A Brief Review of Three Common Supplements Used in Alzheimer's Disease.

Individuals with Alzheimer's disease (AD) and their caregivers are using supplements in an effort to halt the progression of the disease. Individuals at risk for or fearing Alzheimer's may use these supplements to try to prevent the disease. Senior care pharmacists are accessible and uniquely qualified to answer questions, make recommendations, and attempt to make drug therapy safe and effective for these individuals. With this in mind, it is important to know the data supporting (or not supporting) common supplements marketed toward those with AD. A review of efficacy and safety data, drug interactions, as well as the mechanism of action believed to benefit those with AD of three common supplements (Prevagen, Cerefolin NAC, and the omega-3 polyunsaturated fatty acid DHA), are highlighted.

Effects of a Supplement Containing Apoaequorin on Verbal Learning in Older Adults in the Community.

CONTEXT: The changes in verbal learning and working memory that often occur with aging may result in reduced social and intellectual interactions. These changes significantly affect an individual's quality of life. As humans age, the body's ability to regulate and maintain calcium levels is diminished. Pharmacological manipulation of the entry of free calcium (Ca2+) has been shown to be effective in increasing some aspects of cognitive function in the aged brain. Apoaequorin has been shown in laboratory studies to regulate levels of intracellular calcium in neuronal cells and to provide protection against ischemic cell death. OBJECTIVE: The study was designed to assess the effects of a supplement of apoaequorin on verbal learning and working memory. DESIGN: The current study, the Madison Memory Study, was a randomized, double-blind, placebo-controlled trial. SETTING: The study occurred in Madison, WI, USA. PARTICIPANTS: Participants were 218 community-dwelling adults, aged 40-91 y, with self-reported memory concerns. INTERVENTION: Participants were randomly assigned to receive either apoaequorin (apoaequorin group) or a matched placebo (control group) for 90 d. OUTCOME MEASURES: The study used quantitative, computerized tools for cognitive assessment the CogState International Shopping List (ISL) and the CogState ISL-Delayed Recall (ISL-DR). Scores from computerized cognitive tasks were measured at baseline and at several points during the 90-d study. RESULTS: No significant differences existed between the intervention and control groups in any parameter at baseline. The intervention group (apoaequorin group) showed a statistically significant improvement in verbal learning and recall on the ISL and the ISL-DR, respectively, during the 90-d study. Apoaequorin was tolerated very well in the study. CONCLUSIONS: The results indicated a strong relationship between apoaequorin and improvements on a quantitative measure of cognitive function, specifically verbal learning. The study found that apoaequorin is a well-tolerated supplement that improved cognitive function in aging adults. The results suggest potential utility for apoaequorin in addressing the declines in cognitive function associated with aging.

Safety assessment of the calcium-binding protein, apoaequorin, expressed by Escherichia coli.

Calcium-binding proteins are ubiquitous modulators of cellular activity and function. Cells possess numerous calcium-binding proteins that regulate calcium concentration in the cytosol by buffering excess free calcium ion. Disturbances in intracellular calcium homeostasis are at the heart of many age-related conditions making these proteins targets for therapeutic intervention. A calcium-binding protein, apoaequorin, has shown potential utility in a broad spectrum of applications for human health and well-being. Large-scale recombinant production of the protein has been successful; enabling further research and development and commercialization efforts. Previous work reported a 90-day subchronic toxicity test that demonstrated this protein has no toxicity by oral exposure in Sprague-Dawley rodents. The current study assesses the allergenic potential of the purified protein using bioinformatic analysis and simulated gastric digestion. The results from the bioinformatics searches with the apoaequorin sequence show the protein is not a known allergen and not likely to cross-react with known allergens. Apoaequorin is easily digested by pepsin, a characteristic commonly exhibited by many non-allergenic dietary proteins. From these data, there is no added concern of safety due to unusual stability of the protein by ingestion.

Microinjecting holo-aequorin into dechorionated and intact zebrafish embryos.

