Oncological treatment administration at end of life: a retrospective study.

Background: This work evaluated the proportion of patients who continue therapy until their last month of life or initiate a new therapy in the last 3 months of life (end of life [EOL]). Methods: Data for 486 patients were retrospectively collected. Results: In EOL, 205 (42.3%) received systemic therapy. Better performance status (last month overall response [OR]: 0.39; 95% CI: 0.25-0.60; p < 0.001; last 3 months OR: 0.47; 95% CI: 0.34-0.65; p < 0.001) and lack of activation of palliative care (last month OR: 0.26; 95% CI: 0.13-0.54; p < 0.001; last 3 months OR: 0.18; 95% CI: 0.10-0.32; p < 0.001) were associated with higher probability of EOL therapy. Conclusion: A non-negligible proportion of patients in real-life settings continue to receive systemic treatment in EOL.

Sleep inhibition induced by amyloid-ß oligomers is mediated by the cellular prion protein.

Sleep is severely impaired in patients with Alzheimer's disease. Amyloid-ß deposition in the brain of Alzheimer's disease patients is a key event in its pathogenesis and is associated with disrupted sleep, even before the appearance of cognitive decline. Because soluble amyloid-ß oligomers are the key mediators of synaptic and cognitive dysfunction in Alzheimer's disease and impair long-term memory in rodents, the first aim of this study was to test the hypothesis that amyloid-ß oligomers would directly impair sleep in mice. The cellular prion protein is a cell surface glycoprotein of uncertain function. Because cellular prion protein binds oligomeric amyloid-ß with high affinity and mediates some of its neurotoxic effects, the second aim of the study was to test whether amyloid-ß oligomer-induced sleep alterations were mediated by cellular prion protein. To address these aims, wild-type and cellular prion protein-deficient mice were given acute intracerebroventricular injections (on different days, at lights on) of vehicle and synthetic amyloid-ß oligomers. Compared to vehicle, amyloid-ß oligomers significantly reduced the amount of time spent in non-rapid eye movement sleep by wild-type mice during both the light and dark phases of the light-dark cycle. The amount of time spent in rapid eye movement sleep was reduced during the dark phase. Sleep was also fragmented by amyloid-ß oligomers, as the number of transitions between states increased in post-injection hours 9-24. No such effects were observed in cellular prion protein-deficient mice. These results show that amyloid-ß oligomers do inhibit and fragment sleep, and that these effects are mediated by cellular prion protein.

Efficacy of the DigniCap System in preventing chemotherapy-induced alopecia in breast cancer patients is not related to patient characteristics or side effects of the device.

BACKGROUND: The DigniCap System is an effective scalp cooling device for the prevention of chemotherapy-induced alopecia in early breast cancer patients. AIM: This prospective study was designed to confirm the efficacy and tolerability of the device, to explore potential factors associated with its efficacy and to collect data on patient perceptions and satisfaction. METHODS: Between January 2016 and June 2018, 163 early breast cancer patients eligible for adjuvant chemotherapy were enrolled. Hair loss was assessed using the Dean scale, where a score of 0-2 (hair loss ≤50%) was defined as successful. RESULTS: Hair preservation was successful in 57% of patients in the overall series. The proportion was even higher (81%) in the patient subgroup treated with a paclitaxel and trastuzumab regimen. Side effects (feeling cold, headache, head heaviness, scalp and cervical pain) were mild to moderate and did not correlate with the rate of hair loss. Lifestyle, anthropometric factors and hair characteristics failed to be associated with device efficacy. CONCLUSIONS: The DigniCap System was well tolerated and found to be effective in preventing alopecia in early breast cancer patients. Our study failed to identify factors other than type of chemotherapy regimen associated with hair preservation.

Febrile and sleep responses to an immune challenge are affected by trait aggressiveness in rats.

