PPARγ Variant Influences Angiographic Outcome and 10-Year Cardiovascular Risk in Male Symptomatic Coronary Artery Disease Patients

OBJECTIVE: Activation of peroxisome proliferator-activated receptor (PPAR)-gamma signaling influences metabolic profiles and the propensity toward inflammation. Small-molecule stimulation of PPARgamma is investigated for secondary prevention of cardiovascular disease. The common PPARgamma Pro12Ala variant has functional and prognostic consequences. A protective effect of the 12Ala-allele carriership on diabetes and myocardial infarction in healthy populations has been suggested. The relevance of this pathway also needs exploration in patients with manifest vascular disease. We investigated the effects of carriership of the Pro12Ala variant on angiographic and cardiovascular event outcomes in male patients with symptomatic coronary artery disease (CAD). RESEARCH DESIGN AND METHODS: The Regression Growth Evaluation Statin Study (REGRESS) cohort was genotyped for the Pro12Ala variant (rs1801282). Ten-year follow-up was derived from nation-wide registries, and risks were estimated using proportional hazards. Quantitative coronary angiography measurements were obtained and relations with genotype estimated using a generalized linear model. RESULTS: Genotypes ascertained (n = 679) comprised 540 (80%) Pro/Pro, 126 (19%) Pro/Ala, and 13 (2%) Ala/Ala subjects. The 12Ala allele was associated with less extensive focal (P = 0.001) and diffuse (P = 0.002) atherosclerosis and lower 10-year cardiovascular risk. Hazard ratios were 0.10 (95% CI 0.01-0.70, P = 0.02) for ischemic heart disease and 0.24 (0.08-0.74, P = 0.013) for vascular death, per each added copy of 12Ala, respectively. CONCLUSIONS: Carriers of the 12Ala allele of PPARgamma have less widespread CAD and are considerably protected against 10-year (cardio)vascular morbidity and mortality. These long-term findings in patients with manifest CAD support an important role of PPARgamma in determining vascular ris

A Fisher-Rao Metric for curves using the information in edges

Two curves which are close together in an image are indistinguishable given a measurement, in that there is no compelling reason to associate the measurement with one curve rather than the other. This observation is made quantitative using the parametric version of the Fisher-Rao metric. A probability density function for a measurement conditional on a curve is constructed. The distance between two curves is then defined to be the Fisher-Rao distance between the two conditional pdfs. A tractable approximation to the Fisher-Rao metric is obtained for the case in which the measurements are compound in that they consist of a point x and an angle α which specifies the direction of an edge at x. If the curves are circles or straight lines, then the approximating metric is generalized to take account of inlying and outlying measurements. An estimate is made of the number of measurements required for the accurate location of a circle in the presence of outliers. A Bayesian algorithm for circle detection is defined. The prior density for the algorithm is obtained from the Fisher-Rao metric. The algorithm is tested on images from the CASIA Iris Interval database

The IL-1-Like Cytokine IL-33 Is Constitutively Expressed in the Nucleus of Endothelial Cells and Epithelial Cells In Vivo: A Novel ‘Alarmin’?

BACKGROUND: Interleukin-33 (IL-33) is an IL-1-like cytokine ligand for the IL-1 receptor-related protein ST2, that activates mast cells and Th2 lymphocytes, and induces production of Th2-associated cytokines in vivo. We initially discovered IL-33 as a nuclear factor (NF-HEV) abundantly expressed in high endothelial venules from lymphoid organs, that associates with chromatin and exhibits transcriptional regulatory properties. This suggested that, similarly to IL-1alpha and chromatin-associated cytokine HMGB1, IL-33 may act as both a cytokine and a nuclear factor. Although the activity of recombinant IL-33 has been well characterized, little is known yet about the expression pattern of endogenous IL-33 in vivo. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that IL-33 is constitutively and abundantly expressed in normal human tissues. Using a combination of human tissue microarrays and IL-33 monoclonal and polyclonal antibodies, we found that IL-33 is a novel nuclear marker of the endothelium widely expressed along the vascular tree. We observed abundant nuclear expression of IL-33 in endothelial cells from both large and small blood vessels in most normal human tissues, as well as in human tumors. In addition to endothelium, we also found constitutive nuclear expression of IL-33 in fibroblastic reticular cells of lymphoid tissues, and epithelial cells of tissues exposed to the environment, including skin keratinocytes and epithelial cells of the stomach, tonsillar crypts and salivary glands. CONCLUSIONS/SIGNIFICANCE: Together, our results indicate that, unlike inducible cytokines, IL-33 is constitutively expressed in normal human tissues. In addition, they reveal that endothelial cells and epithelial cells constitute major sources of IL-33 in vivo. Based on these findings, we speculate that IL-33 may function, similarly to the prototype 'alarmin' HMGB1, as an endogenous 'danger' signal to alert the immune system after endothelial or epithelial cell damage during trauma or infection

The Mixed-Lineage Kinase DLK Is a Key Regulator of 3T3-L1 Adipocyte Differentiation

The mixed-lineage kinase (MLK) family member DLK has been proposed to serve as a regulator of differentiation in various cell types; however, its role in adipogenesis has not been investigated. In this study, we used the 3T3-L1 preadipocyte cell line as a model to examine the function of DLK in adipocyte differentiation.Immunoblot analyses and kinase assays performed on 3T3-L1 cells showed that the expression and activity of DLK substantially increase as differentiation occurs. Interestingly, DLK appears crucial for differentiation since its depletion by RNA interference impairs lipid accumulation as well as expression of the master regulators of adipogenesis C/EBPalpha and PPARgamma2 at both the mRNA and protein levels. In contrast, neither the expression nor the DNA binding activity of C/EBPbeta, an activator for C/EBPalpha and PPARgamma, is affected by DLK loss.Taken together, these results suggest that DLK is important for expression of mature adipocyte markers and that its action most likely takes place via regulation of C/EBPbeta transcriptional activity and/or initiation of C/EBPalpha and PPARgamma2 gene transcription

