Cytokines and alcohol

Effect of time, injury, age and ethanol on interpatient variability in valproic acid pharmacokinetics after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) results in an increase in hepatic metabolism. The increased metabolism is in significant contrast to a large body of in vitro and in vivo data demonstrating that activation of the host-defence response downregulates hepatic metabolism. Theoretically, this occurs because of activation of the pro-inflammatory cytokines tumour necrosis factor-alpha, interferon-gamma, interleukin (IL)-1 and IL-6. As part of a large double-blind, placebo-controlled clinical trial evaluating the use of valproic acid for prophylaxis of post-traumatic seizures, we obtained extensive valproic acid concentration-time data. Valproic acid is a hepatically metabolised, low extraction-ratio drug. Therefore, unbound clearance (CL(u)) is equal to intrinsic or metabolic clearance.

OBJECTIVE

The objective of this study was to evaluate the time-dependent effects of TBI on the pharmacokinetics of total and unbound valproic acid with the goal of identifying patient factors that may predict changes in total clearance (CL) and CL(u). In addition, by determining the factors that influence the magnitude and time course of induction of hepatic metabolism and understanding their interaction with the host-defence mediators, we can further our insight into the mechanism(s) responsible for the changes in CL and CL(u).

STUDY DESIGN

Valproic acid plasma concentration data were obtained from 158 TBI patients. Unbound valproic acid plasma concentrations were estimated using total valproic acid plasma and albumin concentrations following a Scatchard equation binding model previously developed in a subset of TBI patients. The effect of 13 patient factors on CL and CL(u) was evaluated initially in a univariate analysis. The significant factors were then included in a multiple linear regression analysis by use of step-wise selection and forward selection procedures.

RESULTS

CL and CL(u) were significantly increased after TBI in a time-dependent manner. The average increase was >75% by weeks 2 and 3 post-injury. The magnitude of the induction of CL was increased with decreased albumin concentrations, in addition to the presence of ethanol on admission, increased severity of head injury, tube feeding and total parenteral nutrition (TPN). The magnitude of induction of CL(u) was increased by older age, presence of ethanol on admission, increased severity of head injury, tube feeding, TPN, and if the patient had a post-injury neurosurgical procedure. The time to normalisation of CL(u) was significantly longer in patients with head injury plus other injuries compared with those with head injury alone.

CONCLUSIONS

As has been reported with other drugs, TBI results in a significant increase in the metabolism of valproic acid. The patient factors identified in this study that resulted in an increase in the magnitude and time course of the induction of CL(u) (ethanol, older age, presence of a neurosurgical procedure, severity of TBI and presence of multiple non-TBI injuries) have all been reported to cause a shift to the anti-inflammatory mediators IL-4 and IL-10. This suggests that the increase in hepatic metabolism after TBI may be due to the increased presence of anti-inflammatory mediators in contrast to the inhibition effect of the pro-inflammatory mediators in non-TBI inflammation and infection.

Possible mechanism of acute effect of ethanol on intestinal IgA expression in rat

The purpose of this study was to investigate the possible mechanism of acute effect of ethanol on IgA expression in rat intestine. To this end, adult female Wistar rats showing diestrus day 1 were treated with (a) ethanol (2 or 4 g/kg, i.p.); (b) N omega-nitro-L-arginine-methyl ester (L-NAME), which inhibits the activity of all isoforms of nitric oxide synthase, (30 mg/kg, s.c.) followed by ethanol 3 h later; and (c) L-NAME (30 mg/kg, s.c.) followed by saline 3 h later. Saline-injected and untreated rats were used as controls. The animals were sacrificed 0.5 h after ethanol administration. Intestinal expression of IgA was evaluated by both immunohistochemistry and Western immunoblotting. Morphometric analysis showed that acute ethanol treatment increased the number of IgA-immunoreactive cells in a dose-dependent manner. Pretreatment with L-NAME abolished this action of alcohol. Injection of L-NAME followed by saline had no influence on the number of IgA+cells. The results, obtained by Western immunoblotting, paralleled our immunohistochemical findings. Taken together, these data suggest that acute effect of ethanol on intestinal IgA might be mediated by endogenous nitric oxide.

