Clinical characteristics and outcomes among hospitalised COVID-19 patients across epidemic waves in Spain: An unCoVer analysis

BACKGROUND AND OBJECTIVES

The COVID-19 pandemic had a significant impact in population health worldwide, and particularly in people with pre-existing chronic diseases. Early risk identification and stratification is essential to reduce the impact of future outbreaks of pandemic potential. This study aimed to comprehensively examine factors associated with COVID-19 mortality across the pandemic waves in Spain.

METHODS

A retrospective study analyzed the characteristics of 13,974 patients admitted to Spanish hospitals due to SARS-CoV-2 infection from 2020-01-28 to 2022-12-31. The demographic and clinical features of patients during hospitalization on each pandemic waves were analyzed.

MAIN FINDINGS

The findings highlight the heterogeneity of patient characteristics, comorbidities and outcomes, across the waves. The high prevalence of cardiometabolic diseases (53.9%) among COVID-19 patients emphasizes the importance of controlling these risk factors to prevent severe COVID-19 outcomes.

CONCLUSIONS

In summary, the study associate hospital mortality with factors such as advanced age and comorbidities. The decline in mortality after the 4th wave indicates potential influences like vaccination, viral adaptation, or improved treatments. Notably, dementia and cancer metastases emerge as critical factors linked to higher mortality, highlighting the importance of addressing these conditions in COVID-19 management and preparing for future challenges.

Bioavailability and systemic transport of oleanolic acid in humans, formulated as a functional olive oil

Evidence of the pharmacological activity of oleanolic acid (OA) suggests its potential therapeutic application. However, its use in functional foods, dietary supplements, or nutraceuticals is hindered by limited human bioavailability studies. The BIO-OLTRAD trial is a double-blind, randomized controlled study with 22 participants that received a single dose of 30 mg OA formulated as a functional olive oil. The study revealed that the maximum serum concentration of OA ranged from 500 to 600 ng mL-1, with an AUC0-∞ value of 2862.50 ± 174.50 ng h mL-1. Furthermore, we discovered a physiological association of OA with serum albumin and triglyceride-rich lipoproteins (TRL). UV absorption spectra showed conformational changes in serum albumin due to the formation of an adduct with OA. Additionally, we demonstrated that TRL incorporate OA, reaching a maximum concentration of 140 ng mL-1 after 2-4 hours. We conjecture that both are efficient carriers to reach target tissues and to yield high bioavailability.

Clinical Benefit of Bempedoic Acid in Randomized Clinical Trials

Bempedoic acid is a selective inhibitor of the adenosine triphosphate citrate lyase that reduces low-density lipoprotein cholesterol (LDLc) levels by 17% to 28%. Although the Evaluation of Major Cardiovascular Events in Patients With, or at High Risk for, Cardiovascular Disease Who Are Statin Intolerant Treated With Bempedoic Acid (CLEAR-OUTCOMES) trials demonstrated the efficacy on cardiovascular outcomes there is a controversy related to the possible net clinical benefit. Thereafter, we performed an intention-to-treat meta-analysis in line with recommendations from the Cochrane Collaboration and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. The primary outcome of the metanalysis was the incidence of major adverse cardiovascular events, defined by each study protocol. Secondary outcomes for the analyses were myocardial infarction, stroke, myocardial revascularization, cardiovascular death, and all-cause death. Results of 4 clinical trials evaluated contained a total of 17,324 patients; 9,236 received bempedoic acid for a median of 46.6 months. The mean baseline LDLc was 129.4 (22.8) mg/100 ml and treatment was associated with a mean LDLc reduction of 26.0 (12.6) mg/100 ml. Treatment with bempedoic acid significantly reduced the incidence of major adverse cardiovascular events (hazard ratio [HR] 0.88, 95% confidence interval [CI] 0.81 to 0.96), myocardial infarction (HR 0.76, 95% CI 0.66 to 0.89) and myocardial revascularization (HR 0.82, 95% CI 0.73 to 0.92); the crude incidence of stroke, cardiovascular or all-cause mortality were lower in patients in the bempedoic acid groups although no significant risk reduction was observed. No heterogeneity was observed in any of the end points. In conclusion, the metanalysis of the 4 clinical trials currently available with bempedoic acid provides reliable evidence of its clinical benefit with no signs of heterogeneity or harm.

