Glycated hemoglobin concentrations of red blood cells minimally increase during storage under standard blood banking conditions

Estimation of HbA1c Levels in Transfusion-Dependent Thalassemia Patients in Comparison With Normal Healthy Individuals

Introduction HbA1c values used for diagnosing and treating diabetes can be affected by factors such as red blood cell lifespan, hemolysis, red cell transfusion, and the presence of minor Hb species like HbA2 and HBF in hemoglobinopathies like sickle cell disease, homozygous HbC disease, HbSC disease, and β-thalassemia. This study aims to compare HbA1c levels in transfusion-dependent thalassemia (TDT) patients and healthy individuals. Materials and methods This is a cross-sectional comparative study. This study comprises two population groups. The first group includes 35 TDT patients and the second group consists of 35 non-thalassemic individuals who were matched for age (±1 year), gender, and BMI (±1 kg/m2). The patients were selected from the pediatric outpatient department (OPD), thalassemia ward in the pediatric department, and medicine OPD. Written informed consent/assent was obtained from the participants. A 3 ml fasting venous blood sample for fasting blood sugar (FBS), HbA1c, and complete blood count (CBC) values was obtained in ethylenediaminetetraacetic acid (EDTA) vials on the scheduled blood transfusion day (pretransfusion samples). Samples were then sent to an in-house accredited lab for testing and analysis. HbA1c was performed using the high-performance liquid chromatography (HPLC) technique. Data was compared using a t-test. Qualitative parameters were compared between groups by X2 square analyses. A multivariate linear regression model was used to explore the independent contribution of an individual predictor to HbA1c variability. Results In the study, 85.7% of patients with TDT had HbA1c levels in the diabetic range (>6.4%). In comparison, none of the control group patients had HbA1c values in the diabetic range. The mean HbA1c level was 6.94% in TDT cases and 5.3% in the control group, which was statistically significant (p < 0.001). Elevated FBS levels in the prediabetic range (>100 mg/dl, <126mg/dl) were observed in 25.7% TDT cases. All 35 controls had normal FBS levels (<100 mg/dl). No significant difference was found in FBS levels between cases (92.97 (±9.141) mg/dL) and controls (89.20 (±7.584) mg/dL) (p = 0.065). However moderately positive correlation exists between FBS and HbA1C (r =.470, p = 0.004) and between age and HbA1C (r = 0.335, p = 0.049). Conclusions The use of HbA1c as a screening tool for diabetes mellitus (DM) or assessment of glycemic control is inappropriate in TDT patients. The levels could be falsely elevated, as we found out in our study. In conditions where there is a mismatch between HbA1c and FBS levels, as seen in TDT patients, plasma glucose criteria should be used to diagnose diabetes. It is advised to use alternative indices such as fructosamine levels, glycated albumin, and continuous glucose monitoring.

Storage of packed red blood cells impairs an inherent coagulation property of erythrocytes

Storage of packed red blood cells is associated with changes in erythrocytes that over time increasingly impair cellular function and potentially contribute to adverse effects associated with blood transfusion. Exposure of phosphatidylserine at the outer membrane leaflet of erythrocytes and shedding of microvesicles (MVs) during packed red blood cell storage are alterations assumed to increase the risk of prothrombotic events in recipients. Here, we used rotational thromboelastometry to study the coagulation process in blood samples with erythrocytes from stored PRBCs reconstituted with freshly prepared platelet-rich plasma. We explored the influence of following effects on the coagulation process: 1) PRBC storage duration, 2) differences between erythrocytes from stored PRBCs compared to freshly drawn erythrocytes, and 3) the contribution of added MVs. Interestingly, despite of a higher fraction of PS-positive cells, erythrocytes from PRBCs stored for 6 weeks revealed longer clotting times than samples with erythrocytes stored for 2 or 4 weeks. Further, clotting times and clot formation times were considerably increased in samples reconstituted with erythrocytes from stored PRBCs as compared to fresh erythrocytes. Moreover, MVs added to reconstituted samples elicited only comparably small and ambiguous effects on coagulation. Thus, this study provides no evidence for an amplified clotting process from prolonged storage of PRBCs but on the contrary implicates a loss of function, which may be of clinical significance in massive transfusion. Our observations add to the increasing body of evidence viewing erythrocytes as active players in the clotting process.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Packed red blood cells inhibit T-cell activation via ROS-dependent signaling pathways

Numerous observations indicate that red blood cells (RBCs) affect T-cell activation and proliferation. We have studied effects of packed RBCs (PRBCs) on T-cell receptor (TCR) signaling and the molecular mechanisms whereby (P)RBCs modulate T-cell activation. In line with previous reports, PRBCs attenuated the expression of T-cell activation markers CD25 and CD69 upon costimulation via CD3/CD28. In addition, T-cell proliferation and cytokine expression were markedly reduced when T-cells were stimulated in the presence of PRBCs. Inhibitory activity of PRBCs required direct cell–cell contact and intact PRBCs. The production of activation-induced cellular reactive oxygen species, which act as second messengers in T-cells, was completely abrogated to levels of unstimulated T-cells in the presence of PRBCs. Phosphorylation of the TCR-related zeta chain and thus proximal TCR signal transduction was unaffected by PRBCs, ruling out mechanisms based on secreted factors and steric interaction restrictions. In large part, downstream signaling events requiring reactive oxygen species for full functionality were affected, as confirmed by an untargeted MS-based phosphoproteomics approach. PRBCs inhibited T-cell activation more efficiently than treatment with 1 mM of the antioxidant N-acetyl cysteine. Taken together, our data imply that inflammation-related radical reactions are modulated by PRBCs. These immunomodulating effects may be responsible for clinical observations associated with transfusion of PRBCs.

HbA1c level decreases in iron deficiency anemia

BACKGROUND

Hemoglobin A1c (HbA1c) is the major form of glycosylated hemoglobin. There are conflicting data on changes in HbA1c levels in patients with iron deficiency anemia (IDA). The present study aimed to investigate the effects of HbA1c levels in the presence of IDA, the effects of iron treatment on HbA1c levels, as well as the relationship between the severity of anemia and HbA1c levels in patients without diabetes.

DESIGN AND METHODS

A total of 263 patients without diabetes mellitus (DM) who were admitted to Cukurova University, Faculty of Medicine, Department of Endocrinology and Hematology or who were followed up in this clinic and diagnosed as having IDA were included in the study. A total of 131 patients had IDA. The control group comprised 132 age-matched and sex-matched healthy individuals.

RESULTS

The mean HbA1c level was significantly lower in the group with IDA (5.4%) than in the healthy control group (5.9%; p < 0.05). When the patients were divided into three groups according to the severity of anemia through Hb levels, HbA1c levels were observed to decrease as the severity of the anemia increased (5.5%, 5.4%, and 5%, respectively; p > 0.05). The HbA1c levels of the patients with IDA were higher after iron therapy (from 5.4 ± 0.5 to 5.5 ± 0.3; p = 0.057). The mean hemoglobin (Hb), hematocrit (Hct), mean cell volume (MCV), mean corpusculer hemoglobin (MCH), and ferritin values also increased after iron therapy (p < 0.05).

CONCLUSION

The study results showed that IDA was associated with low HbA1c levels, and increased after iron therapy. Based on the study findings, it is necessary to consider the possible effects of IDA on HbA1c levels.