Pre-clinical model of severe glutathione peroxidase-3 deficiency and chronic kidney disease results in coronary artery thrombosis and depressed left ventricular function.

Background: Chronic kidney disease (CKD) patients have deficient levels of glutathione peroxidase-3 (GPx3). We hypothesized that GPx3 deficiency may lead to cardiovascular disease in the presence of chronic kidney disease due to an accumulation of reactive oxygen species and decreased microvascular perfusion of the myocardium. Methods. To isolate the exclusive effect of GPx3 deficiency in kidney disease-induced cardiac disease, we studied the GPx3 knockout mouse strain (GPx3-/-) in the setting of surgery-induced CKD. Results. Ribonucleic acid (RNA) microarray screening of non-stimulated GPx3-/- heart tissue show increased expression of genes associated with cardiomyopathy including myh7, plac9, serpine1 and cd74 compared with wild-type (WT) controls. GPx3-/- mice underwent surgically induced renal mass reduction to generate a model of CKD. GPx3-/- + CKD mice underwent echocardiography 4 weeks after injury. Fractional shortening (FS) was decreased to 32.9 ± 5.8% in GPx3-/- + CKD compared to 62.0% ± 10.3 in WT + CKD (P < 0.001). Platelet aggregates were increased in the myocardium of GPx3-/- + CKD. Asymmetric dimethylarginine (ADMA) levels were increased in both GPx3-/- + CKD and WT+ CKD. ADMA stimulated spontaneous platelet aggregation more quickly in washed platelets from GPx3-/-. In vitro platelet aggregation was enhanced in samples from GPx3-/- + CKD. Platelet aggregation in GPx3-/- + CKD samples was mitigated after in vivo administration of ebselen, a glutathione peroxidase mimetic. FS improved in GPx3-/- + CKD mice after ebselen treatment. Conclusion: These results suggest GPx3 deficiency is a substantive contributing factor to the development of kidney disease-induced cardiac disease.

Human vascular progenitor cells derived from renal arteries are endothelial-like and assist in the repair of injured renal capillary networks.

Vascular progenitor cells show promise for the treatment of microvasculature endothelial injury. We investigated the function of renal artery progenitor cells derived from radical nephrectomy patients, in animal models of acute ischemic and hyperperfusion injuries. Present in human adventitia, CD34positive/CD105negative cells were clonal and expressed transcription factors Sox2/Oct4 as well as surface markers CXCR4 (CD184)/KDR(CD309) consistent with endothelial progenitor cells. Termed renal artery-derived vascular progenitor cells (RAPC), injected cells were associated with decreased serum creatinine after ischemia/reperfusion, reduced albuminuria after hyperperfusion, and improved blood flow in both models. A small population of RAPC integrated with the renal microvasculature following either experimental injury. At a cellular level, RAPC promoted local endothelial migration in co-culture. Profiling of RAPC microRNA identified high levels of miRNA 218; also found at high levels in exosomes isolated from RAPC conditioned media after cell contact for 24 hours. After hydrogen peroxide-induced endothelial injury, RAPC exosomes harbored Robo-1 transcript; a gene known to be regulated by mir218. Such exosomes enhanced endothelial cell migration in culture in the absence of RAPC. Thus, our work shows the feasibility of pre-emptive pro-angiogenic progenitor cell procurement from a targeted patient population and potential therapeutic use in the form of autologous cell transplantation.

RGS4 inhibits angiotensin II signaling and macrophage localization during renal reperfusion injury independent of vasospasm.

Vascular inflammation is a major contributor to the severity of acute kidney injury. In the context of vasospasm-independent reperfusion injury we studied the potential anti-inflammatory role of the Gα-related RGS protein, RGS4. Transgenic RGS4 mice were resistant to 25 min injury, although post-ischemic renal arteriolar diameter was equal to the wild type early after injury. A 10 min unilateral injury was performed to study reperfusion without vasospasm. Eighteen hours after injury, blood flow was decreased in the inner cortex of wild-type mice with preservation of tubular architecture. Angiotensin II levels in the kidneys of wild-type and transgenic mice were elevated in a sub-vasoconstrictive range 12 and 18 h after injury. Angiotensin II stimulated pre-glomerular vascular smooth muscle cells (VSMCs) to secrete the macrophage chemoattractant RANTES, a process decreased by angiotensin II R2 (AT2) inhibition. However, RANTES increased when RGS4 expression was suppressed implicating Gα protein activation in an AT2-RGS4-dependent pathway. RGS4 function, specific to VSMC, was tested in a conditional VSMC-specific RGS4 knockout showing high macrophage density by T2 MRI compared with transgenic and non-transgenic mice after the 10 min injury. Arteriolar diameter of this knockout was unchanged at successive time points after injury. Thus, RGS4 expression, specific to renal VSMC, inhibits angiotensin II-mediated cytokine signaling and macrophage recruitment during reperfusion, distinct from vasomotor regulation.

Formulation, Evaluation, and Characterization of Ibuprofen Nanocrystals Tablets with Conventional Market Product.

The objective of this study was to prepare and evaluate ibuprofen nanocrystals using isopropyl alcohol and stabilizer sodium lauryl sulphate by way of the precipitation method. The nanocrystals were prepared by the bottom-up approach of the precipitation technique. This technique involves the use of an organic phase, which is completely miscible in the external aqueous phase. The ratio used for organic solvent-to-aqueous solvent was 1:50. The Fourier Transform Infrared Spectroscopy analyses confirmed that the drug and excipients were compatible, and the differential scanning calorimetry results indicated that the precipitation method led to no change in the crystalline structure of the drug. Scanning electron microscopy analysis of ibuprofen nanocrystals showed the promising size reduction of pure drug ibuprofen. Differential light scattering technique showed significant decrease in particle size and good stability of ibuprofen nanocrystals. Ibuprofen nanocrystals increased 20% to 25% of the saturation solubility of ibuprofen nanocrystals. Ibuprofen nanocrystals showed 90% drug release in the dissolution medium within 1 hour, while the pure drug and market product were dissolved only up to 58% and 63%, respectively. Ibuprofen nanocrystals increased the saturation solubility and in vitro dissolution of the drug as compared to conventional market product.

Design and Development of Agglomerated Isomalt.

The objective of this study was to prepare agglomerated isomalt by using the melt granulation process. This method involved the use of 99.5% of isomalt with the meltable binder glyceryl monostearate in a concentration of 0.5%. Glyceryl monostearate has a melting point of 50°C to 55°C, therefore, glyceryl monostearate was melted at its melting point and isomalt powder was blended with it to break the mass into agglomerates. The agglomerates were cooled to room temperature and were then screened to obtain granules of the desired size. The Fourier Transform Infrared Spectroscopy studies confirmed that the chemical structure of isomalt was not changed before and after the melt granulation process. A differential scanning calorimetry study showed that there was no appearance of more new peaks or disappearance of  one or more peaks corresponding to those of the isomalt powder and agglomerated isomalt, which showed no changes in the structure of the isomalt powder before and after the agglomeration process. The agglomerated isomalt and galenIQ 721 showed almost identical solubility profiles for g of solute per 100 g of solution at different temperatures. The scanning electron microscopy analysis of agglomerated isomalt showed promising results for the preparation of agglomerates of isomalt with glyceryl monostearate. The flow properties of the agglomerated isomalt compared with the galenIQ 721 and pure isomalt powder and melt granulation process showed promising results for agglomerated isomalt. The melt granulation process showed promising results to prepare agglomerates of the isomalt with the meltable binder glyceryl monostearate.