Erytrocyte membrane anionic charge in type 2 diabetic patients with retinopathy

Assessment of Microcirculation and Microrheological Parameters of Blood in Patients With Type 2 Diabetes Mellitus Using Biophotonics Techniques

In this study, the parameters of blood microcirculation and microrheology were measured using the methods of laser aggregometry and optical tweezers in vitro, as well as the method of digital capillaroscopy in vivo. It was shown that in patients suffering from type 2 diabetes mellitus, an increase in the number of RBC aggregates passing through the narrow capillaries leads to a significant decrease in the velocity of the capillary blood flow, which can be explained by the increased viscosity of the whole blood and decreased deformability of RBCs. Also, for the group of patients, a statistically significant increase in the rate of RBC aggregation and the hydrodynamic strength of aggregates, RBC aggregation and disaggregation forces were observed compared to the control group. We have demonstrated the possibility of using these methods to assess changes in microrheological and microcirculatory parameters of the blood.

Erythrocytes: Central Actors in Multiple Scenes of Atherosclerosis

The development and progression of atherosclerosis (ATH) involves lipid accumulation, oxidative stress and both vascular and blood cell dysfunction. Erythrocytes, the main circulating cells in the body, exert determinant roles in the gas transport between tissues. Erythrocytes have long been considered as simple bystanders in cardiovascular diseases, including ATH. This review highlights recent knowledge concerning the role of erythrocytes being more than just passive gas carriers, as potent contributors to atherosclerotic plaque progression. Erythrocyte physiology and ATH pathology is first described. Then, a specific chapter delineates the numerous links between erythrocytes and atherogenesis. In particular, we discuss the impact of extravasated erythrocytes in plaque iron homeostasis with potential pathological consequences. Hyperglycaemia is recognised as a significant aggravating contributor to the development of ATH. Then, a special focus is made on glycoxidative modifications of erythrocytes and their role in ATH. This chapter includes recent data proposing glycoxidised erythrocytes as putative contributors to enhanced atherothrombosis in diabetic patients.

Red blood cell aggregation, disaggregation and aggregate morphology in autologous plasma and serum in diabetic foot disease

BACKGROUND

Diabetes mellitus is frequently associated with microcirculation pathology and hemorheological disorders.

METHODS

24 patients with diabetic foot and 22 healthy subjects were recruited. RBC aggregation, disaggregation and morphology of aggregates were determined in autologous plasma and serum.

RESULTS

The RBC aggregation in patients with diabetic foot increased in autologous plasma and serum. Increased red blood cell aggregate strength in these patients was observed only in autologous plasma. Microscopic images of RBC aggregates of patients with diabetic foot show the formation of pathologic globular structures of aggregates in autologous plasma and serum.

CONCLUSION

The RBC aggregation in autologous plasma and autologous serum in patients with diabetic foot is significantly higher than in healthy subjects. Increase in strength of RBC aggregates in diabetic foot patients was observed only in autologous plasma. The microscopic images of RBC aggregates in patients with diabetic foot indicate the formation of globular (pathologic) structures of aggregates in autologous plasma and serum. The differences in the morphology of RBC aggregates in autologous plasma and serum between healthy subjects and diabetic foot patients, obtained by microscopic image analysis with high magnification light microscope, can be used as an additional diagnostic tool in medical practice.

Potential Diagnostic Hemorheological Indexes for Chronic Kidney Disease in Patients With Type 2 Diabetes

Many studies have demonstrated that an alteration in hemorheological properties is closely correlated with diabetic microcirculatory diseases. However, most of these studies have been limited to animal studies or used a small number of clinical samples, due to a lack of effective point-of-care (POC) devices to measure such properties within clinical environments. Owing to recent developments in microfluidic technology, several hemorheological POC devices have been designed that allow for the possibility of conducting extensive clinical studies using hemorheological measurements. Here, we reviewed recent clinical studies of diabetic kidney disease (DKD) associated with hemorheological parameters. We found that RBC deformability alone did not show a significant difference according to the degree of DKD, whereas critical shear stress (CSS) was found to be closely related to the ratio of albumin to creatinine and glomerular filtration rate. We also reviewed studies that alteration of hemorheological properties are associated with the development of DKD, which showed that CSS could be considered as a potential index to diagnose other diabetic complications as well as DKD.

Extracellular matrix, gap junctions, and retinal vascular homeostasis in diabetic retinopathy

The vascular basement membrane (BM) contains extracellular matrix (ECM) proteins that assemble in a highly organized manner to form a supportive substratum for cell attachment facilitating myriad functions that are vital to cell survival and overall retinal homeostasis. The BM provides a microenvironment in which bidirectional signaling through integrins regulates cell attachment, turnover, and functionality. In diabetic retinopathy, the BM undergoes profound structural and functional changes, and recent studies have brought to light the implications of such changes. Thickened vascular BM in the retinal capillaries actively participate in the development and progression of characteristic changes associated with diabetic retinopathy. High glucose (HG)-induced compromised cell-cell communication via gap junctions (GJ) in retinal vascular cells may disrupt homeostasis in the retinal microenvironment. In this review, the role of altered ECM synthesis, compromised GJ activity, and disturbed retinal homeostasis in the development of retinal vascular lesions in diabetic retinopathy are discussed.

