Yini Cao

Recent Advances in Dendrimer Research for Cardiovascular Diseases.

Dendrimers, as a type of artificially synthesized polymers, have been increasingly attracting attention in many research fields, including the material and medical sciences, due to their unique characteristics that include their highly branched and well-defined molecular architecture, multivalency and tunable chemical compositions. These advantages make dendrimers potential carriers for the delivery of therapeutic and diagnostic agents. Herein, we review the recent advances in dendrimer research for the prevention and treatment of cardiovascular diseases, with special focus on their applications as carriers for drug and gene delivery, as contrast agents, and as potential new drugs.

G5 PAMAM dendrimer versus liposome: A comparison study on the in vitro transepithelial transport and in vivo oral absorption of simvastatin

UNLABELLED This study compared formulation effects of a dendrimer and a liposome preparation on the water solubility, transepithelial transport, and oral bioavailability of simvastatin (SMV). Amine-terminated G5 PAMAM dendrimer (G5-NH2) was chosen to form SMV/G5-NH2 molecular complexes, and SMV-liposomes were prepared by using a thin film dispersion method. The effects of these preparations on the transepithelial transport were investigated in vitro using Caco-2 cell monolayers. Results indicated that the solubility and transepithelial transport of SMV were significantly improved by both formulations. Pharmacokinetic studies in rats also revealed that both the SMV/G5-NH2 molecular complexes and the SMV-liposomes significantly improved the oral bioavailability of SMV with the liposomes being more effective than the G5-NH2. The overall better oral absorption of SMV-liposomes as compared to SMV/G5-NH2 molecular complexes appeared to arise from better liposomal solubilization and encapsulation of SMV and more efficient intracellular SMV delivery. FROM THE CLINICAL EDITOR Various carrier systems have been designed to enhance drug delivery via the oral route. In this study, the authors compared G5 PAMAM dendrimers to liposome preparations in terms of solubility, transepithelial transport, and oral bioavailability of this poorly water-soluble drug. This understanding has improved our knowledge in the further development of drug carrier systems.

Oral absorption enhancement of probucol by PEGylated G5 PAMAM dendrimer modified nanoliposomes.

Probucol (PB), an antioxidant drug, is commonly used as a lipid concentration lowering drug to reduce blood plasma cholesterol levels in the clinic. However, the therapeutic effects of this drug are negatively impacted by its poor water solubility and low oral absorption efficiency. In this study, a PEGylated G5 PAMAM dendrimer (G5-PEG) modified nanoliposome was employed to increase water solubility, transepithelial transport, and oral absorption of PB. The uptake mechanism was explored in vitro in Caco-2 cells with the results suggesting that the absorption improvement of G5-PEG modified PB-liposome (PB-liposome/G5-PEG) was related to P-glycoprotein (P-gp) efflux pump but was independent of caveolae endocytosis pathways. Additionally, plasma lipid concentration lowering effects of PB-liposome/G5-PEG were evaluated in vivo in a LDLR-/- hyperlipidemia mouse model. Compared with saline treated group, treatment with PB-liposome/G5-PEG significantly inhibited the increase of plasma total cholesterol (TC) and triglyceride (TG) of mice induced by a high fat diet. Moreover, its lipid concentration lowering effects and plasma drug concentration were greater than PB alone or commercial PB tablets. Our results demonstrated that PB-liposome/G5-PEG significantly increased the oral absorption of PB and therefore significantly improved its pharmacodynamic effects.

A review of molecular imaging of atherosclerosis and the potential application of dendrimer in imaging of plaque

Despite the fact that technological advancements have been made in diagnosis and treatment, cardiovascular diseases (CVDs) remain the leading cause of mortality and morbidity worldwide. Early detection of atherosclerosis (AS), especially vulnerable plaques, plays a crucial role in the prevention of acute coronary syndrome (ACS). Targeting the critical cytokines and molecules that are upregulated during the biological process of AS by in vivo molecular imaging has been widely used in plaque imaging. With their three-dimensional architecture, composition, and abundant terminal functional groups, dendrimers provide a platform for multitargeting and multimodal imaging. Thus, modified dendrimers with the key molecules upregulated in AS plaques will be an innovative attempt to achieve targeted imaging of AS plaques specifically and efficiently. This review was aimed to address some recent works on imaging of AS plaques using various types of image technology and further discuss the applications of dendrimers, an innovative yet seldom used method in imaging of AS plaques due to some limitations and challenges, and we highlight the bright future of the modified dendrimers in characterizing AS plaques.

Thermosensitive Hydrogel Containing Doxycycline Exerts Inhibitory Effects on Abdominal Aortic Aneurysm Induced By Pancreatic Elastase in Mice

Doxycycline (DOX) is reported to exert therapeutic effects against abdominal aortic aneurysm (AAA), a severe degenerative disease. In this study, a DOX hydrogel formulation of DOX/PECTgel is studied, and its phase transition behavior and in vitro release profiles are explored. In addition, the anti-AAA effects and bioavailability of DOX/PECTgel are evaluated in an elastase induced AAA mouse model. The results show that the phase transition temperature of 30% poly(e-caprolactone-co-1,4,8-trioxa[4.6]spiro-9-undecanone) (PECT) solution is above 34 °C. In vitro release profiles of DOX/PECTgel indicate a fast release of DOX at the first two days, followed by a slow and sustained release for 14 d. In vivo single-dose single subcutaneous injection of DOX/PECTgel containing 8.4 or 4.2 mg mL-1 DOX presents comparatively preventive effects on AAA, compared to intraperitoneal injections of DOX alone at a dose of 15 mg kg-1 for seven injections, while DOX bioavailability of the DOX/PECTgel treated groups is 1.39 times or 1.19 times of the DOX alone treated group, respectively.