Sleep is altered in response to an immune challenge: non-rapid eye movement (NREM) sleep is increased and fragmented, REM sleep is inhibited. Sleep and immune response are affected by stress: several stressors inhibit sleep and increase waking time; stress-induced cortisol secretion affects the immune response, with immunosuppressive effects. Different levels of trait aggressiveness are associated with specific patterns of neuroendocrine and autonomic stress responsiveness. Aim of this study was to test the hypothesis that trait aggressiveness, by affecting response to stressors, modifies sleep alterations induced by the activation of the immune response. To this aim, rats were selected on the basis of their latency time to attack a male intruder in the resident-intruder test. Animals were instrumented for chronic recordings of sleep-wake activity and injected, intraperitoneally, with an immune challenge (250 µg/kg lipopolysaccharide - LPS, a component of gram-negative bacterial cell wall). Here we report that high aggressive (HA) rats responded to an immune challenge with a 24-h long increase in cortical brain temperature. During the first 12 post-injection hours, HA rats also responded with a prolonged increase in NREM sleep amount, and a 5-h long and continuous inhibition of REM sleep. In HA rats, the LPS-induced increase in the amount of time spent in NREM sleep was due to an increase in the number of episodes of this sleep phase, without any change in the bout duration. The LPS-induced REM sleep inhibition observed in HA rats was due to a decrease in both the number and duration of REM sleep bouts. In HA rats, during REM sleep, LPS administration significantly reduced the power of the EEG theta band. In non-aggressive (NA) rats, in response to LPS administration, cortical brain temperature was increased only for two hours, NREM sleep was unaffected, and REM sleep inhibition was scattered along the first 8 post-injection hours. The LPS-induced changes in the number of NREM sleep bouts of NA rats were limited to few and scattered hours, with a change in bout duration only in a single hour. A combination of decreases, in few hours, in both REM sleep bouts and their duration contributed to the REM sleep inhibition observed in NA rats. In NA rats, the power of EEG theta band was not modified, during REM sleep, by LPS administration. Gross motor activity was inhibited in both HA and NA rats. Results of this study show that trait aggressiveness affects febrile and sleep responses to an immune challenge.

Hepatoprotective effect of N-acetylcysteine in trabectedin-induced liver toxicity in patients with advanced soft tissue sarcoma.

PURPOSE: Trabectedin is one of the few active agents in soft tissue sarcoma (STS) but hepatotoxicity is frequent and represents a dose-limiting factor. Protective strategies aiming at counteracting this important side effect have a crucial clinical impact. Due to its antioxidant properties, N-acetylcysteine (NAC) has a recognized hepatoprotective effect and this provides the rationale for testing NAC in the management of trabectedin-induced hepatotoxicity. METHODS: Patients with recurrent or metastatic soft tissue sarcoma, consecutively observed at our institution, who were considered eligible to trabectedin, received concomitant NAC if they had impaired hepatic or renal function at baseline or developed hepatotoxicity during treatment. The study aim was to retrospectively explore trabectedin administration in terms of number of cycles, mean dose, and dose intensity (DI) in patients who received NAC as compared with those who did not. Secondary end points were progression-free survival (PFS) and overall survival (OS). RESULTS: A total number of 18 patients were enrolled in this study. Nine received NAC and nine did not. The median number of administered trabectedin cycles, mean trabectedin dose/cycles, and median DI was comparable in the two groups (p = 0.450, p = 0.534, and p = 0.450, respectively). The PFS and OS curves overlapped. CONCLUSION: This explorative study suggests that NAC can have a hepatoprotective activity in patients receiving trabectedin allowing to maintain an adequate dose intensity and continuative administration in patients with impaired liver and renal function or developing treatment-induced hepatotoxicity. A prospective randomized trial is warranted.

Humoral response to anti SARS-CoV2 vaccination at one and seven months is not different in shift workers and non-shift workers.

