Reduction of cardiovascular events in patients with cardiovascular disease with the CV-polypill: a retrospective and propensity score matching study

Background

Previous clinical trials suggested that a strategy based on a cardiovascular (CV) polypill improves risk factor control and reduces the incidence of CV events. The CNIC-Polyill (aspirin (ASA) 100mg, atorvastatin 20/40mg (or simvastatin 40mg) and ramipril 2,5–10mg) has shown to improve adherence and risk factors control.

Methods

The NEPTUNO study is a retrospective, non-interventional analysis of an anonymized medical history dataset in the BIG-PAC administrative database in the years 2015–2018. Patients at age ≥18 years with previous CV disease were allocated in four different cohorts according to their therapy: CNIC-polypill containing ASA 100mg, R 2.5/5/10mg and A 20/40mg (1:case cohort), identical mono-components (ASA,R,A) (C2), equipotent medication (ASA 100mg, simvastatin 40/80mg or rosuvastatin 5/10mg, enalapril 5–20mg or valsartan 40–160mg) (C3) and usual care (C4) (control cohorts) and were followed for 2 years. To ensure comparability of the study cohorts, a propensity score matching (PSM) was performed. The primary endpoint was the incidence first major cardiovascular event (MACE) including: myocardial infarction, angina, ischemic stroke, transitory ischemic attack, peripheral artery disease and CV mortality.

Results

8,946 patients were recruited. After the PSM, 4 well-balanced cohorts of 1,614 patients were obtained. The mean age was 63.3 years and 60.4% were men. Cohort 1 (Case cohort, CNIC-polypill) compared with cohorts 2, 3 and 4 showed a significant reduction in MACEs (19.8% vs. 23.3%, 25.5% and 26.8%; p<0.001), respectively although the CV death rate (8.1% vs. 8.1%, 8.9% and 9.2%; p=0.357) did not show differences. The hazard ratio (HR) for a MACE in the CV polypill cohort vs cohort 2 was 0.761 (IC95%; 0.657–0.881), p=0.001; vs Cohort 3 was 0.821 (IC95%; 0.714–0.944), p=0.006 and vs. Cohort 4 was 0.834 (IC95%; 0.716–0,950), p=0.008. Time to the event was also longer in the CV-polypill cohort compared the other 3 cohorts (274.8 days vs 249.2 days; 226.4 days and 217 days; p<0.001). There was a significant greater reduction in the case cohort vs the 3 control cohorts in the absolute levels of all the analyzed lipidic variables (LDL (−19.6 vs. −12.9, −12.3 and −9.1 mg/dL; p<0.001), triglycerides (−67.5 vs. −59.9, −56.1 and −54.4 mg/dL; p<0.001)) and in reduction of blood pressure (PAS (−14.1 vs. −11.7, −10.4 and −10.4 mmHg; p<0.001) and PAD (−4.5 vs −2.5, −2.1, −1.2 mmHg; p<0.001)). Higher persistence to treatment in the CNIC- polypill cohort (72.1% vs. 62. 2%, 60.0% and 54.2%; p<0.001) was also found.

Conclusion

This study shows the reduction of clinical events by the CNIC-polypill in a large population of real-life patients. In spite of the retrospective design of this study, the results of our analysis support the use of a CV-polypill in secondary prevention of cardiovascular events. These results need to be confirmed by prospective randomized clinical trials with major clinical outcomes.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Ferrer International Figure 1

Cost-effectiveness of the CNIC-polypill strategy for the secondary prevention of CV disease in male and female patients with established coronary heart disease based on improved risk factor control

Background

The burden of CV disease is a health and economic challenge to societies that is expected to grow in future years due to an increased prevalence in CV risk factors. Adequate management and appropriate therapy positively modify risk factors and, consequently, improve outcomes and cost-effectiveness of care. The CNIC-polypill has demonstrated in real-life, clinical effectiveness studies, its superiority over monocomponents in improving the lipidic parameters and in reduction of blood pressure in secondary CV prevention patients.

Purpose

To assess the cost-effectiveness of the CNIC-polypill (acetylsalicylic acid 100mg, atorvastatin 20/40mg, ramipril 2.5/5/10mg) compared to usual care with individual monocomponents for the secondary prevention of CV events in patients with a history of coronary heart disease (CHD) based on control of CV risk factors.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke, death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) based on changes in TC (10,1% reduction), HDL-c (7.4% increment) and SBP (2.6% reduction) obtained from the NEPTUNO* – a real-life, clinical effectiveness study conducted in Spain – was set for Portugal (base case). The probability of transition between health states was based on the SMART risk equation (S0, t=10= 0.8107). Cost-effectiveness was calculated for a hypothetical population (n=1,000) that replicated the characteristics of the population in the proACS registry, comprised of Portuguese patients with previous CHD. Systematic reviews identified epidemiological, costs, utility and mortality data. Outcomes were costs (€, 2020), life years (LY) and quality adjusted LY (QALY) gained.

Results

In patients with a history of CHD, the incremental cost of the CNIC-polypill strategy reaches €365,527, while preventing 35 recurrent CHD events and 17 subsequent strokes. In women and men with previous CHD, the incremental cost reaches €392,529 and €354,444 respectively while preventing recurrent 47 and 30 CHD events and 19 and 16 subsequent strokes respectively. The ICER is €5,130/LY gained for the overall population, €5,768/LY gained for women and €4,884/LY gained for men. The ICUR is €5,332/QALY gained in total, €5,817/QALY gained for women and €5,137/QALY gained for men. Assuming a willingness-to-pay (WTP) threshold of €30,000/QALY gained, there is 76.1% chances in total, 75.8% in women and 76.9% in men for the CNIC-polypill to be cost-effective and 27.8% chances overall, 27.7% in women and 25.5% in men of it being cost saving compared to usual care.

Conclusion

The CNIC-polypill seems to be a cost-effective strategy in men and women compared to usual care with monocomponents for the secondary prevention of CV disease based on improved control of risk factors. A larger reduction in the number of recurrent events is seen in women compared to men at a slightly higher cost.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Ferrer International S.A. Base case resultsProbabilistic sensitivity analysis

The real-world cost and health resource utilization associated to the CNIC-polypill compared to usual care

Background

Cardiovascular (CV) polypills have been defined as scalable strategies for CV prevention. Nonetheless, their impact on health systems from an economic perspective has been questioned. The NEPTUNO study has evaluated the effectiveness, the healthcare resources utilization (HRU) and the economic impact of the CNIC-polypill - aspirin (ASA) 100mg, atorvastatin (A) 20/40mg and ramipril (R) 2,5/5/10mg – compared to usual care in a real-life clinical setting in Spain.

Methods

The NEPTUNO study is a retrospective, non-interventional analysis of an anonymized medical history dataset covering patients contained in the BIG-PAC administrative database in the years 2015–2018. Patients at age ≥18 years with medical history of previous CV disease were allocated in 4 different cohorts according to their therapy: (1) CNIC-polypill (case cohort), (2) identical mono-components (ASA,R,A), (3) equipotent medication and (4) usual care (control cohorts) and were followed for 2 years. To ensure comparability the cohorts a propensity score matching was performed. Direct all-cause HRU, including inpatient stay, outpatient visits, emergency room visits, rehabilitation, testing and medical treatment, were registered. Total direct medical costs were computed based on unit costs (€, 2020) assigned to each HRU item and were expressed on a per patient (PP) basis. Indirect costs where estimated based on registered productivity loss and the interprofessional average salary.

Results

8,946 patients were recruited. After PSM, each of the four study cohorts consisted of 1,614 patients. There was acceptable comparability between the study cohorts (balance). The mean age was 63.3 years and 60.4% were men. Cohort 1 compared with the control cohorts 2, 3 and 4 showed a significant reduction in HRU on a per patient average for all items (table), specifically in visits to primary care (16.6 vs. 18.7, 18.9 and 21.0; p<0.001), visits to specialists (5.0 vs. 6.2, 6.5 and 7.3; p<0.001), percentage of patients hospitalized (16.5% vs. 19.8%, 21.9% and 24.0%; p<0.001) and days of hospitalization (2.3 vs. 3.4, 3.7 and 4.0; p<0.001), respectively. The total cost per patient with the CNIC-Polypill compared to monotherapy, equivalents and other treatments, corrected for covariates (ANCOVA), was significantly lower (€4,668 vs. €5,587, €5,682 and €6,016; p<0.001), representing a 16.5%, 17.8% and 22.4% reduction in total costs, respectively. Differences were also observed in healthcare costs, while in non-healthcare costs (loss of labor productivity) the differences were not significative (table).

Conclusion(s)

The results of our analysis demonstrate that the use of the CNIC-polypill results in a significantly lower HRU compared to control cohorts as well as a significantly lower total cost and direct medical costs. This data could support the sustainability and scalability of the polypill strategy.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Unrestricted grant from Ferrer Lab, Spain

Usefulness of carotid and femoral plaque burden quantification by 3-dimensional vascular ultrasound for cardiovascular risk assessment in the cardiovascular disease prevention unit

Introduction

Subclinical atherosclerosis improves cardiovascular risk assessment and is considered a risk modifier in individuals at borderline-to-intermediate estimated risk by clinical risk scores.

Purpose

We seek to propose a new decision algorithm for statin allocation based on the quantification of carotid and/or femoral atherosclerosis burden by novel 3-dimensional vascular ultrasound (3DVUS) and to explore its potential additive value when used in combination with conventional risk evaluation.

Methods

We conducted an observational study in all outpatients without previous history of cardiovascular events assessed in the Cardiovascular Disease Prevention Unit during 2017–2020. Cardiovascular risk was assessed with the ACC/AHA 10-year atherosclerotic cardiovascular disease (ASCVD) risk algorithm to establish the indication for initiating statin therapy following current clinical guidelines. All patients underwent 3DVUS evaluation for carotid plaque burden (CPB) calculated as the sum of all plaque volumes present in bilateral carotid arteries. Femoral 3DVUS evaluation was included later in the study protocol. Global plaque burden (GPB) was calculated in patients with both carotid and femoral 3DVUS as the sum of all plaque volumes present in bilateral carotid and femoral arteries. Carotid and global plaque burden was classified as high, moderate and low if a patient presented a percentile (p) >75, p50–75 and p<50, respectively, based on the age and sex-adjusted reference values reported by PESA study (1). We determined the percentage of patients reclassified for considering (p>75) or discouraging (p<50) statin therapy over clinical recommendation.

