An update on the potential for male contraception : emerging options

The human population continues to grow and is estimated to rise to 10.1 billion by the end of the century. Therefore, there is still an unmet need for safe and highly effective contraceptive options for both men and women. Current options available to men include withdrawal, condoms, and vasectomy. Methods in development fall into two categories: hormonal and nonhormonal. This review will provide an overview of the testosterone combinations and immunocontraception of hormonal targets. Nonhormonal immunocontraception of sperm proteins will also be examined, together with the use of agents to disrupt other sperm-associated targets and pathways. The categories focused on include epididymal proteins, testicular kinases, epigenetic reader proteins, opioids, lonidamine derivatives, retinoic acid, microRNAs associated with spermatogenesis, and plant extracts. Considering these developments, the number of options available to men is likely to increase in the near future

Control of malaria by bio-therapeutics and drug delivery systems

Malaria is an ubiquitous disease that can affect more than 40% of the world’s population who live with some risk of contracting this disease. The World Health Organization (WHO) has recently highlighted the high spread of this disease in Sub-Saharan Africa. Despite the considerable fall in mortality rate over the past decade, the development of resistance against main treatment strategies still exists. This problem has provoked scientific efforts to develop various treatment strategies including use of vaccines, drug delivery systems, and biotherapeutics approaches. A vaccination strategy is being implemented to trigger direct clearance of the causative parasites from the human host. However, the complex life-cycle of Plasmodium parasites with continuous antigenic mutations has partly hindered this approach so far. The application of different types of drug delivery systems for the delivery of anti-malarial drugs is also being considered in order to improve the efficacy, pharmacokinetics, tolerability, and reduce toxicity of existing anti-malarial drugs. A third approach has emerged from the high success of antibodies to treat complex diseases like cancer and autoimmune diseases. Various antibody engineering methods and formats have been proposed to tackle the notable sophisticated lifecycle of malaria. Within the malaria research field, the characteristics of these diverse treatment strategies, individually, are broadly acknowledged. This review article considers the current status of these approaches and the future outlook

Adjuvants : an essential component of neisseria vaccines

Adjuvants may be classified into delivery systems and immune potentiator or modulator molecules based on their mechanism of action. Neisseria vaccines containing traditional adjuvants such as aluminium salts have existed for long time, but meningitis caused by Neisseria meningitidis serogroups, particularly serogroup B, continues to be a global health problem. Novel strategies have applied in silico and recombinant technologies to develop "universal" antigens (e.g. proteins, peptides and plasmid DNA) for vaccines, but these antigens have been shown to be poorly immunogenic even when alum adjuvanted, implying a need for better vaccine design. In this work we review the use of natural, detoxified, or synthetic molecules in combination with antigens to activate the innate immune system and to modulate the adaptive immune responses. In the main, antigenic and imune potentiator signals are delivered using nano-, micro-particles, alum, or emulsions. The importance of interaction between adjuvants and antigens to activate and target dendritic cells, the bridge between the innate and adaptive immune systems, will be discussed. In addition, nasal vaccine strategies based on the development of mucosal adjuvants and Neisseria derivatives to eliminate the pathogen at the site of infection provide promising adjuvants effective not only against respiratory pathogens, but also against pathogens responsible for enteric and sexually transmitted diseases

Antibody-protein binding and conformational changes : identifying allosteric signalling pathways to engineer a better effector response

Numerous monoclonal antibodies have been developed successfully for the treatment of various diseases. Nevertheless, the development of biotherapeutic antibodies is complex, expensive, and time-consuming, and to facilitate this process, careful structural analysis beyond the antibody binding site is required to develop a more efficacious antibody. In this work, we focused on protein antigens, since they induce the largest antibody changes, and provide interesting cases to compare and contrast. The structures of 15 anti-protein antibodies were analysed to compare the antigen-bound/unbound forms. Surprisingly, three different classes of binding-induced changes were identified. In class (B1), the antigen binding fragment distorted significantly, and we found changes in the loop region of the heavy chain’s constant domain; this corresponds well with expected allosteric movements. In class (B2), we found changes in the same loop region without the overall distortion. In class (B3), these changes did not present, and only local changes at the complementarity determining regions were found. Consequently, structural analysis of antibodies is crucial for therapeutic development. Careful evaluation of allosteric movements must be undertaken to develop better effector responses, especially during the transformation of these antibodies from small fragments at the discovery stage to full antibodies at the subsequent development stages

The effects of hydration media on the characteristics of non-ionic surfactant vesicles (NISV) prepared by microfluidics

Non-ionic surfactant vesicles (NISV) are colloidal particles that provide a useful delivery system for drugs and vaccines. One of the methods that is used for NISV preparation is microfluidics in which the lipid components dissolved in organic phase are mixed with an aqueous medium to prepare the particles through self-assembly of the lipids. In this work, we examined the effect of using different types of aqueous media on the characteristics of the NISV prepared by microfluidics. Five aqueous media were tested: phosphate buffered saline, HEPES buffer, Tris buffer, normal saline and distilled water. The resulting particles were tested for their physical characteristics and cytotoxicity. The aqueous media were found to have significant effects on the physical characteristics of the particles, as well as their overall stability under different conditions and their cytotoxicity to different human cell lines. Careful consideration should be taken when choosing the aqueous media for preparing NISV through microfluidics. This is an important factor that will also have implications with respect to the entrapped material, but which in addition may help to design vesicles for different uses based on changing the preparation medium

