Understanding D-Ribose and Mitochondrial Function.

Mitochondria are important organelles referred to as cellular powerhouses for their unique properties of cellular energy production. With many pathologic conditions and aging, mitochondrial function declines, and there is a reduction in the production of adenosine triphosphate. The energy carrying molecule generated by cellular respiration and by pentose phosphate pathway, an alternative pathway of glucose metabolism. D-ribose is a naturally occurring monosaccharide found in the cells and particularly in the mitochondria is essential in energy production. Without sufficient energy, cells cannot maintain integrity and function. Supplemental D-ribose has been shown to improve cellular processes when there is mitochondrial dysfunction. When individuals take supplemental D-ribose, it can bypass part of the pentose pathway to produce D-ribose-5-phosphate for the production of energy. In this article, we review how energy is produced by cellular respiration, the pentose pathway, and the use of supplemental D-ribose.

Study protocol, randomized controlled trial: reducing symptom burden in patients with heart failure with preserved ejection fraction using ubiquinol and/or D-ribose.

BACKGROUND: Heart failure (HF), the leading cause of morbidity and mortality in the US, affects 6.6 million adults with an estimated additional 3 million people by 2030. More than 50% of HF patients have heart failure with preserved left ventricular ejection fraction (HFpEF). These patients have impaired cardiac muscle relaxation and diastolic filling, which investigators have associated with cellular energetic impairment. Patients with HFpEF experience symptoms of: (1) fatigue; (2) shortness of breath; and (3) swelling (edema) of the lower extremities. However, current HF guidelines offer no effective treatment to address these underlying pathophysiologic mechanisms. Thus, we propose a biobehavioral symptom science study using ubiquinol and D-ribose (therapeutic interventions) to target mitochondrial bioenergetics to reduce the complex symptoms experienced by patients with HFpEF. METHODS: Using a randomized, double-blind, placebo-controlled design, the overall objective is to determine if administering ubiquinol and/or D-ribose to HFpEF patients for 12 weeks would decrease the severity of their complex symptoms and improve their cardiac function. The measures used to assess patients' perceptions of their health status and level of vigor (energy) will be the Kansas City Cardiomyopathy Questionnaire (KCCQ) and Vigor subscale of the Profile of Mood States. The 6-min walk test will be used to test exercise tolerance. Left ventricular diastolic function will be assessed using innovative advanced echocardiography software called speckle tracking. We will measure B-type natriuretic peptides (secreted from ventricles in HF) and lactate/ATP ratio (measure of cellular energetics). DISCUSSIONS: Ubiquinol (active form of Coenzyme Q10) and D-ribose are two potential treatments that can positively affect cellular energetic impairment, the major underlying mechanism of HFpEF. Ubiquinol, the reduced form of CoQ10, is more effective in adults over the age of 50. In patients with HFpEF, mitochondrial deficiency of ubiquinol results in decreased adenosine triphosphate (ATP) synthesis and reduced scavenging of reactive oxygen species. D-ribose is a substrate required for ATP synthesis and when administered has been shown to improve impaired myocardial bioenergetics. Therefore, if the biological underpinning of deficient mitochondrial ATP in HFpEF is not addressed, patients will suffer major symptoms including lack of energy, fatigue, exertional dyspnea, and exercise intolerance. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03133793 ; Data of Registration: April 28, 2017.

Ubiquinol treatment for TBI in male rats: Effects on mitochondrial integrity, injury severity, and neurometabolism.

