Michael J Simmonds

Michael J Simmonds
Griffith University · Biorheology Research Laboratory

Doctor of Philosophy

About

77
Publications
25,933
Reads
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1,287
Citations
Citations since 2016
55 Research Items
1029 Citations
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
2016201720182019202020212022050100150200
Introduction
Biophysical approaches to blood cells. Intracellular responses to mechanical stimuli in blood.
Additional affiliations
May 2013 - present
Griffith University
Position
  • Member
May 2011 - present
Bond University
Position
  • Interactions between exercise and hemorheology
April 2010 - May 2011
Bond University

Publications

Publications (77)
Article
Full-text available
BACKGROUND: Previous studies have demonstrated that red blood cells (RBC) either lyse or at least experience mechanical damage following prolonged exposure to high shear stress (≥100 Pa). Conversely, prolonged shear stress exposure within the physiological range (5–20 Pa, 300 s) was recently reported to improve RBC deformability. This study investi...
Article
Full-text available
Introduction: Despite current generation mechanical assist devices being designed to limit shear stresses and minimise damage to formed elements in blood, severe secondary complications suggestive of impaired rheological functioning are still observed. At present, the precise interactions between the magnitude-duration of shear stress exposure and...
Article
Full-text available
The present study was designed to investigate the oxidant susceptibility of red blood cells (RBC) from four species (echidna, human, koala, Tasmanian devil) based on changes in cellular deformability. These species were specifically chosen based on differences in lifestyle and/or biology associated with varied levels of oxidative stress. The major...
Article
Full-text available
The effect of exercise-induced lactate production on red blood cell deformability and other blood rheological changes is controversial, given heavy-exercise induces biochemical processes (e.g., oxidative stress) known to perturb haemorheology. The aim of the present study was to examine the haemorheological response to a short-duration cycling prot...
Article
Full-text available
Introduction: Given the severity of the current imbalance between blood donor supply and recipient demand, discarded blood drawn from the routine venesections of haemochromatosis (HFE-HH) patients may serve as a valuable alternative source for blood banks and transfusion. We investigated whether functional or biochemical differences existed betwee...
Article
Cell exclusion in spiral groove bearing (SGB) excludes red blood cells from high shear regions in the bearing gaps and potentially reduce haemolysis in rotary blood pumps. However, this mechanobiological phenomenon has been observed in ultra-low blood haematocrit only, whether it can mitigate blood damage in a clinically-relevant blood haematocrit...
Article
Full-text available
The purpose of this study was to assess how severe acute hypoxia alters the neural mechanisms of muscle activation across a wide range of torque output in a fatigued muscle. Torque and electromyography responses to transcranial and motor nerve stimulation were collected from 10 participants (27 yr ± 5 yr, 1 female) following repeated performance of...
Article
Full-text available
Investigating flowing red blood cell (RBC) morphology and orientation is important for elucidating physiology and disease; existing commercially available products are limited to observing cell populations or single cells. In this protocol, we create a custom apparatus that combines coaxial brightfield microscopy with laser diffractometry to inspec...
Article
Mature circulating red blood cells (RBC) are classically viewed as passive participants in circulatory function, given erythroblasts eject their organelles during maturation. Endogenous production of nitric oxide (NO) and its effects are of particular significance; however, the integration between RBC sensation of the local environment and subseque...
Article
Animal blood products are routinely used as surrogates for human tissue in haemocompatibility testing of rotary blood pumps. Bovine blood is particularly attractive due to the animal’s large blood volume; however, bovine red blood cells (RBC) differ substantially from those of human, both in biophysical properties and molecular composition. We aime...
Article
Full-text available
Plasma extraction from blood is essential for diagnosis of many diseases. The critical process of plasma extraction requires removal of blood cells from whole blood. Fluid viscoelasticity promotes cell migration towards the central axis of flow due to differences in normal stress and physical properties of cells. We investigated the effects of alte...
Article
Full-text available
The viscoelastic properties of red blood cells (RBC) facilitate flexible shape change in response to extrinsic forces. Their viscoelasticity is intrinsically linked to physical properties of the cytosol, cytoskeleton, and membrane—all of which are highly sensitive to supraphysiological shear exposure. Given the need to minimise blood trauma within...