Intracellular Function of Interleukin-1 Receptor Antagonist in Ischemic Cardiomyocytes

Background: Loss of cardiac myocytes due to apoptosis is a relevant feature of ischemic heart disease. It has been described in infarct and peri-infarct regions of the myocardium in coronary syndromes and in ischemia-linked heart remodeling. Previous studies have provided protection against ischemia-induced cardiomyocyte apoptosis by the anti-inflammatory cytokine interleukin-1 receptor-antagonist (IL-1Ra). Mitochondria triggering of caspases plays a central role in ischemia-induced apoptosis. We examined the production of IL-1Ra in the ischemic heart and, based on dual intra/extracellular function of some other interleukins, we hypothesized that IL-1Ra may also directly inhibit mitochondria-activated caspases and cardiomyocyte apoptosis. Methodology/Principal Findings: Synthesis of IL-1Ra was evidenced in the hearts explanted from patients with ischemic heart disease. In the mouse ischemic heart and in a mouse cardiomyocyte cell line exposed to long-lasting hypoxia, IL-1Ra bound and inhibited mitochondria-activated caspases, whereas inhibition of caspase activation was not observed in the heart of mice lacking IL-1Ra (Il-1ra−/−) or in siRNA to IL-1Ra-interfered cells. An impressive 6-fold increase of hypoxia-induced apoptosis was observed in cells lacking IL-1Ra. IL-1Ra down-regulated cells were not protected against caspase activation and apoptosis by knocking down of the IL-1 receptor, confirming the intracellular, receptor-independent, anti-apoptotic function of IL-1Ra. Notably, the inhibitory effect of IL-1Ra was not influenced by enduring ischemic conditions in which previously described physiologic inhibitors of apoptosis are neutralized. Conclusions/Significance: These observations point to intracellular IL-1Ra as a critical mechanism of the cell self-protection against ischemia-induced apoptosis and suggest that this cytokine plays an important role in the remodeling of heart by promoting survival of cardiomyocytes in the ischemic regions

IL-33 Is Produced by Mast Cells and Regulates IgE-Dependent Inflammation

Background: IL-33 is a recently characterized IL-1 family cytokine and found to be expressed in inflammatory diseases, including severe asthma and inflammatory bowl disease. Recombinant IL-33 has been shown to enhance Th2-associated immune responses and potently increase mast cell proliferation and cytokine production. While IL-33 is constitutively expressed in endothelial and epithelial cells, where it may function as a transcriptional regulator, cellular sources of IL-33 and its role in inflammation remain unclear. Methodology/Principal Findings: Here, we identify mast cells as IL-33 producing cells. IgE/antigen activation of bone marrow-derived mast cells or a murine mast cell line (MC/9) significantly enhanced IL-33. Conversely, recombinant IL-33 directly activated mast cells to produce several cytokines including IL-4, IL-5 and IL-6 but not IL-33. We show that expression of IL-33 in response to IgE-activation required calcium and that ionomycin was sufficient to induce IL-33. In vivo, peritoneal mast cells expressed IL-33 and IL-33 levels were significantly lower within the skin of mast cell deficient mice, compared to littermate controls. Local activation of mast cells promotes edema, followed by the recruitment of inflammatory cells. We demonstrate using passive cutaneous anaphylaxis, a mast cell-dependent model, that deficiency in ST2 or antibody blockage of ST2 or IL-33 ablated the late phase inflammatory response but that the immediate phase response was unaffected. IL-33 levels in the skin were significantly elevated only during the late phase

Identification of tissue-specific cell death using methylation patterns of circulating DNA

Minimally invasive detection of cell death could prove an invaluable resource in many physiologic and pathologic situations. Cell-free circulating DNA (cfDNA) released from dying cells is emerging as a diagnostic tool for monitoring cancer dynamics and graft failure. However, existing methods rely on differences in DNA sequences in source tissues, so that cell death cannot be identified in tissues with a normal genome. We developed a method of detecting tissue-specific cell death in humans based on tissue-specific methylation patterns in cfDNA. We interrogated tissue-specific methylome databases to identify cell type-specific DNA methylation signatures and developed a method to detect these signatures in mixed DNA samples. We isolated cfDNA from plasma or serum of donors, treated the cfDNA with bisulfite, PCR-amplified the cfDNA, and sequenced it to quantify cfDNA carrying the methylation markers of the cell type of interest. Pancreatic β-cell DNA was identified in the circulation of patients with recently diagnosed type-1 diabetes and islet-graft recipients; oligodendrocyte DNA was identified in patients with relapsing multiple sclerosis; neuronal/glial DNA was identified in patients after traumatic brain injury or cardiac arrest; and exocrine pancreas DNA was identified in patients with pancreatic cancer or pancreatitis. This proof-of-concept study demonstrates that the tissue origins of cfDNA and thus the rate of death of specific cell types can be determined in humans. The approach can be adapted to identify cfDNA derived from any cell type in the body, offering a minimally invasive window for diagnosing and monitoring a broad spectrum of human pathologies as well as providing a better understanding of normal tissue dynamics