This review highlights the inflammatory and insulin-antagonizing effects of saturated fatty acids (SFA), which contribute to the development of metabolic syndrome. Mechanisms responsible for these unhealthy effects of SFA include: 1) accumulation of diacylglycerol and ceramide; 2) activation of nuclear factor-kappaB, protein kinase C-, and mitogen-activated protein kinases, and subsequent induction of inflammatory genes in white adipose tissue, immune cells, and myotubes; 3) decreased PPARgamma coactivator-1 alpha/beta activation and adiponectin production, which decreases the oxidation of glucose and fatty acids (FA); and 4) recruitment of immune cells like macrophages, neutrophils, and bone marrow-derived dendritic cells to WAT and muscle. Several studies have demonstrated potential health benefits of substituting SFA with unsaturated FA, particularly oleic acid and (n-3) FA. Thus, reducing consumption of foods rich in SFA and increasing consumption of whole grains, fruits, vegetables, lean meats and poultry, fish, low-fat dairy products, and oils containing oleic acid or (n-3) FA is likely to reduce the incidence of metabolic disease.

BACKGROUND

MicroRNAs (miRNAs) are small, noncoding RNAs that regulate gene expression at posttranscriptional level. H. pylori is a major human pathogenic bacterium in gastric mucosa. To date, the role of miRNAs in response to H. pylori infection has not been explored.

METHODS

The expression profile of cellular miRNAs during H. pylori infection was analyzed by using microarray and quantitative reverse-transcriptase polymerase chain reaction. The potential target of miR-155 was identified by luciferase assay and Western blot. Promoter analysis and inhibitor experiment were used to investigate the pathway involved in the induction of miR-155. Examination of miR-155 function was performed by overexpression and inhibition of miR-155.

RESULTS

H. pylori was able to increase the miR-155 expression in gastric epithelial cell lines and gastric mucosal tissues, and nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) pathway were required for the induction of miR-155. miR-155 may down-regulate IkappaB kinase epsilon, Sma- and Mad-related protein 2 (SMAD2), and Fas-associated death domain protein. Furthermore, the overexpression of miR-155 negatively regulated the release of interleukin-8 and growth-related oncogene-alpha.

CONCLUSIONS

This study provides the first description of increased expression of miR-155 in H. pylori infection, and miR-155 may function as novel negative regulator that help to fine-tune the inflammation response of H. pylori infection.

A large body of data gathered over the past couple of years has identified the peroxisome proliferator-activated receptors (PPAR) alpha, gamma, and beta/delta as transcription factors exerting modulatory actions in vascular cells. PPARs, which belong to the nuclear receptor family of ligand-activated transcription factors, were originally described as gene regulators of various metabolic pathways. Although the PPARalpha, gamma, and beta/delta subtypes are approximately 60% to 80% homologous in their ligand- and DNA-binding domains, significant differences in ligand and target gene specificities are observed. PPARalpha is activated by polyunsaturated fatty acids and oxidized derivatives and by lipid-modifying drugs of the fibrate family, including fenofibrate or gemfibrozil. PPARalpha controls expression of genes implicated in lipid metabolism. PPARgamma, in contrast, is a key regulator of glucose homeostasis and adipogenesis. Ligands of PPARgamma include naturally occurring FA derivatives, such as hydroxyoctadecadienoic acids (HODEs), prostaglandin derivatives such as 15-deoxyDelta12,14-prostaglandin J2, and glitazones, insulin-sensitizing drugs presently used to treat patients with type 2 diabetes. Ligands for PPARbeta/delta are polyunsaturated fatty acids, prostaglandins, and synthetic compounds, some of which are presently in clinical development. PPARbeta/delta stimulates fatty acid oxidation predominantly acting in muscle. All PPARs are expressed in vascular cells, where they exhibit antiinflammatory and antiatherogenic properties. In addition, studies in various animal models as well as clinical data suggest that PPARalpha and PPARgamma activators can modulate atherogenesis in vivo. At present, no data are available relating to possible effects of PPARbeta/delta agonists on atherogenesis. Given the widespread use of PPARalpha and PPARgamma agonists in patients at high risk for cardiovascular disease, the understanding of their function in the vasculature is not only of basic interest but also has important clinical implications. This review will focus on the role of PPARs in the vasculature and summarize the present understanding of their effects on atherogenesis and its cardiovascular complications.