Article
Full-text available
Despite decades of technological advancements in blood-contacting medical devices, complications related to shear flow-induced blood trauma are still frequently observed in clinic. Blood trauma includes haemolysis, platelet activation, and degradation of High Molecular Weight von Willebrand Factor (HMW vWF) multimers, all of which are dependent on...
Article
Acute hypoxia has been shown to impair voluntary activation of muscle and alter the excitability of the corticospinal motor pathway during exercise. However, little is known about how hypoxia alters the recovery of the motor system after performing fatiguing exercise. Here we assessed hypoxia‐related responses of motor pathways during both active c...
Article
Red blood cell (RBC) populations are inherently heterogeneous, given mature RBC lack the transcriptional machinery to re-synthesize proteins affected during in vivo aging. Clearance of older, less functional cells thus aids in maintaining consistent hemorheological properties. Scenarios occur, however, where portions of mechanically impaired RBC ar...
Article
In the lattice Boltzmann method (LBM), the relaxation time plays a significant role in the accuracy of simulation. However, there has been little attention directed toward evaluating the optimal relaxation time in literature. This paper proposes a systematic approach for the determination of the optimal relaxation time - particularly for very-low R...
Article
Simmonds, Michael J., Surendran Sabapathy, and Jean-Marc Hero. Rate-pressure product responses to static contractions performed at various altitudes. High Alt Med Biol. 00:000-000, 2021. Background: Adventure tourism has led to an unprecedented number of individuals being exposed to altitude, including those with subclinical cardiometabolic disord...
Article
Full-text available
Red blood cell (RBC) deformability is an essential component of microcirculatory function that appears to be enhanced by physiological shear stress, while being negatively affected by supraphysiological shears and/or free radical exposure. Given that blood contains RBCs with non-uniform physical properties, whether all cells equivalently tolerate m...
Article
Full-text available
Red blood cells (RBC) express a nitric oxide synthase isoform (RBC-NOS) that appears dependent on shear stress for Serine1177 phosphorylation. Whether this protein is equally activated by varied shears in the physiological range is less described. Here, we explored RBC-NOS Serine1177 phosphorylation in response to shear stress levels reflective of...
Article
Despite technological advances in ventricular assist devices (VADs) to treat end‐stage heart failure, hemocompatibility remains a constant concern, with supraphysiological shear stresses an unavoidable reality with clinical use. Given that impeller rotational speed is related to the instantaneous shear within the pump housing, it is plausible that...
Article
Blood is a non-Newtonian, shear-thinning fluid owing to the physical properties and behaviors of red blood cells (RBCs). Under increased shear flow, pre-existing clusters of cells disaggregate, orientate with flow, and deform. These essential processes enhance fluidity of blood, although accumulating evidence suggests that sublethal blood trauma—in...
Article
Background: Hemochromatosis (HH) is characterized by chronic iron accumulation, leading to deleterious effects to various organ systems. A common approach to managing iron load involves large-volume venesection. Some countries authorize HH venesections to be used in the development of transfusable blood products, although concerns remain regarding...
Article
Background: Individuals with hereditary hemochromatosis (HH) receive frequent blood withdrawals (ie, venesections) as part of their primary treatment to assist in normalizing blood iron levels. It remains unclear whether this source of blood is suitable for use in blood product development, as current data indicate that red blood cell (RBC) deform...
Article
New findings: What is the central question of this study? How does acute hypoxia alter central and peripheral fatigue during brief and sustained maximal voluntary muscle contractions? What is the main finding and its importance? Perception of fatigue during muscle contractions was progressively increased for 2 hr after hypoxic exposure. However, a...
Article
It was classically thought that the function of mammalian red blood cells (RBC) was limited to serving as a vehicle for oxygen, given the cell's abundance of cytosolic haemoglobin. Over the past decades, however, accumulating evidence indicates that RBC have the capacity to sense low oxygen tensions in hypoxic tissues, and subsequently release sign...
Article
Blood exposure to supraphysiological shear stress within mechanical circulatory support is suspected of reducing red blood cell (RBC) deformability and being primal in the pathogenesis of several secondary complications. No prior works have explored RBC dynamics with the resolution required to determine shear elastic modulus, and/or cell capillary...
Article
Full-text available
Nonsurgical bleeding is the most frequent complication of left ventricular assist device (LVAD) support. Supraphysiologic shear rates generated in LVAD causes impaired platelet aggregation, which increases the risk of bleeding. The effect of shear rate on the formation size of platelet aggregates has never been reported experimentally, although pla...