Bioactive compounds in pomace olive oil modulate the inflammatory response elicited by postprandial triglyceride-rich lipoproteins in BV-2 cells

Modulation of microglial response could be a target to reduce neuroinflammation associated with Alzheimer's disease. In this study, we propose that lipophilic bioactive molecules present in pomace olive oil (POO), transported in triglyceride-rich lipoproteins (TRLs), are able to modulate microglial high-oleic sunflower oil (HOSO, points) or pomace olive oil (POO, stripes). In order to prove this hypothesis, a randomized crossover postprandial trial was performed in 18 healthy young women. POO was assayed in opposition to high-oleic sunflower oil (HOSO), a common dietary oil which shares with POO an almost identical fatty acid composition but lacks certain biomolecules with recognized antioxidant and anti-inflammatory activities. TRLs were isolated from blood at the baseline and 2 and 4 hours postprandially and used to treat BV-2 cells to assess their ability to modulate the microglial function. We found that the intake of POO leads to the constitution of postprandial TRLs that are able to modulate the inflammatory response in microglia compared to HOSO. TRL-derived POO reduced the release of pro-inflammatory cytokines (tumor necrosis factor-α, and interleukins 1β and 6) and nitric oxide and downregulated genes codifying for these cytokines and inducible nitric oxide synthase (iNOS) in BV-2 cells. Moreover, the ingestion of POO by healthy women slightly improved glycemic control and TRL clearance throughout the postprandial phase compared to HOSO. In conclusion, we demonstrated that consuming POO results in postprandial TRLs containing lipophilic bioactive compounds capable of regulating the inflammatory response prompted by microglial activation.

Randomized Trial of Anticoagulation Strategies for Noncritically Ill Patients Hospitalized With COVID-19

BACKGROUND

Prior studies of therapeutic-dose anticoagulation in patients with COVID-19 have reported conflicting results.

OBJECTIVES

We sought to determine the safety and effectiveness of therapeutic-dose anticoagulation in noncritically ill patients with COVID-19.

METHODS

Patients hospitalized with COVID-19 not requiring intensive care unit treatment were randomized to prophylactic-dose enoxaparin, therapeutic-dose enoxaparin, or therapeutic-dose apixaban. The primary outcome was the 30-day composite of all-cause mortality, requirement for intensive care unit-level of care, systemic thromboembolism, or ischemic stroke assessed in the combined therapeutic-dose groups compared with the prophylactic-dose group.

RESULTS

Between August 26, 2020, and September 19, 2022, 3,398 noncritically ill patients hospitalized with COVID-19 were randomized to prophylactic-dose enoxaparin (n = 1,141), therapeutic-dose enoxaparin (n = 1,136), or therapeutic-dose apixaban (n = 1,121) at 76 centers in 10 countries. The 30-day primary outcome occurred in 13.2% of patients in the prophylactic-dose group and 11.3% of patients in the combined therapeutic-dose groups (HR: 0.85; 95% CI: 0.69-1.04; P = 0.11). All-cause mortality occurred in 7.0% of patients treated with prophylactic-dose enoxaparin and 4.9% of patients treated with therapeutic-dose anticoagulation (HR: 0.70; 95% CI: 0.52-0.93; P = 0.01), and intubation was required in 8.4% vs 6.4% of patients, respectively (HR: 0.75; 95% CI: 0.58-0.98; P = 0.03). Results were similar in the 2 therapeutic-dose groups, and major bleeding in all 3 groups was infrequent.

