Exogenous normal lymph alleviates microcirculation disturbances and abnormal hemorheological properties in rats with disseminated intravascular coagulation

Disturbances of the microcirculation and abnormal hemorheological properties are important factors that play an important role in disseminated intravascular coagulation (DIC) and result in organ dysfunction or failure. In the present study, we established an animal model of DIC using intravenous Dextran 500 in rats, and used exogenous normal lymph corresponding to 1/15 of whole blood volume for injection through the left jugular vein. We found that normal lymph could improve the blood pressure and survival time of rats with DIC. The results regarding the mesenteric microcirculation showed that the abnormality of the diameter of mesenteric microvessels and micro-blood flow speed in the DIC+lymph group was significantly less than in the DIC+saline group. Whole blood viscosity, relative viscosity, plasma viscosity, hematocrit (Hct), erythrocyte sedimentation rate (ESR), and electrophoresis time of erythrocytes were significantly increased in the DIC+saline group compared to the control group. The electrophoretic length and migration of erythrocytes from the DIC+saline and DIC+lymph groups were significantly slower than the control group. Blood relative viscosity, Hct, ESR, and electrophoretic time of erythrocytes were significantly increased in the DIC+lymph group compared to the control group. Whole blood viscosity, relative viscosity and reduced viscosity were significantly lower in the DIC+lymph group than in the DIC+saline group, and erythrocyte deformability index was also significantly higher than in the DIC+saline and control groups. These results suggest that exogenous normal lymph could markedly improve the acute microcirculation disturbance and the abnormal hemorheological properties in rats with DIC induced by Dextran 500.

Changes in erythrocyte aggregation and deformability in diabetes mellitus: a brief review.

Diabetes mellitus (DM) is a metabolic disorder characterized by varying or persistent hyperglycemia either due to insufficient production of insulin by pancreas or improper utilization of the glucose. Erythrocytes remain in hyperglycemic environment throughout their life span and thus are subjected to series of compositional changes, which in turn affect their flow properties through alteration of deformation at individual level and aggregation at collective level. This brief review summarizes the changes in biochemical parameters primarily contributing to the erythrocyte deformability and aggregation as measured by various techniques, of blood samples obtained from diabetic subjects. The significant changes in erythrocyte aggregation and deformability, in comparison with that of control subjects show the relevance of these measurements. These changes are further supported by in vivo observations of blood flow through microvessels. Finally the relevance of these in combination with other clinical parameters is suggested.

Estudo da deformabilidade eritrocitária através da ectacitometria / Study of erythrocyte deformability through ecktacytrometry

A deformabilidade eritrocitária foi estudada através da ectacitometria em uma série de pacientes portadores de esferocitose hereditária e de anemia falciforme e, comparados com os achados de indivíduos normais. A ectacitometria foi realizada no aparelho LORCA (Laser assisted rotational cell analyser - R & R Mechatronics, Holanda). Observamos diminuiçäo da deformmbilidade celular, medida através do índice de elongaçäo (ou de deformabilidade) em todos os pacientes portadores de esferocitose hereditária e de anemia falciforme. O grau de diminuiçäo da deformabilidade esteve relacionado à maior gravidade clínica, havendo correlaçäo com a porcentagem de células microcíticas e hiperdensas, verificado na esferocitose hereditária e também na anemia falciforme. A perda de material da membrana, com consequente alteraçäo da geometrial celular, desidrataçäo celular e aumento da viscosidade citoplasmática, concorrem para a diminuiçäo da deformabilidade observada na esferocitose hereditária. Na anemia falciforme a diminuiçäo da deformabilidade está relacionada ao aumento da densidade celular, secundária às características da hemoglobina S, à desidrataçäo celular e a danos da membrana eritrocitária

Estudo da deformabilidade da membrana da hemacia com a pinca optica / Erythrocyte membrane deformability study with of the \"optical tweezer\"

A pinca optica, baseada na tecnica de transferencia de momentum de fotons para capturar e manipular particulas biologicas, foi desenvolvida por A. Ashkin et al. em 1987. Desde entao, ela tem sido utilizada em estudos de genetica molecular, fertilizacao assistida, dentre outros. Neste trabalho, utilizamos a pinca optica para estudar a deformabilidade da membrana da hemacia, com o auxilio de um laser Nd:YAG, cujo feixe e focalizado num microscopio Olympus com um aumento de ate 100 vezes. A hemacia, na sua funcao de captar o oxigenio dos pulmoes e leva-lo para todas as celulas atraves da hemoglobina, percorre todos os vasos sanguineos do organismo por aproximadamente 500.000 vezes, durante sua vida media de 120 dias, atravessando uma distancia de 250km...

Haemorheological behaviour of erythrocytes & risk factor profile in patients suffering from Waldenström's macroglobulinaemia.