Article
Red blood cells (RBC) are constantly exposed to varying mechanical forces while traversing the cardiovascular system. Upon exposure to mechanical stimuli (e.g., shear stress), calcium enters the cell and prompts potassium-efflux. Efflux of potassium is accompanied by a loss of intracellular fluid; thus, the volume of RBC decreases proportionately (...
Article
The classic view of the red blood cell (RBC) presents a biologically inert cell, that upon maturation, has limited capacity to alter its physical properties. This view developed largely due to the absence of translational machinery and inability to synthesise or repair proteins in circulating RBC. Recent developments have challenged this perspectiv...
Article
Full-text available
Mechanical circulatory support device (MCS) design has improved over the years and yet blood damage (e.g., hemolysis) remains a problem. Accumulating evidence indicates a subhemolytic threshold for red blood cells (RBC)-a threshold at which RBC deformability is impaired prior to hemolysis. The current study aimed to assess the deformability of RBC...
Article
New findings: • What is the central question of this study? Quantitative values of shear rate-specific blood viscosity and shear stress in the human macrovasculature in response to exercise hyperaemia are unknown. • What is the main finding and its importance? Using the handgrip exercise model, we show that an increase in brachial artery shear rat...
Conference Paper
Purpose of study: clinical outcomes from Left Ventricular Assist Devices (LVADs) have improved significantly in recent decades. Common complications of long-term LVAD use include bleeding events, plausibly due to the supraphysiological shear environment of these pumps. Greater understanding of the impact of shear rate on the formation size of plate...
Article
This study aimed to quantify how acute hypoxia impacts firing characteristics of biceps brachii motor units (MUs) during sustained isometric elbow flexions. MU data were extracted from surface electromyography (EMG) during 25% maximal voluntary contractions (MVC) in 10 healthy subjects (age 22 ± 1 yr). Blood oxygen saturation (SpO2) was then stabil...
Article
Background: We sought to determine if women (65–74 y) can self-select an exercise intensity during walking commensurate with current physical activity recommendations. Methods: Thirteen healthy older women (age = 68 ± 3 y, body mass index = 25.7 ± 4.9 kg·m−2, peak O2 uptake = 24.1 ± 4.5 mL·kg−1·min−1) performed 4 30-min walking trials (2 × treadmil...
Article
Full-text available
The cellular deformability of red blood cells (RBC) is exceptional among mammalian cells and facilitates nutrient delivery throughout the microcirculation; however, this physical property is negatively impacted by oxidative stress. It remains unresolved whether the molecular determinants of cellular deformability – which in the contemporary model o...
Article
BACKGROUND: Red blood cells (RBC) are exposed to varying shear stress while traversing the circulatory system; this shear initiates RBC-derived nitric oxide (NO) production. OBJECTIVE: The current study investigated the effect of varying shear stress dose on RBC-derived NO production. METHODS: Separated RBC were prepared with the molecular probe,...
Article
Full-text available
With accumulating evidence that exercise capacity decreases all-cause mortality independent of adiposity, benefits may be gained by developing cardiorespiratory fitness measures that are specifically and sensitively designed for use with pediatric populations when cardiorespiratory fitness may be a contributing factor for obesity. This study aimed...
Article
Background Sickle cell disease (SCD) is a genetically inherited hemoglobinopathy in which deoxygenated hemoglobin S polymerizes, leading to stiff red blood cells (RBCs) and inefficient microcirculatory blood flow. Transfusion therapy acts as primary and secondary prevention of ischemic stroke in SCD. Whether blood transfusion alters the mechanical...
Poster
Background: Although individuals with haemochromatosis (HH), a disease characterised by an accumulation of iron above bodily needs, are able to donate blood in numerous countries, the discussion of whether the obtained blood is viable for use in transfusion remains unresolved. Given that red blood cells (RBC) from HH patients are rheologically diff...
Article
Introduction: Accumulating evidence demonstrates that subhaemolytic mechanical stresses, typical of circulatory support, induce physical and biochemical changes to red blood cells. It remains unclear, however, whether cell age affects susceptibility to these mechanical forces. This study thus examined the sensitivity of density-fractionated red bl...