Alcohol and the liver

PURPOSE OF REVIEW

This review aims to acquaint the reader with advances in 2006 in the epidemiology, genetics, detection, pathogenesis and treatment of alcoholic liver disease.

RECENT FINDINGS

Important discoveries have been made in pathogenesis and mechanism of disease, with great emphasis on the many pathways leading to oxidative stress, and the novel mechanism of endoplasmic reticulum stress that is proving to be important in the pathogenesis of many liver diseases. The reliability of ethyl glucuronide and other biomarkers for the detection of alcohol abuse is being better established. There have been no treatment advances for alcoholic liver disease but, on balance, steroids are still favored for carefully selected patients with alcoholic hepatitis. Many compounds tested in rodents may now be available for consideration for clinical trials. Criteria for patient selection and refusal for liver transplantation are being established but the 6 months abstinence rule still holds.

SUMMARY

Insights are being made into the pathogenesis of alcoholic liver disease but safe and effective therapies for both alcoholic hepatitis and alcoholic cirrhosis have yet to be discovered.

Prospective study of interaction between alcohol, NSAID use and polymorphisms in genes involved in the inflammatory response in relation to risk of colorectal cancer

Inflammatory bowl disease predisposes to cancer of the colorectum, and the use of non-steroidal anti-inflammatory drugs (NSAIDs) decreases the risk; hence genetic variations that modify the inflammatory response may alter the risk of colorectal cancer (CRC). The purpose of this study was to determine if polymorphisms associated with an altered inflammatory response are associated with colorectal cancer risk, and to investigate the possible interaction with lifestyle factors such as alcohol use, smoking and NSAID use. We studied 355 adenocarcinoma cases and 753 control persons, nested within the prospective "Diet, Cancer and Health" study. None of the polymorphisms were associated with risk of colorectal cancer. A statistically significant interaction between PPARgamma2 Pro(12)Ala and alcohol was found, where alcohol use was associated with a 22% increased risk of CRC per 10g alcohol/day among carriers of the variant allele but not among homozygous wild type allele carriers (P for interaction=0.02). Moreover, an interaction between DLG5 R30Q and NSAID use was found (P for interaction=0.02). Our results do not suggest that inborn variations in the inflammatory response play any major role in risk of colorectal cancer.

An inverse relationship between markers of fibrogenesis and collagen degradation in patients with or without alcoholic liver disease

OBJECTIVES

Excessive deposition of collagen leading to cirrhosis is a major complication of alcohol abuse. However, the mechanisms behind the accumulation of the extracellular matrix proteins are poorly understood.

METHODS

We measured serum markers of collagen degradation (beta-CTx), fibrogenesis (PINP, PIIINP), and pro- and anti-inflammatory cytokines from 84 male heavy drinkers, who were either with (N = 52) or without (N = 32) clinical or histological signs of alcoholic liver disease (ALD), and from 20 healthy nonalcoholic controls.

RESULTS

Serum beta-CTx levels in ALD patients were significantly lower than in healthy controls or in the alcoholics without liver disease, while PINP and PIIINP, reflecting type I and type III collagen synthesis, respectively, were significantly increased. The alcoholics without liver disease showed values, that were not significantly different from those of healthy controls. Serum beta-CTx correlated negatively with serum PIIINP and proinflammatory cytokines (IL-2, IL-6, IL-8, TNF-alpha), and positively with anti-inflammatory cytokines (IL-1, TGF-beta), whereas serum PIIINP correlated positively with these proinflammatory cytokines and negatively with the anti-inflammatory cytokines. Calculation of PIIINP/beta-CTx ratio was found to yield an excellent sensitivity (94%) and specificity (98%) in differentiating the alcoholics with liver disease.