Following traumatic brain injury (TBI), there is significant secondary damage to cerebral tissue from increased free radicals and impaired mitochondrial function. This imbalance between reactive oxygen species (ROS) production and the effectiveness of cellular antioxidant defenses is termed oxidative stress. Often there are insufficient antioxidants to scavenge ROS, leading to alterations in cerebral structure and function. Attenuating oxidative stress following a TBI by administering an antioxidant may decrease secondary brain injury, and currently many drugs and supplements are being investigated. We explored an over-the-counter supplement called ubiquinol (reduced form of coenzyme Q10), a potent antioxidant naturally produced in brain mitochondria. We administered intra-arterial ubiquinol to rats to determine if it would reduce mitochondrial damage, apoptosis, and severity of a contusive TBI. Adult male F344 rats were randomly assigned to one of three groups: (1) Saline-TBI, (2) ubiquinol 30 minutes before TBI (UB-PreTBI), or (3) ubiquinol 30 minutes after TBI (UB-PostTBI). We found when ubiquinol was administered before or after TBI, rats had an acute reduction in brain mitochondrial damage, apoptosis, and two serum biomarkers of TBI severity, glial fibrillary acidic protein (GFAP) and ubiquitin C-terminal hydrolase-L1 (UCH-L1). However, in vivo neurometabolic assessment with proton magnetic resonance spectroscopy did not show attenuated injury-induced changes. These findings are the first to show that ubiquinol preserves mitochondria and reduces cellular injury severity after TBI, and support further study of ubiquinol as a promising adjunct therapy for TBI.

Ubiquinol decreases hemorrhagic shock/resuscitation-induced microvascular inflammation in rat mesenteric microcirculation.

Hemorrhagic shock (HS) is a leading cause of death in traumatic injury. Ischemia and hypoxia in HS and fluid resuscitation (FR) creates a condition that facilitates excessive generation of reactive oxygen species (ROS). This is a major factor causing increased leukocyte-endothelial cell adhesive interactions and inflammation in the microcirculation resulting in reperfusion tissue injury. The aim of this study was to determine if ubiquinol (coenzyme Q10) decreases microvascular inflammation following HS and FR. Intravital microscopy was used to measure leukocyte-endothelial cell adhesive interactions in the rat mesentery following 1-h of HS and 2-h post FR with or without ubiquinol. Hemorrhagic shock was induced by removing ~ 40% of anesthetized Sprague Dawley rats' blood volume to maintain a mean arterial blood pressure <50 mmHg for 1 h. Ubiquinol (1 mg/100 g body weight) was infused intravascularly in the ubiquinol group immediately after 1-h HS. The FR protocol included replacement of the shed blood and Lactate Ringer's in both the control and ubiquinol groups. We found that leukocyte adherence (2.3 ± 2.0), mast cell degranulation (1.02 ± 0.01), and ROS levels (159 ± 35%) in the ubiquinol group were significantly reduced compared to the control group (10.8 ± 2.3, 1.36 ± 0.03, and 343 ± 47%, respectively). In addition, vascular permeability in the control group (0.54 ± 0.11) was significantly greater than the ubiquinol group (0.34 ± 0.04). In conclusion, ubiquinol attenuates HS and FR-induced microvascular inflammation. These results suggest that ubiquinol provides protection to mesenteric microcirculation through its antioxidant properties.

Effects of ubiquinol with fluid resuscitation following haemorrhagic shock on rat lungs, diaphragm, heart and kidneys.

Haemorrhagic shock (HS) and fluid resuscitation can lead to increased reactive oxygen species (ROS), contributing to ischaemia-reperfusion injury and organ damage. Ubiquinol is a potent antioxidant that decreases ROS. This study examined the effects of ubiquinol administered with fluid resuscitation following controlled HS. Adult male Sprague-Dawley rats were randomly assigned to treatment [ubiquinol, 1 mg (100 g body weight)(-1)] or control groups. Rats were subjected to 60 min of HS by removing 40% of the total blood volume to a mean arterial pressure ∼45-55 mmHg. The animals were resuscitated with blood and lactated Ringer solution, with or without ubiquinol, and monitored for 120 min. At the end of the experiments, the rats were killed and the lungs, diaphragm, heart and kidneys harvested. Leucocytes were analysed for mitochondrial superoxide at baseline, end of shock and 120 min following fluid resuscitation using MitoSOX Red. Diaphragms were examined for hydrogen peroxide using dihydrofluorescein diacetate and confocal microscopy. The apoptosis in lungs, diaphragm, heart and kidneys was measured using fluorescence microscopy with acridine orange and ethidium bromide. Leucocyte mitochondrial superoxide levels were significantly lower in rats that received ubiquinol than in the control animals. Production of hydrogen peroxide and apoptosis were significantly reduced in the organs of rats treated with ubiquinol. These findings suggest that ubiquinol, administered with fluid resuscitation after HS, attenuates ROS production and apoptosis. Thus, ubiquinol is a potent antioxidant that may be used as a potential treatment to reduce organ injury following haemorrhagic events.

