Portacaval anastomosis disrupts circadian locomotor activity and pineal melatonin rhythms in rats

Rest-activity rhythm disturbance in liver cirrhosis and association with cognitive impairment

Cognitive impairment and disturbed sleep-wake rhythms are disabling complications of liver cirrhosis, yet there is limited understanding of how they are related. We tested the hypothesis that alterations of sleep, rest-activity, and light exposure patterns are associated with worse cognition in cirrhosis. A total of 54 ambulatory adult patients with cirrhosis and 41 age-/gender-matched healthy controls wore wrist actigraphy for rest-activity and light measurements and completed Patient-Reported Outcomes Measurement Information System sleep instruments for self-reported sleep quality. We used standard nonparametric descriptors to characterize rest-activity and light patterns, and wake after sleep onset and sleep efficiency to assess objective sleep quality. The NIH Toolbox cognition battery was used for objective cognitive evaluation using T-scores from a demographically adjusted population reference. Spearman's correlation and multivariable models were used to explore associations between measures of cognition, sleep, rest-activity, and light. Cognition was significantly impaired in cirrhosis patients. Sleep quality was worse in cirrhosis patients by subjective and objective measures compared with controls. Cirrhosis patients exhibited fragmented and dampened rest-activity rhythms, lower daytime and higher nighttime light exposure compared with controls. Worse working memory and processing speed was associated with lower daytime activity level, higher rest-activity fragmentation, lower day-to-day stability, and greater nocturnal light exposure. No association was found between cognition and sleep quality. Rest-activity fragmentation and abnormal light exposure patterns are common in patients with liver disease and are associated with the severity of cognitive impairment. Further research is needed to investigate the effects of timed bright light and exercise intervention on cognitive function in patients with liver disease.

Sleep Disturbance Is Associated With the Presence of Portosystemic Collaterals in Patients With Compensated Cirrhosis

Disturbed sleep is common among patients with cirrhosis. The extent to which this is associated with the different stages of compensated cirrhosis is unknown. This study examines whether the presence of portosystemic collaterals, an indicator of clinically significant portal hypertension, is associated with sleep disturbance in compensated cirrhosis. We conducted a cross-sectional study among patients with compensated cirrhosis, comparing sleep characteristics, sleep quality, and excessive daytime sleepiness between 21 patients without and 21 patients with portosystemic collaterals. Patients were assessed with wrist actigraphy, Pittsburgh Sleep Quality Index, and the Epworth Sleepiness Scale. Collateral presence was determined by imaging and esophagogastroduodenoscopy. Differences in sleep characteristics were analyzed using t tests and computed effect sizes. Multivariable linear regression analysis was used to evaluate the association between collaterals and sleep disturbance while controlling for possible confounders. The group of patients with collaterals had greater beta-blocker and tobacco use, lower albumin, and higher international normalized ratio compared to the group without collaterals. Patients with collaterals had more sleep fragmentation (Cohen's d = -0.86), lower sleep efficiency (Cohen's d = 0.59), and lower total sleep time (Cohen's d = 0.75) than patients without collaterals. The presence of collaterals was independently associated with greater sleep fragmentation (P = 0.046) and greater daytime sleepiness (P = 0.030). Conclusion: Patients with compensated cirrhosis complicated by portosystemic collaterals experienced more sleep disturbance than those without collaterals.

Comprehensive Overview of Sleep Disorders in Patients with Chronic Liver Disease

The impact of sleep disorders (SDs) on patients with chronic liver diseases (CLD) is tremendous. SDs are frequently encountered among these patients and interfere with their quality of life. This review aims to present the data available so far about the prevalence, phenotypes, and proposed pathophysiological mechanisms of SDs in CLD. Moreover, we proposed to search the literature regarding the most reliable methods to assess SDs and the possible therapeutic options in patients with CLD. The main results of this review show that when it comes to prevalence, the percentages reported vary widely between studies performed among populations from the USA or Europe and those coming from Asian countries. Furthermore, it has been proven that SDs may also be present in the absence of neurocognitive disorders attributable to hepatic encephalopathy (HE), which contradicts traditional suppositions where SDs were considered part of the clinical scenario of HE. Currently, there are no specific recommendations or protocols to assess SDs in CLD patients and data about the therapeutic management are limited. Taking into consideration their impact, a protocol for diagnosing and managing SDs should be developed and included in the daily practice of hepatologists.

Serum melatonin in dogs with congenital portosystemic shunting, with and without hepatic encephalopathy

BACKGROUND

Melatonin is a hormone produced and secreted primarily by the pineal gland and mainly metabolised in the liver. Increased melatonin concentrations have been reported in human cirrhosis and hepatic encephalopathy (HE), a syndrome of neurological dysfunction. The pathogenesis of canine HE is incompletely understood. Melatonin has been hypothesised as a contributor to the development of HE. The aim of this study was to investigate whether serum melatonin concentrations are increased in canine congenital portosystemic shunting (cPSS), with and without HE.

METHODS

Medical records were retrospectively reviewed, for which archived (-80°C) serum samples were available. A canine competitive ELISA was used to measure melatonin in two cohorts: dogs with a final diagnosis of cPSS (n=23) with and without clinical signs of HE, and healthy dogs (n=15).

RESULTS

Melatonin concentrations were not significantly different (P=0.81) between healthy controls (median 27.2 pg/mL, range 19.8-161.5 pg/mL) and dogs with cPSS (median 25.7 pg/mL, range 18.5-244.9 pg/mL). Serum melatonin did not differ between cPSS patients with and without clinical signs of HE (P>0.99). No correlation was found between serum melatonin and blood ammonia (Spearman rank correlation coefficient, r_s =-0.41, P=0.08).

