Discovery of Dipyridamole Analogues with Enhanced Metabolic Stability for the Treatment of Idiopathic Pulmonary Fibrosis

Dipyridamole, apart from its well-known antiplatelet and phosphodiesterase inhibitory activities, is a promising old drug for the treatment of pulmonary fibrosis. However, dipyridamole shows poor pharmacokinetic properties with a half-life (T_1/2) of 7 min in rat liver microsomes (RLM). To improve the metabolic stability of dipyridamole, a series of pyrimidopyrimidine derivatives have been designed with the assistance of molecular docking. Among all the twenty-four synthesized compounds, compound (S)-4h showed outstanding metabolic stability (T_1/2 = 67 min) in RLM, with an IC₅₀ of 332 nM against PDE5. Furthermore, some interesting structure–activity relationships (SAR) were explained with the assistance of molecular docking.     

Proteomic Insights into Cardiac Fibrosis: From Pathophysiological Mechanisms to Therapeutic Opportunities

Cardiac fibrosis is a common pathophysiologic process in nearly all forms of heart disease which refers to excessive deposition of extracellular matrix proteins by cardiac fibroblasts. Activated fibroblasts are the central cellular effectors in cardiac fibrosis, and fibrotic remodelling can cause several cardiac dysfunctions either by reducing the ejection fraction due to a stiffened myocardial matrix, or by impairing electric conductance. Recently, there is a rising focus on the proteomic studies of cardiac fibrosis for pathogenesis elucidation and potential biomarker mining. This paper summarizes the current knowledge of molecular mechanisms underlying cardiac fibrosis, discusses the potential of imaging and circulating biomarkers available to recognize different phenotypes of this lesion, reviews the currently available and potential future therapies that allow individualized management in reversing progressive fibrosis, as well as the recent progress on proteomic studies of cardiac fibrosis. Proteomic approaches using clinical specimens and animal models can provide the ability to track pathological changes and new insights into the mechanisms underlining cardiac fibrosis. Furthermore, spatial and cell-type resolved quantitative proteomic analysis may also serve as a minimally invasive method for diagnosing cardiac fibrosis and allowing for the initiation of prophylactic treatment.     

Synthesis of triterpenoid derivatives and their anti-tumor and anti-hepatic fibrosis activities

Abstract

Oleanolic acid (1), ursolic acid (2), hederagenin (3), betulinol (4), betulinic acid (5), and glycyrrhetinic acid (6) are obtained from acorn/licorice industrial wastes with common triterpenoid structure as a model set for esterification. Eight 3,4,5-methoxybenzoyl triterpenoid derivatives (1a–6a), including four new derivatives (1a, 3a–1, 3a–2, and 3a–3), are synthesized by classical procedures. Their antitumor and anti-hepatic fibrosis activities are evaluated on four human tumor cell lines and t-HSC/Cl-6 cells. Derivative 1a shows maximum antiproliferative effects against all cell lines, especially against tumor cells with IC₅₀ values in the range of 5.32–15.23?μM, but does not affect the viability of normal cells. The anti-tumor mechanisms of 1a are also investigated by western blot and docking studies. The 3,4,5-methoxybenzoyl triterpenoids offers an intriguing solution for naturally derived antitumor drugs and may be invaluable for further development of cancer therapy.     

Citric acid-loaded W1/O/W2 multiple emulsions efficiently remove colonic ammonia both in vitro and in vivo

Hepatic encephalopathy (HE) is a neuropsychiatric disorder caused by chronic and acute liver diseases. It is believed that ammonia played an important role on the pathogenesis of the disease. Herein, acid-loaded water-in-oil-in-water (W₁/O/W₂) multiple emulsions with over 95% encapsulation efficiency were prepared and used to absorb colonic ammonia. The study of citric acid release from W₁ to W₂ in bulk deionized water indicated that only 17% acid released in 8 hours, which proved the stability of the multiple emulsions and hence prevented the intestine from being irritated by acid burst release. In vitro, the W₁/O/W₂ emulsion could remove around 90% ammonia in 1.5 hours from either the 3 mmol/L ammonia solution or the artificial colonic fluid with 1 and 0.5 mmol/L ammonia without acidifying the artificial colonic fluid. In vivo, compared with lactulose, W₁/O/W₂ emulsions could efficiently reduce the blood ammonia to the similar level in the rat models with HE without increasing the water content in feces. All these results indicated a potential application of W₁/O/W₂ multiple emulsions for the treatment of HE.     

Sodium tanshinone IIA sulfonate attenuates angiotensin II-induced collagen type I expression in cardiac fibroblasts in vitro

Cardiac fibrosis occurs after pathological stimuli to the cardiovascular system. One of the most important factors that contribute to cardiac fibrosis is angiotensin II (Ang II). Accumulating studies have suggested that reactive oxygen species (ROS) plays an important role in cardiac fibrosis and sodium tanshinone IIA sulfonate (STS) possesses antioxidant action. We therefore examined whether STS depresses Ang II-induced collagen type I expression in cardiac fibroblasts. In this study, Ang II significantly enhanced collagen type I expression and collagen synthesis. Meanwhile, Ang II depressed matrix metalloproteinase-1 (MMP-1) expression and activity. These responses were attenuated by STS. Furthermore, STS depressed the intracellular generation of ROS, NADPH oxidase activity and subunit p47^phox expression. In addition, N-acetylcysteine the ROS scavenger, depressed effects of Ang II in a manner similar to STS. In conclusion, the current studies demonstrate that anti-fibrotic effects of STS are mediated by interfering with the modulation of ROS.     