Biomarkers: an important clinical assessment tool.

Helping clinicians to predict, diagnose, and monitor disease.

Coenzyme Q10--a therapeutic agent.

Coenzyme Q10 (CoQ10) is critical to production of adenosine triphosphate and is an antioxidant that scavenges reactive oxygen species during oxidative stress. The use of CoQ10 in treating oxidative stress in cardiovascular diseases, diabetes, and cancer is reviewed.

Effects of fluid resuscitation and dopamine on diaphragm performance, hydrogen peroxide, and apoptosis following hemorrhagic shock in a rat model.

The objective of this study was to determine the effectiveness of lactated Ringer's (LR) solution, sodium hydroxyethyl starch (hetastarch), and dopamine (DA) on diaphragm shortening (DS), diaphragm blood flow (DBF), diaphragm hydrogen peroxide (H2O2), and diaphragm apoptosis following hemorrhagic shock (HS). Sprague-Dawley rats were assigned to the following groups: HS, LR, LR plus DA, hetastarch, and hetastarch plus DA. After removing 40% of the blood volume, with exception of the HS group, an equal volume of resuscitation fluid was administered. The diaphragm was excised so that DBF, H2O2, and apoptosis could be measured. LR did not increase DBF and DS, whereas the other fluids increased DBF and DS. H2O2 and apoptosis decreased with LR administration. H2O2 and apoptosis were decreased to a much greater extent with LR plus DA, hetastarch, and hetastarch plus DA infusions. In conclusion, LR plus DA, hetastarch, and hetastarch plus DA maintained DS and DBF, which may be attributed to the decreases in reactive oxygen species as reflected by H2O2 and apoptosis.

Understanding the effects of oxygen administration in haemorrhagic shock.

AIMS AND OBJECTIVES: the aim of this article is to provide a review of the literature regarding oxygen administration and the use of oxygen in patients experiencing haemorrhagic shock (HS). RESULTS: oxygen is administered to patients to assist them in maintaining oxygenation. The administration of oxygen is complex and varies significantly among patients. In order to optimize patient care, clinicians need to be aware of the potential effects, both beneficial and harmful, that oxygen can have on the body. INCLUSION AND EXCLUSION CRITERIA: literature inclusion criteria for this article was any article (1995 to present) pertaining to oxygen administration and HS. Also included were articles related to tissue injury caused by an overabundance of free radicals with the administration of oxygen. Articles related to oxygen and wound healing, pollution, aerospace, food and industrial uses were excluded. CONCLUSIONS: this review of the literature provides an overview of the use of oxygen in clinical practice and HS. The harmful effects of oxygen are highlighted to alert the clinician to this potential when there is an overabundance of oxygen. RELEVANCE TO CLINICAL PRACTICE: oxygen is one of the most common drugs used in the medical community; however, the effects of oxygen on the body are not well understood. The use of oxygen if not prescribed correctly can cause cellular damage and death. Clinicians need to be more aware of the effects of oxygen and the damage it may cause if not administered properly.

Mitochondria: the hemi of the cell.

There are many organelles within a cell, each with individual responsibilities required for life. Of these organelles, the mitochondria are the hemi of the cell, producing the energy necessary for cell function. Reactive oxygen species can cause mitochondrial dysfunction and contribute to many diseases often seen in emergency departments. When reactive oxygen species are produced, the mitochondria undergo functional and structural changes causing the release of cytochrome c. Cytochrome c is responsible for activating apoptotic pathways leading to cell death. Apoptosis, or programmed cell death, is needed to maintain homeostasis in the body; however, when this occurs prematurely by an increase in reactive oxygen species production, many pathological conditions can occur. Clinicians in emergency departments caring for patients with different diseases should consider that the mitochondria may play an important role in patients' recovery. For instance, myocardial infarctions and burns are two examples of altered physiologic states that play a role in mitochondrial dysfunction. Awareness of the different treatments that target the mitochondria will prepare emergency department clinicians to better care for their patients.

