Serum and follicular fluid leptin during in vitro fertilization: relationship among leptin increase, body fat mass, and reduced ovarian response

Obesity-Related Hypogonadism in Women

Obesity-related hypogonadotropic hypogonadism is a well-characterized condition in men (termed male obesity-related secondary hypogonadism; MOSH); however, an equivalent condition has not been as clearly described in women. The prevalence of polycystic ovary syndrome (PCOS) is known to increase with obesity, but PCOS is more typically characterized by increased gonadotropin-releasing hormone (GnRH) (and by proxy luteinizing hormone; LH) pulsatility, rather than by the reduced gonadotropin levels observed in MOSH. Notably, LH levels and LH pulse amplitude are reduced with obesity, both in women with and without PCOS, suggesting that an obesity-related secondary hypogonadism may also exist in women akin to MOSH in men. Herein, we examine the evidence for the existence of a putative non-PCOS "female obesity-related secondary hypogonadism" (FOSH). We précis possible underlying mechanisms for the occurrence of hypogonadism in this context and consider how such mechanisms differ from MOSH in men, and from PCOS in women without obesity. In this review, we consider relevant etiological factors that are altered in obesity and that could impact on GnRH pulsatility to ascertain whether they could contribute to obesity-related secondary hypogonadism including: anti-Müllerian hormone, androgen, insulin, fatty acid, adiponectin, and leptin. More precise phenotyping of hypogonadism in women with obesity could provide further validation for non-PCOS FOSH and preface the ability to define/investigate such a condition.

The effects of obesity and insulin dysregulation on mare reproduction, pregnancy, and foal health: a review

Obesity is a growing welfare concern in modern equine populations and predisposes horses to disturbances in energy metabolism such as insulin dysregulation. However, equine metabolic syndrome has only been recognized in recent decades. Functioning energy metabolism is pivotal to normal body homeostasis and affects essentially all organ systems, including reproduction. Previous literature suggests that obesity has an effect not only on the reproductive processes in mares but also on offspring health, predisposing the offspring to later-onset orthopedic and metabolic problems. This review focuses on the effects of obesity, insulin dysregulation and hyperinsulinemia on the reproductive functions of mares and the implications on foal health before and after birth. The points of interest are the cyclicity and ovarian function, uterine environment, gestation, the postpartum period, and the newborn foal. The aim is to review the current state of knowledge, and identify outstanding questions that could stimulate future research. This topic is important not only from the equine industry and production perspective but is also relevant for the welfare of future populations and individuals.

Role of adipokines in the ovarian function: Oogenesis and steroidogenesis

Adipokines are mainly produced by adipose tissue; however, their expression has been reported in other organs including female reproductive tissues. Therefore, adipokines have opened new avenues of research in female fertility. In this regard, studies reported different roles for certain adipokines in ovarian function, although the role of other recently identified adipokines is still controversial. It seems that adipokines are essential for normal ovarian function and their abnormal levels could be associated with ovarian-related disorders. The objective of this study is to review the available information regarding the role of adipokines in ovarian functions including follicular development, oogenesis and steroidogenesis and also their involvement in ovary-related disorders.

The role of diet in unexpected poor response to ovarian stimulation: a cross-sectional study

RESEARCH QUESTION

Is there an association between diet and poor ovarian response to ovarian stimulation in women with normal biomarkers of ovarian reserve?

DESIGN

Women eligible for IVF at an Academic Fertility Center were invited to participate in this prospective cross-sectional study. The main inclusion criteria were age 18-39 years, body mass index 18-25 kg/m², preserved ovarian reserve (antral follicle count 10-22 or anti-Müllerian hormone concentration 2-5 ng/ml) and a starting dose of gonadotrophins of 150-225 IU/day. Information on diet was obtained using a validated food frequency questionnaire. 'Unexpected poor ovarian response' was defined as the retrieval of three or fewer suitable oocytes. A logistic regression model was used to adjust for confounders.

RESULTS

Out of the 303 women enrolled in the study, 48 (16%) showed an unexpected poor ovarian response. The frequency of poor responders increased with increasing glycaemic load, carbohydrate intake and fibre intake. When comparing the third with the first tertile (reference), the adjusted odds ratios for these were 3.91 (95% confidence interval [CI] 1.11-13.83, P = 0.04), 4.78 (95% CI 1.23-18.51, P = 0.02) and 6.03 (95% CI 1.18-30.77, P = 0.07), respectively.

CONCLUSIONS

Elevated dietary glycaemic load as well as carbohydrate intake and fibre intake is significantly associated with unexpected poor ovarian response. Future interventional studies should clarify whether dietary modification might restore normal response.

Follicular fluid leptin as a marker for pregnancy outcomes in women undergoing IVF treatment: a systematic review and meta-analysis

Leptin is a hormone secreted mainly by the adipocytes with an essential role in the regulation of body weight. It acts on the reproductive axis at different sites, with stimulatory effects at the hypothalamus and pituitary and inhibitory interactions at the gonads. To investigate the influence of leptin on pregnancy outcomes in women undergoing IVF, we undertook a systematic review. A search of PubMed from 1966 to 2018 identified ten studies meeting the inclusion criteria. Outcomes were BMI, serum leptin level at hCG injection, serum and follicular fluid leptin level at the oocyte pick up, and serum 17β-oestradiol level at oocyte pick up time, oocytes retrieved and embryo transfer number. Results indicated that follicular fluid leptin concentrations at the oocyte pick up were significantly lower in women who became pregnant compared to those who did not (MD = -4.53 (ng/ml); 95% CI: -7.78, -1.78; p value < 0.006). In conclusion, elevated leptin concentrations in follicular fluid at oocyte pick up time is significantly associated with an adverse pregnancy outcome in women undergoing an IVF programme.

Effect of Body Weight on Metabolic Hormones and Fatty Acid Metabolism in Follicular Fluid of Women Undergoing In Vitro Fertilization: A Pilot Study

INTRODUCTION

Obesity is an epidemic affecting more than one-third of adults in the United States. Obese women experience decreased fertility, explained in part by oocyte quality. Since follicular fluid (FF) provides an important microenvironment for oocyte growth, we sought to evaluate the effect of increased body weight on FF levels of 11 metabolic hormones and fatty acid metabolism.

METHODS

The FF was collected from 25 women (10 normal weight, 10 overweight, and 5 obese) with diminished ovarian reserve undergoing in vitro fertilization (IVF) following a minimal stimulation protocol. Hormone levels were determined by multiplex immunoassay using the MAGPIX (Luminex, Austin, Texas) instrument. Fatty acid metabolites were determined using gas and ultra-high pressure liquid chromatography coupled with mass spectrometry.

