Comparison of membrane structure, osmotic fragility, and morphology of multiple sclerosis and normal erythrocytes

Quantitative phase imaging of erythrocyte in epilepsy patients

The present study focuses on the quantitative phase imaging of erythrocytes with the aim to compare the morphological differences between epilepsy patients under antiepileptic treatment, who have no other disease which may affect the erythrocyte morphology, and the healthy control group. The white light diffraction phase microscopy (WDPM) has been used to obtain the interferogram of the erythrocyte surfaces. The continuous wavelet transform with Paul wavelet has been chosen to calculate the surface profiles from this interferogram image. For the determination of alteration in morphology, besides WDPM, erythrocyte surfaces have been investigated by light microscope and scanning electron microscope. In this way, it has been possible to see the difference in terms of precision and implementation between the most commonly used methods with regard to the quantitative phase imaging. Erythrocytes from all the samples have been examined and displayed in both two- and three-dimensional way. We have observed that erythrocytes of patients with effective antiepileptic blood levels were more affected in morphology than healthy subjects. When we compared the erythrocyte morphological changes of patients who received monotherapy or polytherapy, no difference was observed. In conclusion, antiepileptic drugs (AEDs) cause red blood cell (RBC) morphological changes and a combined usage of WDPM with Paul wavelet and light microscopy methods are very convenient for studying the erythrocyte morphologies on multiple patients.

Iron accumulation in the choroid plexus, ependymal cells and CNS parenchyma in a rat strain with low-grade haemolysis of fragile macrocytic red blood cells

Iron accumulation in the CNS is associated with many neurological diseases via amplification of inflammation and neurodegeneration. However, experimental studies on iron overload are challenging, since rodents hardly accumulate brain iron in contrast to humans. Here, we studied LEWzizi rats, which present with elevated CNS iron loads, aiming to characterise choroid plexus, ependymal, CSF and CNS parenchymal iron loads in conjunction with altered blood iron parameters and, thus, signifying non‐classical entry sites for iron into the CNS. Non‐haem iron in formalin‐fixed paraffin‐embedded tissue was detected via DAB‐enhanced Turnbull Blue stainings. CSF iron levels were determined via atomic absorption spectroscopy. Ferroportin and aquaporin‐1 expression was visualised using immunohistochemistry. The analysis of red blood cell indices and serum/plasma parameters was based on automated measurements; the fragility of red blood cells was manually determined by the osmotic challenge. Compared with wild‐type animals, LEWzizi rats showed strongly increased iron accumulation in choroid plexus epithelial cells as well as in ependymal cells of the ventricle lining. Concurrently, red blood cell macrocytosis, low‐grade haemolysis and significant haemoglobin liberation from red blood cells were apparent in the peripheral blood of LEWzizi rats. Interestingly, elevated iron accumulation was also evident in kidney proximal tubules, which share similarities with the blood–CSF barrier. Our data underscore the importance of iron gateways into the CNS other than the classical route across microvessels in the CNS parenchyma. Our findings of pronounced choroid plexus iron overload in conjunction with peripheral iron overload and increased RBC fragility in LEWzizi rats may be seminal for future studies of human diseases, in which similar constellations are found.

Free serum haemoglobin is associated with brain atrophy in secondary progressive multiple sclerosis

Background A major cause of disability in secondary progressive multiple sclerosis (SPMS) is progressive brain atrophy, whose pathogenesis is not fully understood. The objective of this study was to identify protein biomarkers of brain atrophy in SPMS. Methods We used surface-enhanced laser desorption-ionization time-of-flight mass spectrometry to carry out an unbiased search for serum proteins whose concentration correlated with the rate of brain atrophy, measured by serial MRI scans over a 2-year period in a well-characterized cohort of 140 patients with SPMS. Protein species were identified by liquid chromatography-electrospray ionization tandem mass spectrometry. Results There was a significant (p<0.004) correlation between the rate of brain atrophy and a rise in the concentration of proteins at 15.1 kDa and 15.9 kDa in the serum. Tandem mass spectrometry identified these proteins as alpha-haemoglobin and beta-haemoglobin, respectively.  The abnormal concentration of free serum haemoglobin was confirmed by ELISA (p<0.001). The serum lactate dehydrogenase activity was also highly significantly raised (p<10^-12) in patients with secondary progressive multiple sclerosis. Conclusions An underlying low-grade chronic intravascular haemolysis is a potential source of the iron whose deposition along blood vessels in multiple sclerosis plaques contributes to the neurodegeneration and consequent brain atrophy seen in progressive disease. Chelators of free serum iron will be ineffective in preventing this neurodegeneration, because the iron (Fe²⁺) is chelated by haemoglobin.

