Changes in phospholipid composition of blood cell membranes (erythrocyte, platelet, and polymorphonuclear) in different types of diabetes--clinical and biological correlations

The Footprint of Type 1 Diabetes on Red Blood Cells: A Metabolomic and Lipidomic Study

The prevalence of diabetes type 1 (T1D) in the world populations is continuously growing. Although treatment methods are improving, the diagnostic is still symptom-based and sometimes far after onset of the disease. In this context, the aim of the study was the search of new biomarkers of the disease in red blood cells (RBCs), until now unexplored. The metabolomic and the lipidomic profile of RBCs from T1D patients and matched healthy controls was determined by NMR spectroscopy, and different multivariate discrimination models were built to select the metabolites and lipids that change most significantly. Relevant metabolites were further confirmed by univariate statistical analysis. Robust separation in the metabolomic and lipidomic profiles of RBCs from patients and controls was confirmed by orthogonal projection on latent structure discriminant analysis (OPLS-DA), random forest analysis, and significance analysis of metabolites (SAM). The main changes were detected in the levels of amino acids, organic acids, creatine and phosphocreatine, lipid change length, and choline derivatives, demonstrating changes in glycolysis, BCAA metabolism, and phospholipid metabolism. Our study proves that robust differences exist in the metabolic and lipidomic profile of RBCs from T1D patients, in comparison with matched healthy individuals. Some changes were similar to alterations found already in RBCs of T2D patients, but others seemed to be specific for type 1 diabetes. Thus, many of the metabolic differences found could be biomarker candidates for an earlier diagnosis or monitoring of patients with T1D.

Altered red blood cell deformability-A novel hypothesis for retinal microangiopathy in diabetic retinopathy

PURPOSE

Impaired red blood cell (RBC) deformability impedes tissue perfusion. This study aims to investigate RBC biomechanics in type 2 diabetes mellitus (DM) patients with different grades of diabetic retinopathy (DR) and to correlate RBC deformability with hematological and serum biochemical markers.

METHODS

This cross-sectional study included 86 type 2 DM patients (31 with no DR, 31 with non-proliferative DR [NPDR] and 24 with proliferative DR [PDR]) and 32 control subjects. RBC deformability was measured by a microfluidic cross-slot channel (elongation index, EI). Venous blood samples were taken for assessment of hematological and serum biochemical markers.

RESULTS

RBC deformability showed significant reduction in diabetic patients, being lowest in the PDR group, followed by NPDR and DM with no DR groups, and highest in control group (P = .018). RBC deformability was not affected by age or gender but showed significant associations with certain hematological and serum biochemical markers. In the regression analysis controlling for DM status, urea concentration and reticulocyte count were shown to be negatively associated with EI.

CONCLUSION

Impaired RBC deformability measured by a microfluidic cross-slot channel in DM patients with different grades of DR underscores the contribution of RBC rheological properties to the pathogenesis and progression of DM related microangiopathy.

Insight into erythrocyte phospholipid molecular flux in healthy humans and in patients with acute respiratory distress syndrome

Although the distribution of cellular membrane phospholipid composition is well characterised in human erythrocytes, in-vivo turnover and dynamic flux of phospholipids between plasma and erythrocytes in physiological and in particular during disease states are mostly unknown. Erythrocyte mass primarily consisted of lipids and phosphatidylcholine (PC) contributes to the significant proportion of phospholipid membrane composition. Esterified membrane PC can be utilised during pathological processes to generate pro and anti-inflammatory lipid mediators, which can contribute to the pathogenesis of acute respiratory distress syndrome (ARDS). In this study, utilising isotope labelling of choline and analytical methods with electrospray mass spectrometry (ESI-MS/MS), we characterised individual molecular composition and dynamic exchange of PC, sphingomyelins (SM) and lysophosphatidylcholines (LPC) between plasma and erythrocytes. In ARDS patients, there were significant alterations in PC molecular composition, coupled with a continuous loss of arachidonoyl-PC species over time. Infusion of methyl-D9-choline chloride resulted in enrichment of labelled choline into plasma PC and LPC via CDP-choline pathway with subsequent incorporation into erythrocyte PC. As expected, erythrocyte methyl-D9 PC enrichment is much slower than plasma. Patients had much faster and higher fractional enrichment of all PC and LPC molecules suggesting increased flux between plasma and erythrocytes. There was a particular pattern of incorporation, where the arachidonoyl-PC species achieved equilibrium with plasma rapidly and retained highest concentrations of enrichment compared to the other PC species. Increased enrichment of arachidonoyl-PC coupled with virtually no increase or depletion of its concentrations suggests the possibility of substrate donation for other cell types for the participation of eicosanoid biosynthesis during inflammatory conditions like ARDS. In summary, this study revealed an alerted pattern erythrocyte molecular phospholipid composition and flux in patients with acute respiratory distress syndrome and the pathological consequences of these changes needs further exploration.

