Blockade of tubal patency following transcervical administration of polidocanol foam: initial studies in rhesus macaques

Systemic polidocanol from intravenous or pressurized intrauterine administration produces reversible cardiovascular toxicity

Objective

Fatal allergic responses and cardiac arrhythmias have been reported with the intravenous (IV) administration of polidocanol. We sought to identify the physiologic mechanism of systemic cardiovascular response after transcervical (TC) and IV administration of polidocanol.

Methods

We continuously monitored blood pressure (BP) and heart rate using an arterial line during IV and intraperitoneal (IP) administration of polidocanol solution (PS) and polidocanol doxycycline solution in female rats and TC and IP administration of polidocanol foam (PF) and PDF (TC only) in female baboons. We performed TC procedures using a catheter with (pressurized) and without (nonpressurized) balloon inflation. Baboons also underwent monitoring during IV PS administration with and without pretreatment with antihistamines. We performed cardiac echo and electrocardiograms during selected experiments. We defined a refractory hypotension as a sustained decrease of more than 30% from baseline that prevented delivery of the target dose.

Results

We found a dose-related increase in the proportion of baboons that developed refractory hypotension during TC administration of 5% PDF and PF, an effect confined to pressurized administration. The infusion of 0.5% PS in rats induced a rapid and dramatic refractory hypotension. The inclusion of doxycycline did not improve or deteriorate these outcomes, and doxycycline solution or saline (control) alone did not affect BP. All five female baboons that received up to 20 mL of 1% PS (200 mg) developed refractory hypotension. Pretreatment with diphenhydramine, ranitidine, or both did not block the refractory hypotension induced by IV administration of 1% PS (100 mg). In contrast, only one of the six female baboons treated with IP PF 400 mg developed a decrease of more than 30% in BP, and this response was not sustained. Cardiac echocardiography done in four baboons during TC treatment demonstrated a decrease in cardiac output as the physiologic mechanism of hypotension. We did not observe important changes on the electrocardiograms.

Conclusions

Adverse cardiovascular effects of polidocanol treatment occur owing to a direct myocardial effect of polidocanol and not as a result of a hypersensitivity reaction. Pressurized TC administration of PF results in refractory hypotension owing to endometrial vascular uptake of polidocanol and not as a result of uptake from peritoneal surfaces.

Effect of tissue microenvironment on fibrous capsule formation to biomaterial-coated implants

Within tissue exposed to the systemic immune system, lymphocytes and fibroblasts act against biomaterials via the development of a fibrous capsule, known as the foreign body reaction (FBR). Inspired by the natural tolerance that the uterine cavity has to foreign bodies, our study explores the role of microenvironment across classical (subcutaneous) and immune privileged (uterine) tissues in the development of the FBR. As a model biomaterial, we used electrospun fibers loaded with sclerosing agents to provoke scar tissue growth. Additionally, we integrated these materials onto an intrauterine device as a platform for intrauterine biomaterial studies. Polyester materials in vitro achieved drug release up to 10 days, greater pro-inflammatory and pro-healing cytokine expression, and the addition of gelatin enabled greater fibroblast attachment. We observed the materials that induced the greatest FBR in the mouse, had no effect when inserted at the utero-tubal junction of non-human primates. These results suggest that the FBR varies across different tissue microenvironments, and a dampened fibrotic response exists in the uterine cavity, possibly due to immune privilege. Further study of immune privileged tissue factors on biomaterials could broaden our understanding of the FBR and inform new methods for achieving biocompatibility in vivo.

Ketamine Use in Hysterosalpingography (the Jimah Procedure): A Follow-Up of Bilateral Tubal Evaluation of 27 Infertile Women at a Teaching Hospital, Ghana

Background

Pain, anxiety, and distress are common in radiological investigations including hysterosalpingogram (HSG). Studies suggest that sedation allows patients to better tolerate diagnostic imaging and image-guided procedures by relieving anxiety, discomfort, and pain. This study aimed at assessing the safety and effectiveness of ketamine use in HSG and the proportion of true positive bilateral tubal blockage during HSG using the Jimah Procedure.