Since previous studies, mostly performed in healthy adults, show that sleep restriction around time of vaccination impairs antibody response and shift work affects sleep, aim of the study was to test the hypothesis that the antibody response to vaccination is impaired in shift workers, when compared to non-shift workers. Employees (n = 445; mean age 44 ± 11 years; 35 % men) of the Centro Cardiologico Monzino, IRCCS (Milan, Italy) were vaccinated against SARS-CoV2 in February 2021 with an mRNA-based vaccine. Antibody titers were assayed 1 and 7 months later. Differences between groups were assessed using ANOVA, after log-transformation of variables with right-skewed distribution. We report that the antibody titer was significantly higher in shift workers (33 % of employees) compared to non-shift workers at first assay [median (IQR): 2495 (1700; 4665) vs 2060 (1619; 2970) BAU/mL, p = 0.0123], as well as at the second one, and that this difference was abolished after adjustment for previous development of symptomatic COVID-19. Results were not affected by age or sex at birth. These results show that shift workers were able to mount an unimpaired antibody response to vaccination. Since vaccinations were performed during the pandemic urgency, our retrospective study has several limitations, nevertheless it underlines the need for large prospective, controlled studies on the effects of acute and chronic sleep restriction on response to vaccination in the general population and on the impact of shift work on immune response.

Clinical presentation and outcome of patients with enteric-type adenocarcinoma of the lung: A pooled analysis of published cases.

Enteric-type adenocarcinoma of the lung (lung-ETAC, former pulmonary enteric adenocarcinoma, PEAC) is a rare subtype of non-small cell lung cancer (NSCLC), which shares morphological and immunohistochemical features with lung and colorectal adenocarcinoma. Few data are available on patient prognosis, possible prognostic factors and systemic approach to metastatic disease. We performed a pooled analysis and a systematic review of published lung-ETAC, along with an additional case description. Thirty-one eligible publications were identified, providing data from 126 patients. In the 127 patients overall analyzed, median overall survival (OS) was 56.0 (range 36.7-75.3) months in early-stage patients and 14.0 (range 4.5-23.5) months in those with advanced/metastatic disease. Median disease-free survival (DFS) after radical surgery was 24 (range 22.6-35.1) months. Smoking status (HR 4.304, 95% CI: 1.261-14.693, p = 0.020) and node involvement (HR 1.853, 95% CI: 1.179-2.911, p = 0.007) were the negative independent prognostic factors at multivariate analysis. As regards systemic therapies for advanced cases, no firm conclusions were drawn about the efficacy of lung cancer-oriented chemotherapy regimens as opposed to colon cancer-oriented ones. Molecular analysis of lung-ETAC revealed a relatively high mutational rate, with alterations in several druggable molecular pathways, KRAS and NRAS (31%) were the most frequently mutated oncogenes, followed by ROS1 (15%), RET (13%), BRAF (11%), EGFR (8%) and ALK (6%). Moreover, 3 (15%) out of 20 cases showed DNA mismatch repair deficiency (dMMR). In conclusion, advanced lung-ETAC patients appeared to have a better prognosis compared to other subtypes of NSCLC. Moreover, the mutational rate and microsatellite instability found in lung-ETACs suggest that a significant proportion of these patients could benefit from target therapies and immunotherapy.

Time in therapeutic range is lower in women than in men and is not explained by differences in age or comorbidity.

