Intravasal contraception with styrene maleic anhydride and its noninvasive reversal in langur monkeys (Presbytis entellus entellus)

Lohiya, N. K.; Manivannan, B.; Mishra, Pradyumna Kumar; Pathak, Neelam; Balasubramanian, S.

doi:10.1016/s0010-7824(98)00073-0

Cited by 30 publications

(38 citation statements)

References 12 publications

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“…Reversal of RISUG-induced contraception has also been attempted in langur monkeys Presbytis entellus entellus , albeit, in a different way as compared to rats 6. Noninvasive reversal in langur monkeys was achieved by palpitation, percutaneous electrical stimulation and squeezing of the vas deferens, and forced vibratory movements, suprapubic percussion, and prerectal digital massage of the vas segments.…”

Section: Discussionmentioning

confidence: 99%

“…One such advancement is the development of an injectable male contraceptive, reversible inhibition of sperm under guidance (RISUG®)123 as an alternative to vasectomy, to provide safe and long-term contraception in men. RISUG, a polymeric gel consisting of styrene maleic anhydride (SMA) dissolved in dimethyl sulfoxide (DMSO), is a nonhormonal and nontoxic method of contraception with the advantage of being a nonscalpel method and ability to attain easy reversibility 1456. When injected into the vas deferens, it blocks the sperms that traverse through and destroys them by lowering the surrounding pH and creating charge disturbances in the sperm membrane 47…”

Section: Introductionmentioning

confidence: 99%

“…Following the successful demonstration of RISUG as an effective contraceptive, studies have been carried out in experimental models to evaluate its functional reversal 6121314. In langur monkeys, noninvasive reversal was achieved by percutaneous squeezing of the vas deferens, along with synchronized application of electrical stimulation, suprapubic percussion, and prerectal digital massage of the vas segments 615.…”

Section: Introductionmentioning

confidence: 99%

“…In langur monkeys, noninvasive reversal was achieved by percutaneous squeezing of the vas deferens, along with synchronized application of electrical stimulation, suprapubic percussion, and prerectal digital massage of the vas segments 615. This method of reversal, however, may not be feasible in humans due to different anatomical location of the vas deferens.…”

Section: Introductionmentioning

confidence: 99%

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Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits

et al. 2017

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The study aimed to evaluate reversal of short- and long-term vas occlusion with reversible inhibition of sperm under guidance (RISUG) using dimethyl sulfoxide (DMSO) and sodium bicarbonate (NaHCO3) in male rabbits (Oryctolagus cuniculus). Animals were divided into seven groups containing five animals each. Fortnightly, semen analysis revealed that sperm concentration and output steadily declined after vas occlusion and complete azoospermia was attained at 30–60 days postinjection. Spermatozoa reappeared at 60–75 days of reversal and normozoospermia was noticed between 135 days and 150 days in the reversal groups. All spermatozoa were found nonmotile prior to azoospermia and a gradual recovery in sperm motility was observed between 105 days and 135 days of reversal. A significant decline in viability of sperms was noticed during vas occlusion up to 30–60 days which recovered at 60–75 days postreversal and normalized by 75–105 days in the reversal groups. A significant enhancement in the sperm abnormalities was recorded in all vas occluded animals as well as those in initial periods of reversal. Other parameters, namely, semen volume, ejaculation time, pH, color, and consistency, remained unaltered during all phases of the study. Fertility test, at the intervals of 15 days, demonstrated that animals exhibited complete sterility during the entire period of vas occlusion. A gradual recovery in fertility was observed with the appearance of spermatozoa following vas occlusion reversal and 100% fertility was observed following 135–150 days of reversal. F1 progeny of reversed animals was found normal. The results suggest that reversal with DMSO or NaHCO3 is feasible, with normal progeny, following short- and long-term contraception.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits

et al. 2017

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“…Products that can be used to achieve nonsurgical sterilization of women include liquids, coils, plugs, and chemical irritants (Table 3). For males, recent alternatives to vasectomy are aimed at improved reversibility (42) and include implants and gels (Table 3) (43)(44)(45).…”

Section: Retrospectmentioning

confidence: 99%

As the world grows: contraception in the 21st century

Aitken¹,

Baker²,

Doncel³

et al. 2008

J. Clin. Invest.

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Contraceptives that are readily available and acceptable are required in many poorer countries to reduce population growth and in all countries to prevent maternal morbidity and mortality arising from unintended pregnancies. Most available methods use hormonal steroids or are variations of barrier methods. Reports from several fora over the last 12 years have emphasized the number of unwanted pregnancies and resultant abortions, which indicate an unmet need for safe, acceptable, and inexpensive contraceptive methods. This unmet need can be assuaged, in part, by development of new nonhormonal contraceptive methods. This Review addresses the contribution that the "omic" revolution can make to the identification of novel contraceptive targets, as well as the progress that has been made for different target molecules under development.

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Status of Spermatogenesis and Sperm Parameters in Langur Monkeys Following Long‐term Vas Occlusion With Styrene Maleic Anhydride

Mishra

Manivannan

Pathak

et al. 2003

Journal of Andrology

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Vas occlusion by styrene maleic anhydride (SMA), trade name RISUG (one of the promising male contraceptive procedures currently in phase III clinical trials), at 60 mg/vas deferens dissolved in 120 micro L dimethyl sulphoxide (DMSO) at up to a 540-day study period caused severe oligospermia in the first 2 to 3 ejaculations and uniform azoospermia in the subsequent ejaculations without toxicity in langur monkeys. The ejaculated spermatozoa were necroasthenoteratozoospermic, suggesting instant sterility. Routine hematology and clinical chemistry parameters and the serum testosterone and sperm antibody titers remained unchanged from their pretreatment values until 540 days vas occlusion. Histology of testes revealed continued spermatogenesis throughout the study period. The stages of spermatogenesis appeared normal until 300 days of vas occlusion. At 360 days of vas occlusion, germ cells appeared in the lumen. Degeneration of seminiferous epithelium was evident in some of the tubules. Following 420 days of vas occlusion, the central portion of the testis showed regressed seminiferous tubules depicting various shapes and devoid of germ cells, which continued until 540 days of vas occlusion. Ultrastructure of the testes after 540 days of vas occlusion revealed vacuolization in the cytoplasm of Sertoli cells and degenerative features in the membranes of the spermatocytes and spermatids in the affected seminiferous tubules. The sub-cellular features of the normal tubules were similar to those of controls. The results suggest focal degeneration of seminiferous epithelium in the central portion of the testis following long-term vas occlusion with SMA.

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Intravasal contraception with styrene maleic anhydride and its noninvasive reversal in langur monkeys (Presbytis entellus entellus)

Cited by 30 publications

References 12 publications

Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits

Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits

As the world grows: contraception in the 21st century

Status of Spermatogenesis and Sperm Parameters in Langur Monkeys Following Long‐term Vas Occlusion With Styrene Maleic Anhydride

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Intravasal contraception with styrene maleic anhydride and its noninvasive reversal in langur monkeys (Presbytis entellus entellus)

Cited by 30 publications

References 12 publications

Contraception with RISUG® and functional reversal through DMSO and NaHCO3 in male rabbits

Contraception with RISUG® and functional reversal through DMSO and NaHCO3 in male rabbits

As the world grows: contraception in the 21st century

Status of Spermatogenesis and Sperm Parameters in Langur Monkeys Following Long‐term Vas Occlusion With Styrene Maleic Anhydride

Contact Info

Product

Resources

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Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits

Contraception with RISUG^® and functional reversal through DMSO and NaHCO₃ in male rabbits