first patient visit, examination included: 1. Fundus examination. 2. Specular microscopy was done to look for endothelial cell count and Central corneal thickness. At second visit, Injection 0.5 mg/0.05 ml of ranibizumab was administered. Visits at day 1, day 7 and 1 month were done for Endothelial cell density and central corneal thickness was measured by specular microscope.

Results

The mean CCT value in pseudophakic group was 502.08 ± 19.91, 501.9 ± 20.31, and 501.72 ± 21.55 on day 1, 7 and 30, respectively. The mean CCT value in phakic group was 506.53 ± 22.61, 505.96 ± 20.12, 505.92 ± 20.3 and 505.69 ± 21.47. The mean value of ECD in pseudophakic eyes on day 1, 7, and 30 were 2284.24 ± 299.86, 2281.39 ± 289.46 and 2284.06 ± 312.65 cells/mm², respectively. The mean value of ECD in phakic eyes on day 1, 7, and 30 were 2314.51 ± 212.08, 2313.92 ± 212.7 and 2313.63 ± 216.86 cells/mm², respectively.

Conclusion

There is no significant change in endothelial cell density, central corneal thickness, coefficient of variation and intraocular pressure before and after intravitreal injection over one month of follow-up. The results are similar between phakic and pseudophakic eyes.

Pharmacokinetic analysis and tissue distribution of andrographolide in rat by a validated LC-MS/MS method

CONTEXT

Andrographis paniculata (Burm.f.) Nees (Acanthaceae) is widely used in tribal medicine in India and some other countries for multiple clinical applications. It contains andrographolide (AG) (diterpenoid lactone), a major phytomarker which probably accounts for its medicinal properties.

OBJECTIVE

This study investigates the site-specific distribution of AG in different tissues of rats and its pharmacokinetic parameter evaluation by using a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method.

MATERIALS AND METHODS

A simple and sensitive LC-MS/MS method has been developed and validated to quantify the presence of AG in plasma and various tissues of rat following oral administration of A. paniculata extract and AG in a dose of 133.33 and 100 mg/kg/day, respectively, for four weeks.

RESULTS

The present study showed that the highest concentration of AG was in kidney (156.12 ng/g) followed by liver, spleen and brain while almost same concentration was found in heart and lung. The apparent C(max), T(max), elimination half-life and total exposure (AUC(0-α)) were 115.81 ng/ml, 0.75, 2.45 and 278.44 ngh/ml, respectively.

CONCLUSION

This was an attempt to determine the presence of AG (a known biomarker) in tissues such as kidney, heart, lungs, brain and plasma of rats using a validated LC-MS/MS method. Furthermore, the observed reduced concentration in plasma and various tissues from 1 to 8 h might be attributed to relatively rapid elimination or distribution of AG from the central compartment.

Nanoemulsion strategy for olmesartan medoxomil improves oral absorption and extended antihypertensive activity in hypertensive rats

Olmesartan medoxomil (OM) is hydrolyzed to its active metabolite olmesartan by the action of aryl esterase to exert its antihypertensive actions by selectively blocking angiotensin II-AT1 receptor. Poor aqueous solubility and uncontrolled enzymatic conversion of OM to its poorly permeable olmesartan limits its oral bioavailability. The aim of the current study was to formulate a novel nanoemulsion of OM to improve its pharmacokinetics and therapeutic efficacy. The oil-in-water (o/w) nanoemulsion of OM was developed using lipoid purified soybean oil 700, sefsol 218 and solutol HS 15. We have characterized the nanoemulsions by considering their thermodynamic stability, morphology, droplet size, zeta potential and viscosity and in vitro drug release characteristics in fasting state simulated gastric fluid (pH 1.2) and intestinal fluid (pH 6.5). The thermodynamically stable nanoemulsions comprises of spherical nanometer sized droplets (<50 nm) with low polydispersity index showed enhanced permeability through the Caco-2 cell monolayer. The concentration of active olmesartan in rat plasma following oral absorption study was determined by our validated LC-MS/MS method. The result of the pharmacokinetic study showed 2.8-fold increased in area under the curve (AUC0-27) of olmesartan upon oral administration of OM nanoemulsion and sustained release profile. Subsequent, in vivo studies with nanoemulsion demonstrated better and prolonged control of experimentally induced hypertension with 3-fold reduction in conventional dose. By analysing the findings of the present investigations based on stability study, Caco-2 permeability, pharmacokinetic profile and pharmacodynamic evaluation indicated that the nanoemulsion of OM (OMF6) could significantly enhance the oral bioavailability of relatively insoluble OM contributing to improved clinical application.

A report on anti-oedemogenic activity of Byttneria herbacea roots--possible involvement of histamine receptor (type I)

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional healers of the Kol tribes of West Bengal, Bihar and Jharkhand (India), widely use the woody rootstock of Byttneria herbacea to reduce the swelling of limbs, due to filariasis. Besides filariasis different part of this plant is used for the treatment of cholera, diarrhoea and asthma.