[The study of the membrane-protective potential of the combination of 2-ethyl-6-methyl-3-hydroxypyridine-succinate and citicoline]

AIM

To assess the changes in the composition of plasma phospholipids in patients with chronic cerebrovascular disease treated with neuroprotectors 2-ethyl-6-methyl-3-hydroxypyridine succinate (neurox) and citicoline (neipilept), the natural metabolites involved in biochemical processes in the body, and their composition.

MATERIAL AND METHODS

The study included 40 patients, 18 men and 22 women, aged from 54 to 72 years, with chronic cerebrovascular disease at the decompensation stage complicated with the hypertensive crisis and/or arrhythmia.

RESULTS AND CONCLUSION

During extraction of phospholipids from blood cells, a significant decrease in the amount of total lipids was found to the end of treatment of patients who received neurox or neipilept or their combination. The study of quantitative composition of phospholipids showed no significant changes in patients treated with neurox, while the use of citicoline or combination of citicoline with 2-ethyl-6-methyl-3-hydroxypyridine succinate resulted in the increase of their total mass. There were no significant changes in the qualitative composition of phospholipid classes in blood plasma in patients treated with neurox. In patients treated with neipilept or with the combination of citicoline with 2-ethyl-6-methyl-3-hydroxypyridine succinate, plasma phosphatidylcholine was significantly increased. No significant changes in the content of phosphatidylinositol, phosphatidylserine and sphingomyelin were observed.

Erythrocytes as Potential Link between Diabetes and Alzheimer's Disease

Many studies support the existence of an association between type 2 diabetes (T2DM) and Alzheimer's disease (AD). In AD, in addition to brain, a number of peripheral tissues and cells are affected, including red blood cell (RBC) and because there are currently no reliable diagnostic biomarkers of AD in the blood, a gradually increasing attention has been given to the study of RBC's alterations. Recently it has been evidenced in diabetes, RBC alterations superimposable to the ones occurring in AD RBC. Furthermore, growing evidence suggests that oxidative stress plays a pivotal role in the development of RBC's alterations and vice versa. Once again this represents a further evidence of a shared pathway between AD and T2DM. The present review summarizes the two disorders, highlighting the role of RBC in the postulated common biochemical links, and suggests RBC as a possible target for clinical trials.

Differences of microparticle patterns between sickle cell anemia and hemoglobin SC patients

Sickle cell anemia (SCA) and hemoglobin SC (HbSC) disease are the two most common forms of sickle cell disease (SCD), a frequent hemoglobinopathy which exhibits a highly variable clinical course. Although high levels of microparticles (MPs) have been consistently reported in SCA and evidence of their harmful impact on the SCA complication occurrences have been provided, no data on MP pattern in HbSC patients has been reported so far. In this study, we determined and compared the MP patterns of 84 HbSC and 96 SCA children, all at steady-state, using flow cytometry. Most of circulating MPs were derived from platelets (PLTs) and red blood cells (RBCs) in the two SCD syndromes. Moreover, we showed that HbSC patients exhibited lower blood concentration of total MPs compared to SCA patients, resulting mainly from a decrease of MP levels originated from RBCs and to a lesser extent from PLTs. We did not detect any association between blood MP concentrations and the occurrence of painful vaso-occlusive crises, acute chest syndrome and pulmonary hypertension in both patient groups. We also demonstrated for the first time, that whatever the considered genotype, RBC-derived MPs exhibited higher externalized phosphatidylserine level and were larger than PLT-derived MPs.

Relationship between plasma glycation with membrane modification, oxidative stress and expression of glucose trasporter-1 in type 2 diabetes patients with vascular complications

BACKGROUND OF STUDY

Enhanced protein glycation in diabetes causes irreversible cellular damage through membrane modifications. Erythrocytes are persistently exposed to plasma glycated proteins; however, little are known about its consequences on membrane. Aim of this study was to examine the relationship between plasma protein glycation with erythrocyte membrane modifications in type 2 diabetes patients with and without vascular complications.