RESULTS

Levels of hormones related to glucose and energy homeostasis and regulation of fat stores (insulin, glucagon, glucagon-like peptide-1, C-peptide, and leptin) were increased significantly in FF from obese women compared to FF from nonobese(normal weight and overweight) women. Interestingly, FF levels of branched-chain amino acids (BCAA) isoleucine, leucine, and valine as well as uric acid, isocaproic acid, butanoic acid, tyrosine, threonine, glycine, and methionine correlated positively with body mass index.

CONCLUSION

This pilot study demonstrates significant alterations in the FF milieu of obese women undergoing IVF, which may contribute to the decreased fecundity of obese women. Although the impact of this environment on oocyte and embryo development is not fully realized, these changes may also lead to imprinting at the genomic level and long-term sequelae on offspring.

Short-term effects of a hypocaloric diet with low glycemic index and low glycemic load on body adiposity, metabolic variables, ghrelin, leptin, and pregnancy rate in overweight and obese infertile women: a randomized controlled trial

BACKGROUND

Obesity is related to hormonal disorders that affect the reproductive system. Low-glycemic index (LGI) diets seem to exert a positive effect on weight loss and on metabolic changes that result from obesity.

OBJECTIVE

We investigated the effects of a hypocaloric diet with an LGI and low glycemic load on anthropometric and metabolic variables, ghrelin and leptin concentrations, and the pregnancy rate in overweight and obese infertile women who were undergoing in vitro fertilization (IVF).

DESIGN

The study was a randomized block-design controlled trial in which we analyzed 26 overweight or obese infertile women. Patients were assigned to a hypocaloric LGI-diet group or a control group and followed the protocol for 12 wk. Body weight, body mass index (BMI), percentage of body fat, glucose, insulin, homeostasis model assessment of insulin resistance, serum lipids, reproductive hormones, leptin, acylated ghrelin, number of oocytes retrieved in the IVF cycle, and pregnancy rate were determined.

RESULTS

There were greater reductions in body mass, BMI, percentage of body fat, waist:hip ratio, and leptin in the LGI-diet group than in the control group (P < 0.05). Despite a change of 18% in mean values, there was no significant increase in acylated ghrelin concentrations in the LGI group compared with the control group (P = 0.215). The LGI-diet group had 85.4% more oocytes retrieved than did the control group (7.75 ± 1.44 and 4.18 ± 0.87, respectively; P = 0.039) in the IVF cycle. Three patients (21.4%) in the LGI group experienced a spontaneous pregnancy during the follow-up, which generated 3 live births.

CONCLUSIONS

The hypocaloric LGI diet promoted a decrease in BMI, percentage of body fat, and leptin concentrations, which improved oocyte development and pregnancy rate. These results support the clinical recommendation to advise overweight and obese women to lose weight through a balanced diet before being submitted for treatment with assisted reproduction technologies. A hypocaloric diet combined with LGI foods seems to be beneficial for these patients, but additional studies are required before this treatment is recommended. This trial was registered at clinicaltrials.gov as NCT02416960.

Impact of maternal malnutrition during the periconceptional period on mammalian preimplantation embryo development

During episodes of undernutrition and overnutrition the mammalian preimplantation embryo undergoes molecular and metabolic adaptations to cope with nutrient deficits or excesses. Maternal adaptations also take place to keep a nutritional microenvironment favorable for oocyte development and embryo formation. This maternal-embryo communication takes place via several nutritional mediators. Although adaptive responses to malnutrition by both the mother and the embryo may ensure blastocyst formation, the resultant quality of the embryo can be compromised, leading to early pregnancy failure. Still, studies have shown that, although early embryonic mortality can be induced during malnutrition, the preimplantation embryo possesses an enormous plasticity that allows it to implant and achieve a full-term pregnancy under nutritional stress, even in extreme cases of malnutrition. This developmental strategy, however, may come with a price, as shown by the adverse developmental programming induced by even subtle nutritional challenges exerted exclusively during folliculogenesis and the preimplantation period, resulting in offspring with a higher risk of developing deleterious phenotypes in adulthood. Overall, current evidence indicates that malnutrition during the periconceptional period can induce cellular and molecular alterations in preimplantation embryos with repercussions for fertility and postnatal health.

Effects of female increased body mass index on in vitro fertilization cycles outcome

BACKGROUND

As being overweight can impair female spontaneous fertility or after assisted reproductive technology (ART) cycles, the aim of this study was to compare in vitro fertilization (IVF) outcome according to women's body mass index (BMI).

METHODS

Retrospective study conducted from 2006 to 2009 in the IVF unit of Nantes University Hospital, France. 582 patients undergoing standard infertility workup and controlled ovarian stimulation were categorized according to BMI into two groups: group 1: normal weight (20-24.9 kg/m(2); n=409) and group 2: overweight and obese (≥25 kg/m(2); n=149). Basal hormonal status, smoking habitus, infertility duration, IVF cycle parameters and outcome were recorded.

RESULTS

Basal LH, FSH and estradiol levels were higher in group 1 than group 2, but ovarian reserve markers were comparable across the two BMI groups. Higher doses of gonadotropins were required in group 2 to obtain equivalent ovarian response than in group 1. No difference was observed on ovarian response and embryonic parameters. Cycle outcome were not significantly different between both groups, but we found a strong trend towards increasing transfer cancellation and miscarriage rates in group 2.

CONCLUSION

Although overweight and obesity do not compromise ovarian stimulation results whenever adaptation of recombinant FSH doses is made, our data suggest an increased risk of cancellation transfer and miscarriage rate, leading to poorer IVF outcome.

An updated view of leptin on implantation and pregnancy: a review

The hormone leptin, which is thought to be primarily produced by adipose tissue, is a polypeptide that was initially characterized by its ability to regulate food intake and energy metabolism. Leptin appears to signal the status of body energy stores to the brain, resulting in the regulation of food intake and whole-body energy expenditure. Subsequently, it was recognized as a cytokine with a wide range of peripheral actions and is involved in the regulation of a number of physiological systems including reproduction. In the fed state, leptin circulates in the plasma in proportion to body adiposity in all species studied to date. However other factors such as sex, age, body mass index (BMI), sex steroids and pregnancy may also affect leptin levels in plasma. In pregnant mice and humans, the placenta is also a major site of leptin expression. Leptin circulates in biological fluids both as free protein and in a form that is bound to the soluble isoform of its receptor or other binding proteins such as one of the immunoglobulin superfamily members Siglec-6 (OB-BP1). Although the actions of leptin in the control of reproductive function are thought to be exerted mainly via the hypothalamic-pituitary-gonadal axis, there have also been reports of local direct effects of leptin at the peripheral level, however, these data appear contradictory. Therefore, there is a need to summarize the current status of research outcomes and analyze the possible reasons for differing results and thus provide researchers with new insight in designing experiments to investigate leptin effect on reproduction. Most importantly, our recent experimental data suggesting that reproductive performance is improved by decreasing concentrations of peripheral leptin was unexpected and cannot be explained by hypotheses drawn from the experiments of excessive exogenous leptin administration to normal animals or ob/ob mice.

