Pharmacokinetics of etravirine in HIV-infected patients concomitantly treated with rifampin for tuberculosis.

Etravirine is metabolized by three cytochrome P450 enzymes that are in turn induced by rifampin. Consequently, co-administration of etravirine and rifampin is not recommended. To date, however, no clinical studies exploring the drug-drug interaction of this combination have been conducted. Here we report two cases of off-label etravirine use concurrently with antitubercular treatment, dictated by the unavailability of other treatments. Plasma drug concentrations were monitored by regular measurements. Our results appear to confirm the increased metabolism of etravirine through the induction of cytochrome P450 enzymes, but the adequacy of drug levels in all of the measurements and subsequent virological suppression suggest that this drug interaction may not be clinically relevant.

Stress-related biomarkers of dream recall and implicit memory under anaesthesia.

The aim of this study was to investigate whether auditory presentation of a story during general anaesthesia might influence stress hormone changes and thus affecting dream recall and/or implicit memory. One hundred and ten patients were randomly assigned either to hear a recording of a story through headphones or to have routine care with no auditory recording while undergoing laparoscopic cholecystectomy. Anaesthesia was standardised. Blood samples for cortisol and prolactin assays were collected 20 min before anaesthesia and 5 min after pneumoperitoneum. Dream recall and explicit/implicit memory were investigated upon awakening from anaesthesia and approximately 24 h after the end of the operation. Auditory presentation was associated with lower intra-operative serum prolactin concentration compared with control (p = 0.0006). Twenty-seven patients with recall of dreaming showed higher intra-operative prolactin (p = 0.004) and lower cortisol (p = 0.03) concentrations compared with those without dream recall. The knowledge of this interaction might be useful in the quest to ensure postoperative amnesia.

Relationship between antiretroviral plasma concentration and emergence of HIV-1 resistance mutations at treatment failure.

PURPOSE: The relationship between antiretroviral pharmacokinetic exposure and acquisition of human immunodeficency virus-1 (HIV-1) drug resistance mutations (DRM) is not fully understood. The aim of this study was to investigate whether antiretroviral plasma concentration could predict the emergence of DRM at treatment failure. METHODS: The study cohort comprised retrospectively selected patients with failing antiretroviral regimens for whom a protease inhibitor (PI) or non-nucleoside reverse transcriptase inhibitor (NNRTI) trough concentration measurement (TDM) had been obtained before failure, a genotypic resistance test (GRT1) had been performed before the TDM, and a genotypic resistance test (GRT2) had been performed at therapeutic failure. Drug levels were classified as undetectable/detectable or subtherapeutic/therapeutic according to limits of quantification of a high-performance liquid chromatography-ultraviolet assay or pre-defined efficacy thresholds, respectively. The number of DRM acquired at treatment failure was evaluated by comparing the results of the GRT2 and GRT1. RESULTS: A total of ten and 57 failure episodes occurred among our patients on NNRTI-based and PI-based regimens, respectively, and included in the evaluation. PI concentration was subtherapeutic in 28.1% of patients, among which the levels were undetectable in 21.1%. Twenty-five (43.9%) patients acquired at least one new PI-DRM according to the GRT2. Patients with undetectable PI levels showed a lower emergence of PI-DRM (minor + major) than those with detectable levels (8.3 vs. 53.3%, p = 0.007). Multivariate analysis confirmed that undetectable PI levels were independent negative predictors of DRM selection. NNRTI measurements were subtherapeutic in 2/10 (20%) patients. NNRTI-DRM were acquired by all patients regardless of NNRTI levels. CONCLUSIONS: A PI measurement showing undetectable drug levels prior to treatment failure predicted the lack of emergence of PI-DRM at failure. These results suggest that PI levels can help clinicians interpret the reasons for treatment failure and guide the type of interventions needed.

The safety profile of probiotic VSL#3®. A meta-analysis of safety data from double-blind, randomized, placebo-controlled clinical trials.

The article "The safety profile of probiotic VSL#3®. A meta-analysis of safety data from double-blind, randomized, placebo-controlled clinical trials", by V. Panetta, A. Bacchieri, S. Papetti, E. De Stefani, P. Navarra, published in Eur Rev Med Pharmacol Sci 2020; 24 (2): 963-973-DOI: 10.26355/eurrev_202001_20082-PMID: 32017005, has been retracted based on commentary received from a new set of reviewers.  The authors will be able to resubmit a new article addressing the reviewers' comments for the Journal's consideration. The Publisher apologizes for any inconvenience this may cause. https://www.europeanreview.org/article/20082.

