Serum leptin profiles in the normal menstrual cycles and gonadotropin treatment cycles

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.

Relationship of Serum Leptin and Reproductive Hormones in Unexplained Infertile and Fertile Females

OBJECTIVE

To investigate the relationship between serum leptin and reproductive hormones in females with unexplained infertility (UI).

METHODOLOGY

It was a case-control study conducted in the Gynecology and Obstetrics Department and Infertility Clinic, Jinnah Postgraduate Medical Center (JPMC), Karachi, Pakistan. A total of 235 primary infertile females with an unidentified cause of infertility were selected from the Infertility Clinics. The patients were excluded if they were found to have polycystic ovary syndrome, endometriosis, tubal blockage, irregular menstrual cycles, hyperthyroidism, hypothyroidism, hyperprolactinemia, hyperandrogenemia, fasting blood sugar >110 mg/dl, and male factor infertility. A total of 205 healthy, fertile females were selected from the general population. The blood samples of both groups were collected on the 12th and 21st day of their menstrual cycle. Serum leptin, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and E2 levels were measured. Statistical analysis was executed using the SPSS version 16 (SPSS Inc., Chicago, IL).

RESULTS

No significant difference was observed in leptin values of fertile and UI females, 37.110±1.19 vs. 35.321±0.901. In the preovulatory phase (12th day) of the cycle, infertile subjects with body mass index (BMI) <20 and 20-24.9 had significantly higher values for leptin (p<0.05), whereas, with an increase in BMI, leptin levels were reduced in these females. Leptin was reduced further in the luteal phase of infertile females with BMI 25-30, with a significantly lower value for FSH (p<0.005), LH (p<0.005), and estradiol (p<0.005. In infertile subjects, it correlated with estradiol (r=0.501, p<0.005), BMI (r=0.903, p<0.001), and progesterone (r=0.146, p<0.05).

CONCLUSION

Low levels of leptin observed to have an increase in the BMI of UI females were associated with a reduced estradiol and progesterone production in the luteal phase of the cycle.

Changes in serum leptin during phases of menstrual cycle of fertile women: relationship to age groups and fertility

BACKGROUND

It is established that serum level of leptin is affected by transitional phases of reproduction. It is also reported that the puberty is triggered when body fat and circulating levels of leptin exceed the critical thresholds, butthere is less focus on the serum level of leptin and its relationship with different phases of menstrual cycle and the fertility.

OBJECTIVES

The present study try to determines the serum concentration of leptin and fertility hormonesin the various phases of normal menstrual cycle of fertile women and compare any difference in serum concentration between age groups of 18-30 years and 31-41 years It is a well known fact that fertility start to decrease from age 31 years.

PATIENTS AND METHODS

A total of 118 healthy fertile women with normal menstrual cycle aged between 18-40, were divided into two age groups (n = 65) 18-30 years and (n = 53) 31-40 years. Serum concentrations of leptin, estradiol, progesterone, luteinising hormone (LH) and follicle-stimulating hormone (FSH) were measured on day1 (menstrual phase), day7 (proliferative/follicular phase), day14 (ovulatory phase), day21 (luteal phase) and day 28(secretory phase) of the menstrual cycle.

RESULTS

There was a significant increase (P < 0.05) in leptin levels on day 14 (12.75 + 5.8 ng/mL) and day 21 (12.91 + 3.2 ng/mL) for age group 18-30 years compared to day 14 (11.60 + 3.2 ng/mL) and day 21 (11.60 + 3.2 ng/mL) for age group 31-40 years. Leptin was positively correlated with FSH on day 14, with LH on day 7 and day 21; likewise, with progesterone on day 21 and day 28 and with estradiol on day 7 and day 14 for both age groups.

CONCLUSIONS

The serum leptin level was at the lowest level during the menstrual and secretory phase and the highest level was around the luteal phase. The significant increase ofleptin in the younger age group raise this question whether circulating leptin has any role to play in the age of pregnancy and fertility. Data in this study shows that leptin level was affected with increase in age; therefore changes in leptin level will affect fertility in this study suggest that there may be a relation between leptin levels and fertility.

Peritoneal fluid and serum leptin concentrations in women with primary infertility

AIM

Leptin is proposed to participate in the reproductive system of women by acting on either ovaries or hypothalamic-pituitary axis. The objective of the present study is to investigate the leptin concentrations in peritoneal fluid and serum samples of women diagnosed with primary infertility.