Poster
Background: Physical properties of red blood cells (RBC), including cell aggregation and deformability, are significantly impaired in individuals with hemochromatosis (HH). Although many of the complications associated with HH (e.g., endothelial dysfunction) may be attributed to impaired blood rheology, it remains unknown whether common therapies h...
Article
Although rotary blood pumps (RBPs) sustain life, blood exposure to continuous supra‐physiological shear stress induces adverse effects (e.g., thromboembolism); thus, pulsatile flow in RBPs represents a potential solution. The present study introduced pulsatile flow to the HeartWare HVAD using a custom‐built controller and compared hemocompatibility...
Article
Circulation of blood depends, in part, on the ability of red blood cells (RBCs) to aggregate, disaggregate, and deform. The primary intrinsic disaggregating force of RBCs is derived from their electronegativity, which is largely determined by sialylated glycoproteins on the plasma membrane. Given supraphysiological shear exposure - even at levels b...
Article
Full-text available
Haemochromatosis remains the most prevalent genetic disorder of Caucasian populations in Australia and the United States, occurring in ∼1 of 200 individuals and having a carrier frequency of 10-14%. Hereditary haemochromatosis is an autosomal recessive condition, that is phenotypically characterised by a gradual accumulation of iron, above and beyo...
Article
Full-text available
Background: Red blood cell (RBC) deformability may increase, or decrease, following application of shear stress ("shear conditioning"), depending upon the specific magnitude and duration of exposure. However, the time course of altered RBC deformability following shear remains unresolved. Objective: We utilised shear conditioning known to increa...
Chapter
Management of organ failure has improved in recent years in parallel with advancements in interventions, including organ transplant, although the shortage of donor organs remains the rate-limiting step. The advent of mechanical alternatives to biological organs is a burgeoning area available to clinicians in a variety of scenarios, including short-...
Article
Patients receiving mechanical circulatory support often present with heightened inflammation and free radical production associated with pre-existing conditions in addition to that which is due to blood interactions with nonbiological surfaces. The aim of this experimental laboratory study was to assess the deformability of red blood cells (RBC) pr...
Article
Rotary blood pumps (RBPs) are used for mechanical circulatory support in heart failure patients but exhibit a reduced response to preload changes, which can lead to ventricular suction events. A passive control system, in the form of a compliant inflow cannula (IC), has been developed to mitigate suction, although this device may cause significant...
Article
The supra-physiological shear stress that blood is exposed to while traversing mechanical circulatory assist devices affects the physical properties of red blood cells (RBCs), impairs RBC deformability, and may induce hemolysis. Previous studies exploring RBC damage following exposure to supra-physiological shear stress have employed durations exce...
Article
Full-text available
Background: Current generation mechanical circulatory assist devices are designed to minimize high shears to blood for prolonged durations to avoid hemolysis. However, red blood cells (RBC) demonstrate impaired capacity to deform when exposed to shear stress (SS) well below the "hemolytic threshold". Objective: We endeavored to identify how chan...
Article
Purpose: It is unclear whether the respiratory compensation point (RCP) may be used as a valid surrogate for critical power (CP). Accordingly, we sought to determine the measurement agreement between CP and the RCP obtained during incremental cycling of varying ramp slopes. Methods: Eleven recreationally-active men completed three separate ramp-...
Article
Full-text available
Classic features of polycystic ovary syndrome (PCOS) include derangement of metabolic and cardiovascular health, and vascular dysfunction is commonly reported. These comor-bidities indicate impaired blood flow; however, other than limited reports of increased plasma viscosity, surprisingly little is known regarding the physical properties of blood...
Article
The aim of this study was to investigate how maximal intermittent contractions for a hand muscle influence cortical and reflex activity, as well as the ability to voluntarily activate, the homologous muscle in the opposite limb. Twelve healthy subjects (age: 24 ± 3 years, all right hand dominant) performed maximal contractions of the dominant limb...
Article
Background: The purpose of the present study was to investigate the effects of regular treadmill walking on plasma factors that increase low-shear blood viscosity and red blood cell aggregation in older women with type 2 diabetes. Methods: Eighteen women with type 2 diabetes (age: 69±3 yr; body mass index: 30.5±5.0 kg⋅m-2) performed 12-wk of 120...