CONCLUSIONS

Among noncritically ill patients hospitalized with COVID-19, the 30-day primary composite outcome was not significantly reduced with therapeutic-dose anticoagulation compared with prophylactic-dose anticoagulation. However, fewer patients who were treated with therapeutic-dose anticoagulation required intubation and fewer died (FREEDOM COVID [FREEDOM COVID Anticoagulation Strategy]; NCT04512079).

Early detection of anthracycline- and trastuzumab-induced cardiotoxicity: value and optimal timing of serum biomarkers and echocardiographic parameters

AIMS

To evaluate echocardiographic and biomarker changes during chemotherapy, assess their ability to early detect and predict cardiotoxicity and to define the best time for their evaluation.

METHODS AND RESULTS

Seventy-two women with breast cancer (52 ± 9.8 years) treated with anthracyclines (26 also with trastuzumab), were evaluated for 14 months (6 echocardiograms/12 laboratory tests). We analysed: high-sensitivity cardiac troponin T, NT-proBNP, global longitudinal strain (GLS), left ventricle end-systolic volume (LVESV), left ventricle end-diastolic volume (LVEDV), and left ventricular ejection fraction (LVEF). Cardiotoxicity was defined as a reduction in LVEF>10% compared with baseline with LVEF<53%. High-sensitivity troponin T levels rose gradually reaching a maximum peak at 96 ± 13 days after starting chemotherapy (P < 0.001) and 62.5% of patients presented increased values during treatment. NT-proBNP augmented after each anthracycline cycle (mean pre-cycle levels of 72 ± 68 pg/mL and post-cycle levels of 260 ± 187 pg/mL; P < 0.0001). Cardiotoxicity was detected in 9.7% of patients (mean onset at 5.2 months). In the group with cardiotoxicity, the LVESV was higher compared with those without cardiotoxicity (40 mL vs. 29.5 mL; P = 0.045) at 1 month post-anthracycline treatment and the decline in GLS was more pronounced (-17.6% vs. -21.4%; P = 0.03). Trastuzumab did not alter serum biomarkers, but it was associated with an increase in LVESV and LVEDV (P < 0.05). While baseline LVEF was an independent predictor of later cardiotoxicity (P = 0.039), LVESV and GLS resulted to be early detectors of cardiotoxicity [odds ratio = 1.12 (1.02-1.24), odds ratio = 0.66 (0.44-0.92), P < 0.05] at 1 month post-anthracycline treatment. Neither high-sensitivity troponin T nor NT-proBNP was capable of predicting subsequent cardiotoxicity.

CONCLUSIONS

One month after completion of anthracycline treatment is the optimal time to detect cardiotoxicity by means of imaging parameters (LVESV and GSL) and to determine maximal troponin rise. Baseline LVEF was a predictor of later cardiotoxicity. Trastuzumab therapy does not affect troponin values hence imaging techniques are recommended to detect trastuzumab-induced cardiotoxicity.

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&lt;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&lt;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&lt;0.001), triglycerides (−67.5 vs. −59.9, −56.1 and −54.4 mg/dL; p&lt;0.001)) and in reduction of blood pressure (PAS (−14.1 vs. −11.7, −10.4 and −10.4 mmHg; p&lt;0.001) and PAD (−4.5 vs −2.5, −2.1, −1.2 mmHg; p&lt;0.001)). Higher persistence to treatment in the CNIC- polypill cohort (72.1% vs. 62. 2%, 60.0% and 54.2%; p&lt;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&lt;0.001), visits to specialists (5.0 vs. 6.2, 6.5 and 7.3; p&lt;0.001), percentage of patients hospitalized (16.5% vs. 19.8%, 21.9% and 24.0%; p&lt;0.001) and days of hospitalization (2.3 vs. 3.4, 3.7 and 4.0; p&lt;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&lt;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) &gt;75, p50–75 and p&lt;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&gt;75) or discouraging (p&lt;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.

