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Oxidative stress contributes to Haemolytic Anaemia in many species including dogs and cats, as well as in humans. Red cells are exposed to a continual oxidant challenge, both endogenously from within the red cells themselves and also exogenously from other tissues, and from ingested or administered oxidants. When the oxidative challenge exceeds the antioxidant provisions of the red cell, damage occurs in the form of lipid and protein peroxidation, cytoskeletal crosslinking, oxidation of haemoglobin to methemolglobin, and precipitation of denatured sulphhaemoglobin as Heinz bodies. These deleterious sequelae produce fragile red cells with reduced lifespan, and result in poorer oxygen delivery to tissues, intravascular haemolysis, anaemia, haemoglobinuria and jaundice. A number of features increase the risk of oxidant damage in dogs and cats. Thus dog red cells have low levels of the antioxidant enzyme catalase. Cat haemoglobin has at least four times as many readily oxidizable thiol residues compared to most species, whilst their hepatic capacity for glucuronidation is much reduced, which can result in greater accumulation of oxidants. Like humans, both species may also be exposed to excess oxidants from systemic diseases such as diabetes mellitus, hepatic lipidosis, hypophosphatemia and neoplasias. Iatrogenic oxidants include drugs such as acetaminophen and other non-steroidal anti-inflammatory compounds. Ingested toxins include heavy metals, particularly important in dogs with their increased propensity for scavenging. Ingestion of feeds containing products from Allium species of plants has also long been associated with red cell oxidative damage and Heinz body formation in both dogs and cats. Though less common than in humans, there are occasional congenital enzyme deficiencies which reduce the enzymatic oxidant defence of the red cells in these species. Treatment usually relies on removal of the oxidant challenge or support against the resulting anaemia. Specific antioxidants currently lack efficacy but analogy with human medicine suggests that a range possible antioxidants may be potentially beneficial.
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Integrave Journal of Veterinary Biosciences
Volume 3 Issue 3
Integr J Vet Biosci, Volume 3(3): 1–5, 2019
Research Open
Review Article
Oxidative Stress and Haemolytic Anaemia In Dogs and
Cats: A Comparative Approach
Gibson JS1*, Wadud R1, Lu DCY1, Brewin JN2 and Rees DC2
1Department of Veterinary Medicine, Madingley Road, Cambridge, UK
2Department of Paediatric Haematology, King’s College Hospital, London, UK
*Corresponding author: John S. Gibson, Department of Veterinary Medicine, Madingley Road, Cambridge, CB3 0ES, UK; E-mail:
Received: October 15, 2019; Accepted: October 23, 2019; Published: October 31, 2019
Oxidative stress contributes to Haemolytic Anaemia in many species including dogs and cats, as well as in humans. Red cells are exposed to a continual
oxidant challenge, both endogenously from within the red cells themselves and also exogenously from other tissues, and from ingested or administered
oxidants. When the oxidative challenge exceeds the antioxidant provisions of the red cell, damage occurs in the form of lipid and protein peroxidation,
cytoskeletal crosslinking, oxidation of haemoglobin to methemolglobin, and precipitation of denatured sulphhaemoglobin as Heinz bodies. These
deleterious sequelae produce fragile red cells with reduced lifespan, and result in poorer oxygen delivery to tissues, intravascular haemolysis, anaemia,
haemoglobinuria and jaundice. A number of features increase the risk of oxidant damage in dogs and cats. Thus dog red cells have low levels of the
antioxidant enzyme catalase. Cat haemoglobin has at least four times as many readily oxidizable thiol residues compared to most species, whilst their
hepatic capacity for glucuronidation is much reduced, which can result in greater accumulation of oxidants. Like humans, both species may also be
exposed to excess oxidants from systemic diseases such as diabetes mellitus, hepatic lipidosis, hypophosphatemia and neoplasias. Iatrogenic oxidants
include drugs such as acetaminophen and other non-steroidal anti-inammatory compounds. Ingested toxins include heavy metals, particularly
important in dogs with their increased propensity for scavenging. Ingestion of feeds containing products from Allium species of plants has also long been
associated with red cell oxidative damage and Heinz body formation in both dogs and cats. Though less common than in humans, there are occasional
congenital enzyme deciencies which reduce the enzymatic oxidant defence of the red cells in these species. Treatment usually relies on removal of the
oxidant challenge or support against the resulting anaemia. Specic antioxidants currently lack ecacy but analogy with human medicine suggests that
a range possible antioxidants may be potentially benecial.