Results

One hundred sixty-three patients (age 51±8 years; 72,4% men; 10y-ASCVD 5,9%±4,8%) were included, being the most frequent reason for referral the presence of metabolic syndrome (37%), followed by intermediate or indeterminate estimated CV risk (33%), one markedly elevated single risk factor (15%) and family history of early CVD (13%). 10y-ASCVD score classified 80 (49%) patients as low-risk without recommendation for initiating statins, 18 (11%) as high-risk indicating statin therapy and 65 (40%) patients that needed clinical-patient risk discussion. Among patients under risk discussion, the CPB percentile re-stratified 51 (78%) of them, recommending statins in 26 (40%) and discouraging statins in 25 (38%). In addition, CPB re-stratified 24 (30%) low-risk patients to recommend statins. A sub-group of 114 patients additionally underwent femoral 3DVUS, and calculated GPB led to similar results of patient re-stratification (Figure).

Conclusions

Quantification of 3D atherosclerosis burden and its percentile would re-stratify a significant number of patients with intermediate risk, becoming a potentially useful tool for clinical decision making. In addition, it possibly improves the detection of low-risk patients who would benefit from statin therapy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Dr. Lόpez-Melgar has received a grant from the Spanish Society of Cardiology “Proyecto de investigaciόn traslacional en Cardiología 2020” Patient re-stratification with CPB/GPB

Clinical characteristics and outcomes of 1,331 patients with COVID-19: HM Spanish Cohort

OBJECTIVE

Spain is one of the European countries most affected by the COVID-19 pandemic. Epidemiologic studies are warranted to improve the disease understanding, evaluate the care procedure and prepare for futures waves. The aim of the study was to describe epidemiologic characteristics associated with hospitalized patients with COVID-19.

METHODS

This real-world, observational, multicenter and retrospective study screened all consecutive patients admitted to 8 Spanish private hospitals. Inclusion criteria: hospitalized adults (age≥18 years old) with clinically and radiologically findings compatible with COVID-19 disease from March 1st to April 5th, 2020. Exclusion criteria: patients presenting negative PCR for SARS-CoV-2 during the first 7 days from hospital admission, transfer to a hospital not belonging to the HM consortium, lack of data and discharge against medical advice in emergency departments.

RESULTS

One thousand and three hundred thirty-one COVID-19 patients (medium age 66.9 years old; males n= 841, medium length of hospital stayed 8 days, non-survivors n=233) were analyzed. One hundred and fifteen were admitted to intensive care unit (medium length of stay 16 days, invasive mechanical ventilation n= 95, septic shock n= 37 and renal replacement therapy n= 17). Age, male gender, leukocytes, platelets, oxygen saturation, chronic therapy with steroids and treatment with hydroxychloroquine/azithromycin were independent factors associated with mortality. The proportion of patients that survive and received tocilizumab and steroids were lesser and higher respectively than those that die, but their association was not significant.

CONCLUSIONS

Overall crude mortality rate was 17.5%, rising up to 36.5% in the subgroup of patients that were admitted to the intensive care unit. Seven factors impact in hospital mortality. No immunomodulatory intervention were associated with in-hospital mortality.

Cost-effectiveness of a cardiovascular polypill strategy (aspirin, atorvastatin, ramipril) for the secondary prevention of cardiovascular disease based on real life improvement in risk factor control

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Ferrer Internacional

Background

The cardiovascular (CV) polypill has consistently demonstrated cost-effectives in decreasing the risk of CV disease in patients in secondary prevention. Previous pharmacoeconomic studies addressed improvements in adherence as a driver of health gains. This economic assessment focuses on the implications of improved control of risk factors with the polypill as observed in clinical practice.

Purpose

To assess the cost-effectiveness of a fixed-dose combination polypill (ASA 100mg, atorvastatin 20/40mg, ramipril 2.5/5/10mg) strategy for the secondary prevention of CV and cerebrovascular events in adults with a history of coronary heart disease (CHD) or stroke compared to usual care with monocomponents.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke, death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) based on changes in CV risk factors (total cholesterol, 18.3% reduction; high density lipoprotein cholesterol, 2.1% increment; systolic blood pressure, 11.46% reduction) obtained from a real-life effectiveness study was set for Portugal. The probability of transition between health states was based on the SMART risk equation. Cost-effectiveness was calculated for two cohorts (n = 1,000) of secondary prevention patients with previous CHD or stroke. Systematic reviews, Portuguese registries, mortality tables and official reports were searched to identify effectiveness, epidemiological, costs and utility data. Outcomes were costs (€, 2020) per life year (LY) and Quality Adjusted LY (QALY) gained. One-way (OWA) and probabilistic (PSA) sensitivity analyses tested consistency. Assumptions were validated by experts.

Results

In the CHD cohort, the incremental cost-effectiveness ratio for the polypill strategy (ICER) is 2,402 €/LY and the incremental cost-utility ratio (ICUR) is 2,328 €/QALY. Incremental cost reaches 278,927 € (polypill, 13,198,506 €; monocomponents: 12,919,579 €) with less subsequent CV events (552.31 vs 641.88) and CV deaths (102.4 vs 118.68). Assuming a willingness-to-pay (WTP) threshold of 30.000 €/QALY gained, the PSA shows a 81.4% probability for the polypill to be cost-effective and 39.1% chances to be costs saving compared to usual care. In the stroke cohort, the ICER is 386 €/LY and the ICUR is 553 €/QALY. Incremental costs are 34,178 € (polypill, 10,138,807 €; monocomponents: 10,104,629 €) with less subsequent CV events (481.99 vs 564.50) and CV deaths (101.00 vs. 117.23) with the polypill. There is a 75.9% probability for the polypill to be cost-effective and 49.5% chances to be costs saving.

Conclusion

The CV polypill is a cost-effective secondary prevention strategy compared to usual care with monocomponents. Its ICER is well below acceptable thresholds in both CV and cerebrovascular disease patients. It reduces the number of recurrent events at a moderately higher cost compared to monocomponents.

How consistent are cost-effectiveness estimates of a cardiovascular polypill strategy for the secondary prevention of cardiovascular disease across different cardiovascular risk equations?

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Ferre Internacional

Background

Risk equations (RE) are crucial to individualise estimates and properly adjust preventive treatments in patients with previous cardiovascular (CV) disease. RE are also routinely incorporated into health economic assessments but it is unknown if the cost-effectiveness results vary according to the RE applied.

Purpose

To determine the cost-effectiveness of a CV polypill (ASA 100mg, atorvastatin 20/40mg and ramipril 2.5/5/10mg) strategy compared to usual practice of combining monocomponents in the prevention of recurrent events in patients with previous coronary heart disease (CHD) or stroke applying two different CV RE: SMART and FRAMINGHAM, respectively.

Methods

A Markov cost-effectiveness model (1-year cycles; 4 health states: stable disease, subsequent CHD, subsequent stroke; death; payer perspective; direct medical costs; lifetime horizon; 4% discount rate) was developed for Portugal. Transition probability between health states was based on the SMART RE and an adaptation for secondary CV prevention of the FRAMINGHAM RE, respectively. Cost-effectiveness was calculated for a mixed cohort of secondary prevention patients (weighed post-CHD: 57.9%; post-stroke: 42.1%). Systematic literature reviews, Portuguese registries, mortality tables and official reports ware used to identify effectiveness, epidemiological, costs and utility data. Outcomes were costs (€, 2020) per life year (LY) and Quality Adjusted Life Year (QALY) gained. One-way (OWA) and probabilistic (PSA) sensitivity analyses tested the consistency of results. Assumptions were validated by experts.

Results

Applying the SMART RE, the incremental cost-effectiveness ratio (ICER) is 1,555€/LY gained and the incremental cost-utility ratio (ICUR) is 1,785€/QALY gained for the polypill strategy. The incremental costs of adopting the polypill strategy are 171,378€. Recurrent CV events (550.68 vs 642.13) and CV deaths (106.05 vs 122.81) are also less frequent with the polypill strategy compared with monocomponents. Assuming a willingness-to-pay (WTP) threshold of 30.000 €/QALY gained, there is a 77.80% probability for the polypill strategy to be cost-effective and 43.00% chances to be costs saving when used in a mixed cardiovascular and cerebrovascular disease population. Applying the FRAMINGHAM RE, the ICER is 998€/LY gained and the ICUR is 1,242€/QALY. The incremental costs amount 175,122€. Recurrent CV events (452.66 vs 563.48) and CV deaths (104.77 vs 127.32) are less frequent with the polypill strategy. The PSA shows a 99.5% probability for the polypill strategy to be cost-effective and 46.8% chances to be costs saving.

Conclusion

Both risk equations result in comparable results on the cost-effectiveness of interventions for the secondary prevention of CV disease. The polypill strategy remains cost-effective compared to the common practice of using individual monocomponents concomitantly, reducing recurrent CV events at a moderately higher cost.

AMP-activated protein kinase (AMPK) signaling in GnRH neurons links energy status and reproduction

BACKGROUND

Reproduction is tightly coupled to body energy and metabolic status. GnRH neurons, master elements and final output pathway for the brain control of reproduction, directly or indirectly receive and integrate multiple metabolic cues to regulate reproductive function. Yet, the molecular underpinnings of such phenomenon remain largely unfolded. AMP-activated protein kinase (AMPK), the fundamental cellular sensor that becomes activated in conditions of energy deficit, has been recently shown to participate in the control of Kiss1 neurons, essential gatekeepers of the reproductive axis, by driving an inhibitory valence in situations of energy scarcity at puberty. However, the contribution of AMPK signaling specifically in GnRH neurons to the metabolic control of reproduction remains unknown.

METHODS

Double immunohistochemistry (IHC) was applied to evaluate expression of active (phosphorylated) AMPK in GnRH neurons and a novel mouse line, named GAMKO, with conditional ablation of the AMPK α1 subunit in GnRH neurons, was generated. GAMKO mice of both sexes were subjected to reproductive characterization, with attention to puberty and gonadotropic responses to kisspeptin and metabolic stress.