Fatty acids are synthesized de novo from acetyl-CoA and malonyl-CoA through a series of reactions mediated by acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS). In rodents, the principal fatty acid produced by FAS is palmitic acid (16:0). Sterol regulatory element-binding proteins (SREBPs) enhance the transcription of many genes responsible for fatty acid synthesis. In transgenic mice that overexpress SREBPs in liver, the rate of fatty acid synthesis is markedly increased, owing to the activation of these biosynthetic genes, which include ATP citrate lyase, ACC, FAS, and stearoyl-CoA desaturase. The fatty acids that accumulate in livers of SREBP transgenic mice are 18 carbons rather than 16 carbons in length, suggesting that the enzymes required for the elongation of palmitic to stearic acid may be induced. Here, we report the cDNA cloning of a murine long chain fatty acyl elongase (LCE) that was identified initially by oligonucleotide array analysis of mRNA from SREBP transgenic mouse livers. LCE mRNA is highly expressed in liver and adipose tissue. The cDNA encodes a protein of 267 amino acids that shares sequence identity with previously identified very long chain fatty acid elongases. Cells that overexpress LCE show enhanced addition of 2-carbon units to C12-C16 fatty acids. We provide evidence that LCE catalyzes the rate-limiting condensing step in this reaction. The current studies suggest that mouse LCE expression is increased by SREBPs and that the enzyme is a component of the elusive mammalian elongation system that converts palmitic to stearic acid.

Integrin binding to matrix proteins such as fibronectin (FN) leads to formation of focal adhesion (FA) cellular contact sites that regulate migration. RhoA GTPases facilitate FA formation, yet FA-associated RhoA-specific guanine nucleotide exchange factors (GEFs) remain unknown. Here, we show that proline-rich kinase-2 (Pyk2) levels increase upon loss of focal adhesion kinase (FAK) in mouse embryonic fibroblasts (MEFs). Additionally, we demonstrate that Pyk2 facilitates deregulated RhoA activation, elevated FA formation, and enhanced cell proliferation by promoting p190RhoGEF expression. In normal MEFs, p190RhoGEF knockdown inhibits FN-associated RhoA activation, FA formation, and cell migration. Knockdown of p190RhoGEF-related GEFH1 does not affect FA formation in FAK(-/-) or normal MEFs. p190RhoGEF overexpression enhances RhoA activation and FA formation in MEFs dependent on FAK binding and associated with p190RhoGEF FA recruitment and tyrosine phosphorylation. These studies elucidate a compensatory function for Pyk2 upon FAK loss and identify the FAK-p190RhoGEF complex as an important integrin-proximal regulator of FA formation during FN-stimulated cell motility.

BACKGROUND

Fanconi anemia (FA) is an autosomal recessive disease associated with an abnormal response to DNA damage. Although FA is well known for the association of aplastic anemia and characteristic birth defects, leukemia and solid tumors also occur at a high rate in this group of patients. A review of all reported cases is informative with regard to the specific types of cancer, the ages at which they occur, and the cumulative probability of their development.

METHODS

Medline and bibliographies of publications were searched for articles containing "Fanconi's anemia" or "aplastic anemia" and all cases of FA from 1927 through 2001 were included in the database. Cancer cases were identified within these reports. Descriptive statistical analyses were performed using Stata7 software.

RESULTS

One thousand three hundred cases of FA were identified. Nine percent had leukemia (primarily acute myeloid leukemia), 7% had myelodysplastic syndrome, 5% had solid tumors, and 3% had liver tumors. Patients with cancer were older than the cancer-free patients at the time of diagnosis of FA. The median age for cancer (including leukemia) was 16, compared with 68 in the general population. The most frequent solid tumors were aerodigestive and gynecological carcinomas. In approximately 25% of patients with cancer, the malignancy preceded the diagnosis of FA.

CONCLUSIONS

If the competing risks of aplastic anemia and leukemia could be removed, the estimated cumulative probability of development of a solid tumor in FA patients is 76% by the age of 45 years. Carcinogenic pathways and cancer prevention, surveillance, and treatment can be studied to advantage in this genetic model of human cancer.

