Local tissue effects of copper-containing intrauterine devices

Feasibility evaluation of a Cu-38 Zn alloy for intrauterine devices: In vitro and in vivo studies

The existing adverse effects of copper in copper-containing intrauterine devices (Cu-IUDs) have raised concerns regarding their use. These adverse effects include burst release of cupric ions (Cu²⁺) at the initial stage and an increasingly rough surface of the Cu-IUDs. In this study, we investigated the use of two copper alloys, Cu-38 Zn and H62 as the new upgrading or alternative material for IUDs. Their corrosive properties were studied in simulated uterine fluid (SUF) by using electrochemical methods, with pure Cu as a control. We studied the in vitro long-term corrosion behaviors in SUF, cytotoxicity to uterine cells (human endometrial epithelial cells and human endometrial stromal cells), in vivo biocompatibility and contraceptive efficacy of pure Cu, H62, and Cu-38 Zn. In the first month, the burst release rate of Cu²⁺ in the Cu-38 Zn group was significantly lower than those in the pure Cu and H62 groups. The in vitro cytocompatibility Cu-38 Zn was better than that of pure Cu and H62. Moreover, Cu-38 Zn showed improved tissue biocompatibility in vivo experiments. Therefore, the contraceptive efficacy of the Cu-38 Zn is still maintained as high as the pure Cu while the adverse effects are significantly eased, suggesting that Cu-38 Zn can be a suitable potential candidate material for IUDs. STATEMENT OF SIGNIFICANCE: The existing adverse effects associated with the intrinsic properties of copper materials for copper-containing intrauterine devices (Cu-IUD) are of concern in their employment. Such as, burst release of cupric ions (Cu²⁺) at the initial stage and an increasingly rough surface of the Cu-IUD. In this work, Cu alloyed with a high amount of bioactive Zn was used for a Cu-IUD. The Cu-38 Zn alloy exhibited reduced burst release of Cu²⁺ within the first month compared with the pure Cu and H62. Furthermore, the Cu-38 Zn alloy displayed significantly improved biocompatibility and a much smoother surface. Therefore, high antifertility efficacy of the Cu-38 Zn alloy was well maintained, while the adverse effects are significantly eased, suggesting that the Cu-38 Zn alloy is promising for a Cu-IUD.

The effect of copper intrauterine device use duration on uterine and ovarian blood flow parameters: A prospective cross-sectional study

PURPOSE

This prospective cross-sectional study aimed to compare uterine and ovarian arterial Doppler signals in regularly menstruating patients who had been using copper intrauterine devices (IUD) for different durations.

METHODS

Four groups of participants were formed (n = 30 for each) depending on the duration of copper IUD use: less than 1 year (group 1), 1 to 3 years (group 2), and over 3 years (group 3). Women without IUDs formed the control group. All participants were called in on the fifth-eighth days of their menstrual cycle for Doppler blood flow assessment. The pulsatility index (PI) and resistance index (RI) values were recorded in uterine and ovarian arteries.

RESULTS

The groups 2 and 3 had significantly higher uterine artery PI and RI values than groups 1 and 4. Furthermore, group 2 had uterine and ovarian artery PI and RI values similar to those of group 3. There was a positive relationship between uterine and ovarian arteries' PI and RI values with the duration of IUD use.

CONCLUSIONS

The presence of an IUD for over a year seems to cause changes in the uterine artery PI and RI values assessed by Doppler ultrasonography.