Key words: Antioxidant Defence, Dogs and Cats, Haemolytic Anaemia, Oxidative Stress
Red cells occupy a unique position within the vertebrate body.
When mature, they are enucleated and lack cytoplasmic organelles
[1]. As such, they are therefore unable to carry out ribosomal protein
synthesis or mitochondrial oxidative phosphorylation. ey are
dependent upon glycolysis (or the Emden-Meyerho pathway) for
whatever ATP supply is required to maintain their osmotic integrity,
through various ion pumps, and for other energy requiring events,
like synthesis of reduced glutathione, one of their main antioxidant
defences [2, 3]. All vertebrate red cells have the main task of carriage
of blood gases, oxygen from respiratory tissues and carbon dioxide
from metabolically active tissues. Notwithstanding, there are some
surprising species dierences in function, which are signicant
both physiologically and pathologically [1]. For example, most
vertebrate red cells contain high levels of K+ and low levels of Na+,
whose gradients are maintained through the functioning of the
ATP-dependent Na+/K+ pump in the red cell membrane. is pump,
together with a normally low passive “leak” to Na+ and K+ prevent
osmotic swelling which would otherwise occur through the large
cytoplasmic load of impermeable protein, especially haemoglobin
(Hb), and other molecules, notably organic phosphates [4]. By
contrast, dog and cat red cells are usually low in K+ and high in Na+.
When mature – but not during development – their red cells lack Na+/
K+ pumping capacity and rather they use combinations of Ca2+ pumps
and Na+/Ca2+ exchange proteins to maintain osmotic equilibrium [5].
An exception is high K+-containing red cells of certain Asian breeds
for example, the Japanese Shibas and Akitas [6] which retain Na+/
K+ pumping capacity, and also high levels of the antioxidant reduced
glutathione, throughout their lifespan. ere are also other dierences
in physiology of dog and cat red cells pertinent to the subject of this
review, and which are considered later.
Dog and Cat Red Cells
In the absence of shear stress, human red cells have the classic
biconcave shape with a diameter of about 8 µm. Dog and cat red
cells have a similar appearance but are somewhat smaller, at 7 µm
and 5.5–6.3 µm, respectively [7]. Cat red cells, in particular, show a
degree of anisocytosis and also tend to lack the central pallor which
is easily recognizable in the more obviously biconcave shape of dog
and human red cells. e oxygen-carrying pigment Hb is found in all
vertebrates with the exception of a few species of Antarctic sh [8].
e latter live at subzero temperatures and thereby survive and carry
John S Gibson (2019) Oxidative stress and haemolytic anaemia in dogs and cats: a comparative approach
Integr J Vet Biosci, Volume 3(3): 2–5, 2019
out aerobic metabolism using only the additional oxygen dissolved
in plasma at these low temperatures. ere are species variations in
Hb, however. In this context, cat Hb is noticeable in having 8–10
readily oxidizable sulphydryl groups [9, 10] whilst most other species
including humans and dogs have only two main ones, represented
by the highly conserved β93 cysteines [11, 12]. Cat Hb also readily
dissociates from the usual tetrameric form to dimers [13] which have
a greater tendency for autoxidation [14]. Heinz bodies, denatured,
precipitated sulphHb, are a special feature of oxidative stress [14].