CONCLUSION

Serum melatonin is not increased in canine cPSS with and without HE. We found no evidence that altered melatonin metabolism plays a role in the pathogenesis of cPSS-associated HE.

Challenging Circadian Rhythm Disorder Cases

The complex interplay of the sleep and circadian systems, which are substantially differentially regulated, provides for plasticity that is expressed in health and disease. The classic circadian rhythm disorders are readily recognizable, but atypical forms can be identified by actigraphy and melatonin profilometry. Although the dim-light melatonin onset test maps the start of the biological night, 24-hour mapping can define the limits of the biological night, whereas other forms of strategic testing can identify conditions such as iatrogenic hypermelatoninemia. Routine testing in clinical practice can expand the range of identifiable circadian rhythm disorders.

Sleep disturbances in patients with liver cirrhosis: prevalence, impact, and management challenges

Sleep-wake disturbances are common in liver cirrhosis and associated with impaired quality of life. The most common abnormalities are insomnia (difficulties falling asleep and maintaining sleep, or unrefreshing sleep), excessive daytime sleepiness, and sleep-wake inversion (disturbances of circadian rhythmicity). The underlying pathophysiological mechanisms for sleep disturbances in cirrhosis are complex and may include disturbed metabolism of melatonin and glucose, alterations in thermoregulation, and altered ghrelin secretion profiles. Sleep-wake abnormalities are related to the presence of hepatic encephalopathy (HE) and improvement in sleep parameters can be observed when HE is properly managed. A few non-specific treatments for sleep-wake abnormalities have been tried with encouraging results for hydroxyzine and modafinil. However, due to the potential for medication toxicity in these disabled patients, further studies are needed to address the potential role of non-drug therapies in this population (eg, cognitive behavioral therapy, mindfulness, yoga) that have demonstrated usefulness in insomnia disorders.

Most Individuals With Advanced Cirrhosis Have Sleep Disturbances, Which Are Associated With Poor Quality of Life

BACKGROUND & AIMS

Sleep disturbances are common in patients with cirrhosis, but their determinants and effects on health-related quality of life are not well-understood. We investigated the prevalence of disturbed sleep in these patients, factors associated with sleep disruption, and effects on quality of life.

METHODS

We performed a prospective, cross-sectional study of 193 stable ambulatory patients with cirrhosis (154 with decompensated cirrhosis). Participants completed the Pittsburgh Sleep Quality Index (to assess sleep quality), the Chronic Liver Disease Questionnaire (CLDQ), and muscle cramp questionnaires and underwent neurocognitive testing. Actigraphy was performed in a subset of patients with normal and disturbed sleep. We collected serum samples from subjects with normal and disturbed sleep and performed non-targeted metabolomic analyses.

RESULTS

Of the study subjects, 157 (81%) had disturbed sleep, with Pittsburgh Sleep Quality Index scores >5. Disturbed sleep was associated with muscle cramps, daytime somnolence, and decreased quality of life on the basis of CLDQ scores. Factors independently associated with disturbed sleep in logistic regression analysis included hypoalbuminemia, opiate therapy, and muscle cramps. Disturbed sleep was independently associated with CLDQ score (correlation parameter, -36.6; 95% confidence interval, -24 to -49; P < .001) on linear regression. Disturbed sleep was associated with neurocognitive impairment and with significantly delayed bedtime and decreased total sleep time, measured by actigraphy. Disturbed sleep was associated with metabolome signatures of alterations to the intestinal microbiome and lipid, arginine, and urea cycle metabolism.

CONCLUSIONS

Most patients with advanced cirrhosis (81%) have disturbed sleep. This has negative effects on quality of life and is associated with disruptions of several metabolic pathways, including metabolism by the intestinal microbiota.

Prevalence and predictors of sleep disturbance among liver diseases in long-term transplant survivors

BACKGROUND

Patients with cirrhosis are known to experience sleep disturbance, which negatively impacts health-related quality of life.

OBJECTIVE

To assess the prevalence and predictors of sleep disturbance before and after liver transplantation (LT).

METHODS

Both pre- and post-LT patients were administered the Basic Nordic Sleep Questionnaire. The primary outcome was overall sleep satisfaction; the secondary outcomes were sleep latency and sleep duration.

RESULTS

Eighty-three patients participated pre-LT and 273 post-LT. Overall, participants having completed both pre- and post-LT questionnaires reported satisfactory sleep 61% of the time before LT and 65% of the time after LT. However, on review of all questionnaires, patients with alcoholic liver disease (ETOH) experienced dramatically less sleep disturbance (OR 0.13 [95% CI 0.03 to 0.60]) post-LT, whereas those with hepatitis C remained without improvement (OR 0.90 [95% CI [0.38 to 2.15]). On logistic regression, patients with ETOH had statistically less sleep satisfaction pre-LT (OR 5.8 [95% CI 1.0 to 40.5]) and significantly better sleep satisfaction post-LT (OR 0.50 [95% CI 0.20 to 1.00]) compared with those with hepatitis C. In addition, both ETOH and other conditions had significantly better sleep latency than hepatitis C patients.

CONCLUSIONS

Sleep parameters for patients who undergo LT for hepatitis C do not improve following LT as much as they do in patients transplanted for ETOH. Following LT, patients transplanted for ETOH are significantly more satisfied with their sleep than those transplanted for hepatitis C. Physicians should address and manage sleep quality after LT, so as to ultimately improve quality of life.