Measures are needed that identify persons that will develop Alzheimer's disease in order to target them for preventative interventions. There is evidence from animal, pathological and imaging studies that disruption of white matter occurs in the course of Alzheimer's disease and may be an early event. Prior studies have suggested that late-myelinating regions or white matter connecting limbic structures are particularly susceptible to degradation. Persons destined to develop the disease by virtue of fully penetrant genetic alterations (familial Alzheimer's disease or FAD) provide a model in which early and even presymptomatic changes of the disease may be identified. In this study we performed diffusion tensor imaging (DTI) on 2 demented and 21 subjects at-risk for inheriting an FAD mutation. We compared global and localized fractional anisotropy (FA) measures in white matter between FAD mutation carriers and non-carriers in the preclinical (clinical dementia rating <1, n = 20) and presymptomatic (clinical dementia rating = 0, n = 15) stages of the disease. There were no significant differences between mutation carriers and non-carriers with regard to absolute age, age relative to the typical age of disease diagnosis in their family, gender or Mini-Mental Status Examination Score. Among preclinical FAD mutation carriers (n = 12), mean whole brain white-matter FA (P = 0.045), FA of the columns of the fornix (P = 0.012), area of the perforant pathways bilaterally (right side: P = 0.028, left side: P = 0.027) and left orbitofrontal lobe (P = 0.024) were decreased relative to that of non-carriers (n = 8). We also found that FA in the columns of the fornix (P = 0.008) and left orbitofrontal lobe white matter (P = 0.045) were decreased in the eight presymptomatic mutation carriers compared to seven non-carriers. Logistic regression demonstrated that FA of the columns of the fornix was a better predictor of mutation status than was cross-sectional area of the fornix, global mean white-matter FA and left frontal lobe white-matter FA. In a linear regression analysis, white-matter volume (P = 0.002), hippocampal volume (P = 0.023) and mutation status (P = 0.032) significantly predicted fornix FA. We conclude that FA is decreased in the white matter in preclinical and even presymptomatic FAD mutation carriers, particularly in the late-myelinating tracts connecting limbic structures. Decreased FA in of the columns of the fornix is particularly robust in early FAD and may provide a biomarker for early disease in sporadic Alzheimer's disease.

Optical coherence tomography angiography (OCTA) is a new, non-invasive imaging technique that generates volumetric angiography images in a matter of seconds. This is a nascent technology with a potential wide applicability for retinal vascular disease. At present, level 1 evidence of the technology's clinical applications doesn't exist. In this paper, we introduce the technology, review the available English language publications regarding OCTA, and compare it with the current angiographic gold standards, fluorescein angiography (FA) and indocyanine green angiography (ICGA). Finally we summarize its potential application to retinal vascular diseases. OCTA is quick and non-invasive, and provides volumetric data with the clinical capability of specifically localizing and delineating pathology along with the ability to show both structural and blood flow information in tandem. Its current limitations include a relatively small field of view, inability to show leakage, and proclivity for image artifact due to patient movement/blinking. Published studies hint at OCTA's potential efficacy in the evaluation of common ophthalmologic diseases such age related macular degeneration (AMD), diabetic retinopathy, artery and vein occlusions, and glaucoma. OCTA can detect changes in choroidal blood vessel flow and can elucidate the presence of choroidal neovascularization (CNV) in a variety of conditions but especially in AMD. It provides a highly detailed view of the retinal vasculature, which allows for accurate delineation of the foveal avascular zone (FAZ) in diabetic eyes and detection of subtle microvascular abnormalities in diabetic and vascular occlusive eyes. Optic disc perfusion in glaucomatous eyes is notable as well on OCTA. Further studies are needed to more definitively determine OCTA's utility in the clinical setting and to establish if this technology may offer a non-invasive option of visualizing the retinal vasculature in detail.