ey are also found in the circulation of healthy cats, however, at
up to 5–10 % red cells, presumably because of their greater number
of oxidative sites in Hb and impaired red cell antioxidant defence,
together with the poor ability of the non-sinusoidal feline spleen to
remove Heinz body-containing red cells [15]. Cats also have two main
Hbs A and B [9, 16]. HbA is most prevalent in domestic short- and
long-haired cats have HbA (98 %) but a few breeds have greater levels
of HbB (eg 10 % Persians and 14 % in Abyssinians, with as much as 50
% in Devon Rexs) and geographically to occur {eg [17]}. e oxygen
anity of many species is reduced by organic phosphates, especially
2,3-diphosphoglycerate (2,3-DPG or 2,3-biphosphoglycerate), but cat
HbA is less responsive to the reduction in P50 whilst HbB does not
respond at all [18, 19]. Cat red cells also have low levels of 2,3-DPG
[20] which is understandable if it has little regulatory eect on oxygen
anity. Dogs have also several Hbs and more than twelve blood
groups [21] but react like human Hb to 2,3-DPG.
Red Cell Metabolism
Mature red cells lack mitochondria and are therefore dependent
on anaerobic glycolysis for ATP synthesis [3]. Compared with
the citric acid (Kreb cycle) of aerobic respiration this is relatively
inecient, producing two molecules of ATP per glucose moiety
(compared with thirty six in mitochondrial aerobic respiration).
Glycolysis comprises ten enzymatic steps [1], although the main rate
limiting enzymes are hexokinase and pyruvate kinase, at the start and
end of the chain, respectively. In addition to ATP, the pathway also
syntheses reducing power in the form of NADH. NADH is necessary
to reduce methaemoglobin (metHb) using methaemoglobin reductase
(or cytochrome b reductase) – one of the main red cell antioxidant
defences. An o-shoot of the glycolytic pathway called the pentose
phosphate shunt (or hexose monophosphate shunt) is used to make the
reducing compound NADPH, a substrate for glutathione reductase – a
second main antioxidant enzyme – which reduces oxidised glutathione
(GSSG) back to reduced glutathione (GSH). Under normal conditions,
glycolysis uses the majority of glucose metabolised by the red cell, with
the pentose phosphate shunt accounting for only about 10 % of the
ux. Inhibition of the rst enzyme of the pentose phosphate shunt,
glucose-6-phosphate dehydrogenase, by high NADPH / NADP ratios
is responsible and this enzyme normally operates at only a low level of
its maximum capacity. Under conditions of oxidative stress, however,
as NADPH / NADP ratios fall, glucose is preferentially channelled
along the pentose phosphate shunt. Interestingly, deoxyHb which
preferentially binds to the cytoplasmic tail of the anion exchanger (or
Band 3) displaces glycolytic and other enzymes so that deoxygenated
red cells carry out more glycolysis, oxygenated ones produce more
NADPH [22, 23] providing a physiological switch to channel glucose
through one or other pathways. In addition, the red cells of some
species are less permeable to glucose, eg some sh and pigs [1, 24,
25]. In these cases, the pentose phosphate shunt pathways can be
used as an alternative to glycolysis for synthesis of ATP, metabolising
nucleosides, such as inosine and metabolites of ribose, which enter
into the distal part of the glycolytic pathway.
e third red cell metabolic pathway of note is the Rapaport-
Luebering shunt (1950s). is uses the enzyme biphosphoglycerate
mutase to produce 2,3-DPG (2,3-BPG) – apparently conned to cells
of the erythroid lineage and placental cells [26] and accounts for about
20 % of the glucose passing through glycolysis. ere is a metabolic cost
to this, as the Rapaport-Luebering shunt bypasses phosphoglycerate
kinase with the loss of one ATP of the two molecules of ATP from
metabolism of glucose. Congenital enzyme deciencies in the red
cell metabolic pathways have been well described in humans [2, 27].
Some genetic deciencies have also been described in dogs and cats
[Table 1]. Whilst oxidative threat is not the root of these conditions,
a defect in antioxidant defences will accompany the inadequacies
in glucose metabolism which underlie the loss of ATP, and which
represents the main cause of red cell instability.
Table 1. Some inherited causes of haemolytic anaemia in dogs and cats.