Biomaterials and Contraception: Promises and Pitfalls

The present state of reproductive and sexual health around the world reveals disparities in contraceptive use and effectiveness. Unintended pregnancy and sexually transmitted infection transmission rates remain high even with current prevention methods. The 20th century saw a contraceptive revolution with biomedical innovation driving the success of new contraceptive technologies with central design concepts and materials. Current modalities can be broadly categorized according to their mode of function: reversible methods such as physical/chemical barriers or hormonal delivery devices via systemic (transdermal and subcutaneous) or localized (intrauterine and intravaginal) administration, and nonreversible sterilization procedures such as tubal ligation and vasectomy. Contraceptive biomaterials are at present dominated by well-characterized elastomers such as polydimethylsiloxane and ethylene vinyl acetate due to their favorable material properties and versatility. Contraceptives alter the normal function of cellular components in the reproductive systems to impair fertility. The purpose of this review is to highlight the bioengineering design of existing methods, explore novel adaptations, and address notable shortcomings in current contraceptive technologies.

Alterations in the endometrium of rats, rabbits, and Macaca mulatta that received an implantation of copper/low-density polyethylene nanocomposite

A copper/low-density polyethylene nanocomposite (nano-Cu/LDPE), a potential intrauterine device component material, has been developed from our research. A logical extension of our previous work, this study was conducted to investigate the expression of plasminogen activator inhibitor 1 (PAI-1), substance P (SP), and substance P receptor (SP-R) in the endometrium of Sprague Dawley rats, New Zealand White rabbits, and Macaca mulatta implanted with nano-Cu/LDPE composite. The influence of the nano-Cu/LDPE composite on the morphology of the endometrium was also investigated. Animals were randomly divided into five groups: the sham-operated control group (SO group), bulk copper group (Cu group), LDPE group, and nano-Cu/LDPE groups I and II. An expression of PAI-1, SP, and SP-R in the endometrial tissues was examined by immunohistochemistry at day 30, 60, 90, and 180 postimplantation. The significant difference for PAI-1, SP, and SP-R between the nano-Cu/LDPE groups and the SO group (P<0.05) was identified when the observation period was terminated, and the changes of nano-Cu/LDPE on these parameters were less remarkable than those of the Cu group (P<0.05). The damage to the endometrial morphology caused by the nano-Cu/LDPE composite was much less than that caused by bulk copper. The nano-Cu/LDPE composite might be a potential substitute for conventional materials for intrauterine devices in the future because of its decreased adverse effects on the endometrial microenvironment.

Biological evaluation of the copper/low-density polyethylene nanocomposite intrauterine device

Devices and materials intended for clinical applications as medical and implant devices should be evaluated to determine their biocompatibility in physiological systems. This article presents results from cytotoxicity assay of L929 mouse fibroblasts culture, tests for skin irritation, intracutaneous reactivity and sensitization, and material implantation tests for the novel copper/low-density polyethylene nanocomposite intrauterine device (nano-Cu/LDPE IUD) with potential for future clinical utilization. Cytotoxicity test in vitro was conducted to evaluate the change in morphology, growth and proliferation of cultured L929 mouse fibroblasts, which in vivo examination for skin irritation (n = 6) and intracutaneous reactivity (n = 6) were carried out to explore the irritant behavior in New Zealand White rabbits. Skin sensitization was implemented to evaluate the potential skin sensitizing in Hartley guinea pigs (n = 35). The materials were implanted into the spinal muscle of rabbits (n = 9). The cytotoxicity grade of the nano-Cu/LDPE IUD was 0-1, suggested that the composite was nontoxic or mildly cytotoxic; no irritation reaction and skin sensitization were identified in any animals of specific extracts prepared from the material under test; similarly to the control sides, the inflammatory reaction was observed in the rabbits living tissue of the implanted material in intramuscular implantation assay. They indicated that the novel composite intrauterine device presented potential for this type of application because they meet the requirements of the standard practices recommended for evaluating the biological reactivity. The nano-Cu/LDPE IUD has good biocompatibility, which is biologically safe for the clinical research as a novel contraceptive device.

