Dataset Information

Designed Chemical Intervention with Thiols for Prophylactic Contraception.

ABSTRACT: Unlike somatic cells, sperm have several-fold more available-thiols that are susceptible to redox-active agents. The present study explains the mechanism behind the instant sperm-immobilizing and trichomonacidal activities of pyrrolidinium pyrrolidine-1-carbodithioate (PPC), a novel thiol agent rationally created for prophylactic contraception by minor chemical modifications of some known thiol drugs. PPC, and its three derivatives (with potential active-site blocked by alkylation), were synthesized and evaluated against live human sperm and metronidazole-susceptible and resistant Trichomonas vaginalis, in vitro. Sperm hexokinase activity was evaluated by coupled enzyme assay. PPC irreversibly immobilized 100% human sperm in ∼30 seconds and totally eliminated Trichomonas vaginalis more efficiently than nonoxynol-9 and metronidazole. It significantly inhibited (P<0.001) thiol-sensitive sperm hexokinase. However, the molecule completely lost all its biological activities once its thiol group was blocked by alkylation. PPC was subsequently formulated into a mucoadhesive vaginal film using GRaS excipients and evaluated for spermicidal and microbicidal activities (in vitro), and contraceptive efficacy in rabbits. PPC remained fully active in quick-dissolving, mucoadhesive vaginal-film formulation, and these PPC-films significantly reduced pregnancy and fertility rates in rabbits. The films released ∼90% of PPC in simulated vaginal fluid (pH 4.2) at 37°C in 5 minutes, in vitro. We have thus discovered a common target (reactive thiols) on chiefly-anaerobic, redox-sensitive cells like sperm and Trichomonas, which is susceptible to designed chemical interference for prophylactic contraception. The active thiol in PPC inactivates sperm and Trichomonas via interference with crucial sulfhydryl-disulfide based reactions, e.g. hexokinase activation in human sperm. In comparison to non-specific surfactant action of OTC spermicide nonoxynol-9, the action of thiol-active PPC is apparently much more specific, potent and safe. PPC presents a proof-of-concept for prophylactic contraception via manipulation of thiols in vagina for selective targeting of sperm and Trichomonas, and qualifies as a promising lead for the development of dually protective vaginal-contraceptive.

SUBMITTER: Sharma M

PROVIDER: S-EPMC3694959 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:In a context of high rates of HIV prevalence, concerns over hormonal contraceptive use and the potential for increased risk of HIV acquisition have led to increased attention to counseling messages, particularly for users of the injectable. However, the consequence of adding additional HIV risk messages to family planning counseling sessions was not well understood. This evaluation assessed the effect of providing revised injectable and HIV risk counseling messages on contraceptive knowledge and behavior during a three month pilot intervention. The pilot intervention was conducted September-November 2018 with all eligible family planning clients in ten healthcare facilities located in the Iringa and Njombe regions of Tanzania. Data collection for the evaluation occurred November-December 2018 and included 471 client exit interviews, 26 healthcare provider interviews, and the extraction of service statistics for 12 months prior to the intervention and three months of the intervention. Univariate and bivariate analyses were used to assess quantitative interview data. Thematic qualitative assessment was used to assess qualitative interview data from healthcare providers. Interrupted time series analysis was used to assess changes in the trend of contraceptive uptake. Results indicate that the counseling messages did not cause a decrease in the uptake of injectables (Depo-Provera): 97 percent of interviewed clients received Depo-Provera at their visit; sixty percent reported an intention to use condoms for dual protection. The analysis of service statistics showed no statistical difference in the trend of Depo-Provera uptake between the pre-intervention and intervention periods (p = 0.116). Overall knowledge of counseling messages by clients was good; however only 64.8% of women correctly responded that women at risk of getting HIV can use any method of family planning. Providers' knowledge of the messages was high, though it appears that not all messages were consistently provided during the counseling sessions. The findings from this evaluation provide evidence that complex HIV counseling messages can be implemented in family planning programs in Tanzania, and potentially in other countries that are considering how to better integrate HIV risk messages into family planning counseling.

Dataset Information

Designed Chemical Intervention with Thiols for Prophylactic Contraception.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets