Increased PGE2 from human monocytes isolated in the luteal phase of the menstrual cycle. Implications for immunity?

ACTH impairs the migratory and secretory profile of mononuclear cells during proestrus in cattle

The aim was to evaluate the effect of ACTH on the mechanisms involved in peripheral blood mononuclear cells (PBMCs) infiltration into the ovary during dairy cattle proestrus. Regarding this, proper expression pattern of adhesion molecules must take place both in PBMCs and in endothelial cells. Argentinian Holstein cows (n = 12) were treated with 100 IU of ACTH every 12 h for 4 days before ovulation when ovariectomy was performed (day 18). Blood samples were taken on day 15 (0 h) and immediately before (72 h) and after (74 h) the last ACTH administration. In PBMCs, flow cytometry was performed to analyze CD44, CD11b and CD62-L expression along with gene expression of chemokines' receptors. Interleukin (IL)-4 and tumor necrosis factor-α (TNF-α) production was analyzed by flow cytometry after exposing PBMCs to autologous follicular fluid. In ovarian blood vessels, expression of the vascular endothelium cell adhesion-1 (VCAM-1) and the platelet endothelial cell adhesion molecule-1 was evaluated by immunohistochemistry. In T-lymphocytes, the expression of CD44 and CD11b was lower at 72 h in ACTH-treated cows (P < 0.05). In monocytes, the expression of CD11b and CD62-L was lower at 72 h in ACTH-treated cows (P < 0.05). Also, the percentage of IL-4+ cells was higher in ACTH-treated cows, meanwhile, the percentage TNF-α+ cells was lower in ACTH-treated cows (P < 0.05). Finally, in the vessels associated with the preovulatory follicle VCAM-1 immunoexpression was lower in ACTH-treated cows (P < 0.05). Here, we present novel insights into the effect of stress during the preovulatory period on the inflammatory pathway necessary for ovulation.

The effects of menstrual cycle phases on immune function and inflammation at rest and after acute exercise: A systematic review and meta-analysis

The immune system plays an important role in mediating exercise responses and adaptations. However, whether fluctuating hormone concentrations across the menstrual cycle may impact these processes remains unknown. The aim of this systematic review with meta-analysis was to compare baseline concentrations as well as exercise-induced changes in immune and inflammatory parameters between menstrual cycle phases. A systematic literature search was conducted according to the PRISMA guidelines using Pubmed/MEDLINE, ISI Web of Science, and SPORTDiscus. Of the 159 studies included in the qualitative synthesis, 110 studies were used for meta-analysis. Due to the designs of the included studies, only the follicular and luteal phase could be compared. The estimated standardized mean differences based on the random-effects model revealed higher numbers of leukocytes (-0.48 [-0.73; -0.23], p < 0.001), monocytes (-0.73 [-1.37; -0.10], p = 0.023), granulocytes (-0.85 [-0.1.48; -0.21], p = 0.009), neutrophils (-0.32 [-0.52; -0.12], p = 0.001), and leptin concentrations (-0.37 [-0.5; -0.23], p = 0.003) in the luteal compared to the follicular phase at rest. Other parameters (adaptive immune cells, cytokines, chemokines, and cell adhesion molecules) showed no systematic baseline differences. Seventeen studies investigated the exercise-induced response of these parameters, providing some indications for a higher pro-inflammatory response in the luteal phase. In conclusion, parameters of innate immunity showed cycle-dependent regulation at rest, while little is known on the exercise responses. Due to a large heterogeneity and a lack of cycle phase standardization among the included studies, future research should focus on comparing at least three distinct hormonal profiles to derive more specific recommendations for exercise prescription.

Differential susceptibility according to gender in the association between air pollution and mortality from respiratory diseases

This study analyzed the association between air pollution and deaths from respiratory diseases, considering differential susceptibility according to gender. The authors used daily deaths from respiratory diseases (ICD-10, J00-J99), PM10, SO2, and O3 levels, and meteorological indicators in Volta Redonda, Rio de Janeiro State, Brazil, from January 2002 to December 2006. The association was estimated by Poisson regression using generalized additive models, where the increase in risk of deaths from PM10 to lag 1 was 10.01% (95%CI: 1.81-18.88%) in the total female population and 10.04% (95%CI: 0.90-20.02%) in elderly women. The increase in risk of deaths from PM10 to lag 9 was 8.25% in the total male population (95%CI: 0.86-16.18%) and 10.80% (95%CI: 2.18-20.15%) in elderly men. For exposure to SO2 and O3, the risk was significant in the total male population and the elderly, respectively. The results emphasize the need for further studies, focusing on modification of the effects of air pollution on health.

Gingival inflammation and interleukin-1 beta and tumor necrosis factor-alpha levels in gingival crevicular fluid during the menstrual cycle

BACKGROUND

Hormonal changes during puberty, pregnancy, and menopause may impact periodontal tissues by altering the host response. There are only a few studies that examined gingival changes during the menstrual cycle. This longitudinal and prospective study aims to investigate clinical and laboratory markers of gingival inflammation in women at different phases during their menstrual cycles.

METHODS

Twenty-seven females were included in this study. Subjects were given oral hygiene instructions before the study, and their plaque index scores were recorded once a week for 2 months. The duration and regularity of the menstrual cycle were also checked at the same time. The gingival index and bleeding on probing (BOP) were recorded. Probing depths were measured to assess the periodontal condition of the subjects. Gingival crevicular fluid (GCF) was collected to analyze the levels of interleukin (IL)-1beta and tumor necrosis factor-alpha on the first menstruation day (MD), estimated ovulation day (OD), and estimated predominant progesterone secretion day (PgD). These exact menstrual cycle days were determined according to serum progesterone and estradiol levels.

RESULTS

BOP and IL-1beta levels in GCF showed significant increases from the MD to PgD under optimal plaque control. Among the 12 subjects that had premenstrual symptoms, six subjects reported oral complaints during the premenstrual period, whereas apthous lesions were more frequent during the menstruation period.

CONCLUSION

These results demonstrate that the fluctuation of sex steroid hormones impact gingival inflammation during menstruation.

Sex hormones and mucosal wound healing

Wound healing studies, which have chiefly examined dermal tissues, have reported a female advantage in healing rates. In contrast, our laboratory recently demonstrated women heal mucosal wounds more slowly than men. We hypothesized sex hormones influence wound healing rates, possibly through their modulating effects on inflammation. This study involved 329 younger subjects aged 18-43 (165 women, 164 men) and 93 older subjects aged 50-88 (60 women, 33 men). A 3.5mm diameter wound was created on the hard oral palate and videographed daily to assess wound closure. Blood collected at the time of wounding was used to assess circulating testosterone, progesterone and estradiol levels, and in vitro cytokine production in response to LPS. No strong associations were observed between healing times and estradiol or progesterone levels. However, in younger subjects, lower testosterone levels related to faster wound closure. Conversely, in older women higher testosterone levels related to (1) lower inflammatory responses; and (2) faster healing times. No such relationships were seen in older men, or in women taking oral contraceptives or hormone replacement therapy [HRT]. Older women (50-54 years) not yet experiencing menopause healed similarly to younger women and dissimilarly from age-matched post-menopausal women. This suggests that the deleterious effects of aging on wound healing occur secondary to the effects of menopause. Supporting this, there was evidence in post-menopausal women that HRT augmented wound closure. Overall, this study suggests that human mucosal healing rates are modulated by testosterone levels. Based upon when between-group differences were observed, testosterone may impact upon the proliferative phase of healing which involves immune processes such as re-epithelialization and angiogenesis.

Human monocytes but not dendritic cells are killed by blocking of autocrine cyclooxygenase activity

Dendritic cells (DCs), in peripheral tissues, derive mostly from blood precursors that differentiate into DCs under the influence of the local microenvironment. Monocytes constitute the main known DC precursors in blood and their infiltration into tissues is up-regulated during inflammation. During this process, the local production of mediators, like prostaglandins (PGs), influence significantly DC differentiation and function. In the present paper we show that treatment of blood adherent mononuclear cells with 10microM indomethacin, a dose achieved in human therapeutic settings, causes monocytes' progressive death but does not affect DCs viability or cell surface phenotype. This resistance of DCs was observed both for cells differentiated in vitro from blood monocytes and for a population with DCs characteristics already present in blood. This phenomenon could affect the local balance of antigen-presenting cells, influence the induction and pattern of immune responses developed under the treatment with non-steroidal anti-inflammatory drugs and, therefore, deserves further investigation.

