Adenoviral vectors do not induce, inhibit, or potentiate human platelet aggregation.

Adenoviruses are commonly used as vectors in human clinical gene therapy trials. High doses of intravenous adenovirus vectors have been associated with development of thrombocytopenia of undetermined origin. Viral internalization requires the presence cell surface integrins, alpha(v)beta(3) or alpha(v)beta(5), that can blind ligands with a arginine-glycine-aspartic acid (RGD) sequence. This sequence is found in the adenovirus penton base. Platelets express the alpha(v)beta(3) integrin and other integrins that bind the RGD sequence of ligands such as fibrinogen, laminin, vitronectin, and von Willebrand factor (vWF). Platelet aggregation is mediated, in part, by the binding of the RGD sequence of fibrinogen to a platelet surface integrin, glycoprotein IIb/IIIa (GP IIb/IIIa). We investigated whether adenovirus particles could interfere with or potentiate agonist-induced platelet aggregation. Incubation of platelet-rich plasma with adenovirus under stirred conditions did not promote spontaneous aggregation. The addition of physiological platelet agonists, ADP, collagen, or epinephrine, induced platelet aggregation. However, the presence of adenovirus in a wide range of concentrations did not inhibit or potentiate agonist-induced aggregation. These results suggest that the adenovirus-associated thrombocytopenia observed in vivo is independent of a direct effect of the virus on platelet aggregation.     

Reduction of scar formation in full-thickness wounds with topical celecoxib treatment

Adult wound repair occurs with an initial inflammatory response, reepithelialization, and the formation of a permanent scar. Although the inflammatory phase is often considered a necessity for successful adult wound healing, fetal healing studies have shown the ability to regenerate skin and to heal wounds in a scarless manner in the absence of inflammation. The cyclooxygenase-2 (COX-2) enzyme, a known mediator of inflammation, has been shown to contribute to a variety of inflammatory conditions and to the development of cancer in many organs. To examine the role of COX-2 in the wound healing process, incisional wounds were treated topically with the anti-inflammatory COX-2 inhibitor celecoxib. Acutely, celecoxib inhibited several parameters of inflammation in the wound site. This decrease in the early inflammatory phase of wound healing had a significant effect on later events in the wound healing process, namely a reduction in scar tissue formation, without disrupting reepithelialization or decreasing tensile strength. Our data suggest that in the absence of infection, adult wound healing is able to commence with decreased inflammation and that anti-inflammatory drugs may be used to improve the outcome of the repair process in the skin by limiting scar formation.     

Trabecular Shear Stresses Predict <Emphasis Type="Italic">In Vivo</Emphasis> Linear Microcrack Density but not Diffuse Damage in Human Vertebral Cancellous Bone

Linear microcracks and diffuse damage (staining over a broad region) are two types of microscopic damage known to occur in vivo in human vertebral trabecular bone. These damage types might be associated with vertebral failure. Using microcomputed tomography and finite element analysis for specimens of cancellous bone, we estimated the stresses in the trabeculae of human vertebral tissue for inferosuperior loading. Microdamage was quantified histologically. The density of in vivo linear microcracks was, but the diffuse damage area was not, related to the estimates of von Mises stress distribution in the tissue. In vivo linear microcrack density increased with increasing coefficient of variation of the trabecular von Mises stress and with increasing average trabecular von Mises stress generated per superoinferior apparent axial stress. Nonlinear increase in linear crack density, similar to the increase of the coefficient of variation of trabecular shear stresses, with decreasing bone stiffness and bone volume fraction suggests that damage may accumulate rather rapidly in diseases associated with low bone density due to the dramatic increase of shear stresses in the tissue. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8719Xx, 8759Ls, 8759Fm, 8710+e     

Meta-analysis of epigenome-wide association studies of carotid intima-media thickness

