Platelet behaviour and plasma phospholipids in multiple sclerosis

Identification of prognostic factors and construction of a nomogram for patients with relapse/refractory adult-onset Still's disease

OBJECTIVES

This study aimed to identify the risk factors for relapse/refractory adult-onset Still's disease (AOSD) and to construct and validate a prognostic nomogram for predicting the individual risk of relapse/refractory disease.

METHOD

A total of 174 patients were included in our study. Univariate and multivariate logistic regression analyses were used to identify relapse/refractory-associated factors, which were used to construct nomograms. Receiver operating characteristic (ROC) curve analysis, calibration curves, and decision curve analysis (DCA) were used to assess the predictive ability of the nomograms.

RESULTS

Univariate and multivariate logistic analyses showed that age, fever, disease duration, platelet count, serum ferritin level, and erythrocyte sedimentation rate were independent unfavourable factors for relapse/refractory AOSD (p < 0.05). We constructed a 6-factor nomogram based on univariate and multivariate logistic analyses. ROC analysis indicated that the area under the curve of the 6-factor nomogram in the training set and test set was 0.765 and 0.714, respectively. In addition, the calibration curves showed excellent prediction accuracy, and DCA showed superior net benefit in the 6-factor nomograms. Moreover, we evaluated the predictive effectiveness of our nomogram in females and young adults. The results showed that our 6-factor nomogram has the same predictive ability in both subgroups.

CONCLUSIONS

Novel nomograms based on clinical characteristics were developed and may be applied to help predict the individual risk of poor prognosis of patients. Key Points • Logistic regression was used to identify risk factors for relapse/refractory adult-onset Still's disease. • We then constructed a nomogram for predicting disease risk. • ROC analysis, calibration curves, and DCA all showed that the nomogram exerted good prediction ability in both the training set and test set. • The nomogram has the same predictive ability in both female and young adult subgroups.

Platelets as Mediators of Neuroinflammation and Thrombosis

Beyond platelets function in hemostasis, there is emerging evidence to suggest that platelets contribute crucially to inflammation and immune responses. Therefore, considering the detrimental role of inflammatory conditions in severe neurological disorders such as multiple sclerosis or stroke, this review outlines platelets involvement in neuroinflammation. For this, distinct mechanisms of platelet-mediated thrombosis and inflammation are portrayed, focusing on the interaction of platelet receptors with other immune cells as well as brain endothelial cells. Furthermore, we draw attention to the intimate interplay between platelets and the complement system as well as between platelets and plasmatic coagulation factors in the course of neuroinflammation. Following the thorough exposition of preclinical approaches which aim at ameliorating disease severity after inducing experimental autoimmune encephalomyelitis (a counterpart of multiple sclerosis in mice) or brain ischemia-reperfusion injury, the clinical relevance of platelet-mediated neuroinflammation is addressed. Thus, current as well as future propitious translational and clinical strategies for the treatment of neuro-inflammatory diseases by affecting platelet function are illustrated, emphasizing that targeting platelet-mediated neuroinflammation could become an efficient adjunct therapy to mitigate disease severity of multiple sclerosis or stroke associated brain injury.

A prolonged antibiotic protocol to treat persistent Chlamydophila pneumoniae infection improves the extracranial venous circulation in multiple sclerosis

Objective Chronic cerebrospinal venous insufficiency (CCSVI) is a condition associated with multiple sclerosis (MS). One mechanism that has been proposed is that the venous obstructions found in MS are due to a chronic persistent venulitis caused by the intra-cellular bacterial parasite, Chlamydophila pneumoniae (Cpn). The objective of the current study is to determine the effect of a combined antibiotic protocol (CAP) on the venous flow in MS patients as measured by a quantitative duplex ultrasound examination (QDUS). Method A non-randomised before-after cohort study was conducted to investigate differences in blood flow volumes pre and 6-months post antibiotic treatment for Cpn infection. Flow volume data were measured by QDUS across affected and unaffected sides from multiple veins segments, including internal jugular vein (IJV) segments J2 and J3, and vertebral vein (VV), as well as global arterial blood flow (GABF). Results 91 patients were included in the study. 64 (70%) were found to have positive Cpn serology. There was a statistically significant post-treatment difference seen for the affected side of Cpn infected patients (mean difference = 56 mL/min, p = 0.02). There was a non-significant increase seen for the affected side of uninfected patients (mean difference = 23 mL/min, p = 0.2). The difference in these effects (34 mL/min) was not statistically significant ( p = 0.3). The mean flow rate decreased in the unaffected side for both infected (-27 mL/min, p = 0.5) and uninfected patients (-69 mL/min, p = 0.01). There was a statistically significant post-treatment increase in GABF for the infected patients (mean difference = 90 mL/min, p = 0.02) and a difference of 76 mL/min for non-infected patients ( p = 0.01). Conclusion A CAP appears to improve the extra-cranial circulation in patients diagnosed with MS. This effect is statistically significant in patients with positive Cpn serology, although patients with negative Cpn serology also show some benefit, betraying a lack of specificity of this effect.