Extrapineal melatonin: sources, regulation, and potential functions

Endogenous melatonin is synthesized from tryptophan via 5-hydroxytryptamine. It is considered an indoleamine from a biochemical point of view because the melatonin molecule contains a substituted indolic ring with an amino group. The circadian production of melatonin by the pineal gland explains its chronobiotic influence on organismal activity, including the endocrine and non-endocrine rhythms. Other functions of melatonin, including its antioxidant and anti-inflammatory properties, its genomic effects, and its capacity to modulate mitochondrial homeostasis, are linked to the redox status of cells and tissues. With the aid of specific melatonin antibodies, the presence of melatonin has been detected in multiple extrapineal tissues including the brain, retina, lens, cochlea, Harderian gland, airway epithelium, skin, gastrointestinal tract, liver, kidney, thyroid, pancreas, thymus, spleen, immune system cells, carotid body, reproductive tract, and endothelial cells. In most of these tissues, the melatonin-synthesizing enzymes have been identified. Melatonin is present in essentially all biological fluids including cerebrospinal fluid, saliva, bile, synovial fluid, amniotic fluid, and breast milk. In several of these fluids, melatonin concentrations exceed those in the blood. The importance of the continual availability of melatonin at the cellular level is important for its physiological regulation of cell homeostasis, and may be relevant to its therapeutic applications. Because of this, it is essential to compile information related to its peripheral production and regulation of this ubiquitously acting indoleamine. Thus, this review emphasizes the presence of melatonin in extrapineal organs, tissues, and fluids of mammals including humans.

Melatonin secretion and metabolism in patients with hepatic encephalopathy

BACKGROUND AND AIM

The rhythm of melatonin secretion and its blood level changes in cirrhotic patients, but the causes of these alterations have not been sufficiently appreciated. The aim of study was to estimate the dependence between melatonin secretion and metabolism and the severity of hepatic encephalopathy.

METHODS

The study included 75 alcoholic cirrhotic patients (A, B, C) with hepatic insufficiency and 25 healthy subjects (group K). Three groups of patients were identified, 25 patients each, with grade 1, 2, and 3 hepatic encephalopathy according to West-Haven Scale. Immunoenzymatic method was used to measure serum melatonin (at 02:00 h and 09:00 h) level and 6-sulfatoxymelatonin (6-HMS) excretion in the urine (during night and day).

RESULTS

Nocturnal serum melatonin levels (pg/mL) in groups were: K-57.1 ± 11.4, A-38.5 ± 11.2, B-53.4 ± 17.9, C-79.5 ± 27.9 (P < 0.01); whereas diurnal levels were: K-10.9 ± 3.5, A-33.5 ± 12.0, B-53.8 ± 23.1, C-98.5 ± 34.6 (P < 0.01). Similar differences were found in the evaluation of 6-HMS excretion (μg/9 h) in urine at night: group K-23.4 ± 14.4, A-16.6 ± 5.4, B-14.3 ± 6.2 (P < 0.01), C-3.3 ± 1.5 (P < 0.001). Diurnal 6-HMS excretion (μg/15 h) was lower only in group C and it was respectively: K-6.9 ± 3.4, A-7.1 ± 1.7, B-7.6 ± 1.7, C-4.3 ± 2.2 (P < 0.001). Serum ammonia concentrations (μg/dL) were: group K-30.4 ± 8.9, A-51.8 ± 25.4 (P < 0.05), B-73.0 ± 29.8 (P < 0.001), C-107.5 ± 34.8 (P < 0.001). No correlation between melatonin and ammonia levels in all groups was found.

CONCLUSIONS

The elevated melatonin blood levels both at night and day may account for some of the clinical manifestations of hepatic encephalopathy (daytime sleepiness, fatigue).

Survey on lower urinary tract symptoms and sleep disorders in patients treated at urology departments

OBJECTIVES

This study examined the association between sleep disorders and lower urinary tract symptoms in patients who had visited urology departments.

METHODS

This was an independent cross-sectional, observational study. Outpatients who had visited the urology departments at the Kinki University School of Medicine or the Sakai Hospital, Kinki University School of Medicine, between August 2011 and January 2012 were assessed using the Athens Insomnia Scale and the International Prostate Symptom Score.

RESULTS

In total, 1174 patients (mean age, 65.7 ± 13.7 years), with 895 men (67.1 ± 13.2 years old) and 279 women (61.4 ± 14.6 years old), were included in the study. Approximately half of these patients were suspected of having a sleep disorder. With regard to the International Prostate Symptom Score subscores, a significant increase in the risk for suspected sleep disorders was observed among patients with a post-micturition symptom (the feeling of incomplete emptying) subscore of ≥1 (a 2.3-fold increase), a storage symptom (daytime frequency + urgency + nocturia) subscore of ≥5 (a 2.7-fold increase), a voiding symptom (intermittency + slow stream + hesitancy) subscore of ≥2 (a 2.6-fold increase), and a nocturia subscore of ≥2 (a 1.9-fold increase).

CONCLUSION

The results demonstrated that the risk factors for sleep disorders could also include voiding, post-micturition, and storage symptoms, in addition to nocturia.

Melatonin levels in serum and ascitic fluid of patients with hepatic encephalopathy

Cirrhotic patients exhibit disturbed melatonin homeostasis, which may lead to sleep disturbances, but an influence on the hepatic encephalopathy has not been elucidated. Aim. In the present study, the association of melatonin levels in serum and ascitic fluid and ammonia concentration related to the intensity of hepatic encephalopathy (HE) was investigated. Material and Methods. The study included 90 alcoholic patients with hepatic encephalopathy and 30 healthy volunteers (C). Patients were divided in three groups according to 0–4 West-Haven Score: HE₁ (n = 28), HE₂ (n = 30), and HE₃ (n = 32). Melatonin was measured by radioimmune assay. Results. In fasting patients with hepatic encephalopathy we noted higher melatonin serum levels [pg/mL] than in healthy subjects groups: C—11.3 ± 3.9, HE₁ – 34.3 ± 12.2 (P < 0.01), HE₂—54.8 ± 23.9, and HE₃—119.8 ± 96.4 (P < 0.001). No correlation between melatonin and ammonia levels was found. Melatonin was detected in ascetic fluid in 24 patients of group HE₂ and 27 patients of group HE₂ of hepatic encephalopathy. Conclusions. Our results suggest that high blood levels of melatonin in cirrhotic liver patients may account for some of the clinical manifestations of hepatic encephalopathy, for example, daytime sleepiness, fatigue.

Progressive reduction of sleep time and quality in rats with hepatic encephalopathy caused by portacaval shunts

Patients with liver cirrhosis show sleep disturbances. Insight into their relationship with hepatic encephalopathy (HE) can be obtained using animal models of HE. The aims of this work were to assess (1) whether rats with portacaval shunts (PCS), a model of HE, show alterations in sleep and if they are similar to those in patients with HE; (2) Whether hyperammonemia plays a role in these sleep alterations; and (3) the time course of sleep alterations in these animal models. Rats were subjected to PCS to induce HE. Another group of rats was fed an ammonium-containing diet to induce hyperammonemia. Polysomnographic recordings were acquired for 24 h and sleep architecture was analyzed in control, PCS, and hyperammonemic rats at 4, 7, and 11 weeks after surgery or diet, respectively. PCS rats show a significant reduction in rapid eye movement (REM) and non-rapid eye movement (NREM) sleep time and increased sleep fragmentation, whereas reduced sleep occurs at 4 weeks and worsens at 7 and 11 weeks, sleep fragmentation appears at 7 weeks and worsens at 11 weeks. Hyperammonemic rats show decreased REM sleep, starting at 7 weeks and worsening at 11 weeks, with no changes in NREM sleep or sleep fragmentation. Therefore, PCS rats are a good model to study sleep alterations in HE, their mechanisms, and potential treatment. Mild hyperammonemia mainly impacts mechanisms involved in REM generation and/or maintenance but does not seem to be involved in sleep fragmentation.

Modification of sleep architecture in an animal model of experimental cirrhosis

AIM: To analyze the polygraphic sleep patterns during cirrhosis progression in a rat model by repeated CCl₄ administration.

METHODS: Male Wistar rats received three weekly injections of CCl₄ for 11 wk, and were analyzed before and during the induction of cirrhosis. Rats were implanted with electrodes to record their sleep patterns. Polygraph recordings were made weekly over 11 wk for 8 h, during the light period. After a basal recording, rats received three weekly injections of CCl₄. Histological confirmation of cirrhosis was performed after 11 wk.

RESULTS: The results showed a progressive decrease in total wake time that reached statistical significance from the second week of treatment. In addition, there was an increase in total time of slow wave sleep (SWS) II and rapid eye movement sleep (REM sleep) in most of the 11 wk. SWS I showed no significant variations. During the final weeks, a significant increase in REM sleep frequency was also observed. Histological analyses of the livers showed unequivocal signs of cirrhosis.

CONCLUSION: These data suggest that hepatic failure produced by CCl₄ administration is capable of modifying the sleep pattern even after only a few doses.

Indomethacin improves locomotor deficit and reduces brain concentrations of neuroinhibitory steroids in rats following portacaval anastomosis

Hepatic encephalopathy (HE) is a neuropsychiatric complication of both acute and chronic liver failure characterized by progressive neuronal inhibition. Some neurosteroids are potent positive allosteric modulators of the gamma-aminobutyric acid (GABA)-A receptor complex, and 'increased GABAergic tone' has been proposed to explain the neuroinhibition characteristics of HE. Brain levels of the neurosteroids pregnenolone, allopregnanolone and tetrahydrodesoxycorticosterone (THDOC) and the functional status of the GABA-A receptor complex were assessed in rats following portacaval anastomosis (PCA). Effects of indomethacin, an inhibitor of the 3alpha-hydroxysteroid dehydrogenase enzyme involved in neurosteroid synthesis, on PCA rat locomotor activity and brain neurosteroid levels were also assessed. Significant increases of the neurosteroid pregnenolone (2.6-fold), allopregnanolone (1.7-fold) and THDOC (4.7-fold) were observed in brains of PCA rats. Brain levels of these neurosteroids were in the nanomolar range, sufficient to exert positive allosteric modulatory effects at the GABA-A receptor. Indomethacin (0.1-5 mg kg(-1)) ameliorated dose-dependently the locomotor deficit of PCA rats and concomitantly normalized brain levels of allopregnanolone and THDOC. Increased brain levels of neurosteroids with positive allosteric modulatory actions at the neuronal GABA-A receptor offer a cogent explanation for the notion of 'increased GABAergic tone' in HE. Pharmacological approaches using agents that either reduce neurosteroid synthesis or modulate the neurosteroid site on GABA-A receptor could offer new therapeutic tools for the management and treatment of HE.

Sustained citalopram treatment in experimental hepatic encephalopathy: effects on entrainment to the light-dark cycle and melatonin

Patients with chronic hepatic encephalopathy often display altered diurnal rhythm as well as other affective disturbances which motivate treatment with antidepressants. We investigated the effects of sustained treatment with citalopram (10 mg/kg daily, 10 days) on 24-hr behavioural open-field activities in portacaval-shunted (PCS) rats and sham-operated control rats. In addition, the daytime and nighttime serum melatonin levels, as well as the serum concentrations of the enantiomers of citalopram and its metabolites, were analyzed. Untreated PCS rats showed reduced locomotor and rearing activities during nighttime. Citalopram treatment resulted in elevated behavioural activity in the PCS rats during night, indicative of an improved entrainment to the light-dark cycle, whereas no behavioural effect could be observed in sham rats. Higher melatonin levels in both PCS and sham rats were observed during nighttime compared with daytime, but the untreated PCS rats also showed higher daytime melatonin level than the corresponding sham group. Citalopram treatment seemed not to have any major effect on the melatonin levels. Higher serum levels of both citalopram and metabolites were observed in PCS rats as compared to sham rats. An altered ratio between the S- and R-enantiomers could also be observed in the PCS rats. In conclusion, the present data support the contention of a disturbed diurnal rhythm, and that the melatonin activity may be altered, in chronic hepatic encephalopathy. The citalopram treatment resulted in similar behavioural performances and daytime serum melatonin levels in PCS rats and controls, although pharmacokinetic differences were present between the groups.