Methods

We performed repeated HSG workup under IV ketamine (20–40 mg/mL) sedation for 27 infertile women at the Cape Coast Teaching Hospital. The exclusion criteria included unilateral tubular blockage, acute infection of the vagina or cervix, active vaginal bleeding, glaucoma, and high blood pressure at the time of the study. Data were entered with Microsoft Excel and analyzed using SPSS version 21.

Results

A total of 27 patients (age range: 25–48 years) previously diagnosed of bilateral tubal blockage or spasm were enrolled for the repeat HSG procedure. The median age was 34 years (IQR: 32–37), while secondary infertility (20) (74.1%) was the commonest indication. None of the patients reported of pain or distress during or after the procedure. Two (7.4%) women vomited after HSG. Twelve patients (44.4%) had bilateral tubal blockage (true positive), while tubal patency was seen in 15 (55.6%) patients on HSG under ketamine sedation.

Conclusion

This study found IV ketamine sedation produces profound anesthesia and analgesia and eliminates tubal spasm. We recommend that radiologists in developing countries should consider sedating patients during HSG and documenting observations and patients' feedback to help assess safety and effectiveness in local settings.

A novel technology for reversible fallopian tubal occlusion using a reverse thermo-responsive polymer-Preliminary results from a rabbit animal study

OBJECTIVES

To determine if PF-88, a reverse thermo-responsive polymer designed to create a gel at body temperature and liquefy at a lower temperature (21°C) can reversibly occlude the fallopian tubes in rabbits.

STUDY DESIGN

Mature female New Zealand White rabbits underwent laparotomy and placement of 22-gage catheter into the lumen of the distil uterine horns for evaluation of tubal patency by fluoroscopy using radio opaque contrast and treatment with PF-88. In the Acute Phase group (n = 5) after PF-88 treatment we immediately cooled the serosal surface of the tube with ice for 90 seconds to liquify the gel then reassessed patency. In the Survival Phase groups, animals recovered from the initial surgery and then underwent a second procedure for evaluation of tubal occlusion and reversibility at 4 (n = 3), 14 (n = 2), and 28 (n = 3) weeks after the initial procedure. We compared the histologic appearance of the treated fallopian tubes to untreated controls (n = 3).

RESULTS

In the Acute Phase, we found all 10 fallopian tubes patent on initial evaluation, occluded following treatment with PF88, and patent following re-liquification by chilling. Animals in the Survival Group, all but one of the treated tubes appeared blocked at follow-up and patent following chilling. The treatment failure occurred in an animal in the 4-week group. Tubes treated with PF88 showed no histologic evidence of residual material or damage after removal of the polymer.

CONCLUSION

The PF-88 reverse thermo-responsive polymer demonstrated the ability to reversibly block fallopian tubes for up to 28 weeks.

IMPLICATIONS

The demonstration of reversible occlusion of the fallopian tube of rabbits using PF-88, a thermo-responsive reverse polymer, support additional studies to evaluate the potential of this polymer as a contraceptive in women.

Reversible inhibition of sperm under guidance as an intratubular and reversible contraception in female rats: An experimental study

Background

Reversible inhibition of sperm under guidance (“RISUGⓇ”) is a promising intravasal male contraceptive.

Objective

An exploratory study was conducted with a concept of non-invasive, transcervical, single-intervention and reversible contraception using RISUGⓇ in females.

Materials and Methods

In this experimental study, 60 adult Wistar albino female rats weighing 150-155 g, 3-4 months old were divided into four groups: group I: sham-operated control; group II: tubal occlusion with RISUG for 90 days; group III: tubal occlusion with RISUGⓇ for 90 days and reversal with dimethyl sulphoxide and group IV: tubal occlusion with RISUGⓇ for 90 days and reversal with 5% NaHCO. Animals were subjected to bilateral fallopian tube occlusion with RISUGⓇ and reversal with DMSO and NaHCO3. The estrous cycle, fertility and histology of fallopian tube were evaluated.