An approach to give prospective life-span of the copper/low-density-polyethylene nanocomposite intrauterine device

As a novel copper-containing intrauterine device (IUD), the prospective life-span of the copper/low-density-polyethylene (Cu/LDPE) nanocomposite IUD is very important for the future clinical use and should be given in advance. Here a novel approach, cupric ions accelerated release in diluted nitric acid solution and cupric ions concentration release in various volume of simulated uterine solution (SUS), is reported to verify the type of cupric ions release model of the cylindrical matrix-type nanocomposite IUD, and to obtain the minimal cupric ions release rate that need to ensure contraceptive efficacy and the thickness of copper particles exhausted layer of the cylindrical matrix-type nanocomposite IUD within two difficult immersion durations in experimental volume of SUS, respectively. Using these results, the prospective life-span of the cylindrical matrix-type nanocomposite IUD can be obtained. For instance, the prospective life-span of the novel γ-shape nanocomposite IUD with 25 wt% of copper nanoparticles and 2 mm of diameter and a total weight of 285 mg can be given in advance and it is about 5 years in the future clinical use.

Long-acting contraceptives in adolescents

PURPOSE OF REVIEW

To help clinicians guide adolescent patients to sound choices regarding long-acting contraceptives. The safety, side effects and non-contraceptive benefits of injectable, implantable and intrauterine contraception are detailed.

RECENT FINDINGS

The use of depot medroxyprogesterone acetate contraceptive injections has been associated with declines in teenage pregnancies in the United States. Although the US Food and Drug Administration has placed a black box warning concerning skeletal health and depot medroxyprogesterone acetate, data in adolescents confirm that declines in bone mineral density with depot medroxyprogesterone acetate are fully reversible. Concerns regarding skeletal health should not restrict the initiation or continuation of depot medroxyprogesterone acetate in adolescents. A highly effective, convenient, and easy to insert/remove single rod progestin-only contraceptive implant (Implanon) is now available in the United States. Although not widely used in adolescents, intrauterine devices offer selected adolescents convenient, highly effective, safe birth control. Use of the progestin-releasing intrauterine device (Mirena) is also associated with important non-contraceptive benefits.

SUMMARY

The efficacy and convenience associated with long-acting contraceptives make them indispensable for adolescent patients. This review will help clinicians guide teenage patients towards sound contraceptive choices and the successful long-term use of injectable, implantable and intrauterine methods of birth control.

Effect of implanted Cu/low-density polyethylene nanocomposite on the morphology of endometrium in the mouse

OBJECTIVE

To investigate the damage of endometrium caused by the implanted Cu/low-density polyethylene (LDPE) nanocomposite and the contraceptive effect of this novel copper-containing intrauterine device material.

DESIGN

Experimental animal study.

SETTING

TongJi Medical College of Huazhong University of Science and Technology.

PATIENT(S)

Sixty healthy female mice.

INTERVENTION(S)

Twenty mice received no implants, 20 mice received the Cu/LDPE nanocomposite, and 20 mice received bulk copper.

MAIN OUTCOME MEASURE(S)

Morphologic features of the endometrium, contraceptive effect, and surface condition of the implanted implants.

RESULT(S)

The contraceptive effect of both the Cu/LDPE nanocomposite and bulk copper is 100%, the damage of the endometrium caused by the Cu/LDPE nanocomposite is much less than that caused by bulk copper, and the surface of the implanted Cu/LDPE nanocomposite is much smoother and much softer than that of the implanted bulk copper.

CONCLUSION(S)

The contraceptive effect of the Cu/LDPE nanocomposite is comparable with that of bulk copper, and the damage of the endometrium caused by the Cu/LDPE nanocomposite is much less than that caused by bulk copper. The endometrium injury is related to the surface condition of the implanted intrauterine device material.

Intrauterine contraception: the pendulum swings back

Intrauterine contraception is the most widely used method of reversible fertility regulation in the world. Finally, IUC is undergoing a renaissance in the US and it's role will expand as new devices and systems are developed and as old biases among clinicians and women are erased. Successful fertility regulation is a defining factor of the overall health of a population; the expanded use of IUC can help achieve that public health success.