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

Immunization of Female Mice with a Plasmid DNA Vaccine Coding EightRepeats of Gonadotrophin Releasing Hormone (Gnrh-I) and Eight T-HelperEpitopes Suppress Fertility In Vivo

Induction of an appropriate immune response against gonadotrophin releasing hormone (GnRH-I) disrupt fertility,reduce fecundity and regress tumours of reproductive system.To disrupt fertility a plasmid DNA vaccine wasengineered coding eight repeats of GnRH-I and eight T-helper epitopes. Translation efficiency of the vaccine wasevaluated in undifferentiated COS1 cells and found to release GnRH-I fusion protein in culture supernatant. Swissalbino female mice (N=24) were immunized with 50μg plasmid DNA construct in study weeks 0, 3, 6, 9 and 12.Group 2 mice were primed with the plasmid DNA in hemagglutinating virus of japanese envelope (HVJE) vector andsubsequent boosts were carried out in phosphate buffer saline. Group 3 mice were immunized with the plasmid DNAin non-ionic surfactant vesicles (NISV) and Group 1 was served as untreated control. The effect of immunization wasstudied in terms of anti-GnRH-I antibody response (OD value at A540 ± SD), suppression of ovarian folliculogenesis,altered uterine histoarchitecture and impaired fertility in vivo in mating trials. In study week 24 OD values of anti-GnRH-I antibody response were 0.982 ± 0.231 in Group 3 mice, followed by 0.783 ± 0.191 in Group 2 in comparisonwith no response in Group 1 controls (0.237 ± 0.147). Results of mating trials showed conception failure invaccinated mice; 51, 18 and 05 pups were seen in the uteri of Groups 1, 2 and 3 mice respectively. There wassignificant (p>0.001) reduction in the weight of ovaries in Group 2 (8.50 ± 2.38 mg) and Group 3 (7.25 ± 0.95 mg)mice compared to Group 1 control (15.00 ± 1.41 mg). Significant reduction of ovarian folliculogenesis was seen inGroup 2 (p>0.001) and Group 3 mice (p>0.01). In conclusion, the plasmid DNA vaccine delivered in female micewith HVJE and NISV induced significantly (p>0.001) higher levels of anti-GnRH-I antibody response, suppressedovarian and uterine function and impaired fertility in vivo

Comparison of the physical characteristics of monodisperse non-ionic surfactant vesicles (NISV) prepared using different manufacturing methods

Non-ionic surfactant vesicles (NISV) are synthetic membrane vesicles formed by self-assembly of a non-ionic surfactant, often in a mixture with cholesterol and a charged chemical species. Different methods can be used to manufacture NISV, with the majority of these requiring bulk mixing of two phases. This mixing process is time-consuming and leads to the preparation of large and highly dispersed vesicles, which affects the consistency of the final product and could hinder subsequent regulatory approval. In this study, we have compared the physical characteristics of NISV prepared using two conventional methods (thin-film hydration method and heating method) with a recently introduced microfluidic method. The resulting particles from these methods were assessed for their physical characteristics and in vitro cytotoxicity. Through microfluidics, nano-sized NISV were prepared in seconds, through rapid and controlled mixing of two miscible phases (lipids dissolved in alcohol and an aqueous medium) in a microchannel, without the need of a size reduction step, as required for the conventional methods. Stability studies over two months showed the particles were stable regardless of the method of preparation and there were no differences in terms of EC50 on A375 and A2780 cell lines. However, this work demonstrates the flexibility and ease of applying lab-on-chip microfluidics for the preparation of NISV that could be used to significantly improve formulation research and development, by enabling the rapid manufacture of a consistent end-product, under controlled conditions

Optimizing efficacy of mucosal vaccines

In general, there are only a few vaccines administered via mucosal routes, as the mucosal immune system presents numerous hurdles, including diversity in mucosal surface structure, complexity in immune cell interaction and limitations in experimental methodology. This therefore necessitates a range of strategies to be used for each target area. With reference to the three main routes of delivery and associated mucosal surfaces (oral/intestinal, nasal/respiratory and female genital tract), this review examines how coadministration of immune-stimulatory molecules, adjuvants, delivery systems and mucoadhesives are used to improve mucosal vaccine efficacy. Key considerations to the development of next-generation mucosal vaccines include improved efficacy and safety, technological advancements in medical devices to enable convenience and better administration, as well as reduced manufacturing costs

Assessment of the antigen-specific antibody response induced by mucosal administration of a GnRH conjugate entrapped in lipid nanoparticles

