Heparin oligosaccharides bind L- and P-selectin and inhibit acute inflammation

Initial attachment of leukocytes to the vessel wall at sites of inflammation is supported by a family of carbohydrate-binding adhesion molecules called the selectins. Selectin ligands include sialyl-Lewis x (sLex, Neu5Ac alpha 2-3Gal beta 1-4[Fuc alpha 1-3]GlcNAc--) and related structures. We report here that defined heparin oligosaccharides interact with the selectins. Heparin chains containing four or more monosaccharide residues inhibited the function of L- and P-selectin, but not E-selectin, in vitro. In a competition enzyme-linked immunosorbent assay measuring inhibition of solution-phase selectin-Ig fusion proteins (selectin-Ig) binding to immobilized bovine serum albumin-sLex neoglycoprotein, a heparin-derived tetrasaccharide mixture inhibited 50% of L- and P-selectin-Ig binding (IC50) at 200 +/- 40 mumol/L and 850 +/- 110 mumol/L, respectively. A single hexasulfated tetrasaccharide (delta UA2S alpha 1-4GlcNS6S alpha 1-4IdoA2S alpha 1- 4GlcNS6S) was particularly active against L- and P-selectin-Ig (IC50 = 46 +/- 5 mumol/L and 341 +/- 24 mumol/L). By comparison, the tetrasaccharide sLex was not inhibitory at concentrations up to 1 mmol/L. In cell adhesion assays, heparin tetrasaccharides reduced binding of neutrophils to COS cells expressing P-selectin but not to COS cells expressing E-selectin. They also blocked colon cancer cell adhesion to L- and P-selectin but not E-selectin. In a model of acute inflammation, intravenously administered heparin tetrasaccharides diminished influx of neutrophils into the peritoneal cavities of thioglycollate-treated mice. We conclude that heparin oligosaccharides, including non-anticoagulant tetrasaccharides, are effective L- and P- selectin inhibitors in vitro and have anti-inflammatory activity in vivo.     

The activation of the contact phase of coagulation by physiologic surfaces in plasma: the effect of large negatively charged liposomal vesicles

The endogenous, negatively charged surface that induces activation of the contact coagulation factors was investigated in plasmas taken from women in late pregnancy and control subjects of child-bearing age. The plasmas from the two groups of subjects were incubated at 4 degrees C for 24 hours either in plastic or in glass tubes and the factor VII coagulant activity (VIIc) was assayed in the treated plasmas. The activation of factor VII under these conditions involves the generation of enzymes derived from factor XII (XIIa). The contact surface is rate- limiting for the activation of factor VII in the plasmas in both groups of subjects and can be supplemented by large multilamellar liposomal vesicles carrying the appropriate density of negative charge. The size of these vesicles is within the range of sizes of the large lipoprotein particles (chylomicrons, very low and intermediate-density lipoproteins). The relationship between the density of negative charge on the liposomal vesicles and VIIc was similar in the late pregnancy and the control plasmas incubated in plastic tubes. At a saturating density of negative charge the observed relative VIIc was similar in both sets of plasmas. The incubation of late pregnancy or control plasma in plastic tubes in the presence of sodium stearate caused VIIc to increase with increasing concentration of the added fatty acid. These results suggest that large lipoprotein particles carrying the appropriate free fatty acid at a sufficient density of negative charge could provide the contact surface that induces the generation of factor XIIa and the subsequent activation of factor VII. Moreover, plasmas from women in late pregnancy have a higher concentration of potential surface and a higher density of negative charge than the plasmas from nonpregnant women.     

Production of cytokines by bone marrow cells obtained from patients with multiple myeloma

Previous work with continuously cultured multiple myeloma lines suggested that cytokine production by tumor cells may mediate some of the medical complications of this disease. To further investigate this issue, we assayed freshly obtained bone marrow (BM) cells from myeloma patients for the in vitro production of cytokines and the presence of cytokine RNA. Production of cytokine protein was assessed by bioassays with the aid of specific neutralizing anticytokine antibodies. These assays detected interleukin-1 (IL-1) and tumor necrosis factor (TNF) secretion by myeloma BM cells, which was significantly greater than secretion from similarly processed BM cells of control individuals. In contrast, lymphotoxin and interleukin-2 (IL-2) production could not be detected. The levels of IL-1 and TNF produced in vitro peaked at 24 hours of culture and correlated with stage and the presence (or absence) of extensive osteolytic bone disease. Northern blot analysis demonstrated the presence of IL-1 beta and TNF RNA in uncultured myeloma BM cells but no detectable IL-1 alpha or lymphotoxin RNA. In addition, the amount of cytokine RNA correlated with protein production, being significantly greater in patients' BM cells than in control marrow. These data suggest a role for IL-1 beta and/or TNF in the pathophysiology of multiple myeloma and argue against a role for lymphotoxin or IL-2.     

Association of vitiligo with HLA-A2: a meta-analysis

BACKGROUND: Linkage and association studies suggest that the human leucocyte antigen (HLA) region may be involved in the genetic susceptibility of vitiligo. HLA-A2 has been reported to be associated with vitiligo in some, but not all, studies. OBJECTIVE: To identify sources of the heterogeneity among studies and to quantify effect estimates, we examined the association of HLA-A2 with vitiligo in a meta-analysis of all observational studies comparing the frequencies of HLA-A2 between vitiligo individuals and controls during 1966-2005. METHODS: The summary odds ratio (OR) was calculated by using a fixed- or a random-effects model. Meta-regression analysis was undertaken to investigate the effects of study characteristics on the pooled OR. RESULTS: Eleven case-controlled studies fulfilled our inclusion criteria. The studies identified a total of 777 patients and 4820 controls. Meta-analysis showed a significantly increased frequency of HLA-A2 in vitiligo among cases [OR = 2.07, 95% confidence interval (CI) 1.67-2.58]. Heterogeneity was explained by the quality of the study and the ethnic background of the participants. Meta-regression analysis further showed that the percentage of familial vitiligo among the subjects had a significant effect on the pooled OR (P = 0.008). No study had a significant effect on the pooled OR and no publication bias presented in the studies analysed (P = 0.688). CONCLUSION: These findings strongly suggest an association between HLA-A2 and vitiligo.     

X-linked hypophosphatemia in adults: prevalence of skeletal radiographic and scintigraphic features

The radiologic studies of 38 essentially untreated adults with X-linked hypophosphatemia (XLH) were reviewed to determine the prevalence of radiologic features, to compare the findings in men and in women, and to elucidate the natural history of the disease by comparing the findings in young, intermediate-age, and older patients. Bone-reinforcement lines were common, but no characteristic mineral mass alteration was established. Looser zones were more prevalent in older subjects. Osteoarthritis was common, occurring in the ankles, knees, feet, sacroiliac joints, and wrists. Enthesopathy was infrequent in the younger group but was present in every member of the intermediate and older groups and was often accompanied by extra ossicles. Curvatures of the lower-extremity long bones were common in all age groups. Three new skeletal alterations in XLH were found to be common: flaring of the iliac wings, trapezoidal distal femoral condyles, and alterations in talar morphology, including shortening of the talar neck and flattening of the talar dome. Technetium-99m methylene diphosphonate scintigrams of 17 subjects were often abnormal, depicting bowing deformity and focal tracer accumulation in diaphyseal cortices and in periarticular and extraarticular regions. The mean metabolic index was moderately elevated (4.0). Both radiographic and scintigraphic findings were more severe in men, consistent with hemizygosity. The natural history of untreated XLH in both sexes is characterized by the development of a variety of age-related skeletal abnormalities during adulthood.