Synthetic cyclodextrin derivatives inhibit HIV infection in vitro

Comorbidities of HIV infection: role of Nef-induced impairment of cholesterol metabolism and lipid raft functionality

Combination antiretroviral therapy has dramatically changed the outcome of HIV infection, turning it from a death sentence to a manageable chronic disease. However, comorbidities accompanying HIV infection, such as metabolic and cardio-vascular diseases, as well as cognitive impairment, persist despite successful virus control by combination antiretroviral therapy and pose considerable challenges to clinical management of people living with HIV. These comorbidities involve a number of pathological processes affecting a variety of different tissues and cells, making it challenging to identify a common cause(s) that would link these different diseases to HIV infection. In this article, we will present evidence that impairment of cellular cholesterol metabolism may be a common factor driving pathogenesis of HIV-associated comorbidities. Potential implications for therapeutic approaches are discussed.

Cyclodextrins: Emerging Medicines of the New Millennium

Cyclodextrins, since their discovery in the late 19th century, were mainly regarded as excipients. Nevertheless, developments in cyclodextrin research have shown that some of these hosts can capture and include biomolecules, highlighting fatty acids and cholesterol, which implies that they are not inert and that their action may be used in specific medicinal purposes. The present review, centered on literature reports from the year 2000 until the present day, presents a comprehensive description of the known biological activities of cyclodextrins and their implications for medicinal applications. The paper is divided into two main sections, one devoted to the properties and applications of cyclodextrins as active pharmaceutical ingredients in a variety of pathologies, from infectious ailments to cardiovascular dysfunctions and metabolic diseases. The second section is dedicated to the use of cyclodextrins in a range of biomedical technologies.

Supramolecular Pharmaceutical Sciences: A Novel Concept Combining Pharmaceutical Sciences and Supramolecular Chemistry with a Focus on Cyclodextrin-Based Supermolecules

Supramolecular chemistry is an extremely useful and important domain for understanding pharmaceutical sciences because various physiological reactions and drug activities are based on supramolecular chemistry. However, it is not a major domain in the pharmaceutical field. In this review, we propose a new concept in pharmaceutical sciences termed "supramolecular pharmaceutical sciences," which combines pharmaceutical sciences and supramolecular chemistry. This concept could be useful for developing new ideas, methods, hypotheses, strategies, materials, and mechanisms in pharmaceutical sciences. Herein, we focus on cyclodextrin (CyD)-based supermolecules, because CyDs have been used not only as pharmaceutical excipients or active pharmaceutical ingredients but also as components of supermolecules.

Interactions between cyclodextrins and cellular components: Towards greener medical applications?

In the field of host-guest chemistry, some of the most widely used hosts are probably cyclodextrins (CDs). As CDs are able to increase the water solubility of numerous drugs by inclusion into their hydrophobic cavity, they have been widespread used to develop numerous pharmaceutical formulations. Nevertheless, CDs are also able to interact with endogenous substances that originate from an organism, tissue or cell. These interactions can be useful for a vast array of topics including cholesterol manipulation, treatment of Alzheimer's disease, control of pathogens, etc. In addition, the use of natural CDs offers the great advantage of avoiding or reducing the use of common petroleum-sourced drugs. In this paper, the general features and applications of CDs have been reviewed as well as their interactions with isolated biomolecules leading to the formation of inclusion or exclusion complexes. Finally, some potential medical applications are highlighted throughout several examples.

Cyclodextrin polysulphate protects articular cartilage in experimental lapine knee osteoarthritis

OBJECTIVE

To evaluate the in vivo chondroprotective effect of cyclodextrin polysulphate (CDPS) in a rabbit model of experimental osteoarthritis (OA).

DESIGN

Experimental OA was induced in rabbits by anterior cruciate ligament transection (ACLT). Forty-eight hours post-surgery, the rabbits were randomised into three treatment groups (n=15 in each group) and a sham-operated control group. The rabbits were either injected subcutaneously with saline, 0.25 mg/kg CDPS or 1 mg/kg CDPS once a week for a period of 12 weeks, and their weight was monitored as a parameter for their general status. The animals were then sacrificed for macroscopic and histological assessment of the knee joints.