Common carotid intima-media thickness (cIMT) is an index of subclinical atherosclerosis that is associated with ischemic stroke and coronary artery disease (CAD). We undertook a cross-sectional epigenome-wide association study (EWAS) of measures of cIMT in 6400 individuals. Mendelian randomization analysis was applied to investigate the potential causal role of DNA methylation in the link between atherosclerotic cardiovascular risk factors and cIMT or clinical cardiovascular disease. The CpG site cg05575921 was associated with cIMT (beta?=??0.0264, p value?=?3.5?×?10^–8) in the discovery panel and was replicated in replication panel (beta?=??0.07, p value?=?0.005). This CpG is located at chr5:81649347 in the intron 3 of the aryl hydrocarbon receptor repressor gene (AHRR). Our results indicate that DNA methylation at cg05575921 might be in the pathway between smoking, cIMT and stroke. Moreover, in a region-based analysis, 34 differentially methylated regions (DMRs) were identified of which a DMR upstream of ALOX12 showed the strongest association with cIMT (p value?=?1.4?×?10^–13). In conclusion, our study suggests that DNA methylation may play a role in the link between cardiovascular risk factors, cIMT and clinical cardiovascular disease.

     

Antibodies to CD45 and other cell membrane antigens in systemic lupus erythematosus

Conclusions The multivalency of cold-reactive IgM anti-lymphocyte autoantibodies, together with the local density of reactive antigens on the cell surface, may confer a capacity for a variety of immunoregulatory and non-specific physiological roles in the immune system and in SLE and other autoimmune diseases. Targets of interest in this regard include CD45, ₂ microglobulin, and surface immunoglobulin. IgG anti-lymphocyte autoantibodies, while more difficult to study, also exhibit interesting specificities. However, whether any of the mechanisms by which anti-lymphocyte autoantibodies could alter cellular function actually obtain in vivo remains speculative. Essentially all of the data in this regard derive from experiments in which anti-lymphocyte autoantibody-containing SLE serum or plasma, or purified Ig fractions thereof, is combined with peripheral blood mononuclear cells in short-term culture in vitro. Thus, it is possible that anti-lymphocyte autoantibodies in SLE, rather than contributing to pathogenesis, reflect a physiological attempt by the immune system to restore homeostasis in the face of aggressive autoimmune stimulation.     

Effect of oral antidiabetic agents on plasma amylin level in patients with non-insulin-dependent diabetes mellitus (type 2).

The purpose of the study was the comparison of the effect of the oral therapy of non-insulin-dependent diabetes mellitus (NIDDM) with either a sulphonylurea or biguanide derivative on plasma amylin level. In 10 healthy individuals the fasting plasma amylin level was 1.56 +/- 0.27 pmol/l (mean +/- SEM) and 6 min after i.v. injection of 1 mg glucagon a fourfold increase was observed. In 10 patients with NIDDM receiving glibenclamide (CAS 10238-21-8) the fasting plasma amylin level was twofold higher than in healthy control (2.72 +/- 0.38 pmol/l; p < 0.025) but following glucagon administration it increased only twofold. In 15 patients treated with metformin (CAS 657-24-9) the fasting plasma amylin level was similar to that in healthy individuals (1.64 +/- 0.25 pmol/l), but after glucagon stimulation the increment of plasma amylin was minimal and the relevant mean value was significantly lower when compared with those in healthy individuals and with NIDDM patients treated with glibenclamide. In 10 untreated obese patients with newly diagnosed NIDDM the administration of glibenclamide (14 days) resulted in the increase of basal (2.47 +/- 0.23 and 3.16 +/- 0.29 pmol/l; p < 0.1), and glucagon stimulated (3.34 +/- 0.39 and 4.56 +/- 0.38; p < 0.05) plasma amylin concentrations, whereas other 10 patients receiving metformin showed a decrease in fasting plasma level of this peptide before (2.64 +/- 0.59 and 1.28 +/- 0.38 pmol/l; p < 0.1), and after glucagon injection (5.02 +/- 0.55 and 2.83 +/- 0.65 pmol/l; p < 0.02). With the respect to the trophic effect of amyloid deposits in the pancreatic islets and to a hypothetic effect of amylin increasing insulin resistance, the present results emphasize the particular usefulness of metformin in the pharmacological treatment of NIDDM. All contraindications and side effects of metformin should be taken into account before drug administration.