Fenofibrate nanoliposome: Preparation and its inhibitory effects on nonalcoholic fatty liver disease in mice

The aim was to prepare fenofibrate nanoliposome (FNB-Nanolipo) and investigate its characterizations, oral pharmacokinetic (PK) profiles as well as preventive and therapeutic effects on nonalcoholic fatty liver disease (NAFLD) induced by a methionine choline deficient (MCD) diet in mice. The prepared FNB-Nanolipo showed high drug loading capacity and sustained in vitro FNB release profile. Compared to FNB crude drug at equal doses, the FNB-Nanolipo given at 20 mg/kg/day (beginning on the same day when the MCD diet feeding started and lasted for 7 days) or 40 mg/kg/day (beginning after 7 days of the MCD diet feeding and lasting for another 7 days together with the MCD diet) increased plasma FNB concentration of the mice by 11.8-fold (P<0.05) or 57.3-fold (P<0.001), respectively, and reduced 54.7% (P<0.05) or 35.5% (P<0.05) of excessive hepatic lipid, respectively. The results suggest that the FNB-Nanolipo could not only significantly prevent but also efficiently treat NAFLD.

Polyurethane nanoparticles loaded fenofibrate exerts inhibitory effects on nonalcoholic fatty liver disease in mice

Polyurethane (PU) nanoparticles are potential drug carriers. We aimed to study the in vitro and in vivo efficacy of biodegradable PU nanoparticles loaded with fenofibrate (FNB-PU) on nonalcoholic fatty liver disease (NAFLD). FNB-PU was prepared by a green process, and its preventive effects on NAFLD were investigated on HepG2 cells and mice. FNB-PU showed sustained in vitro FNB release profile. Compared to FNB crude drug, FNB-PU significantly decreased triglyceride content in HepG2 cells incubated with oleic acid and in livers of mice with NAFLD induced by a methionine choline deficient diet, and increased plasma FNB concentration of the mice. FNB-PU increased absorption of FNB and therefore enhanced the inhibitory effects of FNB on NAFLD.

Inhibitory Effects of Cycloastragenol on Abdominal Aortic Aneurysm and its Related Mechanisms: Cycloastragenol inhibits AAA

Abdominal aortic aneurysm (AAA) is a degenerative disease affecting human health, but there are no safe and effective medications for AAA therapy. Cycloastragenol (CAG), derived from Astragali Radix, has various pharmacological effects. However, whether CAG can protect against AAA remains elusive. In this study, we investigated whether CAG has an inhibitory effect on AAA and its related mechanism.

Grape-seed Polyphenols Play a Protective Role in Elastase-induced Abdominal Aortic Aneurysm in Mice

Abdominal aortic aneurysm (AAA) is a kind of disease characterized by aortic dilation, whose pathogenesis is linked to inflammation. This study aimed to determine whether grape-seed polyphenols (GSP) has anti-AAA effects and what mechanism is involved, thus to find a way to prevent occurrence and inhibit expansion of small AAA. In our study, AAA was induced by incubating the abdominal aorta of the mice with elastase, and GSP was administrated to the mice by gavage at different doses beginning on the day of the AAA inducement. In in vivo experiments, 800 mg/kg GSP could significantly reduce the incidence of AAA, the dilatation of aorta and elastin degradation in media, and dramatically decrease macrophage infiltration and activation and expression of matrix metalloproteinase (MMP) −2 and MMP-9 in the aorta, compared to the AAA model group. Meanwhile, 400 mg/kg GSP could also but not completely inhibit the occurrence and development of AAA. In in vitro experiments, GSP dose-dependently inhibited mRNA expression of interleukin (IL)-1β, IL-6 and monocyte chemoattractant protein-1 (MCP-1), and significantly inhibited expression and activity of MMP-2 and MMP-9, thus prevented elastin from degradation. In conclusion, GSP showed great anti-AAA effects and its mechanisms were related to inhibition of inflammation.

Nanoliposome improves inhibitory effects of naringenin on nonalcoholic fatty liver disease in mice

AIM To prepare naringenin nanoliposome (NRG-Nanolipo) and investigate its inhibitory effects on nonalcoholic fatty liver disease (NAFLD). MATERIALS & METHODS NRG-Nanolipo was prepared by thin-film rehydration method. Its characterizations and effects on NAFLD in mice induced by methionine choline deficient diet were investigated. RESULTS NRG-Nanolipo had high-drug loading percentage and showed a sustained release profile. The nanoliposome formulation significantly increased oral absorption of naringenin (NRG). NRG-Nanolipo showed comparable inhibitory effects as NRG crude drug at a dose fourfold lower than the crude drug on NAFLD. CONCLUSION It is the first study to report the inhibitory effects of NRG on NAFLD, and the NRG-Nanolipo significantly improved oral absorption of NRG, thus improved liver protective effects of NRG on NAFLD.