Results

Group I showed 100% fertility during all mating schedules. Animals of experimental groups indicated positive mating, but 0% fertility was evident following 30, 60, and 90 days of tubal occlusion. However, after reversal, fertility steadily increased to normalcy in groups III (50% at 45 days, 80% at 105 days, 100% at 150 and 195 days) and IV (70% at 45 and 105 days, 100% at 150 and 195 days) animals. Group II illustrated disorganized inner cell linings and eosinated RISUGⓇimplant-filled lumen. Reversal groups (III and IV) revealed complete restoration of cellular histo-architecture. Regular estrous cycle was noticed in all experimental groups.

Conclusion

RISUGⓇ is suitable for single intervention, intratubular, reversible contraception in female rats.

Intrauterine fluid instillation to confirm tubal occlusion after transcervical permanent contraception: A pilot study

OBJECTIVES

To determine if women with tubal patency experience more fluid loss compared to those with bilateral tubal occlusion following intrauterine instillation of fluid via a balloon catheter.

STUDY DESIGN

In this prospective cohort pilot study, we enrolled women with prior Essure® procedures and healthy controls from September 2016 to July 2017. We excluded women using an implant or intrauterine device, or with a prior cesarean delivery or permanent contraception procedures other than Essure®. An infusion pump delivered saline via balloon catheter under continuous pressure monitoring. After one minute, we withdrew the fluid and recorded volumes in and out. Subjects then underwent hysterosalpingogram for evaluation of tubal patency. We conducted crude analyses with t-tests and sensitivity analyses.

RESULTS

We recruited 23 participants; ten provided analyzable data in each group. Hysterosalpingogram confirmed patency in all control and occlusion in all post-Essure® subjects in the analysis group. We found the median volume of saline lost among control subjects [7.8 mL (7.4, 8.4)] larger than post-Essure® participants [2.2 mL (2.0, 3.8), p < 0.01]. While 50% of control subjects tolerated the full 10 mL of fluid instillation, none of the post-Essure® subjects tolerated this volume (p = 0.03). A combination of saline loss ≤4 mL and participant intolerance of the full 10 mL volume yielded sensitivity of 0.80 (95% CI: 0.57, 1.00) and specificity of 1.00 for bilateral tubal occlusion.

CONCLUSION

Instillation of a fixed volume into the uterus may discriminate between women with tubal patency and occlusion following permanent contraception procedures with high specificity and adequate sensitivity. These findings should be validated in larger, more diverse study populations.

IMPLICATIONS

Confirmation of tubal occlusion following permanent contraception with an office-based approach could improve acceptability of transcervical approaches. The recent removal of Essure® from the U.S. market increases the need for novel transcervical procedures and occlusion verification methods.

Pressure dynamics in the non-gravid uterus: intrauterine pressure cannot confirm tubal occlusion after non-surgical permanent contraception

OBJECTIVE

The objective was to determine if intrauterine pressure can distinguish bilateral tubal occlusion (BTO) from unilateral or bilateral tubal patency (TP) in women following a permanent contraception procedure.

STUDY DESIGN

We used a small inline pressure sensor to continuously monitor intrauterine pressure during hysterosalpingogram (HSG) in a cross-sectional study that enrolled women having HSGs for any indication. The primary outcome was the peak intrauterine pressure compared between women with BTO and TP as verified by HSG.

RESULTS

We enrolled 150 subjects, of which 111 (74.0%) provided usable pressure readings. Of these, 98/111 (88.3%) had TP, and 13 (11.7%) had BTO. There was no difference in peak intrauterine pressure for subjects with TP (mean 293.8±58.7 mmHg) compared to those with BTO (292.7±71.3 mmHg, p=.95). Among parous women, peak intrauterine pressure in subjects with BTO (311.9±78.0 mmHg) was higher but not significantly different from subjects with TP (282.7±49.2 mmHg, p=.20). In linear regression analysis, peak intrauterine pressure was not associated with age, body mass index, gravidity or having at least one prior live birth.