Catalase American foxhound, beagle [55]
Hereditary elliptocytosis Band 4,1 deciency [56]
Hereditary spherocytosis Autosomal recessive trait in chondrodysplastic
Alaskan malamute dwarf dogs
Hereditary stomatocytosis Schnauzers [57,59]
Methaemoglobin redutase Dogs (toy Alaskan Eskimo, miniature poodle,
cocker/poodle cross) and cats – domestic short
hair [60,61,62]
Osmotic fragility syndrome Abyssinian, Somali, Siamese and domestic short
hair cats [63–64]
Phosphofructokinase (PFK)
English springer spaniels, American cocker
spaniels, whippets [65–66]
Pyruvate kinase (PK)
Basenjis, Cairn terrier, West Highland white
terriers, beagles, cairn terriers, miniature
poodles, dachshunds, Chihuahus, American
Eskimo toy dogs, pugs, American Labrador
retrievers; Abyssinian, Somali and domestic
shorthaired cats [67]
Oxidative Challenge
Red cells are also subject to considerable oxidative stress
throughout their lifespan. Oxidative challenges arise from several
underlying conditions and sources [28, 29]. First, oxygen is potentially
toxic and their function as the main oxygen-carrying cell of the body
exposes them continually to the threat of oxygen damage. Whilst
in other tissues, there is always some slippage of oxygen away from
its mitochondrial function in aerobic respiration, which generates
superoxide anion and other free radicals, in red cells, the iron-
containing Hb is the major source of reactive oxygen species [29,
John S Gibson (2019) Oxidative stress and haemolytic anaemia in dogs and cats: a comparative approach
Integr J Vet Biosci, Volume 3(3): 3–5, 2019
30]. e ferrous Fe2+ in heme groups is potentially unstable and liable
to autoxidation to ferric Fe3+, generating superoxide and, through
dismutation, hydrogen peroxide [31] which may be removed by one
of the important red cell antioxidant enzymes, catalase. Heme iron
is also able to take part in the Fenton and Haber-Weiss reactions to
generate hydroxyl and other free radicals [2, 32]. Red cell NADPH
oxygenase is a further source of endogenous oxidants [28, 33]. Around
0.5–3% red cell haemoglobin is oxidized daily [34], producing a
constant source of methaemoglobin, although levels are usually kept
below 1% through the reducing action of methaemoglobin reductase
[35]. In addition, there is the threat from exogenous oxidants which
may enter the circulation from other tissues, for example following
ischaemia / reperfusion [36], or the action of xanthine oxidase on
hypoxanthine [37] or also via ingested or iatrogenic oxidants [7]. Cat
Hb more susceptible to oxidants (Harvey & Kaneko 1976), especially
feline HbB cf feline HbA. Counterintuitively, dogs with red cells
containing high levels of K+, and also high levels of the antioxidant
reduced glutathione notably Japanese breeds [38] appear more
susceptible to oxidative damage than the more common low K+ ones.
A number of systemic diseases are associated. Some of these include
diabetes mellitus, hepatic problems, hyperthyroidism (especially in
cats), neoplasia, severe hypophosphataemia (eg refeeding syndrome
in cats) and uraemic syndrome.
Oxidative red cell damage from ingestion of products from
Allium species (onions, garlic and related plants – see [39] for a list
of plants) are particularly heavily implicated in the case of dogs and
cats. Onion poisoning in dogs has been recognised since the 1930s
[40] and is due mainly to sulphur-containing organic compounds,
which give the characteristic odour of these foods [39]. ese
compounds are not destroyed by cooking or spoilage. Metabolites
particularly propylsulphides are implicated in onion-induced
oxidant damage of red cells in dogs and cats [41]. Animals probably
need to consume about 0.5 % of their body weight in onions to be
aected [42], though of course the wet weight and the concentration
of the active ingredient will be very variable between feedstus.