Compassionate drug uses and saving for the national health system: the case study of Fondazione Policlinico Gemelli.

OBJECTIVE: Compassionate Drug Use (CDU) allows patients with a specific disease and no further treatment option to access unauthorized treatments. In this study, we analyzed the requests of CDU approved by the Ethics Committee of Fondazione Policlinico Gemelli in the period January 1, 2018-June 30, 2021. We also estimated the economic impact of CUs. MATERIALS AND METHODS: CDU requests were analyzed by year, by frequency and by regulatory status of the medicines requested. If an ex-factory price was available at the cutoff date of June 30, 2021, we estimated what would have been the costs for the National Health System (NHS) if the price was already negotiated at the time of CDU request. RESULTS: In the study period, 463 CDU requests were processed by the Ethics Committee. The number of requests increase linearly from 45 in 2018 to an estimated number of 260 in 2021. The requests included 68 medicines or combinations of medicines; 16 products out of 68 accounted for 75% of all requests. For 7 of these 16 highly requested treatments, accounting for 110 requests out of 463, it was possible to estimate the costs of therapies according to their ex-factory prices. If these products were to be purchased by the NHS, the estimated cost was € 5.472.225. CONCLUSIONS: The access to unauthorized drugs through CDUs is undergoing a huge increase in the last few years. Such increase meets the ethical need to provide patients with the most recent, often innovative, therapeutic options.

Relationship between injection site reactions and different adalimumab formulations. Analysis of the adverse events reported in Italy in the period 2016-2019.

OBJECTIVE: The adalimumab originator Humira® introduced a new citrate-free formulation in 2016, before the patent expiry that occurred in the European Union in October 2018. Some of the adalimumab biosimilars that were subsequently marketed are citrate-free, while others are not. Since citrate as an excipient is associated with pain at the injection site, recent anecdotical reporting in Italy raised the issue of possible prescription biases related to the differences in formulation existing among the various adalimumab products. In this study, we analyzed the data obtained from the 'Rete Nazionale di Farmacovigilanza' (Pharmacovigilance National Network) to investigate whether, and to what extent, the differences in the formulation of the various adalimumab versions had an impact on the rate of injection site reactions reported in Italy in the period 2016-2019. MATERIALS AND METHODS: A search was conducted based on 3 search criteria: (1) time frame; (2) suspected drugs, and (3) adverse reaction type. Reports classified in the System Organ Class "Administration site conditions" were analyzed by year, product, and type of adverse event (whether including or not 'pain'). Data were reported both as absolute numbers, as well as signaling rates, considering the consumption data expressed as defined daily doses (DDD). RESULTS: We found that: (1) The change in Humira® formulation introduced in august 2016 was followed by a decrease in the reports of injection site reactions (from 45 in 2016 to 12, 12 and 8 in 2017, 2018, and 2019, respectively); (2) after the introduction of biosimilars during 2018, in 2019 a marked shift in reporting toward biosimilars was observed (52 out of 60; 87%). CONCLUSIONS: While the decrease in Humira® reports is consistent with the improved tolerability of the new formulation, the huge increase in biosimilar reporting may be only in part explained by the differences in formulation and cannot be accounted for by a parallel increase in exposure, since 58.3% of total DDDs provided in 2019 were still attributed to Humira®.

Effects of remifentanil on human C20 microglial pro-inflammatory activation.

OBJECTIVE: Remifentanil (RF) is a potent short-acting µ-opioid receptor agonist. Although preferred for its unique pharmacokinetics, the clinical use may be limited by hyperalgesia. Preclinical studies have shown a potential role of microglia on the development of hyperalgesia, with limited and conflicting evidence on RF. Considering the role of microglia in the initiation and maintenance of brain inflammation and their different responses among species, we aimed at characterizing RF effects on human adult microglia in vitro. MATERIALS AND METHODS: RF was tested at clinically relevant concentrations on the human microglial C20 cell line. Expression and release of interleukin-6 (IL-6) and brain derived neurotrophic factor (BDNF) were assessed under basal and inflammatory conditions. RESULTS: The expression and secretion of IL-6 significantly increased in C20 cells in response to pro-inflammatory cytokines. RF did not modify this response neither under basal nor under inflammatory conditions. No toxicity due to RF was detected. The drug displayed a modest stimulatory effect on the production of BDNF. CONCLUSIONS: Although RF does not exert direct pro-inflammatory actions on human adult microglia, its effects on BDNF, a crucial mediator of pain transmission, suggest a possible role on neuroinflammation and pain perception.