METHOD

We recruited 60 healthy controls, 85 type 2 diabetic mellitus (DM) and 75 type 2 diabetic patients with complications (DMC). Levels of plasma glycation adduct with antioxidants (fructosamine, protein carbonyl, β-amyloids, thiol groups, total antioxidant status), erythrocyte membrane modifications (protein carbonyls, β-amyloids, free amino groups, erythrocyte fragility), antioxidant profile (GSH, catalase, lipid peroxidation) and Glut-1 expression were quantified.

RESULT

Compared with controls, DM and DMC patients had significantly higher level of glycation adducts, erythrocyte fragility, lipid peroxidation and Glut-1 expression whereas declined levels of plasma and cellular antioxidants. Correlation studies revealed positive association of membrane modifications with erythrocyte sedimentation rate, fragility, peroxidation whereas negative association with free amino groups, glutathione and catalase.

CONCLUSION

Our data suggest that plasma glycation is associated with oxidative stress, Glut-1 expression and erythrocyte fragility in DM patients. This may further contribute to progression of vascular complications.

Diagnostic morphology: biophysical indicators for iron-driven inflammatory diseases

Most non-communicable diseases involve inflammatory changes in one or more vascular systems, and there is considerable evidence that unliganded iron plays major roles in this. Most studies concentrate on biochemical changes, but there are important biophysical correlates. Here we summarize recent microscopy-based observations to the effect that iron can have major effects on erythrocyte morphology, on erythrocyte deformability and on both fibrinogen polymerization and the consequent structure of the fibrin clots formed, each of which contributes significantly and negatively to such diseases. We highlight in particular type 2 diabetes mellitus, ischemic thrombotic stroke, systemic lupus erythematosus, hereditary hemochromatosis and Alzheimer's disease, while recognizing that many other diseases have co-morbidities (and similar causes). Inflammatory biomarkers such as ferritin and fibrinogen are themselves inflammatory, creating a positive feedback that exacerbates disease progression. The biophysical correlates we describe may provide novel, inexpensive and useful biomarkers of the therapeutic benefits of successful treatments.

Choline intake influences phosphatidylcholine DHA enrichment in nonpregnant women but not in pregnant women in the third trimester

BACKGROUND

Phosphatidylcholine (PC) produced via the S-adenosylmethionine-dependent phosphatidylethanolamine (PE) N-methyltransferase (PEMT) pathway is enriched with docosahexaenoic acid (DHA). DHA plays a critical role in fetal development and is linked to health endpoints in adulthood. It is unknown whether choline, which can serve as a source of S-adenosylmethionine methyl groups, influences PC-DHA or the PC:PE ratio in pregnant and nonpregnant women.

OBJECTIVE

This study tested whether choline intake affects indicators of choline-related lipid metabolism, including erythrocyte and plasma PC-DHA and PC:PE ratios, in pregnant women in the third trimester and nonpregnant women.

DESIGN

Pregnant (n = 26) and nonpregnant (n = 21) women consumed 480 or 930 mg choline/d and a daily DHA supplement for 12 wk. Blood was collected at baseline and at the midpoint and end of the study. PC-DHA was analyzed as the proportion of total PC fatty acids.

RESULTS

Pregnant women had greater (P = 0.002) PC-DHA concentrations than did nonpregnant women at baseline. The proportion of erythrocyte and plasma PC-DHA increased (P ≤ 0.002) in pregnant and nonpregnant women regardless of choline intake. However, in nonpregnant women, consumption of 930 mg choline/d led to greater (P < 0.001) erythrocyte PC-DHA and a more rapid increase (P < 0.001) in plasma PC-DHA. Lower (P = 0.001-0.024) erythrocyte and plasma PC:PE in pregnant women was not modified by choline intake.

CONCLUSIONS

A higher choline intake may increase PEMT activity, resulting in greater PC-DHA enrichment of the PC molecule in nonpregnant women. Increased production of PC-DHA during pregnancy indicates elevated PEMT activity and a higher demand for methyl donors. This trial was registered at clinicaltrials.gov as NCT01127022.