METHODS

A prospective study was carried out in women who underwent laparoscopy within the diagnostic process of primary infertility between January 2005 and January 2007. Leptin concentrations were determined in blood samples obtained before surgery and in peritoneal fluid samples collected during laparoscopy.

RESULTS

Peritoneal fluid was obtained from 112 subjects; 21 with unexplained infertility 28 with polycystic ovary syndrome (PCOS), 30 with bilateral tubal occlusion, and 33 with endometriosis. Subjects with PCOS have significantly higher body weights, BMI values and plasma leptin levels when compared to other study groups. Peritoneal fluid levels of leptin were significantly higher in the endometriosis group compared to other three study groups. A positive correlation was found between peritoneal fluid leptin levels and the endometriosis stage (r=0.51, P=0.01). However, plasma leptin levels were unrelated to the disease extent.

DISCUSSION

It might be hypothesized that leptin may be an active factor in the pathogenesis of PCOS and endometriosis, which are two major causes of primary infertility. A mild leptin deficiency in peritoneal environment may interrupt follicular development and ultimately lead to PCOS. Leptin has angiogenic and mitogenic properties, which trigger inflammatory cytokines and eventually result in the development of endometriosis implants. Significantly, higher levels of leptin in peritoneal environments of endometriosis subjects strongly imply the important role of this common pathology.

Serum leptin levels in women with uterine leiomyomas

OBJECTIVE

The purpose of this study was to examine the influence of leptin in women with uterine myoma.

MATERIALS AND METHODS

In this study, 38 women with myoma uteri and 30 normal women who applied to the Dr Zekai Tahir Burak Woman Health Research and Education Hospital's gynecology clinic were enrolled. Uterine leiomyomas were proved by pathology postoperatively. In all subjects, FSH, LH, E2, prolactin, hemoglobin, hematocrit, blood urea nitrogen, creatinine, fasting glucose, CA125, and leptin were examined, and body mass index (BMI) was calculated. Data were analyzed by Student's t test and Mann-Whitney U test.

RESULTS

Although leptin level was higher in the myomatic women (5.73 +/- 4.08 ng/mL) than in the normal women, there was no statistically significant difference (p = 0.303). Also, no statistical difference in the ratios of leptin/BMI was found in both groups. A significant correlation was found between high E2 level and myoma uteri (p = 0.021). Hemoglobin levels were significantly lower in the myomatic women (p = 0.044). When we compared the leptin levels according to BMI, leptin levels were higher in patients who had BMI > 30 (p = 0.02).

CONCLUSION

We did not find any significant difference in serum leptin levels between the two groups. But leptin may have an indirect role in the pathogenesis of uterine leiomyoma. So further research is needed to reveal the role of leptin in myoma uteri pathogenesis.

Effects of exogenous estradiol and progesterone on plasma concentrations of leptin in ewes in non-breeding season

Estradiol and progesterone may play a role in controlling leptin secretion by utilizing their receptors in adipocytes and the genomic mechanisms of the leptin gene. This study was conducted to evaluate the effects of exogenous sex steroids on the blood leptin concentrations in ewes in the non-breeding season. Multiparous ewes were fed to maintenance level for their live weights. Blood samples were collected at 12-h intervals from Days -3 to -1 to determine the basal leptin levels (pre-injection period). From Day 0 to Day 5 (injection period), blood sampling continued at 12-h intervals, and the ewes were injected intramuscularly at 24-h intervals with oil, 50 mg progesterone in oil, 1 mg of estradiol in oil, or both steroids in oil. Leptin was measured using a sensitive and specific radioimmunoassay based on recombinant bovine leptin. Overall, plasma concentrations of leptin were not affected by any of the steroid treatments, and there were no differences in the value of leptin between the pre-injection and injection periods among the 4 groups. Therefore, the exogenous estrogen and progesterone used in this study do not have a strong effect on the blood leptin concentrations of ewes in the non-breeding season.