RESULTS

A vast majority (>95%) of GnRH neurons co-expressed pAMPK. Female (but not male) GAMKO mice displayed earlier puberty onset and exaggerated LH (as surrogate marker of GnRH) responses to kisspeptin-10 at the prepubertal age. In adulthood, GAMKO females retained increased LH responsiveness to kisspeptin and showed partial resilience to the inhibitory effects of conditions of negative energy balance on the gonadotropic axis. The modulatory role of AMPK in GnRH neurons required preserved ovarian function, since the differences in LH pulsatility detected between GAMKO and control mice subjected to fasting were abolished in ovariectomized animals.

CONCLUSIONS

Altogether, our data document a sex-biased, physiological role of AMPK signaling in GnRH neurons, as molecular conduit of the inhibitory actions of conditions of energy deficit on the female reproductive axis.

Metabolic programming of puberty: sexually dimorphic responses to early nutritional challenges

Body energy stores and metabolic cues influence the onset of puberty. However, the pubertal impact of early nutritional challenges has been only fragmentarily addressed. We evaluated here the consequences, in terms of pubertal timing and hormonal markers, of various nutritional manipulations during pre- or postnatal maturation in rats of both sexes. Males and females were submitted to gestational undernutrition (UNG) or peripubertal (SUB) subnutrition or were raised in large (LL; underfeeding) or small (SL; overfeeding) litters. In addition, groups of UNG, LL, and SL rats were fed on a high-fat diet (HFD) after weaning. Postnatal overfeeding resulted in higher body weights (BWs) during pubertal transition in both sexes, but only SL males displayed overtly advanced external signs of puberty. Postnatal underfeeding persistently decreased BW gain during puberty, yet the magnitude of pubertal delay was greater in LL males. In contrast, regardless of postnatal nutrition, HFD tended to advance the onset of puberty in females but did not alter pubertal timing in males. Likewise, SUB females displayed a marked delay in BW gain and puberty onset, whereas despite similar reduction in BW, SUB males showed normal timing of puberty. These sex divergences were also detected in various hormonal and metabolic indices so that postnatal overnutrition consistently increased LH, FSH, leptin, and insulin levels only in pubertal females, whereas HFD decreased gonadotropin levels in SL females but increased them in SL males. Notably, UNG rats did not show signs of delayed puberty but displayed a striking sex dimorphism in serum insulin/glucose levels, regardless of the diet, so that only UNG males had signs of presumable insulin resistance. Our data disclose important sex differences in the impact of various early nutritional challenges on the timing of puberty, which may help to explain the different trends of altered puberty and related comorbidities between sexes.

Cellular distribution, regulated expression, and functional role of the anorexigenic peptide, NUCB2/nesfatin-1, in the testis

Nesfatin-1, product of the precursor NEFA/nucleobindin2 (NUCB2), was initially identified as anorectic hypothalamic neuropeptide, acting in a leptin-independent manner. In addition to its central role in the control of energy homeostasis, evidence has mounted recently that nesfatin-1 is also produced in peripheral metabolic tissues, such as pancreas, adipose, and gut. Moreover, nesfatin-1 has been shown to participate in the control of body functions gated by whole-body energy homeostasis, including puberty onset. Yet, whether, as is the case for other metabolic neuropeptides, NUCB2/nesfatin-1 participates in the direct control of gonadal function remains unexplored. We document here for the first time the expression of NUCB2 mRNA in rat, mouse, and human testes, where NUCB2/nesfatin-1 protein was identified in interstitial mature Leydig cells. Yet in rats, NUCB2/nesfatin-1 became expressed in Sertoli cells upon Leydig cell elimination and was also detected in Leydig cell progenitors. Although NUCB2 mRNA levels did not overtly change in rat testis during pubertal maturation and after short-term fasting, NUCB2/nesfatin-1 content significantly increased along the puberty-to-adult transition and was markedly suppressed after fasting. In addition, testicular NUCB2/nesfatin-1 expression was up-regulated by pituitary LH, because hypophysectomy decreased, whereas human choriogonadotropin (super-agonist of LH receptors) replacement enhanced, NUCB2/nesfatin-1 mRNA and peptide levels. Finally, nesfatin-1 increased human choriogonadotropin-stimulated testosterone secretion by rat testicular explants ex vivo. Our data are the first to disclose the presence and functional role of NUCB2/nesfatin-1 in the testis, where its expression is regulated by developmental, metabolic, and hormonal cues as well as by Leydig cell-derived factors. Our observations expand the reproductive dimension of nesfatin-1, which may operate directly at the testicular level to link energy homeostasis, puberty onset, and gonadal function.

Role of the energy sensor adenosine monophosphate-activated protein kinase in the regulation of immature gonadotropin-releasing hormone neuron migration

BACKGROUND

The 5'-AMP-activated protein kinase (AMPK) plays a fundamental role in regulating energy homeostasis as well as feeding and metabolism, through central and peripheral actions. AMPK is activated by conditions causing ATP depletion and by different metabolic molecules, such as adiponectin and AMPK agonist, such as 5-aminoimidazole- 4-carboxamide-1-β-D-ribofuranoside (AICAR). AMPK activation has also been shown to affect the migration of different cell types and to participate in the central control of reproductive function, although information concerning AMPK and the development of the hypothalamic reproductive compartment is lacking.

AIM

To explore whether AMPK activation by globular adiponectin (gAdipo) and AICAR may affect the migratory ability of GnRH neurons.

MATERIALS AND METHODS

We used GN11 immature GnRH neurons (in vitro model system), RT-PCR and Western blot analysis, and Boyden's chamber assay.

RESULTS

gAdipo did not affect FBS-stimulated migration of GN11 cells and activated AMPK through the mandatory phosphorylation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) and Akt, which also interact one to each other. AICAR treatment inhibited FBS-stimulated GN11 cell migration, through a long-lasting activation of AMPK. A downstream activation of ERK1/2 by AICAR was also observed and inhibition of ERK1/2 amplified AICAR-induced inhibition of migration.

CONCLUSIONS

The direct, but not the indirect, activation of AMPK appears to negatively affect FBSinduced GN11 cell migration, suggesting that the final balance between pro-migratory and anti-migratory actions may also depend upon the specific sequence of intracellular signals activated by one agent.

Activation of microglia in specific hypothalamic nuclei and the cerebellum of adult rats exposed to neonatal overnutrition

Much attention has been drawn to the possible involvement of hypothalamic inflammation in the pathogenesis of metabolic disorders, especially in response to a high-fat diet. Microglia, the macrophages of the central nervous system, can be activated by proinflammatory signals resulting in the local production of specific interleukins and cytokines, which in turn could exacerbate the pathogenic process. Because obesity itself is considered to be a state of chronic inflammation, we evaluated whether being overweight results in microglial activation in the hypothalamus of rats on a normal diet. Accordingly, we used a model of neonatal overnutrition that entailed adjustment of litter size at birth (small litters: four pups/dam versus normal litters: 12 pups/dam) and resulted in a 15% increase in bodyweight and increased circulating leptin levels at postnatal day 60. Rats that were overnourished during neonatal life had an increased number of activated microglia in specific hypothalamic areas such as the ventromedial hypothalamus, which is an important site for metabolic control. However, this effect was not confined to the hypothalamus because significant microglial activation was also observed in the cerebellar white matter. There was no change in circulating tumour necrosis factor (TNF) α levels or TNFα mRNA levels in either the hypothalamus or cerebellum. Interleukin (IL)6 protein levels were higher in both the hypothalamus and cerebellum, with no change in IL6 mRNA levels. Because circulating IL6 levels were elevated, this rise in central IL6 could be a result of increased uptake. Thus, activation of microglia occurs in adult rats exposed to neonatal overnutrition and a moderate increase in weight gain on a normal diet, possibly representing a secondary response to systemic inflammation. Moreover, this activation could result in local changes in specific hypothalamic nuclei that in turn further deregulate metabolic homeostasis.

Acute inflammation reduces kisspeptin immunoreactivity at the arcuate nucleus and decreases responsiveness to kisspeptin independently of its anorectic effects

Severe inflammatory challenges are frequently coupled to decreased food intake and disruption of reproductive function, the latter via deregulation of different signaling pathways that impinge onto GnRH neurons. Recently, the hypothalamic Kiss1 system, a major gatekeeper of GnRH function, was suggested as potential target for transmitting immune-mediated repression of the gonadotropic axis during acute inflammation, and yet key facets of such a phenomenon remain ill defined. Using lipopolysaccharide S (LPS)-treated male rats as model of inflammation, we document herein the pattern of hypothalamic kisspeptin immunoreactivity (IR) and hormonal responses to kisspeptin during the acute inflammatory phase. LPS injections induced a dramatic but transient drop of serum LH and testosterone levels. Suppression of gonadotropic function was associated with a significant decrease in kisspeptin-IR in the arcuate nucleus (ARC) that was not observed under conditions of metabolic stress induced by 48-h fasting. In addition, absolute responses to kisspeptin-10 (Kp-10), in terms of LH and testosterone secretion, were significantly attenuated in LPS-treated males that also displayed a decrease in food intake and body weight. Yet pair-fed males did not show similar alterations in LH and testosterone secretory responses to Kp-10, whose magnitude was preserved, if not augmented, during food restriction. In summary, our data document the impact of acute inflammation on kisspeptin content at the ARC as key center for the neuroendocrine control of reproduction. Our results also suggest that suppressed gonadotropic function following inflammatory challenges might involve a reduction in absolute responsiveness to kisspeptin that is independent of the anorectic effects of inflammation.