The injection of holo-aequorin into embryos at the one-cell stage, along with the use of a simple photomultiplier tube or luminescence imaging system, allows transient localized elevations of free cytosolic Ca(2+) to be recorded and observed during the first 24 h of zebrafish development. The technique for loading dechorionated or intact one-cell stage zebrafish embryos with holo-aequorin is described here.

Safety assessment of Apoaequorin, a protein preparation: subchronic toxicity study in rats.

Apoaequorin, a calcium-binding protein originally isolated from jellyfish is available commercially as a dietary supplement. The objective of the present study was to investigate potential adverse effects, if any, of Apoaequorin, a recombinant protein preparation, in rats following subchronic administration. For this study, Sprague-Dawley (Hsd:SD) rats (10/sex/group) were administered via oral gavage 0 (control), 92.6, 462.9, and 926.0mg/kg body weight (bw)/day of Apoaequorin preparation, for 90 days. The corresponding amount of Apoaequorin protein was 0, 66.7, 333.3 and 666.7 mg/kg bw/day, respectively. Administration of the Apoaequorin preparation did not result in any mortality. There were no clinical or ophthalmological signs, body weight, body weight gain, food consumption, food efficiency, clinical pathology or histopathological changes attributable to administration of Apoaequorin. Any changes noted were incidental and in agreement with those historically observed in the age and strain of rats used in this study. Based on the results of this study, the No Observed-Adverse-Effect Level (NOAEL) for Apoaequorin was determined as 666.7 mg/kg bw/day, the highest dose tested.

Characterization of intracellular Ca2+ transient by the hybrid logistic function in aequorin-injected rabbit and mouse papillary muscles.

Myocardial intracellular calcium (Ca2+) transients (CaTs) regulate tension generation and relaxation. Isometric tension curves are often analyzed using exponential equations; however, we previously demonstrated that hybrid logistic (HL) functions, which describe the difference between two S-shaped logistic functions, provide more accurate representations. In the present study, we investigated the potential application of HL functions for analyzing CaTs directly. CaTs were measured using the calcium-sensitive bioluminescent protein, aequorin, in 7 isolated rabbit right ventricular and 15 isolated mouse left ventricular papillary muscles. CaT data were fit by the least-squares method using HL and polynomial exponential (PE) function equations. The mean correlation coefficient (r) values of HL and PE fits were 0.9934 vs. 0.9523 in rabbit and 0.9980 vs. 0.9407 in mouse, respectively. The Z transformation of r value and the adjusted coefficient of determination (r squares) were higher, and the residual mean squares and Akaike information criterion values, which estimate goodness of fit between functions with different numbers of parameters, were lower for the HL curves than for the PE curves in both rabbit and mouse. There were significant correlations between the calculated values from the best-fit HL function curve and the primary CaT data. Thus the HL function curves more accurately described the amplitudes and time courses of CaTs in both rabbit and mouse papillary muscles. We speculate that the first logistic component curve reflects the concentration and time course of Ca2+ inflow into the cytoplasmic space, and that the second logistic component curve reflects the concentrations and time courses of Ca2+ removal from the cytoplasmic space as well as Ca2+ binding to troponin. This approach might provide a more robust model for studying CaTs and cardiac cycle regulation.

Mibefradil improves beta-adrenergic responsiveness and intracellular Ca(2+) handling in hypertrophied rat myocardium.