Impact of obesity on endometrial blood flow in women without polycystic ovarian syndrome during intracytoplasmic sperm injection

BACKGROUND

Obesity may exert a negative effect on in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) treatment. However, the effect of obesity on the endometrium remains unknown. This study was designed to assess the effect of isolated body mass index (BMI) on endometrial blood supply in non-polycystic ovary syndrome (PCOS) women during ICSI by power Doppler Ultrasound.

METHODS

An observational prospective study was carried out. A total of 206 patients without PCOS were divided into 4 groups based on Chinese BMI classification (kg/m(2): underweight (BMI < 18.5), normal weight (18.5 less than or equal to BMI < 24), overweight (24 less than or equal to BMI < 28), and obese (BMI greater than or equal to 28). Endometrial thickness, endometrial pattern, endometrial spiral arterial resistance index (RI) and pulsatility index (PI) values and systolic/diastolic ratio (S/D) were assessed on the day of human chorionic gonadotropin administration.

RESULTS

Obese patients required more doses of gonadotrophin and longer stimulation duration than the normal weight patients (P < 0.05). Endometrial thickness and pattern were not statistically different between the 4 BMI subgroups (P > 0.05). Subendometrial blood flow was detected in 165 (80.1%) patients and spiral arterial PI was significantly higher in the obese group than in the normal weight and underweight groups (P < 0.05). All parameters of ICSI outcome were comparable, including pregnancy and miscarriage rates.

CONCLUSIONS

Obesity (BMI greater than or equal to 28 kg/m(2)) appears to exert a negative effect on endometrial and subendometrial blood flow based on the Chinese standard of obesity; however, it seems to have no significant effect on ICSI outcomes in non-PCOS women.

Ontogeny of the ovary in polycystic ovary syndrome

Activation of primordial follicles into the growing pool, selection of the dominant follicle, and its eventual ovulation require complex endocrine and metabolic interactions as well as intraovarian paracrine signals to coordinate granulosa cell proliferation, theca cell differentiation, and oocyte maturation. Early preantral follicle development relies mostly upon mesenchymal-epithelial cell interactions, intraovarian paracrine signals, and oocyte-secreted factors, whereas development of the antral follicle depends on circulating gonadotropins as well as locally derived regulators. In women with polycystic ovary syndrome (PCOS), ovarian hyperandrogenism, hyperinsulinemia from insulin resistance, and altered intrafollicular paracrine signaling perturb the activation, survival, growth, and selection of follicles, causing accumulation of small antral follicles within the periphery of the ovary, giving it a polycystic morphology. Altered adipocyte-ovarian interactions further compound these adverse events on follicle development and also can harm the oocyte, particularly in the presence of increased adiposity. Finally, endocrine antecedents of PCOS occur in female infants born to mothers with PCOS, which suggests that interactions between genes and the maternal-fetal hormonal environment may program ovarian function after birth.

The effects of GnRH analogs on serum and follicular fluid leptin levels and pregnancy outcomes in short protocols of assisted reproductive technology

OBJECTIVE

To determine serum and follicular leptin levels in patients using gonadotropin releasing hormone agonist and antagonist in Assisted Reproductive Technology short protocol cycles and to evaluate pregnancy outcomes.

MATERIAL AND METHODS

Patients randomly selected to join assisted reproductive technology cycles during February 2004-July 2004 were enrolled in this study. Group 1 consisted of 21 patients receiving r FSH+ GnRH agonists, whereas Group 2 consisted of 34 patients who received r FSH +GnRH antagonists. During the ovulation induction period 5 serum samples were collected (induction day 1, day 3 or antagonist starting day, human chorionic hormone day, oocyte pickup day, and twelfth day of embryo transfer). Follicular fluid samples were collected to be evaluated for leptin, estradiol, prolactin and luteinizing hormone.

RESULTS

There was no difference in age, basal FSH, basal LH, and basal E2 between groups. Serum leptin levels were similar in both groups. Also, when each group's serum leptin levels were evaluated according to the presence of pregnancy, there was no significant difference in both groups. When follicle leptin levels were evaluated according to the existence of pregnancy, in both groups the follicle leptin levels were lower in pregnant participants but this difference was not statistically significant. When obesity is defined as body mass index over 26.5, there is a correlation between obesity and leptin levels in Group 2.

CONCLUSION

Our results have shown that both agonists and antagonists have similar efficacy and effect in poor responder women. Leptin levels in either groups, whether pregnant or non-pregnant were not statistically different. This result shows the need for more studies on leptin in infertility.

Adipokines: new emerging roles in fertility and reproduction

Adipose tissue is a specialized endocrine and paracrine organ producing specific factors called adipokines. It is well known that adipokines balance is fundamental to prevent obesity, metabolic syndrome, and cardiovascular diseases. During the last years, new roles of adipokines have been emerging in the field of fertility and reproduction. Although the literature is still quite controversial, this review serves to resume current knowledge on this topic. Alterations in adipokine levels or in their mechanism of action are associated with fertility impairment and pregnancy diseases, as well as with obesity, metabolic syndrome, and cardiovascular diseases. Normal levels of adipokines are fundamental to maintain integrity of hypothalamus-pituitary-gonadal axis, regular ovulatory processes, successful embryo implantation, and physiologic pregnancy. More efforts are needed to understand the mechanisms and to the extent to which adipokine changes are involved in the impairment of fertility and pregnancy outcome, to find possible medical treatments.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians Learning Objectives: After completion of this educational activity, the obstetrician/gynecologist should be better able to demonstrate current knowledge in the research field of adipokines in fertility and reproduction; evaluate the central role of metabolism balance in good pregnancy outcome; and apply new perspectives of studies.

Women, weight, and fertility: the effect of body mass index on the outcome of superovulation/intrauterine insemination cycles

OBJECTIVE

To determine the fecundity of overweight and obese infertile women treated with gonadotropins and undergoing intrauterine insemination (IUI).

DESIGN

Retrospective study.

SETTING

Academic infertility clinic.

PATIENT(S)

Four hundred seventy-seven women undergoing 1,189 ovulation induction (OI)/IUI cycles stratified by body mass index (BMI).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

BMI groups were compared regarding the following: gonadotropin dose, duration of treatment, peak E(2), number of follicles (total, large, and medium size), E(2)/follicle, endometrial thickness, spontaneous abortion, and clinical and multiple pregnancy rates.

RESULT(S)

There was a significant trend toward higher medication requirements and lower E(2) levels with increasing BMI. BMI was inversely associated with [1] the E(2) level per produced preovulatory follicle and [2] the number of medium-size follicles. Furthermore, BMI was inversely associated with the number of medium, large, and total follicles divided by total FSH dose, suggesting that women with a higher BMI develop a lower number of medium and/or large follicles at a given total FSH dose. BMI was positively associated with endometrial thickness, and endometrial thickness was positively associated with pregnancy. Mean number of cycles required to conceive, clinical pregnancy, and spontaneous abortion rates did not differ significantly among the different BMI categories.

