Reversible female contraceptives: historical, current, and future perspectives†

Contraception is a practice with extensive and complicated social and scientific histories. From cycle tracking, to the very first prescription contraceptive pill, to now having over-the-counter contraceptives on demand, family planning is an aspect of healthcare that has undergone and will continue to undergo several transformations through time. This review provides a comprehensive overview of current reversible hormonal and non-hormonal birth control methods as well as their mechanism of action, safety, and effectiveness specifically for individuals who can become pregnant. Additionally, we discuss the latest Food and Drug Administration (FDA)-approved hormonal method containing estetrol and drospirenone that has not yet been used worldwide as well as the first FDA-approved hormonal over-the-counter progestin-only pills. We also review available data on novel hormonal delivery through microchip, microneedle, and the latest FDA-approved non-hormonal methods such as vaginal pH regulators. Finally, this review will assist in advancing female contraceptive method development by underlining constructive directions for future pursuits. Information was gathered from the NCBI and Google Scholars databases using English and included publications from 1900 to present. Search terms included contraceptive names as well as efficacy, safety, and mechanism of action. In summary, we suggest that investigators consider the side effects and acceptability together with the efficacy of contraceptive candidate towards their development.

Serine protease inhibitor disrupts sperm motility leading to reduced fertility in female mice†

Inhibition of the sperm transport process in the female reproductive tract could lead to infertility. We previously showed that a pan-serine protease inhibitor, 4-(2-aminoethyl)benzenesulfonyl fluoride (AEBSF), blocked semen liquefaction in vivo and resulted in a drastic decrease in the number of sperm in the oviduct of female mice. In this study, we used a mouse model to test the efficacy of AEBSF as a reversible contraceptive, a sperm motility inhibitor, and a spermicide. Additionally, this study evaluated the toxicity of AEBSF on mouse vaginal tissues in vivo and human endocervical cells in vitro. We found that female mice treated with AEBSF had significantly less pups born per litter as well as fertilization rates in vivo compared to the vehicle control. We then showed that AEBSF reduced sperm motility and fertilization capability in vitro in a dose-dependent manner. Furthermore, AEBSF also exhibited spermicidal effects. Lastly, AEBSF treatment in female mice for 10 min or 3 consecutive days did not alter vaginal cell viability in vivo, similar to that of the vehicle and non-treated controls. However, AEBSF decreased cell viability of human ectocervical (ECT) cell line in vitro, suggesting that cells in the lower reproductive tract in mice and humans responded differently to AEBSF. In summary, our study showed that AEBSF can be used as a prototype compound for the further development of novel non-hormonal contraceptives for women by targeting sperm transport in the female reproductive tract.

Roles of steroid hormones in oviductal function

The oviduct (known as the fallopian tube in humans) is the site for fertilization and pre-implantation embryo development. Female steroid hormones, estrogen and progesterone, are known to modulate the morphology and function of cells in the oviduct. In this review, we focus on the actions of estrogen and progesterone on secretory, ciliated, and muscle cell functions and morphologies during fertilization, pre-implantation embryo development, and embryo transport in humans, laboratory rodents and farm animals. We review some aspects of oviductal anatomy and histology and discuss current assisted reproductive technologies (ARTs) that bypass the oviduct and their effects on embryo quality. Lastly, we review the causes of alterations in secretory, ciliated, and muscle cell functions that could result in embryo transport defects.

IL-6-like cytokines and cancer cachexia: consequences of chronic inflammation

An estimated 30% of cancer deaths are attributed to cachexia and its consequences. Cachexia (wasting syndrome) is the hypercatabolism of the body's carbon sources, proteins and lipids, for conversion into energy. It is induced by a variety of pathological conditions, including cancer. Among the inflammatory responses to cancer is the synthesis of cytokines, including IL-6 and related cytokines. These cytokines have been found to induce cachexia by altering metabolism of lipids and proteins. IL-6-like cytokines have been found to inhibit lipid biosynthesis by adipocytes, which increased the rate of lipid catabolism. Others have described the atrophy and increased catabolism of muscle protein due to IL-6. A cytokine closely-related to IL-6 is leptin, which plays a major role in lipid metabolism under normal conditions. The role of leptin in pathological conditions such as cancer cachexia has not yet been fully elucidated. Detailed mechanistic information about the induction of cancer cachexia by IL-6-like cytokines requires more research.