Cats are less frequently aected by Allium spp. toxicity because of
their dietary preferences though cases do occur, for example in ill
animals fed on human baby food [43]. Ironically, the same sulphur-
containing organic compounds which cause harm to dogs and cats
are associated with the therapeutic benets of Allium spp. in humans
[44]. Cats also have low hepatic glucuronidation capacity. ey lack
many uridine diphosphate glucuronyltransferases (UGTs) which
makes them particularly susceptible to a number of iatrogenic drugs.
ey thus have a very poor ability to metabolise compounds such
as acetaminophen and salicylic acid [45], for which there is no safe
dose. In both dog and cat, overdoses with acetaminophen leads to the
accumulation of metabolites such as p-aminophenol (PAP) in their red
cells, which lack N-acetyltransferase 2 (NAT2) to remove it. e result
is methaemoglobinaemia [46]. Overdose in other species including
humans, by comparison, is associated with hepatic toxicity induced
by the metabolite N-acetyl-p-benzoquinoneimine (NADPQI) rather
than oxidative damage to red cells. Heavy metals are also implicated
in oxidative damage to red cells, particularly in dogs. Commoner
causes include zinc toxicity (through ingestion of toys, bolts or coins
containing high levels of zinc) [47] or iron overload. e latter is
usually iatrogenic through iron injections or repeat transfusions. Some
other common iatrogenic oxidants and toxins are listed in [Table 2],
with a more complete list is provided in Haematology texts eg [7].
Table 2. Some toxins and iatrogenic oxidants causing haemolytic anaemia in dogs and
Acetaminophen (paracetamol)
Acetylsalicylic acid (aspirin)
Allium spp.
Carprofen and other non-steroidal anti-inammatories
Iron overload
Methylene blue
Propylene glycol
Vitamin K and vitamin K antagonists
Red Cell Antioxidant Defence
Notwithstanding the potential oxidative peril and their limited
capacity for repair by protein synthesis, red cells must survive for
some one hundred and twenty days in the case of humans and dogs,
and about seventy days in the case of cats. Although the red cell is
well equipped with antioxidant defences, problems arise when
oxidative challenge exceeds the red cell antioxidant capacity. e
result is oxidative damage to membrane lipids and proteins, and to
haemoglobin itself. Oxidised haemoglobin, methaemoglobin (heme
Fe3+ instead of the normal Fe2+), is unable to carry oxygen and is
also liable to denaturation and precipitation as insoluble sulphHb
containing Heinz bodies, or to form eccentrocytes in which the
Hb is restricted to one side of the cell [13]. Other changes include
crosslinking of the cytoskeleton, thiol oxidation, depletion of reduced
glutathione and cation imbalance. e result is a fragile red cells with
impaired rheology liable to intravascular haemolysis with anaemia,
haemoglobinuria and poor oxygen-carrying capacity [48].
Antioxidant provision of red cells is provided by both enzymatic and
non-enzymatic pathways. Five enzymes are heavily involved: catalase
which reduces hydrogen peroxide to oxygen and water, glutathione
reductase uses NADH to reduce oxidised methaemoglobin, superoxide
dismutase scavenges superoxide anions generating hydrogen peroxide
and oxygen in the process, and glutathione peroxidase uses NADPH
to remove both red cell hydrogen peroxide and organic peroxides [49],
as does membrane-associated perioxiredoxin-2 which can be reduced
via reduced glutathione, vitamin C or thioredoxin. Activities of these
enzymes do vary between species [50–52]. Catalase activity in the
red cells of dierence species is very variable [50, 53, 54]. Expression
John S Gibson (2019) Oxidative stress and haemolytic anaemia in dogs and cats: a comparative approach
Integr J Vet Biosci, Volume 3(3): 4–5, 2019
in dog red cells occurs at about a tenth of the amount in humans
whilst its specic activity is around a third that of human catalase
[55]. As a result, overall catalase activity in dog red cells is a thirtieth
that in humans [53, 55]. Non-enzymatic defence includes reduced
glutathione, vitamin C and vitamin E. erapeutic antioxidants
include dosing with N-acetyl cysteine, vitamin C and E. None are
particularly eective for rapid protection [39]. ere is a need for
more ecacious compounds. ese must be eective in the short term
and protect red cells from further oxidative damage and haemolysis
without the requirement for prolonged metabolism. Some human
compounds are listed in [Table 3].