Sleep apnoea syndrome and early stage cirrhosis: a pilot study

OBJECTIVES

Hepatic encephalopathy in patients with end-stage liver cirrhosis is associated with alterations in sleep patterns. Cirrhosis may also affect pulmonary function and it might be involved in the development of obstructive sleep apnoea syndrome (OSAS) in patients with ascites. We carried out a study to evaluate the presence of OSAS in cirrhotic patients without evidence of ascites (early stage cirrhosis).

METHODS

We investigated 20 patients with Child A or B cirrhosis (19 and one, respectively) and 10 non-cirrhotic patients with chronic viral hepatitis (disease control group). All subjects were interviewed and underwent a thorough physical examination, a full polysomnographic study and a pulmonary function testing by spirometry. Serum samples were also obtained in order to determine the liver function tests.

RESULTS

The presence of OSAS and inverted sleep patterns was similar in cirrhotic patients and disease controls. However, significant correlations were revealed between age and hypopnoeas per hour of sleep; age and the Apneas/Hypopneas Index (AHI); age and FEV1/FVC; gamma-glutamyl transpeptidase and FEV1/FVC; and total bilirubin and total sleep time.

CONCLUSIONS

Early stage cirrhosis is not associated with sleep disorders and OSAS. However, total bilirubin levels might be a useful laboratory marker for early assessment of disturbance in sleep patterns and therefore of subclinical hepatic encephalopathy in Child A cirrhosis.

Rats made cirrhotic by chronic CCl4 treatment still exhibit anticipatory activity to a restricted feeding schedule

Food entrainment of clock genes in the liver suggests that this organ may underlie a food entrained oscillator (FEO), which manifests under restricted feeding schedule (RFS). In order to test the importance of a functional liver for the expression of FEO, chronic CCl4-treated cirrhotic rats and oil-treated controls were entrained to RFS and drinking behavior was continuously monitored. After 20 d of free-running conditions, food access was restricted to 2 h, followed by a refeeding-fasting protocol to test persistence of anticipatory drinking. Present data show no differences between groups for the onset and intensity of anticipation during RFS. After RFS, however, cirrhotic rats exhibited a significantly longer free-running period and a delay and lower intensity of the persistence of activity under fasting conditions. Histology confirmed injury of the liver chronically treated with CCl4. Present data indicate that a dysfunctional liver due to chronic CCl4 does not prevent animals from exhibiting anticipatory activity but may promote metabolic derangement of the clock mechanisms of the suprachiasmatic nucleus and the FEO.

Cytochrome oxidase activity of the suprachiasmatic nucleus and pineal gland in rats with portacaval shunt

Rhythmic behavioral and biochemical changes have been observed in both human and animal models with hepatic insufficiency. The basis of all these alterations is the principal endogenous pacemaker, the suprachiasmatic nucleus. The aim of this work, therefore, is to determine cytochrome c oxidase activity, a marker of neuronal activity and oxidative metabolism, in this nucleus in rats with portacaval shunt. In order to do this, this enzyme was histochemically marked and quantified by computer-assisted optical densitometry. Results show a reduced cytochrome oxidase activity in the suprachiasmatic nucleus in animals with portacaval shunts and, inversely, an increase in oxidative metabolism in the pineal gland, another circadian structure. However, the activity measured in a noncircadian brain structure, the hippocampus, which served as a control, showed no changes with surgery. Additionally, locomotor activity was assessed by actimeters and revealed a clearly reduced activity in animals with portacaval shunt. We conclude that the suprachiasmatic nucleus is possibly involved in the rhythmic changes associated with hepatic insufficiency.

Circadian variation in portal pressure: appropriate use of non-selective beta blockers in the prevention of variceal bleed

The circadian variation in some biologic functions may have clinical, fiscal and therapeutic implications. The authors discuss circadian variation in portal pressure in cirrhotic patients and nocturnal occurrence of bleeding from varices in these patients. The pathogenesis of the diurnal variation in portal pressure is presented. The authors submit the hypothesis that an optimal dosing regimen for non-selective beta blocker therapy in the prevention of variceal bleed must include an evening dose of beta blocker medication. In studies reporting comparative efficacy of beta blocker therapy with other modalities in the prevention of variceal bleeding, the optimal dosing schedule for beta blocker therapy must be emphasized.

Dynamic and kinetic effects of chronic citalopram treatment in experimental hepatic encephalopathy