Cancer cachexia is mediated in part by the induction of IL-6-like cytokines from the spleen

The development of cancer cachexia has been linked to cytokines related to interleukin6 (IL-6). We examined the kinetics of IL-6, IL-11, oncostatinM (OSM) and leukaemia inhibitory factor (LIF) induction in the splenocytes of tumour-bearing mice. Using a lung carcinoma line, which grows in C57BL/6J mice, we observed that when the tumour grew and cachexia was observed, the splenocytes produced IL-6, IL-11, and OSM, but not LIF. Cytokine expression was observed within 1 week (day 3 for IL-6 and IL-11, and day 1 for OSM) of administration of tumour cells, and was observed in splenocytes without tumour metastases to the spleen. Cytokine expression preceded cachexia (determined by changes in serum triglyceride levels and decrease in epididymal fat-pad weights) development by over 1 week. Exogenous administration of IL-11 resulted in the accelerated onset of cachexia, compared to control protein treatment, but without an effect on the tumour burden. In vivo treatment with a neutralizing dose of anti-OSM antibody inhibited the triglyceride dysregulation only until the synthesis of IL-6 and IL-11 began in the spleen (day 3). Afterward, IL-6 and IL-11 induced lipid catabolism in the absence of functional OSM. We conclude from the data described above that cachexia developed due to a systemic cytokine response induced by a tumour burden, and that IL-6-like cytokines contributed independently to lipid hypercatabolism in the aetiology of cancer cachexia.

Constitutive expression of IL-6-LIKE cytokines in normal bone marrow: implications for pathophysiology of myeloma

Myeloma is a neoplasm thought to "home" to bone marrow. However, evidence for bone-marrow-specific receptors or adhesion molecules expressed on myeloma cells is scanty. Initial myeloma expansion is thought to be due to IL-6 and/or related cytokines. Previous determinations of cytokine expression in bone marrow were performed on bone marrow stromal lines; these findings may not reflect the constitutive pattern of expression in situ. Intracytoplasmic staining for IL-6-like cytokines revealed constitutive expression of some factors in the bone marrow of normal mice, but not spleens. Spleens of myeloma-transplanted SCID mice expressed IL-6-like cytokines, indicative of induction of expression by myeloma. Some cytokines expressed in bone marrow induced myeloma proliferation in the presence of dexamethasone, demonstrating dependence of the myeloma on these cytokines. Our data imply that, rather than "homing" to bone marrow, myeloma cells proliferated within marrow cavities more than in other organs because of growth factors constitutively expressed by bone marrow cells. As myeloma progressed, we observed the induction of growth factor expression in spleen cells. Furthermore, because cytokines other than IL-6 may induce myeloma cell proliferation, therapy aimed at neutralizing IL-6 may not be the most effective method to treat this disease. These findings have implications for both the pathophysiology and therapy of multiple myeloma.

A model that reproduces syndromes associated with human multiple myeloma in nonirradiated SCID mice

A human myeloma line was used to create a model of human multiple myeloma in vivo that would reproduce the pathophysiology of the disease, including the cachexia associated with cancer. Unirradiated severe combined immunodeficient (SCID) mice were used as surrogate hosts for in vivo experiments that allowed the effects of autocrine (human) verus paracrine (murine) cytokines on the development of myeloma to be studied. Serum levels of human paraprotein increased over time and with the number of cells transplanted. Transplanted mice developed major syndromes, cachexia and paralysis (due to invasion of bones by myeloma cells), associated with multiple myeloma. Analyses of serum samples obtained from transplanted mice revealed that when the mice were terminal, total serum protein decreased on average by 20%, whereas serum triglycerides decreased on average by 50%. These data indicate the mice were cachectic, which was confirmed by necropsy. The mice had low but measurable levels of both human and murine interleukin (IL)-6, soluble IL-6 receptor, and murine IL-10 in their sera. The presence of these cytokines and the IL-6 receptor in sera are also characteristics of human myeloma in patients. Since human cells do not respond to murine IL-6, it was possible to demonstrate clearly the importance of autocrine IL-6 in establishing myeloma in situ. By reproducing both the hallmarks of a cancer as well as the accompanying paraneoplastic syndromes, this model should be useful in designing more effective therapies for both the primary cancer as well as the accompanying secondary diseases.