CONCLUSION(S)

Obese women require higher doses of medication and produce fewer follicles for a given dose, but once medication and response are adjusted to overcome the weight effect, the success of the treatment cycle is comparable to that of normal weight women.

The effect of pinealectomy, melatonin and leptin hormones on ovarian follicular development in female Syrian hamsters (Mesocricetus auratus)

We studied the effects of melatonin and leptin hormones on ovarian follicular development in intact and pinealectomized female Syrian hamsters. We first monitored the oestrous cycle of the hamsters by the vaginal smear samples throughout a ten day period to start the injections simultaneously in all groups and performed saline, melatonin and leptin hormone injection groups for both control and pinealectomized hamsters. Then the injections were applied for four days starting the oestrus phase of the cycle and the ovaries were removed for preparation of histological analysis. We measured the diameters and the numbers of the follicles and we classified the follicles according to the number of the granulosa cell layer. Leptin hormone injection increased melatonin hormone injection decreased the number and the diameter of the follicles. The stimulating effect of the leptin hormone was more pronounced in the pinealectomized group. The results of the present study indicate that the removal of the pineal gland and leptin hormone administration are playing a stimulatory while melatonin hormone administration is playing an inhibitory role on the follicular development in female Syrian hamsters.

Expression of leptin long-form receptor mRNA in luteinized granulosa cells of obese women with polycystic ovary syndrome

To investigate the expression of mRNA of leptin long-form receptor (OB-Rb) in luteinized granulosa cells of obese women with polycystic ovary syndrome (PCOS), and to determine the role of leptin in the physiopathology of PCOS, luteinized granulosa cells were collected from the follicle fluid of 10 obese women who met the diagnostic criteria for PCOS and their BMI was equal to or greater than 25 kg/m(2), and at the same time, granulosa cells were collected from 10 normal women undergoing IVF-ET who served as the control group. Some luteinized granulosa cells were taken from normal women for in-vitro culture, into which human leptin of different concentrations was added (0, 10, 100 and 1000 ng/mL). After stimulation with leptin for 48 h, RT-PCR was employed for the detection of the expression of OB-RLmRNA in the luteinized granulosa cells. Our results showed that the level of OB-RLmRNA in luteinized granulosa cells of obese PCOS women was higher than those in the control (P<0.05). In luteinized granulosa cells cultured in vitro and stimulated by human leptin for 48 h, the level of OB-RLmRNA was higher than those without leptin stimulation (P<0.01), and when leptin concentration was at 100 ng/mL, and the level of OB-R(L)mRNA reached a peak. It is concluded that in obese PCOS women, the level of serum leptin is increased, which promotes the expression of OB-R(L) in luteinized granulosa cells and increases the sensitivity of the granulosa cells to leptin. Leptin may contribute to anovulation in obese women with PCOS.

Assessment of the predictive value of follicular fluid insulin, leptin and adiponectin in assisted reproductive cycles

PURPOSE

To assess the correlation of intrafollicular insulin, leptin and adiponectin levels with assisted reproductive technologies (ART) outcome.

METHODS

This was a retrospective study of 46 patients undergoing in vitro fertilisation/intracytoplasmic sperm injection. Follicular fluid (FF) samples collected at oocyte retrieval were assayed for insulin, leptin and adiponectin levels using enzyme-linked immunosorbent assay, and correlations with ART outcome were analysed.

RESULTS

There was no significant correlation between intrafollicular insulin, leptin and adiponectin levels. There was a significant difference in the concentration of insulin (P = 0.007), but not leptin or adiponectin, between pregnant (n = 20) and non-pregnant (n = 26) cycles. Only two pregnancies was observed in the 12 cycles in which the concentration of insulin was greater than 7 mU/l in FF, while 18 pregnancies was observed in the 34 cycles in which the concentration of insulin was less than 7 mU/l (P = 0.043). The significantly high concentration of insulin in FF was observed in non-pregnant cycles of patients with polycystic ovary syndrome (PCOS).

CONCLUSIONS

Our results suggest the possible involvement of intrafollicular insulin in folliculogenesis. Insulin resistance-related substances may affect the reproductive process in patients with PCOS.

Infertility treatment outcome in sub groups of obese population

BACKGROUND

Obesity is a common disorder with a negative impact on IVF treatment outcome. It is not clear whether morbidly obese women (BMI >= 35 kg/m2) respond to treatment differently as compared to obese women (BMI = 30-34.9 kg/m2) in IVF. Our aim was to compare the outcome of IVF or ICSI treatments in obese patients to that in morbidly obese patients.

METHODS

This retrospective cohort study was conducted in a tertiary care centre. Patients inclusion criteria were as follows; BMI >or= 30, age 20-40 years old, first cycle IVF/ICSI treatment with primary infertility and long follicular pituitary down regulation protocol.

RESULTS

A total of 406 obese patients (group A) and 141 morbidly obese patients (group B) satisfied the inclusion criteria. Average BMI was 32.1 +/- 1.38 kg/m2 for group A versus 37.7 +/- 2.99 kg/m2 for group B. Patient age, cause of infertility, duration of stimulation, fertilization rate, and number of transferred embryos were similar in both groups. Compared to group A, group B had fewer medium size and mature follicles (14 vs. 16), fewer oocytes collected (7 vs. 9) and required higher doses of HMG (46.2 vs. 38.5 amps). There was also a higher cancellation rate in group B (28.3% vs. 19%) and lower clinical pregnancy rate per started cycle (19.9% vs. 28.6%).

CONCLUSION

In a homogenous infertile and obese patient population stratified according to their BMI, morbid obesity is associated with unfavorable IVF/ICSI cycle outcome as evidenced by lower pregnancy rates. It is recommended that morbidly obese patients undergo appropriate counseling before the initiation of this expensive and invasive therapy.

Reproductive endocrinology and clinical aspects of obesity in women

Obesity is a growing worldwide problem and is associated with a wide range of adverse effects on the female reproductive system. The endocrinological changes in obesity that may cause these adverse effects are complex and include changes in circulating adipokines and sex steroids as well as insulin resistance. Considerable evidence suggests an adverse effect of obesity on the risk of miscarriage and other maternal and fetal complications. Obese patients are also more prone to infertility. The most important single method to improve reproductive performance in obese women is weight loss that can be achieved with lifestyle changes and diet. Antiobesity drugs may also be used and, in severe cases, bariatric surgery.