Free serum haemoglobin is associated with brain atrophy in secondary progressive multiple sclerosis

Background A major cause of disability in secondary progressive multiple sclerosis (SPMS) is progressive brain atrophy, whose pathogenesis is not fully understood. The objective of this study was to identify protein biomarkers of brain atrophy in SPMS. Methods We used surface-enhanced laser desorption-ionization time-of-flight mass spectrometry to carry out an unbiased search for serum proteins whose concentration correlated with the rate of brain atrophy, measured by serial MRI scans over a 2-year period in a well-characterized cohort of 140 patients with SPMS. Protein species were identified by liquid chromatography-electrospray ionization tandem mass spectrometry. Results There was a significant (p<0.004) correlation between the rate of brain atrophy and a rise in the concentration of proteins at 15.1 kDa and 15.9 kDa in the serum. Tandem mass spectrometry identified these proteins as alpha-haemoglobin and beta-haemoglobin, respectively.  The abnormal concentration of free serum haemoglobin was confirmed by ELISA (p<0.001). The serum lactate dehydrogenase activity was also highly significantly raised (p<10^-12) in patients with secondary progressive multiple sclerosis. Conclusions An underlying low-grade chronic intravascular haemolysis is a potential source of the iron whose deposition along blood vessels in multiple sclerosis plaques contributes to the neurodegeneration and consequent brain atrophy seen in progressive disease. Chelators of free serum iron will be ineffective in preventing this neurodegeneration, because the iron (Fe²⁺) is chelated by haemoglobin.

Red blood cell membrane fluidity in the etiology of multiple sclerosis

Organisms adjust the order, or fluidity, of their cellular membranes in response to changes in their physiochemical environment by adjusting the lipid composition of their membranes. We investigated membrane fluidity using the phospholipid, fatty acid and cholesterol content of red blood cells (RBCs) from multiple sclerosis (MS) patients and correlated this with C-reactive protein (CRP) as well as with the severity of neurological outcome as measured by the Kurtzke Expanded Disability Status Scale (EDSS) and its Functional System Scores. The study group consisted of 31 patients with MS and 30 healthy control subjects. Phospholipids were determined using a colorimetric assay, fatty acids by gas chromatography, cholesterol by an enzymatic assay and CRP by a Beckman nephelometer. Cell membrane fluidity was calculated according to previously established formulae. RBC membrane fluidity as measured by the saturated to polyunsaturated fatty acid ratio was higher in patients than in controls (P = 0.04). The phosphatidylethanolamine saturated to polyunsaturated fatty acid ratio showed highly significant positive correlations with the EDSS and CRP < 5 microg/ml. CRP showed significant inverse correlations with the saturated nature but positive correlations with the ordered-crystalline-phase to liquid-crystalline-phase lipid ratio. In this study we show that membrane fluidity as measured by the relationship between membrane fatty acids, phospholipids and cholesterol is closely interrelated with inflammation and disease outcome in patients with MS. In conclusion, our findings suggest that the membrane lipid composition of patients with MS and, consequently, membrane fluidity are altered, which seems to be influenced by the inflammatory status.

Lipoperoxides as an index of free radical activity in bone marrow transplant recipients. Preliminary observations

It has been previously demonstrated that the conditioning therapy given to bone marrow transplant (BMT) recipients creates a high oxidant stress, resulting in a measured reduction in antioxidants, such as glutathione peroxidase (GSH-Px), vitamin E, and cell peroxide fragilities. As part of a current intervention trial of antioxidant therapy in BMT recipients, plasma thiobarbituric acid reactive substances (TBARS) were measured to assess peroxidation and free radical activity. Measurements were performed before and after conditioning therapy, and then at weekly intervals for a period of 6 wk after transplantation in 20 patients (10 controls and 10 antioxidant therapy [AOT] recipients). The TBARS results were compared with concurrent measurements of more specific elements of the antioxidant pathways, such as red blood cell glutathione peroxidase (RBC-GSH-Px), plasma vitamin C, and serum vitamin E. In all cases, TBARS concentration was significantly increased after conditioning compared with baseline levels (p < 0.001), an increase that correlated inversely with RBC-GSH-Px (r = -0.81; p < 0.01). The TBARS concentration fell gradually after conditioning in all patients. The fall in the AOT group was more rapid than in the control group, and it paralleled the gradual return toward normal levels of the other antioxidants. The change in TBARS concentration occurred faster than changes in other indices, suggesting that TBARS might be a better index of overall free radical activity. Although the patient numbers are small, there is some evidence to suggest that MDA may act as a prognostic marker.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocyte fatty acids in multiple sclerosis

Analysis of the fatty acids in the erythrocyte lipid of multiple sclerosis patients in Italy gave no indication of any difference in composition compared with that of a healthy control group. Supplementation of the diet of another group of similar patients with polyunsaturated fatty acids led to increases in the erythrocyte levels of linoleate and docosahexaenoate, with concomitant falls in oleate and elaidate. Levels of fatty acids such as lignocerate and nervonate that are found predominantly in sphingomyelin were similar in all 3 groups.