Where traditional drug discovery meets modern technology in the quest for new drugs

Identifying novel compounds or improving bioavailability of drugs requires extensive screening, in vitro and in vivo testing and subsequent commercialisation. Traditional methods can be labour intensive and time-consuming. Use of modern technologies can reduce these challenges and is best achieved through collaboration with researchers specialising in different research fields. The range of research activities carried out in our lab is outlined and demonstrates the diversity of techniques used in our drug discovery programme

Cochleates derived from Vibrio cholerae O1 proteoliposomes : The impact of structure transformation on mucosal immunisation

Cochleates are phospholipid-calcium precipitates derived from the interaction of anionic lipid vesicles with divalent cations. Proteoliposomes from bacteria may also be used as a source of negatively charged components, to induce calcium-cochleate formation. In this study, proteoliposomes from V. cholerae O1 (PLc) (sized 160.7±1.6 nm) were transformed into larger (16.3±4.6 µm) cochleate-like structures (named Adjuvant Finlay Cochleate 2, AFCo2) and evaluated by electron microscopy (EM). Measurements from transmission EM (TEM) showed the structures had a similar size to that previously reported using light microscopy, while observations from scanning electron microscopy (SEM) indicated that the structures were multilayered and of cochleate-like formation. The edges of the AFCo2 structures appeared to have spaces that allowed penetration of negative stain or Ovalbumin labeled with Texas Red (OVA-TR) observed by epi-fluorescence microscopy. In addition, freeze fracture electron microscopy confirmed that the AFCo2 structures consisted of multiple overlapping layers, which corresponds to previous descriptions of cochleates. TEM also showed that small vesicles co-existed with the larger cochleate structures, and in vitro treatment with a calcium chelator caused the AFCo2 to unfold and reassemble into small proteoliposome-like structures. Using OVA as a model antigen, we demonstrated the potential loading capacity of a heterologous antigen and in vivo studies showed that with simple admixing and administration via intragastric and intranasal routes AFCo2 provided enhanced adjuvant properties compared with PLc

Delivering natural products and biotherapeutics to improve drug efficacy

Due to the increasing problem of drug resistance, new and improved medicines are required. Natural products and biotherapeutics offer a vast resource for new drugs; however, challenges, including the cost and time taken for traditional drug discovery processes and the subsequent lack of investment from the pharmaceutical industry, are associated with these areas. New techniques are producing compounds with appropriate activity at a faster rate. While the formulation of these combined with drug-delivery systems offers a promising approach for expanding the drug developments available to modern medicine. Here, various classes of drug-delivery systems are described and the advantages they bring to small molecule and biotherapeutic targeting are highlighted. This is an attractive approach to the pharmaceutical industry and the rising trend in research in this area is examined in brief

Hibiscus acid from hibiscus sabdariffa (malvaceae) has a vasorelaxant effect on the rat aorta

Hibiscus sabdariffa (Malvaceae) is a plant that is widely recognised for its antihypertensive properties; however the constituent(s) responsible for this biological activity are presently unknown. The aim of this study was to identify the potential compounds that are responsible for the vasorelaxant activity of H. sabdariffa. Thereafter, the mechanisms involved in producing the vasorelaxation were investigated. The plant was extracted consecutively with hexane, ethyl acetate and methanol. The methanolic extract was subjected to bioassay-guided fractionation in order to isolate pure compounds that possessed vasorelaxant activity. The vascular effects of the pure compounds were studied on the rat aorta in vitro using myography techniques. Hibiscus acid produced a concentration-dependent relaxation of the rat aorta pre-contracted with either phenylephrine (3 μM) or KCl (60 mM), irrespective of the presence of the endothelium. When the tissue was pre-contracted with phenylephrine, the concentration required to produce 50% relaxation (IC50), was 0.09 ± 0.01 mg/ml. Hibiscus acid had no effect on the phasic contraction induced by phenylephrine in Ca2+-free physiological solution; but it did affect the component of the contraction that is due to Ca2+ influx. In parallel studies, garcinia acid, a diastereoisomer of hibiscus acid, was found to have an almost identical vasorelaxant effect. The vasorelaxant action of both compounds is most likely due to the inhibition of Ca2+ influx via voltage-dependent Ca2+ channels

The inhibitory effect of Haloxylon salicornicum on contraction of the mouse uterus

Haloxylon salicornicum (H. salicornicum) is a plant that is frequently taken as a tea by Bedouin women in Egypt who are experiencing difficulties during pregnancy, as well as to provide relief from dysmenorrhoea. Despite its medical use, there has been no detailed evaluation of the effect of this plant on uterine tissue. Therefore, the initial aim of this study was to determine whether H. salicornicum affected the contraction of the mouse uterus in vitro. The crude aqueous extract of H. salicornicum was found to inhibit the spontaneous contractions of the uterus, with the effect being rapid in onset and completely reversible upon washout. Subsequent purification of the plant extract resulted in the identification of synephrine and Nmethyltyramine, both of which were found to have inhibitory effects on the spontaneous contractions of the uterus. The EC50 for the purified constituent identified as synephrine was 0.82 ± 0.24 g/ml. The inhibitory activity of crude H. salicornicum, as well as the isolated constituents, could be prevented by pretreatment of the uterus with the -adrenoceptor antagonist propranolol. In conclusion, the use of H. salicornicum during pre-term labour appears to be justified and its pharmacologic effect is consistent with it acting as a -adrenoceptor agonist