IL-6: insights into novel biological activities

IL-6 has many novel activities both within the adaptive immune system and without. It has therapeutic potential in acute inflammation, such as toxic or septic shock, and it is a potential target for cachexia, multiple myeloma, and osteoporosis. Further work on these aspects of IL-6 biology should yield new insight into the possibility of IL-6 both as a therapeutic agent and as a target for antagonists.

Interleukins 6 and 11 protect mice from mortality in a staphylococcal enterotoxin-induced toxic shock model

BALB/By mice given doses of D-galactosamine plus Staphylococcus aureus enterotoxin B die within 48 h of administration. The cause of death is a syndrome much like toxic shock syndrome in humans. We used this model to investigate the role of two cytokines, interleukin 6 and interleukin 11, which share the signal transducing subunit, gp130, of their respective receptors. We observed that pretreatment of mice with antibody to interleukin 6 increased mortality from 55% to nearly 90% (P < 0.001), while pretreatment with either cytokine reduced death. The protection was dose dependent; however, interleukin 6 was about 10-fold more potent that interleukin 11. These data indicate that endogenous interleukin 6 plays a protective role in attenuating acute inflammatory responses; furthermore, interleukin 6 and interleukin 11 can abrogate T-cell activation due to triggering by superantigen. A possible clinical role for these cytokines in the treatment of toxic shock merits further investigation.

Macrophage colony stimulatory factor-activated bone marrow macrophages suppress lymphocytic responses through phagocytosis: a tentative in vitro model of Rosai-Dorfman disease

NBXFO hybridoma cells produced macrophage colony-stimulating factor (M-CSF), which stimulated the growth of murine bone marrow-derived macrophages with potent suppressor activity. These macrophages suppressed lymphocyte responses to mitogens and antigens in a dose-dependent manner. Using a transwell chamber, we demonstrated that macrophages needed physical contact with the lymphocytes to suppress lymphocyte proliferation on day 1 in the concanavalin A mitogen reaction. In addition, no soluble suppressor factor was detected at that time. The number of lymphocytes disappeared with time when they were cocultured with the macrophages. Electron microscopy revealed that the macrophage phagocytosized the lymphocytes after 7 1/2 h. Dextran sulfate, heparan, and fucoidan prevented the macrophages from suppressing the lymphocytes. This phenomenon resembles the human disease sinus histiocytosis, also called Rosai-Dorfman disease, in which macrophages (histiocytes) phagocytosize autologous lymphocytes; occasionally, this disease is associated with immunological abnormalities. Thus we believed that macrophage-activating cytokines, such as M-CSF, may stimulate macrophages to phagocytose lymphocytes in vivo.

The identification of the neonatal NBXFO hybridoma cell and its mediator

The neonatal spleen:myeloma hybridoma cell, NBXFO, with immunosuppressive properties supported rodent hematopoietic colony formation. We identified this hybridoma to be an undifferentiated fibroblast that produced macrophage colony-stimulating factor (M-CSF). The bone marrow cells that grew in the presence of the NBXFO supernate were macrophages and were immunosuppressive towards lymphocytes. Neutralizing anti-M-CSF antibody partially inhibited the actions of the neonatal splenic suppressor cells. Neonatal splenocytes, but not the other parental cell line, FO, induced macrophage colony formation, possessed surface-associated M-CSF, and possessed M-CSF-specific transcripts. Therefore, we believe that the M-CSF-producing phenotype was contributed by a fibroblastic stromal cell and that these stromal cells could be responsible for the in situ generation of neonatal splenic suppressor cells.

