Cytokines and alcohol

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.