Apoptotic-related protein expression in the diaphragm and the effect of dopamine during inspiratory resistance loading.

Dopamine (DA) is a free radical scavenger that attenuates apoptosis. We studied the effects of normal saline (NS) and DA on diaphragm apoptotic protein expression following 60 min of inspiratory resistance loading in rats. We tested for 27 apoptotic-related proteins and found 12 in the diaphragm. Of the 12 proteins, superoxide dismutase copper zinc (SOD [CuZn]) and proprioceptive event related potential (PERP) were significantly higher in the DA group than in the NS and sham groups (p = .002, p = .007). DA group diaphragms had significantly greater expression of SOD (CuZn) than the NS (p = .005) and sham group diaphragms (p = .003). Likewise, the DA group had significantly greater expression of PERP than the NS group (p = .008). These results suggest that DA decreases diaphragm apoptosis through elevated expression of SOD (CuZn). The identification of 12 apoptotic-related proteins will assist investigators as they study diaphragm apoptosis.

Dopamine alleviation of diaphragm contractile dysfunction and reduction of deoxyribonucleic acid damage in rats.

BACKGROUND: Weaning difficulties from mechanical ventilation are associated with diaphragm fatigue and reduced respiratory muscle endurance capacity. Often the work of breathing is increased during the weaning process as a result of inspiratory resistance loading (IRL). IRL produces increased free radical formation that contributes to deoxyribonucleic acid (DNA) damage. The purpose of this study was to determine whether dopamine reduced nuclei DNA damage when the work of breathing was increased. We hypothesized that the administration of low-dose dopamine (2 microg/kg/min) during IRL decreases myonuclei DNA damage associated with free radical formation. METHODS: In this in vivo study, 30 male Sprague-Dawley rats were divided into three groups: (1) the sham group receiving no IRL or no intravenous fluids, (2) IRL with administration intravenous saline, and (3) IRL with intravenous low-dose dopamine (2 microg/kg/min). All rats from the same breed and similar colonies were purchased from one laboratory facility to ensure homogeneity. The animals were anesthetized and tracheotomized, and an ultrasonic sensor was attached to the right hemidiaphragm to measure diaphragm shortening. Diaphragm fatigue was produced by IRL. Dopamine (2 microg/kg/min) was infused intravenously before and during loading. The diaphragms were excised, and myonuclei DNA damage was measured using the fluorescent dyes ethidium bromide and acridine orange and comet analyses as indices of free radical injury. RESULTS: In rats receiving saline, diaphragm shortening decreased by 37% after 45 minutes of IRL (P = .002) compared with baseline. In contrast, rats infused with dopamine exhibited a 31% increase in diaphragm shortening after 45 minutes of IRL (P = .037). With the use of differential dye uptake, in the saline group 59% of the nuclei were apoptotic, and 18% were necrotic. However, in the dopamine group there was significantly less apoptotic nuclei (16%, P < .001) and necrotic nuclei (7%, P = .005). Myonuclei DNA damage, measured by comet analyses, was associated with tail length and tail olive moment, which were 37% and 60% greater, respectively, in the saline group than in the dopamine group (P < .05). CONCLUSION: These data support the hypothesis that low-dose dopamine during IRL reduced myonuclei DNA damage as measured by the fluorescent dyes and comet analysis. In addition, diaphragm fatigue was prevented by the administration of dopamine during IRL.

Understanding proteomics.

The purpose of this article is to describe proteomics, to discuss the importance of proteomics, to review different methods for protein measurement, and to illustrate how knowledge of proteomics might improve patient care. Among common laboratory determinations are those involving enzymatic (protein) function. Although the presence or activity of proteins may be seen clinically as incidental, proteins represent the engines through which critical life processes ensue. A selected review of the literature is presented to define and explain proteomics and to review the various techniques to measure proteins. A case-study approach is used to illustrate how proteomics can be utilized for detecting and monitoring disease. The human genome has been completely sequenced and proteomics has emerged as a way to unravel the biochemical and physiological mechanisms of diseases at the functional level. This review includes the recent discoveries regarding proteomics and its importance in the detection and treatment of disease.