CONCLUSION

The present findings indicate a positive relationship between markers of collagen biosynthesis and proinflammatory cytokines, and a negative relationship between these markers and a marker of collagen degradation and anti-inflammatory cytokines, suggesting that a disturbed balance in these cellular responses may facilitate fibrogenesis and play a pivotal role in the pathogenesis of ALD. These findings should also be implicated in the development of noninvasive tools for discriminating individuals at risk for fibrogenesis.

Systemic LPS causes chronic neuroinflammation and progressive neurodegeneration

Inflammation is implicated in the progressive nature of neurodegenerative diseases, such as Parkinson's disease, but the mechanisms are poorly understood. A single systemic lipopolysaccharide (LPS, 5 mg/kg, i.p.) or tumor necrosis factor alpha (TNFalpha, 0.25 mg/kg, i.p.) injection was administered in adult wild-type mice and in mice lacking TNFalpha receptors (TNF R1/R2(-/-)) to discern the mechanisms of inflammation transfer from the periphery to the brain and the neurodegenerative consequences. Systemic LPS administration resulted in rapid brain TNFalpha increase that remained elevated for 10 months, while peripheral TNFalpha (serum and liver) had subsided by 9 h (serum) and 1 week (liver). Systemic TNFalpha and LPS administration activated microglia and increased expression of brain pro-inflammatory factors (i.e., TNFalpha, MCP-1, IL-1beta, and NF-kappaB p65) in wild-type mice, but not in TNF R1/R2(-/-) mice. Further, LPS reduced the number of tyrosine hydroxylase-immunoreactive neurons in the substantia nigra (SN) by 23% at 7-months post-treatment, which progressed to 47% at 10 months. Together, these data demonstrate that through TNFalpha, peripheral inflammation in adult animals can: (1) activate brain microglia to produce chronically elevated pro-inflammatory factors; (2) induce delayed and progressive loss of DA neurons in the SN. These findings provide valuable insight into the potential pathogenesis and self-propelling nature of Parkinson's disease.

Calcitonin levels do not decrease with weaning in chronic alcoholism

OBJECTIVE

Alcohol might increase calcitonin but this assertion is mainly based on the acute effect of the drug in small animals and humans. The aim of this study was to investigate the effect of chronic alcoholic intoxication on plasma calcitonin (CT) levels.

DESIGN

20 smoking male subjects admitted to be weaned from chronic daily alcohol consumption >100 g were included after informed consent. Blood was sampled upon admission (T0) and after 5 (T5) and 21 (T21) days of alcohol weaning to measure mean erythrocyte volume, gamma-glutamyltransferase (GGT), calcium, gastrin, and CT levels. The control group consisted of 30 male subjects with daily alcohol consumption <20 g.

MAIN OUTCOME

The characteristics of the alcohol group were as follows (mean +/- SD): age 41.2 +/- 13 years old; mean erythrocyte volume: 96.0 +/- 4.2 microm(3) (N: 85-95); calcium level: 94.7 +/- 3.7 mg/L (N: 85-105); gastrinemia: 59.3 +/- 14.9 ng/mL (N: <120). At T0 and T21, three alcoholic subjects had CT levels above 10 pg/mL, usually considered as the normal cut-off value. There was no correlation between CT and the different biochemical parameters at T0, T5, and T21. There was no difference between CT levels at the different stages in the alcohol group (T0: 6.4 +/- 3.6 pg/mL; T5: 6.5 +/- 5.3 pg/mL; T21: 8.4 +/- 5.6), although GGT significantly decreased with weaning duration (T0: 248 +/- 354 IU/L; T5: 211 +/- 290 IU/L; T21: 79 +/- 90 IU/L; ANOVA, p <0.05). But a significant difference was found between mean CT levels in the alcohol group and in the control group (3.1 +/- 0.7 pg/mL, p <0.0001).