Influence of the estrous cycle on tolerance development to LPS-induced sickness behaviors in rats

The relations between the estrous cycle, inflammatory responses and the development of tolerance to endotoxin were examined. Female Long-Evans rats were injected intraperitoneally with lipopolysaccharide (LPS; 200 microg/kg) or saline vehicle at 08:00h on either diestrus (D) or proestrus (P). Ninety-five minutes after injection locomotor activity was assessed in an automated non-novel open-field for 20 min. To assess tolerance development to LPS, rats were re-injected at the next identical stage (i.e. 4 days later; groups: DD, PP) or at the alternate stage (i.e. 6 days later; groups: DP, PD) of the estrous cycle and locomotor activity was again assessed. On Test Day 1 all groups injected with LPS exhibited similar significant activity decrements, regardless of the stage of the estrous cycle. However, on Test Day 2 rats which received both injections of LPS during proestrus (PP) showed no signs of tolerance development, whereas rats in all other groups were tolerant to LPS. In a follow up study, the time between injections was extended to 8 days. Still the animals injected both times at proestrus showed no signs of tolerance to LPS after the second injection. Thus, the stages of the estrous cycle both at the time of initial exposure and of re-exposure appear critical in the formation of behavioral tolerance to LPS in rats.

Inhalation of ultrafine particles alters blood leukocyte expression of adhesion molecules in humans

Ultrafine particles (UFPs; aerodynamic diameter < 100 nm) may contribute to the respiratory and cardiovascular morbidity and mortality associated with particulate air pollution. We tested the hypothesis that inhalation of carbon UFPs has vascular effects in healthy and asthmatic subjects, detectable as alterations in blood leukocyte expression of adhesion molecules. Healthy subjects inhaled filtered air and freshly generated elemental carbon particles (count median diameter approximately 25nm, geometric standard deviation approximately 1.6), for 2 hr, in three separate protocols: 10 microg/m3 at rest, 10 and 25 microg/m3 with exercise, and 50 microg/m3 with exercise. In a fourth protocol, subjects with asthma inhaled air and 10 microg/m3 UFPs with exercise. Peripheral venous blood was obtained before and at intervals after exposure, and leukocyte expression of surface markers was quantitated using multiparameter flow cytometry. In healthy subjects, particle exposure with exercise reduced expression of adhesion molecules CD54 and CD18 on monocytes and CD18 and CD49d on granulocytes. There were also concentration-related reductions in blood monocytes, basophils, and eosinophils and increased lymphocyte expression of the activation marker CD25. In subjects with asthma, exposure with exercise to 10 microg/m3 UFPs reduced expression of CD11b on monocytes and eosinophils and CD54 on granulocytes. Particle exposure also reduced the percentage of CD4+ T cells, basophils, and eosinophils. Inhalation of elemental carbon UFPs alters peripheral blood leukocyte distribution and expression of adhesion molecules, in a pattern consistent with increased retention of leukocytes in the pulmonary vascular bed.

The immunosuppressive potential of misoprostol--efficacy and variability

Existing evidence on the immunosuppressive efficacy of prostaglandin E (PGE) and its analogues in vivo is conflicting. We investigated the effect of misoprostol, an orally available PGE1 analogue, on T-cell proliferation, Th cell-derived cytokine production, and phagocytosis in healthy volunteers. All participants (n=20) received increasing doses of misoprostol (0-400 microg). Blood was drawn before and after intake. Misoprostol intake caused a time- and dose-dependent reduction of anti-CD3-stimulated cell proliferation. Whereas the synthesis of Th1 cytokines (IL-2 and IFN-gamma) was dose-dependently reduced, IL-10 expression was increased at lower misoprostol doses. Concerning IL-4 expression, we observed an increased IL-4 production in males, but a decreased IL-4 production in females. Misoprostol intake also reduced phagocytosis activity in a dose-dependent manner. At least in part our results explain the immunosuppressive effects of misoprostol observed in vivo. The considerable interindividual variability as well as gender-specific differences seem to account for the variability of clinical study results.