Changes in red blood cell membrane structure in type 2 diabetes: a scanning electron and atomic force microscopy study

Red blood cells (RBCs) are highly deformable and possess a robust membrane that can withstand shear force. Previous research showed that in diabetic patients, there is a changed RBC ultrastructure, where these cells are elongated and twist around spontaneously formed fibrin fibers. These changes may impact erythrocyte function. Ultrastructural analysis of RBCs in inflammatory and degenerative diseases can no longer be ignored and should form a fundamental research tool in clinical studies. Consequently, we investigated the membrane roughness and ultrastructural changes in type 2 diabetes. Atomic force microscopy (AFM) was used to study membrane roughness and we correlate this with scanning electron microscopy (SEM) to compare results of both the techniques with the RBCs of healthy individuals. We show that the combined AFM and SEM analyses of RBCs give valuable information about the disease status of patients with diabetes. Effectiveness of treatment regimes on the integrity, cell shape and roughness of RBCs may be tracked, as this cell’s health status is crucial to the overall wellness of the diabetic patient.

[Erythrocyte lipid composition at different stages of type 1 diabetes in children]

Complete profiles of phospholipid and ceramide molecular species from erythrocyte lipid extracts of children without carbohydrate metabolism disorders, and children with type 1 diabetes were compared by means of high performance liquid chromatography/mass spectrometry. For the first time a statistically significant increase (p<0.05) of lysophosphatidylcholine content in two groups of diabetic children with different duration of the disease (less than one year and more than one year) was found. Statistically significant changes in other lipid classes were not observed. The dependence of the content of phosphatidylcholine and phosphatidylethanolamine molecular species containing arachidonic acid residue (20:4) on the duration of the disease was found. The observed shift in lipid metabolism suggests of phospholipase A2 and chronic inflammatory process at different stages of diabetes mellitus, in cells (erythrocytes), which aer not involved in the immune response.

Analysis of the membrane fluidity of erythrocyte ghosts in diabetic, spontaneously hypertensive rats

Diabetes and hypertension are closely related diseases associated with changes in membrane fluidity. Here, we measured the membrane fluidity of erythrocyte ghosts from spontaneously hypertensive rats (SHR), with or without streptozotocin (STZ)-induced diabetes, at the ages of 1, 3 and 6 months, by introducing the use of the intramolecular excimer forming dipyrenylpropane (DPyP) in this model. Type 2 diabetes mellitus (T2DM) was induced in 48-h-old, newborn male SHR by intraperitoneal injection of STZ. We found lower excimer to monomer (I (e)/I (m)) DPyP ratios in diabetic SHR than in control SHR at 3 and 6 months old, indicating a decrease in membrane fluidity. Simultaneously, the composition of fatty acids was determined and it was found that the unsaturated to saturated fatty acids ratio (U/S) was compatible with changes in membrane fluidity. These results suggest that the change in fatty acid composition of erythrocyte ghosts contributes significantly to the decreased membrane fluidity detected with DPyP in diabetic SHR.

The Alterations of Erythrocyte Phospholipids in Type 2 Diabetes Observed after Oral High-Fat Meal Loading: The FTIR Spectroscopic and Mass Spectrometric Studies

Little is known about the postprandial remodelling of erythrocytes phospholipids (PLs) in type 2 diabetics (T2DM). Therefore, this study aims to compare the alterations of erythrocyte PLs in T2DM to those of healthy subjects after ingestion of a high-fat meal. Eleven T2DM and ten healthy subjects underwent a high-fat meal loading. Erythrocytes were isolated from blood obtained after fasting and 4 h after the meal. Fourier Transform Infrared (FTIR) spectroscopy was initially used to screen erythrocyte PLs by monitoring C-H stretching vibrations. Phosphatidylcholine (PC) molecular species were further investigated by Liquid Chromatography-Electrospray Ionisation-Mass Spectrometry (LC-ESI-MS). For the control group, FTIR revealed postprandial changes in C-H stretching vibrations, particularly of the olefinic band. These findings were supported by LC-ESI-MS data, showing marked changes in PC molecular species, especially of the PC34:1 (where 34 and 1 mean the summed number of carbons and double bonds, respectively). However, similar changes of those were not apparent in the T2DM group. Our results reveal marked postprandial alterations of erythrocyte PC species in healthy subjects whereas only mild alterations are observed in T2DM. The discrepant effects of high-fat meal loading suggest abnormal PC remodelling in the diabetic erythrocyte that may affect its membrane fluidity and integrity.