Red blood cell count as an indicator of microvascular complications in Chinese patients with type 2 diabetes mellitus

BACKGROUND

Rheological disorders of red blood cells (RBC) and decreased RBC deformability have been involved in the development of diabetic microangiopathy. However, few studies have evaluated the association of RBC count with microvascular complications in patients with type 2 diabetes mellitus (T2DM). The purpose of this study was to investigate the association of RBC count with microvascular complications in patients with T2DM.

METHODS

This study involved 369 patients with T2DM: 243 with one or more microvascular complications and 126 without microvascular complications. Anticoagulated blood was collected and analyzed in an automated blood cell counter. The presence of risk factors for microvascular complications was determined.

RESULTS

The proportion of patients with microvascular complications increased as the RBC count decreased (P < 0.001). After adjustment for known risk factors for microvascular complications by logistic regression analysis, lower quartiles of RBC count were associated with a higher risk of microvascular complications compared with the reference group composed of the highest quartile (first quartile, odds ratio 4.98, 95% confidence interval 1.54-6.19, P = 0.008; second quartile, odds ratio 3.21, 95% confidence interval 1.17-5.28, P = 0.024).

CONCLUSION

A decreased RBC count is associated with microvascular complications in Chinese patients with T2DM. The RBC count is a potential marker to improve further the ability to identify diabetic patients at high risk of microvascular complications.

Urinary markers of glomerular injury in diabetic nephropathy

Diabetic nephropathy, the leading cause of renal failure worldwide, affects approximately one-third of all people with diabetes. Microalbuminuria is considered the first sign and the best predictor of progression to renal failure and cardiovascular events. However, albuminuria has several limitations. Therefore, earlier, more sensitive and specific biomarkers with greater predictability are needed. The aim of this paper is to discuss the current literature on biomarkers of glomerular injury that have been implicated in diabetic kidney disease.

Role of the cell wall microenvironment in expression of a heterologous SpaP-S1 fusion protein by Streptococcus gordonii

The charge density in the cell wall microenvironment of Gram-positive bacteria is believed to influence the expression of heterologous proteins. To test this, the expression of a SpaP-S1 fusion protein, consisting of the surface protein SpaP of Streptococcus mutans and a pertussis toxin S1 fragment, was studied in the live vaccine candidate bacterium Streptococcus gordonii. Results showed that the parent strain PM14 expressed very low levels of SpaP-S1. By comparison, the dlt mutant strain, which has a mutation in the dlt operon preventing d-alanylation of the cell wall lipoteichoic acids, and another mutant strain, OB219(pPM14), which lacks the LPXTG major surface proteins SspA and SspB, expressed more SpaP-S1 than the parent. Both the dlt mutant and the OB219(pPM14) strain had a more negatively charged cell surface than PM14, suggesting that the negative charged cell wall played a role in the increase in SpaP-S1 production. Accordingly, the addition of Ca(2+), Mg(2+), and K(+), presumably increasing the positive charge of the cell wall, led to a reduction in SpaP-S1 production, while the addition of bicarbonate resulted in an increase in SpaP-S1 production. The level of SpaP-S1 production could be correlated with the level of PrsA, a peptidyl-prolyl cis/trans isomerase, in the cells. PrsA expression appears to be regulated by the cell envelope stress two-component regulatory system LiaSR. The results collectively indicate that the charge density of the cell wall microenvironment can modulate heterologous SpaP-S1 protein expression in S. gordonii and that this modulation is mediated by the level of PrsA, whose expression is regulated by the LiaSR two-component regulatory system.

Association between erythrocyte Na+K+-ATPase activity and some blood lipids in type 1 diabetic patients from Lagos, Nigeria

BACKGROUND

Altered levels of erythrocyte Na+K+-ATPase, atherogenic and anti-atherogenic lipid metabolites have been implicated in diabetic complications but their pattern of interactions remains poorly understood.This study evaluated this relationship in Nigerian patients with Type 1 diabetes mellitus.

METHODS

A total of 34 consented Type 1 diabetic patients and age -matched 27 non-diabetic controls were enrolled. Fasting plasma levels of total cholesterol, triglycerides and HDL-cholesterol were determined spectrophotometrically and LDL-cholesterol estimated using Friedewald formula. Total protein content and Na+K+-ATPase activity were also determined spectrophotometrically from ghost erythrocyte membrane prepared by osmotic lysis.

RESULTS

Results indicate significant (P < 0.05) reduction in Na+K+-ATPase activity in the Type 1 diabetic patients (0.38 +/- 0.08 vs. 0.59 +/- 0.07 microM Pi/mgprotein/h) compared to the control but with greater reduction in the diabetic subgroup with poor glycemic control (n = 20) and in whom cases of hypercholesterolemia (8.8%), hypertriglyceridemia (2.9%) and elevated LDL-cholesterol (5.9% each) were found. Correlation analyses further revealed significant (P < 0.05) inverse correlations [r = -(0.708-0.797] between all the atherogenic lipid metabolites measured and Na+K+-ATPase in this subgroup contrary to group with good glycemic control or non-diabetic subjects in which significant (P < 0.05) Na+K+-ATPase and HDL-C association were found (r = 0.427 - 0.489). The Na+K+-ATPase from the diabetic patients also exhibited increased sensitivity to digoxin and alterations in kinetic constants Vmax and Km determined by glycemic status of the patients.

CONCLUSION

It can be concluded that poor glycemic control evokes greater reduction in erythrocyte Na+K+-ATPase activity and promote enzyme-blood atherogenic lipid relationships in Type 1 diabetic Nigerian patients.