Effect of oxidized low-density lipoprotein on differential gene expression in primary human endothelial cells.

Oxidative modification of low-density lipoprotein (LDL) plays an important role in the initiation and progression of atherosclerosis. It has been proposed that the biological action of oxidized LDL (ox-LDL) may be partially attributed to its effect on a shift of the pattern of gene expression in endothelial cells. To examine the transcriptional response to ox-LDL, we applied cDNA array technology to cultured primary human endothelial cells challenged with oxidized human LDL. A twofold or greater difference in the expression of a particular gene was considered a significant difference in transcript abundance. Seventy-eight of the 588 genes analyzed were differentially expressed in response to the treatment. Ox-LDL significantly affected the expression of genes encoding for transcription factors, cell receptors, growth factors, adhesion molecules, extracellular matrix proteins, and enzymes involved in cholesterol metabolism. The alteration of the expression pattern of several genes was substantiated post hoc using RT-PCR. The experimental strategy identified several novel ox-LDL-sensitive genes associated with a "response to injury" providing a conceptual background to be utilized for future studies addressing the molecular basis of the early stages of atherogenesis.

Impaired skeletal development in interleukin-6-transgenic mice: a model for the impact of chronic inflammation on the growing skeletal system.

OBJECTIVE: To identify the mediator responsible for the impact of chronic inflammation on skeletal development in children (bone loss, defective peak bone mass accrual, stunted growth), we evaluated the effects of chronic interleukin-6 (IL-6) overexpression on the skeletons of growing prepubertal mice. METHODS: We studied IL-6-transgenic mice that had high circulating IL-6 levels since birth. Trabecular and cortical bone structure were analyzed by microcomputed tomography. Epiphyseal ossification, growth plates, and calvariae were studied by histology/histomorphometry. Osteoclastogenesis, osteoblast function/differentiation, and the effects of IL-6 on bone cells were studied in vitro. Osteoblast gene expression was evaluated by reverse transcriptase-polymerase chain reaction. The mineral apposition rate was evaluated dynamically in cortical bone by in vivo double fluorescence labeling. RESULTS: In prepubertal IL-6-transgenic mice, we observed osteopenia, with severe alterations in cortical and trabecular bone microarchitecture, as well as uncoupling of bone formation from resorption, with decreased osteoblast and increased osteoclast number and activity. Increased osteoclastogenesis and reduced osteoblast activity, secondary to decreased precursor proliferation and osteoblast function, were present. IL-6-transgenic mice also showed impaired development of growth plates and epiphyseal ossification centers. Intramembranous and endochondral ossification and the mineral apposition rate were markedly affected, showing the presence of defective ossification. CONCLUSION: Chronic overexpression of IL-6 alone induces a skeletal phenotype closely resembling growth and skeletal abnormalities observed in children with chronic inflammatory diseases, pointing to IL-6 as a pivotal mediator of the impact of chronic inflammation on postnatal skeletal development. We hypothesize that IL-6-modifying drugs may reduce skeletal defects and prevent the growth retardation associated with these diseases.

Mechanistic associations of a mild phenotype of immunodysregulation, polyendocrinopathy, enteropathy, x-linked syndrome.

BACKGROUND & AIMS: The syndrome of immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a rare disorder resulting in the expression of multiple autoimmune and allergic features. Early onset enteropathy and type 1 diabetes (T1D) are the most common clinical features. The IPEX syndrome is caused by mutations of the FOXP3 gene, which is essential for the development of regulatory T cells (Treg). We describe 2 unrelated patients with IPEX syndrome with a mild clinical phenotype and with novel FOXP3 mutations and the phenotypic and functional characterization of their Treg cells. METHODS: The FOXP3 gene was analyzed by sequencing amplimers from genomic DNA. Treg cells were characterized by evaluating the number of CD4+CD25+ T cells and their functional ability to suppress the proliferation of autologous CD4+CD25- effector T cells stimulated with anti-CD3 and anti-CD28 antibodies. RESULTS: A 7-year-old boy and a 24-year-old man presented with autoimmune enteropathy characterized by early onset persistent diarrhea not associated with T1D or other endocrinopathies. These 2 patients carry novel FOXP3 mutations that do not abrogate the function of the forkhead domain. They have normal numbers of CD4+CD25+ T lymphocytes, however, these show severely defective suppressive function in vitro. CONCLUSIONS: Our 2 patients show that IPEX patients may present with early onset enteropathy and long-term survival without T1D or other endocrinopathies. This milder phenotype may be associated with FOXP3 mutations that do not abrogate the function of the forkhead domain.

Association of serum interleukin-8 levels with the degree of fibrosis in infants with chronic liver disease.

OBJECTIVE: Biliary atresia is a neonatal obstructive cholangiopathy characterized by a destructive, obliterative process affecting both the intrahepatic and extrahepatic ducts of the biliary tree that uniquely presents in the first months of life. The consequence of progressive inflammatory and sclerotic reaction is the development of obstructive jaundice. To determine the proinflammatory cytokine profile in children with biliary atresia, we measured circulating levels of interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha and IL-8. METHODS: Twelve children, five males and seven females, with biliary atresia were studied. In addition, four patients with progressive familial intrahepatic cholestasis and three with Alagille syndrome were also included. Five patients with neonatal hepatitis were studied as controls of a liver disease without portal fibrosis. Serum concentration of total and conjugated bilirubin, gamma-glutamyl transferase and glutamic-pyruvic transaminase were measured by routine methods in all patients at time of sampling for the study. The degree of fibrosis in liver biopsies was scored using the histologic activity index. RESULTS: In our study IL-8 was detectable in 11 of 12 patients with biliary atresia with a median level of 262 pg/ml and a highly statistically significant difference (P < 0.0001) from controls. In patients with progressive familial intrahepatic cholestasis or with Alagille syndrome serum IL-8 levels were similarly elevated. In patients with neonatal hepatitis, IL-8 levels were marginally increased. Serum IL-8 levels were significantly correlated (Rs = 0.725, P < 0.0001) with the histologic activity index. CONCLUSIONS: Although further studies are needed to determine the role of IL-8 in portal inflammation, our results suggest that increased production of IL-8 may be a mechanism leading to the progressive portal inflammation and fibrosis in patients with chronic liver disease.

Abnormal production of tumor necrosis factor (TNF) -- alpha and clinical efficacy of the TNF inhibitor etanercept in a patient with PAPA syndrome [corrected].

We report a family with pyogenic sterile arthritis, pyoderna and acne syndrome (PAPA). The proband presented several episodes of sterile pyogenic arthritis and became unresponsive to glucocorticoids. After treatment with the tumor necrosis factor inhibitor etanercept, the disease underwent rapid and sustained clinical remission. Production of tumor necrosis factor-alpha by mononuclear cells of the proband and of the affected relatives was abnormally elevated.