Oncostatin M stimulates proliferation in B9 hybridoma cells: potential role of oncostatin M in plasmacytoma development

Oncostatin M was found to stimulate the IL-6-addicted hybridoma line B9. Leukaemia inhibitory factor did not stimulate proliferation of this line. Both of these factors bind to the gp130 of the IL-6 receptor. In another cell line that is stimulated by LIF (DA.1), neither IL-6 nor oncostatin M stimulated proliferation. Previously it had been thought that the gp130 alone is sufficient to bind ligand and transduce signal and that oncostatin M could bind to and activate the LIF receptor, but these data show this is not always the case. Mice primed with Pristane were found to have IL-6 in their sera and peritoneal fluid only at a few time points following Pristane treatment; this was determined by IL-6-specific ELISA. When the same samples were analysed on IL-6-addicted B9 cells, stimulatory activity was found at all time points. When the Pristane-primed samples were assayed for oncostatin M activity in the A375 melanoma assay, there was oncostatin M activity at various time points. IL-6 did not have activity on the A375 cells. These data indicate that oncostatin M play a role in the generation of plasmacytoma in vivo.

Protective role of interleukin 6 in the lipopolysaccharide-galactosamine septic shock model

C57BL/6J mice given low doses of lipopolysaccharide (LPS) (100 ng per mouse) plus D-galactosamine (8 mg per mouse) die within 24 h following LPS administration. We used this septic shock model to confirm the role of tumor necrosis factor in mortality using a monoclonal antibody to tumor necrosis factor to prevent lethality. Furthermore, we demonstrated that interleukin 6, rather than playing a lethal role, protected mice against death in this septic shock model. Antibody to interleukin 6 did not affect the fatal outcome in this low-LPS-dose model. However, pretreatment with antibody to tumor necrosis factor did protect the mice against death, in a dose-dependent manner. Moreover, mortality was enhanced by pretreatment with antibody to interleukin 6 when tumor necrosis factor was partly limited by anti-tumor necrosis factor treatment. Mortality was significantly reduced by pretreatment with both recombinant interleukin 6 and low doses of antibody to tumor necrosis factor; in the absence of the low dose of antibody to tumor necrosis factor, interleukin 6 alone did not confer any protection. These data demonstrate in vivo antagonistic activities of tumor necrosis factor and interleukin 6 and show that interleukin 6 can play a protective role against death from septic shock.

Two pathways of signal transduction are activated in the same cell by different cytokines

NFS60, a murine leukemia cell line, responds to both interleukin 3 and 6 by proliferating, apparently by different signal transduction pathways. Although stimulation by both cytokines increases the uptake of 3H-arachidonic acid, the response to IL-6 was much faster. Furthermore, the effect of various arachidonic acid metabolites on the response to cytokine was different. PGE2 inhibited IL-6-induced proliferation and potentiated the response to IL-3. Additionally the G proteins which coupled the IL-3 and IL-6 receptor to the proliferative response are probably different, based on the ability of cholera toxin to inhibit the IL-3 but not the IL-6 response. These data are evidence of two pathways of signal transduction.

Cytokine inhibition by a novel steroid, mometasone furoate

Mometasone furoate (9 alpha, 21 dichloro-11 beta, 17 alpha dihydroxy-16 alpha methyl-1,4 pregnadiene-3, 20 dione-17-[2'] furoate) was an unexpectedly potent inhibitor of the in vitro production of three inflammatory cytokines, IL-1(1), IL-6, and TNF-alpha. The potency of mometasone furoate in inhibiting cytokine production was compared to that of hydrocortisone, betamethasone, dexamethasone, and beclomethasone. IL-6 and TNF-alpha were both produced by WEHI-265.1 (murine myelomonocytic leukemia) cells following stimulation by lipopolysaccharide (LPS). Twenty-four hours after stimulation by LPS, the cell-free supernatant fluids were removed. Their cytokine content was analyzed using ELISAs specific for each cytokine. IL-1 synthesis was induced in the harvested peritoneal macrophages of BALB/c mice by incubation with LPS for twenty-four hours. The IL-1 content in the cell-free supernatant fluids was determined by the thymocyte-costimulator bioassay. Using these systems, mometasone furoate was found to be the most potent steroid tested for inhibiting the production of the three cytokines. The IC50's were 0.05 nM (IL-1), 0.15 nM (IL-6), and 0.25 nM (TNF-alpha). The inhibition of the production of proinflammatory mediators by extremely low concentrations of mometasone furoate suggests that this steroid should be highly effective in various disorders.