Prednisolone pharmacokinetics and pharmacodynamics in relation to sex and race

Prednisolone pharmacokinetics (PK) and pharmacodynamics (PD) were investigated in relation to sex and race in white males, black males, white females, and black females (n = 8/group) after a single oral dose (0.27 mg/kg) of prednisone. The study consisted of baseline and prednisone phases with 32-hour sampling in each phase. Women were studied during the luteal phase of their menstrual cycle. Total and free plasma prednisolone concentrations were assayed by HPLC and ultrafiltration, and pharmacokinetic data were analyzed by compartmental fitting using WinNonlin. Plasma cortisol concentrations were assayed by HPLC; T-helper, T-suppressor lymphocyte, and neutrophil cell counts were determined by FACS and hemocytometry, and these pharmacodynamic data were evaluated by basic and extended indirect response models using ADAPT II. Total body weight-normalized free prednisolone oral clearance and apparent volume of distribution were higher in men compared with women, regardless of race (by 22% in whites and 40% in blacks for oral clearance, p < 0.01; by32% in whites and 38% in blacks for apparent volume of distribution, p < 0.01). The 50% inhibitory concentration (IC50) values for T-suppressor cell-trafficking inhibition were higher in whites than in blacks, regardless of sex (by 125% in men and 208% in women, p < 0.01). The IC50 or SC50 values for effects of prednisolone on cortisol secretion and T-helper lymphocyte or neutrophil trafficking were not statistically different between men and women, blacks and whites. The findings of this study suggest that there are some prednisolone PK/PD differences related to sex and race. However, these differences do not suggest the need for dosage adjustments, and additional experiments with repeat dosing are needed to fully evaluate the clinical implication of these findings.

The estrous cycle affects pseudorabies virus (PRV) infection of the CNS

Previous work had suggested that mucosal immunity may be affected by the stage of the estrous cycle. Here, susceptibility to a neurotropic virus infection at different stages of the estrous cycle was assessed in a rodent model after direct injection of the virus into visceral organs. In the first two experiments, female Sprague-Dawley rats were infected with pseudorabies virus (PRV, Bartha's K-strain) by injection into either the cervix or the kidney after monitoring their estrous cycle. After either 4- or 5-day survival period post-infection, the rats were euthanized by transcardially perfusion and peripheral and central nervous system tissues were removed for immunocytochemical staining. The number of infected neurons was counted in various regions. Statistical analysis revealed that: (1) the number of infected cells in the sympathetic or parasympathetic ganglion, or the dorsal root ganglia was not affected regardless of the stage of the estrous cycle after cervix injection with PRV; (2) in contrast, the number of infected neurons in the spinal cord was affected significantly by the stage of the estrous cycle during viral infection of the cervix; (3) after kidney infection, the number of infected neurons found within the spinal cord or dorsal root ganglia varied significantly across the estrous cycle. In both cases, animals infected in proestrus or estrus had fewer infected neurons than animals infected in diestrus I or diestrus II (proestrous and estrous animals had less than 20% of infected cells found in diestrus I or diestrus II rats). In the third experiment, older, persistent estrous or persistent diestrous rats were infected by kidney injection and given a 4-day survival period, prior to virus isolation from lower thoracic spinal cord. Animals in persistent estrous had significantly less virus per gram of tissue than the persistent diestrous rats. These data suggest that the CNS of animals in proestrus or estrus is less susceptible to PRV infection compared to animals in either diestrus I or diestrus II. Because estrogen replacement therapy is known to restore some immune functions during reproductive ageing, it is speculated that plasma estrogen levels modulate the central nervous system's susceptibility to viral infections.