Table 3. Antioxidants used in chemoprophylaxis of sickle cell disease in humans.
Therapy Effect References
Acetyl-L-carnitine Protects red cells from peroxidative
damage and maintains normal shape at
lower oxygen tensions
N-Acetylcysteine Increases levels of reduced glutathione
and decreases haemolysis
(quercetin, rutin &
Show inhibitory effect on haemolysis
due to thiol group oxidation
Glutamine Increases NAD redox potential and
NADH levels
Hydroxyurea Reduces markers of oxidative stress,
decreases lipid peroxidation and
increases level of antioxidant enzymes
Iron chelators:
deferiprone &
Remove iron from the membrane of red
cells, decrease lipid peroxidation and
increase antioxidant capacity
α-lipoic acid Protects red cells from peroxyl radical
induced haemolysis, increases levels
of reduced glutathione and increased
antioxidant gene expression
Melatonin Increases levels of antioxidants and
reduces rate of haemolysis
Statins Protects against oxidative damage by
increasing nitric oxide metabolites and
C-reactive protein
Vitamin C and E Decreases production of reactive oxygen
species, increases levels of reduced
glutathione and reduces haemolysis
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... 14 Also like people, anemic dogs have erythrocytic oxidative stress for which ROS are implicated, thereby leading to hemolysis and early senescence. 8,9,[14][15][16] Detection of ROS is appealing because it would allow a direct measure of oxidative status; however, ROS are difficult to measure in tissue because of their short half-life and high reactivity. 17 Direct measurement of ROS in dogs is described, 5 with its concentration primarily determined with methods that estimate total ROS through the free radical-scavenging ability of the tissue being analyzed. ...
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Objective: To validate the use of a flow cytometric assay that uses 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) to measure reactive oxygen species in the erythrocytes of healthy dogs. Animals: 50 healthy adult dogs. Procedures: Erythrocytes were incubated with DCFH-DA or a vehicle control (dimethyl sulfoxide), then incubated with (stimulated) or without (unstimulated) hydrogen peroxide. The flow cytometric assay was evaluated for specificity with increasing concentrations of DCFH-DA and hydrogen peroxide, and a polynomial regression line was applied to determine optimal concentrations. For precision, samples were analyzed 5 consecutive times for determination of intra- and interassay variability. Stability of samples stored at 4°C for up to 48 hours after blood collection was determined with flow cytometric analysis. Coefficient of variation (CV) was considered acceptable at 20%. Baseline measurements were used to determine an expected range of median fluorescence intensity for unstimulated erythrocytes incubated with DCFH-DA. Results: Erythrocytes were successfully isolated, and stimulated samples demonstrated higher median fluorescence intensity, compared with unstimulated samples. The intra-assay CV was 11.9% and 8.9% and interassay CV was 11.9% and 9.1% for unstimulated and stimulated samples, respectively. Unstimulated samples were stable for up to 24 hours, whereas stimulated samples were stable for up to 48 hours. Conclusions and clinical relevance: Flow cytometry for the measurement of reactive oxygen species in the erythrocytes of healthy dogs by use of DCFH-DA had acceptable specificity, precision, and stability. Flow cytometry is a promising technique for evaluating intraerythrocytic oxidative stress for healthy dogs.
Background: Many potentially toxic substances are carried by the circulatory system and excreted through the kidneys; therefore, the haematological and renal systems are particularly at risk of damage by a variety of toxicants. Treating affected patients requires a combination of supportive care and specific therapy. Aim of the article: This article is the third in a series of four. It discusses specific toxicants that affect the haematological and renal systems and outlines principles for managing patients presenting with the consequences of intoxication.