The mammalian target of rapamycin as novel central regulator of puberty onset via modulation of hypothalamic Kiss1 system

The mammalian target of rapamycin (mTOR) is a serine/threonine kinase that operates as sensor of cellular energy status and effector for its coupling to cell growth and proliferation. At the hypothalamic arcuate nucleus, mTOR signaling has been recently proposed as transducer for leptin effects on energy homeostasis and food intake. However, whether central mTOR also participates in metabolic regulation of fertility remains unexplored. We provide herein evidence for the involvement of mTOR in the control of puberty onset and LH secretion, likely via modulation of hypothalamic expression of Kiss1. Acute activation of mTOR by l-leucine stimulated LH secretion in pubertal female rats, whereas chronic l-leucine infusion partially rescued the state of hypogonadotropism induced by food restriction. Conversely, blockade of central mTOR signaling by rapamycin caused inhibition of the gonadotropic axis at puberty, with significantly delayed vaginal opening, decreased LH and estradiol levels, and ovarian and uterine atrophy. Inactivation of mTOR also blunted the positive effects of leptin on puberty onset in food-restricted females. Yet the GnRH/LH system retained their ability to respond to ovariectomy and kisspeptin-10 after sustained blockade of mTOR, ruling out the possibility of unspecific disruption of GnRH function by rapamycin. Finally, mTOR inactivation evoked a significant decrease of Kiss1 expression at the hypothalamus, with dramatic suppression of Kiss1 mRNA levels at the arcuate nucleus. Altogether our results unveil the role of central mTOR signaling in the control of puberty onset and gonadotropin secretion, a phenomenon that involves the regulation of Kiss1 and may contribute to the functional coupling between energy balance and gonadal activation and function.

Delayed puberty in spontaneously hypertensive rats involves a primary ovarian failure independent of the hypothalamic KiSS-1/GPR54/GnRH system

Spontaneously hypertensive (SH) rats, extensively used as experimental models of essential human hypertension, display important alterations in the neuroendocrine reproductive axis, which manifest as markedly delayed puberty onset in females but whose basis remains largely unknown. We analyze herein in female SH rats: 1) possible alterations in the expression and function of KiSS-1/GPR54 and GnRH/GnRH-receptor systems, 2) the integrity of feedback mechanisms governing the hypothalamic-pituitary-ovarian axis, and 3) the control of ovarian function by gonadotropins. Our data demonstrate that, despite overtly delayed puberty, no significant decrease in hypothalamic KiSS-1, GPR54, or GnRH mRNA levels was detected in this strain. Likewise, in vivo gonadotropin responses to ovariectomy and systemic kisspeptin-10 or GnRH administration, as well as in vitro gonadotropin responses to GnRH, were fully preserved in SH rats. Moreover, circulating LH levels were grossly conserved during prepubertal maturation, whereas FSH levels were even enhanced from d 20 postpartum onwards. In striking contrast, ovarian weight and hormone (progesterone and testosterone) responses to human chorionic gonadotropin (CG) in vitro were profoundly decreased in SH rats, with impaired follicular development and delayed ovulation at puberty. Such reduced hormonal responses to human CG could not be attributed to changes in LH/CG or FSH-receptor mRNA expression but might be linked to blunted P450scc, 3beta-hydroxy steroid dehydrogenase, and aromatase mRNA levels in ovaries from SH rats. In conclusion, our results indicate that the expression and function of KiSS-1/GPR54 and GnRH/GnRH-receptor systems is normal in SH rats, whereas ovarian development, steroidogenesis, and responsiveness to gonadotropins are strongly compromised.

Persistent impairment of hypothalamic KiSS-1 system after exposures to estrogenic compounds at critical periods of brain sex differentiation

Attainment of reproductive capacity at puberty relies on a complex series of maturational events that include sexual differentiation of the brain; a hormonally driven phenomenon that takes place at early stages of development (critical period). Alterations of sex steroid milieu during such critical period disrupt pubertal maturation and gonadotropic function later in life, through mechanisms that remain partially unknown. Kisspeptins, products of the KiSS-1 gene acting via G protein-coupled receptor 54, have recently emerged as essential gatekeepers of puberty onset and reproductive function. By using rat models of neonatal administration of estrogenic compounds, we provide herein compelling evidence for the functional impairment of the hypothalamic KiSS-1 system at the time preceding puberty after early inappropriate exposures during brain sex differentiation. Neonatal injection of estradiol benzoate to male and female rats resulted in a dose-dependent decrease in hypothalamic KiSS-1 mRNA levels at the prepubertal stage, linked to lowering of serum LH concentrations. Yet, despite persistently decreased basal gonadotropin levels in estrogenized animals, intracerebral injection of kisspeptin evoked potent LH and FSH secretory responses, similar in magnitude to those of control animals. Estrogenized rats also showed defective levels of hypothalamic KiSS-1 mRNA and circulating gonadotropins in response to gonadectomy, whereas exogenous kisspeptin was capable to enhance further LH and FSH secretion in this model. Finally, protocols of neonatal exposure to high doses of an environmentally relevant estrogen, bisphenol-A, mimicked the effects of estradiol benzoate in terms of hypothalamic expression of KiSS-1 gene at the prepubertal period. Altogether, our data document the sensitivity of the hypothalamic KiSS-1 system to alterations in sex steroid milieu during critical periods of brain sex differentiation, and suggest that lowering of endogenous kisspeptin tone induced by early exposures to xeno-estrogens might be mechanistically relevant for disruption of gonadotropin secretion and puberty onset later in life.

KiSS-1 in the mammalian ovary: distribution of kisspeptin in human and marmoset and alterations in KiSS-1 mRNA levels in a rat model of ovulatory dysfunction

Kisspeptins, the products of the KiSS-1 gene acting via G protein-coupled receptor 54 (GPR54), have recently emerged as pivotal signals in the hypothalamic network triggering the preovulatory surge of gonadotropins and, hence, ovulation. Additional actions of kisspeptins at other levels of the hypothalamic-pituitary-ovarian axis have been suggested but remain to date scarcely studied. We report herein the pattern of expression of KiSS-1 and GPR54 in the human and nonhuman primate ovary and evaluate changes in ovarian KiSS-1 expression in a rat model of ovulatory dysfunction. KiSS-1 and GPR54 mRNAs were detected in human ovarian tissue and cultured granulosa-lutein cells. In good agreement, kisspeptin immunoreactivity was observed in cyclic human and marmoset ovaries, with prominent signals in the theca layer of growing follicles, corpora lutea, interstitial gland, and ovarian surface epithelium. GPR54 immunoreactivity was also found in human theca and luteal cells. Administration of indomethacin to cyclic female rats disturbed ovulation and resulted in a dramatic drop in ovarian KiSS-1, but not GPR54, cyclooxygenase-2 (COX-2), or progesterone receptor, mRNA levels at the time of ovulation; an effect mimicked by the selective COX-2 inhibitor NS398 and rescued by coadministration of PGE(2). Likewise, the stimulatory effect of human choriogonadotropin on ovarian KiSS-1 expression was partially blunted by indomethacin. In contrast, KiSS-1 mRNA levels remained unaltered in another model of ovulatory failure, i.e., the RU486-treated rat. In summary, we document for the first time the expression of KiSS-1/kisspeptin and GPR54 in the human and nonhuman primate ovary. In addition, we provide evidence for the ability of inhibitors of COX-2, known to disturb follicular rupture and ovulation, to selectively alter the expression of KiSS-1 gene in rat ovary. Altogether, our results are suggestive of a conserved role of local KiSS-1 in the direct control of ovarian functions in mammals.

Alterations in hypothalamic KiSS-1 system in experimental diabetes: early changes and functional consequences

Using long-term streptozotocin (STZ)-treated male rats, we recently proposed that defective function of hypothalamic KiSS-1 system is mechanistically relevant for central hypogonadotropism of uncontrolled diabetes. However, the temporal pattern of such defects and its potential contribution to disturbed gonadotropin secretion in the diabetic female remain so far unexplored. To cover these issues, expression analyses and hormonal tests were conducted in diabetic male (1 wk after STZ; short term) and female (4 wk after STZ; long term) rats. Short-term diabetic males had lower basal testosterone levels and decreased gonadotropin responses to orchidectomy (ORX), which associated with significantly attenuated post-ORX rises of hypothalamic KiSS-1 mRNA. Yet kisspeptin administration to diabetic males was able to acutely elicit supramaximal LH and testosterone responses and normalize post-ORX gonadotropin secretion. Long-term diabetic females showed persistent anestrus and significantly decreased basal gonadotropin levels as well as blunted LH responses to ovariectomy; changes that were linked to lowering of basal and postovariectomy expression of hypothalamic KiSS-1 mRNA. Moreover, despite prevailing gonadotropin suppression, LH responses to acute kisspeptin administration were fully preserved, and even enhanced after its repeated injection, in diabetic females. In sum, our present findings further define the temporal course and mechanistic relevance of altered hypothalamic KiSS-1 system in the hypogonadotropic state of uncontrolled diabetes. Furthermore, our data provide the basis for the potential therapeutic intervention of the KiSS-1 system as adjuvant in the management of disturbed gonadotropin secretion of type 1 diabetes in the female.

Kisspeptins and the control of gonadotropin secretion in male and female rodents

Kisspeptins, the products of KiSS-1 gene acting via G protein-coupled receptor 54 (GPR54), have recently emerged as fundamental gatekeepers of gonadal function by virtue of their ability to stimulate gonadotropin secretion. Indeed, since the original disclosure of the reproductive facet of the KiSS-1/GPR54 system, an ever-growing number of studies have substantiated the extraordinary potency of kisspeptins to elicit gonadotropin secretion in different mammalian species, under different physiologic and experimental conditions, and through different routes of administration. In this context, studies conducted in laboratory rodents have been enormously instrumental to characterize: (i) the primary mechanisms of action of kisspeptins in the control of gonadotropin secretion; (ii) the pharmacological consequences of acute vs. continuous activation of GPR54; (iii) the roles of specific populations of kisspeptin-producing neurons at the hypothalamus in mediating the feedback effects of sex steroids; (v) the function of kisspeptins in the generation of the pre-ovulatory surge of gonadotropins; and (iv) the influence of sex steroids on GnRH/gonadotropin responsiveness to kisspeptins. While some of those aspects of kisspeptin function will be covered elsewhere in this Special Issue, we summarize herein the most salient data, obtained in laboratory rodents, that have helped to define the physiologic roles and putative pharmacological implications of kisspeptins in the control of male and female gonadotropic axis.