Increased cation conductance in human erythrocytes artificially aged by glycation

Excessive glucose concentrations foster glycation and thus premature aging of erythrocytes. The present study explored whether glycation-induced erythrocyte aging is paralleled by features of suicidal erythrocyte death or eryptosis, which is characterized by cell membrane scrambling with subsequent phosphatidylserine exposure at the cell surface and cell shrinkage. Both are triggered by increases of cytosolic Ca(2+) concentration ([Ca(2+)](i)), which may result from activation of Ca(2+) permeable cation channels. Glycation was accomplished by exposure to high glucose concentrations (40 and 100 mM), phosphatidylserine exposure estimated from annexin binding, cell shrinkage from decrease of forward scatter, and [Ca(2+)](i) from Fluo3-fluorescence in analysis via fluorescence-activated cell sorter. Cation channel activity was determined by means of whole-cell patch clamp. Glycation of total membrane proteins, immunoprecipitated TRPC3/6/7, and immunoprecipitated L-type Ca(2+) channel proteins was estimated by Western blot testing with polyclonal antibodies used against advanced glycation end products. A 30-48-h exposure of the cells to 40 or 100 mM glucose in Ringer solution (at 37 degrees C) significantly increased glycation of membrane proteins, hemoglobin (HbA(1c)), TRPC3/6/7, and L-type Ca(2+) channel proteins, enhanced amiloride-sensitive, voltage-independent cation conductance, [Ca(2+)](i), and phosphatidylserine exposure, and led to significant cell shrinkage. Ca(2+) removal and addition of Ca(2+) chelator EGTA prevented the glycation-induced phosphatidylserine exposure and cell shrinkage after glycation. Glycation-induced erythrocyte aging leads to eryptosis, an effect requiring Ca(2+) entry from extracellular space.

An approach to the identification of the phospholipid molecular species in human erythrocytes using HPLC with mass-spectrometric detection

A modified RP-HPLC-MS approach has been proposed for a single run separation and identification of the molecular species of different phospholipid classes in a complex extract. This approach has been applied to the analysis of glycero- and sphingolipid composition of human erythrocytes and a number of ceramide fractions have been identified; these fractions was missed in previous studies employing similar methods. The fine experimental design leads to the decrease in the number of procedures needed for a complete phospholipid profiling of the sample.

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.

Determination of membrane lipid differences in insulin resistant diabetes mellitus type 2 in whites and blacks

OBJECTIVES

Insulin resistance in diabetes mellitus type 2 (DM2) can result from membrane lipid alterations. Blacks are at a higher risk of developing DM2; therefore, we investigated whether membrane lipid differences exist between blacks and whites and if differences contribute to impaired insulin binding in diabetes.

METHODS

Subjects were recruited from four groups: white control (n = 10), black control (n = 10), white diabetic (n = 5), and black diabetic (n = 10). Diabetic subjects who had DM2 with insulin resistance on insulin monotherapy were matched by age and sex. The following determinations were made: fasting serum glucose, fasting serum insulin, plasma lipid profile, red blood cell (RBC) membrane lipids and cholesterol, and RBC insulin binding.

RESULTS

The membrane lipid analysis showed racial differences in phosphatidyl ethanolamine (PE) and phosphatidyl choline (PC). The plasma membrane of whites showed higher PE and lower PC levels than that in blacks. The RBC rheologic (PE/phosphatidyl serine) properties (deformability) were lower in diabetics and black subjects. The saturated nature of RBC ([sphingomyelin + PC)/(PE + phosphatidyl serine]) was the lowest in white control subjects (P < 0.056).

CONCLUSION

The combination of increased saturated/polyunsaturated fatty acids, increased saturated nature, and increased cholesterol/phospholipid can contribute to decreased membrane fluidity, resulting in insulin resistance. Also, decreased RBC deformability can make oxygen delivery through the capillaries difficult, create tissue hypoxia, and contribute to some of the known complications of diabetes. Membrane lipid alteration may be one of the reasons for a higher incidence of diabetes among blacks.