Vaccines administered parenterally have been developed against gonadotrophin releasing hormone (GnRH) for anti-fertility and anti-cancer purposes. The aim of this study was to demonstrate whether mucosal delivery using GnRH immunogens entrapped in lipid nanoparticles (LNP) could induce anti-GnRH antibody titres. Immunogens consisting of KLH (keyhole limpet haemocyanin) conjugated to either GnRH-I or GnRH-III analogues were entrapped in LNP. Loaded non-ionic surfactant vesicles (NISV) were administered subcutaneously, while nasal delivery was achieved using NISV in xanthan gum and oral delivery using NISV containing deoxycholate (bilosomes). NISV and bilosomes had similar properties: they were spherical, in the nanometre size range, with a slightly negative zeta potential and surface properties that changed with protein loading and inclusion of xanthan gum. Following immunisation in female BALB/c mice, systemic antibody responses were similar for both GnRH-I and GnRH-III immunisation. Only nasal delivery proved to be successful in terms of producing systemic and mucosal antibodies

An update on developments in female hormonal contraception

The human population continues to grow in some parts of the world, which has severe impact on resources, health and the environment. Individually, contraception enables women to choose their optimal family size and birth spacing, while in resource-poor countries it can help lift families out of poverty. While the oral contraceptive pill revolutionised female contraceptive options, there was a price to pay in terms of increased health risks. Today, improved formulations have been developed, together with non-oral hormonal technologies. This review will examine the history of female contraceptive research and provide an update on the status and future direction of new products

Mucosal and systemic immune responses following mucosal immunisation of tetanus toxoid entrapped in lipid nanoparticles prepared by microwave reactor

In this study, the use of a microwave reactor, which allowed high input of energy into a pressurised system in a short period of time, was investigated for preparation of lipid nanoparticles (LNPs). The aim was to optimise the formulation process by reducing manufacturing time. Two types of LNPs were prepared; non-ionic surfactant vesicles (NISV) and bilosomes (modified NISV incorporating bile salts), with a model antigen (tetanus toxoid, TT) and the immune response induced after mucosal (nasal and oral, respectively) administration was assessed. The TT loaded LNPs were characterised in terms of particle size, size distribution, morphology, and entrapment efficiency. Immunisation was evaluated by lethal challenge with tetanus toxin in an animal model. The efficiency of vaccination was evaluated by measuring the anti-TT IgG antibody levels in the vaccinated animals. Bilosomes formed by this method showed an immunogen entrapment efficiency of ∼ 30% which was significantly (

Evaluation of immunocastration conjugates based on GnRH linked to carrier molecules in a male rodent model

Gonadotropin-releasing hormone (GnRH) stimulates the pituitary gland to secrete sex hormones. In the present study, we evaluated different conjugates of GnRH to abrogate sex hormone secretion in a male rat model. Firstly, GnRH-I was conjugated to keyhole limpet haemocyanin (KLH) using either whole-sequence GnRH-I or an analogue of GnRH-I (CHWSYGLRPG-NH2) using glutaraldehyde cross linkage. Six-week-old Sprague-Dawley male rats (n=6) were immunized intramuscularly with the conjugates adsorbed onto alum, equivalent to 50 μg of GnRH peptide and administered in weeks 1, 3, 5 and 7. The study was concluded in week 15. Comparison was made with untreated controls and previously established anti-fertility conjugates: CHWSYGLRPG-NH2 (GnRH-I) or CHWSHDWKPG-NH2 (analogue of lamprey GnRH-III, lGnRH-III) linked to tetanus toxoid (using a heterobifunctional reagent to achieve cross linkage). Antibody production, hormone levels and testicular diameter changes were assessed, together with, sperm movement and effects on organ weights. Similar high levels of antibody secretion were observed in all the immunized groups, although whole GnRHI- KLH produced a sustained level of production for an additional week. Similarly, testosterone levels were significantly (p<0.05) reduced in all immunized groups. There were no significant changes observed in body weight and testicular diameter of immunized animals compared with the untreated controls. However, in terms of sperm motility and sperm number, the best anti-fertility effects were observed with lGnRH-III-TT and GnRH-I-KLH and to a lesser extent whole GnRH-I-KLH. These groups also showed significant increase in kidney weight. Finally, considering all the above-mentioned subjects in addition to availability and easier and cheaper way of preparation,we came to this conclusion that whole GnRH-IKLH satisfactorily met most of our favourite criteria and could be used in immunocastration vaccine production purposes successfully