Chronic hepatic encephalopathy (HE) is a neuropsychiatric syndrome that arises in liver-impaired subjects. Patients with HE display various neuropsychiatric symptoms including affective disturbances and may therefore likely receive treatment with novel thymoleptics like citalopram (CIT). The simultaneous pharmacokinetic and pharmacodynamic outcome of the commonly used serotonin-selective thymoleptic drugs in liver-impaired subjects with pending chronic HE is far from understood today. We therefore investigated the effects of chronic, body-weight-adjusted (10 mg x kg(-1) x day(-1)), treatment with CIT in rats with and without portacaval shunts (PCS). Open-field activity was monitored. The 5-HT, 5-HIAA, noradrenaline (NA), and dopamine (DA) output were assessed in the frontal neocortex. The racemic levels of CIT and its metabolites DCIT and DDCIT, including the S- and R-enantiomers, were determined in serum, brain parenchyma, and extracellular fluid. The rats with PCS showed higher (2-3-fold) levels of CIT than rats undergoing a sham treatment with CIT in all compartments investigated. The PCS rats also showed elevated levels of DCIT and DDCIT. No major differences in the S/R ratios between PCS rats and control rats could be detected. The CIT treatment resulted in neocortical output differences between PCS rats and control rats mainly within the 5-HT and DA systems but not within the NA system. For the 5-HT system, this change was further evidenced by outspoken elevation in 5-HT output after KCI-depolarizing challenges. Moreover, the CIT treatment to PCS rats was shown to "normalize" the metabolic turnover of 5-HT, measured as a profound lowering of a basal elevation in the 5-HIAA levels. The CIT treatment resulted in an increased or "normalized" behavioral activity in the PCS group. Therefore, a dose-equal chronic treatment with CIT in PCS rats produced pharmacokinetic and pharmacodynamic changes not observed in control rats. The results further support the contention of an altered 5-HT neurotransmission prevailing in the chronic HE condition. However, the tentatively beneficial behavioral response also seen following chronic CIT treatment to PCS rats in this study has to be viewed in relation to both the pharmacokinetic and pharmacodynamic changes observed.

Brain tryptophan/serotonin perturbations in metabolic encephalopathy and the hazards involved in the use of psychoactive drugs

Several combined pathogenetic factors such as hyperammonemia, different brain tryptophan metabolic disturbances and serotonin physiological/pharmacological alterations not yet defined in all details, will often give rise to the clinical neuropsychiatric condition known as hepatic encephalopathy (HE). Indeed, to this the probable exposure to novel potent CNS-monoamine acting drugs today may put such patients at certain risk for other pharmacodynamic (PD) responses than usually are expected from these "safe" drugs. Moreover, with a compromised liver function in HE, also pharmacokinetic (PK) features for the drugs are likely changed in these patients. Thus, the ultimate clinical outcome by this probable but unknown PD/PK-deviation for such psychoactive drugs when given to HE-patients needs further clarification. Accordingly, delineation of both PD- and PK-effects in experimental HE should shed light on this issue of relevance for monoamine-active drug safety as well as on some further details in the complex tryptophan/monoamine-related pathophysiology that comes into play in HE.

Effects of the histamine H(1) receptor blocker, pyrilamine, on spontaneous locomotor activity of rats with long-term portacaval anastomosis

To find out whether the changes in the brain histaminergic system are involved in the pathophysiology of portal-systemic encephalopathy, we examined the effects of histamine H(1) receptor blockade on spontaneous locomotor activity, feeding, and circadian rhythmicity in rats with portacaval anastomosis (PCA). Pyrilamine, an H(1) receptor blocker (15 mg/kg/day), was delivered with osmotic minipumps. Spontaneous locomotor activity was recorded for 72 hours in the open-field with an electromagnetic detector. Food intake was monitored twice daily at the end of the light (7 PM) and the dark (7 AM) phases for 3 days. Histamine H(1) receptor density in the suprachiasmatic nucleus (SCN) was examined with receptor autoradiography, employing [(3)H]pyrilamine. PCA surgery led to decreased movement time and velocity and flattened amplitude of the circadian rhythms of locomotion and feeding. In sham-operated rats, pyrilamine significantly decreased the movement time and velocity, as well as the total food consumption and completely abolished the circadian rhythmicity of locomotion. In contrast, pyrilamine increased the movement time and velocity in PCA-operated rats, particularly in the dark phase, and improved the precision of the circadian rhythms of locomotion and feeding. Histamine H(1) receptor density was not altered by PCA surgery, whereas pyrilamine treatment led to the complete blockade of H(1) receptors in both sham- and PCA-operated rats. We suggest that histaminergic imbalance has contributed to the generation and maintenance of the decreased spontaneous locomotor activity and altered circadian rhythmicity following PCA surgery in the rat, probably via an H(1) receptor-mediated mechanism.

Brain histamine levels and neocortical slow-wave activity in rats with portacaval anastomosis

To determine whether the increased histamine levels in the brain of rats with portacaval anastomosis (PCA) are associated with the development of sleep disturbances during the light phase, the neocortical slow-wave activity of PCA-operated rats was examined with electroencephalography (EEG) 1 month and 6 months after the surgery. The tissue levels of histamine, tele-methylhistamine, 5-hydroxytryptamine (5-HT) (serotonin), and 5-hydroxyindole-3-acetic acid (5-HIAA) in frontal cortex were assayed by high-performance liquid chromatography 6 months after the surgery. PCA surgery led to changes in the synchronized, low-frequency, high-amplitude frontal cortex EEG activity recorded during the light phase. Delta-wave amplitude but not delta time was significantly decreased, whereas both spindle amplitude and spindling time were significantly decreased. There were also significant age-related changes, presented as increases in the duration of spindles and the amplitude of both delta waves and spindles. PCA-operated rats showed a change in the pattern of EEG activity with increasing age similar to sham-operated rats. This suggests that once established, the resetting of the systems regulating the sleep-waking behavior is being maintained with time. The tissue levels of both histamine and metabolite in the frontal cortex were increased, whereas the serotonin system showed only an increase in the level of the metabolite. There was a significant negative correlation between the spindling time and the tissue histamine levels. We suggest that histamine, which participates in the control of vigilance, sleep, and wakefulness, as well as in the modulation of circadian rhythmicity, may play a role in the development of sleep disturbances in rats with PCA.

