The effect of anti-coagulants on the osmotic fragility of erythrocytes in the yak (Poephagus grunniens)

Uncoupling Thermotolerance and Growth Performance in Chinook Salmon: Blood Biochemistry and Immune Capacity

Ocean warming and extreme sea surface temperature anomalies are threatening wild and domesticated fish stocks in various regions. Understanding mechanisms for thermotolerance and processes associated with divergent growth performance is key to the future success of aquaculture and fisheries management. Herein, we exposed Chinook salmon (Oncorhynchus tshawytscha) to environmentally relevant water temperatures (19–20 °C) approaching their upper physiological limit for three months and sought to identify blood biomarkers associated with thermal stress and resilience. In parallel, blood biochemical associations with growth performance were also investigated. Temperature stress-activated leukocyte apoptosis induced a minor immune response, and influenced blood ion profiles indicative of osmoregulatory perturbation, regardless of how well fish grew. Conversely, fish displaying poor growth performance irrespective of temperature exhibited numerous biomarker shifts including haematology indices, cellular-based enzyme activities, and blood clinical chemistries associated with malnutrition and disturbances in energy metabolism, endocrine functioning, immunocompetence, redox status, and osmoregulation. Findings provide insight into mechanisms of stress tolerance and compromised growth potential. Biochemical phenotypes associated with growth performance and health can potentially be used to improve selective breeding strategies.

Effect of anticoagulants on farmed giant kokopu, Galaxias argenteus (Gmelin 1789) haematological parameters and erythrocyte fragility

We sought to determine a compatible anticoagulant for routine haematological and physiological assessments with giant kokopu (Galaxias argenteus), an endemic New Zealand fish. We observed that blood treated with lithium heparin (LH) rapidly coagulated and haemolysed, making it unsuitable for G. argenteus. Dipotassium ethylenediaminetetraacetic acid (K₂ EDTA) and trisodium citrate (citrate) effectively prevented blood coagulation. K₂ EDTA-treated erythrocytes exhibited the least mean haemolysis and mean corpuscular fragility. Further studies into prolonged storage effects of citrate and K₂ EDTA are recommended to find a compatible anticoagulant for use with G. argenteus blood.

Red Blood Cells: Tethering, Vesiculation, and Disease in Micro-Vascular Flow

The red blood cell has become implicated in the progression of a range of diseases; mechanisms by which red cells are involved appear to include the transport of inflammatory species via red cell-derived vesicles. We review this role of RBCs in diseases such as diabetes mellitus, sickle cell anemia, polycythemia vera, central retinal vein occlusion, Gaucher disease, atherosclerosis, and myeloproliferative neoplasms. We propose a possibly unifying, and novel, paradigm for the inducement of RBC vesiculation during vascular flow of red cells adhered to the vascular endothelium as well as to the red pulp of the spleen. Indeed, we review the evidence for this hypothesis that links physiological conditions favoring both vesiculation and enhanced RBC adhesion and demonstrate the veracity of this hypothesis by way of a specific example occurring in splenic flow which we argue has various renderings in a wide range of vascular flows, in particular microvascular flows. We provide a mechanistic basis for membrane loss and the formation of lysed red blood cells in the spleen that may mediate their turnover. Our detailed explanation for this example also makes clear what features of red cell deformability are involved in the vesiculation process and hence require quantification and a new form of quantitative indexing.

Fluorescent Heme Degradation Products Are Biomarkers of Oxidative Stress and Linked to Impaired Membrane Integrity in Avian Red Blood Cells

Oxidative stress is generally understood to be an important mediator of life-history traits, yet the specific relationships between oxidative stress and life-history traits have been difficult to describe because there is often a lack of covariation among biomarkers of oxidative stress. For instance, although oxidative damage to red blood cell (RBC) membranes can lead to pathological conditions (i.e., anemia), in some cases there is not a clear relationship between lipid oxidation and RBC membrane resistance to pro-oxidants. Alternatively, oxidative damage to hemoglobin may be an indirect mechanism contributing to RBC membrane damage. To better understand the mechanisms contributing to oxidative damage and probe new approaches to measuring oxidative stress, we used a series of in vitro and in vivo procedures in zebra finches (Taeniopygia guttata) to explore (1) whether avian RBCs exposed to a pro-oxidant generate fluorescent heme degradation products (HDPs), (2) whether HDPs interact with RBC membranes, and (3) whether HDPs are linked to impaired RBC integrity. We found that finch RBCs exposed in vitro to hydrogen peroxide produced fluorescent HDPs and HDPs associated with RBC membranes. Exposure to hydrogen peroxide also caused a reduction in hemoglobin and an increase in percent methemoglobin (a hemoglobin oxidation product), further indicating hemoglobin degradation. Moreover, HDP fluorescence correlated with impaired membrane integrity and erythrocyte osmotic fragility in vivo. This study suggests that reactive oxygen species may indirectly impair RBC membrane integrity via hemoglobin degradation products that associate with RBC membranes and that HDPs may be an inexpensive and logistically simple tool for measuring oxidative stress.