Association of serum and follicular fluid leptin concentrations with granulosa cell phosphorylated signal transducer and activator of transcription 3 expression in fertile patients with polycystic ovarian syndrome

OBJECTIVE

Our objective was to evaluate whether polycystic ovarian syndrome (PCOS)-associated infertility is related to alterations of leptin, leptin receptor (Ob-R), and the phosphorylated signal transducer and activator of transcription 3 (p-STAT3)/suppressor of cytokine signal 3 (SOCS3) system in the ovary.

DESIGN AND SETTING

A case-control study was conducted in a university hospital.

PATIENTS

Thirty-one infertile PCOS women with oligoovulation plus polycystic ovarian morphology and 79 infertile women with tubal blockage (control) participated in the study. The subjects were stratified according to in vitro fertilization outcomes: successful and failed subgroups.

METHODS

Serum and follicular fluid (FF) leptin levels were measured with ELISA. RT-PCR and Western blotting were performed to assess expression of mRNA encoding leptin and Ob-R and proteins of p-STAT3 and SOCS3 in granulosa cells (GCs).

RESULTS

Leptin levels in serum and FF of PCOS women were significantly higher than those of control (P < 0.01). There were no significant differences in expression of leptin mRNA and short and long Ob-Rs between PCOS and control (P > 0.05). The p-STAT3 level was decreased in PCOS compared with control (P < 0.01), whereas SOCS3 remained significantly unchanged (P > 0.05). Further analysis showed that serum and FF leptin levels were significantly higher, whereas p-STAT3 in GCs was lower in the failed subgroup of PCOS than those in the successful subgroup of PCOS (P < 0.05).

CONCLUSION

Hyperleptinemia and high FF leptin are important pathologies of PCOS with infertility. Lower levels of p-STAT3 in GCs may be related to ovarian leptin resistance and fecundity in PCOS women. Relatively high serum and FF leptin and low p-STAT3 in GCs may account for decreased fertilization, implantation, and pregnancy rates of in vitro fertilization in PCOS women.

The utility of serum leptin and follicular fluid leptin, estradiol, and progesterone levels during an in vitro fertilization cycle

PURPOSE

To prospectively evaluate serum and follicular fluid leptin, estradiol, and progesterone levels during in vitro fertilization.

METHODS

Prospective observational study measuring serum levels at six points during the IVF cycle and follicular fluid at the time of retrieval.

RESULTS

Serum leptin and estradiol levels both significantly increased for the individual patients during the IVF stimulation process. None of the leptin levels differed based on pregnancy outcome. BMI significantly correlated with all leptin levels. Follicular fluid estradiol correlated with serum estradiol only in pregnant patients (r = 0.97, p<0.01) and was unrelated in non-pregnant patients (r=-0.15, p=0.81).

CONCLUSION

Serum and follicular leptin levels are highly correlated. Leptin levels increase during the IVF cycle and vary between patients based on maternal BMI, but do not correlate with other serum hormone levels or pregnancy outcome. Pregnancy outcome success was reflected in the relationship between follicular fluid and serum levels of estradiol, independent of leptin levels.

Intra-follicular leptin concentration as a predictive factor for in vitro oocyte fertilization in assisted reproductive techniques

BACKGROUND

Granulosa-cells are able to produce and store leptin, suggesting that this hormone is locally involved in the regulation of follicular growth. In this study, the role of follicular fluid (FF) leptin concentration in predicting oocyte fertilization and embryo quality was evaluated in 35 normogonadotrophic women undergoing controlled ovarian stimulation (COS) for assisted reproductive techniques.

MATERIALS AND METHODS

Leptin concentration was measured in 47 consecutively collected FF in which a mature oocyte had been found during the ovum pick-up. Embryos deriving from fertilized oocytes were submitted to quality scoring systems.

RESULTS

Mean leptin concentration was significantly higher in FF whose oocytes showed 2 pronuclei (no. 25) when compared with those with no evidence of fertilization (no. 22) at the 16-18 h check (26.0+/-6.1 vs 15.3+/-10.6 ng/ml, respectively, p<0.01). Follicular mean diameters were similar in the two groups (21.4+/-3.4 and 21.0+/-5.1 mm, respectively). Logistic regression analysis identified FF leptin levels as the best predictive parameter for oocyte fertilization (p<0.001). When receiving operating characteristics curve was employed, a FF leptin concentration of 20.25 ng/ml was the most reliable cut-off in predicting fertilization of oocytes. FF with leptin concentrations higher than this value (no. 27) had an oocyte fertilization rate of 85.7%. In contrast, FF levels < or =20.25 ng/ml (no. 20) were associated with a rate of 16.7% (p<0.05). No correlation emerged between FF leptin and the score attributed to 15 valuable embryos at the zygote stage (r=-0.01) and at 48 h after insemination (r=0.1).

CONCLUSIONS

FF leptin levels are a better predictor of oocyte fertilization success rates than follicular diameter. These results underline the relevance of FF variables in developing methods for oocyte selection.

Interactions of the hormones leptin, ghrelin, adiponectin, resistin, and PYY3-36 with the reproductive system

OBJECTIVE

To summarize the effects of novel hormones (leptin, ghrelin, adiponectin, resistin, and PYY3-36) secreted from adipose tissue and the gastrointestinal tract that have been discovered to exert different effects on several reproductive functions, such as the hypothalamic-pituitary-gonadal axis, embryo development, implantation physiology, and clinically relevant conditions.

DESIGN

A MEDLINE computer search was performed to identify relevant articles.

RESULT(S)

Leptin and ghrelin exert important roles on body weight regulation, eating behavior, and reproduction, acting on the central nervous system and target reproductive organs. As a marker of adequate nutritional stores, these hormones may act on the central nervous system to initiate the complex process of puberty and maintain normal reproductive function. In addition, leptin and ghrelin and their receptors are involved in reproductive events such as gonadal function, embryo development, and embryo-endometrial interaction.

CONCLUSION(S)

Leptin and ghrelin and other adipose tissue-secreted hormones have significant effects on reproduction. Acting through the brain, these hormones may serve as links between adipose tissue and the reproductive system to supply and regulate energy needs for normal reproduction and pregnancy. Future studies are needed to further clarify the role of these hormones in reproductive events and other related gynecological conditions.

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.

Environmental and occupational factors affecting fertility and IVF success

Reproductive function has been shown to be sensitive to changes in the physical, psychosocial and chemical environments. Although reproductive effects of occupational exposure to hazardous chemicals have been well documented in the literature, the potential effects of chemical contaminants at levels representative of contemporary exposures in the general population are much less certain. Evidence for adverse effects of exposure to environmental contaminants is more conclusive among the lower animals than for humans where considerable controversy remains. In addition to potential reproductive hazards of exposure to environmental contaminants, there is also evidence for adverse reproductive effects of the physical and psychosocial environments. In this review we focus on the difficulties involved in linking exposure to putative hazardous substances in environmental and occupational settings to adverse reproductive outcomes, especially success of IVF procedures. We highlight the plausibility of adverse events through animal and cell studies and the application of these results to the interpretation of human data. We consider both the male and female partners since it is essentially their combined contributions of gametes which may be affected by chemicals, which lead to successful outcomes.