A comparison of the inflammatory response to a polydimethylsiloxane implant in male and female Balb/c mice

The implantation of biomaterials elicits a host response that influences the long-term behavior of implanted medical devices. This foreign body response is governed by cells of the immune system. Because sexual dimorphism in the immune system is well-established, a comparative study of the foreign body response in male and female mice was initiated. Eight-week-old male and female Balb/c mice received two subcutaneous implants in the interscapular region of a smooth peroxide-catalyzed polydimethylsiloxane (PDMS) and were sacrificed at 2, 14, 42, 70, and 105 days after implantation (n = 6 per sex per time point). Controls for each time point underwent the surgical procedure but received no implant. Tissue from the implant or surgical site was fixed, processed, and paraffin-embedded for histopathological evaluation and immunohistochemical (IHC) staining for tumor necrosis factor-alpha TNF-alpha) and interleukin-1 beta (IL-1beta). In control animals, an inflammatory response was observed at 2 days that was decreased by 14 days and absent after 42 days. At 2 and 14 days after PDMS implantation, a mild to moderate inflammatory reaction was observed around implants. The peak response was seen at 14 days, and granulation tissue, composed primarily of fibroblasts, macrophages, and neutrophils, was first observed at this time. After 105 days, the implantation site was surrounded by mature connective tissue, which had minimal numbers of macrophages and neutrophils, with severity scores that did not differ significantly in males and females. The immunostaining for TNF-alpha and IL-1beta followed similar temporal patterns, with both reaching a peak at the two week time point and remaining elevated, compared to level of expression in the controls, throughout the 105 day observation period. Staining for both cytokines in the implanted animals was generally higher in females than in males, although this difference was significant only for IL-1beta. These results suggest subtle differences between males and females in the activity of peri-implant inflammatory cells.

Cytokines and bone loss in a 5-year longitudinal study--hormone replacement therapy suppresses serum soluble interleukin-6 receptor and increases interleukin-1-receptor antagonist: the Danish Osteoporosis Prevention Study

The proinflammatory cytokines interleukin-1 beta (IL-1 beta) and IL-6 may play a central role in the acceleration of postmenopausal bone loss, but observational studies have led to contradictory results. Estrogen-dependent changes in the production of IL-1 receptor antagonist (IL-1ra) and the soluble IL-6 receptor (sIL-6R) potentially modify cytokine bioactivity. We therefore assessed the impact of menopause and hormone replacement therapy (HRT) on cytokines and activity modifiers in serum within a 5-year longitudinal study. One hundred sixty perimenopausal women (age 50.1 +/- 2.8 years) were randomized to HRT or no treatment. Serum IL-6 increased with age (r = 0.16; p < 0.05), but cytokines did not correlate with baseline bone mineral density (BMD). HRT led to small increases in IL-1ra (p < 0.001) and IL-6 (p < 0.05), with a decrease in sIL-6R (p < 0.01) and no change in IL-1 beta. No changes were observed in the control group. IL-1ra was inversely correlated with bone loss at the ultradistal forearm (r = 0.29; p < 0.05) and to a lesser degree at the spine (r = 0.20; p = 0.09). In addition, there was a weak positive correlation between sIL-6R and bone loss at the ultradistal forearm (r = 0.26; p < 0.05). High IL-6 levels were associated with slower bone loss (spine r = 0.31, p < 0.01) and controlling for age did not diminish this association. The percent change in sIL-6R during HRT was correlated with the bone loss at the femoral neck (r = -0.29; p < 0.01) and weakly with bone loss in the spine (r = -0.16; p = 0.17). In conclusion, serum IL-1ra and sIL-6R are influenced by HRT and are associated with the rate of bone loss in perimenopausal women.

Understanding cytokines. Part II: Implications for nursing research and practice

Cytokines are small signaling proteins released from a variety of cells that influence virtually every aspect of growth and development and every host response to infection, injury, and inflammation. Because of their widespread and potent effects across the life span, cytokines without a doubt influence nursing research and practice. From physiological and adaptive effects of cytokines to cytokine-induced diseases, nurses and nursing care are involved. Part II of this review highlights a few of the many examples of cytokines functioning in response to infection and inflammation, during the processes of reproduction, and in a variety of pathophysiological states. Implications for nursing research and practice are emphasized.