BACKGROUND: Time in therapeutic range (TTR) measures the stability of the international normalized ratio in patients on vitamin K antagonists (VKA). Low values are associated with poor outcomes. Women were shown to have lower TTR than men, but the causes are poorly defined. It was suggested that women on VKA are older and more morbid than men, and this could affect the stability of anticoagulation. We aimed to identify variables that affect TTR differently in women and men. MATERIALS AND METHODS: This is a retrospective study in patients referred to a University hospital anticoagulant clinic. Age, sex, comorbidities, number of daily medications, indication and type of anticoagulant, weekly dosage and distribution, were derived from electronic records. Differences by sex and regression analysis to identify significant modulators of TTR were computed. RESULTS: 1182 women and 1281 men on VKA were studied. Women were older than men (81.5 yrs. ± 11.2 vs 78.4 yrs. ± 12.2), and had lower TTR (65% ± 20.3 vs 69% ± 19.8). Comorbidity was similar between sexes and negatively affected TTR in both. Mechanical valves as an indication to anticoagulation and acenocoumarol as an anticoagulant as opposed to warfarin had a strong negative influence on TTR, while age increased TTR. Being a man rather than a woman afforded more than three TTR points. Number of medications and average anticoagulant dose were equal between sexes. DISCUSSION: Women have a lower TTR than men, on average below the safety threshold. They were indeed older, but age positively influenced TTR. Since women and men were equally comorbid, neither age nor disease explains differences in TTR. None of the other variables included in the study could explain the gender gap in TTR. Since women are at increased risk of cardioembolic stroke in atrial fibrillation, an effort at defining other causes for the observed differences, closer monitoring and switching to direct anticoagulants whenever possible is warranted.

Outcome of Patients With Metastatic Lung Neuroendocrine Tumors Submitted to First Line Monotherapy With Somatostatin Analogs.

Objective: Antiproliferative activity of somatostatin analogs (SSAs) has been demonstrated in digestive neuroendocrine tumors (NETs), but few data have been published in patients with pulmonary NETs. We therefore conducted a retrospective study to provide additional data on the outcome of patients with metastatic lung NETs submitted to front line SSAs. Research Design and Methods: Patients with metastatic lung NET treated with first line SSA-monotherapy (octreotide or lanreotide) in two different reference Institutions were reviewed. Outcome measures were progression-free survival (PFS) overall survival (OS), overall response rate and safety. We also explored prognostic factors associated with PFS. Methods: The outcome of consecutive patients (pts) with metastatic lung NETs, who underwent first-line treatment with SSAs, recruited from 2014 on 2019 in two Italian reference Institutions, was retrospectively evaluated. Results: Thirty-one patients entered the study: 14 (45.2%) with typical and 17 (54.8%) atypical carcinoid. Six patients (19.4%) had a carcinoid syndrome. 60.0% of patients had Ki-67 ≤ 10%. Two (6.5%) patients obtained a partial response, 24 (77.4%) disease stabilization while 5 (16.1%) had progressive disease. Median progression free survival (PFS) was 28.6 months, median overall survival (OS) was not attained. Ki-67 ≤ 10%, typical carcinoid histotype and non-functioning disease, were associated with a non-significant PFS prolongation. PFS in patients with atypical carcinoids and in those with Ki-67 >10% was greater than 19 months. Conclusions: The long PFS and OS obtained in this case series suggest that SSAs could be effective as first line approach in the management of patients with progressive, metastatic pulmonary NET.

Accurate Triage of Oncological Patients for Safely Continuing Cancer Therapy During the SARS-CoV-2 Pandemic.

OBJECTIVE: To evaluate the efficacy of clinical triage of oncological patients for safe continuation of cancer therapy implemented during the first SARS-CoV-2 outbreak. METHODS: Between 25 February and 21 April 2020, patients attending the Medical Oncology Unit, Spedali Civili Hospital, Brescia (Italy) for cancer therapy underwent triage to identify those with no signs and symptoms suspicious for SARS-CoV-2 infection in which antineoplastic treatment could be continued as scheduled. Triage questions investigated common symptoms (e.g., fever, cough, dyspnea, anosmia, dysgeusia, headache, nasal congestion, conjunctival congestion, sore throat, diarrhea, nausea and vomiting); body temperature and pulse oximetry were also recorded. All patients were followed-up for overt SARS-CoV-2 through to 18th May 2020. RESULTS: Overall, 1180 patients (median age 65 years) underwent triage during the study period. The most frequent primary malignances were breast (32%), gastrointestinal (18%), and lung (16.5%) cancer. Thirty-one (2.5%) presented with clinically evident SARS-CoV-2 infection and tested positive on nasopharyngeal swab testing and/or radiological imaging. Triage identified 69 (6%) grey zone patients with symptoms suspicious for SARS-CoV-2; 5 (7.2%) subsequently developed symptomatic disease. Neither the symptomatic nor the grey zone patients received their scheduled treatment; instead, they were referred for hospitalization or home quarantine. CONCLUSION: Triage of oncological patients at our Unit provided for safe continuation of scheduled cancer treatment in 91.5% of patients during the initial SARS-CoV-2 outbreak.