Article
Endurance exercise can cause immunosuppression and increase the risk of upper respiratory illness. The present study examined changes in the secretion of T helper (Th) cell cytokines after endurance exercise. Ten highly trained road cyclists [mean±SEM: age 24.2±1.7 years; height 1.82±0.02 m; body mass 73.8±2.0 kg; peak oxygen uptake 65.9±2.3 mL/(kg...
Article
Full-text available
Since the identification of the elusive endothelium-derived relaxing factor as nitric oxide (NO), much attention has been devoted to understanding its physiological effects. NO is a free radical with many roles, and owing to its neutral charge and high diffusion capacity, it appears NO is involved in every mammalian biological system. Most attentio...
Article
Full-text available
Although markers of myocyte injury, electrolyte disturbances and an autonomic imbalance have been reported following exercise, the effect of prolonged strenuous activity on cardiac electrical conduction is not well understood. This study examined atrial and ventricular conduction dynamics during recovery from exercise. Electrocardiographic interval...
Article
Full-text available
The flow properties of blood play significant roles in tissue perfusion by contributing to hydrodynamic resistance in blood vessels. These properties are influenced by pathophysiological processes, thereby increasing the clinical relevance of blood rheology information. There is well-established clinical evidence for impaired blood fluidity in huma...
Article
Full-text available
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0071219 Background: The effect of exercise-induced lactate production on red blood cell deformability and other blood rheological changes is controversial, given heavy-exercise induces biochemical processes (e.g., oxidative stress) known to perturb haemorheology. The aim of the pres...
Article
Full-text available
The present review focuses on the past and recent knowledge in the field of exercise hemorheology and presents some unresolved issues for opening discussion. Acute exercise is associated with a rise in hematocrit which results in an increase in blood viscosity. Whereas increased blood viscosity was previously viewed as having negative consequences...
Article
Full-text available
We tested the effects of submaximal exercise on blood viscosity (η(b)), nitric oxide production (NO) and hemodynamics. Relationships between the exercise-induced changes that occurred in these parameters were investigated. Nine subjects performed exercise for 15 min at 105% of the first ventilatory threshold. Mean arterial pressure (MAP) and cardia...
Article
Full-text available
Heart rate variability (HRV) and haemorheology adaptations to 12 wk of varied-dose treadmill walking were investigated in women aged 65-74 yr with type 2 diabetes. Subjects were randomly allocated into two groups where exercise frequency and session duration were manipulated (Group 1: 2 × 60 min·wk(-1) or Group 2: 4 × 30 min·wk(-1)), but intensity...
Article
Full-text available
The extent of red blood cell (RBC) aggregation has widely been accepted as a reliable indicator of inflammatory processes. The ability to measure RBC aggregation indexes in capillary blood samples may simplify the application of the test and may bring advantages in its clinical usage as well as application in field studies. This study compared RBC...
Article
Full-text available
The blood of two Australian marsupials, the eastern grey kangaroo (Macropus giganteus) and the Tasmanian devil (Sarcophilus harrisii), has been reported to have greater oxygen-carrying capacity (i.e. haemoglobin content) when compared with that of placental mammals. We investigated whether alterations of blood rheological properties are associated...
Article
Full-text available
There is accumulating evidence that exercise may improve disturbed haemorheological parameters that are typically observed in various chronic diseases, thus there is a growing interest in exploring the influence of various exercise models for the improvement of haemorheology. Blood sampling using venipuncture, however, can be limiting during exerci...
Article
Full-text available
The principal determinants of oxygen uptake (VO2) kinetics are controversial, with dynamic changes in central and peripheral factors mediating oxygen supply and utilisation suggested to be limiting. The aim of this study was to determine whether important parameters of blood rheology were related to the exercise-induced time-course changes in VO2 a...
Article
The 'open window' theory is characterised by short term suppression of the immune system following an acute bout of endurance exercise. This window of opportunity may allow for an increase in susceptibility to upper respiratory illness (URI). Many studies have indicated a decrease in immune function in response to exercise. However many studies do...
Article
Full-text available
The purpose of this study was to determine if improved supramaximal exercise performance in trained cyclists following caffeine ingestion was associated with enhanced O(2) uptake (VO2 kinetics), increased anaerobic energy provision (accumulated O(2)-AO(2)-deficit), or a reduction in the accumulation of metabolites (for example, K(+)) associated wit...