KiSS-1/kisspeptins and the metabolic control of reproduction: physiologic roles and putative physiopathological implications

It is well established that reproductive function is gated by the state of energy reserves of the organism; conditions of metabolic stress and energy insufficiency being frequently coupled to disturbed reproductive maturation and/or infertility. In addition, obesity is also commonly linked to altered puberty onset and reproductive impairment. Such an impact of energy status on the reproductive axis is conveyed through a number of neuropeptide hormones and metabolic cues, whose nature and mechanisms of action have begun to be deciphered only in recent years. In this context, the emergence of kisspeptins, encoded by the KiSS-1 gene, and their receptor, GPR54, as indispensable signals for normal pubertal maturation and gonadal function, has raised the possibility that the KiSS-1/GRP54 system might also participate in coupling body energy status and reproduction. We revise herein the experimental evidence, gathered in rodent models, supporting the contention that the hypothalamic KiSS-1 system operates as a central conduit for conveying metabolic information onto the centers governing reproductive function, through a putative leptin-kisspeptin-GnRH pathway. Admittedly, key aspects of this 'metabolic' network involving the KiSS-1 system, such as its different peripheral regulators and central effectors, have not been fully elucidated. Nonetheless, the proposed hypothalamic circuitry, responsible for transmitting metabolic information onto the reproductive axis through KiSS-1 neurons, might explain, at least in part, the mechanisms for the well-known alterations of fertility linked to conditions of disturbed energy balance in humans, from anorexia nervosa to morbid obesity.

Follicle-stimulating hormone responses to kisspeptin in the female rat at the preovulatory period: modulation by estrogen and progesterone receptors

Ovulation is triggered by the preovulatory surge of gonadotropins that, in rodents, is defined by the concomitant rise in circulating LH and FSH at the afternoon of proestrus (primary surge), followed by persistently elevated FSH levels at early estrus (secondary surge). In recent years, kisspeptins, products of the KiSS-1 gene that act via G protein-coupled receptor 54, have emerged as an essential hypothalamic conduit for the generation of the preovulatory LH surge by conveying positive feedback effects of estradiol onto GnRH neurons, an event that involves not only estradiol-induced transcription of the KiSS-1 gene at the anteroventral periventricular nucleus but also its ability to modulate GnRH/LH responses to kisspeptin. However, little is known about the potential modulation of FSH responsiveness to kisspeptin by sex steroids in the cyclic female. We report herein analyses on the consequences of selective blockade of estrogen receptors (ER)-alpha and -beta, as well as progesterone receptor (PR), on the ovulatory surges of FSH and their modulation by kisspeptin. Antagonism of ERalpha or PR equally blunted the primary and secondary surges of FSH and nullified FSH responses to kisspeptin at the preovulatory period. Conversely, selective blockade of ERbeta failed to induce major changes in terms of endogenous FSH surges, yet it decreased FSH responses to exogenous kisspeptin. In contrast, FSH responses to GnRH were fully conserved after ERbeta blockade and partially preserved after inhibition of ERalpha and PR signaling. Finally, secondary FSH secretion was rescued by kisspeptin in females with selective blockade of ERalpha but not PR. In sum, our results substantiate a concurrent, indispensable role of ERalpha and PR in the generation of FSH surges and the stimulation of FSH responses to kisspeptin at the ovulatory period. In addition, our data suggest that ERbeta might operate as a subtle, positive modulator of the preovulatory FSH responses to kisspeptin, a role that is opposite to its putative inhibitory action on kisspeptin-induced LH secretion and might contribute to the dissociation of gonadotropin secretion at the ovulatory phase in the cyclic female rat.

Desensitization of gonadotropin responses to kisspeptin in the female rat: analyses of LH and FSH secretion at different developmental and metabolic states

Kisspeptins have emerged as potent elicitors of gonadotropin secretion and, therefore, putative targets for pharmacological intervention. In this context, desensitization of gonadotropin responses to continuous administration of kisspeptins has begun to be characterized, but information so far available is mostly restricted to LH responses in males, whereas the similar phenomenon in females, of obvious therapeutic interest, remains virtually unexplored. We report herein LH and FSH responses to continuous intracerebral administration of kisspeptin in female rats at different developmental and metabolic states. Infusion of kisspeptin-10 to adult female rats induced a transient elevation in serum LH concentrations, followed by a precipitous drop and normalization of LH levels thereafter. Elevation of LH after kisspeptin infusion was prolonged in underfed animals; a phenomenon mimicked by leptin administration. Conversely, FSH levels were persistently heightened along continuous kisspeptin infusion, but duration of this response was shortened by undernutrition. In pubertal females, LH and FSH levels remained elevated at the end of a 7-day infusion of kisspeptin; responses whose magnitude was augmented by subnutrition but not mimicked by leptin. In all settings, terminal gonadotropin-releasing hormone responses were fully preserved, suggesting that eventual desensitization must occur upstream from the pituitary. In summary, our current data document the pharmacological consequences of continuous administration of kisspeptin to female rats, with remarkable differences being detected between LH and FSH responses, in different developmental and metabolic states. These observations of potential pharmacological interest might help also to delineate the physiological roles of kisspeptins in the dynamic regulation of gonadotropin secretion in the female.

Opposite roles of estrogen receptor (ER)-alpha and ERbeta in the modulation of luteinizing hormone responses to kisspeptin in the female rat: implications for the generation of the preovulatory surge

Ovulation is triggered by the preovulatory rise of gonadotropins, which is in turn elicited by the preceding increase in circulating estrogen. Kisspeptins, ligands of G protein-coupled receptor 54 encoded by the KiSS-1 gene, have emerged as potent stimulators of GnRH/LH secretion, and KiSS-1 neurons at the anteroventral periventricular nucleus have been shown to be involved in the generation of preovulatory LH surge, estrogen being a potent elicitor of KiSS-1 gene expression selectively at the anteroventral periventricular nucleus. Whether, in addition to transcriptional effects, estrogen influences other aspects of kisspeptin-induced GnRH/LH release in the female remains unexplored. We provide herein evidence for the specific roles of estrogen receptor (ER)-alpha and ERbeta in the modulation of LH responses to kisspeptin and the generation of the preovulatory surge. Selective blockade of ERalpha in cyclic females blunted LH responses to kisspeptin, eliminated the endogenous preovulatory rise of LH, and blocked ovulation. In contrast, antagonism of ERbeta failed to cause major changes in terms of LH surge and ovulatory rate but significantly augmented acute LH responses to kisspeptin. Notably, defective LH secretion and ovulation after ERalpha blockade were not observed after GnRH stimulation, which elicited maximal acute (<2 h) LH responses regardless of ERalpha/ERbeta signaling. In addition, net LH secretion in response to kisspeptin was decreased by ovariectomy and increased after selective activation of ERalpha but not ERbeta. Altogether, our data document the prominent positive role of ERalpha in the regulation of GnRH/LH responsiveness to kisspeptin and, thereby, ovulation. In addition, our results disclose the putative function of ERbeta as negative modifier of GnRH/LH response to kisspeptin, a phenomenon that might contribute to partially restraining LH secretion at certain physiological states.

Selective role of neuropeptide Y receptor subtype Y2 in the control of gonadotropin secretion in the rat

Different signals with key roles in energy homeostasis regulate the reproductive axis. These include neuropeptide Y and polypeptide YY(3-36), whose type Y(2) receptor is the most abundant of this family in the brain. We evaluated herein the putative roles of Y(2) receptors in the control of gonadotropin secretion by means of central administration of PYY(13-36) (agonist of Y(2) receptors) and BIIE 0246 (antagonist of Y(2) receptors) to intact and orchidectomized male rats. In addition, the ability of PYY(13-36) to elicit GnRH and gonadotropin secretion in vitro and the impact of fasting on LH responses to PYY(13-36) in vivo were also monitored. Central administration of PYY(13-36) significantly decreased the circulating levels of both gonadotropins, an effect that was observed in prepubertal and adult rats. Yet a dual action of Y(2) receptors in the control of male gonadotropic axis was evidenced as their activation induced 1) stimulation of gonadotropin responses to GnRH at the pituitary but 2) inhibition of GnRH secretion at the hypothalamus. Antagonization of Y(2) receptors failed to modify basal LH secretion in intact males either after being fed ad libitum or after being fasted. In contrast, their central blockade in orchidectomized rats evoked a significant increase in circulating LH and FSH level, suggesting the constitutive activation of Y(2) receptor in such stimulated conditions. In summary, our data evidence a complex mode of action of Y(2) receptors in the control of gonadotropic axis, with stimulatory and inhibitory actions at different levels of the system that are sensitive to the gonadal status.

Neuromedin s as novel putative regulator of luteinizing hormone secretion

Neuromedin S (NMS), a 36 amino acid peptide structurally related to neuromedin U, was recently identified in rat brain as ligand for the G protein-coupled receptor FM4/TGR-1, also termed neuromedin U receptor type-2 (NMU2R). Central expression of NMS appears restricted to the suprachiasmatic nucleus, and NMS has been involved in the regulation of dark-light rhythms and suppression of food intake. Reproduction is known to be tightly regulated by metabolic and photoperiodic cues. Yet the potential contribution of NMS to the control of reproductive axis remains unexplored. We report herein analyses of hypothalamic expression of NMS and NMU2R genes, as well as LH responses to NMS, in different developmental and functional states of the female rat. Expression of NMS and NMU2R genes was detected at the hypothalamus along postnatal development, with significant fluctuations of their relative levels (maximum at prepubertal stage and adulthood). In adult females, hypothalamic expression of NMS (which was confined to suprachiasmatic nucleus) and NMU2R significantly varied during the estrous cycle (maximum at proestrus) and was lowered after ovariectomy and enhanced after progesterone supplementation. Central administration of NMS evoked modest LH secretory responses in pubertal and cyclic females at diestrus, whereas exaggerated LH secretory bursts were elicited by NMS at estrus and after short-term fasting. Conversely, NMS significantly decreased elevated LH concentrations of ovariectomized rats. In summary, we provide herein novel evidence for the ability of NMS to modulate LH secretion in the female rat. Moreover, hypothalamic expression of NMS and NMU2R genes appeared dependent on the functional state of the female reproductive axis. Our data are the first to disclose the potential implication of NMS in the regulation of gonadotropic axis, a function that may contribute to the integration of circadian rhythms, energy balance, and reproduction.