Maintenance versus discontinuation of androgen deprivation therapy during continuous or intermittent docetaxel administration in castration-resistant prostate cancer patients: A multicentre, randomised Phase III study by the Piemonte Oncology Network.

BACKGROUND: This study was designed to demonstrate the non-inferiority (NI) in overall survival (OS) of suspension of androgen deprivation therapy (ADT) versus maintenance and intermittent versus continuous docetaxel administration in metastatic castration-resistant prostate cancer (mCRPC) patients. PATIENTS AND METHODS: mCRPC patients were randomised to first-line docetaxel with maintenance or suspension of ADT. Patients attaining a prostate-specific antigen (PSA) response after four chemotherapy cycles underwent second randomisation to receive continuous or intermittent docetaxel therapy. Six hundred patients were to be randomised to achieve 80% statistical power to demonstrate an NI hazard ratio (HR) of 1.25 of interruption versus maintenance of ADT. RESULTS: The trial was prematurely closed when 198 participants were randomised. OS was similar in patients who continued (N = 96) versus those who interrupted (n = 102) ADT during docetaxel therapy (HR 0.98, 95% confidence interval [CI] 0.72-1.33] and those on a continuous (N = 35) versus an intermittent (N = 42) docetaxel schedule (HR 0.86, 95% CI 0.55-1.43). No difference in radiological progression-free survival, PSA response, or toxicity was observed between the study arms. The actual NI hazard margins of OS in Arms A and B patients were 1.33 and 1.43, respectively. CONCLUSIONS: This trial enrolled one-third of the planned patients; this main weakness dramatically limits the interpretation of the results. ADT discontinuation and switching to an intermittent schedule did not seem to affect docetaxel efficacy. The absence of testosterone recovery in the majority of patients could have been a contributory factor. In men with mCRPC, ADT discontinuation should only be done with regular biochemical and clinical monitoring, with the option of quickly restarting ADT at disease progression.

Interleukin-1 inhibits putative cholinergic neurons in vitro and REM sleep when microinjected into the rat laterodorsal tegmental nucleus.

STUDY OBJECTIVES: REM sleep is suppressed during infection, an effect mimicked by the administration of cytokines such as interleukin-1 (IL-1). In spite of this observation, brain sites and neurochemical systems mediating IL-1-induced suppression of REM sleep have not been identified. Cholinergic neurons in the brainstem laterodorsal tegmental nucleus (LDT) are part of the neuronal circuitry responsible for REM sleep generation. Since IL-1 inhibits acetylcholine synthesis and release, the aim of this study was to test the two different, but related hypotheses. We hypothesized that IL-1 inhibits LDT cholinergic neurons, and that, as a result of this inhibition, IL-1 suppresses REM sleep. DESIGN, MEASUREMENT, AND RESULTS: To test these hypotheses, the electrophysiological activity of putative cholinergic LDT neurons was recorded in a rat brainstem slice preparation. Interleukin-1 significantly inhibited the firing rate of 76% of recorded putative cholinergic LDT neurons and reduced the amplitude of glutamatergic evoked potentials in 60% of recorded neurons. When IL-1 (1 ng) was microinjected into the LDT of freely behaving rats, REM sleep was reduced by about 50% (from 12.7% +/- 1.5% of recording time [after vehicle] to 6.1% +/- 1.4% following IL-1 administration) during post-injection hours 3-4. CONCLUSIONS: Results of this study support the hypothesis that IL-1 can suppress REM sleep by acting at the level of the LDT nucleus. Furthermore this effect may result from the inhibition of evoked glutamatergic responses and of spontaneous firing of putative cholinergic LDT neurons.