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Background Oxidative stress contributes to the complex pathophysiology of sickle cell disease. Oral therapy with pharmaceutical-grade l-glutamine (USAN, glutamine) has been shown to increase the proportion of the reduced form of nicotinamide adenine dinucleotides in sickle cell erythrocytes, which probably reduces oxidative stress and could result in fewer episodes of sickle cell–related pain. Methods In a multicenter, randomized, placebo-controlled, double-blind, phase 3 trial, we tested the efficacy of pharmaceutical-grade l-glutamine (0.3 g per kilogram of body weight per dose) administered twice daily by mouth, as compared with placebo, in reducing the incidence of pain crises among patients with sickle cell anemia or sickle β⁰-thalassemia and a history of two or more pain crises during the previous year. Patients who were receiving hydroxyurea at a dose that had been stable for at least 3 months before screening continued that therapy through the 48-week treatment period. Results A total of 230 patients (age range, 5 to 58 years; 53.9% female) were randomly assigned, in a 2:1 ratio, to receive l-glutamine (152 patients) or placebo (78 patients). The patients in the l-glutamine group had significantly fewer pain crises than those in the placebo group (P=0.005), with a median of 3.0 in the l-glutamine group and 4.0 in the placebo group. Fewer hospitalizations occurred in the l-glutamine group than in the placebo group (P=0.005), with a median of 2.0 in the l-glutamine group and 3.0 in the placebo group. Two thirds of the patients in both trial groups received concomitant hydroxyurea. Low-grade nausea, noncardiac chest pain, fatigue, and musculoskeletal pain occurred more frequently in the l-glutamine group than in the placebo group. Conclusions Among children and adults with sickle cell anemia, the median number of pain crises over 48 weeks was lower among those who received oral therapy with l-glutamine, administered alone or with hydroxyurea, than among those who received placebo, with or without hydroxyurea. (Funded by Emmaus Medical; number, NCT01179217.)
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The purpose of this study was to investigate the therapeutic effect of hydrogen on the therapy of onion poisoned dogs. A total of 16 adult beagle dogs were divided into two groups (control and hydrogen) and all were fed dehydrated onion powder at the dose of 10 g/kg for three days. The dogs of the experimental group were given subcutaneous injection of 0.2 mL/kg of hydrogen for 12 days after making the poisoned model successful. Blood samples were collected before feeding onions, one day before injecting hydrogen, and 2 h after the injection of hydrogen on days 1, 3, 5, 7, 9, and 12. Control dogs were not treated with hydrogen. The levels of leukocyte production, anaemia, red blood cell degeneration which was reflected by the values of Heinz body count, haemolytic ratio, and oxidative products in hydrogen treated group were lower than in control dogs on some days. The capacity of medullary haematopoiesis that was based on reticulocyte counts, and the antioxidation in hydrogen group were higher compared with control group. However, the differences in renal function were not obvious in both groups. Accordingly, it was concluded that subcutaneous injection of hydrogen could alleviate the symptoms in onion poisoned dogs.
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Background The main function of hemoglobin (Hb) is to transport oxygen in the circulation. It is among the most highly studied proteins due to its roles in physiology and disease, and most of our understanding derives from comparative research. There is great diversity in Hb gene evolution in placental mammals, mostly in the repertoire and regulation of the β-globin subunits. Dogs are an ideal model in which to study Hb genes because: 1) they are members of Laurasiatheria, our closest relatives outside of Euarchontoglires (including primates, rodents and rabbits), 2) dog breeds are isolated populations with their own Hb-associated genetics and diseases, and 3) their high level of health care allows for development of biomedical investigation and translation. ResultsWe established that dogs have a complement of five α and five β-globin genes, all of which can be detected as spliced mRNA in adults. Strikingly, HBD, the allegedly-unnecessary adult β-globin protein in humans, is the primary adult β-globin in dogs and other carnivores; moreover, dogs have two active copies of the HBD gene. In contrast, the dominant adult β-globin of humans, HBB, has high sequence divergence and is expressed at markedly lower levels in dogs. We also showed that canine HBD and HBB genes are complex chimeras that resulted from multiple gene conversion events between them. Lastly, we showed that the strongest signal of evolutionary selection in a high-altitude breed, the Bernese Mountain Dog, lies in a haplotype block that spans the β-globin locus. Conclusions We report the first molecular genetic characterization of Hb genes in dogs. We found important distinctions between adult β-globin expression in carnivores compared to other members of Laurasiatheria. Our findings are also likely to raise new questions about the significance of human HBD. The comparative genomics of dog hemoglobin genes sets the stage for diverse research and translation.
