Ma C. Gutierrez-Ruiz, PhD, Luis E. Gomez Quiroz, MSc, Elizabeth Hernandez, MSc, Leticia Bucio, PhD, Veronica Souza, MSc, Luis Llorente, PhD and David Kershenobich, PhD
Background: Inflammatory mediators, including cytokines and reactive oxygen species. are associated with the pathology of chronic liver disease. Hepatocytes are generally considered as targets but not producers of these important mediators.
Objectives: To investigate whether cells of hepatocellular lineage are a potential source of various cytokines we estimated the expression and secretion of tumor necrosis factor alpha, transforming growth factor beta 1 and interleukins I beta, 6 and 8 in the culture of well-differentiated human HepG2 cells treated for 24 hours with ethanol, acetaldehyde and lipopolysaccharide. Lipid peroxidation damage, glutathione content and glutathione peroxidase, catalase and superoxide dismutase activity were also determined.
Methods: HepG2 cells were treated for 24 hours with ethanol (50 mM), acetaldehyde (175 ìM) and LPS (1 ìg/ml). TNF-á, TGF-â, L-1â, IL-6 and IL-8 mRNA were determined by reverse transcriptase polymerase chain reaction and secretion by enzyme-linked immunoassay. Lipid peroxidation damage, glutathione content and antioxidant enzyme activities were determined spectrophotometrically.
Results: Exposure to ethanol for 24 hours induced the expression of TNF-á and TGF- â1. secretion of IL-1â and TGF-â1 and decreased catalase activity. Acetaldehyde markedly increased TNF-á and IL-8 expression, stimulated IL-1â and IL-8 secretion, increased lipid peroxidation damage and decreased catalase activity, while LPS exposure induced the expression of TNF-á. TGF- â1, IL-6 and IL-8, the secretion of TGF-â1, IL-1â, IL-6 and IL-8, and a decrease in catalase activity. No change in GSH, GSHPx or SOD was found in any experimental condition.
Conclusions: The present studies confirm and extend the notion that hepatocytes respond to ethanol, acetaldehyde and LPS-producing cytokines. Oxidative stress produced by the toxic injury plays an important role in this response through upregulation of inflammatory cytokines.
Carlos Alberto Aguilar-Salinas, MD, Onix Arita Melzer, MD, Leobardo Sauque Reyna, MD, Angelina Lopez, BSc, Ma Luisa Velasco Perez, RN, Luz E. Guillen, BSc, Francisco Javier Gomez Perez, MD and Juan A. Rull Rodrigo, MD
Background: Information is lacking on the effects of hormone replacement therapy in women with diabetes, especially during moderate chronic hyperglycemia.
Objectives: To study the effects of HRT on the lipid profile and the low density lipoprotein subclass distribution in women with type 2 diabetes under satisfactory and non-satisfactory glycemic control.
Methods: Fifty-four postmenopausal women after a 6 week run-in diet were randomized to receive either placebo(HbAlc <8%, n=13 HbAlc >8%, n=17) or HRT (HbAlc<8%, n=11 HbAlc >8%, n=13) for 12 weeks. HRT consisted of cyclical conjugated estrogens 0.625 mg/day plus medrogestone 5 mg/day. At the beginning and at the end of each treatment period the LDL subclass distribution was estimated by density gradient ultracentrifugation.
Results: At the baseline and during the study, the HbAlc level was significantly higher in hyperglycemic patients than in the near-normoglycemic controls (baseline 10.2±2.9 vs. 6.5±0.7%, P<0.01). They showed a trend for higher total and LDL cholesterol, triglycerides and lower high density lipoprotein-cholesterol compared to near-normoglycemic controls, as well as significantly higher triglyceride concentrations in very low density lipoprotein, intermediate density lipoprotein and LDL-1 particles and cholesterol content in LDL-1 and -2 particles. HRT decreased LDL-cholesterol in both groups. In the normoglycemic patients a small increase in HbAlc was observed (6.5±0.7 vs. 7.4+1%, P=004). In all cases, HRT did not modify the proportion of LDL represented by denser LDLs.
Conclusions: HRT did not modify the LDL subclass distribution, even in the presence of moderate chronic hyperglycemia in women with type 2 diabetes.
Rafael J. Salin-Pascual, MD, PhD
The novel neuropeptides hypocretin/orexin have recently been located on the lateral hypothalamus cells. This system has been linked to the regulation of both feeding and sleep, and recent studies have found an association between a defect in these neuropeptides and narcolepsy. We conducted a MEDLINE review of all the articles published since the discovery of hypocretin/orexin peptides, narrowing the field to the relationship between these neuropeptides and sleep. The finding of a deletion in the transcription of the hypocretin receptor 2 gene in narcoleptic Doberman pinschers and the development of a knockout of the hypocretin gene in mice pointed to the relevance of this system in the sleep-wake cycle. We provide further evidence of the role of the hypocretin/orexin system in narcolepsy and in sleep regulation and present an integrative model of the pathophysiology of narcolepsy. The discovery of the link between these peptides and narcolepsy opens new avenues to both the understanding of sleep mechanisms and therapeutic implications for sleep disorders.
Joram Wardi, MD, Ram Reifen, MD, Hussein Aeed, PhD, Liliana Zadel, MD, Yona Avni, MD and Rafael Bruck, MD
Objective: To study whether retinolpalmitate, beta-carotene or lycopene could prevent liver cirrhosis induced by thioacetamide in rats.
Methods: In the control group liver cirrhosis was induced in male Wistar rats by intraperitoneal injections of TAA 200 mg/ kg for 12 weeks. The three study groups received in addition to TM either beta-carotene, lycopene or retinolpalmitate by gavage through an orogastric tube. Histopathological analysis and determination of the hydroxyproline contents of the livers were performed at the end of the protocol.
Results: Rats treated with beta-carotene and TAA had lower histopathologic scores and reduced levels of hepatic hydroxyproline (P= 0.02) than those treated by TAA alone. A trend of decreased fibrosis was observed in the rats treated with lycopene and TAA although this lacked statistical significance.
Conclusions: Beta-carotene attenuated liver cirrhosis induced by TAA in rats. The mechanism may be related to effects on hepatic stellate cells or to scavenging of free radicals by beta-carotene. Retinolpalmitate and lycopen had no significant beneficial effect.
Ram Silfen, MD, Jerome Keslin, MB, ChB and Haim Gutman, MD