The plasma viscosity, haematocrit, and erythrocyte aggregation and deformability of blood samples of patients of Waldenström's macroglobulinaemia were measured by capillary viscometer, microcentrifuge, Myrenne aggregometer and filtrometer respectively and correlated with the serum IgM concentrations. The observed increase in plasma viscosity and erythrocyte aggregation and decrease in their deformability were attributed to the increase in the concentration of IgM. Haematocrit was also decreased compared to normal subjects. Based on these parameters a haemorheological risk factor profile was developed and an overall risk factor calculated. An increase in the risk factor in these patients was observed. The haemorheological profile and the calculated risk factors not only help in establishing the inter-relationship of these parameters in the disease state but also to evaluate the severity of the disease.

Malaria protection in hereditary ovalocytosis: relation to red cell deformability, red cell parameters and degree of ovalocytosis.

In the culture of red cells with Plasmodium falciparum, erythrocytes from both Thai patients and subjects (patient's parents) with hereditary ovalocytosis have a protective effect against malarial infection. High percentage of ovalocyte (75-100%) was found in patients whereas their parents had lower percentage (25-50%). Invasion index (II) and multiplication ratio (MR) of P. falciparum in these abnormal red cells from the patients were significantly decreased as compared to those in normal red cells (patients: II = 1.52 +/- 0.91, MR = 8.83 +/- 6.73; normal subjects: II = 4.45 +/- 1.51, MR = 25.23 +/- 6.25). This suggests that the red cells from these patients had significant degree of malaria protection. The significant protection was also shown in red cells from the parent group (II = 1.86 +/- 0.81, MR = 15.69 +/- 3.50). Although the parents had lower ovalocyte percentage, degree of protection against malaria parasite was as effective as those found in patients with high ovalocytic red cells. This has been confirmed by statistical analysis showing nonsignificant difference in II value between the two groups. In contrast, red cells of both groups had poor deformability (deformability index, DI) as compared to the normal group. No statistically different DI values were demonstrated between the two. This indicates that poorly deformable red cells, not their ovalocytic shape, make a significant contribution to limitation of malaria parasite invasion. The MR values in patients were less than those found in the parent group but statistical analysis showed no significant difference. Reduced MR values were found with increased numbers of microcytic, hyperchromic and hypochromic red cells in patients.

Viscoelasticidad compleja de los eritrocitos por difractometría láser / Complex viscoelasticity of erythrocyte by laser difractometry

El objetivo de este estudio fue investigar las propiedades reológicas de los glóbulos rojos sometidos a tensiones pulsantes (reología completa), es decir, en condiciones más próximas a las fisiológicas. La reología compleja demostró su alta sensibilidad para detectar anormalidades estructurales en cuerpos viscoelásticos, tales como sangre o eritrocitos. En este trabajo, las propiedades viscoelásticas complejas eritrocitarias fueron evaluadas con un Erotrodefórmetro, construido en este laboratorio, el cual aplica el método difractométrico en suspensiones de glóbulos rojos cizalladas. Tensiones de corte sinusoidales de frecuencia y amplitud controladas, son aplicadas a la suspensión celular. La elongación de los eritrocitos sigue las variaciones de la tensión, pero con un desfasaje angular Ù que es función de la frecuencia y de las propiedades reológicas de las células. Las variaciones de elongación se reproducen en el patrón de difracción laser y son fotométricamente medidas, digitalizadas y almacenadas para su posterior procesamiento. El procesamiento numérico de los datos experimentales conduce a la evaluación de los parámetros viscoelásticos complejos (Ù, n', n", G', G"). Los resultados obtenidos demuestran que la ektacitometría es un excelente método para analizar la reología compleja eritrocitaria y puede ser aplicado con éxito en Hemorreología Clínica para detectar anormalidades celulares patológicas

Erythrocyte deformability in chronic renal failure

Red blood cell [RBC] deformability [DEF] was measured in twenty patients with end stage renal failure [ESRF] before being dialyzed and in eighteen of them after a single session dialysis [nine patients received hemodialysis and the other nine patients received peritoneal dialysis]. RBCDEF was measured by means of a modified nucleopore filter method. Low RBC DEF was found in ESRF patients when compared to that of the control group. Although significant improvement of RBC DEF occurred with a single dialysis session, yet RBC DEF was significantly lower than of the control group. A statistically significant correlation was found between reduced RBC DEF and serum creatinine level in the patients with ESRF and no significant correlation was found between RBC DEF and blood urea level in uremic patients. Both modalities of dialysis can improve RBC DEF in ESRF patients

Influence of cholesterol-enrichment under in vivo and in vitro conditions on the erythrocyte membrane lipids and its deformability.

The cholesterol feeding in rabbits leads to an increase in the levels of cholesterol and phospholipids in plasma and erythrocytes. The increases in cholesterol (C) level is more than that of phospholipids (P) thereby resulting in increase of C/P ratio. The levels of phosphatidylcholine and sphingomyelin are increased in plasma and that of phosphatidylcholine in erythrocytes. Under in vitro conditions the incubation of normal human erythrocytes in cholesterol-enriched plasma (CEP) leads to increase in the cholesterol level, whereas there is no change in phospholipid composition. The deformability of cholesterol-enriched erythrocytes, as measured by their passage time through micropore membranes, under in vivo and in vitro conditions, is significantly decreased.