Red blood cell osmotic fragility in healthy loggerhead and green sea turtles

Loggerhead (Caretta caretta; Cc) and green sea (Chelonia mydas; Cm) turtles admitted to rehabilitation facilities may require blood transfusions for supportive treatment of disorders resulting in life-threatening anemia, but, considering the unique erythrocyte chemistry of sea turtles, standardized donor red blood cell (RBC) storage protocols have not been established. Prolonged cold storage and the effects of various anticoagulant-preservative solutions have been associated with increased RBC osmotic fragility across a broad range of species. Increased RBC fragility in stored RBC products has been associated with acute transfusion reactions. The osmotic fragility test is used to measure erythrocyte resistance to hemolysis while being exposed to a series of dilutions of a saline solution. We obtained baseline measurements for osmotic fragility in healthy Cc and Cm. Osmotic fragility testing was performed on samples from 10 Cc to 10 Cm. Fifty percent (50%) RBC hemolysis was identified at a mean NaCl concentration of 0.38% in both species. Results of our study will help guide future studies evaluating optimal storage solutions for sea turtle blood products.

Tethering, evagination, and vesiculation via cell-cell interactions in microvascular flow

Vesiculation is a ubiquitous process undergone by most cell types and serves a variety of vital cell functions; vesiculation from erythrocytes, in particular, is a well-known example and constitutes a self-protection mechanism against premature clearance, inter alia. Herein, we explore a paradigm that red blood cell derived vesicles may form within the microvascular, in intense shear flow, where cells become adhered to either other cells or the extracellular matrix, by forming tethers or an evagination. Adherence may be enhanced, or caused, by diseased states or chemical anomalies as are discussed herein. The mechanisms for such processes are detailed via numerical simulations that are patterned directly from video-recorded cell microflow within the splenic venous sinus (MacDonald et al. 1987), as included, e.g., as Supplementary Material. The mechanisms uncovered highlight the necessity of accounting for remodeling of the erythrocyte's membrane skeleton and, specifically, for the time scales associated with that process that is an integral part of cell deformation. In this way, the analysis provides pointed, and vital, insights into the notion of what the, often used phrase, cell deformability actually entails in a more holistic manner. The analysis also details what data are required to make further quantitative descriptions possible and suggests experimental pathways for acquiring such.

Na2EDTA anticoagulant impaired blood samples from the teleost Piaractus mesopotamicus

Abstract: The present study aimed to evaluate the effects of Na heparin and Na2EDTA on blood of Piaractus mesopotamicus (360.7±42.4g, 26.4±1.0cm). Twenty fishes were sampled in two experiment trials, ten for erythrocyte fragility analysis and ten for hematologic and plasma biochemical study. The blood collected by venous-caudal puncture was fractioned and stored in anticoagulants solution: Na2EDTA 10%, Na2EDTA 3%, Na heparin 5000 IU and Na heparin 100 IU. Plasmatic levels of calcium presented in the Na2EDTA stored samples were about 80% lower than both heparin groups. Blood samples of P. mesopotamicus stored with Na2EDTA demonstrated increase in the hematocrit and MCV, and decrease in MCHC. The dose-response effect was observed in this study. The results are reinforced by the higher levels of plasmatic protein and hemolysis presented in the Na2EDTA 10% stored blood, confirming the deleterious effect of this anticoagulant treatment on the quality of blood samples. Na2EDTA is not indicated to store P. mesopotamicus blood samples, but sodium heparin at 100 IU is the most recommended anticoagulant, since this treatment presented the lower rate of alterations in the stored blood.