An experimental method and its associated mathematical model are described to quantitate in vivo incorporation rates into and turnovers of fatty acids (FAs) within stable brain metabolic compartments, particularly phospholipids. A radiolabeled FA is injected i.v. in a rat, and arterial plasma unacylated FA radioactivities and unlabeled concentrations are sampled until the animal is killed after 15 min, when the brain is analyzed biochemically or with quantitative autoradiography. Unbound unacylated label in blood easily crosses the blood-brain barrier; rapidly equilibrates in the unacylated FA, acyl-CoA and phosphatidate-diacylglycerol brain pools; then is incorporated into phospholipids and other stable metabolic compartments. Uptake and incorporation of labeled FAs are independent of cerebral blood flow at constant brain blood volume. Different labeled FAs enter specific sn positions of different brain phospholipids, suggesting that a combination of probes can be used to investigate metabolism of these phospholipids. Thus, [9,10-3-H]palmitate preferentially labels the sn1 position of phosphatidylcholine; [1-14C]arachidonate the sn2 positions of phosphatidylinositol and phosphatidylcholine; and [1-14C]docosahexaenoate the sn2 positions of phosphatidylethanolamine and phosphatidylcholine. The FA model provides an operational equation for rates of incorporation of FAs into brain phospholipids, taking into account intracerebral recycling and de novo synthesis of the FA, as well as entry into brain of FA from acylated blood sources. The equation is essentially independent of specific details of the proposed model, and can be used to calculate turnovers and half-lives of FAs within different phospholipid classes. For the model to be most applicable, experiments should satisfy conditions for pulse-labeling of the phospholipids, with brain sampling times short enough to minimize exchange of label between stable metabolic compartments. A 15-20 min sampling time satisfies these criteria. The FA method has been used to elucidate the dynamics of brain phospholipids metabolism in relation to brain development, brain tumor, chronically reduced auditory input, transient ischemic insult, axotomy with and without nerve regeneration, and cholinergic stimulation in animals with or without a chronic unilateral lesion of the nucleus basalis magnocellularis.

Chemotherapeutic drugs are cytotoxic by induction of apoptosis in drug-sensitive cells. We investigated the mechanism of bleomycin-induced cytotoxicity in hepatoma cells. At concentrations present in the sera of patients during therapy, bleomycin induced transient accumulation of nuclear wild-type (wt) p53 and upregulated expression of cell surface CD95 (APO-1/Fas) receptor in hepatoma cells carrying wt p53 (HepG2). Bleomycin did not increase CD95 in hepatoma cells with mutated p53 (Huh7) or in hepatoma cells which were p53-/- (Hep3B). In addition, sensitivity towards CD95-mediated apoptosis was also increased in wt p53 positive HepG2 cells. Microinjection of wt p53 cDNA into HepG2 cells had the same effect. In contrast, bleomycin did not enhance susceptibility towards CD95-mediated apoptosis in Huh7 and in Hep3B cells. Furthermore, bleomycin treatment of HepG2 cells increased CD95 ligand (CD95L) mRNA expression. Most notably, bleomycin-induced apoptosis in HepG2 cells was almost completely inhibited by antibodies which interfere with CD95 receptor/ligand interaction. These data suggest that apoptosis induced by bleomycin is mediated, at least in part, by p53-dependent stimulation of the CD95 receptor/ligand system. The same applies to other anti-cancer drugs such as cisplatin and methotrexate. These data may have major consequences for drug treatment of cancer and the explanation of drug sensitivity and resistance.

Very low birth weight (VLBW) children are at high risk of perinatal white matter injury, which, when subtle, may not be seen using conventional magnetic resonance imaging. The relationship between clinical findings and fractional anisotropy (<em>FA</em>) measurements in white matter of adolescents born prematurely with VLBW was studied in 34 subjects (age = 15 years, birth weight </=1500 g) and 47 age-matched controls born at term, who were examined both clinically and with diffusion tensor imaging (DTI). Perceptual and cognitive functions were evaluated by visual motor integration (VMI) with supplementary tests and sub-tests from WISC-III, motor function by movement ABC and Grooved Pegboard test and psychiatric symptoms by the schedule for affective disorders and schizophrenia for school-age children semistructured interview, the Autism Spectrum Screening Questionnaire and attention deficit hyperactivity disorder (ADHD) rating scale IV. Overall functioning was scored on the children's global assessment scale. DTI scans were performed for calculation of <em>FA</em> maps and areas of significant differences in mean <em>FA</em> values between subjects and controls were compared with their clinical data. The VLBW children had reduced <em>FA</em> values in the internal and external capsule, corpus callosum and superior, middle superior and inferior fasciculus. Within this group of children, visual motor and visual perceptual deficits were associated with low <em>FA</em> values in the external capsule, posterior part of the internal capsule and in the inferior fasciculus. Children with low IQ had low <em>FA</em> values in the external capsule and inferior and middle superior fasciculus. Fine motor impairment was related to low <em>FA</em> values in the internal and external capsule and superior fasciculus. Eight VLBW children with inattention symptoms or a diagnosis of ADHD had significantly lower <em>FA</em> values in several areas. Mild social deficits correlated with reduced <em>FA</em> values in the external capsule and superior fasciculus. We conclude that DTI was able to detect differences in <em>FA</em> between VLBW adolescents and controls in several white matter areas at risk of periventricular leucomalacia in VLBW newborns. Our results show that low <em>FA</em> values in these areas were associated with perceptual, cognitive, motor and mental health impairments. These conclusions indicate that perinatal injury of white matter tracts persist with clinical significance in adolescence.

