An evaluation of the rheological properties and the effects of
Diabetes mellitus is a metabolic disease characterized by elevated blood glucose levels. It results from the absence of, or inadequate levels of, pancreatic insulin secretion, with or without concurrent impairment of insulin action [
Diabetic patients have endothelial dysfunction and damage caused to the vessel wall [
The pathophysiology of vascular disease in diabetes involves abnormalities in endothelial, vascular smooth muscle cell and platelet function. The metabolic abnormalities that characterize diabetes, such as hyperglycemia, increased free fatty acids, and insulin resistance, can provoke molecular mechanisms that contribute to vascular dysfunction [
Reports in the literature suggest that increased serum osmolarity of the blood occurs in diabetic patients due to high sugar concentrations [
Red blood cell rheology is altered in different diseases, including diabetes [
Rheological alterations can be verified by the deformation or aggregation of erythrocytes, blood flow [
Because of the changes in blood viscosity in the pathogenesis of diabetes, rheology can be an important tool in monitoring patients with diabetes mellitus [
Various experimental studies have shown that plants have the ability to reduce glucose levels [
On the other hand, polyethylene glycol (PEG) microspheres are polymeric particles that absorb organic compounds and are used experimentally as a carrier molecule. They can be modified to improve their biological function and are useful for the delivery of a variety of substances or therapeutic plants [
Despite the importance and high incidence of this disorder [
Samples of 15 mL of blood were collected from 56 volunteers normoglycemic and 26 volunteers with type II diabetes mellitus, noninsulin dependent without micro- or macroangiopathy. Blood samples were stored in heparinized (25 U mL−1) tubes. The volunteers signed an informed consent form that was approved by the Local Ethics Committee before entering the study.
The controlled variables were smoking status (yes/no), arterial hypertension (yes/no), and glycemic index (GI) based on mean plasma glucose level. The GI was classified as normoglycemic (GI < 120 mg dL−1) or hyperglycemic (GI ≥ 120 mg dL−1).
Glucose levels were determined by an enzymatic system. Samples of 10
To calculate BMI (mass/stature²) values
The plants were collected and deposited in the herbarium at the Institute of Biological and Health Science-Federal University of Mato Grosso, Pontal do Araguaia, MT, Brazil, located at Lat. 15°55′08′′S and Long. 52°16′44′′W at an altitude of 365 m. Preparation of the plants involved a mixing process followed by maceration according to the Brazilian pharmaceutical code [
The microspheres were obtained from Poly(ethylene glycol) (PEG) 6000 (Sigma, ST Louis, USA) using a modification protocol [
To assess the effects of
To investigate the effects on rheological parameters of PEG microspheres adsorbed with
The rheological parameters were measured using the Modular Compact Rheometer—MCR 102 (Anton Paar GmbH, Ostfildern, Germany). In all experiments, 600
For the viscosity curve under temperature scan, established parameters were based on fixed control shear stress (
The statistically significant difference was evaluated using the analysis of variance (ANOVA) and the statistical significance was considered for a
Age, stature, abdominal circumference, body mass, and body mass index were similar between the two groups. The erythrocyte and leukocyte concentrations were similar between normoglycemic and diabetic groups. The glucose concentration was higher in the diabetic group than in the normoglycemic group (Table
General and hematological characteristics of the experimental groups.
Parameters | Normoglycemic | Hyperglycemic | Statistics |
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Age (year) |
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Stature (m) |
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Body mass (kg) |
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Abdominal circumference (cm) |
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Body mass index (BMI) |
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Erythrocytes (106 |
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Leukocytes (106 cells mL−1) |
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Glycemia (mg dL−1) |
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Data are represented by mean ± standard deviation (SD). *Statistical differences (
The rheological profiles of the blood of normo- and hyperglycemic individuals are shown in Figure
Flow curve of normoglycemic and hyperglycemic whole blood. *No statistical difference
In Figures
Viscosity curve of normoglycemic and hyperglycemic whole blood under a temperature scan (25 at 45°C). *Statistical difference
Viscosity curve of normoglycemic and hyperglycemic whole blood. *Amplification of the region with a statistical difference
When blood from both groups was treated with
Viscosity curves of normoglycemic and hyperglycemic whole blood after treatment. (a) Treatment with
The effects of PEG microspheres on blood viscosity in the experimental groups are described in Figure
The viscosity profile of whole blood from hyperglycemic and normoglycemic patients treated with nanoparticles of
The mean viscosities of whole blood and the respective treatment groups are summarized in Table
Viscosity of whole blood in the different groups.