Hemogram as marker of in-hospital mortality in COVID-19

The clinical impact of COVID-19 disease calls for the identification of routine variables to identify patients at increased risk of death. Current understanding of moderate-to-severe COVID-19 pathophysiology points toward an underlying cytokine release driving a hyperinflammatory and procoagulant state. In this scenario, white blood cells and platelets play a direct role as effectors of such inflammation and thrombotic response. We investigate whether hemogram-derived ratios such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio and the systemic immune-inflammation index may help to identify patients at risk of fatal outcomes. Activated platelets and neutrophils may be playing a decisive role during the thromboinflammatory phase of COVID-19 so, in addition, we introduce and validate a novel marker, the neutrophil-to-platelet ratio (NPR).Two thousand and eighty-eight hospitalized patients with COVID-19 admitted at any of the hospitals of HM Hospitales group in Spain, from March 1 to June 10, 2020, were categorized according to the primary outcome of in-hospital death.Baseline values, as well as the rate of increase of the four ratios analyzed were significantly higher at hospital admission in patients who died than in those who were discharged (p<0.0001). In multivariable logistic regression models, NLR (OR 1.05; 95% CI 1.02 to 1.08, p=0.00035) and NPR (OR 1.23; 95% CI 1.12 to 1.36, p<0.0001) were significantly and independently associated with in-hospital mortality.According to our results, hemogram-derived ratios obtained at hospital admission, as well as the rate of change during hospitalization, may easily detect, primarily using NLR and the novel NPR, patients with COVID-19 at high risk of 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.

Carotid Plaque Burden by 3-Dimensional Vascular Ultrasound as a Risk Marker for Patients with Metabolic Syndrome

Our aim was to analyse the associations between carotid plaque burden (CPB), cardiovascular risk factors (CVRF), and surrogate markers of CV risk in subjects with metabolic syndrome (MetS). We consecutively included 75 asymptomatic outpatients with MetS components, <60 years old and non-smokers. We determined the presence of CVRF, left ventricular hypertrophy (LVH), carotid intima-media thickness (cIMT), albumin-creatinine ratio (ACR), coronary artery calcium score (CACS) and CPB by 3-dimensional vascular ultrasound (3DVUS) for comparison. A total of 50 (67%) subjects had MetS defined by harmonized criteria. A CPB >0 mm³ and a CACS >0 AU were the risk biomarkers most frequently observed (72% and 77%, respectively), followed by LVH (40%). CPB and CACS revealed association with cardiovascular risk (r = 0.308; p = 0.032 and r = 0.601 p < 0.01, respectively), and CPB also showed association with the burden of CVRF (r = 0.349; p = 0.014). CPB by 3DVUS was a prevalent CV risk marker, directly associated with CVRF and cardiovascular risk in MetS subjects.

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.

GC-FID determination and pharmacokinetic studies of oleanolic acid in human serum

Analytical interest of OA determination in human serum has increased owing to the increasing interest in pharmaceutical research by pharmaceutical properties. A simple, specific, precise and accurate GC method with flame ionization detector (FID) developed and validated for the determination of oleanolic acid (OA) in human serum (HS). To an aliquot of HS, internal standard was added and a combination of liquid-liquid extraction with a mixture of diethyl ether-isopropyl alcohol, filtration and consecutive GC resulted in separation and quantification of OA. The organic phase was analyzed using a GC system equipped with a 30 × 0.25 mm i.d. Rtx-65TG capillary column and FID detection. Total chromatographic time was 10 min and no interfering peaks from endogenous components in blank serum were observed. The OA/internal standard peak area ratio was linearly fitted to the OA concentration (r = 0.992) over the range 10-1500 ng/mL. The mean serum extraction recovery of OA was 96.7 ± 1.0% and the lower limit of quantification based on 5 mL of serum was 10.7 ng/mL. The intra-day coefficient of variation ranged from 1.3 to 3.6% and inter-day varied from 1.4 to 4.5%. The developed method was used to study the pharmacokinetics of OA after oral administration in humans. The assay was simple, sensitive, precise and accurate for the use in the study of the mechanisms of absorption and distribution of OA in humans.