Cancer is one of the most devastating disorders in our lives. Higher rate of proliferation than death of cells is one of the essential factors for development of cancer. The dynamicity of cell membrane plays some vital roles in cell survival and cell death, including protection, endocytosis, signaling, and increases in mechanical stability during cell division, as well as decrease of shear forces during separation of two cells after division, and cell separation from tissues for cancer metastasis. Within the membrane, there are specialized domains, known as lipid rafts. A raft can coordinate various signaling pathways. Recent data on the proteomics of lipid rafts/caveolae have highlighted the enigmatic role of various signaling proteins in cancer development. Analysis of these data of raft proteome from various tumors, cancer tissues, and cell lines cultured without and with therapeutic agents, as well as from model rafts revealed that there may be two subsets of raft assemblage in cell membrane. One subset of raft is enriched with cholesterol-sphingomyeline-ganglioside-cav-1/Src/EGFR (hereafter, "chol-raft") that is involved in normal cell signaling, and when dysregulated promotes cell transformation and tumor progression; another subset of raft is enriched with ceramide-sphingomyeline-ganglioside-FAS/Ezrin (hereafter, "cer-raft") that generally promotes apoptosis. In view of this, and to focus insight into the cancer cell physiology caused by the lipid rafts mediated signals and their receptors, and the downstream transmitters, either proliferative (for example, EGF and EGFR) or death-inducing (for example, FASL and FAS), and the precise roles of some therapeutic drugs and endogenous acid sphingomylenase in this scenario in in situ transformation of "chol-raft" into "cer-raft" are summarized and discussed in this contribution.

Pathogens specifically target both the caspase 8-dependent apoptotic cell death pathway and the necrotic cell death pathway that is dependent on receptor-interacting protein 1 (RIP1; also known as RIPK1) and RIP3 (also known as RIPK3). The fundamental co-regulation of these two cell death pathways emerged when the midgestational death of mice deficient in FAS-associated death domain protein (FADD) or caspase 8 was reversed by elimination of RIP1 or RIP3, indicating a far more entwined relationship than previously appreciated. Thus, mammals require caspase 8 activity during embryogenesis to suppress the kinases RIP1 and RIP3 as part of the dialogue between two distinct cell death processes that together fulfil reinforcing roles in the host defence against intracellular pathogens such as herpesviruses.

Extracellular signals are the key components of microbial cell-cell communication systems. This report identified a diffusible signal factor (DSF), which regulates virulence in Xanthomonas campestris pv. campestris, as cis-11-methyl-2-dodecenoic acid, an alpha,beta unsaturated fatty acid. Analysis of DSF derivatives established the double bond at the alpha,beta positions as the most important structural feature for DSF biological activity. A range of bacterial pathogens, including several Mycobacterium species, also displayed DSF-like activity. Furthermore, DSF is structurally and functionally related to farnesoic acid (FA), which regulates morphological transition and virulence by Candida albicans, a fungal pathogen. Similar to FA, which is also an alpha,beta unsaturated fatty acid, DSF inhibits the dimorphic transition of C. albicans at a physiologically relevant concentration. We conclude that alpha,beta unsaturated fatty acids represent a new class of extracellular signals for bacterial and fungal cell-cell communications. As prokaryote-eukaryote interactions are ubiquitous, such cross-kingdom conservation in cell-cell communication systems might have significant ecological and economic importance.

OBJECTIVE

To quantify, using diffusion tensor imaging (DTI), the tissue damage in lesions and normal-appearing white matter (NAWM) from a large cohort of patients with MS and to investigate the magnitude of the correlation between DTI-derived metrics and clinical disability.