Influence of the menstrual cycle on the LPS-induced cytokine response of monocytes

We previously observed a gender difference in the cytokine response of peripheral blood monocytes (PBM). The study was performed to find out whether the gender-related difference might be due to hormonal changes during the menstrual cycle in healthy premenopausal females. The release of tumour necrosis factor a (TNF-alpha) was reduced in the premenopausal females during the luteal phase compared to the follicular phase. Compared to the male controls the release of TNF-alpha and of interleukin 6 (IL-6) during the luteal phase was also diminished. In premenopausal females the concentration of estradiol in plasma correlated with the release of TNF-alpha and IL-6 during the luteal phase.

Modulation of IL-6 production during the menstrual cycle in vivo and in vitro

During the menstrual cycle (MC), premenopausal women experience changes in basal temperature and their physical condition and well-being. Premenopausal female patients with chronic inflammatory diseases demonstrate changes in disease activity during the MC. The study was initiated to explore reasons for these phenomena. The sex hormone-modulated lipopolysaccharide (LPS)-induced interleukin-6 (IL-6) secretion in a whole blood assay, serum IL-6 concentration, and serum sex hormone concentrations were studied throughout the MC in five healthy female subjects (median, 28 years; mean, 31.2+/-2.2 years, 26-38 years). Serum IL-6 concentration demonstrated a significant increase in the luteal phase of the MC and was elevated when serum dehydroepiandrosterone (DHEA) was low and vice versa. DHEA decreased LPS-induced IL-6 secretion at six of seven time points during the MC (DHEA, p = .047). In contrast, beta-estradiol and testosterone increased LPS-induced IL-6 secretion in six of seven time points during the MC (significant for testosterone, p = .005). The study demonstrates oscillation of serum IL-6 concentration during the MC and the marked MC-dependent modulation of IL-6 secretion by sex hormones. These mechanisms may be involved in the changes in the basal temperature, the general condition, and, in patients with chronic inflammatory diseases, of disease activity during the MC.

Cytokines inhibit sexual behavior in female rats: II. Prostaglandins mediate the suppressive effects of interleukin-1beta

The proinflammatory cytokine interleukin-1 (IL-1) induces several behavioral alterations that are characteristic of illness, such as anorexia and reduced locomotor and social activity. We have recently demonstrated that IL-1 inhibits sexual activity, motivation and attractivity in female, but not in male rats following either central or peripheral administration. In the present study we examined the involvement of prostaglandin (PG) synthesis in mediating IL-1-induced suppression of female sexual behavior. Administration of the cyclooxygenase blockers indomethacin or ibuprofen completely prevented IL-1-induced suppression of female sexual behavior, including the reduction in proceptive behavior, the lordosis response to a male's mounts, and the preference for a sexually active partner. In a subsequent study, ex-vivo release of hypothalamic PGE2 and the secretion of corticosterone (CS) were measured in males and estrous females following IL-1 administration. At the same time and dose of IL-1 administration that significantly reduced sexual behavior in female but not male rats, IL-1 produced a significant increase in PGE2 release in female, but not in male rats. In contrast, IL-1 induced a significant elevation of serum CS levels in males but not in females. These findings suggest that PG synthesis is involved in mediating the effects of IL-1 on female sexual behavior. Furthermore, differential secretion of PGs and CS may underlie the gender difference in the effects of IL-1 on sexual behavior.

Estrogen and lipopolysaccharide stimulation of prostacyclin production and the levels of cyclooxygenase and nitric oxide synthase in ovine uterine arteries