Bone metastases from head and neck malignancies: Prognostic factors and skeletal-related events.

BACKGROUND: We conducted a multicenter retrospective analysis to describe the characteristics, frequency of skeletal-related events (SREs), and prognosis of head and neck cancer (HNC) in patients with bone metastases (BM). PATIENTS AND METHODS: The data of 192 HNC patients with BMs were collected. Analyses were conducted separately in 64 nasopharyngeal cancer (NPC) patients and in 128 non-NPC patients. RESULTS: SREs occurred in 34 (27%) non-NPC and in 6 (9%) NPC patients, respectively. Median overall survival (OS) was 25 and 6 months in NPC and non-NPC patients, respectively. Locoregional recurrence (hazard ratio [HR] 2.33, 95% confidence interval (CI) 1.1-4.93), synchronous BM (HR 0.25, 95% CI 0.59-0.71) and bone-directed therapies (BDT) (HR 0.26, 95% CI 0.10-0.68) were independent prognostic factors for OS in NPC patients. Combined bone radiotherapy (RT) and BDT in NPC patients obtained longer survival (38 months) than either therapy alone (25 months) or neither of these therapies (8 months). CONCLUSIONS: Patients with BMs from non-NPC have a poor prognosis and are at high risk of SREs. NPC patients with BMs are at relatively low risk of SREs. BDT may potentially improve survival, particularly when combined with bone RT. This last finding deserves prospective confirmation.

Mutant prion protein expression causes motor and memory deficits and abnormal sleep patterns in a transgenic mouse model.

A familial form of Creutzfeldt-Jakob disease (CJD) is linked to the D178N/V129 prion protein (PrP) mutation. Tg(CJD) mice expressing the mouse homolog of this mutant PrP synthesize a misfolded form of the mutant protein, which is aggregated and protease resistant. These mice develop clinical and pathological features reminiscent of CJD, including motor dysfunction, memory impairment, cerebral PrP deposition, and gliosis. Tg(CJD) mice also display electroencephalographic abnormalities and severe alterations of sleep-wake patterns strikingly similar to those seen in a human patient carrying the D178N/V129 mutation. Neurons in these mice show swelling of the endoplasmic reticulum (ER) with intracellular retention of mutant PrP, suggesting that ER dysfunction could contribute to the pathology. These results establish a transgenic animal model of a genetic prion disease recapitulating cognitive, motor, and neurophysiological abnormalities of the human disorder. Tg(CJD) mice have the potential for giving greater insight into the spectrum of neuronal dysfunction in prion diseases.

Inhibition of caspase-1 in rat brain reduces spontaneous nonrapid eye movement sleep and nonrapid eye movement sleep enhancement induced by lipopolysaccharide.

Evidence suggests that IL-1beta is involved in promoting physiological nonrapid eye movement (NREM) sleep. IL-1beta has also been proposed to mediate NREM sleep enhancement induced by bacteria or their components. Mature and biologically active IL-1beta is cleaved from an inactive precursor by a cysteinyl aspartate-specific protease (caspase)-1. This study aimed to test the hypothesis that inhibition in brain of the cleavage of biologically active IL-1beta will reduce in rats both spontaneous NREM sleep and NREM sleep enhancement induced by the peripheral administration of components of the bacterial cell wall. To test this hypothesis, rats were intracerebroventricularly administered the caspase-1 inhibitor Ac-Tyr-Val-Ala-Asp chloromethyl ketone (YVAD; 3, 30, 300, and 1,500 ng) or were pretreated intracerebroventricularly with YVAD (300 ng) and then intraperitoneally injected with the gram-negative bacterial cell wall component LPS (250 microg/kg). Subsequent sleep-wake behavior was determined by standard polygraphic recordings. YVAD administration at the beginning of the light phase of the light-dark cycle significantly reduced time spontaneously spent in NREM sleep during the first 12 postinjection hours. YVAD pretreatment also completely prevented NREM sleep enhancement induced by peripheral LPS administration at the beginning of the dark phase. These results, in agreement with previous evidence, support the involvement of brain IL-1beta in physiological promotion of NREM sleep and in mediating NREM sleep enhancement induced by peripheral immune challenge.