METHODS

Dual-echo and DTI scans were obtained from 78 patients with relapsing-remitting, secondary progressive, or primary progressive MS and from 20 normal control participants. Post-contrast T1-weighted images were also obtained from the patients. After creating mean diffusivity (D) and fractional anisotropy (FA) images and image coregistration, D and FA values were measured for 4846 lesions (3207 nonenhancing T1-isointense, 1511 nonenhancing T1-hypointense, and 128 enhancing), 497 NAWM areas from patients, and 160 white matter areas from the controls.

RESULTS

The average lesion D was higher and the average lesion FA was lower than the corresponding quantities of the NAWM (p < 0.001). The values of enhancing and nonenhancing lesions were not different, whereas enhancing lesions had lower FA (p < 0.001). T1-hypointense lesions had higher D and lower FA than T1-isointense lesions (p < 0.001). NAWM of patients had higher and lower FA than white matter of controls (p = 0.01). Significant correlations were found between T1 and T2 lesion volume and and FA of lesions and NAWM. In the overall patient sample, a moderate correlation was also found between lesion D and the Expanded Disability Status Scale score (r = 0.28, p = 0.01). However, the r value of this correlation was 0.48 in patients with secondary progressive MS, whose disability was also correlated with average lesion FA (r = -0.50).

CONCLUSIONS

The results of this study show that DTI is able to identify MS lesions with severe tissue damage and to detect changes in the NAWM. They also indicate that DTI-derived measures are correlated with clinical disability, especially in patients with secondary progressive MS, thus suggesting a role for DTI in monitoring advanced phases of the disease.

A strong glial reaction typically surrounds the affected upper and lower motor neurons and degenerating descending tracts of ALS patients. Reactive astrocytes in ALS contain protein inclusions, express inflammatory makers such as the inducible forms of nitric oxide synthase (iNOS) and cyclooxygenase (COX-2), display nitrotyrosine immunoreactivity and downregulate the glutamate transporter EAAT2. In this review, we discuss the evidence sustaining an active role for astrocytes in the induction and propagation of motor neuron loss in ALS. Available evidence supports the view that glial activation could be initiated by proinflammatory mediators secreted by motor neurons in response to injury, axotomy or muscular pathology. In turn, reactive astrocytes produce nitric oxide and peroxynitrite, which cause mitochondrial damage in cultured neurons and trigger apoptosis in motor neurons. Astrocytes may also contribute to the excitotoxic damage of motor neurons by decreasing glutamate transport or actively releasing the excitotoxic amino acid. In addition, reactive astrocytes secrete pro-apoptotic mediators, such as nerve growth factor (NGF) or Fas-ligand, a mechanism that may serve to eliminate vulnerable motor neurons. The comprehensive understanding of the interactions between motor neurons and glia in ALS may lead to a more accurate theory of the pathogenesis of the disease.

Originally identified as a cell surface receptor that triggered the death of lymphocytes and tumor cells, it is now recognized that Fas (also known as CD95 or Apo-I) has distinct functions in the life and death of different cell types in the immune system. Fas signaling may also be involved in T cell costimulation and proliferation. Although Fas deficiency in humans and mice predisposes them towards systemic autoimmunity, Fas-FasL interactions can also facilitate organ-specific immunopathology. Proximal signaling by Fas and related receptors depends on subunit preassembly, which accounts for the dominant-negative effect of pathogenic receptor mutants and natural splice variants.

Congenic MRL-lpr mice homozygous and heterozygous for the IFN-gamma gene disruption were created to assess the role of this pleotropic cytokine on the lymphoaccumulation and lupus-like disease of Fas-defective mice. Early death was prevented, and glomerulonephritis severely reduced in IFN-gamma-/- mice. Hypergammaglobulinemia was maintained with a switch from IgG2a to IgG1 predominance, but the dramatic decrease in levels of the dominant IgG2a anti-dsDNA autoantibodies was not associated with a compensatory increase in TH2-associated IgG subclasses. Remarkably, early death and glomerulonephritis were also prevented in IFN-gamma+/- mice, although autoantibody levels and glomerular immune deposits were equivalent to IFN-gamma+/+ lpr mice, indicating the importance of additional locally-exerted disease-promoting effects of IFN-gamma. IFN-gamma-/- mice exhibited reduced lymphadenopathy concomitant to a decrease in DN B220(+) T cells. In vivo BrdU labeling showed reduced proliferation of DN B220(+) cells in IFN-gamma-/- vs. IFN-gamma+/+ lpr mice, while enhanced proliferation of all other T cell subsets was unaffected. Macrophages of IFN-gamma-/-lpr mice expressed markedly decreased levels of MHC class I and II molecules compared with controls. Moreover, the heightened expression of MHC class II molecules on proximal tubules of IFN-gamma+/+ lpr mice was significantly reduced in both IFN-gamma-/- and IFN-gamma+/- mice. The data indicate that IFN-gamma hyperproduction is required for lupus development, presumably by increasing MHC expression and autoantigen presentation to otherwise quiescent nontolerant anti-self T cells, and also by promoting local immune and inflammatory processes.