AIM OF THIS STUDY

This study is a preliminary attempt to evaluate the anti-oedemogenic activity of the roots of Byttneria herbacea.

MATERIALS AND METHODS

The anti-oedemogenic activity of the hydroalcoholic extract of the roots of Byttneria herbacea (HBH) was evaluated against carrageenan and histamine induced rat paw oedema, acetic acid induced writhing and histamine induced vascular permeability in mice. Further, the effect of HBH on the expression of human histamine receptor type I (H1R) was studied in HeLa cells.

RESULTS

HBH exhibited significant dose-dependent inhibition (*p<0.05) against carrageenan and histamine induced rat paw oedema. Similar significant dose-dependent inhibition was observed against acetic acid induced writhing and histamine-induced vascular permeability in mice. Moreover, H1R specific mRNA expression was also significantly (*p<0.05) suppressed by HBH.

CONCLUSION

HBH was observed to possess anti-oedemogenic activity which is probably mediated through suppression of H1R.

Wnt/Shh interactions regulate ectodermal boundary formation during mammalian tooth development

Interactions between the Wnt (wingless) and hedgehog signaling pathways were first described as playing a role in establishing boundaries between ectodermal cells in Drosophila segmentation. During the initiation of mammalian tooth development, boundaries that distinguish oral from dental ectoderm must be formed to correctly position the sites of tooth formation. We describe a reciprocal relationship between the expression of Wnt-7b in presumptive oral ectoderm and Shh in presumptive dental ectoderm in mouse embryos that mark boundaries between these cells with different developmental fates. By using a murine retrovirus to ectopically express Wnt-7b in presumptive dental ectoderm in mandibular arch explants, we show that Shh expression in the ectoderm and Ptc expression in the underlying ectomesenchyme are down-regulated, and tooth development is subsequently arrested. This suggests that Wnt-7b acts to repress Shh expression in oral ectoderm, thus maintaining the boundaries between oral and dental ectodermal cells. Implantation of beads soaked in Shh protein into Wnt-7b-infected explants resulted in complete rescue of tooth development, confirming that the repressive action of Wnt-7b specifically affects Shh signaling.

Inhibition of Wnt signaling by exogenous Mfrzb1 protein affects molar tooth size

Wnt extracellular signaling molecules have essential roles as regulators of cell proliferation, migration, differentiation, and in epithelial-mesenchymal interactions involved in tissue morphogenesis. Frizzled integral membrane proteins have been shown to function as receptors for Wnt signaling molecules. Vertebrates also produce secreted proteins related to Frizzled receptors, Frizzled-related proteins (FRPs), which contain the cysteine-rich domain of Frizzleds and appear to function as Wnt antagonists. Tooth development is regulated by a reciprocal series of epithelial-mesenchymal interactions, and many Wnt signaling pathway genes are expressed in the developing tooth at these sites. Here we report the expression of one FRP gene, Mfrzb1, in the rostral mesenchyme of the mandibular primordium. Using explant cultures, we show that expression of Mfrzb1 in the mandibular mesenchyme is under the control of signals derived from the overlying epithelium. Bead implantation experiments in vitro show that FGF8 induces Mfrzb1 expression, whereas BMP4 and SHH proteins have no effect. We studied the effect of ectopic MFrzb1 protein on the developing tooth germs by transplanting explants treated with Mfrzb1 protein into renal capsules, and found it to retard tooth development. This suggests that Wnt signaling is required early in tooth germ formation and that interference with signaling via addition of an antagonist results in retarded development and formation of smaller teeth.

Expression of Wnt signalling pathway genes during tooth development

We have carried out comparative in situ hybridisation analysis of six Wnt genes Wnts-3, -4, -5a, -6, -7b, and 10b together with Wnt receptor MFz6 and receptor agonist/antagonists MFrzb1 and Mfrp2 during murine odontogenesis from the earliest formation of the epithelial thickening to the early bell stage. Expression of Wnt-4, Wnt-6, and one Wnt receptor MFz6 was observed in the facial, oral and dental epithelium. Wnt10b was localised specifically to the presumptive dental epithelium. Wnts-3 and -7b were expressed in oral epithelium but showed no expression in the presumptive dental epithelium. Wnt-3 also showed no expression in the epithelial cells of the molar bud stage tooth germs, but showed restricted expression in the enamel knots which are signalling centres believed to be involved in regulating tooth shape. Wnts -6, -10b and MFz6 were also detected in the primary and secondary enamel knots. Wnt-5a and agonist/antagonists MFrzb1 and Mfrp2 were expressed in a graded proximo-distal (P-D) manner in mesenchymal cells during the early stages of tooth development with no overlying expression in the oral or dental epithelium. Wnt-5a and MFrzb1 show strong expression in the dental papilla mesenchyme.