Detection of dopamine receptor subtypes in the rat diaphragm.

BACKGROUND: The administration of dopamine using an in vivo animal model has been shown to prevent and treat diaphragm fatigue. OBJECTIVE: With the knowledge that dopamine stimulates alpha- and beta-adrenergic and dopamine receptors, the purpose of this study was to investigate whether dopamine receptors are present in the diaphragm. In addition, if dopamine receptors were detected, we would identify the class and subtype of dopamine receptors. METHOD: Radioligand binding studies and reverse transcriptase polymerase chain reaction experiments were used. RESULTS: The receptor binding studies were unable to establish whether dopamine receptors were present in the diaphragm. However, highly sensitive reverse transcriptase polymerase chain reaction experiments demonstrated that D(1)-like receptors (D(1) and D(5) receptors) were detected in the diaphragm. CONCLUSIONS: This study is the first to report the class and specific subtype of dopamine receptors found in the diaphragm. By identifying dopamine receptors in the diaphragm, we have a better understanding of the mechanisms by which dopamine treats and prevents diaphragm fatigue.

The role of apoptosis in respiratory diseases.

PURPOSE: The purpose of this article is to define apoptosis and describe how this cellular pathway is relevant to the pathogenesis of different respiratory diseases. This will assist clinical nurse specialists in understanding how new drugs and therapies inhibit and stimulate apoptotic pathways. BACKGROUND: Clinical nurse specialists need to expand their knowledge concerning the role of apoptosis so that they can better expand their spheres of influence. The 4 stages of apoptosis are discussed, as well as the various apoptotic pathways involved with asthma, emphysema, and acute respiratory distress syndrome that promote and inhibit apoptosis in patients. CONCLUSION: It is crucial for clinical nurse specialists to know what apoptosis is and how it relates to different pathophysiologic states. The challenge facing clinical nurse specialists is how to be kept informed and current concerning molecular and cellular mechanisms that are important in the practice setting. Strategies needed to maintain expertise include acquiring new knowledge, developing new skills, and changing attitudes about molecular biology. Apoptosis must become a significant part of any health professionals' continuing educational program because it has been recognized as the pathway to most any disease. Clinical nurse specialists who understand apoptosis and its pathways can use this knowledge to aid in the prevention and treatment of respiratory diseases.

Effect of dopamine on rat diaphragm apoptosis and muscle performance.

The purpose of this study was to determine whether dopamine (DA) decreases diaphragm apoptosis and attenuates the decline in diaphragmatic contractile performance associated with repetitive isometric contraction using an in vitro diaphragm preparation. Strenuous diaphragm contractions produce free radicals and muscle apoptosis. Dopamine is a free radical scavenger and, at higher concentrations, increases muscle contractility by simulating beta2-adrenoreceptors. A total of 47 male Sprague-Dawley rats weighing 330-450 g were used in a prospective, randomized, controlled in vitro study. Following animal anaesthetization, diaphragms were excised, and muscle strips prepared and placed in a temperature-controlled isolated tissue bath containing Krebs-Ringer solution (KR) or KR plus 100 microm DA. The solutions were equilibrated with oxygen (O2) at 10, 21 or 95% and 5% carbon dioxide, with the balance being nitrogen. Diaphragm isometric twitch and subtetanic contractions were measured intermittently over 65 min. The diaphragms were then removed and, using a nuclear differential dye uptake method, the percentages of normal, apoptotic and necrotic nuclei were determined using fluorescent microscopy. There were significantly fewer apoptotic nuclei in the DA group diaphragms than in the KR-only group diaphragms in 10 and 21% O2 following either twitch or subtetanic contractions. Dopamine at 100 microm produced only modest increases in muscle performance in both 10 and 21% O2. The attenuation of apoptosis by DA was markedly greater than the effect of DA on muscle performance. Dopamine decreased diaphragmatic apoptosis, perhaps by preventing the activation of intricate apoptotic pathways, stimulating antiapoptotic mechanisms and/or scavenging free radicals.