IL 3 and IL 6 do not induce bone resorption in vitro

Bone resorption in vitro and in vivo can be induced by interleukin 1 (IL 1) and tumor necrosis factor (TNF), both of which are potent inflammatory cytokines. Additionally, there are other factors produced by cells which can active osteoclasts. Because diverse factors are involved in bone resorption, we examined the role of two other inflammatory cytokines, IL 3 and IL 6. IL 3 has been shown to induce the formation of osteoclast-like cells from precursors, while IL 6 is a potent mediator of inflammatory responses. Osteoclast activity in neonatal mouse calvaria was measured as 45Ca released into the supernatant fluid following a 48 hr incubation period with cytokine. Our results show that while parathyroid hormone (PTH) and IL 1 are potent inducers of bone resorption, neither IL 3 nor IL 6 displayed such activity.

The effect of dual inhibitor, SK&F 86002, on helper T cell functions

SK&F 86002, a mixed cyclooxygenase-lipoxygenase inhibitor, was examined for its effects on helper T cell functions. The drug was found to inhibit concanavalin A-induced mitogenesis of splenic T cells (IC50 = 13 microns), the mixed lymphocyte response (IC50 = 16 microM), and proliferation of antigen specific T cells (cloned line, IC50 = 11 microM; uncloned line, IC50 = 13 microM). In contrast, another mixed cycloxygenase-lipoxygenase inhibitor, BW775c, did not have such effects at non-cytotoxic levels. These T cell functions are believed to be dependent on the effects of elaborated IL-1. SK&F 86002 has been shown to inhibit the production of mature IL-1 (IC50 = 1 microM), possibly accounting for the anti-inflammatory effects of the drug in rheumatoid arthritis models. In an in vivo model of contact sensitivity, SK&F 86002 was able to inhibit mouse footpad swelling, demonstrating additional anti-inflammatory activity. As an inhibitor of IL-1 synthesis or release, SK&F 86002 may be useful for the treatment of T cell-dependent inflammation.

IL-3 induces differentiation of bone marrow precursor cells to osteoclast-like cells

IL-3, a cytokine with hematopoietic differentiating capability, induced murine bone marrow cells to differentiate into cells resembling osteoclasts. The cells resulting from treatment with IL-3 were multi-nucleated and demonstrated tartrate-resistant acid-phosphatase activity, as do resident osteoclasts found in bone. IL-3-induced osteoclast-like cell development in the absence of serum-derived vitamin D metabolites, and a mAb that inhibited IL-3-induced proliferation of an addicted cell line also inhibited the development of osteoclasts in the presence of IL-3. The same Ab had no effect on 1 alpha, 25-dihydroxyvitamin D3-induced differentiation of osteoclasts. This newly described function of IL-3 may indicate a role for activated T cells in the bone resorption seen with rheumatoid arthritis.

IL-3 induces differentiation of bone marrow precursor cells to osteoclast-like cells

IL-3, a cytokine with hematopoietic differentiating capability, induced murine bone marrow cells to differentiate into cells resembling osteoclasts. The cells resulting from treatment with IL-3 were multi-nucleated and demonstrated tartrate-resistant acid-phosphatase activity, as do resident osteoclasts found in bone. IL-3-induced osteoclast-like cell development in the absence of serum-derived vitamin D metabolites, and a mAb that inhibited IL-3-induced proliferation of an addicted cell line also inhibited the development of osteoclasts in the presence of IL-3. The same Ab had no effect on 1 alpha, 25-dihydroxyvitamin D3-induced differentiation of osteoclasts. This newly described function of IL-3 may indicate a role for activated T cells in the bone resorption seen with rheumatoid arthritis.

Macrophage modulation of retinal pigment epithelial cell migration and proliferation

Macrophages are fully differentiated cells that do not synthesize an extracellular matrix and do not contract; they do, however, produce substances that modify the behavior and functions of other cells, particularly those involved in the inflammatory and immune responses. Since macrophages are a ubiquitous component of periretinal membranes, we sought to determine whether they modulate proliferation and/or migration of retinal pigment epithelial (RPE) cells, functions that may be essential for the development of proliferative vitreoretinopathy (PVR). Using an in vitro assay, we found that macrophage supernatant contains factors that stimulate proliferation and migration of cultured human RPE cells. Since interleukin-1 (IL-1) is a product of activated macrophages that modulates a number of cellular functions, we also examined its effect on RPE proliferation and migration. We found that IL-1 increased migration but did not affect proliferation, and thus could not duplicate the effect of macrophage supernatant. Injection of activated macrophages into the vitreous of rabbits which had a retinal hole stimulated RPE cell proliferation in the area of the retinal hole, where the RPE cells were exposed. These findings suggest the ability of macrophages to modulate functions of RPE cells that are thought to be critical for the development of PVR. Macrophages may thus be an important part of the vitreous environment that favors the development of PVR.