RESULTS

At the lowest dose, CDPS treatment was unable to induce a significant improvement of cartilage degradation vs the saline control in the experimentally induced knee OA. However, subcutaneous injections of 1 mg/kg CDPS induced a marked inhibition (P<0.05) of osteophyte formation. Additionally, a significant reduction of cartilage degradation revealed an overall chondroprotective effect of CDPS at a concentration of 1 mg/kg. No significant effects on weight gain were noted.

CONCLUSIONS

Systemic administration of CDPS is able to protect cartilage in vivo and can therefore be considered as a chondroprotective agent with structure modifying capacities.

Applications of modified cyclodextrins

One of the key areas of importance in biotechnology and bioengineering is molecular complexation (MC). MC is useful in selectivity, separation, and solubilization of biomolecules. While many complex, natural MC agents exist, such as proteins and antibodies, relatively few engineered MC materials are available. Inorganic, insoluble MC agents, such as zeolites, are widely used in petroleum catalysis. Carbon Buckminster fullerenes ("bucky balls") can complex small neutral molecules, but are relatively insoluble and difficult to manufacture. Crown ethers have been used for molecular complexation, but are costly to synthesize and have limited capacities. One class of highly useful MC agents are cyclodextrins (CDs). These naturally-occurring, water-soluble cyclic glucans are used in a variety of food, pharmaceutical, and analytical applications. Due to the availability of multiple reactive hydroxyl groups, the functionality of CDs can be greatly increased through chemical modification. A host of new applications are being explored, including enzyme mimicry, molecular recognition, chromatographic separation, and solubilization. This review describes recent applications of modified cyclodextrins in bioprocessing and medicine.

Metachromatic activity of beta-cyclodextrin sulfates as heparin mimics

Heparin is a versatile biologically active substance which has been reported to have an inhibitory effect on angiogenesis if administered together with hydrocortisone. Since very little is known about the mechanism of this activity, beta-cyclodextrin sulfates were prepared to mimic heparin. The sulfate groups were introduced into beta-cyclodextrin regioselectively using protecting groups. The obtained polyanions were tested for their complex binding properties by mixing them with cationic dyes and measuring the metachromatic response which proved to be a very useful tool to evaluate the biological activity of these compounds. The results reveal that the activity depends largely upon the charge density at the surface of the beta-cyclodextrin sulfates: a large number of sulfate groups or anionic groups relatively close to each other display high activity, whereas molecules with fewer sulfate groups or with them more distant from each other exhibit smaller activities.

Beta cyclodextrins enhance adenoviral-mediated gene delivery to the intestine

PURPOSE

In general, the intestinal epithelium is quite refractory to viral and non-viral methods of gene transfer. In this report, various cyclodextrin formulations were tested for their ability to enhance adenoviral transduction efficiency in two models of the intestinal epithelium: differentiated Caco-2 cells and rat jejunum.

METHODS

Transduction efficiency of replication-deficient adenovirus type 5 vectors encoded with either the E. coli beta-galactosidase or the jellyfish green fluorescent protein gene was assessed by X-gal staining or visualization of fluorescence 48 hours after infection. In vivo experiments were performed using an intestinal loop ligation technique.

RESULTS

Several formulations of neutral and positively charged beta cyclodextrins significantly enhanced adenoviral-mediated gene transfer in the selected models. The cyclodextrin formulations studied increased adenoviral transduction in the intestine by enhancing both viral binding and internalization. Viral binding was significantly increased on cell membranes treated with positively charged cyclodextrins, as seen with confocal microscopy and rhodamine-labeled virus. Permeability studies and TEER readings revealed that the most successful formulations gently disrupt cell membranes. This enhances internalization of viral particles and results in increased levels of gene expression.