Mid-dosing interval concentration of atazanavir and virological outcome in patients treated for HIV-1 infection.

OBJECTIVES: We investigated the clinical significance of monitoring the mid-dosing interval atazanavir (ATV) concentration (measured 12 +/- 2 h after intake; C(12 h)) in patients taking this drug once daily in the evening. METHODS: We retrospectively selected HIV-infected patients harbouring ATV-susceptible virus who underwent therapeutic drug monitoring (TDM) of ATV C(12 h) during routine out-patient visits, and we correlated C(12 h) to the 24-week virological response and toxicity. RESULTS: A total of 115 plasma samples from 86 patients (76.7% with baseline HIV RNA<50 HIV-1 RNA copies/mL) were analysed. ATV plasma concentrations showed high inter-individual variability. ATV plasma levels were higher in samples obtained from patients taking boosted regimens (P<0.001) and not concomitantly receiving acid-reducing agents (P=0.007). In a multivariate model, ritonavir boosting, use of acid-reducing agents and liver cirrhosis showed an independent association with ATV level. Virological response at 24 weeks was observed for 94 of the 115 samples (81.7%). We identified a concentration cut-off of 0.23 mg/L which predicted virological response at 24 weeks: samples with a C(12 h)< or =0.23 mg/L showed virological failure in 41.2% of cases, whereas samples with a C(12 h)>0.23 mg/L showed virological failure in 14.3% of cases (P=0.021). In multivariate analysis, C(12 h)>0.23 mg/L was an independent predictor of virological response [odds ratio (OR) 4.23, P=0.031]. ATV levels correlated with concomitant unconjugated bilirubin levels (r=0.223, P=0.037), but a concentration cut-off predictive of moderate/severe hyperbilirubinaemia could not be identified. CONCLUSIONS: We identified a C(12 h) efficacy threshold that predicted virological response; this could be useful for morning TDM in selected subjects receiving ATV in the evening. Results must be interpreted with caution given the retrospective design of the study.

The safety profile of probiotic VSL#3®. A meta-analysis of safety data from double-blind, randomized, placebo-controlled clinical trials.

OBJECTIVE: A high-concentration of a multi-strain probiotic mixture, VSL#3® is widely used 'whenever it is useful to promote the balance of intestinal flora'. As a food supplement, VSL#3® has been so far scarcely investigated on the aspect of safety. To fill this gap, in this paper, we analyzed the adverse events (AEs) recorded during the conduct of three (3) double-blind, randomized, placebo-controlled trials carried out to explore the efficacy of VSL#3® in various clinical settings. Data from a large open-label observational trial were also considered. MATERIALS AND METHODS: All trials included in the analysis were carried out according to good clinical practice (GCP) rules. AEs were classified by System Organ Class (SOC), Preferred Term (PT) and frequency. Differences vs. placebo control were considered as statistically significant if the p-value was < 0.05. RESULTS: A total of 120 patients were analyzed, 70 patients being included in the randomized controlled trials. In this population, 45 patients had at least one AE, 20 (64.5%) in the placebo group and 25 (64.1%) in the VSL#3® group. 29 patients had at least one related AE, 14 (45.2%) and 15 (38.5%) in the two treatment groups, respectively. Only one AE was assessed as serious, i.e., Foetal malformation, which occurred in the placebo group and was considered unrelated. No significant difference was found between VSL#3® and placebo for any of the SOC considered, with the exception of Injury, poisoning and procedural complications, which was in favor of VSL#3®. CONCLUSIONS: Based on GCP-quality data from clinical trials, we conclude that VSL#3® is a safe and well-tolerated agent.

Dyslipidemia can reduce the immunosuppressive effects of cyclosporine.