Leptin in pregnancy: an update

Leptin influences satiety, adiposity, and metabolism and is associated with mechanisms regulating puberty onset, fertility, and pregnancy in various species. Maternal hyperleptinemia is a hallmark of mammalian pregnancy, although both the roles of leptin and the mechanisms regulating its synthesis appear to be taxa specific. In pregnant humans and nonhuman primates, leptin is produced by both maternal and fetal adipose tissues, as well as by the placental trophoblast. Specific receptors in the uterine endometrium, trophoblast, and fetus facilitate direct effects of the polypeptide on implantation, placental endocrine function, and conceptus development. A soluble isoform of the receptor may be responsible for inducing maternal leptin resistance during pregnancy and/or may facilitate the transplacental passage of leptin for the purpose of directly regulating fetal development. The steroid hormones are linked to the regulation of leptin and the leptin receptor and probably interact with other pregnancy-specific, serum-borne factors to regulate leptin dynamics during pregnancy. In addition to its effects on normal conceptus development, leptin is linked to mechanisms affecting a diverse array of pregnancy-specific pathologies that include preeclampsia, gestational diabetes, and intrauterine growth restriction. Association with these anomalies and with mechanisms pointing to a fetal origin for a range of conditions affecting the individual's health in adult life, such as obesity, diabetes mellitus, and cardiovascular disease, reiterate the need for continued research dedicated to elucidating leptin's roles and regulation throughout gestation.

The role of aromatase inhibitors in ameliorating deleterious effects of ovarian stimulation on outcome of infertility treatment

Clinical utilization of ovulation stimulation to facilitate the ability of a couple to conceive has not only provided a valuable therapeutic approach, but has also yielded extensive information on the physiology of ovarian follicular recruitment, endometrial receptivity and early embryo competency. One of the consequences of the use of fertility enhancing agents for ovarian stimulation has been the creation of a hyperestrogenic state, which may influence each of these parameters. Use of aromatase inhibitors reduces hyperestrogenism inevitably attained during ovarian stimulation. In addition, the adjunct use of aromatase inhibitors during ovarian stimulation reduces amount of gonadotropins required for optimum stimulation. The unique approach of reducing hyperestrogenism, as well as lowering amount of gonadotropins without affecting the number of mature ovarian follicles is an exciting strategy that could result in improvement in the treatment outcome by ameliorating the deleterious effects of the ovarian stimulation on follicular development, endometrial receptivity, as well as oocyte and embryo quality.

The relation of serum and follicular fluid leptin and ovarian steroid levels in response to induction of ovulation in in vitro fertilization cycles

OBJECTIVE

Leptin restores energy homeostasis and regulates appetite and body weight by communicating the energy status to the central nervous system. Although there is strong evidence that leptin affects reproduction, its role in the control of reproductive physiology is little understood.

STUDY DESIGN

We studied leptin concentrations in the serum and follicular fluid of 65 women undergoing ovarian hyperstimulation for in vitro fertilization (IVF). Fasting serum samples were collected (1) on the 3rd day of the cycle before IVF and (2) at the time of oocyte retrieval. Serum concentrations of leptin, estradiol (E2), progesterone, FSH, LH, prolactin, total testosterone, DHEA-SO4, and TSH and follicular fluid concentrations of leptin, E2, and progesterone were measured.

RESULTS

Serum leptin values increased on average by 66.4% over basal leptin levels on the day of oocyte pick-up (OPU). A positive correlation between leptin increase and body mass index was observed. The serum leptin level was similar to that in follicular fluid o the day of OPU. E2 levels increased 34.5-fold with controlled ovarian hyperstimulation. There was a negative correlation between the increase in leptin levels and in E2 levels (P <0.05) and in the number of oocytes harvested (P <0.05).

CONCLUSION

The significant increase in serum leptin levels during controlled ovarian hyperstimulation indicates a possible role of leptin in reproductive function. The increase in leptin levels is negatively correlated with ovarian response evaluated by E2 production and number of oocytes retrieved. This might be due to the reduced ovarian response through negative feedback of leptin to the ovaries at high levels.

Changes in serum leptin levels during GnRH agonist therapy

The purpose of the present study was to investigate changes in serum leptin levels during GnRH agonist therapy. Twenty regularly menstruating women with uterine leiomyomas were enrolled. These subjects were given GnRH agonist (leuprorelin acetate, 3.75 mg) monthly for 4 months. Serum leptin and estradiol (E2) levels were measured at the two time points of day 1 or 2 of the menstrual cycle and the end of GnRH agonist therapy. Weight, total body fat mass, percentage of body fat, and total body lean mass were measured by whole body scanning with dual-energy X-ray absorptiometry. The ratio of serum leptin levels to total body fat mass (leptin-fat mass ratio), and the ratio of serum leptin levels to total body lean mass (leptin-lean mass ratio) were calculated. All subjects became amenorrheic after the initial administration of GnRH agonist. Baseline E2 levels were 45.4 +/- 21.0 pg/mL, which significantly decreased after GnRH agonist therapy (13.3 +/- 4.2 pg/mL, p<0.01). Baseline leptin levels were 8.7 +/- 8.1 ng/mL, which did not differ from the values after 4 months of GnRH agonist administration (8.9 +/- 6.8 ng/mL). Total body fat mass significantly increased from 20.0 +/- 10.4 to 21.0 +/- 9.4 kg (p<0.05), while total body lean mass significantly decreased (34.5 +/- 4.2 kg to 33.3 +/- 3.9 kg, p<0.01). However, leptin-fat mass ratio after GnRH agonist therapy did not differ from the baseline values (0.39 +/- 0.16 ng/mL/kg vs 0.38 +/- 0.16 ng/mL/kg). Hypogonadism does not have a major impact on circulating leptin levels.