To investigate frontal lobe white matter in children with autism spectrum disorder (ASD), we performed diffusion tensor imaging (DTI) in 50 ASD children (mean age: 57.5 +/- 29.2 months, 43 males) and 16 typically developing children (mean age: 82.1 +/- 41.4 months, 11 males). The apparent diffusion coefficient (ADC) was significantly higher for whole frontal lobe (P = 0.011), long (P < 0.001) and short range (P = 0.0126) association fibers in ASD group. There was a trend toward statistical significance in the fractional anisotropy (FA) of whole frontal lobe fibers (P = 0.11). FA was significantly lower in ASD group for short range fibers (P = 0.0031) but not for long range fibers (P = not significant [NS]). There was no between-group difference in the number of frontal lobe fibers (short and long) (P = NS). The fiber length distribution was significantly more positively skewed in the normal population than in the ASD group (P < 0.001). The long range association fibers of frontal lobe were significantly longer in ASD group (P = 0.026 for both left and right hemispheres). Abnormal frontal FA and ADC may be due to white matter organization abnormalities in ASD. Lack of evidence for excessive short range connectivity in ASD in this study may need to be re-examined with future advances in DTI technology.

Cells obtain FAs either from LPL-catalyzed hydrolysis of lipoprotein triglyceride or from unesterified FFAs associated with albumin. LPL also influences uptake of esterified lipids such as cholesteryl and retinyl esters that are not hydrolyzed in the plasma. This process might not involve LPL enzymatic activity. LPL is regulated by feeding/fasting, insulin, and exercise. Although a number of molecules may affect cellular uptake of FFAs, the best characterized is CD36. Genetic deletion of this multiligand receptor reduces FFA uptake into skeletal muscle, heart, and adipose tissue, and impairs intestinal chylomicron production and clearance of lipoproteins from the blood. CD36 is regulated by some of the same factors that regulate LPL, including insulin, muscle contraction, and fasting, in part, via ubiquitination. LPL and CD36 actions in various tissues coordinate biodistribution of fat-derived calories.

The Fas Ag is a newly defined cell-surface molecule that may mediate apoptosis. The antibody against Fas Ag can induce the apoptotic cell death in cell lines expressing this Ag. PBL subpopulations at various ages were here examined for Fas expression by two-or three-color flow-cytometric analyses using anti-Fas mAb. It was found that Fas Ag was appreciably detected on a proportion of T and B cells, whereas its expression was absent for NK cells. For CD4+ and CD8+ T cells, Fas Ag was expressed preferentially on CD45RO+ (memory or previously activated) populations, but not on CD45RO- naive ones. TCR-gamma/delta+ T cells, especially their CD45RO+ subsets, also expressed Fas Ag. Expectably, neonatal T cell subpopulations, most of which had the naive (CD45RO-) phenotype, expressed little Fas Ag. Fas-expressing B cells dominated in surface(s) IgD- populations, but neonatal B cells as well as adult sIgD+ B cells had little Fas Ag. The Fas Ag was inducible after in vitro mitogenic stimulation of naive T and B cells from neonatal blood. These observations suggested that expression of Fas Ag on T and B cells in the peripheral blood might reflect their in vivo Ag-activated status. In contrast to Fas-expressing cultured cell lines, however, viability of in vitro stimulated T and B cells as well as freshly isolated CD45RO+ T cells was not significantly changed after the treatment with anti-Fas mAb, indicating that additional cellular conditions to Fas expression might be required for anti-Fas-induced cell death.