Altered red cell turnover in diabetic mice

In diabetes, a subpopulation of red cells expose phosphatidylserine, and the size of this subpopulation of cells is related to blood glucose levels. Because phosphatidylserine exposure can lead to the recognition and removal of red cells we hypothesized that red cell survival would be altered. In this study, diabetic female mice (db/db) and heterozygous littermate controls were used to explore relationships between red cell characteristics, phosphatidylserine exposure, and red cell survival. Red cell turnover was assessed using random red cell labeling with biotin. To determine if phosphatidylserine exposure was related to age, red cells were double-labeled and analyzed by flow cytometry. Cellular characteristics were measured by flow cytometry and ektacytometry. While red cell removal was linear for the control mice, for the diabetic mice an exponential survival curve was noted with an extended survival of a subpopulation of cells. The subpopulation of red cells exposing phosphatidylserine was significantly increased in the diabetic mice relative to the control mice (0.9% +/- 0.07%, n = 12, and 0.6% +/- 0.05 %, n = 22, respectively; P =.007). This subpopulation increased during the life of the red cell, with a higher rate of increase in the diabetic mice. Red cell hemoglobin content and cell volume were abnormal, but no obvious signs of anemia were found in the diabetic animals. A normal hematocrit, low reticulocyte count, and a much reduced spleen in these animals were consistent with a low red cell turnover. The presence of a population of older phosphatidylserine exposing cells indicates altered red cell removal and suggests a role for older red cells in vascular damage.

Effect of mulberry (Morus indica L.) therapy on plasma and erythrocyte membrane lipids in patients with type 2 diabetes

BACKGROUND

Mulberry (Morus indica L.) is non-toxic natural therapeutic agent shown to possess hypoglycemic, hypotensive, and diuretic properties.

METHODS

The hypoglycemic effect of the mulberry leaves was evaluated by comparing the anti-diabetic activity of the standard drug, glibenclamide. A total of 24 type 2 diabetic patents were divided randomly into two treatment groups: the mulberry agent and glibenclamide, for 30 days. Serum and erythrocyte membrane lipid profiles of the patients were analyzed before and after the treatments.

RESULTS

Patients with mulberry therapy significantly improved their glycemic control vs. glibenclamide treatment. The results from pre- and post-treatment analysis of blood plasma and urine samples showed that the mulberry therapy significantly decreased the concentration of serum total cholesterol (12%, p<0.01), triglycerides (16%, p<0.01), plasma free fatty acids (12%, p<0.01), LDL-cholesterol (23%, p<0.01), VLDL-cholesterol (17%, p<0.01), plasma peroxides (25%, p<0.01), urinary peroxides (55%, p<0.01), while increasing HDL-cholesterol (18%, p<0.01). Although the patients with glibenclamide treatment showed marginal improvement in glycemic control, the changes in the lipid profile were not statistically significant except for triglycerides (10%, p<0.05), plasma peroxides (15%, p<0.05), and urinary peroxides (19%, p<0.05). Both treatments displayed no apparent effect on the concentrations of the glycosylated hemoglobin (Hb A(1)c) in diabetic patients. However, the fasting blood glucose concentrations of diabetic patients were significantly reduced by the mulberry therapy.

CONCLUSIONS

Mulberry therapy exhibits potential hypoglycemic and hypolipidemic effects in diabetic patients.

Oxidative response and membrane modification of diabetic platelets challenged with PAF

Alterations in the functional activities of platelets (PLT) in type I diabetes have been widely observed. These changes play a key role in the development of cardiovascular complications in diabetes. Various functional activities of PLT are the result of the interaction of numerous stimuli with PLT plasma membrane. This study was designed to evaluate the oxidative response and membrane modifications of diabetic PLT stimulated by platelet activating factor (PAF). The oxidative response was assessed by employing luminol- and lucigenin-amplified chemiluminescence. Luminol-amplified chemiluminescence is sensitive to the release of hydrogen peroxide whereas lucigenin-amplified chemiluminescence is sensitive to the production of superoxide anion. Membrane fluidity and polarity were studied using fluorescence spectroscopy. Membrane fluidity was investigated by measuring steady-state fluorescence anisotropy of 1-[4-trimethylammonium-phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH) and membrane polarity was studied by measuring the steady-state fluorescence emission and excitation spectra of 2-dimethylamino[6-lauroyl]-naphthalene (Laurdan). The diabetic group consisted of 20 type I diabetic children with good metabolic control. Our results show a significant decrease in the luminol- and lucigenin-amplified chemiluminescence of PAF stimulated PLT in the diabetic group with respect to controls. These data indicate a decrement in the release of reactive oxygen species by diabetic PLT. We observed a significant increase in steady-state fluorescence anisotropy of diabetic PLT membrane that reflects a decrease in membrane fluidity. Laurdan showed a blue shift of the fluorescence emission and excitation spectra in diabetic PLT with respect to the control group, indicating a decrease in membrane polarity. The addition of PAF to PLT induced a red shift of Laurdan spectra in both groups, indicating an increase in membrane polarity. Our study [table: see text] demonstrates an altered oxidative response to PAF stimulation of diabetic PLT, probably due to altered generation or handling of reactive oxygen species, and alterations in the physico-chemical properties of the plasma membrane which could influence various functional activities of PLT.