AIMS: Dyslipidemia is a significant risk factor for the development of atherosclerotic disease and of chronic allograft rejection. Few data are available on the effects of dyslipidemia on the immunosuppressive action of immunosuppressive agents. We investigate the in vitro effects of lipids solution on the immunosuppressive action of cyclosporine (CsA). METHODS: Peripheral blood mononuclear cells (PBMC) were PHA or OKT3 activated in vitro with/without different concentrations of Intralipid solution (INT, range 0.5% to 15%). CsA inhibition of activation was measured after a 3 day incubation, by adding H3-thimidine. The intracellular concentration of CsA was measured by radioimmunoassay and related to the CsA inhibitory effects. RESULTS: Increasing INT concentration in the medium, CsA inhibition of PBMC activation by PHA or OKT3 was reduced from 72+/-13% to 8+/-2% and from 80+/-10% to 18+/-3%, respectively. A significant reduction of the intracellular CsA concentration was also evident with increasing INT concentrations and was related to the inhibitory activity of CsA. CONCLUSIONS: These results suggest that dyslipidemia may reduce the availability of intracellular CsA concentration to inhibit the immune activation process and may explain the relationship between dyslipidemia and chronic allograft loss.

[Health and growth: a brief review of the literature]. / Salute e crescita economica: una breve rassegna della letteratura.

Improving health around the world is an important social objective, which provides direct payoffs in terms of longer and better lives. There is also a large consensus that improving health can have equally large indirect payoffs through accelerating economic development. The role that health conditions play in affecting growth is mainly analyzed via two channels: the direct labour productivity effect and the indirect incentive effect. The labour productivity hypothesis asserts that individuals who are healthier have higher returns to labour input. This is well tested in the empirical literature with mixed conclusions. The incentive effect is borne of the theoretical literature, and individuals who are healthier and have a greater life expectancy will have the incentive to invest in education as the time horizon over which returns can be earned is extended. Education is the driver of economic growth, and thus health plays an indirect role. Other minor channels have developed in the literature through which health affect economic development. However, although cross-country empirical works show a strong correlation between measures of health (for example, life expectancy) and economic growth, a causal effect of health and disease on economic development has not been established in the literature. A recent study challenges the view that different health conditions explain cross-country income differences. This study suggests that an improvement in mortality rate due to more effective public health measures and the introduction of new chemicals and drugs starting in the 1940s determines an increase in the population size which in turn reduces income per capita and economic growth.

Expression of iNOS, CD163 and ARG-1 taken as M1 and M2 markers of microglial polarization in human glioblastoma and the surrounding normal parenchyma.

Microglia and macrophages appear to be the most common cells in the GBM microenvironment. In the present study we investigated the status of macrophages/microglia activation in surgical specimens from 41 patients diagnosed with grade IV GBM. For each patient we analyzed both the center of tumor and the parenchyma surrounding the tumor. The specimens were stained for: i) IBA1, a 17-kDa EF hand protein specifically expressed in microglia/macrophages ii) CD163, a cell surface antigen associated with M2 phenotype; iii) iNOS, taken as a functional marker of M1 phenotype, and iv) ARG-I, taken as a functional marker of M2 phenotype. Staining was scored in a double-blinded score on a scale from 0 to 5. Our results suggest that CD163 expression is higher within the tumor than in surrounding periphery in both male and female patients; while iNOS is higher within the tumor in males, no significant difference was found for ARG-1. In addition, analyzing the data in TGCA database, we found that CD163 expression was significantly and inversely correlated with mean survival times, with average survival times ranging from 448days in patients having low expression, to 319 in mid, and 353 in patients with high CD163 expressing tumors. In contrast, no significant association was found between survival time and ARG-1 or iNOS expression.

Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy.

OBJECTIVE: The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectomy. PATIENTS AND METHODS: Patients did not receive any pre-anesthetic medication. Anesthesia induction was standardized. Anesthesia maintenance was performed with inhaled sevoflurane at age-adjusted 1.0 minimum alveolar concentration and intravenous remifentanil at infusion rate ranging from 0.1 to 0.4 mcg/kg/min. Blood samples were withdrawn before anesthesia induction and 5 min after achieving a pneumoperitoneum pressure of 12 mmHg. Correlation analyses were performed to evaluate the relationship between measured blood remifentanil concentrations, CORT or PRL ratio (intraoperative/preoperative value) and remifentanil dose delivered by the pump. RESULTS: A significant inverse correlation was found between CORT ratio and measured blood remifentanil concentration (p=0.03) or planned remifentanil dose (p=0.04). No correlations were found between blood remifentanil concentration and PRL ratio (p=0.83). CONCLUSIONS: Our data suggest that the CORT response to surgical stress is more efficiently counteracted by increased blood remifentanil concentration.