Effects of galanin-like peptide on luteinizing hormone secretion in the rat: sexually dimorphic responses and enhanced sensitivity at male puberty

Reproductive function is exquisitely sensitive to adequacy of nutrition and fuel reserves, through mechanisms that are yet to be completely elucidated. Galanin-like peptide (GALP) has recently emerged as another neuropeptide link that couples reproduction and metabolism. However, although the effects of GALP on luteinizing hormone (LH) secretion have been studied, no systematic investigation on how these responses might differ along sexual maturation and between sexes has been reported. Moreover, the influence of metabolic status and potential interplay with other relevant neurotransmitters controlling LH secretion remain ill defined. These facets of GALP physiology were addressed herein. Intracerebral injection of GALP to male rats induced a dose-dependent increase in serum LH levels, the magnitude of which was significantly greater in pubertal than in adult males. In contrast, negligible LH responses to GALP were detected in pubertal or adult female rats at diestrus. Neonatal androgen treatment to females failed to "masculinize" the pattern of LH response to GALP. In addition, metabolic stress by short-term fasting did not prevent but rather amplified LH responses to GALP in pubertal males, whereas these responses were abrogated by pharmacological inhibition of nitric oxide synthesis. We conclude that the ability of GALP to evoke LH secretion is sexually differentiated, with maximal responses at male puberty, a phenomenon which was not reverted by manipulation of sex steroid milieu during the critical neonatal period and was sensitive to metabolic stress. This state of LH hyperresponsiveness may prove relevant for the mechanisms relaying metabolic status to the reproductive axis in male puberty.

Expression of KiSS-1 in rat ovary: putative local regulator of ovulation?

Kisspeptins, the products of KiSS-1 gene, and their receptor, GPR54, have recently emerged as essential gatekeepers of reproduction, mainly through regulation of GnRH secretion at the hypothalamus. However, the profound hypogonadotropism linked to GPR54 inactivation is likely to mask additional functions of this system at other levels of the gonadal axis, in which expression of KiSS-1 and GPR54 has been preliminarily reported. We describe herein the expression of KiSS-1 gene and kisspeptin immunoreactivity (IR) in rat ovary and evaluate its developmental and hormonal regulation. KiSS-1 and GPR54 mRNAs were persistently detected in adult ovary along estrous cycle. Yet, contrary to GPR54, ovarian KiSS-1 levels fluctuated in a cyclic-dependent manner, with a robust increase in the afternoon of proestrus, i.e. preceding ovulation. In addition, kisspeptin-IR was observed in rat ovary, with strong signals in theca layers of growing follicles, corpora lutea, and interstitial gland, compartments in which modest GPR54-IR was also detected. Interestingly, the rise in ovarian KiSS-1 mRNA at proestrus was prevented by blockade of preovulatory gonadotropin surge and restored by replacement with human chorionic gonadotropin as superagonist of LH. In addition, immature ovaries showed low to negligible levels of KiSS-1 mRNA, which were significantly enhanced by gonadotropin priming. In summary, we present novel evidence for the developmental and hormonally regulated expression of the KiSS-1 gene, and the presence of kisspeptin-IR, in rat ovary. The ability of the LH surge to timely induce ovarian expression of KiSS-1 at the preovulatory period strongly suggests a previously unsuspected role of locally produced kisspeptin in the control of ovulation.

Ontogeny and mechanisms of action for the stimulatory effect of kisspeptin on gonadotropin-releasing hormone system of the rat

Kisspeptins have recently emerged as essential regulators of gonadotropin secretion and puberty onset. These functions are primarily conducted by stimulation of hypothalamic gonadotropin-releasing hormone (GnRH) secretion. However, relevant aspects of KiSS-1 physiology, including the ontogeny and major signaling systems of its stimulatory action, remain to be fully elucidated. To cover these issues, the effects of kisspeptin-10 on GnRH and LH secretion were monitored at early stages of postnatal maturation, and potential changes in the sensitivity to kisspeptin were assessed along the pubertal transition in the rat. In addition, the signaling cascades involved in kisspeptin-induced GnRH secretion were explored by means of pharmacological blockade using rat hypothalamic explants. Despite sexual immaturity, kisspeptin-10 potently elicited GnRH release ex vivo and LH secretion in vivo at early stages (neonatal to juvenile) of postnatal development. Yet, LH responsiveness to low doses of kisspeptin was enhanced in peri-pubertal animals. Concerning GnRH secretion, the stimulatory action of kisspeptin-10 required activation of phospholipase-C, mobilization of intracellular Ca2+ and recruitment of ERK1/2 and p38 kinases, but was preserved after blockade of type 2 cyclo-oxygenase and prostaglandin synthesis. In summary, our present data document the ontogeny, sensitivity and intracellular signals for the stimulatory action of kisspeptin on the GnRH/LH axis in the rat. Although LH responses to low doses of kisspeptin appeared to be enhanced at puberty, kisspeptin was able to readily activate the GnRH system at early stages of postnatal maturation. These observations further stress the essential role of kisspeptin in normal, and eventually pathological, timing of puberty.

Novel signals for the integration of energy balance and reproduction

Although the close link between body weight and fertility has been known for eons, only recently have the peripheral signals and neuroendocrine networks responsible for such a phenomenon begun to be identified. A key event in this field was the cloning of the adipocyte-derived hormone leptin, which has been demonstrated as a pivotal regulator for the integration of energy homeostasis and reproduction. In addition, other metabolic hormones, such as insulin, contribute to this physiological integration. Moreover, compelling experimental evidence implicates hormonal products of the gastrointestinal tract as adjuncts in the complex coordination and regulation of body weight and reproduction. Here, we review recent studies evaluating the reproductive effects and sites of action of ghrelin and PYY3-36, two hormonal signals of gastrointestinal origin involved in the control food intake and energy balance. In addition, we summarize the potential contribution of kisspeptin, the recently characterized gatekeeper of the GnRH system encoded by Kiss1 gene, to integrating reproductive function and energy status. Evidence suggests that besides having direct gonadal effects, ghrelin may participate in the regulation of gonadotropin secretion and it may influence the timing of puberty. Likewise, PYY3-36 modulates GnRH and gonadotropin release. In addition, the hypothalamic KiSS-1 system is sensitive to nutritional status, and its diminished expression during states of negative energy balance might contribute to the suppression of reproductive function in such conditions. We propose that the peripheral hormones, ghrelin and PYY3-36, and the central neuropeptide, kisspeptin, are 'novel' players in the neuroendocrine networks that integrate energy balance and reproduction.

Stimulatory effect of PYY-(3-36) on gonadotropin secretion is potentiated in fasted rats

Development and normal function of the reproductive axis requires a precise degree of body energy stores. Polypeptide YY-(3-36) [PYY-(3-36)] is a gastrointestinal secreted molecule recently shown to be involved in the control of food intake with agonistic activity on neuropeptide Y (NPY) receptor subtypes Y2 and Y5. Notably, PYY-(3-36) has been recently demonstrated as putative regulator of gonadotropin secretion in the rat. However, the "reproductive" facet of this factor remains to be fully elucidated. In this context, we report herein our analyses of the influence of the nutritional status on the effects of PYY-(3-36) upon GnRH and gonadotropin secretion. The major findings of our study are 1) the stimulatory effect of central administration of PYY-(3-36) on LH secretion was significantly enhanced after fasting and blocked by a GnRH antagonist; 2) besides central effects, PYY-(3-36) elicited LH and FSH secretion directly at the pituitary level, a response that is also augmented by fasting; 3) PYY-(3-36) inhibited GnRH secretion by hypothalamic fragments from male rats fed ad libitum, whereas a significant stimulatory effect was observed after fasting; and 4) the increase in the gonadotropin responsiveness to PYY-(3-36) in fasting was not associated with changes in the expression of Y2 and Y5 receptor genes at hypothalamus and/or pituitary. In conclusion, our study extends our previous observations suggesting a relevant, mostly stimulatory, role of PYY-(3-36) in the control of gonadotropin secretion. Strikingly, such an effect was significantly enhanced by fasting. Considering the proposed decrease in PYY-(3-36) levels after fasting, the possibility that reduced PYY-(3-36) secretion might contribute to defective function of the gonadotropic axis after food deprivation merits further investigation.

Effects of single or repeated intravenous administration of kisspeptin upon dynamic LH secretion in conscious male rats

The ability of kisspeptins, ligands of the G protein-coupled receptor 54, to potently elicit LH secretion is now undisputed. Yet, most of the pharmacological characterization of their gonadotropin-releasing effects has been conducted after intracerebral administration. In contrast, the effects of peripheral injection of kisspeptin remains less well defined. In this study, dynamic LH secretory responses to iv administration of kisspeptin-10 in different experimental settings are presented, and compared with those evoked by kisspeptin-52, using a protocol of serial blood sampling in conscious, freely moving male rats. LH responsiveness to peripheral administration of kisspeptin appeared extremely sensitive, as doses as low as 0.3 nmol/kg (0.1 microg/rat) evoked robust LH bursts, the magnitude of which was dose-dependent and apparently maximal in response to 3.0 and 30 nmol/kg kisspeptin-10. The ability of kisspeptin-10 to stimulate LH release was fully preserved, and even doubled in terms of relative increases, after short-term fasting despite suppression of prevailing LH levels. Repeated injections of kisspeptin-10 (four boluses, at 75-min intervals) evoked associated LH secretory pulses, the magnitude of which remained constant along the study period. Moreover, in this setting, in vivo LH responses to a terminal injection of GnRH were preserved, whereas basal and depolarization-induced GnRH release ex vivo was significantly enhanced. Finally, iv administration of kisspeptin-52 elicited dynamic LH responses analogous to that of kisspeptin-10; yet, their net magnitude and duration was slightly greater. In summary, we present in this study a series of experiments on the effects of systemic (iv) injection of single or repeated doses of kisspeptin upon dynamic LH secretion in conscious male rats. Aside from potential physiologic relevance, our present data might contribute to setting the basis for the rational therapeutic use of kisspeptin analogs in the pharmacological manipulation of the gonadotropic axis.