Leptin and soluble leptin receptor in follicular fluid

PURPOSE

Previous studies suggest that follicular fluid leptin levels predict successful assisted reproduction. The relationship between intrafollicular leptin and the soluble leptin receptor, ovarian hormones, and oocyte quality was examined to determine potential factors contributing to this finding.

METHODS

Follicular fluid leptin, soluble leptin receptor, hormones, and oocyte quality were examined in 84 individual follicles from 30 women undergoing in vitro fertilization.

RESULTS

Follicular fluid leptin and soluble leptin receptor levels correlated inversely with each other (r = -0.354; p = 0.001). Follicular fluid leptin levels correlated with intrafollicular estradiol (r = 0.42; p < 0.001), progesterone (r = 0.48; p < 0.001), and androstenedione (r = 0.49; p < 0.001), whereas soluble leptin receptor levels correlated with activin (r = 0.38; p < 0.001) and follistatin (r = 0.35; p < 0.002). There was no relationship between follicular fluid leptin or soluble leptin receptor levels and pretreatment serum hormone levels, stimulated serum estradiol, follicle number, oocyte quality, fertilization, or embryo grade.

CONCLUSION

The data demonstrate that leptin and the soluble leptin receptor are highly interrelated with each other and with other intrafollicular hormones, but not with markers of oocyte quality, fertilization, or embryo grade.

Serum leptin concentrations in patients with severe ovarian hyperstimulation syndrome during in vitro fertilization–embryo transfer treatment

OBJECTIVE

To investigate the changes in serum leptin concentration in the conception cycle of severe ovarian hyperstimulation syndrome (OHSS).

DESIGN

Prospective longitudinal study of 66 IVF-ET cycles between May 2000 and June 2002.

SETTING

Infertility outpatient clinic at a Japanese medical school.

PATIENT(S)

Infertile patients undergoing IVF-ET cycles at the infertility outpatient clinic were divided into three groups consisting of group 1 (conception-cycle patients with severe OHSS, n = 9), and group 2 (conception cycle, non-OHSS, n = 28), and group 3 (nonconception cycle, non-OHSS, n = 29).

INTERVENTION(S)

Blood samples were collected at five different periods. Period I, on the first day of ovarian stimulation with FSH; period II, at hCG administration before oocyte retrieval; period III, 7 days after oocyte retrieval; period IV, 14 days after oocyte retrieval; and period V, 21 days after oocyte retrieval.

MAIN OUTCOME MEASURE(S)

Serum leptin concentration.

RESULT(S)

The serum leptin concentration was low in the OHSS group compared with that of the non-OHSS groups in all serum samples, with significant levels at periods III (vs. groups 2 and 3; P<.05) and IV (vs. group 3; P<.01). A twofold increase of leptin concentration from period I to period II (P<.05) was observed in all groups.

CONCLUSION(S)

The change pattern in serum leptin concentration might provide a great contribution to the pathophysiology development of OHSS patients during assisted reproductive treatment.

Serum pattern of circulating free leptin, bound leptin, and soluble leptin receptor in the physiological menstrual cycle

OBJECTIVE

To investigate the serum pattern of free leptin, bound leptin, and soluble leptin receptor throughout the physiological menstrual cycle.

DESIGN

Prospective observational study.

SETTING

Tertiary care center for gynecological endocrinology and reproductive medicine and a university research laboratory.

PATIENT(S)

Thirty regularly cycling volunteers (age, 29 +/- 4.2 years).

INTERVENTION(S)

Blood sampling was performed at different phases (early and mid follicular phase, preovulatory phase, and early and late luteal phase) of three consecutive menstrual cycles; each phase of the menstrual cycle was investigated twice.

MAIN OUTCOME MEASURE(S)

Free leptin, bound leptin, soluble leptin receptor, LH, E(2), P, vaginal ultrasound.

RESULT(S)

A peak of serum free leptin levels was found in the late luteal phase followed by a significant drop in the early follicular phase and again by a continuous increase up to the next luteal peak. There were no significant alterations in serum bound leptin and soluble leptin receptor levels.

CONCLUSION(S)

The present study shows that there are significant circacyclic fluctuations of free leptin levels with the highest concentrations in the late luteal phase and the lowest levels in the early follicular phase, which suggests that circulating free leptin is up-regulated by the C(21)-steroid (P). Circulating bound leptin and soluble leptin receptor are not altered by the cyclic hormone status. The significant rise of the leptin bioequivalent, free leptin, in the late luteal phase might be of importance for the luteal-follicular and the luteal-preimplantatory functional shift.

In VitroFertilization: Angiogenic, Proliferative, and Apoptotic Factors in the Follicular Fluid

The studies reported investigated the concentrations of angiogenic, proliferative, and apoptotic factors in the follicular fluid (FF) of individual follicles, aspirated from women undergoing controlled ovarian hyperstimulation using a long protocol for IVF treatment. Furthermore, the association of the concentrations of the preceding factors with oocyte maturity was studied. Vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), angiogenin, tissue polypeptide specific antigen (TPS), and soluble Fas (sFas) were all found in the FF of all follicles examined. Moreover, from the angiogenic factors only angiogenin concentrations, and from the apoptotic factors sFas concentrations (the soluble form expressing rather an antiapoptotic function), were positively associated with oocyte maturity, possibly indicating angiogenin's biological role beyond neovascularization and a lower apoptotic rate allowing oocytes to mature. Last, the abundant expression of TPS in FF may be indicative of intense cell proliferation, in cases of ovarian stimulation.

Vascular endothelial growth factor and leptin: regulation in human cumulus cells and in follicles

BACKGROUND

The factors that determine oocyte competency are poorly understood. It is believed that angiogenic factors are crucial. Modulation of these factors is therefore a central consideration. The adjacent association of cumulus cells to oocytes gives these cells a particular importance in relation to oocyte behavior. We report the effects of gonadotropins on the secretion of VEGF and leptin from cumulus cells; and the concentrations of the proteins in follicular fluid and their relationship to fertilization of oocytes in vitro.

METHODS

The subjects were women undergoing intracytoplasmic sperm injection (ICSI). Oocytes and follicular fluid were collected. Leptin and vascular endothelial growth factor (VEGF) concentrations in incubation supernatants and follicular fluid and leptin in cell lysates were measured. Fertilization of corresponding oocytes were noted. In the present study, cells from individual follicles were incubated, as well as pooled cells from a woman.