Antagonism of corticotropin-releasing hormone alters serotonergic-induced changes in brain temperature, but not sleep, of rats.

Serotonin is involved in many physiological processes, including the regulation of sleep and body temperature. Administration into rats of low doses (25, 50 mg/kg) of the 5-HT precursor l-5-hydroxytryptophan (5-HTP) at the beginning of the dark period of the 12:12-h light-dark cycle initially increases wakefulness. Higher doses (75, 100 mg/kg) increase nonrapid eye movement (NREM) sleep. The initial enhancement of wakefulness after low-dose 5-HTP administration may be a direct action of 5-HT in brain or due to 5-HT-induced activation of other arousal-promoting systems. One candidate arousal-promoting system is corticotropin-releasing hormone (CRH) and the hypothalamic-pituitary-adrenal axis. Serotonergic activation by 5-HTP at the beginning of the dark period also induces hypothermia. Because sleep and body temperature are influenced by circadian factors, one aim of this study was to determine responses to 5-HTP when administered at a different circadian time, the beginning of the light period. Results obtained show that all doses of 5-HTP (25-100 mg/kg) administered at light onset initially increase wakefulness; NREM sleep increases only after a long delay, during the subsequent dark period. Serotonergic activation by 5-HTP at light onset induces hypothermia, the time course of which is biphasic after higher doses (75, 100 mg/kg). Intracerebroventricular pretreatment with the CRH receptor antagonist alpha-helical CRH does not alter the impact of 5-HTP on sleep-wake behavior but potentiates the hypothermic response to 50 mg/kg 5-HTP. These data suggest that serotonergic activation by peripheral administration of 5-HTP may modulate sleep-wake behavior by mechanisms in addition to direct actions in brain and that circadian systems are important determinants of the impact of serotonergic activation on sleep and body temperature.

Interleukin-1beta enhances non-rapid eye movement sleep when microinjected into the dorsal raphe nucleus and inhibits serotonergic neurons in vitro.

Interleukin-1 (IL-1) and IL-1 receptors are constitutively expressed in normal brain. IL-1 increases non-rapid eye movements (NREM) sleep in several animal species, an effect mediated in part by interactions with the serotonergic system. The site(s) in brain at which interactions between IL-1 and the serotonergic system increase NREM sleep remain to be identified. The dorsal raphe (DRN) is the origin of the major ascending serotonergic pathways to the forebrain, and it contains IL-1 receptors. This study examined the hypothesis that IL-1 increases NREM sleep by acting at the level of the DRN. IL-1beta (0.25 and 0.5 ng) was microinjected into the DRN of freely behaving rats and subsequent effects on sleep-wake activity were determined. IL-1beta 0.5 ng increased NREM sleep during the first 2 h post-injection from 33.5 +/- 3.7% after vehicle microinjection to 42.9 +/- 3.0% of recording time. To determine the effects of IL-1beta on electrophysiological properties of DRN serotonergic neurons, intracellular recordings were performed in a guinea-pig brain stem slice preparation. In 26 of 32 physiologically and pharmacologically identified serotonergic neurons, IL-1beta superfusion (25 ng/mL) decreased spontaneous firing rates by 50%, from 1.6 +/- 0.2 Hz (before IL-1beta superfusion) to 0.8 +/- 0.2 Hz. This effect was reversible upon washout. These results show that IL-1beta increases NREM sleep when administered directly into the DRN. Serotonin enhances wakefulness and these novel data also suggest that IL-1beta-induced enhancement of NREM sleep could be due in part to the inhibition of DRN serotonergic neurons.