Pressure-support ventilation and diaphragm shortening in the rat model.

Little is known about how pressure-support ventilation affects diaphragm performance because there is no direct measurement of diaphragm function in the clinical setting. An indicator of diaphragm performance or work is the product of diaphragm muscle shortening and intrathoracic pressure during inspiration. We studied the effect of pressure-support ventilation on diaphragm shortening, diaphragm work, and other cardiopulmonary parameters. In 15 anesthetized Sprague-Dawley male rats, pressure support was increased from 0 to 10 cm H2O in 2 cm increments. Increasing pressure support from 0 to 10 cm H2O resulted in respiratory rate decreasing 25%, tidal volume increasing 148%, minute ventilation increasing 91%, end-tidal carbon dioxide decreasing 5%, and cardiac output decreasing 30%. Progressively increasing pressure support to 10 cm H2O was accompanied by decreases in the end-inspiratory pressure without significant increases in diaphragm shortening. Therefore, diaphragm work was decreased. The lack of an increase in diaphragm shortening in the presence of an increase in tidal volume indicated that there was an augmentation of thoracic volume in the coronal and/or horizontal axes instead of the cephalocaudal axes throughout inspiration. These findings may be useful to nurse anesthetists in the understanding of diaphragm work when patients are being ventilated with pressure-support ventilation.

Apoptosis: understanding the new molecular pathway.

Advances in science have increased the knowledge of how cells die in the body (apoptosis). A basic understanding of this process can improve nurses' ability to review new scientific literature and enable them to provide safer bedside care.

The effect of dobutamine infusion on fractional diaphragm thickening and diaphragm blood flow during fatigue.

BACKGROUND: Diaphragm fatigue (DF) has been implicated in respiratory failure in diseases that increase inspiratory resistance loading (IRL) and may complicate weaning of patients from mechanical ventilation. OBJECTIVE: The purpose of this study was to examine the effects of dobutamine administration (10 micro g/kg/min) on DF and to identify the mechanisms by which dobutamine augments diaphragm shortening and diaphragm blood flow (DBF) during fatigue with a rat model. METHODS: The study had an experimental design with 3 groups of Sprague-Dawley rats (n = 38) with 4 experimental periods: period 1, control; period 2, application of IRL; period 3, treatment; and period 4, recovery. DF was produced via IRL. During period 3 treatment, normal saline solution was infused in group I, dobutamine in group II, and dobutamine plus butoxamine hydrochloride in group III. The percent change in fractional diaphragm thickness (FDT) during inspiration reflected diaphragm shortening. DBF and aortic blood flow were determined with fluorescent microspheres. Diaphragm vascular resistance and systemic vascular resistance were calculated on the basis of Poiseuille's equation. RESULTS: Results indicated infusion of dobutamine increased FDT (P =.01) and DBF (P =.009) with respect to fatigue levels. The effects of dobutamine on FDT and DBF were attenuated with infusion of butoxamine hydrochloride (a beta-2 adrenoceptor antagonist) with respect to fatigue. CONCLUSION: Administration of dobutamine at a rate similar to that used clinically increased diaphragm muscle contractility (FDT) and DBF in diaphragms fatigued by IRL. The dobutamine effect on FDT may be the result of restoration of the balance between diaphragm energy consumption and energy delivery to the diaphragm by increasing DBF. Butoxamine hydrochloride attenuated the dobutamine-induced increase in DBF, indicating dobutamine produced vasodilatation via beta-2 adrenoceptors. Thus, the administration of intravenous dobutamine may be a useful adjunct in the treatment of DF.

Understanding renal dose dopamine.

Low-dose dopamine is a widely administered drug used often in critical care settings to prevent or treat patients with low urinary output. There are new data to support that low-dose dopamine may have side effects and not always increase renal perfusion to the kidneys. This article is a review of the current use of low-dose dopamine, the role of dopamine in the kidneys, and the potential risks of infusing this drug to patients.