Identification of the commonest cystic fibrosis transmembrane regulator gene DeltaF508 mutation: evaluation of PCR--single-strand conformational polymorphism and polyacrylamide gel electrophoresis

In the present study we investigated whether single-strand conformational polymorphism (SSCP) and polyacrylamide gel electrophoresis (PAGE) could be used for the identification of the CFTR DeltaF508 gene mutation, which is commonest in the Greek population. Using DNA from patients carrying this mutation, the appropriate 98 bp region of the CFTR gene was amplified by PCR and the reaction products were analysed by non-radioactive SSCP-electrophoresis using silver staining for band visualization and non-denaturating PAGE to confirm the results. SSCP electrophoretic analysis has been optimized for several parameters in order to achieve the best resolution. Single-strand DNA fragments gave a reproducible pattern of bands, characteristic for the particular mutation. Comparison of the obtain patterns with control samples allowed the detection of the DeltaF508 mutation in the patients studied by SSCP assay and these results were confirmed by the independent method of PAGE. Although SSCP and PAGE can be used for detection of this mutation, PAGE resulted in more distinct patterns than SSCP. It is, therefore, proposed that PAGE can be reliably used for the detection and identification of such a mutation in patients provided that suitable controls are available. The applicability of PAGE to identification of the mutation in carriers, particularly useful for population screening, is also discussed.     

Influence of sialic acid and bacterial sialidase on differential adhesion of Pseudomonas aeruginosa to epithelial cells

Epithelial cell lines from several tissues show a differential sensitivity to Pseudomonas aeruginosa adherence. A549 (lung), HepG2 (liver) and Caco-2 (colon) cells presented an adhesion index of about 3, 1.5 and 5 CFU/cell, respectively, whereas Mz-Ch cell lines (gallbladder cholangiocytes) presented adhesion indexes up to 35. These variations could be associated with the variable amount of sialic acid in cell surface glycoconjugates. Moreover, the presence of free sialic acid in culture media induces the secretion by P. aeruginosa of a sialidase which is able to hydrolyze glycoconjugate-linked sialic acid. As shown with A549 cells, this specific hydrolysis increases bacterial adhesion, probably by unmasking new binding sites onto the cell surface.     

Transcutaneous application of carbon dioxide improves contractures after immobilization of rat knee joint

Objective: Joint contractures are a major complication following joint immobilization. However, no fully effective treatment has yet been found. Recently, carbon dioxide (CO₂) therapy was developed and verified this therapeutic application in various disorders. We aimed to verify the efficacy of transcutaneous CO₂ therapy for immobilization-induced joint contracture. Method: Twenty-two Wistar rats were randomly assigned to three groups: caged control, those untreated after joint immobilization, and those treated after joint immobilization. The rats were treated with CO₂ for 20 min once a daily either during immobilization, (prevention) or during remobilization after immobilization (treatment). Knee extension motion was measured with a goniometer, and the muscular and articular factors responsible for contractures were calculated. We evaluated muscle fibrosis, fibrosis-related genes (collagen Type 1α1 and TGF-β1) in muscles, synovial intima''s length, and fibrosis-related proteins (Type I collagen and TGF-β1) in the joint capsules. Results: CO₂ therapy for prevention and treatment improved the knee extension motion. Muscular and articular factors decreased in rats of the treatment group. The muscular fibrosis of treated rats decreased in the treatment group. Although CO₂ therapy did not repress the increased expression of collagen Type 1α1, the therapy decreased the expression of TGF-β1 in the treatment group. CO₂ therapy for treatment improved the shortening of the synovial membrane after immobilization and decreased the immunolabeling of TGF-β1 in the joint capsules. Conclusions: CO₂ therapy may prevent and treat contractures after joint immobilization, and appears to be more effective as a treatment strategy for the deterioration of contractures during remobilization.     

The putative use of alpha-1-acid glycoprotein as a non-invasive marker of fibrosis

The acute phase response to injury or infection results in alterations in the expression of the plasma proteins produced by the liver. Many of these biomolecules are glycosylated with oligosaccharide chains covalently attached to the polypeptide backbone and the extent and composition of this glycosylation can be altered in a disease-dependent manner. Of particular interest is the observation that the acute phase glycoprotein, alpha-1-acid glycoprotein (AGP) has altered glycosylation in several physiological and pathological conditions. It is posited that changes induced in liver diseases may reflect disease severity and may therefore act as a non-invasive marker of fibrosis. This study has investigated the glycosylation of AGP in the plasma of people with varying degrees of cirrhosis and fibrosis. Hyperfucosylation was observed in all disease samples in comparison to normal plasma and was significantly increased in cirrhosis. Both sialic acid and N-acetylgalactosamine (GalNAc) were negatively associated with fibrosis. Two samples were found to express GalNAc, which as a constituent of the glycosylation of serum proteins is rare. In conclusion, fucose, sialic acid and other aspects of the glycosylation of AGP are influenced by the degree of fibrosis and as such may prove a valuable prognostic indicator of the development of cirrhosis.