Plasma membrane fluidity and polarity of polymorphonuclear leukocytes from children with type I diabetes mellitus

Polymorphonuclear leukocytes (PMN) from diabetic subjects have been found to be abnormal in various functional activities. These activities are mediated by the plasma membrane. This study was designed to evaluate plasma membrane fluidity and polarity in children with type I diabetes mellitus using fluorescence spectroscopy. PMN membrane fluidity and polarity were assessed in a group of 32 diabetic children. Membrane fluidity was investigated by measuring steady-state fluorescence anisotropy and fluorescence decay of 1-[4-trimethylammonium-phenyl]-6-phenyl- 1,3,5-hexatriene (TMA-DPH), whereas membrane polarity was studied by measuring the steady-state fluorescence emission and excitation spectra of 2-dimethylamino[6-lauroyl]-naphthalene (Laurdan). TMA-DPH and Laurdan are known to be incorporated at the hydrophobic-hydrophilic interface of the bilayer. Our data show a significant increase in steady-state fluorescence anisotropy in diabetic PMN that reflects a decrease in membrane fluidity, and a decrease in TMA-DPH lifetime distribution indicating a decrease in membrane heterogeneity. Laurdan shows a blue shift of the fluorescence emission and a red shift of the excitation spectra in diabetic PMN with respect to the control group, indicating a decrease in membrane polarity. The results demonstrate a decrease in the phospholipid order at the membrane surface and a decrease in membrane polarity in diabetic PMN. These alterations in the physico-chemical properties of the plasma membrane could be the basis of the modifications in functional activities of PMN. The changes in the plasma membrane of PMN could be the result of metabolic and chemical modification associated with type I diabetes.

Fatty acid composition of phospholipids and neutral lipids from human diabetic small arteries and veins by a new TLC method

It has been suggested that lipid peroxidation of polyunsaturated fatty acids (PUFA) may play a role in the pathogenesis of diabetic complications. To test this hypothesis, we aimed to compare PUFA composition of small arteries and veins (< 500 microm diameter) obtained from diabetic or non-diabetic Guadeloupean patients undergoing arterio-venous shunt surgery before renal dialysis. Small forearm subcutaneous vessels were analysed by a new TLC method which involved inclusion of vascular biopies directly in alveoles made in the TLC gel and lyophilization onto the plate. The TLC plate was then chromatographed and lipids were both extracted and eluted during this step. Fatty acid composition of phospholipid and neutral lipid fractions were determined. Similar fatty acid composition was obtained for arteries and veins from diabetic or non-diabetic subjects. In phospholipids from diabetic vessels, major changes consisted of a 20% decrease of arachidonic acid (20:4 n-6), a 40% decrease of its elongation product 22:4 n-6 and 30% increase of 18:2 n-6. In neutral lipids, 20:4 n-6 was also diminished by 60% whereas oleic acid increased by 15%. This loss of arachidonic acid in small diabetic vessels suggests impaired delta6-desaturase forming 20:4 n-6 or alternatively increased peroxide formation, in the vascular wall of small vessels in diabetic patients.

Microangiopathic hemolytic anemia as a complication of diabetes mellitus

A mature-onset diabetic patient who developed microangiopathic hemolytic anemia (MHA) is presented. Although numerous causes of hemolysis are reported in the literature, MHA is a rare complication of diabetes. The proposed mechanism of hemolytic anemia is thought to be related to the abnormal formation of cell membranes in the diabetic environment. The ratio of cholesterol to phospholipid in the core of the membrane is altered in diabetics; as a result, the red blood cell wall becomes rigid and nondeformable. The abnormal cells becomes disrupted as they circulate through the microangiopathic blood vessels. The mechanism of action of the antiplatelet agents is to enhance cell membrane compliance. With improved cell-wall compliance, one can expect a reduction in hemolysis, as occurred in our patient. The literature on diabetes mellitus-related microangiopathic hemolytic anemia is reviewed.