Several enzymes play a role in vasodilation, including cyclooxygenase, which converts arachidonic acid into prostaglandins, and nitric oxide synthase, which converts arginine to citrulline and yields nitric oxide. The effects of endogenous and exogenous estrogen and lipopolysaccharide on uterine artery production of prostacyclin, and levels of cyclooxygenase and nitric oxide synthase were examined. Uterine arteries collected from ewes during the follicular (Day -1 to 0, Day 0 = estrus) or luteal (Day 10) phase were treated in vitro with lipopolysaccharide. In addition, ovariectomized ewes were treated in vivo with estradiol-17beta (5 microg/kg; 120 min) or a vehicle control; arteries from the uteri were treated in vitro with lipopolysaccharide. After 24 h of lipopolysaccharide treatment, culture media were collected for measurement of 6-keto-prostaglandin F1alpha (the stable metabolite of prostacyclin). These uterine arteries were homogenized, and the level of cyclooxygenase and nitric oxide synthase was determined by Western analysis. Lipopolysaccharide stimulated (p < 0.02) prostacyclin production by uterine arteries from both follicular- and luteal-phase sheep although phase of the estrous cycle did not affect prostacyclin responses (p = 0.56) to lipopolysaccharide. In contrast, uterine arteries from ovariectomized sheep treated with estradiol-17beta produced more prostacyclin (p < 0.001) in response to lipopolysaccharide than did uterine arteries from ovariectomized sheep treated with the vehicle control. There was no effect of phase (follicular or luteal) of the estrous cycle on either cyclooxygenase-1 or -2 gene expression. Lipopolysaccharide increased (p = 0.0002) gene expression of cyclooxygenase-2, but not cyclooxygenase-1, in both follicular- and luteal-phase ewes, which was significantly correlated (r2 = 0.91, p = 0.003) with uterine artery production of prostacyclin. Uterine arteries from follicular-phase sheep expressed significantly more nitric oxide synthase-III after lipopolysaccharide exposure than did uterine arteries from luteal-phase ewes (p = 0.03). In contrast, nitric oxide synthase-II was not detected in uterine arteries after lipopolysaccharide exposure. These results suggest that estrogen plays a role in regulating uterine artery responses to lipopolysaccharide.

Adaptive interactions between cytokines and the hypothalamic-pituitary-gonadal axis

Circulating and tissue concentrations of pyrogenic cytokines, especially interleukin (IL)-1 beta, vary temporally through the menstrual cycle and pregnancy. The secretion of these cytokines in vitro by isolated human mononuclear cells is significantly influenced by exogenous gonadal steroids and gonadotropins. Reciprocally, cytokines influence gonadotropin secretion by the pituitary and steroidogenesis by the ovaries and testes. Several hypotheses have been advanced regarding the adaptive value of these interrelationships. Cytokine-induced synthesis of proteolytic enzymes and extracellular matrix proteins may be important for the tissue remodeling necessary for ovulation, implantation, and delivery. Tolerance of the fetal allograft may require downregulation of cytotoxic effector cells and reciprocal upregulation of humoral and nonspecific host defenses. The inhibitory influence of IL-1 beta on the luteinizing hormone surge may prevent inopportune conception, and the abortive influences of tumor necrosis factor-alpha and gamma interferon may terminate pregnancy during periods of infection.

Effects of interleukin-1 on sexual attractivity in a model of sickness behavior

Interleukin-1 (IL-1), a cytokine secreted by activated macrophages, inhibits sexual behavior in female but not male rats. The present study examined the effects of IL-1 on sexual attractiveness of the injected animal and on the sexual responses exhibited by its mating partner. In Experiment 1, a male rat was placed with an estrous female, injected with either IL-1 beta (2 or 10 micrograms/kg) or saline. Males exhibited more mounts and intromissions per ejaculation and longer ejaculation latencies with IL-1- than with saline-injected females. In a second experiment, a male was placed with two estrous females, one injected with IL-1 beta (5 micrograms/kg) and the other with saline. Males performed less sexual behavior and spent less time with the IL-1-injected female. In a third experiment, an estrous female was placed with two males, one injected with IL-1 beta (5 or 20 micrograms/kg) and the other with saline. IL-1 had no effect on the time spent by the female with each male, and only the high dose reduced proceptive (courtship) behavior. In conclusion, IL-1 administration to females reduces the quality of the sexual act, thus reducing the chances for conception during infection, which is associated with spontaneous abortion and abnormal development of the fetus. In males, the chances for reproduction are less affected by IL-1, possibly because reproduction during infection is not as risky in males as in females.