The present study investigated the effects of mibefradil, a novel T-type channel blocker, on ventricular function and intracellular Ca(2+) handling in normal and hypertrophied rat myocardium. Ca(2+) transient was measured with the bioluminescent protein, aequorin. Mibefradil (2 microM) produced nonsignificant changes in isometric contraction and peak systolic intracellular Ca(2+) concentration ([Ca(2+)](i)) in normal rat myocardium. Hypertrophied papillary muscles isolated from aortic-banded rats 10 weeks after operation demonstrated a prolonged duration of isometric contraction, as well as decreased amplitudes of developed tension and peak Ca(2+) transient compared with the sham-operated group. Additionally, diastolic [Ca(2+)](i) increased in hypertrophied rat myocardium. The positive inotropic effect of isoproterenol stimulation was blunted in hypertrophied muscles despite a large increase in Ca(2+) transient amplitude. Afterglimmers and corresponding aftercontractions were provoked with isoproterenol (10(-5) and 10(-4) M) stimulation in 4 out of 16 hypertrophied muscles, but were eliminated in the presence of mibefradil (2 microM). In addition, hypertrophied muscles in the presence of mibefradil had a significant improvement of contractile response to isoproterenol stimulation and a reduced diastolic [Ca(2+)](I), although a mild decrease of peak Ca(2+)-transient was also shown. However, verapamil (2 microM) did not restore the inotropic and Ca(2+) modulating effects of isoproterenol in hypertrophied myocardium. Mibefradil partly restores the positive inotropic response to beta-adrenergic stimulation in hypertrophied myocardium from aortic-banded rats, an effect that might be useful in hypertrophied myocardium with impaired [Ca(2+)](i) homeostasis.

Mechanisms underlying spontaneous calcium spiking in aequorin-loaded ROS 17/2.8 cells.

In earlier studies, McLeod and coworkers reported the detection of spontaneous calcium spiking in ROS 17/2.8 cells which they suggested was derived from individual cells progressing through mitosis or the cell cycle. They also indicated that the degree of spiking could be modulated by exposure of the cells to time-varying extremely low frequency electric fields. Given the implications of such observations for our understanding of the effects of electromagnetic fields on biological systems, it appeared important for mechanistic reasons to understand the basis of this spiking. In this study, we were able to confirm that spontaneous calcium spiking activity could be detected in ROS 17/2.8 cells and that this appeared to emanate from individual cells. We found this spiking to be completely dependent on extracellular calcium ions and to be independent of the inositol 1,4,5-trisphosphate-sensitive intracellular calcium store. This spiking is not reduced by treatments which slow down or block the passage of cells through the cell cycle. Further, we found that spiking was only detectable in the most highly aequorin-loaded subpopulation of cells whose growth rate is reduced and whose morphological appearance is abnormal. In conjunction with what is known about calcium spiking in other, nonexcitable mammalian cells in culture, the data presented strongly argue that the spontaneous calcium spiking observed in ROS 17/2.8 cells is unrelated to normal events of the cell cycle and most likely result from the damaging effects of excessive loading with aequorin.

The effects of theophylline on aequorin light transients and force in the isolated dog right ventricular myocardium.

Experiments were carried out to investigate the changes in intracellular Ca2+ transients associated with biphasic contractions that were elicited during interaction of theophylline with isoproterenol in the dog ventricular myocardium. For this purpose, effects of theophylline and isoproterenol on aequorin light transients and isometric contractions were assessed in the isolated canine ventricular trabeculae, superficial cells of which had been microinjected with the Ca2+ sensitive bioluminescent protein aequorin. The positive inotropic effect of theophylline (0.1-0.3 mM) was consistently associated with an increase in the amplitude of aequorin light transients. Theophylline at concentrations of 0.6 mM and higher decreased the amplitude of aequorin light transients, but the force of contraction increased further in association with a prominent prolongation of time to peak force. Theophylline (0.3 mM) enhanced the forskolin-induced increase in aequorin light transients and force. Theophylline (2 mM) inhibited the isoproterenol-induced increase in aequorin light transients associated with early phase of contraction in a reversible manner. A late phase of aequorin light transients was induced in association with late phase of contraction in the presence of both isoproterenol and theophylline. Thus, both the early and late phase of contraction were accompanied by corresponding phases of aequorin light transients. The relation between the amplitude of force and Ca2+ transients was markedly different and the late phase of contraction was associated with much lower aequorin light transients. The late phase of aequorin light transients induced by theophylline at a high concentration (10 mM) was enhanced by isoproterenol. These results indicate that theophylline (0.1-0.3 mM) increases the amplitude of Ca2+ transients through an accumulation of cyclic AMP by inhibition of the cyclic AMP phosphodiesterase activity. In concentrations of 0.6 mM and higher theophylline decreases the amplitude of the early phase aequorin light transients probably by inhibition of release of Ca2+ from the sarcoplasmic reticulum and induces simultaneously the late phase of contraction that may be associated with an increase in responsiveness to Ca2+ of myofibrils.