Diurnal and gender effects by chronic portacaval shunting in rats on spontaneous locomotor and rearing activities in an open-field

Behavioural disturbances in chronic experimental hepatic encephalopathy (HE) have been investigated for several decades, but only in recent years, the possibility for gender-dependent reduction of spontaneous locomotor activity has come under attention. Unfortunately though, the results of such gender dependency have been discrepant. We therefore performed an open-field behavior study in unhabituated female and male portacaval shunted (PCS) rats during both day- and night-time, monitoring locomotor as well as rearing activity for a 60 min period. The results revealed lower locomotor and rearing activities in both male and female PCS rats during night-time, compared to sham-operated controls. Daytime differences could only be detected in the rearing activity of female PCS versus control rats. Female PCS rats also spent less cumulated time rearing, compared to controls but no differences regarding the overall locomotor/rearing activity ratio or portion of the behaviours exerted in the central area of the open-field could be detected between PCS and controls, or between the sexes. Diurnal activity differences were found between control groups of both sexes but not between the female versus male PCS rats. Thus, our results are not supportive of any major gender-dependent behavioural disturbance between PCS and control rats.

Regional brain serotonin receptor changes in portacaval shunted rats

The pathogenesis of hepatic encephalopathy is unknown, but metabolic perturbations, including hyperammonaemia and increased brain turnover of serotonin (5-HT), have been identified. Possible alterations of 5-HT receptors in the brain have been rudimentarily studied. We therefore investigated the 5-HT1A, 5-HT1B and 5-HT2A receptor density in 18-22 different regions in the brain of portacaval shunted rats by means of radioligand binding with autoradiographical evaluation. The results revealed a decreased 5-HT1A receptor binding in seven serotonergic projection areas of the brain, and an increase in the nucleus accumbens, hypothalamus and subiculum. No changes in the raphe nuclei were observed. An increased 5-HT1B receptor binding was seen in five brain regions: basal ganglia, olfactorial regions, hippocampus, mid brain and thalamus. However, decreased binding was seen in three regions of cortical areas and hippocampus. The 5-HT2A receptor binding site density was essentially unaltered. These findings suggest that perturbations in the central serotonergic neurotransmission may play a functional role in chronic hepatic encephalopathy.

Diurnal rhythm returns to normal after elimination of portacaval shunting

Previous studies showed that portacaval shunting causes metabolic and behavioral changes in rats. Most metabolic changes reversed within 1-2 wk after restoration of normal circulation. However, the rate of cerebral glucose metabolism (CMRGlc) remained depressed in some areas. The question arose whether complete recovery was possible. Therefore, a long-term behavioral study was undertaken to determine the time course of recovery. Diurnal activity was monitored for 48 h each week over a period of 14 wk: 2 wk before shunting, 6 wk after shunting, and 6 wk after restoration of normal hepatic circulation. Nighttime activity was depressed within 1 wk of shunting and did not change. Normal circulation to the liver was reestablished after 6 wk. The diurnal cycle was normal 3 wk later. Thus, although recovery of the diurnal rhythm is possible, the relatively long period necessary suggests the correction of a significant structural or chemical abnormality. A study of CMRGlc was made using the behavioral study as an index of the time necessary for recovery. CMRGlc returned to normal throughout the brain 6 wk after cessation of shunting except in the hippocampus and amygdala (7-8% decrease).

High prevalence of sleep disturbance in cirrhosis

Sleep disturbance is a classic sign of hepatic encephalopathy. However, there are limited data regarding its prevalence in cirrhotic patients without overt hepatic encephalopathy. We assessed the characteristics of sleep in cirrhosis using a sleep questionnaire (n = 44) and actigraphy (n = 20). The results were compared with those of subjects with chronic renal failure and those of healthy controls. Presence of subclinical hepatic encephalopathy, chronotypology profile, and individual's affective state were also analyzed. The questionnaire indicated an elevated number of cirrhotic patients (47.7%) and patients with chronic renal failure (38.6%) who complained of unsatisfactory sleep compared with healthy controls (4.5%, P < .01). Actigraphy corroborated the deterioration of sleep parameters in cirrhotic patients with unsatisfactory sleep. The sleep disturbance in cirrhosis was not associated with clinical parameters nor with cognitive impairment. Cirrhotic subjects and patients with chronic renal failure with unsatisfactory sleep showed higher scores for depression and anxiety, raising the possibility that the effects of chronic disease may underlie the pathogenesis of sleep disturbance. However, in contrast to chronic renal failure, unsatisfactory sleep in cirrhosis was associated with delayed bedtime, delayed wake-up time, and evening chronotypology. In conclusion, a sleep disturbance is frequent in cirrhotic patients without hepatic encephalopathy and may be related to abnormalities of the circadian timekeeping system.

Stenosis of a portacaval anastomosis affects circadian locomotor activity in the rat: a multivariable analysis

The study of hepatic encephalopathy is limited by the lack of standardized experimental models to assess behavior. We have shown that rats continuously monitored while running on a wheel show abnormalities of the circadian rhythm of locomotor activity after portacaval anastomosis (PCA), such that entrainment of running activity to the light-dark cycle is severely impaired. To identify factors that affect postoperative circadian behavior, we have performed a multivariable analysis of 69 sham-operated controls and 107 rats after PCA. Our results indicate that shunt stenosis, as determined by the pressure gradient from the splenic pulp to the inferior vena cava, ameliorated the postoperative deterioration of the circadian rhythm. In addition, postoperative behavior was affected by preoperative performance, diet, and gender. Postoperative body weight gain, spleen weight, and liver atrophy did not impact this model. Because shunt stenosis is known to ameliorate hepatic encephalopathy in humans, our findings support the validity of this behavioral end point as a correlate of hepatic encephalopathy. Measurement of the pressure gradient across the anastomosis and achievement of sufficient preoperative entrainment appear critical for the standardization of the model.

Portal systemic encephalopathy

The goal of this article is to update the status of Portal systemic encephalopathy (PSE) in the light of new data. First, PSE is the context of other types of hepatic encephalopathy. Subsequently, current views of the pathogenesis of the disorder are discussed, followed by an analysis of therapeutic options. Diagnosis will not be considered, as no major new developments have recently been documented in this area.