CONCLUSIONS

This study suggests that mean CT levels of chronically alcoholic smoking male subjects are higher than those of an age- and sex-matched control group. However, most alcoholic patients exhibited CT levels <10 pg/mL. No decrease in CT levels was noted over a short period of alcohol weaning. As CT measurement is currently recommended in thyroid nodule assessment, this finding may be important to know how to decipher borderline values of CT.

BHT blocks NF-kappaB activation and ethanol-induced brain damage

BACKGROUND

Binge ethanol administration causes corticolimbic brain damage that models alcoholic neurodegeneration. The mechanism of binge ethanol-induced degeneration is unknown, but is not simple glutamate-N-methyl-D-aspartate (NMDA) excitotoxicity. To test the hypothesis that oxidative stress and inflammation are mechanisms of binge ethanol-induced brain damage, we administered 4 antioxidants, e.g., butylated hydroxytoluene (BHT), ebselen (Eb), vitamin E (VE), and blueberry (BB) extract, during binge ethanol treatment and assessed various measures of neurodegeneration.

METHODS

Adult Sprague-Dawley rats were treated with intragastric ethanol 3 times per day (8-12 g/kg/d) alone or in combination with antioxidants or isocaloric diet for 4 days. Animals were killed, and brains were perfused and extracted for histochemical silver stain determination of brain damage, markers of neurogenesis, or other immunohistochemistry. Some animals were used for determination of nuclear factor kappa B (NF-kappaB)-DNA binding by electrophoretic mobility shift assay (EMSA) or for reverse transcription-polymerase chain reaction (RT-PCR) of cyclooxygenase 2 (COX2).

RESULTS

Binge ethanol induced corticolimbic brain damage and reduced neurogenesis. Treatment with BHT reversed binge induced brain damage and blocked ethanol inhibition of neurogenesis in all regions studied. Interestingly, the other antioxidants studied, e.g., Eb, VE, and BB, did not protect against binge-induced brain damage. Binge ethanol treatment also caused microglia activation, increased NF-kappaB-DNA binding and COX2 expression. Butylated hydroxytoluene reduced binge-induced NF-kappaB-DNA binding and COX2 expression.

CONCLUSIONS

Binge-induced brain damage and activation of NF-kappaB-DNA binding are blocked by BHT. These studies support a neuroinflammatory mechanism of binge ethanol-induced brain damage.

Pro-inflammatory cytokines in stable chronic alcoholics: relationship with fat and lean mass

Cytokines are mediators of the inflammatory response, secreted by many tissues, including adipocytes. Chronic alcoholic liver disease and alcoholic hepatitis are associated with elevated serum cytokine levels which yield prognostic value in this situation. Most studies have been performed in patients with acute alcoholic hepatitis. However, cytokine alterations in stable alcoholics have been less studied, as is also the case for the relationship between cytokines and fat and lean mass in these patients. The aim of the present study was to analyse the relationships between some proinflammatory serum cytokine levels and lean mass, fat mass, nutritional status, and liver function parameters in stable alcoholic patients. We determined serum TNF-alpha, interleukin (IL)-6, IL-8 and TNF receptor 2 (TNFr2) in 77 male alcoholic patients in a stable phase (before hospital discharge). In all patients we performed a total-body composition analysis (Hologic DEXA), nutritional assessment including body mass index, triceps skinfold, brachial perimeter, and assessment of liver function. Forty-two healthy volunteer health workers served as controls. IL-8, TNF-alpha and TNFr2 were significantly higher in patients than in controls. No differences were observed between patients and controls regarding fat mass, but alcoholics showed significantly decreased lean mass than controls. Only IL-6 was significantly related with body fat in patients with elevated IL-6 levels. Poor relationships were observed between lean mass and cytokines; some nutritional parameters showed inverse relationships with serum TNF, whereas TNF and IL-8 were inversely related with albumin and prothrombin activity. Thus, cytokine levels were elevated in stable alcoholic patients, and IL-6 levels showed significant correlation with body fat mass, raising the possibility that adipose tissue contributes to the persistence of high levels of cytokines in stable alcoholics.