Influence of Glucose Concentration on the Membrane Stability of Human Erythrocytes

A Multi-Level Approach as a Powerful Tool to Identify and Characterize Some Italian Autochthonous Common Bean (Phaseolus vulgaris L.) Landraces under a Changing Environment

A prime role in matters of agrobiodiversity is held by landraces, which serve as a repository gene pool able to meet sustainable development goals and to face the ongoing challenges of climate change. However, many landraces are currently endangered due to environmental and socio-economic changes. Thus, effective characterization activities and conservation strategies should be undertaken to prevent their genetic and cultural erosion. In the current study, the morphological, genetic, and biochemical analyses were integrated with stress response-related studies to characterize the diversity of seven Italian autochthonous common bean landraces. The results showed that the morphological descriptors and the neutral molecular markers represent powerful tools to identify and distinguish diversity among landrace populations, but they cannot correlate with the stress tolerance pattern of genetically similar populations. The study also supported the use of proline as a biochemical marker to screen the most salt-sensitive bean landraces. Thus, to fully elucidate the future dynamics of agrobiodiversity and to establish the basis for safeguarding them while promoting their utilization, a multi-level approach should always be included in any local and national program for the characterization/conservation/use of genetic resources. This study should represent the basis for further joint research that effectively contributes to set/achieve Italian priorities towards sustainability in the framework of emerging environmental, societal, and economic challenges.

Methods: A new protocol for in vitro red blood cell glycation

During diabetes, the characteristic hyperglycemia can induce red blood cell glycation. Several researchers have proposed different protocols to perform an in vitro model to study this phenomenon. In this article, some of the most important in vitro glycation protocols available in the bibliography were compared to each other. The incubation parameters as the suspension medium, glucose concentration, red blood cell concentration, time, and temperature were analyzed. Also, several assays were carried out in our laboratory, and glycated hemoglobin, erythrocyte aggregation and viscoelasticity were determined for the protocol validation. Based on the bibliographic analysis and our experimental results, an optimal protocol for in vitro glycation of red blood cells is presented.

Applications of artificial membrane feeding for ixodid ticks

Ticks are obligatory hematophagous ectoparasites that feed on a large variety of vertebrates. In the laboratory, animals (mainly mice and rabbits) are used to maintain tick colonies. However, the use of animals to rear ticks can be expensive and requires dedicated animal facilities. In addition, research institutions are committed to the principle of 3Rs (Replacement, Reduction and Refinement), which encourages the use of alternatives to animals when possible. The development of artificial membrane systems has provided an alternative to animals, at least for some tick species. Over the years, different modifications in artificial feeding systems have led to new applications, including acaricide testing, tick-pathogen interaction, and novel approaches to study tick physiology. Although artificial membrane feeding still has some limitations, the method can provide numerous advantages, including the standardization of acaricide treatments under controlled conditions, an alternative to animals for tick rearing, and reduction of cost associated with animals and animal housing facilities. In this review, we summarized the evolution of tick feeding membranes and their applications over time, explaining the modifications incorporated to study tick physiology, tick-pathogen interactions, and acaricide testing.

Products of Lipid Peroxidation as a Factor in the Toxic Effect of Silver Nanoparticles

In our previous study we have shown that nanoparticles have different effects depending on the energy metabolism of the cell, which is an important factor in the context of oncology and diabetes. Here we assess the influence of AgNPs on cellular lipid components in varying glucose concentrations. To assess the effect of silver nanoparticles on cell lipids, we measured cell viability, the fluidity of the cell membranes, the content of amino groups in proteins, the level of lipid peroxidation products, the concentration of 4-hydroxynonenal (4-HNE), and the concentration of lipid peroxides. The obtained results show differences in the formation of lipid peroxidation products in cells exposed to oxidative stress induced by nanoparticles. In addition, we have shown that the metabolic state of the cell is a factor significantly affecting this process.

Correlations of the glycemic variability with oxidative stress and erythrocytes membrane stability in patients with type 1 diabetes under intensive treatment

OBJECTIVES

This study aimed to evaluate the correlations of glycemic variability with erythrocyte membrane stability parameters and oxidative stress markers in patients with type 1 diabetes mellitus (T1DM) under intensive treatment.