RESULTS

For the first time we demonstrated that VEGF release by human cumulus cells was modulated by gonadotropins in a dose-related, time-dependent manner, but no leptin was detected in either the supernatants after cumulus cell incubations or in cell lysates. Mean leptin levels were similar whether from follicles associated with eggs that were fertilized (14.4 +/- 1.1 ng/ml, mean +/- SEM) or not (12.4 +/- 1.1 ng/ml). Mean VEGF levels were also similar (11.1 +/- 1.2 ng/ml; 12.8 +/- 1.3 ng/ml). A greater proportion of VEGF in follicles was derived from follicular activities, compared with transfer from other physiological compartments, than leptin.

CONCLUSIONS

Whereas it is possible that VEGF is part of the gonadotropin-mediated network that regulates development of the oocyte, leptin may not be produced in significant quantities by cumulus cells or be related to oocyte competency.

Three-dimensional power Doppler imaging of ovarian stromal blood flow in women with endometriosis undergoing in vitro fertilization

OBJECTIVE

The aims of this retrospective study were to investigate whether the quantification of ovarian stromal blood flow and/or leptin concentration are predictive of in vitro fertilization (IVF) outcomes in women after laparoscopic ovarian cystectomy for large endometriomas.

METHODS

Twenty-two women undergoing IVF after laparoscopic surgery for ovarian endometriomas (> 6 cm) comprised the study group. Twenty-six women with tubal factor infertility constituted the control group. Ovarian stromal blood flow was evaluated by three-dimensional (3D) power Doppler ultrasound imaging using virtual organ computer-aided analysis (VOCAL( trade mark )). Serum and follicular fluid (FF) leptin concentrations were quantified using an enzyme-linked immunosorbent assay kit.

RESULTS

There were significantly decreased ovarian stromal blood flow parameters (including vascularization index, flow index (FI), and vascularization flow index) in the endometriosis group without an evident difference in total ovarian volume on the day of human chorionic gonadotropin. The value of FF leptin demonstrated a negative correlation with ovarian stromal FI in the control group, but there was a loss of this effect in the endometriosis group.

CONCLUSIONS

Quantification of ovarian stromal blood flow by 3D power Doppler ultrasound in women with endometriosis may provide an important prognostic indicator in those undergoing IVF.

Leptin in pregnancy

Leptin is a 16-kDa polypeptide, encoded in humans by the LEP gene. This protein is probably involved in the regulation of ovarian function, oocyte maturation and embryo development, and in the implantation process. During pregnancy, leptin is produced in the placenta; its values increase in the maternal blood particularly in the second trimester and decline postpartum. Leptin levels may be abnormally high in pregnancies complicated by conditions such as diabetes mellitus and pre-eclampsia. The role of leptin in fetal physiology has not been clarified, although cord blood values correlate significantly with birth weight. It is expected that further research will provide new insight into the physiological importance of leptin in the pregnant woman and fetus.

Leptin affects pregnancy outcome of in vitro fertilization and steroidogenesis of human granulosa cells

PURPOSE

This study was to examine the serum leptin levels in the prediction of pregnancy outcomes in women receiving ovarian hyperstimulation. Effect of leptin on the steroidogenesis was evaluated for granulosa cell (GC) culture in vitro.

METHOD

Serum levels of leptin and estradiol were measured on Day 2, the time of hCG administration and oocyte retrieval in 50 women undergoing long-course GnRH agonist ovarian hyperstimulation. The production of estrogen and progesterone in granulosa cell culture were detected after administration of leptin at the absence or presence of FSH 1 mIU.

RESULTS

Leptin levels at the time of hCG injection were significantly lower in the pregnant women than in those without pregnancy. Estradiol concentrations were not correlated with leptin levels during the time of hCG injection and oocyte retrieval. High leptin concentration suppressed both basal estradiol and progesterone productions in GC. Leptin in high doses suppressed estradiol production, but did not alter progesterone production of GC in the presence of FSH.

CONCLUSIONS

Serum leptin levels may be predictive of IVF pregnancy outcome with the effect on intraovarian progesterone/estradiol ratio during the follicular phase. Significantly low serum leptin levels were noted in the pregnant women than in the nonpregnant women.

Baseline non-fasting serum leptin concentration to body mass index ratio is predictive of IVF outcomes

BACKGROUND

The present study was designed to determine whether circulating leptin concentrations and/or body mass index (BMI) in women undergoing IVF are predictive of outcomes.

METHODS

IVF cycle outcomes, e.g. fertilization, embryo development, implantation, pregnancy, were analysed relative to baseline (i.e. day gonadotrophin stimulation was initiated) non-fasting serum leptin concentrations and BMI.

RESULTS

Serum leptin concentrations correlated with BMI (r = 0.739, P < 0.0001) as expected. Multiple logistic regression analyses showed correlation between serum leptin and pregnancy success (likelihood ratio = 5.198, P < 0.05), but there was no association between pregnancy and BMI. However, the serum leptin to BMI ratio was more strongly correlated (likelihood ratio = 7.258, P < 0.01) with pregnancy success than was leptin alone. Moreover, women with a low leptin:BMI ratio (< or =0.3) had significantly more superior quality embryos on day 3 post-retrieval (2.5 versus 1.4, P < 0.05, Kruskal-Wallis) and a greater implantation rate (26.7 versus 13.2%, P < 0.025, chi(2)) than women with a high leptin:BMI ratio (> or =0.7).

CONCLUSIONS

The leptin:BMI ratio appears to be highly predictive of IVF success. Elevated leptin concentrations, particularly relative to BMI, may negatively impact fertility by assisted reproduction, possibly through direct ovarian actions resulting in impaired oocyte quality and/or early embryo development.

Leptin during assisted reproductive cycles: the effect of ovarian stimulation and of very early pregnancy

Leptin may have a role in human reproduction. The impact of IVF and of very early pregnancy on serum leptin concentrations was studied in 66 infertile patients, of whom 19 became pregnant. Ovarian suppression was accompanied by a fall in leptin concentrations (21 +/- 4%, mean +/- SE; P < 0.01) from the mid-luteal phase, and ovarian stimulation by a rise (76 +/- 8%; P < 0.0001) from suppression. The mid-luteal concentration of leptin after stimulation was 28 +/- 7% higher than that during the preceding normal cycle (P < 0.001). Concentrations of leptin and oestradiol were related before treatment, at ovarian suppression and at 8 days after oocyte retrieval. In addition, the rises in leptin and oestradiol concentrations during stimulation were correlated, but only in those patients who became pregnant (r = 0.69; P = 0.001). Women with a successful pregnancy had higher concentrations of leptin (18.7 +/- 4.8 microg/l) at 12 days after embryo transfer than those who had miscarriages (10.0 +/- 1.9 microg/l; P < 0.001), or those failing to become pregnant (11.6 +/- 1.2 microg/l; P < 0.0001). We concluded that leptin concentrations are influenced by ovarian function and that the relationship between leptin and oestrogen (but not a single leptin concentration), may be an important factor for the outcome of IVF.