Relative allergenic potential of four proteases used as contact lens cleaners

The general use of enzymatic cleaners for soft contact lenses has led to reports of incidents of allergic reactions in previously sensitized patients. In light of this, experiments were performed to assess the relative allergenic potential of four such enzymes: papain, subtilisin A, subtilisin B, and pancreatin. Mice immunized intraperitoneally (i.p.) with either subtilisin A or papain exhibited little serum immunoglobulin E (IgE), even after tertiary doses of protein. Primates immunized intradermally (i.d.) with the four enzymes showed various levels of response to challenges: none to papain, mild to moderate to subtilisin A and pancreatin, and severe to subtilisin B. Finally, guinea pigs instilled ocularly with enzymes weekly for 15 weeks exhibited significant hyperemia and chemosis only to the positive control protein, ovalbumin, and not to any of the enzymes tested. We conclude that three of the four enzymes tested have low potential to sensitize human beings, and, further, that animal models may find increased use in screening products of biotechnology.

The role of arachidonic acid metabolism in IL-3-induced proliferation

The role of arachidonic acid metabolites as second messengers in the IL-3-induced activation of DA-1 cells was examined. By using inhibitors of either the cyclooxygenase (CO) or lipoxygenase (LPO) pathways, we determined that neither prostaglandins nor leukotrienes were involved in signal transduction, since aspirin, indomethacin, meclofenamic acid, and nordihydroguaiaretic acid (NDGA) failed to inhibit the proliferation response of DA-1 cells to IL-3. Furthermore, two combination CO/LPO inhibitors, benoxaprofen and BW755c, failed to inhibit DA-1 proliferation. A new CO/LPO compound examined, SK&F 86002, did inhibit proliferation (IC50 = 30 microM +/- 14, N = 11), leading us to conclude this drug has other actions besides CO/LPO inhibition. Finally, direct measurement of 3H-arachidonic acid uptake by DA-1 cells failed to show a difference in the amount of 3H-arachidonic acid incorporated in the presence of limiting or saturating amounts of IL-3. We conclude from these data that arachidonic acid metabolites are not involved in transmembrane signalling by IL-3 in DA-1 cells.

The immune response to a schistosomacide, amoscanate. I. Serum antibody responses

A potent antischistosomal drug, Amoscanate, was found to be immunogenic to mice and Cebus apella monkeys. The drug was readily haptenated to proteins under relatively mild conditions. The Amoscanate-protein conjugates were observed to be immunogenic when injected into the footpads of several strains of mice. However, such protein conjugates were not found to raise IgE antibody to the drug in high-responder strains using several procedures. When the formulated drug (dissolved in oil) was fed to CD 1 mice, a rise in serum antibody against the drug was noted 1 week following the primary dose. This is preliminary evidence that the drug, or a cross-reactive metabolite, becomes covalently bound to proteins in vivo. Cebus apella monkeys fed the drug exhibited a rise in anti-Amoscanate antibody one month after a second oral dose. These data suggest that the immunogenicity of Amoscanate is readily detected; furthermore, since there is no lasting immunity to schistosomiasis, thus necessitating multiple administration of the drug, the possibility that serum antibody titers to Amoscanate may interfere with its therapeutic efficacy cannot be overlooked.

The immune response to a schistosomacide, amoscanate. II. Cell-mediated immune responses

A potent antischistosomal drug, Amoscanate, was found to induce vigorous serum antibody responses when either fed or administered parenterally as a drug-protein conjugate. Because of preliminary evidence that the drug could bind covalently to proteins in vivo, we decided to investigate the possibility that the drug could act as a contact sensitizing agent like DNCB. It was found that Amoscanate could induce a delayed-type hypersensitivity (DTH) response when painted on the shaved skin of guinea pigs. Moreover, the type of DTH response elicited was found to be cutaneous basophilic hypersensitivity (CBH). The significance of these findings are discussed.