MATERIAL AND METHODS

90 patients with T1DM and under intensive treatment of the disease were evaluated in relation to anthropometric indices, records of glycemic averages and parameters of glycemic variability, biochemical dosages (glucose, uric acid, lipidogram, glycated hemoglobin, microalbuminuria, creatinine and iron) reticulocyte count, erythrocyte membrane stability parameters and oxidative stress markers (thiobarbituric acid reactive substances, TBARS, and glutathione reductase, GR).

RESULTS

Indicators of glycemic variability in the short and long term showed correlations with parameters of membrane stability and markers of oxidative stress (GR). In addition, the comparison of these same parameters between the subgroups consisting of quartiles of GV or glycemic control also showed significant differences.

CONCLUSION

In the T1DM patients studied here, glycemic variability showed correlations with oxidative stress and erythrocyte membrane stability variables. This corroborates the hypothesis that glycemic fluctuations interfere with lipid peroxidation and cell membrane behavior, emphasizing its participation in mechanisms related to the development of chronic complications of diabetes.

Are There Differences in the Anthropometric, Hemodynamic, Hematologic, and Biochemical Profiles between Late- and Early-Onset Preeclampsia?

Preeclampsia (PE) is classified as early-onset PE (EOPE) and late-onset PE (LOPE) when present before or after 34 weeks of gestation, respectively. This transversal study aimed to investigate the differences and possible associations existing in the anthropometric, hemodynamic, hematologic, and biochemical profiles of late- and early-onset preeclampsia. The study included 65 volunteers admitted to a tertiary hospital in Brazil: 29 normotensive and 36 with preeclampsia (13 with EOPE and 23 with LOPE). Pregnant women with LOPE presented greater weight gain and borderline increase in body mass index at the end of gestation in relation to the other groups, which is compatible with the metabolic origin, associated with obesity, attributed to this form of the disease. Pregnant women with EOPE presented a borderline reduction in the number of erythrocytes and a significant decrease in the number of platelets, in addition to a significant increase in reticulocytes, serum iron, and ferritin when compared to normotensive pregnant women and pregnant women with LOPE. A significant increase in osmotic stability of erythrocytes was observed in the EOPE group in relation to other groups. Hemodynamic analysis by Doppler ultrasonography of the ophthalmic artery showed that both groups of pregnant women with PE presented alterations compatible with the occurrence of hyperflow in the orbital territory. These hemodynamic changes were associated with changes in hematimetric indices.

Effects of acute and chronic exercise on the osmotic stability of erythrocyte membrane of competitive swimmers

This study aimed to evaluate the influence of acute and chronic exercise on erythrocyte membrane stability and various blood indices in a population consisting of five national-level male swimmers, over 18 weeks of training. The evaluations were made at the beginning and end of the 1st, 7th, 13th and 18th weeks, when volume and training intensity have changed. The effects manifested at the beginning of those weeks were considered due to chronic adaptations, while the effects observed at the end of the weeks were considered due to acute manifestations of the exercise load of that week. Acute changes resulting from the exercise comprised increases in creatine kinase activity (CK) and leukocyte count (Leu), and decrease in hematocrit (Ht) and mean corpuscular volume (MCV), at the end of the first week; increase in the activities of CK and lactate dehydrogenase (LDH), in the uric acid (UA) concentration and Leu count, at the end of the seventh week; increases in CK and LDH activities and in the mean corpuscular hemoglobin concentration (MCHC), at the end of the 13th week; and decrease in the value of the osmotic stability index 1/H₅₀ and increases in the CK activity and platelets (Plt) count, at the end of the 18th week. Chronic changes due to training comprised increase in the values of 1/H₅₀, CK, LDH, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), serum iron (Fe), MCV and Plt. Although acute training has resulted in decrease in the osmotic stability of erythrocytes, possibly associated with exacerbation of the oxidative processes during intense exercise, chronic training over 18 weeks resulted in increased osmotic stability of erythrocytes, possibly by modulation in the membrane cholesterol content by low and high density lipoproteins.