Gender and diurnal effects on specific open-field behavioral patterns in the portacaval shunted rat

Hepatic encephalopathy (HE) is a frequently observed neuropsychiatric syndrome with unknown pathogenesis in patients suffering from chronic liver failure. The portacaval shunted (PCS) rat has been extensively used as an experimental model for HE and for studying the effects of portal-systemic shunting. Previous behavioral studies on PCS rats have shown a number of abnormalities but there is no consensus about which abnormalities are characteristic. We therefore made a thorough descriptive study of 100 male and female PCS rats and sham-operated controls four to six weeks after the shunting procedure in an open field. The frequency, duration and average time sequence of various kinds of defined spontaneous behavioral patterns were investigated during both night and day in order to assess behavioral differences between PCS rats and sham-operated controls. The results indicate differences especially regarding motor exploratory behaviors such as forward locomotion and rearing. There were also differences in eating and sniffing behaviors. Our results show that the overall behavioral alteration seen in PCS rats compared to sham-operated controls is that of hypoactivity.

Glutamine, myo-inositol, and organic brain osmolytes after portocaval anastomosis in the rat: implications for ammonia-induced brain edema

Brain myo-inositol, an organic osmolyte, is decreased in cirrhotic patients with hepatic encephalopathy but appears unchanged in fulminant hepatic failure. An osmoregulatory response to the increase in brain glutamine may explain the decrease in brain myo-inositol; if this is the case, organic osmolytes may account for differences in the development of brain edema seen in acute or chronic liver failure. The response of myo-inositol and nine other organic osmolytes to the increase in brain glutamine at different time intervals after portacaval anastomosis (PCA) in the rat was studied. Organic osmolytes were measured in brain tissue and cerebrospinal fluid. Water in cerebral cortex was measured after ammonia infusion with the gravimetric method. Six weeks after PCA, despite an increase in brain glutamine (PCA, 16.4 +/- 2 mmol.kg wt-1.kg wt-1; sham, 5 +/- 1 mmol.L-1.kg wt-1), the content of total organic osmolytes did not increase (PCA, 44.1 +/- 3; sham, 43 +/- 4) because of a decrease of other osmolytes (myo-inositol, 54%; urea, 39%; taurine, 33%; and glutamate, 8%). Brain myo-inositol was lower at 3 weeks (3.4 +/- 0.5 kg wt-1) than at 1 day after PCA (4.7 +/- 0.5 kg wt-1). An ammonia infusion resulted in brain edema at both time points. In conclusion, the reduction in brain myo-inositol in PCA rats is accompanied by the decrease of other organic osmolytes, supporting the view that changes in myo-inositol reflect an osmoregulatory response. The decrease in brain myo-inositol is more marked as time elapses after PCA. In a model in which short-term and large doses of ammonia were infused, the decrease in brain myo-inositol did not prevent the development of brain swelling. Understanding brain osmoregulatory mechanisms may provide new insights into hepatic encephalopathy and brain edema in fulminant hepatic failure.

Effect of probenecid on 5-hydroxyindoleacetic acid in cisternal cerebrospinal fluid of rats with portacaval anastomosis

Portal-systemic encephalopathy (PSE) is characterized by a neuropsychiatric disorder progressing through personality changes, to stupor and coma. Previous studies have revealed alterations of serotonin and of its metabolite 5-hydroxyindoleacetic acid (5-HIAA) in brain tissue and CSF in experimental (rat) and human PSE. Increased brain 5-HIAA concentrations could result from its decreased removal rather than to increased serotonin metabolism. In order to evaluate this possibility, CSF 5-HIAA concentrations were measured using an indwelling cisterna magna catheter technique at various times following end-to-side portacaval anastomosis in rats (the most widely used animal model of PSE) treated with probenecid, a competitive inhibitor that blocks the active transport of acid metabolites out of the brain and CSF. Following portacaval anastomosis and probenecid treatment, CSF concentrations of 5-HIAA were increased to a greater extent than in sham-operated controls. When data were expressed as per-cent baseline values, the relative increase of CSF 5-HIAA in portacaval shunted rats following probenecid treatment was not significantly different from sham-operated controls. These findings confirm that increased 5-HIAA in the CNS in experimental PSE results from increased 5HT metabolism or turnover and that the probenecidsensitive acid metabolite carrier is intact in PSE.

Portal-systemic shunting and the disruption of circadian locomotor activity in the rat

To determine if the extent of portal-systemic shunting (PSS) influences the disruption of circadian function in chronic liver disease, locomotor activity was examined in two rat models with varying degrees of PSS, i.e., portal vein ligation (PVL) and end-to-side portacaval anastomosis (PCA). Animals were housed in individual activity cages under conditions of 12 hour light/12 hour darkness (weeks 0-3), then under conditions of constant dim light (weeks 4-7). Cages were equipped with running wheels connected to a continuous recorder, and daily tracings of running activity were recorded for 7 weeks. Computer analysis of wheel revolutions per hour with a chi 2 periodogram was used to calculate Qp, a measure of the amplitude of a circadian rhythm. The degree of PSS was measured by means of radioactive microspheres injected into the ileocolic vein and spleen. PVL rats were found to have PSS from the splenic and mesenteric territories of 88% and 27%, respectively; circadian periodicity was maintained in all PVL rats. PCA rats had complete shunting (greater than 99%) and showed a range of disrupted circadian rhythms from blunting of the amplitude to complete absence of the locomotor activity rhythm. This spectrum of disorganization occurred in spite of similar degrees of liver atrophy and weight gain. Whereas PCA in rats markedly disturbs the circadian rhythm of locomotor activity, animals with considerably less PSS from PVL exhibit normal behavior. The extent of PSS could be a variable affecting the expression of circadian rhythms in liver disease.