A chemical method for intracellular loading of the calcium indicator aequorin in mammalian skeletal muscle.

The bioluminescent calcium indicator aequorin was loaded into bundles of skeletal muscle fibers from the rat extensor digitorum longus by macroinjection, a technique previously applied only to cardiac muscle. After loading, the amplitude and time course of the twitch returned to control values, indicating lack of damage to the fibers. Individual light signals (i.e., calcium transients) were recorded during each twitch or tetanus without the need for signal averaging. The calcium transients obtained were qualitatively and quantitatively similar to those reported previously with microinjection of aequorin. Our data suggest that macroinjection may be the method of choice for loading aequorin into mammalian skeletal muscle.

Measurement of ionized cytoplasmic calcium mobilization with the photoprotein aequorin in human polymorphonuclear leukocytes activated by platelet activating factor (PAF).

The use of the sensitive photoprotein aequorin as a Ca2+ indicator in human polymorphonuclear leukocytes (PMN) not pretreated with cytochalasin B and stimulated with platelet activating factor (PAF) may help cast more light on the relative importance of intracellular and extracellular Ca2+ in PMN function. PAF elicits Ca2+ mobilization in PMN (resuspended in the presence of 1 mM extracellular Ca2+), in a concentration-dependent manner. The Ca2+ chelator ethyleneglycoltetraacetic acid (EGTA) abolishes Ca2+ mobilization, suggesting that almost all Ca2+ mobilized by PAF derives from the external medium. Aggregation and enzymatic release parallel the Ca2+ mobilization triggered by PAF. In contrast PAF appears to be only a weak stimulus of superoxide anion production (compared to the phorbol ester phorbol 12-myristate 13-acetate (PMA] and leukotriene B4 (LTB4) synthesis (compared to the Ca2+ ionophore A23187). The fact that PAF elicits Ca2+ mobilization, aggregation, secretion and LTB4 generation in human PMN supports the role of this phospholipid as a powerful mediator of physiopathological events involving PMN activation.

Coelenterate photoproteins as indicators of cytoplasmic free Ca2+ in small cells.

The Ca2+-activated photoproteins aequorin and obelin are capable of detecting rapid changes in free Ca2+ over the range 10nM-100uM. Whilst they have been used to quantify free Ca transients in giant cells for some time, their use in small mammalian cells has been restricted because of the difficulty of incorporating them into live cells without impairment of cell function. We have developed three methods for incorporating photoproteins into small cells (a) reversible cell swelling (b) membrane fusion and (c) intracellular release from pinocytotic vesicles. Formation of the membrane attack complex of complement (C5b6789), via a specific cell surface antibody to activate complement, causes a rapid increase in cytoplasmic Ca2+ detectable within 5-10 s. It provides a specific method for quantifying cytoplasmic photoprotein. As a result new insights into the role of intracellular Ca2+ in cell physiology and pathology have been established.

Photoelectrode with a very short time-constant for recording intracerebrally Ca2+ transients at a cellular level.

In order to study calcium transients in the central nervous system of vertebrates a microphotoelectrode was designed. It is composed of three channels, through the first aequorin is perfused into the extracellular space under constant pressure, the second is an optical glass light-conducting channel, and the third a classical NaCl-filled recording pipette. The light emitted by the interaction of the injected aequorin with the local extracellular calcium is transmitted through the optic fiber to a photomultiplier of high sensitivity.