Optimization of an artificial tick feeding assay for Dermacentor reticulatus

BACKGROUND

The development of standardized in vitro feeding methods for ixodid ticks has been hampered by their complex feeding behaviour and the long duration of their blood meal. In this study, we aimed to optimize several parameters for the in vitro feeding of adult Dermacentor reticulatus.

METHODS

Ticks were fed on heparinized bovine blood collected at a slaughterhouse, using a modified silicone membrane feeding assay. Effects on tick feeding and fecundity of different blood meal treatments (freezing, irradiation, addition of antibiotics), ambient conditions (increased CO₂ concentration) and phagostimulant use (addition of 2 g/l and 4 g/l glucose to the blood meal) were systematically evaluated.

RESULTS

Although fungal growth occurred more frequent in feeding units of ticks fed on defrosted blood, the attachment rate, engorgement mass and fecundity of females fed on defrosted blood did not significantly differ from that of ticks fed on fresh blood. A reduction in the fecundity of female D. reticulatus ticks was observed when ticks were fed with gamma-irradiated blood or untreated blood compared to blood treated with gentamycin. Both the engorgement mass and fecundity increased when ticks were fed at a 5% CO₂ level. A non-significant increase in the engorgement mass and engorgement rate of D. reticulatus was observed when blood was supplemented with 4 g glucose per litre compared to 2 g/l.

CONCLUSION

An artificial feeding method was adapted for the feeding of adult D. reticulatus ticks. Of all parameters tested, only the artificial feeding at 5% CO₂ levels resulted in a significant increase (P < 0.05) in the engorgement mass and fecundity of female D. reticulatus ticks. The supplementation of blood with antibiotics resulted in a significantly higher tick fecundity in comparison to ticks fed with untreated or irradiated blood.

The effect of incubation conditions on the hemolytic properties of unmodified graphene oxide with various concentrations

The hemolytic properties of graphene oxide (GO) were evaluated from the novel view of the incubation conditions.

Phenotypic variations in osmotic lysis of Sahel goat erythrocytes in non-ionic glucose media

BACKGROUND

Erythrocyte osmotic lysis in deionised glucose media is regulated by glucose influx, cation efflux, and changes in cell volume after water diffusion. Transmembrane fluxes may be affected by varied expression of glucose transporter protein and susceptibility of membrane proteins to glucose-induced glycosylation and oxidation in various physiologic states.

METHODS

Variations in haemolysis of Sahel goat erythrocytes after incubation in hyposmotic non-ionic glucose media, associated with sex, age, late pregnancy, and lactation, were investigated.

RESULTS

The osmotic fragility curve in glucose media was sigmoidal with erythrocytes from goats in late pregnancy (PRE) or lactation (LAC) or from kid (KGT) or middle-aged (MGT) goats. Non-sigmoidal phenotype occurred in yearlings (YGT) and old (OGT) goats. The composite fragility phenotype for males and non-pregnant dry (NPD) females was non-sigmoidal. Erythrocytes with non-sigmoidal curves were more stable than those with sigmoidal curves because of inflectional shift of the curve to the left. Erythrocytes tended to be more fragile with male than female sex, KGT and MGT than YGT and OGT, and LAC and PRE than NPD. Thus, sex, age, pregnancy, and lactation affected the haemolytic pattern of goat erythrocytes in glucose media.

CONCLUSIONS

The physiologic state of the goat affected the in vitro interaction of glucose with erythrocytes, causing variations in osmotic stability with variants of fragility phenotype. Variations in the effect of high extracellular glucose concentrations on the functions of membrane-associated glucose transporter, aquaporins, and the cation cotransporter were presumed to be relevant in regulating the physical properties of goat erythrocytes under osmotic stress.

Influence of extracellular media's ionic strength on the osmotic stability of Sahel goat erythrocytes

BACKGROUND

Heparinised blood was exposed to osmotic lysis in hypotonic buffered saline to evaluate erythrocyte membrane stability. When K3 EDTA blood was used, it added more to the ionic content of blood than heparin. The influence of suspending media's ionic strength on the osmotic stability of Sahel goat erythrocytes was investigated by replacing the ionic saline with non-ionic saccharide (sucrose or glucose) and assessing the effect of using EDTA blood instead of heparinised blood.