Electromotive versus passive diffusion of mitomycin C into human bladder wall: concentration-depth profiles studies.

The objectives of these investigations were: (a) to make a preliminary study to assess concentration-depth profiles of mitomycin C (MMC) in the bladder wall at specified time intervals after passive diffusion (PD); and (b) to conduct a major study to compare concentration-depth profiles after PD and electromotive drug administration (EMDA) of MMC. Full thickness sections of viable human bladder wall were placed in two-chamber cells with urothelium exposed to donor compartments containing 40 mg of MMC in 100 ml of 0.96% NaCl solutions and with serosa-facing receptor compartments containing 0.9% NaCl solutions. In the preliminary study during each of nine experimental sessions, five sections of bladder wall were individually exposed to MMC for either 5, 15, 30, 45, or 60 min. In the major study, an anode and a cathode were sited in the donor and receptor compartments, and 14 paired experiments--current (20 mA)/no current--were conducted over a 30-min period. Bladder wall sections were cut serially into 40-microm slices parallel to the urothelium and analyzed by high-performance liquid chromatography for MMC concentration (microg/g wet tissue weight). Tissue viability and morphology and MMC stability were assessed by trypan-blue exclusion test, histological examination, and mass spectrometry analysis. In the preliminary study (PD only), mean MMC concentrations (microg) at 5, 15, 30, 45, and 60 min were: (a) for urothelium, 15.3, 60.0, 58.2, 60.1, and 57.8, respectively; (b) for lamina propria, 2.2, 18.9, 19.3, 16.1, and 17.3, respectively; and (c) for muscularis, 0.4, 2.0, 1.8, 1.3, and 2.4, respectively. In the comparative study, MMC concentrations and coefficients of variation (CV) were as follows: (a) for urothelium after PD, 46.6 with CV = 69%, and after EMDA, 170.0 with CV = 43% (P < 0.0001); (b) for lamina propria after PD, 16.1, with CV = 60%, and after EMDA, 65.6 with CV = 29% (P < 0.0001); and (c) for muscularis after PD, 1.9 with CV = 82%, and after EMDA, 15.9 with CV = 82% (P < 0.0005). All of the bladder sections remained viable, and the chemical structure of MMC was unchanged. It was concluded that EMDA significantly enhances MMC transport into all of the layers of the bladder wall, and sections of viable human bladder are a reliable tool for assessing different modes of drug delivery.

Lacosamide inhibits calcitonin gene-related peptide production and release at trigeminal level in the rat.

BACKGROUND: Several classes of drugs are effective in prevention and treatment of migraine, although they may differ among each other in their mode of action and in indications. One such class is represented by antiepileptics. Lacosamide is an approved antiepileptic drug that also shows antinociceptive activity in animal models, including analgesic efficacy in central and trigeminal pain. Calcitonin gene-related peptide (CGRP) is considered the main neuro-mediator of trigeminal signalling, playing an essential role in headache, migraine in particular. Here, we investigated the effects of lacosamide on CGRP signalling in both in vitro and ex vivo/vitro models in the rat. METHODS: We assessed: (1) CGRP released from brainstem explants at baseline or after pharmacological challenges; and (2) CGRP levels in brain areas after in vivo treatments with test drugs. RESULTS: We found that: (1) lacosamide inhibits CGRP release from brainstem explants under basal conditions as well as after stimulation by 56 mM KCl, 10 µM veratridine or 1 µM capsaicin; and (2) the i.p. administration of nitroglycerine produces an increase in CGRP levels in the brainstem and trigeminal ganglia, which is inhibited by a pre-treatment with lacosamide. CONCLUSIONS: These findings provide preliminary evidence suggesting that lacosamide is able to control pain transmission under conditions affecting the trigeminal system, such as migraine.

The generation of nitric oxide and carbon monoxide produces opposite effects on the release of immunoreactive interleukin-1beta from the rat hypothalamus in vitro: evidence for the involvement of different signaling pathways.