Effects of an 8-week weight-loss program on cardiovascular disease risk factors and regional body composition

OBJECTIVE

To determine the influence of weight loss on multiple cardiovascular disease (CVD) risk factors.

DESIGN

Overweight women (n = 12; mean 44.2% fat) and men (n = 10; mean 30.7% fat) participated in an 8 week weight-loss program that included dietary, exercise, multi-vitamin/mineral supplementation, and behavior modification components. Measurement of total and regional body composition assessed using dual energy X-ray absorptiometry (DEXA), circumferences and blood sampling for total cholesterol, LDL cholesterol, HDL cholesterol, triacylglycerols, homocysteine, insulin and leptin were performed before and after the weight loss intervention.

RESULTS

Subjects increased their physical activity and decreased their energy intake, resulting in a mean decrease in body mass of - 4.3 +/- 3.4 kg in women and -4.7 +/- 3.1 kg in men. Fat accounted for 88 and 58% of the decrease in body mass in men and women, respectively. Proportionally, men lost significantly more fat mass from the trunk region compared to women. Serum total and LDL cholesterol were significantly decreased in men (-11 and -14%, respectively) but not women (-3 and -3%, respectively) and there were no changes in HDL cholesterol and triacylglycerols. Serum leptin was significantly decreased (-36%) and highly correlated to fat mass (r= 0.839). There were no changes in serum insulin and plasma homocysteine.

CONCLUSIONS

These data indicate that short-term weight loss resulting from reducing percentage energy from fat, increasing physical activity and vitamin/mineral supplements including folic acid has a favorable effect on regional body composition and total and LDL cholesterol with minimal effects on HDL cholesterol, triacylglycerols, homocysteine and insulin and the effects are greater in men compared to women. Supplementation with folic acid or emphasis on folic acid-rich foods may be an important component of a weight loss program to prevent increases in homocysteine.

Leptin in obstetrics and gynecology: a review

Leptin, a recently described type-1 cytokine, is involved in cellular maturation and growth and appears to have a relationship to some obstetrical and gynecologic diseases. The MEDLINE database was accessed, and leptin-related articles published during the past 6 years were reviewed for their relevance to gynecologic and obstetrical diseases. The relationships between this cytokine and obesity, puberty, polycystic ovary syndrome, endometriosis, assisted fertility, and menopause are discussed. The role of leptin in fetal physiology and in normal and abnormal fetal growth as well as its role in diabetes, pregnancy, and pregnancy-induced hypertension are reviewed.

Leptin in pregnancy

Leptin is a polypeptide hormone that aids in the regulation of body weight and energy homeostasis and is linked to a variety of reproductive processes in both animals and humans. Thus, leptin may help regulate ovarian development and steroidogenesis and serve as either a primary signal initiating puberty or as a permissive regulator of sexual maturation. Perhaps significantly, peripheral leptin concentrations, adjusted for adiposity, are dramatically higher in females than in males throughout life. During primate pregnancy, maternal levels that arise from adipose stores and perhaps the placenta increase with advancing gestational age. Proposed physiological roles for leptin in pregnancy include the regulation of conceptus growth and development, fetal/placental angiogenesis, embryonic hematopoiesis, and hormone biosynthesis within the maternal-fetoplacental unit. The specific localization of both leptin and its receptor in the syncytiotrophoblast implies autocrine and/or paracrine relationships in this endocrinologically active tissue. Interactions of leptin with mechanisms regulating pre-eclampsia and maternal diabetes have also been suggested. Collectively, therefore, reports suggest that a better understanding of the regulation of leptin and its role(s) throughout gestation may eventually impact those causes of human perinatal morbidity and mortality that are exacerbated by intrauterine growth retardation, macrosomia, placental insufficiency, or prematurity.