Immune alterations in male and female mice after 2-deoxy-D-glucose administration

Administration of 2-deoxy-D-glucose (2-DG) induces acute cellular glucoprivation. In the current study, we examined differences in immune parameters after 2-DG administration in both sexes. Male and female BDF1 mice were injected three times, 48 h apart, either with a saline solution (control group) or with 2-DG in saline (500 mg/kg). Two hours after the last injection, blood and spleens were collected. Plasma levels of interleukin-1beta, and interferon-gamma levels were measured. Additionally, the levels of the specific leukocyte antigens CD3, CD4, CD8, T cell receptor (TCR) alpha/beta, I-Ad, and H-2Ld/H-2Db were evaluated by flow cytometry on both blood and spleen cells. The blastogenic response of leukocytes from both tissues to mitogens was assessed. Levels of glucose, corticosterone, testosterone, progesterone, 17beta-estradiol, follicle-stimulating hormone, and luteinizing hormone were also determined. Increases in the percentage of cells bearing TCR alpha/beta and I-Ad in the blood and H-2Ld/H-2Db in the spleen were observed in the 2-DG-treated group for both sexes. In contrast, higher corticosterone and IL-1beta plasma concentrations, as well as higher percentages of splenocytes bearing TCR alpha/beta and I-Ad, and lower mitogen-induced proliferation of mature T splenocytes (79%) were observed in female but not in male mice injected with 2-DG compared with those injected with saline (p < 0.05). Taken together, these results suggest that female mice are more sensitive than male mice to immune alterations induced by 2-DG administration.

Different receptor mechanisms mediate the effects of endotoxin and interleukin-1 on female sexual behavior

Activation of the immune system by lipopolysaccharide (LPS) produces physiological, neuroendocrine and behavioral effects, some of which are mediated by cytokine production. We have previously shown that the cytokine interleukin-1 (IL-1) inhibits sexual behavior in female, but not male rats, while producing a comparable suppression of locomotion in both sexes. The present study examined the effects of LPS on sexual behavior and locomotion of male and female rats, and the involvement of IL-1 receptors in mediating the effects of IL-1 and LPS on females' behavior. Peripheral (i.p.) administration of LPS (50 or 250 microg/kg) significantly decreased sexual behavior in females, up to 6 h after administration, while it had no effect on male sexual behavior. However, locomotor activity, measured in the open-field test, was similarly reduced by LPS in both males and females. Pretreatment with the IL-1 receptor antagonist (IL-1ra) either i.p. (10 mg/kg) or intracerebroventricularly (i.c.v.) (50 microg/rat) did not prevent the inhibition of female sexual behavior and locomotion induced by either i.p. (50 microg/kg) or i.c.v. (200 or 400 ng/rat) administration of LPS, respectively. However, identical doses of IL-1ra significantly reversed the effects of IL-1beta, administered either i.p. (5 microg/kg) or i.c.v. (50 ng/rat), respectively. These results demonstrate that both LPS and IL-1beta produce marked inhibition of sexual behavior in female, but not in male rats. However, IL-1 receptors are not required for the effects of LPS on sexual behavior in female rats.

Gender differences in host defense mechanisms

Extensive studies in both humans and animals have shown that females express enhanced levels of immunoreactivity compared to males. Whereas this provides females with increased resistance to many types of infection, it also makes them more susceptible to autoimmune diseases. This review will focus on gender-related differences in non-specific host defense mechanisms with a particular emphasis on monocyte/macrophage function and a primary product of monocytes: interleukin-1 (IL-1). Immunomodulatory cytokines such as IL-1 are influenced by gender-sensitive hormones, and reciprocally, these cytokines influence gender-specific hormones and tissues. Patients with chronic fatigue syndrome (CFS) are predominantly women, therefore it may be useful to look toward gender-specific differences in immune function to find a key for this poorly understood syndrome.

Cytokines in the ovary: pathophysiology and potential for pharmacological intervention

The ovary and testis are sites for interaction between the endocrine and immune system via leukocytes and their secreted products, the cytokines. There are convincing data available to show that the gonads are sites of cytokine action and production. In the ovary, cytokines and leukocytes are intimately involved in follicular development, ovulation, and luteal function. A variety of clinical situations may be due to cytokine action in the gonads, and therapeutic manipulation of the immune system may affect reproductive function.