The Inflammatory Role of Platelets: Translational Insights from Experimental Studies of Autoimmune Disorders

Beyond their indispensable role in hemostasis, platelets have shown to affect the development of inflammatory disorders, as they have been epidemiologically and mechanistically linked to diseases featuring an inflammatory reaction in inflammatory diseases like multiple sclerosis, rheumatoid arthritis and inflammatory bowel disorders. The identification of novel molecular mechanisms linking inflammation and to platelets has highlighted them as new targets for therapeutic interventions. In particular, genetic and pharmacological studies have identified an important role for platelets in neuroinflammation. This review summarizes the main molecular links between platelets and inflammation, focusing on immune regulatory factors, receptors, cellular targets and signaling pathways by which they can amplify inflammatory reactions and that make them potential therapeutic targets.

Plasma Lipids and Lipoproteins in Friedreich's Ataxia and Familial Spastic Ataxia — Evidence for an Abnormal Composition of High Density Lipoproteins

A systematic study of plasma lipids and lipoproteins was carried out in II cases of Friedreich's ataxia and 6 cases of familial spastic ataxia (Charlevoix-Saguenay disease) using II healthy normolipidemic volunteers of comparable age and sex as controls. No differences were noted in the fatty acid profile of the total lipid fraction, in the total cholesterol and phospholipids or in the percentage distribution of the individual phospholipid classes. The triglycerides were significantly higher in Friedreich's ataxia, but remained within the normal range. Although no systematic abnormalities could be detected in the electrophoretic pattern of plasma lipoproteins or in the apolipoprotein profile on polyacrylamide gel electrophoresis, major differences were found in the high density lipoprotein (HDL) fraction. Their total amount was reduced and their composition was abnormal in both neurological diseases. In Friedreich patients, the relative proportion of cholesterol and triglycerides was increased while the relative protein content was greatly reduced. In Charlevoix disease, a similar abnormality was seen except for the excess of triglycerides. The proportion of phospholipids in HDL was the same in the three groups of patients. In addition, the low density lipoprotein (LDL) fraction was slightly reduced in both diseases. This anomaly of the HDL fraction could indicate that the HDL apolipoprotein moiety has a greater affinity for cholesterol and triglycerides in Friedreich's ataxia than its normal counterpart.

Membrane active plasma factor in multiple sclerosis: characterization and isolation by recycling isoelectric focusing

Recycling isoelectric focusing is a rapid, high resolution technique that has the capability of fractionating complex mixtures of proteins on a preparative scale on the basis of their isoelectric points (pIs). For this reason, it appeared to be an ideal tool to further characterize and isolate the surface active plasma component(s) which is abnormal in multiple sclerosis (MS). The normal control and the abnormal MS plasma components, or factors, proved to be stable under the conditions used in this technique, including deionization by electrodialysis, dialysis against distilled water, lyophilization and the presence of 3M urea and carrier distilled water, lyophilization and the presence of 3M urea and carrier ampholytes. The presence or absence of plasma factor activity was determined by incubating red blood cells in a test plasma, or plasma fraction, followed by the determination of the red blood cell electrophoretic mobility in the presence and absence of linoleic acid. Both the normal and MS factor had a pI of 4.0 +/- 0.1 under the conditions used. A high degree of purification was achieved and albumin was eliminated as a possible candidate for the factor(s).

A search for protein abnormalities in erythrocyte membranes and platelets from patients with multiple sclerosis using double-label two-dimensional electrophoresis

Proteins from erythrocyte membranes and whole platelets from patients with definite multiple sclerosis (MS) and normal subjects were compared using a double-label two-dimensional procedure. No consistent differences were found in the proteins adherent or intrinsic to erythrocyte membranes. The results of initial studies with platelets showed the absence of a group of three protein spots in the electrophoretic gels of the MS specimens. Further experiments suggested that these results were probably due to minor differences in the handling of the MS and normal specimens although the possibility of a difference in protease activity was not completely eliminated.

Response to platelet-activating factor of platelets from patients with multiple sclerosis

The response of Multiple Sclerosis (MS) and control platelets to different concentrations of platelet-activating factor was studied. At concentrations in the range 10(-7) to 10(-5)M, it was found that the MS platelets tended to aggregate fully at lower concentrations than was the case with control platelets. At a concentration of 10(-6)M, it was found that in 19 cases the MS platelets gave a full aggregation response whilst 4 cases showed biphasic but full aggregation, whereas at this concentration the control platelets showed full aggregation in only 2 cases, biphasic but less complete aggregation in 5 cases and reversible aggregation in 16 cases. In crossover studies, it could be shown that MS platelets resuspended in control platelet-poor plasma still showed enhanced aggregability and that the response of control platelets was unaffected by resuspension in MS platelet-poor plasma. Differences were also seen in susceptibility of platelets of MS and control subjects to inhibition by indomethacin, bromophenacyl bromide (a phospholipase inhibitor) and verapamil (a Ca2+ antagonist). It is suggested that the hyperaggregability of the MS platelets could reside in the platelets themselves, and may be associated with enhanced phospholipase activity.

Plasma lipids, blood coagulation and fibrinolysis in peripheral arterial disease

In a study relating platelet stickiness, plasma fibrinogen and fibrinolysis to fasting plasma lipids in patients with atherosclerosis of the lower limbs, a significant correlation has been observed between platelet stickiness and plasma phospholipid levels. The possible mechanisms are discussed. No other correlation is observed. Fasting levels of plasma fibrinogen were raised, while levels of plasminogen, and the degree of platelet stickiness in many cases were normal.