Leptin and the pituitary

Although leptin was originally viewed as an antiobesity hormone, it is now evident that it may have more pleiotropic actions. Experiments in rodents have shown that leptin activates the sympathetic nervous system, is involved in regulation of blood pressure, hematopoiesis, immune function, angiogenesis and brain, bone and pituitary development. Some biological effects expected based on observations in rodents, have so far not been seen in humans. Thus due to species differences in the role of leptin it is difficult to translate the data from rodents to human physiology. Hypothalamus is the primary brain site targeted by circulating leptin, secreted by fat cells. Leptin receptor has homology to members of class I cytokine receptor family, which may imply similarities in molecular events engaged by cytokines and leptin. In view of its cytokine-like properties it is likely that leptin produced and secreted outside of fat tissue i.e. in other tissues (CNS, pituitary, ovary, placenta, etc), is a paracrine regulator. Leptin receptor isoforms, long-signaling and short-nonsignaling, have been recently localized in human pituitaries. This opens the possibility of a direct action of leptin on the pituitary. However this appears to be quite complex and is species dependent. Leptin can be synthesized by normal and tumorous pituitary cells. Leptin protein expression in pituitary adenomas is decreased compared to that in normal pituitaries. Colocalization studies with leptin and anterior pituitary cells showed that 70% of ACTH cells are positive for leptin, 21% of GH cells, 29% of LH cells, 33% of FSH cells, 32% of TSH cells, 64% folliculo-stellate cells whereas very few PRL cells were positive (3%). Leptin is stored in secretory granules and secretory cells retain leptin in granules until stimulated. This follows a different secretory pathway than in adipocytes where upon synthesis leptin is immediately released. Question to be raised is does the pituitary contribute to the body leptin pool or is its action predominantly paracrine/autocrine? Clinically based evidence from studies performed in patients harboring different functional pituitary tumors causing a state of hormonal hypersecretion (acromegaly, prolactinomas, Cushing's disease) or hypopituitarism (due to non-functioning pituitary adenomas), are in favor of a paracrine/autocrine role of the pituitary leptin. Most of the studies have shown that the link between leptin, body composition and hormones of the pituitary is indirect. Thus changes in levels of circulating leptin are most likely due to changes in the metabolic and hormonal milieu during the chronic course of the disease or chronic treatment. Furthermore, circadian rhythm of leptin, its pulsatility and gender difference are preserved in hypopituitarism as well as in patients with functional pituitary adenomas implying that intact hypothalamic-pituitary function is not essential for leptin's circadian rhythm.

Leptin and maternal growth during adolescent pregnancy

BACKGROUND

Maternal growth on the basis of knee height occurs in nearly 50% of pregnant teenagers and is associated with greater gestational weight gain and accrual of subcutaneous fat in the mother but lower fetal growth compared with nongrowing teenagers and mature pregnant women.

OBJECTIVE

The objective of this study was to determine whether leptin is a biomarker for continued maternal growth.

DESIGN

Leptin concentrations were measured in 162 growing and nongrowing teenage gravidas (aged </=18 y) and in mature gravidas (aged 19-29 y) from the Camden Study at 2 time points during pregnancy and 1 time point postpartum.

RESULTS

Growing teenagers had leptin concentrations that increased with gestation and were higher at 28 wk gestation and postpartum than in nongrowing teenagers and mature gravidas. The differences were related to a leptin surge between entry into the study (16.9 wk) and week 28, primarily in still-growing gravidas. Leptin-surge quartiles were associated with higher knee-height velocity and weight gain, increased skinfold thicknesses in late pregnancy (28 wk) and early postpartum (4-6 wk), and changes in postpartum weight and body mass index. For the highest quartile, low birth weight increased >5-fold, fetal growth restriction increased >6-fold, and infant birth weight decreased by approximately 200 g. Gravidas who developed pregnancy-induced hypertension showed a different pattern-higher leptin concentrations at entry and week 28, no difference in the leptin surge, and no postpartum difference in leptin concentration.

CONCLUSION

A leptin surge by week 28 appears to mark reduced mobilization of maternal fat stores that is associated with maternal growth on the basis of knee height during adolescent pregnancy.

The decrease in luteinizing hormone secretion in response to weight reduction is inversely related to the severity of insulin resistance in overweight women

Controversial effects of weight reduction on gonadotropin secretion in obesity have been reported. As a result of pulsatility, single serum samples or frequent sampling studies are somewhat limited with regard to monitoring LH and FSH concentrations. We studied follicular phase nocturnal urinary (nu) LH and FSH secretion and glucose metabolism (150-min euglycemic hyperinsulinemic clamp) during 1 menstrual cycle/30-day period before and after weight reduction in 10 severely overweight infertility patients (age, 29 +/- 3.1 yr; body mass index, 37.1 +/- 3.3 kg/m2; +/-SEM). A 6-week very low calorie diet was followed by a 4-week normocaloric period. The urinary LH and FSH results reported represent samples taken 12 to 2 days before the LH surge, or 10 consecutive samples in the case of amenorrhea. We observed a decrease of 8% (P < 0.001) in percent body fat mass and a 5% (P < 0.005) reduction in waist to hip ratio. Mean nu-LH decreased by 45% [6.06 +/- 1.05 (+/-SEM) to 3.22 +/- 0.71 IU/L], whereas mean nu-FSH remained unchanged. Insulin-stimulated glucose uptake increased by 41% (P < 0.01), which was accounted for by a significant increase in nonoxidative glucose disposal (P = 0.003). Serum sex hormone-binding globulin concentrations increased by 39% (P < 0.01), and insulin-like growth factor (IGF)-binding protein-1 (IGFBP-1) levels increased by 46% (P < 0.05). Fasting serum insulin concentrations decreased by 38%, those of leptin by 37%, those of androstenedione by 32%, those of testosterone by 20% (all P < 0.01), and those of dehydroepiandrosterone sulfate by 13% (P < 0.05). The percent change in nu-LH correlated negatively with glucose uptake (r = -0.76; P < 0.01) and the increase in serum sex hormone-binding globulin (r = -0.85; P < 0.005) and positively with the percent change in waist to hip ratio (r = 0.79; P < 0.01). The absolute nu-LH levels after weight reduction correlated significantly with fasting insulin concentrations (r = 0.88; P < 0.001) and negatively with glucose uptake (r = -0.67; P < 0.05). No significant relationships were found between absolute levels or changes in nu-LH concentrations and leptin, IGF-I, IGFBP-3, or IGFBP-1 concentrations. Our findings suggest that weight reduction with a very low calorie diet results in a decrease in nu-LH concentrations, a reduction in the LH/FSH ratio, and FSH predominance favoring folliculogenesis. The decrease in LH concentrations is inversely related to the severity of insulin resistance. It is possible that the decrease in LH secretion with weight reduction is more dependent on the absolute levels of insulin sensitivity than on the degree of general adiposity.