Hypothalamic expression of KiSS-1 system and gonadotropin-releasing effects of kisspeptin in different reproductive states of the female Rat

Kisspeptins, products of the KiSS-1 gene with ability to bind G protein-coupled receptor 54 (GPR54), have been recently identified as major gatekeepers of reproductive function with ability to potently activate the GnRH/LH axis. Yet, despite the diversity of functional states of the female gonadotropic axis, pharmacological characterization of this effect has been mostly conducted in pubertal animals or adult male rodents, whereas similar studies have not been thoroughly conducted in the adult female. In this work, we evaluated maximal LH and FSH secretory responses to kisspeptin-10, as well as changes in sensitivity and hypothalamic expression of KiSS-1 and GPR54 genes, in different physiological and experimental models in the adult female rat. Kisspeptin-10 (1 nmol, intracerebroventricular) was able to elicit robust LH bursts at all phases of the estrous cycle, with maximal responses at estrus; yet, in diestrus LH, responses to kisspeptin were detected at doses as low as 0.1 pmol. In contrast, high doses of kisspeptin only stimulated FSH secretion at diestrus. Removal of ovarian sex steroids did not blunt the ability of kisspeptin to further elicit stimulated LH and FSH secretion, but restoration of maximal responses required replacement with estradiol and progesterone. Finally, despite suppressed basal levels, LH and FSH secretory responses to kisspeptin were preserved in pregnant and lactating females, although the magnitude of LH bursts and the sensitivity to kisspeptin were much higher in pregnant dams. Interestingly, hypothalamic KiSS-1 gene expression significantly increased during pregnancy, whereas GPR54 mRNA levels remained unaltered. In summary, our current data document for the first time the changes in hypothalamic expression of KiSS-1 system and the gonadotropic effects (maximal responses and sensitivity) of kisspeptin in different functional states of the female reproductive axis. The present data may pose interesting implications in light of the potential therapeutic use of kisspeptin analogs in the pharmacological manipulation of the gonadotropic axis in the female.

Translocation of AIF in the human and rat striatum following protracted haloperidol, but not clozapine treatment

Loss of mitochondrial membrane integrity and consequent release of apoptogenic factors may be involved in mediating striatal neurodegeneration after prolonged treatment with the typical antipsychotic drug haloperidol. Apoptosis-inducing factor (AIF), an intramitochondrial protein, may have a large influence on mediating haloperidol-induced striatal neuron destruction. Translocation of this protein from mitochondria to the nucleus promotes cell death independently of the caspase cascade. To examine how AIF may contribute to haloperidol-induced apoptosis, AIF translocation was observed in three haloperidol treatment paradigms. SH-SY5Y cells were treated with both haloperidol and clozapine and examined for AIF immunofluorescence. Immunohistochemistry was also performed on human striatal sections obtained from the Stanley Foundation Neuropathology Consortium and on rat brain sections following 28 days of antipsychotic drug treatment. In the cellular model haloperidol, but not clozapine treatment increased the nuclear AIF immunofluorescent signal and decreased cell viability. Corollary to these findings, striatal sections from patients who had taken haloperidol and rats who were administered haloperidol both had an elevated nuclear AIF signal. The results provide novel evidence implicating the involvement of AIF in haloperidol-associated apoptosis and its relevance to the development of typical antipsychotic drug-related adverse effects such as tardive dyskinesia.

cDNA array reveals increased expression of glucose-dependent insulinotropic polypeptide following chronic clozapine treatment: role in atypical antipsychotic drug-induced adverse metabolic effects

Clozapine is an atypical antipsychotic drug with unique pharmacological and therapeutic properties. Unlike the typical antipsychotic drug, haloperidol, clozapine does not cause extrapyramidal side effects; however, weight gain, dyslipidemia, and type II diabetes are commonly associated with the use of this drug in subjects with schizophrenia. The aim of this study was to profile gene expression in the rat striatum following clozapine treatment. Chronic treatment with clozapine revealed upregulation of several genes including the glucose-dependent insulinotropic polypeptide (GIP) gene by over 200% in the rat striatum. The cDNA array results for the GIP gene were confirmed by real-time RT-PCR as well as by radioimmunoassay. Expression of the GIP gene in the central nervous system is consistent with the results of retinal GIP gene expression as reported by other investigators. Taken together, these findings implicate the possible role of GIP as a neuromodulator in the central nervous system. GIP is an insulinotropic agent with stimulatory effects on insulin synthesis and release from the pancreas. However, changes in brain GIP levels are most likely unrelated to the metabolic adverse effects (dyslipidemia, type II diabetes, weight gain) associated with clozapine treatment. Therefore, we also measured GIP gene expression in the K-cell-rich regions, duodenum and jejunum (small intestine), and plasma GIP levels using radioimmunoassay following chronic treatment with clozapine. GIP mRNA levels in the small intestine and the plasma GIP at the protein level were significantly elevated in clozapine-treated subjects. Furthermore, as observed in humans, chronic clozapine treatment also caused weight gain, and increased levels of insulin, triglycerides and leptin in the plasma. These results suggest that adverse metabolic effects associated with clozapine treatment may be related to its ability to increase intestinal gene expression for GIP.

Pattern of orexin expression and direct biological actions of orexin-a in rat testis

Orexins, hypothalamic neuropeptides initially involved in the control of food intake and sleep-wake cycle, have recently emerged as pleiotropic regulators of different biological systems, including the reproductive axis. Besides central actions, peripheral expression and functions of orexins have been reported, and prepro-orexin and orexin type-1 receptor mRNAs have been detected in the testis. However, the pattern of expression and biological actions of orexin in the male gonad remain mostly unexplored. In this study, we report analyses on testicular prepro-orexin mRNA expression and orexin-A immunoreactivity in different experimental settings, and on direct effects of orexin-A on seminiferous tubule functions. Expression of prepro-orexin mRNA was demonstrated in the rat testis at different stages of postnatal development, with negligible levels at early juvenile period and maximum values in adulthood. Likewise, orexin-A immunoreactivity was demonstrated along postnatal maturation, with strong peptide signal in Leydig cells and spermatocytes at specific stages of meiosis. Testicular expression of prepro-orexin mRNA appeared hormonally regulated; its levels decreased after hypophysectomy and increased after gonadotropin replacement and ghrelin stimulation. Finally, orexin-A suppressed the expression of key Sertoli cell genes, such as Müllerian-inhibiting substance and stem cell factor, and inhibited DNA synthesis in specific stages of the seminiferous epithelium. In conclusion, we provide evidence for the regulated expression of orexin in the rat testis and its potential involvement in the control of seminiferous tubule functions. Together with our recent results on the expression of orexin type-1 receptor in the rat testis, our data further document a novel testicular site of action of orexins in the control of male reproductive axis.

Changes in hypothalamic KiSS-1 system and restoration of pubertal activation of the reproductive axis by kisspeptin in undernutrition

Activation of the gonadotropic axis critically depends on sufficient body energy stores, and conditions of negative energy balance result in lack of puberty onset and reproductive failure. Recently, KiSS-1 gene-derived kisspeptin, signaling through the G protein-coupled receptor 54 (GPR54), has been proven as a pivotal regulator in the control of gonadotropin secretion and puberty. However, the impact of body energy status upon hypothalamic expression and function of this system remains unexplored. In this work, we evaluated the expression of KiSS-1 and GPR54 genes at the hypothalamus as well as the ability of kisspeptin-10 to elicit GnRH and LH secretion in prepubertal rats under short-term fasting. In addition, we monitored the actions of kisspeptin on food intake and the effects of its chronic administration upon puberty onset in undernutrition. Food deprivation induced a concomitant decrease in hypothalamic KiSS-1 and increase in GPR54 mRNA levels in prepubertal rats. In addition, LH responses to kisspeptin in vivo were enhanced, and its GnRH secretagogue action in vitro was sensitized, under fasting conditions. Central kisspeptin administration failed to change food intake patterns in animals fed ad libitum or after a 12-h fast. However, chronic treatment with kisspeptin was able to restore vaginal opening (in approximately 60%) and to elicit gonadotropin and estrogen responses in a model of undernutrition. In summary, our data are the first to show an interaction between energy status and the hypothalamic KiSS-1 system, which may constitute a target for disruption (and eventual therapeutic intervention) of pubertal development in conditions of negative energy balance.

Effects of KiSS-1 peptide, the natural ligand of GPR54, on follicle-stimulating hormone secretion in the rat

KiSS-1 was originally identified as a metastasis suppressor gene encoding an array of structurally related peptides, namely kisspeptins, which acting through the G protein-coupled receptor GPR54 are able to inhibit tumor progression. Unexpectedly, a reproductive facet of this newly discovered system has recently arisen, and characterization of the role of the KiSS-1/GPR54 system in the neuroendocrine control of gonadotropin secretion has been initiated. However, such studies have been so far mostly restricted to LH, and very little is known about the actual contribution of this system in the regulation of FSH release. To address this issue, the effects of KiSS-1 peptide on FSH secretion were monitored in vivo and in vitro under different experimental conditions. Intracerebroventricular administration of KiSS-1 peptide significantly stimulated FSH secretion in prepubertal and adult rats. Yet, dose-response analyses in vivo demonstrated an ED(50) value for the FSH-releasing effects of KiSS-1 of 400 pmol, i.e. approximately 100-fold higher than that of LH. In addition, systemic (ip and iv) injection of KiSS-1 significantly stimulated FSH secretion in vivo. However, KiSS-1 failed to elicit basal FSH release directly at the pituitary level, although it moderately enhanced GnRH-stimulated FSH secretion in vitro. Finally, mechanistic studies revealed that the ability of KiSS-1 to elicit FSH secretion was abolished by the blockade of endogenous GnRH actions, but it was persistently observed in different models of leptin insufficiency and after blockade of endogenous excitatory amino acid and nitric oxide pathways, i.e. relevant signals in the neuroendocrine control of gonadotropin secretion. In summary, our results extend previous recent observations on the role of KiSS-1 in the control of LH secretion and provide solid evidence for a stimulatory effect of KiSS-1 on FSH release, acting at central level. Overall, it is proposed that the KiSS-1/GPR54 system is a novel, pivotal downstream element in the neuroendocrine network governing gonadotropin secretion.