CONCLUSIONS

Measurement of peak intrauterine pressure does not distinguish between women with patent and blocked fallopian tubes. This approach would not be clinically useful to verify occlusion following permanent contraception.

IMPLICATIONS

Peak intrauterine pressure does not differ between women with patent and occluded fallopian tubes and cannot be used to confirm tubal occlusion after nonsurgical permanent contraception.

Transcervical administration of polidocanol foam prevents pregnancy in female baboons

Background

Our objective was to conduct a pilot study to determine if transcervical administration of polidocanol foam (PF) with or without doxycycline or benzalkonium chloride (BZK) would prevent pregnancy in baboons.

Methods

In study phase 1, adult cycling baboons underwent a hysterosalpingogram to evaluate tubal patency prior to transcervical infusion of 20 mL of 5% PF followed by 1 mL of saline containing 100 mg doxycycline (5%/doxy; n=5), 3% PF plus doxycycline (3%/doxy; n=4), 3% PF with 0.01% BZK (3%/BZK; n=4) or no additional treatment (control; n=9). Immediately following treatment, animals received intramuscular depot medroxyprogesterone acetate (DMPA, 2 mg/kg) to suppress cyclicity during healing and were then socially housed with males of proven fertility. The primary outcome was pregnancy within six cycles of resumption of menses (efficacy phase 1). During study phase 2, PF-treated females from study phase 1 contributed additional cycles (6–8) of exposure (efficacy phase 2), and 5 control females who had recovered from medical abortion (after study phase 1 pregnancy) were subsequently treated with 5% PF (with DMPA) and exposed to breeding (efficacy phase 1; n=3 six cycles, n=2 five cycles).

Results

All females resumed normal menstrual cycles and mating activity after DMPA. During efficacy phase 1, 7/9 (78%) control females became pregnant. In contrast, fewer pregnancies occurred in PF-treated females: 5% PF 0/5 (0%), 5%/doxy 1/5 (20%), 3%/doxy 1/4 (25%) and 3%/BZK 1/4 (25%). During efficacy phase 2, only one additional pregnancy occurred (3%/BZK).

Conclusions

A single transcervical treatment with 5% PF prevented pregnancy in most baboons. Cotreatment with doxycycline or BZK did not improve results.

Implications

Transcervical intrauterine administration of PF resulted in a high rate of tubal occlusion with prevention of pregnancy; refinements are needed to increase the contraceptive rate following a single treatment to near 100%.

Polidocanol induced tubal occlusion in nonhuman primates: immunohistochemical detection of collagen I-V

OBJECTIVE

Intrauterine administration of polidocanol foam (PF) can create fallopian tube occlusion in nonhuman primates. The objective of this study was to determine if PF-induced tubal obstructions contain collagen in the extracellular matrix.

STUDY DESIGN

We compared tissue samples of the intramural fallopian tube obtained from previous studies evaluating the effects of intrauterine infusion of 5% PF 2-12 weeks after treatment. Serial sections of the intramural portion of the fallopian tube obtained from representative treated (rhesus macaques, n=7; baboon, n=11) and untreated control (macaque, n=3; baboon, n=5) animals were stained with hematoxylin and eosin to identify tubal occlusion and by immunohistochemistry for collagens Col-I, Col-III and Col-IV. Descriptive results are summarized.

RESULTS

Control animals exhibited histologically normal fallopian tubal epithelium with no staining for Col-1, light staining for Col-III and Col-V in the lamina propria and Col-IV distributed evenly in the extracellular matrix of the lamina propria. Treatment with PF resulted in acute tissue damage confined to the intramural tube; no epithelial damage or occlusion occurred in the tubal isthmus or ampulla. Blockade of the intramural tube demonstrated fibrosis with the epithelium replaced with extracellular matrix that stained strongly for Col-I, Col-III, Col-IV and Col-V. Col-II was undetectable.

CONCLUSION

Tubal blockage induced by PF resulted in loss of normal epithelium and accumulation of collagens Col-I, Col-III, Col-IV and Col-V at the site of obstruction. The presence of dense collagen staining supports the hypothesis that PF infusion creates lasting tubal obstructions.