Cellular caspase-8 (FLICE)-like inhibitory protein (cFLIP) was originally identified as an inhibitor of death-receptor signalling through competition with caspase-8 for recruitment to FAS-associated via death domain (FADD). More recently, it has been determined that both cFLIP and caspase-8 are required for the survival and proliferation of T cells following T-cell-receptor stimulation. This paradoxical finding launched new investigations of how these molecules might connect with signalling pathways that link to cell survival and growth following antigen-receptor activation. As discussed in this Review, insight gained from these studies indicates that cFLIP and caspase-8 form a heterodimer that ultimately links T-cell-receptor signalling to activation of nuclear factor-kappaB through a complex that includes B-cell lymphoma 10 (BCL-10), mucosa-associated-lymphoid-tissue lymphoma-translocation gene 1 (MALT1) and receptor-interacting protein 1 (RIP1).

Recent evidence from several groups indicates that IL-17-producing Th17 cells, rather than, as once was thought, IFN-gamma-producing Th1 cells, can represent the key effector cells in the induction/development of several autoimmune and allergic disorders. Although Th17 cells exhibit certain phenotypic and developmental differences from Th1 cells, the extent of the differences between these two T cell subsets is still not fully understood. We found that the expression profile of cell surface molecules on Th17 cells has more similarities to that of Th1 cells than Th2 cells. However, although certain Th1-lineage markers [i.e., IL-18 receptor alpha, CXCR3, and T cell Ig domain, mucin-like domain-3 (TIM-3)], but not Th2-lineage markers (i.e., T1/ST2, TIM-1, and TIM-2), were expressed on Th17 cells, the intensity of expression was different between Th17 and Th1 cells. Moreover, the expression of CTLA-1, ICOS, programmed death ligand 1, CD153, Fas, and TNF-related activation-induced cytokine was greater on Th17 cells than on Th1 cells. We found that IL-23 or IL-17 can suppress Th1 cell differentiation in the presence of exogenous IL-12 in vitro. We also confirmed that IL-12 or IFN-gamma can negatively regulate Th17 cell differentiation. However, these cytokines could not modulate such effects on T cell differentiation in the absence of APC.

OBJECTIVE

To describe risk factors for geographic atrophy (GA) in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT).

METHODS

Cohort within a randomized clinical trial.

METHODS

We analyzed 1024 CATT patients with no GA visible on color fundus photographs (CFPs) and/or fluorescein angiograms (FAs) at enrollment.

METHODS

Eyes were assigned to ranibizumab (0.5 mg) or bevacizumab (1.25 mg) treatment and to a 2-year monthly or pro re nata (PRN) injection regimen, or monthly injections for 1 year and PRN for 1 year. Demographic, genetic, and baseline ocular characteristics and lesion features of CFP/FA and optical coherence tomography (OCT) were evaluated as risk factors for GA through 2 years of follow-up. Time-dependent Cox proportional hazard models were used to estimate adjusted hazard ratios (aHRs).

METHODS

Development of GA.

RESULTS

By 2 years, GA developed in 187 of 1024 patients (18.3%). Baseline risk factors for GA development included baseline visual acuity (VA) ≤20/200 (aHR, 2.65; 95% confidence interval [CI], 1.43-4.93), retinal angiomatous proliferation (RAP; aHR, 1.69; 95% CI, 1.16-2.47), GA in the fellow eye (aHR, 2.07; 95% CI, 1.40-3.08), and intraretinal fluid at the foveal center (aHR, 2.10; 95% CI, 1.34-3.31). Baseline factors associated with lower risk for GA development included blocked fluorescence (aHR, 0.49; 95% CI, 0.29-0.82), OCT measurements of subretinal fluid thickness of >25 μ (aHR, 0.52; 95% CI, 0.35-0.78), subretinal tissue complex thickness of >275 compared with ≤75 μ (aHR, 0.31; 95% CI, 0.19-0.50), and vitreomacular attachment (aHR, 0.55; 95% CI, 0.31-0.97). Ranibizumab compared with bevacizumab had a higher risk (aHR, 1.43; 95% CI, 1.06-1.93), and monthly dosing had a higher risk (aHR, 1.59; 95% CI, 1.17-2.16) than PRN dosing. There were no strong associations between development of GA and the presence of risk alleles for CFH, ARMS 2, HTRA1, C3, or TLR3.

CONCLUSIONS

Approximately one fifth of CATT patients developed GA within 2 years of treatment. Independent baseline risk factors included poor VA, RAP, foveal intraretinal fluid, monthly dosing, and treatment with ranibizumab. Anti-vascular endothelial growth factor therapy may have a role in the development of GA.