Both the cytokine, interleukin-1 (IL-1), and the gaseous neurotransmitters, nitric oxide (NO) and carbon monoxide (CO), have been implicated in the control of neuroendocrine functions, such as the release of CRH and luteotropic hormone-releasing hormone from the hypothalamus. Though increased levels of IL-1 in this brain region are unambiguously associated with enhanced CRH and reduced luteotropic hormone-releasing hormone release, the net effects of the two gases are still unclear, but in vivo and in vitro evidence suggests that the generation of NO and CO within the hypothalamus might counteract the stimulatory effects of IL-1 and bacterial lipopolysaccharide on the neuroendocrine stress axis. In this study, we have investigated the effects of NO and CO on the release of immunoreactive (ir)-IL-1beta from the rat hypothalamus in vitro. It was observed that the NO donor, sodium nitroprusside (SNP), stimulates ir-IL-1beta release under basal conditions, whereas the increase in CO levels obtained with hemin, the CO precursor through the heme oxygenase pathway, has no effect on basal ir-IL-1beta release but inhibits release stimulated by high K+ concentrations. The opposite effects of the two gases on cytokine release seemed to be caused by the activation of different signaling pathways, because: 1) SNP, but not CO-saturated solutions, is able to increase cyclic GMP levels in hypothalamic tissue; 2) CO-saturated solutions increase PGE2 production and release from the hypothalamic explants, whereas SNP has no effect; 3) SNP-stimulated ir-IL-1beta release is counteracted by a selective inhibitor of soluble guanylyl cyclase, LY 83583, but not by a cyclooxygenase inhibitor, indomethacin; and 4) conversely, indomethacin, but not LY 83583, reverses the inhibitory effect of hemin on K+-stimulated ir-IL-1beta release. It is concluded that NO and CO signal in the rat hypothalamus via the activation of soluble guanylyl cyclase and cyclooxygenase, respectively.

Carbon monoxide as a novel neuroendocrine modulator: inhibition of stimulated corticotropin-releasing hormone release from acute rat hypothalamic explants.

Although recent evidence suggests that the gas nitric oxide (NO) can modulate the secretion of corticotropin-releasing hormone (CRH) from acute rat hypothalamic explants, another gas, carbon monoxide (CO), has been suggested to play a role in neural signaling in the brain; CO may complement the activity of NO in long term potentiation. In this study, we have investigated whether CO shares with NO the ability to modify the release of CRH from the rat hypothalamus. Hemin, a specific CO precursor through the enzyme heme oxygenase (the enzymatic pathway synthesizing endogenous CO), was found to inhibit in a dose-dependent manner KCl-stimulated CRH release, with a maximal effect at 1 microM, while showing no effect on basal CRH secretion. The stimulation of CRH by interleukin-1 beta (100 ng/ml) was also significantly antagonized by hemin (1 microM). An inhibitor of heme oxygenase, zinc-protoporphyrin-9, had no effect on basal or stimulated CRH release up to a maximal dose of 10 microM. When hemin and zinc-protoporphyrin-9 were given together, the hemin-induced inhibition of CRH release was completely antagonized by the enzyme inhibitor. These findings provide evidence that endogenous CO may play a role in the control of CRH release; by analogy with NO, CO may represent a major new neuroendocrine modulator.

Morphine directly modulates the release of stimulated corticotrophin-releasing factor-41 from rat hypothalamus in vitro.

The actions of opioids and opiates on the hypothalamo-pituitary-adrenal axis are currently controversial. In the rat, morphine is reported to both stimulate and inhibit ACTH and corticosterone secretion, but the precise sites and mechanisms of these effects have remained unclear. To analyze further the hypothalamic actions of morphine, we have investigated its effect on hypothalamic fragments in vitro and measured the major CRF, CRF-41, by a specific RIA. The acute effects of morphine on both basal and stimulated ACTH release from dispersed pituitary cells were also investigated. Morphine (10(-8)-10(-6) M) did not significantly alter the basal secretion of CRF-41. However, similar concentrations of morphine inhibited CRF-41 release stimulated by norepinephrine in a dose-dependent manner. Similarly, morphine (10(-6) M) inhibited acetylcholine (10(-9) M)- and serotonin (10(-7) M)-stimulated CRF-41 release. The stimulatory effect on CRF-41 release induced by veratridine (10(-6) M) was inhibited by approximately 50% in the presence of morphine. KCl (28 nM)-mediated CRF-41 release was also significantly inhibited by morphine. Naloxone (10(-7)-10(-5) M) had no significant effect on either basal or norepinephrine-induced CRF-41 release, but reversed the inhibitory effect of morphine on norepinephrine-induced CRF-41 secretion in a dose-dependent manner. Morphine (10(-6)-10(-5) M) had no effect on either basal or CRF-41-stimulated ACTH release from dispersed pituitary cells. These data suggest that the predominant effect of morphine on hypothalamic CRF-41 release in vitro is suppression of the release induced by a variety of putative neurotransmitters and depolarizing agents. This inhibitory effect is reversed by naloxone, suggesting that it is mediated by opiate receptors, presumably situated directly on CRF-41 neurons.