CONCLUSIONS

These formulations can be of value in gene transfer to cells and tissues in which adenoviral infection is limited due to a lack of fiber and alpha(v) integrin receptors. They are simple to prepare and do not affect the ability of the virus to transduce target cells.

A basic compositional requirement of agents having heparin-like cell-modulating activities

Heparin has been recognized as possessing a large variety of cell-modulating activities. Using compositionally simple, structurally rigid, and low molecular weight saccharide molecules (cyclodextrins), we demonstrated that these activities depend primarily on a single, gross compositional parameter: a minimum intramolecular density of neighboring anionic (sulfate) groups. This same critical parameter is shown to be involved in achieving cell-modulating behavior as diverse as angiogenesis, endothelial proliferation, inhibition of smooth muscle cell growth, and cell protection against virus invasion. Physical chemical evidence is presented that associates this property with multi-ionic complex formation between the clusters of anionic and cationic sites on the complexing partners. These observations revive early suggestions of the decisive role of electrostatic complexation capabilities of glycosaminoglycans like heparin; taken together with numerous observations on heparinoids and other agents reported in diverse specialized fields of cell biology and medicine, they provide evidence that molecular agents of critical anionic (sulfate) density (MACADs) represent a broad class of molecules that, in contrast to proteins, do not rely on structural detail for their cell biological activities, but function by ionic complexation with proteinic agents (e.g. growth factors), thereby modifying their structure-specific activities.

Use of cyclodextrin and its derivatives as carriers for oligonucleotide delivery

The use of antisense phosphorothioate oligodeoxynucleotides as tools for modulating gene expression represents a novel strategy for designing drugs to treat a variety of diseases. Several factors, including cellular uptake and internalization of the phosphorothioate oligodeoxynucleotide, are important parameters in determining the effectiveness of antisense agents as therapies. We have used cyclodextrin and its analogs as carriers to increase cellular uptake of phosphorothioate oligodeoxynucleotides. The studies were carried out using 35S-labeled and fluorescent-labeled phosphorothioate oligodeoxynucleotide in human T cell leukemia H9 cell line. Cellular uptake of phosphorothioate oligodeoxynucleotide in the presence of cyclodextrin was found to be concentration and time dependent. Using various cyclodextrin analogs, e.g., 2-hydroxypropyl beta-cyclodextrin (HPCD), hydroxyethyl beta-cyclodextrin (HECD), and a mixture of various hydroxypropyl beta-cyclodextrins (Encapsin), we observed increases in phosphorothioate oligodeoxynucleotide uptake, up to twofold to threefold in 48 hours. Confocal microscopy studies confirmed that oligonucleotide was present intracellularly. Cyclodextrin itself was not toxic at the concentration used. Cyclodextrins did not seem to affect the efflux of phosphorothioate oligodeoxynucleotide from cells. Stability of phosphorothioate oligodeoxynucleotide against endogenous cellular nucleases remained unchanged in the presence of cyclodextrins. These studies suggest that cyclodextrin and its analogs might be used successfully as carriers for oligonucleotide and analogs.

Protection of erythrocytes against hemolytic agents by cyclodextrin polysulfate

Cyclodextrins generally exhibit hemolytic activity, some at concentrations as low as 1-10 mg/mL or lower. However, we found previously that a highly polysulfated cyclodextrin has no demonstrable hemolytic activity (Macarak et al., Biochem Pharmacol 42: 1502-1503, 1991). In the present study, we determined that, in fact, cyclodextrin polysulfate (CDS) actively protected erythrocytes against hemolysis induced by a wide spectrum of hemolytically active substances, ranging from pharmaceuticals, such as chlorpromazine, to solid suspensions of siliceous particles. The protective action was also effective against the hemolytic action of non-sulfated cyclodextrins. The similar kinetic responses of the erythrocytes to CDS protection against such chemically and structurally diverse hemolytic agents suggest a common mechanism involving the cell. Addition of the sulfated cyclodextrins to other cyclodextrin compounds used to solubilize poorly soluble pharmaceutical agents can extend the allowable maximum dosage without deleterious hemolytic action.