Examination of the red blood cells (RBCs) of eight dogs with familial stomatocytosis-hypertrophic gastritis (FS-HG), a multiorgan disease associated with hemolytic anemia, hereditary stomatocytosis (HSt), and hypertrophic gastritis resembling Menetrier's disease in man, showed abnormal osmotic fragility, normal mean corpuscular volume, slightly increased cell water, and normal cation content and cation fluxes. Cholesterol was decreased in RBC and increased in plasma. In both RBCs and plasma, total phospholipid (PL) was normal, phosphatidylcholine (PC) decreased, and sphingomyelin increased. The palmitic acid content of PC was increased, and the stearic acid content of PC was decreased. Sodium dodecyl sulfate electrophoresis of RBC membrane proteins was normal. These findings have not been described previously in HSt. They suggest that in FS-HG, abnormal composition of the PL in RBCs secondary to abnormal PL in plasma causes defective membrane function and stomatocytic shape-change. This conclusion was supported by a shortened half-life of 51Cr-labeled RBCs from normal dogs after transfusion in dogs with FS-HG. It was concluded (1) that not all hereditary forms of stomatocytosis are necessarily associated with an intrinsic structural defect of the RBC membrane, but that the change in shape of RBC may also be induced by abnormal composition of the plasma; (2) that stomatocytosis may be caused by loss of membrane surface area rather than by the increased cation uptake such as has been shown in some human kindreds with HSt, (3) that FS-HG is a disorder of lipid metabolism, and by consequence, (4) that abnormal lipid metabolism might be involved in the pathogenesis of Menetrier's disease.
Sickle cell disease and thalassemia have distinctly different mutations, but both share common complications from a chronic vasculopathy. In the past, fetal hemoglobin–modulating drugs have been the main focus of new therapy, but the increased understanding of the complex pathophysiology of these diseases has led to the development of novel agents targeting multiple pathways that cause vascular injury. This review explores the pathophysiology of hemoglobinopathies and novel drugs that have reached phase 1 and 2 clinical trials. Therapies that alter cellular adhesion to endothelium, inflammation, nitric oxide dysregulation, oxidative injury, altered iron metabolism, and hematopoiesis will be highlighted. To evaluate these therapies optimally, recommendations for improving clinical trial design in hemoglobinopathies are discussed.
Key Points The reversible association of deoxyHb with band 3 acts as an O2-triggered molecular switch to regulate erythrocyte properties. Transgenic mice lacking the deoxyHb site on band 3 fail to respond to changes in O2 with changes in erythrocyte properties.
Recent clinical studies suggest that the beneficial effects of statins on cardiovascular risk may not only be due to their cholesterol lowering effects, but also to their cholesterol- independent - pleiotropic - effects. These effects include improvement of endothelial function, attenuating vascular and myocardial remodeling, inhibiting vascular inflammatory response, and stabilizing atherosclerotic plaques, mechanisms which are important in chronic process of atherogenesis, and are particularly pronounced in emerging acute cardiovascular events. This review presents statins pleiotropism through results of basic and clinical studies, with special emphasis on the importance of pleiotropic effects in patients with acute coronary syndrome and in high risk patients with stable coronary artery disease.
Hemolytic anemias involve the premature destruction of red blood cells. Although oxidative stress is not the primary etiology of most hemolytic anemias, it mediates several of their pathologies, including hemolysis. It is generated in red blood cells and other blood cells by several causes, most commonly by iron overload. This chapter describes the role of oxidative stress and the therapeutic potential of antioxidants in various hemolytic anemias. Emphasis will be given to results obtained by flow cytometry for measuring oxidative stress parameters, including labile iron, as well as the antioxidant activities in various peripheral blood cells. This methodology enables the evaluation of the patient's status with respect to oxidative stress as well as monitoring of the effect of treatment. © Springer-Verlag Berlin Heidelberg 2014. All rights are reserved.