RESULTS

The erythrocyte osmotic fragility curve in saline was hyperbolic even when the ionic concentration was reduced by 50% with saccharides. Haemolysis was higher with EDTA than heparinised blood at saline concentrations of 90 and 150-180 mosmol/L. The fragility curve was sigmoidal and shifted to the left when saline was completely substituted with a saccharide. The non-ionic saccharides increased erythrocyte osmotic resistance linearly (r=0.88; p<0.02) from median to minimal hyposmolarities (150-300 mosmol/L) and reduced the osmolyte concentration at median fragility by 36%. No effect occurred at <30-120 mosmol/L and >90% fragility; and saccharide concentrations were almost non-lytic at comparable saline concentrations evoking <10% haemolysis. Fragilities were neither affected by period (30-60 min) of incubation nor the type of saccharide used.

CONCLUSIONS

In this study, the variation in osmotic stability of caprine erythrocytes was linked to ionic strength of the suspending extracellular media which seemed to exert an influence through transmembrane ion fluxes and regulatory volume changes in erythrocytes.

Relationship between serum cholesterol and indices of erythrocytes and platelets in the US population

Whereas dyslipidemia has been associated with leukocytosis, the relationship between serum cholesterol and other hematopoietic lineages is poorly defined. Erythrocytes and platelets, anucleate cells relegated to nonspecific diffusional exchange of cholesterol with serum, have been proposed to have a distinct relationship to cholesterol from leukocytes. We examined the relationship between serum cholesterol and circulating erythrocyte/platelet indices in 4,469 adult participants of the National Health and Nutrition Examination Survey (NHANES) 2005-2006. In linear regression analyses, serum non-high density lipoprotein-cholesterol (non-HDL-C) was positively associated with mean erythrocyte number, hematocrit, hemoglobin concentration, platelet count, and platelet crit independently of age, gender, race/ethnicity, smoking, body mass index, serum folate, and C-reactive protein. The magnitude of the relationship was most marked for platelets, with lowest versus highest non-HDL-C quartile subjects having geometric mean platelet counts of 258,000/μl versus 281,000/μl, respectively (adjusted model, P < 0.001 for trend). These associations persisted in a sensitivity analysis excluding several conditions that affect erythrocyte/platelet and/or serum cholesterol levels, and were also noted in an independent analysis of 5,318 participants from NHANES 2007-2008. As non-HDL-C, erythrocytes, and platelets all impact cardiovascular disease risk, there is a need for advancing understanding of the underlying interactions that govern levels of these three blood components.

Bivariate and multivariate analyses of the influence of blood variables of patients submitted to Roux-en-Y gastric bypass on the stability of erythrocyte membrane against the chaotropic action of ethanol

The stability of the erythrocyte membrane, which is essential for the maintenance of cell functions, occurs in a critical region of fluidity, which depends largely on its composition and the composition and characteristics of the medium. As the composition of the erythrocyte membrane is influenced by several blood variables, the stability of the erythrocyte membrane must have relations with them. The present study aimed to evaluate, by bivariate and multivariate statistical analyses, the correlations and causal relationships between hematologic and biochemical variables and the stability of the erythrocyte membrane against the chaotropic action of ethanol. The validity of this type of analysis depends on the homogeneity of the population and on the variability of the studied parameters, conditions that can be filled by patients who undergo bariatric surgery by the technique of Roux-en-Y gastric bypass since they will suffer feeding restrictions that have great impact on their blood composition. Pathway analysis revealed that an increase in hemoglobin leads to decreased stability of the cell, probably through a process mediated by an increase in mean corpuscular volume. Furthermore, an increase in the mean corpuscular hemoglobin (MCH) leads to an increase in erythrocyte membrane stability, probably because higher values of MCH are associated with smaller quantities of red blood cells and a larger contact area between the cell membrane and ethanol present in the medium.