Experimental |
Viscosity (Pa·s × 10−3) | Statistics | |
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Normoglycemic | Hyperglycemic | ||
Whole blood |
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WB |
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WB PEG |
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WB PEG |
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Data are represented by mean ± standard deviation (SD). *Differences (
This study showed that the blood from hyperglycemic patients exhibits changes in the viscosity and that nanoparticles of an extract of
The evidence underestimates the overall difference in rheological properties between diabetic and control lymphocytes [
In this study, the rheological profile of the blood flow, independent of glycemic levels, does not show the characteristic behavior of ideal liquids. Instead of a straight line, there is a flow curve starting from the origin of the flow. The ascendant and nonlinear behavior starting at the origin characterizes the fluids, nonNewtonian and pseudoplastic, for these shear conditions [
The lack of superimposition of the ascending and descending curves with an area of hysteresis was observed in this study, demonstrating that thixotropic properties are present in the blood flow. In the literature, study demonstrates that thixotropic behavior in diabetes blood is substantially increased. The diabetic pattern appears produced by a combination of reduced erythrocyte deformability and increased erythrocyte aggregation due to plasma protein changes [
The integrity of this property is important, because it shows that the blood has the potential for reversible deformation in the various conditions of shear that blood flow undergoes [
This work evaluates the influence of temperature on the dynamic variation of the viscosity of blood tissue; it was observed that the blood of hyperglycemic patients has a greater viscosity over a wide temperature range and at physiological temperatures, which can trigger adaptation and deformation difficulties.
Previous studies concluded that untreated children with diabetes show more pronounced alterations of erythrocyte and PMN deformability than insulin-treated diabetic children. High counts of rigid active PMN, impaired deformability of resting PMN, and decreased flexibility of erythrocytes at low flow may all contribute to the high risk that children with diabetes have for acute vascular complications [
In the literature, studies of healthy subjects revealed that the rate of elongation (representing the deformability) decreased significantly with temperature reductions of 37°C to 5°C [
According to the results of recent clinical trials, therapeutic aphaeresis reducing the concentration of
On the other hand, several studies have shown that ethnopharmacological medicinal plants exhibit beneficial effects on various diseases and could be alternative treatments principally in chronic degenerative diseases, such as diabetes [
The reduction in the viscosity of hyperglycemic blood by
The therapeutic properties of compounds isolated from plants and their incorporation into controlled release systems offer an important strategy for developing drugs with intelligent properties. In the literature, the immunomodulatory effects of PEG microspheres adsorbed with
The development of plant-based drugs in nanoscale doses presents a number of advantages, including enhancements of solubility and bioavailability, protection from toxicity, enhancement of pharmacological activity, enhancement of stability, improving tissue macrophage distribution, sustained delivery, and protection from physical and chemical degradation [
The clinical potential for the use of PEG microsphere adsorbed with
The literature also reports that, in addition to diabetes, rheological parameters are used in cardiovascular research, with value for the detection of patients who are prone to cardiovascular disease, monitoring women at risk of pre-eclampsia, assessing hydration status in patients prior to undergoing surgery or catheterization, and monitoring blood viscosity at low temperatures such as in bypass surgery. In addition, its use will facilitate the development of new drugs able to specifically reduce whole blood viscosity by influencing factors such as red blood cell deformability [
These data suggest that the effects of diabetes on the viscosity of the blood should be considered. The use of nanofraction extracts of
The authors declare no conflict of interests and nonfinancial competing interests.
This research received Grants from Fundação de Amparo à Pesquisa de Mato Grosso (FAPEMAT no. 299032/2010), Conselho Nacional de Pesquisa (CNPq), and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, CAPES, Brazil.