Indium-111 oxine labeled erythrocytes: cellular distribution and efflux kinetics of the label

Indium-111 oxine label erythrocytes are useful in scintigraphic studies of splenic function because of the high yield of gamma-photons [172(90%) and 247(94%) keV] of indium-111. However, the effects of indium-111 oxine on the structural and functional integrity of erythrocytes which might influence their reticulo-endothelial (RE) sequestration are unknown. We examined the morphology of human and rat indium-111 labeled erythrocytes by SEM, the distribution of the label within the cell by analysis of the membrane and cytosol (hemoglobin solution) and the kinetics of efflux of indium-111 from erythrocytes incubated at 37 degrees C in plasma or physiological buffer. Indium-111 oxine labeled red cells retain their discocytic morphology and the cell indices, and density characteristics on phthalate ester are similar to those of the control cells. The efficiency of labeling may be as high as 97%. Human or rat erythrocyte membranes retain 33 and 41% of indium-111, and the cytosol contains 67 and 59%, respectively. About 98% of the indium-111 is bound to the membrane proteins and 1% to the lipid bilayer. Efflux of indium-111 from cells in autologous plasma showed a multiphasic release resulting in about 4-5% release of the label in 2 h and 11.5% in 20 h. Cells in PBS showed 1-5% release of the label during the incubation period. These findings suggest that indium-111 oxine labeling of erythrocytes does not grossly alter the structural and deformability integrity of the cells to induce selective RE sequestration, unless the cells have been damaged prior to or during the labeling procedure, or the spleen is hyperactive.

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.

Red cell and hemorheological changes in multiple sclerosis

Blood rheology in multiple sclerosis (MS) was investigated in 15 subjects with varying degrees of locomotor difficulties who were members of the local MS Society. Control data were obtained from blood samples from 25 male and 25 female normal blood donors. Whole blood viscosity was measured and blood filterability was assessed. Six MS females provided blood samples for scanning electron microscopy. Erythrocyte membrane fatty acids and phospholipids were assayed. Whole blood viscosity in MS females was higher than controls at 3 of 4 shear rates (p less than 0.001) but in MS males blood viscosity was higher only at shear rate of 1.0 s-1 (p less than 0.05). MS erythrocyte filtration rates were significantly lower than controls (p less than 0.001). Leucocyte counts in MS were greater than controls both in males (p less than 0.01) and females (p less than 0.001). MS erythrocyte morphology was greatly different from controls (p less than 0.0001) and erythrocyte membranes contained less sphingomyelin than controls (p less than 0.01) but more phosphatidylinositol plus phosphatidylserine (p less than 0.02). We conclude that, because our findings indicate an identifiable and potentially correctable abnormality, it is possible to envisage an inhibition of the progressive nature of MS, with the hope of a better prognosis for patients.

Lipid peroxidation products and antioxidant proteins in plasma and cerebrospinal fluid from multiple sclerosis patients

Lipid peroxidation (LPx) products were measured as thiobarbituric acid-reactive substances (TS) and lipid-soluble fluorescent pigments (FP) in both plasma and CSF from MS patients and controls. Although no significant changes were found in MS plasma, we report here for the first time increases in both TS and FP in MS CSF (p less than 0.05 and p less than 0.01, respectively, compared with patients with other neurological diseases), indicating that increased LPx in CNS may be a feature of MS. Levels of transferrin were normal but caeruloplasmin (CP), a major antioxidant plasma protein, was significantly raised in MS patients (p less than 0.01) and this may represent an adaptive response to increased oxidative challenge. Neither of these proteins was detectable in CSF using radial immunodiffusion. There was no significant correlation between the severity or duration of the disease nor the period since the last relapse and either LPx products or CP suggesting that the changes observed in this work are not simply the direct result of demyelination and tissue damage.

Erythrocyte antioxidant enzymes in multiple sclerosis and the effect of hyperbaric oxygen

The activities of catalase, glutathione peroxidase, and glutathione reductase, were not significantly different from normal whereas that of superoxide dismutase was decreased (P less than 0.05) in erythrocytes from patients with multiple sclerosis. Assay of the lipid peroxidation product, malondialdehyde, after incubation of erythrocytes with 10 mM H2O2 under carefully controlled conditions (peroxide stress test) demonstrated that MS erythrocytes are significantly (P less than 0.001) less susceptible to H2O2-induced lipid peroxidation in vitro. This finding suggests that the level of an endogenous antioxidant, possibly vitamin E, may be elevated in MS red cells. After treatment with hyperbaric O2, the activity of MS erythrocyte catalase is significantly (P less than 0.01) elevated by 2-6-fold.

Erythrocyte membrane glycerophospholipid organization is normal in multiple sclerosis

The phospholipid composition of erythrocyte membranes from patients with multiple sclerosis (MS) was found to be normal, in agreement with previous reports. The transbilayer asymmetry of the glycerophospholipids in MS red cells was probed using bee venom phospholipase A2 and was also found not to be significantly different from normal. Abnormal membrane glycerophospholipid organisation is therefore not involved in the increased red cell size, osmotic fragility, and electrophoretic mobility associated with MS.