Interleukins-1 and -6 stimulate the release of corticotropin-releasing hormone-41 from rat hypothalamus in vitro via the eicosanoid cyclooxygenase pathway.

It has previously been shown that interleukin-1 (IL-1) directly stimulates the release of CRH-41 from rat hypothalamus in vitro, suggesting that cytokines may mediate the effects of changes in immune state on the hypothalamo-pituitary adrenal axis (HPA). However, it is likely that several cytokines can cause changes in neuroendocrine function, and we have now investigated a series of others for central activity on the HPA: IL-2, IL-6, IL-8, tumor necrosis factor (cachectin), interferon-alpha 2, and interferon-gamma. The static rat hypothalamic incubation system used involves fresh hypothalamic explants with consecutive 20-min incubation, and estimation of CRH-41 concentrations in the medium by a specific RIA; the acute effects of cytokines on ACTH release from rat dispersed pituitary cells were also measured. IL-6 increased hypothalamic CRH-41 secretion in the range 10-100 U/ml, but had no effect on isolated median eminences incubated in vitro under the same conditions. IL-6 (1-1000 U/ml) also had no effect on the secretion of ACTH from freshly dispersed rat anterior pituitary cells when administered in 10-min pulses. The effects of both IL-1 and IL-6 were antagonized by blockade of the eicosanoid cyclooxygenase pathway, but not by lipooxygenase blockade. Neither IL-2 (1-10000 U/ml), IL-8 (0.1-10 nM), tumor necrosis factor (10-1000 U/ml), interferon-alpha 2 (10-1000 U/ml) nor interferon-gamma (10-1000 U/ml) had any effect on hypothalamic CRH-41 release or pituitary ACTH release. It is therefore concluded that IL-6, like IL-1, can exert a potent enhancing effect on the HPA by acutely stimulating the secretion of CRH-41 from the hypothalamus at a site above the level of the median eminence, at concentrations known to occur in human plasma and cerebrospinal fluid. These effects are probably mediated by cyclooxygenase products. Acute stimulatory effects of the other cytokines investigated on the HPA are unlikely to be exerted through changes in either CRH-41 or ACTH directly.

Interleukin-1 beta modulates the acute release of growth hormone-releasing hormone and somatostatin from rat hypothalamus in vitro, whereas tumor necrosis factor and interleukin-6 have no effect.

There is clear evidence for communication between the immune and neuroendocrine systems. However, the effect of cytokines as major immune mediators on the hypothalamic growth peptides, GHRH and somatostatin (SRIH), is not well established. To investigate a possible hypothalamic action of the cytokines interleukin-1 beta (IL-1), interleukin-6, and tumor necrosis factor-alpha, on the release of GHRH and SRIH, we used a previously validated acute rat hypothalamic explant system. IL-1 caused a pronounced dose-dependent stimulation of SRIH in the dose-range 1-100 U/ml (P less than 0.01). GHRH showed a slight, but significant, increase in response to IL-1 tested in the dose-range 10-100 U/ml. Similar studies with mediobasal hypothalamic (GHRH and SRIH) or median eminence (SRIH) fragments produced no change in either GHRH or SRIH release. The effects of IL-1 were antagonized by the cyclo-oxygenase inhibitor, indomethacin (10 micrograms/ml). Stimulation of GHRH and SRIH could not be blocked by the CRH-antagonist alpha-helical CRH (9-41) at 10(-6) M. Interleukin-6, in the dose range 10-100 U/ml, and tumor necrosis factor-alpha, in the dose range 10-10,000 U/ml, had no effect on the acute hypothalamic release of either GHRH or SRIH. It is concluded that IL-1 stimulates the acute hypothalamic release of GHRH and SRIH, and that this effect is mediated by cyclo-oxygenase products. The marked IL-1 stimulation of hypothalamic SRIH release may override the minor increase of GHRH increase, and may thus contribute to disturbances in growth seen in the presence of chronic inflammation.