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.

The influence of obesity on the assessment of carotid intima-media thickness

BACKGROUND

The assessment of carotid intima-media thickness (CIMT) may improve cardiovascular risk prediction. The optimal protocol for CIMT measurement is unclear. CIMT may be measured in the common carotid artery (CCA), carotid bifurcation (CB), and internal carotid artery (ICA), but measurements from CB and ICA are more difficult to obtain. We studied the influence of body mass index (BMI) and atheroma plaques on the capacity to obtain CIMT measurements at different carotid sites.

METHODS

Using an automatic system, CIMT was measured in 700 subjects aged 45-75, in the near and far walls of CCA, CB, and ICA bilaterally. The presence of atheroma plaques, BMI and vascular risk factors were recorded.

RESULTS

CIMT measurements in CCA were possible in all except one subject. It was not possible to obtain CIMT measurements at CB or ICA in 24.1% of normal weight and 58.8% of obese subjects. The likelihood of obtaining CIMT measurement at all carotid sites decreased as the BMI increased. Atheroma plaques in a carotid segment did not preclude CIMT measurement at this site.

CONCLUSIONS

CIMT measurements in distal carotid segments are more challenging in obese subjects. Measuring CIMT at CCA remains feasible in obese subjects and should be the primary endpoint in these subjects. Nevertheless, CB and ICA measurements, when feasible, would improve risk classification.

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.

Mitochondrial beta-cyanoalanine synthase is essential for root hair formation in Arabidopsis thaliana

Cyanide is stoichiometrically produced as a coproduct of the ethylene biosynthesis pathway and is detoxified by β-cyanoalanine synthase enzymes. The molecular and phenotypical analysis of T-DNA insertion mutants of the mitochondrial β-cyanoalanine synthase CYS-C1 suggests that discrete accumulation of cyanide is not toxic for the plant and does not alter mitochondrial respiration rates but does act as a strong inhibitor of root hair development. The cys-c1 null allele is defective in root hair formation and accumulates cyanide in root tissues. The root hair defect is phenocopied in wild-type plants by the exogenous addition of cyanide to the growth medium and is reversed by the addition of hydroxocobalamin or by genetic complementation with the CYS-C1 gene. Hydroxocobalamin not only recovers the root phenotype of the mutant but also the formation of reactive oxygen species at the initial step of root hair tip growth. Transcriptional profiling of the cys-c1 mutant reveals that cyanide accumulation acts as a repressive signal for several genes encoding enzymes involved in cell wall rebuilding and the formation of the root hair tip as well as genes involved in ethylene signaling and metabolism. Our results demonstrate that mitochondrial β-cyanoalanine synthase activity is essential to maintain a low level of cyanide for proper root hair development.

Pentacyclic triterpenoids from olive fruit and leaf

This work establishes a new procedure for the extraction and analysis of pentacyclic triterpenes, with which fruits and leaves from three Spanish olive cultivars ("Picual", "Hojiblanca", and "Arbequina") has been studied. The leaf contains important amounts of oleanolic acid (3.0-3.5% DW), followed by significant concentrations of maslinic acid and minor levels of ursolic acid, erythrodiol, and uvaol. The abundance and profile of triterpenoids change during the leaf ontogeny. In the fruit, triterpenes are exclusively located in the epicarp at concentrations 30-fold lower than that in the leaf. Maslinic acid is the main triterpenoid, only accompanied of oleanolic acid. Along the ripening the levels of these triterpenes decreased. All the analyzed leaves and fruits come from the same agricultural estate, with identical climate and culturing conditions. For this reason, the found differences could majorly be attributable to the genetic factors of the olive cultivars.

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.