IMPLICATIONS

This study demonstrates that PF-induced tubal occlusion results in deposition of collagens suggesting the potential for a more lasting blockade. The structural nature of this occlusion supports the development of intrauterine administration of PF as a nonsurgical method of permanent contraception.

Update on permanent contraception options for women

PURPOSE OF REVIEW

Permanent methods are the most commonly used contraceptive options worldwide. Even with the increase in popularity and accessibility of long-acting reversible methods, there remains high demand for permanent options, especially among women in developing countries.

RECENT FINDINGS

Traditional methods of permanent contraception, such as postpartum tubal ligation and interval surgical tubal occlusion or electrocautery by mini-laparotomy or laparoscopy are well tolerated and highly effective. Bilateral total salpingectomy for ovarian cancer risk reduction is currently being investigated. Hysteroscopic tubal occlusion reduces or eliminates the need for anesthesia, but requires surgical training and specialized equipment. Alternative permanent contraception methods are being explored including immediately effective hysteroscopic methods, and nonsurgical permanent contraception methods that have the potential to improve access and reduce cost.

SUMMARY

Permanent contraception methods are an important part of the contraceptive methods mix designed to meet the needs of women who have completed desired family size or wish never to become pregnant. Current surgical approaches to permanent contraception are well tolerated and highly effective. The development of a highly effective nonsurgical approach could simplify the provision of permanent contraception.

Improvement of stability of polidocanol foam for nonsurgical permanent contraception

BACKGROUND

Polidocanol foam (PF), used clinically as a venous sclerosant, has recently been studied as a safe and inexpensive means for permanent contraception. Delivering the sclerosant to the fallopian tubes as a foam rather than a liquid increases the surface areas and thus enhances the desired epithelial disrupting activity of the agent. However, the foam is inherently unstable and degrades with time. Therefore, increasing foam stability and thus duration of the agent exposure time could increase epithelial effect while allowing reduction in agent concentration and potential toxicity.

MATERIALS AND METHODS

We studied methods to improve foam properties that might improve safety and efficacy of PF for intrauterine application. Several types of microporous filters adapted to a syringe-based foaming device were used to study the effect of pore structures on the formation of PF. The foam drainage time and bubble size were characterized. The addition of benzalkonium chloride (BZK) to polidocanol was also investigated for its effects on foam characteristics.

RESULTS

A syringe-based foaming device adapted with an inline filter produced smaller bubble PF with a longer foam drainage time. PF generated with a circular pore filter lasts longer than with a noncircular pore filter. The addition of 0.01% of BZK also improved the stability of PF.

CONCLUSION

The stability of PF is affected by the pore characteristics of the filter used for foam generation and enhanced by the presence of a small amount of BZK. The improved foam, if shown to be efficacious in animal models of contraception, could lead to a safe, simple and inexpensive method alternative to surgical contraception.

Characterization of tubal occlusion after transcervical polidocanol foam (PF) infusion in baboons

OBJECTIVE

Our long-term goal is to develop a nonsurgical method of fallopian tubal occlusion for the purpose of permanent contraception. We have previously demonstrated that transcervical administration of 5% polidocanol foam (PF) can create tubal occlusion in macaques but that multiple treatments are required. In this study, we assessed the efficacy of various regimens of PF with and without depomedroxyprogesterone acetate (DMPA) (to control ovarian cycle phase) in the baboon.

STUDY DESIGN

Adult cycling female baboons were evaluated for tubal patency by hysterosalpingography and then received a transcervical infusion of PF with (+) or without (-) an intramuscular injection of DMPA (3.5 mg/kg). Two concentrations of PF were compared: 1% [(+) DMPA, n=5; (-) DMPA, n=3] and 5% [(+) DMPA, n=4; (-) DMPA, n=3]. Controls received (+) DMPA (n=2) or (-) DMPA, (n=3) only. The reproductive tracts were removed 1-3 months after treatment for examination.