Characterization of the potent luteinizing hormone-releasing activity of KiSS-1 peptide, the natural ligand of GPR54

Loss-of-function mutations of the gene encoding GPR54, the putative receptor for the KiSS-1-derived peptide metastin, have been recently associated with hypogonadotropic hypogonadism, in both rodents and humans. Yet the actual role of the KiSS-1/GPR54 system in the neuroendocrine control of gonadotropin secretion remains largely unexplored. To initiate such analysis, the effects of KiSS-1 peptide on LH secretion were monitored using in vivo and in vitro settings under different experimental conditions. Central intracerebroventricular administration of KiSS-1 peptide potently elicited LH secretion in vivo over a range of doses from 10 pmol to 1 nmol. The effect of centrally injected KiSS-1 appeared to be mediated via the hypothalamic LHRH. However, no effect of central administration of KiSS-1 was detected on relative LHRH mRNA levels. Likewise, systemic (i.p. and i.v.) injection of KiSS-1 markedly stimulated LH secretion. This effect was similar in terms of maximum response to that of central administration of KiSS-1 and might be partially attributed to its ability to stimulate LH secretion directly at the pituitary. Finally, the LH-releasing activity of KiSS-1 was persistently observed after blockade of endogenous excitatory amino acid and nitric oxide pathways, i.e. relevant neurotransmitters in the neuroendocrine control of LH secretion. In summary, our results provide solid evidence for a potent stimulatory effect of KiSS-1 on LH release, acting at central levels (likely the hypothalamus) and eventually at the pituitary, and further document a novel role of the KiSS-1/GPR54 system as a relevant downstream element in the neuroendocrine network governing LH secretion.

Ghrelin inhibits the proliferative activity of immature Leydig cells in vivo and regulates stem cell factor messenger ribonucleic acid expression in rat testis

Ghrelin has emerged as putative regulator of an array of endocrine and nonendocrine functions, including cell proliferation. Recently, we provided evidence for the expression of ghrelin in mature, but not in undifferentiated, Leydig cells of rat and human testis. Yet testicular actions of ghrelin, other than modulation of testosterone secretion, remain unexplored. In the present study we evaluated the effects of ghrelin on proliferation of Leydig cell precursors during puberty and after selective elimination of mature Leydig cells by treatment with ethylene dimethane sulfonate. In these settings, intratesticular injection of ghrelin significantly decreased the proliferative activity of differentiating immature Leydig cells, estimated by 5-bromodeoxyuridine labeling. This response was selective and associated, in ethylene dimethane sulfonate-treated animals, with a decrease in the mRNA levels of stem cell factor (SCF), i.e. a key signal in spermatogenesis and a putative regulator of Leydig cell development. Thus, the effects of ghrelin on SCF gene expression were evaluated. In adult rats, ghrelin induced a significant decrease in SCF mRNA levels in vivo. Such an inhibitory action was also detected in vitro using cultures of staged seminiferous tubules. The inhibitory effect of ghrelin in vivo was dependent on proper FSH input, because it was detected in hypophysectomized rats only after FSH replacement. Overall, it is proposed that acquisition of ghrelin expression by Leydig cell precursors during differentiation may operate as a self-regulatory signal for the inhibition of the proliferative activity of this cell type through direct or indirect (i.e. SCF-mediated) mechanisms. In addition, we present novel evidence for the ability of ghrelin to modulate the expression of the SCF gene, which may have implications for the mode of action of this molecule in the testis as well as in other physiological systems.

Advanced vaginal opening and precocious activation of the reproductive axis by KiSS-1 peptide, the endogenous ligand of GPR54

The awakening of the gonadotrophic axis at puberty is the end-point of a complex cascade of sex developmental events that leads to the attainment of reproductive capacity. Recently, loss-of-function mutations of the gene encoding GPR54, the putative receptor for the KiSS-1-derived peptide metastin, have been linked to hypogonadotrophic hypogonadism, both in rodents and humans. However, the actual role of the KiSS-1/GPR54 system in the timing of puberty onset remains unexplored. We report herein that chronic central administration of KiSS-1 peptide to immature female rats induced the precocious activation of the gonadotrophic axis, as estimated by advanced vaginal opening, elevated uterus weight, and increased serum levels of luteinizing hormone (LH) and oestrogen. The central effect of KiSS-1 upon LH release appeared to be mediated via the hypothalamic LH-releasing hormone. In contrast, despite the well-documented permissive role of body fat stores and the adipocyte-derived hormone leptin in puberty maturation, acute activation of the gonadotrophic axis by KiSS-1 was persistently observed in pubertal animals under food deprivation, after central immunoneutralization of leptin, and in a model of leptin resistance. Overall, the present results, together with our recent data on maximum expression of KiSS-1 and GPR54 genes in the hypothalamus at puberty, provide novel evidence for a role of the KiSS-1 system as a downstream element in the hypothalamic network triggering the onset of puberty.

Developmental and hormonally regulated messenger ribonucleic acid expression of KiSS-1 and its putative receptor, GPR54, in rat hypothalamus and potent luteinizing hormone-releasing activity of KiSS-1 peptide

The gonadotropic axis is centrally controlled by a complex regulatory network of excitatory and inhibitory signals that is activated at puberty. Recently, loss of function mutations of the gene encoding G protein-coupled receptor 54 (GPR54), the putative receptor for the KiSS-1-derived peptide metastin, have been associated with lack of puberty onset and hypogonadotropic hypogonadism. Yet the pattern of expression and functional role of the KiSS-1/GPR54 system in the rat hypothalamus remain unexplored to date. In the present work, expression analyses of KiSS-1 and GPR54 genes were conducted in different physiological and experimental settings, and the effects of central administration of KiSS-1 peptide on LH release were assessed in vivo. Persistent expression of KiSS-1 and GPR54 mRNAs was detected in rat hypothalamus throughout postnatal development, with maximum expression levels at puberty in both male and female rats. Hypothalamic expression of KiSS-1 and GPR54 genes changed throughout the estrous cycle and was significantly increased after gonadectomy, a rise that was prevented by sex steroid replacement both in males and females. Moreover, hypothalamic expression of the KiSS-1 gene was sensitive to neonatal imprinting by estrogen. From a functional standpoint, intracerebroventricular administration of KiSS-1 peptide induced a dramatic increase in serum LH levels in prepubertal male and female rats as well as in adult animals. In conclusion, we provide novel evidence of the developmental and hormonally regulated expression of KiSS-1 and GPR54 mRNAs in rat hypothalamus and the ability of KiSS-1 peptide to potently stimulate LH secretion in vivo. Our current data support the contention that the hypothalamic KiSS-1/GPR54 system is a pivotal factor in central regulation of the gonadotropic axis at puberty and in adulthood.

[(18)F]-FDG PET and localized fibrous mesothelioma

The aim of this article is to present our experience with positron emission tomography (PET) and localized fibrous mesothelioma and to review the literature on this issue. During the past five years we found three patients with a complete clinical history who underwent a CT scan of the thorax and (18)F-fluorodeoxyglucose positron emission tomography ([(18)F]-FDG-PET) and were diagnosed with localized fibrous mesothelioma. Two of the patients were asymptomatic men and the third was a woman with chest pain. The standardized uptake value was 2.1 in one case, and in the other two an absence of FDG uptake was seen. All three had complete resection of the tumor, and in one case the presurgery diagnosis was adenocarcinoma. In one patient the tumor relapsed twice, and the other two patients are alive without any evidence of disease. The value of FDG-PET in the differential diagnosis of pulmonary and pleural abnormalities has gained ground during the last few years. As in most benign tumors, the FDG uptake is usually low (< 2.5) in the localized fibrous mesothelioma. However, more studies are necessary to define the role of FDG-PET in assessing this tumor.

Chromophore-modified bis-naphthalimides: synthesis and antitumor activity of bis-dibenz[de,h]isoquinoline-1,3-diones

The bis-dibenz[de,h]isoquinoline-1,3-diones are a new series of antitumor agents that consist of two chromophores bridged by an alkylamino linker. In the present study we have explored the effect produced by the presence of two dibenz[de,h]isoquinoline-1,3-dione moieties with different polyamine chains on cellular cytotoxicity. Bis-dibenz[de,h]isoquinoline-1,3-diones with the bridge (CH2)2-NH-(CH2)n-NH-(CH2)2, where n = 2-5, showed optimum cytotoxicity with IC50's around 10 nM. Compound 16, which has the (CH2)2-NH-(CH2)3-NH-(CH2)2 bridge, altered DNA mobility and topoisomerase I and II activity at approximately 5 microM. When tested in vivo, compound 16 increased the median survival time of mice implanted with M5076 with an optimum %T/C of 154% and produced cures in 50% of mice implanted with Lox melanoma.

Bis-naphthalimides 3: synthesis and antitumor activity of N,N'-bis[2-(1,8-naphthalimido)-ethyl] alkanediamines

The bis-naphthalimides are a new class of antitumor agent. Previously, we have described initial synthetic series which established that two naphthalimide chromophores joined by polyamine linkers can produce agents with antitumor activity. We now extend these studies to describe the synthesis of a N,N'-bis[1,8-naphthalimido)-ethyl]alkanediamine series and examine the alkyl linker and chromophore substitution requirements for optimal antitumor activity. As a result, a bis-naphthal-imidoethyl derivative with no chromophore substitution and a NH-(CH2)3-NH bridge was identified. This agent (LU 79553) had both potent cellular cytotoxicity (IC50 = 0.014 microM) and was curative against MX-1 tumors grown in athymic mice. It has now been selected for clinical development.

Synthesis, structure and antitumor activity of new benz[d,e]isoquinoline-1,3-diones

New benz[d,e]isoquinoline-1,3-diones related to mitonafide (CAS 54824-17-8) and amonafide (CAS 69408-81-7) with double substitution on the chromophore and branched side chains have been synthesized and their biological activity determined. Molecular modeling studies of 3a based on X-ray crystallographic data of mitonafide have shown that the aromatic system intercalates between GC steps of DNA. The in vitro cytotoxic test data using CX-1 and LX-1 cells showed higher cytotoxic activities in disubstituted derivatives compared to both lead compounds. Some of the compounds have been selected for in vivo test using L1210 tumor cells and CX-1 cells. Two of them (3b and 3j) have shown promising activity as good candidates for clinical development.