RESULTS

No fallopian tubal occlusion was observed in negative controls (±DMPA). Histologic complete tubal occlusion was observed in 3/8 of females treated with 1% PF and in 6/7 treated with 5% PF. Histologic evaluation suggested that 1% PF is associated with prolonged chronic inflammation (more than 2-3 months), while 5% treatment eliminates the epithelial lining, at least focally, and resolves into complete occlusion within 1-2 months. This pattern of complete occlusion was seen in all 4 females that received 5% PF (+DMPA) and in 2/3 that received 5% PF (-DMPA).

CONCLUSION

In a baboon model of transcervical permanent contraception, a single treatment with 5% PF resulted in complete tubal occlusion more reliably (85%) than 1% PF (38%). Cotreatment with DMPA may improve treatment results with 5% PF but requires additional study.

IMPLICATIONS

A finding that a single transcervical treatment with 5% PF can occlude the fallopian tubes of baboon supports further study of this approach as a novel strategy for permanent contraception for women.

Animal models of contraception: utility and limitations

Appropriate animal modeling is vital for the successful development of novel contraceptive devices. Advances in reproductive biology have identified novel pathways for contraceptive intervention. Here we review species-specific anatomic and physiologic considerations impacting preclinical contraceptive testing, including efficacy testing, mechanistic studies, device design, and modeling off-target effects. Emphasis is placed on the use of nonhuman primate models in contraceptive device development.

Interest in nonsurgical female permanent contraception among men in Portland, Oregon and eastern Maharashtra, India

OBJECTIVE

We examined the men's attitudes and perceptions toward the concept of female nonsurgical permanent contraception (NSPC) or novel approaches to permanent contraception (PC) that do not require incisions or surgical equipment/hysteroscope.

STUDY DESIGN

Cross-sectional survey of married/partnered men in Portland, OR, and rural eastern Maharashtra, India. Descriptive analysis was performed.

RESULTS

In India (N=150), most men (80%) anticipated that their partners would undergo PC in the future, compared to 30% in Portland (N=170). About a third (39.6% in India, 82% in Portland) reported being uncomfortable with PC for partners due to the need for surgery. Most men (85% in India, 82% in Portland) expressed a preference for a hypothetical new method of female NSPC over surgery, if safe and effective.

CONCLUSION

Most men sampled in two diverse settings expressed interest in NSPC for women.

IMPLICATIONS

Men's perceptions of new female contraceptive methods are important to the contraceptive development process. Men may find a safe and effective nonsurgical method of permanent female contraception more acceptable than surgical PC.

The history and current status of fallopian tube pressures - developing alternate methods for confirmation of tubal occlusion

Permanent contraception with hysteroscopic tubal ligation is an increasingly popular choice for women around the world. However, inconveniences associated with the required confirmation test for tubal occlusion can be prohibitive. As new methods of permanent contraception are being investigated, ways of making all aspects of the procedure more accessible and comfortable for women should be considered. Means of examining tubal patency in the infertility population, such as tubal perfusion pressures measured at the time of hysterosalpingogram (HSG), provide inspiration for alternative methods of tubal occlusion confirmation after contraception. Evaluation of intrauterine pressures measured by a manometer attached to an intrauterine balloon catheter could serve as a preliminary tool for verification of tubal occlusion; higher pressures would indicate tubal occlusion and lower pressures would indicate the need for confirmatory HSG. The development and validation of this technique is ongoing and could reduce overall costs and patient burdens associated with the current tubal occlusion confirmation procedure.

Applying emerging science to contraception research: implications for the clinic

Emerging science will make an important contribution towards the development of improved contraceptives. While long-acting reversible contraceptives remain the most effective method, new user-controlled, mid-acting methods will avoid the need for procedures requiring trained providers. Contraceptives combined with other agents may bring additional health benefits, such as dual protection against both pregnancy and sexually transmitted infections. Emerging research areas in proteomics allowed the discovery of new reproductive targets that may lead to non-hormonal contraceptives for both men and women. Current research objectives include the improvement of existing contraceptive methods, as well as discovery of new materials able to deliver new molecules more specifically to their target without systemic actions.